PMID- 9754836
TI - Chemistry and pharmacology of hallucinogens, entactogens and stimulants.
AB - Amphetamines, tryptamines, phencyclidines, tetrahydrocannabinol and substances of
the ecstasy group are characterized as stimulants, hallucinogens and entactogens.
The various effects of each group and their mode of action in different
transmitter systems are described. 28 new compounds of the amphetamine and
tryptamine series has been calculated, which exceed the hallucinogenic effects of
mescaline. The different pathways of the metabolism of MDMA (ecstasy) and MDE in
humans may probably explain their individual effects.
PMID- 9754837
TI - Behavioral studies of hallucinogenic drugs in animals: implications for
schizophrenia research.
AB - Schizophrenic and schizotypal patients exhibit deficits in the habituation and
prepulse inhibition (PPI) of startle responses, providing operational measures of
the sensorimotor gating or filtering deficits suggested to contribute to
cognitive disorganization in these patients. In rats, hallucinogens, entactogens,
and NMDA antagonists share the ability to both retard startle habituation and
disrupt PPI. Extensive pharmacological studies in rats have indicated that the
effects of hallucinogens on habituation are mediated by direct agonist actions at
5-HT2 receptors. The effects of the entactogens on both habituation and PPI
reflect indirect agonist actions due to the stimulation of presynaptic serotonin
release. These observations in rats have supported the development of 5-HT2A
antagonists for the treatment of schizophrenia. Animal studies have shown that
PPI is modulated by multiple interacting neurotransmitters, including
dopaminergic, serotonergic, cholinergic, GABAergic, and glutamatergic systems
within cortical, limbic, striatal, and brainstem structures. The effects of PCP
and other NMDA antagonists on PPI are insensitive to either dopaminergic or
serotonergic antagonists, but are reduced by atypical antipsychotics such as
clozapine, olanzapine, and Seroquel. Thus, the PCP model of schizophrenia-like
deficits in sensorimotor gating offers promise for the identification and
neurobiological investigation of atypical antipsychotics. The cross-species study
of homologous gating functions, such as habituation and PPI, in animal models and
psychiatric patients provides novel opportunities for the exploration of
neurobiological substrates relevant to the group of schizophrenias.
PMID- 9754838
TI - The standardized psychometric assessment of altered states of consciousness
(ASCs) in humans.
AB - The APZ questionnaire was developed in order to explore hypotheses on ASCs. First
-- in a series of 11 experiments using different induction methods on N = 393
healthy subjects -- the hypothesis was tested that ASCs have major dimensions in
common irrespective of the mode of their induction. In the International Study on
Altered States of Consciousness (ISASC) the external validity of the experimental
results was assessed. The ISASC was carried out on a total of N = 1133 subjects
in six countries. The main results of the experimental studies were corroborated
in the field studies. The results can be summarized as follows: the common
denominator of ASCs is described by three oblique dimensions, designated as
"Oceanic Boundlessness (OSE)", "Dread of Ego Dissolution (AIA)" and "Visionary
Restructuralization (VUS)". The reliability and validity of the scales are
satisfactory. Tested versions of the APZ scales are available in English (UK,
USA), German, Italian and Portuguese. Psychometrically as yet untested versions
exist in Dutch, Finnish, French, Greek, Spanish and Russian. The APZ
questionnaire has become the international standard for the assessment of ASCs,
thus helping to integrate research. A psychometrically improved version exists in
German (OAV questionnaire). The BETA questionnaire, which measures the dimensions
"Vigilance Reduction (VIR)" and "Auditive Alteration (AVE)" is also available in
German. These dimensions are most likely etiology-dependent.
PMID- 9754839
TI - Blood flow and cerebral laterality in the mescaline model of psychosis.
AB - The psychological, neuropsychological, and neurometabolic effects of the
hallucinogenic agent mescaline were investigated in 12 normal male volunteers.
Between 3 1/2 and 4 hours after drug intake, mescaline produced an acute
psychotomimetic state, as measured by the BPRS and PDS-P. The APZ questionnaire
revealed the specific effects of mescaline in the visual system.
Neuropsychological effects were studied with a face/non-face decision task with
known right hemisphere advantage, in which mescaline induced a decrease in
functioning of the right hemisphere. In functional brain imaging using SPECT,
mescaline produced a "hyperfrontal" pattern with an emphasis on the right
hemisphere, which was correlated with mescaline-induced psychotomimetic
psychopathology. Our findings question the validity of the concept of
hypofrontality as an explanation for acute psychotic symptomatology.
PMID- 9754840
TI - Advances and pathophysiological models of hallucinogenic drug actions in humans:
a preamble to schizophrenia research.
AB - Recent research into the pharmacological mechanism of hallucinogens (LSD,
psilocybin) and dissociative anesthetics (PCP, ketamine) suggest that multiple
neurotransmitter systems are involved in drug-induced and possibly also in
naturally occurring psychoses. Specifically, animal models suggest that a
dysbalance between serotonin, glutamate, and dopamine in the limbic cortico
striato-thalamic circuitry may be critical to psychotic symptom formation. To
test this hypothesis, psychometric measures and metabolic PET investigations were
performed (1) with FDG to elucidate the common neuronal substrates of different
hallucinogens, (2) with specific receptor ligands before and after pretreatment
with specific receptor antagonists to explore the putative interactions of
hallucinogens with various neurotransmitter systems. Our data demonstrate that
the neuronal substrate of normal and abnormal thought and behavior is associated
with a distributed neuronal network and with multiple interactive
neurotransmitter systems. The data also support the view that the hallucinogen
challenge paradigm constitutes a powerful tool for elucidating the
pathophysiology of neuropsychiatric disorders.
PMID- 9754841
TI - The NMDA antagonist model for schizophrenia: promise and pitfalls.
AB - Drug models have been extensively used to study the pathophysiology of
schizophrenia. While they provide good insight into the neurobiology of this
disorder, they have several shortcomings, which if known, help in the
interpretation of results. In this paper we will discuss these shortcomings in
general, and in relation to the N-methyl D-aspartate antagonist model for
schizophrenia. This model has recently received a great deal of attention since
both phencyclidine and the structurally related drug ketamine, produce symptoms
that extend beyond psychosis per se to include other symptoms associated with
schizophrenia. In fact, subanesthetic doses of ketamine in healthy individuals
produce not only paranoia and perceptual alterations but also thought disorder,
negative symptoms, cognitive deficits, as well as impairment on a number of
electrophysiologic tests known to be abnormal in schizophrenia. These effects of
ketamine will be discussed with a particular emphasis on implications for the
pathophysiology and therapeutics of this disorder.
PMID- 9754842
TI - Cannabinoid/anandamide system and schizophrenia: is there evidence for
association?
AB - Cognitive impairments during psychotic episodes are assumed to be caused not only
by one single putative classical neurotransmitter dysfunction but also to be due
to an impaired equilibrium of the interaction between different neurobiological
generators of cognitive processes. Here, the perceptual abnormalities induced by
psychotogenic agents play a major role as tools for understanding model
psychoses. The recently discovered cannabinoid receptor system with its
endogenous ligand anandamide can be regarded as an extremely relevant regulation
system, a dysfunctionality of which may explain at least one subtype of
endogenous psychoses. The present paper discusses the possible associations
between the endogenous anandamide/cannabinoid system and schizophrenic psychoses.
Neuropsychological experiments with the 3-D inversion paradigm were performed in
healthy volunteers intoxicated with delta9-Tetrahydrocannabinol (delta9-THC). The
3-D inversion paradigm represents a visual illusion of binocular depth
perception. Such an inversion occurs in many cases, especially when objects with
a higher degree of familiarity (e.g. photographs of faces) are displayed. It is
assumed that cognitive factors override the binocular disparity cues of
stereopsis. We tested the hypothesis that, during psychotic and related
prepsychotic states, the human CNS is unable to correct implausible perceptual
hypotheses. Our study provides evidence of strong similarities between data
acquired from patients, suffering from productive schizophrenic psychoses and
delta9-THC-intoxicated healthy volunteers, as concerns disturbances in the
internal regulation of perceptual processes.
PMID- 9754843
TI - Methodological issues of human experimental research with hallucinogens.
AB - Human experimental research with hallucinogenic drugs is potentially able to
identify linking variables between the psycho(patho)logical conditions and
neurobiological alterations involved in both pharmacologically induced and
naturally occurring acute psychotic states. A number of methodological aspects
should be considered when planning modern experimental studies with
hallucinogenic drugs. The issues of subject selection, repeated measures, and
adequate control groups are discussed in this paper. Examples of recent
experimental studies are presented which take these aspects into account. The
first study examined psychopathological changes, facial expression and semantic
priming effects during a psilocybin-induced state. In the second study, semantic
priming effects after intake of psilocybin, 3,4-methylenedioxyethylamphetamine
(MDE), and d-methamphetamine were investigated. Results confirmed time-dependent
effects of psilocybin and the restriction of increased priming effects in the
psilocybin group.
PMID- 9754844
TI - Fluvoxamine or placebo in the treatment of panic disorder and relationship to
blood concentrations of fluvoxamine.
AB - A six-week double-blind placebo-controlled trial of fluvoxamine was undertaken in
46 patients suffering from panic disorder with or without agoraphobia diagnosed
by DSM-III-R guidelines. Average daily dosage of fluvoxamine was 160 mg, with a
highest permitted dose of 300 mg/day. Weekly evaluation included a diary in which
the number, severity, and duration of full-blown and limited panic attacks and
the duration and severity of anticipating fear, CAS, GAS, CGI, HAM-D, adverse
effects and the number of capsules not taken were noted. Fluvoxamine was not
significantly superior to placebo with regard to the main outcome criterion,
i.e., the reduction in the number of panic attacks, but it was significantly more
effective with regard to the diminution in the number of limited panic attacks
and showed a tendency to significance in respect of GAS and CGI. Plasma levels of
fluvoxamine were measured at the end of week one and at the end of the study.
Most patients with complete remission at the end of the study were found in the
verum group with plasma fluvoxamine levels ranging from 10 to 100ng/ml. It is
suggested that therapeutic response might be maximized by monitoring fluvoxamine
concentrations in blood.
PMID- 9754845
TI - Combined treatment of schizophrenic psychoses with haloperidol and valproate.
AB - In accordance with a previous study of adjuvant effects of the anticonvulsant
carbamazepine (CBZ) on the neuroleptic treatment of schizophrenic psychoses, the
effects of valproate (VPA) were tested in a randomly assigned double-blind,
placebo-controlled study. Apart from a (statistically nonsignificant)
psychopathological deterioration following discontinuation of VPA while on
continuous neuroleptic mediation after four weeks and a statistically significant
effect on "hostile belligerence", no overall therapeutic effects of the
combination of haloperidol (HPD) with VPA were observed under controlled
conditions. Unlike the results with CBZ, concomitant use of VPA led to an even
higher consumption of haloperidol and biperiden and to a higher rate of
extrapyramidal symptoms compared with the corresponding placebo group, although
these differences did not attain statistical significance. In regard to use of
the sedative neuroleptic chlorprothixene, there was a trend toward lower doses in
the VPA group than in the placebo group. From these results, adjuvant effects
like those of carbamazepine in the neuroleptic treatment of schizophrenic
psychoses could not be confirmed for valproate in the present study. However, the
trend toward lower doses of sedative medication and observed effects on "hostile
belligerence" may indicate sedative and/or antimanic properties of valproate
which have recently been demonstrated in several controlled studies.
PMID- 9754846
TI - A risk for obstruction of the airways in the parenteral use of levomepromazine
with benzodiazepine.
AB - Arrhythmogenic effects of phenothiazines appear to be associated with sudden
death, whereas respiratory complications have received little attention. In this
report we describe 5 cases with accompanying obstruction of the airways after
intramuscular injections of levomepromazine (LPZ), a potent sedative
phenothiazine, in combination with intravenous injections of benzodiazepine (BZ)
during a 3-month period in a psychiatric intensive care unit. Two out of 5 cases
were unpredictable because obstruction of the airways occurred 2 hours or more
after the last injection. As compared with patients who received parenteral
(intravenous or intramuscular) injections during the same period, the dose of
intramuscular LPZ was significantly large in the 5 cases with obstruction of the
airways. All 5 of these cases received intramuscular LPZ 0.52 mg/kg or more. In
contrast, there was no patient with obstruction of the airways who received only
intramuscular LPZ, the combination of LPZ and HDL, or BZ and HDL. The occurrence
of obstruction of the airways among patients who received both intramuscular LPZ
and intravenous BZ was significantly higher than among patients who received
other drug regimes. These preliminary results suggest that the intramuscular use
of LPZ with intravenous BZ may be a risk for obstruction of the airways.
PMID- 9754847
TI - The influence of alprazolam on the monoaminergic neurotransmitter systems in
dysthymic patients. Relationship to clinical response.
AB - The effects of alprazolam (1.5 mg/die) on the levels of the monoaminergic
neurotransmitter metabolites, on the activity of the hypothalamic-pituitary
adrenal axis and on clinical outcome in subjects with primary late-onset
dysthymia were investigated. Drug treatment significantly decreased plasma and
urinary cortisol levels, serotonin platelet-bound and urinary 3-methoxy-4
hydroxyphenylglycol concentrations, while it increased plasma homovanillic acid
(HVA) concentrations. Significant relationships were observed between
neurochemicals and global scores or some items of the Hamilton Depression Rating
Scale, before and after treatment. Patients responded positively (73%) to the
therapy; clinical outcome was significantly correlated with plasma and urinary
HVA levels. Collected data seem to support the hypothesis that central
monoaminergic systems are in part involved in therapeutic response to alprazolam.
PMID- 9754848
TI - Evaluation of sedative effects of single and repeated doses of 50 mg and 150 mg
tolperisone hydrochloride. Results of a prospective, randomized, double-blind,
placebo-controlled trial.
AB - Sedative effects of single and repeated doses of 50 mg and 150 mg tolperisone
hydrochloride (Mydocalm), a centrally active muscle-relaxing agent, were
evaluated in a placebo-controlled double-blind clinical trial. A total of 72
healthy young adults balanced by sex were randomized to receive 50 mg or 150 mg
tolperisone hydrochloride or placebo t.i.d. for a period of 8 days. Control
examinations were performed in the mornings of days 1 and 8 before intake of the
morning dose and at 1.5, 4 and 6 hours postdose. The psychomotoric test battery
used in this trial revealed no sedative effects of tolperisone hydrochloride in
the given doses at any control examination. Subjective mood ratings quantified by
the Welzel Colored Scales were not impaired either. The lack of differences in
sedative potentials of tolperisone hydrochloride and placebo was confirmed by
tests on differences and by tests on equivalence using 95% CI. The present study
substantiates clinical experience and previous clinical trials demonstrating that
tolperisone hydrochloride, though being a centrally active muscle relaxant, does
not cause any sedation and does not impair reaction times.
PMID- 9754849
TI - Choreoathetoid movements associated with rapid adjustment to methadone.
AB - Choreatiform hyperkinesias are known to be occasional movement abnormalities
during intoxications with cocaine but not opiates. This is a case report of
euphoria and choreoathetoid movements both transiently induced by rapid
adjustment to the selective mu-opioid receptor agonist methadone in an inpatient
previously abusing heroine and cocaine. In addition, minor EEG abnormalities
occurred. Possible underlying neurobiological phenomena are discussed.
PMID- 9754850
TI - Severe akathisia during olanzapine treatment of acute schizophrenia.
AB - Olanzapine is a newly developed atypical neuroleptic with a marked affinity to
the 5-HT2, D2 and D4 dopamine receptors. Like other atypical neuroleptics
olanzapine is considered to show a reduced prevalence of extrapyramidal side
effects when compared to classical neuroleptic drugs. We report on three patients
with acute schizophrenia, who developed severe akathisia during treatment with
olanzapine (20-25 mg/d). In two of these cases akathisia resolved after
withdrawal of olanzapine and substitution by a classical or an atypical
neuroleptic agent, respectively. In one of these patients olanzapine was well
tolerated when reintroduced in combination with lorazepam after complete
remission of akathisia. In the third patient akathisia was sufficiently
controlled by dose reduction. Akathisia is generally considered to result from D2
dopamine receptor antagonism. In the case of atypical neuroleptics such as
olanzapine a low but still considerable D2 dopamine receptor occupancy may be
compensated by the 5-HT2 antagonism. However, this mechanism may fail under
certain circumstances, in particular if D2 dopamine antagonism exceeds a certain
threshold. One should therefore be aware of possible extrapyramidal side effects
with olanzapine that are reduced compared to classical neuroleptic drugs but not
completely eliminated.
PMID- 9754851
TI - Acute clozapine overdose: plasma concentration and outcome.
AB - Clozapine is a tricyclic dibenzodiazepine derivative that is classified as an
"atypical neuroleptic" drug for treatment of psychotic diseases. A 19-year-old
schizophrenic female, treated with 400 mg clozapine per day, was admitted to the
emergency department after ingestion of 5000 mg (50 x 100 mg tablets) of
clozapine. Clozapine plasma level 2.5 hours after ingestion was 3.8 microg/ml
(normal range 0.2-0.7 microg/ml) and very high in gastric lavage. Contrary to
reported cases with such high plasma concentrations the patient suffered only
from somnolence with intermittent periods of agitation and a mild anticholinergic
syndrome with sinus tachycardia and slight hypotension. After detoxication with
gastric lavage and short-term administration of pyridostigmine she remained
stable, and 24 hours after ingestion she was transferred to the psychiatric unit
without further sequelae. To prevent late-onset complications she was carefully
monitored for five days. The clozapine plasma level 24 hours after the first
measurement was normal. This case and others reported in the literature confirm
that signs and symptoms after clozapine intoxication are variable and that high
plasma levels are not lethal in every case.
PMID- 9754852
TI - Hepatitis caused by antidepressive therapy with maprotiline and opipramol.
AB - There are few published reports of antidepressive therapy induced hepatotoxicity.
In most cases antidepressants cause only slight elevation of liver enzymes
without clinical relevance. However, our patient with recidivation of unipolar
depressive disorder developed severe laboratory abnormalities and clinical
symptoms during therapy with maprotiline (Ludiomil) and opipramol (Insidon). To
our knowledge, this is the first case report of bioptically proven severe acute
hepatitis caused by these antidepressants. After their withdrawal, the patient's
fatigue symptoms, scleric jaundice, and marked increase of liver enzymes
completely disappeared. Hepatic side effects should be considered during
antidepressive therapy with maprotiline and opipramol especially when additional
clinical symptoms emerge.
PMID- 9754853
TI - Clozapine treatment of HIV-associated psychosis--too much bone marrow toxicity?
PMID- 9754854
TI - Solving mysteries of the bioeffects of nonionizing radiation.
PMID- 9754855
TI - Biological effects of amplitude-modulated radiofrequency radiation.
AB - Users of mobile telephones are exposed to radiofrequency radiation. One of the
questions still open today is whether amplitude-modulated radiofrequency signals
from digital phones exert specific bioeffects different from those of continuous
(unmodulated) radiofrequency radiation. This paper reviews recent literature on
the bioeffects of amplitude-modulated radiofrequency radiation, from cells to
humans. The consistency of the results is discussed, and exposure parameters are
compared to identify possible biologically active forms of amplitude modulation.
Several studies have reported findings consistent with effects on the nervous
system and cancer-related biological processes. However, the methods and exposure
parameters vary widely, and no independent replications of the positive findings
have been reported. The results available today fail to support the existence of
well-defined modulation-specific bioeffects from exposure to radiofrequency
radiation. Additional systematic studies are needed to identify possible
reproducible modulation-dependent effects and biologically active modulation
parameters.
PMID- 9754856
TI - Meta-analyses of non-Hodgkin's lymphoma and farming.
AB - OBJECTIVES: This study examined the association between non-Hodgkin's lymphoma
(NHL) and farming. METHODS: A series of meta-analyses of peer-reviewed studies
was performed using 36 studies published between 1982 and 1997. Prior to the meta
analyses, all the studies were reviewed and evaluated for heterogeneity and
publication bias. Combined relative risks (RR) were calculated using the random
effect model. RESULTS: The combined RR was 1.10 [95% confidence interval (95% CI)
1.03-1.19] for all the studies and 0.93 (95% CI 0.82-1.06) for studies involving
female farmers. Significant heterogeneity was detected for study design and
country of study among the studies. Significantly elevated RR values were
obtained for case-referent studies (combined RR 1.19, 95% CI 1.06-1.33) and for
studies conducted on farmers residing in the United States (combined RR 1.26, 95%
CI 1.15-1.37). These findings were not influenced by a publication bias.
CONCLUSIONS: The findings suggest that male farmers residing in the United States
have a slightly elevated risk of contracting NHL. Commonly experienced exposures
that might contribute to the occurrence of NHL in this group include infectious
microorganisms, herbicides, and insecticides.
PMID- 9754857
TI - Determinants of asthma in a farming population.
AB - OBJECTIVES: This study examined the determinants of asthma in a population of
farmers, including as a crude indicator of genetic predisposition "history of
asthma in next-of-kin" (family history), and exposure factors such as animal
production and smoking. METHODS: In a cross-sectional study of 8482 farmers or
farmers' spouses in Norway a questionnaire with information on asthma among the
subjects and their next-of-kin, production type and farming activities, exposures
outside farming, and smoking was applied. Spirometry was performed. RESULTS: The
lifetime prevalence of self-reported asthma in the population was 6.3%.
Significant risk factors for current asthma were asthma among next-of-kin, asthma
as child or adolescent, animal production, and age. In a comparison with subjects
with no family history of asthma and no animal production the adjusted odds ratio
for current asthma in never smokers was 1.9 [95% confidence interval (95% CI) 0.4
8.9] for subjects with family history only, 2.2 (95% CI 1.1-4.2) for subjects
with animal production only, and 6.3 (95% CI 3.1-13.1) for subjects with both
factors. A combination of animal production, smoking, and a positive family
history gave an odds ratio of 8.1 (95% CI 4.0-16.2) for current asthma.
CONCLUSIONS: The study can be interpreted as support for the hypothesis of an
interaction between genetic factors and exposure factors in the causation of
asthma. Since familial associations may be exposure-related, the necessity of
considering indicators of both inheritance and exposure in epidemiologic studies
of asthma is emphasized.
PMID- 9754858
TI - Mortality and cancer incidence among Swedish paint industry workers with long
term exposure to organic solvents.
AB - OBJECTIVES: The aim of this update on a cohort of male paint industry workers was
to determine whether an excess of mortality and incidence of lymphatic and
hematopoietic tumors, particularly multiple myeloma, still exists, and, if so, to
determine if it is due to exposures occurring before the mid-1950s, when benzene
disappeared as a solvent in the Swedish paint industry. METHODS: The cohort of
411 men who had worked in the Swedish paint industry and had been exposed to
organic solvents for at least 5 years during 1955-1975 was followed from 1961 to
1994 for causes of death in the mortality register and from 1961 to 1992 for
cases of cancer in the Swedish cancer register. RESULTS: The number of paint
industry workers who had died, plus the number of deaths in the major disease
groups and the number of cancers reported to the cancer registry, was close to
the expected. The incidence of prostatic cancer increased somewhat [standardized
incidence ratio (SIR) 1.5, 95% confidence interval (95% CI) 1.0-2.2]. Among the
workers first employed in 1956 or earlier, there was an increase in both the
incidence and mortality from all lymphatic and hematopoietic tumors [SIR 2.3, 95%
CI 1.0-2.2; standardized mortality ratio (SMR) 2.0, 95% CI 0.7-4.4]. The excess
was particularly marked for multiple myeloma (SIR 3.8, 95% CI 0.8-11; SMR 4.4,
95% CI 0.9-13). CONCLUSIONS: Employment in the Swedish paint industry before 1957
may have entailed some excess risk of lymphatic and hematopoietic tumors,
particularly multiple myeloma. A significant excess of prostatic cancer was not
linked to any particular employment period and deserves further investigation.
PMID- 9754859
TI - Immunologic and renal markers among photogravure printers exposed to toluene.
AB - OBJECTIVES: This study assessed immunologic and early renal effects of chronic
toluene exposure. METHODS: In a longitudinal study of 92 printers and 74
referents, 145 subjects had pre- and poststudy samples of blood and urine taken
for the following measurements: immunoglobulin E (IgE), antiglomerular basement
membrane (anti-GBM) and antilaminin (anti-LAM) antibodies in blood; creatinine
and beta2-microglobulin in blood and urine; and microalbumin, N-acetyl-b-D
glucosaminidase (NAG) and alanine-aminopeptidase in urine. Creatinine clearance
was calculated according to the Cockroft-Gault formula. Eight-hour personal air
samples were collected twice to assess present exposure to toluene. A job
exposure matrix was developed to estimate past cumulative exposure. Information
about potential confounders was recorded by questionnaire. Multiple regression
analysis was performed to study dose-effect relations adjusted for age and
smoking. RESULTS: No subject was positive for anti-GBM antibodies, and only 12
were positive for anti-LAM. No relation was observed between the markers studied
and present exposure to toluene except that creatinine clearance was higher among
the exposed subjects than among the referents. A dose-response relation was
observed between cumulative toluene exposure and both IgE and NAG excretion. No
interaction was observed between hypertension and exposure, but the relationship
with NAG did not persist when subjects with hypertension were excluded. Past or
present exposure did not alter the 2-year trend of any marker studied.
CONCLUSIONS: According to the results of this study, toluene at 50 ppm is not
related to detectable renal dysfunction. The increased IgE levels associated with
present and past exposure require further investigation.
PMID- 9754860
TI - Occurrence of carpal tunnel syndrome among slaughterhouse workers.
AB - OBJECTIVES: The aim of this study was to examine the risk of carpal tunnel
syndrome (CTS) among workers with daily occupational exposure to high-force and
high-velocity manual work. METHODS: The study was carried out retrospectively
among a cohort of 1591 workers employed at a slaughterhouse or at a chemical
factory; 1141 persons (71.7%) participated. Workers not doing tasks in
slaughtering or meat processing constituted the reference group. Exposure
assessments were made for 46 different tasks in slaughtering and meat processing
from video-based observations at the workplace. CTS was diagnosed if there were
current symptoms typical of CTS in combination with positive neurophysiological
signs of CTS or if the subject had previously been operated on for CTS. RESULTS:
Altogether 1.6% of the reference group, 5.1% of the nondeboning slaughterhouse
workers [prevalence ratio (PR) 3.23, 95% confidence interval (95% CI) 1.3-7.99]
and 7.8% of the deboning slaughterhouse workers (PR 4.91, 95% CI 2.03-11.81) had
CTS. Increased risk estimates persisted after adjustment for other potential risk
factors by logistic regression. The prevalence of CTS in the dominant hand was
equally increased in both groups of slaughterhouse workers (but only
statistically significant for the workers in deboning tasks), while the
prevalence of CTS in the nondominant hand was significantly increased only among
the slaughterhouse workers in deboning tasks. CONCLUSIONS: This study supports
the hypothesis that daily high-velocity and high-force manual work is a risk
factor for CTS.
PMID- 9754861
TI - From a unidimensional to a bidimensional concept and measurement of workers'
safety behavior.
AB - OBJECTIVES: This study examines the concept and measurement of worker's safety
behavior. It shows that the traditional concept of safety behavior centered on
workers' carefulness or compliance with safety rules is limited and proposes that
an additional dimension, namely, workers' safety initiatives, be taken into
account. METHODS: Confirmatory factor analyses were carried out for a random
sample of 828 workers drawn from 9 manufacturing facilities located in the
province of Quebec (Canada). RESULTS: A 2-correlated congeneric factor model gave
parameters in the expected direction, but the overall model was unable to reach a
good fit. Separate construct analyses showed that compliance with safety rules is
not a consistent dimension. The safety-initiatives dimension achieved a good fit
with a high composite reliability (p=0.85). CONCLUSIONS: Workers' compliance with
safety rules was not structured as a unitary dimension; therefore a selective
process of safety-rules compliance by workers is suggested. Each category of
safety rules should be considered as 1 single dimension and measured by several
specific indicators. Indicators for safety initiatives provide high reliability,
and, since this dimension is an important predictor of effectiveness in accident
prevention, the items tested provide a better measurement than those previously
published.
PMID- 9754862
TI - Combined effects of shift work and life-style on the prevalence of insomnia,
sleep deprivation and daytime sleepiness.
AB - OBJECTIVES: The combined effects of age, leisure-time physical activity, smoking,
alcohol consumption, and different forms of shift work on the prevalence of sleep
complaints and daytime sleepiness were studied among workers in industry,
transport, and traffic. METHODS: Altogether 3020 subjects were studied using a
psychosocial questionnaire. The participants were currently employed men, aged 45
60 years, from a postal and telecommunication agency, the railway company, and 5
industrial companies. On the basis of a factor analysis of an 11-item sleep
questionnaire, the sleep complaints were grouped into the categories of insomnia,
sleep deprivation, daytime sleepiness, and snoring. The importance of the shift
schedule, age, and life-style factors as simultaneous predictors of the
complaints was studied in a logistic regression analysis and an analysis of
covariance. RESULTS: The prevalence of insomnia, sleep deprivation, and daytime
sleepiness depended significantly on the shift system. All sleep complaints were
more common in 2- and 3-shift work and in irregular shift work than in day work.
The prevalence of daytime sleepiness was 20-37%, depending on the shift system.
Leisure-time physical activity and alcohol consumption were the most important
life-style factors predicting all sleep complaints, except snoring. The effects
of physical activity and alcohol consumption differed for different shift
schedules. CONCLUSIONS: Different shift systems, also 2-shift work and permanent
night work, seem to increase the frequency of sleep complaints. Especially 3
shift work seems to interact with life-style factors by increasing the adverse
effects and decreasing the beneficial effects on sleep and sleepiness.
PMID- 9754863
TI - Experience with a vocabulary test for workers previously and still exposed to
styrene.
AB - OBJECTIVES: This study examined the possible influence of styrene exposure on the
results of vocabulary tests because verbal ability is assumed to be relatively
resistant to the toxic effects of organic solvents and short vocabulary tests are
used as "hold tests" in many neurobehavioral epidemiologic studies, METHODS: To
evaluate the chronic neurotoxic effects of styrene, a vocabulary test was
administered to a group of still-exposed workers (N=27) and an earlier exposed
group of workers (N=90). A self-administered questionnaire was filled out on life
events, general health, educational level, and amount of education. The still
exposed group had a mean exposure duration of 4700 hours, and that for the
formerly exposed group was 3610 hours. RESULTS: The vocabulary score of the still
exposed group was significantly lower [12.5 (SD 2.9, range 6-18)] than that of
their former colleagues [14.3 (SD 3.4, range 8-22)], even though they originally
belonged to the same group and had done the same tasks. The exposure duration
explained a significant part of the vocabulary results, resulting in decreasing
vocabulary scores even when the influence of years of education and age was taken
into account. Even after correction for the possible influence of having been
laid off or staying at work, there remained a negative influence on the
vocabulary score for the duration of styrene exposure. CONCLUSIONS: The use of
short vocabulary tests as hold tests in cross-sectional studies of solvent
exposed workers may be limited as they seem to lack the essential toxicity
independent property.
PMID- 9754864
TI - Towards the coordination of European research on the carcinogenic effects of
asbestos.
PMID- 9754865
TI - Ligation of selectin L and integrin CD11b/CD18 (Mac-1) induces release of
gelatinase B (MMP-9) from human neutrophils.
AB - OBJECTIVE AND DESIGN: To examine whether ligation of the adhesive receptors -
selectin L and Mac-1 on the neutrophil surface could induce gelatinase B
exocytosis. MATERIALS: Neutrophils were isolated from fresh heparinized blood of
human donors by Gradisol G centrifugation and hypotonic lysis of erythrocytes.
METHODS: Integrin CD1 1b/CD18 and selectin L mediated adhesive interaction of
human neutrophils were mimicked by binding antibodies to these receptors on the
surface of isolated leukocytes. Neutrophils (5 x 10(6)/ml) were incubated with
antibodies against selectin L (40/microg/ml) and CD18 or CDI 1b (10microg/ml).
The secretion of gelatinase was examined by determination of enzyme activity and
gelatin substrate zymography of cell supernatants. RESULTS: Ligation of selectin
L, CD18 and CD11b integrin subunits by monoclonal antibodies induced a rapid
release of 24.6+/-1.8% (p<0.005), 24.0+/-2.9% (p<0.001) and 22.7+/-2.0% (p <
0.005) of total neutrophil gelatinase, respectively as compared with 11.1+/-1.6%
in the control. These values were equivalent to N-formyl-methionylleucyl
phenylalanine (fMLP)-stimulated secretion of gelatinase. Under these experimental
conditions there was no significant beta-glucuronidase release from azurophilic
granules. Gelatinase exocytosis elicited by selectin L and CD18 ligation was
inhibited by 82.7+/-10.1% and 49.3+/-5.9%, respectively after preincubation of
the neutrophils with 10 microM herbimycin A. CONCLUSIONS: Ligation of selectin L
and integrin CD11b/ CD18 provides stimulatory signals to neutrophils which induce
secretion of gelatinase B that may facilitate their transmigration into sites of
inflammation.
PMID- 9754866
TI - Ca2+-ATPase inhibitors and PKC activation synergistically stimulate TNF-alpha
production in RBL-2H3 cells.
AB - OBJECTIVE AND DESIGN: To investigate the effect of Ca2+-ATPase inhibitors on the
production of TNF-alpha in rat basophilic leukemia (RBL-2H3) cells. MATERIAL: Two
Ca2+-ATPase inhibitors, thapsigargin (TG) and cyclopiazonic acid (CPA), and three
hydroquinone-antioxidants, 2,5-di-(tert-butyl)-1,4-hydroquinone (DTBHQ), 2,5-di
(tert/amyl)-1,4-hydroquinone (DTAHQ), 2-(tertbutyl)-1,4-hydroquinone (MTBHQ) were
used. TREATMENT: Cells were treated with TG, CPA, DTBHQ, DTAHQ and MTBHQ for 3 h
in the presence of 12-Otetradecanoylphorbol-13-acetate (TPA) and released TNF
alpha from the cells was measured (n > or = 4). RESULTS: All Ca2--ATPase
inhibitors (TG, CPA, DTBHQ and DTAHQ) induced TNF-alpha release in a dose
dependent manner. TNF-alpha release was inhibited by treatment with protein
kinase C inhibitors (staurosporine, Ro31-8220, calophostin C) (p < or = 0.05). In
contrast, MTBHQ, which does not induce increases in [Ca2+]i, did not induce the
release of TNF-alpha. TNF-alpha release induced by DTBHQ and CPA was inhibited by
treatment with actinomycin-D, the immunosuppressant FK506 and the glucocorticoid
dexamethasone (p < or = 0.01). CONCLUSIONS: These results suggest 1) that [Ca2+]i
increase and subsequent activation of protein kinase C is necessary for the
release of TNF-alpha, and they work synergistically, 2) that the TNF-alpha
release induced by Ca2+-ATPase inhibitors can be regulated at the transcriptional
level.
PMID- 9754867
TI - Further studies on anti-inflammatory activity of phycocyanin in some animal
models of inflammation.
AB - OBJECTIVE: To examine the effects of C-phycocyanin, a pigment found in blue-green
algae which acts as an antioxidant in vitro and in vivo, in different animal
models of inflammation. MATERIAL: Male Sprague Dawley rats and OF1 mice were
used. TREATMENTS: Oedema was induced by: a) AA (0.5 mg/ear) or TPA (4 microg/ear)
in the mouse ear b) carrageenan injection (0.1 mL of 1% suspension) in the rat
paw (+/-adrenalectomy) and c) cotton pellet implantation in the rat axilla.
Phycocyanin (50-300mg/kg, p.o.) or indomethacin (1 mg/ear or 3-10mg/kg, p.o.) as
control were tested in the four animal models. METHODS: Measurement of the
increase in the weight (mg) of 6 mm ear punch biopsies from treated ears were
made in comparison to control ears, together with myeloperoxidase (MPO) activity
as an index of neutrophil infiltration. The increase in the paw thickness (mm)
was measured with a dial caliper. Cotton pellet was implanted and seven days
afterwards the granuloma was removed and the dry weight was determined. Acute
toxicity was studied in mice and rats. Statistics were performed using one-way
analysis of variance with the Duncan Multirange test. RESULTS: Phycocyanin
reduced significantly (p < 0.05) and in a dose-dependent manner ear oedema
induced by AA and TPA in mice as well as carrageenan-induced rat paw oedema (both
in intact and adrenalectomized animals). In the TPA test, phycocyanin also
reduced MPO content. Phycocyanin also exerted an inhibitory effect in the cotton
pellet granuloma test. In the acute toxicity test in rats and mice, even at the
highest dose tested (3000 mg/kg, p.o.), no toxicity was found. CONCLUSIONS:
Phycocyanin shows anti-inflammatory activity in four experimental models of
inflammation. Its antioxidative and oxygen free radical scavenging properties may
contribute, at least in part, to its anti-inflammatory activity.
PMID- 9754868
TI - Sirolimus (rapamycin, Rapamune) and combination therapy with cyclosporin A in the
rat developing adjuvant arthritis model: correlation with blood levels and the
effects of different oral formulations.
AB - OBJECTIVE AND DESIGN: To determine whole blood levels of sirolimus, a macrolide
antibiotic in the rat developing adjuvant arthritis (AA) model after dosing
orally with two different vehicles, and whether combinational doses of sirolimus
and cyclosporin A (CsA) produced additive or synergistic inhibitory effects in
this model. MATERIAL: Male Lewis rats (150-180g). TREATMENT: Arthritis was
induced by the injection (0.5 mg/ rat) of heat-killed Mycobacterium butyricum
suspended in light mineral oil. Drugs were administered orally either in fine
suspension (0.5% Tween 80) or in emulsion (phosal 50 PG in 1% Tween 80) at doses
of 0.1 to 5 mg/kg in a 7 day, MWF or daily regimen. METHOD: Paw volumes (ml) were
measured by automated mercury plethysmograph and sirolimus concentrations in
whole blood were quantitated by liquid chromatography/ mass spectroscopy.
RESULTS: At 72h (7 days after adjuvant) after receiving the third oral dose (4.5
mg/kg p.o.), the phosal vehicle resulted in higher sirolimus blood levels (2.5
ng/ml) than in Tween 80 (1.6 ng/ml). After the rats received the last oral dose
on day 14, (7 total doses of sirolimus at 4.5 mg/kg) the sirolimus blood levels
(2h after the last dose) were about 2 times higher for the phosal dosed rats (9.8
ng/ml) compared to Tween 80 dosed rats (4.6ng/ml). Even 24h after the last dose,
sirolimus blood levels were still elevated in the phosal dosed rats (0.8 ng/ml)
relative to 0.5% Tween 80 dosed rats (0.5 ng/ml). At day 16 in the rat developing
model, sirolimus, when given in phosal vehicle, produced an ED50 of 0.28 mg/ kg
(i.e. inhibition of uninjected paw edema) that was about 5.5 times lower than
using 0.5% Tween 80 as the suspending agent (ED50 = 1.6mg/kg). When combining
sirolimus and CsA using precalculated doses for producing an additive effect in
this adjuvant model, an additive inhibitory effect on uninjected paw edema was
observed at equal combinational doses of 0.5 and 2 mg/kg, respectively.
CONCLUSIONS: The phosal vehicle used in administering sirolimus increases the
absorption and whole blood levels in the rat and the elevated blood levels
correlated positively with the therapeutic effect in the rat developing AA model.
In addition, combination therapy using sirolimus and CsA produced an additive
effect in rat developing AA.
PMID- 9754869
TI - Activation of neutrophil respiratory burst by cytokines and chemoattractants.
Regulatory role of extracellular matrix glycoproteins.
AB - OBJECTIVE AND DESIGN: We investigated the in vitro responsiveness of neutrophils
adherent to fibronectin (FN) and laminin (LM), toward natural pro-inflammatory
and/or phagocyte-activating agents. MATERIALS AND METHODS: Neutrophils from
normal volunteers were layered on polystyrene wells precoated or not with FN
and/or LM and tested for their ability of responding to eleven pro-inflammatory
mediators by evaluation of superoxide anion (O2-) production and adherence.
Results, expressed as mean +/-1SEM, were evaluated by non-parametric analyses
(Mann-Whitney U-test or Kruskal-Wallis non-parametric ANOVA analysis) RESULTS:
Precoating polystyrene wells with LM or FN prevented the plastic-induced
neutrophil (O2-) production. Among eleven agents, tumor necrosis factor-alpha
(TNF, 3.0+/-0.3 nmoles (O2-)/5 x 10(4) neutrophils/180 min, p < 0.001),
granulocyte-macrophage colony stimulating factor (GM-CSF, 2.1+/-0.3 nmoles (O2
)/5 x 10(4) neutrophils/180 min, p < 0.05) and formyl-peptides (fMLP, 2.5+/-0.5
nmoles (O2-)/5 x 10(4) neutrophils/180min, p < 0.01) caused massive (O2-)
production by neutrophils adherent to FN. None of the mediators was capable of
triggering (O2-) production by neutrophils adherent to LM. LM, mixed with FN to
coat wells, caused a dose-dependent inhibition of the oxidative burst triggered
by TNF (IC50 LM: 0.84+/-0.03 microg, mean+/-1 SEM), GM-CSF (IC50 LM: 0.36+/
0.16micro/g, mean+/-1SEM) and fMLP (IC50 LM: 0.54+/-0.008 microg, mean+/-1 SEM).
To the contrary, fMLP (85.5+/-27.7%), TNF (163.1+/-67.5%), and GM-CSF (121.8+/
66.4%) caused a significant augmentation of neutrophil adherence to LM,
suggesting that LM-mediated inhibition of neutrophil oxidative metabolism does
not depend on the concomitant LM-induced inhibition of neutrophil adherence.
Finally, neither solid-phase FN nor LM affected (O2-) production by neutrophils
in response to immune complexes. CONCLUSIONS: Extracellular matrix glycoproteins
dictate the response of neutrophils to soluble mediators but not to immune
complexes. This appears to be a biologically meaningful mechanism to localise the
risk of cellular reactions to mediators that are able to diffuse easily from
tissue sites of generation and become widely distributed in body fluids during
inflammatory diseases.
PMID- 9754870
TI - Increased release of ATP from endothelial cells during acute inflammation.
AB - OBJECTIVE AND DESIGN: The effects of lipopolysaccharide (LPS), a potent
inflammatory mediator, on the shear stress stimulated release of adenosine
triphosphate (ATP) were investigated on endothelial cells from human umbilical
vein in primary culture. METHODS: Human umbilical vein endothelial cells (HUVEC)
in primary cultures were subjected to shear stress using a cone and plate
apparatus. ATP released by the cells was measured by luminometry, using a
luciferin-luciferase assay. RESULTS: Under conditions of shear stress alone
(25dyn/cm2), ATP accumulates into the culture medium and reaches a maximum after
3 to 5 min of stimulation (121.7+/-13.2 pmol/ml). The shear stress-stimulated
release of ATP was significantly increased after a 4 h pre-incubation of
endothelial cells with 50 microg/ml (314.4+/-26.7 pmol/ml) and 10microg/ml
lipopolysaccharide (207.7+/-22.2 pmol/ml). Dexamethasone, an anti-inflammatory
glucocorticoid, inhibited the effects of lipopolysaccharide. CONCLUSIONS: These
results show that non-damaged endothelial cells release ATP under experimental
inflammatory conditions and support an early role of extracellular ATP in the
inflammatory process.
PMID- 9754871
TI - Genetic lesions in Drosophila behavioural mutants.
AB - Over the last 30 years, several hundred behavioural mutants have been isolated in
Drosophila. Only a fraction of these are well characterized genetically,
behaviourally, and structurally. From six areas of behaviour a set of 24 well
studied mutants was chosen, in which the behavioural defect is probably caused by
a central dysfunction and not by an impairment of sensory input or motor output.
In all cases, the affected genes can be mutated to more than just a behavioural
phenotype. Most genes in the sample are essential. Thus, phenotypic specificity
is caused by the specificity of the mutation and not by the gene being a
'behavioural gene'. This study investigates how partial functional inactivation
in these loci is brought about genetically. In particular, an attempt is made to
discern whether behavioural mutations affect part of a protein's functional
repertoire, a subset of protein isoforms, or the spatio-temporal expression of a
gene. Not unexpectedly, in view of the predominant use of ethyl methanesulfonate
(EMS) as mutagen, the majority of sampled mutations fall into the first two
categories. The potentially richest source of genetic versatility, the spatio
temporal modulation of promoter activity by enhancers and silencers, has thus
been insufficiently exploited for obtaining behavioural mutants. Various mutagens
are reviewed as to their suitability in inducing selective regulatory mutations.
PMID- 9754872
TI - The cerebellum and postural sensorimotor learning in mice and rats.
AB - Animals with cerebellar damage caused by gene mutations, surgical ablations and
irradiation by X-rays during developmental stages are impaired in maintaining
posture and equilibrium. For most tests, even in animals with total
cerebellectomy, postural sensorimotor learning is not abolished. Simpler
compensatory movements may be adopted. The acquisition of simple sensorimotor
skills occurring after massive damage of the cerebellar cortex may be explained
by the modulatory role of the cerebellar deep nuclei during learning processes or
by the influence of extracerebellar regions taking over lost cerebellar function.
PMID- 9754873
TI - The foraging gene affects adult but not larval olfactory-related behavior in
Drosophila melanogaster.
AB - This study investigates the ability of larvae and adult rover and sitter
Drosophila melanogaster to detect and migrate towards the source of a fly medium
attractant using larval plate assays and an adult olfactory trap assay. Allelic
variation at the foraging locus which encodes a cGMP-dependent protein kinase
(PKG) did not affect larval olfactory response in the larval plate assays. In
contrast, adult males of the sitter mutant for(s2) exhibited an olfactory trap
response (OTR) which was significantly greater than that of males of the wild
type forR strain from which for(s2) was derived and further genetic analysis
showed that this was attributable to the for(s2) allele. The olfactory responses
of fbrR and for(s2) flies to three odours (propionic acid, ethyl acetate and
acetone) in a T-maze assay was normal indicating that they did not have general
olfactory deficits. The finding that adult flies who differ in their PKG enzyme
activities differ in foraging behaviours and olfactory trap responses to yeast
odours suggests that PKG signalling pathways are involved in olfactory related
responses to food.
PMID- 9754874
TI - New functions for nicotinic acetylcholine receptors?
AB - Although the neuronal nicotinic acetylcholine receptor is found in most parts of
the brain, not much is known about its functional significance. At least ten
different subunits are expressed in the central nervous system, theoretically
able to give rise to more than a thousand different receptor subtypes. Despite,
or perhaps because of, this astonishing diversity, the biological role of this
receptor type remains to be investigated. It has recently been found that a
mutated alpha4-subunit is associated with an inherited epilepsy syndrome. A
missense mutation replacing a serine in position 248 of the second transmembrane
domain by phenylalanine leads to hypoactivity of the receptor due to accelerated
desensitization and delayed resensitization. Thus, for the first time a link
between a human disease and a mutated neuronal nicotinic acetylcholine receptor
has been found, pointing to a possible involvement of this ligand-gated receptor
family in the modulation of brain excitability levels.
PMID- 9754875
TI - Multiple behavioral anomalies in GluR2 mutant mice exhibiting enhanced LTP.
AB - We have previously disrupted the ionotropic glutamate receptor type 2 gene
(GluR2) using gene targeting in embryonic stem cells and generated mice which
lacked the GluR2 gene product. Neurophysiological analyses of these mice showed a
markedly enhanced long-term potentiation (LTP) and a 9-fold increase in kainate
induced Ca2+ permeability in the hippocampus. Here, we analyze the behavioral and
neuroanatomical consequences of GluR2 deficiency in homozygous null mutant and
age-matched littermate control mice. We show that despite unaltered gross brain
morphology, several aspects of behavior were abnormal in the mutants. Object
exploration, rearing, grooming and locomotion were altered in the novel arena.
Eye-closure reflex, motor performance on the rotating rod and spatial and non
spatial learning performance in the water maze were also abnormal in the mutants.
These abnormalities together with the widespread expression pattern of GluR2 in
most excitatory CNS pathways suggest that the absence of GluR2 leads to
neurological phenotypes associated with not only the hippocampus but several
other brain regions potentially including the cortex and cerebellum. We speculate
that GluR2 mutant mice suffer from an overall non-specifically increased
excitability that may alter cognitive functions ranging from stimulus processing
to motivation and learning.
PMID- 9754876
TI - A 2-year longitudinal study of swimming navigation in mice devoid of the prion
protein: no evidence for neurological anomalies or spatial learning impairments.
AB - Uncontrolled accumulation of a conformationally distorted protein (PrP(Sc)) is
supposed to be the pathological process leading to spongiform encephalopathy.
Targeted disruptions of the Prn-P gene in the mouse have resulted in animals that
did not show anomalies in spatial and avoidance learning and were resistant to
experimental infections. However, another Prn-P knockout mouse was reported to
show ataxia and Purkinje cell degeneration developing after 70 weeks of age. In
this study the initial observations are confirmed on swimming navigation of PrP
null mutant mice using an enlarged sample of 58 mice. A representative subsample
of 16 mice was then followed up for their ability of swimming navigation up to an
age of two years (104 weeks). Surviving PrP-null mutants (n = 4) and controls (n
= 6) did not differ in any measure, nor were there indications of ataxia and
Purkinje cell degeneration. It was concluded that the PrP-knockout mice used by
Bueler et al. were probably normal with respect to aging processes and that
resistance to scrapie is not necessarily paid for by late neuronal degeneration.
The reasons for the discrepancy between different knockout experiments require
experimental clarification, however.
PMID- 9754877
TI - Transgenic mice expressing an alpha-secretion mutant of the amyloid precursor
protein in the brain develop a progressive CNS disorder.
AB - Expression of alpha-secretion mutant APP/RK in mouse brain results in a
progressive disorganization of the central nervous system, exemplified by
behavioral deficits, premature death and neuropathology. Here we report on the
progressive nature of this CNS disorder as indicated by the age dependency of the
neophobic reaction in the open-field test. The earlier reported NMDA hypo
sensitivity in the transgenic APP/RK mice is likely to represent a subtle
functional disturbance, since no changes in NMDA receptor density or distribution
could be detected. None of the typical neuropathological hallmarks of Alzheimer's
Disease, i.e. amyloid deposits and neurofibrillary tangles are detected in the
brain of these transgenic mice. Nevertheless, the progressive CNS disorder
elicited in the transgenic APP/RK mice recapitulates certain features and
symptoms of patients with Alzheimer's disease as discussed.
PMID- 9754879
TI - The genetic basis of the relation between speed-of-information-processing and IQ.
AB - The relationship of speed-of-information-processing (SIP), as derived from
reaction times (RTs) on experimental tasks, and intelligence has been extensively
studied. SIP is suggested to measure the efficiency with which subjects can
perform basic cognitive operations underlying a wide range of intellectual
abilities. Observed phenotypic correlations between RT and IQ typically are in
the -0.2 to -0.4 range, and the question is addressed to what extent this
relationship is determined by genetic or environmental influences. In a group of
Dutch twins the heritabilities for RT tasks at age 16 and 18 years were estimated
longitudinally and the nature of the RT-IQ relationship was investigated. At age
16 years heritabilities for a simple reaction time (SRT) and choice reaction time
(CRT) were 64 and 62% and the average phenotypic correlations between the RTs and
IQ, assessed by the Raven standard progressive matrices, was -0.21. At the second
test occasion lower heritabilities were observed for the RTs, probably due to
modifications in administration procedures. The mean correlations between the RTs
and WAIS verbal and per formal subtests were -0.18 and -0.16. Multivariate
genetic analyses at both ages showed that the RT-IQ correlations were explained
by genetic influences. These results are in agreement with earlier findings
(Baker et al., Behav Genet 1991;21:351-67; Ho et al., Behav Genet 1988;18:247-61)
and support the existence of a common, heritable biological basis underlying the
SIP-IQ relationship.
PMID- 9754878
TI - Neurobehavioral development, adult openfield exploration and swimming navigation
learning in mice with a modified beta-amyloid precursor protein gene.
AB - The processing of beta-amyloid precursor protein (betaAPP) and its metabolites
plays an important role in the pathogenesis of Alzheimer's disease (AD) and
Down's syndrome. The authors have reported elsewhere that a targeted mutation
resulting in low expression of a shortened betaAPP protein (betaAPP(delta/delta))
entails reduced learning abilities. Here the authors investigate whether these
effects were caused by postnatal developmental actions of the altered protein.
The authors examined 35 mice carrying the betaAPP(delta/delta) mutation for
somatic growth and sensorimotor development during the first 4 postnatal weeks
(pw) and compared them with 31 wildtype litter-mates. Thereafter, the same mice
were tested at about 10 weeks of age for openfield behavior and for swimming
navigation learning. Mutant mice showed both transient and long-lasting deficits
in development. Body weight deficit started to emerge at postnatal day (pd) 12,
peaked with a 15.1% deficit at pd 27 and lasted until pw 33-37. Significant
transient deficits in mutant mice during sensorimotor development were observed
in three time windows (pd 3-10, pd 11-19 and pd 20-27), long-lasting effects,
manifest at pw 8-12 and pw 33-37, emerged at any of the three periods. In the
adult mice, exploratory activity of betaAPP mutants in the openfield arena was
severely reduced. In the Morris water maze task, mutant mice showed moderate
escape performance deficits during the acquisition period but no impairment in
spatial memory. The authors conclude that a defective betaAPP gene impairs
postnatal somatic development, associated with transient as well as long-lasting
neurobehavioral retardation and muscular weakness. Comparison with earlier data
suggests that early postnatal handling may attenuate some of the non-cognitive
performance deficits in the water maze. Further, the manifestation and time
course of behavioral yet not neuropathological symptoms in betaAPP mutant mice
resemble in some aspects those of the human Down's syndrome.
PMID- 9754880
TI - Posterior parietal cortex lesions severely disrupt spatial learning in DBA mice
characterized by a genetic hippocampal dysfunction.
AB - C57BL/6 (C57) and DBA/2 (DBA) inbred mice with posterior parietal cortex or sham
lesions were tested in a radial eight-arm maze task with all the paths baited. In
the high learner C57 strain, parietal lesions produced a limited impairment of
performance without affecting maze-running strategies while the same lesions were
found to affect more severely performance in the poor learner DBA strain. Because
(1) the processing of spatial information has been found to depend on the
conjunctive participation of the hippocampus and the posterior parietal cortex,
and (2) DBA mice represent a genetic model of hippocampal dysfunction, the fact
that parietal lesions impair spatial performance more severely in the DBA strain
suggests that the contribution of the posterior parietal cortex to spatial
learning depends on the degree of functionality of the hippocampus.
PMID- 9754881
TI - A new continuous alternation task in T-maze detects hippocampal dysfunction in
mice. A strain comparison and lesion study.
AB - The mammalian hippocampus has been the focus of several neurobiology studies
because of its important behavioral function and because long-term potentiation
(LTP) is a prominent feature of this brain region. Converging evidence suggests
that hippocampal function is associated with learning multiple relationships of
environmental cues. In this paper a novel behavioral test procedure is
introduced, a modified T-maze continuous alternation task (T-CAT), that may serve
as a simple, automatable, and quick test of hippocampal function in addition to
the frequently applied water maze and fear conditioning paradigms. A comparison
is made between mice (strain C57BL/6) with ibotenic acid lesioned or vehicle
injected hippocampus, two transgenic strains (on CD1 background) overexpressing a
calcium binding protein, S100beta, and inbred (C57BL/6, DBA/2, 129/SV and
129/SVEV) and outbred (CD1) strains of mice. This study shows that hippocampal
lesioning led to a significant impairment in T-CAT. Furthermore, overexpression
of S100beta, which impairs hippocampal LTP, also led to an impairment
demonstrating that T-CAT is sensitive to detect hippocampal dysfunction. Analysis
of the mouse strains revealed that C57BL/6 and CD1 mice performed well in T-CAT,
whereas 129/SV, 129/SVEV and DBA/2 were significantly impaired, a finding that
underscores the importance of strain differences in pharmacological or single
gene manipulation studies of hippocampal function in mice.
PMID- 9754882
TI - D1 dopamine receptors and the reversal of isolation-induced behaviors in mice.
AB - In a previous study, it was demonstrated that the high rates of social reactivity
exhibited by isolated male mice in a dyadic encounter were mediated, at least in
part, by an increased sensitivity of the D1 dopamine receptors. The present
research was guided by the hypothesis that the behavioral effects of isolation
are reversible, and that changes in dopaminergic function support this
reversibility. To this end, mice selectively bred for high and low levels of
aggression were reared in isolation from weaning (21 days) to puberty (45 days),
at which point they were either assigned to groups or left in isolation until day
69. By comparison to the continuous isolation condition, mice that eventually
formed groups exhibited significantly less reactivity in a dyadic test conducted
on day 69, showed a reduced response to dihydrexidine (DHX), and a decreased
density of D1 dopamine receptors. This experiment provided evidence for the
plasticity of the neurobiological system supporting reactive responses, and
confirmed the view that its functional organization is open to experientially
induced changes.
PMID- 9754883
TI - Drug withdrawal convulsions and susceptibility to convulsants after short-term
selective breeding for acute ethanol withdrawal.
AB - High Alcohol Withdrawal (HAW) and Low Alcohol Withdrawal (LAW) mice were
selectively bred from a foundation population of C57BL6/J (B6) x DBA/2J (D2) F2
intercross progeny for display of intense or mild handling-induced withdrawal
convulsions, respectively, following a single injection of a hypnotic dose of
ethanol (alcohol; 4 g/kg). The HAW line had significantly greater alcohol
withdrawal severity scores compared to the LAW line after only a single
generation of selection; the magnitude of the line difference was 8-fold by the
fourth selected generation. We tested these lines for severity of withdrawal
convulsions following the benzodiazepine, diazepam; the gaseous anesthetic,
nitrous oxide; the imidazopyridine, zolpidem and the barbiturate, pentobarbital.
In all cases, HAW mice had significantly greater withdrawal severity than mice of
the LAW line. These results indicate that some genes influencing withdrawal
convulsion severity following ethanol also affect withdrawal from other CNS
depressants. D2 mice are more sensitive to a variety of convulsants than B6 mice
(and have more severe withdrawal convulsions). We, therefore, tested separate
groups of mice of both selectively bred lines for threshold sensitivity to
pentylenetetrazol (PTZ), N-methyl-D-aspartate (NMDA) and kainic acid (KA). No
line differences were detected. These results indicate that genes influencing
severity of withdrawal from several depressant drugs are largely different from
those affecting susceptibility to GABAergic or glutamatergic convulsants.
PMID- 9754884
TI - Non-selective attention and nitric oxide in putative animal models of Attention
Deficit Hyperactivity Disorder.
AB - Non-selective attention (NSA) to environmental stimuli has been measured in
putative animal models of Attention-Deficit Hyperactivity Disorder (ADHD), such
as the Spontaneously Hypertensive (SHR) and the Naples High-Excitability (NHE)
rat lines. A series of experiments has been carried out on male juvenile SHR and
Wistar-Kyoto (WKY) controls (experiment 1) and on the NHE and two controls, i.e.
the Naples Low-Excitability (NLE) and a random-bred (NRB) line (experiment 2). It
was done under basal conditions or following a single injection of the nitric
oxide synthase (NOS) inhibitor L-nitro-arginine-methylester (L-NAME: 0.1-10
mg/kg, i.p.), or vehicle, 30 min before testing on day 1 and vehicle alone before
testing on days 2 and 3 in SHR/WKY (experiment 3) and the Naples lines
(experiment 4). The behavior in a Lat maze during three consecutive 10-min
exposures at 24-h intervals was monitored by a CCD video camera and analyzed off
line for frequency and duration of rearings on hindlimbs per 1-min blocks. The
results demonstrated that both SHR and NHE rats showed a higher frequency of
rearings of shorter duration than controls. With time of testing, the duration of
rearings tended to increase in the WKY but not the SHR. In the Naples lines the
duration tended to increase in all but mostly in the NHE rats. The acute
inhibition of NOS by L-NAME significantly increased the duration of rearing
episodes both in SHR and NHE rats only at 10 mg/kg in the second part of the
testing period. Therefore, NSA, as indexed by the duration of rearings, is
defective in both hyperactivity models against different genetic backgrounds. In
addition, this impairment is dependent upon nitric oxide (NO), which appears to
play a significant role in these processes.
PMID- 9754885
TI - Neuronal and behavioral differences between Mus musculus domesticus (C57BL/6JBy)
and Mus musculus castaneus (CAST/Ei).
AB - Previous studies have demonstrated that classical inbred strains of laboratory
mice do not exhibit large genetic distances when simple sequence repeats (SSRs)
are used to test for their polymorphisms whereas mice from wild origin exhibit
high polymorphisms (more than 90%) for these sequence when compared with
classical inbred strains of laboratory mice. The difference between Mus musculus
castaneus and C57BL/6J reaches 98% and F1s male and female are fertile. These two
properties pave the way for gene mapping derivating segregating generations
between these strains. The phenotypical characteristics of Mus musculus castaneus
have not been investigated, unfortunately. The first screening of Mus musculus
castaneus and C57BL/6By was carried out for sensorial and motor development,
spontaneous behavior in new environment, paw preference, maternal behavior,
aggression in two different situations and time to learn escape in a water maze.
Morphometry of hippocampus and weight of the male reproductive organs for
measures that have been reported to be correlated with several of the examined
behavior are also reported. The authors tested also reactivity to one drug (beta
CCM) revealing seizure proneness. The two strains differ for 69% of the reported
measures. Comparison to other strains for the same measures obtained in the
laboratory for identical tests with mice reared in identical situations provided
the mean to compare Mus musculus castaneus with a large set of more or less
traditional mice. This strain has the most extreme position for 80% of the
comparisons.
PMID- 9754886
TI - The role of non-nucleoside reverse transcriptase inhibitors (NNRTIs) in the
therapy of HIV-1 infection.
AB - Non-nucleoside reverse transcriptase inhibitors (NNRTIs) have, in addition to the
nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitors
(PIs), gained a definitive place in the treatment of HIV-1 infections. Starting
from the HEPT and TIBO derivatives, more than 30 structurally different classes
of compounds have been identified as NNRTIs, that is compounds that are
specifically inhibitory to HIV-1 replication and targeted at the HIV-1 reverse
transcriptase (RT). Two NNRTIs (nevirapine and delavirdine) have been formally
licensed for clinical use and several others are in preclinical or clinical
development [thiocarboxanilide UC-781, HEPT derivative MKC-442, quinoxaline HBY
097 and DMP 266 (efavirenz)]. The NNRTIs interact with a specific 'pocket' site
of HIV-1 RT that is closely associated with, but distinct from, the NRTI binding
site. NNRTIs are notorious for rapidly eliciting resistance due to mutations of
the amino acids surrounding the NNRTI-binding site. However, the emergence of
resistant HIV strains can be circumvented if the NNRTIs, alone or in combination,
are used from the start at sufficiently high concentrations. In vitro, this
procedure has proved to 'knock-out' virus replication and to prevent resistance
from arising. In vivo, various triple-drug combinations of NNRTIs (nevirapine,
delavirdine or efavirenz) with NRTIs (AZT, 3TC, ddI or d4T) and/or PIs (indinavir
or nelfinavir) have been shown to afford a durable anti-HIV activity, as
reflected by both a decrease in plasma HIV-1 RNA levels and increased CD4 T
lymphocyte counts.
PMID- 9754887
TI - Cartesian coordinate analysis of viral burden and CD4+ T-cell count in human
immunodeficiency virus type-1 infection.
AB - We have used a Cartesian coordinate plot to analyze the inverse relationship
between viral burden (x-axis) and peripheral blood CD4+ cell count (y-axis) to
extend our understanding of the mechanisms of antiviral drugs and differences in
outcome resulting from variability in virus and host responses. Each of 186
subjects studied were assigned to one of four response quadrants. Quadrants A (x
, y+) and D (x+, y-) defined the effect of a change in virus load on the inverse
change in CD4+ cell count expected from the natural history of HIV infection or
antiretroviral therapy. Quadrants B (x+, y+) and C (x-, y-) defined the
dissociation of the inverse relationship between the relative changes in CD4+
cell count and viral load that resulted from the hypothesized effect of putative
virologic or immunologic response modifiers. Of the response modifiers studied,
only the syncytium-inducing phenotype resulted in a complete dissociation of this
inverse relationship. The analysis provided an integrated virological and
immunological approach to better understand therapeutic responses and potential
dissociation between changes in viral RNA and CD4+ cell count. This type of
analysis may be helpful for individualizing patient management as well as
designing and analyzing studies of HIV-1 antiretroviral drugs and disease
pathogenesis.
PMID- 9754888
TI - Interferon-alpha inhibits the emergence of cellular stress response-dependent
morbillivirus large plaque variants.
AB - Cellular levels of heat shock proteins (HSPs) are elevated in response to
physiologic states accompanying acute virus infection (e.g. fever). The objective
of the present work was to define the antiviral effect of purified human
lymphoblastoid IFN in the presence of HSP over-expression. For this purpose,
canine distemper virus (CDV) was used since the response of CDV transcription and
persistent infection phenotype to elevated HSP is characterized. First, the
effect of elevated HSP on CDV lytic infection phenotype in Vero and CV1 cells was
defined, and results extended to the closely related measles virus (MV). Cells
expressing elevated levels of the major inducible 70-kDa HSP (hsp72) supported
the emergence of large plaque variants of both CDV and MV from small plaque
purified inocula. IFN treatment concurrent with infection caused a dosage
dependent reduction in the expression of large plaque variants without affecting
hsp72 levels or total plaque number. In contrast to the stress response-induced
large plaque variant, small plaques were resistant to the antiviral effects of
IFN. These data demonstrate the ability of IFN to selectively abrogate the pro
viral effects of HSP over-expression, inhibiting the formation of a plaque
phenotype that is correlated to enhanced virulence in animal models of
morbillivirus encephalitis.
PMID- 9754889
TI - The effect of increasing gastric pH upon the bioavailability of orally
administered foscarnet.
AB - For systemic use, the anti-cytomegalovirus (CMV) agent foscarnet must be given
intravenously because oral administration results in unmeasurable or barely
measurable plasma levels. At low pH, foscarnet decomposes via an acid-catalyzed
decarboxylation; therefore, poor oral bioavailability might be due to
decomposition of foscarnet in gastric acid. We evaluated whether increasing
gastric pH with ranitidine would enhance the absorption of oral foscarnet in six
asymptomatic HIV-infected individuals. Each volunteer received two oral 4000-mg
(60 mg/kg) doses of foscarnet, preceded intravenously by a 20-min infusion of
either ranitidine 50 mg in D5W or D5W alone in a randomized, double-blind, cross
over study. Intragastric pH monitoring revealed that subjects had evidence of
gastric acid production (pH < 2.0) prior to administration of ranitidine and
increased gastric pH (pH > 6.0) following ranitidine administration. Most
foscarnet plasma levels were below the assay limit of detection (33 microM) with
only 4/30 levels detectable after D5W and 8/30 after ranitidine. Urinary recovery
of foscarnet increased after ranitidine pretreatment. A mean recovery of 9.9% of
the drug was realized in the urine in 24 h following ranitidine pretreatment
compared to 6.2% of the dose after D5W pretreatment (P < 0.03). We estimate that
9.9% recovery in the urine in 24 h is equivalent to absorption of 17.1% of the
oral dose. In spite of the enhanced bioavailability associated with ranitidine
pretreatment, the degree of absorption is still insufficient to achieve effective
plasma concentrations for the treatment of CMV or acyclovir-resistant herpes
viruses. We conclude that gastric acidity is a determinant of foscarnet
absorption, albeit not a major one. Oral foscarnet is unlikely to be clinically
useful even if administered in the setting of increased gastric pH.
PMID- 9754890
TI - Long-term stability of the anti-influenza A compounds--amantadine and
rimantadine.
AB - Amantadine and rimantadine hydrochloride were tested for stability after storage
at different temperatures and under different conditions for extended periods of
time. Both compounds were quite stable after storage for at least 25 years at
ambient temperature; they both retained full antiviral activity after long-term
storage or after boiling and holding at 65-85 degrees C for several days. Thus,
amantadine and rimantadine could be synthesized in large quantities and stored
for at least one generation without loss of activity in preparation for the next
influenza A pandemic in humans.
PMID- 9754891
TI - Staged basilic vein transposition for dialysis angioaccess.
AB - BACKGROUND: To find out a suitable procedure to dissect an arterialised thick
walled vein to create secondary angioaccess for dialysis. Delicacy of the vein
wall, high rate of thrombosis and difficulty to find out a suitable vein are the
main obstacles to vascular surgeons during the creation of secondary angioaccess.
METHODS: Forty patients in need for secondary angioaccess for dialysis were
admitted for basilic vein transposition. They were classified randomly into two
equal groups matched for age and sex. Group A patients were submitted to
traditional basilic vein transposition. In group B, the operation was done in two
stages. In the first stage, brachiobasilic anastomosis was done. Two to four
weeks later the second stage was done to 19 patients (one patient had occluded
shunt before the second stage) in the form of superficialization of the vein to
be placed in the subcutaneous tissue. RESULTS: Follow-up period for 6-24 months
revealed that in the early postoperative period (4 weeks after operation) patency
rate was 12/20 (60%) in group A and 18/20 (90%) with significant difference
(p<0.05) between the two groups. Later, occlusion occurred in two patients in
each group. At the end of the study the overall patency was 10/20 (50%) and 16/20
(80%) in group A and B respectively with significant difference between them.
Both groups were similar in minor complications. CONCLUSIONS: The staged basilic
vein transposition is superior to the traditional operation in the patency rate
and is recommended as a safe operation for a successful secondary angioaccess.
PMID- 9754892
TI - Clinical evaluation of new global clotting assay for monitoring of LMWH
treatment: pilot study.
AB - Until now, there has been no reliable method for the monitoring low molecular
weight heparin (LMWH) therapy. Based on our observations of the coagulant
activity of pseudoserum obtained after clotting of recalcified plasma from
patients who were treated with LMWH, we were led to develop a new global clotting
assay for the monitoring of this treatment. Methods description. After performing
Howell time on PPP, samples were incubated for 30 min in 37 degrees C and they
were then centrifuged for 10 min 0.2 ml of this pseudoserum is added to 0.2 ml of
citrated normal plasma. Pseudoserum triggered coagulation of normal plasma and
the time of new clot formation is expressed in seconds. This assay was called
ATHU-test (AHEPA Thromb Haem Unit). We tested 21 normal subjects a in order to
define the normal mean value and the range of the method. b) We also checked the
reproducibility of the method by repeating the ATHU-test 17 times on the same
normal plasma. c) We performed in vitro experiments to study its reliability and
we added increasing concentrations using given doses of enoxaparine (4, 8, 12, 16
mg/ml) or fraxiparine (1.5, 3.0, 4.5, 6 u aXa/ml) which was added in vitro to
normal plasma confirming the proportional linear regression between duration of
our test and the amount of LMWH. Finally d) we checked on the therapy response
and the LMWH levels in blood for thrombophiliacs. Results. a) NP, n=21, X=138.6+/
41.1, range 75-225 sec which means that values >X+/-3S=261.9 are distinctively
pathological. b) The reproducibility of the method is acceptable, CV=9%. c) It is
confirmed that in vitro addition of precautionary doses of LMWH (1.5 u aXa/ml)
exceeds the coagulation time of ATHU-test up to 300 sec and it follows a
distinctively proportional relationship. d) The monitoring of 20 thrombophiliacs
for 2 months proved that: i) All their test times were between 4-15 min. The more
we approach the value of 15 min the more danger there is of haemorrhage while, on
the contrary, the more values approach 4 min the more the danger of rethrombosis
increases. We present the ATHU-test, a simple test which has been used for 6
months now by our Unit, in order to control the LMWH therapy for patients with
thromboembolic diseases. The ATHU-test's reproducibility and its small range of
normal values, the distinct relationship between therapeutic doses and
therapeutic clinical results, as well as the in vitro proof of the linear
regression between the coagulation time and the containing amount of LMWH, are
likely to establish a new method of choice for the monitoring of LMWH therapy.
PMID- 9754893
TI - Color duplex sonography guided stent placement in a stenosis of the superficial
femoral artery. A case report.
AB - We report the first case of a successful stent placement under color coded
ultrasound guidance alone in the superficial femoral artery of a 73-year-old
woman suffering from intermittent calf claudication following restenosis after an
uncomplicated angioplasty five months previously. Because of a hemodynamically
residual stenosis after three attempts at dilatation, a percutaneous transluminal
angioplasty and stent insertion were performed under the sole guidance of color
coded ultrasound. The intervention was performed without complication and at the
six-month follow-up examination, the patient was symptom-free and the stent was
morphologically intact and hemodynamically functional. This case shows that
successful stent placement under ultrasonic guidance alone, without fluoroscopic
control is possible, provided that there is adequate sonographic visualization.
PMID- 9754894
TI - How "gold" is the standard? Interobservers' variation on venograms.
AB - BACKGROUND: The aim of this study was to determine the degree of agreement
between radiologists having different levels of experience, in reporting 151
venograms independently. It was also aimed to assess whether the degree of
disagreement would have influenced the final outcome of a thromboprophylactic
study and the decision to anticoagulate the patients. METHODS: Seventy-eight
patients undergoing total hip replacement had bilateral venography on
postoperative days 8-12. Patients were allocated to receive either a low
molecular weight heparin (enoxaparin) with or without TED stockings or a placebo
Each of the 151 venograms obtained has been reported on four times. RESULTS: The
overall incidence of deep venous thrombosis was 42% (33 of 78 patients). The
range of the Kappa value of each radiologist versus the others was 0.568 to
0.669. There was a significant decrease in the incidence of deep venous
thrombosis in the treatment versus the placebo groups. On an intention to treat
all diagnosed thrombi, a difference of up to 16% was demonstrated between the
report of individual radiologists and the panel. This difference was reduced to
8% when only thrombi proximal to the calf were considered clinically significant.
CONCLUSIONS: These differences reflect the radiologist's experience and frequency
of reporting on venograms and should be taken into account when studies for
thromboprophylaxis are planned.
PMID- 9754895
TI - Restricted usage of T-cell receptor Valpha-Vbeta genes in infiltrating cells in
the aortic tissue of a patient with atherosclerotic aortic aneurysm.
AB - We report a rare case of an atherosclerotic aortic aneurysm with lymphocyte
infiltration in which T-cell receptor (TCR) Valpha as well as Vbeta gene usage
was restricted. Immunohistochemical studies showed that the infiltrating cells
mainly consisted of macrophages, natural killer (NK) cells, cytotoxic T
lymphocytes (CTLs) and T-helper (Th) cells, and that there were almost no
infiltrating delta T lymphocytes, and human leukocyte antigen (HLA) class I and
65-kD heat-shock protein (HSP-65) was not strongly expressed in the aortic
tissue. Although the immunohistochemical data were consistent with an ordinary
atherosclerotic aortic aneurysm, in which TCR Valpha-Vbeta gene usage is known to
be polyclonal, the restricted TCR gene usage suggests that a certain autoimmune
mechanism was involved in the pathogenesis of this case similar to Takayasu's
arteritis, in which massive infiltration of delta T lymphocytes and strong
expression of HSP-65 in the aortic tissue are characteristic.
PMID- 9754896
TI - Prevention of deep vein thrombosis in knee arthroplasty. Preliminary results from
a randomized controlled study of low molecular weight heparin vs foot pump
compression.
AB - BACKGROUND: We evaluated in a randomized controlled study the possibility to use
foot pump mechanical compression compared to routine LMWH as prophylaxis against
deep vein thrombosis during knee arthroplasty. METHODS: Forty patients were
included in this preliminary report. Eleven patients withdrew, usually during the
early phase of the study. RESULTS: Among the 29 patients completing a venography,
27% in the compression group and none in the LMWH group had a DVT. This
difference was statistically significant (p<0.05). One further patient in the
compression group died from pulmonary embolism 17 days postoperatively.
CONCLUSIONS: With the present study protocol, mechanical foot pump compression
failed to be as efficient as LMWH prophylaxis.
PMID- 9754897
TI - Plasma endothelin-1 concentrations in non-insulin-dependent diabetes mellitus and
nondiabetic patients with chronic arterial obstructive disease of the lower
limbs.
AB - BACKGROUND: Endothelin-1 (ET-1), a vasoconstrictor and mitogenic endothelium
derived peptide, has been considered as a marker for endothelial damage and
potential contributor to the development of the atherogenic process. METHODS: To
evaluate the pattern of plasma ET-1 secretion in non-insulin-dependent diabetes
mellitus (NIDDM) and nondiabetic patients with chronic arterial obstructive
disease (CAOD) of the lower limbs, plasma levels of ET-1 were determined in 12
NIDDM patients (10 men and 2 women; mean age 63+/-8 years) with CAOD of the lower
limbs at Fontaine stage II and in 12 nondiabetic patients (11 men and 1 woman;
mean age 62+/-4 years) with comparable arteriopathy. Ten normal subjects
comprised the control population. RESULTS: The plasma levels of ET-1 in NIDDM
patients with CAOD of the lower limbs were 5.7+/-0.3 pmol/L, which represented a
significant (p<0.001) difference from the values in nondiabetic patients with
comparable arteriopathy (4.1+/-0.6 pmol/L) and those in the control group (2.7+/
0.7 pmol/L). Plasma levels of ET-1 showed a significant (p<0.0001) positive
correlation with the levels of fasting insulin in NIDDM patients with CAOD of the
lower limbs. Increased plasma ET-1 could reflect a major and/or more diffuse
endothelial cell damage or dysfunction in NIDDM than in nondiabetic patients with
comparable CAOD of the lower limbs. Augmented mitogenic ET-1 levels could also
have a role both in diabetic and nondiabetic angiopathy. CONCLUSIONS: The
positive correlation between ET-1 plasma levels and fasting insulin levels in
NIDDM patients with CAOD of the lower limbs suggests that the increased ET-1
release could be related to the augmented insulin secretion in these patients.
Insulin-related overproduction of ET-1 could promote the atherogenic process and
enhance the vascular tone to a greater extent in NIDDM than in nondiabetic
patients with CAOD of the lower limbs.
PMID- 9754898
TI - Duplex sonography of vascularization of venous thrombosis.
AB - BACKGROUND: Changes in the echogenicity of an ageing intravenous thrombus have
already been described in B-mode sonography. We tried to investigate the
phenomena of vascularisation of the intravenous thrombotic material during the
organisation using colour Doppler sonography. METHODS: We carried out a
prospective investigation of 8 jugular vein, 6 femoral vein and 1 inferior caval
vein thrombosis. The thromboses were investigated with a colour Doppler
sonographic device from Siemens, type Elegra, every second or third day for 4
weeks after making the diagnosis. We looked for intrathrombotic colour Doppler
signals with an arterial pulsatile blood flow in the pulsed Doppler mode.
RESULTS: We found arterial signals in the intravenous thrombus in 8 of the 15
patients. Such arterial Doppler signals were supposed to be arterial vessels
which develop during the organisation of the thrombotic material. The arterial
vessels appeared only in a short range of time from the 11th to the 25th day and
were present in circumscribed areas of the thrombus. Arterial blood vessels in
the surrounding tissue of the veins which may supply blood to the intrathrombotic
vessels could not be demonstrated. CONCLUSIONS: Thus the intravenous
documentation of arterial vessels in an organising intravenous thrombus is
possible. This may give information about the mechanism of thrombogenesis and
about the degree of organisation and may also help in determining the age of the
thrombosis.
PMID- 9754899
TI - Venous ulcers in chronic venous insufficiency: King Khalid University Hospital
experience.
AB - BACKGROUND: The purpose of this study was to identify the anatomical location of
the venous disease in C.V.I. patients presented with venous ulcers in addition to
discussing the management. DESIGN: Retrospective study, at King Khalid University
Hospital. METHODS: Between January 1991 to January 1997, 90 patients (63 females,
27 males) with CVI were evaluated. The evaluation included history, clinical
examination, bidirectional ultrasound continuous wave Doppler, Duplex, ambulatory
venous pressure (AVP), ascending and descending venography. RESULTS: Forty eight
(48) patients (57 limbs) had Stage III with venous ulcers. Out of these 48
patients, fifteen (15) showed deep venous system involvement with deep vein
thrombosis (DVT). Thirty three (33) patients had venous reflux in the superficial
or deep systems without occlusion. Out of these 33 patients, 24 patients had
superficial system reflux, while the remaining 9 patients revealed deep system
reflux with a competent superficial system. CONCLUSIONS: Superficial venous
incompetence plays a major role in venous ulcer formation and that location and
type of venous disease should be thoroughly investigated as surgical excision of
the superficial system leads to a long standing recurrence free period.
PMID- 9754900
TI - Aneurysm induced by periarterial application of elastase heals spontaneously.
AB - BACKGROUND: The pathogenesis of aortic aneurysms remains largely unknown, despite
aneurysmal rupture being an increasingly common catastrophe. METHODS: This study
was designed to elucidate the mechanism of arterial dilatation histologically and
electron microscopically, utilising a new animal model. Elastase, 3.0 mg/ml, was
applied to the abdominal aortae of 18 New Zealand white rabbits from the
adventitia side for 3 hours. The rabbits were sacrificed at 0, 3, 14, 28, 42 and
90 days after the procedure (n=4, 3, 2, 2, 2, 3). RESULTS: Two rabbits were found
to have developed aortic rupture. On day 0, elastase application induced fusiform
aneurysms up to 1.62+/-0.14 times the pre-elastase application aortic diameter.
Dilated walls revealed medial elastolysis, degeneration of smooth muscle cells
(SMCs) and damaged endothelial cells. By day 3, the smooth muscle cells had
changed to the synthetic type. Aneurysms did not progress, and after 42 days,
showed gradual shrinkage. By day 90, aortic diameters had nearly normalised.
CONCLUSIONS: Aortic walls also returned to the pre-elastase application thickness
and some mature medial elastic lamellae showed regeneration. Medial smooth muscle
cells reverted to the contractile type. Aortic dilatation induced by peri-aortic
application of elastase heals spontaneously, accompanied by regeneration of
smooth muscle cells. Irreversible degeneration of medial smooth muscle cells
appears to be more critical to aneurysm formation than degeneration of elastic
lamellae.
PMID- 9754901
TI - The white blood cell and plasma fibrinogen in thrombotic stroke. A significant
correlation.
AB - OBJECTIVES: Thrombotic stroke is a common disorder with considerable mortality
and morbidity. Risk factors for stroke include cigarette smoking, hypertension
and hyperlipidaemia and these have been linked to abnormalities of haemorrheology
and coagulation such as increased fibrinogen. Other haemorrheological
abnormalities have also been documented. These include an elevation in the white
blood cell (WBC) count. The aim of our study was to evaluate plasma fibrinogen,
WBC aggregation and the release of free radicals in thrombotic stroke.
EXPERIMENTAL DESIGN: Thirty-four patients with thrombotic stroke were enrolled in
the study. The data were compared to 58 matched controls. SETTING: This study was
carried out in Ninewells Hospital, Dundee on patients previously admitted to the
medical wards with acute stroke. MEASURES: Plasma fibrinogen, WBC aggregation and
plasma malondialdehyde (MDA) were measured in this study. RESULTS: As expected,
the stroke patients have a significantly higher fibrinogen level (4.3+/-1.2 g/dl
versus 3.1+/-0.6, p<0.001). WBC aggregation is also increased in the patient
group (47.5+/-10.4% versus 42.7+/-10.6, p=0.036), as is plasma MDA (8.6+/-2.0
micromol/l versus 7.1+/-1.07, p<0.001). The factor VIII von Willebrand factor
antigen measured as a marker as vascular damage was also significantly higher in
the patient group (251+/-87% versus 182+/-64, p<0.001). There was also a
statistically significant correlation between fibrinogen level and WBC
aggregation, and fibrinogen and MDA. These are both statistically significant
p=0.012 and p<0.001 respectively. CONCLUSIONS: We believe our study suggests that
enhanced WBC aggregation/adhesion with release of free radicals may be another
mechanism whereby fibrinogen exerts its known detrimental effect in stroke
development. This may allow planning of therapeutic strategies as yet
undeveloped.
PMID- 9754902
TI - Surgical treatment of spontaneous internal carotid dissection.
AB - Spontaneous dissection of the internal carotid artery is rarely submitted to
surgery. We report a case successfully operated on with complete restoration of
the cerebral blood flow. A 43-year-old male was admitted to our hospital 10 days
after an episode of amaurosis fugax of the left eye, left sided headache and
paresis of the right arm of a few hours duration. A diagnosis of dissection of
the left internal carotid artery was made by duplex and triplex ultrasound
examination and was confirmed by cerebral arteriography in contrast to magnetic
resonance angiography which was misleading. Due to the slow arterial flow from
the right to the left cerebral hemisphere through only the posterior
communicating arteries we envisaged the possibility of a cerebral infarction if
the dissection were to be extended. For this reason a surgical procedure was
performed by excising the dissected segment and inserting a venous graft for the
re-establishment of the arterial flow. Surgical treatment of spontaneous internal
carotid dissection should be considered very carefully when the clinical and
laboratory findings suggest the possibility of an impending stroke.
PMID- 9754903
TI - Microglial and astrocytic involvement in a murine model of Parkinson's disease
induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).
AB - We have studied the reaction of glial cells in mice treated with an
intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
(MPTP), a selective neurotoxin of dopaminergic nigrostriatal neurons. Signs of
injury to the dopaminergic neurons started on the 1st day after MPTP
administration and progressed up to the end of the observation time (21st day). A
transient microglial reaction was demonstrated from the 1st until the 14th day in
the substantia nigra (SN) and striatum. The cells showed an increase in number
and changes in morphology. At the ultrastructural level, signs of phagocytosis
and features indicating the secretion of biologically active substances were
observed. Astrocytosis followed the microglial reaction by one day and was
noticed until the end of the observation time. Interleukin-6 immunoreactivity was
observed within microglia and astrocytes in the SN on days 2 and 3. There were no
signs of depletion of dopaminergic cells or glial activation after the
administration of MPTP simultaneously with pargyline, an inhibitor of monoamine
oxidase-B that prevents MPTP neurotoxicity. Our study indicates that microglia
and astrocytes are involved in the pathological process in the nigrostriatal
system following MPTP administration. MPTP alone is not responsible for glial
cell activation but its metabolite MPP+ and/or agents released by injured neurons
may participate in this process.
PMID- 9754904
TI - The inhibitory effect of ursodeoxycholic acid and pentoxifylline on platelet
derived growth factor-stimulated proliferation is distinct from an effect by
cyclic AMP.
AB - This study assessed the ability of ursodeoxycholic acid (UDCA) and one of its
metabolites, tauroursodeoxycholic acid (TUDCA), to inhibit platelet derived
growth factor (PDGF) stimulated fibroproliferation and compared these results to
the effect of pentoxifylline and its metabolite-1 [1-(5-hydroxyhexyl)-3,7
dimethylxanthine] and assessed the potential role of cyclic AMP in this process.
Fibroproliferative activity was measured by the tritiated thymidine uptake assay
in human fibroblast cultures. All four compounds: pentoxifylline, metabolite-1,
UDCA and TUDCA inhibited the fibroproliferative activity stimulated by PDGF (8
ng/ml). Incubation of fibroblasts with dibutyryl cyclic AMP reduced proliferation
stimulated by PDGF suggesting that the PDGF stimulated proliferation was
sensitive to inhibition by a membrane permeable analogue of cyclic AMP.
Incubation of myofibroblasts with dibutyryl cyclic AMP significantly inhibited
PDGF stimulated proliferation suggesting that cyclic AMP can regulate PDGF
stimulated proliferation in the myofibroblast. To determine if the effect of
pentoxifylline on fibroproliferation was mediated by cyclic AMP, we used
dideoxyadenosine, a potent inhibitor of adenylyl cyclase. The effect of
pentoxifylline on fibroproliferation was not prevented by dideoxyadenosine, which
inhibits formation of cyclic AMP, thus suggesting that the inhibitory effect of
pentoxifylline on PDGF-stimulated proliferation of fibroblasts was not mediated
by cyclic AMP, arguing against a role for cyclic AMP in this process.
Combinations of UDCA (250 microM) plus pentoxifylline (120 microM) or UDCA (250
microM) plus TUDCA (250 microM) inhibited fibroproliferative activity stimulated
by PDGF to a greater extent than either drug alone. As UDCA has been reported to
decrease cyclic AMP these results argue against a role for cyclic AMP in this
process. Finally the results suggest that UDCA may inhibit PDGF-stimulated
proliferation via an inhibition of C-kinase.
PMID- 9754905
TI - The effect of fluticasone propionate on respiratory syncytial virus-induced
chemokine release by a human bronchial epithelial cell line.
AB - Respiratory syncytial virus (RSV) is an important cause of bronchiolitis in
infants, is an important trigger of asthma exacerbation, and stimulates chemokine
production by human respiratory epithelial cells in vitro. We tested the effect
of the corticosteroid fluticasone propionate (FP) on RSV-stimulated production of
the chemokines interleukin 8 (IL-8) and RANTES (regulated upon activation, normal
T cell expressed and secreted) by a human bronchial epithelial cell line, BEAS
2B. Confluent BEAS-2B cultures were inoculated with RSV at approximately 1 plaque
forming unit/cell, and media were collected at 24 h intervals. Concentrations of
IL-8 and RANTES were measured in supernatants using ELISA. The effect of FP at
varying concentrations on RSV-induced chemokine release was determined. RSV
stimulated increased release of both IL-8 and RANTES, particularly at 24-48 h
after virus inoculation. Significant but incomplete inhibition of RSV-stimulated
increases for both chemokines was found when cultures were treated with FP at >
or = 10(-8) M (for IL-8) or > or = 10(-7) M (for RANTES). There was no
significant effect of FP on release of RSV itself from infected BEAS-2B cells. We
conclude that a possible mechanism for the efficacy of inhaled corticosteroids in
reducing the frequency or severity of asthma exacerbations is inhibition of virus
induced chemokine production by airway cells.
PMID- 9754906
TI - Effects of 2-deoxy-D-glucose administration on immune parameters in mice.
AB - Physical exercise and diet alterations have been shown to affect immune
parameters. Similar effects are also induced by the administration of the non
metabolizable glucose analog, 2-deoxy-D-glucose (2-DG). The current study was
designed to characterize the effects of glucoprivation induced by 2-DG
administration on leukocyte subset distribution and function. BDF1 mice (n = 8
per group) were injected intraperitoneally one or three times with 0, 500, 750,
1000 or 1500 mg/kg of 2-DG. Two hours after the last injection of 2-DG,
immunological parameters were analyzed. A dose-dependent increase in plasma
glucose concentrations of mice injected once with up to 1500 mg/kg of 2-DG was
observed (p < 0.001). After either one or three injections of up to 1500 mg/kg of
2-DG, corticosterone levels, leukocyte counts in the spleen, and CD3+ cells in
the thymus increased. In vitro proliferation of partially purified lymphocytes
from the spleen in the presence of both concanavalin-A and lipopolysaccharide
decreased in a dose dependent manner (p < 0.05). In addition, after three
injections, the proportion of both thymocytes and splenocytes bearing alphabeta
TCR increased as the concentration of 2-DG increased (p < 0.01). These results
demonstrate that 2-DG administration induced dose-dependent changes in both
thymus and spleen cell distribution and function.
PMID- 9754907
TI - Effect of a traditional Chinese medicine, Bu-zhong-yi-qi-tang on the protection
against an oral infection with Listeria monocytogenes.
AB - The protective effect against an oral infection with Listeria monocytogenes was
observed in BALB/c mice who were orally administered a traditional Chinese
medicine, Bu-zhong-yi-qi-tang (Japanese name: Hochu-ekki-to, HOT) daily for 7
days. Bacterial numbers in the Peyer's patch (PP) at 18 h, in the mesenteric
lymph nodes (MLN) at 18 h, 1 day and 3 days and in the liver at 3 days after
infection were significantly suppressed in HOT-treated mice, although there was
no difference in the bacterial number in the small intestinal contents. The
enhanced bactericidal activities of PP and liver macrophages by pretreatments of
HOT were observed. The protective effect of HOT was not observed in athymic nu/nu
and IFN-gamma deficient mice. The administration of HOT increased IFN-gamma
producing cells in the intestinal intraepithelial lymphocytes (IEL) but did not
in the PP, MLN and liver. HOT exerts effects mainly on CD8alphabeta+ IEL which
are thymus-dependent, and induced IFN-gamma production from their cells. These
results suggest that HOT acts on the gut-associated lymphoid tissues and induces
IFN-gamma from CD8alphabeta+ IEL, which activates PP and liver macrophages and
consequently the resistance to L. monocytogenes is augmented in the mice.
PMID- 9754908
TI - Modulation of serum histamine releasing activity in chronic idiopathic urticaria.
AB - BACKGROUND: Sera of about 30% of patients with chronic idiopathic urticaria (CIU)
have increased histamine releasing activity (HRA+) on normal basophils. It is not
known whether other CIU sera would be HRA+ if a more sensitive histamine release
assay was used. Although most HRA+ CIU sera appear to have anti Fc(epsilon)R1
activity, it is not known whether post-binding basophil intracellular events are
similar to those after anti-IgE stimulation. RESULTS: In the presence of D2O, the
HR stimulated by 28 previously documented HRA- sera increased from 4+/-0.4 to
21+/-4% with 13 of the 28 sera now considered HRA+. No previous HRA sera was HRA+
with IL-3 treated cells. Histamine release induced by both HRA+ sera and anti-IgE
were inhibited by genistein, and Ca2+/Mg2+ depletion but not by
bisindoylmaleimide. HRA+ sera induced prominent HR from normal basophils with
little surface IgE, but induced no increased HR from basophils unresponsive to
anti-IgE. CONCLUSIONS: Up to 61% of CIU sera will induce increased HR from normal
basophils in a sufficiently sensitive assay system. HR induced by most HRA+ sera
is more prominent in basophils with very little surface IgE. However, there may
be similar post-binding intracellular activation pathways following stimulation
by HRA+ sera and anti-IgE.
PMID- 9754909
TI - Different bronchial responsiveness to Ach between normal and OA-sensitized guinea
pigs after acoustic stress: a role for adenosine.
AB - Noise-exposure makes non-sensitized guinea pigs hyporesponsive to Acetylcholine
(Ach), while in Ovalbumin (OA)-sensitized guinea pigs the responsiveness to the
cholinergic mediator is not modified by acoustic stress (Nieri et al., 1996). The
occurrence of bronchial hyporesponsiveness after acoustic stress in non
sensitized guinea pigs was verified also with histamine, obtaining a result
similar to that observed with Ach. Moreover, the role of adenosine as modulator
of the bronchial responsiveness to Ach after noise-exposure was assessed both in
normal and in sensitized guinea pigs. In non-sensitized noise-exposed guinea
pigs, the hyporesponsiveness to Ach was abolished by pretreatment of the animals
with the peripheral A1/A2 antagonist 8-p-(sulfophenyl)theophylline (8-pSPT, 3
mg/kg i.v.) or with the A2-selective blocker 3,7-dimethyl-1-propargylxanthine
(DMPX, 80 microg/kg i.v.) but not with the A1-selective antagonist Xanthine Amine
Congener (XAC, 0.1 mg/kg i.v.). In sensitized guinea pigs, pretreatment with
theophylline (25 mg/kg i.v.) makes noise-exposed animals again hyporesponsive to
Ach, while no effect was obtained with the selective A1 and A2 antagonists
employed. Also enprofylline (10 mg/kg i.v.), a phosphodiesterase inhibitor more
potent than theophylline, does not modify the responsiveness to Ach in sensitized
noise-exposed guinea pigs. The overall data presented suggest the involvement of
the peripheral purinergic system in the regulation of airway reactivity after the
stressful condition and indicate an altered functionality of this system as a
consequence of sensitization. Furthermore, noise-exposure makes it possible to
reveal in guinea pigs an opposite influence by theophylline on airway
responsiveness to Ach, in sensitized, with respect to normal, animals.
PMID- 9754910
TI - Induction of human B2 bradykinin receptor mRNA and membrane receptors by
IFNgamma.
AB - A potential mechanism for the increased sensitivity of inflamed tissues to
bradykinin is the upregulation of bradykinin receptor expression. We report that
recombinant human IFNgamma stimulated a concentration-dependent increase in cell
surface bradykinin receptor expression in intact T24 human epithelial-like cells,
determined by radioligand binding analysis. Analysis of specific [3H]-bradykinin
binding revealed that IFNgamma-treated cells had a two- to threefold increase in
bradykinin receptor number compared to the controls with no effect on receptor
affinity. The ability of IFNgamma to stimulate increased bradykinin receptor
expression was abrogated by treatment with either the transcription inhibitor
actinomycin D or the protein synthesis inhibitor cycloheximide. IFNgamma enhanced
steady-state human B2 bradykinin receptor mRNA expression in the T24 cells in a
dose-dependent manner. B2 bradykinin receptor mRNA expression was increased as
early as 1 h following IFNgamma stimulation, and continued to accumulate for 24
h. Bradykinin-stimulated intracellular calcium mobilization was also increased in
IFNgamma-treated T24 cells compared to controls. The ability of IFNgamma to
upregulate B2 bradykinin receptors in primary epithelial cells was demonstrated
using cultured human airway epithelial cells. These observations suggest that
increasing IFNgamma levels during inflammation may upregulate the expression of
B2 bradykinin receptors, leading to increased sensitivity to bradykinin.
PMID- 9754911
TI - Vascular leak syndrome: a troublesome side effect of immunotherapy,
Immunopharmacology, 39/3 (1998) 255.
PMID- 9754912
TI - Anxiolytic-like action of neurokinin substance P administered systemically or
into the nucleus basalis magnocellularis region.
AB - There is evidence that the neurokinin substance P plays a role in neural
mechanisms governing learning and reinforcement. Reinforcing and memory-promoting
effects of substance P were found after it was injected into several parts of the
brain and intraperitoneally. With regard to the close link between anxiety and
memory processes for negative reinforcement learning, the aim of the present
study was to gauge the effect of substance P on anxiety-related behaviors in the
rat elevated plus-maze and social interaction test. Substance P was tested at
injection sites where the neurokinin has been shown to promote learning and to
serve as a reinforcer, namely in the periphery (after i.p. administration) and
after injection into the nucleus basalis magnocellularis region. When
administered i.p., substance P had a biphasic dose-response effect on behavior in
the plus-maze with an anxiolytic-like action at 50 microg/kg and an anxiogenic
like one at 500 microg/kg. After unilateral microinjection into the nucleus
basalis magnocellularis region, substance P (1 ng) was found to exert anxiolytic
like effects, because substance P-treated rats spent more time on the open arms
of the plus-maze and showed an increase in time spent in social interaction.
Furthermore, the anxiolytic effects of intrabasalis substance P were sequence
specific since injection of a compound with the inverse amino acid sequence of
substance P (0.1 to 100 ng) did not influence anxiety parameters. These results
show that substance P has anxiolytic-like properties in addition to its known
promnestic and reinforcing effects, supporting the hypothesis of a close
relationship between anxiety, memory and reinforcement processes.
PMID- 9754913
TI - Ethanol-reinforced behaviour in the rat: effects of uncompetitive NMDA receptor
antagonist, memantine.
AB - Ethanol has been reported to alter NMDA receptor-mediated biochemical and
electrophysiological responses in vitro. The aim of the present study was to
evaluate the effects of an uncompetitive NMDA receptor antagonist memantine, in
animal models of alcoholism. Male Wistar rats were trained to drink 8% ethanol in
a free-choice, limited access procedure. A separate group of animals was trained
to lever press for 8% ethanol in an operant procedure where ethanol was
introduced in the presence of sucrose. The selectivity of memantine's actions was
assessed by studying its effects on food or water consumption in separate control
experiments. Memantine (4.5-24 mg/kg) significantly, but not dose dependently,
affected ethanol drinking in the limited access procedure. However, only 6 mg/kg
memantine selectively decreased ethanol drinking. Memantine did not alter ethanol
intake in rats trained to lever press for ethanol in the operant procedure. Only
9 mg/kg memantine reduced operant responding in the extinction procedure in the
rats trained to lever press for ethanol. The same dose of memantine significantly
reduced the operant behaviour of rats trained to respond for water. These results
indicate that: (i) single doses of memantine only moderately and not dose
dependently reduce alcohol drinking in the limited access procedure; (ii)
memantine produces non-selective effects on operant behaviour in rats trained to
lever press for ethanol in an oral self-administration procedure.
PMID- 9754914
TI - Autoradiographic study of [3H]flunitrazepam binding sites in the subnuclei of the
thalamus of rats rendered tolerant to and dependent on pentobarbital.
AB - We examined changes in benzodiazepine binding sites labeled by [3H]flunitrazepam
in five nuclei of the thalamus, the central medial, central lateral,
intermediodorsal, ventroposterior, and laterodorsal nuclei, in rats made tolerant
to and dependent on pentobarbital. Animals were made tolerant by
intracerebroventricular infusion with pentobarbital (300 microg (10 microl)(-1)
h(-1) for six days) through pre-implanted cannulae. Pentobarbital dependence was
assessed 24 h after abrupt withdrawal from pentobarbital. Pentobarbital-tolerant
rats showed no significant change in [3H]flunitrazepam binding sites (Bmax and
Kd) in any nucleus examined in the thalamus. In the rats made dependent on
pentobarbital, significant increases in the Bmax of [3H]flunitrazepam binding
without changes in Kd were noted in central medial and central lateral nuclei.
GABAergic (gamma-aminobutyric acid) neurons in the ventrobasal nucleus and in
nuclei in the midline group are important in seizure regulation and arousal.
These findings suggest that alterations of benzodiazepine receptors in certain
nuclei of thalami are involved in the physiological changes induced by
pentobarbital dependence. There were no changes in the binding parameters for
[3H]flunitrazepam in pentobarbital-tolerant rats.
PMID- 9754915
TI - Alterations in [3H]L-N(G)-nitroarginine binding in brain after transient global
or transient focal ischemia in gerbils and rats.
AB - We investigated the post-ischemic change in [3H]L-N(G)-nitroarginine binding as a
marker of nitric oxide (NO) synthase in the animal brain after transient global
ischemia or transient focal ischemia. Transient global ischemia in gerbils was
induced for 10 min followed by 1 h to 7 days of recirculation. Transient focal
ischemia in rats was induced for 45 min followed by 3 days of recirculation.
Following transient global ischemia, [3H]L-N(G)-nitroarginine binding showed a
significant increase in the striatum (17-18%) and hippocampal CA1 sector (24%) at
48 and 24 h after recirculation, respectively. The hippocampal CA3 sector also
showed a significant elevation (32-40%) in [3H]L-N(G)-nitroarginine binding at 24
and 48 h after global ischemia. Furthermore, the dentate gyrus showed a
significant increase (30-32%) in [3H]L-N(G)-nitroarginine binding at 5, 24 and 48
h after global ischemia. Thereafter, a significant reduction in [3H]L-N(G)
nitroarginine binding was observed only in the dentate gyrus 7 days after
recirculation. In contrast, [3H]L-N(G)-nitroarginine binding was unchanged in the
thalamus throughout the recirculation periods. Histological analysis revealed
that transient global ischemia caused severe damage or cellular damage in the
striatum and the hippocampal CA1 sector. The hippocampal CA3 sector and thalamus
were mildly damaged, whereas the dentate gyrus was morphologically intact.
Following transient focal ischemia, a marked elevation (50-52%) in [3H]L-N(G)
nitroarginine binding was found in the regions of the ipsilateral striatum in
which severe infarction occurred. Our findings suggest that [3H]L-N(G)
nitroarginine binding increases in the striatum and hippocampus after transient
global ischemia or transient focal ischemia. This increase in [3H]L-N(G)
nitroarginine binding may play a pivotal role not only in the pathogenesis of
ischemic brain damage, but also in the restoration of injury areas after cerebral
ischemia.
PMID- 9754916
TI - Protective effect of N-(3-(aminomethyl)benzyl) acetamidine, an inducible nitric
oxide synthase inhibitor, in brain slices exposed to oxygen-glucose deprivation.
AB - It has been suggested that large amounts of nitric oxide (NO) produced by
inducible NO synthase are involved in the mechanisms of neurotoxicity after
cerebral ischaemia. We have recently demonstrated that inducible NO synthase was
expressed within hours after rat forebrain slices were exposed to oxygen-glucose
deprivation. Therefore, we sought to determine whether NO produced by inducible
NO synthase contributes to tissue damage in this model, by using a new, highly
selective, inhibitor of inducible NO synthase, N-(3
(aminomethyl)benzyl)acetamidine (1400W). We found that incubation with 1400W from
the start of the oxygen-glucose deprivation period until the end of the
experiment decreases tissue damage determined as lactate dehydrogenase (LDH)
efflux 4 h after the oxygen-glucose deprivation period, the time at which
inducible NO synthase expression is maximal in this model. This effect may be a
result of direct inhibition of inducible NO synthase activity, raising the
possibility of a clinical use of selective inhibitors of this NO synthase isoform
in the management of cerebral ischaemia.
PMID- 9754917
TI - Biochemical, cellular and pharmacological activities of a human neuropeptide FF
related peptide.
AB - We report on the biochemical, cellular and pharmacological activities of SQA
neuropeptide FF (Ser-Gln-Ala-Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2), a peptide
sequence contained in the human neuropeptide FF (neuropeptide FF, Phe-Leu-Phe-Gln
Pro-Gln-Arg-Phe-NH2) precursor. Quantitative autoradiography revealed that, in
the superficial layers of the rat spinal cord, SQA-neuropeptide FF displayed the
same high affinity for [125I]1DMe ([125I]D-Tyr-Leu-(NMe)Phe-Gln-Pro-Gln-Arg-Phe
NH2) binding sites (Ki = 0.33 nM) as did neuropeptide FF (Ki = 0.38 nM). In
acutely dissociated mouse dorsal root ganglion neurones, SQA-neuropeptide FF
reduced by 40% the depolarisation-induced rise in intracellular Ca2+ as measured
with the Ca2+ indicator, Fluo-3. In mice, 1DMe and SQA-neuropeptide FF dose
dependently inhibited the antinociceptive effect of intracerebroventricular
(i.c.v.) injections of morphine, but SQA-neuropeptide FF was less potent than
1DMe. Furthermore, SQA-neuropeptide FF, as well as 1DMe, produced marked
hypothermia following third ventricle injections in mice. These data demonstrate
that the human peptide, SQA-neuropeptide FF, exhibits biochemical and
pharmacological properties similar to those of neuropeptide FF or neuropeptide FF
analogues, and belongs to the neuropeptide FF family.
PMID- 9754918
TI - Interspecies differences in thromboxane A2 receptors are distinguished by
glibenclamide.
AB - The ability of the thromboxane A2 receptor antagonist, GR32191 ([1R
[1alpha(Z),2beta3beta,5alpha]]-7-[5-[[(1,1'-biphe nyl)-4-yl]methoxy]-3-hydroxy-2
(1-piperidinyl)cyclopentyl]-4-heptenoic acid), and the sulphonylurea,
glibenclamide, to antagonise contractions to the thromboxane A2 mimetic, U46619
((15S)-hydroxy-11alpha,9alpha(epoxymethano)prosta-5Z, 13E-dienoic acid), were
assessed in rat and guinea-pig isolated large (aorta) and small (mesentery and
coronary) arteries. U46619 concentration-response curves were constructed in the
absence and presence of GR32191 and glibenclamide and pKB values calculated.
GR32191 caused significant rightward shifts in U46619 concentration-response
curves and was a more potent antagonist in guinea-pig vessels (pKB approximately
9.4) than rat arteries (pKB approximately 7.9). Conversely, glibenclamide failed
to inhibit contractions to U46619 in guinea-pig vessels but antagonised responses
to U46619 in rat aorta (pKB = 6.1) and mesenteric artery (pKB = 6.3). In
combination, GR32191 and glibenclamide caused a shift in the concentration-effect
curve to U46619 in rat aorta that was additive. These results suggest that
glibenclamide can discriminate between species differences in thromboxane A2
receptors and may exert its inhibitory effect upon U46619-mediated contractions
at the level of the thromboxane A2 receptor.
PMID- 9754919
TI - Possible mechanism for the anemia induced by candesartan cilexetil (TCV-116), an
angiotensin II receptor antagonist, in rats.
AB - Candesartan cilexetil (TCV-116), an angiotensin II receptor antagonist, was
administered orally to male F344/Jcl and Crj:CD (SD) rats at 1000 mg kg(-1) day(
1) for 1-28 days, and the possible mechanism for the anemia induced by TCV-116
was investigated. In the TCV-116 group, the erythrocyte count, hematocrit value
and hemoglobin concentration were decreased by 7-8% as compared with the values
in the control group after dosing for 28 days. The plasma and renal
erythropoietin levels, the reticulocyte count in the peripheral blood and the
erythroid cell count upon bone marrow examination were decreased on day 7, but
there were no accompanying histopathological renal lesions. Renal blood flow was
increased, and mean blood pressure was decreased after TCV-116. These results
suggest that the primary cause of the anemia induced by TCV-116 treatment is the
increase in renal blood flow followed by a decrease in erythropoietin production.
PMID- 9754920
TI - Anti-ulcer effects of antioxidants: effect of probucol.
AB - We investigated the effect of probucol, a lipid-lowering agent with antioxidant
properties, on HCl plus ethanol-induced gastric mucosal injury and on the healing
of acetic acid-induced gastric ulcers in rats. When the free radical-scavenging
activity of probucol was measured by an electron spin resonance technique, the
agent (10(-5)-10(-3) M) scavenged both superoxide anions and hydroxyl radicals.
Oral administration of probucol (250-1000 mg/kg) dose dependently prevented the
HCl plus ethanol-induced gastric mucosal injury and the increase in
thiobarbituric acid-reactive substances, an index of lipid peroxidation, in the
injured mucosa. Repeated oral administration of probucol (250-1000 mg/kg twice
daily) dose dependently accelerated the healing of acetic acid-induced gastric
ulcers. In addition, probucol already inhibited the increase in the content of
thiobarbituric acid-reactive substances in the ulcerated region before the ulcer
healing effect of this agent was recognized. These results suggest that probucol
may partly protect gastric mucosa from acute gastric mucosal injury and promote
the healing of chronic gastric ulcers by its antioxidant activity.
PMID- 9754921
TI - Glucocorticosteroids and in vitro effects on chemiluminescence of isolated bovine
blood granulocytes.
AB - The effects of glucocorticosteroids on respiratory burst of bovine granulocytes
were studied in vitro by means of (1) chemiluminescence (luminol-dependent,
phorbol 12-myristate 13-acetate (PMA)-stimulated), (2) a cell-free
chemiluminescence assay, and (3) a myeloperoxidase assay. Significant effects on
cellular chemiluminescence were only observed at the highest, not obtainable in
vivo, concentration for all drugs except betamethasone. Prednisolone induced
inhibition at therapeutic doses. Also, flumethasone and dexamethasone induced
significant inhibition at lower concentrations. In the cell-free assay, all
glucocorticosteroids, except betamethasone, inhibited chemiluminescence at high
concentrations. None of the glucocorticosteroids tested affected myeloperoxidase
activity. The results indicated that the drugs do not affect NADPH-oxidase
activity. The adverse effects may be due to scavenging of free oxygen radicals,
or to interference with the interaction between luminol and the myeloperoxidase
H2O2-halide system. It can be concluded that most glucocorticosteroids show no
adverse effects on the respiratory burst of bovine granulocytes in vitro at
therapeutical concentrations.
PMID- 9754922
TI - 2-Phenyl-4-quinolone prevents serotonin-induced increases in endothelial
permeability to albumin.
AB - To investigate the role of 2-phenyl-4-quinolone in enhancing endothelial
monolayer paracellular barrier function and preventing the disturbance of
paracellular barrier function by vasoactive agents, the study examined the effect
of 2-phenyl-4-quinolone on serotonin-mediated macromolecule transfer and
microfilament changes in cultured rat heart endothelial cells. Serotonin-treated
endothelial cells induced concentration-dependent increases in the passage of
Evans blue dye-bound bovine serum albumin. Incubation of the endothelial
monolayers with 2-phenyl-4-quinolone antagonized serotonin- and cytochalasin B
induced macromolecular permeability. 2-Phenyl-4-quinolone also opposed the effect
of serotonin or cytochalasin B on the distribution and quantity of actin
filaments in the endothelial cytoskeleton. Furthermore, 2-phenyl-4-quinolone
alone led to an apparent quantitative increase in F actin fluorescence in
endothelial cells. The addition of 10(-7) M 2-phenyl-4-quinolone had an effect on
serotonin-induced changes in the myosin and distribution of myosin were
comparable to that on serotonin monolayers. In conclusion, 2-phenyl-4-quinolone
attenuated the serotonin-induced permeability of rat heart endothelial cells and
this was associated with stabilization of F actin microfilaments and changes in
the myosin organization. This result suggests that influences on cytoskeletal
assembly may be involved in this process.
PMID- 9754923
TI - Modulation of the chemotactic peptide- and immunoglobulin G-triggered respiratory
burst in human neutrophils by exogenous and endogenous adenosine.
AB - The effects of exogenous and endogenous adenosine on the production of oxygen
metabolites in neutrophils triggered by the chemotactic peptide N-formyl
methionyl-leucyl-phenylalanine (fMLP) or immunoglobulin G (IgG)-opsonized yeast
particles, were investigated. By using luminol-enhanced chemiluminescence, we
found that adenosine A1 receptor activation did not affect, whereas adenosine A
receptor activation, through a mechanism involving the cyclic AMP (cAMP)-protein
kinase A signalling pathway, both inhibited the fMLP- and IgG-triggered
respiratory burst. The adenosine-induced inhibition was however more pronounced
after exposure to fMLP than to IgG-yeast. Stimulation with fMLP caused an
extracellular accumulation of endogenous adenosine, which indicates that this
event is a negative-feedback mechanism preventing an uncontrolled activation of
chemoattractant-stimulated neutrophils. On the contrary, exposure of neutrophils
to IgG-yeast did not appear to accumulate extracellular adenosine, probably due
to increased adenosine deaminase activity during phagocytosis. In conclusion,
this work accentuates the importance of adenosine, both exogenously applied and
endogenously formed, as an inflammatory agent modulating the respiratory burst
during the different phases in neutrophil activation.
PMID- 9754924
TI - Apparent thermodynamic parameters of ligand binding to the cloned rat mu-opioid
receptor.
AB - The apparent thermodynamic parameters of binding of ten ligands to the cloned rat
mu-opioid receptor stably expressed in Chinese hamster ovary (CHO) cells were
investigated. For every ligand, the Kd or Ki values at 0 degrees C, 12 degrees C,
25 degrees C and 37 degrees C were determined, a van't Hoff plot was generated
and deltaH degrees' , deltaS degrees' and -TdeltaS degrees' and deltaG degrees'
were calculated. Changes in free energy (deltaG degrees') ranged from -10.35 to
15.65 kcal/mol. The binding of sufentanil, ohmefentanyl, diprenorphine and D-Phe
Cys-Tyr-D-Trp-Arg-Thr-penicillamineThr-NH2 (CTAP) was endothermic (deltaH
degrees' > 0) and driven by an increase in entropy (-TdeltaS degrees' = -13.08 to
-18.57 kcal/mol). The binding of naltrexone was exothermic (deltaH degrees' =
12.56 kcal/mol) and essentially enthalpy-driven. The binding of morphine,
methadone, pentazocine, [D-Ala2, NMePhe4, Gly-ol]enkephalin (DAMGO) and Tyr-Pro
NMePhe-D-Pro-NH2 (PL017) was exothermic (deltaH degrees' = -3.53 to -9.95
kcal/mol) and occurred with an increase in entropy (-TdeltaS degrees' = -2.48 to
7.92 kcal/mol). Plots of enthalpy versus entropy and enthalpy versus free energy
were linear, although enthalpy-entropy compensation was not evident. The entropy
changes were not correlated with apparent lipophilicity of the compounds. These
results suggest that: (1) opioid ligands bind to the mu receptor by specific
mechanisms, unrelated to lipid solubility; (2) the mechanism of binding is not
universally different for peptide and non-peptide ligands; (3) the nature of
binding does not a priori determine intrinsic activity. The results reveal a
novel differentiation of opioid ligands into two groups (group 1: ohmefentanyl,
sufentanil, diprenorphine, CTAP and PL017; group 2: naltrexone, morphine,
methadone, DAMGO, pentazocine), based on two distinct relationships between
enthalpy versus free energy of binding, the details of which are yet to be
elucidated.
PMID- 9754925
TI - Ethanol affects the function of a neurotransmitter receptor protein without
altering the membrane lipid phase.
AB - Using patch-clamp and fluorescence techniques we found that ethanol (10-200 mM)
potentiated strychnine-sensitive glycine receptors without having detectable
effects on lipid order parameters in mouse spinal cord neurons. Hepthanol (0.01-1
mM), in contrast, did not affect the glycine current, but it altered the core and
surface of spinal neuron membranes as detected by changes in 1,6-diphenyl-1,3,5
hexatriene (DPH) and Laurdan fluorescence parameters. These findings support the
idea that ethanol affects these membrane proteins without changing lipid
fluidity.
PMID- 9754926
TI - 2-Hydroxycarbazole induces Ca2+ release from sarcoplasmic reticulum by activating
the ryanodine receptor.
AB - 2-Hydroxycarbazole was shown to induce Ca2+ release from skeletal muscle and
cardiac muscle sarcoplasmic reticulum at concentrations between 100-500 microM.
This release was blocked by both 1 mM tetracaine and 30 microM ruthenium red
which inhibit the ryanodine receptor or by pre-treatment with 10 mM caffeine
which depletes the ryanodine receptor-containing Ca2+ stores. This, in addition
to the fact that 2-hydroxycarbazole has little effect on Ca2+ ATPase activity,
indicates that it activates Ca2+ release through the ryanodine receptor. The
apparent EC50 value for release from both skeletal muscle and cardiac muscle
sarcoplasmic reticulum was approximately 200 microM and maximal release occurred
at 400-500 microM, making it approximately 20 times more potent than caffeine.
The dose-dependency in the extent of Ca2+ release induced by 2-hydroxycarbazole
was also apparently highly cooperative for both preparations. That 2
hydroxycarbazole was able to mobilize Ca2+ from non-muscle cell microsomes and in
intact TM4 cells (which contain ryanodine receptors), makes this compound a more
potent and commercially available alternative to caffeine in studying the role of
this intracellular Ca2+ channel in a variety of systems.
PMID- 9754927
TI - Chicken GABA(A) receptor beta4 subunits form robust homomeric GABA-gated channels
in Xenopus oocytes.
AB - Chicken GABA(A) receptor beta4L and beta4S subunits were expressed in Xenopus
oocytes by cRNA injection. Oocytes expressing either beta4 subunit alone or in
combination with the chicken alpha1 subunit were studied using the two-electrode
voltage-clamp technique. Both the beta4L and beta4S subunits form homomeric GABA
gated Cl- channels with similar efficiencies. In comparison, oocytes expressing
either the chicken alpha1 or beta2S polypeptide show no or barely detectable GABA
responses, as reported by others for most single-subunit vertebrate GABA(A)
receptors. The GABA-gated currents due to the beta4L-subunit homomer were not
affected by the presence of actinomycin D during cRNA expression, indicating that
nascent oocyte polypeptides are not required for channel formation. The homomeric
beta4L-subunit receptors show high affinity for GABA with an EC50 value of 4.3 +/
0.4 microM and a Hill coefficient of 1.1 +/- 0.1 (n = 6). In response to GABA
application at the EC25 value, currents elicited from the beta4L-subunit receptor
are enhanced by 50 microM pentobarbital (110 +/- 10%, n = 3) and 10 microM
loreclezole (60 +/- 3%, n = 3), inhibited by 10 microM picrotoxinin (93 +/- 3%, n
= 3), but not affected by 1 microM diazepam. These properties are similar to
those found for oocytes expressing heteromeric chicken alpha1beta4L and
alpha1beta2S receptors. Since the beta subunits of GABA(A) receptors provide
essential determinants for receptor assembly and subcellular localization,
homomeric beta4-subunit receptors are a useful model system for further study of
the structure and function of GABA(A) receptors.
PMID- 9754928
TI - Inhibition of ligand-gated cation-selective channels by tamoxifen.
AB - The nonsteroidal antioestrogen tamoxifen has been shown to block a number of
voltage-gated cation-selective channels but its effect on ligand-gated cation
selective channels has not been studied. We have investigated the action of
tamoxifen and the related derivative toremifene on ligand-gated cationic
nicotinic acetylcholine and 5-HT3 receptor channels. Tamoxifen and toremifene
both inhibited cationic currents of adult-type human muscle nicotinic
acetylcholine receptors expressed in Xenopus oocytes with similar IC50 values of
1.2 +/- 0.03 microM (nH = 0.84 +/- 0.02) and 1.2 +/- 0.1 microM (nH = 1.1 +/-
0.1), respectively. Tamoxifen could also block native 5-HT3 receptors in NG108-15
neuroblastoma/glioma hybrid cells with IC50 = 0.81 +/- 0.15 microM and nH of 1.3
+/- 0.3. The characteristics of block by tamoxifen at the 5-HT3 receptor were
voltage- and use-independent. The inhibition of the 5-HT-evoked currents were not
overcome by increasing concentrations of 5-HT consistent with a noncompetitive
mechanism of block.
PMID- 9754929
TI - Effects of insulin-like growth factor I and II on DNA synthesis and proliferation
in primary cultures of adult rat hepatocytes.
AB - We compared the effects of insulin-like growth factor I (IGF-I) and II (IGF-II)
on DNA synthesis and proliferation and investigated various signal transduction
mechanisms involved in insulin-like growth factor-induced mitogenesis in primary
cultures of adult rat hepatocytes. IGF-I stimulated hepatocyte DNA synthesis and
proliferation with an EC50 of 75 ng/ml within 4 h of culture. These effects were
sensitive to the IGF-I concentration and cell density. Hepatocyte proliferation
induced by IGF-I was potentiated by metaproterenol (10(-6) M) as well as by 8
bromo-cAMP, phorbol 12-myristate 13-acetate (PMA; 10(-8) M) and was inhibited by
U-73122 (1-(-[[17beta-3-methoxyestra-1,3,5(10)-triene-17-yl]amino]hexyl]-+
++1Hpyrrol-2,5-dione)), genistein, wortmannin, PD98059 (2'-amino-3'
methoxyflavone) and rapamycin. The IGF-I effect was independent of pertussis
toxin (100 ng/ml). IGF-II also dose dependently stimulated hepatocyte DNA
synthesis and proliferation with an EC50 of 0.75 ng/ml within 4 h of culture.
However, these effects were not dependent on the initial plating density. The
stimulatory effects of IGF-II were potentiated by UK-14304 (5-bromo-6-[2
imidazolin-2-ylamino]-quinoxaline) (10(-5) M) and inhibited by phenylephrine,
PMA, metaproterenol, 8-bromo-cAMP, PD98059, rapamycin, and pertussis toxin. The
IGF-II effects were not affected by genistein, U-73122, and wortmannin. These
results suggest that IGF-I and IGF-II rapidly stimulate the DNA synthesis and
proliferation of adult rat hepatocytes by separate mechanisms.
PMID- 9754930
TI - Amino acid residue 200 on the alpha1 subunit of GABA(A) receptors affects the
interaction with selected benzodiazepine binding site ligands.
AB - Mutant alph1 subunits of the GABA(A) receptor were coexpressed in combination
with the wild-type beta2 and gamma2 subunits in human embryonic kidney (HEK) 293
cells. The binding properties of various benzodiazepine site ligands were
determined by displacement of ethyl-8-fluoro-5,6-dihydro-5-methyl-6-oxo-4H
imidazo[1,5a]-[1,4]benzodia zepine-3-carboxylate ([3H]Ro 15-1788). The mutation
G200E led to a decrease in zolpidem and 3-methyl-6-[3-(trifluoromethyl)phenyl]
1,2,4-triazolo[4,3-b]pyridazine (CL 218872) affinity amounting to 16- and 8-fold.
Receptors containing a conservative T206V substitution showed a 41- and 38-fold
increase in methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) and
CL 218872 affinity combined with a decrease in diazepam and zolpidem affinity,
amounting to 7- and 10-fold. Two mutations, Q203A and Q203S showed almost no
effects on the binding of benzodiazepine site ligands, indicating that this
residue is not involved in the binding of benzodiazepines and related compounds.
PMID- 9754931
TI - Studies on the teratogen pharmacophore of valproic acid analogues: evidence of
interactions at a hydrophobic centre.
AB - Propyl-4-yn-valproic acid (2-propyl-4-pentynoic acid), an analogue of valproic
acid with a triple bond in one alkyl side chain, potently induces exencephaly in
mice. Given that propyl-4-yn-valproic acid is a branched chain carboxylic acid,
we synthesized a series of analogues with n-alkyl side chains of increasing
length and correlated their potential to induce neural tube defects and to
inhibit proliferation and induce differentiation in cells of neural origin, the
latter being crucial to the orderly structuring of the embryo. All analogues
significantly increased the incidence of neural tube defects in the embryos of
dams exposed to a single dose of 1.25 mmol/kg on day 8 of gestation. This effect
occurred in a dose-dependent manner and the rate of exencephaly increased with
the progressive increase in n-alkyl side chain length. Moreover, increasing chain
length resulted in a dose-dependent inhibition of C6 glioma proliferation rate
over a concentration range of 0-3 mM and this was independent of the cell type
employed and mode of estimating proliferative rate. The antiproliferative action
of these analogues was associated with profound shape change in neuro-2A
neuroblastoma involving extensive neuritogenesis and an associated increase in
neural cell adhesion molecule (NCAM) prevalence at points of cell-cell contact,
the latter exhibiting a dose-dependent increase when the n-alkyl chain was
extended to five carbon units. These results suggest an interaction with a
specific site in which the n-alkyl side is proposed to serve as an 'anchor'
within a hydrophobic pocket to facilitate the ionic and/or H-bonding of the
carboxylic acid and high electron density of the carbon-carbon triple bond.
PMID- 9754932
TI - Sigma receptor ligands (+)-SKF10,047 and SA4503 improve dizocilpine-induced
spatial memory deficits in rats.
AB - This study examined the effects of the sigma receptor ligands (+)-N
allylnormetazocine ((+)-SKF10,047) and 1-(3,4-dimethoxyphenethyl)-4-(3
phenylpropyl)piperazine dihydrochloride (SA4503) on dizocilpine-induced
impairment of working and reference memory in a radial arm maze task in rats.
Dizocilpine, a non-competitive NMDA receptor antagonist, significantly impaired
both reference and working memory, an effect which was accompanied by ataxia and
impairment of food intake. The dizocilpine-induced impairment of reference memory
was dose-dependently attenuated by (+)-SKF10,047 and SA4503. SA4503 also
attenuated the dizocilpine-induced working memory impairment, although (+)
SKF10,047 had no effect. Neither sigma receptor ligand affected the behavioral
symptoms such as ataxia and impairment of food intake induced by dizocilpine. The
ameliorating effects of both (+)-SKF10,047 and SA4503 on dizocilpine-induced
spatial memory impairment were completely antagonized by a sigma1 receptor
antagonist N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine-mon
ohydrochloride. These results suggest that the interaction of sigma1 receptors
with NMDA receptors modulates spatial memory in rats.
PMID- 9754933
TI - Vasopressin opposes locomotor stimulation by ethanol, cocaine and amphetamine in
mice.
AB - The effects of arginine8-vasopressin on the stimulation of locomotor activity
induced by ethanol, cocaine and amphetamine were examined in DBA/2N mice.
Locomotor activity was measured by photocell beam interruption for a period of 45
min following ethanol, cocaine or amphetamine administration. Pretreatment with
vasopressin alone in a dose of 2 (but not 1) microg/mouse s.c. reduced locomotor
activity. The low dose of vasopressin did not modify the stimulation of locomotor
activity induced by i.p. administration of ethanol in doses of either 1.5 or 2
g/kg. The high dose of vasopressin reduced locomotor activity induced by both
doses of ethanol, in an apparently additive manner. Cocaine in doses of 15 and 20
mg/kg strongly stimulated locomotor activity, but this stimulation was completely
antagonized by pretreatment with 1 microg of vasopressin. Similarly, the
stimulation of locomotor activity induced by amphetamine (5 mg/kg) was also
blocked by pretreatment with vasopressin. These findings raise the possibility
that the effect of vasopressin varies with the extent and nature of dopaminergic
involvement in the drug-induced stimulation of activity. For drugs like cocaine
or amphetamine which stimulate locomotor activity primarily through the
mesolimbic dopaminergic system, vasopressin can completely antagonize the
stimulation. For ethanol, which stimulates locomotor activity through action on a
number of other neurotransmitters as well as dopamine, vasopressin treatment only
reduces its stimulation of locomotor activity in an additive manner. These
results suggest a close interaction between vasopressin and dopamine action.
PMID- 9754934
TI - Cocaine sensitization prevents the hypolocomotor effects of high but not low
doses of PD 128,907.
AB - In this study we examined the effects of the preferential dopamine D3 receptor
agonist S(+)-(4aR,10bR)-3,4,4a,10b-tetrahydro-4-propyl-2H,5H-[1]b enzopyrano-[4,3
b]-1,4-oxazin-9-ol (PD 128,907) on locomotion in mice sensitized to cocaine. In
mice repeatedly treated with saline, PD 128,907 induced hypoactivity over a wide
dose range (0.01-40 mg/kg); however, after repeated treatment with 40 mg/kg
cocaine, higher doses of PD 128,907 (2.5-40 mg/kg) no longer induced hypoactivity
whereas the effects of lower doses (0.01-0.16 mg/kg) were not altered. Because
lower doses of PD 128,907 are thought to induce hypoactivity via activation of
dopamine D3 receptors, the present data suggest that, under conditions where
cocaine induces marked sensitization to its locomotor effects, the sensitivity of
these receptors is not altered. In contrast, because higher doses of PD 128,907
can activate dopamine D2 receptors, it is conceivable that apparent cross
sensitization to its dopamine D2 receptor agonist properties is responsible for
the lack of hypolocomotor effects at high doses. Overall, the results indicate
that altered dopamine D3 receptor sensitivity does not play an important role in
the expression of cocaine-induced sensitization.
PMID- 9754935
TI - Effects of nonintermittent treatment of rabbits with pentaerythritol tetranitrate
on vascular reactivity and superoxide production.
AB - Pentaerythritol tetranitrate is an organic nitrate ester that undergoes
metabolization to pentaerythritol, pentaerythritol trinitrate, pentaerythritol
dinitrate and pentaerythritol mononitrate. Recent data suggested that
pentaerythritol tetranitrate is endowed with vasoprotective activities in
experimental atherosclerosis. This study was undertaken to gain insight into the
underlying mechanism. The basic mechanism of action of all pentaerythritol
nitrates was evaluated by measuring liberation of nitric oxide (NO), stimulation
of human soluble guanylate cyclase and vasorelaxation in rabbit aorta. A
subsequent in vivo study in New Zealand White rabbits was performed to
investigate the effects of a 4 months lasting nonintermittent oral treatment with
6 mg pentaerythritol tetranitrate kg(-1) day(-1) on vascular superoxide
production, endothelium dependent vasorelaxation and vasorelaxation to
pentaerythritol tetranitrate itself. The formation rates of NO from the
pentaerythritol nitrates (100 microM, n = 5) in presence of 5 mM cystein were (in
nM min(-1)): 62.1 +/- 3.2 (pentaerythritol tetranitrate), 21.3 +/- 0.9
(pentaerythritol trinitrate), 6.4 +/- 0.6 (pentaerythritol dinitrate) and 3.2 +/-
0.4 (pentaerythritol mononitrate). Similarly, the pD2 values (-log M) for half
maximal activation of soluble guanylate cyclase decreased from pentaerythritol
tetranitrate (3.391 +/- 0.09, n = 4) to pentaerythritol mononitrate (2.655 +/-
0.04, n = 3) as did the pD2 values (in -log M) for half-maximal relaxation of
rabbit aortic rings (n = 7) from pentaerythritol tetranitrate (8.3 +/- 0.17) to
pentaerythritol mononitrate (5.0 +/- 0.11). Significant correlations were found
between the NO formation rates and the pD2 values for enzyme stimulation (r =
0.98, P = 0.002) and vasorelaxation (r = 0.90, P = 0.049) suggesting that these
effects of the pentaerythritol nitrates were mediated by NO. The results of the
in vivo study showed that aging induces a significant increase of aortic
superoxide production (median values, n = 10) from 2.45 nM mg(-1) min(-1) (age 7
months) to 3.39 nM mg(-1) min(-1) (age 11 months, P < 0.01) that was prevented by
concurrent treatment with pentaerythritol tetranitrate (2.76 nM mg(-1) min(-1)).
In vitro vasorelaxation to pentaerythritol tetranitrate was identical in all
groups indicating absence of nitrate tolerance. Endothelium-dependent
vasorelaxation was also identical in all groups. These data suggest that oral
treatment with pentaerythritol tetranitrate reduces vascular oxidant stress by an
NO-dependent pathway, which may contribute to the vasoprotective activity of
pentaerythritol tetranitrate in experimental atherosclerosis.
PMID- 9754936
TI - Chronic infusion of adrenomedullin reduces pulmonary hypertension and lessens
right ventricular hypertrophy in rats administered monocrotaline.
AB - A novel vasorelaxant peptide, adrenomedullin, its messenger ribonucleic acid
(mRNA), and the mRNA for its receptor are highly expressed in the lung,
suggesting that adrenomedullin may play a role in the regulation of the pulmonary
circulation. We investigated whether the chronic infusion of rat adrenomedullin
would affect pulmonary hypertension and right ventricular hypertrophy produced by
the administration of monocrotaline. Four-week-old male Wistar rats received a
single subcutaneous injection of 60 mg/kg monocrotaline and were then chronically
and subcutaneously infused with rat adrenomedullin (PH + AM group, n = 8) or
saline (PH group, n = 10) by an osmotic minipump for a period of 21 days. Plasma
levels of adrenomedullin were significantly higher in the PH vs. the control
group. The chronic infusion of adrenomedullin in rats with pulmonary hypertension
increased the plasma levels of adrenomedullin to a value 94% greater than that of
the control group and 55% greater than that of the untreated PH group. Chronic
infusion of adrenomedullin significantly lessened the increase in right
ventricular systolic pressure and the ratio of right ventricular weight to body
weight seen after monocrotaline treatment. Histological examination revealed that
adrenomedullin also attenuated the medial thickening of the pulmonary artery.
These results suggest that chronic infusion of adrenomedullin attenuates the
pulmonary hypertension and right ventricular hypertrophy seen in rats treated
with monocrotaline.
PMID- 9754937
TI - Vasopressin receptors involved in adrenergic neurotransmission in the circular
muscle of the human vas deferens.
AB - We studied the effects of vasopressin on the adrenergic responses of in vitro
preparations of circular muscle from the vas deferens obtained from 28 men
undergoing elective vasectomy. Vasopressin (3 x 10(-9)-3 x 10(-8) M) enhanced the
phasic contractions elicited by electrical field stimulation and noradrenaline.
This potentiation was blocked by the vasopressin V1 receptor antagonist
d(CH2)5Tyr(Me)vasopressin (10(-6) M) but not by the vasopressin V2 receptor
antagonist [d(CH2)5, D-Ile2,Ile4,Arg8]vasopressin (10(-6) M). The Ca2+ antagonist
nifedipine (10(-6) M) did not affect the potentiation of electrical field
stimulation induced by vasopressin and noradrenaline but reduced KCl-induced
contractions and abolished the induction of phasic activity by vasopressin in the
presence of KCl. The results demonstrate that vasopressin, in addition to its
direct contractile effects, strongly potentiates contractions of human vas
deferens elicited by adrenergic stimulation. Both the direct and indirect effects
of vasopressin appear to be mediated by vasopressin V1 receptor stimulation and
are independent of Ca2+ entry through dihydropyridine Ca2+ channels.
PMID- 9754938
TI - Facilitation by endogenous acetylcholine and nitric oxide of luminal serotonin
release from the guinea-pig colon.
AB - The present study was designed to determine the influence of endogenous
acetylcholine and nitric oxide (NO) on spontaneous luminal serotonin (5
hydroxytryptamine, 5-HT) release in the luminally perfused isolated guinea-pig
proximal colon in vitro. 5-HT was determined by high-performance liquid
chromatography with electro-chemical detection. The luminal outflow of 5-HT was
significantly reduced by atropine (0.2 microM), hexamethonium (100 microM), the
NO synthase inhibitor NG-nitro-L-arginine (L-NNA, 10 microM) and the NO-trapping
agent 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy
PTIO, 30 microM). Addition of excess L-arginine (300 microM) reversed the
inhibitory effect of L-NNA on the 5-HT outflow. Physostigmine (1 microM) caused a
great increase (atropine-sensitive) in 5-HT outflow. The enhancing action of
physostigmine on 5-HT outflow was partially inhibited by L-NNA (100 microM) or
carboxy-PTIO (30 microM), but was unaffected by the muscarinic M1 receptor
antagonist pirenzepine (0.2 microM) or a muscarinic M3 receptor antagonist 4
diphenyl-acetoxy-N-methyl-piperidine methiodide (0.2 microM). These results
suggest that 5-HT release from luminally perfused proximal colon of the guinea
pig is stimulated via a NO pathway and cholinergic pathways which utilize
muscarinic synapses and nicotinic synapses. Further, an intrinsic cholinergic-NO
link appears to play a role in the stimulation of luminal 5-HT release, which may
reflect the release of 5-HT from entero-chromaffin cells.
PMID- 9754939
TI - Pulmonary actions of anandamide, an endogenous cannabinoid receptor agonist, in
guinea pigs.
AB - Anandamide (arachidonylethanolamide), 5,8,11,14-eicosatetraenamide, (N-2
hydroxyethyl), was tested for bronchodilator and anti-inflammatory activities.
Conscious guinea pigs were given cumulative i.v. doses of anandamide (1.0, 3.0,
and 10.0 mg/kg) to assess its effect on dynamic compliance (Cdyn), total
pulmonary resistance (RL), tidal volume (VT) and breathing frequency (f). Other
guinea pigs were exposed to an aerosol of A23187 (6S
[6alpha(2S*,3S*),8beta(R*),9beta,11alpha]-5- (methylamino)-2-[[3,9,11-trimethyl-8
[1-methyl-2-oxo-2-(1H-pyrrol-2-yl)e thyl]-1,7-dioxaspiro[5.5]undec-2-yl]methyl]-4
benzoxazole carboxylic acid) until Cdyn decreased by 50% (approximately 5 min)
and at 20 min, cumulative i.v. doses of anandamide (1.0, 3.0, and 10.0 mg/kg)
were administered and reversal of Cdyn examined. After the final dose of
anandamide, the animals were killed and excised lung gas volumes (ELGV), i.e.,
pulmonary gas trapping, measured. Other animals were treated i.v. with anandamide
(10.0 mg/kg), exposed to an aerosol of A23187 until labored breathing began, and
then killed 1 h later. Anandamide did not significantly affect Cdyn, RL, VT and
f. ELGV values of anandamide-treated guinea pigs were not different from those of
vehicle-treated animals. Anandamide failed to reverse A23187-induced decreases in
Cdyn and to reduce A23187-associated ELGV increases. Also, it did not prevent the
prolonged airway obstruction caused by A23187. Histological evaluation revealed
that anandamide significantly reduced A23187-related airway epithelial injury and
pulmonary leukocytosis. However, it did not prevent A23187-induced
peribronchiolar granulocytic accumulation. Our results suggest that in vivo
anandamide has minimal direct airway smooth muscle-related actions, however it
may possess modest anti-inflammatory properties.
PMID- 9754940
TI - Characterisation of new efaroxan derivatives for use in purification of
imidazoline-binding sites.
AB - The insulin secretagogue activity of certain imidazoline compounds is mediated by
a binding site associated with ATP-sensitive K+ (K(ATP)) channels in the
pancreatic beta-cell. We describe the effects of a series of structural
modifications to efaroxan on its activity at this site. Substitution of amino-,
nitro- or azide- groups onto the 5-position of the benzene ring of efaroxan did
not significantly affect the functional interaction of the ligand with the islet
imidazoline binding site. Modification of the imidazoline ring to an imidazole to
generate 2-(2-ethyl-2,3-dihydrobenzo[b]furan-2-yl)-1H-imidazole (KU14R) resulted
in loss of secretagogue activity. Indeed, this reagent appeared to act as an
imidazoline antagonist since it blocked the secretory responses to imidazoline
compounds and also inhibited the blockade of beta-cell K(ATP) channels by
efaroxan in patch clamp experiments. Application of KU14R alone resulted in a
modest reduction in K(ATP) channel opening, suggesting that it may display weak
partial agonism, at least in patch-clamp experiments.
PMID- 9754941
TI - Picotamide, an antithromboxane agent, inhibits the migration and proliferation of
arterial myocytes.
AB - Picotamide is an antiplatelet drug with a peculiar dual mechanism of action: it
inhibits thromboxane A2 synthase and antagonizes the pharmacological responses
mediated by thromboxane A2 receptor. We investigated the in vitro effect of
picotamide on smooth muscle cell migration and proliferation. Picotamide (1-500
microM) decreased human and rat smooth muscle cell proliferation, evaluated as
cell number, in a concentration-dependent and reversible manner. Picotamide
inhibited DNA synthesis induced by fetal calf serum (10%), platelet-derived
growth factor (PDGF-BB (20 ng/ml)), epidermal growth factor (EGF (1 nM)) and
(15S)-hydroxy-11,9-(epoxymethano)prosta-5Z,13E-dienoic acid (U46619 (10 microM,
thromboxane A2 receptor agonist)). Co-incubation of U46619 together with EGF or
PDGF-BB resulted in a marked amplification of [3H]thymidine incorporation that
was completely reversed by picotamide. The drug also inhibited smooth muscle cell
migration induced by fibrinogen (600 microg/ml) or PDGF-BB (20 ng/ml) in a
concentration-dependent manner. The ability of picotamide to interfere with
myocyte migration and proliferation confers, at least in vitro, a pharmacological
interest on the compound in atherogenesis.
PMID- 9754942
TI - Involvement of G-protein betagamma subunits in coupling the adenosine A1 receptor
to phospholipase C in transfected CHO cells.
AB - In transfected Chinese hamster ovary (CHO-A1) cells the human adenosine A1
receptor directly stimulates pertussis toxin-sensitive increases in inositol
phosphate production and potentiates (synergistically) the inositol phosphate
responses mediated by Gq-coupled P2Y2 purinoceptor and CCK(A) receptors. In the
present study we have investigated the role of Gbetagamma subunits in mediating
adenosine A1 receptor effects on phospholipase C activation (both direct and
synergistic) by transiently transfecting CHO-A1 cells with a scavenger of
Gbetagamma subunits: the C-terminus of beta-adrenoceptor kinase 1 (beta ark1
residues 495-689). [3H]inositol phosphate responses to the selective adenosine A1
receptor agonist N6-cyclopentyladenosine (CPA; 1 microM) were inhibited (41 +/-
1%) in CHO-A1 cells transiently transfected with the Gbetagamma scavenger, beta
ark1 (495-689). Expression of beta ark1 (495-689) protein was confirmed by
Western blotting. In contrast, adenosine A1 receptor-mediated inhibition of
forskolin stimulated [3H]cyclic AMP accumulation was unaffected by transient
expression of beta ark1 (495-689). Beta ark1 (495-689) expression had no
significant effect on the [3H]inositol phosphate responses produced by activation
of the endogenous P2Y2 purinoceptor (100 microM UTP; 92 +/- 0.8% of control).
[3H]inositol phosphate accumulation in response to adenosine A receptor
activation was also attenuated in CHO-K1 cells co-transfected with the beta ark1
(495-689) minigene (59 +/- 4% inhibition of control response to 1 microM CPA).
Finally, transient expression of beta ark1 (495-689) in CHO-A1 cells inhibited
the augmentation of [3H]inositol phosphate responses resulting from co-activation
of adenosine A1 receptors and P2Y2 purinoceptors. These experiments indicate that
Gbetagamma subunits are involved in the direct coupling the adenosine A1 receptor
to phospholipase C and that they also participate in the augmentation of P2Y2
purinoceptor-mediated [3H]inositol phosphate responses by the adenosine A1
receptor.
PMID- 9754943
TI - The 5-HT1A receptor agonist BAY x 3702 prevents staurosporine-induced apoptosis.
AB - The 5-HT1A receptor agonist (-)-(R)-2-[4-[[(3,4-dihydro-2H-1-benzopyran-2
yl)methyl]amino]butyl]-1,2 -benzisothiazol-3(2H)-one1,1-dioxide monohydrochloride
(BAY x 3702) was recently shown to have pronounced neuroprotective effects in rat
models of cerebral ischemia and traumatic brain injury. In the present study we
investigated the neuroprotective effects of BAY x 3702 in primary cultures of
hippocampal and cortical neurons. Cell death was induced by 25 nM of the
apoptosis inducing agent staurosporine and analyzed 24 h later by release of
lactate dehydrogenase, formation of apoptotic bodies and DNA fragmentation. A
significant neuroprotection was seen after pretreatment of the affected neurons
with 50 pM to 1 microM BAY x 3702. The effects of BAY x 3702 were completely
blocked by the selective 5-HT1A receptor antagonist N-(2-(4-(2-methoxyphenyl)-1
piperazinyl)ethyl)-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride) (WAY
100635). These results indicate that low concentrations of BAY x 3702 protect
cortical as well as hippocampal neurons from apoptotic cell death via a 5-HT1A
receptor mediated pathway.
PMID- 9754944
TI - Use of a spreadsheet to quantitate the equilibrium binding of an allosteric
modulator.
AB - Using the program Microsoft EXCEL, a spreadsheet was developed for constrained,
simultaneous analysis of multiple datasets obtained from equilibrium binding
experiments, according to an allosteric model of interaction. This approach was
used to quantitate the interaction between the modulator (heptane-1,7-bis
(dimethyl 3'-phthalimidopropyl) ammonium bromide) (C7/3-phth) and the
radioligands [3H]N-methylscopolamine and [3H]quinuclidinyl benzilate at cortical
and atrial muscarinic receptors. The interaction between various concentrations
of the radioligands and C7/3-phth, in the guinea pig atrium and in the rat
cerebral cortex, could be well described by the allosteric model. The affinity of
C7/3-phth for unoccupied atrial receptors was significantly higher than for
cortical receptors. The negative cooperativity between [3H]quinuclidinyl
benzilate and the modulator was higher in cortex than that between the modulator
and [3H]N-methylscopolamine. It is suggested that the described method has wide
applicability because of the extensive availability of spreadsheet programs, the
analytical advantages offered by constrained, simultaneous nonlinear regression
and the ability to adapt the spreadsheet to almost any model of ligand-receptor
interaction.
PMID- 9754945
TI - No heroin or morphine 6beta-glucuronide analgesia in mu-opioid receptor knockout
mice.
AB - Recent reports suggest that heroin and its metabolite morphine 6beta-glucuronide
can produce analgesia independent of the morphine-preferring mu-opioid receptor.
We have tested heroin and morphine 6beta-glucuronide analgesia in wild-type,
homozygous and heterozygous mu-opioid receptor knockout mice. Homozygotes display
no heroin or morphine 6beta-glucuronide analgesia. Heterozygous mice with one mu
opioid receptor gene copy reveal reduced heroin and morphine 6beta-glucuronide
analgesia. The mu-opioid receptor-dependence of heroin and morphine 6beta
glucuronide fails to support a requirement for a heroin-specific opiate receptor
subtype.
PMID- 9754946
TI - Recent developments in HIV protease inhibitor therapy.
PMID- 9754947
TI - Suppression of recurrent genital herpes simplex virus type 2 infection by Rhus
javanica in guinea pigs.
AB - Rhus javanica has been shown to exhibit anti-herpes simplex virus (HSV) activity
and potentiate the anti-HSV activity of acyclovir in vitro and in vivo. This
extract was examined for its suppressive efficacy on recurrent genital infection
in guinea pigs. Guinea pigs were primarily infected intravaginally with HSV type
2 (HSV-2). Prophylactic oral administration, at the dose corresponding to human
use, of R. javanica significantly reduced the incidence, severity and/or
frequency of spontaneous and severe skin lesions as compared with latently
infected guinea pigs administered with water. This prophylactic efficacy was
confirmed by the crossover administration, for more than 2 months, of R. javanica
and water to the infected guinea pigs. Toxicity, such as weight loss, from R.
javanica administration was not observed in the guinea pigs. When recurrent HSV-2
disease was induced by ultraviolet irradiation 3 months after primary infection,
the prophylaxis with R. javanica was also significantly effective in reducing the
severity of ultraviolet-induced skin lesions. Thus, prophylaxis of recurrent
genital HSV-2 infection with R. javanica may preserve the efficacy of acyclovir
by reducing both the use of acyclovir and the appearance of acyclovir-resistant
viruses.
PMID- 9754948
TI - The antiviral activity of the ribonucleotide reductase inhibitor BILD 1351 SE in
combination with acyclovir against HSV type-1 in cell culture.
AB - BILD 1351 SE is a selective peptidomimetic subunit association inhibitor of the
herpes simplex virus (HSV) ribonucleotide reductase (RR) with potent antiviral
activity both in cell culture assays and animal models of HSV disease. The
ability of BILD 1351 SE to inhibit the replication of HSV-1 when used in
combination with acyclovir (ACV) for the treatment of HSV infections was
investigated in baby hamster kidney cells using a 96-well enzyme-linked
immunosorbent assay. The effective concentrations to achieve 50% inhibition
(EC50) of virus replication by BILD 1351 SE in serum-starved and non serum
starved cells were 2 +/- 0.9 and 4.1 + 1.6 microM, respectively. The EC50 of ACV
under both assay conditions was equal to 2.7 +/- 0.9 microM when tested alone.
However, upon addition of BILD 1351 SE, the antiviral activity of ACV was
potentiated in a synergistic manner as determined by the isobole method. At a
concentration of BILD 1351 SE that produced 30% inhibition of HSV-1 replication,
the EC50 of ACV decreased by about 15-fold in confluent cells and 17-fold in
serum-starved cells. Similar conclusions were reached when evaluating drug
interactions by the median dose-effect. Assuming mutually non-exclusive
conditions at a drug ratio of ACV/BILD 1351 SE of 1/2, synergy was demonstrated
in confluent cells with a drug enhancement index at EC50 of 14 and a combination
index of 0.25. None of the drug combinations tested showed increased cytotoxicity
in comparison with each drug alone. These results are consistent with the
expected mode of action of a selective HSV RR inhibitor and support the strategy
of combining these inhibitors with ACV for improved therapy of HSV infections.
PMID- 9754949
TI - The sequential occurrence of pol 215 and pol 41 zidovudine resistance mutations
is associated in an additive fashion with low CD4 cell counts and high plasma and
cellular HIV viral load.
AB - We report on a cross-sectional study of virological and immunological surrogate
markers of HIV infection in 115 patients for whom a determination of the pol 215
and pol 41 zidovudine (ZDV) resistance mutations had been described between
January 1995 and February 1996. The patients received ZDV alone or a combination
of ZDV and zalcitabine or didanosine. A total of 55, 15 and 45 patients exhibited
a wild (W), a mixed (MIX) or a mutant (M) genotype at codon pol 215,
respectively; 85, 10 and 20 patients exhibited a W, a MIX or a M genotype at
codon pol 41, respectively. Patients exhibiting the pol 215 M genotype had lower
CD4 cells, higher plasma viral load and higher proviral burden than patients
exhibiting the pol 215 W genotype. Patients who had variants exhibiting both pol
215 M and pol 41 M or MIX genotypes had significantly worsened surrogate marker
values than patients having variants only carrying the pol 215 M genotype. These
observations demonstrate that the two mutations additively associate with
pejorative surrogate markers.
PMID- 9754950
TI - Antiviral activity of Viracea against acyclovir susceptible and acyclovir
resistant strains of herpes simplex virus.
AB - Viracea, a topical microbicide, is a blend of benzalkonium chloride and
phytochemicals derived from Echinacea purpurea and is a proprietary formula from
Destiny BioMediX Corp. Viracea was tested against 40 strains of herpes simplex
virus (HSV): 15 strains (five HSV-1 and ten HSV-2) were resistant to acyclovir
(ACV-R) and 25 strains (13 HSV-1 and 12 HSV-2) were susceptible to ACV (ACV-S).
The median ED50 of Viracea for the five ACV-R strains of HSV-1 was a 1:100
dilution of the drug with a range of 1:50-1:400. The median ED50 of Viracea for
the ten ACV-R strains of HSV-2 was 1:200 with a range of 1:50-1:3200. For the ACV
S strains of HSV-1 and HSV-2, the median ED50 of Viracea was 1:100 and 1:200,
respectively. The cytotoxicity of Viracea was evaluated in a standard neutral red
dye uptake assay in human foreskin fibroblasts. The cytotoxicity of Viracea
approached only 50% at the highest concentration of the drug tested, a 1:2
dilution, indicating that Viracea is non-toxic in this cell cytotoxicity assay.
Although the active component(s) in Viracea that has anti-HSV activity is not
known, it appears that this extract has good antiviral activity against both ACV
resistant and ACV susceptible strains of HSV-1 and HSV-2.
PMID- 9754951
TI - Plectin in the human central nervous system: predominant expression at pia/glia
and endothelia/glia interfaces.
AB - Plectin is a high molecular weight protein that serves as a versatile
cytoskeletal cross-linker molecule. Mutations of the human plectin gene have
recently been identified to cause the autosomal recessive disorder epidermolysis
bullosa simplex with muscular dystrophy (EBS-MD). A subgroup of EBS-MD patients
display signs of a neurodegenerative disorder suggesting that the expression of
defective plectin may also interfere with the structural and functional integrity
of the human central nervous system. However, the expression pattern of plectin
in the human brain is still unknown. We therefore analyzed the
immunohistochemical distribution of plectin in normal hippocampal specimens
obtained at autopsy and in neocortical and hippocampal tissue of patients who had
undergone epilepsy surgery. In general, plectin-immunoreactive cells were
identified as capillary endothelia and astrocytes. A striking feature seen in all
specimens was the accentuated plectin immunoreactivity of astrocytic end feet
abutting on blood vessels and on the pial surface. Furthermore, the analysis of
hippocampal tissue of epilepsy patients with Ammon's horn sclerosis (AHS)
revealed a strong plectin labeling of reactive astrocytes. The latter finding
suggests that the up-regulation of plectin, which parallels the increase of glial
fibrillary acidic protein, may be a general feature of reactive astroglia. The
predominant expression of plectin at pia/glia and endothelia/glia interfaces in
the human brain indicates that plectin may have an integral role in the
structural organization of the blood-brain barrier and the leptomeninges.
PMID- 9754952
TI - Argyrophilic grain disease is associated with apolipoprotein E epsilon 2 allele.
AB - Argyrophilic grain disease (AGD) is a distinct degenerative disorder of the human
brain associated with the formation of abnormally phosphorylated tau protein. AGD
related cytoskeletal changes are known to affect specific subsets of nerve cells
and oligodendrocytes. Here we demonstrate a remarkable association between the
apolipoprotein E (ApoE) epsilon2 allele and AGD. Individuals afflicted with AGD
(n = 48) reveal a significantly higher frequency of the epsilon2 allele compared
with controls (n = 43) (22% versus 4%, P < 0.0002). The association between AGD
and epsilon2 allele of ApoE suggests that AGD can be distinguished from other
neurodegenerative disorders not only neuropathologically, but also genetically.
PMID- 9754953
TI - Apolipoprotein E allele frequencies in argyrophilic grain disease.
AB - Apolipoprotein E (ApoE) genotypes were analyzed in 35 subjects with argyrophilic
grain diseases (AgD). Neuropathologically, all cases were characterized by
abundant argyrophilic grains in the hippocampus and in the entorhinal or
parahippocampal cortex. We found an ApoE epsilon4 allele frequency of 0.007 in
AgD patients, which is significantly different from the epsilon4 allele
frequencies reported in age-matched Alzheimer's disease (AD) patients (0.24), but
not from age-matched controls (0.09). We conclude that the ApoE epsilon4 allele
does not constitute a risk factor for the development of AgD. Our results further
suggest that AgD is a progressive disorder differentiated from AD by
morphological and genetic criteria.
PMID- 9754954
TI - Fiber-type-dependent expression of adenovirus-mediated transgene in mouse
skeletal muscle fibers.
AB - We show the efficient transduction and expression of the lacZ gene in the
skeletal muscle of adult C57BL/10ScSn mice after adenovirus-mediated gene
transfer. Of the myofibers in the tibialis anterior muscle 62% were beta
galactosidase positive after injection of the lacZ gene under the control of the
chicken beta-actin promoter and the cytomegalovirus enhancer. The transduced gene
was preferentially expressed in type IIA and IIX fibers, which were richer in
oxidative enzymes than type IIB fibers.
PMID- 9754955
TI - Bcl-2, Bax and Bcl-x expression in neuronal apoptosis: a study of mutant weaver
and lurcher mice.
AB - We investigated the expression of the apoptosis modulating proteins Bcl-2, Bax
and Bcl-x in the cerebellum of mutant lurcher and weaver mice. Lurcher Purkinje
cells and weaver germinal (granule neuron progenitor) cells both die via
apoptosis during the postnatal cerebellar development. No significant changes in
the expression patterns were detected prior to the actual cell death process.
Instead apoptotic lurcher Purkinje cells exhibited increased Bax and Bcl-x
expression, while surviving cells had an expression pattern similar to that of
healthy littermates. Increased Bax expression was also found in apoptotic weaver
germinal cells, while no change of Bcl-x expression was detected. Bcl-2 was
expressed at low levels in cerebellar neurons and no loss of Bcl-2 was evident.
The observed expression patterns of Bcl-2, Bax and Bcl-x protein in apoptotic
lurcher and weaver neurons support the hypothesis that the execution of neuronal
apoptosis involves increased expression of Bax, which could represent a general
mechanism in diverse neurodegenerative processes.
PMID- 9754956
TI - Murine cytomegalovirus induces apoptosis in non-infected cells of the developing
mouse brain and blocks apoptosis in primary neuronal culture.
AB - Cytomegalovirus (CMV) is the most common cause of congenital infection, resulting
in birth defects such as microcephaly. In this study, we found that apoptosis is
induced in the developing mouse brain infected with murine cytomegalovirus (MCMV)
in an association with neuronal cell loss. With the combination of the terminal
deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) technique
and immunohistochemical staining, 3.8% of the TUNEL-positive cells were double
stained with the antibody to neuron-specific enolase, while none of the TUNEL
positive cells were stained with antibodies to the immediate early and early
viral antigens of MCMV. Furthermore, distribution pattern of the TUNEL-positive
cells was different from that of viral DNA-positive cells detected by the in situ
DNA-DNA hybridization. More than 30% of the TUNEL-positive cells were double
stained with the F4/80 antibody specific for microglia/macrophages, which were
sometimes swollen, presumably the consequence of engulfment of the neuronal
apoptotic cells. In the primary neuronal cultures, MCMV infection inhibited the
induction of apoptosis either by serum deprivation or by glutamate treatment. It
was also confirmed by the double-staining method that apoptosis was not induced
in the viral-infected neuronal cultures. These results suggest that MCMV
infection induces apoptosis in non-infected neuronal cells, presumably by
indirect mechanisms, and that apoptotic cells are engulfed by
microglia/macrophages. The induction and blocking of neuronal apoptosis by viral
infection may be important for morphological and functional brain disorders in
the congenital CMV infection.
PMID- 9754957
TI - Astrocytic pathology in progressive supranuclear palsy: significance for
neuropathological diagnosis.
AB - Progressive supranuclear palsy (PSP) is known to have tau-positive cytoskeletal
abnormalities in astrocytes and oligodendroglia as well as neurons. Astrocytic
tau-positive structures (tuft-shaped astrocytes; Tu-SA) were studied to elucidate
their proper significance in the neuropathological diagnosis of PSP. The
distribution and incidence of Tu-SA were examined in 26 cases of PSP. The disease
specificity of Tu-SA was demonstrated by comparison with diseases accompanied by
neurofibrillary tangles (NFTs) and those with or without cytoskeletal
abnormalities other than NFTs. In PSP, Tu-SA appeared prominently in the
precentral and premotor cortex (areas 4 and 6) of the superior and middle frontal
gyri, but were quite scare in the temporal lobe and limbic area. In the
subcortical nuclei, they appeared preferentially in the putamen and were also
scattered in other degenerating regions. In the cerebrum the Tu-SA and NFTs were
distributed in quite different regions. The assessment of the incidence of Tu-SA
in area 6 revealed that only 5 of 26 PSP cases lacked Tu-SA in the examined
fields. In contrast, in the control diseases, Tu-SA were found only rarely in
cases of corticobasal degeneration in the cerebral cortex among other frequent
tau-positive structures. One case of Pick's disease showed occasional Tu-SA but
only in the hippocampal region and not in the frontal lobe or putamen. In
summary, although the absence of Tu-SA does not necessarily exclude the
possibility of PSP, Tu-SA in the frontal lobe and putamen is highly suggestive
for PSP. Thus, detection of Tu-SA and the ranking of the characteristic
distribution of NFTs contribute to the neuropathological diagnosis of PSP.
PMID- 9754958
TI - Presenile Alzheimer dementia characterized by amyloid angiopathy and large
amyloid core type senile plaques in the APP 692Ala-->Gly mutation.
AB - Mutations at codons 717 and 670/671 in the amyloid precursor protein (APP) are
rare genetic causes of familial Alzheimer's disease (AD). A mutation at codon 693
of APP has also been described as the genetic defect in hereditary cerebral
hemorrhage with amyloidosis of the Dutch type (HCHWA-D). We have reported a
APP692Ala-->Gly (Flemish) mutation as a cause of intracerebral hemorrhage and
presenile dementia diagnosed as probable AD in a Dutch family. We now describe
the post-mortem examination of two demented patients with the APP692 mutation.
The neuropathological findings support the diagnosis of AD. Leptomeningial and
parenchymal vessels showed extensive deposition of Abeta amyloid protein.
Numerous senile plaques consisted of large Abeta amyloid cores, often measuring
more than 30 microm in diameter and were surrounded by a fine meshwork of
dystrophic neurites. In addition, there were a large number of paired helical
filaments in pyramidal neurons and dystrophic neurites. Our findings show that
the APP692 mutation leads to morphological abnormalities that are similar to AD,
but the morphology of senile plaques is clearly distinct from that described in
sporadic and chromosome 14-linked AD patients, in patients with APP717 mutations
causing familial, presenile AD and in patients with the APP693 mutation causing
HCHWA-D.
PMID- 9754959
TI - Ultrastructural and permeability features of microvessels in the olfactory bulbs
of SAM mice.
AB - The ultrastructural features of microvessels showing increased permeability to
intravenously injected horseradish peroxidase (HRP) were examined in the
olfactory bulbs of senescence-accelerated prone mice (SAMP8), which showed age
related deficits in learning and memory, and senescence-accelerated resistant
mice (SAMR1), which did not show the age-related deficits. HRP was visualized
with tetramethyl benzidine (TMB) and diaminobenzidine (DAB) for light and
electron microscopic examination, respectively. In the olfactory bulbs of 13
month-old SAMP8 mice, the staining reaction with TMB for HRP appeared in the
neuropil of central area (granule cell layer and subependymal layer), in the pia
mater and in the vascular wall. Some vessels located in the central area showed
several changes observed at the ultrastructural level. The cytoplasm of the
endothelial cells, especially in the arterioles, was segmentally thickened and
contained numerous vesicles and vacuoles, some of which were HRP positive. The
endothelial cell surface was occasionally undulated with microvillous
protrusions. Membranous inclusions within the basal lamina, suggesting the
cellular (presumably pericytal) degeneration, were frequently observed,
especially in venules. The collagen deposits were occasionally observed in the
subendothelial space of some vessels. Perivascular cells with vacuolated
inclusions or lipid-like droplets were present around some vessels in the central
area of the olfactory bulbs of aged SAMP8 mice. On the other hand, in the
microvessels located in the areas negative for HRP-TMB reaction, except the
vessel walls, the cytoplasm of the endothelial cells with smooth luminal surface
was flattened and some vesicles located there contained HRP-DAB reaction product.
Weak staining reaction with TMB for HRP appeared also in the central area of the
olfactory bulbs of 3-month-old SAMP8 mice and 3- and 13-month-old SAMR1 mice. The
cytoplasm of the endothelial cells in the olfactory bulbs of these mice was
focally thickened and contained some cytoplasmic vesicles. Occasionally, the
endothelial cell surface was moderately undulated with few microvillous
protrusions. Membranous inclusions within the basal lamina were not observed in
these animals. These findings indicate that the endothelial cells and pericytes
in some vessels located in the central area of the olfactory bulb of aged SAMP8
mice, which show staining reaction with TMB for HRP, are ultrastructurally
changed, suggesting their altered functions.
PMID- 9754960
TI - Reappraisal of progressive multifocal leukoencephalopathy due to simian virus 40.
AB - Several cases of progressive multifocal leukoencephalopathy (PML) have been
associated with simian virus 40 (SV40), rather than with JC virus (JCV), the
polyomavirus originally isolated from PML tissue. PML has, therefore, been
defined as a demyelinating syndrome with possible multiple viral etiologies.
Tissues from three of the cases thought to be associated with SV40 were available
for reexamination. Monoclonal antibodies specific for SV40 capsid antigen VPI,
virus-specific biotinylated DNA probes for in situ hybridization, and virus
specific primers in the polymerase chain reaction (PCR) were used. Macaque PML
brain served as a positive control tissue for SV40 brain infection. Monoclonal
antibodies to SV40 VPI failed to recognize viral antigen in lesions from all
three human PML cases. The biotinylated DNA probe, which reacted with SV40 in
macaque PML, failed to detect SV40 in human PML. However, JCV could be detected
by in situ hybridization with a JCV-specific DNA probe. Moreover, JCV DNA
sequences were amplified by PCR from the human PML tissues, whereas SV40 DNA
sequences were amplified only from the macaque brain. Thus, we could not confirm
the original reports that the demyelinating agent in these three cases of PML was
SV40, rather than JCV. We conclude that SV40 infection of the central nervous
system need not be ruled out in the differential diagnosis of PML.
PMID- 9754961
TI - Mitochondrial dysfunction induced by oxidative stress in the brains of hamsters
infected with the 263 K scrapie agent.
AB - Scrapie, one of the prion diseases, is a transmissible neurodegenerative disease
of sheep and other animals. Clinical symptoms of prion diseases are characterized
by a long latent period, followed by progressive ataxia, tremor, and death. To
study the induction of neurodegeneration during scrapie infection, we have
analyzed the activities of various antioxidant enzymes and mitochondrial enzymes
in cerebral cortex, brain stem, and cerebellum of scrapie-infected hamsters. The
activity of mitochondrial Mn-superoxide dismutase (SOD) was decreased, while the
activities of cytosolic Cu/Zn-SOD and catalase were not altered in infected
brains. The activities of glutathione peroxidase and glutathione reductase were
increased in scrapie-infected hamsters. The decreased activity of Mn-SOD might
result in increasing oxidative stress in the mitochondria of infected brain; this
concept is supported by our findings of a high level of lipid peroxidation, and
low levels of ATPase and cytochrome c oxidase activity in the infected cerebral
mitochondria. In addition, structural abnormalities of mitochondria have been
observed in the neurons of hippocampus and cerebral cortex of infected brain.
These results suggest that mitochondrial dysfunction caused by oxidative stress
gives rise to neurodegeneration in prion disease.
PMID- 9754962
TI - Complement C1-inhibitor expression in Alzheimer's disease.
AB - In situ and in vitro studies suggest that activation of locally produced
complement factors may act as a mediator between amyloid deposits and
neurodegenerative changes seen in Alzheimer's disease (AD). C1-esterase inhibitor
(C1-Inh), which regulates activation of C1 of the complement classical pathway,
can be detected immunohistochemically in its inactivated form in activated
astrocytes and dystrophic neurites in AD plaque areas. In this study, designed to
investigate the cellular source of C1-Inh, C1-Inh was found to be secreted in a
functionally active form by astrocytes cultured from postmortem human brain
specimens as well as by neuroblastoma cell lines. Recombinant human interferon
gamma (IFN-gamma), which stimulates C1-Inh synthesis in various cell types,
several-fold stimulated C1-Inh protein secretion by cultured human astrocytes
derived from different regions of the central nervous system and by one (SK-N-SH)
of two neuroblastoma cell lines (SK-N-SH and IMR-32) included in this study. In
contrast to IFN-gamma, other cytokines [interleukin (IL)-1beta, IL-6 and tumor
necrosis factor (TNF)-alpha] that can be found in brain areas affected by AD, did
not stimulate C1-Inh secretion by astrocytes or neuroblastomas in vitro. This
inability to secrete C1-Inh is probably due to unresponsiveness at the
transcriptional level, since C1-Inh secretion paralleled the expression of the
2.1-kb C1-Inh mRNA. In situ hybridization with a C1-Inh RNA antisense probe
labeled neurons rather than astrocytes, suggesting a role for neurons as
producers of complement regulatory proteins in vivo. Since IFN-gamma is
apparently lacking in the brain parenchyma, and amyloid plaque-associated
cytokines (IL-1beta, IL-6, TNF-alpha) do not stimulate C1-Inh expression in
vitro, the nature of the stimulus responsible for neuronal C1-Inh expression in
AD brains remains to be investigated.
PMID- 9754963
TI - Polyneuropathy with endoneurial immune complex deposition as the first
manifestation of systemic lupus erythematosus.
AB - A 72-year-old male presented with progressive sensorimotor polyneuropathy. Later
weight loss, proteinuria and deteriorating renal function were noted. The
electrophysiological examinations revealed extensive, symmetrical demyelinating
and axonal polyneuropathy. Frozen sections obtained from sural nerve biopsy
sample showed the presence of immune complexes and complements in the walls of
the epi- and endoneurial blood vessels, and perineurium suggestive of systemic
lupus erythematous (SLE). IgG and Clq deposits were also present along the
basement membranes of Schwann cells. The electron microscopy confirmed the
presence of immune complex deposition. Diagnosis of SLE was proven by positive
serology (anti-nuclear antibodies, anti-Sm, anti-RNP, anti-double-stranded DNA)
and renal biopsy showing membranous lupus nephritis with extensive immune complex
deposition in the tubular basement membranes. Despite combined immunosuppressive
treatment for 10 months, the patient died of complications of generalized immune
complex vasculitis. The manifestation of SLE in elderly patients, especially in
males, is very rare. Moreover, the polyneuropathy is an unusual initial symptom
of SLE. Immune complex deposition in Schwann cell basement membrane probably
plays an important role in the pathomechanism of sensorimotor polyneuropathy in
SLE.
PMID- 9754964
TI - Retroperitoneal ectopic neural mass: "abdominal brain"--presentation of two cases
and proposal of classification of paraneuraxial neural ectopia.
AB - An encapsulated mass of brain tissue was found in the retroperitoneum of a fetus
of gestational week 15 and a boy of age 3 years. The masses possessed fibrous
tissue that bound them to the spine and intraspinal connective tissue,
respectively, but there was no evidence of direct continuity of the ectopic brain
tissue with the normal central nervous system. There was no dysraphism. In our
fetal case, possible Foix-Alajouanine anomaly was additionally found. The ectopic
neural tissue in the retroperitoneal region may be termed "abdominal brain." In
the literature, an identical state has been described in the head (paracranial
region) but there are no other records of the paraspinal region. Despite the
different locations of the masses (head/paracranial or
retroperitoneum/paraspinal), these ectopic brain masses should belong to the same
disorder spectrum of the paraneuraxial neural ectopia, a new concept.
PMID- 9754965
TI - Beta-galactosidase deficiency in a Korat cat: a new form of feline GM1
gangliosidosis.
AB - A 7-month-old Korat cat was referred for a slowly progressive neurological
disease. Circulating monocytes and lymphocytes showed the presence of single or
multiple empty vacuoles and blood leukocytes enzyme assay revealed a very low
beta-galactosidase activity level (4.7 nmol/mg per h) as compared to unaffected
parents and relatives. Histologically, the cat, euthanized at the owner request
at 21 months of age, presented diffuse vacuolization and enlargement of neurons
throughout the brain, spinal cord and peripheral ganglia, severe cerebellar
neuronal cell loss, and moderate astrocytosis. Stored material was stained with
periodic acid-Schiff on frozen sections and with the lectins Ricinus conmmunis
agglutinin-I, concanavalin A and wheat germ agglutinin on paraffin-embedded
sections. Ultrastructurally, neuronal vacuoles were filled with concentrically
whorled lamellae and small membrane-bound vesicles. In the affected cat, beta
galactosidase activity was markedly reduced in brain (18.9%) and liver (33.25%),
while total beta-hexosaminidase activity showed a remarkable increase.
Quantitation of total gangliosides revealed a 3-fold increase in brain and 1.7
fold in liver of affected cat. High-performance thin layer chromatography (HPTLC)
detected a striking increase of GM1-ganglioside. On densitometric analysis of
HPTLC bands, the absorption of GM1-ganglioside band was 98.52% of all stained
bands (GD1a, GD1b, GT1b). Based on clinical onset, morphological and
histochemical features, and biochemical findings, the Korat cat GM1
gangliosidosis is comparable with the human type II (juvenile) form. However,
clinical progression, survival time and level of beta-galactosidase deficiency do
not completely fit with those of human type II GM1-gangliosidosis. The disease in
the Korat cat is also different from other reported forms of feline GM1
gangliosidosis.
PMID- 9754966
TI - Relationship between mechanomyogram signals and changes in force of human
forefinger flexor muscles during voluntary contraction.
AB - In previous studies on mechanomyogram (MMG) signals no analysis of these signals
accompanying force generation has been performed. Therefore, we have recorded MMG
signals (previously referred to as muscle sound or acoustomyographic signals)
during voluntary contractions of forefinger flexor muscles in 31 young subjects.
These subjects made contractions to produce force records of triangular or
trapeziform shape. The peak target force amounted to 10, 20 or 40 N which
represented less than 40% of maximal voluntary contraction. The MMG signals
during the transient phases of force generation at three different rates were
analysed. The MMG intensity level calculated for MMG records and the peak-to-peak
amplitude of MMG signals correlated with both the velocity of force increase and
the contraction force. The occurrence of the strongest MMG signals corresponded
to changes in contractile force. Therefore, it is suggested that measurements of
these parameters could be a useful tool in studies of changes in contractile
force.
PMID- 9754967
TI - Mechanomyogram from the different heads of the quadriceps muscle during
incremental knee extension.
AB - To investigate the time- and frequency-domain responses of mechanomyograms (MMGs)
during the progressive fatigue induced by intermittent incremental contractions,
a surface MMG was obtained from the three muscle heads of the quadriceps muscle
in seven subjects while they performed isometric knee extensions lasting 7.6 min.
Isometric intermittent incremental contractions started at 1% of the maximal
voluntary contraction (MVC) for 3 s, with a 3-s relaxation period in between each
contraction, and the contraction level was increased by 1% of MVC for every
contraction (by 10% of MVC per min) up to exhaustion. Separate contractions with
sufficient rest periods were also conducted to serve for the MMG characteristics
without fatigue. The integrated MMG (iMMG) was linearly related to force in all
of the muscles when fatigue was not involved. With regard to the incremental
contractions, the relationship exhibited an ascending-descending shape, but the
behavior was not the same for the individual muscle heads, especially for the
rectus femoris muscle. A steep increase in the median frequency of MMG from
around 60% of MVC corresponded to a decrease in iMMG. These results suggest that
analysis of MMG in the time- and frequency-domain during an incremental protocol
is a useful way of characterizing the motor unit recruitment strategy and fatigue
properties of individual muscles.
PMID- 9754968
TI - Regional blood flow in conscious rats after head-down suspension.
AB - Exposure to microgravity in humans causes cardiovascular deconditioning affecting
blood pressure, heart rate and vascular responsiveness. This study investigated
cardiac output, arterial blood pressure and regional blood flows [radioactive
microspheres: 57Co, 15.5 (SEM 0.1) microm in diameter] in conscious and freely
moving rats subjected to 14 days of simulated microgravity (head-down suspension,
HDS) in male Wistar rats: control (horizontally attached, n = 7), suspended for
14 days (n = 8) and suspended/allowed to recover for 10 min (R10min, n = 5) or 24
h (n = 9). Compared to the control group, 14 days of HDS resulted in reduced
total peripheral resistance (37%); an increased cardiac index (65%) was
associated with no significant change in the mean arterial pressure BPa. There
were elevated brain (63%), visceral (> 20%), hindlimb (> 80%) and forelimb (>
215%) muscle blood flows. In the R10min group, the BPa decreased (18%) and the
regional blood flows returned to control values. Within 24 h the BPa as well as
cardiac index and total peripheral resistance were restored. In conclusion, 14
days of HDS engendered local circulatory changes resulting in transient blood
pressure instability during recovery.
PMID- 9754969
TI - Influence of bright light exposure for several hours during the daytime on
cutaneous vasodilatation and local sweating induced by an exercise heat load.
AB - The aim of the present study was to investigate the effect of exposure to
differing light intensities for several hours during the daytime on the cutaneous
vasodilatation and local forearm sweat rate induced by exercise. Seven healthy
female subjects were exposed to bright light of 6000 lux (bright) or dim light of
100 lux (dim) during the daytime between 0900 hours to 1330 hours, followed by
exposure to 150 lux until the test was over at 1600 hours. They spent their time
in neutral conditions (29 degrees C, 40% relative humidity) from 0900 hours to
1500 hours, and then exercised on a cycle ergometer for 30 min at 50% maximal
physical work capacity. Average tympanic temperatures were significantly lower in
bright than in dim from 1133 hours to 1430 hours. The onset of cutaneous
vasodilatation and local forearm sweating occurred at significantly lower
tympanic temperature (Tty) during exercise after bright than after dim. After
exercise, the cessation of forearm sweating and the rapid change of skin blood
flow occurred at significantly lower Tty after bright than after dim. It was
concluded that exposure to bright light over several hours during the daytime
could reduce Tty and shift the threshold Tty for cutaneous vasodilatation and
forearm sweating to a lower level.
PMID- 9754970
TI - Energy and substrate metabolism during a 42-day bed-rest in a head-down tilt
position in humans.
AB - Microgravity-induced changes in body composition (decrease in muscle mass and
increase in fat mass) and energy metabolism were studied in seven healthy male
subjects during a 42-day bed-rest in a head-down tilt (HDT) position. Resting
energy expenditure (REE), fat and glucose oxidation were estimated by indirect
calorimetry on days 0, +8 and +40 of the HDT period. Assessments were performed
both in post-absorptive conditions and following two identical test meals given
at 3-h intervals. Body composition (dual x-ray absorptiometry) was measured on
days 0, +27, +42. Mean post-absorptive lipid oxidation decreased from 53 (SEM 8)
mg x min(-1) (day 0) to 32 (SEM 10) mg x min(-1) (day 8, P = 0.04) and 36 (SEM 8)
mg x min(-1) (day 40, P = 0.06). Mean post-absorptive glucose oxidation rose from
126 (SEM 15) mg x min(-1) (day 0) to 164 (SEM 14) mg x min(-1) (day 8, P = 0.04)
and 160 (SEM 20) mg x min(-1) (day 40, P = 0.07). Mean fat-free mass (FFM)
decreased between days 0 and 42 [58.0 (SEM 1.8) kg and 55.3 (SEM 1.7) kg, P <
0.01] while fat mass increased without reaching statistical significance. The
mean REE decreased from 1688 (SEM 50) kcal x day(-1) to 1589 (SEM 42) kcal x day(
1) (P = 0.056). Changes in REE were accounted for by changes in FFM. Mean energy
intake decreased from 2532 (SEM 43) kcal x day(-1) to 2237 (SEM 50) kcal x day(
1) (day 40, P < 0.01) with only a minor decrease in the proportion of fat. We
concluded that changes in fat oxidation at the whole body level can be found
during HDT experiments. These changes were related to the decrease in FFM and
could have promoted positive fat balance hence an increase in fat mass.
PMID- 9754971
TI - Electromyogram as an indicator of neuromuscular fatigue during incremental
exercise.
AB - This study analysed the changes in the electromyographic activity (EMG) of the
vastus lateralis muscle (VL) during an incremental maximal oxygen uptake test on
a treadmill. A breakpoint in the integrated electromyogram (iEMG)-velocity
relationship has already been interpreted in two ways: either as a sign of
neuromuscular fatigue or as an expression of the iEMG-velocity relationship
characteristics. The aim of this study was to test a method of distinguishing
fatigue effects from those due to increases in exercise power. Eight well-trained
male runners took part in the study. They completed a running protocol consisting
of 4-min stages of increments in power output. Between each stage (about 15 s
after the start of a minute at rest), the subjects had to maintain a standard
effort: a 10-s isometric leg extension contraction [50% isometric maximal
voluntary contraction (IMVC)]. The EMG was recorded during the running and
isometric protocols, a change in the EMG signal during the isometric exercise
being considered as the sign of fatigue. The iEMG-velocity relationships were
strongly fitted by a second-order polynomial function for data taken at both the
start (r = 0.98) and the end (r = 0.98) of the stage. Based on the stability of
the 50%IMVC-iEMG relationship noted between stages, the start-iEMG has been
identified as expressing the iEMG-velocity relationship without fatigue. The
stage after which end-iEMG increased significantly more steeply than start-iEMG
was considered as the iEMG threshold and was simultaneous with the ventilatory
equivalent for carbon dioxide threshold. The parallel changes of minute
ventilation and iEMG would suggest the existence of common regulation stimuli
linked either to effort intensity and/or to metabolic conditions. The fall in
intracellular [K+] has been discussed as being one of the main factors in
regulating ventilation.
PMID- 9754972
TI - A comparison of physiological responses and rating of perceived exertion between
high-impact and low-impact aerobic dance sessions.
AB - The aim of this study was to compare the exercise intensity and rating of
perceived exertion (RPE) of a high-impact (HIP) and a low-impact (LIP) university
aerobic dance session. Ten women [mean (SD) age 22.9 (2.6) years] took part in
the study. An incremental treadmill test was performed by each subject to
determine maximum oxygen consumption (VO2max) and maximum heart rate (HRmax). The
measured VO2max [mean (SD)] was 49.0 (7.5) ml x kg(-1) x min(-1). The subjects
were randomly assigned to LIP and HIP sessions (i.e. five of the subjects
participated in the HIP session first, and the other five participated in the LIP
session first). In a laboratory, heart rate, oxygen uptake and RPE were measured
throughout each session for each subject. Expired air was collected continuously
throughout the sessions using Douglas bags (ten bags over a 30-min period). The
sessions consisted of 20 min of aerobic exercise (bags 1-7) followed by 5 min of
local muscular endurance exercise (bags 8 and 9) and 5 min of flexibility
exercises (bag 10). The mean intensity of the aerobic section of the LIP and HIP
sessions was 51.6% and 64.7% VO2max, respectively. Ninety-five percent confidence
intervals for the average difference between the HIP and LIP sessions demonstrate
that the %VO2max was between 12% and 14% higher for the HIP session. The mean
%HRmax for the LIP and HIP sessions was 71.4% and 76.7%, respectively, with the
%HRmax in the HIP session being between 5.4% and 7.2% higher on average than that
of the LIP session. On average, the RPE for the aerobic section of the HIP
session (12.1) was consistently higher than that of the LIP session (11.1). HIP
activity has the potential to maintain/improve the aerobic fitness of its
participants. According to the literature, the exercise intensity elicited by LIP
activity may have a limited training effect for the population utilised in this
study, and for some individuals may result in detraining. Conversely, LIP
activities may be an appropriate mode of exercise for overweight and unfit
individuals.
PMID- 9754973
TI - Transient oxygen uptake response to exercise characterizes functional capacity of
the cardiocirculatory system in patients with chronic heart failure: a random
stimulus approach.
AB - The transient response of oxygen uptake (VO2) to submaximal exercise, known to be
abnormal in patients with cardiovascular disorders, can be useful in assessing
the functional status of the cardiocirculatory system, however, a method for
evaluating it accurately has not yet been established. As an alternative approach
to the conventional test at constant exercise intensity, we applied a random
stimulus technique that has been shown to provide relatively noise immune
responses of system being investigated. In 27 patients with heart failure and 24
age-matched control subjects, we imposed cycle exercise at 50 W intermittently
according to a pseudo-random binary (exercise-rest) sequence, while measuring
breath-by-breath VO2. After determining the transfer function relating exercise
intensity (W) to VO2 and attenuating the high frequency ranges (> 6 exercise-rest
cycles x min(-1)), we computed the high resolution band-limited (0-6 cycles x
min(-1)) VO2 response (0-120 s) to a hypothetical step exercise. The VO2 response
showed a longer time constant in the patients than in the control subjects [47
(SD 37) and 31 (SD 8) s, respectively, P < 0.05]. Furthermore, the amplitude of
the VO2 response after the initial response was shown to be significantly smaller
in the patients than in the control subjects [176 (SD 50) and 267 (SD 54) ml x
min(-1) at 120 s]. The average amplitude over 120 s correlated well with peak VO2
(r = 0.73) and deltaVO2/deltaW (r = 0.70), both of which are well-established
indexes of exercise tolerance. The data indicated that our band-limited VO2 step
response using random exercise was more markedly attenuated and delayed in the
patients with heart failure than in the normal controls and that it could be
useful in quantifying the overall functional status of the cardiocirculatory
system.
PMID- 9754974
TI - Effect of increasing running velocity on electroencephalogram in a field test.
AB - This study was designed to measure the electroencephalogram (EEG) after exercise
with increasing intensity. In a field test with increments in running velocity a
2-min EEG was recorded, together with blood lactate concentration and heart rate,
after each stage. An individual protocol was used, with up to six stages of
running to ensure comparability of exercise intensity among the subjects, in each
of 19 athletes (17 men, 2 women) experienced in leisure-time running. The
exercise consisted initially of three running stages of aerobic exercise
intensity without blood lactate accumulation followed by stages with an increase
of lactate concentration. The protocol of the field test led to a progressive
increase in cortical activity directly after the stages without blood lactate
accumulation mainly in the delta frequency band, followed by theta and alpha-1
frequency band, and less pronounced in the alpha-2 and in the beta frequency
bands. After the stages with an onset and further increase of blood lactate
accumulation significant decreases in the beta-2, beta-1 and alpha-1 frequency
bands occurred predominantly in temporal (T3, T4, T5, and T6) and occipital (O1,
and O2) electrode positions, indicating a stage-by-stage decrease of activity.
This decrease may be explained by feed-back from working muscle, via afferents to
the cortex from intero- and proprio-receptors and affective processes. This could
suggest that through a higher running intensity indicated by an onset of blood
lactate accumulation metabolic and mechanical changes led to alterations within
the afferent systems influencing the level of cortical activity.
PMID- 9754975
TI - Dynamic calibration of mechanically, air- and electromagnetically braked cycle
ergometers.
AB - In this study we measured the accuracy of the following types of cycle ergometer
against the criterion of a dynamic calibration rig (DCR): 35 friction-braked
(Monark), 5 research-grade air-braked (Repco) and 5 electromagnetically braked (2
Siemens, 1 Elema-Schonander, 1 Ergoline, 1 Warren E. Collins). Monark ergometer
power outputs over the range 58.9-353.2 W significantly (P < 0.001)
underestimated those registered by the DCR with mean accuracies of 91.7-97.8%.
The least accurate individual reading for each of the six up-scale (0-353.2 W)
power outputs ranged from 81.6 to 91.6%; corresponding down-scale (353.2-0 W)
accuracies were 85.1-92.5%. A hysteresis effect was furthermore evident for this
ergometer in that up-scale measurements were significantly (P < 0.05) greater
than down-scale ones. In addition, when the oldest [mean (SD): 11.3 (2.3) years
old] and newest [1.4 (0.8) years old] eight ergometers were compared, the latter
were significantly (P < 0.05) more accurate over the range 117.7-294.3 W. Apart
from the two lowest power outputs of 47 W (62.2-96.0% accuracy) and 127 W (88.0
97.7% accuracy), the individual up-scale and down-scale accuracies of the Repco
ergometers ranged from 98.0 to 104.2% for power outputs of 272.7-1137.8 W and the
means were not significantly different from those of the DCR. There was also no
evidence of hysteresis. Except for the initial power output of 50 W (40 rev/min:
83.8-99.2% accuracy; 60 rev/min: 93.2-122.6% accuracy), the individual accuracies
of the electromagnetically braked ergometers ranged from 89.3 to 101.4% over the
up-scale range of 100-400 W, and none of the means were significantly different
from those of the DCR. The variability of individual errors for the preceding
data emphasises that all cycle ergometers should be validated against the
criterion of a DCR if accurate power outputs are required.
PMID- 9754976
TI - Brain temperature and limits on transcranial cooling in humans: quantitative
modeling results.
AB - Selective brain cooling (SBC) of varying strengths has been demonstrated in a
number of mammals and appears to play a role in systemic thermoregulation.
Although primates lack obvious specialization for SBC, the possibility of brain
cooling in humans has been debated for many years. This paper reports on the use
of mathematical modeling to explore whether surface cooling can control
effectively the temperature of the human cerebrum. The brain was modeled as a
hemisphere with a volume of 1.33 1 and overlying layers of cerebrospinal fluid,
skull, and scalp. Each component was assigned appropriate dimensions, physical
properties and physiological characteristics that were determined from the
literature. The effects of blood flow and of thermal conduction were modeled
using the steady-state form of the bio-heat equation. Input parameters included
core (arterial) temperature: normal (37 degrees C) or hyperthermic (40 degrees
C), air temperature: warm (30 degrees C) or hot (40 degrees C), and sweat
evaporation rate: 0, 0.25, or 0.50 l x m(-2) x h(-1). The resulting skin
temperatures of the model ranged from 31.8 degrees C to 40.2 degrees C, values
which are consistent with data obtained from the literature. Cerebral
temperatures were generally insensitive to surface conditions (air temperature
and evaporation rate), which affected only the most superficial level of the
cerebrum (< or =1.5 mm) The remaining parenchymal temperatures were 0.2-0.3
degrees C above arterial temperatures, regardless of surface conditions. This
held true even for the worst-case conditions combining core hyperthermia in a hot
environment with zero evaporative cooling. Modeling showed that the low surface
to-volume ratio, low tissue conductivity, and high rate of cerebral perfusion
combine to minimize the potential impact of surface cooling, whether by
transcranial venous flow or by conduction through intervening layers to the skin
or mucosal surfaces. The dense capillary network in the brain assures that its
temperature closely follows arterial temperature and is controlled through
systemic thermoregulation independent of head surface temperature. A review of
the literature reveals several independent lines of evidence which support these
findings and indicate the absence of functionally significant transcranial venous
flow in either direction. Given the fact that humans sometimes work under
conditions which produce face and scalp temperatures that are above core
temperature, a transcranial thermal link would not necessarily protect the brain,
but might instead increase its vulnerability to environmentally induced thermal
injury.
PMID- 9754977
TI - Implications of moderate altitude training for sea-level endurance in elite
distance runners.
AB - Elite distance runners participated in one of two studies designed to investigate
the effects of moderate altitude training (inspiratory partial pressure of oxygen
approximately 115-125 mmHg) on submaximal, maximal and supramaximal exercise
performance following return to sea-level. Study 1 (New Mexico, USA) involved 14
subjects who were assigned to a 4-week altitude training camp (1500-2000 m)
whilst 9 performance-matched subjects continued with an identical training
programme at sea-level (CON). Ten EXP subjects who trained at 1640 m and 19 CON
subjects also participated in study 2 (Krugersdorp, South Africa). Selected
metabolic and cardiorespiratory parameters were determined with the subjects at
rest and during exercise 21 days prior to (PRE) and 10 and 20 days following
their return to sea-level (POST). Whole blood lactate decreased by 23% (P < 0.05
vs PRE) during submaximal exercise in the EXP group only after 20 days at sea
level (study 1). However, the lactate threshold and other measures of running
economy remained unchanged. Similarly, supramaximal performance during a
standardised track session did not change. Study 2 demonstrated that hypoxia per
se did not alter performance. In contrast, in the EXP group supramaximal running
velocity decreased by 2% (P < 0.05) after 20 days at sea-level. Both studies were
characterised by a 50% increase in the frequency of upper respiratory and
gastrointestinal tract infections during the altitude sojourns, and two male
subjects were diagnosed with infectious mononucleosis following their return to
sea-level (study 1). Group mean plasma glutamine concentrations at rest decreased
by 19% or 143 (74) microM (P < 0.001) after 3 weeks at altitude, which may have
been implicated in the increased incidence of infectious illness.
PMID- 9754978
TI - Detection of the change point in oxygen uptake during an incremental exercise
test using recursive residuals: relationship to the plasma lactate accumulation
and blood acid base balance.
AB - The purpose of this study was to develop a method to determine the power output
at which oxygen uptake (VO2) during an incremental exercise test begins to rise
non-linearly. A group of 26 healthy non-smoking men [mean age 22.1 (SD 1.4)
years, body mass 73.6 (SD 7.4) kg, height 179.4 (SD 7.5) cm, maximal oxygen
uptake (VO2max) 3.726 (SD 0.363) l x min(-1)], experienced in laboratory tests,
were the subjects in this study. They performed an incremental exercise test on a
cycle ergometer at a pedalling rate of 70 rev x min(-1). The test started at a
power output of 30 W, followed by increases amounting to 30 W every 3 min. At 5
min prior to the first exercise intensity, at the end of each stage of exercise
protocol, blood samples (1 ml each) were taken from an antecubital vein. The
samples were analysed for plasma lactate concentration [La]pl, partial pressure
of O2 and CO2 and hydrogen ion concentration [H+]b. The lactate threshold (LT) in
this study was defined as the highest power output above which [La-]pl showed a
sustained increase of more than 0.5 mmol x l(-1) x step(-1). The VO2 was measured
breath-by-breath. In the analysis of the change point (CP) of VO2 during the
incremental exercise test, a two-phase model was assumed for the 3rd-min-data of
each step of the test: Xi = at(i) + b + epsilon(i) for i = 1,2, ..., T, and E(Xi)
> at(i) + b for i = T + 1, ..., n, where X1, ..., Xn are independent and
epsilon(i) approximately N(0, sigma2). In the first phase, a linear relationship
between VO2 and power output was assumed, whereas in the second phase an
additional increase in VO2 above the values expected from the linear model was
allowed. The power output at which the first phase ended was called the change
point in oxygen uptake (CP-VO2). The identification of the model consisted of two
steps: testing for the existence of CP and estimating its location. Both
procedures were based on suitably normalised recursive residuals. We showed that
in 25 out of 26 subjects it was possible to determine the CP-VO2 as described in
our model. The power output at CP-VO2 amounted to 136.8 (SD 31.3) W. It was only
11 W -- non significantly -- higher than the power output corresponding to LT.
The VO2 at CP-VO2 amounted to 1.828 (SD 0.356) l x min(-1) was [48.9 (SD 7.9)%
VO2max]. The [La-]pl at CP-VO2, amounting to 2.57 (SD 0.69) mmol x l(-1) was
significantly elevated (P < 0.01) above the resting level [1.85 (SD 0.46) mmol x
l(-1)], however the [H+]b at CP-VO2 amounting to 45.1 (SD 3.0) nmol x l(-1), was
not significantly different from the values at rest which amounted to 44.14 (SD
2.79) nmol x l(-1). An increase of power output of 30 W above CP-VO2 was
accompanied by a significant increase in [H+]b above the resting level (P =
0.03).
PMID- 9754979
TI - Concomitant inhaled corticosteroid resensitises cardiac beta2-adrenoceptors in
the presence of long-acting beta2-agonist therapy.
AB - OBJECTIVE: The aim of the present study was to evaluate the effects of
concomitant inhaled corticosteroid therapy on the sensitivity of cardiac beta2
adrenoceptors in patients receiving regular long-acting beta2-agonists. METHODS:
Twelve healthy subjects (6 female), mean age 29 years, were randomised in a
double-blind cross-over study to receive either inhaled placebo or inhaled
budesonide 1.2 mg twice daily, each for 7 days, with a minimum of 7 days washout
period between the two treatments. Patients also received concomitant treatment
with inhaled eformoterol 24 microg twice daily during each of the 2 treatment
periods. The patients attended the laboratory during both treatment periods at
0730 hours, when a dose-response curve for systemic beta2-adrenoceptor responses
to inhaled salbutamol (0.8-3.2 mg) was constructed before and after completing 7
days of each treatment. Early morning (0800 hours) plasma cortisol was also
evaluated as a marker of systemic glucocorticoid activity. RESULTS: There was a
significant fall in 0800 hours plasma cortisol induced by budesonide comparing
pre- and post-values (407 vs 322 nmol.1(-1), but not with placebo. There were no
differences in the response to salbutamol prior to treatment when comparing
eformoterol with placebo versus eformoterol with budesonide. Comparing before and
after within-treatment heart rate response, there was a significant reduction in
peak salbutamol response with eformoterol and placebo, which was partially
reversed by eformoterol and budesonide. For between-treatment comparisons after
eformoterol treatment, the heart rate was significantly higher in the presence of
budesonide in comparison with placebo for peak salbutamol response (change from
baseline), i.e. 24.2 vs 34.7 beats min(-l). There was, however, no significant
difference in the peak delta potassium response to salbutamol after eformoterol
treatment when comparing budesonide with placebo (-0.39 vs -0.48 mmol.1(-1)).
CONCLUSION: Concomitant therapy with inhaled budesonide resensitised the cardiac
beta2-adrenoceptor response to salbutamol in subjects who were receiving regular
twice-daily eformoterol. This may be of clinical relevance in terms of the
propensity for systemic beta2-mediated adverse effects with repeated puffs of
salbutamol, which might conceivably occur in the setting of acute asthma.
PMID- 9754980
TI - The effect of nimesulide versus placebo on hemostasis in healthy volunteers.
AB - OBJECTIVE: The primary objective was to evaluate the effect of 7 days treatment
with nimesulide on bleeding time. Blood coagulation, von Willebrand factor and
platelet aggregation ex vivo were investigated as a secondary objective. METHOD:
A randomised, double-blind, placebo-controlled, parallel group, single centre
study performed on 20 healthy male volunteers who received either placebo or
nimesulide 100 mg twice daily for 7 days. Bleeding time, platelet count and
platelet aggregation, thromboplastin time (prothrombin time), activated partial
thromboplastin time, fibrinogen, Factor VIII:C, vWF:Ag, vWF:RCof and platelet
rich plasma aggregation following stimulation with adenosine 5'-diphosphate,
collagen, arachidonic acid, ristocetin, thrombin and thrombin receptor-activating
peptide were measured at baseline (day 0), and then 3 h after the first (day 1)
and last (day 7) treatment. RESULTS: The bleeding times for all subjects remained
within the normal range throughout the study period, with no significant
differences between the two treatment groups. There were no significant changes
from baseline in platelet aggregation studies or in any of the other haemostasis
tests, with no significant differences between the two groups. No clinically
significant adverse events were reported or observed. CONCLUSIONS: Daily
administration of 200 mg nimesulide for 7 days neither prolongs bleeding time nor
modifies any of the other haemostasis variables measured. The lack of
interactions with important haemostatic mechanisms suggests that nimesulide may
also be used in patients with bleeding problems. This expectation has still to be
confirmed by clinical experience.
PMID- 9754981
TI - Aqueous humour concentration and the intraocular pressure-lowering effect of
topical betaxolol before cataract surgery.
AB - OBJECTIVE: The aim was to study the relationship between aqueous humour betaxolol
concentration and intraocular pressure (IOP). METHODS: In this double-blind,
randomized study, we administered betaxolol (a) or placebo (b) ocularly to 131
patients scheduled for cataract surgery. The patients were randomly divided into
ten groups. In groups 1a and 1b, the drug was scheduled to be instilled 1-2 h, in
groups 2a and 2b 12 h, in groups 3a and 3b 24 h, and in groups 4a and 4b 48 h
before surgery. The pupil was dilated in all eyes prior to surgery. The IOP was
measured with Perkins' applanation tonometer before the instillation of the drug
and just before the peribulbar block. Twenty microlitres of 0.5% betaxolol or
placebo solution was instilled into the eye. IOP was also measured before
instillation of the drug and after 1 2 h in undilated eyes of 20 patients, whose
contralateral eye was to be operated on, to rule out the effect of pupil dilation
on IOP (groups 5a and 5b). Aqueous humour betaxolol concentrations were analysed
using a radioreceptor assay. RESULTS: Betaxolol did not decrease IOP
significantly in eyes with pupillary dilation. Both betaxolol and placebo
decreased IOP significantly in patients without pupillary dilation, the effect of
betaxolol being slightly more pronounced. The betaxolol concentration in aqueous
humour was 731 ng m-1 in group la, 2.4 h after drug instillation. Measurable
concentrations of betaxolol were also detected in aqueous humour in group 4a 47.7
h after drug administration. CONCLUSION: No correlation between aqueous humour
concentration of betaxolol and the effect on IOP was found in eyes where the
pupil was dilated before surgery. A single betaxolol dose did not decrease IOP
significantly in patients undergoing cataract surgery, but the IOP decreasing
effect was, however, clearly seen in patients who did not receive mydriatic
drugs. The routine use of topical betaxolol prior to cataract surgery to decrease
IOP is not recommended.
PMID- 9754982
TI - Ketorolac use in outpatients and gastrointestinal hospitalization: a comparison
with other non-steroidal anti-inflammatory drugs in Italy.
AB - OBJECTIVE: To compare the risk of hospitalization for gastroduodenal ulcer
associated with the use of ketorolac and other non-steroidal anti-inflammatory
drugs (NSAIDs). METHODS: A cohort and a nested case-control study were carried
out. All residents in the region of Umbria (Italy), aged 35-84 years, who had
been given at least one NSAID prescription in 1993 and 1994 were identified.
Exposure to drugs was ascertained through a drug prescription database. We
estimated rate ratios of hospitalization for gastroduodenal ulcer with or without
complications in the current, recent or past period according to exposure to
different NSAIDs. RESULTS: Rate ratio estimates, adjusted for age and sex, were
2.8 for any current NSAID and 1.4 for any recent NSAID. The highest rate ratios
of lesions of any severity for current NSAID use were observed for piroxicam (RR:
4.6) and ketorolac (RR: 3.4). For gastrointestinal haemorrhage or perforation the
highest rate ratios were those for ketorolac (RR: 5.9) and piroxicam (RR: 4.8).
Rate ratio estimates did not change after adjustment for concomitant use of
gastrotoxic drugs, use of gastroprotective agents not associated with NSAIDs and
prior use of NSAIDs. CONCLUSION: Our study demonstrates the need to adhere to the
restrictions relating to the indications and duration of use of ketorolac. At
present piroxicam represents a greater public health concern since it is
confirmed to be among the most gastrotoxic NSAIDs and is one of the most commonly
prescribed NSAIDs in Italy.
PMID- 9754983
TI - Lack of drug-drug interaction between three different non-steroidal anti
inflammatory drugs and omeprazole.
AB - OBJECTIVE: To study, in three separate investigations, the potential interaction
between omeprazole and three different non-steroidal anti-inflammatory drugs
(NSAIDs; diclofenac, naproxen and piroxicam) in healthy male and female subjects.
METHODS: Each investigation was an open, randomized, three-way cross-over study,
in which the subjects were given omeprazole 20 mg once daily for 1 week, the
NSAID in therapeutic daily doses (diclofenac 50 mg bid, naproxen 250 mg bid, or
piroxicam 10 mg om), or a combination of omeprazole and each NSAID. The plasma
concentrations of the NSAID as well as of omeprazole were determined on the last
day of each investigation period. RESULTS: None of the NSAIDs studied had any
effect on the plasma concentration versus time curve (AUC) of omeprazole. It was
also demonstrated that omeprazole 20 mg daily had no significant influence on the
pharmacokinetics of the NSAIDs. The AUC ratio, (NSAID +omeprazole):NSAID alone,
was 1.11, 0.99, and 0.99 for diclofenac, naproxen, and piroxicam, respectively.
CONCLUSION: Diclofenac, naproxen, and piroxicam can be administered together with
omeprazole 20 mg daily without need for dosage alteration. There was no
significant change in the bioavailability of theses NSAIDs during omeprazole
therapy in this study.
PMID- 9754984
TI - Safety and pharmacokinetics of a single oral dose of amisulpride in healthy
elderly volunteers.
AB - OBJECTIVE: Amisulpride is a substituted benzamide neuroleptic, which binds
selectively to dopamine D2 and D3 receptors, mainly in the limbic structures.
States of delusion and agitation occur frequently in the population aged more
than 65 years, especially in demented patients and this sometimes requires the
use of neuroleptics. The objectives of this study were to determine the safety
and the pharmacokinetic profile of 50 mg of amisulpride administered orally as a
single dose to elderly volunteers. METHODS: Twenty healthy volunteers (10 men and
10 women) aged 65 79 years were included in this open trial. Frequent
measurements of blood pressure and heart rate were made and ECG and blood samples
were performed up to 72 h after drug intake. RESULTS: The overall clinical and
cardiovascular safety was satisfactory. The mean Cmax of the racemate amisulpride
in elderly people was 64.1+/-6.7 ng ml(-1), and was not different from the value
of 56+/-4.1 ng ml(-1) in young subjects. As with the Cmax, the mean values of
t1/2 and AUC in elderly people (15.6+/-1.3 h and 667+/-51 ng. ml(-1).h,
respectively) were not different to values observed in young subject
(respectively 11.7+/-0.5 h and 603+/-25 ng m1(-1) h). CONCLUSION: A single oral
dose of amisulpride was well tolerated and showed a similar pharmacokinetic
profile in healthy elderly and young subjects. However, these findings should be
confirmed after multiple dosing in a larger population in order to establish the
lack of need of dosage adjustment in this elderly population.
PMID- 9754985
TI - Comparative pharmacokinetic study of oral and rectal formulations of artesunic
acid in healthy volunteers.
AB - OBJECTIVE: A single cross-over, comparative pharmacokinetic study of oral and
rectal formulations of 200 mg artesunic acid in 12 healthy Malaysian volunteers
is reported. METHODS: Plasma concentrations of artesunic acid and
dihydroartemisinin were determined simultaneously by HPLC with electrochemical
detection. The test drug was well tolerated and no undesirable adverse effects
were observed. RESULTS: Comparison of pharmacokinetic parameters of artesunic
acid after oral and rectal administration showed statistically significant
differences in t(max) and AUC, with no changes for Cmax and t1/2. As for
dihydroartemisinin, differences were observed for t(max) and Cmax but not for
AUC. CONCLUSION: There appear to be pharmacokinetic differences between oral and
rectal modes of administration. The significance of these findings should be
explored in malaria patients before appropriate therapeutic regimens are devised.
PMID- 9754986
TI - Pharmacokinetics of nimustine, methotrexate, and cytosine arabinoside during
cerebrospinal fluid perfusion chemotherapy in patients with disseminated brain
tumors.
AB - OBJECTIVE: This study was conducted to evaluate the pharmacokinetics of
anticancer drugs in cerebrospinal fluid (CSF) perfusion chemotherapy. METHODS: We
administered CSF perfusion chemotherapy with nimustine (ACNU), methotrexate
(MTX), and cytosine arabinoside (Ara-C) to three patients with disseminated
malignant brain disease. The drugs were infused via Ommaya's reservoirs to the
lateral ventricle and removed by drainage from the temporal lobe or lumbar spine.
CSF and plasma concentrations of the anticancer drugs were determined by high
performance liquid chromatography and fluorescence polarization immunoassay.
RESULTS: The concentrations of anticancer drugs in the discharged CSF peaked
about 40 min after the start of a 1-h CSF perfusion. After the perfusion, the
drug level in CSF decreased exponentially in a monophasic manner. ACNU and Ara-C
were not detectable in the discharged CSF in the temporal lobe at 6 h and 48 h
after perfusion, respectively, but MTX was detectable at 48 h. The maximum
concentration ratio of anticancer drugs and the duration of perfusion were
inversely correlated. The plasma concentrations of anticancer drugs were much
lower than those in CSF. The half-life of ACNU was very short (0.2-1.1 h),
whereas the half-lives of MTX and Ara-C were relatively long (2.81-13.5 h and
1.84 6.25 h, respectively). The half-lives of the anticancer drugs in CSF tended
to decrease with repeated CSF perfusion chemotherapy. CONCLUSION: Results suggest
that CSF perfusion chemotherapy enables a high concentration of anticancer drug
to be administered for dissemination in the spinal cord within a short period of
time, with minimal adverse effects.
PMID- 9754987
TI - Zolpidem 10 mg given at daytime is not antagonized by 300 mg caffeine in man.
AB - OBJECTIVE: Caffeine counteracts various effects of traditional benzodiazepines
(BZDs). As zolpidem, a short-acting hypnotic, is an atypical GABAA-BZD agonist,
we investigated when caffeine would counteract the effects of zolpidem as well.
METHODS: In daytime study I, zolpidem 10 mg (capsule) and caffeine 150 or 300 mg
(in decaffeinated coffee) were given, alone and in combinations, to parallel
groups (n = 15-17) of healthy students in double-blind and placebo-controlled
manner. Objective and subjective tests were done before and 45 min and 90 min
after intake. Ranked delta values (changes from baseline) were analysed by one
way contrast ANOVA and Scheffe's tests. In daytime study II, four healthy
subjects took zolpidem 10 mg alone, and together with blinded caffeine 250 mg or
(at -45 min) erythromycin 750 mg. Objective and subjective effects were measured
and plasma zolpidem concentrations assayed at baseline and 45 min and 90 min
after zolpidem intake. RESULTS: In study I, practice effects after placebo (ad +
30%) were seen for letter cancellation and digit symbol substitution but not for
flicker fusion tests. Zolpidem alone significantly impaired (P < 0.05 vs delta
placebo) letter cancellation and digit symbol substitution at 45 min and 90 min,
lowered the flicker fusion threshold at 45 min, and caused subjective drowsiness,
mental slowness, clumsiness and feeling of poor performance. Caffeine alone
showed a non-significant trend to improve objective performance. The combined
effects of zolpidem and either dose of caffeine matched those measured after
zolpidem alone. Zolpidem + caffeine 300 mg was not stronger than zolpidem +
caffeine 150 mg in impairing immediate memory and causing subjective sedation. In
study II, zolpidem caused objective and subjective sedation; neither caffeine nor
erythromycin modulated the effects of zolpidem or plasma zolpidem concentrations.
CONCLUSION: The sedative effects of 10 mg of zolpidem are not antagonized by 150
300 mg of caffeine in pharmacodynamic or pharmacokinetic terms.
PMID- 9754988
TI - Genotypes for the cytochrome P450 enzymes CYP2D6 and CYP2C19 in human longevitY.
Role of CYP2D6 and CYP2C19 in longevity.
AB - OBJECTIVE: To test whether some genotypes for CYP2D6 or CYP2C19 could contribute
to longevity, we genotyped 241 Danish nonagenarians and centenarians for CYP2D6
and CYP2C19. METHODS: For CYP2D6 we identified the alleles CYP2D6*1, CYP2D6*3 and
CYP2D6*4 with allele-specific polymerase chain reaction (PCR). The CYP2D6*5
alleles were identified with a long PCR method. For CYP2C19 we identified the
alleles CYP2C19*1, CYP2C19*2 and CYP2C19*3 with an oligonucleotide ligation
assay. RESULTS: The four alleles for CYP2D6 did not occur in Hardy-Weinberg
proportions. The frequency of poor metabolism was slightly higher (10.2%) than
expected [7.7%; odds ratio (OR) = 1.36 (0.75-2.40)]. The genotypes for CYP2C19
occur in Hardy-Weinberg proportions. The frequency of poor metabolism (3.8%) was
not significantly different from a young control group [3.1%; OR = 1.21 (0.26
5.75)]. CONCLUSION: CYP2D6 could play a role in human longevity due to the lack
of Hardy-Weinberg proportions. If CYP2D6 only plays a role in longevity by
protecting the poor metabolizers from cancer, we should expect a rise in the
frequency in these genotypes in Denmark from 7.7% among young adults to 10-11%
among very old people. We found a frequency of poor metabolism of 10.2% in the
very old group. CYP2C19 is - due to the occurrence of Hardy-Weinberg proportions
and the expected number of poor metabolizers unlikely to contribute to human
longevity.
PMID- 9754989
TI - Genetic polymorphism of debrisoquine (CYP2D6) and proguanil (CYP2C19) in South
Pacific Polynesian populations.
AB - OBJECTIVE: Genetic oxidation polymorphisms of debrisoquine (CYP2D6) and proguanil
(CYP2C19) were studied in unrelated healthy South Pacific Polynesian volunteers
recruited in the South Island of New Zealand. METHODS: Phenotyping for CYP2D6 and
CYP2C19 activities was determined using debrisoquine and proguanil, respectively,
as probe drugs by measuring the urinary metabolic ratio of parent drug and its
metabolite. RESULTS: Of 100 Polynesian subjects phenotyped, the metabolic ratio
of debrisoquine ranged from 0.01 to 9.94. Therefore, all South Pacific
Polynesians were classified as extensive metabolizers of debrisoquine according
to previously established criteria of the antimode. The prevalence of poor
metabolizers of debrisoquine (CYP2D6) in this Polynesian population is 0% (95%
confidence interval of 0-3.6%). Oxidation polymorphism of CYP2C19 using proguanil
as a probe was also studied in 59 Polynesian volunteers. The frequency
distribution of the proguanil/cycloguanil ratio was bimodal. The
proguanil/cycloguanil ratios for these subjects ranged from 0.09 to 34.4. Using a
recommended proguanil/cycloguanil ratio cut-off point of 10 established in
Caucasian populations, eight Polynesian subjects were identified as poor
metabolizers of proguanil (CYP2C19), which corresponds to a poor metabolizer
phenotype frequency of 13.6% (a 95% confidence interval of 5.9-24.6%).
CONCLUSION: The incidence of poor metabolizer phenotypes for debrisoquine
(CYP2D6) in South Pacific Polynesians appears to lower than in Caucasian
populations, while the prevalence of poor metabolizers for proguanil (CYP2C19) in
this ethnic population is higher. The frequencies of the poor metabolizer
phenotype for debrisoquine and also for proguanil in South Pacific Polynesians
are similar to those reported in Asian populations.
PMID- 9754990
TI - Variability of coumarin 7- and 3-hydroxylation in a Jordanian population is
suggestive of a functional polymorphism in cytochrome P450 CYP2A6.
AB - OBJECTIVE: To determine the variability of coumarin 7- and 3-hydroxylation in a
human population and to evaluate the evidence for the existence of genetic
polymorphism in these pathways. 7-Hydroxylation of coumarin is considered to be a
detoxication pathway, whilst 3-hydroxylation, which predominates in rats, leads
to hepatotoxicity in the rat. Coumarin metabolic phenotypes could aid in refining
the risk evaluation for humans of dietary and environmental exposure to coumarin
and for the chronic use of coumarin in high doses as a drug to treat lymphoedema
and certain cancers. METHODS: Healthy male and female Jordanian volunteers (n =
103) were administered 2 mg coumarin by mouth and collected their 0-8-h urines.
These, together with pre-dose blank urines, were analysed by selected-ion
monitoring gas chromatography mass spectrometry for their content of the coumarin
metabolites 7-hydroxycoumarin (70HC) and 2-hydroxyphenylacetic acid (2OHPAA), the
latter arising from the 3-hydroxylation pathway. RESULTS: After coumarin
administration, excretion of both 70HC and 2OHPAA was highly variable. A coumarin
metabolic ratio (2OHPAA/7OHC) was suggestive of polymorphism. At least one
subject had a metabolic response similar to an individual known to be both
phenotypically and genotypically (CYP2A6 gene) 7-hydroxylation-deficient.
CONCLUSION: In the light of the finding of high variability and possible
polymorphism in both the 7- and 3-hydroxylation of coumarin in a human
population. we recommend a reappraisal of the risk evaluation of human exposure
to coumarin, particularly in pharmaceutical doses.
PMID- 9754991
TI - Pharmacokinetics and pharmacodynamics after oral and intravenous administration
of tolcapone, a novel adjunct to Parkinson's disease therapy.
AB - OBJECTIVE: To evaluate fully the pharmacokinetics and pharmacodynamics of
tolcapone, a novel inhibitor of catechol-O-methyltransferase (COMT), after oral
and intravenous administration. METHODS: Sixteen healthy male volunteers were
given tolcapone in single doses of 200 mg orally and 50 mg intravenously,
separated by a washout period of 7 days or more, in a single-center, open-label,
randomized, cross-over study. Pharmacokinetic parameters were calculated using
both compartmental and non-compartmental methods; pharmacodynamics were evaluated
from erythrocyte COMT activity. RESULTS: After an initial lag time of 0.5 h,
tolcapone was rapidly absorbed (peak plasma concentrations were reached within
approximately 2 h) following either zero- or first-order absorption kinetics. The
absolute bioavailability of an oral dose was approximately 60%. The volume of
distribution was approximately 9 1, and the total clearance was approximately
71.h-l, resulting in a mean plasma half-life of 1.8 h. The degree of erythrocyte
COMT inhibition was closely related to tolcapone plasma concentration; a rebound
in COMT activity was observed after tolcapone withdrawal. Both oral and
intravenous tolcapone were well tolerated. DISCUSSION: Because of its relatively
low systemic clearance, tolcapone exhibits only a small degree of first-pass
metabolism and a relatively good oral bioavailability, which explains the higher
plasma concentrations and stronger COMT inhibition observed with tolcapone
compared with entacapone, another COMT inhibitor. The pharmacokinetic and
pharmacodynamic profile of tolcapone obtained in this study underlines the
potential of the agent to be used as an adjunct to levodopa in the treatment of
Parkinson's disease.
PMID- 9754992
TI - Chronic hypercapnia should not exclude patients from lung volume reduction
surgery.
AB - OBJECTIVE: Chronic hypercapnia is still considered to increase the risk for
perioperative mortality and therefore to be a contraindication for lung volume
reduction surgery (LVRS). The aim of this study was to analyse the influences of
hypercapnia upon postoperative outcome. METHODS: The functional improvement
(preop vs. 3 months postop) and clinical outcome was studied in 22 patients with
chronic hypercapnia (preoperative arterial pCO2 > or = 45 mmHg) who underwent
LVRS between 9/94 and 2/97 and were compared to all other patients (n = 58)
without hypercapnia. Data are expressed as the mean +/- SEM. RESULTS: The 30-day
mortality was 9.1% (2/22) in patients with chronic hypercapnia (HC) and 5.2%
(3/58) in patients with normal arterial pCO2 levels (control) (P = n.s). The stay
on the ICU (3.5 +/- 0.8 vs. 2.1 +/- 0.3 days) and duration of chest drainage (7.3
+/- 1.2 vs. 7.2 +/- 0.8 days) was similar between both groups (HC vs. control) (P
= n.s). The preoperative lung function (% of predicted) and blood gas (mmHg)
parameters were significantly worse in HC patients compared to control patients.
In both groups significant functional improvements were observed: FeV1 in the
control group increased by 37% within the first 3 months (29.1 +/- 1.7% of
predicted vs. 39.9 +/- 3.1% of predicted, P = 0.0198). In the HC group, FeV1
increased by 73% which was even higher than in the controls (19.5 +/- 1.5% of
predicted vs. 33.7 +/- 4.7% of predicted, P = 0.0385). All patients of both
groups who died perioperatively had a significantly higher severity of
parenchymal destruction than those who survived (P = 0.0277 and 0.0380,
respectively). CONCLUSIONS: Patients with chronic hypercapnia alone, had no
significantly higher mortality and morbidity, and therefore should not be
excluded from LVRS. However, the presence of additional risk factors, such as
homogeneity of disease, high degree of parenchymal destruction or pulmonary
hypertension should be considered as contraindications for the procedure.
PMID- 9754993
TI - Video-assisted thoracoscopic surgery: experience with 341 cases.
AB - OBJECTIVE: Until recently, thoracoscopy had been used primarily for diagnostic
purposes for more than 80 years in thoracic diseases. In this report we reviewed
our video-assisted thoracoscopic surgery experience with 341 cases focusing on
indications, operative procedures, complications or failure rates. PATIENTS AND
METHODS: Over the last 3 years, we performed 459 video-assisted thoracoscopic
procedures. There were 206 male and 135 female patients. RESULTS: The indications
were diagnostic in 171 cases, and therapeutic in 170 cases. There were no
operative mortality. Non-fatal complications were seen in 15 cases (4.4%). The
mean postoperative stay was 5 days. The specific procedures performed were
operations on the pleura (237 cases), lung (158 cases), mediastinum (56 cases)
and pericardium (four cases). Conversion to thoracotomy was needed in 43 cases
(12.6%). Definitive diagnosis was obtained in 100% of patients with pulmonary
nodule/mass or diffuse lung disease, and 95.2% of patients with undiagnosed
pleural effusions. The success rate of thoracoscopic approach in non-tuberculous
thoracic empyema was 87.3%. CONCLUSIONS: Video-assisted thoracoscopic surgery is
an ideal procedure in the following situations: (1) undiagnosed pleural effusion,
(2) recurrent pneumothorax or bullous lung disease, (3) stage II thoracic
empyema, (4) lung cancer staging, (5) peripheral pulmonary nodule, and (6) wedge
biopsy for diffuse lung disease.
PMID- 9754994
TI - Is aggressive surgery in pleural empyema justified?
AB - OBJECTIVE: High risk and a long hospitalization time are often quoted as negative
aspects of aggressive surgery in pleural empyema. We did a retrospective analysis
evaluating outcome and duration of hospitalization in patients treated according
to an aggressive schedule. METHODS: Since 1989 we have treated 101 patients with
pleural empyema (72 males, 29 females; mean age 50.3 years, range 11-91 years; 77
metapneumonic empyema, 24 empyema following trauma or abdominal surgery). Sixty
nine patients had had unsuccessful conservative pre-treatment (antibiotics,
thorcozentses, drainage/irrigation, VATS). Thirty-one were critically ill
patients. In eight cases a seropurulent stage of empyema was present, 17 patients
had fibrinous membranes, 30 an organizing stage with and 46 without well
identifiable dissection plane. Eighty-five patients proceeded to thoracotomy.
Pulmonary abscesses or indurative pneumonia necessitated wedge-resection,
lobectomy, or pneumonectomy in 29 cases. In the presence of gross necroses or
callosities not amenable to decortication primary open-window thoracostomy (n =
22) was carried out. In six cases a secondary open-window thoracostomy was
carried out because of persisting putrid secretion and sepsis persisting after
decortication or after drainage. The thoracostomy was closed when clean
granulative tissue developed. Sixteen patients underwent only drainage and
irrigation because of an early stage or because of a general condition not
permitting thoracotomy. RESULTS: Three patients died due to severe sepsis not
responding to treatment, one had fatal bleeding from a duodenal ulcer (mortality
rate 3.9%). The others were able to resume their preoperative activities. The
median duration of hospitalization was 14 days (mean 21.1 days; SEM 1.7 days).
CONCLUSION: Aggressive surgery for pleural empyema beyond the seropurulent stage
ensures rapid relief from sepsis at a low mortality rate even in very ill
patients.
PMID- 9754995
TI - Posptneumonectomy empyema.
AB - OBJECTIVE: Postpneumonectomy empyema can be managed in many different ways, with
variable results. In the presence of bronchopleural fistula treatment is much
more complicated. The results of therapy of postpneumonectomy empyema managed by
thoracomyoplasty and closure of the bronchial fistula by pedicled muscle flap are
presented. METHODS: Seven hundred and seventy-eight pneumonectomies had been
performed for bronchogenic carcinoma. Empyema occurred in 35 (4.5%) cases. There
were 22 (62.8%) patients with associated bronchopleural fistula. Depending on
their management, patients were divided into two groups: I: 15 patients managed
with tube and/or open-window thoracostomy only, II: 20 patients who were treated
with thoracomyoplasty, which meant the excision of the fibrotic thoracic wall,
combined with the transposition of the pedicled muscle flap into the empyema.
There was a need to resect three to four ribs. Eight patients had large
bronchopleural fistulas. Before thoracomyoplasty was conducted, tube drainage
ranged from 16 to 120 days (average 46.6 days), the open-window thoracostomy
ranged from 27 days to 13 years (average 574 days). RESULTS: Only one patient
from group I was cured, there were five (33.3%) deaths. Nineteen (95.0%) patients
from group II were successfully cured. Eight large bronchial fistulas were closed
by suturing the muscle flap into the fistula lumen. The length of hospitalisation
ranged from 9 to 30 days (median 17.6). The mortality rate in this group was 0%.
CONCLUSIONS: The excision of the thoracic wall combined with the transposition of
the pedicled muscle flap is safe and effective in the management of
postpneumonectomy empyema. Bronchopleural fistulae can be definitely closed by
suturing the pedicled muscle flap into fistular lumen.
PMID- 9754996
TI - Pulmonary sequestration: a review of 26 cases.
AB - OBJECTIVES: Pulmonary sequestration is a continuum of lung anomalies for which no
single embryonic hypothesis is yet available. The aim of this study was to assess
the diagnostic tools and treatment for the rare condition, pulmonary
sequestration, in an unspecialised centre. METHODS: We performed an analysis of
26 cases of pulmonary sequestration (paediatric and adult) operated at the Centre
Hospitalier Universitaire Vaudois between May 1959 and May 1997. A review of the
extralobar and intralobar types of sequestrations is discussed. Angiography is
compared to other diagnostic tools in this condition, and treatment is discussed.
RESULTS: Twenty-six cases of pulmonary sequestrations, a rare congenital
pulmonary malformation, were operated on in the defined time period. Seventy
three percent (19) of the cases were intralobar and 27% (seven) extralobar.
Extralobar localisation was basal in 71% and situated between the upper and the
lower lobe in 29%. In six cases, the diagnosis was made by exploratory
thoracotomy. In the other 20 cases, diagnosis was evoked on chest X-ray and
confirmed by angiography. Lobectomy (46%) was the most common treatment
procedure. Segmental resection was performed in 30% of the cases and bilobectomy
in 4%. Post-operative morbidity was low. The most significant complications were
pleural empyema, haemothorax and haemopneumoperitoneum in case of extralobar
sequestration. There was no evidence of metaplasia or pre-neoplastic changes.
CONCLUSIONS: Despite its rarity, some radiological features are sufficiently
suggestive of diagnosis of pulmonary sequestration. Investigations are necessary
in order to avoid unexpected pathology at the time of operation. Resection of the
involved lung leads to excellent results and the long-term outcome is highly
favourable.
PMID- 9754997
TI - Surgical treatment of echinococcosis by a transthoracic approach: a review of 85
cases.
AB - OBJECTIVE: Human echinococcosis remains a serious health problem for the
Mediterranean countries, among them Greece. As there is no effective medical
therapy, surgery is still the treatment of choice. MATERIAL AND METHODS: We
present our experience in the surgical management of hydatidosis by a
transthoracic approach, based on 85 patients (49 male, 36 female, aged 4-86
years) treated during 1986-1996. RESULTS: Twenty-one patients (26.3%) appeared
with complications as: hydatidemesis (n = 5), hydropneumothorax (n = 3), cyst
infection (n = 3), empyema thoracis (n = 8), cholebronchial (n = 3) and
cholebronchopleural fistula (n = 1). The location of the cysts was: 61 in the
lungs (right, 29; left, 24; bilateral, eight), 31 on the liver dome, six in the
pleural cavity, two in the mediastinum, and one in each of pericardium, chest
wall, and right pararenal space. Surgical approach involved a thoracotomy or
median sternotomy in all cases. Pulmonary endocystectomy and capitonnage was the
procedure of choice in the surgical management. Hepatic cysts were approached
through a right thoracophrenotomy and were managed with evacuation of the main
and daughter cysts, suture of the diaphragm to the margins of the cyst, and
drainage of the cystic and pleural cavities. There was no in-hospital mortality.
Major postoperative complications were: empyema thoracis (n = 3), biliary fistula
(n = 2), and bronchopleural fistula (n = 1). Five patients presented later with
seven recurrences of the disease. CONCLUSION: Transthoracic approach is a good
and safe choice in surgical treatment of both the intrathoracic and the
(concomitant or not) hydatid cysts on the upper surface of the liver.
PMID- 9754998
TI - Clinical experiences with minimally invasive mitral valve surgery using a
simplified Port Access technique.
AB - OBJECTIVE: Using the initial experiences with the Port-Access technique for the
treatment of mitral valve disease some changes were made thus resulting in more
simple and faster procedures. METHODS: Twenty-nine patients (13 male, 16 female,
aged 30 to 75 years, median 62.5 +/- 11.0 years) underwent minimally invasive
mitral valve surgery between May 1996 and December 1997. The underlying diseases
were: mitral valve insufficiency (n = 16), mitral valve stenosis (n = 7) and
combined mitral valve disease (n = 6). Through a small right thoracotomy (5-7 cm)
access to the pericardium and the heart was gained. Cardiopulmonary bypass was
instituted through femoral cannulation and an intraaortic balloon-catheter was
introduced for aortic occlusion, aortic root venting and delivery of cold
crystalloid cardioplegia. Mitral valve repair (five patients) or replacement (24
patients) was performed. RESULTS: There was no death during the whole follow-up
period. There was no perivalvular leak and only minor residual mitral valve
regurgitation was observed on intraoperative or postoperative (3 months)
transesophageal echocardiography in three patients. There was no postoperative
study-related complication. Time of ventilation and intensive care unit were
comparable with the data of patients undergoing conventional mitral valve surgery
but hospital stay was shorter in the last 10 consecutive cases. CONCLUSIONS: This
simplified technique of mitral valve surgery combines the advantage of less
invasive operative and good cosmetic results with the safety of conventional
mitral valve surgery. At our institution this technique presents in well selected
patients suffering from mitral valve disease the procedure of choice.
PMID- 9754999
TI - Aortic valve reconstruction associated to ascending aorta tubular graft
replacement in aortic incompetence by annuloaortic ectasia.
AB - OBJECTIVE: Aortic valve incompetence associated with severe aortic ectasia is
usually treated by aortic valve and ascending aorta replacement. In cases of
isolated aortic ectasia or in Type A aortic dissection the valve is often normal
and the incompetence is just due to annular dilatation. Such conditions lead to
the application of various valve-sparing surgical techniques, as described by
Senning et al., showing the advantages of preservation of the native valve, but
the disadvantage of a high technical complexity and a high incidence of
recidivation. METHODS: We describe a valve-sparing surgical procedure, which has
the advantage of a direct and simple approach together with satisfying mid-term
results. After the aortic bulb has been fully transected, the excessive wall
tissue is resected by two or three triangular excisions just above the valve
commissures. Wall excision was indicated in those patients with an aortic
diameter exceeding 65 mm at the sino-tubular junction. Tissue excision should not
exert tension on to the coronary ostia or excessively reduce aortic diameter.
Three external Teflon strips, overriding each other, are placed around the aortic
bulb and are included in the direct suture of the edges of the triangular
excisions. They are fixed by a running suture over the free border of the bulb.
Aortic valve commissures are resuspended when needed. In this way, the aortic
bulb, with a competent valve, is wrapped in a prosthetic and inextensible graft.
The aortic continuity is then re-established with the interposition of a tubular
dacron graft. RESULTS: From April 1990 to December 1995, 21 patients (mean age 48
years, range 32-70) scheduled for surgery for aortic valve incompetence
associated with annuloaortic ectasia were treated with this technique. In one
patient the procedure failed to achieve a satisfying valve competence and the
valve was replaced. In another case a prolapse of the non-coronary cusp required
reoperation with aortic valve replacement, without further complications. At
follow-up time (mean 42 months, range 18-78), all patients were well and healthy,
with control echoes showing no residual valve incompetence and with invariate
bulb diameters at every successive examination. CONCLUSIONS: Our experience shows
that this new valve-sparing approach allows safe and persistent correction of
aortic valve incompetence and annuloaortic ectasia although longer term follow up
is needed.
PMID- 9755000
TI - Long-term survivors with pN2 non-small cell lung cancer after a complete
resection with a systematic mediastinal node dissection.
AB - OBJECTIVE: A substantial number of surgical patients with pN2 disease have
survived longer than 5 years without any evidence of recurrence, although the
surgical indications for those patients remain controversial. The present study
was performed in order to clarify the clinical characteristics of the long-term
survivors with pN2 disease. METHODS: We retrospectively reviewed the cases of 111
patients with pN2 disease who had undergone a complete resection with a
systematic mediastinal lymph node dissection from 1974 through 1991. RESULTS: Of
the 111 patients with pN2 disease, 20 survived longer than 5 years after a
surgical resection. When both the pre- and post-operative conditions were
compared between the long-term survivors and the others, the long-term survivors
were characterized by significantly higher proportions of cN0 disease (P =
0.031), pT1 disease (P = 0.004), skip metastasis without hilar node metastasis (P
= 0.028), and metastasis of a single mediastinal station (0.044). Of those
characteristics, only the likelihood of having cN0 disease could be pre
operatively determined. The survival rate of such a population with cN0-pN2
disease was 34.5% at 5 years and 29.6% at 10 years after a complete resection,
respectively. CONCLUSIONS: Pathologic N2 patients with some favorable prognostic
factors can survive long-term after a complete resection combined with a
systematic mediastinal lymph node dissection. At present, due to the lack of any
effective adjuvant therapy, a systematic mediastinal node dissection should be
routinely performed even in patients with cN0 disease.
PMID- 9755001
TI - Thirty-day mortality and long-term survival following surgery for prosthetic
endocarditis: a study from the UK heart valve registry.
AB - OBJECTIVE: To assess the 30-day mortality, long-term survival and freedom from
reoperation following surgery for prosthetic endocarditis (PVE). METHOD: A
retrospective analysis of data from the UK Heart Valve Registry of 322 patients
who had undergone single mechanical/bioprosthetic valve replacement for PVE
between 1 January 1986 and 31 December 1996. The mean age was 54.9 +/- 12.8 years
and 213 (66.1%) were males. There were 170 aortic and 152 mitral valve
implantations. Eighty-five (26%) of the infected valves were bioprosthetic and
237 (74%) were mechanical. Of the new prostheses implanted 53 (17%) were
bioprosthetic and 269 (83%) were mechanical. Of those with infected
bioprostheses, 50 (15.2%) had mechanical valves at redo surgery, whilst 219
(68.3%) of infected mechanical prostheses were re-replaced by mechanical
prostheses. The follow-up was 98% complete with a total of 1084.9 patient years.
RESULTS: The 30-day mortality was 63 (19.9%; 95%CI 15.9-24.7%). There were 85
late deaths. One, 5 and 10 year survival rates were 67.1% (61.6-72.0%), 55.0%
(49.0-60.7%) and 37.6% (27.9-47.2%), respectively. Age was the only significant
determinant of 30-day mortality (P = 0.04). Age (P = 0.001) and explanting of
infected bioprosthesis and replacement by mechanical valve (P = 0.04) determined
long-term survival (P = 0.001). The incidence of re-reoperation was 9.9%. Freedom
from reoperation for PVE was 88.4, 87.3 and 87.3% at 1, 5 and 10 years,
respectively. Explanting of bioprosthesis and replacement by mechanical valve (P
< 0.001) and reoperation within 60 days of native valve replacement (P = 0.02)
were determinants of reoperation for PVE. Freedom from death or reoperation was
61.1, 50.6 and 34.2% at 1, 5 and 10 years, respectively. Age (P = 0.003),
explanting of bioprosthesis and replacement by mechanical valve (P = 0.002) and
the period between prosthetic re-replacement (P = 0.04) determined freedom from
death or reoperation. CONCLUSION: Operation for PVE carries a high 30-day
mortality and reduced long-term survival. There is no evidence that type of
prosthesis used for re-reoperation determines survival or freedom from re
reoperation.
PMID- 9755002
TI - Cardiac surgery with extracorporeal circulation in 23 infants weighing 2500 g or
less: short and intermediate term outcome.
AB - OBJECTIVE AND METHODS: From September 1990 to February 1997, 23 consecutive
critically ill infants (12 males, 11 females) weighing 2500 g or less underwent
cardiac surgery necessitating extracorporeal circulation (ECC). A retrospective
study was carried out to evaluate short- and intermediate-term outcome. Mean
weight at operation was 2265 g (range 1750-2500 g). Mean age at operation was 24
days. The indications for surgery were transposition of the great arteries (TGA;
7), ventricular septal defect (VSD; 4), aortic stenosis (AS; 3), univentricular
heart (UVH; 2), tetralogy of Fallot (TOF; 2), interrupted aortic arch (IAA; 2),
atrial septal defect (ASD; 1), atrioventicular septal defect (AVSD; 1) and total
abnormal pulmonary venous return (TAPVR; 1). All patients were in NYHA class IV;
17 patients (74%) were intubated pre-operatively. RESULTS: The mean aortic cross
clamping time was 40 min. Twelve patients required deep hypothermia (<20 degrees
C) with total circulatory arrest (mean duration 19 min). All patients were
successfully weaned from extracorporeal circulation (ECC). Five patients left the
operating room with an open sternum (mean duration before closure: 3.5 days).
Mean duration of artificial ventilation was 10.6 days; of inotropic support 6.7
days and of intensive care stay 17.8 days. Severe complications were observed in
19 patients (83%): cardiac failure requiring high inotropic support (13), sepsis
(7), and acute renal insufficiency (5). One patient needed a ventricular assist
device. Five patients (22%) died in the intensive care unit (ICU): 2 AS with
fibroelastosis, 2 IAA with VSD. and 1 UVH with pulmonary atresia. At discharge
from the ICU, 7 patients were receiving no treatment. Mean duration of follow-up
was 32 months (range 2-80 months). We had 2 reoperations: 1 for right ventricular
outflow tract obstruction 1 year after a switch operation and 1 for mitral valve
replacement 1 year after total abnormal pulmonary venous return repair (death 30
days post mitral valve replacement). Survival at I year was 73%. At the last
clinical examination 16 patients were in NYHA class I. CONCLUSION: Despite the
severity of pre-operative cardiac disease, early surgical repair with ECC in
infants weighing 2500 g or less is feasible with tolerable mortality yet with
significant early morbidity.
PMID- 9755003
TI - Ventriculo-arterial discordance: switching the morphologically left ventricle
into the systemic circulation after 3 months of age.
AB - OBJECTIVE: To retrospectively examine a 4 year policy of restoring the
morphologically left ventricle to the systemic circuit in patients presenting
after 3 months of age with ventriculo-arterial discordance with or without
associated atrio-ventricular discordance. This policy was stimulated by the known
tendency of the morphologically right ventricle to develop dysfunction sooner or
later when left in the systemic circuit. Such a policy dictates a more complex
surgical approach and, at this point, it remains controversial whether or not the
increased surgical complexity is warranted. METHODS: From July 1, 1993 to March
31, 1997, a total of 29 patients were entered into a protocol for placement of
the morphologically left ventricle into the systemic circuit. Three groups of
patients were identified. Group I; congenitally corrected transposition in 14
patients -- were treated with either a Senning plus arterial switch operation or
Senning plus Rastelli procedure. Group II; failed atrial switch procedure in 12
patients of which nine proceeded to arterial switch operation with Senning or
Mustard takedown and atrial reseptation. Group III; D-transposition of the great
vessels presenting more than 1 year after birth in three patients who underwent
arterial switch operation alone. A deconditioned morphologically left ventricle
required reconditioning by means of preparatory pulmonary artery banding in 17 of
29 patients. In the patients requiring pulmonary artery banding, an average of
2.1 pulmonary artery bandings was required to prepare the morphologically left
ventricle for a systemic pressure workload. RESULTS: In those patients with a
deconditioned morphologically left ventricle requiring preparatory pulmonary
artery banding, the mean ratio between the left ventricular and right ventricular
systolic pressure increased from 0.48 to 0.95. The left ventricular mass
increased from 46.6 to 81.8 g/m2 in five patients subjected to serial MRI
measurement. Three patients failed the preparatory pulmonary artery banding and
did not proceed to anatomical correction. Two subsequently died at a later time.
In the patients proceeding to complete anatomical correction: group I -- there
were no early or late deaths. Two patients required pacemaker implantation post
operatively. Group II -- there were two in-hospital deaths, one early due to
intrapulmonary hemorrhage and one late, secondary to postoperative left
ventricular failure with a stormy post-operative course requiring successful ECMO
placement and weaning. These patients were 18 and 25 years old, respectively. One
patient proceeded to cardiac transplantation 3 months after surgery due to
ongoing morphologically left and right ventricular dysfunction. Group III -- all
patients continue to do well. CONCLUSIONS: Late anatomic correction of ventriculo
arterial discordance with or without atrio-ventricular discordance can be
performed at a relatively low risk. Reconditioning of the morphologically left
ventricle can be achieved by sequential pulmonary banding but is not without
risk. Failure to achieve adequate reconditioning of the morphologically left
ventricle by pulmonary artery banding in the older patient probably increases the
risk of non-survival and may be offset by timely transplantation. Longer follow
up and an assessment of the functional status of these patients is required to
assess whether or not this complex surgical approach is indeed warranted.
PMID- 9755004
TI - Post cardiac surgery phrenic nerve palsy: value of plication and potential for
recovery.
AB - OBJECTIVES: Evaluation of an aggressive policy for the treatment of phrenic nerve
palsy (PNP), following cardiac operations, with emphasis on early diaphragmatic
plication. Attention was given to the incidence and predisposing factors for PNP
and the potential for recovery following plication. METHODS: From 1 June 1991 to
1 January 1996 we prospectively screened patients for PNP following cardiac
surgery. The diagnosis was suspected if difficulty was experienced in weaning the
child from the ventilator. If abnormal elevation of the hemidiaphragm was present
diaphragmatic plication was performed. Echocardiography was used to assess
subsequent return of diaphragmatic function. RESULTS: Seventeen children (nine
boys, eight girls), out of 867 (1.9%) children younger than 16 years of age,
undergoing cardiac operations were found to have PNP. The mean age was 66 days
(range 1-17 months) with 16 patients below 1 year out of a total of 285 patients
(incidence 5.6%) and one patient 17 months old. The incidence following open
procedures was 11/190, following closed procedures 2/95 and following reoperation
4/83. PNP was diagnosed from 2 to 44 days (mean 14 days) following surgery. It
was present on the right side in seven cases, the left in nine and was bilateral
in one patient. Two patients were extubated at the time of diagnosis, one patient
could be extubated shortly thereafter. Fourteen children underwent diaphragmatic
plication, at a median 5 days post diagnosis. Extubation was possible 1-60 days
(mean 4 days) after plication. Mean follow-up was 19 +/- 5 months. Subsequent
recovery of diaphragmatic movement was documented in seven (41%) children. Time
to recovery following plication was 16 months, without plication 38 months.
CONCLUSION: Prospective screening for PNP revealed an incidence in children
younger than 1 year of 6%. Early plication substantially reduces the duration of
ventilation, with its associated reduced morbidity and ICU stay.
PMID- 9755005
TI - Aspartate improves recovery of the recently infarcted rat heart after
cardioplegic arrest.
AB - BACKGROUND: We have previously shown that aspartate improves the tolerance of
normal hearts to cardioplegia. The aim of this study was to investigate whether
aspartate is also beneficial in the recently infarcted heart. METHODS: Myocardial
infarction was produced in rats by left coronary artery ligation. Twenty hours
later their hearts were perfused on an isolated working rat heart apparatus and
underwent cardioplegic arrest for 30 min at 37 degrees C with or without 20 mM
aspartate in the cardioplegic solution (n = 11 per group). Functional recovery
and myocardial high energy phosphate levels were measured at the end of arrest
and after 30 min of reperfusion. RESULTS: There was no difference in pre-arrest
pump function between the untreated and aspartate-treated groups. However, after
reperfusion the aspartate group generated more power (3.4 +/- 0.2 mJ/s per g)
than the untreated group (2.5 +/- 0.3 mJ/s per g; P < 0.05) such that the
percentage recovery of pre-arrest power in the aspartate group (67.7 +/- 3.5%)
was greater than in the untreated group (53.6 +/- 4.9%; P < 0.05). The aspartate
group also showed increases in aortic flow and myocardial oxygen consumption
compared to the untreated group (P < 0.05). There were no between-group
differences in high energy phosphate levels at the end of arrest or after
reperfusion. CONCLUSION: Aspartate improves functional recovery of the recently
infarcted heart during cardioplegic arrest, and therefore has potential as a
useful adjunct to myocardial protection in patients with recent myocardial
infarction undergoing cardiac surgery.
PMID- 9755006
TI - Lung transplantation for cystic fibrosis--a single center experience over 8
years.
AB - OBJECTIVE: Colonization of the lung and mediastinal lymph nodes with multi
resistant bacteria, diabetes and malnutrition represent potential risk factors
for lung transplantation in cystic fibrosis. We therefore reviewed our experience
in this patient population. METHODS: Between December 1988 and March 1997, 219
lung and heart-lung transplantations were performed at our institution. Of these,
39 procedures were done in 35 patients with cystic fibrosis. All candidates (mean
age 26 years) were oxygen dependent (preoperative mean PO2: 44.8 +/- 9.1 Torr,
preoperative mean PCO2: 53.4 +/- 10.5 Torr, one patient on respirator). Of the
primary operations, 34 were performed as bilateral sequential lung transplants,
one as a heart-lung transplantation. RESULTS: Mean duration on respirator for
survivors was 3.1 (1-12) days, mean ICU and hospital stay were 4.7 (1-13) and 28
(12-79) days, respectively. The 3-month mortality rate was 5.7% (two patients
died due to acute graft failure on days 36 and 73). Other causes of death in the
follow-up were cerebral bleeding (one patient) and chronic graft failure (three
patients). The survival rates were 91% at 1 year, 83% at 3 years and 76% at 5
years. In eight patients, a bronchiolitis obliterans syndrome (BOS) developed (in
four cases grade 3). The freedom of BOS (grade 1 or more) at 1, 3 and 5 years was
87, 79 and 55%, respectively. Four retransplantations were performed. Of the 29
patients alive, only seven are physically limited. CONCLUSION: Bilateral lung
transplantation for cystic fibrosis allows for acceptable early- and long-term
results. Postoperative survival is not impaired by infection, diabetes and
malnutrition. Long-term functional outcome seems to be comparable to lung
transplantation in patients without infectious pulmonary disease.
PMID- 9755007
TI - Vascular rejection post heart transplantation is associated with positive flow
cytometric cross-matching.
AB - OBJECTIVE: Use of flow cytometry cross-matching for measurement of donor-specific
alloreactivity and monitoring anti-donor antibodies is well established. This
study was performed to determine (1) its accuracy as a marker of vascular
rejection, (2) its correlation with post-transplant outcome and (3) its ability
to monitor highly sensitized patients requiring antibody removal with plasma
exchange. METHODS: Serial serum samples from 99 heart transplant recipients were
examined for the presence of anti-donor antibodies of the IgG class that were
reactive with T and/or B cryopreserved donor lymphocytes. A sub-group of 20 HLA
sensitized patients required plasma exchange to remove the anti-HLA antibodies
and were monitored with flow cytometry cross-matching to assess the degree of
antibody removal. RESULTS: Positive T-cell reactions were observed in 26 patients
and positive B-cell reactions in 54. Twenty patients had vascular rejection. A
significantly larger number of patients with a positive flow cytometry cross
match had vascular rejection (42% versus 12% for T-cell reactions, and 32% versus
7% for B-cell reactions; P = 0.002 each). Of the patients who had vascular
rejection, 11 had a positive T-cell reaction (flow cytometry cross-match
sensitivity of 55%), and 17 had a positive B-cell reaction (sensitivity of 85%).
Of the 79 patients who did not develop vascular rejection, 64 had a negative T
cell reaction (specificity of 81%), and 42 had a negative B-cell reaction
(specificity of 53%). The actuarial 2-year survival estimates were significantly
higher in patients with negative T-cell reactions (90% versus 75%; P = 0.04), and
B-cell reactions (95% versus 78%; P = 0.02). In the highly sensitized subgroup (n
= 20) the effectiveness of plasma exchange to decrease anti-HLA antibody
reactivity was a strong predictor of outcome. For patients in whom plasma
exchange (PE) reduced anti-donor reactivity, 1-year survival was 87% compared to
25% in those whom PE did not reduce the level of antibody binding as assessed
with flow cytometry cross-matching (P < 0.0001). CONCLUSIONS: Flow cytometry
cross-matching provides a valuable marker for the detection of vascular rejection
after cardiac transplantation. Quantitative measurements may allow evaluation of
the efficacy of treatment modalities employed in the management of vascular
rejection in an attempt to improve outcome.
PMID- 9755008
TI - Reduced renal failure following thoracoabdominal aortic aneurysm repair by
selective perfusion.
AB - OBJECTIVES: Renal failure and visceral ischemia are feared complications
following thoracoabdominal aortic aneurysm (TAAA) repair, significantly
contributing to mortality. This prospective study describes volume- and pressure
controlled perfusion of the renal and visceral arteries during TAAA surgery.
METHODS: In 73 consecutive patients (mean age 59 years), TAAA repair (27 type I,
28 type II, 8 type III and 10 type IV) was performed, using retrograde and
selective organ perfusion. Sixteen patients had impaired renal function with
blood creatinine higher than 100 mmol/l. During the thoracic part of the
procedure, the mean distal aortic pressure was kept above 60 mm Hg by means of
left-heart bypass. After opening the abdominal aorta, the renal and visceral
arteries were individually perfused by means of perfusion catheters (9 French) in
the first 33 patients (group I). Volume flow through each catheter was assessed
with ultrasound flow meters and maintained at least at 60 ml/min. In addition to
volume flow measurements, catheters with pressure sensors were used in the last
40 patients (group II), allowing pressure-controlled selective perfusion. The
extent of the aneurysm was comparable in both groups. RESULTS: Mean cross-clamp
time for the thoracic part was 46 min, including proximal anastomosis and
reattachment of intercostal arteries. Mean cross-clamp time for the abdominal
part was 74 min, including re-implantation of intestinal and renal arteries and
selective dacron grafts to the celiac-axis arteries (n = 5), superior mesenteric
arteries (n = 8) and renal arteries (n = 25), through which the catheters
guaranteed continuous perfusion during the time the anastomosis was performed.
Urine output was uninterrupted in all patients, irrespective of cross-clamp time.
In group I, one patient (3%) developed renal failure and three patients (9%)
required temporary peritoneal dialysis. In group II, no patients developed renal
failure and two patients (5%) required temporary peritoneal dialysis. Thirteen
patients with pre-existing renal impairment did not deteriorate. No patients
developed visceral ischemia or multiple-organ failure. Total in-hospital
mortality was 6/73 (8%) and was related to cardiopulmonary complications.
CONCLUSIONS: Renal and visceral ischemia can be reduced significantly by
continuous perfusion during cross-clamping in TAAA repair. Not only sufficient
volume flow but also adequate arterial pressure appears to be essential in
maintaining renal function.
PMID- 9755009
TI - The conventionally ventilated operating theatre and air contamination control
during cardiac surgery--bacteriological and particulate matter control garment
options for low level contamination.
AB - OBJECTIVE: The purpose of the study was to compare the usefulness of a
conventional bacteriological technique with that of particle counting under lower
air contamination and better aseptic conditions achieved with special staff
garments and covering for the patient. Contamination levels were estimated with
continuous on line air particle counting measurement, volumetric intermittent
short period aerobic bacteriological cultures and wound surface contact cultures.
METHODS: In a series of 66 consecutive coronary artery bypass operations
performed by the same team and in the same theatre using different types of
patient and staff clothing, the impact of a reduced bacteriological and
particulate contamination were assessed. The volumetric air contamination of
particles > or =5 microm and bacteria-carrying particles were monitored 30 cm
above the sternal wound. The bacterial contamination and bacterial wound
infections in the sternal and leg wounds were assessed as well. RESULTS: With the
alternative garment and textile system, the air counts fell from 25 colony
forming units (CFU)/m3 to 7 CFU/m3 (P < 0.0038). The contamination of the sternal
wound was reduced by 46% and that of the leg wound by >90%. In order to give
continuous contamination feedback during the whole operation to the theatre
staff, particle counts > or =5 microm were monitored and visualized. Air particle
counts decreased rapidly from 850 particles/m3 and stabilized to approximately 50
particles/m3 when the alternative clothing system was used (P < 0.001). Low
particle counts > or =5 microm should offer the possibility to indirectly
estimate air bacteria carrying particle counts during the entire operation. Less
than 20% of the total count in this size group carries bacteria. The low air
contamination was achieved even in an ordinary ventilated theatre when individual
team members used clean air suits in combination with impermeable patient drapes.
When air particle level < or =50 particles/m3 is reached, the bacterial air
contamination is in the order of that of orthopaedic hip operations. The staff
must during the entire operation adjust their activity to air asepsis.
CONCLUSIONS: The use of clean air suits and impermeable patient clothing results
in a low exogenous contamination of air and wound. Continuous air particle
monitoring is a good intraoperative method to monitor the air contamination
longitudinally in an operating theatre.
PMID- 9755010
TI - A case of giant benign localized fibrous tumor of the pleura.
AB - A 60-year-old man had noted exertional dyspnea and left anterior chest pain. A
chest roentgenogram showed the presence of a giant mass and computed tomography
(CT) of the chest confirmed the mass with an inhomogeneous density in the left
hemithorax. A transthoracic TruCut needle biopsy of the mass showed benign
fibrous tissue. The patient underwent a thoracotomy. A tumor arose from the
visceral pleura of left lower lobe and pedinculated. Size of the tumor was 19 x
18 x 7 cm and weighed 1500 g. It was successfully resected. The pathological
diagnosis of the tumor was benign localized fibrous tumor of the pleura.
PMID- 9755011
TI - Repair of aortico-right ventricular tunnel.
AB - Aortico-right ventricular tunnel was successfully corrected in a 15-month-old
child. Both the aortic and right ventricular openings were closed with pledgeted
sutures. The coronary artery anatomy was normal. At 12-month follow-up the
patient is in excellent clinical condition. Before surgical intervention for
aortico-right ventricular tunnel is undertaken, every effort should be made to
diagnose the coronary artery anatomy, because failure to do so in the case of
aberrant origin of a coronary artery may prevent successful surgical correction.
PMID- 9755012
TI - The effectiveness of diaphragmatic pedicled grafts in esophageal injuries and
wall reconstruction.
PMID- 9755013
TI - The clinical course and prognostic factors of non-specific neck pain: a
systematic review.
AB - Neck pain occurs frequently in western societies. In the majority of cases, no
specific cause can be identified. In order to gain insight into the clinical
course and prognostic factors of non-specific neck pain, a systematic review was
conducted. A computerized literature search was carried out to identify
observational studies on non-specific neck pain and randomized clinical trials
(RCTs) on conservative treatment of non-specific neck pain. Two reviewers scored
independently, the methodological quality of all identified publications, using a
standardized set of 13 criteria which were divided into five categories according
to: study population, study design, follow-up, outcome measures and analysis/data
presentation. To determine prognosis per study, an overall percentage of recovery
for the most important outcome measures (pain, general improvement, functional
status, health care utilization and lost days of work) was calculated. In total
23 eligible publications were identified (six observational studies and 17 RCTs).
Only seven of 23 studies scored 50% or more of the 13 items, indicating a
generally poor quality of methods. The most prevalent methodological shortcomings
appeared to be selection of the study population, the sample size and analysis
techniques. Most information regarding the clinical course is available for the
group of patients with complaints for more than 6 months, who are treated in a
secondary care or an occupational setting. In this group of patients, 46%
(median) had less pain, with a range of 22-79% and a general improvement that
ranged between 37 and 95% (47% median). The reduction in the use of analgesics
ranged between 32 and 80% (37% median). Six studies reported on prognostic
factors. Bearing in mind the limited number of studies and the low methodological
quality, there are some indications that the localization (radiation to the
arms/neurologic signs) and radiologic findings (degenerative changes in the discs
and joints) are not associated with a worse prognosis. A higher severity of pain
and a history of previous attacks however, seems to be associated with a worse
prognosis.
PMID- 9755014
TI - An experimental model for chronic compression of dorsal root ganglion produced by
intervertebral foramen stenosis in the rat.
AB - Under anesthesia and sterile surgery, a small stainless steel rod (4 mm in length
and 0.5-0.8 mm in diameter) was inserted into the L5 intervertebral foramen in
the rat, developing intervertebral foramen stenosis and hence producing a chronic
steady compression of the dorsal root ganglion (DRG). The hind paw on the injured
side exhibited a significant reduction in the latency of foot withdrawal to
noxious heat and manifested a persistent heat hyperalgesia 5-35 days after
surgery. Injection of 1% carrageenan into the intervertebral foramen, presumably
causing inflammation of the DRG, also produced hyperalgesia to heat on the hind
paw of the injured side 5-21 days after surgery. Extracellular
electrophysiological recordings from myelinated dorsal root fibers were performed
in vivo. Spontaneous activity was present in 21.5% of the fibers recorded from
DRG neurons injured with chronic compression in contrast to 1.98% from uninjured
DRG neurons. The pattern of spontaneous activity was periodic and bursting in
75.3% of the spontaneously active fibers. These neurons had a greatly enhanced
sensitivity to mechanical stimulation of the injured DRG and a prolonged after
discharge. In response to TEA, topically applied to the DRG, excitatory responses
were evoked in the injured, but not the uninjured, DRG neurons. Application of
this experimental model may further our understanding of the neural mechanisms by
which chronic compression of DRG induces low back pain and sciatica.
PMID- 9755015
TI - The relationship between gender and family history of pain with current pain
experience and awareness of pain in others.
AB - This study aimed to evaluate the relationship between family history of pain and
current pain experience in a student population. In a sample of 180 students who
completed a pain history questionnaire there was a significant difference between
males and females with women reporting significantly more pain models than men
even when menstrual pain models were excluded from the analysis. There was also a
difference on current pain symptoms, with women reporting more pain symptoms but
this difference was no longer significant when menstrual pain was excluded. These
results suggest that differences observed between sexes in a young student
population in relation to current pain symptom reports may be accounted for by
the presence of menstrual pain rather than by differences in family history of
pain as it has previously been suggested. The higher incidence of pain models
reported by females for menstrual as well as non-menstrual pain suggests a
greater awareness of pain in others without implying a greater tendency for the
young females as a group to report pain themselves.
PMID- 9755016
TI - Pain coping strategies predict perceived control over pain.
AB - Perceptions of control over pain and specific pain coping strategies are
associated with a number of positive outcomes in patients with chronic pain
conditions. Transactional models of stress have emphasized coping as a process
that is both determined by, and influences appraisals of control. While
perceptions of control and coping efforts are associated with better adjustment,
little is known about the specific coping strategies that contribute to
perceptions that pain is controllable. One hundred and ninety-five (65% female)
individuals with chronic pain conditions admitted to an inpatient unit completed
the Multidimensional Pain Inventory, the Survey of Pain Attitudes and the Coping
Strategies Questionnaire. Stepwise multiple regression analyses were used to
predict perceived pain control from measures of pain severity and coping. After
controlling for pain severity and education, coping self-statements and
reinterpreting pain sensations predicted greater perceptions of control over
pain, whereas ignoring pain sensations predicted lower perceptions of control
over pain. The coping strategies did not interact with pain severity in
predicting perceptions of control. Coping flexibility, or the number of pain
coping strategies reported at a high frequency, also predicted perceptions of
control over pain and did not interact with pain severity. The present findings
suggest that, regardless of pain severity, the use of specific cognitive pain
coping strategies may increase perceptions of control over pain. Since the
existing coping literature largely identifies maladaptive pain coping strategies,
it is especially critical to establish which pain coping strategies are adaptive.
Specific cognitive strategies, particularly coping self statements, are important
components for cognitive-behavioral interventions for chronic pain management.
Future research will need to determine whether other adaptive cognitive
strategies such as reinterpreting pain sensations can be increased with cognitive
interventions, since this strategy is infrequently used.
PMID- 9755017
TI - The physical and psychological experience of pain: the effects of labeling and
cold pressor temperature on three pain measures in college women.
AB - Using the cold pressor test, three experiments were conducted to investigate the
effects of water temperature and labeling on three dependent measures in college
women: behavioral pain tolerance (BPT), a sensory rating of the pain experience
(SR) and a parallel affective rating of the experience (AR). Temperature of the
cold pressor was varied as the physical factor; labels (discomfort, pain,
vasoconstriction pain) were varied as the psychological factor. Experiment I
varied only water temperature; colder temperatures led to significantly lower BPT
scores and significantly higher SR and AR scores. Experiment 2 varied only
labeling and demonstrated that BPT decreased and AR increased as labels became
more painful-sounding; in contrast, SR was unaffected by labeling. In Experiment
3 both the psychological and physical factors were varied simultaneously. Results
indicated significantly higher BPT scores as the water temperature increased and
the pain label became more benign. In addition, both SR and AR were sensitive to
changes in temperature, whereas only AR was affected by changes in labeling.
PMID- 9755018
TI - Morphine, the NMDA receptor antagonist MK801 and the tachykinin NK1 receptor
antagonist RP67580 attenuate the development of inflammation-induced progressive
tactile hypersensitivity.
AB - Normally-innocuous low-intensity tactile stimuli applied to inflamed tissue
induce a progressive decrease in the mechanical flexion withdrawal threshold, the
phenomenon of progressive tactile hypersensitivity (PTH). The effects of the mu
opioid receptor agonist morphine, the non-competitive NMDA receptor antagonist
MK801 and the tachykinin NK1 receptor antagonist RP67580 on the development and
maintenance of PTH has now been investigated behaviourally in rats inflamed 48 h
earlier by intraplantar complete Freund's adjuvant injection. A standard protocol
of eight light tactile stimuli applied to the dorsum of the inflamed paw every 4
s at 5 min intervals resulted, over 60 min, in a 70% fall in mechanical threshold
from the pre-conditioning baseline value. Morphine administered before the
tactile stimuli at 0.05 mg/kg i.p. had no effect on either baseline thresholds or
PTH. At 0.5 mg/kg, morphine prevented the establishment of PTH without changing
baseline thresholds. At 5 mg/kg morphine produced analgesia, increasing
thresholds above the baseline. MK801 pre-treatment at 0.01 and 0.001 mg/kg i.p.
significantly attenuated the development of progressive tactile hyperalgesia
without an effect on basal thresholds. RP67580 pre-treatment at 0.1 mg/kg i.p.
had no effect, but at both I and 10 mg/kg, attenuated progressive tactile
hypersensitivity without changing baseline values. To test the effect of the
drugs on established PTH, they were administered 90 min after the commencement of
intermittent tactile stimulation to the inflamed hindpaw, when thresholds had
reached a plateau. Morphine (0.5 mg/kg) and MK801 (0.01 mg/kg) produced only a
small reduction in sensitivity and RP67580 (1 mg/kg) had no effect. These results
suggest that the induction of inflammatory progressive tactile hypersensitivity
is sensitive to morphine, and to a lesser extent NMDA and NKI receptor
antagonists, but these compounds at a dose that do not alter baseline values, do
not normalise established tactile hypersensitivity.
PMID- 9755019
TI - Intrathecal administration of the mGluR compound, (S)-4CPG, attenuates
hyperalgesia and allodynia associated with sciatic nerve constriction injury in
rats.
AB - The present study examined the effects of intrathecal (i.t.) treatment (twice
daily injections on post-operative (PO) days 0-8) with the metabotropic glutamate
receptor (mGluR) compound, (S)-4-carboxyphenylglycine ((S)-4CPG), or the non
competitive N-methyl-D-aspartate (NMDA) antagonist, dizocilipine maleate (MK
801), on mechanical allodynia and cold hyperalgesia associated with chronic
constriction injury (CCI) of the sciatic nerve in rats. Also, the effects of
early (twice-daily injections on days 0-3) or late (twice-daily injections on
days 8-11) (S)-4CPG treatment on the injury-related mechanical allodynia and cold
hyperalgesia were assessed in CCI rats. Results demonstrated that 8-day (S)-4CPG
or MK-801 treatment attenuated mechanical allodynia (up to PO days 12 or 16,
respectively) and cold hyperalgesia (up to PO days 8 or 16, respectively).
Results also demonstrated that early (S)-4CPG treatment significantly attenuated
the development of mechanical allodynia (90 and 270 nmol) and cold hyperalgesia
(270 nmol). However, late treatment with (S)-4CPG did not reduce the nociceptive
behaviours in either behavioural task. These data not only confirm that the NMDA
receptor plays a role in chronic nociception, but also suggest that Group I
mGluRs are more critically involved in the development, and not the maintenance,
of mechanical allodynia and cold hyperalgesia associated with CCI in rats.
PMID- 9755020
TI - Contributing factors to the persistence of musculoskeletal pain in
preadolescents: a prospective 1-year follow-up study.
AB - A 1-year follow-up of two preadolescent age cohorts with musculoskeletal pain at
least once a week was conducted to analyze predictive factors for the persistence
of musculoskeletal pain. Of the 564 children with pain at baseline, representing
one third of the sample studied, 515 (91.3%) could be followed and 452 (80.1%)
children with complete data were included for the logistic regression analysis. A
structured questionnaire included questions on pain and also on several
psychosomatic symptoms and amount of exercise. Joint hypermobility together with
the questionnaire data were included in the logistic regression analysis. One
half of subjects with pain at baseline still reported pain at follow-up,
indicating persistent pain. Boys had a lower risk for the persistence of pain
than girls and the risk for the persistence of pain increased 1.2 times per age
year. When further adjusted for all the other studied risk determinants, high
subjective disability index due to pain (OR 3.2, 95% CI 1.5-6.6) and day
tiredness (OR 1.9, 95% CI 1.2-3.0) were the most significant predictors. This
might indicate that psychological distress contributes to the persistence of non
specific musculoskeletal pain of different locations in preadolescents. In
clinical work not only pain but its interference with daily activities should be
noticed.
PMID- 9755021
TI - Treatment of myofascial trigger-points with ultrasound combined with massage and
exercise--a randomised controlled trial.
AB - The effect of treatment with ultrasound, massage and exercises on myofascial
trigger-points (MTrP) in the neck and shoulder was assessed in a randomised
controlled trial. The outcome measures were pain at rest and on daily function
(Visual Analogue Scale, VAS), analgesic usage, global preference and index of
MTrP. Long-term effect for treatment and control groups was assessed after 6
months using a questionnaire. The patients were randomised to three groups. The
first group was treated with ultrasound, massage and exercise (A), the second
group with sham-ultrasound, massage and exercise (B), while the third group was a
control group (C). The duration of the study was 6 weeks. Treatment was given
twice a week from the second to the fifth week. The number and index of MTrPs
were recorded at each treatment session in groups A and B but only at entry as
well as end of study in group C. VAS and analgesic usage was recorded in all
three groups throughout the study period. Six months after the last treatment
session a questionnaire was send to the patients. A total of 67 patients were
included. Nine patients dropped-out during the study, which left 58 patients that
could be included in the final analysis. Twenty patients were randomised to group
A, 18 to group B and 18 to group C. A significant reduction in index were found
between treatment groups (A and B) and control group (C), but no difference
between group A and B. VAS scores, analgesic usage or global preference showed no
difference between group A, B or C. The patients in the group C were offered
treatment (ultrasound, massage, exercise) after the 6 weeks treatment period. At
the questionnaire after 6 month 44 (87%) of the 52 patients from all three groups
who had treatment responded. Sixty-four percent answered that they had had good
or some effects, 68 percent were still doing the exercise programme and 17
percent had received other forms of therapy after they had completed the study.
No difference between groups given ultrasound or sham ultrasound were found. It
is concluded that US give no pain reduction, but apparently massage and exercise
reduces the number and intensity of MTrP. The impact of this reduction on neck
and shoulder pain is weak.
PMID- 9755022
TI - Risk factors for back pain incidence in industry: a prospective study.
AB - The objective of this study was to examine the relationship between physical and
psychological risk factors on the one hand, and the occurrence of new episodes of
back pain on the other hand. A prospective study was conducted with 12 months
follow-up by means of self-administered questionnaires. The study took place in
the Cargo Department of a major Dutch airline company. The subjects for this
study were 270 workers involved in heavy physical work. Only workers without back
pain at baseline were included. Self-reported back pain and sick leave due to
back pain during the follow-up period were measured. Of the 238 workers included
in the analysis, 73 (31%) developed a new episode of back pain during the follow
up period, and 27 (11%) subjects reported sick leave due to back pain. Multiple
logistic regression analysis showed that the history of back pain was the best
predictor for the occurrence of a new episode of back pain during follow-up (OR
9.8; 95% CI 2.8-34.4 for subjects who had back pain more than twice in the past
year). Low job satisfaction was also associated with an increased risk for the
occurrence of back pain during follow-up (OR 1.2; 95% CI 1.01-1.4). Riding a
forklift truck appeared to be a protective factor for the occurrence of back pain
(OR 0.7; 95% CI 0.5-0.99). In this study the best predictors for the occurrence
of back pain were the history of back complaints and low job satisfaction.
Although it needs to be confirmed by future intervention studies, the results
indicate that increasing job satisfaction may be a successful (co-)intervention
for the prevention of back pain at the workplace.
PMID- 9755023
TI - Milacemide, a glycine pro-drug, inhibits strychnine-allodynia without affecting
normal nociception in the rat.
AB - The blockade of spinal glycine receptors with intrathecal (i.t.) strychnine (STR)
produces reversible, segmentally localized allodynia in the rat. The purpose of
this study was: (1) to investigate the effect of the anticonvulsant agent,
milacemide, a glycine pro-drug on STR-allodynia; (2) to compare this effect with
that of milacemide on normal nociception (without STR); and (3) to determine the
sensitivity of the anti-allodynic effect of milacemide to pretreatment with
selective monoamine oxidase (MAO)-A (clorgyline) and MAO-B (L-deprenyl)
inhibitors. Male Sprague-Dawley rats, fitted with chronic i.t. catheters, were
lightly anesthetized with urethane. Hair deflection (HD) evoked maximum changes
in blood pressure and heart rate were recorded from left carotid artery, and
cortical electroencephalographic (EEG) activity was continuously monitored using
subdermal needle electrodes before and after i.t. STR (40 microg). Rats were
pretreated with a single intravenous (i.v.) injection of milacemide (100-600
mg/kg), 1 h before i.t. STR. To sustain the allodynic state, STR was injected
every hour for up to 4 h. HD was applied to the affected dermatomes (2 min
duration) using a cotton-tipped applicator at 5-min intervals for the duration of
the STR effect. Normally innocuous HD elicited a marked increase in mean arterial
blood pressure and heart rate, an immediate motor responses, and
desynchronisation of EEG when applied to the cutaneous dermatomes affected by
i.t. STR. Milacemide (100-600 mg/kg, i.v.) dose-dependently inhibited the heart
rate and pressor responses (ED50 = 398 mg/kg; 95%CI = 196-873) and the motor
responses (ED50 = 404 mg/kg; 95%CI = 275-727). Maximum inhibition was observed
approximately 2 h after i.v. injection. The duration of action ranged from 3 h
(400 mg/kg) to 4 h (600 mg/kg). Milacemide had no effect on the percent synchrony
in the EEG. At the time of maximum inhibition of STR-allodynia (2 h post
infusion), responses evoked by noxious pinch were unaffected by milacemide.
Pretreatment with L-deprenyl (3 mg/kg, i.p.), but not clorgyline (10 mg/kg, i.p.)
significantly blocked the anti-allodynic effect of milacemide (600 mg/kg i.v).
These data indicate that i.v. milacemide significantly attenuates the allodynia
arising from spinal glycine receptor blockade, and are consistent with: (1) the
selective modulation of low threshold afferent input by STR-sensitive, glycine
interneurons in the rat spinal cord; and (2) the pharmacological actions of
milacemide as a glycine pro-drug.
PMID- 9755024
TI - Treatment with either high or low frequency TENS reduces the secondary
hyperalgesia observed after injection of kaolin and carrageenan into the knee
joint.
AB - For years, physical therapists have been utilizing a variety of modalities,
including transcutaneous electrical nerve stimulation (TENS), in an attempt to
manage pain associated with inflammation. However, the data on clinical
effectiveness is conflicting and the neurophysiological mechanism of action is
not known. The purpose of this study was to investigate the effects of high and
low frequency TENS on the secondary hyperalgesia that occurs after joint
inflammation. Secondary hyperalgesia is thought to reflect changes in central
neurons and is thus a measure of activity of central neurons. This study utilized
the kaolin and carrageenan model of knee joint inflammation and measured the
effects of TENS treatment on paw withdrawal latency to radiant heat (secondary
hyperalgesia), spontaneous pain behaviors and joint circumference. Either high
(100 Hz) or low (4 Hz) frequency TENS was applied to the knee joint for 20 min
after the development of hyperalgesia. Both high and low frequency TENS resulted
in a reversal of the hyperalgesia immediately following treatment. The effects of
high frequency TENS lasted through at least 24 h while those of low frequency
TENS lasted through 12 h. There was no effect of TENS on spontaneous pain
behaviors or joint swelling when compared to controls. Thus, TENS appears to be
more effective in reducing referred pain (or secondary hyperalgesia) without
affecting guarding or splinting of the affected limb. Thus, clinically, the
choice to use TENS may depend on patient symptoms; specifically TENS should be
effective in reducing referred or radiating pain.
PMID- 9755025
TI - Comment on Manfredi et al.,Pain, 70 (1997) 199-101.
PMID- 9755026
TI - The seasonal interrelationship between melatonin, vasopressin, and serum
osmolality in elderly subjects.
AB - Plasma concentration of arginine vasopressin (AVP) and melatonin and serum
osmolality were measured at noon and at midnight in individuals living in the
northern hemisphere on March 22-23, June 13-14, September 26-27, and December 12
13 in 35 healthy volunteers (15 men and 20 women) aged 60-74 years. The nocturnal
increase in melatonin was highest in the autumn and lowest in the winter in both
sexes. The midnight serum osmolality level was lower in the autumn than in any
other time of the year. In both the men and the women the AVP level was higher in
winter than in any other season (P < 0.01 and P < 0.0001, respectively). In men,
the AVP level was higher at noon than at midnight in 49% of the investigated 24
hr periods, at the same level in 15% and lower in 36% (NS). The corresponding
figures for women were 55%, 25%, and 20%, respectively (P < 0.05). This study
suggests a possible relationship between melatonin and serum osmolality.
PMID- 9755027
TI - Circadian secretion patterns of melatonin after major surgery.
AB - Biorhythms, such as regular variation in core body temperature and the pattern of
the secretion of melatonin, are thought to be mediated by the same biological
clock. Core body temperature is affected by the inflammatory response to major
surgery. Apart from the well-known inhibitory effect of bright light on its
secretion, melatonin is an exceedingly good marker of one of the central
generating systems of circadian rhythms. We sequentially measured the plasma
melatonin concentration pattern in patients who had undergone esophagectomy with
thoracotomy to elucidate the circadian rhythm after major surgery. From seven
patients who had received esophagectomy with thoracotomy for esophageal cancer,
plasma concentrations of melatonin were measured using an RIA method. Blood
samples were collected via each patient's arterial line at 00.00, 02.00, 04.00,
06.00, 08.00, 12.00, 16.00, 20.00, and 24.00 hr on the first postoperative day
for six of the patients, and, for one patient, every 2 hr until the third
postoperative day and every 4 hr thereafter until the sixth postoperative day.
Four patients out of seven had melatonin concentrations of over 30 pg/ml (mean 34
pg/ml) at 24.00 hr on the first postoperative day. Five patients showed circadian
secretion patterns of melatonin during the first postoperative day. One patient
whose melatonin concentrations were measured consecutively for 6 days showed a
regular circadian secretion pattern through the 6 days of the study. Even the
stress caused by extremely invasive surgery did not significantly disturb the
melatonin secretion pattern.
PMID- 9755028
TI - Protective effect of melatonin on cellular energy depletion mediated by
peroxynitrite and poly (ADP-ribose) synthetase activation in a non-septic shock
model induced by zymosan in the rat.
AB - DNA single-strand breakage and activation of the nuclear enzyme poly (ADP-ribose)
synthetase (PARS) triggers an energy-consuming, inefficient repair cycle, which
contributes to peroxynitrite-induced cellular injury. Recently it was proposed
that zymosan, a non-bacterial agent, causes cellular injury by inducing the
production of peroxynitrite and consequent PARS activation. Here we investigated
whether in vivo melatonin treatment inhibits cellular injury induced by
peroxynitrite production and PARS activation in macrophages collected from rats
subjected to zymosan-induced shock. Macrophages harvested from the peritoneal
cavity exhibited a significant production of peroxynitrite, as measured by the
oxidation of the fluorescent dye dihydrorhodamine 123. Furthermore, zymosan
induced shock caused a suppression of macrophage mitochondrial respiration, DNA
strand breakage, activation of PARS and reduction of cellular levels of NAD+. In
vivo treatment with melatonin (25 and 50 mg/kg, intraperitoneally, 1 hr after
zymosan injection) significantly reduced in dose-dependent manner peroxynitrite
formation and prevented the appearance of DNA damage, the decrease in
mitochondrial respiration, the loss of cellular levels of NAD+, and the PARS
activation. Our study supports the view that the antioxidant and antiinflammatory
effect of melatonin is also correlated with the inhibition of peroxynitrite
production and PARS activation. In conclusion, melatonin may be a novel
pharmacological approach to prevent cell injury in inflammation.
PMID- 9755029
TI - Protective role of melatonin and retinol palmitate in oxidative stress and
hyperlipidemic nephropathy induced by adriamycin in rats.
AB - We have studied the effects of melatonin and retinol palmitate (RP) on the
nephropathy and oxidative stress induced by a single and high dose of adriamycin
(AD) in Wistar male rats. A dose of melatonin (75 microg/kg/day) and a dose of RP
(0.25 g oily solution/kg/day, s.c.) were injected 3 and 9 days before and after
the administration of AD (25 mg/kg, i.p.), respectively. After the decapitation,
samples were taken from the neck vascular trunk in order to determine the
triglycerides, total cholesterol, phospholipids, HDL-cholesterol, total proteins,
urea, lipoperoxides, and reduced glutathione (GSH). We estimated the lipoperoxide
and glutathione (GSH) contents in renal homogenates, and the excretion of
proteins in urine over a 24 hr period. The administration of AD caused
significant increases in proteinuria and in the other parameters studied [lipids
(triglycerides, total cholesterol, phospholipids, and HDL-cholesterol), non
protein nitrogen compounds, and lipoperoxides]. AD increased the lipoperoxide
content, but it decreased the GSH content in the kidney. Both melatonin and RP,
although melatonin more significantly, decreased the intensity of the changes
produced by the administration of AD alone. In fact, melatonin was quite
efficient in reducing the formation of lipoperoxides, restoring renal GSH content
and decreasing remarkably the severity of proteinuria. These results support the
powerful antioxidant action of melatonin at renal level and a lower antioxidant
action of retinol. Likewise, these data reinforce the hypothesis which supports
the pathogenetic role and the close relation between the oxidative stress and the
expression of the nephropathy induced by AD. However, in spite of this obvious
antioxidant effect of melatonin in the kidney, additional studies are required to
establish accurately the role of this pineal indole in the regulation and
dynamics of the antioxidative defense enzyme system, which neutralizes the
damaging effect of free radicals, both endogenous and exogenous, in this organ.
PMID- 9755030
TI - Oxidative stress in diabetic rats induced by streptozotocin: protective effects
of melatonin.
AB - We have studied the effect of the administration of two doses of melatonin
(melatonin 100 and melatonin 200 microg/kg bw) on diabetes and oxidative stress
experimentally induced by the injection of streptozotocin (STZ) in female Wistar
rats. STZ was injected as a single dose (60 mg/kg i.p. in buffered citrate
solution, pH 4.0) and melatonin (melatonin 100, 100 microg/kg/day i.p.; melatonin
200, 200 microg/kg/day i.p.) beginning 3 days before diabetes induction and
continuing until the end of the study (8 weeks). The parameters analysed to
evaluate oxidative stress and the diabetic state were a) for oxidative stress,
changes of lipoperoxides (i.e., malondialdehyde, MDA) in plasma and erythrocytes
and the changes in reduced glutathione (GSH) in erythrocytes and b) for diabetes,
changes in glycemia, lipids (triglycerides: TG; total cholesterol: TC; HDL
cholesterol, HDL-c), percentage of glycosylated hemoglobin (Hb%), and plasma
fructosamine. The injection of STZ caused significant increases in the levels of
glycemia, percentage of glycosylated hemoglobin, fructosamine, cholesterol,
triglycerides, and lipoperoxides in plasma and erythrocytes, whereas it decreased
the levels of HDL-c and the GSH content in erythrocytes. The melatonin 100 dose
reduced significantly all these increases, except the percentage of glycosylated
hemoglobin. With regard to the decreases of plasma HDL-c and GSH content in
erythrocytes, this melatonin dose returned them to normal levels. The melatonin
200 dose produced similar changes, though the effects were especially noticeable
in the decrease of glycemia (55% vs. diabetes), percentage of hemoglobin (P <
0.001 vs diabetes), and fructosamine (31% vs. diabetes). This dose also reversed
the decreases of HDL-c and GSH in erythrocytes. Both doses of melatonin caused
significant reduction of the percentage of glycosylated hemoglobin in those
groups that were non-diabetic. These illustrate the protective effect of
melatonin against oxidative stress and the severity of diabetes induced by STZ.
In particular, this study confirms two facts: 1) the powerful antioxidant action
of this pineal indole and 2) the importance of the severity of oxidative stress
to maintain hyperglycemia and protein glycosylation, two pathogenetic
cornerstones indicative of diabetic complications. Melatonin reduces remarkably
the degree of lipoperoxidation, hyperglycemia, and protein glycosylation, which
gives hope to a promising perspective of this product, together with other
biological antioxidants, in the treatment of diabetic complications where
oxidative stress, either in a high or in a low degree, is present.
PMID- 9755031
TI - Short photoperiod affects reproductive function but not dehydroepiandrosterone
concentrations in male deer mice (Peromyscus maniculatus).
AB - Cessation of breeding is central among the suite of winter-coping strategies used
by small rodents to survive energy-demanding winter conditions. Animals use
photoperiod to predict the onset of winter and initiate, well in advance of
deteriorating conditions, seasonal adaptations. Exposure to short photoperiod
leads to regression of the reproductive system in long-day breeding animals.
Likewise, exposure to short days leads to enhanced immune function among several
rodent species studied. Because dehydroepiandrosterone (DHEA) increases immune
function in virtually all studies reported to date, we sought to determine if
DHEA concentrations might be influenced by photoperiod, thereby suggesting a
mechanism whereby short photoperiod may enhance immune function. Male deer mice
(Peromyscus maniculatus) were exposed to either short or long days for 10 weeks.
Short photoperiods caused significant reduction in all reproductive organs
measured relative to animals housed in long days. However, DHEA concentrations
did not differ between short- and long-day mice. Taken together, these data
suggest that short-day enhancement of immune function in deer mice is independent
of DHEA concentrations.
PMID- 9755032
TI - Changes with age in daytime and nighttime contents of melatonin, indoleamines,
and catecholamines in the pineal gland: a comparative study in rat and Syrian
hamster.
AB - Previous studies in rodents showed a severe deterioration of pineal physiology
with aging. The present study investigated the age-related changes in the content
of monoamines and metabolites in rat and Syrian hamster pineal gland. In addition
to melatonin, the levels of 5-hydroxytryptophan (5HTP), serotonin (5HT), 5
hydroxyindoleacetic acid (5HIAA), N-acetylserotonin (N-Ac-SHT), dopamine (DA),
3,4-dihydroxyphenylacetic acid (DOPAC), and noradrenaline (NA) were measured by
HPLC. Pronounced reductions were found in 5HT and 5HIAA contents during daytime
in rats of 24 months, which had not been observed in animals of 12 months. In
addition, nighttime pineal 5HIAA, N-Ac-5HT, and melatonin contents were decreased
in the old rats, although a significant day:night variation persisted. Also a
diurnal fluctuation in NA, DA, and DOPAC contents was present in young and middle
aged rats but not for NA and DOPAC in the oldest rats due to a decrease in the
nighttime levels. Pineal DA levels were also reduced in 24-month-old rats during
the night, although a marked day:night change was still found. In the Syrian
hamster pineal, significant reductions in daytime 5HT and 5HIAA were found
respectively at 12 and 18 months, while nighttime levels of these compounds were
decreased from 18 months. The nocturnal content of N-Ac-5HT dropped gradually
from 12 months, and melatonin was reduced by 74% and 86% in hamsters of 18 and 24
months, respectively. In all these compounds, a significant day:night variation
was observed irrespective of age. However, neither a day:night variation nor an
effect of aging was found in terms of pineal NA content. In contrast, pineal DA
and DOPAC levels displayed a diurnal variation in hamsters of 1.5 and 6 months,
but not in animals of 12 and 18 months due a reduced nighttime content. These
data suggest that the decline of pineal melatonin with age is a consequence of a
deficit in the pathway of serotonin utilization. This probably is explained by a
reduced N-acetyltransferase activity, which may be linked to impaired pineal
catecholaminergic neurotransmission.
PMID- 9755033
TI - Changes in human plasma melatonin profiles in response to 50 Hz magnetic field
exposure.
AB - The effects of power-frequency magnetic fields on nighttime plasma melatonin were
studied in a group of 30 adult male human subjects. Exposure consisted of 20
microT (200 mG) at 50 Hz (circularly polarized) at certain times in relation to
the predicted time of onset of rise in melatonin concentration for a particular
individual (the time of onset was predicted from a previous screening night).
Response to this exposure was compared to sham-exposure (in random order). When
exposure preceded onset of rise, a significant delay in onset time relative to
sham-exposure of approximately half an hour was observed, with indications
(marginally significant) of a reduction in maximum melatonin level. Analysis of
distribution of time-delays is consistent with two populations: those individuals
who respond (around 20%) and those that do not. Magnetic fields generated by
square-wave currents produce more marked reductions in the maximum level when
compared to sinusoidal waveforms, but there was no significant difference in
onset time.
PMID- 9755034
TI - Axial stiffness of human lumbar motion segments, force dependence.
AB - This paper addresses the axial stiffness of human lumbar motion segments while
subjected to moderate loads. Impacts in axial direction were applied to
Functional Spinal Units while they were subjected to weights acting as static pre
load. Accelerations were recorded proximal and distal of the FSU. The transfer
function and the resonant frequency were calculated from this data. The stiffness
was calculated from the resonant frequency and the load. A simple non-linear
model was fitted to the data and a linear relationship was found between
stiffness squared and force. The non-linear component in the model strongly
affected the stiffness within the chosen load range. The present model may allow
in vivo dynamic force determination with improved accuracy, e.g. in experiments
where accelerometers have been fixated to pins inserted into the spinous
processes of lumbar vertebrae if the static force is known.
PMID- 9755035
TI - One-year changes in hind limb kinematics, ground reaction forces and knee
stability in an experimental model of osteoarthritis.
AB - Long-term changes in the three-dimensional external loading, hind limb kinematics
and knee stability were assessed in an anterior cruciate ligament (ACL)
transected cat model of osteoarthritis (OA). Seven skeletally mature cats (mean
mass 4.6+/-1.4 kg) were studied before ACL transection (ACLT) and at 1 and 3
weeks, and at 3, 6, 9 and 12 months following ACLT. One week following ACLT,
significant changes from the normal locomotion pattern were observed: peak
vertical and anterior posterior ground reaction forces were decreased,
particularly the peak posterior forces in the early phase of stance. Furthermore,
knee angles were reduced by about 15 degrees throughout the whole gait cycle,
while ankle and hip angles were reduced at paw off in the experimental compared
to the contralateral hind limbs. Ground reaction forces and hind limb kinematics
recovered to near pre-surgical patterns over the one year period assessed. ACLT
was also associated with an increased knee instability which improved over time.
X-rays suggested that there was a continued degeneration in the experimental knee
over the one year period; there was osteophyte formation at the joint margins and
an increase in cartilage thickness throughout the joint. It was speculated that
the more flexed knee angles and the reduced anterior-posterior ground reaction
forces in the ACL-transected compared to the intact hind limb represent an
adaptive strategy aimed at avoiding excessive anterior displacement of the tibia
in the early phase of stance. The recovery of the locomotion pattern with time
might be related to the corresponding improvement of knee stability.
PMID- 9755036
TI - Anterior cruciate ligament strain in-vivo: a review of previous work.
AB - Disruption of the anterior cruciate ligament (ACL), a primary stabilizer of the
knee, can produce disability. The purpose of our work has been to study the
normal ACL in humans, in the presence of normal muscle function and body weight,
and develop clinical criteria for reconstruction, establish a basis for
rehabilitation programs, and evaluate how knee braces protect this important
ligament. The strain behavior of the ACL has been measured by arthroscopic
implantation of the Differential Variable Reluctance Transducer while subjects
are under local anesthesia. Movement of the knee from a flexed to an extended
position, either passively or through contraction of the leg muscles, produces an
increase in ACL strain values. Isolated contraction of the dominant quadriceps
with the knee between 50 degrees and extension creates substantial increases in
strain. In contrast, isolated contraction of the hamstrings at any knee position
does not increase strain. With the knee un-weighted, the protective strain
shielding effect of a functional knee brace decreases as the magnitude of
anterior shear load applied to the tibia increases. A different behavior occurs
during weight bearing, the strain shielding effect of the brace remains constant
as the magnitude of anterior load increases. Our approach is novel in that it can
be used to measure on important portion of the ACLs strain distribution while
clinically relevant loads are applied to the knee, subjects perform
rehabilitation exercises, or in the presence of different orthoses such as
functional knee braces.
PMID- 9755037
TI - Asymmetric low back loading in asymmetric lifting movements is not prevented by
pelvic twist.
AB - Asymmetric lifting is associated with an increased risk of low back disorders.
Especially in lifting movements, characterized by a small amount of asymmetry, it
is still the question if asymmetric lumbosacral torques occur, or if subjects try
to avoid asymmetric back loading by twisting their pelvis with respect to the
feet. An increase of the lifting speed or the box weight might amplify the lumbar
torques but might also result in an attempt to limit further increase of
asymmetric torques by increasing pelvic twist. In the current study, asymmetrical
lifting movements were analyzed with the aid of a 3D linked segment model, using
cuffs mounted to the body segments. Eight subjects performed lifting movements
with five different asymmetry conditions, ranging from 0 to 90 degrees lifting
asymmetry with respect to the sagittal plane, using two lifting speeds and two
box weights. A significant increase in lateral flexing and twisting low back
torque was found for each increase in asymmetry of the lifting movement. Pelvic
twist accounted more or less constantly for about 25% of the lifting asymmetry
and was hardly influenced by lifting speed or box weight. Even for 10 or 30
degrees of lifting asymmetry, subjects did not twist their pelvis far enough to
avoid asymmetric loading of the low back. Assuming that asymmetric loading of the
low back is more strenuous to the spine than symmetric loading, the current
results indicate that even small deviations of a lifting movement from the
sagittal plane can explain an increased risk of low back disorders.
PMID- 9755038
TI - Degeneration affects the anisotropic and nonlinear behaviors of human anulus
fibrosus in compression.
AB - Axial and radial specimens of non-degenerate and degenerate human anulus fibrosus
(AF) were tested in confined compression to test the hypothesis that degeneration
significantly affects the compressive properties of AF. Due to the highly
oriented structure of AF, a secondary objective was to investigate anisotropic
behaviors of AF in compression. Uniaxial swelling and stress relaxation
experiments were performed on site-matched samples of anulus from the anterior
outer region of L2-3 intervertebral discs. The experimental stress-relaxation
behavior was modeled using the finite deformation biphasic theory and a finite
difference approximation scheme. Significant effects of degeneration but not
orientation were detected for the reference stress offset, sigma(offset), and
parameters describing the compressive stiffness (i.e. reference aggregate
modulus, H(A0), and nonlinear stiffening coefficient, beta). Average values were
0.13+/-0.06 and 0.05+/-0.05 MPa for sigma(offset), 0.56+/-0.21 and 1.10+/-0.53
MPa for H(A0) and 2.13+/-1.48 and 0.44+/-0.61 for beta for all normal and
degenerate specimens, respectively. No significant effect of degeneration or
orientation were detected for either of the parameters describing the strain
dependent permeability (i.e. reference permeability, k0 and strain-dependent
permeability coefficient, M) with average values for all specimens of 0.20+/-0.10
x 10(-15) m4/N-s and 1.18+/-1.30 for k0 and M, respectively. The loss of
sigma(offset) was compensated with an elastic stiffening and change in the shape
of the equilibrium stress-strain curve with H(A0) for degenerate tissues almost
twice that of normal tissues and beta less than one sixth. The increase in
reference elastic modulus with degeneration is likely related to an increase in
tissue density resulting from the loss of water content. The significant effects
of degeneration reported in this study suggested a shift in load carriage from
fluid pressurization and swelling pressure to deformation of the solid matrix of
the AF. The results also suggest that the highly organized and layered network of
the anulus fibrosus, which gives rise to significant anisotropic effects in
tension, does not play a major role in contributing to the magnitude of
compressive stiffness or the mechanisms of fluid flow of the anulus in the
confined compression configuration.
PMID- 9755039
TI - Static torque-angle relation of human elbow joint estimated with artificial
neural network technique.
AB - Static relations between elbow joint angle and torque at constant muscle activity
in normal volunteers were investigated with the aid of an artificial neural
network technique. A subject sat on a chair and moved his upper- and forearm in a
horizontal plane at the height of his shoulder. The subject was instructed to
maintain the elbow joint at a pre-determined angle. The wrist was then pulled to
extend the elbow joint by the gravitational force of a weight hanging from a
pulley. Integrated electromyograms (IEMGs), elbow and shoulder joint angles and
elbow joint torque were measured. Then the relation among IEMGs, joint angles and
torque was modeled with the aid of the artificial neural network, where IEMGs and
joint angles were the inputs and torque was the output. After back propagation
learning, we presented various combinations of IEMGs, shoulder and elbow joint
angles to the model and estimated the elbow joint torque to obtain the torque
angle relation for constant muscle activation. The elbow joint torque increased
and then decreased with extension of the elbow joint. This suggests that if the
forearm is displaced from an equilibrium point, the torque angle relation would
not act like a simple spring. In a view of the musculoskeletal structure of the
elbow joint, the relation between the elbow joint angle and the moment arm of the
elbow flexor muscles seems to have a dominant effect on the torque-angle
relation.
PMID- 9755040
TI - A Hill type model of rat medial gastrocnemius muscle that accounts for shortening
history effects.
AB - The aim of the present study was to develop a Hill type muscle model that
accounts for the effects of shortening history. For this purpose, a function was
derived that relates force depression to starting length, shortening amplitude
and contraction velocity. History parameters were determined from short-range
isokinetic experiments on rat medial gastrocnemius muscle (GM). Simulations of
isokinetic as well as isotonic experiments were performed with the new model and
a standard Hill type model. The simulation results were compared with
experimental results of rat GM to evaluate if incorporation of history effects
leads to improvements in model predictions. In agreement with the experimental
results, the new model qualitatively described force reduction during and after
isokinetic shortening as well as the experimental observation that isometric
endpoints of isotonic contractions are attained at higher muscle lengths than is
expected from the fully isometric length-force curve. Consequently, the new model
gave a better quantitative prediction of the experimental results compared to the
standard model. It was concluded that incorporation of history effects can
improve the predictive power of a Hill type model considerably. The applicability
of the model to conditions other than those described in the present paper is
discussed.
PMID- 9755041
TI - Mechanical advantage of the thumb muscles.
AB - The purpose of this study was to measure the moment arms of four extrinsic
muscles (flexor pollicis longus, extensor pollicis longus, extensor pollicis
brevis, and abductor pollicis longus) and four intrinsic muscles (flexor pollicis
brevis, abductor pollicis brevis, adductor pollicis, and opponents pollicis) of
the thumb at the interphalangeal, the metacarpophalangeal, and the
carpometacarpal joints in the same cadaver specimens and to examine the specific
role of each muscle. Measurements were made on seven fresh frozen cadaver hands.
The moment arms were measured during flexion/extension of the interphalangeal
joint, flexion/extension and adduction/abduction of the metacarpophalangeal
joint, and flexion/extension and adduction/abduction of the carpometacarpal
joint. Moment arms were computed using the slope of the tendon excursion joint
angle relationship. The specific function of each muscle was determined by
multiplying the measured moment arms by the maximum force that each muscle can
generate. It was found that the flexor pollicis longus was a pure flexor while
flexor pollicis brevis was an adductor as well as a flexor, the extensor pollicis
longus was an extensor and an adductor, extensor pollicis brevis was an extensor
and a mild abductor, the abductor pollicis longus was an extensor as well as an
abductor, the abductor pollicis brevis was mainly an abductor, the adductor
pollicis was a major flexor as well as an adductor, and the opponents pollicis
was a flexor and an abductor.
PMID- 9755042
TI - A high-accuracy three-dimensional coordinate digitizing system for reconstructing
the geometry of diarthrodial joints.
AB - This paper describes the design and performance evaluation of a three-dimensional
(3-D) coordinate digitizing system (3-DCDS) for measuring both soft and hard
biological tissue. The system incorporates a visible semiconducting laser beam
and an X-Y positioning table to directly measure 3-D coordinates that define
surface points. Experiments conducted to evaluate the performance of the system
showed that it delivers an accuracy of 0.1 microm in the Z-direction and 1.4
microm in the X-Y plane, and an overall system root-mean-squared error (RMSE) of
8 microm on surfaces with slopes of less than 45 degrees . This error is lower
than that of previously reported measurement techniques. The 3-DCDS measures 3-D
coordinates of surface points uniformly separated by 500 microm in the X-Y plane.
Because the 3-DCDS is automated, the coordinates are measured efficiently and the
accuracy is independent of operator skill. These highly accurate coordinates can
be easily incorporated into nodal values for 3-D finite element models (FEM) of
diarthrodial joints. To show the use of the 3-DCDS, the 3-D surface coordinates
of human menisci were measured from a cadaver specimen.
PMID- 9755043
TI - Focus on "exocytosis is not involved in activation of Cl- secretion via CFTR in
Calu-3 airway epithelial cells".
PMID- 9755044
TI - Exocytosis is not involved in activation of Cl- secretion via CFTR in Calu-3
airway epithelial cells.
AB - Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane
conductance regulator (CFTR) Cl- channel, which mediates transepithelial Cl-
transport in a variety of epithelia, including airway, intestine, pancreas, and
sweat duct. In some but not all epithelial cells, cAMP stimulates Cl- secretion
in part by increasing the number of CFTR Cl- channels in the apical plasma
membrane. Because the mechanism whereby cAMP stimulates CFTR Cl- secretion is
cell-type specific, our goal was to determine whether cAMP elevates CFTR-mediated
Cl- secretion across serous airway epithelial cells by stimulating the insertion
of CFTR Cl- channels from an intracellular pool into the apical plasma membrane.
To this end we studied Calu-3 cells, a human airway cell line with a serous cell
phenotype. Serous cells in human airways, such as Calu-3 cells, express high
levels of CFTR, secrete antibiotic-rich fluid, and play a critical role in airway
function. Moreover, dysregulation of CFTR-mediated Cl- secretion in serous cells
is thought to contribute to the pathophysiology of cystic fibrosis lung disease.
We report that cAMP activation of CFTR-mediated Cl- secretion across human serous
cells involves stimulation of CFTR channels present in the apical plasma membrane
and does not involve the recruitment of CFTR from an intracellular pool to the
apical plasma membrane.
PMID- 9755045
TI - Collagen gel overlay induces apoptosis of polarized cells in cultures:
disoriented cell death.
AB - In this study, we attempted to investigate the response of polarized cells to
inappropriate interaction with the extracellular matrix. Cell lines of epithelial
[Madin-Darby canine kidney (MDCK) and LLC-PK1], endothelial [bovine aortic
endothelial cells (BAEC)], and mesenchymal (ESK-4 and NIH/3T3) origins were
employed. With collagen gel overlay, MDCK cells underwent membrane remodeling and
gradually developed lumen formation within 24 h. Apoptosis could also be observed
following cell remodeling. The ratio of apoptosis was enhanced from 12.1 +/- 2.4%
within 24 h to 58.4 +/- 9.8% at day 3, and finally the monolayer was
disintegrated. Collagen gel overlay-induced apoptosis was not a result of
physical stress, since agarose gel overlay did not induce any morphological
alterations. All epithelial and endothelial cells examined developed apoptosis in
response to collagen overlay. In contrast, collagen overlay did not affect growth
of fibroblasts at all, although their growth under agarose gel was slightly
hindered due to physical stress. Collagen overlay-induced apoptosis seems to be a
unique phenomenon for polarized cells and thus is defined as "disoriented cell
death." Furthermore, anti-alpha2-integrin antibody could abolish collagen overlay
induced morphological changes and apoptosis in MDCK cells, indicating that
signals through alpha2-integrin on the apical membrane are required for
disoriented cell death. Finally, Bcl-2 overexpression prolonged survival of MDCK
cells in response to collagen overlay, but these cells eventually developed
apoptosis due to downregulation of Bcl-2 protein. These findings indicate that
inappropriate cell-matrix interaction results in apoptosis, which may account for
cell death mechanisms during developmental processes or under pathological
conditions.
PMID- 9755046
TI - Monocyte/macrophages evoke epithelial dysfunction: indirect role of tumor
necrosis factor-alpha.
AB - We examined the ability of monocytes (MPhi) activated by bacterial products to
alter epithelial physiology. Confluent monolayers of the T84 colonic epithelial
cell line were grown on filter supports and then cocultured in the presence of
human MPhi with or without the activating agents bacterial lipopolysaccharide and
the bacterial tripeptide formyl-methionyl-leucyl-phenylalanine. After 24 or 48 h,
monolayers were mounted in Ussing chambers where parameters of epithelial
function were measured. Exposure to activated MPhi resulted in a significant
increase (P < 0.05) in baseline short-circuit current (250% after 48 h) that was
associated with enhanced secretion of Cl-. In addition, epithelial permeability
was significantly increased as shown by reduced transepithelial resistance and
increased flux of 51Cr-EDTA. Activated MPhi produced substantial amounts
(approximately 3 ng/ml at 48 h) of tumor necrosis factor-alpha (TNF-alpha). TNF
alpha was identified as a key mediator acting via an autocrine mechanism to
induce epithelial pathophysiology. Our data show that MPhi, when activated by
common bacterial components, are potent effector cells capable of initiating
significant changes in the transport and barrier properties of a model
epithelium.
PMID- 9755048
TI - In vivo and in vitro induction of c-fos in avian exocrine salt gland cells.
AB - Osmotic stress in ducklings (Anas platyrhynchos) results in salt secretion and
adaptive cell proliferation and differentiation in the nasal glands. We
investigated whether osmotic stress in vivo or muscarinic ACh receptor activation
in vitro changed the expression levels of the cellular protooncogene products Fos
and Jun, which may play a role in the initiation of the adaptive processes. Using
Fos- and Jun-specific polyclonal antisera in Western blot experiments, we
demonstrated that Jun is constitutively expressed in nasal gland tissue, whereas
Fos is not detectable in tissue from unstressed (naive) animals. Under conditions
of osmotic stress imposed by replacing the drinking water of the animals with a
1% NaCl solution, Jun protein remains constant in nasal gland tissue, whereas Fos
protein is transiently upregulated. Treatment of cultured nasal gland tissue with
muscarinic agonists results in a transcriptionally regulated expression of Fos in
an atropine-sensitive manner. Immunohistochemical experiments show that Fos
accumulation occurs in the nuclei of the secretory cells. These results indicate
that the activation of the c-fos gene induced by muscarinic ACh receptor-mediated
signaling pathways may play an important role in the initiation of adaptive
growth and differentiation processes in nasal glands of osmotically stressed
ducklings.
PMID- 9755047
TI - Functional and molecular identification of a novel chloride conductance in canine
colonic smooth muscle.
AB - Swelling-activated or volume-sensitive Cl- currents are found in numerous cell
types and play a variety of roles in their function; however, molecular
characterization of the channels is generally lacking. Recently, the molecular
entity responsible for swelling-activated Cl- current in cardiac myocytes has
been identified as ClC-3. The goal of our study was to determine whether such a
channel exists in smooth muscle cells of the canine colon using both molecular
biological and electrophysiological techniques and, if present, to characterize
its functional and molecular properties. We hypothesized that ClC-3 is present in
colonic smooth muscle and is regulated in a manner similar to the molecular
entity cloned from heart. Indeed, the ClC-3 gene was expressed in colonic
myocytes, as demonstrated by reverse transcriptase polymerase chain reaction
performed on isolated cells. The current activated by decreasing extracellular
osmolarity from 300 to 250 mosM was outwardly rectifying and dependent on the Cl-
gradient. Current magnitude increased and reversed at more negative potentials
when Cl- was replaced by I- or Br-. Tamoxifen ([Z]-1-[p-dimethylaminoethoxy
phenyl]-1,2-diphenyl-1-butene; 10 microM) and DIDS (100 microM) inhibited the
current, whereas 25 microM niflumic acid, 10 microM nicardipine, and Ca2+ removal
had no effect. Current was inhibited by 1 mM extracellular ATP in a voltage
dependent manner. Cl- current was also regulated by protein kinase C, as phorbol
12,13-dibutyrate (300 nM) decreased Cl- current magnitude, while chelerythrine
chloride (30 microM) activated it under isotonic conditions. Our findings
indicate that a current activated by hypotonic solution is present in colonic
myocytes and is likely mediated by ClC-3. Furthermore, we suggest that the ClC-3
may be an important mechanism controlling depolarization and contraction of
colonic smooth muscle under conditions that impose physical stress on the cells.
PMID- 9755049
TI - Cystic fibrosis transmembrane conductance regulator activation by cAMP
independent mechanisms.
AB - Recent studies have demonstrated that several compounds with diverse structures
can activate wild-type cystic fibrosis transmembrane conductance regulator (CFTR)
by non-receptor-mediated mechanisms. Some of these compounds have been shown to
enhance cAMP-dependent activation of DeltaF508-CFTR. This study was undertaken to
compare the mechanisms by which genistein, IBMX, milrinone, 8-cyclopentyl-1, 3
dipropylxanthine (CPX), the benzimidazolone NS004, and calyculin A increase CFTR
activity. Our studies demonstrate that, in transfected NIH-3T3 cells, maximal
enhancements of forskolin-dependent DeltaF508-CFTR activity are greatest with
genistein, IBMX, and NS004. Milrinone, genistein, CPX, NS004, and calyculin A do
not increase cellular cAMP. Because forskolin and calyculin A increase in vivo
phosphorylation of cAMP binding response element (CREB), the inability of
milrinone, genistein, CPX, and NS004 to increase CREB phosphorylation suggests
that they do not stimulate protein kinase A or inhibit phosphatase activity. Our
data suggest that the mechanisms by which genistein and NS004 activate CFTR
differ. We also demonstrate that, in NIH-3T3 cells, IBMX-dependent enhancement of
cAMP-dependent CFTR activity is not due to an increase in cellular cAMP and may
involve a mechanism like that of genistein.
PMID- 9755050
TI - Electrophysiological characteristics of the proton-coupled peptide transporter
PEPT2 cloned from rat brain.
AB - We have cloned a peptide transporter from rat brain and found it to be identical
to rat kidney PEPT2. In the present study we characterize the transport function
of the rat brain PEPT2, with special emphasis on electrophysiological properties
and interaction with N-acetyl-L-aspartyl-L-glutamate (NAAG). When heterologously
expressed in HeLa cells and in SK-N-SH cells, PEPT2 transports several dipeptides
but not free amino acids in the presence of a proton gradient. NAAG competes with
other peptides for the PEPT2-mediated transport process. When PEPT2 is expressed
in Xenopus laevis oocytes, substrate-induced inward currents are detectable with
dipeptides of differing charge in the presence of a proton gradient. Proton
activation kinetics are similar for differently charged peptides. NAAG is a
transportable substrate for PEPT2, as evidenced by NAAG-induced currents. The
Hill coefficient for protons for the activation of the transport of differently
charged peptides, including NAAG, is 1. Although the peptide-to-proton
stoichiometry for negatively charged peptides is 1, the transport nonetheless is
associated with transfer of positive charge into the oocyte, as indicated by
peptide-induced inward currents.
PMID- 9755051
TI - Expression of myosin isoforms in smooth muscle cells in the corpus cavernosum
penis.
AB - Corpus cavernosum smooth muscle (CCSM) in the penis is unique in that it exhibits
a high resting tone and, on stimulation, the muscle cells relax, allowing
cavernous spaces to fill with blood, which results in an erection (tumescence).
During detumescence, the muscle cells contract and return to the state of high
resting tone. This study was undertaken to determine whether CCSM with these
unique properties contains myosin isoforms typical of aorta or bladder smooth
muscles, muscles that exhibit tonic and phasic characteristics, respectively. RT
PCR revealed that normal CCSM contains an SM2/SM1 mRNA ratio of 1.2:1 (similar to
the rabbit aorta). Approximately 31% of the myosin heavy chain transcripts
possess a 21-nt insert (predominant in bladder smooth muscle but not expressed in
aorta) that encodes the seven-amino acid insert near the NH2-terminal ATP binding
region in the head portion of the myosin molecule found in SMB, with the
remaining mRNA being noninserted (SMA). Quantitative competitive RT-PCR revealed
that the CCSM possesses approximately 4.5-fold less SMB than the bladder smooth
muscle. Western blot analysis using an antibody specific for the seven-amino acid
insert reveals that both SM1 and SM2 in the CCSM contain the seven-amino acid
insert. Furthermore, SMB containing the seven-amino acid insert was localized in
the CCSM by immunofluorescence microscopy using this highly specific antibody.
The analysis of the expression of LC17 isoforms a and b in the CCSM revealed that
it is similar to that of bladder smooth muscle. Thus the CCSM possesses an
overall myosin isoform composition intermediate between aorta and bladder smooth
muscles, which generally express tonic- and phasiclike characteristics,
respectively. Two-dimensional gel electrophoresis showed a relatively low level
(approximately 10%) of Ca2+-dependent light-chain (LC20) phosphorylation at the
basal tone, which reaches approximately 23% in response to maximal stimulation.
The presence of noninserted and inserted myosin isoforms with low and high levels
of actin-activated ATPase activities, respectively, in the CCSM may contribute to
the ability of the CCSM to remain in a state of high resting tone and to relax
rapidly for normal penile function.
PMID- 9755052
TI - Cytokine-mediated PGE2 expression in human colonic fibroblasts.
AB - We investigated prostanoid biogenesis in human colonic fibroblasts (CCD-18Co and
5 primary fibroblast cultures) and epithelial cell lines (NCM460, T84, HT-29, and
LS 174T) and the effect of PGE2 on fibroblast morphology. Cytokine-stimulated
PGE2 production was measured. PGH synthase-1 and -2 (PGHS-1 and -2) protein and
mRNA expression were evaluated. Basal PGE2 levels were low in all cell types
(0.15-6.47 ng/mg protein). Treatment for 24 h with interleukin-1beta (IL-1beta;
10 ng/ml) or tumor necrosis factor-alpha (50 ng/ml), respectively, elicited
maximal 25- and 6-fold inductions of PGE2 synthesis in CCD-18Co cultures and
similar results in primary fibroblast cultures; maximal inductions with IL-1beta
in colonic epithelial cell lines were from zero to fivefold. Treatment of CCD
18Co fibroblasts with IL-1beta caused maximal 21- and 53-fold increases,
respectively, in PGHS-2 protein and mRNA levels without altering PGHS-1
expression. PGE2 (0.1 micromol/l) elicited a dramatic shape change in selected
fibroblasts. Colonic fibroblasts are potentially important as cytokine targets
and a source of and target for colonic prostanoids in vivo.
PMID- 9755053
TI - Characterization of two Mg2+ transporters in sealed plasma membrane vesicles from
rat liver.
AB - The plasma membrane of mammalian cells possesses rapid Mg2+ transport mechanisms.
The identity of Mg2+ transporters is unknown, and so are their properties. In
this study, Mg2+ transporters were characterized using a biochemically and
morphologically standardized preparation of sealed rat liver plasma membranes
(LPM) whose intravesicular content could be set and controlled. The system has
the advantages that it is not regulated by intracellular signaling machinery and
that the intravesicular ion milieu can be designed. The results indicate that 1)
LPM retain trapped intravesicular total Mg2+ with negligible leak; 2) the
addition of Na+ or Ca2+ induces a concentration- and temperature-dependent efflux
corresponding to 30-50% of the intravesicular Mg2+; 3) the rate of flux is very
rapid (137.6 and 86.8 nmol total Mg2+ . micrometer -2 . min-1 after Na+ and Ca2+
addition, respectively); 4) coaddition of maximal concentrations of Na+ and Ca2+
induces an additive Mg2+ efflux; 5) both Na+- and Ca2+-stimulated Mg2+ effluxes
are inhibited by amiloride, imipramine, or quinidine but not by vanadate or Ca2+
channel blockers; 6) extracellular Na+ or Ca2+ can stimulate Mg2+ efflux in the
absence of Mg2+ gradients; and 7) Mg2+ uptake occurs in LPM loaded with Na+ but
not with Ca2+, thus indicating that Na+/Mg2+ but not Ca2+/Mg2+ exchange is
reversible. These data are consistent with the operation of two distinct Mg2+
transport mechanisms and provide new information on rates of Mg2+ transport,
specificity of the cotransported ions, and reversibility of the transport.
PMID- 9755054
TI - Gating kinetics of Shaker K+ channels are differentially modified by general
anesthetics.
AB - The ShakerB K+ channel was used as a model voltage-gated channel to probe the
interaction of volatile general anesthetics with gating mechanisms. The effects
of three anesthetics, chloroform (CHCl3), isoflurane, and halothane, were studied
using recombinant native and mutant Shaker channels expressed in Xenopus oocytes.
Gating currents and macroscopic ionic currents were recorded with the cut-open
oocyte voltage-clamp technique. The effects of CHCl3 and isoflurane on gating
kinetics of noninactivating mutants were opposite, whereas halothane had no
effect. The effects on ionic currents were also agent dependent: CHCl3 and
halothane produced a reduction of the macroscopic conductance, whereas isoflurane
increased it. The results indicate that the gating machinery of the channel is
mostly insensitive to the anesthetics during activation until near the open
state. The effects on the conductance are mainly due to changes in the
transitions in and out of the open state. The data give support to direct protein
anesthetic interactions. The magnitude and nature of the effects invite
reconsideration of Shaker-like K+ channels as important sites of action of
general anesthetics.
PMID- 9755055
TI - Energy-dependent redox state of heme a + a3 and copper of cytochrome oxidase in
perfused rat brain in situ.
AB - Using the blood-free perfused rat brain, we examined the redox behavior of
cytochrome oxidase of two chromophores, heme a + a3 and copper. When perfusate
inflow was stopped to induce global ischemia, the reduction of heme a + a3 was
triphasic, with a rapid phase, a slow phase, and a second rapid phase. In
contrast, the reduction of copper was monophasic after the rapid phase of heme a
+ a3. The triphasic reduction of heme a + a3 was diminished by energy-depleting
treatments, such as addition of an uncoupler. The time course of the reduction of
copper was not affected by the energy depletion. During global ischemia the
decrease in creatine phosphate nearly paralleled the reduction of heme a + a3,
whereas ATP remained at the control level until approximately 60% of heme a + a3
was reduced in the rapid phase. In the slow phase, ATP started to decrease with
the reduction of copper. The redox behavior of copper was similar to the slow
phase of the reduction of heme a + a3 because of the higher oxygen affinity of
copper than of heme a + a3. Therefore, the rapid phase of the reduction of heme a
+ a3 can be used as an alarm before a decrease in ATP, whereas the reduction of
copper indicates a decrease in ATP under severe hypoxia. Thus the copper signal
in noninvasive near-infrared spectroscopy is a useful parameter for the clinical
setting.
PMID- 9755056
TI - Ascorbate and glutathione homeostasis in vascular smooth muscle cells:
cooperation with endothelial cells.
AB - Human umbilical vein smooth muscle cells (HUVSMCs) utilize extracellular cystine,
glutathione (GSH), and N-acetylcysteine (NAC) to synthesize cellular GSH.
Extracellular cystine was effective from 5 microM, whereas GSH and NAC were
required at 100 microM for comparable effects. The efficacy of extracellular GSH
was dependent on de novo GSH synthesis, indicating a dependence on cellular gamma
glutamyltransferase (glutamyl transpeptidase). Coculture of syngenetic HUVSMCs
and corresponding human umbilical vein endothelial cells (HUVECs) on porous
supports restricted cystine- or GSH-stimulated synthesis of HUVSMC GSH when
supplied on the "luminal" endothelial side. Thus HUVSMC GSH rapidly attained a
steady-state level below that achieved in the absence of interposed HUVECs.
HUVSMCs also readily utilize both reduced ascorbate (AA) and oxidized
dehydroascorbate (DHAA) over the range 50-500 microM. Phloretin effectively
blocked both AA- and DHAA-stimulated assimilation of intracellular AA, indicating
a role for a glucose transporter in their transport. Uptake of extracellular AA
was also sensitive to extracellular, but not intracellular, thiol depletion. When
AA was applied to the endothelial side of the coculture model, assimilation of
intracellular AA in HUVSMCs was restricted to a steady-state level below that
achieved by free access.
PMID- 9755057
TI - Cytosolic pH regulates GCl through control of phosphorylation states of CFTR.
AB - Our objective in this study was to determine the effect of changes in luminal and
cytoplasmic pH on cystic fibrosis transmembrane regulator (CFTR) Cl- conductance
(GCl). We monitored CFTR GCl in the apical membranes of sweat ducts as reflected
by Cl- diffusion potentials (VCl) and transepithelial conductance (GCl). We found
that luminal pH (5.0-8.5) had little effect on the cAMP/ATP-activated CFTR GCl,
showing that CFTR GCl is maintained over a broad range of extracellular pH in
which it functions physiologically. However, we found that phosphorylation
activation of CFTR GCl is sensitive to intracellular pH. That is, in the presence
of cAMP and ATP [adenosine 5'-O-(3-thiotriphosphate)], CFTR could be
phosphorylated at physiological pH (6.8) but not at low pH (approximately 5.5).
On the other hand, basic pH prevented endogenous phosphatase(s) from
dephosphorylating CFTR. After phosphorylation of CFTR with cAMP and ATP, CFTR GCl
is normally deactivated within 1 min after cAMP is removed, even in the presence
of 5 mM ATP. This deactivation was due to an increase in endogenous phosphatase
activity relative to kinase activity, since it was reversed by the reapplication
of ATP and cAMP. However, increasing cytoplasmic pH significantly delayed the
deactivation of CFTR GCl in a dose-dependent manner, indicating inhibition of
dephosphorylation. We conclude that CFTR GCl may be regulated via shifts in
cytoplasmic pH that mediate reciprocal control of endogenous kinase and
phosphatase activities. Luminal pH probably has little direct effect on these
mechanisms. This regulation of CFTR may be important in shifting electrolyte
transport in the duct from conductive to nonconductive modes.
PMID- 9755058
TI - Cl- transport in an immortalized human epithelial cell line (NCM460) derived from
the normal transverse colon.
AB - Cells of a newly described, immortalized, epithelial, human transverse colonic
cell line, NCM460, reach approximately 90% confluence on plastic and develop
transepithelial resistances of 120-250 Omega . cm2 on porous substrates. Its
utility as a model for the transverse human colon was validated by comparing
second messenger-mediated Cl- transport, using the fluorescent probe 6-methoxy
quinolyl acetoethyl ester, in NCM460 cells and colonocytes isolated from human
transverse crypts. Basal Cl- influx was increased (P < 0.01) by PGE1 (1 microM),
forskolin (1 microM), 8-bromoadenosine 3'5'-cyclic monophosphate (100 microM),
heat-stable Escherichia coli enterotoxin (STa; 1 microM), 8-bromoguanosine 3'5'
cyclic monophosphate (100 microM), histamine (1 microM), and phorbol 12,13
dibutyrate (1 microM) in both cell types. The Cl- channel blocker diphenylamine 2
carboxylic acid (50 microM) and the Na+-K+-2Cl- cotransport inhibitor furosemide
(1 microM), but not the K+ channel blocker Ba2+ (3 mM), inhibited these Cl-
permeabilities. These cells possess transcripts for cystic fibrosis transmembrane
conductance regulator, Na+-K+-2Cl- cotransporter, STa receptor, and intestine
specific cGMP-dependent protein kinase II. Thus cAMP-, cGMP-, and Ca2+-dependent
secretagogues act on NCM460 and primary colonocytes to stimulate Cl- transport.
This validates the utility of NCM460 as a model for transverse colonic crypts and
is the first demonstration of a colonic cell line whose origin is known.
PMID- 9755059
TI - NF-kappaB inactivation converts a hepatocyte cell line TNF-alpha response from
proliferation to apoptosis.
AB - Toxins convert the hepatocellular response to tumor necrosis factor-alpha (TNF
alpha) stimulation from proliferation to cell death, suggesting that hepatotoxins
somehow sensitize hepatocytes to TNF-alpha toxicity. Because nuclear factor
kappaB (NF-kappaB) activation confers resistance to TNF-alpha cytotoxicity in
nonhepatic cells, the possibility that toxin-induced sensitization to TNF-alpha
killing results from inhibition of NF-kappaB-dependent gene expression was
examined in the RALA rat hepatocyte cell line sensitized to TNF-alpha
cytotoxicity by actinomycin D (ActD). ActD did not affect TNF-alpha-induced
hepatocyte NF-kappaB activation but decreased NF-kappaB-dependent gene
expression. Expression of an IkappaB superrepressor rendered RALA hepatocytes
sensitive to TNF-alpha-induced apoptosis in the absence of ActD. Apoptosis was
blocked by caspase inhibitors, and TNF-alpha treatment led to activation of
caspase-2, caspase-3, and caspase-8 only when NF-kappaB activation was blocked.
Although apoptosis was blocked by the NF-kappaB-dependent factor nitric oxide
(NO), inhibition of endogenous NO production did not sensitize cells to TNF-alpha
induced cytotoxicity. Thus NF-kappaB activation is the critical intracellular
signal that determines whether TNF-alpha stimulates hepatocyte proliferation or
apoptosis. Although exogenous NO blocks RALA hepatocyte TNF-alpha cytotoxicity,
endogenous production of NO is not the mechanism by which NF-kappaB activation
inhibits this death pathway.
PMID- 9755060
TI - Modeling cell volume regulation in nonexcitable cells: the roles of the Na+ pump
and of cotransport systems.
AB - The purpose of this study is to contribute to understanding the role of Na+-K+
ATPase and of ionic cotransporters in the regulation of cell volume, by employing
a model that describes the rates of change of the intracellular concentrations of
Na+, K+, and Cl-, of the cell volume, and of the membrane potential. In most
previous models of dynamic cellular phenomena, Na+-K+-ATPase is incorporated via
phenomenological formulations; the enzyme is incorporated here via an explicit
kinetic scheme. Another feature of the present model is the capability to perform
short-term cell volume regulation mediated by cotransporters of KCl and NaCl. The
model is employed to perform numerical simulations for a "typical" nonpolarized
animal cell. Basically, the results are consistent with the view that the Na+
pump mainly plays a long-term role in the maintenance of the electrochemical
gradients of Na+ and K+ and that short-term cell volume regulation is achieved
via passive transport, exemplified in this case by the cotransport of KCl and
NaCl.
PMID- 9755062
TI - Heme oxygenase-1 induction in skeletal muscle cells: hemin and sodium
nitroprusside are regulators in vitro.
AB - The heat shock protein heme oxygenase-1 (HO-1) is regulated by a variety of
physiological and pharmacological factors. In skeletal muscle tissue, HO-1 has
been shown to be induced only by exercise and electrical stimulation in vivo.
Both hemin and sodium nitroprusside (SNP) are potent inducers of HO-1 in other
tissues. In this study, we examined the effects of these two agents on HO-1
induction in L6.G8 rat skeletal myoblast cells. Hemin and SNP increased cellular
heme oxygenase activity in both a time- and concentration-dependent manner.
Increases in the HO-1 mRNA level and protein expression accompanied changes in
heme oxygenase activity. The ability of SNP to induce HO-1 in L6.G8 cells was
reduced by coincubation with hydroxocobalamin, a known nitric oxide (NO)
scavenger, suggesting that NO itself may be involved in HO-1 gene stimulation.
These results indicate that HO-1 expression is sensitive to both hemin and SNP in
skeletal myoblast cells and may indicate an important regulatory mechanism of
heme catabolism in skeletal muscle tissue.
PMID- 9755061
TI - A role for MAP kinase in differentiated smooth muscle contraction evoked by alpha
adrenoceptor stimulation.
AB - The purpose of this study was to investigate the potential role of mitogen
activated protein (MAP) kinase in smooth muscle contraction by monitoring MAP
kinase activation, caldesmon phosphorylation, and contractile force during
agonist stimulation. Isometric tension in response to KCl and phenylephrine (PE)
was measured from strips of ferret aorta. MAP kinase activation was monitored by
Western blot using a phosphospecific p44/p42 MAP kinase antibody. Caldesmon
phosphorylation was assessed using specific phosphocaldesmon antibodies. We
report here that treatment of smooth muscle strips with PD-098059, a specific
inhibitor of MAP kinase kinase, did not detectably modify the KCl-evoked
contraction but significantly inhibited the contraction to PE in the absence of
extracellular Ca2+. In this experimental condition, where the contraction occurs
in the absence of increases in 20-kDa myosin light chain phosphorylation, PD
098059 also inhibited significantly MAP kinase and caldesmon phosphorylation.
Collectively, these results demonstrate a direct cause-and-effect relationship
between MAP kinase activation and Ca2+-independent smooth muscle contraction and
support the concept of caldesmon phosphorylation as the missing link between both
events.
PMID- 9755063
TI - Minor role of a Ca2+-depleted sarcoplasmic reticulum in heterologous
desensitization of smooth muscle to K+.
AB - Exposure of porcine carotid artery smooth muscle (PCASM) to histamine was
followed by a large reduction in the rate of force generation in response to 40
mM KCl. This was shown to be a manifestation of slow attainment of a steady-state
myoplasmic Ca2+ concentration ([Ca2+]i). We hypothesized that if net
transsarcolemmal Ca2+ flux into the depolarized PCASM cells is the same before
and after a desensitizing histamine treatment, then the transient attenuation of
the increase in [Ca2+]i may be due to accelerated uptake of Ca2+ by a partially
depleted sarcoplasmic reticulum (SR) acting as a Ca2+ sink or superficial buffer
barrier. We tested this hypothesis by eliciting responses of "desensitized PCASM"
to 40 mM KCl in the presence of cyclopiazonic acid (CPA), an SR Ca2+-ATPase
inhibitor. Contractions of CPA-treated tissues were attenuated less than those of
tissues not treated with CPA, but they were not abolished. CPA-insensitive
mechanism(s) dominated the desensitization. We conclude that histamine
pretreatment reduced net transsarcolemmal Ca2+ flux into PCASM in response to 40
mM KCl.
PMID- 9755064
TI - Hypotonicity activates transcription through ERK-dependent and -independent
pathways in renal cells.
AB - Acute hypotonic shock (50% dilution of medium with sterile water, but not with
isotonic NaCl) activated the extracellular signal response kinase (ERK) mitogen
activated protein (MAP) kinases in renal medullary cells, as measured by Western
analysis with a phospho-ERK-specific antibody and by in vitro kinase assay of
epitope-tagged ERKs immunoprecipitated from stable HA-ERK transfectants.
Hypotonicity also activated the transcription factor and ERK substrate Elk-1 in a
partially PD-98059-sensitive fashion, as assessed by chimeric reporter gene
assay. Consistent with these data, hypotonic stress activated transcription of
the immediate-early gene transcription factor Egr-1 in a partially PD-98059
sensitive fashion. Hypotonicity-inducible Egr-1 transcription was mediated in
part through 5'-flanking regions containing serum response elements and in part
through the minimal Egr-1 promoter. Elimination of the Ets motifs adjacent to key
regulatory serum response elements in the Egr-1 promoter diminished the effect of
hypotonicity but failed to abolish it. Interestingly, hypotonicity also
transiently activated p38 and c-Jun NH2-terminal kinase 1, as determined by
immunoblotting with anti-phospho-MAP kinase antibodies. Taken together, these
data strongly suggest that hypotonicity activates immediate-early gene
transcription in renal medullary cells via MAP kinase kinase-dependent and
independent mechanisms.
PMID- 9755065
TI - Identification of the pH sensor and activation by chemical modification of the
ClC-2G Cl- channel.
AB - Rabbit and human ClC-2G Cl- channels are voltage sensitive and activated by
protein kinase A and low extracellular pH. The objective of the present study was
to investigate the mechanism involved in acid activation of the ClC-2G Cl-
channel and to determine which amino acid residues play a role in this acid
activation. Channel open probability (Po) at +/-80 mV holding potentials
increased fourfold in a concentration-dependent manner with extracellular H+
concentration (that is, extracellular pH, pHtrans), with an apparent acidic
dissociation constant of pH 4.95 +/- 0.27. 1-Ethyl-3(3
dimethylaminopropyl)carbodiimide-catalyzed amidation of the channel with glycine
methyl ester increased Po threefold at pHtrans 7.4, at which the channel normally
exhibits low Po. With extracellular pH reduction (protonation) or amidation,
increased Po was due to a significant increase in open time constants and a
significant decrease in closed time constants of the channel gating, and this
effect was insensitive to applied voltage. With the use of site-directed
mutagenesis, the extracellular region EELE (amino acids 416-419) was identified
as the pH sensor and amino acid Glu-419 was found to play the key or predominant
role in activation of the ClC-2G Cl- channel by extracellular acid.
PMID- 9755066
TI - Early changes in muscle fiber size and gene expression in response to spinal cord
transection and exercise.
AB - Muscles of spinal cord-transected rats exhibit severe atrophy and a shift toward
a faster phenotype. Exercise can partially prevent these changes. The goal of
this study was to investigate early events involved in regulating the muscle
response to spinal transection and passive hindlimb exercise. Adult female
Sprague-Dawley rats were anesthetized, and a complete spinal cord transection
lesion (T10) was created in all rats except controls. Rats were killed 5 or 10
days after transection or they were exercised daily on motor-driven bicycles
starting at 5 days after transection and were killed 0.5, 1, or 5 days after the
first bout of exercise. Structural and biochemical features of soleus and
extensor digitorum longus (EDL) muscles were studied. Atrophy was decreased in
all fiber types of soleus and in type 2a and type 2x fibers of EDL after 5 days
of exercise. However, exercise did not appear to affect fiber type that was
altered within 5 days of spinal cord transection: fibers expressing myosin heavy
chain 2x increased in soleus and EDL, and extensive coexpression of myosin heavy
chain in soleus was apparent. Activation of satellite cells was observed in both
muscles of transected rats regardless of exercise status, evidenced by increased
accumulation of MyoD and myogenin. Increased expression was transient, except for
MyoD, which remained elevated in soleus. MyoD and myogenin were detected both in
myofiber and in satellite cell nuclei in both muscles, but in soleus, MyoD was
preferentially expressed in satellite cell nuclei, and in EDL, MyoD was more
readily detectable in myofiber nuclei, suggesting that MyoD and myogenin have
different functions in different muscles. Exercise did not affect the level or
localization of MyoD and myogenin expression. Similarly, Id-1 expression was
transiently increased in soleus and EDL upon spinal cord transection, and no
effect of exercise was observed. These results indicate that passive exercise can
ameliorate muscle atrophy after spinal cord transection and that satellite cell
activation may play a role in muscle plasticity in response to spinal cord
transection and exercise. Finally, the mechanisms underlying maintenance of
muscle mass are likely distinct from those controlling myosin heavy chain
expression.
PMID- 9755068
TI - Increased NHE2 expression in rat intestinal epithelium during ontogeny is
transcriptionally mediated.
AB - We have previously described changes in intestinal brush-border membrane vesicle
(BBMV) Na+/H+ exchange activity and characterized Na+/H+ exchanger (NHE3)
expression during rat ontogeny. The current studies were designed to investigate
developmental changes in NHE2 expression in rat intestine. In previous studies,
pH-dependent uptake of Na+ in jejunal BBMV utilizing HOE-694 inhibition
demonstrated that NHE2 functional protein levels were lowest in 2-wk-old rats,
higher in 3-wk-old and adult rats, and highest in 6-wk-old rats [Collins et al.
Am. J. Physiol. 273 (Cell Physiol. 42): C1937-C1946, 1997]. In the current
investigation, Northern blot analyses showed that NHE2 mRNA levels in the jejunum
were similar in 6-wk-old, adult, and 3-wk-old rats and three- to fivefold lower
in 2-wk-old rats. In situ hybridization of 2- and 6-wk-old rat intestine with
NHE2-specific probes confirmed Northern blot observations. Polyclonal antibodies
were developed against an NHE2-specific peptide from amino acids 652-661. Western
blots with NHE2 antiserum showed that the intensity of a specific 90-kDa band was
lowest in 2-wk-old animals and four- to sixfold higher in 3- and 6-wk-old and
adult animals. Immunohistochemical analysis showed specific staining of NHE2
antiserum to only the apical intestinal membrane. Furthermore, nuclear run-on
analyses showed a 1.7-fold higher NHE2 transcription rate in 6-wk-old rats than
in 2-wk-old rats. Overall, the current data suggest that increases in NHE2
expression upon weaning are mediated by increased gene transcription.
PMID- 9755067
TI - Proton secretion in the male reproductive tract: involvement of Cl--independent
HCO-3 transport.
AB - The lumen of the epididymis is the site where spermatozoa undergo their final
maturation and acquire the capacity to become motile. An acidic luminal fluid is
required for the maintenance of sperm quiescence and for the prevention of
premature activation of acrosomal enzymes during their storage in the cauda
epididymis and vas deferens. We have previously demonstrated that a vacuolar H+
ATPase [proton pump (PP)] is present in the apical pole of apical and narrow
cells in the caput epididymis and of clear cells in the corpus and cauda
epididymis and that this PP is responsible for the majority of proton secretion
in the proximal vas deferens. We now show that PP-rich cells in the vas deferens
express a high level of carbonic anhydrase type II (CAII) and that acetazolamide
markedly inhibits the rate of proton secretion by 46.2 +/- 6.1%. The rate of
acidification was independent of Cl- and was strongly inhibited by SITS under
both normal and Cl--free conditions (50.6 +/- 5.0 and 57. 5 +/- 6.0%,
respectively). In the presence of Cl-, diphenylamine-2-carboxylate (DPC) had no
effect, whereas SITS inhibited proton secretion by 63.7 +/- 11.3% when applied
together with DPC. In Cl--free solution, DPC markedly inhibited proton efflux by
45.1 +/- 7.6%, SITS produced an additional inhibition of 18.2 +/- 6.6%, and
bafilomycin had no additive effect. In conclusion, we propose that CAII plays a
major role in proton secretion by the proximal vas deferens. Acidification does
not require the presence of Cl-, but DPC-sensitive Cl- channels might contribute
to basolateral extrusion of HCO-3 under Cl--free conditions. The inhibition by
SITS observed under both normal and Cl--free conditions indicates that a Cl-/HCO
3 exchanger is not involved and that an alternative HCO-3 transporter
participates in proton secretion in the proximal vas deferens.
PMID- 9755070
TI - Loading pyranine via purinergic receptors or hypotonic stress for measurement of
cytosolic pH by imaging.
AB - Although used extensively for the measurement of intracellular pH, derivatives of
fluorescein such as 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF)
have suboptimal sensitivity and can generate toxic photoproducts. These
limitations can be overcome using the pH-sensitive fluorescent dye 8
hydroxypyrene-1,3,6-trisulfonic acid (pyranine), which has improved spectroscopic
properties. However, the use of pyranine has been limited by the difficulties
encountered in delivering this highly hydrophilic dye to the cell interior. We
describe a strategy for intracellular delivery of pyranine based on the
reversible activation of purinergic P2x7 receptors, which allow permeation of the
dye into otherwise intact cells. When loaded into J774 or RAW cells by this
method, pyranine is not only more sensitive than BCECF (the dynamic range is
approximately 7-fold greater), but is retained better and is less toxic. Pyranine
was distributed throughout the cytosol but was not detectable in endomembrane
compartments. Repeated illumination resulted in blebbing and loss of functional
responsiveness of cells loaded with BCECF, whereas comparably irradiated cells
loaded with pyranine remained healthy and responsive. Pyranine can also be loaded
into cells not expressing P2x7 receptors by brief exposure to a hypotonic
solution. The properties of cells labeled by this method are similar to those
loaded via purinergic receptors and compare favorably with those of BCECF-loaded
cells. Pyranine thus provides a useful alternative to fluorescein derivatives for
the measurement of intracellular pH, particularly when using the high excitation
intensities required for microscopic digital imaging.
PMID- 9755069
TI - Localization and expression of AQP5 in cornea, serous salivary glands, and
pulmonary epithelial cells.
AB - Aquaporin (AQP) 5 gene was recently isolated from salivary gland and identified
as a member of the AQP family. The mRNA expression and localization have been
examined in several organs. The present study was focused on elucidation of AQP5
expression and localization in the eye, salivary gland, and lung in rat. RNase
protection assay confirmed intense expression of AQP5 mRNA in these organs but
negligible expression in other organs. To examine the mRNA expression sites in
the eye, several portions were microdissected for total RNA isolation. AQP5 mRNA
was enriched in cornea but not in other portions (retina, lens, iris/ciliary
body, conjunctiva, or sclera). AQP5 was selectively localized on the surface of
corneal epithelium in the eye by immunohistochemistry and immunoelectron
microscopy using an affinity-purified anti-AQP5 antibody. AQP5 was also localized
on apical membranes of acinar cells in the lacrimal gland and on the microvilli
protruding into intracellular secretory canaliculi of the serous salivary gland.
In the lung, apical membranes of type I pulmonary epithelial cells were also
immunostained with the antibody. These findings suggest a role of AQP5 in water
transport to prevent dehydration or to secrete watery products in these tissues.
PMID- 9755071
TI - Purification of active Na+-K+-ATPase using a new ouabain-affinity column.
AB - Ouabain, a specific inhibitor of Na+-K+-ATPase, was coupled to epoxy agarose via
a 13-atom spacer to make an affinity column that specifically binds Na+-K+
ATPase. Na+-K+-ATPase from rat and dog kidney was bound to the column and was
eluted as a function of enzyme conformation, altered by adding specific
combinations of ligands. Na+-K+-ATPase from both sources bound to the column in
the presence of Na + ATP + Mg and in solutions containing 30 mM K. No binding was
observed in the presence of Na or Na + ATP. These experiments suggest that Na+-K+
ATPase binds to the column under the same conditions that it binds to untethered
ouabain. Na+-K+-ATPase already bound to the column was competitively eluted with
excess free Na + ouabain or with Na + ATP. The latter eluted active enzyme. For
comparable amounts of bound Na+-K+-ATPase, Na + ouabain and Na + ATP eluted more
rat than dog Na+-K+-ATPase, consistent with the lower affinity of the rat Na+-K+
ATPase for ouabain. The ouabain-affinity column was used to purify active Na+-K+
ATPase from rat kidney microsomes and rat adrenal glomerulosa cells. The specific
activity of the kidney enzyme was increased from approximately 2 to 15 micromol
Pi . mg-1 . min-1. Na+-K+-ATPase purified from glomerulosa cells that were
prelabeled with [32P]orthophosphate was phosphorylated on the alpha-subunit,
suggesting that these cells contain a kinase that phosphorylates Na+-K+-ATPase.
PMID- 9755072
TI - Transduction pathways involved in rapid hormone receptor regulation in the
mammary epithelium.
AB - Previous studies have shown that the envelope protein of the mouse mammary tumor
virus (MMTV) rapidly upregulates prolactin (PRL) receptors by shifting them from
internal pools to the cell surface and downregulates epidermal growth factor
(EGF) receptors by inducing their internalization and degradation. This study
shows that the effect on PRL receptors is mediated by the nitric oxide (NO)/cGMP
pathway, since it can be mimicked by an NO donor or 8-bromo-cGMP and can be
blocked by an NO synthase inhibitor. In contrast, the effect on EGF receptors is
mediated by tyrosine phosphorylation and phosphatidylinositol 3-kinase (PI3K),
since it can be blocked by either a tyrosine kinase inhibitor or by a PI3K
inhibitor. Both of these pathways can be activated by a calcium ionophore and
inhibited by calcium chelation. Therefore, it appears that the mouse mammary
tumor virus envelope protein, like other retroviral envelope proteins, initially
elevates cytoplasmic calcium, which can then stimulate both the NO/cGMP and the
tyrosine phosphorylation/PI3K pathways, leading to PRL receptor upregulation and
EGF receptor downregulation, respectively.
PMID- 9755073
TI - Insulin does not change the intracellular distribution of hexokinase in rat
heart.
AB - Preliminary evidence has suggested that hexokinase in rat heart changes its
kinetic properties in response to insulin through translocation to the outer
mitochondrial membrane. We reexamined this hypothesis in light of tracer kinetic
evidence to the contrary. Our methods were as follows. Working rat hearts were
perfused with Krebs-Henseleit buffer containing glucose (5 mmol/l) and sodium
oleate (0.4 mmol/l). Dynamic glucose uptake was measured with [2-3H]glucose and
with 2-deoxy-2-[18F]fluoroglucose (2-[18F]DG). Hexokinase activity was determined
in the cytosolic and mitochondrial fractions. Our results are as follows. Uptake
of glucose and uptake of 2-[18F]DG were parallel. Insulin (1 mU/ml) increased
glucose uptake threefold but had no effect on 2-[18F]DG uptake. The tracer-to
tracee ratio decreased significantly. The Michaelis-Menten constant of hexokinase
for 2-deoxyglucose was up to 10 times higher than for glucose. There was no
difference in maximal reaction velocity. Two-thirds of hexokinase was bound to
mitochondria. Insulin neither caused translocation nor changed Michaelis-Menten
constant or maximal reaction velocity. In conclusion, the insulin-induced changes
in the tracer-to-tracee ratio are due to a shift of the rate-limiting step for
glucose uptake from transport to phosphorylation by hexokinase. Insulin does not
affect the intracellular distribution or the kinetics of hexokinase.
PMID- 9755074
TI - Altered ATP sensitivity of ATP-dependent K+ channels in diabetic rat hearts.
AB - The effects of streptozotocin-induced diabetes (5-7 days or 7 wk) on cardiac ATP
sensitive potassium channels (KATP channels) were investigated with the use of
single-channel and action potential recordings from dissociated ventricular
myocytes isolated from control and diabetic rat hearts. In inside-out patches
from diabetic myocytes (5-7 days), the IC50 for ATP inhibition was 82 +/- 7.2
microM (mean +/- SE, n = 8), twice that in controls (43 +/- 3.6 microM, n = 12).
For 7-wk diabetic rats, the IC50 was 75 +/- 2.3 microM (n = 6). Increasing
internal ADP concentration attenuated ATP-induced inhibition in both controls and
diabetics. On reducing the internal pH from 7.4 to 6.8, both control and diabetic
myocytes showed a 1.7-fold increase in the IC50 for ATP inhibition. No
differences were observed in either intraburst kinetics or unitary conductance of
single channels from control and diabetic myocytes. In diabetic myocytes, action
potential duration at 90% repolarization (APD90) was longer and more variable
than in controls and was significantly shortened by application of the KATP
channel opener cromakalim (50 microM). Cromakalim scarcely affected APD90 in
controls. Computer simulation of the longer diabetic APD90 required a lower
background conductance during the plateau phase in addition to small, measured
changes in the delayed rectifier current, transient outward current, and ATP
sensitive K+ current (KATP current, IKATP). The simulations reproduced the
enhanced sensitivity of the diabetic APD90 to changes in IKATP. These results
have important implications for cardiac function in diabetics and their treatment
by sulfonylureas.
PMID- 9755075
TI - Increased plasma gln and Leu Ra and inappropriately low muscle protein synthesis
rate in AIDS wasting.
AB - Muscle protein wasting occurs in human immunodeficiency virus (HIV)-infected
individuals and is often the initial indication of acquired immunodeficiency
syndrome (AIDS). Little is known about the alterations in muscle protein
metabolism that occur with HIV infection. Nine subjects with AIDS wasting (CD4 <
200/mm3), chronic stable opportunistic infections (OI), and >/=10% weight loss,
fourteen HIV-infected men and one woman (CD4 > 200/mm3) without wasting or OI
(asymptomatic), and six HIV-seronegative lean men (control) received a constant
intravenous infusion of [1-13C]leucine (Leu) and [2-15N]glutamine (Gln). Plasma
Leu and Gln rate of appearance (Ra), whole body Leu turnover, disposal and
oxidation rates, and [13C]Leu incorporation rate into mixed muscle protein were
assessed. Total body muscle mass/fat-free mass was greater in controls (53%) than
in AIDS wasting (43%; P = 0.04). Fasting whole body proteolysis and synthesis
rates were increased above control in the HIV+ asymptomatic group and in the AIDS
wasting group (P = 0. 009). Whole body Leu oxidation rate was greater in the HIV+
asymptomatic group than in the control and AIDS-wasting groups (P < 0.05).
Fasting mixed muscle protein synthesis rate was increased in the asymptomatic
subjects (0.048%/h; P = 0.01) but was similar in AIDS-wasting and control
subjects (0.035 vs. 0.037%/h). Plasma Gln Ra was increased in AIDS-wasting
subjects but was similar in control and HIV+ asymptomatic subjects (P < 0.001).
These findings suggest that AIDS wasting results from 1) a preferential reduction
in muscle protein, 2) a failure to sustain an elevated rate of mixed muscle
protein synthesis while whole body protein synthesis is increased, and 3) a
significant increase in Gln release into the circulation, probably from muscle.
Several interesting explanations for the increased Gln Ra in AIDS wasting exist.
PMID- 9755076
TI - Differential regulation of skeletal muscle protein turnover by insulin and IGF-I
after bacteremia.
AB - Skeletal muscle catabolism is a characteristic metabolic response to sepsis. We
investigated the ability of physiological insulin (2 nM) or insulin-like growth
factor I (IGF-I, 10 nM) concentrations to modify protein metabolism during
incubation of epitrochlearis 2, 6, or 15 days after injection of live Escherichia
coli. On days 2 and 6 postinfection, skeletal muscle exhibited an exacerbated
negative protein balance resulting from both an inhibition in protein synthesis
(25%) and an enhanced proteolysis (90%) compared with controls. By day 15
postinfection, protein balance in infected rats was significantly improved
compared with either day 2 or 6. At this time, protein synthesis was augmented
and protein degradation was decreased in infected rats relative to day 6. Insulin
or IGF-I stimulated protein synthesis in muscles from septic and control rats in
vitro to the same extent at each time point examined. The ability of insulin or
IGF-I to limit protein degradation was severely blunted 48 h after infection. On
day 6 postinfection, the effect of insulin or IGF-I to inhibit proteolysis was
more pronounced than on day 2. Incubation with IGF-I limited proteolysis to a
greater extent than insulin on both days in infected but not control rats. By day
15, insulin diminished proteolysis to the same extent as in controls. The results
suggest that injection of bacteria causes fundamental derangements in protein
metabolism that persist for days after infection.
PMID- 9755077
TI - Influence of age, hyperglycemia, leptin, and NPY on islet blood flow in obese
hyperglycemic mice.
AB - This study aimed to elucidate possible age-related changes in islet blood
perfusion in lean and obese C57BL/6 mice. Obese mice aged 1 mo were hyperglycemic
and hyperinsulinemic and had an increased islet blood flow compared with age
matched lean mice. This augmented blood flow could be abolished by pretreatment
with leptin. The islet blood perfusion was, in contrast to this, markedly
decreased in obese 6- to 7-mo-old animals compared with age-matched lean mice.
Reversal of hyperglycemia, but not hyperinsulinemia, in these obese mice with
phlorizin normalized the islet blood flow. Spontaneous reversal of hyperglycemia,
but not hyperinsulinemia, was seen in the 12-mo-old obese mice. Islet blood
perfusion in obese mice at this age did not differ compared with lean mice. It is
suggested that the initial increase in islet blood flow in obese mice is due to
the leptin deficiency. The subsequent decrease in islet blood perfusion is
probably caused by the chronic hyperglycemia. The described islet blood flow
changes may be of importance for impairment of islet function in obese
hyperglycemic mice.
PMID- 9755078
TI - Response of skeletal muscle protein synthesis to insulin in suckling pigs
decreases with development.
AB - The elevated rate of muscle protein deposition in the neonate is largely due to
an enhanced stimulation of skeletal muscle protein synthesis by feeding. To
examine the role of insulin in this response, hyperinsulinemic-euglycemic-amino
acid clamps were performed in 7- and 26-day-old pigs. Pigs were infused with 0,
30, 100, or 1,000 ng . kg-0.66 . min-1 of insulin to mimic the plasma insulin
levels observed under fasted, fed, refed, and supraphysiological conditions,
respectively. Whole body amino acid disposal was determined from the rate of
infusion of an amino acid mixture necessary to maintain plasma essential amino
acid concentrations near their basal fasting levels. A flooding dose of L-[4
3H]phenylalanine was used to measure skeletal muscle protein synthesis. Whole
body amino acid disposal increased progressively as the insulin infusion rate
increased, and this response was greater in 7- than in 26-day-old pigs. Skeletal
muscle protein synthesis was stimulated by insulin, and this response was maximal
at a low insulin infusion rate (30 ng . kg-0.66 . min-1). The stimulation of
muscle protein synthesis by insulin was also greater in 7- than in 26- day-old
pigs. These data suggest that muscle protein synthesis is more sensitive to
insulin than whole body amino acid disposal. The results further suggest that
insulin is a central regulatory factor in the elevated rate of muscle protein
deposition and the increased response of skeletal muscle protein synthesis to
feeding in the neonate.
PMID- 9755079
TI - Dual mode of action of glucose pentaacetates on hormonal secretion from the
isolated perfused rat pancreas.
AB - Isolated perfused rat pancreases were exposed, in the presence of 10. 0 mM L
leucine, to either alpha-D-glucose pentaacetate, beta-L-glucose pentaacetate, or
unesterified D-glucose, all tested at a 1.7 mM concentration. The pentaacetate
ester of alpha-D-glucose and, to a lesser extent, that of beta-L-glucose
stimulated both insulin and somatostatin release, whereas unesterified D-glucose
failed to do so. In the case of insulin output, the two esters differed from one
another not solely by the magnitude of the secretory response but also by its
time course and reversibility. Compared with these data, the most salient
difference found in the case of somatostatin release consisted of the absence of
an early secretory peak in response to alpha-D-glucose pentaacetate
administration and the higher paired ratio between the secretory responses evoked
by the esters of glucose and by unesterified D-glucose (5.5 mM) administered at
the end of the experiments. The two esters provoked an initial and short-lived
stimulation of glucagon secretion, in sharp contrast to the immediate inhibitory
action of unesterified D-glucose. Thereafter, alpha-D-glucose pentaacetate, but
not beta-L-glucose pentaacetate, caused inhibition of glucagon release, such an
effect being reversed when the administration of the ester was halted. These
findings indicate a dual mode of action of glucose pentaacetate esters on
hormonal secretion from the endocrine pancreas. The intracellular hydrolysis of
alpha-D-glucose pentaacetate and subsequent catabolism of its hexose moiety may
contribute to the early peak-shaped insulin response to this ester, to the
persistence of a positive secretory effect in B and D cells after cessation of
its administration, and to the late inhibition of glucagon release. However, a
direct effect of the esters themselves, by some as-of-yet unidentified coupling
process, is postulated to account for the stimulation of insulin and somatostatin
release by beta-L-glucose pentaacetate and for the initial enhancement of
glucagon secretion provoked by both glucose esters.
PMID- 9755080
TI - Temporal activation of p70 S6 kinase and Akt1 by insulin: PI 3-kinase-dependent
and -independent mechanisms.
AB - Several studies have suggested that activation of p70 ribosomal S6 kinase (p70 S6
kinase) by insulin may be mediated by the phosphatidylinositol 3-kinase (PI 3
kinase)-Akt pathway. However, by temporal analysis of the activation of each
kinase in L6 muscle cells, we report that the activation of the two
serine/threonine kinases (Akt and p70 S6 kinase) can be dissociated. Insulin
stimulated p70 S6 kinase in intact cells in two phases. The first phase (5 min)
of stimulation was fully inhibited by wortmannin (IC50 = 20 nM) and LY-294002
(full inhibition at 5 microM). After this early inhibition, p70 S6 kinase was
gradually stimulated by insulin in the presence of 100 nM wortmannin. After 30
min, the stimulation was 65% of the maximum attained in the absence of
wortmannin. The IC50 of wortmannin for inhibition of this second phase was
approximately 150 nM. In contrast, activation of Akt1 by insulin was completely
inhibited by 100 nM wortmannin at all time points investigated. Inhibition of
mitogen-activated protein kinase/extracellular signal-regulated protein kinase
kinase with PD-098059 (10 microM) or treatment with the protein kinase C
inhibitor bisindolylmaleimide (10 microM) had no effect on the late phase of
insulin stimulation of p70 S6 kinase. We have previously shown that GLUT-1
protein synthesis in these cells is stimulated by insulin via the mTOR-p70 S6
kinase pathway, based on its sensitivity to rapamycin. We therefore investigated
whether the signals leading to GLUT-1 synthesis correlated with the early or late
phase of stimulation of p70 S6 kinase. GLUT-1 synthesis was not inhibited by
wortmannin (100 nM). In summary, insulin activates p70 ribosomal S6 kinase in L6
muscle cells by two mechanisms, one dependent on and one independent of the
activation of PI 3-kinase. In addition, activation of Akt1 is fully inhibited by
wortmannin, suggesting that Akt1 does not participate in the late activation of
p70 S6 kinase. Wortmannin-sensitive PI 3-kinases and Akt1 are not required for
insulin stimulation of GLUT-1 protein biosynthesis.
PMID- 9755081
TI - Smaller differences in total and regional adiposity with age in women who
regularly perform endurance exercise.
AB - Our aim was to determine if women who regularly perform endurance exercise
demonstrate age-related elevations in body mass and adiposity. Ninety-five
healthy females were studied: premenopausal (n = 28; mean +/- SE age 30 +/- 1 yr)
and postmenopausal (n = 31; 56 +/- 1 yr) endurance-trained runners and
premenopausal (n = 17; 29 +/- 1 yr) and postmenopausal (n = 19; 61 +/- 1 yr)
sedentary controls. In the runners, body mass did not differ across age, but
percent fat and fat mass were higher (P < 0.05) in the postmenopausal women. The
age-related difference in total body fat, however, was only approximately 50% as
great (P < 0.01) as that observed in the sedentary controls due in part to
smaller age-related differences in central (truncal) fat. The higher fat mass in
the postmenopausal runners was modestly (inversely) related to both exercise
volume (r = -0.44, P < 0.01) and maximal oxygen consumption (r = -0.41, P <
0.01). The present findings provide experimental support for the hypothesis that
women who regularly engage in vigorous endurance exercise may not gain body
weight, undergo only a modest increase in total body fat, and do not demonstrate
a significant elevation in central adiposity with age.
PMID- 9755082
TI - Effect of fentanyl on morphine levels in the brain in rats receiving
intracerebroventricular injection of TNF-alpha.
AB - Fentanyl citrate analgesia attenuates the excess nitrogen excretion in the urine
and glucose production induced by trauma. On the other hand,
intracerebroventricular injection of morphine stimulates excretion of stress
hormones, such as catecholamines and corticosterone. Furthermore, morphine levels
in the brain are increased during fasting and sepsis. The aims of this study were
to determine whether intracerebroventricular injection of tumor necrosis factor
alpha (TNF-alpha) elevates morphine levels in the rat brain and whether
prophylactic administration of fentanyl blocks metabolic responses induced by
intracerebroventricular injection of TNF-alpha because of a reduction of morphine
levels in the brain. Morphine levels in the brain were increased from 648 to
1,134 fmol/g at 30 min after intracerebroventricular injection of TNF-alpha (P <
0.05 vs. control). This increase was associated with an increase in stress
hormones (corticosterone: 416.1 +/- 69.1 ng/ml, P < 0.05 vs. control;
epinephrine: 3,778.3 +/- 681.3 pg/ml, P < 0.01 vs. control) and an enhancement of
proteolysis (254.2 +/- 45.7 micromol Leu . kg-1 . h-1, P < 0.01 vs. control) and
glucose production (7.5 +/- 0. 7 mg . kg-1 . min-1, P < 0.05 vs. control).
Fentanyl reduced morphine levels in the brain to 624 fmol/g (not significant vs.
control), resulting in a reduction of stress hormone levels in the plasma and
blunted metabolic responses. In conclusion, prophylactic administration of
fentanyl prevented an increase in morphine levels in the brain induced by
intracerebroventricular injection of TNF-alpha, leading to a reduction in stress
hormone levels and subsequent metabolic responses.
PMID- 9755083
TI - Mechanisms of glucose intolerance during triglyceride infusion.
AB - Lipid infusions may affect glucose tolerance by effects on glucose production or
utilization. We performed double-labeled oral glucose tolerance tests with and
without a lipid infusion in eight normal subjects. During the lipid infusion,
plasma glucose and insulin levels were higher, showing some insulin resistance.
The increased glucose level was due to a higher total glucose appearance rate,
partly reproducible by a control infusion of glycerol [saline 1,181 +/- 71 mg .
kg-1 . 330 min-1 vs. lipid 1,388 +/- 100 (P < 0.05) vs. glycerol 1,276 +/- 126
(NS)]. The tracer-determined appearance rate of exogenous glucose was higher with
lipid infusion but was probably overestimated because of higher 13C recycling
into glucose. Residual systemic glucose production was increased but was
reproducible by the glycerol infusion. Total glucose disposal was increased. This
was observed despite a lower stimulation of total glucose oxidation as measured
by indirect calorimetry, whereas oxidation of exogenous glucose was normal after
correction for the lipid-induced modification of excretion rate of 13CO2.
Accordingly, glucose nonoxidative disposal was increased. These moderate
modifications of glucose metabolism (increased appearance, increased nonoxidative
disposal, and lower total oxidation) have been reported in starvation-induced or
spontaneously impaired glucose tolerance. Further impairment, especially
decreased nonoxidative glucose disposal, seems to be required to produce non
insulin-dependent diabetes mellitus.
PMID- 9755084
TI - Effect of Ca2+ and cAMP on capacitance-measured hormone secretion in human GH
secreting adenoma cells.
AB - Membrane capacitance (Cm) was measured as an index of exocytosis in human growth
hormone-secreting adenoma cells using the perforated whole cell, patch-clamp
technique; the effects of membrane depolarization, growth hormone-releasing
hormone, and 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) were
examined. Cm was increased by membrane depolarization to potentials beyond the
threshold necessary to open voltage-gated Ca2+ channels. These voltage-dependent
changes in Cm varied as a function of both depolarization amplitude and duration
and were blocked in the presence of the Ca2+ channel antagonist nitrendipine (10(
6) M). When membrane potential was clamped at the holding potential (-78 mV),
voltage-gated Ca2+ channels were closed, and neither application of growth
hormone-releasing hormone nor 8-BrcAMP affected Cm. However, when these agents
were applied to depolarized cells, where the voltage-gated Ca2+ channels were
open, the increases in Cm were augmented. From these data, it was concluded that
elevation of intracellular cAMP, per se, did not stimulate exocytosis. Rather,
Ca2+ influx through voltage-gated channels was a prerequisite for cAMP-induced
exocytosis.
PMID- 9755085
TI - Regulation of hepatic glutamine metabolism during exercise in the dog.
AB - The goal of this study was to determine how liver glutamine (Gln) metabolism
adapts to acute exercise in the 18-h-fasted dogs (n = 7) and in dogs that were
glycogen depleted by a 42-h fast (n = 8). For this purpose, sampling (carotid
artery, portal vein, and hepatic vein) and infusion (vena cava) catheters and
Doppler flow probes (portal vein, hepatic artery) were implanted under general
anesthesia. At least 16 days later an experiment, consisting of a 120-min
equilibration period, a 30-min basal sampling period, and a 150-min exercise
period was performed. At the start of the equilibration period, a constant-rate
infusion of [5-15N]Gln was initiated. Arterial Gln flux was determined by isotope
dilution. Gut and liver Gln release into and uptake from the blood were
calculated by combining stable isotopic and arteriovenous difference methods. The
results of this study show that 1) in the 18-h-fasted dog, approximately 10% and
approximately 35% of the basal Gln appearance in arterial blood is due to Gln
release from the gut and liver, respectively, whereas approximately 30% and
approximately 25% of the basal Gln disappearance is due to removal by these
tissues; 2) extending the fast to 42 h does not affect basal arterial Gln flux or
the contribution of the gut to arterial Gln fluxes but decreases hepatic Gln
release, causing a greater retention of gluconeogenic carbon by the liver; 3)
moderate-intensity exercise increases hepatic Gln removal from the blood
regardless of fast duration but does not affect the hepatic release of Gln; and
4) Gln plays an important role in channeling nitrogen into the ureagenic pathway
in the basal state, and this role is increased by approximately 80% in response
to exercise. These studies illustrate the quantitative importance of the
splanchnic bed contribution to arterial Gln flux during exercise and the ability
of the liver to acutely adapt to changes in metabolic requirements induced by the
combined effects of fasting and exercise.
PMID- 9755086
TI - Skeletal muscle phosphatidylcholine fatty acids and insulin sensitivity in normal
humans.
AB - The fatty acid composition of skeletal muscle membrane phospholipids (PL) is
known to influence insulin responsiveness in humans. However, the contribution of
the major PL of the outer (phosphatidylcholine, PC) and inner
(phosphatidylethanolamine, PE) layers of the sarcolemma to insulin sensitivity is
not known. Fatty acid composition of PC and PE from biopsies of vastus lateralis
from 27 normal men and women were correlated with insulin sensitivity determined
by the hyperinsulinemic euglycemic clamp technique at insulin infusion rates of
0.4, 1.0, and 10.0 mU . kg-1 . min-1. Significant variation in the half-maximal
insulin concentration (ED50) was observed in the normal volunteers (range 24.0
146.0 microU/ml), which correlated directly with fasting plasma insulin (r =
0.75, P < 0.0001). ED50 was inversely correlated with the degree of membrane
unsaturation (C20-C22 polyunsaturated fatty acids; r = 0. 58, P < 0.01) and
directly correlated with fatty acid elongation (ratio of 16:0 to 18:0, r = 0.45,
P < 0.05) in PC. However, no relationship between fatty acid composition and
insulin sensitivity was observed in PE (NS). These studies suggest that the fatty
acid composition of PC may be of particular importance in the relationship
between fatty acids and insulin sensitivity in normal humans.
PMID- 9755087
TI - Effects of estrogen and estrous cycle on glucocorticoid and catecholamine
responses to stress in sheep.
AB - There have been relatively few studies of the effects of estrogen on hormonal
responses to stress. We therefore studied changes in ACTH, cortisol,
norepinephrine (NE), and epinephrine (Epi) after stress induced by a barking dog
(audiovisual stressor) and insulin-induced hypoglycemia (metabolic stressor) in
ovariectomized sheep treated with estradiol or placebo and in intact sheep in the
follicular and luteal phases of the estrous cycle. Both stressors produced acute
increases in ACTH, cortisol, Epi, and NE. A high physiological dose of estradiol
significantly reduced the ACTH and cortisol responses to both stressors but did
not affect Epi and NE responses. Plasma ACTH and cortisol responses to both
stressors and Epi and NE responses to insulin were lower in the follicular than
in the luteal phase, but catecholamine responses to the audiovisual stressor did
not change during the estrous cycle. We conclude that in sheep, estrogen
attenuates glucocorticoid responses to stress and that hormonal changes during
the estrous cycle affect glucocorticoid responses to both metabolic and
audiovisual stressors and catecholamine responses to a metabolic stressor.
PMID- 9755088
TI - A modified high-fat diet induces insulin resistance in rat skeletal muscle but
not adipocytes.
AB - We hypothesized that variation in dietary fatty acid composition in rats fed a
high-fat diet had tissue-specific effects on glucose uptake sufficient to
maintain normal glucose tolerance. Rats were fed one of three diets for 3 wk. The
isocaloric high-fat-mixed oil (HF-mixed) diet and the high-fat-safflower oil (HF
saff) diet both provided 60% kcal fat, but fat composition differed [HF-mixed =
saturated, polyunsaturated (n-3 and n-6), and monounsaturated fatty acids; HF
saff = polyunsaturated fatty acids (mainly n-6)]. The control diet was high
carbohydrate (HCHO, 10% kcal fat). Insulin-stimulated 3-O-methylglucose uptake
into perfused hindlimb muscles was reduced in rats fed HF-saff and HF-mixed diets
compared with those fed HCHO diet (P < 0.02). Basal uptake increased in HF-saff-
and HF-mixed-fed rats vs. HCHO-fed rats (P < 0.04). In adipocytes, HF-saff
feeding decreased 2-deoxyglucose uptake vs. HF-mixed feeding and HCHO feeding (P
< 0.05), but 2-deoxyglucose uptake in HF-mixed-fed rats did not differ from that
in HCHO-fed rats (P > 0.05). Glucose tolerance was significantly reduced in HF
saff-fed rats but was unaffected by the HF-mixed diet. Therefore, in skeletal
muscle of rats, 1) feeding a diet high in fat induces a reduction in insulin
stimulated glucose uptake but 2) provides an increase in basal glucose uptake. In
contrast, 3) in adipocytes, insulin-stimulated glucose transport is reduced only
when the high-fat diet is high in n-6 polyunsaturated fatty acids but not when
fat comes from these mixed sources. Glucose intolerance becomes evident when
insulin resistance is seen in multiple tissues.
PMID- 9755089
TI - Dopaminergic control of angiotensin II-induced vasopressin secretion in vitro.
AB - Because dopamine influences arginine vasopressin (AVP) release, the present
studies were designed to ascertain the dopamine receptor subtype that potentiates
angiotensin II-induced AVP secretion in cultured hypothalamo-neurohypophysial
explants. Dopamine (a nonselective D1/D2 agonist), apomorphine (a D2 >> D1
agonist), and SKF-38393 (a selective D1 agonist) dose dependently increased AVP
secretion. Maximal AVP release was observed with 5 microM dopamine, 307 +/- 66% .
explant-1 . h-1, 1 microM SKF-38393, 369 +/- 41% . explant-1 . h-1, and 0.1
microM apomorphine, 374 +/- 67% . explant-1 . h-1. Selective D1 antagonism with 1
microM SCH-23390 blocked AVP secretion to values no different from basal.
Domperidone (D2 antagonist), phenoxybenzamine (nonselective adrenergic
antagonist), and prazosin (alpha1-antagonist) failed to prevent release. D1
antagonism also prevented AVP secretion to 1 microM angiotensin II [angiotensin
II, 422 +/- 87% . explant-1 . h-1 vs. angiotensin II plus SCH-23390, 169 +/- 28%
. explant-1 . h-1 (P < 0.05)], but D2 and alpha1-adrenergic blockade did not. In
contrast, AT1 receptor inhibition with 0.5 microM losartan blocked angiotensin II
but not dopamine-induced AVP release. AT2 antagonism had no effect. Although
subthreshold doses of the agonists did not increase AVP secretion (0. 05 microM
dopamine, 133 +/- 44% . explant-1 . h-1; 0.01 microM SKF-38393, 116 +/- 26% .
explant-1 . h-1;and 0.001 microM angiotensin II, 104 +/- 29% . explant-1 . h-1 ),
the combination of dopamine and angiotensin II provoked a significant rise in AVP
[420 +/- 83% . explant-1 . h-1 (P < 0.01)]. Similar results were observed with
SKF-38393 and angiotensin II, and the AVP response was blocked to basal levels by
either D1 or AT1 antagonism. These findings support a role for D1 receptor
activation to increase AVP release and mediate angiotensin II-induced AVP release
within the hypothalamo-neurohypophysial system. The data also suggest that the
combined subthreshold stimulation of receptors that use distinct intracellular
pathways can prompt substantial AVP release.
PMID- 9755090
TI - Systemic administration of amylin increases bone mass, linear growth, and
adiposity in adult male mice.
AB - Amylin is a peptide hormone cosecreted with insulin from the pancreatic beta
cells that can act as an osteoblast mitogen and as an inhibitor of bone
resorption. The effects on bone of its systemic administration are uncertain. The
present study addresses this question in adult male mice that were given daily
subcutaneous injections of amylin (10.5 microgram) or vehicle (n = 20 in each
group) for 4 wk. Histomorphometric indices of bone formation increased 30-100% in
the amylin-treated group, whereas resorption indices were reduced by
approximately 70% (P < 0.005 for all indices). Total bone volume in the proximal
tibia was 13.5 +/- 1.4% in control animals and 23.0 +/- 2.0% in those receiving
amylin (P = 0.0005). Cortical width, tibial growth plate width, tibial length,
body weight, and fat mass were all increased in the amylin-treated group. It is
concluded that systemic administration of amylin increases skeletal mass and
linear bone growth. This peptide has potential as a therapy for osteoporosis if
its bone effects can be dissociated from those on soft tissue mass.
PMID- 9755091
TI - Intrinsic mineralization defect in Hyp mouse osteoblasts.
AB - X-linked hypophosphatemia (XLH) is caused by inactivating mutations of PEX, an
endopeptidase of uncertain function. This defect is shared by Hyp mice, the
murine homologue of the human disease, in which a 3' Pex deletion has been
documented. In the present study, we report that immortalized osteoblasts derived
from the simian virus 40 (SV40) transgenic Hyp mouse (TMOb-Hyp) have an impaired
capacity to mineralize extracellular matrix in vitro. Compared with immortalized
osteoblasts from the SV40 transgenic normal mouse (TMOb-Nl), osteoblast cultures
from the SV40 Hyp mouse exhibit diminished 45Ca accumulation into extracellular
matrix (37 +/- 6 vs. 1,484 +/- 68 counts . min-1 . microgram protein-1) and
reduced formation of mineralization nodules. Moreover, in coculture experiments,
we found evidence that osteoblasts from the SV40 Hyp mouse produce a diffusible
factor that blocks mineralization of extracellular matrix in normal osteoblasts.
Our findings indicate that abnormal PEX in osteoblasts is associated with the
accumulation of a factor(s) that inhibits mineralization of extracellular matrix
in vitro.
PMID- 9755092
TI - Splanchnic retention of intraduodenal and intrajejunal glucose in healthy adults.
AB - Estimates of the spanchnic retention and appearance in the systemic circulation
of orally administered glucose vary among laboratories even after recently
identified sources of error have been accounted for [Livesey, G., P. D. G.
Wilson, J. R. Dainty, J. C. Brown, R. M. Faulks, M. A. Roe, T. A. Newman, J.
Eagles, F. A. Mellon, and R. Greenwood. Am. J. Physiol. 275 (Endocrinol. Metab.
38): E717-E728, 1998]. We questioned whether, in healthy humans, D-glucose
delivered intraluminally to the midjejunum appeared systemically as extensively
as that delivered intraduodenally. Subjects were infused over a period of 90 min
with 50 g of glucose in 1 liter of isotonic saline (incorporating 0.5 g D
[13C6]glucose) per 70 kg of body weight. Infusions were via enteral tubes
terminating approximately 15 and 100 cm postpylorus. The systemic appearance of
glucose was monitored by means of a primed-continuous intravenous infusion of D
[6,6-2H2]glucose. Whereas 98 +/- 2% (n = 7) of the duodenally infused glucose
appeared in the systemic circulation, only 35 +/- 9% (n = 7) of midjejunally
infused glucose did so, implying that 65 +/- 9% was retained in the splanchnic
bed. Either glucose was less efficiently absorbed at the midintestinal site or
hepatic glucose sequestration was increased 10-fold, or both. The proximal
intestine plays a key role in the delivery of glucose to the systemic
circulation, and the distal intestine potentially delivers more glucose to the
liver.
PMID- 9755093
TI - Simultaneous time-varying systemic appearance of oral and hepatic glucose in
adults monitored with stable isotopes.
AB - The rates (and extent) of appearance of glucose in arterialized plasma from an
oral glucose load and from liver (RaO, RaH) can be estimated in humans using
radioisotopes, but estimates vary among laboratories. We investigated the use of
stable isotopes and undertook 22 primed intravenous infusions of D-[6,6
2H2]glucose with an oral load including D-[13C6]glucose in healthy humans. The
effective glucose pool volume (VS) had a lower limit of 230 ml/kg body weight
(cf. 130 ml/kg commonly assumed). This VS in Steele's one-compartment model of
glucose kinetics gave a systemic appearance from a 50-g oral glucose load per 70
kg body weight of 96 +/- 3% of that ingested, which compared with a theoretical
value of approximately 95%. Mari's two-compartment model gave 100 +/- 3%. The two
models gave practically identical RaO and RaH at each point in time and a plateau
in the cumulative RaO when absorption was complete. Less than 3% of 13C was
recycled to [13C3]glucose, suggesting that recycling errors were practically
negligible in this study. Causes of variation among laboratories are identified.
We conclude that stable isotopes provide a reliable and safe alternative to
radioactive isotopes in these studies.
PMID- 9755094
TI - Lactate clamp: a method to measure lactate utilization in vivo.
AB - A lactate clamp method has been developed to quantify the whole body lactate
utilization in conscious, unstressed rats. Dichloroacetate (DCA), a known lactate
utilization enhancer, was used to validate the method. Fasting blood lactate
concentrations before the clamps were identical for DCA-treated (1 mmol/kg) and
control groups (1.65 +/- 0.37 vs. 1.65 +/- 0.19 mM). The animals received a
primed continuous lactate infusion for 90 min at variable rates to clamp the
blood lactate concentration at 2 mM. The steady-state (60-90 min) lactate
infusion rate, which represents the whole body lactate utilization in DCA-treated
animals, was 144% higher than that in the control animals (13.2 +/- 1.0 vs. 5.4
+/- 1.1 mg . kg-1 . min-1; P < 0.001). The markedly increased lactate infusion
rate indicates an enhanced lactate flux by DCA. To determine whether the
increased lactate infusion by DCA reflected reduced endogenous lactate
production, lactate production was measured. The results indicate that endogenous
lactate production was not affected by DCA. In conclusion, the lactate clamp
provides a sensitive and reliable method to assess lactate utilization in vivo, a
dynamic measurement that may not be clearly demonstrated by blood lactate
concentrations per se.
PMID- 9755095
TI - Regulation of extracellular matrix synthesis by TNF-alpha and TGF-beta1 in type
II cells exposed to coal dust.
AB - Type II pulmonary epithelial cells respond to anthracite coal dust PSOC 867 with
increased synthesis of extracellular matrix (ECM) components. Alveolar
macrophages modulate this response by pathways that may involve soluble
mediators, including tumor necrosis factor-alpha (TNF-alpha) or transforming
growth factor-beta1 (TGF-beta1). The effects of TNF-alpha (10 ng/ml) and/or TGF
beta1 (2 ng/ml) were thus investigated in dust-exposed primary type II cell
cultures. In control day 1 or day 3 cultures, TNF-alpha and/or TGF-beta1 had
little or no effect on the synthesis of type II cellular proteins, independent of
whether the cells were exposed to dust. With PSOC 867 exposure, where ECM protein
synthesis is elevated, TNF-alpha and TGF-beta1 further increased both the
absolute and relative rates of ECM synthesis on day 3 but had little effect on
day 1. Each mediator increased expression of fibronectin mRNA, as well as of ECM
fibronectin content, in a manner qualitatively similar to their effects on
synthesis. Thus TNF-alpha and TGF-beta1 modulate both ECM synthesis and
fibronectin content in coal dust-exposed type II cell cultures.
PMID- 9755096
TI - C-type natriuretic peptide expression and pulmonary vasodilation in hypoxia
adapted rats.
AB - Atrial and brain natriuretic peptides (ANP and BNP, respectively) are potent
pulmonary vasodilators that are upregulated in hypoxia-adapted rats and may
protect against hypoxic pulmonary hypertension. To test the hypothesis that C
type natriuretic peptide (CNP) also modulates pulmonary vascular responses to
hypoxia, we compared the vasodilator effect of CNP with that of ANP on pulmonary
arterial rings, thoracic aortic rings, and isolated perfused lungs obtained from
normoxic and hypoxia-adapted rats. We also measured CNP and ANP levels in heart,
lung, brain, and plasma in normoxic and hypoxia-adapted rats. Steady-state CNP
mRNA levels were quantified in the same organs by relative RT-PCR. CNP was a less
potent vasodilator than ANP in preconstricted thoracic aortic and pulmonary
arterial rings and in isolated lungs from normoxic and hypoxia-adapted rats.
Chronic hypoxia increased plasma CNP (15 +/- 2 vs. 6 +/- 1 pg/ml; P < 0.05) and
decreased CNP in the right atrium (35 +/- 14 vs. 65 +/- 17 pg/mg protein; P <
0.05) and in the lung (3 +/- 1 vs. 14 +/- 3 pg/mg protein; P < 0.05) but had no
effect on CNP in brain or right ventricle. Chronic hypoxia increased ANP levels
fivefold in the right ventricle (49 +/- 5 vs. 11 +/- 2 pg/mg protein; P < 0.05)
but had no effect on ANP in lung or brain. There was a trend toward decreased ANP
levels in the right atrium (2,009 +/- 323 vs. 2,934 +/- 397 pg/mg protein; P =
not significant). No differences in CNP transcript levels were observed between
the two groups of rats except that the right atrial CNP mRNA levels were lower in
hypoxia-adapted rats. We conclude that CNP is a less potent pulmonary vasodilator
than ANP in normoxic and hypoxia-adapted rats and that hypoxia raises circulating
CNP levels without increasing cardiopulmonary CNP expression. These findings
suggest that CNP may be less important than ANP or BNP in protecting against
hypoxic pulmonary hypertension in rats.
PMID- 9755097
TI - Human surfactant proteins A1 and A2 are differentially regulated during
development and by soluble factors.
AB - An RT-PCR method for the relative quantitation of the mRNAs for human surfactant
protein (SP) A1 and SP-A2 was developed, verified, and then utilized to determine
the relative levels of these mRNAs in fetal and adult lung samples in vivo, as
well as in cultured human fetal lung explants and H441 cells. For the cultured
tissue and cells, we assessed the effects of a variety of soluble factors known
to modulate total SP-A. Comprehensive analysis revealed many significant
findings, including the following: both mRNAs were expressed as early as 15 wk of
gestation; throughout midgestation, SP-A1 was present at higher levels than SP
A2, with an average ratio of 30:1. In the adult lung, SP-A1 mRNA was present at
lower levels than SP-A2, with a ratio of 0.4:1, whereas in H441 cells, the ratio
was 0.85:1. In fetal lung cultured for 4 days, both mRNAs increased, with a
greater increase in SP-A2 (97-fold) than in SP-A1 (15-fold), resulting in a final
ratio of 4:1. Differential regulation was demonstrated for 8-(4-chlorophenylthio)
cAMP, interferon (IFN)-gamma, tumor necrosis factor-alpha, and transforming
growth factor (TGF)-beta in the human fetal lung explant system, with SP-A2 being
more affected, and for IFN-gamma and TGF-beta in the H441 cells, where SP-A1
showed greater regulation. Of the soluble factors tested, IFN-gamma and TGF-beta
had the most potent and consistent effects in both systems.
PMID- 9755098
TI - Osmotic stress induces both secretion and apoptosis in rat alveolar type II
cells.
AB - The aim of this study was to analyze the effects of osmotic shock and
secretagogues such as ATP and 12-O-tetradecanoylphorbol 13-acetate (TPA) on
various intracellular signaling pathways in primary cultures of alveolar type II
cells and examine their potential role in regulating events such as secretion and
apoptosis in these cells. Sorbitol-induced osmotic stress caused the sustained
release of [3H]phosphatidylcholine ([3H]PC) from primary cultures of rat alveolar
type II cells prelabeled with [3H]choline chloride. This release was not
dependent on protein kinase C because downregulation of the major protein kinase
C isoforms (alpha, betaII, delta, and eta) expressed in alveolar type II cells
had no effect on [3H]PC secretion. Sorbitol, as well as the known secretagogues
TPA and ATP, activated extracellular signal-regulated kinase. Although an
inhibitor of the extracellular signal-regulated kinase cascade, PD-98059, blocked
this activation, it had no effect on the release of [3H]PC. Sorbitol and
ultraviolet C radiation, but not TPA or ATP, were also found to activate both p38
and stress-activated protein kinase/c-Jun NH2-terminal kinase. Furthermore, both
sorbitol and ultraviolet C radiation induced apoptosis in alveolar type II cells
as demonstrated by Hoechst 33258 staining of the condensed nuclei, the generation
of DNA ladders, and the activation of caspases. The data indicate that multiple
signaling pathways are activated by traditional secretagogues such as TPA and ATP
and by cellular stresses such as osmotic shock and that these may be involved in
regulating secretory and apoptotic events in alveolar type II cells.
PMID- 9755100
TI - Alveolar type II-like cells release G-CSF as neutrophil chemotactic activity.
AB - We evaluated the potential of A549 cells, an alveolar type II epithelial cell
line, to release granulocyte colony-stimulating factor (G-CSF), in addition to
interleukin (IL)-8 and leukotriene B4, as neutrophil chemotactic activity (NCA).
Human recombinant IL-1beta stimulated A549 cells to release NCA in a time- and
dose-dependent fashion. The released NCA was blocked by mouse anti-human G-CSF
polyclonal antibody. Molecular-sieve column chromatography revealed that IL-1beta
induced the release of a 19- to 20-kDa chemotactic mass that was inhibited by
anti-human G-CSF antibody. IL-1beta stimulated the release of G-CSF in a dose
dependent fashion, but the time-dependent profile of G-CSF showed that the
concentration of G-CSF declined after 48 h. Tumor necrosis factor (TNF)-alpha,
Escherichia coli lipopolysaccharide (LPS), and bradykinin (BK) stimulated A549
cells to release NCA that was inhibited by anti-G-CSF antibody. The release of G
CSF in response to TNF-alpha, LPS, and BK was significantly increased. The
similar concentrations of human recombinant G-CSF (10-1,000 pg/ml) as in the
supernatant fluid induced neutrophil chemotaxis. G-CSF mRNA was expressed time
and dose dependently at 4 h and declined after 4 h in response to IL-1beta as
evaluated by RT-PCR. The expression of G-CSF mRNA was also observed by TNF-alpha,
LPS, and BK stimulation. These data suggest that type II alveolar epithelial
cells may produce G-CSF as NCA and may participate in the regulation of leukocyte
extravasation.
PMID- 9755099
TI - Surfactant protein A inhibits T cell proliferation via its collagen-like tail and
a 210-kDa receptor.
AB - Investigation of possible mechanisms to describe the hyporesponsiveness of
pulmonary leukocytes has led to the study of pulmonary surfactant and its
constituents as immune suppressive agents. Pulmonary surfactant is a phospholipid
protein mixture that reduces surface tension in the lung and prevents collapse of
the alveoli. The most abundant protein in this mixture is a hydrophilic molecule
termed surfactant-associated protein A (SP-A). Previously, we showed that bovine
(b) SP-A can inhibit human T lymphocyte proliferation and interleukin-2
production in vitro. Results presented in this investigation showed that
different sources of human SP-A and bSP-A as well as recombinant rat SP-A
inhibited human T lymphocyte proliferation in a dose-dependent manner. A
structurally similar collagenous protein, C1q, did not block the in vitro
inhibitory action of SP-A. The addition of large concentrations of mannan to SP-A
treated cultures also did not disrupt inhibition, suggesting that the effect is
not mediated by the carbohydrate recognition domain of SP-A. Use of recombinant
mutant SP-As revealed that a 36-amino acid Arg-Gly-Asp (RGD) motif-containing
span of the collagen-like domain was responsible for the inhibition of T cell
proliferation. A polyclonal antiserum directed against an SP-A receptor (SP-R210)
completely blocked the inhibition of T cell proliferation by SP-A. These results
emphasize a potential role for SP-A in dampening lymphocyte responses to
exogenous stimuli. The data also provide further support for the concept that SP
A maintains a balance between the clearance of inhaled pathogens and protection
against collateral immune-mediated damage.
PMID- 9755101
TI - Phosphodiesterase expression in human epithelial cells.
AB - Epithelial cells play a critical role in airway inflammation and have the
capacity to produce many inflammatory mediators, including bioactive lipids and
proinflammatory cytokines. Intracellular levels of cAMP and cGMP are important in
the control of inflammatory cell function. These cyclic nucleotides are
inactivated via a family of phosphodiesterase (PDE) enzymes, providing a possible
site for drug intervention in chronic inflammatory conditions. We studied the
expression of PDE activity in an epithelial cell line (A549) and in primary human
airway epithelial cells (HAECs). We measured PDE function using specific
inhibitors to identify the PDE families present and used RT-PCR to elucidate the
expression of PDE isogenes. Both A549 cells and HAECs predominantly expressed
PDE4 activity, with lesser PDE1, PDE3, and PDE5 activity. RT-PCR identified
HSPDE4A5 and HSPDE4D3 together with HSPDE7. Inhibition of PDE4 and PDE3 reduced
secretion by these cells. Epithelial PDE may be an important target for PDE4
inhibitors in the development of the control of asthmatic inflammation,
particularly when delivered via the inhaled route.
PMID- 9755102
TI - Sulfation of extracellular matrices modifies growth factor effects on type II
cells on laminin substrata.
AB - The alveolar basement membrane contains a variety of extracellular matrix (ECM)
molecules, including laminin and sulfated glycosaminoglycans of proteoglycans.
These mixtures exist within microdomains of differing levels of sulfate, which
may specifically interact to be key determinants of the known capacity of the
type II cell to respond to certain growth factors. Isolated type II cells were
exposed to either acidic fibroblast growth factor (FGF-1), basic fibroblast
growth factor (FGF-2), or keratinocyte growth factor (KGF; FGF-7) on culture
wells precoated with laminin alone or in combination with chondroitin sulfate
(CS), high-molecular-weight heparin, or their desulfated forms. Desulfated
heparin significantly elevated FGF-1- and FGF-2-stimulated DNA synthesis, whereas
desulfated CS and N-desulfated heparin elevated FGF-7-stimulated DNA synthesis by
type II cells on laminin substrata. When FGF-1 was mixed into the various test
matrix substrata, DNA synthesis was significantly increased in all cases. These
results demonstrated that decreased levels of sulfate in ECM substrata act to
upregulate responses to heparin-binding growth factors by alveolar epithelial
cells on laminin substrata.
PMID- 9755103
TI - O2-sensitive K+ channels in neuroepithelial body-derived small cell carcinoma
cells of the human lung.
AB - Neuroepithelial bodies act as airway O2 sensors, but studies of their activity at
the cellular level have been severely limited because they are present at such a
low density in lung tissue. Small cell lung carcinoma (SCLC) cells are believed
to be derived from neuroepithelial body cells and may represent a model system
for investigating the mechanisms of airway chemoreception. Here we have used the
whole cell patch-clamp technique to investigate the effects of acute hypoxia on
voltage-gated ionic currents and membrane potential in H-146 SCLC cells. Step
depolarizations evoked transient inward currents due to activation of Na+ and
Ca2+ channels, followed by outward K+ currents. K+ currents were partially
inhibited by 200 microM Cd2+ (indicative of the presence of a Ca2+-dependent
component of the K+ current) and were inhibited by tetraethylammonium (TEA) in a
concentration-dependent manner, although even at 100 mM TEA, a residual K+
current could be detected. Hypoxia (PO2 15-20 mmHg) caused a reversible
inhibition of outward K+ currents without affecting inward currents. Inhibition
by hypoxia was also observed in the presence of Cd2+. Hypoxia and TEA caused
membrane depolarization in H-146 cells, and their effects appeared additive.
These findings indicate that H-146 cells possess O2-sensitive, Ca2+-independent
K+ channels that can influence cell membrane potential. SCLC cells may,
therefore, represent a good model for investigating the mechanisms underlying O2
sensing by airway chemoreceptor cells.
PMID- 9755104
TI - Nitric oxide inhibits lipopolysaccharide-induced apoptosis in pulmonary artery
endothelial cells.
AB - Our group recently reported that cultured sheep pulmonary artery endothelial
cells (SPAECs) became resistant to lipopolysaccharide (LPS)-induced apoptosis
several days after constitutive synthesis of nitric oxide (NO) after adenoviral
(Ad) transfer of inducible NO synthase (iNOS) or exposure to the NO donor S
nitroso-N-acetylpenicillamine (SNAP) (E. Tzeng, Y.-M. Kim, B. R. Pitt, A.
Lizonova, I. Kovesdi, and T. R. Billiar. Surgery 122: 255-263, 1997). In the
present study, we confirmed this observation by establishing stable transfectants
after retroviral gene transfer [replication-deficient retrovirus (DFG)] of human
iNOS (DFG-iNOS) SPAECs and then used all three approaches (Ad, DFG, and SNAP) to
determine underlying mechanisms of this phenomenon. Continuous endogenous
production of NO in itself did not cause apoptosis as assessed by phase-contrast
microscopy, nuclear morphology, and internucleosomal DNA fragmentation. Prolonged
(72-96 h) synthesis of NO, however, after DFG- or replication-deficient
adenovirus (Ad. CMV)-iNOS or SNAP (100 microM, 96 h) inhibited LPS-induced
apoptosis. The kinetics of such protection suggested that NO may be inducing
other gene products. Ad-mediated transfer of manganese superoxide dismutase
(MnSOD) decreased the sensitivity of wild-type SPAECs to LPS-induced apoptosis.
MnSOD, however, was not induced in an NG-monomethyl-L-arginine (L-NMMA)-sensitive
time-dependent fashion after Ad.CMV-iNOS. Other inducible genes that may be
affected by NO and that may protect against potential oxidant-mediated LPS
induced apoptosis including 70-kDa heat shock protein, heme oxygenase-1,
metallothionein, and Bcl-2 also were not elevated in an L-NMMA-sensitive, time
dependent fashion. Although the candidate gene product underlying NO-induced
protection remains unclear, we did note that prolonged synthesis of NO inhibited
LPS-induced activation of an interleukin-1beta-converting enzyme-like cysteine
protease (cysteine protease protein-32-like) in a dithiothreitol-sensitive
fashion, suggesting that S-nitrosylation of an important downstream target of
convergence of apoptotic signals may contribute to the sensitivity of SPAECs to
LPS.
PMID- 9755105
TI - ET-1 modulates KCa-channel activity and arterial tension in normoxic and hypoxic
human pulmonary vasculature.
AB - The molecular mechanisms by which endothelin (ET)-1 induces pulmonary
hypertension are poorly understood. We investigated the effects of ET-1 on
outward K+ currents of normoxic and chronically hypoxic human pulmonary arterial
(PA) smooth muscle cells (HPSMCs). In normoxic HPSMCs, ET-1 has dual effects. In
intact cells, 5 nM ET-1 activates the large-conductance and Ca2+-activated K+
(KCa)-channel current [IK(Ca)] by increasing intracellular Ca2+ concentration,
whereas it directly inhibits IK(Ca) in isolated membrane patches. At a higher
concentration (10 nM), ET-1-induced IK(Ca) inhibition predominates. In hypoxic
HPSMCs, ET-1 at 5 nM significantly reduces IK(Ca). The ETA-receptor antagonist BQ
123 reverses the ET-1-induced decrease in IK(Ca). Chronic BQ-123 treatment also
prevents the hypoxia-induced decrease in IK(Ca). In PA rings obtained from human
organ donors, ET-1 causes a concentration-dependent increase in tension. The ET-1
mediated increase in tension is reversed by a KCa-channel agonist. The increase
in tension at the highest concentration studied (9 nM) was more pronounced in PA
rings obtained from patients with chronic obstructive pulmonary disease. These
results imply that an ET-1-induced decrease in IK(Ca) contributes to chronic
hypoxia-induced pulmonary hypertension.
PMID- 9755106
TI - Hydrolysis of surfactant-associated phosphatidylcholine by mammalian secretory
phospholipases A2.
AB - Hydrolysis of surfactant-associated phospholipids by secretory phospholipases A2
is an important potential mechanism for surfactant dysfunction in inflammatory
lung diseases. In these conditions, airway secretory phospholipase A2 (sPLA2)
activity is increased, but the type of sPLA2 and its impact on surfactant
function are not well understood. We examined in vitro the effect of multiple
secretory phospholipases A2 on surfactant, including their ability to 1) release
free fatty acids, 2) release lysophospholipids, and 3) increase the minimum
surface tension (gammamin) on a pulsating bubble surfactometer. Natural porcine
surfactant and Survanta were exposed to mammalian group I (recombinant porcine
pancreatic) and group II (recombinant human) secretory phospholipases A2. Our
results demonstrate that mammalian group I sPLA2 hydrolyzes phosphatidylcholine
(PC), producing free fatty acids and lysophosphatidylcholine, and increases
gammamin. In contrast, mammalian group II sPLA2 demonstrates limited hydrolysis
of PC and does not increase gammamin. Group I and group II secretory
phospholipases A2 from snake venom hydrolyze PC and inhibit surfactant function.
In summary, mammalian secretory phospholipases A2 from groups I and II differ
significantly from each other and from snake venom in their ability to hydrolyze
surfactant-associated PC.
PMID- 9755107
TI - Role of G proteins in agonist-induced Ca2+ sensitization of tracheal smooth
muscle.
AB - Increased sensitivity to intracellular Ca2+ concentration ([Ca2+]) is an
important mechanism for agonist-induced contraction of airway smooth muscle, but
the signal transduction pathways involved are uncertain. We studied Ca2+
sensitization with acetylcholine (ACh) and endothelin (ET)-1 in porcine tracheal
smooth muscle by measuring contractions at a constant [Ca2+] in strips
permeabilized with alpha-toxin or beta-escin. The peptide inhibitor G protein
antagonist 2A (GP Ant-2A), which has selectivity for Gq over Gi, inhibited
contractile responses to ET-1, ACh, and guanosine 5'-O-(3-thiotriphosphate)
(GTPgammaS), but the proportional inhibition of ACh responses was less than that
of ET-1. Pretreatment with pertussis toxin reduced ACh contractions but had no
effect on those of ET-1 or GTPgammaS. Clostridium botulinum C3 exoenzyme, which
inactivates Rho family monomeric G proteins, caused similar reductions in
contractile responses to ACh, ET-1, and GTPgammaS. Farnesyltransferase
inhibition, which inhibits Ras G proteins, reduced responses to ET-1. We conclude
that the heterotrimeric G proteins Gq and Gi both contribute to Ca2+
sensitization by ACh, whereas ET-1 responses involve Gq but not Gi. Both Gq and
Gi pathways likely involve Rho family small G proteins. A Ras-mediated pathway
also contributes to Ca2+ sensitization by ET-1 in airway smooth muscle.
PMID- 9755108
TI - Involvement of cytochrome P-450 enzyme activity in the control of microvascular
permeability in canine lung.
AB - Products of cytochrome P-450 enzymes may play a role in capacitative Ca2+ entry
in endothelial cells, which can promote a rise in vascular permeability.
Thapsigargin (150 nM) stimulated capacitative Ca2+ entry and increased the
capillary filtration coefficient (Kf,c) in isolated normal canine lung lobes.
Pretreatment of the lobes with cytochrome P-450 inhibitors clotrimazole (10
microM) or 17-octadecynoic acid (5 microM) abolished the thapsigargin-induced
increases in Kf,c. Because clotrimazole also blocks Ca2+-activated K+ channels,
the K+-channel blocker tetraethylammonium (10 mM) was used to ensure that
permeability was not influenced by this mechanism. Tetraethylammonium did not
affect thapsigargin-induced permeability. The effects of the cytochrome P-450
arachidonic acid metabolite 5,6-epoxyeicosatrienoic acid (EET) were also
investigated in lobes taken from control dogs and dogs with pacing-induced heart
failure (paced at 245 beats/min for 4 wk). 5,6-EET (10 microM) significantly
increased Kf,c in lobes from the control but not from the paced animals. We
conclude that cytochrome P-450 metabolites are involved in mediating
microvascular permeability in normal canine lungs, but an absence of 5,6-EET
after heart failure does not explain the resistance of lungs from these animals
to permeability changes.
PMID- 9755109
TI - O2-induced ENaC expression is associated with NF-kappaB activation and blocked by
superoxide scavenger.
AB - Cultured rat fetal distal lung epithelial cells (FDLEs), when switched from fetal
(3%) to postnatal (21%) O2 concentrations, have increased epithelial Na+ channel
(ENaC) mRNA levels and amiloride-sensitive Na+ transport [O. Pitkanen, A. K.
Tanswell, G. Downey, and H. O'Brodovich. Am. J. Physiol. 270 (Lung Cell. Mol.
Physiol. 14): L1060-L1066, 1996]. The mechanisms by which O2 mediates these
effects are unknown. After isolation, FDLEs were kept at 3% O2 overnight, then
switched to 21% O2 (3-21% O2 group) or maintained at 3% O2 (3-3% O2 group) for 48
h. The amiloride-sensitive short-circuit current (Isc) in the 3-21% O2 group was
double that in the 3-3% O2 group. Amiloride-sensitive Isc could not be induced by
medium conditioned by 21% O2-exposed FDLEs but was reversed by returning the
cells to 3% O2. Neither the cyclooxygenase inhibitor ibuprofen, liposome
encapsulated catalase, nor hydroperoxide scavengers (U-74389G or Trolox) blocked
the O2-induced amiloride-sensitive Isc. In contrast, the cell-permeable
superoxide scavenger tetramethylpiperidine-N-oxyl (TEMPO) eliminated the O2
induced increases in amiloride-sensitive Isc and ENaC mRNA levels. The switch
from 3 to 21% O2 induced the transcription factor nuclear factor-kappaB, which
could also be blocked by TEMPO. We conclude that 1) the O2-induced increase in
amiloride-sensitive Isc is reversible and 2) the O2-induced increase in amiloride
sensitive Isc and ENaC mRNA levels is associated with activation of nuclear
factor-kappaB and may be mediated, at least in part, by superoxide.
PMID- 9755110
TI - Tobacco smoke induces both apoptosis and necrosis in mammalian cells:
differential effects of HSP70.
AB - Tobacco smoke (TS) has been implicated as a major risk factor in human pulmonary
diseases including cancer. In this study, we used TS as a model of oxidative
stress. TS-mediated oxidative stress has been shown to induce protein oxidation,
DNA damage, and cell death. Here we investigated, in human and rodent cell lines,
whether TS induces cell death by apoptosis or by necrosis. As described for
classic oxidants, TS induced apoptosis at low concentrations and necrosis at
higher concentrations. We have previously described the induction of heat shock
(HS) protein (HSP) (in particular, HSP70) in human monocytes exposed to TS. HSP70
is implicated in the regulation of cell injury and cell death and, in particular,
modulates apoptosis, as does the antiapoptotic oncoprotein Bcl-2. At both
apoptotic and necrotic concentrations, TS induced a dose-dependent HSP70
expression, whereas Bcl-2 was induced only at necrotic concentrations. TS- or HS
induced HSP had no protective effects either on apoptosis or on necrosis, but
HSP70 overexpression prevented TS-induced necrosis and consequently led to
increased apoptosis. These results might reconcile the apparently contradictory
data previously reported on the effects of HSP on apoptosis.
PMID- 9755111
TI - Keratinocyte growth factor promotes alveolar epithelial cell DNA repair after
H2O2 exposure.
AB - Alveolar epithelial cell (AEC) injury and repair are important in the
pathogenesis of oxidant-induced lung damage. Keratinocyte growth factor (KGF)
prevents lung damage and mortality in animals exposed to various forms of oxidant
stress, but the protective mechanisms are not yet established. Because DNA strand
break (DNA-SB) formation is one of the earliest cellular changes that occurs
after cells are exposed to an oxidant stress, we determined whether KGF reduces
H2O2-induced pulmonary toxicity by attenuating AEC DNA damage. KGF (10-100 ng/ml)
decreased H2O2 (0.05-0.5 mM)-induced DNA-SB formation in cultured A549 and rat
alveolar type II cells measured by an alkaline unwinding, ethidium bromide
fluorometric technique. The protective effects of KGF were independent of
alterations in catalase, glutathione (GSH), or the expression of bcl-2 and bax,
two protooncogenes known to regulate oxidant-induced apoptosis. Actinomycin D and
cycloheximide abrogated protective effects of KGF. Furthermore, protection by KGF
was completely blocked by 1) genistein, a tyrosine kinase inhibitor; 2)
staurosporine and calphostin C, protein kinase C (PKC) inhibitors; and 3)
aphidicolin, butylphenyl dGTP, and 2',3'-dideoxythymidine 5'-triphosphate,
inhibitors of DNA polymerase. We conclude that KGF attenuates H2O2-induced DNA-SB
formation in cultured AECs by mechanisms that involve tyrosine kinase, PKC, and
DNA polymerases. These data suggest that the ability of KGF to protect against
oxidant-induced lung injury is partly due to enhanced AEC DNA repair.
PMID- 9755112
TI - Role of Ca2+/calmodulin-dependent phosphatase 2B in thrombin-induced endothelial
cell contractile responses.
AB - Thrombin-induced Ca2+ mobilization, activation of Ca2+/calmodulin-dependent
myosin light chain (MLC) kinase (MLCK), and increased phosphorylation of MLCs
precede and are critical to endothelial cell (EC) barrier dysfunction. Net MLC
dephosphorylation after thrombin is nearly complete by 60 min and involves type 1
phosphatase (PPase 1) activity. We now report that thrombin does not alter total
PPase 1 activity in EC homogenates but rather decreases myosin-associated PPase 1
activity. The PPase 1 inhibitor calyculin fails to prevent thrombin-induced MLC
dephosphorylation. However, thrombin significantly increased the activity of Ca2+
dependent PPase 2B in EC homogenates (approximately 1.5- to 2-fold), with PPase
2B activation correlating with phosphorylation of the PPase 2B catalytic subunit.
Western immunoblotting revealed PPase 2B to be present in cytoskeletal EC
fractions, with specific PPase 2B inhibitors such as cyclosporin (200 nM) and
deltamethrin (100 nM to 1 microM) attenuating thrombin-induced cytoskeletal
protein dephosphorylation, including EC MLC dephosphorylation. These results
suggest a model whereby thrombin-inducible contraction is determined by the
phosphorylation status of EC MLC regulated by the balance between EC MLCK, PPase
1 (constitutive), and PPase 2B (inducible) activities.
PMID- 9755113
TI - Intravenous keratinocyte growth factor protects against experimental pulmonary
injury.
AB - Keratinocyte growth factor (KGF) administered by intratracheal instillation is
well documented to stimulate the proliferation of alveolar and bronchial cells.
In the present study, intravenous KGF was also shown to stimulate the
proliferation of alveolar and bronchial cells in mice and rats, although to a
lesser degree than intratracheal KGF. Despite the decreased potency of
intravenous KGF on pulmonary cell 5-bromo-2'-deoxyuridine incorporation compared
with intratracheal KGF, intravenous KGF was very effective in preventing
experimental bleomycin-induced pulmonary dysfunction, weight loss, and mortality
in either mice or rats and experimental hyperoxia-induced mortality in mice. The
effectiveness of intravenous administration of KGF in preventing lung injury
suggests that the mechanisms of the protective effect of KGF may involve more
than pulmonary cell proliferation and also suggests the potential use of systemic
KGF for clinical trials in settings of pulmonary injury.
PMID- 9755114
TI - Immunotargeting of catalase to ACE or ICAM-1 protects perfused rat lungs against
oxidative stress.
AB - The pulmonary endothelium is susceptible to oxidative insults. Catalase
conjugated with monoclonal antibodies (MAbs) against endothelial surface
antigens, angiotensin-converting enzyme (MAb 9B9) or intercellular adhesion
molecule-1 (MAb 1A29), accumulates in the lungs after systemic injection in rats
(V. Muzykantov, E. Atochina, H. Ischiropoulos, S. Danilov, and A. Fisher. Proc.
Natl. Acad. Sci. USA 93: 5213-5218, 1996). The present study characterizes the
augmentation of antioxidant defense by these antibody-catalase conjugates in
isolated rat lungs perfused for 1 h with catalase conjugated with either MAb 9B9,
MAb 1A29, or control mouse IgG. Approximately 20% of the injected dose of Ab-125I
catalase accumulated in the perfused rat lungs (vs. <5% for IgG-125I-catalase).
After elimination of nonbound material, the lungs were perfused further for 1 h
with 5 mM hydrogen peroxide (H2O2). H2O2 induced an elevation in tracheal and
pulmonary arterial pressures (126 +/- 7 and 132 +/- 5%, respectively, of the
control level), lung wet-to-dry weight ratio (7.1 +/- 0.4 vs. 6.0 +/- 0.01 in the
control lungs), and ACE release into the perfusate (436 +/- 20 vs. 75 +/- 7 mU in
the control perfusates). Both MAb 9B9-catalase and MAb 1A29-catalase
significantly attenuated the H2O2-induced elevation in 1) angiotensin-converting
enzyme release to the perfusate (215 +/- 14 and 217 +/- 38 mU, respectively), 2)
lung wet-to-dry ratio (6.25 +/- 0.1 and 6.3 +/- 0.3, respectively), 3) tracheal
pressure (94 +/- 4 and 101 +/- 4%, respectively, of the control level), and 4)
pulmonary arterial pressure (103 +/- 3 and 104 +/- 7%, respectively, of the
control level). Nonconjugated catalase, nonconjugated antibodies, nonspecific
IgG, and IgG-catalase conjugate had no protective effect, thus confirming the
specificity of the effect of MAb-catalase. These results support a strategy of
catalase immunotargeting for protection against pulmonary oxidative injury.
PMID- 9755115
TI - Temporal, spatial, and oxygen-regulated expression of hypoxia-inducible factor-1
in the lung.
AB - Hypoxia-inducible factor (HIF)-1 is a basic helix-loop-helix transcription factor
that transactivates genes encoding proteins that participate in homeostatic
responses to hypoxia. Several of these downstream gene products, such as
erythropoietin, vascular endothelial growth factor, heme oxygenase-1, and
inducible nitric oxide synthase, may contribute to the pathogenesis of pulmonary
hypertension. Previous studies demonstrated increased HIF-1 mRNA levels in rats
and mice subjected to hypoxia. In this study, we have demonstrated spatial,
temporal, and O2-dependent expression of HIF-1 protein. Immunoblot analysis
revealed hypoxic induction of HIF-1 in all cultured pulmonary cell types assayed,
including those derived from pulmonary arterial endothelium and smooth muscle,
bronchial epithelium, alveolar macrophages, alveolar epithelium, and
microvascular endothelium. In contrast to all other cell types, pulmonary
arterial smooth muscle cells expressed HIF-1 under nonhypoxic conditions.
Immunohistochemistry and immunoblot analysis of ferret lungs demonstrated
pulmonary expression of HIF-1 in vivo. HIF-1 protein expression was induced
maximally when lungs were ventilated with 0 or 1% O2 for 4 h. On reoxygenation,
HIF-1 was rapidly degraded, with a half-life of <1 min. These findings
demonstrate that HIF-1 expression is tightly coupled to O2 concentration in vivo
and are consistent with the involvement of HIF-1 in the physiological and
pathophysiological responses to hypoxia in the lung.
PMID- 9755116
TI - Regulation of ciliary beat frequency by both PKA and PKG in bovine airway
epithelial cells.
AB - Ciliary beating is required for the maintenance of lung mucociliary transport. We
investigated the role of cyclic nucleotide-dependent protein kinases in
stimulating ciliary beat frequency (CBF) in bovine bronchial epithelial cells
(BBECs). cAMP-dependent protein kinase (PKA) activity and cGMP-dependent protein
kinase (PKG) activity were distinguished after DEAE-Sephacel chromatography of
BBEC extracts. cAMP levels and PKA activity are increased in BBECs stimulated
with 0.01-1 mM isoproterenol, with a corresponding increase in CBF. cGMP levels
and PKG activity are increased in BBECs stimulated with 0.1-10 microM sodium
nitroprusside, with a corresponding increase in CBF. Direct protein kinase
activating analogs of cAMP and cGMP (dibutyryl cAMP and 8-bromo-cGMP,
respectively) also activate their specific kinases and stimulate CBF.
Preincubation of BBECs with inhibitors of PKA or PKG [KT-5720 or Rp-8-(p
chlorophenylthio)-guanosine 3',5'-cyclic monophosphothioate] results in the
inhibition of specific kinase activity as well as in the inhibition of CBF. These
studies suggest that the activation of either PKA or PKG can lead to the
stimulation of CBF in bovine airway epithelium.
PMID- 9755117
TI - Increased expression of heat shock protein-70 protects A549 cells against
hyperoxia.
AB - Acute and chronic lung injury secondary to hyperoxia remains an important
complication in critically ill patients, and, consequently, there is interest in
developing strategies to protect the lung against hyperoxia. Heat shock proteins
(HSPs) confer protection against a broad array of cytotoxic agents. In this
study, we tested the hypothesis that increased expression of the 70-kDa HSP
(HSP70) would protect cultured human respiratory epithelium against hyperoxia.
Recombinant A549 cells were generated in which human HSP70 was increased by
stable transfection with a plasmid containing human HSP70 cDNA under control of
the cytomegalovirus promoter (A549-HSP70 cells). A549-HSP70 cells exposed to
hyperoxia had greater acute survival rates and clonogenic capacity compared with
wild-type A549 cells and with control cells stably transfected with the empty
expression plasmid. Hyperoxia-mediated lipid peroxidation and ATP depletion were
also attenuated in A549-HSP70 cells exposed to hyperoxia. Increased expression of
HSP70 did not detectably alter mRNA levels of the intracellular antioxidants
manganese superoxide dismutase, catalase, and glutathione peroxidase.
Collectively, these data demonstrate a specific in vitro protective role for
HSP70 against hyperoxia and suggest that potential mechanisms of protection
involve attenuation of hyperoxia-mediated lipid peroxidation and ATP depletion.
PMID- 9755118
TI - Relevance of extracellular matrix, its receptors, and cell adhesion molecules in
mammalian nephrogenesis.
AB - Mammalian nephrogenesis begins by the reciprocal interaction of the ureteric bud
with the undifferentiated mesenchyme. The mesenchyme differentiates into an
epithelial phenotype with the development of the glomerulus and proximal and
distal tubules. At the same time, the mesenchyme stimulates the branching
morphogenesis of the ureteric bud that differentiates into the collecting ducts.
These inductive interactions and differentiation events are modulated by a number
of macromolecules, including the extracellular matrix (ECM), integrin receptors,
and cell adhesion molecules. Many of these macromolecules exhibit spatiotemporal
developmental regulation in the metanephros. Some are expressed in the
mesenchyme, whereas others appear in the ureteric bud epithelia. The molecules
expressed in the mesenchyme or at the epithelial:mesenchymal interface may serve
as ligands while those in the epithelia serve as the receptors. In such a
scenario the ligand and the receptor would be ideally suited for
epithelial:mesenchymal paracrine/juxtacrine interactions that are also influenced
by RGD sequences and Ca2+ binding domains of the ECM proteins and their
receptors. This review addresses the role of such interactions in metanephric
development.
PMID- 9755119
TI - Hypertonicity activates MAP kinases and inhibits HCO-3 absorption via distinct
pathways in thick ascending limb.
AB - Mitogen-activated protein (MAP) kinases are activated by osmotic stress in a
variety of cells, but their function and regulation in renal tubules is poorly
understood. The present study was designed to examine the osmotic regulation of
MAP kinases in the medullary thick ascending limb (MTAL) of the rat and to
determine their possible role in the hyperosmotic inhibition of HCO-3 absorption
in this segment. Tissues from the inner stripe of the outer medulla and
microdissected MTALs were incubated at 37 degreesC in control (290 mosmol/kgH2O)
or hyperosmotic (300 mM added mannitol) solution for 15 min. Activities of
extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and
p38 MAP kinase were then measured using immune complex assays. Hyperosmolality
increased p38 MAP kinase activity (2.3-fold) and ERK activity (2.0-fold) but had
no effect on JNK activity (1.1-fold). Exposure to hyperosmolality for various
times showed that the activation of p38 MAP kinase was rapid (=5 min) and was
sustained for up to 60 min, whereas the activation of ERK was transient (ERK
activity peaked at 15 min, then declined to basal levels at 30 min). Pretreatment
with the MAP kinase kinase inhibitor PD98059 (15 microM) blocked the hyperosmotic
activation of p38 MAP kinase and ERK but did not prevent hyperosmotic inhibition
of HCO-3 absorption. These results show that hyperosmolality differentially
activates p38 MAP kinase and ERK in the MTAL. In contrast, we found no evidence
for involvement of JNK in the early response to hyperosmotic stress. Eliminating
the activation of p38 MAP kinase and ERK does not prevent hyperosmotic inhibition
of HCO-3 absorption, suggesting that hyperosmolality inhibits apical membrane
Na+/H+ exchange (NHE3) activity via a signaling pathway distinct from these MAP
kinase pathways.
PMID- 9755120
TI - Activation of H+-ATPase by hypotonicity: a novel regulatory mechanism for H+
secretion in IMCD cells.
AB - The effect of hypotonicity on H+-ATPase activity was examined in cultured inner
medullary collecting duct (mIMCD-3) cells. mIMCD-3 cells were grown to
confluence, loaded with 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein
(BCECF), and assayed for H+-ATPase activity measured as the Na+- and K+
independent intracellular pH (pHi) recovery following an acid load. Exposure of
mIMCD-3 cells to a hypotonic solution (150 mosmol/kgH2O) increased pHi recovery
by approximately 350% (P < 0.0001). This effect was inhibited by
diethylstilbestrol (an inhibitor of H+-ATPase) and was not dependent on external
K+, indicating lack of involvement of H+-K+-ATPase. H+-ATPase activation was
acute, independent of cell calcium, and was not secondary to Cl- channel
activation. The magnitude of H+-ATPase upregulation was dependent on the
osmolarity of the media, with maximum stimulation at 150 mosmol/kgH2O. H+-ATPase
upregulation in hypotonicity was significantly blocked in the presence of
staurosporine or calphostin C or in cells pretreated with phorbol 12-myristate 13
acetate (PMA), indicating involvement of protein kinase C. Hypotonicity inhibited
the Na+/H+ exchanger activity in mIMCD-3 cells, indicating that its stimulatory
effect is specific to H+-ATPase. In conclusion, a novel regulatory mechanism of
H+-ATPase by hypotonicity is described. The increased H+-ATPase activity in
hypotonicity may be responsible for increased HCO-3 reabsorption and maintained
acid-base homeostasis in hyposmolar states.
PMID- 9755121
TI - Bradykinin may be involved in neuropeptide Y-induced diuresis, natriuresis, and
calciuresis.
AB - Neuropeptide Y (NPY) can cause diuresis, natriuresis, and calciuresis in rats
independently of the pressure-natriuresis mechanism (A. Bischoff and M. C.
Michel. Pflugers Arch. 435: 443-453, 1998). Because this is seen in systemic but
not intrarenal NPY infusion, we have investigated the possible mediator of
tubular NPY effects in anesthetized rats. In the present study, infusion of NPY
(2 micrograms . kg-1 . min-1) enhanced renovascular resistance by approximately 8
mmHg . ml-1 . min and enhanced urine and sodium excretion by approximately 450
microliter/15 min and approximately 60-85 micromol/15 min, respectively. Acute
renal denervation did not alter renovascular or tubular NPY effects, indicating
that a neuronally released mediator is not involved. Treatment with the
angiotensin II-receptor antagonist losartan prevented the decline of the
renovascular response with time but did not modify tubular NPY effects. The
bradykinin B2-receptor antagonist icatibant accelerated the decline of the
renovascular NPY effects with time; concomitantly, it attenuated NPY-induced
diuresis and natriuresis and abolished NPY-induced calciuresis. The converting
enzyme inhibitor ramiprilat prevented the decline of the renovascular response
with time; concomitantly, it magnified the NPY-induced diuresis, natriuresis, and
calciuresis. We conclude that bradykinin may be involved in NPY-induced diuresis,
natriuresis, and, in particular, calciuresis.
PMID- 9755122
TI - Immunochemical characterization of Na+/H+ exchanger isoform NHE4.
AB - Mammalian Na+/H+ exchangers (NHEs) are a family of transport proteins (NHE1
NHE5). To date, the cellular and subcellular localization of NHE4 has not been
characterized using immunochemical techniques. We purified a fusion protein
containing a portion of rat NHE4 (amino acids 565-675) to use as immunogen. A
monoclonal antibody (11H11) was selected by ELISA. It reacted specifically with
both the fusion protein and to a 60- to 65-kDa polypeptide expressed in NHE4
transfected LAP1 cells. By Western blot analysis, NHE4 was identified as a 65- to
70-kDa protein that was expressed most abundantly in stomach and in multiple
additional epithelial and nonepithelial rat tissues including skeletal muscle,
heart, kidney, uterus, and liver. Subcellular localization of NHE4 in the kidney
was evaluated by Western blot analysis of membrane fractions isolated by Percoll
gradient centrifugation. NHE4 was found to cofractionate with the basolateral
markers NHE1 and Na+-K+-ATPase rather than the luminal marker gamma-glutamyl
transferase. In stomach, NHE4 was detected by immunoperoxidase labeling on the
basolateral membrane of cells at the base of the gastric gland. We conclude that
NHE4 is a 65- to 70-kDa protein with a broad tissue distribution. In two types of
epithelial cells, kidney and stomach, NHE4 is localized to the basolateral
membrane.
PMID- 9755123
TI - Inducible transcriptional activity of bcn-1 element from laminin gamma1-chain
gene promoter in renal and nonrenal cells.
AB - Laminin is a major component of the extracellular matrix whose expression is
regulated by growth factors. The laminin gamma1-chain promoter contains a newly
identified transcriptional element denoted bcn-1 that is both active and
inducible in mesangial cells. In this study, we explored activation of the bcn-1
element in other renal and nonrenal cells. Treatment of rat glomerular epithelial
cells (GEC) with phorbol 12-myristate 13-acetate (PMA) increased activity of the
bcn-1 transcriptional element, within the context of the native laminin gamma1
chain promoter or when cloned upstream of a heterologous promoter. Treatment of
GEC with PMA induced nuclear DNA-binding activity, BCN-1, which was recognized by
the bcn-1 motif in a gel shift assay. These results provide evidence that the bcn
1 motif and its cognate BCN-1 factor(s) may regulate transcription of the laminin
gamma1-chain in GEC. The bcn-1 element and its cognate BCN-1 DNA-binding activity
were also inducible in monkey kidney COS-7 and in human T cell Jurkat lines. SDS
PAGE of in situ ultraviolet cross-linked nucleoproteins from GEC, COS, and Jurkat
cells revealed one major 110-115 kDa adduct in all three cell lines. These
results demonstrate that the bcn-1 element is active in renal and nonrenal cells
from different mammalian species where the same protein contributes to the
inducible BCN-1 DNA-binding activity.
PMID- 9755124
TI - Differential expression, abundance, and regulation of Na+-phosphate cotransporter
genes in murine kidney.
AB - Three classes of high-affinity Na+-Pi cotransporters are expressed in mammalian
kidney. These include Npt1 (type I), Npt2 (type II), and the cellular receptors
for gibbon ape leukemia virus (Glvr-1) and amphotropic murine retrovirus (Ram-1)
(type III). We defined the tissue distribution as well as the relative renal
abundance of Npt1, Npt2, Glvr-1, and Ram-1 mRNAs and examined the effects of low
Pi diet, the Hyp mutation, and growth hormone (GH) on their renal expression by
ribonuclease protection assay. In normal mouse kidney, Npt1, Npt2, Glvr-1, and
Ram-1 accounted for 15 +/- 1.0, 84 +/- 1.0, 0.5 +/- 0.2, and 0.5 +/- 0.3% of
total Na+-Pi cotransporter mRNAs, respectively. Evidence was obtained for low
abundance Npt1 mRNA expression in liver and Npt2 mRNA expression in intestine,
whereas Glvr-1 and Ram-1 mRNAs were also detected in bone, intestine, heart, and
liver. Npt2 mRNA was localized to proximal tubules in the renal outer cortex,
whereas Glvr-1 transcripts were detected throughout the kidney by in situ
hybridization. The Hyp mutation elicited a significant reduction in renal Npt1
and Npt2 mRNAs (78 +/- 8 and 57 +/- 3% of normal, respectively), whereas neither
low-Pi diet nor GH influenced the renal abundance of Npt1 and Npt2 transcripts.
Renal Glvr-1 mRNA expression was significantly increased in Hyp mice and GH
treated mice (145 +/- 6 and 165 +/- 5% of control, respectively), whereas the
renal abundance of Ram-1 transcript was unaffected by either the Hyp mutation,
low-Pi diet, or GH treatment. In summary, we demonstrate that Npt2 is the
predominant Na+-Pi cotransporter in mouse kidney, that Npt2 and Glvr-1 have
distinct patterns of renal expression, and that the Hyp mutation modulates the
renal expression of Npt1, Npt2, and Glvr-1 mRNAs. Our results suggest that
increased renal Glvr-1 mRNA may contribute to GH stimulation of renal Na+-Pi
cotransport.
PMID- 9755125
TI - Characterization of angiotensin IV-degrading enzymes and receptors on rat
mesangial cells.
AB - Because mesangial cells (MC) are a target and a degradation site for angiotensin
II (ANG II), we characterized the degrading enzymes and receptors of ANG IV, a
metabolite of ANG II, on these cells. ANG IV was metabolized into its NH2
terminal deleted peptides, ANG II-(4-8), ANG II-(5-8), and ANG II-(6-8) by rat
MC. Total protection of ANG IV was obtained only when PC-18, a specific
aminopeptidase N (APN) inhibitor, and JFH-27A, a mixed inhibitor of
dipeptidylaminopeptidase (DAP) and neutral endopeptidase (NEP), were
simultaneously added. In contrast, thiorphan, an NEP inhibitor, was inactive.
These results demonstrate the exclusive role of APN and DAP in ANG IV
degradation. 125I-labeled ANG IV binding was studied in the presence of PC-18 and
JFH-27A to suppress ligand degradation. Under these conditions, ANG IV-specific
receptors could be demonstrated with a KD of 1.8 nM and a density of 55 fmol/mg.
In contrast with MC, no evidence for ANG IV receptors could be obtained in
freshly isolated glomeruli. ANG IV stimulated cytosolic calcium concentration in
MC, whereas its NH2-terminal deleted metabolites were inactive. Therefore, ANG IV
must be protected from degradation by APN and DAP in studies on the nonimmediate
biological effects of this peptide.
PMID- 9755126
TI - Dietary K+ restriction upregulates total and Sch-28080-sensitive bicarbonate
absorption in rat tIMCD.
AB - In tubules from the terminal segment of the inner medullary collecting duct
(tIMCD) from rats with chronic metabolic acidosis, our laboratory has shown that
bicarbonate absorption (JtCO2) is inhibited by removal of K+ from the luminal
fluid or by the addition of Sch-28080 to the perfusate. The present study asked
whether total and/or Sch-28080-sensitive JtCO2 is regulated by changes in
systemic K+ homeostasis. Rat tIMCD tubules were perfused in vitro in symmetrical,
HCO-3/CO2-buffered solutions containing 10 mM KCl + 6 mM NH4Cl. Total and Sch
28080-sensitive JtCO2 were measured in rats with varying K+ intake. In K+-replete
rats, baseline JtCO2 was 2.1 +/- 0.3 pmol . mm-1 . min-1 (n = 6). In rats fed a
K+-deficient diet for 3 days, JtCO2 was 5.4 +/- 0.7 pmol . mm-1 . min-1 (n = 16,
P < 0. 05). To determine the mechanism for the increase in HCO-3 absorption
observed with K+ restriction, the Sch-28080-sensitive component of JtCO2 was
measured in each treatment group. Following the addition of Sch-28080 (10 microM)
to the perfusate, a 40% reduction in JtCO2 was observed in K+-restricted rats.
JtCO2 was not reduced following the addition of Sch-28080 in rats with normal K+
intake. Because Sch-28080-sensitive JtCO2 was increased in K+-restricted rats,
Sch-28080-sensitive JtCO2 was studied further in tIMCD tubules from rats in this
treatment group. In K+-restricted rats, JtCO2 decreased by 20% following the
addition of 5 mM ouabain to the perfusate. This ouabain-induced decline in JtCO2
was observed both in the presence and in the absence of Sch-28080. We conclude
that total and Sch-28080-sensitive net acid secretion is increased with dietary
K+ restriction. However, since approximately 50% of JtCO2 is insensitive to both
Sch-28080 and ouabain, future studies will be necessary to define other
mechanisms of luminal acidification in the rat tIMCD.
PMID- 9755127
TI - Cloning, characterization, and gene organization of K-Cl cotransporter from pig
and human kidney and C. elegans.
AB - We isolated and characterized the cDNAs for the human, pig, and Caenorhabditis
elegans K-Cl cotransporters. The pig and human homologs are 94% identical and
contain 1,085 and 1,086 amino acids, respectively. The deduced protein of the C.
elegans K-Cl cotransporter clone (CE-KCC1) contains 1,003 amino acids. The
mammalian K-Cl cotransporters share approximately 45% similarity with CE-KCC1.
Hydropathy analyses of the three clones indicate typical KCC topology patterns
with 12 transmembrane segments, large extracellular loops between transmembrane
domains 5 and 6 (unique to KCC), and large COOH-terminal domains. Human KCC1 is
widely expressed among various tissues. This KCC1 gene spans 23 kb and is
organized in 24 exons, whereas the CE-KCC1 gene spans 3.5 kb and contains 10
exons. Transiently and stably transfected human embryonic kidney cells (HEK-293)
expressing the human, pig, and C. elegans K-Cl cotransporter fulfilled two (pig)
or five (human and C. elegans) criteria for increased expression of the K-Cl
cotransporter. The criteria employed were basal K-Cl cotransport; stimulation of
cotransport by swelling, N-ethylmaleimide, staurosporine, and reduced cell Mg
concentration; and secondary stimulation of Na-K-Cl cotransport.
PMID- 9755128
TI - Redistribution of Na+/H+ exchanger isoform NHE3 in proximal tubules induced by
acute and chronic hypertension.
AB - Redistribution of apical Na+/H+ exchangers (NHE) in the proximal tubules as a
plausible mechanism of pressure natriuresis was investigated with confocal
immunofluorescence microscopy in Sprague-Dawley rats (SD), spontaneously
hypertensive rats (SHR), and two-kidney, one-clip Goldblatt hypertensive rats
(GH). NHE isoform NHE3 was localized in the brush border of proximal tubules in
SD. Twenty minutes of induced acute hypertension (20-40 mmHg) resulted in a
pronounced redistribution of isoform NHE3 from the brush border into the base of
microvilli, where clathrin-coated pits were localized. Prehypertensive young SHR
(5 wk old, mean blood pressure 105 +/- 3 mmHg, n = 11) produced similar findings.
However, NHE3 was found to concentrate in the base of microvilli in adult SHR (12
wk old, mean blood pressure 134 +/- 6 mmHg, n = 12) and nonclipped kidneys of GH
(mean blood pressure 131 +/- 6 mmHg, n = 6). In clipped kidneys of GH, which were
not exposed to the hypertension because of the arterial clips, NHE3 was localized
on the brush border as in normal SD. No further redistribution of NHE3 was
detected in adult SHR or GH when acute hypertension was induced. Since both acute
and chronic increase of arterial pressure can provoke the redistribution of
apical NHE in proximal tubules, the pressure-induced NHE redistribution could be
a physiological response and an integral part of pressure natriuresis.
PMID- 9755129
TI - Effects of antihypertensive drugs on autoregulation of RBF and glomerular
capillary pressure in SHR.
AB - The relationship between systemic blood pressure and glomerular capillary
pressure (Pgc) in spontaneously hypertensive rats (SHR) during treatment with
antihypertensive drugs is still unclear. The effects of an angiotensin-converting
enzyme inhibitor (enalapril), two calcium channel antagonists (nifedipine and
verapamil), and an alpha1-receptor blocker (doxazosin) on renal blood flow (RBF)
autoregulation, Pgc, and renal segmental resistances were therefore studied in
SHR. Recordings of RBF autoregulation were done before and 30 min after
intravenous infusion of the different drugs, and Pgc was thereafter measured with
the stop-flow technique. When the mean arterial pressure (MAP) was reduced to
approximately 120 mmHg by infusions of doxazosin or enalapril, the lower pressure
limit of RBF autoregulation was reduced significantly. Nifedipine or verapamil
abolished RBF autoregulation. Doxazosin did not change Pgc (43.6 +/- 1.4 vs. 46.7
+/- 1.5 mmHg in controls, P > 0.5), enalapril lowered (41.3 +/- 0.8 mmHg, P <
0.01), and the calcium channel antagonists increased Pgc [53.7 +/- 1.4 mmHg
(nifedipine) and 54.8 +/- 1.2 mmHg (verapamil), P < 0.01]. When MAP was reduced
to approximately 85 mmHg by drugs, Pgc was reduced to 43.3 +/- 1.7 mmHg after
nifedipine (P > 0.2 vs. control), whereas Pgc after enalapril was 38.5 +/- 0.5
mmHg (P < 0.05 vs. control). Enalapril reduced Pgc mainly by reducing efferent
resistance. During treatment with calcium channel antagonists, Pgc became
strictly dependent on MAP. Monotherapy with nifedipine may increase Pgc and by
this mechanism accelerate glomerulosclerosis if a strict blood pressure control
is not obtained.
PMID- 9755130
TI - Inactivation of kinase cascades in mesangial cells grown on collagen type I.
AB - Growth on collagen type I gels is known to suppress the mitogenic responsiveness
of mesangial cells. Because these cells proliferate in some renal diseases and
themselves synthesize collagen type I, we examined the influence of growth on
collagen upon several kinase signaling cascades involved in mesangial cell
proliferation. Quiescent mesangial cells grown on collagen type I and then
stimulated with serum showed a markedly diminished induction of the protooncogene
c-fos, compared with their counterparts on plastic or fibronectin. This effect
was accompanied by decreased activation of mitogen-activated (Erk family) and
Ca2+/calmodulin-dependent protein kinases. Cells on collagen showed lower basal
protein kinase C (PKC) activity and diminished levels of PKC-alpha and -zeta
isoforms. Global phosphorylation of tyrosine residues was diminished on collagen,
and tyrosine phosphorylation of Erk and focal adhesion kinase in response to
serum was not detected, in contrast to cells on plastic. We conclude that
attachment of mesangial cells to collagen type I results in a broad suppression
of protein phosphorylation that is reflected in diminished induction of the c-fos
gene and probably underlies the conversion of cultured mesangial cells to a
nonproliferative phenotype.
PMID- 9755131
TI - Cyclosporin A increases hypoxia and free radical production in rat kidneys:
prevention by dietary glycine.
AB - The major side effect of cyclosporin A is severe nephrotoxicity. It is likely
that cyclosporin A causes vasoconstriction leading to hypoxia-reperfusion injury;
therefore, these experiments were designed to attempt to obtain physical evidence
for hypoxia and free radical production in kidney following cyclosporin A. Rats
were treated daily with cyclosporin A (25 mg/kg ig) for 5 days, and pimonidazole,
a hypoxia marker, was injected 2 h after the last dose of cyclosporin A. A dose
of alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) was injected 3 h after
cyclosporin A to trap free radicals. Cyclosporin A doubled serum creatinine and
decreased glomerular filtration rates by 65% as expected. Pimonidazole adduct
binding in the kidney was increased nearly threefold by cyclosporin A, providing
physical evidence for tissue hypoxia. Moreover, cyclosporin A increased 4
POBN/radical adducts nearly sixfold in the urine but did not alter levels in the
serum. Glycine, which causes vasodilatation and prevents cyclosporin A toxicity,
minimized hypoxia and blocked free radical production; however, it did not alter
cyclosporin A blood levels. These results demonstrate for the first time that
cyclosporin A causes hypoxia and increases production of a new free radical
species exclusively in the kidney. Therefore, it is concluded that cyclosporin A
causes renal injury by mechanisms involving hypoxia-reoxygenation, effects which
can be prevented effectively by dietary glycine.
PMID- 9755132
TI - Cyclooxygenase-2 participates in tubular flow-dependent afferent arteriolar tone:
interaction with neuronal NOS.
AB - To delineate the microvascular role of cyclooxygenase-2 (Cox-2) in modulating
tubuloglomerular feedback (TGF) signals and to determine its relationship to
neuronal nitric oxide synthase (nNOS), afferent (AA) and efferent (EA) arteriolar
diameters of rat kidneys were assessed using the blood-perfused juxtamedullary
nephron technique. The Cox-2 inhibitor NS-398 (10 microM) did not alter AA
diameters in untreated kidneys but significantly constricted AAs by 17.0 +/- 2.2%
in kidneys treated with 10 mM acetazolamide, which enhances TGF-mediated AA
constriction by increasing distal volume delivery. The NS-398-induced AA
constriction was prevented after interruption of distal delivery by transection
of the loops of Henle. The effect was selective for AAs since NS-398 did not
influence EAs of untreated or acetazolamide-treated kidneys. Pretreatment with
the nNOS inhibitor S-methyl-L-thiocitrulline (10 microM) prevented the NS-398
induced AA constriction observed during acetazolamide treatment. Although we
previously demonstrated that acetazolamide treatment enhanced AA constrictor
response to S-methyl-L-thiocitrulline, the enhancement by acetazolamide was
inhibited by pretreatment with 10 microM NS-398 (16.4 +/- 1.9 and 15. 0 +/- 0.5%
with and without acetazolamide, respectively, P > 0.05). These results indicate
that, during increased activation of TGF-dependent vasoconstrictor signals, Cox-2
generates vasodilatory metabolites in response to increased nNOS activity and
thus participates in the counteracting modulation of TGF-mediated AA
constriction.
PMID- 9755133
TI - Selective increase of cyclooxygenase-2 expression in a model of renal ablation.
AB - Previous studies have suggested a possible role for prostaglandins (PGs) in
mediating alterations in nephron structure and function ensuing after renal
ablation. Two isoforms of cyclooxygenase (COX) have been described: constitutive
(COX-1) and inducible (COX-2). We examined expression of these isoforms following
subtotal renal ablation (5/6 ablation, RA) in rats. In renal cortex, COX-2 mRNA
and immunoreactive protein (IP) increased progressively compared with sham
operated littermates. In contrast, there were no significant changes in COX-1
mRNA expression. In normal kidney, cortical COX-1 IP was immunolocalized
predominantly to mesangial cells and collecting tubules, whereas COX-2 IP was
found in a subset of cortical thick ascending limb of Henle's loop (CTAL) cells
in the region of the macula densa (MD). Following RA, significantly increased COX
2 IP was detected in the MD and surrounding CTAL cells. In addition, fainter
immunoreactive COX-2 was detected in scattered visceral epithelial cells and
mesangial cells of the glomerulus. Immunoblotting of isolated glomeruli
demonstrated a selective increase of glomerular immunoreactive COX-2 expression
following RA. No change of COX-1 expression was seen. To determine COX activity,
isolated glomeruli were incubated with arachidonic acid and PGE2 measured by
enzyme immunoassay (EIA). Compared with sham, glomeruli from 2 wk RA produced
significantly more PGs. SC-58560, a selective COX-1 inhibitor, did not inhibit PG
production in the remnant glomeruli at concentrations up to 10(-4) M, whereas SC
58236, a relatively selective COX-2 inhibitor, significantly inhibited PG
production by RA glomeruli. In preliminary studies, to define mechanisms of
altered expression of glomerular COX-2, rat mesangial cells were incubated with
serum from sham or 2 wk RA. There were significant increases in COX-2 expression
in response to 2 wk RA serum. In summary, these results indicate selective
increases in renal cortical COX-2 expression following renal ablation.
PMID- 9755134
TI - Size characteristics of larger academic human environmental health programs in
the United States.
AB - We have performed a benchmark exercise evaluating larger academic programs in
human environmental health sciences. These programs are located at schools of
public health and at other institutions that have NIEHS Centers of Excellence.
The largest programs were those in which there was both an NIEHS center and a
public health graduate education program. This suggests that there is synergy
between environmental health sciences research and involvement in public and
community health.
PMID- 9755135
TI - Update on national toxicology program (NTP) assays with genetically altered or
"transgenic" mice.
AB - The NTP is evaluating several lines of genetically altered mice for possible use
in identifying and assessing carcinogens. The NIEHS/NTP programs and progress in
this area were recently reviewed by the NTP Board of Scientific Counselors (BSC).
A number of comments and concerns were raised. This commentary summarizes and
responds to the BSC review and offers some thoughts on future directions for this
line of research as well as possible ways genetically altered mice might be
integrated into a comprehensive testing strategy.
PMID- 9755136
TI - Human exposure assessment and the National Toxicology Program.
AB - The National Institute of Environmental Health Sciences/National Toxicology
Program (NIEHS/NTP) is developing a new interagency initiative in exposure
assessment. This initiative involves the NIEHS, the Centers for Disease Control
and Prevention through its National Center for Environmental Health, the National
Institute for Occupational Safety and Health, the EPA, and other participating
institutes and agencies of the NTP. This initiative will benefit public health
and priority setting in a number of ways. First, as discussed above, it will
strengthen the scientific foundation for risk assessments by the development of
more credible exposure/response relationships in people by improving cross
species extrapolation, the development of biologically based dose-response
models, and the identification of sensitive subpopulations and for "margin of
exposure" based estimates of risk. Second, it will provide the kind of
information necessary for deciding which chemicals should be studied with the
limited resources available for toxicological testing. For example, there are
85,000 chemicals in commerce today, and the NTP can only provide toxicological
evaluations on 10-20 per year. Third, we would use the information obtained from
the exposure initiative to focus our research on mixtures that are actually
present in people's bodies. Fourth, we would obtain information on the kinds and
amount of chemicals in children and other potentially sensitive subpopulations.
Determinations of whether additional safety factors need to be applied to
children must rest, in part, upon comparative exposure analyses between children
and adults. Fifth, this initiative, taken together with the environmental genome
initiative, will provide the science base essential for meaningful studies on
gene/environment interactions, particularly for strengthening the evaluation of
epidemiology studies. Sixth, efficacy of public health policies aimed at reducing
human exposure to chemical agents could be evaluated in a more meaningful way if
body burden data were available over time, including remediation around Superfund
sites and efforts to achieve environmental justice. The exposure assessment
initiative is needed to address public health needs. It is feasible because of
recent advances in analytical technology and molecular biology, and it is an
example of how different agencies can work together to better fulfill their
respective missions.
PMID- 9755137
TI - New findings on sources and biokinetics of lead in human breast milk: bone lead
can target both nursing infant and fetus.
PMID- 9755138
TI - Cytochromes P450 and species differences in xenobiotic metabolism and activation
of carcinogen.
AB - The importance of cytochrome P450 isoforms to species differences in the
metabolism of foreign compounds and activation of procarcinogens has been
identified. The possible range of P450 isozymes in significant variations in
toxicity exhibited by experimental rodent species may have a relevance to
chemical risk assessment, especially as human P450s are likely to show changes in
the way they metabolize xenobiotics. Consequently, in the safety evaluation of
chemicals, we should be cautious in extrapolating results from experimental
animal models to humans. This paper focuses on examples in which species
differences in P450s lead to significant alterations in carcinogenic response,
and includes a discussion of the current procedures for toxicity screening, with
an emphasis on short-term tests.
PMID- 9755139
TI - Effect of NOx on the somatic chromosomes of goldsmiths.
AB - The genotoxic effect of NOx was investigated on somatic human chromosomes
obtained from lymphocytes of 45 goldsmiths exposed to 1770.5 mg/m3 NOx in ambient
air at normal temperature and pressure and compared to an equal number of matched
controls breathing air containing 50 microgram/m3 NOx. Short-term lymphocyte
cultures were set up from blood collected from both exposed and control
individuals by venipuncture in heparinized sterile syringes. Mitotic index (MI),
chromosome aberrations (CAs), sister chromatid exchanges (SCEs), and satellite
associations (SAs) were analyzed. All the parameters showed a significant
increase (p<0.01 and p<0.05) in the exposed individuals as compared to the
controls: MI (9.57 vs. 5.01), CAs (3. 48 vs. 0.711), SCEs (10.56 vs. 7.02), and
SAs (25.97 vs. 12.84), respectively. Occurrence of DG-type SAs (one D-group
chromosome and one G-group chromosome) was highest and 3 D-type (three D-group
chromosomes) lowest. NOx was thus found to be genotoxic for humans.
PMID- 9755140
TI - Carbon monoxide and hospital admissions for congestive heart failure: evidence of
an increased effect at low temperatures.
AB - The combined effects of carbon monoxide and low temperature on daily variation in
hospital admissions for congestive heart failure (CHF) were examined for a 4-year
period in Chicago, Illinois. Medicare hospital admissions for CHF were analyzed
as a function of the maximum hourly temperature, maximum hourly levels of carbon
monoxide (CO), and other criteria pollutants in Chicago for each day of the 4
year period (1986-1989). The regression analyses for the time series were
conducted using single and multipollutant models with interaction terms and
adjustments for weather, weekly cycles, seasonal effects, and secular trend. The
data were also grouped into three temperature ranges, <40 degrees, 40 degrees-75
degrees, and >75 degrees F, and the relationship between CO and CHF admissions
was evaluated for each range. For the 4-year time series, the CO level was
positively associated with hospital admissions for CHF in the single pollutant
and multipollutant models after adjustment for seasonal effects and weather
pattern. The relative risks of hospital admissions for CHF in Chicago associated
with the 75th percentile of exposure to CO in the high, medium, and low
temperature ranges were 1.02 [95% confidence interval (CI), 0.95-1.10], 1.09 (CI,
1.04-1.14), and 1.15 (CI, 1.09-1.22), respectively. In these data, the effect of
CO on hospital admissions for CHF was temperature dependent, with the magnitude
of the effect increasing with decreasing temperature. This synergy may help to
explain the association between ambient CO and CHF admissions demonstrated in
other studies.
PMID- 9755142
TI - Variability of house dust mite allergen exposure in dwellings.
AB - The variability of repeated house dust mite (HDM) allergen determinations at the
same site within 3-24 months was evaluated on previously collected samples.
Between two and four repeated measurements of Der p 1, a major allergen of
Dermatophagoides pteronyssinus and Der f 1, a major allergen of D. farinae, on 46
carpets and 31 mattresses were analyzed. In 90% of carpets and mattresses, HDM
allergen concentrations were clinically relevant (at least one measurement >0.1
microg Der p 1 + Der f 1/g dust). The coefficients of variation (CVs) for
allergen concentrations in repeated samples over time (55.3-82.0% for the two
allergens in beds and carpets) were clearly greater than the CVs for multiple
samples collected at the same time (4.0-32.6%). Determination of allergen mass
per square meter of surface instead of concentration per gram of dust resulted in
an even greater CV (72.3-86.7%). The 95% range of expected values was about 10
fold above and below the result of a single determination. We conclude that
single determinations of HDM allergen in dust give very limited information about
long-term exposure of an individual to the allergen. Repeated measurements are
recommended. Studies of factors that affect HDM allergen exposure must be planned
with appropriate sample sizes.
PMID- 9755141
TI - Prevalence of elevated blood lead levels in an inner-city pediatric clinic
population.
AB - In November 1997, the Centers for Disease Control and Prevention (CDC) released
revised guidelines for lead poisoning screening, including a recommendation that
states and regions individualize screening policies based on local prevalence of
elevated lead levels. The purpose of this study was to collect prevalence data
for a Philadelphia, Pennsylvania, inner-city pediatric outpatient population
previously not known to have elevated blood lead levels in order to determine its
risk for lead exposure and screening requirements. Charts were reviewed for 817
children of 10 months through 6 years of age whose venous blood lead levels were
obtained as part of their routine health care over a 12-month period ending
October 1992. None of these children had a history of previously elevated lead
levels. Prevalence of elevated lead levels was determined for this population and
correlated with patient age, sex, race, and insurance type. More than two-thirds
(68%) of the study patients had a blood lead level of [Greater than and equal
to]10 microg/dl. Elevated blood lead levels were associated with black race
(p<0.0001), but not with sex or insurance type. The percentage of children with
elevated blood lead levels was highest at ages 37-48 months. A majority of the
children screened had lead levels in excess of the CDC threshold for an abnormal
lead level (10 microgram/dl). This is the highest reported prevalence within a
U.S. pediatric clinic population. In view of this extremely high prevalence,
clinicians and public health personnel caring for children in Philadelphia inner
city clinics must follow the intent of the new CDC guidelines by increasing their
efforts in the areas of screening, follow-up, and environmental interventions. To
ensure a lead-safe upbringing for children in the United States, state health
officials nationwide should perform local risk assessments before considering
policy transitions from universal to targeted screening.
PMID- 9755143
TI - Antibodies to toluene diisocyanate in an environmentally exposed population.
AB - Residents living near a polyurethane foam manufacturing facility expressed
concern to health officials over chemical emissions from the plant. Environmental
monitoring of ambient air near the plant indicated the presence of toluene
diisocyanate (TDI), which was used in foam production. Health officials collected
blood samples from 113 residents and analyzed the blood sera for antibodies to
TDI and related diisocyanates. Ten of the 113 residents (9%) had elevated levels
of IgG or IgE antibodies specific for one or more diisocyanates. Exposure
histories were taken from antibody-positive individuals to identify possible
occupational exposure to TDI or the use of diisocyanate-containing consumer
products. Exposure to TDI in ambient air may be responsible for the positive
antibody responses detected in some residents of the community.
PMID- 9755144
TI - Relationships of lead in breast milk to lead in blood, urine, and diet of the
infant and mother.
AB - We have obtained stable lead isotope and lead concentration data from a
longitudinal study of mobilization of lead from the maternal skeleton during
pregnancy and lactation and in which the newly born infants were monitored for 6
months postpartum to evaluate the effects of the local environment on lead body
burden of the infant. Samples of maternal and infant blood, urine, and diet and
especially breast milk were measured for 21 mothers and 24 infants. Blood lead
concentrations were less than 5 microg/dl in all except one subject. The mean
lead concentration in breast milk +/- standard deviation was 0.73 +/- 0.70
microg/kg. In seven subjects for whom serial breast milk sampling was possible,
the lead concentration varied by factors of from 2 to 4, and for three subjects
there was an increase at or after 90 days postpartum. For the first 60-90 days
postpartum, the contribution from breast milk to blood lead in the infants varied
from 36 to 80%. Multiple linear regression analyses indicated statistically
significant relationships for some of the variables of isotope ratios and lead
concentrations between breast milk, blood, urine, and diet for infants and
mothers. For example, the analyses revealed that both a mother's breast milk
207Pb/206Pb and 206Pb/204Pb ratios and lead concentration provide information to
predict her infant's blood 207Pb/206Pb and 206Pb/204Pb ratios. The major sources
of lead in breast milk are from the maternal bone and diet. An evaluation of
breast milk lead concentrations published over the last 15 years indicates that
studies in which the ratio of lead concentrations in breast milk to lead
concentrations in whole maternal blood (Multiple>100) were greater than 15 should
be viewed with caution because of potential contamination during sampling and/or
laboratory analyses. Selected studies also appear to show a linear relationship
between breast milk and maternal whole blood, with the percentage of lead in
breast milk compared with whole blood of <3% in subjects with blood lead levels
ranging from 2 to 34 microgram/dl. The levels of lead in breast milk are thus
similar to those in plasma. Breast-fed infants are only at risk if the mother is
exposed to high concentrations of contaminants either from endogenous sources
such as the skeleton or exogenous sources.
PMID- 9755145
TI - Chlorinated hydrocarbons in women with repeated miscarriages.
AB - This study was conducted to investigate a possible etiological role of
chlorinated hydrocarbons in the pathogenesis of repeated miscarriages. The blood
levels of chlorinated hydrocarbons [CHCs: pentachlorophenol,
hexachlorocyclohexane, hexachlorobenzene, the dichlorodiphenyltrichloroethane
(DDT) group, polychlorinated biphenyls] were determined in 89 women with repeated
miscarriages, who were referred to the University Hospital of Obstetrics and
Gynecology of Heidelberg for investigations between 1989 and 1993, and compared
to a previously investigated reference population. In more than 20% of the women,
at least one of the CHC levels exceeded the reference range. CHC levels did not
differ significantly between women with primary or secondary and early or late
miscarriages; neither did they differ between women with hormonal or
immunological disorders as causes of repeated miscarriages or women with
idiopathic repeated miscarriages. No significant associations were detected
between CHC levels and further conceptions or the outcome of further pregnancies.
As significant associations were found between increasing CHC blood
concentrations and immunological and hormonal changes, CHCs may have an impact on
the pregnancy course in certain cases.
PMID- 9755146
TI - Public health policy and the National Toxicology Program.
PMID- 9755147
TI - Re: the use of offspring sex ratios in the search for endocrine disruptors.
PMID- 9755148
TI - New NTP centers meet the need to know.
PMID- 9755149
TI - 20 years of toxicology.
AB - With over 80,000 chemicals being used in commerce worldwide, it is important to
identify the human health effects of these chemicals and the levels of exposure
at which they are harmful to humans. In order to address this need, the National
Toxicology Program (NTP) was established in 1978; since then, the NTP has become
the world's leader in designing, conducting, and interpreting various types of
toxicity assays.
PMID- 9755150
TI - New tricks for an old assay.
AB - For decades, a number of guinea pig tests have been used to identify human
contact allergens in workplace and consumer products, but these tests have
limitations. In addition to using large numbers of test animals, they also
provide only subjective measurements, because the allergic activity is measured
by watching the skin for redness. Furthermore, coloring in some chemicals that
are evaluated may mask reddening of the skin, thus obscuring the results. Since
the 1980s, investigators have sought alternative test methods that would reduce
the number of animals required and address the limitations of current tests.
PMID- 9755151
TI - Trinucleotide expansion diseases in the context of micro- and minisatellite
evolution, Hammersmith Hospital, April 1-3, 1998.
PMID- 9755152
TI - DNA damage checkpoint in budding yeast.
AB - Eukaryotic cells have evolved a network of control mechanisms, known as
checkpoints, which coordinate cell-cycle progression in response to internal and
external cues. The yeast Saccharomyces cerevisiae has been invaluable in
dissecting genetically the DNA damage checkpoint pathway. Recent results on
posttranslational modifications and protein-protein interactions of some key
factors provide new insights into the architecture of checkpoint protein
complexes and their order of function.
PMID- 9755153
TI - Potassium channel openers require ATP to bind to and act through sulfonylurea
receptors.
AB - KATP channels are composed of a small inwardly rectifying K+ channel subunit,
either KIR6.1 or KIR6.2, plus a sulfonylurea receptor, SUR1 or SUR2 (A or B),
which belong to the ATP-binding cassette superfamily. SUR1/KIR6.2 reconstitute
the neuronal/pancreatic beta-cell channel, whereas SUR2A/KIR6.2 and SUR2B/KIR6.1
(or KIR6.2) are proposed to reconstitute the cardiac and the vascular-smooth
muscle-type KATP channels, respectively. We report that potassium channel openers
(KCOs) bind to and act through SURs and that binding to SUR1, SUR2A and SUR2B
requires ATP. Non-hydrolysable ATP-analogues do not support binding, and Mg2+ or
Mn2+ are required. Point mutations in the Walker A motifs or linker regions of
both nucleotide-binding folds (NBFs) abolish or weaken [3H]P1075 binding to
SUR2B, rendering reconstituted SUR2B/KIR6.2 channels insensitive towards KCOs.
The C-terminus of SUR affects KCO affinity with SUR2B approximately SUR1 > SUR2A.
KCOs belonging to different structural classes inhibited specific [3H]P1075
binding to SUR2B in a monophasic manner, with the exception of minoxidil sulfate,
which induced a biphasic displacement. The affinities of KCO binding to SUR2B
were 3.5-8-fold higher than their potencies for activation of SUR2B/KIR6.2
channels. The results establish that SURs are the KCO receptors of KATP channels
and suggest that KCO binding requires a conformational change induced by ATP
hydrolysis in both NBFs.
PMID- 9755154
TI - Importance of a flexible hinge near the motor domain in kinesin-driven motility.
AB - Conventional kinesin is a molecular motor consisting of an N-terminal catalytic
motor domain, an extended stalk and a small globular C-terminus. Whereas the
structure and function of the catalytic motor domain has been investigated,
little is known about the function of domains outside the globular head. A short
coiled-coil region adjacent to the motor domain, termed the neck, is known to be
important for dimerization and may be required for kinesin processivity. We now
provide evidence that a helix-disrupting hinge region (hinge 1) that separates
the neck from the first extended coiled-coil of the stalk plays an essential role
in basic motor activity. A fast fungal kinesin from Syncephalastrum racemosum was
used for these studies. Deletion, substitution by a coiled-coil and truncation of
the hinge 1 region all reduce motor speed and uncouple ATP turnover from gliding
velocity. Insertion of hinge 1 regions from two conventional kinesins, Nkin and
DmKHC, fully restores motor activity, whereas insertion of putative flexible
linkers of other proteins does not, suggesting that hinge 1 regions of
conventional kinesins can functionally replace each other. We suggest that this
region is essential for kinesin movement in its promotion of chemo-mechanical
coupling of the two heads and therefore the functional motor domain should be
redefined to include not only the catalytic head but also the adjacent neck and
hinge 1 domains.
PMID- 9755155
TI - Disulfide bond formation in the Escherichia coli cytoplasm: an in vivo role
reversal for the thioredoxins.
AB - Cytoplasmic proteins do not generally contain structural disulfide bonds,
although certain cytoplasmic enzymes form such bonds as part of their catalytic
cycles. The disulfide bonds in these latter enzymes are reduced in Escherichia
coli by two systems; the thioredoxin pathway and the glutathione/glutaredoxin
pathway. However, structural disulfide bonds can form in proteins in the
cytoplasm when the gene (trxB) for the enzyme thioredoxin reductase is
inactivated by mutation. This disulfide bond formation can be detected by
assessing the state of the normally periplasmic enzyme alkaline phosphatase (AP)
when it is localized to the cytoplasm. Here we show that the formation of
disulfide bonds in cytoplasmic AP in the trxB mutant is dependent on the presence
of two thioredoxins in the cell, thioredoxins 1 and 2, the products of the genes
trxA and trxC, respectively. Our evidence supports a model in which the oxidized
forms of these thioredoxins directly catalyze disulfide bond formation in
cytoplasmic AP, a reversal of their normal role. In addition, we show that the
recently discovered thioredoxin 2 can perform many of the roles of thioredoxin 1
in vivo, and thus is able to reduce certain essential cytoplasmic enzymes. Our
results suggest that the three most effective cytoplasmic disulfide-reducing
proteins are thioredoxin 1, thioredoxin 2 and glutaredoxin 1; expression of any
one of these is sufficient to support aerobic growth. Our results help to explain
how the reducing environment in the cytoplasm is maintained so that disulfide
bonds do not normally occur.
PMID- 9755156
TI - The crystal structure of the processive endocellulase CelF of Clostridium
cellulolyticum in complex with a thiooligosaccharide inhibitor at 2.0 A
resolution.
AB - The mesophilic bacterium Clostridium cellulolyticum exports multienzyme complexes
called cellulosomes to digest cellulose. One of the three major components of the
cellulosome is the processive endocellulase CelF. The crystal structure of the
catalytic domain of CelF in complex with two molecules of a thiooligosaccharide
inhibitor was determined at 2.0 A resolution. This is the first three-dimensional
structure to be solved of a member of the family 48 glycosyl hydrolases. The
structure consists of an (alpha alpha)6-helix barrel with long loops on the N
terminal side of the inner helices, which form a tunnel, and an open cleft region
covering one side of the barrel. One inhibitor molecule is enclosed in the
tunnel, the other exposed in the open cleft. The active centre is located in a
depression at the junction of the cleft and tunnel regions. Glu55 is the proposed
proton donor in the cleavage reaction, while the corresponding base is proposed
to be either Glu44 or Asp230. The orientation of the reducing ends of the
inhibitor molecules together with the chain translation through the tunnel in the
direction of the active centre indicates that CelF cleaves processively
cellobiose from the reducing to the non-reducing end of the cellulose chain.
PMID- 9755157
TI - A plasma membrane-bound putative endo-1,4-beta-D-glucanase is required for normal
wall assembly and cell elongation in Arabidopsis.
AB - Endo-1,4-beta-D-glucanases (EGases) form a large family of hydrolytic enzymes in
prokaryotes and eukaryotes. In higher plants, potential substrates in vivo are
xyloglucan and non-crystalline cellulose in the cell wall. Gene expression
patterns suggest a role for EGases in various developmental processes such as
leaf abscission, fruit ripening and cell expansion. Using Arabidopsis thaliana
genetics, we demonstrate the requirement of a specialized member of the EGase
family for the correct assembly of the walls of elongating cells. KORRIGAN (KOR)
is identified by an extreme dwarf mutant with pronounced architectural
alterations in the primary cell wall. The KOR gene was isolated and encodes a
membrane-anchored member of the EGase family, which is highly conserved between
mono- and dicotyledonous plants. KOR is located primarily in the plasma membrane
and presumably acts at the plasma membrane-cell wall interface. KOR mRNA was
found in all organs examined, and in the developing dark-grown hypocotyl, mRNA
levels were correlated with rapid cell elongation. Among plant growth factors
involved in the control of hypocotyl elongation (auxin, gibberellins and
ethylene) none significantly influenced KOR-mRNA levels. However, reduced KOR
mRNA levels were observed in det2, a mutant deficient for brassinosteroids.
Although the in vivo substrate remains to be determined, the mutant phenotype is
consistent with a central role for KOR in the assembly of the cellulose
hemicellulose network in the expanding cell wall.
PMID- 9755158
TI - Functional dissection of Arabidopsis COP1 reveals specific roles of its three
structural modules in light control of seedling development.
AB - Arabidopsis COP1 acts as a repressor of photomorphogenesis in darkness, and light
stimuli abrogate the repressive ability and nuclear abundance of COP1. COP1 has
three known structural modules: an N-terminal RING-finger, followed by a
predicted coiled-coil and C-terminal WD-40 repeats. A systematic study was
undertaken to dissect the functional roles of these three COP1 domains in light
control of Arabidopsis seedling development. Our data suggest that COP1 acts
primarily as a homodimer, and probably dimerizes through the coiled-coil domain.
The RING-finger and the coiled-coil domains can function independently as light
responsive modules mediating the light-controlled nucleocytoplasmic partitioning
of COP1. The C-terminal WD-40 domain functions as an autonomous repressor module
since the overexpression of COP1 mutant proteins with intact WD-40 repeats are
able to suppress photomorphogenic development. This WD-40 domain-mediated
repression can be at least in part accounted for by COP1's direct interaction
with and negative regulation of HY5, a bZIP transcription factor that positively
regulates photomorphogenesis. However, COP1 self-association is a prerequisite
for the observed interaction of the COP1 WD-40 repeats with HY5. This work thus
provides a structural basis of COP1 as a molecular switch.
PMID- 9755159
TI - Coexpression of IL-6 and soluble IL-6R causes nodular regenerative hyperplasia
and adenomas of the liver.
AB - Studies with tumor necrosis factor p55 receptor- and interleukin-6 (IL-6)
deficient mice have shown that IL-6 is required for hepatocyte proliferation and
reconstitution of the liver mass after partial hepatectomy. The biological
activities of IL-6 are potentiated when this cytokine binds soluble forms of its
specific receptor subunit (sIL-6R) and the resulting complex interacts with the
transmembrane signaling chain gp130. We show here that double transgenic mice
expressing high levels of both human IL-6 and sIL-6R under the control of liver
specific promoters spontaneously develop nodules of hepatocellular hyperplasia
around periportal spaces and present signs of sustained hepatocyte proliferation.
The resulting picture is identical to that of human nodular regenerative
hyperplasia, a condition frequently associated with immunological and
myeloproliferative disorders. In high expressors, hyperplastic lesions progress
with time into discrete liver adenomas. These data strongly suggest that the IL
6/sIL-6R complex is both a primary stimulus to hepatocyte proliferation and a
pathogenic factor of hepatocellular transformation.
PMID- 9755160
TI - alphaKAP is an anchoring protein for a novel CaM kinase II isoform in skeletal
muscle.
AB - Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) is present in a
membrane-bound form that phosphorylates synapsin I on neuronal synaptic vesicles
and the ryanodine receptor at skeletal muscle sarcoplasmic reticulum (SR), but it
is unclear how this soluble enzyme is targeted to membranes. We demonstrate that
alphaKAP, a non-kinase protein encoded by a gene within the gene of alpha-CaM
kinase II, can target the CaM kinase II holoenzyme to the SR membrane. Our
results indicate that alphaKAP (i) is anchored to the membrane via its N-terminal
hydrophobic domain, (ii) can co-assemble with catalytically competent CaM kinase
II isoforms and target them to the membrane regardless of their state of
activation, and (iii) is co-localized and associated with rat skeletal muscle CaM
kinase II in vivo. alphaKAP is therefore the first demonstrated anchoring protein
for CaM kinase II. CaM kinase II assembled with alphaKAP retains normal enzymatic
activity and the ability to become Ca2+-independent following
autophosphorylation. A new variant of beta-CaM kinase II, termed betaM-CaM kinase
II, is one of the predominant CaM kinase II isoforms associated with alphaKAP in
skeletal muscle SR.
PMID- 9755161
TI - Regulated nucleo/cytoplasmic exchange of HOG1 MAPK requires the importin beta
homologs NMD5 and XPO1.
AB - MAP kinase signaling modules serve to transduce extracellular signals to the
nucleus of eukaryotic cells, but little is known about how signals cross the
nuclear envelope. Exposure of yeast cells to increases in extracellular
osmolarity activates the HOG1 MAP kinase cascade, which is composed of three
tiers of protein kinases, namely the SSK2, SSK22 and STE11 MAPKKKs, the PBS2
MAPKK, and the HOG1 MAPK. Using green fluorescent protein (GFP) fusions of these
kinases, we found that HOG1, PBS2 and STE11 localize to the cytoplasm of
unstressed cells. Following osmotic stress, HOG1, but neither PBS2 nor STE11,
translocates into the nucleus. HOG1 translocation occurs very rapidly, is
transient, and correlates with the phosphorylation and activation of the MAP
kinase by its MAPKK. HOG1 phosphorylation is necessary and sufficient for nuclear
translocation, because a catalytically inactive kinase when phosphorylated is
translocated to the nucleus as efficiently as the wild-type. Nuclear import of
the MAPK under stress conditions requires the activity of the small GTP binding
protein Ran-GSP1, but not the NLS-binding importin alpha/beta heterodimer.
Rather, HOG1 import requires the activity of a gene, NMD5, that encodes a novel
importin beta homolog. Similarly, export of dephosphorylated HOG1 from the
nucleus requires the activity of the NES receptor XPO1/CRM1. Our findings define
the requirements for the regulated nuclear transport of a stress-activated MAP
kinase.
PMID- 9755162
TI - Stress-activated protein kinases are negatively regulated by cell density.
AB - Stimulation by UV irradiation, TNFalpha, as well as PDGF or EGF activates the
JNK/SAPK signalling pathway in mouse fibroblasts. This results in the
phosphorylation of the N-terminal domain of c-Jun, increasing its transactivation
potency. Using an antibody that specifically recognizes c-Jun phosphorylated at
Ser63, we show that culture confluency drastically inhibited c-Jun N-terminal
phosphorylation due to the inhibition of the JNK/SAPK pathway. Transfection
experiments demonstrate that the inhibition occurs at the same level as, or
upstream of, the small G-proteins cdc42 and Rac1. In contrast, the classical MAPK
pathway was insensitive to confluency. The inhibition of JNK/SAPK activation
depended on the integrity of the actin microfilament network. These results were
confirmed and extended in monolayer wounding experiments. After PDGF, EGF or UV
stimulation, c-Jun was predominantly phosphorylated in cells bordering the wound,
which are the cells that move to occupy the wounded area. Thus, modulation of the
stress-dependent signal cascade by confluency will restrict c-Jun N-terminal
phosphorylation in response to mitogenic or chemotactic agents to cells that
border a wounded area.
PMID- 9755163
TI - The kinase Eg2 is a component of the Xenopus oocyte progesterone-activated
signaling pathway.
AB - Quiescent Xenopus oocytes are activated by progesterone, which binds to an
unidentified surface-associated receptor. Progesterone activates a poorly
understood signaling pathway that results in the translational activation of mRNA
encoding Mos, a MAP kinase kinase kinase necessary for the activation of MAP
kinase and MPF, the resumption of meiosis, and maturation of the oocyte into the
sperm-responsive egg. We have designed a screen to identify early signaling
proteins based on the premise that some of these proteins would be phosphorylated
or otherwise modified within minutes of progesterone addition. This screen has
revealed Eg2, a Ser/Thr kinase. We find that Eg2 is phosphorylated soon after
progesterone stimulation and provide evidence that it functions in the signaling
pathway. Overexpression of Eg2 via mRNA microinjection shortens the time between
progesterone stimulation and the appearance of new Mos protein, accelerates
activation of MAP kinase and advances entry into the meiotic cell cycle. Finally,
overexpression of Eg2 dramatically reduces the concentration of progesterone
needed to trigger oocyte activation. These results argue that the kinase Eg2 is a
component of the progesterone-activated signaling pathway that releases frog
oocytes from cell cycle arrest.
PMID- 9755164
TI - Tec/Bmx non-receptor tyrosine kinases are involved in regulation of Rho and serum
response factor by Galpha12/13.
AB - A transient transfection system was used to identify regulators and effectors for
Tec and Bmx, members of the Tec non-receptor tyrosine kinase family. We found
that Tec and Bmx activate serum response factor (SRF), in synergy with
constitutively active alpha subunits of the G12 family of GTP-binding proteins,
in transiently transfected NIH 3T3 cells. The SRF activation is sensitive to C3,
suggesting the involvement of Rho. The kinase and Tec homology (TH) domains of
the kinases are required for SRF activation. In addition, kinase-deficient
mutants of Bmx are able to inhibit Galpha13- and Galpha12-induced SRF activation,
and to suppress thrombin-induced SRF activation in cells lacking Galphaq/11,
where thrombin's effect is mediated by G12/13 proteins. Moreover, expression of
Galpha12 and Galpha13 stimulates autophosphorylation and transphosphorylation
activities of Tec. Thus, the evidence indicates that Tec kinases are involved in
Galpha12/13-induced, Rho-mediated activation of SRF. Furthermore, Src, which was
previously shown to activate kinase activities of Tec kinases, activates SRF
predominantly in Rho-independent pathways in 3T3 cells, as shown by the fact that
C3 did not block Src-mediated SRF activation. However, the Rho-dependent pathway
becomes significant when Tec is overexpressed.
PMID- 9755165
TI - A Nck-Pak1 signaling module is required for T-cell receptor-mediated activation
of NFAT, but not of JNK.
AB - The T-cell antigen receptor (TCR) triggers a signaling cascade initiated by the
tyrosine kinase Lck and requiring the proto-oncogene p95(vav). Vav is activated
by Lck and can function as a guanine nucleotide exchange factor for the Rho
family GTPases, Rac1 and Cdc42. To investigate the involvement of these GTPases
in TCR signaling, we focused on their well characterized effector, Pak1. This
serine/threonine kinase is activated by GTP-bound Rac1 or Cdc42. However, its
role in mediating downstream signaling events is controversial. We observed
rapid, TCR-dependent activation of Pak1 and TCR-inducible association of Pak1
with Nck, which was tyrosine phosphorylated following stimulation. Pak1
activation occurred independently of Ras activation or calcium flux, but was
dependent on the Lck tyrosine kinase, and was downstream of Vav and Cdc42.
Dominant negative Pak1 or Nck specifically inhibited TCR-mediated activation of
the nuclear factor of activated T cells (NFAT) transcription factor. TCR-mediated
activation of Erk2 was also inhibited by dominant negative Pak. However, Pak1
activation was neither necessary nor sufficient for TCR-dependent c-Jun N
terminal kinase (JNK) activation. Therefore, Pak1 acts downstream of Vav and is
required for activation of Erk2 and NFAT by a JNK-independent pathway. This is
the first demonstration of a requirement for Pak to mediate the regulation of
gene expression by an extracellular ligand.
PMID- 9755166
TI - An essential protease involved in bacterial cell-cycle control.
AB - Proteolytic inactivation of key regulatory proteins is essential in eukaryotic
cell-cycle control. We have identified a protease in the eubacterium Caulobacter
crescentus that is indispensable for viability and cell-cycle progression,
indicating that proteolysis is also involved in controlling the bacterial cell
cycle. Mutants of Caulobacter that lack the ATP-dependent serine protease ClpXP
are arrested in the cell cycle before the initiation of chromosome replication
and are blocked in the cell division process. ClpXP is composed of two types of
polypeptides, the ClpX ATPase and the ClpP peptidase. Site-directed mutagenesis
of the catalytically active serine residue of ClpP confirmed that the proteolytic
activity of ClpXP is essential. Analysis of mutants lacking ClpX or ClpP revealed
that both proteins are required in vivo for the cell-cycle-dependent degradation
of the regulatory protein CtrA. CtrA is a member of the response regulator family
of two-component signal transduction systems and controls multiple cell-cycle
processes in Caulobacter. In particular, CtrA negatively controls DNA replication
and our findings suggest that specific degradation of the CtrA protein by the
ClpXP protease contributes to G1-to-S transition in this organism.
PMID- 9755167
TI - The role of the destruction box and its neighbouring lysine residues in cyclin B
for anaphase ubiquitin-dependent proteolysis in fission yeast: defining the D-box
receptor.
AB - Programmed proteolysis of proteins such as mitotic cyclins and Cut2/Pds1p
requires a 9-residue conserved motif known as the destruction box (D-box). Strong
expression of protein fragments containing destruction boxes, such as the first
70 residues of Cdc13 (N70), inhibits the growth of Schizosaccharomyces pombe at
metaphase. This inhibition can be overcome either by removal of all lysine
residues from N70 using site-directed mutagenesis (K0-N70) or by raising the
concentration of intracellular ubiquitin. Consistent with the idea that
competition for ubiquitin accounts for some of its inhibitory effects, wild-type
N70 not only stabilized D-box proteins, but also Rum1 and Cdc18, which are
degraded by a different pathway. The K0-N70 construct was neither
polyubiquitinated nor degraded in vitro, but it blocked the growth of strains of
yeast in which anaphase-promoting complex/cyclosome (APC/C) function was
compromised by mutation, and specifically inhibited proteolysis of APC/C
substrates in vivo. Both K0-N70 and 20-residue D-box peptides blocked
polyubiquitination of other D-box-containing substrates in a cell-free
ubiquitination assay system. These data suggest the existence of a D-box receptor
protein that recognizes D-boxes prior to ubiquitination.
PMID- 9755168
TI - The budding yeast Rad9 checkpoint protein is subjected to Mec1/Tel1-dependent
hyperphosphorylation and interacts with Rad53 after DNA damage.
AB - The Saccharomyces cerevisiae RAD9 checkpoint gene is required for transient cell
cycle arrests and transcriptional induction of DNA repair genes in response to
DNA damage. Polyclonal antibodies raised against the Rad9 protein recognized
several polypeptides in asynchronous cultures, and in cells arrested in S or G2/M
phases while a single form was observed in G1-arrested cells. Treatment with
various DNA damaging agents, i.e. UV, ionizing radiation or methyl methane
sulfonate, resulted in the appearance of hypermodified forms of the protein. All
modifications detected during a normal cell cycle and after DNA damage were
sensitive to phosphatase treatment, indicating that they resulted from
phosphorylation. Damage-induced hyperphosphorylation of Rad9 correlated with
checkpoint functions (cell-cycle arrest and transcriptional induction) and was
cell-cycle stage- and progression-independent. In asynchronous cultures, Rad9
hyperphosphorylation was dependent on MEC1 and TEL1, homologues of the ATR and
ATM genes. In G1-arrested cells, damage-dependent hyperphosphorylation required
functional MEC1 in addition to RAD17, RAD24, MEC3 and DDC1, demonstrating cell
cycle stage specificity of the checkpoint genes in this response to DNA damage.
Analysis of checkpoint protein interactions after DNA damage revealed that Rad9
physically associates with Rad53.
PMID- 9755169
TI - Cdc18 transcription and proteolysis couple S phase to passage through mitosis.
AB - In fission yeast, cdc18p plays a critical role in bringing about the onset of S
phase. We show that cdc18p expression is subject to a complex sequence of cell
cycle controls which ensure that cdc18p levels rise dramatically as cells exit
mitosis, before the appearance of CDK activity in G1. We find that transcription
of cdc18, together with the transcription of other cdc10p/res1p targets, is first
initiated as cells enter mitosis and continues even in cells arrested in mitosis
with highly condensed chromatin. However, cdc18p cannot accumulate during mitosis
because it is targeted for proteolysis by mitotic cdc2p-protein kinase-mediated
phosphorylation. On exit from mitosis, the cdc2p mitotic kinase activity falls,
stabilizing cdc18p, which then rapidly accumulates. This combination of mitotic
transcription and CDK-mediated proteolysis ensures that progression through
mitosis simultaneously prepares cells for DNA replication. During S phase, cdc18
transcription is then switched off, preventing the re-initiation of DNA synthesis
until the completion of the next round of mitosis.
PMID- 9755170
TI - Xenopus Cdc45-dependent loading of DNA polymerase alpha onto chromatin under the
control of S-phase Cdk.
AB - At the onset of S phase, chromosomal replication is initiated by the loading of
DNA polymerase alpha onto replication origins. However, the molecular mechanisms
for controlling the initiation are poorly understood. Using Xenopus egg extract,
we report here the identification of a Xenopus homolog of Cdc45, a yeast protein
essential for the initiation of replication, which is shown to be an essential
molecule for the initiation of replication via the loading of DNA polymerase
alpha onto chromatin. XCdc45, by physically interacting with the polymerase in
the extract, became associated with chromatin only after nuclear formation.
During S phase, XCdc45 co-localized with the polymerase in the nuclei, and the
loading of the polymerase, which depended on endogenous XCdc45, was facilitated
by exogenously added recombinant XCdc45. These findings, together with the
apparent requirement of S-phase-cdk activity for the loading of XCdc45, suggest
that XCdc45, under the control of S-phase cdk, plays a pivotal role in the
loading of DNA polymerase alpha onto chromatin.
PMID- 9755171
TI - Cloning of mammalian Ire1 reveals diversity in the ER stress responses.
AB - Cells modify their gene expression pattern in response to stress signals
emanating from the endoplasmic reticulum (ER). The well-characterized aspect of
this response consists of the activation of genes that encode protein chaperones
and other ER resident proteins, and is conserved between mammals and yeast. In
mammalian cells, however, ER stress also activates other pathways, including the
expression of the transcription factor CHOP/GADD153 and its downstream target
genes. ER stress is also linked to the development of programmed cell death, a
phenomenon in which CHOP plays an important role. Here we report on the cloning
of a murine homolog of yeast IRE1, an essential upstream component of the ER
stress-response in yeast. The mammalian Ire1 is located in the ER membrane and
its over-expression in mammalian cells activates both the endogenous ER chaperone
GRP78/BiP and CHOP-encoding genes. Over-expression of a dominant-negative form of
Ire1 blocks the induction of GRP78/BiP and CHOP in response to the ER stress
induced by tunicamycin treatment. Over-expression of murine Ire1 also leads to
the development of programmed cell death in transfected cells. These results
indicate that a single upstream component, Ire1, plays a role in multiple facets
of the ER stress-response in mammalian cells.
PMID- 9755172
TI - A new long form of Sox5 (L-Sox5), Sox6 and Sox9 are coexpressed in chondrogenesis
and cooperatively activate the type II collagen gene.
AB - Transcripts for a new form of Sox5, called L-Sox5, and Sox6 are coexpressed with
Sox9 in all chondrogenic sites of mouse embryos. A coiled-coil domain located in
the N-terminal part of L-Sox5, and absent in Sox5, showed >90% identity with a
similar domain in Sox6 and mediated homodimerization and heterodimerization with
Sox6. Dimerization of L-Sox5/Sox6 greatly increased efficiency of binding of the
two Sox proteins to DNA containing adjacent HMG sites. L-Sox5, Sox6 and Sox9
cooperatively activated expression of the chondrocyte differentiation marker
Col2a1 in 10T1/2 and MC615 cells. A 48 bp chondrocyte-specific enhancer in this
gene, which contains several HMG-like sites that are necessary for enhancer
activity, bound the three Sox proteins and was cooperatively activated by the
three Sox proteins in non-chondrogenic cells. Our data suggest that L-Sox5/Sox6
and Sox9, which belong to two different classes of Sox transcription factors,
cooperate with each other in expression of Col2a1 and possibly other genes of the
chondrocytic program.
PMID- 9755173
TI - Identification of Bach2 as a B-cell-specific partner for small maf proteins that
negatively regulate the immunoglobulin heavy chain gene 3' enhancer.
AB - Maf family transcription factors are important regulators in various
differentiation systems. Putative Maf recognition elements (MAREs) are found in
the 3' enhancer region of the immunoglobulin heavy chain (IgH) gene. These
elements are bound in B-cell extracts by a heterodimeric protein complex
containing both Bach2 and a small Maf protein. Analysis of normal hematopoietic
cells revealed that Bach2 is specifically expressed in B cells. Bach2 is
abundantly expressed in the early stages of B-cell differentiation and turned off
in terminally differentiated cells. Bach2 acts together with MafK as a negative
effector of the IgH 3' enhancer and binds to the co-repressor SMRT (silencing
mediator of retinoid and thyroid receptor). Hence the Bach2-small-Maf heterodimer
may represent the first example of a B-cell lineage, and of a developmental stage
restricted negative effector of the MARE in the IgH 3' enhancer region.
PMID- 9755175
TI - Srb/mediator proteins interact functionally and physically with transcriptional
repressor Sfl1.
AB - Srb/mediator proteins that are associated with RNA polymerase II holoenzyme have
been implicated in transcriptional repression in Saccharomyces cerevisiae. We
show here that the defect in repression of SUC2 caused by mutation of SRB8, SRB9,
SRB11, SIN4 or ROX3 is suppressed by increased dosage of the SFL1 gene, and the
genetic behavior of the sfl1Delta mutation provides further evidence for a
functional relationship. Sfl1 acts on SUC2 through a repression site located
immediately 5' to the TATA box, and Sfl1 binds this DNA sequence in vitro.
Moreover, LexA-Sfl1 represses transcription of a reporter, and repression is
reduced in an srb9 mutant. Finally, we show that Sfl1 co-immunoprecipitates from
cell extracts with Srb9, Srb11, Sin4 and Rox3. We propose that Sfl1, when bound
to its site, interacts with Srb/mediator proteins to inhibit transcription by RNA
polymerase II holoenzyme.
PMID- 9755174
TI - Expression of the LIM-homeobox gene LH2 generates immortalized steel factor
dependent multipotent hematopoietic precursors.
AB - The genes controlling self-renewal and differentiation in the hematopoietic
system are largely unknown. The LIM-homeobox genes are known to be important for
asymmetric cell divisions and differentiation of specific cell types and organs.
One member of this family, LH2, is expressed in fetal liver at the time of active
hematopoiesis. Therefore, we have assessed the function of LH2 during the
formation and initial expansion of the hematopoietic system by differentiating
LH2-transduced embryonic stem (ES) cells in vitro. This procedure generated
multipotent hematopoietic precursor cell (HPC) lines that required Steel factor
for growth. HPC lines have been maintained in an undifferentiated state in
culture for >7 months. Other growth factors tested efficiently induce terminal
differentiation of HPCs into various mature myeloid lineages. Steel factor is
also required and acts synergistically with the other growth factors to generate
multilineage colonies from the HPCs. These HPC lines express transcription
factors that are consistent with an immature progenitor, and the pattern of cell
surface marker expression is similar to that of early fetal multipotent
hematopoietic progenitors. Collectively, these data suggest that the HPC lines
represent an early fetal multipotent hematopoietic progenitor, and suggest a role
for LH2 in the control of cell fate decision and/or proliferation in the
hematopoietic system.
PMID- 9755176
TI - Kruppel acts as a developmental switch gene that mediates Notch signalling
dependent tip cell differentiation in the excretory organs of Drosophila.
AB - Cell proliferation in the excretory organs of Drosophila, the Malpighian tubules
(MT), is under the control of a neural tip cell. This unique cell is singled out
from equivalent MT primordial cells in response to Notch signalling. We show that
the gene Kruppel (Kr), best known for its segmentation function in the early
embryo, is under the control of the Notch-dependent signalling process. Lack-of
function and gain-of-function experiments demonstrate that Kr activity determines
the neural fate of tip cells by acting as a direct downstream target of proneural
basic helix-loop-helix (bHLH) proteins that are restricted in response to Notch
signalling. We have identified a unique cis-acting element that mediates all
spatial and temporal aspects of Kr gene expression during MT development. This
element contains functional binding sites for the restricted proneural bHLH
factors and Fork head protein which is expressed in all MT cells. Our results
suggest a mechanism in which these transcription factors cooperate to set up a
unique cell fate within an equivalence group of cells by restricting the activity
of the developmental switch gene Kr in response to Notch signalling.
PMID- 9755177
TI - sigmaR, an RNA polymerase sigma factor that modulates expression of the
thioredoxin system in response to oxidative stress in Streptomyces coelicolor
A3(2).
AB - We have identified an RNA polymerase sigma factor, sigmaR, that is part of a
system that senses and responds to thiol oxidation in the Gram-positive,
antibiotic-producing bacterium Streptomyces coelicolor A3(2). Deletion of the
gene (sigR) encoding sigmaR caused sensitivity to the thiol-specific oxidant
diamide and to the redox cycling compounds menadione and plumbagin. This
correlated with reduced levels of disulfide reductase activity and an inability
to induce this activity on exposure to diamide. The trxBA operon, encoding
thioredoxin reductase and thioredoxin, was found to be under the direct control
of sigmaR. trxBA is transcribed from two promoters, trxBp1 and trxBp2, separated
by 5-6 bp. trxBp1 is transiently induced at least 50-fold in response to diamide
treatment in a sigR-dependent manner. Purified sigmaR directed transcription from
trxBp1 in vitro, indicating that trxBp1 is a target for sigmaR. Transcription of
sigR itself initiates at two promoters, sigRp1 and sigRp2, which are separated by
173 bp. The sigRp2 transcript was undetectable in a sigR-null mutant, and
purified sigmaR could direct transcription from sigRp2 in vitro, indicating that
sigR is positively autoregulated. Transcription from sigRp2 was also transiently
induced (70-fold) following treatment with diamide. We propose a model in which
sigmaR induces expression of the thioredoxin system in response to cytoplasmic
disulfide bond formation. Upon reestablishment of normal thiol levels, sigmaR
activity is switched off, resulting in down-regulation of trxBA and sigR. We
present evidence that the sigmaR system also functions in the actinomycete
pathogen Mycobacterium tuberculosis.
PMID- 9755178
TI - Modifications of U2 snRNA are required for snRNP assembly and pre-mRNA splicing.
AB - Among the spliceosomal snRNAs, U2 has the most extensive modifications, including
a 5' trimethyl guanosine (TMG) cap, ten 2'-O-methylated residues and 13
pseudouridines. At short times after injection, cellularly derived (modified) U2
but not synthetic (unmodified) U2 rescues splicing in Xenopus oocytes depleted of
endogenous U2 by RNase H targeting. After prolonged reconstitution, synthetic U2
regenerates splicing activity; a correlation between the extent of U2
modification and U2 function in splicing is observed. Moreover, 5-fluorouridine
containing U2 RNA, a potent inhibitor of U2 pseudouridylation, specifically
abolishes rescue by synthetic U2, while rescue by cellularly derived U2 is not
affected. By creating chimeric U2 molecules in which some sequences are from
cellularly derived U2 and others are from in vitro transcribed U2, we demonstrate
that the functionally important modifications reside within the 27 nucleotides at
the 5' end of U2. We further show that 2'-O-methylation and pseudouridylation
activities reside in the nucleus and that the 5' TMG cap is not necessary for
internal modification but is crucial for splicing activity. Native gel analysis
reveals that unmodified U2 is not incorporated into the spliceosome. Examination
of the U2 protein profile and glycerol-gradient analysis argue that U2
modifications directly contribute to conversion of the 12S to the 17S U2 snRNP
particle, which is essential for spliceosome assembly.
PMID- 9755179
TI - Accumulation of mitochondrially synthesized Saccharomyces cerevisiae Cox2p and
Cox3p depends on targeting information in untranslated portions of their mRNAs.
AB - The essential products of the yeast mitochondrial translation system are seven
hydrophobic membrane proteins and Var1p, a hydrophilic protein in the small
ribosomal subunit. Translation of the membrane proteins depends on nuclearly
encoded, mRNA-specific translational activators that recognize the 5'
untranslated leaders of their target mRNAs. These translational activators are
themselves membrane associated and could therefore tether translation to the
inner membrane. In this study, we tested whether chimeric mRNAs with the
untranslated sequences normally present on the mRNA encoding soluble Var1p, can
direct functional expression of coding sequences specifying the integral membrane
proteins Cox2p and Cox3p. DNA sequences specifying these chimeric mRNAs were
inserted into mtDNA at the VAR1 locus and expressed in strains containing a
nuclearly localized plasmid that supplies a functional form of Var1p, imported
from the cytoplasm. Although cells expressing these chimeric mRNAs actively
synthesized both membrane proteins, they were severely deficient in cytochrome c
oxidase activity and in the accumulation of Cox2p and Cox3p, respectively. These
data strongly support the physiological importance of interactions between
membrane-bound mRNA-specific translational activators and the native 5'
untranslated leaders of the COX2 and COX3 mRNAs for localizing productive
synthesis of Cox2p and Cox3p to the inner membrane.
PMID- 9755180
TI - Mechanism of inhibition of Psi+ prion determinant propagation by a mutation of
the N-terminus of the yeast Sup35 protein.
AB - The SUP35 gene of Saccharomyces cerevisiae encodes the polypeptide chain release
factor eRF3. This protein (also called Sup35p) is thought to be able to undergo a
heritable conformational switch, similarly to mammalian prions, giving rise to
the cytoplasmically inherited Psi+ determinant. A dominant mutation (PNM2 allele)
in the SUP35 gene causing a Gly58-->Asp change in the Sup35p N-terminal domain
eliminates Psi+. Here we observed that the mutant Sup35p can be converted to the
prion-like form in vitro, but such conversion proceeds slower than that of wild
type Sup35p. The overexpression of mutant Sup35p induced the de novo appearance
of Psi+ cells containing the prion-like form of mutant Sup35p, which was able to
transmit its properties to wild-type Sup35p both in vitro and in vivo. Our data
indicate that this Psi+-eliminating mutation does not alter the initial binding
of Sup35p molecules to the Sup35p Psi+-specific aggregates, but rather inhibits
its subsequent prion-like rearrangement and/or binding of the next Sup35p
molecule to the growing prion-like Sup35p aggregate.
PMID- 9755181
TI - Rotavirus RNA-binding protein NSP3 interacts with eIF4GI and evicts the poly(A)
binding protein from eIF4F.
AB - Most eukaryotic mRNAs contain a 5'cap structure and a 3'poly(A) sequence that
synergistically increase the efficiency of translation. Rotavirus mRNAs are
capped, but lack poly(A) sequences. During rotavirus infection, the viral protein
NSP3A is bound to the viral mRNAs 3' end. We looked for cellular proteins that
could interact with NSP3A, using the two-hybrid system in yeast. Screening a CV1
cell cDNA library allowed us to isolate a partial cDNA of the human eukaryotic
initiation factor 4GI (eIF4GI). The interaction of NSP3A with eIF4GI was
confirmed in rotavirus infected cells by co-immunoprecipitation and in vitro with
NSP3A produced in Escherichia coli. In addition, we show that the amount of
poly(A) binding protein (PABP) present in eIF4F complexes decreases during
rotavirus infection, even though eIF4A and eIF4E remain unaffected. PABP is
removed from the eIF4F complex after incubation in vitro with the C-terminal part
of NSP3A, but not with its N-terminal part produced in E.coli. These results show
that a physical link between the 5' and the 3' ends of mRNA is necessary for the
efficient translation of viral mRNAs and strongly support the closed loop model
for the initiation of translation. These results also suggest that NSP3A, by
taking the place of PABP on eIF4GI, is responsible for the shut-off of cellular
protein synthesis.
PMID- 9755182
TI - Host proteins can stimulate Tn7 transposition: a novel role for the ribosomal
protein L29 and the acyl carrier protein.
AB - The bacterial transposon Tn7 is distinguished by its ability to insert at a high
frequency into a specific site in the Escherichia coli chromosome called attTn7.
Tn7 insertion into attTn7 requires four Tn7-encoded transposition proteins: TnsA,
TnsB, TnsC and TnsD. The selection of attTn7 is determined by TnsD, a sequence
specific DNA-binding protein. TnsD binds attTn7 and interacts with TnsABC, the
core transposition machinery, which facilitates the insertion of Tn7 into attTn7.
In this work, we report the identification of two host proteins, the ribosomal
protein L29 and the acyl carrier protein (ACP), which together stimulate the
binding of TnsD to attTn7. The combination of L29 and ACP also stimulates Tn7
transposition in vitro. Interestingly, mutations in L29 drastically decrease Tn7
transposition in vivo, and this effect of L29 on Tn7 transposition is specific
for TnsABC+D reactions.
PMID- 9755184
TI - RNA-dependent activation of primer RNA production by influenza virus polymerase:
different regions of the same protein subunit constitute the two required RNA
binding sites.
AB - The capped RNA primers required for the initiation of influenza virus mRNA
synthesis are produced by the viral polymerase itself, which consists of three
proteins PB1, PB2 and PA. Production of primers is activated only when the 5'-
and 3'-terminal sequences of virion RNA (vRNA) bind sequentially to the
polymerase, indicating that vRNA molecules function not only as templates for
mRNA synthesis but also as essential cofactors which activate catalytic
functions. Using thio U-substituted RNA and UV crosslinking, we demonstrate that
the 5' and 3' sequences of vRNA bind to different amino acid sequences in the
same protein subunit, the PB1 protein. Mutagenesis experiments proved that these
two amino acid sequences constitute the functional RNA-binding sites. The 5'
sequence of vRNA binds to an amino acid sequence centered around two arginine
residues at positions 571 and 572, causing an allosteric alteration which
activates two new functions of the polymerase complex. In addition to the PB2
protein subunit acquiring the ability to bind 5'-capped ends of RNAs, the PB1
protein itself acquires the ability to bind the 3' sequence of vRNA, via a
ribonucleoprotein 1 (RNP1)-like motif, amino acids 249-256, which contains two
phenylalanine residues required for binding. Binding to this site induces a
second allosteric alteration which results in the activation of the endonuclease
that produces the capped RNA primers needed for mRNA synthesis. Hence, the PB1
protein plays a central role in the catalytic activity of the viral polymerase,
not only in the catalysis of RNA-chain elongation but also in the activation of
the enzyme activities that produce capped RNA primers.
PMID- 9755183
TI - Sequence specificity of viral end DNA binding by HIV-1 integrase reveals critical
regions for protein-DNA interaction.
AB - HIV-1 integrase specifically recognizes and cleaves viral end DNA during the
initial step of retroviral integration. The protein and DNA determinants of the
specificity of viral end DNA binding have not been clearly identified. We have
used mutational analysis of the viral end LTR sequence, in vitro selection of
optimal viral end sequences, and specific photocrosslinking to identify regions
of integrase that interact with specific bases in the LTR termini. The results
highlight the involvement of the disordered loop of the integrase core domain,
specifically residues Q148 and Y143, in binding to the terminal portion of the
viral DNA ends. Additionally, we have identified positions upstream in the LTR
termini which interact with the C-terminal domain of integrase, providing
evidence for the role of that domain in stabilization of viral DNA binding.
Finally, we have located a region centered 12 bases from the viral DNA terminus
which appears essential for viral end DNA binding in the presence of magnesium,
but not in the presence of manganese, suggesting a differential effect of
divalent cations on sequence-specific binding. These results help to define
important regions of contact between integrase and viral DNA, and assist in the
formulation of a molecular model of this vital interaction.
PMID- 9755185
TI - An extract from "Memoirs for family and friends".
PMID- 9755186
TI - Sex and the evolution of intrahost competition in RNA virus phi6.
AB - Sex allows beneficial mutations that occur in separate lineages to be fixed in
the same genome. For this reason, the Fisher-Muller model predicts that
adaptation to the environment is more rapid in a large sexual population than in
an equally large asexual population. Sexual reproduction occurs in populations of
the RNA virus phi6 when multiple bacteriophages coinfect the same host cell.
Here, we tested the model's predictions by determining whether sex favors more
rapid adaptation of phi6 to a bacterial host, Pseudomonas phaseolicola. Replicate
populations of phi6 were allowed to evolve in either the presence or absence of
sex for 250 generations. All experimental populations showed a significant
increase in fitness relative to the ancestor, but sex did not increase the rate
of adaptation. Rather, we found that the sexual and asexual treatments also
differ because intense intrahost competition between viruses occurs during
coinfection. Results showed that the derived sexual viruses were selectively
favored only when coinfection is common, indicating that within-host competition
detracts from the ability of viruses to exploit the host. Thus, sex was not
advantageous because the cost created by intrahost competition was too strong.
Our findings indicate that high levels of coinfection exceed an optimum where sex
may be beneficial to populations of phi6, and suggest that genetic conflicts can
evolve in RNA viruses.
PMID- 9755187
TI - Mechanism and control of interspecies recombination in Escherichia coli. I.
Mismatch repair, methylation, recombination and replication functions.
AB - A genetic analysis of interspecies recombination in Escherichia coli between the
linear Hfr DNA from Salmonella typhimurium and the circular recipient chromosome
reveals some fundamental aspects of recombination between related DNA sequences.
The MutS and MutL mismatch binding proteins edit (prevent) homeologous
recombination between these 16% diverged genomes by at least two distinct
mechanisms. One is MutH independent and presumably acts by aborting the initiated
recombination through the UvrD helicase activity. The RecBCD nuclease might
contribute to this editing step, presumably by preventing reiterated initiations
of recombination at a given locus. The other editing mechanism is MutH dependent,
requires unmethylated GATC sequences, and probably corresponds to an incomplete
long-patch mismatch repair process that does not depend on UvrD helicase
activity. Insignificant effects of the Dam methylation of parental DNAs suggest
that unmethylated GATC sequences involved in the MutH-dependent editing are newly
synthesized in the course of recombination. This hypothetical, recombination
associated DNA synthesis involves PriA and RecF functions, which, therefore,
determine the extent of MutH effect on interspecies recombination. Sequence
divergence of recombining DNAs appears to limit the frequency, length, and
stability of early heteroduplex intermediates, which can be stabilized, and the
recombinants mature via the initiation of DNA replication.
PMID- 9755188
TI - Reassigning cysteine in the genetic code of Escherichia coli.
AB - We investigated directed deviations from the universal genetic code. Mutant tRNAs
that incorporate cysteine at positions corresponding to the isoleucine AUU, AUC,
and AUA and methionine AUG codons were introduced in Escherichia coli K12.
Missense mutations at the cysteine catalytic site of thymidylate synthase were
systematically crossed with synthetic suppressor tRNACys genes coexpressed from
compatible plasmids. Strains harboring complementary codon/anticodon associations
could be stably propagated as thymidine prototrophs. A plasmid-encoded tRNACys
reading the codon AUA persisted for more than 500 generations in a strain
requiring its suppressor activity for thymidylate biosynthesis, but was
eliminated from a strain not requiring it. Cysteine miscoding at the codon AUA
was also enforced in the active site of amidase, an enzyme found in Helicobacter
pylori and not present in wild-type E. coli. Propagating the amidase missense
mutation in E. coli with an aliphatic amide as nitrogen source required the
overproduction of Cys-tRNA synthetase together with the complementary suppressor
tRNACys. The toxicity of cysteine miscoding was low in all our strains. The small
size and amphiphilic character of this amino acid may render it acceptable as a
replacement at most protein positions and thus apt to overcome the steric and
polar constraints that limit evolution of the genetic code.
PMID- 9755189
TI - The Schizosaccharomyces pombe cho1+ gene encodes a phospholipid
methyltransferase.
AB - The isolation of mutants of Schizosaccharomyces pombe defective in the synthesis
of phosphatidylcholine via the methylation of phosphatidylethanolamine is
reported. These mutants are choline auxotrophs and fall into two unlinked
complementation groups, cho1 and cho2. We also report the analysis of the cho1+
gene, the first structural gene encoding a phospholipid biosynthetic enzyme from
S. pombe to be cloned and characterized. The cho1+ gene disruption mutant
(cho1Delta) is viable if choline is supplied and resembles the cho1 mutants
isolated after mutagenesis. Sequence analysis of the cho1+ gene indicates that it
encodes a protein closely related to phospholipid methyltransferases from
Saccharomyces cerevisiae and rat. Phospholipid methyltransferases encoded by a
rat liver cDNA and the S. cerevisiae OPI3 gene are both able to complement the
choline auxotrophy of the S. pombe cho1 mutants. These results suggest that both
the structure and function of the phospholipid N-methyltransferases are broadly
conserved among eukaryotic organisms.
PMID- 9755190
TI - Histone deacetylase homologs regulate epigenetic inheritance of transcriptional
silencing and chromosome segregation in fission yeast.
AB - Position-effect control at the silent mat2-mat3 interval and at centromeres and
telomeres in fission yeast is suggested to be mediated through the assembly of
heterochromatin-like structures. Therefore, trans-acting genes that affect
silencing may encode either chromatin proteins, factors that modify them, or
factors that affect chromatin assembly. Here, we report the identification of an
essential gene, clr6 (cryptic loci regulator), which encodes a putative histone
deacetylase that when mutated affects epigenetically maintained repression at the
mat2-mat3 region and at centromeres and reduces the fidelity of chromosome
segregation. Furthermore, we show that the Clr3 protein, when mutated, alleviates
recombination block at mat region as well as silencing at donor loci and at
centromeres and telomeres, also shares strong homology to known histone
deacetylases. Genetic analyses indicate that silencing might be regulated by at
least two overlapping histone deacetylase activities. We also found that
transient inhibition of histone deacetylase activity by trichostatin A results in
the increased missegregation of chromosomes in subsequent generations and,
remarkably, alters the imprint at the mat locus, causing the heritable conversion
of the repressed epigenetic state to the expressed state. This work supports the
model that the level of histone deacetylation has a role in the assembly of
repressive heterochromatin and provides insight into the mechanism of epigenetic
inheritance.
PMID- 9755191
TI - An arf1Delta synthetic lethal screen identifies a new clathrin heavy chain
conditional allele that perturbs vacuolar protein transport in Saccharomyces
cerevisiae.
AB - ADP-ribosylation factor (ARF) is a small GTP-binding protein that is thought to
regulate the assembly of coat proteins on transport vesicles. To identify factors
that functionally interact with ARF, we have performed a genetic screen in
Saccharomyces cerevisiae for mutations that exhibit synthetic lethality with an
arf1Delta allele and defined seven genes by complementation tests (SWA1-7 for
synthetically lethal with arf1Delta). Most of the swa mutants exhibit phenotypes
comparable to arf1Delta mutants such as temperature-conditional growth,
hypersensitivity to fluoride ions, and partial protein transport and
glycosylation defects. Here, we report that swa5-1 is a new temperature-sensitive
allele of the clathrin heavy chain gene (chc1-5), which carries a frameshift
mutation near the 3' end of the CHC1 open reading frame. This genetic interaction
between arf1 and chc1 provides in vivo evidence for a role for ARF in clathrin
coat assembly. Surprisingly, strains harboring chc1-5 exhibited a significant
defect in transport of carboxypeptidase Y or carboxypeptidase S to the vacuole
that was not observed in other chc1 ts mutants. The kinetics of invertase
secretion or transport of alkaline phosphatase to the vacuole were not
significantly affected in the chc1-5 mutant, further implicating clathrin
specifically in the Golgi to vacuole transport pathway for carboxypeptidase Y.
PMID- 9755192
TI - Alteration of N-terminal phosphoesterase signature motifs inactivates
Saccharomyces cerevisiae Mre11.
AB - Saccharomyces cerevisiae Mre11, Rad50, and Xrs2 function in a protein complex
that is important for nonhomologous recombination. Null mutants of MRE11, RAD50,
and XRS2 are characterized by ionizing radiation sensitivity and mitotic
interhomologue hyperrecombination. We mutagenized the four highly conserved
phosphoesterase signature motifs of Mre11 to create mre11-11, mre11-2, mre11-3,
and mre11-4 and assessed the functional consequences of these mutant alleles with
respect to mitotic interhomologue recombination, chromosome loss, ionizing
radiation sensitivity, double-strand break repair, and protein interaction. We
found that mre11 mutants that behaved as the null were sensitive to ionizing
radiation and deficient in double-strand break repair. We also observed that
these null mutants exhibited a hyperrecombination phenotype in mitotic cells,
consistent with previous reports, but did not exhibit an increased frequency of
chromosome loss. Differential ionizing radiation sensitivities among the
hypomorphic mre11 alleles correlated with the trends observed in the other
phenotypes examined. Two-hybrid interaction testing showed that all but one of
the mre11 mutations disrupted the Mre11-Rad50 interaction. Mutagenesis of the
phosphoesterase signatures in Mre11 thus demonstrated the importance of these
conserved motifs for recombinational DNA repair.
PMID- 9755193
TI - Mutations in the membrane anchor of yeast cytochrome c1 compensate for the
absence of Oxa1p and generate carbonate-extractable forms of cytochrome c1.
AB - Oxa1p is a mitochondrial inner membrane protein that is mainly required for the
insertion/assembly of complex IV and ATP synthase and is functionally conserved
in yeasts, humans, and plants. We have isolated several independent suppressors
that compensate for the absence of Oxa1p. Molecular cloning and sequencing reveal
that the suppressor mutations (CYT1-1 to -6) correspond to amino acid
substitutions that are all located in the membrane anchor of cytochrome c1 and
decrease the hydrophobicity of this anchor. Cytochrome c1 is a catalytic subunit
of complex III, but the CYT1-1 mutation does not seem to affect the electron
transfer activity. The double-mutant cyt1-1,164, which has a drastically reduced
electron transfer activity, still retains the suppressor activity. Altogether,
these results suggest that the suppressor function of cytochrome c1 is
independent of its electron transfer activity. In addition to the membrane-bound
cytochrome c1, carbonate-extractable forms accumulate in all the suppressor
strains. We propose that these carbonate-extractable forms of cytochrome c1 are
responsible for the suppressor function by preventing the degradation of the
respiratory complex subunits that occur in the absence of Oxa1p.
PMID- 9755195
TI - Regulation of gene expression during the vegetative incompatibility reaction in
Podospora anserina. Characterization of three induced genes.
AB - Vegetative incompatibility in fungi limits the formation of viable heterokaryons.
It results from the coexpression of incompatible genes in the heterokaryotic
cells and leads to a cell death reaction. In Podospora anserina, a modification
of gene expression takes place during this reaction, including a strong decrease
of total RNA synthesis and the appearance of a new set of proteins. Using in
vitro translation of mRNA and separation of protein products by two-dimensional
gel electrophoresis, we have shown that the mRNA content of cells is
qualitatively modified during the progress of the incompatibility reaction. Thus,
gene expression during vegetative incompatibility is regulated, at least in part,
by variation of the mRNA content of specific genes. A subtractive cDNA library
enriched in sequences preferentially expressed during incompatibility was
constructed. This library was used to identify genomic loci corresponding to
genes whose mRNA is induced during incompatibility. Three such genes were
characterized and named idi genes for genes induced during incompatibility. Their
expression profiles suggest that they may be involved in different steps of the
incompatibility reaction. The putative IDI proteins encoded by these genes are
small proteins with signal peptides. IDI-2 protein is a cysteine-rich protein.
IDI-2 and IDI-3 proteins display some similarity in a tryptophan-rich region.
PMID- 9755194
TI - Identification of high-copy disruptors of telomeric silencing in Saccharomyces
cerevisiae.
AB - The ends of chromosomes in Saccharomyces cerevisiae initiate a repressive
chromatin structure that spreads internally and inhibits the transcription of
nearby genes, a phenomenon termed telomeric silencing. To investigate the
molecular basis of this process, we carried out a genetic screen to identify
genes whose overexpression disrupts telomeric silencing. We thus isolated 10 DOT
genes (disruptor of telomeric silencing). Among these were genes encoding
chromatin component Sir4p, DNA helicase Dna2p, ribosomal protein L32, and two
proteins of unknown function, Asf1p and Ifh1p. The collection also included genes
that had not previously been identified: DOT1, DOT4, DOT5, DOT6, and TLC1, which
encodes the RNA template component of telomerase. With the exception of TLC1, all
these genes, particularly DOT1 and DOT4, also reduced silencing at other
repressed loci (HM loci and rDNA) when overexpressed. Moreover, deletion of the
latter two genes weakened silencing as well, suggesting that DOT1 and DOT4
normally play important roles in gene repression. DOT1 deletion also affected
telomere tract length. The function of Dot1p is not known. The sequence of Dot4p
suggests that it is a ubiquitin-processing protease. Taken together, the DOT
genes include both components and regulators of silent chromatin.
PMID- 9755196
TI - Tetrahymena mutants with short telomeres.
AB - Telomere length is dynamic in many organisms. Genetic screens that identify
mutants with altered telomere lengths are essential if we are to understand how
telomere length is regulated in vivo. In Tetrahymena thermophila, telomeres
become long at 30 degrees, and growth rate slows. A slow-growing culture with
long telomeres is often overgrown by a variant cell type with short telomeres and
a rapid-doubling rate. Here we show that this variant cell type with short
telomeres is in fact a mutant with a genetic defect in telomere length
regulation. One of these telomere growth inhibited forever (tgi) mutants was
heterozygous for a telomerase RNA mutation, and this mutant telomerase RNA caused
telomere shortening when overexpressed in wild-type cells. Several other tgi
mutants were also likely to be heterozygous at their mutant loci, since they
reverted to wild type when selective pressure for short telomeres was removed.
These results illustrate that telomere length can regulate growth rate in
Tetrahymena and that this phenomenon can be exploited to identify genes involved
in telomere length regulation.
PMID- 9755197
TI - The male-determining activity on the Y chromosome of the housefly (Musca
domestica L.) consists of separable elements.
AB - In the common housefly, the presence or absence of a male-determining factor, M,
is responsible for sex determination. In different strains, M has been found on
the Y, on the X, or on any of the five autosomes. By analyzing a Y-autosomal
translocation and a ring-shaped, truncated Y chromosome, we could show that M on
the Y consists of at least two regions with M activity: One of them can be
assigned to the short arm of the Y chromosome (MYS), which is largely C-banding
negative, the other region lies on the C-banding positive long arm of the Y,
including the centromeric part (MYL). Each region alone behaves as a hypomorphic
M factor, causing many carriers to develop as intersexes of the mosaic type
instead of as males. When introduced into the female germ line by transplantation
of progenitor germ cells (pole cells), the MYS shows an almost complete maternal
effect that predetermines 96% of the genotypic female (NoM) animals to develop as
males. In contrast, the MYL has largely lost its maternal effect, and most of the
NoM animals develop as females. Increasing the amount of product made by either
of the two hypomorphic M factors (by combining the MYS and MYL or two MYS) leads
to complete male development in almost every case. We thus assume that the Y
chromosome carries at least two copies of M, and that these are functionally
equivalent.
PMID- 9755198
TI - Functional analysis of the fibrinogen-related scabrous gene from Drosophila
melanogaster identifies potential effector and stimulatory protein domains.
AB - The scabrous (sca) gene encodes a secreted dimeric glycoprotein with putative
coiled-coil domains N-terminally and a C-terminal region related to the blood
clot protein fibrinogen. Homozygous sca mutants have extra bristle organs and
rough eyes. We describe a GAL4-based expression system for testing rescue of the
sca mutant phenotype by altered SCA proteins and for misexpression. We find that
deletion of the fibrinogen-related domain (FReD) greatly decreases SCA function,
confirming the importance of this conserved region. SCA function could not be
restored by FReDs from human fibrinogen chain genes. However, proteins lacking
any FReD still showed some function in both rescue and misexpression experiments,
suggesting that putative effector-binding regions lie outside this domain.
Consistent with this, proteins expressing only the FReD had no rescuing activity
but were recessive negative; i.e., they enhanced the phenotype of sca mutations
but had no phenotype in the presence of a wild-type sca allele. This suggests
that the FReD contributes to SCA function by binding to other components of the
bristle determination pathway, increasing the activity of the linked N-terminal
region.
PMID- 9755199
TI - Expression and properties of wild-type and mutant forms of the Drosophila sex
comb on midleg (SCM) repressor protein.
AB - The Sex comb on midleg (Scm) gene encodes a transcriptional repressor of the
Polycomb group (PcG). Here we show that SCM protein is nuclear and that its
expression is widespread during fly development. SCM protein contains a C
terminal domain, termed the SPM domain, which mediates protein-protein
interactions. The biochemical function of another domain consisting of two 100
amino-acid-long repeats, termed "mbt" repeats, is unknown. We have determined the
molecular lesions of nine Scm mutant alleles, which identify functional
requirements for specific domains. The Scm alleles were tested for genetic
interactions with mutations in other PcG genes. Intriguingly, three hypomorphic
Scm mutations, which map within an mbt repeat, interact with PcG mutations more
strongly than do Scm null alleles. The strongest interactions produce partial
synthetic lethality that affects doubly heterozygous females more severely than
males. We show that mbt repeat alleles produce stable SCM proteins that associate
with normal sites in polytene chromosomes. We also analyzed progeny from Scm
mutant germline clones to compare the effects of an mbt repeat mutation during
embryonic vs. pupal development. We suggest that the mbt repeat alleles produce
altered SCM proteins that incorporate into and impair function of PcG protein
complexes.
PMID- 9755200
TI - P-Element insertion at the polyhomeotic gene leads to formation of a novel
chimeric protein that negatively regulates yellow gene expression in P-element
induced alleles of Drosophila melanogaster.
AB - Polyhomeotic is a member of the Polycomb group (Pc-G) of homeotic repressors. The
proteins encoded by the Pc-G genes form repressive complexes on the polycomb
group response element sites. The phP1 mutation was induced by insertion of a 1.2
kb P element into the 5' transcribed nontranslated region of the proximal
polyhomeotic gene. The phP1 allele confers no mutant phenotype, but represses
transcription of P-element-induced alleles at the yellow locus. The phP1 allele
encodes a chimeric P-PH protein, consisting of the DNA-binding domain of the P
element and the PH protein lacking 12 amino-terminal amino acids. The P-PH,
Polycomb (PC), and Posterior sex combs (PSC) proteins were immunohistochemically
detected on polytene chromosomes in the regions of P-element insertions.
PMID- 9755201
TI - Modulation of MSL1 abundance in female Drosophila contributes to the sex
specificity of dosage compensation.
AB - Dosage compensation in Drosophila is the mechanism by which X-linked gene
expression is made equal in males and females. Proper regulation of this process
is critical to the survival of both sexes. Males must turn the male-specific
lethal (msl)-mediated pathway of dosage compensation on and females must keep it
off. The msl2 gene is the primary target of negative regulation in females.
Preventing production of MSL2 protein is sufficient to prevent dosage
compensation; however, ectopic expression of MSL2 protein in females is not
sufficient to induce an insurmountable level of dosage compensation, suggesting
that an additional component is limiting in females. A candidate for this
limiting factor is MSL1, because the amount of MSL1 protein in females is reduced
compared to males. We have identified two levels of negative regulation of msl1
in females. The predominant regulation is at the level of protein stability,
while a second regulatory mechanism functions at the level of protein synthesis.
Overcoming these control mechanisms by overexpressing both MSL1 and MSL2 in
females results in 100% female-specific lethality.
PMID- 9755202
TI - LUSH odorant-binding protein mediates chemosensory responses to alcohols in
Drosophila melanogaster.
AB - The molecular mechanisms mediating chemosensory discrimination in insects are
unknown. Using the enhancer trapping approach, we identified a new Drosophila
mutant, lush, with odorant-specific defects in olfactory behavior. lush mutant
flies are abnormally attracted to high concentrations of ethanol, propanol, and
butanol but have normal chemosensory responses to other odorants. We show that
wild-type flies have an active olfactory avoidance mechanism to prevent
attraction to concentrated alcohol, and this response is defective in lush
mutants. This suggests that the defective olfactory behavior associated with the
lush mutation may result from a specific defect in chemoavoidance. lush mutants
have a 3-kb deletion that produces a null allele of a new member of the
invertebrate odorant-binding protein family, LUSH. LUSH is normally expressed
exclusively in a subset of trichoid chemosensory sensilla located on the ventral
lateral surface of the third antennal segment. LUSH is secreted from nonneuronal
support cells into the sensillum lymph that bathes the olfactory neurons within
these sensilla. Reintroduction of a cloned wild-type copy of lush into the mutant
background completely restores wild-type olfactory behavior, demonstrating that
this odorant-binding protein is required in a subset of sensilla for normal
chemosensory behavior to a subset of odorants. These findings provide direct
evidence that odorant-binding proteins are required for normal chemosensory
behavior in Drosophila and may partially determine the chemical specificity of
olfactory neurons in vivo.
PMID- 9755203
TI - Evidence for 3' untranslated region-dependent autoregulation of the Drosophila
gene encoding the neuronal nuclear RNA-binding protein ELAV.
AB - The Drosophila locus embryonic lethal abnormal visual system (elav) encodes a
nuclear RNA-binding protein essential for normal neuronal differentiation and
maintenance of neurons. ELAV is thought to play its role by binding to RNAs
produced by other genes necessary for neuronal differentiation and consequently
to affect their metabolism by an as yet unknown mechanism. ELAV structural
homologues have been identified in a wide range of organisms, including humans,
indicating an important conserved role for the protein. Analysis of elav germline
transformants presented here shows that one copy of elav minigenes lacking a
complete 3' untranslated region (3' UTR) rescues null mutations at elav, but that
two copies are lethal. Additional in vivo experiments demonstrate that elav
expression is regulated through the 3' UTR of the gene and indicate that this
level of regulation is dependent upon ELAV itself. Because ELAV is an RNA-binding
protein, the simplest model to account for these findings is that ELAV binds to
the 3' UTR of its own RNA to autoregulate its expression. I discuss the
implications of these results for normal elav function.
PMID- 9755204
TI - Y-Linked male sterile mutations induced by P element in Drosophila melanogaster.
AB - The Y chromosome in Drosophila melanogaster is composed of highly repetitive
sequences and is essential only in the male germ line. We employed P-element
insertional mutagenesis to induce male sterile mutations in the Y chromosome. By
using a combination of two modifiers of position effect variegation, adding an
extra Y chromosome and increasing temperature, we isolated 61 P(ry+) elements in
the Y chromosome. Six of these Y-linked insertions (approximately 10%) induced
male sterile mutations that are mapped to two genes on the long and one on the
short arms of the Y chromosome. These mutations are revertible to the wild type
in a cell-autonomous and germ-line-dependent manner, consistent with previously
defined Y-linked gene functions. Phenotypes associated with these P-induced
mutations are similar to those resulting from deletions of the Y chromosome
regions corresponding to the male fertility genes. Three alleles of the kl-3 gene
on the Y long arm result in loss of the axonemal outer dynein arms in the
spermatid tail, while three ks-2 alleles on the Y short arm induce defects at
early postmeiotic stages. The recovery of the ms(Y) mutations induced by single P
element insertions will facilitate our effort to understand the structural and
functional properties of the Y chromosome.
PMID- 9755205
TI - Hidden effects of X chromosome introgressions on spermatogenesis in Drosophila
simulans x D. mauritiana hybrids unveiled by interactions among minor genetic
factors.
AB - One of the most frequent outcomes of interspecific hybridizations in Drosophila
is hybrid male sterility. Genetic dissection of this reproductive barrier has
revealed that the number of responsible factors is very high and that these
factors are frequently engaged in complex epistatic interactions. Traditionally,
research strategies have been based on contrasting introgressions of chromosome
segments that produce male sterility with those that allow fertility. Few studies
have investigated the phenotypes associated with the boundary between fertility
and sterility. In this study, we cointrogressed three different X chromosome
segments from Drosophila mauritiana into D. simulans. Hybrid males with these
three segments are usually fertile, by conventional fertility assays. However,
their spermatogenesis shows a significant slowdown, most manifest at lower
temperatures. Each of the three introgressed segments retards the arrival of
sperm to the seminal vesicles. Other small disturbances in spermatogenesis are
evident, which altogether lead to an overall reduction in the amount of motile
sperm in their seminal vesicles. These results suggest that a delay in the timing
of spermatogenesis, which might be brought about by the cumulative action of many
different factors of minor segment, may be the primary cause of hybrid male
sterility.
PMID- 9755206
TI - Quantitative genetic analysis of copia retrotransposon activity in inbred
Drosophila melanogaster lines.
AB - The rates of transcription and transposition of retrotransposons vary between
lines of Drosophila melanogaster. We have studied the genetics of differences in
copia retrotransposon activity by quantitative trait loci (QTL) mapping. Ninety
eight recombinant inbred lines were constructed from two parental lines
exhibiting a 10-fold difference in copia transcript level and a 100-fold
difference in transposition rate. The lines were scored for 126 molecular
markers, copia transcript level, and rate of copia transposition. Transcript
level correlated with copia copy number, and the difference in copia copy number
between parental lines accounted for 45.1% of copia transcript-level difference.
Most of the remaining difference was accounted for by two transcript-level QTL
mapping to cytological positions 27B-30D and 50F-57C on the second chromosome,
which accounted for 11.5 and 30.4%, respectively. copia transposition rate was
controlled by interacting QTL mapping to the region 27B-48D on the second and 61A
65A and 97D-100A on the third chromosome. The genes controlling copia transcript
level are thus not necessarily those involved in controlling copia transposition
rate. Segregation of modifying genes, rather than mutations, might explain the
variability in copia retrotransposon activity between lines.
PMID- 9755207
TI - The correlation between synonymous and nonsynonymous substitutions in Drosophila:
mutation, selection or relaxed constraints?
AB - Codon usage bias, the preferential use of particular codons within each codon
family, is characteristic of synonymous base composition in many species,
including Drosophila, yeast, and many bacteria. Preferential usage of particular
codons in these species is maintained by natural selection acting largely at the
level of translation. In Drosophila, as in bacteria, the rate of synonymous
substitution per site is negatively correlated with the degree of codon usage
bias, indicating stronger selection on codon usage in genes with high codon bias
than in genes with low codon bias. Surprisingly, in these organisms, as well as
in mammals, the rate of synonymous substitution is also positively correlated
with the rate of nonsynonymous substitution. To investigate this correlation, we
carried out a phylogenetic analysis of substitutions in 22 genes between two
species of Drosophila, Drosophila pseudoobscura and D. subobscura, in codons that
differ by one replacement and one synonymous change. We provide evidence for a
relative excess of double substitutions in the same species lineage that cannot
be explained by the simultaneous mutation of two adjacent bases. The synonymous
changes in these codons also cannot be explained by a shift to a more preferred
codon following a replacement substitution. We, therefore, interpret the excess
of double codon substitutions within a lineage as being the result of relaxed
constraints on both kinds of substitutions in particular codons.
PMID- 9755208
TI - Genetic variation and differentiation at microsatellite loci in Drosophila
simulans. Evidence for founder effects in new world populations.
AB - Drosophila simulans isofemale lines from Africa, South America, and two locations
in North America were surveyed for variation at 16 microsatellite loci on the X,
second, and third chromosomes, and 18 microsatellites, which are unmapped. D.
simulans is thought to have colonized New World habitats only relatively recently
(within the last few hundred years). Consistent with a founder effect occurring
as colonizers moved into these New World habitats, we find less microsatellite
variability in North and South American D. simulans populations than for an
African population. Population subdivision as measured at microsatellites is
moderate when averaged across all loci (FST = 0.136), but contrasts sharply with
previous studies of allozyme variation, which have showed significantly less
differentiation in D. simulans than in D. melanogaster. There are substantially
fewer private alleles observed in New World populations of D. simulans than seen
in a similar survey of D. melanogaster. In addition to possible differences in
population size during their evolutionary histories, varying colonization
histories or other demographic events may be necessary to explain discrepancies
in the patterns of variation observed at various genetic markers between these
closely related species.
PMID- 9755210
TI - Multiple origins of cytologically identical chromosome inversions in the
Anopheles gambiae complex.
AB - For more than 60 years, evolutionary cytogeneticists have been using naturally
occurring chromosomal inversions to infer phylogenetic histories, especially in
insects with polytene chromosomes. The validity of this method is predicated on
the assumption that inversions arise only once in the history of a lineage, so
that sharing a particular inversion implies shared common ancestry. This
assumption of monophyly has been generally validated by independent data. We
present the first clear evidence that naturally occurring inversions, identical
at the level of light microscopic examination of polytene chromosomes, may not
always be monophyletic. The evidence comes from DNA sequence analyses of regions
within or very near the breakpoints of an inversion called the 2La that is found
in the Anopheles gambiae complex. Two species, A. merus and A. arabiensis, which
are fixed for the "same" inversion, do not cluster with each other in a
phylogenetic analysis of the DNA sequences within the 2La. Rather, A. merus 2La
is most closely related to strains of A. gambiae homozygous for the 2L+. A.
gambiae and A. merus are sister taxa, the immediate ancestor was evidently
homozygous 2L+, and A. merus became fixed for an inversion cytologically
identical to that in A. arabiensis. A. gambiae is polymorphic for 2La/2L+, and
the 2La in this species is nearly identical at the DNA level to that in A.
arabiensis, consistent with the growing evidence that introgression has or is
occurring between these two most important vectors of malaria in the world. The
parallel evolution of the "same" inversion may be promoted by the presence of
selectively important genes within the breakpoints.
PMID- 9755211
TI - Deletion mapping of the head tilt (het) gene in mice: a vestibular mutation
causing specific absence of otoliths.
AB - Head tilt (het) is a recessive mutation in mice causing vestibular dysfunction.
Homozygotes display abnormal responses to position change and linear acceleration
and cannot swim. However, they are not deaf. het was mapped to the proximal
region of mouse chromosome 17, near the T locus. Here we report anatomical
characterization of het mutants and high resolution mapping using a set of
chromosome deletions. The defect in het mutants is limited to the utricle and
saccule of the inner ear, which completely lack otoliths. The unique specificity
of the het mutation provides an opportunity to better understand the development
of the vestibular system. Complementation analyses with a collection of embryonic
stem (ES)- and germ cell-induced deletions localized het to an interval near the
centromere of chromosome 17 that was indivisible by recombination mapping. This
approach demonstrates the utility of chromosome deletions as reagents for mapping
and characterizing mutations, particularly in situations where recombinational
mapping is inadequate.
PMID- 9755209
TI - A screen to identify Drosophila genes required for integrin-mediated adhesion.
AB - Drosophila integrins have essential adhesive roles during development, including
adhesion between the two wing surfaces. Most position-specific integrin mutations
cause lethality, and clones of homozygous mutant cells in the wing do not adhere
to the apposing surface, causing blisters. We have used FLP-FRT induced mitotic
recombination to generate clones of randomly induced mutations in the F1
generation and screened for mutations that cause wing blisters. This phenotype is
highly selective, since only 14 lethal complementation groups were identified in
screens of the five major chromosome arms. Of the loci identified, 3 are PS
integrin genes, 2 are blistered and bloated, and the remaining 9 appear to be
newly characterized loci. All 11 nonintegrin loci are required on both sides of
the wing, in contrast to integrin alpha subunit genes. Mutations in 8 loci only
disrupt adhesion in the wing, similar to integrin mutations, while mutations in
the 3 other loci cause additional wing defects. Mutations in 4 loci, like the
strongest integrin mutations, cause a "tail-up" embryonic lethal phenotype, and
mutant alleles of 1 of these loci strongly enhance an integrin mutation. Thus
several of these loci are good candidates for genes encoding cytoplasmic proteins
required for integrin function.
PMID- 9755212
TI - Molecular evolution of an imprinted gene: repeatability of patterns of evolution
within the mammalian insulin-like growth factor type II receptor.
AB - The repeatability of patterns of variation in Ka/Ks and Ks is expected if such
patterns are the result of deterministic forces. We have contrasted the molecular
evolution of the mammalian insulin-like growth factor type II receptor (Igf2r) in
the mouse-rat comparison with that in the human-cow comparison. In so doing, we
investigate explanations for both the evolution of genomic imprinting and for Ks
variation (and hence putatively for mutation rate evolution). Previous analysis
of Igf2r, in the mouse-rat comparison, found Ka/Ks patterns that were suggested
to be contrary to those expected under the conflict theory of imprinting. We find
that Ka/Ks variation is repeatable and hence confirm these patterns. However, we
also find that the molecular evolution of Igf2r signal sequences suggests that
positive selection, and hence conflict, may be affecting this region. The
variation in Ks across Igf2r is also repeatable. To the best of our knowledge
this is the first demonstration of such repeatability. We consider three
explanations for the variation in Ks across the gene: (1) that it is the result
of mutational biases, (2) that it is the result of selection on the mutation
rate, and (3) that it is the product of selection on codon usage. Explanations 2
and 3 predict a Ka-Ks correlation, which is not found. Explanation 3 also
predicts a negative correlation between codon bias and Ks, which is also not
found. However, in support of explanation 1 we do find that in rodents the rate
of silent C --> T mutations at CpG sites does covary with Ks, suggesting that
methylation-induced mutational patterns can explain some of the variation in Ks.
We find evidence to suggest that this CpG effect is due to both variation in CpG
density, and to variation in the frequency with which CpGs mutate. Interestingly,
however, a GC4 analysis shows no covariance with Ks, suggesting that to eliminate
methyl-associated effects CpG rates themselves must be analyzed. These results
suggest that, in contrast to previous studies of intragenic variation, Ks
patterns are not simply caused by the same forces responsible for Ka/Ks
correlations.
PMID- 9755214
TI - Speciation and domestication in maize and its wild relatives: evidence from the
globulin-1 gene.
AB - The grass genus Zea contains the domesticate maize and several wild taxa
indigenous to Central and South America. Here we study the genetic consequences
of speciation and domestication in this group by sampling DNA sequences from four
taxa-maize (Zea mays ssp. mays), its wild progenitor (Z. mays ssp. parviglumis),
a more distant species within the genus (Z. luxurians), and a representative of
the sister genus (Tripsacum dactyloides). We sampled a total of 26 sequences from
the glb1 locus, which encodes a nonessential seed storage protein. Within the Zea
taxa sampled, the progenitor to maize contains the most sequence diversity. Maize
contains 60% of the level of genetic diversity of its progenitor, and Z.
luxurians contains even less diversity (32% of the level of diversity of Z. mays
ssp. parviglumis). Sequence variation within the glb1 locus is consistent with
neutral evolution in all four taxa. The glb1 data were combined with adh1 data
from a previous study to make inferences about the population genetic histories
of these taxa. Comparisons of sequence data between the two morphologically
similar wild Zea taxa indicate that the species diverged approximately 700, 000
years ago from a common ancestor of intermediate size to their present
populations. Conversely, the domestication of maize was a recent event that could
have been based on a very small number of founding individuals. Maize retained a
substantial proportion of the genetic variation of its progenitor through this
founder event, but diverged rapidly in morphology.
PMID- 9755213
TI - Genetic variation and phylogeography of central Asian and other house mice,
including a major new mitochondrial lineage in Yemen.
AB - The mitochondrial DNA (mtDNA) control region and flanking tRNAs were sequenced
from 76 mice collected at 60 localities extending from Egypt through Turkey,
Yemen, Iran, Afghanistan, Pakistan, and Nepal to eastern Asia. Segments of the Y
chromosome and of a processed p53 pseudogene (Psip53) were amplified from many of
these mice and from others collected elsewhere in Eurasia and North Africa. The
251 mtDNA types, including 54 new ones reported here, now identified from
commensal house mice (Mus musculus group) by sequencing this segment can be
organized into four major lineages-domesticus, musculus, castaneus, and a new
lineage found in Yemen. Evolutionary tree analysis suggested the domesticus
mtDNAs as the sister group to the other three commensal mtDNA lineages and the
Yemeni mtDNAs as the next oldest lineage. Using this tree and the phylogeographic
approach, we derived a new model for the origin and radiation of commensal house
mice whose main features are an origin in west-central Asia (within the present
day range of M. domesticus) and the sequential spreading of mice first to the
southern Arabian Peninsula, thence eastward and northward into south-central
Asia, and later from south-central Asia to north-central Asia (and thence into
most of northern Eurasia) and to southeastern Asia. Y chromosomes with and
without an 18-bp deletion in the Zfy-2 gene were detected among mice from Iran
and Afghanistan, while only undeleted Ys were found in Turkey, Yemen, Pakistan,
and Nepal. Polymorphism for the presence of a Psip53 was observed in Georgia,
Iran, Turkmenistan, Afghanistan, and Pakistan. Sequencing of a 128-bp Psip53
segment from 79 commensal mice revealed 12 variable sites and implicated >/=14
alleles. The allele that appeared to be phylogenetically ancestral was
widespread, and the greatest diversity was observed in Turkey, Afghanistan,
Pakistan, and Nepal. Two mice provided evidence for a second Psip53 locus in some
commensal populations.
PMID- 9755215
TI - Organization and expression of the mitochondrial genome in the Nicotiana
sylvestris CMSII mutant.
AB - Previous analyses suggested that the Nicotiana sylvestris CMSII mutant carried a
large deletion in its mitochondrial genome. Here, we show by cosmid mapping that
the deletion is 60 kb in length and contains several mitochondrial genes or ORFs,
including the complex I nad7 gene. However, due to the presence of large
duplications in the progenitor mitochondrial genome, the only unique gene that
appears to be deleted is nad7. RNA gel blot data confirm the absence of nad7
expression, strongly suggesting that the molecular basis for the CMSII abnormal
phenotype, poor growth and male sterility, is the altered complex I structure.
The CMSII mitochondrial genome appears to consist essentially of one of two
subgenomes resulting from recombination between direct short repeats. In the
progenitor mitochondrial genome both recombination products are detected by PCR
and, reciprocally, the parental fragments are detected at the substoichiometric
level in the mutant. The CMSII mtDNA organization has been maintained through six
sexual generations.
PMID- 9755216
TI - A high-resolution linkage map of the citrus tristeza virus resistance gene region
in Poncirus trifoliata (L.) Raf.
AB - Resistance to citrus tristeza virus (CTV) was evaluated in 554 progeny of 10
populations derived from Poncirus trifoliata. A dominant gene (Ctv) controlled
CTV resistance in P. trifoliata. Twenty-one dominant PCR-based DNA markers were
identified as linked to Ctv by bulked segregant analysis. Of the 11 closest
markers to Ctv, only 2 segregated in all populations. Ten of these markers were
cloned and sequenced, and codominant RFLP markers were developed. Seven RFLP
markers were then evaluated in 10 populations. Marker orders were consistent in
all linkage maps based on data of single populations or on combined data of
populations with similar segregation patterns. In a consensus map, the six
closest marker loci spanned 5.3 cM of the Ctv region. Z16 cosegregated with Ctv.
C19 and AD08 flanked Ctv at distances of 0.5 and 0.8 cM, respectively. These 3
markers were present as single copies in the Poncirus genome, and could be used
directly for bacterial artificial chromosome library screening to initiate a walk
toward Ctv. BLAST searches of the GenBank database revealed high sequence
similarities between 2 markers and known plant disease resistance genes,
indicating that a resistance gene cluster exists in the Ctv region in P.
trifoliata.
PMID- 9755217
TI - Epigenetic allelic states of a maize transcriptional regulatory locus exhibit
overdominant gene action.
AB - Using alleles of the maize purple plant locus (pl), which encodes a
transcriptional regulator of anthocyanin pigment synthesis, we describe a case of
single-locus heterosis, or overdominance, where the heterozygote displays a
phenotype that is greater than either homozygote. The Pl-Rhoades (Pl-Rh) allele
is subject to epigenetic changes in gene expression, resulting in quantitatively
distinct expression states. Allelic states with low-expression levels, designated
Pl'-mahogany (Pl'-mah), are dominant to the high-expression state of Pl-Rh. Pl'
mah states retain low-expression levels in subsequent generations when homozygous
or heterozygous with Pl-Rh. However, Pl'-mah alleles frequently exhibit higher
expression levels when heterozygous with other pl alleles; illustrating an
overdominant allelic relationship. Higher expression levels are also observed
when Pl'-mah is hemizygous. These results suggest that persistent allelic
interactions between Pl'-mah and Pl-Rh are required to maintain the low
expression state and that other pl alleles are missing sequences required for
this interaction. The Pl-Rh state can be sexually transmitted from Pl'-mah/pl
heterozygotes, but not from Pl'-mah hemizygotes, suggesting that fixation of the
high-expression state may involve synapsis. The existence of such allele
dependent regulatory mechanisms implicates a novel importance of allele
polymorphisms in the genesis and maintenance of genetic variation.
PMID- 9755218
TI - Identification of trait-improving quantitative trait loci alleles from a wild
rice relative, Oryza rufipogon.
AB - Wild species are valued as a unique source of genetic variation, but they have
rarely been used for the genetic improvement of quantitative traits. To identify
trait-improving quantitative trait loci (QTL) alleles from exotic species, an
accession of Oryza rufipogon, a relative of cultivated rice, was chosen on the
basis of a genetic diversity study. An interspecific BC2 testcross population
(V20A/O. rufipogon//V20B///V20B////Ce64) consisting of 300 families was evaluated
for 12 agronomically important quantitative traits. The O. rufipogon accession
was phenotypically inferior for all 12 traits. However, transgressive segregants
that outperformed the original elite hybrid variety, V20A/Ce64, were observed for
all traits examined. A set of 122 RFLP and microsatellite markers was used to
identify QTL. A total of 68 significant QTL were identified, and of these, 35
(51%) had beneficial alleles derived from the phenotypically inferior O.
rufipogon parent. Nineteen (54%) of these beneficial QTL alleles were free of
deleterious effects on other characters. O. rufipogon alleles at two QTL on
chromosomes 1 and 2 were associated with an 18 and 17% increase in grain yield
per plant, respectively, without delaying maturity or increasing plant height.
This discovery suggests that the innovative use of molecular maps and markers can
alter the way geneticists utilize wild and exotic germplasm.
PMID- 9755220
TI - Analysis of population structure in autotetraploid species.
AB - Population structure parameters commonly used for diploid species are reexamined
for the particular case of tetrasomic inheritance (autotetraploid species).
Recurrence equations that describe the evolution of identity probabilities for
neutral genes in an "island model" of population structure are derived assuming
tetrasomic inheritance. The expected equilibrium value of FST is computed. In
contrast to diploids, the correlation of genes between individuals within
populations with respect to genes between populations (FST) may vary among loci
due to the particular segregation patterns expected under tetrasomic inheritance
and is consequently inappropriate for estimating demographic parameters in such
populations. We thus define a new parameter (rho) and derive its relationship
with Nm. This relationship is shown to be independent from both the selfing rate
and the proportion of double reduction. Finally, the statistical procedure
required to evaluate these parameters using data on gene frequencies distribution
among autotetraploid populations is developed.
PMID- 9755219
TI - Should we expect substitution rate to depend on population size?
AB - The rate of nucleotide substitution is generally believed to be a decreasing
function of effective population size, at least for nonsynonymous substitutions.
This view was originally based on consideration of slightly deleterious mutations
with a fixed distribution of selection coefficients. A realistic model must
include the occurrence and fixation of some advantageous mutations that
compensate for the loss of fitness due to deleterious substitutions. Some such
models, such as so-called "fixed" models, also predict a population size effect
on substitution rate. An alternative model, presented here, predicts the near
absence of a population size effect on substitution rate. This model is based on
concave log-fitness functions and a fixed distribution of mutational effects on
the selectively important trait. Simulations of an instance of the model confirm
the approximate insensitivity of the substitution rate to population size.
Although much experimental evidence has been claimed to support the existence of
a population size effect, the body of evidence as a whole is equivocal, and much
of the evidence that is supposed to demonstrate such an effect would also suggest
that it is very small. Perhaps the proposed model applies well to some genes and
not so well to others, and genes therefore vary with regard to the population
size effect.
PMID- 9755221
TI - A nonparametric bootstrap method for testing close linkage vs. pleiotropy of
coincident quantitative trait loci.
AB - A novel method using the nonparametric bootstrap is proposed for testing whether
a quantitative trait locus (QTL) at one chromosomal position could explain
effects on two separate traits. If the single-QTL hypothesis is accepted,
pleiotropy could explain the effect on two traits. If it is rejected, then the
effects on two traits are due to linked QTLs. The method can be used in
conjunction with several QTL mapping methods as long as they provide a
straightforward estimate of the number of QTLs detectable from the data set. A
selection step was introduced in the bootstrap procedure to reduce the
conservativeness of the test of close linkage vs. pleiotropy, so that the
erroneous rejection of the null hypothesis of pleiotropy only happens at a
frequency equal to the nominal type I error risk specified by the user. The
approach was assessed using computer simulations and proved to be relatively
unbiased and robust over the range of genetic situations tested. An example of
its application on a real data set from a saline stress experiment performed on a
recombinant population of wheat (Triticum aestivum L. ) doubled haploid lines is
also provided.
PMID- 9755222
TI - Characterization of deleterious mutations in outcrossing populations.
AB - Deng and Lynch recently proposed estimating the rate and effects of deleterious
genomic mutations from changes in the mean and genetic variance of fitness upon
selfing/outcrossing in outcrossing/highly selfing populations. The utility of our
original estimation approach is limited in outcrossing populations, since selfing
may not always be feasible. Here we extend the approach to any form of inbreeding
in outcrossing populations. By simulations, the statistical properties of the
estimation under a common form of inbreeding (sib mating) are investigated under
a range of biologically plausible situations. The efficiencies of different
degrees of inbreeding and two different experimental designs of estimation are
also investigated. We found that estimation using the total genetic variation in
the inbred generation is generally more efficient than employing the genetic
variation among the mean of inbred families, and that higher degree of inbreeding
employed in experiments yields higher power for estimation. The simulation
results of the magnitude and direction of estimation bias under variable or
epistatic mutation effects may provide a basis for accurate inferences of
deleterious mutations. Simulations accounting for environmental variance of
fitness suggest that, under full-sib mating, our extension can achieve reasonably
well an estimation with sample sizes of only approximately 2000-3000.
PMID- 9755223
TI - Dietary fat and alcoholic liver disease.
PMID- 9755224
TI - Cryptosporidium parvum is cytopathic for cultured human biliary epithelia via an
apoptotic mechanism.
AB - While the clinical features of sclerosing cholangitis secondary to opportunistic
infections of the biliary tree in patients with acquired immunodeficiency
syndrome (AIDS) are well known, the mechanisms by which microbial pathogens such
as Cryptosporidium parvum associated with this syndrome actually cause disease
are obscure. We established an in vitro model of biliary cryptosporidiosis
employing a human biliary epithelial cell line. Using morphological and
biochemical techniques, we examined the interaction of C. parvum with cultured
human cholangiocytes. When the apical plasma membrane of polarized, confluent
monolayers of human biliary epithelial cells was exposed to C. parvum oocysts
that had been excysted in vitro, sporozoites attached to and invaded the cells in
a time-, dose-, temperature-, and pH-dependent manner. The infectious process was
both plasma membrane domain- and cell-specific, because no attachment or invasion
occurred when the basolateral membrane of cholangiocytes was exposed to the
parasite, or when a human hepatocyte cell line (HepG2) was used. Time-lapse video
microscopy and scanning electron microscopy (SEM) showed that sporozoite
attachment was rapid, involved extensive cholangiocyte membrane ruffling, and
culminated in parasite penetration into a tight-fitting vacuole formed by
invagination of the plasma membrane similar to those found in naturally occurring
infection in vivo. Transmission electron microscopy (TEM) showed that C. parvum
organisms formed parasitophorus vacuoles and were able to undergo a complete
reproductive cycle, forming both asexual and sexual reproductive stages.
Unexpectedly, direct cytopathic effects were noted in infected monolayers, with
widespread programmed cell death (i.e., apoptosis) of biliary epithelial cells as
assessed both morphologically and biochemically beginning within hours after
exposure to the organism. The novel finding of specific cytopathic invasion of
biliary epithelia by C. parvum may be relevant to the pathogenesis and possible
therapy of the secondary sclerosing cholangitis seen in AIDS patients with
biliary cryptosporidiosis.
PMID- 9755225
TI - Purinergic regulation of acid/base transport in human and rat biliary epithelial
cell lines.
AB - Biliary epithelial cells (cholangiocytes) are responsible for rapid regulation of
bile volume and alkalinity. Secretin and other hormones raising intracellular
cyclic adenosine monophosphate (cAMP) concentrations promote biliary HCO3
secretion by stimulating apical Cl- channels and Cl-/HCO3- exchange (AE2).
Cholangiocyte ion transport may also be stimulated by locally acting mediators;
for example, adenosine 5'-triphosphate (ATP), a secretagogue that can be released
into the bile by hepatocytes and cholangiocytes, activates Cl- conductances and
Na+/H+ exchange (NHE) in cholangiocyte cell lines. To further explore the role of
extracellular ATP in the paracrine regulation of carrier mechanisms regulating
cholangiocyte H+/HCO3- secretion, we investigated the effects of nucleotides on
intracellular pH regulation (measured by microfluorimetry with 2'7'-bis(2
carboxyethyl)-5,6,carboxyfluorescein [BCECF]) in human (MZ-ChA-1) and rat (NRC-1)
cholangiocyte cell lines. In MZ-ChA-1 cells, 10 mol/L ATP, uridine 5'
triphosphate (UTP), and ATPgammas significantly increased NHE activity. The
pharmacological profile of agonists was consistent with that anticipated for
receptors of the P2Y2 class. ATP did not increase AE2 activity, but, when given
to cells pretreated with agents raising intracellular cAMP, had a synergistic
stimulatory effect that was inhibited by amiloride. To assess the polarity of
purinergic receptors, monolayers of NRC-1 cells were exposed to apical or
basolateral nucleotides. Apical administration of purinergic agonists, but not
adenosine, increased basolateral NHE activity (ATPgammaS > UTP > ATP).
Basolateral administration of purinergic agonists induced a weaker activation of
NHE, which was instead strongly stimulated by adenosine and by adenosine receptor
agonists (NECA = R-PIA = S-PIA). In conclusion, this study demonstrates that,
consistent with the proposed role for biliary ATP in paracrine and autocrine
control of cholangiocyte ion secretion, extracellular ATP stimulates
cholangiocyte basolateral NHE activity through P2Y2 receptors that are
predominantly expressed at the apical cell membrane.
PMID- 9755226
TI - Risk of liver and other types of cancer in patients with cirrhosis: a nationwide
cohort study in Denmark.
AB - Cancer risk in patients with cirrhosis could be modified by factors such as
changes in hormonal levels, impaired metabolism of carcinogens, or alteration of
immunological status. We investigated the risk of liver and various forms of
cancer in patients with cirrhosis in a follow-up study. We identified 11,605 1
year survivors of cirrhosis from the files of the Danish National Registry of
Patients (NRP) from 1977 to 1989. Occurrence of cancer through 1993 was
determined by linkage to the Danish Cancer Registry. For comparison, the expected
number of cancer cases was estimated from national age-, sex-, and site-specific
incidence rates. Overall, 1,447 cancers were diagnosed among the study subjects,
as compared with 708.1 expected, to yield a standardized incidence ratio (SIR) of
2.0 (95% CI: 1.9 to 2.2). In all diagnostic subgroups of cirrhosis, the risk of
primary liver cancer, mainly hepatocellular carcinoma, was markedly elevated,
with 245 observed cases and an overall 36-fold elevated risk (59.9-fold elevated
for hepatocellular carcinoma and 10-fold for cholangiocarcinoma). Substantial and
persistent excesses during follow-up were seen for all types of cancer associated
with tobacco and alcohol habits (cancer of the lung, larynx, buccal cavity,
pharynx, pancreas, urinary bladder, and kidney), while moderate excesses were
seen for cancers of the colon and breast. The latter, however, were not
complemented by any decrease in the risk of prostate cancer (SIR: 1.0; 95% CI:
0.7 to 1. 3). A slightly increased risk was seen for testis cancer, but
disappeared after 10 years. We found evidence of an increased risk for liver and
several extrahepatic cancers in patients with cirrhosis. Although part of this
increase is likely attributable to alcohol and tobacco consumption, our study
opens up the possibility that cirrhosis plays a role in the carcinogenesis of
types of cancer other than liver cancer.
PMID- 9755227
TI - Endothelial dysfunction and decreased production of nitric oxide in the
intrahepatic microcirculation of cirrhotic rats.
AB - Increased intrahepatic resistance in cirrhotic livers is in part caused by
increased vascular tone. Several morphological abnormalities have been described
in the sinusoidal endothelial cells of cirrhotic livers, but the functional
impact of these abnormalities on the intrahepatic vascular tone has not been
studied. The aim of this study was to investigate the intrahepatic endothelial
function and the role of nitric oxide (NO) with regard to vascular tone in
cirrhotic livers. Isolated rat liver perfusions were performed in cirrhotic rats
(induced by chronic carbon tetrachloride inhalation) and weight-matched normal
controls. After preconstricting the intrahepatic microcirculation with
methoxamine (10(-4) mol/L), response to cumulative doses of receptor-mediated
endothelial agonist, acetylcholine (10(-7) mol/L-10(-5) mol/L), was obtained. In
another series, response to the receptor-independent endothelial agonist, calcium
ionophore A23187 (10(-7) mol/L and 3 x 10(-7) mol/L), was obtained in the absence
and presence of Nomega-nitro-L-arginine (NNA) and indomethacin. In a third series
of rats, nitrate and nitrite production was measured in the perfusate of perfused
normal and cirrhotic livers. There was significantly less vasorelaxation in
cirrhotic livers as compared with normal livers in response to acetylcholine and
calcium ionophore A23187 (P < .0001). The impaired vasorelaxation was a result of
a decrease in both NO-mediated and non-NO-mediated components of vasorelaxation.
Cirrhotic livers from ascitic rats had significantly less vasorelaxation as
compared with livers from nonascitic rats (P < .005). There was significantly
less production of nitrates and nitrites in cirrhotic livers (P < .05). The liver
microcirculation of cirrhotic livers is characterized by endothelial dysfunction
that results in impaired release of endothelial relaxing factors including NO.
PMID- 9755228
TI - Doppler study of mesenteric, hepatic, and portal circulation in alcoholic
cirrhosis: relationship between quantitative Doppler measurements and the
severity of portal hypertension and hepatic failure.
AB - To determine the relationship between quantitative Doppler parameters of portal,
hepatic, and splanchnic circulation and hepatic venous pressure gradient (HVPG),
variceal size, and Child-Pugh class in patients with alcoholic cirrhosis, we
studied forty patients with proved alcoholic cirrhosis who underwent Doppler
ultrasonography, hepatic vein catheterization, and esophagoscopy. The following
Doppler parameters were recorded: time-averaged mean blood velocity, volume flow
of the main portal vein flow, and resistance index (RI) of the hepatic and of the
superior mesenteric artery. Doppler findings were compared with HVPG, presence
and size of esophageal varices, and Child-Pugh class. There was a significant
inverse correlation between portal velocity and HVPG (r = -.69), as well as
between portal vein flow and HVPG (r = -.58). No correlation was found between RI
in the hepatic artery or superior mesenteric artery and HVPG. No correlation was
found between portal vein measurements and presence and size of varices. Severe
liver failure was associated with lower portal velocity and flow. In patients
with alcoholic cirrhosis, only portal vein blood velocity and flow, but neither
hepatic nor mesenteric artery RI, are correlated to the severity of portal
hypertension and to the severity of liver failure.
PMID- 9755229
TI - Acute effects of the oral administration of midodrine, an alpha-adrenergic
agonist, on renal hemodynamics and renal function in cirrhotic patients with
ascites.
AB - The effects of the acute administration of arterial vasoconstrictors on renal
plasma flow (RPF) and urinary sodium excretion (UNaV) in cirrhotic patients with
ascites with or without hepatorenal syndrome (HRS) are still controversial. As a
consequence, vasoconstrictors are not actually used in the treatment of renal
sodium retention or HRS in these patients, regardless of the several lines of
evidence suggesting that these renal functional abnormalities are related to a
marked arterial vasodilation. The lack of an orally available effective arterial
vasoconstrictor probably represents a further reason for this omission.
Consequently, the present study was made to evaluate the acute effects of the
oral administration of midodrine, an orally available -mimetic drug, on systemic
and renal hemodynamics and on UNaV in cirrhotic patients with ascites. Mean
arterial pressure (MAP), heart rate (HR), cardiac index (CI), systemic vascular
resistance (SVR), left forearm blood flow (LFBF), left leg blood flow (LLBF),
RPF, glomerular filtration rate (GFR), UNaV, plasma renin activity (PRA), plasma
concentration of antidiuretic hormone (ADH), and the serum levels of nitrite and
nitrate (NOx) were evaluated in 25 cirrhotic patients with ascites (17 without
HRS and 8 with type 2 HRS) before and during the 6 hours following the oral
administration of 15 mg of midodrine. During the first 3 hours after the drug
administration, a significant increase in MAP (89.6 +/- 1.7 vs. 81.80 +/- 1.3 mm
Hg; P < .0001) and SVR (1, 313.9 +/- 44.4 vs. 1,121.2 +/- 60.1 dyn . sec . cm-5;
P < .0001) accompanied by a decrease in HR (69 +/- 2 vs. 77 +/- 3 bpm; P < .005)
and CI (2,932.7 +/- 131.4 vs. 3,152.5 +/- 131.4 mL . min-1 . m2 BSA; P < .0025)
was observed in patients without HRS. No change was observed in LFBF and LLBF.
The improvement in systemic hemodynamics, which was also maintained during the
the 3- to 6-hour period after midodrine administration, was accompanied by a
significant increase in RPF (541.5 +/- 43.1 vs. 385.7 +/- 39.9 mL . min-1; P <
.005), GFR (93.1 +/- 6.5 vs. 77.0 +/- 6.7 mL . min-1; P < .025), and UNaV (92.7
+/- 16.4 vs. 72.2 +/- 10.7 microEq . min-1; P < .025). In addition, a decrease in
PRA (5.33 +/- 1.47 vs. 7.74 +/- 2.17 ng . mL-1 . h; P < .05), ADH (1.4 +/- 0.2
vs. 1.7 +/- 0.2 pg . mL-1; P < .05), and NOx (33.4 +/- 5.0 vs. 49.3 +/- 7.3
micromol-1; P < .05) was found. In patients with HRS, the effects of the drug on
the systemic hemodynamics was smaller and shorter. Accordingly, regardless of a
significant decrease in PRA (15.87 +/- 3.70 vs. 20.70 +/- 4.82 ng . mL-1 . h; P <
.0025) in patients with HRS, no significant improvement was observed in RPF, GFR,
or UNaV. In conclusion, the acute oral administration of midodrine is associated
with a significant improvement in systemic hemodynamics in nonazotemic cirrhotic
patients with ascites. As a result, renal perfusion and UNaV also improve in
these patients. By contrast, midodrine only slightly improves systemic
hemodynamics in patients with type 2 HRS, with no effect on renal hemodynamics
and renal function.
PMID- 9755230
TI - Gene expression of alpha1-6 fucosyltransferase in human hepatoma tissues: a
possible implication for increased fucosylation of alpha-fetoprotein.
AB - The 1-6 fucosylated -fetoprotein (AFP) present in serum of patients with
hepatocellular carcinoma (HCC) has been employed for the differential clinical
diagnosis of HCC from chronic liver diseases. The molecular mechanism by which
this alteration occurs, however, remains largely unknown. To address this issue,
we purified GDP-L-Fuc:N-acetyl-beta-D-glucosaminide 1-6 fucosyltransferase (1-6
FucT), an enzyme involved in the 1-6 fucosylation of N-glycans from porcine
brain, as well as from a human gastric cancer cell line, and cloned their genes.
In this study, levels of 1-6 FucT mRNA expression and the activity of this enzyme
for 12 human HCC tissues were examined and compared with that in surrounding
tissues and normal livers. The mean +/- SD for 1-6 FucT activity was 78 +/- 41
pmol/h/mg in normal control liver, 202 +/- 127 pmol/h/mg in adjacent uninvolved
liver tissues (chronic hepatitis: 181 +/- 106 pmol/h/mg; liver cirrhosis: 233 +/-
164 pmol/h/mg), and 195 +/- 72 pmol/h/mg in HCC tissues. The mRNA expression of 1
6 FucT was also enhanced in proportion to enzymatic activity except for a few
cases, suggesting that 1-6 FucT expression is increased in chronic liver
diseases, especially liver cirrhosis. Transfection of 1-6 FucT gene into cultured
rat hepatocytes markedly increased 1-6 FucT activity and led to an increase in
lens culinaris agglutinin (LCA) binding proteins in both cell lysates and
condition media. When the 1-6 FucT gene was transfected into a human HCC cell
line, Hep3B, which originally showed low levels of 1-6 FucT expression, 1-6
fucosylated AFP was dramatically increased in the condition media. Collectively,
these results suggest that the enhancement of 1-6 FucT expression increased the
fucosylation of several proteins, including AFP, and that the level of 1-6
fucosylated AFP in patients with HCC was in part caused by up-regulation of the 1
6 FucT gene expression.
PMID- 9755231
TI - Clonal analysis of macronodules in cirrhosis.
AB - Several arguments suggest that most hepatocellular carcinomas (HCCs) occurring in
human cirrhotic livers arise from large hepatocellular nodules or macronodules.
Except for nodules with obvious features of HCC, there exist no consistent
criteria enabling the differentiation between benign regenerative and neoplastic,
potentially malignant macronodules. Surrogate markers able to accurately
discriminate those lesions that will evolve toward a HCC are required. In this
study, we investigated the clonality of 26 macronodules isolated from eight cases
of explanted cirrhotic livers in women by analyzing X-chromosome inactivation, as
indicated by the methylation status of the human androgen receptor gene (HUMARA).
For each macronodule, a large set of pathological features was evaluated and used
to classify the macronodules into four groups: entirely benign-looking nodule
(type 1), low-grade dysplastic nodule (type 2), high-grade dysplastic nodule
(type 3), and HCC (type 4). Clonal analysis showed that 14 macronodules (54%)
were monoclonal and 12 (46%) were polyclonal. Monoclonality was detected in 5 of
11 (45%) nodules from groups of entirely benign-looking and low-grade dysplastic
nodules (types 1 and 2) and in 9 of 15 (60%) nodules from the group of high-grade
dysplastic nodule and HCC (types 3 and 4). Neither the etiology of cirrhosis nor
the size or histological classification of macronodules was correlated with the
clonal status. In conclusion, clonal analysis of macronodules enables the
differentiation between mono- and polyclonal macronodules in cirrhosis. Because
monoclonal macronodules are prone to evolve to HCC, the determination of the
clonal status of a macronodule could provide additional information for
evaluating the prognosis of these lesions.
PMID- 9755232
TI - Analysis of liver regeneration in mice lacking type 1 or type 2 tumor necrosis
factor receptor: requirement for type 1 but not type 2 receptor.
AB - We used KO mice lacking either TNF receptor 1 (TNFR-1) or receptor 2 (TNFR-2) to
determine whether signaling at the start of liver regeneration after partial
hepatectomy (PH) involves only one or both TNF receptors and to analyze in more
detail the abnormalities caused by lack of TNFR-1 receptor, which is required for
the initiation of liver regeneration. Lack of TNFR-2 had little effect on NF
kappaB and STAT3 binding, and no effect in interleukin-6 production after PH, but
caused a delay in AP-1 and C/EBP binding and in the expression of c-jun and c-myc
messenger RNA (mRNA). In contrast to mice lacking TNFR-1, which had deficient
hepatocyte DNA synthesis and massive lipid accumulation in hepatocytes, TNFR-2 KO
mice had normal liver structure and similar levels of hepatocyte DNA replication
as those of wild type mice. We conclude that TNFR-1, but not TNFR-2, is necessary
for liver regeneration, and that NF-kappaB and STAT3 binding are activated by
signals transduced by TNFR-1. Inhibition of AP-1 and C/EBP binding and in the
expression of c-jun and c-myc mRNA in the first 4 hours after PH, as well as the
apparent lack of Fos in AP-1 complexes, had no effect on the timing or extent of
DNA replication.
PMID- 9755233
TI - Clinical relevance of transforming growth factor alpha, epidermal growth factor
receptor, p53, and Ki67 in colorectal liver metastases and corresponding primary
tumors.
AB - To determine whether the expression of transforming growth factor alpha (TGF
alpha), its receptor (epidermal growth factor receptor [EGFr]), p53 nuclear
protein, and proliferation influences prognosis of patients with liver
metastases, a study was performed in 45 liver metastases and 33 corresponding
primary colorectal carcinomas in patients referred for liver surgery. The
expression of TGF-alpha, EGFr, p53 nuclear protein, and proliferation rate was
correlated with clinicopathological characteristics and survival after partial
liver resection. In liver metastases, TGF-alpha expression was low in 42%,
intermediate in 35%, and high in 23%. TGF-alpha expression was higher in liver
metastases derived from lymph node-positive primary carcinomas, in synchronous
and in irresectable liver metastases compared with those derived from lymph node
negative primary carcinomas, metachronous, and resectable liver metastases.
Nuclear p53 expression was found in 83% of primary tumors and 71% of liver
metastases. p53 expression did not correlate with the various clinicopathological
characteristics. Ki67 expression was not associated with clinicopathological
characteristics in primary and metastatic tumors. In the 38 patients in whom a
partial liver resection was performed, median survival was 25 months in patients
with a higher TGF-alpha expression in the metastasis than in the primary tumor
and 60 months in patients with comparable or lower TGF-alpha expression in the
metastasis than in the primary tumor (P = .036). Median survival after liver
resection was 21 months in patients with p53-negative liver metastases and 58
months in patients with p53-positive metastases (P = .043). By multivariate
analysis, p53 and EGFr expression on liver metastases were the best predictors of
disease-free survival after partial liver resection, with relative risks of 2.38
and 3.33, respectively. In patients with colorectal liver metastases, referred
for liver surgery, a higher TGF-alpha expression is associated with unfavorable
tumor characteristics, whereas p53 and absence of EGFr expression is associated
with a better survival after partial liver resection.
PMID- 9755234
TI - Immunolocalization of OV-6, a putative progenitor cell marker in human fetal and
diseased pediatric liver.
AB - The existence of progenitor (stem) cells in the human liver remains a matter of
debate. In rodent models of hepatocarcinogenesis and injury, oval cells
proliferate in the periportal regions of the portal tracts and are suggested to
derive from a stem cell compartment, because they are capable of differentiating
into hepatocytes or biliary epithelial cells. In this study, the rat oval cell
marker, OV-6 has been used to investigate the hypothesis that there are stem
cells present in fetal and pediatric human liver. The pattern of OV-6 expression
was compared with the established adult biliary cell markers human epithelial
antigen-125 (HEA-125) and cytokeratin-19 (CK-19). In normal pediatric liver (n =
7), bile ducts and ductules were immunostained with CK-19 and HEA-125, whereas OV
6 staining was consistently negative. In fetal tissue (n = 10), ductal plate
cells, primitive bile ducts, and hepatoblasts were stained with CK-19 and HEA-125
although only some of the ductal plate cells and hepatoblasts were OV-6 positive.
In biliary atresia (n = 6) and 1, anti-trypsin deficiency (1,AT) (n = 4), CK-19
and HEA-125 immunostained ductular proliferative cells that tended to form finely
anastomosing ductules, whereas OV-6 staining was found more on discrete cells
confined to portal tract margins. Additionally, in diseased liver, OV-6 was
strongly positive in hepatocyte lobules with greatest intensity in the periseptal
regions. This widespread hepatocyte OV-6 positivity suggests that the antibody
may identify cells of a less differentiated phenotype (transitional hepatocytes)
that have replaced the mature cells. Therefore, it is proposed that in human
liver, OV-6 is recognizing cells with a progenitor stem cell-like phenotype with
the capacity to differentiate into OV-6 positive ductular cells or lobular
hepatocytes.
PMID- 9755236
TI - Interaction between heat shock and interleukin 6 stimulation in the acute-phase
response of human hepatoma (HepG2) cells.
AB - Two characteristic elements of the acute-phase response are an altered pattern of
circulating hepatic proteins and fever. Whereas a fever-induced heat shock
response could affect expression of acute-phase proteins in the liver, the
effects of a modest temperature increase on protein secretion in interleukin-6
(IL-6)-stimulated HepG2 cells were investigated. The response of HepG2 cells to
IL-6 stimulation was significantly affected by heat treatment at 40 degreesC.
Albumin secretion rates, which were reduced by a factor of 2 in response to
either heat shock or IL-6 stimulation alone, were down-regulated by a factor of 4
when IL-6 was administered simultaneously with a continuous 40 degrees C heat
shock. IL-6-induced fibrinogen up-regulation was significantly reduced by heat
treatment (P < .01), and secretion rates were indistinguishable from control
levels after 2 days (P > .10). Unexpectedly, heat shock at 40 degrees C induced a
fivefold up-regulation of haptoglobin production in the absence of IL-6.
Simultaneous heat shock and IL-6 stimulation caused a synergistic enhancement of
haptoglobin expression, with secretion rates increasing up to 30-fold compared
with unstimulated control cells. For all three proteins, the interaction between
temperature and IL-6 concentration was statistically significant (P < .001). Heat
treatment resulted in significant alterations of both the kinetics and
sensitivity of IL-6-induced protein synthesis, suggesting a major modification of
the mechanism of acute-phase protein regulation at 40 degreesC. In summary, the
data show that heat shock can significantly modulate the pattern of acute-phase
protein expression and that fever may be an important regulatory factor in the
acute-phase response.
PMID- 9755235
TI - Expression of human macrophage metalloelastase gene in hepatocellular carcinoma:
correlation with angiostatin generation and its clinical significance.
AB - Macrophage metalloelastase, a member of the human matrix metalloproteinase
family, is believed to play an important role in angiostatin generation, which,
in experimental studies, has an antiangiogenic function and is a key molecule in
tumor dormancy. However, no clinical studies have been reported regarding the
correlation between human macrophage metalloelastase (HME) gene expression and
angiostatin production. Therefore, the present study was designed to evaluate the
HME messenger RNA (mRNA) expression and angiostatin generation in hepatocellular
carcinoma (HCC). Tumorous and contiguous nontumorous tissues were obtained from
40 HCC patients who underwent curative partial hepatectomy. By using Northern
blot hybridization, HME mRNA was detected in 25 of the 40 HCC samples and, in all
of these cases, the expression in tumorous tissues was stronger than in the
nontumorous tissues. In situ hybridization identified the HCC cells as mainly
responsible for the signals shown in Northern blot. Angiostatin was detected by
Western blot mainly in tumors and showed significant association with HME mRNA
expression in tumorous tissues (P = .0008). The patients whose tumors did not
express HME mRNA and, thus, did not produce angiostatin, demonstrated poorer
survival than those whose tumors showed high expression of HME mRNA and
angiostatin generation (P = . 002). The univariate and multivariate analyses
revealed that HME mRNA expression is a new and independent variable affecting
overall survival (P = .001 and P = .03, respectively). These findings show that
the HME gene is expressed in HCC being significantly associated with angiostatin
generation by such tumors and that HME mRNA expression may serve as a new
molecular prognostic marker in HCC patients after partial hepatectomy.
PMID- 9755237
TI - Efficacy of anti-intercellular adhesion molecule-1 immunotherapy on immune
responses to allogeneic hepatocytes in mice.
AB - Adhesion molecules appear to play important roles in vascularized organ allograft
rejection, because antibodies directed against them are effective in prolonging
survival of vascularized organ allografts in rodents. However, the efficacy of
these agents for cellular allografts is unknown. The current studies were
undertaken to determine the role of intercellular adhesion molecule-1 (ICAM-1)
and vascular cell adhesion molecule-1 (VCAM-1) on host immune responses to
purified hepatocytes. Host mice (C3H, H-2(k)) grafted with hepatocytes in sponge
matrix allografts (HC-SMA) received IgG isotype control, anti-ICAM-1, or anti
VCAM-1 monoclonal antibody (mAb) on days 0 through 9 after grafting. Twelve to 14
days later, host cells infiltrating the HC-SMA were assessed for the development
of allospecific cytolytic T cells (allo-CTLs). Treatment with anti-ICAM-1 or anti
VCAM-1 mAb resulted in significantly decreased recruitment of host cells into HC
SMA (P < .035). However, only anti-ICAM-1 mAb resulted in abrogation of
development of allo-CTLs in HC-SMA (P = .001). C3H (H-2(k)) hosts grafted with
allogeneic hepatocytes from control C57BL/6 (H-2(b)) or ICAM-1 knockout [H-2(b)]
mice elicited the development of allo-CTLs in HC-SMA (P = not significant).
Furthermore, there was no difference in the development of allo-CTLs in HC-SMA of
control hosts [C57BL/6, H-2(b)] compared with ICAM-1 knockout hosts (H-2(b)) (P =
not significant). Treatment with anti-ICAM-1 mAb had no effect on the development
of allo-CTLs in ICAM-1 knockout (H-2(b)) hosts bearing HC-SMA. The
immunosuppressive effect of host treatment with anti-ICAM-1 mAb does not appear
to be a consequence of simple blockage of donor hepatocyte or host immune cell
expression of ICAM-1, but suggests a potential inhibitory effect on host immune
cell activation or function, as well as an effect on recruitment of host cells to
the allograft.
PMID- 9755238
TI - The hepatitis B virus X protein up-regulates tumor necrosis factor alpha gene
expression in hepatocytes.
AB - Human hepatocytes infected by hepatitis B virus (HBV) produce the proinflammatory
cytokine, tumor necrosis factor (TNF-). In this study, we explored the mechanism
of induction of TNF- synthesis by HBV. We found that the stable HBV-transfected
hepatoma cell line, 2. 2.15, expressed high-molecular-weight (HMW) TNF- mRNAs,
which were absent in the parent HepG2 cells. Treatment of 2.2.15 cells with
interferon alfa (IFN-) and/or interleukin-1beta (IL-1beta) reduced both viral
gene transcription and TNF- mRNA expression. Transient or stable transfection of
hepatocyte-derived cell lines with HBV X protein (HBx) expression vectors induced
the production of biologically active TNF-. In these cells, the HBx-induced TNF-
was detected both as cell-associated and soluble forms. Luciferase gene
expression assays showed that the TNF- gene promoter contained target sequences
for HBx trans-activation within the proximal region of the promoter. These
results indicate that the hepatocyte TNF- synthesis induced by HBV is
transcriptionally up-regulated by HBx. Thus, HBx may have a role in the induction
of the intrahepatic inflammatory processes that take place during acute and
chronic hepatitis B.
PMID- 9755239
TI - Ischemia/reperfusion injury in the liver of BALB/c mice activates AP-1 and
nuclear factor kappaB independently of IkappaB degradation.
AB - For many inherited and acquired hepatic diseases, liver transplantation is the
only possible therapeutic strategy. Ischemia/reperfusion (I/R) damage to donor
tissue is thought to be one component that may play a role in the decline of
posttransplant tissue function and ultimately rejection. The transcription
factors, AP-1 and nuclear factor kappaB (NF-kappaB), play important roles in the
acute cellular responses to tissue damage, as well as the inflammatory phase
following I/R. We have found that the DNA binding activity of AP-1 was
dramatically increased following warm ischemia at 1 to 3 hours postreperfusion.
Induced DNA binding activity was composed of predominately c-Jun and JunD hetero-
and homodimers as determined by electrophoretic mobility supershift assays. This
increase in AP-1 activity occurred in the absence of significant changes in the
steady-state protein levels of c-Jun and JunB. Maximal activation of Jun amino
terminal kinase ( JNK) occurred within the 25 to 30 minutes postreperfusion, just
before the peak in AP-1 DNA binding. These findings suggest that phosphorylation
may play an important role in regulating AP-1 transcriptional complexes.
Furthermore, JunD protein levels slightly increased at 3 hours postreperfusion,
concordant with changes in AP-1 DNA binding activity. The activation of NF-kappaB
at 1 hour postreperfusion was independent of proteolytic degradation of IkappaB-
or IkappaB-beta. This activation of NF-kappaB DNA binding activity in the nucleus
was preceded by an increase in tyrosine phosphorylation of IkappaB-. These
studies suggest that JNK, IkappaB tyrosine kinase, and JunD are potential targets
for therapeutic intervention during liver I/R injury.
PMID- 9755240
TI - Vasopressin-induced disruption of actin cytoskeletal organization and canalicular
function in isolated rat hepatocyte couplets: possible involvement of protein
kinase C.
AB - The effect of vasopressin (VP) on canalicular function and hepatocellular
morphology, with particular regard to actin cytoskeletal organization and the
concomitant plasma membrane bleb formation, was studied in isolated rat
hepatocyte couplets. VP induced the concentration-dependent formation of multiple
plasma membrane blebs as well as simultaneous impairment in both canalicular
vacuolar accumulation (cVA) and retention (cVR) of the fluorescent bile acid,
cholyl-lysyl-fluorescein (CLF), which evaluate couplet secretory function and
tight-junction integrity, respectively. These effects were mimicked by the
protein kinase C (PKC) activator, phorbol dibutyrate (PDB), but not by the
protein kinase A (PKA) activator, dibutyryl-cAMP. VP-induced bleb formation and
canalicular dysfunction were fully prevented by the protein kinase inhibitor, H
7, but not by the PKA inhibitor, KT5720, further suggesting a specific role of
PKC. VP-induced alterations were also prevented by pretreatment with the Ca2+
buffering agent, BAPTA/AM, but not with the calmodulin-dependent protein kinase
II antagonist, calmidazolium. Neither the Ca2+-activated neutral protease
inhibitor, leupeptin, nor the antioxidants, alpha-tocopherol or deferoxamine,
were able to prevent either VP-induced plasma membrane blebbing or canalicular
dysfunction. The Ca2+-ionophore, A23187, mimicked the VP-induced alterations, but
its harmful effects were completely prevented by H-7. Bleb formation induced by
VP and PDB was accompanied by an extensive redistribution of filamentous actin
from the pericanalicular area to the cell body, and this effect was fully
prevented by H-7. These results suggest that VP-induced canalicular and
cytoskeletal dysfunction is mediated by PKC and that classical (Ca2+-dependent)
PKC appear to be involved because intracellular Ca2+ is required for VP to induce
its harmful effects.
PMID- 9755241
TI - Dietary juniper berry oil minimizes hepatic reperfusion injury in the rat.
AB - Juniper berry oil is rich in 5,11,14-eicosatrienoic acid, a polyunsaturated fatty
acid similar to one found in fish oil, yet less prone to peroxidation. Dietary
fish oil treatment has been shown to effectively reduce reperfusion injury;
therefore, the effects of a diet containing juniper berry oil on hepatic
reperfusion injury in a low-flow, reflow reperfusion model were investigated in
the rat. Rats were fed semisynthetic diets containing either juniper berry oil,
fish oil, or corn oil for 14 to 16 days. Daily food consumption averaged around
20 g/d in both the control and treatment groups; average daily weight gain was
around 4 g per 100 g rat weight in all three groups studied, and there were no
significant differences in these parameters. Livers were initially perfused at
low-flow rates to induce pericentral hypoxia followed by a 40-minute reperfusion
period. Peak lactate dehydrogenase (LDH) release during reflow averaged 44 U/g/h
in the corn oil group and 32 U/g/h in the fish oil group, but was only 21 U/g/h
as a result of juniper berry oil treatment. Malondialdehyde (MDA), an end-product
of lipid peroxidation, reached a maximum value of 62 nmol/g/h in the corn oil
group, but only reached 43 nmol/g/h and 34 nmol/g/h in the fish oil and juniper
berry oil groups, respectively. Both juniper berry oil and fish oil treatment
improved rates of bile flow from 25 microL/g/h (corn oil) to 36 and 38
microL/g/h, respectively. Importantly, juniper berry oil reduced cell death in
pericentral regions of the liver lobule by 75%. Trypan blue distribution time, an
indicator of the hepatic microcirculation, was reduced by approximately 25% with
fish oil and over 50% by juniper berry oil diets compared with corn oil controls.
The rates of entry of fluorescein-dextran, a dye confined to the vascular space,
were increased 1.8- and 2.6-fold, and rates of outflow were increased 4.4- and
4.3-fold by fish oil and juniper berry oil, respectively, also reflecting
improved microcirculation. Juniper berry oil also blunted increases in
intracellular calcium and release of prostaglandin E2 (PGE2) by cultured Kupffer
cells stimulated by endotoxin. These results are consistent with the hypothesis
that feeding a diet containing juniper berry oil reduces reperfusion injury by
inhibiting activation of Kupffer cells, thus reducing vasoactive eicosanoid
release and improving the hepatic microcirculation in livers undergoing oxidant
stress.
PMID- 9755242
TI - Nitric oxide inactivates rat hepatic methionine adenosyltransferase In vivo by S
nitrosylation.
AB - We investigated the mechanism of nitric oxide (NO) action on hepatic methionine
adenosyltransferase (MAT) activity using S-nitrosoglutathione (GSNO) as NO donor.
Hepatic MAT plays an essential role in the metabolism of methionine, converting
this amino acid into S-adenosylmethionine. Hepatic MAT exists in two oligomeric
states: as a tetramer (MAT I) and as a dimer (MAT III) of the same subunit. This
subunit contains 10 cysteine residues. In MAT I, S-nitrosylation of 1 thiol
residue per subunit was associated with a marked inactivation of the enzyme
(about 70%) that was reversed by glutathione (GSH). In MAT III, S-nitrosylation
of 3 thiol residues per subunit led to a similar inactivation of the enzyme,
which was also reversed by GSH. Incubation of isolated rat hepatocytes with S
nitrosoglutathione monoethyl ester (EGSNO), a NO donor permeable through the
cellular membrane, induced a dose-dependent inactivation of MAT that was reversed
by removing the NO donor from the cell suspension. MAT, purified from isolated
rat hepatocytes, contained S-nitrosothiol groups and the addition of increasing
concentrations of EGSNO to the hepatocyte suspension led to a progressive S
nitrosylation of the enzyme. Removal of the NO donor from the incubation media
resulted in loss of most NO groups associated to the enzyme. Finally, induction
in rats of the production of NO, by the administration of bacterial
lipopolysaccharide (LPS), induced a fivefold increase in the S-nitrosylation of
hepatic MAT, which led to a marked inactivation of the enzyme. Thus, the activity
of liver MAT appears to be regulated in vivo by S-nitrosylation.
PMID- 9755243
TI - Increased risk of chronic liver failure in adults with heterozygous alpha1
antitrypsin deficiency.
AB - Controversy exists whether patients who are genetically heterozygous for 1
antitrypsin deficiency (1ATD), carrying a single PI*Z allele, are at increased
risk of developing chronic liver disease. In these investigations, we determined
the prevalence of heterozygous 1AT phenotypes (PI MZ, PI SZ) in a well
characterized cohort of patients presenting with chronic liver failure before
orthotopic liver transplantation (OLT). We analyzed data collected from all adult
patients (n = 641) who underwent OLT at our tertiary referral center between
March 1985 and December 1996. Study patients entered a prospective protocol
designed to test for all known etiologies of liver disease. Complete testing
including 1AT phenotyping was successfully performed in 599 adults. We compared
the overall number of heterozygous PI*Z carriers in our OLT cohort with
established prevalence figures for general and regional American populations, and
examined their distribution among various liver disease subgroups. Fifty-one
patients were found to be heterozygous carriers of a single PI*Z allele for 1AT.
The predominant phenotype in our transplantation cohort was PI MZ, identified in
49 patients (8.2%), which is a significantly higher prevalence than that reported
from previous American population studies (2%-4%). Additionally, a significantly
greater number of PI MZ carriers existed in patients with cryptogenic cirrhosis
compared with other liver disease categories (26.9%; P < .001). These data
suggest that individuals carrying a single PI*Z allele for 1AT may be at
increased risk of developing cirrhosis and liver failure, even in the absence of
an identifiable coexisting liver disease.
PMID- 9755244
TI - Cholesterol 7alpha-hydroxylase (CYP7A): patterns of messenger RNA expression
during rat liver development.
AB - Cholesterol 7-hydroxylase is a rate-limiting enzyme in bile acid synthesis, a
major pathway for cholesterol catabolism. It plays a crucial role in postnatal
development and survival. In an adult liver, its activity and messenger RNA
(mRNA) are heterogeneously distributed with concentration in the pericentral
area. We defined how the pattern of cholesterol 7-hydroxylase mRNA evolves during
rat liver development, correlated this with its total liver mRNA levels, and
determined when its heterogeneous pattern of expression is established.
Cholesterol 7-hydroxylase mRNA was undetectable in 18-day-old fetal livers by
Northern blot. It was increased markedly in newborns with a homogeneous liver
lobular distribution as determined by in situ hybridization. At postnatal day
four, mRNA levels were markedly decreased with concomitant appearance of a
lobular gradient: mRNA was detected only in a few hepatocytes located around
efferent venules. At 22 days, the time of highest mRNA expression, a marked
extension of the gradient towards the periportal area was observed, indicating
that the increase in total liver cholesterol 7-hydroxylase mRNA level was a
result of recruitment of hepatocytes upstream from the central vein area. By 28
days, the adult pattern was observed. Thus, expression of cholesterol 7
hydroxylase mRNA is tightly regulated during rat liver development, both
temporally and spatially supporting its critical role in normal postnatal
development.
PMID- 9755245
TI - Activation of protein kinase Calpha couples cell volume to membrane Cl-
permeability in HTC hepatoma and Mz-ChA-1 cholangiocarcinoma cells.
AB - Physiological increases in liver cell volume lead to an adaptive response that
includes opening of membrane Cl- channels, which is critical for volume recovery.
The purpose of these studies was to assess the potential role for protein kinase
C (PKC) as a signal involved in cell volume homeostasis. Studies were performed
in HTC rat hepatoma and Mz-ChA-1 human cholangiocarcinoma cells, which were used
as model hepatocytes and cholangiocytes, respectively. In each cell type, cell
volume increases were followed by: 1) translocation of PKC from cytosolic to
particulate (membrane) fractions; 2) a 10- to 40-fold increase in whole-cell
membrane Cl- current density; and 3) partial recovery of cell volume. In HTC
cells, the volume-dependent Cl- current response (-46 +/- 5 pA/pF) was inhibited
by down-regulation of PKC (100 nmol/L phorbol 12-myristate 13-acetate for 18
hours [PMA]; -1.97 +/- 1.5 pA/pF), chelation of cytosolic Ca2+ (2 mmol/L EGTA;
5.3 +/- 4.0 pA/pF), depletion of cytosolic adenosine triphosphate (ATP) (3 U/mL
apyrase; -12.58 +/- 1. 45 pA/pF), and by the putative PKC inhibitor,
chelerythrine (25 micromol/L; -7 +/- 3 pA/pF). In addition, PKC inhibition by
chelerythrine and calphostin C (500 nmol/L) prevented cell volume recovery from
swelling. Similar results were obtained in Mz-ChA-1 biliary cells. These findings
indicate that swelling-induced activation of PKC represents an important signal
coupling cell volume to membrane Cl- permeability in both hepatic and biliary
cell models.
PMID- 9755246
TI - Neither intestinal sequestration of bile acids nor common bile duct ligation
modulate the expression and function of the rat ileal bile acid transporter.
AB - The regulatory responses of bile acid (BA) transport in the terminal ileum to
perturbations in BA homeostasis are complex, and conflicting results have been
reported by different investigators. These studies were designed to examine the
response of this system to a reduction in ileal bile salt concentrations at both
a functional and molecular level. Common bile duct ligation (BDL) or feeding of a
novel bile acid-binding compound, GT31-104HB, for 7 days were used to reduce
ileal apical membrane bile salt flux. Apical bile acid transport function was
assessed by examining sodium-dependent uptake of [3H]-taurocholate (TC) into
brush border membrane vesicles (BBMV). Expression of the apical sodium-dependent
bile acid transporter (ASBT) and the ileal lipid-binding protein (ILBP) were
assessed by Western blotting with quantitation using [125I]-labeled secondary
antibody and a phosphorimager. Neither common BDL nor intestinal sequestration of
BA led to a change in ileal bile acid transport function or the expression of the
ASBT or the ILBP. These results indicate that a reduction in presentation of bile
salts to the apical surface of the terminal ileum does not modulate the
expression of the genes involved in their transport.
PMID- 9755247
TI - Gender-related differences in bile acid and sterol metabolism in outbred CD-1
mice fed low- and high-cholesterol diets.
AB - These studies were undertaken to determine whether in young adult outbred CD-1
mice there were any gender-related differences in basal bile acid metabolism that
might be important in determining how males and females in this species responded
to a dietary cholesterol challenge. When fed a plain cereal-based rodent diet
without added cholesterol, 3-month-old females, compared with age-matched males,
manifested a significantly larger bile acid pool (89.1 vs. 54.1 micromol/100 g
body weight), a higher rate of fecal bile acid excretion (13.6 vs. 8.5
micromol/d/100 g body weight), a more efficient level of intestinal cholesterol
absorption (41.1% vs. 25. 3%), and a lower rate of hepatic sterol synthesis (338
vs. 847 nmol/h/g). Similar results were found in C57BL/6 and 129Sv inbred mice.
In matching groups of CD-1 mice fed a diet containing 1% cholesterol for 21 days,
hepatic cholesterol levels increased much more in the females (from 2.4 to 9.1
mg/g) than in the males (from 2. 1 to 5.2 mg/g). This occurred even though the
level of stimulation of cholesterol 7-hydroxylase activity in the females (79%)
exceeded that in the males (55%), as did the magnitude of the increase in fecal
bile acid excretion (females: 262% vs. males: 218%). However, in both sexes, bile
acid pool size expanded only modestly and by a comparable degree (females: 19%
vs. males: 26%) so that in the cholesterol-fed groups, the pool remained
substantially larger in the females than in the males (102.3 vs. 67.6
micromol/100 g body weight). Together, these data demonstrate that while male and
female CD-1 mice do not differ qualitatively in the way cholesterol feeding
changes their bile acid metabolism, the inherently larger bile acid pool in the
female likely facilitates the delivery of significantly more dietary cholesterol
to the liver than is the case in males, thereby resulting in higher steady-state
hepatic cholesterol levels.
PMID- 9755248
TI - Alpha3beta1-integrin as a critical mediator of the hepatic differentiation
response to the extracellular matrix.
AB - The extracellular matrix (ECM) promotes the differentiation of many cell types,
and ECM remodeling in the liver has been implicated in embryonic development,
tissue injury, and oncogenesis. Integrins are heterodimeric ECM receptors that
play critical roles in transducing the composition of the ECM in the cell
environment. We previously showed that mouse H2.35 cells, a conditionally
transformed, liver-derived cell line, assume a more differentiated hepatocyte
morphology and enhanced liver-specific gene expression when the cells are
cultured on gelatinous ECM substrata. Here we show that H2. 35 cells express
relatively high levels of alpha3beta1-integrins, similar to that previously shown
for immature hepatocytes, transformed hepatocytes, and biliary cells. However,
the cell morphological responses that depend on alpha3beta1-integrin have not
been defined. We found that transfecting H2.35 cells with antisense RNA construct
directed to alpha3-subunit messenger RNA perturbs the initial cell attachment to
laminin and collagen, and strongly inhibits cell morphological, proliferative,
and gene expression responses to a collagen gel substratum. In situ hybridization
to mouse embryo tissues demonstrates the presence of alpha3-subunit messenger
RNAs in newly formed hepatocytes. We suggest that alpha3beta1-integrins are
important for immature and transformed hepatocytes to respond morphologically to
the extracellular matrix.
PMID- 9755249
TI - Hepatic iron overload in patients with chronic viral hepatitis: role of HFE gene
mutations.
AB - Mild to moderate hepatic iron overload is frequent in patients with chronic viral
hepatitis (CH). We evaluated the role of hemochromatosis (HFE) gene mutations and
other acquired factors in the development of iron overload in these patients. We
studied 110 patients with chronic B or C viral hepatitis (31 women, 79 men),
including 20 with cirrhosis, and 139 controls. Hepatic iron was evaluated by
semiquantitative analysis in all the patients, and hepatic iron concentration
(HIC) was determined in 97 of them (26 women, 71 men). C282Y and H63D mutations
were sought in all the subjects by a polymerase chain reaction-restriction assay.
The frequency of HFE genotypes and alleles did not differ in patients and
controls. No relation was detected between hepatic iron stores and HFE gene
mutations in women. In men, all C282Y heterozygotes had iron overload, and the
H63D mutation was significantly more frequent in patients with more marked
hepatic siderosis than in those with mild or no siderosis (P = .0039) and in
controls (P = .0008). Heavy alcohol intake and hepatic cirrhosis were also
associated with increased hepatic iron stores in the men. In the 71 men in whom
HIC was measured, multiple regression analysis showed that this variable was
related independently only to alcohol intake and HFE gene mutations. We suggest
that in patients with CH, iron accumulates in the liver as the result of an
interplay between genetic and acquired factors, and that increased liver iron
stores may influence progression toward liver fibrosis.
PMID- 9755250
TI - Effect of interferon therapy on hepatitis C virus RNA in whole blood, plasma, and
peripheral blood mononuclear cells.
AB - Fifty-two patients with chronic hepatitis C virus (HCV) infection were treated
with standard doses of interferon alfa-2b. During treatment, HCV RNA detection
was studied in samples of whole blood (WB), plasma (Pl), and peripheral blood
mononuclear cells (PBMCs). Individuals were classified as sustained responders
(SRs), complete responders with relapse (CRs), partial responders (PRs), or
nonresponders (NRs) according to normalization of serum alanine transaminase
(ALT) during treatment and follow-up. Before treatment, 100% of WB samples and
more than 95% of Pl and PBMC samples were positive for HCV RNA. During treatment,
there was progressive clearance of HCV RNA from Pl and PBMCs in SRs and CRs, but
CRs had significantly more positive WB samples during and following treatment (P
<.0001). At 6 months, only 10% of CR patients were positive by Pl assay, but 50%
were positive by WB assay (P <.01). In the PR group, all WB samples remained
positive throughout treatment, although 25% to 40% of PBMC and Pl samples became
negative for HCV RNA during the first 2 months of therapy (WB > Pl or PBMC; P <
.001). However, at later times during treatment most Pl and PBMC samples in the
PR group were positive. Samples from the NR group showed no clearance of HCV RNA
from WB, Pl, or PBMC fractions. These data document the increased sensitivity of
WB assays for detecting HCV RNA in the peripheral blood of patients during
interferon therapy. Furthermore, our findings suggest that WB analysis of HCV RNA
may be a useful parameter to monitor in determining the end point of interferon
therapy.
PMID- 9755251
TI - High titers of antibodies inhibiting the binding of envelope to human cells
correlate with natural resolution of chronic hepatitis C.
AB - Most cases of hepatitis C virus (HCV) infection result in chronic disease;
however, a very small fraction of patients naturally clear the virus and resolve
chronic hepatitis. In an attempt to correlate immune response with chronic
disease resolution, we compared the antibody response in patients with different
outcomes of the infection. Antibody responses to HCV structural proteins were
assessed in 34 patients originally diagnosed with acute hepatitis. Five cases
resolved acute infection, 22 developed chronic hepatitis, and 7 naturally
resolved chronic hepatitis C. To estimate HCV neutralizing antibodies we used the
neutralization of binding (NOB) assay, which evaluates inhibition of the envelope
2 protein binding to human cells. Enzyme-linked immunosorbent assay was used for
the quantitative assessment of serum antibodies. The presence of HCV RNA was
ascertained by reverse transcription-polymerase chain reaction. In 6 of 7
patients naturally recovered from chronic hepatitis C, the emergence and the
persistence (for more than 3 months) of high serum titers (>1/600) of NOB
antibodies coincided with virus clearance and clinical resolution of hepatitis.
NOB antibody activity was observed in only 2 of 5 patients recovered from acute
hepatitis C. Chronic patients who did not show any resolution during the course
of the study developed low or no NOB antibodies. Because of the correlation
between prolonged high NOB titers and natural resolution of chronic hepatitis C,
vaccination or passive immunization aimed at high titers of NOB antibodies may be
valuable new therapeutic approaches for chronic hepatitis C.
PMID- 9755252
TI - 10-Year follow-up after interferon-alpha therapy for chronic hepatitis C.
AB - Sustained responses to interferon-alpha occur in 10% to 25% of patients with
chronic hepatitis C, but the long-term outcome is not well defined. We evaluated
the long-term clinical, histological, and virological outcomes of 10 patients
with chronic hepatitis C who were treated between 1984 and 1987 with interferon
alpha-2b for 52 +/- 6 weeks (total doses of 492 +/- 116 MU). Before therapy, all
10 had hepatitis C virus (HCV) RNA, elevations of serum aminotransferases, and
chronic hepatitis with fibrosis on liver biopsy. Clinical follow up was 6 to 13
years, and liver biopsies were done 5 to 11 years after initiation of therapy.
HCV RNA was assayed by qualitative and quantitative reverse transcriptase
polymerase chain reaction assays. Among 5 patients who had a 6-month sustained
response after therapy, all remained HCV RNA negative, and at last follow-up, 4
had normal and 1 minimally elevated serum aminotransferase levels. Liver biopsy
specimens were nonreactive for HCV RNA, and all the patients showed improvements
in both inflammation and fibrosis and were either normal or had mild, nonspecific
inflammatory changes. Among 5 patients without a sustained response, all
continued to have HCV RNA in serum and persistent or intermittent
aminotransferase elevations. Liver biopsy specimens showed little or no change in
necrosis and inflammation; all except 1 patient had progression of fibrosis
scores or cirrhosis. All 5 patients had symptoms of chronic hepatitis, 1
underwent liver transplantation, and another had progressive hepatic
decompensation. In conclusion, patients with a 6-month posttreatment virological
response have a favorable long-term clinical and histological outcome.
PMID- 9755253
TI - Ultrastructural analysis of hepatitis B virus in HepG2-transfected cells with
special emphasis on subviral filament morphogenesis.
AB - The intracellular accumulation of empty hepatitis B virus (HBV) particles of
filamentous shape leads to a direct cytopathic effect in so-called ground-glass
hepatocytes. The aim of this study was to investigate how these filaments can be
structurally formed at the cellular level. By electron microscopy, we reexamined
the HBV-producer HepG2T-14 cells, which have been described as producing a
substantial amount of empty HBV filaments compared with the other forms of HBV
particles. Examination of ultrathin sections of HepG2T14 cells revealed the
presence of HBV virions and filaments at the periphery of extremely large
intracellular cisternae, probably related to a pre-Golgi compartment. Very long
filaments appeared to be formed by a tubular budding of a long portion of the
cisterna membrane. This phenomenon may be identical to that observed in the
hepatocytes of HBV chronic carriers, in which the inability of the infected cell
to export long HBV filamentous particles through the cellular secretion pathway
seems to be at the origin of a direct cytopathic effect.
PMID- 9755254
TI - Hepatitis B virus replication in human HepG2 cells mediated by hepatitis B virus
recombinant baculovirus.
AB - A novel transient mechanism for studying hepatitis B virus (HBV) gene expression
and replication using recombinant HBV baculovirus to deliver the HBV genome to
HepG2 cells was generated. In HBV baculovirus infected HepG2 cells, HBV
transcripts, and intracellular and secreted HBV antigens are produced;
replication occurs as evidenced by the presence of high levels of intracellular
replicative intermediates and protected HBV DNA in the medium. Density-gradient
analysis of extracellular HBV DNA indicated that the DNA was contained
predominantly in enveloped HBV virions. Covalently closed circular (CCC) DNA is
present indicating that, in this system, HBV core particles are capable of
delivering newly synthesized HBV genomes back into the nuclei of infected cells.
HBV gene expression is driven exclusively from endogenous promoters. Levels of
HBV gene expression and replication can be achieved in HBV baculovirus-infected
HepG2 cells which far exceed levels found in HepG2 2.2.15 cells. HBV baculovirus
infection of HepG2 cells lends itself readily to experimental manipulation as
follows: 1) HBV expression can be initiated any time relative to seeding of HepG2
cells; 2) levels of HBV replication can be regulated over a wide range simply by
changing the baculovirus multiplicity of infection; 3) HBV replication is readily
detectable by one day post infection with HBV baculovirus and persists at least
through day eleven post infection; and (4) the transient nature of the infection
can be extended and/or enhanced by superinfecting the cultures. We conclude that
infection of HepG2 cells by HBV recombinant baculovirus represents a simple to
use and highly flexible system for studying the effects of antivirals and/or
cytokines on HBV production and for understanding HBV replication and
pathogenesis at the molecular level.
PMID- 9755256
TI - Management of ectopic varices.
PMID- 9755257
TI - New perspectives on the pathogenesis of Cryptosporidium biliary disease.
PMID- 9755255
TI - Mutations in the interferon-sensitivity determining region of hepatitis C virus
and transcriptional activity of the nonstructural region 5A protein.
AB - Amino acid (aa) mutations in the interferon-sensitivity determining region (ISDR)
(aa position 237-276 of the nonstructural region 5A [NS5A] protein consisting of
447 amino acids) of hepatitis C virus (HCV) are related to increased interferon
sensitivity and low viral load, but its mechanism has not been clarified.
Recently, the NS5A protein has been reported to have a transcriptional activation
function, like other viral transactivator proteins known to repress interferon
induced gene expression, and the ISDR overlaps one of the acidic amino acid
regions, putative domains conferring this activity. In the present study, we
investigated the transcriptional activation function of the ISDR itself and the
effect of amino acid mutations in the ISDR on this activity. The full-length or
truncated NS5A cDNA with different ISDR sequences was cloned into a yeast or
mammalian expression vector to form a fusion protein consisting of the GAL4 DNA
binding domain (GAL4-DBD) and NS5A protein. Following transfection, the
transcriptional activities of these constructs were determined using beta
galactosidase (yeast) or chloramphenicol acetyltransferase (CAT) (mammalian cell)
reporter gene expression under the control of GAL4 binding sites. In yeast, both
the full-length sequence of NS5A-R (a clone with one aa mutation in the ISDR) and
NS5A-S (a derivative of NS5A-R with six aa mutations in the ISDR) had no
distinguishable transcriptional activity, whereas an amino-terminal deletion
construct of NS5A-R (aa position 228-447) lacking 227 aa, showed remarkable
activity with the relative value of 117.0 over that of the backbone vector. The
same deletion mutant of NS5A-S produced five times higher activity with the
relative value of 575.0, indicating that aa mutations in the ISDR profoundly
affect this transcriptional activity. In a hepatoma cell line, HuH-7, the
transcriptional activity was more prominent with a construct consisting of only
the ISDR and short flanking sequences (aa 228-284) than larger deletion
constructs of NS5A-R. Analysis using six different ISDR clones revealed that
different mutations enhanced this activity to various extent compared with the
wild-type ISDR. In particular, site-directed mutagenesis targeted to the aa
position 252 showed that this aa residue had profound influence on the activity.
These results suggest that the ISDR has a transcriptional activity, and it is
enhanced by aa mutations that are also related to decreased viral load and
increased interferon sensitivity. The possible association between
transcriptional activation and interferon sensitivity or viral replication should
be studied further.
PMID- 9755258
TI - Hepatocellular carcinoma.
PMID- 9755259
TI - A novel use of xylitol sugar in preventing acute otitis media.
AB - BACKGROUND: Xylitol, a commonly used sweetener, is effective in preventing dental
caries. As it inhibits the growth of pneumococci, we evaluated whether xylitol
could be effective in preventing acute otitis media (AOM). DESIGN: Altogether,
857 healthy children recruited from day care centers were randomized to one of
five treatment groups to receive control syrup (n = 165), xylitol syrup (n =
159), control chewing gum (n = 178), xylitol gum (n = 179), or xylitol lozenge (n
= 176). The daily dose of xylitol varied from 8.4 g (chewing gum) to 10 g
(syrup). The design was a 3-month randomized, controlled trial, blinded within
the chewing gum and syrup groups. The occurrence of AOM each time the child
showed any symptoms of respiratory infection was the main outcome. RESULTS:
Although at least one event of AOM was experienced by 68 (41%) of the 165
children who received control syrup, only 46 (29%) of the 159 children receiving
xylitol syrup were affected, for a 30% decrease (95% confidence interval [CI]:
4.6%-55.4%). Likewise, the occurrence of otitis decreased by 40% compared with
control subjects in the children who received xylitol chewing gum (CI: 10.0%
71.1%) and by 20% in the lozenge group (CI: -12.9%-51.4%). Thus, the occurrence
of AOM during the follow-up period was significantly lower in those who received
xylitol syrup or gum, and these children required antimicrobials less often than
did controls. Xylitol was well tolerated. CONCLUSIONS: Xylitol sugar, when given
in a syrup or chewing gum, was effective in preventing AOM and decreasing the
need for antimicrobials.
PMID- 9755260
TI - Selective head cooling in newborn infants after perinatal asphyxia: a safety
study.
AB - AIMS: To determine the practicality and safety of head cooling with mild or
minimal systemic hypothermia in term neonates with moderate to severe hypoxic
ischemic encephalopathy. METHODS: Study group infants >/=37 weeks' gestation, who
had an umbilical artery pH =7. 09 or Apgars =6 at 5 minutes, plus evidence of
encephalopathy. Infants with major congenital abnormalities were excluded. TRAIL
DESIGN: Infants were randomized to either no cooling (controls; rectal
temperature = 37.0 +/- 0.2 degreesC, n = 10) or sequentially, either minimal
systemic cooling (rectal temperature = 36.3 +/- 0.2 degreesC, n = 6) or mild
systemic cooling (rectal temperature = 35.7 +/- 0.2 degreesC, n = 6). Head
cooling was accomplished by circulating water at 10 degreesC through a coil of
tubing wrapped around the head for up to 72 hours. All infants were warmed by
servo-controlled overhead heaters to maintain the allocated rectal temperature.
The rectal, fontanelle, and nasopharyngeal temperatures were continuously
monitored. RESULTS: From January 1996 to October 1997, 22 term infants were
randomized from 2 to 5 hours after birth. All infants showed a metabolic acidosis
at delivery, with similar umbilical artery pH in the control group (mean +/-
standard deviation, 6.79 +/- 0.25), minimal cooling group (6.98 +/- 0.21), and
mild cooling group (6.93 +/- 0.11), and depressed Apgar scores at 5 minutes in
the control group (4.5 +/- 2), minimal cooling group, (4.7 +/- 2) and mild
cooling group (6.0 +/- 1). In the mild-cooled infants, the nasopharyngeal
temperature was 34.5 degreesC during cooling, 1.2 degreesC lower than the rectal
temperature. This gradient narrowed to 0.5 degreesC after cooling was stopped. No
adverse effects because of cooling were observed. No infants developed cardiac
arrhythmias, hypotension, or bradycardia during cooling. Thrombocytopenia
occurred in 2 out of 10 controls, 2 out of 6 minimal cooling infants, and 1 out
of 6 mild cooling infants. Hypoglycemia (glucose <2.6 mM) was seen on at least
one occasion in 2 out of 10 controls, 4 out of 6 minimal cooling infants, and 1
out of 6 mild cooling infants. Acute renal failure occurred in all infants. The
metabolic acidosis present in all infants at the time of enrollment into the
study progressively resolved despite cooling, even in the mild hypothermia group.
CONCLUSIONS: Mild selective head cooling combined with mild systemic hypothermia
in term newborn infants after perinatal asphyxia is a safe and convenient method
of quickly reducing cerebral temperature with an increased gradient between the
surface of the scalp and core temperature. The safety of mild hypothermia with
selective head cooling is in contrast with the historical evidence of adverse
effects with greater depths of whole-body hypothermia. This safety study and the
strong experimental evidence for improved cerebral outcome justify a multicenter
trial of selective head cooling for neonatal encephalopathy in term infants.
PMID- 9755261
TI - Declining severity adjusted mortality: evidence of improving neonatal intensive
care.
AB - OBJECTIVES: Declines in neonatal mortality have been attributed to neonatal
intensive care. An alternative to the "better care" hypothesis is the "better
babies" hypothesis; ie, very low birth weight infants are delivered less ill and
therefore have better survival. DESIGN: We ascertained outcomes of all live
births <1500 g in two prospective inception cohorts. We estimated mortality risk
from birth weight and illness severity on admission and measured therapeutic
intensity. We calculated logistic regression models to estimate the changing odds
of mortality between cohorts. PATIENTS AND SETTING: Two cohorts in the same two
hospitals, 5 years apart (1989-1990 and 1994-1995) (total n = 739). RESULTS:
Neonatal intensive care unit mortality declined from 17.1% to 9.5%, and total
mortality declined from 31.6% to 18.4%. Cohort 2 had lower risk (higher birth
weight, gestational age, and Apgar scores and lower admission illness severity
for newborns >/=750 g). Risk-adjusted mortality declined (odds ratio, 0.52;
confidence interval, 0.29-0. 96). One third of the decline was attributable to
"better babies" and two thirds to "better care." Use of surfactant, mechanical
ventilation, and pressors became more aggressive, but decreases in monitoring,
procedures, and transfusions resulted in little change in therapeutic intensity.
CONCLUSIONS: Mortality decreased nearly 50% for infants <1500 g in 5 years. One
third of this decline is attributable to improved condition on admission that
reflects improving obstetric and delivery room care. Two thirds of the decline is
attributable to more effective newborn intensive care, which was associated with
greater aggressiveness of respiratory and cardiovascular treatments. Attribution
of improved birth weight specific mortality solely to neonatal intensive care may
underestimate the contribution of high-risk obstetric care in providing "better
babies."
PMID- 9755262
TI - Prospective study of persistence and excretion of human herpesvirus-6 in patients
with exanthem subitum and their parents.
AB - OBJECTIVE: To elucidate persistence of human herpesvirus-6 (HHV-6) in the blood
and excretion of the virus into several body fluids of patients with exanthem
subitum (ES), and to examine serologic and virologic findings of the parents
caring for the patients in the family setting. MATERIALS AND METHODS: During a 15
month period, 20 infants from 20 families (11 boys and 9 girls; mean age, 7.7
months; range, 4-11 months) with primary HHV-6 infection and a typical clinical
course of ES, and 15 parents from the 20 families (2 males and 13 females; mean
age, 28.2 years; range, 21-34 years) were enrolled in the study and examined
clinically and virologically. Primary infection with HHV-6 was confirmed by
isolation of the virus from peripheral blood mononuclear cells (MNCs), and
seroconversion or a significant increase in the antibody titers to HHV-6 by a
neutralization test. Viral persistence or excretion was examined by amplifying
the viral deoxyribonucleic acid (DNA) in serially collected peripheral blood
MNCs, plasma, saliva, stool, and urine samples with a nested polymerase chain
reaction method. Data on saliva from the parents were compared with those of 21
age-matched controls. RESULTS: Twenty infants with virologically confirmed ES had
HHV-6 DNA in MNCs persistently during and after the disease but in plasma only in
the first 5 days of ES. The viral DNA was also detected persistently or
intermittently in saliva and stool during and after the disease but rarely in
urine. On the other hand, the 15 parents examined of the 20 infants had no HHV-6
viremia nor viral DNA in peripheral blood MNCs and plasma except 1, but half of
them excreted viral DNA in saliva during and after ES. The frequency of excretion
of viral DNA into saliva was not significantly different from that of 21 control
parents. Only 1 of the 15 showed a fourfold increase in antibody titers to HHV-6
after possible exposure from their children. CONCLUSIONS: After systemic
replication of HHV-6 in the blood of patients with ES during the first 5 days of
the disease, the virus is excreted into saliva and stool persistently or
intermittently but rarely into urine. The presence of HHV-6 DNA in plasma
suggested active infection with the virus. Excretion of the virus into the saliva
of infants with ES and their parents suggests the source and transmission route
of infection with HHV-6.
PMID- 9755263
TI - Lyme arthritis in children: clinical epidemiology and long-term outcomes.
AB - OBJECTIVE: Although Lyme disease has become a relatively common cause of
arthritis among children in areas of the country in which the disease is endemic,
little information is available about the clinical epidemiology and long-term
outcomes of children with Lyme arthritis. We conducted a long-term follow-up
study to determine the clinical epidemiology of Lyme arthritis in children as
well as their long-term outcomes. PATIENTS AND METHODS: All children seen between
1982 and 1991 at the Pediatric Rheumatology Clinic at Newington Children's
Hospital (Newington, CT) with an initial diagnosis of Lyme disease were
identified. Medical records were reviewed and structured telephone interviews
were conducted to obtain demographic, clinical, and follow-up data. RESULTS: A
total of 90 children (63% boys) with a mean age of 8.3 years (range, 1.8-16
years) at the time of diagnosis of Lyme arthritis were evaluated. Lyme arthritis
was preceded by early Lyme disease in 23 (26%) of the children; however, only 8
(35%) of these children had been treated with appropriate antimicrobial therapy
at that early stage. Ninety percent of the children had arthritis of at least one
knee, while small joints were rarely involved. For the 31 children who underwent
arthrocentesis, the mean white blood cell count in the synovial fluid was 38 000
cells/mm3 (range, 7000-99 000 cells/mm3) with predominantly neutrophils. For the
79 children for whom an erythrocyte sedimentation rate was determined, the
highest level for 61 (77%) was >20 mm/h and for 36 (46%) was >50 mm/h.
Antimicrobial therapy was initiated 2 days to 5.5 years (median, 2 months) after
the onset of symptoms. However, 5 of the children were never treated with
antimicrobials. Fifty-one percent of the patients had a single episode of
arthritis, while 49% reported recurrent episodes of arthritis over a period of 1
week to 8 years (median, 6 months). Two children (2%) developed chronic arthritis
and underwent arthroscopic synovectomy. At the time of the telephone follow-up
evaluation, performed 2 to 12 years (median, 7 years) after the onset of the Lyme
arthritis, 4 children had ongoing musculoskeletal complaints that resulted in
mild to moderate impairment of school or sports activities, but none of the
children had evidence of active arthritis. CONCLUSION: The results of this
investigation suggest that the prognosis for children with Lyme arthritis who are
treated with appropriate antimicrobial therapy is excellent.
PMID- 9755264
TI - The effect of investigator compliance (observer bias) on calculated efficacy in a
pertussis vaccine trial.
AB - BACKGROUND: In the course of a large pertussis vaccine efficacy trial we realized
that investigator compliance could have a major impact on calculated vaccine
efficacy. DESIGN: In our pertussis vaccine efficacy trial, the study
investigators were to monitor illness in study families by telephone every 2
weeks. If a cough illness of >/=7 days duration was noted, the study child was to
be evaluated. If the cough illness persisted for >/=14 days, the child was to be
referred to a central investigator. For this report we analyzed study physician
evaluation rates and rates of referral to the central investigators. Physician
practices were separated into three compliance categories: high, intermediate,
and low. We analyzed vaccine efficacy of an acellular pertussis component DTP
vaccine (DTaP) and a whole cell pertussis component DTP vaccine (DTP) by
compliance category. Bordetella pertussis infection was documented by culture of
the organism in the study child or in a household contact or by a significant
antibody response to pertussis toxin determined by enzyme-linked immunosorbent
assay. RESULTS: Using a clinical case definition that included both mild and
typical pertussis (cough illness >/=7 days duration) efficacy of DTaP vaccine was
40% (95% confidence interval [CI] = -3-65) in the high compliance category and
78% (95% CI = 65-86) and 75% (95% CI = 53-87) in the intermediate and low
compliance groups, respectively. Similar, but less marked, differences in
efficacy were noted with DTP vaccine recipients. Using a clinical case definition
that required >/=21 days of cough with paroxysms, whoop, or vomiting (typical
pertussis) the efficacy of DTaP vaccine was 69% (95% CI = 41-83) in the high
compliance category and 86% (95% CI = 76-92) and 84% (95% CI = 64-93) in the
intermediate and low compliance groups, respectively. In contrast, the efficacy
of DTP vaccine did not vary by compliance category using this case definition.
The attack rate in children vaccinated with diphtheria and tetanus toxoids
vaccine (DT) was twofold less in low compliance physician practices when compared
with the rates in high and intermediate groups. The DT/DTaP and DT/DTP fold
change differences were less in the high compliance group compared with the
intermediate and low compliance groups. CONCLUSIONS: Our data suggest that
observer compliance (observer bias), can significantly inflate calculated vaccine
efficacy. It is likely that all recently completed efficacy trials have been
effected by this type of observer bias and all vaccines have considerably less
efficacy against mild disease than published data suggest.
PMID- 9755265
TI - Dietary sources of nutrients among US children, 1989-1991.
AB - OBJECTIVE: To identify major food sources of nutrients and dietary constituents
for US children. METHODS: Twenty-four-hour dietary recalls were collected from a
nationally representative sample of children age 2 to 18 years (n = 4008) from
the US Department of Agriculture's 1989-1991 Continuing Survey of Food Intakes by
Individuals. For each of 16 dietary constituents, the contribution of each of 113
food groups was obtained by summing the amount provided by the food group for all
individuals and dividing by total intake from all food groups for all
individuals. RESULTS: Milk, yeast bread, cakes/cookies/quick breads/donuts, beef,
and cheese are among the top 10 sources of energy, fat, and protein. Many of the
top 10 sources of carbohydrate (yeast bread, soft drinks/sodas, milk, ready-to
eat cereal, cakes/cookies/quick breads/donuts, sugars/syrups/jams, fruit drinks,
pasta, white potatoes); protein (poultry, ready-to-eat cereal, pasta); and fat
(potato chips/corn chips/popcorn) also contributed >2% each to energy intakes.
Ready-to-eat cereal is among the top contributors to folate, vitamin A, vitamin
C, iron, and zinc intakes. Fruit drinks, containing little juice, contribute
approximately 14% of total vitamin C intakes. CONCLUSIONS: Fortified foods are
influential contributors to many vitamins and minerals. Low nutrient-dense foods
are major contributors to energy, fats, and carbohydrate. This compromises
intakes of more nutritious foods and may impede compliance with current dietary
guidance.
PMID- 9755266
TI - Syncope recurrence in children: relation to tilt-test results.
AB - OBJECTIVES: To examine the intermediate-term outcome of children with syncope and
its relationship to tilt test. DESIGN: This was a retrospective study of 45
children. In 20, the tilt test was negative. Follow-up with respect to the
recurrence of syncope was obtained via chart review, a mailed questionnaire, or
telephone interview. RESULTS: Follow-up data were available on 15 children whose
tilt test was negative and on all 25 tilt-test positive children. Recurrent
syncope was significantly greater in the positive-tilt children (13 of 25) than
the negative-tilt children (2 of 15). There was no difference between the syncope
free group and the recurrent syncope group or between the tilt-positive and tilt
negative groups with respect to age at initial syncope, duration of symptoms, age
at tilt test, and duration of follow-up. Children with a positive tilt test and
those with recurrent syncope had more syncopal episodes before their evaluation
than either the group with a negative tilt test or the group with no recurrent
syncope, respectively. CONCLUSIONS: Syncope may recur after either a negative or
a positive tilt test. The recurrence rate, however, is higher for the tilt
positive children.
PMID- 9755267
TI - Early clinical markers for the development of bronchopulmonary dysplasia: soluble
E-Selectin and ICAM-1.
AB - OBJECTIVE: To test the hypothesis that in infants born at =29 weeks' gestation
soluble adhesion molecule concentrations would be higher in the first week of
life in infants that subsequently develop bronchopulmonary dysplasia than in
infants that do not. DESIGN AND METHODS: In cord blood and on days of life 1, 3,
and 7, we measured serum concentrations of soluble P-Selectin, E-Selectin, and
intercellular adhesion molecule-1 in samples obtained from infants =29 weeks'
gestational age. At 1 month of age we assessed the infants' clinical courses to
determine whether the infants met the criteria for the diagnosis of
bronchopulmonary dysplasia (BPD) and evaluated the infants' radiographic studies
to stage the level of BPD. On discharge, the duration of oxygen therapy, the
requirement for home oxygen therapy, and length of hospital stay were determined.
RESULTS: Concentrations of soluble P-Selectin were greatest in cord blood samples
obtained from all infants and were markedly reduced on day of life 1, regardless
of the subsequent development of BPD. In serum samples obtained from cord blood
and on days of life 1 and 3, soluble E-Selectin levels were higher in infants
that developed BPD than in infants that did not develop BPD. In addition, the
highest concentrations of soluble E-Selectin in serum samples from cord blood and
on day of life 1 were associated with the development of stage 3 or 4 BPD.
Soluble intercellular adhesion molecule-1 concentrations were higher on days of
life 3 and 7 in the infants that went on to develop BPD than in those that did
not. CONCLUSIONS: Because neutrophil attachment to endothelial cell adhesion
molecules is a key event in the initiation of an inflammatory response, the
association of higher early concentrations of soluble E-Selectin with the
development of BPD suggests that E-Selectin may play a key role in the
pathogenesis of lung inflammation and the development of BPD. This association
also suggests that inflammatory events or effects leading to inflammatory
responses occurring in the prenatal and/or very early perinatal periods
contribute significantly to the pathogenesis of BPD.
PMID- 9755268
TI - Clinically significant upper gastrointestinal bleeding acquired in a pediatric
intensive care unit: a prospective study.
AB - OBJECTIVES: To determine the incidence, risk factors, and complications
associated with or attributable to clinically significant upper gastrointestinal
(GI) bleeding acquired in a pediatric intensive care unit (ICU). METHODS:
Prospective, descriptive epidemiologic study in a multidisciplinary pediatric ICU
of a tertiary-care university hospital. Upper GI bleeding was considered to be
present if hematemesis occurred or blood was present in the gastric tube. An
upper GI bleed was qualified as clinically significant if two or three reviewers
independently assessed that at least one of the six complications considered for
analysis was attributable to the upper GI bleed. RESULTS: A cohort of 1114
consecutive admissions was enrolled; 108 (9.7%) were excluded mostly (37.0%)
because they already had an upper GI bleed at entry to the pediatric ICU. The
final sample included 1006 admissions (881 patients); 103 upper GI bleeds (10.2%)
were diagnosed, including 16 clinically significant upper GI bleeds (1. 6%).
Complications attributed to an upper GI bleed included: decreased hemoglobin
concentration (10 cases), transfusion (10), hypotension (3), and surgery (1).
Three independent risk factors for clinically significant upper GI bleeding were
retained by multivariate analysis: respiratory failure, coagulopathy, and
pediatric risk of mortality score >/=10. Nine of the 16 cases (56. 3%) with
clinically significant upper GI bleeding had three risk factors, 14 (87.5%) had
two, and 1 (6.3%) had none. CONCLUSIONS: Clinically significant upper GI bleeds
are rare in critically ill children. Prophylaxis to prevent them may be limited
to patients who present with at least two risk factors.
PMID- 9755269
TI - Evaluation of vaginal infections in adolescent women: can it be done without a
speculum?
AB - OBJECTIVE: Given that highly sensitive urine-based nucleic acid amplification
tests may eliminate the need for speculum exam to diagnose gonorrhea and
chlamydia cervicitis, we sought to determine if vaginal infections could be
diagnosed without using a speculum. METHODS: Matched pairs of vaginal specimens
were collected from participants before and during speculum exam for diagnosis of
trichomoniasis, bacterial vaginosis, and vulvovaginal candidiasis. Females age 12
to 22 years presenting to the Johns Hopkins adolescent primary care clinics who
required a pelvic examination were eligible to participate. A convenience sample
of 686 patients was recruited between July 1995 and August 1996. Paired vaginal
specimens were evaluated with blinded microscopic evaluation. Analysis consisted
of: 1) comparison of collection method sensitivities; and 2) assessment of
proportions of infections detected by one method that were also detected by the
other method. RESULTS: Sensitivities of speculum and nonspeculum collection
methods were 75% and 77% (difference = -2%; 95% confidence interval, -11%, 7%)
for trichomoniasis, 64% and 68% (difference = -4% [-10%, 3%]) for bacterial
vaginosis, and 85% and 80% (difference = 5% [-12%, 22%]) for vulvovaginal
candidiasis. The speculum method identified 88% (trichomoniasis), 90% (bacterial
vaginosis), and 81% (vulvovaginal candidiasis) of infections detected by the
nonspeculum method. The nonspeculum method identified 91% (trichomoniasis), 95%
(bacterial vaginosis), and 76% (vulvovaginal candidiasis) of infections detected
by the speculum method. CONCLUSIONS: Vaginal infections can be adequately
diagnosed without a speculum. Once urine-based diagnosis of gonorrhea and
chlamydia becomes well established, it may be possible to perform evaluations for
uncomplicated genitourinary complaints without using a speculum.
PMID- 9755270
TI - Prenatal cocaine exposure and child behavior.
AB - OBJECTIVE: The aim of this study was to evaluate previous teacher reports that
children exposed to cocaine prenatally have more problem behaviors. METHODS: A
historical, prospective design was used. Maternal subjects (n = 116) of 6-year
old singleton, term (>/=36 weeks) children, and the children's first-grade
teachers (n = 102) agreed to participate. The child's first-grade teacher,
blinded to study design and exposure status, rated the child's behavior with the
Conners' Teacher Rating Scales (CTRS) and an investigator-developed scale, the
Problem Behavior Scale (PROBS 14), measuring behaviors reported by educators to
be specific to cocaine exposure. Mothers were interviewed by telephone regarding
demographic and socioeconomic factors. RESULTS: Although the cocaine-exposed
group had higher (more problem behaviors) for each of the CTRS subscales, the
overall multivariate analysis of variance for the CTRS was not significant.
Children exposed to cocaine prenatally had higher scores (more problem behaviors)
for 11 of the 14 PROBS items and the overall multivariate analysis of variance
relating prenatal cocaine exposure to the PROBS was significant (Wilkes' lambda
=.775), even after controlling for gender and prenatal exposure to alcohol and
cigarettes. CONCLUSIONS: This pilot study supports that teachers blinded to
exposure status of early elementary students did rate the cocaine-exposed group
as demonstrating significantly more problem behaviors than control children.
Although an important first step, postnatal factors that also may influence
behavior were not evaluated; hence, causation is not addressed.
PMID- 9755271
TI - Catch-up growth in children treated with home enteral nutrition.
AB - OBJECTIVE: This study was designed to determine the effect of home enteral
nutrition on the outcomes of growth and the relationship between growth and
entrance anthropometric criteria. METHODS: We reviewed the medical records of 78
consecutive children (median age, 20 months) who were enrolled in the home
enteral feeding program at the Alberta Children's Hospital (Calgary, Alberta,
Canada) between 1993 and 1995. Weights, heights, and weight-for-heights were
expressed as Z scores, using the Centers for Disease Control and Prevention
anthropometric growth curve software. To evaluate growth outcome, the total group
was further subdivided using anthropometric criteria into appropriate, wasted, or
stunted at the time of entry to the program. In a subgroup of 36 children on whom
anthropometric data was available for a median length of 5.7 months, Z scores
were compared at 3 points in time: before entry, at time of entry, and last
follow-up. RESULTS: Patients were classified into five main groups: 11 (14%) had
pulmonary disease, 26 (33%) had a gastrointestinal disorder, 21 (27%) had
congenital defects, 10 (13%) had a neurologic disorder, and the remaining 10
(13%) had a variety of other illnesses, including malignancies and metabolic
disorders. Patients were on the program for a median duration of 8.9 months. It
was found that during the period of support within the program, enteral feeding
was successful in improving weight-for-age Z scores by 0.42 standard deviations
but the effect on height-for-age Z scores and weight-for-height Z scores did not
reach significance for this population. The subgroup of 36 children on whom
longitudinal anthropometric data was available before entering the program was
found to have had a significant drop in weight Z scores between the time before
program entry (median length of time, 5.7 months) and the time of program entry,
which indicates that these children were falling off the growth curve before
commencing enteral feeding. To evaluate growth outcome, the total group was
further subdivided using anthropometric criteria into appropriate, wasted, or
stunted at the time of entry to the program. In the group of appropriate growth
patients, while in the program, 50% had catch-up growth for weight (positive
change in Z scores) and 33% for height. In the wasted patients, 92% improved
their weight percentile and 75% their height percentile. In the stunted group,
71% had catch-up growth for weight and 74% for height. CONCLUSION: We concluded
that the enteral feeding program was able to promote catch-up growth or maintain
growth along percentiles in the majority of children.
PMID- 9755274
TI - Bisphosphonates for treatment of childhood hypercalcemia.
AB - Most clinicians only have a limited experience in treating childhood
hypercalcemia with bisphosphonates. We report our experience in the use of
intravenous and oral bisphosphonates in a 5-year-old with hypercalcemia secondary
to acute lymphocytic leukemia, a 16-year-old with immobilization hypercalcemia,
and a 14-year-old with chronic hypercalcemia of unknown cause. Single infusions
of 0.5 mg/kg and 1 mg/kg of intravenous pamidronate were administered over 4
hours. No adverse reactions were observed except for hypocalcemia. A dose between
10 and 20 mg of oral alendronate was successfully used to maintain normocalcemia
in the patient with chronic hypercalcemia. In our experience, the administration
of bisphosphonates has enabled us to achieve normocalcemia in all cases, and in
all cases there were no significant side effects. Long-term potential side
effects from their use in children during the active phase of growth remain
unknown.
PMID- 9755273
TI - Pertussis encephalopathy with high cerebrospinal fluid antibody titers to
pertussis toxin and filamentous hemagglutinin.
AB - A 7-year-old unimmunized girl with pertussis presented with respiratory failure
and electroencephalographic evidence of an encephalopathy. The cerebrospinal
fluid (CSF)/serum ratio of antibodies to pertussis toxin and filamentous
hemagglutinin were 11- and ninefold higher than the CSF/serum ratio of total
immunoglobulin G. The CSF/serum ratio of albumin was normal. These findings
indicate production of antibodies in the central nervous system to Bordetella
pertussis antigens and imply, therefore, that the pertussis encephalopathy in
this girl was associated with the entry of pertussis antigens into the central
nervous system.
PMID- 9755272
TI - Comparison of fentanyl/midazolam with ketamine/midazolam for pediatric orthopedic
emergencies.
AB - OBJECTIVE: Emergency management of pediatric fractures and dislocations requires
effective analgesia, yet children's pain is often undertreated. We compared the
safety and efficacy of fentanyl- versus ketamine- based protocols. METHODOLOGY:
Patients 5 to 15 years of age needing emergency fracture or joint reduction (FR)
were randomized to receive intravenous midazolam plus either fentanyl (F/M) or
ketamine (K/M). Measures of efficacy were observational distress scores and self-
and parental-report. Measures of safety were frequency of abnormalities in and
need for support of cardiopulmonary function and other adverse effects. RESULTS:
During FR, K/M subjects (n = 130) had lower distress scores and parental ratings
of pain and anxiety than did F/M subjects (n = 130). Although both regimens
equally facilitated reductions, deep sedation, and procedural amnesia,
orthopedists favored K/M. Recovery was 14 minutes longer for K/M. Fewer K/M
subjects had hypoxia (6% vs 25%), needed breathing cues (1% vs 12%), or required
oxygen (10% vs 20%) than did F/M subjects. Two K/M subjects required assisted
ventilation briefly. More K/M subjects vomited. Adverse emergence reactions were
rare but equivalent between regimens. CONCLUSIONS: During emergency pediatric
orthopedic procedures, K/M is more effective than F/M for pain and anxiety
relief. Respiratory complications occurred less frequently with K/M, but
respiratory support may be needed with either regimen. Both regimens facilitate
reduction, produce amnesia, and rarely cause emergence delirium. Vomiting is more
frequent and recovery more prolonged with K/M.
PMID- 9755275
TI - Principles of child health care financing. American Academy of Pediatrics.
Committee on Child Health Financing.
AB - Child health care financing must maximize access to and ensure quality
comprehensive child and maternal care. This policy statement replaces the 1993
policy statement, "Principles of Child Health Care Financing." Changes reflect
new state and federal legislation that affect child health care financing. The
principles outlined in the policy statement will be used to evaluate the changing
structure of health care financing.
PMID- 9755276
TI - Issues in the application of the resource-based relative value scale system to
pediatrics: a subject review. American Academy of Pediatrics. Resource-Based
Relative Value Scale Project Advisory Committee.
AB - In today's rapidly changing health care environment, it is crucial to understand
the genesis and concepts of the Medicare Resource-based Relative Value Scale
(RBRVS) physician fee schedule. Many third-party payers, including state Medicaid
programs, Blue Cross-Blue Shield agencies, and managed care organizations are
using variations of the Medicare RBRVS to determine physician reimbursement and
capitation rates. Because the RBRVS fee schedule was originally created for
Medicare only, pediatric-specific Current Procedural Terminology codes and
pediatric practice expense issues were not included. The American Academy of
Pediatrics agrees with the use of the Current Procedural Terminology codes and
the RBRVS physician fee schedule and continues to work to rectify the inequities
of the RBRVS system as they pertain to pediatrics.
PMID- 9755277
TI - Detection of Mycobacterium tuberculosis in gastric aspirates collected from
children: hospitalization is not necessary.
AB - OBJECTIVE: To compare the yields of gastric aspirates collected for culture of
Mycobacterium tuberculosis from children evaluated as outpatients versus
inpatients and to determine factors associated with a positive culture. METHODS:
Retrospective study of 100 children <12 years of age with tuberculosis diagnosed
at a pediatric referral hospital or in one of two tuberculosis control programs
in California. RESULTS: Of the 100 children who had tuberculosis, 80 had at least
one gastric aspirate collected. M tuberculosis was isolated from 33 (41%) of the
80 children who had a gastric aspirate; 4 children had a positive culture from an
aspirate subsequent to the first. Inpatients had a higher proportion of positive
gastric aspirates than that of children who had aspirates collected as
outpatients (48% vs 37%); however, this difference was not statistically
significant. Resistance to isoniazid was found in three isolates (9%) of children
all of whose presumptive source case had a susceptible strain of M tuberculosis.
Characteristics that were associated with an approximately 50% yield from gastric
aspirates were identification of a source case, age <2 years, birth in the United
States, symptomatic tuberculosis, and pulmonary disease. CONCLUSIONS: The culture
of M tuberculosis from gastric aspirates of children in the outpatient setting
has a yield comparable to aspirates collected from hospitalized children.
Collection of gastric aspirates in the outpatient setting will reduce both the
cost and the inconvenience of the procedure. Although the yield from gastric
aspirates is relatively low, important information including drug susceptibility
patterns may be obtained. tuberculosis, gastric aspirate, children.
PMID- 9755278
TI - Serial serum C-reactive protein levels in the diagnosis of neonatal infection.
AB - OBJECTIVE: To evaluate serial serum C-reactive protein (CRP) levels for diagnosis
of neonatal infection. SETTING: A regional intensive care nursery and two
community intensive care nurseries. METHODS: All neonates treated for suspected
bacterial infection were prospectively evaluated using a standardized clinical
pathway. Infants were categorized as having proven sepsis (bacteria isolated from
blood, cerebrospinal fluid, or urine culture), probable sepsis (clinical and
laboratory findings consistent with bacterial infection without a positive
culture), or no sepsis (findings not consistent with sepsis), without
consideration of CRP levels. Infants whose blood cultures yielded skin flora but
who demonstrated no other signs of bacterial infection were not considered to
have sepsis. CRP levels were determined at the initial evaluation and on each of
the next two mornings. Sensitivity, specificity, predictive values, and
likelihood ratios were calculated for the first (CRP #1), second (CRP #2), higher
of the second and third (CRP #2 and #3), or highest of all three CRP levels (CRP
x 3). RESULTS: Sepsis was suspected within the first 3 days after birth in 1002
infants (early-onset) and on 184 occasions in 134 older infants (late-onset).
There were 20 early-onset and 53 late-onset episodes of proven sepsis, and 74
early-onset and 12 late-onset episodes of probable sepsis. CRP #1 had
sensitivities of 39.4% and 64.6% for proven or probable sepsis and 35.0% and
61.5% for proven sepsis in early-onset and late-onset episodes, respectively. CRP
levels on the morning after the initial evaluation (CRP #2) had higher
sensitivities (92. 9% and 85.0% for proven or probable sepsis and 78.9% and 84.4%
for proven sepsis in early-onset and late-onset episodes, respectively), and
normal results were associated with lower likelihoods of infection (likelihood
ratios for normal results of 0.10 and 0.19 for proven or probable sepsis and 0.27
and 0.21 for proven sepsis, in early-onset and late-onset episodes,
respectively). Three serial serum CRP levels had sensitivities of 97.8% and 98.1%
for proven or probable sepsis and 88.9% and 97.5% for proven sepsis in early
onset and late-onset episodes, respectively. The negative predictive values for
CRP x 3 were 99.7% and 98.7% for both proven or probable sepsis and for proven
sepsis in early-onset and late-onset episodes, respectively. A CRP level obtained
at the time of the initial evaluation can be omitted without significant loss of
sensitivity or negative predictive value: the sensitivities of CRP #2 and #3 were
97.6% and 94.4% for proven or probable sepsis and 88.9% and 96.4% for proven
sepsis in early-onset and late-onset episodes, respectively; negative predictive
values were 99.7% both for proven and for proven or probable early-onset sepsis,
97.6% for proven or probable late-onset infection, and 98.8% for proven late
onset infection. Serial normal CRP levels were associated with a markedly reduced
likelihood of infection as compared with that in the entire population before
testing, with likelihood ratios ranging from 0.03 to 0.16 for the various
subgroups. Maximum CRP levels >3 mg/dL had positive predictive values >20% for
proven or probable early-onset infections and for proven or probable and proven
late-onset infections, but only those >6 mg/dL had such a high positive
predictive value for proven early-onset sepsis. CONCLUSIONS: Serial CRP levels
are useful in the diagnostic evaluation of neonates with suspected infection. Two
CRP levels <1 mg/dL obtained 24 hours apart, 8 to 48 hours after presentation,
indicate that bacterial infection is unlikely. The sensitivity of a normal CRP at
the initial evaluation is not sufficient to justify withholding antibiotic
therapy. The positive predictive value of elevated CRP levels is low, especially
for culture-proven early-onset infections.
PMID- 9755279
TI - Limited evaluation of microscopic hematuria in pediatrics.
AB - OBJECTIVE: The purpose was to determine the value of the standard laboratory and
radiologic evaluation of microscopic hematuria in children, and to determine the
prevalence of idiopathic hypercalciuria in those children referred for evaluation
of unexplained microscopic hematuria. METHODS: This was a retrospective study of
325 children referred from 1985 to 1994 for the evaluation of asymptomatic
microscopic hematuria. The diagnostic studies reviewed included serum creatinine,
blood urea nitrogen, serum electrolyte studies, serum complement concentration,
antinuclear antibody, urinalysis, urine calcium to creatinine ratios, urinary
protein to creatinine ratio and/or 24-hour urinary protein excretion, renal
ultrasounds, intravenous pyelograms, voiding cystourethrograms, and historical
information. RESULTS: All creatinine and electrolyte values were normal for age,
and none of the biochemical tests obtained in the children with hypercalciuria
was abnormal. Of the 325 patients with idiopathic microscopic hematuria, only 18
had abnormal renal ultrasound examinations and 9 voiding cystourethrograms showed
low-grade reflux. Hypercalciuria was found in 29 patients. The family history was
positive for urolithiasis in 16% of patients without hypercalciuria compared with
14% of patients with hypercalciuria. A positive family history of hematuria was
reported in 25% of patients; 62 patients did not have hypercalciuria and 4 of the
patients had hypercalciuria. Microscopic hematuria in children is a benign
finding in the vast majority of children. CONCLUSIONS: Our data demonstrate that
a renal ultrasound, voiding cystourethrogram, cystoscopy, and renal biopsy are
not indicated in the work-up of microscopic hematuria, and microhematuria in the
otherwise healthy child is a minimal health threat, rarely indicative of serious
illness.
PMID- 9755280
TI - Cost-effective treatment of phimosis.
AB - OBJECTIVE: To determine the most cost-effective treatment for phimosis. DESIGN:
The costs of three treatment strategies for treating phimosis were evaluated
using a decision-tree analysis. Three therapeutic approaches were considered:
circumcision, preputial plasty (the use of plastic surgical techniques to enlarge
the preputial opening without removing tissue), and topical therapy with steroids
and nonsteroidal antiinflammatories. Published failure and complication rates
were used to calculate the cost per case. Outcome Measures. Cost in dollars to
treat each case of phimosis. RESULTS: Topical steroid therapy was the most cost
effective strategy, costing between $758 and $800 per case. Preputial plasty cost
between $2515 and $2580 per case. Circumcision cost between $3009 and $3241 per
case. CONCLUSIONS: The most cost-effective management for treating phimosis is to
initiate topical therapy. Daily external application from the tip of the foreskin
to the glandis corona with betamethasone 0.05% cream for 4 to 6 weeks has been
demonstrated to be very effective, resulting in a 75% savings compared with
circumcision. Surgical intervention should not be considered until topical
therapy has been given an adequate trial. When contemplating surgery, the lower
morbidity, lower costs, and tissue preservation of preputial plasty may make it
preferable.
PMID- 9755281
TI - Health care utilization by children with chronic illnesses: a comparison of
medicaid and employer-insured managed care.
AB - OBJECTIVES: This study compared utilization of health care services by children
with chronic conditions who were insured by either Medicaid or an employer group
in 1992 and 1993. Five chronic conditions were selected to illustrate patterns of
service use: asthma, attention deficit disorder, diabetes, epilepsy, and sickle
cell anemia. METHODOLOGY: Administrative databases were used to develop estimates
of health services utilization for children <18 years of age with the five
selected conditions, who had been enrolled for at least 6 continuous months. All
claims for a child identified with one of these five conditions were included in
the analysis, including claims for diagnoses and procedures not directly related
to the primary diagnosis. Estimates were derived for eight services (eg, hospital
admissions, emergency department (ED), home health). Data were used from two
Independent Practice Association model health plans in two states. Differences
across the states were controlled by selecting one Medicaid and one employer
insured program from each of the two plans in both states. Regional variation was
controlled for because both health plans were located in one geographical region.
In each case, physicians were paid on a fee-for-service basis, with generally
open access to specialists rather than primary care gatekeeper models of
delivery: t tests were used to compare service use rates between Medicaid and
employer-insured populations. RESULTS: A total of 8668 children across all health
plan groups had at least one of the selected conditions. Because Medicaid
enrolled-children tended to be younger, analyses were adjusted for age. In both
systems, a greater percentage of Medicaid children had these five study
conditions (5%) compared with employer-insured children (3%), suggesting that the
Medicaid population was sicker. Mean length of enrollment during the 2-year study
was longer for children in employer-insured programs. Children with chronic
conditions enrolled in Medicaid managed care generally used services at a higher
rate compared with children with similar conditions enrolled in employer-insured
managed care. The extent of the increased use varied by condition, by service
type, and by plan. Children with any of the chronic conditions studied had from 2
to almost 5 times more ED visits if they were enrolled in Medicaid than if they
were enrolled in employer-based managed care, depending on the specific
condition. In one of the two plans, Medicaid-enrolled children had more
outpatient services, laboratory services, and radiography services than their
counterparts in employer-based managed care. The same pattern of use was found
for home health services (except for children with diabetes) and for office
visits (except for children with sickle cell). The results show higher use of all
services by children with asthma and diabetes in Medicaid managed care compared
with employer-based managed care. In contrast, the pattern is mixed for children
with epilepsy and sickle cell. The sample size of children with these conditions
was smaller than with the three other conditions, which may account, in part, for
a varied pattern of results. The pattern of use for attention deficit
hyperactivity disorder (ADHD) was generally different from the other conditions.
Children with ADHD in employer-based managed care had more hospital admissions,
hospital days, and office visits than their counterparts in Medicaid managed
care. In contrast, Medicaid-enrolled children with ADHD had more ED visits,
laboratory services, outpatient hospital visits, and radiography services. Other
than ED visits, the differences in service use between Medicaid and employer
insured children with ADHD were minimal. Of note, the pattern for ADHD is the
same for most services for Plans A and B (excluding home health visits). This
utilization pattern may reflect service use for comorbid conditions. Part of this
difference may be explained by differences in Medicaid e
PMID- 9755282
TI - Risk factors for early childhood malnutrition in Uganda.
AB - OBJECTIVE: To assess the dietary and environmental factors influencing stunting
and other signs of poor nutritional status of children <30 months of age in a
central Ugandan community, whose main dietary staples are banana (matoki) and
maize. METHODS: The study was a cross-sectional survey using stratified
multistage random sampling to select households with a child <30 months of age in
rural and semi-urban environments. A questionnaire was administered to mothers of
261 infants and toddlers in their home setting. Their health status was assessed
by clinical examination and anthropometric measurements (mid-upper arm
circumference [MUAC], weight, and supine length). RESULTS: A large minority
(21.5%) of the children surveyed were found in poor health after clinical
examination: 3.8% being classified as suffering from kwashiorkor and 5.7% with
marasmus. A high proportion of children were stunted (23. 8%), underweight
(24.1%), or had low MUAC (21.6%). Although rural living, poor health, the use of
unprotected water supplies, lack of charcoal as fuel, lack of milk consumption,
and lack of personal hygiene were shown as risk factors for marasmus and
underweight, different factors were found to be associated with risk of stunting
and low MUAC, despite these three parameters being significantly correlated. For
stunting the risk factors were: age of the child, poor health, prolonged
breastfeeding (from >18 months to <24 months), low socioeconomic status of the
family, poor education of the mother of infants <12 months, lack of paraffin as
fuel, consumption of food of low energy density (<350 kcal/100 g dry matter),
presence of eye pathology, and consumption of small meals. Risk factors for low
MUAC were poor health, lack of meat and cow's milk consumption, low intake of
energy from fat, and less well educated and older mothers. Food taboos had no
influence on any of the anthropometric measurements. Although 93.1% of the
children had been immunized against tuberculosis, polio, diphtheria, and measles
and showed better general health than children who were not immunized, there was
a high prevalence of infection in the week preceding the survey interview,
including diarrhea (23.0%), malaria (32.3%), or cough/influenza (72.8%).
CONCLUSIONS: This first account of dietary and environmental risk factors
involved in the etiology of early childhood malnutrition in Uganda indicates
differences in risk factors for marasmus and underweight compared with stunting
and low MUAC. The high prevalence of malnutrition and current infection of
children in this survey suggests poor immune function as a result of inadequate
nutrition.
PMID- 9755283
TI - Sexual abuse of children: intersection with the HIV epidemic.
AB - OBJECTIVE: Sexual transmission of human immunodeficiency virus (HIV) is the
predominant risk exposure among adolescents and adults reported with HIV
infection and acquired immunodeficiency syndrome (AIDS). Although perinatal
transmission accounts for the majority of HIV infection in children, there have
been reports of HIV transmission through sexual abuse of children. We
characterized children <13 years of age who may have acquired HIV infection
through sexual abuse. METHODS: All reports by state and local health departments
to the national HIV/AIDS surveillance system of children with HIV infection not
AIDS (n = 1507) and AIDS (n = 7629) through December 1996 were reviewed for
history of sexual abuse. Information was ascertained from data recorded on the
case report form as well as investigations of children with no risk for HIV
infection reported or identified on initial investigation. For children with a
possible history of sexual abuse, additional data were collected, including how
sexual abuse was diagnosed; characteristics of the perpetrator(s) (ie, HIV status
and HIV risks); and other possible risk factors for the child's HIV infection.
RESULTS: Of 9136 children reported with HIV or AIDS, 26 were sexually abused with
confirmed (n = 17) or suspected (n = 9) exposure to HIV infection; mean age of
these children at diagnosis of HIV infection was 8.8 years (range, 3 to 12
years). There were 14 females and 3 males who had confirmed sexual exposure to an
adult male perpetrator at risk for or infected with HIV; of these, 14 had no
other risk for HIV infection, and 3 had multiple risks for HIV infection (ie,
through sexual abuse, perinatal exposure, and physical abuse through drug
injection). The other 9 children (8 females, 1 male) had no other risk factors
for HIV infection and were suspected to have been infected through sexual abuse,
but the identity, HIV risk, or HIV status of all the perpetrator(s) was not
known. All cases of sexual abuse had been reported to local children's protective
agencies. Sexual abuse was established on the basis of physician diagnosis or
physical examination (n = 20), child disclosure (n = 15), previous or concurrent
noncongenital sexually transmitted disease (n = 9), and for confirmed cases,
criminal prosecution of the HIV-infected or at-risk perpetrator (n = 8). For the
17 children with confirmed sexual exposure to HIV infection, 19 male perpetrators
were identified who were either known to be HIV infected (n = 18) or had risk
factors for HIV infection (n = 17), most of whom were a parent or relative.
CONCLUSIONS: These 26 cases highlight the tragic intersection of child sexual
abuse and the HIV epidemic. Although the number of reported cases of sexual
transmission of HIV infection among children is small, it is a minimum estimate
based on population-based surveillance and is an important and likely
underrecognized public health problem. Health care providers should consider
sexual abuse as a possible means of HIV transmission, particularly among children
whose mothers are HIV-antibody negative and also among older HIV-infected
children. The intersection of child abuse with the HIV epidemic highlights the
critical need for clinicians and public health professionals to be aware of the
risk for HIV transmission among children who have been sexually abused, and of
guidelines for HIV testing among sexually abused children, and to evaluate and
report such cases.
PMID- 9755284
TI - Parent reports on willingness to accept childhood immunizations during urgent
care visits.
AB - OBJECTIVES: To 1) describe whether parents would be willing to accept childhood
immunizations at urgent care visits; and 2) identify predictors of parents'
willingness to accept childhood immunizations at urgent care visits. DESIGN AND
PARTICIPANTS: Cross-sectional telephone survey of parents of children aged 18 to
24 months who were underimmunized according to a computerized immunization
tracking system and who had recently made an urgent care visit in a regional
group-model health maintenance organization in Northern California. Chart review
was conducted to confirm immunization status and to identify contraindications to
vaccination. RESULTS: Of the 424 eligible participants, 351 (83%) completed
interviews. Children with contraindications to vaccination and children who were
actually up-to-date at the time of the urgent care visit were excluded, leaving
263 families in the final analysis. Among these parents, 75% said they would have
been willing to have their child immunized at the urgent care visit in question
if the physician had suggested it. An additional 11% said they would have
accepted vaccination if the physician told them that the shot would be safe and
strongly encouraged them to accept it. Overall, 86% reported they theoretically
would have accepted an immunization during the urgent care visit. In the
multivariate analysis, the strongest predictors of stated willingness to accept
shots at the urgent care visit were the parent: 1) not being aware that their
child was underimmunized (odds ratio [OR] 3.5, 95% confidence interval [CI], 1.6
7.7); 2) perceiving that the child was not very sick at the visit (OR 1.8, 95%
CI, 1.1-3.0); 3) being less concerned about the risk of shots (OR 1.8, 95% CI,
1.2-2.5); and 4) being of nonwhite race (OR 3.6, 95% CI, 1.6-7.7). Income and
education were not significantly associated with reported willingness to accept
immunization. CONCLUSIONS: We conclude that most parents of underimmunized
toddlers report being willing to accept immunizations during urgent care visits
if the clinician recommends it. More effective ways of alerting providers in
urgent care settings when immunizations are due, such as indications on a chart
or registration form, hold promise for improving immunization coverage rates.
PMID- 9755285
TI - Computer-assisted diagnosis of pediatric rheumatic diseases.
AB - OBJECTIVE: AI/RHEUM is a multimedia expert system developed originally to assist
in the diagnosis of rheumatic diseases in adults. In the present study we
evaluated the usefulness of a modified version of this diagnostic decision
support system in diagnosing childhood rheumatic diseases. METHODOLOGY: AI/RHEUM
was modified by the addition of 5 new diseases to the knowledge base of the
system. Criteria tables for each of the diseases included in the knowledge base
were modified to suit the needs of children. The modified system was tested on 94
consecutive children seen in a pediatric rheumatology clinic. RESULTS: AI/RHEUM
made the correct diagnosis in 92% of the cases when the diagnosis was available
in the knowledge base of the system. It was also shown to be effective in the
education of pediatric trainees through its multimedia features. CONCLUSIONS:
AI/RHEUM is an expert system that may be helpful to the nonspecialist as a
diagnostic decision support system and as an educational tool.
PMID- 9755286
TI - Endogenous glutathione conjugates: occurrence and biological functions.
PMID- 9755287
TI - The B1 receptors for kinins.
PMID- 9755288
TI - Prediction of pharmacokinetic alterations caused by drug-drug interactions:
metabolic interaction in the liver.
PMID- 9755289
TI - Receptors for purines and pyrimidines.
PMID- 9755290
TI - Classification and biology of astrocytic gliomas.
AB - The presented classification of astrocytic gliomas follows the system adopted by
the WHO which was last published in 1993. The nosographic position of each tumour
type is discussed in relation to previous positions and the rationale of changes
is provided. The biology and pathology of anaplasia, leading from astrocytoma to
glioblastoma, are discussed briefly. The increasing genotypic and phenotypic
heterogeneity is described in its progressive stages. A series of genetic changes
are associated with the main histologic features of malignancy , such as TP53
mutations, EGFR amplification, CDKN2 deletion, etc. The genetic differences
between primary and secondary glioblastomas are emphasised. Tumour-associated
biological events are presented: cell invasion and spread, necrosis and apoptosis
and angiogenesis are all discussed in some detail. Of each event a short survey
on the principal phenotypic and molecular features is given with emphasis on
their significance to pathogenesis. Each tumour type is briefly summarised from
epidemiological, clinical and pathological standpoints.
PMID- 9755291
TI - New frontiers in therapy of malignant gliomas.
AB - The prognosis of patients with malignant gliomas remains dismal despite the
development of a multidisciplinary approach to their treatment. There is a strong
need for novel therapeutic approaches that can make a definite impact in the
clinical course of these tumours. Although there have been several advances in
diagnostic modalities, surgical techniques and cytotoxic therapies, the
development of newer therapies has been hampered by the limited understanding of
the factors that determine the biological nature of gliomas. However, inroads are
now being made into the understanding of the genetic make-up, biological
behaviour and therapeutic response of these tumours, which are expected to pave
the way for new modes of treatment. In this article, we review the advances made
in the identification of potential targets for glioma therapy and the recent
clinical trials utilising biological therapies and newer cytotoxic agents.
PMID- 9755292
TI - Trends in surgical management of astrocytomas and other brain gliomas.
AB - In recent years, surgical treatment of cerebral gliomas has made significant
technical advances (e.g. microsurgery and neuronavigation) and has also
benefitted from improvement in diagnostic techniques and biopathology. Thanks to
this progress, there has been a reduction in the surgical mortality and morbidity
of highly malignant neoplasms such as glioblastoma multiforme and
medulloblastoma, although there has not been any significant improvement in
survival. On the other hand, for a specific group of circumscribed and resectable
brain gliomas, modern neurosurgery is potentially curative in a high proportion
of cases, even if the gliomas are located in deep and previously inaccessible
brain regions. These "benign" variants of cerebral gliomas occur mainly in
children and young adults, i.e., in subjects with a long life-expectancy.
Astrocytoma, oligodendroglioma and ependymoma are a third group of cerebral
gliomas for which modern neurosurgery offers interesting new possibilities.
PMID- 9755293
TI - Modern aspects of radiation therapy for glial tumours of the brain.
AB - Radiation was conclusively proved to be of value in the treatment of malignant
gliomas in the late 1970's where it enabled an approximate doubling of the
survival time. Further study defined a number of prognostic factors which provide
a basis for selecting patients for treatment. The introduction of computer
tomography (and later magnetic resonance) scanning allowed a more rational
approach to target volume definition and a reduction in radiation-related
morbidity. Dose-ranging studies defined a standard approach to treatment (60 Gray
in 30 fractions). Since then numerous attempts have been made to improve on these
results. Marginal benefits have been claimed for altered fractionation schemes,
limited volume dose escalation (implants and stereotaxy), radiation sensitisers
and particle therapies. However none has become routine in clinical practice.
Advances in planning technology have allowed a further reduction in the volume of
normal brain irradiated and the potential for dose escalation. Low grade
astrocytoma has not been examined in the same way and great doubt exists with
respect to optimal treatment. There is a great opportunity for research to
realise the potential in the new techniques for improving the outlook for
patients with malignant glioma and in clarifying the role of radiation in low
grade tumours.
PMID- 9755294
TI - Heparin and nitric oxide treatment in experimental acute pancreatitis in rats.
AB - The aim of this study was to investigate the impact of L-arginine (nitric oxide
synthase substrate), L-NG-nitro-L-arginine (nitric oxide synthase inhibitor), and
heparin on the pancreas microcirculation, serum IL-6 level and microscopic
alterations of the pancreas in acute pancreatitis in rats. Acute pancreatitis was
induced by 4 i.p. injections of cerulein (15mg/kg). Microcirculatory values were
measured by means of laser Doppler flowmetry 5 h after the first cerulein
injection. Remarkable histopathological changes in the pancreas, including
parenchymal necrosis, an elevation of serum IL-6 level, and a significant drop of
pancreatic capillary perfusion was observed in rats with nitric oxide synthase
inhibition. L-arginine improved the pancreatic microcirculation but worsened the
microscopic alterations within the pancreas. Heparin had a beneficial effect on
the microcirculatory values, serum IL-6 concentration, and morphologic changes.
Authors conclude that inhibition of nitric oxide synthase aggravates acute
pancreatitis. L-arginine treatment improves pancreatic perfusion but potentiates
morphological alterations. Heparin, improving the microcirculation and
inflammatory changes within the pancreatic gland, may be considered as a
promising therapeutic agent in acute pancreatitis.
PMID- 9755295
TI - Single-dose pharmacokinetic study of ciprofloxacin and fleroxacin in healthy
adult Nigerian volunteers.
AB - The kinetics of absorption, distribution and elimination of ciprofloxacin and
fleroxacin (following an intravenous dose of 200 mg), were evaluated in 24 adult
healthy male Nigerian volunteers. Appropriate mathematical models were applied
with the aid of a microcomputer software program for the estimation of the basic
pharmacokinetic parameters. Appropriate statistical tests and profiles formed the
basis for accepting or rejecting a proposed model. For parametric comparisons
between the profile of the two drugs, the null hypothesis of no difference in
their pharmacokinetic profile was proposed. All statistical tests were performed
at a significance level of 95% (alpha = 0.05) and the 95% confidence level was
determined where appropriate. Additionally, the model-independent or stochastic
method of analysis was also employed in the pharmacokinetic evaluation of the
blood level data. The parametric estimates obtained from both methods were
compared. The plasma elimination half-life (t1/2) was estimated as 13.8 +/- 5.5 h
for fleroxacin and 7.5 +/- 4.0 h for ciprofloxacin; the maximal plasma
concentration (Cmax) was 0.8 +/- 0.3 and 2.3 +/- 1.0 mg/l for fleroxacin and
ciprofloxacin, respectively, whilst the volume of distribution (Vd) was 2.5 +/-
1.6 and 0.4 +/- 0.3 liters/kg for fleroxacin and ciprofloxacin, respectively. 71
and 70% of unchanged drug were excreted in urine for fleroxacin and
ciprofloxacin, respectively. With respect to comparative values, the results
confirmed trends already observed in the literature, particularly as regards the
t1/2. However, for fleroxacin there was a significant deviation from the
literature trends with respect to Vd, Cmax and AUC. The results also confirmed
earlier findings, advocating a once-daily dosage schedule for fleroxacin also in
the Negroid population.
PMID- 9755297
TI - Erythromycin resistance in group A beta hemolytic streptococcus.
AB - The incidence of erythromycin resistance and the phenotypic pattern of resistance
have been studied in 130 group A beta-hemolytic streptococcus (GABHS) strains,
isolated from throat swab obtained in children affected by acute
pharyngotonsillitis. A total of 56 (43%) GABHS strains of 130 were resistant to
erythromycin. Among these 56 strains, we found that 7 (12.5%), 18 (32.1%) and 31
(55.3%) showed the cMLS, iMLS and M phenotype, respectively. The iMLS and M
phenotypes appear to be the most widely represented ones. Their low level of
resistance to macrolides could allow the use of the more recent macrolides
characterized by higher tissue concentration which could overcome such a
resistance.
PMID- 9755296
TI - Comparative activity of piperacillin/tazobactam against clinical isolates of
extended-spectrum beta-lactamase-producing Enterobacteriaceae.
AB - beta-Lactam resistance on the part of the Enterobacteriaceae causes serious
therapeutic problems in our institutions due to their production of extended
spectrum beta-lactamases (ESbetaLs). We studied the in vitro activity of beta
lactam/beta-lactamase inhibitor combinations and third-generation cephalosporins
and monobactams against 71 clinically relevant Enterobacteriaceae which produced
TEM- and SHV-derivative ESbetaLs. Of the single drugs and combinations tested,
piperacillin/tazobactam proved to be the most effective. Piperacillin/tazobactam
was highly active against Proteus mirabilis, with minimum inhibitory
concentrations (MICs) ranging from 0.125 to 16 microg/ml; Escherichia coli (MICs
from 2 to 16 microg/ml) and Serratia marcescens (MICs from 4 to 8 microg/ml),
while its activity against Klebsiella pneumoniae ESbetaL producers turned out to
be closely related to the type and the amount of enzyme produced, the MIC ranging
from 1 to 128 microg/ml. The antibacterial activity of piperacillin/tazobactam
was stronger than that of ticarcillin/clavulanate, ceftriaxone, cefotaxime,
ceftazidime and aztreonam, and the combination shared favorable in vitro activity
properties against the ESbetaL producers with imipenem which, however, should be
kept as reserve product.
PMID- 9755298
TI - Mecillinam activity compared to ampicillin, trimethoprim/sulfamethoxazole,
ciprofloxacin and nitrofurantoin against urinary tract isolates of gram-negative
bacilli.
AB - Recent Canadian, American and European studies have reported increased ampicillin
and trimethoprim/sulfamethoxazole resistance among urinary tract isolates of
Escherichia coli. This trend suggests that a reevaluation of first- and second
line therapies for the treatment of community-acquired urinary tract infections
is necessary. Mecillinam, a beta-lactam with preferential activity against gram
negative penicillin binding protein 2 (unlike other beta-lactams which
preferentially bind gram-negative penicillin binding proteins 1a, 1b or 3), may
offer clinically significant activity against ampicillin-resistant and
trimethoprim/sulfamethoxazole-resistant E. coli. To test this assertion, the
activity of mecillinam was compared with ampicillin,
trimethoprim/sulfamethoxazole, nitrofurantoin and ciprofloxacin against 258
consecutive gram-negative urinary tract isolates collected at a Canadian tertiary
care hospital. Mecillinam demonstrated significantly better activity than
ampicillin and trimethoprim/sulfamethoxazole and significantly less activity than
ciprofloxacin and nitrofurantoin against the 258 isolates tested. Against E. coli
isolates specifically, mecillinam was significantly more active than ampicillin
and trimethoprim/sulfamethoxazole (p < 0. 001) and as active as ciprofloxacin and
nitrofurantoin. Mecillinam was active against 91.9% of ampicillin-resistant E.
coli and 95.9% of trimethoprim/sulfamethoxazole-resistant E. coli. We conclude
that mecillinam should be reevaluated for potential use in the treatment of
community-acquired urinary tract infections.
PMID- 9755299
TI - Effects of a new topic amikacin formulation on chemotaxis and release of
profibrotic factors by human monocytes.
AB - Aminoglycosides, widely used because of their large-spectrum antibiotic effects,
should not interfere with the healing process of an ulcer or an infected wound.
We evaluated the effects of amikacin or the excipients present in the topic
formulation BG 90, powder 2. 5% (Boniscontro e Gazzone S.r.l., Rome, Italy), on
human monocyte chemotaxis and the release of profibrotic factors by resting or
lipopolysaccharide (LPS)-activated monocytes. The chemotactic response of
monocytes to zymosan-activated serum is not modified in vitro by pre-incubation
of the cells with amikacin (2 and 10 microg/ml/10(6) cells) or excipients.
Unstimulated monocytes did not secrete appreciable amounts of cytokines. Vice
versa, amikacin-stimulated cells released platelet-derived growth factor AB (PDGF
AB) (about 340 pg/ml), transforming growth factor (TGF)-beta1 (about 10 pg/ml),
and tumour necrosis factor (TNF)-alpha (over 1,100 pg/ml); among excipients, ZnO
and vitamin E induced PDGF-AB release (about 320 and, respectively, 200 pg/ml),
while stimulation of monocyte monolayers by the other excipients did not lead to
appreciable cytokine release. As expected, LPS-activated human monocytes produced
PDGF-AB, TGF-beta1, and TNF-alpha. When monocytes were co-stimulated with LPS and
amikacin, the PDGF-AB and TGF-beta1 values almost overlapped with those from the
stimulation of cells with LPS alone, while TNF-alpha production was slowly
reduced. The results show a stimulating effect of aminoglycoside on the
production of profibrotic factors and, therefore, on the healing process of
wounds in addition to a modulating effect on the production of pro-inflammatory
cytokines like TNF-alpha. Moreover, ZnO and tocopherol (free-radical scavengers),
used as excipients in the topic formulation, induce the release of growth factors
with profibrotic activity (PDGF-AB). Further research is warranted to explore the
effects of this formulation in vivo, verifying whether the association of the
antibiotic with scavengers has a double advantage in topical amikacin: on the one
hand, it could limit the damage from free radicals, and on the other it could
favour tissue healing.
PMID- 9755300
TI - Effects of cefepime, cefixime and ceftibuten on murine gut colonization by
Candida albicans.
AB - Crl:CD1(ICR) BR mice were fed chow containing Candida albicans or regular chow.
Both groups were subsequently given either antibiotics or normal saline. Stool
cultures were performed before, at the end of treatment and 1 week after
treatment, to determine the effect on the stool yeast concentration. Candida
colonized mice treated with cefepime, cefixime or ceftibuten had higher (however
not significantly) counts of the yeast in their stools than control Candida-fed
mice treated with saline. A group of Candida-fed mice were treated with
ceftriaxone, which is known to increase the yeast stool concentration
significantly and served as positive control. Mice fed regular chow and treated
with the study drugs or saline did not have any yeasts in their stools.
Dissemination of Candida did not occur.
PMID- 9755301
TI - Inhibition of malaria-infected erythrocytes by deoxyspergualin: effect on in
vitro growth of malarial cultures.
AB - The effect of deoxyspergualin (DSG) on the K1 strain of human malarial parasite
Plasmodium falciparum in vitro was studied to test a possible new antimalarial
chemotherapy. Hypoxanthine labeled with tritium (3H) was used to assess
macromolecular synthesis. The inhibitory effects of DSG on the parasite peaked
after 72 h of incubation. Parasitemia without DSG treatment was 9%, whereas at a
DSG concentration of more than 156 microg/ml it was less than 1%. The amount of
[3H]hypoxanthine taken up decreased with increasing DSG concentration. DNA
synthesis of malarial activity decreased with increasing DSG concentration. These
findings provide more evidence for the effects of DSG on this malarial parasite.
As in previous in vivo studies done with DSG, the in vitro findings showed that
DSG may be a new antimalarial drug.
PMID- 9755302
TI - Establishment and characterization of cisplatin-resistant human epidermoid
carcinoma cell line, A431 cell.
AB - Cisplatin, cis-diamminedichloroplatinum(II) (CDDP) is one of the most important
anticancer agents, initially producing good responses in various tumors. However,
resistance to this drug often develops in various tumors, and additional
administration decreases its chemotherapeutic efficacy. The precise mechanism of
acquisition of resistance to this drug is still uncertain. However in the present
study, we established two CDDP-resistant sublines A431/CDDP1 and A431/CDDP2 from
human epidermoid carcinoma cell line A431. These resistant sublines were
constituted by exposing A431 cells to a gradually increasing dose of CDDP
(A431/CDDP1), and by mutagenic induction with mutagen (A431/CDDP2). A431/CDDP1
and A431/CDDP2 have developed 3.1 and 2.7 times more resistance to CDDP than the
original A431 cell in terms of IC50. The two CDDP-resistant sublines showed cross
resistance to the CDDP analogue, carboplatin (CBDCA), but not to other
chemotherapeutic drugs such as Adriamycin (ADR) and 5-fluorouracil (5-FU). These
CDDP-resistant sublines were transplanted into nude mice to demonstrate the
resistance to CDDP treatment in vivo. According to the in vitro assay, the
mechanism of resistance in A431/CDDP1 and A431/CDDP2 seems to be based on a
reduction of intracellular accumulation of CDDP, because their platinum
concentration, which is the major component of CDDP, significantly declined. The
established CDDP-resistant sublines may be used in further trials to improve the
understanding of the mechanisms of resistance to CDDP.
PMID- 9755303
TI - Antineoplastic and cytogenetic effects of platinum(II) and palladium(II)
complexes with pyridine-2-carboxyaldehyde-thiosemicarbazone.
AB - The effect of six novel complexes of Pt(II) and Pd(II) with pyridine-2
carboxyaldehyde thiosemicarbazone (HPyTsc) on sister chromatid exchange rate and
human lymphocyte proliferation kinetic was studied. Also, the effect of Pt(II)
and Pd(II) complexes against leukemia P388 was investigated. Among these
compounds, the most effective in inducing cytogenetic and antineoplastic effects
are the complexes [Pd(PyTsc)2] and [Pt(PyTsc)2]. Next in order of magnitude in
inducing antineoplastic and cytogenetic effects is the compound [Pt(HPyTsc)2]Cl2
while the rest, i.e. [Pd(PyTsc)Cl], HPyTsc, [Pd(HPyTsc)2]Cl2, and [Pt(PyTsc)Cl],
show marginal cytogenetic and antineoplastic effects.
PMID- 9755304
TI - New strategies in the treatment of infectious complications in haematology and
oncology: is there a role for out-patient antibiotic treatment of febrile
neutropenia?
AB - Febrile neutropenia is associated with a significant risk of complications and
mortality. Patients with neutropenia secondary to cytostatic chemotherapy who
develop fever are normally admitted to hospital and treated promptly with broad
spectrum antibiotics. Over the last 10 years, chemotherapy for solid tumours has
been shifting out of the hospital setting into the ambit of community-based
oncologists, and out-patient treatment with complex multidrug protocols is
becoming increasingly common. In North America high-dose protocols combined with
peripheral blood stem cell transfusion are already being administered on an out
patient basis. With the increase in the numbers of out-patients undergoing
multidrug chemotherapy, there has been a corresponding rise in the severity and
duration of neutropenia and in the incidence of associated infections. Patients
with neutropenia of short duration (<7 days) and fever are at a relatively low
risk for complications, and in these circumstances, out-patient antibiotic
treatment is an alternative to costly hospitalisation. Drugs, whose antimicrobial
coverage and pharmacokinetics make them particularly suitable for out-patient
treatment of febrile neutropenia, include intravenous and oral quinolones and,
for once-daily dosing, intravenous glycopeptides, ceftriaxone and intravenous
aminoglycosides. Response rates of 60-95% have been achieved with such regimens
in clinical trials, with hospital admission avoided in 75-95% of the cases. There
is no doubt that out-patient treatment improves the quality of life of cancer
patients. In Europe, however, there is a need for randomised clinical trials to
support the establishment of out-patient-based treatment of febrile neutropenia.
Out-patient antibiotic treatment of febrile neutropenia is still not standard
practice, and community-based providers of such treatment must be adequately
equipped and experienced in the management of this condition.
PMID- 9755305
TI - Growth factor receptors as targets for therapy in pediatric brain tumors.
AB - Growth factor receptors (GFRs) have been described as overexpressed in several
types of brain tumors. Overexpression of these transmembrane proteins is
considered to be an important part of tumorigenesis. Genetic as well as
epigenetic modulation of the receptors have to be considered when trying to
understand the role of GFRs in tumors or as targets for tumor therapy. GFR
function can be modulated by membrane components (e.g. gangliosides) or by the
change in receptor glycosylation. These types of changes and the occurrence of
the expression of mutated receptor expressed in tumor cell can result in altered
signaling. In this review, we have focused on GFRs, their expression and
mutations in brain tumors. Recently the correlation between GFR expression and
patient outcome has suggested that these tyrosine kinases and their signaling
might play a decisive role in the course of patients with brain tumors. The
importance of GFRs as possible targets for brain tumor therapy is also discussed.
PMID- 9755306
TI - Headache and Chiari I malformation in the pediatric population.
AB - There has been disagreement regarding surgical intervention in treating pediatric
patients with Chiari I malformation with headache as sole complaint. Therefore,
we retrospectively reviewed our experience over a 6-year period, with patients
less than 5 years of age (mean = 34.8 months) with radiographically confirmed
Chiari I malformation. We identified 7 patients who presented with headaches as
their only complaint. The headaches varied in location and severity. All patients
were treated with posterior fossa decompression and syringosubarachnoid shunt
when indicated. At follow-up, all patients were noted to have rapid clinical
improvement (mean = 11.6 weeks) and remain asymptomatic. Our data suggest that
patients less than 5 years of age with Chiari I malformation benefit from
surgical decompression when presenting with a chief complaint of headache.
PMID- 9755307
TI - Suprasellar germinoma associated with Cushing's disease and diabetes insipidus in
a child.
AB - Cushing's disease is described in a child with a suprasellar germinoma. The
patient presented with all of the classic stigmata of Cushing's disease as well
as diabetes insipidus, but after surgical resection of the lesion was found to
have pathology incompatible with an ACTH-secreting tumor. We believe that this is
the first reported incidence of Cushing's disease associated with a suprasellar
germinoma. The implications of this unusual association are discussed.
PMID- 9755308
TI - Potential prognostic factors of relapse-free survival in childhood optic pathway
glioma: a multivariate analysis.
AB - There is still no consensus on the natural history and optimal management of
optic pathway gliomas (OPG) in children. In order to tackle optimal management
issues, we need to clearly understand the prognostic and confounding factors
affecting relapse of OPG. We propose the use of the Cox proportional hazards (PH)
model in a retrospective study of childhood OPG of 69 children seen from 1977 to
1994. We have developed a comprehensive model capable of multivariate analyses
and handling time-dependencies. Our studies showed that relapse-free survival
improves with increasing age, the presence of neurofibromatosis 1 (NF1), and
chemotherapy and radiotherapy (p < 0.0005). Sex, tumor position and surgery do
not significantly affect survival. Older children with NF1 have extremely good
prognosis. We noted behavior that departs from the strictly proportional hazards
model, but results were inconclusive.
PMID- 9755309
TI - Spinal teratomas versus hamartomas.
PMID- 9755310
TI - An unusual variant of a growing skull fracture in an adolescent.
AB - A great majority of growing skull fractures occur in infancy and earlychildhood.
Since the growth of brain is necessary as a driving force for these lesions to
occur, almost all reported cases have been before the first 3 years of life.
Although a number of uncommon locations, such as basiooccipital and skull base
areas, have been reported, they are commonly located on calvaria. The authors
report a growing skull fracture on the orbital roof in a 16-year-old female
admitted to hospital with complaints of headache and seizures. She had had an
orbital trauma 8 years before. CT scan revealed a hypodense lesion in the right
frontal lobe and a diastatic fracture line on the right orbital roof. A right
craniotomy was performed. Excision of arachnoid loculations and duraplasty were
carried out. This is an unusual condition with respect to the location of the
lesion, as well as the age of the patient.
PMID- 9755311
TI - Treatment of intracranial ependymoma by surgery alone.
AB - OBJECTIVE: This study aimed to determine the safety of deferring radiotherapy in
pediatric intracranial ependymoma following a radiographically confirmed gross
total resection in patients with localized disease. METHODS: Children over age 3
were recruited prospectively from 1990 to 1997, following a surgical impression
and radiologic confirmation of a gross total resection of an intracranial
ependymoma. RESULTS: 10/32 cases of intracranial ependymomas were both eligible
and gave consent. 7 remain free of disease without further intervention. 3
recurred, 2 were salvaged with surgery and radiotherapy, none died. CONCLUSIONS:
Deferral of radiotherapy following gross total resection alone is a safe option
in supratentorial ependymomas. The pattern of recurrence is usually local and
patients may be salvaged with additional surgery with or without radiotherapy.
PMID- 9755312
TI - 15-year-old young woman with morning headaches.
PMID- 9755314
TI - Spinal teratomas versus hamartomas
PMID- 9755313
TI - Ventriculoperitoneal shunt obstruction presenting as apnea and bradycardia.
PMID- 9755315
TI - Intraoperative monitoring.
PMID- 9755316
TI - Bisphenol A diglycidyl ether as a potential metabolic source of bisphenol A.
PMID- 9755317
TI - Surgical results after soft system stabilization of the lumbar spine in
degenerative disc disease--long-term results.
AB - After having reported preliminary results of soft system stabilization according
to Graf in a series of 27 patients with degenerative disc disease of the lumbar
spine in early 1995 the authors report long term clinical and radiological
results of this patient series (n = 25). At a mean period of postoperative
observation of 50 months excellent, good, satisfactory, moderate and poor results
were obtained in 62, 9%, 11, 1% and 11, 1%, 7, 4% and 7, 4% of the patients,
respectively. The well-known phenomenon of loss of disc height at the level of
posterolateral fusion and instrumentation as well as overcharge of adjacent
segments were not observed after soft system stabilization. Regional as well as
global lumbar lordosis were maintained and, although statistically not
significant, an increase of intervertebral distance was observed in adjacent
segments in flexion of the lumbar spine. These phenomena might represent
pressurization of instrumented as well as adjacent discs after the insertion of
ligament prostheses. It is the impression of the authors, that the Graf technique
leads to good surgical results in degenerative disc disease with destabilization
of lumbar motion segment(s) if the following criteria are strictly respected: 1.
No or only mild arthrotic changes of the facet joints 2. Preferably minor disc
degeneration/only mild loss of intervertebral distance. 3. Well trained low back
muscles and 4. A clear-cut, repeatedly demonstrated pain-relief on trial
anaesthesia of the corresponding articular nerves and while wearing a probatory
jacket.
PMID- 9755318
TI - Radiological investigations and intra-operative evoked potentials for the
diagnosis of nerve root avulsion: evaluation of both modalities by intradural
root inspection.
AB - Fourteen patients with traumatic brachial plexus injuries underwent intradural
inspection of cervical nerve roots to evaluate radiological and intra-operative
electrophysiological findings concerning cervical nerve root avulsion from the
spinal cord. Four neurosurgeons of our department assessed independently from
each other both myelography and CT-myelography concerning intradural nerve root
lesions. Each neurosurgeon assessed a total of 26 cervical nerve roots. Two
investigators assessed 6/26 and 2 investigators 7/26 nerve roots falsely
concerning ventral or/and dorsal root lesions compared with the findings on
intradural inspection (23% and 27% false findings). There was a considerable
variance concerning the assessibility and findings among the 4 neurosurgeons.
Reconstructive surgery was performed after a mean interval of 6.5 months
following trauma and 2 weeks following intradural inspection. After exposure of
the brachial plexus and the cervical nerve roots in question via a ventral
approach, 13 cervical nerve roots were stimulated electrically close to the
neuroforamen and cortical evoked potentials (root-SEPs) were recorded from the
contralateral postcentral region. All 5 roots with SEPs were intact (no root
lesion) and all 8 roots without SEPs showed interrupted (ventral or/and dorsal)
rootlets on intradural inspection. Our results demonstrate that false
radiological findings concerning root lesions are possible. Intra-operative root
SEPs seem to be a useful aid for evaluation of cervical nerve root lesions.
However, more electrophysiological data are necessary to ascertain, if this
modality is able to replace intradural inspection in unclear radiological cases
in the future.
PMID- 9755319
TI - Somatosensory and motor evoked potentials in patients with tumours in the spinal
canal.
AB - Motor and sensory evoked potentials were recorded in 27 patients with expanding
spinal tumour. The patients were divided into 2 groups: I. tumours at the level
of the spinal cord and II. at the level of the cauda equina. On the basis of the
localization of the tumour, midline and lateral subgroups were distinguished. The
latencies of motor evoked potentials were prolonged in most of the patients, even
those without paresis, in both groups. The motor evoked potentials detected
subclinical motor lesions in 7 patients. All patients but one manifested sensory
deficits, which could not be shown with the somatosensory evoked potentials.
Significantly more prolonged cortical motor latencies were found in most of the
patients with a laterally located tumour on the tumour side than contralaterally,
whereas in somatosensory evoked potentials this difference was not apparent. On
the basis of these observations, we concluded that motor evoked potentials, 1.
could more reliably detect the neural deficit than somatosensory evoked
potentials; 2. could show the side where the tumour was located; 3. proved useful
in the detection of subclinical motor lesions. The general conclusion may be
drawn that this electrophysiological method can provide useful information for
the surgeon.
PMID- 9755320
TI - Demonstration of the optic pathway in sellar/juxtasellar tumours with visual
disturbance on MR imaging.
AB - OBJECTIVE: To prospectively compare the demonstration of the intracranial optic
pathway in patients with sellar/juxtasellar tumours and with clinical evidence of
visual disturbance using either spoiled gradient recalled acquisition in steady
state (SPGR) or conventional spin echo (CSE) T1-weighted imaging. MATERIALS AND
METHODS: We studied 108 patients with sellar/juxtasellar tumours presenting
visual disturbance. Visualization of the optic pathway (nerves, chiasm, tracts)
was compared between CSE T1-weighted coronal image and SPGR coronal image. In 18
patients, SPGR imaging was performed before and after administration of Gd-DTPA
and visualization of the optic pathway was compared. RESULTS: On CSE T1-weighted
coronal images of 108 patients with visual disturbance, the rates for
visualization of the optic nerves, chiasms and tracts were 50%, 77.8% and 89.8%
respectively. In contrast, on SPGR coronal image the rates were 80.6%, 96.3% and
92.6% respectively. The rates of visualization of the optic pathway were greater
in non-enhanced that in those with enhancement. The rates of visualization in
patients with recurrent tumours were less than those in patients with primary
tumours. The rate of visualization of optic nerves in patients with meningioma
was less than in patients with pituitary adenoma, craniopharyngioma or Rathke
cleft cyst. CONCLUSION: The rate of visualization of optic pathway structures on
SPGR imaging (without enhancement) is greater than that on CSE T1-weighted
imaging. It is important to understand the accurate position of the optic
pathways with using new MR modality especially in surgical planning for lesions
around the sella turcica.
PMID- 9755321
TI - Gamma-knife radiosurgery for brain metastases of renal cell carcinoma: results in
23 patients.
AB - From Jan. 1993 to Sept. 1995 23 patients suffering from brain metastases from
renal cell carcinoma were treated with the Leksell Gamma Knife at the University
of Vienna. At the time of diagnosis 13 patients had single and 10 patients
presented with multiple metastatic lesions with a total of 44 metastases in MRI
scans. Median tumour volume was 5500 cmm (range 100-24000 cmm). Predominant
neurological symptoms and signs were different forms of hemiparesis, focal and
generalized seizures, cognitive deficit, headache, dizziness, ataxia and CN XII
paresis. Fourteen patients received Gamma Knife Radiosurgery (GKRS) with a median
dose of 22 Gy (range 8-30 Gy) at the tumour margin. Nine patients underwent a
combined treatment of a radiosurgical boost with a median dose of 18 Gy (range 10
22 Gy) at the tumour margin followed by Whole Brain Radiotherapy (total dose 30
Gy/2 weeks). In 20 patients tumour volume reduction up to 30% of the primary
tumour volume was found after 4 weeks, evaluated on CT or MRI. A total remission
was seen in 4 cases 3 months after GKRS. We achieved a local tumour control of
96%. Rapid neurological improvement after GKRS was seen in 17 patients. The
median survival time was 11 months; the one-year actual survival in this
unselected group was 48%. Five long term survivors were still alive, 18 patients
had subsequently died, 15 of them of general tumour progression. GKRS induces a
significant tumour remission accompanied by rapid neurological improvement and
therefore provides the opportunity for extended high quality survival. Neither
local tumour control was improved nor CNS relapse free survival was prolonged
significantly by additional WBRT.
PMID- 9755322
TI - Choroid plexus carcinoma in infants: report of two cases and review of the
literature.
AB - Choroid plexus carcinoma (CPC) is a rare malignant brain tumour which occurs
predominantly in childhood. We present the cases of two infants with CPC. One, a
6-month-old boy with the tumour in the right lateral ventricle, who died of a
postoperative intracranial haemorrhage and severe gastrointestinal bleeding, and
the other, a 9-month-old boy with the tumour in the fourth ventricle, who has
been well without recurrence for 12 months after total removal in combination
with chemotherapy using cisplatin and VP-16 and local radiotherapy. In the 54 CPC
cases in children under 2 years of age including our 2 cases in which the
clinical results were described in the literature since 1983, tumour location
(lateral ventricle, p = 0.0225), surgery (gross total resection, p = 0.0447), and
chemotherapy (yes, p = 0.0010) were revealed to be significant positive
prognostic factors by the univariate analysis using the log rank test, and
surgery (gross total removal, p = 0.0259) and chemotherapy (yes, p = 0.0016) were
independent, significant positive prognostic factors in the multivariate analysis
using the Cox proportional hazard regression model. Although there is a risk in
doing a statistical analysis of other people's reports, these results suggest
that, at present, the gross total removal of the tumour with intensive
chemotherapy is the best choice of initial treatment for young children with CPC,
and that radiotherapy should be considered for patients after 24 months of age
and/or should be performed locally.
PMID- 9755323
TI - Prediction of vertebral artery compression in patients with hemifacial spasm
using oblique sagittal MR imaging.
AB - To discriminate between the various compressing vessels of the facial nerves in
patients with hemifacial spasm, pre-operative oblique sagittal gradient-echo MR
imaging was performed. Forty-two patients underwent pre-operative MR imaging and
microvascular decompression. The MR images were divided according to findings
into three groups as follows: Group A, a thick and/or long high-intensity line
along the root exit zone (REZ) of the facial nerve; Group B, a thin and/or short
high-intensity line along the REZ; and Group C, an unreliable image around the
REZ. Fifteen images were classified as Group A, 19 as Group B, and 8 as Group C.
In Group A, vertebral artery (VA) compression was confirmed intra-operatively in
12 cases and posterior inferior cerebellar artery (PICA) or anterior inferior
cerebellar artery (AICA) compression in 3. In Group B, PICA or AICA compression
was confirmed intra-operatively in all cases. In Group C, PICA or AICA
compression was confirmed intra-operatively in 7 cases and no compression in one.
In all cases of VA compression of the facial nerve, the oblique sagittal gradient
echo images demonstrated a thick and/or long high intensity line along the REZ.
Oblique sagittal gradient-echo MR imaging is a useful preoperative planning aid,
which can predict the possibility of VA compression prior to microvascular
decompression for hemifacial spasm.
PMID- 9755324
TI - Cerebral blood flow velocities after subarachnoid haemorrhage in relation to the
amount of blood clots in the initial computed tomography.
AB - In 72 patients with acute subarachnoid haemorrhage (SAH) the relationship between
the amount of subarachnoid blood clots detected by initial cranial computed
tomography (CCT) up to 48 hours after bleeding and the later development of
vasospasm, established by blood flow velocity measurement with transcranial
Doppler ultrasound (TCD) was investigated. The serial Doppler examinations
started within the first 72 hours after SAH and were carried out every second day
up to three weeks. Each Doppler recording was accompanied by a neurological
examination. Patients classified as Hunt and Hess grade V were excluded from the
study. All patients with remarkable brain oedema in CCT or with intracranial
pressure above 25 mmHg were also excluded. Because of the well known age
dependence of vasospasm after SAH, two age groups were formed. A statistically
significant correlation (p > 0.05) between blood flow velocities and blood load
after SAH was not found. The mean age of the investigated 72 individuals was 48.9
years (14 up to 76 years). 47 patients were younger than 56 years. Linear
regression analysis indicated a correlation with a quite low significance level
(r = 0.350, p < 0.025) between TCD blood flow velocities and blood load in CCT in
these younger subjects. No significant correlation (p > 0.05) between these two
variables could be established in the 25 patients older than 55 years. In a
second step an intra-individual comparison of side-to-side differences in TCD and
CCT was made. There were no significant differences in blood flow velocities
between subjects with or without side-to-side differences in cisternal blood
load. It is concluded that the amount of blood visible on initial CCT after SAH
is not a powerful predictor of cerebral blood flow velocities measured by TCD.
PMID- 9755325
TI - Thrombin activity in CSF after SAH is correlated with the degree of SAH the
persistence of subarachnoid clot and the development of vasospasm.
AB - We previously reported that the coagulation system in cerebrospinal fluid (CSF)
is strongly activated in the early stage of a subarachnoid haemorrhage (SAH). We
evaluated the relationship among thrombin activity, degree of SAH, amount of
clearance of SAH, and vasospasm. The CSF levels of fibrinopeptide A (FPA) were
measured by radio-immunoassay in 36 SAH patients, who were diagnosed by
computerized tomography (CT) within 12 hours and on whom surgery was performed
within 48 hours. Clearance of SAH (%) was evaluated as the size of the clot in
the basal cistern visualized between the initial and postoperative CT. The mean
level of FPA in the patients of Group 3 (Fisher's CT classification) (182.2
ng/ml) was significantly higher than those in the patients of Group 2 (36.2
ng/ml). There was a significant difference in the mean level of FPA between
patients with (47.6 ng/ml) and without infarction (408.3 ng/ml). In 18 of the 27
patients of Group 3 for whom the clearance of the SAH was determined, the
patients showing a lower clearance rate (< 50%) of SAH demonstrated a
significantly higher rate of infarction and a significantly higher level of FPA
(466.6 ng/ml) than did the patients with a higher clearance rate (> 50%) of SAH
(79.2 ng/ml). These results suggest that, the thrombin activity in CSF is
correlated with the degree of SAH, the persistence of subarachnoid clot and the
development of vasospasm.
PMID- 9755326
TI - No specific brain protection against thermal stress in fever.
AB - Knowledge about human brain temperature is still very limited, despite evidence
demonstrating the critical influence of mild increases in temperature on the
ischaemic brain. It has been suggested that in passive and exercise hyperthermia
the brain may be protected against thermal damage by a mechanism of selective
brain cooling (SBC). It is said to bring about suppression of the temperature of
the brain, rendering it significantly lower than trunk and arterial blood
temperature. Yet very little is known about the possible role of this mechanism
in fever, a condition fundamentally different from "physiological" hyperthermia,
especially when it occurs in brain-damaged patients. In our investigation we
retrospectively analysed the results of direct recordings of cerebral temperature
within the subdural space (Tsd) and within the brain parenchyma (Tbr-16 cases) in
63 unanaesthetized patients following neurosurgical procedures, including 23 with
fever > 38 degrees C. The difference between trunk temperature, measured in the
rectum (Tre) or in the oesophagus (Tes), and the intracranial temperature, were
calculated in all subjects. A statistically significant reduction of these
differences, in step with increasing fever, would be compatible with
demonstrating a process of selective brain cooling. The offsets Tre-Tsd, Tre-Tbr,
and Tes-Tsd were plotted against Tre over a wide range of body temperature and
near zero correlation was found. This finding suggests that brain temperature in
fever was not selectively suppressed by any specific thermolytic mechanism and
that dissipation of the main bulk of cerebral metabolic heat both in normothermia
and in fever depends on heat uptake by arterial blood. The results suggest that
the brain in fever can be seriously jeopardized by heat stress and no specific
cooling mechanism exists, to reduce it below body temperature in feverish
neurosurgical patients. Tbr and/or Tsd remained the highest body temperature in
14 out of the 23 patients during fever.
PMID- 9755327
TI - Intraoperative hypothermia and ventricular shunt infections.
AB - Several recent studies have demonstrated a relationship between intraoperative
hypothermia and postoperative infection. A study was therefore conducted to
evaluate the relationship between intraoperative hypothermia and ventricular
shunt infections. Sixty-eight children who underwent ventricular shunt placement,
including revisions, over a six year period subsequently developed a shunt
infection (overall shunt infection rate of 5%). Mean age was 8 years (range,
neonate to 20 years). The last 74 children who underwent ventricular shunt
placement without subsequent infection served as a comparison group. The
anesthetic records of all cases were reviewed to determine the lowest core
temperature recorded during the surgical procedure. The lowest core temperature
varied from 33.9 degrees C to 37.7 degrees C (mean 36.0 degrees C). Hypothermia
was defined as a temperature less than 35.1 degrees C. No relationship was found
between hypothermia and the subsequent occurrence of a shunt infection (P =
0.45). When those children less than 2 years old were excluded from analysis,
there was a trend towards statistical significance (P = 0.07). In summary, this
study failed to show any significant relationship between the occurrence of
intraoperative hypothermia and subsequent ventriculoperitoneal shunt infection in
a group of pediatric patients.
PMID- 9755328
TI - Low rate of shunt revision in tumoural obstructive hydrocephalus.
AB - The authors calculated the shunt revision rate for 77 consecutive patients with
tumoural obstructive hydrocephalus. At a mean follow up of 23.7 months, the
annual revision rate was 0.06 which is significantly lower than the annual
revision rate of 0.39 for other hydrocephalic patients treated during the same
period. Shunted patients who had total excision of their lesions had a
significantly lower revision rate than patients who had a partial excision or a
biopsy. It is therefore, suggested that cases with tumoural obstructive
hydrocephalus may represent a subset of hydrocephalic patients who are associated
with a relatively low risk of shunt complications. The observation has to be
addressed when the role of endoscopic third ventriculostomy in these patients is
being considered.
PMID- 9755329
TI - Cerebral blood flow velocity and vasomotor reactivity before and after shunting
surgery in patients with normal pressure hydrocephalus.
AB - The purpose of this study was to evaluate pre- and post-shunting haemodynamic
changes and their correlation with the clinical results in normal pressure
hydrocephalus (NPH). Accordingly, eleven demented patients with clinical signs
suggestive of NPH received examinations of cerebral blood flow velocity (BFV) and
vasomotor reactivity (VMR) by transcranial Doppler sonography with carbogen
testing before and after shunt treatment. Computerized tomography (CT), clinical
assessment and neuropsychological grading were performed prior to and at 3 months
following surgery. A control group consisting of 10 patients was included to
establish baseline data. The pre-operative CBF studies in the anterior cerebral
artery (ACA) and the middle cerebral artery (MCA) revealed the NPH patients did
not have significant decreases of BFVs, but had significant decreases of carbogen
VMR (P < 0.05). After shunting, there were no significant changes of the BFVs as
compared with the pre-shunting data. The post-shunting VMR of the ACA was
significantly higher than the pre-shunting one (p < 0.05), but there was no
variation in that of the MCA. Both the values of post-shunting VMR in ACA and the
post-shunting increase in VMR in MCA of the 7 shunt-responsive patients who
improved mentally and in other symptoms were significantly higher than those of
patients without improvement (p < 0.05). In addition, the five patients with gait
improvement showed significantly higher values of post-shunting VMR of ACA and
the post-shunting increase of VMR for both ACA and MCA when compared with those
patients without gait improvement (p < 0.05, respectively). Our study supports
the view that patients with NPH had various degrees of impaired VMR in both the
ACA and the MCA, but showed insignificant reduction in BFVs, indicating a
compensatory mechanism of CBF over time to accommodate the subnormal state of
cerebral perfusion pressure. Shunt placement would improve the VMR in responsive
patients. Postoperatively, an increase of VMR tends to accompany improvement of
the functional state: that in the MCA alone is associated with symptomatic
improvement in mental function and that increase in VMR in both the ACA and the
MCA with improvement in gait, respectively.
PMID- 9755330
TI - Estimation of volume doubling time and cell loss in an experimental rat glioma
model in vivo.
AB - We estimated the volume doubling time (Vd) of the ethyl-nitrosourea-induced rat
glioma by serial magnetic resonance imaging, and the results were compared with
potential doubling time (Tp) determined immunohistochemically. Vd ranged from 3.3
to 29.2 days (11.3 +/- 7.74) and Tp ranged from 2.3 to 13.3 days (6.81 +/- 3.33).
Each tumour showed a wide range of bromodeoxyuridine (BUdR) labelling indices
(LI), however, Vd and Tp correlated well with BUdR-LI. Vd was estimated as 17.6 x
BUdR-LI-0.63 (R = -0.76, P < 0.001, n = 13) and Tp was estimated as 22.6 x BUdR
LI-1.02 (R = -0.92, P < 0.0001, n = 12). In addition, we compared the apoptotic
indices (AI), determined by terminal deoxynucleotidyltransferase (Tdt)-mediated
biotinylated dUTP-biotin nick-end labelling (TUNEL) techniques, with BUdR-LI and
mitoses indices (MI). The results were: AI = 0.23 + 0.25Ln(BUdR-LI) (R = 0.971, n
= 8, P < 0.0001) and AI = 1.05 + 0.29Ln(MI) (R = 0.937, n = 8, P < 0.001). Cell
loss factors (CLF) also correlated well with BUdR-LI and MI. However, CLF
calculated from Tp and Vd were lower than the values previously presumed,
probably because of shorter Vd than true doubling time for tumour cell
population. These results suggest that even malignant tumours retain a mechanism
of adjusting their growth at least partly.
PMID- 9755331
TI - Repair of dural defects in awkward areas-technical note.
AB - Dural tears located at the base of the skull are difficult to repair due to the
difficulties in the appropriate access and the fragility of the dura in such
areas. In our experience the biggest problem when attempting to perform a dural
repair in a deep narrow field is not to place the stitches, but rather to set the
knots. A newly designed, easy-to-learn technique has been developed for dural
closure in these situations. We present here a new technique for dural suturing
of special interest when the space available is limited. In our hands it is
possible to obtain a watertight dural closure in most microsurgical operations
performed through a small hole and/or into a narrow, deep surgical field. These
techniques can also be applied during a secondary procedure following development
of a postoperative CSF leak. While simple and easy to learn, these techniques
require practice in the laboratory setting before clinical application.
PMID- 9755332
TI - A new coated bipolar coagulator: technical note.
AB - BACKGROUND: Sometimes charring or popping occurs and the bipolar blades get stuck
to the vessel. METHODS: The tips of one of the many commercially available
bipolar forceps were coated in a striped manner with Teflon--50 micro in
thickness. RESULTS: The new bipolar coagulator coated with Teflon reduced the
incidence of tissue sticking. CONCLUSIONS: Experience with this instrument was
still quite limited, but preliminary results were promising.
PMID- 9755333
TI - Unusual clinical presentation of a meningeal melanocytoma with seizures: case
report and review of the literature.
AB - The 17th case of an intracranial meningeal melanocytoma is presented in a 67-year
old man. It is the 6th melanocytoma arising from the cavum Meckeli and the first
presenting with seizures. Surgical removal was curative for a follow up period of
32 months. Besides the clinical and neuroradiological presentation, the
histological, ultrastructural and immunohistochemical features are described. A
review of the literature including cases with malignant transformation is given
and differential diagnostic problems are discussed.
PMID- 9755334
TI - Ruptured aneurysm at the bifurcation of the posterior meningeal artery from the
proximal posterior inferior cerebellar artery.
PMID- 9755335
TI - Turcot's syndrome presenting with medulloblastoma and familiar adenomatous
polyposis: a case report and review of the literature.
PMID- 9755336
TI - Internal carotid artery injury and occlusion from camel collision.
PMID- 9755338
TI - Interleukin-12: a cytokine at the interface of inflammation and immunity.
PMID- 9755337
TI - Biology of the interleukin-2 receptor.
AB - Studies of the biology of the IL-2 receptor have played a major part in
establishing several of the fundamental principles that govern our current
understanding of immunology. Chief among these is the contribution made by
lymphokines to regulation of the interactions among vast numbers of lymphocytes,
comprising a number of functionally distinct lineages. These soluble mediators
likely act locally, within the context of the microanatomic organization of the
primary and secondary lymphoid organs, where, in combination with signals
generated by direct membrane-membrane interactions, a wide spectrum of cell fate
decisions is influenced. The properties of IL-2 as a T-cell growth factor spawned
the view that IL-2 worked in vivo to promote clonal T-cell expansion during
immune responses. Over time, this singular view has suffered from increasing
appreciation that the biologic effects of IL-2R signals are much more complex
than simply mediating T-cell growth: depending on the set of conditions, IL-2R
signals may also promote cell survival, effector function, and apoptosis. These
sometimes contradictory effects underscore the fact that a diversity of
intracellular signaling pathways are potentially activated by IL-2R. Furthermore,
cell fate decisions are based on the integration of multiple signals received by
a lymphocyte from the environment; IL-2R signals can thus be regarded as one
input to this integration process. In part because IL-2 was first identified as a
T-cell growth factor, the major focus of investigation in IL-R2 signaling has
been on the mechanism of mitogenic effects in cultured cell lines. Three critical
events have been identified in the generation of the IL-2R signal for cell cycle
progression, including heterodimerization of the cytoplasmic domains of the IL-2R
beta and gamma(c) chains, activation of the tyrosine kinase Jak3, and
phosphorylation of tyrosine residues on the IL-2R beta chain. These proximal
events led to the creation of an activated receptor complex, to which various
cytoplasmic signaling molecules are recruited and become substrates for
regulatory enzymes (especially tyrosine kinases) that are associated with the
receptor. One intriguing outcome of the IL-2R signaling studies performed in cell
lines is the apparent functional redundancy of the A and H regions of IL-2R beta,
and their corresponding downstream pathways, with respect to the proliferative
response. Why should the receptor complex induce cell proliferation through more
than one mechanism or pathway? One possibility is that this redundancy is an
unusual property of cultured cell lines and that primary lymphocytes require
signals from both the A and the H regions of IL-2R beta for optimal proliferative
responses in vivo. An alternative possibility is that the A and H regions of IL
2R beta are only redundant with respect to proliferation and that each region
plays a unique and essential role in regulating other aspects of lymphocyte
physiology. As examples, the A or H region could prove to be important for
regulating the sensitivity of lymphocytes to AICD or for promoting the
development of NK cells. These issues may be resolved by reconstituting IL-2R
beta-/-mice with A-and H-deleted forms of the receptor chain and analyzing the
effect on lymphocyte development and function in vivo. In addition to the
redundant nature of the A and H regions, there remains a large number of
biochemical activities mediated by the IL-2R for which no clear physiological
role has been identified. Therefore, the circumstances are ripe for discovering
new connections between molecular signaling events activated by the IL-2R and the
regulation of immune physiology. Translating biochemical studies of Il-2R
function into an understanding of how these signals regulate the immune system
has been facilitated by the identification of natural mutations in IL-2R
components in humans with immunodeficiency and by the generation of mice with
targeted mutations in these gen
PMID- 9755339
TI - Recent progress on the regulation of apoptosis by Bcl-2 family members.
PMID- 9755340
TI - Interleukin-18: a novel cytokine that augments both innate and acquired immunity.
PMID- 9755341
TI - CD4+ T-cell induction and effector functions: a comparison of immunity against
soluble antigens and viral infections.
PMID- 9755342
TI - Current views in intracellular transport: insights from studies in immunology.
PMID- 9755343
TI - Phylogenetic emergence and molecular evolution of the immunoglobulin family.
PMID- 9755345
TI - Characteristics of successful and unsuccessful dieters: an application of signal
detection methodology.
AB - Signal detection methods were used to identify predictors of successful weight
loss in 177 mildly to moderately overweight women and men assigned to one of two
weight-loss programs. Predictors included initial demographic, physiological,
behavioral, and psychosocial characteristics, and program type (e.g. diet-only
and diet-plus-exercise). Successful weight loss was defined as a loss of at least
two units of body mass index at one year. Four subgroups were identified.
Participants in the diet-plus-exercise program who were initially more satisfied
with their bodies and did not have a history of repeated weight loss were most
likely to succeed (63% succeeded). In contrast, participants assigned to the diet
plus-exercise program who were either extremely dissatisfied with their bodies or
who had a history of repeated weight loss were at similar risk for failure as
participants in the diet-only program (only 26% to 35% succeeded). The results
underscore the potential utility of exploring these subgroups further to inform
the development of new treatment strategies to increase the likelihood of
success.
PMID- 9755344
TI - Current insights into the "antiphospholipid" syndrome: clinical, immunological,
and molecular aspects.
AB - Advances in defining the target antigen(s) for the autoantibodies in the APS
highlight the inadequacies of the current classification of these autoantibodies
into anticardiolipin and LA antibodies. The discovery that beta 2GPI is the
target antigen for the autoantibodies detected in solid-phase immunoassays has
opened a number of areas of research linking these autoantibodies to
atherogenesis and thrombus formation. Although the role of beta 2GPI in the
regulation of blood coagulation in unclear, current evidence suggests that anti
beta 2GPI antibodies interfere with its "normal" role and appear to promote a
procoagulant tendency. The expansion of research in this area and the diversity
of the clinical manifestations of patients with APS have resulted in the
inclusion of molecular biologists and pharmaceutical companies joining
immunologists, hematologists, rheumatologists, obstetricians, neurologists,
vascular surgeons, and protein and lipid biochemists in attempting to understand
the pathophysiology of this condition. Although the published literature may
result in conflicting results and introduce new controversies, developing
standardized laboratory methods and extrapolation of in vitro experimental
results to the vivo situation will advance our understanding of the regulation of
the immune system and its interaction with normal hemostatic mechanisms. Since
the authors' last review in 1991, the study and understanding of the
pathophysiology of APS have evolved from lipid biochemistry to molecular
techniques that may eventually provide specific therapies for the clinical
manifestations of this condition. Although current treatment has improved the
morbidity associated with this condition, especially in improving pregnancy
outcomes, future therapies, as outlined in this review, may specifically address
the biological abnormalities and have fewer side effects. Better diagnostic
tools, such as magnetic resonance imaging with perfusion studies, will allow the
study of the true incidence and prevalence of vascular flow changes/tissue
ischemia and infarction associated with aPL antibodies and help determine
treatment and prophylaxis for APS patients. APS is still the only hypercoagulable
condition where both arterial and venous beds can be affected independently or in
the same individual.
PMID- 9755346
TI - The impact of a brief problem-solving training intervention for relatives of
recently diagnosed breast cancer patients.
AB - Previous studies have found high levels of psychological distress in women who
have a family history of breast cancer. We evaluated a brief Problem-Solving
Training (PST) intervention designed to reduce distress among women with a first
degree relative recently diagnosed with this disease. Participants were randomly
assigned to either the PST group (N = 144) or a General Health Counseling (GHC)
control group (N = 197). At baseline, these groups did not differ on any
sociodemographic, risk factor, or psychological distress variables. We evaluated
the impact of PST, relative to GHC, at the three-month follow-up assessment using
a 2 (treatment group) x 2 (time of assessment) mixed factor analysis of variance
(ANOVA). Although there were significant decreases in both cancer-specific and
general distress in both the PST and GHC groups, the magnitude of these decreases
did not differ. However, when PST participants were divided into those who
regularly practiced the PST techniques and those who did not, significant
differences emerged. Participants who regularly practiced the PST techniques had
significantly greater decreases in cancer-specific distress [Impact of Event
Scale (IEs) intrusion and avoidance subscales] compared to infrequent practicers
and GHC participants. Effects on general distress were not found. Additional
studies are needed to identify ways to promote the practice of PST techniques and
to evaluate other psychosocial interventions for female relatives of breast
cancer patients.
PMID- 9755347
TI - Body images and obesity risk among black females: a review of the literature.
AB - The prevalence of obesity among Black women has reached epidemic proportions.
Some researchers have suggested that the body images of Black females may
contribute to their high risk for obesity by inhibiting motivation for weight
control. While a number of empirical studies have examined the body images of
Black females, findings are complex and at times, inconsistent. For example, some
studies show that Black females consider overweight bodies more attractive, while
other studies show that Black females prefer normal-weight bodies. Divergent
findings may be due, in part, to the multidimensional nature of body image.
Inconsistencies may also be due to differences between the Black females sampled.
Methodological problems, including the use of measures that have been validated
among Black females, the use of various weight-for-height standards, and the
inconsistent analyses of or lack of physiological data, also may contribute to
conflicting results. This review addresses the complexity of body image findings
among a heterogeneous Black female population and the relationship between their
body images and obesity risk. Implications for effective obesity treatment
programs and suggestions for improvements in future body image studies are also
discussed.
PMID- 9755348
TI - Reliability of the timeline follow-back sexual behavior interview.
AB - The reliability of self-reported sexual behavior is a question of utmost
importance to human immunodeficiency virus (HIV) prevention research. The
Timeline Follow-Back (TLFB) interview, which was developed to assess alcohol
consumption on the event level, incorporates recall-enhancing techniques that
result in reliable information. In this study, the TLFB interview was adapted to
assess HIV-related sexual behaviors and their antecedents, and its reliability
was assessed. The interview was administered to 110 participants (46% women, M
age = 19.7; range = 18-41), and 58 participants who reported sexual behavior
during the previous three months returned one week later for a second interview.
Test-retest intraclass correlations (rho) from the TLFB protocol showed that all
sexual behaviors were reported reliably (rho range = .86 to .97, median = .96).
Bootstrapping, a nonparametric statistical technique, was used for significance
testing in the reliability analyses. Reliability was equivalent across each of
the three months assessed with the TLFB and was equivalent to conventional
assessment methods (i.e. single-item questions). These findings show that the
TLFB sexual behavior interview provides reliable reports of sexual behavior over
three months and yields event-level data that are extremely valuable for sexual
behavior and HIV-prevention research.
PMID- 9755349
TI - The effect of pain on memory for affective words.
AB - Memory is a key cognitive variable in pain management, but lacks extensive
research. This study is a replication and extension of Seltzer and Yarczower's
investigation of pain's influence on memory for affective words, which found
fewer positive words and more negative words recalled if subjects were in acute
pain (versus no pain). In the present study, two experiments were conducted: one
with a recall memory test and one with a recognition memory test. One hundred
sixty undergraduate subjects were randomly placed in one of four groups: two
groups had the same condition (pain or no pain) for both the encoding task and
memory test, and two groups had mixed conditions (pain at encoding-no pain at
memory test or no pain at encoding-pain at memory test). Pain was induced by 0
degrees-2 degrees C water immersion. At encoding, subjects categorized words by
judging them as either positive or negative. Results of both experiments show
that pain impairs memory. In neither experiment were differences found on memory
for positive and negative words. These results do not support Seltzer and
Yarczower's discriminative effects of pain on word category, but they are
consistent with other research using acute pain manipulations and chronic pain
populations, suggesting that pain interferes with memory. It is hypothesized that
pain depletes scarce attentional resources, thereby interfering with concurrent
cognitive tasks such as thinking, reasoning, and remembering.
PMID- 9755350
TI - Compliance with inhaled medications: the relationship between diary and
electronic monitor.
AB - Self-report is a frequently-used method of assessing compliance with prescribed
medications in patients with chronic illnesses. Most researchers agree, however,
that self-report misrepresents patient adherence to regimen prescription. In this
randomized, controlled study evaluating inhaler medication compliance, diary data
was compared to electronic monitoring in 55 adults with asthma. Subjects
randomized to the treatment group received a six-week self-management program. An
electronic monitor, the MDI Chronolog, was used in this study to assess inhaler
use. The MDI Chronolog records the date and time of each inhaled activation. The
self-report measure used was a daily asthma diary. Subjects were asked to use
their inhaled medications as usual and record the date and time they administered
their medication over a one-week period. Moderate correlations (rs = .55, Mdnd =
95.8, Mdnc = 91.6) were found when comparing the number of administrations
calculated using the MDI Chronolog to the number of administrations reported in
the subject's diary. When the dosing interval was examined, however, the
correlation was weaker (rs = .44, Mdndiary = 92.8, Mdnchronolog = 37.5). In each
case, self-reported compliance was higher than monitored adherence.
PMID- 9755351
TI - Effects of preparatory videotapes on self-efficacy beliefs and recovery from
coronary bypass surgery.
AB - This study evaluated the relative effects of three experimental videotapes that
involved different approaches for preparing coronary artery bypass graft (CABG)
patients for surgery and the inhospital recovery period. One of the tapes
conveyed information via a health care expert only. The other two featured the
same health care expert and also included clips of interviews with patient
models. These latter two tapes differed in the extent to which they portrayed the
recovery period as a steady, forward progression or as consisting of "ups and
downs". Two hundred fifty-eight male CABG patients were randomly assigned to view
one of the three videotapes on the evening prior to surgery or to a control
condition. Overall, patients who viewed any of the videotapes felt significantly
better prepared for the recovery period, reported higher self-efficacy for using
the incentive spirometer and for speeding their recovery, performed more
repetitions with their incentive spirometer each time they used it
postoperatively, had shorter intensive care unit stays, and were released from
the hospital more quickly than patients in the control condition. There was also
evidence that patients' self-efficacy beliefs for speeding recovery directly
mediated the effects of the videotapes on length of stay both in the intensive
care unit and in the hospital.
PMID- 9755352
TI - Serotonin: how much we have learned! So much to discover...
PMID- 9755353
TI - Possible serotonergic mechanisms underlying the antidepressant and anti-obsessive
compulsive disorder responses.
AB - Considerable evidence is now available to support the pivotal role of the
serotonin (5-HT) system is exerting the antidepressant response in humans.
Different type of antidepressant treatments enhance 5-HT neurotransmission via
different pre- or postsynaptic mechanisms. The time course for the occurrence of
these adaptive changes in the brain of laboratory animals is consistent with the
delayed onset of the antidepressant response in humans. The drugs effective in
obsessive-compulsive disorder (OCD) also enhance 5-HT neurotransmission in brain
regions involved in mediating OCD symptoms but with a more prolonged delay,
consistently with the larger time necessary to obtain therapeutic effect in OCD
than in depression. The elucidation of these mechanisms of action lead to the
development of new pharmacologic strategies to potentiate the therapeutic effect
of the drugs currently available and the identification of novel targets to
accelerate and further improve treatment response in depression and OCD.
PMID- 9755354
TI - Novel therapeutic approaches beyond the serotonin receptor.
AB - The influence of serotonin (5-HT) on neuronal function is mediated by regulation
of receptor-coupled intracellular signal transduction pathways, and the
therapeutic action of 5-HT selective reuptake inhibitors (SSRIs), as well as
other types of antidepressants, most likely involves regulation of these
intracellular pathways. The cyclic adenosine monophosphate (cAMP) second
messenger system is one pathway that could be involved in antidepressant action.
Chronic administration of antidepressants, including SSRIs, up-regulates the cAMP
pathway at several levels, including increased expression of the cAMP response
element binding protein (CREB). Among the multiple target genes that could be
regulated by CREB and that could be involved in antidepressant actions and the
pathophysiology of depression in brain-derived neurotrophic factor (BDNF). Stress
decreases the expression of BDNF, and reduce levels of this neurotrophic factor
could contribute to the atrophy and decreased function of stress-vulnerable
hippocampal neurons. In contrast, antidepressant treatment increases the
expression of BDNF in hippocampus, and could thereby reverse the stress-induced
atrophy of neurons or protect these neurons from further damage. Up-regulation of
the cAMP and BDNF systems has resulted in a novel model for the mechanism of
action of antidepressants and new targets for the development of therapeutic
agents.
PMID- 9755355
TI - Child and adolescent mood disorders--experience with serotonin-based therapies.
AB - By most measures, child and adolescent depression is much like and continuous
with adult depression. Aggregating all available data, much of which is
relatively new, it seems most likely that noradrenergic and mixed
serotonergic/noradrenergic tricyclic antidepressants are ineffective in child and
adolescent depression, whereas serotonergic antidepressants (e.g., selective
serotonin reuptake inhibitors) are probably effective).
PMID- 9755356
TI - Serotonergic synergism: the risks and benefits of combining the selective
serotonin reuptake inhibitors with other serotonergic drugs.
AB - It has become common clinical practice to combine the selective serotonin
reuptake inhibitors with other serotonergic agents for augmentation or adjunctive
purposes. The empirical basis for using these combinations remains limited, but
is growing. Also growing is a literature that suggests that even the most
apparently benign combinations of serotonergic drugs carry at least some risk of
serious pharmacokinetic or pharmacodynamic drug interactions, such as a serotonin
syndrome.
PMID- 9755357
TI - Implications of failing to achieve successful long-term maintenance treatment of
recurrent unipolar major depression.
AB - This is a review article that describes current data, issues, and controversies
regarding long-term maintenance treatment of depression. The authors suggest that
the issues represent a public health crisis. This paper will identify the need,
from both a health-care and economic perspective, for more research on the
efficacy of maintenance treatment for this pernicious and lifelong disorder. Data
will be reviewed on the natural course of unipolar depression, focusing on
clinical predictors that increase the risk of a relapse or recurrence. This
review will include new data from the National Institute of Mental Health
Collaborative Depression Study. Failing to achieve adequate maintenance treatment
for unipolar recurrent major depression has psychopathological and psychosocial
consequences, decreasing work productivity and the quality of a person's life.
Published double-blind placebo-controlled studies on continuation treatment of
major depression will be reviewed. The two competed double-blind placebo
controlled long-term maintenance studies of recurrent unipolar major depression
will be discussed in detail. Despite the positive findings from research done to
date, there remain many unresolved questions relating to the maintenance
treatment of recurrent unipolar major depression, and the need for research in
this area is critical. The paper concludes with recommendations for long-term
maintenance treatment of unipolar major depression.
PMID- 9755358
TI - MN blood groups and bipolar disorder: evidence of genotypic association and Hardy
Weinberg disequilibrium.
AB - BACKGROUND: MN blood groups have been studied in the past as a genetic marker of
biopolar disorder (BD). Several previous studies reported an association of the
illness with lower frequency of blood group NN. METHODS: We analyzed distribution
of MN blood groups in a sample of 174 patients with BD, 176 with unipolar
depression, 98 with schizophrenia, and 331 healthy controls. In addition, we
tested whether the inferred genotypes. conform to Hardy-Weinberg equilibrium
(HWE). RESULTS: The frequency of NN phenotype was significantly lower among the
bipolar patients than in any of the other three groups (p < .001). The genotype
frequencies in the BD group deviated significantly from those expected under HWE
(p < .01). CONCLUSIONS: These results suggest a possible locus on chromosome 4
(4q28-q31.1) associated with genetic susceptibility to bipolar illness.
PMID- 9755359
TI - The role of the beta-noradrenergic system in cholecystokinin-tetrapeptide-induced
panic symptoms.
AB - BACKGROUND: The authors determined whether effective beta-adrenergic blockade
could attenuate the panicogenic effects of cholecystokinin-tetrapeptide (CCK-4)
in healthy volunteers. METHODS: Subjects were randomly assigned to either a
propranolol (n = 14) or placebo (n = 16) infusion. Ten minutes after completion
of the infusion subjects received a bolus injection of CCK-4 (50 micrograms).
RESULTS: Acute pretreatment with propranolol was more effective than placebo in
decreasing behavioral and cardiovascular sensitivity. CONCLUSIONS: These
preliminary results suggest that the panicogenic effects of CCK-4 are mediated,
in part, through the beta-adrenergic system.
PMID- 9755360
TI - Effects of meta-chlorophenylpiperazine on cerebral blood flow in obsessive
compulsive disorder and controls.
AB - BACKGROUND: A number of studies have shown that the serotonin receptor agonist
meta-chlorophenylpiperazine (mCPP) can exacerbate symptoms in patients with
obsessive-compulsive disorder (OCD). The aim of the present study was to study
the effect of this compound on regional cerebral blood flow (rCBF) in patients
and controls. METHODS: Seven OCD patients and 8 healthy controls were randomly
allocated to a double-blind challenge study with mCPP (0.5 mg/kg orally). rCBF
was measured by 99m-Tc-hexamethyl-propyleneamineoxime single photon emission
computed tomography. RESULTS: mCPP did not induce OCD symptoms in patients, but
caused a significant decrease in rCBF in OCD patients, but not in controls. The
decrease was seen in the reference regions cerebellum and whole brain, and in the
frontal cortex, caudate nucleus, putamen, and thalamus. CONCLUSIONS: The effect
of mCPP on the reference regions in patients posed methodological problems in the
normalization methods. A possible role of the cerebellum in OCD is discussed.
PMID- 9755361
TI - No mitochondrial haplotype was found to increase risk for Alzheimer's disease.
AB - BACKGROUND: Seventy Alzheimer's disease (AD) patients and 80 age- and sex-matched
controls were analyzed for mitochondrial mutations T4336C and A3397G, reported to
be associated with AD, and for mutations T4216C/G13708A characteristic for a
normal human haplotype associated with increased frequency of occurrence of some
hereditary diseases. The distribution of apolipoprotein E (apoE) alleles was also
analyzed. METHODS: Mitochondrial DNA was amplified by polymerase chain reaction,
and the presence of mutations was detected by digestion with approximately chosen
restriction endonucleases (restriction fragment length polymorphism). RESULTS:
One patient and 2 controls were found to belong to the T4336C/T1630C haplotype.
No A3397G mutant was detected. The T4216C/G13708A haplotype occurred at 5/70 and
5/80 frequency in the two groups. Prevalence of the apoE4 allele was
significantly higher in AD patients (25%) than in the control group (8.1%).
CONCLUSIONS: The T4336C/T16304C mutations were not found to associated with AD,
and no predisposing mitochondrial haplotypes were found.
PMID- 9755362
TI - Sexual dysfunction and selective serotonin reuptake inhibitors.
PMID- 9755363
TI - Dual relation between leptin and cortisol in humans is disturbed in Alzheimer's
disease.
PMID- 9755366
TI - Performance of healthy adults versus individuals with brain injuries on the
supplemental measures of the WAIS-R NI.
AB - The Wechsler Adult Intelligence Scale-Revised as a Neuropsychological Instrument
(WAIS-R NI) provides methods to uniformly interpret atypical responses or
response patterns. To date, little research has examined the primary population
for which the supplemental measures of the WAIS-R NI were intended. The purpose
of the present study was to compare the performance of individuals with brain
injuries versus healthy adults on the supplemental measures of the WAIS-R NI.
Forty-nine healthy adults and 45 individuals with brain injuries were tested.
MANOVA indicated a significant main effect for group membership and the results
suggest the WAIS-R NI supplemental measures differentiate individuals with brain
injuries from healthy adults.
PMID- 9755365
TI - Depression after traumatic brain injury: conceptualization and treatment
considerations.
AB - The understanding and treatment of depression that develops following traumatic
brain injury (TBI) is still unclear and likely to be the result of a complex
variety of interacting factors. Past researchers have developed ways to classify
important variables related to patients' depression into broad domains such as:
Pre-injury assets and liabilities, the nature and severity of brain injury; and
reaction to difficulties. However, a better conceptualization of the problem is
required in order to guide the assessment and treatment considerations for
depressed patients with TBI. This review provides this conceptualization by
postulating six theoretical relationships between depression and TBI. The degree
of empirical support provided in the literature for these links is indicated.
Research findings suggested that an individual with TBI is the most susceptible
to depression when any of the following conditions exist: a pre-existing
psychiatric disturbance is exacerbated; the injury sustained involved the left
anterior region of the brain; and when her individual has poor insight into her
deficits, attempts to resume her pre-injury roles and experiences significant
failure. For each relationship, a likely outcome is predicted if the recommended
treatment plan is not conducted. The present conceptualization and treatment
considerations will be of substantial benefit to clinicians working in the area.
PMID- 9755364
TI - Blood alcohol level and early cognitive status after traumatic brain injury.
AB - STATEMENT OF PURPOSE: This archival study sought to clarify the relationship
between admission blood alcohol level (BAL) after traumatic brain injury (TBI)
and subsequent neuropsychological functioning. It was hypothesized that BAL would
be positively correlated with impairment on basic neuropsychological tests and
that this relation would weaken as time since TBI increased. METHODS: Fifty-eight
patients were tested within 60 days of their TBI. Correlational analyses were
used to test the relation between neuropsychological performance and admission
BAL. RESULTS: As expected, BAL was unrelated to demographic variables or lag time
between TBI and time of testing, Bivariate correlations showed that higher BAL
predicted poorer performance on a broad range of neuropsychological tests.
Patients tested less than 30 days after their TBI showed the strongest effects.
CONCLUSIONS: Neuropsychological impairments detected 1-2 months after TBI may be
affected by BAL at the time of hospital admission. The influence of BAL seems
greatest during the first month post-injury, but may persist beyond 30 days in
some areas of cognitive function. Blood alcohol at the time of injury may have a
direct effect on cognitive functioning or may be a proxy for the effects of
chronic alcohol use or abuse. Clinical implications are discussed.
PMID- 9755367
TI - Spontaneous complaints of long-term traumatic brain injured subjects and their
close relatives.
AB - Long-term consequences of head injury for patients and families are not well
known, given the complexity of variables that have to be studied. Subject's self
experience is one of these less studied aspects. The purpose of this study is to
examine the spontaneous complaints of long-term brain injured adult subjects to
be compared to the impression of their relatives. A total of 48 chronic head
trauma subjects were studied more than 6 years after injury together with a
relative, usually a mother or wife. At the beginning of the interview the
participants were asked to freely refer their present complaints. In general,
relatives referred more complaints about the injured subjects than the injured
subjects referred about themselves. This occurred in several domains: somatic,
physical, cognitive, and behavioural. Memory problems were highly reported by
both groups. Somatic complaints were more frequently reported by patients and
behavioural problems were more often reported by relatives. Mothers and wives had
different profiles or responses. Mothers' opinions were identical to those of
their TBI sons in all domains. These different results must be taken into
consideration so that the real needs of patients and relatives can be addressed.
PMID- 9755368
TI - Competence in discourse as a measure of social integration and quality of life in
persons with traumatic brain injury.
AB - Persisting difficulties in communication are a serious handicap faced by many
after traumatic brain injury (TBI) and a major barrier to community
reintegration. Conventional approaches to the study of communication problems
after TBI have focused on the form of language production and expression, usually
in terms of phonological, semantic, and syntactical features. Most TBI patients,
however, perform overall within normal ranges on these conventional indicators.
More recently, attention has focused on language in its naturally-occurring form,
that is, discourse, which is heavily influenced by linguistic, cognitive and
social skills. Because most TBI patients are left with residual deficits in these
areas, study of discourse abilities seem to be particularly suited to
understanding their problems in communication and facilitating eventual
reintegration into the community. This study was designed to determine if and how
the conversational discourse of TBI patients differs from a matched non-TBI group
and whether any identified variables are related to measures of outcome as
measured by community integration and quality of life. Additionally, the study
was designed to explore the relationship between TBI and features of discourse
across conversational, narrative, procedural genres. TBI patients (n = 30) from
an out-patient brain injury programme were compared to matched controls (n = 10)
in the three discourse genres. Bivariate and multivariate analyses evaluated 23
measures of discourse efficiency, complexity, topic management, information and
pragmatic behaviours in each genre as well as measures of psychosocial
adjustment, particularly social integration and quality of life. Results
indicated that TBIs were significantly different from controls on several
measures of discourse and psychosocial adjustment. A number of other features of
discourse were found to correlate significantly with social integration and
quality of life. Interestingly, discourse variables appeared to correlate with
social integration more strongly than age, gender, education, and other
conventional psychosocial factors. Contrary to prediction, features of
conversational discourse did not correlate more strongly than other types of
discourse with social integration and quality of life. Discussion centred on the
apparent comorbidity of features in everyday discourse and psychosocial
determinants that were associated with quality of life and social integration.
PMID- 9755369
TI - Effects of mild traumatic brain injury on narrative discourse production.
AB - Mild traumatic brain injury (MTBI) and postconcussive syndrome can result in
difficult to document complaints regarding subtle language use. Narrative
discourse production has been shown to be a sensitive index of linguistic and
cognitive deficits in the more severe TBI population. The narrative discourse
production of MTBI subjects was investigated to determine whether cognitive
changes were reflected in linguistic production. Eight MTBI, five moderate TBI,
and five neurologically normal subjects were matched for age, education, and
gender. The TBI subjects were matched on a number of neuropsychological measures.
The subjects produced narratives about their correct picture sequences on five
items from the Wechsler Adult Intelligence Scale-Revised picture arrangement
subtest. The narratives were scored for correct arrangement, content essential
information, correct story, and implied meaning. Significant differences were
found between the normal control group and both the TBI groups on accuracy of
narrative description of the correct picture sequences. Although differences in
generation of implied meaning failed to reach significance, a trend was noted for
both the TBI groups to produce fewer implied meanings than the control group. The
results suggest that cognitive disruptions associated with MTBI may affect the
quality of narrative discourse.
PMID- 9755370
TI - Auditory vs visual speech timing cues as external rate control to enhance verbal
intelligibility in mixed spastic-ataxic dysarthric speakers: a pilot study.
AB - Metronome, singing, and board pacing were used as external rate control
techniques for the purpose of comparing the effectiveness of auditory and visual
speech timing cues for reducing speech rate and increasing intelligibility in
three traumatically brain injured mixed spastic-ataxic dysarthric speakers. A
single system design with baseline reversal (ABACAD) was used in this preliminary
investigation. Results demonstrated statistically significant (p < 0.05) changes
in increased speech intelligibility during all three pacing conditions for the
two more involved subjects. Differences between treatment conditions were not
statistically significant. However, auditory metronome cuing showed the best
results for the two subjects who benefited from rate control. Lower baseline
intelligibility was strongly correlated with higher benefit from rate control.
Furthermore, the two auditory rhythmic pacing conditions exhibited a close
synthronization effect between the frequency rate of the cue and speech rate.
Significant correlation coefficients between decreased speech rate and increased
intelligibility were only found for the two more involved subjects. These
findings suggested a differential benefit of slowing speech rate to improve
intelligibility contingent upon severity of speech deficits.
PMID- 9755371
TI - Female TBI patients recover better than males.
AB - The purpose of the present study was to look at possible gender differences in
outcome after severe traumatic brain injury. Three hundred and thirty four
consecutive patients, 72 females and 262 males, age range 5-65 years, were
included in the study. Age range and severity of injury, evaluated by duration of
unconsciousness, did not differ between male and female patients. Predicted
outcome at the time of discharge from an in-patient rehabilitation programme was
evaluated according to work capacity. Female TBI patients had a better predicted
outcome (p < 0.015). It is suggested that progesterone, acting as a
neuroprotective agent, may explain this difference in outcome.
PMID- 9755372
TI - The snail companies. Neurex Corporation & Cognetix Inc.
PMID- 9755373
TI - Show me the money.
PMID- 9755374
TI - [10 years of Fraxiparin. Milestones in the prophylaxis of thromboembolism].
PMID- 9755376
TI - Meaningful quotations from Paul Dudley White.
PMID- 9755375
TI - Viagra, the latest cardio-VASCULAR drug.
PMID- 9755377
TI - Potential cardiovascular applications of glutamate, aspartate, and other amino
acids.
AB - Cardioplegic solutions rich in the hydrophilic, basic amino acids, glutamate and
aspartate, have enhanced myocardial preservation and left ventricular function.
This has been demonstrated in assorted animal preparations involving ischemia
with and without reperfusion. Published clinical data, though limited, strongly
support the contention that these amino acids have myocardial protective
properties. Several biochemical mechanisms exist by which certain amino acids may
attenuate ischemic or reperfusion injury. Glutamate and aspartate may become
preferred myocardial fuels in the setting of ischemia. They may also reduce
myocardial ammonia production and reduce cytoplasmic lactate levels, thereby
deinhibiting glycolysis. Some amino acids may become substrate for the citric
acid cycle. Glutamate and aspartate also move reducing equivalents from cytoplasm
to mitochondria where they are necessary for oxidative phosphorylation and energy
generation. A rationale exists for the use of an amino acid-rich cardioplegia
like solution in myocardial infarction. These solutions are safe and inexpensive.
PMID- 9755378
TI - Acute ischemic syndromes following coronary artery bypass graft surgery.
AB - Coronary artery bypass graft (CABG) surgery, performed for the control of angina
pectoris, leads to postoperative relief from symptoms in most patients.
Amelioration of ischemia and improvement in exercise capacity after CABG are well
documented. However, patients currently undergoing CABG are more complex than in
the past--they are older and are maintained on medical therapy for longer
periods. A large number of these patients have had one or more previous
myocardial revascularization procedures. The post-operative period would appear
to be a time of vulnerability for coronary events. However, previous
investigators have focused on the pre- and intraoperative aspects of peri-CABG
ischemia. Outcome data suggest that the postoperative interval is at least
equally important as a determinant of short- and long-term morbidity and
mortality. We discuss the epidemiology, etiology, pathophysiology, and treatment
of ischemic syndromes in the postoperative period after CABG. In addition, we
review recent data from a series of 14 patients, observed at our institution, who
underwent cardiac catheterization and, in some cases, angioplasty of the culprit
vessel in the immediate postoperative period.
PMID- 9755379
TI - Verapamil use in patients with cardiovascular disease: an overview of randomized
trials.
AB - BACKGROUND: Several reports have questioned the lack of safety data on calcium
antagonists as a drug class. Because this drug class is heterogeneous, unique
features of certain calcium antagonists may set them apart in terms of safety and
efficacy. HYPOTHESIS: With in excess of 7,000 person-years of observation from
randomized clinical trials, verapamil was selected to evaluate whether there was
evidence of harm in patients with cardiovascular disease. METHODS: MEDLINE search
of English-language articles, Science Citation Index, Current Contents, manual
review of cited references, pharmaceutical files, and investigator correspondence
was performed. Independent review of 66 articles identified 14 randomized,
parallel-group studies for inclusion. Independent, duplicate assessments were
made of patient outcomes and trial characteristics (including study design,
treatment dosage and schedule, duration of treatment, inclusion criteria, and
sample size). Standard meta-analytic techniques were employed for analysis and
interpretation of results. RESULTS: Based on over 4,000 person-years of
observation, patients with acute myocardial infarction (MI) treated with
verapamil had a decreased risk of nonfatal reinfarction compared with placebo
(relative risk 0.79; 2-sided 95% confidence interval 0.65.0.97; p = 0.024).
Verapamil had no significant effect on overall mortality compared with placebo
(relative risk ranged from 0.93; 2-sided 95% confidence interval 0.78, 1.10; p =
0.40 to 0.86; 2-sided 95% confidence interval 0.71, 1.04; p = 0.13) depending on
rules used to include or exclude patients from the pooling process. For the
combined outcome of death or reinfarction, verapamil use was associated with a
decreased risk compared with placebo (relative risk 0.82; 2-sided 95% confidence
interval 0.70, 0.97; p = 0.016). In patients with angina involving a wide
spectrum of disease severity, data were limited to 2,900 person-years of
observation, and verapamil use did not appear to be associated with an apparent
effect on mortality or MI. Data available from randomized studies of verapamil in
patients with hypertension were too limited to reach conclusions (50 person-years
of observation, with no deaths or MIs reported). Subgroups of hypertensive
patients in two of the largest post-MI studies and the largest angina study,
involving over 600 patients, yielded little useful added information.
CONCLUSIONS: In patients with MI, the risks of both nonfatal reinfarction and the
combined outcome of death or nonfatal MI were reduced over intermediate-term
follow-up among patients treated with verapamil compared with controls (p = 0.024
and p = 0.016, respectively). In patients with angina, no evidence for harm was
noted, but in hypertension the data were too limited to draw conclusions. These
findings support the need to distinguish among different calcium antagonist
compounds and to emphasize the need for more data in patients with hypertension.
PMID- 9755381
TI - Maximizing the hemodynamic benefit of enhanced external counterpulsation.
AB - BACKGROUND: Enhanced external counterpulsation (EECP) has been demonstrated to be
an effective treatment for angina and exertional ischemia in patients with
coronary disease. HYPOTHESIS: It is hypothesized that the ability of EECP to
enhance the recruitment or development of coronary collaterals in coronary artery
disease may be determined by the relative magnitude of diastolic augmentation
(DA) and systolic unloading (SU). This study examines the relation between the
proposed EECP effectiveness ratio (DA/SU), as assessed by finger plethysmography,
and changes in descending aortic flow as assessed by Doppler echocardiography in
15 patients during EECP. METHODS: Varying external cuff pressures (0-275 mmHg)
were used to generate a range of DA/SU ratios. The effect on aortic antegrade
systolic and retrograde diastolic flow was assessed by Doppler echocardiography
to determine whether there was an optimal EECP effectiveness ratio that maximizes
the hemodynamic effects of EECP. With increasing DA/SU there was an initial
positive linear increase in both systolic and diastolic flow volume. Systolic
flow maximized at an effectiveness ratio of 1.5 and diastolic flow at a ratio of
2.0 RESULT: Therefore, effectiveness ratios (DA/SU) in the range of 1.5-2.0 are
optimal for maximizing the hemodynamic effects of EECP.
PMID- 9755380
TI - A comparative study of eccentric and concentric coronary stenosis vasomotion in
patients with Prinzmental's variant angina and patients with stable angina
pectoris.
AB - BACKGROUND AND HYPOTHESIS: In patients with stable angina pectoris, eccentric
stenoses have a greater potential for dynamic changes of caliber in response to
vasoactive stimuli than concentric lesions. It is not known whether in patients
with coronary artery spasm the degree of coronary vasoconstriction differs in
eccentric versus concentric stenoses. Therefore, we examined the relationship
between coronary stenosis morphology and the vasomotor response to vasoactive
stimuli in patients with variant angina. METHODS: Computerized quantitative
angiography was used to measure minimum luminal diameter of eccentric and
concentric stenoses before and after the administration of ergonovine and
isosorbide dinitrate in 22 patients with Prinzmetal's variant angina and in 20
patients with chronic stable angina. RESULTS: In patients with variant angina,
mean stenosis diameter reduction with ergonovine was -0.85 +/- 0.38 and -1.12 +/-
0.69 mm in eccentric and concentric stenoses, respectively (p = NS). Isosorbide
dinitrate promptly relieved spasm in all patients and increased the diameter of
eccentric stenoses by 0.26 +/- 0.34 mm and that of concentric stenoses by 0.24 +/
0.32 mm (p = NS). In patients with chronic stable angina, mean diameter
reduction with ergonovine was -0.23 +/- 0.12 and -0.12 +/- 0.10 mm for eccentric
and concentric stenoses, respectively (p < 0.05). Isosorbide dinitrate increased
coronary diameter by 10% from baseline in 70% of eccentric and 38% of concentric
stenoses (p < 0.01). CONCLUSION: In patients with variant angina pectoris,
eccentric and concentric spastic stenoses react similarly in response to
vasoactive stimuli. In patients with chronic stable angina, eccentric stenoses
are more likely to show vasomotor responses than concentric stenoses.
PMID- 9755382
TI - Serum amyloid type A may be a predictor of restenosis.
AB - BACKGROUND: Elevation of acute phase proteins [C-reactive protein (CRP) and serum
amyloid type A (SAA)] has been demonstrated in unstable angina with an adverse
clinical prognosis. HYPOTHESIS: The study was undertaken to determine the effect
of angioplasty on the levels of SAA and the correlation with postangioplasty
restenosis. METHODS: In a university-affiliated tertiary medical center, a
prospective case study was undertaken in 55 patients who underwent successful
percutaneous transluminal coronary angioplasty (PTCA) of a single coronary lesion
for angina pectoris. Three groups of patients were clinically characterized
according to Braunwald's classification of anginal syndrome: Group A: class III;
Group B: class I; Group C: stable angina. Serum amyloid type A was measured by an
ELISA method before PTCA and after 24 h, 1, and 3 months. Patients were followed
clinically for 12 months. A thallium stress perfusion scan was performed 3 months
after PTCA and coronary angiography was repeated in patients with an abnormal
thallium perfusion scan. RESULTS: Serum amyloid type A levels > 100 micrograms/ml
could identify Group A patients with a high sensitivity and specificity (r = 0.85
and 0.86, respectively). Of the patients studied, 75% increased their SAA level
24 h after angioplasty. An increase of SAA by > 100% was associated with an
increased risk of restenosis, with a relative risk of 6.4 (p < 0.05). CONCLUSION:
Increased levels of SAA characterize patients with unstable angina pectoris with
a high specificity and sensitivity. Levels of SAA that increase > 100% 24 h after
angioplasty may serve as a marker of restenosis.
PMID- 9755383
TI - Treatment of severe mitral stenosis with percutaneous balloon valvotomy in
pregnant patients.
AB - BACKGROUND: Pregnancy can cause life-threatening complications in women with
mitral stenosis. Frequently, there is an urgent need to increase the mitral valve
area mechanically. In selected cases, percutaneous mitral balloon valvotomy
(PMBV) has emerged as a safe and effective alternative to surgical
commissurotomy. HYPOTHESIS: The study evaluates the effects of PMBV by the Inoue
technique in nine pregnant patients with severe symptomatic mitral stenosis.
METHODS: The patients were in New York Heart Association (NYHA) functional class
II to IV and had echocardiographic scores of < or = 8. The mean gestational age
was 24.8 +/- 6.1 weeks. The patient's pelvic and abdominal regions were covered
with a lead apron to protect the fetus from radiation. A stepwise dilatation
technique was used. Fluoroscopy time was kept to 10 to 15 min. RESULTS: One
patient developed severe mitral regurgitation requiring emergency valve
replacement. The remaining eight patients showed marked immediate symptomatic and
hemodynamic improvement. After dilatation, the transmitral pressure gradient
decreased from 20.8 +/- 6.5 to 7.3 +/- 1.4 mmHg (p = 0.001) and the calculated
mitral valve area increased from 0.9 +/- 0.1 to 1.8 +/- 0.4 (p < 0.001). All
patients had uneventful term deliveries of normal babies. On follow-up they were
in NYHA functional class I. CONCLUSIONS: Percutaneous mitral balloon valvotomy is
a safe and effective procedure for selected pregnant patients with severe mitral
stenosis. The procedure is well tolerated by the fetus. Severe mitral
regurgitation requiring immediate surgery may occur occasionally. The possible
harmful effects to the fetus from its exposure to radiation during PMBV are
unknown.
PMID- 9755384
TI - Comparison of epirubicin and doxorubicin cardiotoxicity induced by low doses:
evolution of the diastolic and systolic parameters studied by radionuclide
angiography.
AB - BACKGROUND: Previous studies have demonstrated that epirubicin (EPI) has a lower
propensity to produce cardiotoxic effects than doxorubicin (DXR) at high doses.
HYPOTHESIS: The aim of the study was to compare the cardiotoxicity induced by low
doses of EPI and DXR in patients before and 1 month after the end of
chemotherapy. METHOD: In a prospective study, 99 patients with a mean age of 51
+/- 12 years and without cardiac disease were studied before and 1 month after
the end of chemotherapy. Group 1 included 38 patients receiving 246 +/- 96 mg/m2
of DXR and Group 2 included 61 patients receiving EPI with and equivalent dose of
219 +/- 92 mg/m2 of DXR. Ejection fraction (EF) of the left ventricle (LV), peak
ejection rate (PER), and peak filling rate (PFR) [expressed in end-diastolic
volume/s (EDV/s)] were evaluated by gated radionuclide angiography; PFR/PER were
also calculated. RESULTS: Moderate and similar alterations of left ventricular
ejection fraction were shown for low doses of anthracyclines. The EF of the LV
decreased from 57 +/- 6% to 54 +/- 6% for DXR group (Group 1) (p = 0.005), and
from 58 +/- 5% to 55 +/- 5% for the EPI group (Group 2)(p = 0.001). The PER of
the left ventricle fell from 3.08 +/- 0.46 EDV/s to 2.79 +/- 0.49 in Group 1 (p =
0.004) and from 2.98 +/- 0.50 to 2.73 +/- 0.34 EDV/s in Group 2 (p = 0.001). In
contrast, no significant alteration of PFR appeared in Group 2 (from 2.72 +/-
0.51 to 2.62 +/- 0.41 EDV/s) for the equivalent dose of anthracycline, while PFR
of the LV dropped from 2.82 +/- 0.76 (EDV/s) to 2.41 +/- 0.55 after doxorubicin
(p = 0.004). No difference was found between 1 and 12 months after the end of the
treatment in 25 patients in Group 1 and 28 patients in Group 2. These results
confirm the advantage of EPI over DXR in terms of cardiotoxicity and help explain
the relationship of cellular damage mechanisms with the functional parameters of
nuclear investigation. CONCLUSION: A possible explanation for specific alteration
after DXR could be the increased production of semiquinone free radicals, which
are known to induce membrane damage and, consequently, myocardial edema and
diastolic alteration.
PMID- 9755385
TI - Symmetric and asymmetric left ventricular hypertrophy in patients with end-stage
renal failure on long-term hemodialysis.
AB - BACKGROUND: Patients with end-stage renal disease on regular hemodialysis have an
increased prevalence of left ventricular (LV) hypertrophy that is associated with
morbidity and mortality. Asymmetric septal hypertrophy and impairment of LV
outflow can occur in these patients and may contribute to adverse outcomes. More
insight into the prevalence, extent, geometry, and promoting factors of LV
hypertrophy is important. METHODS: An unselected group of 62 patients (31 women),
aged 55 +/- 14 years, on maintenance hemodialysis was investigated by Doppler
echocardiography. Eight patients with valvular heart disease were excluded from
further analysis. We assessed prevalence of LV hypertrophy and asymmetric septal
hypertrophy, as well as parameters of LV geometry and LV filling and outflow
dynamics. RESULTS: Prevalence of LV hypertrophy was 65%. Patients were analyzed
according to LV mass and geometry. Mean LV mass index was normal (105 +/- 17
g/m2) in Group 1 without LV hypertrophy (n = 19); it was markedly elevated in
Group 2 (symmetric hypertrophy, n = 22) and Group 3 (asymmetric hypertrophy with
systolic anterior movement of mitral valve, n = 7), and highest (191 +/- 54 g/m2)
in Group 4 (asymmetric hypertrophy without systolic anterior movement of mitral
valve, n = 6, p < 0.001). Age, body mass index, and duration of hypertension were
associated with LV hypertrophy and asymmetric septal hypertrophy (p = 0.01).
Group 3 with systolic anterior motion of mitral valve had the smallest end
diastolic LV diameters (p = 0.02); increased heart rates, and increased ejection
velocities in the LV outflow tract (p = 0.03, and p = 0.005, respectively, vs.
Groups 1, 2, and 4) which pointed to an impairment of LV outflow. CONCLUSIONS:
Symmetric LV hypertrophy and asymmetric septal hypertrophy are frequent in
patients on maintenance hemodialysis. Predictors for LV hypertrophy were age and
body mass index, and, particularly for asymmetric septal hypertrophy, age and
hypertension duration. Volume withdrawal during hemodialysis may lead to
symptomatic hypotension due to dynamic obstruction in some patients with severe
asymmetric septal hypertrophy.
PMID- 9755386
TI - Incidence and prognostic value of electrocardiographic abnormalities after heart
transplantation.
AB - BACKGROUND: The improvement of surgical techniques and the use of
immunosuppressive drugs within the past 15 years has made heart transplantation
an increasingly performed procedure and an accepted treatment for end-stage
cardiac failure. HYPOTHESIS: The aim of this study was to describe the changes of
the 12-lead electrocardiogram (ECG) after heart transplantation and to determine
their prognostic value on complications such as rejection or graft coronary
artery disease during follow-up. METHODS: The ECGs of 62 consecutive patients
were analyzed for 5 years at follow-up periods of 1, 2, 3, 6 months and yearly
after transplantation. RESULTS: The most prevalent abnormality was the presence
of complete or incomplete right bundle-branch block (RBBB). New RBBB appeared in
69% (43/62) of the patients, mainly during the first month (21/43). There was no
left bundle-branch block. We detected nine episodes of supraventricular
arrhythmias: one atrial fibrillation, six atrial flutter, one junctional
tachycardia, one orthodromic tachycardia on a Wolff-Parkinson-White syndrome; all
appearing during the first 3 months. Three of the six episodes of atrial flutter
occurred during an episode of acute rejection. There was no relation between RBBB
and the gender and age of recipients and donors, nor with the graft ischemic time
and the pretransplantation hemodynamic values. Right bundle-branch block was not
associated with acute rejection nor with graft coronary artery disease.
CONCLUSION: The ECG abnormalities after heart transplantation have no predictive
value on the long-term evolution. Right bundle-branch block is very frequent and
is not associated with adverse prognosis.
PMID- 9755387
TI - Images in cardiology. Acquired interventricular septal defect.
PMID- 9755388
TI - Acute myocardial infarction in two adolescent males.
AB - Acute myocardial infarction in previously healthy children is rare in the absence
of congenital anomalies. We describe two cases of acute anterior myocardial
infarction in adolescent males with no congenital heart disease, without prior
history of or risk factors for coronary heart disease, and with no history of
drug abuse. These cases illustrate that myocardial infarction in the absence of
systemic illness or coronary anomalies can occur in an adolescent population.
PMID- 9755389
TI - Constrictive pericarditis after coronary artery bypass surgery as a cause of
unexplained dyspnea: a report of five cases.
AB - Constrictive pericarditis after coronary artery bypass grafting (CABG) is rare
and can present as unexplained dyspnea. We report five consecutive cases of post
CABG constrictive pericarditis seen within a period of 17 months at our
institution. All patients presented with heart failure of unknown etiology within
a period of 8-84 months after surgery. During the initial post-CABG period, two
patients had developed postcardiotomy syndrome that was successfully treated with
steroids. They were all assessed noninvasively and invasively. In all patients,
the diagnosis of constriction was initially suspected clinically (symptoms, high
jugular venous pressure with deep "X" and "Y" descents, pericardial knock).
Echocardiography showed transmitral flow typical of constriction in all patients
and hepatic venous flow in two. Two patients showed rapid left ventricular
relaxation. In all patients, hemodynamic assessment showed diastolic equalization
of pressures in all chambers, "W" shape waveform in right atrial pressure, and
"dip and plateau" configuration in right and left ventricular pressure waveforms.
Diagnosis was confirmed surgically in four patients who were subjected to
pericardiectomy-pericardial stripping (three survived, one died). One patient
refused surgery. We conclude that constrictive pericarditis, although rare,
should be suspected in every case of unexplained dyspnea post CABG. It can appear
early or late after surgery, and clinical examination plays an important role in
its early recognition. It requires a full noninvasive and invasive assessment in
case of clinical suspicion.
PMID- 9755390
TI - Obituary: Herbert N. Hultgren.
PMID- 9755391
TI - Atheromatous plaque reflects serum total cholesterol levels: a comparative
morphologic study of endarterectomy coronary atherosclerotic plaques removed from
patients from the southern part of India and Caucasians from Ottawa, Canada.
PMID- 9755392
TI - Correlation of 3D MRI and clinical findings in the patients with sensorineural
hearing loss and/or vertigo.
AB - The aim of the study was to correlate clinical and magnetic resonance imaging
(MRI) (3D CISS and MP-RANGE) findings in patients with sensorineural hearing loss
(SNHL) and/or vertigo. We found a high correlation of MRI and symptoms (17 out of
18 patients, 13 out of 13, respectively) concerning detectability of tumors and
acute labyrinthitis. In the case of labyrinthine fibrosis, the correlation
between clinical and MRI findings was lower. In conclusion, high-resolution MRI
is very suitable in patients with SNHL or vertigo caused by tumors or acute
labyrinthitis.
PMID- 9755393
TI - Neurosarcoidosis presenting as a large suprasellar mass. Magnetic resonance
imaging findings.
AB - We present unusual magnetic resonance imaging (MRI) findings in a case of
neurosarcoidosis. MRI revealed a large solitary suprasellar mass which resembled
a neoplasm. The lesion was isointense and hyperintense on T1-weighted images,
hypointense on T2-weighted images, and intensely homogeneously enhancing. Biopsy
revealed a polymorphous inflammatory lesion with giant cells, which extended from
the hypothalamus, consistent with neurosarcoidosis. The diagnosis of
neurosarcoidosis should be considered in patients presenting with large midline
tumor-like suprasellar mass lesions.
PMID- 9755394
TI - Pituitary gland. Variable signal intensities on MRI. A pictorial essay.
AB - The anterior pituitary gland may exhibit high signal on T1-weighted (T1w) images
and/or low signal on T2-weighted (T2w) images in several normal and pathological
states. High T1w signal may be seen in normal fetuses, neonates, and in pregnant
and postpartum women. It may also occur in Rathke's cleft cyst,
craniopharyngioma, subacute hemorrhage, manganese deposition, melanoma, dermoid,
and lipoma. Low T2w signal may be seen in hemorrhage, calcification, cystic
lesion, hemochromatosis, melanoma, and vascular lesions. These are described and
illustrated.
PMID- 9755395
TI - Small cortical infarcts mimicking metastatic tumors.
AB - Small cortical enhancing lesions mimicking metastases were demonstrated on
contrast imaging in three patients without specific neurologic deficits
corresponding to the lesions. One patient had a long carcinoma. However, all had
cardiac arrhythmias known as major sources of cerebral emboli. Two had early
cerebral infarcts and ischemic heart diseases. The lesions disappeared
spontaneously on follow-up studies. They were subsequently presumed to be small
infarcts. Clinical information and follow-up examinations are important to
differentiate these small cortical lesions from metastases.
PMID- 9755396
TI - High-resolution CT pulmonary findings in adults with Gaucher's disease.
AB - The purpose of this study was to illustrate high-resolution computed tomography
(HRCT) findings in symptomatic adult Gaucher's disease patients. Five adult
patients with Gaucher's disease experienced dyspnea. These patient were first
evaluated by chest X-ray (CXR) followed by HRCT. The chest X-ray on one patient
demonstrated a calcified granuloma. Two patients had interstitial disease only
seen on HRCT, and two patients had a combination of interstitial and alveolar
disease giving a mosaic pattern better illustrated on HRCT. HRCT can be used
following CXR to evaluate lung pathology in symptomatic adult Gaucher's disease
patients.
PMID- 9755397
TI - Breast carcinoma metastatic to the esophagus. CT findings with pathologic
correlation.
AB - The common sites of metastasis from breast carcinoma include local and distant
lymph nodes, lung parenchyma, bone, liver and brain. While less common,
gastrointestinal carcinoma, involving everything from the tip of the tongue to
the rectum, secondary to metastatic breast carcinoma have been reported. Many of
these lesions occur years after treatment of the primary breast cancer and they
can be confused with a second primary. We present a case of breast cancer
metastatic to the esophagus which produced symptoms of progressive dysphagia in a
women thirteen years after mastectomy and radiation therapy for breast cancer.
PMID- 9755398
TI - Cystic fibrosis: spectrum of thoracic and abdominal CT findings in the adult
patient.
AB - Cystic fibrosis (CF) is an autosomal recessive disorder that is characterized by
an abnormality of exocrine gland function. Adult patients represent a rapidly
growing percentage of the CF population. Pulmonary changes are seen in nearly
every case and are the most serious complication of CF. In advanced lung disease,
bronchiectasis, emphysematous bullae, and subpleural blebs can frequently
develop. Although pulmonary disease is the most common cause of death and
morbidity among CF patients, there also can be involvement of other groups,
particularly in adults, which show characteristic signs on CT and spiral CT.
Pancreatic abnormalities are present in 85-90% of CF patients. The degree of
pancreatic involvement varies, ranging form accumulations of mucus in the small
ducts to totally plugged ducts, which can cause atrophy of the exocrine glands
and progressive fibrosis. Pancreatic dysfunction on CT is demonstrated as fatty
replacement and fibrosis of the pancreas. However, there may be scattered foci of
pancreatic calcifications that can be detectable on plain radiographs.
Hepatobiliary involvement follows the same pattern as pancreatic abnormalities.
Bile canaliculi are plugged by mucinous material and when this plugging is of
long duration, biliary cirrhosis with diffuse hepatic nodularity may develop.
Such severe hepatic involvement is see in only about 2-5% of patients, although
minor hepatic alterations, such as diffuse fatty changes, are fairly common.
Hepatobiliary involvement is characterized by hepatic nodularity, compatible with
cirrhosis, splenomegaly, and ascites. Complete obstruction of the ileum by
meconium occurs in approximately 10% of newborns with CF. Intestinal findings on
CT include obstruction, although this is more common in children. These CT signs
should be evaluated carefully in adult patients since they may be suggestive of
CF. Computed tomography offers unique information about organ involvement (other
than pulmonary) that can alter diagnosis and patient management.
PMID- 9755399
TI - Endoscopic ultrasonography for preoperative locoregional staging and assessment
of resectability in gastric cancer.
AB - We performed a prospective study from November 1989 to December 1996 to assess
the accuracy of endoscopic ultrasonography (EUS) in the locoregional staging and
resectability of patients with gastric carcinoma. One hundred and nineteen
patients with gastric cancer who received preoperative assessment by EUS
underwent subsequent surgery. The endosonographic tumor-node-metastasis (TNM)
classification was used for comparison with the histopathologic findings of the
resected specimens. The ability of EUS to accurately predict the T stage (depth
of tumor invasion) and N stage (involvement of lymph node) was 70% and 65%,
respectively. EUS displayed a tendency to overestimate T stage and underestimate
N state. The differentiation of early gastric cancer from advanced gastric cancer
showed a concordance rate of 89% and underestimation rate of 8% and
underestimation rate of 3%. The accuracy of EUS in predicting the stage T1 to T3,
which correspond to D0 resectability (no macroscopic or microscopic tumor
remains), was 91%. In conclusion, these results revealed EUS as a valuable tool
for evaluating the local staging and resectability of gastric cancer. We suggest
that EUS should be introduced in the preoperative assessment of patients with
gastric cancer.
PMID- 9755400
TI - Portal venous aneurysm demonstrated by magnetic resonance imaging.
AB - Portal venous aneurysm is an unusual vascular abnormality. We present this entity
with magnetic resonance imaging (MRI) findings showing characteristic flow
abnormality in two patients. Ultrasound examination revealed hyperechoic
lobulated masses in the portal vein and the duplex Doppler study confirmed the
venous flow patterns of low resistance within the lesion. The literature
regarding this entity and the potential role of MRI are briefly discussed.
PMID- 9755401
TI - Thin-section CT follow-up of metastatic ovarian carcinoma correlation with levels
of CA-125 marker and clinical history.
AB - Second-look laparotomy and CA-125 are the gold standard in follow-up of ovarian
carcinoma. Since no definite role seems established for cross-sectional imaging
in assessment of recurrence we employed thin-section computed tomography (CT),
correlated with CA-125 levels and detailed knowledge of the clinical history as a
follow-up protocol One hundred seventy-seven patients with ovarian carcinoma were
selected because of: (a) pathologically proven remission after first-line
chemotherapy, (b) follow-up by means of thin-section CT every 6 months for the
fist 3 years and every 10 months subsequently, (c) monitoring CA-125 serum levels
every 3 months for the first 3 years and every 6 months subsequently; (d)
pathologic confirmation or clinical and laboratory follow-up after 12 months or
longer for the CT findings. Fifty percent of the patients showed recurrence of
disease. Our protocol yielded 93.2% true positive, dubious findings in 5.6% 1.0%
false negatives, 97.7% true negative, and 2.3% false positive. With a tailored
technique, CT was particularly sensitive in early diagnosis of peritoneal
seeding, even in the absence of ascites or increases in the levels of CA-125.
Repeated administration of contrast medium, water enemas, and repeated scanning
of suspicious volumes with differing scanning parameters were the factors managed
by the radiologist. We conclude that thin-section CT, correlated with CA-125
levels and careful review of the clinical history could represent a valid
alternative to repeated explorative laparotomies in the follow-up of ovarian
carcinomas.
PMID- 9755402
TI - Prevalence and patterns of tendon calcification in patients with
chondrocalcinosis of the knee: radiologic study of 156 patients.
AB - The presence or absence of tendon calcification was studied at six anatomic
sites: Achilles, gastrocnemius, quadriceps, triceps (elbow), triceps long head
(shoulder), and rotator cuff. The morphology of the calcifications was
categorized in 156 patients with chondrocalcinosis in the knee. Achilles tendon,
gastrocnemius, and quadriceps tendon calcifications were most common, ranging
from 21%-25% of our patient population was thin linear bands. Triceps
calcification at the elbow, rotator cuff calcifications, and long head of triceps
tendon calcification were less common.
PMID- 9755403
TI - Auditing surgical outcome: ten years with the Swedish Vascular Registry-
Swedvasc. The Steering Committee of Swedvasc.
PMID- 9755404
TI - Vascular registries as a method for research and quality development.
PMID- 9755405
TI - Auditing surgical outcome. The Swedish experience.
PMID- 9755406
TI - Examples of studies performed within Swedvasc.
PMID- 9755407
TI - Intestinal ischaemia after aortoiliac surgery--a case-control study within the
Swedvasc Registry.
PMID- 9755409
TI - Outcome and influence of age after infrainguinal revascularization in critical
limb ischemia.
PMID- 9755408
TI - Low-molecular weight heparin versus dextran in the prevention of early occlusion
following arterial bypass surgery distal to the groin.
PMID- 9755412
TI - Follicle stimulating hormone and its receptor: future perspectives.
AB - In this report, we review our present effort in the field of molecular
reproductive endocrinology: to identify a small molecular weight follicle
stimulating hormone (FSH) agonistic molecule. To achieve this goal we require a
number of molecular tools. We have cloned and expressed the human gonadotrophin,
FSH and the human FSH receptor and developed a reliable high throughput assay. We
have also proposed a model to explain FSH receptor activation and from that
model, begun to create small molecules predicted to induce FSH signal
transduction without binding to the extracellular domain of the membrane protein.
In this report, we summarize our efforts to date and discuss our future research
efforts in this area.
PMID- 9755411
TI - New approaches to ovarian stimulation.
AB - Suppression of endogenous hormone production by gonadotrophin-releasing hormone
(GnRH) agonists followed by controlled ovarian hyperstimulation (COH) with human
gonadotrophins, especially the so-called 'long protocol' has developed from
second-line into first-line therapy. Due to this attitude premature luteinization
can be safely avoided, enhancing therapeutic efficacy. Recombinant preparations
of human follicle stimulating hormone (FSH) have been proven to be effective
within COH according to the long protocol. The high purity of these compounds may
have clinical advantages. GnRH antagonists could be successfully introduced in
COH protocols. Also, daily injections in the midcycle phase according to the
'Lubeck protocol', as single or only dual administrations around day 9 seem to
abolish any premature LH rises. Due to their different pharmacological mode of
action, based on a classic competitive receptor blockage GnRH antagonists avoid
any flare-up period and allow ovarian stimulation to start within the spontaneous
cycle. Pregnancy rates are comparable to those after long protocol stimulation.
Combination of softer stimulation regimes like clomiphene citrate and low dose
HMG with midcycle administration of GnRH antagonists may be the way to a cheap,
safe and efficient ovarian stimulation. It seems to be high time for modest forms
of ovarian stimulation, lowering burden and risk for our patients.
PMID- 9755413
TI - Developments in human recombinant follicle stimulating hormone technology: are we
going in the right direction?
AB - Recent developments in recombinant DNA technology have enabled the large scale
production of human recombinant follicle stimulating hormone (rFSH); and this
compound has recently been introduced to the market. Understanding of the
structure-function relationship of FSH isohormones is crucial in understanding
discussions on the standardization procedures of gonadotrophin preparations,
potential differences in clinical efficacy of the various gonadotrophin
preparations and in comprehending future developments (long-acting and short
acting forms, and rFSH preparations with altered isohormone profiles).
Differences between immunoreactive and bioactive serum FSH concentrations have
been observed following the administration of rFSH. Accordingly, the isohormone
distribution of rFSH is similar to, but not identical with, natural human FSH.
Issues relevant to daily practice discussed in this review include: the total
absence of urinary contaminants allowing for the safe s.c. administration of the
compound. Production is independent from urine, and the capacity can be adjusted
according to clinical needs. The relationship between serum oestradiol
concentrations and number and size of follicles observed by ultrasound may change
when rFSH is combined with gonadotrophin-releasing hormone (GnRH) agonist, due to
low serum lueinizing hormone (LH) concentrations. In the case of endogenous serum
LH concentrations within the normal range, exogenous administration of LH is
redundant. In the near future, rFSH preparations with altered bioactivity will be
available.
PMID- 9755415
TI - Immature oocyte retrieval combined with in-vitro oocyte maturation.
AB - Immature oocyte retrieval combined with in-vitro oocyte maturation has a
considerable potential to increase knowledge on the microenvironment and nuclear
and cytoplasmic maturation, and may be an alternative or even replacement for
routine in-vitro fertilization as practised today. Understanding the critical
steps to accomplish this task demands ongoing research to produce a comparable
microenvironment to that of the developing follicle. This will allow cytoplasmic
maturation to occur, and clarify knowledge on the selection of the dominant
follicle, and utilize novel aspects fertilization and embryo culture in vitro. A
second aspect of the produce concerns its clinical aspects. These include a
better understanding of the number of antral follicles that can be retrieved
transvaginally and the nature of the endometrial window and its advancement in
order to provide a window of opportunity for implantation to occur.
PMID- 9755414
TI - Oocyte maturation.
AB - Primary oocytes recovered from small and growing follicles of > or = 3 mm in the
ovaries of untreated women, can be matured in vitro, will fertilize and develop
in vitro, and when transferred to the patient, develop to term. However, the
implantation rate of cleaved embryos has been disappointingly low and when
embryos are allowed to develop beyond the 4-cell in vitro, retardation of
development and blockage is frequently observed, with relatively few embryos
developing to blastocysts. We have devised new culture systems for human embryos
to enable high rates of development of in-vivo matured oocytes to blastocysts
within 5-6 days of culture, and high implantation rates of these blastocysts when
they are transferred to the patients' uterus. These culture systems are now being
used for in-vitro matured oocytes. In order to determine whether embryo
developmental competence could be improved, a number of factors were examined.
Treatment of patients with pure follicle stimulating hormone (FSH) early in the
follicular phase, or treatment with oestrogen prior to oocyte recovery, had no
apparent effect on any parameters of oocyte developmental competence. There was
no indication that a medium made specifically for human oocyte maturation
improved oocyte developmental competence. Nuclear and cytoplasmic changes in
oocytes matured in vitro appear to be similar to that in vivo, although some lack
of synchronization in completing maturation is evident. It is possible that
follicles of < 10 mm diameter in the human contain developmentally-incompetent
oocytes. However, the development to term and birth of normal babies from
germinal vesicle stage oocytes recovered from small follicles and matured in
vitro, suggests that further research will identify the factors necessary to
improve embryo developmental competence. The application of immature oocyte
collection (IOC) and in vitro maturation (IVM) as an alternative to ovulation
stimulation with high doses of gonadotrophins for in-vitro fertilization (IVF),
remains a priority for research in human medicine.
PMID- 9755416
TI - Genetic contribution to male infertility.
AB - Worldwide, of couples trying for a child, 2-7% fail to conceive. Extensive
screening programmes of men attending infertility clinics show that chromosomal
and gene disorders make a significant contribution to spermatogenic impairment.
It appears that an orderly genome is essential for normal germ cell development,
since numerical and structural chromosome abnormalities are found in association
with germ cell breakdown. The most recent research indicates that genes on the Y
chromosome and autosomes are involved in spermatogenic control.
PMID- 9755417
TI - Spermatids as gametes: indications and limitations.
AB - The feasibility of achieving viable embryos, developing to term after transfer
into the uterus, by fertilizing oocytes with spermatids has been demonstrated
both in animal studies and in preliminary human clinical trials. Here we review
the current clinical indications of spermatid conception and discuss the
predictable success rates associated with each of these indications. Potential
health hazards relating to the use of spermatids for conception are updated
taking into account the risk of abnormal or incomplete epigenetic modifications
of newly discovered human imprinted genes. We also add new experimental data
showing the occurrence of spermatids in patients lacking spermatozoa and
demonstrating that round spermatids recovered from patients with complete
spermiogenesis failure (no elongated spermatids or spermatozoa ever detected in
the patient's history) are often deficient in the factor(s) responsible for
oocyte activation. The possible consequences of this deficiency for the
occurrence of abnormal fertilization patterns and for the impairment of further
preimplantation and post-implantation development are discussed. It is concluded
that the development of diagnostic tests to assess the intrinsic quality of
spermatids, with regard to their ability to act as gametes, is urgently needed as
part of pre-treatment diagnosis before infertile couples are included in a
spermatid conception programme. Centres wishing to use spermatids in human
assisted reproduction should also be prepared to offer adequate diagnostic
methods to control genomic imprinting abnormalities in the progeny.
PMID- 9755418
TI - Clinical application of new micromanipulative technologies to treat the male.
AB - Traditional treatments of the male have produced no improvement in sperm
parameters. Since the rate of normal fertilization rate is significantly lower in
these cases after classic in-vitro fertilization (IVF), intracytoplasmic sperm
injection (ICSI) has become the preferred method of treatment. It has been
successfully applied in cases of extreme oligoasthenoteratozoospermia, and
obstructive and non-obstructive azoospermia. Cryopreservation of testicular
tissue will replace the repeated use of fresh testicular tissue. Full information
has to be provided to patients about the frequency (approximately 3%) of sex
chromosome and autosomal aberrations in men with extreme
oligoasthenoteratospermia. The need for screening for Yq deletions is still under
study, and any therapeutic consequences for the newborn child will have to be
analysed. The incidence of major malformations in newborn children is
approximately 2.5%, i.e. comparable with that of the general population.
Screening for de-novo sex chromosome aberrations may be particularly useful for
men with sperm counts of < 5 x 10(6) and those with non-obstructive azoospermia.
PMID- 9755419
TI - New approaches to achieving human fertilization: a resume.
PMID- 9755420
TI - Culture and quality control of embryos.
AB - Improvement of embryo quality during in-vitro culture can be achieved by
understanding and controlling the requirements of gametes and embryos. The most
obvious route is to alter culture media, but standardization could be influenced
by diverse environmental factors. Abnormal embryos from patients with multiple
failures probably do not benefit from standardization and require specialized
therapy, that is if their physiology is not already irreversibly jeopardized
during gametogenesis. This paper describes the adverse environmental factors
present in laboratory air and released by common products used by laboratories.
Assays and results of the air determinations in several laboratories are
reported, as well as potential counter measures. The possibility of altering the
immediate environment of the nucleus of the egg by ooplasmic transplantation is
also considered, and the first attempts resulting in two ongoing pregnancies are
reported.
PMID- 9755421
TI - Culture of viable human blastocysts in defined sequential serum-free media.
AB - In human in-vitro fertilization (IVF), embryos are routinely transferred to the
uterus on either day 2 or day 3 of development, resulting in a 10-15%
implantation rate. However, in other mammalian species, the transfer of cleavage
stage embryos, which normally reside in the oviduct, to the uterus results in a
significantly lower implantation rate compared with blastocysts. It is therefore
proposed that, in order to increase implantation rates in human IVF, one has to
move to extended culture and transfer at the blastocyst stage. The transfer of
blastocysts will not only help synchronize the embryo with the female tract but
will facilitate the identification of those embryos with little or no
developmental potential. In order to culture viable blastocysts it is important
to use more than one culture medium to cater for the changing requirements of the
preimplantation embryo as it develops and differentiates. If sequential culture
media are not used, one can obtain blastocysts but their resultant viability is
low. The use of sequential serum-free media in human IVF has resulted in > 50% of
embryos becoming blastocysts with an implantation rate of approximately 50%.
Further advances in human embryo culture should come from the replacement of
protein with the glycosaminoglycan hyaluronate, which is more suitable than
albumin in supporting implantation in the mouse, and which will eliminate
biological variation and possible contamination from blood products. With the
routine culture of human blastocysts will come the introduction of non-invasive
tests of embryo viability, capable of identifying those blastocysts most likely
to develop from a given cohort. As the implantation rate of blastocysts is higher
than that of the cleavage stage embryo, fewer embryos will be required for
transfer in order to establish a successful pregnancy, thereby reducing the
number of multiple gestations and increasing the overall efficiency of human IVF.
PMID- 9755422
TI - Cryopreservation in human assisted reproduction is now routine for embryos but
remains a research procedure for oocytes.
AB - Human embryo cryopreservation represents an indispensable extension of in-vitro
fertilization (IVF) programmes as long as they are based upon the recovery of a
large number of oocytes. The most widely used procedures include the
cryopreservation of human zygotes or embryos in early cleavage, using 1,2
propanediol and sucrose as cryoprotectants. Our results over a 10 year period
(1986-1995) on 5032 thawed cycles involving 14 222 stored embryos make it
possible to appraise the results and the contribution of embryo freezing to
assisted reproduction. Embryos survived the freeze-thaw process in 73% of cases
leading to 4590 transfers of 2.2 embryos (91% of thawed cycles). The clinical
pregnancy rate per transfer was 16%, the live birth rate 12%, and the rate of
babies born alive per transferred embryo was 6%. Embryo freezing monitored 10
years later produced an average of 8% of additional births. By then, 86% of
stored embryos had been thawed for transfer to patients. Destruction or donation
were required for only 8% of all frozen embryos and there was no news from the
parental couple in relation to almost 6% of embryos. The fate of the vast
majority of embryos was decided during the first 5 years of storage. Blastocyst
cryopreservation is making new strides, thanks to co-culture systems and embryo
selection. Micromanipulation procedures seem to have little impact on the outcome
of embryo freezing. Human oocyte freezing is again clinically applied. Indeed,
much of the concern about injuries to the oocyte structures through the freeze
thaw process do not seem to be justified, and the problems with frozen-thawed
oocyte fertilization has been overcome using intracytoplasmic sperm injection
(ICSI). As long as oocyte in-vitro maturation is not well controlled, better
results will probably be obtained with mature oocyte cryopreservation. Emerging
methods include the freezing of immature oocytes, follicles and ovarian tissue.
PMID- 9755423
TI - Genetic regulation of egg and embryo survival.
AB - In both mice and humans, 15-50% of embryos die during the preimplantation period
from mechanisms that are largely unknown. Two major criteria predict
preimplantation embryo quality, the rate of development and the degree of
fragmentation. We review evidence that both of these criteria have a genetic
basis. Rate of development and subsequent embryo survival are controlled by a
gene, Ped, we discovered in the mouse. Although progress is being made in the
search for the human homologue of the mouse Ped gene, it has not yet been
identified. Fragmentation, observed in both mouse and human embryos, is probably
the result of apoptosis. We analysed transcription of two genes that regulate
apoptosis, bcl-2 and bax, and found that both are transcribed in mouse and human
preimplantation embryos. Overall, the literature reviewed and new data presented
in this paper support the concept that there is a genetic basis for
preimplantation egg and embryo survival.
PMID- 9755424
TI - How to avoid multiple pregnancies in assisted reproduction.
AB - The international rates of triplet or higher order pregnancies after assisted
reproduction are 7.3% at conception, 6.5% before reduction and 3.85% at birth.
The obstetric and neonatal outcomes for twins and triplets show that reducing the
proportion of multiple pregnancies should be a goal for centres undertaking in
vitro fertilization (IVF) and embryo transfer.
PMID- 9755425
TI - Molecular interactions between embryo and uterus in the adhesion phase of human
implantation.
AB - Molecular interactions at the embryo-maternal interface at the time of
implantation is an exciting field demanding a wide effort in order to understand
the crucial process of embryonic implantation. The objective of the present work
is to demonstrate the existence of a specific communication pathway (at the
molecular level) between embryo and endometrium in the adhesion phase of human
embryonic implantation. This pathway of molecular interactions is apparently
initiated by the endometrium in the presence of an implanting blastocyst. It is
mediated through the embryonic interleukin 0(IL)-1-alpha + IL-1-beta, and the
target is the endometrial epithelial beta-3 integrin subunit. If the relevance of
beta-3 is accepted as a marker of uterine receptively, these observations may
imply that the normal hormonally-regulated human endometrium is the trigger of
molecular events preparing the blastocyst to efficiently communicate and regulate
endometrial adhesion molecules in order to implant.
PMID- 9755426
TI - The role of leukemia inhibitory factor and interleukin-6 in human reproduction.
AB - There is now strong evidence that many of the actions of steroids in controlling
reproduction are mediated by locally acting factors such as growth factors and
cytokines. These have been shown to act both in an autocrine and paracrine manner
to regulate preimplantation embryo development and migration which is necessary
for placental development. The creation of mouse strains lacking genes for
receptors or growth factors has proved important in defining which of these are
essential in reproduction in this species and those that play a lesser role.
Using this approach, a lack of leukemia inhibitory factor (LIF) in the murine
endometrium has been shown to result in failed implantation. Evidence from
infertile women supports the notion that abnormal expression of LIF, or the
related cytokine interleukin-6 (IL-6) in the endometrium may underlie some forms
of human infertility. This offers the opportunity for therapeutic intervention,
if levels of these cytokines can be altered in a specific and controlled way. The
recently described method of delivery of genes to the uterine epithelium provides
a powerful new approach by which this could be achieved. The ability to regulate
the function of specific genes in the endometrium by direct gene transfer raises
the prospect of novel opportunities for therapeutic intervention.
PMID- 9755427
TI - Endometrial integrins and the establishment of uterine receptivity.
AB - Our understanding of the factors responsible for the initial interaction between
maternal and embryonic epithelium leading to successful implantation remains
incomplete. Temporal and spatial expression of specific endometrial peptides may
contribute to the establishment of a period of uterine receptivity, whereby the
endometrium becomes hospitable to the implanting blastocyst. The failure to
establish receptivity may account for a significant number of cases of
infertility in the female, especially affecting women with luteal phase
deficiency, endometriosis, hydrosalpinges, recurrent pregnancy loss and
unexplained infertility. Integrins are a family of cell adhesion molecules that
have now been largely accepted as markers of uterine receptivity. Their pattern
of expression during the menstrual cycle suggests that integrins may also provide
a means to study the factors that regulate the establishment of uterine
receptivity in general. The vitronectin receptor is an alpha-v-beta-3 integrin
that appears during the opening of the putative window of implantation. Its
expression appears to be associated with the down-regulation of epithelial
oestrogen and progesterone receptors (PR). We postulate that the selective loss
of PR on endometrial epithelium is critical to the establishment of uterine
receptivity and allows the emergence of paracrine influence by underlying stroma
through specific growth factors. Disruption of the normal pattern of integrins
found in certain infertility states may also reflect a shift in the paracrine
milieu, possibly due to the influence of inflammatory cytokines associated with
endometriosis or tubal disease. Understanding what regulates and dysregulates
endometrial integrins may lead to better treatment and diagnostic strategies for
infertility patients as well as novel approaches to contraception.
PMID- 9755428
TI - Glycodelins: role in regulation of reproduction, potential for contraceptive
development and diagnosis of male infertility.
AB - Glycodelins are glycoproteins synthesized in various glands, with sequence
homology to beta-lactoglobulins, and named according to their unique
oligosaccharide structures. We purified, cloned and sequenced endometrium- and
seminal plasma-derived glycodelins (GdA and GdS respectively) and found that they
are involved in various types of cell-cell communications. These include
interactions between the spermatozoon and the egg, and between immune cells and
their targets. Endometrial GdA inhibits sperm-egg binding, whereas the
differently glycosylated GdS in seminal plasma does not. These observation are of
interest for reproductive physiology, detection of causes of infertility, and
they also may have potential for contraceptive development.
PMID- 9755429
TI - New concepts in embryonic growth and implantation.
PMID- 9755432
TI - [In vitro antibacterial activity of vancomycin in combination with panipenem
against carbapenem-resistant MRSA].
AB - The synergistic relationship between vancomycin (VCM) and carbapenem (CRB) has
been reported in antibacterial activity against CRB-resistant strains of MRSA.
The purpose of this study is to investigate the antibacterial activity against
CRB-resistant MRSA using VCM, panipenem (PAPM), and a combination of both. 8
strains of CRB-resistant MRSA were used to examine the effects of these
antibiotics by the broth microdiluton technique. The effect of pH (pH 6, 7, 8) on
MIC of VCM alone was not observed in 7 out of 8 strains; MICs were between 1.0
2.0 micrograms/ml. PAPM alone, however, showed an enhancing tendency in alkaline
condition in 6 out of 8 strains. There was no influence of pH on MICs in the
combination use of VCM and PAPM, showing additive effect in 1 strain and
synergistic in 6 strains. Killing-curves against PAPM-resistant MRSA were
examined under the following drug combinations; 1/4 MIC of VCM (0.5
micrograms/ml) plus 1/4 MIC of PAPM (16 micrograms/ml), and 1/4 MIC of VCM plus
1/8 MIC of PAPM (8 micrograms/ml). The former drug combination showed synersistic
effect; decrease from 1.05 x 10(5) to 6.45 x 10(4) CFU/ml after 6 hours'
incubation and to less than 10 CFU/ml after 24 hours. The latter drug combination
showed synergistic activity (2.68 x 10(2) CFU/ml) after 24 hours' incubation, but
lost antibacterial activity after 48 hours. In conclusion, PAPM in combination
with VCM showed synergistic effects on CRB-resistant MRSA. This combination
therapy should be evaluated for the treatment of MRSA infection in patients with
renal dysfunction.
PMID- 9755430
TI - [Susceptibilities of bacteria isolated from patients with lower respiratory
infectious diseases to antibiotics (1996)].
AB - The bacteria isolated from the patients with lower respiratory tract infections
were collected by institutions located throughout Japan, since 1981. Ikemoto et
al. have been investigating susceptibilities of these isolates to various
antibacterial agents and antibiotics, and characteristics of the patients and
isolates from them each year. Results obtained from these investigations are
discussed. In 16 institutions around the entire Japan, 557 strains of presumably
etiological bacteria were isolated mainly from the sputa of 449 patients with
lower respiratory tract infections during the period from October 1996 to
September 1997. MICs of various antibacterial agents and antibiotics were
determined against 98 strains of Staphylococcus aureus, 93 strains of
Streptococcus pneumoniae, 84 strains of Haemophilus influenzae, 84 strains of
Pseudomonas aeruginosa (non-mucoid strains), 17 strains of Pseudomonas aeruginosa
(mucoid strains), 31 strains of Moraxella subgenus Branhamella catarrhalis, 21
strains of Klebsiella pneumoniae etc., and the drug susceptibilities of these
strains were assessed except for those strains that died during transportation.
1) S. aureus S. aureus strains for which MICs of oxacillin (MPIPC) were higher
than 4 micrograms/ml (methicillin-resistant S. aureus) accounted for 67.3%. The
frequency of the drug resistant bacteria increased comparing to the previous
year's 52.7%. Arbekacin (ABK) and vancomycin (VCM) showed the highest activities
against both S. aureus and MRSA with MIC80s of 1 microgram/ml. 2) S. pneumoniae
Imipenem (IPM) and panipenem (PAPM) of carbapenems showed the most potent
activities with MIC80s of 0.063 microgram/ml. Faropenem (FRPM) showed the next
potent activity with MIC80 of 0.125 microgram/ml. The other drugs except
erythromycin (EM), clindamycin (CLDM) and tetracycline (TC) were active against
S. pneumoniae tested with MIC80s of 8 micrograms/ml or below. 3) H. influenzae
The activities of all drugs were potent against H. influenzae tested with MIC80s
of 4 micrograms/ml or below. Cefotiam (CTM), cefmenoxime (CMX), cefditoren (CDTR)
and ofloxacin (OFLX) showed the most potent activities with MIC80s of 0.063
microgram/ml. 4) P. aeruginosa (mucoid strains) Tobramycin (TOB) showed the most
potent activity against P. aeruginosa (mucoid strains) with MIC80 of 1
microgram/ml. Ceftazidime (CAZ), cefsulodin (CFS), IPM, gentamicin (GM), ABK and
ciprofloxacin (CPFX) showed the next potent activities, with MIC80s of 2
micrograms/ml. The MIC80s of the other drugs ranged from 4 micrograms/ml to 16
micrograms/ml. 5) P. aeruginosa (non-mucoid strains) TOB and CPFX showed the most
potent activities against P. aeruginosa (non-mucoid strains) with MIC80s of 1
microgram/ml. The MIC80s of piperacillin (PIPC) and cefoperazone (CPZ) were 16
micrograms/ml in 1995, and they were 64 micrograms/ml in 1996. 6) K. pneumoniae
All drugs except ampicillin (ABPC) were active against K. pneumoniae. CMX,
cefpirome (CPR), cefozopran (CZOP) and carumonam (CRMN) showed the most potent
activities against K. pneumoniae with MIC80s of 0.125 microgram/ml. The MIC80s of
the other drugs ranged from 0.25 microgram/ml to 2 micrograms/ml. 7) M.(B)
catarrhalis Against M.(B.) catarrhalis, all drugs showed good activities with
MICs of 4 micrograms/ml or below. IPM and minocycline (MINO) showed the most
potent activities with MICs of 0.063 microgram/ml. Also, we investigated year to
year changes in the characteristics of patients, their respiratory infectious
diseases, and the etiology. Patients' backgrounds were examined for 557 isolates
from 449 cases. The examination of age distribution indicated that the proportion
of patients with ages over 60 years was 71.0% of all the patients showing a
slight increase over that in 1994. Proportions of diagnosed diseases were as
follows: Bacterial pneumonia and chronic bronchitis were the most frequent with
35.9% and 30.3% respectively. They were followed by bronchiectasis with a
proportion of 10.
PMID- 9755431
TI - [Evaluation of antibacterial activities of various antibiotics against glucose
non-fermentative gram-negative rods other than Pseudomonas aeruginosa].
AB - MICs of piperacillin, sulbactam/cefoperazone, minocycline (MINO), gentamicin,
amikacin, flomoxef, ceftazidime, cefozopran, cefsulodin and imipenem were
determined, against 189 clinical isolated strains of glucose non-fermentative
Gram-negative Rods (NFGNR; Acinetobacter baumannii (44), Alcaligenes faecalis
(5), Alcaligenes xylosoxidans (25), Burkholderia cepacia (12), Chryseobacterium
indologenes (23), Chryseobacterium meningosepticum (9), Pseudomonas fluorescens
(8), Pseudomonas putida (12), Stenotrophomonas maltophilia (51). Most species of
these NFGNR show resistance to many antibiotics tested. Among the antibiotics
used in this study, the only antibiotic effective against all species of NFGNR
tested is MINO. The spectrums of antibacterial activities of various antibiotics
determined by MICs may be useful in preliminary test for identification of these
NFGNR.
PMID- 9755433
TI - [Resistance to macrolide antibiotics found in methicillin-resistant Japanese
clinical isolates of Staphylococcus aureus in 1996].
AB - Minimum inhibitory concentrations (MICs) of erythromycin, clarithromycin,
roxithromycin, oleandomycin, triacetyloleandomycin, azithromycin, josamycin and
midecamycin were investigated using 200 strains of methicillin-resistant
Staphylococcus aureus (MRSA) clinically isolated in Japan during 1996. The
results show that the MRSAs could be classified into five groups according to MIC
patterns to various macrolides and that more than 88% of the strains used were
highly-resistant to all macrolides tested. It was found that 9.0% of the strains
examined showed a unique MIC pattern different to that of macrolide-lincosamide
streptogramin B antibiotic resistance type. This group was found to be highly
resistant to 14-membered but susceptible to 16-membered macrolides. The
resistance induction by erythromycin or oleandomycin was observed to increase for
clarithromycin and roxithromycin resistances in a part of strains used. On the
other hand, for azithromycin, such induction was not observed.
PMID- 9755434
TI - Indium-111 satumomab pendetide: the first FDA-approved monoclonal antibody for
tumor imaging.
AB - OBJECTIVE: Colon cancer is the second most common cause of cancer mortality.
Ovarian cancer is the most common gynecologic malignancy cause of death in women.
A labeled monoclonal antibody attaches to a tumor-associated antigen and allows
these tumor masses to be imaged or treated, depending on the radionuclide used.
Indium-111 satumomab pendetide was the first labeled monoclonal antibody to be
approved by the Food and Drug Administration (FDA) for tumor imaging. It is
reactive with most colorectal and ovarian cancers, as well as other cancers.
After reading this article, the technologist will understand the FDA approval
process, phase trial results, safety and adverse reactions, human antimurine
antibody response, indications, imaging protocol, and strengths and weaknesses of
imaging with satumomab pendetide. Representative cases are presented.
PMID- 9755435
TI - Nuclear cardiology, Part III: Scintigraphic evaluation of cardiac perfusion.
AB - OBJECTIVE: After reading Part III of this series of nuclear cardiology articles,
the technologist should be able to: (a) compare and contrast radiopharmaceuticals
used for myocardial perfusion imaging; (b) describe imaging protocols used for
detecting coronary artery disease; and (c) describe imaging patterns seen
following reconstruction of myocardial images.
PMID- 9755437
TI - Effects of the attenuation map used in the Chang algorithm on quantitative SPECT
results.
AB - OBJECTIVE: This study examined the effects on SPECT quantitation caused by
erroneous size and position of the attenuation map and inaccurate pixel size used
in the Chang algorithm. METHODS: Projection data of a three-dimensional head
phantom were simulated with a uniform attenuation coefficient of 0.15/cm for the
inside of the phantom. Images were reconstructed using the filtered
backprojection algorithm without attenuation compensation and the Chang algorithm
with different attenuation maps. Quantitative comparison then was performed
between the reconstructed images and the phantom. RESULTS: The pixel values
obtained for noisy data by using the first-order Chang algorithm with an accurate
attenuation map were less than 10% different from the true values and the left
right asymmetry was under 5%. Small errors in the geometric parameters of the
attenuation map, however, caused considerable quantitative inaccuracy in the
reconstructed image. For example, a 0.64-cm error in the size of the map caused
10% deviation from the true value and a 0.64-cm shift of the position of the map
towards the left produced 10% left-right pixel value asymmetry. CONCLUSION: The
accuracy of the Chang algorithm critically depends on the geometric parameters.
For a uniform attenuator with symmetric geometry, such as the human brain, a true
left-right symmetry in the pixel value can be altered significantly by a small
error in the geometric parameters, while symmetry can be maintained with no
attenuation compensation.
PMID- 9755436
TI - Dual-isotope protocol for indium-111 capromab pendetide monoclonal antibody
imaging.
AB - OBJECTIVE: A dual-isotope imaging protocol using 99mTc-labeled red blood cells
with 111In capromab pendetide monoclonal antibody imaging for detective and
localizing nodal metastasis in prostate cancer is described. METHODS: This
protocol involves a single SPECT acquisition that is less time consuming and more
comfortable for the patient than the currently recommended method, which requires
two separate SPECT acquisitions performed on different days. RESULTS: Forty
patients were studied with the dual-isotope protocol. Preliminary data suggest
increased accuracy compared with the single-isotope technique. CONCLUSION: The
dual-isotope technique assures the precise image registration needed for accurate
comparison of blood pool and pelvic lymph node activity that is required for
confident and accurate image interpretation.
PMID- 9755438
TI - Effect of time on liver clearance of technetium-99m-tetrofosmin in patients with
acute chest pain: when should imaging begin?
AB - OBJECTIVE: Due to stable myocardial retention and technetium imaging
characteristics, 99mTc-tetrofosmin has been considered potentially useful for
acute chest pain imaging. Tetrofosmin also has favorable biokinetics with
reported rapid liver clearance, 5 min poststress and 30-45 min post-rest
injection. Since comparable data are not available, the effect of time on liver
clearance was evaluated in patients with acute chest pain. METHODS: One hundred
six patients received an intravenous injection of 25-30 mCi 99mTc-tetrofosmin to
evaluate acute chest pain. SPECT imaging was performed 15-120 min after injection
of the tracer. Patient images were grouped according to the time of acquisition
after acute injection: 15-30 min, 31-45 min, 46-60 min, 61-90 min and > 90 min.
Quantitative analysis was performed of a similar anterior projection for each
patient consisting of 6 X 6-pixel region of interest over the myocardium and
adjacent liver. Average counts per pixel were determined and a heart/liver (H/Li)
ratio was calculated. RESULTS: The mean H/Li ratio was < 1.0 for patient images
acquired 15-45 min after injection, and > 1.0 for patient images acquired after
45 min. The difference was statistically significant (p < 0.05). CONCLUSION:
Quantitative analysis suggests that the optimal imaging time should be at least
45 min after the injection of 99mTc-tetrofosmin to allow adequate liver clearance
before image acquisition of acute chest pain syndromes.
PMID- 9755439
TI - Measurement of blood radioactivity for quantification of cerebral blood flow
using a gamma camera.
AB - OBJECTIVE: This study was designed to determine whether gamma cameras can be
substituted for well-type scintillation counters in measuring blood radioactivity
counts to be used as an input function for the quantitative measurement of
cerebral blood flow (CBF). METHODS: Twelve different aqueous 123I solutions were
prepared by serial dilution of the original concentration of 281.9 kBq/ml, and
the radioactivity count of each dilution was measured with a gamma camera with
the collimator removed, and with a well-type scintillation counter. When
measuring the radioactivity counts with a gamma camera, static images were
acquired using a 128 x 128 matrix for 5 min, and the regions of interest with 14
x 14 pixels (21 mm x 21 mm) were defined. RESULTS: There was a good correlation
between the results obtained by these two procedures in the range of
concentration between 0.008 kBq/ml and 281.9 kBq/ml (y = 4.245x-2.549, r = 1.0, n
= 12, s.e.e. = 7.217 kcpm). There was good agreement between the CBF values
(ml/100 g/min) obtained using the cross-calibration factor (CCF) and blood
radioactivity counts measured with the two procedures (y = 0.990x + 0.552, r =
0.990, n = 231, s.e.e. = 1.340 ml/100 g/min). CONCLUSION: The results suggest
that gamma cameras can be substituted for well-type scintillation counters in the
quantitative measurement of CBF, and make it unnecessary to measure CCF after
routine calibration of a SPECT apparatus.
PMID- 9755440
TI - Adsorption of some technetium-99m radiopharmaceuticals onto disposable plastic
syringes.
AB - OBJECTIVE: The purpose of this study was to determine the adsorption behavior of
some widely used, commercially available 99mTc radiopharmaceuticals onto
different types of plastic syringes. METHODS: Kits were reconstituted with 99mTc
pertechnetate diluted with 0.9% saline to produce maximum radioactive
concentrations, as stated by the manufacturers. Aliquots of the solutions were
transferred to four different brands of 2-ml syringes. The activity in the
syringes was measured before and after injections or simulated injections. The
amount adsorbed to the plastic syringe barrel and plunger before and after
washout also was measured at different time intervals. Comparisons between
products from different manufacturers were made for 99mTc succimer (DMSA) and
99mTc macroaggregated albumin (MAA). RESULTS: Some 99mTC preparations undergo
significant adsorption to plastic syringes. Adsorption differs considerably
between products from different manufacturers. There was significantly higher
residual activity in some types of syringes. In some cases the residual was as
high as 40%-50% of the initial activity, and most of the adsorption occurred
within 15 min of filling the syringe. CONCLUSION: The data suggest that the
extent of adsorption depends on pharmaceutical excipients in the kits and/or the
type of syringe used. When inappropriate syringes are used, the reduction in the
administered activity may result in poor-quality images. Therefore, the
compatibility between radiopharmaceutical and syringe should be investigated
under normal conditions of preparation and use every time a new brand of syringe
or a new radiopharmaceutical comes into use in diagnostic nuclear medicine.
PMID- 9755441
TI - The incidence of blood contamination of lead unit dose containers with and
without single-use protective inserts used with commercially prepared
radiopharmaceutical unit doses.
AB - OBJECTIVE: This investigation evaluated the effectiveness of disposable plastic
inserts in radiopharmaceutical unit dose lead containers (pigs) in preventing the
distribution of doses in blood-contaminated containers. Technologists commonly
dispose of the syringes by placing them into the lead pigs, leaving the needles
uncapped. This process raises the question of unsuspected blood contamination of
these pigs. Consequently, the distribution of commercially prepared
radiopharmaceutical doses in reusable lead pigs may result in radiopharmaceutical
doses being distributed in containers that are contaminated with blood. METHODS:
Using a simple chemical wipe test designed to determine the presence or absence
of blood contamination, 618 pigs from commercial radiopharmacies throughout the
U.S. were tested for contamination. The inside of the pigs and inserts, if
present, were wiped before and after dose administration. Of the pigs tested, 292
came from radiopharmacies that used a protective, disposable plastic insert
inside the pig, and 326 came from radiopharmacies that did not use an insert.
RESULTS: Of those pigs without the protective disposable inserts, 39.3% arrived
in the nuclear medicine department in pigs contaminated with blood. Of those pigs
with inserts, 1% arrived with blood-contaminated inserts. After dose
administration, 46.3% of the pigs without inserts were contaminated with blood
and 3% of the protective inserts were contaminated. CONCLUSION: The proper use of
disposable plastic inserts reduces the possibility of distributing
radiopharmaceutical unit doses in containers contaminated with blood.
PMID- 9755442
TI - A safe, simple method for preparing heat-damaged red cells for diagnosing splenic
infarct or trauma.
AB - OBJECTIVE: The purpose of this study was to demonstrate a fast, safe and simple
method for preparing heat-damaged red blood cells. METHODS: Patient blood was
radiolabeled using the Ultra-Tag RBC kit and then heated to 49.5 degrees C for 20
min. The reaction vial was cooled in ice water for 1 min and the required
activity was administered to the patient. The patient was imaged 60 min
postinjection. RESULTS: High-quality planar and SPECT images of the spleen were
obtained with low background activity noted. Radiolabeling efficiency was greater
than 95%. CONCLUSION: The method was safe and simple to perform. High-quality
images of the spleen were obtained.
PMID- 9755443
TI - Radiation safety when a patient dies after therapy.
AB - OBJECTIVE: When a patient dies a short time after radionuclide therapy, several
issues arise due to the shifting of responsibility from patient care to
protection of the public, while respecting societal values and rites. Such a
situation occurred in our institution after administering a large therapeutic
dose of 131I for metastatic thyroid cancer. The requirements of safe practice,
the shift accountability, the ethical aspects and forthcoming changes in the
regulatory constraints are discussed.
PMID- 9755444
TI - 'Nano-dumpling' with drug delivery potential.
PMID- 9755445
TI - Cost-effective carbohydrate synthesis permits large-scale production of an anti
inflammatory drug.
PMID- 9755446
TI - Combining strategies to improve non-viral vectors.
PMID- 9755447
TI - Early-warning cancer tests in development.
PMID- 9755448
TI - Cancer vaccines '98: a reductionistic approach. Bethesda, MD, USA, 27-28 April
1998.
PMID- 9755449
TI - Multiple sclerosis: modelling the future. The Multiple Sclerosis Society of Great
Britain and Northern Ireland Conference: Frontiers in Science and Patient Care
Disease Management.
PMID- 9755451
TI - Data disclosure in the human genome project.
PMID- 9755450
TI - Tuberculosis research comes of age. Keystone Symposium on Tuberculosis: Molecular
Mechanisms and Immunologic Aspects.
PMID- 9755452
TI - Restricted inflammatory reaction in the CNS: a key impediment to axonal
regeneration?
AB - Axons in the central nervous system (CNS) of adult mammals do not regenerate
after injury. Mammalian CNS differs in this respect from other mammalian tissues,
including the peripheral nervous system (PNS), and from the CNS of lower
vertebrates. In most parts of the body, including the nervous system, injury
triggers an inflammatory reaction involving macrophages. This reaction is needed
for tissue healing; when it is delayed or insufficient, healing is incomplete.
The CNS, although needing an efficient inflammatory reaction resembling that in
the periphery for tissue healing, appears to have lost the ability to supply it.
We suggest that restricted CNS recruitment and activation of macrophages are
linked to regeneration failure and might reflect the immune privilege that
characterizes the mammalian CNS. As macrophages play a critical role in tissue
restoration, and because their recruitment and activation are among the most
upstream of the events leading to tissue healing, overcoming the deficiencies in
these steps might trigger a self-repair processing leading to recovery after CNS
injury.
PMID- 9755454
TI - Congenital heart defects and 22q11 deletions: which genes count?
AB - Hemizygous deletions on the long arm of chromosome 22 (del22q11) are a relatively
common cause of congenital heart disease. For some specific heart defects such as
interrupted aortic arch type B and tetralogy of Fallot with absent pulmonary
valve, del22q11 is probably the most frequent genetic cause. Although extensive
gene searches have been successful in discovering many novel genes in the deleted
segment, standard positional cloning has so far failed to demonstrate a role for
any of these genes in the disease. We show how the use of experimental animal
models is beginning to provide an insight into the developmental role of some of
these genes, while novel genome manipulation technologies promise to dissect the
genetic aspects of this complex syndrome.
PMID- 9755453
TI - Human developmental disorders and the Sonic hedgehog pathway.
AB - Sonic hedgehog (Shh) is a morphogen that is crucial for normal development of a
variety of organ systems, including the brain and spinal cord, the eye,
craniofacial structures, and the limbs. Mutations in the human SHH gene and genes
that encode its downstream intracellular signaling pathway cause several clinical
disorders. These include holoprosencephaly (HPE, the most common anomaly of the
developing forebrain), nevoid basal cell carcinoma syndrome, sporadic tumors,
including basal cell carcinomas, and three distinct congenital disorders: Greig
syndrome Pallister-Hall syndrome, and isolated postaxial polydactyly. These
conditions caused by abnormalities in the SHH pathway demonstrate the crucial
role of SHH in complex developmental processes, and molecular analyses of these
disorders provide insight into the normal function of the SHH pathway in human
development.
PMID- 9755455
TI - Transcription-factor-modulating agents: precision and selectivity in drug design.
AB - Transcription factors play an important role in the long-term regulation of cell
growth, differentiation and responses to environmental cues. There is growing
evidence that these proteins are closely associated with control at the genetic
level of the development and maintenance of the diseased state, and might
therefore provide selective targets for novel pharmaceutical intervention. The
vast array of information available on the three-dimensional structure of
transcription factors and the intricate molecular machineries that fine-tune
their activity offer opportunities for embarking on the rational design of drugs
directed against specific transcription factors, thus producing potent new agents
that modulate their function in a plethora of clinically important situations.
PMID- 9755457
TI - [Genetic polymorphism of drug metabolizing enzymes: new mutations in CYP2D6 and
CYP2A6 genes in Japanese].
AB - Interindividual variation of drug effects in humans can be attributed to many
factors. Among the factors, the rate of drug metabolism has been regarded as the
most important one. A genetic defect of enzymes involved in drug metabolism,
particularly cytochrome P450 (CYP), has been believed to be one of the important
causal factors of adverse drug reactions. There are multiple gene mutations for
CYP causing the poor metabolizer phenotype. The occurrence of genetic
polymorphism has been seen in genes for CYP1A1, CYP2A6, CYP2C9, CYP2D19, CYP2D6,
CYP2E1 and CYP3A5. Among them, the molecular mechanisms of genetic polymorphisms
of CYP2D6 (debrisoquine/sparteine type) and CYP2A6 (coumarin type) in Japanese
have been the focus of investigations. Only 20-30% of the Japanese population
that shows the CYP2D6 poor metabolizer phenotype can be diagnosed by gene
analysis. By other means, we found two new mutations, CYP2D6/J9 and CYP2D6/C8, in
Japanese. With regard to CYP2A6, we discovered SM-12502, a new probe drug in
addition to coumarin, that is currently under development; this drug is mainly
metabolized by CYP2A6. Using this drug as a probe, we found poor metabolizers and
analyzed the genes for CYP2A6. We found a new mutation (CYP2A6 whole deletion)
responsible for the poor metabolizer phenotype. These results should contribute
to the selection of an effective drug prescription and a reduced incidence of
adverse effects.
PMID- 9755458
TI - [Genetic polymorphism of the CYP2C subfamily].
AB - Cytochromes P450 (CYP) are a superfamily of hemoproteins that metabolize various
foreign compounds. The human CYP2C subfamily is one of the subfamilies of the
CYP2 family and it consists of four members of CYP isoforms, CYP2C8, CYP2C9,
CYP2C18 and CYP2C19. A well-characterized genetic polymorphism occurs in CYP2C19,
which is associated with the 4'-hydroxylation of S-mephenytoin. There are two
phenotypes, extensive metabolizers and poor metabolizers (PM) of mephenytoin. The
frequency of PM in the Japanese population is 20%, while only 3% of Caucasians
are PM of mephenytoin. Two defective alleles, designated as CYP2C19*2 and
CYP2C19*3, have been described, and the latter mutation has been detected only in
Oriental populations. Recently, an allelic variant of CYP2C9 that causes
substitution of Leu359 for Ile359 has been shown to be associated with the
decreased metabolic clearance of various therapeutic agents including warfarin,
tolbutamide and phenytoin. The frequency of this variant allele in the Japanese
population is 2%, while those of the Caucasians are 6-9%. Although the role of
CYP2C18 in the drug metabolism remains obscure, we have recently found that
defective alleles of CYP2C19*3 and CYP2C18m1 are completely linked, suggesting
that PM of CYP2C19 with CYP2C19*3 alleles is a PM of CYP2C18 and vice versa.
PMID- 9755459
TI - [The physiological role of P450-derived arachidonic acid metabolites].
AB - Arachidonic acid is metabolized to biologically active substances by three major
enzyme systems including cyclooxygenases, lipoxygenases and cytochrome P450s. The
third pathway, P450-dependent pathway, includes allylic oxidation, omega
hydroxylation, and epoxidation of arachidonic acid. Of these metabolites, the
physiological role of 20-hydroxyeicosatetraenoic acid (20-HETE) produced by CYP4A
isoforms has been extensively studied. 20-HETE affects ion transport, constricts
blood vessels and participates in tubuloglomerular feed back. Increased
production of 20-HETE is a major factor in elevating blood pressure in
spontaneously hypertensive rats (SHR). We have found that CYP4A2 level in SHR is
much higher than that of normotensive rat. Recently, factors of endothelial
origin other than nitric oxide and prostaglandins were reported. Inhibitors of
P450-dependent arachidonic acid metabolism greatly reduce the vasodilator effect
and this factor is speculated to be an epoxide of arachidonic acid. We have
isolated CYP2C23 from rat kidney and have found that it produces arachidonic acid
epoxides. We have investigated changes in the CYP2C23 levels in physiological and
pathophysiological conditions. Multiple pathways of arachidonic acid metabolism
by P450 have been reported and the diverse properties of these metabolites and
the wide distribution of the P450 system make them prime candidates for
participation in regulatory mechanisms of the circulation and transporting
epithelia.
PMID- 9755460
TI - [Inhibition of cytochrome P450 by nitric oxide].
AB - Nitric oxide (NO) reacts with iron, superoxide, thiols and oxygen. Although NO
reversibly interacts with the heme-iron of P450, the pathophysiological role of
this interaction remains to be elucidated. We found that hepatic levels of P450
markedly decreased in endotoxemic rats, particularly when the rate of NO
generation was increased. To determine the possible role of NO in the modulation
of the structure and function of P450, changes in the levels and activities of
P450 isozymes were determined in liver microsomes from normal and endotoxemic
rats. Electron spin resonance analysis revealed that incubation of microsomes
with the NO donor NOC-7 rapidly generated NO-P450 adducts. Microsomal levels of
NO-P450 adducts increased and peaked at 10 min after incubation and decreased
thereafter; it disappeared completely within 60 min. In contrast, microsomal
levels of the low-spin ferric form and CO-differential spectrally detectable P450
rapidly decreased during the initial 10 min; the signal intensity for P450
recovered thereafter. Western blot analysis using specific antibodies against
CYP3A2 and CYP2C11 isozymes revealed no detectable degradation of these isoforms.
Effect of NO on the catalytic activity of the enzymes was also determined by
using testosterone as the substrate. The hydroxylation activity in microsomes
rapidly decreased during the initial 10 min and disappeared slowly thereafter.
These results suggested that NO might form dissociable complexes with the heme
moiety of P450 and irreversibly inactivate them. The mechanism for P450
inactivation by NO and the role of NO-P450 interaction in the pathogenesis of
liver injury in endotoxemia are discussed.
PMID- 9755461
TI - [The regulation of steroidogenesis by 17 alpha-hydroxylase/17,20-lyase
(P450c17)].
AB - Cytochrome P450c17 (P450c17) catalyzes 17 alpha-hydroxylation and 17, 20-lyase
reactions. This enzyme plays a key role in determination of the balance between
glucocorticoids and steroid sex hormones. In this review we discuss recent
progress in the studies of both transcriptional regulation of CYP17 encoding
P450c17 and enzymatic regulation of P450c17. Several transcription factors
involved in cAMP-dependent transcription of the gene have been isolated and
identified to be members of the atypical homeodomain "TALE" superfamily
containing Pbx, Meis, Pknox and TGIF families. The studies of enzymatic
regulation of P450c17 suggest that cytochrome b5 (b5), a heme protein, may switch
the reaction of P450c17 by enhancing the 17, 20-lyase activity to increase the
level of plasma C19 steroids. The importance of b5 in the synthesis of C19
steroids has also been shown in a clinical study reporting that the external
genitalia was abnormal in a patient having a defect in b5. Therefore, this
enhancement by b5 on the lyase activity of P450c17 may be essential to normal
sexual differentiation in humans and also important in control of an optimal
balance between sex steroid hormones and glucocorticoids. In addition, the age
dependent expression of P450c17 in immature rat livers is also discussed.
PMID- 9755462
TI - [A new aspect of the pharmacological and physiological significance of the
aromatase/estrogen system].
AB - Aromatase (estrogen synthetase) catalyzes a key step in estrogen biosynthesis and
plays an important role in reproductive processes in the ovary and placenta. In
this context, aromatase is an enzyme producing estrogen as an endocrine female
sex hormone. Recently, it has reported that aromatase is also present in various
extra-gonadal tissues and is tissue-specifically regulated by various factors.
This tissue-specific regulation of human aromatase gene is realized by
alternative utilization of multiple exon 1's; exons la, 1b, 1c, 1d, 1e, and 1f
that are specific for expression in the placenta, skin fibroblasts/fetal liver,
ovary, ovary/prostate/testis, placenta, and brain, respectively. Each of the
tissue-specific exon 1's is flanked by a unique promoter containing basic and
regulatory elements. The facts that (i) aromatase is distributed in various
gonadal and extra-gonadal tissues and (ii) regulated tissue-specifically by
various factors, (iii) estrogen participates in specific physiological functions
of various tissues, and (iv) estrogen receptor is also distributed in various
tissues strongly indicate that estrogen locally produced by aromatase acts in
various tissues as a multi-functional paracrine or autocrine hormone. This idea
was discussed in connection with the Kd value for the estrogen receptor and serum
concentration of estrogen.
PMID- 9755463
TI - [Production of various antibodies and single chain Fv molecule against signal
transducing proteins].
AB - In the present review, we described the procedures of production of polyclonal
and monoclonal antibodies and single chain Fv molecule (scFv). Among several
animal species, the rabbit is the best animal for polyclonal antibody production
and the mouse is the best animal for monoclonal antibody production. In this
review, we discussed problems that might be encountered when trying to produce
antibodies. Polyclonal antibodies are easily produced in rabbits by immunizing
them with glutathione-S-transferase fusion proteins. However, it is difficult to
eliminate nonspecifically reacting antibodies, even after the antibodies were
purified from sera by an antigen column. Monoclonal antibody production is a time
consuming process, but it successful, will produce a very useful reagent due to
no limitation of supply and constant quality. We described monoclonal antibody
production by means of glutathione-S-transferase fusion protein. scFv is a
portion of the antibody and is constructed by PCR of VH and VL regions of the
antibody. We recommend that scFv should be constructed from a hybridoma that
secretes monoclonal antibody, although some researchers have claimed that scFv
can be constructed from the spleen of immunized mice. The expression of scFv is a
promising approach to analyze the function of one of the subtypes, when the
original monoclonal antibody can block the function of the protein.
PMID- 9755464
TI - [Effects of personality, cognitive, and situational variables on risk taking
behavior].
AB - This study examined the effects of individual difference and situation on risk
taking behavior. In Experiment 1, 115 undergraduates completed a questionnaire of
personality (sensation seeking, optimism, etc.) and their risk taking behavior,
risk perception, and anxiety in eight situations: personal, social, gain-loss,
and loss situations. Results indicated an effect of personality on risk taking
behavior in personal gain-loss situations (sports and life event), which was
mediated by perceived risk controllability. In Experiment 2, 137 undergraduates
completed a questionnaire of personality, cognitive variables (risk perception,
own competence, and perceived cost and benefit), and risk taking behavior in
personal gain-loss situations (sports, life event, and gambling). Results of
covariance structure analysis showed that perceived risk controllability affected
the relationship between the variables. For instance, risk significance and
perceived cost and benefit mediated the effect of 'controllability with skills'
on risk taking behavior in the controllable situation (e.g., sports). Similarly,
competence and risk perception mediated the effect of 'uncontrollable luck
factors' in the chance situation (e.g., life event).
PMID- 9755465
TI - [The effects of media violence on affective, cognitive, and physiological
reactions of viewers].
AB - The present study investigated the effects of media violence on affective,
cognitive, and physiological reactions of viewers. Eighty undergraduate student
(male = 40, female = 40) participated in the experiment. First, subjects were
exposed to one of four violent films whose levels of violence and entertainment
were based on ratings taken in a previous study (Yoshida & Yukawa, 1996).
Immediately after viewing the film, subjects described their thoughts which
occurred during watching the film and rated their affective reactions toward the
film. Heart rate and eyeblink rate as indicators of physiological arousal were
measured continuously before, during, and after the film. Results showed that the
film high in violence elicited more negative and empty-powerless affects, while
the film high in entertainment evoked more positive affects.
PMID- 9755466
TI - [Delays in recognizing facial expressions resulting from prolonged viewing of
adaptation face stimuli].
AB - The main purpose of the present study was to investigate the mechanism underlying
fundamental dimensions in recognition of facial expressions, using the prolonged
viewing method. Pictures of female faces were used, which displayed one of the
following six: happiness, sadness, surprise, anger, disgust, and neutral
expressions. In Experiment 1, the mean ratings of each expression on each picture
were analyzed with principal component analysis (PCA). In Experiment 2, subjects
orally judged the expressions of test faces following either one or 25 seconds of
viewing of an adaptation face. Significant delays occurred in the prolonged
viewing condition only when the adaptation face had a higher absolute value on
'pleasantness' the first component of PCA, than the test face. In contrast,
adaptation faces that were high only on 'arousal,' the second component, produced
no such effects. It was suggested that there are at least two subsystems involved
in the recognition of facial expressions and that each system has different
temporal characteristics.
PMID- 9755467
TI - [Preference for high frequency sounds of contact calls in primates: Japanese
macaques and ringtailed lemurs].
AB - Preference for high frequency sounds in human infants are found by other
researchers. The purpose of this study is to examine whether nonhuman primates
also have the same tendency as human infants. It is important to consider
language origins. Two types of tape recorded coo calls, contact calls, with high
and low fundamental frequencies were played back as stimuli for two groups of
Japanese macaques (Macaca fuscata). The result showed that the animals of both
groups preferred high frequency sounds. To ascertain whether other species also
have the same tendency as the Japanese macaques, a playback experiment similar to
that for Japanese macaques was conducted for one group of ringtailed lemurs
(Lemur catta). Tape recorded mew calls, contact calls, were used as stimuli. The
results showed that ringtailed lemurs also preferred high frequency sounds.
Moreover, it was clarified by an additional playback experiment for one group of
Japanese macaques that animals had an affective preference for high frequency
sounds. These results suggest that nonhuman primates have a consistent tendency
to prefer high frequency sounds.
PMID- 9755468
TI - [Effects of modality on rats' short-term memory in successive matching-to-sample
task].
AB - This study examined the effects of modality on rats' short-term memory by using
the go/no-go delayed paired stimuli comparison task (Konorski task). Each of
paired stimuli (S1, S2) was successively presented in order with delay intervals,
and a food pellet was contingent upon the lever pressing only when S2 matched S1
(light; L or tone; T). The accuracy of discrimination between the matched and
nonmatched pairs decreased as a function of delay interval. Steeper forgetting
was shown when a visual stimulus was presented as S1 (S1-L trials) than when an
auditory S1 (S1-T trials) was presented. The longer was the ITI duration, the
better was the performance in the S1-T trials, but this was not true for the S1-L
trials. Further, discrimination performance was an increasing function of the
duration of S1 regardless of the modality of S1. These results were discussed
mainly on the basis of interference theory and decay theory of forgetting.
PMID- 9755469
TI - [Preschooler peer interaction and performance on Doise spatial task].
AB - Using Doise spatial task, this study examined the following three hypotheses
about preschoolers' attainment of spatial skills: (1) A different viewpoint
promotes faster advancement through developmental levels of spatial skills than
the same viewpoint. (2) An interaction partner with a different skill level,
rather than the same level, promotes faster advancement. And (3) a socio
cognitive conflict with the partner promotes faster advancement. To test these
hypotheses, the method of Doise and Mugny (1984) was used in Experiment 1. In
Experiment 2, the method was modified in several ways. Most notably by pointing
out and changing the shape of the marker, and by decreasing the number of objects
to be arranged. Results of the experiments supported Hypothesis 3, but not 1 or
2. It was concluded that socio-cognitive conflicts in preschooler peer
interaction contributed to children's development of spatial skills.
PMID- 9755470
TI - [Determinants of time-monitoring on prospective memory tasks].
AB - The purpose of this study was to examine determinants of time-monitoring to
clarify the cognitive process in prospective memory tasks (i.e., tasks which
require the timely execution of a previously intended action). Thirty-two
participants were asked to perform future activities three minutes after the
start of background tasks, and their time-monitoring responses were recorded. The
results showed that higher motivation and less cognitive load led to higher time
monitoring frequency and better performance in prospective memory tasks. However,
with time presentation, time-monitoring frequency could be reduced, while the
performance in prospective memory tasks was improved. The findings indicate that
information which facilitates the maintenance of inner time model is an important
factor for effective time-monitoring. This study suggested that frequency of time
monitoring could be regarded as a critical factor in the theoretical analysis of
prospective memory tasks.
PMID- 9755471
TI - [Subjective well-being and self acceptance].
AB - The purpose of the present study was to examine the relationship between
subjective well-being and self acceptance, and to design a happiness self-writing
program to increase self acceptance and subjective well-being of adolescents. In
study 1, we examined the relationship between social interaction and self
acceptance. In study 2, we created a happiness self-writing program in cognitive
behavioral approach, and examined whether the program promoted self acceptance
and subjective well-being. Results indicated that acceptance of self-openness, an
aspect of self acceptance, was related to subjective well-being. The happiness
self-writing program increased subjective well-being, but it was not found to
have increased self acceptance. It was discussed why the program could promote
subjective well-being, but not self acceptance.
PMID- 9755472
TI - [Contingent negative variation (CNV) in the detection of deception task using a
serial presentation of pictures].
AB - The purpose of the experiment was to investigate the feasibility of using
contingent negative variation (CNV) as an index of detection of deception. Twelve
subjects were required to complete both an innocent and guilty condition in that
order. In the innocent condition, a series of six pictures, two of which depicted
different landscapes and four others which depicted different female faces, was
presented repeatedly on a computer display. Subjects responded by pressing a
button following the landscape picture (target stimulus) that was presented last
in the sequence. In the guilty condition, the procedures were the same except
that subjects were also required not to detect one of the female pictures in mind
(critical item), which they had chosen after the completion of the innocent
condition. As compared with the innocent condition, the CNV amplitudes decreased
significantly immediately before the target stimulus in the guilty condition
where subjects had to conceal the critical item. The implication of these data
both for the psychological completion of the concealed task and the practice in
the field were discussed.
PMID- 9755473
TI - Comparison of proteolytic enzyme activities in adults of insecticide resistant
and susceptible strains of the housefly M. domestica L.
AB - Intracellular proteolytic activity in a DDT-resistant and a susceptible strain of
M. domestica was determined by assaying a comprehensive range of cytoplasmic and
lysosomal enzymes. The resistant strain showed significantly higher protease
activities in whole body, head, thorax, abdomen and gut homogenates compared to
the susceptible strain. The activity of alanyl- and arginyl aminopeptidase from
both strains increased substantially after topical treatment with DDT at 1, 2 and
3 h, suggesting an involvement of proteolytic enzymes in the induction of
detoxifying enzymes, thus indicating a possible role of the intracellular
proteolytic activities in the resistance mechanism.
PMID- 9755474
TI - Isolation, sequence determination, physical and physiological characterization of
the neuroparsins and ovary maturing parsins of Schistocerca gregaria.
AB - Neurosecretory products immunologically related to either neuroparsin (NP) or
ovary maturing parsin (OMP) of Locusta migratoria (Lom) were purified from the
nervous corpora cardiaca of Schistocerca gregaria (Scg). The determination of
both their molecular masses by mass spectrometry and their sequences by automated
Edman degradation established that they are members of the NP and OMP families
respectively. NP molecules of Schistocerca (Scg NPs) consisted of two major forms
having about the same molecular masses as NPA and NPB of Locusta and 88% primary
structure similarity. They had also the same antidiuretic activity. OMP molecules
of Schistocerca (Scg OMPs) were composed in young adults of four isoforms: two
long isoforms corresponding to Lom OMP, and differing by a tripeptide insertion
(Pro-Ala-Ala) at position 21 and two short isoforms deprived of the 13-residue N
terminal peptide of Lom OMP and differing by the same tripeptide insertion. The
PAA isoforms were observed in low amounts as compared to the other isoforms. In
mature adults, only the two short isoforms were present. The complete sequence of
PAA Scg OMP presents a large degree of sequence homology with Lom OMP (83%). The
mixed Scg OMPs had the same biological effects as Lom OMPs. They induced
precocious occurrence of both ecdysteroids and vitellogenin in the haemolymph and
stimulated oocyte growth.
PMID- 9755476
TI - A cuticular protein from the moulting stages of an insect.
AB - A 22 kDa peptide was purified from prepupal cuticles of 5th instar Calpodes
ethlius caterpillars. It was absent earlier in the stadium and from the egg and
adult, i.e. it is related to cuticle turnover rather than cuticle structure. It
was present at larval and metamorphic moults, showing that it is related to
moulting not just metamorphosis. The cDNA corresponding to the 22 kDa peptide was
isolated by antibody screening of an epidermal cDNA expression library.
Hybridization to Calpodes genomic DNA showed that the gene was present as a
single copy. The deduced amino acid sequence is not like any of the sequences of
cuticular structural proteins that have been published, but has a 47 amino acid
sequence similar to bacteriophage T7 N-acetylmuramoyl-L-alanine amidase (34%
identical, 51% similar). The amino acid sequence, the timing of expression in
development, and the similarity between the substrate of the bacteriophage
amidase and components of insect cuticle, all suggest that the 22 kDa protein may
have a role in cleaving chitin-peptide bonds as a prerequisite for digestion of
the cuticle by chitinases and proteases.
PMID- 9755475
TI - Molecular cloning and heterologous expression of a glutathione S-transferase
involved in insecticide resistance from the diamondback moth, Plutella
xylostella.
AB - Four glutathione S-transferase (GST, EC 2.5.1.18) isozymes have been
characterized in the larvae of the diamondback moth (DBM), Plutella xylostella
L., a cosmopolitan insect pest of crucifiers. This work aimed at cloning and
heterologously expressing the cDNA of DBM GST-3, an isozyme involved in this
insect resistance to some organophosphorus insecticides, and studying the
molecular basis for its increased expression in the resistant strains. Reverse
transcription polymerase chain reaction (RT-PCR) using midgut mRNA from a methyl
parathion resistant MPA strain and degenerate primers complimentary to the N
terminal and internal amino acid sequences of GST-3 generated a 128 bp DNA
product. A clone of 809 bp, obtained by screening a midgut cDNA library of MPA
strain using this PCR product as probe, encoded a protein of 216 amino acids
(calculated Mr 24,083 and pI 8.50). This GST of DBM, PxGST3, shared the highest
(46.3%) amino acid sequence identity, among insects, to MsGST1 of Manduca sexta.
PxGST3 mRNA level was considerably higher in MPA than in susceptible strains, and
Southern blots suggested that gene amplification was probably not involved in the
increased expression of this GST isozyme. Enzymatically active PxGST3 expressed
heterologously in E. coli exhibited similar biochemical and toxicological
properties as GST-3 purified from DBM larvae. It is the first cloned GST with a
well-defined role in insecticide resistance.
PMID- 9755477
TI - A hydrophobic peptide (VAP-peptide) of the silkworm, Bombyx mori: a unique role
for adult activity proposed from gene expression and production at the terminal
phase of metamorphosis.
AB - A unique hydrophobic peptide (VAP-peptide) isolated from male adult heads of the
silkworm, Bombyx mori, has been shown to act as a synergist to the diapause
hormone when administered exogenously. Here, we investigated the true role of the
endogenous VAP-peptide on differentiation and development of adult organs in the
silkworm. By northern blot analyses, the VAP-peptide gene was shown to be
exclusively expressed at the terminal phase of adult development in epithelial
tissues, especially in the wing and the thoracic integument. In situ
hybridization analysis revealed that the gene was highly expressed in the
epidermal cells of the wing vein and the thoracic integument. The stage- and
tissue-dependent gene expression were clearly correlated to the accumulation
profile of VAP-peptide. In the adult thoracic integument, VAP-peptide was
predominantly deposited in the cuticle layer. Affinity chromatography indicated
the ability of VAP-peptide to bind to chitin. Based on its expression patterns,
localization, and chemical properties, VAP-peptide is conceived to be a
structural protein that participates in mechanical strengthening of specific
cuticle structures, supporting their physical requirements in the adult life of
the silkworm.
PMID- 9755478
TI - Upregulation of a 23 kDa small heat shock protein transcript during pupal
diapause in the flesh fly, Sarcophaga, crassipalpis.
AB - A diapause upregulated cDNA clone was isolated from a cDNA library generated from
brain mRNA of diapausing Sarcophaga crassipalpis pupae. The clone hybridized to a
1600 bp transcript on a northern blot. The insert is 823 bp in length, has a
tentative open reading frame of 615 bp, and codes for a 23 kDa protein. The clone
has a high level of identity at the amino acid level with the four small heat
shock proteins of Drosophila melanogaster. Northern analysis revealed no
detectable expression of the transcript in diapause- or nondiapause-programmed
wandering larvae, and only trace expression in nondiapausing pupae. But, the
transcript was highly expressed beginning at the onset of diapause and continuing
throughout diapause. Expression promptly decreased when diapause was terminated.
In nondiapausing individuals the transcript was highly expressed in response to
cold shock or heat shock, but temperature stress did not cause greater expression
in diapausing pupae. The results imply that expression of this small heat shock
protein, a response elicited by temperature stress in nondiapausing individuals,
is a normal component of the diapause syndrome. The upregulation of this gene
during diapause suggests that it plays an essential role during this
overwintering developmental arrest.
PMID- 9755479
TI - Basis for selective action of a synthetic molting hormone agonist, RH-5992 on
lepidopteran insects.
AB - The non-steroidal ecdysone agonist, RH-5992, induces a precocious incomplete molt
in lepidopteran insects but is refractory to insects of other orders. We used two
lepidopteran cell lines, FPMI-CF-203 (CF-203) and IPRI-MD-66 (MD-66) and two
dipteran cell lines, DM-2 and Kc, to investigate the lepidopteran specificity of
RH-5992. The mRNAs for hormone receptor 3 homologues cloned from Drosophila
(DHR3) and Choristoneura (CHR3) are directly induced by 20-hydroxyecdysone (20E)
and serve as suitable markers for studying ecdysone action. Dose response
experiments showed that 10(-7) M 20E induced CHR3 mRNA in CF-203 cell and DHR3
mRNA in DM-2 cells. Concentrations of RH-5992 as low as 10(-10) M induced CHR3
mRNA in CF-203 cells, whereas concentrations as high as 10(-6) M induced only
very low levels of DHR3 mRNA in DM-2 cells. Studies using 14C-RH-5992 revealed
that lepidopteran cell lines (CF-203 and MD-66) retained more of this compound
within the cells than the dipteran cell lines (DM-2 and Kc). The clearance of RH
5992 from DM-2 cells was temperature dependent and was blocked by 10(-5) M
ouabain, an inhibitor of Na+, K(+)-ATPase suggesting that the efflux was due to
active transport.
PMID- 9755480
TI - Osmoregulation and salinity effects on the expression and activity of Na+,K(+)
ATPase in the gills of European sea bass, Dicentrarchus labrax (L.).
AB - The European sea bass, Dicentrarchus labrax, tolerates salinities ranging from
freshwater (FW) to hypersaline conditions. In two experiments, we analysed
changes in plasma ions, muscle water content (MWC), gill Na+,K(+)-ATPase
activity, and alpha-subunit mRNA expression during the course of acclimation from
15 ppt salt water to FW or high salinity seawater (HSSW). In Experiment 1, fish
(6.2 +/- 1.1 g) were acclimated from 15 ppt to either FW, 5, 15, 25, 50, or 60
ppt SW and sampled after 10 days. Gill Na+,K(+)-ATPase activity was stimulated in
FW- and in 50 and 60 ppt SW-groups relative to the 15 ppt control group. In
Experiment 2, subgroups of fish (89 +/- 7 g) were transferred from 15 ppt SW to
FW or 50 ppt SW, and sampled 1, 2, 4, and 10 days later. Plasma osmolality, [Na+]
and [Cl-] decreased in the FW-group and increased in the HSSW-group one day after
transfer and lasting until day 10. This was accompanied by a pronounced increase
in MWC in the FW-group and an insignificant decrease in the HSSW-group. The
plasma [Na+]:[Cl-]-ratio increased markedly in the FW-group and decreased
slightly in the HSSW-group, suggesting acid-base balance disturbances after
transfer. Gill Na+,K(+)-ATPase activity was unchanged in 15 ppt SW but doubled in
FW- and HSSW-groups after transfer. In both groups, this was preceded by a 2- to
5-fold elevation of the gill alpha-subunit Na+,K(+)-ATPase mRNA level. Thus
increased expression of alpha-subunit mRNA is part of the molecular mechanism of
both FW and SW acclimation in sea bass. Gill Na+,K(+)-ATPase Na(+)-, K(+)-, and
ouabain-affinity were similar in fish acclimated to FW, 15 ppt, and HSSW,
suggesting that identical isoforms of the catalytic subunit of the enzyme are
expressed irrespective of salinity.
PMID- 9755481
TI - Partial clone of the gene for AS protein of the lamprey Petromyzon marinus, a
member of the albumin supergene family whose expression is restricted to the
larval and metamorphic phases of the life cycle.
AB - AS was previously found to be a liver-synthesized serum protein that is found in
the larval (ammocoete), metamorphosing, and juvenile individuals during the life
cycle of Petromyzon marinus but not in the sexually mature upstream-migrant
individuals (Filosa et al. [1982] Comp. Biochem. Physiol., 72B:521-530; [1986]
Comp. Biochem. Physiol., 83B:143-149; Ito et al. [1988] J. Exp. Zool., 245:256
263). In the present work, a partial clone for the gene for the AS protein was
isolated from a cDNA expression library made from ammocoete liver. Northern blots
using this clone showed hybridization with mRNA from the intervals of the life
cycle prior to the upstream-migration period but not from the upstream-migration
period itself. The cloned DNA was sequenced and the deduced amino acid sequence
was found to have 40% identity with an albumin (our SDS-1 protein) from the
upstream migrants of P. marinus (Gray and Doolittle, [1992] Protein Sci., 1:289
302), which is homologous to mammalian serum albumin. Thus the lamprey has two
genes, AS and SDS-1, that code for different but similar albumin-like proteins,
which predominate at different phases in its life cycle. It is suggested that AS
protein, because it is present only at the earlier phases of the life cycle and
because its gene is transcribed only during this same period, may be an early
version of the alpha-fetoprotein (AFP) of mammals that is found only in the
embryonic, fetal, and neonatal phase of their life cycle.
PMID- 9755482
TI - Sulfur reduction by human erythrocytes.
AB - Washed human erythrocytes incubated with glucose and S8 and purged with N2
produced H2S at a nearly constant rate of 170 mumol (L cells)-1 min-1, which
continued for several hours. In sealed vials up to 25 mM HS- accumulated. Glucose
caused the fastest H2S production, although either lactate or glycerol could
support slower rates. When glucose was added without S8, anoxic H2S production
nonetheless occurred at about 1.5% of the maximum rate, after 24 hr totaling 0.5
mmol H2S (L cells)-1, suggesting the presence of endogenous reducible sulfur.
Anaerobic conditions were not required, since oxygenated cells produced H2S from
S8 at 80% of the anoxic rate. Using cell lysates, production of H2S occurred
after addition of either glutathione, NADH, or NADPH. The observations suggest
possible physiological roles for H2S as an electron carrier, and are consistent
with an evolutionary relationship between eukaryotic cytoplasm and sulfur
reducing Archaea.
PMID- 9755483
TI - Putative multiadhesive protein from the marine sponge Geodia cydonium: cloning of
the cDNA encoding a fibronectin-, an SRCR-, and a complement control protein
module.
AB - Sponges (Porifera) representing the simplest metazoan phylum so far have been
thought to possess no basal lamina tissue structures. One major extracellular
matrix protein that is also a constitutive glycoprotein of the basal lamina is
fibronectin. It was the aim of the present study to identify the native protein
from the marine sponge Geodia cydonium and to isolate the corresponding cDNA. In
crude extracts from this sponge protein(s) of M(r) of approximately 230 and
approximately 210 kDa could be visualized by Western-blotting using an anti
fibronectin [human] antibody. By PCR cloning from a cDNA library of G. cydonium
we isolated a cDNA comprising one element of fibronectin, the type-III (FN3)
module. The cDNA (2.3 kb long), encoding a 701 amino acid [aa] long putative
"multiadhesive protein" termed MAP_GEOCY, was found to contain (i) a fibronectin
, (ii) a scavenger receptor cysteine-rich [SRCR]-, and (iii) a short consensus
repeat [SCR] module. The 89 aa long fibronectin module comprises the
characteristic topology and conserved aa found in fibronectin type-III (FN3)
elements. The SRCR module (101 aa) features the characteristics of group B SRCR
molecules. The predominant proteins belonging to this group are the mammalian WC1
, M130-, CD6- and CD5 antigens that probably are involved in immunological
reactions. The SCR module (54 aa) shows the characteristics of type III SCR
modules found in complement receptors. Phylogenetic analyses performed with all
three building blocks of the "multiadhesive protein" showed that the respective
sponge modules form independent, possibly basal, lineages in trees that include
the corresponding modules from higher metazoan animals. In summary, these data
demonstrate for the first time that the phylogenetically oldest Metazoa, the
sponges, contain protein modules seen in higher animals in proteins of the
extracellular matrix and in molecules involved in cell-mediated immune reactions
in vertebrates.
PMID- 9755484
TI - Acrosomal status of mouse spermatozoa in the oviductal isthmus.
AB - The principal purpose of this study was to establish the acrosomal status of
mouse spermatozoa stored in the isthmus of the oviduct after natural mating.
Scanning electron microscopy of oviducts fixed about 6 hr before the estimated
ovulation time showed numerous acrosome-intact spermatozoa attached to the
mucosal surface of the oviduct, or trapped in the oviductal crypts. Nevertheless,
an unambiguous assessment of the state of the acrosome requires transmission
electron microscopy. Using this method, it was observed that the acrosome was
intact in the 81% of spermatozoa attached to the mucosal surface but in only 31%
of spermatozoa that were free in the lumen. Most of the free spermatozoa showed
swelling or disruption of the acrosome. This result might indicate that the in
vivo spermatozoon-oviductal mucosa interaction maintains the acrosome intact.
Alternatively, it could mean that only ejaculated spermatozoa with a normal
acrosome can establish such a mucosal relationship.
PMID- 9755485
TI - Precursors of the purine backbone augment the inhibitory action of hypoxanthine
and dibutyryl cAMP on mouse oocyte maturation.
AB - In this study we have tested the hypothesis that precursors of the purine base
backbone--glutamine, glycine, aspartic acid, and formate--promote meiotic arrest
when included in medium containing established meiotic inhibitors and that this
occurs in glucose-dependent fashion. An initial experiment established that in
medium supplemented with 4 mM hypoxanthine and containing no purine precursors,
very little meiotic arrest was maintained in cumulus cell-enclosed oocytes after
17-18 hr (90% germinal vesicle breakdown; GVB). Increasing concentrations of
glucose reduced the maturation percentage such that only 57% had matured at 0.55
mM. The addition of 2 mM glutamine (Gln) alone reduced the maturation percentage
in the absence of glucose (70% GVB), and the further addition of glucose revealed
an additive inhibitory effect between these two supplements. Dose response
experiments with Gln, glycine (Gly), aspartic acid and formate showed that in
medium supplemented with hypoxanthine, very little inhibitory action was observed
in the absence of glucose but that upon addition of this hexose, a dramatic
decrease in maturation percentage was observed in the Gln and Gly groups. Results
of experiments using combinations of precursors showed that when Gln and Gly were
added together, greater augmentation of meiotic arrest maintained by either
hypoxanthine or dibutyryl cAMP was achieved in the presence of glucose than with
either amino acid alone. The addition of purine precursors significantly
increased the extent of purine nucleotide production by oocyte-cumulus cell
complexes, and this was accentuated by glucose. It is concluded that the presence
of purine precursors can augment the meiosis-arresting action of established
meiotic inhibitors in glucose-dependent fashion, and that this is due, at least
in part, to their incorporation into purine nucleotides via the de novo synthetic
pathway.
PMID- 9755486
TI - Purification of the precursors to vitelline envelope proteins from serum of
Sakhalin taimen, Hucho perryi.
AB - High and low molecular weight vitelline envelope-related proteins (hVERP and
lVERP) were purified from serum of vitellogenic female Sakhalin taimen (Hucho
perryi) by a combination of ion-exchange, hydroxylapatite and gel filtration
chromatography. The molecular weight of hVERP was estimated to be 83 kDa by gel
filtration, and 48 kDa and 54 kDa in SDS-PAGE under non-reduced and reduced
conditions, respectively. The molecular weight of lVERP was 56 kDa by gel
filtration, and 42 kDa and 46 kDa on SDS-PAGE (non-reduced and reduced,
respectively). Amino acid composition of hVERP was characterized by high content
of proline (15.9%) and glutamic acid (13.8%). The lVERP had high contents of
glutamic acid (10.8%) and aspartic acid (10.5%). Specific antibodies against
hVERP and against lVERP were prepared by immunizing rabbits. The antiserum to
hVERP stained bands corresponding to 98 kDa and 48 kDa of vitelline envelope (VE)
in SDS-PAGE without reduction, whereas the antiserum to lVERP immunostained 98
kDa and 42 kDa bands. Both specific antibodies recognized the vitelline envelope
of vitellogenic oocytes immunocytochemically. Thus, hVERP and lVERP are
precursors to vitelline envelope proteins in this species.
PMID- 9755487
TI - Interaction of the copper(II) macrocyclic complexes with DNA studied by
fluorescence quenching of ethidium.
AB - The fluorescence quenching of DNA bound ethidium ion by copper(II) macrocyclic
complexes has been investigated. The binding constant indicates that the stable
assembly can be formed between the DNA and the metal complex. The replacement of
the fluorophore by the metal complexes results in a decrease of the ethidium
moles intercalating to the molar DNA base pair and the binding constant of the
ethidium to the DNA. The quenching of the ethidium excited state by the Cu(II)
complex follows linear Stern-Volmer behavior. The quenching constant decreases
regularly with an increase of the ratio of the concentration of the bound
ethidium to that of DNA base pair. The dependence of the quenching constant on
the ratio can be used to estimate binding constants for the fluorescent molecule
and metal complexes to DNA. This method does not depend strongly on the type and
the extent of interaction of metal complexes with DNA, allowing for the
determination of binding constants for metal complexes that exhibit small changes
in absorption spectra upon binding. The precision of this method will ultimately
be governed by outstanding agreement between the quenching constant measured and
that calculated by using a correlation function of the ratio or the DNA bound
concentration of ethidium with quenching constant.
PMID- 9755488
TI - Bis(acetato)bis(1-methyl-4,5-diphenylimidazole)copper(II): preparation,
characterization, crystal structure, DNA strand breakage and cytogenetic effect.
AB - The preparation, characterization and antitumour properties of the complex
[Cu(O2CMe)2L2] (1), where L = 1-methyl-4,5-diphenylimidazole, are described. The
crystal structure of 1 (triclinic, space group P1, a = 6.743(1), b = 8.006(1), c
= 15.898(1) A, alpha = 102.87(1), beta = 101.10(1), gamma = 76.76(1) degree, Z =
1) has been determined (R = 0.0254, Rw = 0.0275). In the centrosymmetric complex
the copper ion is in an essentially square planar environment consisting of two
pyridine-type imidazole nitrogen atoms and an oxygen atom from each acetate
ligand; the second oxygen atoms of the carboxylate functionalities are involved
in weak interactions with the metal completing the coordination to a very
distorted tetragonal bipyramid. Complex 1 has been also characterized by
elemental analyses, thermal methods, variable-temperature magnetic susceptibility
and spectroscopic (IR and far-IR, FT-Raman, UV/VIS, EPR) techniques. The effect
of the complex on the in vitro DNA strand breakage was examined. It was found
that 1 causes degradation on the linearized pKS DNA, ds and ss DNA. High
concentrations of this Cu(II) complex cause scissions on the relaxed and the
supercoiled DNA. Furthermore, the in vivo cytogenic effect of 1 was examined on
human lymphocyte cells. This study presents indications that 1 could have some
relevance in the treatment of tumour cell lines. An orbital interpretation of the
interaction of 1 with the DNA bases is proposed.
PMID- 9755489
TI - Synthesis, characterization, and antitumor activity of new platinum(IV) trans
carboxylate complexes: crystal structure of [Pt(cis-1,4-DACH)trans
(acetate)2Cl2].
AB - A series of novel platinum(IV) cisplatin analogues of the type [Pt(cis-1,4
DACH)trans-(L)2Cl2] (where cis-1,4-DACH = cis-1,4-diaminocyclohexane and L =
acetate, propionate, butyrate, valerate, hexanoate, heptanoate, octanoate,
nonanoate, or decanoate) was synthesized and characterized by elemental analysis,
IR, 13C-NMR, and 195Pt-NMR spectroscopy. The structure of [Pt(cis-1,4-DACH)trans
(acetate)2Cl2] (1) was determined by X-ray crystallography. The crystals were
monoclinic, space group P2(1)/n (no. 14) with a = 10.193(2), b = 10.687(2), c =
14.265(3) A, beta = 99.67(3) degrees, Z = 4. The total reflections collected were
2556. The structure refinement converged to R1 = 0.0539 and wR2 = 0.1531. In this
complex, platinum has distorted octahedral geometry, and cis-1,4-DACH is in a
unique twist-boat configuration. cis-1,4-DACH forms a seven-member chelating ring
with platinum, leading to considerable strain in bidentate DACH binding. The
strain is evidenced by a large 126.5(9) degrees C-N-Pt angle. The N-Pt-N angle is
expanded to 97.4(5) degrees owing to geometric constraints of the cis-1,4-DACH
geometry. Three lower homologs of the cis-1,4-DACH-Pt(IV) series were tested in
the murine L1210/0 leukemia model for antitumor activity. The results indicate
that activity decreases in ascending the homologous series, and that the activity
of two of the complexes is substantially better than that of cisplatin with
respect to increase in life span and cures.
PMID- 9755490
TI - Stabilization of the T-state of ferrous human adult and fetal hemoglobin by
Ln(III) complexes: a thermodynamic study.
AB - The effect of the lanthanide(III) complexes [Gd(1,4,7,10-tetraazacyclododecane
N,N',N", N"'-tetrakis(methylenephosphonate))]5- (Gd-DOTP) and La-DOTP on the
oxygen binding and spectroscopic properties of human adult and fetal hemoglobin
(HbA and HbF, respectively) has been investigated. The affinity of Gd-DOTP and La
DOTP for oxygenated HbA (HbAO2; KHbAO2 = 2.6 x 10(-3) M) is closely similar to
that observed for Ln(III) complexes association to nitrosylated HbA (HbANO KHbANO
= 1.8 x 10(-3) M) and to aquo-met HbA (met-HbA; Kmet-HbA = 1.9 x 10(-3) M), being
lower than that determined for Gd-DOTP and La-DOTP binding to the deoxygenated
form of the tetramer (HbAd; KHbAd = 3.0 x 10(-4) M). The affinity of Gd-DOTP for
deoxygenated HbF (HbFd; KHbFd = 9.5 x 10(-4) M) and oxygenated HbF (HbFO2; KHbFO2
= 3.7 x 10(-3) M) is lower than that observed for Ln(III) complexes association
to HbAd and HbAO2, respectively. Gd-DOTP and La-DOTP bind to HbA and HbF with a
1:1 stoichiometry per tetramer. Increasing Gd-DOTP and La-DOTP concentration,
oxygen affinity for HbA decreases (i.e. P50 increases), this effect being minor
for HbF. Upon binding of Ln(III) complexes to HbANO, the X-band EPR spectrum and
the absorption spectrum in the Soret region display the characteristics which
have been attributed to the T-state of the ligated tetramer. These results
represent a clear cut evidence for the specific binding of Gd-DOTP and La-DOTP to
the 2,3-D-glycerate bisphosphate (BPG) pocket (i.e. at the dyad axis, in between
the beta-chains) of HbA and HbF. The effect of Ln(III) complexes on the ligand
binding and spectroscopic properties of HbA and HbF is reminiscent that of BPG,
the physiological modulator of human Hb action.
PMID- 9755491
TI - Solution studies of the antitumor complex dichloro 1,2
propylendiaminetetraacetate ruthenium (III) and of its interactions with
proteins.
AB - A mixed complex of ruthenium (III) with 1,2-propylendiaminetetraacetate (PDTA)
and chloride--RAP hereafter--has been found to exhibit favorable anticancer
properties in vivo. To get some insight into the possible mechanism of action of
this ruthenium (III) complex, its solution behavior and reactivity with proteins
were investigated through absorption, circular dichroism and 1H NMR
spectroscopies. Under physiological conditions RAP slowly looses the two
coordinated chlorine atoms to produce a number of ruthenium (III) reactive
species; a description of the distribution of these species on the dependence of
pH has been obtained through 1H NMR studies of the hyperfine shifted signals.
Remarkably, through the different solution conditions employed in this study, the
ruthenium ion always remains in the 3+ oxidation state and the PDTA ligand is
always bound to the metal. Upon reaction with albumin, apotransferrin or diferric
transferrin, at a 1:1 ratio, RAP rapidly binds to these proteins to produce
substantially equivalent and relatively stable adducts. This behavior is
tentatively interpreted in terms of a tight interaction between RAP and surface
residues of these proteins. The implications of these findings for the biological
action of this novel ruthenium (III) compound are discussed.
PMID- 9755492
TI - Antibacterial tests of bismuth(III)-quinolone (ciprofloxacin, cf) compounds
against Helicobacter pylori and some other bacteria. Crystal structure of
(cfH2)2[Bi2Cl10].4H2O.
AB - The antibacterial tests of two bismuth(III)-ciprofloxacin (cf) compounds against
Helicobacter pylori (H. pylori) and some other bacteria were performed. The
results have shown that the activity of both compounds is comparable to that of
ciprofloxacin hydrochloride. The crystal structure of (cfH2)2[Bi2Cl10].4H2O (cfH2
= doubly protonated molecule of cf) is presented and discussed. The compound was
isolated from acidic medium where quinolone is protonated and thus no bonding
between quinolone and bismuth was observed. The bismuth(III) ions are coordinated
by chloride ions forming dinuclear [Bi2Cl10]4- anions. The charge of this ion is
compensated with protonated quinolone molecules (ionic interactions).
PMID- 9755493
TI - The bidirectional effect of vanadyl ion on the oxygen affinity of human
hemoglobin.
AB - The bidirectional effects of vanadyl on the oxygen affinity of hemoglobin depend
on the mole ratio of vanadyl to Hb(R). In low R, the vanadyl ion increases Hb's
oxygen affinity due to DPG hydrolysis. The lowered oxygen affinity in higher R is
mainly due to the reactive-oxygen-species, probably superoxide, induced oxidation
of Fe(II)-Hb to Fe(III)-Hb. The conformation change due to vanadyl binding
contribute also to the lowered oxygen binding, but is monotonously decreasing
with increasing of R values.
PMID- 9755494
TI - Complexation of type 2 copper by cytochrome c oxidase: probing of metal-specific
binding sites by electron paramagnetic resonance.
AB - Cytochrome c oxidase, CcO, contains at least four, probably five type 2 copper
binding sites per monomer in addition to the mixed valence [CuA(1.5+)CuA(1.5+)],
S = 1/2 center and the EPR-silent CuB. Electron paramagnetic resonance (EPR)
parameters for these site are g parallel = 2.22 and A parallel = 195 G. Nitrogen
superhyperfine structure is observed in the g perpendicular region, with A
perpendicular N of around 15 G. The EPR parameters for Cu(2+) bound to a
synthetic peptide, AHGSVVKSEDYALPS, are similar to the parameters for the type 2
sites in CcO. The lines in the EPR spectrum of the type 2 site in the synthetic
peptide are better resolved at low microwave frequency (3.4 GHz). Resolved lines
in the expansion of the MI = -1/2 line in the g parallel region of the low
frequency spectrum are attributed to superhyperfine structure from three almost
equivalent nitrogen donor atoms bound to Cu(2+) in a square planar configuration.
The MI = -1/2 line in the g parallel region for excess Cu(2+) bound to CcO is not
as well resolved as for the synthetic peptide, presumably because the four or
five binding sites per monomer are similar, but not exactly equivalent. These
binding sites are proposed to be at the N-terminus of subunits of CcO, for
example, at subunit IV where the sequence is AHGS-. Nitrogen donor atoms from the
alpha-amino group of the amino terminal residue, the imidazole group of
histidine, and a peptide nitrogen are predicted to comprise the binding site.
PMID- 9755495
TI - A quantitative method for analysing AFM images of the outer surfaces of human
hair.
AB - Cuticle step height is an important parameter for the quantitative assessment of
human hair. This paper describes a novel, computational method for the rapid
calculation of step heights from atomic force microscope images obtained from
large numbers of specimens. Such an approach is necessary to allow a statistical
analysis of the inherently wide distribution of cuticle step heights
characteristic of a single hair sample. The method described will be of use to
cosmetic formulation chemists and forensic scientists and also to dermatologists
in the field of disease diagnosis.
PMID- 9755496
TI - Neurofilament-L homopolymers are less mechanically stable than native
neurofilaments.
AB - Neurofilaments are cytoskeletal components of neurones that are thought to play
an important structural role in the axon. Specific functions of neurofilaments
are not yet well defined; however, other intermediate filaments are known to have
structural and mechanical functions in different cell types. The atomic force
microscope (AFM) can be used to visualize and manipulate biological structures
through direct physical contact. This allows the AFM to be used to probe the
mechanical properties of these structures. In this paper we present AFM images of
native neurofilaments isolated from bovine spinal cord, composed of NF-L, NF-M
and NF-H, and filaments polymerized in vitro from purified NF-L. Morphologically
these structures, in solution and under ambient conditions, are in agreement with
previous data from electron microscopy. However, repeated scanning of NF-L
homopolymers (in solution) produced significant disruptions of segments of
filaments, both within and at the ends of the filaments. This disruption resulted
in complete loss of portions of the filaments and in breaks in the continuity of
the filaments. Repeated scanning of isolated native neurofilaments under similar
conditions produced no detectable structural changes. Under extremely high
applied forces the native neurofilaments were bent and distorted by the action of
the AFM tip, but were never broken. These data suggest that purified NF-L is not
sufficient to confer complete mechanical stability to neurofilaments.
PMID- 9755497
TI - Star length distribution: a volume-based concept for the characterization of
structural anisotropy.
AB - Determination and quantification of anisotropy is of great interest in research
fields dealing with physical structures or surface textures. In this paper, a
volume-based method is presented, which essentially determines the mean object
length in a certain direction for a typical point within a structure or texture.
The mean object lengths for all orientations together form the so-called star
length distribution (SLD). The validity and the accuracy of the SLD method are
investigated, and illustrated by applying it to trabecular bone. By using a line
sampling algorithm, the relation with other anisotropy measures could be studied
analytically. Preliminary tests suggest that with SLD a more exact description of
the mechanical properties of porous structures may be obtained than with other
anisotropy measures. However, due to possible secondary orientations that become
apparent with SLD, a fabric tensor must be of rank higher than two in order to
properly describe an orthogonal structure mathematically.
PMID- 9755498
TI - X-ray microanalysis of native airway surface liquid collected by cryotechnique.
AB - The airway surface liquid (ASL) that lines the surface epithelium of the
tracheobronchial tree is of vital importance to the airway defence against
microbial invasion and damage due to environmental factors. Little is known about
the ASL collected in situ in native conditions, owing to difficulties in
collecting ASL without causing damage to the airway mucosa. We have developed a
method to collect and analyse the elemental composition of tracheal ASL in
pathogen-free mice. A specially designed cryoprobe, adapted to the internal
curvature of the mouse trachea, was used to collect the native ASL from the
tracheal surface. The complete ASL elemental composition including [Na] = 5.5 +/-
0.3, [Cl] = 1.3 +/- 0.3, [K] = 1.1 +/- 0.2, [Ca] = 1.2 +/- 0.3, [P] = 1.5 +/-
0.8, [S] = 1.7 +/- 0.4 and [Mg] = 1.3 +/- 0.4 mmol L-1 was determined by X-ray
micro-analysis. We demonstrate here that the technique that we used for ASL
collection maintained perfectly the airway epithelial integrity and
functionality.
PMID- 9755499
TI - Cryo-TEM liquid nitrogen splash guard.
PMID- 9755500
TI - Determination of calcium binding sites in gas-phase small peptides by tandem mass
spectrometry.
AB - Low-energy (LE) and high-energy (HE) collisionally activated decompositions (CAD)
of calcium/peptide complexes of the form [M - H + Ca]+ and [M + Ca]2+ reflect the
site of calcium binding in various gas-phase peptides that are models of the
calcium binding site III of rabbit skeletal troponin C. The Ca2+ binding sites
involve an aspartic acid, glutamic acid, and asparagine, which are in the metal
binding loops of calcium-binding proteins. Both fast atom bombardment (FAB) and
electrospray ionization (ESI) were used to generate the metal/peptide complexes.
When submitted to LE CAD, ESI-produced Ca2+/peptide complexes undergo
fragmentations that are controlled by Ca2+ binding and provide information on the
Ca2+ binding site. The LE CAD spectra are simple, indicating that Ca2+ binding
involves specific oxygen ligands including acidic side chains and that only a few
low-energy fragmentation channels exist. The HE CAD spectra of FAB-produced
Ca2+/peptide complexes are more complex, owing to the introduction of high
internal energy into the precursor ion. Interactions of the other alkaline-earth
metal ions Mg2+ and Ba2+ with these peptides reveal that the ligand preferences
of these metal ions are slightly different than those of Ca2+.
PMID- 9755501
TI - Analysis of peptides, proteins, protein digests, and whole human blood by
capillary electrophoresis/electrospray ionization-mass spectrometry using an in
capillary electrode sheathless interface.
AB - An in-capillary electrode sheathless interface was applied to the capillary
electrophoresis/electrospray ionization-mass spectrometry (CE/ESI-MS) analysis of
mixtures of small peptides, proteins, and tryptic digests of proteins. The
effects of different experimental parameters on the performance of this CE/ESI-MS
interface were studied. The distance of the in-capillary electrode from the CE
outlet and the length of the electrode inside the capillary had no significant
effects on the CE separation and ESI behavior under the experimental conditions
used. However, significant enhancement of the sensitivity resulted from the use
of narrower CE capillaries. Using a quadrupole mass spectrometer, an
aminopropylsilane-coated capillary, and a wide scan mass-to-charge ratio range of
500-1400, detection limits of approximately 4, 1, and 0.6 fmol for cytochrome c
and myoglobin were achieved for 75-, 50-, and 30-micron inner diameter
capillaries, respectively. Approximately one order of magnitude lower detection
limits were achieved under the multiple-ion monitoring mode. The application of
the in-capillary electrode sheathless interface to real-world samples was
demonstrated by CE/ESI-MS analysis of a human blood sample.
PMID- 9755502
TI - Antimicrobial susceptibilities of strains of Nocardia brasiliensis isolated from
soil of Tucuman.
AB - The activity of antimicrobial agents against soil isolates of N. brasiliensis was
studied by determination of the minimum inhibitory concentrations (MICs) and disk
diffusion technique, according to the National Committee for Clinical Laboratory
Standards (NCCLS). The objectives were: (a) to study the patterns of sensitivity
among regional strains of N. brasiliensis isolated from natural sources (soil) of
different zones of Tucuman province; (b) to correlate these results with those
previously obtained with regional strains of N. brasiliensis isolated from human
mycetomas, as a contribution in the evaluation of the importance of the natural
reservoir area of the potentially pathogen strains. The results obtained by both
methods identified strains of N. brasiliensis from soils with similar patterns of
susceptibility to the strains N. brasiliensis isolated from human mycetomas. This
showed strains sensitive and resistant to antibiotics. The majority of the
isolates of N. brasiliensis from soils showed higher susceptibilities to
antibiotics than the strains isolated from human mycetomas. Among the antibiotics
studied, cefotaxime, ceftriaxone and gentamicin were the most effective against
all the regional strains tested, and these results are correlated with those
obtained with regional strains that cause human mycetomas.
PMID- 9755503
TI - Cutaneous Pythiosis insidiosi in calves from the Pantanal region of Brazil.
AB - Two cases of cutaneous Pythiosis insidiosi were diagnosed in cattle from the
Pantanal region, Brazil. The lesions were observed in the limbs of two 8-month
old beef calves. Close examination showed local swelling and focal ulceration of
the skin. Microscopically, there was multifocal granulomatous dermatitis with
intralesional Pythium insidivosum hyphae. The diagnosis was based on the
morphological aspects, immunohistochemical findings and culture of the etiologic
agent.
PMID- 9755504
TI - Isolation of a petite mutant from a histidine auxotroph of Candida albicans and
its characterization.
AB - Respiration-deficient (petite) mutations have been induced in various yeasts,
which are categorized as petite-positive. Candida albicans was classified among
the petite-negative yeasts. Since then, a few reports have appeared, describing
the isolation of petite mutants in C. albicans. We report in the present study on
the isolation of a petite mutant of C. albicans-SAR1. This mutant was isolated
from a histidine auxotroph of C. albicans after mutagenesis with N-methyl-N'
nitro-N-nitrosoguanidine, thus our petite mutant carries a double mutation. SAR1
was characterized morphologically, biochemically and ultrastructurally. The
results revealed differences from the wild type in respect to morphological,
physiological and biochemical characteristics. Electron microscopy showed that
the cells of the petite mutant contain only very few mitochondria that looked
'thread like' without any cristae. The significance of the mutation in the
virulence of the mutant vs. that of the wild-type is being assessed.
PMID- 9755505
TI - Monoclonal antibodies directed against extracellular matrix proteins reduce the
adherence of Candida albicans to HEp-2 cells.
AB - The presence of the extracellular matrix (ECM) proteins collagen types I and IV,
laminin and fibronectin on the surface of HEp-2 cells was confirmed by flow
cytometry using monoclonal antibodies. Monoclonal antibodies directed against
these ECM proteins reduced the adherence of C. albicans ATCC 44990 to HEp-2
cells, the greatest reductions being evident in assays which incorporated anti
collagen type IV monoclonal antibody. The ability of sugaramines to inhibit the
adherence of C. albicans to a variety of cell types has been demonstrated
previously and the most significant reduction in C. albicans-HEp-2 adherence was
in assays which incorporated 0.2M galactosamine. The combination of anti-collagen
IV monoclonal antibody and galactosamine reduced the adherence of C. albicans to
HEp-2 cells by approximately 70% (p < 0.05).
PMID- 9755506
TI - Experimental penetration of Trichophyton mentagrophytes into human stratum
corneum.
AB - We present confirmation of the experimental penetration of Trichophyton
mentagrophytes into human stratum corneum under designated conditions of
temperature and humidity. When stratum corneum, obtained from healthy human heel
region, was incubated at 100% humidity, mycelium was observed in the corneum
layer on day 2 at 35 degrees C and 27 degrees C, and on day 4 at 15 degrees C. At
90% humidity, the hyphae penetrated into the stratum corneum on day 4 at 35
degrees C, and on day 6 at 27 degrees C. Whereas, at 80% humidity, no fungal
elements were observed in the stratum corneum at both 27 degrees C and 35 degrees
C for up to 7 days. These data suggested that humidity was a more important
environmental factor for penetration than temperature, and that at least 90%
humidity is necessary for dermatophytes to penetrate into the stratum corneum
within a few days. Mean humidity in the interdigital space between the fourth and
fifth toes was found to be approximately 98%.
PMID- 9755507
TI - Comparing properties of brains and computers.
AB - The criterion that pure natural science can only investigate objective phenomena
which can be observed by independent observers sets certain limits to pure
natural scientific understanding of brain functions. It excludes consciousness
and feelings since these are only subjectively accessible and alternatives cannot
be decided objectively. The limitations of brain research are discussed by
comparing the properties of brains and computers. At least for the time being we
do not know of any natural scientific--i.e. physical or chemical--method which
allows the objective measurement of consciousness, sensations, and emotions. In
addition it is discussed how and in how far our brain understands its surrounding
nature.
PMID- 9755508
TI - Representation in natural and artificial agents: an embodied cognitive science
perspective.
AB - The goal of the present paper is to provide an embodied cognitive science view on
representation. Using the fundamental task of category learning, we will
demonstrate that this perspective enables us to shed new light on many pertinent
issues and opens up new prospects for investigation. The main focus of this paper
is on the prerequisites to acquire representations of objects in the real world.
We suggest that the main prerequisite is embodiment which allows an agent--human,
animal or robot--to manipulate its sensory input such that invariances are
generated. These invariances, in turn, are the basis of representation formation.
In other words, the paper does not focus on representations per se, but rather
discusses the various processes involved in order to make learning and
representation acquisition possible. The argument structure is as follows. First
we introduce two new perspectives on representation, namely frame-of-reference,
and complete agent. Then we elaborate the complete agent perspective and focus in
particular on embodiment and situatedness. We argue that embodiment has two main
aspects, a dynamic and an information theoretic one. Focusing on the latter,
there are a number of implications: Representation can only be understood if the
embedding of the neural substrate in the physical agent is known, which includes
morphology (shape), positioning and nature of sensors. Because an autonomous
mobile agent in the real world is exposed to a continuously changing high
dimensional stream of sensory stimulation, if it is to learn category
distinctions, it first needs a focus of attention mechanism, and then it must
have a way to reduce the dimensionality of this high-dimensional sensory stream.
Learning is very hard because the invariances are typically not found in the
sensory data directly--the classical problem of object constancy: it is a so
called type 2 problem. Rather than trying to improve the learning algorithms-
which is the standard approach--the embodied cognitive science view suggests a
different approach which focuses on the nature of the data: the agent is not
passively exposed to a given data distribution, but, by exploiting its body and
through the interaction with the environment, it can actually generate the data.
More specifically, it can generate correlated data that has the property that it
can be easily learned. This learnability is due to redundancies resulting from
the appropriate interactions with the environment. Through such interactions, the
former type 2 problem is transformed into a type 1 problem, thus reducing the
complexity of the learning task by orders of magnitude. By observing the frame-of
reference problem we will discuss to what extent these invariances are reflected-
represented--in the "neural substrate", i.e. the internal mechanisms of the
agent. It is concluded, that representation is not a concept that can be studied
in the abstract, but should be elaborated in the context of concrete agent
environment interactions. These ideas are all illustrated with examples of
natural agents and artificial agents. In particular, we will present a suite of
experiments on simulated and real-world artificial agents instantiating the main
arguments.
PMID- 9755509
TI - The representation of space and the hippocampus in rats, robots and humans.
AB - Experimental evidence suggests that the hippocampus represents locations within
an allocentric representation of space. The environmental inputs that underlie
the rat's representation of its own location within an environment (in the firing
of place cells) are the distances to walls, and different walls are identified by
their allocentric direction from the rat. We propose that the locations of goals
in an environment is stored downstream of the place cells, in the subiculum. In
addition to firing rate coding, place cells may use phase coding relative to the
theta rhythm of the EEG. In some circumstances path integration may be used, in
addition to environmental information, as an input to the hippocampal system. A
detailed computational model of the hippocampus successfully guides the
navigation of a mobile robot. The model's behaviour is compared to
electrophysiological and behavioural data in rats, and implications for the role
of the hippocampus in primates are explored.
PMID- 9755510
TI - Modular organization of motor behavior.
AB - The issue of translating the planning of arm movements into muscle forces is
discussed in relation to the recent discovery of structures in the spinal cord.
These structures contain circuitry that, when activated, produce precisely
balanced contractions in groups of muscles. These synergistic contractions
generate forces that direct the limb toward an equilibrium point in space.
Remarkably, the force outputs, produced by activating different spinal-cord
structures, sum vectorially. This vectorial combination of motor outputs might be
a mechanism for producing a vast repertoire of motor behaviors in a simple
manner.
PMID- 9755511
TI - Visual recognition based on temporal cortex cells: viewer-centred processing of
pattern configuration.
AB - A model of recognition is described based on cell properties in the ventral
cortical stream of visual processing in the primate brain. At a critical
intermediate stage in this system, 'Elaborate' feature sensitive cells respond
selectively to visual features in a way that depends on size (+/- 1 octave),
orientation (+/- 45 degrees) but does not depend on position within central
vision (+/- 5 degrees). These features are simple conjunctions of 2-D elements
(e.g. a horizontal dark area above a dark smoothly convex area). They can arise
either as elements of an object's surface pattern or as a 3-D component bounded
by an object's external contour. By requiring a combination of several such
features without regard to their position within the central region of the visual
image, 'Pattern' sensitive cells at higher levels can exhibit selectivity for
complex configurations that typify objects seen under particular viewing
conditions. Given that input features to such Pattern sensitive cells are
specified in approximate size and orientation, initial cellular 'representations'
of the visual appearance of object type (or object example) are also selective
for orientation and size. At this level, sensitivity to object view (+/- 60
degrees) arises because visual features disappear as objects are rotated in
perspective. Processing is thus viewer-centred and the neurones only respond to
objects seen from particular viewing conditions or 'object instances'. Combined
sensitivity to multiple features (conjunctions of elements) independent of their
position, establishes selectivity for the configurations of object parts (from
one view) because rearranged configurations of the same parts yield images
lacking some of the 2-D visual features present in the normal configuration.
Different neural populations appear to be selectively tuned to particular
components of the same biological object (e.g. face, eyes, hands, legs), perhaps
because the independent articulation of these components gives rise to correlated
activity in different sets of input visual features. Generalisation over viewing
conditions for a given object can be established by hierarchically pooling
outputs of view-condition specific cells with pooling operations dependent on the
continuity in experience across viewing conditions. Different object parts are
seen together and different views are seen in succession when the observer walks
around the object. The view specific coding that characterises the selectivity of
cells in the temporal lobe can be seen as a natural consequence of selective
experience of objects from particular vantage points. View specific coding for
the face and body also has great utility in understanding complex social signals,
a property that may not be feasible with object-centred processing.
PMID- 9755512
TI - An architecture for distributed visual memory.
AB - The development of autonomous as well as situated robots is one of the great
remaining challenges and involves a number of different scientific disciplines.
In spite of recent dramatic progress, it remains worthwhile to examine natural
systems, because their abilities are still out of reach. Motivated by research
work done in the fields of cognitive systems, visual perception, and psychology
of memory we designed and implemented a memory architecture for visual tasks.
Structural and functional concepts of the memory architecture were modeled on the
ones found in natural systems. We present an efficient implementation based on
parallel programming techniques. The memory module is integrated into a
distributed system for speech and image analysis, which is currently developed in
the Sonderforschungsbereich (SFB) 360, Situated Artificial Communicators, where a
hybrid vision system combining neural and semantic networks is used.
PMID- 9755513
TI - How can adaptive behavioural plasticity be implemented in the mammalian brain?
AB - The adaptive control of behaviour requires brain mechanisms for the selection
(i.e. activation and suppression) of responses, as well as mechanisms for the
modulation of the response vigour. The concept of motivation postulates the
existence of brain centres that regulate the selection and strength of
behavioural responses. The present paper provides examples from the behavioural
neurosciences for brain mechanisms that lead to adaptive changes of an organisms
responsiveness to external stimuli. The mammalian startle response is a simple
defensive behaviour which is mediated by an oligosynaptic pathway located in the
lower brainstem. The startle response is enhanced by aversive states (fear,
anxiety) and attenuated by appetitive states (pleasure), which can be regarded as
an example of motivational priming. Furthermore, the startle response is
inhibited by a weak sensory stimulus presented shortly before the startling
stimulus. The suppression of startle by a prepulse is an example of sensorimotor
gating, a principle that is important for the hierarchical organisation of
behaviour. This paper describes the neuronal mechanisms underlying the modulation
(prepulse inhibition and fear potentiation) of the startle response in rats, and
discusses the possible adaptive significance of these different phenomena of
behavioural plasticity.
PMID- 9755515
TI - Motion segmentation in artificial and biological system.
AB - In the early steps of visual information processing motion is one of the most
important queues for the development of spatial representations. Obstacle
detection and egomotion estimation are only two examples of the powerfulness of
visual motion detection systems. The underlying process of information extraction
has to be active due to the observer's capabilities of egomotion. This means that
the observer's motion has an impact on the projected retinal motion field.
Therefore one of the challenging tasks for biological as well as for technical
vision systems is to couple retinal motion and egomotion and to uncouple
egomotion and object motion. The following sections describe a model that couples
visual motion processing with the egomotion parameters of a moving observer.
Beneath a theoretical introduction of the model an application to traffic scene
analysis is presented. At last the paper relates the model to biological motion
processing systems.
PMID- 9755514
TI - How it is to be the brain of a monkey.
AB - Hypotheses are presented on neural peculiarities of the monkey brain that
distinguish monkeys from other mammals and man: The unique feature of cortical
tissue is that it can be applied serially. It fulfils some requirements of a
powerful visual system. The richness of visual as compared to other signals has
yielded a basis for recognizing the bodily similarity of oneself to conspecifics.
A visuo/motor coupling trained on oneself but applied to conspecifics ("aping")
evolved. Long series of (generalized visuo/visual) computations feasible in a
very large cortex would produce excessive delays that would not correspond to
outer world delays. The new human solution to this is an "offline" system in
which temporal relationships are described by excitation patterns. This gives
rise to a rapid expansion of the cortex. In humans, a "meaning" has to be
attributed to the mutual (computational) relationships of excitation patterns in
the offline system, by a reference to the corresponding relationships that would
be valid in the normal (online) system. "Perception" is a corollary of this. The
offline treatment of time, together with "aping", leads to new types of helping
and other social interactions. Monkeys may be compared to humans not using their
offline system in the state of "absent-mindedness". Experimental approaches
departing from excitation patterns are discussed.
PMID- 9755517
TI - Emergence of spatio-temporal patterns in neuronal activity.
AB - This paper explores if dynamic modulation of coherent firing serves cortical
functions. We recorded neuronal activity in the frontal cortex of behaving
monkeys and found that temporal coincidences of spikes firing of different
neurons can emerge within a fraction of a second in relation to the animal
behavior. The temporal patterns of the correlation could not be predicted from
the modulations of the neurons firing rate and finally, the patterns of
correlation depend on the distance between neurons. These findings call for a
revision of prevailing models of neural coding that solely rely on firing rates.
The findings suggest that modification of neuronal interactions can serve as a
mechanism by which neurons associate rapidly into a functional group in order to
perform a specific computational task. Increased correlation between members of
the groups, and decreased or negative correlation with others, enhance the
ability to dissociate one group from concurrently activated competing groups.
Such modulation of neuronal interactions allows each neuron to become a member of
several different groups and participate in different computational tasks.
PMID- 9755518
TI - Cellular dynamics of network memory.
AB - One example of "emergence" is the development, as a result of neural ontogeny and
living experience, of cortical networks capable of representing and retaining
cognitive information. A large body of evidence from neuropsychology,
electrophysiology and neuroimaging indicates that so-called working memory and
long-term memory share the same neural substrate in the cerebral cortex. That
substrate consists in a system of widespread, overlapping and hierarchically
organized networks of cortical neurons. In this system, any neuron or group of
neurons can be part of many networks, and thus many memories. Working memory is
the temporary activation of one such network of long-term memory for the purpose
of executing an action in the near future. The activation of the network may be
brought about by stimuli that by virtue of prior experience are in some manner
associated with the cognitive content of the network, including the response of
the organism to those stimuli. The mechanisms by which the network stays
activated are presumed to include the recurrent re-entry of impulses through
associated neuronal assemblies of the network. Consistent with this notion is the
following evidence: (1) working memory depends on the functional integrity of
cortico-cortical connective loops; and (2) during working memory, remarkable
similarities--including "attractor behavior"--have been observed between firing
patterns in real cortex and in an artificial recurrent network.
PMID- 9755516
TI - Simulation of complex movements using artificial neural networks.
AB - A simulated network for controlling a six-legged, insect-like walking system is
proposed. The network contains internal recurrent connections, but important
recurrent connections utilize the loop through the environment. This approach
leads to a subnet for controlling the three joints of a leg during its swing
which is arguably the simplest possible solution. The task for the stance subnet
appears more difficult because the movements of a larger and varying number of
joints (9-18: three for each leg in stance) have to be controlled such that each
leg contributes efficiently to support and propulsion and legs do not work at
cross purposes. Already inherently non-linear, this task is further complicated
by four factors: 1) the combination of legs in stance varies continuously. 2)
during curve walking, legs must move at different speeds, 3) on compliant
substrates, the speed of the individual legs may vary unpredictably, and 4) the
geometry of the system may vary through growth and injury or due to non-rigid
suspension of the joints. This task appears to require some kind of "motor
intelligence". We show that an extremely decentralized, simple controller, based
on a combination of negative and positive feedback at the joint level, copes with
all these problems by exploiting the physical properties of the system.
PMID- 9755519
TI - Non-linear mechanisms in the brain.
AB - Non-linear dynamical models of brain activity can describe the spontaneous
emergence of large-scale coherent structures both in a temporal and spatial
domain. We discuss a number of discrete time dynamical neuron models that
illustrate some of the mechanisms involved. Of special interest is the phenomenon
of spatio-temporal stochastic resonance in which coherent structures emerge as a
result of the interaction of the neuronal system with external noise at a given
level punitive data. We then discuss the general role of stochastic noise in
brain dynamics and how similar concepts can be studied in the context of networks
of connected brains on the Internet.
PMID- 9755520
TI - Accurate spike synchronization in cortex.
AB - In view of the enormous capacity and complexity of mammalian brains it is evident
that a detailed account of their anatomy and physiology alone cannot lead to a
complete understanding of their function. Computer simulation and mathematical
analysis of abstract, yet biologically realistic models for neurons and networks
yield additional and useful information about the interplay of the underlying
anatomical structures, the physiological processes operating on the neuronal
substrate, and the resulting brain functions during the performance of behavioral
tasks. We discuss some contributions of such experiment-guided theory to the
issue of accurate spike synchronization.
PMID- 9755521
TI - Solutions for the binding problem.
AB - Visual cortical neurons are broadly tuned to one or a few feature dimensions,
like color and motion. This is advantageous because broadly tuned neurons can
contribute to the representation of many visual scenes. However, if there are
multiple objects in a visual scene, the cortex is at risk to combine features of
different objects as if they belong to a single object. The term "binding
problem" was introduced to refer to the difficulties that may occur in sorting
out those responses that are evoked by a single perceptual object. The present
article reviews proposals suggesting that the binding problem is solved by
labelling an assembly of neurons that is responsive to a single perceptual
object. Evidence is reviewed in favor of two possible assembly-labels: rate
enhancement due to visual attention and neuronal synchrony. Assembly-labels
should be spread through the cortical network to all neurons that have to
participate in an assembly. The present article tries to shed light on the
mechanisms that subserve such a selective spread of assembly labels. Moreover, it
is suggested that assembly labels may fulfill an equivalent role in the motor
system, since binding problems can also occur during the generation of useful
patterns of motor activity.
PMID- 9755522
TI - Networks of gene regulation, neural development and the evolution of general
capabilities, such as human empathy.
AB - A network of gene regulation organized in a hierarchical and combinatorial manner
is crucially involved in the development of the neural network, and has to be
considered one of the main substrates of genetic change in its evolution. Though
qualitative features may emerge by way of the accumulation of rather unspecific
quantitative changes, it is reasonable to assume that at least in some cases
specific combinations of regulatory parts of the genome initiated new directions
of evolution, leading to novel capabilities of the brain. These notions are
applied, in this paper, to the evolution of the capability of cognition-based
human empathy. It is suggested that it has evolved as a secondary effect of the
evolution of strategic thought. Development of strategies depends on abstract
representations of one's own possible future states in one's own brain to allow
assessment of their emotional desirability, but also on the representation and
emotional evaluation of possible states of others, allowing anticipation of their
behaviour. This is best achieved if representations of others are connected to
one's own emotional centres in a manner similar to self-representations. For this
reason, the evolution of the human brain is assumed to have established
representations with such linkages. No group selection is involved, because the
quality of strategic thought affects the fitness of the individual. A secondary
effect of this linkage is that both the actual states and the future perspectives
of others elicit vicarious emotions, which may contribute to the motivations of
altruistic behaviour.
PMID- 9755523
TI - Emergence and the cognitive neuroscience approach to psychiatry.
AB - In this paper, I introduce the philosophical notion of strong emergence and argue
that it is almost exclusively applied to properties related to (conscious)
subjective experience. Contrary to the still common attitude of refraining
anxiously from these topics, I argue that we have a promising scientific approach
to them: the cognitive neurosciences. I list a spectrum of interesting,
potentially strongly emergent properties already investigated, and discuss the
example of volition in more detail. Psychiatric disorders, like antisocial
personality disorder, schizophrenia, and obsessive compulsive disorder, open new
ways for understanding aspects of volition such as willed action, decision
making, and agency. I conclude that the notion of strong emergence is only a
preliminary label which, however, might be understood as a challenge for
empirical scientists to explain and understand phenomena related to subjectivity
and consciousness.
PMID- 9755524
TI - Group report: influence of brain and computer design on the performance of
natural and artificial organisms.
PMID- 9755526
TI - [Current view of the indications for surgical treatment of congenital heart
diseases].
PMID- 9755525
TI - Group report: emergent properties of natural and artificial systems.
PMID- 9755527
TI - [Evidence based cardiology in focus. Solid and robust cardiology practice].
PMID- 9755528
TI - [Evidence based cardiology. I. Principles, rationale and applications of a new
cardiology practice and critical analysis of the literature].
PMID- 9755530
TI - [Cardiovascular diseases observed during follow-up of a group of patients with
undetermined form of Chagas' disease].
AB - PURPOSE: The aim of this study was to evaluate the cardiovascular outcome in
patients with the undetermined form of Chagas' disease and whether or not it is
related to the infectious disease in the long-term. METHODS: One hundred and
sixty patients were prospectively followed-up at three month intervals for up to
177 months. RESULTS: Twenty and three (14.4%) patients developed hypertension
complicated by ischemic stroke in two (1.2%) and symptomatic heart failure in one
(0.6%). Cardiac arrhythmias occurred in four (2.4%) patients corresponding to
isolated ventricular ectopic beats in two (1.2%), isolated supraventricular
ectopic beats in one (0.6%) and an isolated episode of acute atrial fibrillation
in another (0.6%). Two (1.2%) patients developed symptoms of coronary artery
disease, one of them had one episode of acute chest pain diagnosed as myocardial
infarction and the other had chronic chest pain diagnosed as angina. CONCLUSION:
Hypertension is the most common cardiovascular disease occurring in the long-term
follow-up of patients with the undetermined form of Chagas' disease. Cardiac
rhythm disturbances and coronary artery disease were not more frequent than those
generally found in a healthy population. These data confirm a favorable long-term
prognosis in patients with the undetermined form of Chagas' disease.
PMID- 9755529
TI - [Heart failure at a large tertiary hospital of Sao Paulo].
AB - PURPOSE: To study the incidence, main causes, aggravating factors and secondary
diagnoses of heart failure (HF) during 1995 at the Instituto do Coracao of Sao
Paulo. METHODS: Data from hospitalized patients according to the PRODESP data
base were analyzed. The following data were studied; age, sex, principal and
secondary diagnoses, surgical procedures and mortality. To analyze the data,
tables according to sex, age and main cause were built. Analysis of variance and
t test were employed to verify differences between groups. RESULTS: In 1995, 903
out of 9620 patients were hospitalized due to HF. The majority were male (60.4%)
and the patients' age was between two days and 98 years old (mean 52.6). Ischemic
(32.6), dilated (25.8%) and valvar heart disease (22%) were the main causes of
HF. 32.1% were submitted to correction of the HF main cause, specially those with
valvar heart disease (62.3%). There was greater incidence of multiple diagnoses
in aged patients. The mortality was greater in patients younger than 20 and in
those older than 80 years old. CONCLUSION: The incidence of HF at INCOR during
1995 was 9.38%. Ischemic myocardiopathy was the most frequent HF cause. The
mortality was greater among children, probably because of heart disease
complexity and, in the above-80 group due to the greater comorbidity.
PMID- 9755531
TI - [Comparison of coronary arteriosclerosis in patients with myocardial infarction
and angina pectoris].
AB - PURPOSE: To compare the severity of the coronary heart disease and the presence
of coronary risk factors between angina and myocardial infarction (MI) patients.
METHODS: We studied 62 patients with MI and 129 with angina through coronary
angiography to evaluate occlusion (lesion of 99% or 100%), extent (with a score
of 0-5 derived by the number of vessels affected) and severity (3 groups of
different stenosis degrees). Two experiment observers blindly interpreted the
angiograms. RESULTS: Patients with MI had more occlusions (50% vs 13.2% [p <
0.01]), more severity (79% vs 54.3% with > 90% stenosis [p < 0.02]) and more
extent (2.0 vs 0.87; [p < 0.001]), even when controlled for current coronary risk
factors and disease duration. Smoking was the only independent risk factor
related to MI (p < 0.001). CONCLUSION: Among the studied patients, coronary heart
disease extent and severity was greater in the MI group, as well as the
prevalence smoking.
PMID- 9755532
TI - [Electro-cardiographic correlation in the diagnosis of left ventricular
hypertrophy].
AB - PURPOSE: To compare the efficacy of four electrocardiographic criteria: Sokolov,
Gubner, Cornell and Romhilt indexes, in the diagnosis of left ventricular
hypertrophy (LVH) in hypertensive patients. METHODS: LVH was analyzed in the
electrocardiogram of 30 ambulatory patients presenting with systemic arterial
hypertension, classified as mild, moderate and severe, according to the following
indexes: Sokolov > or = 35 mm, Gubner > or = 22 mm, Romhilt > or = 5 points and
Cornell > or = 20 mm for women and 28 mm for men. Sensitivity, specificity,
diagnostic accuracy and other diagnostic variables were determined Mass index of
the left ventricle, > or = 98 g/m2 for women and > or = 120 g/m2 for men,
obtained by echocardiography, was considered the gold standard for the diagnosis
of LVH. RESULTS: When electrocardiographic criteria were considered separately,
the Sokolov index showed the highest accuracy, with a sensitivity of 40%,
diagnostic accuracy of 50% and specificity of 100%; the second most accurate
index was Gubner, and Romhilt and Cornell indexes followed. When at least one of
the indexes was positive, the sensitivity was 52% and diagnostic accuracy was
57%. CONCLUSION: The four electrocardiographic indexes were not diagnostic of
LVH, when analyzed either separately or together. Considering the high prevalence
of this pathological condition, we conclude that a more accurate diagnostic
method should be used in this diagnosis.
PMID- 9755533
TI - [Catheter ablation of atrial flutter. Electrophysiological characterization of
posterior and septal isthmus block].
AB - PURPOSE: Evaluate the different types of conduction blocks obtained between
inferior vena cava-tricuspid annulus (posterior isthmus) and between tricuspid
annulus-coronary sinus ostium (septal isthmus) after radiofrequency (RF) catheter
ablation of atrial flutter (AFL). METHODS: In 16 procedures, 14 patients (pts), 9
male, with type I AFL underwent RF ablation. Atrial activation around tricuspid
annulus was performed with a 10-bipole "Halo" catheter (H1-2; H19-20). In sinus
rhythm, isthmus conduction was evaluated during proximal coronary sinus (PCS) and
low lateral right atrium (H1-2) pacing, before and after linear ablation.
According to the wave front of impulse propagation we assessed absence of block
(bidirectional conduction); incomplete block (bidirectional conduction with delay
in one front of impulse propagation) and complete block (absence of conduction).
The PCS/H1-2 interval was measured before and after ablation. RESULTS: Complete
isthmus block was achieved in 7 (44%) and incomplete block in 4 (25%) procedures.
Conduction block was not achieved in 5 procedures. At a mean follow-up of 12
months, there were no recurrences in the pts with complete block, whereas AFL
recurred in the 6 pts with incomplete or no conduction block (p < 0.001). Pts
with complete block had delta PCS/H1-2 interval (74.0 +/- 26.0 ms) greater than
incomplete (30.5 +/- 7.5 ms) or absent block (p < 0.05). CONCLUSION: The
verification of complete isthmus conduction block with atrial multipolar mapping
is an effective strategy to assess electrophysiological success and absence of
late recurrence in common atrial flutter ablation.
PMID- 9755534
TI - [Contribution of dynamic electrocardiography by Holter monitoring in the
evaluation of congenital long QT syndrome patients].
AB - PURPOSE: The purpose of this study was to evaluate the value of ambulatory
electrocardiogram as a clinical tool to assess ventricular repolarization in
patients with the congenital long QT syndrome. METHODS: The study population
comprised six patients and their data were compared to a control group of six
patients matched in age and gender. The QT interval (ms), corrected by the heart
rate, was measured in the first minute of each hour using two monitoring leads,
with the mean of six consecutive complexes. The data obtained include the
morphologic pattern of T wave, the mean 24-h QTc interval, relation between QT
and cardiac cycle, QTc variability (assessed calculating hourly standard
deviation of the interval and then obtaining the global 24-h mean), QTc
dispersion (difference between the longest and shortest QTc interval). RESULTS:
In all patients abnormal patterns of T waves were detected with frequent episodes
of T wave alternans. Mean 24-h QTc--patients: 598.2 +/- 73.8 ms; controls: 436.1
+/- 8.9 ms (p = 0.000). Linear correlation and regression between QT and heart
rate-patients: r = 0.812; controls: r = 0.967 (p = 0.000). QTc variability
patients: 36.9 +/- 17.2 ms; controls: 14.7 +/- 2.1 ms (p = 0.01). QTc dispersion
patients: 168.3 +/- 70.2 ms; controls: 53.3 +/- 8.1 ms (p = 0.000). CONCLUSION:
The data showed increased hourly QTc variability. QTc dispersion and worse
correlation between QT and heart rate. This data may reflect an abnormally
augmented ventricular vulnerability.
PMID- 9755535
TI - [Antihypertensive treatment. Prescription and cost of drugs. Survey in a tertiary
care hospital].
AB - PURPOSE: To study the most prescribed anti-hypertensive drugs, evaluating their
agreement with established guidelines and drug cost. METHODS: One hundred and
forty one (101 women, mean age = 53.3 years) hypertensive patients who searched
spontaneous attention were interviewed in a tertiary-care hospital. The inclusion
criteria were previous diagnosis of hypertension and non cardiovascular
complaints. RESULTS: The majority of the 107 (75.9%) patients were on medical
treatment. In those receiving monotherapy, thiazides were the most utilized
drugs, followed by methyldopa, ACE inhibitors, calcium channel-blockers, and beta
blockers. The association with thiazides (26.3%) followed the same preference.
The second most prescribed drug, methyldopa, was the more expensive. Fifty
percent of the patients purchased the drugs at their own expense. CONCLUSION: A
preference for prescription of expensive drugs for hypertension was detected in
this sample in Brazil. This does not agree with major guidelines, mainly the V
JNC, which suggest thiazides and betablockers as first choice drugs for
hypertensives with no complications or associated comorbidity.
PMID- 9755537
TI - [Aneurysm of arterial duct associated to aortic arch interruption].
AB - Aneurysm of the arterial duct is an infrequent finding, which is very rarely
detected prenatally. A case of antenatal diagnosis in a pregnant patient (33
weeks) is reported. The fetus presented an aneurysmatic dilation of the arterial
duct with uniformly enlarged diameter, inserting into the descending aorta, which
was interrupted. The neonate was born by cesarean section and was kept on
postaglandins till the 9th day of life, when he was sent to surgery. During the
surgical procedure, the baby died as a result of biventricular failure. This is
the first report of prenatal association of aneurysm of the ducts anteriosus with
other cardiovascular malformations and emphasizes that this finding does not
always have a benign course.
PMID- 9755536
TI - [Single balloon versus Inoue balloon in percutaneous mitral balloon
valvuloplasty. Short-term results and complications].
AB - PURPOSE: To assess short-term results and complications of percutaneous mitral
balloon valvuloplasty (PMBV) performed with Inoue balloon (IB) and single low
profile balloon (SB). METHODS: We performed 390 PMBV procedures, 29 with IB and
337 with SB. There were no differences in age, sex, echocardiographic score
distribution and echocardiographic mitral valve area (MVA). RESULTS: We performed
29 complete procedures with IB and 330 of 337 in SB group. Comparing IB and pre
and pos-PMBV data we obtained: mean pulmonary artery pressure (MPAP) 36 +/- 15
and 39 +/- 14 mmHg, p = 0.2033, mean mitral gradient 17 +/- 6 and 20 +/- 77 mmHg,
p = 0.0396 and MVA 0.9 +/- 0.2 and 0.9 +/- 0.2 cm2, p = 0.8043 and pos-PMBV:MPAP
25 +/- 8 and 28 +/- 10 mmHg, p = 0.2881, gradient 5 +/- 3 and 5 +/- 4 mmHg, p =
0.2778 and MVA 2.2 +/- 0.2 and 2.0 +/- 0.4 cm2, p = 0.0362. Mitral valve (MV) was
competent in 26 patients in IB and in 280 in SB group and we had +/4 mitral
regurgitation in 3 patients in IB and in 57 in SB group (p = 0.3591) pre-PMBV
respectively and pos-PMBV there was also no difference in MV competence (p =
0.7439). CONCLUSION: Both techniques were effective. Hemodynamic data were also
similar although MVA was greater in IB group after PMBV.
PMID- 9755538
TI - [Hyperhomocysteinemia and vaso-occlusive diseases].
PMID- 9755540
TI - [Effect of eggplant on plasma lipid levels, lipidic peroxidation and the
reversion of endothelial dysfunction in experimental hypercholesterolemia].
PMID- 9755539
TI - [Stents. Review of the literature].
PMID- 9755541
TI - [Effect of eggplant on plasma lipid levels, lipidic peroxidation and the
reversion of endothelial dysfunction in experimental hypercholesterolemia].
PMID- 9755542
TI - [Teaching at the bedside--a solid truth].
PMID- 9755543
TI - [Efficacy of and tolerance to salmeterol compared to salbutamol in patients with
bronchial asthma].
AB - Beta 2-agonists are considered one of the cornerstones of the asthma therapy, but
their short action requires frequent administration and an association with other
broncodilators. The development of long-acting beta 2-agonists may represent an
important improvement in asthma treatment. PURPOSE: The present study was
designed to assess the efficacy and safety of inhaled salmeterol compared to
salbutamol in patients with mild-to-moderate asthma. METHODS: After the two run
in weeks, the patients received either salmeterol 50 mg twice a day or salbutamol
200 mg four times a day, over a four week period, following a double blind,
parallel group study. Sixty patients had the following inclusion criteria: FEV1 >
50% or PEFR over the past seven days > 50% of predicted normal; reversibility of
FEV1 > 15%; symptoms scores > 2 (score 0 and 5) in 4 of the last seven days or
PEFR variation > 15%. RESULTS: Seven patients discontinued the protocol (see
methods). Of the 53 analyzable patients, 25 were of the salmeterol group and 28
of the salbutamol group. Our results showed that in the run-in period there were
not differences among the groups comparing the values of FEV1 in % predicted,
morning PEFR and asthma symptoms scores. The improvement rate of morning FEV1 and
PEFR in patients who received salmeterol was significantly higher (p < 0.05)
compared to the patients who received salbutamol, for two and four weeks of
treatment. Also, the salmeterol group have shown reduction of the symptoms in the
nocturnal period(significantly in the first fortnight of treatment) demonstrated
by the significative increase in the symptoms improvement rate when compared
salmeterol and to salbutamol groups. The number of rescue medication inhaled,
side effects, heart rate, blood pressure, serum potassium dosage and
electrocardiograms, did no show significative differences between the groups.
CONCLUSION: This study showed that in mild to moderate asthmatic patients,
salmeterol in the dosage of 100 mg/day raised the FEV1 and the morning PEF and
led to pronounced decrease in the nocturnal symptoms as compared to salbutamol.
The side effects were similar.
PMID- 9755544
TI - [Measuring cyclosporine levels in whole blood in kidney transplantation].
AB - BACKGROUND: Cyclosporin A is a potent immunosuppressive drug effective in
combatting rejection following organ transplantation. In na effort to replace a
radioimmunoassay (RIA) for whole blood determination of cyclosporine (Cya) we
compared RIA with fluorescence polarization immunoassay (FPIAm). METHOD: 65 blood
samples were analysed from kidney transplanted patients. The samples were
collected into tubes containing EDTA as anticoagulant and analysed by RIA and
FPIAm. RESULTS: The statistical analysis revealed a difference between both
methods (p < 0.05). The linear-regression comparison of Cya concentration
measured by RIA and FPIAm showed the following relationship: Cya(FPIAm) = 1.06 x
Cya(RIA) + 5.8 (r = 0.9817). CONCLUSION: We conclude that FPIAm provides na
alternative method for measuring cyclosporine in whole blood with the added
advantages of being reasonably rapid, precise and easy to perform.
PMID- 9755545
TI - [Technical aspects of esophagocardiomyotomy with divulsion for the surgical
treatment of non advanced chagasic megaesophagus].
AB - BACKGROUND: The authors describe a Heller's technique alteration used for
treatment of early Chagasic megaesphagus (ECM): esophagocardiomyotomy with
divulsion plus esophagocardiopexy. PATIENTS AND METHODS: Between June 1988 and
March 1996, fifty patients were operated on at Surgery Department of FAMEMA. All
had chagasic megaesophagus degrees I, II and III. RESULTS: The results were
excellent in 86% (43/50) and good in 14% (7/50), for 6 months to 7.6 years of
follow up. The radiological and endoscopic studies showed neither esophagic
stasis nor food residues and esophagitis. CONCLUSION: The authors concluded that
esophagocardiomyotomy with divulsion plus esophagocardiogastropexy is efficient
in ECM degrees I, II e III and emphasize both technical facility and security.
PMID- 9755546
TI - [Immunological indicators (IgM and C-reactive protein) in neonatal infections].
AB - Sepsis in the neonatal age is associated with risk factors for infections and
with the immunological state of the newborn infant. BACKGROUND: Verify if IgM and
C-reactive protein were indicators of infection in newborn infants with risk
factors. MATERIAL AND METHODS: We studied 57 newborn infants that had: premature
rupture of amniotic membranes associated ou no with clinical amniotics or with
urinary tract infection. They were classified in three gestational age groups (<
34 weeks, between 34-36 6/7 and (37 weeks) Sepsis diagnosis was made through
clinical and laboratorial criterious and we also included: IgM and C-reactive
protein obtained of the newborn at birth and at fifth day of life. RESULTS:
Sepsis diagnosis was made in 18 (31.5%) of 57 newborn infants, 13 (22.8%) with
early sepsis and 5 (8.7%) with late sepsis. The infection had statistical
association with gestational age and with weight at birth. The gestational group
< 34 weeks was more infected and in this group the number of newborn that died
had association with infection. We did not observed association in the three
groups studied between infection and sex. There were significant differences of
levels of IgM between infected and not infected newborn infants in the same group
of gestational age, this difference was more evident in the fifth day. There were
association between levels of C-reactive protein > 10 mg/L and infection in the
three groups studied. CONCLUSION: C-reactive protein was the better indicator of
infection at birth and in the fifth day of life and this was very important for
the clinical evolution of the infection and in the late sepsis was the first
prove that was altered.
PMID- 9755547
TI - [Increase in the frequency of norfloxacin and ciprofloxacin resistance of
bacteria isolated from urine culture].
AB - OBJECTIVE: To assess time trends in the frequency of norfloxacin and
ciprofloxacin resistance of bacteria isolated from urine culture. METHODS:
Results of all urine cultures with a bacterial growth of at least 10(5) colony
forming units per milliliter, performed at the Renal Service of the Federal
University of Bahia, Brazil, from 1983 to 1994 were analyzed. The bacteria
considered for this analysis were those most often isolated: Escherichia coli (n
= 668), Klebsiella spp. (n = 286), Staphylococcus spp. (n = 186), Proteus spp. (n
= 135) and Enterobacter spp. (n = 129). RESULTS: The frequencies of norfloxacin
resistance for the periods 1983-1986, 1987-1990 and 1991-1994 were 3.2%, 5.9% and
9.1%, respectively (p-value < 0.05). The most pronounced increases in the
frequencies of norfloxacin-resistance were observed for Klebsiella spp. and
Enterobacter spp. The frequency of ciprofloxacin resistance was 7.4% in the
period 1985-1989 and 16.5% in the period 1990-1994 (p-value < 0.05). This time
trend in ciprofloxacin resistance was more striking for Enterobacter spp. and
Staphylococcus spp. CONCLUSION: The results show a gradual increase in the
frequency of norfloxacin and ciprofloxacin resistance of the bacteria most
commonly isolated from urine cultures. The influence of previous treatment with
quinolones and characteristics of the infecting bacteria on these findings are
important questions to to be addressed in future investigations.
PMID- 9755548
TI - [Blood component transfusion in full-term and premature new born infants].
AB - BACKGROUND: Blood transfusion requirements for preterm infants are greater than
for newborn ones. We compare blood transfusion requirements for newborn and
premature infants and their pathology: clinical or surgical; hemorrhagic
accidents and survival. METHODS: 48 newborns classified in 2 groups: 26 newborn
and 22 preterm infants received 251 units of blood components: 177 units of red
cell concentrates, 36 of platelet concentrates, 30 of fresh frozen plasma and 8
of total blood in a 186 days period. We analyzed total requirements of components
in each group and daily, under a live-infant/day rate until 120 days. RESULTS:
The all-components median requirements were 7.31 units for premature and 3.46 for
newborn infants. Daily requirements analyzes reveal that requirements were
greater before 60th day of life (d.l.) on clinical patients and after 86th d.l.
may be caused by surgical acts. Hemorrhagic accidents happen on premature with
less than 60,000 platelets/mm3. The survival wave by number of transfusions,
until 186 d.l., show an inversely proportional trend between the number of
transfusions done and the hope of life. CONCLUSIONS: Blood requirements for
preterm infants are greater than for term ones. Those requirements are related to
their pathology. Prophylatic platelet transfusions may reduce hemorrhagic
accidents then red blood cell transfusions in preterm infants group. The number
of transfusions over 10 is a surrogate marker of bad prognosis for both groups up
to 120 d.l.
PMID- 9755549
TI - [Frequency of stenosis of renal the artery in 676 renal transplantations].
AB - Kidney transplantation is the permanent and safe treatment for patients with
chronic renal failure, although surgical treatment is susceptible both to
urological and many vascular complications, and post-transplantation, renal
artery stenosis being the most important. OBJECTIVE: To verify the incidence of
renal artery stenosis of 676 patients submitted to renal transplants, from living
and cadaver donors, in the period of February of 1985 to December of 1994, when
compared the end-to-end and end-to-side anastomosis with the external iliac
artery of the recipient. METHODS: The data shown were obtained from charts of 676
patients submitted to renal transplants performed by the same surgery staff at
the Hospital Sao Paulo--Universidade Federal de Sao Paulo--Escola Paulista de
Medicina, between 1985 and 1994. RESULTS: Eleven cases (1.63%) of post
transplantation renal artery stenosis were found. CONCLUSION: 1) Frequency of
post-transplantation renal artery stenosis was low and observed only in
recipients of cadavers donors. 2) Frequency of post-transplantation renal artery
stenosis with end-to-end artery anastomosis did not significantly differ from end
to-side anastomosis. 3) Age, sex and ethnic groups of patients did not interfere
in the frequency of renal artery stenosis.
PMID- 9755550
TI - [Development of puberty in girls treated for acute lymphocytic leukemia].
AB - BACKGROUND: In order to evaluate the puberal development of girls treated by
Acute Lymphocytic Leukaemia (ALL) a retrospective study was done at Campinas-SP,
Brazil. MATERIAL AND METHODS: Forty two girls were treated by ALL with either 18
or 24 Grays of cranial irradiation. All patients were treated with chemotherapy
including intrathecal methotrexate in similar dose regimens in either groups.
RESULTS: The results showed lower mean ages at telarche, pubarche and menarche in
the treated group, mainly in the group treated before five years old. No
differences were observed in the 18 Grays or 24 Grays group. CONCLUSIONS: Our
data suggest that girls treated by ALL have a precocious puberal development.
PMID- 9755551
TI - [Surgical removal of pulmonary metastasis: prospective study in 182 patients].
AB - PURPOSE: The present study evaluates the results of surgical treatment of lung
metastases, as well as attempts to identify subgroups of patients who would
benefit the most from the operation. CASE AND METHODS: This is a prospective
analysis of patients with history of neoplasia, submitted to resection of
pulmonary nodules, with the diagnosis or suspicion of metastases. The 182
patients were operated upon through a lateral thoracotomy. RESULTS: The patients
submitted to pulmonary resection for suspected metastases showed no malignant
tissue in 34 patients (18.6%), and in six patients (3.2%) were diagnosed a second
lung primary tumor. Overall survival of the patients was 28% at 56 months, and
disease-free survival was 9%. Multivariate analysis showed that disease free
interval (p = 0.002), complete resection (p = 0.039), and number of malignant
nodules resected (p = 0.016) significantly affected overall survival. Disease
free survival was affected only by complete resection (p = 0.0001) and number of
malignant nodules resected (p = 0.004). CONCLUSION: Resection of pulmonary
metastasis improve survival in a selected group of patients. More studies are
necessary to define the value of other therapies in the results of survival in
resected pulmonary metastasis.
PMID- 9755552
TI - [Cholangiopancreatography with magnetic resonance: a new approach for assessing
the bile and pancreatic ducts].
PMID- 9755553
TI - [Chest pain in patients with normal coronary angiography (syndrome X): new
concepts].
PMID- 9755554
TI - [Work shifts, sleep and biological rhythms].
PMID- 9755555
TI - [Lung volume reduction--surgical alternative to the treatment of severe diffuse
pulmonary emphysema?].
PMID- 9755556
TI - [Ph1-positive acute myeloid leukemia de novo or blast crisis of chronic myeloid
leukemia? Molecular analysis and clinical course of a case].
AB - A case of AML presented with basophilia in peripheral blood and Ph1 chromosome in
karyotype analysis is reported. After one year of treatment with intensive
chemotherapy and clinical and hematological remission, molecular analysis (RT
PCR) detected minimal residual disease (b2-a2 rearrangement). Thus, the patient
relapsed as AML and, after second remission, he developed a hematological picture
of chronic CML. Ten months later, he relapsed again as AML. The difficulties of
diagnosis between AML Ph1-positive de novo and myeloid blast crisis of CML, as
the first manifestation of disease, based on clinical and molecular aspects are
discussed.
PMID- 9755557
TI - [Reconstructive surgery of the lower lip with esthetic-functional recovery:
report of 2 cases].
AB - Two cases of patients with large squamous cell carcinoma in the lower lip, that
were submitted to the reconstructive surgery, using technique of lateral progress
with reconstruction of the red lip, always tends the concern of the recovery not
only functional as well as aesthetic of these patients ones, are reported. A
classification is given suggesting the main locations of the squamous cell
carcinoma of the lip, allowing better definition with relationship to the
surgical technique to be used in each case, depending on the location and
involvement or not of the lip comissure.
PMID- 9755558
TI - Meningococcal disease caused by Neisseria meningitidis serogroup B serotype 4 in
Sao Paulo, Brazil, 1990 to 1996.
AB - A large epidemic of serogroup B meningococcal disease (MD), has been occurring in
greater Sao Paulo, Brazil, since 1988. A Cuban-produced vaccine, based on outer
membrane-protein (OMP) from serogroup B: serotype 4: serosubtype P1.15
(B:4:P1.15) Neisseria meningitidis, was given to about 2.4 million children aged
from 3 months to 6 years during 1989 and 1990. The administration of vaccine had
little or no measurable effects on this outbreak. In order to detect clonal
changes that could explain the continued increase in the incidence of disease
after the vaccination, we serotyped isolates recovered between 1990 and 1996 from
834 patients with systemic disease. Strains B:4:P1.15, which was detected in the
area as early as 1977, has been the most prevalent phenotype since 1988. These
strains are still prevalent in the area and were responsible for about 68% of 834
serogroup B cases in the last 7 years. We analyzed 438 (52%) of these strains by
restriction fragment length polymorphism (RFLPs) of rRNA genes (ribotyping). The
most frequent pattern obtained was referred to as Rb1 (68%). We concluded that
the same clone of B:4:P1.15-Rb1 strains was the most prevalent strain and
responsible for the continued increase of incidence of serogroup B MD cases in
greater Sao Paulo during the last 7 years in spite of the vaccination trial.
PMID- 9755559
TI - Frequency of dermatophytes in the metropolitan area of Porto Alegre, RS, Brazil.
AB - In order to evaluate the distribution of dermatophytes in Porto Alegre, the
capital of the state of Rio Grande do Sul, Brazil, they were isolated from the
skin, hairs and nails samples and retrospectively analyzed from June 1981 to June
1995, in two different institutions in the city of Porto Alegre: (i) the Servico
de Micologia do Instituto de Pesquisas Biologicas Jandyr Maya Faillace, da
Secretaria de Saude e Meio Ambiente do Rio Grande do Sul which attends the low
income population (low and middle classes) and, (ii) Laboratorio Weinmann, a
clinical pathology laboratory which attends predominantly the higher income
population (middle and upper classes), both which attend in the metropolitan area
of Porto Alegre. The dermatophyte predominance of Trichophyton rubrum was
confirmed (55.33%) followed by T. mentagrophytes (21.46%). The data obtained were
compared with the existing prevalence data which were collected in the interior
of the state over a period of 32 years (1960-1992). T. verrucosum, T. simii,
Microsporum persicolor, T. schoenleinii, M. nanum and M. cookei were isolated in
the interior and have not been found in the capital so far. On the other side, T.
violaceum was, isolated in the capital and has not been found in the interior so
far.
PMID- 9755560
TI - Evolution of IgG antibody response against Toxoplasma gondii tissue cyst in acute
and chronic human infections.
AB - The recognition profile of the tissue cysts antigens by IgG antibodies was
studied during acute and chronic human toxoplasmic infection. Thus the IgG
response against Toxoplasma gondii was investigated by immunoblotting in two
patients accidentally infected with the RH strain as well as in group of
naturally infected patients at acute and chronic phase. There was an overall
coincidence of molecular mass among antigens of tachyzoites and tissue cysts
recognized by these sera, however, they appear not to be the same molecules. The
response against tissue cysts starts early during acute infection, and the
reactivity of antibodies is strong against a wide range of antigens. Six bands
(between 82 and 151 kDa) were exclusively recognized by chronic phase sera but
only the 132 kDa band was positive in more than 50% of the sera analysed. A
mixture of these antigens could be used to discriminate between the two infection
phases. The most important antigens recognized by the acute and the chronic phase
sera were 4 clusters in the ranges 20-24 kDa, 34-39 kDa, 58-80 kDa and 105-130
kDa as well as two additional antigens of 18 and 29 kDa. Both accidentally
infected patients and some of the naturally infected patients showed a weak
specific response against tissue cyst antigens.
PMID- 9755561
TI - A comparative epidemiologic study of specific antibodies (IgM and IgA) and
parasitological findings in an endemic area of low transmission of schistosoma
mansoni.
AB - The diagnostic potential of circulating IgM and IgA antibodies against
Schistosoma mansoni gut-associated antigens detected by the immunofluorescence
test (IFT) on adult worm paraffin sections was evaluated comparatively to the
fecal parasitological method, for epidemiological purposes in low endemic areas
for schistosomiasis. Blood samples were collected on filter paper from two groups
of schoolchildren living in two different localities of the municipality of
Itariri (Sao Paulo, Brazil) with different histories and prevalences of
schistosomiasis. The parasitological and serological data were compared to those
obtained for another group of schoolchildren from a non-endemic area for
schistosomiasis. The results showed poor sensitivity of the parasitological
method in detecting individuals with low worm burden and indicate the potential
of the serological method as an important tool to be incorporated into
schistosomiasis control and vigilance programs for determining the real situation
of schistosomiasis in low endemic areas.
PMID- 9755562
TI - Questionnaires in the screening for Schistosoma mansoni infection: a study of
socio demographic and water contact variables in four communities in Brazil.
AB - The use of questionnaires has been recommended for identifying, at a lower cost,
individuals at risk for schistosomiasis. In this study, validity of information
obtained by questionnaire in the screening for Schistosoma mansoni infection was
assessed in four communities in the State of Minas Gerais, Brazil. Explanatory
variables were water contact activities, sociodemographic characteristics and
previous treatment for schistosomiasis. From 677, 1474, 766 and 3290 individuals
eligible for stool examination in the communities, 89 to 97% participated in the
study. The estimated probability of individuals to be infected, if they have all
characteristics identified as independently associated with S.mansoni infection,
varied from 15% in Canabrava, to 42% in Belo Horizonte, 48% in Comercinho and 80%
in Sao Jose do Acacio. Our results do not support the hypothesis that a same
questionnaire on risk factors could be used in screening for S.mansoni infection
in different communities.
PMID- 9755563
TI - Rubber contact dermatitis in patients attended at Walter Cantidio Hospital,
Federal University of Ceara, Brasil.
AB - Nowadays 70% of the world's rubber supply is synthesized artificially. The
process involved in its manufacture is vulcanization which requires many chemical
substances for speeding the process, as antioxidants to prevent deterioration of
rubber, or others. These substances may constitute important sensitizers and thus
be responsible for dermatological diseases like contact dermatitis. The objective
of this study is to search for the main sensitizers among these rubber chemicals
in a population mostly composed by women of a tropical country and compare the
results with the ones obtained from previous studies which tested populations
mainly composed by men and on different climates.
PMID- 9755564
TI - Duality of patterns in hepatitis A epidemiology: a study involving two
socioeconomically distinct populations in Campinas, Sao Paulo State, Brazil.
AB - To evaluate the prevalence of antibodies against hepatitis A in two
socioeconomically distinct populations, 101 and 82 serum samples from high and
low socioeconomic groups, respectively, were analysed for the presence of IgG
anti-HAV using a commercial ELISA. The prevalence in low socioeconomic level
subjects was 95.0%, whereas in high socioeconomic subjects was only 19.6% (p <
0.001). These data show a duality in Brazil: anti-HAV prevalence in low
socioeconomic subjects is similar to that of developing countries, while in high
socioeconomic subjects, a pattern typical of developed countries is found. The
control of this infection in our country is primarily related to the improvement
of sanitation, but especially for high socioeconomic level populations, the use
of vaccination against hepatitis A is strongly advisable to avoid the occasional
appearance of this disease in adults.
PMID- 9755565
TI - The control of anopheline mosquitos by the spraying of Deltamethrin on raffia
curtains used in miners' huts in areas endemic for malaria.
AB - The residual potential of an aqueous solution of Deltamethrin (FW 25 mg i.a./m)
was evaluated on raffia curtains. These are sheets of synthetic material used in
the construction of huts to house miners. Experiments were conducted during 420
days and the curtains were always rolled up in the daytime and unrolled in late
afternoon. Data analyzed by logarithmic regression indicated that raffia treated
with Deltamethrin had higher mortality indices than that covered with DDT. The
residual capacity of Deltamethrin on raffia was high. The mortality percentage
was above 85% after 360 days and dropped to about 50% at 420 days. The effect of
DDT was reduced after 180 days and reached zero by the end of the experiment.
Based or the results of these experiments, it is recommended that Deltamethrin be
used to spray raffia curtains in mining regions and other areas that are endemic
for malaria.
PMID- 9755566
TI - The use of oligonucleotide probes for meningococcal serotype characterization.
AB - In the present study we examine the potential use of oligonucleotide probes to
characterize Neisseria meningitidis serotypes without the use of monoclonal
antibodies (MAbs). Antigenic diversity on PorB protein forms the bases of
serotyping method. However, the current panel of MAbs underestimated, by at least
50% the PorB variability, presumably because reagents for several PorB variable
regions (VRs) are lacking, or because a number of VR variants are not recognized
by serotype-defining MAbs. We analyzed the use of oligonucleotide probes to
characterize serotype 10 and serotype 19 of N. meningitidis. The porB gene
sequence for the prototype strain of serotype 10 was determined, aligned with 7
other porB sequences from different serotypes, and analysis of individual VRs
were performed. The results of DNA probes 21U (VR1-A) and 615U (VR3-B) used
against 72 N. meningitidis strains confirm that VR1 type A and VR3 type B encode
epitopes for serotype-defined MAbs 19 and 10, respectively. The use of probes for
characterizing serotypes possible can type 100% of the PorB VR diversity. It is a
simple and rapid method specially useful for analysis of large number of samples.
PMID- 9755567
TI - Hemorrhagic syndrome and acute renal failure in a pregnant woman after contact
with Lonomia caterpillars: a case report.
AB - A case of a 37-week pregnant woman who developed a hemorrhagic syndrome and acute
renal failure after contact with Lonomia caterpillars is reported. The accident
also initiated labour and the patient gave birth to an alive child. Some
pathophysiological aspects of the genital bleeding and of the acute renal failure
are discussed.
PMID- 9755568
TI - An unusual ground larval habitat of Aedes albopictus.
PMID- 9755569
TI - Immune response and severity of pulmonary tuberculosis in children.
PMID- 9755570
TI - [The classical or laparoscopic operation in inguinal hernias].
AB - AIM: Results evaluation in two trials of patients undergoing classical or
laparoscopic surgery for inguinal hernia. MATERIAL AND METHOD: We compared 2
homogeneous trials of 80 patients with inguinal hernias treated by classic
procedures: Bassini, Shouldice, Lichtenstein (trial I) or by laparoscopic
approach with Plastex, Mercilene or Prolene prosthesis (trial II) between 1995
1997. RESULTS: Postoperative morbidity consisted in trial I in 5 seromas, 2
hematomas, 4 cases with neuralgic pain, 1 with testicular hypotrophy and 4
recurrences. In this trial the mean operative time was 22 min. and the mean
hospitalization was 7 days. In trial II we registered a parietal bleeding at a
lateral port imposing the conversion, 3 serohematomas, 2 recurrences by
displacement of the prosthesis and 2 cases of neurologic pain. The mean operative
time was 50 minutes and the mean hospitalization was 3 days. CONCLUSION: In spite
of the longer operative time and the higher cost (the price of the prosthesis),
in trial II the benefits of shorter hospitalization, lower morbidity and rapid
socioprofessional reintegration are significant.
PMID- 9755571
TI - [The laparoscopic approach to the retroperitoneal space].
PMID- 9755572
TI - [The indications for and limits to the surgical treatment of congenital
dilatations of the intra- and extrahepatic bile ducts].
AB - Congenital cystic dilatations of the biliary ducts are defects in the genetic
program which are transmitted in an autosomal recessive way. Todani classified
cystic dilatations of extra and intrahepatic ducts in 5 types. In classified
cystic dilatations of extra and intrahepatic ducts in 5 types. In "N. Gh. Lupu"
Surgical Clinical were treated 9 cases of congenital dilatations of the biliary
tree during the last 40 years (1958-1998); five of them were belonging to the
type V Todani (Caroli's disease), three to the type I Todani and one case in the
type IV a of Todoni's classification. The mean age of the patients was 42.4
years, five of them being men and 4 women. Surgical treatment was particular to
each case depending on age, associated diseases, the length of disease's
evolution and the general state of the patient. The prognosis of this disease is
a reserved one.
PMID- 9755574
TI - [Occult breast cancer].
AB - In 20 years we registered seven observations of breast cancer presenting as an
axillary mass (BCAM), meaning 0.9% out of the global breast cancer series (767
cases). All the cases were females. The main clinical sign was only the presence
of axillary lymph nodes. Diagnosis was precised by the pathological examination
of the excised nodes (six observations) or needle aspiration of the axillary
lymph nodes. Mammography showed tumors less than one centimeter in three out of
the seven cases. As for the stadialisation, we had two cases in the II-nd stage,
four patients in the III-rd stage and one in IV-th. All the patients were
operated on. There were four simple mastectomies anti three Patey radical
modified mastectomies. Postoperative chemotherapy and radiotherapy were performed
to all the patients. Only two of the seven patients survived five years after
surgery.
PMID- 9755573
TI - [A plea for the conservative treatment of breast cancer].
AB - This article is a plea for the implementation of early-stage breast cancer
conservative therapy into as many surgical clinics as possible. The
aforementioned statement relies mainly on published papers and data (the protocol
included) provided to us by Instituti Clinici di Perfezionamento di Milano
experts in breast cancer conservative therapy and to a lesser extent on our not
too numerous results (30 cases) obtained over the past 2 years since we applied
the Milano protocol on a regular basis. Thus we support the view that the breast
conserving treatment is suitable for clinical stage I or II carcinoma whose
tumors are 3 cm or less in greatest diameter, provided axillary lymphadenectomy
is associated for prognostic and future management guidance reasons, but not for
cure. Breast-limited postoperative radiation treatment is foremost aimed at local
recurrences rate reduction without significantly influencing survival rate.
Postoperative chemotherapy, indicated for node-positive patients and/or primary
tumors over 1 cm in greatest, diameter, has been proved to contribute to long
term survival rate. However, both the small sample size and the short period of
observation of our study prevented us from drawing firm conclusions directly.
PMID- 9755575
TI - [The duodenal compression syndrome (DCS) due to an aorto-mesenteric shunt
associated with primary intestinal malrotation].
AB - It is presented the cases of a patient suffering from a rare surgical condition,
Wilkie's syndrome, duodenal compression syndrome through aorto-mesenteric clamp,
also known as the superior mesenteric artery syndrome (SMAS). The authors wish to
underline the diagnosis difficulties which concurred to a delay of surgical cure,
also presenting the surgical technique methods used for solving this case. Among
the large number of operations till now proposed for the management of this
syndrome, the chosen solution-resection of the first jejunal loop together with
the duodenojejunal junction followed by prevascular lateroterminal duodenojejunal
anastomosis--was imposed by the coexistence of an intestinal malrotation, forming
the so called "common mesentery".
PMID- 9755576
TI - [Rectal hemangioma--a pseudoneoplastic form. A case report and review of the
literature].
AB - A patient, 23 years old, is presented. He was admitted on in our clinic for a
lower, very bleeding rectal tumor, the macroscopically characters evoking quite
sure a malignant neoplasm. Three successive histopathologically examinations
remained inconclusive and only the fourth suggested the diagnosis of benign
glandular polyp. That conclusion strongly contrasted with all the data obtained
by the macroscopically examinations. Nevertheless the therapeutically option was
in favor of a sphincter-saving surgery, the practiced operation being a pull
through rectosigmoid resection (Babcock). Recovery of the patient which is in a
good condition at present (two years after surgery). The histopathological
examination of the operative specimen stipulated like diagnosis: rectal
haemangioma with component parts of lymphangioma. Carrying on, the paper
presented a review of the literature data referring to the very limited
experience of others authors, regarding clinical aspects, diagnostics and
therapeutically problems of the rectal haemangioma. In similar cases presenting
voluminous rectal (or colonic) possibly benign tumors, haemangioma like,
macroscopically diagnostic being difficult or unsure, but also without a
certitude for a malignant tumor, it is recommended a sphincter-saving operation,
adapted to the general status of the patient. In cases with malignant characters
at the final histopathological examination, on the operative specimen, the
transformation of the initial intervention in a amputation type surgery may be a
possible alternative.
PMID- 9755577
TI - [A voluminous hepatic hydatid cyst of the right lobe in a patient with
hypertrophic liver cirrhosis--comments on a case].
AB - There is presented the case of a patient with liver cirrhosis hepatomegalic form,
echinococcosis and gallbladder stones. After the presentation of the clinical
findings, there are discussed the problems of the surgical treatment. The
remaining cavity was treated by pericysto-jejunostomy. The postoperative recovery
was uneventful.
PMID- 9755578
TI - [Myocardial revascularization interventions].
AB - Elective coronary artery bypass surgery (CABG) can be performed with low
operative mortality. There is a controversial discussion whether short- and long
term results of CABG can justify this procedure even in elderly patients.
MATERIAL AND METHODS: We retrospectively evaluated the clinical profile,
operative procedure, postoperative short- and long-term results of 1127 patients
over 70 years of age who underwent myocardial revascularization between January
1985 and December 1996. RESULTS: Mean age was 73.9 years. In 1996,
septuagenarians represented 21.5% of our operated coronary patients, when
compared with 6.4% in 1985. Analysis of risk factors showed an increasing
prevalence of renal failure, obesity, hyperuricemia and a history of smoking.
Preoperatively 87% of our patients were in NYHA-class III and IV. The percentage
of emergent operations decreased over the observed period by 10.3%. Internal
mammary artery was used with increasing frequency (44.8% in 1985-92 vs. 61.5% in
1993-96). The number of simultaneous valve replacements increased, too.
Postoperatively, we noted rising incidence of respiratory failure (17.1%) and
neurological disorders (13.7%). On the other hand, the need for intraaortic
balloon pumping and hemofiltration declined by 6.6% and 2.9%. Perioperative
mortality (< or = 24 h) was 3.65%, hospital mortality (< or = 30 days) was 9.64%.
Actuarial 1 year at was 82% (+/- 4.3%), and 65.7% (+/- 3.8%) at 5 years.
CONCLUSIONS: Our data suggest that CABG can be performed in septuagenarians with
an acceptable operative risk. Since the large majority of patients improve
symptomatically, surgery is the recommendable option for a growing number of
elderly patients suffering from severe angina.
PMID- 9755579
TI - [The place of laparoscopy in assessing and treating a pain syndrome of the right
iliac fossa].
AB - The study is considering a trial of 87 patients (61 women 17 and 76 years old)
admitted in our clinic between 1995-1996. The preoperative diagnosis was
coincident with the laparoscopic one in 10 cases the laparoscopic one in 10 cases
the laparoscopy completed the diagnosis and in 12 cases it showed out other
organ's disease, evicting useless operations. In the 87 patients we performed: 53
appendectomies, 20 oophorectomies, 15 partial oophorectomies, 9 right
adnexectomies, 2 adhesiolysis, 2 lymph node biopsies, 1 epiploic fringe excision
for necrosis, 1 appendicular stump removal. The evolution was favourable in all
patients, the mean postoperative hospitalization was 48 hours.
PMID- 9755580
TI - [Total gastrectomy with mechanical sutures].
AB - Between 1994-1996, nine consecutive patients underwent total gastrectomy with
stapled sutures for II, III or IV TNM stage carcinoma (8 patients) or lymphoma (1
patient) of the middle or upper stomach. Digestive continuity was established by
stapled end-to-side "ended", end-to-side and end-to-end Roux-en-Y (7 patients)
and omega loop (2 patients) esophagojejunal anastomoses using circular staplers
(EEA or ILS). The duodenal stump and the end of the Roux loop were closed with TA
55 or TA 30 linear stapler. Interjejunal anastomoses were hand sewn. Nasojejunal
feeding catheter was placed for ten days in all patients. No postoperative
mortality non anastomotic fistula occurred. One patient had duodenal stump
leakage which closed spontaneously. In three patients postoperative chemotherapy
with 5-FU and Leucovorian was associated. At late follow-up, there were two
patients with reflux esophagitis cured by medical treatment and one patient with
peritoneal and hepatic metastases at relaparotomy. In conclusion, the use of
stapled sutures in total gastrectomy facilitates esophagojejunal anastomosis and
improves suture reliability.
PMID- 9755581
TI - [An iliac-mesenteric-atrial shunt in the Budd-Chiari syndrome with extensive
thrombosis of the inferior vena cava].
AB - A 34-year-old woman with no history of any liver diseases was admitted to the
service for a Budd-Chiari syndrome and an extensive thrombosis of the inferior
vena cava. The symptoms of the portal hypertension were present, with an enormous
ascites, mild esophagogastric varices, associated with increased edema of the
lower limbs, perineum and abdominal wall. The diagnosis was established by color
Doppler ultrasonography, CT and cavography. An ilio-mesenterico-atrial shunt,
between the right iliac vein, the superior mesenteric vein and the right atrium
was successfully performed, transdiaphragmatically, by abdominally and right
thoracic approach, using a 35 cm Dacron prosthesis. Postoperative evolution was
very good. The color Doppler ultrasonography showed a good flow in the shunts.
After 14 days ascites decreased over 70% and the inferior edema almost
disappeared. 2 month later ascites decreased over 80%, the esophageal varices and
edema disappeared completely. To our knowledge, this is the first case in the
country, in which a patient underwent ilio-mesenterico-atrial shunt for Budd
Chiari syndrome and inferior vena cava extensive thrombosis.
PMID- 9755582
TI - [An endoscopic treatment alternative in vesico-ureteral reflux (VUR)].
AB - Vesicoureteral reflux (VUR) represent an important pathology (surgical treatment
was until recently the "gold standard" therapy) in urology. Between September
1995 and October 1997 we used endoscopic Romanian collagen injection in 21 cases
with VUR (3 cases grade II, 14 cases grade III, 4 cases grade IV). The collagen
solution (1/1 with distilled water) was injected at the 6 hour of the ureteral
large ostium (15/35 ml). In some cases we obtained the perfect occlusion of the
incompetent ureteral ostium by complementary injections at 3 and 9 hours. It was
necessary to reinject collagen twice in 8 cases and three times in 3 cases.
Success rate appeared in 66.66% cases. We did not confront ourselves with
postoperative complications. Hospitalization period was 3.2 days. The mean follow
up period was 12 months (range 6 to 28). Our results prove that endoscopic
collagen injection applied in VUR is a simple, efficient, without complications
method, minimally invasive.
PMID- 9755583
TI - [An endoscopic treatment method for postoperative stenoses].
AB - The endoscopic procedures include a great variety of procedures for the treatment
of the upper and lower gastrointestinal bleeding of the benign and malign
jaundice, of the primary or secondary gastrointestinal strictures. The authors
present the case of a patient with a postcaustic oesophageal stricture for whom
the surgical treatment was an esogastroanastomosis. Quite early in the
postoperative course the anastomosis got, very tight due to a anastomotic
fistula, and we succeed to dilate it with endoscopic procedures.
PMID- 9755584
TI - [Synthetic fabrics in reparative surgery of the abdominal wall].
AB - Prosthesis use in surgical repair of abdominal wall is becoming nowadays a
worldwide method, being imposed by its efficiency in solving the defects. The
authors are speaking in the light of their experience gained with 100 patients
that underwent the operation of prosthesis implant inside the abdominal wall
between 1990 and 1996. There have been correlated the early and late
postoperative results with some features of this surgical procedure (see below),
to prove its efficacy. The authors discuss some principles of alloplastic
treatment, which represent also the conclusions of the study: the moment of when
a prosthesis is recommended, the choice of synthetic material, where and how is
placed the prosthesis, some additional measures which contribute to therapeutic
success.
PMID- 9755585
TI - [The advantage of preparing the colon with Fortrans for diagnostic explorations
or surgical interventions].
PMID- 9755586
TI - Two endemic foci of heterophyids and other intestinal fluke infections in
southern and western coastal areas in Korea.
AB - Two endemic foci of heterophyid infections were discovered in coastal villages of
Puan-gun, Chollabuk-do, and Sachon-gun. Kyongsangnam-do, Korea. Fecal
examinations were performed on 153 inhabitants of Puan-gun and 138 of Sachon-gun,
using cellophane thick smear and formalin-ether sedimentation technique. The
helminth egg and/or protozoan cyst positive rate was 21.5% (33/153) in Puan-gun
and 39.1% (54/138) in Sachon-gun. In Puan-gun, the egg positive rate of
heterophyids was the highest, 17.6%, and that of other parasites was 0.7-2.6% by
parasite species. In Sachon-gun, that of heterophyids was 18.8%, followed by
Clonorchis sinensis (12.3%), and other parasites (0.7-5.0%). Twenth-two (Puan
gun) and six (Sachon-gun) heterophyid egg positive cases were treated with
praziquantel, and adult flukes were collected from their diarrheic stools. A
total of 3,284 adult flukes of Heterophyes nocens was collected from all of the
22 patients treated in Puan-gun (3-778 individually), and other trematodes were
also collected from 2-15 patients: Pygidiopsis summa, Stellantchasmus falcalus.
Metagonimus yokogawai, M. miyatai, Stictodora fuscata. Heterophyopsis continua,
Acanthoparyphium kurogamo, and Gymnophalloides seoi. In Sachon-gun, M. yokogawai
(3,007 specimens), H. nocens (120), and S. falcatus (46) were collected from 5 of
6 treated patients, and H. continua and S. lari each from one patient. The
present study revealed that heterophyid flukes, especially H. nocens and M.
yokogawai, are prevalent in the southern and western coastal areas of Korea where
fresh and/or brackish water fishes are popularly eaten raw.
PMID- 9755587
TI - Discovery of Gymnophalloides seoi metacercariae in oysters from islands of the
West Sea known as the habitats of paleartic oystercatchers.
AB - An epidemiological survey was performed to know the infection status of oysters
with Gymnophalloides seoi metacercariae in 7 islands of the West Sea known as the
habitat of paleartic oystercatchers, Haematopus ostralegus osculans, in Korea.
The surveyed areas were Aphaedo (Shinan-gun, Chollanam-do), Jangjado, Sonyudo and
Munyodo (Okdo-myon, Kunsan-shi, Chollabuk-do), Yubudo (Changhang-up, Sochon-gun
Chungchongnam-do), and Polumdo and Chumoondo (Sodo-myon, Kangwha-gun. Inchonshi).
The oysters collected from Aphaedo, the known endemic focus, were examined
monthly from August 1995 to October 1996 for observation of any seasonal
variation of the metacercarial density. The average metacercarial burden was 761
2,077 by month, but the seasonal variation of the metacercarial density was not
obvious. A total of 54 metacercariae was detected in 63 oysters collected from
Yubudo. Out of 30 oysters from Sonyudo, 25 (83.3%) were infected with 1-66
metacercariae (12.6 in average). All of 50 oysters (100%) from Munyodo were
infected with 3-162 metacercariae (53.5 in average). Only 4 metacercariae were
detected in 100 oysters from Chumoondo. However, no metacercariae were found in
55 oysters from Jangjado and 50 oysters from Polumdo. From the above results, it
was confirmed that G. seoi is still highly prevalent in oysters from Aphaedo, and
several islands of the West Sea known as the habitats of paleartic oystercatchers
are new endemic areas of this fluke.
PMID- 9755588
TI - Infection kinetics and developmental biology of Cryptosporidium muris (strain
MCR) in Korean native kids and Corriedale lambs.
AB - A total of nine Korean native kids and two Corriedale lambs, 1-20 days old, were
each inoculated per os with a single dose of 2 x 10(7) oocysts of Cryptosporidium
muris (strain MCR) originated from mice to elucidate the kinetics and
developmental stages of the coccidium in small ruminants. Irrespective of host's
age, the prepatent period for both animals ranged from 19 to 35 days (28.1 days,
on the average) and the patent period 16-85 days (47.8 days), and the total
oocyst outputs showed enormous differences. Infection with greater numbers of
oocyst outputs was not ordinarily established by transmission experiments.
Oocysts discharged from the kids retained their infectivity by the mouse
titration method. The immunogenicity of the coccidium and oocyst reproduction
were proven by challenge infection and administration of prednisolone acetate,
respectively. All the developmental stages of the coccidium in parasitophorous
vacuoles were found by transmission electron microscopy in the pits of the
gastric glands of a kid inoculated with oocysts and then necropsied on day 44
postinoculation. It indicated the full course of the host-parasite relationship
in kids and lambs as well as mice.
PMID- 9755589
TI - Immunodiagnosis of clonorchiasis using a recombinant antigen.
AB - A cDNA expression library of Clonorchis sinensis adult worm was constructed, and
screened out immunologically. One clone, pBCs31, was selected in view of its
predominant reactivity with an experimentally infected rabbit serum. Recombinant
C. sinensis antigen with 28 kDa as a beta-galactosidase fusion protein produced
in Escherichia coli was identified by immunoblot analysis. The cloned gene was
composed of 16 copies of a 30 base pair repeat and an additional 320 bases. The
deduced amino acid sequence of the tandem repeat was AQPPKSGDGG. On RNA slot blot
analysis. C. sinensis adult worm RNA showed a positive reaction with the cloned
gene. Enzyme-linked immunosorbent assay using a purified recombinant antigen of
pBCs31 showed high specificity for diagnosis of clonorchiasis.
PMID- 9755591
TI - Neoplagioporus zacconis (Trematoda: Opecoelidae) from the intestine of the pale
chub, Zacco platypus, in Korea.
AB - Neoplagioporus zacconis (Yamaguti, 1934) (Trematoda: Opecoelidae) was found from
the intestine of the pale chub, Zacco platypus, for the first time in Korea. The
worms were characterized morphologically by oval body shape, bipartited seminal
vesicle, sinistrally located genital pore, and lobed ovary, and distinguished
from the two other species of Neoplagioporous by body shape and distribution of
vitelline follicles. The morphological characteristics, except the ovary, well
corresponded to those of the previous descriptions. The morphological difference
of the ovary was considered as a character of geographical phenotypic variation.
PMID- 9755590
TI - Changes in enzyme activity and expression of DHFR of Toxoplasma gondii by
antifolates.
AB - The responses to antifolates of Toxoplasma gondii were investigated by measuring
the dihydrofolate reductase (DHFR) activity, quantity of DHFR mRNA, and single
strand conformational polymorphism (SSCP) pattern. Pyrimethamine (PYM) and
methotrexate (MTX) were tested as antifolates. When T. gondii was treated with
PYM, the viability was decreased by the increasing concentration of PYM, DHFR
activity tended to increase as the passage proceeded, and the quantity of mRNA
expressed was also increased according to passages. The viability of T. gondii
was decreased by the increasing concentration of MTX, but it was maintained over
40% up to 100 microM MTX. DHFR activity was 77.4% in the 1st passage (1 microM).
82.2% in the 4th passage (10 microM), and 141.3% in the 7th passage (100 microM).
But no changes were detected in SSCP pattern of T. gondii exposed to PYM and MTX,
both. These results suggested that the response of T. gondii to PYM was regulated
by transcriptional level and that, in MTX, the viability of T. gondii was derived
from increasing DHFR activity.
PMID- 9755592
TI - Immunosuppressive effect of Cryptosporidium baileyi infection on vaccination
against avian infectious bronchitis in chicks.
AB - Two-day-old commercial chicks were inoculated orally with 2 x 10(6) oocysts of
Cryptosporidium baileyi and vaccinated with 10(3.5) EID50/head of a commercially
available avian infectious bronchitis (IB) live virus vaccine at 4 and 14 days
following inoculation. Chicks infected with C. baileyi were shown to have an
immunosuppressive effect on IB virus. It is concluded that infection with the
protozoon in early life may increase their susceptibility to IB.
PMID- 9755593
TI - Genetic variance of Trichomonas vaginalis isolates by Southern hybridization.
AB - In the present study, genomic DNAs were purified from Korean isolates (KT8, KT6,
KT-Kim and KT-Lee) and foreign strains (CDC85, IR78 and NYH 286) of Trichomonas
vaginalis, and hybridized with a probe based on the repetitive sequence cloned
from T. vaginalis to observe the genetic differences. By Southern hybridization,
all isolates of T. vaginalis except the NYH286 strain had 11 bands. Therefore all
isolates examined were distinguishable into 3 groups according to their banding
patterns; i) KT8, KT6 and KT-Kim isolates had 11 identical bands such as 1 kb,
1.2 kb, 1.6 kb, 1.9 kb, 2.3 kb, 2.7 kb, 3.2 kb, 3.4 kb, 3.8 kb, 4.9 kb and 6.0
kb. ii) The metronidazole-resistant IR78 strain had the same bands as KT-Lee
isolate at bands of 1 kb, 1.2 kb, 1.6 kb, 1.8 kb, 2.1 kb, 2.5 kb, 2.7 kb, 2.9 kb,
3.4 kb, 5.0 kb and 6.0 kb. Bands of CDC85, metronidazole-resistant strain, were
similar to those of IR78 and KT-Lee, except that 3.2 kb replaced 2.9 kb. iii)
NYH286 particularly had 12 bands and band patterns were similar to IR78 with a
few exceptions as follows: i) 6.2 kb in place of 6.0 kb, ii) 2.0 kb and 2.2 kb
instead of 2.1 kb. Through the results obtained, genetic variance of T. vaginalis
isolates was demonstrated by Southern hybridization.
PMID- 9755594
TI - Biological roles of vascular endothelial cell in various pathologic processes.
PMID- 9755595
TI - [Effect of phenylephrine, endothelin and angiotensin II on reperfusion
arrhythmias. A role for Na+/H+ exchanger activation via protein kinase C].
AB - Stimulation of receptors for alpha 1-adrenergic agonist, endothelin (ET) and
angiotensin II (AT) activates the cardiac sarcolemmal Na+/H+ exchanger (NHE),
perhaps via protein kinase C(PKC)-mediated pathway(s). We tested for the ability
of these extracellular stimuli to exacerbate reperfusion arrhythmias and for the
possible role of NHE activation and PKC in such phenomena. Isolated rat hearts (n
= 12/group) were subjected to dual coronary perfusion. After 15 min of aerobic
perfusion, flow to the left coronary bed was reduced to 5% of basal values for 12
min, and the same bed was then reperfused for 5 min. An alpha 1-adrenergic
agonist phenylephrine (PE) at 1 or 10 mumol/L, ET at 0.5 or 5nmol/L or AT at 1 or
10mumol/L was infused selectively into the left coronary bed during 12 min of
regional low flow ischemia. The incidence of reperfusion-induced ventricular
fibrillation (VF) was increased from 17% in control to 33% and 75%* with 1 and 10
mumol/L PE(*p < 0.05 vs control) from 8% in control to 8% and 12% with 0.5 and 5
nmol/L of ET. However, AT had no effect. The selective NHE inhibitor NOE642 at 1
mumol/L, infused concomitantly with 10 mumol/L PE, reversed the proarrhythmic
effects of PE; VF incidence was reduced from 67% to 8%*. However, glibenclamide
(a blocker for the ATP-sensitive K+ channel) at 1 mumol/L did not affect the
proarrhythmic effects of PE. Infusion of a specific PKC inhibitor GF109203X(GF)
at 30 or 300 nmol/L, starting from 5 min before ischemia and maintained
throughout ischemia concomitantly with 10 mumol/L of PE, was partially effective
in reducing VF incidence; which reduced from 75% in control to 42% with 300
nmol/L of GF. These results suggest that, in rat hearts subjected to regional low
flow ischemia and reperfusion, stimulation of alpha 1-adrenergic receptor can
exacerbate reperfusion-induced VF, whose mechanism(s) may involve NHE activation.
Moreover, PKC activation does not appear to be the sole signaling mechanism for
this phenomenon.
PMID- 9755597
TI - Role of dorsal neck proprioceptive inputs to vestibular compensation in humans.
AB - To investigate the role of cervical proprioceptive inputs in the process of
vestibular compensation, we performed static posturography in patients with acute
and compensated unilateral vestibular dysfunction, by applying vibratory
stimulation to the dorsal neck muscles. Neck vibration induced disequilibrium in
both groups of patients, but was more pronounced in the compensated patients.
These results indicate that manipulation of the neck afferents causes
discompensation in subjects whose vestibular dysfunction has already been
compensated by multisensory inputs including neck afferents.
PMID- 9755596
TI - Effects of serum of streptozotocin-induced diabetic rats on vascular smooth
muscle cell growth in vitro.
AB - This study was undertaken to biochemically and immunohistochemically clarify the
expression of basic fibroblast growth factor (bFGF), insulin-like growth factor-I
(IGF-I), fibroblast growth factor receptor (bFGFR), insulin-like growth factor-I
receptor (IGF-IR) and vascular smooth muscle cell (VSMC) growth by using
Streptozotocin (STZ) treated rat serum. At 12, 16, 24 weeks after STZ
administration, blood sera were collected from STZ treated rats. STZ treated rat
sera promoted much more vascular smooth muscle cel proliferation than control
sera. IGF-I was increased in the sera of STZ treated rats. Also according to
western blot analysis, the protein synthesis of bFGFR and IGF-IR in the VSMCs was
increased in STZ treated rat sera. Immunohistochemically, bFGF, IGF-I and their
receptors were much more localized in VSMCs in STZ treated rat sera than in
control sera. These results suggest that the growth factors and their receptors
produced in VSMCs in STZ treated rat serum may contribute to the proliferation of
VSMCs in autocrine and paracrine patterns.
PMID- 9755598
TI - Veins of the lumbar spinal ganglia in human adults and fetuses.
AB - To obtain a fundamental knowledge of the morphological relationship between nerve
root symptoms and circulatory disorders, the distribution pattern of the veins in
the lumbar spinal ganglia from the first to fifth vertebrae was investigated in 5
adult human cadavers (mean age 69.6 years) and 5 human fetuses (mean age 6.6
months). The following results were obtained: 1) In the adults the veins
perforating from the outer surface of the fifth lumbar spinal ganglion were
smaller in number than those perforating from the first to fourth ganglia. In
contrast, in the fetuses the number of such veins was increased in the lower
lumbar spinal ganglia. In each of the ganglia, the number of veins emerging
through the dorsal side was much higher than the number perforating from the
outer surface of the ventral sides. The veins perforating through the outer
surface of the ganglion formed weak venous networks (periganglionic venous
plexus) surrounding the dorsal ramus of the spinal nerve. 2) The veins
communicating with the tributaries from the periganglionic venous plexus were
classified into three types. Type 1 veins flowed into the intervertebral veins
(the frequency ranged from 9.2 to 18.2 in the adults and from 22.4 to 37.0 in the
fetuses). Type 2 veins coursed in the spinal cord along the dorsal root fibers
and penetrated the dura mater on the way (the frequency ranged from 0.4 to 4.8 in
the adults and from 1.2 to 2.2 in the fetuses). Type 3 veins opened directly into
the internal vertebral plexus (the frequency ranged from 0.4 to 1.8 in the adults
and from 0 to 0.4 in the fetuses). Type 1 veins were the most frequent among the
three types of veins in both adults and fetuses. Few type 3 veins were observed
in either group. 3) In the first and second lumbar vertebrae in the adults, three
quarters of each spinal ganglion was situated in the vertebral canal. In the
lower lumbar region (L3-L5), three quarters of each spinal ganglion lay on the
outside of the vertebral canal. In the fetuses, approximately one half to three
quarters of each lumbar spinal ganglion was located in the vertebral canal.
PMID- 9755599
TI - Combination of low back pain and previous low back pain and shoulder stiffness in
construction employees.
AB - A postal questionnaire for the prevalence of low back pain was studied with
relevance to stiffness of that shoulder and a history of low back disorders in
construction employees. The percentage of clerical employees with low back pain
was 31.3% and of field workers was 30.3%. Odds ratios representing a relative
risk factor for low back pain relating to each age group showed 2.35 in the
clerical and 2.10 in the field workers at the age of 30-34 years, and 3.34 and
2.58 at the age of 35-39 years, respectively. In the persons with positive
previous low back pain, the prevalence rate of low back pain was 52.6% in the
clerical, and 50.2% in the field workers. Odds ratios for low back pain relating
to previous low back pain significantly exceeded unity for the clerical employees
(OR = 9.53) and the field workers (OR = 10.28), compared to those without a
history of previous low back pain. The incidence of stiffness of the shoulder was
48.2% in the clerical and 45.2% in the field workers, and the prevalence rate of
low back pain among those with stiffness of the shoulder was 68.5% in the
clerical and 65.8% in the field workers. Odds ratio were 3.03 in both groups.
Among each age group, the prevalence rate of stiffness of the shoulder with low
back pain increased gradually to a maximum in the 45-49 age group of 19%, and
then dropped. In those with a history of low back pain and/or stiffness of the
shoulder, the prevalence of low back pain showed significantly greater value than
other risk factors.
PMID- 9755600
TI - Successful treatment of anomalous origin of the left coronary artery from the
pulmonary artery in a 5-week-old male infant.
AB - A 5-week-old male infant who was referred to our hospital because of tachypnea
and poor feeding. An electrocardiogram showed a deep Q wave in lead aVL, negative
T waves in leads I, II, III, aVF and V6 and a positive T wave in VL.
Echocardiography revealed severely impaired left ventricular function.
Aortography confirmed with a diagnosis of anomalous origin of the left coronary
artery from the pulmonary artery (ALCAPA). Takeuchi's procedure was performed and
the patient maintained postoperatively on assisted circulation for 7 hours even
though sternal closure delayed until 7 days post operatively. His left
ventricular function showed and marked improvement gradually.
PMID- 9755601
TI - Treatment of posterior skull base tumors.
AB - Surgery for posterior skull base tumors may be associated with high morbidity and
mortality because of the complex anatomy, irregular bony topography, and vital
neurovascular structures in this region. We experienced three benign posterior
skull base tumors. These were petroclival and foramen magnum meningiomas and a
jugular formen neurinoma. Three dimensional computed tomography (3 D-CT) in
addition to the conventional CT, magnetic resonance imaging (MRI), and cerebral
angiography were performed preoperatively. Preoperative embolizations for the
tumors were also done, and intraoperative neurophysiological monitorings were
performed. The tumors could be subtotally removed with no damage to the
brainstem, cranial nerves, and vessels. No newly developed postoperative
neurological symptoms were observed. As to the remaining tumors, gamma knife
(gamma-knife) therapy was planned. 3 D-CT was very useful in the preoperative
evaluation of the surgical approach, and the intraoperative neurophysiological
monitoring was considered to be necessary to prevent permanent damage. gamma
knife after direct approach was recommended for the benign posterior skull base
tumors.
PMID- 9755602
TI - [Endocrine surgery. Diagnosis and therapy for thyroid malignant lymphoma].
PMID- 9755603
TI - [Osteoporosis and the prevention of age-related fractures].
PMID- 9755604
TI - [Removal of bile duct stones by endoscopic papillary balloon dilatation (EPBD) of
papilla of Vater].
PMID- 9755605
TI - [A case of bilateral paramedian thalamic infarct syndrome that presented with
consciousness disturbance and vertical gaze palsy].
PMID- 9755606
TI - [The basic concepts of public health].
PMID- 9755607
TI - [Health from human ecology view point].
PMID- 9755608
TI - [Home care service utilization by severely mentally and physically handicapped
persons].
AB - PURPOSE: To investigate the utilization of in-home services by severely mentally
and physically handicapped persons at home in order to clarify the vital factors
associated with the services. METHODS: Questionnaires were delivered to 174
severely mentally and physically handicapped persons who were registered with 8
institutions in Tokyo and Kanagawa prefecture through each institution. One
hundred and thirteen respondents among them were the subjects of this study. As a
conceptual model Andersen's model was adopted. RESULTS: (1) The age of subjects
varied from 2 to 50. There were no subjects between the age of 7 to 17. The mean
functional handicap severity score (SCORE) was 5.8 +/- 8.4 standard deviation.
Ninety seven percent of main caregivers were mothers, even among the aged. (2)
Over 1/2 of the subjects reported having utilized institutional services. On the
other hand the percentage for visiting nurse service (VNS) and home help services
were 28.3% and 7.7% respectively. (3) Subject who used V.N.S. had significantly
higher SCORES and higher luck of health of caregivers. Caregivers utilized V.N.S.
as a substitute to reduce their burden in activities care at home. On the other
hand, users of institutional services showed high scores in difficulties with
daily help and perceived difficulties with medical treatments: it showed that
they sought institutional care to reduce there careburden. (4) Total number of
used by each client for in-home service was explained only by both difficulties
of daily help and SCORE from multiple regression analysis. CONCLUSION: Users of
visiting nursing service expect highquality care based on current medical
knowledge and also with the aim of caregiver's health. With the increasing age of
caregivers it appears to be important to enhance visiting nurse services, reduce
the caregiver burden, and provide active support of home care for the
handicapped.
PMID- 9755609
TI - [Factors influencing grief due to bereavement among elderly widows and widowers].
AB - OBJECTIVES: To identify the factors that influence the grief of bereaved elderly
people due to the death of a spouse. METHOD: Subjects consisted of 172 widows and
widowers (137 females, 35 males) aged 60 or older who experienced bereavement of
a spouse in the last three years. Between August 1994 and October 1996, the
subjects were interviewed using a semi-structured questionnaire and data was also
obtained from self-report measures which were returned by mail. A questionnaire
consisting of 26 items was prepared based on the theories of Parkes and Deeken.
These responses were classified into 4 categories (sensory paralysis, deep
attachment and protest, disintegration, reconstruction) and analysis was made by
these categories. The time course of the grief was evaluated at 1 week, 49 days
and 1 year after the death of the spouse and the time of survey. RESULTS: (1) Of
the 172 subjects, general health was graded as poor or slightly poor in 33.6%,
67.4% cared for their spouse during medical treatment; and the average GDS
depression score was 5.85 (SD = 3.50). (2) With respect to anticipated grief,
while their spouses were under medical treatment, more than 50% of the subjects
were thinking "I will do Whatever I can to cope". (3) Change in grief response
over time: For "sensory paralysis", "I have done whatever I can" rated the
highest at 3 points or more on a scale of 4, from immediately after the spouse's
death to the present. For "deep attachment and protest", deep attachment
including "always thinking of the lost one" marked higher (3.4 points immediately
after death to 2.9 at present) than protest. For "disintegration", "nobody
understands what I feel" rated the highest (2.6-2.9 points). For
"reconstruction", the subjects gradually accepted the death as "unavoidable" and
had started to adapt. (4) Factors that significantly influenced grief were the
subject's health condition, whether the subject had been notified of the name of
the disease or given a prognosis; whether subject provided care for the spouse
and GDS depression score. CONCLUSION: Sufficient anticipated grief resulted in a
feeling of achievement in the sensory paralysis aspect of the grief response and
in a long lasting feeling of deep attachment as loneliness and solitude.
Disintegration was largely related to depression according to GDS score. Grief
was less deeply felt when the subject was healthy, had been informed of the name
of the spouse's disease, and had cared for the spouse during medical treatment
before bereavement.
PMID- 9755610
TI - [Geographical distribution of medical expenditure for the aged insured by
National Health Insurance in secondary medical care areas in Japan].
AB - PURPOSES: To determine what factors affect medical expenditure for the aged
insured by the National Health Insurance among secondary medical care areas.
METHOD: The original data of municipalities were combined and converted into the
data of secondary medical areas. The original data included medical expenditure
of the aged in 1994, medical supply factors per 100,000 population (numbers of
doctors, numbers of general beds in hospitals, numbers of clinics, etc.) and
socio-economic factors (income, proportion of employees for three sectors of
industries, population density, average size of family, etc.). Medical
expenditures for inpatients and outpatients were used separately as independent
variables. The medical supply and socio-economic factors have been used as
dependent variables. Multiple regression models were applied to clarify the
differences in the contributing factors between inpatient and outpatient.
RESULTS: 1. The maximum inpatient and outpatient medical expenditures for the
aged are respectively 4 times and 2.6 times more expensive than minimum
expenditures among secondary medical care areas. 2. The numbers of beds, income
per capita, numbers of doctor, average size of family, proportion of employees
for third level industry and income accounted for 57.4% of variance in inpatient
medical expenditure of the aged. 3. The proportion of employees for first level
industry, the numbers of beds and average members of family accounted for 21.4%
of variance in outpatient medical expenditure of the aged. 4. Medical expenditure
for inpatients related with medical supply and socioeconomic factors differently
from that of outpatients.
PMID- 9755611
TI - [The relation between platelet aggregation and constitutional and lifestyle
variables in two Japanese communities].
AB - To investigate the contribution of the platelet aggregation in the development of
cardiovascular diseases, we examined the relation of constitutional and lifestyle
variables with platelet aggregation for a total of 306 males aged 50 to 70 in
Ikawa town, Akita prefecture (n = 163) and Noichi town, Kochi prefecture (n =
143). The examination of platelet aggregation was completed within 3 hours of
obtaining blood samples. We used ADP (Adenosine 5'-diphosphate) as an agonist and
obtained PATI (the platelet aggregatory threshold index) by nephelometry.
Platelet count, mean platelet volume, white blood cell count, serum fatty acid
compositions were also examined and dietary intake of fish, seafood and soy bean
foods were inquired using one-week dietary records. PATI indicated a logarithmic
normal distribution in both Ikawa and Noichi. The mean of logarithmic transformed
PATI (log PATI) was higher in Ikawa than in Noichi. Thus platelet aggregation was
lower in Ikawa than in Noichi. According to multiple regression analysis, age,
platelet count in platelet rich plasma, mean platelet volume in platelet rich
plasma, and white blood cell count were inversely associated with log PATI. Serum
arachidonic acid composition tended to be inversely related with log PATI. Serum
n3-polyunsaturated fatty acid composition was positively related with log PATI,
and log gamma-GTP tended to be positively associated with log PATI. Soy protein
intake and cigarette smoking showed no consistent associations with log PATI.
This cross-sectional study suggests that serum n3-polyunsaturated fatty acid, and
gamma-GTP, as an index of alcohol intake, reduce platelet aggregation while age,
white blood cell count, platelet count, mean platelet volume, and serum
arachidonic acid raise platelet aggregation.
PMID- 9755612
TI - [Survival and disability in stroke by stroke subtype based on computed
tomographic findings in three rural Japanese communities].
AB - PURPOSE: We conducted an epidemiological study of survival and disability in
stroke in three Japanese communities to seek community strategies for improvement
in survival and disability. METHODS: A total of 297 first-ever strokes were
identified between 1988 and 1992 in three rural communities (total population =
47,000) located in Akita and Ibaraki. We analyzed survival rates and activity of
daily living by sex, age-group and stroke subtypes. Successful review of computed
tomography (CT) for 84 percent of the strokes (249 out of 297) was possible and
the data were used for subtype analyses. RESULTS: For all strokes (n = 297)
survival rates were 85% for 30 day, 70% for one year, 62% for three year. The
rates tended to be lower in women than in men. The rates were lowest in ages less
than 60 at thirty day, and in ages 80 and older at the end of the first and third
year. Intracerebral hemorrhage with ventricular rupture, subarachnoid hemorrhage
and cortical cerebral infarction had lower survival rates than intracerebral
hemorrhage without ventricular rupture and lacunar infarction. Based on Cox's
proportional hazard model, risk ratio for death was 2.07 in ages 70-79, and 3.80
in ages 80 and older compared with ages 60-69. The risk ratio was 3.46 for
intracerebral hemorrhage with ventricular rupture, 3.38 for subarachnoid
hemorrhage and 2.46 for cortical cerebral infarction compared with lacunar
infarction. The proportion of stroke survivors who need assistance from others in
the first and third years tended to be higher in women than in men. The
proportion was higher in older patients than in the younger, and higher for
intracerebral hemorrhage with ventricular rupture and cortical cerebral
infarction than in other subtypes of stroke. From logistic regression analysis,
the odds ratio for disability in the first year was 6.55 for ages 80 and older
compared with ages 60-69. The odds ratio was 5.61 for intracerebral hemorrhage
with ventricular rupture, 4.53 for cortical cerebral infarction compared with
lacunar infarction. In the third year the odds ratio was significant for ages 70
79, and decreased for intracerebral hemorrhage with ventricular rupture (odds
ratio = 2.98), and increased for cortical cerebral infarction (odds ratio =
6.06). CONCLUSIONS: Survival and disability in stroke depended on age and stroke
subtypes. Even after age adjustment, stroke subtypes with large cerebral
involvement had worse prognosis than stroke subtypes. Community-based
hypertension control programs are important to prevent any subtypes of stroke.
Stroke subtypes as well as age should be taken into account to develop effective
care and medical treatments for strokes.
PMID- 9755613
TI - [Postpartum depression and social support].
AB - OBJECTIVES: To ascertain the state of a mother's depression three months after
childbirth and to what sort of or to whose social support it is related. METHOD:
In October 1993, a questionnaire survey was conducted on the attributes, state of
depression by Zung Self-rating Depression Scale, and social support of 300
mothers who received health examinations of their 3 to 4 months' old infants at
five health centers in Tokyo. Relationship between depression and social support
of 256 mothers (rate of valid answer 85.3%) was examined by one-way analysis of
variance, Pearson's product moment correlation coefficient and multiple
regression analysis. RESULTS: The depression score averaged 37.3 points, with 73
persons (28.5%) scoring 40 to 47 points (light) and 27 persons (10.5%) scoring 48
or more points (medium level or higher). The following were the variables which
individually showed a significant relationship to the depression score after
controlling for age, education, number of children, type of family, and whether
or not the mother was working: The emotional support score from the husband and
his parents, such as the frequency in which the husband "listened to the mother's
worries and anxieties" "was attentive or considerate to the mother" and "helped
in feeding the child", the frequency in which the husband's parents "could be
consulted on worries the mother had about childbirth, child care and child
development" and "nursed and played with the child". It was found that the better
the state of such support, the less the state of depression. On the other hand,
support from the mother's parents, neighbors, and friends had no bearing on
depression. CONCLUSION: The level of depression of the surveyed group was the
same as that of the general female public. Postpartum depression was related to
emotional support from the husband and emotional and practical support from the
husband's parents. Therefore, from the aspect of preventing depression, we
believe it is important that, firstly, the mother and family should understand
the importance of support and improve the support by the family, and, secondly,
the mother herself should improve her ability to cope.
PMID- 9755614
TI - [Combination care of a patient with Joseph's disease local community].
PMID- 9755615
TI - [Primary health care in Thailand with community participation special reference
to Japanese assistance].
AB - The international health cooperation of Japan for developing countries has been
mostly concentrated on matters such as improvement of hygienic environment,
prevention of tropical infectious diseases, establishment of hospitals with
modern medical instruments and devices, and dispatch of medical experts. PHC
(Primary Health Care) activities based on voluntary participation of local
inhabitants in developing countries have been largely neglected. In the field of
health and medical care, sufficient effect may not be achieved unless the local
health activity is based on voluntary participation of the inhabitants. The
introduction of highly advanced modern medical techniques may be beneficial to
some of the inhabitants, while most of the local inhabitants may not have the
chance to receive such benefits, and additionally it is difficult to propagate
modern medical care and technique widely to rural areas in Thailand. In Thailand,
PHC activity based on community participation was started in 1985, with the
following three items as main themes: (1) Training of Village Health Volunteers
(VHV) and Village Health Communicators (VHC), and development of their
activities. (2) Establishment and operation of Health Centers. (3) Establishment
and operation of Drug Cooperative System (DC). Earlier, as one of PHC activities
developed by Japan, "Thailand Local Health Activity Improvement Project" based on
the program of Thailand-Japan Partnership was initiated in 1976 in rural areas of
Chanthaburi Prefecture. From 1982, third country training programs have been
carried out by Japan International Cooperation Agency (JICA). Since 10 years have
elapsed the initiation of PHC activity in rural areas in Thailand under the
cooperation of the Governments of Thailand and Japan, it seems to be time to
reconsider and study again how PHC activity should be developed in future based
on candid evaluation of achievements and results.
PMID- 9755616
TI - [Physician demand projection models in U.S.A].
PMID- 9755617
TI - [Salt intake in young children].
AB - Among adult Finns salt intake is about twice as high as the recommended levels
and almost five-fold greater than the physiological requirement. Information as
to salt intake in children has hitherto been sparse. Daily sodium intake among 1
5-year-olds was investigated in this study, and the foodstuffs from which it was
derived were identified. In all age groups, sodium intake was at least two-fold
greater than the Nordic recommendations, and among five-year-olds it exceeded the
recommended intake for adults. Approximately half of the sodium intake was found
to have derived from salt used in cooking. Levels of sodium derived by children
from dairy, meat and grain products were also relatively high. Sodium intake in
children after infancy merits greater attention than previously accorded it, as
permanent eating habits and taste preferences are already formed at this age, and
reasonable limits for salt intake should therefore be established during
childhood.
PMID- 9755618
TI - [PET as a tool in pharmacologic development].
AB - Positron emission tomography (PET) allows the in vivo recording of tracer
compounds with respect to anatomical distribution, time course and absolute
concentration. These features has proven of great value in drug development,
especially in the phase of early clinical trials. PET can be used to assess the
tissue kinetics of a new drug, or to evaluate a drugs interaction with a target
system and thereby aid in decisions regarding dosing regimes.
PMID- 9755619
TI - [Back pain--from the viewpoint of medical technology. Danish National Board of
Health].
AB - The appearance of various consensus reports, guidelines, Cochrane Centers, and
other evidence-based medicine initiatives during the past decade has resulted in
marked improvement in the rational utilisation of available knowledge of
attitudes toward the issue of low back pain (LBP). Moreover, owing to the ready
access to updated data bases, this knowledge has been disseminated with
incredible speed. In the spring of 1995, the Danish National Board of Health in
Denmark convinced a multidisciplinary team of back specialists to tailor data
available in the international reports for Danish needs. The article outlines the
findings of this team, the major recommendations being that providing information
is preferable to treatment, that patients should be encouraged to remain active,
that physical exercise should be kept up except during the acute phases, that
most episodes of LBP are to be considered life events rather than automatic
reasons to seek treatment, and that passive treatment should be minimised, though
manipulation may be helpful in the short term.
PMID- 9755620
TI - [Sciatica--diagnosis and surgical management].
AB - Sciatica (a term used synonymously with lumbar radiculopathy) is usually caused
by lumbar disc herniation or lumbar spinal stenosis. Mechanical compression of
nerve roots is a predominant factor, and decompression the surgical goal.
Emphasis should be placed on clinical identification of the nerve roots causing
the complaint. Although computed tomography (CT) and magnetic resonance imaging
(MRI) are the most important diagnostic tools used today, plain x-ray may be
required for correct identification of the lowest mobile segment, and the
functional myelography combined with CT may be required if lumbar spinal stenosis
is suspected, or if the clinical findings are unclear--especially if the patient
has already undergone surgery for sciatica. The proper selection for candidates
for surgery seems to be a more important determinant of successful outcome than
whether macro- or micro-surgery is used, or whether one or more segments are
operated upon (12, 13). Clear clinical identification of the roots affected and
corresponding pathological findings at imaging are the best predictors of
successful surgical outcome, an additional factor of positive predictive value
being psychosocial stability. Impaired fibrinolysis, occurring in smokers and in
the sedentary and obese, may be a negative predictive factor (10, 11). Published
findings suggest that, unlike the case with disc surgery (9), neither long
duration of symptoms nor long preoperative sick leave is associated with poor
outcome of surgery for spinal stenosis (14).
PMID- 9755621
TI - [Back pain. Experimental studies are successful].
AB - Recent experimental studies performed at the Dept of Orthopaedics at Gothenburg
University have systematically assessed the basic pathophysiological mechanisms
behind sciatica due to disc herniation. It has hereby been seen that the epidural
presence of nucleus pulposus may induce structural and functional injury of the
adjacent nerve roots similar in magnitude to those induced by mechanical
deformation. By increasing the knowledge of the substances and mechanisms leading
to this nucleus pulposus-induced nerve injury it may be assumed that sciatica to
a certain extent may be treated by specific pharmacologic agents in the future,
in combination with existing treatment modalities.
PMID- 9755622
TI - [Decentralized special training in pulmonary medicine. A project using
telemedicine].
AB - In arctic Norway, where there is a lack of specialists in pulmonary medicine two
postgraduate students, already qualified as specialists in internal medicine at
Tromso Regional Hospital, applied to continue their training at their respective
local hospitals. The regional hospital in Tromso has a long tradition of
telemedicine, with network links to local hospitals in the region, and is
equipped for interactive consultation and the bilateral transmission of x-rays
and video recordings, and digital transmission of x-rays. Accordingly, supported
by their supervisor, the two postgraduate students applied to the committee for
postgraduate education in pulmonary medicine to have a year's work at their
respective local hospitals, supervised via the telemedicine facilities, accepted
as equivalent to a six-month module of the normal syllabus. The project was
approved and executed as planned. The registrars, who were responsible for
pulmonary service at their local hospitals, served four days a month at the
regional hospital, and their supervisor visited the local hospitals one day each
month. All internal education at the regional hospital was made available by
means of a weekly interactive televised link-up, x-rays being displayed on screen
as transmitted digitally; bronchoscopies were shown by video, and ad hoc
tutorials arranged as needed. Evaluated by the national committee, the project
was found satisfactory, and the registrars were duly qualified.
PMID- 9755623
TI - [Decisions about life and death. An empirical study of the position of Danish
physicians concerning end-of-life decisions].
AB - In a postal questionnaire investigation of experiences and attitudes concerning
end-of-life decisions among Danish physicians, most of the respondents reported
having made decisions involving the hastening of a patient's death, and
considered this acceptable. Such decisions were more frequent, and were
considered ethically more acceptable, when made with the patient's informed
consent than without. Of the respondents, two per cent had participated in
assisted suicide, and five per cent had administered a lethal injection at the
patient's request, practices considered ethically acceptable by 37 per cent and
34 per cent, respectively, of the respondents. The most frequently cited reasons
for opposing such practices were double effect principle, the active
killing/allowed-death distinction, and the sanctity of life; and the most
frequently cited justifications were respect for the patient's autonomy, the
avoidance of unnecessary suffering, and the patient's right to a death with
dignity.
PMID- 9755624
TI - [Feto-maternal transfusion following cordocentesis].
AB - Invasive intrauterine diagnostic procedures may be followed by feto-maternal
transfusion. The authors studied the feto-maternal transfusion after
cordocentesis. 199 women underwent fetal umbilical cord blood sampling for fetal
karyotyping in weeks 15-26. Maternal serum alpha-fetoprotein level was measured
before and after the procedure. The data were statistically analysed by multiple
regression analysis and the paired and unpaired Student's t-tests. Twenty percent
of more maternal serum alpha-fetoprotein level increase was observed in 73
(36.7%) women. Maximum feto-maternal transfusion was 0.684 ml. The average feto
maternal transfusion was 0.045 ml. No fetal exsanguination was observed. Positive
correlation was found between bleeding time after cordocentesis (p = 0.0171) and
feto-maternal transfusion as well as the duration of the procedure (p = 0.0275)
and feto-maternal transfusion. Negative correlation was found between the amount
of fetal blood sample and feto-maternal transfusion (p = 0.0431). The puncture
site also influenced feto-maternal transfusion. If the cordocentesis has been
performed at the insertion of the cord the feto-maternal transfusion was less
than at the free floating umbilical cord (p = 0.0293). Higher feto-maternal
transfusion was seen more often after transplacental cordocentesis (p = 0.002).
These data suggest that fetomaternal transfusion in the indicator of the
difficulty of the procedure.
PMID- 9755625
TI - [Food allergy in patients with respiratory allergy. Diagnostic possibilities and
problems].
AB - In the past two years the authors examined 28 patients with abdominal complaints
and allergic respiratory symptoms. Detailed internal, gastroenterological,
allergological examinations were made. METHODS: 1 skin Prick-test (SPT) with
inhalative and nutritive panel 2. measuring of food-specific (gliadin, alpha
lactalbumin beta-lactoglobulin, ovalbumin) IgG-antibody level detecting with
ELISA method, 3. leukocyte migration inhibition (LMI) test against the same
foodstuffs, 4. histological examination of the stomach and the duodenum
especially for mucosal mastocytes (MMCs). RESULTS: 1. SPT was positive in 23/28
patients for inhalative, but in the 5 cases we did not identify any inhalative
allergen. The SPT for the main foodstuffs were positive in 18 patients while in 3
other patients there was urtica only for the other antigens. 2. The food-specific
IgG-antibody level was increased in 18/27 patients against one or more antigens.
The SPTs and the antibody determination showed identity in 8/18 cases. 3. The LMI
tests were positive against one or more main food-products in 23/27 cases. There
was common positivity in respect of antigens (between LMI test and antibody
identification) in 17 cases. Pathological immunological reactions were presented
against the same main foodstuffs with at least two methods for flour in 11, for
egg in 10 and for milk in 12 patients. Endoscopic examinations were performed in
27 cases. The number of the MMCs were increased in 22/27 patients. After a
specific elimination diet open-food challenges were performed and they confirmed
the results of the in vitro and in vivo examinations. CONCLUSION: It is common
that the respiratory allergic symptoms in atopic patients accompanied with food
allergy for the main foodstuffs caused not only more severe respiratory symptoms,
but abdominal complaints too. In respect to the many positive LMI tests the late
type hypersensitivity have important pathogenetical role in it. This three
methods together define well the main food-products, which can be antigens as
well. The examination of the MMCs supports the local disturbance in the
immunoregulatory system.
PMID- 9755626
TI - [Iodine deficiency in cardiovascular diseases].
AB - The thyroid hormone deficiency on cardiovascular function can be characterized
with decreased myocardial contractility and increased peripheral vascular
resistance as well as with the changes in lipid metabolism. 42 patients with
cardiovascular disease (mean age 65 +/- 13 yr, 16 males) were investigated if
iodine insufficiency can play a role as a risk factor for the cardiovascular
diseases. The patients were divided in 5 subgroups on the ground of the presence
of hypertension, congestive heart failure, cardiomyopathy, coronary disfunction
and arrhythmia. Urine iodine concentration (5.29 +/- 4.52 micrograms/dl) was
detected with Sandell-Kolthoff colorimetric reaction. The most decreased urine
iodine concentration was detected in the subgroups with arrhythmia and congestive
heart failure (4.7 +/- 4.94 micrograms/dl and 4.9 +/- 4.81 micrograms/dl,
respectively). An elevated TSH level was found by 3 patients (5.3 +/- 1.4 mlU/l).
An elevation in lipid metabolism (cholesterol, triglyceride) associated with all
subgroups without arrhythmia. In conclusion, the occurrence of iodine deficiency
in cardiovascular disease is frequent. Iodine supplementation might prevent the
worsing effect of iodine deficiency on cardiovascular disease.
PMID- 9755627
TI - [Polysomnography in the prevention of crib death].
AB - The authors stress the importance of polysomnography--a new electrophysiologic
method--in the prevention of SIDS (cot death). SIDS is the most important and
frequent cause of infant mortality between 1 and 12 months of age in western
countries (nowadays between 1-2/1000!). In Hungary the frequency is not so high.
In the last few years the incidence declined after the "back to sleep" campaigns,
but to reach further success, it is very important to seek the so called "risk"
babies. The unique cause of cot death is not yet understood exactly, but some
instability in respiration (mostly during the sleep) is one of the accepted
principal basic factors. The mentioned new method helps in choosing the SIDS risk
infants from the "normal" population, allows to examine their respiratory
irregularity or even disorders during the sleep and gives possibility for the
prevention of lethal apneas. The authors describe the details of the prevention
in case of abnormal polysomnography in their other publications.
PMID- 9755628
TI - [Pacemaker syndrome without a pacemaker].
AB - Circulatory consequences of cardiac arrhythmias are not always evident. Proper
interpretation of the clinical symptoms in certain cases requires assessment of
the patients' other hemodynamic characteristics. The authors present the case of
a patient with left ventricular hypertrophy, who developed severe circulatory
failure at the time of artrioventricular dyssynchrony in association with
junctional rhythm. Analogy between the circulatory consequences of the junctional
rhythm and ventricular pacing was documented by hemodynamic measurements. The
patient was subsequently treated by implanting an atrioventricular pacemaker.
PMID- 9755629
TI - [Quo vadis "suprema lex"?].
PMID- 9755630
TI - [Computed tomographic angiography of the thoracic vessels: the method, initial
experience and outlook for its use].
AB - The paper presents the data available in the literature on computed tomographic
angiography and the first experience with it to study thoracic vessels. It
details the principles of spiral computed tomography and CT angiography.
Practical aspects of their implementation, as well as basic concepts are
outlined. It is concluded that CT angiography is promising in studying thoracic
vessels in various abnormalities.
PMID- 9755631
TI - [A comparative analysis of the immediate and late results of coronary balloon
angioplasty in bifurcation stenoses performed by the traditional method and by
the "2-guide" method].
AB - To evaluate the efficiency of balloon coronary angioplasty (BCA) for bifurcation
stenoses, which had been made by the two-guide method, the results of the
angioplasties were examined in 147 patients with coronary heart disease. BCA had
been performed routinely in 54 patients and by the two-guide method in 32. Sixty
one patients undergone angioplasty for nonbifurcation lesions served as a control
group. In the group of routine BCA procedure, poor results with residual stenosis
of the major vessel were seen in 13% of cases, the incidence of complication
(dissection of unfavourable types, thrombosis of the major vessel) was 29.6%. In
the two-guide BCA, these indices were 15.6 and 2%, respectively, the incidence of
restenosis was 46.9% and that of branch lesions was 6.3%. The findings have led
to the following conclusions that routine angioplasty of bifurcation stenoses
yields poor early and late results of dilatation of lateral branches. The use of
the two-guide method substantially reduces the risk of damage to a lateral
branch, improves immediate dilatation of the major vessel, yet fails to affect
the number of restenosis in the late period.
PMID- 9755632
TI - [The X-ray diagnosis of congenital absence of the pericardium].
AB - The X-ray signs of such a rare abnormality as the congenital absence of the
pericardium are presented. The results of examinations and follow-up of 4
patients with this abnormality are analyzed. The patients underwent X-ray,
echocardiographic studies, cardiac catheterization and angiography. The diagnosis
of the absence of pericardium was confirmed at surgery and in one case at
autopsy.
PMID- 9755633
TI - [The puncture and catheterization of the peripheral vessels using ultrasonic
scanning].
AB - Having many-year experience with angiographic interventions, the authors examined
the potentialities of ultrasonic angioscanning to monitor the implementation of
endovascular interventions (EVI). During the study, they developed an original
procedure of different EVI with intraoperative ultrasonic monitoring, refined the
ultrasonic semiotics of the procedure, achieved positive results in preventing
possible complications. The authors made indications for the procedure and
rational ways of its application more concrete. They provide evidence for that
the proposed procedure greatly facilitates the performance of different
intravascular procedures and reduces the time (or excludes) teleradioscopy, thus
lowering the radiation burden on the staff and the patient.
PMID- 9755634
TI - [Diagnostic catheterization and angiography in the examination of patients with
ischemic heart disease].
PMID- 9755635
TI - [Experience in using at a polyclinic the Siberia low-dose digital X-ray unit].
PMID- 9755636
TI - [Sarcoidosis of the respiratory organs: the problems of etiology and
pathogenesis, classification and X-ray diagnosis].
PMID- 9755637
TI - [The University of X-ray Laboratory Assistants. Lesson 5. Image contrast].
PMID- 9755638
TI - [Magnetic resonance tomography and angiography in the assessment of the status of
the kidneys and renal arteries in patients with renovascular hypertension].
PMID- 9755639
TI - Molecular mechanisms of programmed cell death.
AB - Programmed cell death and apoptosis have now been recognised as biological
phenomena which are of fundamental importance to the integrity of organisms. What
may have evolved as an altruistic defence against pathogen invasion in simple
organisms is now a major regulatory mechanism in the development and maintenance
of multi-cellular organisms. The classically defined morphological
characteristics of apoptosis are now accompanied by a plethora of information
regarding common biochemical and genetic mediators of programmed cell death. It
is apparent that life and death decisions are taken by individual cells based on
their interpretation of physiological signals, or their own self-assessment of
internal damage. The knowledge that cell death is a genetically regulated process
has highlighted an inherent potential for manipulation and offered new avenues
for research into several diseases, and also productivity improvements in the
biotechnology industry. This relatively "new frontier" in cell science has
undoubtedly widened our perspectives and may provide novel strategies to expedite
both medical and biotechnological research.
PMID- 9755640
TI - Measurement of apoptosis.
AB - The cell dying by apoptosis undergoes a sequence of morphological, biochemical,
and molecular changes which are characteristic, and often unique, to this mode of
cell death. Specific features of apoptotic cells resulting from these changes,
which serve as markers used to reveal the apoptotic mode of cell death and to
quantify the extent of apoptosis in cultures or in tissue, are reviewed. Analysis
of these features by flow or image cytometry is the most commonly used approach
to detect, quantify, and study various aspects of apoptosis. Flow or laser
scanning cytometry also offer all the advantages of rapid, accurate and
multiparametric measurements to investigate the biological processes associated
with cell death. Numerous methods have been developed to identify apoptotic and
necrotic cells, which are widely used in various disciplines, particularly in
oncology and immunology. The methods based on changes in cell morphology, plasma
membrane molecular structure and transport function, function of cell organelles,
DNA stability to denaturation and endonucleolytic DNA degradation are reviewed
and their applicability in the research laboratory and in the clinical setting is
discussed. The most common pitfalls and improper use of the methodology in
analysis of cell death and in data interpretation are also discussed.
PMID- 9755641
TI - The Bcl-2 gene family and apoptosis.
AB - Apoptosis, or programmed cell death, is an essential process for normal embryonic
development, maintaining homeostasis in adult tissues, and suppressing
carcinogenesis. The bcl-2 protein, discovered in association with follicular
lymphoma, plays a prominent role in controlling apoptosis and enhancing cell
survival in response to diverse apoptotic stimuli. The evolutionarily conserved
bcl-2 protein is now recognized as being a member of a family of related proteins
which can be categorized as death agonists or death antagonists. Progress in
defining the role of bcl-2 and its family members in regulating apoptosis is
rapidly advancing. This review describes, in detail, current bcl-2 family members
and the possible mechanisms of function which allow the bcl-2 family of proteins
to either promote or suppress cell death.
PMID- 9755642
TI - The role of caspases in apoptosis.
AB - The process of apoptosis, or programmed cell death, is fundamental during normal
development and homeostasis and aberrant apoptosis has been implicated in a
number of human diseases. The cellular machinery involved in the execution of
apoptosis includes a family of cysteine proteases termed caspases. Caspases
exhibit the rare substrate preference of cleavage C-terminal to aspartate
residues, a property shared only by the cytotoxic lymphocyte serine protease,
granzyme B. Experimental evidence demonstrates a vital role for caspase
activation in the apoptotic pathway, and, as such, caspases are a target for the
development of agents that can modulate their activity. This article reviews the
members of the caspase family and the role that each contributes to the execution
of cell death induced by apoptotic stimuli.
PMID- 9755643
TI - "Tissue" transglutaminase and apoptosis.
AB - In this paper we discuss the role of "tissue" transglutaminase (tTG) in
apoptosis. This enzyme by catalizing the Ca(2+)-dependent cross-linking of
intracellular proteins leads to the formation of the SDS-insoluble protein
scaffold in cells undergoing programmed cell death. These intracellular
structures confer resistance to mechanical and chemical attack to the
polipeptides involved in the linkages. tTG is induced during apoptosis, in fact,
tTG mRNA is transcripted as a consequence of apoptosis induction. Overexpression
of tTG in many cell lines enhances their susceptibility to apoptosis, indicating
a pivotal role for tTG in this process. In keeping with these findings
transfection of the human tTG complementary DNA in antisense orientation leads in
a pronounced decrease of both spontaneous as well as induced apoptosis.
Interestingly, the identification of the tTG substrate proteins in cells
undergoing apoptosis has evidenced that many of the tTG proteins are also
substrates of caspases.
PMID- 9755644
TI - Survival factors and apoptosis.
AB - This chapter will explore the role of survival factors in suppression of
apoptosis, and illustrate how survival signals play a critical role in the
survival of both normal and tumor cells. Survival factors necessary for the
development and maintenance of the nervous system and hemopoietic system will be
surveyed. This will be followed by a detailed discussion of the role of insulin
like growth factor I (IGF-I) and its receptor in suppression of apoptosis. The
importance of survival signals from the IGF-IR for development and tumorigenesis
will be discussed, and results of a mutational analysis of the receptor to assign
domains necessary for suppression of apoptosis will be summarized. Finally, a
discussion of the signal transduction pathways involved in survival factor
signaling will review the roles played by PI-3 kinase and AKT and speculate on
how activation of these kinases by survival factors might regulate the apoptotic
pathway.
PMID- 9755645
TI - Apoptosis and bioprocess technology.
AB - Optimisation of the production of biopharmaceuticals in animal cell lines has
become a key area of research. The identification of apoptosis as the major
mechanism of cell death during such processes has raised the importance of
studies of cell death when implementing culture optimisation strategies. In this
article we present an overview of the studies which have demonstrated the
induction of apoptosis during the cultivation of industrially important animal
cell lines. We also discuss studies which have shown that deprivation of factors
such as amino acids, glucose, serum and oxygen are potent inducers of apoptosis
in industrial cultures. The suppression of apoptosis under these conditions has
been demonstrated by a number of recent reports, and we describe ways in which
this knowledge may be applied in the development of novel solutions to some of
the technical problems associated with the development of successful large scale
culture process. The article concludes with a discussion of future directions for
apoptosis research in bioprocess technology.
PMID- 9755646
TI - The outcome of parent training using the behavior management flow chart with
mothers and their children with oppositional defiant disorder and attention
deficit hyperactivity disorder.
AB - The effects of parent training, using parameters established in the Behavior
Management Flow Chart, on mother behavior and on the disruptive behavior of eight
children who emitted behavior consistent with the diagnoses of both Oppositional
Defiant Disorder and Attention-Deficit Hyperactivity Disorder were evaluated.
There are important differences between the Behavior Management Flow Chart and
well-known parent-training programs that are based on the Hanf model. Parent
training was conducted within a multiple baseline design across children. Direct
observation of mother and child behavior, phone interviews, and standardized
rating scales showed that training improved parenting behavior, reduced maternal
stress, and reduced oppositional child behavior. A 6-month follow-up revealed
that parenting and child behavior remained stable. The results are comparable
with prior research on behavioral parent training for families that have children
with oppositional/hyperactive behavior.
PMID- 9755647
TI - The effects of noncontingent and contingent attention for self-injury, manding,
and collateral responses.
AB - To date, most functional analysis studies have focused on the effects of
treatment contingencies on specific targeted aberrant and alternative responses.
In the current investigation, the main and collateral effects of the assessment
and treatment of attention-maintained self-injury were assessed. Specifically, we
evaluated the effects of noncontingent and contingent social attention on four
categories of behavior: self-injury, a novel mand, preexisting prosocial
responses (e.g., babbling and reaching out), and other aberrant responses (i.e.,
aggression and destruction). Results suggested that self-injury, prosocial
responses, and other aberrant behaviors were within the same functional response
class. Possible impact of these results when selecting mands for functional
communication training is discussed.
PMID- 9755648
TI - Evaluating outpatient behavior therapy of sex offenders. A pretest-posttest
study.
AB - This study compared the entrance and exit scores of 16 patients completing
treatment at the Highland Institute for Behavioral Change (HIBC), an outpatient
program specializing in the behavioral treatment of sex offenders. Outcome
measures included the Minnesota Multiphasic Personality Inventory (MMPI), the
Multiphasic Sexual Inventory, and recidivism (rearrest record) posttreatment.
Statistically significant and clinical improvements were obtained on a number of
these measures. One of the 16 graduates reoffended during the average follow-up
period of 26 months (he is now incarcerated). These data are supportive of the
contention that outpatient behavior therapy can be effective in reducing deviant
sexual arousal and in enhancing appropriate consensual sexual behavior.
PMID- 9755649
TI - A supported relationships intervention to increase the social integration of
persons with traumatic brain injuries.
AB - A supported relationships intervention was used to increase the integrated social
contacts (ISCs) of 3 persons with traumatic brain injury (TBI) who were each
matched with 4 community participants. The intervention consisted of asking
participants to meet with their matched counterpart to engage in leisure
activities once per week for 4 weeks. Additionally, community participants were
provided with a brief training session on TBI, were given specific suggestions on
interacting with the persons with TBI with whom they were matched, and received
weekly phone calls from the researcher. Frequency of ISCs were analyzed with a
multiple baseline design across participants. All 3 participants with TBI
increased the frequency of ISCs after implementation of the supported
relationships intervention and continued to experience more than baseline levels
of ISCs during 8 weeks of follow-up. These data suggest that social integration
can be enhanced with a procedure requiring limited staff intervention.
PMID- 9755650
TI - Use of noncontingent reinforcement in the treatment of challenging behavior. A
review and clinical guide.
AB - Recently, noncontingent reinforcement (NCR) has been used to reduce challenging
behavior in persons with developmental disabilities. In this context, NCR
involves reinforcement on a fixed-time schedule irrespective of behavior. The
present article reviews studies involving NCR for the treatment of challenging
behavior. Based on this review, a clinical guide for the implementation of NCR is
delineated. NCR appears to depend on ensuring that reinforcement matches the
function of the challenging behavior. Initially, noncontingent reinforcement
should be provided on a continuous basis. The schedule can then be faded from
continuous reinforcement to a more appropriate level in a number of ways. NCR can
also be combined with additional educationally oriented interventions to promote
skill development. Given its ease of implementation and other potential
advantages, NCR would appear particularly relevant for applied settings. The
clinical guide may offer some assistance to practitioners.
PMID- 9755651
TI - Staff attitudes that impede the implementation of behavioral treatment programs.
AB - Staff who have negative attitudes about behavioral treatments are less likely to
implement them. Previous research suggests that negative attitudes are associated
with staff burnout and perceived collegial support. A path analysis is conducted
in this study to determine the direction of these effects. Ninety staff members
who work in treatment programs for severely mentally ill adults completed
measures of attitudes about behavior therapy, experience with behavior therapy,
burnout, and collegial support. Results of the path analysis yielded a model with
good fit that confirmed our hypotheses; namely, burnout leads to negative
attitudes and experience with behavior therapy yields positive attitudes.
Insufficient collegial support leads to negative attitudes through burnout.
Implications of these findings for improving the use of behavior treatments in
real-world programs are discussed.
PMID- 9755652
TI - Behavioral treatment of pulsatile tinnitus and headache following traumatic head
injury. Objective polygraphic assessment of change.
AB - Pulsatile tinnitus is a disorder that can be extremely disabling. Nonetheless, it
has not been well-researched in the fields of psychology or behavioral therapy.
This article describes the evaluation and behavioral treatment of a gentleman
with pulsatile tinnitus. The evaluation included polygraphic assessment of
vasomotor and electromyographic function both before and after treatment. The
results show that the combination of lifestyle modifications and specific
behavioral interventions were successful in modifying not only self-report
indices of functioning, but also the underlying physiology related to the
disorder. The potential role of the various treatment components and the value of
including polygraphic assessment for informing treatment and evaluating outcome
are discussed.
PMID- 9755653
TI - Obsessive-compulsive disorder--Part I.
PMID- 9755655
TI - Diagnosis by computer.
PMID- 9755654
TI - The social usefulness of self-esteem: a skeptical view.
PMID- 9755656
TI - Experimental procedures and the placebo response.
PMID- 9755657
TI - Poorly controlled?
PMID- 9755658
TI - Gender, culture, and psychiatric symptoms.
PMID- 9755659
TI - Schizophrenic mother and child.
PMID- 9755660
TI - What is anxiety sensitivity?
PMID- 9755661
TI - Detection of high-risk human papillomavirus nucleic acid in archival cervical
smears.
AB - OBJECTIVE: To test the usefulness of a commercial DNA hybridization assay for the
detection of high-risk (HR) human papillomavirus (HPV) types in archival cervical
smears and to compare the sensitivity with that of polymerase chain reaction
(PCR) using consensus primers. STUDY DESIGN: Stained material was scraped from
archival slides and the pellet volume noted. DNA was extracted using
silica/guanidinium isothiocyanate and the quality checked by amplification of the
beta-globin gene. HR-HPV DNA was detected using a commercial hybrid capture assay
(HCA) and the results compared with an in-house amplification system with
consensus primers. RESULTS: Of 156 archival smears stored for 12-13 years, 20
were positive by HCA using an HR probe cocktail. Ninety-eight were also tested by
PCR, and 35 were positive. The percentage of HPV-positive samples increased with
the increasing size of the pellet. HR-HCA detected more positives in samples with
high grade squamous intraepithelial lesion (moderate/severe dyskaryosis).
CONCLUSION: Both hybridization by HCA and amplification by PCR could be used to
detect genital HPV in archival smears. The general primers PCR detected more
positives than HR-HCA but included HPV 6/11. While variation in sample size and
prolonged storage may reduce the quality of DNA, the use of archival material for
longitudinal studies of HPV presence is potentially worthwhile.
PMID- 9755662
TI - Radiation-induced acute immediate nuclear abnormalities in oral cancer cells:
serial cytologic evaluation.
AB - OBJECTIVE: To evaluate the dose-response relationship of nuclear abnormalities in
tumor cells collected by serial scrape smears from oral cancer patients on
fractionated radiotherapy. STUDY DESIGN: The study included 31 patients with
squamous cell carcinoma of the oral cavity treated by radiotherapy (60 Gy in 25
fractions; 2.4 Gy per fraction). Serial scrape smears were taken from each tumor
before treatment and after delivery of various fractions, usually 2 (4.8 Gy), 5
(12.0 Gy), 8 (19.2 Gy) or 12 (28.8 Gy). The smears were stained by Giemsa stain
and evaluated by light microscopy, and the number of micronucleated, binucleated,
nuclear budded and multinucleated cells were scored. Their relation to cumulative
dose was analyzed by Kruskal-Wallis one-way analysis of variance. The results
were expressed in terms of 1,000 mononucleated cells. RESULTS: Even before
treatment, most of the tumors showed various abnormally nucleated cells, and,
despite the high intertumoral variation (as indicated by the high variance), all
of them showed statistically significant dose-related increases. The mean values
before treatment and after irradiation with 28.8 Gy, respectively, were 2.8 and
19.5 (P < .0001) for micronucleated cells, 1.5 and 8.5 (P < .000001) for nuclear
budded cells, 8.2 and 35.5 (P < .0001) for binucleated cells, and 3.7 and 16.8 (P
< .0001) for multinucleated cells. When the different types of nuclear
abnormalities were combined and analyzed as "abnormally nucleated cells," the
mean count before treatment and after 28.8 Gy were 7.9 and 44.9 (P < .00001),
respectively. CONCLUSION: The study showed that radiation-induced
micronucleation, multinucleation, binucleation and nuclear budding in oral cancer
cells has statistically significant dose-related increases that become evident in
the initial few days of radiotherapy and that they can be differentiated well by
cytology. This dose-response relationship and the high intertumoral variations
suggest that serial assay of these changes has potential use for radiosensitivity
prediction.
PMID- 9755663
TI - Peritoneal washing cytology of ovarian tumors of low malignant potential:
correlation with surface ovarian involvement and peritoneal implants.
AB - OBJECTIVE: To correlate the cytologic diagnoses of peritoneal washings (PWs) with
histologic findings of ovarian tumors of low malignant potential (LMP). METHODS:
PW cytology from 90 patients with histologically confirmed ovarian tumors of LMP
were reviewed and correlated with histologic findings. RESULTS: In 90 LMP tumor
patients who underwent PW, cytologic diagnoses were reported as positive in 30
(33%) cases, atypical in 5 (6%) cases and negative in 55 (61%) cases. On review
of the five atypical cases, three were reclassified as negative and two as
positive. Peritoneal washings were positive in 20 (33%) of 60 patients with
serous LMP tumors, 12 (44%) of 27 patients with mucinous LMP tumors and none of 3
patients with mixed LMP tumors. The presence of positive cytology was highly
indicative of surface ovarian involvement or peritoneal implants in completely
staged or selectively biopsied patients (P < .0001). Of 60 (67%) patients who had
a staging laparotomy, positive PWs were seen in 3 (75%) of 4 cases with surface
involvement only, 13 (94%) of 14 cases with peritoneal implants only, 3 (100%) of
3 cases with both peritoneal implants and ovarian surface involvement, and 9
(23%) of 39 cases without evidence of surface involvement or peritoneal implants.
PWs were positive in 4 (13%) of 30 cases without staging laparotomy. CONCLUSION:
PW cytology is a sensitive indicator of peritoneal dissemination of ovarian
tumors of LMP. In addition, PWs will detect a high percentage of patients with
subclinical intraperitoneal extension of such tumors and should be used routinely
in the staging of ovarian tumors of LMP.
PMID- 9755664
TI - Electron microscopic examination of cytologic samples.
AB - OBJECTIVE: To review the results of observations of cytologic samples performed
in our laboratory by light microscopy (LM), scanning electron microscopy (SEM)
and transmission electron microscopy (TEM) performed in succession (LM-SEM-TEM
examination) using the same cytologic sample and to assess the diagnostic value
of this method of successive examination. STUDY DESIGN: Using a previously
reported method of LM-SEM-TEM sample preparation and observation, we analyzed 201
cytologic specimens over a seven-year period (1986-1993) and investigated whether
the histologic origin and malignancy can be estimated from SEM and TEM findings
on the cells. RESULTS: Observations of many cytologic samples over a seven-year
period (by LM, SEM and TEM) showed that several basic interpretations of cellular
ultrastructure are possible. In cases where cell identification was difficult by
LM, electron microscopic findings were sometimes useful for determining the
biologic characteristics of cells and for estimating their tissue origin.
Electron microscopic findings also provided important information for
cytodiagnosis. CONCLUSION: SEM and/or TEM findings are useful for determining the
morphologic (including biologic) characteristics of cells in cases where they
cannot be determined by LM. With the accumulation of data on electron microscopic
examination of cytologic samples, it is expected that in the future, electron
microscopy will continue to provide new information that can be used to improve
the accuracy of cytodiagnosis by LM.
PMID- 9755665
TI - Cytologic features of hemangioblastoma: comparison with meningioma, anaplastic
astrocytoma and renal cell carcinoma.
AB - OBJECTIVE: To compare the features of intraoperative smears of hemangioblastomas
with those of tumors with which it is most likely to be confused: meningiomas,
anaplastic astrocytomas and renal cell carcinomas. STUDY DESIGN: Examples of
hemangioblastomas with high-quality intraoperative smears were retrieved from the
files of University Hospital, University of Southern California and Los Angeles
County-University of Southern California. The characteristics of these smears
were compared to those of meningiomas, anaplastic astrocytomas and renal cell
carcinomas by two observes. RESULTS: Smears of hemangioblastomas were cellular
but remarkably cohesive. Cytoplasmic borders were indistinct. The nuclei were
hyperchromatic and mildly pleomorphic and had a relatively evenly dispersed
chromatin pattern. Hemosiderin was invariably present. Smears of meningiomas,
anaplastic astrocytomas and renal cell carcinomas were more discohesive than
those of hemangioblastomas. Smears of hemangioblastomas lacked the cytoplasmic
fibrillarity of those of astrocytic neoplasms and distinct cytoplasmic borders
seen in smears of renal cell carcinoma. The nuclear features of the four
neoplasms studied also differed. CONCLUSION: Smears of hemangioblastomas have
characteristic features that differ reliably from those of meningiomas,
anaplastic astrocytoma and renal cell carcinoma, neoplasms that commonly enter
the differential with hemangioblastoma. Thus, a cytologic smear preparation made
at the time of frozen section may be an invaluable aid in the intraoperative
diagnosis of hemangioblastoma.
PMID- 9755667
TI - Extramedullary hematopoietic effusions.
AB - OBJECTIVE: To investigate the frequency and diagnostic implications of
extramedullary hematopoietic effusions. STUDY DESIGN: Smears of the effusions
diagnosed cytologically as myeloid metaplasia or extramedullary hematopoiesis and
their clinical records were reviewed and compared with the histologic diagnoses.
RESULTS: There were 7 pleural and 1 peritoneal effusion from 5 patients out of
20,793 pericardial, peritoneal and pleural effusions studied during a period of
21 years. CONCLUSION: When compensatory responses can be ruled out, the diagnosis
of extramedullary hematopoietic effusion points toward replacement of the bone
marrow by a metastatic process. The first primary to consider in males is lung
carcinoma.
PMID- 9755666
TI - Malignant pleural effusions after resection of pulmonary adenocarcinoma.
AB - OBJECTIVE: To evaluate the clinicopathologic features of malignant pleural
effusions secondary to pulmonary adenocarcinoma in patients who have undergone
surgical resection of the primary tumor. STUDY DESIGN: Clinical, pathologic and
cytologic material from 19 patients who developed malignant pleural effusions
after resection of pulmonary adenocarcinoma was reviewed. RESULTS: Malignant
effusions developed only in patients with either lymph node or pleural
involvement by neoplasm. Time to development of the effusion after resection and
overall survival correlated with histologic findings. Malignant effusions in
patients who survived > 24 months were secondary to another primary tumor (either
breast or a new pulmonary carcinoma). Malignant effusions developed significantly
sooner after resection (mean 5.0 +/- 2.0 months, median 5) in patients with lymph
nodal metastases than in those with pleural involvement by neoplasm (mean 11.2 +/
2.5 months, median 12) (Student's t test P = .01, Mann-Whitney U test .04).
Nevertheless, survival after resection for patients with lymph node involvement
(mean 9.0 +/- 3.6 months, median 8) and those with pleural involvement (mean 12.3
+/- 2.5 months, median 12) was not significantly different. CONCLUSION: Malignant
effusions developing in patients more than two years following resection of a
pulmonary adenocarcinoma are likely to be secondary to another primary neoplasm.
Lymph node and pleural involvement at the time of resection are risk factors for
the development of a malignant effusion. Patients with lymph node involvement
develop malignant effusions sooner than those with pleural involvement, but the
overall survival is not significantly different.
PMID- 9755668
TI - Marginal vacuoles in thyroid aspirates.
AB - OBJECTIVES: To report on two cases of metastatic follicular carcinoma with
marginal vacuoles (MVs) and review smear results in 441 solitary nodular goiters
(SNGs) for this cytologic feature. STUDY DESIGN: The first case was a 55-year-old
male who presented with a huge mass in the left hip region; the second case was a
50-year-old male with a thyroid nodule and a large mass on the scalp. The age of
the 441 ultrasonographically diagnosed SNG cases ranged from 11 to 75 years. The
May-Grunwald-Giemsa-stained fine needle aspiration (FNA) smears of these cases
were reviewed by one of the authors (D.K.D.) for various cytomorphologic
features, including MVs. RESULTS: FNA smears from the mass in the hip in the
first case showed follicular cells with acinar formation and MVs, indicating
metastatic follicular thyroid carcinoma (FTC). These features were of help in
detecting the thyroid primary, which had previously gone undetected. Aspiration
smears from the thyroid nodule and the mass on the scalp in the second case
showed tumor cells of FTC with MVs and microfilariae. Review of 441 SNG cases
revealed MVs in 42.6% of hyperplastic nodules; that rate was significantly higher
(P < .001) than that of colloid goiter (5.2%) and neoplastic goiter (13.3%) but
lower (P < .05) than that of thyrotoxic goiter (100%). MVs were limited to
neoplasms with a follicular component; that included 15% of follicular neoplasms
and 50% of follicular variant of papillary carcinoma (FVPC). The difference
between FVPC and the rest of the neoplastic goiters (6%) was statistically
significant (P = .002).
PMID- 9755669
TI - Bar-shaped nuclear chromatin in conjunctival samples: with cytologic features and
ultrastructural correlation.
AB - OBJECTIVE: To study the cytomorphologic features of bar-shaped chromatin in
conjunctival samples and assess whether there are morphologic similarities
between nuclear grooves seen in thyroid papillary carcinoma and bar-shaped
chromatin. STUDY DESIGN: A total of 10 conjunctival samples from five volunteers
were studied cytologically. Of the 10 samples, 2 showed barshaped chromatin. This
chromatin was studied using a light microscope, scanning electron microscope
(SEM) and transmission electron microscope (TEM). RESULTS: On SEM, bar-shaped
chromatin was observed as a fissure or shallow cracks. On TEM the barshaped
chromatin existed both in the center of the nuclei and in the nuclear membrane
and cytoplasm. It was surrounded by outer and inner membranes. CONCLUSION: It
seems that bar-shaped chromatin is formed by the nuclear membrane and that these
changes are essentially the same configuration as cytoplasmic invaginations
commonly present in papillary carcinoma of the thyroid.
PMID- 9755670
TI - Rescreen effect in conventional and PAPNET screening: observed in a study using
material enriched with positive smears.
AB - OBJECTIVE: To study the rescreen and PAPNET effects on enriched material derived
from smears screened routinely using PAPNET and conventional microscopy. STUDY
DESIGN: A series of 432 smears (containing 122 atypical squamous cells of
undetermined significance [ASCUS] plus 44 at least dysplastic squamous
intraepithelial lesion-positive [SIL+] ones), screened routinely with the
conventional method, were rescreened using the PAPNET system. Another series of
461 smears (containing 140 ASCUS + 52 SIL+ ones) screened routinely with PAPNET
were rescreened conventionally. The rescreen effect, defined as the effect of
differences between the rescreen and routine screening situation, was
investigated by comparing the rescreen results in both series of smears with the
routine results in both series. The effect of using either method of screening
was studied by comparing the PAPNET results in both series with the results of
conventional screening in both series. RESULTS: The rescreen effect was
statistically significant both for a higher number of smears classified as
negative (less than ASCUS) and a higher number of smears classified as high grade
SIL or more. PAPNET-assisted screening resulted in a significantly higher number
of smears classified as high grade SIL+, although for this latter finding there
is an unexplained significant difference between conventional and PAPNET-screened
cases in the changes made by the cytopathologist in the cytotechnologists'
diagnoses. CONCLUSION: The rescreen effect should not be ignored when enriched
material is used.
PMID- 9755671
TI - The immediate postconization endocervical smear: evaluation of its utility in the
detection of residual dysplasia.
AB - OBJECTIVE: To determine the diagnostic value of obtaining an endocervical smear
for cytologic examination immediately following cervical conization (by either
the loop electrosurgical excision procedure or large loop excision of the
transformation zone) in the detection of residual squamous dysplasia. STUDY
DESIGN: Thirty-eight cases were identified in which cervical conization was
immediately followed by endocervical sampling (most commonly using a brush) and
smear. RESULTS: Twenty-one of the 38 postconization endocervical smears (55%)
were either unsatisfactory or sub-optimal for evaluation due to cellular
distortion (i.e., cautery artifact), degeneration or obscuring blood. Histologic
in evaluation showed negative endocervical margins in 32 cases (84%) and positive
endocervical margins in 6 cases (16%), including both low and high grade squamous
intraepithelial lesions. The endocervical smears in the 32 cases with a negative
surgical margin did not demonstrate evidence of dysplasia. However, in the six
cases with histologically positive margins, postconization endocervical smears
also failed to identify any evidence of dysplasia. CONCLUSION: Immediate
postconization endocervical smears do not appear to be useful for the detection
of residual disease in patients undergoing conization for squamous dysplasia of
the cervix.
PMID- 9755672
TI - Cell block preparation of a Burkitt's lymphoma cell line as a positive control
for in situ hybridization for Epstein-Barr virus.
AB - OBJECTIVE: To examine the feasibility of the use of a cell block preparation of
Epstein-Barr virus (EBV)-infected Burkitt's lymphoma cell line (EB-3) as a
positive control for in situ hybridization (ISH) for EBV-encoded RNA (EBER).
STUDY DESIGN: EB-3 cells were processed into cell block and cytocentrifuge
preparations. ISH for EBER was performed, and the results were compared with a
commercially available EBV positive control slide (cytocentrifuge). RESULTS: The
cost of preparing the cell block and cytocentrifuge sample was only a fraction of
the price of commercial control slides. ISH for EBER was strongly stained in all
preparations with similar intensity of staining but with a much higher number of
positive cells in the cell block. Although the cellular details in the cell block
were considerably inferior to those on the cytocentrifuge and commercial control
slide, with distortion of nuclei and smudging of chromatin, the interpretation of
the ISH results was unaffected. The cell block was stable at room temperature
when examined after one year. CONCLUSION: The cell block preparation of an EBV
infected Burkitt's lymphoma cell line serves as a reliable, stable and a
relatively inexpensive control, with good preservation of cellular details of
cellular RNA for ISH study for EBER in the detection of latent infection with
EBV.
PMID- 9755673
TI - Squash preparation and frozen section in intraoperative diagnosis of central
nervous system tumors.
AB - OBJECTIVE: To investigate the diagnostic accuracy of squash preparation (smears)
and frozen section (FS) in the rapid intraoperative diagnosis of central nervous
system (CNS) tumors. STUDY DESIGN: One hundred eighty-three CNS tumors were
examined over a period of 18 months (January 1995-June 1996). All these were open
biopsies, and the smear interpretation was compared with FS findings and paraffin
section diagnosis. RESULTS: In 183 tumors, squash preparation was satisfactory in
156 cases (85.2%), and the diagnostic accuracy was 89.7% (140/156). The accuracy
of FS diagnosis was 90.4% (141/156). CONCLUSION: The squash smear preparation is
a fairly accurate and reliable tool in the rapid intraoperative diagnosis of CNS
tumors. The accuracy of this technique is nearly as good as that of FS (P value =
.9877). With the advent of stereotactic biopsies, the pathologist may have to
depend entirely upon cytologic features for a definitive diagnosis.
PMID- 9755674
TI - Fine needle aspiration cytology of malignant chondroid syringoma: a case report.
AB - BACKGROUND: Chondroid syringoma, a tumor of the eccrine glands, was previously
called mixed tumor of skin as it has both mesenchymal and epithelial elements.
Malignancy in this tumor is extremely rare. Although there are a few reports
describing the cytomorphologic features of chondroid syringoma, the cytologic
findings of its malignant counterpart have not been described. CASE: A 40-year
old female presented with a recurrent swelling on the scalp of one year's
duration. Fine needle aspiration yielded blood-mixed gelatinous material. May
Grunwald-Giemsastained smears showed epithelial cells arranged in cordlike
structures and ill-formed glands against a myxomatous background. The epithelial
cells had scanty cytoplasm and markedly pleomorphic nuclei with prominent
nucleoli. A few cells in the stroma had a halo around them and a resemblance to
cartilage cells. A preoperative diagnosis of malignant chondroid syringoma was
made. The tumor was excised, and the cytologic diagnosis was confirmed on
histopathology. CONCLUSION: Cytomorphologic features of a rare case of malignant
chondroid syringoma are reported for the first time. The presence of malignant
epithelial cells against a myxoid background with a few chondroid foci helped in
making a correct preoperative diagnosis.
PMID- 9755675
TI - Fine needle aspiration cytology of gastric solitary fibrous tumor: a case report.
AB - BACKGROUND: Solitary fibrous tumors (SFT) occur mainly in the pleura and other
serosal sites. However, they have been found in extraserosal sites and should be
considered in the differential diagnosis (DDx) of any spindle cell lesion,
including those in the gastrointestinal tract. In this report, we describe fine
needle aspiration (FNA) cytologic evaluation of a gastric SFT, emphasizing the
role of immunocytochemistry in the DDx. CASE: Computerized tomography-guided FNA
of a subserosal gastric mass in a 77-year-old female was performed. The
moderately cellular smears showed neoplastic cells arranged in interlacing
fascicles and in a "patternless" pattern. There was variable collagenous stroma.
The cell block revealed a similar pattern, with a single mitotic figure. Nuclear
atypia and necrosis were absent. The neoplastic cells were strongly reactive for
vimentin and CD34, with weak focal reactivity for smooth muscle actin, suggestive
of vessels in tangential section. They were nonreactive for muscle specific
actin, desmin, S-100 and pancytokeratin. Other immunocytochemical markers were
also studied. CONCLUSION: SFT should be considered in the DDx of spindle cell
lesion of the stomach. Cell block and immunocytochemical markers, especially
CD34, were extremely useful in the diagnosis of SFT on FNA.
PMID- 9755676
TI - Aspiration cytology of ectopic cervical thymoma mimicking a thyroid mass. A case
report.
AB - BACKGROUND: Ectopic cervical thymoma, first described in 1941 by Boman, is an
uncommon tumor of the neck displaying the same histologic features as mediastinal
thymoma. Since it is commonly located in the anterolateral part of the neck or is
subjacent to or inside the lower pole of the thyroid, the mass is often confused
as being of thyroid origin. CASE: A 68-year-old female presented with dyspnea and
an anterior neck mass found on routine chest roentgenography. The thyroid scan
showed a cold nodule in the lower pole of the left part of the thyroid. Fine
needle aspiration (FNA) cytology revealed large numbers of small lymphocytes with
hyperchromatic nuclei and frequent clumping pattern in the pale, eosinophilic,
fluid background. A few clusters of epithelial cells without atypism were
interpreted as thyroid follicular cells. The overall cytologic features were
misinterpreted as malignant lymphoma of the thyroid. However, the histologic
diagnosis was thymoma, predominantly cortical type. CONCLUSION: The ectopic
cervical thymoma is sometimes misdiagnosed as Hashimoto's thyroiditis, anaplastic
carcinoma and malignant lymphoma of thyroid on FNA cytology or frozen diagnosis
due to its rarity. Therefore, the differential diagnosis of a neck mass showing a
variable composition of lymphocyte and epithelial component in a pale,
eosinophilic, fluid background should also include ectopic cervical thymoma,
especially in elderly females.
PMID- 9755677
TI - Fine needle aspiration cytology of fibrous dysplasia: a case report.
AB - BACKGROUND: Fibrous dysplasia (FD) is a benign disorder of bone consisting of
intramedullary proliferation of fibrous tissue and irregularly distributed,
poorly developed bone. Although tumorlike in appearance, FD is probably a
condition resulting from failure of maturation from woven to lamellar bone. The
histology of FD has been well characterized since Lichtenstein first reported it,
in 1938; however, the cytologic appearance has been described only rarely. To our
knowledge, this is the first case report of fine needle aspiration (FNA)
cytomorphology of FD. CASE: A 30-year-old female with breast carcinoma, diagnosed
a month earlier, underwent computed tomography-guided FNA of a rib lesion
radiologically thought to represent FD, although metastatic cancer could not be
excluded. The smears contained blood, occasional osteoclastic multinucleated
giant cells and frequent C-shaped fibrillary structures with dark central areas
and lighter peripheries, representing woven bone. The cytologic/radiologic
impression of FD was confirmed histologically. CONCLUSION: FNA cytodiagnosis of
FD is possible in the setting of consistent clinical and radiologic findings.
PMID- 9755678
TI - Cytodiagnosis of malignant melanoma of soft tissue: report of a case with
diagnosis by intraoperative cytology.
AB - BACKGROUND: Malignant melanoma of soft tissue (MMST) is a rare tumor and consists
of < 1% of all soft tissue neoplasms. There are few reports on its cytodiagnosis.
CASE: A 14-year-old male attended the Department of Orthopedics, Juntendo
University Urayasu Hospital, in August 1994 because of a painless tumor in the
distal portion of the left thigh. Intraoperative imprint smear examination led to
a diagnosis of malignant melanoma, and wide resection of the tumor, including the
surrounding normal tissue, was performed. On cytologic examination, the
background was relatively clean, with tumor cells distributing individually or in
clusters. Under high magnification, the tumor cells were seen to contain a
slightly enlarged, conspicuous nucleolus and large cell body. The cells varied in
shape from polygonal to spindle shaped, with a few multinuclear giant cells.
Melanin and glycogen were observed in varying degrees in the tumor cells.
CONCLUSION: MMST can be diagnosed easily if melanin is observed in the cytoplasm.
Even in the absence of melanin, the tumor has relatively characteristic
cytomorphology. Intraoperative cytology is useful for an accurate diagnosis of
the tumor.
PMID- 9755679
TI - Sclerosing lipogranuloma of the scrotum: report of a case with fine needle
aspiration biopsy findings.
AB - BACKGROUND: Sclerosing lipogranuloma of the scrotum is a rare granulomatous
lesion of the subcutis. To the best of our knowledge, there have been no English
language reports dealing with its cytologic findings. CASE: A fine needle
aspiration specimen from a mass in the scrotum in a 62-year-old male showed
epithelioid cells, multinucleated giant cells and fibroblasts, which were
suggestive of sclerosing lipogranuloma. The diagnosis was confirmed by histology
of the resected specimen. CONCLUSION: Fine needle aspiration cytology is useful
for the diagnosis of sclerosing lipogranuloma. It is important, however, to
interpret the fine needle aspiration cytology specimen in conjunction with the
clinical information.
PMID- 9755680
TI - Macrofollicular variant of papillary thyroid carcinoma diagnosed by fine needle
aspiration biopsy: a case report.
AB - BACKGROUND: Macrofollicular variant of papillary thyroid carcinoma (PTC) is an
uncommon, recently described thyroid tumor. By frozen section it can be confused
easily with goiter or macrofollicular adenoma. CASE: A 41-year-old female
presented with a huge mass in the right thyroid lobe, cold on scintigraphy. By
fine needle aspiration fluid was obtained. Smears of the sediment of the fluid
showed epithelial cells with morphologic features diagnostic of PTC. Frozen
section diagnosis was benign. CONCLUSION: This is the first reported case of
macrofollicular variant of PTC diagnosed preoperatively by cytology. In our case
the cytology was similar to that of cystic PTC.
PMID- 9755681
TI - Gastrointestinal autonomic nerve tumor (plexosarcoma): report of a case with fine
needle aspiration biopsy and histologic, immunocytochemical and ultrastructural
study.
AB - BACKGROUND: Gastrointestinal stromal tumors (GISTs) encompass a large group of
mesenchymal neoplasms that display common cytologic spindle-shaped morphology on
light microscopy. Immunocytochemical and ultrastructural studies can demonstrate
several patterns of differentiation. CASE: A 70-year-old male presented with two
intraabdominal small bowel masses. The cytopathologic features of a fine needle
aspiration biopsy (FNAB) included plump spindle cells in densely populated
aggregates or in a fasciculated pattern, without significant pleomorphism. An
epithelioid component in a lobular arrangement with abundant, eosinophilic
cytoplasm was also noted. The nuclei were vesicular, with a very evident,
eosinophilic nucleolus and finely distributed chromatin. Groups of loosely
cohesive cells with slender, dendritic-like cytoplasm were evident.
Immunocytochemical study of the embedded, fine needle aspirated fragments of the
neoplasm demonstrated immunoreactivity for vimentin and neuron-specific enolase.
Cytokeratin immunoreactivity or muscular, vascular, neuroendocrine or nerve
sheath differentiation failed to be demonstrated. The cytologic and
immunocytochemical findings correlated well with the histologic features of the
neoplasm. The morphologic diagnosis was confirmed by ultrastructural study.
CONCLUSION: FNAB and immunocytochemistry can be valuable in making the correct
diagnosis between gastrointestinal stromal tumors.
PMID- 9755682
TI - Recurrent secondary hyperparathyroidism after autotransplantation into the
sternocleidomastoid muscle: report of a case with fine needle aspiration
findings.
AB - BACKGROUND: Recurrent hyperparathyroidism may occur following parathyroid
autotransplantation due to autogenous function of the muscle-engrafted tissue.
Parathyroid lesions are uncommonly diagnosed on cytology. CASE: A 31-year-old
female with chronic renal failure presented with an elevated parathyroid hormone
level and a neck mass in the left sternocleidomastoid muscle, the site of a
previous parathyroid autograft. Fine needle aspiration of the mass revealed high
cellularity, with perivascularly arranged, three-dimensional, branching clusters;
individual cells; and naked nuclei exhibiting anisonucleosis. A diagnosis of
parathyroid graft hyperplasia was made by fine needle aspiration and subsequently
by histopathologic examination. CONCLUSION: Fine needle aspiration is an
effective tool for confirming the presence of parathyroid autograft hyperplasia,
thus allowing the correct surgical approach.
PMID- 9755683
TI - Primary small cell anaplastic carcinoma of the breast diagnosed by fine needle
aspiration cytology: a case report.
AB - BACKGROUND: Small cell anaplastic carcinoma most commonly presents as a lesion in
the central portion of the lung but occasionally is found in peripheral
locations. Only seven cases originating in the breast have been described. To our
knowledge, the preoperative diagnosis of this entity by fine needle aspiration
has not been previously reported in the cytologic literature. CASE: A 67-year-old
female presented with a 4 x 3-cm, rapidly growing mass in the left breast. On
fine needle aspiration (FNA) the tumor was soft to the needle and yielded a
highly cellular aspirate. CONCLUSION: In this case the morphologic interpretation
of FNA, combined with the immunocytochemical demonstration of neuron-specific
enolase in tumor cells, was extremely helpful in establishing the nature of the
breast tumor.
PMID- 9755684
TI - AgNOR evaluation in pulmonary aspiration cytology.
PMID- 9755685
TI - Current state of malpractice litigation.
PMID- 9755686
TI - Breast metastases.
PMID- 9755687
TI - Plant cells mimicking adenocarcinoma in sputum.
PMID- 9755689
TI - Echinococcus oligarthrus.
PMID- 9755688
TI - Infarction of a thyroid nodule after fine needle aspiration biopsy.
PMID- 9755690
TI - Necrosis and Charcot-Leyden crystals.
PMID- 9755691
TI - A proposed methodology for evaluating secondary screening (rescreening)
instruments for gynecologic cytology: Intersociety Working Group for Cytology
Technologies.
PMID- 9755692
TI - Diffusion-weighted MR imaging of acute cerebral ischemia.
AB - Diffusion-weighted MR imaging has been used in studies on experimental animal
models and on patients with acute cerebral ischemia. Compared with CT and
conventional MR techniques, diffusion-weighted imaging can provide earlier and
more precise detection of the location and the extent of an ischemic lesion
during the critical first few hours after the onset of stroke. Quantitative
apparent diffusion coefficient (ADC) mapping of the brain water can also be
carried out by recording a series of diffusion-weighted images with different
amplitudes of the displacement encoding gradients. ADC maps can provide important
information about the extra- and intracellular water homeostasis. ADC reduction
of the tissue water is one of the early signals of the pathophysiological cascade
resulting from ischemic tissue injury. Diffusion MR imaging has become a valuable
tool in stroke research. It may also prove a valuable tool in monitoring the
efficiency of therapeutic effects in stroke patients. It is our intention to
provide an overview of the recent development in this area with emphasis on the
diffusion-weighted MR techniques, and to discuss the possible underlying
biophysical mechanisms responsible for the contrast of diffusion-weighted
imaging.
PMID- 9755693
TI - The effect of paramagnetic contrast media on T1 relaxation times in brain tumors.
AB - PURPOSE: To study T1 relaxation times in brain tumors before and after
paramagnetic contrast medium injection. MATERIAL AND METHODS: Seventeen patients
with a known or suspected brain tumor were studied with an echo planar inversion
recovery imaging sequence using 10 different inversion times. Double injections
of Gd chelate (0.1 mmol/kg + 0.2 mmol/kg) were administered in 5 patients, and a
single 0.2-mmol/kg dose in 12 patients. RESULTS: After the 0.2-mmol/kg dose, T1
decreased from 1121 +/- 130 ms to 987 +/- 103 ms in gray matter (p < 0.001), and
from 666 +/- 29 ms to 646 +/- 27 ms in white matter (p < 0.001). Tumor T1
shortened from 1515 +/- 319 ms to 717 +/- 383 ms. After the 0.1-mmol/kg dose (n =
5), tumor T1 decreased from 1116 +/- 261 ms to 793 +/- 202 ms and after the
additional 0.2-mmol/kg dose it decreased further to 526 +/- 141 ms. CONCLUSION:
Postcontrast T1 relaxation times in tumors showed considerable variation and
remained, on average, relatively long compared to white matter. This should be
taken into account when deciding which pulse sequences, imaging parameters, and
contrast agent doses are optimal for brain tumor imaging.
PMID- 9755694
TI - White matter abnormalities in tuberous sclerosis complex.
AB - PURPOSE: The aim of this study was to investigate and describe the range of white
matter abnormalities in children with tuberous sclerosis complex by means of MR
imaging. MATERIAL AND METHODS: A retrospective cross-sectional study was
performed on the basis of MR imaging findings in 20 cases of tuberous sclerosis
complex in children aged 17 years or younger. RESULTS: White matter abnormalities
were present in 19/20 (95%) cases of tuberous sclerosis complex. These were most
frequently (19/20 cases) found in relation to cortical tubers in the
supratentorial compartment. White matter abnormalities related to tubers were
found in the cerebellum in 3/20 (15%) cases. White matter abnormalities described
as radial migration lines were found in relation to 5 tubers in 3 (15%) children.
In 4/20 (20%) cases, white matter abnormalities were found that were not related
to cortical tubers. These areas had the appearance of white matter cysts in 3
cases and infarction in the fourth. In the latter case there was a definable
event in the clinical history, supporting the diagnosis of stroke. CONCLUSION: A
range of white matter abnormalities were found by MR imaging in tuberous
sclerosis complex, the commonest being gliosis and hypomyelination related to
cortical tubers. Radial migration lines were seen infrequently in relation to
cortical tubers and these are thought to represent heterotopic glia and neurons
along the expected path of cortical migration.
PMID- 9755695
TI - An experimental high-resolution MR coil for the imaging of pathological findings
in the post mortem brain stem.
AB - PURPOSE: The purpose of this study was to evaluate the potential of an
experimental coil using a whole-body MR unit to delineate pathological changes
within formalin-fixed human brain stems. MATERIAL, METHODS, AND RESULTS: The MR
images of 9 brain stems were compared with gross anatomy and corresponding
histological sections. The resolution of the images was high enough to depict
areas of clinically relevant pathological alterations.
PMID- 9755696
TI - MR findings in three pituitary abscesses. Case reports.
AB - We present MR findings in 3 surgically proved cases of pituitary abscess. All
lesions were seen as a sellar cystic mass with a thin rim of enhancement. In
addition, the pituitary stalk was thickened in 2 cases in which central diabetes
insipidus developed. These findings may be suggestive of pituitary abscess.
PMID- 9755697
TI - Mechanism of contrast enhancement in breast lesions at MR imaging.
AB - PURPOSE: The aim of the study was to explain why breast lesions are enhanced by
contrast medium at MR imaging and to elucidate the histopathological basis for
the overlap in the enhancement patterns of benign and malignant breast lesions.
MATERIAL AND METHODS: Ten invasive breast carcinomas and 10 benign breast lesions
were selected for the study. Of the 10 carcinomas, 5 showed a strong and early
contrast enhancement, and 5 did not. Of the 10 benign lesions, 5 showed a strong
and early contrast enhancement, and 5 showed no enhancement. The following
morphometric variables were evaluated: proliferation cell index of neoplastic
parenchymal cells, S-phase fraction, nuclear ploidy analysed by image DNA
cytometry, microvessel density, and the percentage proportion of the interstitial
area. RESULTS: Contrast enhancement was related to the proliferating activity of
the hyperplastic or neoplastic parenchymal cells and was inversely correlated
with the interstitial area in carcinomas as well as in benign tumours and non
neoplastic lesions of the breast. CONCLUSION: Morphometric variables play an
important role in the general mechanism of MR contrast enhancement in
examinations of the breast and explain the histopathological basis for the
overlap in the enhancement patterns of benign and malignant breast lesions.
PMID- 9755698
TI - Detectability of simulated masses and calcifications in mammography. Development
of a phantom and a new method for determination of receiver operating
characteristics.
AB - PURPOSE: To develop a method for receiver operating characteristics (ROC) studies
in mammography. MATERIAL AND METHODS: We developed a phantom based on excised
breast tissue and overlay tiles that could be arranged in an arbitrary pattern
across the surface of the breast tissue. Some of the tiles contained structures
simulating calcifications or masses that produced image contrast near the
experimentally determined detection threshold. Based on this phantom, a
methodology for performing ROC studies in mammography was developed. The ROC
curves were constructed from reporting schemes filled in by radiologists at five
different laboratories. The curves were determined by a novel method: a non
linear least-squares fit of a mathematical model to the data. RESULTS: There were
large differences among the areas under the ROC curves obtained from the five
laboratories.
PMID- 9755699
TI - Assessment of image quality and total performance in Norwegian mammography
laboratories. Findings in a national survey based on different phantoms and ROC
methodology.
AB - PURPOSE: To assess the image quality at different mammography laboratories.
MATERIAL AND METHODS: Two commercial mammographic test phantoms and one phantom
based on excised mammary tissue were used in an assessment of the imaging chain
and total performance at 45 Norwegian mammography laboratories. The breast-tissue
phantom was used for a receiver operating characteristics (ROC) analysis. This
was carried out by putting overlays with identifiable regions (some of which
contained a cluster of simulated calcifications) on top of the mammary tissue,
and then having a radiologist report the confidence of a finding for each region.
RESULTS AND CONCLUSION: The areas under the ROC curves were in general high. In
nearly all the laboratories, performance was improved when a magnification
technique was applied. There were wide variations among the laboratories in total
performance as measured by the area under the ROC curve, and also in the physical
parameters derived by means of the commercial phantoms. In general, a good ROC
performance was associated with a good physical performance in the imaging chain.
PMID- 9755700
TI - Dose reduction in thorax radiography in simulated neonates with additional
filtration and digital luminescence radiography.
AB - PURPOSE: To determine the minimum acceptable radiation dose for an adequate image
quality in thorax a.p. radiographs of neonates using mobile X-ray equipment.
MATERIAL AND METHODS: The influence of additional filtration (1.0 mm Al + 0.1 mm
Cu) on image quality and radiation dose was determined for the speed class 400
screen-film system (SFS) and digital luminescence radiography (DLR) by making
radiographs of a test phantom. Conventional and digital thorax a.p. radiographs
of a rabbit were produced using various tube current-time products. The quality
of the rabbit radiographs was judged by eight radiologists applying image quality
criteria according to the German guidelines and the recommendations of the
European Community. RESULTS: The added filter resulted in a dose reduction of 39%
at 66 kV. DLR gave a further dose reduction of 25% in comparison to the speed
class 400 SFS while maintaining adequate image quality, i.e. the radiographs were
clinically acceptable with regard to quality criteria. CONCLUSION: The radiation
dose resulting from thorax a.p. radiographs of neonates can be reduced by
approximately 50% with the use of additional filtration and DLR.
PMID- 9755701
TI - Pleural pneumatocoeles mimicking congenital cystic adenomatoid malformation of
the lung. A case report.
AB - We present the plain radiographic and CT appearances of large intrapleural
pneumatocoeles in a 13-week-old infant, resulting in compression atelectasis of
the left upper and lower lobes, and mimicking congenital cystic adenomatoid
malformation.
PMID- 9755702
TI - Clinical value of imaging techniques in childhood osteomyelitis.
AB - PURPOSE: The traditional approach to investigating suspected osteomyelitis in
children includes conventional radiography and bone scintigraphy. The roles of
US, CT and MR imaging are controversial. Our objective was to determine whether
the additional use of these modalities would yield information likely to lead to
treatment modification. MATERIAL AND METHODS: Sixty-five children with clinically
suspected osteomyelitis took part in a prospective study. All patients underwent
conventional radiography and bone scintigraphy. In addition to this, US, CT and
MR imaging were all performed in 33 patients; the remaining 32 patients were
examined with various combinations of these three modalities. The value of the
additional information obtained was estimated retrospectively by a pediatric
orthopedic surgeon in terms of possible modification of treatment. RESULTS: MR
imaging was the modality with the highest sensitivity and specificity for
detecting osteomyelitis. MR yielded information likely to influence treatment in
the greatest proportion of patients (45%) followed by US (30%). CONCLUSION: The
standard investigation protocol with the addition of US (because of its ability
to detect subperiosteal abscesses early and simply) is adequate in uncomplicated
cases. When additional imaging is required to outline a lesion, or in complicated
cases, and when bone scintigraphy is inconclusive, MR imaging should also be
performed. CT should be considered when MR investigation is not available or when
anesthesia is required but cannot be provided.
PMID- 9755703
TI - Synovitis in Legg-Calve-Perthes disease. Evaluation with MR imaging in 84 hips.
AB - PURPOSE: To evaluate, by means of MR imaging, the degree and persistence of
synovitis in the hip joint in Legg-Calve-Perthes disease and to correlate the
degree of synovitis with the degree of epiphyseal necrosis. MATERIAL AND METHODS:
A total of 170 MR images in 72 patients (84 hips) were examined. The T2-weighted
MR images were taken in the coronal plane in order to evaluate the degree of
synovitis in the hip joint. RESULTS: MR revealed synovitis in all cases in the
early phase of the disease. In Catterall group II, synovitis was discreet to
moderate for up to 6 months after diagnosis. Hips with more severe necrosis,
Catterall groups III and IV, had moderate or intense degrees of synovitis. There
was a correlation between the degree of synovitis and the lateral pillar
classification according to HERRING et al. Also, there was a good correlation
between the extent of signal changes in the epiphysis on MR imaging and the
degree of synovitis. There was no difference when signal changes were evaluated
on T1- or T2-weighted images. Signs of synovitis could be seen for up to 30
months after diagnosis in Catterall group I hips, and in Catterall groups II and
III for up to 36 months, and in 2 cases even longer. Some Catterall group IV hips
had discreet or mild synovitis for 60 months or more, after diagnosis.
CONCLUSION: The degree of synovitis on MR imaging correlates to the extent of
epiphyseal necrosis seen on radiographs or MR imaging as well as to the lateral
pillar classification, i.e. to a poor clinical outcome. In Catterall group IV
hips, synovitis can even persist for up to 60 months after diagnosis.
PMID- 9755704
TI - Bone mineral density and spongiosa architecture in correlation to vertebral body
insufficiency fractures.
AB - OBJECTIVE: The clinical value of spinal quantitative CT (sQCT) and the structural
patterns of the vertebral bone were studied. MATERIAL AND METHODS: sQCT was
performed on 246 patients with a mean age of 57 years for whom conventional
lateral radiographies of the thoracic and lumbar spine were available. All
patients were suffering from back pain of unknown etiology. The bone mineral
density (BMD) of the midvertebral section of 3 lumbar vertebral bodies was
determined by means of single-energy-(SE)-weighted QCT (85 kV). Spongiosa
architecture and density profile analyses were made in the axial images. This was
contrasted to BMD values ascertained in SE QCT. The mean BMD was compared to the
number of fractures and the patients were divided into three groups: group I--no
fracture; group II--one fracture; and group III > 1 fracture. RESULTS: The mean
BMD was: 134.3 (74.1-187.5) mg hydroxyapatite (HA)/ml in group I; 79.6 (58.6
114.3) mg HA/ml in group II; and 52.4 (13.1-79.1) mg HA/ml in group III. A
significant deterioration in spongiosa structure was found with increasing
demineralization: strongly rarefied patterns predominated in the fracture groups
II and III. CONCLUSION: sQCT provides a good risk assessment of the occurrence of
vertebral body insufficiency fractures.
PMID- 9755705
TI - Functional MR imaging of the cervical spine in patients with rheumatoid
arthritis.
AB - PURPOSE: To evaluate functional MR imaging in patients with rheumatoid arthritis
(RA) involving the cervical spine. MATERIAL AND METHODS: We used a device that
allows MR examination to be made of the cervical spine in infinitely variable
degrees of flexion and extension. Dynamic functional MR imaging was performed on
25 patients with RA. RESULTS: Functional MR imaging was able to show the degree
of vertebral instability of the occipito-atlantal or atlanto-axial level as well
as the subaxial level. By performing functional MR imaging, we were able to
demonstrate the extent of synovial tissue around the dens, and the impingement
and displacement of the spinal cord during flexion and extension. The basilar
impression, the cord impingement into the foramen magnum, the cord compression,
the slipping of vertebrae, and the angulation of the cord were all much more
evident in functional than in static MR imaging. CONCLUSION: Functional MR
imaging provided additional information in patients with RA, and is valuable in
patients who have a normal MR study in the neutral position and yet have signs of
a neurological deficit. Functional MR imaging is important in the planning of
stabilizing operations of the cervical spine.
PMID- 9755706
TI - High-resolution MR imaging of the cutis and subcutis. Histological correlation.
AB - OBJECTIVE: To determine whether the spatial resolution that can be achieved with
currently available MR devices is adequate for the evaluation of skin disease.
MATERIAL AND METHODS: We correlated high-resolution MR images of the skin with
dermatohistopathology in 26 patients. The examinations were carried out on a 1.0
T imager using a commercially available surface coil (ID 7.5 cm) and optimized SE
and GE sequences. Image quality was assessed by four readers on a questionnaire.
RESULTS: The visualization of the dermis, subcutaneous tissue, and muscle fascia
allowed a pattern analysis that gave findings identical to those at
dermatohistopathology. It was possible to distinguish septal from lobular
panniculitis, and lipatrophia from sclerodermia. Images with contrast media
infusion were useful in the differential diagnosis. CONCLUSION: High-resolution
MR imaging may narrow down the differential diagnosis of various skin diseases
and may help to reduce the number of skin biopsies on certain indications.
PMID- 9755707
TI - MR appearance of anomalous insertion of the medial meniscus. A case report.
AB - We report on the MR imaging of an anomalous medial meniscus with a tear in a 41
year-old man. Anomaly of the medial meniscus is rare and difficult to diagnose
clinically. The MR images contributed to the pre-arthroscopic diagnosis and
arthroscopy confirmed the lesion. The anomalous meniscus was not related to the
symptoms.
PMID- 9755708
TI - MR and CT cholangiography in evaluation of the biliary tract.
AB - OBJECTIVE: To compare MR and CT cholangiography (MRC and CTC) in evaluating the
anatomy of the extrahepatic biliary tract and the pathology related to the
gallbladder. MATERIAL AND METHODS: Twenty-three patients underwent MRC and CTC
with a biliary contrast medium for investigation of biliary disease. 3D displays
of both were also obtained. Endoscopic retrograde cholangiography was performed
in 17 patients, and the pathology of all 23 was evaluated. RESULTS: Overall, the
image quality was higher with CTC than with MRC (4.7 vs 3.9, p < 0.05). The
cystic duct was demonstrated better by CTC than MRC (p < 0.05). Multiplanar
reformation (MPR) and source images provided additional information to that
obtained from 3D MRC and CTC images. Gallstones were revealed in 6 patients by
CTC and in 5 of these 6 by MRC. In 2 patients with cholecystitis, CTC
demonstrated gallbladder wall thickening but MRC did not. In 3 patients with
adenomyomatosis. MRC demonstrated Rokitansky-Aschoff sinuses (RAS) while CTC
demonstrated focal gallbladder wall thickening in all 3 and RAS in 1 of them.
CONCLUSION: Both MRC and CTC provided anatomical and pathological information
about the biliary system. With both techniques, however, either MPR or source
images proved necessary in addition for evaluating the biliary system anatomy and
pathology. The gallbladder wall was depicted clearly in source CTC, but MRC is
recommended for the evaluation of adenomyomatosis because it depicts RAS clearly.
PMID- 9755709
TI - Colour Doppler imaging of shunts from the left portal branch in portal
hypertension. Description of a typical pattern.
AB - PURPOSE: To describe the typical colour Doppler appearance of a shunt through the
parenchyma of the left lobe of the liver in portal hypertension. MATERIAL AND
METHODS: Ultrasound images of 141 patients with biopsy-verified cirrhosis were
reviewed. Special note was taken of the appearance of shunts from the left portal
branch. RESULTS: In 28 patients, shunts from the left portal branch were detected
ultrasonographically, 10 of which ran through the liver parenchyma on a course
separated from the ligamentum teres. Seven of these 10 followed a tortuous course
just below the surface of the liver creating a ball or corkscrew-like pattern.
CONCLUSION: Shunts from the left portal branch are not uncommon and may represent
the only ultrasonographically detectable pathology in these patients. Recognition
of the typical pattern will facilitate their detection.
PMID- 9755710
TI - The efficacy of FP 736-04 in experimental liver cirrhosis.
AB - PURPOSE: To determine whether the uptake of FP 736-04, a hepatocyte-specific CT
contrast agent, is influenced by cirrhotic changes in the liver. MATERIAL AND
METHODS: Liver cirrhosis was induced by bile duct ligation (BDL) in Sprague
Dawley rats. Seventy-four animals were divided into three groups comprising: rats
with acute BDL; rats with chronic BDL; and normal controls. CT was performed
after i.v. infusion of FP 736-04 or saline at a dose of 2 ml/kg b.w., and the
mean attenuation in the liver and spleen was measured. The livers from the
chronic BDL group were taken for histopathological examination and the extent of
the disease was graded according to an arbitrary scale. RESULTS AND CONCLUSION:
There was a significant reduction of the native liver attenuation in both chronic
and acute BDL groups as compared with the normal controls. FP 736-04 was taken up
by the liver parenchyma with a similar degree of enhancement in all three groups.
PMID- 9755712
TI - Gadopentetate dimeglumine as a contrast agent in peripheral angioplasty. A case
report.
AB - Gadopentetate dimeglumine (Gd-DTPA) is widely used as a contrast agent in MR
imaging. We report on a case in which Gd-DTPA was used as the contrast agent
during angioplasty in a patient who had recently had an adverse reaction to a non
ionic iodinated contrast medium. Gd-DTPA allowed a diagnostic angiogram to be
performed with no side effects, and may thus be a useful contrast agent at
angioplasty in patients with contra-indications to iodinated contrast media.
PMID- 9755711
TI - Changes in tissue oxygen tension caused by contrast media injected into the
femoral artery of the dog.
AB - PURPOSE: To document changes in tissue oxygen tension as measured directly in an
area perfused with contrast medium. MATERIAL AND METHODS: Changes in tissue
oxygen tension in response to the injection of ionic and non-ionic contrast media
into the femoral arteries were measured in the femoral adductor (proximal) and
gastrocnemius (distal) muscles of 8 dogs. Amidotrizoic-acid and iopamidol were
injected in two different iodine concentrations (370 mg I/ml and 185 mg I/ml
respectively) and tissue oxygen tension in the proximal and distal muscles was
monitored continuously using polarographic needle electrodes. RESULTS AND
CONCLUSION: A transient decrease and subsequent increase of muscle tissue oxygen
tension were observed after the injection. The extent of these changes depended
on the concentration and osmolality of the medium. To minimize changes in
peripheral tissue oxygen tension, contrast media with low osmolality and low
concentration are recommended for femoral angiography.
PMID- 9755713
TI - Correlation between dose rate and T1 in blood at Gd-enhanced MR angiography.
AB - PURPOSE: To determine the correlation between dose rate and T1 in blood at Gd
enhanced MR angiography (MRA). MATERIAL AND METHODS: A test dose of contrast
agent was used to calculate the time delay between injection and arrival in the
abdominal aorta. The dose rate was expressed as ml.kg b.w.-1.s-1. The correlation
between dose rate and T1 was determined by varying the dose rate while keeping
the scanning and infusion times constant. The signal intensity in the abdominal
aorta was measured during the first pass of Gd and compared with markers of known
T1 values. RESULTS: A correlation between dose rate and T1 in blood was obtained.
CONCLUSION: A Gd dose rate of 0.01 ml.kg b.w.-1.s-1 gives a T1 in blood of 100
ms. This can be used to calculate the optimal pulse sequence for contrast
enhanced MRA.
PMID- 9755714
TI - Testicular microlithiasis--a possibly premalignant condition. Report of five
cases and a review of the literature.
AB - Testicular microlithiasis (TM) is a rare condition characterized by the presence
of multiple small intratesticular calcifications. The etiology is unknown but the
condition has been observed in a variety of different urological conditions. We
report on 5 cases diagnosed by ultrasonography at our departments from 1992 to
1994. A review of the literature plus our present 5 cases gives a total of 124
reported cases of TM. TM was associated with testicular malignancy in 44 patients
(35%) of whom 24 (19%) had a seminoma and 20 (16%) a non-seminoma. There were 4
reports of testicular malignancy developing in patients with a prior diagnosis of
TM. The condition should be considered premalignant and a careful follow-up of TM
patients is advocated.
PMID- 9755715
TI - Atypical CT findings of cervical lymphadenopathy due to Hodgkin's disease. A case
report.
AB - We describe a case of Hodgkin's disease with cervical lymphadenopathy which may
easily be confused with a granulomatous process both radiologically and
pathologically.
PMID- 9755716
TI - Bioreductive drugs into the next millennium.
PMID- 9755717
TI - Tirapazamine: laboratory data relevant to clinical activity.
AB - Tirapazamine (TPZ, SR 4233, WIN 59075, 3-amino-1,2,4-benzotriazine 1,4-dioxide,
Tirazone) is the lead compound in the benzotriazine di-N-oxide class of
bioreductive anticancer agents. Extensive preclinical testing has established
that the mechanism for the selective toxicity towards hypoxic cells is the result
of a one-electron reduction of the parent molecule to a free radical species that
interacts with DNA to produce single- and double-strand breaks and lethal
chromosome aberrations. It has also shown activity when combined with
fractionated irradiation and when combined with some chemotherapy agents,
particularly cisplatin and carboplatin. In this review we address those questions
about the drug that are most relevance to the clinical use of the compound. In
particular we review the evidence for the mechanism of action of the drug, and
also show that a large portion of the synergy seen in experimental tumors when
TPZ is combined with cisplatin is the result of a cellular interaction between
TPZ and cisplatin that depends on hypoxia. Also of relevance to clinical use is
whether the toxicity of TPZ is cumulative such as occurs with nitroimidazoles,
another class of hypoxia-activated agents. Such cumulative toxicity is not
evident. Finally, we present an analysis based on the area under the curve for
mice and humans that demonstrates that the doses being used in current Phase II
radiotherapy protocols and Phase III chemotherapy protocols should be sufficient
to produce clinical activity. We conclude that the preclinical data suggest that
it is likely that TPZ will be active in the clinic, particularly when combined
with cisplatin.
PMID- 9755718
TI - Enzymology of tirapazamine metabolism: a review.
AB - The enzymology of triapazamine (TPZ, SR 4233, WIN 59075, 3-amino-1,2,4
benzotriazene 1,4-dioxide, Tirazone) has been extensively studied in rodents and
to a lesser extent in human systems. While it is clear that the initial reductive
step in TPZ activation is enzyme-mediated, there is limited consensus in the
published literature as to the relative contributions of the cellular reductases
involved. Moreover, not only is the importance of subcellular localization for
these putative activating reductase(s) far from clear, but their activity
profiles in vivo are poorly defined. The same might also be said of the potential
detoxifying enzymes. This review will attempt to establish what common ground
exists regarding the enzymology of TPZ metabolism, and will relate the available
evidence to the enzyme profiles found in human cell lines in vitro, as well as in
xenograft models and human solid tumours.
PMID- 9755719
TI - 1,2,4-Benzotriazine 1,4-dioxides. An important class of hypoxic cytotoxins with
antitumor activity.
AB - Tirapazamine (1,2,4-benzotriazin-3-amine 1,4-dioxide, SR 4233, WIN 59075) is the
lead compound representing this class of anticancer drugs. It is also the first
compound to be introduced in the clinic as a pure bioreductive cytotoxic agent.
Tirapazamine represents a completely novel approach to the treatment of solid
tumors and has generated considerable interest, with research being carried out
on all aspects of the its anticancer activity. Phase III trials of tirapazamine
in combination with cisplatin (cDDP) have recently been concluded, and phase II
trials of triapazamine in combination with irradiation are presently being
performed. We developed a drug discovery program into this class of compounds
designed to produce derivatives with improved in vivo activity against solid
tumors. Based on the hypothesis that these compounds require bioreductive
activation for antitumor activity, the research was primarily directed at
producing analogues with greater electron affinity and improved aqueous
solubility. The in vitro and in vivo data for a variety of structural analogues
clearly show that 1,2,4-benzotriazine 1,4-dioxides have considerable potential as
anticancer agents. When their activity is compared directly with the activity
observed for triapazamine, the most promising series of analogues appears to be
the 3-alkyl-substituted derivatives, especially the 3-ethyl- and 3-(2'
methoxyethyl)-derivatives, SR 4895 and SR 4941 respectively.
PMID- 9755720
TI - Targeting hypoxia with a new generation of indolequinones.
AB - The indolequinone class of bioreductive alkylating agents has been developed to
effectively target the hypoxic cell population of the tumour. The mechanism of
activation of these prodrugs relies initially on the reduction of the p-quinonoid
moiety utilizing reductive enzymes to form electrophilic sites which can be
attacked by DNA to promote cell kill. Minor structural changes of the indole
'nucleus' may result in substantial favourable pharmacological and physiological
changes. Investigation of the mode of action of these compounds has resulted in
the use of novel indolequinones as 'trigger' molecules that can efficiently
release secondary agents into the hypoxic site of action.
PMID- 9755721
TI - Cyclopropyl indolequinones: mechanistic probes for bioreductive anticancer drug
action.
AB - A series of cyclopropyl indolequinones based on structures 5-7 was designed and
synthesized to probe the structural features essential for bioreductive
cytotoxicity. Ring opening of the cyclopropane ring under radical conditions was
demonstrated to be mechanistically feasible, and related to the involvement of
such one-electron processes in the cytotoxicity of cyclopropyl indolequinones
under hypoxic conditions.
PMID- 9755722
TI - Indolequinone bioreductive drugs: kinetic factors which influence selectivity for
hypoxia.
AB - The factors influencing the kinetics of the oxygen-sensitive reduction of
indolequinones, including those bearing leaving groups in the (indol-3-yl)methyl
position, have been studied. The hydroquinones derived from some representative
indolequinones were found to autoxidize slowly in oxygenated solution at rates
(effective rate constant with O2 approximately 40-300 M-1 s-1) that cannot
compete with the reductive elimination of leaving groups. The rates of reaction
between hydroquinone and O2 were even slower in the presence of approximately 4
microM superoxide dismutase (effective rate constant approximately 2-7 M-1 s-1),
indicating the role of superoxide radicals in hydroquinone autoxidation. Since
the release of the leaving groups from the hydroquinones is not significantly
oxygen-sensitive, tumour selectivity requires specific reduction by enzymes that
are overexpressed in some tumours. Conversely, the release of leaving groups from
semiquinone radicals is inhibited by oxygen too efficiently unless the
semiquinone reacts with targets on a timescale of milliseconds. Modification of
redox properties has been explored with the aim of changing this oxygen
sensitivity. The new 2-phenylindolequinones are approximately 60-100 mV higher in
reduction potential than 2-alkyl derivatives but this is insufficient to decrease
the rate of electron transfer from semiquinone to oxygen to a degree which might
confer hypoxia-selective cytotoxicity. These results are discussed in the context
of toxicity of EO9 and related compounds towards hypoxic rather than anoxic
cells.
PMID- 9755723
TI - The 5-nitrofuran-2-ylmethylidene group as a potential bioreductively activated
prodrug system for diol-containing drugs.
AB - Acid-catalysed condensation of 5-nitrofuran-2-carboxaldehyde with 1-phenylethane
1,2-diol and with 2,2-dimethyl-1-phenylproane-1,3-diol in boiling benzene gave
the expected cyclic nitrofuranyl acetals. Biomimetic reduction of these acetals
with sodium borohydride in the presence of palladium triggered release of the
parent diols. Thus these nitrofuran acetals may have potential for applications
as prodrugs for selective release of diol-containing drugs in hypoxic solid
tumours.
PMID- 9755724
TI - Radiation-activated prodrugs as hypoxia-selective cytotoxins: model studies with
nitroarylmethyl quaternary salts.
AB - Bioreductive drugs are designed to be activated by enzymatic reduction in hypoxic
regions of tumours, but activation of these drugs is not always fully suppressed
by oxygen in normal tissues. A further limitation is that bioreductive drug
activation depends on suitable reductases being expressed in the hypoxic zone.
This essay proposes an alternative approach in which prodrugs are reduced, and
thereby activated, in hypoxic regions by ionizing radiation rather than by
enzymes. This strategy is theoretically attractive, but design requirements for
such radiation-activated cytotoxins are challenging. In particular, the reducing
capacity of radiation at clinically relevant doses is small, which necessitates
the development of prodrugs capable of releasing very potent cytotoxins
efficiently in hypoxic tissue. It is shown that nitroarylmethyl quaternary (NMQ)
salts possess many of the features required of a radiation-activated prodrug. In
some heterocyclic NMQ compounds the cytotoxicity of the latent cytotoxic amine
effector is suppressed by > 100-fold in the prodrug form, and the effector is
released rapidly by fragmentation following reduction by a single electron.
Appreciable cytotoxic activation of NMQ prodrugs can be achieved by irradiation
at clinically relevant doses in anoxic plasma. Some of the further drug design
challenges required to develop a clinical agent based on this approach are
outlined.
PMID- 9755725
TI - Use of 2-nitroimidazoles as bioreductive markers for tumour hypoxia.
AB - Tumour hypoxia is thought to contribute to some failures of radiotherapy to
achieve local control. Polarographic measurements of tumour oxygenation have been
shown to predict clinical response to radiotherapy and patient survival. Hypoxia
is also involved in many common types of normal tissue morbidity. However, at
present there is no widely used method of measuring hypoxia in the clinic, or for
individualizing therapy on the basis of tumour or tissue oxygenation. The
bioreductive metabolism of 2-nitroimidazoles provides a way of labelling hypoxic
cells in vivo and a variety of isotopic labels have been proposed for the non
invasive detection of bound metabolites of these markers. Several 2
nitroimidazoles with immunologically identifiable side-chains have been described
and conventional immunostaining procedures can be used to locate their
metabolites, bound to hypoxic cells in histological sections. Use of fluorescent
immunoreagents allows flow cytometric assessment of hypoxia and multiple colour
fluorescent staining allows hypoxia to be correlated with other markers on a cell
by cell basis. 2-Nitroimidazole hypoxia markers show considerable promise for
clinical use in diagnosing hypoxia and their use could allow rational application
of hypoxia-related therapies to those patients most likely to benefit from them.
PMID- 9755726
TI - Preclinical development and current status of the fluorinated 2-nitroimidazole
hypoxia probe N-(2-hydroxy-3,3,3-trifluoropropyl)-2-(2-nitro-1-imidazolyl)
acetamide (SR 4554, CRC 94/17): a non-invasive diagnostic probe for the
measurement of tumor hypoxia by magnetic resonance spectroscopy and imaging, and
by positron emission tomography.
AB - Hypoxia occurs to a variable extent in a vast majority of rodent and human solid
tumors. It results from an inadequate and disorganized tumor vasculature, and
hence an impaired oxygen delivery. A probe for the non-invasive detection of
tumor hypoxia could find important utility in the selection of patients for
therapy with bioreductive agents, anti-angiogenic/anti-vascular therapies and
hypoxia-targeted gene therapy. In addition, tumor hypoxia has been shown to
predict for treatment outcome following radio- or chemotherapy in human cancers,
the underlying mechanism for which may involve hypoxia driving genetic
instability and resulting tumor progression. Beyond oncology, utility can also be
envisaged in stroke, ischemic heart disease, peripheral vascular disease,
arthritis and other disorders. Design, validation, preclinical development and
current status of a fluorinated 2-nitroimidazole, N-(2-hydroxy-3,3,3
trifluoropropyl)-2-(2-nitro-l-imidazolyl) acetamide (SR 4554, CRC 94/17), which
has been rationally designed for the measurement of tumor hypoxia by magnetic
resonance spectroscopy (MRS) and imaging (MRI), are reviewed. Application in
positron emission tomography (PET) detection is also proposed. Design goals were:
(i) a nitro group with appropriate redox potential for selective reduction and
binding in hypoxic tumor cells; (ii) hydrophilic/hydrogen bonding character in
the side chain to limit nervous tissue penetration and prevent neurotoxicity; and
(iii) three equivalent fluorine atoms to enhance MRS/MRI detection, located in a
metabolically stable position. Reduction of SR 4554 by mouse liver microsomes was
dependent on oxygen content, with a half-maximal inhibition at 0.48 +/- 0.06%. SR
4554 underwent nitroreduction by hypoxic but not oxic tumor cells in vitro and
electron energy loss spectroscopic analysis showed selective retention in the
hypoxic regions of multicellular tumor spheroids. Pharmacokinetic design goals
were met. In particular, low brain tissue concentrations were seen in contrast to
excellent tumor levels, as measured by high performance liquid chromatography.
The extent of this restricted entry to brain tumor was surprising given the
overall octanol/water partition coefficient and was attributed to the
hydrophilic/hydrogen bonding character of the side chain. Quantitative MRS was
used to assess the retention of 19F signal in murine tumors and human tumor
xenografts. The 19F retention index (FRI; ratio of 19F signal levels at 6 h
relative to that at 45 min) ranged from 0.5 to 1.0 and 0.2 to 0.9 for murine
tumors and human xenografts respectively. The correlation between SR 4554
retention and pO2 was not a linear one, but when FRI was > 0.5, the % pO2 < or =
5 mmHg was always > 60%, indicating that high FRI was associated with low levels
of oxygenation. Finally, whole body 19F-MRI in mice demonstrated that SR 4554 and
related metabolites localized mainly in tumor, liver and bladder regions. A
selective MRS signal was readily detectable in tumors at doses at least 7-fold
lower than those likely to cause toxicity in mice. We conclude that proof of
principle is established for the use of SR 4554 as a non-invasive MRS/MRI probe
for the detection of tumor hypoxia. Based on these promising studies, SR 4554 has
been selected for clinical development.
PMID- 9755727
TI - Altered efficacy and selectivity of tyrosine kinase inhibitors of the activated
states of protein tyrosine kinases.
PMID- 9755728
TI - Picture of the month. Cutaneous larva migrans (creeping eruption).
PMID- 9755729
TI - Change in coronary risk factor levels in couples after lifestyle intervention.
PMID- 9755730
TI - Chiropractic: a fantasy and delusion.
PMID- 9755731
TI - Assessing quality of care via HEDIS 3.0. Is there a better way?
AB - Patients, employers, and third-party payers are all calling for improved measures
of health care quality. This has led to the development of "report cards,"
assessments that are many times applied not just to health plans but also to
providers. One attempt at creating a standardized set of quality and
effectiveness measures is the Health Plan Employer Data and Information Set
(HEDIS). The HEDIS measures are based primarily on analyses of administrative
data sets. Problems with HEDIS measures, including the probability that plans
will use different data collection methods and a lack of risk adjustment, may
result in incorrect conclusions about the quality of care delivered by various
providers. An alternative method of standardized surveys is proposed that will
overcome many of the limitations of the current HEDIS measures, provide outcome
rather than process data, and provide data for developing interventions to
improve quality.
PMID- 9755732
TI - Measuring the health of seniors.
PMID- 9755733
TI - The patient self-determination act and advance directive completion in nursing
homes.
AB - OBJECTIVES: To assess the prevalence of advance directives among nursing home
residents before and after passage of the Patient Self-Determination Act (PSDA)
and to identify factors associated with advance directive completion. DESIGN:
Prestudy and poststudy nursing home admissions using medical record reviews and a
companion cross-sectional survey of alert and oriented residents. SETTING: Six
nursing homes in Connecticut. PARTICIPANTS: Residents (N = 635) from 6 randomly
chosen nursing homes in the greater Hartford and greater New Haven areas. MAIN
OUTCOME MEASURES: The existence of a documented advance directive, the timing of
advance directive completion, and reported reasons for completion and
noncompletion. RESULTS: The prevalence of advance directives documentation in
nursing home medical records has increased significantly since the implementation
of the PSDA (4.7% [14/300] before vs 34.7% [104/300] after PSDA; odds ratio,
10.84; P < .001). The increase in documented advance directives was significant
after controlling for sociodemographic and health status factors (odds ratio,
11.5; P < .001). Residents admitted to the nursing homes from hospitals (vs from
their home or other source), residents with more education, and residents paying
privately for nursing home care (vs using Medicare or Medicaid benefits) were
more likely to have documented advance directives. Younger residents (aged < 75
years) were less likely than older residents to have completed a directive. Among
the 35 interviewed residents, the most common reason for completing an advance
directive was experience with a prolonged death of a friend or family member.
Only 1 of the interviewed residents reported that the information provided under
the PSDA at the time of admission was an important factor in choosing to complete
an advance directive. CONCLUSIONS: Nearly 35% of the residents in the post PSDA
cohort had an advance directive documented in the medical record. Most residents
with advance directives had completed them more than 6 months before the nursing
home admission. The major effect of the PSDA for nursing homes has been to
enhance the documentation of existing advance directives. Little evidence exists
that providing advance directive information at the time of nursing home
admission has enhanced the completion of an advance directive after admission.
PMID- 9755734
TI - Transdermal nicotine therapy and primary care. Importance of counseling,
demographic, and participant selection factors on 1-year quit rates. The Nebraska
Primary Practice Smoking Cessation Trial Group.
AB - OBJECTIVE: To evaluate the smoking cessation efficacy of nicotine patch therapy
as an adjunct to low-intensity, primary care intervention. DESIGN: Randomized,
placebo-controlled, double-blind, multisite trial. SETTINGS: Twenty-one primary
care sites in Nebraska. PATIENTS: A total of 369 smokers of 20 or more cigarettes
per day. INTERVENTION: Two brief primary care visits for smoking intervention
with 10 weeks of active or placebo-patch therapy. MAIN OUTCOME MEASURES:
Confirmed self-reported abstinence 3, 6, and 12 months after the quit day.
RESULTS: Compared with placebo control subjects, participants assigned nicotine
patches had higher 3-month (23.4% vs 11.4%; P < .01) and 6-month (18.5% vs 10.3%;
P < .05) abstinence rates. The 1-year abstinence rates for the active and placebo
patch groups were 14.7% and 8.7%, respectively (P = .07). Of smokers aged 45
years and older, 9 (18.8%) of 48 using active patches compared with 0 of 31 using
placebo patches achieved 12-month abstinence (chi 2 = 6.56; P < .05). Among those
with high nicotine dependency scores (Fagerstrom score > or = 7), 1-year
abstinence rates were significantly higher in the nicotine patch group (19.1%)
compared with the placebo group (5.0%) (chi 2 = 10.7; P = .001). However, there
was no significant difference in 1-year quit rates for participants with low
Fagerstrom scores (< 7). CONCLUSIONS: Nicotine patch therapy enhanced 6 month
quit rates as an adjunct to brief primary care intervention. The highest quit
rates were achieved by participants who specifically contacted the site to enroll
in the study or to obtain a prescription for nicotine patches. Differences in
participant selection factors may account, in part, for the lower smoking
cessation rates associated with primary care intervention. Duration of
counseling, patient age, and Fagerstrom scores may be important factors related
to the long-term smoking cessation success of nicotine patch therapy.
PMID- 9755735
TI - Religious beliefs and practices in family medicine.
AB - OBJECTIVES: To determine whether the religious beliefs and behaviors of family
medicine outpatients differed from those of their physicians and whether
patients' religiousness affects their expectations of their physicians regarding
religious matters. DESIGN: A survey study was performed on a consecutive sample
of 380 family medicine clinic outpatients and 31 family medicine faculty and
residents in 2 family medicine residency programs. SETTING AND SUBJECTS:
Outpatients were recruited from an outpatient clinic of a family medicine
residency program in North Carolina. Family medicine physicians and residents
were recruited from this program and another in Texas. MAIN OUTCOME MEASURES:
Scores were obtained from the Springfield Religiosity Scale, the Hoge Intrinsic
Religiosity Scale, and a religious beliefs questionnaire designed for this study.
RESULTS: Absence of religious affiliation was more common for physicians than
patients. Physicians were less likely than patients to pray privately and less
likely to hold intrinsic religious attitudes. Patients were more likely than
physicians to be interested in their own physician's religious beliefs, more
likely to feel that they should know their physician's religious beliefs, and
more likely to want their physician to pray with them under certain
circumstances. When sex and age were controlled, some of these differences
disappeared. When compared with patients, physicians tended to be younger and
male--characteristics inversely associated with religious belief and practice.
Regardless of sex or age, however, the more religious the patients, the more
likely the desire to know their physician's religious beliefs and share their own
religious beliefs. CONCLUSIONS: Patients are more involved in religious beliefs
and practices than physicians, a finding partially explained by age and sex. The
more religious the patients, the more important it is for them to know their
physician's beliefs, share their beliefs with their physician, and want their
physicians to pray with them.
PMID- 9755736
TI - Knowledge of periconceptional folic acid for the prevention of neural tube
defects. The missing links. Northeastern Ontario Primary Care Research Group.
AB - BACKGROUND: Periconceptional folic acid supplementation is effective in
preventing primary and secondary neural tube defects (NTDs) and other congenital
defects. However, debate exists regarding the effectiveness of public and
physician education on patient knowledge and compliance. OBJECTIVE: To examine
the level of knowledge about the usefulness of periconceptional folic acid
supplementation in a sample of patients from primary care practices. DESIGN:
Cross-sectional survey. A confidential, anonymous questionnaire was completed by
patients before physician encounters. A maximum of 20 consecutive female patients
from each of 3 age groups (16-24, 25-32, and 33-40 years) were recruited from
each primary care practice. SETTINGS: Twenty-two Canadian teaching practices
affiliated with the Northeastern Ontario Primary Care Research Group. OUTCOME:
Women's knowledge of periconceptional folic acid supplementation for the
prevention of NTDs. RESULTS: Of 1125 eligible female patients between the ages of
16 and 40 years visiting their family physician in 1996, 1124 (99.9%) completed
the questionnaire. General awareness of NTDs was high (62.7%); however, knowledge
that these defects were preventable was lower (22.5%). Only 7.8% of the women
made the association between folic acid intake and NTDs. The specific knowledge
that NTDs could be prevented with folic acid supplementation before conception
was identified by 1.8% of the sample. Pregnant participants were at least twice
as likely to be informed about the link. Interpractice variability existed with
respect to knowledge of folic acid supplementation. CONCLUSION: Knowledge of
periconceptional folic acid supplementation for the prevention of NTDs was low in
this sample and is likely to be reflected in missed opportunities to prevent an
important class of congenital malformations.
PMID- 9755737
TI - Relapse of depression in primary care. Rate and clinical predictors.
AB - OBJECTIVE: To determine the clinical predictors and rate of relapse for major
depression in primary care. DESIGN: A cohort study of subjects in 2 randomized
trials of depressed patients diagnosed and prescribed antidepressant medicine by
primary care physicians. Baseline, 7-month, and 19-month assessments were
conducted. SETTING: A large primary care clinic of a staff-model health
maintenance organization. PATIENTS: Two hundred fifty-one primary care patients
who did not satisfy Diagnostic and Statistical Manual of Mental Disorders,
Revised Third Edition (DSM-III-R) criteria for major depression at 7 months. MAIN
OUTCOME MEASURES: Relapse was defined as (1) satisfying DSM-III-R criteria for
major depression at 19 months, or (2) reporting an interval episode of 2 weeks or
more of depressed mood and symptoms between 7 and 19 months. Predictors examined
included demographic characteristics, medical comorbidity, disability, and
psychological symptoms. Depressive symptoms were measured by Inventory of
Depressive Symptoms and Hopkins Symptoms Checklist. RESULTS: Of the patients,
37.1% reported relapse of depression in the 12-month relapse-risk period. The 2
major risk factors associated with relapse were (1) persistence of subthreshold
depressive symptoms 7 months after the initiation of antidepressant therapy (odds
ratio, 3.3; 95% confidence interval, 2.74-3.93) and (2) history of 2 or more
episodes of major depression, or chronic mood symptoms for 2 years (odds ratio,
2.1; 95% confidence interval, 1.41-2.76). Patients with both risk factors were
approximately 3 times more likely to relapse than patients with neither.
CONCLUSIONS: The relapse rate among primary care patients treated for depression
approached that of specialty samples, with more than one third reporting relapse
in 1 year. Clinical characteristics can help target high-risk patients for
relapse prevention efforts.
PMID- 9755738
TI - False positives, false negatives, and the validity of the diagnosis of major
depression in primary care.
AB - OBJECTIVE: To explore the issues of diagnostic specificity and psychiatric
"caseness" (i.e., whether a patient meets the conditions to qualify as a "case"
of a disease or syndrome) for major depression in the primary care setting.
DESIGN: A cross-sectional study comparing the demographic, clinical, and mental
health characteristics of patients identified as depressed by their family
physicians with those meeting diagnostic criteria for major depression on the
criterion standard Structured Clinical Interview for Diagnostic and Statistical
Manual of Mental Disorders, Revised Third Edition. SETTING: The offices of 50
family physicians from private and academic practice in southeast Michigan.
PATIENTS: A total of 1580 consecutive adult patients being seen for routine
primary care services, from whom a weighted sample of 372 patients completed a
set of mental health screening and diagnostic instruments. MAIN OUTCOME MEASURES:
Patients were assigned to 1 of 4 groups (true positive, false positive, false
negative, and true negative) based on clinician identification and Structured
Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders,
Revised Third Edition diagnosis. Differences between the 4 groups in demographic
and clinical characteristics, scores on mental health instruments and mental
health history were explored. RESULTS: Physician identification of depression was
strongly associated with increased familiarity with the patient and the presence
of suggestive clinical cues, such as history of or treatment for depression,
patient distress, and presence of vegetative symptoms. Patients in the false
positive group displayed significantly higher levels of distress and impairment
and were significantly more likely to have a history of mental health problems
and treatment than were those in the true-negative group. The 2 "misidentified"
groups, false positives and false negatives, were indistinguishable in their
clinical characteristics (impairment, distress, or mental health history). Both
groups' scores occupied the middle ground between true positives and true
negatives on most clinical characteristics. Physicians appeared to discriminate
between these 2 groups on the basis of their knowledge of the patient's clinical
history. CONCLUSIONS: Misidentification of depression in primary care may be in
part an artifact of the use of the psychiatric model of caseness in the primary
care setting. Our results are most consistent with a chronic disease-based model
of depressive disorder, in which patients classified as false positive and false
negative occupy a clinical middle ground between clearly depressed and clearly
nondepressed patients. Family physicians appear to respond to meaningful clinical
cues in assigning the diagnosis of depression to these distressed and impaired
patients.
PMID- 9755739
TI - Managing our depressed patients. Gold standards vs higher standards.
PMID- 9755740
TI - Diagnostic efficiency of home pregnancy test kits. A meta-analysis.
AB - OBJECTIVE: To assess the diagnostic efficiency of home pregnancy test (HPT) kits.
DATA SOURCES: A literature search of English-language studies was performed with
MEDLINE and a review of bibliographies. STUDY SELECTION: Studies were included if
HPT kits were compared with a criterion standard (laboratory testing), if they
used appropriate controls, and if data were available to determine sensitivity
and specificity. DATA EXTRACTION: Two investigators independently extracted data,
and disagreement was resolved by consensus. Sensitivity, specificity, and an
effectiveness score (a measure of the discriminatory power of the test, with
higher scores implying greater effectiveness) were calculated. DATA SYNTHESIS:
Five studies evaluating 16 HPT kits met the inclusion criteria. The range of
sensitivities for HPT kits was 0.52 to 1.0. In studies where urine samples
obtained by the investigators were tested by volunteers, sensitivity was 0.91
(95% confidence interval [CI], 0.84-0.96). However, the sensitivity was less in
studies where subjects were actual patients who performed the test on their own
urine samples (sensitivity, 0.75 [95% CI, 0.64-0.85]). The test effectiveness
score was 2.75 (95% CI, 2.3-3.2) for studies where subjects were volunteers but
deteriorated to 0.82 (95% CI, 0.4-1.2) for studies with actual patients.
CONCLUSIONS: The diagnostic efficiency of HPT kits is greatly affected by
characteristics of the users. Despite the popularity of these kits, the
relatively low effectiveness scores of these kits when used by actual patients
are of concern. We suggest that manufacturers of HPT kits publish results of
trials in actual patients before marketing them to the general public.
PMID- 9755741
TI - Are serotonin uptake inhibitors useful in chronic pain syndromes such as
fibromyalgia or diabetic neuropathy?
PMID- 9755742
TI - Narcolepsy. Signs, symptoms, differential diagnosis, and management.
AB - Narcolepsy is a chronic neurologic disorder characterized by excessive daytime
sleepiness and cataplexy and less often by hypnagogic hallucinations and sleep
paralysis. While patients report excessive daytime sleepiness and cataplexy as
the more frequent symptoms of this condition, excessive daytime sleepiness is
generally believed to be the most debilitating. Narcolepsy often is undiagnosed
or misdiagnosed for a variety of reasons. Although confirmation of an initial
diagnosis requires monitoring of physiologic variables conducted at a sleep
center by specialists, the primary care physician has a critical role in the
identification and management of this incurable affliction. This article provides
recommendations for the diagnosis and management of narcolepsy. The cataplexy
associated with narcolepsy can be managed with tricyclic antidepressants. The
excessive sleepiness is managed with stimulants but newer agents, such as
modafinil, which will be marketed as Provigil, and selegiline hydrochloride, with
fewer adverse effects and less abuse potential, may offer means of promoting
daytime wakefulness. Groups such as the National Sleep Foundation, Washington,
DC, and the Narcolepsy Network, Cincinnati, Ohio, can provide patients with
needed support and information.
PMID- 9755743
TI - Use of a structured encounter form to improve well-child care documentation.
AB - OBJECTIVE: To determine if a structured encounter form for well-child care
improves documentation of well-child care. DESIGN: Retrospective medical record
review of a before-and-after trial. SETTING: Family practice residency clinic
serving a primarily low-socioeconomic urban population. PATIENTS: Children
younger than 6 years receiving well-child care visits. INTERVENTION: Detailed
checklists were developed and implemented in 1994 for each of 12 well-child
examinations for the assessment of children aged 2 weeks to 5 years based on
recommendations from the American Academy of Pediatrics and the US Preventive
Services Task Force. MAIN OUTCOME MEASURES: Documentation of multiple aspects of
well-child care, including developmental assessment, safety and nutrition
counseling, and laboratory tests for 6-month periods in 1993 and 1994, before and
after implementation of the structured encounter form. RESULTS: A total of 842
well-child visits were reviewed. Documentation improved significantly with the
use of the encounter form for 19 of the 23 aspects of well-child care that were
studied. Screening test rates were less than optimal despite the encounter form.
CONCLUSIONS: The structured encounter form was very effective in improving
documentation of almost all aspects of well-child care. However, effective
communication is needed among physicians, nurses, and parents to ensure optimal
screening test rates.
PMID- 9755744
TI - Elderly patients' preferences for long-term life support.
AB - OBJECTIVE: To study elderly patients' preferences regarding mechanical
ventilation and tube feeding and to compare their preferences for short-term use
with their preferences for long-term use of these life support interventions.
DESIGN: Interviews with patients by clinicians during routine office visits.
SETTING: Hospital-based, primary care geriatrics clinic in downtown Denver, Colo.
PATIENTS: Two hundred eighty-seven elderly persons (mean age, 77 years; range, 60
99 years). MAIN OUTCOME MEASURES: Preferences to use or withhold: (1) short-term
mechanical ventilation; (2) long-term mechanical ventilation; (3) short-term tube
feeding; and (4) long-term tube feeding. RESULTS: Of the total sample, 253
patients (88%) would prefer short-term mechanical ventilation if the chance of
recovering was reasonably good but only 11 (3.5%) would prefer long-term
mechanical ventilation. One hundred eighty-nine (65%) would prefer short-term
tube feeding, but only 13 (4.5%) would prefer long-term tube feeding in the
setting of significant cognitive impairment. CONCLUSIONS: Most elderly persons
opt for short-term mechanical ventilation or tube feeding if the chance of
recovering is reasonably good. Only a small minority would opt for long-term
mechanical ventilation or tube feeding.
PMID- 9755745
TI - One more test.
PMID- 9755746
TI - [Role of intravascular brachytherapy in the prevention of vascular restenosis
after angioplasty].
AB - About 30% of patients who underwent percutaneous transluminal coronary
angioplasty show evidence of restenosis, which appears to be independent of the
angioplasty method used. The restenosis is due of two factors, firstly migration
of smooth vascular muscle cells of the vascular media to the intima and
multiplication which lead to the formation of a neo-intima. Irradiation limits
the proliferation by acting of the cells in the mitotic stage. The vascular
target volume is not very thick and is difficult to define it, that why
brachytherapy seems to be the best procedure to prevent restenosis. However, the
development of this treatment present many difficulties. Different irradiation
techniques have been studied. Such techniques include catheter containing
radioactive sealed source, radioactive stent, or balloon containing radioactive
liquid inside. Each of these methods have their own advantages, inconveniences,
problems and risks. Radioisotope may be either beta or gamma emitters. Gamma
emitter presents problems for radioprotection but the satisfactory dose
distribution may be difficult to obtain using beta emitter. Choice of dose, dose
rate and delay between the end of angioplasty and the beginning of brachytherapy
is subject to some discuss. Animal experiments using radioisotope have shown
reduction in cell proliferation. Human trials showed feasibility, safety of the
method and real impact on restenosis prevention. However, long-term efficacy has
not been proved because the follow-up of the patients is too short. A randomized
trial of 192Ir brachytherapy for prevention of restenosis has recently shown the
efficacy in short and median term. However, long term efficiency and secondary
effects have not yet been established as the follow up time of this study is
still too short. That is why, collaboration between cardiologists and
radiotherapists and physicists is indispensable to enable the development of an
optimal technique.
PMID- 9755747
TI - [Radiotherapy of stage T1-T2 M0 prostatic adenocarcinoma. Analysis of the
carcinologic results of a multicenter study of 610 patients. Groupe Radiotherapie
de la Commission de Cooperation Medicale Intercentres (CCMI)].
AB - PURPOSE: Retrospective analysis of the results of radiotherapy in localized
prostatic adenocarcinoma. Complications were excluded. PATIENTS AND METHODS: Six
hundred-and-ten T1-T2 adenocarcinomas of the prostate were treated with
continuous courses of external beam radiation therapy in 19 participating
Institutes between January 1983 and January 1988. The mean follow-up was 10.4
years; the mean age of patients at the beginning of radiotherapy was 68.5 years.
RESULTS: A 10-year, local control had been achieved in 86% of T1-T2 (81.4% for
T2). The 5- and 10-year metastatic relapse rates were 25.3% and 30% (29% and
38.1% for T2), respectively. At 10 years, 62.4% of T1-T2 were recurrence-free;
overall survival rate was 45.8% and cause-specific survival rate was 70.5%; 29.9%
of T1-T2 patients were alive and disease-free. T category (TNM), pathologic
grade, pelvic lymph node status, local tumor control, and obstructive ureteral
symptoms were correlated with survival. The influence of pelvic nodes radiation,
dose, overall treatment time, previous endocrine treatment, and transuretral
resection was not significant for disease-free survival (alive and disease-free)
and other endpoints. CONCLUSION: There was no difference between the French
series (1975-1982 and 1983-1988). The results of the literature are comparable to
ours. As far as prognostic factors are concerned, this report provides evidence
that the explainable variables which influence survival depend on the tumor and
patient status.
PMID- 9755749
TI - [Retrospective analysis of the reproducibility of the daily set-up of the
irradiation fields of cancer of the rectum using a megavoltage imaging system].
AB - PURPOSE: To evaluate a ionization chamber on-line portal imaging system in
routine clinical radiotherapy of rectum cancers. PATIENTS AND METHODS: Megavolt
portal images were obtained using a fast electronic megavoltage radiotherapy
imaging system in 13 cases of pelvic fields. A total of 208 portal images and 13
simulator films were used to determine the values of set-up deviations in the X-Z
directions of a fixed co-ordinate system, and of the rotation fields (R).
RESULTS: Mean standard deviations of the difference between simulation and
treatment images were 3.2 mm and 0.9 mm for X and Z, 3.6 mm for the rotation
fault. The standard deviations were, respectively, 7.1 mm, 7.1 mm and 1.5 mm. The
cumulative frequency distributions revealed that 80% and 95% of the absolute
differences were less than 10 mm and 17.5 mm, respectively. CONCLUSION: These
results indicate the difficulty of a reproducible daily set-up. A weekly control
could be proposed in order to increase the quality of pelvic site treatment. The
introduction of masks to improve the set-up is also discussed.
PMID- 9755748
TI - Radical radiotherapy of localised prostate cancer: the relationship between
radiation dose and survival.
AB - PURPOSE: This retrospective study aims to define the effects of different
radiation dose levels on survival, local control and toxicity in a series of 208
patients with localised prostate cancer consecutively treated with radical
radiation therapy. PATIENTS AND METHODS: From 1982 through 1996, 365 patients
with prostate cancer have been consecutively treated with radical radiotherapy in
Florence (n = 306) and Arezzo (n = 59). The 208 cases treated until January 1994
with Stage B (125/208, 60%) and C (83/208, 40%) are the objects of the present
study. The treatment was most often limited to the prostatic area (81%), using a
four-field "box technique" and 25 MV photon beams, up to a total dose of 60-65 Gy
(21% of the patients), of 66-69 Gy (26%) and of 70 Gy (53%); conventional
fractionation was used (fractional dose: 2 Gy; five fractions/week). Hormonal
therapy was also given to 39% of the cases. The possible relationship between
dose, stage, grading and survival has been analysed. The survival figures and the
types of relapse observed (prostatic, lymphnodal or "biochemical") have been
analysed also according to the extent of the target volume and to the prostate
specific antigen (PSA) value at diagnosis, in the entire series or in selected
subgroups. RESULTS: In the whole series and also after radiation alone, the
patients with Stage B, with more differentiated tumours and those treated with
higher doses to the prostate obtained significantly better survival results.
Multivariate analysis confirmed that the dose level has an independent prognostic
value. The use of a limited target volume did not produce an excess of pelvic
lymphnodal failures. Among the patients more recently treated with radiation
alone, the PSA level at diagnosis is strongly related with the risk of local and
"biochemical" failure, and also with the relapse-free survival. Toxicity was
acceptable, also for the patients treated with higher doses, but late treatment
related damage is more frequent in patients treated on larger volumes.
CONCLUSION: The results of this retrospective analysis confirm the good results
of small volume, high dose radiation therapy of prostatic cancer, even taking
into account the possible biases due to the retrospective nature of the study,
and the relevance of the PSA level at diagnosis to define the risk of local
failure.
PMID- 9755750
TI - [Tolerance and role of irradiation in the treatment of epithelial cancer of the
ovary].
AB - PURPOSE: In a retrospective analysis, our aim was to evaluate the immediate
tolerance and the early and late complications of abdomino-pelvic radiotherapy in
the Centre Alexis-Vautrin (France). PATIENTS AND METHODS: From 1st January 1983
to 31st December 1993, 117 patients were treated at Centre Alexis Vautrin in
Nancy for epithelial ovarian cancer by abdominal and/or pelvic irradiation after
surgery. They were aged from 24 to 85 with a median of 56 years. There were ten
patients with stage I (9%), 28 patients with stage II (24%), 60 patients with
stage III (61%) and 19 patients with stage IV (16%) disease. Results of surgery
were determined as follows: satisfactory with absence of tumoral residuum in 26%
cases (30 patients) and with residuum inferior to 20 mm in 46% cases (52
patients; incomplete in 26% cases (31 patients) either because of residuum
superior in 20 mm and/or incomplete surgery; and not evaluable in 3% cases (four
patients). Seventy-seven patients were sent to the Centre for postoperative
treatment (66% patients of the series), 48 of them (62.4%) after non-satisfactory
surgery, 29 after satisfactory surgery (37.6%). Chemotherapy was administered to
only 104 patients (89% cases), and contained platinum salts and cyclophosphamid
for 87% of these patients. Fourteen patients (12%) received a single irradiation
dose after surgery: three in stage I, three with poor evaluation of the disease
in the initial stage, three with medical contraindications to chemotherapy
treatment, six with contraindications due to advanced age (?? Makes 15 ).
Histologically, 46% of patients had a serous adenocarcinoma, 9% a mucinous
adenocarcinoma, 11% an endometrioid adenocarcinoma, 2% a clear cell
adenocarcinoma, 1% an undifferentiated adenocarcinoma, and 31% an epithelial
carcinoma without any other indication. The histological grade which was recently
introduced was rarely indicated. Complementary radiotherapeutic treatment
consisted of pelvic irradiation for 14 patients (12%), abdomino-pelvic
irradiation for 63 patients (54%), and total abdominal irradiation with a pelvic
boost for 40 patients (34%). RESULTS: The immediate tolerance to irradiation can
be considered as globally satisfactory since 9% of the patients (ten cases) had
no problems and 64% of the patients developed a minor intolerance easily
controlled by symptomatic treatments. There were also digestive complications:
nausea, vomiting and diarrhea for 66% of the patients (50 cases); to a lesser
extent, 20% of the cases experienced associated digestive and hematological
complications (15 patients); 9% isolated hematological troubles such as anemia
(seven patients); 4% digestive complications (three patients) and 1%
hematological and urinary digestive troubles (one patients). Late irradiation
sequelae were evaluated for 89 patients with a follow-up lasting from 4 months to
11 years. Sixty-six patients had no sequelae, eleven patients had minor
tolerability problems--mainly digestive for more than half of them. Five patients
presented severe complications, including hematological problems such as chronic
thrombopenia in two cases, urinary-problems in two other cases, and one patient
presented with a case of histologically proven malabsorption. Two patients
presented major problems; one case of radic cystitis and one of radic bowel. Two
patients died of iatrogenic causes: one of induced leukemia, the other of
treatment-induced digestive and renal complications. The overall survival rate
was 30% at 5 years and 22% at 10 years. It was 90% at 5 and 10 years for stage I
patients, 60% at 5 years and 30% at 10 years for stage II patients, 22% at 5
years and 8% at 10 years for stage III patients, and finally 10% at 5 years for
stage IV patients. CONCLUSION: In this retrospective analysis of 117 epithelial
ovarian cancers, treated over 10 years and which all received pelvic and/or
abdominal irradiation, we can conclude that this treatment is globally well
tolerated and that it yields a
PMID- 9755751
TI - [Radiosurgery of single brain metastasis without combined total cerebral
irradiation. Results of a consecutive series of 12 cases].
AB - PURPOSE: To evaluate the usefulness of radiosurgery without whole brain
irradiation for a solitary brain metastasis. PATIENTS AND METHODS: Between
December 1994 and November 1996, 12 patients were treated for a single brain
metastasis by radiosurgery alone. Median age was 53, and 10 patients had a
Karnofsky performance status above 70. Half the patients had active extracranial
disease at the time of radiosurgery. Stereotactic radiosurgery delivered a single
dose of 20 Gy (specified at the isocenter with a 70% isodose reference curve).
Evaluation of results was performed according to local control, survival,
evolution of performance status, as well as evolution of neurologic symptoms.
RESULTS: No patient had immediate toxicity. One month later, ten patients showed
improvement in their neurologic impairments, and none had progression of the
cerebral lesion according to CT scan evaluation (diminution for seven patients,
and stabilization for five). Local control rate was 58%, and median time to
failure was 4 months. The overall median survival time was 10 months. Three
patients were alive, with good performance status, and six died following
cerebral progression. CONCLUSION: These poor results in terms of local control
are in favor of supplementary whole brain irradiation, except for particular
cases.
PMID- 9755752
TI - [Radiation-induced sarcoma after breast cancer. Apropos of 8 cases and review of
the literature].
AB - PURPOSE: Retrospective analysis of eight new cases of radiation-induced sarcomas
following radiotherapy for breast carcinoma and literature review. PATIENTS AND
METHODS: Eleven patients presenting with radiation-induced sarcoma after
radiotherapy for breast cancer have been treated between 1983 and 1997 at Henri
Mondor University Hospital (France). Eight of these patients respected the
criteria established by Cahan et al. The others had Stewart-Treves Syndrome and
were thus excluded from the analysis. Only one of the eight patients had received
chemotherapy. All of the patients at the time of diagnosis of radiation-induced
sarcoma were free of breast cancer recurrence. Radiation-induced sarcoma appeared
with a latency period of 5 to 18 years (mean: 10.3 years). Patients' ages ranged
from 39 to 88 years (mean: 57.6 years) at the time of diagnosis of sarcoma. Three
sarcomas occurred in the treated breast, two in the chest wall, one in the
preclavicular area and two in the axillary region. There were two angiosarcomas,
three fibrosarcomas, one osteosarcoma, one malignant fibrous histiocytoma (MFH),
and one undifferentiated sarcoma. All patients have received treatment for their
sarcoma: all of them underwent surgery, one patient combined radiotherapy and
chemotherapy, and three patients chemotherapy. RESULTS: Two patients were alive
and free from disease. Six patients died (5-34 months); all six had local and/or
metastatic recurrence. CONCLUSIONS: Radiotherapy can induce malignancies after a
latent period of several years. Radiation-induced sarcomas are associated with
poor overall prognosis. The treatment in most of the cases is late and
ineffective, therefore careful follow-up is needed. There are still many
uncertainties and questions about radiation-induced sarcomas.
PMID- 9755753
TI - [Chondrosarcoma in Ollier's disease. Apropos of 2 cases and review of the
literature].
AB - Ollier's disease is a rate affliction (not more than approximately 100 cases have
been reported over a 30-year period) characterized by bone dysplasia in which
evolution to degenerative neoplasia has been described. Diagnosis of
chondrosarcoma is delicate in these cases. It is a kind of slowly evolving low
grade malignant tumor. Surgery is the primary treatment course, and can lead to
remission. Prognosis, depending on the number and dimension of the lesions, their
localization and metastasis prevention, is usually good, but relapses are
relatively frequent: 25 to 50%. In case of relapse, radiotherapy and chemotherapy
were tested but their efficacy is limited. We report here two clinical cases and
discuss literature data.
PMID- 9755754
TI - [Use of a multileaf collimator for the production of intensity-modulated beams].
AB - In external radiotherapy, the use of intensity modulated fields has been proposed
for tissue and non-homogeneity compensation or for the generation of conformal
dose distributions. Multileaf collimators can be employed dynamically for the
modulation of the X-ray field in two dimensions. Efficient dynamic collimation
became possible due to advances in computer and linear accelerator technology. It
presents a number of advantages over conventional methods such as the use of
compensators. We have developed a program which calculates, from a given
intensity distribution, the motion of the MLC leaves as a function of monitor
units, and we have applied it on a Varian linear accelerator with a 40 pair
multileaf collimator. The analysis of the experimental results demonstrates the
feasibility and the potential of the method.
PMID- 9755756
TI - [Activity of stereotactic radiosurgery and radiotherapy in France. SFRO-1997
survey].
PMID- 9755757
TI - What is computer assisted orthopaedic surgery?
PMID- 9755755
TI - [Cutaneous lymphoma in Tunisia: clinical profile and therapeutic results].
AB - PURPOSE: The aim of this retrospective study was to investigate therapeutic
result of cutaneous lymphoma in Tunisia. PATIENTS AND METHODS: Between January
1969 and June 1994, 100 patients with cutaneous lymphoma were referred either to
Salah Azaiz Institute or the other University Hospitals of Tunisia. Fifty-one
patients had epidermotropic lymphoma and 49 non-epidermotropic lesions. Eighty
seven patients received complete treatment. Puvatherapy and other local
dermatologic treatments were used for early stage mycosis fungoides. Thirty-two
patients benefited from radiotherapy, with curative dose in 28 cases.
Chemotherapy including anthracyclin agents was used for high grade lymphoma.
Thirteen patients had association of radiotherapy and chemotherapy. RESULTS: Five
year survival rates were 50% for patients with epidermotropic lesions and 56% for
patients with non-epidermotropic cutaneous lymphoma. Statistical study has not
identified any significant prognosis factor. CONCLUSION: Radiotherapy and
chemotherapy are both effective. Treatment should depend on stage and histologic
type.
PMID- 9755758
TI - Computer-integrated surgery. Technology and clinical applications. 1996.
PMID- 9755759
TI - Computer assisted orthopaedic surgery. Image guided and robotic assistive
technologies.
AB - Technologies are emerging that will influence the way in which orthopaedic
surgery is planned, simulated, and performed. Recent advances in the fields of
medical imaging, computer vision, and robotics have provided the enabling
technologies to permit computer aided surgery to become an established area which
can address clinical needs. Although these technologies have been applied in
industry for more than 20 years, the field of computer assisted orthopaedic
surgery is still in its infancy. Image guided and surgical navigation systems,
robotic assistive devices, and surgical simulators have begun to emerge from the
laboratory and hold the potential to improve current surgical practice and
patients' outcomes. The goals of these new clinically focused technologies are to
develop interactive, patient specific preoperative planners to optimize the
performance of surgery and the postoperative biologic response, and develop more
precise and less invasive interactive smart tools and sensors to assist in the
accurate and precise performance of surgery. The medical community is beginning
to see the benefit of these enabling technologies which can be realized only
through the collaboration and combined expertise of engineers, roboticists,
computer scientists, and surgeons.
PMID- 9755760
TI - Medical imaging and registration in computer assisted surgery.
AB - Imaging, sensing, and computing technologies that are being introduced to aid in
the planning and execution of surgical procedures are providing orthopaedic
surgeons with a powerful new set of tools for improving clinical accuracy,
reliability, and patient outcomes while reducing costs and operating times.
Current computer assisted surgery systems typically include a measurement process
for collecting patient specific medical data, a decision making process for
generating a surgical plan, a registration process for aligning the surgical plan
to the patient, and an action process for accurately achieving the goals
specified in the plan. Some of the key concepts in computer assisted surgery
applied to orthopaedics with a focus on the basic framework and underlying
technologies is outlined. In addition, technical challenges and future trends in
the field are discussed.
PMID- 9755761
TI - Computer assisted orthopaedic surgery with image based individual templates.
AB - Recent developments in computer assisted surgery offer promising solutions for
the translation of the high accuracy of the preoperative imaging and planning
into precise intraoperative surgery. Broad clinical application is hindered by
high costs, additional time during intervention, problems of intraoperative man
and machine interaction, and the spatially constrained arrangement of additional
equipment within the operating theater. An alternative technique for computerized
tomographic image based preoperative three-dimensional planning and precise
surgery on bone structures using individual templates has been developed. For the
preoperative customization of these mechanical tool guides, a desktop computer
controlled milling device is used as a three-dimensional printer to mold the
shape of small reference areas of the bone surface automatically into the body of
the template. Thus, the planned position and orientation of the tool guide in
spatial relation to bone is stored in a structural way and can be reproduced
intraoperatively by adjusting the position of the customized contact faces of the
template until the location of exact fit to the bone is found. No additional
computerized equipment or time is needed during surgery. The feasibility of this
approach has been shown in spine, hip, and knee surgery, and it has been applied
clinically for pelvic repositioning osteotomies in acetabular dysplasia therapy.
PMID- 9755762
TI - Pedicle screw placement using image guided techniques.
AB - Clinical evaluation of a computer assisted spine surgical system is presented.
Eighty pedicle screws were inserted using computer assisted technology in
thoracic and lumbar vertebrae for treatment of different types of disorders
including fractures, spondylolisthesis, and scoliosis. Fifty-two patients with
severe fractures, spondylolisthesis, or pseudoarthrosis of T10 to L5 were treated
using a computer assisted technique on 1/2 the patients and performing the screw
insertion manually for the other 1/2. At the same time, 28 pedicle screws were
inserted in T12 to L4 vertebrae for scoliosis with the help of the computer
assisted technique. Surgery was followed in all cases (66 vertebrae; 132 pedicle
screws) by postoperative radiographs and computed tomographic examination, on
which measurements of screw position relative to pedicle position could be done.
For fractures, spondylolisthesis, or pseudarthrosis, comparison between the two
groups showed that four screws in 52 (8%) vertebrae had incorrect placement with
computer assisted technique whereas 22 screws in 52 (42%) vertebrae had incorrect
placement with manual insertion. In patients with scoliosis, four screws in 28
(14%) vertebrae had incorrect placement. In all of the patients (132 pedicle
screws) there were no neurologic complications. These results show that a
computer assisted technique is much more accurate and safe than manual insertion.
PMID- 9755763
TI - Computer assisted knee replacement.
AB - Accurate alignment of knee implants is essential for the success of total knee
replacement. Although mechanical alignment guides have been designed to improve
alignment accuracy, there are several fundamental limitations of this technology
that will inhibit additional improvements. Various computer assisted techniques
have been developed to examine the potential to install knee implants more
accurately and consistently than can be done with mechanical guides. For example,
computer integrated instrumentation incorporates highly accurate measurement
devices to locate joint centers, track surgical tools, and align prosthetic
components. Image guided knee replacement provides a three-dimensional
preoperative plan that guides the placement of the cutting blocks and prosthetic
components. Robot assisted knee replacement allows one to machine bones
accurately without the use of standard cutting blocks. The rationale for the
development of computer assisted knee replacement systems is presented, the
operation of several different systems is described, the advantages and
disadvantages of different approaches are discussed, and areas for future
research are suggested.
PMID- 9755764
TI - Computer assisted reconstruction of the anterior cruciate ligament.
AB - Reconstruction of the anterior cruciate ligament is a delicate task for which
many different techniques have been proposed. A system consisting of a computer
and a three-dimensional optical sensor is proposed to help the surgeon control
the placement of a graft. This system can be used to minimize anisometry of the
graft and avoid notch impingement. The same system, which had been validated by
previous testing on 20 fresh human anatomic specimen knees, was tested on 23
patients who had an anterior cruciate ligament injury. Tunnel placement was
performed using the standard technique of Morgan et al and was measured with the
computer based system. It was found that all cases had different configurations
of tibial and femoral placement. The computer based anisometry measurements
ranged from 1.9 mm to 8.8 mm in the anterior part of the graft, and from 1 mm to
13 mm in the centers of the tunnels. Using the computer retrospectively, it was
possible to find configurations of the graft in all cases that avoid notch
impingement, with anisometry values ranging from 1.3 mm to 3.7 mm. This study
shows that a computer based system can be a useful tool for routine anterior
cruciate ligament reconstruction and can be useful for research purposes.
PMID- 9755765
TI - Computer assistance in arthroscopic anterior cruciate ligament reconstruction.
AB - Accurate placement of the graft is considered one of the most important factors
in anterior cruciate ligament surgery. However, reconstruction with contemporary
guiding systems still can result in unacceptable graft placement variability. To
improve the reproducibility of graft placement, intraoperative visual feedback
was added to the arthroscopic technique. First, fluoroscopic visualization was
added to evaluate guidewire placement before tunnel drilling. Second, computer
graphic overlays were added to the fluoroscopic view. Three groups of patients
were treated: 29 patients with arthroscopy, 53 patients with fluoroscopy added,
and 50 patients with computer overlays added. Graft placement variability was
reduced significantly with fluoroscopic visualization. Computer overlays resulted
in additional significant reductions in graft placement variability. Simple
visual enhancements seem to be useful in improving the accuracy of arthroscopic
anterior cruciate ligament reconstruction.
PMID- 9755766
TI - Computer assisted measurement of cup placement in total hip replacement.
AB - The introduction of image guided systems in total hip replacement surgery
provides the ability to plan precisely the alignment of the acetabular cup before
surgery, and to perform the surgery according to the preoperative plan.
Preoperative planners (interactive computer programs for surgical planning) based
on three-dimensional medical images allow planning of optimal placement of
implant components based on simulated implant performance. Exact measurement of
the cup position during surgery allows precise placement of the cup and accurate
measurement of the final position of the cup relative to the pelvis. This
measurement is used to evaluate the radiographic techniques for postoperative
measurement of cup alignment. Malposition of the acetabular component increases
the occurrence of impingement, reduces the safe range of motion, and increases
the risk of dislocation and wear. Dislocation of the implant after total hip
replacement remains a significant clinical problem. Not fully understanding the
interaction between pelvic orientation and final acetabular cup alignment may be
one of the main contributing factors in the continued significant incidence of
dislocations after total hip replacement. In this study an attempt was made to
link the preoperative planning, intraoperative placement, and postoperative
measurement of cup placement in total hip replacement using computer assisted
techniques.
PMID- 9755767
TI - Primary and revision total hip replacement using the Robodoc system.
AB - The ROBODOC system was designed to address potential human errors in performing
cementless total hip replacement. The system consists of a preoperative planning
computer workstation (called ORTHODOC) and a five-axis robotic arm with a high
speed milling device as an end effector. The combined experience of the United
States Food and Drug Administration multicenter trial and the German postmarket
use of the system are reported. The United States study is controlled and
randomized with 136 hip replacements performed at three centers (65 ROBODOC and
62 control). Followup was 1 year on 127 hip replacements and 2 years on 93 hip
replacements. No differences were found in the Harris hip scores or the Short
Form Health Survey outcomes questionnaire. Length of stay also was not different,
but the surgical time and blood loss were greater in the ROBODOC group. This was
attributed to a learning curve at each center. Radiographs were evaluated by an
independent bone radiologist and showed statistically better fit and positioning
of the femoral component in the ROBODOC group. Complications were not different,
except for three cases of intraoperative femoral fracture in the control group
and none in the ROBODOC group. The German study reports on 858 patients, 42 with
bilateral hip replacements and this includes 30 revision cases for a total of 900
hip replacements. The Harris hip score rose from 43.7 to 91.5. In these cases the
surgical time declined quickly from 240 minutes for the first case to 90 minutes.
No intraoperative femoral fractures occurred in 900 cases. Other complications
were comparable with total hip replacements performed using conventional
techniques. The ROBODOC system is thought to be safe and effective in producing
radiographically superior implant fit and positioning while eliminating femoral
fractures.
PMID- 9755768
TI - Computer assistance for pelvic osteotomies.
AB - To assist surgeons performing pelvic osteotomies for the treatment of dysplastic
hips, an image guided freehand navigation system has been developed. Preoperative
computed tomographic scan images are presented in various ways to the surgeon
together with real time display of the instruments and surgical action on the
computer screen. The system supports the preoperative plan and provides optimized
control of surgical action. The main focus of the image guidance has been placed
on the execution of the different required cuts and the reorientation of the
acetabular fragment. Special attention also has been given to the development of
a sophisticated surgeon-machine interface. Fourteen surgeries have been performed
with image guidance so far. The visualization aids provided by the system are
able to help reduce potential risk and thus increase safety and accuracy for this
difficult class of surgical interventions.
PMID- 9755769
TI - Percutaneous iliosacral screw placement using image guided techniques.
AB - A computer assisted technique of iliosacral screw placement that is applicable to
unstable pelvic ring fractures is proposed. The goals are to operate
noninvasively with a percutaneous procedure to decrease the complications of
surgical exposure and to provide greater accuracy in locating the close
neurovascular structures. Preoperative computed tomographic images of the pelvis
are provided and a computed tomography three-dimensional model is built. In this
model, the optimal trajectories for the drilling are planned. An ultrasound based
registration is performed intraoperatively. This registration is the most
original part of this work. After performing the passive drilling guidance step,
the surgeon places the screws. The accuracy of the ultrasound based registration
is checked by comparison with a standard surface based registration at the end of
the test experiment. Each screw position is verified by a computed tomographic
examination. Four human anatomic specimen pelves were tested with three screw
insertions for each pelvis (12 screws). All of the screws were considered to be
placed correctly. The method is safe and encourages the start of clinical
application.
PMID- 9755770
TI - Augmented reality and its future in orthopaedics.
AB - Augmented reality is a display technique that combines supplemental information
with the real world environment. Augmented reality systems are on the verge of
being used everyday in medical training, preoperative planning, preoperative and
intraoperative data visualization, and intraoperative tool guidance. The basic
technologies of augmented reality are discussed, augmented reality systems
currently being used in the medical domain are examined, and some future uses of
these systems in orthopaedic applications are explored.
PMID- 9755771
TI - Electromyographic analysis of shoulder joint function of the biceps brachii
muscle during isometric contraction.
AB - Surface electromyography was performed for both heads of the biceps brachii in 11
healthy men while the muscles were under 30% maximum isometric shoulder flexion
and abduction. Elbow related biceps activity was minimized by using a brace
locked in neutral forearm rotation. Electromyographic activity was normalized as
a percentage of maximal muscle contraction during 24 shoulder motions.
Electromyographic activity was detected in all motions examined, suggesting that
the biceps muscle acts as a flexor and an abductor of the shoulder. Both heads of
the biceps muscle had higher activities during external rotation than during
internal rotation for most motions. Activities of both heads increased with arm
elevation, but showed little dependence on elbow position. The long head was
still active during internal rotation of the shoulder. These findings also
suggest that the biceps muscle is a flexor and an abductor of the shoulder, and
that the long head can act as a humeral head stabilizer in superior and anterior
directions. Muscle fatigue of the biceps and the deltoid muscle also was
determined at 30% of maximum isometric flexion. All muscles had significantly
decreased mean power frequency and turns count, and increased amplitude and
integrated electromyography. The rate of decrease in mean power frequency was
larger for the biceps than for the deltoid muscle, and the rate of increase in
amplitude was larger for the long head of the biceps than for the short head or
for the deltoid muscle. These findings suggest that the long head of the biceps
must increase its mechanical output to keep the arm in elevation to a greater
extent than do the short head and the deltoid muscle. This may be one of the
causes of tendinitis or rupture of the long head.
PMID- 9755772
TI - Shoulder joint kinetics during the push phase of wheelchair propulsion.
AB - The purpose of this investigation was to quantify the forces and moments at the
shoulder joint during free, level wheelchair propulsion and to document changes
imposed by increased speed, inclined terrain, and 15 minutes of continuous
propulsion. Data were collected using a six-camera VICON motion analysis system,
a strain gauge instrumented wheel, and a wheelchair ergometer. Seventeen men with
low level paraplegia participated in this study. Shoulder joint forces and
moments were calculated using a three-dimensional model applying the inverse
dynamics approach. During free propulsion, peak shoulder joint forces were in the
posterior (46 N) and superior directions (14 N), producing a peak resultant force
of 51 N at an angle of 185 degrees (180 degrees = posterior). Peak shoulder joint
moments were greatest in extension (14 Newton-meters [Nm]), followed by abduction
(10 Nm), and internal rotation (6 Nm). With fast and inclined propulsion, peak
vertical force increased by greater than 360%, and the increase in posterior
force and shoulder moments ranged from 107% to 167%. At the end of 15 minutes of
continuous free propulsion, there were no significant changes compared with short
duration free propulsion. The increased joint loads documented during fast and
inclined propulsion could lead to compression of subacromial structures against
the overlying acromion.
PMID- 9755773
TI - The triceps preserving approach to total elbow arthroplasty.
AB - Elbow arthroplasty most commonly is performed through a posterior approach by
detaching or reflecting the triceps off the olecranon. Surgical approaches to the
elbow joint that dissociate the triceps from the olecranon have distinct
disadvantages. Triceps avulsion, triceps weakness, and wound healing problems
have been reported. Such complications necessitate more surgery and predispose
the joint to an infection. To avoid these complications a modified posterior
approach to the elbow joint that preserves the triceps muscle insertion on the
olecranon was used in 10 consecutive elbow arthroplasties. This method provides
adequate exposure, allows early rehabilitation, and avoids triceps weakness.
PMID- 9755774
TI - Right versus left symmetry of ulnar variance. A radiographic assessment.
AB - One hundred skeletally mature healthy volunteers underwent standardized bilateral
posteroanterior radiographs in unloaded (static) and loaded (dynamic) conditions
to determine the symmetry of ulnar variance. The mean age was 32 +/- 9 years
(range, 19-61 years), with 58 women and 42 men. Ulnar variance was measured to
the closest 0.5 mm using the method of perpendiculars. Three separate
measurements were made of each radiograph in a blinded fashion by the same
investigator. An intraobserver standard deviation of 0.21 was used to calculate a
95% tolerance interval of 0.7 mm (rounded up to 1 mm) as a measure of
significance. The average static ulnar variance was -0.13 +/- 1.5 mm on the left
and -0.29 +/- 1.6 mm on the right. The average dynamic ulnar variance was 0.93 +/
1.5 mm on the left and 0.82 +/- 1.5 mm on the right. When compared individually,
there was a greater than or equal to 1 mm side to side difference in 37% of
volunteers under static and 38% under dynamic conditions. There were no
significant correlations between ulnar variance measurements and patient age,
gender, race, or handedness. Use of the normal wrist radiograph as a baseline for
static radial length measurements is valid in only 63% of cases.
PMID- 9755775
TI - Radiographic predictors of outcome of core decompression for hips with
osteonecrosis stage III.
AB - Various investigators have studied the prognostic influence of various
demographic, laboratory, and radiographic parameters on outcome for different
treatment methods for osteonecrosis of the femoral head. A cross sectional study
was done of 52 patients (68 hips) who had a core decompression for Ficat and
Arlet Stage III osteonecrosis of the femoral head. The purpose of this study was
to evaluate the prognostic significance of various radiographic factors for risk
of disease progression after treatment with core decompression. Radiographic
parameters included Steinberg stages (III or IV), Ohzono stage (central or
lateral location), amount of head depression, extent of crescent sign arc, and
extent of lesion by Kerboul combined necrotic angle measurements. Patient outcome
assessment was at a followup mean of 12 years (range, 4-18 years) after core
decompression. Overall, 20 of the 68 hips (29%) had satisfactory outcomes. Of the
44 hips with Steinberg Stage III disease, 18 (41%) underwent total hip
arthroplasty. In comparison, in the Steinberg Stage IV hips, 22 of 24 hips (92%)
underwent arthroplasty. Ohzono Stage B lesions had 50% survival (eight of 16
hips) compared with 23% survival (12 of 52 hips) for Ohzono Stage C. Hips with
combined necrotic angles greater than 250 degrees had 16% survival (seven of 45)
which can be compared with 57% survival (13 of 23) for hips with angles less than
250 degrees. The best multiple regression model for a satisfactory outcome was a
Steinberg Stage III hip (no head depression), a central lesion (Ohzono Stage B),
and a small lesion (< 250 degrees combined necrotic angle). With this
combination, there were 89% satisfactory outcomes (8 of 9 hips). Conversely, the
best generalized linear model for unsatisfactory outcomes (0 hips surviving of
14) was Steinberg Stage IV disease (head depression), lateral location (Ohzono
Stage C lesion), and a large extent of the lesion (> 250 degrees combined
necrotic angle).
PMID- 9755776
TI - Patella height after high tibial osteotomy with internal fixation and early
motion.
AB - The purpose of this study was to compare the incidence of patella infera in
patients after high tibial osteotomy treated with either postoperative
immobilization or internal fixation and early range of motion. A retrospective
review of 98 patients with high tibial osteotomy was done at the authors'
institution. Thirty-three patients who had secondary procedures such as
concomitant ligamentous reconstruction with early motion were excluded.
Therefore, 69 knees in 65 patients remained in the study cohort. Group A
consisted of 32 patients (34 knees) treated with postoperative immobilization,
whereas Group B included 33 patients (35 knees) treated with internal fixation
and early motion. The preoperative and postoperative Insall-Salvati index,
Blackburne-Peel index, and angular alignment were determined for each group.
Between Groups A and B, the differences in the Insall-Salvati index and the
Blackburne-Peel index were statistically significant, although the difference in
angular correction was not significant. With rigid fixation and early motion the
Insall-Salvati index showed that there was less postoperative shortening of the
patellar tendon. The relationship of the patella to the remainder of the knee was
affected less adversely as evidenced by the Blackburne-Peel index. High tibial
osteotomy with internal fixation and early range of motion should result in a
better knee and ease the subsequent performance of a total knee arthroplasty.
PMID- 9755777
TI - Pseudoaneurysm after high tibial osteotomy and limb lengthening.
AB - A case of a young man with anterior tibial artery rupture and pseudoaneurysm
formation that occurred during lengthening of a scarred limb is presented. Leg
length discrepancy occurred because of previous distal femoral and proximal
tibial fractures. Two corrective operations were performed 11 and 2 years earlier
at another hospital. As limb deformity persisted, distal femoral and proximal
tibial osteotomies combined with limb lengthening were performed. The aim was to
achieve 120 mm (70 mm femoral, 50 mm tibial) lengthening. The operative and early
postoperative course was uneventful. Twenty-six days after surgery (when femoral
and tibial lengthening was 13.5 mm and 5.5 mm, respectively), blood began oozing
from the operative scar during limb distraction. At 70 days after surgery (when
femoral and tibia lengthening was 41.5 mm and 14 mm, respectively), a rupture and
pseudoaneurysm of the anterior tibial artery became apparent. Documentation of a
normal pulses in the foot after surgery, the late presentation of pseudoaneurysm,
and the initiation of bleeding by limb distraction indicate that limb lengthening
either aggravated an unrecognized arterial injury or precipitated de novo rupture
of the anterior tibial artery scarred from previous trauma. The pseudoaneurysm
was treated successfully by transarterial embolization.
PMID- 9755778
TI - Relationship between gait and clinical results after high tibial osteotomy.
AB - Thirty-two patients with primary osteoarthritis of the medial compartment of the
knee were studied prospectively to assess the relationship between clinical
results, limb alignment, and adduction moment of the knee. Clinical and
radiographic examination and gait analyses were performed preoperatively and
repeated at 6 months and at 1, 3, and 6 years after high tibial osteotomy. The
preoperative peak adduction moment was high in 25 patients and low in seven. In
both groups, the adduction moment of the knee decreased at 6 months after surgery
but increased after that period. Alignment of the affected knee in both groups
remained valgus after surgery (average femorotibial angle, 167 degrees-169
degrees). Clinical outcome in both groups improved after surgery and remained
unchanged after 1 year. The peak adduction moment of the knee for the whole group
significantly correlated with alignment and foot angle before and 6 years after
surgery but did not correlate with stride length and walking velocity. In
addition, only alignment was associated significantly with clinical results at 6
years. These results suggest that the preoperative peak adduction moment of the
knee does not correlate with clinical or radiographic outcomes of high tibial
osteotomy, provided sufficient valgus alignment is achieved at surgery.
PMID- 9755779
TI - Postlaminectomy and postirradiation kyphosis in children and adolescents.
AB - This is a retrospective review of 12 patients treated for severe postlaminectomy
and postirradiation kyphosis by one surgeon from 1977 to 1994. The average age of
the patients was 15 years with a range from 2 to 35 years. The duration of
followup ranged from 24 months to 156 months with an average of 65 months. All
patients had undergone multilevel laminectomies or irradiation of the thoracic or
lumbar spine for an intraspinal lesion or trauma. The average preoperative
kyphosis was 84 degrees and this was reduced to an average of 39 degrees after
surgery. There were no pseudarthroses and there was an average loss of correction
of 5 degrees. There were no complaints of back pain. Moderately severe but
flexible kyphoses were treated in three patients by posterior instrumentation and
spinal fusion. The other nine patients had combined anterior release or
decompression and fusion combined with posterior instrumentation and spinal
fusion. Bracing failed to halt the progressive kyphosis in those patients for
whom it had been attempted. The only major complications in this series were two
wound infections in patients previously treated with irradiation.
PMID- 9755780
TI - The evolution of femoral shaft plating technique.
AB - There has been an evolution in the AO/Association for the Study of Internal
Fixation plating technique during the past 3 decades that includes the use of
longer plates and fewer plate screws, fewer lag screws outside the plate, fewer
unicortical screws at the plate periphery, and greater use of the 95 degrees
blade plate to achieve balanced fixation of proximal and distal shaft fractures.
These changes reflect an evolving technique of plate osteosynthesis that
emphasizes indirect reduction techniques, biologic internal fixation, and
improved biomechanics. Outcome data suggest that there has been an improvement
with time that is reflected by shorter time to union, a decrease in the frequency
of implant failures, delayed unions, nonunions, malunions, number of
reoperations, and in overall rate of failure. The best predictor of success was
the length of plate by logistic regression analysis. With the evolution of
plating techniques and a greater emphasis on biology of fracture healing, the
incidence of complications and failures has decreased after femoral shaft
plating. Plate osteosynthesis of the femoral shaft is particularly advantageous
in many situations and can be quite successful (87% success rate in Group III).
PMID- 9755781
TI - Effect of methotrexate on distraction osteogenesis.
AB - To assess the potential of using distraction osteogenesis to reconstruct bone
deficient limbs after limb salvage for musculoskeletal sarcomas, the authors
examined the effect of methotrexate on distraction osteogenesis in a rabbit
tibial lengthening model. Eighteen rabbits underwent tibial corticotomy and
application of a ring external fixator. Rabbits were assigned randomly to one of
two groups in which either methotrexate (n = 12) or placebo (n = 6) was
administered during a 21-day distraction period. Serum methotrexate levels and
complete blood cell counts were monitored during distraction, and radiographs of
the tibia were obtained weekly. Half of the animals from each group were
sacrificed at the end of distraction, and the remaining animals were sacrificed
after 6 weeks of neutral fixation when bone normally bridges the gap. Using
methotrexate at serum concentrations similar to those used clinically for the
treatment of human osteosarcomas, the authors were unable to show significant
radiographic, histologic, or chemical differences in the effect of this
antineoplastic drug on distraction osteogenesis in the rabbit model.
PMID- 9755782
TI - Periosteal augmentation of the acetabulum.
AB - The periosteum in children and especially infants has significant osteogenic
potential. To determine the efficacy of periosteal flaps to assist in improving
acetabular coverage in children with acetabular dysplasia, a series of
experiments were designed using young rabbits. Three groups of five rabbits each
had periosteal flaps fashioned and brought down from the anterolateral aspect of
the innominate bone superior to the acetabulum and sutured to the capsule of the
hip. The study was designed to examine the effects of the periosteal cambium
layer in the formation of new bone to augment the acetabulum and to determine the
effects of a periosteal flap plus cancellous bone graft. A control group of five
rabbits underwent a sham operation of an open arthrotomy of the hip. Radiographic
and histologic examination at 12 weeks revealed augmentation of the acetabulum
with periosteal flaps that resulted in an average improvement of the acetabular
index of 3.5 degrees and 6.6 degrees, without and with bone graft, respectively.
New bone formation from the rim of the acetabulum averaged 3.9 mm with periosteal
flaps alone and 4.6 mm with bone graft added. Periosteal augmentation of the
acetabulum in conjunction with established procedures for augmenting acetabular
coverage would appear to be a useful procedure for improving coverage of the
femoral head in children with acetabular dysplasia.
PMID- 9755783
TI - Cartilage changes caused by a coronal surface stepoff in a rabbit model.
AB - Coronal stepoffs of 0.5 mm (equal to the cartilage height) were created on the
medial femoral condyles of adult, skeletally mature rabbits as a model for
articular surface incongruity. After 3, 6, 12, and 24 weeks, tissue was analyzed
histologically using hematoxylin and eosin and Safranin O staining,
autoradiographs were made of the femoral condyles, and immunohistologic analysis
was done for 3-B-3(-) and 7-D-4 chondroitin sulfate epitopes. An overlapping flap
from the high toward the low side and an increase of the cartilage height on the
low side of the defect were observed as permanent features of adaptation
throughout the entire followup. Significant degeneration was not seen around the
lesion or in the tibial cartilage opposing a stepoff defect. Autoradiography
showed a three-phase response to the lesion: an early increase in radiolabeled
sulfate (35SO4) uptake, a sharp decline of 35SO4 uptake, and finally a late
recovery of the autoradiographic signal indicating partial recovery of
proteoglycan synthetic activity. After an early increase, immunohistologic
analysis for 3-B-3(-) showed a subsiding tendency by 24 weeks, and the staining
with 7-D-4 remained elevated uniformly in the vicinity of the lesion. A rabbit
femoral stepoff defect with an offset of 0.5 mm may remodel and not lead to
degeneration within the first 6 months after injury in a stable joint.
PMID- 9755784
TI - Role of medical capsule and transverse metatarsal ligament in hallux valgus
deformity.
AB - The role of the medial capsule and transverse metatarsal ligament in hallux
valgus deformity including stability of the first metatarsophalangeal and
adjacent joints was investigated in vitro. The three-dimensional positions of the
proximal phalanx, first metatarsal, and second metatarsal before and after
sectioning the medial capsule and metatarsal ligament were measured using a
magnetic tracking system. Valgus deformity of the hallux increased with medial
capsule sectioning an average of 22.3 degrees +/- 6 degrees. Valgus deformity of
the hallux increased with medial capsule and metatarsal ligament sectioning an
average of 27.4 degrees +/- 9.1 degrees. Valgus deformity of the hallux did not
change significantly after sectioning the metatarsal ligament only. No
significant changes were found in varus and eversion of the first metatarsal, in
valgus of the second metatarsal, in the distance between first and second
metatarsal heads after sectioning the medial capsule, or in the metatarsal
ligament. This study shows the importance of the medial capsule in hallux valgus
deformity. The transverse ligament did not contribute substantially to cause the
deformity.
PMID- 9755785
TI - Kappa Delta Award. Low back pain and whole body vibration.
AB - The investigators describe their multifaceted approach to the study of the
relationship between whole body vibration and low back pain. The epidemiologic
study was a two center study of drivers and sedentary workers in the United
States and Sweden. The vibration exposure was measured in the vehicles. It was
found that the career vibration exposure was related to low back, neck, and
shoulder pain. However, disability was related to job satisfaction. In vivo
experiments, using percutaneous pin mounted accelerometers have shown that the
natural frequency is at 4.5 Hz. The frequency response is affected by posture,
seating, and seat back inclination. The response appears to be determined largely
by the rocking of the pelvis. Electromyographic studies have shown that muscle
fatigue occurs under whole body vibration. After whole body vibration exposure
the muscle response to a sudden load has greater latency. Vehicle driving may be
a reason for low back pain or herniated nucleus pulposus. Prolonged seating
exposure, coupled with the whole body vibration, should be reduced for those
recovering from these problems. Vibration attenuating seats and correct ergonomic
layout of the cabs may reduce the risks of recurrence.
PMID- 9755786
TI - Unusual soft tissue mass in a 43-year-old man.
PMID- 9755787
TI - Possibility of a late infection of a joint implant because of dental procedures.
PMID- 9755788
TI - A personal history of stapedectomy.
AB - Aristotle has said the essential ingredient of tragedy is first hubris. Fame
leads to the hubris that offends the gods, who send great punishment. This is so
true in the history of stapedectomy. The three distinct eras of surgery for
otosclerosis teach us a lot about what happens in science and in life. The first
stapes era began in Europe, ahead of its time, and in those halcyon days before
the turn of the century, the Belle Epoch, proceeded, uncorrected to its tragic
extreme, and then was stopped suddenly, quite rightly, by the establishment. The
fenestration era proceeded to an extreme, when its technical master Julius
Lempert would allow no criticism or improvement in "his" one-stage endaural
technique, however good, nor would he accept the new mobilization and
stapedectomy operations, and he and it ended badly. The fact that Jenkins and
Holmgren would make an opening in the lateral semicircular canal and then close
it in the epitympanum, not open to the ear canal, to expect to improve hearing is
amazing. Until Sourdille went to Stockholm and saw one closed fenestration
operation performed by Holmgren and devised his "open to the ear canal
technique," the closed fenestration operation was not reasonable. Then Sourdille
came to New York City, and Lempert heard him speak and read and reread his
publication and greatly improved on his operation. It was Lempert's one-stage
endaural open operation that gave the fenestration operation the worldwide
acceptance it gained. The second stapedectomy era began before the fenestration
era ended with the accidental and originally unrecognized mobilization of the
stapes by Rosen and my resurrection of stapedectomy. I realized in reading the
literature of the past that stapedectomy was not necessarily fatal to the ear or
the patient as was generally believed, and what was needed was to seal the oval
window with a living elastic membrane and reconstruct the sound-conducting
mechanism of the middle ear with a biocompatible implant prosthesis to make it
successful. But for me, in 1955-1956, the "Zeitgeist" was finally right. I
realized the stapes could be removed and covered the oval window with a vein
graft, and Harry Treace made me a biocompatible implant prosthesis out of the
newly discovered Teflon. For a new technology to be accepted, it must be much
better than what it replaces, and stapedectomy was much better than fenestration.
In the new microsurgical era of otology that began, improvements in the
stapedectomy operation came from everywhere and were readily accepted.
Stapedectomy has now become so successful, like many treatments in medicine, the
problem has now largely disappeared. If the measles virus is the cause of the
growth of the otosclerotic focus, as it seems to be, then vaccination against
measles eventually will eliminate the hearing loss of otosclerosis completely.
What the history of stapedectomy reveals is the truth of the quotation from
Ecclesiastes, "There is nothing new under the sun." Progress is only made when
the Zeitgeist is right, by someone who puts together the truths of the past with
the new discoveries of the present.
PMID- 9755789
TI - Lymphocytes: attackers and targets of the same oncogenic viruses, depending on
their immunogenic strength.
PMID- 9755790
TI - Possible retroviral etiology of human breast cancer.
AB - Since the discovery in the early 1980s that retroviruses are pathogenic to man,
the mouse mammary tumor viruses (MMTVs) received great attention. Studies of
MMTVs allowed considerable insights into the mechanisms at work in breast
tumorigenesis. MMTVs are essentially insertional mutagenes. Numerous oncogenes
have been found altered by MMTVs, either specific for MMTVs or not. However,
despite considerable attempts, the involvement of MMTVs in human breast cancer
remains questionable. Yet a retroviral etiology of human breast cancer cannot be
discarded since retroviruses are good candidates to play a role in diseases
which, like human breast cancer, appear either as sporadic or inherited. Due to
their replication cycle, retroviruses can be propagated not only as infectious
agents able to freely infect host cells, but also as cellular genes which can be
passed on to progeny. It is suggested here to search for a new human retrovirus
in sporadic breast cancer, using the techniques which led to the isolation of
human T-cell leukemia virus-1 (HTLV-1). Indeed, finding an infectious retrovirus
in sporadic cases could lead, via the c-DNA probes derived from it, to testing
the hypothesis that the inherited form of human breast cancer may result from the
action of retroviral genes integrated in the germ line.
PMID- 9755791
TI - Epstein-Barr virus in the pathogenesis of Hodgkin's disease.
AB - Epidemiologic and clinico-pathologic features of Hodgkin's disease suggest that
an infectious agent may be involved in the pathogenesis of this puzzling
disorder. Recently accumulated data provide direct evidence supporting a causal
role of Epstein-Barr virus in a significant proportion of cases. In addition to
allowing a better understanding of the complex pathogenesis of Hodgkin's disease,
these virological advances, briefly reviewed herein, also constitute an important
basis for the development of new therapeutic strategies.
PMID- 9755792
TI - Human papillomavirus infections in skin cancers.
AB - Non-melanoma skin cancer (NMSC) is the most frequent cancer among Caucasians
worldwide. The lesions occur preferentially on sun-exposed sites of the body. The
role of human papillomavirus (HPV) in the etiology of carcinoma of the genital
tract is well established. Epidermodysplasia verruciformis (EV) has been regarded
as a model for NMSC developing on sun-exposed sites. Infection with a specific
group of HPV types has been associated with the benign and malignant lesions
occurring in these patients. Recent studies using improved detection methods, as
well as re-examining material used in previously published studies, reported the
presence of HPV DNA in NMSC from immunocompetent patients, as well as more than
90% of NMSC occurring in organ transplant recipients. Five HPV types were
identified as the most prevalent in these tumors, i.e., HPV 20, HPV 23, HPV 38
and two newly identified HPV types, DL40 and DL267. These and other HPV types
were also demonstrated in normal skin biopsies (35%) and a small number of
melanomas. The frequent presence of more than one HPV type within a lesion was
noticeable, with at least one type belonging to the EV-associated HPV types.
Present data indicate that the primary infection with the majority of, if not
all, HPV types, apparently occurs early in life, after which it remains latent.
Prolonged ultraviolet (UV) radiation is needed either to activate viral gene
functions, and/or to inactivate cellular genes responsible for controlled cell
growth. Further studies are clearly needed to determine the molecular mechanisms
by which these HPV infections in combination with UV-radiation may contribute to
this carcinogenic process.
PMID- 9755793
TI - Hepatitis B viruses and cancerogenesis.
AB - Hepatitis B virus (HBV) is a small, enveloped DNA virus which primarily infects
liver cells and causes acute and persistent liver disease. Chronic HBV infection,
frequently associated with cirrhosis and eventually hepatocellular carcinoma
(HCC), represents a major health problem in the world. HBV is the prototype
member of the hepadnavirus family, which includes several related mammalian
viruses also implicated in liver carcinogenesis in the host. Although
epidemiological evidence has clearly linked HBV infection with HCC development,
the precise role of the virus and the molecular mechanisms of liver cell
transformation remain elusive. Here we discuss potential oncogenic strategies of
HBV, ranging from indirect mechanisms related to chronic necroinflammatory
disease and to the effects of viral gene products on cell proliferation and
apoptosis, to direct insertional activation of cellular (onco)genes. Presently,
vaccination of high risk populations represents a major way to prevent the
development of HBV-related liver cancer.
PMID- 9755794
TI - Latest developments in radiology.
PMID- 9755795
TI - Contrast agents in magnetic resonance imaging of the liver: present and future.
AB - New contrast agents are being developed by drug companies to better image the
liver magnetic resonance imaging (MRI). They can be divided into hepatobiliary
agents (Gd-EOB-DTPA, Gd-BOPTA, Mangafodipir) and nanoparticulate agents directed
to the reticulo-endothelial system (ferumoxides, SHU 555A). After intravenous
injection, all these agents concentrate in the liver and induce profound signal
changes. Particulate agents induce predominantly a darkening of the liver
parenchyma, while hepatobiliary agents induce a brightening. In both cases, liver
lesion conspicuity is enhanced, leading to a better visualization of the lesion.
After a description of the principal pharmacokinetic characteristics of the
compounds, this review paper summarizes the utility of the agents in the
detection and characterization of focal liver diseases.
PMID- 9755797
TI - Teleradiology.
AB - According to the American College of Radiology, teleradiology is an electronic
transmission of radiological images from one location to another for the purposes
of interpretation or consultation. This article provides a historical perspective
and discusses both solved and unsolved problems concerning the different elements
of a teleradiology system (image acquisition, image transmission, image display,
image compression). It concludes that teleradiology will in the future be a part
of picture archiving and communication systems (PACS). Technical problems have
for the most part been solved, with the exception of quality of gray-scale
monitors. The characteristics of such a system depends on its goals.
PMID- 9755796
TI - Computed radiography.
AB - In several medical centers computed radiography has almost completely replaced
the use of conventional screen-film systems for general radiography. The aim of
this paper is to explain the basic principles of the four most frequently
numerical detectors used in the world, with emphasis on the phosphor plates,
which are the most frequently used both in hospitals and by practitioners. The
other two systems are based on a receptor with selenium. The fourth uses charged
coupled device (CCD) detectors. The most important principles of digital
processing are then described with concentration on unsharp mask filtering. In
the future computed radiography will replace standard radiology and will create a
system in medicine using the power of computers to archive--with more efficiency
and less space--patient medical data. The transmission of data to workstations
and the processing of this data is the topic of a new field in medicine.
PMID- 9755798
TI - Fat suppression techniques in MRI: an update.
AB - Due to short relaxation times, fat has a high signal on magnetic resonance images
(MRI). This high signal, easily recognized on MRI, may be useful to characterize
a lesion. However, small amounts of lipids are more difficult to detect on
conventional MRI. In addition, the high signal due to fat may be responsible for
artifacts such as ghosting and chemical shift. Lastly, a contrast enhancing tumor
may be hidden by the surrounding fat. These problems have prompted development of
fat suppression techniques in MRI. Fat may be suppressed on the basis of its
difference in resonance frequency with water by means of frequency selective
pulses or phase contrast techniques, or on the basis of its short T1 relaxation
time by means of inversion recovery sequences. Lastly, hybrid techniques
combining several of these fat suppression techniques are also possible. The aim
of this paper is to review the basic principles of all these fat suppression
techniques and to exemplify their clinical use.
PMID- 9755799
TI - Materials and biomaterials for interventional radiology.
AB - Devices used in interventional radiology have significantly developed in the past
few years. In order to understand the trends of this development, we analyzed how
new interventional devices are progressively incorporating materials having
original physical properties, and how developers are today progressively turning
towards biomaterials, with respect to the new regulatory environment, and the
requirements of biocompatibility.
PMID- 9755800
TI - Novel implications of the potential role of selenium on antioxidant status in
streptozotocin-induced diabetic mice.
AB - Levels of blood glucose, lipid peroxidation, glutathione (GSH), glutathione
peroxidase (GPx), glutathione S-transferase (GST) activities and blood selenium
levels were determined in streptozotocin (STZ)-induced diabetic mice. The effect
of oral administration of sodium selenite was studied on the above parameters.
Diabetes caused hyperglycemia (2.8-fold increase) with a significant increase in
the malondialdehyde levels (89% in liver and 83% in blood) and GST activity (55%)
and marked decreases in GSH levels (approximately 73% in blood and 79% in liver)
in the 5th week after STZ treatment as compared to normal control animals.
Treatment of STZ-induced diabetic mice with sodium selenite changed these
parameters to near control values in almost all cases. These results suggest that
selenium plays a role in reducing the oxidative stress associated with diabetes.
PMID- 9755801
TI - Possible respect of patient quality of life--without reducing survival expectancy
-in breast cancer treatment.
AB - The treatment of breast cancer by some doctors in all countries and all in some
does not concern itself with quality of life considerations. Partial breast
cancer surgery is possible in cases of neither voluminous nor central tumors, and
surgery can also be partial after pre-surgical chemotherapy reduction. The
apoptotic test for cytostatic choice should assist in obviating toxicities which
are minor for the physician, i.e., alopecia, cardiac lesion, etc, but which are
major for the patient. Cytostatics will be useless in treatment if they are not
apoptogenic. Hormonal treatment may, when there are estrogen receptors involved,
be advantageously combined with chemotherapy. In estrogen receptors absence,
growth factor receptors should be considered, as there is a possible indication
of somatostatin analogs (instead of hormones, which are useless). Quality of life
is mainly determined by the partial character of the surgery, hence by the volume
and localization of the tumor. Cancer screening allows diagnosis when tumors are
smaller as opposed to those which are the object of spontaneous diagnosis. We
even propose screening of dysplasias and their biological treatment between 40
and 50 years--hormonal if the specific cells carry hormone receptors, and based
on somatostatin analogs if they carry growth factor receptors.
PMID- 9755802
TI - The clinical role of growth factors in the treatment of breast cancer.
AB - Growth factors have had an increasingly strong impact in breast cancer management
in recent years. The main role of growth factors, particularly hematopoietic
growth factors, in this setting has been to promote better tolerance of standard
doses, and for the implementation of high-dose chemotherapy in innovative
protocols. After a brief overview of growth factor biology, the current clinical
guidelines for their use in cancer management is reviewed. Finally, the role
growth factors in palliative and curative chemotherapy of breast cancer and
methods to reduce tumor cell contamination of peripheral stem cell harvests will
be discussed.
PMID- 9755804
TI - Primary chemotherapy in breast cancer.
AB - Primary (neoadjuvant) chemotherapy is a rapidly evolving area in the management
of early operable breast cancer. This approach achieves significant responses in
around 80% of patients, with a reduction in the need for immediate mastectomy in
patients presenting with large primaries, with no evidence of increased local
recurrence. So far randomised trials suggest that survival is as good with
primary chemotherapy as with post-operative adjuvant chemotherapy. Primary
chemotherapy offers the potential short term tumour response as a predictor for
longer term survival. More importantly, it allows serial biological measurements
of treated breast cancers which, in turn, may aid the selection of appropriate
treatment for individual patients and allow the rapid assessment of new
therapies.
PMID- 9755803
TI - Diet and risk of breast cancer: major findings from an Italian case-control
study.
AB - A large case-control study (2,569 women with breast cancer and 2,588 control
women) carried out in Italy between 1991 and 1994 permits elucidation of breast
cancer risk in relation to dietary patterns in a southern European population.
Major findings include direct associations with the intake of bread and cereal
dishes, sugar, and pork meat, and inverse associations with the intake of
vegetable oils, raw vegetables, fish, beta-carotene, vitamin E, and calcium.
PMID- 9755805
TI - New endocrine approaches in the treatment of breast cancer.
AB - As a result of tamoxifen becoming the first endocrine compound with proven
activity in breast cancer, a. broad spectrum of new substances have been tested
and several are now available for clinical use. New pure antiestrogens show no
estrogenic activity as a result of different receptor binding, and some other
derivatives of tamoxifen demonstrate varied toxicity profiles. The second and
third generation of aromatase inhibitors can selectively inhibit the aromatase
enzyme in the peripheral tissue and perhaps even in tumor cells. Gonadotrophin
releasing hormone (GnRH)-analogues can suppress ovarian function in premenopausal
patients and thus prevent surgical ovarectomy. The value of a new group of anti
progestional substances has not yet been clarified. In this overview the most
important compounds are reviewed for efficacy and toxicity in breast cancer
patients.
PMID- 9755806
TI - A review of breast cancer chemoprevention.
AB - Breast cancer remains a major cause of mortality and morbidity, and may be
amenable to chemoprevention as estrogen stimulation is believed to be responsible
for the promotion of this disease. Tamoxifen is the most widely studied compound
for chemoprevention and clinical trials involving over 20,000 women world-wide
are currently underway. This drug is well-tolerated with low acute toxicity and
high compliance, and has a favorable profile in both decreasing serum cholesterol
and increasing bone mineral density in postmenopausal women. However, there are
fears of its potential carcinogenicity, especially an increased risk of
endometrial cancers, which may jeopardize further recruitment and compliance of
women in these chemoprevention studies. Meta-analyses of these studies are
expected to be conducted in the year 2000 to address the efficacy of tamoxifen in
women with an increased familial predisposition and in those with known germline
BRCA mutations.
PMID- 9755807
TI - Suppression of alloreactivity with gamma delta T-cells: relevance to increased
gamma delta T-cells following bone marrow transplantation.
AB - Several reports have shown that an increase in T-cell receptor gamma/delta
positive T-cells (gamma delta T-cells) have been observed following bone marrow
transplantation. gamma delta T-cells expanded from peripheral blood mononuclear
cells from normal volunteers were used to investigate the function of gamma delta
T-cells in vitro. Peripheral blood mononuclear cells were cultured with synthetic
ligand of gamma delta T-cells, monoethyl phosphates (MEP), for 7 days. MEP
specifically expanded gamma delta T-cells. Expanded gamma delta T-cells from
subject "B" were added to an A anti-B or A anti-C mixed lymphocyte culture (MLC)
containing responder cells from subject "A" and irradiated stimulator cells from
subjects "B" or "C". The cultures were harvested on day 6 and tested for
cytotoxicity against stimulator-type Con A blasts. gamma delta T-cells from
subject "B" specifically inhibit generation of allospecific cytotoxic T
lymphocytes (CTL) in A anti-B MLC. The results indicate that gamma delta T-cells
exhibit veto-type suppression of alloreaction. If the current experiments are
also applicable in vivo, gamma delta T-cells originating from the donor after
bone marrow transplantation may inhibit graft rejection by suppressing recipient
anti-donor reactivity. gamma delta T-cells may be involved in the suppression of
allogeneic reaction in vivo following allogeneic bone marrow transplantation.
PMID- 9755808
TI - Mode-actions of the Na(+)-Ca2+ exchanger: from genes to mechanisms to a new
strategy in brain disorders.
AB - Mode-actions of the Na(+)-Ca2+ exchanger from genes to mechanisms to a new
strategy for brain disorders were comparatively studied in oxidative stress. In
transfected Chinese hamster ovary (CHO) cells steadily expressing the Na(+)-Ca2+
exchanger's gene, Ca(2+)-efflux via an active mode of the Na(+)-Ca2+ exchanger
was elicited by hydrogen peroxide (H2O2) after preincubation of the cell with a
Ca(2+)-free medium, whereas Ca(2+)-influx via a reverse mode of the Na(+)-Ca2+
exchanger was dramatically evoked by H2O2 after preincubation of the cell with a
Ca2+ medium, as a prelude to neuronal death. According to [45Ca2+] uptake of
transfected CHO cells at given time intervals or extracellular Na+[Na+]o
gradients, hyperbola, logarithmic and sigmoid curve equations of the Na(+)-Ca2+
exchanger's mode-actions were respectively defined in the absence and the
presence of H2O2. The Na(+)-Ca2+ exchanger's conformational transition in
oxidative stress was dominated by adenosine triphosphate (ATP)-dependent
cytoskeletal redox modification, cation-pi interactions and secondary Ca2+
activation. These mechanisms were used to generate an intracellulary distributed
tetra-cluster (named VISA931) for rescuing G-protein agonist-sensitive signal
transduction and cortico-cerebral somatosensory evoke potential (SEP) from
oxidation via activating forward operation of the Na(+)-Ca2+ exchanger, the beta
adrenergic and the P2-purinergic receptors, blocking Ca2+ influx and catalyzing
the dismutation of superoxide anions (O2-.) to H2O2. In conclusion, knowledge
based drug design is a new strategy for developing promising candidates of
neuroprotective agents.
PMID- 9755809
TI - Effect of pyridoxal 5'-phosphate on human neutrophil respiratory burst and
adhesion on serum coated microplates.
AB - The effect of pyridoxal 5'-phosphate (PP) on human polymorphonuclear leukocytes
respiratory burst and on cellular adhesion on serum coated microplates was
investigated. No dose-response effect was observed after 10 min pre-treatment at
37 degrees C of human neutrophils with increasing doses of PP, ranging from 0.05
mM/L to 0.5 mM/L. The production of superoxide anion (O2-), after challenging
cells with 0.5 pM/L formyl-methyonyl-leucyl-phenylalanine, 50 ng/mL phorbol
myristate acetate or 50 pg/mL concanavalin A was comparable to that observed by
pre-treating cells with phosphate buffered saline only (control, no PP),
therefore indicating that PP did not affect neutrophil respiratory burst in our
assay conditions. Evaluation of the effect on cellular adhesion onto fetal bovine
serum pre-coated microplates produced the same results. As previous results
showed that PP in the range of 0.01 mM/L to 0.6 mM/L proved to be an efficient
inhibitor of neutrophil aggregation, the evidence reported here might contribute
to establish PP as a good in vitro leukocyte anti-aggregant which does not affect
other functional parameters.
PMID- 9755810
TI - Protective effect of Crassostrea gigas extract on audiogenic seizures in
magnesium deficient mice.
AB - Audiogenic seizures associated with loss of weight, prostration, piloerection,
palpebral ptosis and motor deficiency were induced after sound stimulation of
determined frequency and amplitude in magnesium-deficient DBA/2 mice. These
symptoms were maintained when standard diet conditions (1700 ppm Mg2+) were
restored. In contrast, mice were protected from audiogenic seizure in a dose
related manner when Crassostrea gigas extract (JCOE) were added to the diet for
10 consecutive days. Although a rational explanation for this protective effect
has not yet been determined, it is assumed that it might be due to a chelating
complex formed between Mg2+ and taurine, which enhance the uptake of Mg2+.
PMID- 9755811
TI - Relation between the osmolality trend and ornithynedecarboxylase activity in red
blood cells of uremic patients during hemodialytic treatment.
AB - In uremic patients during chronic hemodialysis an increase in the volume of red
blood cells is observed. Contemporaneously there is an increase in
intraerythrocytic ornithynedecarboxylase activity beyond the normal content (P <
0.01), a high level of seric and plasmatic polyamines (P < 0.01) and a decrease
in seric osmolality (P < 0.01) with pH improvement. The trends of osmolality,
ornithynedecarboxylase, mean cell volume and pH are significantly related. Our
data support the hypothesis that, during hemodialysis, red blood cell volume
changes and increased ornithynedecarboxylase activity are dependent on the
general improvement of plasma tonicity. Moreover, the absence of inhibition of
ornithynedecarboxylase activity by high levels of putrescine is noted.
PMID- 9755812
TI - Relationship between amine-carboxyboranes and TNF alpha for the regulation of
cell growth in different tumor cell lines.
AB - The amine-carboxyboranes were shown to be synergistic with tumor necrosis factor
alpha (TNF alpha) in cytotoxicity and inhibition of DNA synthesis in select types
of cancer cells depending on the presence of a TNF alpha high affinity receptor
on the membrane of the cell. Initially both TNF alpha and the amine
carboxyboranes reduce the influx of calcium but later cause a significant
increase intracellularly. This influx is not linked with the amine-carboxyborane
activating the calcitonin receptor in the tumor cells. Neither the agents nor TNF
alpha directly inhibits DNA topoisomerase II activity but both did cause
decreased phosphorylation of the enzyme by protein kinase C (PKC). The two agents
caused synergistic inhibition. This event correlated with increased DNA protein
linked breaks, DNA fragmentation and cell death. These protein linked breaks are
additive with etoposide's effects but the latter agent's mechanism is different
than phosphorylation of topoisomerase II. There was no evidence that the DNA
fragmentation was caused by a calcium induced endonuclease enzyme in these cancer
cells. The low-molecular weight amine-carboxyboranes appear to play an identical
function as TNF alpha in its role to cause DNA breaks and fragmentation to cause
apoptosis.
PMID- 9755813
TI - Ca2+ dependent purinergic regulation of p42 and p44 MAP kinases in astroglial
cultured cells.
AB - Adenosine triphosphate (ATP) is a signaling molecule for brain cells including
astrocytes. In these cells, it has been shown that ATP stimulates myelin basic
protein (MBP) kinase activity which is believed to represent the Erk family of
MAP kinases. Indeed, we show that ATP activates simultaneously MBP kinase
activity and phosphotyrosine incorporation in p42 Erk2 and p44 Erk1. Maximal
effect of ATP is obtained at 50 microM after 5 min and disappears after 60 min.
Effect of ATP is mimicked by 2-methylthio-ATP whereas alpha beta
methyleneadenosine 5' triphosphate (AMP-CPP) and adenosine do not promote any
effect. Uridine triphosphate (UTP) activates also p42 and p44 MAP kinases. These
observations indicate that p42-p44 MAP kinases activation can be obtained through
P2v and P2u receptors. Purinergic stimulation of Erk is insensitive to pertussis
toxin which inactivates heterotrimeric Gi protein. It is not inhibited by a PLA2
inhibitor (4 bromophenacyl bromide [B phi B]) and the PI3 kinase inhibitor,
wortmannin. In contrast, purinergic stimulation of Erk is partially inhibited by
the PKC inhibitor. GF109203X, at 5 microM and suppressed when extracellular
calcium is complexed by ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'
tetraacetic acid (EGTA).
PMID- 9755814
TI - Iatrogen male infertility.
PMID- 9755815
TI - Genetic diseases of the seminal ducts.
AB - Azoospermia due to an obstruction of the genital tract is one of numerous
possible pathophysiologic mechanisms underlying male infertility. The blockage of
the seminal ducts may be acquired or congenital. Only recently has the strong
association between mutations in the cystic fibrosis transmembrane conductance
regulator (CFTR) gene and various subtypes of obstructive azoospermia been
elucidated. Most patients with congenital bilateral absence of the vas deferens
or bilateral ejaculatory duct obstruction are carriers of such mutations. The
relationship between abnormal CFTR alleles and unilateral absence of the vas
deferens, isolated seminal vesicle anomalies, and Young syndrome is less well
characterized and awaits further investigation.
PMID- 9755816
TI - Ethical aspects of in vitro fertilization and embryo transfer.
AB - In vitro fertilization and embryo transfer (IVF-ET) confronts moral reflection
with a wide range of concerns. Some are similar to those raised by artificial
insemination such as the procurement of sperm, the goods of marriage and donor
gametes. Others are unique to IVF-ET such as surrogacy, the status of the embryo
and cryopreservation.
PMID- 9755817
TI - Somatostatin release in response to glucose is impaired in chronic renal failure.
AB - In order to evaluate somatostatin (SRIH) secretion in uremia, plasma SRIH
concentrations were determined in basal conditions and after an oral glucose
tolerance test (OGTT) in 14 non-dialysed patients with chronic renal failure
(CRF), seven of whom had normal glucose tolerance (NGT) and seven impaired
glucose tolerance (IGT). Plasma insulin, C-peptide and glucagon and blood glucose
concentrations were also evaluated. The results were compared with those obtained
in a group of age- and sex-matched normal subjects. In CRF patients, plasma SRIH
fasting values (8.6 +/- 0.6 and 7.8 +/- 0.6 pmol/L in NGT and IGT patients,
respectively) were comparable to those recorded in controls (7.7 +/- 0.5 pmol/L).
SRIH response to OGTT, evaluated as area under curves (AUC) above basal, was
similar in both groups of CRF patients (412.9 +/- 84.5 and 415.6 +/- 51.9 pmol/L
per min), and significantly lower than in controls (660.1 +/- 58.5 pmol/L per
min). Data indicate that chronic uremia induces a loss of SRIH secretory cell
responsiveness to glucose. A possible effect of impaired SRIH secretion on
glucose metabolism in CRF is discussed.
PMID- 9755818
TI - GABA modulates cytotoxicity of immunocompetent cells expressing GABAA receptor
subunits.
AB - C57 black mouse splenic T lymphocytes effector cells were co-cultivated with
Balb/c mouse splenic cells for sensitization; P815 DBA mouse mastocytoma target
cells were then added and specific T cell-dependent cytotoxicity determined. This
cytotoxicity increased after gamma-aminobutyric acid (GABA) treatment of the
sensitized effectors, but decreased after GABA treatment of the targets. These
GABA effects seemed to be specific since they were partially mimicked by linear
but not ramified GABA analogues. Furthermore, they were likely mediated by GABAA
receptor since GABAA receptor subunit mRNAs and protein could be demonstrated in
effector or target immune specific cells, suggesting that under yet to be defined
circumstances, GABA may affect T cell functions.
PMID- 9755819
TI - Epidemiological study of p53 tumor suppressor gene mutations in patients from
Luxembourg and the German Saar region with an advanced colorectal cancer using
PCR-SSCP analysis.
AB - Mutations in the p53 tumor suppressor gene are usually associated with an
advanced development of colorectal cancer characterized by the transition from
the adenoma to the carcinoma stage. We used the polymerase chain reaction (PCR)
followed by single-strand conformation polymorphism (SSCP) analysis to screen for
the presence of mutations in the p53 gene of patients from Luxembourg and the
German Saar region with colorectal cancers at various developmental stages. While
we detected no mutations in 16 colic polypi at an early to intermediate stage
(adenoma), we revealed seven (13.7%) non-silent point mutations (transitions) in
exons 5 to 9 of the p53 gene in 51 colorectal tumors at a late stage (carcinoma).
In addition to confirming previous observations, these results show that PCR-SSCP
analysis can provide both a sensitive and rapid method for the genetic
determination of the histopathological stage of colorectal samples.
PMID- 9755821
TI - Ajoene [(e,z)-4,5,9-trithiadodeca-1,6,11-triene 9 oxide] does not exhibit
antiviral activity at subtoxic concentrations.
PMID- 9755820
TI - Selective in vitro protection of SIVagm-induced cytolysis by ajoene, [(E)-(Z)
4,5,9-trithiadodeca-1,6,11-triene-9 oxide].
AB - We studied the effect of synthetic ajoene on simian immunodeficiency virus
(SIVagm)-mediated cell fusion and subsequent virus-induced cytolysis. Our data
indicate that this compound is a strong antifusion agent with a 50% syncytium
inhibitory concentration (SIC50%) value of about 2.9 microM. We suggest that
ajoene interacts with the cell-specific integrin molecules and sterically hinders
the association between fusion (or other co-receptors) and the CD4-gp120 complex
at the cell surface of SIV-infected cells. Although ajoene was maximally
effective in suppressing syncytium formation during the early period (ie, up to 6
h) of the fusion process, when the compound was recurrently added to the co
cultures, the inhibitory effect was regained and further cell death was markedly
delayed. This indicates that ajoene was also effective after the initial cell-to
cell contact stage. These data suggest that ajoene may be a promising approach
for the treatment of SIV/human immunodeficiency virus (HIV) infections.
PMID- 9755822
TI - The cells are mortal or immortal, divide and disappear with reincarnation or
after metabolic or apoptotic death.
PMID- 9755823
TI - The central role of the mitochondrial megachannel in apoptosis: evidence obtained
with intact cells, isolated mitochondria, and purified protein complexes.
AB - The mitochondrial megachannel (also called permeability transition pore) is a
polyprotein complex formed in the contact site between the inner and the outer
mitochondrial membranes and participates in the regulation of mitochondrial
membrane permeability. We have obtained three independent lines of evidence
suggesting the implication of the mitochondrial megachannel in apoptosis. First,
in intact cells, apoptosis is accompanied by an early dissipation of the
mitochondrial transmembrane potential (delta psi m). In several models of
apoptosis, specific agents inhibiting the mitochondrial megachannels prevent this
delta psi m dissipation and simultaneously abolish the manifestations of caspase-
and endonuclease activation, indicating that megachannel opening is a critical
event of the apoptotic process. Second, mitochondria are rate-limiting for
caspase and nuclease activation in several cell-free systems of apoptosis.
Isolated mitochondria release apoptogenic factors capable of activating pro
caspases or endonucleases upon opening of the mitochondrial megachannel in vitro.
Third, opening of the purified megachannel reconstituted into liposomes is
inhibited by recombinant Bcl-2 or Bcl-XL, two apoptosis-inhibitory proteins which
also prevent megachannel opening in cells and isolated mitochondria. This
indicates that the megachannel is under the direct regulatory control of anti
apoptotic members of the Bcl-2 family. Altogether, our results suggest that
megachannel opening is sufficient and (mostly) necessary for triggering
apoptosis.
PMID- 9755824
TI - Importance of DNA fragmentation in apoptosis with regard to TUNEL specificity.
AB - In the absence of a universal specific molecular tracer of apoptosis, structural
DNA alterations provide the basis of labeling systems: double-strand
fragmentation for TUNEL (terminal transferase-mediated dUTP nick end-labeling),
denaturation for poly (A) in situ hybridization, immunogenicity of single strand
DNA, all methods which imply limited specificity due to the unavoidable presence
of DNA breaks in virtually all cells. Thus, TUNEL application has been restrained
to a narrow spectrum of sample conditions which has limited, in particular,
retrospective surveys and apoptotic nuclei-protein double labelings. In the
apoptotic nucleus two main obstacles intervene between TUNEL reagents and their
targets: DNA hypercondensation and proteins around DNA. The former increases in
the course of apoptosis and both are worsened by crosslinking and precipitating
fixatives. This point out that TUNEL is an ambitious approach whose target,
apoptotic DNA breaks, is less accessible than breaks occurring in non-apoptotic
less compacted DNA. However, TUNEL has an advantage: the far greater degree of
apoptotic DNA fragmentation. How to obtain a frank differential staining between
apoptotic and non-apoptotic DNA? It appears that the answer relies on the
pretreatment step and not in modifying the TUNEL staining protocol, which is
optimal. Adapted pretreatments are able to circumvent accessibility obstacles and
to extend TUNEL applicability to the most demanding conditions, those of archived
tissue samples and of TUNEL--protein double labelings.
PMID- 9755825
TI - Apoptosis and liver fibrosis: antifibrotic strategies.
AB - Hepatic fibrosis is a frequent response of the liver and is similar to
parenchymal wound healing in other tissues. Apoptosis has been described in
different models of liver fibrosis. Hepatic stellate cells are the main source of
extracellular matrix. At present, one can speculate that inhibition of apoptosis
is responsible for activation and proliferation of hepatic stellate cells. Thus,
the inhibition of hepatic stellate cell apoptosis could be a target for
antifibrotic strategies. Until now, no drugs have been clearly shown to be
effective in reducing specifically the development of hepatic fibrosis. However,
serious candidates are presently under studies in clinical trials, including
especially alpha interferon and phosphatidylcholine.
PMID- 9755826
TI - Apoptosis and programmed cell death: a role in cerebral ischemia.
AB - Hypoxic-ischemic neuronal death has long been considered to represent necrosis,
but it now appears that many brain neurons undergo apoptosis after either global
or focal ischemic insults. Recent studies demonstrated: 1) DNA cleavage into
oligonucleosome-sized fragments demonstrated by a typical ladder pattern; 2)
early endonuclease activation, as demonstrated by the presence of high molecular
weight DNA fragments (300 to 50 kbp); 3) chromatin condensation and apoptotic
bodies formation; 4) activation of apoptosis-associated proteins. These results
may indicate that apoptosis contributes to the development of the ischemic
infarct and is probably substantially distinct from ischemia-triggered
excitotoxicity, which tends to produce necrosis.
PMID- 9755827
TI - 3-Bromoacetylamino benzoylurea (3-BAABU), a new antimicrotubule cancericidal
agent applied in cytogenetic analysis in hematology.
AB - 3-Bromoacetylamino benzoylurea (3-BAABU) is a newly synthesized antimicrotubule
cancericidal compound. In the present study, we investigated the possibility of
using 3-BAABU as a mitotic blocking agent for hematologic karyotyping. Treatment
with 3-BAABU caused scattering of metaphase chromosomes throughout the cytoplasm
both in phytohemagglutinine (PHA)-stimulated human lymphocytes and in human
leukemic cells. Kinetic showed a rapid uptake of 3-BAABU by treated cells and
irreversibility of its effect. Using 3-BAABU in routine procedure, a karyotype of
lymphocytes from a normal male was 46, XY, with normal structure and CEM leukemic
line was 85, XX, in a representative spread with abnormalities similar to reports
using other blocking agents. Using 3-BAABU in spectral karyotyping, details of
translocations in CEM leukemic cells were readily detected in several
chromosomes, such as 7 [t(7;11)], 8 [t(8;9)], 9 [t(8;9) & t(9;19)], 11 [t(7;11)],
16 [t(16;18;20)] and 20 [t(1;20)]. 3-BAABU displayed two important characters in
cytogenetics, 1) it caused dispersion of chromosomes, avoiding chance of overlap;
2) compared to the conventional mitotic blocking agent, vinblastine sulfate, 3
BAABU exhibited much gentle effect on chromosomes, thus providing more
flexibility in time to perform karyotyping.
PMID- 9755828
TI - Structurally different anthracyclines provoke different effects on cell cycle and
tumor B cell differentiation.
AB - Previously we have detected a stimulatory effect on immunoglobulin (IgG)
synthesis when hybridoma cells were treated with doxorubicin. In order to
determine whether this is a general property of anthracycline, we have selected
three analogs--doxorubicin (DOX), pirarubicin (THP-DOX) and aclarubicin (ACR)-
which differ mainly in the methylation state of their amino sugars. Cell cycle
analysis by flow cytometry and drug localization by scanning confocal microscopy
were also performed. The results show that when cells (UN2 hybridoma B cells),
were exposed to subtoxic doses of DOX or THP (with unmethylated amino sugars), a
strong increases in IgG secretion, heavy (H) and light (L) chain synthesis and
the corresponding mRNA levels were induced. Furthermore these two drugs arrested
the cells in the G2/M phase of the cell cycle. In contrast, exposure to ACR (with
its methylated amino sugar) at similar subtoxic doses induced a blockade of cells
in the G1 phase with no increase of IgG synthesis, at the subtoxic doses used,
all three drugs could still be detected in the nucleus as well as in the
cytoplasm, as determined by confocal laser microscopy. Thus, the relationship
between cell cycle blockade, IgG stimulation and anthracycline structure is
suggested by these results.
PMID- 9755829
TI - [Laboratory and clinical studies on tazobactam/piperacillin in the field of
pediatrics].
AB - Laboratory and clinical studies on tazobactam/piperacillin (TAZ/PIPC), a
combination drug of piperacillin (PIPC) with the new beta-lactamase inhibitor
tazobactam (TAZ), were carried out in the field of pediatrics. 1. After
intravenous administration of TAZ/PIPC at a dose of 25 mg/kg to one child, the
peak plasma levels of TAZ and PIPC were 24.4 micrograms/ml and 119 micrograms/ml
respectively after 5 min. The half-lives of TAZ and PIPC were 0.48 and 0.60 hours
respectively. Same as 50 mg/kg to two children, the peak plasma levels of TAZ and
PIPC were 17.5, 32.2 micrograms/ml and 92.8, 163 micrograms/ml after 5 min. The
half-lives of TAZ and PIPC were 0.37, 0.50 hours and 0.51, 0.59 hours. A ratio of
TAZ to PIPC was about 1 to 4 in plasma levels. The cumulative urinary recovery
rates of TAZ and PIPC in the first 6 hours after intravenous administration were
15.8, 64.9% and 39.8, 53.4%. 2. The antibacterial activity of TAZ/PIPC against
clinically isolated organisms was determined. The MICs of TAZ/PIPC were < or =
0.05 microgram/ml against Haemophilus influenzae and Streptococcus pneumoniae and
> or = 1.56 micrograms/ml against Escherichia coli, Staphylococcus aureus and
Haemophilus parainfluenzae. 3. The clinical efficacy of TAZ/PIPC could be
evaluated in 14 patients with various bacterial infections, and was evaluated as
"excellent" in 9 patients and as "good" in 5. The overall clinical efficacy rate
in 14 cases was 100% and excellent was 64.3%. Bacteriological efficacy rate was
91.7% (10/11). 4. As a side effect, loose stool was observed in one case, no
abnormal laboratory test values were observed. It has been concluded that
TAZ/PIPC was a useful drug in the field of pediatrics.
PMID- 9755830
TI - [Fundamental and clinical studies on tazobactam/piperacillin in the pediatric
field].
AB - Pharmacokinetics, efficacy and safety of tazobactam/piperacillin (TAZ/PIPC), a
new beta-lactamase inhibitor combined with a penicillin antibiotic, were studied
in pediatrics and the following results were obtained. 1) Serum concentration and
urinary excretion of TAZ/PIPC after intravenous administration at a dose of 46
mg/kg to one child were investigated. Serum half-lives were 0.5 hours for TAZ and
0.6 hours for PIPC, while the urinary recovery rates in the first 6 hours after
administration, were 61.6% and 56.3% respectively. 2) TAZ/PIPC was administered
at a dose of 46.0-73.5 mg/kg t.i.d. for 3-13 days to 10 patients, 6 with
respiratory infection, 1 with pharyngotonsillitis, 1 with pertussis and 2 with
soft tissue infection of skin. Clinical response were excellent in 5 cases and
good in 5 cases, and the efficacy rate was 100%. Bacteriologically, 2 strains
(Staphylococcus aureus and Streptococcus pyogenes) isolated from 2 patients were
eradicated after the treatment. As for adverse reaction, mild skin rash was
observed in 1 case but disappeared within 2 days after withdrawal of the drug. As
for abnormal laboratory test results decrease in neutrophiles and increase in
eosinophiles in each 1 case were observed, which were, however, normalized after
administration. From the above results, tazobactam/piperacillin was considered to
be a useful antibiotic in the pediatric field.
PMID- 9755831
TI - [Basic and clinical studies on tazobactam/piperacillin in pediatric field].
AB - A drug susceptibility test of the combination drug TAZ/PIPC, which consists of a
newly developed beta-lactamase inhibitor, tazobactam (TAZ), and one of penicillin
antibiotics, piperacillin (PIPC), with combination ratio of 1:4 in potency, was
conducted with stock strains and clinical isolates. The clinical efficacy and
safety of its injection was also evaluated in children with a variety of
infectious diseases. The results were as follows: 1. In susceptibility test, 114
strains from 4 species of stock strains were treated with 8 drugs, that is,
TAZ/PIPC, PIPC, penicillin G (PCG), ampicillin (ABPC), cefotiam (CTM), cefotaxime
(CTX), ceftazidime (CAZ), and sulbactam/cefoperazone (SBT/CPZ). Of three
clinically isolated species from patients, Staphylococcus aureus (S. aureus) was
treated with TAZ/PIPC, PIPC, methicillin (DMPPC), CTM, CTX, and SBT/CPZ, and the
others were treated with the same drugs except for DMPPC. The MICs were measured
for these bacterial strains inoculated at the concentration of 10(6) CFU/ml. The
MIC90 values of TAZ/PIPC against 45 strains of Streptococcus pyogenes (S.
pyogenes), one of the stock cultures of Gram-positive cocci, were 0.05
microgram/ml and similar to those of PIPC, CTM, CAZ, and SBT/CPZ. The MICs of
TAZ/PIPC for 28 strains of Streptococcus agalactiae (S. agalactiae) were 0.39
microgram/ml and similar to those of PIPC, CTM, CAZ, and SBT/CPZ. As for Gram
negative bacilli, the MIC90 of TAZ/PIPC against 10 strains of Bordetella
pertussis (B. pertussis) were 0.10 microgram/ml and similar to those of PIPC. The
MIC90 of TAZ/PIPC against 31 strains of Haemophilus influenzae (H. influenzae)
were 0.05 microgram/ml and similar to those of PIPC, CTX, and SBT/CPZ. Regarding
Gram-positive cocci isolated from patients received this combination drug, the
MIC90 of TAZ/PIPC against 2 strains of S. aureus, a non beta-lactamase producing
strain and a low-beta-lactamase producing strain, were 0.78 microgram/ml and 3.1
micrograms/ml, respectively; the former value was similar to those of PIPC,
DMPPC, CTM, and CTX, and the latter was similar to those of PIPC, DMPPC, CTX, and
SBT/CPZ. Of 4 strains of Streptococcus pneumoniae, 2 strains were inhibited at
0.05 microgram/ml, and the others at 1.56 micrograms/ml; both values were similar
to those of PIPC, SBT/CPZ. As for Gram-negative bacilli, 6 of 7 strains of H.
influenzae did not produce beta-lactamase and 1 strain was a high producer. The
MICs of TAZ/PIPC against beta-lactamase nonproducing strains were < or = 0.025
microgram/ml in 5 strains and 0.39 microgram/ml in 1 strain, and the values were
similar to those of PIPC and SBT/CPZ. While the MIC of TAZ/PIPC against the high
beta-lactamase producing strain was 0.78 microgram/ml; similar to that of SBT/CPZ
and smaller than that of PIPC. 2. The results of clinical effects on 7 diseases
in 33 cases were as follows: TAZ/PIPC was clinically judged "excellent" in 17
(51.5%); good in 14 (42.4%); fair in 2 (6.1%). No case with no response was seen
in this study, and the total efficacy rate of "excellent" and "good" was 93.9%.
3. Bacteriological effects were evaluated in 17 strains of 4 species, and all of
them were eradicated. 4. Adverse reactions were judged in 35, which consisted of
33 in which the clinical effects were evaluated and 2 dropped from this study. Of
these cases, diarrhea was observed in 4 (11.4%). 5. Laboratory tests revealed an
increase in platelets in 1 of 32 cases (3.1%), and eosinophilia in 2 of 29 cases
(6.9%). Biochemical profile showed an increase in GPT alone and abnormal
increases in both GOT and GPT in 1 each out of 21 cases.
PMID- 9755832
TI - [Transferability of tazobactam/piperacillin (TAZ/PIPC) to cerebrospinal fluid of
rabbit with meningitis caused by Staphylococcus aureus].
AB - The transferability of tazobactam/piperacillin (TAZ/PIPC) to cerebrospinal fluid
(CSF) was studied employing rabbits with experimental meningitis caused by
Staphylococcus aureus. 125 or 250 mg/kg of TAZ/PIPC was intravenously
administered to rabbits with experimental meningitis then concentrations of TAZ
and PIPC in CSF and serum were measured. In the group to which 125 mg/kg of
TAZ/PIPC was administered, mean concentration of TAZ in CSF was 7.3 and 2.4
micrograms/ml at 30 and 60 min after administration, respectively, and concerning
PIPC, it was 10.1 and 3.5 micrograms/ml, respectively. CSF/serum ratio of TAZ was
29.4% and 31.4%, respectively, and that of PIPC was 24.3 and 35.6%, respectively.
In the group to which 250 mg/kg of TAZ/PIPC was administered, mean concentration
of TAZ in CSF was 16.5 and 12.6% micrograms/ml, respectively, and concerning
PIPC, it was 25.6 and 18.2 micrograms/ml, respectively. CSF/serum ratio of TAZ
was 22.1 and 56.1%, respectively, and that of PIPC was 12.2 and 51.9%,
respectively. Addition of TAZ did not make significant change of transferability
of PIPC to CSF. Considering the antibacterial effect of TAZ/PIPC against main
causative organism of meningitis, this agent was thought to be effective for the
treatment of purulent meningitis.
PMID- 9755833
TI - Fibrinolytic proteins in apoptotic human umbilical vein endothelial cells.
AB - Endothelial cells express fibrinolytic proteins including: urokinase (u-PA) and
tissue type (t-PA) plasminogen activators, type-1 (PAI-1) and 2 (PAI-2)
plasminogen activator inhibitors, and u-PA receptor (u-PAR). Apoptotic
endothelial cells detach, potentially forming both local and circulating
microthrombi in vivo. In this article, apoptotic human umbilical vein endothelium
was obtained by serum starvation and compared with nonapoptotic cells rescued
from death with fresh medium containing serum. Antigen levels for t-PA, PAI-1,
PAI-2, and u-PAR were reduced greatly in apoptosis (p< 0.05). In contrast, u-PA
levels were similar in apoptotic as compared with rescued cells (p<0.05).
Radioactive amino acids were used to determine absolute levels of protein
synthesis and degradation in these cells. Reduced antigen levels likely were due
to proteolysis as there was 98% total protein degradation and very little protein
synthesis in apoptotic endothelial cells. Also, u-PA levels in apoptotic
endothelial cells were not affected by the protein synthesis inhibitor
cycloheximide. Endothelial cells in inflammatory sites are exposed to cytokines,
which increase both apoptosis and u-PA levels. Data from this article support the
idea that maintained u-PA levels in apoptotic endothelium may protect from micro
thrombosis in inflammatory sites as well as in the circulation.
PMID- 9755834
TI - The effect of danaparoid sodium (danaparoid) on endotoxin-induced experimental
disseminated intravascular coagulation (DIC) in rats.
AB - Danaparoid sodium (danaparoid) is a low molecular weight heparinoid with
anticoagulation properties, which mainly consists of heparan sulfate. Compared
with heparin sodium (heparin), danaparoid has a much higher anti-Xa/anti-thrombin
ratio. We compared the effect of danaparoid on endotoxin-induced experimental
disseminated intravascular coagulation (DIC) in rats with heparin. A bolus
injection of endotoxin (10 mg/kg) induced gradual decreases in the platelet
count, and the plasma fibrinogen, antithrombin III (AT-III) and heparin cofactor
II levels, as well as an increase in the fibrinogen/fibrin degradation products
level from 1 to 6 hours after the injection, indicating that both coagulation and
fibrinolysis were activated. The intravenous administration of danaparoid or
heparin 3 hours after the endotoxin injection inhibited the endotoxin-induced
decreases in the platelet count and plasma fibrinogen level and also inhibited
the endotoxin-induced increase in glomerular fibrin deposition in the kidney.
Differences between danaparoid and heparin were observed in their effects on the
plasma AT-III level and clotting time. Danaparoid significantly inhibited both
the decrease in the plasma AT-III level and the prolongation of the prothrombin
time induced by endotoxin, where as heparin showed no effect on those responses.
Moreover, danaparoid enhanced the prolongation of the activated partial
thromboplast in time induced by endotoxin to a lesser degree than heparin. These
findings suggest that the effects of danaparoid on the endotoxin-induced decrease
of the plasma AT-III level and the prolongation of the clotting time are more
advantageous than those of heparin. The results may have been due to a higher
anti-Xa/anti-thrombin ratio of danaparoid than that of heparin, indicating that
danaparoid may be useful in the treatment of DIC.
PMID- 9755835
TI - A new thromboxane receptor antagonist, Z-335, ameliorates experimental thrombosis
without prolonging the rat tail bleeding time.
AB - We investigated the antithrombotic activity of Z-335, a new thromboxane A2
receptor antagonist, using experimental thrombosis models, and also tested its
effect on the rat tail bleeding time. Z-335 (0.1, 0.3, and 1 mg/kg, p.o.) dose
dependently prevented the occurrence of arachidonic acid-induced pulmonary
thromboembolism in mice. During photochemically induced thrombosis in the femoral
artery of guinea pigs, Z-335 (0.3, 1, and 3 mg/kg, i.v.) dose-dependently
prolonged the time required to form thrombi. Moreover, Z-335 (10 mg/kg/day, p.o.)
strongly suppressed lauric acid-induced hind limb injury in rats. Z-335 (0.3, 3,
30, and 300 mg/kg, p.o.) did not prolong the tail bleeding time in rats. These
results strongly suggest that Z-335 ameliorates experimental thrombosis without
prolonging the rat tail bleeding time, and may therefore be a useful
antithrombotic drug.
PMID- 9755836
TI - A randomized comparison of a computer-based dosing program with a manual system
to monitor oral anticoagulant therapy.
PMID- 9755837
TI - Relative influence of age and thrombotic history on hemostatic parameters.
PMID- 9755838
TI - A simple and rapid method for purifying the extracellular domain of human tissue
factor.
PMID- 9755839
TI - Clinical significance of serum soluble Fas ligand in patients with acute self
limited and fulminant hepatitis.
AB - The Fas ligand (FasL), a member of the tumor necrosis factor family, induces
apoptosis in Fas-expressing cells. A matrix metalloproteinase-like enzyme cleaves
the membrane-bound FasL to produce the soluble FasL (sFasL). Since FasL has been
reported to play a pivotal role in the development of hepatitis, we evaluated
clinical significance of serum sFasL in acute liver injury including acute self
limited and fulminant hepatitis. Serum sFasL in 19 patients including 12 with
acute self-limited hepatitis and 7 with fulminant hepatitis was measured by an
enzyme-linked immunosorbent assay (ELISA). The clinical data consisted of 18
indices including age, sex, liver function tests, hepatocyte growth factor (HGF),
outcome and sFasL. Serum sFasL in fulminant hepatitis is 0.06+/-0.01 ng/ml, being
identical to that in acute self-limited hepatitis, Serum sFasL is positively
correlated with AST and ALT (p<0.0001 and p<0.0001). The factors associated with
outcome of the patients were HGF, albumin, prothrombin time, platelet count,
cholinesterase and leukocyte count in this order. Serum sFasL serves as an
indicator of liver injury in acute self-limited and fulminant hepatitis.
PMID- 9755840
TI - Human colon cancer cells express the functional Fas ligand.
AB - Fas ligand (FasL) belongs to the TNF superfamily. It is induced in activated
lymphocytes and eliminates Fas-positive lymphocytes, resulting in the down
regulation of immune responses. FasL has also been detected in tissues other than
lymphoid cells. We investigated the expression and function of FasL on human
colon cancer cells. FasL mRNA was detected by RT-PCR in all six colon cancer cell
lines tested and was not found on fibroblasts. FasL protein was detected in DLD
1, LoVo, HCT-116 and RPMI 4788 cells by immunohistochemical staining. DLD-1, LoVo
and WiDr were cytotoxic against mouse T lymphoma cells which were transfected
with human Fas receptor cDNA. The cytotoxicity was significantly enhanced by
phorbol 12-myristate 13-acetate (PMA) and ionomycin. Our data suggest that the
FasL expressed in human colon cancer cells may be regulated by endogenous factors
in the microenvironment of the host and facilitates the escape from the host
immune system.
PMID- 9755841
TI - The somatostatin analog, octreotide, inhibits in vitro outgrowth of smooth muscle
cells from canine coronary and carotid atherosclerotic plaque tissues.
AB - Restenosis is caused by excessive neointima formation resulting from smooth
muscle cell (SMC) proliferation and migration from the arterial media into the
subendothelial space, stimulated by growth factors. A long-acting somatostatin
analog, octreotide, activates protein tyrosine phosphatases and can inhibit the
stimulatory effects of growth factors. In this study, we evaluated the effect of
octreotide on SMC outgrowth from in vitro explants of both coronary and carotid
arterial tissues in a canine endothelium-injury model. After 6 days of culture,
SMC grew out of 33.3% and 58.3% of the explants from the injured canine carotid
and coronary arterial tissues, respectively. In contrast, SMC outgrowth was not
observed from any of the explants from normal canine carotid arterial tissue.
Octreotide completely inhibited SMC outgrowth from injured canine carotid
arterial tissue at a concentration of 10(-6) M. This agent also inhibited SMC
outgrowth from injured canine coronary arterial tissue by 57% and 71% of the
control value at concentrations of 10(-8) M and 10(-6) M, respectively. We
conclude that our explant cell-culture model may prove to be valuable for
assessing the effect of agents designed to reduce intimal proliferation, and that
the use of the somatostatin analog octreotide in clinical settings may modify the
high incidence of restenosis after coronary interventions by reducing SMC
proliferation.
PMID- 9755842
TI - Ruthenium red inhibits cytosolic Ca2+ oscillations induced by vasopressin in
primary cultured hepatocytes.
AB - The effects of ruthenium red were investigated on the vasopressin (Vp)-induced
Ca2+ response in single, primary cultured rat hepatocytes loaded with fura-2. Low
concentrations of Vp (1 nM) evoked a sustained train of baseline spike Ca2+
oscillations, with a latency to first peak of 170 s and a frequency of 0.37 min(
1). Treatment of hepatocytes with a higher concentration of Vp (10 nM) resulted
in a rapid rise in intracellular Ca2+, with less delay (40 s), and which remained
elevated and sustained. Microinjection of a low concentration of ruthenium red
(10 microM in the injection pipette) altered the observed response to 1 nM Vp
such that only 2 - 4 base line spikes were observed. A higher concentration of
ruthenium red (50 microM in the injection pipette) completely abolished the 1 nM
Vp response. However, the Ca2+ responses to higher concentrations of Vp (10 nM)
or to the Ca2+-ATPase inhibitor, thapsigargin, were unaffected by ruthenium red.
These results show that low concentrations of ruthenium red inhibit the Vp
induced oscillatory Ca2+ response and suggest a contribution of a ryanodine
receptor-mediated Ca2+-induced Ca2+ release in generating the baseline spike
oscillations in rat hepatocytes.
PMID- 9755843
TI - Magnetically induced motor evoked potentials and H-reflex during nembutal and
ketamine anesthesia administration in rats.
AB - The effects of nembutal and ketamine anesthesia on motor evoked potentials (MEPs)
and spinal segment reflex (H-response, F and M waves) were investigated in rats
by magnetic stimulation. These potentials were generated by magnetic stimulation
of the motor cortex and the spinal cord (L4-L5). After application of nembutal,
MEP and H-response decreased in amplitude, eventually disappearing. The
amplitudes of F and M waves increased and persisted at the increased levels
during anesthesia. The latencies of F and M waves were constant before and after
anesthesia. Following ketamine administration, the threshold, latency and
amplitude of the magnetically induced MEPs, and M, F and H responses were not
influenced systematically. The results suggested that MEPs and H-response
depression and/or disappearance due to synaptic site suppression after nembutal
anesthesia, and the increase and persistence of increased F and M waves
amplitudes were all due to the increasing motoneuron excitability, whereas
ketamine did not affect synaptic sites subjected to magnetic stimulation.
PMID- 9755844
TI - Cell death and cytoskeletal alterations in cultured hepatic fat-storing cells
induced by 6-hydroxydopamine.
AB - We studied the effects of the neurotoxin, 6-hydroxydopamine (6-OHDA), on cultured
fat-storing cells (FSCs) and hepatocytes. If either FSCs or hepatocytes were
exposed to 6-OHDA for 4 hr, the neurotoxicant induced cell death in FSCs but not
in hepatocytes. We decided to investigate why hepatocytes were refractile to
injury from 6-OHDA while FSCs were labile. The activity of antioxidant enzymes
within FSCs grown in vitro is remarkably lower than the activity in hepatocytes.
Indeed, some specific antioxidant enzymes in FSCs were undetectable by our
assays, but were easily detected in hepatocytes. Furthermore, the profile of
antioxidant activity in FSCs was found to be almost identical to the profiles
seen in cultured fibroblasts or myocytes. However, indirect immunolocalization of
tyrosine hydroxylase in FSCs using anti-tyrosine hydroxylase antibodies was
negative. Mazindol, a dopaminergic receptor antagonist, did not alleviate the
toxicity of 6-OHDA suggesting that FSCs do not appear to possess a dopaminergic
receptor. When the cell morphology of FSCs was examined by an indirect
immunofluorescence technique, treatment of FSCs with 6-OHDA at a concentration of
200 microM for 2 hr modified the organization of alpha-smooth muscle actin into
an irregular punctate pattern. Indeed, we found that the effects of 6-OHDA on
cytoskeletal alterations and on the cell viability of FSCs were irreversible.
These data suggest that : (1) 6-OHDA can cause irreparable injury to FSCs, but
not hepatocytes; (2) hepatocytes are specially adapted to withstand an oxidative
attack in contrast to FSCs. fibroblast and myocytes; (3) FSCs resemble other
somatic cells in their low levels of antioxidant enzymes; and (4) this low
profile of antioxidant activity may be responsible for the cell death and
cytoskeletal alterations observed in FSCs in response to 6-OHDA.
PMID- 9755845
TI - Role of tumor necrosis factor-alpha in regulating fibrotic lung repair.
AB - To study the role of tumor necrosis factor-alpha (TNF-alpha) in fibrotic lung
repair, we evaluated changes in lung TNF-alpha content and binding during the
evolution of the fibrotic response. We concomitantly examined the effect of TNF
alpha on lung fibroproliferative responses. Lung TNF-alpha increased early after
injury, at a time when lung tissue and lung fibroblasts exhibited increased
binding to the cytokine. Fibroblasts isolated during this phase, which have
increased spontaneous proliferative activity, had significant reduction in DNA
synthesis when exposed to TNF-alpha. In contrast, DNA synthesis in normal and
repair phase fibroblasts was inhibited by TNF-alpha. We also examined mechanisms
of transduction of the TNF-alpha fibroproliferative signal, and observed that
phosphorylating enzymes and G-proteins were involved. We conclude that TNF-alpha
has a dual role in fibrotic repair. During injury, when uncontrolled fibroblast
proliferation occurs, TNF-alpha production is increased to slow down the
fibroproliferative response. During repair, when fibroblasts participate in
structural restitution, TNF-alpha plays a salutary role by stimulating cellular
proliferation. These effects of TNF-alpha on cellular proliferation are mediated
by activation of two separate signal transduction pathways, phosphorylating
enzymes and G-proteins. The observed variability in the effect of TNF-alpha may
be related to changes in the phenotypic and genotypic characteristics of
repairing lung fibroblasts which alter their responsiveness to exogenous stimuli.
PMID- 9755846
TI - No effect of probenecid on the renal excretion mechanism of a new carbapenem, DA
1131, in dogs.
AB - The effect of probenecid, an anion transport inhibitor, on the renal excretion
mechanism of a new anionic carbapenem, DA-1131, was investigated after 1-min
intravenous infusion of DA-1131, 10 mg/kg, with or without probenecid, 50 mg/kg,
to dogs. The renal clearance (CL(R)) of DA-1131 in dogs without probenecid
(3.18+/-0.247 ml/min/kg) was considerably smaller than the reported creatinine
clearance (CL(CR)) in dogs, 6.13 ml/min/kg, indicating that renal tubular
reabsorption of the drug was observed in dogs. However, the CLR of DA-1131 was
not significantly different (3.18+/-0.247 versus 3.29+/-0.698 ml/min/kg) by
treatment with probenecid indicating that the tubular reabsorption of DA-1131 was
not inhibited by probenecid.
PMID- 9755847
TI - Electroporation-mediated gene transfer in cardiac tissue.
AB - Delivery of genes or macromolecules to cardiovascular tissues provides new
therapeutic opportunities for the treatment of many acquired and inherited
diseases. To investigate electroporation as a delivery method in cardiac tissue,
embryonic chick hearts were studied for uptake of propidium iodide (PI) or DNA
encoding either green fluorescent protein (GFP) or luciferase following
electrical shock. PI uptake increased monotonically from 6% of heart tissue after
3 shocks to 77% with 12 shocks. GFP and luciferase expression varied in
proportion to shock number, with detectable levels in all electrically treated
hearts. Thus, electroporation promotes uptake of PI and DNA in cardiac tissue,
suggesting further application of this method for therapeutic genes.
PMID- 9755848
TI - Rat liver mitochondria can hydrolyse thiamine pyrophosphate to thiamine
monophosphate which can cross the mitochondrial membrane in a carrier-mediated
process.
AB - We show here that TPP --> TMP conversion can take place in rat liver
mitochondria. This occurs via the novel, putative TPP pyrophosphatase localised
in the mitochondrial matrix, as shown both by digitonin titration and by an HPLC
enzyme assay carried out on the mitochondrial matrix fraction. Certain features
of the reaction, including the substrate and pH dependence, are reported.
Additional evidence is given that externally added TMP can cross the
mitochondrial membrane in a manner consistent with the occurrence of a carrier
mediated process. This can occur both via the TPP translocator and via a novel
translocator, inhibited by CAT but different from the ADP/ATP carrier.
PMID- 9755850
TI - Thimet oligopeptidase: site-directed mutagenesis disproves previous assumptions
about the nature of the catalytic site.
AB - Zinc metallopeptidases that contain the His-Glu-Xaa-Xaa-His (HEXXH) motif
generally have a third ligand of the metal ion that may be either a Glu residue
(in clan MA) or a His residue (in clan MB) (Rawlings and Barrett (1995) Methods
Enzymol. 248, 183-228). Thimet oligopeptidase has not yet been assigned to either
clan, and both Glu and His residues have been proposed as the third ligand. We
mutated candidate ligand residues in the recombinant enzyme and identified Glu,
His and Asp residues that are important for catalytic activity and/or stability
of the protein. However, neither of the Glu and His residues close to the HEXXH
motif that have previously been suggested to be ligands is required for the
binding of zinc. We conclude that thimet oligopeptidase is not a member of clan
MA or clan MB and it is likely that the enzyme possesses a catalytic site and
protein fold different from those identified in any metallopeptidase to date. The
definitive identification of the third zinc ligand may well require the
determination of the crystallographic structure of thimet oligopeptidase or one
of its homologues.
PMID- 9755849
TI - Molecular cloning and characterization of RBCK2, a splicing variant of a RBCC
family protein, RBCK1.
AB - RBCK1 (RBCC protein interacting with PKC 1) has two coiled-coil regions, a RING
finger, a B-box and a B-box-like motif. RBCK2, a cDNA fragment related to RBCK1
was obtained, that lacks the 161-bp sequence of RBCK1 and encodes 260 amino acid
residues. The 240-amino acid sequence in the NH2-terminal of RBCK2 is identical
with RBCK1 and contains two coiled-coil regions but no other structural motifs,
whereas the 20-amino acid sequence in the COOH-terminal is distinct from RBCK1.
The analysis of genomic DNA revealed that RBCK1 and RBCK2 are generated from a
single gene by alternative splicing. The RBCK1 protein interacted with the RBCK1
and RBCK2 proteins, but the RBCK2 protein did not interact with itself, in vitro.
The RBCK2 protein fused with the DNA-binding domain of yeast GAL4 (GAL4DBD) did
not show a transcriptional activity, but the RBCK2 protein inhibited the
transcriptional activity of the RBCK1 protein fused with GAL4DBD. These results
suggest that RBCK2 may inhibit the transcriptional activity of RBCK1 probably
through complex formation with RBCK1.
PMID- 9755851
TI - Anisoosmotic regulation of the Mi-2 autoantigen mRNA in H4IIE rat hepatoma cells
and primary hepatocytes.
AB - Using the differential display polymerase chain reaction (DDRT-PCR) a 169 bp cDNA
product, which is 88.8% homologous to the human Mi-2beta autoantigen, was
identified in H4IIE rat hepatoma cells. At protein level 100% homology was found.
The Mi-2 mRNA was downregulated after hypoosmotic exposure and upregulated after
hyperosmotic exposure in H4IIE cells and rat hepatocytes. The human Mi-2 is an
autoantigen in dermatomyositis and is a member of the SNF/RAD 54 helicase family.
Accordingly, Mi-2 may not only be a target of osmosignalling but could also be
involved in the osmosignalling pathway towards gene expression in H4IIE and liver
parenchymal cells.
PMID- 9755852
TI - Glucocorticoids decrease cytochrome c oxidase activity of isolated rat kidney
mitochondria.
AB - The importance of mitochondria is rising as a target in pathologic processes such
as ischemia. We have investigated the effects of hydrocortisone, prednisolone,
dexamethasone and triamcinolone on oxidative phosphorylation, Ca2+ fluxes,
swelling and membrane potentials in isolated kidney mitochondria. The measurement
of respiration state 3 showed a significant decrease in presence of
glucocorticoids whereas the other respiration states were not modified. When
mitochondria were uncoupled and either the complexes III and IV or the complex IV
were stimulated, the O2 consumption was decreased by glucocorticoids. These
results suggest the cytochrome c oxidase is a target of the glucocorticoid effect
on the respiratory chain. Indeed, the other mitochondrial functions investigated
were unchanged, ruling out a direct effect on Ca2+ fluxes or swelling. A
regulation of cytochrome c oxidase activity by glucocorticoids will be of
particular interest in pathology involving metabolic insult.
PMID- 9755853
TI - Synergistic upregulation of metalloproteinase-9 by growth factors and
inflammatory cytokines: an absolute requirement for transcription factor NF-kappa
B.
AB - Matrix metalloproteinase (MMPs) enzymes are implicated in matrix remodelling
during proliferative inflammatory processes including wound healing. We report
here synergistic upregulation of MMP-9 protein and mRNA by platelet-derived
growth factor (PDGF) or basic fibroblast growth factor (bFGF) in combination with
interleukin-1alpha (IL-1alpha) or tumour necrosis factor-alpha (TNF-alpha) in
primary rabbit and human dermal fibroblasts. The synergistic interaction between
growth factors and cytokines implies that basement membrane remodelling is
maximal physiologically when both are present together. The signalling pathways
mediating this synergistic regulation are not understood, although analysis of
the MMP-9 promoter has identified an essential proximal AP-1 element and an
upstream nuclear factor kappa-B (NF-kappaB) site. Using electromobility shift
assays, binding to the AP-1 site was only slightly increased by growth factors
and cytokines. NF-kappaB binding was rapidly induced by IL-1alpha or TNF-alpha
but was neither induced nor potentiated by bFGF or PDGF. Neither AP-1 nor NF
kappaB was therefore sufficient on its own for synergistic regulation. Using a
recently developed adenovirus that overexpresses the inhibitory subunit, IkappaB
alpha, we demonstrated an absolute requirement for NF-kappaB in upregulation of
MMP-9. Activation of NF-kappaB binding by inflammatory cytokines was therefore
necessary but not sufficient for synergistic upregulation of MMP-9.
PMID- 9755854
TI - Potentiation of nitric oxide synthase expression by superoxide in interleukin 1
beta-stimulated rat mesangial cells.
AB - Exposure of mesangial cells to superoxide, generated by the hypoxanthine/xanthine
oxidase system or by the redox cycler 2,3-dimethoxy-1,4-naphthoquinone caused a
concentration-dependent amplification of interleukin (IL)-1beta-stimulated
nitrite production. The effect of superoxide was accompanied by an increase in
inducible nitric oxide synthase (iNOS) protein and iNOS mRNA levels. Incubation
of mesangial cells with superoxide alone did not induce iNOS expression. To
elucidate whether the increase of iNOS expression is due to transcriptional
upregulation we fused a 4.5-kb genomic iNOS fragment that contains the
transcriptional start site of the rat iNOS gene to a luciferase reporter gene. In
transient transfection studies, superoxide caused a 10-fold augmentation of iNOS
promoter activity in IL-1beta-challenged mesangial cells. Our data identify
superoxide as a co-stimulatory factor amplifying cytokine-induced iNOS gene
expression and subsequent nitric oxide (NO) synthesis.
PMID- 9755855
TI - TNF-alpha converting enzyme (TACE) is inhibited by TIMP-3.
AB - TNF-alpha converting enzyme (TACE; ADAM-17) is a membrane-bound disintegrin
metalloproteinase that processes the membrane-associated cytokine proTNF-alpha to
a soluble form. Because of its putative involvement in inflammatory diseases,
TACE represents a significant target for the design of specific synthetic
inhibitors as therapeutic agents. In order to study its inhibition by tissue
inhibitors of metalloproteinases (TIMPs) and synthetic inhibitors of
metalloproteinases, the catalytic domain of mouse TACE (rTACE) was overexpressed
as a soluble Ig fusion protein from NS0 cells. rTACE was found to be well
inhibited by peptide hydroxamate inhibitors as well as by TIMP-3 but not by TIMP
1, -2 and -4. These results suggest that TIMP-3, unlike the other TIMPs, may be
important in the modulation of pathological events in which TNF-alpha secretion
is involved.
PMID- 9755856
TI - Cleavage and activation of proteinase-activated receptor-2 on human neutrophils
by gingipain-R from Porphyromonas gingivalis.
AB - Gingipain-R, the major arginine-specific proteinase from Porphyromonas
gingivalis, a causative agent of adult periodontal disease, was found to cleave a
model peptide representing the cleavage site of proteinase-activated receptor-2
(PAR-2), a G-protein-coupled receptor found on the surface of neutrophils. The
bacterial proteinase was also shown to induce an increase in the intracellular
calcium concentration of enzyme-treated neutrophils, most probably due to PAR-2
activation. This response by neutrophils to gingipain-R may be a mechanism for
the development of inflammation associated with periodontal disease.
PMID- 9755857
TI - Isolation and characterization of the Candida albicans gene for mRNA 5'
triphosphatase: association of mRNA 5'-triphosphatase and mRNA 5'
guanylyltransferase activities is essential for the function of mRNA 5'-capping
enzyme in vivo.
AB - The amino acid sequence of the Saccharomyces cerevisiae mRNA 5'-triphosphatase
(TPase) diverges from those of higher eukaryotes. In order to confirm the
sequence divergence of TPases in lower and higher eukaryotes, the Candida
albicans gene for TPase was identified and characterized. This gene designated
CaCET1 (C. albicans mRNA 5'-capping enzyme triphosphatase 1) has an open reading
frame of 1.5 kb, which can encode a 59-kDa protein. Although the N-terminal one
fifth of S. cerevisiae TPase (ScCet1p) is missing in CaCet1p, CaCet1p shares
significant sequence similarity with ScCet1p over the entire region of the
protein; the recombinant CaCet1p, which was expressed as a fusion protein with
glutathione S-transferase (GST), displayed TPase activity in vitro. CaCET1
rescued CET1-deficient S. cerevisiae cells when expressed under the control of
the ADH1 promoter, whereas the human capping enzyme derivatives that are active
for TPase activity but defective in mRNA 5'-guanylyltransferase (GTase) activity
did not. Yeast two-hybrid analysis revealed that C. albicans Cet1p can bind to
the S. cerevisiae GTase in addition to its own partner, the C. albicans GTase. In
contrast, neither the full-length human capping enzyme nor its TPase domain
interacted with the yeast GTase. These results indicate that the failure of the
human TPase activity to complement an S. cerevisiae cet1delta null mutation is
attributable, at least in part, to the inability of the human capping enzyme to
associate with the yeast GTase, and that the physical association of GTase and
TPase is essential for the function of the capping enzyme in vivo.
PMID- 9755858
TI - SKAP-HOM, a novel adaptor protein homologous to the FYN-associated protein
SKAP55.
AB - A recombinant GST-Fyn-SH2 domain was used to purify proteins from lysates of
pervanadate treated EL4 cells. N-terminal sequencing and molecular cloning of one
of the purified polypeptides resulted in the identification of a novel adaptor
protein that shares strong structural homology to the recently cloned Fyn
associated adaptor protein SKAP55. This protein was termed SKAP-HOM (SKAP55
homologue). Despite their striking homology, SKAP55 and SKAP-HOM have distinct
characteristics. Thus, unlike SKAP55, which is exclusively expressed in T
lymphocytes, SKAP-HOM expression is ubiquitous. Furthermore, while SKAP55 is
constitutively tyrosine phosphorylated in resting human T cells, SKAP-HOM is
expressed as a non-phosphorylated protein in the absence of external stimulus but
becomes phosphorylated following T cell activation. In addition, SKAP-HOM does
not associate with p59fyn in T cells although it represents a specific substrate
for the kinase in COS cells. Finally, we demonstrate that, as previously shown
for SKAP55, SKAP-HOM interacts with the recently identified polypeptide SLAP-130.
PMID- 9755859
TI - Type A botulinum neurotoxin proteolytic activity: development of competitive
inhibitors and implications for substrate specificity at the S1' binding subsite.
AB - Type A botulinum neurotoxin (botox A) is a zinc metalloprotease that cleaves only
one peptide bond in the synaptosomal protein, SNAP-25. Single-residue changes in
a 17-residue substrate peptide were used to develop the first specific,
competitive inhibitors of its proteolytic activity. Substrate analog peptides
with P4, P3, P2' or P3' cysteine were readily hydrolyzed by the toxin, but those
with P1 or P2 cysteine were not cleaved and were inhibitors. Peptides with either
D- or L-cysteine as the N-terminus, followed by the last six residues of the
substrate, were the most effective inhibitors, each with a Ki value of 2 microM.
Elimination of the cysteine sulfhydryl group yielded much less effective
inhibitors, suggesting that inhibition was primarily due to binding of the active
site zinc by the sulfhydryl group. Botox A displayed an unusual requirement for
arginine as the P1' inhibitor residue, demonstrating that the S1' binding subsite
of botox A is dissimilar to those of most other zinc metalloproteases. This
characteristic is an important element in shaping the substrate specificity of
botox A.
PMID- 9755860
TI - Identification and differential regional expression of KOR-3/ORL-1 gene splice
variants in mouse brain.
AB - KOR-3, also known as ORL-1, is a member of the opioid receptor family, encoding
the murine receptor for orphanin FQ/nociceptin. In the current studies we have
identified five different splice variants of KOR-3 in mouse brain, three of which
have not been previously reported. In addition to variants with a 15 bp deletion
at the 3'-end of the first coding exon (KOR-3d) and an 81 bp insertion between
the second and third coding exons (KOR-3e), three new variants with insertions of
34 (KOR-3a), 98 (KOR-3b), and 139 bp (KOR-3c) between the first and second coding
exons have been obtained. The expression of the three variants in mouse brain
varies markedly among brain regions with a distribution which is quite distinct
from KOR-3 itself. Of greatest interest was the presence of high levels of KOR-3a
in the striatum, a region with no demonstrable KOR-3, and in the cortex. KOR-3c
was seen in the periaqueductal gray and hypothalamus, regions where KOR-3
predominated. The brainstem had similar levels of KOR-3, KOR-3a, and KOR-3d. In
contrast, KOR-3d was most prominent in the cerebellum. KOR-3b levels were very
low throughout.
PMID- 9755861
TI - Probing pore topology and conformational changes of Kir2.1 potassium channels by
cysteine scanning mutagenesis.
AB - Using cysteine (Cys) scanning mutagenesis of the inward rectifier K+ channel
Kir2.1, we investigated its pore structure and putative conformational changes.
In the background of the Kir2.1 mutant C149F which showed no sensitivity towards
Cys-modifying reagents, Cys residues were introduced at 10 positions in the H5
pore region. Out of six functional mutants, T141C and F147C showed clear changes
in current amplitude when Cys-modifying reagents were applied from the external
side. These results suggest that the corresponding sections of the H5 pore region
face to the external side which is in contrast to the results previously obtained
for voltage-gated K+ (Kv) channels. Using the mutants T141C and F147C, we
investigated whether or not Kir2.1 channels show state-dependent conformational
changes of the pore structure. Substantial alterations of the holding potential
or external K+ concentration, however, did not cause any significant change in
the speed of channel modification upon application of Cys-specific reagents,
suggesting that Kir2.1 channels do not undergo conformational changes, in
contrast to C-type inactivating Kv channels.
PMID- 9755862
TI - Following G-quartet formation by UV-spectroscopy.
AB - Oligodeoxynucleotides which include stretches of guanines form a well-known
tetrameric structure. We show that the recording of reversible absorbance changes
at 295 nm allows to precisely monitor intramolecular guanine (G)-quartet
formation and dissociation. Accurate Tm and thermodynamic values could be easily
extracted from the data, whereas classical recordings at 260 nm led to a much
larger uncertainty and in extreme cases, to completely inaccurate measurements.
This inverted denaturation profile was observed for all G-quartet-forming
oligonucleotides studied so far. This technique is very useful in all cases where
intramolecular or intermolecular quadruplex formation is suspected.
PMID- 9755863
TI - Poliovirus 2A proteinase cleaves directly the eIF-4G subunit of eIF-4F complex.
AB - The initiation of translation on eukaryotic mRNA is governed by the concerted
action of polypeptides of the eIF-4F complex. One of these polypeptides, eIF-4G,
is proteolytically inactivated upon infection with several members of the
Picornaviridae family. This cleavage occurs by the action of virus-encoded
proteinases: 2Apro (entero- and rhinovirus) or Lpro (aphthovirus). An indirect
mode of eIF-4G cleavage through the activation of a second cellular proteinase
has been proposed in the case of poliovirus. Although cleavage of eIF4G by rhino-
and coxsackievirus 2Apro has been achieved directly in vitro, a similar activity
has not been documented to date for poliovirus 2Apro. We report here that a
recombinant form of poliovirus 2Apro fused to maltose binding protein (MBP)
directly cleaves human eIF-4G from a highly purified eIF-4F complex. Efficient
cleavage of eIF-4G requires magnesium ions. The presence of other initiation
factors such as eIF-3, eIF-4A or eIF-4B mimics in part the stimulatory effect of
magnesium ions and probably stabilizes the cleavage products of eIF-4G generated
by 2Apro. These results suggest that efficient cleavage of eIF4G by MBP-2Apro
requires a proper conformation of this factor. Finally, MBP-2Apro protein cleaves
an eIF-4G-derived synthetic peptide at the same site as rhino- and coxsackievirus
2Apro (R485-G486).
PMID- 9755864
TI - The 26-mer peptide released from SNAP-25 cleavage by botulinum neurotoxin E
inhibits vesicle docking.
AB - Botulinum neurotoxin E (BoNT E) cleaves SNAP-25 at the C-terminal domain
releasing a 26-mer peptide. This peptide product may act as an excitation
secretion uncoupling peptide (ESUP) to inhibit vesicle fusion and thus contribute
to the efficacy of BoNT E in disabling neurosecretion. We have addressed this
question using a synthetic 26-mer peptide which mimics the amino acid sequence of
the naturally released peptide, and is hereafter denoted as ESUP E. This
synthetic peptide is a potent inhibitor of Ca2+-evoked exocytosis in
permeabilized chromaffin cells and reduces neurotransmitter release from
identified cholinergic synapses in in vitro buccal ganglia of Aplysia
californica. In chromaffin cells, both ESUP E and BoNT E abrogate the slow
component of secretion without affecting the fast, Ca2+-mediated fusion event.
Analysis of immunoprecipitates of the synaptic ternary complex involving SNAP-25,
VAMP and syntaxin demonstrates that ESUP E interferes with the assembly of the
docking complex. Thus, the efficacy of BoNTs as inhibitors of neurosecretion may
arise from the synergistic action of cleaving the substrate and releasing peptide
products that disable the fusion process by blocking specific steps of the
exocytotic cascade.
PMID- 9755865
TI - Gos1p, a Saccharomyces cerevisiae SNARE protein involved in Golgi transport.
AB - Specific transport between secretory compartments requires that vesicular
carriers contain targeting proteins known as SNAREs. Ten v-SNAREs have been
identified in the genome of the yeast Saccharomyces cerevisiae by sequence
analysis. We report here the characterization of Gos1p, a v-SNARE localized to
the Golgi compartment and likely homolog of the mammalian protein GOS-28/GS28.
Gos1p is a type II membrane protein with characteristic SNARE sequence hallmarks
and is functionally a SNARE protein. Gos1p was originally identified as a 28 kDa
protein in an immunoprecipitate of the cis-Golgi t-SNARE Sed5p. This interaction
between Sed5p and Gos1p is direct as demonstrated by in vitro binding with
recombinant proteins. Deletion of GOS1 results in viable haploids with modest
growth and secretory defects. Close examination of the secretory phenotype of
GOS1-disrupted cells suggests that Gos1p may play a role in multiple transport
steps, specifically ER-Golgi and/or intra-Golgi transport.
PMID- 9755867
TI - Truncated recombinant light harvesting complex II proteins are substrates for a
protein kinase associated with photosystem II core complexes.
AB - Previous studies directed towards understanding phosphorylation of the
chlorophyll alb binding proteins comprising light harvesting complex II (LHC II)
have concentrated on a single phosphorylation site located close to the N
terminus of the mature proteins. Here we show that a series of recombinant pea
Lhcb1 proteins, each missing an N-terminal segment including this site, are
nevertheless phosphorylated by a protein kinase associated with a photosystem II
core complex preparation. An Lhch1 protein missing the first 58 amino acid
residues is not, however, phosphorylated. The results demonstrate that the LHC II
proteins are phosphorylated at one or more sites, the implications of which are
discussed.
PMID- 9755866
TI - Agonist stimulation of B1 and B2 kinin receptors causes activation of the MAP
kinase signaling pathway, resulting in the translocation of AP-1 in HEK 293
cells.
AB - In response to bradykinin, phosphorylated MAP kinases (ERK-1 and ERK-2) were
abundantly increased in HEK 293 cells, which overexpress the rat B2 kinin
receptor. In a similar way des-Arg9-bradykinin stimulation of B1 kinin receptor
overexpressing HEK 293 cells caused activation of the same species of MAP kinase.
Furthermore, nuclear translocation of transcription factor AP-1 was also found in
the cells after stimulation with either agonist. PD98059, a MAP kinase kinase
(MEK-1) inhibitor, blocked the agonist-induced AP-1 translocation as well as the
phosphorylation of the MAP kinases. This communication provides the first
evidence for both B1 and B2 kinin receptors mediating the MAP kinase signaling
pathway to activate AP-1.
PMID- 9755868
TI - Phosphorylation of the translational regulator, PHAS-I, by protein kinase CK2.
AB - The primary site in PHAS-I for phosphorylation by protein kinase CK2 in vitro was
identified as Ser111. A relatively small amount of phosphorylation of Ser99 was
also detected, and mutating Ser99 to Ala in PHAS-I slightly decreased
phosphorylation by CK2 in vitro. In contrast, mutating Ser111 to Ala almost
abolished phosphorylation, confirming Ser111 as the preferred site for CK2.
Phosphorylation of Ser111 did not decrease binding of PHAS-I to eIF4E, and
results of peptide mapping experiments with PHAS-I immunoprecipitated from 32P
labeled adipocytes indicated that Ser111 was not phosphorylated in cells. These
results support the conclusion that CK2 is not involved in the control of PHAS-I.
PMID- 9755869
TI - Site-specific regulatory interaction between spinach leaf sucrose-phosphate
synthase and 14-3-3 proteins.
AB - We report an Mg2+-dependent interaction between spinach leaf sucrose-phosphate
synthase (SPS) and endogenous 14-3-3 proteins, as evidenced by co-elution during
gel filtration and co-immunoprecipitation. The content of 14-3-3s associated with
an SPS immunoprecipitate was inversely related to activity, and was specifically
reduced when tissue was pretreated with 5-aminoimidazole-4-carboxamide riboside,
suggesting metabolite control in vivo. A synthetic phosphopeptide based on Ser
229 was shown by surface plasmon resonance to bind a recombinant plant 14-3-3,
and addition of the phosphorylated SPS-229 peptide was found to stimulate the SPS
activity of an SPS:14-3-3 complex. Taken together, the results suggest a
regulatory interaction of 14-3-3 proteins with Ser-229 of SPS.
PMID- 9755870
TI - Concomitant activation of Gi and Gq protein-coupled receptors does not require an
increase in cytosolic calcium for platelet aggregation.
AB - U46619 is a potent platelet agonist, its binding to the thromboxane A2 receptor
resulting in Gq-binding protein-mediated responses; nevertheless, it is unable to
cause platelet aggregation, unless released ADP is present. In this study we
demonstrate that Gi activation is the step U46619 lacks to cause platelet
aggregation; in fact, when platelets were treated with an ADP scavenger system,
the response to U46619 was restored by the addition of epinephrine, which
activates platelets via a Gi protein. The concomitant activation of Gi and Gq
proteins does not require increased cytosolic calcium to cause aggregation, as
assessed by the fact that platelets treated with the intracellular calcium
chelator BAPTA were able to respond to U46619 provided ADP or epinephrine was
present. Moreover, as the calcium ionophore ionomycin, at low concentrations,
potentiated the response to U46619 but not to epinephrine, we may conclude that
calcium influx preferentially activates a Gi downstream signalling pathway.
PMID- 9755871
TI - The expression of epidermal growth factor and transforming growth factor-alpha
mRNA in the small intestine of suckling rats: organ culture study.
AB - Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha)
are associated with regulation of various gastrointestinal functions. In order to
better understand their role in developing small intestine EGF, TGF-alpha and EGF
R steady-state mRNA levels and transcript stability were determined. Reverse
transcription (RT) competitive-polymerase chain reaction (PCR) revealed that
intestinal TGF-alpha mRNA levels were 10-fold higher in comparison with EGF mRNA.
The primary intestinal culture technique was used to evaluate mRNA stability. The
stability of TGF-alpha mRNA was remarkably lower than the stability of EGF mRNA.
High levels of TGF-alpha mRNA accompanied by high degradation rate of this mRNA
suggested a rapid turnover of intestinal TGF-alpha mRNA.
PMID- 9755872
TI - Dephosphorylation of perilipin by protein phosphatases present in rat adipocytes.
AB - By incubating 32P-labelled adipocytes, and extracts from these cells, in the
presence or absence of specific inhibitors, we evaluated the contribution of
protein phosphatases PP1, PP2A and PP2C, to the dephosphorylation of perilipin,
an acutely hormone-regulated adipocyte phosphoprotein. Under conditions to
completely inhibit PP2A activity, perilipin phosphatase activity in extracts
remain unaffected, but PP1 inhibition results in abolition of perilipin
phosphatase activity. Inhibition of PP1 (and 2A) in intact adipocytes stimulated
lipolysis and increased phosphorylation of perilipin. No involvement of PP2C was
found. Hence, PP1 constitutes the predominant if not sole perilipin phosphatase
in adipocytes.
PMID- 9755873
TI - Immunopotentiation with low-dose cyclophosphamide in the active specific
immunotherapy of cancer.
AB - This paper reviews the use of low-dose cyclophosphamide (CY) with active specific
immunotherapy in patients with advanced melanoma and other metastatic cancers,
and outlines the basic scientific research that supports this use. In various
animal models, CY augments delayed-type hypersensitivity responses, increases
antibody production, abrogates tolerance, and potentiates antitumor immunity. The
mechanism of CY immunopotentiation involves inhibition of a suppressor function,
as indicated by extensive work in the MOPC-315 plasmacytoma murine model. Human
studies of the immunopotentiating effect of CY have yielded both positive and
negative results. Toxicity associated with low-dose CY has been mild in these
studies. Results of efficacy have been variable for reasons such as small sample
sizes, short follow-up periods, and the weaker immunogenicity of human tumor
associated antigens. Although beneficial clinical outcomes have been observed in
historically controlled trials, there are few randomized, controlled trials that
evaluate outcome in relation to CY immunopotentiation of active specific
immunotherapy. Additional randomized, controlled trials should be done to examine
the clinical efficacy of CY immunopotentiation of therapeutic cancer vaccines.
PMID- 9755874
TI - Induction of anti-idiotypic humoral and cellular immune responses by a murine
monoclonal antibody recognizing the ovarian carcinoma antigen CA125 encapsulated
in biodegradable microspheres.
AB - The use of biodegradable poly(DL-lactic-co-glycolic acid) microspheres as a
cancer vaccine delivery system for induction of anti-idiotypic responses was
investigated using a murine monoclonal antibody B43.13 that recognizes the human
ovarian cancer antigen CA125. Immunization of mice with mAb B43.13 encapsulated
in poly(DL-lactic-co-glycolic acid) microspheres resulted in enhanced humoral and
cellular immune responses compared with mAb B43.13 alone or mAb B43.13 mixed with
microspheres. The antibody responses could be further enhanced by the co
encapsulation of mAb B43.13 with monophosphoryl lipid A, a non-toxic adjuvant, in
microspheres. Anti-idiotypic humoral responses were shown to result in Ab2
antibodies mimicking the nominal antigen CA125 and Ab3 antibodies recognizing
CA125. Further, microsphere delivery of mAb B43.13 also resulted in induction of
T cell responses involving T2 cells reactive with mAb B43.13 epitopes and T3
cells recognizing CA125. These results indicate that microsphere delivery of Abl
can induce both humoral and cellular anti-idiotypic responses relevant to cancer
antigens. This raises the possibility of the use of such formulations for anti
idiotypic induction immunotherapy for cancer.
PMID- 9755875
TI - Induction of HLA-unrestricted and HLA-class-II-restricted cytotoxic T lymphocytes
against MUC-1 from patients with colorectal carcinomas using recombinant MUC-1
vaccinia virus.
AB - We recently reported that immunization with a recombinant MUC-1 vaccinia virus
(rVMUC-1) protected C57BL/6 mice from challenge with DF3/MUC-1-positive syngeneic
tumors. To elucidate whether anti-MUC-1 tumor immunity, especially MUC-1-specific
cytotoxic T lymphocytes (CTI), can be induced in cancer patients by rVMUC-1, we
stimulated the peripheral blood lymphocytes from patients with DF3/MUC-1+ or
DF3/MUC-1 colon carcinomas using the autologous monocytes infected with rVMUC-1
(rVAMN). The stimulated T lymphocytes from two patients with DF3/MUC-1-positive
colorectal carcinomas (rVPY+T and rVPW+T) demonstrated HLA-unrestricted
cytotoxicity against MUC-1, whereas those from the patient with DF3/MUC-1
negative colon carcinoma (rVPA-T) did not. The HLA-unrestricted cytotoxicity was
demonstrated by the CD8+ T cells possibly recognizing an epitope present on the
tandem repeats. Adoptive immunotherapy who performed three times with patient PY,
at 4-week intervals. The adoptive transfer of the first stimulated lymphocytes,
demonstrating a high level of HLA-unrestricted cytotoxicity against MUC-1,
resulted in the significant reduction of the liver metastasis of patient PY.
However, HLA-unrestricted cytotoxicity against MUC-1 was extremely reduced at the
second transfer and finally eliminated at the third, whereas the CD4+ T cells
demonstrating HLA-class-II-restricted cytotoxicity against MUC-1 predominantly
proliferated at the third adoptive immunotherapy treatment. The liver metastasis
and the serum levels of tumor markers (carcinoembryonic antigen CA19-9)
demonstrated a rapid and marked increment after the second transfer and
especially after the third. These results suggest that the HLA-unrestricted
cytotoxic CD8+ T cells against MUC-1, induced in patients with DF3/MUC-1+
colorectal carcinomas using rVMUC-1, correlate with the antitumor activity in
vivo.
PMID- 9755876
TI - Tumour-specific MHC-class-II-restricted responses after in vitro sensitization to
synthetic peptides corresponding to gp100 and Annexin II eluted from melanoma
cells.
AB - In a search for potentially tumour-specific MHC-class-II-restricted antigens, the
immunogenicity of endogenous peptides that had been eluted from HLA-DR molecules
of the human melanoma cell line FM3 (HLA-DRB1*02x, DRB1*0401) was tested in
vitro. Two 16-mers representing gp100 positions 44-59, and annexin II positions
208-223 bound well to isolated DRB1*0401 molecules and are discussed here. HLA-DR
matched normal donors' T cells were cultured with peptide-pulsed artificial
antigen-presenting cells (CHO cells cotransfected with genes for HLA-DRB1*0401
and CD80 and coexpressing high levels of both human molecules). Specific
sensitization was achieved against both peptides, as measured in assays of
autocrine proliferation and interleukin-2 secretion. Moreover, responses to
native autologous melanoma cells but not to autologous B cells were also
observed. In view of the expression of fas by the activated T cells and of fas
ligand by the melanoma cells, blockade of potential fas/ fas-ligand interactions
was undertaken using monoclonal antibodies (mAb). The antagonistic fas-specific
mAb M3, but not the fas agonist M33, caused a markedly enhanced T cell response
to FM3 cells. These results demonstrate that synthetic peptide antigens are able
to sensitize T cells in vitro for effective MHC-class-II-restricted recognition
of melanoma cells.
PMID- 9755877
TI - Biodistribution of 111In-labelled engineered human antibody CTM01 (hCTM01) in
ovarian cancer patients: influence of prior administration of unlabelled hCTM01.
AB - mAb hCTM01 binds a carcinoma-associated antigen, the MUC1 gene product. The
antigen is also present in the circulation, and administration of 111In-labelled
hCTM01 results in the formation of immune complexes with enhanced accumulation in
the liver. To avoid the unwanted effect of circulating radioactive immune
complexes, a strategy to remove the circulating antigen was investigated using a
split-dosage schedule. Eleven patients suspected of having ovarian carcinoma were
injected with 1 mg/kg unlabelled hCTM01, 1 h before receiving 0.1 mg/kg 111In
labelled hCTM01 (100 M Bq). The amount of radioactivity was determined in
resected tumour tissue, various normal tissues and blood samples obtained at
laparotomy 6 days postinjection (p.i.). In all patients, the circulating antigen
decreased to its nadir after the unlabelled antibody infusion and immune complex
formation was demonstrated. Uptake in tumour deposits 6 days p.i. was 11.1 times
higher than in normal tissues (P < 0.0001) and 5.9 times higher than in blood (P
< 0.0001). 111In activity in liver tissue was comparable to 111In uptake in
tumour tissue, and considerably lower than previously reported in patients not
pretreated with unlabelled antibody. The split-dosing strategy would appear to be
advantageous for use of hCTM01 as a specific carrier for the delivery of
cytotoxic agents to patients with ovarian cancer.
PMID- 9755878
TI - Effect of interleukin-8 on production of tumor-associated substances and
autocrine growth of human liver and pancreatic cancer cells.
AB - We have previously reported that human liver cancer cell lines produce
interleukin-8 (IL-8) at high levels. Those tumor cells appeared to express two
kinds of IL-8 receptor on their surface. In order to analyze the role of IL-8 on
the biological characteristics of those tumor cells, we suppressed IL-8
production from human liver (HuH-7 and HuCC-T1) and pancreatic cancer cell lines
(HuP-T4) by treatment with IL-8 antisense oligonucleotides. Suppression of IL-8
production resulted not only in inhibition of cell growth, but also in an
increase in the concentrations of some tumor-associated substances such as
carbohydrate antigen 19-9 (CA19-9) in the medium. These data indicate that IL-8
produced by human liver and pancreatic tumors may act as an autocrine growth
factor and may control the production of some tumor-associated substances.
Furthermore, surface expression of sialyl-Lewis(a), which is a ligand for ELAM-1
on human umbilical vein endothelial cells (HUVEC), HuCC-T1 and HuP-T4 cells was
decreased and the attachment of these tumor cells to HUVEC was inhibited by
treatment with IL-8 antisense oligonucleotide. Since the soluble form of CA19-9
(sialyl-Lewis(a)) was shown to inhibit the tumor cell binding to HUVEC, the
decrease in release of CA19-9 into the medium and increase in the expression of
sialyl-Lewis(a) on the cell surface may suggest that IL-8 production from the
tumor cells enhances metastatic potential by augmenting the binding activity of
the tumor cells to HUVEC. These data demonstrate that a cytokine produced by
tumor cells may function as an autocrine growth factor and affect tumor cell
dissemination.
PMID- 9755879
TI - Immunization with a tumor-cell-lysate-loaded autologous-antigen-presenting-cell
based vaccine in melanoma.
AB - The discoveries of human melanoma-associated antigens in molecular terms have
renewed interest in peptide- or peptide- and antigen-presenting-cell (APC)-based
cancer vaccines. Considering the limited scope of immunization using defined
peptides, we have studied an alternative approach of specific immunization with
tumor-lysate-loaded autologous APC (adherent peripheral mononuclear cells
cultured in 1000 U granulocyte/macrophage-colony-stimulating factor for 14 days)
as a surrogate vaccine. Seventeen patients (11 with active metastatic disease)
were intradermally immunized with the vaccine in a phased dose escalation (10(5)
10(7) cells/injection) monthly for 4 months. Thirteen patients completed all four
immunizations showing no toxicity (3 patients had to be taken off study because
of progressive disease and 1 patient went off study as a result of myocardial
infarction due to multi-vessel coronary artery disease). None has shown any
immediate or delayed toxicity attributable to the immunization and none has shown
any evidence of autoimmunity. One patient showed a partial regression of a
subcutaneous nodule. Thirteen patients are alive after 4+ months to 30+ months
(17-month median survival for the group). Nine patients showed evidence of
delayed-type hypersensitivity at the vaccine sites. Monitoring of biological
response in conventional natural killer or cytolytic T lymphocyte assays with pre
and post-immune peripheral blood lymphocytes revealed no consistent differences.
The vaccine-infiltrating lymphocytes (VIL) from nine specimens were adequately
expanded following in vitro stimulation with the respective autologous-lysate
loaded APC for phenotypic and functional analyses. Five of the nine ex vivo
expanded VIL were predominantly CD8+. Evidence of an antigen-specific CD8+ T cell
response (cytotoxicity and/or tumor necrosis factor production) was detected in
three of the five CD8+ VIL. These observations suggest that this type of vaccine
is feasible, that it has biological activity, and that the approach may be
improved through additional strategic manipulations.
PMID- 9755880
TI - Individual bioequivalence: attractive in principle, difficult in practice.
PMID- 9755881
TI - Chitosan and its use as a pharmaceutical excipient.
AB - Chitosan has been investigated as an excipient in the pharmaceutical industry, to
be used in direct tablet compression, as a tablet disintegrant, for the
production of controlled release solid dosage forms or for the improvement of
drug dissolution. Chitosan has, compared to traditional excipients, been shown to
have superior characteristics and especially flexibility in its use. Furthermore,
chitosan has been used for production of controlled release implant systems for
delivery of hormones over extended periods of time. Lately, the transmucosal
absorption promoting characteristics of chitosan has been exploited especially
for nasal and oral delivery of polar drugs to include peptides and proteins and
for vaccine delivery. These properties, together with the very safe toxicity
profile, makes chitosan an exciting and promising excipient for the
pharmaceutical industry for present and future applications.
PMID- 9755882
TI - Chitosan-based vector/DNA complexes for gene delivery: biophysical
characteristics and transfection ability.
AB - PURPOSE: Chitosan, a natural cationic polysaccharide, is a candidate non-viral
vector for gene delivery. With the aim of developing this system, various
biophysical characteristics of chitosan-condensed DNA complexes were measured,
and transfections were performed. METHODS: Transmission electronic microscopy
(TEM) visualizations, sedimentation experiments, dynamic light scattering (DLS),
and zeta potential measurements were realized. Transfections were made by using
the luciferase reporter gene. RESULTS: In defined conditions, plasmid DNA
formulated with chitosan produced homogenous populations of complexes which were
stable and had a diameter of approximately 50-100 nm. Discrete particles of
nicely condensed DNA had a donut, rod, or even pretzel shape. Chitosan/DNA
complexes efficiently transfected HeLa cells, independently of the presence of
10% serum, and did not require an added endosomolytic agent. In addition, gene
expression gradually increased over time. from 24 to 96 hours, whereas in the
same conditions the efficacy of polyethylenimine-mediated transfection dropped by
two orders of magnitude. At 96 hours, chitosan was found to be 10 times more
efficient than PEI. However, chitosan-mediated transfection depended on the cell
type. This dependency is discussed here. CONCLUSIONS: Chitosan presents some
characteristics favorable for gene delivery, such as the ability to condense DNA
and form small discrete particles in defined conditions.
PMID- 9755883
TI - Target specific optimization of cationic lipid-based systems for pulmonary gene
therapy.
AB - PURPOSE: Cationic lipids are capable of transferring foreign genes to the
pulmonary epithelium in vivo. It is becoming increasingly clear that factors
other than lipid molecular structure also influence efficiency of delivery using
cationic lipid systems. This study is aimed at evaluating the effect of
formulation variables such as cationic lipid structure, cationic lipid/DNA ratio,
particle size, co-lipid content and plasmid topology on transgene expression in
the lung. METHODS: The effect of varying the surface and colloidal properties of
cationic lipid-based gene delivery systems was assessed by intratracheal
instillation into rats. An expression plasmid encoding chloramphenicol acetyl
transferase (CAT) was used to measure transgene expression. RESULTS: Cationic
lipid structure, cationic lipid/DNA ratio, particle size, co-lipid content and
topology of the plasmid, were found to significantly affect transgene expression.
Complexation with lipids was found to have a protective effect on DNA integrity
in bronchoalveolar lavage fluid (BALF). DNA complexed with lipid showed enhanced
persistence in rat lungs as measured by quantitative polymerase chain reaction.
CONCLUSIONS: Fluorescence microscopy analysis indicated that the instilled
formulation reaches the lower airways and alveolar region. Data also suggests
cationic lipid-mediated gene expression is primarily localized in the lung
parenchyma and not infiltrating cells isolated from the BALF.
PMID- 9755884
TI - Beta cyclodextrins enhance adenoviral-mediated gene delivery to the intestine.
AB - PURPOSE: In general, the intestinal epithelium is quite refractory to viral and
non-viral methods of gene transfer. In this report, various cyclodextrin
formulations were tested for their ability to enhance adenoviral transduction
efficiency in two models of the intestinal epithelium: differentiated Caco-2
cells and rat jejunum. METHODS: Transduction efficiency of replication-deficient
adenovirus type 5 vectors encoded with either the E. coli beta-galactosidase or
the jellyfish green fluorescent protein gene was assessed by X-gal staining or
visualization of fluorescence 48 hours after infection. In vivo experiments were
performed using an intestinal loop ligation technique. RESULTS: Several
formulations of neutral and positively charged beta cyclodextrins significantly
enhanced adenoviral-mediated gene transfer in the selected models. The
cyclodextrin formulations studied increased adenoviral transduction in the
intestine by enhancing both viral binding and internalization. Viral binding was
significantly increased on cell membranes treated with positively charged
cyclodextrins, as seen with confocal microscopy and rhodamine-labeled virus.
Permeability studies and TEER readings revealed that the most successful
formulations gently disrupt cell membranes. This enhances internalization of
viral particles and results in increased levels of gene expression. CONCLUSIONS:
These formulations can be of value in gene transfer to cells and tissues in which
adenoviral infection is limited due to a lack of fiber and alpha(v) integrin
receptors. They are simple to prepare and do not affect the ability of the virus
to transduce target cells.
PMID- 9755886
TI - Liposomes dispersed within a thermosensitive gel: a new dosage form for ocular
delivery of oligonucleotides.
AB - PURPOSE: The main goal of this study was to develop an ocular controlled release
formulation of a model oligonucleotide (pdT16), contained within liposomes
dispersed within a thermosensitive gel composed by poloxamer 407. METHODS: The
influence of the poloxamer concentration 2% or 27% on the stability of the
liposomes (PC: CHOL and PC: CHOL: PEG-DSPE) was investigated. The in vitro
release profiles of pdT16 from various poloxamer formulations (free pdT16
dispersed within 20% and 27% poloxamer gels, pdT16 encapsulated within liposomes
dispersed within 20% and 27% poloxamer gels) were realized using a membrane-free
release model. RESULTS: The dispersion of liposomes within a dilute 2% poloxamer
solution resulted in a great leakage of pdT16 from liposomes. However, the
destabilization effect of poloxamer was reduced when higher concentration (27%)
was used. Poloxamer dissolution was found to control the release process of
pdT16, whereas the dispersion of liposomes within 27% poloxamer gel was shown to
slow down the diffusion of pdT16 out from the gel. CONCLUSIONS: The dispersion of
liposomes within a 27% poloxamer gel presented an interesting system to control
the release of a model oligonucleotide compare to a simple gel.
PMID- 9755885
TI - Characterization and in vivo testing of a heterogeneous cationic lipid-DNA
formulation.
AB - PURPOSE: To identify characteristics of lipid-DNA complexes that correlate with
in vivo expression data. METHODS: DOTIM:cholesterol liposomes (1:1 mole ratio)
and DNA expressing chloramphenicol acetyl transferase (CAT) were complexed at a
4.2:1 mass ratio (cationic lipid:DNA). Complexes were fractionated by density
gradient centrifugation. analyzed for particle size and zeta potential and
quantitated using HPLC methods. The unfractionated complexes, "purified"
fractions of the complexes, and purified complexes supplemented with liposomes
were administered to mice by intravenous injection (i.v.) and intratracheal
instillation (i.t.) and their ability to express gene product was assessed.
RESULTS: Centrifugation separated two distinct populations within complexes one
consisting of free liposomes and the other of lipid complexed with DNA. The
vesicle diameter and zeta potential among separated fractions varied from 113 to
354 nm. and + 24 to + 34 mV respectively. Re-centrifugation of the 'purified'
fractions containing the lipid-DNA population produced a single band. CAT
expression in lung tissue 24 hr post-i.v. was observed with the unfractionated
complex, but not the purified form. Some activity was 'restored' with the
liposome-supplemented complexes. In contrast, the same series of complexes
administered by i.t. resulted in no significant difference in lung expression
(p=0.16 ANOVA). CONCLUSIONS: An uncomplexed liposome population exists within
DOTIM:cholesterol-DNA complexes that influences the expression of complexes
administered i.v. but not i.t..
PMID- 9755887
TI - Prediction of intestinal drug absorption properties by three-dimensional
solubility parameters.
AB - PURPOSE: The purpose of this study was to investigate the use of solubility
parameters for the prediction of gastrointestinal absorption sites and absorption
durations of drugs. METHODS: Three-dimensional solubility parameters of drug
substances were calculated using an advanced parameter set based on the group
contribution methods of Fedors and Van Krevelen/Hoftyzer. The results of the
calculations were illustrated via Bagley diagram and related to absorption data
reported in the literature. RESULTS: Solubility parameters of drugs which are
known to be absorbed over a long period in human's digestive tract were found in
a limited area within the Bagley diagram. From the three-dimensional solubility
parameters of these substances, a region for optimal absorption with the centre
coordinates delta(v)=20.3 (J x cm(-3))(0.5) and delta(h)=11.3 (J x cm(-3))(0.5)
could be derived. Drugs with absorption sites along the whole gastrointestinal
tract were found in this area. Drugs which are preferably absorbed from upper
parts of the intestine are located in another typical region with partial
solubility parameters delta(h) of more than 17 (J x cm(-3))(0.5). CONCLUSIONS:
The method which is presented in this paper appears as a simple but effective
method to estimate the absorption behaviour of new substances in drug research
and development.
PMID- 9755888
TI - Overexpression of human intestinal oligopeptide transporter in mammalian cells
via adenoviral transduction.
AB - PURPOSE: Our goals are to establish an in vitro screening system and to evaluate
a new approach in improving oral absorption of peptides and peptide-like drugs by
overexpression of the human intestinal oligopeptide transporter (hPepT1). This
study characterizes the expression of hPepT1 in human intestinal Caco-2 cells,
rat intestinal epithelial cells (IEC-18), and human cervix epithelial cells
(Hela) after adenoviral transduction. METHODS: A recombinant replication
deficient adenovirus carrying the hPepT1 gene was made and used as a vector for
the expression of hPepT1. The increase in the uptake permeability of cephalexin
and Gly-Sar was determined. The effects of time, dose, apical pH, and substrate
specificity were evaluated. RESULTS: A significant increase in the uptake
permeability of Gly-Sar and cephalexin was found in all three cell lines after
viral transduction. The increase of Gly-Sar permeability in Hela. IEC-18, and
Caco-2 cells was 85-, 46-, and 15-fold respectively. Immunoblotting using an
antibody against hPepT1 detected high levels of a 85-98-kDa protein in all three
infected cell lines. Substrate permeability was dependent on time of infection,
inward pH gradients, and multiplicity of infection (MOI). Decreased infectivity
and lower hPepT1 expression were observed in differentiated Caco-2 cells. The
uptake was inhibited by dipeptides and beta-lactam antibiotics but not amino
acids. CONCLUSIONS: Adenoviral infected Hela cells displayed a pronounced level
of hPepT1 expression with a low background and high specificity to dipeptides.
These features make this system a useful tool for screening of potential
substrates. The success of overexpression of hPepT1 in Caco-2 and IEC-18 cells
may lead to a novel approach in improving oral absorption of peptides and
peptidornimetic drugs.
PMID- 9755890
TI - Permeability characteristics of tetragastrins across intestinal membranes using
the Caco-2 monolayer system: comparison between acylation and application of
protease inhibitors.
AB - PURPOSE: Three types of acyl tetragastrin (TG), acetyl-TG (C2-TG), butyryl-TG (C4
TG) and caproyl-TG (C6-TG) were synthesized and their in vitro intestinal
permeability characteristics were examined using Caco-2 monolayers. METHODS: The
disappearance of acyl-TGs from the apical side of Caco-2 monolayers was estimated
by analyzing degradation and permeation processes in terms of clearance. RESULTS:
The amount of native TG transported to the basolateral side was very low due to
its large degradation clearance (CLd) on the apical side. Degradation of TG was
reduced by chemical modification with fatty acids, which resulted in an increase
in the transport of TG across Caco-2 monolayers. In addition, the permeation
clearance (CLp) value of carboxyfluorescein (CF), a paracellular transport and
undegradable marker, was increased in the presence of acyl-TGs. Furthermore, we
investigated the effects of the protease inhibitors bacitracin and gabexate on
the transport of TG across Caco-2 monolayers. In the presence of a low
concentration (0.1 mM) of protease inhibitor, the CLd value of TG was reduced,
but they did not affect its CLp value. However, a higher concentration (1.0 mM)
of bacitracin significantly reduced TG degradation on the apical side, and
further increased its CLp value. CONCLUSIONS: We demonstrated that acylation of
TG made it resistant to intestinal proteases and caused it to enhance absorption
of drugs, including itself, across Caco-2 monolayers. Further, bacitracin acted
as both a protease inhibitor and an absorption enhancer.
PMID- 9755889
TI - Cellular uptake mechanism of amino acid ester prodrugs in Caco-2/hPEPT1 cells
overexpressing a human peptide transporter.
AB - PURPOSE: This study characterized the cellular uptake mechanism and hydrolysis of
the amino acid ester prodrugs of nucleoside antiviral drugs in the transiently
transfected Caco-2 cells overexpressing a human intestinal peptide transporter,
hPEPT1 (Caco-2/hPEPT1 cells). METHODS: Amino acid ester prodrugs of acyclovir and
AZT were synthesized and their apical membrane permeability and hydrolysis were
evaluated in Caco-2/hPEPT1 cells. The cellular uptake mechanism of prodrugs was
investigated through the competitive inhibition study in Caco-2/hPEPT1 cells.
RESULTS: L-Valyl ester of acyclovir (L-Val-ACV) was approximately ten fold more
permeable across the apical membrane than acyclovir and four times more permeable
than D-valyl ester of acyclovir (D-Val-ACV). Correspondingly, L-valyl ester of
AZT (L- Val-AZT) exhibited three fold higher cellular uptake than AZT. Therefore,
amino acid ester prodrugs significantly increased the cellular uptake of the
parent drugs and exhibited the D,L-stereoselectivity. Furthermore, prodrugs were
rapidly hydrolyzed to the parent drugs by the intracellular hydrolysis, following
the apical membrane transport. In the inhibition studies, cephalexin and small
dipeptides strongly inhibited the cellular uptake of L-Val-ACV while L-valine had
no effect, indicating that the peptide transporter is primarily responsible for
the apical membrane transport of L-Val-ACV. In addition, the cellular uptake of L
Val-ACV was five times higher in Caco-2/hPEPT1 cells than the uptake in the
untransfected Caco-2 cells, implying the cellular uptake of L-Val-ACV was related
to the enhancement of the peptide transport activity in Caco-2/hPEPT1 cells.
CONCLUSIONS: Caco-2/hPEPT1 system is an efficient in vitro model for the uptake
study of peptidyl derivatives. Amino acid ester prodrugs significantly improved
the cellular uptake of the parent drugs via peptide transport mechanism and were
rapidly converted to the active parent drugs by the intracellular hydrolysis.
PMID- 9755891
TI - Transport of proteolytic enzymes across Caco-2 cell monolayers.
AB - PURPOSE: To investigate the mechanisms by which proteolytic enzymes, such as
trypsin, chymotrypsin, papain, and bromelain, are able to cross the intestinal
mucosal barrier after oral administration to man. METHODS: Filter-grown Caco-2
cell monolayers were incubated with proteolytic enzymes and then the
transepithelial electrical resistance (TEER) and the transport of the
paracellular marker fluorescein were monitored. The effects of the enzymes on the
cells were investigated by light microscopy and by biochemical assays. Transport
of intact proteases across the cells was verified by monitoring the proteolytic
activity and MALDI-TOF mass spectroscopic identification of undegraded trypsin.
RESULTS: Depending on time, concentration, and side of exposure to Caco-2 cell
monolayers, all proteases decreased the TEER and increased the transport of
fluorescein. Some morphological and metabolic changes were observed. The effects
were reversible, but until 24 hours after removal of the proteases. Under the
conditions of this in-vitro model, approximately 10% of the apically applied dose
reached the basolateral compartment as biologically active, non-degraded
molecules. CONCLUSIONS: Proteolytic enzymes were found to exert considerable
effects on the barrier function of Caco-2 monolayers, facilitating the transport
of normally non-absorbable compounds. This suggests the also reported, but so far
unexplained, systemic absorption of proteolytic enzymes after oral administration
in vivo may occur by self-enhanced paracellular transport.
PMID- 9755892
TI - Hydrophobicity of HIV protease inhibitors by immobilized artificial membrane
chromatography: application and significance to drug transport.
AB - PURPOSE: The feasibility of using hydrophobicity measurements as screens for
intracellular availability in T-cells or intestinal permeability in Caco-2 cells
was examined. METHODS: T-cell experiments: Cells were counted, collected, then
incubated with drug solution at 37 degrees C. At selected time intervals, uptake
was quenched by transferring a sample into oil, followed by rinsing, lysis of
cells, protein precipitation and analysis by HPLC. Caco-2 cell experiments: Cells
were grown on plastic dishes for 7-10 d, then rinsed and incubated with drug
solution at 37 degrees C. Uptake was quenched, cells were lysed, protein
precipitated and drug was analyzed by HPLC. IAM chromatography: Stock solutions
were injected onto an IAM column for HPLC. Mobile phase consisted of varying
amounts of acetonitrile in buffer (pH 7.4). The capacity factor, k'IAM, was
calculated using citric acid to measure the void volume and was obtained by
extrapolation to pure buffer. RESULTS: Nine HIV protease inhibitors were studied
for uptake by CEM T-cell suspensions or Caco-2 cell monolayers. Capacity factors
(log) between IAM and C-18 columns were positively correlated for this series.
Caco-2 uptake rates correlated well with T-cell uptake rates when normalized by
protein mass. Single-variable regression using IAM or C-18 columns was acceptable
for analysis of T-cell data. Correlation coefficients between T-cell uptake and
log k'IAM or log k'C-18 were not improved with multivariable regression.
Correlation between Caco-2 uptake and log k'IAM was enhanced when molecular
weight and hydrogen-bonding potential were included in multivariable regression
analysis (from r2 of 0.39 to 0.91). Correlations obtained using log k'IAM, log
k'C-18 or log distribution coefficient (log D) were comparable when regressed
against Caco-2 uptake using this approach. Calculated log partition coefficient
(ClogP) provided the poorest correlation in the multivariable analysis (r2=0.57
for T-cell uptake and r2=0.71 for Caco-2 cell uptake). CONCLUSIONS: Uptake of HIV
protease inhibitors by T-cell suspensions or Caco-2 cell monolayers was
positively correlated. Uptake by T-cell suspensions was adequately described by
hydrophobicity alone. Description of uptake by Caco-2 cell monolayers required
multivariable regression analysis in which molecular weight and hydrogen bonding
were included. Experimental measures of hydrophobicity (log k'IAM, log k'C-18 and
log D) were superior to ClogP in the correlation analysis.
PMID- 9755894
TI - Permeability of articular cartilage to matrix metalloprotease inhibitors.
AB - PURPOSE: To develop an in vitro cartilage permeation model for cartilage
permeability study and to evaluate the effects of molecular hydrophilicity and
cartilage location on the permeability of articular cartilage to matrix
metalloprotease inhibitors. METHODS: An in vitro cartilage permeation model was
developed and utilized to determine the permeability of articular cartilage to
the matrix metalloprotease inhibitors of different hydrophilicity. Permeability
coefficients were obtained by measuring the steady-state flux of the inhibitor
compounds. HPLC methods were also developed and employed for the analysis of drug
levels in assay media. RESULTS: The relationship between permeability and
hydrophilicity of drug molecules was examined. Results indicated that the
permeability coefficient increased with increasing hydrophilicity of the
molecule. Additionally, the relationship between the permeability and the
location of the cartilage section within the animal joint was investigated. Our
results showed that the drug molecules penetrated faster in the surface layer
cartilage than in the deep layer cartilage. CONCLUSIONS: Increasing the
hydrophilicity of a molecule would increase its permeability across articular
cartilage. The in vitro cartilage permeation model developed could be used to
rank order drug compounds according to their cartilage permeability profiles and
to aid in drug selection and development.
PMID- 9755893
TI - Mechanisms of liposomes/water partitioning of (p-methylbenzyl)alkylamines.
AB - PURPOSE: The objective of this study was to compare and interpret the variations
in lipophilicity of homologous (p-methylbenzyl)alkylamines (MBAAs) in isotropic
(octanol/water) and anisotropic (zwitterionic liposomes/water) system. METHODS:
Two experimental approaches were used, namely the pH-metric method to measure
lipophilicity parameters in octanol/water and liposomes/water systems, and
changes in NMR relaxation rates to validate the former method and to gain
additional insights into the mechanisms of liposomes/water partitioning. RESULTS:
For long-chain homologues (N-butyl to N-heptyl), the octanol/water and
liposomes/water systems mostly expressed hydrophobicity. In contrast, the
lipophilicity of the shorter homologues (N-methyl to N-propyl) in the two systems
expressed various electrostatic and polar interactions. CONCLUSIONS: The study
sheds light on the molecular interactions between zwitterionic liposomes and
amphiphilic solutes in neutral and cationic form.
PMID- 9755895
TI - Prodrugs of gestodene for matrix-type transdermal drug delivery systems.
AB - PURPOSE: The aim of this study was to enhance the transdermal absorption of the
highly active progestin gestodene from matrix type transdermal delivery systems
(TDDS) by formation of prodrugs with improved matrix solubility. METHODS:
Gestodene esters were synthesized via acylation of the drug with the respective
carboxylic anhydrides. Subsequently TDDS were produced using the solvent cast
method. Selected formulations were examined with in vitro diffusion experiments
using skin of nude mice. RESULTS: One prodrug, gestodene caproate proved to be an
oil at ambient temperature and showed a very high solubilty of over 10.5% in the
TDDS matrix. Within in vitro penetration studies using those systems the prodrug
exhibited a significantly higher transdermal penetration rate than gestodene from
reference systems. Furthermore, the prodrug was hydrolyzed to the parent drug to
a high extent during the passage of the skin. CONCLUSIONS: Designing prodrugs to
the requirements of matrix TDDS is an efficient way of enhancing the transdermal
drug flux rate.
PMID- 9755896
TI - Characterization of three crystalline forms (VIII, XI, and XII) and the amorphous
form (V) of delavirdine mesylate using 13C CP/MAS NMR.
AB - PURPOSE: The application of solid-state nuclear magnetic resonance (NMR)
characterization of three crystalline forms (VIII, XI, XII) and the amorphous
form V of delavirdine mesylate (DLV-M) is presented. METHODS: Conventional 13CCP
(cross-polarization)/MAS (magic angle spinning) NMR and related spectral editing
methods were employed. NMR relaxation times (T1pH, T1H, and T1C) were also
measured. RESULTS: Distinctly different spectral features among the four solid
forms were observed, indicating high sensitivity of 13C NMR to the variations in
solid structure. Assessment based on NMR data suggests that both anhydrous forms
VIII and XI may contain one molecule per asymmetric unit. DLV may adopt a similar
molecular conformation in the two forms. In contrast, form XII is found to
consist of two molecules per asymmetric unit. Molecule conformation of DLV in
forms VIII, XI, and XII is altered from the dominant conformer in solution. The
amorphous form V may contain DLV molecules of a variety of conformations. NMR
relaxation times (T1PH, T1H, and T1C) provide valuable information about the
motional characteristics in these solids. Values and the rank order of T1pH, T1H,
and T1C also reveal significant differences in local environments and the short
range order among the four forms. CONCLUSIONS: Four solid forms of DLV-M (V,
VIII, XI, and XII) can be distinctly differentiated by 13C CP/MAS NMR
spectroscopy and their structural difference can be partially revealed without
obtaining single crystal data. NMR relaxation times reveal motion dynamics and
aid structural elucidation for these forms.
PMID- 9755897
TI - Self-association properties of monomeric insulin analogs under formulation
conditions.
AB - PURPOSE: The purpose of the current study was to investigate the effects of two
important excipients, zinc and m-cresol, on the self-association properties of a
series of monomeric insulin analogs. In this way, the effects on formulation
behavior of individual amino acid substitutions in the C-terminal region of the
insulin B-chain could be compared. METHODS: The self-association of ten insulin
analogs was monitored by equilibrium and velocity analytical ultracentrifugation
under three different conditions: (i) in neutral buffer alone; (ii) in neutral
buffer containing zinc ion; and (iii) in neutral buffer containing both zinc ion
and phenolic preservative (a typical condition for insulin formulations). The
self-association properties of these analogs were compared to those of human
insulin and the rapid-acting insulin analog Lys(B28)Pro(B29)-human insulin.
RESULTS: The analogs in the current study exhibited a wide range of association
properties when examined in neutral buffer alone or in neutral buffer containing
zinc ion. However, all of these analogs had association properties similar to
human insulin in the presence of both zinc and m-cresol. Under these formulation
conditions each analog had an apparent sedimentation coefficient of s* = 2.9-3.1
S, which corresponds to the insulin hexamer. CONCLUSIONS: Analogs with changes in
the B27-B29 region of human insulin form soluble hexamers in the presence of both
zinc and m-cresol, and m-cresol binding overrides the otherwise destabilizing
effects of these mutations on self assembly.
PMID- 9755898
TI - Effect of gelation on the chemical stability and conformation of leuprolide.
AB - PURPOSE: The purpose of this study was to characterize the conformation,
aggregation, and stability of leuprolide on gelation. METHODS: Infrared spectra
(FTIR) of leuprolide solutions and gels were collected in water, propylene glycol
(PG), dimethyl sulfoxide (DMSO), and trifluoroethanol (TFE). Leuprolide solution
and gel stability data were obtained by SEC and RP-HPLC. RESULTS: Leuprolide was
induced to gel with increasing peptide concentration, introduction of salts, and
gentle agitation. Leuprolide dissolved in water (400 mg/ml) demonstrated FTIR
spectra consisting of two major bands of equal intensity at 1615 cm(-1) and 1630
cm(-1), similar to inter- and intra-molecular beta-sheet structure in proteins.
When samples were gently agitated for 24 hours at 25 degrees C, the formulation
was observed to change from a viscous liquid to an opaque gel with a concomitant
shift in infrared spectra from the equal intensity bands to mostly 1630 cm(-1),
indicating a shift to a preferred beta-sheet structure. Incubation of leuprolide
with 20-200 mM salts at 25 degrees C and 37 degrees C also produced gels ranging
from clear to cloudy and stringy white precipitates. The gel and precipitate were
marked by a shift of the predominant beta-sheet band to 1630 cm(-1) and 1615 cm(
1), respectively. Leuprolide was also observed to gel and/or precipitate in
mixtures of water, PG or TFE, but not in DMSO. CONCLUSIONS: Birefringence was
noted in many of the firmer gels. Both solutions and gels demonstrated minimal
dimer or trimer formation, with no larger order aggregates detected. The chemical
stability profile of gelled leuprolide was similar to that of the non-gelled
water formulation by RP-HPLC.
PMID- 9755899
TI - Degradation kinetics of three gonadorelin analogues: developing a method for
calculating epimerization parameters.
AB - PURPOSE: To develop a method for calculating epimerisation parameters, find out
if the kinetics of the independent reactions can be established, and elucidate
primary structure-chemical degradation relationships in the degradation kinetics
of three gonadorelin analogues. METHODS: The influences of pH, temperature, and
buffer concentration on the degradation of the three gonadorelin analogues
buserelin, goserelin, and triptorelin were investigated using RP-HPLC. A method
was developed to calculate epimerisation and hydrolysis rate constants
independently. RESULTS: Explicit structure-degradation mechanism relations were
found in the degradation of all three compounds. The L-serine residue was found
to be involved in both a solvent-catalysed backbone hydrolysis and a hydroxyl
catalysed epimerisation whereas, the O-tertiary butyl D-serine residue was only
involved in proton-catalysed ether hydrolysis. The kinetics of identical
reactions in different analogues were generally comparable. CONCLUSIONS: The
degradation of the gonadorelin analogues is located at a relatively small number
of chemical residues and prediction of the degradation mechanisms and kinetics of
other peptides with similar structural elements appears to be possible.
PMID- 9755900
TI - Chemical degradation kinetics of recombinant hirudin (HV1) in aqueous solution:
effect of pH.
AB - PURPOSE: To gain information on the chemical stability pattern and the kinetics
of the degradation of recombinant hirudin variant HV1 (rHir), a thrombin-specific
inhibitor protein of 65 amino acids, in aqueous solution as a function of pH.
METHODS: Stability of rHir was monitored at 50 degrees C in the framework of a
classical pH-stability study in aqueous buffers pH 1-9.5. Two capillary
electrophoresis (CE) protocols were used: one for the kinetics of succinimide
formation at Asp53-Gly54 (C-terminal tail) and Asp33-Gly34 (loop section), the
other for the kinetics of rHir degradation. To check for potential effects of
conformational changes by thermal denaturation, circular dichroism (CD)
measurements were performed between 25 and 80 degrees C. RESULTS: Throughout the
pH range studied no effect of thermal denaturation on rHir confirmation at 50
degrees C was observed. rHir was most stable at a neutral pH whereas, at slightly
acidic pH, an intermediate stability plateau was found. Both, strongly acidic and
alkaline conditions led to fast rHir degradation. Depending on the pH of
degradation, rHir was found to degrade in various combinations of multiple
parallel and sequential degradation patterns. Special focus was on succinimide
formation at Asp53-Gly54 (C-terminal tail) and Asp33-Gly34 (loop) and on the
potential of isoAsp formation in position 53 and 33. CONCLUSIONS: Chemical rHir
stability in the intermediate pH range depends strongly on succinimide formation.
At slightly acidic conditions succinimides represent the major degradation
product (up to 40%). Around neutral pH succinimides react further, presumably by
isoAsp formation, and concentrations remain low. Relative preference of
succinimide formation in the C-terminal tail domain versus the loop domain is
explained by higher backbone flexibility in the tail.
PMID- 9755901
TI - Automated covariate model building within NONMEM.
AB - PURPOSE: One important task in population pharmacokinetic/pharmacodynamic model
building is to identify the relationships between the parameters and demographic
factors (covariates). The purpose of this study is to present an automated
procedure that accomplishes this. The benefits of the proposed procedure over
other commonly used methods are (i) the covariate model is built for all
parameters simultaneously, (ii) the covariate model is built within the
population modeling program (NONMEM) giving familiar meaning to the significance
levels used, (iii) it can appropriately handle covariates that varies over time
and (iv) it is not dependent on the quality of the posterior Bayes estimates of
the individual parameter values. For situations in which the computer run-times
are a limiting factor, a linearization of the non-linear mixed effects model is
proposed and evaluated. METHODS: The covariate model is built in a stepwise
fashion in which both linear and non-linear relationships between the parameters
and covariates are considered. The linearization is basically a linear mixed
effects model in which the population predictions and their derivatives with
respect to the parameters are fixed from a model without covariates. The stepwise
procedure as well as the linearization was evaluated using simulations in which
the covariates were taken from a real data set. RESULTS: The covariate models
identified agreed well with what could be expected based on the covariates that
were actually supported in each of the simulated data sets. The predictive
performance of the linearized model was close to that of the non-linearized
model. CONCLUSIONS: The proposed procedure identifies covariate models that are
close to the model supported by the data set as well as being useful in the
prediction of new data. The linearized model performs nearly as well as the non
linearized model.
PMID- 9755902
TI - Correction for non-ideal tracer pharmacokinetic disposition by disposition
decomposition analysis (DDA).
AB - PURPOSE: Pharmacokinetic (PK) studies assume that the tracer's PK is equivalent
to the parent compound. This assumption is often violated. The aim of this work
is to present a method enabling the ideal tracer PK, i.e. the PK of the parent
compound, to be predicted from the non-ideal tracer. METHODS: The procedure uses
a disposition decomposition-recomposition (DDR) that assumes that the labeling
mainly changes the elimination kinetics while the distribution kinetics is not
significantly affected. In the DDR procedure an elimination rate constant
correction factor (kCOR) is determined from a simultaneously fitting to plasma
concentration data resulting from an i.v. injection of both the tracer and the
parent compound. The correction factor is subsequently used to predict the ideal
tracer PK behavior from the disposition function (i.v. bolus response) of the non
ideal tracer. RESULTS: The DDR method when applied to plasma level data of
erythropoietin (r-HuEPO) and its iodinated tracer (125I-r-HuEPO) from a high
(4000U/kg) and a low (400U/kg) dosing of r-HuEPO in newborn lambs (n=13) resulted
in excellent agreements in the elimination rate corrected dispositions in all
cases (r=0.995, SD=0.0095). The correction factor did not show a dose dependence
(p > 0.05). The correction factors were all larger than 1 (kCOR=1.94, SD=0.519)
consistent with a reduction in the EPO elimination by the iodination labeling.
CONCLUSIONS: The DDR tracer correction methodology produces a better
differentiation of the PK of endogenously produced compounds by correcting for
the non-ideal PK behavior of chemically produced tracers.
PMID- 9755903
TI - Correlation of plasma clearance of 54 extensively metabolized drugs between
humans and rats: mean allometric coefficient of 0.66.
AB - PURPOSE: To evaluate the distribution of allometric exponents for relationship of
total plasma clearance of 54 extensively metabolized drugs, with wide-ranging
linear clearance values, between humans and rats, to provide a rationale for the
observed data, and to discuss potential significance of the findings. METHODS:
Human and rat plasma clearance values of 54 drugs with markedly different
physicochemical properties were obtained from the literature. Standard allometric
analysis was performed for each drug using both rat and human data. Unbound vs.
total plasma clearances were obtained for 15 out of 54 drugs and their
correlations between humans and rats were compared. RESULTS: The mean+/-SD of the
allometric exponent for the 54 drugs studied is 0.660+/-0.190. The median
clearance ratio based on unit body weight is 7.41 and the median exponent is
0.645. Excluding two outliers the correlation coefficient of plasma clearance
between humans and rats was 0.745 (p < 0.0001). For the 15 drugs, use of unbound
plasma clearance approach seems to significantly improve the correlation
coefficient compared to total plasma clearance (0.940 vs. 0.841). CONCLUSIONS:
The present study indicates that on average, humans and rats may eliminate
extensively metabolized drugs at a rate similar to that expected from the
allometric or body surface area relationship of basal metabolic rate between the
two species. A simple statistical distribution hypothesis is used to rationalize
the species difference in plasma drug clearance. Rat may serve as an useful
animal model to predict (unbound) plasma clearance of drugs in humans.
PMID- 9755904
TI - Enzymatic degradation of luteinizing hormone releasing hormone (LHRH)/[D-Ala6]
LHRH in lung pneumocytes.
AB - PURPOSE: To investigate the cellular proteolytic activities of various lung
pneumocytes using luteinizing hormone releasing hormone (LHRH) and [D-Ala6]-LHRH
as model peptide substrates. METHODS: HPLC analysis was used to investigate the
degradation kinetics of LHRH/[D-Ala6]-LHRH and to identify their degradation
products in isolated lung pneumocytes. RESULTS: Pulmonary macrophages exhibited
the strongest proteolytic activity against LHRH)/[D-Ala6]-LHRH, followed by type
II and type I-like pneumocytes. Three major degradation products of LHRH, namely
LHRH 4-10, LHRH 6-10, and LHRH 7-10, were identified in macrophages and type II
pneumocytes, whereas in type I-like pneumocytes only the LHRH 7-10 was found. Co
incubation of the cells with known enzyme inhibitors including captopril (an ACE
inhibitor), thiorphan (an EP24.11 inhibitor), and EDTA (an EP24.15 inhibitor)
inhibited the formation of LHRH 4-10, LHRH 7-10, and LHRH 6-10 respectively. In
all cell types, the degradation rate of [D-Ala6]-LHRH was about 3-8 times lower
than that of LHRH. This peptide analog was resistant to degradation by EP24.15
and EP24.11, but was susceptible to ACE. CONCLUSIONS: ACE, EP24.11, and EP24.15
are the major enzymes responsible for the degradation of LHRH in macrophages and
type II pneumocytes. The magnitude of peptidase activities in these cell types
are: EP24.15 > EP24.11 approximately ACE. No EP24.15 or ACE activity was observed
in type I-like pneumocytes and only a weak EP24.11 activity was detected.
PMID- 9755905
TI - The roles of depot injection sites and proximal lymph nodes in the presystemic
absorption of fluphenazine decanoate and fluphenazine: ex vivo experiments in
rats.
AB - PURPOSE: The release and presystemic absorption of fluphenazine and its decanoate
ester from intramuscular depots were investigated. METHODS: Rats were sacrificed
in groups of three at various times after injection of drug or prodrug in sesame
oil. Muscle tissues at the injection sites and various lymph nodes were excised.
Blood (plasma) was harvested by cardiac puncture. RESULTS: Following
administration of fluphenazine decanoate, the amount of prodrug at the sites of
injection declined exponentially (half-life 3.4 days). Highest concentrations of
drug and prodrug were found in iliac and hypogastric lymph nodes nearest to
injection sites in which both analytes were detectable 28 days post dose. The
half-life for the decline of fluphenazine from lymph nodes (4.6 days) was similar
to that from plasma (4.3 days). Following administration of fluphenazine base,
only 2.8% of the dose remained at the sites of injection after 2 days.
Concentrations of drug in iliac and hypogastric lymph nodes were comparable to
those in distal lymph nodes. Fluphenazine concentrations in the lymphatic tissues
decreased at about the same rate as plasma concentrations. CONCLUSIONS: The rate
limiting step appeared to be slow partitioning of the decanoate from oily
deposits at the injection site and proximal lymph nodes with subsequent
hydrolysis of the ester group.
PMID- 9755906
TI - Correlating partitioning and caco-2 cell permeability of structurally diverse
small molecular weight compounds.
PMID- 9755907
TI - Cellular uptake study of biodegradable nanoparticles in vascular smooth muscle
cells.
PMID- 9755909
TI - Endoscopic parathyroidectomy by a gasless approach.
AB - Endoscopic approach for the treatment of primary hyperparathyroidism is one of
the new fields of interest for minimally invasive surgery. The removal of the
parathyroid gland can be achieved either by a gas or gasless technique. Massive
carbon dioxide (CO2) diffusion and absorption has been reported to occur during
the gas procedure. Endoscopic techniques that do not rely on CO2 insufflation
have still to be set. We have developed a new procedure that was offered to 20
selected patients with a localized parathyroid adenoma. A 3-minute CO2
insufflation (12 mm Hg) through a conventional trocar inserted under the strap
muscles is used just to anatomically dissect the virtual thyrotracheal groove.
Actually, the working space is maintained by means of skin retractors so as to
allow needlescopic instruments to perform a parathyroid adenomectomy with the
gasless procedure. In all cases the parathyroid adenoma was removed through a 1.5
cm skin incision. Quick parathyroid hormone assays always confirmed the removal
of all pathologic glands and permitted unilateral cervical exploration. Mean
operative time was 71.7 +/- 35.5 minutes. No complication was registered. At
follow-up, all patients were normocalcemic. This new endoscopic approach to the
neck seems to be safe, effective, and cosmetically satisfactory.
PMID- 9755908
TI - Effect of neutral endopeptidase inhibition on the natriuresis and renal clearance
of atrial natriuretic peptide in perfused rat kidney.
PMID- 9755910
TI - Midterm results of thoracoscopic surgery for pulmonary metastases especially from
colorectal cancers.
AB - Indications for thoracoscopic metastatectomy remain controversial because not all
metastatic tumors may be detected without the manual palpation that is possible
with thoracotomy. However, the accuracy (92%) of preoperative lung imaging in
patients with one or two lesions led us to re-evaluate thoracoscopic
metastatectomy with patient survival as the primary end point. Thoracoscopic
wedge resection using an endoscopic stapling device or video-assisted thoracic
surgery (VATS) lobectomy was performed in patients with one or two pulmonary
metastases. Thoracoscopic resection was performed in 27 patients with 22 solitary
lesions and 5 patients with two lesions. The primary tumors were colorectal
cancer (15), testicular cancer (3), osteosarcoma (2), and seven other
histologies. In 5 of 27 patients (18.5%) a thoracoscopic operation was converted
to a VATS procedure, which requires minithoracotomy to identify metastasis
primary by digital palpation. The 3-year survival rate for colorectal cancer
patients who underwent thoracoscopic resection was 56.4%, in comparison to 48.6%
in historical control thoracotomy patients (n = 16). There was no statistically
significant difference between the two groups. Thoracoscopic resection of one or
two colorectal cancer lung metastases results in a survival rate similar to
standard thoracotomy, and thereby provides an acceptable alternative to this more
invasive approach.
PMID- 9755911
TI - Laparoscopic resection of esophageal epiphrenic diverticulum.
AB - Symptomatic esophageal epiphrenic diverticula are usually repaired with a
diverticulectomy and esophagomyotomy via a left thoracotomy with substantial
postoperative pain and morbidity. If a laparoscopic approach could be shown to be
safe and effective, the decrease in postoperative pain and potentially shorter
hospital stay would make this technique beneficial. We report three cases
repaired via a transabdominal approach. The first two cases were done
laparoscopically. The third case was attempted laparoscopically and completed via
a midline laparotomy, demonstrating that thoracotomy is not necessary even if
laparoscopy is not possible. All three patients had long-standing debilitating
symptoms refractory to standard nonsurgical therapies (botulinum toxin injection,
pneumatic dilation, antispasmodic medication) with abnormal esophageal motility.
There was one intraoperative complication of a left pneumothorax that required
neither laparotomy nor thoracostomy. An esophagram on the first postoperative day
demonstrated no extravasation and good flow into the stomach. The postoperative
course was uneventful for all three patients, with the laparoscopic patients
discharged on the second postoperative day and the laparotomy patient discharged
on the seventh postoperative day. In conclusion, laparoscopic repair of
symptomatic esophageal epiphrenic diverticula is a safe and effective technique
with minimal postoperative pain and morbidity. It should be considered as an
alternative to the traditional transthoracic approach, and may become the
standard technique.
PMID- 9755913
TI - Laparoscopic cholecystectomy facilitated by hydrodissection.
AB - Hydrodissection has been used in the past in open cholecystectomy to facilitate
dissection in difficult cases. Injection of 50 mL of saline, with a laparoscopic
cyst aspiration needle during laparoscopic cholecystectomy between the
gallbladder and the liver, causes an edematous area 1-1.5 cm thick between the
gallbladder and the liver. This allows dissection to be carried out prograde and
retrograde with less bleeding and a much smaller chance of gallbladder
perforation and the escape of stones. One hundred and thirty-three laparoscopic
cholecystectomies (LC) utilizing hydrodissection were compared to 48 historical
controls (HC), comparing blood loss, stone spillage, and dissection time. Blood
loss was on average less than 5 mL in the LC group and 56 mL in the HC. One case
of minor biliary spillage occurred in the LC group and 11 gallbladder
perforations in the HC group. Time taken for the dissection was 6.4 minutes for
LC and 16 minutes for HC. Laparoscopic hydrodissection was accompanied by less
bleeding, fewer incidents of gallbladder damage and stone spilling, and a much
faster dissection time. It can also be performed prograde, which is helpful in
liver cirrhosis.
PMID- 9755914
TI - The multimedia CD ROM: an innovative teaching tool for endoscopic sinus surgery.
AB - The recent explosive growth in the use of endoscopic techniques in the
performance of surgical procedures has created an important need for educational
materials on this subject. However, limitations of currently available teaching
tools frustrate the user and hamper the teaching and spread of these procedures.
To improve on currently available methods, we developed a CD ROM video atlas of
techniques in endoscopic sinus surgery (ESS). The multimedia CD ROM video atlas
combines the best features of the surgical atlas with conventional videotapes.
The component steps of procedures in ESS are presented to the viewer as brief,
individual video sequences, accompanied by narration and a text of the highlights
of each procedure. The use of digital video allows the user to access the segment
of interest directly, in the order of preference, without having to sift through
the other segments, as with conventional videocassettes. An interface allows
control over playback of the video, and sequences can be reviewed instantly.
Storage capacity of the CD ROM allows up to 60 minutes of video to be stored on
each disk. The CD ROM combines the best elements of currently available
educational tools and may represent a new approach for medical education.
PMID- 9755912
TI - Interval appendectomy for perforated appendicitis in children.
AB - To determine the efficacy, safety, and cost of managing perforated appendicitis
with intravenous antibiotics followed by an interval appendectomy, the charts of
87 children with ruptured appendicitis were retrospectively reviewed. These
patients were treated with intravenous fluid resuscitation and antibiotics
(consisting of clindamycin and ceftazidime) and underwent appendectomy, either on
that admission (n = 46) or as a delayed interval procedure (n = 41). Antibiotics
in all cases were discontinued either at home or in the hospital after the child
was a febrile for 48 hours with normal white and differential blood cell counts,
and the two groups were compared. Seven patients (17%) "failed" the interval
appendectomy protocol. All but one "failure" was due to the development or
persistence for >72 hours of a bowel obstruction. The data are described below as
percent or mean +/- 1 standard deviation. [table: see text] We conclude that
antibiotics and interval appendectomy is a safe effective alternative for the
management of perforated appendicitis. When successful, hospitalization, charges,
and morbidity are less with this approach. A persistent bowel obstruction for 72
hours is an indication to proceed with appendectomy on admission.
PMID- 9755915
TI - Laparoscopic treatment of traumatic diaphragmatic hernia.
AB - Traumatic diaphragmatic hernia is rare, but is of utmost importance due to its
high morbidity and mortality. It is markedly important in patients with blunt
abdominal trauma, and diagnosis is difficult because of the numerous associated
injuries. A patient with few symptoms of chronic traumatic diaphragmatic hernia
is described, who underwent surgery due to a gastric volvulus. Laparoscopic
surgery permits repair of these injuries through an abdominal approach, avoiding
a thoracic incision or selective intubation.
PMID- 9755916
TI - Gallbladder duplication and laparoscopic management.
AB - Gallbladder duplication can present a significant challenge to the laparoscopic
surgeon, primarily due to difficulties with diagnosis and recognition. Previous
reports of attempted laparoscopic cholecystectomy in patients with gallbladder
duplication resulted in incomplete or staged multiple procedures. The case report
of a 35-year-old woman with successful laparoscopic management of symptomatic
gallbladder duplication is described, emphasizing several important
considerations. Preoperatively when evaluating radiologic studies a high index of
suspicion is necessary in interpreting atypical findings. To further evaluate
these abnormalities, liberal use of preoperative ERCP is helpful, and specific
endoscopic techniques may be necessary as well. Intraoperatively, the findings
may be confusing, and cholangiography can help clarify ductular anomalies,
especially if the gallbladder duplication is contained within a common serosal
coat. Missing a second gallbladder can result in persistent symptoms
postoperatively necessitating further surgery. Laparoscopic cholecystectomy in
the management of gallbladder duplication can be safely done and an awareness is
necessary to avoid complications or multiple procedures.
PMID- 9755917
TI - Laparoscopic complete excision of a splenic epidermoid cyst.
AB - Splenic epidermoid cysts are rare lesions traditionally treated by splenectomy.
Concerns about overwhelming postsplenectomy sepsis have led to the development of
splenic preservation procedures in the treatment of cystic diseases of the
spleen. We present the first case report of successful laparoscopic complete
excision of a splenic epidermoid cyst.
PMID- 9755918
TI - Intragastric migration of laparoscopic adjustable gastric band (Lap-Band) for
morbid obesity.
AB - The appearance of fistulas and the posterior intragastric inclusion of the
adjustable silicone Lap-Band prothesis have been described, representing a severe
complication of the Lap-Band procedure. A 45-year-old patient with severe
obesity, weighing 115 kg, and having BMI (body max index) of 45 kg/m2 was
assigned to a protocol to place a Lab-Band in her. An infection in the reservoir
after 9 months indicated the beginning of the appearance of fistulas. The entire
adjustable silicone gastric band device eroded inside the stomach between months
9 and 14 after its placement, resulting in reoperation. The gastric inclusion of
the Lap-Band device represents a severe complication that requires reoperation,
and raises concerns about the safety of this new alternative weight reduction
operation.
PMID- 9755919
TI - Regarding laparoscopic staging for Hodgkin's disease.
PMID- 9755921
TI - Bibliography.
PMID- 9755920
TI - Regarding laparoscopy-associated mesenteric vascular events: descript of an
evolving clinical syndrome.
PMID- 9755922
TI - Tuberculosis 2000: problems and solutions.
AB - The incidence of tuberculosis is expected to increase, from 8.8 million cases in
1995, to 10.2 million cases by the year 2000 and 11.9 million by 2005. Three
million deaths due to tuberculosis occurred in 1995, and 3.5 million can be
expected in the year 2000. The most important causes of the world-wide increase
in tuberculosis are: 1) non-compliance with control programmes; 2) inadequate
diagnosis and treatment; 3) migration; 4) endemic human immunodeficiency virus
(HIV); 5) ambulatory and self-administered treatment. In the 1970s it was stated
that treatment needed to be supervised-a recommendation that went unheeded. A
number of fundamental changes should be introduced in order to make treatment
effective, to cure patients and thus to arrest the transmission of the disease:
1) supervision during the whole period antituberculosis drugs are taken, and 2)
hospitalization during the initial treatment stage for all groups at risk. It is
already 50 years since the first antituberculosis drugs were discovered;
effective treatments capable of curing all patients in 6 months have been
available for the last 25 years, and the result is failure plus a growing
mortality curve at the beginning of the twenty-first century. If we wish to alter
this trend, we need trained doctors all over the world who possess enough
clinical knowledge of tuberculosis; hospitalization for specific groups of
tuberculosis patients; true supervision during the whole treatment period; fixed
dose combinations of drugs; and prophylaxis or preventive treatment whenever
possible. We also need to take into account other factors such as drug
resistance, endemic HIV, and migration.
PMID- 9755923
TI - Intensive short course chemotherapy in the management of tuberculous meningitis.
AB - SETTING: Short course chemotherapy for tuberculous meningitis (TBM) is advocated
by several groups, but relatively few children have been so treated and followed
up. METHODS: A prospective, observational study of isoniazid (INH), rifampicin
(RMP) and ethionamide (ETH) in a dosage of 20 mg/kg, and pyrazinamide (PZA) 40
mg/kg, all given once daily in hospital for 6 months. Surviving children were
followed up for a year after discharge. RESULTS: Ninety five children, 39 (41%)
at stage III, 52 (55%) at stage II and 4 (4%) at stage I TBM were studied. Ten
(26%) at stage III and 3 (6%) at stage II died before completion of therapy. Five
surviving children (6%) moved on discharge and were untraceable; seven children
(9%) were lost during follow up and three were inadvertently restarted on
antituberculosis therapy. Two children with severe stage III disease died after
discharge. One child experienced a probable disease recrudescence 1 month after
discharge. Eighteen children (20%) developed a mildly elevated serum bilirubin
concentration during the first month of treatment. In five of these children INH,
RMP, ETH and PZA were stopped and streptomycin (SM) and ethambutol substituted.
In all cases the original treatment was restarted without incident. One child
developed overt jaundice after 5 months of treatment due to hepatitis A
infection. CONCLUSIONS: Our experience suggests that young children with TBM can
be safely treated for 6 months with high doses of antituberculosis agents without
overt hepatotoxicity and with a low risk of relapse.
PMID- 9755924
TI - Factors determining the outcome of treatment of adult smear-positive tuberculosis
cases in The Gambia.
AB - SETTING: Health centres in The Gambia, West Africa. OBJECTIVES: To identify
factors determining the outcome of treatment of adult tuberculosis cases in a
Tuberculosis Control Programme using directly observed treatment. DESIGN:
Information on the outcome of treatment was collected on all tuberculosis cases
registered with the Tuberculosis Control Programme in 1994 and 1995 and treated
under supervision by tuberculosis control staff, nurses or village health
workers. Treatment outcome was recorded as cured, completed treatment, failed,
defaulted or died. Transferred-out patients were traced and their treatment
outcome recorded at the health centre where they had last been seen. RESULTS:
Data were analysed for 1357 adult smear-positive tuberculosis cases. Sputum smear
conversion 2 months after the start of treatment was observed in 90% of smear
positive cases and was more likely to occur if the initial bacterial load in the
sputum was low. The total cure rate was 74.6%. Female tuberculosis patients were
more likely to achieve cure than males. Adjusting for sex, the cure rate was
higher when treatment was provided by tuberculosis control staff in the main
health centres rather than by nurses or village health workers at the peripheral
level (odds ratio [OR] = 1.60, 95% confidence interval [CI] 1.23-2.09). The
absence of sputum smear conversion after 2 months of chemotherapy was associated
with defaulting later during treatment (OR = 2.0, 95% CI 1.15-3.57). Adjusting
for age and sex, the death rate during treatment was higher in human
immunodeficiency virus (HIV) positive than in HIV-negative tuberculosis patients.
CONCLUSION: Directly observed treatment is an effective intervention for
improving adherence of tuberculosis patients to treatment in a resource-poor
country, provided that drugs are effectively delivered to the most peripheral
level, and that health staff are adequately trained and regularly supervised.
Patients with high bacterial load in initial sputum smears need to be closely
supervised, as they are more likely to default from treatment.
PMID- 9755925
TI - Plasma zinc status in Indian childhood tuberculosis: impact of antituberculosis
therapy.
AB - SETTING: Department of Paediatrics and Biochemistry, Postgraduate Institute of
Medical Education and Research, Chandigarh, India. OBJECTIVE: To assess the
plasma zinc status in children with tuberculosis and to correlate it with
nutritional status, activity and severity of disease in relation to
antituberculosis therapy. DESIGN: The plasma zinc status of 50 children with
different forms of tuberculosis was compared with 10 healthy and 10 malnourished
children without tuberculosis at 0, 1, 2, 3 and 6 months of antituberculosis
therapy. RESULT: The mean plasma zinc concentration in children with pulmonary
tuberculosis (n = 20) was 68.65+/-2.50 microg/dl, central nervous system (CNS)
tuberculosis (n = 10) was 64.20+/-3.82 microg/dl, tuberculous lymphadenitis (n =
10) was 63.2+/-3.77 microg/dl and disseminated tuberculosis (n = 10) was 59.0+/
2.75 microg/dl at 0 months. The mean plasma zinc level of healthy children was
129.10+/-3.01 microg/dl and in malnourished non-tuberculous children it was
108.40+/-3.16 microg/dl. Thus children with tuberculosis had significantly lower
plasma zinc level than those without tuberculosis, irrespective of their
nutritional status (P < 0.001). There was a significant rise in zinc level at the
end of 6 months of antituberculosis therapy (P < 0.001). CONCLUSION: Plasma zinc
status may prove to be a good objective marker for monitoring the severity of the
disease and the response to therapy.
PMID- 9755926
TI - The cost of tuberculosis to patients in Sierra Leone's war zone.
AB - OBJECTIVE: To evaluate how the extreme poverty of the patients and the poor
salaries of the staff combined to increase the cost of treatment to patients
within the subsidised national tuberculosis programme in Sierra Leone.
DESIGN/SETTING: From September to December of 1994, semi-structured interviews
were conducted with 72 patients and 17 staff of the National Leprosy and
Tuberculosis Control Programme of Sierra Leone, a screening and treatment
programme funded by international donors. RESULTS: Although some extra costs were
indeed incurred within the subsidized national tuberculosis treatment programme,
they were much lower than those incurred during the pre-programme period when the
patients sought intermittent help from a wide range of traditional and biomedical
sources within the plural healing continuum. The national politico-economic
crisis, and the consequent poverty of most patients, impeded compliance with and
sustainability of treatment, even within the formal subsidised treatment
programme. CONCLUSIONS: More money was spent by patients on treatment in the
months/years preceding entry into the national tuberculosis programme. Many
factors retarded entry, including poor communications, misinformation,
malpractice by health professionals, and displacement resulting from chronic
internal warfare. The war intensified all factors that predispose to tuberculosis
and retarded access to treatment. Supra-programme cost, or 'corruption,' was
minimal due to the poverty of health professionals, with a few salient
exceptions.
PMID- 9755927
TI - Drug-resistant tuberculosis in Budapest.
AB - SETTING: Sixteen districts of Budapest, Hungary. OBJECTIVE: To determine the
frequency of primary and secondary drug resistance, and to recommend treatment
regimens. DESIGN: A retrospective survey. METHODS: Mycobacterium tuberculosis
isolates were collected from 264 newly diagnosed and 147 previously treated
patients. All strains were tested against isoniazid (INH), rifampicin (RIF),
streptomycin (SM) and ethambutol (EMB) using the proportion method. Bacteriologic
examinations were performed in the Diagnostic Laboratory of the Koranyi National
Institute for Tuberculosis and Pulmonology in Budapest. RESULTS: Primary
resistance to INH alone was 4%, to SM alone 2%, to RIF alone 0.4%, to INH and SM
1%, and to INH, RIF, SM and EMB 0.4%. Of the isolates of 78 relapse cases, six
(8%) were resistant to INH alone, one (1%) to INH and RIF, two (3%) to INH, RIF,
SM and EMB. Of the isolates of 69 patients notified with active tuberculosis for
over a year, 51 (74%) were susceptible to the drugs tested. CONCLUSION: Based on
the level of primary drug resistance as well as on the resistance pattern of
relapse cases, it is recommended to start the treatment of newly detected and
relapse cases with four drugs. The high rate of chronic cases with susceptible
strains can be explained by poor compliance. To prevent development of resistant
cases and to achieve good compliance, it is necessary to apply direct observation
of treatment in all types of patients.
PMID- 9755928
TI - Metronidazole has no antibacterial effect in Cornell model murine tuberculosis.
AB - SETTING: Experiments in vitro on the bactericidal activity of metronidazole and
in the Cornell model of murine tuberculosis. OBJECTIVE: To assess the sterilising
activity of maximal metronidazole dosage and its activity against bacilli held
dormant by immunity in the mouse. DESIGN: In vitro experiments showed that
metronidazole was only bactericidal at attainable concentrations (50-100
microg/ml) under anaerobic conditions. In the Cornell model, isoniazid 25 mg/kg
and high dosage pyrazinamide 1000 mg/kg was given in the diet with and without
1500 mg/kg metronidazole for the initial 14 weeks of sterilising chemotherapy. In
the subsequent sterile state, metronidazole at 0, 100 and 250 mg/kg was given by
daily gavage for 6 weeks. Finally, the mice were given 3 weeks of high dosage
steroids and their organs were cultured in selective liquid medium. RESULTS:
Metronidazole had no activity either in the initial sterilising phase or in the
subsequent sterile state. CONCLUSION: The O2 tension in the cellular lesions of
murine tuberculosis is unlikely to be sufficiently low to allow metronidazole to
act. Its activity should be assessed in caseous lesions.
PMID- 9755930
TI - E-test for susceptibility testing of Mycobacterium tuberculosis.
AB - SETTING: Initial isolates should be tested for drug susceptibility to confirm the
anticipated effectiveness of chemotherapy. OBJECTIVE: To evaluate E-test strips
for susceptibility testing of Mycobacterium tuberculosis. DESIGN: A proportion
method using Lowenstein-Jensen medium and the Bactec radiometric system were
compared with the E-test (isoniazid [INH], rifampicin [RMP], ethambutol [EMB] and
streptomycin [SM]). RESULTS: For 73 of the 81 M. tuberculosis isolates (90.1%)
the proportion and E-test methods yielded concordant susceptibility results
against all four antimicrobial agents tested. Of these 73 strains, 69 were fully
susceptible; the four isolates showing resistance to antimicrobial drugs by both
methods were also resistant when tested by Bactec 460TB. While the proportion
method indicated susceptibility for the eight remaining strains, E-test results
showed mono EMB resistance in five strains, INH resistance for two isolates
(including one isolate resistant to EMB plus INH), and for one strain E-test
yielded resistance to EMB and SM. Using Bactec as the reference method, the E
test resulted in false resistance in eight strains and no false susceptibility.
CONCLUSION: Due to a substantial rate of false resistance, this method cannot be
recommended at present for practical use in clinical laboratories.
PMID- 9755929
TI - Molecular epidemiology of tuberculosis in Cuba outside of Havana, July 1994-June
1995: utility of spoligotyping versus IS6110 restriction fragment length
polymorphism.
AB - SETTING: Molecular typing has become an important tool for examining the extent
of active transmission of tuberculosis. OBJECTIVES: To examine transmission of
tuberculosis in Cuba using IS6110 restriction fragment length polymorphism (RFLP)
typing and to evaluate the utility of spoligotyping. DESIGN: One hundred and
sixty Mycobacterium tuberculosis strains isolated over a one year period in Cuba
were subjected to RFLP and spoligotyping. RESULTS: Forty-eight percent of the
isolates were found in 19 clusters of strains with identical RFLP patterns. In
general, cluster sizes were limited, except for two large institutional
outbreaks. Age was strongly inversely correlated to clustering. Most streptomycin
resistant isolates were found in clusters. Fifteen spoligotype clusters comprised
78% of the isolates. Significantly different IS6110 RFLP types subdivided 11
spoligotype clusters, whereas none of the IS6110 clusters were subdivided by
spoligotyping. CONCLUSIONS: Considering the short study period, 48% clustering is
high, indicating that recent transmission plays an important role in Cuba.
Although resistance is still a minor problem, transmission of streptomycin
resistant strains occurs. The high polymorphism observed with IS6110 RFLP
indicates that this marker is useful for future molecular epidemiological studies
in Cuba. Spoligotyping appeared less suitable for population-based studies.
PMID- 9755931
TI - Limitations and requirements for quality control of sputum smear microscopy for
acid-fast bacilli.
AB - Sputum microscopy for acid-fast bacilli (AFB) is considered to be the most
appropriate method for case-finding in a tuberculosis (TB) control programme. It
is usually carried out by general technicians, often after minimal training.
Quality control of their results therefore seems indispensable. The methods
advocated for quality control are reviewed. Controls by culture leave too much
uncertainty because of big differences in technical characteristics of the
methods. Sets of smears sent out by a central laboratory can only be used to
assess capability. Rechecking routine smears allows daily performance to be
appraised and may be a strong motivation, but feasibility may be a problem. Based
on our experience, we describe the technical requirements for cross-checking of
routine smears. Counter-checking slides with discordant results is crucial for
accurate assessments. A sample size should strike a balance between statistical
accuracy and the man-power needed. Indicators for evaluation are proposed that
allow discrimination of error gradings, to be used in a phased manner with
priority at first being given to false negatives and false positives that pass
the threshold for clinical decision-making. Estimates of critical values with
suggestions about their interpretation are placed in the context of supervising
TB laboratories.
PMID- 9755932
TI - Pneumonia due to Leptospira spp.: results of an epidemiological and clinical
study.
AB - OBJECTIVE: To evaluate the prevalence of Leptospira spp. infections in a
population of in- and out-patients with community acquired pneumonia (CAP) and
the incidence of leptospiral pneumonia. DESIGN AND RESULTS: Of 176 patients
infected with CAP who were evaluated for the presence of Leptospira spp. as
causative agent, 10 were found positive for leptospiral antibodies (prevalence
rate: 5.7%), but seroconversion was observed in only one case (incidence rate:
0.6%). The patient had had recent contact with possibly contaminated water. She
had pulmonary involvement and signs of mild hepatic damage, but recovered fully.
CONCLUSION: The authors highlight the importance of testing for leptospirosis in
case of pneumonia in endemic areas where the more common causative pathogens for
CAP can not be documented and when initial empiric therapy is ineffective.
PMID- 9755933
TI - Serum vitamin A levels during tuberculosis and human immunodeficiency virus
infection.
AB - Vitamin A deficiency during tuberculosis and human immunodeficiency virus (HIV)
infection has not been characterized. A cross-sectional study was conducted among
HIV-infected adults with tuberculosis in Butare, Rwanda, in which 29% of the
subjects had serum vitamin A levels consistent with deficiency (<1.05
micromol/L). Women had mean serum vitamin A levels of 1.22+/-0.45, compared with
1.47+/-0.68 in men (P < 0.07). A total of 37% of subjects with recent weight loss
had vitamin A levels consistent with deficiency, compared with 14% of subjects
without weight loss (P < 0.02). This study suggests that vitamin A deficiency is
common among adults with tuberculosis and HIV infection in Rwanda.
PMID- 9755934
TI - Multidrug-resistant tuberculous meningitis in a health care worker.
PMID- 9755935
TI - Implantation of tuberculosis into the chest wall as a complication of fine needle
aspiration of pulmonary tuberculoma.
PMID- 9755936
TI - TB and HIV in Bolivia.
PMID- 9755937
TI - Measured molecular coherent scattering form factors of animal tissues, plastics
and human breast tissue.
AB - Photon scattering angular distributions from various animal tissues were measured
at two energies of a monochromatic synchrotron x-ray beam. Two plastics and human
breast tissue were also measured. From these two measurements, the molecular
coherent scattering form factor of each material was extracted. A new data
analysis technique that uses Monte Carlo based corrections for air scattering,
incoherent scattering and multiple scattering was used. The form factors of the
16 materials are presented in tabular form, suitable for use in computer
calculations.
PMID- 9755938
TI - Accuracy of subsurface temperature distributions computed from pulsed
photothermal radiometry.
AB - Pulsed photothermal radiometry (PPTR) is a non-contact method for determining the
temperature increase in subsurface chromophore layers immediately following
pulsed laser irradiation. In this paper the inherent limitations of PPTR are
identified. A time record of infrared emission from a test material due to laser
heating of a subsurface chromophore layer is calculated and used as input data
for a non-negatively constrained conjugate gradient algorithm. Position and
magnitude of temperature increase in a model chromophore layer immediately
following pulsed laser irradiation are computed. Differences between simulated
and computed temperature increase are reported as a function of thickness, depth
and signal-to-noise ratio (SNR). The average depth of the chromophore layer and
integral of temperature increase in the test material are accurately predicted by
the algorithm. When the thickness/depth ratio is less than 25%, the computed peak
temperature increase is always significantly less than the true value. Moreover,
the computed thickness of the chromophore layer is much larger than the true
value. The accuracy of the computed subsurface temperature distribution is
investigated with the singular value decomposition of the kernel matrix. The
relatively small number of right singular vectors that may be used (8% of the
rank of the kernel matrix) to represent the simulated temperature increase in the
test material limits the accuracy of PPTR. We show that relative error between
simulated and computed temperature increase is essentially constant for a
particular thickness/depth ratio.
PMID- 9755939
TI - Near-infrared optical properties of ex vivo human skin and subcutaneous tissues
measured using the Monte Carlo inversion technique.
AB - The absorption and transport scattering coefficients of caucasian and negroid
dermis, subdermal fat and muscle have been measured for all wavelengths between
620 and 1000 nm. Samples of tissue 2 mm thick were measured ex vivo to determine
their reflectance and transmittance. A Monte Carlo model of the measurement
system and light transport in tissue was then used to recover the optical
coefficients. The sample reflectance and transmittance were measured using a
single integrating sphere 'comparison' method. This has the advantage over
conventional double-sphere techniques in that no corrections are required for
sphere properties, and so measurements sufficiently accurate to recover the
absorption coefficient reliably could be made. The optical properties of
caucasian dermis were found to be approximately twice those of the underlying fat
layer. At 633 nm, the mean optical properties over 12 samples were 0.033 mm(-1)
and 0.013 mm(-1) for absorption coefficient and 2.73 mm(-1) and 1.26 mm(-1) for
transport scattering coefficient for caucasian dermis and the underlying fat
layer respectively. The transport scattering coefficient for all biological
samples showed a monotonic decrease with increasing wavelength. The method was
calibrated using solid tissue phantoms and by comparison with a temporally
resolved technique.
PMID- 9755940
TI - Effect of temperature on the optical properties of ex vivo human dermis and
subdermis.
AB - The effect of temperature on the optical properties of human dermis and subdermis
as a function of near-infrared wavelength has been studied between 25 degrees C
and 40 degrees C. Measurements were performed ex vivo on a total of nine skin
samples taken from the abdomen of three individuals. The results show a
reproducible effect of temperature on the transport scattering coefficient of
dermis and subdermis. The relative change of the transport scattering coefficient
showed an increase for dermis ((4.7+/-0.5) x 10(-3) degrees C(-1)) and a decrease
for subdermis ((-1.4+/-0.28) x 10(-3) degrees C(-1)). Note that the magnitude of
the temperature coefficient of scattering was greater for dermis than subdermis.
A reproducible effect of temperature on the absorption coefficient could not be
found within experimental errors. System reproducibility in transport scattering
coefficient with repeated removal and repositioning of the same tissue sample at
the same temperature was excellent at +/-0.35% for all measurements. This
reproducibility enabled such small changes in scattering coefficient to be
detected.
PMID- 9755941
TI - Calculation of microplanar beam dose profiles in a tissue/lung/tissue phantom.
AB - Recent advances in synchrotron generated x-ray beams with a high fluence rate
permit investigation of the application of an array of closely spaced, parallel
or converging microplanar beams in radiotherapy. The proposed technique takes
advantage of the hypothesized repair mechanism of capillary cells between
alternate microbeam zones, which regenerates the lethally irradiated endothelial
cells. The lateral and depth doses of 100 keV microplanar beams are investigated
for different beam dimensions and spacings in a tissue, lung and
tissue/lung/tissue phantom. The EGS4 Monte Carlo code is used to calculate dose
profiles at different depths and bundles of beams (up to 20 x 20 cm square cross
section). The maximum dose on the beam axis (peak) and the minimum interbeam dose
(valley) are compared at different depths, bundles, heights, widths and beam
spacings.
PMID- 9755942
TI - The calibration of therapy level electron beam ionization chambers in terms of
absorbed dose to water.
AB - During 1998, NPL plans to introduce the world's first absorbed dose calibration
service for electron beam radiotherapy. The service will be based on the primary
standard graphite calorimeter, and will enable the direct calibration of electron
ionization chambers, without reference to air kerma standards. This calibration
is a two-step process. Firstly, a set of NACP-designed parallel-plate reference
chambers have been calibrated against the calorimeter over the last few years.
These chambers are then used to calibrate user chambers by direct comparison in a
water phantom under standard conditions. This paper describes the calibration of
the reference chambers against the calorimeter and the derivation of absorbed
dose to water calibration factors (with an estimated uncertainty in this
calibration of +/-1.50% at the 95% confidence level).
PMID- 9755943
TI - Generation of discrete beam-intensity modulation by dynamic multileaf collimation
under minimum leaf separation constraints.
AB - An algorithm to generate discrete beam-intensity modulation by dynamic multileaf
collimation is presented which incorporates constraints on minimum allowed leaf
separations. MLC positioning information is derived simultaneously for all leaf
pairs and back-up diaphragms as they progress across the field. A feedback
mechanism allows corrections to be applied to eliminate potential violations of
minimum separation conditions and any underexposure in the interleaf tongue-and
groove region as they are encountered. The resulting motion correctly delivers
the intended modulation and is physically realizable. Implementation of the
algorithm is described. Results of the algorithm can also alternatively be
interpreted as defining a series of static fields to deliver the same modulation.
PMID- 9755944
TI - Use of the Cimmino algorithm and continuous approximation for the dose deposition
kernel in the inverse problem of radiation treatment planning.
AB - An approximate continuous data fitting model for the dose deposition kernel was
developed. The model uses a discrete Fourier transform to interpolate dose values
in patient space and intensity distribution in treatment space. The continuous
kernel was applied to the inverse problem of radiation treatment planning. In the
problem a prescribed dose distribution was to be created using intensity
modulation of several fields. The Cimmino algorithm suitable for solving large
systems of inequalities was adapted. Upper and lower dose constraints for
planning target volume (PTV) and organs at risk (OAR) can be implemented into the
algorithm. Using continuous and discrete kernels an intensity modulation was
computed in a two-dimensional phantom with a PTV and low-dose region, and in the
real three-dimensional patient planning. Intensity modulations obtained using
continuous and discrete kernels were in good agreement.
PMID- 9755945
TI - Phase mammography--a new technique for breast investigation.
AB - A new phase radiography technique for investigation and diagnosis of neoplasms in
breast tissue is proposed. Forty-four mammography samples with adenocarcinoma
that had been prepared after mastectomy were tested in a new phase radiography
device. It was shown that the phase images manifest the changes in parenchyma
structure due to malignancy and microcalcifications up to 50 microm in size.
Results obtained were verified by histological examination. A contrast of the
phase images of small microcalcifications and distortions of the stroma
architecture ranges up to 40-60%; spatial resolution is about 20 microm. The
proposed technique offers outstanding possibilities for digital mammography. The
small and large details of structure manifest themselves with practically the
same contrast. Phase images differ from those obtained in mammography and many
details still require further decoding.
PMID- 9755946
TI - Mammography spectrum measurement using an x-ray diffraction device.
AB - The use of a diffraction spectrometer developed by Deslattes for the
determination of mammographic kV is extended to the measurement of accurate,
relative x-ray spectra. Raw x-ray spectra (photon fluence versus energy) are
determined by passing an x-ray beam through a bent quartz diffraction crystal,
and the diffracted x-rays are detected by an x-ray intensifying screen coupled to
a charge coupled device. Two nonlinear correction procedures, one operating on
the energy axis and the other operating on the fluence axis, are described and
performed on measured x-ray spectra. The corrected x-ray spectra are compared
against tabulated x-ray spectra measured under nearly identical conditions.
Results indicate that the current device is capable of producing accurate
relative x-ray spectral measurements in the energy region from 12 keV to 40 keV,
which represents most of the screen-film mammography energy range. Twelve keV is
the low-energy cut-off, due to the design geometry of the device. The
spectrometer was also used to determine the energy-dependent x-ray mass
attenuation coefficients for aluminium, with excellent results in the 12-30 keV
range. Additional utility of the device for accurately determining the
attenuation characteristics of various normal and abnormal breast tissues and
phantom substitutes is anticipated.
PMID- 9755947
TI - Monte Carlo modelling of an extended DXA technique.
AB - The precision achieved in measuring bone mineral density (BMD) by commercial dual
energy x-ray absorptiometry (DXA) machines is typically better than 1%, but
accuracy is considerably worse. Errors, due to inhomogeneous distributions of
fat, of up to 10% have been reported. These errors arise because the DXA
technique assumes a two-component model for the human body, i.e. bone mineral and
soft tissue. This paper describes an extended DXA technique that uses a three
component model of human tissue and significantly reduces errors due to
inhomogeneous fat distribution. In addition to two x-ray transmission
measurements, a measurement of the path length of the x-ray beam within the
patient is required. This provides a third equation, i.e. T = ts + tb + tf where
T, ts, tb and tf are the total, lean soft tissue, bone mineral and fatty tissue
thicknesses respectively. Monte Carlo modelling was undertaken to make a
comparison of the standard and extended DXA techniques in the presence of
inhomogeneous fat distribution. Two geometries of varying complexity were
simulated. In each case the extended DXA technique produced BMD measurements that
were independent of soft tissue composition whereas the standard technique
produced BMD measurements that were strongly dependent on soft tissue
composition. For example, in one case, the gradients of the plots of BMD versus
fractional fat content were for standard DXA (-0.183+/-0.037) g cm(-2) and for
extended DXA (0.027+/-0.044) g cm(-2). In all cases the extended DXA method
produced more accurate but less precise results than the standard DXA technique.
PMID- 9755948
TI - MRI thermometry in phantoms by use of the proton resonance frequency shift
method: application to interstitial laser thermotherapy.
AB - In this work the temperature dependence of the proton resonance frequency was
assessed in agarose gel with a high melting temperature (95 degrees C) and in
porcine liver in vitro at temperatures relevant to thermotherapy (25-80 degrees
C). Furthermore, an optically tissue-like agarose gel phantom was developed and
evaluated for use in MRI. The phantom was used to visualize temperature
distributions from a diffusing laser fibre by means of the proton resonance
frequency shift method. An approximately linear relationship (0.0085 ppm degrees
C(-1)) between proton resonance frequency shift and temperature change was found
for agarose gel, whereas deviations from a linear relationship were observed for
porcine liver. The optically tissue-like agarose gel allowed reliable MRI
temperature monitoring, and the MR relaxation times (T1 and T2) and the optical
properties were found to be independently alterable. Temperature distributions
around a diffusing laser fibre, during irradiation and subsequent cooling, were
assessed with high spatial resolution (voxel size = 4.3 mm3) and with random
uncertainties ranging from 0.3 degrees C to 1.4 degrees C (1 SD) with a 40 s scan
time.
PMID- 9755949
TI - A phantom study evaluating the quantitative aspect of 3D PET imaging of the
brain.
AB - Phantom studies are used to develop a reliable quantitative data processing
protocol for 3D PET brain scanning for conditions typically encountered in FDG
and neuroreceptor brain imaging. These protocols often span several half-lives of
the injected radiotracer thus resulting in a greatly varying statistical content
of the acquired data over the study duration. Detector normalization, scatter
correction and their interplay over a wide range of statistical content of
acquired data were evaluated. Overall sensitivity calibration factors were
determined after all other quantification corrections were applied to the data.
The result is an optimum data processing protocol that includes an iterative
convolution subtraction scatter correction method, a normalization procedure that
takes into account the geometric properties of the scanner and a region of
interest based calibration procedure, applied in this order. This protocol yields
a 3D PET quantification accuracy within approximately 3% of independently
measured concentration values for scanning conditions that include variation in
the number of acquired counts from one million to several hundred millions and
variation in size and shape from a 20 cm diameter phantom to a tapered phantom
with minimum cross section of 3.7 x 14.5 cm2. This performance is comparable with
that of the 2D acquisition mode.
PMID- 9755950
TI - Mathematical model of the CA1 region of the rat hippocampus.
AB - A mathematical transcription of the intrinsic circuit of the CA1 region of the
rat dorsal hippocampus was made and the model parameters adjusted according to
experimental data from intracellular recordings and single channel kinetics. This
model was able to simulate well the profile of the field potentials recorded
extracellularly and the well known phenomenon of the paired-pulse depression. The
results suggest that the depression of the second pulse, often interpreted in the
literature as resulting from GABA(A) inhibition, can also be due to 'shunting'
effects on the CA1 pyramids' membrane. The rhythmic oscillations of the field
potential (EEG) was obtained as an emergent property of the network dynamics. The
frequency of the field oscillation followed the main synaptic input in the region
(Schaffer collaterals).
PMID- 9755951
TI - Measurement of off-axis and peripheral skin dose using radiochromic film.
AB - A radiotheraphy skin dose profile can be obtained with radiochromic film. The
central axis skin dose relative to Dmax for a 10 x 10 cm2 field size was found to
be 22%, 17% and 15.5% for 6 MV, 10 MV and 18 MV photon beams. Peripheral dose
increased with increasing field size. At 10 MV the skin dose 2 cm outside the
geometric field edge was measured as 6%, 10% and 17% for 10 x 10 cm2, 20 x 20 cm2
and 30 x 30 cm2 field sizes respectively. Off-axis skin dose decreased as
distance increased from central axis for fields with Perspex block trays. For a
20 x 20 cm2 field, an approximately 5-8% drop in percentage skin dose was
observed from central axis to the beam edge.
PMID- 9755952
TI - Dosimetric evaluation of the Siemens Virtual Wedge.
AB - Recently, Siemens has introduced its Virtual Wedge (VW). On a Mevatron
accelerator, this option generates a wedge-like dose profile by moving a
collimator jaw at constant speed while varying the dose rate. In this paper the
formalism is given that is used to deliver a wedge profile and from that the
expressions for possible combinations of wedge angle, field size and delivered
MUs are derived. Also the time needed to deliver a VW field is calculated. An
effective attenuation coefficient mu is used in the implementation. For three
beam energies, values of mu are determined in order to get VW angles that are as
close as possible to the hard wedge angles, over a wide range of field sizes and
wedge angles. Linearity with number of MUs and gantry angle dependence of the
generated dose profiles were checked. These factors did not have a significant
influence on the VW dose profiles. Wedge factors should be close to unity in the
VW implementation. We have measured a number of wedge factors and found that they
start to deviate from 1 with more than 1% for large wedge angles and field sizes,
up to 3.5% for a 19 x 19 cm2, 60 degrees VW field. The Virtual Wedge turned out
to be a reliable tool that can be used clinically, provided that it can be
handled by the treatment planning system. It provides extra flexibility and
usually results in shorter beam on times.
PMID- 9755953
TI - Quality assurance of the dose delivered by small radiation segments.
AB - The use of intensity modulation with multiple static fields has been suggested by
many authors as a way to achieve highly conformal fields in radiotherapy.
However, quality assurance of linear accelerators is generally done only for beam
segments of 100 MU or higher, and by measuring beam profiles once the beam has
stabilized. We propose a set of measurements to check the stability of dose
delivery in small segments, and present measured data from three radiotherapy
centres. The dose delivered per monitor unit, MU, was measured for various
numbers of MU segments. The field flatness and symmetry were measured using
either photographic films that are subsequently scanned by a densitometer, or by
using a diode array. We performed the set of measurements at the three
radiotherapy centres on a set of five different Philips SL accelerators with
energies of 6 MV, 8 MV, 10 MV and 18 MV. The dose per monitor unit over the range
of 1 to 100 MU was found to be accurate to within +/-5% of the nominal dose per
monitor unit as defined for the delivery of 100 MU for all the energies. For four
out of the five accelerators the dose per monitor unit over the same range was
even found to be accurate to within +/-2%. The flatness and symmetry were in some
cases found to be larger for small segments by a maximum of 9% of the
flatness/symmetry for large segments. The result of this study provides the
dosimetric evidence that the delivery of small segment doses as top-up fields for
beam intensity modulation is feasible. However, it should be stressed that linear
accelerators have different characteristics for the delivery of small segments,
hence this type of measurement should be performed for each machine before the
delivery of small dose segments is approved. In some cases it may be advisable to
use a low pulse repetition frequency (PRF) to obtain more accurate dose delivery
of small segments.
PMID- 9755954
TI - Automated detection of BB pixel clusters in digital fluoroscopic images.
AB - Small ball bearings (BBs) are often used to characterize and correct for
geometric distortion of x-ray image intensifiers. For quantitative applications
the number of BBs required for accurate distortion correction is prohibitively
large for manual detection. A method to automatically determine the BB
coordinates is described. The technique consists of image segmentation, pixel
coalescing and centroid calculation. The dependence of calculated BB coordinates
on segmentation threshold was also evaluated and found to be within the
uncertainty of measurement.
PMID- 9755955
TI - The practical implementation of a scatter model for portal imaging at 10 MV.
AB - A detailed validation of a physical model for scattered radiation in portal
images at 10 MV is presented. The ratio of the signal due to scattered radiation
to the signal due to primary radiation (SPR) in an electronic portal image is
defined. A simple physical model for SPR on the central axis (SPR*) was presented
by Swindell and Evans for 6 MV and validated for field sizes up to 320 cm2. In
this paper, the model is extended to 10 MV and validated for field sizes up to
625 cm2. The model is first compared with Monte Carlo modelled data for field
areas A from 40 to 320 cm2, scatterer thicknesses d of 5 to 35 cm water and
scatterer to detector distances L2 of 40 to 100 cm. The physical model has one
free parameter, which is fitted empirically using these data. Second,
experimental measurements are performed with A from 40 to 625 cm2, d from 4.6 to
27.4 cm and L2 fixed at 100 cm. The root mean square (rms) difference between the
physical model and the Monte Carlo calculations was less than 0.001 for all L2
greater than 60 cm. Agreement between experimentally measured and physically
modelled data amounts to a radiological thickness error of at best 0.7 mm in
273.6 mm and at worst 0.4 in 45.6 mm. The model performs equally well at all
field sizes tested. This study shows that the Swindell and Evans SPR* model is
accurate at 10 MV for L2 greater than 60 cm for all A up to 625 cm2.
PMID- 9755956
TI - Influence of background correction in the estimation of myocardial uptake of
99mTc labelled perfusion imaging agents.
AB - The effects of different corrections for background activity in the estimation of
low organ uptake of radiopharmaceuticals have been examined using myocardial
perfusion imaging agents. Estimates of myocardial uptake of 99mTc-labelled MIBI
and tetrofosmin were made both at rest and after exercise. Patients were given
one or other of the agents (12 MIBI; 17 tetrofosmin) and the measurements at rest
and after exercise were made within a week of each other using a planar gamma
camera method incorporating an attenuation-corrected, geometric mean technique.
Myocardial uptakes were estimated using two different background corrections and
also with no background subtraction. Mean values were in the range 1.3 to 3.0%
and showed that, for both agents, uptakes estimated with and without background
correction could differ by a factor of two. Although the study was not designed
to compare myocardial uptakes of the two agents, a background correction which
accounted separately for activity in tissue over- and under-lying the heart
resulted in similar mean values for tetrofosmin (1.7% both at rest and after
exercise) and for MIBI (1.8% rest; 1.9% exercise). For both agents, no
significant difference was observed between myocardial uptakes at rest and after
exercise measured at about two hours post-injection.
PMID- 9755957
TI - Tuberculosis among the disadvantaged. Proceedings of the 3rd annual meeting of
the International Union Against Tuberculosis and Lung Disease, North American
Region. Vancouver, British Columbia, Canada. 26-28 February 1998. Dedicated to
the memory of Professor Stefan Grzybowski.
PMID- 9755958
TI - The challenge of eradication: lessons from past eradication campaigns.
PMID- 9755959
TI - Expanding the WHO tuberculosis control strategy: rethinking the role of active
case-finding.
PMID- 9755960
TI - Tuberculosis in Aboriginals in Canada.
PMID- 9755961
TI - Aboriginal health: not just tuberculosis.
PMID- 9755962
TI - Tuberculosis control among Alaska Native people.
PMID- 9755963
TI - Tuberculosis among the foreign born in Massachusetts, 1982-1994: a reflection of
social and economic disadvantage.
PMID- 9755964
TI - Tuberculosis among the inner city poor.
PMID- 9755965
TI - Case management of tuberculosis in New York City.
PMID- 9755966
TI - Case management: a nursing point of view.
PMID- 9755967
TI - Tuberculosis control in prisons.
PMID- 9755968
TI - Tuberculosis among elderly persons, as observed among nursing home residents.
PMID- 9755969
TI - Lung health and the environment in developing countries.
PMID- 9755970
TI - Principles and priorities in acute respiratory infections in children.
PMID- 9755971
TI - Tuberculosis control in refugees--policy and practices.
PMID- 9755972
TI - Tuberculosis in refugees and displaced persons.
PMID- 9755973
TI - Tuberculosis in health care workers: a multicentre Canadian prevalence survey:
preliminary results. Canadian Collaborative Group in Nosocomial Transmission of
Tuberculosis.
PMID- 9755974
TI - The role of masks in preventing nosocomial transmission of tuberculosis.
PMID- 9755975
TI - The role of ventilation in preventing nosocomial transmission of tuberculosis.
PMID- 9755976
TI - Reducing the impact of tuberculosis transmission in institutions: beyond
infection control measures.
PMID- 9755977
TI - Scientific advances necessary for tuberculosis control.
PMID- 9755978
TI - Prognostic determinants in extrahepatic bile duct cancer.
AB - BACKGROUND/AIMS: The understanding of histopathological prognostic factors is
critical to improving surgical outcome. This study investigated the microscopic
features of cancer of the extrahepatic bile duct in order to clarify the
prognostic determinants affecting surgical outcome. METHODOLOGY: In 90 cancers of
the extrahepatic bile duct, the correlation between several microscopic
parameters and survival was investigated. Lymphatic, venous, and perineural
invasion, and the surgical margin (tumor-free or tumor-positive) were examined
with serial step-wise sectioned specimens. RESULTS: Seven pT1-tumors showed no
venous or perineural invasion and no lymph node involvement and were associated
with prolonged survival (5 year survival, 86%) compared with pT2,3 tumors (23%).
In pT2,3 tumors, lymphatic, venous, and perineural invasion was found in 80%,
47%, and 88%, respectively, with no significant differences in occurrence of
these parameters according to the origin of the primary tumor. As for survival
with pT2,3 tumors, lymph node involvement (58%) and status of the surgical margin
were significant parameters (p=.0330 and p=.0309, respectively). In addition,
these latter parameters differed significantly according to the origin of the
primary tumor. CONCLUSION: In cancer of the extrahepatic bile duct, lymph node
involvement and status of the surgical margin were the most important microscopic
parameters affecting prognosis.
PMID- 9755979
TI - Difficult bile duct stone recurrence after endoscopy and extracorporeal shockwave
lithotripsy.
AB - BACKGROUND/AIMS: In a prospective study, we investigated stone recurrence in high
risk patients with difficult common bile duct stones treated with extracorporeal
shockwave lithotripsy (ESWL) after futile endoscopic attempts at stone extraction
with sphincterotomy. METHODOLOGY: Endoscopic stone extraction proved unsuccessful
in 35 of 659 patients presenting with common bile duct stones (5.5%, 11 males and
24 females: mean age 71.0+/-10.0 yrs; BMI 25.8+/-3.9; ASA-Classification 2.63+/
0.65), due to large stone size (10 patients), incarcerated stones (15 patients),
stones inaccessible to the Dormia basket (7 patients) or an impacted Dormia
basket (3 patients). The stones were localized radiologically. ESWL was performed
using the HM3 lithotripter (Dornier, Munich/FRG). RESULTS: Immediately following
ESWL, 17.1% of the patients treated showed complete stone clearance. In an
additional 57.1%, further endoscopic stone extraction was required to achieve
complete stone clearance, while 20.0% were discharged with small residual stone
fragments. The remaining 2 patients (5.7%) required surgical intervention. Thirty
four of 35 patients (97.1%) were followed-up for an average of 27+/-11 months.
Five patients (14.3%) experienced stone recurrence at an average of 13.8+/-5.7
months post ESWL. CONCLUSIONS: ESWL is a useful and safe adjunct to endoscopic
management of difficult common bile duct stones in older, high-risk patients. The
stone recurrence rate was about 14% after one year. All recurrent stones were
treatable by endoscopy.
PMID- 9755980
TI - The role of juxtapapillary duodenal diverticulum in the formation of gallbladder
stones.
AB - BACKGROUND/AIMS: Juxtapapillary diverticula (JPD) are considered to be associated
with choledocholithiasis but not with cholecystolithiasis. However, there have
been few comparative studies on the relationship between JPD and
cholecystolithiasis under strict matching for sex and age. METHODOLOGY: Among
4542 consecutive ERCPs at Tokyo Metropolitan Komagome Hospital, 549 patients who
were 63 years of age or older were enrolled in this study and were matched for
sex and age. They were divided into two groups: with and without JPD. Firstly,
the frequency of cholecystolithiasis was compared between the two groups. Next,
we recruited 83 patients whose JPD size could be measured by the ERCP films and
investigated the relationship between JPD size and gallstones. RESULTS: We found
no correlation between JPD and the overall frequency of cholecystolithiasis.
However, an analysis of 83 patients with measurable JPD revealed that the size of
JPD was closely linked to the occurrence of cholecystolithiasis. The JPD size was
statistically larger in patients with cholecystolithiasis than those without.
Moreover, when the mean diameter of JPD was 20 mm or more, the incidence of
cholecystolithiasis rose up to 73.3%, which was significantly greater compared to
the incidence in patients without JPD (p< 0.05). CONCLUSION: A larger JPD may
play a role in the formation of gallbladder stones.
PMID- 9755981
TI - Concurrent primary carcinoma of the gallbladder and acute cholecystitis.
AB - BACKGROUND/AIMS: Primary carcinoma of the gallbladder is rare and associated with
a late diagnosis and poor prognosis. Concurrent acute cholecystitis frequently
obscures the presence of carcinoma. The information regarding gallbladder
carcinoma with acute cholecystitis is limited. In order to better understand the
presentation of gallbladder carcinoma with acute cholecystitis, we
retrospectively reviewed the data of patients with primary carcinoma of the
gallbladder. METHODOLOGY: The data of 86 patients with primary carcinoma of the
gallbladder treated between 1979 and 1994 were compiled and reviewed. The
patients were divided into 2 groups: Group 1 (with acute cholecystitis, 21
patients) and Group 2 (without cholecystitis, 65 patients). Clinicopathological
comparisons were made and evaluated between these two groups RESULTS: The average
age of Group 1 patients was older than that of Group 2 patients (75+/-2 years vs.
63+/-2 years; p<0.05). Three Group 1 patients presented with sepsis. The interval
between the onset of symptoms and hospital admission in Group 2 patients was
significantly (p<0.05) longer than that in Group 1 patients (243+/-95 days vs.
20+/-11 days). Leukocytosis (>11,000/mm3) was more common in Group 1 patients
than in Group 2 patients (47.6% vs. 15.4%). Jaundice was more common in Group 2,
and fever was common in Group 1. The majority of Group 2 gallbladder cancers were
stage V (75.4%). In contrast, 52.4% of Group 1 gallbladder cancers were stage III
and 38.1% were stage V. The 30-day postoperative mortality rate in Group 1 and
Group 2 patients was 9.5% and 7.7%, respectively. The cumulative survival of
Group 1 patients was not different from that of Group 2 patients (log-rank test,
p>0.05). CONCLUSIONS: Age, the interval of symptoms prior to admission, the
location of abdominal pain, fever, leukocytosis, and the absence of jaundice
suggested the presence of acute cholecystitis in gallbladder carcinoma. A high
index of suspicion of the disease, intraoperative examination of gallbladder
specimens, and more aggressive surgical treatment may improve patient survival.
PMID- 9755982
TI - Gallbladder cancer with intratumoral anechoic foci: a mimic of adenomyomatosis.
AB - We report a case of advanced gallbladder cancer in a 58-year-old man. On
ultrasonography, there were anechoic foci within the tumor. Although anechoic
foci within a thickened gallbladder wall usually represent intramural diverticula
(dilated Rokitansky-Aschoff sinuses) of adenomyomatosis, cystically dilated
cancerous glands were the etiology of these foci in this case. Thus, gallbladder
cancer may also have anechoic foci within the tumor.
PMID- 9755983
TI - Cutaneous metastatic adenocarcinoma of gallbladder origin: report of a case and
review of the literature.
AB - In the English literature, there have only been seven reports of metastasis from
cancer of the gallbladder to the skin. This is the report of a 75-year-old woman
who developed cutaneous metastasis from an adenocarcinoma of the gallbladder
which was confirmed histologically. We report the uncommon metastatic potential
of gallbladder carcinoma to the skin.
PMID- 9755984
TI - Ascariasis of the alimentary tract, liver, pancreas and biliary system: its
diagnosis by ultrasonography.
AB - BACKGROUND/AIMS: The purpose of this study was to describe the echographic
features of Ascaris lumbricoides invasion of the alimentary tract, biliary
system, liver and pancreas. METHODOLOGY: We studied 38 patients with roundworm
heavy infection whose diagnosis were primarily supported by ultrasonographic
examination. RESULTS: Thirty-seven patients were admitted with the following
clinical complications: bowel obstruction, intra and extrahepatic dilatation,
acute cholecystitis, intrahepatic abscess, acute appendicitis, subphrenic
collection and acute pancreatitis. Ultrasound scanning was able to recognize in
30 cases the echogenic, nonshadowing images of the worms as single or multiple
strips; in 8 cases, coiled structures and amorphous material were detected. The
"inner tube" sign was considered as the most specific one. In two cases the
roundworms were displayed within the stomach, a curious finding, up to now never
reported in medical literature. CONCLUSIONS: Real-time sonography represents an
efficient, reliable and non-invasive diagnostic approach for hepatobiliary,
enteric and pancreatic ascariasis.
PMID- 9755985
TI - Endoscopic ultrasonography in the evaluation of leiomyoma and extramucosal cysts
of the esophagus.
AB - BACKGROUND/AIMS: Leiomyoma is the most common type of benign esophageal tumor,
whereas extramucosal cysts of the esophagus are congenital anomalies frequently
asymptomatic in the adult and in most cases detected incidentally on chest x-ray.
It is worthwhile considering these conditions together, because they present
similar diagnostic and surgical problems. Conventional imaging tests do not lead
to a precise diagnosis. The purpose of this study was to evaluate the use of
endoscopic ultrasonography in the diagnosis of, and planning of treatment
modalities for, these conditions. METHODOLOGY: Fifteen patients with esophageal
leiomyoma and seven patients with extramucosal esophageal cysts were studied with
endoscopic ultrasonography using an Olympus GF- EU-M3 instrument with a 7.5-12
MHz echoprobe. In all patients, the results of endoscopic ultrasonography were
compared with the histology of the resected specimens. RESULTS: The histology of
the resected specimens confirmed the endosonographic diagnosis in all patients.
No malignancy was found in any specimen. CONCLUSIONS: Endoscopic ultrasonography
is very accurate in visualizing these lesions and differentiating cystic from
solid submucosal esophageal masses; in addition, the test can establish the exact
location of the mass in relation to the esophageal wall and mediastinum.
Therefore, endoscopic ultrasonography has a great impact in confirming the
diagnosis of leiomyoma and extramucosal cysts of the esophagus and facilitates
therapeutic decision-making because of its capacity to clearly define the size,
layer of the origin, and pattern of the mass.
PMID- 9755986
TI - An immunohistochemical study of E-cadherin expression with correlations to
clinicopathological features in gastric cancer.
AB - BACKGROUND/AIMS: Reduced expression of E-cadherin leading to loss of cellular
adhesion is crucial for cancer invasion and metastasis. The aim of this study is
to investigate the role of E-cadherin in gastric tumorigenesis. METHODOLOGY:
Immunohistochemical expression of E-cadherin was analyzed and correlated with
clinicopathological characteristics of 122 patients with gastric cancer. RESULTS:
Reduced E-cadherin expression was noted in 71 tumors (58.2%), while all normal
epithelium showed a normal expression. Correlation of E-cadherin status to
histological subtypes and growth patterns revealed a significantly higher
frequency of reduced expression in diffuse type (46/60, 76.7%), advanced tumors
(48/68, 70.6%) and stage III/IV (39/53, 73.6%) than that in intestinal type
(25/62, 40.3%, p<0.0001), early tumors (23/54, 42.6%, p<0.005) and stage I/II
(32/69, 46.4%, p<0.005) respectively. Moreover, abnormal expression was more
frequent in tumors with positive lymph node metastasis (45/62, 72.6%), peritoneum
seeding (10/11, 90.9%) and venous permeation (27/37, 73%) than that in tumors
without lymph node metastasis (26/60, 43.3%, p<0.005), peritoneum seeding
(61/111, 55.0%, p<0.05) and venous permeation (44/85, 51.8%, p<0.05). There is no
statistical difference between E-cadherin expression and the status of perineural
invasion or H. pylori infection. Analysis of survival for patients demonstrated
that reduced E-cadherin expression was correlated with poor prognosis.
CONCLUSIONS: These data indicate that impaired expression of E-cadherin is an
important characteristic of gastric cancer and contributes to histogenesis, tumor
growth, metastasis and poor survival.
PMID- 9755987
TI - A new preoperative immunochemotherapy for the treatment of locally advanced
esophageal cancer.
AB - A promising preoperative immunochemotherapy regimen for locally advanced
esophageal cancer is herein described. A 67-year-old man suffering from severe
dysphagia was diagnosed with unresectable esophageal cancer at initial
examination because of a tumor of 11 cm in length and suspicion of trachea
invasion. Neoadjuvant immunochemotherapy was undertaken for the down-staging.
Interleukin-2 (IL-2) (3.5 x 10(5) Japan reference units), nedaplatin (7 mg/m2)
and 5-FU (300 mg/m2) were administered intravenously daily for 5 days a week for
three weeks. The gross findings of a barium esophagogram and esophagoscopy
revealed significant tumor regression in both size and shape. The patient
underwent an esophagectomy through a laparotomy followed by a right thoracotomy.
The surgical specimens were serially sectioned and examined microscopically. All
of the surgical margins were clear (upper and lower margins as well as the
adventitia), and there was no evidence of lymph node metastasis. The surgical
specimen revealed neoplastic squamous ghost cells surrounding significant
lymphocyte infiltration. This appears to be a unique feature of this particular
neoadjuvant immunochemotherapy.
PMID- 9755988
TI - Two cases of gall bladder agenesis and review of the literature.
AB - Two patients with agenesis of the gall bladder are reported herein, and the
relevant literature reviewed. It is important to be aware of this condition as
patients often present with symptoms of gall bladder disease, which may lead to
confusion at laparoscopic cholecystectomy.
PMID- 9755989
TI - The relation between irregular bowel movement and the lifestyle of working women.
AB - BACKGROUND/AIMS: It is said that constipation is related to the occurrence and
increase of bowel disease and colon cancer; however, there are few reports on
this subject, and information about bowel movements in connection with the
lifestyles of working women are almost non-existent. METHODOLOGY: We conducted a
survey of working women and obtained 509 valid responses. The odds ratios of the
following factors were calculated: the number of bowel movements, skipping
breakfast, dieting, suppressing bowel movements, haemorrhoids (anal fistulae),
and stress. RESULTS: The prevention of skipping breakfast and suppressing bowel
movement had a big effect on the increase of bowel movements and in preventing
constipation, especially when the two factors were combined. For those
experiencing haemorrhoids, stress had a great influence. More than half of the
respondents admitted that the first appearance of the signs of constipation was
during their high school days or before. The peculiar sense of shame of women in
their adolescence, the disorder of daily life, the desire to obtain a slim figure
and stress are thought to be triggers for the problem of constipation.
CONCLUSIONS: It is clear that the four factors in daily life defined above can
have significant influence on constipation in women. It is thought that a proper
diet with the right guidance, as well as social considerations can have
favourable effects on these factors.
PMID- 9755990
TI - Surgery for ulcerative colitis in Greece: clinicoepidemiological features and
long-term outcome of 69 consecutive patients.
AB - BACKGROUND/AIMS: In this study, the various clinicoepidemiological
characteristics and long-term follow-up of patients operated on for ulcerative
colitis in Greece over a period of 15 years, are reviewed. METHODOLOGY: A total
number of 69 out of 413 patients with ulcerative colitis (17.8%) seen and
followed-up for a mean period of 12 years, had undergone ileorectal anastomosis
(45.6%), total proctocolectomy with permanent ileostomy (35.6%), ileal-anal pouch
anastomosis (17.6%) and Kock ileostomy (1.5%), mainly for bad response to
conservative treatment (78.3%). Other causes for operation were large bowel
cancer (8.7%), profound hemorrhage (4.3%), toxic megacolon (1.4%), and
rectovaginal fistula (1.4%). Almost half of the operations (45%) were performed
between the first and fourth year after the establishment of diagnosis. RESULTS:
A number of statistically highly significant differences between the operated and
non-operated group of patients were noticed. So, patients operated on had more
extensive disease in comparison with non-operated ones and were younger at the
time of diagnosis. The overall perioperative morbidity and mortality were 6% and
5% respectively. Survival was not statistically significantly different between
operated and non-operated patients and also did not differ significantly between
men and women. Most of the deaths in the operated and non-operated group of
patients were unrelated to ulcerative colitis. CONCLUSION: It is concluded that
the clinicoepidemiological features and outcome of the Greek patients operated on
for ulcerative colitis have similarities with those reported from other developed
countries of the world.
PMID- 9755991
TI - Circular hemorrhoidectomy in advanced hemorrhoidal disease.
AB - BACKGROUND/AIMS: Milligan-Morgan's hemorrhoidectomy has a high recurrence rate (>
10%) in patients with circular IV grade hemorrhoids. In such cases a circular
hemorrhoidectomy with complete elimination of residual piles, and anoplasty might
be more successful. The aim of this retrospective study was to compare the
results of circular hemorrhoidectomy using the Hopital Leopold Bellan (HLB)
technique (Paris) with the reported results of other techniques in patients with
advanced hemorrhoidal disease. METHODOLOGY: From January 87 to December 96, 100
consecutive patients with circular IV grade hemorrhoids underwent radical
hemorrhoidectomy. Mean hospital stay was 4 days (range 3-7). Patients were
strictly controlled in the postoperative period and in cases of early fibrosis
anal dilators were used. RESULTS: Eighty one percent of patients had a complete
recovery. The recurrence rate was 4%. The cumulative rate of early and late
complications was 34%. Early and late hemorrhages were more frequent than in
traditional hemorrhoidectomy, while the incidence of anal stenosis was the same.
CONCLUSIONS: The HLB operation is the best choice for patients with advanced
circular hemorrhoids because of its radicality and good results. The
postoperative morbidity of HLB hemorrhoidectomy is higher than traditional
hemorrhoidectomy; nevertheless, all complications are tractable without extension
of hospital stay.
PMID- 9755993
TI - Surgery in Crohn's disease: when, where and why the recurrences?
AB - One frustrating feature in the surgical management of Crohn's disease is the high
recurrence rate which may lead to reoperation. It is common opinion that relapses
occur haphazardly both in time and in site, and the causes remain unknown. When
does a recurrence really arise after surgery? Is the site of recurrence
determined by definite causes? Is there a relapsing factor? Between 1965 and
1995, 177 patients underwent surgery for Crohn's disease. The procedures
performed in 145 cases were those popular at the time, while a recent series of
20 selected patients was managed following a new approach based on
epiploonplasty. This strategy stems from the strong conviction that Crohn's
disease is not a primary bowel disease but the result of stasis and superimposed
infection due to a primary hemolymphatic disorder of the mesentery. The five-year
recurrence rate was 62% in patients operated on according to standard procedures,
while no recurrences were reported in the epiploonplasty group. Among 12
remaining patients with recurrent disease, two cases are reported in detail
because they provide evidence in favor of the hemolymphatic theory. This study
also maintains that recurrences, viewed with the hemolymphatic disorder in mind,
occur immediately after surgery, while the superimposed intestinal inflammatory
process and stricturing events may appear clinically at different time intervals
during follow-up. The site of recurrences usually corresponds to the mesenteric
region subjected to compression. Altered mesenteric microcirculation appears to
be the true essence of the disease.
PMID- 9755992
TI - Retroperitoneal fibrosis: unusual localization.
AB - Six cases of retroperitoneal fibrosis, each with a different pathogenesis and
unusual localization were observed from 1980 to 1996. Four patients had had
previous surgery for a neoplasm, one patient had idiopathic retroperitoneal
fibrosis, and the last patient was hardly classifiable due to the complexity of
the clinical pattern. The mean survival in 3 patients with malignant
retroperitoneal fibrosis was 7 months. Two patients treated with medical therapy
are still alive and in good clinical condition. The aspecificity of the symptoms
makes early diagnosis difficult. CT and NMR are essential procedures for
differential diagnosis of abdominal masses. Histology differentiates benign from
malignant retroperitoneal fibrosis. The choice between medical or surgical
therapy depends on the general condition of each patient.
PMID- 9755994
TI - Gamma-glutamyl transferase, intestinal alkaline phosphatase and beta
hexosaminidase activity in duodenal biopsies from chronic alcoholics.
AB - BACKGROUND/AIMS: Gamma-glutamyl transferase (GGT) and intestinal alkaline
phosphatase (IAP) are present in the brush border of mucosal absorptive cells in
the small intestine. There are few studies on the effect of alcohol consumption
on these enzymes. Increased intestinal GGT in biopsy specimens from the duodenum
has been described in chronic alcoholics. In experimental animals alcohol effects
varies with duration of exposure and with nutritional factors. METHODOLOGY: IAP,
GGT and the lysosomal enzyme beta-hexosaminidase (Hex) were examined in duodenal
biopsy specimens from 23 defined chronic alcoholics and 33 non alcoholic
controls. The results were correlated to serum GGT, alkaline phosphatase, CDT
(Carbohydrate Deficient Transferrin) and the villus index. RESULTS: Both the
intestinal GGT (0.52 + 0.05 SEM vs. 0.30 + 0.024 SEM microkat/g protein,
p<0.0001) and the IAP (22.11 + 2.49 SEM vs. 12.28 + 1.35 SEM microkat/g protein,
p=0.0010) were significantly higher in alcoholics than in controls. There was no
correlation between intestinal and serum alkaline phosphatase and GGT activity
within the two groups. CONCLUSIONS: Chronic alcohol consumption causes increased
intestinal GGT and IAP activity in man. No effect on Hex was seen. The enzyme
activity in the small intestine did not correlate to serum enzyme activity or to
morphological changes in the small intestine.
PMID- 9755995
TI - Continuous maintenance with low-dose lansoprazole versus Helicobacter pylori
eradication in the prevention of duodenal ulcer recurrence.
AB - BACKGROUND/AIMS: Reduction of gastric acid secretion by maintenance treatment
with antisecretory agents and eradication of H. pylori by antibiotics constitute
the most effective therapeutic options in preventing duodenal ulcer relapse. The
aim of this study was to compare the effect of a 12-month low-dose lansoprazole
maintenance treatment with H. pylori eradication on the rate of ulcer relapse in
H. pylori-positive duodenal ulcer patients. METHODOLOGY: After a healing phase
with lansoprazole 30 mg/die or lansoprazole 30-60 mg/die plus antibiotics
(amoxycillin, tinidazole and colloidal bismuth subcitrate), 84 patients with
healed duodenal ulcer entered the follow-up phase. Thirty-eight patients with
persistent H. pylori infection received lansoprazole 15 mg at bedtime, whereas 46
in whom H. pylori was eradicated during the acute phase received no active
therapy during the 12-month follow-up. The two groups were well balanced
concerning all demographic characteristics. Clinical controls were performed
every 3 months or sooner in the event of symptomatic relapse. RESULTS: In terms
of per protocol analysis, the overall rate of ulcer relapse at 6 months was 5.5%
(2/36) in the maintenance group and 0 (0/42) in the antibiotic group. The
corresponding figures at 12 months were 20.5% (7/34) and 5.7% (2/35),
respectively (p:ns, 95% CI for the difference -0.30+0.02). On intent to treat
analysis, the rate of ulcer relapse at 6 months was 5.2% (2/38) in the first
group and 0% (0/46) in the second group: at 12 months the corresponding figures
were 19.4% (7/36) and 4.3% (2/46), respectively (p=0.06; CI 95%: +0.016+0.28). No
significant side effects were observed during long-term maintenance with
lansoprazole. CONCLUSIONS: Continuous maintenance with low-dose lansoprazole may
constitute a valuable alternative to H. pylori eradication for the prevention of
relapse and complications in duodenal ulcer patients not suitable for, or who
have failed, H. pylori eradication.
PMID- 9755997
TI - The effects of omeprazole, a proton pump inhibitor, on early gastric stagnation
after a pylorus-preserving pancreaticoduodenectomy: results of a randomized
study.
AB - BACKGROUND/AIMS: To determine the effects of Omeprazole, a proton pump inhibitor
(PPI), on gastric stasis following a pylorus-preserving pancreatico-duodenectomy
(PPPD) by means of a randomized trial of PPPD patients. METHODOLOGY: Forty-two
PPPD patients were randomly divided into two groups: Group 1 (n=24) received a
PPI through a jejunal tube after PPPD, whereas Group 2 (n=18), serving as
controls, received a saline solution through a jejunal tube and no medication
after a PPPD. The daily volume and total acidity of the gastric juice, aspirated
via nasogastric tube, were measured each day for 7 days following PPPD. RESULTS:
In Group 1 the mean daily aspirated volume of gastric juice was 160.2 ml, and the
mean maximum volume was 222.8 ml on the first postoperative day. In Group 2, six
patients were withdrawn from this study for therapy on the third or fourth
postoperative day due to gastric bleeding and/or a large amount of excreted
gastric juice (in excess of 2,000 ml). The mean daily aspirated volume of gastric
juice in the remaining Group 2 patients was 787.4 ml, and the mean maximum volume
was 1,039 ml on the third postoperative day. Gastric secretion was significantly
lower in Group 1 (p<0.05). Further, the total acidity of the gastric juice was
significantly lower in Group 1 than in Group 2 for each of the 7 postoperative
days (p<0.05). CONCLUSIONS: These results indicate that postoperative
administration of a PPI significantly suppresses the volume and acidity of the
gastric juice after PPPD.
PMID- 9755996
TI - Prognostic relevance of histomorphological parameters and DNA content and their
therapeutic consequences in esophageal carcinoma: a multivariate approach.
AB - BACKGROUND/AIMS: Despite recent advances in surgical and multidisciplinary
treatment, the prognosis for patients with esophageal carcinoma remains poor. The
low prognostic accuracy of even surgical pathological TNM staging suggests that
additional parameters would be useful in determining the prognosis. METHODOLOGY:
We undertook a retrospective analysis of 115 patients who had undergone
transhiatal and transthoracic esophageal resection due to squamous cell carcinoma
of the esophagus. In addition to TNM classification and the usual morphological
criteria, a quantitative DNS analysis using Image DNA cytometry was performed. At
the time of DNA analysis, histomorphological parameters and survival time was not
known. RESULTS: The main prognostic parameter was the curativity (R
classification) of the operation. Using only patients who had had R0 resection, a
multivariate analysis was performed. Parameters included: patient age;
preoperative ASA classification; tumor localization; pN category; number of intra
thoracal lymph nodes removed; pT category; pM category; grading; lymphangiosis;
ploidy; operative procedure, and the development of postoperative complications
identifying the ploidy, and the depth of tumor infiltration of prognostically
independent factors. CONCLUSIONS: In the case of a diploid or tetraploid DNA
content, tumor resection is recommended even in the case of lymph node metastasis
at the truncus coeliacus. Patients with a diploid or tetraploid tumor without
distant metastasis and tumor stage pT1-pT3 may, after curative (RO) transthoracic
resection with two-field lymph node dissection, have an advantage over patients
having a transmediastinal procedure in terms of long-term follow up. In cases of
aneuploid DNA content, tumor resection shows no advantage over palliative non
operative procedures. Preoperative radio- or chemotherapy may improve the
prognosis of these patients.
PMID- 9755998
TI - Blood transfusion and postoperative serum interleukin-6 levels in colorectal
cancer patients.
AB - BACKGROUND/AIMS: Postoperative cytokine response affects various factors.
However, excessive stress responses are deleterious as increased serum
concentration of cytokines may induce tissue injury and an impaired immune
system. METHODOLOGY: We determined serum IL-6 levels in 35 patients who had
undergone resection of colorectal carcinoma. Eleven patients had a blood
transfusion before or during the operation (transfused group) but 24 patients had
received no blood transfusion (control group). Serum IL-6 levels were determined
before the operation, and at the end of operation,POD-1, 3, and 7. RESULTS: There
was no significant difference of preoperative mean levels of IL-6 between these
two groups (p=0.20). Postoperative serum IL-6 levels were significantly elevated.
Mean serum levels of IL-6 were significantly higher at the end of operation in
the transfused group than in the control group (131.7 pg/ml in control group and
269.8 pg/ml in transfused group; p=0.02). CONCLUSION: The present study suggested
that perioperative allogeneic blood transfusion can induce an excessive cytokine
response and may be deleterious.
PMID- 9755999
TI - Mini-laparoscopic cholecystectomy.
AB - BACKGROUND/AIMS: The authors describe their experience in performing
cholecystectomy using mini-laparoscopy in selected cases of uncomplicated
cholelithiasis. This involved making one 10 mm, one 5 mm and two 2 mm incisions.
METHODOLOGY: From July 1996 to August 1997, 60 cholecystectomies were performed
using mini-laparoscopy, out of a total of 203 video-laparocholecystectomies
performed during the same period. RESULTS: Average length of the operations was
36 minutes from insertion of the first trocar to extraction of the gallbladder.
All patients were discharged in the second day after surgery. No short-term intra
or post- operative complications occurred. CONCLUSIONS: The benefits of mini
cholecystectomy are potential advantages in improved appearance, reduced pain,
better respiratory function, fewer wall complications. Therefore, the authors
believe that mini-laparoscopy should not be assessed in terms of percentage of
use or success, but rather considered as a part of the laparoscopic method to be
used in selected cases.
PMID- 9756000
TI - Diagnosis of small intestinal bacterial overgrowth in clinical praxis: a
comparison of the culture of small bowel aspirate, duodenal biopsies and gastric
aspirate.
AB - BACKGROUND/AIMS: This study was undertaken to validate the usefulness of the
culture of duodenal biopsy specimens and gastric aspirate compared to the culture
of small bowel aspirate for diagnosing small intestinal bacterial overgrowth. We
also investigated the occurrence of predisposing conditions in these patients.
METHODOLOGY: Seventy five consecutive patients, admitted because of symptoms
which caused us to suspect small intestinal bacterial overgrowth, were studied.
For all patients, specimens for the culture of small bowel aspirate, duodenal
biopsies and gastric aspirate were obtained during upper endoscopy. RESULTS:
Eighteen patients showed growth of gram negative bacteria, 22 growth of gram
positive bacteria and 35 showed no significant growth in cultures of small bowel
aspirate. Cultures of duodenal biopsies revealed gram negative bacteria in 11
patients, gram positive bacteria in 9 and no growth in 55. Cultures of gastric
aspirate revealed gram negative bacteria in 7 patients, gram positive bacteria in
12 and no growth in 51. Ten of the 18 patients with gram negative overgrowth and
13 of the 22 patients with gram positive overgrowth had a predisposing condition.
In contrast, only 4 of the 35 without overgrowth had a predisposing condition.
CONCLUSIONS: The culture of duodenal biopsy specimens or gastric aspirate is a
less sensitive method than the culture of small bowel aspirate. Most patients
with culture-proven small intestinal bacterial overgrowth had at least one
predisposing condition.
PMID- 9756001
TI - Effect of clonidine on gastrointestinal transit time.
AB - BACKGROUND/AIMS: Orocecal time can be measured by lactulose H2 breath test.
Duodenal entry time can be evaluated by measuring D-xylose; the duodeno-cecal
time can be derived by subtracting duodenal entry time from orocecal time. In
this study we established the normal value of these parameters for our laboratory
in males and also evaluated the effect of clonidine on these parameters.
METHODOLOGY: In 9 healthy male volunteers orocecal time was measured by the
lactulose H2 breath test. Duodenal entry time was established by measuring blood
D-xylose. Duodenocecal time was derived by subtracting duodenal entry time from
orocecal time. RESULTS: The mean orocecal time was 54.44 + 3.77 minutes; the mean
duodenal entry time was 17.22 + 3.15 minutes and the mean duodenocecal time was
37.22 + 3.16 minutes. CONCLUSIONS: Oral clonidine prolonged orocecal, duodenal
entry and duodenocecal times in only 33% of the subjects.
PMID- 9756002
TI - Effects of intraoperative blood transfusion on postoperative complications and
survival after orthotopic liver transplantation.
AB - BACKGROUND/AIMS: Massive blood transfusion related to the coagulation disorders
occurring during the anhepatic and reperfusion phases, remains a serious problem
during orthotopic liver transplantation. To analyze the influence of
intraoperative blood transfusion on postoperative complications, and survival and
to identify the preoperative variables associated with greater intraoperative
bleeding, 100 orthotopic liver transplantations, carried out on adults, were
reviewed in our center. METHODOLOGY: Patients were grouped into three categories
according to intraoperative blood volume transfused; group A, 1.5 or less blood
volumes transfused; group B, > 1.5 and < 3 volumes used and group C, 3 or more
volumes given. RESULTS: Group C patients had a higher incidence of upper
abdominal surgery (p < 0.01 between groups C and A. and p<0.05 between groups C
and B); higher values of postoperative total bilirubin and SGOT, and lower
prothrombin activity. Acute rejection and steroid-resistant episodes per patient
occurred less commonly (p <0.01 between groups C and A) and so did chronic
rejection (p <0.05 between groups C and B). Higher infection rate, and
gastrointestinal and intraabdominal complication rates were also noticed in
groups C and B (p < 0.01 and p < 0.05 respectively). Patient survival rates were
lower in group C (p < 0.05 between groups C and A). CONCLUSIONS: It was concluded
that previous upper abdominal surgery was the only preoperative factor associated
with massive blood transfusion. Poor graft function during the first days after
transplant, higher incidence of infections, higher incidence of gastrointestinal
and intraabdominal complications, and lower rejection episodes and survival for
patients receiving intraoperatively large amounts of blood can be expected.
PMID- 9756003
TI - Resectional liver surgery in metastatic liver disease.
AB - BACKGROUND/AIMS: To increase resectability rate and decrease intra-hepatic
recurrence of metastatic liver disease of patients suffering from secondary liver
tumors. Metastatic liver disease remains challenging and life threatening. At the
time of diagnosis only 10% of patients are amenable to liver resection and of
those 60-70% will develop recurrence in the residual liver 16 to 24 months
following liver resection METHODOLOGY: Seventy patients out of a total number of
305 seen between November 1991 and May 1998, underwent combined liver resection
followed by adjuvant locoregional targeted immunochemotherapy. Patients were
divided in two groups. Group A (n=32) had uni-lobular localization of their
disease and group B (n=38) had bi-lobular spread of the disease, but tumor
occupied was less than 70% of liver surface. All had hepatic resection followed
by adjuvant immuno-chemotherapy. RESULTS: Group A (n=32) had a 5 year survival of
75% with 8 patients alive more than 6 years and a mean survival for alive and
dead patients of 50 months. Group B (n=38) had a mean survival of 40 months with
6 patients alive longer than 5 years. CONCLUSIONS: Liver resection combined with
adjuvant immuno-chemotherapy enhances overall long-term survival in both patients
with limited and advanced metastatic liver disease, and is recommended as a
promising therapeutical alternative.
PMID- 9756004
TI - Liver transplantation: problems and perspectives.
AB - Orthotopic liver transplantation (OLT) has made remarkable advances. However,
results vary according to the etiology and the severity of the liver disease.
Shortage of donors is becoming an increasing problem because results are
improving, more centers are embarking on transplantation and because the
indications become wider. Measures have to be taken to improve the number of good
donor livers and the condition of the recipient.
PMID- 9756005
TI - The importance of initial daily administration of interferon alpha for the
eradication of hepatitis C virus in patients with chronic hepatitis C: a
multicenter randomized trial.
AB - BACKGROUND/AIMS: We studied the effect of initial daily administration of
interferon for the treatment of chronic hepatitis C, to clarify a more effective
treatment protocol for the eradication of the hepatitis C virus. METHODOLOGY:
Consecutive patients who met the inclusion criteria were randomly enrolled in two
groups in this study. One hundred and five patients were randomized and assigned
to two groups. Patients, who enrolled in group A, were treated with 6 million
units of natural interferon-alpha given subcutaneously daily for an initial two
weeks and then thrice a week for 22 weeks. Patients, who were enrolled in group
B, were treated with the same dose of interferon-alpha given for 26 weeks thrice
a week from the first administration. RESULTS: In groups A and B, 58 and 47
patients were analyzed, respectively. At the end of treatment, 37 patients in
group A (63.8%) had negative serum HCV-RNA test, compared with 26 in group B
(55.3%), but at 6 months after discontinuation of interferon administration, 27
patients in group A (46.6%), compared with 8 in group B (21.3%). The rate of
complete remission in group A (46.6%) was higher than that in group B (21.3%)
(P<0.01). In patients with genotype 1b virus, the rate of complete remission was
higher in group A (31.3%) than in group B (12.5%) (not significantly), and the
relapse rate was lower in group A (9.4%) than in group B (37.5%), significantly
(p<0.05). CONCLUSIONS: This study suggests that initial daily interferon
administration is necessary to gain a higher rate of serum HCV-RNA eradication in
patients with chronic hepatitis C.
PMID- 9756006
TI - Effects of matrix metalloproteinase inhibitor BB-94 on liver cancer growth and
metastasis in a patient-like orthotopic model LCI-D20.
AB - BACKGROUND/AIMS: The aim of this study was to try to understand the effects of
the synthetic matrix metalloproteinase inhibitor Batimastat (BB-94) on
hepatocellular carcinoma (HCC). METHODOLOGY: An orthotopic metastatic human
hepatocellular carcinoma in nude mice model (LCI-D20) was used to study primary
tumor growth, local invasion and metastasis of HCC. MTT assay was used to study
the effects of BB-94 on cytotoxin and proliferation of HCC cell line SMMC-7721 in
vitro. A gelatine zymograph was used to study the expression of MMPs in the LCI
D20 tumor tissue. RESULTS: BB-94 can inhibit primary tumor growth, local
invasion, intrahepatic and lung metastasis, as well as prolong survival. BB-94
did not affect the proliferation of HCC cells in vitro. LCI-D20 tumor tissue
expresses MMP-2 and MMP-9. CONCLUSIONS: BB-94 has a cytostatic therapeutic effect
on HCC.
PMID- 9756007
TI - Perihepatic lymphadenopathy: a marker of response to interferon alpha in chronic
hepatitis C.
AB - BACKGROUND/AIMS: Recently it was shown that perihepatic lymphadenopathy (PHL)
correlates with histological activity in chronic hepatitis C. However, the
question whether there is a correlation between the response to interferon alpha
and PHL has not yet been raised. METHODOLOGY: We examined 103 patients who had
been treated with interferon alpha for hepatitis C. Prior to treatment all
patients had undergone high resolution ultrasonography. Thirty-six patients had
follow up ultrasound scans during the course of the treatment. According to size
and number of lymph nodes we introduced a grading of the PHL and determined grade
I as minimal, grade II as medium and grade III as extensive PHL. RESULTS:
Classification of PHL prior to treatment revealed 40 patients with PHL I, 30 with
grade II and 33 with grade III. Hepatic inflammatory activity according to the
Ishak score was increased in patients with PHL III (9.1+/-2.4) compared to PHL II
(6.7+/-2.9) and PHL I (7.3+/-3.1) (p=0.01). In patients with PHL grade I prior to
treatment 45% were initial responder, patients with grade II or III showed
response rates of 40% and 33%, respectively. During therapy we found an increase
of PHL in one out of 13 primary responder vs. 10 out of 23 non-responder
(p=0.03). CONCLUSIONS: In conclusion, monitoring of PHL by abdominal
ultrasonography is a simple, non-invasive and cheap additional marker of response
to interferon alpha.
PMID- 9756008
TI - Liver volume in patients with or without chronic liver diseases.
AB - BACKGROUND/AIMS: The size of the liver is an important clinical parameter; the
aim of this study is to examine the correlation between liver volume and etiology
and the severity of disease, and to evaluate its usefulness in predicting
survival. METHODOLOGY: Patients observed in this study were comprised of thirty
three patients with non-liver disease and 44 patients with chronic liver disease
(alcoholic hepatitis, 9; hepatitis B, 24; and hepatitis C, 11). The liver volume
was measured from digitized CT scan images. Techniques of planimetry and
summation of areas were utilized for calculation. RESULTS: The prediction model
to estimate liver volume in patients without liver disease was: liver volume
(ml)= [13 x height (cm)] +[12 x weight (Kg)] - 1530. The volume ratio (%)
[(volume from reconstructed image /predicted volume) x 100] of alcoholic patients
was 135.9+/-25.8, which was significantly higher than that of chronic hepatitis B
(73.6+/-15.4) and chronic hepatitis C (74.5+/-20.7). Patients with chronic viral
hepatitis were classified into Child-Pugh class A (N=10), B (N=14) and C (N=11).
Analysis of variance and trend test revealed that the volume ratio had a
significant decreasing trend from the control group (100.5+/-8.1), class A
(83.4+/-13.9), class B (72.2+/-13.2) to class C (63.3+/-14.4). CONCLUSIONS: Liver
volume can be predicted from patients' weight and height if they have no liver
disease. The liver volume ratio correlates much better with etiology and severity
of the disease and is a reliable predictor for patient's survival.
PMID- 9756009
TI - Recovery of liver functions following surgical biliary decompression in
obstructive jaundice.
AB - BACKGROUND/AIMS: Derangement of liver functions in obstructive jaundice has been
known to influence surgical outcome. The pattern and time frame of liver function
recovery in patients with surgical obstructive jaundice undergoing a bilioenteric
anastomosis has not been comprehensively defined in human beings. METHODOLOGY:
Fifty patients of obstructive jaundice who underwent a bilioenteric anastomosis
had their liver function evaluated done by biochemistry (pre-operatively and
postoperatively on day 1,4,7 and 6 weeks) and radionuclide mebrofenin scan
(preoperatively and 6 weeks postoperative). RESULTS: The results have shown a
constant and significant decline in serum bilirubin levels by day 4 (p=0.04),
however the decline in serum levels was not uniformly progressive in 54%
patients. The decline in serum alkaline phosphatase levels has been constant and
progressive reaching significant levels by day 4(p=0.01). Serum transaminases
showed an initial rise followed by a rapid fall, again achieving significant
levels by day 4 (p=0.003 & 0.009). Serum albumin decreased on day 1 itself but
remained static after that. On isotope scanning hepatic uptake showed uniform
improvement with 92% of patients having achieved a normal uptake after 6 weeks.
Gastrointestinal excretion of the isotope however was still delayed in 26%
patients at 6 weeks. Almost all these patients had an abnormal bilirubin level
decline in the immediate postoperative period. CONCLUSIONS: Hepatic functional
recovery has been seen to start immediately following bilioenteric anastomosis
and has usually completed itself by 6 weeks. Patients who show an abnormal
recovery pattern based on bilirubin levels need to be observed for a longer time.
PMID- 9756010
TI - Zinc metabolism after transcatheter arterial embolization for hepatocellular
carcinoma.
AB - BACKGROUND/AIMS: Zinc metabolism after transcatheter arterial embolization (TAE)
was studied in 15 cases of hepatocellular carcinoma (HCC) with liver cirrhosis
(LC). METHODOLOGY: Serum zinc concentrations, 24-hr urinary excretion of zinc,
blood ammonia (NH3) and plasma endotoxin (Et) levels were measured before and
one, three and seven days after TAE. RESULTS: Serum zinc levels one day after TAE
were decreased (p<0.05) as compared to those before TAE and then returned to
pretreatment values three days or more after TAE. Urinary excretion of zinc
increased (p<0.01) one day after TAE, but then returned to the pretreatment value
three days after TAE. Although blood NH3 and plasma Et levels increased (P<0.05)
the day after TAE, these parameters recovered on the third day. CONCLUSIONS:
Decrease in the serum zinc concentration after TAE is considered to be due to
changes in the zinc distribution in the body associated with endotoxemia, as well
as increased urinary zinc excretion.
PMID- 9756011
TI - Imaging of large early and early advanced hepatocellular carcinomas of more than
5 cm in diameter: report of two cases.
AB - In an attempt to clarify the imaging characteristics of large early and early
advanced hepatocellular carcinoma (HCC), we present two such cases which were
greater than 5 cm in diameter. One case had four early HCCs and the other had
early advanced HCC which was followed for five years and nine months. Multiphasic
CT, CT arteriography (CTA), CT arterial portography (CTAP), and MR imaging were
performed. Early HCC was shown as a low density mass by multiphasic contrast CT,
CTAP and as a hyperintense mass on a T1-weighted image (WI) and isointense on
T2WI. Early advanced HCC was demonstrated as a hypodense mass with hyperenhancing
interior nodules on CTA, and isodense with hypodense internal foci on CTAP. One
follow-up case showed a multi-step progression from early to early advanced HCC,
and finally to overtly advanced HCC. Despite the unusually large size of these
two tumors, the findings of multiphasic CT, CTA, CTAP, and MR imaging were
consistent with those seen in common-sized (less than 2 cm) early and early
advanced HCCs. Multi-step progression of hepatocarcinogenesis was observed in one
case.
PMID- 9756012
TI - Asymptomatic glucagonoma presenting with an isolated hepatic nodule.
AB - A 37-year-old male patient, without any particular symptoms apart from moderate
right upper quadrant postprandial pain, was found to have a liver mass identified
as a glucagon-producing tumor. Plasma glucagon levels were slightly increased,
whereas those of other gut peptides were within the normal range. Despite an
extensive pre- and intraoperative diagnostic work-up, a presumed primary
glucagonoma remained undetected. This unusual presentation with the absence of
any symptoms typical of glucagonoma, as well as the presence of histopathological
features characteristic of both benign and malignant forms of glucagonoma, make
this case very peculiar. A clinically silent, apparently unrelated adenocarcinoma
of the left colon was also found. The concomitant presence of a glucagonoma and a
carcinoma of the large intestine has not been previously reported, and its
significance remains unclear.
PMID- 9756013
TI - Needle track seeding following percutaneous ethanol injection for treatment of
hepatocellular carcinoma.
AB - We report two cases of needle track seeding in the subcutaneous tissue and
intercostal muscles following percutaneous ethanol injection for the treatment of
hepatocellular carcinoma. In one patient, tumor seeding was observed 11 months
after a total of 12 alcohol injections, and in the other patient, tumor seeding
was observed 30 months after a total of 18 alcohol injections. The cases reported
in the literature are discussed.
PMID- 9756014
TI - Hypoplasia of the left hepatic lobe associated with floating gallbladder: a case
report.
AB - Agenesis or hypoplasia of the hepatic lobe and floating gallbladder are both
rare. We report an extremely rare case of hypoplasia of the left hepatic lobe
accompanied by floating gallbladder. The patient was a 71-year-old woman, with no
past history of related symptoms, who was admitted for further evaluation of
postprandial epigastralgia, nausea, and diarrhea. Laboratory data on admission
showed chronic liver disease with positive anti-hepatitis C virus antibody.
Abdominal ultrasonography and computed tomography revealed the absence of the
left hepatic lobe and displacement of the gallbladder to the left. On endoscopic
retrograde cholangiography, the cystic duct originated from the right side of the
bile duct, but the gallbladder was displaced to the left. Poor yolk-induced
gallbladder contraction suggested the existence of hypotonic biliary dyskinesia.
Angiography demonstrated no middle or left hepatic arteries, indicating
congenital hypoplasia of the left hepatic lobe. Open cholecystectomy was carried
out, and a diagnosis of hypoplasia of the left hepatic lobe accompanied by
floating gallbladder and chronic hepatitis was confirmed. We believe that this is
the first reported case of a hypoplasia of the left hepatic lobe coexisting with
floating gallbladder.
PMID- 9756015
TI - Metastasis and invasion of hepatocellular carcinoma mimicking a right adrenal
tumor.
AB - A 60-year-old man presented with a large right adrenal mass. Adrenal primary
carcinoma invading the liver and retrohepatic inferior vena cava was suspected
after preoperative imagings, which included ultrasonography, computed tomography,
selective hepatic and adrenal angiography, and magnetic resonance imaging. An en
bloc resection of the right kidney, right adrenal gland, posterior hepatic
segment, and laterodorsal of the vena cava was performed using an active veno
venous bypass. The defect of the inferior vena cava was closed using a 6 x 10 cm
patch of horse pericardium. The cut surface of the resected specimens revealed a
smaller necrotic intrahepatic tumor as well as a large extrahepatic tumor which
involved the right adrenal gland and extended continuously to the liver,
mimicking an adrenal tumor. As the histological features of the two tumors
disclosed the same moderately differentiated hepatocellular carcinoma with a
trabecular or pseudoglandular pattern, a huge mass of the right adrenal gland
with invasion into the right lobe of the liver, which mimicked a primary adrenal
tumor, was diagnosed as metastatic hepatocellular carcinoma from a primary
hepatic tumor.
PMID- 9756016
TI - Comparison of different endocrine stimulation tests in nondiabetic patients with
chronic pancreatitis.
AB - BACKGROUND/AIMS: The purpose of this study was to evaluate endocrine functional
impairment in nondiabetic patients with chronic pancreatitis and to determine its
reliability in the staging of this disease. METHODOLOGY: Eighteen patients with
chronic pancreatitis and fasting normoglycemia (fasting blood glucose level < 100
mg/dl) and 10 healthy subjects underwent an oral glucose tolerance test (OGTT),
an intravenous glucose test (IGT) and an arginine stimulation test (AST). Blood
glucose and serum concentrations of insulin, C-peptide and glucagon were measured
before and after stimulation. Exocrine pancreatic function was assessed by the
pancreolauryl serum test (PLT), and morphological changes were staged by
endoscopic retrograde pancreaticography (ERP), which were rated as I (mild), II
(moderate) or III (severe). RESULTS: Glucagon and C-peptide secretions after
arginine stimulation were reduced in patients with moderate and severe chronic
pancreatitis while no parameter was able to show impaired endocrine function in
the early stage (ERP I) of the disease. Serum insulin concentrations proved to be
of no use in the diagnosis of pathological B-cell function, since even patients
with severe chronic pancreatitis and fasting normoglycemia demonstrated normal
insulin secretion. CONCLUSIONS: We conclude that there is a close correlation
between morphological changes of the pancreas and functional endocrine reserve
capacity, whereas endocrine stimulation tests were not shown to be helpful in the
clinical assessment of nondiabetic patients with chronic pancreatitis.
PMID- 9756017
TI - Duodenum-preserving resection of the pancreatic head for mucinous ductal ectasia
without overt carcinoma.
AB - BACKGROUND/AIMS: The clinical characteristics of mucinous ductal ectasia (MDE) of
the pancreas without overt carcinoma have not been clarified. To clarify MDE and
assess the optimal treatment procedure, including the technique of duodenum
preserving resection of the pancreatic head (DpRPH), we studied four patients.
METHODOLOGY: Our patients consisted of three men and one woman, with a mean age
of 71 years. The patients underwent DpRPH (n=3) or the pylorus-preserving Whipple
procedure (PpW) (n=1). Clinicopathological features, postoperative pancreatic
function, and technique to preserve duodenal blood flow were studied. RESULTS:
All patients had intraductal mucin-hypersecretion and multilocular cysts lined by
hyperplastic epithelium. The lesions were located in the uncinate process (n=3)
or head-body (n=1) of the pancreas. DpRPH totally removed the lesions in the
uncinate process. Of the three patients receiving DpRPH, dusky duodenum and a
postoperative duodenal ulcer developed in two whose gastroduodenal arteries (GDA)
were divided, but did not develop in one with undivided GDA. Postoperative
glucose tolerance test and peptide para-aminobenzoic acid test after DpRPH showed
better values than those after PpW. All patients are alive and well 22 to 40
months after surgery. CONCLUSIONS: DpRPH is a new standard for MDE. During DpRPH,
preservation of the GDA and the superior portion of the pancreatic head is
recommended to maintain an adequate duodenal blood flow.
PMID- 9756018
TI - Regional versus systemic chemotherapy for advanced pancreatic cancer: a
randomized study.
AB - BACKGROUND/AIMS: In an attempt to improve treatment protocols for advanced
pancreatic cancer, the value of regional chemotherapy compared with systemic
chemotherapy was investigated in this randomized study. METHODOLOGY: Fourteen
patients with advanced non-resectable pancreatic adenocarcinoma were randomized
receiving either systemic chemotherapy with mitomycin, mitoxanthrone and
cisplatin (5pts.) or celiac axis infusion regional chemotherapy with SpherexR
microembolization. In the systemic group one patient was stage III, four patients
were stage IV, in the intraarterial group two patients were specified stage III
and seven were stage IV. RESULTS: In the systemic group one stable disease and
four progressive diseases were noted, in the regional group two stable diseases
and seven partial responses were noted. Median survival was 11 weeks in the
systemically treated patients versus 33 weeks in the patients treated with
intraarterial infusion (p=0.001). One patient became resectable (R0).
CONCLUSIONS: Performance status improved during regional chemotherapy whilst it
steadily decreased in the patients treated systemically. The study was terminated
at that point.
PMID- 9756019
TI - AgNORs in duct epithelial lesions in chronic pancreatitis and in pancreas cancer
cells.
AB - BACKGROUND/AIMS: Argyrophilic nucleolar organizer regions (AgNORs) reflect the
proliferative activity of cells. Since the majority of pancreatic cancers are
ductal carcinomas, the aim of the study was to determine the AgNORs expression of
potential pre-neoplastic ductal epithelial lesions in advanced chronic
pancreatitis compared with pancreatic cancer cells. METHODOLOGY: Histological
preparations obtained from 24 patients with chronic pancreatitis and 16 patients
with pancreatic cancer were used to estimate the number of AgNORs per nucleus.
Four types of AgNORs were distinguished and histograms with cell percentage of
each type were performed for all forms of epithelial anomalies. RESULTS: In
simple hyperplasia, squamous and mucous metaplasia the number of AgNORs ranged
from 1.92 to 2.23; type I was predominant. In papillary hyperplasia, dysplasia
and in situ carcinoma the number ranged from 2.98 to 3.34, with a predominance of
type II-IV. In invasive carcinoma the number was 4.29 and 74% of cells were of
type II-IV. CONCLUSIONS: Both counts of AgNORs and the percentage of type II-IV
cells showed a gradual increase from simple hyperplasia through papillary
hyperplasia and dysplasia to invasive carcinoma which in this respect differs
significantly from all forms of the epithelial anomalies examined.
PMID- 9756020
TI - End to side mucomucosal Wirsung jejunostomy after pancreaticoduodenectomy:
immediate results and long term follow-up.
AB - BACKGROUND/AIMS: Pancreatico-duodenectomy (PD) is nowadays a widely performed
operation which still carries a risk of some morbidity and mortality due to
leakage of the Pancreatico-jejunostomy. The aim of the present paper is to
describe critically the experience of a surgical team with a large number of
consecutive non-selective PDs, where the same surgical procedure was adopted in
all cases to manage the pancreatic stump. METHODOLOGY: Sixty six Whipple/Child
PDs and 4 Traverso-Longmire (Duodenum Preserving PD) were performed between 1974
and 1993, by the same surgical team in our surgical department. The management of
the pancreatic stump was always the same: a hand-made end-to-side mucomucosal
Wirsung-jejunostomy, completed by a second layer between pancreatic capsula and
jejunal sero-muscular wall. RESULTS: The overall mortality was 7.1% (5 cases).
Only one death could be ascribed to pancreatico-jejunostomy related complications
(post-operative acute pancreatitis). Specific morbidity was 12.6% (9 cases). Only
one complication was related to the Wirsung-jejunostomy (leakage of the
anastomosis, treated by a "sleeve" end-to-end pancreato-jejunostomy). Long-term
patency of the anastomosis was shown by ERCP. CONCLUSIONS: Even if this
anastomotic technique requires a little more time and attention by the surgeon,
we think that the low incidence of pancreatico-jejunal anastomosis related
complications represents a validation of the method, and a motivation to adopt
this anastomotic technique. The long-term patency of the muco-mucosal Wirsung
jejunostomy is another valid argument that supports this kind of management of
the pancreatic stump after PD.
PMID- 9756021
TI - Pancreatic trauma in patients with pancreatobiliary anomaly.
AB - One patient with a choledochal cyst and anomalous pancreaticobiliary junction had
pancreatic transection causing bile peritonitis. Intraoperative
cholangiopancreatography revealed this anomaly. In another patient with pancreas
divisum, cannulation of the minor papilla (ERCP) demonstrated focal stenosis of
the dorsal pancreatic duct, corresponding to the site of the minor laceration.
The possibility of a coexisting pancreatobiliary anomaly should be considered in
the diagnosis of pancreatic trauma, particularly in terms of the interpretation
of pancreatograms.
PMID- 9756022
TI - Advanced small cell pancreatic cancer: relevance of laparoscopic staging.
AB - Small cell pancreatic cancer is a rare pancreatic malignancy. Thus, it offers
substantial therapeutic perspectives. As demonstrated in this case, surgical
laparoscopy might not only be used for staging in resectable pancreatic cancers
but also in advanced cases for adequate tissue sampling and rapid diagnosis.
PMID- 9756023
TI - Idiopathic hyperamylasemia.
AB - A 25-year-old pregnant Japanese woman was diagnosed with idiopathic
hyperamylasemia. The administration of a beta-stimulant caused a further increase
in the serum levels of pancreas-type amylase and lipase.The patient's
hyperamylasemia concomitant with elevated serum levels of lipase, elastase 1, and
trypsin lasted over a 4 year-period, in which the patient remained asymptomatic.
It is possible that the pancreas in some women with the idiopathic
hyperamylasemia can respond to a beta-adrenoceptor stimulation with respect to
pancreatic enzyme secretion.
PMID- 9756024
TI - Management of the pancreatic metastases from renal cell carcinoma: report of four
resected cases.
AB - The pancreas is an uncommon site for metastasis from renal cell carcinoma. In
most cases, pancreatic metastases occur as part of widespread nodal and visceral
involvement, and there is thus evidence of metastatic disease elsewhere in the
body. We present 4 cases with resectable pancreatic metastases arising from renal
cell tumors without involvement of the regional lymph nodes at the operation.
Three cases out of 4 were asymptomatic and the pancreatic metastases were
detected by routine follow-up examination of renal cell carcinoma. Aggressive
surgical treatment for the solitary metastatic lesion is advocated. Spread of
renal cell carcinoma to the pancreas is, however, via the hematogenous route, and
even solitary pancreatic metastasis may be one of the manifestations of the
systemic metastasis of renal cell carcinoma. No pancreatic regional lymph nodes
metastases were noted. Pancreatectomy should be undertaken to remove the tumor
with adequate resection margins while preserving as much of the gland as
possible. The prognosis of pancreatic metastases arising from a renal cell
carcinoma is discussed with a review of the literature. Adjuvant chemo- and
endocrine therapy should also be considered in these cases.
PMID- 9756025
TI - Injection sclerotherapy for gastric varices using N-butyl-2-cyanoacrylate and
ethanolamine oleate.
AB - BACKGROUND/AIMS: Tissue adhesive agents, such as the cyanoacrylates, have been
used as an alternative to conventional sclerotherapy to treat gastric varices,
but the long-term efficacy of this approach has not been determined. We evaluated
the efficacy and long-term outcome of injection sclerotherapy with n-butyl-2
cyanoacrylate and ethanolamine oleate in 16 patients with gastric varices.
METHODOLOGY: We evaluated the effect of injection sclerotherapy in 16 Japanese
patients with gastric varices. Injection sclerotherapy was performed on an
emergency basis in 6 patients, an elective basis in 5 patients, and as
prophylaxis in 5 patients. RESULTS: No bleeding was observed in the 7 patients in
whom gastric varices disappeared during the 51 month follow-up period. The non
bleeding rate after treatment was significantly higher in this group than in the
9 patients in whom gastric varices did not disappear (p<0.05). Acute bleeding was
stopped in 5 (83.3%) of 6 patients. The single failure was a patient in whom the
sclerosant could not be injected into the gastric varices. No serious
complications, such as emboli in other organs, were observed. CONCLUSION: The
results suggest that this therapy is a safe and useful treatment for gastric
varices and that the goal of injection sclerotherapy should be the disappearance
of gastric varices.
PMID- 9756027
TI - Gastric emptying and antral myoelectrical activity in chronic alcoholics with
dyspepsia.
AB - BACKGROUND/AIMS: Chronic alcoholism is known to effect gastric motor activity. An
association between gastric motility disorders and abnormal myoelectrical
activity has been observed in various gastrointestinal and extra-intestinal
diseases. The aim of this study was to investigate the effect of chronic
alcoholism on gastric emptying and antral myoelectrical activity. METHODOLOGY:
Electrogastrography (EGG) was performed on 20 chronic alcoholics with chronic
dyspepsia using a pair of electrodes sonographically placed on the skin overlying
the gastric antrum. After an overnight fast, patients were tested over a period
of one hour in the a) fasting and b) fed state, after ingestion of a 370 kcal
liquid-solid test meal. The following EGG parameters were determined: dominant
frequency (DF (cpm); DF (%) in the normal range (2-4 cpm); bradygastria (<2 cpm);
tachygastria (4-10 cpm); dominant frequency instability coefficient (DFIC), and
postprandial to fasting power ratio (PR). The data were correlated with results
obtained from 20 controls matched for age and sex. In 18 alcoholics, the EGG data
were compared to the percentage of radionuclides (liquid phase labeled with 99m
Tc colloid) remaining in the stomach after 60 minutes (%) (gamma camera system).
Moreover, for the alcoholics, various parameters such as ethanol consumption, and
gastrointestinal symptoms were determined and related to EGG values and
scintigraphy. RESULTS: About 50% of the alcoholics showed delayed gastric
emptying compared to normal values previously reported (t 60 values: >68%). In
opposite to scintigraphy, the alcoholics did not exhibit abnormalities in antral
myoelectrical activity. They had significantly decreased bradygastria measures
compared to controls (p<0.05). The scintigraphic t 60 values did not correlate
either with EGG values or with dyspepsia and clinical parameters. EGG values did
not correlate with dyspepsia. However, increased preprandial DF was significantly
correlated with ethanol consumption. CONCLUSIONS: Chronic alcoholism induces a
disturbance of gastric emptying, probably resulting from toxic damage of the
gastrointestinal smooth muscles. Disturbances in antral myoelectrical activity
were not found.
PMID- 9756026
TI - Significant risk factors of recurrence in muscularis proprial carcinoma of the
stomach.
AB - BACKGROUND/AIMS: The aim of this study is to elucidate significant risk factors
of recurrence in muscularis proprial gastric cancer (MPGC). METHODOLOGY: Seventy
three patients who underwent curative gastrectomy for MPGC were divided into 14
patients with postoperative recurrence (Group 1) and 59 patients without
recurrence (Group 2). A retrospective study of Group 1 compared the
clinicopathological features with Group 2. RESULTS: There were no significant
differences of age, gender and operative method including frequency of lymph node
dissection between Group 1 and Group 2. Although tumor size, gastric location and
histological type did not significantly differ between the two groups, the rate
of Borrman type in Group 1 (71.4%) was significantly higher than in Group 2
(42.4%). Significant risk factors of recurrence in pathological findings were the
presence of secondary lymph node metastasis or more, lymphatic and venous
involvement. Median survival in Group 1 (28.8 months) was significantly worse
than in Group 2 (59.0 months). The 1-year, 3-year, and 5-year survival rates
between Group 1 versus Group 2 were 71.4% versus 98.3% (p<0.01), 28.6% versus
96.7% (p<0.01), and 7. 1% versus 95.0 (p<0.01), respectively. CONCLUSIONS:
Prognosis of the postoperative recurrence in MPGC was very poor. More careful
prophylactic treatment against recurrence of MPGC should therefore, be prescribed
in patients with the aforementioned risk factors of recurrence.
PMID- 9756028
TI - Gastric re-resection in emergency.
AB - BACKGROUND/AIMS: We reviewed a consecutive series of patients with acute
complications following gastric resection, in order to evaluate the role of
gastric re-resection as the operation of choice in emergency. METHODOLOGY:
Records of 90 patients with acute complications following gastric resection
observed from January 1991 to January 1996 were retrospectively analyzed.
RESULTS: Hemorrhagic events occurred in the vast majority of cases (87), either
as acute complications after a long time since surgery (78 cases) or as early
postoperative complications (9). Among late acute complications, three cases were
related to bleeding cancer of the gastric stump. Anastomotic obstructions
presenting as acute complications occurred in 3 cases. Emergency surgery was
indicated in three cases of acute obstruction, in 1 case of bleeding cancer of
the gastric stump, in 9 (12%) out of the 75 remaining late acute hemorrhagic
complications and in 1 (11%) out of 9 early hemorrhagic complications. Completion
gastrectomy was chosen in the one case of bleeding cancer of the gastric stump
with indication for emergency surgery. Gastric re-resection was performed in 11
cases: 9 for hemorrhagic complications and 2 for obstructive acute complications.
In two cases, one for hemorrhage and one for occlusion, other surgical procedures
were carried out. CONCLUSIONS: Gastric re-resection can represent the most
suitable operation in acute complications following gastric resection.
PMID- 9756029
TI - The relationship between stapling doughnuts: characteristics and functional
results after total gastrectomy.
AB - BACKGROUND/AIMS: The objective of this study was to determine whether the
thickness of the esophageal doughnut is related to postoperative results in total
gastrectomy. METHODOLOGY: Thirty-eight total gastrectomy patients were studied,
including 18 who underwent jejunal pouch reconstruction and 20 who did not have
pouch reconstruction. We used the Proximate-ILS circular stapler, with purse
string suturing at the cut end of the esophagus performing only the mucosal layer
manually in all cases. We divided the esophageal doughnuts after stapling into
two groups: Group A: doughnut involving muscle tissue of 0-25% of the esophageal
circumference; Group B: doughnut involved muscle tissue of 25-100% of the
esophageal circumference. Reflux scores and the scintigraphic reflux index were
determined. RESULTS: No significant difference was found between the two groups
in reflux score or scintigraphic reflux index. CONCLUSIONS: These findings
indicate that the degree of postoperative reflux esophagitis was not affected by
the amount of the muscular layer included in the esophageal doughnut. Continuity,
and not variability of the degree of involved muscle in the esophageal doughnut,
is an important factor at the time of stapling.
PMID- 9756030
TI - Gastric cancer with metastases to the distant peritoneum: a 20-year surgical
experience.
AB - BACKGROUND/AIMS: The efficacy of palliative gastrectomy in gastric cancer with
peritoneal metastases remains uncertain. The aim of the present study was to
evaluate the benefits of gastrectomy on the postoperative course of patients with
gastric cancer and simultaneous metastases to the distant peritoneum.
METHODOLOGY: A total of 122 patients who had gastric cancer and metastases to the
distant peritoneum were studied with respect to survival. RESULTS: The extent of
peritoneal metastases did not significantly affect the prognosis. Moreover,
multivariate analysis indicated that surgery without gastrectomy was the only
significant prognostic factor (relative risk, 2.587). CONCLUSIONS: Our results
suggest that the decision to perform gastrectomy does not depend on the extent of
peritoneal metastasis in gastric cancer. Furthermore, palliative gastrectomy, if
feasible, seems to have a beneficial effect on the postoperative course and is
indicated for patients regardless of metastasis to the peritoneum, if the primary
tumor is surgically resectable and there is no evidence of liver metastasis.
PMID- 9756031
TI - Modulation of volitional ethanol intake in the rat by central delta-opioid
receptors.
AB - The acute effect of opioid antagonists on volitional ethanol intake was studied
in unselected Sprague-Dawley rats using a two-bottle, free-choice model. The
total daily intake of ethanol during saline treatment was 1.79 +/- 0.4 g/kg/day
(n = 136). The rats were deprived of fluids for the last 4 hr of the light
period. Saline or drug was given intraperitoneally 20 to 30 min before the onset
of dark, and the ethanol and water intakes were measured during the following
hour. The ethanol intake during this hour was 0.75 +/- 0.06 g/kg (n = 136).
Naltrexone significantly reduced ethanol intake. There was also a significant
reduction in ethanol intake following administration of ICI-174,864. Naloxonazine
and naloxone methiodide lacked effect. None of the treatments had any effect on
the water or food intake. The results suggest that central delta-opioid receptors
modulate volitional ethanol intake in the rat.
PMID- 9756032
TI - Effects of nicotine and mecamylamine microinjections into the nucleus accumbens
on ethanol and sucrose self-administration.
AB - Nicotine (NIC) and ethanol (ETOH) are both drugs of abuse that can affect similar
pathways in the central nervous system. However, the role of nicotinic processes
in ETOH's reinforcing actions is unclear. Although the mesolimbic dopamine
systems are known to be involved in the reinforcing effects of ETOH, the role of
nicotinic receptors within the nucleus accumbens (NAc) in ETOH reinforcement has
not been studied. To address this issue, adult male Long-Evans rats were
initiated to self-administer ETOH (10% v/v, n = 14) using the sucrose
substitution procedure or sucrose (5% w/v, n = 8) in a 30-min operant session.
They were then surgically implanted with bilateral stainless-steel guide cannulae
to allow for microinjection into the core of the NAc. After recovery from
surgery, presession microinjections of NIC (0.3, 3.3, 10, 30, and 60 microg/1
microl/brain) or the antagonist mecamylamine (MEC) (1, 3, 10, 30, and 60 microg/1
microl/brain) were performed prior to an ETOH or sucrose self-administration
session. NIC (3.3 and 60 microg/microl) and MEC (30 microg/microl) both reduced
ETOH self-administration behavior, without affecting sucrose-reinforced behavior.
A reduction in the total duration of ETOH responding (termination) was also
observed after either 60 microg/microl of NIC and 30 microg/microl of MEC. The
lack of a clear dose-response relationship for the agonist and the antagonist
indicates that the interaction between the NAc nicotinic system and ETOH self
administration is complex.
PMID- 9756034
TI - Chronic ethanol treatment leads to increased ornithine decarboxylase activity:
implications for a role of polyamines in ethanol dependence and withdrawal.
AB - Recent research has focused on the N-methyl-D-aspartate receptor system as a
major site of ethanol action in the brain and specifically on compensatory
changes in the expression of the polyamine-sensitive NR2B subunit. Therefore, we
examined the effects of chronic ethanol treatment on polyamine homeostasis in the
rat brain. Wistar rats were made dependent by ethanol vapor inhalation. This
caused a rise in hippocampal ornithine decarboxylase (ODC) activity that was
correlated with the appearance of physiological dependence. ODC activity returned
to control levels within 3 days of ethanol withdrawal. Enzyme activity also
increased in the cerebral cortex, striatum, and cerebellum of the ethanol
dependent rats. The concentration of the polyamines (putrescine, spermidine, and
spermine) in the hippocampus was increased in ethanol-dependent rats. Injection
of the ODC inhibitor, alpha-difluoromethylornithine (500 mg/kg) at the onset of
withdrawal resulted in a significant reduction in the severity of withdrawal
behaviors. The level of ODC activity and the severity of withdrawal behaviors
were positively correlated. Perturbed polyamine homeostasis may represent an
important molecular component in the initiation of ethanol withdrawal behaviors
in the ethanol-dependent rat.
PMID- 9756033
TI - Reversal of ethanol-induced testosterone suppression in peripubertal male rats by
opiate blockade.
AB - Teenage drinking is a major problem in the United States, as well as abroad.
Besides psychosocial implications, ethanol (EtOH) has detrimental effects on the
reproductive system. Clinical problems associated with reduced reproductive
hormones include osteoporosis, decreased muscle function, anemia, altered immune
function, prostate involution, and decreased reproductive abilities. Education
coupled with strategies aimed at preventing these deleterious consequences even
in the face of continued EtOH intake is extremely important. We have tested the
possibility that naltrexone, a drug currently used in patients to decrease
alcohol craving, might also prevent the fall in the male hormone, testosterone,
caused by EtOH exposure. Rats aged 35 days old (prepubertal), 45 days old
(midpubertal), and 55 days old (late pubertal) were injected (intraperitoneally)
with either saline, EtOH, naltrexone, or EtOH plus naltrexone. In the two older
age groups, EtOH significantly suppressed testosterone, which was prevented by
administration of naltrexone. In the youngest animals, there was no treatment
effect presumably due to low basal levels of testosterone. EtOH similarly reduced
luteinizing hormone (LH), but this suppression was not prevented by naltrexone.
There was no consistent effect of any treatment on hypothalamic concentration of
pro-LH releasing hormone (RH) (LHRH), LHRH, or on steady-state levels of LHRH
mRNA. We conclude that, as animals progress through puberty, EtOH suppresses LH
and testosterone. The testosterone decline can be prevented by opiate blockade
with naltrexone, an effect primarily seen at gonadal level. Thus, naltrexone, a
drug already used clinically to reduce EtOH intake, also has protective
physiological effects on the endocrine system.
PMID- 9756036
TI - Long-term ethanol consumption selectively impairs ganglioside pathway in rat
brain.
AB - Gangliosides are sialo-glycosphingolipids that play important roles in the
interaction of cells with their environment and are thus involved in the
regulation of many cellular events. Sialic acid residues are important for the
conformation of a glycomolecule, their structural stability and their functions.
Although decreased brain ganglioside sialic acid has been previously reported as
a result of chronic ethanol treatment in rats, no reports are available on the
sialylation of specific gangliosides and/or the mechanism leading to depletion of
their sialic acid residues. Therefore, in this investigation, we have examined
the effects of chronic ethanol treatment on (1) incorporation of [4,5-3H]N
acetylmannosamine (ManNAc) into specific rat brain gangliosides, GD3, GD1a, GT1a,
and GT1b; and (2) enzymatic activities of brain sialyltransferase and sialidase
at specific subcellular levels. The experiments were done in male Wistar rats
pair-fed with either ethanol or control liquid diets for a period of 8 weeks. The
rats were intracerebroventricularly injected with labeled ManNAc (30 microCi/rat)
and killed after 90 min. Radioactivity was determined in respective ganglioside
bands separated on a thin layer chromatography system. Specific activities of
sialyltransferase and sialidase were assessed using GM3 and GD3 as substrates,
respectively. The results showed significant decreases of 57.7% (p < 0.001) and
68.9% (p < 0.001), respectively, in the labeled ManNAc incorporation into GD3 and
GD1a fractions in rats of the ethanol group, compared with rats of the control
group. No significant changes were noted in the incorporation of labeled ManNAc
into GT1a or GT1b ganglioside fractions between the ethanol and control groups.
Concomitantly, compared with control rats, a decrease of 18.9% (p < 0.05), 20.6%
(p < 0.05), and 15.8% (p < 0.001) was found in the sialyltransferase activity,
respectively, at the whole brain, and brain Golgi and synaptosomal levels.
However, dramatic increases of 32.4% (p < 0.05), 105% (p < 0.001), and 150% (p <
0.001) in sialidase activity were found, respectively, at the whole brain and
brain cytosol and synaptosomal fractions of rat treated chronically with ethanol.
Thus, we conclude that the deleterious actions of ethanol on the sialylation of
rat brain gangliosides is specific, and the reduced sialic acid label found in
GD3 and GD1a in this study is mainly due to increased activity of brain
sialidase. Furthermore, the study reaffirms our tenet that, regardless of whether
it is the liver or the brain, glycosylation cascade is one of the main target of
the deleterious attacks of ethanol.
PMID- 9756035
TI - Identification of the human P-450 enzymes responsible for the sulfoxidation and
thiono-oxidation of diethyldithiocarbamate methyl ester: role of P-450 enzymes in
disulfiram bioactivation.
AB - Diethyldithiocarbamate methyl ester (DDTC-Me) is a precursorto the formation of S
methyl-N,N-diethylthiolcarbamate sulfoxide, the active metabolite proposed to be
responsible for the alcohol deterrent effects of disulfiram. The present study
investigated the role of human cytochrome P-450 (CYP) enzymes in sulfoxidation
and thiono-oxidation of DDTC-Me, intermediary steps in the activation of
disulfiram. Several approaches were used in an attempt to delineate the
particular P-450 enzyme(s) involved in the sulfoxidation and thiono-oxidation of
DDTC-Me. These approaches included the use of cDNA-expressed human P-450 enzymes,
correlation analysis with sample-to-sample variation in human P-450 enzymes in a
bank of human liver microsomes, and chemical and antibody inhibition studies.
Multiple human P-450 enzymes (CYP3A4, CYP1A2, CYP2A6, and CYP2D6) catalyzed the
sulfoxidation of DDTC-Me, as determined with cDNA-expressed enzymes. Several
lines of evidence suggest that the sulfoxidation of DDTC-Me by human liver
microsomes is primarily catalyzed by CYP3A4/5, including (1) a high correlation
between DDTC-Me sulfoxidation and testosterone 6beta-hydroxylation; (2) increased
DDTC-Me sulfoxidation in the presence of alpha-naphthoflavone, an activator of
CYP3A enzymes; (3) inhibition of this reaction by inhibitors of CYP3A4/5 enzymes,
such as troleandomycin and ketoconazole; and (4) inhibition of DDTC-Me
sulfoxidation by antibodies against CYP3A enzymes. On the other hand, several
lines of evidence suggested that the thiono-oxidation of DDTC-Me by human liver
microsomes is catalyzed in part by CYP1A2, CYP2B6, CYP2E1, and CYP3A4/5,
including (1) these human P450 enzymes among others have the capacity to catalyze
this reaction, as determined with cDNA-expressed enzymes; (2) a high correlation
between DDTC-Me thiono-oxidation and testosterone 6beta-hydroxylation, weak
inhibition by ketoconazole, troleandomycin, and anti-CYP3A antibodies suggested a
minor role for CYP3A4; (3) a high correlation with immunoreactive CYP2B6
suggested involvement of this enzyme; (4) weak inhibition of DDTC-Me thiono
oxidation by furafylline and anti-CYP1A antibody suggested involvement of CYP1A2;
and (5) inhibition of DDTC-Me thiono-oxidation by DDTC and anti-CYP2E antibodies
suggested a role for CYP2E1. Collectively, these data suggested CYP3A4/5 enzymes
are the major contributors to the sulfoxidation of DDTC-Me by human liver
microsomes, and CYP1A2, CYP2B6, CYP2E1, and CYP3A4/5 contribute toward DDTC-Me
thiono-oxidation by human liver microsomes. This study, in conjunction with
others (Madan et al., Drug Metab. Dispos. 23:1153-1162, 1995), may help explain
the variability in disulfiram's effectiveness as an alcohol deterrent.
PMID- 9756037
TI - A characterization of approach and avoidance learning in alcohol-preferring and
alcohol-nonpreferring rats.
AB - Although numerous biochemical and physiological differences have been shown to be
correlated with alcohol preference, less is known about behavioral factors that
may correlate with alcohol preference. Using a signaled barpressing task, alcohol
preferring (P; n = 18) and alcohol-nonpreferring (NP; n = 19) rats were compared
for their ability to learn an appetitive and an aversive task. Results showed
that P rats had difficulty learning the tasks in comparison with NP and
nonselected, control rats when appetitive training was given first. However, if
aversive training came first, the NP rats performed poorly in comparison with the
P and nonselected rats. These results suggest that these lines of rats may differ
in behavioral inhibition and sensitivity to conditioned fear. Furthermore, these
behavioral differences may offer a richer analysis of the traits that were co
selected with the alcohol-seeking and alcohol-avoiding phenotypes.
PMID- 9756038
TI - Ethanol-induced conditioned taste aversion in BXD recombinant inbred mice.
AB - Genetic differences in sensitivity to ethanol's aversive effects may play an
important role in the development of alcohol-seeking behavior and alcoholism. The
present study examined the development of ethanol-induced conditioned taste
aversion in 20 BXD/Ty recombinant inbred strains of mice and their progenitor
inbred strains, C57BL/6J (B6) and DBA/2J (D2). Adult male mice were given 1-hr
access to a saccharin-flavored solution every 48 hr for 12 days. After all but
the first and last saccharin access periods, they received ethanol injections (0,
2, or 4 g/kg, i.p.). Separate groups of unpaired control mice received 4 g/kg of
ethanol 1 hr after water access. Saline control mice were also used for examining
preference across a wide range of saccharin concentrations (0.019 to 4.864% w/v).
As expected, saccharin consumption during taste conditioning declined over
conditioning trials in a dose-dependent manner, indicating development of ethanol
induced conditioned taste aversion. Correlational analyses using strain means
from recently published papers indicated no significant genetic correlation
between taste conditioning and two phenotypes thought to reflect ethanol
reinforcement or reward (ethanol drinking, conditioned place preference).
However, there were significant genetic correlations between taste conditioning
at the high dose and sensitivity to ethanol-induced hypothermia, rotarod ataxia,
and acute withdrawal. Quantitative trait locus (QTL) analyses of strain means
indicated that taste aversion was associated (p < 0.01) with genetic markers on
nine chromosomes (1, 2, 3, 4, 6, 7, 9, 11, and 17). These QTLs were located near
several candidate genes, including genes encoding several different acetylcholine
receptor subunits, the delta opioid receptor, and two serotonin receptors (1B and
1D). QTLs for saccharin preference were located on several of the same
chromosomes (2, 3, 4, 6, and 11). Two of these saccharin QTLs overlap candidate
genes influencing sensitivity to sweet or bitter taste stimuli. In general, these
findings support the conclusion that multiple genes influence ethanol-induced
conditioned taste aversion. Some of these genes appear to influence taste
sensitivity, whereas others appear to mediate sensitivity to aversive
pharmacological effects of ethanol.
PMID- 9756039
TI - The effects of chronic ethanol consumption on the formation of
phosphatidylethanolamine molecular species and their appearance at the plasma
membrane.
AB - The purpose of our study was to determine whether chronic ethanol consumption
affected membrane assembly by altering the formation of specific molecular
species of phosphatidylethanolamine (PE) and their subsequent incorporation into
the plasma membrane (PM). We investigated the effects on the PE species made by
the two major pathways in hepatocytes: (1) from CDP-ethanolamine in the
endoplasmic reticulum, and (2) by the decarboxylation of phosphatidylserine (PS)
in the mitochondria. Ethanol consumption exerted significant effects on the
formation of ethanolamine-derived PE species and affected mainly two species, the
16:0/22:6 and 18:0/20:4 species. In cultured hepatocytes from ethanol-fed rats
labeled with [3H]ethanolamine for 0.25 to 4 hr, the amount of the [3H]16:0/22:6
PE species was decreased compared with that in control cells, whereas the amount
of [3H]18:0/20:4 species was increased. The amount of the [3H]16:0/22:6 PE
species on the cell surface was also decreased in hepatocytes from ethanol-fed
rats, whereas the amount of [3H]18:0/20:4 species was increased. In contrast, the
profile of [3H]PE species formed in cells treated with [3H]serine exhibited minor
alterations, and the profile of the serine-derived [3H]PE species on the cells
surface was not altered after 4 hr of labeling. The changes in ethanolamine
derived species were apparently caused by time-dependent alterations in the
metabolic processes, because the presence of 110 mM ethanol in the culture media
did not affect the profiles of [3H]PE species in cells from control or ethanol
fed rats and was not required to sustain the altered profiles. The results
indicate that the synthesis of specific PE molecular species and their appearance
on the PM may occur by compartmentalized processes which are distinguishable by
different sensitivities to ethanol consumption. The results indicate that ethanol
consumption may contribute alcoholic hepatic injury by interfering with the
metabolism of specific PE molecular species and their assembly into the PM.
PMID- 9756040
TI - Effect of prenatal ethanol exposure on the developmental profile of the NMDA
receptor subunits in rat forebrain and hippocampus.
AB - The effects of prenatal ethanol exposure on the NMDAR1 protein expression
(postnatal days 1 and 7) and on the developmental profile of the NMDAR2A and
NMDAR2B subunits in rat forebrain and hippocampus were investigated. Forebrain
and hippocampal membrane proteins were isolated from pups of various ages
(postnatal days 1 to 21) from prenatally ethanol exposed, pair-fed and ad libitum
control groups. A semiquantitative immunoblot procedure was used with antibodies
raised against the NMDAR1, NMDAR2A, and the NMDAR2B subunits to assess the NMDA
subunit protein expression in the samples. NMDAR1 protein expression was
unaffected by prenatal ethanol exposure at postnatal day 1 or 7 in both the
forebrain and hippocampus. NMDAR2A protein expression levels rose rapidly in both
forebrain and hippocampus during the time frame of study. Prenatal ethanol
exposure caused a significant reduction in protein expression levels of the
NMDAR2A in forebrain through postnatal day 14. NMDAR2B protein expression levels
were high throughout the study in both forebrain and hippocampus. Prenatal
ethanol exposure significantly reduced protein expression of the NMDAR2B in the
forebrain (through postnatal day 14) and hippocampus (up to day 7). The results
suggest that there may be a link between the depressed expression of the NMDAR2
subunits and the neurodevelopmental disorders associated with fetal ethanol
exposure.
PMID- 9756042
TI - Development of rapid tolerance to ethanol-stimulated serotonin release in the
ventral hippocampus.
AB - This study was designed to examine the effects of acute intraperitoneal (i.p.)
ethanol injection on the extracellular levels of serotonin (5-HT) in the ventral
hippocampus (vHIP) and to determine whether a single prior exposure to ethanol
could alter the response to a second dose of ethanol given 24 hr later. In the
first experiment, in vivo microdialysis coupled with high pressure liquid
chromatography-electrochemical detection (HPLC-EC) was used to assess the effects
of 1.0, 1.75, and 2.5 g/kg ethanol on vHIP 5-HT extracellular levels in ethanol
naive adult male Wistar rats. The largest dose significantly increased the
extracellular concentration of 5-HT (p < 0.001) to a maximum of approximately
180% of baseline values within 50 min; thereafter, the levels of 5-HT began to
return toward baseline. The 1.75 g/kg dose also transiently increased 5-HT levels
above baseline; however, no significant increase was observed with 1.0 g/kg
ethanol. The results of the second experiment demonstrated that the i.p. dose of
2.5 g/kg ethanol had no significant effect on the extracellular levels of 5-HT if
rats had been given a single i.p. 2.5 g/kg dose of ethanol 24 hr earlier. Because
the vHIP receives a major 5HT input from the median raphe nucleus (MRN), the
results suggest that acute ethanol activates the MRN 5-HT system projecting to
the vHIP and that rapid tolerance develops to the activating effects of alcohol
on this pathway.
PMID- 9756041
TI - Effect of ethanol drinking on the gene expression of opioid receptors,
enkephalinase, and angiotensin-converting enzyme in two inbred mice strains.
AB - There is convincing evidence that genetic factors contribute to the
predisposition to alcoholism. In this respect, alcohol-preferring (like C57BL/6
mice) and alcohol-avoiding lines (like DBA/2 mice) of animals served as models in
the search for neurobiological substrates of excessive ethanol consumption. One
of the systems that is thought to be associated with the incidence of alcoholism
is the endogenous opioid system. In the first experiment, basal mRNA levels of mu
and delta-opioid receptors, and of opioid-degrading enzymes enkephalinase
(neutral endopeptidase 24.11; NEP) and angiotensin-converting enzyme (ACE) in the
brain regions of C57BL/6 and DBA/2 mice did not reveal genetically determined
differences in these parameters between the two strains. Furthermore, in the
brain regions studied, the corresponding enzyme activities of NEP and ACE did not
differ significantly between the lines of mice, except for a higher NEP activity
in the striatum and olfactory bulb of DBA/2 mice (p < 0.01). In the second
experiment, C57BL/6 and DBA/2 mice were offered a free choice between water and
10% ethanol solution for 4 weeks and were killed thereafter; from another group,
ethanol was removed for 3 days and from a third group ethanol was removed for 3
weeks before killing. In the striatum, a highly significant increase in the ACE
mRNA amount was detected after 3 weeks of removal of ethanol in C57BL/6 mice,
whereas in DBA/2 mice the delta-opioid receptor mRNA level was increased at this
time when compared with the corresponding ethanol treatment group. The most
striking changes were seen in the hypothalamus, where mu-opioid receptor, ACE,
and NEP mRNA amounts markedly decreased after ethanol treatment in both strains.
Thus, chronic ethanol intake caused significant changes in the gene expression of
distinct components of the endogenous opioid system. These findings further
underline an involvement of the opioid system in the effects of ethanol.
PMID- 9756043
TI - Early events in the development of neuronal polarity in vitro are altered by
ethanol.
AB - Among the neuropathological effects of prenatal exposure to ethanol is the
disruption of neuromorphogenesis. The effects of ethanol on early events in the
development of axons and dendrites were studied using cultured embryonic rat
hippocampal neurons, which develop in vitro in a stereotypical sequence of events
that mimics their development in vivo. During the first 24 hr in culture,
hippocampal neurons attach to the substrate and develop into one of three stages
identified by phase-contrast microscopy: (i) neurons having lamellipodia and no
processes (stage 1); (ii) neurons developing minor processes (<40 microm) that
subsequently become the cell's axon or dendrites (stage 2); or (iii) polarized
neurons with at least one axon (process with length > or =40 microm) (stage 3).
Exposure to ethanol (300 mg/dl or 800 mg/dl) in the culture medium resulted in an
increase in both the number of minor processes per neuron and the number of stage
3 neurons having more than the typical single axon. In addition, ethanol exposure
significantly altered the proportion of neurons in the three early stages of
development at 18 to 24 hr in vitro, without affecting overall neuron survival.
With ethanol, there was a smaller proportion of neurons in the first stage of
development, and a greater proportion of polarized stage 3 neurons. These
findings suggest that ethanol alters the normal establishment of neuronal
polarity, disrupting mechanisms that ensure the formation of the appropriate
number of processes and that regulate the timing of process outgrowth.
PMID- 9756044
TI - Ethanol counteraction of clonidine-evoked inhibition of norepinephrine release in
rostral ventrolateral medulla of rats.
AB - Previous studies from our laboratory demonstrated an antagonistic hemodynamic
interaction between ethanol and clonidine in conscious and in urethane
anesthetized rats. The present study tested the hypothesis that ethanol produces
its effect by counteracting clonidine-evoked inhibition of norepinephrine (NE)
release at its major site of action, the rostral ventrolateral medulla (RVLM). In
vivo electrochemical measurement of real-time changes in NE level in the RVLM of
urethane-anesthetized Sprague-Dawley rats was made along with blood pressure and
heart rate. Clonidine (30 microg/kg, i.v.) produced significant decreases (p <
0.05) in NE electrochemical signal and blood pressure. Ethanol (1 g/kg, i.v.)
administered 10 min after clonidine significantly (p < 0.05) increased NE signal
and counteracted clonidine-evoked hypotension. Equal volume of saline had no
effect on NE signal in the RVLM nor on the hypotensive response to clonidine.
Pretreatment with the same dose of ethanol (1 g/kg) caused slight increases in
RVLM NE level and in blood pressure, but did not influence the electrochemical
and blood pressure responses to clonidine; clonidine (30 microg/kg)
administration 10 min after ethanol resulted in significant (p < 0.05) decreases
in NE signal and blood pressure. These findings suggest that: (i) ethanol
counteraction of the hypotensive action of clonidine involves, at least in part,
opposite effects on central pathways that use NE as a neurotransmitter; (ii) the
RVLM represents a possible site for the adverse hemodynamic interaction between
ethanol and clonidine; and (iii) ethanol-evoked increase in RVLM NE, which
correlates with its pressor effect, is much enhanced when RVLM NE level is
reduced by clonidine.
PMID- 9756045
TI - Acute effects of ethanol on recombinant kainate receptors: lack of role of
protein phosphorylation.
AB - This study examined the acute actions of ethanol on recombinant rat GluR6 kainate
receptors expressed in Xenopus oocytes and HEK 293 cells. Electrophysiological
recordings showed that co-application of ethanol with submaximal kainate
concentrations resulted in similar inhibition of kainate-gated currents in both
expression systems. Manipulation of intracellular phosphorylation pathways by
intracellular dialysis with a solution without ATP and GTP did not modify the
inhibitory effects of ethanol. Moreover, co-transfection of GluR6 receptor
subunits with PKA-alpha catalytic subunit or the calcium/calmodulin-dependent
protein kinase II (CamKII) catalytic fragment did not change the sensitivity of
the receptor to ethanol. Treatment of Xenopus oocytes with specific inhibitors of
PKC, PKA, CamKII, tyrosine kinases, and serine-threonine protein phosphatases did
not affect the 100 mM ethanol-induced inhibition of GluR6 receptor-mediated
currents. Biochemical experiments with transiently transfected HEK 293 cells
confirmed published reports that GluR6 receptors are minimally phosphorylated
under basal conditions in these cells and also revealed that acute ethanol did
not increase GluR6 phosphorylation. These results suggest that, under our
experimental conditions, ethanol inhibits recombinant GluR6 receptor function by
a direct effect on the receptor rather than an indirect action via protein
phosphorylation.
PMID- 9756046
TI - Matching alcoholism treatments to client heterogeneity: Project MATCH three-year
drinking outcomes.
AB - This study reports 3-year outcomes for clients who had been treated in the five
outpatient sites of Project MATCH, a multisite clinical trial designed to test a
priori client treatment matching hypotheses. The main purpose of this study was
to characterize the status of the matching hypotheses at the 3-year follow-up.
This entailed investigating which matching findings were sustained or even
strengthened across the 3-year study period, and whether any hypotheses that were
not supported earlier eventually emerged at 3 years, or conversely, whether
matching findings discerned earlier dissipated at this later time. This research
also examines the prognostic effects of the client matching attributes,
characterizes the overall outcomes at 37 to 39 months, and explores differential
effects of the three treatments at extended follow-up. With regard to the
matching effects, client anger demonstrated the most consistent interaction in
the trial, with significant matching effects evident at both the 1-year and 3
year follow-ups. As predicted, clients high in anger fared better in Motivational
Enhancement Therapy (MET) than in the other two MATCH treatments: Cognitive
Behavioral Therapy (CBT) and Twelve-Step Facilitation (TSF). Among subjects in
the highest third of the anger variable, clients treated in MET had on average
76.4% abstinent days, whereas their counterparts in the other two treatments (CBT
and TSF) had on average 66% abstinent days. Conversely, clients low in anger
performed better after treatment in CBT and TSF than in MET. Significant matching
effects for the support for drinking variable emerged in the 3-year outcome
analysis, such that clients whose social networks were more supportive of
drinking derived greater benefit from TSF treatment than from MET. Among subjects
in the highest third of the support for drinking variable, TSF participants were
abstinent 16.1% more days than MET participants. At the lower end of this
variable, difference in percent days abstinent between MET and TSF was 3%, with
MET clients having more abstinent days. A significant matching effect for
psychiatric severity that appeared in the first year posttreatment was not
observed after 3 years. Of the 21 client attributes used in testing the matching
hypotheses, 11 had prognostic value at 3 years. Among these, readiness-to-change
and self-efficacy emerged as the strongest predictors of long-term drinking
outcome. With regard to the overall outcomes, the reductions in drinking that
were observed in the first year after treatment were sustained over the 3-year
follow-up period: almost 30% of the subjects were totally abstinent in months 37
to 39, whereas those who did report drinking nevertheless remained abstinent an
average of two-thirds of the time. As in the 1-year follow-up, there were few
differences among the three treatments, although TSF continued to show a possible
slight advantage.
PMID- 9756047
TI - Bone age and growth in fetal alcohol syndrome.
AB - We have found delayed mean bone age in 63 children with fetal alcohol syndrome
(FAS). The mean bone age Z-score for boys (n = 31) was -2.12 SDs and for girls (n
= 32) was -1.62 SDs. This might suggest that they have potential for catch-up
growth. However, experience with children with intrauterine growth retardation
suggests that this will not be the case and that FAS children will be of reduced
height at maturity. Further support for this assumption was gained from a sample
of 26 patients who were followed until at least the age of 14 years for females
and 16 years for males. There was no significant change in height Z-scores from
early childhood to early adulthood, the mean score being -2.16 SDs and -2.11 SDs
at mean ages of 4.83 years and 18.69 years, respectively. On the other hand,
there were significant changes in weight and head circumference. The mean weight
Z-score changed from -2.10 SDs to -1.14 SDs (p < 0.001). The head circumference
mean Z-score in 16 patients was -3.13 SDs at a mean age of 2.79 years and -2.63
SDs at a mean age of 17.37 years (p = 0.013). Short stature can continue to be
used as a diagnostic criterion for FAS beyond childhood.
PMID- 9756049
TI - Hyperhyaluronanemia in alcoholic hepatitis is associated with increased levels of
circulating soluble intercellular adhesion molecule-1.
AB - The purpose of this study was to evaluate the role of the sinusoidal endothelial
cell (SEC) during the clinical course of alcoholic hepatitis. Twenty consenting
patients (mean age: 49.4 +/- 11.0 years) with moderate or severe hepatitis were
studied. The patients were selected and characterized according to their history
of drinking and laboratory profile, including serum aminotransferases, bilirubin,
total white blood cell and neutrophil count, and prothrombin times. C-reactive
protein and interleukin-6 were also measured as markers of the hepatic acute
phase response. A marker of the SEC functional state, the circulating level of
hyaluronan, was measured in parallel with the circulating levels of soluble
intercellular adhesion molecule (sICAM)-1 over a 6-month observation period. All
patients were hospitalized for the first month and encouraged to abstain from
drinking for the duration of the study. The initial increased levels of both
hyaluronan (542 +/- 32 ng x ml(-1) serum) and sICAM-1 (488 +/- 70 ng x ml(-1)
serum), gradually fell during the 6-month observation period, eventually reaching
values close to those seen in healthy subjects. A positive correlation was
obtained between changes in these two markers of SEC function/activation on the
one hand, and between these two tests and bilirubin, on the other hand. These
data indicate that abnormalities of SEC function/activation, as reflected by
serum hyaluronan and siCAM-1, are prominent in alcoholic hepatitis, and these
alterations improve within relatively short periods of time after cessation of
alcohol consumption.
PMID- 9756048
TI - Amplitude of visual P3 event-related potential as a phenotypic marker for a
predisposition to alcoholism: preliminary results from the COGA Project.
Collaborative Study on the Genetics of Alcoholism.
AB - Recent data collected at six identical electrophysiological laboratories from the
large national multisite Collaborative Study on the Genetics of Alcoholism
provide evidence for considering the P3 amplitude of the event-related potential
as a phenotypic marker for the risk of alcoholism. The distribution of P3
amplitude to target stimuli at the Pz electrode in individuals 16 years of age
and over from 163 randomly ascertained control families (n = 687) was compared
with those from 219 densely affected alcoholic families (n = 1276) in which three
directly interviewed first-degree relatives met both DSM-III-R and Feighner
criteria at the definite level for alcohol dependence (stage II). The control
sample did not exclude individuals with psychiatric illness or alcoholism to
obtain incidence rates of psychiatric disorders similar to those of the general
population. P3 amplitude data from control families was converted to Z-scores,
and a P3 amplitude beyond 2 SD's below the mean was considered an "abnormal
trait." When age- and sex-matched distributions of P3 amplitude were compared,
members of densely affected stage II families were more likely to manifest low P3
amplitudes (2 SD below the mean) than members of control families, comparing
affected and unaffected offspring, and all individuals; all comparisons of these
distributions between groups were significant (p < 0.00001). P3 amplitude means
were also significantly lower in stage II family members, compared with control
family members for all comparisons, namely probands, affected and unaffected
individuals (p < 0.0001), and offspring (p < 0.01). Furthermore, affected
individuals from stage II families, but not control families, had significantly
lower P3 amplitudes than unaffected individuals (p < 0.001). Affected males from
stage II families had significantly lower P3 amplitudes than affected females (p
< 0.001). Recent linkage analyses indicate that visual P3 amplitude provides a
biological phenotypic marker that has genetic underpinnings.
PMID- 9756050
TI - Compliance with treatment and follow-up protocols in project MATCH: predictors
and relationship to outcome.
AB - Treatment and follow-up session attendance data from Project MATCH, a multisite
clinical trial investigating patient-treatment matching, were analyzed to study
compliance. High rates of compliance to both therapy and research protocols were
achieved, enhancing treatment integrity and data quality. Strong baseline
predictors of compliance did not emerge, and the small relationships found were
consistent with reports from previous studies. Attendance at therapy sessions was
moderately correlated with research follow-up participation. Treatment compliance
predicted drinking outcome, underscoring the importance of retaining patients in
treatment. Future studies should examine the associations between compliance and
structural features of the treatment environment, treatment delivery, and context
features that are often under the control of the clinician/investigator.
PMID- 9756051
TI - Overt behavior problems and serotonergic function in middle childhood among male
and female offspring of alcoholic fathers.
AB - A large body of literature indicates that the serotonergic system is involved in
behavioral regulation, as evidenced by the inverse relationship between impulsive
aggression and serotonergic function found in adult alcoholics and nonalcoholics.
However, studies of this relationship among child and adolescent offspring of
alcoholics (COAs) have not previously been done. This study examines the
potentially parallel relationship between behavioral dysregulation and low
serotonergic function in young COAs. The relationship is of potential interest as
a phenotypic marker of biological vulnerability to aggressiveness, which itself
has been hypothesized to be a risk factor for later antisocial alcoholism. The
present work is part of an ongoing prospective study of the development of risk
for alcohol abuse/dependence and other problematic outcomes in a sample of
families subtyped by the fathers' alcoholism classification. We examined the
relationship between overt behavior problems in middle childhood (mean age = 10.5
+/- 1.7 years) and whole blood serotonin (5-HT) in a subsample of the offspring
(N = 32 boys and 12 girls). Using a Child Behavior Checklist (CBCL) index of
behavioral undercontrol, we obtained results indicating that high total behavior
problem (TBP) children had lower levels of whole blood 5-HT than did low-TBP
children (p < 0.01). These results support the hypothesis that there is an
inverse relationship between whole blood serotonin levels and behavior problems
in young male and female COAs. A father's alcoholism status was not significantly
related to his child's 5-HT level, i.e., the child's phenotypic expression of
behavioral dysregulation was more reliably connected to serotonergic function
than was paternal alcoholism.
PMID- 9756052
TI - Predicting the development of late-life late-onset drinking problems: a 7-year
prospective study.
AB - There has been little empirical study of risk factors for the development of late
life late-onset drinking problems. In the current prospective study, we compare
two groups of older adults who, at a baseline assessment, were nonproblem
drinkers: individuals who developed drinking problems over the course of the next
7 years (n = 77) and those who did not (n = 197). Late-onset problem drinkers
reported mild to moderate drinking problems and spontaneous remission rates were
high. Compared with stable nonproblem drinkers, late-onset problem drinkers at
baseline were more likely to report incipient problems, heavier alcohol
consumption, greater friend approval of drinking, more reliance on avoidance
coping strategies, were more likely to smoke, and were less likely to have acute
medical conditions that could potentially be complicated by alcohol consumption.
Contrary to expectation, life stressors did not predict drinking problem onset.
However, compared with stable nonproblem drinkers, late-onset problem drinkers
were more likely to have a history of responding to stressors and negative affect
with increased alcohol consumption.
PMID- 9756053
TI - Association of alcohol or other drug dependence with alleles of the mu opioid
receptor gene (OPRM1).
AB - Opioidergic neurotransmission and, specifically, the mu opioid receptor have been
implicated in the reinforcing effects of a variety of drugs of abuse.
Consequently, the present study examined the association of a polymorphic (CA)n
repeat at the OPRM1 locus (the gene coding for the mu opioid receptor) to alcohol
or drug dependence in 320 Caucasian and 108 African-American substance-dependent
or control subjects. Among Caucasians, suggestion of a modest association, which
could be interpreted as statistically significant (p = 0.03), was observed
between OPRM1 alleles and substance (alcohol, cocaine, or opioid) dependence.
Analysis by specific substance showed only a trend level association to alcohol
dependence. Comparisons among African Americans yielded no evidence for
association. Further studies of the association between alleles of the OPRM1 gene
and substance dependence appear warranted, particularly if they use a family
based approach to control for population stratification. Phenotypes other than a
broad diagnostic categorization, such as opioid antagonist effects on drinking
behavior in alcoholics, may provide more consistent evidence of a role for OPRM1
in behavioral variability.
PMID- 9756054
TI - Mismatch negativity in young children of alcoholics from high-density families.
AB - The mismatch negativity (MMN) component of event-related potentials was recorded
from a group of young children of alcoholics (n = 19, 8 females) with a high
density family history of alcoholism and from a control group (n = 23, 12
females), between 8 and 15 years of age. A dichotic listening task was used, and
subjects had to pay attention to an oddball paradigm in one ear and ignore the
stimuli in the other ear. The event-related potentials elicited by the standard
unattended tones were subtracted from those elicited by the infrequent deviant
unattended tones, and the MMN was measured at 10 frontal and central electrodes.
No group differences were observed in peak latency, peak amplitude, and mean
amplitude of the MMN. These results indicated that preattentive mechanisms of
mismatch detection were not impaired in young subjects at high risk for
alcoholism. Results are discussed in relation to differences in
electrophysiological indexes of automatic versus controlled information
processing and in relation to the characteristics of the sample.
PMID- 9756055
TI - Effect of recent alcohol intake on parathyroid hormone and mineral metabolism in
men.
AB - The mechanisms by which alcohol intake, particularly moderate alcohol intake,
effects bone metabolism are poorly defined. We have examined the relationship
between mineral metabolism and recent self-reported alcohol intake (SRAI) across
a wide range of such intakes in a series of 104 men aged 32 to 78 years of age in
an outpatient setting. A morning nonfasting urine, serum specimen and recent SRAI
were obtained from each subject. SRAI was reported as between 0 and 45 oz/week.
SRAI correlated positively with liver function tests, including serum bilirubin
(r = 0.30, p = 0.002), alkaline phosphatase (r = 0.30, p = 0.004), and aspartate
aminotransferase (SGOT) (r = 0.29, p = 0.006). SRAI correlated with serum calcium
corrected for albumin (r = -0.39, p < 0.001), estradiol (r = 0.43, p < 0.001),
and immunoreactive parathyroid hormone (iPTH) (r = -0.51, p < 0.001), as well as
urinary calcium (per 100 mg of creatinine) (r = 0.55, p < 0.001). We have
arbitrarily divided the participants into two groups on the basis of their
reported alcohol intake. Individuals in the first group had intakes ranging from
none to moderate intake (drank 8.4 oz or less of ethanol per week, equivalent to
an average of two drinks daily or less). Those in the second group had moderate
or heavier intake, with >8.4 oz of ethanol intake/week. Mean serum iPTH was
significantly greater in those in the first group (none to moderate), compared
with the second group (moderate or heavier) (56.0 +/- 3.4 and 39.9 +/- 2.0
pM/liter, respectively). Calcium corrected for serum albumin was significantly
greater in individuals in the first, compared with the second, group (9.23 +/-
0.05 vs. 8.88 +/- 0.07 mg/dl, respectively). In addition, urinary calcium
(corrected per 100 mg of creatinine) was significantly lower in the former,
compared with the latter (3.1 +/- 0.4 vs. 8.4 +/- 1.1 mg/100 mg of creatinine,
respectively). Similarly, urinary excretion of collagen crosslinks (corrected per
100 mg of creatinine) was significantly less in men in the second group, compared
with the first group (316 +/- 38 vs. 530 +/- 78 nM/100 mg of creatinine,
respectively). Not surprisingly, a series of correlations between iPTH and age,
250-hydroxyvitamin D, and testosterone were significant in individuals with none
to moderate SRAI, but not moderate or heavier SRAI. Significant independent
predictors of serum iPTH in the entire group of men were age (beta = 0.215, p =
0.025), SRAI (beta = -0.281, p = 0.003), 250-hydroxyvitamin D (beta = -0.309, p =
0.002), and testosterone (beta = -184, p = 0.048). We have concluded that, in
free-living men, alcohol intake >8.4 oz/week was associated with decreased serum
iPTH concentrations.
PMID- 9756056
TI - What makes alcohol-dependent individuals early in abstinence crave for alcohol:
exposure to the drink, images of drinking, or remembrance of drinks past?
AB - Craving is a major factor in addiction, predicting poorer outcome to treatment To
improve our understanding of craving for alcohol, we have compared in the
laboratory the effects of inducing craving for alcohol by exposure to the sight
and the smell of an alcoholic beverage, imagery of craving scripts, and recall of
autobiographical memories of craving. We used subjective measures of craving,
together with autonomic measures, in 14 abstinent alcohol-dependent individuals
in the first month after detoxification. All subjects reported a significant
increase in ratings of urges after exposure to alcoholic drinks, following the
imagery of craving and after recalling autobiographical memories of craving.
Physiological measures have shown that craving imagery as well as memory
induction were equally effective as exposure to alcoholic drinks in modestly
increasing autonomic arousal (indicated by systolic blood pressure). Our
preliminary findings support the existing evidence in nicotine and opiate
dependence that images and memories are as effective as in vivo exposure in
eliciting craving for drugs.
PMID- 9756057
TI - Diagnosis and treatment of postoperative chyle leakage via percutaneous
transabdominal catheterization of the cisterna chyli: a preliminary study.
AB - PURPOSE: To assess the feasibility of percutaneous transabdominal puncture and
catheterization of the cisterna chyli or lymphatic ducts (PTCLD) in patients with
postoperative chyloperitoneum and chylothorax, and to identify and possibly
embolize the chylous fistula. MATERIALS AND METHODS: Five patients had
postoperative uncontrolled chyle fistulas. Two patients with chylothorax had
thoracic duct (TD) ligation after esophagectomy and neck surgery. The other three
patients had chylous ascites after surgery of the pancreas, the aorta, and the
esophagus, respectively. After lymphographic opacification, the cisterna chyli
(CC) or retroperitoneal lymph ducts were punctured transabdominally with a 21
gauge needle and catheterized with a 3-F catheter to reach the TD if possible.
Microcoils were used to embolize a TD laceration. RESULTS: Lymph ducts as small
as 2-3 mm were catheterized successfully in three patients. The TD was
catheterized in two patients; one TD fistula was embolized with cure of
chylothorax. In one patient with a surgically tied TD, duct occlusion was
confirmed despite continued pleural effusion. Three fistulas, not seen with
lymphography, were identified in two of three chylous ascites and one
chylothorax. There was no morbidity. As a result of this procedure, four of five
patients did not require repeated operation. CONCLUSIONS: PTCLD in the study of
chyle fistulas was feasible and safe in the management of five patients and
clinically useful in four patients; transabdominal catheter lymphography with
aqueous contrast medium is more sensitive than pedal lymphography. Further
evaluation is necessary.
PMID- 9756059
TI - Successful treatment of renal transplant ureter stenosis with use of the biliary
Z stent.
PMID- 9756058
TI - Real-time CT-fluoroscopy for guidance of percutaneous drainage procedures.
PMID- 9756060
TI - Percutaneous transvesical drainage of a seminal vesicle abscess.
PMID- 9756061
TI - Percutaneous embolotherapy of lower gastrointestinal hemorrhage.
AB - PURPOSE: To evaluate percutaneous embolotherapy in the treatment of lower
gastrointestinal hemorrhage. MATERIALS AND METHODS: Twenty-one patients who
underwent attempted percutaneous embolization for acute lower gastrointestinal
bleeding between 1982 and 1997 were retrospectively studied. Hemorrhagic sites
included jejunum (n = 4), ileum (n = 4), cecum (n = 4), and the remaining colon
(n = 9). RESULTS: Embolization was not technically possible in four patients
(19%). Hemostasis was achieved in 15 patients (71%) with prolonged hemostasis in
10 (48%). All embolizations distal to the cecum resulted in prolonged hemostasis.
Three of four patients with jejunal bleeding had recurrent bleeding after
apparent successful embolization. Only one of four cecal embolizations achieved
prolonged cessation of bleeding. No ischemic complications were identified.
CONCLUSION: Based on these data, it would appear that the risk of bowel
ischemia/infarction in the lower gastrointestinal tract may not be as high as has
been suggested. Two regions (cecum and proximal jejunum) were associated with
poor results, suggesting these areas may not be as responsive to embolotherapy as
other sites in the lower gastrointestinal tract.
PMID- 9756062
TI - Superselective coil embolization in acute gastrointestinal hemorrhage: personal
experience in 10 patients and review of the literature.
AB - PURPOSE: To evaluate the safety and efficiency of microcoil embolization in upper
and lower gastrointestinal hemorrhage. PATIENTS AND METHODS: Superselective
microcoil embolization was performed in 10 patients (upper gastrointestinal
bleeding, n = 3; lower gastrointestinal bleeding, n = 7) who had acute
gastrointestinal hemorrhage. Embolization was performed as peripherally as
possible with use of coaxial catheter systems. Embolization materials included
microcoils (2-4 mm) alone (n = 5), microcoils and polyvinyl alcohol particles
(355-500 microm) (n = 4), and microcoils and gelatin sponge particles (n = 1).
RESULTS: Immediate hemostasis was achieved in eight patients. In two patients
with dual blood supply of the bleeding site, significant reduction of hemorrhage
resulted. In these two patients, it was technically impossible to place the
coaxial catheter distally enough to allow safe embolization of both feeding
vessels. No clinical signs of ischemia or infarction were observed after
intervention. CONCLUSION: Microcoil embolization is a safe and efficient
procedure for controlling acute lower gastrointestinal bleeding if performed in a
superselective catheter position. In upper gastrointestinal bleeding, microcoil
embolization is an established treatment and can be performed more proximally.
PMID- 9756063
TI - Comparison of early deflation rate of detachable latex and silicone balloons and
observations on persistent varicocele.
AB - PURPOSE: To determine the frequency of and time until spontaneous deflation of
detachable embolization balloons made of different materials and the correlation
between persisting or recurrent varicocele and the spontaneous deflation of the
balloons. MATERIALS AND METHODS: Forty-five patients with clinically detected
left-sided varicocele underwent embolization with 78 silicone and 22 latex
balloons. The minimum follow-up time was 3 months and the follow-up consisted of
clinical examination, color duplex ultrasonography, and plain radiography of the
balloons. Those patients who were suspected of having recurrent varicoceles
underwent control venography to assess the internal spermatic vein. RESULTS: All
of the latex balloons and 10% of the silicone balloons deflated spontaneously
during the follow-up. The average time until deflation was 5.1 months for latex
and 9.9 months for silicone balloons. Persistence of varicocele, attributed to
perfusion through a previously occluded portion of the internal spermatic vein,
occurred in two of 11 (18%) recurrences. Nine of 11 (72%) recurrences were due to
bypassing collaterals past the site of detachable balloon placement. CONCLUSIONS:
Latex balloons seem to predispose more to persisting/recurrent varicocele than
silicone balloons. Early deflation of the balloons explained two (18%) of the 11
persisting or recurrent varicoceles. A combination of a sclerosing agent with
balloon embolization of the internal spermatic vein is recommended.
PMID- 9756064
TI - Single institution prospective evaluation of the over-the-wire Greenfield vena
caval filter.
AB - PURPOSE: To assess the technical and clinical success of the over-the-wire (OTW)
Greenfield inferior vena caval (IVC) filter. MATERIALS AND METHODS: Prospective
evaluation of the OTW Greenfield filter in 47 patients was performed during the
course of 18 months. Technical success and deployment problems were documented.
Caval perforation, leg asymmetry, and tilt were evaluated with a postprocedure,
noncontrast computed tomographic (CT) scan. Follow-up was performed at 6- and 12
month intervals after the procedure and included a clinical history, chart
review, and magnetic resonance (MR) imaging examination of the IVC. RESULTS:
Ninety-one percent of filters were placed without technical difficulties and 100%
were successfully deployed. Technical difficulties included sheath kinking prior
to deployment (n = 3), initial incomplete filter opening (n = 1), and wire
entrapment within the filter (n = 1). Of 38 patients evaluated with CT, there was
no case of caval perforation. Twenty-one patients (55%) demonstrated tilt and 14
(37%) had leg asymmetry. Tilting occurred more frequently when the filter was
placed from a femoral approach (51%) than from a jugular approach (12%). Of
patients with leg asymmetry, the vena cava was narrow in anteroposterior (AP)
dimension in five (36%). Of 13 deaths, none were attributed to pulmonary
embolism. One patient (2%) had a recurrent pulmonary embolus. Two of 16 patients
(12%) with MR imaging follow-up had documented IVC thrombosis. CONCLUSIONS: The
OTW Greenfield filter has an effective delivery system, with few difficulties
encountered during deployment. Filter tilt and leg asymmetry are common. The
etiology of leg asymmetry is likely multifactorial but is often associated with a
cava with a small AP diameter. Because OTW deployment appears to offer no benefit
in centering the filter, the authors have elected to remove the wire prior to
filter deployment to avoid possible entanglement. MR imaging follow-up reveals an
acceptable incidence of IVC thrombosis.
PMID- 9756065
TI - Clinical experience with the antecubital Simon nitinol IVC filter.
AB - PURPOSE: To evaluate the Simon nitinol vena cava filter (SNF) placed via the
antecubital vein in a series of patients. Issues examined by the authors included
insertion site variables, filter efficacy, and complications. The authors also
explored the option of placement of a peripherally inserted central catheter
(PICC) via the same access site. MATERIALS AND METHODS: This was a prospective
study that included all patients who had undergone antecubital attempt at
insertion of the SNF. Seventy-four consecutive patients were enrolled during a 29
month period. A PICC was inserted concomitantly in 23 of these patients. The
series included 38 men and 36 women, with a mean age of 62.5 years (range, 17-88
years). The clinical indications for filter placement included contraindication
to anticoagulation (81.1%), complication of anticoagulation (9.4%), failure of
anticoagulation (8.1%), and prophylactic placement (1.4%). Concomitant PICCs were
inserted for chemotherapy (56.5%), venous access (39.1%), and total parenteral
nutrition (4.4%). Clinical follow-up was available in 61 patients. Mean follow-up
was 124 days (range, 0-884 days). RESULTS: The SNF was successfully placed via
the antecubital vein in 98.6% of the patients. In one patient, access was via the
right common femoral vein because of failed right arm access. There was a
question of pulmonary embolism (PE) after filter placement in two patients.
Otherwise, there were no complications related to placement of either the filter
or PICC. CONCLUSION: Antecubital venous insertion of the SNF is a safe and
effective method for the prevention of PE in patients who cannot be managed with
traditional anticoagulation, and offers the option of inserting a PICC with no
added complications.
PMID- 9756066
TI - Autogenous vein-covered stent for the endovascular management of a superior
mesenteric artery pseudoaneurysm.
PMID- 9756067
TI - Blunt traumatic injury to the superior mesenteric artery and celiac axis.
PMID- 9756068
TI - In vitro evaluation of the relative thrombolytic efficiency of forced
intrathrombic injections: saline versus urokinase.
AB - PURPOSE: To compare the rates of thrombolysis produced by forced intrathrombic
injections of saline versus urokinase, as well as automated versus manual
injections of urokinase, with use of an in vitro model of a vascular occlusion.
MATERIALS AND METHODS: The rates of thrombolysis produced by forced intrathrombic
injections of saline and urokinase were compared in an in vitro radiometric model
utilizing I-125-labeled thrombus. Similar experiments were performed to compare
manual and automated injections of urokinase. The dissolution of the thrombus was
quantitatively monitored with use of a scintillation detector. Averaged time
activity data for each type of experiment were fit to exponential functions and
half times of lysis calculated. The differences in the half times for the
experiments being compared were evaluated for significance with use of the
Student t test. RESULTS: The half times of lysis produced by forced intrathrombic
injections of urokinase were substantially and significantly shorter than those
produced by forced saline injections. The half time of lysis produced by
automated injections was not significantly different than that produced by manual
injections. CONCLUSIONS: Forced intrathrombic injections of urokinase produce
faster and substantially more thrombolysis when compared with similarly
administered saline. Also, for forced intrathrombic injections of lytic agents,
an automated injector is an equivalent alternative to manual injections.
PMID- 9756069
TI - New thrombolytic brush catheter in thrombosed polytetrafluoroethylene dialysis
grafts: preclinical animal study.
AB - PURPOSE: To assess the safety, efficacy, endothelial changes, and risks of
pulmonary embolic events after the use of a new thrombolytic brush catheter in
mature thrombosed polytetrafluoroethylene (PTFE) dialysis grafts in an animal
model. MATERIALS AND METHODS: Loop configuration PTFE grafts were implanted in
the femoral vessels of 12 canines 4 weeks before mechanical thrombosis was
performed. The thrombus was allowed to consolidate for 24 hours in 10 animals, 72
hours in one animal, and 7 days in one animal. Standard percutaneous criss-cross
catheter access was performed, and a soft, low-speed, brush (6 mm in diameter),
aided by 250,000 U of periprocedural urokinase, was utilized for thrombolysis.
The native vessels, just distal to the anastomosis, and lungs were evaluated
macro- and microscopically. RESULTS: Thrombolysis was complete in all grafts with
the exception of a small segment between the crossing of the access vascular
sheaths. The total thrombolysis time ranged from 8 to 12 minutes; this included 5
minutes of pulse-spray lacing. No difference in thrombolysis time was found with
regard to the age or amount of thrombus. Minimal endothelial changes were noted
and no evidence of acute pulmonary embolus was found on necropsy or histologic
studies. CONCLUSION: This method offers a simple, safe, and efficient means of
recanalization of thrombosed PTFE dialysis grafts in this canine model.
PMID- 9756070
TI - Phantom for calibration of preoperative imaging modalities in endoluminal stent
graft repair of aortic aneurysms.
AB - PURPOSE: Successful deployment of an endoluminal prosthesis for repair of an
abdominal aortic aneurysm (AAA) is critically dependent on accurate preoperative
assessment of aneurysm morphology with use of such modalities as contrast
aortography (CA), spiral computed tomography (CT), magnetic resonance (MR)
imaging, and intravascular ultrasonography (IVUWS). The authors describe a new
phantom that could be used both to calibrate these four imaging modalities and to
determine which imaging technique(s) is (are) best for preoperative AAA sizing.
MATERIALS AND METHODS: A life-sized AAA model was constructed of silicone
elastomers with luminal access ports for introduction of contrast media and
catheters. Contrast material-filled rings were positioned circumferentially along
the length of the model as reference points for dimension measurements. The
modalities were compared to each other relative to the actual dimensions of the
model, as determined at its construction. RESULTS: In this pilot study, all
modalities were relatively similar in their ability to measure the dimensions of
the AAA model. Length measurements accounted for most of the interinstitutional
and interobserver variability. MR imaging had the least variability. CONCLUSIONS:
The authors developed a new phantom that can be imaged successfully with CA, CT,
MR imaging, and IVUS in repetitive, reproducible fashion. Structural refinements
and future larger scale, statistically significant evaluations of such models
should establish this as a useful adjunct in multicenter endoluminal stent-graft
trials to allow calibration of imaging modalities and to determine which modality
or modalities is (are) best for preoperative AAA sizing.
PMID- 9756071
TI - Effect of iodinated contrast media on neutrophil adhesion to cultured endothelial
cells.
AB - PURPOSE: To investigate the influence of contrast media (CM) on endothelial cells
(ECs) with respect to cytotoxicity and to neutrophil adhesion. MATERIALS AND
METHODS: Human umbilical vein ECs were incubated with chromium-51-labeled human
neutrophils in the presence of CM (diatrizoate, ioxaglate, iopamidol, and
iodixanol) in three concentrations: 2, 20, and 50 mg I/mL. CM was compared with
glucose solutions prepared from plain, buffered glucose solutions, iso-osmolar to
the corresponding CM solution. Neutrophil adhesion to the EC monolayer, EC
morphology, and cytotoxicity were evaluated. RESULTS: The effect of CM on
neutrophil adhesion was dependent on dose, with increased adhesion at low CM
concentrations (2 and 20 mg I/mL) and decreased adhesion at high CM concentration
(50 mg I/mL). The response was observed only if ECs and neutrophils were exposed
to CM simultaneously in a shared environment. Glucose solutions with the same
osmolarity did not show similar effect. Both diatrizoate and ioxaglate had a
greater cytotoxic effect on ECs and neutrophils than did iodixanol and iopamidol.
CONCLUSION: The altered neutrophil adhesion to ECs may be due to CM-induced
cytotoxicity or CM-induced EC activation because the glucose solutions did not
cause a similar change at equal osmolality. The lack of cell death, combined with
altered neutrophil adhesion implies modulation of cell adhesion molecules by CM.
The results could be pertinent to the pathogenesis of peripheral vascular lesions
and the endothelial response in immunosuppressed or septic patients receiving CM
during imaging studies.
PMID- 9756072
TI - Single-specimen bile cytology: a prospective study of 80 patients with
obstructive jaundice.
AB - PURPOSE: To determine the sensitivity, specificity, and charges associated with
single-specimen bile cytologic study in patients with obstructive jaundice.
MATERIALS AND METHODS: Eighty consecutive patients with presumed malignant
biliary strictures underwent percutaneous biliary drainage (PBD). Cytologic
evaluation was performed on a single bile specimen from each patient collected at
the time of the PBD. Final diagnoses were obtained from either percutaneous (n =
14) or surgical (n = 66) histologic specimens (gold standard). Both data sets
were then compared to determine the sensitivity and specificity of bile cytology.
The charges associated with bile cytodiagnosis were compared to those for other
biopsy procedures utilized in the same setting. RESULTS: Eighty bile specimens
were obtained with a mean of 14 mL (range, 3-65 mL) per patient with 79 (99%)
specimens adequate for cytologic processing. Eleven (13%) specimens were
acellular. The overall sensitivity was 15% and specificity was 100%; these values
were not dependent on the volume of the bile specimen (P > .10) or type of
malignancy (P = .10). For bile cytodiagnosis, the mean charge was $160 and the
successful biopsy rate (true-positive plus true-negative results/total number
procedures) was 27%. CONCLUSION: Single-specimen bile cytology has a low
sensitivity; however, because of its convenience, simplicity, atraumatic nature,
and low relative charge versus comparable procedures, it may be useful as an
adjunct to PBD in patients with suspected malignant biliary disease.
PMID- 9756073
TI - Particle embolization for hepatocellular carcinoma.
AB - PURPOSE: To evaluate the outcome of all patients undergoing particle embolization
for hepatocellular carcinoma at a single institution from January 1, 1993,
through December 31, 1995. MATERIALS AND METHODS: The charts and radiographs of
all patients undergoing particle embolization during the study period were
reviewed. The following information was collected: patient demographics, Child
class and Okuda stage, number of embolization treatment sessions, length of
hospital stay, complications related to the embolization procedure, including
postembolization syndrome, current patient status, and date of death. RESULTS:
Forty-six patients underwent 86 embolization sessions during the study period.
Postembolization syndrome developed after 70 of the 86 sessions (81%); in four
cases (4.6%) this required treatment that extended the patient's hospital stay.
Three other complications occurred (3.5%), including a splenic infarct and two
episodes of transient hepatic failure, all treated supportively. There was one
death within 30 days, but it was not directly attributable to embolotherapy.
Follow-up was available for all of the patients who underwent treatment. Thirty
four patients were classified as Child class A, and 12 were classified as Child
class B. Thirty patients were classified as Okuda stage I, 14 were classified as
Okuda stage II, and two were classified as Okuda stage III. Overall actuarial
survival was 50% at 1 year and 33% at 2 years. There was a statistically
significant difference in survival between Okuda stage I and stage II patients,
but not between Child class A and class B patients. CONCLUSION: Particle
embolization for hepatocellular carcinoma is well tolerated and demonstrates
actuarial survival of 50% at 1 year and 33% at 2 years.
PMID- 9756074
TI - Pediatric transvenous liver biopsy.
PMID- 9756075
TI - Thrombosed dialysis grafts: percutaneous mechanical declotting using a central
venous approach.
PMID- 9756076
TI - Puncture-induced deformity of a metallic stent within a dialysis access graft
causing thrombotic failure: case report and description of salvage.
PMID- 9756077
TI - Endovascular interventional MR: balloon angioplasty in a hemodialysis access flow
phantom [corrected].
PMID- 9756078
TI - Stent placement in a carotid artery bypass graft in a patient with Takayasu
arteritis.
PMID- 9756079
TI - Thromboaspiration to treat inadvertent arterial emboli during dialysis graft
declotting.
PMID- 9756080
TI - Percutaneous transthoracic needle biopsy: a difference in definitions and
calculation of diagnostic yield.
PMID- 9756081
TI - Iliofemoral venous thrombolysis after failed surgical thrombectomy.
PMID- 9756082
TI - Wedged hepatic venography with biplane digital subtraction imaging to facilitate
accessing the portal venous system for TIPS.
PMID- 9756083
TI - US-guided puncture of the internal jugular vein: an unexpected anatomic
relationship.
PMID- 9756084
TI - Treatment of malignant ureteric stricture with use of a Vascucoil spring stent.
PMID- 9756085
TI - Extravasation from power injection near previous arteriotomy site: a case for
caution.
PMID- 9756086
TI - Thematic review series II: vasopressin: genes, receptors, water channels, and
antagonists. Introduction.
PMID- 9756087
TI - Vasopressin processing defects in the Brattleboro rat: implications for
hereditary central diabetes insipidus in humans?
AB - The arginine vasopressin (AVP) precursor gene of mammals contains three exons
encoding the principal domains of the polyprotein precursor, including
vasopressin (exon A), neurophysin (exon B), and glycopeptide (exon C). The AVP
precursor (preprohormone) is processed and transported through the endoplasmic
reticulum (ER), Golgi apparatus, and secretory vesicles, and finally, mature AVP
is secreted from the posterior pituitary into the circulation. The exact steps of
these processes during AVP translation and posttranslation events are not yet
well elucidated. Defects in peptide processing are associated with several
genetic disorders, including central diabetes insipidus (CDI). In the Brattleboro
rat with CDI, the mRNA and protein of AVP are present in the hypothalamus, but no
circulating AVP is detectable, thus suggesting a processing defect, transport
defect, or both. The mutated AVP gene precursor of Brattleboro rat has a deletion
of a single base, guanine, in the neurophysin coding region that leads to a
frameshift resulting in the loss of the normal stop codon. It has been reported
that the mutated precursor is trapped in the ER and does not reach the Golgi
apparatus. Recent studies examined AVP secretion in cultured COS cells
transfected with various constructs from wild-type and mutated Brattleboro AVP
gene precursors. The wild-type in vitro studies demonstrated that intact
neurophysin, but not the glycoprotein coding region, is necessary for normal AVP
processing and secretion. Next, the results demonstrated that the guanine defect
in the neurophysin coding region and the prolonged C-terminus accounted for the
processing defect in the Brattleboro rat with CDI. These defects no doubt impair
the folding and configuration necessary for normal processing of the AVP gene
precursor in the ER. In hereditary CDI in humans, the majority of the mutations
have also been shown to occur in the neurophysin coding region. However, in
contrast to the recessive defect in the Brattleboro rat, in human CDI,
neurotoxicity and denigration of the magnocellular neurons have been observed,
and dominant inheritance occurs. Moreover, all mutations are missense, nonsense,
or deletions in human CDI rather than the shift in reading frame and preserved
neurons that is observed with the Brattleboro rat. Thus, the results from studies
in the Brattleboro rat may only be partially applicable to hereditary CDI in
humans.
PMID- 9756088
TI - Vasopressin receptor mutations causing nephrogenic diabetes insipidus.
AB - In congenital nephrogenic diabetes insipidus, the renal collecting ducts are
resistant to the antidiuretic action of arginine vasopressin or to its
antidiuretic analog 1-deamino[8-D-arginine] vasopressin (dDAVP). This is a rare,
but now well described entity secondary to either mutations in the AVPR2 gene
that codes for the vasopressin antidiuretic (V2) receptor or to mutations in the
AQP2 gene that codes for the vasopressin-dependent water channel. A majority (>
90%) of congenital nephrogenic diabetes insipidus patients have AVPR2 mutations:
Of 115 families with congenital nephrogenic diabetes insipidus, 105 families had
AVPR2 mutations, and 10 had AQP2 mutations. When studied in vitro, most AVPR2
mutations lead to receptors that are trapped intracellularly and are unable to
reach the plasma membrane. A minority of the mutant receptors reach the cell
surface but are unable to bind vasopressin or to trigger an intracellular
adenosine 3:5-cyclic phosphate signal properly. Most of the reported mutations
are secondary to a complete loss of function of the receptor, and only a few
mutations have been associated with a mild phenotype. These advances provide
diagnostic tools for physicians caring for these patients because, when the
disease causing mutation has been identified, carrier and perinatal testing could
be done by mutation analysis.
PMID- 9756089
TI - Aquaporin-2 water channel mutations causing nephrogenic diabetes insipidus.
AB - Since the discovery of aquaporin water channels, insight into the molecular
mechanism by which rapid osmotic water occurs across cell membranes has greatly
improved. Aquaporin-2 is the vasopressin-responsive water channel in the
collecting duct, and vasopressin control of water permeability in the collecting
duct occurs in two ways: a short-term regulation and a long-term adaptation. In
congenital nephrogenic diabetes insipidus, the kidney does not respond to
vasopressin. Ninety percent of these patients carry a mutation in the gene coding
for the vasopressin V2 receptor located on the X chromosome. Autosomal recessive
and dominant forms of nephrogenic diabetes insipidus that are caused by mutations
in the aquaporin-2 gene have now been described. This review focuses on recent
insight in the molecular and cellular defect in autosomal nephrogenic diabetes
insipidus.
PMID- 9756090
TI - Disordered water channel expression and distribution in acquired nephrogenic
diabetes insipidus.
AB - A series of recent studies have demonstrated that expression of aquaporin-2
(AQP2), the vasopressin-regulated water channel of the kidney collecting duct, is
greatly reduced in acquired forms of nephrogenic diabetes insipidus (NDI). In
some forms of NDI, there is also impaired delivery of these channels to the
apical plasma membrane, where they permit water reabsorption from the urine. The
combination of these factors is likely to underlie the urinary concentrating
defect that defines these conditions. Direct infusion of vasopressin causes an
increase in AQP2 expression, probably via a rise in cytosolic adenosine 3:5
cyclic phosphate, which also acts as the second messenger, triggering the
delivery of AQP2 to the plasma membrane. However, it is clear from the studies
described that there are also vasopressin-independent pathways that regulate the
expression of AQP2, some of which appear to reflect intranephric changes, whereas
others involve systemic signals. These studies also show that recovery of AQP2
expression, even after correction of the underlying condition, can be slow,
consistent with the clinical observation that recovery of urinary-concentrating
ability often takes weeks or months. An understanding of the cellular signals and
mechanisms responsible for the decrease in AQP2 expression may make it possible
to develop treatments for this common clinical problem.
PMID- 9756091
TI - Vasopressin release, water channels, and vasopressin antagonism in cardiac
failure, cirrhosis, and pregnancy.
AB - Vasopressin (AVP) is released in response to both osmotic and nonosmotic stimuli.
Nonosmotic-stimulated AVP release occurs in cardiac failure, cirrhosis, and
pregnancy in response to alterations in arterial circulatory integrity. Cardiac
failure in rats is associated with increased plasma AVP and hypothalamic AVP
mRNA, and in humans, it is associated with cardiac failure. Plasma AVP
concentrations are elevated when measured with a sensitive radioimmunoassay.
Urinary concentrations of AVP-responsive aquaporin-2 water channels are also
elevated in cardiac failure. V2 receptor antagonists correct the impaired solute
free water excretion seen in rats with low-output cardiac failure and reverse the
upregulation of renal aquaporin-2 water channels. Orally active non-peptide
selective V2 receptor antagonists administered to patients with congestive
cardiac failure decrease urinary concentrations of aquaporin-2, increase solute
free water clearance, and correct the hyponatremia. Cirrhosis of the liver
results in splanchnic arterial vasodilation and increased vascular capacity, most
likely secondary to increased nitric oxide production. This relative underfilling
of the arterial circulation stimulates nonosmotic AVP release with resultant
water retention. Aquaporin-2 gene expression is upregulated in the kidneys of
rats with cirrhosis of the liver. AVP-2 receptor antagonists administered to
animals with cirrhosis reverse the water retention. Human studies using orally
active, non-peptide-selective V2 receptor antagonists in patients with cirrhosis
are currently underway. Pregnancy is another state of nitric oxide-mediated
arterial vasodilation that is associated with plasma AVP concentrations that are
relatively high for the degree of hypoosmolality. Upregulation of the water
channel aquaporin-2 in the renal papillae of pregnant rats has also been
demonstrated, and this effect is reversed by administration of a V2 receptor
antagonist.
PMID- 9756092
TI - Angiotensin II and bradykinin regulate the expression of P-selectin on the
surface of endothelial cells in culture.
AB - Cell-surface expression of endothelial P-selectin increases adhesion and
migration of leukocytes and thus may participate in the pathogenesis of
reperfusion injury and atherosclerosis. Angiotensin II (Ang II) is also thought
to be involved in such disease states. Nitric oxide (NO) downregulates P-selectin
expression, and bradykinin (BK) is known to stimulate NO release from endothelial
cells. The objective of this study was to determine the effects of 10-min
stimulation of cultured human umbilical endothelial cells (HUVECs) with Ang II,
BK, or both on P-selectin expression. Ang II (10(-9)-10(-5) M) stimulated P
selectin expression in a concentration-dependent manner, exhibiting a significant
effect at 10(-7) M and reaching a plateau at 5 x 10(-5) M. Pretreatment of HUVECs
with the AT1 antagonist losartan and the AT1/AT2 antagonist saralasin but not the
AT2 antagonist PD123319 (all at 10(-5) M) markedly attenuated the effect of 10(
7) M Ang II. The effects of Ang II on P-selectin expression were not affected by
the presence of the NO synthase inhibitor nitro-L-arginine (L-NA, 5 x 10(-4) M)
but were abolished by pretreatment with superoxide dismutase (SOD). BK (10(-6) M)
abolished the effects of 10(-7) M Ang II on P-selectin expression but did not
affect P-selectin expression induced by desmopressin (0.01-10 microM). L-NA
obliterated the blunting effect of BK on the Ang II-induced P-selectin membrane
expression. BK alone slightly stimulated P-selectin expression, but in the
presence of L-NA, BK markedly enhanced P-selectin expression. The effects of BK
in the presence of NA were not altered by SOD, indicating that at difference with
Ang II, it acts by a mechanism other than superoxide generation. Thus, Ang II
acting on AT1 receptors stimulates superoxide generation, which, in turn, induces
expression of P-selectin on the endothelial cell surface. BK inhibits the effects
of Ang II, likely acting via NO. We conclude that the balance between Ang II, BK,
and NO can regulate P-selectin expression on the endothelial cell membrane, an
important component of the cascade leading to leukocyte adhesion to the vascular
endothelium.
PMID- 9756093
TI - Streptozotocin, an analog of N-acetylglucosamine, blocks the removal of O-GlcNAc
from intracellular proteins.
AB - Streptozotocin (STZ), an analog of N-acetylglucosamine (GlcNAc), is a specific
toxin for the pancreatic beta cell. We found that treatment of rats with STZ
results in an early beta-cell-specific increase in the level of intracellular
protein modification by O-linked GlcNAc (O-GlcNAc). Using a model O-GlcNAc
peptide based on the transcription factor Sp1, we show that treatment of cultured
cells with STZ during peptide biosynthesis results in hyperglycosylation of the
peptide as a result of the ability of STZ to specifically inhibit the activity of
O-GlcNAc-selective N-acetyl-beta-D-glucosaminidase. Although this inhibitory
activity of STZ probably can occur in all cells, we found, using in situ
hybridization, that beta cells express very high levels of the mRNA encoding the
enzyme responsible for cytoplasmic protein O-glycosylation, O-GlcNAc transferase
(OGT). These findings suggest that the pancreatic beta cell is particularly
sensitive to the toxicity of STZ because it expresses such high levels of OGT.
When STZ blocks O-GlcNAc removal from intracellular proteins, the cell with the
most rapid on-rate for O-GlcNAc, the beta cell, will experience the most rapid
accumulation of this protein modification. Because we also show that the on-rate
of O-GlcNAc is substrate driven in several cell types, we speculate that the beta
cell, with its high level of OGT, may also respond to elevations of blood sugar
with increased protein modification by O-GlcNAc. Thus, this proposed mechanism of
STZ toxicity on the beta cell may result from an exaggeration of a heretofore
unrecognized physiological response to glucose mediated through the high level of
OGT in these cells.
PMID- 9756094
TI - Presidential address: meeting the challenge of change.
PMID- 9756095
TI - Presentation of the 1998 Kober Medal to Eugene Braunwald.
PMID- 9756096
TI - Morphogenesis of the hypothalamus and hypophysis: their association, dissociation
and reassociation before and after "Rathke".
AB - Recent progress in the experimental morphology of the development of amphibian
pituitary gland is reviewed. A series of transplantation experiments were carried
out using wild-type embryos of the toad as a donor and albino embryos as a
recipient. Melanin granules in the wild-type cells allowed tracing of the
developmental fate of the grafts as a visible cell marker. These studies have
demonstrated that the pituitary gland is not a stomodeal derivative, as it has
long been believed to be under the name of "Rathke's pouch". The adenohypophysis
is of neural origin. The anterior part of the neural ridge (ANR) in the
neuroectoderm of the open neurula gives rise to the whole adenohypophysis, i. e.,
pars distatis, pars intermedia and pars tuberalis. The presumptive hypothalamus
is apposed caudally to the pituitary primordium. A part of the ANR contributes
neurons to the preoptic hypothalamus even after closure of the neural tube. The
anlagen of the olfactory system, which include the nasal epithelia and the
olfactory bulbs, are situated on both sides of the pituitary primordium in the
neural ridge. In both hypothalamic-hypophyseal and olfactory systems, the
peripheral and central parts derive from closely affiliated cell populations,
suggesting their clonal relationships. Development of the hypophysis and
hypothalamus is interdependent. On one hand, a connection with the embryonic
hypothalamus is essential for the pituitary proopiomelanocortin cells to develop.
On the other hand, neither the hypothalamic median eminence nor its axonal supply
develops without the presence of the pituitary primordium. Novel aspects of the
ontogeny and phylogeny of these organs are discussed with special reference to
the role of the neural ridge in the generation of a spectrum of chemoreceptive
organs.
PMID- 9756097
TI - Immunoelectron microscopic identification of lysozyme-expressing cells in human
labial salivary glands.
AB - Although human labial gland secretions contain serous components such as the
bactericidal enzyme, lysozyme, the presence of serous cells in this gland has yet
to be clearly visualized under the electron microscope. The present study
identifies lysozyme-expressing cells of the labial glands using microwave-fixed,
Epon-Araldite-embedded specimens, which showed excellent preservation of both
ultrastructural detail and antigenicity for post-embedding immunogold labeling of
lysozyme. Ultrastructurally, all of the secretory cells of the glands appeared to
be a mucous-type and have a serial maturation relationship, consistent with a
previous report by TANDLER et al. (1969a): their secretory granules were electron
lucent and exhibited reactivity for mucus staining by the periodic acid
thiocarbohydrazide-silver proteinate (PA-TCH-SP) method. We classified them into
two immature types (I, II) and two mature types (I, II). Their distinctive
features were the following: 1) relatively small (0.5-1 microm) secretory
granules and well-developed basal rough endoplasmic reticulum for the immature
types; 2) larger (1-2 microm) secretory granules and well-developed Golgi
apparatus, which showed intense PA-TCH-SP reactivity in the 2-3 trans-cisterns,
for the mature types; 3) few secretory granules in the immature type I; and 4)
the darkest appearance for the mature type II. Immunogold labeling with anti
lysozyme showed specific labeling of the two immature-type cells, in which gold
particles were found mainly over the secretory granules and Golgi apparatus, and
moderately over the rough endoplasmic reticulum. In the secretory granules, the
labeling was distributed throughout the contents and was present even if they
showed strong PA-TCH-SP reactivity; in the Golgi area, it was seen over the
stacked cisternae, trans-Golgi networks, and condensing vacuoles. No specific
labeling was seen in the mature-type cells or in the duct cells. These immature-
and mature-type cells were almost equivalent to the "serous demilune or acinus"
and "mucous tubule" cells, respectively, at the light-microscopic level. These
results indicate that the traditional "immature mucous-type cells" of the human
labial glands produce lysozyme and should be classified as seromucous cells.
PMID- 9756099
TI - Localization of cytoplasmic free calcium ions in PC12 cells with varicose fibers.
AB - Differentiated PC12 cells with varicose fibers were used as a model of
sympathetic neurons to demonstrate the intracellular localization of cytoplasmic
free calcium ions. Changes in the concentration of cytoplasmic free calcium ions
were analyzed at individual varicosities upon stimulation with acetylcholine by
laser scanning confocal microscopy. Transient increases in cytoplasmic free
calcium ion concentration were localized in the varicosities and recognized in
both the absence and presence of extracellular Ca2+. Immunocytochemical analysis
of intracellular calcium channels, 1, 4, 5-trisphosphate receptors and ryanodine
receptors, by electron microscopy demonstrated that immunoreactive sites were
mainly localized in large dense core vesicles in the varicosities and neurites.
These results suggest that the exocytosis of large dense core vesicles is
regulated by an increase in cytoplasmic free calcium ion concentration from an
intracellular Ca2+ store.
PMID- 9756098
TI - Identification of arterial and venous segments of blood vessels using alkaline
phosphatase staining of ink/gelatin injected tissues.
AB - The present study describes a method for discriminating between the arterial and
venous segments of blood vessels in mouse tissues and organs using alkaline
phosphatase (ALPase) staining of ink/gelatin injected tissues. Anesthetized mice
were injected through the left ventricle with blue ink/gelatin, and various
organs and tissues were removed from the body and fixed by immersion in 10%
formalin. Sections 50-100 microm thick were incubated for ALPase in a medium
containing naphthol AS-BI phosphate and fast red TR by the azocoupling method. In
such specimens as the brain and skeletal muscles, ALPase activity was found in
arterioles and capillaries on the arterial side, whereas it was absent in
capillaries on the venous side and in venules. In the liver, only branches of the
hepatic artery were positive. ALPase activity was absent in the vessels of the
lung except for a positive reaction in branches of the bronchial arteries. These
findings indicate that the ALPase activity is confined to the arterioles and
arterial segments of the capillaries in the systemic circuit. Thus, ALPase
staining of ink/gelatin injected specimens is a useful method for differentiating
the arterial and venous segments of the micro-vascular bed in various organs and
tissues in mice.
PMID- 9756100
TI - MAP2 and GAP-43 expression in normal and weaver mouse cerebellum: correlative
immunohistochemical and in situ hybridization studies.
AB - MAP2 is a major microtubule-associated brain protein, selectively localized in
dendrites; growth-associated phosphoprotein GAP-43 is a neuron-specific protein
associated with axonal outgrowth. In adult cerebellum, both of these proteins and
their corresponding RNA transcripts are most strongly expressed by granule cells.
Using immunocytochemistry with antibodies and in situ hybridization
histochemistry with [32P] labeled oligonucleotide probes, we examined the
cellular localization of MAP2, GAP-43 and their mRNAs in the cerebellum of
control and weaver (wv/wv) mutant mice, which exhibit massive granule cell death.
In wild-type (+/+) mice, MAP2 immunoreactivity was seen in neuronal somata and
dendrites of the granule cell layer; GAP-43 immunoreactivity was present in
molecular layer, corresponding to the distribution of parallel fibres.
Transcripts encoding MAP2 and GAP-43 were localized in the layer of the granule
cell somata. In heterozygous weaver mice (wv/+), which feature an intermediate
degree of granule cell loss, MAP2 immunoreactivity was localized in the granular
layer, and the pattern of GAP-43 immunostaining was also similar to +/+, the only
difference being a thinner molecular layer. Heterozygotes had an anatomical
pattern of MAP2 and GAP-43 mRNA hybridization qualitatively similar to that of
the wild-type with some deviations in signal intensity. In homozygous weaver
mutants (wv/wv), MAP2 immunoreactivity was extremely weak in the area beneath
Purkinje cells and a certain GAP-43 immunoreactivity was seen in the upper part
of cerebellar cortex. Hybridization signals for MAP2 and GAP-43 mRNAs were
minimal. The reported alterations in regional pattern of MAP2 and GAP-43
expression in mutant mice offer a molecular correlate of dendritic and axonal
protein gene transcription pertinent to the neuropathological manifestations of
certain forms of heredodegenerative ataxia.
PMID- 9756101
TI - Light and electron microscopic detection of anionic sites in the rat choroid
plexus.
AB - Electron microscopy of ultrathin sections stained with cationic iron colloid
revealed that, in the choroid plexus of the rat brain ventricles, the luminal
surface and fenestral diaphragm of the capillary endothelium as well as the
basement membranes of the endothelium and epithelium are strongly anionic or
intensely negatively charged. The iron colloid reaction to these anionic sites
was erased by treatment with hyaluronidase or digestions with chondroitinase
ABC/heparitinase/keratanase. These results indicate that sulfated proteoglycans
provide such anionic sites of the choroidal capillaries. Discussion suggested
that the negative charge on the luminal surface of the capillary endothelium
prevents the adhesion of blood cells to capillary walls and also prevents
endothelial adhesion by their repelling each other. It was further discussed that
the negatively charged endothelial fenestrae and basement membranes may act as a
charge barrier to inhibit the passage of anionic molecules.
PMID- 9756102
TI - Electron microscopic characterization of filiform papillae in the normal human
tongue.
AB - The fine structure of filiform papillae on the normal human tongue was examined
level by level, from the basal layer to the surface, in specimens taken from the
dorsal side of the lingual body. Human lingual epithelia showed three distinct
regions: epithelia on the anterior and on the posterior sides of filiform
papillae and an interpapillary epithelium. While the basal and the squamous cell
layers were similar throughout these three regions, differences were noted in the
granular and the horny layers. The interpapillary epithelium actually lacked both
the granular and the horny layers. The epithelium on the anterior side of
filiform papillae was characterized by alternating layers of granular cells and
of cornified cells. Granular cells possessed three types of keratohyaline-like
granules within their cytoplasm: uniformly electron dense, relatively less
electron dense, and a heterogeneous type. While the number of the keratohyaline
like granules was remarkably diminished in the epithelium on the posterior side
of filiform papillae, a considerable amount of tonofibrils was present in the
cytoplasm. In the uppermost portion of the anterior side of filiform papillae,
coherence between adjacent epithelial cells depended mainly on the interlocking
of cytoplasmic villi and poorly developed desmosomes on villi. On the other hand,
epithelial cells on the posterior side of filiform papillae appeared to be more
tightly adhesive compared with those on the anterior side. This was due to focal
thickening of the plasma membrane and to desmosomes at the interface between the
granular and cornified cells, and to the formation of a marginal band and
increased intercellular cement presumably derived from lamellar bodies in the
horny layer. These findings demonstrate distinct differences between the anterior
and the posterior sides of filiform papillae in the human tongue with respect to
keratinization patterns, structures associated with cell-to-cell adhesion and the
strength of cellular cohesion in the uppermost portion, and the turnover of
cornified cells. These differences may contribute to the formation of the unique
external configurations of filiform papillae.
PMID- 9756103
TI - Acellular calcified columns in the normal growth plate of mouse vertebrae.
AB - The present study aims to demonstrate the calcified columnar structures of the
growth plate of mouse vertebrae and to show their age related changes. For light
microscopy, paraffin sections of decalcified lumbar spines were stained with
hematoxylin-eosin or toluidine blue; methacrylate sections of undecalcified
specimens were stained to detect calcium precipitate. For scanning electron
microscopy, lumbar spines treated with 5% NaClO solution were dehydrated by
acetone and metal-coated. Light microscopy of hematoxylin-eosin stained sections
revealed that the acellular columnar structures appeared between the chondrocyte
stacks in the growth plate. These structures were stained more densely by
toluidine blue. The methacrylate-embedded sections for calcium staining showed
calcium deposition in the columns. Scanning electron microscopy of NaClO-treated
specimens enabled the direct observation of the columns on both the epiphyseal
and diaphyseal bone surfaces facing the cartilaginous growth plate. Numerous
projections on each surface were distributed in mirror images ; the corresponding
projections were similar in size and shape, indicating that the projections
bonded with each other and formed calcified columns in the cartilaginous growth
plate. Longitudinal sections of the spine confirmed these findings. The calcified
columns first appeared about 2 or 3 weeks of age and increased in number with
time. While increasing in number, they also grew in size fusing with the
neighboring ones. The proportional area of the columns occupying the surface
facing the growth plate also increased with age. These findings indicate that the
calcified column ultimately concerns the cessation of the bone growth.
PMID- 9756104
TI - Lymphatic drainage of the cerebrospinal fluid from monkey spinal meninges with
special reference to the distribution of the epidural lymphatics.
AB - The structural organization of the epidural lymphatics and lymphatic drainage of
the cerebrospinal fluid from spinal meninges was studied in Japanese monkeys
(Macaca fuscata) by an enzyme-histochemical method. The spinal meninges were
examined at various intervals from 1 to 48 h, as well as at 30 days, following an
injection of ultrafine carbon particles into the subarachnoidal space (cisterna
magna). Lymphatics were differentiated from blood capillaries by the 5'
nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) double staining method (KATO
et al. 1991, 1993) both in the whole-mount preparations and tissue sections.
Carbon-filled collecting lymphatics and lymph nodes constantly appeared in the
cervical and thoracic regions but only rarely in the lumbo-sacral region after
carbon injection. Networks of 5'-Nase-positive lymphatics in the epidural
connective tissues were seen in a large area on the dorsal surface around each
spinal nerve root in the cervical and upper thoracic regions, especially at a
level corresponding to the brachial plexus (C5-Th1). Carbon particles were often
found within the 5'-Nase-positive lymphatics. In the lower thoracic and lumbo
sacral regions, on the other hand, the epidural lymphatic network covered only a
small area around each spinal nerve root. These findings suggest that the
epidural lymphatics are well developed on the dorsal side of the lower cervical
spinal dura mater and may function as an absorptive pathway for the cerebrospinal
fluid from the subarachnoidal space.
PMID- 9756105
TI - Non-pharmacological modification of cardiac risk factors: part 3. Smoking
cessation and alcohol consumption.
AB - Smoking cessation (SC) is probably the single most important risk factor
modification for both primary and secondary prevention of cardiovascular disease.
Interventions to stop smoking are highly cost effective. SC produces reductions
in mortality and morbidity that generally outweigh any increase in risk due to
weight gain, unless the gain is so great that it is accompanied by adverse
changes in blood pressure, lipid profile or glucose tolerance. There is clear
evidence that SC improves the lipid profile, decreases thrombotic tendency,
reduces vascular endothelial damage and improves insulin sensitivity.
Epidemiological studies consistently demonstrate a reduced risk of developing
coronary heart disease (CHD) with moderate alcohol consumption (showing
protection at < or = 2 drinks per day), but an increased risk at higher alcohol
consumption levels. Potential mediators of these cardioprotective effects include
an increase in high-density cholesterol (HDL-C), decreased clotting propensity,
enhanced insulin sensitivity and glucose tolerance, and a possible lowering of
blood pressure at low consumption levels in women. Alcohol consumption may not,
however, compensate for the large increase in risk produced by smoking. Whereas
moderate alcohol consumption slightly reduces the risk of death between the ages
of 35 and 69 years, cigarette smoking approximately doubles the risk.
PMID- 9756106
TI - Cefepime--assessment of its need at a tertiary care center.
AB - OBJECTIVE: To assess the need and possible indications for a fourth-generation
cephalosporin (cefepime). METHOD: A cohort study was carried out over a 17-month
period in a 1500-bed Swiss university hospital. RESULTS: In 256 (22.6%) of the
1135 patients followed consecutively by our Infectious Diseases Division,
cefepime could have been chosen as an alternative to other broad-spectrum
antibiotics, including imipenem/cilastatin (n=94), ciprofloxacine (n=52) and
ceftazidime (n=49). Considering the low price-strategy of the pharmaceutical
company promoting this drug in Switzerland, there would have been considerable
cost savings for the hospital pharmacy if cefepime had been used as first-line
treatment in these occasions. Nevertheless, we could not observe any potential
advantage of cefepime compared to already introduced broad-spectrum antibiotics,
except that cefepime was effective against infections caused by Enterobacter spp.
resistant to ceftazidime. CONCLUSION: We conclude that fourth-generation
cephalosporins such as cefepime may be introduced into large hospitals only after
careful assessment of their potential benefits and that consultation by an
Infectious Diseases Division is useful when evaluating the need for new broad
spectrum antibiotics in the hospital setting.
PMID- 9756107
TI - Placental transfer and neonatal effects of propofol in caesarean section.
AB - OBJECTIVE: To assess transplacental passage of propofol by measuring the levels
in maternal and foetal plasma, and the possible relationship between the latter
and the neonatal effects when propofol is used as an induction agent in obstetric
anaesthesia for performing a caesarean section to terminate pregnancy. METHODS:
Intravenous propofol was administered as an anaesthesia-inducing agent at doses
of 2 mg/kg in 10 healthy women (ASA I-II). The propofol concentrations were
measured by high-performance liquid chromatography (HPLC). RESULTS: After
induction, hypnosis was achieved in all patients within 75 s, and it took 4-10
min to deliver the foetus. Apgar test scores were high in seven of the 10
neonates, in three cases the score was 5 or less. The mean values in venous
maternal blood were 5.01+/-1.06 microg/ml 1 min after propofol administration and
1.47+/-0.35 microg/ml at the time of delivery. Propofol crossed the placental
barrier with levels in the umbilical cord of 0.32+/-0.10 microg/ml in the vein
and 0.22+/-0.08 microg/ml in the artery. CONCLUSION: Propofol plasma levels in
the newborn at the time of delivery depend on the level in maternal plasma, and
therefore on the dose used for induction and the time lapsed between the
administration of the drug and the delivery of the foetus.
PMID- 9756108
TI - Serum uric acid levels in cardiovascular diseases.
AB - OBJECTIVE: Comparison of the serum uric acid levels of healthy people (n=71) and
patients with cardiovascular diseases (CVD) (n=62). SUBJECTS AND METHODS: The
patients included had either experienced acute myocardial infarction (AMI)
(n=31), atherosclerosis (AT) (n=23) or ischaemia (n=8). The mean values (x+/-SD)
of serum uric acid levels of the control group, the patients with CVD as a whole,
and patients with AMI, AT and ischaemia were 4.15+/-0.45 mg%, 5.6+/-2.06 mg%,
5.96+/-2.60 mg%, 5.38+/-1.22 mg% and 4.94+/-1.40 mg%, respectively. A
statistically higher level of serum uric acid was found in the controls compared
to the CVD patients (P < 0.05). CONCLUSION: The higher serum uric acid levels
found in CVD patients suggests that any protective antioxidant effect which uric
acid has is overwhelmed by other negative effects on pathogenesis.
PMID- 9756109
TI - Valproic acid clearance in children with epilepsy.
AB - OBJECTIVE: To evaluate population pharmacokinetics and the relationship between
plasma concentration and daily dose of valproic acid (VPA) in a homogeneous group
of children with epilepsy. METHODS: One hundred and fifty-one steady-state VPA
plasma level measurements were made in 62 children aged 8 months to 6 years who
were receiving VPA monotherapy. RESULTS: The level:dose ratio increased with age,
its mean value was 1.7 in children aged under 2 years, 2.1 in children aged 2.4
years and 3.3 in children aged 4.6 years. Weight-adjusted values of VPA clearance
(Cl) decreased with increasing age. The Cl values in these three age groups were
24.5+/-12.4 ml/kg/h, 19.9+/-6.1 ml/kg/h and 12.7+/-3.0 ml/kg/h, respectively. The
relationship between VPA clearance and age was: Cl (ml/kg/h)=47.6 x age (months)(
0.29), (r=-0.87). This equation allows the estimation of VPA plasma clearance on
the basis of the child's age, within the range 8-72 months. Therefore, it can be
used to establish the initial maintenance paediatric dose of VPA in monotherapy.
CONCLUSION: The relationship between clearance and age should be useful when
establishing a pharmacokinetic programme for VPA monotherapy in children.
PMID- 9756110
TI - Whole saliva and plasma levels of clozapine and desmethylclozapine.
AB - BACKGROUND: Therapeutic drug monitoring of clozapine as an aid in the treatment
of schizophrenic states is commonly used in our hospital. OBJECTIVE: Development
of a high-performance liquid chromatographic method for the determination of
clozapine (CLZ) and its major metabolite desmethylclozapine (DMCLZ) in plasma and
saliva, and investigation of the relationship between plasma concentrations of
CLZ and DMCLZ and concentrations in saliva in patients treated with clozapine.
METHODS: Subjects were either inpatients or outpatients with a DSM IV diagnosis
of schizophrenia (n=34). Determination of CLZ and DMCLZ saliva concentrations
appeared to be a satisfactory method to check compliance to treatment,
particularly in outpatients. RESULTS: Mean CLZ and DMCLZ plasma concentrations
were 432+/-264 ng/ml (+/-SD) (range 90-1310 ng/ml) and 257+/-144 ng/ml (range 55
580 ng/ ml), respectively. The CLZ/DMCLZ plasma ratio was equal to 1.7+/-0-5
(daily dosage 7.2+/-2.3 mg/kg, n=34). Mean CLZ plasma and saliva levels were
336+/-157 ng/ ml (range 90-580 ng/ml) and 159+/-86 ng/ml (range 40-364ng/ml),
respectively (r=0.56, n=14). Mean DMCLZ plasma and saliva levels were 196+/-112
ng/ ml (range 55-481 ng/ml) and 109+/-67ng/ml (range 40-250ng/ml), respectively
(r=0.73, n=14). Mean CLZ/DMCLZ ratios determined in plasma and saliva were 1.9+/
0.6 (range 1.0-3.4) and 1.7+/-0.6 (range 1.0-3.2), respectively (r=0.85, n=14).
CLZ and DMCLZ saliva concentrations appear to be useful for checking compliance
to treatment, in particular among outpatients.
PMID- 9756111
TI - Stability of cefazolin sodium eye drops.
AB - OBJECTIVE: Assessing the stability of cefazolin sodium in preservative-free and
preservative-containing eye drops. METHOD: Extemporaneous formulations of eye
drops were prepared from a commercially-available parenteral product of cefazolin
sodium: eye drops 'A' contained 50mg/ml of cefazolin sodium in 0.45% w/v sodium
chloride solution, and eye drops 'B' contained 50 mg/ml, 0.005% w/v thiomersal
and 1% w/v glycerol in water-for-injection. Cefazolin sodium concentrations in
these eye drops were monitored by a stability-indicating HPLC assay method.
Measurements of pH and osmolality, as well as tests for microbial contamination,
were conducted. RESULTS: The eye drops stored at 4 degrees C were stable for 42
days with minimal changes in pH and osmolality, but eye drops stored at room
temperature were only stable for a few days with greater increments in pH and
osmolality. None of the samples cultured had bacterial or fungal growth after 7
days of incubation. CONCLUSION: Extemporaneously prepared formulations of
cefazolin are unstable at room temperature and should be stored in a
refrigerator.
PMID- 9756112
TI - Evaluation of drug usage and expenditure in a hospital diabetes clinic.
AB - BACKGROUND: Diabetes mellitus is a major public health problem and often coexists
with hypertension and dyslipidaemia. A prescription-based survey was conducted to
examine the use of antidiabetic, antihypertensive and lipid lowering drugs in a
hospital diabetes clinic. The expenditure incurred was also evaluated. METHOD:
Prescriptions issued from the diabetes clinic were collected for 4 consecutive
weeks. Drugs were categorized into three main classes--antidiabetic,
antihypertensive and lipid-lowering drugs. The unit cost of each drug and the
total amount prescribed were used to estimate the total drug costs. RESULTS:
During the 4-week study period, 534 prescriptions were collected, of which 520
contained antidiabetic drugs. Oral hypoglycaemic agents were prescribed in 379
patients (72.9%). Sulphonylurea was used as a single agent in 119 (22.9%)
patients, in combination with metformin in 219 (42%) patients and with insulin in
17 patients (3.3%). Among patients treated with sulphonylureas (n=342),
glibenclamide (47.7%) and gliclazide (30.7%) were the main drugs prescribed.
Metformin monotherapy was prescribed in only 31 patients (6%). Insulin treatment
was prescribed in 141 (27%) patients and in combination with oral drugs in 23
patients (4.5%). Of the 534 prescriptions, 225 (42%) contained antihypertensive
drugs. Calcium channel blocking agents and angiotensin converting enzyme
inhibitors were the most commonly prescribed drugs in both monotherapy (n=155)
and combination therapy (n=70). The antidiabetic and antihypertensive drugs
accounted for 45% and 39% of the total drug expenditure, respectively. Lipid
lowering drugs were prescribed in 8% of the diabetic patients. Simvastatin and
gemfibrozil were the most common drugs prescribed and accounted for 12% of the
total drug expenditure. CONCLUSION: The use of antidiabetic drugs represents a
major burden on the health care system. The high proportions of patients
requiring antihypertensive drugs and lipid lowering drugs further increase drug
expenditure. Most of these treatments have been shown to improve clinical
outcomes and quality of life, if used appropriately. The impacts of these long
term medications on health care financing require careful evaluation to assess
their cost-effectiveness.
PMID- 9756113
TI - Naproxen incorporated lipid emulsions. I. Formulation and stability studies.
AB - BACKGROUND: Intravenous lipid emulsions stabilized with phospholipids have been
an attractive alternative as vehicles for drug delivery, particularly for the
parenteral administration of drugs with solubility problems. METHODS: Naproxen (a
poorly aqueous soluble non-steroidal anti-inflammatory agent) emulsions were
formulated with different types of emulsifiers (soybean lecithin, synperonic PEF
127 and a 50:50 mixture of these). The stability of the various emulsion systems
was evaluated at different temperatures (4, 25 and 40 degrees C) for a period of
6 months by measuring changes in pH, droplet size, viscosity and percentage oil
separation. The percentage of naproxen incorporation and the degree of haemolysis
induced by the different types of emulsion systems was also determined. RESULTS:
The emulsifier type showed a pronounced effect on the physicochemical properties
of the emulsion systems, whereas storage temperature and time did not.
Irrespective of emulsifier type, storage temperature and time, the percentage
incorporation of naproxen in emulsions was between 80 and 100%. The degree of
haemolysis induced by other emulsion components (dimethylsulfoxide (DMSO) and
naproxen solution in DMSO) was about 10 times higher than that induced by
emulsion systems. CONCLUSION: Choice of emulsifier is the most important factor
in the stability of the naproxen emulsions.
PMID- 9756114
TI - Compatibility and stability of fentanyl admixtures in polypropylene syringes.
AB - OBJECTIVE: To determine the physicochemical stability of fentanyl in combination
with midazolam and either hyoscine butylbromide or metoclopramide, and stored in
30 ml polypropylene syringes. METHODS: Solutions containing approximately 40
microg/ ml of fentanyl in combination with midazolam (approximately 600
microg/ml) and either metoclopramide (approximately 700 microg/l) or hyoscine
(approximately 850 microg/ml) were prepared from commercial ampoules of the
drugs. The solutions were stored, in triplicate, in the dark at 32 degrees C (to
simulate usage conditions) for 10 days, and the concentration of each constituent
drug was periodically determined using a stability-indicating high-performance
liquid chromatography assay. RESULTS: The combinations were relatively stable,
with all drugs maintaining over 90% of their initial chemical potency for at
least 1 week. There were no evident changes in either the physical appearance or
pH values of the solutions over the course of the study. CONCLUSIONS: On the
basis of physicochemical stability, polypropylene syringes containing fentanyl
with midazolam and either hyoscine butylbromide or metoclopramide can be safely
prepared and stored at or below 32 degrees C for periods of up to 1 week prior to
use by palliative care patients receiving the drugs via a portable subcutaneous
infusion device.
PMID- 9756115
TI - Effective utilization of erythropoietin with intravenous iron therapy.
AB - INTRODUCTION: Iron replacement therapy reduces the demand for erythropoietin
(EPO) in some dialysis patients. It has been postulated that iron supply to the
bone marrow is a rate-limiting step in the process of erythropoiesis under
erythropoietin stimulation. METHODS: We evaluated the economic benefit of
intravenous iron therapy for this purpose in a prospective, non-blinded study of
22 haemodialysis patients, 16 male, six female, mean age 62 years (range 24-80
years). All patients had a serum ferritin (SF) of < or = 60 microg/L, despite
oral iron therapy. Patients with high aluminium and/or parathyroid hormone (PTH)
levels, underlying bleeding/haematological disorders or active inflammatory
diseases were excluded. Patients were established on subcutaneous EPO and given
intravenous iron over seven consecutive dialysis sessions (total dose 1050 mg)
and supplemental monthly doses with regular monitoring for 4 months. RESULTS: The
median EPO dose was 4000 units/week (mean 6050 units/week) pre-treatment and 2000
units/week (mean 3700 units) at 6 weeks post intravenous iron therapy (P=0.03).
No serious adverse events occurred in the 154 treatment sessions of intravenous
iron. Mean haemoglobin (Hb) level remained constant at 6 and 12 weeks (P=0.087).
Serum ferritin levels (P< 0.0001) rose significantly, while a reduction in
transferrin saturation (TS) became significant at the end of the study
(P=0.0047). The use of intravenous iron allowed a substantial monthly cost saving
per patient in our unit. CONCLUSION: Intravenous iron therapy is a safe and cost
effective method for maintaining or improving Hb levels with a more effective
utilization of EPO in patients with low SF levels despite oral iron therapy.
PMID- 9756116
TI - Verapamil and acute dystonia.
PMID- 9756117
TI - Iron stores in man in relation to diet and iron requirements.
AB - OBJECTIVE: To calculate iron stores in man and their rates of changes in relation
to iron requirements and dietary iron intake and bioavailability. METHOD: Newly
established relationships between iron absorption from whole diets and serum
ferritin (SF) and between SF and iron stores allow calculations of amounts of
stored iron under different conditions (diets, losses) at stationary states when
absorption equals losses. Rate of growth of stores can also be calculated. All
calculations are based on observations and require no model assumptions. RESULTS:
Present calculations of iron stores agree with previously observed phlebotomy
values. Differences in intake and bioavailability of dietary iron and in iron
requirements had marked effects on amounts of stored iron. A wide range of diets
was studied, from a hypothetical high-meat diet typical for early man to diets in
developing countries. A new equation is given for the translation of SF into iron
stores. Analyses of growth rate of stores under different conditions showed a
fast growth from zero iron stores during the first year (reaching about 80% of
final amounts) followed by a much slower rate for 2-3 y. A marked inertia was
seen in rate of changes in iron stores that was more marked the closer stores
were to their stationary states making it difficult to use SF to estimate short
term changes in iron absorption in iron replete subjects. CONCLUSIONS: Realistic
Western-type diets with good bioavailability can cover iron requirements in most
women and can restitute iron stores during lactation. The high prevalence of iron
deficiency in menstruating Western women is thus mainly related to a further low
bioavailability of iron in present diets. Present analyses also demonstrated an
effective control of iron absorption preventing development of iron overload in
otherwise healthy subjects even if the diet is fortified with iron and even if
meat intake is high.
PMID- 9756118
TI - Could antioxidants play a role in high rates of coronary heart disease in the
Czech Republic?
AB - OBJECTIVES: To compare plasma levels of antioxidant vitamins in the Czech
population with those in a western European population, and to investigate
whether plasma levels of antioxidant vitamins in Czech population are related to
risk of MI. DESIGN: The study has two parts: a cross-sectional survey and a
population based case-control study. SETTING: Adult population in two districts
of the Czech Republic, and London based civil servants group as the comparison.
SUBJECTS: A random sample of men and women aged 25-64y resident in two districts
were selected for the cross- sectional survey. Subjects in the age group 40-49 y
were compared to a sample of British civil servants of the same age enrolled in
the Whitehall II Study. Men in the Czech sample served as controls to 52 male
cases of first non-fatal myocardial infarction (MI) which occurred in the same
population. Plasma samples were obtained from venepuncture during an interview in
hospital in the population sample and immediately after hospitalization in the MI
cases. MAIN OUTCOME MEASURES: Plasma levels of beta-carotene and alpha
tocopherol, and the event of MI. Identical protocol and one laboratory was used
for all analyses. RESULTS: The mean plasma levels of beta-carotene and alpha
tocopherol in healthy Czech men and women were substantially lower than in a
subsample of British civil servants examined in the same laboratory. Smoking was
strongly related to beta-carotene in both populations but differences between
Czechs and Brits were present in both smokers and non-smokers. In the case
control study among Czech men, low levels of the vitamins were strongly related
to an increases risk of MI. Age-adjusted odds ratios for concentrations below the
median were 3.33 (95% confidence interval 1.43-8.33) for beta-carotene and 1.89
(0.94-3.45) for alpha-tocopherol; further adjustment for a range of variables
reduced these estimates only slightly. CONCLUSIONS: Plasma concentrations of
antioxidants in the Czech population appeared to be very low, and men with low
levels of these substances are at increased risk of MI. This indicates that sub
optimal intake of antioxidants or related dietary factors may have played a role
in the high rates of coronary heart disease in this population.
PMID- 9756119
TI - A community based study of vitamin A and vitamin E status of adolescent girls
living in the Shire Valley, Southern Malawi.
AB - OBJECTIVE: To assess vitamin A and E status and anaemia in non-pregnant Malawian
adolescent girls. DESIGN: A cross-sectional study in rural village communities in
the Shire Valley, Southern Malawi. SUBJECTS: Adolescent girls, n = 118, aged
between 10 and 19 y, 112 of whom were unmarried. METHODS: Socio-demographic
information was collected by questionnaire, heights and weights were measured.
Vitamin A was assessed by the Modified Relative Dose Response (MRDR) test, in
addition to serum retinol values. Blood samples were collected 4-5 h after
administration of 3,4-didehydroretinyl acetate. Retinol and alpha-tocopherol
levels were measured by HPLC. Serum retinol results for non-pregnant girls were
compared with values for 43 adolescent pregnant girls which were available from a
previous study. RESULTS: 26.6% of non-pregnant girls had serum retinol values <
0.70 micromol/L; 40.2% had an MRDR ratio > 0.060. In 59.3%, serum tocopherol
levels were < 11.5 micromol/L and the tocopherol/cholesterol ratio was < 2.2 in
23.9%. 11.3% had a haemoglobin > or = 12 g/dl. Vitamin A levels were
significantly related to age, and younger girls were more likely to be deficient.
Significant correlations were found between serum retinol, MRDR values and serum
tocopherol. Girls with a low body mass index for age had tocopherol cholesterol
ratios < 2.2. Low serum retinol values occurred significantly more often in
stunted girls (P=0.01). Serum retinol values of adolescent pregnant girls were
significantly lower than those of non-pregnant adolescents (P=0.002).
CONCLUSIONS: Vitamin A and E deficiency and anaemia were common in adolescent non
pregnant girls, and thought to partly result from increased growth requirements.
Girls who become pregnant at an early age are at risk of depletion of their
nutritional reserves. Measures to reduce nutritional deficiencies before the
first pregnancy are needed.
PMID- 9756120
TI - Anthropometric characteristics of older people in rural Malawi.
AB - BACKGROUND: Older people are becoming an increasingly important proportion of the
populations of developing countries, yet little information exists on their
nutritional status or social conditions. OBJECTIVE: To assess the nutritional
status of older people in rural Malawi. DESIGN: Cross-sectional study. SETTING:
Lilongwe, Malawi. SUBJECTS: A total of 296 respondents (97 males and 199 females)
aged from 55-94 y were studied. METHODS: Selected anthropometric measurements
were taken by trained personnel. Among kyphotic respondents, height was estimated
from armspan using regression equations derived from the non-kyphotic
respondents. Body mass index (BMI) and corrected arm muscle area (CAMA) were
computed using standard equations. RESULTS: The mean age of the respondents was
63.3 y and 68.9 y among females and males, respectively. Kyphosis was seen in
17.3% of all subjects and oedema in 4.1%. Nearly 90% of the subjects were
involved in agricultural activities. Men were heavier and taller than women but
women had larger MUACs and triceps skinfolds than males. The mean BMIs in kg/m2
(+/- s.d.) were as follows: 19.7 (2.6) for men and 20.3 (3.0) for women. The
prevalence of undernutrition, defined as BMI< 18.5 kg/m2, was 36.1% among males
and 27.0% among females. In contrast, using MUAC (cut-offs 23 cm for males and 22
cm for females), 20.4% of the men and only 10% of the women were classified as
malnourished. CONCLUSION: The study demonstrated for the first time that
undernutrition is a significant problem among older people in rural Malawi. It
highlights the need to incorporate older people into existing and future
nutrition and health programmes.
PMID- 9756121
TI - Effects of dietary coconut oil, butter and safflower oil on plasma lipids,
lipoproteins and lathosterol levels.
AB - OBJECTIVE: The aim of this present study was to determine plasma levels of
lathosterol, lipids, lipoproteins and apolipoproteins during diets rich in
butter, coconut fat and safflower oil. DESIGN: The study consisted of sequential
six week periods of diets rich in butter, coconut fat then safflower oil and
measurements were made at baseline and at week 4 in each diet period. SUBJECTS:
Forty-one healthy Pacific island polynesians living in New Zealand participated
in the trial. INTERVENTIONS: Subjects were supplied with some foods rich in the
test fats and were given detailed dietary advice which was reinforced regularly.
RESULTS: Plasma lathosterol concentration (P < 0.001), the ratio plasma
lathosterol/cholesterol (P=0.04), low density lipoprotein (LDL) cholesterol
(P<0.001) and apoB (P<0.001) levels were significantly different among the diets
and were significantly lower during coconut and safflower oil diets compared with
butter diets. Plasma total cholesterol, HDL cholesterol and apoA-levels were also
significantly (P< or =0.001) different among the diets and were not significantly
different between buffer and coconut diets. CONCLUSIONS: These data suggest that
cholesterol synthesis is lower during diets rich in coconut fat and safflower oil
compared with diets rich in butter and might be associated with lower production
rates of apoB-containing lipoproteins.
PMID- 9756122
TI - Body composition changes in anorexia nervosa.
AB - OBJECTIVE: To assess the body composition changes in anorexia nervosa and after
medium term recovery. DESIGN: A descriptive study. SETTING: Rome, Italy.
SUBJECTS: Twenty women affected by anorexia nervosa (AN) with a BMI [weight
(kg)/height (m2)] below 17 kg/m2 and weight-stable for at least three months,
were compared with 10 well nourished control women (CO) and nine rehabilitated
subjects (R-AN), who had a BMI above 18.5 kg/m2 stable for at least the last six
months. INTERVENTIONS: Body fat was assessed by underwater weighing, muscle mass
by urinary creatinine, total body water (TBW) by impedance parameters (50 kHz and
800 microA), skeletal mass by anthropometry and radius bone mineral density by
dual photon absorptiometry in ultra-distal (UD-BMD) and medio-distal (MD-BMD)
sites. RESULTS: The AN group, as compared to the control group, had a
significantly lower weight, body mass index (BMI kg/m2) and percent body fat (P <
0.0000). Creatinine urinary excretion was lowest in absolute term and when
expressed as creatinine height index or per kg fat free mass (FFM) (P < 0.0000);
muscle mass per kg body weight was 13% lower (P < 0.01). Ultra distal bone
mineral density (UD-BMD) was 6% lower (not significant). TBW as percent of body
weight was significant higher (P < 0.001): however TBW/FFM % was not
statistically different with large inter-individual variability. An altered
distribution of extra and intra-cellular water was suggested by the phase angle
(AN: 4.4+/-0.8 degrees; CO: 6.1+/-0.4 degrees; (P < 0.0000). In rehabilitated
anorexic patients (R-AN) the fat mass represented 53% of the weight gain. Their
creatinine excretion remained still below the mean value of the controls (P <
0.001). The impedance parameters were not significantly different between the R
AN and the CO groups, however, the phase angle of the R-AN (5.0+/-0.7 degrees)
remained lower than in the CO group, indicating that the water distribution was
still altered. CONCLUSIONS: This study shows that AN is a condition of reduced
body fat as well as of muscle mass, with a slightly reduced bone mass. In the
course of rehabilitation, most of the weight regained is represented by fat,
while the muscle mass appears to lag behind, at least in the medium term.
PMID- 9756123
TI - Sources of bias in a dietary survey of children.
AB - OBJECTIVE: To compare non-responders and responders to a dietary survey with
respect to demographic variables and intention to choose selected breakfast
foods, and to examine if there was any systematic change in number of food items
reported during a 7 d recording period. DESIGN: Cross-sectional survey. SETTING:
Molndal, Sweden. SUBJECTS: All pupils in 5th, 7th and 9th grades in the
municipality were asked to complete a questionnaire during school hours. All
those present (n = 1584, 92% of total) answered questions about lifestyle factors
and about intentions, attitudes and beliefs concerning high-fibre bread and milk
with varying fat content. All subjects in the initial sample were asked to fill
in a 7 d record of food consumed. Acceptable food records were completed by 69%
of the initial participants. RESULTS: Subjects not completing the food record
differed significantly from participants with respect to demographic, lifestyle
and dietary factors. Dropout was more common among those who reported not usually
eating breakfast and among those intending to drink whole milk for breakfast. A
decline in reported food items during the recording period was also observed.
CONCLUSIONS: Two sources of bias were observed here, one indicating significant
differences between non-participants and participants, the other suggesting the
presence of a time-dependent trend in number of recorded foods. It is likely such
biases are present in other dietary surveys involving schoolchildren, and should
be taken into consideration in the design, analysis and interpretation of such
studies.
PMID- 9756124
TI - Fermented milk products are associated to ulcer disease. Results from a cross
sectional population study.
AB - BACKGROUND: Prevalence of peptic ulcer disease has been associated to diet. Some
dietary factors seem to have bactericidal effect which may modify the risk of
peptic ulcer disease. The objective was to analyze associations between dietary
habits and peptic ulcers. DESIGN: A cross sectional population study. SUBJECTS:
One thousand, one hundred and thirty-five subjects out of 11700 randomly invited
men and women, aged 46-67 y, participating in a diet and disease study during
1991-1993. The study population comprised of 764 cases with reported peptic
ulcer, 142 with dyspeptic symptoms and 229 randomly selected controls. METHODS: X
ray examinations and endoscopies were reviewed and 332 out of 764 peptic ulcer
cases were verified. Mean daily intake of foods and nutrients were assessed with
a combined 7d menu book and a quantitative food frequency questionnaire,
including dietary supplements. RESULTS: Subjects with verified ulcer had lower
intake of fermented milk products and vegetables and higher intake of milk, meat
and bread than controls. Intake of total fat, saturated and monounsaturated fatty
acids and linolenic acid were higher in the ulcer group. Higher intake of
fermented milk products, by quintiles showed a decreased ulcer risk; odds ratio
0.82 (0.71-40.95), adjusted for covariates below. Higher intake of milk, by
quintiles, was associated with an increased risk of ulcer; odds ratio 1.17 (1.03
1.32). Smoking, foreign ethnicity and being unmarried or divorced were covariates
associated to ulcer. CONCLUSION: This study indicates the multifactorial etiology
of peptic ulcer including dietary factors. High intake of fermented milk products
was associated with decreased risk for ulcer, whereas increased risk was noted
for high milk intake.
PMID- 9756125
TI - Lipoprotein profiles and serum peroxide levels of aged women consuming palmolein
or oleic acid-rich sunflower oil diets.
AB - OBJECTIVE: To investigate the hypercholesterolemic effects of a dietary exchange
between 16:0 and 18:1 while 18:2 was at relatively lower level (approximately 4%)
in aged women with initially high total serum cholesterol (TC) and low density
lipoprotein cholesterol (LDL-C) values and with high intakes of dietary
cholesterol. DESIGN: Subjects were assigned to two consecutive 28 d periods. In
the first period all subjects followed an oleic acid-rich diet in the form of
oleic acid-rich sunflower oil. This was followed by a second period rich in
palmitic acid in the form of palmolein. Nutrient intakes, serum lipids,
lipoproteins, antioxidant vitamins, peroxides and LDL-peroxides were measured at
two dietary periods. SETTING: Instituto de Nutricion y Bromatologia (CSIC),
Departamento de Nutricion y Bromatologia I (Nutricion) and Seccion Departamental
de Quimica Analitica, Universidad Complutense, Madrid, Spain. RESULTS: The
palmolein period led to an increase in TC (P < 0.001; 17.7%) and serum
apolipoprotein (Apo) B levels (P < 0.001; 18.0%). LDL-C and LDL-Apo B
concentrations were higher (P < 0.001, 4.33+/-0.94 mmol/L and P < 0.01, 1.08+/
0.20 g/L, respectively) following this period than following the oleic acid-rich
sunflower oil diet (3.56+/-0.85 mmol/L, 0.93+/-0.16g/L, respectively). No
significant differences were observed in the TC/high density lipoprotein
cholesterol (TC/HDL-C) ratio between the two dietary periods. Serum and LDL
peroxides were lower (P < 0.01, 49.5%, and P < 0.001, 69.0%, respectively) after
the palmolein diet than after the oleic acid-rich sunflower oil diet. The
palmolein diet significantly increased TC, LDL-C, Apo B, VLDL-ApoB, LDL-ApoB in
women with TC > or = 6.21 mmol/L or with TC < 6.21 mmol/L, but the increase in
Apo B, LDL-C and LDL-Apo B was greater among the women with high TC. The
palmolein diet increased HDL-C in women with high or with low TC but this rise
was on the borderline of statistical significance (P = 0.06) only in
normocholesterolemics. Serum and LDL-peroxides tended to be higher in women with
TC > 6.21 mmol/L than in women with TC < 6.21 mmol/L, but palmolein decreased
serum and LDL-peroxide in hypercholesterolemics more than in the
normocholesterolemics, resulting in serum and LDL-peroxide levels which
theoretically are more adequate. CONCLUSIONS: Though palmolein increased LDL-C
concentrations, it better protected LDL particles, mainly in women with high TC,
against peroxidation than did oleic acid-rich sunflower oil.
PMID- 9756126
TI - Plasma amino acids in anorexia nervosa.
AB - OBJECTIVE: To evaluate the amino acid profile in a group of adolescents with
anorexia nervosa, and to apply alternative ways of presenting and assessing
results, so as to increase the information available for understanding the
metabolic abnormalities developed in these patients. DESIGN: Plasma amino acid
concentrations of a random group of patients with anorexia nervosa compared with
values obtained from a 'healthy' adolescent population. SETTING: The study was
performed at the tertiary children's Hospital Sant Joan de Deu. SUBJECTS: Female
adolescents (n = 92, age: 15+/-1.8 y) at diagnosis of anorexia nervosa. Reference
values for amino acids were obtained from apparently healthy adolescents (by
history and analytical data) who underwent presurgical analysis for minor
operations. INTERVENTIONS: Plasma amino acid concentrations were measured by ion
exchange chromatography. Basic laboratory analysis, carnitine and IGF-I were also
determined. RESULTS: In anorexic patients plasma concentrations of taurine,
asparagine, glutamine, glycine, methionine, phenylalanine, ornithine, and
histidine were significantly higher than reference values (Mann-Whitney, P < 0.01
0.0001), whereas arginine and cystine were lower than our reference values (P <
0.0001). Relative amino acid values (the molar fraction of the patient medians
relative to control medians) were plotted. The ratios of some amino acids were
significantly greater than those obtained from the reference population: Phe/Tyr
(P < 0.001), Met/Cys (P < 0.0001), and Gly/Val (P < 0.01). CONCLUSIONS: A trend
to hyperaminoacidemia is a common feature in anorexia nervosa. Although absolute
amino acid values cannot play a significant role in the assessment of nutritional
status in this condition, the calculation of some ratios (Phe/Tyr, Met/Cys and
Gly/Val) and the graphical representation of relative values may be useful. The
plasma amino acid profile in anorexia nervosa is different from those of other
severe malnutrition states, showing a marasmic pattern of balanced protein-energy
undernutrition. Cystine and arginine may be considered limiting amino acids in
this disease, and the consequences of their deficient concentrations for
oxidative damage should be further evaluated.
PMID- 9756127
TI - Peripheral body fat has a protective role on bone mineral density in elderly
women.
AB - OBJECTIVES: To determine whether bone mineral density is lower in women living in
homes for the elderly as compared to free dwelling control subjects, and to
investigate factors affecting possible differences. This is the first study with
this objective as the primary aim. DESIGN: Case-control study. SUBJECTS AND
METHODS: Institutionalised independent elderly women (n = 22, mean age = 75.1 y+/
6.43 s.d.) randomly selected in a home for the elderly and 22 age-matched control
women randomly selected from a sample representative of the independent non
institutionalised local population who underwent dual energy X-ray absorptiometry
(DXA) at the lumbar spine and right femoral neck; anthropometric measurements
(height, weight, subscapular and triceps skinfold thickness); general
questionnaire. RESULTS: Mean bone mineral density at the femoral neck was 0.618
g/cm2 (+/-0.130s.d.) in institutionalised women and 0.709 g/cm2 (+/-0.106 s.d.)
in controls (P = 0.02, t-test). Controlling for confounding factors in the
analysis of covariance, triceps skinfold thickness and living in a home for the
elderly turned out to be significant determinants of bone mineral density.
CONCLUSION: When compared to free dwelling control subjects, institutionalised
women show lower bone density, that is the main risk factor for fracture. Reduced
peripheral body fat was significantly associated with the low bone mineral
density observed. Health programs aimed at decreasing the incidence of fractures
among institutionalised subjects will also have to consider the effect of
nutritional or life style factors that reduce peripheral body fat.
PMID- 9756128
TI - Paper by Doucet, Almeras, White, Despres, Bouchard and Tremblay: Dietary fat
composition and human adiposity, Eur J Clin Nutr (1998); 52: 2-6.
PMID- 9756130
TI - IL-6 functions in cynomolgus monkeys blocked by a humanized antibody to human IL
6 receptor.
AB - A humanized antibody to the human interleukin-6 receptor (IL-6R), hPM-1, blocked
the interleukin-6 (IL-6) functions in normal cynomolgus monkey lymphocytes in
vitro. The binding activity of hPM-1 to non-human primate IL-6R was examined in
peripheral blood lymphocytes by flow cytometry. PM-1 recognized the IL-6R on T
lymphocytes of cynomolgus and rhesus monkeys, but did not on those of marmosets.
The homology between human IL-6R and its cynomolgus monkey counterpart was 97.3%
in the extracellular domain of the amino acid sequence, as determined by DNA
sequencing of the PCR product from peripheral blood mononuclear cells. PM-1
inhibited two functional parameters in vitro in cynomolgus monkeys: (1), T-cell
proliferation stimulated by phytohemaglutinin and human IL-6; (2), Immunoglobulin
G-production evoked by Staphylococcus aureus Cowan-1- and human IL-6-stimulated B
lymphocytes. These data show that hPM-1 binds to and functionally blocks the
cynomolgus monkey IL-6 receptors.
PMID- 9756129
TI - Erratic behavior of nitric oxide within the immune system: illustrative review of
conflicting data and their immunopharmacological aspects.
AB - The literature data assembled in this article document the variation of
immunobiological effects of nitric oxide (NO). A number of factors are obviously
responsible for the diversity, ranging from inactivity, alleviation, but not
rarely to exacerbation of certain pathogenetic processes. A better understanding
of NO interactions with the immune system can only be reached if more complex
experimental designs to study the effects of reactive nitrogen species are
adopted in the future. They should integrate major participating variables and
take into account pharmacodynamic/kinetic aspects of NO production in triggering
the ultimate effects. If manipulation of NO in the organism by means of recently
developed NO inhibitors and NO donors is to become a rational tool of
immunopharmacological strategies, detailed knowledge of their pharmacologies and
toxicologies is urgently needed in order to differentiate between the effects of
NO and other side effects. Hopefully, this approach could improve the
predictability of the clinical outcomes of NO manipulation.
PMID- 9756131
TI - Stimulation of macrophages by Bacillus firmus: production of nitric oxide and
cytokines.
AB - Immunostimulatory properties of gram-positive Bacillus firmus were investigated
under in vitro conditions using murine peritoneal macrophages. B. firmus
stimulated in a concentration and time dependent manner the secretion of tumour
necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10), but it had no
influence upon interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) production.
It also substantially augmented production of nitric oxide (NO) induced by
exogenous IFN-gamma. Inhibitory experiments using neutralizing antibodies against
TNF-alpha and/or IL-10 have demonstrated that these cytokines are responsible for
triggering the underlying mechanism(s) leading to enhanced NO production. The
cytokine-stimulatory and NO-costimulatory properties could participate in the
antiinfectious and anticancer effects of B. firmus, detected previously in the in
vivo experiments.
PMID- 9756132
TI - The pharmacokinetics and metabolism of 14C/13C-labeled ortho-phenylphenol
formation following dermal application to human volunteers.
AB - 1. The pharmacokinetics and metabolism of uniformly labeled 14C/13C-ortho
phenylphenol (OPP) were followed in six human male volunteers given a single 8 h
dermal dose of 6 microg OPP/kg body weight formulated as a 0.4% (w/v) solution in
isopropyl alcohol. The application site was covered with a non-occlusive dome
allowing free movement of air, but preventing the loss of radioactivity due to
physical contact. At 8 h post-exposure the non-occlusive dome was removed, the
dose site was wiped with isopropyl alcohol containing swabs and the skin surface
repeatedly stripped with tape. Blood specimens, urine, and feces were collected
from each volunteer over a 5 day post-exposure period and were analyzed for
radioactivity and metabolites (urine only). 2. Following dermal application, peak
plasma levels of radioactivity were obtained within 4 h post-exposure and rapidly
declined with virtually all of the absorbed dose rapidly excreted into the urine
within 24 h post-exposure. A one-compartment pharmacokinetic model was used to
describe the time-course of OPP absorption and clearance in male human
volunteers. Approximately 43% of the dermally applied dose was absorbed through
the skin with an average absorption half-life of 10 h. Once absorbed the renal
clearance of OPP was rapid with an average half-life of 0.8 h. The rate limiting
step for renal clearance was the relatively slower rate of dermal absorption;
therefore the pharmacokinetics of OPP in humans was described by a 'flip-flop'
single compartment model. Overall, the pharmacokinetics were similar between
individuals, and the model parameters were in excellent agreement with the
experimental data. 3. Approximately 73% of the total urinary radioactivity was
accounted for as free OPP, OPP-sulfate and OPP-glucuronide conjugates. The
sulfate conjugate was the major metabolite (approximately 69%). Therefore, total
urinary OPP equivalents (acid-labile conjugates+free OPP) can be used to estimate
the systemically absorbed dose of OPP. 4. The rapid excretion of OPP and
metabolites into the urine following dermal exposure indicates that OPP is
unlikely to accumulate in humans upon repeated exposure. Based on these data,
blood and/or urinary OPP concentration (acid-labile conjugates) could be utilized
to quantify the amount of OPP absorbed by humans under actual use conditions.
PMID- 9756133
TI - Medicinal herb, Thonningia sanguinea protects against aflatoxin B1 acute
hepatotoxicity in Fischer 344 rats.
AB - 1. Thonningia sanguinea, a plant used prophylactically against bronchial asthma
in Ghana was recently found to have antioxidative and hepatoprotective actions in
our laboratory. 2. In this study, the effect of T. sanguinea extract on certain
biochemical indices in serum and liver of Fischer 344 rats given a single
intraperitoneal (i.p.) dose (1 mg/kg) of aflatoxin B1 (AFB1) was investigated. 3.
Administration of AFB1 resulted in significant increases in serum alanine
aminotransferase (ALT) and glutathione S-transferase (GST) levels and a
significant decrease in aniline hydroxylase activity in liver microsomes. When T.
sanguinea (5 ml/kg) was intraperitoneally administered to rats 12 h and 1 h
before AFB1, liver injury was significantly reduced as seen in the decreased
levels of serum ALT and serum GST. However, the decrease in aniline hydroxylase
activity by AFB1 was not recovered but enhanced by T. sanguinea pre-treatment. 4.
Kinetic analysis of cytochrome P450 activity of rat liver microsomes in vitro
demonstrated that T. sanguinea inhibited aniline hydroxylase non-competitively
suggesting depression of biotransformation of AFB1 to toxic metabolites. 5. The
data indicate a hepatoprotective action of T. sanguinea against AFB1-induced
liver injury.
PMID- 9756135
TI - Implications of the hormesis hypothesis for risk perception and communication.
PMID- 9756134
TI - Effect of single neonatal vitamin D3 treatment (hormonal imprinting) on the bone
mineralization of adult non-treated and dexamethasone treated rats.
AB - Hormonal imprinting (the first encounter between the hormone and receptor after
birth) is needed for the normal development of receptor. Presence of the
appropriate hormone in excess, or its absence, as well as presence of hormone
like molecules able to bind to the maturing receptor in this time, can cause
faulty imprinting. In this experiment the effect of neonatal treatment with a
single dose of 0.05 mg cholecalciferol (vitamin D3) was studied by bone
densitometry. The treatment caused significant decrease of body weight in 3-month
old females and also significant reduction of bone mineral density (BMD) and bone
mineral content (BMC) in males. Dexamethasone treatment of 3-month old rats for
10 days increased BMD in males and BMC in females without affecting body weight.
The double treatment (vitamin D neonatally and dexamethasone when adult)
decreased the body weight of both sexes and increased BMD in males, and BMC,
BMD/bw and BMC/bw in both sexes, related to the control or the only vitamin D
treated groups. Considering the hormonal imprinting effect of neonatal vitamin D
treatment at glucocorticoid receptorial level in other experiments, similar
effects also can be supposed for vitamin D itself, manifested in the changes of
bone mineralization.
PMID- 9756136
TI - If hormesis exists...: implications for risk perception and communication.
PMID- 9756137
TI - Regulatory implications of hormesis.
PMID- 9756138
TI - Hormesis as a default parameter in RfD derivation.
PMID- 9756139
TI - Molecular analyses of adaptive survival responses (ASRs): role of ASRs in
radiotherapy.
AB - Adaptive survival responses (ASRs), whereby cells demonstrate a survival
advantage when exposed to very low doses of ionizing radiation (IR) 4 - 24 h
prior to a high dose challenge, were first reported over 15 years ago. These
responses were linked to hormesis, which implied that exposure to low levels of
IR may be beneficial to the cell. We postulate that increased survival does not
necessarily mean that the treatment is beneficial. Studies at the molecular level
indicate that ASRs are the result of misregulated cell cycle checkpoint
responses, occurring in the G1 phase of the cell cycle after IR. Specific gene
products (i.e., PCNA, cyclin D1, cyclin A, XIP8, xip5 and xip13) appear to
control these cell cycle checkpoint responses. Certain neoplastic cells show
potent ASRs because they bypass checkpoints which would otherwise lead to
apoptosis or other forms of cell death (possibly necrosis), and/or these cancer
cells lack genetic factors, such as specific caspases (cysteine aspartate
specific proteases), that control apoptosis. Alterations in these cell cycle
checkpoints or apoptotic responses may also occur during IR-induced stress
responses in normal cells, at critical times (10-18 days posttreatment) following
IR. One IR-induced protein, XIP8, may be a critical controlling factor at this
point where delayed-onset apoptosis occurs. Additionally, we have shown that the
presence or absence (i.e., SCID cells) of nonhomologous DNA double strand break
repair did not seem to influence ASRs, suggesting that ASRs may be caused by
signal transduction stress responses. ASRs may be beneficial to survival,
however, the consequence(s) of that survival may be dire. For example, many
neoplastic cells exhibited far greater ASRs than normal cells. Additionally, ASRs
were induced by as little as 1 cGy and and were enhanced by repeated exposures of
low level radiation. The implications for radiotherapy are that when a patient
arrives for port film imaging during the course of therapy, the dose-rate,
overall level of exposure, and time between port film exposure and high dose IR
treatment become potentially important factors for improved efficacy of treatment
of certain cancers. Further research is warranted to determine what molecular
factors are most important for ASRs, and current work is focusing on XIP8.
PMID- 9756140
TI - Hormesis--implications for risk assessment caloric intake (body weight) as an
exemplar.
AB - Hormesis can be considered as a parameter which has a non-monotonic relationship
with some endpoint. Since caloric intake is such a parameter, and the impact of
this parameter on risk assessment has been fairly well characterized, it can
provide clues as to how to integrate the information from a hormetic parameter
into risk assessments for toxicants. Based on the work with caloric intake, one
could: (a) define a biomarker for hormetic effect; (b) integrate specific
information on when in the animals lifespan the parameter is active to influence
parameters such as survival; (c) evaluate component effects of the overall
hormetic response; and (d) address the consequences of a non-monotonic
relationship between the hormetic parameter and endpoints critical for risk
assessment. These impacts on risk assessments have been characterized for chronic
tests, but are also true for short-term tests. A priority is the characterization
of the dose-response curves for hormetic parameters. This quantification will be
critical in utilizing them in risk assessment. With this information, one could
better quantitatively address the changes one expects to result from the hormetic
parameter, and limit the uncertainty and variability which occurs in toxicity
testing.
PMID- 9756141
TI - Risk assessment and risk management implications of hormesis.
PMID- 9756142
TI - Risk management for plausibly hormetic environmental carcinogens: the case of
radon.
AB - Risk management typically involves efforts to reduce human exposures by
establishing regulations that limit the concentration of the substance in
environmental media. In cases where a substance is widely used in commerce or is
naturally occurring in the environment, compliance costs can be substantial
because of nationwide requirements to add expensive control technologies.
Uncertainties in a dose-response function further impact risk management
decisions because they may correspond to large differences in health benefit per
unit exposure reduction. These problems are highlighted in the case of plausibly
hormetic environmental carcinogens, for which a linear-no-threshold (LNT) dose
response model has been the traditional regulatory default assumption. In this
case, model uncertainty is pivotal, and risk management is consequently
inherently controversial. However, marginal cost functions that arise for
plausibly hormetic carcinogens are expected to possess a common analytic feature
that may be particularly useful for this type of risk management problem.
Specifically, marginal cost functions in this context are expected to have roots
reflecting contaminant concentration values above which regulatory goals may be
optimally placed subject to cost constraints. Here we illustrate this heuristic
feature in the case of residential radon, using both a LNT model and a
biologically plausible hormetic model to predict associated risks of lung cancer
mortality.
PMID- 9756143
TI - Parkinson's disease: neurodegenerative mechanisms and neuroprotective
interventions--report of a workshop.
PMID- 9756144
TI - N-0923, a novel soluble dopamine D2 agonist in the treatment of parkinsonism.
AB - N-0923, a novel aminotetralin dopamine D2 agonist, was shown to effectively
reverse parkinsonian symptoms in nine dopa/agonist-responsive Parkinson's disease
patients. The drug was given up to 4.5 hours by continuous intravenous (i.v.)
infusion using an i.v. pump. The onset of anti-parkinsonian effect was seen
within minutes of the initiation of the infusion and was absent within 90 minutes
of cessation of the infusion. The short elimination half-life of N-0923 (90 min)
would allow for the rapid initiation of drug effect when necessary and at the
same time permit the effect to be terminated quickly if necessary. The drug would
be useful in situations where oral medication is not feasible or is associated
with erratic absorption. The patients tolerated the drug well. Dose escalation
load was limited by nausea and vomiting. It should be noted that the doses were
increased until these symptoms occurred, but therapeutic effects were noted well
before the side effects occurred. Using a modified Columbia scale, maximum
improvement consisted of a 27-95% drop in score. Maximum response was obtained at
infusion rates varying from 2-16 microg/kg per hour and at blood levels of 0.11
1.49 microg/mL.
PMID- 9756145
TI - Pallidotomy improves motor responses and widens the levodopa therapeutic window
in Parkinson's disease.
AB - Stereotactic posteroventral pallidotomy (PVP) as a treatment for Parkinson's
disease (PD) symptoms has been increasingly used in moderate-advanced disease. We
examined the pharmacodynamic responses of PD patients to single oral levodopa
doses and intravenous levodopa infusions before and after PVP surgery. Nine
subjects with advanced PD received a single oral dose and ramped intravenous
levodopa infusions before and 3-5 weeks after unilateral PVP. Timed motor tasks,
Unified Parkinson's Disease Rating Scale (UPDRS) evaluations, and ordinal
dyskinesia rating were performed after oral levodopa and during i.v. levodopa
infusions. Serum prolactin and dopa levels were measured during the levodopa
infusions. Overall timed motor but not motor UPDRS scores were improved after PVP
in both the worst ("off") and best ("on") states. Contralateral but not
ipsilateral limb dyskinesias were substantially reduced at all serum (dopa)
levels after PVP. Ipsilateral and contralateral timed motor performance at low
serum (dopa) levels was improved by PVP. Walking speeds at all serum (dopa)
levels were not changed by PVP. Serum prolactin was reduced equally by increasing
(dopa) preoperatively and postoperatively. PVP significantly and favorably
altered oral and intravenous levodopa pharmacodynamics by improving bilateral
limb motor function and contralateral dyskinesia but did not alter walking speed.
PVP appears to widen significantly the therapeutic window for levodopa in PD.
PMID- 9756146
TI - A double-blind, placebo-controlled study of intranasal apomorphine spray as a
rescue agent for off-states in Parkinson's disease.
AB - Nine patients with advanced levodopa-responsive Parkinson's disease were enrolled
in a double-blind, placebo-controlled crossover trial of intranasal apomorphine
as rescue therapy for parkinsonian off-states. Patients were assigned in random
order to each of four possible combinations of apomorphine, trimethobenzamide
antiemetic, and their matched placebos and received detailed in-office motor
scoring during each of the four study periods. Patients also completed diaries
describing the effectiveness of the nasal spray for reversing off-states. A
statistically significant reduction in the Unified Parkinson's Disease Rating
Scale (UPDRS) motor score was seen following active apomorphine during in-office
evaluation visits but not following placebo nasal spray. Patient diaries revealed
that active apomorphine had a latency to onset of 11 minutes and a duration of 50
minutes. Significant nausea from apomorphine spray was seen in only one patient
whereas nasal irritation was disabling in three and mild in two. We conclude that
intranasal apomorphine is an effective rescue agent for parkinsonian off-states
although nasal irritation is a limiting factor.
PMID- 9756147
TI - Dopamine D3 receptor is decreased and D2 receptor is elevated in the striatum of
Parkinson's disease.
AB - The mesolimbic dopamine (DA) system preferentially innervates the D3 receptor,
whereas the D2 receptor is, in addition, a target of the nigrostriatal DA system.
In human brain D3 receptors and D3 mRNA-expressing neurons are largely segregated
to brain regions that are the targets of the mesolimbic DA system and the
efferents of the "limbic striatum." Thus, D3 receptors may regulate effects of DA
on the "limbic" cortico-striatal-pallidal-thalamic-cortical loop. The
nigrostriatal DA system is considerably more damaged in Parkinson's disease (PD)
than the mesolimbic DA system. We report here, using radioligands selective for
the D2 and D3 receptor, that these receptors are independently changed in PD.
Tissue collected at autopsy from nine subjects with a diagnosis of PD and eight
age-matched subjects with no evidence of a neurologic disorder was processed for
[125I]epidepride binding to D2 receptors, [125I] trans-7-OH-PIPAT binding to D3
receptors, [125I]RTI-55 for the DA transporter (DAT), and immunoautoradiography
for tyrosine hydroxylase (TH) using autoradiographic methods. Dopaminergic
innervation to the caudal putamen was profoundly reduced and to a lesser extent
in the rostral putamen in PD. DAT sites but not TH protein levels were reduced in
the nucleus accumbens (NAS) in PD compared with age-matched control subjects.
This is consistent with a loss of dopaminergic innervation from the mesolimbic DA
system but elevation in TH production. D3 receptors were significantly reduced in
PD by 40-45% particularly in the NAS and putamen. D2 receptors were elevated in
PD in the dorsal putamen by 15%. The reduction in D3 receptor number was not
observed in PD cases with a diagnosis of less than 10 years. The changes in DA D3
receptor number is interesting in light of the development of antiparkinsonian
agents that are D3-preferring agonists.
PMID- 9756148
TI - Amantadine reduces levodopa-induced dyskinesias in parkinsonian monkeys.
AB - The antidyskinetic potential of the glutamate NMDA receptor channel blocker
amantadine was evaluated in four levodopa-primed parkinsonian monkeys using two
different regimens (1.25 or 2.5 mg/kg administered subcutaneously twice daily for
3-6 days). When administered with a relatively low dose of levodopa, amantadine
produced a near-total suppression of choreiform dyskinesias and a substantial
reduction in dystonic dyskinesias at the expense of a significant reduction in
antiparkinsonian response. With a high dose of levodopa, amantadine had a smaller
but still significant effect on dyskinesias without altering the antiparkinsonian
response. These results lend support to the view that glutamate receptor-mediated
mechanisms contribute to levodopa-induced dyskinesias. They also suggest that
amantadine could alleviate such complications in parkinsonian patients,
especially with careful dose optimization.
PMID- 9756149
TI - Clinical characteristics of essential tremor: data from a community-based study.
AB - BACKGROUND: 99.5% of individuals with essential tremor (ET) who live in the
community have mild tremor and do not attend clinics. Clinic-based studies of ET
have not allowed investigators to characterize the full clinical spectrum of this
disorder. In community-based studies of ET, the primary focus has been the
prevalence rather than the clinical characteristics of ET. OBJECTIVE: To describe
the clinical characteristics of ET as seen in a community-based study. METHODS:
73 subjects with ET, identified in a community-based study of ET in Washington
Heights-Inwood, New York, underwent a standardized 84-item physician-administered
tremor interview and a 26-item videotaped tremor examination which included 12
bedside tests for ET. Two neurologists who specialized in movement disorders and
who demonstrated excellent interrater agreement rated the severity of tremor
using a 0 to +3 clinical rating scale and assigned a total tremor score (range, 0
36) and a diagnosis of ET. RESULTS: Diagnoses in the 73 cases were: definite ET
(18, 24.7%), probable ET (32, 43.8%), and possible ET (23, 31.5%). The mean total
tremor score was 17.8 of 36. Thirty-six of 73 (49.3%) were asymptomatic,
answering "no" to the question "do you often have shaking or tremor that you
can't control?" Sixty-seven of 73 (91.8%) had not been prescribed medication for
tremor. On average, subjects received tremor ratings of > or =+2 on only 5.4 of
the 12 bedside tests for ET. Kinetic tremor was rated as more severe than
postural tremor in 72 (98.6%) of 73 cases. CONCLUSIONS: We present the clinical
findings of a group of largely untreated, unselected cases of ET that would not
otherwise have come to neurologic attention. The tremor was mild, often
asymptomatic, and not uniformly present throughout the examination. It was rarely
treated. The kinetic component of the tremor was more severe than the postural
component. These clinical data further our understanding of the clinical spectrum
of ET.
PMID- 9756150
TI - Sternomastoid function during hemispheric suppression by amytal: insights into
the inputs to the spinal accessory nerve nucleus.
AB - The debate as to whether the sternomastoids receive ipsilateral, contralateral,
or bilateral cortical innervation is based largely on the observation of stroke
patients and, to a lesser extent, on animal experimentation. The variability of
vascular lesions, the lack of pathology correlation in the early reports, and the
differences in posture between humans and laboratory animals contributed to the
controversy. We studied the function of the sternomastoid (SM) muscles during
transient, complete left hemiplegia in 18 right-handed patients undergoing a Wada
test. After injection in the right internal carotid artery (ICA), 14 patients
were able to lift and turn their heads both to the right and to the left on
command. Ten of the 14 patients who were able to follow commands after the
injection had weakness of the right sternomastoid compared with the left. Our
findings demonstrate that the left hemisphere can activate both the right and the
left sternomastoid muscles during suppression of the right hemisphere. The
sternomastoids receive bilateral hemispheric innervation and the maximal input
comes from the ipsilateral hemisphere.
PMID- 9756151
TI - Brain phospholipids and fatty acids in Friedreich's ataxia and spinocerebellar
atrophy type-1.
AB - Previous studies of patients with spinocerebellar atrophy type 1 (SCA-1) and
Friedreich's ataxia (FA) have suggested the occurrence of membrane disturbances
in both disorders. We measured concentrations of phosphatidylcholine (PC), diacyl
and plasmalogen phosphatidylethanolamine (PE), and phosphatidylserine (PS), along
with their fatty acid profiles, in the brains of eight patients with Friedreich's
ataxia (FA) and nine patients with dominantly inherited spinocerebellar atrophy
type 1 (SCA-1). Compared with the controls, levels of all phospholipid types (PE,
PS, and PC) were reduced in the cerebellar but not occipital cortex of SCA-1
patients. In contrast, in the FA group, levels of PS and PE, but not PC, were
reduced in both cerebellar and occipital cortices. The fatty acid composition of
individual brain phospholipids was altered in both FA and SCA-1 patients, most
markedly in the plasmalogen PE and PS classes of cerebellar phospholipids. Given
the neuropathologic characteristics of each disorder, it is likely that altered
fatty acid composition and phospholipid levels in SCA-1 cerebellar cortex occur
as a consequence of pronounced cerebellar degeneration. In contrast, reduced
phospholipid levels in FA cerebellar and occipital cortex, areas characterized
by, at most, minimal neuronal loss in FA, may represent a widespread alteration
in cellular phospholipid metabolism occurring in response to the specific gene
defect in the disorder.
PMID- 9756152
TI - Polysomnographic sleep measures in patients with uremic and idiopathic restless
legs syndrome.
AB - In the present study, the nocturnal electroencephalographic sleep pattern, the
number of periodic leg movements (PLM) during sleep and wakefulness, and the
subjective sleep parameters of patients with uremic (n = 10) and idiopathic (n =
17) restless legs syndrome (RLS) were compared. The main finding was that the
total number of PLM (p = 0.019), the PLM index (p = 0.018), and the PLM index
while awake (p = 0.003) were significantly higher in patients with uremic RLS
compared with patients who had idiopathic RLS. Additionally, both groups showed a
distinct time-of-night pattern of PLM activity. Polysomnographic measures of
sleep continuity (total sleep time, sleep efficiency, sleep onset latency, time
awake) and sleep architecture (amount of nonrapid eye movement sleep stages 1, 2,
3, and 4 and the amount of rapid eye movement sleep) did not differ between
uremic and idiopathic RLS patients. With regard to subjective parameters, sleep
quality was estimated to be worse in uremic RLS (p = 0.033), whereas other
parameters (for example, severity of RLS, quality of life) did not differ between
the two groups. It is suggested that uremia itself worsens the motor symptoms of
RLS, probably as a result of increased excitability.
PMID- 9756153
TI - Adult head-banging and stereotypic movement disorders.
AB - Stereotypic movement disorders (SMD) such as head-banging, which are common among
children with mental retardation or pervasive developmental disorders, may also
occur in intellectually normal adults. We report a 27-year history of daily head
banging with self-injury in a 49-year-old man with normal cognition. The patient
had no personal or family history of Tourette's syndrome, tic disorder, obsessive
compulsive disorder (OCD), or mental retardation. The frequency of his
stereotypical head-banging increased with anxiety, loud noises with startle, and
boredom. He reported a sense of pleasure from his head-banging, and the frequency
of this behavior decreased when he was treated with the opioid antagonist
naltrexone. Although not diagnostic, the self-stimulatory or pleasurable
component of head-banging, body-rocking, thumb-sucking, and other SMD may help
distinguish them from tics, Tourette's syndrome, OCD, and deliberate self-harming
behavior. This report reviews the disorders associated with SMD and discusses the
potential mechanisms for these behaviors. The treatment of SMD includes drugs
that work through opioid, serotonergic, or dopaminergic systems.
PMID- 9756154
TI - Effective treatment of orthostatic tremor with gabapentin.
AB - We report seven patients with orthostatic tremor (OT) who were successfully
treated with the anticonvulsant gabapentin. Five of the patients had been
previously tried on clonazepam, the most commonly used drug for OT, four without
any benefit. The degree of improvement perceived by the patients with gabapentin
varied from 60-80% (mean 73%). The effective dose of gabapentin ranged from 300
1800 mg/day (mean 1030 mg/day). The side effects were generally mild, transient,
and dose-related. Duration of response has so far ranged from 2-22 months (mean
11 months) with all patients still currently benefiting from gabapentin. We
conclude that gabapentin may be an effective treatment for OT. Further trials are
indicated.
PMID- 9756155
TI - Disordered locomotion in the AS/AGU mutant rat and the effects of L-dopa or fetal
midbrain grafts.
PMID- 9756156
TI - An akinetic-rigid syndrome, depression, and stereotypies in a young man.
AB - A young man is presented who developed an akinetic-rigid syndrome shortly after a
minor illness. Rituals and stereoptypies were prominent. At its most severe he
was unable to feed himself. There was no response to L-dopa/cardopa treatment. A
course of ECT was followed by a marked improvement in his condition. Attempts to
stop ECT for more than a week have led to recurrence of his bradykinesia.
PMID- 9756157
TI - Treatment of hereditary trembling chin with botulinum toxin.
PMID- 9756158
TI - A case of tardive tremor successfully treated with clozapine.
PMID- 9756159
TI - Theophylline-induced stuttering.
PMID- 9756160
TI - Complex movement disorder associated with fluvoxamine.
PMID- 9756161
TI - New use for an old drug: amantadine benefits levodopa-induced dyskinesia.
PMID- 9756162
TI - P450 enzymes and Parkinson's disease.
PMID- 9756163
TI - Intranuclear neuronal inclusions in DRPLA.
PMID- 9756164
TI - Cerebral hypoperfusion and hypometabolism in chorea-acanthocytosis.
PMID- 9756166
TI - Modelling the enhancement of fractionated radiotherapy by gene transfer to
sensitize tumour cells to radiation.
AB - BACKGROUND AND PURPOSE: Several strategies now exist for the use of gene transfer
methodologies to sensitize tumour cells to radiation. These include the
transfection of genes synthesizing cytokines, p53 gene replacement and methods
based on the use of HSV-tk and gancyclovir. Very recently, the sequencing of
radioprotector or repair genes, such as ATM, Ku80 and XRCC2, has made it possible
to consider the design of gene transfer strategies resulting in protector gene
knock-out. Selectivity of transfected gene expression might be achieved by use of
tissue-specific promoters or by the trophism of viral vectors. The purpose of
this study was to evaluate the probable efficacy of such strategies. METHODS: We
have modelled gene transfer-mediated radiosensitization of tumour cells during
radiotherapy, focusing on anti-protector gene strategies, to explore the role of
transfection frequency, sensitizing efficacy, transfection stability,
untransfectable subpopulations, the timing of gene therapy and the treatment
schedule structure. RESULTS: We predict a substantial therapeutic benefit of gene
transfer treatment (with at least weekly transfection) which modifies cellular
radiosensitivity by a factor of 1.5 or more, despite modest efficiency of
cellular transfection (e.g. 50%), transient retention of the transfected gene
(e.g. 2-day half-life) and the existence of a small minority (e.g. 1%) of
untransfectable cells. CONCLUSIONS: The analysis shows repeated administration of
gene transfer treatment to be obligatory and implies that the existence of
untransfectable minority subpopulations (i.e. cells inaccessible to the vector)
will be the major limiting factor in therapy. Experimental work is needed to
confirm these predictions before clinical studies begin.
PMID- 9756165
TI - Hyperthermic isolated limb perfusion with tumour necrosis factor and melphalan as
treatment of locally advanced or recurrent soft tissue sarcomas of the
extremities.
AB - Hyperthermic isolated limb perfusion (HILP) with various chemotherapeutic agents
has been used for the local treatment of high-grade soft tissue sarcomas (STS) of
the extremities, but in most cases with a disappointing result. Most regimens
should certainly not be considered superior to surgery plus radiotherapy.
Although the majority of extremity STS can be resected locally, some have a very
large size and are in close proximity to bones, nerves or blood vessels. In these
cases, amputation is the only means of resecting the tumour. A new combination of
drugs used in the set-up of HILP with tumour necrosis factor-alpha and melphalan
has emerged as a very promising option for the limb-saving management of locally
advanced STS. In recent studies, complete response rates of approximately 30% and
partial remission rates of 50% have been achieved, while the overall limb-salvage
rate is more than 80%.
PMID- 9756167
TI - Radical radiotherapy for carcinoma of the oesophagus: an effective alternative to
surgery.
AB - BACKGROUND AND PURPOSE: Despite advances in operative and postoperative care,
long term survival rates following radical oesophagectomy are poor. Surgery
remains the mainstay of radical treatment despite various series reporting
similar results for treatment with radiotherapy, in particular in the upper third
of the oesophagus. We have studied a cohort of patients treated with definitive
radiotherapy to examine the influence on survival of changes in diagnostic
scanning and radiotherapy computer planning as well as various patient and
disease related prognostic factors. PATIENTS AND METHODS: From 1985 to 1994, 101
patients with clinically localised carcinoma of the oesophagus were treated at
the Christie Hospital with definitive radiotherapy. This included 11 patients
with oesophageal adenocarcinoma. Diagnostic and planning techniques changed over
the period studied, with increasing use of both diagnostic and radiotherapy
planning CT scanning. Radiotherapy doses ranged from 45 to 52.5 Gy in 15 or 16
fractions over 3 weeks. RESULTS: The 3- and 5-year survival figures were 27% and
21%, respectively, corrected for intercurrent deaths. Survival was better for
adenocarcinoma than squamous cell carcinoma, though not statistically
significantly. The only significant prognostic factor (P = 0.01) was the use of
diagnostic CT scanning (42% versus 13% 5-year survival with or without diagnostic
CT scanning, respectively) which was associated with an increase in field size.
Radiotherapy was well tolerated with no acute mortality or significant morbidity.
Late stenosis requiring oesophageal was seen in five of 20 patients surviving 3
years or more. CONCLUSIONS: Survival following well planned radiotherapy is an
effective alternative to surgery for both squamous cell and adenocarcinoma.
Advances in staging and three-dimensional planning and the use of multimodality
treatment may further improve survival.
PMID- 9756168
TI - Haematological toxicity of cranio-spinal irradiation.
AB - BACKGROUND: To assess the frequency and severity of myelosuppression due to
cranio-spinal irradiation either alone or in combination with chemotherapy and to
identify patients at high risk of haematological toxicity who may require
supportive therapy. MATERIALS AND METHODS: Between 1965 and 1994, 210 patients
received cranio-spinal axis (CSA) radiotherapy as a component of treatment for
primary CNS tumours at the Royal Marsden Hospital. Full blood counts (FBC) were
obtained before, during and after radiotherapy in 200 patients. Haematological
toxicity was graded according to the WHO criteria and duration was measured from
the onset of grades 3 and 4 toxicity until recovery to grade 2. RESULTS: Sixty
six (33%) patients developed grades 3 and 4 haematological toxicity. Nadir
occurred during radiotherapy and was most frequent during the second week of
spinal radiotherapy. Low haemoglobin and white cell counts prior to radiotherapy
increased the likelihood of myelosuppression. Nine patients had febrile episodes
requiring antibiotic therapy. Treatment was interrupted in 49 patients but
treatment time was extended beyond 12 weeks in only 17 (8%) patients of which
nine were due to haematological toxicity. Chemotherapy (vincristine) during
radiotherapy did not impact on haematological toxicity. Age and prior
chemotherapy were independent predictive factors for haematological toxicity. The
relative risk of leukopaenia in children compared to adults was 7.9 (95% CI 3.4
18.6%). Patients who received prior chemotherapy had a relative risk of toxicity
of 6.1 (95% CI 2.9-12.8%). CONCLUSION: One-third of patients undergoing CSA
radiotherapy develop grades 3 and 4 haematological toxicity. The risk is higher
in children and in patients who receive chemotherapy prior to radiation. There
was no treatment-related mortality and only nine of 200 patients (9/60 of those
with toxicity) required supportive treatment for neutropaenic sepsis. The low
incidence severe haematological toxicity does not warrant routine use of
haemopoietic growth factors during CSA irradiation and future studies should
target high risk subgroups.
PMID- 9756169
TI - Reduced incidence of the somnolence syndrome after prophylactic cranial
irradiation in children with acute lymphoblastic leukemia.
AB - A prospective double blind randomized trial comparing two different dose
schedules of continuous steroid coverage during prophylactic cranial radiotherapy
(CRT) in leukemic children was conducted to find out the optimum dose to be
prescribed to reduce the incidence of Somnolence Syndrome (SS). Between April
1994 and February 1996, 32 patients with acute lymphoblastic leukemia received
CRT of 18 Gy in 10 fractions. Patients were randomized to receive oral
dexamethasone of 2 or 4 mg/m2 during radiotherapy. The diagnosis of SS was made
clinically based on symptoms of somnolence. All patients were followed for a
minimum of 8 months. The overall incidence of SS was 40%. The development of SS
was steroid dose dependent. In low dose steroid arm the incidence of SS was 64.3%
(9/14), compared to 17.6% (3/17) in high dose arm with statistically significant
difference (P = 0.008). The median time to development of SS was 4 weeks. The
most common symptom of SS was drowsiness followed by anorexia, headache, nausea,
vomiting, decreased activity, irritability, fever and ataxia, respectively. The
duration of symptoms ranged from 2 to 14 days. The development of SS was not
related to the presence of acute reactions, age at the time of CRT and sex. In
all cases the symptoms subsided completely and spontaneously. Our results suggest
that steroid coverage at a dose of 4 mg/m2 during CRT reduces the incidence of
SS. However, a multicentric prospective randomized trial is needed to determine
the role and the optimal dose of steroid.
PMID- 9756170
TI - Dose-effect relations for early local pulmonary injury after irradiation for
malignant lymphoma and breast cancer.
AB - PURPOSE: To quantify the influence of treatment- and patient-related factors on
the severity of early local pulmonary injury and to establish whether regional
differences are present for local dose-effect relations for early radiation
induced pulmonary injury. METHODS: Forty-two patients with malignant lymphoma and
40 breast cancer patients were examined prior to and 3 months after radiotherapy.
The lymphoma patients were irradiated with mantle fields to an average dose of 38
Gy and the breast cancer patients were irradiated with internal mammary node
fields with or without tangential breast fields to an average dose of 50 Gy. Dose
effect relations for local perfusion, ventilation and density changes were
determined using correlated single photon emission computed tomography (SPECT)
and CT data. A multivariate analysis was performed to study the influence of
irradiated volume, chemotherapy (CMF and MOPP/ABV), smoking, age and gender. In
addition, dose-effect relations for different regions in the lung were
determined. RESULTS: A similar and almost linear increase of early functional
changes as a function of radiation dose was observed for perfusion and
ventilation, whereas the shape of the dose-effect relation and the magnitude of
early structural changes were different for density. For the three end-points
studied, regional differences in radiosensitivity could not be demonstrated. For
the posterior lung region compared to the anterior lung region, however, a
difference was observed, which could be attributed to a gravity-related effect in
the measuring procedure. Local structural changes (density) were significantly
smaller for smokers (P = 0.002) and young patients (P = 0.007), whereas the CMF
chemotherapy regimen given after radiotherapy (P = 0.017) significantly increased
the amount of functional changes (perfusion). The magnitude of local pulmonary
changes was independent of the irradiated volume, the MOPP/ABV chemotherapy
regimen and gender. CONCLUSION: The dose-effect relations for early radiation
induced local pulmonary changes were independent of the irradiated volume,
MOPP/ABV, gender and lung region. CMF, smoking and age influenced the magnitude
of early pulmonary changes and should be taken into account in dose-escalation
protocols.
PMID- 9756171
TI - Lethal pulmonary toxicity after autologous bone marrow transplantation/peripheral
blood stem cell transplantation for hematological malignancies.
AB - BACKGROUND AND PURPOSE: Retrospective evaluation of the incidence of lethal
pulmonary complications (LPC) with special emphasis on interstitial pneumonia
(IP) in a large group of patients homogeneously treated with hyperfractionated
total body irradiation (HTBI) before autologous bone marrow transplantation
(ABMT) or peripheral blood stem cell transplantation (PBSCT) for hematological
malignancy. The factors influencing IP are discussed. MATERIALS AND METHODS: Of
260 patients (maximum follow-up 137 months) that were treated with ABMT or PBSCT
for hematological neoplasms between 1982 and 1994, 209 patients received HTBI and
could be evaluated with respect to lethal pulmonary complications and especially
lethal interstitial pneumonia. For most patients (n = 155), the HTBI dose was
14.4 Gy (lung dose 9-9.5 Gy) given in 12 fractions over 4 days. Twenty-one
patients received a total dose of > or =15 Gy with pulmonary doses of 9-10.5 Gy.
RESULTS: The actuarial overall 5-year survival for all 209 patients evaluated was
44 +/- 4%, enabling valid evaluation with respect to lethal pulmonary toxicity.
The actuarial incidence of all LPC during the first year was calculated as being
8 +/- 2%. The actuarial incidence of lethal IP is certainly lower and was
estimated to be between 3 and 5% for all patients. The overall treatment-related
mortality was 12% in 188 patients that received a total dose of <15 Gy and 24%
among the patients treated with a total dose of > or =15 Gy. CONCLUSION:
ABMT/PBSCT, like other transplant modalities without significant graft versus
host disease (GvHD), has a low transplant-related mortality, a very small rate of
overall LPC and a low incidence of lethal IP after HTBI. Doses up to 14.4 Gy with
lung doses of 9-9.5 Gy can be administered safely. For total doses of > or =15 Gy
with lung doses of 9-10.5 Gy, the risk of serious transplant-related
complications cannot yet be finally assessed but such higher doses should be
considered with caution because of the possibility of increasing toxicity in
organs other than the lung.
PMID- 9756172
TI - Regional dose response to pulmonary irradiation using a manual method.
AB - PURPOSE: To better understand the dose dependence of radiation therapy (RT)
induced changes in regional lung perfusion and tissue density, using a manual
method to reduce inaccuracies that might be present in previously described
automated methods. MATERIALS AND METHODS: Patients who were to receive RT for
tumors in and around the thorax, wherein portions of healthy lung would be
incidentally irradiated, were prospectively studied. Changes in regional
perfusion and tissue density were assessed by comparison of pre- and post-RT
single photon emission computed tomography (SPECT), lung perfusion scans and
computed tomography (CT) scans, respectively. The three-dimensional dose
distribution was calculated on the pre-RT CT scan and correlated to the other
scans via image registration. Study volumes were defined by hand and individually
visualized on pre- and post-RT scans. The manually generated dose response data
were compared to data generated using automated methods. The relationship between
CT density and SPECT perfusion was also determined. RESULTS: Thirteen patients
with lung cancer were evaluated for changes in tissue density and 11 patients
were evaluated for changes in regional perfusion at 12 months post-RT. In
general, density increases with increasing regional dose, with marked changes at
>60 Gy. Regional perfusion decreases with increasing regional dose. In the low
dose regions, relative perfusion increases by 35% on average. Manually measured
dose responses correlated well with those determined automatically. The
relationship between regional perfusion and CT density indicates a wide range of
perfusion over a narrow range of CT density, with markedly reduced perfusion at
CT densities of > -600 and < -900 H. CONCLUSIONS: The manually generated CT
density dose response data broadly agree with data previously generated using
automated methods. The manually generated perfusion dose response data are in
fairly good agreement with automated data, lending credibility to the accuracy of
the automated methods. Regional perfusion is markedly diminished where CT density
is outside the range of normal lung tissue.
PMID- 9756174
TI - What margins should be added to the clinical target volume in radiotherapy
treatment planning for lung cancer?
AB - BACKGROUND: The planning target volume in radiotherapy treatment planning takes
into account both movements of the clinical target volume (CTV) and set-up
deviations. MATERIALS AND METHODS: A group of patients who received radiotherapy
for lung cancer were studied. In order to measure the CTV movements due to
respiration and other internal organ motions, fluoroscopy was performed for 20
patients. To study the accuracy and reproducibility of patient and beam set-up,
553 electronic portal images from 20 patients were evaluated. Discrepancies
between planned and actual field positions were measured and the systematic and
random errors were identified. The combined effect of these geometrical
variations was evaluated. RESULTS: The average CTV movement with quiet
respiration was about 2.4 mm in the medio-lateral and dorso-ventral directions.
Movement in the cranio-caudal direction was on average 3.9 mm with a range of 0
12 mm. The systematic set-up errors were on average 2.0 mm in the transversal
plane and 3.0 mm in the cranio-caudal direction. The random errors can be
described by their standard deviations of 3.2 and 2.6 mm. In this study, the
combined effect of the two parameters (CTV movement and set-up deviations) varied
between 7.5 and 10.3 mm in different anatomical directions. CONCLUSIONS: In our
daily clinical routine, we use a margin of 11 mm in the transversal plane and 15
mm cranially and caudally, also taking into account other unquantified variations
and uncertainties.
PMID- 9756173
TI - Evaluation of two dose-volume histogram reduction models for the prediction of
radiation pneumonitis.
AB - PURPOSE: To evaluate the similarities between the mean lung dose and two dose
volume histogram (DVH) reduction techniques of 3D dose distributions of the lung.
PATIENTS AND METHODS: DVHs of the lungs were calculated from 3D dose
distributions of patients treated for malignant lymphoma (44), breast cancer (42)
and lung cancer (20). With a DVH reduction technique, a DVH is summarized by the
equivalent uniform dose (EUD), a quantity which is directly related to the normal
tissue complication probability (NTCP). Two DVH reduction techniques were used.
The first was based on an empirical model proposed by Kutcher et al. (Kutcher,
G.J., Burman, C., Brewster, M.S., Goitein, M. and Mohan, R. Histogram reduction
method for calculating complication probabilities for three-dimensional treatment
planning evaluations. Int. J. Radiat. Oncol. Biol. Phys. 21: 137-146, 1991),
which needs a volume exponent n. Several values for n were tested. The second
technique was based on a radiobiological model, the parallel functional subunit
model developed by Niemierko et al. (Niemierko, A. and Goitein, M. Modeling of
normal tissue response to radiation: the critical volume model. Int. J. Radiat.
Oncol. Biol. Phys. 25: 135-145, 1993) and Jackson et al. (Jackson, A., Kutcher,
G.J. and Yorke, E.D. Probability of radiation-induced complications for normal
tissues with parallel architecture subject to non-uniform irradiation. Med. Phys.
20: 613-625, 1993), for which a local dose-effect relation needed to be
specified. This relation was obtained from an analysis of perfusion and
ventilation SPECT data. RESULTS: It can be shown analytically that the two DVH
reduction techniques are identical, if the local dose-effect relation obeys a
power-law relationship in the clinical dose range. Local dose-effect relations
based on perfusion and ventilation SPECT data can indeed be fitted with a power
law relationship in the range 0-80 Gy, from which values of n = 0.8-0.9 were
deduced. These correspond to the commonly used value of n = 0.87 for lung tissue
and yielded EUDn=0.87 values which were almost identical to the mean lung doses.
For other n values, for which no experimental data are present, differences exist
between EUD and mean dose values. Six patients with malignant lymphoma (6/44) and
none of the breast cancer patients (0/42) developed radiation pneumonitis. These
cases occurred only at high values for the mean lung dose. CONCLUSION: The two
DVH reduction techniques are identical for lung and are very similar to mean dose
calculations. The two techniques are also relatively similar for other model
parameter values.
PMID- 9756175
TI - The magnitude of treatment field set-up parameter correction in radiation
therapy.
AB - To achieve a better correction effect in radiation treatment, a correction
(c(alpha)) is suggested which is optimal in the sense of minimal standard
deviation of the residual systematic displacement (delta(r)) obtained after
correction. To evaluate the improvement due to c(alpha), the performance of the
original Bel's rule was compared to the performance of its modification, where
same decision-making thresholds were used but a correction c(alpha) was applied.
For this, 5000 treatment courses were simulated at different standard deviations
(sigma(delta) and sigma(delta)) of the systematic displacement delta and random
error delta. The experiments showed improved accuracy by up to 7% in terms of
?delta(r)? < or = 1.5 mm and also a reduced average number of corrections per
patient of about 0.1 corrections.
PMID- 9756176
TI - Quality assurance of physical parameters in radiation oncology at the University
Hospital of Basel--a retrospect.
AB - BACKGROUND AND PURPOSE: The necessity for and the benefit of a quality assurance
program in radiation oncology are not questioned. Nevertheless, a retrospective
analysis of the accumulated results of several years of quality assurance offers
the possibility for further optimization. MATERIALS AND METHODS: The results of
the physical quality control in radiation treatment planning and on radiation
treatment units in the Institute for Radiation Oncology at the University
Hospital of Basel for the years 1985, 1991 and 1994 are analyzed and compared
mutually. The frequencies of the deviations from the nominal values for the
different tests are stated. RESULTS: The relevance of the deviations for the
different parameters is rated and the manifested influence of the type and age of
the equipment on the results of the quality assurance is discussed. CONCLUSIONS:
A condition for the maximum benefit gained from the quality assurance is the
oncologist's understanding of the necessity for regular checks and the urgency
for eliminating the established deficiencies. In that way the accuracy for the
treatment planning, simulation and set-up process and for the realization of the
radiation treatment can be increased and the methods can be improved.
PMID- 9756177
TI - Treatment planning for radiotherapy in northern Italy: a survey by the National
AIFB-AIRO Committee on 3D-Treatment Planning. Italian Association for Biomedical
Physics. Italian Association for Radiation Oncology.
AB - BACKGROUND AND PURPOSE: A survey was performed in 1996 to investigate the
structures and the process of radiation therapy treatment planning in clinical
practice within northern Italy, with particular emphasis on the current and
future implementation of 3D equipment and techniques. MATERIALS AND METHODS: Of
57 existing radiation therapy (RT) centres covering a population of 25 million
people (45% of the total population of Italy) and treating over 58,000 cancer
patients (70% of the cancer cases in Italy) each year, 46 centres were deemed
eligible for the survey; a questionnaire was sent to a medical physicist working
in each eligible RT centre, 40 of whom responded, making the basis for this
report. RESULTS: A dedicated CT scanner was available in 25% of the responding
centres and a total of 49 radiation therapy planning systems (RTPS) were
reported; none of the RTPS were able to perform 3D calculations, but 50% of the
centres had an advanced 2D or 2.5D system. Connection between CT scan and RTPS
was by tape or disk in 62% of centres. Immobilization devices were used
frequently for head and neck patients (88% of centres), but not for lung (16%) or
prostate cancer (24%) patients; the number of contoured slices was largely
variable, exceeding 10 in only about 30% of the responding centres. The average
working time per patient seemed to closely reflect the number of slices used and
the number of critical organs contoured. Finally, the majority of the responding
physicists did not favour the use of more than 20 CT slices for 3D treatment
planning, nor did they forecast a general spread of this technique in the next 2
3 years. CONCLUSIONS: This survey has shown (1) a heterogeneous picture, with 20%
of centres ready to implement 3D techniques and 20% of centres lacking the
possibility of planning treatments and (2) a general difficulty in coping with
the workload represented by 3D treatment planning.
PMID- 9756178
TI - A dosimetric intercomparison of kilovoltage X-rays, megavoltage photons and
electrons in the Republic of Ireland.
AB - BACKGROUND AND PURPOSE: A comprehensive dosimetry intercomparison has been
carried out involving all the radiotherapy centres, all external beam modalities
and every radiotherapy treatment unit in the Republic of Ireland. MATERIALS AND
METHODS: Reference point measurements were made for all megavoltage photon beams.
Doses were also investigated in planned three-field distributions. One of these
was in a homogeneous epoxy resin solid water phantom, whilst the second included
a lung equivalent insert. The intercomparison was also carried out for three
electron energies in each centre. The position of the depth of maximum dose for a
standard field size was independently determined, as was the beam energy and a
subsequent beam calibration was made. In addition, a kilovoltage X-ray
intercomparison was carried out on every kilovoltage quality. RESULTS: For 13
megavoltage photon beams a mean ratio of intercomparison measured dose to locally
measured dose of 1.002 was obtained (standard deviation 1.2%). For 12 electron
beam measurements a mean ratio of intercomparison measured dose to locally
measured dose of 1.018 was obtained (standard deviation 0.8%). For four
kilovoltage beams a mean ratio of intercomparison measured dose to locally
measured dose of 0.997 was obtained (standard deviation 1.9%). CONCLUSIONS: The
intercomparison has given confidence in the basis of clinical delivery of
radiation dose in radiotherapy treatment and in the consistency (precision) of
dosimetry between different centres within the Republic of Ireland. In addition,
it has established a methodology for subsequent ongoing routine radiotherapy
dosimetry audit and a baseline set of results to act as an initial reference
point.
PMID- 9756179
TI - Consistency in quality control programmes for electron accelerators in
radiotherapy centres.
AB - BACKGROUND AND PURPOSE: To gain insight into the current practice of quality
control (QC) of medical electron accelerators and to reduce possible variations
in test frequencies and test procedures. MATERIALS AND METHODS: An extensive
questionnaire on QC procedures of medical electron accelerators was distributed
and completed by all (21) radiotherapy institutions in The Netherlands. The
questions were related to safety systems, mechanical parameters, beam profiles,
beam energy, absolute dosimetry, wedge filters, the dose monitor system and
radiation leakage. The data of the questionnaire were compared with
recommendations given in national and international reports on QC of electron
accelerators. RESULTS: Large variations in time spent on QC exist, especially for
accelerators having dual energy photon beams and several electron beam energies.
This diversity is mainly due to differences in philosophy with regard to QC and
the differences in resources and machine time available. Furthermore, large
variations in test frequencies and test methodologies were observed. The staffing
level involved in the QC measurements was evaluated and compared with recent
recommendations provided by EFOMP-ESTRO. CONCLUSIONS: From these recommendations
and the results of the questionnaire, a set of minimum guidelines for a QC
programme could be formulated and implemented in all radiotherapy institutions in
The Netherlands.
PMID- 9756180
TI - Cytokines and their receptors as therapeutic targets in asthma.
AB - Cytokines are very potent pro-inflammatory agents. Several cytokines are present
in abnormal quantities in asthmatic airway tissues. In vitro and in vivo
experiments demonstrate that these cytokines have biological effects relevant to
the pathogenesis of asthma. We review the evidence that interleukin-4 (IL-4),
interleukin-5 (IL-5), interleukin-10 (IL-10), interleukin-12 (IL-12) and
interferon-gamma (IFNgamma) have the potential of playing a key role in the
pathogenesis of asthma. Inhibition of the activity of IL-4 or IL-5 and enhancing
or mimicking the action of IL-10, IL-12 or IFNgamma are therapeutic options in
asthma that warrant further investigations.
PMID- 9756181
TI - IgE-Fc epsilonRI-mast cell axis in the allergic cycle.
AB - The IgE and allergen dependent activation of mast cells via the high affinity IgE
receptor (Fc epsilonRI) resulting in the release of inflammatory mediators is
critical to the pathogenesis of atopic diseases like bronchial asthma and
allergic rhinitis. However, mast cells are also involved in certain IgE
independent biological responses, and recent studies have highlighted the role of
mast cells in host defense. In the light of this background, we have discussed
our recent data on the immunophenotypic characteristics of nasal mast cells in
patients with perennial allergic rhinitis (PAR) and chronic infective rhinitis
(CIR) based on the expression of cytokines, the Fc epsilonRI, the cell-bound IgE,
as well as the IgE-mediated mediator release (before and after saturation of the
IgE receptors). Although nasal mast cells (NMC) from both groups of patients
expressed a variety of cytokines, significant differences were observed in the
proportion of cytokine expressing cells between PAR and CIR. NMC from PAR
patients exhibited increased Fc epsilonRI expression, cell-bound IgE and IgE
mediated mediator release as compared with NMC from CIR patients, even after
saturation of the IgE receptors. The density of IgE receptors and IgE molecules
in NMC of PAR patients correlated well with the levels of serum IgE, and IL-4
upregulated the expression of the Fc epsilonRI in NMC. Moreover, NMC from PAR
patients induced IgE synthesis in B cells. Taken together, these results and the
recently demonstrated IgE-induced upregulation of the Fc epsilonRI expression in
mast cells suggest critical roles for mast cells in promoting the allergic
reaction through an IgE-Fc epsilonRI-mast cell axis.
PMID- 9756182
TI - The role of adhesion molecules in allergic inflammation and their suitability as
targets of antiallergic therapy.
AB - Adhesion molecules on leukocytes and tissue-resident cells are now known to
mediate steps of the allergic inflammation response. Blockade of adhesion
pathways is being actively explored as a potential strategy to therapeutically
manage allergic diseases. The various adhesion molecules and their counterligands
are discussed with respect to evidence supporting their role in allergic
inflammation and suitability as therapeutic targets.
PMID- 9756183
TI - The role of theophylline and phosphodiesterase4 isoenzyme inhibitors as anti
inflammatory drugs.
AB - Theophylline has been used for over a century in the treatment of asthma and
while it is used principally as a bronchodilator, a number of recent studies have
demonstrated potential anti-inflammatory and immunomodulatory activity. Indeed,
regular treatment with low-dose theophylline, affords significant clinical
benefit at the expense of unwanted side-effects associated with this drug,
including headache and vomiting. The mechanism of action of theophylline is
unclear, although a significant body of evidence points to an involvement of
phosphodiesterase enzyme inhibition. Phosphodiesterases are a diverse group of
enzymes that belong to at least seven families and of particular interest is the
role of phosphodiesterase 4 isoenzyme as it is distributed in a number of
inflammatory and immune cells and whose inhibition results in the downregulation
of inflammatory and immune cell function. The discovery of pharmacological drugs
selective for this isoenzyme has been viewed with interest in light of the
positive results from preclinical and early clinical studies. Whether orally
active safe phosphodiesterase 4 isoenzyme inhibitors will be useful in the
treatment of asthma remains to be established.
PMID- 9756184
TI - Theophylline and airway inflammation.
AB - The view of theophylline as a second-line bronchodilator in asthma therapy has
begun to be reconsidered in recent years as the details of its additional actions
on airway inflammation have emerged. Increasing understanding of the mechanisms
of action of theophylline has led to an appreciation of the ways in which this,
and other related drugs, may influence the development and maintenance of the
airway inflammation that underlies asthma through alteration of inflammatory cell
function. In addition, recent demonstrations that theophylline can suppress late
phase asthmatic reactions at serum concentrations below those traditionally
regarded as therapeutically useful have provided evidence that theophylline's
beneficial actions in asthma extend beyond mild bronchodilation. The apparent
suppression of airway inflammation by theophylline in asthmatic patients
reinforces data from ill vitro experiments, showing inhibitory actions of
theophylline on the pro-inflammatory functions of many immune cells. Here, we
review some recent advances in the understanding of theophylline's actions that
suggest its role as an anti-inflammatory drug in asthmatic airways.
PMID- 9756185
TI - Asthma, adenosine, mast cells and theophylline.
AB - Many clinical trials have suggested that theophylline has anti-inflammatory
properties in the treatment of bronchial asthma. Proposed mechanisms of
theophylline inhibition include phosphodiesterase inhibition, an adenosine
receptor antagonist, the increase of circulating adrenaline, mediator antagonist
and inhibition of calcium ion influx. Further to these observations we report on
the inhibition by theophylline of NF-kappaB, a key transcription factor found in
human purified mast cells, which plays a role in the transcription of TNF alpha,
GM-CSF, and IL-8 within this cell. The suppression of NF-kappaB activation,
indicates that theophylline, in addition to its bronchodilator activities, has
the potential for anti-inflammatory activity.
PMID- 9756186
TI - Theophylline inhibits the release of eosinophil survival cytokines--is Raf-1 the
protein kinase A target?
AB - Increased numbers of activated eosinophils in bronchial tissue is a feature of
asthma and may, in part, be attributed to the prolonged cytokine-dependent
survival of eosinophils within the inflamed microenvironment. Low-dose oral
theophylline was previously shown to reduce the number of activated eosinophils
within the sub-mucosa following allergen exposure. A number of inhibitory actions
of theophylline have been described which relate to eosinophil recruitment and
activation, including inhibition of cell migration and release of granule basic
proteins. In this study we investigated the ability of theophylline to inhibit
the release of preformed GM-CSF and IL-8 from eosinophils in vitro, as these
cytokines may serve an autocrine function in eosinophil survival in vivo.
Eosinophils rapidly released GM-CSF and IL-8 spontaneously, and release was
further enhanced in response to sIgA-coated beads. Theophylline inhibited the
stimulated, but not the spontaneous, release of both cytokines. We previously
reported the role of protein kinase A in inhibition of arachidonic acid
mobilization and LTC4 synthesis. Therefore we speculate that cAMP-dependent
activation of protein kinase A following theophylline treatment of eosinophils
resulted in inhibition of Raf-1 and MAPK/MAPKK dependent activation of
phospholipase A2 and consequently inhibition of degranulation and cytokine
release.
PMID- 9756187
TI - Therapeutic activities of theophylline in chronic obstructive pulmonary disease.
AB - Recent observations in asthmatics demonstrated anti-inflammatory and
immunomodulatory activities of theophylline besides the bronchodilating effect.
Theophylline inhibits the mediator release from mast cells, peripheral blood
monocytes and alveolar macrophages. The proliferative response of T-cells as well
as the influx of eosinophils in BAL fluid is inhibited by treatment with
theophylline. The production and release of pro-inflammatory cytokines are
affected by theophylline showing a potent inhibitory effect on the production of
IL-1beta, TNF-alpha and IFN-gamma. The production of the anti-inflammatory
cytokine IL-10 is increased. Evidence is mounting that the anti-inflammatory
effects and immunomodulating actions are exerted at lower plasma concentrations
than those required for bronchodilation. These activities are of relevance in the
treatment of chronic obstructive pulmonary disease (COPD), a disease in which the
inflammatory component is considered to be more important than previously
thought.
PMID- 9756188
TI - Effect of theophylline withdrawal on airway inflammation in asthma.
AB - Theophylline has been used as a bronchodilator in acute and chronic asthma
management, although there is accumulating evidence that it may have anti
inflammatory effects. We have investigated the effect of theophylline withdrawal
for 6 weeks in asthmatic subjects whose peak expiratory flow (PEF) readings were
more than 80% of the predicted value and its variability was less than 20% (Green
Zone) by treatment with both a moderate dose of inhaled corticosteroids (BDP),
400-800 microg/day) and low dose theophylline (400 mg/day) for more than 3
months. In 38 asthmatic subjects, changes in clinical symptoms, respiratory
function and airway inflammation detected with hypertonic saline induced sputum,
and airway reactivity to histamine were investigated. One half of the patients
were randomly withdrawn from theophylline, while the other half continued to take
the same dose of theophylline for a period of 6 weeks. Mean steady state plasma
theophylline concentrations when receiving treatment with theophylline were 8.08
microg/mL in the theophylline withdrawal group and 7.64 microg/mL in the control
theophylline group, respectively. Although a significant increase in asthma
symptoms emerged in the theophylline group, there were no significant changes in
the theophylline administration group. In the theophylline withdrawal group,
there were small but significant falls in PEF in the morning, FEV1 and V50 at the
end of the study period. Analysis of induced sputum showed that there was also a
significant increase in the percentage of total and activated (EG2+) eosinophils
only in those patients who withdrew from theophylline. These results indicate
that chronic treatment with low dose theophylline exerts an anti-inflammatory
effect and that the additional use of theophylline with inhaled corticosteroids
provides an effective treatment for moderate asthma. Taken together, we conclude
that theophylline has long-term beneficial effects on the chronic asthma
management.
PMID- 9756189
TI - Nocturnal asthma and the use of theophylline.
AB - The nocturnal worsening of asthma is a common event in asthma patients. Some
studies have shown the prevalence of nocturnal asthma to be as high as 75% of
patients. It is important to understand this phenomenon as nocturnal asthma is
associated with decreased daytime cognitive function and increased morbidity and
mortality. The exact mechanism for decrements in overnight lung function is not
known. However, there are many different processes associated with nocturnal
asthma. Day-to-night change in both circulating bronchodilating and
bronchoconstricting mediators occur which favour airway narrowing and increased
bronchial hyperresponsiveness at night. The beta2 adrenergic receptors decrease
in both number and function at night which is associated with a genetic
polymorphism, a glycine 16 substitution. Neuroinfluences such as increased
nocturnal cholinergic tone also contribute to nocturnal asthma, and a hallmark of
nocturnal asthma is increased airway inflammation during sleep. Long-acting
theophylline preparations have long been associated with improvement in overnight
lung function. Some of these agents can be used in a chronotherapeutic modality,
that is, higher blood levels at night when the disease is worse and lower blood
levels during the day when lung function is routinely better. Theophylline works
as both a bronchodilator and an anti-inflammatory agent to improve nocturnal
asthma.
PMID- 9756190
TI - Can we predict atopic disease using perinatal risk factors?
PMID- 9756191
TI - Which is the true regulator of TH2 cell development in allergic immune responses?
PMID- 9756192
TI - Immunotherapy--anergy, deviation or suppression?
PMID- 9756193
TI - Restoration of cytokine imbalance by immunotherapy.
PMID- 9756194
TI - The pathogenesis of nocturnal asthma in childhood.
PMID- 9756195
TI - Asthma and respiratory syncytial virus infection in infancy: is there a link?
PMID- 9756196
TI - Perinatal risk factors for atopic disease in conscripts.
AB - BACKGROUND: There is evidence to suggest that atopic disease in adulthood could
be manifestations of events in early life. OBJECTIVES: To investigate the
relationship between perinatal risk factors and the prevalence of allergic
rhinitis and asthma in conscripts. METHODS: A retrospective cohort study, where
information from the Military Service Enrolment Register was linked to the
national Medical Birth Register. The study included 149 398 male conscripts who
were born in Sweden in 1973, 1974 and 1975. Outcome measures were current asthma
and allergic rhinitis recognized at the compulsory military conscript
examinations. RESULTS: Unifactorial analyses demonstrated that number of older
siblings, young maternal age, multiple gestation, prematurity, low birth weight,
growth retardation and perinatal asphyxia were all significantly related to a
decreased risk of allergic rhinitis among male conscripts. The prevalence rates
of allergic rhinitis among conscripts with and without older siblings were 14.1%
and 16.2%, respectively (odds ratio 0.85; 95% confidence interval 0.82-0.87). The
prevalence rates of allergic rhinitis among those with term birth (>36 weeks),
moderately preterm birth (33-36 weeks) and very preterm birth (<33 weeks) were
15.2%, 13.1% and 11.6%, respectively. Older siblings, multiple gestation and
young maternal age were highly significant independent determinants of allergic
rhinitis. By contrast, the effects of prematurity, low birthweight and asphyxia
were weaker and highly correlated. The only independent determinants of asthma
were maternal age, birthweight and multiple gestation. Furthermore, maternal age
and birthweight had opposite effects on asthma and allergic rhinitis.
CONCLUSIONS: In contrast to asthma, allergic rhinitis in young adult men was
strongly associated with perinatal events. This may reflect the close
relationship between allergic rhinitis and atopic sensitization, whereas asthma
has a more multifactorial aetiology.
PMID- 9756197
TI - Comparison between the in vitro cytokine production of mononuclear cells of young
asthmatics with and without immunotherapy (IT)
AB - BACKGROUND: The underlying mechanisms of immunotherapy (IT) are still unknown but
may be related to modifications of cytokine production of T lymphocytes.
OBJECTIVE: In this study we determined the in vitro allergen-induced production
of IL-2, IL-4, IL-5, IL-12 and IFNgamma of peripheral blood mononuclear cells
(PBMC) of eight young asthmatics, aged 15+/-2 years, receiving IT (IT group) and
of eight comparable asthmatics, aged 13+/-3.5 years, who never received IT (non
IT group). METHODS: All patients suffered from perennial asthma and were allergic
to house dust mite (HDM). They were selected if they showed a positive
stimulation index (SI) of PBMC after in vitro incubation with HDM (i.e. SI > 2).
Cells were incubated with and without HDM (10 microg/mL) during 24 h, 48 h and 7
days. Cytokines were determined in the supernatant at the three time points and
are expressed as median values in pg/mL. RESULTS: In the IT group the secretion
of IL-2 was lower compared with the non-IT group after 7 days incubation of PBMC
with HDM (0 vs 33.2, P = 0.008). In both groups maximal secretion of IL-2 was
observed after 48 h. In the non-IT group a high value of IL-2 persisted after 7
days, whereas in the IT group a significant decline of IL-2 occurred after 7
days. Although IL-4 secretion was low in all subjects, more patients of the non
IT group showed detectable IL-4 in the HDM cultures after 24 h and 48 h, although
the difference was not statistically significant (P = 0.08 and P = 0.28,
respectively). Furthermore, IL-4 secretion was lower in the HDM cultures after 24
h in the IT group (1.75 vs 4.1, P = 0.011) and 48 h (2.2 vs 4.1, P=0.035). IL-5
secretion was lower in the HDM cultures after 24h (12.4 vs 47.6, P = 0.035) and
48 h (26.8 vs 135, P = 0.046) in the IT group than in the non-IT group. After 7
days of incubation with HDM there was no difference between the groups. There was
no difference between both groups in secretion of IFNgamma and IL-12.
CONCLUSIONS: These results show a difference in vitro cytokine secretion of PBMC
of asthmatics receiving IT compared with asthmatics who never received IT. PBMC
of patients receiving IT secrete less IL-2 and IL-5 after in vitro incubation
with HDM and show a tendency to secrete less IL-4. The efficacy of IT may be
attributed to a modified cytokine secretion of PBMC.
PMID- 9756198
TI - Impaired NK1.1+ T cells do not prevent the development of an IgE-dependent
allergic phenotype.
AB - BACKGROUND: The induction of TH2 immune responses is critically dependent on
initial IL-4. Although crucial, the source of this early IL-4 has not been
identified. One candidate is a CD1 restricted NK1.1+ T cell subpopulation which
is known to produce such early IL-4. OBJECTIVES AND METHODS: The necessity of
NK1.1+ T cells for the expression of an IgE-dependent phenotype was investigated
in a NK1.1+ T cell deficient mouse model. The allergic phenotype was defined as
immediate cutaneous hypersensitivity. It was induced by immunization of mice with
ovalbumin. Mouse strains used were C57BL/6 mice and C57BL/6 mice homozygous for a
targeted mutation of the beta2 microglobulin gene with consecutive loss of CD1
expression, which leads to a drastic reduction of NK1.1+ T cells. Manifestation
of an allergic sensitization was assessed by intradermal allergen challenge after
i.v. injection of Evans blue solution. The blue stained weal formations were
quantified with the Bonitur method. In addition, the Th2 response was confirmed
by the measurement of cytokines and serum immunoglobulins. The capability to
produce early IL-4 was tested through the assessment of IL-4 mRNA shortly after a
single challenge. RESULTS: Wild type and mutated mice did not differ in any of
the immunological parameters measured. CONCLUSION: A single exposure to antigen
with or without adjuvant induces early IL-4 production in C57BL/6 beta2m-/- mice.
This early IL-4 is therefore independent of the presence of NK1.1+ T cells and
functional MHC class I molecules and leads to IgE production and immediate
cutaneous hypersensitivity.
PMID- 9756199
TI - Prevalence and determinants of house dust mite allergen in East German homes.
AB - BACKGROUND: In 1990/91, allergic sensitization to house dust mites (HDM) and
other allergens was more prevalent in children from West Germany than from East
Germany. OBJECTIVE: To test the hypothesis that low indoor exposure to HDM
allergen in East Germany has contributed to this difference. METHODS: HDM
allergen concentrations were determined in 634 East German dwellings shortly
after the German reunification. RESULTS: HDM group I allergen (Der p 1 + Der f 1)
levels in mattresses (median 2.16, geometric mean 2.07, maximum 278.9 microg/g
dust) and carpets (median 0.41, geometric mean 0.48, maximum 96.3 microg/g dust)
were within the range of levels determined in West Germany in other studies. One
particular East German type of dwelling (light concrete buildings) was associated
with lower mite allergen exposure, but only a minority of the population lived
there. Coal heating, installed in the majority of dwellings before 1989, was
associated with higher allergen exposure. Higher relative humidity (RH) was a
main risk factor for higher Der p 1 exposure (odds ratio [OR] for exposure to >
0.05 microg/g dust on carpets: 1.4 [95% confidence interval (CI) 1.2-1.8] for +
10% RH) but not for higher Der f 1 exposure. Higher temperature was associated
with a lower risk for elevated Der p 1 levels (> 0.05 microg/g dust on carpets):
OR 0.6 (95% CI 0.5-0.8) for + 2 degrees C. CONCLUSION: Mite allergen exposure is
not lower in East Germany than in West Germany. The data does not support the
hypothesis, that low HDM allergen exposure in East Germany is a cause for the
lower prevalence of HDM sensitization in East German children.
PMID- 9756200
TI - Atopic dermatitis in early infancy predicts allergic airway disease at 5 years.
AB - BACKGROUND: Screening tests for atopy risk in newborns have a low predictive
value. If early atopic symptoms and signs could be used as predictors for the
next expected atopic disorder then secondary prevention could be employed. The
aim of this study was to evaluate the capacity of early atopic dermatitis to
predict aeroallergen sensitization and the manifestation of respiratory atopic
disorders at 5 years of age. METHODS: 1314 children of a German prospective birth
cohort study MAS-90 were followed from birth up to 5 years of age. Atopic
dermatitis, asthma and rhinoconjunctivitis were diagnosed from symptoms and signs
at physical examinations and by interviews of the parents. Blood was drawn at 1,
2, 3, and 5 years of age. Aeroallergen sensitization was diagnosed by a specific
IgE value of at least 0.35 kU/L (CAP class > or = 1) against any of five
respiratory allergens (mite, cat, dog, birch, grass). RESULTS: Atopic dermatitis
in the first 3 months was a risk factor for aeroallergen sensitization at 5
years. The risk increased with a positive family history for atopic diseases.
Seventy-seven per cent of children with two atopic parents and early atopic
dermatitis were sensitized against aeroallergens at 5 years, i.e. could have been
predicted in early infancy without any laboratory tests. Although these risk
factors were also significantly associated with the manifestation of allergic
airway disease, the positive predictive value for this outcome at age 5 years was
not yet as high, i.e. 50%. CONCLUSION: Infants with very early signs of atopic
dermatitis and a positive family history are candidates for early intervention
measures against respiratory allergies.
PMID- 9756202
TI - Allergenic relationship among four common and dominant airborne palm pollen
grains from Eastern India.
AB - BACKGROUND: Palm pollen grains are predominant aeroallergens in the tropics
including India. Evidence of allergenic crossreactivity had been reported from
various parts of the world on different families, e.g. Poaceae, Asteraceae, etc.
No such information is available about the palm pollen of tropical countries.
OBJECTIVES: The present study was undertaken to find out the allergenic
relationship, if any, in four common and important palm pollen in India. METHODS:
A 2-year aerobiological survey was carried out at Madhyamgram situated at the
suburban fringe of Calcutta Metropolis using Burkard volumetric sampler to know
the seasonal variation of Areca catechu, Borassus flabellifer, Cocos nucifera and
Phoenix sylvestris among others. Skin-prick tests (SPT) were performed with the
relevant pollen extracts on the respiratory allergic patients. Sera from the
subjects were tested directly by ELISA for estimating the allergen specific IgE.
ELISA inhibitions and dot blotting were performed with pooled patients sera and
four palm pollen extracts to detect the cross-reactivity. RESULTS: Among 70
patients, Areca catechu exhibited the maximum percentage (48.5%) of positive
responses followed by Cocos nucifera (45.7%), Phoenix sylvestris (42.85%) and
Borassus flabellifer (38.5%). On an average, 30-50% of the patients showed
positive skin reactions and enhanced specific IgE level to more than one palm
pollen extract. Further evidence of allergenic crossreactivity among the four
palm pollen grains were provided by dot blotting and ELISA inhibition studies. In
ELISA inhibition, a distinct inhibition was obtained with comparable amounts of
the pollen extracts. CONCLUSION: The suburban aerobiological survey of Calcutta
and SPT results confirmed that the relevant pollen types are significant
contributors of aeroallergen load of the study area. ELISA inhibition studies
with the pooled patients sera using antihuman IgE probe revealed the presence of
shared allergenic components among the four palm pollen grains.
PMID- 9756201
TI - Comparison of skin-prick test and specific serum IgE determination for the
diagnosis of latex allergy.
AB - BACKGROUND: Latex IgE-mediated hypersensitivity has been recognized as an
international health problem. However, there is poor information on the
efficiency of the diagnostic methods available. OBJECTIVE: The purpose of this
study was to specify the efficiency of several diagnostic methods for latex
allergy. METHODS: We designed a prospective study involving 50 adult patients
with latex allergy, as diagnosed by a suggestive clinical history and a positive
skin-prick test (SPT) to a latex extract. One control group of 50 subjects paired
for age, sex, total IgE levels and latex exposure, and another control group of
30 subjects with pollen allergy were used. A low-ammoniated natural-latex and
several glove-latex extracts were elaborated. SPTs with these extracts, as well
as with four different commercial-latex extracts were performed. Latex-specific
serum IgE was determined by the CAP and the AlaSTAT methods. RESULTS: Diagnostic
sensitivity was 98% for the natural-latex extract SPT, from 90% to 98% for the
commercial-latex extract SPT, and from 64% to 96% for the glove-latex extract
SPT. Diagnostic specificity of SPT was 100%, and no severe adverse reactions were
observed during skin testing. With respect to the latex-specific serum IgE
determinations, sensitivity was 86% for the CAP system and 84% for the AlaSTAT
assay, and specificity was dependent on the population considered. CONCLUSION:
SPT with natural latex extracts has shown a diagnostic efficiency close to 100%,
significantly higher than that of latex-specific serum IgE determination.
PMID- 9756203
TI - Expression of two isoforms of Lep d 2, the major allergen of Lepidoglyphus
destructor, in both prokaryotic and eukaryotic systems.
AB - BACKGROUND: The dust mite Lepidoglyphus destructor is a major cause of allergic
diseases among farmers. We have previously cloned and sequenced two isoforms of
the major allergen Lep d 2 (formerly designated Lep d 1) and found significant
homology to group 2 allergens of the house dust mite species Dermatophagoides. We
now report on the production and characterization of recombinant Lep d 2.
OBJECTIVE: We have expressed both isoforms in two different expression systems; a
eukaryotic system, baculovirus in insect cells and a prokaryotic system, E. coli.
We have compared the two systems in regard to production yields and
immunoreactivity of the recombinant allergens. METHODS: The complete cDNA
including the natural leader sequence was cloned into the pBlueBacIII transfer
vector, and the rLep d 2 was produced as a secreted protein in baculovirus. For
the expression in E. coli, the cDNA was cloned into the pET vector, and the rLep
d 2 was produced with six C-terminal histidine residues. The purified recombinant
allergens were tested for immunoreactivity with 10 sera from subjects allergic to
Lepidoglyphus destructor and were compared with native Lep d 2 using inhibition
immunoblotting. The ability of the recombinant allergens to release histamine
from basophils was evaluated using a histamine release assay. RESULTS: Both
expression systems produced immunoreactive recombinant allergens. They inhibited
the binding of human sera to native Lep d 2 confirming their retained IgE binding
properties. The yield of pure recombinant protein from the prokaryotic system was
approximately 1 mg/L compared to the eukaryotic system which produced up to 4
mg/L in an adherent cell culture system. CONCLUSIONS: We have produced
recombinant Lep d 2 in prokaryotic and eukaryotic expression systems which are
comparable to the native allergen. Recombinant Lep d 2 might now be included in
more extensive clinical studies to confirm its usefulness in the in vitro and the
in vivo diagnosis of Lepidoglyphus destructor.
PMID- 9756204
TI - Dysregulation of monocyte differentiation in asthmatic subjects is reversed by IL
10.
AB - BACKGROUND: IL-10 can modulate the differentiation of normal monocytes to
macrophages, increasing the proportion of maturing cells with a phenotype
consistent with T cell suppressive activity. Analysis of the immunopathology in
endobronchial biopsies from asthmatic subjects has revealed significantly reduced
proportions of suppressive macrophage populations associated with chronic T-cell
mediated inflammation. OBJECTIVE: This study investigates whether the altered
homeostasis within the lung macrophage populations in asthma is reflected in
aberrant differentiation of peripheral blood monocytes and whether this
differentiation may be influenced by IL-10. METHODS: Monocytes from 14 normal
individuals and 14 atopic asthmatics were grown in culture for 7 days in the
presence or absence of IL-10, added on day 5. Double immunofluoresence studies
were performed on cytospins of the differentiated macrophages using the
monoclonal antibodies RFD1 and RFD7 to distinguish inductive and suppressive
macrophages by their respective phenotypes. HLADR expression was quantified using
the monoclonal antibody RFDR1. Macrophage function was determined by quantifying
allostimulation in a mixed leucocyte reaction and by measuring TNFalpha and
TGFbeta production. RESULTS: With no cytokine addition the proportion of maturing
macrophages with a suppressive phenotype (D1+D7+) at day 7 was lower in the
asthmatic samples (18%) compared with normals (25%). IL-10 increased the
proportion of suppressive cells in cultures of both asthmatic and normal
monocytes with the increase in the asthmatic subjects (94% increase) being
significantly greater than that in normal subjects (32% increase) (P<0.01).
Asthmatic monocytes had a greater effect in stimulating MLR than normals (P <
0.05) but the addition of IL-10 reduced T cell proliferation in an MLR to a
equivalent level in both groups. CONCLUSIONS: These results suggest that a
fundamental problem may exist in the differentiation of monocytes in asthma which
may be reversed by IL-10.
PMID- 9756205
TI - Inhibition of interleukin-5 mediated eosinophil viability by fluticasone 17
propionate: comparison with other glucocorticoids.
AB - BACKGROUND: Inhaled glucocorticoids are commonly employed to treat patients with
asthma. Eosinophils are important effector cells in the pathogenesis of asthma,
and, in vitro, glucocorticoids modulate eosinophil viability. OBJECTIVE: Using
this glucocorticoid inhibition of eosinophil viability, we compared the in vitro
potencies of several inhaled glucocorticoids with particular attention to
fluticasone 17-propionate. METHODS: Eosinophils from normal or mildly atopic
donors were purified, cultured with cytokines and glucocorticoids, and on day 4,
after staining with propidium iodide, analysed by flow cytometry. RESULTS:
Eosinophil viability was prolonged by interleukin (IL)-5 in a concentration
dependent manner; in contrast, dexamethasone inhibited the IL-5 effect.
Fluticasone 17-propionate, 1.0-1000 nM, also inhibited the IL-5 effect in a
concentration-dependent manner; interestingly, at 0.1 nM fluticasone 17
propionate modestly, but significantly, enhanced eosinophil survival. High
concentrations of IL-5 and granulocyte-macrophage colony-stimulating factor
essentially completely overcame the inhibitory effect of 1000 nM fluticasone 17
propionate on eosinophil survival. In contrast, although interferon-gamma
mediated eosinophil viability was inhibited by 1.0-1000 nM fluticasone 17
propionate, this inhibition was not overcome by increased concentrations of
interferon-gamma. Comparison of the glucocorticoid inhibition of eosinophil
viability in the presence of 10 pg/mL IL-5 resulted in these drug IC50 values (in
nM): fluticasone 17-propionate, 1.3; budesonide, 8.5; triamcinolone acetonide,
25; flunisolide, 32; dexamethasone, 94; beclomethasone 17-monopropionate, 210;
beclomethasone 17,21-dipropionate, 290; and hydrocortisone, >1000. CONCLUSION:
Fluticasone 17-propionate's effect on cytokine-mediated eosinophil viability is
similar qualitatively to other glucocorticoid preparations. However,
quantitatively, fluticasone 17-propionate has the most potent suppressive effects
on IL-5 mediated eosinophil viability among the currently available inhaled
glucocorticoids in the United States.
PMID- 9756206
TI - Phase-contrast microscopic studies using cinematographic techniques and scanning
electron microscopy on IgE-mediated degranulation of cultured human mast cells.
AB - BACKGROUND: Isolating human mast cells is a laborious procedure. Recently,
cultured human mast cells raised from umbilical cord blood cells have become
available. It is necessary to investigate whether IgE-mediated activation of
these cells is mediated by exocytosis. OBJECTIVE: To verify IgE-mediated
activation of these cultured human mast cells morphologically. METHODS: The mast
cells were raised from human umbilical cord blood cells in the presence of stem
cell factor and interleukin-6. IgE-sensitized cultured human mast cells were
activated by anti-IgE, and morphological changes of the cells were examined under
phase-contrast microscopy using cinematographic techniques and scanning electron
microscopy. Histamine release from the cells was measured with high-performance
liquid chromatography. RESULTS: Under the condition in which a significant
histamine release was observed from the mast cells, phase-contrast microscopy
showed that the cultured human mast cells became swollen and extruded granules.
Scanning electron microscopy disclosed the extrusion of smooth and round bodies
from pores formed on the activated mast cell surface. CONCLUSION: IgE-mediated
histamine release from cultured human mast cells is accompanied by exocytosis
morphologically, indicating that cultured human mast cells will help in studying
the functional properties of human mast cells.
PMID- 9756208
TI - Alimentary allergy to pork. Crossreactivity among pork kidney and pork and lamb
gut.
AB - BACKGROUND: A patient suffered from anaphylaxis after the ingestion of pork gut
and kidney, but she tolerated pork meat. Clinical symptoms were also triggered
upon intake of lamb gut. OBJECTIVE: To demonstrate an IgE-mediated
hypersensitivity and identify the pork proteins involved. And also, to study the
possible cross-allergenicity among proteins from lamb gut and pork. METHODS AND
RESULTS: The patient had strong positive skin-prick test responses to pork
kidney, gut and liver, and lamb gut and kidney. RAST technique showed specific
IgE to pork kidney, gut and meat. Immunoblotting after SDS-PAGE disclosed the
presence of four prominent IgE-binding polypeptides in pork kidney (200, 90, 57,
and 47 kDa), two in gut (57 and 27 kDa), and three in meat (51, 40, and 28-30
kDa), apart from other weaker radiostained bands in each extract. The binding of
IgE to 200 and 90 kDa allergens from pork kidney was inhibited by gut from pork
and lamb in immunoblotting inhibition assays. No inhibition was produced by pork
meat. CONCLUSIONS: A mechanism of IgE-mediated hypersensitivity has been
demonstrated in this case of anaphylaxis provoked by pork products. Four main
allergens were detected in pork kidney, two of which (200 and 90 kDa) share
allergenic epitopes with proteins from pork and lamb gut. On the other hand, pork
meat does not seem to have allergenic epitopes in common with pork kidney.
PMID- 9756209
TI - Food allergy with monovalent sensitivity to poultry meat.
AB - BACKGROUND: Allergy to poultry meat is only rarely covered in science. The few
reports are usually related to patients allergic to eggs or bird feathers.
OBJECTIVE: Two patients with a clear history of monovalent, ingestive allergy to
chicken and turkey meat, without other food allergies, were analysed. The
relevant allergens were to be identified by immunoblotting. METHODS: Both
patients were evaluated with skin tests and specific IgE determination (CAP).
Allergens were identified by SDS-PAGE and immunoblotting. Cross-reactivity of
chicken and turkey meat was examined by IgE inhibition experiments. RESULTS: Skin
tests and specific IgE were positive for chicken and turkey in both patients.
Cross-reactivities to other poultry meats were documented for duck and goose
meat. No sensitization to egg components or poultry feathers could be found.
Allergenic proteins of poultry meat were detected at molecular weights of 21, 23
and 50 kDa (distinct bands) and 13, 27 and 33kDa (faint bands). An additional
band at 91 kDa for turkey, can probably not be considered a distinct allergenic
epitope. Immunoblot inhibition confirmed cross-reactivity of chicken and turkey
meat allergens. CONCLUSION: Food allergy to poultry meat is a distinct disorder
with crossreactivity among chicken, turkey and other poultries. The relevant
allergens were identified by immunoblotting. Associated food allergy to egg
components is unlikely as the patients were able to tolerate egg and eggs
products.
PMID- 9756207
TI - Allergen challenge-induced extravasation of plasma in mouse airways.
AB - BACKGROUND: Mouse models are extensively used to study genetic and immunological
mechanisms of potential importance to inflammatory airway diseases, e.g. asthma.
However, the airway pathophysiology in allergic mice has received less attention.
For example, plasma extravasation and the ensuing tissue-deposition of plasma
proteins, which is a hallmark of inflammation, has not been examined in allergic
mice. OBJECTIVE: This study aims to examine the vascular permeability and the
distribution of plasma proteins in mouse airways following exposure to allergen
and serotonin. METHODS: Extravasated plasma was quantified by a dual isotop
technique using intravascular (131I-albumin) and extrasvascular (125I-albumin)
plasma tracers. Histological visualization of fibrinogen and colloidal gold
revealed the tissue distribution of extravasated plasma. RESULTS: Allergen
aerosol exposure (3% OVA, 15min) of sensitized animals resulted in a marked
plasma extravasation response in the trachea (P < 0.01) and the bronchi but not
in the lung parenchyma. A similar extravasation response was induced by serotonin
(P<0.001). Extravasating vessels (assessed by Monastral blue dye) were identified
as intercartilaginous venules. Extravasated plasma abounded in the subepithelial
tissue but was absent in the epithelium and airway lumen. The allergen-induced
response was dose-dependently inhibited by iv administration of formoterol (P <
0.001), a vascular antipermeability agent. CONCLUSION: The present study
demonstrates that serotonin and allergen challenge of sensitized mice increase
airway venular permeability to cause transient extravasation and lamina propria
distribution of plasma in the large airways. We suggest that the extravasation
response is a useful measure of the intensity and the distribution of active
inflammation
PMID- 9756210
TI - Study of a case of hypersensitivity to lettuce (Lactuca sativa).
AB - BACKGROUND: Allergic reactions to lettuce (Lactuca sativa) are not too frequent
and few cases of systemic adverse reactions after its ingestion have been
described. OBJECTIVE: We report a case of clinical sensitization to lettuce on a
patient who presented mucocutaneous manifestations after its ingestion, with
positive skin tests, histamine release test and serum specific-IgE to lettuce.
The allergens responsible for this sensitization were also characterized by means
of SDS-PAGE immunoblotting. MATERIALS AND METHODS: We performed skin tests,
histamine release test, serum specific IgE determination and CAP inhibition with
lettuce and mugwort (Artemisia vulgaris) extracts. An aqueous and enriched
lettuce (from loose leaf type) extract was subjected to SDS-PAGE immunoblotting
for determination of its IgE-binding components. RESULTS AND CONCLUSIONS: CAP
inhibition showed antigenic community between lettuce and mugwort. Four protein
bands from the lettuce extracts with molecular weights of 50, 43, 39 and 16 kDa
exhibited IgE-binding properties.
PMID- 9756211
TI - Is there a correlation between change and progress in nursing education?
PMID- 9756212
TI - Is caring a virtue?
AB - The significance of the question 'Is caring a virtue?' lies in the fact that both
the ethics of virtue and the ethics of care have been proposed as alternatives to
what may be termed 'bioethics'. The ethics of care has been of particular
interest to nursing theorists, especially those who want to say that there is a
body of distinctively nursing ethical theory which is different from bioethics.
In answering the main question there are three supplementary aims: first, to
explore the relationship between virtue ethics and the ethics of care, it is
suggested that caring is not a virtue, but that the virtues involve caring
correctly; second, to give a broad outline of what is meant by an ethics of
virtue, including what it means to care correctly; and third, to examine
implications of the theory for nursing.
PMID- 9756213
TI - Health care reform and the transformation of nursing in Hong Kong.
AB - Health care reform in Hong Kong in the 1990s has brought about dramatic change to
the nursing discipline. This paper reports an ethnographic study which aimed at
exploring the transformation of nursing in a regional hospital in Hong Kong
during this period of reform. In the study, the restructuring of nursing work,
its associated dynamics and resulting impacts upon the nursing profession were
examined. A methodological triangulation approach to data collection encompassing
interviews, participant observation and review of documents was used. The
findings in this study suggest that the majority of nurses working in the case
study hospital continue to be subject to medical dominance and are under
management control. The emphasis on cost-effective care has however, fostered
qualified nurses to claim more ownership of their professional judgement and
autonomy. The health care reform has confirmed the status of two newly
established groups of nurses, the nurse specialists and nurse managers. The
development of the nursing profession is found to be closely connected to its
work development. The preparation of the new generation of nurses, as revealed in
this study, needs to emphasize the cognitive dimension of the professional
competence. Some nurses need to be further educated in specialist practice and
clinical management to maximize the contribution of nursing in health care
delivery.
PMID- 9756214
TI - Fund-holding and contracting for community nursing services: a selective review
of the literature.
AB - In the context of social, political and economic pressures fund-holding has been
described as the 'wild card' in the Health Care Reforms in the United Kingdom of
the 1990s. Set against an international drive to reform health care and increase
the efficient and effective use of resources, fund-holding by general practice is
seen as one means of enhancing the contribution of a primary care led National
Health Service (NHS). It is advocated that a primary care led NHS will enhance
and strengthen the position of nursing in the health care context. In order to
fully exploit such a position it is argued that primary care nurses must adopt a
systems view, recognizing broader strategic issues upon which to base marketing
approaches to the contracting process.
PMID- 9756215
TI - Emphasizing terminal care as district nursing work: a helpful strategy in a
purchasing environment?
AB - This paper describes how within a study on the experiences of district nurses
since the introduction of general practitioner purchasing, participants were
encouraged to describe and define the district nursing service. The
identification of terminal care by district nurses and others as a significant
and defining example of district nursing work is explored and the possible
reasons for its emphasis over other aspects of patient care. The extent to which
terminal care was used within contract and purchasing discussions to aid general
practitioner understanding of district nursing work and achieve extra funding is
described. The paper concludes by questioning the extent to which terminal care
is a helpful and accurate representation of what district nursing work entails,
and the implications there may be in emphasizing one aspect of care within a
purchasing environment.
PMID- 9756216
TI - An exploratory study of demand for the health visiting service within a marketing
framework.
AB - A small exploratory study was carried out to consider the concept of demand for
the health visiting service from the clients' perspective. Because of the
internal market introduced to the British health system under the National Health
Service and Community Care Act, the idea of 'marketing' was used as a conceptual
framework to underpin the study. Guided interviews were carried out with a sample
of nine mothers of pre-school children to elicit the reasons why clients access
the service, what they value about it and how they think it could be improved. A
detailed qualitative analysis of these data indicates that demand for health
visiting relates, in the first instance, to clients' knowledge of the service.
This knowledge, and the extent to which the service meets their expectations,
appear to influence the value the women place on health visiting and their
subsequent use of it. A cycle is described, which illustrates critical points at
which health visiting responses affect demand and use of service. The
implications of the study for health visiting and for marketing the service are
discussed.
PMID- 9756217
TI - The distribution of community psychiatric nurses in England: are they where they
should be?
AB - Given the substantial increase in the numbers of community psychiatric nurses
(CPNs) in England in the last 15 years this paper asks the question: is CPN
activity where it should be? In-other words is activity distributed around the
country according to need? Various indicators of need are suggested including
population age structure, deprivation indices and suicide rates. We find no
evidence -- based on information from scatterplots, Spearman correlations and
more innovative measures of inequality -- that CPNs are distributed according to
need. If this is confirmed by further research it is cause for alarm -- CPNs
should be where they are most needed.
PMID- 9756218
TI - The commissioning of nurse education by consortia in England: a quasi-market
analysis.
AB - The planning and commissioning of nurse education by consortia of NHS trusts and
others in England is examined. These arrangements are analysed in terms of quasi
market theory, investigating their ability to co-ordinate effectively the demand
for nurse education and workforce demand for nurses. Hence the paper examines
evidence concerning the success or failure of consortia to co-ordinate these
aspects, discussing the arguments over nurse and student nurse shortages, and the
procedure for assessing the demand for nurse training places. The paper argues
that current nurse shortages illustrate past planning errors in commissioning
nurse training. Consequently, the central body (National Health Service
Executive) is still aiding consortia in their decision-making concerning numbers
of nurse training places, modelling workforce plans and suggesting increases in
training places (and producing the money to pay for this). As such, it is argued,
the quasi-market is not as yet a completely devolved one. It is suggested in the
concluding discussion that if qualitative benefits of consortia fail to
materialize (as suggested elsewhere), and the quantitative functions are
inadequate, the utility of consortia as planners and commissioners of nurse
education may be questioned.
PMID- 9756219
TI - The captive market in nurse education and the displacement of nursing knowledge.
AB - This paper develops a framework of empowerment within which to examine the
commissioning process for nurse education arising from market reform of the
British National Health Service (NHS). The paper argues that an imbalance in this
commissioning process favours theoretical products, such as the diploma-level
nursing curricula (Project 2000). Also, the university setting of nurse education
is seen as clinically de-skilling both nurse teachers and student nurses as well
as influencing the discourses on clinical skills. The paper further argues that
the effects of such trends are a captive market in nurse education contracting
and a displacement of nursing knowledge. An approach to commissioning nurse
education is described which may counter such trends and positively impact on NHS
organizational development and quality. Further reform of the commissioning
process is described in context of pragmatic health legislation.
PMID- 9756220
TI - Evaluation of a course for charge nurses on caring for people with dementia.
AB - The provision by nurses of appropriate levels of care for people with dementia is
considered to be adversely affected by the inadequate provision of post basic
education. This paper reports on a study that seeks to evaluate the effectiveness
of a brief educational programme for charge nurses caring for people with
dementia. In addition it focuses on behavioural change resulting from the course,
for example, the degree of involvement of relatives in the care of their family
member. The course is seen as a model for short courses for nurses working in
this area. Qualitative methodology was utilized involving questionnaires and
focused group interviews. The evaluation of the course incorporated pre- and post
test design. The study identified factors that enhanced the charge nurses'
educational experience. These factors included a course design incorporating
andragogical teaching methods and the implementation of an action plan. The study
also highlighted problems experienced by charge nurses in implementing an action
plan. The action plan demonstrated that the type of involvement of relatives is
more complex than presupposed and depended on such factors as the fear
experienced by the relative of being left with the responsibility to care for
their family member should they offer to contribute to their care in hospital.
Recommendations for the design of future courses are made.
PMID- 9756221
TI - Enrolled nurse conversion: trapped into training.
AB - The introduction of Project 2000 in the late 1980s aimed to replace the existing
two levels of nurse training with a single level of entry. This entailed phasing
out training for enrolled nurses (ENs) and 'conversion' courses were introduced
to allow ENs to upgrade their qualification. As part of a larger study of
continuing education and training in the National Health Service (NHS), a cohort
of ENs taking part in an open-learning conversion course were interviewed.
Sixteen nurses described their motives for undertaking the course and the impact
of the course on their work and home lives. Data collected in interviews were
analysed using qualitative methods and revealed that all of these nurses felt
under pressure to take part in the course. Participation in the course was
associated with changes in home and work life. The findings of the study have
implications in terms of study leave policy.
PMID- 9756222
TI - Continuing care: developing a policy analysis for nursing.
AB - Continuing care: developing a policy analysis for nursing Many authors have
commented on the invisibility of nursing in policy development, implementation
and analysis. Some of this invisibility may be attributed to the lack of an
easily accessible framework to assist analysis of policy from a nursing
perspective. In this paper we offer a framework for nursing policy analysis based
on the domain concepts of nursing. We use continuing care for older people, a
topical policy issue and fundamental nursing specialty, as a case study to
demonstrate the utility and potential of such a framework in action. The
resulting analysis helps identify areas of potential policy interest to nurses,
raises questions for further policy analysis and offers a coherent position
statement for action.
PMID- 9756223
TI - Specialist practice: advancing the profession?
AB - In 1994, the United Kingdom Central Council for Nursing, Midwifery and Health
Visiting (UKCC) completed its framework for post-registration education and
practice. The UKCC's strategy was based upon the two principles of compulsory re
registration for all practising nurses and graduate-level (or equivalent) entry
to specialist practice. It may be seen as the culmination of a gradual process of
professionalization, as well as a response to changes in the organization and
delivery of health care in the late 20th century. This paper uses both primary
and secondary sources to trace the development of the new strategy, and its wider
implications for the profession.
PMID- 9756224
TI - Intervening to reduce anxiety for women with mild dyskaryosis: do we know what
works and why?
AB - In the United Kingdom women are encouraged to attend their general practice for
cervical smear testing. Those who subsequently receive a mildly dyskaryotic
result are placed under surveillance for 6 months before a further test is
carried out. Receipt of a mildly abnormal result has been found to create anxiety
in some women although it is suggested that this may be relieved by a
specifically designed educational intervention. The qualitative investigation
reported here explored the interaction which occurred during 10 nurse-patient
consultations during which a practice nurse presented an educational intervention
designed to relieve anxiety delivered as part of a randomized controlled trial.
The investigation highlights factors relating to aspects of the intervention
perceived by patients and nurses as successful and as unsuccessful. Implications
for the management of women with mildly dyskaryotic results and for future nurse
led educational interventions are proposed. The need for appropriate training for
practice nurses is underlined. It is suggested that training should aim to assist
the nurse to identify the patient's needs in order that interventions can be
individually tailored and delivered effectively without creating anxiety with
regard to other aspects of health.
PMID- 9756225
TI - Women's lay knowledge of cervical cancer/cervical screening: accounting for non
attendance at cervical screening clinics.
AB - An assessment of women's knowledge of cervical screening and cervical cancer was
considered important as up to 92% of those dying from this form of cancer had
never been tested. What were the reasons which determined their non-attendance?
Issues to be addressed were reactions to invitation, women's knowledge of
screening, and the possible factors which they envisaged as being associated with
cervical cancer. Other issues to be considered were practical problems associated
with attendance, and preference for the sex and professional status of the health
professionals involved; 187 women in a general practitioner practice in Lothian,
Scotland were targeted by questionnaire. As with other studies in this field 50%
of those contacted were ineligible for a variety of reasons. Seventy-two women
completed the questionnaire, providing a mix of qualitative and quantitative
data. Although the majority of women felt the invitation to attend screening was
clear and easy to understand, there was a lack of knowledge with regard to both
the screening itself and the possible causes of cervical cancer. The main
'causes' were seen as higher sexual activity among those aged under 37 and
smoking and a virus by those over 37. The majority of women showed preference for
a female professional to take the smear. Practical problems of time and venue
were not considered insurmountable. The main reasons cited for non-compliance
were the fear and dislike of the test itself.
PMID- 9756226
TI - Evidence-based care of Chinese men having transurethral resection of the prostate
(TURP).
AB - AIM OF STUDY: To measure the effect of specific preoperative information on
postoperative anxiety, satisfaction with information, and demand for analgesia,
of Chinese males having transurethral resection of the prostate (TURP). DESIGN: A
controlled experimental design. The researchers allocated all patients (n = 30)
undergoing TURP in a general hospital in Hong Kong, during a 3-month period, to
one of two groups. The experimental group (n = 15) received a specific
information pamphlet and a general preoperative counselling video. The control
group (n = 15) received a video alone. PROCEDURE AND MEASURES: Following ethical
approval, a researcher took baseline measures of state and trait anxiety using
the Chinese State-Trait Anxiety Inventory (C -STAI). Five days after surgery the
researcher administered the C-STAI (A-State), a patients' satisfaction
questionnaire, and, recorded requests for analgesia during the first 5
postoperative days. RESULTS: Experimental subjects reported significantly lower
anxiety levels post-operatively and a significantly higher level of satisfaction
with the preoperative information, than controls. Postoperative demand for
analgesia did not significantly differ between groups. CONCLUSIONS: The findings
support the importance of providing patients with specific, written preoperative
information about their surgery and its effects to minimize their postoperative
anxiety levels, and improve their satisfaction with the care provided.
PMID- 9756227
TI - The role of the triage nurse practitioner in general medical practice: an
analysis of the role.
AB - A 2-year pilot study was undertaken in a group general practice to evaluate the
nurse practitioner triage role. The study was undertaken in several stages which
included a patient satisfaction questionnaire survey, follow-up interviews with
30 patients from the questionnaire survey, and analysis of the nurse
practitioner's work at different points over the 2-year study period. This paper
describes the work of the nurse practitioner in comparison with that of seven
general practitioners in a group general medical practice over a 5-day period in
February 1996 and included patients' perceptions of their consultation. In this
particular group medical practice, as in others throughout the country, many
patients request same day appointments, often for self-limiting conditions,
social advice and health education. This study demonstrates that the nurse
practitioner can deal with such patients effectively and is undertaking an
expanded and extended role in order to provide an holistic service to patients
with which they are highly satisfied. It can be concluded that given the right
kind of education and training and a supportive framework within the practice,
the nurse practitioner undertaking a triage role can provide a highly effective
service to patients and is a valuable member of the primary health care team.
PMID- 9756228
TI - Are practice nurses an unexplored resource in the identification and management
of alcohol misuse? Results from a study of practice nurses in England and Wales
in 1995.
AB - Changes in the health promotional work undertaken in primary care, including the
work needed to meet the 'Health of the Nation' alcohol targets, have led to a
rapid expansion of the number of practice nurses in England and Wales. However,
there has been little evaluation of this role. This study provides data, for the
first time at a national level, about practice nurses' work in identifying and
managing patients drinking above recommended sensible guidelines. Data were
collected by postal questionnaire from all nurses in a 50% random sample of 1852
practices (drawn from a general practitioner (GP) national study, undertaken at
the same time). 43% of nurses responded from 62% of the targeted practices.
Respondents reported identifying a mean of 3.1 patients per month who were
drinking above recommended sensible guidelines. These patients tended to be male,
above 40 years of age and in contact with the nurse for the first time about this
problem. Most patients were categorized as having a potential alcohol problem;
few were classified as currently dependent. Very little intervention work was
undertaken by nurses except for referral to the GP. If real progress is to be
made in meeting the 'Health of the Nation' targets on population alcohol
consumption, then primary care work in identifying alcohol misusing patients
needs to be developed as a matter of urgency. The patients identified by practice
nurses are those patients relevant to the 'Health of the Nation' alcohol targets.
More emphasis needs to be placed on the valuable contribution practice nurses can
make, particularly through the use of screening instruments and brief
interventions.
PMID- 9756229
TI - Promoting breast feeding: the perceptions of Vietnamese mothers in Sydney,
Australia.
AB - A review of the literature indicated that the majority of Vietnamese mothers
bottle fed their infants after migration to western countries. Those who breast
fed weaned their infants very early. This study aimed to explore, from the
Vietnamese mothers' perspective, their experiences of infant feeding and the
attributes of nurses, midwives, other health professionals and the health care
system that were considered to be important in encouraging the immigrant
Vietnamese women to breast feed in Sydney, Australia. A convenience sample of 124
postnatal Vietnamese women were recruited from the western and southwestern
suburbs of Sydney of New South Wales, Australia. In-depth interviews were
conducted in the privacy of the respondents' homes. An ethnographic approach
guided the concurrent data collection and content analysis. Through constant
comparison of categories, nine concepts emerged from the findings to describe the
women's process of decision making, experiences and perceptions of breast
feeding: believing, complying, rewarding, facing the unexpected, experiencing
pleasure and pain, fulfilling, communicating, counselling and supporting. These
findings highlighted the significance of social, cultural and economic factors
which influenced the women's decisions and maintenance of breast feeding.
Implications for nursing practice and further research are discussed.
PMID- 9756230
TI - Experiences and consequences of pain in persons with post-polio syndrome.
AB - This study describes the meaning of pain and its implications for everyday life
in 35 persons with symptoms of post-polio syndrome. The mean age of the study
group is 65 years and the sex ratio of men to women is 1.5:1. The study persons
were interviewed on two occasions in their homes and answered a pain
questionnaire. The result shows that everyday vocabulary is used to express pain
experiences. The study persons normally answered that it hurt, although the
interviewers used pain in their questions. The results show that the lower back
is the most common location of pain. Joint pains are most common in the upper
extremities. The pain is worst in the evening and at night, and tangibly affects
the daily rhythm. Physical strain and climatic factors commonly provoke pain,
whereas rest and heat give relief. The study show that interviews and pain
questionnaire should be supplemented with questions on activities so as to gain a
comprehensive view of the difficulties experienced in everyday life.
PMID- 9756231
TI - The discursive construction of dementia care: implications for mental health
nursing.
AB - This paper sets out a new approach to dementia that may be used to underpin
mental health nursing practice. The paper begins by examining the development of
community care. Various models of service provision to people with dementia are
then critically examined. As an alternative to these approaches a new model of
dementia is developed which highlights the position of various family members in
the provision of dementia care including the person with dementia and also the
importance of linguistic devices such as narrative and discourse. Finally the
implications of this approach upon the mental health nursing practice are
examined together with various suggestions for the development of research.
PMID- 9756232
TI - Validation of the quality of life scale: living with HIV.
AB - A grounded theory of Salvaging Quality of Life provided the conceptual framework
for the development of the Living with HIV scale which was validated in this
study. The HIV + convenience sample (n = 187) was 66% male, with a mean age of
40.6 years, 69% African-American, and with an average CD4 count of 229 mm3. A
principal components factor analysis with varimax rotation was conducted on the
final 32-item scale and nine factors with Eigenvalues > 1 explained 60% of the
variance. A second order factor analysis of these nine factors resulted in a two
factor solution (HIV Struggles and HIV Reverence) which explained 49.4% of the
variance. Cronbach alpha reliability coefficient for the total scale was 0.84.
Differences between gender, ethnicity, education and presence of an AIDS
diagnosis, and quality of life, were explored. Females had higher total scores
which suggested they had a more positive quality of life than males. The Living
with HIV scale can be used as a method of obtaining input from patients for care
planning and for evaluating the effectiveness of nursing care intervention using
quality of life as an outcome of care.
PMID- 9756233
TI - Triangulation in nursing research: issues of conceptual clarity and purpose.
AB - The controversy concerning the value of qualitative, quantitative and
triangulation approaches to nursing research for understanding human behaviour
and increasing nursing knowledge has been an increasing source of debate among
nurse scholars. However, the differences and similarities of these three
perspectives have not been fully compared as either philosophies or
methodologies. The purposes of this paper are to provide an understanding of the
origin and development of the triangulation research method, clarify major
sources of confusion in the presentation of a triangulation study, and discuss
the problems and possible solutions of a triangulation study. Finally, an example
of multiple triangulation in a nursing research within a Taiwanese cultural
context -- turning points of recovery from cardiac surgery during the intensive
care unit transition -- is presented. In the course of the paper, suggestions are
also given to help nurse researchers recognize when it is most appropriate to use
a certain research method, whether that be qualitative, quantitative or
triangulation.
PMID- 9756234
TI - Staff views on the Resident Assessment Instrument, RAI/MDS, in nursing homes, and
the use of the Cognitive Performance Scale, CPS, in different levels of care in
Stockholm, Sweden.
AB - Multidimensional functional assessment is the basis of individualized care. It is
especially important in the care of elderly, with the complexity of
symptomatology and often with cognitive impairment present. An assessment
instrument for elderly persons, used in this study, is the Resident Assessment
Instrument/Minimum Data Set (RAI/MDS) and its incorporated MDS Cognitive
Performance Scale (CPS). The purposes of the study were to demonstrate the
cognitive performance in elderly persons in different levels of care by using the
CPS and to elicit the views of staff on use of the RAI/MDS. Cognitive impairment
was found in 1276 elderly persons in six levels of care studied, an important
factor to consider when organizing care of elderly. An intervention study was
carried out for 1 year in three nursing home wards, with training and supervision
in implementation of the RAI/MDS including individualized and documented care.
Part of a questionnaire was used to evaluate staff (n = 50) views on using the
instrument. A majority of the staff thought that the RAI/MDS could contribute to
the improvement of quality of care, documentation in nursing records, and in co
operation and engagement. Further research is necessary to elicit more knowledge
on the usefulness and benefits of the instrument.
PMID- 9756235
TI - An analysis of the effectiveness of focus groups as a method of qualitative data
collection with Chinese populations in nursing research.
AB - Although there has been a significant increase in the use of focus groups as a
qualitative method of data collection in health and nursing research, literature
on the use of this method with Chinese populations is limited. This study was
therefore undertaken to explore the contribution of focus groups as a method of
data collection amongst Hong Kong Chinese women. The study involved the
comparison of the data obtained from two concurrent research studies which both
employed case study design and focus groups as a major method of data collection.
In both studies the samples involved Chinese women. The findings demonstrate that
factors such as recruitment to the groups and interaction of group members did
not adversely affect the quality of the data. Indeed the depth of data obtained
on a range of sensitive topics suggests that the use of focus groups provides an
effective method of collecting qualitative data with the Chinese populations in
the described studies. However, a particular issue to emerge from this method of
collection relates to the complexity of transcription and translation of the
Chinese data which in the author's view has implications for the quality of the
data. This finding indicates the importance of undertaking data analysis in the
language of the interview, rather than that of the translated data, to avoid
compromising the quality of data obtained from non-English speaking populations.
PMID- 9756236
TI - Caring in nursing: a multivariate analysis.
AB - The dimensions underlying the perceptions of caring among nurses were
investigated using the Edinburgh Caring Dimensions Inventory (CDI). Exploratory
and confirmatory factor analysis techniques were used. While there was a general
caring factor on which the majority of the items in the CDI loaded, there were
two separable major dimensions to caring, namely 'psychosocial aspects' and
'professional and technical aspects'. In addition, two smaller dimensions were
identified that were both related to self-giving, and it is postulated that these
refer, respectively, to appropriate and inappropriate self-giving in nursing.
PMID- 9756237
TI - The theory-practice gap in nursing: from research-based practice to practitioner
based research.
AB - The aim of nursing research is generally agreed to be the generation of
knowledge, and whilst this is a relevant aim in theory-based disciplines such as
sociology, the primary concern of nursing is with practice. Using examples drawn
mainly from the field of mental health, it will be argued in this paper that the
application of generalizable, research-based knowledge to individual, unique,
person-centred practice, the so-called 'research-based practice' advocated by the
Department of Health, is one of the main causes of the theory-practice gap. It
will be further suggested that nursing requires a paradigm of clinical research
which focuses on the individual therapeutic encounter in order to complement the
existing sociological paradigm of theoretical research which is best suited to
the generation of generalizable knowledge and theory. The paper will conclude by
suggesting that such a clinically based research paradigm must not only focus on
the individual nurse-patient relationship, but that it must be carried out by the
nurse herself. Clinical research, if it is to make a difference to practice, must
therefore be practitioner-based research.
PMID- 9756238
TI - The leading edge. International Nursing Research Conference organized by the
Royal College of Nursing of the United Kingdom Research Society at the James Watt
Centre, Heriot Watt University, Edinburgh, Scotland, 3-5 April 1998.
PMID- 9756239
TI - Estimates of the heights and weights of family members: accuracy of informant
reports.
AB - OBJECTIVE: Information about the accuracy of family informant estimates of height
and weight should assist investigators in evaluating the costs and benefits of
using this type of data in genetic study designs. DESIGN AND METHOD: To assess
the accuracy of family informant estimates, 374 first-degree relatives from 94
Caucasian families, gave estimates about the heights and weights of their first
degree relatives. These estimates were compared with measured heights and weights
to determine their accuracy. RESULTS: Informant estimates were highly predictive
of measured heights (r=0.95), and weights (r=0.94), but informants systematically
overestimated heights (mean=1.4 cm) and underestimated weights of their family
members (mean=4.1 kg). CONCLUSIONS: On average, height estimates were generally
within 1% of the measured height and weight estimates were within 3-5% of the
measured weight. Therefore, these proxy measures can provide useful data, when
measured or self-reported heights and weights are not available.
PMID- 9756240
TI - Metabolic effects of biosynthetic growth hormone treatment in severely energy
restricted obese women.
AB - OBJECTIVE: Severe energy restriction in the treatment of obesity is limited by
catabolism of body protein stores and, consequently, loss of lean as well as fat
tissue. Growth hormone (GH), whose secretion is markedly impaired in obesity, is
endowed with both lipolytic and protein anabolic properties. The aim of this
study was to verify the effects of GH administration on body composition, plasma
leptin levels and energy metabolism in obese patients undergoing severe dietary
restriction. DESIGN: Single-blind placebo-controlled study. Twenty obese women
were fed a diet of 41.86 kJ/kg ideal body weight (IBW) daily for 4 weeks: 10 of
them were randomly assigned to a 4 week treatment with biosynthetic GH (rhGH,
Saizen, Serono, Rome, Italy), 1 U/kg IBW/week in daily subcutaneous injections;
the other 10 patients, matched for age and BMI, received vehicle only. SUBJECTS:
Twenty women with simple obesity (age: 25.4+/-1.07 y, BMI: 35.9+/-0.35 kg/m2).
MEASUREMENTS: Plasma IGF-I and leptin, serum markers of bone turnover (serum bone
isoenzyme of alkaline phosphatase, osteocalcin and urinary hydroxyproline),
nitrogen balance, body composition (by DEXA), and resting energy expenditure
(REE, by indirect calorimetry) were evaluated at baseline and after 4 weeks.
RESULTS: Mean IGF-I plasma levels, not influenced by energy restriction in
patients receiving placebo, displayed a significant increase in the group treated
with rhGH. The mean weight reduction and fat mass loss were not significantly
different in the two groups (6.0+/-0.51 vs 7.2+/-0.30 kg, NS, and 5.36+/-0.460 vs
4.28+/-0.572 kg, NS, with rhGH and placebo, respectively). Likewise, plasma
leptin levels decreased significantly in weight-reduced subjects receiving either
rhGH (from 16.2+/-2.37 to 6.4+/-0.39 ng/ml, P < 0.05) or placebo (from 14.3+/
2.55 to 7.7+/-3.77 ng/ml, P < 0.05). On the contrary, the mean decrease of lean
body mass (LBM) was significantly lower in the GH-treated patients than in those
receiving vehicle (1.52+/-0.60 vs 3.79+/-0.45 kg, P < 0.05). In keeping with
these findings, the mean daily nitrogen balance was significantly less negative
in the GH-treated subjects than in the vehicle-injected patients (mean of the 4
week daily urine collections -185.7+/-40.33 vs -363.9+/-55.47 mmol/d, P < 0.05,
respectively). Further, a significant reduction of mean REE was recorded in the
energy-restricted placebo-treated patients (from 8807+/-498 to 7580+/-321 kJ/24
h, P < 0.05), but not in the patients receiving rhGH (from 8367+/-580 to 8903+/
478 kJ/24 h, NS). Actually, when corrected for LBM, REE was even increased by GH
administration (from 197.9+/-11.76 to 219.3+/-9.87 kJ/kg LBM/24 h, P < 0.05),
whereas it was unchanged in the placebo group (from 201.7+/-13.85 to 190.0+/-9.87
kJ/kg LBM/24 h, NS). A tendency of serum markers of bone turnover to increase was
observed in the patients treated with rhGH, however with no changes in bone
mineral content and density. CONCLUSION: rhGH treatment, though unable to enhance
diet-induced weight and fat mass reduction, was effective in stimulating IGF-I
production and conserving LBM and increasing its energy metabolism even in the
presence of severe energy restriction.
PMID- 9756241
TI - Weight-height relationships among eight populations of West African origin: the
case against constant BMI standards.
AB - OBJECTIVE: To ascertain whether constant body mass index (BMI) standards are
appropriate in genetically similar populations. DESIGN: Data are taken from the
International Collaborative Study of Hypertension in Blacks (ICSHIB), an
observational study. SUBJECTS: Individuals of African descent who were included
in ICSHIB. Subjects lived in eight different sites: Barbados; Cameroon (urban and
rural); Jamaica; Manchester, UK; Maywood, IL; urban Nigeria; and St Lucia.
MEASUREMENTS: Weight and height. RESULTS: Constant BMI standards effectively
argue for the constancy of slope of the linear regression equations of In(weight)
on In(height) across populations. Linear regression results indicate that the
height/weight relationship implied by the use of constant BMI standards, is not
found in these populations and that there is much variation across groups.
CONCLUSION: The use of constant BMI standards in classifying individuals
prognostically may be unwise, even in genetically similar populations.
PMID- 9756242
TI - The effect of six months training on weight, body fatness and serum lipids in
apparently healthy elderly Dutch men and women.
AB - OBJECTIVE: To investigate the effect of a six-months training program on changes
in body weight and lipid concentrations, and their interrelationship in elderly
people. DESIGN: Intervention study. The elderly subjects were randomly assigned
to a control group or one of two supervised aerobic training groups, either all
round activities or ergometer cycling, both exercising 3-4 times a week for six
months. SUBJECTS: 229 elderly men and women, aged 60-80 y. MEASUREMENTS: Various
fatness parameters by anthropometry, serum lipids and peak power output. RESULTS:
During the intervention, no significant changes were observed in weight or body
fatness in subjects of the training groups. Serum high density lipoprotein (HDL),
low density lipoprotein (LDL) and total cholesterol and triglycerides tended to
change in a favourable direction in the elderly of the intervention groups, but
only triglyceride concentration in women of the cycle ergometer group (mean
difference with controls: -0.24 mmol/L, 95% confidence interval (CI): -0.45,
0.03) and total serum cholesterol and HDL-cholesterol concentrations in subjects
of the all-round activity group, (-0.32mmol/L, 95% CI: -0.63, -0.01 and
0.15mmol/L, 95% CI -0.25, -0.05, respectively) were significantly reduced as
compared to controls. Regression analysis showed that the intervention-control
difference in change of all lipids was independent of changes in weight, body fat
and previous engagement in sport activity. CONCLUSION: Regular physical exercise
in an elderly population resulted in favourable changes in serum lipid
concentrations that were not significant, but no change in body weight or
fatness. Change in lipid concentration could not be attributed to change in
weight or body fat.
PMID- 9756243
TI - Agreement of skinfold measurement and bioelectrical impedance analysis (BIA)
methods with dual energy X-ray absorptiometry (DEXA) in estimating total body fat
in Anglo-Celtic Australians.
AB - OBJECTIVE: To compare percentage total body fat (%BF) estimated by the four
skinfold thickness measurement (SKF) and single-frequency bioelectrical impedance
analysis (BIA) methods using three different sets of equations, to that assessed
by the dual energy X-ray absorptiometric (DEXA) method using a Lunar DPX
densitometer. DESIGN: Cross-sectional study. SUBJECTS: An Anglo-Celtic Australian
population of 66 males and 130 females (age: 26-86 y). MEASUREMENTS: %BF by
anthropometry, BIA using three different sets of equations and DEXA. RESULTS:
Mean %BF assessed by DEXA (%BF(DEXA)) was similar to that estimated by SKF
(%BF(SKF)) in males, while %BF(DEXA) was slightly higher in females. %BF
estimated by BIA (%BF(BIA)) was significantly lower than %BF(DEXA) in females,
regardless of equations used for calculation, while the level of agreement
between BIA and DEXA in estimating %BF in males was dependent on prediction
equations used for calculation of %BF(BIA). A better agreement was obtained from
the use on the prediction equations of Segal et al (1988), compared to other two
sets of equations. The agreement between SKF or BIA and DEXA declined with
increasing %BF. CONCLUSIONS: There was a good agreement between DEXA and SKF, and
slightly less so between DEXA and BIA, in estimating %BF in an Anglo-Celtic adult
population. The agreement in most cases, however, was dependent on the degree of
body fatness. In comparison to DEXA, both SKF and BIA, with the use of the
equations of Segal et al (1988), are applicable to estimate %BF in an Anglo
Celtic Australian population.
PMID- 9756244
TI - Coping, personality and the development of a central pattern of body fat from
youth into young adulthood: The Amsterdam Growth and Health Study.
AB - OBJECTIVE: It has been suggested that coping behaviour, in particular a defeat
reaction to stress, is a determinant of the central pattern of body fat. To
verify this hypothesis, this study investigated if coping behaviour, and
associated personality traits, are associated with a central pattern of body fat
or total body fatness in a healthy population of males (n=83) and females (n=98)
early in life. METHODS: Problem-focused, emotion-focused and type A behaviour
were measured at the mean ages of 21 y and 27 y. Personality traits (inadequacy,
social inadequacy, dominance, rigidity and debilitating anxiety), a central
pattern of body fat (subscapular/triceps, (S/T) ratio) and total body fatness
(sum of four skinfolds (SSF): biceps, triceps, subscapular, suprailiac) were
measured six times between the ages of 13-27 y. RESULTS: In both genders, no
association was found between either coping strategy and a central pattern of
body fat or total body fatness. In males, type A behaviour was significantly
negatively correlated with the S/T ratio (r = -0.27, P=0.01) after adjustment for
total body fatness, at the mean age of 27 y. In a longitudinal analysis, adjusted
for total body fatness, dominance and rigidity were negatively associated with
the S/T ratio (beta = -0.09, 95% confidence interval (95% CI) (-0.17; -0.00) and
beta = -0.11, 95% CI (-.19; -0.02), respectively) between the ages of 13-21 y in
males. These associations of type A behaviour, dominance and rigidity, with a
central pattern of body fat, were weaker and did not reach statistical
significance with total body fatness. CONCLUSIONS: The results of this study
justify further research on the association between coping behaviour, personality
and the development of a central pattern of body fat.
PMID- 9756246
TI - Gender differences in fat mass of 5-7-year old children.
AB - OBJECTIVE: Studying gender differences in fat mass and distribution in a
homogeneous group of children. DESIGN: Cross-sectional study. SUBJECTS: 610
children aged 5-7 y in Kiel, Germany. METHODS: Anthropometric measures,
bioelectrical impedance analysis (BIA). RESULTS: Although boys had increased body
weights (P<0.05), body mass indexes (BMI's) (P<0.001) and waist/hip ratios (WHRs)
(P<0.001), the %fat mass as assessed by BIA (P<0.05) was increased in girls.
Although the increased BMI in boys was independent of the percentile used, gender
differences (that is, lower values for boys than for girls at the same age) in
WHR, the sum of four skinfolds and %fat were seen up to the 90th percentile. By
contrast, above the 90th percentile there were no differences in skinfold
thickness and %fat between boys and girls. Studying 42 BMI-matched pairs (boys
and girls) also showed that the %fat estimated by BIA (P<0.001) was increased in
girls. Plotting the average of %fat as obtained from skinfold- and BAI
measurements against the difference between data obtained by the use of the two
methods shows that BIA %fat overestimates skinfold %fat at low or normal percent
fat mass (that is, up to 20%) in both genders. By contrast, at increased fat
mass, BIA %fat seems to underestimate skinfold %fat in both genders. CONCLUSIONS:
Gender differences in fat mass and fat distribution are obvious in children aged
5-7 y. These differences are independent of gender differences in body weight.
However, the nutritional state has an influence and gender differences cannot be
detected in overweight and obese children. Our data also suggest that a children
specific formula used to calculate %fat from skinfold measurements is
inappropriate.
PMID- 9756245
TI - Substrate oxidation and thyroid hormone response to the introduction of a high
fat diet in formerly obese women.
AB - OBJECTIVE: To investigate the adaptation in substrate utilization to a sudden
change in dietary composition from a medium fat to a high fat diet, during a
three day period in formerly obese and never obese women. METHODS: Energy
expenditure (EE) and substrate oxidation rates were measured in eight healthy
formerly obese women and eight never obese controls, during four consecutive days
in a respiration chamber. The first day and the day prior to the experiment, the
subjects consumed a diet with 30 energy-% fat, whereas the diet had 55 energy-%
fat on the subsequent three days. RESULTS: The rate of adjustment of oxidative
substrate partitioning expressed as 24 h non-protein respiratory quotient (RQnp)
was similar in the two groups. RQnp on each of the days was also similar between
the two groups, after accounting for a group difference in energy balance, caused
by a non-significantly lower EE in the formerly obese women. However, the
formerly obese subjects, demonstrated a greater suppression of postprandial fat
oxidation after supper, which was unrelated to energy balance. Furthermore, the
formerly obese subjects, in contrast to the controls, exhibited a reduction in
plasma triiodothyronine/thyroxine ratio (T3/T4) following the high fat diet. A
positive correlation between T3/T4 and EE was found in the 16 subjects.
CONCLUSIONS: The formerly obese subjects did not show a slower adaptation rate of
substrate utilization when challenged with a high fat diet, but exhibited an
enhanced suppression of fat oxidation and a lower T3/T4 ratio after supper, when
fed a high fat diet.
PMID- 9756247
TI - Covert manipulation of energy density of high carbohydrate diets in 'pseudo free
living' humans.
AB - OBJECTIVE: This study examined the effects of varying the energy density (ED) of
high carbohydrate (HC) diets on food and energy intake (EI), subjective hunger
and body weight in humans. DESIGN: Randomised cross-over design. Subjects were
each studied twice during 14 d, throughout which they had ad libitum access to
one of two covertly-manipulated diets. SUBJECTS AND METHODS: Six healthy men
(mean age (s.d.)=32.17 y s.d. (5.26 y), mean weight=69.74 kg s.d. (2.75 kg), mean
height=1.76 m s.d. (0.05 m), body mass index (BMI)=22.57 (2.2) kg/m2) were
studied. The fat, carbohydrate (CHO) and protein content (as % energy) and ED of
each diet were 21:66:13% and 357 kJ/100 g, (low-energy density (LED)) or
22:66:12% and 629 kJ/100 g (high-energy density (HED)). A medium fat diet was
provided at maintenance (1.6 x BMR, MF for 2 d) before each ad libitum period.
Subjects could alter the amount, but not the composition of foods eaten. RESULTS:
Mean EI was 8.67 and 14.82 MJ/d on the LED and HED diets, respectively. Subjects
felt significantly more hungry on the LED diet, than on the HED diet
(F(1,160)38.28; P < 0.001) and found the diets to be similarly pleasant (72.72 mm
vs 71.54 mm (F(1,392)0.31; P = 0.579)). Mean body weight decreased on the LED
diet at a rate of 0.1 kg/d and increased at 0.06 kg/d on the HED diet
(F(1,131)86.60; P < 0.001), giving total weight changes of -1.41 kg and +0.84 kg,
respectively, both of which were significantly different from zero (P < 0.01).
CONCLUSION: Excess EI is possible on HC, HED diets, at least under conditions
where diet selection is precluded. Comparison of these results with previous
studies, which altered ED using fat, suggests that CHO may be a better cue for
hunger than fat.
PMID- 9756248
TI - The metabolic effects of preferential reduction of visceral adipose tissue in
abdominally obese men.
AB - SETTING: This study was performed on free living subjects attending the body
composition laboratory on a monthly basis for a total of six months.
SUBJECTS/DESIGN: Thirty-one abdominally obese men (30
0.95) were enrolled in a placebo-controlled randomized
double-blind study, using either dexfenfluramine (d-fen) or placebo, whilst also
receiving food and fitness counselling. After a two week run-in period they were
randomized to either d-fen or placebo for three months. This was followed by a
further three months without medication, although food and fitness counselling
continued. METHODS: Body composition assessment included anthropometry (weight,
height and abdominal circumferences), dual-energy X-ray absorptiometry (DEXA) for
total body fat, and intra-abdominal fat measured via magnetic resonance imaging
(MRI) at the L3/L4 level. Biochemistry included serum lipids, insulin and
glucose. All measurements including blood pressure were performed at baseline,
three months and six months. STATISTICAL ANALYSIS: The change within each group
in the three months on medication (d-fen or placebo) was assessed by paired t
tests, whilst the difference between the groups at baseline and at three months
(measured by percentage change from baseline) was assessed by unpaired t-tests.
An analysis of variance was performed over the six months for the d-fen group and
the placebo group separately, to determine the overall effect of three months
treatment with either d-fen or placebo, three months after medication had ceased.
OUTCOMES AT THREE MONTHS: At three months, BMI decreased by -5.8+/-0.8% in the
group on d-fen and by -2.7+/-0.8% in the placebo group (P<0.01 d-fen vs placebo).
There was also a significant difference in the reduction of the visceral fat area
between the groups (-21.0+/-4.0% in the d- fen group vs -6.7+/-2.2% in the
placebo group, P<0.01) although there was no significant difference between
groups with regard to reduction in subcutaneous fat area. The
visceral:subcutaneous fat ratio (V/S ratio) was significantly reduced between
groups at three months (-13.3+/-4.9% in the d-fen group vs -0.7+/-3.0% in the
placebo group, P=0.03). At three months, the only metabolic parameters to show
significant difference between the two groups were total cholesterol and LDL
cholesterol. Total cholesterol reduced by -12.4+/-2.0% in the d-fen group
compared with -2.3+/-2.1% in the placebo group (P<0.01). LDL cholesterol reduced
by -15.6+/-2.6% in the d-fen group compared with -1.2+/-2.8% in the placebo group
(P<0.01). OUTCOMES AT SIX MONTHS: In the d-fen group, the reductions in BMI,
abdominal circumference and % total body fat (DEXA) were sustained after three
months on no medication, whereas all changes in body composition seen in the
group on placebo at three months, had reverted at the three month follow-up. Both
groups sustained a reduction in the insulin to glucose (I/G) ratio and systolic
and diastolic blood pressure for three months after medication was ceased, while
those on d-fen initially also maintained a reduction in total and LDL
cholesterol.
PMID- 9756249
TI - Leptin concentrations are associated with higher proinsulin and insulin
concentrations but a lower proinsulin/insulin ratio in non-diabetic subjects.
AB - INTRODUCTION: Leptin (the product of the human OB gene) is increased in obese
individuals, suggesting resistance to its effect. However, there is considerable
variability in leptin levels at each level of body mass index (BMI), suggesting
that genetic and environmental factors may regulate leptin concentrations.
Previous data have suggested that leptin levels are associated with insulin
resistance and in a few reports with impaired insulin secretion. We examined
whether non-diabetic subjects, with elevated specific insulin and proinsulin
levels, had increased leptin levels. METHODS: We used a radioimmunoassay (RIA) to
measure serum leptin levels in 197 non-diabetic Mexican Americans and non
Hispanic whites from the San Antonio Heart Study. We also evaluated whether
leptin levels were associated with impaired insulin secretion or increased beta
cell stress, as evaluated by the fasting proinsulin/insulin ratio. (Higher
fasting proinsulin/insulin ratios are thought to reflect impaired insulin
secretion.) RESULTS: Leptin levels were significantly correlated with fasting
specific insulin (r=0.55, P<0.001) and proinsulin (r=0.57, P<0.001) and inversely
with the proinsulin/insulin ratio (r= -0.154, P=0.035) after adjustment for age,
gender, ethnicity and 2 h glucose. These associations were similar in men and
women and in Mexican Americans and in non-Hispanic whites. After further
adjustment for BMI and waist-to-hip ratio (WHR), leptin levels remained
significantly correlated with specific insulin (r=0.31, P<0.001) and proinsulin
(r=0.24, P<0.001) although the magnitude of the associations were considerably
attenuated. CONCLUSION: We conclude that specific insulin and proinsulin are
positively related to leptin levels and that these associations are to some
degree independent of obesity and body fat distribution. Thus, subjects with
increased insulin levels may be relatively resistant to the effects of leptin.
However, leptin levels are associated with a decrease in the fasting
proinsulin/insulin ratio suggesting that leptin levels are not associated with an
impairment in insulin secretion.
PMID- 9756250
TI - Effect of hydrolyzed guar fiber on fasting and postprandial satiety and satiety
hormones: a double-blind, placebo-controlled trial during controlled weight loss.
AB - OBJECTIVE: To evaluate the effects of a completely soluble fiber on fasting and
postprandial hormone levels, respiratory quotient (RQ) and subjective ratings of
satiety during a controlled weight-loss program. DESIGN: In a five-week
prospective, randomized, double-blind study, a 3.3 MJ (800 kcal)/d diet was
provided during a two-week wash-in period. Then, during the intervention weeks,
separated by a one-week wash-out period, a 3.3 MJ (800 kcal) formula containing
either 20 g fiber or placebo daily, was given in a cross-over design and on days
1, 3 and 7 of the intervention weeks (weeks 3 and 5) measurements were taken
after an overnight fast. SUBJECTS: 25 obese but otherwise healthy females (age:
46+/-6 y, body mass index (BMI): 35+/-6 kg/m2) were studied. MEASUREMENTS: Body
weight; hunger/satiety ratings; glucose, insulin, cholecystokinin (CCK) and
leptin concentrations; RQ during the intervention weeks. RESULTS: In the fasting
state, the supplement had no effect on any of the measured parameters, including
blood concentrations of glucose, insulin, CCK, and leptin, RQ and satiety
ratings. In the 2 h postprandial period following the test meal, none of the
measured parameters differed significantly from that following the non-fiber
supplemented meal, except for the CCK response. CCK demonstrated an overall
higher concentration after the fiber-supplemented meal (P=0.007), even after
adjustment for age, weight, height and treatment sequence. The postprandial peak
in CCK also occurred earlier (at 15 min vs 30 min) after completion of the fiber
supplemented meal. CONCLUSIONS: The results indicated that a hydrolyzed guar gum
fiber supplement produced a heightened postprandial CCK response, but did not
alter other satiety hormones or increase satiety ratings, in either the fasting
or the postprandial state.
PMID- 9756251
TI - Insulin sensitivity in obese normotensive adults: influence of family history of
hypertension.
AB - OBJECTIVE: To evaluate the influence of family history of hypertension on insulin
sensitivity in obese normotensive adults, comparing them with lean subjects.
SUBJECTS: 136 normotensives (N)(mean 24 h blood pressure < 130/80 mmHg; age range
35-45 y): 32 lean (body mass index, BMI < or = 25 kg/m2) N with normotensive
parents (F-), 37 lean N with one or two parents hypertensive (F+), 32 obese (BMI
> or = 30 kg/m2) NF- and, 35 obese NF+. METHODS: 24 h ambulatory blood pressure
monitoring; glucose, insulin and C-peptide before and 30, 60, 90 and 120 min
after an oral glucose load; index of insulin peripheral activity (Ia:
10(4)/insulin x glucose values at glucose peak); fasting insulin/C-peptide ratio
(I/Cp). RESULTS: The four groups were comparable for age, gender and blood
pressure values throughout the 24 h. Glucose, fasting and during test, and I/Cp
were similar among the four groups; insulin and C-peptide, fasting and
stimulated, were significantly higher and Ia lower in obese N than in lean N; at
similar BMI, insulin and C-peptide were significantly higher and Ia lower, in F+
than in F-. The correlation between insulin and BMI was significantly closer in F
than in F+. CONCLUSIONS: Family history of hypertension appears to be
significantly associated with insulin sensitivity in both lean and obese
normotensive adults; moreover, overweight and a genetic predisposition to
hypertension may have additive adverse effects on insulin sensitivity in
normotensive adult subjects.
PMID- 9756252
TI - Body fatness: longitudinal relationship of body mass index and the sum of
skinfolds with other risk factors for coronary heart disease.
AB - OBJECTIVE: To analyse the longitudinal relationships between body mass index
(BMI)/sum of skinfolds (SSF) and biological and lifestyle risk factors for
coronary heart disease (CHD). DESIGN: An observational longitudinal study; that
is, the Amsterdam Growth and Health Study. SUBJECTS: 181 males and females,
initially aged 13 y. Over a period of 15 y, six repeated measurements were
carried out. MEASUREMENTS: BMI and SSF, biological CHD risk factors; that is,
total cholesterol (TC), high density lipoprotein (HDL), TC:HDL ratio,
systolic/diastolic blood pressure (SBP/DBP) and cardiopulmonary fitness (VO2-max)
and lifestyle CHD risk factors (that is, daily physical activity, dietary
parameters, smoking, and alcohol consumption). The longitudinal relationships
were analysed by an autoregressive model, in which the value of the outcome
variable at time-point t is not only related to the value of the predictor
variable at t, but also to the value of the outcome variable at t-1. RESULTS:
Both BMI and SSF were positively related to TC and the TC:HDL ratio. Only BMI was
positively related to SBP and only SSF was negatively related to VO2-max.
Physical activity was negatively related to SSF. None of the other lifestyle
parameters were related to SSF and/or BMI. CONCLUSIONS: Both BMI and SSF were
related to a high risk profile regarding CHD. Different relationships for SSF and
BMI are found, because BMI not only reflects body fatness, but also lean body
mass. Analyses with BMI as an indicator for body fatness should therefore be
interpreted cautiously.
PMID- 9756253
TI - Stimulation by leptin of 3H GDP binding to brown adipose tissue of fasted but not
fed rats.
AB - OBJECTIVES: To assess the effects of intracerebroventricular (i.c.v.) leptin
administration on rats fed ad libitum or fasted on 3H GDP binding to brown
adipose tissue (BAT). SUBJECTS: Groups of 5-6 ten-week-old male Wistar rats.
EXPERIMENTAL DESIGN: An i.c.v. cannula was inserted and unilateral denervation of
interscapular brown adipose tissue (BAT) was performed 5 d before each study.
Thereafter, leptin was infused i.c.v. during 72 h while rats were fed ad libitum
or fasted. Vehicle-infused, pair-fed or fasted rats were used as controls.
MEASUREMENTS: 3H GDP binding to innervated and denervated BAT mitochondria.
RESULTS: 3H GDP binding to innervated or denervated BAT of rats fed ab libitum
compared to vehicle-infused, pair-fed rats was not increased by i.c.v. leptin. 3H
GDP binding was lower in fasted than in fed rats, and the difference was larger
in innervated than denervated BAT. I.c.v. leptin increased 3H GDP binding by 30%
in innervated, and by 51% in denervated BAT (P < 0.05) in fasted rats.
CONCLUSIONS: I.c.v. leptin does not increase 3H GDP binding to BAT of rats fed ad
libitum compared to pair-fed (food-restricted) rats. In contrast, i.c.v. leptin
produces a mild stimulation of 3H GDP binding to BAT of fasted rats. This effect
is not mediated by the sympathetic nervous system, because it is observed in both
innervated and denervated BAT. These results are compatible with the concept
that, in fasting rats, the decrease in leptin secretion contributes to the
reduction in 3H GDP binding to BAT mitochondria.
PMID- 9756254
TI - Hormonal status and NIDDM in the European and Melanesian populations of New
Caledonia: a case-control study. The CALedonia DIAbetes Mellitus (CALDIA) Study
Group.
AB - OBJECTIVE: To assess ethnic differences in androgenic status related to non
insulin-dependent diabetes mellitus (NIDDM) in male and female Melanesians and
Europeans of New Caledonia. DESIGN: This is a case-control study nested in a
prevalence study for diabetes mellitus in the multiracial population of New
Caledonia. SUBJECTS: 186 male subjects were included in the survey (77
Melanesians and 16 Europeans in each case and control group). Each case and
control group included 104 female Melanesian subjects (69 premenopausal and 35
postmenopausal). METHODS: Diabetic subjects were matched for age, gender, ethnic
group and location, with healthy normoglycaemic subjects. Testosterone levels in
men and sex hormone-binding globulin (SHBG) levels in women (measured by
radioimmunoassay, RIA) were compared between NIDDM and control subjects in
relation to obesity, central adiposity and insulin levels. RESULTS: In both
ethnic groups, NIDDM was associated with lower testosterone levels but there was
a marked difference among Europeans. Testosterone was negatively associated with
the body mass index (BMI) (r= -0.35, P <0.01) and fasting insulin (r= -0.37, P
<0.001) in control Melanesians only. In Melanesian women, NIDDM was associated
with lower SHBG levels in pre- and postmenopausal women (P <0.001). SHBG mean
level was not associated with menopausal status. CONCLUSION: Our results confirm
in a Pacific population that NIDDM is associated with low levels of testosterone
in men and low levels in SHBG in women. In contrast to white populations,
Melanesian women have a more androgenic profile, whatever their menopausal
status.
PMID- 9756255
TI - Renal size and composition in hypertensive, obese rabbits.
AB - OBJECTIVE: To determine whether the renal growth associated with obesity is due
to hypertrophy or hyperplasia. DESIGN: New Zealand white female rabbits were fed
either standard rabbit chow (n=17) or chow fortified with 10% corn oil plus 5%
lard (n=18) for 12-16 weeks. MEASUREMENTS: All rabbits were weighed, and intra
arterial blood pressures were successfully measured at the end of the study in 16
lean and 18 obese rabbits; percent water of entire kidneys (8 lean, 8 obese
rabbits) and of defined regions of kidneys (8 lean, 10 obese rabbits) were
obtained gravimetrically. Renal hemoglobin, protein and DNA was measured
chemically (8 lean, 8 obese rabbits). RESULTS: Kidneys grew in size as the
rabbits gained fat. In a series of 8 lean and 8 age-matched obese rabbits,
weighing 3.7+/-0.1 kg and 5.4+/-0.4kg (P<0.05), the kidneys were 20% larger in
the obese rabbits: 15.0+/-0.9 g vs 18.0+/-2.5 g (P<0.05). Kidney protein was also
20% greater in the obese rabbit: 1.38+/-0.06 g/kidney vs 1.66+/-0.06 g/kidney
(P<0.05). While total renal DNA was 16% greater in the obese: 18.2+/-0.5
microg/kidney vs 21.1+/-0.61 g/kidney (P<0.05), no significant difference existed
when the DNA was expressed as microg/mg protein. Fractional water content of the
intact kidney declined with obesity: 78.7+/-1.1% vs 76.0+/-1.2% (P<0.05).
Conversely, the hemoglobin content of the kidney at autopsy, an estimate of the
unstressed vascular volume, increased with obesity: 55+/-19 mg/kidney vs 82+/-25
mg/kidney (P<0.05). By contrast, water content of renal parenchyma was constant:
80.8+/-1.0% vs 80.9+/-1.2% (cortex); 84.0+/-0.8% vs 83.6%+/-2.0% (outer medulla);
and 85.7+/-0.8% vs 86.0+/-2.1% (inner medulla). CONCLUSION: The renal growth
associated with obesity was predominantly hyperplastic and was associated with a
partial exclusion of fluid from the renal sinus.
PMID- 9756256
TI - Analysis of the uncoupling protein-1 (UCP1) gene in obese and lean subjects:
identification of four amino acid variants.
AB - Uncoupling protein-1 (UCP1) is uniquely expressed in brown adipose tissue (BAT)
and of major importance for the tissues thermogenic capacity. This study was
undertaken to detect variants in the UCP1 gene by single strand conformational
polymorphism (SSCP) analysis and subsequent sequencing, and determine their
potential association with obesity. Four variants predicting for amino acid
substitutions were detected, of which Arg40Trp (exon 1) and Lys257Arg (exon 5)
were rare mutations. In contrast, the allele frequency of a polymorphism in exon
2 predicting for an Ala64Thr substitution was 8.2% in a cohort of 293 obese
children and adolescents compared to 4.1% in 134 lean individuals, while the
allele frequency of a Met229Leu variant (exon 5) was not markedly different
between the obese (10.4%) and lean (12.0%) study groups. Although one of the
identified polymorphisms tends to have a higher frequency in obese than in lean
subjects, variants of the UCP1 gene do not seem to contribute significantly to
the development of early-onset obesity in the German population.
PMID- 9756257
TI - Individual effects on biomechanical variables during landing in tennis shoes with
varying midsole density.
AB - The aim of this study was to determine whether individuals responded uniquely to
three different pairs of tennis shoes that differed only in midsole hardness.
Kinematic and kinetic data were collected while the subjects (n = 3) performed a
stereotyped lateral movement wearing each of the three pairs of tennis shoes. The
results were analysed statistically for each subject separately. Variables were
identified as discriminators between shoes for individual subjects based upon the
results of separate discriminant analyses. After these analyses, a multivariate
analysis of variance (MANOVA) was used for each subject to determine whether the
discriminator variables differed significantly between shoes. A scoring system
was devised that used the results of the MANOVA to assign scores to shoes for
each variable. Cumulative scores for shoes (for each subject) were compared to
determine which shoe was best for a subject. The results indicated that each
subject responded uniquely to the shoes, and each demonstrated a preference for a
particular pair of shoes. A need for single-subject designs exists when
evaluating variations in athletic shoes.
PMID- 9756258
TI - Anthropometric-based selection and sprint kayak training in children.
AB - A 12 week kayak training programme was evaluated in children who either had or
did not have the anthropometric characteristics identified as being unique to
senior elite sprint kayakers. Altogether, 234 male and female school children
were screened to select 10 children with and 10 children without the identified
key anthropometric characteristics. Before and after training, the children
completed an all-out 2 min kayak ergometer simulation test; measures of oxygen
consumption, plasma lactate and total work accomplished were recorded. In
addition, a 500 m time trial was performed at weeks 3 and 12. The coaches were
unaware which 20 children possessed those anthropometric characteristics deemed
to favour development of kayak ability. All children improved in both the 2 min
ergometer simulation test and 500 m time trial. However, boys who were selected
according to favourable anthropometric characteristics showed greater improvement
than those without such characteristics in the 2 min ergometer test only. In
summary, in a small group of children selected according to anthropometric data
unique to elite adult kayakers, 12 weeks of intensive kayak training did not
influence the rate of improvement of on-water sprint kayak performance.
PMID- 9756259
TI - Comparisons of the ski turn techniques of experienced and intermediate skiers.
AB - We compared selected kinematic variables for four different ski turn techniques
performed by five experienced and five intermediate male skiers. The four ski
turn techniques were the upstem turn, the downstem turn, the parallel turn and
the parallel step turn. Each turn was divided into the initiation phase and the
first and second steering phases. Most of the statistically significant
differences (P < 0.05) between the two groups were found for the initiation
phases of the four turns. Both the hip axis-hand axis angle and the edging angle
of the uphill ski were significantly different between the two groups for the
upstem turn at the beginning of the initiation phase. For the downstem turn,
significant differences between the groups were found at the start of the
initiation phase for the hip axis-hand axis angle, the shoulder axis-fall line
angle, and the edging angle of the uphill ski. The standard deviation of the
distance between the tips of the two skis over the second steering phase also
differed significantly between the two groups. For the parallel step turn,
significant differences were found at the start of the initiation phase for the
edging angle of the downhill ski and the downhill ski to movement direction
angle. Significant differences were also found for the edging angle of the
downhill ski in the middle of the second steering phase and the shoulder axis to
movement direction angle at the end of this phase. For the initiation phase of
the parallel turn, significant differences were found for the timing of setting
the ski pole, the uphill knee angle at the start of this phase and the range of
the knee angle of the uphill leg from the start to the end of this phase. For
this turn, significant differences between the two groups were also found for the
edging angle of the downhill ski in the middle of the second steering phase and
the shoulder axis to movement direction angle at the end of this phase. One of
the reasons it was possible to identify a few significant differences only for
the turns analysed, was the variability within the intermediate group: for most
of the variables analysed, the standard deviation was much higher for the
intermediate than for the experienced group.
PMID- 9756260
TI - Heart rate, blood lactate and kinematic data of elite colts (under-19) rugby
union players during competition.
AB - Physiological and kinematic data were collected from elite under-19 rugby union
players to provide a greater understanding of the physical demands of rugby
union. Heart rate, blood lactate and time-motion analysis data were collected
from 24 players (mean +/- s(x): body mass 88.7 +/- 9.9 kg, height 185 +/- 7 cm,
age 18.4 +/- 0.5 years) during six competitive premiership fixtures. Six players
were chosen at random from each of four groups: props and locks, back row
forwards, inside backs, outside backs. Heart rate records were classified based
on percent time spent in four zones (>95%, 85-95%, 75-84%, <75% HRmax). Blood
lactate concentration was measured periodically throughout each match, with
movements being classified as standing, walking, jogging, cruising, sprinting,
utility, rucking/mauling and scrummaging. The heart rate data indicated that
props and locks (58.4%) and back row forwards (56.2%) spent significantly more
time in high exertion (85-95% HRmax) than inside backs (40.5%) and outside backs
(33.9%) (P < 0.001). Inside backs (36.5%) and outside backs (38.5%) spent
significantly more time in moderate exertion (75-84% HRmax) than props and locks
(22.6%) and back row forwards (19.8%) (P < 0.05). Outside backs (20.1%) spent
significantly more time in low exertion (<75% HRmax) than props and locks (5.8%)
and back row forwards (5.6%) (P < 0.05). Mean blood lactate concentration did not
differ significantly between groups (range: 4.67 mmol x l(-1) for outside backs
to 7.22 mmol x l(-1) for back row forwards; P < 0.05). The motion analysis data
indicated that outside backs (5750 m) covered a significantly greater total
distance than either props and locks or back row forwards (4400 and 4080 m,
respectively; P < 0.05). Inside backs and outside backs covered significantly
greater distances walking (1740 and 1780 m, respectively; P < 0.001), in utility
movements (417 and 475 m, respectively; P < 0.001) and sprinting (208 and 340 m,
respectively; P < 0.001) than either props and locks or back row forwards
(walking: 1000 and 991 m; utility movements: 106 and 154 m; sprinting: 72 and 94
m, respectively). Outside backs covered a significantly greater distance
sprinting than inside backs (208 and 340 m, respectively; P < 0.001). Forwards
maintained a higher level of exertion than backs, due to more constant motion and
a large involvement in static high-intensity activities. A mean blood lactate
concentration of 4.8-7.2 mmol x l(-1) indicated a need for 'lactate tolerance'
training to improve hydrogen ion buffering and facilitate removal following high
intensity efforts. Furthermore, the large distances (4.2-5.6 km) covered during,
and intermittent nature of, match-play indicated a need for sound aerobic
conditioning in all groups (particularly backs) to minimize fatigue and
facilitate recovery between high-intensity efforts.
PMID- 9756261
TI - Springboard oscillation during hurdle flight.
AB - The relative influences of board-tip rebound and fulcrum setting upon vertical
board-tip oscillation during hurdle flight were investigated to gain insight into
the mechanism by which highly skilled divers are able to make effective contact
with the springboard. Data were collected on running dives executed by 3-m
finalists at the 1995 World Diving Cup (men), the 1996 Olympic Games (women) and
the 1996 US Junior Olympics (boys and girls). Analysis of the vertical board-tip
patterns of motion during hurdle flight revealed substantial deviations from a
regular damped oscillation, particularly during the first excursion above the
horizontal. The latter was characterized by two peaks, the first resulting from
upward momentum and the second due to the board's colliding with the fulcrum. A
regression analysis of the senior divers' data indicated that 83.7% of the
variance in hurdle flight time could be accounted for by the maximum height
reached by the board-tip and only 3.6% by fulcrum setting. We conclude that,
among senior divers, rebound of the springboard was the dominant factor
influencing the length of time required for the board to complete its
characteristic 2.25 and 2.50 cycles before take-off.
PMID- 9756262
TI - The effect of industrial and agricultural pollution on human spermatogenesis.
PMID- 9756263
TI - Time to switch from co-culture to sequential defined media for transfer at the
blastocyst stage.
PMID- 9756264
TI - Testicular sperm extraction and intracytoplasmic sperm injection.
PMID- 9756265
TI - FIGO statements and world experience.
PMID- 9756266
TI - Prevention of ovarian hyperstimulation syndrome: novel strategies.
PMID- 9756267
TI - Infants conceived using in-vitro fertilization do not over-utilize health care
resources after the neonatal period.
AB - Health outcomes during the first year for 95 infants born following in-vitro
fertilization (IVF) were compared with those of 79 naturally conceived controls
whose mothers were of identical parity and similar age. Primigravid women were
enrolled prospectively at 30 weeks gestation, perinatal and neonatal data were
collected during pregnancy and following birth, and details of health care
resource use were obtained from mothers at 4 and 12 months. Median (range) number
of medical problems during the first year tended to be less for IVF infants, 4 (0
41) versus 5 (0-12) (P = 0.07), whilst total number of visits to health care
workers was similar for IVF and control infants, 19 (2-47) versus 19 (1-47). IVF
infants were more likely to have an excessive number of visits to Early Childhood
Health Care Centres [odds ratio (OR; 95% confidence interval, CI) = 2.44 (1.11
5.56)], but less likely to have an excessive number of visits to general medical
practitioners [OR = 0.45 (0.22-0.93)] and other health care workers [OR = 0.48
(0.23-0.99)]. These data provide some degree of reassurance about medium-term
health outcomes for children conceived using IVF. Although they are more likely
to utilize the resources of neonatal intensive care units, IVF infants do not
appear to have an increased number of medical problems or to over-utilize health
care resources during the remainder of their first year of life.
PMID- 9756268
TI - Persistent pregnanediol glucuronide secretion after gonadotrophin suppression
indicates adrenal source of progesterone in premature ovarian failure.
AB - A 2-3 fold higher urinary pregnanediol glucuronide excretion has been observed in
women with premature ovarian failure, compared with age-appropriate menopausal
women. Progesterone, the precursor of urinary pregnanediol glucuronide, is a
secretory product of either adrenal or ovarian origin. We postulated that
suppression of pituitary gonadotrophin secretion by down-regulation with a long
acting gonadotrophin-releasing hormone agonist, leuprolide acetate, would
decrease ovarian but not adrenal pregnanediol glucuronide. This would demonstrate
a major difference in the ovarian hormonal milieu of these two groups of women.
Four volunteers with premature ovarian failure collected daily first morning
voided urine samples for 1 month prior to leuprolide acetate administration.
Leuprolide acetate was then administered monthly for 3 months while continuing
daily urinary collection. Luteinizing hormone (LH), follicle stimulating hormone
(FSH), and pregnanediol glucuronide were measured in all samples and normalized
for creatinine. Comparisons of pre- and post-median values for luteinizing
hormone (LH), FSH, and pregnanediol glucuronide were made using the Wilcoxon rank
sum test. This demonstrated significant suppression of both LH and FSH.
Pregnanediol glucuronide, however, did not demonstrate a significant decline,
strongly implying an adrenal source of the enhanced excretion. The decreased
pregnanediol glucuronide noted in age-appropriate menopausal women compared with
premature ovarian failure is likely to be a reflection of adrenal ageing.
PMID- 9756269
TI - Steroidogenesis in luteinized granulosa cell cultures varies with follicular
priming regimen.
AB - During follicular development, a co-ordinated gonadotrophin and endocrine
environment is believed to be essential for normal function of the resulting
corpus luteum. Whether differences in the gonadotrophins used to promote
follicular development can have lasting effects on granulosa cells after they
have undergone luteinization and culture, remains to be studied. We measured
steroid production under basal and human chorionic gonadotrophin (HCG)
stimulation in short and long term cultures of luteinizing granulosa cells
obtained from normal ovulatory women undergoing assisted folliculogenesis with
either human menopausal gonadotrophin (HMG) or follicle stimulating hormone
(FSH). Basal progesterone and oestradiol production by luteinized granulosa cells
obtained from follicles stimulated to develop with FSH was significantly greater
than that from HMG derived follicles (P < 0.001). In short term cultures,
treatment with 10 IU HCG caused a 10-fold increase in progesterone release by
cells from FSH stimulated follicles, whereas cells of HMG origin produced only 5
fold more progesterone (P < 0.0001). In cultures that were maintained for 2
weeks, progesterone secretion was reduced, but a similar trend in HCG
responsiveness was observed. These experiments demonstrate that the composition
of the gonadotrophins used to promote follicular development in vivo leads to
differences in granulosa cell steroidogenesis which are evident after
luteinization and culture. They additionally support the notion that the
environment of follicular development will be reflected in the resulting corpus
luteum.
PMID- 9756270
TI - Elevated concentrations of angiogenin in serum and ascitic fluid from patients
with severe ovarian hyperstimulation syndrome.
AB - This study was conducted to investigate the possible role of angiogenin in the
pathogenesis of ovarian hyperstimulation syndrome (OHSS). The study group
consisted of 10 healthy women who developed severe OHSS (group A) following
ovarian stimulation by a long protocol of gonadotrophin-releasing hormone
analogues/human menopausal gonadotrophin for in-vitro fertilization. A control
group B (n = 10) underwent stimulation by the same protocol and did not develop
OHSS. Blood samples were taken from group A on day of admission to hospital for
treatment of OHSS and, in group B, 1 week after oocyte retrieval. In group A,
ascitic fluid was routinely aspirated as a treatment for severe OHSS, and a
peritoneal fluid sample was aspirated transvaginally before oocyte retrieval in
group B. In group A, the mean serum angiogenin, the mean ascitic fluid
angiogenin, the mean serum oestradiol concentration on day of human chorionic
gonadotrophin and the mean haematocrit were 8390 +/- 6836 ng/ml, 2794 +/- 1024
ng/ml, 6300 +/- 2450 pg/ml and 46.6 +/- 4.4 respectively, as compared with 234 +/
91 ng/ml, 254 +/- 105 ng/ml, 1850 +/- 1100 pg/ml and 36.8 +/- 4.6 in group B
respectively. The differences between groups were highly significant for all
parameters. Angiogenin seems to be strongly associated with the formation of
neovascularization responsible for the development of OHSS.
PMID- 9756271
TI - Peri-ovarian adhesions interfere with the diffusion of gonadotrophin into the
follicular fluid.
AB - In previous studies, patients with severe peri-ovarian adhesions have been found
to show low pregnancy rates and a poor response to gonadotrophin stimulation
during in-vitro fertilization (IVF) treatment. The purpose of this retrospective
pharmacokinetic study was to assess the diffusion of exogenous human chorionic
gonadotrophin (HCG) in patients with peri-ovarian adhesions by examining the
concentration of exogenous HCG in the follicular fluid in patients undergoing
down-regulation and IVF due to infertility. The patients underwent laparoscopic
examination for the scoring of peri-ovarian adhesions (using the classification
of adnexal adhesions adopted by the American Fertility Society, a score of 0
means no adhesions, and a score of 32 represents bilateral expanded dense
adhesions). Oocytes were recovered after human menopausal gonadotrophin-human
chorionic gonadotrophin (HMG-HCG) stimulation with gonadotrophin-releasing
hormone agonist. Serum and follicular fluid were collected at the time of oocyte
recovery for measuring the HCG ratio (the follicular HCG concentration to the
serum HCG concentration; a reflection of the diffusion of exogenous
gonadotrophin) by time-resolved fluoroimmunoassay. A negative correlation was
found between the number of oocytes recovered and the peri-ovarian adhesion score
(r = -0.62, P < 0.01). In a given patient, the follicular HCG concentration was
always lower than the serum HCG at the time of oocyte recovery. The HCG ratio in
all samples was 0.9 or less (0.51 +/- 0.20; range, 0.09-0.90). Significant
negative correlations were found between the peri-ovarian adhesion score and both
the follicular HCG concentration (r = -0.80, P < 0.01) and the HCG ratio (r =
0.75, P < 0.01). In conclusion, severe peri-ovarian adhesions interfered with the
diffusion of exogenous gonadotrophin into the follicular fluid during IVF
treatment. Thus, the diffusion of exogenous gonadotrophin into the follicular
fluid may represent a new parameter in the assessment of ovarian blood flow and
IVF outcome.
PMID- 9756272
TI - Effects of repeated abdominal paracentesis on uterine and intraovarian
haemodynamics and pregnancy outcome in severe ovarian hyperstimulation syndrome.
AB - The aims of this study were to investigate the effects of paracentesis on uterine
and intraovarian haemodynamics by colour Doppler ultrasound and the influences of
repeated paracentesis on pregnancy outcome in severe ovarian hyperstimulation
syndrome (OHSS). Forty-one abdominal paracenteses were performed on seven
pregnant women with tense ascites and eight thoracocenteses were performed on
three pregnant women with pleural effusion. Pulsatility index (PI) and maximum
peak systolic velocity (MPSV) of uterine and intraovarian arteries were measured
before and after each intervention. The mean PI of uterine arteries was decreased
significantly after paracentesis, but not after thoracocentesis. Furthermore,
uterine PI was decreased in 13 out of 14 (92.9%) paracenteses with <2500 ml
ascites removed, compared with eight out of 13 (61.5%) with >2500 ml ascites
removed. After paracentesis, there were no significant changes in the
intraovarian PI and MPSV in either group. The 24-hour urine output increased
significantly in the paracentesis group, but not in the thoracocentesis group.
There were no significant changes in haematocrit and electrolytes as a result of
paracentesis. However, gradual falls in serum total proteins and albumin
concentrations were observed in all patients after repeated paracentesis,
necessitating post-paracentesis albumin infusion. There was no significant
difference in miscarriage rates between the two groups. We conclude that repeated
abdominal paracentesis increases uterine perfusion and has no adverse effects on
pregnancy outcome in severe OHSS. Extraction of 2500 ml of ascitic fluid did not
impair uterine perfusion.
PMID- 9756273
TI - Ovarian hyperstimulation syndrome (OHSS) in a spontaneous pregnancy with fetal
and placental triploidy: information about the general pathophysiology of OHSS.
AB - An ovarian hyperstimulation syndrome (OHSS) in spontaneous pregnancies is a very
rare event. Hence, clinicians might make wrong decisions, such as laparotomy,
because of suspicion of an ovarian carcinoma, or severe complications such as
renal insufficiency may develop because the diagnosis and treatment of OHSS are
delayed. Here we report a case of a woman in the 15th week of gestation,
presenting with a partial hydatidiform mole and a triploidy of fetus and
placenta, with an ongoing and severe OHSS even after legal induced abortion. A
low vascular endothelium growth factor (VEGF) concentration (50 ng/ml) was
measured when human chorionic gonadotrophin (HCG) exceeded 1000 IU/l and was
followed by VEGF concentrations >900 ng/ml, when the OHSS developed. The
literature on spontaneous pregnancies associated with OHSS is reviewed, and
possible reasons for the clinical course presented in this study and the reviewed
reports are discussed. The findings in this case contribute to our theory that
VEGF is a causative factor of OHSS, but has no impact on the course of this
disease.
PMID- 9756274
TI - Moderate ovarian hyperstimulation syndrome complicated by deep cerebrovascular
thrombosis.
AB - This report describes two cases that developed moderate ovarian hyperstimulation
syndrome (OHSS) without evidence of haemoconcentration. Both patients developed
serious cerebrovascular thrombosis resulting in hemiparesis, and recovered after
treatment with anticoagulants. This report emphasizes that other factors may
contribute to vascular thrombosis, and illustrates that cerebrovascular accidents
may complicate even moderate OHSS.
PMID- 9756275
TI - Female patients with cystic fibrosis suffer from reproductive endocrinological
disorders despite good clinical status.
AB - Ten women with cystic fibrosis (CF) were evaluated with regard to hormonal
profiles during a natural and a clomiphene citrate (CC) stimulated cycle. Five of
the women were found to be anovulatory during a natural cycle. All women except
one did respond with ovulation to CC stimulation indicating adequate ovarian
response. Neither did they show increased follicle-stimulating hormone (FSH)
concentrations on day 10 after CC treatment confirming normal ovarian reserve.
Clinically the anovulatory women differed from the ovulating in two aspects: more
profound essential fatty acid deficiency (EFAD) and higher peak/basal insulin
response during an oral glucose tolerance test. The anovulatory women had
significantly lower luteal oestradiol and progesterone but higher total
testosterone concentrations when compared to healthy controls and the ovulatory
CF women. The pathological insulin response and high testosterone concentrations
resemble those seen in women with polycystic ovarian (PCO) syndrome. However, the
CF patients in our study had normal ovaries, as deduced from ultrasound
examination and normal luteinizing hormone (LH)/FSH ratio. It is suggested that
EFAD as well as hypersecretion of insulin may be of importance for the observed
ovarian dysfunction. Further studies are needed to evaluate the relation between
ovulatory mechanisms and EFAD in CF women as well as studies to compare
anovulatory CF women with women with PCO syndrome.
PMID- 9756276
TI - Screening male intracytoplasmic sperm injection candidates for mutations of the
follicle stimulating hormone receptor gene.
AB - Follicle stimulating hormone (FSH) is considered to be essential for
spermatogenesis. Therefore, genetic abnormalities of FSH signalling on testicular
Sertoli cells would be expected to affect sperm production negatively in males.
Inactivating FSH receptor mutations have been reported earlier in both males and
females. All affected males had elevated FSH serum concentrations and abnormal
sperm parameters. We postulated that inactivating FSH receptor mutations might be
a cause of oligozoospermia or azoospermia and reviewed the clinical data of 151
male intracytoplasmic sperm injection (ICSI) candidates with special attention to
FSH serum concentrations. The exclusion criteria for mutation screening of the
FSH receptor gene were: a history of operative sterilization or testicular
malignancy, congenital abnormality other than cryptorchidism, and a chromosomal
aberration or a Y-chromosome microdeletion. The inclusion criteria were: male
(ICSI candidate) with azoospermia or oligoasthenoteratozoospermia (OAT) and
elevated FSH serum concentrations. In total, 23 males with OAT and five males
with azoospermia were tested for mutations of the coding sequences and the intron
exon boundaries of the FSH receptor gene by polymerase chain reaction (PCR)
followed by single strand conformation polymorphism analysis (SSCP). Neutral
polymorphisms were readily detected using this technique in both probands and
controls. None of the 28 selected patients showed a pathogenic FSH receptor
mutation. Mutations in the FSH receptor gene are not a common cause of
infertility in ICSI candidates.
PMID- 9756277
TI - Second look after laparoscopic myomectomy.
AB - The goal of this study was to assess the risk of adhesions after laparoscopic
myomectomy. To this end our enquiry was based on observations with a prospective
collection of data. Between October 26, 1990 and October 1, 1996, 45 patients
underwent a second look after laparoscopic myomectomy. Seventy-two myomectomy
sites were checked. The overall rate of postoperative adhesion was 35.6% per
patient. The rate of adhesions per myomectomy site was 16.7%. The factors which
influenced the occurrence of an adhesion on the myomectomy site were posterior
location of the myoma and the existence of sutures. The rate of adhesions on the
adnexa after laparoscopic myomectomy was 24.4%. The factors which influenced the
occurrence of adnexal adhesions were another surgical procedure carried out at
the same time, the existence of adhesions prior to the operation and posterior
location of the myoma. The rate of adhesions after laparoscopic myomectomy is low
and the adhesions rarely involved the adnexa. We recommend that a second-look
laparoscopy be carried out systematically after laparoscopic myomectomy in
patients desiring pregnancy.
PMID- 9756278
TI - Ultrasound tracking of the movement of embryo-associated air bubbles on standing
after transfer.
AB - The aim of this study was to investigate whether standing upright shortly after
embryo transfer has any potential to affect the position of embryos transferred
to the uterine cavity during treatment with in-vitro fertilization (IVF). This
was assessed by ultrasound-guided tracking of embryo-associated air within the
uterine cavity. A prospective study of 93 patients undergoing 101 consecutive
embryo transfers in an IVF programme was carried out. Transvaginal ultrasound
guided embryo transfer was performed with a second ultrasound in standing
position immediately after transfer, allowing the movement of embryo-associated
air to be assessed. No movement occurred in 94.1% (95/101) of transfers, movement
of <1 cm in 4.0% (4/101) of transfers and movement of 1-5 cm in 2.0% (2/101)
transfers. No movement of embryo-associated air out of the uterine cavity, either
into the cervix or the intramural portion of the Fallopian tube, was seen.
Standing shortly after embryo transfer does not play a significant role in the
final position of embryo-associated air and is unlikely to be a factor in
determining the position of embryos transferred to the uterine cavity during
treatment with IVF.
PMID- 9756279
TI - Sequential clomiphene citrate and human menopausal gonadotrophin with
intrauterine insemination: the effect of patient age on clinical outcome.
AB - The purpose of this investigation was to examine the influence of female and male
patient age on pregnancy rates with sequential clomiphene citrate (CC) and human
menopausal gonadotrophin (HMG) ovulation induction with intrauterine insemination
(IUI) therapy after previous CC and IUI treatment failure. A total of 208
patients previously unable to conceive with CC/IUI therapy underwent 416
treatment cycles of sequential CC/HMG with IUI at a university fertility centre
between May, 1991 and August, 1995. Clinical pregnancy rates, live birth rates,
and the effect of female and male partner chronological age were retrospectively
examined. Treatment with sequential CC/HMG with IUI resulted in clinical
pregnancy rates ranging from 5.9 to 23.1% despite previous CC/IUI treatment
failure. Clinical pregnancy rates, live birth rates, and cumulative pregnancy
rates declined significantly in female patients > or = 35 years of age compared
to those < 35 years of age. A statistically significant decline in clinical
pregnancy rates could not be demonstrated as a function of increasing male
partner age. Pregnancy rates in patients undergoing ovulation induction with
sequential CC/HMG with IUI decline significantly with increasing female partner
age.
PMID- 9756280
TI - A prospective analysis of the accuracy of the TEST-yolk buffer enhanced hamster
egg penetration test and acrosin activity in discriminating fertile from
infertile males.
AB - The aim of this study, based on a prospective analysis, was to evaluate the
accuracy of the TEST-yolk buffer enhanced hamster egg penetration test (HEPT) and
acrosin activity in discriminating fertile from infertile males as compared with
the conventional semen profile. The incidence of spontaneous pregnancies was
monitored during a follow-up period ranging between 18-24 months in 62 couples
without untreatable female infertility. The diagnostic accuracy of the HEPT was
significantly higher than that of the conventional semen profile, as evaluated
with fitted ROC curves. The best discriminatory ability was exhibited by a
penetration index (penetrations/oocyte) of 2 as cut-off value. In our series it
gave a positive predictive value of 77.8% and a negative predictive value of
92.3%. Acrosin activity did not show a discriminating power significantly higher
than the conventional semen profile, but an acrosin activity <20 microIU/10(6)
spermatozoa was found only among patients who did not achieve a pregnancy. In
conclusion, this prospective analysis indicates that the TEST-yolk buffer
enhanced HEPT constitutes a significant improvement over the conventional semen
profile in discriminating fertile from infertile males. Acrosin activity could
provide a useful adjunctive test because of the high negative predictive value of
its poor results.
PMID- 9756281
TI - Occupational heat exposure and male fertility: a review.
AB - In humans, as in most mammals, spermatogenesis is temperature dependent. This
temperature dependence has been clearly demonstrated by several experimental
studies showing that artificial increases in scrotum or testicle temperature in
fertile men reduce both sperm output and quality. Our knowledge of the effects of
occupational heat exposure on male fertility comes mostly from a small number of
epidemiological studies. We conducted an extensive review of these published
reports, focusing on methodology and design (retrospective or prospective;
reference group; number of subjects) and principal results (using several
indicators such as the time taken to obtain a pregnancy or sperm
characteristics). We concluded that occupational heat exposure is a significant
risk factor for male infertility, affecting sperm morphology and resulting in
delayed conception. The limits and biases involved in this type of research are
also discussed.
PMID- 9756282
TI - Intracytoplasmic sperm injection as a routine indication in low responder
patients.
AB - The aim of this study was to determine if a low response to gonadotrophin
stimulation could be considered as an indication for intracytoplasmic sperm
injection (ICSI). This prospective study included a total of 96 non-male
infertile couples with six or fewer retrieved oocytes, who underwent 104 in-vitro
fertilization (IVF) cycles between January 1996 and April 1997. They were
randomly divided into two groups for fertilization, one by IVF and the other by
ICSI. Groups were compared in terms of fertilization rates, fertilization
failure, embryo quality, embryos transferred and reproductive outcome. ICSI
provided similar fertilization rates per inseminated oocyte (77.7 versus 70.2%)
and per obtained oocyte (56.5 versus 58.8%) as IVF. Furthermore, equal numbers
(2.2 versus 2.5) and quality of embryos were obtained and comparable pregnancy
(21.1 versus 17.3%) and implantation (14.0 versus 11.1%) rates. Neither the
number of retrieved oocytes, nor patient age was relevant for the fertilization
rates obtained with both techniques. The number of cases with complete
fertilization failure was similar in both procedures. We conclude that the
technique of fertilization is not related to the reproductive outcome of low
responders, and the routine use of ICSI is not indicated.
PMID- 9756283
TI - Combined fresh and frozen embryo transfer resulting in a twin delivery.
AB - We report the delivery of non-identical twins resulting from the combined
transfer of one fresh and one frozen embryo to a 31 year old patient. To our
knowledge, this is the first reported case where both a fresh and a frozen embryo
implanted in the same cycle led to non-identical twins. We conclude that
supernumerary embryos after in-vitro fertilization should be frozen and used in
subsequent cycles, with implantation potentials as high as fresh embryos. The
possibility of mixing fresh and frozen embryos, though rarely needed, should be
considered, particularly when there is only one fresh embryo available for
transfer.
PMID- 9756284
TI - A chronic, low-dose regimen of the antiprogestin ZK 137 316 prevents pregnancy in
rhesus monkeys.
AB - Continual administration of low doses of the antiprogestin ZK 137 316 was
previously reported to permit ovarian/menstrual cyclicity, but disrupt
endometrial growth in macaques. The contraceptive efficacy of this regimen was
tested in female rhesus monkeys (10 per group) treated daily with vehicle
(controls), 0.01 or 0.03 mg ZK 137 316 per kg body weight for 30 days before and
during continual co-habitation with males of proven fertility. Treatment
continued until confirmation of pregnancy or for 5 months after pair-housing with
males. Mating and vaginal sperm were evident in all females. A cumulative
pregnancy rate of 90% (9/10) was observed in the controls. Of the 10 animals
receiving 0.01 mg/kg, four conceived during the first 2 months of pairing (P =
0.06) with no further conceptions. No pregnancies were observed in the 0.03 mg/kg
group (P < 0.01). Timely, overt menses occurred at a higher frequency in the 0.01
mg/kg group than the 0.03 mg/kg group. However, corpora lutea were present in
ovaries from both groups during the last treatment cycle, indicating that ovarian
cycles occurred. Thus, chronic administration of low-dose ZK 137 316 that permits
continued ovarian cyclicity and a high incidence of timely menses, prevents
pregnancy in non-human primates. This regimen may provide a novel method of
contraception for women.
PMID- 9756285
TI - Effect of seminal plasma on capacitation and hyperactivation in human
spermatozoa.
AB - While hyperactivated motility is known to be a concomitant of capacitation, and a
prerequisite for fertilization, the specific interdependence of capacitation and
hyperactivation in human spermatozoa has not been investigated. This study was
designed to determine the effect of seminal plasma contamination on the
expression of hyperactivated motility and the relationship between
hyperactivation and capacitation, since seminal plasma contains decapacitation
factor(s). Seminal plasma was obtained by centrifugation of aliquots of liquefied
semen layered over 1.5 ml 40.5% Percoll and mixed with human tubal fluid (HTF)
medium containing 30 mg/ml human serum albumin (HSA) (HTF) to a final
concentration of 5% (v/v) seminal plasma (SP). Motile spermatozoa were isolated
from the remainder of the semen by swim-up into either HTF or SP medium. Samples
were taken from each treatment immediately post-harvest (0 h) and after 60 min at
37 degrees C (1 h) for hyperactivation and capacitation assessment. The
treatments were then divided into two portions, centrifuged and resuspended in
either HTF or SP, giving HTF control and SP control treatments and two crossover
treatments, 1 h HTF then 1 h SP (H/SP) and 1 h SP then 1 h HTF (SP/H). All tubes
were incubated for a further 60 min at 37 degrees C before aliquots were taken
for hyperactivation and capacitation assessments. Hyperactivation was estimated
using an IVOS v10.6t (Hamilton Thorne Research, Beverly, MA, USA) 60 Hz CASA
instrument, and capacitation was estimated using the chlortetracycline (CTC)
method. The presence of seminal plasma in the capacitation medium for 60-120 min
post-swim-up inhibited the development of hyperactivated motility. This
inhibition was reversible, and was not prevented by preincubation for 1 h in HTF
medium. There was no difference in the CTC binding patterns between treatments at
2 h, indicating that the capacitation-associated membrane changes were not
affected by the presence of a low concentration of seminal plasma. There was no
correlation between percentage capacitated and percentage hyperactivated
spermatozoa for any treatment. Since the proportions of hyperactivated
spermatozoa and capacitated spermatozoa were not related, we conclude that the
processes leading to hyperactivation and to the membrane changes associated with
capacitation are not tightly interlinked and consider this finding to be due to
hyperactivated motility being associated with flagellar movement, while the CTC
assay assesses changes in the Ca2+ levels of the sperm head plasma membrane.
PMID- 9756286
TI - Update on treatment of varicocele: counselling as effective as occlusion of the
vena spermatica.
AB - This prospective randomized study was performed in order to investigate the
effects of interventive treatment or counselling on pregnancy rates in infertile
couples in whose male partners a varicocele was diagnosed. The present report
extends a previous study using the same design. A total of 125 couples were
included in the current study while the previous report comprised 95 couples.
Couples fulfilling the inclusion criteria were allocated randomly either to
interventive treatment (surgical ligation or angiographic embolization of the
spermatic vein) (n = 62) or to counselling as the sole treatment (n = 63).
Couples were followed over the subsequent 12 months and seen at 3-monthly
intervals. At the end of the 12 month period pregnancy rates, as the main outcome
measure, were 29% in the group given interventive treatment and 25.4% in the
counselled group and were not significantly different. The only significant
difference found, regardless of treatment modality, was the wives' age at
admittance: the 34 wives achieving a pregnancy were 28.8 +/- 0.6 years (mean +/-
SE) old while the 91 non-pregnant wives were 31.2 +/- 0.3 years old (P < 0.05).
The study suggests that regular counselling of the infertile couples is as
effective as interventive treatment of varicoceles in achieving pregnancies.
PMID- 9756287
TI - Comparison of various methods of processing human cryopreserved-thawed semen
samples.
AB - We compared the efficacy of various methods of processing cryopreserved-thawed
samples for the recovery of functionally adequate spermatozoa as assessed by the
response to the sperm stress test (SST), an index of temperature activated sperm
membrane lipid peroxidation, and immediate and delayed changes in sperm viability
and motion parameters. Donor semen samples (n = 28) were cryopreserved-thawed and
divided into six equal parts, one part was used as control and the remaining
parts were used to compare five methods of sperm processing as follows: direct
Percoll gradient processing, washing by one-step or stepwise addition of the
washing medium followed by Percoll processing, and washing by one-step or
stepwise addition of the washing medium. Additional samples (n = 10) were
evaluated for the immediate and delayed (6 h at 37 degrees C) impact of one-step
and stepwise washing (without Percoll separation). Compared with wash-only
methods, samples processed using Percoll had a significantly higher SST score (P
= 0.001), motility, rapid spermatozoa (>50 microm/s), curvilinear velocity and
motility index (P < 0.001). Comparing various Percoll methods, direct Percoll
processing resulted in the highest number of motile spermatozoa recovered (P <
0.00001) and a higher SST score based on curvilinear velocity (P = 0.001).
Stepwise washing gave a significantly higher number of motile spermatozoa (P <
0.001) but with a significantly lower SST score based on the concentration of
motile spermatozoa (P = 0.001), motility (P = 0.001) and motility index (P =
0.01). Sperm viability and motion parameters after 6 h of incubation showed no
difference between one-step and stepwise washing. In conclusion, compared with
wash-only methods, Percoll processed samples resulted in the recovery of
spermatozoa with superior quality as assessed by SST and motion analysis. One
step washing of the samples gave an overall comparable recovery compared to the
samples prepared stepwise. Having significantly higher SST scores, similar
viability and the maintenance of motility, one-step washing may be a better
method of processing thawed samples than the stepwise washing.
PMID- 9756288
TI - The outcome of in-vitro fertilization treatment by egg donation and
intracytoplasmatic sperm injection for severe male factor infertility: a
preliminary report.
AB - Due to a paucity of donated eggs, we have excluded, until recently, couples with
severe male factor infertility from our egg donation programme, except for those
who accepted insemination with donor spermatozoa. The purpose of this study was
to assess the feasibility of a shared in-vitro fertilization (IVF)-embryo
transfer treatment whenever the recipients have severe
oligoasthenoteratozoospermia (OTA) and need intracytoplasmic sperm injection
(ICSI) for egg fertilization. The results from 163 consecutive couples with
ovarian failure who underwent 273 cycles of IVF with donated eggs and augmented
with ICSI were analysed. The rate of diploid fertilization was 54.7%; in 92.3% of
the cycles, at least one embryo was available for transfer. Forty-seven clinical
pregnancies were achieved, representing 18.6% conceptions per transfer. The
highest pregnancy rate was achieved in menopausal patients aged 40-45 years
(26.2% per cycle) and the lowest in patients >45 years old (10.8% per cycle, P =
0.03). Overall, 28.8% of the couples achieved a clinical pregnancy. A total of
196 treatment cycles resulted in 46 clinical pregnancies (23.5%) among the
donors. No statistical differences were found in pregnancy rate achieved by the
donors when compared with the recipients. We conclude that ICSI with egg donation
is a reliable treatment in patients with ovarian failure and severe OTA.
PMID- 9756289
TI - Semen quality: is there a paternal effect on pregnancy outcome in in-vitro
fertilization/intracytoplasmic sperm injection?
AB - The objective of this study was to investigate the role of the spermatozoon
(paternal effects) on implantation and pregnancy outcome in in-vitro
fertilization/intracytoplasmic sperm injection (IVF/ICSI). Male individuals of
three types were analysed: infertile men with oligoasthenoteratozoospermia (OAT),
infertile men with normozoospermia and fertile men (donors). Female counterparts
were judged to have comparable egg quality within two groups studied, i.e.
infertile women with pure mechanical (tubal) infertility and recipients of donor
eggs. There were significantly higher differences in implantation and pregnancy
rates in groups using donor spermatozoa and donor egg recipients. Analyses of key
set groups revealed a trend toward a poorer implantation and pregnancy outcome
when comparing OAT versus normozoospermic patients within IVF, but not within
ICSI treatments, in couples with tubal infertility. In couples who were
recipients of donor eggs, no differences were observed between OAT patients
treated by ICSI and normozoospermic patients treated with IVF. No significant
differences were observed in miscarriage rates within any groups studied. In
conclusion, the poorer results observed in OAT patients undergoing IVF may be
secondary to spermatozoal effects due to a high insemination concentration.
Overall, there does not seem to be a significant effect of severe male
infertility (OAT) on implantation and pregnancy outcome. However, this does not
preclude that specific sperm aberrations may exert a negative effect on
embryogenesis and therefore on implantation potential following assisted or in
vivo reproduction.
PMID- 9756290
TI - Exogenous influences on human fertility: fluctuations in sperm parameters and
results of in-vitro fertilization coincide with conceptions in the normal
population.
AB - Intra- and interindividual short-term fluctuations of sperm parameters were
observed in assisted reproduction patients, paralleled by respective fluctuations
of the in-vitro fertilization (IVF) results. To test whether the fertility
fluctuations observed in the clinic were representative for the overall
population, birth statistics of two normal subpopulations (urban and rural) were
studied. There were highly significant parallels in the fluctuations of the
monthly deliveries in both normal subpopulations. Also, there was a significant
correlation when the fluctuation of sperm parameters in IVF patients was compared
with those of a control group. Furthermore, delivery fluctuations in the overall
population were significantly paralleled by fluctuations in sperm parameters and
IVF results around the conception time of these deliveries. In all groups, the
pattern and amplitude of the short-term fluctuations varied from year to year.
Frequently observed peaks in late autumn gave rise to the appearance of a semi
seasonal variation in fertility. The existence of an external influence on
overall male gamete quality must be postulated, which has considerable influence
on the IVF results. This short-term influence might be causally linked to the
factors responsible for the previously found annual variation in human fertility
and possibly for the long-term changes in human reproductive function.
PMID- 9756291
TI - Selenium in human male reproductive organs.
AB - The objective of the study was to obtain information on the concentration and
distribution of selenium throughout the human male reproductive tract. Material
was removed at autopsy from 41 men who had died suddenly and unexpectedly. Semen
samples were also provided from 184 men attending an andrology clinic for
fertility investigation and from 32 healthy volunteers. Significant positive
correlations in the selenium concentration were demonstrated between the
different reproductive organs, the testis having the highest concentrations. No
correlation was found between the concentration of selenium in the genital organs
and liver, kidney or blood, suggesting that its uptake and/or biochemical
activity in the reproductive organs may be controlled by similar mechanisms not
shared by the other organs. No significant age-dependent changes could be
detected in tissue selenium concentrations. In a group of men under fertility
investigation, a significant positive correlation was obtained between seminal
plasma concentrations of selenium and concentrations of spermatozoa in the same
ejaculate. A significant positive correlation between concentrations of zinc and
selenium in the same ejaculates indicated that selenium may arise largely from
the prostate gland.
PMID- 9756292
TI - Triplet pregnancy and delivery after intracytoplasmic injection of round-headed
spermatozoa.
AB - Intracytoplasmic sperm injection (ICSI) of round-headed spermatozoa into mature
oocyte resulted in normal fertilization, embryo development and pregnancy in a 28
year old female. The husband had a long history of primary infertility. Three
ICSI attempts were carried out and fertilization and embryo development occurred
in all trials. However, only the third trial led to a pregnancy, which proved to
be quadruplet after the transfer of four embryos. One embryo vanished and the
remaining triplets were delivered at 35 weeks of gestation by Caesarean section.
Two of the babies, a boy weighing 2000 g and a girl weighing 2250 g at birth were
discharged in a good condition 1 week after delivery and the third baby, a boy
weighing 1550 g, was discharged 3 weeks after delivery.
PMID- 9756293
TI - Insulin-like growth factor binding protein-3 mRNA expression in endothelial cells
of the primate corpus luteum.
AB - Luteinization is associated with endothelial cell proliferation as part of the
extensive angiogenesis necessary to maintain corpus luteum function. However,
following luteal demise, the vasculature regresses and the endothelial cells
disappear. In the rat corpus luteum, the endothelial cells express high
concentrations of insulin-like growth factor-binding protein-3 (IGFBP-3) during
luteolysis, suggesting a role of IGFBP-3 during endothelial cell loss. The aim of
the present study was to determine the occurrence and location of the messenger
ribonucleic acid (mRNA) for IGFBP-3 in the primate corpus luteum, and to
determine whether or not induction of luteal regression is associated with
changes in localization of the message. Marmoset corpora lutea were studied
throughout the cycle. The effects of induced luteolysis were examined 12 h or 24
h after treatment with either a gonadotrophin-releasing hormone antagonist or a
prostaglandin F2alpha analogue, administered during the mid-luteal phase. High
IGFBP-3 expression was recorded in the endothelial cells of the majority of
microvessels and a minority of capillaries surrounding the lutein cells in all
functionally active corpora lutea. Expression declined markedly in regressing
corpora lutea of the late follicular phase. Expression of the IGFBP-3 mRNA in
lutein cells in the control corpus luteum was extremely rare. There were no major
differences in the degree and pattern of IGFBP-3 expression as a consequence of
induced luteal regression although there was an apparent increase in the number
of capillary endothelial cells expressing. Induction of luteolysis resulted in
expression in a minority of lutein cells. These results support the concept that
IGFBP-3 has an autocrine/paracrine role in regulating various cell types in the
primate corpus luteum, including endothelial cells. However, expression of IGFBP
3 mRNA throughout the luteal phase suggests it may regulate angiogenesis and
luteal function rather than endothelial cell death and luteolysis.
PMID- 9756294
TI - Leukocytes in normal-cycling human ovaries: immunohistochemical distribution and
characterization.
AB - We investigated, using an image analysis system, the immunohistochemical
localization of leukocyte subpopulations and human leukocyte antigen (HLA)-DR in
30 normal-cycling human ovaries in order to better understand local immunological
events in human ovaries. All subtypes of T lymphocytes examined (CD3+, CD4+ and
CD8+ cells) were sporadically observed in the stroma and theca layers of
follicles throughout the menstrual cycle (ranging from 4.32 to 6.25 cells/10(-7)
m2, 1.67 to 3.33 cells/10(-7) m2 and 2.33 to 3.44 cells/10(-7) m2, respectively
for the three subtypes), and subsequently, increased in number in atretic
follicles (78.70 +/- 6.90, 31.13 +/- 2.54 and 43.31 +/- 3.35). After ovulation,
the number of T lymphocytes was markedly low in the early and mid corpus luteum
(13.88 +/- 1.62, 4.18 +/- 0.50 and 6.53 +/- 0.45). The number increased in the
late corpus luteum, and was highest in the late degenerating corpus luteum
(255.67 +/- 27.10, 102.12 +/- 7.80 and 137.34 +/- 12.50). HLA-DR was sporadically
positive in fibroblasts in the stroma and theca layers of follicles (means ranged
from 1.25 to 1.82 cells/10(-7) m2), and increased in atretic follicles (24.68 +/-
2.25). HLA-DR+ cells were markedly low in the early and mid corpus luteum (2.16
+/- 0.88), increased in the late corpus luteum, and reached a plateau in the late
degenerating corpus luteum (121.84 +/- 17.73). The great majority of these
increased HLA-DR+ cells were macrophages. Results of our study suggest that T
lymphocytes and/or macrophages play important roles in luteal regression and
follicular atresia in normal-cycling human ovaries.
PMID- 9756295
TI - Effect of smoking on ovarian reserve and ovarian stimulation in in-vitro
fertilization and embryo transfer.
AB - The effect of cigarette smoking on ovarian reserve as measured by basal serum
follicle stimulating hormone (FSH) concentrations, and by the response to a
standard ovarian stimulation protocol, was examined retrospectively in 173
consecutive women (108 non-smokers and 65 smokers) undergoing in-vitro
fertilization (IVF) and embryo transfer treatment. Women who smoked had a higher
mean basal serum FSH concentration (P < or = 0.0001), in particular younger (<36
years) women, and required a statistically significantly higher mean dosage of
gonadotrophins for ovarian stimulation than the non-smokers (48.1 +/- 15.6 versus
38.9 +/- 13.6 ampoules, 75 IU/ampoule; P < 0.0001). A lower mean number of
oocytes was obtained in smokers than non-smokers (6.2 +/- 3.4 versus 11.1 +/-
6.3, oocytes P < or = 0.0001) and the rate of abandoned cycles (18.5 versus 8.5%)
and total fertilization failure (18.5 versus 8.5%) was higher. The clinical
pregnancy rate per cycle in smokers was 16.9% versus 21.3% in non-smokers but
this was not statistically significant. In conclusion, cigarette smoking in women
appears to significantly reduce their ovarian reserve and lead to poor response
to ovarian stimulation at an earlier age.
PMID- 9756296
TI - Presence of transforming growth factor alpha and epidermal growth factor in human
ovarian tissue and follicular fluid.
AB - Intra-ovarian regulation of follicular maturation is modulated by various
factors. Among these, growth factors are important local actors. We examined the
immunohistochemical localization of transforming growth factor alpha (TGF-alpha),
epidermal growth factor (EGF) and epidermal growth factor receptor (EGF-R) in 18
human ovaries. The concentration of TGF-alpha and EGF in follicular fluid was
measured by ELISA. TGF-alpha was detected in oocytes of primordial and early
preantral follicles. Furthermore, staining was observed in granulosa cells of
preantral follicles and in theca cells of preantral, antral and preovulatory
follicles. EGF showed a similar distribution as TGF-alpha. Atretic follicles were
strongly positive for TGF-alpha and EGF. In the corpus luteum, theca lutein cells
were strongly positive for TGF-alpha and EGF. Immunoreactivity for EGF-R was
observed only in the granulosa cells of antral follicles. Follicular fluids from
patients undergoing in-vitro fertilization (IVF) were examined for their content
of TGF-alpha and EGF. TGF-alpha was detected in 37% of the samples. The
concentration ranged from 43 pg/ml to 602 pg/ml. EGF was not detected in any of
the follicular fluids tested. These observations support the participation of
EGF/TGF-alpha in follicular maturation. Furthermore, the presence of TGF-alpha in
follicular fluid and the simultaneous absence of EGF suggests that TGF-alpha
plays a more pronounced role than EGF in oocyte maturation during late follicular
phase.
PMID- 9756297
TI - Expression of interleukin-1 system mRNA in single blastomeres from human
preimplantation embryos.
AB - Gathering knowledge about the molecular events during preimplantation development
is one of the most important challenges in in-vitro fertilization (IVF). The
interleukin-1 (IL-1) system has been shown to be intimately involved in embryonic
implantation. The aim of our study was to detect the major components of the IL-1
system in single blastomeres from human preimplantation embryos and to relate our
findings to the further development of the biopsied embryos in vitro. Single
blastomeres were removed from morphologically normal embryos obtained from
dipronuclear zygotes and examined by reverse transcription (RT)-nested polymerase
chain reaction (PCR). Expression of beta-actin (external standard), IL-1beta, IL
1 receptor antagonist (IL-1ra) and IL-1 receptor (IL-1R) type I mRNA were related
to embryonic development and IVF outcome. Blastomeres from 12 embryos were
examined: beta-actin and IL-1R type I mRNA were detected in all blastomeres
(100%) whereas IL-1beta could be detected in only nine of the blastomeres (75%).
IL-1ra was expressed in only two (17%) of the blastomeres and those were
simultaneously positive for IL-1beta. Both IL-1ra positive embryos were arrested
in development before reaching blastocyst stage. Five embryos (three of them IL
1beta mRNA positive and two IL-1beta mRNA negative) were transferred as
blastocysts; none of the transfers resulted in a pregnancy. We postulate that
embryos expressing IL-1ra mRNA in a detectable amount appear more likely to be
arrested in early developmental stages.
PMID- 9756298
TI - Implications of complete fertilization failure after intracytoplasmic sperm
injection for subsequent fertilization and reproductive outcome.
AB - With the introduction of intracytoplasmic sperm injection (ICSI), couples with
severe male factor infertility have achieved fertilization and clinical pregnancy
rates comparable to other in-vitro fertilization (IVF) patients. However, failure
of fertilization still occurs in some patients despite the utilization of
microsurgical sperm injection techniques. How such fertilization failure after
ICSI might impact later ICSI treatment(s) is unknown. In this investigation,
couples with complete fertilization failure after ICSI treated from August 1993
to August 1996 were identified (index cycle, n = 21). Additionally, fertilization
data from any previous or subsequent infertility treatments were evaluated. Seven
patients (33%) had at least one IVF treatment before the index cycle, although no
deliveries occurred. Of patients with complete fertilization failure in the index
cycle, 48% (n = 10) underwent at least one subsequent ICSI cycle which proceeded
to oocyte retrieval. The remainder (n = 11) elected to discontinue treatment.
Although six subsequent cycles were cancelled due to poor follicular response (<
or = 2 mature oocytes), all patients electing to continue treatment eventually
achieved a subsequent embryo transfer. The clinical pregnancy rate per transfer
was 45.4% for this group; the delivery and ongoing pregnancy rate per transfer
was 36.3%. Review of semen parameters, superovulation characteristics or other
clinical parameters during the three study cycles (pre-index, index, and post
index) was not prognostic of fertilization success or reproductive outcomes in
later treatments. Fertilization failure with ICSI therefore could not be
predicted by prior cycle performance, although total immotility of spermatozoa at
time of oocyte retrieval, total teratozoospermia, and low oocyte yield were
common characteristics of couples experiencing complete fertilization failure
with ICSI. These findings suggest that fertilization failure in one ICSI cycle
does not preclude successful fertilization and delivery in a later ICSI
treatment.
PMID- 9756299
TI - Microtubule and microfilament organization in maturing human oocytes.
AB - Various stages of immature human oocytes were imaged for microtubule,
microfilament and chromatin organization. After germinal vesicle breakdown, a
small microtubule aster was observed near the condensed chromatin. The asters
appeared to elongate and encompass the condensed chromatin. At metaphase I stage,
microtubules were detected in the meiotic spindle. The meiotic spindle in
metaphase II was a symmetric, barrel-shaped structure containing anastral broad
poles, located peripherally and radially oriented. After germinal vesicle
breakdown, treatment with taxol induced numerous cytoplasmic foci of
microtubules, mainly in the cortex of the oocyte. Microfilaments were observed as
a relatively thick uniform area around the cell cortex and were also found near
the germinal vesicle position. After germinal vesicle breakdown, the
microfilaments were seen in both the cortex and around the female chromatin. In
conclusion, this study suggests that both microtubules and microfilaments are
closely associated with the reconstruction and proper positioning of chromatin
after germinal vesicle breakdown and during meiotic maturation in human oocytes.
PMID- 9756300
TI - Influence of oocyte preincubation time on fertilization after intracytoplasmic
sperm injection.
AB - During the intracytoplasmic sperm injection (ICSI) procedure, the collected
oocytes are incubated until just before ICSI. The ideal preincubation time of
oocytes was investigated in 544 treatment cycles. Oocyte retrieval was carried
out 35 h after human chorionic gonadotrophin administration. Oocytes were
cultured for between 1 and 11 h before ICSI. Embryo transfer was performed 48 h
after oocyte collection. The survival, fertilization and cleavage rates of
injected oocytes indicated no statistically significant differences between
oocytes preincubated for different lengths of time. The proportion of good
quality embryos (grades 1 and 2) was lower at 9-11 h of preincubation time than
for all the other preincubation times (P < 0.001). No statistically significant
differences were detected in the pregnancy rate between each group (mean: 15.9%),
although the pregnancy rate at 9-11 h of preincubation time appeared to be low
(7.7%). These results suggest that the oocyte retained sufficient potential for
fertilization between 1 and 9 h after oocyte collection in ICSI. For the
researchers who practise more complex ICSI procedures than IVF, it would be
convenient to be able to perform ICSI at any time between 1 and 9 h after oocyte
collection.
PMID- 9756301
TI - Fatty acid composition of fertilization-failed human oocytes.
AB - The aim of the study was to assess the fatty acid composition of human
fertilization-failed oocytes. A total of 150 unfertilized oocytes from 43 women
undergoing in-vitro fertilization (IVF) were analysed using capillary gas
chromatography. The majority of fatty acids were saturated (79.22%), of which
stearic (38.65%) and palmitic (32.66%) acids were the most abundant. Of the
monounsaturated fatty acids (14.27%) oleic acid was the most abundant (9.77%).
Polyunsaturated fatty acids comprised 6.50% of fatty acids, the n-6:n-3 ratio
being 7.73. The ratio of eicosapentaenoic acid:docosahexaenoic acid was
approximately 5. It is concluded that the most common fatty acids in human
unfertilized oocytes are either saturated or monounsaturated fatty acids, whose
main function is to provide an energy source. A number of differences in fatty
acid composition were observed, in comparison with other biological samples. In
particular, stearic and eicosapentaenoic acids were more prominent, and oleic and
linoleic acids were less prominent; this may reflect some specific peculiarity of
oocyte metabolism.
PMID- 9756302
TI - Monoclonal antibodies against epidermal growth factor prevent outgrowth of mouse
embryos in vitro.
AB - The necessity of epidermal growth factor (EGF) in the process of mouse embryo
development and outgrowth in vitro was studied. Mouse 4-cell stage embryos were
cultured up to spreading stage (outgrowth) in human tubal fluid (HTF) medium
alone (control) or with 10 ng/ml EGF and 1:250 diluted monoclonal antibodies
against EGF (study groups). Hatching and outgrowth were significantly increased
up to 60.9 and 52.4% respectively, while in the control only 33.7 and 20.4%
reached hatching and outgrowth respectively. Moreover monoclonal antibodies
against EGF significantly inhibited embryo development (P < 0.01). Only 5.8% of
the embryos reached the hatching stage and none of them reached the spreading
stage. Our results show that EGF is probably involved in the modulation of early
embryonic growth and in the initiation of implantation.
PMID- 9756303
TI - Ultrasound covers and sonographic gels are embryo-toxic and could be replaced by
non-toxic polyethylene bags and paraffin oil.
AB - The objective of this study was to test the hypothesis that ultrasound covers and
sonographic gels, used during vaginal ultrasound, are toxic for mouse embryonic
development in vitro. A prospective randomized design was used on pronucleate ova
of F1 hybrid CBA x C57Bl female mice. The mice were superovulated with pregnant
mare's serum gonadotrophin and human chorionic gonadotrophin and mated with CBA x
C57Bl males. The pronucleate ova were randomly divided between culture media with
the addition of commercially available ultrasound covers and sonographic gels in
different concentrations. As controls and potential alternatives, plastic
polyethylene bags and paraffin oil were tested simultaneously. Embryo-toxicity
was assessed by documenting cleavage capacity, blastocyst formation and embryo
degeneration in vitro. Exposure of culture medium to the ultrasound covers and
sonographic gels tested resulted in a severely reduced cleavage capacity, a high
incidence of embryo degeneration and absent or impaired blastocyst formation.
This toxic effect could be reduced by high dilutions in vitro. In contrast,
plastic polyethylene bags and paraffin oil had no influence on in-vitro
development of mouse ova. We conclude that commercially available ultrasound
latex covers and sonographic gels are toxic for mouse embryos and can potentially
influence embryonic development during infertility treatment. It is safer to
perform vaginal ultrasonic measurements using non-toxic paraffin oil (as contact
fluid) and plastic polyethylene bags (as ultrasonic cover).
PMID- 9756304
TI - Preimplantation genetic diagnosis principles and ethics.
AB - Preimplantation genetic diagnosis (PGD) followed by implantation of unaffected
embryos offers high-risk couples the option to decrease the risk of genetic
disease in their offspring without the dilemma of a prenatal diagnosis that may
be followed by a termination of pregnancy. Polar body, blastomere and blastocyst
biopsies are currently being performed, whereas the two major technologies used
for single-cell genetic analysis involve the polymerase chain reaction and
fluorescence in-situ hybridization. PGD, similar to other prenatal diagnosis
methods, raises many ethical and legal dilemmas. The high cost of practice and
the low pregnancy rate achieved are still considered the major drawbacks of this
new procedure.
PMID- 9756305
TI - Expression of class I human leukocyte antigen (HLA) and beta2-microglobulin is
associated with decidualization of human endometrial stromal cells.
AB - Human leukocyte antigen (HLA) class I molecules play a central role in the immune
system through either presentation of endogenous antigen and activation of T
lymphocytes or functional emergence of natural killer (NK) cells. Various types
of immune cells are present in the human endometrium and are believed to be
involved in reproductive function and/or immunological reaction. However, little
is known about the expression status and function of HLA class I molecules in the
human endometrium. We therefore examined mRNA expression of HLA class I. In
addition, we analysed gene expression and localization of beta2-microglobulin
(beta2-MG), which is the non-variant chain of all HLA class I molecules. Compared
with non-decidualized tissues, mRNA expression of both HLA class I and beta2-MG
was significantly higher in decidualized endometria in the late secretory phase,
under progestin treatment and during early pregnancy. Immunohistochemical studies
revealed that beta2-MG was localized in decidualized endometrial stromal cells,
indicating that the distribution of beta2-MG is topologically correlated with
that of CD56bright+ NK cells. In-vitro culture of human endometrial stromal cells
demonstrated that HLA class I mRNA was induced during the decidualization by
progesterone. Accordingly, the expression of HLA class I molecules is
transcriptionally activated along with decidualization of human endometrial
stromal cells, and may represent an immuno-endocrine function of the endometrium.
PMID- 9756306
TI - Relationship of the menstrual cycle pattern in 14-17 year old old adolescents
with gynaecological age, body mass index and historical parameters.
AB - In a cross-sectional population-based study the association between the menstrual
pattern in ninth grade schoolgirls and calendar age, gynaecological age, body
mass index (BMI) and historical parameters was investigated. The survey was held
in a combined urban and rural region, south of Amsterdam. A total of 2480
adolescents, mean age 15.3 +/- 0.6 (SD) years, answered a questionnaire: response
92%. The menstrual cycle patterns were categorized to regular menstrual cycles
(RMC), irregular menstrual cycles (IMC), oligomenorrhoea, polymenorrhoea, pre
menarche, <6 months after menarche, and oral contraceptive use. Gynaecological
age was strongly associated with the prevalence of IMC but only weakly with the
prevalence of oligomenorrhoea. In a logistic regression analysis gynaecological
age, subjective acne and intellectual performance were independently associated
with oligomenorrhoea. Gynaecological age, low BMI, chronic non-specific lung
disease (CNSLD) or allergic disease, stress and strain, weight loss of >5 kg were
independently associated with IMC. More than 8 h sports per week was associated
with not having experienced menarche in the ninth grade but not with menstrual
cycle disturbances. The association between CNSLD or allergic disease and IMC has
not previously been described. The associations between weight loss, low body
weight, stress, physical exercise or signs of hyperandrogenism and menstrual
cycle patterns in adolescents are weak when studied on a population basis. The
value of these parameters to explain abnormal menstrual cycle patterns is
limited.
PMID- 9756307
TI - A prospective randomized controlled study comparing the morphological and
biochemical responses of the endometrium to two different forms of 'period-free'
hormone replacement therapy.
AB - Thirty postmenopausal women were randomized to receive either continuous combined
(cc) 2 mg oestradiol valerate and 0.7 mg norethisterone acetate hormone
replacement therapy (HRT) daily (15 women) or tibolone 2.5 mg daily (15 women)
and were monitored to determine the relationship between the two biochemical
markers placental protein 14 (PP14) and the glycoprotein CA125, endometrial
histology and occurrence of irregular bleeding after 12 months of treatment. The
concentrations of PP14 and CA125 in plasma and uterine flushings before and after
therapy were measured and their concentrations were associated with the histology
of endometrial biopsies obtained on the same day as venesection and endometrial
flushing. The levels of PP14 in uterine flushings were significantly increased
after the administration of both types of HRT (P < 0.05 for tibolone and P <
0.001 for ccHRT). However, the concentrations of PP14 found in flushings after
ccHRT were considerably greater than those found in flushings after tibolone;
levels were increased about 150-fold by ccHRT and 6-fold by tibolone (P < 0.001).
Plasma concentration of PP14 after both types of HRT were also significantly
raised to a similar degree (P < 0.01). In contrast, the concentration of plasma
and uterine CA125 were unchanged by either treatment. Histological analysis of
the endometrium from women after 12 months of HRT treatment showed that 86% (6/7)
of women on ccHRT had secretory activity as compared to 44% (4/9) women on
tibolone (P < 0.05). Women with higher post-HRT uterine PP14 concentration were
more likely to have irregular bleeding (P < 0.05). Our studies have shown that
endometrial PP14 but not CA125 concentrations are raised to a significant degree
by two different forms of period-free HRT regimens. Increased PP14 concentrations
in uterine flushing may suggest endometrial stimulation of some form and predict
the predilection to irregular bleeding. Thus uterine PP14 concentrations may be
used to monitor endometrial responses in women on HRT.
PMID- 9756308
TI - Results and role of rectal endoscopic ultrasonography for patients with deep
pelvic endometriosis.
AB - The objective of this work was to assess the advantages and the role of rectal
endoscopic ultrasonography (EUS) when establishing evidence of infiltration of
the rectal wall in patients with proven deep pelvic endometriosis. To this end we
performed a retrospective study between July 1993 and December 1996 of a
continuous series of 38 patients who presented with deep pelvic endometriosis
which was confirmed histologically. The EUS results were considered normal in
nine cases (23.7%). In 12 cases (31.6%) EUS revealed an image compatible with
infiltration of the uterosacral ligaments and/or the rectovaginal septum without
any associated bowel infiltration. In 17 cases (44.7%) EUS revealed an image
compatible with deep infiltration of the intestinal wall. Sixteen of these 17
patients underwent laparotomy with bowel resection. The histological results
confirmed in each of these 16 patients (100%) that there was deep infiltration of
the intestinal wall by endometriotic lesions. The seventeenth patient refused
such major surgery by laparotomy, and underwent partial laparoscopy due to the
risk of bowel injury. For the 21 patients with no EUS evidence of rectal
infiltration complete laparoscopic surgical exeresis was achieved in every case
(100%) without broaching the intestinal wall. These preliminary results enable us
to state that EUS, which is a simple and non-invasive technique, provides a
reliable indication as to the presence of deep bowel infiltration in patients
with retroperitoneal endometriotic lesions. EUS used pre-operatively enables
patients to be selected for treatment via laparotomy or by laparoscopic surgery.
PMID- 9756309
TI - Surgical treatment of recurrent endometriosis: laparotomy versus laparoscopy.
AB - The objective of this study was to clarify which is the better surgical
conservative treatment for recurrent endometriosis. We compared two consecutive
surgical series at a tertiary care centre for the cure of endometriosis. The
patients were 81 women with recurrent endometriosis, 41 reoperated at laparotomy
from 1986 to 1991 and 40 reoperated at laparoscopy from 1992 to 1996. Follow-up
after the second operation included clinical and ultrasound examinations
performed at least once a year to evaluate the recovery of fertility and the
reappearance of symptoms and signs of the disease. The cumulative probability of
recurrence of dysmenorrhoea (34 and 43 respectively), and the frequency of
recurrence of pelvic pain and dyspareunia and of clinical findings suggestive of
the disease were not significantly different in the two groups. The rate of
recurrence of dyspareunia was higher in the patients operated at laparotomy as
was the number requiring a third operation. However, this could be due to the
longer follow-up of this group. No significant difference was observed between
the cumulative pregnancy rates at 24 months in the two groups (45 in the
laparotomy and 54 in the laparoscopy group). We conclude that operative
laparoscopy seems as efficacious as conservative surgery at laparotomy in the
treatment of recurrent endometriosis.
PMID- 9756310
TI - Adhesion of human endometrium to the epithelial lining and extracellular matrix
of amnion in vitro: an electron microscopic study.
AB - One of the first steps in the pathogenesis of endometriosis is the attachment of
the endometrium to the peritoneal lining. Since the peritoneum is extremely
fragile and hard to obtain, amnion has been used as an in-vitro model to study
adhesion. Scanning and transmission electron microscopy was applied to evaluate
the adhesion of endometrial cells isolated in the proliferative and secretory
phases of the menstrual cycle. Endometrial fragments obtained in either phase of
the cycle were able to adhere to the extracellular matrix of the amnion.
Fragments from proliferative phase endometrium showed active spreading and growth
over the matrix surface, whereas fragments from secretory phase endometrium did
not. Fragments from proliferative as well as secretory phase endometrium were
able to adhere to the epithelial side of the amnion, but only at locations where
the amniotic epithelium was damaged or partly absent. These observations indicate
that the basement membrane and extracellular matrix provide a suitable substrate
for endometrial cell attachment and growth and that endometrial cell adhesion
occurs preferentially to subepithelial structures, whereas an intact epithelium
prevents the adhesion of endometrial fragments to the amnion.
PMID- 9756311
TI - The effect of dexamethasone administration at different stages of gestation on
maternal plasma steroid concentrations in the baboon (Papio cynocephalus).
AB - Dexamethasone administration at different stages of gestation in the baboon was
studied for its effect on maternal steroid hormone concentrations. Dexamethasone
(2 mg i.m. at 12 h intervals for three doses) was administered at early (days 37
39), mid (days 76-85) or late (days 112-123) gestation and morning blood samples
were collected before, during and after dexamethasone suppression for 6
consecutive days. Dexamethasone treatment, at all stages of pregnancy, resulted
in a significant decline in maternal serum cortisol concentrations, which rapidly
return to normal concentrations after treatment. Progesterone concentrations were
not affected by dexamethasone at any stage of gestation. Serum concentrations of
oestradiol, testosterone and androstenedione were unchanged following
dexamethasone administration in early pregnancy. A trend toward lower serum
oestradiol was observed following dexamethasone administration in both mid and
late gestation, but this was not significant. Both testosterone and
androstenedione were significantly decreased following dexamethasone in both mid
and late pregnancy and recovered to pretreatment concentrations within a few days
after cessation of treatment. These results confirm other studies which
demonstrate that adrenal precursors (maternal or fetal) are a major contributor
to maternal serum concentrations of oestradiol. They also demonstrate that these
adrenal precursors increase serum concentrations of testosterone and
androstenedione in the pregnant baboon. Since these changes are only evident
after that time (>40 days) when the fetal adrenal is steroidogenically competent,
a role for fetal adrenal involvement in maternal serum androgen concentrations is
suggested.
PMID- 9756312
TI - Coffee consumption and risk of hospitalized miscarriage before 12 weeks of
gestation.
AB - In order to analyse the association between drinking coffee in pregnancy and risk
of spontaneous abortion, a case-controlled study was conducted in Milan, Northern
Italy. Cases were 782 women with spontaneous abortion within the 12th week of
gestation. The control group was recruited from women who gave birth at term (>
37 weeks gestation) to healthy infants on randomly selected days at the same
hospitals where cases had been identified: 1543 controls were interviewed. A
total of 561 (72%) cases of spontaneous abortion and 877 (57%) controls reported
coffee drinking during the first trimester of the index pregnancy. The
corresponding multivariate odds ratios of spontaneous abortion, in comparison
with non-drinkers, were 1.2, 1.8 and 4.0, respectively, for drinkers of 1, 2 or
3, and 4 or more cups of coffee per day. No relationship emerged between maternal
decaffeinated coffee, tea and cola drinking in pregnancy, as well as paternal
coffee consumption, and risk of spontaneous abortion. With regard to duration in
years of coffee drinking, the estimated multivariate odds ratios of spontaneous
abortion were, in comparison with non-coffee drinkers, 1.1 (95% confidence
interval (CI) 0.9-1.4) and 1.9 (95% CI 1.5-2.6) for women reporting a duration of
coffee consumption < or = 10 or > 10 years. In conclusion, coffee drinking early
in pregnancy was associated with an increased risk of abortion. This has
biological implications, but epidemiological inference on the causality is
difficult and still open to debate.
PMID- 9756313
TI - Differential concentrations of monocyte chemotactic protein-1 and interleukin-8
within the fluid compartments present during the first trimester of pregnancy.
AB - Monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8) are important
chemokines which effect the chemotaxis of monocytes and neutrophils,
respectively. There is increasing evidence that such chemokines play an integral
role in the control and maintenance of a normal pregnancy from implantation to
parturition. However, little is known about the sites of secretion and function
of MCP-1 and IL-8 in particular with respect to establishment of the placenta and
membranes during first trimester. The aim of this study was therefore to
investigate the concentrations and localization of MCP-1 and IL-8 in amniotic
fluid and extra-embryonic coelomic fluid (EECF) collected by ultrasound-guided
needle aspiration and maternal serum during the first trimester of pregnancy.
Using specific enzyme-linked immunosorbent assays, MCP-1 was present at high
concentrations in the EECF, significantly higher than those in amniotic fluid and
maternal serum. IL-8 was also present predominantly in the EECF with
concentrations being significantly higher than the low values detected in
maternal serum and the very low amounts found in amniotic fluid. This strict
compartmentalization of these cytokines in the fluid compartments of early
pregnancy may be important for establishment and development of a viable
pregnancy.
PMID- 9756314
TI - Stress and anxiety do not result in pregnancy wastage.
AB - The association between stress and reproductive outcome is unclear. In-vitro
fertilization (IVF) is psychologically stressful and has been shown to alter
psychological markers such as cortisol, prolactin and progesterone. This study
was designed to assess prospectively psychological and physiological markers of
stress and to determine if they are related to pregnancy outcome. Forty patients
were recruited from Northwestern Medical Faculty Foundation (Chicago, Illinois,
USA) having obtained an initial positive beta-human chorionic gonadotrophin (HCG)
concentration 13 days after IVF with uterine embryo transfer. Patients underwent
psychological and hormonal testing on three separate occasions (13, 20 and 27
days after embryo transfer) early in pregnancy. All subjects were followed to
delivery. An adverse outcome was defined as a miscarriage before or after cardiac
activity (including vanishing twin) or a loss before 20 weeks gestation. There
was no difference in age, duration of infertility, diagnosis between patients
experiencing an adverse pregnancy outcome (n = 18) and those that did not (n =
22). All patients were found to have high stress levels although this did not
differentiate between groups of patients. There was no difference in hormonal
markers of stress between patients. In conclusion, there is little association
between psychological scores and physiological stress hormone concentrations.
Also, it does not appear that high levels of anxiety and stress result in an
adverse pregnancy outcome.
PMID- 9756315
TI - Selective termination and elective reduction in twin pregnancies: 10 years
experience at a single centre.
AB - Selective termination is employed in multifetal pregnancies, in the presence of
an abnormal fetus, in order to improve the prognosis of the normal fetuses. The
term elective reduction is used to describe reduction in twin pregnancies for
maternal medical conditions, psychological, or socioeconomic reasons. The purpose
of this study was to evaluate the factors that influence outcome in such
pregnancies. Eighty-two twin pregnancies underwent selective termination (n = 59)
or elective reduction (n = 23) over a 10-year period. Early procedures, performed
< or = 14 weeks (n = 31), had a pregnancy loss of 9.7% and a mean procedure-to
loss interval of 4.1 +/- 2.8 weeks; mean birthweight was 3299 +/- 395 g in
survivors, with a mean gestational age at delivery of 38.4 +/- 2.3 weeks. In
comparison, procedures performed > 14 weeks (n = 51) had a pregnancy loss of
7.8%, with a procedure-to-loss interval of 1.2 +/- 0.6 weeks. Mean birthweight
was 2577 +/- 999 g, with a mean gestational age at delivery of 35.7 +/- 5 weeks.
In conclusion, outcomes were more favourable among patients who underwent a first
trimester procedure. The slight increase in pregnancy loss may be attributed to a
higher than expected rate of spontaneous abortions in the first trimester, as
manifested by the higher procedure-to-loss interval after a first trimester
procedure. These facts underscore the importance of early detection of fetal
abnormalities in twin pregnancies by ultrasonography and chorionic villus
sampling.
PMID- 9756316
TI - Evaluation of serum inhibin A as a surveillance marker after conservative
management of tubal pregnancy.
AB - Tubal pregnancy is now commonly managed by laparoscopic salpingostomy or systemic
methotrexate. A disadvantage of such conservative management is the need for
appropriate follow-up, with serial measurement of serum concentrations of human
chorionic gonadotrophin (HCG), to exclude persistent ectopic pregnancy (PEP).
Concentrations of inhibin A, also a placental product, are significantly
increased during pregnancy and the half-life of inhibin A is significantly
shorter than that of HCG. To assess the suitability of inhibin A as a marker of
PEP, we studied 16 women who had undergone surgery for a tubal pregnancy,
measuring HCG and inhibin during follow-up. The mean +/- SEM time taken to
achieve non-pregnant concentrations of inhibin A was significantly shorter than
for HCG (4.2 +/- 0.8 days versus 21.6 +/- 4.4 days respectively; P < 0.001
Wilcoxon signed rank test). However, in all women the inhibin A concentration
increased rapidly after reaching a nadir, reflecting the return of ovarian
function, complicating the interpretation of results. In four women inhibin A was
almost undetectable preoperatively, while the corresponding HCG concentration was
high. These data suggest that inhibin A will not be a useful marker for PEP but
that it may provide a more accurate preoperative assessment of trophoblast
viability than HCG, thereby improving management.
PMID- 9756317
TI - Shedding of tumour necrosis factor receptors from purified villous term
trophoblasts and cytotrophoblastic BeWo cells.
AB - Within the placenta tumour necrosis factor-alpha (TNF-alpha) and its surface
receptors TNF-RI and -RII have been detected on villous cyto- and
syncytiotrophoblast and a role in trophoblast function/differentiation and
turnover has been suggested. Here, we show for the first time that purified
villous trophoblasts and cytotrophoblastic BeWo cells extensively shed TNF
receptors, suggesting that release of these soluble proteins is an inherent
property of trophoblasts. In supernatants of purified villous trophoblasts, TNF
RI and -RII increased from undetectable levels to 307 pg/ml and 484 pg/ml,
respectively, within 12 h of cultivation. In BeWo cells, 26 pg/10(5) cells and 54
pg/10(5) cells of soluble TNF-RI and -RII, respectively, accumulated within 24 h
of culturing. While forskolin did not alter TNF-RI expression, TNF-RII mRNA,
protein and secretion were selectively up-regulated in these choriocarcinoma
cells suggesting that elevation of cAMP levels could modulate cellular events by
TNF-RII-mediated signal transduction. Interleukin-1, which greatly enhances TNF
alpha release from trophoblast cells, did not alter shedding of both receptors
from villous trophoblasts or BeWo cells. Secretion of TNF receptors from the
trophoblast may explain the high levels of soluble TNF-binding proteins in urine
of pregnant women and could play a role in regulating TNF-alpha activity in the
placental villus or protection against the cytotoxic effects of the cytokine.
PMID- 9756318
TI - Placental transfer of fentanyl in early human pregnancy.
AB - To investigate the transfer of fentanyl across the early human placenta, we have
collected samples of maternal blood and fetal fluids and/or blood,
simultaneously, between 5 and 22 min following an intravenous bolus of fentanyl
(1.5 microg/kg) to the mother. The pregnancies were between 6 and 16 weeks of
gestation and scheduled for elective termination of pregnancy under general
anaesthesia. Total fentanyl concentration was determined by radioimmunoassay in
11 pairs of first trimester maternal serum and fetal coelomic fluid samples, 14
pairs of maternal serum and amniotic fluid samples, seven series of first
trimester maternal serum and coelomic and amniotic fluid samples, and 10 series
of early second trimester maternal and fetal sera and amniotic fluid samples.
Fentanyl was not detected in coelomic fluid samples at any gestational age and in
amniotic fluid samples collected after 12 weeks of gestation. Measurable
concentrations of fentanyl were found in maternal serum collected within 15 min
after the initial bolus and in fetal serum collected between 10 and 12 min later.
These findings indicate that fentanyl is transferred across the early placenta
into the amniotic cavity and fetal blood circulation but not into the exocoelomic
cavity. The distribution of this molecule inside the early gestational sac is
probably influenced by the increased binding by maternal and fetal sera, its
short half-life of distribution and the specific biology of the fetal fluid
formation and composition.
PMID- 9756320
TI - Male to female ratio in newborns of grand grand multiparous women.
AB - The male to female ratio in newborns of grand grand multiparous women was
evaluated in 569 Jewish Orthodox women and 28 Muslim women. A total of 882 babies
was born on the > or = 10th delivery; 460 (52.2%) were males and 422 (47.8%) were
females (sex ratio = 1.06). Newborn sex ratio did not significantly change with
respect to birth order or maternal age. It is suggested that parity and
increasing maternal age do not affect the sex ratio of newborns and that ethnic
and environmental variables may play a role in the deviations in offspring sex
ratio observed among different populations.
PMID- 9756319
TI - Decline in sex ratio at birth after Kobe earthquake.
AB - We investigated the possible association between the Kobe earthquake (January
1995) and the sex ratio among live-born infants after the catastrophe. A
significant decline in the sex ratio (0.501) of Hyogo Prefecture in October 1995
was observed 9 months after the Kobe earthquake as compared with an expected
value of 0.516 in the period from January 1993 to January 1996 (P = 0.04; one
tailed). Simultaneously, a reduction in fertility of approximately 6% was also
observed, compared with the month of October 2 years previously. Thus, the acute
stress resulting from a great natural catastrophe can be a cause of a low sex
ratio at birth 9 months later.
PMID- 9756321
TI - Hormones and cardiovascular diseases: oral contraceptives and hormonal
replacement therapy: differential effects on coronary heart disease, deep venous
thrombosis and stroke. The ESHRE Capri Workshop Group.
PMID- 9756322
TI - Motile organisms in the epididymis?
PMID- 9756324
TI - Secular movements in dizygotic twinning rates and in sperm counts.
PMID- 9756325
TI - Biased postural vertical in humans with hemispheric cerebral lesions.
AB - This study was aimed at demonstrating the existence of a biased postural vertical
in humans with a recent cerebral lesion. The postural vertical of patients and
controls was analysed comparatively using a self-regulated balancing task,
performed in sitting posture. Patients displayed a quite constant (19/22)
contralesional tilt of the postural vertical (mean -2.6 degrees), varying with
the severity of their spatial neglect and hemianaethesia. Eight of them showed a
pathological contralesional bias (mean -5.5 degrees) as compared to normals. This
result indicates an asymmetric process of somatic graviceptive information due to
some cerebral lesions. When patients were subjected to a transcutaneous
electrical stimulation applied onto the contralesional side of the neck, body
verticality was especially improved in those who showed a pathological bias in
the postural vertical. This effect could thus be due to a reduced distortion in
the egocentric co-ordinate system for spatial information processing.
PMID- 9756326
TI - Modality-specific subregions in human inferior parietal lobule: a
magnetoencephalographic study during cognitive tasks.
AB - The inferior parietal lobule (IPL) has been considered to be a multimodal sensory
association area. Both event-related potentials and magnetic responses have
examined the relationships between IPL and cognitive processing. However, there
have been no studies clarifying the functional subregions in IPL. We studied the
event-related magnetic response during conventional auditory and visual oddball
paradigms. We were able to distinguish non-invasively modality-specific
subregions in IPL. The subregion in IPL activated by auditory target stimuli was
located more anterior and superior than that responding to visual target stimuli
on each hemisphere. The data suggests that modality-specific subregions in the
IPL are differentially activated by auditory or visual stimuli.
PMID- 9756327
TI - Cholinergic lesions of the rat brain by ibotenic acid and 192 IgG-saporin:
effects on somatostatin, substance P and neuropeptide Y levels in the cerebral
cortex and the hippocampus.
AB - Impairment of the basal forebrain cholinergic system is an important change in
the brains of Alzheimer's disease patients. Various neurotoxins have been used to
achieve this in animal models. In this study the effects of chemical lesions by
ibotenic acid (IBO), a glutamate analogue and by 192 IgG-saporin, a highly
specific immunotoxin against cholinergic neurons, were investigated. The toxins
were delivered stereotaxically into the brains of young Sprague-Dawley rats which
were later sacrificed by decapitation. Choline acetyltransferase (ChAT) activity
was measured by radioenzymatic assay and substance P (SP), neuropeptide Y (NPY)
and somatostatin (SOM) levels by radioimmunoassay. Decreased ChAT and SOM levels
were observed in the cortex and the hippocampus in both experiments. Cortical SP
levels were increased after IBO lesions but were unaffected after 192 IgG-saporin
lesions. NPY levels remained unchanged in both experiments. The results indicate
that there were specific changes in neuropeptide contents in the cortex and
hippocampus in response to cholinergic damage in the rat brain.
PMID- 9756329
TI - Minimum light intensity required to suppress nocturnal melatonin concentration in
human saliva.
AB - We set out to determine the minimum intensity of light able to suppress nocturnal
melatonin levels as measured in normal human saliva. Five healthy male volunteers
were exposed to light at different intensities (<10, 500, 1000, 2500, and 5000
lux) in a repeated measure design. Suppression of melatonin was dependent on both
light intensity and duration of light exposure. Minimum intensities of light
suppressing nocturnal melatonin levels were calculated as 393, 366, 339, and 285
lux for exposure durations of 30, 60, 90, and 120 min, respectively. Minimum
effective intensity and duration of light exposure showed a linear inverse
relationship. These results suggest that less intensity of light than previously
reported suffices to suppress melatonin in humans, and that caution is required
in interpreting studies using long exposure to dim light as a background
condition.
PMID- 9756328
TI - Glial cell line-derived neurotrophic factor protects against 1-methyl-4-phenyl
1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in C57BL/6 mice.
AB - To mimic chronic exposure to neurotoxins in inducing dopaminergic cell damage,
multiple doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were
injected in C57BL/6 mice. Effects of pre- and post-treatment with the glial cell
line-derived neurotrophic factor (GDNF) by injections into the striatum were
investigated. GDNF exerts protective and reverse effects on the dopaminergic
damage, supporting the potential application of GDNF in prevention and treatment
of Parkinson's disease.
PMID- 9756330
TI - The -491A/T apolipoprotein E promoter polymorphism association with Alzheimer's
disease: independent risk and linkage disequilibrium with the known APOE
polymorphism.
AB - The epsilon4 allele of the apolipoprotein E gene (APOE) has repeatedly been
associated with increased risk for Alzheimer's disease (AD). Bullido and
colleagues recently identified a polymorphism in the promoter region of the APOE
gene (-491A/T) and found that -491A homozygosity predicted AD independently of
APOE epsilon4. Since the -491A/T polymorphism and the known APOE polymorphism
must be in tight linkage disequilibrium, and the later polymorphism is know to be
associated with the disease, we wished to determine to what extent this linkage
disequilibrium explained the -491A/T polymorphism association with Alzheimer's
disease. We genotyped a community-based control sample (n = 132) and a clinic
based Alzheimer's disease sample (n = 190) for the known APOE and -491A/T
polymorphisms, and find that, while the -491A/T polymorphism confers some
independent risk for AD, linkage disequilibrium between the known APOE and
491A/T polymorphic sites explains most of the -491A association. Furthermore,
when considering the known APOE and -491A/T polymorphisms alone, APOE epsilon4
status is the best predictor of the disease.
PMID- 9756331
TI - Possible neural substrates of beer-craving in rats.
AB - Rats voluntarily consumed beer in a distinctive environment during 30 min daily
sessions over 21 days, ingesting a daily average of 0.96 g/kg of ethanol. On a
final test day, rats in a 'craving' condition were denied access to the beer in
the drinking environment. The expression of c-fos in the brain of 'craving' rats
was compared with that in rats given free access on the test day ('beer'
condition), and to rats which had been repeatedly placed in the drinking
environment without ever having access to beer ('control' condition). Rats in the
'craving' condition showed significantly higher c-fos counts than either the
'beer' or 'control' rats in a variety of corticolimbic and brainstem structures,
indicating that activation of these regions occurs when a desirable alcoholic
beverage is expected but not received.
PMID- 9756332
TI - Ciguatoxin (CTX-1) modulates single tetrodotoxin-sensitive sodium channels in rat
parasympathetic neurones.
AB - The actions of the marine neurotoxin, ciguatoxin-1 (CTX-1), were investigated in
isolated parasympathetic neurones from neonatal rat intracardiac ganglia using
patch-clamp recording techniques. Under current clamp conditions, bath
application of 1-10 nM CTX-1 caused gradual membrane depolarization and tonic
action potential firing. Action potential firing ceased with depolarization
beyond approximately -35 mV and application of 300 nM tetrodotoxin (TTX)
repolarized the cell to its control resting potential. In cell-attached membrane
patches, 1-10 nM CTX-1 in the patch pipette markedly increased the open
probability of single TTX-sensitive Na+ channels in response to depolarizing
voltage steps but did not alter the unitary conductance (10 pS) or reversal
potential. Under steady-state conditions, CTX-1 caused spontaneous opening of
single Na+ channels which did not inactivate at hyperpolarized membrane
potentials. CTX-1 increases neuronal excitability by shifting the voltage of
activation of TTX-sensitive Na+ channels to more negative potentials.
PMID- 9756333
TI - Glial cell line-derived neurotrophic factor and nerve growth factor receptor
mRNAs are expressed in distinct subgroups of dorsal root ganglion neurons and are
differentially regulated by peripheral axotomy in the rat.
AB - We examined the colocalization of glial cell line-derived neurotrophic factor
(GDNF) and nerve growth factor (NGF) receptor genes in rat dorsal root ganglion
(DRG) neurons, and investigated the changes of the gene expression following
sciatic nerve transection using in situ hybridization histochemistry. About 60%
and 35% of the lumbar DRG neurons expressed c-ret and trkA, proto-oncogenes of
the functional receptors for GDNF and NGF, respectively. Of the DRG neurons,
however, only 9% was positive for both genes. A marked enhancement of the gene
expression for GDNF receptor alpha (GDNFR alpha), which is a component of GDNF
receptor, was observed in DRG neurons after sciatic nerve transection, but the
percentage of c-ret mRNA-expressing neurons was not changed. The trkA mRNA
expressing neurons were decreased in number. These findings suggest that GDNF and
NGF support distinct subgroups in intact DRG neurons, and that these receptor
genes are differentially regulated when a peripheral nerve is injured.
PMID- 9756334
TI - Overexpression of glucose transporter protein 5 in sciatic nerve of
streptozotocin-induced diabetic rats.
AB - The localization and the expression level of glucose transporter 5 (GLUT 5),
detected by immunohistochemical and Western blot analyses, and motor nerve
conduction velocity (MNCV) in normal and streptozotocin (STZ)-induced diabetic
rats were compared. The effects of insulin and recombinant human insulin-like
growth factor-I (rhIGF-I) were also investigated. GLUT 5 was localized in Schwann
cells and axons. GLUT 5 was overexpressed in both sites 5 weeks after STZ
injection and MNCV was decreased significantly in STZ-induced diabetic rats as
compared with normal rats. These deviations returned to normal rat level after 2
weeks medication with insulin or rhIGF-I, started 3 weeks after STZ injection.
These results suggest that overexpression of GLUT 5 may be a trigger for diabetic
neuropathy.
PMID- 9756335
TI - Right auditory cortex lesion in Mongolian gerbils impairs discrimination of
rising and falling frequency-modulated tones.
AB - Mongolian gerbils (Meriones unguiculatus) were trained in a shuttle box to
discriminate the direction in frequency-modulated tones (FM). Whereas control
animals easily acquired FM discrimination, animals with auditory cortex lesion on
the right side showed considerable difficulties in learning this task. The
discrimination performance of gerbils with left auditory cortex lesion, however,
was not different from controls. This study, suggesting that the right auditory
cortex plays a dominant role in FM discrimination learning in gerbils, describes
a useful animal model for investigation of the basic mechanisms underlying
hemispheric asymmetries in auditory perception.
PMID- 9756336
TI - Induction of plasminogen in rat hippocampal pyramidal neurons by kainic acid.
AB - Tissue plasminogen activator (tPA) is used to treat acute stroke, but tPA- and
plasminogen-gene-deficient mice exhibit resistance to neurodegeneration. Thus, it
is unclear whether the tPA-plasminogen system, an extracellular proteolytic
cascade plays a helpful or harmful role, and whether plasminogen is induced by
neurodegeneration. In the CA3, kainic acid (KA)-injection caused neuronal damage
after 6 h, and almost all of the neurons were lost after 7 days. Plasminogen mRNA
was strongly induced 6 h after injection, then gradually decreased, and was very
weak at 2 days after injection. Plasminogen protein was expressed after 6 h and
localized in abnormally shaped neurons. The in vivo expression of plasminogen was
synchronous with morphological changes in neurons. These results suggest that the
expression of plasminogen induced by KA-injection may disrupt of neuron
extracellular matrix interaction and thereby contribute to cell death in neurons
in the hippocampus.
PMID- 9756337
TI - Dystrophin deficient myotubes undergo apoptosis in mouse primary muscle cell
culture after DNA damage.
AB - Apoptosis has been demonstrated to occur in differentiated myocardial muscle,
neonatal skeletal muscle and skeletal myoblasts in response to injury. In this
report, we studied differentiated normal and dystrophin deficient murine skeletal
muscle cell cultures that have been injured by a pulse of cis-platinum (2 h).
Forty-eight hours after DNA damage, dystrophin positive myotubes appeared almost
normal though some myoblasts showed DNA fragmentation. On the other hand,
dystrophin deficient myotubes presented progressive degeneration via apoptosis
detected either by TUNEL or by nuclear morphology. Degeneration of mdx muscle
fibers was confirmed by counting both the number of myotubes observed by contrast
phase microscopy and myonuclei viewed by immunoreaction for MyoD. A 6-fold
decrease in the number of muscle cells was observed in the dystrophin-deficient
cell culture compared to the parental culture (P < 0.001). Direct evidence of
degenerating myotubes displaying MyoD- and TUNEL-positive nuclei was obtained.
Like myoblasts, differentiated dystrophin deficient myotubes were able to
degenerate via apoptosis, showing that mature dystrophin deficient cells are
fragile and undergo apoptosis when subjected to a mild injury which would
normally be repaired in parental cells.
PMID- 9756338
TI - Intracellular calcium and arachidonic acid increase SNAP-25 expression in
cultured rat hippocampal explants, but not in cultured rat cerebellar explants.
AB - The effects of the increase of intracellular calcium, induced by membrane
depolarization with 50 mM KCl, and arachidonic acid (AA) on the expression of 25
kD synaptosomal-associated protein (SNAP-25) were studied in cultured rat
hippocampal and cerebellar explants, and PC12 rat pheochromocytoma cells, using
immunoblot analysis. Incubation periods of 24 h and 48 h in 50 mM KCl increased
SNAP-25 levels in hippocampal explants and PC12 cells, but not on cerebellar
explants. Otherwise, a 24 h incubation with 10 microM AA increased SNAP-25
expression only in hippocampal explants, although 100 ng/ml phorbol 12-myristate
13-acetate (PMA) did not have effect. These results indicate that intracellular
calcium and AA can modulate the expression of SNAP-25, depending on the origin of
the tissue.
PMID- 9756339
TI - Expression and coupling of somatostatin receptors in rat adrenal (PC12) and
pituitary (GC) cell lines.
AB - Somatostatin (somatotropin release-inhibiting factor, SRIF) interacts with G
protein coupled receptors (sst) designated sst1 through sst5. In PC12 and GC
cells, SRIF binding sites were identified and mRNA receptor expression was
evaluated. SRIF binding sites were expressed at a much lower density in PC12 (Kd
= 21.2 +/- 3.9 nM; Bmax = 31 +/- 8 fmol/mg protein) than in GC cells (Kd = 6.4 +/
1.6 nM; Bmax = 643 +/- 29 fmol/mg protein). sst3 receptor mRNA (81% of the
total) was mainly expressed in PC12 cells, while sst1/2 receptor mRNAs were
mostly expressed in GC cells (64 and 29%, respectively). In PC12 cells, adenylyl
cyclase (AC) activity was unaffected by SRIF-14 (binding all SRIF receptors),
octreotide (specific for sst2/3/5 receptors), BIM 23056 (binding sst3/5
receptors) or CH275 (specific for sst1 receptors), 1 microM each. In GC cells,
SRIF-14 or octreotide, but not the two other peptides, significantly inhibited AC
activity.
PMID- 9756340
TI - The vagal origin of preganglionic fibers containing nitric oxide synthase in the
guinea-pig heart.
AB - The origin of nerve fibers projecting to the guinea pig heart that contain nitric
oxide synthase (NOS) were studied by unilateral cervical vagotomy. Three kinds of
NOS-immunoreactive (NOS-ir) nerve fibers are distributed in the control guinea
pig heart: the sparse network covering the right atrium, the basket-like endings
around intracardiac neuronal cell bodies in the small ganglia located in the left
atrium and the interatrial septum, and the axons situated in the septal region.
The sparse network in the right atrium did not change after vagotomy of right or
left side. In the whole mount preparations of right atrium, we often traced
labeled axons from the somata to join the network covering the right atrium.
Therefore, most of this network of labeled fibers must be of intrinsic origin.
Because the basket-like endings around neuronal cell bodies in the ganglia in the
left atrium and the septum disappeared completely after vagotomy of left side, we
conclude that they are parasympathetic preganglionic fibers originating from the
left vagus nerve. NOS-ir cell bodies and the positive fibers in the
atrioventricular nodal region survived after vagotomy. All of such nerve fibers
were unmyelinated axons. Therefore, they seem to be the postganglionic fibers
arising from the ganglia located in the left atrium or the septum.
PMID- 9756341
TI - Highly variable distribution of HSV-1-specific DNA in human geniculate,
vestibular and spiral ganglia.
AB - Viral reactivation in temporal ganglia is the suspected cause of Bell's palsy,
vestibular neuritis and sudden hearing loss. Since the distribution of latent
herpes simplex type 1 (HSV-1) in geniculate, vestibular and spiral ganglia of
individual human temporal bones could have implications for the explanation of
isolated as well as combined disorders of these three cranial nerves, we examined
these ganglia in 18 human temporal bones of adults by nested polymerase chain
reaction. In all of the temporal bones HSV-1 specific DNA was detected: 10/18
(56%) of the geniculate, 11/18 (61%) of the vestibular and 9/18 (50%) of the
spiral ganglia samples were positive. All combinations of positive and negative
ganglia were found in individual temporal bones at roughly equal frequencies.
These data support a viral etiology of all three conditions, especially their
occasional combinations.
PMID- 9756342
TI - The proportion of isolated rat dorsal root ganglion neurones responding to
bradykinin increases with time in culture.
AB - The proportion of isolated rodent dorsal root ganglion neurones expressing
bradykinin receptors increases transiently with time in culture. However, it has
not yet been investigated whether these receptors are functioning. Therefore the
responses of these neurones to bradykinin (1 microM) were investigated in patch
clamp experiments in the current clamp mode after 0.8 and 1.8 days under culture
conditions. The proportion of neurones responding to bradykinin was 26% (5/19) at
day 0.8 and increased to 73% (16/22) at day 1.8. The intensity of the response
was assessed by counting the number of action potentials evoked by bradykinin
within four fixed intervals of 500 ms duration during each experiment. It
increased with time in culture from an average of 8 +/- 2 (SD) at day 0.8 to 16
+/- 6 at day 1.8, respectively. These results provide evidence for the induction
of functioning bradykinin receptors in cultured dorsal root ganglion neurones
with time in culture.
PMID- 9756343
TI - Differential effects of treatment with nerve growth factor on thermal nociception
and on calcitonin gene-related peptide content of primary afferent neurons in the
rat.
AB - We have investigated the effect of repeated systemic administration of nerve
growth factor (NGF) to rats on (a) the calcitonin gene-related (CGRP) content of
primary afferent neurons and (b) the thermal nociceptive threshold in normal and
inflamed hind paws. NGF (0.1 mg/kg s.c.) was administered every other day for 7
days. After each injection of NGF there was transient thermal hyperalgesia
lasting less than 23 h. One day after the last of four NGF injections, there was
no detectable difference of the thermal nociceptive threshold between the NGF
treated and control group. NGF treatment caused, however, a significant increase
of the concentration of immunoreactive (IR) CGRP in the sciatic nerves and paw
skin while it had no significant effect on CGRP-IR in the stomach or ureter. A
separate set of experiments showed that intraplantar injection of complete
Freund's adjuvant (CFA) in NGF-treated rats caused thermal hyperalgesia and edema
that was not significantly different from values obtained in the control group.
The results suggest that prolonged treatment of rats with moderate doses of NGF
is sufficient to stimulate neuropeptide synthesis in primary afferent neurons
without causing long-lasting changes in thermal nociceptive threshold.
PMID- 9756344
TI - Differential expression of group I metabotropic glutamate receptors (mGluRs) in
the rat pheochromocytoma cell line PC12: role of nerve growth factor and ras.
AB - Glutamate treatment of PC12 cells has been shown to result in the accumulation of
intracellular inositol phosphates suggesting the presence of glutamate
metabotropic receptors (mGluRs) positively coupled to phospholipase C. The
present study examined the expression of group I mGluRs (mGluR1 and mGluR5) in
PC12 cells. Undifferentiated PC12 cells were found to express both mGluR5 mRNA
and receptor protein by reverse transcription polymerase chain reaction (RT-PCR)
and western blot techniques. However, mGluR1 mRNA was not detected in these cells
and western blot analysis showed only faint mGluR1alpha immunoreactivity
suggesting a very low level of mGluR1 expression. Nerve growth factor-induced
differentiation of PC12 cells resulted in the induction of mGluR1alpha and
mGluR1beta mRNA and mGluR1alpha protein. PC12 cells overexpressing dominant
negative ras revealed that NGF-induced mGluR1 induction, but not mGluR5
expression, is dependent on ras pathway activation in these cells. These results
suggest PC12 cells may be a useful model for investigating the regulation and
expression of group I mGluR isoforms and their role in neuronal processes in
vitro.
PMID- 9756345
TI - Pulse exposure of cultured rat neurons to aluminum-maltol affected the axonal
transport system.
AB - Although chronic aluminum neurotoxicity has been well established, the mechanism
of the toxicity has not been elucidated yet. In order to simplify the study of
the aluminum neurotoxicity, we employed the pulse exposure of cultured rat
cortical neurons to 250 microM aluminum-maltol for 1 h at the early stage (6 h
after plating), which resulted in abnormal distribution of neurofilament L (NFL)
and fast axonal transported proteins, whereas the axonal transport of tubulin,
actin, and clathrin were not impaired. Otherwise, the pulse exposure of neurons
at the late stage (4 days after plating) to the same concentration of aluminum
maltol did not affect the cell morphology and the distribution of NFL. The pulse
exposure of cultured neurons to aluminum-maltol at the early stage might affect
the axonal transport system of NFL and fast axonal transported proteins.
PMID- 9756346
TI - Heat shock protein expression protects against death following exposure to
heatstroke in rats.
AB - Rats 0, 16, or 48 h after heat shock (42 degrees C core temperature for 15 min)
or chemical stress (5 mg/kg sodium arsenite, i.p.) were exposed to a high ambient
temperature (43 degrees C) to induce heatstroke onset. The moment in which the
mean arterial pressure and cerebral blood flow began to decrease from their peak
values was taken as the onset of heatstroke. Prior heat shock or chemical stress
conferred significant protection against heatstroke-induced arterial hypotension,
cerebral ischemia, cerebral neuronal damage and death, and correlated with
expression of HSP72 in brain, heart, liver and kidney at 16 h. However, at 48 h,
when HSP72 expression returned to basal values, the above responses that occurred
after the onset of heatstroke of two groups (0 h group VS 48 h group) were
indistinguishable. The data suggest that HSP72 presence increases survival in rat
heatstroke by attenuating arterial hypotension, cerebral ischemia and neuronal
damage.
PMID- 9756347
TI - Regulation of cannabinoid and mu opioid receptors in rat lumbar spinal cord
following neonatal capsaicin treatment.
AB - In vitro receptor binding and quantitative autoradiography were used to determine
whether cannabinoid receptors in rat lumbar spinal cord are localized to the
central terminals of nociceptive primary afferents. Rats were treated as neonates
with capsaicin to destroy sensory C-fibers. The densities of cannabinoid and mu
opioid receptors in the spinal cord of the adult rats were compared with age
matched vehicle controls. Neonatal capsaicin produced a moderate but reliable
suppression (16%) of [3H]CP55,940 binding to cannabinoid receptors. By contrast,
the binding of [3H][D-Ala2-MePhe4,Gly-ol5]enkephalin (DAMGO) to mu receptors was
depleted by approximately 60% in near adjacent sections. These data suggest that
only a subpopulation of cannabinoid receptors is situated on the central
terminals of primary afferent C-fibers. The present data provide anatomical
evidence for a dissociation between cannabinoid and mu opioid modulation of
sensory transmission at the level of the primary afferent inputs to the spinal
cord.
PMID- 9756348
TI - Anti-gamma interferon can prevent the premature death of trisomy 16 mouse
cortical neurons in culture.
AB - Previous reports have indicated that human trisomy 21 and mouse trisomy 16
neurons exhibit decreased viability in culture when compared to euploid control
cultures and that trisomic cells are significantly more sensitive to the anti
cellular effects of the interferons. In the study reported here, cortical neurons
from euploid and trisomy 16 mouse fetuses were treated with either anti-gamma
interferon or non-specific IgG and neuron morphology and viability measured
photographically. The addition of anti-gamma-interferon IgG to the culture media
had no effect on euploid neurons, but significantly increased trisomy neuron
viability throughout the 5-day culture period. Assay of both DNA fragmentation
and phosphatidylserine externalization suggested that the trisomic neurons were
undergoing apoptosis at a significantly higher rate than their euploid
counterparts and that this increase in apoptosis could be almost completely
prevented by addition of either ligand purified monoclonal or ligand purified
polyclonal anti-gamma-interferon IgG. Taken together, these data suggest that
endogenous interferon plays an important role in the premature death of the
trisomy neuron.
PMID- 9756349
TI - Melatonin inhibits the increase of cyclic AMP in rat suprachiasmatic neurons
induced by vasoactive intestinal peptide.
AB - The effects of melatonin on basal and vasoactive intestinal peptide (VIP)-induced
cAMP concentration was studied in dispersed cells of the rat suprachiasmatic
nuclei (SCN). Our data indicate, that VIP induces a rapid increase of cAMP
concentration in the cells followed by a slow and prolonged increase in the
medium. The VIP-induced increase was dose-dependent in the range of 1-100 nM.
Melatonin had no effect on basal cAMP but inhibited the cAMP increase induced by
VIP in a dose-dependent manner (EC50 = 0.21 nM). Our observations indicate that
melatonin acts through the inhibition of cAMP in the SCN cells similar as shown
in other tissues.
PMID- 9756350
TI - The negative influence of endogenous opioid receptor activity on the
differentiation of the rat pheochromocytoma PC12 cells induced by nerve growth
factor.
AB - We determined the effect of naloxone and morphine on the differentiation of
pheochromocytoma cell, the PC12 cells, induced by nerve growth factor (NGF). PC12
cells were grown in medium containing NGF with or without the addition of
naloxone or morphine for up to 10-day treatments. NGF-induced morphological
differentiation of PC12 cells was manifested by an increase in the percentage of
differentiated cells and the average length of neurite per cell. Co-addition of
morphine with NGF did not affect both parameters as compared to that of NGF
alone. On the contrary, co-addition of naloxone with NGF significantly increased
the percentage of differentiated cells, but did not affect the outgrowth of
neurites. This effect of naloxone was reversed by the addition of morphine,
suggesting that naloxone produced its effect by inhibiting the endogenous
activity of opioid receptor. This study indicates a significant functional role
of opioid receptor in NGF-induced differentiation of PC12 cells.
PMID- 9756351
TI - H+-sensitivity of cultured neurons from the dorsomedial and ventrolateral medulla
of neonate rats.
AB - The H+-sensitivity of neonate rat cultured neurons derived from the dorsomedial
medulla (DMM) containing the nucleus tractus solitarii and the ventrolateral
medulla (VLM) was determined by H+-sensitive fluorescent probe BCECF-AM and
immunohistochemical methods. Against an extracellular pH as low as 7.2-7.3, H+
sensitivity was verified in 2.6% of the DMM neurons (46/ 1800) and 2.1% of the
VLM neurons (38/1800). This H+-sensitive neurons of the DMM were immunoreactive
to glutamate (52.4%) and glutamic acid decarboxylase (GAD) (28.6%), while those
of the VLM were immunoreactive to glutamate (66.7%) and GAD (33.3%). There was no
immunoreactivity to tyrosine hydroxylase, phenylethanolamine-N-methyltransferase
or choline acetyltransferase in the H+-sensitive neurons are present in the DMM
and VLM besides the ventral medullary surface, the site of the central
chemoreceptors.
PMID- 9756352
TI - Reduced O-glycosylated clathrin assembly protein AP180: implication for synaptic
vesicle recycling dysfunction in Alzheimer's disease.
AB - Synapse loss is one of the neuropathologies in Alzheimer's disease (AD) that may
play a crucial role in the mechanism of its distinct cognitive impairment and
dementia. In a previous study [18], a significant reduction of O-glycosylated
clathrin assembly protein AP180 was observed in neocortex of AD. The reduction
correlated with the density of neurofibrillary tangles. In this study we further
determine that the O-GlcNAc/AP180 ratio is not changed, but the level of AP180
protein decreases in AD. Furthermore, whereas the level of neurofilament (NF-M)
remains relatively unchanged, another clathrin assembly protein, AP-2, is also
reduced in AD along with a small loss of synaptophysin. Our findings suggest that
synaptic vesicle recycling dysfunction may be involved in the pathology of
synapse loss in AD.
PMID- 9756353
TI - A parametric analysis of the 'rate effect' in the sensorimotor cortex: a
functional magnetic resonance imaging analysis in human subjects.
AB - We studied the effects of different movement speeds of unimanual right hand
movements on functional magnetic resonance signal changes in the sensorimotor
cortex using echo planar imaging (EPI). Six healthy right-handed subjects were
scanned at rest and while executing a finger tapping task with their right index
finger. Movement frequency was visually paced at rates ranging from 0.5 to 5 Hz,
separated by 0.5 Hz steps. The blood oxygen level dependent (BOLD) response
within the left sensorimotor cortex was linearly and positively related to
movement frequency. However, this relation holds (r2 = 0.91) only for movement
frequencies faster than 1 Hz (1.5-5 Hz). For the slower frequencies there was an
initial sharp increase of the BOLD response from 0.5 to 1 Hz followed by an
activity drop for 1.5 Hz. These results are compatible with the idea that two
different motor control modes are operative during slow or fast movements. During
slow movements a computational demanding on-line feedback control mode is
operative resulting in strong BOLD signals indicating extensive neural activity.
During faster movements on the other hand a program-like motor control mode is
operative resulting in less demanding neural computations. The amount of neural
computation for the latter control mode increases with increasing movement speed.
PMID- 9756354
TI - The action of local anaesthetics on the compound action potential is altered by
the nature of the permeant ion in frog nerve.
AB - Compound action potentials were recorded from the isolated frog sciatic nerve
using either sodium or lithium as the permeant ion, and an assessment of the
action of local anaesthetics was made. The compound action potentials evoked from
the nerve were not different in terms of their mean amplitude or time to peak
whether recorded with sodium or lithium as the permeant ion. The local
anaesthetics tested, procaine, lignocaine and benzocaine, were more potent, as
measured by their IC50 values, by 2.3, 2.1 and 1.8 times, respectively, when
lithium rather than sodium was used as the permeant ion. The sensitivity of the
nerves to tetrodotoxin was not significantly different whether sodium or lithium
was used as the permeant ion. The slope of the concentration inhibition curves
was not significantly altered in the presence of sodium or lithium for any of the
compounds tested. These results are consistent with the idea that the binding
site for local anaesthetics is intimately associated with the pore region of the
channel and that the nature of the permeant ion can alter the interaction of the
drugs with the sodium channel. However, since this is not a common feature of all
compounds which block sodium channels by interacting at the pore, it may help
refine the existing structural models of sodium channels.
PMID- 9756355
TI - Effect of sciatic nerve crush on local and target tissue production of
neurotrophin-3 transcripts in rats.
AB - The effect of sciatic nerve crush in adult rats on neurotrophin-3 (NT-3) mRNA
expression at the site of crush and in ipsilateral foot skin was studied using
competitive reverse transcription-polymerase chain reaction (cRT-PCR). Mid
sciatic nerve crush resulted in a significant reduction in the expression of NT-3
mRNA in nerve segments distal to the injury site at 3 and 7 days (approximate 60%
decrease; P < 0.01). The reduced NT-3 rnRNA expression started to increase at
days 14 post-crush and returned towards control levels at 21 days following the
crush. The nerve segment proximal to the crush site showed a similar changed
pattern of NT-3 mRNA expression. The effects of denervation on NT-3 mRNA
expression in foot skin were also studied. Reduced expression of NT-3 was
observed by 7 days post-crush, with a 25% decrease observed by 14 days (P <
0.002). Levels of NT-3 mRNA had returned to normal by 21 days post-crush. The
results show that changes in axon-Schwann cell contact do not account for the
nerve crush induced loss, or subsequent recovery, of NT-3 mRNA expression in
nerve.
PMID- 9756356
TI - Effects of alpha-pompilidotoxin on synchronized firing in networks of rat
cortical neurons.
AB - We studied the effect of a novel neurotoxin, alpha-pompilidotoxin (alpha-PMTX) on
the spontaneously synchronized network firing of cultured rat cortical neurons.
Alpha-PMTX acted immediately and irreversibly to disrupt synchronous activity,
leaving only residual sparse, uncorrelated firing and was effective at
concentrations of 10 nM. In the presence of bicuculline to block inhibitory
synaptic transmission, the shutdown in synchronized activity occurred with a
significant delay, required a higher concentration of alpha-PMTX (> 100 nM), and
was preceded by a transiently increased level of firing. It appears that both
inhibitory and excitatory neuronal activity or synaptic transmission are
amplified by alpha-PMTX, but that intense activity eventually leads to
inactivation or transmitter depletion.
PMID- 9756357
TI - The anti-craving drug acamprosate inhibits the conditioned place aversion induced
by naloxone-precipitated morphine withdrawal in rats.
AB - The anti-craving drug acamprosate (Ca N-acetylhomotaurinate) is therapeutically
used to prevent a relapse in weaned alcoholics. In the present place conditioning
study, the effect of this compound on the motivational impact of morphine
withdrawal was examined. Withdrawal was precipitated in rats by administration of
the opioid antagonist naloxone (0.1 mg/kg, s.c.) 5-6 days after the subcutaneous
implantation of a 75 mg morphine pellet. Aversion against the naloxone-paired
cues was observed after conditioning in the drug-free state. The acquisition of
conditioned place aversion was completely inhibited by the pretreatment with
acamprosate (200 mg/kg, i.p.) 12 h and 30 min prior to conditioning. These
results clarify that acamprosate inhibits the motivational component of morphine
withdrawal and suggest that ethanol and opiates share similar properties in the
neuronal mechanisms of conditioned withdrawal and craving.
PMID- 9756358
TI - Evidence for the activity of five adenosine-3',5'-monophosphate-degrading
phosphodiesterase isozymes in the adult rat neocortex.
AB - In the present study, the expression of the activity of adenosine-3',5'
monophosphate-degrading phosphodiesterases (cAMP-PDEs) was analyzed in rat
neocortex homogenates. Following separation by anion-exchange chromatography, the
isozymes were characterized by their sensitivity to modulators and by their
kinetic properties. We identified the activity of five distinct cAMP-PDE
isozymes: two calcium/calmodulin-dependent forms (PDE 1), one PDE 2 isozyme
stimulated by guanosine-3',5'-monophosphate (cGMP), one cGMP-inhibited form (PDE
3) and a cAMP-specific, rolipram-sensitive form (PDE 4). Our study provides, for
the first time, evidence for the existence of PDE 3 enzyme activity in rat
neocortex and predicts the expression of at least two isoforms (splice variants)
of PDE 1A in this brain area. The existence of different cAMP-degrading
phosphodiesterases modulated by different intracellular second messengers
(calcium and cGMP) suggests that the activity of neocortical neurons and glia
cells is regulated, inter alia, by a 'crosstalk' between calcium-, cGMP- and cAMP
dependent second messenger pathways.
PMID- 9756359
TI - The role of N-methyl-D-aspartate receptor in the guinea pig inner ear after
unilateral labyrinthectomy.
AB - To investigate the role of the N-methyl-D-aspartate (NMDA) receptor in the
vestibular periphery, vestibular compensation in the guinea pig was studied
following chemical unilateral labyrinthectomy by osmotic pump administration of
streptomycin sulfate (SM) with or without D-2-amino-5-phosphonovalerate (D-APV),
one of the NMDA receptor antagonists. All animals administrated SM (SM group) or
SM and D-APV (SM + D-APV group) showed spontaneous nystagmus and head tilt. The
maximum degree of yaw head tilt in the SM + D-APV group was statistically smaller
than that in the SM group. Moreover the time constant for head tilt in the SM + D
APV group was statistically shorter than that in the SM group. These results
indicate that the NMDA receptor in the vestibular periphery influences vestibular
compensation after unilateral labyrinthectomy.
PMID- 9756360
TI - Voltage- and use-dependent inhibition by amphetamine of field potentials and Na+
current in rat nucleus accumbens neurons.
AB - The psychostimulant amphetamine (AMPH) is known to act as an indirect dopamine
agonist by promoting dopamine release. Here we demonstrate direct AMPH inhibition
of field potentials and Na+ currents in rat nucleus accumbens (NAc) neurons. The
experiments were done with field potential recordings from NAc slices and whole
cell recordings from isolated NAc neurons. In NAc slices, AMPH inhibited the
field potentials. The inhibition increased when the NAc neurons were depolarized
with higher extracellular K+ or when the field potentials were evoked at a higher
rate. In isolated NAc neurons, AMPH inhibited the Na+ currents. The inhibition
increased when Na+ currents were activated from more depolarized holding
potentials or were activated more frequently. The voltage- and use-dependent
inhibition of field potentials and Na+ currents by AMPH suggests a similar
mechanism of AMPH action with local anesthetics and antiarrhythmic drugs.
PMID- 9756361
TI - Identification of shyc, a novel gene expressed in the murine developing and adult
nervous system.
AB - The embryonal carcinoma cell line P19 responds to treatment with retinoid acid by
differentiation into neuronal cell types [2]. Using radioactively labeled cDNA
derived from differentiating P19 cells we screened an adult mouse brain cDNA
library and isolated a gene named shyc for selective hybridizing clone. The
encoded protein did not reveal homology to any known protein. We used in situ
hybridization on mouse embryonic and adult brain sections to study shyc
expression. The developing and embryonic nervous system showed the most prominent
hybridization signals. In the adult brain the olfactory pathway was marked by
shyc expression.
PMID- 9756362
TI - Serotonin2A receptor-like immunoreactivity in rat cerebellar Purkinje cells.
AB - In the present study we examined the distribution pattern of serotonin2A (5-HT2A)
receptors in the rat cerebellum. A strong immunoreaction against 5-HT2A receptor
protein was observed in Purkinje cells. A dense cluster of immunopositive
dendritic profiles of Purkinje cells was located beneath the pia matter of
cerebellar cortex. Somal profiles in the cerebellar nuclei had weak to moderate
immunoreactions.
PMID- 9756363
TI - Programs promoting timely sequential antimicrobial therapy: an American
perspective.
AB - Interventional programs promoting the timely conversion of intravenous to oral
antimicrobial therapy have been reported from several hospitals in the U.S.A. and
elsewhere. Factors influencing the initiation and conduct of these programs
include technological advances, changes in health care delivery or reimbursement,
publication of supportive clinical data and growth of clinical pharmacy services.
Successful programs employ comprehensive, multidisciplinary strategies to contain
antimicrobial-related expenditures using interventions based on structured
criteria. Future emphasis on cost-effective drug therapy, advances in computer
based information technology and development of care maps can have favourable
influences on the growth of these programs in the U.S.A.
PMID- 9756364
TI - Strategies to rationalize sepsis management--a review of 4 years' experience in
Dundee.
AB - Hospitals worldwide are facing an unprecedented crisis of rising cost of
antibacterials due to the increasing rapid emergence and dissemination of
antibiotic-resistant organisms, improper use of antibiotics and the use of broad
spectrum parenteral agents. The last 25 years has seen the introduction of many
measures to improve the quality of sepsis management, and specifically
antimicrobial use. The present paper reviews the development, implementation and
evaluation of some of the key strategies employed within the Dundee Teaching
Hospitals NHS Trust (DTHT) to enhance recognition and assessment of sepsis and to
rationalize the early and often empiric antibiotic treatment of patients in
hospital with infection. Particular emphasis is given to optimizing the use of
expensive parenteral agents in conjunction with promotion of oral switch therapy
where appropriate.
PMID- 9756365
TI - Sequential antimicrobial therapy: comparison of the views of microbiologists and
pharmacists.
AB - Sequential antimicrobial therapy (SAT) is arousing keen interest in
microbiologists and pharmacists. In an attempt to obtain information from these
groups regarding the use of SAT in hospitals, an anonymized postal survey was
carried out. A SAT questionnaire was circulated to consultant medical
microbiologists, clinical microbiologists, and heads of pharmacy departments
within the British Isles. Four hundred and forty-seven microbiologists and
pharmacists returned completed questionnaires, giving a response rate of 29%.
Just over half of medical microbiologists (MM) and pharmacists (PH) indicated
that SAT was used in their institution in respiratory medicine, geriatrics,
surgery and, significantly, to a lesser degree in paediatrics. The most common
infections treated were pneumonia, bronchitis and wound infection. However, there
were significant differences between MM and PH, with MM favouring greater use of
SAT in peritonitis (P=0.03), septicaemia (P<0.01), bone infection (P<0.01),
pyelonephritis (UTI) (P<0.01), and PH favouring use in bronchitis (P<0.01). The
ability to take oral fluids or a recognition of no potential absorption problems
were key criteria in the decision process leading to the institution of SAT by MM
and PH. Significantly more MM favoured employing criteria such as temperature <38
degrees C (P<0.01), no requirement for high tissue concentrations (P=0.02) and
evidence of response to i.v. antimicrobial therapy (P<0.01) than PH. The most
frequently "switched" antimicrobials were metronidazole, ciprofloxacin and co
amoxiclav. There were more than five times as many MM reporting the use of
clindamycin than PH (P<0.01), whereas nearly twice as many PH cited use of
cefuroxime (P<0.01). Of those hospitals not employing SAT, most MM and PH
concurred that the commonest reason to institute SAT was financial, followed by
convenience to patients and staff. However, more PH than MM indicated that
protocols (P<0.01) and a reduction in i.v. complications (P<0.01) were important
to them. In promoting SAT, MM and PH felt they had the major role. Significantly,
each profession felt that the other had a lesser role to play; MM as judged by
the PH (P<0.01) and PH as judged by MM (P<0.01). When promoting SAT, both MM and
PH felt that "education for clinicians" followed by regular audit was the best
way to ensure implementation. However, significant differences arose with PH
regarding nurse education (P<0.01), SAT posters (P=0.02), regular review of
patients (P=0.04) and patient's notes SAT stickers (P<0.01) as more important to
them than MM. Significantly, less MM than PH (P<0.01) insisted that either the
i.v. and PO antimicrobials were identical or were from the same group or class
when "switching". This survey highlights interesting comparisons between the
approaches of MM and PH towards SAT and may indicate ways in which both groups
may work together to bring about change.
PMID- 9756366
TI - Assessment criteria in identifying the sick sepsis patient.
AB - Standard definitions of sepsis have been proposed and have been widely adopted.
Recognition of the systemic inflammatory response syndrome (SIRS) and assessment
of its severity can easily be achieved at the bedside using basic observations
and simple laboratory tests. Fulfillment of standardized criteria defining
increasing severity of sepsis or manifestation of two, three and four SIRS
criteria directly correlates with risk of mortality and progression to organ
failure. However, manifestation of only two SIRS criteria identifies patients who
may have relatively mild disease. Furthermore, sepsis definitions take no account
of pre-existing illness, source of infection or causative agent, all of which
have a significant influence on outcome. Despite these limitations, manifestation
of four SIRS criteria or the persistence of markers of severe sepsis identifies
individuals on general wards who are at particularly high risk of death, who
should be closely monitored for deterioration and discussed with an intensive
care physician at an early stage. If the source of sepsis is not clear, empirical
antibiotic therapy for such individuals should be discussed with a medical
microbiologist or infectious diseases physician.
PMID- 9756367
TI - Sequential antimicrobial therapy: pharmacokinetic and pharmacodynamic
considerations in sequential therapy.
AB - The pharmacodynamic factors important in sequential therapy are largely unknown.
This is because most pharmacodynamic investigations concentrate on how bacterial
populations respond to first antimicrobial exposures. However, it is likely that
for B lactams T>MIC and for quinolones the antimicrobial AUC/MIC ratio will be
important. Factors which reduce antimicrobial absorption will impact on these
parameters and require further study.
PMID- 9756368
TI - Sequential antibiotic therapy: the right patient, the right time and the right
outcome.
AB - The aim of sequential therapy should be to provide better quality of care at
lower cost. In comparison with i.v. therapy, oral administration is safer, more
acceptable to the patient, facilitates early discharge from hospital and reduces
the cost of consumables. However, if given to the wrong patient, oral
antimicrobial therapy could both increase the cost and reduce the quality of
care, either because of ineffective treatment, or unnecessary prolongation of
treatment. Hospitals must develop policies for sequential therapy which define
standards against which clinical care can be audited. The standards will need to
be revised as new data become available from local audit and from research.
Further research on sequential therapy is undoubtedly required, with particular
emphasis on the reliability of absorption of oral drugs by hospitalized patients.
PMID- 9756369
TI - Cost issues in sequential therapy.
AB - Pharmacoeconomics is starting to be employed in strategic therapeutic decision
making. Costs associated with antimicrobials included: (i) acquisition costs;
(ii) preparation, administration and consumables costs; (iii) monitoring costs;
(iv) costs of unwanted drug effects; (v) costs of resistance and therapeutic
failures and (vi) costs of duration of stay. Most hospitals have a Drug and
Therapeutics Committee but acquisition costs are still the most important
economic criterion for acceptance for use, even though medicines only consume
between 3 and 5% of total revenue costs, of which antibiotics account for around
15%. In any sequential programme acquisition costs and consumables are
immediately realizable. Staff time and monitoring tests are less realizable but
require changes in the way budgets are handled. Microbial resistance and risk
management are difficult to quantify but are increasingly becoming important in
strategic decision-making. The educational needs of health care decision makers
in economic need addressing and mechanisms need to be put in place to enable the
putative savings reported in the pharmacoeconomic literature to be realized.
PMID- 9756370
TI - Implementation of sequential therapy programs--a microbiologist's view.
AB - Sequential antimicrobial therapy is not new, but confusion about the timing and
nature of the switch often negates perceived advantages. A common problem is the
choice of oral antibiotic to follow empirical administration of an intravenous
second or third generation cephalosporin. Where guidelines do not exist,
particularly when data are lacking as the the best option, the Delphi technique
of obtaining a consensus agreement by review of a series of case histories is
recommended. Majority verdicts are used to determine what is acceptable practice,
and as such the approach is also suitable for audit. Savings through reduced drug
acquisition costs and shorter lengths of stay have been highlighted. However,
other less obvious potential benefits of sequential antimicrobial therapy include
reduced incidence of intravascular catheter infection because of shorter line
dwell times and less endoluminal contamination. Sequential antimicrobial therapy
may also be used as part of a policy to reduce the selective pressure,
particularly due to cephalosporin use, for endemic hospital pathogens such as
Clostridium difficile and extended spectrum producing gram-negative baccilli.
PMID- 9756371
TI - Implementation of sequential therapy programmes--a pharmacist's view.
AB - Sequential antibiotic therapy has a number of advantages in terms of patient
benefit and value for money in drug use. Introduction and maintenance of a
process to ensure sequential therapy is multidisciplinary, involving clinicians,
pharmacists, microbiologists and possibly nurses. The contribution of pharmacists
is multi-faceted and involves senior and junior pharmacists working in a number
of areas. Pharmacy managers will be involved at policy setting level through the
Drug and Therapeutics committee and similar bodies. Purchasing and formulary
pharmacists will be involved in negotiating purchasing agreements while clinical
pharmacists provide data on the costs and outcomes of treatment. The drug
information pharmacist is a valuable resource in searching and interpreting the
available literature. Whatever system is used, clinical pharmacists have an
important role in identifying patients and monitoring prescribing. In many
schemes described in the literature, pharmacists have had an important role in
auditing the effectiveness of sequential therapy. There may be scope for
developing the clinical pharmacist's role further by devolving, under protocol,
increased decision making and medicines management responsibilities.
PMID- 9756372
TI - Tumour necrosis factor-alpha as a target of melanocortins in haemorrhagic shock,
in the anaesthetized rat.
AB - The cytokine tumour necrosis factor-alpha (TNF-alpha) is involved (mostly through
the activation of inducible nitric oxide synthase) in the pathogenesis of
circulatory shock. On the other hand, melanocortin peptides are potent and
effective in reversing haemorrhagic shock, both in animals (rat, dog) and in
humans. This prompted us to study the influence of the melanocortin peptide ACTH
(1-24) on the blood levels of TNF-alpha in haemorrhage-shocked rats and on the in
vitro production of TNF-alpha by lipopolysaccharide (LPS)-activated macrophages.
Plasma levels of TNF-alpha were undetectable before starting bleeding and greatly
increased 20 min after bleeding termination in saline-treated rats. In rats
treated with ACTH-(1-24) the almost complete restoration of cardiovascular
function was associated with markedly reduced levels of TNF-alpha 20 min after
bleeding termination. On the other hand, ACTH-(1-24) did not influence TNF-alpha
plasma levels in sham-operated, unbled rats. In vitro, ACTH-(1-24) (25-100 nM)
dose-dependently reduced the LPS-stimulated production of TNF-alpha by peritoneal
macrophages harvested from untreated, unbled rats. These results indicate that
inhibition of TNF-alpha overproduction may be an important component of the
mechanism of action of melanocortins in reversing haemorrhagic shock.
PMID- 9756373
TI - Potent antihyperglycaemic property of a new imidazoline derivative S-22068 (PMS
847) in a rat model of NIDDM.
AB - Recent data suggest that some imidazoline derivatives can lower plasma glucose in
experimental animal models of diabetes. We studied the activity of an imidazoline
S-22068, in rat model of non-insulin-dependent diabetes mellitus (NIDDM) produced
with a low dose of streptozotocin (35 mg kg(-1), i.v.) in the adult. The
respective increase over basal value in glucose (deltaG) and insulin (deltaI),
and the rate of glucose disappearance (K), were measured during a 30 min
intravenous glucose tolerance test. After an intraperitoneal injection of S-22068
(24 mg kg(-1)), deltaG (mM min(-1)) was decreased (91.67+/-5.83 vs 120.5+/-3.65;
P<0.001), whereas K was increased (1.74+/-0.09 vs 1.18+/-0.05; P<0.001). Although
insulinaemia was increased at time-point 0 of the test, deltaI was unchanged.
During oral glucose tolerance tests (OGTT), S-22068 (24 mg kg(-1), p.o.) improved
glucose tolerance, and its efficiency was potentiated after chronic treatment (15
days). Basal glycaemia was unaffected by the treatment. Under the same
conditions, a higher dose of S-22068 (40 mg kg(-1)) further improved glucose
tolerance without causing hypoglycaemia. Binding experiments revealed that S
22068 displays no affinity for either adrenoceptors or the two imidazoline
receptors I1 or I2. These results demonstrate that S-22068 improves glucose
tolerance without causing hypoglycaemia. Thus S-22068 represents a new potential
option in the treatment of NIDDM.
PMID- 9756374
TI - Purinoceptor activation of chloride transport in cystic fibrosis and CFTR
transfected pancreatic cell lines.
AB - The regulation of chloride efflux from cystic fibrosis pancreatic adenocarcinoma
cells (CFPAC-1) and wild-type CFTR-transfected CFPAC-1 cells (TPAC) was compared.
Forskolin (10 microM) stimulated chloride efflux from the corrected TPAC cells
but not from CFPAC-1 cells. Chloride efflux from both cell types was activated by
thapsigargin (0.5 microM). The nucleotides ATP and UTP and the non-hydrolyzable
ATP analogue, adenosine 5'-O-(3-thio) triphosphate (ATPgammaS), stimulated
chloride efflux from both cell types. None of the other P2 purinoceptor agonists
investigated elicited a response. The order of potency was ATP > or = UTP > or =
ATPgammaS. Adenosine (10-100 microM) activated choride efflux from the TPAC but
not the CFPAC cell line with no increase in intracellular cyclic AMP. Small but
statistically significant inhibitions of the adenosine-(50 microM)-stimulated
increase in chloride efflux were elicited by the A1 receptor antagonist 8
cyclopentyl-1,3-dipropylxanthine (CPX, 100 nM) and the A2 receptor antagonist 3,7
dimethyl-1-propylargylxanthine (DMPX, 10 microM). The A2A receptor antagonist 8
(3-chlorostyryl)caffeine (CSC, 100 nM) had no significant effect. These results
provide evidence for the regulation of chloride efflux by P2Y2 purinoceptors in
genetically-corrected and CF pancreatic cell lines. Studies with adenosine
receptor antagonists indicate some possible involvement of A1 and A2 (but not
A2A) receptors in the adenosine stimulation of chloride efflux, but the
relatively small effects of the inhibitors coupled with lack of increase in
cyclic AMP and a response only in the CFTR-transfected cells also suggests a
possible direct effect of adenosine on CFTR.
PMID- 9756375
TI - Presynaptic and postsynaptic actions of halothane at glutamatergic synapses in
the mouse hippocampus.
AB - Whole-cell patch-clamp recordings in adult mouse hippocampal slices were used to
test the mechanism by which the volatile anesthetic halothane inhibits glutamate
receptor-mediated synaptic transmission. Non-N-methyl-D-aspartate (nonNMDA) and
NMDA receptor-mediated currents in CA1 pyramidal cells were pharmacologically
isolated by bath application of D,L-2-amino-5-phosphonovaleric acid (APV; 100
microM) or 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX; 5 microM), respectively.
Halothane blocked both nonNMDA and NMDA receptor-mediated excitatory postsynaptic
currents (EPSCs) to a similar extent (IC50 values of 0.66 and 0.57 mM,
respectively). Partial blockade of the EPSCs by lowering the extracellular
concentration of calcium ([Ca2+]o), but not by application of CNQX (1 microM),
was accompanied by an increase in paired-pulse facilitation (PPF). Halothane
induced blockade of the EPSCs also was associated with an increase in PPF. The
effects of halothane on alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid
(AMPA) and NMDA receptor-mediated currents induced by agonist iontophoresis, were
compared. AMPA-induced currents were blocked with an IC50 of 1.7 mM. NMDA-induced
currents were significantly less sensitive to halothane (IC50 of 5.9 mM). The
effect of halothane on iontophoretic AMPA dose-response curves was tested.
Halothane suppressed the maximal response to AMPA without affecting its EC50,
suggesting a noncompetitive mechanism of inhibition. All effects of halothane
were reversible upon termination of the exposure to the drug. These data suggest
that halothane blocks central glutamatergic synaptic transmission by
presynaptically inhibiting glutamate release and postsynaptically blocking the
AMPA subtype of glutamate receptors.
PMID- 9756376
TI - Characterization of an atypical muscarinic cholinoceptor mediating contraction of
the guinea-pig isolated uterus.
AB - In many smooth muscle tissues a minor M3-muscarinic acetylcholine (mACh) receptor
population mediates contraction, despite the presence of a larger M2-mACh
receptor population. However, this is not the case for guinea-pig uterus where
radioligand binding and functional studies exclude a dominant role for M3-mACh
receptors. Using tissue from animals pre-treated with diethylstilboestrol,
estimates of antagonist affinity were made before and after selective alkylation
procedures, together with estimates of agonist affinity to characterise the mACh
receptor population mediating carbachol-induced contraction of guinea-pig
isolated uterus. Antagonist affinity estimates made at 'protected' receptors were
not significantly different from those made in untreated tissues. However all
estimations were significantly different from those reported in guinea-pig ileum
and atria. The rank order of affinities were atropine>zamifenacin=tripitramine>
methoctramine. Carbachol-induced contractions were insensitive to the M4
selective muscarinic toxin MTx-3, or PD102807 (0.1 microM) ruling out a role for
M4-mACh receptors. The agonist affinity value for L-660,863, a putative 'M2
selective' agonist of 5.44+/-0.30 (n=6) was significantly different from that
reported in guinea-pig atria. In contrast, the pKA value for carbachol (4.22+/
0.17 n = 8) agrees with that reported for guinea-pig ileum. Carbachol-induced
contractions were insensitive to pertussis toxin although carbachol-induced
inhibition of forskolin-stimulated cyclic AMP production was attenuated, ruling
out the involvement of Gi-proteins in contraction. Radioligand binding studies
revealed a KD for N-[3H]-methylscopolamine of 0.12+/-0.05 nM and a Bmax of 147+/
18 fmol mg protein(-1). Antagonist affinity estimates made using competition
binding studies supported previous data suggesting the presence of a homogenous
population of M2-mACh receptors. These data suggest a small population of mACh
receptors with an atypical operational profile which can not be distinguished
using radioligand binding studies may mediate carbachol-induced contraction of
guinea-pig isolated uterus.
PMID- 9756377
TI - Mechanisms of galanin-induced contraction in the rat myometrium.
AB - A neuropeptide, galanin, regulates the reproductive process and directly induces
myometrial contraction. The aim of this study was to determine the mechanism of
galanin-induced myometrial contraction. For this purpose, we simultaneously
measured intracellular Ca2+ concentration ([Ca2+]i) and tension using fura-PE3
fluorometry and the rat longitudinal myometrium. The effect of galanin on the
Ca2+ sensitivity of the contractile apparatus was examined in beta-escin
permeabilized strips. The expression of galanin and the galanin receptors mRNAs
in the rat myometrium were determined by reverse transcription polymerase chain
reaction (RT-PCR). Galanin (10-300 nM) induced phasic contraction with or without
oscillation in the pregnant rat myometrium in a concentration-dependent manner.
The maximal response was obtained at 100 nM. There was no significant difference
either in the maximal responses or EC50 values for galanin-induced myometrial
contractions among myometriums from non-pregnant and pregnant (day 4, day 11, day
20, day 22) rats. In the day 20 and 22 pregnant myometriums, assigning the levels
of [Ca2+]i and tension at 40 mM K+-depolarization to be 100%, galanin increased
the [Ca2+]i and tension to 126.9+/-2.9% and 116.3+/-2.7%, respectively. Diltiazem
(10 microM) inhibited the galanin-induced elevation of [Ca2+]i and tension to
71.9+/-2.4% and 16.2+/-0.7%, respectively. Ni2+, by itself, decreased the basal
[Ca2+]i to -50.2+/-3.9% without affecting resting tension. After Ni2+ treatment,
galanin-induced increases in [Ca2+]i and tension were -19.6+/-3.4% and 0.9+/
0.1%, respectively. In myometrium treated with diltiazem, no oscillation in
[Ca2+]i and tension was observed. In Ca2+-free solution with 0.1 mM EGTA, galanin
increased [Ca2+]i from -40.2+/-2.7% to -18.0+/-2.6% and induced transient
contraction (3.6+/-0.8%). In beta-escin permeabilized myometrium, galanin
enhanced the contraction induced by 0.3 microM Ca2+ in the presence of GTP. In
the presence of GDPbetaS (1 mM) instead of GTP, galanin failed to increase the
Ca2+ sensitivity of the contractile apparatus. RT-PCR revealed that galanin mRNA
was hardly expressed in the non-pregnant rat myometrium and increased to reach a
maximal level at mid pregnancy (day 11), but decreased to the same level as in
the non-pregnant myometrium at term (day 22). Type 2 galanin receptor (GALR2)
mRNA was found to be expressed in the rat myometrium whereas type 1 galanin
receptor (GALR1) mRNA expression was not detected. In conclusion, galanin induces
contraction of the rat myometrium by increasing [Ca2+]i as well as by increasing
Ca2+ sensitivity of the contractile apparatus. Galanin-induced increases in
[Ca2+]i are caused by both intracellular Ca2+ release and Ca2+ influx from
extracellular space. The responsiveness of the rat myometrium to galanin does not
change during pregnancy. The galanin mRNA is expressed in the rat myometrium and
it is upregulated during mid-pregnancy. Rat myometrium expresses GALR2 but not
GALR1 mRNA. By changing mRNA expression in the myometrium during pregnancy,
galanin may act as a paracrine or autocrine mediator in the regulation of
myometrial contractility.
PMID- 9756378
TI - Analgesic and sedative concentrations of lignocaine shunt tonic and burst firing
in thalamocortical neurones.
AB - The effects of lignocaine [lidocaine] HCl (0.6 microM(-1) mM) on the membrane
electrical properties and action potential firing of neurones of the ventral
posterolateral (VPL) nucleus of the thalamus were investigated using whole cell
recording techniques in rat brain slices in vitro. Bath application of lignocaine
reversibly decreased the input resistance (Ri) of VPL neurones. This effect was
observed at low, clinically sedative and analgesic concentrations (i.e., maximal
amplitude at 10 microM) whereas higher concentrations (300 microM(-1) mM) had no
effect on Ri. Lignocaine (10-100 microM) depolarized VPL neurones up to 14 mV in
a reversible manner. Consistent with a decreased Ri, low concentrations of
lignocaine shunted the current required for spike generation in the tonic
pattern. Lignocaine increased the threshold amplitude of current required for
firing and decreased the tonic firing frequency, without concomitant elevation of
the voltage threshold for firing or reduction in the maximal rate of rise
(dV/dt(max)) of spikes. Low concentrations of lignocaine shunted low threshold
spike (LTS) burst firing evoked either from hyperpolarized potentials or as
rebound bursts on depolarization from prepulse-conditioned potentials. Higher
concentrations of lignocaine (300 microM - 1 mM), not associated with a decrease
in Ri, elevated the voltage threshold for firing and reduced the dV/dt(max) of
spikes in a concentration-dependent fashion. In conclusion, low concentrations of
lignocaine shunted tonic and burst firing in VPL neurones by decreasing Ri, a
mechanism not previously described for local anaesthetics in the CNS. We suggest
that a decreased resistance in thalamocortical neurones contributes to the
sedative, analgesic, and anaesthetic properties of systemic lignocaine in vivo.
PMID- 9756379
TI - Potent inhibition of both the acute and delayed emetic responses to cisplatin in
piglets treated with GR205171, a novel highly selective tachykinin NK1 receptor
antagonist.
AB - The effects of GR205171, a selective tachykinin NK1 receptor antagonist, were
investigated on both the acute and delayed phases of cisplatin-induced nausea
like behaviour and vomiting in the conscious piglet. Animals receiving cisplatin
(5.5 mg kg(-1), i.v.) were observed for 60 h. Fifteen min prior to cisplatin
infusion (T0(-15 min)), eight piglets acting as controls received an intravenous
injection of saline solution (1 ml kg(-1)), whereas experimental animals received
a single i.v. administration of GR205171 (1 ml kg(-1)) at a dose of 0.01 (n=8),
0.03 (n=8), 0.1 (n = 8), 0.3 (n = 16) or 1.0 (n = 13) mg kg(-1). In eight
additional piglets, GR205171 (1 mg kg(-1)) was administered 15 min before the
onset of the delayed phase (T16(-15 min)). A further five piglets received
GR205171 (1 mg kg(-1)) every 6 h throughout the experiment. The latencies of the
first emetic episode (EE) and nausea-like behavioural episode (NE) increased in
all experimental groups treated at T0(-15 min), and the total number of both EE
and NE during the 60 h was reduced in a dose-dependent manner. In piglets treated
at T0(-15 min) with GR205171 1 mg kg(-1), eight out of 13 (62%) did not vomit
throughout the experiment. Animals treated with GR205171 (1 mg kg(-1)) at T16(-15
min) exhibited an acute response to cisplatin but did not vomit during the
delayed phase. The greatest inhibition of both nausea-like behaviour and vomiting
was observed in piglets receiving multiple injections of GR205171. These results
demonstrate the long-lasting anti-emetic effects of GR205171, and confirm the key
role of substance P within the emetic reflex.
PMID- 9756380
TI - Direct dopamine D2-receptor-mediated modulation of arachidonic acid release in
transfected CHO cells without the concomitant administration of a Ca2+-mobilizing
agent.
AB - In CHO cells transfected with the rat dopamine D2 receptor (long isoform),
administration of dopamine per se elicited a concentration-dependent increase in
arachidonic acid (AA) release. The maximal effect was 197% of controls (EC50=25
nM). The partial D2 receptor agonist, (-)-(3-hydroxyphenyl)-N-n-propylpiperidine
[(-)-3-PPP], also induced AA release, but with somewhat lower efficacy (maximal
effect: 165%; EC50=91 nM). The AA-releasing effect of dopamine was counteracted
by pertussis toxin, by the inhibitor of intracellular Ca2+ release, 8-(N N
diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), by excluding calcium from
the medium, by the phospholipase A2 (PLA2) inhibitor, quinacrine, and by long
term pretreatment with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate
(TPA). In addition, it was antagonized by the D2 antagonists, raclopride and (-)
sulpiride--but not by (+)-sulpiride--and absent in sham-transfected CHO cells
devoid of D2 receptors. The results obtained contrast to the previous notion that
dopamine and other D2 receptor agonists require the concomitant administration of
calcium-mobilizing agents such as ATP, ionophore A-23187 (calcimycin), thrombin,
and TRH, to influence AA release from various cell lines.
PMID- 9756381
TI - Structural determinants for binding to CGRP receptors expressed by human SK-N-MC
and Col 29 cells: studies with chimeric and other peptides.
AB - Structure-activity relationships for the binding of human alpha-calcitonin gene
related peptide 8-37 (halphaCGRP8-37) have been investigated at the CGRP
receptors expressed by human SK-N-MC (neuroblastoma) and Col 29 (colonic
epithelia) cells by radioligand binding assays and functional assays (halphaCGRP
stimulation of adenylate cyclase). On SK-N-MC cells the potency order was
halphaCGRP8-37 > halphaCGRP19-37 = AC187 > rat amylin8-37 > halpha[Tyr0]-CGRP28
37 (apparent pKBs of 7.49+/-0.25, 5.89+/-0.20, 6.18+/-0.19, 5.85+/-0.19 and
5.25+/-0.07). The SK-N-MC receptor appeared CGRP1-like. On Col 29 cells, only
halphaCGRP8-37 of the above compounds was able to antagonize the actions of
halphaCGRP (apparent pKB=6.48+/-0.28). Its receptor appeared CGRP2-like.
halpha[Ala11,18]-CGRP8-37, where the amphipathic nature of the N-terminal alpha
helix has been reduced, bound to SK-N-MC cells a 100 fold less strongly than
halphaCGRP8-37. On SK-N-MC cells, halphaCGRP8-18,28-37 (M433) and mastoparan
halphaCGRP28-37 (M432) had apparent pKBs of 6.64+/-0.16 and 6.42+/-0.26,
suggesting that residues 19-27 play a minor role in binding. The physico-chemical
properties of residues 8-18 may be more important than any specific side-chain
interactions. M433 was almost as potent as halphaCGRP8-37 on Col 29 cells
(apparent pKB=6.17+/-0.20). Other antagonists were inactive.
PMID- 9756382
TI - Pharmacological characterization of a rat 5-hydroxytryptamine type3 receptor
subunit (r5-HT3A(b)) expressed in Xenopus laevis oocytes.
AB - The present study has utilized the two electrode voltage-clamp technique to
examine the pharmacological profile of a splice variant of the rat orthologue of
the 5-hydroxytryptamine type 3A subunit (5-HT3A(b)) heterologously expressed in
Xenopus laevis oocytes. At negative holding potentials, bath applied 5-HT (300 nM
- 10 microM) evoked a transient, concentration-dependent (EC50 = 1.1+/-0.1
microM), inward current. The response reversed in sign at a holding potential of
2.1+/-1.6 mV. The response to 5-HT was mimicked by the 5-HT3 receptor selective
agonists 2-methyl-5-HT (EC50= 4.1+/-0.2 microM), 1-phenylbiguanide (EC50=3.0+/
0.1 microM), 3-chlorophenylbiguanide (EC50 = 140+/-10 nM), 3,5
dichlorophenylbiguanide (EC50 = 14.5+/-0.4 nM) and 2,5-dichlorophenylbiguanide
(EC50 = 10.2+/-0.6 nM). With the exception of 2-methyl-5-HT, all of the agonists
tested elicited maximal current responses comparable to those produced by a
saturating concentration (10 microM) of 5-HT. Responses evoked by 5-HT at EC50
were blocked by the 5-HT3 receptor selective antagonist ondansetron (IC50=231+/
22 pM) and by the less selective agents (+)-tubocurarine (IC50=31.9+/-0.01 nM)
and cocaine (IC50 = 2.1+/-0.2 microM). The data are discussed in the context of
results previously obtained with the human and mouse orthologues of the 5-HT3A
subunit. Overall, the study reinforces the conclusion that species differences
detected for native 5-HT3 receptors extend to, and appear largely explained by,
differences in the properties of homo-oligomeric receptors formed from 5-HT3A
subunit orthologues.
PMID- 9756383
TI - U937 cells deprived of endogenous annexin 1 demonstrate an increased PLA2
activity.
AB - Annexin 1 (An 1), a phospholipid and calcium binding protein, is strongly
expressed in differentiated U 937 cells. In attempting to correlate the
expression of An 1 with phospholipase A2 (PLA2) activity, U 937 cells were stably
transfected both with a Sense and Antisense cDNA for An 1. PLA2 activity was
measured by Flow cytometry analysis utilizing the bis-Bodipy-C11-PC fluorescent
probe. U 937 cells stably transfected with the sense or antisense vectors were
differentiated for 24 h with phorbol 12-myristate 13-acetate (PMA, 6 ng ml(-1)).
Both in undifferentiated and differentiated cells, the Antisense clone (36.4 AS)
showed consistently higher PLA2 activity than the control Sense clone (15 S).
Since the fluorescent probe measures the total PLA2 activity, we used two
different stimuli, PMA: (100 ng ml(-1)) or lipopolysaccharide (LPS, 10 ng ml(
1)), and two different inhibitors, to discriminate the PLA2 involved (namely
arachidonyl trifluoromethyl ketone or AACOCF3, which is specific for the
cytosolic PLA2, and SB 203347 specific for the secretory PLA2). In the Antisense
clone the inhibitory effect of AACOCF was stronger [68%, P<0.025] than in the
Sense, which may reflect the lower endogenous level of An 1 present in the cells.
On the contrary, the inhibitory effect of SB 203347 [60% of inhibition] was
identical in both clones. Since cPLA2 activity is correlated with its
phosphorylation, Western and shift blot analysis were performed. They did not
show any significative difference between the phosphorylated and non
phosphorylated form of the enzyme in both the differentiated or not, Sense and
Antisense clones. Furthermore the tyrosine phosphorylation analysis of An 1
showed that less than 10% of An 1 was phosphorylated irrespective of PMA presence
or absence. From the pattern of inhibition observed, we propose that the
endogenous unphosphorylated form of An 1 may act intracellularly to block the
activity of a cytosolic PLA2.
PMID- 9756384
TI - Metabolic response to various beta-adrenoceptor agonists in beta3-adrenoceptor
knockout mice: evidence for a new beta-adrenergic receptor in brown adipose
tissue.
AB - The beta3-adrenoceptor plays an important role in the adrenergic response of
brown and white adipose tissues (BAT and WAT). In this study, in vitro metabolic
responses to beta-adrenoceptor stimulation were compared in adipose tissues of
beta3-adrenoceptor knockout and wild type mice. The measured parameters were BAT
fragment oxygen uptake (MO2) and isolated white adipocyte lipolysis. In BAT of
wild type mice (-)-norepinephrine maximally stimulated MO2 4.1+/-0.8 fold.
Similar maximal stimulations were obtained with beta1-, beta2- or beta3
adrenoceptor selective agonists (dobutamine 5.1+/-0.3, terbutaline 5.3+/-0.3 and
CL 316,243 4.8+/-0.9 fold, respectively); in BAT of beta3-adrenoceptor knockout
mice, the beta1- and beta2-responses were fully conserved. In BAT of wild type
mice, the beta1/beta2-antagonist and beta3-partial agonist CGP 12177 elicited a
maximal MO2 response (4.7+/-0.4 fold). In beta3-adrenoceptor knockout BAT, this
response was fully conserved despite an absence of response to CL 316,243. This
unexpected result suggests that an atypical beta-adrenoceptor, distinct from the
beta1-, beta2- and beta3-subtypes and referred to as a putative beta4
adrenoceptor is present in BAT and that it can mediate in vitro a maximal MO2
stimulation. In isolated white adipocytes of wild type mice, (-)-epinephrine
maximally stimulated lipolysis 12.1+/-2.6 fold. Similar maximal stimulations were
obtained with beta1-, beta2- or beta3-adrenoceptor selective agonists (TO509 12+/
2, procaterol 11+/-3, CL 316,243 11+/-3 fold, respectively) or with CGP 12177
(7.1+/-1.5 fold). In isolated white adipocytes of beta3-adrenoceptor knockout
mice, the lipolytic responses to (-)epinephrine, to the beta1-, beta2-, beta3
adrenoceptor selective agonists and to CGP 12177 were almost or totally
depressed, whereas those to ACTH, forskolin and dibutyryl cyclic AMP were
conserved.
PMID- 9756385
TI - Effect of increased cardiac output on liver blood flow, oxygen exchange and
metabolic rate during longterm endotoxin-induced shock in pigs.
AB - We investigated hepatic blood flow, O2 exchange and metabolism in porcine
endotoxic shock (Control, n = 8; Endotoxin, n = 10) with administration of
hydroxyethylstarch to maintain arterial pressure (MAP)>60 mmHg. Before and 12, 18
and 24 h after starting continuous i.v. endotoxin we measured portal venous and
hepatic arterial blood flow, intracapillary haemoglobin O2 saturation (Hb-O2%) of
the liver surface and arterial, portal and hepatic venous lactate, pyruvate,
glycerol and alanine concentrations. Glucose production rate was derived from the
plasma isotope enrichment during infusion of [6,6-2H2]-glucose. Despite a
sustained 50% increase in cardiac output endotoxin caused a progressive,
significant fall in MAP. Liver blood flow significantly increased, but endotoxin
affected neither hepatic O2 delivery and uptake nor mean intracapillary Hb-O2%
and Hb-O2% frequency distributions. Endotoxin nearly doubled endogenous glucose
production rate while hepatic lactate, alanine and glycerol uptake rates
progressively decreased significantly. The lactate uptake rate even became
negative (P<0.05 vs Control). Endotoxin caused portal and hepatic venous pH to
fall significantly concomitant with significantly increased arterial, portal and
hepatic venous lactate/pyruvate ratios. During endotoxic shock increased cardiac
output achieved by colloid infusion maintained elevated liver blood flow and
thereby macro- and microcirculatory O2 supply. Glucose production rate nearly
doubled with complete dissociation of hepatic uptake of glucogenic precursors and
glucose release. Despite well-preserved capillary oxygenation increased
lactate/pyruvate ratios reflecting impaired cytosolic redox state suggested
deranged liver energy balance, possibly due to the O2 requirements of
gluconeogenesis.
PMID- 9756386
TI - A discriminant block among K+ channel types by phenytoin in neuroblastoma cells.
AB - The action of the anticonvulsant drug phenytoin on K+ channels was investigated
in neuroblastoma cells (N2A) by using the single-channel patch-clamp technique.
N2A cells expressed three types of delayed rectifier K+ channels, which were
found to have a conductance of 10-20 pS in a 'physiological' K+ gradient. When
added to the external solution at concentrations ranging between 1 and 200
microM, phenytoin decreased single channel activity, whereas the unitary current
amplitude was unaffected in all three types of channels. The open probability of
the biggest channel decreased, according to an exponential distribution of open
and closed times, from 40% in control conditions to 10% in the presence of 50
microM phenytoin (Vm=40 mv). The reduction in the open-channel probability was
concentration-dependent with a IC50 = 27.2+/-0.9 microM. A transient type of K
channel was identified that was affected by cumulative inactivation and had a
conductance of a mean value equal to 26 pS. Finally, a voltage-and Ca2+-dependent
K+ channel with a unitary conductance of 95 pS was recorded. Both the channel's
amplitude and kinetics were unaffected by phenytoin. These results confirm the
phenytoin effect on K+ currents and suggest that the drug may be considered a
selective blocker of delayed rectifier K+ channels.
PMID- 9756387
TI - Evidence that tachykinins are the main NANC excitatory neurotransmitters in the
guinea-pig common bile duct.
AB - Application of electrical field stimulation (EFS; trains of 10 Hz, 0.25 ms pulse
width, supramaximal voltage for 60 s) to the guinea-pig isolated common bile duct
pretreated with atropine (1 microM), produced a slowly-developing contraction
('on' response) followed by a quick phasic 'off' contraction ('off peak'
response) and a tonic response ('off late' response), averaging 16+/-2, 73+/-3
and 20+/-4% of the maximal contraction to KCl (80 mM), n=20 each, respectively.
Tetrodotoxin (1 microM; 15 min before) abolished the overall response to EFS (n
8). Neither in vitro capsaicin pretreatment (10 microM for 15 min), nor
guanethidine (3 microM, 60 min before) affected the excitatory response to EFS (n
5 each), showing that neither primary sensory neurons, nor sympathetic nerves
were involved. Nomega-nitro-L-arginine (L-NOARG, 100 microM, 60 min before) or
naloxone (10 microM, 30 min before) significantly enhanced the 'on' response
(294+/-56 and 205+/-25% increase, respectively; n=6-8, P<0.01) to EFS. The
combined administration of L-NOARG and naloxone produced additive enhancing
effects (655+/-90% increase of the 'on' component, n = 6, P<0.05). The tachykinin
NK2 receptor-selective antagonist MEN 11420 (1 microM) almost abolished both the
'on' and 'off late' responses (P<0.01: n=5 each) to EFS, and reduced the 'off
peak' contraction by 55+/-8% (n=5, P<0.01). The subsequent administration of the
tachykinin NK1 receptor-selective antagonist GR 82334 (1 microM) and of the
tachykinin NK3 receptor-selective antagonist SR 142801 (30 nM), in the presence
of MEN 11420 (1 microM), did not produce any further inhibition of the response
to EFS (P>0.05; n=5 each). At 3 microM, GR 82334 significantly reduced (by 68+/
9%, P<0.05, n=6) the 'on' response to EFS. The contractile 'off peak' response to
EFS observed in the presence of both MEN 11420 and GR 82334 (3 microM each) was
abolished (P<0.01; n=6) by the administration of the P2 purinoceptor antagonist
pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS, 30 microM). PPADS
(30 microM) selectively blocked (75+/-9 and 50+/-7% inhibition, n = 4 each) the
contractile responses produced by 100 and 300 microM ATP. Tachykinin-containing
nerve fibres were detected by using immunohistochemical techniques in all parts
of the bile duct, being distributed to the muscle layer and lamina propria of
mucosa. In the terminal part of the duct (ampulla) some labelled ganglion cells
were observed. In conclusion, this study shows that in the guinea-pig terminal
biliary tract tachykinins, released from intrinsic neuronal elements, are the
main NANC excitatory neurotransmitters, which act by stimulating tachykinin NK2
(and possibly NK1) receptors. ATP is also involved as excitatory
neurotransmitter. Nitric oxide and opioids act as inhibitory mediators/modulators
in this preparation.
PMID- 9756388
TI - MS-551 and KCB-328, two class III drugs aggravated adrenaline-induced
arrhythmias.
AB - We investigated the proarrhythmic effects of MS-551 and KCB-328, class III
antiarrhythmic drugs using adrenaline-induced arrhythmia models in halothane
anaesthetized, closed-chest dogs. In the control period, adrenaline, starting
from a low dose of 0.25 to up to 1.0 microg/kg/50 s i.v., was injected to
determine the arrhythmia inducing dose and the non-inducing dose. After MS-551 or
KCB-328 administration, the adrenaline injection was repeated and the interval
between the injection and the occurrence of arrhythmia (latent interval), the
changes in arrhythmic ratio (as calculated by dividing the number of ventricular
premature contraction by the number of the total heart rate) and the severity of
arrhythmia were observed. MS-551 infusion, 1 mg/kg/30 min, decreased the heart
rate (HR) by 16% (P<0.01) and prolonged the QTc interval by 20% (P<0.01). During
the 30 min of MS-551 infusion, arrhythmias occurred in three out of seven dogs
(torsades de pointes (TdP) type VT in one dog). After these arrhythmias
disappeared, MS-551 decreased the latent interval of the adrenaline arrhythmias
produced by the inducing dose (30+/-2 s compared with 43+/-3 s of the control
interval, P < 0.05), increased the arrhythmic ratio (P<0.05) and induced
arrhythmias by non-inducing adrenaline doses (P<0.05). Effect of a new class III
drug KCB-328 infusion, 0.3 mg/kg/30 min, was compared witih MS-551 using the same
model. KCB-328 decreased the HR by 21% (P<0.01) and prolonged the QTc interval by
25% (P<0.01). During the 30 min of infusion, arrhythmias occurred in five out of
seven dogs (TdP in two dogs). KCB-328 also decreased the latent interval of the
adrenaline arrhythmias produced by the inducing doses (31+/-3 s compared with
49+/-7 s of the control period, P<0.05), but did not significantly alter the
arrhythmic ratio. Adrenaline induced TdP only after MS-551 or KCB-328 was
administered, i.e. after MS-551, 1 mg/kg/30 min, 3/7 versus 0/7 in the control;
KCB, 0.3 mg/kg/30 min, 3/7 versus 0/7 in the control. To examine the direct
arrhythmogenic effect of MS-551 and whether an adrenergic mechanism plays some
role on this arrhythmogenesis, a bolus injection of MS-551, 3 mg/kg, was injected
either without pre-treatment or after pre-treatment with propranolol 0.3 mg/kg.
MS-551 induced arrhythmias in five out of seven dogs (TdP in one dog). Also in
the propranolol pre-treated dogs, MS-551 induced arrhythmias in five out of seven
dogs (TdP in 1 dog). In conclusion, these observations indicate that MS-551 and
KCB-328 induced arrhythmias and intensified proarrhythmic effects of adrenaline,
MS-551 being stronger than KCB-328 at the same QTc prolonging doses. The direct
arrhythmogenic effect of MS-551 was not influenced by beta-blocker treatment.
PMID- 9756389
TI - Modulation of IL-1-induced cartilage injury by NO synthase inhibitors: a
comparative study with rat chondrocytes and cartilage entities.
AB - Nitric oxide (NO) is produced in diseased joints and may be a key mediator of IL
1 effects on cartilage. Therefore, we compared the potency of new [aminoguanidine
(AG), S-methylisothiourea (SMT), S-aminoethylisothiourea (AETU)] and classical
[Nomega-monomethyl-L-arginine (L-NMMA), Nomega-nitro-L-arginine methyl ester (L
NAME)] NO synthase (NOS) inhibitors on the inhibitory effect of recombinant human
interleukin-1beta (rhIL-1beta) on rat cartilage anabolism. Three different
culture systems were used: (1) isolated chondrocytes encapsulated in alginate
beads; (2) patellae and (3) femoral head caps. Chondrocyte beads and cartilage
entities were incubated in vitro for 48 h in the presence of rhIL-1beta with a
daily change of incubation medium to obtain optimal responses on proteoglycan
synthesis and NO production. Proteoglycan synthesis was assessed by incorporation
of radiolabelled sodium sulphate [Na2(35)SO4] and NO production by cumulated
nitrite release during the period of study. Chondrocytes and patellae, as well as
femoral head caps, responded concentration-dependently to IL-1beta challenge (0
to 250 U ml(-1) and 0 to 15 U ml(-1) respectively) by a large increase in nitrite
level and a marked suppression of proteoglycan synthesis. Above these
concentrations of IL-1beta (2500 U ml(-1) and 30 U ml(-1) respectively),
proteoglycan synthesis plateaued whereas nitrite release still increased thus
suggesting different concentration-response curves. When studying the effect of
NOS inhibitors (1 to 1000 microM) on NO production by cartilage cells stimulated
with IL-1beta (25 U ml(-1) or 5 U ml(-1)), we observed that: (i) their ability to
reduce nitrite level decreased from chondrocytes to cartilage samples, except for
L-NMMA and AETU; (ii) they could be roughly classified in the following rank
order of potency: AETU > L-NMMA > or = SMT > or = AG > or = L-NAME and (iii) AETU
was cytotoxic when used in the millimolar range. When studying the effect of NOS
inhibitors on proteoglycan synthesis by cartilage cells treated with IL-1beta, we
observed that: (i) they had more marked effects on proteoglycan synthesis in
chondrocytes than in cartilage samples; (ii) they could be roughly classified in
the following rank order of potency: L-NAME > or = L-NMMA > > AG > SMT > > AETU
and (iii) potentiation of the IL-1 effect by AETU was consistent with
cytotoxicity in the millimolar range. D-isomers of L-arginine analog inhibitors
(1000 microM) were unable to correct nitrite levels or proteoglycan synthesis in
IL-1beta treated cells. L-arginine (5000 microM) tended to reverse the correcting
effect of L-NMMA (1000 microM) on proteoglycan synthesis, thus suggesting a NO
related chondroprotective effect. However, data with L-NAME and SMT argued
against a general inverse relationship between nitrite level and proteoglycan
synthesis. Dexamethasone (0.1 to 100 microM) (i) failed to inhibit NO production
in femoral head caps and chondrocytes beads whilst reducing it in patellae (50%)
and (ii) did not affect or worsened the inhibitory effect of IL-1beta on
proteoglycan synthesis. Such results suggested a corticosteroid-resistance of rat
chondrocyte iNOS. Data from patellae supported a possible contribution of
subchondral bone in NO production. In conclusion, our results suggest that (i) NO
may account only partially for the suppressive effects of IL-1beta on
proteoglycan synthesis, particularly in cartilage samples; (ii) the
chondroprotective potency of NOS inhibitors can not be extrapolated from their
effects on NO production by joint-derived cells and (iii) L-arginine analog
inhibitors are more promising than S-substituted isothioureas for putative
therapeutical uses.
PMID- 9756390
TI - Involvement of ET(A) and ET(B) receptors in the activation of phospholipase D by
endothelins in cultured rat cortical astrocytes.
AB - This study was performed to characterize the receptor subtypes involved in the
endothelin stimulation of phospholipase D (PLD) in rat cortical astrocytes in
primary culture. PLD activity was determined by measuring the formation of
[32P]phosphatidylbutanol in [32P]orthophosphate prelabelled cells stimulated in
the presence of 25 mM butanol. The agonists endothelin-1 (ET-1), endothelin-3 (ET
3), sarafotoxin 6c (S6c) and IRL 1620 elicited PLD activation in a concentration
dependent manner. The potencies of ET-1, ET-3 and S6c were similar. The maximal
effects evoked by the ET(B)-preferring agonists, ET-3, S6c and IRL 1620, were
significantly lower than the maximal response to the non-selective agonist ET-1.
The response to 1 nM ET-1 was inhibited by increasing concentrations of the ET(A)
receptor antagonist BQ-123 in a biphasic manner. A high potency component of the
inhibition curve (24.2+/-3.5% of the ET-1 response) was defined at low (up to 1
microM) concentrations of BQ-123, yielding an estimated Ki value for BQ-123 of
21.3+/-2.5 nM. In addition, the presence of 1 microM BQ-123 significantly reduced
the maximal response to ET-1 but did not change the pD2 value. Increasing
concentrations of the ET(B) selective antagonist BQ-788 inhibited the S6c
response with a Ki of 17.8+/-0.8 nM. BQ-788 also inhibited the effect of ET-1,
although, in this case, two components were defined, accounting for approximately
50% of the response, and showing Ki values of 20.9+/-5.1 nM and 439+/-110 nM,
respectively. The ET-1 concentration-response curve was shifted to the right by 1
microM BQ-788, also revealing two components. Only one of them, corresponding to
69.8+/-4.4% of the response, was sensitive to BQ-788 which showed a Ki value of
28.8+/-8.9 nM. Rapid desensitization was achieved by preincubation with ET-1 or
S6c. In cells pretreated with S6c neither ET-3 nor S6c activated PLD, but ET-1
still induced approximately 40% of the response shown by non-desensitised cells.
This remaining response was insensitive to BQ-788, but fully inhibited by BQ-123.
In conclusion, endothelins activate PLD in rat cortical astrocytes acting through
both ET(A) and ET(B) receptors, and this response desensitizes rapidly in an
apparently homologous fashion. The percentage contribution of ET(A) and ET(B)
receptors to the ET-1 response was found to be approximately 20% and 80%,
respectively, when ET(B) receptors were not blocked, and 30-50% and 50-70%,
respectively, when ET(B) receptors were inhibited or desensitized. These results
may be relevant to the study of a possible role of PLD in the proliferative
effects shown by endothelins on cultured and reactive astrocytes.
PMID- 9756391
TI - Depolarization counteracts glucocorticoid inhibition of adenohypophysical
corticotroph cells.
AB - In AtT20 mouse corticotroph tumour cells large conductance Ca2+-activated K+
channels (BK-channels) have an essential role in the early glucocorticoid
inhibition of adrenocorticotrophin (ACTH) secretion evoked by corticotrophin
releasing factor. The present study examined whether or not BK-channels are also
pivotal to glucocorticoid inhibition of normal rat anterior pituitary cells. A
membrane-permeant, non-metabolizable cyclic AMP analogue, 8-(4
Chlorophenylthio)adenosine-3',5'-cyclic-monophosphate (CPT-cAMP) was used as the
primary secretagogue stimulus, as this mimics the increase of intracellular
cyclic AMP caused by corticotrophin-releasing factor, but is not subject to the
complex Ca2+-dependent regulation of cyclic AMP metabolism that is evident in
corticotroph cells. Experiments in AtT20 cells showed that ACTH secretion
stimulated by 1 mM CPT-cAMP was suppressed to 34+/-1.5% (n = 12) of the control
stimulus by a maximal dose of 100 nM dexamethasone. The ACTH secretion evoked by
the combination of 1 mM CPT-cAMP with either 5 microm (-)BayK8644 (L-type Ca2+
channel activator) or 5 mM TEA (K+-channel blocker) was respectively 69.1+/-7.6%
and 69.3+/-11.8% of control after 2 h preincubation with 100 nM dexamethasone
(P<0.05 vs CPT-cAMP). The ACTH response elicited by 5 microM (-)BayK8644 and 5 mM
TEA given together was completely resistant to inhibition by 100 nM
dexamethasone. Furthermore, TEA and (-)BayK8644 given together synergistically
stimulated ACTH release in combination with 0.1 mM or 1 mM CPT-cAMP, and these
ACTH responses were not inhibited by 100 nM dexamethasone. In primary cultures of
rat anterior pituitary cells, TEA (up to 20 mM), charybdotoxin (30 nM) or apamin
(100 nM) failed to modify the glucocorticoid inhibition of 0.1 mM CPT-cAMP
induced ACTH release. The combination of 5 mM TEA and 5 microM (-)BayK8644
elicited a small but significant increase in ACTH secretion but did not modify
the inhibition of 0.3 mM CPT-cAMP-induced ACTH secretion by 100 nM dexamethasone.
In primary cultures of rat anterior pituitary cells, depolarization of the
membrane potential with 40 mM KCl enhanced the ACTH response to CPT-cAMP and
markedly reduced the maximal inhibitory effect of dexamethasone to 55+/-1.2% as
well as that of corticosterone to 33+/-2.1% vs 100+/-2.5% and 100+/-1.9%
inhibition respectively, when 0.1 mM CPT-cAMP was used alone. Introduction of 5
microM (-)BayK8644 with 40 mM KCl in this system had no additional effect on
glucocorticoid inhibition. No glucocorticoid inhibition of ACTH release to any of
the stimuli applied was observed in cells pretreated with the mRNA synthesis
inhibitor, 5,6-dichloro-furanosyl-benzimidazole riboside (DRB) (0.1 mM) or the
protein synthesis blocker, puromycin (0.1 mM). In summary, early glucocorticoid
inhibition of stimulated ACTH release by cultured rat anterior pituitary cells
was dependent on the synthesis of new mRNA and protein. Depolarization of the
membrane potential potentiated CPT-cAMP-induced ACTH secretion in AtT20 cells as
well as cultured rat corticotrophs and this was associated with a resistance to
the early inhibitory effect of glucocorticoids. Glucocorticoid inhibition in rat
anterior pituitary corticotrophs was unaltered by TEA, charybdotoxin as well as
apamin, and hence it is unlikely to involve predominantly BK-or SK-type Ca2+
activated K+-channels. These results support the thesis that a prime target of
glucocorticoid feedback inhibition in anterior pituitary corticotrophs is the
membrane potential and indicate that glucocorticoid-induced proteins regulate the
activities of several distinct plasma membrane ion channels.
PMID- 9756393
TI - Calcium influx inhibition by steroids and analogs in C2C12 skeletal muscle cells.
AB - Glucocorticoids, namely alpha-methylprednisolone (PDN) and deflazacort, are the
only drugs reported to have a beneficial effect on the degenerative course of
Duchenne muscular dystrophy (DMD). Increased cytosolic calcium concentrations
([Ca2+]c) have been implicated as one of the pathological events responsible for
the degeneration of dystrophic skeletal muscles. In previous studies, we have
demonstrated that PDN treatment of both normal and dystrophic murine skeletal
muscle cells was able to normalize elevated [Ca2+]c and improved myogenesis. Here
we have investigated the mechanism underlying the effects of glucocorticoids on
cellular Ca2+ influx into C2C12 skeletal muscle cells. Long-term incubation of
C2C12 myocytes with PDN was necessary to observe a reduction of 45Ca2+ influx.
PDN was most effective in inhibiting 45Ca2+ uptake when added for 4 days (at the
time of fusion of myoblasts into myotubes) and to a lesser extent, when added
after fusion. It was ineffective when added to C2C12 cells at the myoblast stage.
Short PDN incubation times, at the time of fusion were insufficient to elicit a
response. Several steroids were tested for their ability to inhibit 45Ca2+ influx
in C2C12 myocytes. All four glucocorticoids examined were able to reduce Ca2+
influx, dexamethasone being the most potent (IC50 3.14+/-0.34 x 10(-8) M).
Mineralocorticoids (aldosterone and 11-deoxycorticosterone) were also able to
reduce Ca2+ influx. The vitamin E-derived lazaroid U-83836E and the
glucocorticoid-derived lazaroid U-74389G also elicited a decrease in Ca2+ influx,
but higher concentrations were necessary. Because both glucocorticoids and
lazaroids display antioxidant properties, but U-83836E is devoid of
glucocorticoid activity, the reduction in Ca2+ influx was suspected to be
triggered via an antioxidant mechanism. To test this hypothesis, we assessed the
action of several antioxidants, such as vitamin E, vitamin C, 2-tert.-butyl-4
methoxyphenol (BHA), 2,6-di-tert.-butyl-4-methyl-phenol (BHT) and
nordihydroguaiaretic acid (NDGA), on 45Ca2+ influx. None of these agents had an
effect on 45Ca2+ influx. In addition, several oxidants were tested (either
acutely or chronically) for their ability to elicit 45Ca2+ influx in C2C12
myocytes and were found to be inactive. The involvement of the glucocorticoid
receptor on the modulation of Ca2+ influx was investigated. The glucocorticoid
receptor antagonist mifepristone (code name RU38486, 10(-6) M) caused a shift of
two orders of magnitude of the PDN response. However, neither actinomycin D nor
cycloheximide affected the response to PDN. Results with the phospholipase A2
inhibitor, manoalide, suggest that glucocorticoid-induced protein synthesis (e.g.
enhanced stimulation of lipocortin) does not play a role in the reduction of
calcium influx. Our results suggest that steroids elicit a decrease in calcium
influx in C2C12 skeletal muscle cells. This decrease is not due to an antioxidant
mechanism or to a mechanism which requires gene expression. Since
mineralocorticoids and U-83836E also had similar effects, the mechanism could
belong to the non-genomic effects of corticoids (e.g. membrane stabilization).
The beneficial effect of glucocorticoids in DMD could be attributed to a
reduction of the pathological increase in Ca2+ influx via an effect on the
sarcolemma.
PMID- 9756392
TI - Histamine H1-receptor-mediated increase in the Ca2+ transient without a change in
the Ca2+ current in electrically stimulated guinea-pig atrial myocytes.
AB - The effects of histamine on the intracellular Ca2+ concentration ([Ca2+]i),
action potential and membrane currents were assessed in single atrial myocytes
prepared from guinea-pigs. Histamine caused a concentration-dependent increase in
the [Ca2+]i transient in indol/AM loaded myocytes when stimulated electrically at
0.5 Hz. However, the maximum increase in [Ca2+]i transient produced by histamine
was less than 50% of that elicited by isoprenaline. The histamine-induced
increase in [Ca2+]i transient was significantly inhibited by chlorpheniramine,
but not by cimetidine. Pretreatment with nifedipine nearly completely suppressed
the histamine-induced increase in [Ca2+]i transient. Cyclopiazonic acid did not
affect the histamine response. In the whole-cell current-clamp mode of the patch
clamp method, both histamine and isoprenaline prolonged action potential duration
(APD) in atrial myocytes. In the presence of Co2+ or nifedipine, the isoprenaline
induced APD prolongation was abolished and an APD shortening effect was
manifested, while histamine still increased APD. The APD prolongation elicited by
histamine was reversed by chlorpheniramine. In the voltage-clamp mode, the
histamine-sensitive membrane current was inwardly rectifying and reversed close
to the calculated value of the K+ equilibrium potential. Histamine had no
apparent effect on L-type Ca2+ current, in contrast to the pronounced effect of
isoprenaline. These results indicate that in guinea-pig atrial myocytes
stimulation of H1-receptors with histamine does not directly activate Ca2+
channels but causes an elevation of [Ca2+]i transient by increasing Ca2+ influx
through the channels during the prolonged repolarization of action potentials
resulting from inhibition of the outward K+ current.
PMID- 9756394
TI - Inhibitors of the activity of poly (ADP-ribose) synthetase reduce the cell death
caused by hydrogen peroxide in human cardiac myoblasts.
AB - Poly (ADP-ribose) synthetase (PARS) is a nuclear enzyme activated by strand
breaks in DNA which are caused by reactive oxygen species (ROS). Inhibitors of
PARS activity reduce the degree of reperfusion injury of the heart in vivo and in
vitro. Here we investigate the role of PARS in the cell death of human cardiac
myoblasts caused by hydrogen peroxide. Exposure of human cardiac myoblasts to
hydrogen peroxide caused a time- and concentration-dependent reduction in
mitochondrial respiration (cell injury), an increase in cell death (LDH release),
as well as an increase in PARS activity. The PARS inhibitors 3-aminobenzamide (3
mM), 1,5-dehydroxyisoquinoline (300 microM) or nicotinamide (3 mM) attenuated the
cell injury and death as well as the increase in PARS activity caused by hydrogen
peroxide (3 mM; 4 h for cell injury/death, 60 min for PARS activity) in human
cardiac myoblasts. In contrast, the inactive analogues 3-aminobenzoic acid (3 mM)
or nicotinic acid (3 mM) were without effect. The iron chelator deferoxamine (1
10 mM) caused a concentration-dependent reduction in the cell injury and death
caused by hydrogen peroxide in these human cardiac myoblasts. Thus, the cell
injury/death caused by hydrogen peroxide in human cardiac myoblasts is secondary
to the formation of hydroxyl radicals and due to an increase in PARS activity. We
therefore propose that activation of PARS contributes to the cell injury/cell
death associated with oxidant stress in the heart.
PMID- 9756395
TI - L-687,414, a low efficacy NMDA receptor glycine site partial agonist in vitro,
does not prevent hippocampal LTP in vivo at plasma levels known to be
neuroprotective.
AB - N-methyl-D-aspartic acid (NMDA) receptors are known to play a key role in the
induction phase of long-term potentiation (LTP) at certain hippocampal synapses
and to represent some component of spatial learning in animals. The ability of
NMDA receptor antagonists (or gene knockout) to impair LTP has led to the
suggestion that the therapeutic use of such antagonists may impair cognitive
function in humans. The present study compares the effects on LTP of NMDA
receptor ion channel block by MK-801 and glycine-site antagonism by 3R(+)cis-4
methyl-pyrrollid-2-one (L-687,414). In vitro experiments using rat cortical
slices revealed L-687,414 to be approximately 3.6 fold more potent than its
parent analogue, R(+)HA-966 at antagonizing NMDA-evoked population
depolarizations (apparent Kbs: 15 microM and 55 microM, respectively). Whole-cell
voltage-clamp experiments using rat cultured cortical neurones revealed L-687,414
to shift to the right the concentration-response relationship for NMDA-evoked
inward current responses (pKb=6.2+/-0.12). L-687,414 affinity for the glycine
site on the NMDA receptor complex was also determined from concentration
inhibition curves, pKi=6.1+/-0.09. In the latter experiments, L-687,414 and
R(+)HA-966 were unable to completely abolish inward current responses suggesting
each compound to be a low efficacy partial agonist (estimated intrinsic activity
= approximately 10 and 20% of glycine, respectively). L-687,414 and MK-801 were
compared for their effects on NMDA receptor-dependent LTP in the dentate gyrus of
anaethestized rats following high frequency stimulation of the medial perforant
path (mPP) afferents. Control rats, administered saline (0.4 ml kg(-1) followed
by 0.0298 ml min(-1)), showed a robust augmentation of the population e.p.s.p.
risetime (LTP) recorded in the dentate hilus following tetanic stimulation of the
mPP. LTP was effectively abolished in a separate group of rats treated with an MK
801 dosing regimen (0.12 mg kg(-1) i.v. followed by 1.8 microg kg(-1) h(-1))
known to produce maximal neuroprotection in a rat stroke model but, by contrast,
remained largely intact in a third group of animals given a similarly
neuroprotective L-687,414 treatment (28 mg kg(-1) i.v. followed by 28 mg kg(-1)
h(-1)). These experiments suggest that a low level of intrinsic activity at the
glycine site may be sufficient to support NMDA receptor-dependent LTP but in
circumstances where there is likely to be an excessive NMDA receptor activation
the agonism associated with a low efficacy partial agonist, such as L-687,414, is
dominated by the antagonist properties. Thus, an NMDA receptor partial agonist
profile may offer a therapeutic advantage over neutral antagonists by permitting
an acceptable level of 'normal' synaptic transmission whilst curtailing excessive
receptor activation.
PMID- 9756396
TI - Biphasic effects of cyclosporin A on formyl-methionyl-leucyl-phenylalanine
stimulated responses in HL-60 cells differentiated into neutrophils.
AB - The immunosuppressive drug cyclosporin A (CsA) depresses neutrophil oxidative
burst which may lead to an increased susceptibility to infection in transplant
patients. Using specific CsA analogues we investigated the mechanism of
inhibition of the oxidative burst and evaluated short and long-term effects of
CsA on dimethylsulphoxide-differentiated HL-60 neutrophils. A biphasic pattern
was observed: a 4 h pre-treatment with CsA (1 microM) diminished the fMLP induced
[Ca2+]c rise, reactive oxygen species (ROS) production, and beta-glucuronidase
release by about 40%, whereas a 20 h pre-treatment increased these responses by
about 1.5 fold. [MeVal4]CsA, which binds with high affinity to cyclophilin but
inhibits the interaction of the CsA-cyclophilin complex with calcineurin, blocked
the stimulation observed with CsA after a 20 h incubation but did not alter the
CsA effects after a 4 h pre-treatment. PSC 833 (1 microM), a potent multi drug
resistance transporter (MDR) inhibitor, diminished ROS production to the same
extent as a 4 h CsA incubation but was ineffective after a 20 h pre-treatment. An
involvement of MDR as a basis for CsA or PSC 833 action was ruled out based on
the results of the calcein retention assay. [3H]CsA uptake showed that CsA and
[MeVal4]CsA, but not CsH or PSC 833 were strongly taken up and retained by the
cells. In conclusion, the reduction of the responses after 4 h appear to be due
to a primary reduction of calcium signalling, while the enhanced responses after
20 h may be due to calcineurin inhibition.
PMID- 9756397
TI - Citalopram-induced hypophagia is enhanced by blockade of 5-HT(1A) receptors: role
of 5-HT(2C) receptors.
AB - The selective 5-hydroxytryptamine reuptake inhibitor citalopram (10 and 20 mg kg(
1), i.p.) significantly reduced food intake in male rats (CD-COBS) habituated to
eat their daily food during a 4-h period. The 5-HT1A receptor antagonist
WAY100635 (0.3 mg kg(-1)) administered systemically did not modify feeding but
significantly potentiated the reduction in food intake caused by 10 mg kg(-1)
i.p. citalopram. The dose of 5 mg kg(-1) i.p. citalopram was not active in
animals pretreated with vehicle but significantly reduced feeding in animals
pretreated with WAY100635. WAY100635 (0.1 microg 0.5 microl(-1)) injected into
the dorsal raphe significantly potentiated the hypophagic effect of 10 mg kg(-1)
citalopram. WAY100635 (1.0 microg 0.5 microl(-1)) injected into the median raphe
did not modify feeding or the hypophagic effect of 10 mg kg(-1) citalopram. The 5
HT2B/2C receptor antagonist SB206553 (10 mg kg(-1), p.o.) slightly reduced
feeding by itself but partially antagonized the effect of WAY100635 administered
systemically (0.3 mg kg(-1), s.c.) or into the dorsal raphe (0.1 microg 0.5
microl(-1)) in combination with 10 mg kg(-1) i.p. citalopram. The hypophagic
effect of 10 mg kg(-1) i.p. citalopram alone was not significantly modified by
SB206553. Brain concentrations of citalopram and its metabolite
desmethylcitalopram in rats pretreated with SB206553, WAY100635 and their
combination were comparable to those of vehicle-pretreated rats, 90 min after
citalopram injection. The hypophagic effect of citalopram was potentiated by
blocking 5-HT1A receptors. Only the effect of the WAY100635/citalopram
combination seemed to be partially mediated by central 5-HT2C receptors.
PMID- 9756398
TI - Involvement of CD44 exon v10 in B-cell activation.
AB - The family of CD44 glycoproteins has been suggested to be involved in lymphocyte
homing, maturation and activation. Using in vitro blocking studies with a
monoclonal antibody, we here addressed the question of functional activity of
CD44 variant exon v10 (CD44v10) in B-cell activation. We became interested in
this question by the observation that CD44v10O was transiently expressed on
activated T cells, B cells and monocytes as well as on a subpopulation of bone
marrow cells. A potential ligand, as revealed by staining with a CD44v10 receptor
globulin, was only detected on monocytes. Anti-CD44v10 had no major impact on T
cell activation and no influence on primed B cells, but interfered with the
mounting of a primary B-cell response to T-independent and T-dependent antigens.
Addition of anti-CD44v10 at different stages during the activation process
revealed that CD44v10 was not engaged in B-cell-T-cell interactions. The antibody
exerted some effect on monocyte activation as defined by a slight decrease in IL
1 production, but most efficiently inhibited antigen-specific as well as mitogen
induced B-cell activation when present during the coculture of virgin B cells
with monocytes. These findings, together with the observation that a CD44v10
ligand was only detected on monocytes but not on lymphocytes, point towards a
requirement for CD44v10 in a B-cell-monocyte interaction. Furthermore, since
activation of B cells by engagement both of the B-cell receptor and of mitogen
receptors was inhibited by anti-CD44v10, the data suggest that a costimulatory
function of CD44v10 proceeds independent of the B-cell receptor.
PMID- 9756399
TI - High frequency of altered HLA class I phenotypes in invasive colorectal
carcinomas.
AB - We analyzed the expression of HLA class I antigens in 78 tumor tissue samples
obtained from patients diagnosed as having colorectal carcinomas. A broad panel
of mAbs defining HLA monomorphic, locus-specific and allele-specific determinants
was used. In addition, an antibody defining HLA-C locus-specific determinant
(L31) was also tested. Previous reports on these tumors indicated HLA class I
losses of 30 to 40%. At least 73% of the patients in the present study had a
detectable HLA class I alteration. These altered HLA phenotypes were classified
as total HLA loss (18%) (phenotype I); HLA-A locus-specific loss (9%) (phenotype
IIIa); HLA-B locus-specific loss (8%) (phenotype IIIb); HLA-A and B locus losses
(2%) and HLA allelic losses (36%) (phenotype IV). We found no HLA-C locus losses.
Autologous peripheral blood lymphocyte HLA class I typing was always necessary to
define phenotype IV. We also studied the CD3 zeta chain in tumor tissues to
correlate possible changes in the CD3 signal transduction pathway with HLA
alterations. The CD3 ratio was frequently altered, but this alteration could not
be correlated with tumor HLA phenotypes. The high frequency of HLA class I losses
in colorectal carcinomas suggests that this finding is a widespread phenomenon
and may be required to escape T-cell recognition. It remains to be determined
whether HLA expression is "normal" in the rest of the 27% of our patients.
PMID- 9756400
TI - HLA and alveolar echinococcosis.
AB - Evidence in animal intermediate hosts that susceptibility to larval infection
with Echinococcus multilocularis is restricted to individual host factors
prompted us to investigate the susceptibility markers in humans. Because antigens
of the extracellular parasite E. multilocularis are possibly presented by MHC
molecules in a restricted way, we speculated that MHC polymorphism may influence
resistance of the host towards infection and course of disease. We studied HLA-A,
-B, -DRB1, -DQB1 and -DPB1 polymorphism in 151 patients with alveolar
echinococcosis. Patients with an observation period of more than 2 years were
grouped according to the clinical follow-up into cured (no recurrence following
surgery) patients and patients with regressive or progressive forms of disease
during benzimidazole chemotherapy. By comparing phenotypic frequency between
patients with alveolar echinococcosis and healthy controls, HLA-DRB1*11 was
associated with a reduced risk for disease development (odds ratio=0.55, 95%
confidence interval=0.34-0.88; P=0.01). HLA-DQB1*02 was more frequent in patients
with progressive disease when compared with patients with regressive disease
(54.3% vs 28.3%, P=0.02). The result suggests that HLA-DRB1*11 might confer
protection against alveolar echinococcosis and that HLA-DQB1*02 may indicate a
risk for progressive disease development. The findings may facilitate the search
for immunodominant T-cell epitopes of E. multilocularis.
PMID- 9756401
TI - HLA-DRB and -DQB1 alleles in Polish patients with hepatitis B associated
membranous nephropathy.
AB - We have studied the HLA-DRB and -DQB1 alleles of 42 paediatric patients who have
suffered from membranous nephropathy associated with a hepatitis B infection
(HBVMN). These patients were all from the Gdansk area of Northern Poland and the
disease was diagnosed by light and electron microscopy. The control population
consisted of 55 healthy children, approximately age matched, from schools in
Gdansk. In addition we have also analysed 40 patients chronically infected with
hepatitis B, without any renal involvement, as hepatitis B disease controls. The
HLA alleles were defined using PCR/SSP. As idiopathic membranous nephropathy and
low responsiveness to hepatitis B vaccine have been found to be associated with
DR3 in Caucasoids, our hypothesis was that the HBVMN patients would show an
increase in DR3. Our results indicate that, although there is a small increase in
the frequency of DRBl*0301 in the HBVMN patients (16/42 38%) when compared to the
healthy controls (15/55 31%), this does not approach significance. There is a
significant increase in the frequency of DQB1*0303 in the HBVMN patients vs the
healthy controls, after correction for the number of antigens detected (Pc)(13/42
vs 2/55, RR=11.6, P=0.0007, Pc=0.02). A similar increase in DQB1*0303 is seen in
the HBVMN patients when compared to the hepatitis controls (13/42 vs 4/40) but
this is only significant before correction (RR=4.3, P=0.04).
PMID- 9756402
TI - HLA polymorphisms in Italian bone marrow donors: a regional analysis.
AB - The aim of this study was to analyse the genetic structure of the Italian bone
marrow donor population on the basis of HLA polymorphisms. Maximum likelihood
estimates of gene and haplotype frequencies, goodness of fit to Hardy-Weinberg
predictions and heterozygosity were calculated for 18 Italian administrative
regions. Moreover, the phenotypic peculiarity of the regional populations was
assessed by analysing the number of "typical phenotypes" found in each region.
Multivariate analyses carried out on HLA-A and HLA-B gene frequencies gave a
genetic pattern of the donor pools that reflects the structure of the Italian
population determined in previous population genetic studies. Sardinia shows a
very large genetic difference with respect to the other regions; of these, the
central-southern regions are well-differentiated from the central-northern.
Southern regions present higher genetic heterogeneity and a higher probability of
providing donors with phenotypes not already present in the Italian bone marrow
registry. The large sample size of the bone marrow donor registry allowed us to
estimate gene and haplotype frequencies with greater accuracy than in previous
studies. Our results may be of use in determining strategies for donor
recruitment and selecting unrelated donors for patients requiring bone marrow
grafting, as well as for anthropological, epidemiological and population genetics
studies.
PMID- 9756403
TI - Diversity of HLA-DR2 in North Indians: the changed scenario after the discovery
of DRB1*1506.
AB - DRB1*1506, a new allele of DR2, differs from DRB1*1501 only at codon 50 in the
second exon, where the nucleotide sequence has changed from GTG to GCG resulting
in an amino acid substitution from valine to alanine in DRB1*1506. Since codon 50
was considered non-polymorphic until the discovery of this new allele by sequence
based typing, it became necessary to study what fraction of subjects thought to
have DRB1*1501 actually had DRB1*1506. For this purpose, 116 DNA samples with DR2
coming from normal healthy individuals, leprosy patients and childhood
tuberculosis patients were amplified using PCR and hybridized with 32P-labeled
probes specific for DRB1*1501, DRB1*1502, DRB1*1503, DRB1*1506, DRB1*1601 and
DRB1*1602. The oligonucleotide probe for DRB1*1506 was designed to span codons 47
52 based on the published nucleotide sequence. DRB5, DQA1 and DQB1-specific
amplifications and hybridizations were also carried out to study the diversity of
DR2 haplotypes. It was found that 21% of the samples identified previously as
DRB1*1501 were actually DRB1*1506. DRB1*1506 was found to be associated with
DQB1*0502 and DQB1*0601. Haplotypes of DRB1*1501, DRB1*1502, DRB1*1506 and
DRB1*1602 showed a marked heterogeneity. Besides the rare haplotypes which have
not yet been reported in any other populations, haplotypes characteristic of
different ethnic groups, such as Croatians, South Chinese and Gypsies, were also
found in the North Indians, suggesting the extent of racial admixture and
migrations to and from India.
PMID- 9756404
TI - Polymorphism and distribution of HLA-DR2 alleles and haplotypes in a Greek
population.
AB - HLA-DR2 serological subtyping has indicated that the DR16 serotype appears at a
higher frequency relative to the DR15 serotype in the Greek population, differing
from the distribution observed in most other Caucasian groups. In this study, we
have analyzed by the PCR-SSP technique a DR2-positive group of unrelated Greek
individuals selected from our normal control panel for the different DRB1, DRB5,
DQB1 and DQA1 DR2-associated alleles present. Six of the 50 individuals analyzed
were homozygous for DR2, contributing a total of 56 haplotypes for DR2. The
observed frequencies of the DR2-related DRB1 alleles were as follows: 58.9% for
the DRB1*1601, 7.1% for the DRB1*1602, 25.0% for the DRB1*1501 and 7.1 % for the
DRB1*1502 allele. The rare allele DRB1*1605 was detected in one heterozygous
sample and its presence was definitively established by DNA sequencing. The
alleles *1503, *1504, *1505, *1603 and *1604 were not detected. Three DRB5
alleles were identified: DRB5*0202 (67.8%), DRB5*0101 (25.0%) and DRB5*0102
(7.1%). Ten different DRB1/DQB1/ DQA1 DR2-associated haplotypes were defined. The
most frequently observed haplotype was DRB1*1601-DQB1*0502-DQA1*0102 (relative
frequency=57%) followed by DRB1*1501-DQB1*0602-DQA1*0102 (relative
frequency=14.3%). In conclusion, the refined analysis of the DR2-associated DRB1
alleles in the Greek population revealed the prevalence of the DRB1*1601 allele.
The rare allele DRB1*1605 was demonstrated once. A considerable variety of
different DR2-related DR/DQ haplotypes was detected and the overall haplotypic
frequencies in the Greek population are distributed differently compared to those
reported for most other Caucasian populations.
PMID- 9756405
TI - The PCR-SSP Manager computer program: a tool for maintaining sequence alignments
and automatically updating the specificities of PCR-SSP primers and primer mixes.
AB - An emerging problem of molecular typing methods such as PCR amplification using
sequence-specific primers (PCR-SSP) is that they frequently require updating as
new alleles are constantly being described which potentially affect the
specificity of every PCR-SSP reaction. PCR-SSP uses pairs of primers to detect
cis-linked polymorphisms and thus each new allele described must be compared to
each individual primer pair. Furthermore, sequence homology between the various
loci for class I and class II means that, for example, new HLA-A sequences have
to be compared with HLA-B and HLA-C primer mixes to rule out cross-locus
amplification. We have developed a computer program known as SSP Manager which is
capable of aligning HLA class I and class II sequences obtained from Internet
accessible databases such as GenBank. The program then updates all individual
primer specificities held in its database before updating the specificities of
all primer mixes. Sets of primer mixes can then be combined from the primer mix
directory to create PCR-SSP typing trays which are subsequently analysed by the
program. A report is generated which stipulates whether all known sequences are
amplified and the reason for apparent failure to test for individual alleles,
e.g. a lack of relevant sequence information. SSP Manager has the flexibility to
cope with unusual sequences (deletions and insertions), primers with internal
mismatches and primers with a deliberate mismatch. The program also has many
tools for developing new primer mixes, such as the facility to search for novel
reactions using Boolean operators. The organisation and operational use of the
SSP Manager program is described and its uses are illustrated with an updated
allele list for our previously described Phototyping PCR-SSP class I and class II
typing set. The SSP Manager is available on request from the authors.
PMID- 9756406
TI - HLA-B*27 typing by group-specific hybridization in microtiter plates.
AB - We have developed and evaluated a test for HLA-B*27 based on PCR and DNA
hybridization in microtiter plates. A region within exon 2 of the HLA-B gene is
amplified and labeled by PCR and the amplification product is hybridized to a
group-specific HLA-B*27 and a generic control oligonucleotide probe in two
separate cavities of the plate. Bound sequences are detected using an ELISA-like
protocol. The assay has been evaluated on 254 DNA samples routinely received for
B27 testing in parallel with serological and SSP-PCR typing. Results were
concordant in typing 102 HLA-B27-positive and 152 HLA-B27-negative individuals
except for two samples containing HLA-B*73, which stained B27 positive in the
microwell test. The new procedure is rapid and simple to perform, and the
microwell format is particularly suitable for automation.
PMID- 9756407
TI - HLA-DP-associated susceptibility to the optico-spinal form of multiple sclerosis
in the Japanese.
AB - We studied polymorphism of the HLA-DP gene in 46 patients with optico-spinal form
(Asian type) multiple sclerosis (MS) showing recurrent opticomyelitis and 46
patients with Western type MS with disseminated central nervous system
involvement. We previously reported a significant association between an HLA-DRB1
*1501-DRB5*0101 haplotype and susceptibility to Western type but not Asian type
MS. In the present study, we found that the frequencies of DPA1 *0202 and DPB1
*0501 alleles were significantly increased in patients with Asian type MS, as
compared with findings in 92 healthy control subjects (91.3% vs 65.2%,
P(corr)<0.05 and 89.1% vs 63.0%, P(corr)<0.05 respectively), but not in Western
type MS. Our data provide further evidence that Asian and Western type MS are
distinct regarding the immunogenetic background.
PMID- 9756408
TI - Characterization and distribution of HLA-B*5002 in a Spanish population sample.
AB - HLA-B45, in contrast to B44, does not show molecular polymorphism. We have found
a group of Caucasian Spanish individuals, serologically typed as B45, showing an
unexpected HLA-B12 PCR-SSO subtyping pattern. Complete coding region sequencing
and B45 subtyping by PCR-SSO demonstrated that the B45 serologic specificity is
constituted by two molecular alleles: B*4501 and B*5002. B*5002 is recognized by
polyclonal and monoclonal allosera against B12 and B45, whereas it is not
detected by B21, B49, or B50 reagents, providing a new example of poor
correlation between serology and structure. B*5002 explains an important subset
(18%) of the B45-positive individuals of the Spanish population studied, and
almost half are included in a very infrequent haplotypic association, Cw6-B*5002
DRB1*0406-DQA1*03-DQB1*0402.
PMID- 9756409
TI - Novel polymorphism detected in exon 1 of HLA-B*2713.
PMID- 9756410
TI - Identification of two new DPB1 alleles, DPB1*7701 and *7801, by sequence-based
typing.
PMID- 9756411
TI - Identification of a new DPB1 allele (DPB1*7901) by sequence-based typing.
PMID- 9756412
TI - Nucleotide sequencing reveals a novel DQB1-06 allele (DQB1*06013) with a silent
mutation at codon 137.
PMID- 9756413
TI - Limited importance of CD40/CD40L interaction in the B7-dependent generation of
anti-MOPC-315 cytotoxic T lymphocyte activity by tumor bearer splenic cells
stimulated in vitro in the presence of tumor necrosis factor.
AB - We have previously illustrated the importance of B7-2 expression for the enhanced
generation of cytotoxic T lymphocyte (CTL) activity by stimulation cultures of
tumor bearer splenic cells to which tumor necrosis factor alpha (TNFalpha) has
been added. Here we show that the B7-1 molecule is also important for CTL
generation by such stimulation cultures, although to a much lesser extent than
the B7-2 molecule. In addition, we show the importance of CD40/CD40L interaction
for the expression of the B7-2 molecule, but not the B7-1 molecule, by tumor
bearer splenic cells stimulated in vitro in the presence of TNF. The CD40/CD40L
interaction is also shown to be important for the generation of CTL activity by
tumor bearer splenic cells stimulated in vitro in the presence of exogenous TNF.
However, the CD40/CD40L interaction is less important for the generation of
enhanced CTL activity than for the expression of an elevated level of B7-2.
Specifically, blockade of CD40/CD40L interaction, which reduced the level of B7-2
expressed by tumor bearer splenic cells stimulated in vitro in the presence of
TNF to the level of B7-2 expressed by tumor bearer splenic cells stimulated in
vitro in the absence of exogenous TNF, failed to reduce the level of CTL
generated to the level generated by tumor bearer splenic cells stimulated in the
absence of exogenous TNF. Finally, blockade of CD40/CD40L interaction was
inferior to blockade of B7-2/CD28 interaction in inhibiting the generation of CTL
activity by tumor bearer splenic cells stimulated in the presence of exogenous
TNF. Thus, although CD40/CD40L interaction is important for the generation of
enhanced CTL activity by stimulation cultures of tumor bearer splenic cells to
which TNF has been added, TNF also mediates its potentiating effect for CTL
generation by such stimulation cultures via other mechanisms that are independent
of CD40/CD40L interaction but dependent on B7-2 expression.
PMID- 9756414
TI - Human tumor cells, modified by a novel pressure/crosslinking methodology, promote
autologous lymphocyte proliferation and modulate cytokine secretion.
AB - Hydrostatic pressure (P) combined with membrane protein crosslinking (CL) by
adenosine dialdehyde (AdA) can render tumor cells immunogenic. We have recently
shown that PCL treatment of murine tumor cells augmented the presentation of MHC
restricted tumor-associated antigens and enhanced cell-mediated immunity. In
cancer patients inoculated with autologous PCL-modified tumor cells, a
significant delayed-type hypersensitivity response was elicited. Since the
balance between cell-mediated immunity and humoral immunity is reciprocally
controlled by immunoregulatory cytokines, we have examined the proliferative
response and cytokine secretion pattern in cultures of human peripheral blood
mononuclear cells (PBMC) stimulated by autologous PCL-modified and unmodified
tumor cells. These tumor cells were obtained from freshly resected tumor tissue
of 16 patients with colon (8), lung (4) and renal (4) carcinomas. The results
demonstrated that PCL-modified tumor cells promoted an increase in PBMC
proliferation in 5 out of 8 (63%), 1 out of 4 (25%) and 4 out of 4 (100%) colon,
lung and renal cell carcinomas. Fourteen of the above cultures were also analyzed
for the secretion of interleukin-10 and interferon-gamma. Overall, a substantial
decrease in IL-10 secretion was detected in 9 out of 14 (64%) cultures while a
reciprocal increase in interferon-gamma secretion was noted in 8 out of 14 (57%)
cultures. Our results confirmed that PCL-modified human tumor cells of different
etiologies can modulate the pattern of cytokines released from stimulated
autologous lymphocytes. Such a procedure could prove valuable in the production
of autologous tumor vaccines.
PMID- 9756415
TI - Antibody-dependent difference in biodistribution of monoclonal antibodies in
animal models and humans.
AB - The study was designed to clarify the difference in pharmacokinetics of
monoclonal antibodies (mAb) in animal models and humans, and to elucidate the
applicability of animal models. 99mTc-labeled murine mAb -- against
carcinoembryonic antigen (designated BW431/26), and neural cell adhesion molecule
(NE150) -- and one chimeric mouse/human mAb against nonspecific cross-reacting
antigen (chNCA) were administered i.v. to normal mice and athymic mice (370 kBq,
400 ng) xenografted with human cancer cells expressing antigens, and into
patients with tumor (925 MBq, 1 mg). The biodistribution of two of the three mAb
(not 99mTc-BW431/26) differed clearly in mice and patients. 99mTc-NE150 showed
specific uptake in xenografted tumor and otherwise a normal biodistribution;
however, clinical examination showed increased uptake in the liver with rapid
blood clearance (mean alpha half-life = 31.1 min) compared with 99mTc-BW431/26
(28.4 h). 99mTc-chNCA demonstrated increased blood clearance and renal excretion
in both normal and athymic mice, with accumulation in tumors. Clinical
examination showed rapid blood clearance (mean alpha half-life = 6.4 min) and
increased uptake in the liver. High-performance liquid chromatographic analysis
of 99mTc-chNCA revealed the immune complex in blood, suggesting uptake of the
complex by the reticuloendothelial cells. The biodistribution of radiolabeled mAb
in animal and human models was variable and specific for each of the three mAb.
The results of animal studies with mAb should be evaluated carefully before being
extrapolated to humans, on the basis of the nature of the mAb and interacting
substances.
PMID- 9756416
TI - Evaluation of natural killer cell expansion and activation in vivo with daily
subcutaneous low-dose interleukin-2 plus periodic intermediate-dose pulsing.
AB - Natural killer (NK) cells may be expanded in vivo with a prolonged course of
daily subcutaneous interleukin-2 (IL-2). However, cellular activation requires
higher concentrations of IL-2 than are achieved with low-dose therapy. The
objective of the current trial was to determine the toxicity and immunological
effects of periodic subcutaneous intermediate-dose IL-2 pulses in patients
receiving daily low-dose therapy. A group of 19 patients were treated with daily
subcutaneous low-dose IL-2 at 1.25 x 10(6) International Units (1.25 MIU) m(-2)
day(-1). After 4-6 weeks, patients received escalating 3-day intermediate-dose IL
2 pulses administered as single daily subcutaneous injections, repeated at 2-week
intervals. The maximum tolerated pulse dose was 15 MIU m(-2) day(-1), with
transient hypotension, fatigue, and nausea/vomiting dose-limiting. Subcutaneous
IL-2 resulted in in vivo expansion of CD56+ NK cells (796+/-210%) and CD56bright
natural killer (NK) cells (3247+/-1382%). Expanded NK cells coexpressed CD16, and
showed lymphokine-activated killer activity and antibody-dependent cellular
cytotoxicity in vitro. Intermediate-dose pulsing resulted in serum IL-2
concentrations above 100 pM. Cellular activation was suggested by rapid
margination of NK cells following pulsing, coincident with peak IL-2 levels, with
return to baseline by 24 h. In.addition, interferon gamma production in response
to lipopolysaccharide was augmented. Subcutaneous daily low-dose IL-2 with
intermediate-dose pulsing is a well-tolerated outpatient regimen that results in
in vivo expansion and potential activation of NK cells, with possible application
in the treatment of malignancy and immunodeficiency.
PMID- 9756417
TI - Transcription factor activation in lymphokine activated killer cells and
lymphocytes from patients receiving IL-2 immunotherapy.
AB - Administration of the cytokine interleukin-2 (IL-2) can result in therapeutic
benefits for individuals with renal cell carcinoma and melanoma. Here we report
an analysis of the transcription factor families AP-1, Sp1, NF-kappaB, and signal
transducers and activators of transcription (STAT) in cancer patients'
lymphocytes before and after IL-2 immunotherapy, as assessed by a gel-shift
assay. An in vitro surrogate of IL-2 immunotherapy is the incubation of fresh
peripheral blood mononuclear cells (PBMC) from healthy individuals in IL-2 for
several days, resulting in the production of lymphokine-activated killer (LAK)
activity in these cultures. One purpose of this study was to describe the profile
of transcription factor activation in these different populations, and assess
whether the patterns observed correlated with functional differences in these
cells. Prior to in vivo IL-2 administration, the typical binding pattern of
transcription factors in PBMC from patients resembled that seen in fresh PBMC
from healthy individuals. Over a 3-week course of IL-2 therapy, in most patients
the binding patterns of AP-1 , Sp1, and NF-kappaB proteins changed to resemble
those seen in PBMC activated by IL-2 in vitro. However, the cells obtained from
IL-2-treated patients did not have low-level constitutive expression of STAT
binding factors as did LAK cells. When these patient cells were further
stimulated by IL-2 in vitro, additional differences in STAT induction patterns
were noted. These data provide further information on the molecular events
occurring in immune cells generated through in vivo and in vitro administration
of IL-2, and further document that there is not a precise congruence between PBMC
activated in vivo and in vitro by IL-2.
PMID- 9756418
TI - Polysaccharide K induces Mn superoxide dismutase (Mn-SOD) in tumor tissues and
inhibits malignant progression of QR-32 tumor cells: possible roles of interferon
alpha, tumor necrosis factor alpha and transforming growth factor beta in Mn-SOD
induction by polysaccharide K.
AB - Previously we reported the malignant progression of QR-32, a regressor-type tumor
clone, following co-implantation with foreign bodies (gelatin sponge or plastic
plate) in normal syngeneic C57BL/6 mice. We also reported that the progression of
QR-32 cells by a gelatin sponge was significantly inhibited in the mice
administered polysaccharide K (PSK) and that PSK induced an increase of radical
scavengers, especially manganese superoxide dismutase (Mn-SOD), locally at the
site of tumor tissues. In this study, to reveal the possible mechanism by which
PSK induced Mn-SOD in the tumor tissues, we examined the mRNA expression and
protein levels of inflammatory cytokines in the tissues. We found that mRNAs of
tumor necrosis factor alpha (TNFalpha) and interleukin-1alpha (IL-1alpha) were
considerably expressed in both PSK-treated and phosphate-buffered-saline-treated
tumors, and that the mRNA expression and protein level of interferon gamma
(IFNgamma) increased in the tumor tissues treated with PSK. In vitro treatment of
QR-32 cells with IFNgamma did not significantly increase the production of Mn
SOD; however, the combination of IFNgamma with TNFalpha increased the Mn-SOD
production more effectively than did any of the cytokines used singly.
Furthermore, we observed the down-regulation of the mRNA expression and protein
level of transforming growth factor beta (TGFbeta) in the tumor tissues treated
with PSK, and that in vitro treatment of QR-32 cells with TGFbeta decreased the
production of Mn-SOD. These results suggest that PSK suppresses the progression
of QR-32 cells by increasing Mn-SOD via the modulation of inflammatory cytokines;
that is, by decreasing TGF-beta and increasing IFN-gamma.
PMID- 9756419
TI - Serum anti-p53 autoantibodies in primary resected non-small-cell lung carcinoma.
AB - Mutated p53 proteins accumulate in the nuclei of tumor cells, and anti-p53
autoantibodies are found in the sera of patients with non-small-cell lung
carcinoma (NSCLC). We analyzed the correlation among serum anti-p53
autoantibodies, immunohistochemical staining for p53, and clinical features (age,
gender, smoking history, histological type, differentiation, stage, T factor,
tumor size, and N factor) in resected non-small-cell lung carcinomas. A total of
62 cases of resected NSCLC were studied (43 men and 19 women; 33 adenocarcinomas,
21 squamous cell carcinomas, 8 large-cell carcinomas). Preoperative serum titers
of anti-p53 autoantibodies were detected in 13/62 cases (21.0%). A correlation
between histological type and positive titers of serum p53 autoantibodies was
seen (large-cell carcinoma versus squamous cell carcinoma and adenocarcinoma, P =
0.031, chi2-test). Out of 25 cases, 10 (40%) with positive immunohistochemical
staining for p53 had positive titers, whereas 3 positive titers were found in 37
patients with negative immunohistochemical staining for p53 (P = 0.0025, chi2
test). Serum titers of anti-p53 autoantibodies were present in approximately 20%
of the cases of NSCLC, and overexpression of p53 protein in tumor cells was
detectable in approximately 40%. Serum anti-p53 autoantibodies may be a clinical
parameter for the presence of p53 mutations and p53 overexpression in NSCLC
patients.
PMID- 9756420
TI - Relationship between immune state and tumor growth rate in rats bearing
progressive and non-progressive mammary tumors.
AB - Impaired immune responses occur frequently in cancer patients or in tumor-bearing
animals, but the mechanisms of the tumor-induced immune defects remain poorly
understood. The aim of the present study was to determine the relevance of the
immune system in the control of tumor growth. We have developed a model of
progressive and non-progressive mammary tumor, chemically induced in female
Wistar rats. In this model we evaluated the development of an immune response
after immunization of rats bearing progressive and non-progressive tumors with a
non-related antigen, such as sheep red blood cells. We also studied the
activation state of peritoneal macrophages from animals bearing tumors by
evaluating the production of free radicals. Our findings indicated that the cell
mediated immunity in rats bearing progressive tumors fails to respond to
heterologous antigen in vivo, as demonstrated by a negative delayed-type
hypersensitivity reaction, and is accompanied by minor nitric oxide production by
peritoneal exudate cells as well as a lower capacity for macrophage activation.
The study of non-progressive tumor-bearing rats indicated that the cell-mediated
immune response was intact and an activated state of macrophages was found in
vivo. The results described in this paper should be taken into account when
therapies based on cancer vaccines are chosen for the treatment of cancer.
PMID- 9756421
TI - Noninvasive investigations in vascular disease. St Mary's Fellows. ISVI (Italian
Society for Vascular Investigations).
PMID- 9756422
TI - Diagnosis of renovascular disease by extra- and intrarenal Doppler parameters.
AB - It is still a matter of debate as to which parameters should be used for
noninvasive diagnosis of renovascular disease by renal Doppler sonography (RDS).
The accuracy of RDS in the detection of renal artery stenosis (RAS) was tested in
95 consecutive, moderate to severe hypertensive patients (I-II World Health
Organization [WHO] stages). Reno-aortic ratio (RAR) for peak systolic velocity
(PSV) was also calculated to assist in the diagnosis of significant (>50%) RAS.
Paired receiver-operating characteristic (ROC) analysis was plotted for
evaluating the relationship between sensitivity and specificity for each
parameter. In a subset of 57 kidneys, the influence of blood pressure and age on
intraparenchymal parameters was evaluated. Measurements of maximal peak systolic
velocity (PSV) at the site of stenosis, RAR for PSV, and minimum acceleration
index in the main renal artery showed high accuracy (areas under the ROC curve
0.97, 0.88, and 0.80, respectively). Among intraparenchymal parameters, early
systolic acceleration showed the best area under the ROC curve (0.90), but
provided a low positive predictive value (29%) and was significantly influenced
by blood pressure (multiple r=0.56; p=0.001). Pulsatility and resistive indices
were found to be less powerful as absolute values, and both significantly
influenced by blood pressure and age (multiple r=0.60 and 0.50; p=0.001, p=0.02,
respectively). However, interindividual variance of intrarenal indices should be
minimized by calculation of side difference, although this procedure would become
misleading or impossible in patients with bilateral RAS or a single kidney,
respectively. These results support the use of extraparenchymal parameters for
noninvasive detection of RAS, and emphasize that intrarenal parameters cannot be
considered as absolute values.
PMID- 9756423
TI - Comparison of three blood pressure methods used for determining ankle/brachial
index in patients with intermittent claudication.
AB - The standard noninvasive test to assess the severity of peripheral arterial
occlusive disease (PAOD) is the ankle/brachial systolic blood pressure index
(ABI). While ankle systolic blood pressure is obtained by the Doppler ultrasound
technique, brachial systolic blood pressure can be obtained by the Doppler,
auscultatory, or oscillometric (Dinamap 1846 SX) methods. The purpose was to
determine whether the three methods yielded similar brachial systolic blood
pressure values, and consequently similar ABI values, in PAOD patients with
intermittent claudication. Fifty patients who had a history of intermittent
claudication of 2.3 +/- 2.0 blocks for a duration of 5.7 +/- 5.8 years were
recruited. Following 10 minutes of supine rest, brachial systolic blood pressure
was measured in the right arm by the three techniques in a randomized order, and
ankle systolic blood pressure (87.3 +/- 28.9 mmHg) was measured in the more
symptomatic leg with the Doppler technique. Brachial systolic blood pressure was
not significantly different (p=0.954) among the Doppler (128.5 +/- 18.4 mmHg),
auscultatory (128.4 +/- 17.4 mmHg), and oscillometric (128.2 +/- 17.1 mmHg)
methods. Corresponding ABI values also were similar (p=0.922) among the three
respective methods (0.68 +/- 0.22, 0.68 +/- 0.22, and 0.68 +/- 0.21), indicating
that ABI did not vary according to the technique used to obtain brachial systolic
blood pressure. It is concluded that the accuracy of determining ABI in PAOD
patients with intermittent claudication was minimally affected by the method
chosen to obtain brachial systolic blood pressure.
PMID- 9756424
TI - Venoarteriolar response to experimental venous hypertension in legs with chronic
venous insufficiency and in healthy legs, measured using a double-wavelength
laser Doppler technique.
AB - The venoarteriolar response (VAR) of the skin in legs caused by experimental
venous hypertension was measured using a new, double-wavelength laser Doppler
probe technique (543 nm and 780 nm). This enables the measurement of the laser
Doppler flux in the superficial and deep layers of the skin simultaneously. The
recordings were obtained from the leg with the patient in a recumbent position
with a sphygmomanometer cuff around the thigh. The VAR was recorded at the cuff
pressures of 30 mmHg and 60 mmHg. Ten patients with chronic venous insufficiency
(CVI) and 20 control subjects with healthy legs were investigated. The VAR
increased in relation to the increase of cuff pressure at both wavelengths. There
were no significant differences in the VAR between the cuff pressures within or
between the legs with CVI and healthy legs. The VAR measured at 780 nm was very
significantly greater than the VAR measured at 543 nm in legs with CVI (p<0.005),
as well as in healthy legs (p<0.001). The VAR depends both on the wavelength of
the laser Doppler light used and on the degree of venous hypertension. The VAR is
not impaired in legs with CVI compared with healthy legs.
PMID- 9756425
TI - Gas tensions in cardiac lymph as a reflection of the interstitial space of the
heart.
AB - The purpose of this study was to determine the feasibility of measuring partial
pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), and pH in
cardiac lymph and to evaluate the relationship of these parameters to comparable
measurements in arterial and coronary sinus blood in the normal heart under
various respiratory conditions. In four anesthetized open-chest dogs, the
principal cardiac lymphatic as well as the femoral artery and coronary sinus were
cannulated. Ventilation was varied by changing oxygen concentration, tidal
volume, and respiratory rate. PO2, pCO2, and pH were measured in the cardiac
lymph, arterial blood, and coronary sinus blood after each change in ventilation.
For pH and pCO2, good correlations were observed between the arterial blood and
cardiac lymph, arterial blood and coronary sinus blood, and coronary sinus blood
and cardiac lymph. The correlation between the pO2 measured in the arterial blood
and the pO2 measured in the cardiac lymph was not as strong, and this may have
been related to difficulty achieving a steady state. Gas tensions (pO2, pCO2, and
pH) can be measured in cardiac lymph and may provide a window to the interstitial
compartment of the heart. This is an additional tool for the laboratory study of
ischemia and other forms of heart disease.
PMID- 9756427
TI - Effect of physical activity on the distensibility of the aortic wall in healthy
males.
AB - To study the effect of physical activity level on the distensibility of the human
aortic wall, aortic pulse wave velocity (APWV) was estimated in 139 healthy male
subjects (19-67 years) and was related to the energy expenditure by habitual
physical exercise (physical activity index: PAI), which was evaluated by a 7-day
total activity recall. The subjects consisted of 56 fun runners (runner group)
and 83 general subjects, who were divided into 25 active subjects (active group:
PAI > or = 1,500 kcal/week) and 58 sedentary subjects (sedentary group: PAI <
1,500 kcal/week). The APWV index (APWVI: standardized APWV by the diastolic blood
pressure) was found to be positively correlated with age and was negatively
correlated with PAI. The age-adjusted APWVI of the runner group was significantly
lower than that of the active and sedentary groups. The age-adjusted APWVI was
also significantly lower in the active group than in the sedentary group. These
results suggest that increased physical activity may retard the age-dependent
loss of arterial distensibility in humans, in proportion to the amount and/or
intensity of exercise.
PMID- 9756426
TI - Vasodilatory capacity of forearm resistance vessels is augmented in
hypercholesterolemic patients after treatment with fluvastatin.
AB - Atherosclerotic vessels are characterized by endothelial and structural
abnormalities as indicated by an impaired vasodilation to metabolic requirements.
To determine whether effective treatment of hypercholesterolemia may improve
vasodilatory capacity of resistance vessels, the authors examined the impact of
12 and 24 weeks of lipid-lowering therapy with the hepatic hydroxymethylglutaryl
coenzyme A (HMG-CoA)-reductase inhibitor fluvastatin (40 to 80 mg/day) on the
increment in forearm blood flow during reactive hyperemia in 24
hypercholesterolemic patients (mean age: 56 +/- 11 years; 15 men/9 women).
Changes in forearm blood flow in response to reactive hyperemia were measured by
venous occlusion plethysmography. Serum low-density lipoprotein (LDL)-cholesterol
fell from 213 +/- 32 to 125 +/- 27 mg/dL (P<0.001) after 12 weeks and remained
stable at a level of 125 +/- 18 mg/dL after 24 weeks of treatment. Baseline
forearm blood flow was similar before and after 12 and 24 weeks of therapy. In
contrast, forearm blood flow at peak reactive hyperemia was greater at week 12
(37.0 +/- 22.9 mL/min/100 mL; P<0.05), and at week 24 (47.1 +/- 33.5 mL/min/100
mL; P<0.05) than at week 0 (30.5 +/- 18.1 mL/min/100 mL). Compared with week 0
(defined as 100%), the percent change in forearm blood flow in response to
reactive hyperemia was augmented at week 12 (171 +/- 144%; P<0.05 vs week 0) and
at week 24 (218 +/- 228%; P<0.05 vs week 0). Thus, the lowering of high serum LDL
cholesterol after short-term treatment with fluvastatin increased the blood flow
responses during reactive hyperemia in forearm resistance vessels. These data
indicate a beneficial effect of HMG-CoA reductase inhibition on structural wall
properties of peripheral arteries in human atherosclerosis.
PMID- 9756428
TI - Pulmonary embolism in patients with isolated soleal vein thrombosis.
AB - This study investigated the features of calf deep vein thrombosis (DVT) as a
pulmonary embolic source. Fifty-eight lower limbs in 29 patients who were
suspected of having DVT distal to the popliteal vein were screened by
ultrasonography. Then, ascending venography was performed to confirm the
diagnosis. Pulmonary embolism (PE) was diagnosed in suspected patients by use of
pulmonary perfusion scanning or pulmonary angiography. Venography revealed calf
DVT in 33 limbs in 28 patients. Of 28 patients, six had symptomatic PE.
Thrombosis was found in the muscle veins in 18 limbs, the trunk veins in 11, and
both veins in four. Isolated single vein thrombosis was found in the soleal vein
in 14 limbs (42%), the posterior tibial vein in eight, the peroneal vein in two,
and the gastrocnemius vein in two. The overall percentage of soleal vein thrombi
was 61%. All six patients with symptomatic PE had isolated soleal vein
thromboses. Calf DVT was a pulmonary embolic source when isolated thrombosis of
the large soleal vein was more than 7 mm in diameter. Soleal veins were the most
frequent and important location of calf DVT, suggesting that these were an
occasional embolic source of critical PE.
PMID- 9756429
TI - Homocysteine associated hypercoagulability and disseminated thrombosis--a case
report.
AB - The authors report the occurrence of vascular occlusion due to
hyperhomocysteinemia without significant underlying atherosclerotic disease. This
unique observation supports the potential of hyperhomocysteinemia to induce
thrombosis and the independence of the thrombosis from hyperhomocysteinemia's
associated atherosclerosis. The case demonstrates the clinical relevance of the
effects of hyperhomocysteinemia on the coagulation cascade. A 42-year-old woman
who lacked signs of classic homocystinuria developed disseminated thrombosis with
a 24-hour urine homocysteine concentration of 384 mg, twelve times the upper
limit of normal. Thrombosis was present in the aortic arch and its major branches
and in the mesenteric arteries and veins. A fatal stroke resulted from the
thrombosis. Autopsy revealed minimal atherosclerotic disease and no complicated
plaques. This case demonstrates an expanded role of hyperhomocysteinemia in
clinically significant vascular occlusion. Serum homocysteine concentration
determination may be a factor in the evaluation of a hypercoagulable state.
Hyperhomocysteinemia should be considered when evaluating arterial or venous
thrombosis in a young person regardless of whether atherosclerosis or other signs
of abnormal homocysteine metabolism are present.
PMID- 9756430
TI - Bilateral fistulas from the internal mammary arteries and the bronchial arteries
to the pulmonary arteries--a case report.
AB - A 78-year-old man was admitted to hospital with heart failure and chronic
bronchitis. A computed tomographic scan of the chest incidentally demonstrated
bilateral abnormal vessels near the left atrium. Selective angiography showed
that both internal mammary arteries and bronchial arteries communicated with the
pulmonary arteries bilaterally. The patient refused surgery and was discharged on
medical therapy. This is the first reported case of bilateral fistulas between
the internal mammary arteries and bronchial arteries and the pulmonary arteries.
PMID- 9756431
TI - Long-term follow-up of severe central serous chorioretinopathy using indocyanine
green angiography.
AB - BACKGROUND: The severe types of central serous chorioretinopathy (CSC) have a
chronic nature, suggesting that a pathological process persists subclinically.
Indocyanine green (ICG) angiography recently revealed intrachoroidal dye leakage
and its static nature in CSC. As the intrachoroidal dye leakage was suspected to
be relevant to the disease process, the long-term persistence of intrachoroidal
ICG leakage was examined in four patients of the severe types of CSC. METHODS:
ICG angiography was performed periodically over more than three years in three
patients and two years in one patient. One patient had CSC with bullous retinal
detachment, and the other three had chronic CSC or diffuse retinal pigment
epitheliopathy. RESULTS: Intrachoroidal ICG leakage persisted in all the
patients. However, a change in location of persistent intrachoroidal leakage or
disappearance of intrachoroidal leakage regardless of no progression of retinal
pigment epithelial alteration was noted in one eye of two patients. CONCLUSIONS:
Pathology causing intrachoroidal ICG leakage persisted subclinically for a long
period. However, location and extent of the intrachoroidal leakage could change
during a long-term follow-up period.
PMID- 9756433
TI - Evaluation of laser sclerostomy fistulas using ultrasound biomicroscopy.
AB - BACKGROUND: Laser sclerostomy is a relatively new technique in glaucoma surgery.
Clinical examination, particularly of the intrascleral part of laser sclerostomy
fistulas, is difficult. We performed ultrasound biomicroscopy (UBM) in order to
determine, if it were possible to visualize fistulas. Moreover, it was the aim to
investigate whether this imaging technique could provide additional information
on fistula morphology. PATIENTS AND METHODS: Ten eyes of eight patients with
chronic open angle glaucoma who had undergone erbium-YAG laser sclerostomy ab
externo were examined using a UBM-probe with a 20 MHz transducer providing
spatial resolution of approximately 80 microm. RESULTS: Radial scanning allowed
visualization of the sclerostomy fistula in nine of ten eyes. The different
functional state of sclerostomy fistulas correlated well to UBM findings. It was
possible to image differences in the morphology of occluded and patent fistulas
and to visualize the filtering pathway in functioning blebs. CONCLUSIONS:
Ultrasound biomicroscopy allows imaging of laser sclerostomy fistulas. UBM and
clinical findings correlated well in the majority of the patients we examined.
The technique supplements clinical examination and in some cases may provide
additional information.
PMID- 9756432
TI - Ocular sarcoidosis in Kuwait with a review of literature.
AB - OBJECTIVE: To study 18 cases of sarcoidosis, the hall mark of which was uveitis.
SETTING: Referrals from peripheral eye clinics. PATIENTS: 18 patients with
bilateral almost symmetric uveitis, negative Mantoux test and positive gallium
scan were enrolled in the study. Preliminary bronchoscopy and bronchial lavage
were not done due to social habits. RESULTS: Age ranged between 7-48 years with
median 15 and mean 19 years. Although the patients were multinational, yet all of
them were residents of Kuwait. A father and son were affected within 8 months
period. 78% were strictly ocular, associated pulmonary and salivary gland
affection 11% each. Sole anterior uveitis was found in 28%, associated with
intermediate uveitis in 55% and with posterior in 16.6% of cases. Clinically
detectable dry eyes associated 33% of cases. All our patients developed glaucoma
which resolved with treatment of uveitis in 88% of them. Gallium uptake of the
eye balls was found in 22%, of the lacrimal glands (panda sign) in 67%, and of
the salivary glands or chest 11% each. Positive biopsy was found in 72%, 22% of
which was conjunctival. Chest X-ray and SACE were positive in 11%. 61% had
hypergammaglobulinaemia and all had negative ANA and RF. CONCLUSIONS: (1) 61% of
ocular sarcoidosis presented below sarcoid age. (2) Multinationality together
with father's and son's affection indicate a climatic or environmental insult in
an already predisposed person. (3) Routine chest X-ray and SACE may not be
adequate for diagnosis of ocular sarcoidosis. Gallium should be done in suspected
cases. (4) Follow-up for prospects is emphasized.
PMID- 9756434
TI - Intravenous acyclovir treatment for extensive herpetic keratitis in a liver
transplant patient.
AB - Herpetic infection is a common complication among immune suppressed patients
following heart, kidney and bone marrow transplantations, in leukemia patients,
in AIDS patients, and during treatment with cytotoxic drugs. In the cases
described in the literature, oral acyclovir was recommended as a treatment for
the acute infection, as well as for prophylaxis. Intravenous acyclovir is not a
routine treatment for herpetic keratitis, but is recommended for cases of
insufficient clinical response to oral treatment, and defective absorption of
acyclovir by the gastrointestinal tract. We present a patient who underwent 4
liver transplantations, was treated regularly with immunosuppressive drugs, and
who developed extensive herpetic keratitis. The keratitis was resistant to both
topical ointment and oral acyclovir treatment. Recovery was only achieved
following the intravenous administration of acyclovir. We recommend intravenous
acyclovir treatment at a very early stage for immune suppressed patients with
extensive herpes simplex keratitis.
PMID- 9756435
TI - Ocular echography in the prognosis of vitreous haemorrhage in type II diabetes
mellitus.
AB - PURPOSE: In this study, we have attempted to demonstrate the presence of various
echographic parameters which could be associated with a non-spontaneous
resorption of vitreous haemorrhage in type II diabetes mellitus and correlate
these parameters with clinical outcome. SUBJECTS AND METHODS: We studied 297 eyes
of 257 patients with diabetic retinopathy and vitreous haemorrhage without
tractional macular retinal detachment ophthalmoscopically and echographically. Of
the total eyes studied, a 3-month follow-up visit (including ultrasound) was
available in 208 eyes. We retrospectively reviewed the medical records of each
patient. RESULTS: The echographic parameters associated with non-resorption of
the vitreous haemorrhage were: extramacular tractional retinal detachment,
fibrovascular membranes and location of the haemorrhage within the subhyaloidal
space (in contrast to within the intragel space). In addition, the duration of
the vitreous haemorrhage and the presence of panretinal laser photocoagulation at
the time of presentation with a vitreous haemorrhage influenced the resolution of
the vitreous haemorrhage. We were also able to construct a logarithmic function
that could be used to predict the prognosis of a vitreous haemorrhage in type II
diabetes mellitus. CONCLUSIONS: When employed to evaluate vitreous haemorrhages
in non-insulin-dependent diabetes mellitus, ocular ultrasound can provide useful
prognostic information regarding the lack of resorption of vitreous haemorrhages
in type II diabetics.
PMID- 9756436
TI - Profiling of human leukocyte antigens in Eales' disease.
AB - Eales' disease is a primary retinal perivasculitis of an undetermined etiology
seen predominantly in the Indian subcontinent and rarely in the West. Strong HLA
association has been proven in retinal vasculitis of Behcet's disease. HLA
association of Eales' disease is unknown and therefore the present study was
undertaken to determine the same. The frequency of 30 HLA antigens (9 HLA-A
antigens, 10 HLA-B antigens, 3 HLA-C antigens, 7 HLA-DR antigens and 1 HLA-DQ
antigen) was studied by standard micro-lymphocytotoxicity test in 57 patients
with Eales' disease and 50 age and sex-matched normal persons as controls. Both
the patients and controls underwent complete ocular and clinical examinations and
laboratory investigations. Inflammatory diseases similar to Eales' disease were
ruled out in the patients before they were enrolled. Statistically significant
higher phenotype frequencies of HLA B5 (B51), DR1 and DR4 were observed among
patients with Eales' disease as compared to controls. The gene frequency of HLA
B5 (B51) in our group of patients and controls was comparable with other earlier
studies in the Indian population. The finding of significant association of
Eales' patients with positive disequilibrium ( ) haplotypes A3-B44 and A11-B12
may be related to the development of this disease. The presence of the above HLA
antigens may be indicative of predisposition to Eales' disease.
PMID- 9756438
TI - LASIK: management of common complications. Laser in situ keratomileusis.
AB - PURPOSE: To review common complications noted with LASIK. METHODS: Review of
personal experience of the author with the procedure and work published in the
literature. RESULTS: The most common complications of the LASIK procedure include
flap irregularities, epithelium and other materials within the lamellar
interface, irregular astigmatism, regular astigmatism, regression, and
overcorrection. Infection is a rare but potentially serious complication.
CONCLUSIONS: LASIK has impressive potential for the correction of myopia and
hyperopia. Surgeons who perform the procedure must be familiar with recognition
and treatment of potential complications of LASIK.
PMID- 9756437
TI - Analysis of 24,444 surgical specimens accessioned over 55 years in an ophthalmic
pathology laboratory.
AB - PURPOSE: To summarize the pathologic diagnoses of a large number of surgically
obtained specimens over an extended time period in a single ophthalmic pathology
laboratory. METHODS: We analyzed the records of 24,444 surgically obtained
specimens accessioned in the L.F. Montgomery Ophthalmic Pathology Laboratory,
Emory University, Atlanta, GA between May 1941 and December 1995. Age, sex,
topography, clinical procedure, and histologic diagnosis were entered into a
database using the modified SNOMED coding system. The diagnosis of the surgically
enucleated eyes were analyzed with respect to years of enucleation. RESULTS: The
most common topographic area associated with a histologic diagnosis was the
cornea (39.3%), followed by lens (16.0%), vitreous (12.0%), uvea (9.8%), eyelids
(8.0%), conjunctiva (7.7%), retina (7.7%), and orbit (2.1%). The relative
proportion of vitreous specimens has continuously increased and became the most
common surgical specimen in 1995. The most common underlying disease of
surgically enucleated eyes is trauma (40.9%), followed by ocular neoplasia
(24.2%), 'surgical' diseases of the cornea, lens and retina including glaucoma
(17.3%), vascular diseases (6.7%), and inflammatory conditions (6.7%). The
relative frequency of trauma and ocular inflammation as a cause of enucleation
decreased significantly (p < 0.05) over the time of the study period while the
relative proportion of ocular neoplastic processes increased (p < 0.0001).
CONCLUSIONS: The availability of new surgical techniques has caused a change in
the relative frequencies of different ocular specimens submitted for histologic
examination.
PMID- 9756439
TI - Changing indications for penetrating keratoplasty: histopathology of 1,250
corneal buttons.
AB - PURPOSE: To analyze recent trends in the indications for penetrating
keratoplasty. METHODS: After keratoplasty, 2,557 corneal buttons were sent to and
analyzed in the ophthalmopathology laboratory of the University of Erlangen
Nurnberg, Erlangen, Germany, between 1992 and 1996. Of these, 1,250 random
corneal buttons were evaluated in this study. RESULTS: Histopathologic diagnoses
were (a) keratoconus (20.9%), (b) corneal scarring after keratitis/trauma
(20.4%), (c) pseudophakic/aphakic bullous keratopathy (17%), (d) regraft (15.5%),
(e) Fuchs' corneal endothelial dystrophy (14.9%), (f) necrotizing/ulcerative
keratitis (5.3%), and (g) corneal dystrophies (1.7%). CONCLUSION: Compared with a
previous report from our laboratory (1964-1986), the relative frequencies of
pseudophakic/aphakic bullous keratopathy, regraft, and Fuchs' dystrophy
increased, whereas corneal scarring decreased. Keratoconus is now the most
frequent indication for penetrating keratoplasty.
PMID- 9756440
TI - Morphological and fluorophotometric analysis of the corneal endothelium after
radial keratotomy.
AB - PURPOSE: To evaluate the morphometric and fluorophotometric characteristics of
corneal endothelium after an eight-incision radial keratotomy (RK). METHODS: A
total of 43 eyes of 26 patients underwent RK and 44 eyes of 23 patients were used
as age-matched controls. All patients underwent specular microscopic and
fluorophotometric examinations. Endothelial cell density [(ECD), cells/mm2], mean
cell area [(MCA), microm2], coefficient of variation (CV) for cell area, and
percentage (%) of hexagonal cells were measured by specular microscopy. Cornea-to
anterior chamber transfer coefficient (kc.ca, 10(-3) min(-1)) and corneal
endothelial permeability (10(-4) cm/min) were measured by fluorophotometry.
RESULTS: Morphometric and fluorophotometric characteristics were similar in both
the RK and control groups. Among patients in the RK group, the size of optical
zone and the depth of corneal incision did not affect postoperative endothelial
morphology or permeability. Those who presented for postoperative examination
later than 3 months compared with those presented within 3 months of RK had lower
CV for cell area; 0.28 +/- 0.04, 0.23 +/- 0.04, and 0.23 +/- 0.03, a higher
percentage of hexagonal cells; 64.7 +/- 8.0, 71.7 +/- 7.8, and 72.2 +/- 6.5, and
lower permeability; 5.7 +/- 1.9. 4.5 +/- 0.9, and 5.2 +/- 1.1, at <3 months,
between 3 and 6 months, and >6 months after RK, respectively (all p < 0.05). In
the eight cases of anisometropia, the operated eyes had a lower ECD; 3,079 +/-
429, and 3,217 +/- 495, a higher MCA; 330.6 +/- 48.1 and 317.6 +/- 50.5, and a
higher endothelial permeability; 6.3 +/- 1.5 and 4.7 +/- 1.3 in the operated and
unoperated eyes, respectively, at 3.4 months after RK (p < 0.05). CONCLUSION: RK
induced a minimal acute and nonprogressive endothelial loss. The transient
increase in permeability within 3 months may be due to a reversible endothelial
dysfunction induced by RK.
PMID- 9756441
TI - Topographic pattern and apex location of keratoconus on elevation topography
maps.
AB - PURPOSE: To compare topography pattern and apex location in elevation and axial
curvature topographic maps of keratoconic corneas. METHODS: We prospectively
evaluated 72 corneas of 42 patients who had one or more corneal findings of
keratoconus with the elevation and axial curvature displays of the PAR Corneal
Topography System (PAR-CTS) and 66 of these corneas with the axial curvature
display of the Tomey Topographic Modeling System (TMS-1). Topography maps were
evaluated for topography pattern and location of the cone apex. RESULTS: Axial
curvature displays of the PAR-CTS and the TMS-1 showed good concordance in terms
of topographic patterns (96% for right, 86% for left corneas) and apex locations
of cones (92% for right, 80% for left corneas). On the other hand, low
concordances were noted when comparing topographic patterns (35.3% for right,
36.8% for left corneas) and apex locations (47% for right, 38% for left corneas)
on curvature and elevation mode displays of PAR-CTS. Apices were found in the
inferotemporal quadrant in 65% of corneas evaluated with the PAR-CTS. This
distribution is significantly different from the apex location in axial curvature
maps (p < 0.04). Twenty-nine percent of corneas that showed an apex on the axial
curvature mode of the PAR-CTS had a normal pattern, without a detectable cone
apex, on the elevation mode display. CONCLUSIONS: The results of this study
clearly show the difference between elevation and curvature-based corneal
topographic evaluation of keratoconus. Unlike axial curvature maps, the majority
of apices on elevation maps are clustered in the inferotemporal quadrant. This
new information about apex location in keratoconic corneas provided by elevation
topography may have better diagnostic specificity than regional differences of
curvature on axial curvature maps. Because elevation mapping shows the physical
location of the cone, it may improve results of contact lens fitting and surgical
management.
PMID- 9756442
TI - Normal human corneal cell populations evaluated by in vivo scanning slit confocal
microscopy.
AB - PURPOSE: To analyze cellular populations in healthy human corneas. METHODS: The
study group consisted of 58 eyes of 45 patients with normal corneas. The age
distribution was 45 +/- 17 years (mean +/- SD; range, 20-84). Scanning slit
confocal microscopy of the central corneas was performed. The images were
analyzed visually for cell morphology, and the densities and areas of cells were
measured. RESULTS: No statistically significant differences were measured in cell
densities or cell areas of any corneal layer between female and male patients (p
= 0.22-0.50) nor between right and left eyes (p = 0.16-0.45). The area of
superficial epithelial cells was 913 +/- 326 microm2 (mean +/- SD; range, 518
2,112), and the superficial epithelial cell density was 1,213 +/- 370 cells/mm2
(mean +/- SD; range, 473-1,929). The area of basal epithelial cells was 177 +/-
19 microm2 (mean +/- SD; range, 138-242), and the basal epithelial cell density
was 5,699 +/- 604 cells/mm2 (mean +/- SD; range, 4,135-7,267). The average
apparent keratocyte density was 1,058 +/- 217 cells/mm2 (mean +/- SD; range, 604
1,599) in the anterior stroma, and 771 +/- 135 cells/mm2 (mean +/- SD; range, 493
1,145) in the posterior stroma. The difference in apparent keratocyte densities
between the anterior and posterior stroma was statistically significant (p <
0.001). The average endothelial cell area was 334 +/- 51 microm2 (range, 273
553), and the cell density was 3,055 +/- 386 cells/mm2 (mean +/- SD; range, 1,809
3,668). The endothelial cell density had a negative, statistically significant
correlation with age (r = -0.68, p < 0.001). The densities of the other corneal
cell layers did not have a statistically significant correlation with age.
CONCLUSION: In vivo scanning slit confocal microscopy is a useful tool for
studying corneal cell populations. Central corneal cell densities were found to
decrease significantly with age only in the endothelium. For the first time in
human corneas using in vivo confocal microscopy, this study statistically
confirms a higher apparent number of keratocytes in the anterior stroma than in
the posterior stroma.
PMID- 9756443
TI - In vivo confocal microscopy of Fuchs' endothelial dystrophy.
AB - PURPOSE: The purpose of this study is to analyze in vivo confocal microscopic
findings of corneas with Fuchs' endothelial dystrophy. METHODS: Central corneas
of 17 eyes of 11 patients aged 41-86 years were examined using in vivo scanning
slit confocal microscopy after being diagnosed with Fuchs' endothelial dystrophy.
The cellular structure of the corneas was analyzed morphologically and
quantitatively and compared to control results from 22 healthy corneas. RESULTS:
Bullae were detected in the basal epithelial layer of one eye. Eight of 17 eyes
(47%) exhibited an abnormal Bowman's layer: diffuse bright reflection and absence
of nerves. Eleven eyes (65%) exhibited abnormal anterior stroma: lacunae and
diffuse increased light reflection due to edema. In 12 eyes (71%), lacunae or
dark bands 5-20 microm wide against increased background reflection were noted in
the posterior stroma. Descemet's membrane was thickened in all eyes. Dark bands
were detected in six eyes (35%). Guttae (137-1,231/mm2) 20-40 microm in diameter
were found in every endothelial cell layer. The mean endothelial cell count was
1,202 +/- 850 (cells/mm2 +/- SD; range, 0-2,735). There was a positive
correlation between endothelial cell counts obtained by specular microscopy and
those obtained by confocal microscopy (r = 0.95). CONCLUSION: In vivo confocal
microscopic findings of Fuchs' endothelial dystrophy are described for the first
time in a series of cases. Pathological changes in Fuchs' dystrophy were detected
in all corneal layers, more frequently in the posterior layers. Endothelial cell
counts obtained with confocal microscopy were statistically similar to those
obtained with standard specular microscopy.
PMID- 9756444
TI - The association between ocular cicatricial pemphigoid and rheumatoid arthritis.
AB - PURPOSE: To assess the pathogenesis, symptomatology, and severity of rheumatoid
arthritis (RA) in patient's with concomitant ocular cicatricial pemphigoid (OCP).
METHODS: We retrospectively analyzed the charts of eight patients seen at a
single institution between the years 1972 and 1997 with concomitant RA and OCP.
Patients with OCP secondary to medical therapy, radiation, or chemical burns, or
Stevens-Johnson syndrome were excluded. RESULTS: The female-to-male ratio was
7:1. All patients had positive serum rheumatoid factors and immunohistochemical
confirmation of OCP. The mean number of years of RA prior to OCP diagnosis was
19. The number of patients with stage II OCP was three of eight (37.5%). The
number of patients with stage III OCP was five of eight (62.5%). All patients had
radiologic evidence of degenerative joint disease and synovial thickening. All
eight patients had keratoconjunctivitis sicca, five of eight patients (62.5%) had
Sjogren's syndrome, and five of eight patients (62.5%) developed rheumatoid
cornea necrosis leading to corneal perforation. CONCLUSIONS: The implication
exists that RA and OCP may be linked via an immunologically mediated mechanism
and that patients with severe extraarticular symptoms associated with RA may be
more likely to develop OCP. Prompt recognition of overlying symptoms may
facilitate proper therapy for control of both diseases.
PMID- 9756445
TI - Photorefractive keratectomy using the summit SVS Apex laser with or without
astigmatic keratotomy.
AB - PURPOSE: The purpose of this study was to evaluate the results of myopic
photorefractive keratectomy (PRK) with or without astigmatic keratotomy (AK) for
different levels of intended correction by using the SVS Apex laser. METHODS:
This is a retrospective cohort study of 226 eyes that had PRK for myopia ranging
from -1.0 to -7.6 diopters and 6 months of follow-up. In addition, 64 of these
eyes had AK for naturally occurring or laser-induced astigmatism. Uncorrected
visual acuity, spectacle-corrected visual acuity, and corneal topography with
quantitative descriptors of surface regularity (SRI) and surface asymmetry (SAI)
were used to monitor the results of PRK with or without AK. RESULTS: At 6 months,
95.6% eyes had an uncorrected visual acuity of 20/40 or better, 90% eyes were
within +/-1.0 diopter of emmetropia, and 3.1% eyes lost two lines of best
corrected vision. No eyes lost more than two lines of best-corrected vision. Mean
refractive astigmatism was reduced, but mean SAI and SRI were increased, 6 months
after PRK. Uncorrected vision, best-corrected vision, and predictability
decreased, whereas SAI and SRI increased, with increasing attempted correction.
CONCLUSION: PRK, with or without AK, effectively reduced myopia in all eyes by 6
months after surgery. Predictability tended to decrease with increasing attempted
correction, even for eyes with relatively low to moderate myopia. PRK may induce
surface asymmetry and irregularity at 6 months, and these alterations tend to be
greater as the attempted correction increases.
PMID- 9756446
TI - Corneal astigmatism after scleral buckling surgery assessed by Fourier analysis
of videokeratography data.
AB - PURPOSE: To evaluate quantitatively the changes in corneal curvature, including
irregular astigmatism, after scleral buckling surgery for retinal detachment.
METHODS: In 29 eyes of 29 patients undergoing scleral explant surgery,
videokeratographic measurements were carried out before and 1 week, 1 month, and
3 months after surgery. Using Fourier harmonic analysis, dioptric data on mire
rings were decomposed into spherical, regular astigmatic, and irregular
astigmatic (decentration and higher order irregularity) components. RESULTS: The
irregular astigmatic component significantly increased at 1 week postoperatively
but returned to the preoperative level 1 month after surgery. The regular
astigmatism also displayed a transient increase up to 1 month after surgery. The
increases in regular astigmatism were significant in eyes that had scleral
buckling of < or =180 degrees but not in eyes with buckles extending >180
degrees. CONCLUSION: Changes in irregular astigmatism after retinal detachment
surgery were quantitatively evaluated. The scleral buckling surgery causes a
transient increase in irregular astigmatism as well as regular astigmatism.
PMID- 9756447
TI - Comparison of three computerized videokeratoscopy systems with keratometry.
AB - PURPOSE: To compare the reproducibility of computerized videokeratoscopy systems
by using normal eyes and calibrated objects. METHODS: We evaluated the
reproducibility of three commercially available videokeratoscopes [EyeSys,
TechnoMed C-Scan, and PAR Corneal Topography System (CTS)] with the manual
keratometer (Bausch & Lomb) by using calibration spheres and 10 normal subjects
(20 eyes). All videokeratoscopy and keratometer results were obtained by one
investigator (R.M.). Each eye and calibration sphere were submitted to 10 serial
examinations by using each system. The average K of all points within the central
3.0 mm of the topography systems (central 3.0 mm) was compared with the average K
of the manual keratometer. RESULTS: All videokeratoscopy systems correlated well
with each other and manual keratometry when accessing aspheric and spherocylinder
calibration balls. EyeSys central keratometry clinical results had the strongest
correlation with the average keratometry results at 35%, followed by PAR-CTS at
25% and C-Scan at 5%. Among the videokeratoscopy units, EyeSys and PAR-CTS had
the strongest correlation at 65%. The correlation between the TechnoMed C-Scan
and both the EyeSys and PAR-CTS systems was 25%. There was a statistically
significant difference (p < 0.05) between the systems when analyzing the results
obtained from clinical subjects. The average keratometry (K) difference of human
eyes between videokeratoscopy systems is <0.35 diopters (D) (p < 0.05), which may
be clinically significant. The average manual K reading (42.97 D) is
statistically significantly flatter (p < 0.05) than each of the videokeratoscopy
units (EyeSys = 43.49 D; PAR = 43.48 D; C-Scan = 43.83 D). Comparing the 10
measurements of each eye or calibration object in the same videokeratoscopy
system verified that the devices give reproducible results. The average standard
deviation (ASD) of the keratometer was 0.10 D. The ASD of the videokeratoscopy
units was 0.05 D for the EyeSys, 0.29 D for the PAR-CTS, and 0.31 D for the C
Scan systems. CONCLUSION: Based on this study, we should not assume that the
results of different topography systems can be interchanged in clinical studies.
PMID- 9756448
TI - Effect of norepinephrine on proliferation, migration, and adhesion of SV-40
transformed human corneal epithelial cells.
AB - PURPOSE: To determine the ability of norepinephrine to modulate proliferation,
adhesion, and migration of SV-40 transformed human corneal epithelial cells.
METHODS: Assays were performed using SV-40 transformed human corneal epithelial
cells. For proliferation assays, cells were plated in 96-well plates coated with
fibronectin and collagen (FNC). A dose-response curve was generated for
norepinephrine in concentrations of 100 nM-100 microM. The cell number in each
well was evaluated using the fluorochrome Calcein AM (an intracellular esterase
cleavage substrate), and fluorescence was determined using an automated
fluorescent plate reader. For cell adhesion, 25 x 10(-3) cells were plated onto
FNC-coated 96-well plates, incubated in 10 nM-100 microM norepinephrine for 90
min, gently irrigated, and the remaining adherent cells quantitated. Cell
migration was measured using blind-well migration chambers with a 10-microm pore
size and FNC-coated filters. Cells (250 x 10(3)) were added to the upper chamber,
incubated for 18 h in the presence of factors, after which time the cells that
had migrated through the filter were quantitated. The toxicity of norepinephrine
was evaluated using a standard Live/Dead assay employing the combined
fluorochromes of ethidium homodimer (to indicate dead cells) and Calcein AM (to
indicate viable cells). Varying concentrations of norepinephrine were added, and
the cells incubated for 3 h and the fluorometric assay performed. RESULTS:
Norepinephrine stimulated corneal epithelial cell proliferation and migration
over a wide range of concentrations. It did not modulate cell adhesion and
demonstrated cell toxicity only at the highest (supraphysiologic) concentration
tested. CONCLUSIONS: Norepinephrine is normally found in the cornea and may be
important in the maintenance of normal corneal homeostasis and in wound-healing
processes.
PMID- 9756449
TI - Interlacing and cross-angle distribution of collagen lamellae in the human
cornea.
AB - PURPOSE: The interlacing and cross angles between the collagen lamellae within
the human corneal stroma were studied by means of scanning electron microscopy
(SEM). METHODS: For SEM, cells and noncollagenous extracellular matrix were
removed with 10% sodium hydroxide. Transmission electron microscopy (TEM)
preparations were performed according to standard procedures. The interlacing of
lamellae was studied within the limbal, paracentral, and central regions of five
different layers. The cross angles between the longitudinal axes of adjacent
lamellae were measured. The distribution of these angles within defined layers
and regions was compared. Special attention was paid to the interlacing of the
lamellae. RESULTS: Lamellae split in an anteroposterior direction as well as
horizontally into branches and are interlaced by crossing the fissures between
the branches. Smaller lamellae cross through clefts of neighboring lamellae. The
cross angles show a high variability of 1 degree - 90 degrees. With the exception
of the limbal region of the layer adjacent to Descemet's membrane, the
distribution of cross angles is similar. A frequent occurrence of cross angles
<30 degrees (68%) in this limbal layer can be explained by a pseudocircular
orientation (ligamentum circulare corneae) of the lamellae. CONCLUSION: The
present study shows that the three-dimensional organization of the collagen
lamellae is characterized by a greater extent of lamellar interlacing than has
been assumed until now.
PMID- 9756450
TI - Characterization of specular "dark events" in human donor corneal endothelium by
scanning and transmission electron microscopy.
AB - PURPOSE: To evaluate changes in the donor corneal endothelium in the intact globe
and in the in vivo rabbit cornea to characterize more fully the formation of
"dark events" without relief images in the endothelial mosaic. METHODS: Six ex
vivo human donor corneas in the intact globe and an in vivo rabbit model were
used to assess the morphological changes associated with osmotically increasing
fluid movement from the anterior chamber into the stroma by specular (SM),
confocal (CM), and transmission and scanning electron microscopy (TEM, SEM).
RESULTS: After application of hyperosmotic solution on the anterior surface of
the cornea, dark events without relief images were observed by SM and CM. In both
human and rabbit corneas, SEM showed that apical pores at the Y-junctions between
endothelial cells became enlarged. Large subendothelial spaces were observed on
Descemet's membrane by TEM with some spaces communicating with the anterior
chamber. CONCLUSIONS: The findings suggest that these openings at the Y-junctions
may represent intercellular channels that may also act as pathways for the
formation of intercellular and subendothelial vacuoles in both the rabbit and
human donor corneal endothelium. By virtue of their location, these vacuoles are
characterized by lack of relief images as seen with the contact SM.
PMID- 9756451
TI - Efficacy of cobalt chelates in the rabbit eye model for epithelial herpetic
keratitis.
AB - PURPOSE: A new class of antiviral agent, cobalt chelates (the CTC series), was
evaluated for treating epithelial herpetic keratitis, consequent stromal disease
being the major infectious cause of blindness in industrial nations. METHODS:
Effects of CTC complexes were monitored in cell cultures and in a rabbit eye
model, either infected with herpes simplex virus type 1 (HSV-1) or uninfected.
Several antiviral concentrations of CTC complexes nontoxic to Vero cells were
administered to rabbit eyes with HSV-1-induced keratitis. Corneal surface virus
titers were measured, and corneal lesions of epithelial keratitis were monitored
by slit-lamp microscopy and scored. Recovery rates and incidence were compared in
eyes treated with CTC complexes, placebo, or clinically formulated
trifluorothymidine (Viroptic), using nonparametric statistics. RESULTS: All CTC
complexes inhibited HSV-1 replication in vitro, CTC-96 being best. CTC-96, CTC
23, and CTC-67 eliminated (<1 plaque-forming unit[pfu]) corneal surface HSV-1
(otherwise >10(5) pfu) in order of descending potency, but CTC-82 was
ineffective. CTC-96 (either 5 microg/ml six times daily or 10 microg/ml five
times daily) accelerated herpetic dendritic keratitis recovery better than or the
same as trifluorothymidine (10 mg/ml nine times daily). CTC complexes were
nontoxic to Vero cells continuously exposed to < or =25 microg/ml; 50 microg/ml
of CTC 96 nine times daily did not irritate uninfected rabbit eyes. CONCLUSION:
Topical CTC-96 applications were at least as effective as Viroptic in diminishing
disease signs and corneal surface virus at concentrations less than one
thousandth that of Viroptic.
PMID- 9756453
TI - Pterygium with granuloma faciale-like histologic picture.
AB - PURPOSE: Description of a case with an atypical conjunctival pterygium with an
unusual histologic picture suggesting granuloma faciale, a vasculitis-like
disease of facial skin with a chronic, indolent course. Discussion of diagnosis
and treatment. METHODS: Repeated clinical and histologic observations. RESULTS: A
pterygium with an unusual nasosuperior localization was excised and examined
microscopically. There was a dense vessel-related inflammatory infiltrate,
essentially identical to granuloma faciale. The lesion recurred and, as granuloma
faciale is amenable to dapsone (diphenyl sulfone), treatment with 100 mg daily
resulted in rapid improvement, whereas reduction of the dose to 50 mg daily
resulted in relapse. Reinstitution of the original dose resulted in normalization
of the histologic picture. However, a recurrent pterygium developed, which had a
quite unspecific histologic picture. CONCLUSION: A disease with a histologic
picture essentially identical to granuloma faciale may manifest itself as a
pterygium. Treatment with dapsone may be beneficial.
PMID- 9756452
TI - Nosocomial Klebsiella pneumoniae conjunctivitis resulting in infectious keratitis
and bilateral corneal perforation.
AB - PURPOSE: Klebsiella pneumoniae is a known cause of metastatic endophthalmitis.
However, the organism has never been described to cause severe infectious
keratoconjunctivitis. We report a fulminant case of nosocomial K. pneumoniae
conjunctivitis complicated by infectious keratitis and corneal perforation in
both eyes. METHODS: An 83-year-old previously healthy Chinese woman, blind in the
right eye from rubeotic glaucoma and with bilateral dense cataracts, was admitted
for observation after a head injury. While in hospital, she developed purulent
bilateral conjunctivitis. Repeated cultures grew K. pneumoniae. This rapidly
progressed to severe infectious keratitis and corneal perforation in both eyes,
despite intensive antibiotics to which the organism was susceptible. The patient
was otherwise well, and investigations did not reveal any source of endogenous
sepsis. RESULTS: The patient lost complete vision in both eyes. The left eye
turned phthisical, and the right eye was eviscerated for uncontrolled
endophthalmitis. CONCLUSION: Although not previously reported, K. pneumoniae can
cause devastating keratoconjunctivitis resulting in corneal melt, perforation,
and uncontrolled endophthalmitis.
PMID- 9756454
TI - Recurrent Meesmann's corneal epithelial dystrophy after penetrating keratoplasty.
AB - PURPOSE: To characterize the histopathology of recurrent Meesmann's corneal
epithelial dystrophy after penetrating keratoplasty. METHODS: Postmortem
examination by light and electron microscopy of the eyes of an 84-year-old
patient with Meesmann's dystrophy who underwent a penetrating keratoplasty in the
right eye at age 74 years and a lamellar keratoplasty in the left eye at age 51
years. RESULTS: In the right eye, the characteristic features of Meesmann's
dystrophy were demonstrated in both the donor and recipient corneas. The
pathologic findings were limited to the corneal epithelium and included increased
thickness, architectural disorganization, loss of cell polarity, increased
amounts of intracellular glycogen, presence of intraepithelial microcysts
containing degenerated cells, and in some cells, the presence of an electron
dense fibrillogranular material associated with disrupted cytoplasmic filaments.
In the left eye, the corneal findings were consistent with but not specific for
Meesmann's dystrophy. These included architectural disorganization, loss of cell
polarity, presence of intraepithelial microcysts, and irregular thickening of the
basement membrane in the donor cornea. CONCLUSION: Meesmann's corneal epithelial
dystrophy is demonstrated to recur after penetrating keratoplasty. This finding
suggests that the abnormalities that lead to the disease are localized to the
corneal epithelial cells and not in the stroma, as previously proposed.
PMID- 9756455
TI - Multicenter drug study assessing in vitro antibiotic susceptibilities of ocular
isolates.
PMID- 9756456
TI - Trends in sexual risk behaviors among high school students--United States, 1991
1997.
AB - Each year, approximately three million cases of sexually transmitted diseases
(STDs) occur among teenagers, and approximately one million become pregnant.
Human immunodeficiency virus (HIV) infection is the sixth leading cause of death
among persons aged 15-24 years in the United States. Unprotected sexual
intercourse and multiple sex partners place young persons at risk for HIV
infection, other STDs, and pregnancy. To determine trends in sexual risk
behaviors among high school students, CDC analyzed data from the Youth Risk
Behavior Survey (YRBS) for the years 1991, 1993, 1995, and 1997. This report
summarizes the results of this analysis, which indicate that, from 1991 to 1997,
the percentage of U.S. high school students who had ever had sexual intercourse
decreased, and the prevalence of condom use among currently sexually active
students increased.
PMID- 9756457
TI - Epidemic typhoid fever--Dushanbe, Tajikistan, 1997.
AB - Typhoid fever, a severe systemic illness transmitted through food or water, is
caused by the bacterium Salmonella serotype Typhi. This report describes a major
epidemic of typhoid fever in Dushanbe, Tajikistan, that resulted from
contamination of the municipal water system. In Tajikistan, the Sanitary
Epidemiologic Service (SES) maintains records for reportable diseases. Dushanbe
(1997 population: 600,000) residents receive health care through assigned
polyclinics; surveillance for reportable diseases is based on polyclinic records.
A case of typhoid fever is defined as physician diagnosis or isolation of S.
Typhi from stool, blood, or urine cultures. In February 1997, a sudden increase
in the number of typhoid fever cases was identified by SES in Dushanbe, with
approximately 2000 cases registered during a 2-week period. In March, the
Ministry of Health of Tajikistan requested assistance from CDC. In collaboration
with local authorities and nongovernmental partners, CDC reviewed epidemiologic
and laboratory surveillance; conducted a case-control study to identify risk
factors for infection; and evaluated municipal drinking water quality, water
wastage, and health-education campaigns.
PMID- 9756458
TI - Influenza A--Florida and Tennessee, July-August 1998, and virologic surveillance
of influenza, May-August 1998.
AB - During July and August 1998, the state departments of health in Florida and
Tennessee each reported an outbreak of influenza. The Florida outbreak occurred
in July in two residential homes for children; the Tennessee outbreak occurred in
August among members of a family that vacationed together. This report summarizes
the investigation of these outbreaks, which were caused by influenza type A(H3N2)
viruses, and presents information on influenza isolates received by CDC during
May-August 1998, 81% of which were influenza A(H3N2).
PMID- 9756459
TI - Acquired multidrug-resistant tuberculosis--Buenaventura, Colombia, 1998.
AB - In 1996, the incidence of tuberculosis (TB) in Colombia was 26.5 per 100,000
population, and mortality was 3.4 per 100,000; in comparison, the incidence in
Buenaventura, a port town on the Pacific coast, was 90.5 per 100,000, and
mortality was 9.4 per 100,000. The prevalence of multidrug-resistant tuberculosis
(MDR-TB) (i.e., Mycobacterium tuberculosis isolates resistant to at least
isoniazid [INH] and rifampin [RIF]) was not known because susceptibility testing
is not performed routinely, and data on drug resistance for the country have not
been collected systematically. During October-November 1997, at the request of
the Secretary of Health in Cali, Colombia, the International Center for Training
and Medical Investigation in Cali performed sputum cultures for M. tuberculosis
and drug-susceptibility testing on isolates from 18 (75%) of 24 TB patients in
Buenaventura who were known to be clinically unresponsive to standard TB
treatment. MDR-TB was identified in 12 (67%) of these patients, four of whom
subsequently died. In March 1998, the International Center for Training and
Medical Investigation and the Secretary of Health of Colombia invited CDC to
participate in an investigation of these patients with MDR-TB. This report
summarizes the findings of this investigation, which indicated that
inconsistencies in treatment may have contributed to this outbreak, and provides
recommendations for the prevention and control of MDR-TB in Buenaventura.
PMID- 9756460
TI - Report on survey regarding collection and use of cause of injury data by states.
AB - In October 1997, the Injury Control and Emergency Health Services Section of the
American Public Health Association (APHA) conducted a survey of all 50 states,
the District of Columbia (DC), and Puerto Rico to assess the availability of
external cause-of-injury data in statewide hospital discharge data systems
(HDDS), hospital emergency department data systems (HEDDS), and other ambulatory
care data systems. The report on the findings of the analysis, How States are
Collecting and Using Cause of Injury Data, includes recommendations for improving
the quality and availability of statewide injury-related data for injury
prevention activities.
PMID- 9756461
TI - Development of Bacillus thuringiensis fermentation and process control from a
practical perspective.
AB - Bacillus thuringiensis (Bt) is the most widely used biopesticide producer in the
biological control market. It is very critical for the Bt pesticide industry to
be able to achieve a high yield in the Bt fermentation process in order to reduce
its cost and compete with chemical pesticides in the market. We review the
overall development of Bt fermentation process research and provide our point of
view for the future research opportunities and potential improvements. This
minireview covers the areas of fermentation physiology, growth dynamics and high
yield process control. It is pointed out that many studies aimed to improve spore
count and process research focusing on toxin protein yield is lacking. In
addition, significant development opportunities reside in the process development
for the genetically engineered Bt strains expressing multiple toxin proteins.
PMID- 9756462
TI - Degradation of human cardiac troponin I after myocardial infarction.
AB - Cardiac troponin I (TnI) is the inhibitory subunit of the troponin complex and a
specific biochemical marker for myocardial infarction (MI). It is released into
the bloodstream within 4-6 h following MI, peaks after 18-24 h and remains
elevated for up to 7 days. In this work, I have identified TnI forms present in
MI-patient serum. By immobilizing anti-TnI antibodies, which recognize various
epitopic sites on the TnI molecule, we were able to isolate TnI from MI-patient
serum pools. Western-blot analysis following SDS/PAGE shows two major TnI
fragments with apparent molecular masses of 18000 and 14000 Da. Either or both
fragments are seen in serum obtained from individuals with MI. The fragments are
generated as a result of proteolytic processing from the C-terminal region of
TnI. Partial processing from the N-terminal of TnI is also seen and is associated
with the generation of the 14000 Da fragment. Very little unprocessed intact TnI
is detected in patient serum after MI. The degradation in vitro of cardiac TnI
was studied by incubating either bovine or human recombinant TnI in serum.
Western-blot analyses with TnI antibody showed that purified TnI spiked into
normal human serum or MI-patient serum depleted of TnI degrades rapidly to lower
molecular mass fragments. Degradation of TnI is associated with a loss in
immunological activity. Serum TnI isolated by anti-TnI antibody, under non
dissociating conditions, is associated with at least troponin C (TnC) and
troponin T (TnT). This complex is bound by anti-TnI, anti-TnC and anti-TnT
antibodies.
PMID- 9756463
TI - An acidic glutaryl-7-aminocephalosporanic acid acylase from Pseudomonas
nitroreducens.
AB - A glutaryl-7-aminocephalosporanic acid (GL-7-ACA) acylase was purified 58-fold
from Pseudomonas nitroreducens in a two-step procedure involving osmotic shock
and carboxymethyl-Sepharose chromatography with a yield of 26%. The molecular
mass of the native enzyme was 58 kDa. SDS/PAGE revealed that it consisted of two
non-identical subunits with molecular masses of 35 and 21 kDa. The isoelectric
point of the purified enzyme was 5.3. The enzyme had an optimal pH of 5.5 and an
optimal temperature of 43 degrees C. The purified enzyme exhibited not only GL-7
ACA acylase activity but also gamma-glutamyltranspeptidase activity. The Km
values of the enzyme for GL-7-ACA and L-gamma-glutamyl p-nitroanilide were 10.41
mM and 5.92 microM respectively.
PMID- 9756464
TI - Surface-induced changes in the structure and activity of enzymes physically
immobilized at solid/liquid interfaces.
AB - A proteolytic enzyme, alpha-chymotrypsin, and a lipolytic enzyme, cutinase, were
adsorbed from aqueous solutions on solid surfaces with different hydrophobicities
and morphologies. With both enzymes the affinity of adsorption is larger for the
more hydrophobic surface. Water-soluble, flexible oligomers grafted on the
sorbent surface cause a decrease in enzyme adsorption. CD spectroscopy and
differential scanning calorimetry (DSC) indicate severe structural perturbations
in the enzymes resulting from adsorption. The CD spectra reflect an average of
the structure of the whole protein population. The DSC data allow additional
conclusions to be drawn on the heterogeneity in the conformational states of the
adsorbed enzymes. The degree of structural perturbation, that is the fraction of
the adsorbed molecules of which the structure is perturbed, is lower at a surface
that (1) is less hydrophobic, (2) contains water-soluble flexible oligomers and
(3) is more covered by the protein. The specific activities of the enzymes are
decreased on adsorption, more or less following the extent of structural
perturbation. Unlike in solution, in the adsorbed state the heat-induced
inactivation process is not identical with the heat-induced unfolding process.
Furthermore, when the enzymes are adsorbed their specific activities are much
less sensitive to temperature variation.
PMID- 9756465
TI - Immobilization of alpha-amylase on poly(vinyl alcohol)-coated perfluoropolymer
supports for use in enzyme reactors.
AB - The suitability and potential for the use of poly(vinyl alcohol) (PVA)-coated
solid perfluoropolymers in immobilized-enzyme engineering have been evaluated by
using alpha-amylase from Bacillus licheniformis for the hydrolysis of starch.
alpha-Amylase was covalently immobilized on PVA-coated poly(tetrafluoroethylene
hexafluoropropylene) (PVA-FEP) by covalent coupling with the use of p-beta
sulphate-(ethyl sulphonide)-aniline, 2,4,6-trichloro-1,3,5-triazine, 1.1'
carbonyldi-imidazole and 2,2, 2-trifluoroethanesulphonyl chloride activation
procedures, and also for comparison with cyanogen bromide-activated Sepharose 4B.
In all cases, immobilization greatly improved the thermostability of the alpha
amylase and its resistance to inactivation by 6 M urea. Also the enhancements of
enzymic activities with increased temperature were higher for the immobilized
enzymes than for the soluble enzyme, and the immobilized alpha-amylases were well
suited to the continuous hydrolysis of starch conducted at elevated temperatures.
Although the specific activities of the enzymes immobilized on PVA-FEP were lower
than for that immobilized to Sepharose 4B, these novel supports showed far
superior strength. The enzymes immobilized on PVA-FEP were able to be readily
recovered from stirred batch bioreactors for repeated reuse, whereas the enzymes
immobilized to Sepharose were fractured and fragmented under similar conditions
of stirring. A conventional fixed-bed bioreactor was found to be unsuitable for
continuous starch hydrolysis owing to an unacceptable build-up of pressure drop
across the bed. However, an expanded bed reactor containing alpha-amylase
immobilized on solid PVA-coated perfluorocarbon showed great potential for the
continuous hydrolysis of starch. Only 20% of the enzyme activity was lost after
use for 3 weeks at 72 degrees C. It is concluded that PVA-coated solid
perfluorocarbon is a highly promising support for use in immobilized enzyme
engineering.
PMID- 9756466
TI - Amplification of flow-microcalorimetry signal by means of multiple bioaffinity
layering of lectin and glycoenzyme.
AB - This paper demonstrates a positive influence of a special, stepwise technique of
enzyme immobilization based on the biospecific adsorption of the glycoenzyme
invertase on immobilized concanavalin A (Con A), subsequent adsorption of the
free Con A on the immobilized invertase:Con A support and repeated adsorption of
invertase on the support. A 3-fold repetition of the same procedure designed
preliminarily as bioaffinity layering afforded up to a 10-fold increase in
catalytic activity of the immobilized invertase. Reactive hydrogels based on bead
cellulose and bead poly(glycidyl methacrylate) were used as immobilization
supports for the preparation of these highly active preparations. The enhancement
in catalytic activity of immobilized invertase preparations was demonstrated
thermometrically, by flow microcalorimetry. Further attractive aspects for
utilizing the signal amplification of biosensors with immobilized enzymes are
discussed.
PMID- 9756467
TI - Expression of recombinant Lym-1 single-chain Fv in Escherichia coli.
AB - Lym-1 single-chain Fv (sFv) can be used for targeted radiodiagnosis and therapy
of B-lymphocytic malignancies. Lym-1 sFv was constructed and expressed as a
glutathione S-transferase fusion protein, using a (G4S)3 linker connecting the C
terminus of the VH domain and the N-terminus of the VL domain of Lym-1. Six
histidine residues and an E Tag epitope were introduced at the C-terminus of the
sFv. Lym-1 sFv was purified with glutathione-Sepharose 4B affinity chromatography
followed by digestion with thrombin. Lym-1 sFv of 28 kDa was confirmed by Western
blotting with anti-(E Tag) monoclonal antibody. An antigen binding assay of Lym-1
and a CD study indicated that it is functionally active.
PMID- 9756468
TI - Chromatographic removal and heat inactivation of hepatitis B virus during the
manufacture of human albumin.
AB - The purpose of the present study was to examine the efficacy of the
chromatographic and pasteurization steps, employed in the manufacture of human
albumin, in the removal and/or inactivation of hepatitis B virus (HBV). Most
human albumins manufactured today are prepared from donor plasma by fractionation
methods that use precipitation with cold ethanol. CSL Limited, an Australian
biopharmaceutical company, has recently converted its method of manufacture for
albumin from a traditional Cohn fractionation method to a method employing
chromatographic techniques. A step-by-step validation of virus removal and
inactivation was performed on this manufacturing process, which includes a DEAE
Sepharose(R) and CM-Sepharose(R) Fast Flow ion-exchange step, a Sephacryl(R) S200
High-Resolution gel-filtration step and a bulk pasteurization step where product
is held at 60 degreesC for 10 h. HBV partitioning experiments were conducted on
scaled-down chromatographic columns with hepatitis B surface antigen (HBsAg) as a
marker, whereas the HBV model virus, duck HBV, was used to study the inactivation
kinetics during pasteurization. Reductions for HBsAg through the three
chromatographic steps resulted in a total log10 decrease of 1.5 log10, whereas
more than 6.5 log10 decrease in duck HBV in Albumex(R)5 was achieved during
pasteurization.
PMID- 9756469
TI - alpha-Galactosidases of Penicillium simplicissimum: production, purification and
characterization of the gene encoding AGLI.
AB - Production of extracellular a-galactosidases by the filamentous fungus
Penicillium simplicissimum (previously P. janthinellum) VTT-D-78090 was studied
on different carbon sources. Steam-exploded oat husks were chosen as the best
carbon source for enzyme production. Three a-galactosidases (AGL) were purified
from the culture filtrate using ion-exchange chromatography, hydrophobic
interaction chromatography and gel filtration. The isoelectric points of AGLI,
AGLII and AGLIII were 5.2, 4.4 and 7.0, and the molecular masses as determined by
SDS/PAGE were 61, 84 and 61 kDa, respectively. All enzymes were glycosylated. The
optimum pH for the activity of AGLI and AGLIII was between 3.0 and 4.5 and that
of AGLII was between 4.0 and 5.0. AGLII was more stable and more resistant to
product inhibition by galactose than the other two enzymes. AGLI and AGLIII were
also inhibited by p-nitrophenol-a-D-galactopyranoside, the substrate used for
enzyme activity assay. The gene encoding AGLI was cloned and sequenced. The gene,
agl1, encodes 435 amino acids including the signal sequence. It showed similarity
with the other a-galactosidases belonging to the glycosyl hydrolase family 27.
The N-terminal amino acid sequence of AGLIII was also similar to the sequences of
other members of family 27, whereas the N-terminus of AGLII was completely
different from the sequences of other reported hydrolases.
PMID- 9756470
TI - An Arabidopsis mutant defective in the plastid general protein import apparatus.
AB - Elaborate mechanisms have evolved for the translocation of nucleus-encoded
proteins across the plastid envelope membrane. Although putative components of
the import apparatus have been identified biochemically, their role in import
remains to be proven in vivo. An Arabidopsis mutant lacking a new component of
the import machinery [translocon at the outer envelope membrane of chloroplasts
(Toc33), a 33-kilodalton protein] has been isolated. The functional similarity of
Toc33 to another translocon component (Toc34) implies that multiple different
translocon complexes are present in plastids. Processes that are mediated by
Toc33 operate during the early stages of plastid and leaf development. The data
demonstrate the in vivo role of a translocon component in plastid protein import.
PMID- 9756471
TI - Hepatitis C viral dynamics in vivo and the antiviral efficacy of interferon-alpha
therapy.
AB - To better understand the dynamics of hepatitis C virus and the antiviral effect
of interferon-alpha-2b (IFN), viral decline in 23 patients during therapy was
analyzed with a mathematical model. The analysis indicates that the major initial
effect of IFN is to block virion production or release, with blocking efficacies
of 81, 95, and 96% for daily doses of 5, 10, and 15 million international units,
respectively. The estimated virion half-life (t1/2) was, on average, 2.7 hours,
with pretreatment production and clearance of 10(12) virions per day. The
estimated infected cell death rate exhibited large interpatient variation
(corresponding t1/2 = 1.7 to 70 days), was inversely correlated with baseline
viral load, and was positively correlated with alanine aminotransferase levels.
Fast death rates were predictive of virus being undetectable by polymerase chain
reaction at 3 months. These findings show that infection with hepatitis C virus
is highly dynamic and that early monitoring of viral load can help guide therapy.
PMID- 9756472
TI - Mechanisms of directed attention in the human extrastriate cortex as revealed by
functional MRI.
AB - A typical scene contains many different objects, but the capacity of the visual
system to process multiple stimuli at a given time is limited. Thus, attentional
mechanisms are required to select relevant objects from among the many objects
competing for visual processing. Evidence from functional magnetic resonance
imaging (MRI) in humans showed that when multiple stimuli are present
simultaneously in the visual field, their cortical representations within the
object recognition pathway interact in a competitive, suppressive fashion.
Directing attention to one of the stimuli counteracts the suppressive influence
of nearby stimuli. This mechanism may serve to filter out irrelevant information
in cluttered visual scenes.
PMID- 9756473
TI - A structural basis for recognition of A.T and T.A base pairs in the minor groove
of B-DNA.
AB - Polyamide dimers containing three types of aromatic rings-pyrrole, imidazole, and
hydroxypyrrole-afford a small-molecule recognition code that discriminates among
all four Watson-Crick base pairs in the minor groove. The crystal structure of a
specific polyamide dimer-DNA complex establishes the structural basis for
distinguishing T.A from A.T base pairs. Specificity for the T.A base pair is
achieved by means of distinct hydrogen bonds between pairs of substituted
pyrroles on the ligand and the O2 of thymine and N3 of adenine. In addition,
shape-selective recognition of an asymmetric cleft between the thymine-O2 and the
adenine-C2 was observed. Although hitherto similarities among the base pairs in
the minor groove have been emphasized, the structure illustrates differences that
allow specific minor groove recognition.
PMID- 9756474
TI - A carrot leucine-rich-repeat protein that inhibits ice recrystallization.
AB - Many organisms adapted to live at subzero temperatures express antifreeze
proteins that improve their tolerance to freezing. Although structurally diverse,
all antifreeze proteins interact with ice surfaces, depress the freezing
temperature of aqueous solutions, and inhibit ice crystal growth. A protein
purified from carrot shares these functional features with antifreeze proteins of
fish. Expression of the carrot complementary DNA in tobacco resulted in the
accumulation of antifreeze activity in the apoplast of plants grown at greenhouse
temperatures. The sequence of carrot antifreeze protein is similar to that of
polygalacturonase inhibitor proteins and contains leucine-rich repeats.
PMID- 9756475
TI - Role for the target enzyme in deactivation of photoreceptor G protein in vivo.
AB - Heterotrimeric guanosine 5'-triphosphate (GTP)-binding proteins (G proteins) are
deactivated by hydrolysis of the GTP that they bind when activated by
transmembrane receptors. Transducin, the G protein that relays visual excitation
from rhodopsin to the cyclic guanosine 3',5'-monophosphate phosphodiesterase
(PDE) in retinal photoreceptors, must be deactivated for the light response to
recover. A point mutation in the gamma subunit of PDE impaired transducin-PDE
interactions and slowed the recovery rate of the flash response in transgenic
mouse rods. These results indicate that the normal deactivation of transducin in
vivo requires the G protein to interact with its target enzyme.
PMID- 9756476
TI - An antimicrobial activity of cytolytic T cells mediated by granulysin.
AB - Cytolytic T lymphocytes (CTLs) kill intracellular pathogens by a granule
dependent mechanism. Granulysin, a protein found in granules of CTLs, reduced the
viability of a broad spectrum of pathogenic bacteria, fungi, and parasites in
vitro. Granulysin directly killed extracellular Mycobacterium tuberculosis,
altering the membrane integrity of the bacillus, and, in combination with
perforin, decreased the viability of intracellular M. tuberculosis. The ability
of CTLs to kill intracellular M. tuberculosis was dependent on the presence of
granulysin in cytotoxic granules, defining a mechanism by which T cells directly
contribute to immunity against intracellular pathogens.
PMID- 9756477
TI - Harnessing the biosynthetic code: combinations, permutations, and mutations.
AB - Polyketides and non-ribosomal peptides are two large families of complex natural
products that are built from simple carboxylic acid or amino acid monomers,
respectively, and that have important medicinal or agrochemical properties.
Despite the substantial differences between these two classes of natural
products, each is synthesized biologically under the control of exceptionally
large, multifunctional proteins termed polyketide synthases (PKSs) and non
ribosomal peptide synthetases (NRPSs) that contain repeated, coordinated groups
of active sites called modules, in which each module is responsible for catalysis
of one complete cycle of polyketide or polypeptide chain elongation and
associated functional group modifications. It has recently become possible to use
molecular genetic methodology to alter the number, content, and order of such
modules and, in so doing, to alter rationally the structure of the resultant
products. This review considers the promise and challenges inherent in the
combinatorial manipulation of PKS and NRPS structure in order to generate
entirely "unnatural" products.
PMID- 9756479
TI - Enhanced positive cloud-to-ground lightning in thunderstorms ingesting smoke from
fires
AB - Smoke from forest fires in southern Mexico was advected into the U.S. southern
plains from April to June 1998. Cloud-to-ground lightning (CG) flash data from
the National Lightning Detection Network matched against satellite-mapped aerosol
plumes imply that thunderstorms forming in smoke-contaminated air masses
generated large amounts of lightning with positive polarity (+CGs). During 2
months, nearly half a million flashes in the southern plains exhibited +CG
percentages that were triple the climatological norm. The peak currents in these
+CGs were double the expected value. These thunderstorms also produced abnormally
high numbers of mesospheric optical sprites.
PMID- 9756478
TI - Tomographic evidence for localized lithospheric shear along the altyn tagh fault
AB - Seismic tomography across the Altyn Tagh fault, at the north edge of the Tibetan
Plateau, reveals a low P-wave velocity anomaly below the fault down to 140
kilometers. This anomaly probably reflects strike-slip shear in the lithosphere.
Slip-partitioning may also induce a wedge of crust from the Tarim Basin to plunge
into the mantle.
PMID- 9756480
TI - Triploblastic animals more than 1 billion years ago: trace fossil evidence from
india
AB - Some intriguing bedding plane features that were observed in the Mesoproterozoic
Chorhat Sandstone are biological and can be interpreted as the burrows of
wormlike undermat miners (that is, infaunal animals that excavated tunnels
underneath microbial mats). These burrows suggest that triploblastic animals
existed more than a billion years ago. They also suggest that the diversification
of animal designs proceeded very slowly before the appearance of organisms with
hard skeletons, which was probably the key event in the Cambrian evolutionary
explosion, and before the ecological changes that accompanied that event.
PMID- 9756481
TI - ROSAT X-ray detection of a young brown dwarf in the chamaeleon I dark cloud
AB - Photometry and spectroscopy of the object Cha Halpha 1, located in the Chamaeleon
I star-forming cloud, show that it is a approximately 10(6)-year-old brown dwarf
with spectral type M7.5 to M8 and 0.04 +/- 0.01 solar masses. Quiescent x-ray
emission was detected in a 36-kilosecond observation with 31.4 +/- 7.7 x-ray
photons, obtained with the Rontgen Satellite (ROSAT), with 9final sigma detection
significance. This corresponds to an x-ray luminosity of 2.57 x 10(28) ergs per
second and an x-ray to bolometric luminosity ratio of 10(-3.44). These are
typical values for late M-type stars. Because the interior of brown dwarfs may be
similar to that of convective late-type stars, which are well-known x-ray
sources, x-ray emission from brown dwarfs may indicate magnetic activity.
PMID- 9756482
TI - Measuring the spin polarization of a metal with a superconducting point contact
AB - A superconducting point contact is used to determine the spin polarization at the
Fermi energy of several metals. Because the process of supercurrent conversion at
a superconductor-metal interface (Andreev reflection) is limited by the minority
spin population near the Fermi surface, the differential conductance of the point
contact can reveal the spin polarization of the metal. This technique has been
applied to a variety of metals where the spin polarization ranges from 35 to 90
percent: Ni0.8Fe0.2, Ni, Co, Fe, NiMnSb, La0.7Sr0.3MnO3, and CrO2.
PMID- 9756483
TI - Particle nucleation in the tropical boundary layer and its coupling to marine
sulfur sources
AB - New particle formation in a tropical marine boundary layer setting was
characterized during NASA's Pacific Exploratory Mission-Tropics A program. It
represents the clearest demonstration to date of aerosol nucleation and growth
being linked to the natural marine sulfur cycle. This conclusion was based on
real-time observations of dimethylsulfide, sulfur dioxide, sulfuric acid (gas),
hydroxide, ozone, temperature, relative humidity, aerosol size and number
distribution, and total aerosol surface area. Classic binary nucleation theory
predicts no nucleation under the observed marine boundary layer conditions.
PMID- 9756484
TI - Synchronous climate changes in antarctica and the north atlantic
AB - Central Greenland ice cores provide evidence of abrupt changes in climate over
the past 100,000 years. Many of these changes have also been identified in
sedimentary and geochemical signatures in deep-sea sediment cores from the North
Atlantic, confirming the link between millennial-scale climate variability and
ocean thermohaline circulation. It is shown here that two of the most prominent
North Atlantic events-the rapid warming that marks the end of the last glacial
period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an
ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This
result contrasts with evidence from ice cores in other regions of Antarctica,
which show an asynchronous response between the Northern and Southern
Hemispheres.
PMID- 9756485
TI - Solution properties of single-walled carbon nanotubes
AB - Naked metallic and semiconducting single-walled carbon nanotubes (SWNTs) were
dissolved in organic solutions by derivatization with thionychloride and
octadecylamine. Both ionic (charge transfer) and covalent solution-phase
chemistry with concomitant modulation of the SWNT band structure were
demonstrated. Solution-phase near-infrared spectroscopy was used to study the
effects of chemical modifications on the band gaps of the SWNTs. Reaction of
soluble SWNTs with dichlorocarbene led to functionalization of the nanotube
walls.
PMID- 9756486
TI - Ammonia synthesis at atmospheric pressure
AB - Ammonia was synthesized from its elements at atmospheric pressure in a solid
state proton (H+)-conducting cell-reactor. Hydrogen was flowing over the anode
and was converted into protons that were transported through the solid
electrolyte and reached the cathode (palladium) over which nitrogen was passing.
At 570 degreesC and atmospheric pressure, greater than 78 percent of the
electrochemically supplied hydrogen was converted into ammonia. The thermodynamic
requirement for a high-pressure process is eliminated.
PMID- 9756487
TI - II. Alcoholic liver injury involves activation of Kupffer cells by endotoxin.
AB - It is well known that females show a greater susceptibility to alcohol-induced
liver injury than males. Additionally, females who consume alcohol regularly and
have been obese for 10 years or more are at greater risk for both hepatitis and
cirrhosis. Female rats on an enteral alcohol protocol exhibit injury more quickly
than males, with widespread fatty changes over a larger portion of the liver
lobule. Levels of plasma endotoxin, intercellular adhesion molecule-1, free
radical adducts, infiltrating neutrophils, and nuclear factor-kappaB are
increased about twofold more in livers from female than male rats after enteral
alcohol treatment. Estrogen treatment in vivo increases the sensitivity of
Kupffer cells to endotoxin. Evidence has been presented that Kupffer cells are
pivotal in the development of alcohol-induced liver injury. Destruction of
Kupffer cells with gadolinium chloride (GdCl3) or reduction of bacterial
endotoxin by sterilization of the gut with antibiotics blocks early inflammation
due to alcohol. Similar results have been obtained with anti-tumor necrosis
factor-alpha antibody. These findings led to the hypothesis that alcohol-induced
liver injury involves increases in circulating endotoxin, leading to activation
of Kupffer cells, which causes a hypoxia-reoxygenation injury. This idea has been
tested using pimonidazole, a nitroimidazole marker, to quantitate hypoxia in
downstream pericentral regions of the liver lobule. After chronic enteral
alcohol, pimonidazole binding increases twofold. Enteral alcohol also increases
free radicals detected with electron spin resonance. Importantly, hepatic hypoxia
and radical production detected in bile are decreased by destruction of Kupffer
cells with GdCl3. These data are consistent with the hypothesis that Kupffer
cells participate in important gender differences in liver injury caused by
alcohol.
PMID- 9756488
TI - Efficient hepatic uptake and concentrative biliary excretion of a mercapturic
acid.
AB - The role of the liver in the disposition of circulating mercapturic acids was
examined in anesthetized rats and in the isolated perfused rat liver using S-2,4
dinitrophenyl-N-acetylcysteine (DNP-NAC) as the model compound. When DNP-NAC was
infused into the jugular vein (150 or 600 nmol over 60 min) it was rapidly and
nearly quantitatively excreted as DNP-NAC into bile (42-36% of the dose) and
urine (48-62% of dose). Some minor metabolites were detected in bile (<4%), with
the major metabolite coeluting on HPLC with the DNP conjugate of glutathione (DNP
SG). Isolated rat livers perfused single pass with 3 microM DNP-NAC removed 72 +/
9% of this mercapturic acid from perfusate. This rapid DNP-NAC uptake was
unaffected by sodium omission, or by L-cysteine, L-glutamate, L-cystine, or N
acetylated amino acids, but was decreased by inhibitors of hepatic sinusoidal
organic anion transporters (oatp), indicating that DNP-NAC is a substrate for
these transporters. The DNP-NAC removed from perfusate was promptly excreted into
bile, eliciting a dose-dependent choleresis. DNP-NAC itself constituted
approximately 75% of the total dose recovered in bile, reaching a concentration
of 9 mM when livers were perfused in a recirculating mode with an initial DNP-NAC
concentration of 250 microM. Other biliary metabolites included DNP-SG, DNP
cysteinylglycine, and DNP-cysteine. DNP-SG was likely formed by a spontaneous
retro-Michael reaction between glutathione and DNP-NAC. Subsequent degradation of
DNP-SG by biliary gamma-glutamyltranspeptidase and dipeptidase activities
accounts for the cysteinylglycine and cysteine conjugates, respectively. These
findings indicate the presence of efficient hepatic mechanisms for sinusoidal
uptake and biliary excretion of circulating mercapturic acids in rat liver and
demonstrate that the liver plays a role in their whole body elimination.
PMID- 9756489
TI - Indomethacin increases susceptibility to injury in human gastric cells
independent of PG synthesis inhibition.
AB - Indomethacin and other nonsteroidal anti-inflammatory drugs are commonly used to
indirectly deduce the possible role of PGs in a process being studied. The
objective of this study was to determine if indomethacin, at concentrations
comparable to plasma and tissue levels obtained in humans taking therapeutic
doses, predisposes human gastric cells to injury through inhibition of PGs or
acts through an alternate mechanism. The role of intracellular Ca2+ in this
damaging process was also assessed. Indomethacin pretreatment, although by itself
nondamaging, was associated with elevated intracellular Ca2+ concentrations and
an increased cellular permeability, an effect that was dependent on extracellular
Ca2+. Furthermore, indomethacin pretreatment significantly predisposed AGS cells
to injury induced by two dissimilar agents (deoxycholate and A-23187), both of
which are associated with intracellular Ca2+ accumulation. The addition of
exogenous PGs did not reverse the predisposition to injury induced by
indomethacin. The observed effects of indomethacin were dependent on
concentration and not on ability to inhibit PG synthesis. Similar effects were
not observed with equipotent concentrations of ibuprofen or aspirin. Finally, the
exacerbation of deoxycholate-induced injury induced by indomethacin was not
observed when extracellular Ca2+ was removed. Indomethacin, by disturbing
intracellular Ca2+ homeostasis, predisposes human gastric cells to injury through
mechanisms independent of PG synthesis. The current study suggests that data
resulting from studies employing only indomethacin as a PG synthesis inhibitor
should be interpreted with caution.
PMID- 9756490
TI - Protein kinase G expression in the small intestine and functional importance for
smooth muscle relaxation.
AB - In functional experiments, the nitric oxide (NO) donor N-morpholino-N-nitroso
aminoacetonitrile or the cGMP analog 8-(4-chlorophenylthio)-cGMP caused a
concentration-dependent, tetrodotoxin-resistant relaxation of precontracted
strips from rat small intestine. The inhibitory effect of both substances was
completely blocked at lower concentrations and was significantly attenuated at
higher concentrations by the selective cGMP-dependent protein kinase (cGK)
antagonist KT-5823 (1 microM). cGK-I was identified by immunohistochemistry in
circular and longitudinal muscle, lamina muscularis mucosae, and smooth muscle
cells of the villi and in fibroblast-like cells of the small intestine.
Additionally, there was staining of a subpopulation of myenteric and submucous
plexus neurons. Double staining for neuronal NO synthase (nNOS) and cGK-I
demonstrated a colocalization of these two enzymes. Western blot analysis of
smooth muscle preparations and isolated nerve terminals demonstrated that these
structures predominantly contain the cGK-Ibeta isoenzyme, whereas the cGK-Ialpha
expression is about threefold less. The isoform cGK-II was entirely confined to
mucosal epithelial cells. These results show that cGK-I is expressed in different
muscular structures of the small intestine and participates in the NO-induced
relaxation of gastrointestinal smooth muscle. The presence of cGK-I in NOS
positive enteric neurons further suggests a possible neuronal action site.
PMID- 9756491
TI - Binding of [3H]palmitate to BSA.
AB - Determination of the BSA-palmitate high-affinity binding constant (Ka)
traditionally relied on the heptane-water partitioning technique. We used this
technique to calculate Ka for the BSA-[3H]palmitate complex, to determine if Ka
was independent of protein concentration, and to determine if the unbound
[3H]palmitate concentration is constant at different BSA concentrations using
constant BSA-to-palmitate molar ratios (range 1:1 to 1:4). After extensive
extraction of non-[3H]palmitate radiolabeled substances, the heptane-to-buffer
partition ratio, in the absence of BSA, was 702 +/- 19 (mean +/- SD, n = 6). This
value was much lower than the predicted value of 1,376 and was highly dependent
on which phase (organic or aqueous) initially contained the [3H]palmitic acid.
The data were consistent with the notion of self-association of [3H]palmitate in
the aqueous phase. Ka for the BSA-[3H]palmitate complex was determined to be
similar (2.2 +/- 0.1) x 10(8) M-1 (mean +/- SD, P > 0.05) at all BSA
concentrations studied. At each BSA-to-palmitate molar ratio, the equilibrium
unbound ligand concentration was constant only at low BSA concentrations (<10
microM) and at low BSA-to-palmitate molar ratios (i.e., 1:1 and 1:2). At higher
BSA concentrations and molar ratios, the unbound ligand concentration increased
with an increase in protein concentration. Hepatocyte uptake using the
manufacturer-supplied radiolabeled product was significantly higher than with the
purified product, suggesting that a non-[3H]palmitate radiolabel is also a
substrate for the uptake process.
PMID- 9756492
TI - Effect of feeding diets of varying fatty acid composition on apolipoprotein
expression in newborn swine.
AB - The purpose of this study was to determine the effect of chronic (1 wk) feeding
of dietary triacylglycerol (TG) of varying fatty acid composition on small
intestinal and hepatic apolipoprotein expression, as well as serum lipid and
apolipoprotein concentrations, in newborn swine. Two-day-old female swine were
fed one of three diets by gavage with the following lipid composition: medium
chain TG (MCT; MCT oil), intermediate-chain saturated TG (ICST; coconut oil), and
long-chain polyunsaturated TG (LCPUT; safflower oil) at 753 kJ . kg-1 . day-1
with 51% of energy from fat. After 1 wk, serum lipids and apolipoprotein
concentrations were measured, and jejunal apolipoprotein B (apo B) and apo A-I
mass and apo B, apo A-I, apo A-IV, and apo C-III synthesis were measured. Liver
was processed for determination of apo B and apo A-I mass and apo B, apo A-I, apo
C-III, and beta-actin mRNA abundance by slot blot hybridization. Compared with
the MCT and LCPUT groups, the ICST group had higher total serum cholesterol, TG,
high-density lipoprotein (HDL)-cholesterol, and apo A-I concentrations. There
were no differences among the three groups for intestinal apolipoprotein mass or
synthesis. In liver, apo A-I mass was highest in the ICST group. Liver apo A-I
and apo C-III mRNA abundance was highest in the ICST group. Among all three
groups, hepatic apo A-I mass correlated significantly with plasma HDL-cholesterol
concentrations, and serum TG concentrations correlated with hepatic apo C-III
mRNA abundance. In conclusion, we found that in the newborn piglet, chronic
feeding of ICST increases serum total cholesterol, TG, HDL-cholesterol, and apo A
I concentrations and hepatic expression of apo A-I and apo C-III mRNA, compared
with feeding of MCT or LCPUT. We speculate that increased hepatic apo A-I
expression may contribute to the higher serum HDL and apo A-I concentrations in
the ICST animals. Increased hepatic expression of apo C-III with ICST feeding may
contribute to the higher serum TG concentrations by apo C-III-mediated inhibition
of the catabolism of triacylglycerol-rich lipoproteins.
PMID- 9756493
TI - Uptake and metabolism of structured triglyceride by Caco-2 cells: reversal of
essential fatty acid deficiency.
AB - Structured lipids have been proposed as efficient vehicles for the
supplementation of essential fatty acids (EFA) to patients with malabsorption. We
investigated how a novel structured triglyceride (STG), containing purely
octanoic acid in the sn-1/sn-3 and [14C]linoleic acid in the sn-2 positions, was
incorporated into different lipid classes in Caco-2 cells. We also evaluated the
contribution of gastric lipase in the uptake and metabolism of [14C]linoleic acid
from the STG. We furthermore determined the potential of the STG to correct EFA
deficiency induced in Caco-2 cells. The absorption of STG by Caco-2 cells was
significantly greater compared with that of triolein. The addition of human
gastric lipase significantly enhanced cellular uptake of the labeled substrate,
reflecting the stereoselectivity of gastric lipase to hydrolyze medium chain FA.
Analysis of the intracellular lipids synthesized revealed a predominance of
phospholipids-monoglycerides. Most of the radioactivity in the lipoproteins
isolated from Caco-2 cells was recovered in TG-rich lipoproteins (45%) and to a
lesser extent in the high-density lipoprotein (36%) and low-density lipoprotein
(17%) fractions. The administration of STG to Caco-2 cells rendered EFA deficient
produced a marked increase of the cellular level of linoleic and arachidonic
acids. This resulted in a lower ratio of 20:3(n-9) to 20:4(n-6), reflecting the
correction of EFA deficiency in Caco-2 cells. Our data demonstrate that STG, in
the presence of gastric lipase, have beneficial effects on lipid incorporation,
lipoprotein production, and EFA status, utilizing Caco-2 cells as a model of EFA
deficiency.
PMID- 9756494
TI - Immunolocalization of gastrin-dependent histidine decarboxylase activity in rat
gastric mucosa during feeding.
AB - The localization of histidine decarboxylase (HDC) activity in the
enterochromaffin-like (ECL) cells of the oxyntic mucosa was studied during
fasting and refeeding using monoclonal (CURE no. 44178) and polyclonal (CURE no.
94211) antibodies directed against the COOH terminus of HDC (HDC-CT). Changes in
HDC immunostaining were correlated with mucosal HDC enzyme activity.
Immunoneutralization of circulating gastrin and atropine treatment during
refeeding were used to determine the relative importance of gastrin and
cholinergic mechanisms in the regulation of HDC activity and immunostaining.
Fasting caused a rapid reduction in the number of ECL cells immunostaining for
HDC that was correlated with an almost complete loss of mucosal HDC enzyme
activity. Refeeding restored both HDC immunostaining and enzyme activity within 2
4 h, and this response was inhibited by gastrin immunoneutralization but not by
atropine treatment. Immunostaining was uniformly decreased and restored in the
lower half of the oxyntic mucosa, which corresponds to the predominant area of
ECL cells in the gastric gland. Histamine immunostaining and mucosal histamine
content were not significantly changed during fasting and refeeding or by gastrin
antibody and/or atropine treatment during refeeding. These findings indicate that
HDC activity correlates with HDC-CT immunostaining and that both HDC activity and
HDC-CT immunostaining are regulated by gastrin during refeeding.
PMID- 9756495
TI - PYY stimulates synthesis and secretion of intestinal apolipoprotein AIV without
affecting mRNA expression.
AB - We tested whether exogenous peptide YY (PYY) can stimulate synthesis and
lymphatic secretion of intestinal apolipoprotein AIV (apo AIV). Rats with
mesenteric lymph fistulas and right atrial cannulas were given continuous
intravenous infusions of control vehicle or PYY at 25, 50, 75, 100, or 200 pmol .
kg-1 . h-1. PYY (75-200 pmol . kg-1 . h-1) stimulated lymphatic apo AIV output
from 1.5- to 3.5-fold higher than basal output. In separate experiments, PYY (100
pmol . kg-1 . h-1) produced a 60% increase in jejunal mucosal apo AIV synthesis
but had no effect on mucosal apo AIV mRNA levels at doses up to 200 pmol . kg-1 .
h-1. Finally, exogenous PYY infusion (100 pmol . kg-1 . h-1) produced a plasma
PYY increment of 30 pM compared with an increment of 18.7 pM in response to ileal
infusion of lipid. These results support the hypothesis that PYY may be an
endocrine mediator of the effects of distal gut lipid on production and release
of intestinal apo AIV, likely via a posttranscriptional mechanism of action.
PMID- 9756496
TI - Histamine sensitivity of mesenteric afferent nerves in the rat jejunum.
AB - The concept of functional interaction between mast cells and intestinal afferents
is gaining support. We have therefore characterized the action of histamine on
jejunal afferent discharge in the anesthetized rat. Whole nerve mesenteric
afferent discharge was recorded in conjunction with intestinal pressure in
response to a range of histamine agonists and antagonists. Histamine at 2, 4, and
8 micromol/kg (iv) evoked a dose-dependent biphasic increase in afferent
discharge together with a biphasic rise in intestinal pressure. However, these
two events were mediated independently, since nifedipine (1 mg/kg) substantially
reduced the intestinal pressure increase but not the afferent discharge. These
responses were completely inhibited by pyrilamine (5 mg/kg) but unaffected by
ranitidine (5 mg/kg) or thioperamide (2 mg/kg). Neither the selective H2 receptor
agonist dimaprit nor the selective H3 receptor agonist R-alpha-methylhistamine
caused any modulation of afferent discharge. We conclude that histamine
stimulates an H1 receptor-mediated increase in mesenteric afferent discharge that
is independent of intestinal motor events. This suggests that histamine
potentially acts as a mediator in mast cell-to-afferent nerve communication in
the small intestine.
PMID- 9756497
TI - Persistence of Helicobacter pylori VacA toxin and vacuolating potential in
cultured gastric epithelial cells.
AB - The vacuolating toxin A (VacA) is one of the most important virulence factors in
Helicobacter pylori-induced damage to human gastric epithelium. Using human
gastric epithelial cells in culture and broth culture filtrate from a VacA
producing H. pylori strain, we studied 1) the delivery of VacA to cells, 2) the
localization and fate of internalized toxin, and 3) the persistence of toxin
inside the cell. The investigative techniques used were neutral red dye uptake,
ultrastructural immunocytochemistry, quantitative immunofluorescence, and
immunoblotting. We found that VacA 1) is delivered to cells in both free and
membrane-bound form (i.e., as vesicles formed by the bacterial outer membrane),
2) localizes inside the endosomal-lysosomal compartment, in both free and
membrane-bound form, 3) persists within the cell for at least 72 h, without loss
of vacuolating power, which, however, becomes evident only when NH4Cl is added,
and 4) generally does not degrade into fragments smaller than approximately 90
kDa. Our findings suggest that, while accumulating inside the endosomal-lysosomal
compartment, a large amount of VacA avoids the main lysosomal degradative
processes and retains its apparent molecular integrity.
PMID- 9756498
TI - Inhibition of Na+/H+ exchange stimulates CCK secretion in STC-1 cells.
AB - It has been demonstrated that K+ channel regulation of membrane potential is
critical for control of CCK secretion. Because certain K+ channels are pH
sensitive, it was postulated that pH affects K+ channel activity in the CCK
secreting cell line STC-1 and may participate in regulating CCK secretion. The
present study examines the role of electroneutral Na+/H+ exchange on
extracellular acidification and hormone secretion. Treatment of STC-1 cells with
the amiloride analog ethylisopropyl amiloride (EIPA) to inhibit Na+/H+ exchange
inhibited Na+-dependent H+ efflux and increased basal CCK secretion. Substituting
choline for NaCl in the extracellular medium elevated basal intracellular Ca2+
concentration and stimulated CCK release. Stimulatory effects on hormone
secretion were blocked by the L-type Ca2+ channel blocker diltiazem, indicating
that secretion was dependent on the influx of extracellular Ca2+. To determine
whether the effects of EIPA and Na+ depletion were due to membrane
depolarization, we tested graded KCl concentrations. The ability of EIPA to
increase CCK secretion was inhibited by depolarization induced by 10-50 mM KCl in
the bath. Maneuvers to lower intracellular pH (pHi), including reducing
extracellular pH (pHo) to 7.0 or treatment with sodium butyrate, significantly
increased CCK secretion. To examine whether pH directly affects membrane K+
permeability, we measured outward currents carried by K+, using whole cell patch
techniques. K+ current was significantly inhibited by lowering pHo to 7.0. These
effects appear to be mediated through changes in pHi, because intracellular
dialysis with acidic solutions nearly eliminated current activity. These results
suggest that Na+/H+ exchange and membrane potential may be functionally linked,
where inhibition of Na+/H+ exchange lowers pHi and depolarizes the membrane,
perhaps through inhibition of pH-sensitive K+ channels. In turn, K+ channel
closure and membrane depolarization open voltage-dependent Ca2+ channels, leading
to an increase in cytosolic Ca2+ and CCK release. The effects of pHi on K+
channels may serve as a potent stimulus for hormone secretion, linking cell
metabolism and secretory functions.
PMID- 9756499
TI - Effects of chronic ethanol consumption on cytokine regulation of liver
regeneration.
AB - Ethanol ingestion may interrupt the proregenerative signal transduction that is
initiated by injury-related cytokines such as tumor necrosis factor (TNF)-alpha
and TNF-alpha- inducible cytokines including interleukin (IL)-6. To test this
theory, liver regeneration, TNF-alpha and IL-6 expression, and cytokine-regulated
prereplicative events were compared in ethanol-fed rats and isocalorically fed
controls after 70% partial hepatectomy (PH). Ethanol feeding inhibits hepatocyte
replication and recovery of liver mass after PH but generally promotes induction
of both cytokines in the liver and extrahepatic tissues (i.e., white adipose
tissue). Cytokine-regulated events that occur early in the prereplicative period
are influenced differentially. TNF-alpha-dependent increases in hepatic nuclear
factor-kappaB (NF-kappaB) p50 and p65 expression and DNA binding activity are
prevented, whereas IL-6-dependent inductions of hepatic Stat-3 phosphorylation
and DNA binding activity occur normally. In contrast, events (e.g., induction of
cyclin D1, cdk-1, cyclin D3, and p53 mRNA) that occur at the end of the
prereplicative period are uniformly inhibited. These findings indicate that
chronic ethanol ingestion arrests the regenerative process during the
prereplicative period and demonstrate that increased TNF-alpha, IL-6 and Stat-3
are not sufficient to assure hepatocyte proliferation after PH.
PMID- 9756500
TI - Src kinase and PI 3-kinase as a transduction pathway in ceramide-induced
contraction of colonic smooth muscle.
AB - Ceramide mediates sustained contraction of smooth muscle cells. C2 ceramide
induced a rapid increase in Src kinase activity within 15 s, peaked at 1 min, and
was sustained up to 8 min. Contraction and Src kinase activity were inhibited in
cells incubated in Ca2+-free medium containing 2 mM EGTA and in cells
preincubated with herbimycin A, a Src kinase inhibitor. Immunoblotting using a
phosphospecific anti-Src (416Y) antibody showed a ceramide-induced increase in
pp60(src) tyrosine phosphorylation. Immunoprecipitation using an anti
phosphotyrosine antibody followed by Western immunoblotting using a monoclonal
IgG anti-phosphoinositide 3-kinase NH2 terminal-SH2 domain antibody showed a
ceramide-induced increase in phosphoinositide 3-kinase (PI 3-kinase) tyrosine
phosphorylation at a protein mass corresponding to 85 kDa, the regulatory subunit
of PI 3-kinase, which contains the Src kinase binding site. PI 3-kinase
phosphorylation was inhibited by herbimycin A and by the PI 3-kinase inhibitors
wortmannin and LY-294002. Preincubation of cells with herbimycin A or PI 3-kinase
inhibitors also resulted in an inhibition of mitogen-activated protein (MAP)
kinase p42 and p44 activities as seen on Western blots. In summary, we found that
1) the maintenance of sustained contraction is dependent on extracellular Ca2+;
2) ceramide activates a nonreceptor tyrosine kinase pathway through activation of
pp60(src) and PI 3-kinase; and 3) the converging signals are probably through
activation of MAP kinase.
PMID- 9756501
TI - Monochloramine induced DNA fragmentation in gastric cell line MKN45.
AB - Monochloramine (NH2Cl) is known to be one of the virulence factors in
Helicobacter pylori-associated gastric mucosal injury. The present study was
designed to examine NH2Cl-evoked DNA fragmentation in the gastric epithelial cell
line MKN45. NH2Cl was produced by mixing NH3 with sodium hypochlorite (NaClO).
MKN45 cells were exposed to NH2Cl, NH3, or NaClO in Hanks' balanced salt
solution. DNA cleavage was evaluated quantitatively by photometeric enzyme
immunoassay for the in vitro determination of cytoplasmic mono- and
oligonucleosomes. Damage to the plasma membrane was assessed by measuring the
activity of lactate dehydrogenase in the supernatants. Separately, DNA ladder
formation was performed to confirm the incidence of DNA fragmentation. NH2Cl
(0.001-0.01 mM) significantly increased the cytoplasmic mono- and
oligonucleosomes, suggesting the incidence of DNA cleavage. The DNA ladder was
clearly evoked by NH2Cl. NH2Cl induced a DNA fragmentation, one of the important
aspects in apoptosis, in the gastric cell line MKN45.
PMID- 9756502
TI - Hepatocellular expression of glucose-6-phosphatase is unaltered during hepatic
regeneration.
AB - Gluconeogenesis and glycogenolysis are essential hepatic functions required for
glucose homeostasis. During the initial phase of hepatic regeneration, the
immediate-early genes (IEG) are rapidly expressed, and the IEG RL-1 encodes for
glucose-6-phosphatase (G-6-Pase). G-6-Pase is a microsomal enzyme essential for
gluconeogenesis and glycogenolysis. This study employs a partial-hepatectomy
model to examine the expression and activity of G-6-Pase. After partial
hepatectomy, rat hepatic G-6-Pase gene expression is transcriptionally regulated,
and mRNA levels are increased approximately 30-fold. However, in contrast to this
rapid gene induction, microsomal enzyme activity is unchanged after partial
hepatectomy. Western blotting demonstrates that microsomal G-6-Pase protein
expression is also unchanged after partial hepatectomy, and similar results are
also noted in whole liver homogenate. Thus, despite marked induction in gene
expression of the IEG G-6-Pase after partial hepatectomy, protein expression and
enzyme activity remain unchanged. These data indicate that, although this
hepatocyte IEG is transcriptionally regulated, the physiologically important
level of regulation is posttranscriptional. This highlights the importance of
correlating gene expression of IEG with protein expression and physiological
function.
PMID- 9756503
TI - Cystatin A expression reduces bile salt-induced apoptosis in a rat hepatoma cell
line.
AB - We have previously demonstrated abrogation of bile salt-induced apoptosis by
cathepsin B inhibitors. However, caspases have been strongly implicated in
apoptosis, and the mechanistic interface between caspase and cathepsin B
activation is unclear. Thus our aims were to determine the mechanistic
relationship between caspases and cathepsin B in bile salt-induced apoptosis in a
rat hepatoma cell line. Expression of cystatin A was used to inhibit cathepsin B,
whereas Z-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK) was used to inhibit
caspases. Cystatin A expression prevented cathepsin B activation and apoptosis
during treatment with glycochenodeoxycholate (GCDC), a toxic bile salt. Caspase N
acetyl-Asp-Glu-Val-Asp-7-amino-4-methylcoumarin (DEVD-AMC) hydrolytic activity
increased in both wild-type and cystatin A-transfected cells treated with GCDC,
demonstrating caspase activation despite inhibition of cathepsin B. In contrast,
Z-VAD-FMK blocked both DEVD-AMC hydrolytic activity and cathepsin B activity
during GCDC treatment. Our data demonstrate that 1) bile salt-induced apoptosis
can be inhibited by the cystatin A transgene and 2) caspase and cathepsin B
activation are linked mechanistically with cathepsin B downstream of caspases.
PMID- 9756504
TI - Effect of VIP and PACAP on basal release of serotonin from isolated vascularly
and luminally perfused rat duodenum.
AB - The effect of vasoactive intestinal polypeptide (VIP), pituitary adenylate
cyclase-activating peptide-38 (PACAP-38), and PACAP-27 on the release of
serotonin (5-HT) into the intestinal lumen and the portal circulation was studied
by using in vivo isolated vascularly and luminally perfused rat duodenum. 5-HT
levels were determined by HPLC. VIP, PACAP-38, and PACAP-27 reduced the luminal
release of 5-HT but did not affect the vascular release of 5-HT. The inhibitory
effect caused by VIP, PACAP-38, and PACAP-27 was not affected by either atropine,
hexamethonium, TTX, or TTX plus ACh, but it was completely antagonized by the
nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine (L-NNA). The VIP
receptor antagonist VIP-(10-28) blocked the effects of VIP, PACAP-38, and PACAP
27. These results suggest that VIP and PACAP exert a direct inhibitory effect on
the luminal release of 5-HT from the enterochromaffin (EC) cells via a common
receptor site on the EC cells and that this effect is mediated by NO but not by
cholinergic pathways. A single injection of TTX, atropine, or hexamethonium
reduced the luminal release of 5-HT, whereas a single injection of VIP-(10-28)
stimulated the luminal release of 5-HT and this effect was antagonized by
atropine, hexamethonium, or TTX. These results suggest that EC cells may receive
the direct innervation of cholinergic neurons as well as VIP and/or PACAP
neurons, with the former exerting a tonic stimulatory influence and the latter
exerting a tonic inhibitory influence on 5-HT release into the intestinal lumen.
PMID- 9756505
TI - Regulation of c-Jun NH2-terminal kinases in isolated canine gastric parietal
cells.
AB - c-Jun NH2-terminal kinases (JNKs) are protein kinases that are activated by a
wide variety of extracellular signals. This study investigated the expression and
regulation of JNKs in isolated gastric canine parietal cells. Western blot
analysis of cell lysates from highly purified (>95%) parietal cells with an
antibody recognizing JNK1 and to a lesser degree JNK2 revealed the presence of
two bands of 46 and 54 kDa, respectively. JNK1 activity was quantitated by
immunoprecipitation and in-gel kinase assays. Of the different agents tested,
carbachol was the most potent inducer of JNK1 activity, whereas histamine and
epidermal growth factor induced weaker responses. The proinflammatory cytokine
tumor necrosis factor-alpha stimulated JNK1 but had no effect on extracellular
signal-regulated kinase (ERK2) induction, suggesting that activation of JNK1
might represent an important event in mediation of the inflammatory response in
the stomach. The action of carbachol was dose (0.1-100 microM) and time
dependent, with a maximal stimulatory effect (fourfold) detected after 30 min of
incubation and sustained for 2 h. Addition of the specific protein kinase C (PKC)
inhibitor GF109203X did not affect the stimulatory action of carbachol. The
intracellular Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic
acid-AM inhibited carbachol induction of JNK1 activity by 60%. Thapsigargin (1
microM), an intracellular Ca2+-rising agent, induced JNK1 activity more than
threefold. Carbachol activation of JNK1 resulted in induction of c-Jun (protein)
transcriptional activity and in stimulation of parietal cell mRNA content of c
jun. In conclusion, our data indicate that carbachol induces JNK activity in
gastric parietal cells via intracellular Ca2+-dependent, PKC-independent
pathways, leading to induction of c-jun gene expression via phosphorylation and
transcriptional activation of c-Jun.
PMID- 9756506
TI - Glutathione depletion is associated with decreased Bcl-2 expression and increased
apoptosis in cholangiocytes.
AB - Cholangiocytes are the target of a group of liver diseases termed the
cholangiopathies that include conditions characterized by periductal inflammation
and cholangiocyte apoptosis. Because inflammation is associated with oxidative
stress, we developed the hypothesis that cholangiocytes exposed to oxidative
stress will be depleted of endogenous cytoprotective molecules, leading to
cholangiocyte apoptosis. To begin to test this hypothesis, we explored the
relationships among glutathione (GSH) depletion, expression of Bcl-2 (a
protooncogene that inhibits apoptosis), and apoptosis in a nonmalignant human
cholangiocyte cell line. Monolayers of human bile duct epithelial cells, derived
from normal liver and immortalized by SV40 transformation, were depleted of GSH
using buthionine sulfoximine (BSO). Bcl-2 expression was assessed by quantitative
immunoblot analysis, and apoptosis quantified by fluorescence microscopy using
the DNA binding dye 4', 6'-diamidino-2-phenylindole. Bcl-2 message was assessed
by RNase protection assay, and Bcl-2 protein synthesis and half-life by pulse
chase analysis. Exposure of human cholangiocytes in culture to BSO reduced GSH
levels by 93 +/- 3% (P < 0.01). In addition, treatment of cholangiocytes with BSO
reduced Bcl-2 levels by 87 +/- 2% (P < 0.01) and was associated with a time
dependent increase in the number of cells undergoing apoptosis; approximately 11
+/- 1% of cultured cells demonstrated morphological changes of apoptosis by 72 h
compared with 1.5 +/- 0.1% in untreated cholangiocytes (P < 0. 01). Maintenance
of GSH levels by addition of glutathione ethyl ester in the presence of BSO
blocked the BSO-associated increase in apoptosis in BSO-treated cholangiocytes
and also prevented the decrease in Bcl-2 protein. BSO treatment of cholangiocytes
did not change steady-state levels of bcl-2 mRNA or Bcl-2 protein synthesis.
However, Bcl-2 protein half-life decreased 57% in BSO-treated vs. untreated
cells. Our results using a human cholangiocyte cell line demonstrate that
reduction in the cellular levels of an antioxidant such as GSH results in
increased degradation of Bcl-2 protein and an increase in apoptosis. These data
provide a mechanistic link between the consequences of oxidative stress and
cholangiocyte apoptosis, an observation that may be important in the pathogenesis
of the inflammatory cholangiopathies.
PMID- 9756507
TI - Effects of sustained flow reduction on postnatal intestinal circulation.
AB - Studies were conducted to determine the effect of mechanically induced sustained
flow reduction on intestinal hemodynamics and oxygenation in 3- and 35-day-old
swine. In vitro gut loops were perfused under controlled-pressure conditions from
an oxygenated blood reservoir at age-appropriate perfusion pressures; pressure
was rapidly reduced to a level that lowered flow rate to approximately 50% of its
baseline value, and pressure was then kept at that level for 2 h. In 3-day-old
intestine, vascular resistance (Ri) increased by 20% immediately after pressure
and flow reduction but then stabilized for 3-4 min; thereafter, flow began to
decrease despite maintenance of perfusion pressure, so that Ri increased an
additional 15% by 30 min after flow reduction. Flow continued to diminish over
the next 90 min, though at much slower rate. Intestine from 35-day-old swine
demonstrated an immediate increase in Ri after pressure and flow reduction, but
thereafter Ri increased very little. The protocol was repeated within in vitro
gut loops perfused under controlled-flow conditions, and within autoperfused,
innervated gut loops developed in vivo and similar observations were made in both
preparations. In 3-day-old intestine, pretreatment with the L-arginine analog
Nomega-monomethyl-L-arginine (10(-4) M) had no effect on the immediate rise in
resistance occurring in the first 1 min but substantially attenuated the
subsequent slow, progressive rise noted thereafter. Pretreatment with the
angiotensin 1A receptor antagonist losartan (2 x 10(-6) M) had no effect on
hemodynamic changes during the first 60 min after mechanical perfusion pressure
reduction but attenuated the very slight increase in resistance noted during the
final 60 min of the protocol. The postnatal intestinal circulation demonstrates
progressive vasoconstriction when its flow rate is mechanically reduced in a
sustained manner, and this effect is age specific, occurring in 3- but not 35-day
old swine. These changes in gut vascular resistance may be consequent to loss of
nitric oxide production and/or local production of angiotensin.
PMID- 9756508
TI - Involvement of pituitary adenylate cyclase-activating peptide in opossum internal
anal sphincter relaxation.
AB - Despite its widespread distribution and significance in the gut, the role of
pituitary adenylate cyclase-activating peptide (PACAP) in internal anal sphincter
(IAS) relaxation has not been examined. This study examined the role of PACAP in
nonadrenergic noncholinergic (NANC) nerve-mediated relaxation of IAS smooth
muscle. Circular smooth muscle strips from the opossum IAS were prepared for
measurement of isometric tension. The influence of PACAP and vasoactive
intestinal peptide (VIP) antagonists and tachyphylaxis on the neurally mediated
IAS relaxation was examined either separately or in combination. The release of
these neuropeptides in response to NANC nerve stimulation before and after the
nitric oxide (NO) synthase inhibitor Nomega-nitro-L-arginine and NO was also
investigated. Both PACAP and VIP antagonists caused significant attenuation of
IAS relaxation by NANC nerve stimulation. The combination of the antagonists,
however, did not have an additive effect on IAS relaxation. VIP tachyphylaxis
caused significant suppression of IAS relaxation by NANC nerve stimulation. PACAP
and VIP were found to be released by NANC nerve stimulation and exogenous NO. The
data suggest the involvement of PACAP in IAS relaxation primarily by the
activation of PACAP1/VIP receptor and lack of its independent role in the
relaxation. Furthermore, NO may regulate the presynaptic release of PACAP and
VIP.
PMID- 9756509
TI - Characterization of the 5'-flanking region of the murine polymeric IgA receptor
gene.
AB - The regulatory elements that control basal and activated transcriptional
expression of the polymeric IgA receptor gene (pIgR) have not been defined. In
this study, we performed functional analysis of the murine pIgR 5'-upstream
region. Transient transfection studies identified the gene's minimal promoter to
reside within 110 nucleotides upstream from the start of transcription.
Substitution mutations of this region identified both a putative activator (-78
to -70) and a repressor (-66 to -52) element. DNase I footprint analysis
confirmed an area of protection that spans from nucleotides -85 to -62. Mobility
shift assays of the putative region confirmed binding of upstream stimulatory
factor 1 (USF1) to an E box element at positions -75 and -70, representing the
putative enhancer. Overexpression studies using various forms of USF suggest that
both USF1 and USF2 enhance activity of the pIgR minimal promoter. We report the
identification and characterization of the murine pIgR minimal promoter, as well
as the critical role of USF in enhancing its basal level of transcription in Caco
2 cells.
PMID- 9756510
TI - Reduced folate derivatives are endogenous substrates for cMOAT in rats.
AB - We examined the role of the canalicular multispecific organic anion transporter
(cMOAT) in the biliary excretion of reduced folate derivatives in vivo and in
vitro using normal [Sprague-Dawley rats (SDR)] and mutant [Eisai
hyperbilirubinemic rats (EHBR)] rats whose cMOAT is hereditarily deficient. In
vivo, the biliary excretion of endogenous tetrahydrofolate (H4PteGlu), 5
methyltetrahydrofolate (5-CH3-H4PteGlu), and 5,10-methylenetetrahydrofolate (5,
10-CH2-H4PteGlu) in EHBR was reduced to 8.2%, 1.9%, and 5.5% of those in SDR,
respectively, whereas that of 10-formyltetrahydrofolate (10-HCO-H4PteGlu) was
detected only in SDR and not in EHBR. Bile drainage caused reduction of
endogenous plasma folate concentrations in SDR but not in EHBR. In vitro,
significant ATP-dependent uptake of 3H-labeled 5-CH3-H4PteGlu into canalicular
membrane vesicles was observed only in SDR. This ATP-dependent uptake was
saturable with a Michaelis constant (Km) value of 126 microM, which was
comparable with its inhibitor constant (Ki) value of 121 microM for the ATP
dependent uptake of a typical cMOAT substrate, 2,4-dinitrophenyl-S-glutathione
(DNP-SG). Vice versa, DNP-SG inhibited the uptake of 5-CH3-H4PteGlu with a Ki of
35 microM, which was similar to its Km value. In addition, H4PteGlu and 5, 10-CH2
H4PteGlu also inhibited the ATP-dependent uptake of DNP-SG. These results
indicate that 5-CH3-H4PteGlu and other derivatives are transported via cMOAT.
Therefore, reduced folate derivatives are the first endogenous substrates for
cMOAT that do not contain glutathione, glucuronide, or sulfate moieties.
PMID- 9756511
TI - Physiological changes in blood glucose affect appetite and pyloric motility
during intraduodenal lipid infusion.
AB - We evaluated the effects of varying blood glucose concentration within the normal
postprandial range and its interaction with small intestinal nutrients on
antropyloric motility and appetite. Eight healthy males (19-40 yr) underwent
paired studies, with a blood glucose level of 5 or 8 mmol/l. Manometry and visual
analog scales were used to assess motility and appetite, during fasting and
intraduodenal lipid infusion (1.5 kcal/min). In the fasting state, antral waves
were suppressed at 8 mmol/l compared with 5 mmol/l (P = 0.018). However, pyloric
motility was no different between the two blood glucose concentrations. Hunger
was no different at 5 mmol/l compared with 8 mmol/l, but fullness was greater at
8 mmol/l (P = 0. 01). During intraduodenal lipid infusion, antral waves were
suppressed (P < 0.035) and isolated pyloric pressure waves (IPPWs) were
stimulated (P < 0.02) compared with during the fasting state, with no difference
between blood glucose concentrations, although the temporal patterning of IPPWs
varied between blood glucose concentrations. The amplitude of IPPWs was greater
at 5 mmol/l compared with 8 mmol/l (P < 0.001), and hunger decreased at 8 mmol/l
compared with 5 mmol/l (P = 0.02). We conclude that "physiological" hyperglycemia
modifies gastric motor and sensory function and that synergy exists between blood
glucose concentration and small intestinal nutrients in modulating gastric
motility and appetite.
PMID- 9756512
TI - Distension-related responses in circular and longitudinal muscle of the human
esophagus: an ultrasonographic study.
AB - Both circular muscles (CM) and longitudinal muscles (LM) of the esophagus
participate in peristalsis. Various measurement techniques have yielded
conflicting information as to the temporal correlation between contraction in the
two muscle layers. High-frequency intraluminal ultrasound (HFIUS) is a novel
technique to detect contraction of LM and CM of the esophagus. We investigated
the temporal correlation between the CM and LM contraction during ascending
excitatory and descending inhibitory reflexes using HFIUS. A manometric catheter
equipped with two balloons and a 12.5-MHz ultrasound transducer catheter was used
to study 10 normal healthy subjects. The changes in muscle thickness and
pressure, proximal and distal to esophageal distension, were recorded at 5 and 10
cm above the lower esophageal sphincter (LES). The esophageal distension induced
an increase in pressure and an increase in muscle thickness of both CM and LM
layers proximal to the distension site. The onset of increase in muscle thickness
and peak muscle thickness in two layers occurred at the same time. There was a
close temporal correlation between the changes in pressure and changes in muscle
thickness. Atropine inhibited the distension-related pressure and muscle
thickness increase in both layers. Distal to the esophageal distension, there was
no change in pressure but a decrease in the thickness of the two muscle layers.
The decrease in muscle thickness of the two layers occurred at the same time. The
responses of the two muscle layers to distension were similar at 5- and 10-cm
sites above the LES. HFIUS is a relatively noninvasive technique to study the LM
layer response during peristalsis in vivo. Our data indicate that the two muscle
layers may contract and relax together during distension-related peristaltic
reflexes in the esophagus.
PMID- 9756513
TI - Anaphylaxis-induced alterations in intestinal motility: role of extrinsic neural
pathways.
AB - The roles of mast cells and extrinsic and vagal neural pathways in the
anaphylaxis-induced alterations in motility observed at sites remote from antigen
exposure were explored. Rats were sensitized to egg albumin (EA) and prepared
with 1) electrodes to monitor intestinal myoelectric activity, 2) an isolated
intestinal loop, and 3) either intact vagal innervation or a subdiaphragmatic
vagotomy. Fasting myoelectric activity was recorded before and after challenge of
the jejunum in continuity or the isolated loop with EA or BSA. Intestinal
segments and the brain stems were processed for mast cell identification
(intestine) or Fos immunoreactivity (brain stem). EA but not BSA challenge of the
jejunum or the isolated loop induced altered motility at both sites and diarrhea.
Granulated mast cells were significantly reduced at the site local to but not
remote from challenge. Vagotomy did not inhibit antigen-induced alterations in
motility or diarrhea. The number of Fos-immunoreactive nuclei in vagal sensory or
motor nuclei was not significantly altered by vagotomy. Thus antigen challenge of
sensitized animals causes mast cell degranulation only at the site of direct
challenge but alters motility at sites local and remote from challenge. The
remote response requires intact extrinsic but not necessarily vagal neural
pathways.
PMID- 9756514
TI - Neural mediation of vasoactive intestinal polypeptide inhibitory effect on
jejunal alanine absorption.
AB - It was recently shown that vasoactive intestinal polypeptide (VIP) inhibits rat
jejunal alanine absorption, an effect that was significantly reduced by vagotomy.
This study assesses the role of capsaicin-sensitive primary afferents (CSPA) and
the myenteric plexus in the inhibition of rat jejunal alanine absorption by VIP.
Continuous intravenous infusion of VIP (11.2 ng . kg-1 . min-1) reduced alanine
absorption by 60% in sham control rats and by 20% in rats neonatally treated with
capsaicin (P < 0.01). In in vitro experiments, VIP decreased alanine uptake by
jejunal strips isolated from sham control rats in a dose-dependent manner. In the
presence of 40 nM VIP, alanine uptake by full-thickness jejunal strips was
reduced by 54% in sham control rats and by 25% in rats neonatally treated with
capsaicin (P < 0.001). On the other hand, VIP reduced alanine uptake by mucosal
scrapings by 25% in sham rats compared with 9% reduction in neonatally treated
rats. Chemical ablation of the extrinsic innervation and jejunal myenteric
plexuses by pretreatment with benzalkonium chloride significantly (P < 0.001)
reduced basal alanine absorption and the inhibitory effect of VIP. Moreover,
incubation of intestinal strips with tetrodotoxin and atropine reduced
significantly (P < 0.05) the inhibitory effect of VIP on alanine absorption.
These data suggest that VIP exerts its inhibitory effect on alanine absorption
through the CSPA fibers and the myenteric plexus. The neuronal circuitry of this
inhibitory process may involve cholinergic muscarinic mechanisms.
PMID- 9756515
TI - 5-HT activates nitric oxide-generating neurons to stimulate chloride secretion in
guinea pig distal colon.
AB - The participation of nitric oxide (NO) in serotonin (5-hydroxytryptamine; 5-HT)
evoked chloride secretion in guinea pig distal colon was examined.
Submucosal/mucosal segments were mounted in Ussing flux chambers, and an increase
in short-circuit current (Isc) was used as an index of secretion. Addition of 5
HT to the serosal side produced a concentration-dependent (10(-7)-10(-5) M)
increase in Isc caused by chloride secretion. NG-nitro-L-arginine (L-NNA)
significantly reduced the 5-HT-evoked early (P-1) and late (P-2) responses to
61.1 and 70.6% of control, respectively. Neurally evoked response was also
inhibited by L-NNA. The NO donor sodium nitroprusside (SNP, 10(-4) M) increased
basal Isc mainly because of chloride secretion. The SNP-evoked response was
significantly reduced by tetrodotoxin but was unchanged by atropine or
indomethacin. These results suggest that the 5-HT-evoked increase in Isc is
associated with an NO-generating mechanism. Atropine significantly reduced the 5
HT (10(-5) M)-evoked P-1 and P-2 responses to 71.8 and 19.7% of control,
respectively. Simultaneous application of atropine and L-NNA further decreased
the 5-HT-evoked responses more than either drug alone; application of L-NNA and
atropine decreased the 5-HT-evoked P-1 and P-2 responses to 68.5 and 39.2% of
atropine-treated tissues, respectively. These results suggest that noncholinergic
components of P-1 and P-2 responses are 71.8 and 19.7% of control, respectively,
and that NO components of P-1 and P-2 responses are 32 and 61%, respectively, of
the noncholinergic component of the 5-HT-evoked responses. The results provide
evidence that NO may participate as a noncholinergic mediator of 5-HT-evoked
chloride secretion in guinea pig distal colon.
PMID- 9756516
TI - Endothelin-1 inhibits secretin-stimulated ductal secretion by interacting with
ETA receptors on large cholangiocytes.
AB - We studied the expression of endothelin-1 (ET-1) receptors (ETA and ETB) and the
effects of ET-1 on cholangiocyte secretion. The effects of ET-1 on cholangiocyte
secretion were assessed in normal and bile duct-ligated (BDL) rats by measuring
1) basal and secretin-induced choleresis in vivo, 2) secretin receptor gene
expression and cAMP levels in small and large cholangiocytes, and 3) luminal
expansion in response to secretin in intrahepatic bile duct units (IBDU). ETA and
ETB receptors were expressed by small and large cholangiocytes. ET-1 had no
effect on basal bile flow or bicarbonate secretion in normal or BDL rats but
decreased secretin-induced bicarbonate-rich choleresis in BDL rats. ET-1
decreased secretin receptor gene expression and secretin-stimulated cAMP
synthesis in large cholangiocytes and secretin-induced luminal expansion in IBDU
from normal or BDL rats. The inhibitory effects of ET-1 on secretin-induced cAMP
synthesis and luminal duct expansion were blocked by specific inhibitors of the
ETA (BQ-610) receptor. ET-1 inhibits secretin-induced ductal secretion by
decreasing secretin receptor and cAMP synthesis, two important determinants of
ductal secretion.
PMID- 9756517
TI - Rat hepatic stellate cells produce cytokine-induced neutrophil chemoattractant in
culture and in vivo.
AB - Hepatic stellate cells are widely recognized for their contribution to liver
fibrosis. This study investigated whether these cells also promote hepatic
inflammation by producing neutrophil chemoattractants. Specifically, stellate
cells were examined as potential sources of cytokine-induced neutrophil
chemoattractant (CINC), a rat chemokine resembling human interleukin-8. Stellate
cells from normal rat liver expressed little or no CINC. In culture, CINC mRNA
was induced rapidly, coinciding with the phenomenon of culture activation. CINC
mRNA rose 4.6-fold within 3 days and was accompanied by secretion of
immunoreactive and biologically active CINC protein (4.1 ng . microgram DNA-1 .
day-1). Studies in vivo demonstrated that CINC could be induced in stellate cells
during liver injury. CINC mRNA rose significantly (4- to 6-fold) in two models of
liver disease, both of which cause stellate cell activation. In summary, the data
indicate that CINC is induced during stellate cell activation in culture and in
vivo. They suggest that stellate cell-derived CINC can promote hepatic
inflammation in vivo.
PMID- 9756518
TI - Localization and secretion of tissue kallikrein in peptidoglycan-induced
enterocolitis in Lewis rats.
AB - The plasma kallikrein-kinin system is a mediator of intestinal inflammation
induced by peptidoglycan-polysaccharide from group A streptococci (PG-APS) in
rats. In this study we investigated the participation of intestinal tissue
kallikrein (ITK). Lewis rats were injected intramurally with PG-APS. ITK was
visualized by immunohistochemical staining. Cecal ITK concentration was measured
by radioimmunoassay, and gene expression was evaluated by RNase protection assay.
Kallikrein-binding protein (KBP) was evaluated in plasma by ELISA. Tissue
kallikrein was identified in cecal goblet cells in both control and PG-APS
injected rats and in macrophages forming granulomas in inflamed tissues. Cecal
ITK was significantly lower in acute and chronic phases of inflammation and in
supernatant from in vitro cultures of inflamed cecum. ITK mRNA levels were not
significantly different. Plasma KBP levels were significantly reduced in inflamed
rats. The presence of tissue kallikrein in macrophages suggests participation in
experimental colitis. The decrease of ITK in the inflamed intestine associated
with unchanged mRNA levels suggests ITK release during intestinal inflammation.
PMID- 9756519
TI - A choline-rich diet improves survival in a rat model of endotoxin shock.
AB - This study investigated whether dietary choline can prevent endotoxin shock.
Female Sprague-Dawley rats fed chow or chow plus choline chloride (0.025-0.4%)
for 3 days were given lipopolysaccharide (LPS) via the tail vein. Eighty-three
percent and 56% of chow-fed rats survived after 2.5 or 5.0 mg/kg LPS,
respectively. Choline increased survival in a dose-dependent manner, with maximal
effects observed at 0.4%; this dose of choline prevented mortality completely
after 2.5 or 5 mg/kg LPS. Choline also improved the microscopic appearance of the
lungs and blunted increases in serum aspartate aminotransferase levels.
Intracellular Ca2+ was monitored in liver and lung macrophages during LPS
exposure. Ca2+ increases in macrophages from choline-fed rats were blunted by 40
60% compared with chow-fed controls. Feeding choline also blunted tumor necrosis
factor-alpha production. Feeding glycine, which prevents macrophage activation
via a chloride channel, in addition to choline was even more effective than
feeding choline alone, suggesting that glycine and choline act via distinct
sites. These data are consistent with the hypothesis that choline diminishes
endotoxin shock by preventing macrophage activation.
PMID- 9756520
TI - Role of nitric oxide in systemic vasopressin-induced hypothermia.
AB - It has been reported that arginine vasopressin (AVP) plays a thermoregulatory
action, but very little is known about the mechanisms involved. In the present
study, we tested the hypothesis that nitric oxide (NO) plays a role in systemic
AVP-induced hypothermia. Rectal temperature was measured before and after AVP,
AVP blocker, or NG-nitro-L-arginine methyl ester (L-NAME; NO synthase inhibitor)
injection. Control animals received saline injections of the same volume. The
basal body temperature (Tb) measured in control animals was 36.53 +/- 0.08
degreesC. We observed a significant (P < 0.05) reduction in Tb to 35.44 +/- 0.19
degreesC after intravenous injection of AVP (2 micrograms/kg) and to 35.74 +/- 0.
10 degreesC after intravenous injection of L-NAME (30 mg/kg). The systemic
injection of the AVP blocker [beta-mercapto-beta, beta
cyclopentamethylenepropionyl1,O-Et-Tyr2,Val4,Arg8]vasopressin (10 micrograms/kg)
caused a significant increase in Tb to 37.33 +/- 0.23 degreesC, indicating that
AVP plays a tonic role by reducing Tb. When the treatments with AVP and L-NAME
were combined, systemically injected L-NAME blunted AVP-induced hypothermia. To
assess the role of central thermoregulatory mechanisms, a smaller dose of L-NAME
(1 mg/kg) was injected into the third cerebral ventricle. Intracerebroventricular
injection of L-NAME caused an increase in Tb, but when intracerebroventricular L
NAME was combined with systemic AVP injection (2 micrograms/kg), no change in Tb
was observed. The data indicate that central NO plays a major role mediating
systemic AVP-induced hypothermia.
PMID- 9756521
TI - Effects of aortic nerve stimulation on discharges of sympathetic neurons
innervating rat tail artery and vein.
AB - Activity was recorded from postganglionic sympathetic neurons (PSNs) innervating
either the caudal ventral artery (CVA) or a lateral vein (LV) of the tail
circulation of anesthetized rats. The study sought to determine whether
sympathetic activity directed at the CVA and LV was influenced by cardiovascular
mechanoreceptor afferents and whether this effect was differential. Cardiac
rhythmicity was not a robust component of either CVA PSN activity or LV PSN
activity. Stimulation of an aortic nerve with short trains was followed by a
decreased probability of discharge in both CVA and LV PSNs that was followed by a
series of peaks that showed a constant periodicity that was not significantly
different from that revealed by autocorrelogram analysis over the same data set.
The latter dominant periodicity is referred to in this and related previous
publications as the T rhythm. Furthermore, blood volume expansion and long-train
aortic nerve stimulation produced a significant decrease in the frequency of the
T rhythm. It is concluded that the CVA and LV sympathetic activity can be
influenced by inputs from cardiovascular mechanoreceptors and that this effect is
mediated in part by a modulation of the T rhythm.
PMID- 9756522
TI - Efficacy of exogenous recombinant murine leptin in lean and obese 10- to 12-mo
old female CD-1 mice.
AB - Leptin efficacy was compared in obese and lean female CD-1 mice. Body weights in
these 10- to 12-mo-old mice ranged from 29.7 to 62.0 g, and leptin levels
correlated with body weight. Mice from the lean and obese ends of the weight
distribution were treated with daily peripheral leptin injections (1-100 mg/kg)
for a 33-day period. The half-maximal effective doses for weight loss and fat
reduction were shifted 0.5-0.7 log to the right for obese mice. Leptin was less
efficacious at low doses (1-3 mg/kg) in obese mice but equal to or more
efficacious in obese than lean mice at high doses (30-100 mg/kg). Leptin's
initial effects on weight loss could be explained by appetite suppression in both
groups, but its effects on fat reduction were greater in leptin-treated than pair
fed mice, particularly in the lean group. Leptin also prevented the elevations in
serum corticosterone and ketones found in pair-fed lean mice. These data allow a
quantitative comparison of leptin sensitivity in obese vs. lean CD-1 mice and
suggest that in mice where obesity is a function of outbreeding and age, leptin
sensitivity is moderately reduced. Furthermore, although appetite suppression has
a clear role in leptin's effects on body weight, leptin may also have specific
effects on lipid metabolism and mobilization that are different from the
metabolic compensations that normally occur with food deprivation.
PMID- 9756523
TI - Stability of circadian timing with age in Syrian hamsters.
AB - The causes of age-related disruptions in the timing of human sleep and
wakefulness are not known but may include changes in both the homeostatic and
circadian regulation of sleep. In Syrian hamsters the free running period of the
circadian activity/rest rhythm has been reported to shorten with age. Although
this has been observed under a variety of experimental conditions, the changes
have been small and their consistency uncertain. In the present study, the wheel
running activity/rest rhythm was continuously measured in male Syrian hamsters
(Mesocricetus auratus) in dim constant light (<1 lx) from 8 wk of age until
death. Fifteen hamsters survived to at least 90 wk (28%). The average free
running period of these hamsters did not change with age. In 18 hamsters that
died between 50 and 88 wk, free running period also did not change before death.
In contrast to free running period, other measures related to activity level
changed significantly with age and before death. Despite changes in the
expression of the activity/rest rhythm, the free running period of the hamster
circadian pacemaker remained remarkably stable with age.
PMID- 9756524
TI - Nutrients regulate diamine oxidase release from intestinal mucosa.
AB - Diamine oxidase is continuously released from the intestinal mucosa and carried
to the circulation by the lymphatics. The effect of nutrients on this release was
examined. Rats were prepared with duodenal and intestinal lymph cannulas. Test
mixtures of lipid emulsions containing triolein, oleic acid, or tricaprylin and
solutions of carbohydrate and protein were infused into the duodenum. The enzyme
release and triglyceride transport were determined and in some experiments were
done in the presence and absence of Pluronic L-81, an inhibitor of chylomicron
formation, and aminoguanidine, an inhibitor of diamine oxidase activity. The data
indicate that nonlipid nutrients did not increase diamine oxidase activity in the
intestinal lymph, but the mucosal tissue content was significantly reduced in the
distal small intestine, particularly after protein infusion. Triglycerides and
fatty acids increased diamine oxidase in the intestinal lymph, and the longer
chain triglyceride was more effective. Inhibition of triglyceride transport did
not interfere with the enzyme release, and the inhibition of diamine oxidase
activity had no significant effect on lipid absorption. According to our
observations, only lipids increase intestinal lymph diamine oxidase. Nonfat
nutrients appear to increase diamine oxidase in the intestinal lumen. Diamine
oxidase is not directly required for lipid absorption.
PMID- 9756525
TI - Leptin does not fully account for the satiety activity of adipose tissue
conditioned medium.
AB - To determine whether leptin alone accounts for the satiety activity secreted by
native adipose tissue, we prepared culture media conditioned by microdissected
adipose tissue from overfed Long-Evans rats, fa/fa rats, or db/db mice (media A,
B, and C, respectively). Medium A significantly suppressed food intake following
intracerebroventricular delivery to Long-Evans rats (2-h chow intake = 68 +/- 5%
of baseline, P < 0.001). Media B and C significantly suppressed food intake
following intraperitoneal delivery to ob/ob mice (24-h chow intake = 56 +/- 7% of
baseline for medium B, P = 0. 001; 4-day chow intake = 78 +/- 3% of baseline for
medium C, P = 0. 004). Using a leptin receptor-based bioassay, we determined that
the leptin concentration of medium C was 392 +/- 18 ng/ml. This concentration was
20-fold lower than the concentration of recombinant murine leptin required to
produce a similar degree of feeding suppression following 5 days of
administration to ob/ob mice. Neither medium conditioned by adipose tissue from
ob/ob mice nor medium conditioned by adipose tissue from fa/fa rats and
subsequently immunodepleted of leptin had significant satiety activity. We
conclude that leptin is necessary but not sufficient to account for the satiety
activity of native adipose tissue, perhaps due to the production by adipocytes of
a cofactor that augments the ability of leptin to suppress feeding.
PMID- 9756526
TI - Effects of costimulation of dopamine D1- and D2-like receptors on renal function.
AB - In vitro studies have suggested that dopamine D1- and D2-like receptors interact
to inhibit renal sodium transport. We used Z-1046, a dopamine receptor agonist
with the rank-order potency D3 >/= D4 > D2 > D5 > D1, to test the hypothesis that
D1- and D2-like receptors interact to inhibit renal sodium transport in vivo in
anesthetized rats. Increasing doses of Z-1046, administered via the right renal
artery, increased renal blood flow (RBF), urine flow, and absolute and fractional
sodium excretion without affecting glomerular filtration rate. For determination
of the dopamine receptor involved in the renal functional effects of Z-1046,
another group of rats received Z-1046 at 2 microgram . kg-1 . min-1 (n = 10) in
the presence or absence of the D2-like receptor antagonist domperidone and/or the
D1-like antagonist SCH-23390. Domperidone alone had no effect but blocked the Z
1046-mediated increase in urine flow and sodium excretion; it enhanced the
increase in RBF after Z-1046. SCH-23390 by itself decreased urine flow and sodium
excretion without affecting RBF and blocked the diuretic, natriuretic, and renal
vasodilatory effect of Z-1046. We conclude that the renal vasodilatory effect of
Z-1046 is D1-like receptor dependent, whereas the diuretic and natriuretic
effects are both D1- and D2-like receptor dependent.
PMID- 9756527
TI - Differential arterial baroreflex regulation of renal, lumbar, and adrenal
sympathetic nerve activity in the rat.
AB - Lumbar (LSNA), renal (RSNA), or adrenal sympathetic nerve activity (ASNA) is most
commonly used as an index of sympathetic nerve activity in investigations of
arterial baroreflex control in the rat. Although differential regulation of
sympathetic outputs to different organs has been extensively studied, no direct
and simultaneous comparisons of the full range of baroreflex reactivity have been
described for these sympathetic outputs. Therefore, we compared steady-state
sigmoidal baroreflex stimulus-response curves (via phenylephrine-nitroprusside
infusion) for RSNA recorded simultaneously with LSNA or ASNA in urethan
chloralose-anesthetized male Sprague-Dawley rats. Characteristics of the
baroreflex curves differed significantly between all three sympathetic outputs.
ASNA exhibited the greatest range of baroreflex regulation, the highest upper
level of activity, and the widest distribution of the gain over a broad range of
mean arterial pressure (MAP). RSNA exhibited greater gain than LSNA. LSNA showed
the smallest range and maximal inhibition in comparison to other sympathetic
outputs. However, all three nerves responded similarly to baroreflex stimulation
and unloading in the range in MAP close to the operating point. We conclude that
baroreflex regulation of sympathetic activity shows wide regional variability in
gain, range, and maximal inhibition. Therefore, the entire stimulus-response
relationship should be considered in comparing regional sympathetic responses.
PMID- 9756528
TI - Acidic fibroblast growth factor activates adrenomedullary secretion and
sympathetic outflow in rats.
AB - Effects of exogenous acidic fibroblast growth factor (aFGF), which is increased
in the brain by food intake, on the plasma levels of catecholamines and on
sympathetic efferent outflow were examined in anesthetized rats. A guide cannula
was inserted into the cerebral third ventricle, and a vascular indwelling
catheter was inserted into the right atrium from the jugular vein. Plasma
epinephrine (Epi) and norepinephrine (NE) increased markedly in a dose-dependent
manner for up to 120 min after intracerebroventricular or intravenous
administration of aFGF (6-667 fmol/rat). Concomitant increases occurred in the
efferent activity in the sympathetic nerves supplying the adrenal, spleen, and
interscapular brown adipose tissue after the above administrations of aFGF. Both
intravenous and intracerebroventricular administration of 10 ng basic FGF (bFGF)
also increased sympathetic adrenal efferent activity and plasma Epi and NE
concentrations. However, the increases induced by 10 ng bFGF were smaller than
those induced by 10 ng aFGF. Bilateral splanchnicotomy completely prevented the
increases in Epi induced by intracerebroventricular or intravenous aFGF but had
less effect on the increases in NE. Pretreatment with an antibody against
corticotropin-releasing factor (CRF), given via the intracerebroventricular
route, significantly attenuated the increases in Epi and NE evoked by
intracerebroventricular or intravenous administration of aFGF. Hepatic vagotomy
also greatly reduced the increases in both catecholamines and the increases in
sympathetic efferent firing rates evoked by intravenous administration of aFGF.
These findings indicate that 1) aFGF administered intracerebroventricularly
activates adrenomedullary secretion and sympathetic outflow via CRF release and
2) aFGF injected intravenously also induces sympathoadrenomedullary activation
via centrally released CRF. The idea is discussed that sympathetic activation
induced either by endogenous aFGF after feeding or by exogenously administered
aFGF may play roles both in energy expenditure after overeating and in the
modulation of immune functions.
PMID- 9756529
TI - Differential suppression of upper airway motor activity during carbachol-induced,
REM sleep-like atonia.
AB - Microinjections of carbachol into the pontine tegmentum of decerebrate cats have
been used to study the mechanisms underlying the suppression of postural and
respiratory motoneuronal activity during the resulting rapid eye movement (REM)
sleep-like atonia. During REM sleep, distinct respiratory muscles are
differentially affected; e.g., the activity of the diaphragm shows little
suppression, whereas the activity of some upper airway muscles is quite strong.
To determine the pattern of the carbachol-induced changes in the activity of
different groups of upper airway motoneurons, we simultaneously recorded the
efferent activity of the recurrent laryngeal nerve (RL), pharyngeal branch of the
vagus nerve (Phar), and genioglossal branch of the hypoglossal (XII) and phrenic
(Phr) nerves in 12 decerebrate, paralyzed, vagotomized, and artificially
ventilated cats. Pontine carbachol caused a stereotyped suppression of the
spontaneous activity that was significantly larger in Phar expiratory (to 8.3% of
control) and XII inspiratory motoneurons (to 15%) than in Phr inspiratory (to
87%), RL inspiratory (to 79%), or RL expiratory motoneurons (to 72%). The
suppression in upper airway motor output was significantly greater than the
depression caused by a level of hypocapnia that reduced Phr activity as much as
carbachol. We conclude that pontine carbachol evokes a stereotyped pattern of
suppression of upper airway motor activity. Because carbachol evokes a state
having many neurophysiological characteristics similar to those of REM sleep, it
is likely that pontine cholinoceptive neurons have similar effects on the
activity of upper airway motoneurons during both states.
PMID- 9756530
TI - Role of endothelial carbon monoxide in attenuated vasoreactivity following
chronic hypoxia.
AB - Chronic hypoxic exposure has been previously demonstrated to attenuate systemic
vasoconstrictor activity to a variety of agents. This attenuated responsiveness
is observed not only in conscious animals but in isolated vascular preparations
as well. Because hypoxia has been documented to increase heme oxygenase (HO)
levels and the subsequent production of the vasodilator CO in vitro, we
hypothesized that the blunted reactivity observed with chronic hypoxia (CH) may
be in part due to increased HO activity. In thoracic aortic rings from CH rats,
cumulative dose-response curves to phenylephrine (PE) in the presence of the
nitric oxide (NO) synthase inhibitor Nomega-nitro-L-arginine (L-NNA) and the HO
inhibitor zinc protoporphyrin 9 (ZnPPIX) elicited increased contractility
compared with CH rings treated with only L-NNA. Similar results were observed in
rings incubated overnight with the HO-inducing agent sodium m-arsenite. In
contrast, contractile responses in rings from control rats were unaffected by the
HO inhibitor. Furthermore, endothelium-denuded rings from either control or CH
rats did not exhibit an increase in reactivity to PE following ZnPPIX incubation.
ZnPPIX had no effect on relaxant responses to the NO donor S-nitroso-N
penicillamine, suggesting that its actions were specific to HO inhibition.
Finally, aortic rings exhibited dose-dependent relaxant responses to exogenous CO
that were endothelium independent and blocked by an inhibitor of soluble guanylyl
cyclase. The other products of HO enzyme activity, iron and biliverdin, were
without effect on vasoreactivity. Thus we conclude that the attenuated
vasoreactivity to PE following CH is likely to involve the induction of
endothelial HO and the subsequent enhanced production of CO.
PMID- 9756532
TI - Continuity between wound macrophage and fibroblast phenotype: analysis of wound
fibroblast phagocytosis.
AB - Analysis of phagocytic activity in wound fibroblasts was chosen as a means to
assess the possible continuity between macrophage and fibroblast phenotypes.
Fibroblast phagocytosis of uncoated, IgG-coated, or collagen-coated fluorescent
beads was analyzed by flow cytometry in vivo and in vitro. Phagocytosis of
fluorescent beads by procollagen I-positive cells (fibroblasts) was evaluated in
vivo by injecting beads into subcutaneously implanted sponge wounds in
anesthetized Fisher rats. Phagocytic activity of a purified population of wound
fibroblasts was measured in vitro and correlated with oxidation state using
hydroethidium. In the wound environment, 50-60% of the cells that engulfed
uncoated, IgG-coated, or collagen-coated beads were procollagen I-positive cells
(i.e., fibroblasts). Procollagen I-positive cells engulfed uncoated and IgG
coated beads in preference to collagen-coated beads in vivo. Cultured wound
fibroblasts engulfed uncoated, IgG-coated, and collagen-coated particles. The
majority of fibroblasts that engulfed beads were in an elevated oxidation state.
We conclude that substantial fibroblast phagocytosis occurs in the wound, but
scavenger receptor-mediated fibroblast phagocytosis is different from that of
macrophages. Additional markers will be helpful in defining the macrophage
fibroblast continuum.
PMID- 9756533
TI - Mechanism of suppressed neutrophil mobilization in a mouse model for binge
drinking: role of glucocorticoids.
AB - The goals of this study were to determine if suppression of neutrophil
accumulation and TNF-alpha production in the peritoneal cavity occurs in mice
exposed to a chemical stressor [ethanol (EtOH)], to evaluate the role of EtOH
induced increases in endogenous glucocorticoids in any such suppression, and to
determine if decreased tumor necrosis factor-alpha (TNF-alpha) production is
responsible for decreases in neutrophil accumulation in EtOH-treated mice. An
inflammatory response induced in the peritoneal cavity of mice by administration
of heat-killed Propionibacterium acnes (P. acnes) was suppressed by a single dose
of EtOH given 1 h before administration of the bacteria, as indicated by
decreased accumulation of neutrophils in the peritoneal cavity. The concentration
of TNF-alpha in the peritoneal cavity was also decreased by EtOH, but exogenous
TNF-alpha did not prevent the suppression of neutrophil accumulation. The
glucocorticoid antagonist RU-486 did not prevent the suppression of neutrophil
accumulation in mice treated with EtOH, but RU-486 did block suppression of
neutrophil accumulation caused by administration of exogenous corticosterone. The
suppression of neutrophil accumulation caused by exogenous corticosterone was
less than produced by EtOH. These observations suggest that the increase in
endogenous corticosterone induced by EtOH may explain some of the suppression of
neutrophil accumulation, but other neuroendocrine mediators (or EtOH per se) are
sufficient to cause the full suppressive effect when the action of corticosterone
is blocked by RU-486. The results also demonstrate that EtOH decreases TNF-alpha
production, but this is not the mechanism by which neutrophil accumulation is
decreased in this model.
PMID- 9756531
TI - Inhibitors of alternative pathways of arachidonate metabolism differentially
affect fever in mice.
AB - Inhibitors of cyclooxygenases prevent fever. The purpose of this study was to
test the hypothesis that selective and dual inhibitors of the other enzyme
systems of arachidonic acid oxygenation (i.e., lipoxygenase and epoxygenase)
affect the time course or magnitude of fever in mice. Swiss Webster mice kept at
30 degreesC ambient temperature were implanted with biotelemeters to monitor body
temperature. Fever was induced by intraperitoneal injection of lipopolysaccharide
at doses from 10 micrograms/kg to 2.5 mg/kg. Phenidone (20-30 mg/kg ip), a dual
lipoxygenase and cyclooxygenase inhibitor, prevented fever in these mice, but
esculetin (1-10 mg/kg ip), a selective inhibitor of lipoxygenases, did not affect
fever. Intramuscular injection of nordihydroguaiaretic acid (10-20 mg/kg), a dual
lipoxygenase and epoxygenase inhibitor, as well as SKF-525A (5 mg/kg ip) and
clotrimazole (20 mg/kg im), inhibitors of the cytochrome P-450/epoxygenase
pathway, augmented fever in mice. Indomethacin (5 mg/kg ip), an inhibitor of
cyclooxygenase, suppressed the exacerbation of fever due to clotrimazole,
suggesting that the epoxygenase inhibitor-induced potentiation of fever in mice
is a prostaglandin-mediated effect. From this study, we hypothesize that the
cytochrome P-450/epoxygenase branch of the arachidonate cascade is involved in
antipyresis and in controlling the upper limit of fever.
PMID- 9756534
TI - Alteration of renal function of rats following spaceflight.
AB - Following spaceflight, changes in renal function of humans have been suggested.
To assess the effects of readaptation on renal function, urine was collected from
male rats ( approximately 245 g) over a 2-wk period following a 14-day
spaceflight. Rats were assigned to three groups: flight animals (n = 6), flight
controls (n = 6) housed in the flight cages on the ground, and vivarium controls
(n = 5) housed in standard shoe box cages. Animals were placed into individual
metabolic cages for urine collection. Urine output was significantly increased
for 3 days following flight. Excretion rates of Na+ and K+ were increased,
resulting in an increased osmotic excretion rate. Creatinine excretion rate
increased over the first two postflight days. Glomerular filtration rate
increased immediately following spaceflight without changes in plasma creatinine,
Na+, K+, or osmolality. Increased excretion of solute was thus the result of
increased delivery and a decreased percent reabsorption of the filtered load.
Osmolal clearance was increased immediately postflight while free water clearance
was decreased. In growing rats, the diuresis after short-duration spaceflight is
the result of an increase in solute excretion with an accompanying reduction in
free water clearance.
PMID- 9756535
TI - Role and mechanism of endothelin-B receptors in mediating ET-1-induced
vasoconstriction in pig skin.
AB - We investigated the functional importance and signal transduction pathways of
endothelin (ET)-B receptors in mediating ET-1-induced vasoconstriction in pig
skin. Skin vasoconstriction was studied by monitoring the perfusion pressure of
isolated perfused pig skin flaps (6 x 16 cm) at a constant flow rate. Intra
arterial infusion of the ETA/B receptor agonist ET-1, the ETB receptor agonists
sarafotoxin 6C (S6c) and BQ-3020, or the thromboxane A2 mimetic U-46619 (n = 4 or
5) caused a concentration-dependent skin vasoconstriction. The vasoconstrictor
potency of ET-1 (EC50 3.1 x 10(-9) M) was lower (P < 0.05) than that of S6c (EC50
1.8 x 10(-9) M) and similar to that of BQ-3020 (EC50 2.6 x 10(-9) M). The
vasoconstrictor potency of ET-1, S6c, and BQ-3020 was at least 300-fold higher
than that of U-46619 (EC50 0.9 x 10(-6) M). The skin vasoconstrictor effect of ET
1 (10(-9)-10(-8) M) was partially inhibited by 10(-5) M BQ-123, an ETA receptor
antagonist. Further inhibition was achieved with the combination of 10(-5) M BQ
123 and BQ-788 (an ETB receptor antagonist) or with an ETA/B receptor antagonist
(10(-5) M bosentan or PD-145065) (n = 5; P < 0.05). In addition, the skin
vasoconstrictor effect of the ETB receptor agonist BQ-3020 was completely blocked
by 5 x 10(-6) M BQ-788 and partially inhibited by 5 x 10(-6) M of the
phospholipase C (PLC) inhibitor 2-nitro-4-carboxyl-N,N-diphenylcarbamate (NCDC),
an L-type Ca2+ channel antagonist (nifedipine), a protein kinase C (PKC)
inhibitor (chelerythrine), or removal of Ca2+ from the perfusate (n = 4 or 5; P <
0.05). The vasoconstrictor effect of S6c was also partially blocked by 5 x 10(-6)
M of NCDC, nifedipine, or chelerythrine or by removal of Ca2+ from the perfusate
(n = 4; P < 0. 01). We conclude that ETB receptors play a central role in
mediating ET-1-induced vasoconstriction in pig skin, and the mechanism probably
involves L-type Ca2+ channels, PLC, and PKC.
PMID- 9756537
TI - Hemodynamic and hormonal responses to hemorrhage in conscious rabbits at mid- and
late gestation.
AB - This study tests the hypothesis that conscious rabbits late in pregnancy (P), but
not at midgestation (MP), are less able to maintain arterial pressure during
hemorrhage. Blood volume (BV) was elevated (P < 0.05) by an average of 13 +/- 4
(MP) and 35 +/- 3% (P). Rabbits were bled in both the nonpregnant (NP) and P
state at 2% of the initial BV per minute. The hemorrhage was stopped after
arterial pressure decreased. In NP rabbits, arterial pressure was well maintained
near control pressures of 70 +/- 2 mmHg until 38 +/- 2% of the initial BV was
removed and then rapidly fell to reach a nadir at 35 +/- 2 mmHg. In contrast, in
P rabbits, basal arterial pressure was lower (61 +/- 2 mmHg; P < 0.05) and
gradually decreased to below control after <25% of the initial BV was removed.
Moreover, the rapid hypotensive phase was triggered with a lower percent BV
removal (33 +/- 2%; P < 0.05). Basal heart rate was higher during P (149 +/- 5
vs. 189 +/- 9 beats/min; P < 0.05), and reflex increases were delayed. The slope
of the relationship between arterial pressure and vasopressin was not modified
during P, although the line was shifted to a lower pressure (P < 0.05). Larger
increases in plasma renin activity and ANG II concentration were produced during
hemorrhage in P rabbits. In contrast, no differences in the changes in arterial
pressure, heart rate, and vasopressin were found between NP and MP rabbits during
hemorrhage, although increases in renin and ANG II were greater at MP (P < 0.05).
In summary, although P conscious rabbits are less able to maintain blood pressure
during hemorrhage, this change is not evident at MP. These data suggest that the
factors that mediate the P-induced alterations in arterial pressure regulation
are not operative until late in gestation.
PMID- 9756536
TI - Role of nitric oxide in adrenal catecholamine secretion in anesthetized dogs.
AB - We examined the role of nitric oxide (NO) in adrenal catecholamine secretion in
response to splanchnic nerve stimulation (SNS) and exogenous acetylcholine (ACh)
in anesthetized dogs. The NO synthase inhibitor Nomega-nitro-L-arginine methyl
ester (L-NAME), NO donor 3-(2-hydroxy-1-methyl-2-nitrosohydrazino)-N-methyl-1
propanamin e (NOC 7), and ACh were administered intra-arterially into the adrenal
gland. The increases in catecholamine output induced by ACh (0.75-3 microgram)
were enhanced by L-NAME (0.1-1 mg/min) and inhibited by NOC 7 (0.2-2
microgram/min). Inhibition by NOC 7 (2 microgram/min) was observed during
treatment with L-NAME (1 mg/min). The increases in catecholamine output induced
by SNS (1-2 Hz) were inhibited by L-NAME and by NOC 7. No inhibitory effect of
NOC 7 was observed during treatment with L-NAME. These results suggest that NO
may play an inhibitory role in the regulation of adrenal catecholamine secretion
in response to exogenous ACh.
PMID- 9756538
TI - Treatment of burned rats with insulin-like growth factor I inhibits the catabolic
response in skeletal muscle.
AB - Thermal injury is associated with a pronounced catabolic response in skeletal
muscle, reflecting inhibited protein synthesis and increased protein breakdown,
in particular myofibrillar protein breakdown. Administration of insulin-like
growth factor I (IGF-I) has a nitrogen-sparing effect after burn injury, but the
influence of this treatment on protein turnover rates in skeletal muscle is not
known. In the present study, we examined the effect of IGF-I on muscle protein
synthesis and breakdown rates following burn injury in rats. After a 30% total
body surface area burn injury or sham procedure, rats were treated with a
continuous infusion of IGF-I (3. 5 or 7 mg . kg-1 . 24 h-1) for 24 h. Protein
synthesis and breakdown rates were determined in incubated extensor digitorum
longus muscles. Burn injury resulted in increased total and myofibrillar protein
breakdown rates and reduced protein synthesis in muscle. The increase in protein
breakdown rates was blocked by both doses of IGF-I and the burn-induced
inhibition of muscle protein synthesis was partially reversed by the higher dose
of the hormone. IGF-I did not influence muscle protein turnover rates in
nonburned rats. The results suggest that the catabolic response to burn injury in
skeletal muscle can be inhibited by IGF-I.
PMID- 9756539
TI - Endothelins inhibit the mineralization of osteoblastic MC3T3-E1 cells through the
A-type endothelin receptor.
AB - We examined the effects of various endothelins on the mineralization of mouse
clonal preosteoblastic MC3T3-E1 cells. MC3T3-E1 cells expressed mRNAs for
endothelin (ET)-1 and the A-type receptor for ET (ETA). A pharmacological study
also demonstrated the predominant expression of the ETA receptor. Northern
blotting analysis revealed that ETs decreased the expression of mRNA for
osteocalcin, which is a marker protein for the maturation of osteoblastic cells.
ET-1 also decreased in the deposition of calcium by MC3T3-E1 cells in a dose
dependent manner and it had an inhibitory effect even at 10(-11) M. The rank
order of potency of ETs was ET-1 = ET-2 > ET-3. Brief treatment with 10(-7) M ET
1 on days 6-8 alone suppressed mineralization. ET-1 enhanced the rate of
production of inositol 1,4, 5-trisphosphate (IP3) in MC3T3-E1 cells, but it had
no effect on the rate of production of cAMP. Taken together, our data indicate
that ET-1 might inhibit the mineralization of osteoblastic cells via an
interaction with the ETA receptor, with generation of IP3 as the intracellular
signal.
PMID- 9756540
TI - Ontogeny of hyperphagia in the Zucker (fa/fa) rat.
AB - The ontogeny of hyperphagic behavior in the Zucker fatty (fa/fa) rat was
examined. Wild-type, +/fa, and fa/fa pups aged postnatal day 5 (P5), P9, P12,
P15, and P18 were evaluated using a test that measured ingestive behavior
independent of the dam. The independent ingestive test consisted of giving pups
access to a test solution [half-and-half (cream and milk)] on a tissue on the
floor of a test chamber for 20 min. The latency to ingest and the intake (weight
gain and percent weight gain) were measured and normalized to +/fa littermates.
Pups were tested once to eliminate any effects of test experience. fa/fa Pups
ingested significantly more than lean pups (+/+ and +/fa) on P12, P15, and P18,
but not on P5 or P9. The latencies of fa/fa pups did not differ significantly
from the latencies of +/+ pups except on P18, when the latencies of fa/fa pups
were significantly shorter. The latencies of +/fa pups were significantly longer
than the latencies of fa/fa or +/+ pups on P5 and P12. These results demonstrate
that hyperphagia in fa/fa rats emerges between P9 and P12 under the test
conditions used.
PMID- 9756541
TI - Dissimilarity of slow-wave activity enhancement by torpor and sleep deprivation
in a hibernator.
AB - Sleep regulation processes have been hypothesized to be involved in function and
timing of arousal episodes in hibernating ground squirrels. We investigated the
importance of sleep regulation during arousal episodes by sleep deprivation
experiments. After sleep deprivation of 4, 12, and 24 h, starting 4 h after onset
of euthermy, a duration-dependent enhancement of slow-wave activity (SWA) of the
cortical electroencephalogram during non-rapid eye movement sleep was found, as
expected for normal sleep regulation. When sleep deprivation was applied during
the initial phase of the arousal episode, in which effects of prior torpor were
present in undisturbed recordings, no subsequent recurrence of SWA was found. In
addition, prior torpor induced a reduction in the spectral activity of the sigma
frequency range (7-14 Hz), which was not observed after sleep deprivation. The
effects of torpor and sleep deprivation on subsequent SWA appear qualitatively
different. This indicates that effects of deep torpor on sleep are dissimilar to
normal sleep regulation.
PMID- 9756542
TI - Contrasting cardiovascular effects following central and peripheral injections of
trout galanin in trout.
AB - Little is known about the role of galanin (Gal) in fish. In the present study,
cardiovascular effects of central and peripheral administrations of a synthetic
replicate of trout Gal (tGal) were investigated in the unanesthetized trout.
Intracerebroventricular injection of 0.1, 0.5, 1.0, and 3.0 nmol/kg body mass of
the peptide demonstrated that the two highest doses tested produced a significant
(P < 0.001) and equivalent increase in mean dorsal aortic blood pressure (PDA)
without changing heart rate (HR). At a dose of 1.0 nmol/kg, the systemic vascular
resistance (Rs) increased, but no change was detected in cardiac output compared
with that produced by intracerebroventricular injection of vehicle only. In
contrast, intra-arterial injections of 0.1, 0.5, and 1.0 nmol/kg body mass of
tGal produced a dose-dependent decrease in PDA with a threshold dose for
significant effects observed at a dose of 0.5 nmol/kg. None of the doses tested
changed HR. At a dose of 1 nmol/kg, a significant decrease in Rs (P < 0.001) was
the factor responsible for the fall in PDA. Intra-arterial injection of porcine
Gal (1 nmol/kg) produced a change in PDA similar to that of the same dose of
tGal, but HR increased slightly. Pretreatments of trout with the cyclooxygenase
inhibitors indomethacin and meclofenamate did not inhibit the vasodepressor
effects of tGal. However, after intra-arterial injection of NG-nitro-L-arginine
methyl ester, an inhibitor of nitric oxide synthase, the hypotensive action of
Gal was reduced threefold, suggesting the possible involvement of the nitric
oxide system in mediating the vasodilatory effect of Gal. In conclusion, our
results have shown that tGal may have contrasting cardiovascular regulatory
functions in trout depending on whether its site of action is the brain or the
peripheral circulation.
PMID- 9756543
TI - Genetic variation in EEG activity during sleep in inbred mice.
AB - The genetic variation in spontaneous rhythmic electroencephalographic (EEG)
activity was assessed by the quantitative analysis of the EEG in six inbred mice
strains. Mean spectral EEG profiles (0-25 Hz) over 24 h were obtained for
paradoxical sleep (PS), slow-wave sleep (SWS), and wakefulness. A highly
significant genotype-specific variation was found for theta peak frequency during
both PS and SWS, which strongly suggests the presence of a gene with a major
effect. The strain distribution of theta peak frequency during exploratory
behavior differed from that during sleep. In SWS, the relative contributions of
delta (1-4 Hz) and sigma (11-15) power to the EEG varied with genotype and power
in both frequency bands was negatively correlated. In addition, the EEG dynamics
at state transitions were analyzed with a 4-s resolution. The onset of PS, but
not that of wakefulness, was preceded by a pronounced peak in high-frequency (>11
Hz) power. These findings are discussed in terms of the neurophysiological
mechanisms underlying rhythm generation and their control and modulation by the
brain stem reticular-activating system.
PMID- 9756544
TI - Altered expression of type 2 CRH receptor mRNA in the VMH by glucocorticoids and
starvation.
AB - In the rat, high-dose corticosterone (Cort) administration, the hypercortisolism
of starvation, and adrenalectomy are all associated with decreased food intake
and weight loss. We report here a study of the effects of high-dose Cort
administration, starvation, and adrenalectomy on two peripheral hormones known to
influence food intake and energy use, insulin and leptin. We also studied the
impact of these interventions on the levels of type 2 corticotropin-releasing
hormone receptor (CRHR-2) mRNA in the hypothalamic paraventricular nucleus (PVN)
and ventromedial hypothalamus (VMH). The VMH is classically referred to as the
satiety center because electrical stimulation of the VMH leads to inhibition of
food intake, whereas CRHR-2 are thought to transduce the profound anorexogenic
effects of CRH or its related peptide urocortin. Starvation and adrenalectomy
each lowered plasma insulin and leptin levels and were associated with decrements
in CRHR-2 mRNA levels in the VMH. Cort administration increased plasma leptin
levels profoundly, as well as plasma insulin levels and the levels of VMH CRHR-2
mRNA. Under all experimental conditions, a positive correlation was seen between
plasma leptin levels and VMH CRHR-2 mRNA. These data suggest that decreased food
intake and weight loss after high-dose Cort administration at least partially
depend on the profound impact of Cort on plasma leptin secretion in the rat; they
suggest, moreover, an additional mechanism for the satiety-inducing effects of
leptin, namely increasing CRHR-2 in the VMH. The concordance of a fall in plasma
insulin and leptin levels with the fall in VMH CRHR-2 mRNA levels further
supports the idea that compensatory responses during starvation and adrenalectomy
include not only the disinhibiting effects of reduced insulin and leptin levels
on appetite through already-described mechanisms but also via an effect of leptin
on VMH CRHR-2. Neither Cort administration, starvation, nor adrenalectomy
influenced the levels of CRHR-2 mRNA in the PVN, suggesting that these receptors
are differentially regulated in different hypothalamic regions.
PMID- 9756545
TI - Cytokines mediate protective stimulation of glucocorticoid output during
autoimmunity: involvement of IL-1.
AB - Endogenous glucocorticoid levels are increased during experimental autoimmune
encephalomyelitis (EAE) in Lewis rats. Although this endocrine response is
essential for survival, the mechanism that triggers the stimulation of
glucocorticoid output during the disease remains unknown. We report here that 1)
after immunization with the encephalitogenic antigen myelin basic protein (MBP),
increased blood glucocorticoid levels are not only observed in Lewis rats, but
also in PVG rats, which do not develop EAE; 2) immune cells obtained from animals
with EAE and stimulated in vitro with MBP produced mediators that increased
glucocorticoid levels when administered to naive recipients; and 3) acute in vivo
blockade of interleukin-1 (IL-1) receptors inhibited, to a large extent, the
increase in corticosterone levels during EAE. These results show that the
increase in corticosterone levels after immunization with MBP can be dissociated
from the stress of the paralytic attack that characterizes EAE. Furthermore, they
indicate that an endocrine response, which is decisive for the prevention or
moderation of EAE, is mainly the result of the stimulation of the hypothalamic
pituitary-adrenal axis by cytokines produced during the immune response that
induces the autoimmune disease.
PMID- 9756546
TI - Intracellular pH regulation in neurons from chemosensitive and nonchemosensitive
areas of the medulla.
AB - Intracellular pH (pHi) regulation was studied in neurons from two chemosensitive
[nucleus of the solitary tract (NTS) and ventrolateral medulla (VLM)] and two
nonchemosensitive [hypoglossal (Hyp) and inferior olive (IO)] areas of the
medulla oblongata. Intrinsic buffering power (betaint) was the same in neurons
from all regions (46 mM/pH U). Na+/H+ exchange mediated recovery from
acidification in all neurons [Ritucci, N. A., J. B. Dean, and R. W. Putnam. Am.
J. Physiol. 273 (Regulatory Integrative Comp. Physiol. 42): R433-R441, 1997]. Cl
/HCO-3 exchange mediated recovery from alkalinization in VLM, Hyp, and IO neurons
but was absent from most NTS neurons. The Na+/H+ exchanger from NTS and VLM
neurons was fully inhibited when extracellular pH (pHo) <7.0, whereas the
exchanger from Hyp and IO neurons was fully inhibited only when pHo <6.7. The Cl
/HCO-3 exchanger from VLM, but not Hyp and IO neurons, was inhibited by pHo of
7.9. These pH regulatory properties resulted in steeper pHi-pHo relationships in
neurons from chemosensitive regions compared with those from nonchemosensitive
regions. These differences are consistent with a role for changes of pHi as the
proximate signal in central chemoreception and changes of pHo in modulating pHi
changes.
PMID- 9756547
TI - Differential catecholamine responses to protein intake in healthy and
hypertensive subjects.
AB - Protein intake-induced natriuresis previously related to increased urinary
dopamine excretion was reexamined in an extensive controlled study comparing
healthy and hypertensive subjects. In healthy subjects, ingestion of 1 g/kg wt
tuna induced natriuresis that was associated, between postprandial hours 1 and 2,
with increased plasma tyrosine [191 +/- 13% (mean +/- SE); P < 0.01], 3, 4
dihydroxyphenylalanine (104 +/- 12%, P < 0.05 in plasma; 162 +/- 20%, P < 0.05 in
urine), plasma free dopamine (156 +/- 32%; P < 0. 05), and dopamine sulfate (191
+/- 11%, P < 0.001 in plasma; 199 +/- 15%, P < 0.01 in urine) but affected
urinary free dopamine excretion only at limits of significance. Hypertensive
subjects had less (P < 0.02) natriuresis and, despite comparable plasma tyrosine
and dopamine sulfate increases, no increase in plasma and urinary 3, 4
dihydroxyphenylalanine and plasma free dopamine. Their plasma and urinary free
epinephrine responses were less (P < 0.05) than the borderline increases in
control subjects. Compared with control subjects, they significantly increased
plasma 3, 4-dihydroxyphenylalanine sulfate (P < 0.05), epinephrine sulfate (P <
0.05), and the dopamine sulfate-to-free dopamine ratio (P < 0.02). Postprotein
natriuresis is thus associated with nutritional priming-induced plasma but not
urinary free dopamine increase. Hypertensive subjects have attenuated natriuretic
and plasma free dopamine responses and less free epinephrine increase. This may
partly result from higher circulating 3,4-dihydroxyphenylalanine, dopamine, and
epinephrine sulfoconjugates leaving fewer free amines for biological actions.
PMID- 9756548
TI - Role of central catecholaminergic pathways in the actions of endogenous ANG II on
sympathetic reflexes.
AB - In the present study, we examined the effect of blockade of the brain stem renin
angiotensin system on renal sympathetic baroreflexes and chemoreflexes in
conscious rabbits and examined the role of central catecholaminergic pathways in
these responses. Eleven rabbits underwent preliminary surgical instrumentation
and pretreatment with central 6-hydroxydopamine (6-OHDA, 500 micrograms/kg) or
ascorbic acid 6 wk before the commencement of the experiments. Baroreflex curves
were determined under conditions of normoxia and hypoxia (10% O2 + 3% CO2) before
and after central administration of either Ringer solution, the ANG II receptor
antagonist losartan (10 micrograms), or the angiotensin-converting enzyme
inhibitor enalaprilat (500 ng) on separate days. Losartan increased the upper
plateau and the range of the mean arterial pressure (MAP)-renal sympathetic nerve
activity (RSNA) curve (79 and 78%, respectively) in intact rabbits, whereas this
effect was not observed in 6-OHDA-pretreated rabbits. Hypoxia elicited an
increase in resting RSNA (111% in intact rabbits and 74% in 6-OHDA-injected
rabbits) and elevated the upper plateau of the RSNA-MAP curve in both groups (89%
in intact rabbits and 114% in 6-OHDA-injected rabbits). During hypoxia, losartan
and enalaprilat increased the RSNA upper plateau in intact rabbits but had no
effect in 6-OHDA-pretreated rabbits. No effects on the MAP-heart rate baroreflex
curves were observed. Thus the effect of losartan to increase RSNA, particularly
during hypoxia and baroreceptor unloading, being abolished by central
noradrenergic depletion suggests that the endogenous ANG II which normally causes
an inhibition of renal sympathetic motoneurons is dependent on the integrity of
central catecholaminergic pathways.
PMID- 9756549
TI - Interleukin-4 inhibits spontaneous sleep in rabbits.
AB - Proinflammatory cytokines, including interleukin-1beta (IL-1beta) and tumor
necrosis factor-alpha, are involved in sleep regulation. IL-4 is an
antiinflammatory cytokine that inhibits proinflammatory cytokine production. The
hypothesis that IL-4 should attenuate sleep was studied by determining the
effects of IL-4 on rabbit spontaneous sleep. Thirty-six rabbits were used. Four
doses of IL-4 (0.25, 2.5, 25, and 250 ng) were injected intracerebroventricularly
during the rest (light) period. One dose of IL-4 (25 ng) was injected during the
active (dark) cycle. Appropriate time-matched control injections of saline were
done in the same rabbits on different days. The three highest doses of IL-4
significantly inhibited spontaneous non-rapid eye movement sleep if IL-4 was
given during the light cycle. The highest dose of IL-4 (250 ng) also
significantly decreased rapid eye movement sleep. On the other hand, IL-4
administered at dark onset had no effect on sleep. The sleep inhibitory
properties of IL-4 provide additional evidence for the hypothesis that a brain
cytokine network is involved in the regulation of physiological sleep.
PMID- 9756550
TI - Poor relationship between arterial [lactate] and leg net release during exercise
at 4,300 m altitude.
AB - We evaluated the hypotheses that on acute exposure to hypobaric hypoxia,
sympathetic stimulation leads to augmented muscle lactate production and
circulating [lactate] through a beta-adrenergic mechanism and that beta
adrenergic adaptation to chronic hypoxia is responsible for the blunted exercise
lactate response after acclimatization to altitude. Five control and 6 beta
blocked men were studied during rest and exercise at sea level (SL), on acute
exposure to 4,300 m (A1), and after a 3-wk sojourn at altitude (A2). Exercise was
by leg cycling at 49% of SL peak O2 consumption (VO2 peak) (65% of altitude VO2
peak or 87 +/- 2.6 W); beta-blockade was by propranolol (80 mg 3x daily), femoral
arterial and venous blood was sampled; leg blood flow (Q) was measured by
thermodilution, leg lactate net release [ = (2) (1-leg Q) venous-arterial
concentrationL] was calculated, and vastus lateralis needle biopsies were
obtained. Muscle [lactate] increased with exercise and acute altitude exposure
but regressed to SL values with acclimatization; beta-blockade had no effect on
muscle [lactate]. Arterial [lactate] rose during exercise at SL (0.9 +/- 0.1 to
1.5 +/- 0.3 mM); exercise at A1 produced the greatest arterial [lactate] (4.4 +/-
0.8 mM), and exercise at A2 an intermediate response (2.1 +/- 0.6 mM). beta
Blockade reduced circulating [lactate] approximately 45% during exercise under
all altitude conditions. increased transiently at exercise onset but then
declined over time under all conditions. Blood and muscle "lactate paradoxes"
occurred independent of beta-adrenergic influences, and the hypotheses relating
the blood lactate response at altitude to beta-adrenergic mechanisms are
rejected. During exercise at altitude, arterial [lactate] is determined by
factors in addition to hypoxemia, circulating epinephrine, and net lactate
release from active muscle beds.
PMID- 9756551
TI - Effects of 17beta-estradiol on sympathetic activity and pressor response to
phenylephrine in ovariectomized rats.
AB - The effects of 17beta-estradiol (E2) on sympathetic activity were examined in
conscious unrestrained ovariectomized rats, instrumented under methohexital
anesthesia to record mean arterial pressure (MABP), heart rate (HR), renal nerve
activity (RNA), and splanchnic nerve activity (SNA) 1 day before the experiment.
Injection of E2 (150 micrograms/kg iv) caused reductions (P < 0.01) in RNA (29 +/
6%), SNA (25 +/- 2%), and HR (26 +/- 5 beats/min) within 20 min, but MABP
remained unchanged. Ninety minutes after intravenous injection of E2 or vehicle,
intravenous infusion of phenylephrine (PE; 6.2 micrograms . min-1 . kg-1) induced
similar increases in MABP and decreases in HR, RNA, and SNA in both groups. By
contrast, in rats chronically treated with E2, the pressor response to PE was
smaller (P < 0.01; 22 +/- 5 mmHg) than in vehicle-treated rats (40 +/- 4 mmHg).
The changes in HR, RNA, and SNA were similar in both groups, but the ratios of
changes in HR and SNA to MABP, an index of baroreflex sensitivity, were greater
in the E2-treated rats. These findings suggest that E2 can act centrally to
modulate sympathetic function and thereby participate in cardiovascular
regulation.
PMID- 9756552
TI - The area postrema does not modulate the long-term salt sensitivity of arterial
pressure.
AB - The hindbrain circumventricular organ, the area postrema (AP), receives multiple
signals linked to body fluid homeostasis. In addition to baroreceptor input, AP
cells contain receptors for ANG II, vasopressin, and atrial natriuretic peptide.
Hence, it has been proposed that the AP is critical in long-term adjustments in
sympathetic outflow in response to changes in dietary NaCl. The present study was
designed to test the hypothesis that long-term control of arterial pressure over
a range of dietary NaCl requires an intact AP. Male Sprague-Dawley rats were
randomly selected for lesion of the AP (APx) or sham lesion. Three months later,
rats were instrumented with radiotelemetry transmitters for continuous monitoring
of mean arterial pressure (MAP) and heart rate and were placed in individual
metabolic cages. Rats were given 1 wk postoperative recovery. The dietary salt
protocol consisted of a 7-day period of 1.0% NaCl (control), 14 days of 4.0% NaCl
(high), 7 days of 1.0% NaCl, and finally 14 days of 0.1% NaCl (low). The results
are reported as the average arterial pressure observed on the last day of the
given dietary salt period: APx (n = 7) 114 +/- 2 (1.0%), 110 +/- 3 (4.0%), 110 +/
3 (1.0%), and 114 +/- 4 (0.1%) mmHg; sham (n = 6) 115 +/- 2 (1.0%), 114 +/- 3
(4.0%), 111 +/- 3 (1. 0%), and 113 +/- 2 (0.1%) mmHg. Neither group of rats
demonstrated significant changes in MAP throughout the entire dietary salt
protocol. Furthermore, no significant differences in MAP were detected between
groups throughout the protocol. All lesions were histologically verified. These
results suggest that the area postrema plays no role in long-term control of
arterial pressure during chronic changes in dietary salt.
PMID- 9756553
TI - Slow restoration of LH pulsatility by refeeding in energetically disrupted women.
AB - In other energy-restricted mammals, a single large meal restores luteinizing
hormone (LH) pulsatility within a few hours. To determine whether this is so in
women, we measured LH pulsatility during the 5th day of low energy availability
[dietary energy intake - exercise energy expenditure = 10 kcal . kg lean body
mass (LBM)-1 . day-1] and during a 6th day of aggressive refeeding (90 kcal . kg
LBM-1 . day-1) in 15 meals providing 4,100 kcal for an energy availability of 75
kcal . kg LBM-1 . day-1. Low energy availability raised beta-hydroxybutyrate
1,000% (P < 0.001) and reduced plasma glucose 15% (P < 0.01), insulin 63% (P <
0.001), and triiodothyronine 22% (P < 0.005). In five of eight subjects, low
energy availability also unambiguously suppressed LH pulse frequency 57% to 8.2
+/- 1.5 pulses/24 h (P < 10(-4)) and raised LH pulse amplitude 94% to 3.1 +/- 0.3
IU/l (P < 10(-4)), levels below the 5th and above the 95th percentile,
respectively, in energy-balanced women. Aggressive refeeding restored beta
hydroxybutyrate, glucose, and insulin, but not triiodothyronine. In the five
women with unambiguously disrupted LH pulsatility, aggressive refeeding had no
effect on LH pulse amplitude (P > 0.9) and raised LH pulse frequency only
slightly (2.4 +/- 0.6 pulses/24 h, P = 0.04) and not above the fifth percentile.
This striking contrast between women and other mammals may be another clue to the
unidentified mechanism mediating the effect of energy availability on LH
pulsatility.
PMID- 9756554
TI - N-acetylcysteine does not affect the lymphocyte proliferation and natural killer
cell activity responses to exercise.
AB - This study evaluated whether N-acetylcysteine (NAC) attenuates the reduced
lymphocyte proliferation and natural killer (NK) cell activity responses to
exercise in humans. Fourteen oarsmen were double-blind randomized to either NAC
(6 g daily for 3 days) or placebo groups. During 6-min "all-out" ergometer
rowing, the concentration of lymphocytes in the peripheral blood increased, with
no significant difference between NAC and placebo as reflected in lymphocyte
subsets: CD4(+), CD8(+), CD16(+), and CD19(+) cells. The phytohemagglutinin
stimulated lymphocyte proliferation decreased from 9,112 +/- 2,865 to 5,851 +/-
1,588 cpm (P < 0.05), but it was not affected by NAC. During exercise, the NK
cell activity was elevated from 17 +/- 3 to 38 +/- 4% and it decreased to 7 +/-
1% below the resting value 2 h into recovery. Yet, when evaluated as lytic units
per CD16(+) cell, the NK cell activity decreased during and after exercise
without a significant effect of NAC. We conclude that NAC does not attenuate the
reduction in lymphocyte proliferation and NK cell activity associated with
intense exercise.
PMID- 9756555
TI - Differential regulation of uncoupling protein gene homologues in multiple tissues
of hibernating ground squirrels.
AB - Nonshivering thermogenesis in brown adipose tissue (BAT) provides heat through
activation of a mitochondrial uncoupling protein (UCP1), which causes futile
electron transport cycles without the production of ATP. Recent discovery of two
molecular homologues, UCP2, expressed in multiple tissues, and UCP3, expressed in
muscle, has resulted in investigation of their roles in thermoregulatory
physiology and energy balance. To determine the expression pattern of Ucp
homologues in hibernating mammals, we compared relative mRNA levels of Ucp1, -2,
and -3 in BAT, white adipose tissue (WAT), and skeletal muscle of arctic ground
squirrels (Spermophilus parryii) hibernating at different ambient and body
temperatures, with levels determined in tissues from ground squirrels not in
hibernation. Here we report significant increases in mRNA levels for Ucp2 in WAT
(1. 6-fold) and Ucp3 in skeletal muscle (3-fold) during hibernation. These
results indicate the potential for a role of UCP2 and UCP3 in thermal homeostasis
during hibernation and indicate that parallel mechanisms and multiple tissues
could be important for nonshivering thermoregulation in mammals.
PMID- 9756556
TI - Renal denervation supersensitivity revisited.
AB - To determine whether the chronically denervated kidney is supersensitive to
either physiological or pathophysiological plasma levels of norepinephrine (NE),
studies were conducted in conscious dogs subjected to unilateral renal
denervation and surgical division of the urinary bladder into hemibladders to
allow separate 24-h urine collection from denervated and innervated kidneys.
Plasma NE concentration was increased by chronic infusion of NE (4-5 days) at
rates of 25, 100, and 200 ng . kg-1 . min-1. Twenty-four-hour control values for
mean arterial pressure (MAP), plasma NE concentration, and ratios for urinary
sodium and potassium excretion from denervated and innervated kidneys (Den/Inn)
were 94 +/- 4 mmHg, 145 +/- 24 pg/ml, 1.05 +/- 0.05, and 0.97 +/- 0.07,
respectively. With infusions of NE producing plasma levels of NE of up to
approximately 3,000 pg/ml or plasma concentrations of NE at least threefold
greater than present under most pathophysiological conditions and during acute
activation of the sympathetic nervous system, there were no significant long-term
changes in MAP or relative excretion rates of sodium and potassium from
denervated and innervated kidneys. In marked contrast, pharmacological plasma
levels of NE ( approximately 7,000 pg/ml) produced chronic increases in MAP (to
116 +/- 2% of control) and sustained reductions in Den/Inn for urinary sodium and
potassium excretion to 57 +/- 4 and 68 +/- 5% of control, respectively,
indicating a lower excretion rate of these electrolytes from denervated vs.
innervated kidneys. We conclude that the chronically denervated kidney does not
exhibit an exaggerated antinatriuretic response to either physiological or
pathophysiological levels of circulating NE. It is therefore unlikely that renal
denervation supersensitivity is a confounding issue in studies employing chronic
renal denervation to elucidate the role of the renal nerves in the regulation of
sodium excretion.
PMID- 9756557
TI - Heterogeneous neurochemical responses to different stressors: a test of Selye's
doctrine of nonspecificity.
AB - Selye defined stress as the nonspecific response of the body to any demand.
Stressors elicit both pituitary-adrenocortical and sympathoadrenomedullary
responses. One can test Selye's concept by comparing magnitudes of responses at
different stress intensities and assuming that the magnitudes vary with stress
intensity, with the prediction that, at different stress intensities, ratios of
increments neuroendocrine responses should be the same. We measured arterial
plasma ACTH, norepinephrine, and epinephrine in conscious rats after hemorrhage,
intravenous insulin, subctaneous formaldehyde solution, cold, or immobilization.
Relative to ACTH increments, cold evoked large norepinephrine responses, insulin
large epinephrine responses, and hemorrhage small norepinephrine and epinephrine
responses, whereas immobilization elicited large increases in levels of all three
compounds. The ACTH response to 25% hemorrhage exceeded five times that to 10%,
and the epinephrine response to 25% hemorrhage was two times that to 10%. The
ACTH response to 4% formaldehyde solution was two times that to 1%, and the
epinephrine response to 4% formaldehyde solution exceeded four times that to 1%.
These results are inconsistent with Selye's doctrine of nonspecificity and the
existence of a unitary "stress syndrome," and they are more consistent with the
concept that each stressor has its own central neurochemical and peripheral
neuroendocrine "signature."
PMID- 9756559
TI - Myostatin expression in porcine tissues: tissue specificity and developmental and
postnatal regulation.
AB - The objective of this study was to establish the developmental pattern and tissue
specificity of porcine myostatin expression and to evaluate expression in
skeletal muscle during circumstances in which muscle growth was altered. Northern
blot analysis revealed two transcripts (1.5 and 0.8 kb). Myostatin mRNA was
detected in whole fetuses at 21 and 35 days and was markedly increased (P < 0.05)
by 49 days. At birth, mRNA abundance in longissimus muscle had declined
significantly (P < 0.05) from that at day 105 of gestation and continued to
decrease (P < 0.05) to its lowest level 2 wk postnatally (4 kg body wt).
Myostatin expression was higher (P < 0. 05) at 55, 107, and 162 kg body wt than
at 4 kg body wt. Postnatally, myostatin mRNA was detected in skeletal muscle and
mammary gland. Expression at birth was 65% higher (P < 0.04) in longissimus
muscle of low-birth-weight piglets (0.57 +/- 0.052 kg body wt) vs. normal (1.37
+/- 0.077 kg body wt) littermates, irrespective of gender. However, suppression
of longissimus muscle growth by food deprivation (3 days) did not alter (P >
0.15) myostatin expression in either 4- or 7-wk-old piglets. Additionally,
myostatin mRNA abundance was not changed by porcine growth hormone administration
in growing animals. These data indicate that myostatin expression in skeletal
muscle peaks prenatally and that greater expression is associated with low birth
weight. Expression in mammary gland indicates a possible role for myostatin in
mammary gland development and/or lactation.
PMID- 9756558
TI - NG-hydroxy-L-arginine and nitric oxide inhibit Caco-2 tumor cell proliferation by
distinct mechanisms.
AB - The objective of this study was to elucidate the role and mechanism of nitric
oxide (NO) synthase (NOS) in modulating the growth of the Caco-2 human colon
carcinoma cell line. The two novel observations reported here are, first, that NG
hydroxy-L-arginine (NOHA) inhibits Caco-2 tumor cell proliferation, likely by
inhibiting arginase activity, and, second, that NO causes cytostasis by
mechanisms that might involve inhibition of ornithine decarboxylase (ODC)
activity. Both arginase and ODC are enzymes involved in the conversion of
arginine to polyamines required for cell proliferation. Cell growth was monitored
by cell count, cell protein analysis, and DNA synthesis. NOHA (1-30 microM) and
NO in the form of DETA/NO (1-30 microM) inhibited cell proliferation by 30-85%.
The cytostatic effect of NOHA was prevented by addition of excess ornithine,
putrescine, spermidine, or spermine to cell cultures, whereas the cytostatic
effect of NO (DETA/NO) and alpha-difluoromethylornithine (ODC inhibitor) was
unaffected by ornithine but was prevented by putrescine, spermidine, or spermine.
The cytostatic effect of NOHA appeared to be independent of its conversion to NO,
and the effect of NO appeared to be independent of cGMP. NOHA inhibited urea
production by Caco-2 cells and inhibited arginase catalytic activity (85% at 3
microM), whereas NO (DEA/NO and SNAP) inhibited ODC activity (>/=60% at 30
microM) without affecting arginase activity. Coculture of Caco-2 cells with
lipopolysaccharide/cytokine-activated rat aortic endothelial cells markedly
slowed Caco-2 cell proliferation, and this was blocked by NOS inhibitors. These
observations that NOHA and NO may inhibit sequential steps in the arginine
polyamine pathway suggest a novel biological role for NOS in the inhibition of
cell proliferation of certain tumor cells and possibly other cell types.
PMID- 9756560
TI - Sympathetic nerve activity during natural stimulation of horizontal semicircular
canals in humans.
AB - We have shown that static head-down neck flexion elicits increases in muscle
(MSNA) but not skin sympathetic nerve activity (SSNA) in humans. These findings
suggest that stimulation of the otolith organs causes differential sympathetic
outflow to vascular beds. The purpose of the present study was to determine
whether yaw head rotation (YHR), which stimulates the horizontal semicircular
canals, elicits sympathetic nerve responses. To test this question, we recorded
MSNA (n = 33) and SSNA (n = 25) before and during 3 min of sinusoidal YHR
performed at 0.1, 0.6, and 1.0 Hz. At all frequencies, YHR elicited no
significant changes in heart rate and mean arterial pressure. Likewise, YHR did
not significantly change either MSNA or SSNA at all frequencies. Our results
indicate that stimulation of the horizontal semicircular canals by YHR does not
alter SNA to either muscle or skin. Moreover, these results provide evidence to
support the concept that the otolith organs but not the horizontal semicircular
canals participate in the regulation of SNA in humans.
PMID- 9756561
TI - Altered regulation of bladder nerve growth factor and neurally mediated
hyperactive voiding.
AB - Elevated bladder smooth muscle cell (BSMC) nerve growth factor (NGF) secretion
and related neuroplasticity are associated with hyperactive voiding in
spontaneously hypertensive rats (SHRs: hypertensive, behaviorally hyperactive),
compared with control Wistar-Kyotos (WKYs). We used two inbred strains (WKHT:
hypertensive; WKHA: hyperactive) to further investigate this phenomenon. WKHA
BSMCs secreted higher basal levels of NGF than WKHT BSMCs. Antagonists did
inhibit NGF output in WKHA but not WKHT cultures. Thus augmented basal secretion
of NGF cosegregates with a hyperactive phenotype, whereas a lack of regulatory
inhibition of NGF output cosegregates with a hypertensive phenotype. Bladder
norepinephrine content paralleled NGF content, with WKHTs > SHRs > WKHAs > WKYs,
providing evidence that a lack of inhibition is the greatest contributor to
elevated bladder NGF and noradrenergic innervation. Protein kinase C (PKC)
agonists affected NGF production differentially depending on strain, suggesting
that altered PKC signaling may contribute to strain differences in NGF secretion.
Finally, 6-h voiding frequency differed between the strains, with SHRs > WKHTs =
WKHAs > WKYs. Thus aspects of both the hypertensive and hyperactive phenotypes
may be associated with elevated SHR bladder NGF and hyperactive voiding.
PMID- 9756562
TI - Uncoupling of the autonomic and cardiovascular systems in acute brain injury.
AB - We hypothesized that acute brain injury results in decreased heart rate (HR)
variability and baroreflex sensitivity indicative of uncoupling of the autonomic
and cardiovascular systems and that the degree of uncoupling should be
proportional to the degree of neurological injury. We used HR and blood pressure
(BP) power spectral analysis to measure neuroautonomic regulation of HR and BP
and the transfer function magnitude (TF) between BP and HR as a measure of
baroreflex modulation of HR. In 24 brain-injured patients [anoxic/ischemic injury
(n = 7), multiple trauma (n = 6), head trauma (n = 5), central nervous system
infection (n = 4), and intracranial hemorrhage (n = 2)], neurological injury and
survival was associated with low-frequency (0.01-0.15 Hz) HR and BP power and TF.
Brain-dead patients showed decreased low-frequency HR power [0. 51 +/- 0.36 (SE)
vs. 2.54 +/- 0.14 beats/min2, P = 0.03] and TF [0. 61 +/- 0.16 (SE) vs. 1.29 +/-
0.07 beats . min-1 . mmHg-1, P = 0.05] compared with non-brain-dead patients. We
conclude that 1) severity of neurological injury and outcome are inversely
associated with HR and BP variability and 2) there is direct evidence for
cardiovascular and autonomic uncoupling in acute brain injury with complete
uncoupling during brain death.
PMID- 9756563
TI - Chemical specificities and intestinal distributions of nutrient-driven satiety.
AB - We measured intakes of sham- and naturally feeding rats during gut perfusions of
nutrients. Our objectives were to determine 1) which nutrient products in gut
lumen suppressed intakes; 2) how suppression by various nutrients is distributed
along gut; and 3) whether time courses of suppression were similar among
different nutrients. We found that satiating nutrients consisted of fatty acids
only longer than 10 carbons, of monomeric carbohydrates only with affinity for
the glucose transporter, and, among several amino acids, of only phenylalanine
and tryptophan. Dimeric maltose had about the same potency as an isocaloric
mixture of longer glucose polymers; since responses to either were blocked by a
glucosidase inhibitor, each probably acted after hydrolysis to free glucose.
Effective nutrients suppressed intakes about equally on infusion into duodenum
vs. midgut, and the same nutrients also suppressed intakes when infused into
colon. Food intakes were suppressed only while maltose was infused, not after it
was stopped, but suppression persisted for 2 h after stopping perfusions with
fatty or amino acids.
PMID- 9756564
TI - Length of intestinal contact on nutrient-driven satiety.
AB - Chemosensors throughout small bowel and colon inhibit food intakes when contacted
by monomeric nutrients. We postulated that calorie-dependent inhibition of food
intakes depended on additions of feedbacks from sensors in proximal and distal
bowel contacted after high intakes of nutrients. Therefore, we determined how
feedback from sensors in proximal gut interacted with feedback from
simultaneously contacted sensors in distal bowel and whether suppression of
nutrient intakes by intestinally perfused nutrients depended on length of gut
contacted. Suppression of food intakes by maltose simply added to that from
dodecanoate when both were present together either in proximal or distal small
bowel. When dodecanoate was infused into proximal gut while maltose was infused
distally, suppression of intake was threefold higher and was thus potentiated.
Limiting contact of slowly absorbed lactose or oleate to 35 cm of jejunum nearly
abolished the satiating potencies each exhibited during access to whole gut. The
observations were consistent with our hypothesis.
PMID- 9756566
TI - Neuronal cell bodies in paraventricular nucleus affect renal hemodynamics and
excretion via the renal nerves.
AB - Several lines of evidence support the existence of an oligosynaptic projection
from the paraventricular nucleus of the hypothalamus (PVN) to the kidney in the
rat. We sought to provide evidence that this neural pathway is capable of
influencing renal function in rats. Bilateral microinjections of bicuculline
(Bic; 1 nmol) into the PVN decreased glomerular filtration rate (59%), effective
renal plasma flow (71%), urine flow (UV; 57%), and urinary sodium excretion
(UNaV; 54%), accompanied by increased mean arterial pressure (17%) and heart rate
(17%). These results were not obtained when Bic was injected outside the PVN or
when vehicle (0.9% saline) was injected into the PVN. Bilateral renal denervation
(5-7 days before the experiments) significantly reduced the renal
vasoconstriction, attenuated the antidiuresis, and abolished the antinatriuresis
evoked by PVN stimulation. On the other hand, both the antidiuresis and
antinatriuresis evoked by PVN stimulation were undiminished after treatment with
either of two vasopressin receptor antagonists ([beta-mercapto-beta,beta
cyclopentamethylenepropionyl1,O-Et-Tyr2, Val4,Arg8]vasopressin, a vasopressin V1
receptor antagonist, or [adamantaneacetyl1,O-Et-D-Tyr2,Val4,aminobutyryl6,Arg8,
9]-vasopressin, a V2 receptor antagonist). In renal-denervated rats treated with
the same V2 receptor antagonist, PVN stimulation produced highly variable
increases in both UV and UNaV, which overall were not statistically different
than zero. We conclude that the activation of neurons in PVN evokes 1) renal
vasoconstriction accompanied by antinatriuresis, both of which are attributable
to the renal nerves, and 2) decreased water excretion, which is mediated by the
renal nerves and vasopressin V2 receptors.
PMID- 9756565
TI - Role of small intestine in caloric compensations to oil premeals in rats.
AB - We postulated that dose-responsive satiety after oil premeals varies with the
number of gut sensors stimulated by lipolytic products along intestine. These
experiments in fasted rats on satiety after oil premeals were performed to 1)
determine whether satiety was induced by lipolytic products but not
triglycerides; 2) confirm that oil empties from the stomach at rates that vary
with oil loads; 3) ascertain that increasing rates of oil entry into duodenum
extend the length of gut contacted by lipolytic products; and 4) judge whether
length of gut contacted correlated with dose-responsive satieties to dietary
oils. 5) Using specific antagonists, we attempted to define how satiety was
signalled by gut sensors. Timing and degrees of satiety did not correlate with
timing and extent of gastric distensions but, rather, with the timing and extent
of spread of lipolytic products along small bowel. Satiety after the highest
premeal load of oil was blocked by Pluronic L-81, an inhibitor of intestinal
secretion of apolipoprotein A-IV, but was unaffected by MK-329 (a specific
antagonist of cholecystokinin) or by capsaicin blockade of chemosensory nerves.
PMID- 9756567
TI - Evidence for increased cardiac compliance during exposure to simulated
microgravity.
AB - We measured hemodynamic responses during 4 days of head-down tilt (HDT) and
during graded lower body negative pressure (LBNP) in invasively instrumented
rhesus monkeys to test the hypotheses that exposure to simulated microgravity
increases cardiac compliance and that decreased stroke volume, cardiac output,
and orthostatic tolerance are associated with reduced left ventricular peak
dP/dt. Six monkeys underwent two 4-day (96 h) experimental conditions separated
by 9 days of ambulatory activities in a crossover counterbalance design: 1)
continuous exposure to 10 degrees HDT and 2) approximately 12-14 h per day of 80
degrees head-up tilt and 10-12 h supine (control condition). Each animal
underwent measurements of central venous pressure (CVP), left ventricular and
aortic pressures, stroke volume, esophageal pressure (EsP), plasma volume, alpha1
and beta1-adrenergic responsiveness, and tolerance to LBNP. HDT induced a
hypovolemic and hypoadrenergic state with reduced LBNP tolerance compared with
the control condition. Decreased LBNP tolerance with HDT was associated with
reduced stroke volume, cardiac output, and peak dP/dt. Compared with the control
condition, a 34% reduction in CVP (P = 0.010) and no change in left ventricular
end-diastolic area during HDT was associated with increased ventricular
compliance (P = 0.0053). Increased cardiac compliance could not be explained by
reduced intrathoracic pressure since EsP was unaltered by HDT. Our data provide
the first direct evidence that increased cardiac compliance was associated with
headward fluid shifts similar to those induced by exposure to spaceflight and
that reduced orthostatic tolerance was associated with lower cardiac
contractility.
PMID- 9756568
TI - Cytokine-induced fever in obese (fa/fa) and lean (Fa/Fa) Zucker rats.
AB - In earlier work, we reported that genetically obese (fa/fa) Zucker rats exhibited
significantly greater anorexia than did lean (Fa/Fa) Zucker rats to
intracerebroventricular infusion of interleukin (IL)-1beta. Here, we investigated
the fever response of obese (fa/fa) and lean (Fa/Fa) Zucker rats to
intracerebroventricular microinfusion of IL-1beta as well as to the following
other cytokines: IL-2, IL-6, and tumor necrosis factor-alpha (TNF-alpha). Core
body temperature was monitored by a radiotelemetry system in freely moving rats.
The results show that 1) both IL-1beta and IL-6 induce fevers in obese and lean
rats; 2) IL-1beta induces a significantly higher fever response in obese rats
than it does in lean rats; 3) IL-6 induces a significantly higher fever response
in lean rats than it does in obese rats; 4) IL-2 induces a moderate fever
response in lean but not obese rats; 5) TNF-alpha induces a similar fever
response in obese and lean rats; and 6) the fevers induced by each effective
cytokine have different time courses. Thus obese (fa/fa) and lean (Fa/Fa) Zucker
rats show differential responsiveness to the intracerebroventricular
microinfusion of various classes of cytokines. This suggests that genetic obesity
in the fa/fa Zucker rat is associated with differential cytokine action on
thermoregulatory mechanisms.
PMID- 9756569
TI - Evidence for induction of a phosphate appetite in juvenile rats.
AB - This study examined whether dietary phosphate (Pi) restriction stimulates an
appetite for Pi in the juvenile rat, which normally has a high metabolic Pi
demand for growth. Juvenile Wistar rats were placed in individual cages with
unrestricted access to tap water and a low (LPD, 0.02% Pi) or normal Pi diet
(NPD, 0.6% Pi) for 7 days. On day 8, both groups of rats were given unlimited
access to a solution of 0.3 M potassium phosphate water (PiH2O) for 8 additional
days. Rats fed LPD consumed 70-100% more PiH2O then those rats fed NPD (P <
0.001). The increase in PiH2O intake resulted in a marked rise in the growth rate
of rats fed LPD during days 8-15. A similar Pi intake was inducible after only 2
days of LPD and was associated with significant reductions in both plasma and
cerebrospinal fluid (CSF) Pi levels; these levels remained low throughout Pi
restriction, despite a significant PiH2O intake. Furthermore, the renal
adaptation to enhance Pi reabsorption (TmPi) during Pi deprivation remained
elevated despite enhanced PiH2O intake. Replenishment with a high-Pi diet rapidly
quenched the PiH2O appetite and was associated with restoration of both plasma
and CSF Pi levels. These findings suggest that an appetite for Pi can be induced
in juvenile rats, perhaps through lowered plasma and CSF Pi levels. This
behavioral response may serve as an additional mechanism to maintain an adequate
supply of Pi necessary for growth and development of the animal.
PMID- 9756571
TI - Gestational obesity accentuates obesity in obesity-prone progeny.
AB - Maternal obesity and genetic background can affect the development of obesity and
diabetes in offspring. Here we used selected strains of rats resistant (DR) vs.
susceptible to development of diet-induced obesity (DIO) on high-energy (HE)
diets to assess this issue. DR and DIO dams were fed either Chow or HE diet for 4
wk. DIO HE diet-fed dams and additional DR rats fed a palatable liquid diet
(Ensure) became more obese and hyperinsulinemic than the other groups. During
lactation, all dams were fed their respective diets, and offspring were fed Chow
from weaning to 16 wk of age. All offspring of DIO dams gained more weight and
had heavier retroperitoneal fat pads and higher leptin levels than DR progeny,
but offspring of the more obese DIO HE dams had heavier fat pads and higher
glucose levels than DIO Chow offspring. After 4 wk on HE diet, all DIO offspring
gained more weight and had heavier total adipose depots and higher insulin and
leptin levels than DR offspring. Offspring of DIO HE dams also gained more weight
and had heavier fat depots and higher leptin levels than DIO Chow offspring.
Therefore maternal obesity and hyperinsulinemia were associated with increased
obesity in those offspring already genetically predisposed to become obese.
PMID- 9756570
TI - Spinal and peripheral mechanisms contributing to hyperactive voiding in
spontaneously hypertensive rats.
AB - The influence of noradrenergic mechanisms involved in micturition in
spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats was
investigated using continuous cystometry in in vivo and in vitro studies on
isolated bladder and urethral tissues. Compared with WKY rats, SHR had a
significantly lower bladder capacity (SHR: 0.7 +/- 0. 05 ml; WKY rats: 1.3 +/-
0.06 ml; P < 0.001), micturition volume (SHR: 0.4 +/- 0.04 ml, WKY rats: 1.2 +/-
0.05 ml; P < 0.001), and an increased amplitude of nonvoiding (unstable) bladder
contractions. The effects of intrathecal and intra-arterial doxazosin on
cystometric parameters were more pronounced in SHR than in WKY rats. There was a
marked reduction in nonvoiding contractions after intrathecal (but not intra
arterial) doxazosin in SHR. Norepinephrine (0.1 microM-1 mM) failed to evoke
contractions in bladder strips from WKY rats, in contrast to a weak contractile
response in SHR. The response to electrical field stimulation was significantly
less in bladder strips from SHR than from WKY rats. In WKY rats, norepinephrine
produced concentration-dependent inhibition (87 +/- 5%, n = 6) of nerve-evoked
bladder contractions. Almost no inhibition (11 +/- 8%, n = 6) was found in SHR.
Alterations in bladder function of SHR appear to be associated with changes in
the noradrenergic control of the micturition reflex, in addition to an increased
smooth muscle and decreased neuronal responsiveness to norepinephrine. The marked
reduction in nonvoiding contractions after intrathecal doxazosin suggests that
the bladder hyperactivity in SHR has at least part of its origin in supraspinal
and/or spinal structures.
PMID- 9756572
TI - Pregnancy-induced changes in rabbit medial collateral ligament vasoregulation.
AB - The ligaments of weight-bearing joints are known to become mechanically inferior
during pregnancy, and it has been postulated that this may be due to changes in
tissue perfusion. Calcitonin gene-related peptide (CGRP) and epinephrine exert a
tonic influence on the vasculature of the medial collateral ligament (MCL), and
the present study examined whether these vasoactive influences were altered by
pregnancy. Ligament perfusion experiments were performed on primigravid New
Zealand White rabbits with the use of laser Doppler perfusion imaging. In
pregnant animals (day 29), MCL basal perfusion fell significantly compared with
control; however, values returned to normal 5 days postpartum. In normal joints,
topical application of CGRP resulted in a dose-dependent increase in MCL
perfusion, whereas epinephrine administration caused a dose-dependent fall in
blood flow. During pregnancy, the vasodilator effect of CGRP was completely
abolished, whereas adrenergic vasoconstriction was greater than normal. Both
responses returned postpartum. Pregnancy in the rabbit produces hypoemia in the
MCL, and this phenomenon may be effected by a tempering of CGRP dilator responses
and an augmentation of alpha-adrenoceptor-mediated vasoconstriction.
PMID- 9756573
TI - AHA journals lead with definitive new online site.
PMID- 9756574
TI - Changing practice and costs of carotid endarterectomy in Toronto, Canada.
AB - BACKGROUND AND PURPOSE: During our annual audits of carotid endarterectomy (CEA)
in Toronto metropolitan hospitals, we have been aware of major changes in the
practice of this operation in recent years. To evaluate the effect of changing
practice on costs of carotid endarterectomy, we have therefore compared the
effects of changes in length of stay, complication rates, and other variables on
cost during the last 3 years for which we have complete data. METHODS: We
evaluated 757 consecutive patients, of whom 600 had CEA procedures in 3 teaching
hospitals, and 190 procedures in 2 community hospitals in metropolitan Toronto.
We estimated costs using a specially designed computer program, Transitional
System Incorporated, including surgical complications, in patients admitted
between January 1994 and December 1996. RESULTS: There was a significant decrease
in length of stay in both groups of hospitals, mainly due to preoperative
outpatient evaluation but also due to lower complication rates, which probably
reflect an increase in asymptomatic surgery in both hospital groups. Costs fell
from approximately $8000 per procedure to $5000 in asymptomatic patients and from
approximately $10,000 to $7000 in symptomatic patients (Can $). CONCLUSIONS:
Major changes in the management of patients undergoing CEA have resulted in a
significant decrease in both length of hospital stay and utilization of
postoperative intensive care. At the same time, complication rates have
significantly fallen, although our mortality and morbidity figures remain
slightly higher than those from published multicenter trials. Future changes in
surgical practice in Canada, including noninvasive carotid imaging, should
produce even lower costs within the next few years.
PMID- 9756575
TI - Recurrent carotid stenosis : results of the asymptomatic carotid atherosclerosis
study.
AB - BACKGROUND AND PURPOSE: We sought to determine the incidence of recurrent carotid
stenosis in patients in the Asymptomatic Carotid Atherosclerosis Study (ACAS) who
had undergone carotid endarterectomy and were prospectively followed with Doppler
ultrasound for up to 5 years. METHODS: The ACAS database was interrogated to
determine the rate of recurrent carotid stenosis (>/=60%) based up angiogram
validated Doppler data, with a 90% and a 95% positive predictive value, as well
as information concerning the technologists' interpretation of percent stenosis.
These 3 parameters are reported for each of 3 time intervals: within 3 months of
operation (residual disease), between 3 and 18 months (early restenoses), and
between 18 and 60 months (late restenosis). RESULTS: Of the 825 patients
randomized to the surgical arm of the study, 720 actually underwent carotid
endarterectomy, and 645 had complete ultrasound data. The aggregate incidence of
residual and recurrent carotid stenosis for all time intervals ranged from 12.7%
to 20.4%, depending on the positive predictive value confidence level desired.
Residual disease occurred in 4.1% to 6.5%; true, early restenosis was found in
7.6% to 11.4%; and late restenosis occurred in 1.9% to 4.9%. None of the
traditional risk factors showed a statistically significant effect on recurrent
stenosis. The use of patch angioplasty closure reduced overall risk of restenosis
from 21.2% to 7.1%, from 16.7% to 4.6%, and from 27.4% to 8.2%, depending on the
PPV confidence level desired (P<0.001). Of the 136 patients judged to have
recurrent stenosis, only 8 (5.9%) underwent reoperation (only 1 for symptoms).
There was no correlation between late stroke and recurrent stenosis. CONCLUSIONS:
Carotid endarterectomy is a durable procedure with a low rate of true restenosis,
particularly when patch angioplasty is used to close the arteriotomy.
PMID- 9756576
TI - Three-dimensional ultrasound study of carotid arteries before and after
endarterectomy; analysis of stenotic lesions and surgical impact on the vessel.
AB - BACKGROUND AND PURPOSE: It has been proved that symptomatic patients with severe
carotid stenosis benefit from endarterectomy. Currently used methods for
quantitation of the severity of carotid stenosis have limitations, and the impact
of endarterectomy on the operated region of carotid artery remains unknown. The
purpose of this study was to examine the accuracy of a 3-D ultrasound system for
quantitation of stenotic lesions and to evaluate changes in regional vessel
volume and cross-sectional area after carotid endarterectomy. METHODS: We studied
14 patients with both carotid angiography and 3-D ultrasound. Of 13 patients who
underwent surgery, 12 were reexamined with 3-D ultrasound after surgery. The
length and volume of 20 randomly selected plaques were measured from 3-D data
sets. The severity of stenosis was quantified by 3-D ultrasound using both a
diameter method and an area method on cross-sectional views at the most stenotic
site; the results were then compared with those from carotid angiography. The
segmental vessel volume and average cross-sectional area of the operated artery
both before and after endarterectomy were measured from 3-D ultrasound data.
RESULTS: Good correlation was obtained between 3-D ultrasound and carotid
angiography in quantitative analysis of carotid stenosis (SEE=12.4%, r=0.76, and
mean difference=7.0+/-12.3% with the diameter method; SEE=10.5%, r=0.82, and mean
difference=1.8+/-10.5% with the area method by 3-D ultrasound). 3-D ultrasound
had excellent reproducibility and small intraobserver and interobserver
variability in plaque length and volume measurements. No significant changes in
segmental vessel volume and average cross-sectional area of the operated artery
were observed after surgery in patients with suture closure. However, a
significant increase in segmental vessel volume was obtained in patients with
polyfluorethylene patches applied to the surgical opening of the artery.
CONCLUSIONS: 3-D ultrasound can be used for both qualitative and quantitative
analysis of plaques in the carotid artery and to detect and quantify significant
carotid stenosis. Its volumetric potential has important clinical implications in
serial follow-up studies for observing the progression or regression of stenotic
lesions and for evaluating the outcome of interventional procedures such as
endarterectomy or stent placement.
PMID- 9756577
TI - Comparison of near-infrared spectroscopy and somatosensory evoked potentials for
the detection of cerebral ischemia during carotid endarterectomy.
AB - BACKGROUND AND PURPOSE: We sought to assess the clinical value of regional
cerebral saturation (rSO2) obtained by means of the cerebral oximeter INVOS 3100A
(Somanetics) in comparison to monitoring of somatosensory evoked potentials (SEP)
for the reliable detection of severe cerebral ischemia requiring shunt placement
in the individual patient undergoing carotid surgery under general anesthesia.
METHODS: In 317 patients undergoing reconstructive surgery on the internal
carotid artery, simultaneous recordings of SEP and rSO2 were obtained throughout
the operation. RESULTS: All 287 patients with preserved cortical SEP remained
neurologically intact. Shunt placement was performed in 27 patients (9%) after
flattening of cortical SEP during cross-clamping of the internal carotid artery.
A stable rSO2 value just before cross-clamping and the lowest value after cross
clamping were registered, and the decrease was calculated. A statistically
significant (P<0.01) decrease of rSO2 after cross-clamping could be found in
patients without (64.9+/-8.3% to 60.9+/-9.9%) as well as in patients with
consecutive loss of cortical SEP (65.8+/-9.1% to 56.1+/-13.4%). The difference of
the decrease of rSO2 in both groups was highly significant (6.9+/-9.0% versus
15.6+/-14.0%; P<0.001). However, substantial interindividual variability of rSO2
and derived change of rSO2 did not allow the definition of a threshold value
indicating need of shunt placement. CONCLUSIONS: The reliability of SEP for the
detection of clamp-related hypoperfusion has been reaffirmed. As long as rSO2
threshold values indicating critical cerebral ischemia are not defined,
therapeutic interventions based on monitoring with the cerebral oximeter INVOS
3100A are not justified.
PMID- 9756578
TI - Predicting the effect of carotid artery occlusion during carotid endarterectomy:
comparing transcranial doppler measurements and cerebral angiography.
AB - BACKGROUND AND PURPOSE: We correlated the mean transcranial Doppler blood flow
velocity (FVm) during carotid endarterectomy with the functional collateral
pathway(s) documented by angiography. METHODS: Three patient groups were
established: group 1 was dependent on the anterior communicating artery, group 2
on the anterior communicating artery and ipsilateral posterior communicating
artery, and group 3 on the ipsilateral posterior communicating artery. Continuous
middle cerebral artery FVm and electroencephalographic monitoring were performed
in 45 patients during carotid endarterectomy. RESULTS: Clamped FVm was lowest in
group 3 at 17+/-9 cm/s versus 36+/-16 and 33+/-11 cm/s for groups 1 and 2
(P<0.01). FVm values in groups 1 and 2 were similar. There was significant
cerebral arterial vasodilation in group 3 patients on the basis of a pulsatility
index of 0.38+/-0.15. The maximum FVm after clamp release was similar among the 3
groups. Normalized blood flow velocity 1 minute before release of the clamp was
increased from the minimum flow velocity after clamping only in group 1 and 2
patients. CONCLUSIONS: The ipsilateral posterior communicating artery is a minor
collateral pathway during acute carotid occlusion that contributes little to the
collateral flow if there is a functional anterior communicating artery.
Collateral flow through the middle cerebral artery is not recruited during
occlusion in group 3 patients. The reperfusion FVm transient is independent of
the primary collateral pathway. Documentation of functional collateral pathways
on the basis of Doppler or angiographic examination may be advantageous in future
studies since it can provide the basis for comparison among studies.
PMID- 9756579
TI - Paraoxonase PON1 polymorphism leu-Met54 is associated with carotid
atherosclerosis: results of the Austrian Stroke Prevention Study.
AB - BACKGROUND AND PURPOSE: Genetic polymorphism at the paraoxonase locus is
associated with serum concentration and activity of paraoxonase and with
increased risk for coronary heart disease. Two frequent polymorphisms present at
the paraoxonase gene are the methionine (M allele) leucine (L allele) interchange
at position 54 and the arginine (B allele) glutamine (A allele) interchange at
position 191. This is the first study to determine the effect of these
polymorphisms on carotid atherosclerosis. METHODS: The paraoxonase genotypes at
positions 54 and 191 of 316 randomly selected individuals aged 44 to 75 years
were determined by polymerase chain reaction-based restriction enzyme digestion.
Carotid atherosclerosis was assessed by color-coded Duplex scanning and was
graded on a 5-point scale ranging from 0 (normal) to 5 (complete luminal
obstruction). RESULTS: The LL, LM, and MM genotypes at position 54 were noted in
137 (43.4%), 132 (41.8%), and 47 (14.9%) subjects; the AA, AB, and BB genotypes
at position 191 occurred in 172 (54.4%), 124 (39.2%), and 20 (6.3%) individuals.
The LL genotype was significantly associated with the presence and severity of
carotid disease (P=0.022), whereas the 191 polymorphism had no effect. Logistic
regression analysis with age and sex forced into the model demonstrated plasma
fibrinogen (odds ratio [OR], 1.005 per mg/dL), LDL cholesterol (OR, 1.01 per
mg/dL), cardiac disease (OR, 1.75), and the paraoxonase LL genotype to be
significant predictors of carotid atherosclerosis. The ORs for the associations
with age and sex were 1.09 (P=0.0003) and 1.66 (P=0.052) per year. CONCLUSIONS:
These data suggest that the paraoxonase LL genotype may represent a genetic risk
factor for carotid atherosclerosis.
PMID- 9756580
TI - Physical activity and stroke incidence: the Harvard Alumni Health Study.
AB - BACKGROUND AND PURPOSE: Physiologically, it appears plausible for physical
activity to decrease stroke risk; however, epidemiological studies have produced
mixed findings. Furthermore, few studies have examined specific kinds and
intensities of activities. The purpose of this study was to examine the
association between physical activity, including its various components (walking,
climbing stairs, participation in sports and recreational activities), and stroke
risk. METHODS: This was a prospective cohort study of 11 130 Harvard University
alumni (mean age, 58 years) without cardiovascular disease and cancer at
baseline. Men reported their walking, stair climbing, and participation in sports
or recreation on baseline questionnaires in 1977. Stroke occurrence was assessed
with another questionnaire in 1988. Death certificates were obtained for
decedents through 1990 to determine strokes not previously reported (total
strokes=378). We used Cox proportional hazards regression to estimate the
relative risks and 95% CIs for stroke occurrence associated with physical
activity. RESULTS: After adjustment for age, smoking, alcohol intake, and early
parental death, the relative risks of stroke associated with <1000, 1000 to 1999,
2000 to 2999, 3000 to 3999, and >/=4000 kcal/wk of energy expenditure at baseline
were 1.00 (referent), 0.76 (95% CI, 0.59 to 0.98), 0.54 (0.38 to 0. 76), 0.78
(0.53 to 1.15), and 0.82 (0.58 to 1.14), respectively; P=0. 05 for linear trend.
Walking >/=20 km/wk was associated with significantly lower risk, independent of
other physical activity components. Climbing stairs and activities of at least
moderate intensity (>/=4.5 METs, or multiples of resting metabolic rate) each
showed U-shaped relations to stroke risk, with the risk being significantly lower
at the nadir of the curve. Light intensity activities (<4.5 METs), however, were
unrelated to stroke risk. CONCLUSIONS: Physical activity is associated with
decreased stroke risk in men. A decreased risk was observed at energy
expenditures of 1000 to 1999 kcal/wk, with further risk decrement seen at 2000 to
2999 kcal/wk but not beyond. Confirmation of the U-shaped relation observed in
these data requires similar observations in other populations.
PMID- 9756581
TI - A randomized, controlled pilot study of a home-based exercise program for
individuals with mild and moderate stroke.
AB - BACKGROUND AND PURPOSE: Many stroke survivors have minimal to moderate
neurological deficits but are physically deconditioned and have a high prevalence
of cardiovascular problems; all of these are potentially modifiable with
exercise. The purposes of this randomized, controlled pilot study were (1) to
develop a home-based balance, strength, and endurance program; (2) to evaluate
the ability to recruit and retain stroke subjects; and (3) to assess the effects
of the interventions used. METHODS: Twenty minimally and moderately impaired
stroke patients who had completed inpatient rehabilitation and who were 30 to 90
days after stroke onset were randomized to a control group or to an experimental
group that received a therapist-supervised, 8-week, 3-times-per-week, home-based
exercise program. The control group received usual care as prescribed by the
patients' physicians. Baseline and postintervention assessments included the Fugl
Meyer Motor Assessment, the Barthel Index of Activities of Daily Living (ADL),
the Lawton Scale of Instrumental ADL, and the Medical Outcomes Study-36 Health
Status Measurement. Functional assessments of balance and gait included a 10-m
walk, 6-Minute Walk, and the Berg Balance Scale. Upper extremity function was
evaluated by the Jebsen Test of Hand Function. RESULTS: Of 22 patients who met
study criteria, 20 completed the study and 2 refused to participate. The
experimental group tended to improve more than the control group in motor
function (Fugl-Meyer Upper Extremity: mean change in score, 8. 4 versus 2.2; Fugl
Meyer Lower Extremity: 4.7 versus -0.9; gait velocity: median change, 0.25 versus
.09 m/s; 6-Minute Walk: 195 versus 114 ft; Berg Balance Score: 7.8 versus 5; and
Medical Outcomes Study-36 Health Status Measurement of Physical Function: 15. 5
versus 9). There were no trends in differences in change scores by the Jebsen
Test of Hand Function, Barthel Index, and Lawton Instrumental ADL Scale.
CONCLUSIONS: This study demonstrated that a randomized, controlled clinical trial
of a poststroke exercise program is feasible. Measures of neurological
impairments and lower extremity function showed the most benefit. Effects of the
intervention on upper extremity dexterity and functional health status were
equivocal. The lasting effects of the intervention were not assessed.
PMID- 9756582
TI - The geographic variation in stroke incidence in two areas of the southeastern
stroke belt: the Anderson and Pee Dee Stroke Study.
AB - BACKGROUND AND PURPOSE: South Carolina and the southeastern United States have
maintained the highest stroke mortality in the country. The Anderson and Pee Dee
Stroke Study is an assessment of cerebrovascular disease incidence in 2
geographically defined communities in the stroke belt. METHODS: Strokes were
identified in the Anderson and Pee Dee areas of South Carolina. All hospitalized
and out-of-hospital deaths occurring during 1990 among the residents of these 2
areas were included. Strokes were classified by an independent panel of
neurologists using a standard protocol that included specific criteria for stroke
and subtypes. RESULTS: The overall age-adjusted stroke incidence rates (per 100
000 population) were significantly higher in the Pee Dee population (293.1)
compared with Anderson (211.2). The geographic differences were more dramatic in
the younger age groups of 35 to 64 years. Likewise, incidence rates for blacks
were nearly twice the rates for whites. The rates in the Pee Dee were higher than
the rates from other studies in the United States and other parts of the world.
Although the stroke subtypes did not vary between the 2 regions, race-sex
differences were identified. CONCLUSIONS: High stroke incidence and disease rates
persist for all 4 race-sex groups in the Southeast and reflect similar risks as
mortality rates. However, geographic variability in stroke rates suggests that
the pattern of disease in the region is not so much a "belt" of increased stroke
in contiguous areas but rather more a "necklace" of different levels of risk.
These results should be useful in the identification of factors associated with
this geographic enigma.
PMID- 9756583
TI - North Carolina stroke prevention and treatment facilities survey: rtPA therapy
for acute stroke.
AB - BACKGROUND AND PURPOSE: North Carolina is situated in the "stroke belt" region of
the United States, an area of the country with a particularly high incidence of
cerebrovascular disease. The North Carolina Stroke Prevention and Treatment
Facilities Survey was carried out to determine the availabilities of a variety of
stroke prevention and treatment services throughout the state. The purpose of the
present study was to determine how widely recombinant tissue-type plasminogen
activator (rtPA) has been adopted for the treatment of patients with acute
ischemic stroke and to determine the characteristics of the medical facilities in
the state offering this therapy. METHODS: A single-page survey was mailed to the
medical center directors of each inpatient medical facility in North Carolina.
Data collected included questions related to the availability of selected basic
and advanced diagnostic tests and procedures, stroke prevention and treatment
programs and services (community stroke awareness program, acute stroke
identification program, acute stroke team, stroke rtPA protocol, stroke care map,
neurologist), and facilities (Stroke Acute Care Unit or equivalent). RESULTS:
Responses were obtained from all 125 inpatient medical facilities in North
Carolina. rtPA stroke protocols were adopted in 54 facilities located in 46 of
the state's 100 counties. Seventy-four percent of the state's population resides
in counties with hospitals providing rtPA treatment. Compared with facilities not
offering rtPA, those with rtPA protocols more commonly sponsored stroke community
awareness programs (41% versus 17%, P=0.003) and more frequently had an organized
stroke team (31% versus 8%, P=0. 001), used stroke care maps (56% versus 17%,
P<0.001), had rapid stroke identification programs (33% versus 6%, P<0.001), or
had a Stroke Acute Care Unit or its equivalent (33% versus 7%, P<0.001).
Neurologists were available in 78% of the facilities offering rtPA compared with
38% in facilities without rtPA protocols (P<0.001). CONCLUSIONS: These data show
that this new therapy for ischemic stroke is potentially available to a high
proportion of the state's citizens based on their county of residence. However,
other services that may improve outcomes and reduce stroke-related costs (eg,
stroke teams, stroke units, care maps) are not being widely used, even in centers
providing treatment with rtPA. The simple methodology used in this study is
potentially applicable in other states and permits targeting of selected centers
for development of stroke treatment capabilities.
PMID- 9756584
TI - Dichotomized efficacy end points and global end-point analysis applied to the
ECASS intention-to-treat data set: post hoc analysis of ECASS I.
AB - BACKGROUND AND PURPOSE: It is not yet known which end points are the most
suitable for evaluation of the effects of acute stroke intervention. The European
Cooperative Acute Stroke Study (ECASS) I study used 2 primary end points. The
study was powered to detect a 15% improvement of the median of each primary end
point. The study failed to show this effect and was negative in the intention-to
treat analysis. The National Institute of Neurological Disorders and Stroke
(NINDS) study used 4 dichotomized end points and applied a global end-point
analysis. This study was positive and led to FDA approval of thrombolytic therapy
for acute ischemic stroke. This study was undertaken to answer the question of
whether a different statistical design may have shown a positive results of the
ECASS I trial. METHODS: We performed a retrospective analysis of the ECASS I
intention-to-treat data set (615 randomized and treated patients, rtPA treatment
versus placebo) and post hoc application of the NINDS trial statistical
methodology (global end-point analysis). The scores of the modified Rankin Scale
(mRS), Barthel Index (BI), and the National Institutes of Health Stroke Scale
(NIHSS) were dichotomized according to the criteria used in the NINDS trial.
Favorable outcome was defined as a score of 0 or 1 on mRS, a score of 95 or 100
on BI, and a score of 0 or 1 on NIHSS. RESULTS: The number of patients reaching
favorable outcome were higher in all 3 end points in the rtPA-treated group. The
effect sizes were 8% for mRS, 6% for BI, and 14% for NIHSS, respectively. The
differences are statistically significant for the mRS (P=0.044; odds ratio [OR],
1. 4; 95% confidence interval [CI], 1.0 to 2.0) and the NIHSS (P=0.001; OR, 1.9;
95% CI, 1.4 to 2.8), while for the BI significance was missed (P=0.102; OR, 1.3;
95% CI, 0.9 to 1.8). The global end-point statistics, however, shows a
significant increase (P=0.008; OR, 1.5; 95% CI, 1.1 to 2.0) of favorable outcome
in the rtPA-treated patient group. CONCLUSIONS: Using the global end-point
analysis, ECASS is positive in the intention-to-treat analysis. This may indicate
that the time window for thrombolysis may be as long as 6 hours. Looking at the 3
dichotomized end points, the effect sizes for 2 end points, mRS and BI, are
smaller in the ECASS 6-hour intention-to-treat population compared with the NINDS
trial, whereas the effect size for the NIHSS is larger. While in the NINDS trial
all 3 end points reveal statistically significant results, in ECASS only 2 of the
3 corresponding end points, mRS and NIHSS, were statistically significant. This
finding underlines an important difference of a global end-point approach: it may
show a positive overall result although one of the end points is not positive.
PMID- 9756586
TI - The CAMCOG: a useful screening instrument for dementia in stroke patients.
AB - BACKGROUND AND PURPOSE: Most mental screening tests focus on the detection of
cognitive deficits compatible with Alzheimer's disease. Stroke patients who
develop a dementia syndrome, however, constitute a more heterogeneous group with
both cortical and subcortical disturbances. We assessed the diagnostic accuracy
of the CAMCOG (the cognitive and self-contained part of the Cambridge Examination
for Mental Disorders of the Elderly) and the Mini-Mental State Examination (MMSE)
for dementia in patients with a recent stroke. METHODS: In patients aged 55 and
older who were admitted in the Rotterdam Stroke Databank, cognitive functioning
was assessed between 3 and 9 months after the most recent stroke. The "gold
standard" diagnosis of dementia was compatible with the criteria of the
Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised.
The CAMCOG and MMSE scores were obtained independent of the diagnostic procedure.
RESULTS: Of 300 consecutive patients, 71 (23.7%) were demented. Sixteen severely
demented patients could not be tested and were excluded. The CAMCOG and MMSE
scores were significantly related to dementia (both P<0.0001) in a logistic
regression model. Receiver operating characteristic analysis showed that the
CAMCOG was a more accurate screening instrument (area under the curve for CAMCOG,
0.95; for MMSE, 0.90). Two other clinical variables independently improved the
diagnostic accuracy of the MMSE and CAMCOG: patients with a left hemispheric
lesion had a lower (odds ratio, 0.3; 95% confidence interval, 0.1 to 0.7), and
patients with hemorrhagic stroke had a greater chance of being demented (odds
ratio, 3; 95% confidence interval, 1 to 10). The effect of left hemispheric
lesion as an independent diagnostic factor could not be explained by selection or
its association with aphasia alone. CONCLUSIONS: The CAMCOG is a feasible
instrument for use in patients with a recent transient ischemic attack or stroke.
It is a more accurate screening tool for dementia than the MMSE, especially when
type and site of stroke are taken into account.
PMID- 9756585
TI - Selective intra-arterial fibrinolysis of acute central retinal artery occlusion.
AB - BACKGROUND AND PURPOSE: Occlusion of the central retinal artery (CRAO) causes a
sudden decrease of monocular vision. Because early restoration of blood flow may
improve outcome, we attempted to treat CRAO with selective intra-arterial
fibrinolysis. METHODS: Intra-arterial fibrinolysis was performed within 6 hours
after symptom onset in 17 patients with thromboembolic CRAO. Symptoms were
painless, acute and severe decrease of vision. Urokinase (100 000 to 900 000 IU)
was given through a microcatheter into the ophthalmic artery over 10 to 90
minutes. For comparison, the history and visual outcome of 15 control patients
who did not receive fibrinolytics were evaluated. In both groups some of the
patients underwent paracentesis and/or received carboanhydrase inhibitors.
RESULTS: Patients who underwent fibrinolysis fared better than control patients
(P=0.01). Three patients (17.6%) recovered completely after fibrinolysis and
regained visual acuity of 20/20 (n=2) to 25/20 (n=1). Two additional patients
(11.8%) showed a marked improvement to a visual acuity of 20/30. In 6 patients
(35. 3%) vision improved slightly. They were able to count fingers, detect hand
movements, or perceive light. In 6 patients (35.3%), fibrinolytic treatment was
without effect. Among control patients, 1 patient (6.7%) showed partial, 4
patients (26.7%) minimal, and 10 (66.7%) no improvement of vision. CONCLUSIONS: A
complete or marked improvement of visual acuity was achieved in one third of
intra-arterial fibrinolysis patients but in none of the control patients. Intra
arterial fibrinolysis seems to have the potential to "lighten" the spontaneously
poor outcome of CRAO.
PMID- 9756587
TI - Incidence and determinants of poststroke dementia as defined by an informant
interview method in a hospital-based stroke registry.
AB - BACKGROUND AND PURPOSE: Inconsistent information about incidence and determinants
of poststroke dementia might be related to patient attrition, partly because of
nonapplicability of formal neuropsychological testing to a large proportion of
patients registered in a definite setting. METHODS: Using a proxy-informant
interview based on ICD-10 criteria, we determined dementia at stroke onset and 1
year after stroke in the 339 patients who survived, were available for follow-up,
and were not demented at stroke onset of 635 patients entered over a 1-year
period in a stroke registry taken at 2 community hospitals in Florence, Italy.
RESULTS: Of the 339 patients, 57 (16.8%) proved to have poststroke dementia.
These patients were older, more frequently female, and more often (multivariate
odds ratio, 2.35; 95% CI, 1.21 to 4.58) had atrial fibrillation than those
without dementia. Aphasia and the clinical features expressing the severity of
the stroke event in the acute phase predicted poststroke dementia. CONCLUSIONS:
In a hospital-based nonselected series of stroke survivors, despite the use of a
method with low sensitivity for defining dementia, our study confirms that
dementia is a frequent sequela of stroke and is mainly predicted by stroke
severity. Certain determinants could be controlled in the prestroke phase, thus
reducing its risk.
PMID- 9756588
TI - Association of stroke with dementia, cognitive impairment, and functional
disability in the very old: a population-based study.
AB - BACKGROUND AND PURPOSE: Stroke is a major cause of disability in the elderly and
is also related to the development of dementia, which is another important source
of disability in old age. The aim of the present study was to examine the
potential impact of stroke on cognitive and functional status in a community
based cohort of individuals aged 75 years and older. METHODS: The data were
derived from a cross-sectional survey on aging and dementia that included all
inhabitants of the Kungsholmen district in central Stockholm who were aged >/=75
years. Cases of stroke were identified through the computerized inpatient
register system that has been widely used to study stroke in Sweden. Dementia was
defined according to the Diagnostic and Statistical Manual of Mental Disorders,
Third Edition, Revised. Dementia onset was considered the appearance, according
to an informant, of the first symptom. Cognitive impairment without dementia was
defined as the presence of a Mini-Mental State Examination score of <24 and the
absence of dementia. Functional disability was assessed according to Katz Index
of independence in activities of daily living. RESULTS: The prevalence of stroke
was 10. 0% in men and 8.0% in women. One third of stroke survivors were diagnosed
as demented, which was 3 times higher than those without stroke: adjusted odds
ratio (OR) was 3.6 (95% confidence interval, 2. 5 to 5.8). Stroke was also
significantly related to cognitive impairment without dementia (adjusted OR, 2.4
[95% confidence interval, 1.3 to 4.6]). The population-attributable risks of
dementia and cognitive impairment in relation to stroke were 18.4% and 8.5%,
respectively. Among the 49 stroke patients with dementia, 15 cases (30.6%) had
missing information on dementia onset, 22 (44. 9%) had been reported by the
informant to have dementia-related symptoms after or close to the occurrence of
stroke, and 12 (24.5%) had symptoms before stroke occurrence. The prevalence
rates of disability in activities of daily living were much higher among stroke
patients than among stroke-free subjects, even after adjustment for age, sex,
heart disease, hip fracture, and dementia: the corresponding adjusted ORs for
bathing, dressing, toileting, transfer, and continence were 3.5 (2.4 to 5.3), 2.2
(1.4 to 3.3), 3. 0 (2.0 to 4.5), 3.3 (1.9 to 5.7), and 2.1 (1.3 to 3.3),
respectively. After dementia and hip fracture, stroke was the third largest
contributor to disability in bathing, dressing, and transfer. Stroke was the
second contributor to disability in toileting. CONCLUSIONS: Stroke is strongly
associated with dementia, although it may relate to dementia in different ways:
it can be the main cause or a precipitating factor of dementia, or they may share
common etiological bases. Together with dementia and hip fracture, stroke is a
major contributor to disability in most aspects of activities of daily living in
very old people.
PMID- 9756589
TI - Effects of acupuncture treatment on daily life activities and quality of life: a
controlled, prospective, and randomized study of acute stroke patients.
AB - BACKGROUND AND PURPOSE: A number of studies have indicated that acupuncture might
improve the functional recovery of stroke patients. These studies vary in
inclusion criteria, sample size, and evaluation methods. The present study was
designed to investigate whether electroacupuncture treatment favorably affects
stroke patients' ability to perform daily life activities, their health-related
quality of life, and their use of health care and social services. METHODS: One
hundred four consecutive patients >40 years of age admitted to hospital because
of an acute stroke were randomized to 3 groups: deep, superficial, and no
acupuncture treatment. The acupuncture treatment given by 4 physiotherapists
started 4 to 10 days after randomization and was given twice a week for 10 weeks.
All patients underwent conventional stroke rehabilitation as well. Two
occupational therapists, blinded regarding the patients' allocation, evaluated
the treatment effects. The assessments were performed 4 times during the first
year after randomization by means of interviews and observations. RESULTS: There
were no differences between the groups with reference to changes in the
neurological score and the Barthel and Sunnaas activities of daily living index
scores after 3 and 12 months. Regarding the Nottingham Health Profile, the no
acupuncture group had somewhat fewer mobility problems. No differences in health
care and social services were found between the groups. CONCLUSIONS: The present
study does not give support to the previous studies, which indicates that
acupuncture treatment may have a beneficial effect on acute stroke patients'
ability to perform daily life activities, their health-related quality of life,
and their use of health care and social services.
PMID- 9756590
TI - Incidence of transient ischemic attack in Rochester, Minnesota, 1985-1989.
AB - BACKGROUND AND PURPOSE: There is scant information available on the incidence of
transient ischemic attack (TIA) in a defined population. This study defines
incidence rates of first TIA and subtypes of TIA during 1985-1989 and compares
the incidence to that obtained from a 1960-1972 cohort study. METHODS: Medical
records of all residents of Rochester with potential diagnosis of TIA during 1985
1989 were screened to determine whether the case met the criteria for TIA. All
available data were used to determine the vascular distribution of the TIA.
Average annual age- and sex-adjusted incidence rates were calculated for 1985
1989, and results were compared with incidence rates determined in a Rochester
based 1960-1972 cohort study. RESILTS: Two hundred two cases of first TIA or
amaurosis fugax occurred among Rochester residents during 1985-1989. The age- and
sex-adjusted incidence rate for any TIA was 68/100 000 population. Incidence of
amaurosis fugax was 13/100 000; anterior circulation (cerebral) TIA, 38/100 000;
and vertebrobasilar distribution TIA, 14/100 000. Rates were similar to those
determined from a 1960-1972 cohort study. CONCLUSIONS: The incidence rate of TIA
is 41% that of stroke incidence. TIA incidence in Rochester, Minn, is higher than
has been previously reported for other sites throughout the world. Although
comparison with prior time periods is difficult because of ascertainment issues,
it appears that there has been no significant change in TIA incidence since the
decade of the 1960s or earlier. This suggests that the most common mechanism for
TIA (atherosclerosis) has not changed in prevalence, nor have risk factors
leading to this mechanism.
PMID- 9756591
TI - Three-year survival and recurrence after stroke in Malmo, Sweden: an analysis of
stroke registry data.
AB - BACKGROUND AND PURPOSE: Data from the Malmo Stroke Registry were analyzed to
determine whether any change in survival or nonfatal stroke recurrence rates had
occurred during the 4-year period from 1989 through 1992 and whether prognosis
was related to area of residence. METHODS: The series comprised 2290 patients,
1051 men and 1239 women, followed up for 3 years after their first stroke during
the period 1989 through 1992. RESULTS: Of the series as a whole, 959(43.4%) died
and 137(6%) suffered a second nonfatal stroke. Multivariate analysis showed age,
type of stroke, severity of stroke, and the presence of diabetes mellitus or
cardiac disease each to be an independent predictor of mortality, and the
presence of diabetes, atrial fibrillation, and history of transient ischemic
attacks each to be associated with increased risk of recurrence. Treatment for
hypertension was associated with a protective effect. As compared to those with
first stroke in 1989, those with first stroke in 1992 were characterized by a
lower recurrence rate, which was reduced by 70% in the male subgroup (P=0.003)
and by 80% in the female subgroup (P=0.006), the corresponding reduction in all
cause mortality being 30% (P=0.007) and 10% (P=0.5, NS). Recurrence-free survival
rates differed markedly between the 17 residential areas studied. CONCLUSIONS:
The present study showed that survival rates after stroke have improved and
recurrence rates have declined in this urban population. Further studies are
needed to ascertain to what extent intraurban variation in the proportion of
recurrence-free 3-year survivors is to be explained by differences in the
severity of initial stroke and other prognostic markers, or in initial treatment
and secondary preventive measures.
PMID- 9756592
TI - Risk factors for early recurrence after ischemic stroke: the role of stroke
syndrome and subtype.
AB - BACKGROUND AND PURPOSE: Information regarding risk factors for early recurrence
is limited. Our aim was to identify the clinical predictors of early recurrence
after ischemic stroke. METHODS: We prospectively examined 297 patients (mean age,
72.0+/-8.4 years) hospitalized with ischemic stroke to identify recurrent strokes
occurring within 90 days of the index stroke. Survival free of recurrence was
estimated using Kaplan-Meier analysis stratified by demographic variables;
vascular risk factors; stroke syndrome, subtype, vascular territory, and
severity; scores on the Barthel Index and Mini-Mental State Examination during
hospitalization; blood pressure on admission; and selected laboratory data. We
estimated the relative risk (RR) of early recurrence associated with those
variables using proportional hazards analysis. RESULTS: We identified 22
recurrent events in the first 90 days after the index stroke, resulting in an
early stroke recurrence rate of 7.4%, and death occurred immediately after
recurrence in 6 of the 22 patients. A major hemispheric stroke syndrome (RR=2.9;
95% confidence interval [CI]=1.2 to 7.1), atherothrombotic stroke mechanism
(RR=3.3; CI=1.3 to 8.3), and atrial fibrillation (RR=2.2; CI=0.8 to 6.1) were
independent predictors of early recurrence, after adjustment for demographic
variables. Conclusions-Early recurrence was frequent and resulted in increased
mortality. Attention to the clinical features of the index stroke, including the
presenting syndrome and the ischemic mechanism, and the recognition of atrial
fibrillation may help in the selection of patients for the initiation of targeted
interventions to prevent early recurrence and subsequent mortality.
PMID- 9756593
TI - Microembolic signals and risk of early recurrence in patients with stroke or
transient ischemic attack.
AB - BACKGROUND AND PURPOSE: Asymptomatic microembolic signals (MES) can be
demonstrated in patients with cerebral ischemia using transcranial Doppler (TCD)
ultrasonographic monitoring of the middle cerebral artery. However, the clinical
relevance of MES remains uncertain. The purpose of this study was to estimate the
independent contribution of microembolism to the risk of early ischemic
recurrence (EIR) in patients with stroke or transient ischemic attack (TIA) of
presumed arterial origin. METHODS: We studied the incidence of EIR in 73
consecutive patients with carotid stroke or TIA in whom TCD scanning of the
symptomatic middle cerebral artery was performed within 7 days from the onset of
symptoms. Patients with a potential cardiac source of embolism were excluded from
the study. RESULTS: Eight patients had EIR during a mean+/-SD follow-up of 10+/-8
days. The incidence of EIR was 4.3 per 100 patient-days in patients with MES and
only 0.5 per 100 patient-days in patients without MES. The presence of MES was a
significant predictor of EIR after adjustment for the presence of carotid
stenosis or aortic arch atheroma, antiplatelet therapy during follow-up, and
other potential confounding variables (relative risk, 8.7; 95% confidence
interval, 2 to 38.2; P=0.0015). CONCLUSIONS: Microembolism is a significant
independent predictor of EIR in patients with stroke or TIA of presumed arterial
origin.
PMID- 9756594
TI - A longitudinal prospective study of soluble adhesion molecules in acute stroke.
AB - BACKGROUND AND PURPOSE: Activation of endothelial cells is a consequence of
cerebral ischemia and leads to the expression of adhesion molecules such as
intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1
(VCAM-1), and E-selectin, which can be released into the blood. This study aimed
to define the kinetics of soluble adhesion molecule serum levels after cerebral
ischemia and their correlation with the extent of neurological deficits, clinical
outcome, and infarct volume as measured on CT scans. Methods-Plasma levels of
soluble (s) ICAM-1, sVCAM-1, and sE-selectin were repeatedly determined by ELISA
in 38 patients during a period of 14 days after acute cerebral ischemia. RESULTS:
Soluble adhesion molecule levels demonstrated considerable variability. Overall,
concentrations revealed characteristic and significant changes after completed
strokes but not after transient ischemic attacks. In patients with completed
stroke (n=26) but not in patients with transient ischemic attacks (n=12), sICAM-1
peaked within 24 hours (P=0.04), sVCAM-1 reached a maximum after 5 days (P=0.02),
and sE-selectin levels decreased after 5 days (P=0.002). There was no clear-cut
correlation of soluble adhesion molecule levels with infarct volume or clinical
disability. The initial increase of sE-selectin levels was higher in more
disabled patients (P=0.02). sICAM-1 levels were higher in patients with signs of
infection (n=9; P=0.03). CONCLUSIONS: As a result of large interindividual
variability influenced by ischemia-independent factors, soluble adhesion
molecules are not reliable candidates as surrogate markers in acute cerebral
ischemia. The characteristic profile of individual soluble adhesion molecules
after completed stroke supports prior hypotheses of their involvement in the
pathogenesis of acute cerebral ischemia, but this needs to be clarified in
detail.
PMID- 9756595
TI - Citicoline treatment for experimental intracerebral hemorrhage in mice.
AB - BACKGROUND AND PURPOSE: Citicoline sodium (cytidine-5'-diphosphocholine) has been
shown previously to reduce ischemic injury in focal central nervous system
models. Intracerebral hemorrhage (ICH) appears to be associated with an area of
edema and ischemic injury surrounding the hematoma that may be reduced by
neuroprotective therapy. The present study was designed to test whether treatment
with citicoline reduces ischemic injury and improves functional neurological
outcome in an experimental model of ICH. METHODS: In 68 Swiss albino mice (26 to
36 g), ICH was induced by collagenase injection into the caudate nucleus. Animals
were randomized to receive either: citicoline 500 mg/kg or saline IP prior to
collagenase and at 24 and 48 hours. Animals were rated on a 28-point neurological
scale and sacrificed at 54 hours. The brains were sectioned, and the volume of
hematoma, total lesion, and surrounding ischemic injury was determined. RESULTS:
In terms of functional outcome, animals treated with citicoline had improved
neurological outcome scores compared with placebo-treated animals: 10.4+/-2.0
versus 12.1+/-2.4 (P<0.01). Regarding ischemic injury, although there was no
difference in the underlying hematoma volumes, animals treated with citicoline
had a smaller surrounding volume of ischemic injury than placebo-treated animals:
citicoline, 13.8+/-5.8 mm3 (10.8+/-4.3% of hemisphere); placebo, 17.0+/-7.1 mm3
(13.3+/-5. 1%) (P<0.05). CONCLUSIONS: In this animal model of ICH, treatment with
citicoline significantly improved functional outcome and reduced the volume of
ischemic injury surrounding the hematoma. This study supports a potential role
for citicoline in clinical ICH treatment.
PMID- 9756596
TI - YM872, a highly water-soluble AMPA receptor antagonist, preserves the hemodynamic
penumbra and reduces brain injury after permanent focal ischemia in rats.
AB - BACKGROUND AND PURPOSE: We recently described an image analysis technique based
on the temporal correlation mapping (TCM) of injected contrast agents that can be
used to distinguish the hemodynamic core and hemodynamic penumbra after focal
ischemia. In this study we used this technique for the first time to investigate
the effects of the water-soluble AMPA receptor antagonist YM872 in permanent
focal ischemia. METHODS: Fischer 344 rats were subjected to permanent occlusion
of the middle cerebral artery. Approximately 30 minutes after ischemia,
functional CT images were collected with the use of a dynamic scanning protocol
with bolus injections of nonionic contrast agent iohexol (1 mL/kg). TCM analysis
defined the distributions of hemodynamic core and hemodynamic penumbra. Cerebral
perfusion indices were calculated on the basis of the area under the first-pass
transit curves. One hour after ischemia, animals were randomly treated with YM872
(n=8, 20 mg/kg per hour over 4 hours) or normal saline (n=10). Twenty-four hours
later, neurological deficits were evaluated, and conventional CT and
triphenyltetrazolium chloride staining were used to define volumes of ischemic
damage. RESULTS: At 24 hours after ischemia, hypodense lesions were visible on
conventional CT scans that were highly correlated with triphenyltetrazolium
chloride lesion volumes. YM872 improved neurological deficits and reduced volumes
of ischemic damage in cortex (90+/-14 versus 170+/-16 mm3 in controls) but not
striatum (57+/-14 versus 79+/-6 mm3 in controls). Comparison of early TCM images
with conventional CT scans of ischemic injury showed that the hemodynamic core
was always damaged in all rats. In controls, 54% of the tissue within the
hemodynamic penumbra evolved into ischemic damage compared with 24% in YM872
treated rats. Furthermore, the perfusion index corresponding to the ischemic
damage threshold was significantly reduced by YM872 (28+/-2% versus 37+/-2% in
controls). CONCLUSIONS: These results indicate that YM872 is a neuroprotective
compound that ameliorates the deterioration of the hemodynamic penumbra after
focal ischemia.
PMID- 9756597
TI - Myosin light chain phosphorylation and contractile proteins in a canine two
hemorrhage model of subarachnoid hemorrhage.
AB - BACKGROUND AND PURPOSE: Subarachnoid hemorrhage (SAH) impairs both contraction
and relaxation response in cerebral arteries. We tested the hypothesis that
cerebral vasospasm might be ATP-independent contraction, such as latch state, and
protein synthesis might be substantially downregulated due to ATP consumption
after long-lasting contraction. METHODS: Chronic cerebral vasospasm was induced
in the canine 2-hemorrhage model of SAH. The normal and spastic basilar arteries
were stabilized in Krebs-Henseleit solution, and contraction was induced by 30
micromol/L prostaglandin F2alpha (PGF2alpha) in vitro and in vivo. Before and at
15 minutes and 1 hour after the treatment with PGF2alpha, the levels of
phosphorylated 20-kDa myosin light chain (MLC20) were measured. The time course
of expression of contraction proteins actin and MLC20, and contraction-inhibiting
proteins h-caldesmon and calponin was determined by immunoblotting techniques.
RESULTS: A significant vasospasm occurred in the basilar artery during days 4 to
21, most prominently on days 7 and 14. There were no significant differences in
the baseline levels of phosphorylated MLC20 between normal and spastic basilar
arteries. The increase in MLC20 phosphorylation by PGF2alpha was significantly
attenuated in the spastic basilar artery in vitro and in vivo (P<0.05). The
immunoreactivity for actin, h-caldesmon, and calponin in the spastic basilar
arteries was progressively decreased until day 14 and returned to the normal
level on day 21. In contrast, protein levels of MLC20 did not significantly
change during days 0 to 21. CONCLUSIONS: Chronic cerebral vasospasm closely
resembles the latch state, and temporary deficiencies of contractile proteins may
result from increased destruction and inhibition of protein synthesis.
PMID- 9756599
TI - A critical reevaluation of the intraluminal thread model of focal cerebral
ischemia: evidence of inadvertent premature reperfusion and subarachnoid
hemorrhage in rats by laser-Doppler flowmetry.
AB - BACKGROUND AND PURPOSE: The intraluminal thread model for middle cerebral artery
occlusion (MCAO) has gained increasing acceptance. Numerous modifications have
been reported in the literature, indicating that the technique has not been
standardized. The present study was performed to evaluate and optimize the
reliability of this model. METHODS: One hundred Sprague-Dawley rats were
subjected to MCAO by 2 different intraluminal filaments. Cortical blood flow was
continuously monitored over both hemispheres by laser-Doppler flowmetry (LDF). In
part I (3-0 filament), we evaluated the incidence of adequate MCAO, subarachnoid
hemorrhage (SAH), intraluminal thrombus formation, and the effects of
heparinization. In part II (silicone-coated 4-0 filament), we also determined the
influence of insufficient MCAO on morphological and functional outcome and the
incidence of postischemic hyperthermia. RESULTS: In part I, SAH occurred in 30%
and premature reperfusion in 24%. All animals with a decrease in contralateral
flow had suffered SAH. Thrombus formation was not observed in any group. In part
II, SAH occurred in 8% and premature reperfusion in 26%. There was no difference
in outcome between rats with primary MCAO and rats with filament correction.
Animals with uncorrected premature reperfusion had significantly smaller infarct
volumes and fewer neurological deficits. CONCLUSIONS: SAH and insufficient MCAO
may be more common in the intraluminal thread model than previously reported.
Inadvertent premature reperfusion contributes to the interanimal variability
associated with this model. The incidence of valid experiments increases with the
use of a silicone-coated 4-0 filament. Continuous bilateral LDF is indispensable
to monitor adequate MCAO and is highly sensitive to recognize SAH.
PMID- 9756598
TI - Diffusion MR imaging during acute subarachnoid hemorrhage in rats.
AB - BACKGROUND AND PURPOSE: We analyzed the temporal and spatial pattern of water
diffusion changes during acute subarachnoid hemorrhage (SAH) in rat brain to
identify factors contributing to the acute pathophysiology of SAH. METHODS:
Subarachnoid hemorrhage was remotely induced via perforation of the circle of
Willis with an endovascular suture during MR imaging. A fast echo-planar imaging
technique was used to acquire 60 maps of the apparent diffusion coefficient (ADC)
beginning 1 min before and continuing for 11 min after induction of SAH. A high
resolution spin-echo diffusion sequence was used to follow diffusion changes over
6 h after SAH. Sham-operated control (n=3), nonheparinized (n=6), and heparinized
(n=5) groups were studied. RESULTS: Sham-operated control animals did not show
ADC changes over time. In both SAH groups, however, a sharp decline of ADC within
2 min of SAH was consistently observed in the ipsilateral somatosensory cortex.
These decreases in diffusion then spread within minutes over the ipsilateral
hemisphere. Similar ADC decreases on the contralateral side started with a
further time delay of 1 to 3 min. From 30 min onward, the extent of the diffusion
abnormality decreased progressively in the nonheparinized animals. No recovery
was observed in heparinized rats. CONCLUSIONS: MR diffusion imaging allows new
insight into the pathophysiology of acute SAH: The spatial and temporal pattern
of diffusion changes suggests the initial occurrence of acute vasospasm and
subsequently "spreading depolarization" of brain tissue. Persistent hemorrhage in
heparinized animals was reflected by early decline of ADC values throughout the
entire brain.
PMID- 9756600
TI - Optimal depth and duration of mild hypothermia in a focal model of transient
cerebral ischemia: effects on neurologic outcome, infarct size, apoptosis, and
inflammation.
AB - BACKGROUND AND PURPOSE: Mild hypothermia is possibly the single most effective
method of cerebroprotection developed to date. However, many questions regarding
mild hypothermia remain to be addressed before its potential implementation in
the treatment of human stroke. Here we report the results of 2 studies designed
to determine the optimal depth and duration of mild hypothermia in focal stroke
and its effects on infarct size, neurological outcome, programmed cell death, and
inflammation. METHODS: Rats underwent a 2-hour occlusion of the left middle
cerebral artery. In the first study (I) animals were kept (intraischemically) at
either 37 degreesC (n=8), 33 degreesC (n=8), or 30 degreesC (n=8). Study II
consisted of 4 groups: (1) controls (37 degreesC, n=10), (2) 30 minutes of
hypothermia started at ischemic onset (33 degreesC, n=9), (3)1 hour (33 degreesC,
n=8), and (4) 2 hours (33 degreesC, n=8). Brain temperature was measured by a
thermocouple probe placed in the contralateral cortex. After suture removal, all
animals were rewarmed and reperfused for 22 hours (I) or 70 hours (II). RESULTS:
Mild hypothermia to 33 degreesC or 30 degreesC was neuroprotective (17+/-7% and
27+/-6%, respectively) relative to controls (53+/-8%, P<0.02), but 33 degreesC
was better tolerated and recovery from anesthesia was faster. The neurological
score of hypothermic animals was significantly better than that of controls (I &
II) at both 24 and 72 hours postischemia except for the 30-minute group (II),
which showed no improvement. In Study II, 2 hours of hypothermia reduced injury
by 59%, 1 hour reduced injury by 84% whereas 30 minutes did not reduce injury.
Normalized for infarct size, 2 hours of mild hypothermia decreased neutrophil
accumulation by 57% whereas both 1 hour and 30 minutes had no effect. At 72
hours, 1 and 2 hours of mild hypothermia decreased transferase dUTP nick-end
labeling (TUNEL) staining by 78% and 99%, respectively, and 30 minutes of
hypothermia had no effect. CONCLUSIONS: Intraischemic mild hypothermia must be
maintained for 1 to 2 hours to obtain optimal neuroprotection against ischemic
cell death due to necrosis and apoptosis.
PMID- 9756601
TI - Cationic polymer and lipids enhance adenovirus-mediated gene transfer to rabbit
carotid artery.
AB - BACKGROUND AND PURPOSE: Improvement of efficiency of gene transfer to endothelium
could be useful for several applications. We tested the hypothesis that cationic
nonviral molecules augment adenovirus-mediated gene transfer to blood vessels,
perhaps by alteration of the surface charge of adenovirus and facilitation of
binding to endothelium. METHODS: Carotid arteries from rabbits were incubated in
vitro for 0.5 to 2 hours with an adenoviral vector alone or noncovalent complexes
of adenovirus with poly-L-lysine (a cationic polymer) or lipofectin (a cationic
lipid). Binding of adenovirus to the vessels was evaluated immediately after
incubation with virus, and assay of transgene (ss-galactosidase) activity and
histochemistry were performed 24 hours after gene transfer. To determine whether
cationic molecules can be used to augment alteration of vascular function by
adenovirus-mediated gene transfer, we also examined effects on gene transfer of
endothelial nitric oxide synthase. RESULTS: Assay of ss-galactosidase activity
indicated that both cationic molecules increased transgene expression in vessels
by approximately 5- to 6-fold. In contrast, when endothelium was removed from the
vessels after gene transfer, poly-L-lysine and lipofectin did not significantly
increase transgene activity. Histochemistry for ss-galactosidase also suggested
that the adenovirus-cationic molecule complexes augmented transgene expression
mainly in the endothelium. In addition, we found that complexing adenovirus with
cationic molecules increased binding of adenovirus to the vessels. After gene
transfer with recombinant adenovirus containing endothelial nitric oxide
synthase, calcium ionophore (A23187) produced greater relaxation of vessels
treated with adenovirus complexed with poly-L-lysine or lipofectin than those
treated with adenovirus alone. CONCLUSIONS: Cationic molecules improve the
efficiency of adenovirus-mediated gene transfer to blood vessels.
PMID- 9756602
TI - Matrix metalloproteinases and TIMPs are associated with blood-brain barrier
opening after reperfusion in rat brain.
AB - BACKGROUND AND PURPOSE: Reperfusion disrupts cerebral capillaries, causing
cerebral edema and hemorrhage. Middle cerebral artery occlusion (MCAO) induces
the matrix-degrading metalloproteinases, but their role in capillary injury after
reperfusion is unknown. Matrix metalloproteinases (MMPs) and tissue inhibitors to
metalloproteinases (TIMPs) modulate capillary permeability. Therefore, we
measured blood-brain barrier (BBB) permeability, brain water and electrolytes,
MMPs, and TIMPs at multiple times after reperfusion. METHODS: Adult rats
underwent MCAO for 2 hours by the suture method. Brain uptake of 14C-sucrose was
measured from 3 hours to 14 days after reperfusion. Levels of MMPs and TIMPs were
measured by zymography and reverse zymography, respectively, in contiguous
tissues. Other rats had water and electrolytes measured at 3, 24, or 48 hours
after reperfusion. Treatment with a synthetic MMP inhibitor, BB-1101, on BBB
permeability and cerebral edema was studied. RESULTS: Brain sucrose uptake
increased after 3 and 48 hours of reperfusion, with maximal opening at 48 hours
and return to normal by 14 days. There was a correlation between the levels of
gelatinase A at 3 hours and the sucrose uptake (P<0.05). Gelatinase A (MMP-2) was
maximally increased at 5 days, and TIMP-2 was highest at 5 days. Gelatinase B and
TIMP-1 were maximally elevated at 48 hours. The inhibitor of gelatinase B, TIMP
1, was also increased at 48 hours. Treatment with BB-1101 reduced BBB opening at
3 hours and brain edema at 24 hours, but neither was affected at 48 hours.
CONCLUSIONS: The initial opening at 3 hours correlated with gelatinase A levels
and was blocked by a synthetic MMP inhibitor. The delayed opening, which was
associated with elevated levels of gelatinase B, failed to respond to the MMP
inhibitor, suggesting different mechanisms of injury for the biphasic BBB injury.
PMID- 9756603
TI - beta-Amyloid precursor protein and ss-amyloid peptide immunoreactivity in the rat
brain after middle cerebral artery occlusion: effect of age.
AB - BACKGROUND AND PURPOSE: Previous studies have shown that the ss-amyloid precursor
protein (ssAPP) is upregulated after cerebral ischemia and that the ss-amyloid
(Ass) fragment may be toxic to brain cells. Although stroke in humans usually
afflicts the elderly, most experimental studies on the nature of cerebral
ischemia have used young animals. To test the hypothesis that the upregulation
and/or persistence of amyloidogenic proteins is exacerbated in aged rats after
cerebral ischemic stroke, we studied the expression of ssAPP and its proteolytic
product Ass in the brains of young and old rats 7 days after temporary cerebral
ischemia. METHODS: Focal cerebral ischemia was produced by reversible occlusion
of the right middle cerebral artery in 3- and 20-month-old male Sprague-Dawley
rats. After 1 week, brains were removed and immunostaining was performed for
ssAPP, Ass, and ED1 for macrophages and glial fibrillary acidic protein (GFAP).
RESULTS: Histological staining revealed that the degree of necrotic cavitation in
the infarct core was relatively less in aged rats than in young rats, suggesting
a slower pace of degenerative change and/or tissue removal in older animals.
ssAPP immunoreactivity was robustly increased, primarily in macrophage-like, ED1
positive cells in the infarct core and in the penumbra of both young and aged
animals. Ass immunoreactivity was evident in GFAP-positive astrocytic somata and
processes, and also in clusters of small spherical structures in the penumbra.
These Ass-immunoreactive minispheres were more numerous in aged rats than in
young rats. CONCLUSIONS: The presence of ssAPP and Ass immunoreactivity in the
infarct core and penumbra indicates that cerebral ischemia promotes conditions
that are favorable to the focal accumulation of ssAPP and its proteolytic
fragments, especially in the aged brain.
PMID- 9756604
TI - Quality of full and final publications reporting acute stroke trials: a
systematic review.
AB - BACKGROUND AND PURPOSE: Several studies have shown that the quality of reporting
of trials throughout medicine is variable and often poor. We report on the
quality of the final reports of randomized controlled trials (RCTs) of drug
therapies assessed in acute stroke. METHODS: English-language reports published
up to the end of 1996 relating to completed RCTs in acute stroke were identified
from electronic searches of the Cochrane Stroke Review Group database of stroke
trials and the Cochrane Controlled Trials Register (CD-ROM issue 1, 1997, of the
Cochrane Library). Report quality was assessed with the 33 criteria of the
CONSORT statement and 53 additional factors relevant to acute stroke or trials in
general. Trial quality was also assessed with a 7-point scale. RESULTS: Up to
1996, 114 RCTs were published which involved 20 536 patients (median, 80; range,
16 to 1267 per trial); 39 (35.5%) of these were published in Stroke. The median
total report quality was 40/86 (range, 15 to 61) for all criteria and 19/33
(range, 9 to 29) for the CONSORT criteria alone. Although adequate information
was given in the introduction and discussion sections of most reports,
insufficient details were given on methods, assignment of patients to treatment
groups, statistical analyses, the prevalence of risk factors, and assessment of
outcomes. Report quality has improved between 1956 and 1996 (Spearman correlation
coefficient [rs], 0.575; 95% confidence interval [CI], 0. 439 to 0.685) and was
superior in large trials (rs=0.434; 95% CI, 0. 274 to 0.571). Although report
quality was related to trial quality (rs=0.675; 95% CI, 0.563 to 0.763), it was
not related to journal impact factor (rs=0.170; 95% CI, -0.015 to 0.344). Trials
with a positive outcome tended to be less well reported than those with a neutral
or negative outcome (rs=-0.192; 95% CI, -0.351 to -0.011). CONCLUSIONS: The
overall quality of study reports for parallel group RCTs in acute stroke is poor
but appears to be improving with time and in parallel with an increase in trial
size. Reports often lack detailed information on the methods of randomization,
concealment of allocation, and statistical analysis, all factors which can, if
undertaken poorly, affect trial results and validity. It is vital that future
trials are adequately reported; we believe that authors should follow the CONSORT
guidelines and that referees and editors should ensure this happens.
PMID- 9756605
TI - Evaluation of carotid artery stenosis by power doppler imaging.
PMID- 9756606
TI - Evaluation of carotid artery stenosis by power doppler imaging
PMID- 9756608
TI - Abstracts of literature
PMID- 9756607
TI - Two chinese patients with vertebrobasilar dolichoectasia.
PMID- 9756609
TI - The following is a list of major ongoing studies about stroke. Information about
other multicenter studies that might be included in this list should be submitted
to the stroke editorial office by the principal investigator. The list will
appear in the february, june, and october issues of stroke
PMID- 9756610
TI - Roles of aggrecan, a large chondroitin sulfate proteoglycan, in cartilage
structure and function.
AB - Aggrecan, a large aggregating proteoglycan, is one of the major structural
components of cartilage. Its core protein contains three glubular domains and two
glycosaminoglycan-attachment domains. These domains play various roles to
maintain cartilage structure and function. An N-terminal globular domain binds
hyaluronan and link protein to form huge aggregates. The chondroitin sulfate (CS)
chains attach to the CS domain and provide a hydrated, viscous gel that absorbs
compressive load. Two autosomal recessive chondrodysplasias, cartilage matrix
deficiency (cmd) in mice and nanomelia in chicken are both caused by aggrecan
gene mutations. Cmd homozygotes die shortly after birth, while the heterozygotes
are born normal. However, cmd heterozygotes develop late onset of spinal
disorder, which suggests aggrecan as a candidate gene predisposing individuals to
spinal problems. Nanomelia is a useful model to elucidate intracellular
trafficking of proteoglycans. Further studies on aggrecan will lead to
prophylaxis and treatment of joint destructive diseases such as osteoarthrosis
and to elucidation of cartilage development, which is essential for skeletal
formation.
PMID- 9756611
TI - CYP51-like gene of Mycobacterium tuberculosis actually encodes a P450 similar to
eukaryotic CYP51.
AB - A CYP51-like gene (Z80226) of Mycobacterium tuberculosis was expressed in
Escherichia coli. The product exhibited absorption spectra characteristic of
P450. The expressed P450 formed a stoichiometric complex with ketoconazole, one
of the specific ligands of CYP51. These findings indicate that the CYP51-like
gene of M. tuberculosis actually encodes a P450 having active-site environments
similar to those of CYP51, confirming the predicted orthologous nature of this
gene to eukaryotic CYP51. Although eukaryotic CYP51s are membrane-binding
proteins, the expressed product was accumulated only in the soluble fraction of
the host cells.
PMID- 9756612
TI - Cationic liposome-mediated efficient induction of type I interferons by a low
dose of poly I:poly C in mouse cell lines.
AB - Double-stranded polyriboinosinic acid:polyribocytidylic acid (poly I:poly C) is a
powerful inducer of type I interferons (IFNs). However, the dose of poly I:poly C
required for efficient IFN induction is so high as occasionally to be cytotoxic.
In this work, we examined the IFN-inducibility of poly I:poly C complexed with
several cationic reagents in mouse fibroblast L cells and found that Lipofectin
and LipofectACE can induce the production of a substantial amount of type I IFNs
(mostly beta-type) even at a two-order lower dose compared with poly I:poly C
alone. Such effects of poly I:poly C were optimal at 0.1 microgram/ml for 2-10
microgram/ml of Lipofectin and LipofectACE. These conditions caused no
significant cytotoxicity in the recipient cells. Furthermore, a short treatment
(less than 10 min) with the complexes was sufficient for the maximum induction.
This IFN induction method was applicable to other cell types and other species
including human. Hence, our observations may pave the way for clinical
application of the IFN inducer.
PMID- 9756613
TI - Kinetics of slow reversible inhibition of human muscle creatine kinase by planar
anions.
AB - The toxicity of NO3- and NO2- to mammals has been widely publicized. However, the
kinetic mechanism of inhibition of human muscle creatine kinase by NO3- and NO2-
has not been explored. The kinetic theory of the substrate reaction during the
modification of enzyme activity previously described by Tsou (Adv. Enzymol.
Related Areas Mol. Biol. 1988, 61, 381-436) has been applied to a study of the
kinetics of slow reversible inhibition of human muscle creatine kinase by planar
anions (NO3- and NO2-). The kinetic equation of the substrate reaction was
derived from theoretical analysis and experimental data, then simplified. The
microscopic rate constants for the reaction of the inhibitors with the enzyme
were obtained from the simplified equation for the substrate reaction in the
presence of the inhibitors. The results show that the apparent forward rate
constant A is dependent on ATP concentration, indicating competition between the
inhibitor (NO3- or NO2-) and ATP. The results also suggest that binding of
creatine-MgADP and the anion with the enzyme is very tight, since their binding
constants are much higher than those for normal substrates.
PMID- 9756614
TI - Substrate specificity of human monoamine (M)-form phenol sulfotransferase:
preparation and analysis of Dopa 3-O-sulfate and Dopa 4-O-sulfate.
AB - Upon two-dimensional thin-layer separation, the sulfated L-3, 4
dihydroxyphenylalanine (L-DopaS) generated enzymatically was found to co-migrate
with only one of the two ninhydrin-stained spots corresponding to the two
sulfated forms (3-O-sulfate and 4-O-sulfate) of synthetic L-DopaS. To clarify
precisely the identity of the enzymatically generated L-DopaS, the two sulfated
forms of synthetic L-DopaS were separated and purified using high performance
liquid chromatography. Purified L-Dopa 3-O-sulfate and L-Dopa 4-O-sulfate were
identified by 1H-nuclear magnetic resonance (NMR) spectrometry and used as
standards in the analysis of the L-DopaS generated during metabolic labeling of
HepG2 human hepatoma cells or enzymatic assay using recombinant human monoamine
(M)-form phenol sulfotransferase. The results obtained demonstrated unequivocally
the generation of L-Dopa 3-O-sulfate, indicating the specificity of the M-form
phenol sulfotransferase being for the meta-hydroxyl group of L-Dopa.
PMID- 9756615
TI - Kinetic measurement of the interaction between a lysozyme and its immobilized
substrate analogue by means of surface plasmon resonance.
AB - A method for evaluating the association and dissociation rate constants of
interaction between a lysozyme and its substrate analogue, an immobilized p
aminophenyl-tri-N-acetyl-beta-chitotrioside, by means of surface plasmon
resonance has been developed. Site-specific immobilization of p-aminophenyl-tri-N
acetyl-beta-chitotrioside, which is a product of p-nitrophenyl-tri-N-acetyl-beta
chitotrioside, on carboxymethyldextran linked to the surface of the cuvette of
the instrument, IAsys, was carried out by catalysis with EDC/NHS. The kinetic
parameters of the interaction between hen or human lysozyme and the immobilized
substrate analogue indicated that a larger dissociation constant of the human
lysozyme-immobilized substrate analogue complex depended on a smaller association
rate constant. The kinetic parameters of the interaction between the immobilized
substrate analogue and a mutant hen lysozyme, in which Arg14 and His15 are
deleted, with higher activity than the wild type hen lysozyme were measured. It
was suggested that the higher activity of the mutant lysozyme was due to faster
removal of the substrate from the active site cleft and/or the formation of a
stabler and better complex as to hydrolysis.
PMID- 9756616
TI - Isolation of the gene and characterization of the enzymatic properties of a major
exoglucanase of humicola grisea without a cellulose-binding domain.
AB - An exoglucanase gene was cloned from a cellulolytic fungus, Humicola grisea. DNA
sequencing of this gene, designated as exo1, revealed that it contained four
introns in the coding region. The deduced amino acid sequence of EXO1 was 451
amino acids in length and showed 57.7% identity with that of H. grisea
cellobiohydrolase 1 (CBH1), but lacked the typical domain structures of a
cellulose-binding domain and a hinge region. Transcriptional analysis of the exo1
and cbh1 genes showed that the expression of these genes was induced by Avicel,
and repressed in the presence of glucose. The exo1 gene was expressed in
Aspergillus oryzae, and the recombinant EXO1 protein was purified. EXO1 and CBH1
produced by A. oryzae showed relatively higher activity toward Avicel, but showed
much lower activity toward carboxymethyl cellulose (CMC) and p-nitrophenyl-beta-D
cellobioside (PNPC), than H. grisea endoglucanase 1 (EGL1). The addition of a
cellulose-binding domain and a hinge region to EXO1 caused decreases in its
enzymatic activities as well as the deletion of the cellulose-binding domain from
CBH1. EXO1 showed relatively weak or no synergistic activity toward Avicel with
H. grisea endoglucanases, but showed a significant level of apparent synergism
with H. grisea CBH1 and Trichoderma reesei EGLI. CBH1 showed a significant level
of apparent endo-exo synergism with H. grisea and T. reesei endoglucanases. H.
grisea has at least two different types of major exoglucanase components and
shows strong cellulolytic activity through synergism with cellulase components
including EXO1 and CBH1.
PMID- 9756617
TI - Alpha 1,6-linked fucose affects the expression and stability of polysialic acid
carrying glycoproteins in Chinese hamster ovary cells.
AB - To determine the effect of alpha1,6-linked fucose modification of N-glycans on
the expression of polysialic acids (PSAs), the expression of PSAs in a fucose
lacking mutant of Chinese hamster ovary (CHO) cells, Lec13, was compared with
that in CHO K1 cells. PSA synthase activity in these cells and the antennary
structures of N-glycans associated with the neural adhesion molecule (NCAM),
which is a major PSA-carrying glycoprotein, did not differ between the two types
of cells. Metabolic labeling of cells with [3H]glucosamine for 48 h followed by
immunoprecipitation with anti-PSA monoclonal antibodies revealed that the amount
of labeled PSA-carrying glycoproteins obtained from Lec13 cells was 10-times less
than that from K1 cells, although the incorporation of [3H]glucosamine into total
extracts and NCAM was almost the same. In contrast, when cells were pulse labeled
with [35S]methionine followed by a 1 h chase, there was not such a great
difference in PSA-carrying protein synthesis between K1 and Lec13 cells. However,
during a prolonged chase period, PSA-carrying proteins rapidly decreased in Lec13
cells, whereas those in K1 cells did not change. The degradation of PSA-carrying
glycoproteins in Lec13 cells was partly prevented when the cells were grown in
fucose-containing medium. Therefore, fucose modification of core N-glycans may
affect the efficient expression of PSAs through the intracellular stability of
PSA-carrying glycoproteins.
PMID- 9756619
TI - Expression and characterization of a very low density lipoprotein receptor
variant lacking the O-linked sugar region generated by alternative splicing.
AB - The very low density lipoprotein receptor (VLDLR) gene contains an exon encoding
a region of clustered serine and threonine residues immediately outside the
membrane-spanning sequence, and this region has been proposed to be the site of
clustered O-linked carbohydrate chains. Two forms of VLDLR transcripts, with and
without the O-linked sugar region, are generated through alternative splicing.
Reverse transcription polymerase chain reaction with RNAs from various rabbit
tissues revealed that the VLDLR transcript with the O-linked sugar region (type-1
VLDLR) is the major transcript in heart and muscle, while the VLDLR transcript
without the O-linked sugar region (type-2 VLDLR) predominates in non-muscle
tissues, including cerebrum, cerebellum, kidney, spleen, adrenal gland, testis,
ovary, and uterus. Hamster fibroblasts expressing type-2 VLDLR bound with
relatively low affinity to beta-migrating very low density lipoprotein compared
with type-1 VLDLR-transfected cells. In contrast, the internalization,
dissociation, and degradation of the ligand were not significantly impaired in
either type of VLDLR-transfected cell. The receptor proteins in type-2 VLDLR
transfected cells underwent rapid degradation and accumulated in the culture
medium, while those in type-1 VLDLR-transfected cells were stable and resistant
to proteolytic cleavage. Analysis of the O-linked sugars of both types of
transfected cells suggested that the O-linked sugar region is the major site for
O-glycosylation.
PMID- 9756618
TI - Microtubule-stimulated phosphorylation of tau at Ser202 and Thr205 by cdk5
decreases its microtubule nucleation activity.
AB - Phosphorylation of tau, a heat-stable neuron-specific microtubule-associated
protein, by cdk5 was stimulated in the presence of microtubules (MTs). This
stimulation was due to an increased phosphorylation rate and there was no
increase in total amount of phosphorylation. Two-dimensional phosphopeptide map
analysis showed that MTs stimulated phosphorylation of a specific peptide. Using
Western blotting with antibodies that the recognized phosphorylation-dependent
epitopes within tau, the phosphorylation sites stimulated by the presence of MTs
were found to be Ser202 and Thr205 (numbered according to the human tau isoform
containing 441 residues). MT-dependent phosphorylation at Thr205 was observed in
situ in rat cerebrum primary cultured neurons. Stimulated phosphorylation at
Ser202 and Thr205 decreased the MT-nucleation activity of tau, which is in
contrast to MT-independent phosphorylation at Ser235 and Ser404.
PMID- 9756620
TI - Deletion analysis of protein kinase Calpha reveals a novel regulatory segment.
AB - Using a combined pharmacological and genetic approach, we have identified aa 260
280 in the C2 region as a critical factor in the catalytic function of protein
kinase Calpha (PKCalpha). Progressive truncations from the N-terminus as well as
selected internal deletion mutants were expressed in Saccharomyces cerevisiae and
tested for altered sensitivity to dequalinium, a PKC inhibitor whose target site
was previously mapped to the catalytic domain. PKC mutants representing
truncations of up to 158 amino acid residues (aa) from the N-terminus (ND84 and
ND158) displayed 60-63% inhibition of kinase activity by 50 microM dequalinium,
somewhat more sensitive than the wild-type PKCalpha enzyme (45% inhibition).
Mutant ND262, lacking N-terminal aa 1-262, was inhibited by almost 72% with 50
microM dequalinium, but mutant ND278, which lacked an additional 16 aa, was
inhibited by only 9% of total activity. This result suggests that a C-terminal
segment of the C2 region (aa 263-278) influences inhibition by dequalinium at low
micromolar concentrations. An internal deletion mutant (D260-280) which retains
the entire primary structure of PKCalpha except for aa 260-280, was similarly
inhibited by only 4% with 50 microM dequalinium. In the absence of dequalinium
and despite the presence of a nearly complete regulatory domain, this mutant
exhibited constitutive activity (both in vitro and in a phenotypic assay with S.
cerevisiae) that could not be further stimulated even by the potent activator
TPA. Taken together, our findings suggest that, in the native structure of
PKCalpha, the segment described by aa 260-280 regulates PKCalpha activity and
influences the sensitivity of PKCalpha to dequalinium.
PMID- 9756621
TI - Identification of arg-30 as the essential residue for the enzymatic activity of
Taiwan cobra phospholipase A2.
AB - Taiwan cobra (Naja naja atra) phospholipase A2 (PLA2) was inactivated by arginine
specific reagents, phenylglyoxal and 1, 2-cyclohexanedione. Kinetic analyses of
the modification reaction revealed that the inactivation of PLA2 followed pseudo
first-order kinetics and the loss of activity was correlated with the
incorporation of one molecule of modification reagent per PLA2 molecule. This was
confirmed by the results of amino acid composition determination, that showed
that a marked decrease in enzymatic activity was associated with the modification
of one arginine residue. Tryptic cleavage of the modified protein and
microsequencing revealed that Arg-30 was the functionally essential residue. The
incorporation of a modifier into the PLA2 did not significantly affect the
secondary structure of the enzyme, as revealed by the CD spectrum, and Ca2+
binding of the modified PLA2 was unaffected. Nevertheless, the nonpolarity of the
active site of PLA2 markedly decreased with the arginine modification, as
evidenced by the decreases in the enhancement of Trp and 8-anilinonaphthalene
sulfonate fluorescence. These results, together with those of X-ray
crystallographic analysis of N. naja atra PLA2 [Scott et al. (1990) Science 250,
1541-1546], demonstrate that Arg-30 is one of the residues involved in the
interfacial binding of a PLA2 molecule with its substrate.
PMID- 9756622
TI - Topological mutation of Escherichia coli dihydrofolate reductase.
AB - Proteins appear to contain structural elements which determine the folded
structure. If such elements are present, the order of structural elements in the
primary structure, i.e. the chain topology, can be disregarded for building of
the folded tertiary structure, when they are properly connected to each other by
proper linkers. To experimentally examine this, "topological" mutants (designated
as GHF33 and GHF34) of Escherichia coli dihydrofolate reductase (DHFR) were
designed and constructed by switching two amino acid sequence parts containing
the betaF strand and betaG-betaH strands in the primary sequence. In this way,
the chain topology of wild-type DHFR, betaA-->alphaB-->betaB-->alphaC-->betaC-->
betaD-->alphaE-->betaE-->al phaF-->betaF-->betaG-->betaH, was changed to betaA-
>alphaB-->betaB-->alphaC-->betaC--> betaD-->alphaE-->betaE-->al phaF-->betaG-
>betaH-->betaF. Such topological mutant proteins were stably expressed and
accumulated in E. coli cells, and highly purified. Molecular mass measurements of
the purified proteins and their proteolytic fragments confirmed that GHF33 and
GHF34 had the designed sequence. In terms of kcat, the GHF33 and GHF34 proteins
showed about 10 and 20% of the DHFR activity of the wild-type with Km values of
3.3 microM (GHF33) and 2.1 microM (GHF34), respectively. The topological mutants
showed a cooperative two-state transition in urea-induced unfolding experiments
with DeltaGH2O values of 4.0 and 4.8 kcal/mol. Whereas, the Km and DeltaGH2O
values for wild-type DHFR were 0.9 microM and 6.1 kcal/mol, respectively. The
significance of the topological mutations was discussed with respect to protein
folding and protein evolution.
PMID- 9756623
TI - Pyrrolidone carboxyl peptidase from the hyperthermophilic Archaeon Pyrococcus
furiosus: cloning and overexpression in Escherichia coli of the gene, and its
application to protein sequence analysis.
AB - A gene for a pyrrolidone carboxyl peptidase (Pcp: EC 3.4.19.3, pyroglutamyl
peptidase), which removes amino-terminal pyroglutamyl residues from peptides and
proteins, has been cloned from the hyperthermophilic Archaeon Pyrococcus furiosus
using its cosmid protein library, sequenced, and expressed in Escherichia coli.
The DNA sequence encodes a protein containing 208 amino acid residues with
methionine at the N-terminus. Analysis of the recombinant protein expressed in E.
coli, including amino acid sequence analysis from the N-terminus by automated
Edman degradation and ionspray mass spectrometric analysis of the peptides
generated by enzymatic digestions with lysylendopeptidase and Staphylococcus
aureus V8 protease, showed its primary structure to be completely identical with
that deduced from its cDNA sequence. Comparison of the amino acid sequence of P.
furiosus Pcp (P.f.Pcp) with those of bacterial Pcps revealed that a high degree
of sequence identity (more than 40%) and conservation of the amino acid residues
comprising the catalytic triad, Cys142, His166, and Glu79. On the other hand, a
unique short stretch sequence (positions around 175-185) that is absent in
bacterial Pcps was found in P.f.Pcp. A similar stretch has also been reported
recently in the amino acid sequence of Pcp from the hyperthermophilic Archaeon
Thermococcus litoralis [Littlechild et al., in abstracts of the "International
Congress on Exthermophiles '98" p. 58 (1998)]. To elucidate their contribution to
the hyperthermostability of these enzymes, further structural studies are
required.
PMID- 9756624
TI - A novel low-density lipoprotein receptor-related protein with type II membrane
protein-like structure is abundant in heart.
AB - We report herein the identification of a novel member of the low-density
lipoprotein receptor (LDLR) family termed LDLR-related protein 4 (LRP4). Murine
LRP4 cDNA encodes a 1113-amino-acid type II membrane-like protein with eight
ligand-binding repeats in two clusters. Southern blot analysis of genomic DNA
from several different organisms suggests the presence of LRP4 homologues in
chicken lacking the gene encoding apolipoprotein E, which is recognized by the
ligand-binding repeats of LDLR. LRP4 transcripts were detected almost exclusively
in heart in mouse and humans. Despite the presence of the ligand-binding repeats,
COS cells transfected with LRP4 did not show surface-binding of beta-migrating
very-low-density lipoprotein, suggesting that LRP4 plays a role in a pathway
other than lipoprotein metabolism.
PMID- 9756625
TI - Intersubunit structure within heterodimers of medium-chain prenyl diphosphate
synthases. Formation of a hybrid-type heptaprenyl diphosphate synthase.
AB - Among prenyltransferases that catalyze the sequential condensation of isopentenyl
diphosphate with allylic diphosphate to produce prenyl diphosphates with various
chain lengths and stereochemistries, medium-chain prenyl diphosphate synthases
are exceptional in that they comprise two dissociable heteromeric protein
components. These components exist without binding with each other under
physiological conditions, and neither of them has any prenyltransferase activity
by itself. In order to elucidate the precise molecular mechanism underlying
expression of the catalytic function by such a unique two-component system, we
examined the possibility of forming a hybrid between two of the components of
three different medium-chain prenyl diphosphate synthases, components I and II of
heptaprenyl diphosphate synthase from Bacillus subtilis, components I' and II' of
heptaprenyl diphosphate synthase from Bacillus stearothermophilus, and components
A and B of hexaprenyl diphosphate synthase from Micrococcus luteus B-P 26. As a
result, only the hybrid-type combination of component I and component II' gave
distinct prenyltransferase activity. The hybrid-type enzyme catalyzed the
synthesis of heptaprenyl diphosphate and showed moderate heat stability, which
lay between those of the natural enzymes from B. subtilis and B.
stearothermophilus. There is no possibility of forming a hybrid between the
heptaprenyl and hexaprenyl diphosphate synthases.
PMID- 9756626
TI - Phospholipid translocation from the outer to the inner leaflet of synaptic
vesicle membranes isolated from the electric organ of Japanese electric ray Narke
japonica.
AB - The phospholipid translocation from the outer to the inner leaflet of synaptic
vesicles isolated from the electric organ of the Japanese electric ray, Narke
japonica, was measured using fluorescent phospholipid probes. Phosphatidylcholine
(PC), phosphatidylethanolamine (PE), or phosphatidylserine (PS) with a
fluorescent NBD-labeled short acyl chain at the sn-2 position was mixed with
purified synaptic vesicles and the probe in the outer leaflet of the membranes
was reduced with dithionite to quench the fluorescence from time to time. The
percentage of fluorescence remaining after the dithionite treatment served as an
index for the phospholipid translocation. The results obtained indicated that
about 30, 13, and 9% of NBD-PE, NBD-PS, and NBD-PC, respectively, were
translocated from the outer to the inner leaflet in 3 h. Thus, the translocation
activity in synaptic vesicle membranes was much higher for PE than for PS, in
contrast to the previous results obtained with plasma membranes, including
synaptosomal membranes. The percentages of the phospholipid in the inner leaflet
at equilibrium were estimated to be 41, 31, and 14% for PE, PS, and PC,
respectively. The translocation was inhibited by pretreatment with an SH reagent,
iodoacetamide, indicating the involvement of a proteinaceous translocator. These
data may provide a biochemical basis for elucidating the mechanisms of membrane
fusion and exocytosis at nerve endings.
PMID- 9756628
TI - Effect of long-term ammonia starvation on the oxidation of ammonia and
hydroxylamine by Nitrosomonas europaea.
AB - Axenic cultures of the ammonia-oxidizing bacterium Nitrosomonas europaea were
starved of ammonia (energy source) for up to 342 d. During this time the bacteria
retained the ability to respond instantly to ammonia (1 mM) or hydroxylamine (0.1
mM) amendment by oxidizing it to nitrite without initial protein synthesis. In
vivo, the ability to oxidize amended ammonia stayed almost constant during the
starvation period, but a drop in the hydroxylamine oxidation rate (to 33%) was
observed after 4 wk of starvation when exogenous hydroxylamine was supplied as
sole energy source. In contrast, it has been shown that the level and in vitro
activity of hydroxylamine oxidoreductase were not significantly affected during
the starvation period. Only minor changes were detected between the protein
patterns on one-dimensional SDS-PAGE of growing and starved cells. Thus, it is
concluded that the activities of the energy-generating enzymes in N. europaea
were not affected during long-term ammonia starvation.
PMID- 9756627
TI - An endogenous target protease, SAM-P26, of Streptomyces protease inhibitor (SSI):
primary structure, enzymatic characterization, and its interaction with SSI.
AB - We have been focusing on the potent involvement of the molecular interaction
between a protease and a protease inhibitor in the physiological or morphological
regulation of Streptomyces cells producing them [Taguchi et al. (1995) J.
Bacteriol. 177, 6638-6643; Suzuki et al. (1997) J. Bacteriol. 179, 430-438]. In
this study, an extracellular protease, termed SAM-P26, was isolated as a target
of endogenous protease inhibitor (SSI) from the culture medium of an SSI non
producing mutant strain derived from Streptomyces albogriseolus S-3253. Complete
amino acid sequence determination revealed that SAM-P26 is identical to a protein
encoded by the SAM-P20D gene, which was previously found to be located downstream
of the gene for SAM-P20, another target protease of SSI. Based on the sequence
homology, SAM-P26 was categorized as a member of the chymotrypsin family like SAM
P20. Sequence similarity between SAM-P26 and SAM-P20 was immunologically
demonstrated by Western blot analysis using anti-SAM-P20 antiserum. The molecular
mass (26 kDa) of SAM-P26 estimated by sodium dodecyl sulfate-polyacrylamide gel
electrophoresis was much higher than that calculated from the amino acid sequence
of SAM-P26 (18,376.8 Da) and that of the S-pyridylethylated form (18,808.4 Da) of
SAM-P26 determined by Matrix-assisted Laser Desorption/Ionization-Time of
Flight/Mass Spectrometry. Analytical gel-filtration analysis revealed that SAM
P26 exists as a monomer (18.8 kDa) in the native state. The results as to
substrate specificity and inhibitor sensitivity indicated SAM-P26 exhibits
chymotrypsin-like activity. For the proteolytic activity, the optimal pH was 10.5
and the optimal temperature was 60 degreesC. The complex formation of SAM-P26
with SSI was confirmed by native-PAGE analysis.
PMID- 9756629
TI - Activities of mutant Sar1 proteins in guanine nucleotide binding, GTP hydrolysis,
and cell-free transport from the endoplasmic reticulum to the Golgi apparatus.
AB - Sar1p belongs to a unique subfamily of the small GTPase superfamily and is
essential for the formation of vesicles that transport proteins from the
endoplasmic reticulum to the Golgi apparatus. We have obtained mutants of the
yeast SAR1 gene, which show several different phenotypes in cell growth and
protein transport [Nakano, A. , Otsuka, H., Yamagishi, M., Yamamoto, E., Kimura,
K., Nishikawa, S., and Oka, T. (1994) J. Biochem. 116, 243-247; Yamanushi, T.,
Hirata, A., Oka, T., and Nakano, A. (1996) ibid. 120, 452-458]. In this study, we
have purified five mutant Sar1 proteins using an Escherichia coli expression
system and characterized their biochemical properties in detail. Three of them
prefer GDP binding to GTP binding and are thus regarded as GDP-form mutants, and
one is insensitive to the GTPase-activating protein and is almost fixed in the
GTP-bound state. The GDP mutants are defective in vesicle formation in vitro,
whereas the GTP mutant can drive vesicle formation but not the overall transport
to the Golgi. These mutants will be useful for further understanding of the
regulation of the GTPase cycle of Sar1p.
PMID- 9756630
TI - Characterization of the initial steps of precursor import into rat liver
mitoplasts.
AB - Mitochondria have two independent protein-import machineries, one in the outer
membrane (the Tom system) and the other in the inner membrane (the Tim system).
Here, we have characterized the initial steps of precursor import into rat liver
mitoplasts. The import reaction was separated into two stages, consisting of
precursor binding to the mitoplasts at 0-10 degreesC, and a subsequent chase
reaction at 30 degreesC. This assay revealed four distinct precursor-import
steps: DeltaPsi-dependent initial binding of the precursor, precursor transfer to
the Tim23-Tim17 stage, DeltaPsi-dependent translocation of the presequence across
the inner membrane, and the complete translocation of the mature portion of the
precursor. Antibodies against the intermembrane space domain of Tim23 inhibited
neither the precursor binding nor the subsequent translocation of the presequence
across the inner membrane. In contrast, the antibodies inhibited the complete
translocation of the mature domain of the precursor across the inner membrane.
Immunoprecipitation with anti-Tim23 IgGs revealed that the precursor-Tim23
complex increased with time and temperature after the initial targeting of the
precursor to the mitoplasts. These results suggest that the precursor is first
targeted to the inner membrane component DeltaPsi-dependently, then transferred
to the Tim system consisting of Tim23-Tim17, and finally imported into the
matrix.
PMID- 9756631
TI - Protection of mammalian cells from the toxicity of bleomycin by expression of a
bleomycin-binding protein gene from Streptomyces verticillus.
AB - A gene, blmA, encodes a bleomycin (Bm)-binding protein, designated BLMA, from Bm
producing Streptomyces verticillus and confers resistance to Bm in Streptomyces
and Escherichia coli cells. In the present study, by transfection of the gene
into COS-1 cells with a plasmid designated pEF-BOS/blmA, which contains a strong
promoter from the human polypeptide chain elongation factor 1alpha, we
transiently overproduced BLMA at a high level of approximately 4% of the whole
cell protein. Although NIH/3T3 cells transfected with pEF-BOS/blmA, designated
NIH/3T3-BR cells, stably expressed BLMA, its expression level was about 0.1% of
the total protein. Using an anti-BLMA monoclonal antibody reported previously
[Sugiyama et al. (1995) FEBS Lett. 362, 80-84], we revealed that BLMA is
localized in the nucleus of pEF-BOS/blmA-transfected COS-1 and NIH/3T3-BR cells.
Semi-permeabilized nuclear transport experiments showed that BLMA penetrates the
nuclear envelope by energy- and transporter-independent passive diffusion,
suggesting that the karyophilic nature of BLMA may be due to the acidic nature of
the protein. NIH/3T3-BR cells were 130-fold more resistant to Bm than the host
cells. NIH/3T3 cells exhibited a swollen nuclear envelope and a malformed spindle
body and overexpressed at least 4 kinds of stress proteins including calreticulin
and mitochondrial matrix protein P1 when exposed to 25 microg/ml of Bm, whereas
NIH/3T3-BR cells grew without morphological alteration and expressed no stress
proteins under the same conditions. Furthermore, reverse transcription-polymerase
chain reaction and Northern blot analysis showed that the expression of
interleukin-6, an inflammatory cytokine, is activated by addition of Bm in
NIH/3T3 cells, but not in the NIH/3T3-BR cells. These results suggest that BLMA
contributes to protection of mammalian cells from the inflammatory effect of Bm.
PMID- 9756632
TI - Single-step purification and characterization of MBP (maltose binding protein)
DnaJ fusion protein and its utilization for structure-function analysis.
AB - DnaJ is a molecular chaperone, which contains a zinc finger-like motif and
cooperates with DnaK to mediate the folding of newly synthesized and denatured
proteins. DnaJ was overproduced and purified using the maltose binding protein
(MBP) fusion vector. The fusion protein (MBP-DnaJ) was expressed in a soluble
form in Escherichia coli and purified to homogeneity using amylose resin in a
single step. The UV-visible absorption spectrum of MBP-DnaJ showed peaks at 355
and 475 nm. Moreover, these absorption peaks disappeared upon treatment with
ethylenediaminetetraacetic acid (EDTA) or p-hydroxymercuriphenylsulfonic acid
(PMPS). Inductively coupled plasma (ICP) spectrometry demonstrated that MBP-DnaJ
contains Fe ions as well as Zn ions. MBP-DnaJ mediated the replication of the
lambda phage in vivo, stimulated the ATPase activity of DnaK and prevented the
aggregation of denatured rhodanase, indicating that fusion of MBP to the N
terminal of DnaJ does not affect the functions of DnaJ. To study the roles of
bound metal ions, metal-free MBP-DnaJ, and MBP-DnaJ containing 2 Zn ions were
prepared. MBP-DnaJ containing Fe and Zn ions, and MBP-DnaJ containing 2 Zn ions
stimulated the ATPase activity of DnaK, prevented the aggregation of denatured
rhodanase and bound to DNA to similar extents. On the other hand, metal-free MBP
DnaJ showed much lower DNA-binding ability and lower ability to prevent rhodanese
aggregation. Therefore, the bound metal species do not affect the function of the
zinc finger-like motif of DnaJ, whereas removal of the metal ions from DnaJ
diminishes its binding ability as to DNA and denatured proteins.
PMID- 9756633
TI - Characterization and primary structure of a base non-specific and acid
ribonuclease from Dictyostelium discoideum.
AB - A base non-specific and acid RNase was isolated from cellular slime mold
(Dictyostelium discoideum) cells in a homogeneous state (about 2.4 kDa) by SDS
polyacrylamide gel electrophoresis. The RNase (RNase DdI) has a pH optimum of
5.0. The amino acid sequence of RNase DdI was determined by a combination of
protein chemistry, a search of Data base, Dicty cDB and further sequence analysis
of cDNA from the same bank. RNase DdI consists of 198 amino acid residues, and
about 13.3, 0.9, 1.2, 3.3, and 1.0 residues of mannose, xylose, glucose, GlcNAc,
and GalNAc, respectively. RNase DdI has two characteristic conserved segments of
the RNase T2 family, and thus belongs to the RNase T2 family. Considering the
fact that most of the RNase activity of D. discoideum is present in the lysosomal
fraction [Wiener and Ashworth (1970) Biochem. J. 118, 505-512], it was concluded
that the lysosomal RNase in D. discoideum is a member of the RNase T2 family. The
amino acid sequence of RNase DdI is highly homologous with that of Physarum
polycephalum RNase (RNase Phyb), and its amino acid sequence seems to be similar
to those of plant/animal type RNases, rather than fungal RNases. The location of
RNase DdI in the phylogenetic tree of the RNase T2 family was estimated.
PMID- 9756634
TI - Promotion of polypeptide folding by interactions with Asn-Glycans.
AB - We have recently revealed that the intramolecular Asn-glycans promote the
refolding of reductively denatured bovine pancreatic RNase B, and that
extramolecular Asn-glycans of both high-mannose and complex types also markedly
stimulate the oxidative refolding of RNase B and its nonglycosylated form, RNase
A [Yamaguchi, H. and Uchida, M. (1996) J. Biochem. 120, 474-477; Nishimura et al.
(1998) J. Biochem. 123, 516-520]. The present investigation was undertaken to see
whether this function of Asn-glycans is specific to the refolding of pancreatic
RNases; i.e., extramolecular Asn-glycans were examined for their effects on the
oxidative refolding of hen egg white lysozyme and bovine alpha-lactalbumin by
monitoring changes in activity, dynamic volume, intrinsic fluorescence, and
affinity for a fluorescent probe, 1-anilino-8-naphthalenesulfonate. Asn-glycans
of both high-mannose and complex types markedly stimulated the oxidative
refolding of these proteins, giving similar results to those previously obtained
with RNases, though differences attributable to the characteristics of individual
proteins were observed in the promotive effects. Thus it seems probable that Asn
glycans generally promote the proper folding of denatured polypeptides.
PMID- 9756635
TI - Desensitization of human muscarinic acetylcholine receptor m2 subtypes is caused
by their sequestration/internalization.
AB - Desensitization of human muscarinic acetylcholine receptor m2 subtypes (hm2
receptors) stably expressed in chinese hamster ovary cells was measured as
decreases in the carbamylcholine-stimulated [35S]GTPgammaS binding activity in
membrane preparations after pre-treatment of cells with carbamylcholine. The
extent of carbamylcholine-stimulated [35S]GTPgammaS binding activity was found to
decrease to 64% following pretreatment of cells with 10 microM carbamylcholine
for 30 min, and under the same conditions 51-59% of hm2 receptors were
sequestered/internalized as assessed by decreases in the [3H]N-methylscopolamine
binding activity on the cell surface. A similar reduction in the carbamylcholine
stimulated [35S]GTPgammaS binding activity was observed by pretreatment of cells
with 5 nM propylbenzylylcholine mustard, which irreversibly bound to and
inactivated 58% of the hm2 receptors. When the cells were pretreated with 10
microM carbamylcholine in the presence of 0.32 M sucrose, which is known to
inhibit clathrin-mediated endocytosis, no sequestration/internalization of hm2
receptors was observed, and the extent of carbamylcholine-stimulated
[35S]GTPgammaS binding activity did not change. These results indicate that
desensitization of hm2 receptors may be caused by reduction of receptor number on
the cell surface through sequestration/internalization rather than by loss of the
function of receptors.
PMID- 9756636
TI - Serum amine oxidase can specifically recognize and oxidize aminohexyl (AH) chains
on AH-Sepharose support: single-step affinity immobilization.
AB - Preparative affinity chromatography of bovine serum amine oxidase (SAO) on
aminohexyl (AH)-Sepharose was often associated with an unexpected irreversible
SAO retention on the support. This particular enzyme immobilization, occurring
without coupling reagents, was supposed to be due to a SAO ability to: (i)
recognize alkylamine groups of the support as macro-molecularized substrate; (ii)
catalyse their oxidation to the corresponding aldehydes, with release of NH3 and
H2O2; and (iii) be immobilized on the activated support by a coupling between the
nascent aldehyde groups and SAO free amine groups. This affinity immobilization
procedure, with the self-activation of the support, being mild, allows by simple
incubation for 24 h, the enzyme immobilization with the retention of 80% from
original specific activity of free SAO. Immobilized SAO on AH-Sepharose
microcolumns, viewed as a continuous flow-system reactor, was able to catalyse
benzylamine oxidation for several weeks.
PMID- 9756638
TI - Multinucleated giant cell formation induced by IFN-gamma/IL-3 is associated with
restriction of virulent Mycobacterium tuberculosis cell to cell invasion in human
monocyte monolayers.
AB - One of the hallmarks of an effective immune response against Mycobacterium
tuberculosis is the formation of granulomas containing multinucleated giant
cells. IFN-gamma and interleukin-3 (IL-3) promote Langhans-type multinucleated
giant cell formation and have been identified in T cell clones reacting to M.
tuberculosis antigens. The ability of human monocytes treated with IFN-gamma and
IL-3 to limit the spread of M. tuberculosis in an in vitro infection assay was
examined. Monocytes were incubated with control medium, IFN-gamma, TNF-alpha, and
calcitriol, a combination permissive to M. tuberculosis growth, or IFN-gamma and
IL-3 and infected with a low inoculum of M. tuberculosis (Erdman). IFN-gamma/IL-3
treatment reduced M. tuberculosis CFU relative to both untreated and IFN
gamma/TNF-alpha/calcitriol-treated monocytes. Specifically, CFU were reduced by
79% at 14 days in the IFN-gamma/IL-3 treatment group relative to the IFN
gamma/TNF-alpha/calcitriol treatment group, an effect that was not due to toxic
monocyte metabolites. M. tuberculosis growth restriction by IFN-gamma/IL-3
treated monocyte monolayers was associated with the development of Langhans-type
multinucleated giant cells. At the light microscope level, dense growth of M.
tuberculosis surrounded by a ring of nuclei localized to the center of individual
cells. The intracellular location of M. tuberculosis was confirmed by electron
microscopy. In contrast, monocyte monolayers treated with IFN-gamma/TNF
alpha/calcitriol consisted of a syncitium of cells containing monocyte
aggregates. Nonlocalized linear arrays of M. tuberculosis were observed to be
growing throughout such aggregates. These results suggest that physical
sequestration of M. tuberculosis by Langhans-type multinucleated giant cells may
limit cell to cell spread of this pathogen, thereby restricting growth.
PMID- 9756637
TI - Regulation of arachidonic acid release and prostaglandin E2 production in thymic
epithelial cells by ATPgammaS and transforming growth factor-alpha.
AB - The arachidonic acid metabolites produced by thymic epithelial cells play a
pivotal role in thymocyte development. We have discovered that ATP and TGF-alpha
regulate the arachidonic acid metabolism in TEA3A1 rat thymic epithelial cells by
activating phospholipase A2 enzymatic activity. Our present study demonstrates
that ATP and its nonhydrolyzable analog ATPgammaS stimulate both prostaglandin E2
production and Ca2+ influx in TEA3A1 cells. The stimulation of prostaglandin E2
production and Ca2+ influx by ATP is inhibited by pertussis toxin treatment,
indicating that ATP mediates its effect by binding to a G-protein-coupled
purinergic receptor. Treatment of cells with ATPgammaS and transforming growth
factor-alpha results in a synergistic activation of phospholipase A2 and
stimulation of prostaglandin E2 production. Results from experiments using an
inhibitor of receptor-mediated Ca2+ influx indicate that the synergistic
stimulation of prostaglandin E2 production by ATPgammaS and transforming growth
factor-alpha requires ATPgammaS-mediated Ca2+ influx. The inhibitor of tyrosine
kinase genistein also blocked both ATPgammaS- and ATPgammaS plus transforming
growth factor-alpha-mediated stimulation of prostaglandin E2 production,
indicating that the activation of phospholipase A2 may involve a protein tyrosine
phosphorylation step.
PMID- 9756639
TI - Control of endotoxin shock by the dried preparation of low virulent Streptococcus
pyogenes OK-432.
AB - Bacterial endotoxin, lipopolysaccharide (LPS), is a causative agent of Gram
negative septic shock. However, if preadministered at a low dose, LPS makes mice
resistant to subsequent endotoxin challenge, the phenomenon known as LPS
tolerance. Here we demonstrated that the pharmaceutical preparation of Gram
positive Streptococcus pyogenes, OK-432, also induced a state analogous to LPS
tolerance if administered 6-48 h prior to LPS challenge. The preadministration of
OK-432 increased the lethal dose of LPS threefold in BDF1 mice, and this was
accompanied by reduced gene expression of IL-6, IFN-gamma, inducible nitric oxide
synthase, and IL-10 in spleen and peritoneal cells. Serum concentrations of IL-6
and IFN-gamma were also suppressed by the preadministration of OK-432. In
contrast to the LPS tolerance, the levels of TNF-alpha mRNA were not suppressed
in OK-432-administered mice, and their peritoneal cells produced high levels of
TNF-alpha and soluble TNF receptor p75 in response to LPS in vitro. Peritoneal
cells from OK-432 but not LPS-administered mice were hyporesponsive to IFN-gamma
in terms of nitric oxide synthesis, and this hyporesponsiveness to IFN-gamma was
abrogated by anti-IL-10 antibodies. Likewise, peritoneal cells from both OK-432-
and LPS-administered mice were hyporesponsive to LPS, serum, TNF-alpha, IFN
gamma, and PMA in terms of IL-6 production. Anti-IL-10 antibodies increased IL-6
production eightfold in cells from OK-432-administered mice, but marginally in
cells from LPS-administered mice. Even in peritoneal cells from OK-432
administered mice, anti-IL-10 antibodies failed to fully restore IL-6 production.
Thus, the hyporesponsive state of peritoneal cells was mediated by both IL-10
dependent and -independent mechanisms. These results demonstrated that OK-432
controlled endotoxin shock by blocking the cytokine cascade from TNF-alpha.
PMID- 9756640
TI - Interleukin-12 is expressed by infiltrating macrophages and synovial lining cells
in rheumatoid arthritis and osteoarthritis.
AB - TH1 cytokines have recently been detected in rheumatoid arthritis (RA) and
osteoarthritis (OA). For this reason we studied the TH-1-promoting cytokine IL-12
in synovial membranes from patients with RA and OA. IL-12 transcripts and protein
were analyzed by reverse transcriptase-polymerase chain reaction (PCR) and
immunohistochemistry, respectively. In addition, IL-12 transcripts were
quantitated by competitive PCR. IL-12 transcripts (p40) were detected in 8 of 13
patients with RA and in 10 of 18 patients with OA. Their levels did not differ
significantly between RA and OA. IL-12 heterodimer protein was detected by
immunostaining using an anti-IL-12p70 mAb. Double labeling with anti-IL-12p70 and
anti-CD68 mAbs showed that synovial lining cells and monocytes/macrophages
expressed IL-12 p70 protein. The presence of IL-12 p70 protein in the synovial
membranes of patients with RA and OA suggests that IL-12 may play an important
immunoregulatory role in these diseases by perpetuating inflammation.
PMID- 9756641
TI - The wst gene regulates multiple forms of thymocyte apoptosis.
AB - Mice homozygous for the autosomal recessive mutation Wasted (wst/wst) display a
disease characterized by immunodeficiency, cerebellar dysfunction, and
sensitivity of their hematopoeitic cells to gamma radiation. Wasted mice die by
30 days of age. In this report, we show that the Wasted thymus shows evidence of
dramatically increased apoptosis in situ. Moreover, wst/wst thymocytes are more
sensitive to apoptosis induced by gamma radiation, heat shock, alpha-CD3
stimulation, and dexamethasone treatment in vitro. Thus, wst gene is a regulator
of thymocyte apoptosis both in vitro and in vivo. The elevated levels of
thymocyte apoptosis may be a major contributor to the lymphoid dysfunction and
ultimate death in wst/wst mice.
PMID- 9756642
TI - Acceleration of experimental autoimmune encephalomyelitis in interleukin-10
deficient mice: roles of interleukin-10 in disease progression and recovery.
AB - Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the
central nervous system (CNS) which is often used as an animal model for human
multiple sclerosis (MS). The disease is mediated by autoreactive lymphocytes
recognizing myelin self-antigens. The autoreactive lymphocytes elicit autoimmune
inflammation in the CNS and lead to demyelination and loss of neurological
functions. Although autoimmune encephalomyelitis can lead to irreversible nervous
tissue injury and demise of animals, EAE is often characterized by spontaneous
disease recovery or remission. It is not known how EAE progression is regulated,
nor is it clear how autoimmune inflammation in the CNS can resolve while the
myelin-specific lymphocytes and myelin self-antigens remain in the animals.
Cytokines, especially TH2-type cytokines, have long been suggested to play a role
in regulating EAE. However, experiments using recombinant cytokines or
neutralizing antibodies to cytokines have generated conflicting results. To
determine the roles of interleukin (IL)-4 and IL-10 in experimental autoimmune
encephalomyelitis, we have studied mice deficient in IL-4 or IL-10. We found that
IL-10- but not IL-4-deficient mice had accelerated EAE following immunization
with myelin oligodendrocyte glycoprotein (MOG). Importantly, spontaneous recovery
from EAE occurred in normal and IL-4-deficient mice, but not in mice deficient in
IL-10. Furthermore, we established that the acceleration of EAE in IL-10
deficient mice was associated with a decrease in IL-4 and an increase in IFN
gamma production in response to MOG antigen. These results strongly suggest that
IL-10 plays a crucial role in the progression and recovery of autoimmune
encephalomyelitis.
PMID- 9756643
TI - Induction of T cell anergy by high concentrations of immunodominant native
peptide is accompanied by IL-10 production and a block in JNK activity.
AB - The ability to induce anergy in antigen-specific T cells has potential
therapeutic value for altering pathologic immune responses. This study was
undertaken to further analyze changes in cytokine production and intracellular
signaling during anergy induction using high concentrations of native peptide
ligand of tetanus toxoid (TT)- and myelin basic protein (MBP)-specific human T
cell lines. The TT-selected T cell line could be rendered unresponsive to its
dominant epitope in a dose-dependent manner (IC50 = 0.03 microg/ml). The TT
selected line, as well as three T cell clones established from this line,
continued to produce IFN-gamma and significantly increased IL-4 and IL-10
production when anergy was induced with high concentrations of the immunodominant
epitope. JNK enzymatic activity was blocked in anergized T cells. The MBP
selected line could likewise be rendered unresponsive by incubation with
supraoptimal concentrations of immunodominant peptide and anergy induction was
accompanied by IL-10 release. Both T cell lines could be anergized by the
autopresentation of native peptide since anergy was induced in cultures lacking
fresh antigen-presenting cells. This study shows that the mitogen-activated
protein kinase cascade is blocked when anergy is induced to high concentrations
of soluble peptide.
PMID- 9756644
TI - Membrane IgM-stimulated human B lymphocytes succumb to activation-related
apoptosis at a G1-->S transition: influence of ligand affinity and valency.
AB - Culture of human B lymphocytes with polyclonally activating surrogates for type
II T-cell-independent antigen, i.e., anti-IgM mAb and anti-IgM:dextran, resulted
in both membrane IgM (mIgM)-triggered S/G2/M entry and apoptosis. Although high
ligand valency could compensate for low affinity, and high affinity could
compensate for low valency, in achieving mIgM-triggered apoptosis, the phenomenon
was most pronounced when the soluble "antigen" had both high binding site
affinity and valency. Most of the mIgM-triggered apoptosis may represent B cells
which progress into G1 but fail to receive a sufficient level of continuous mIgM
mediated signaling during G1 for passage through a G1 --> S phase restriction
point(s). This was supported by the findings that (a) a lesser proportion of mIg
triggered cells enter S phase than G1; (b) maximal mIgM-triggered apoptosis was
noted at 48-72 h of culture and surrounding activated cell clusters; (c) mIgM
triggered apoptosis was not inhibited by pharmacologic blockers of S phase; and
(d) a high proportion of viable mIgM-triggered B cell blasts in G1 succumb to
apoptosis rather than enter S phase, if high-affinity multivalent ligand is
washed from the cultures. In addition to quantitative aspects of initial receptor
engagement, the potential for a protracted period of recurrent mIgM signaling
events may influence whether apoptosis or cell cycle progression is the
functional outcome of B cell encounter with a multivalent antigen.
PMID- 9756648
TI - pH- and Thermo-sensitive Hydrogel Nanoparticles.
AB - pH- and temperature-sensitive hydrogel nanoparticles of copolymers of
vinylpyrrolidone (VP) and acrylic acid (AA) cross-linked with NN' methylene bis
acrylamide (MBA) of sizes up to 50 nm diameter loaded with marker compound FITC
dextran (mol wt. 19.3 kD) were prepared in the aqueous core of reverse micellar
droplets and were dispersed in aqueous buffer. These particles have high
entrapment efficiency, and the lyophilized powder can be redissolved in buffer
without any significant agglomeration. The release of FITC-dextran from these
particles was found to be pH- and temperature-dependent. The release was slow in
acid solution, but it increased considerably as the pH of the medium was
increased. The release rate was also increased with the increase of temperature.
Copyright 1998 Academic Press.
PMID- 9756645
TI - Decreased protein levels of the c-Cbl protooncogene in murine AIDS.
AB - Murine acquired immunodeficiency syndrome (MAIDS) can be viewed as a
lymphoproliferative disease which involves B cells as well as T cells from spleen
and lymph nodes while thymus and Peyer's patches do not participate in the
process. The 120-kDa protooncogene product c-Cbl was initially cloned from the
murine Cas NS-1 B cell lymphoma. It is a main target of immunoreceptor (TCR and
BCR)-mediated protein tyrosine kinase activity. Moreover, recent data suggest
that c-Cbl might play a crucial role in the regulation of cell proliferation
through regulation of GTP-binding proteins. Therefore, the involvement of c-Cbl
was evaluated in the lymphoproliferative disease induced by the MAIDS virus. The
expression of the c-Cbl protein was dramatically reduced in the lymph node of
infected mice while it remained normal in the thymus. In contrast, the expression
of actin, TCR-zeta chain, ZAP-70, and p59(fyn) remained similar in controls and
infected mice. Identical results were obtained with sorted B cells and T cells.
Surprisingly, a B cell lymphoma line derived from late stage MAIDS mice displayed
a normal level of c-Cbl.
PMID- 9756649
TI - Thermodynamics of Cationic Surfactant Sorption onto Natural Clinoptilolite.
AB - Sorption enthalpies of hexadecyltrimethylammonium bromide (HDTMA) as monomers and
micelles and tetraethylammonium bromide (TEA) were used with surfactant,
counterion, and co-ion sorption isotherms to infer the conformation, sorption
mechanism, and relative stability of the sorbed surfactants on natural
clinoptilolite. The average value of the sorption enthalpy was -10.38 kJ/mol for
monomers, -11.98 kJ/mol for micelles, and +3.03 kJ/mol for TEA. Sorption of
monomers produced a lower sorption plateau than equivalent micelle sorption
(maxima 145 mmol/kg, 225 mmol/kg). Analysis of the sorption data demonstrated a
change in the sorption mechanism at the external cation exchange capacity (ECEC)
of clinoptilolite. Sorption data from below and above the ECEC were fit to a
simple polynomial model and the Gibbs free energy of sorption (DeltaG0m) and
sorption entropies were calculated. Resultant values of DeltaG0m were -9.27 and
14.38 kJ/mol for HDTMA monomers and micelles, respectively, for sorption below
the ECEC, and -16.11 and -23.10 kJ/mol, respectively, for sorption above the
ECEC. The value for TEA was -1.04 kJ/mol, indicating weaker sorption than for
HDTMA. Monomer sorption to clinoptilolite exceeded the ECEC, even when the
solution concentration was below the critical micelle concentration. Hydrophobic
(tail-tail) components of DeltaG0m were the driving force for sorption of HDTMA,
both below and above the ECEC. A significant kinetic effect was observed in the
sorption isotherms with a period of rapid sorption followed by slow equilibration
requiring 7 days to achieve steady state for HDTMA; TEA equilibration occurred
within 24 h. Copyright 1998 Academic Press.
PMID- 9756650
TI - Dispersion Stability and Photo-activity of Rutile (TiO2) Powders.
AB - The dispersion stability and photo-activity of rutile (TiO2) powders are
reported. Factors influencing these properties, such as the pH values of the
solutions used to treat the surfaces and the concentration of inorganic solids
such as SiO2 and Al2O3 deposited onto the surfaces, are investigated. Si only on
the surface of TiO2 gave rise to a poor coating efficiency, but a mixture of Al
and Si improved it considerably. SiO2 precipitates onto the surface of rutile at
a higher pH (9.04) than Al2O3 (7.9), and it can be assumed that, in cases where
both are precipitated from one mixture, a layer of silica is first formed.
Temperature seems to have a negligible effect on the coating efficiency of Al2O3
if Al2(SO4)3 is used as a surface agent, but when NaAlO2 is used a non-linear
correlation exists between temperature and coating efficiency, which is higher at
291 K than at higher temperatures. TiO2 surfaces treated with SiO2 show a greater
dispersion stability than those treated with Al2O3. In the cases of SiO2/Al2O3
mixtures that were deposited onto the surfaces, the dispersion stability
increased when the Si/Al ratios exceeded 0.6, although the absolute mass of Al2O3
deposited also affects this stability. The influence of various organic reagents
on the dispersion stability is reported. The photo-activity of the samples was
determined by means of the degradation of methylene blue on the surface.
Copyright 1998 Academic Press.
PMID- 9756651
TI - New Methods for Studying Foams: Foaminess and Foam Stability.
AB - New methods for studying the foaminess (the surface foam stability) and the foam
stability (the internal structural foam stability) have been elaborated. The
experimental technique and results are presented. Copyright 1998 Academic Press.
PMID- 9756652
TI - Low-Frequency Dielectric Response of Polystyrene Latex Dispersions.
AB - The low-frequency permittivity and the conductivity increments of a well
characterized polystyrene sulfate latex with constant surface charge density were
measured in KCl electrolyte solutions. The ionic strength was varied in the range
0.4-6 mM. The data could be explained with one absolute surface-conductivity
parameter over the complete concentration range. The titratable surface charge
density correlates well with the surface conductivity, the ions in the double
layer having the bulk mobility. The results are in good agreement with static
conductivities of plugs composed of the same particles obtained in a previous
study (1). The electrokinetic charge obtained from streaming potentials (1) in
that study is significantly lower, confirming the presence of conduction behind
the shear plane. In order to interpret the conductivity data, simple analytical
expressions have been derived for the frequency-dependent complex conductivity of
a dilute dispersion of spherical particles with relatively thin double layers
(kappaa >>1, where a is the particle radius and kappa-1 the Debye screening
length). The expressions are restricted to binary suspending electrolytes.
However, no restrictions on the ion mobilities and ion valencies are made. Our
results agree well with the numerical results of the dielectric model of
Mangelsdorf and White (2, 3) and reduce to O'Brien's static conductivity results
(4) in the limit of low frequencies. Copyright 1998 Academic Press.
PMID- 9756653
TI - A New Methodology for Studying Protein Adsorption at Oil-Water Interfaces.
AB - A new methodology has been developed for studying the adsorption behavior of
proteins at oil-water interfaces. This technique employs the radiotracer method
for monitoring adsorption of 14C-labeled proteins at the oil-water interface. The
uniqueness of the new method lies in the formation of a 1000 A thick triglyceride
oil film on the water surface. beta-casein was used to generate a standard curve
for relating interfacial radioactivity (uCi/m2) to cpm at the oil-water
interface. Adsorption isotherm of beta-casein was determined in the bulk protein
concentration range 1.5 x 10(-5)-3.8 x 10(-3)% by weight of solution. The
saturated monolayer coverage was found to be about 7.3 mg/m2. This value was
quite different from other values reported in the literature. Adsorption studies
with another protein, lysozyme, at the oil-water interface also revealed a high
surface concentration of 3.0 mg/m2. The most significant difference between the
adsorption of beta-casein at the oil-water and air-water interfaces was the lack
of an induction period for the development of interfacial pressure in the former.
This difference may be attributed to the attractive dispersion interaction
between protein molecules and the oil phase. Copyright 1998 Academic Press.
PMID- 9756654
TI - The Instability of Silica Sol in Concentrated Solutions of Triton X100.
AB - An excess of nonionic surfactant, Triton X100, in the continuous phase of silica
sol has strong consequences on the stability of silica dispersions. Beyond full
coverage, the surfactant may give rise to the formation of either fractal or
dense aggregates. The structure of aggregates has been studied through SAXS. It
has been demonstrated that hydration of the components is an essential ingredient
which influences the interparticle interactions. Some comparisons with current
theoretical models developed for depletion flocculation are made. Copyright 1998
Academic Press.
PMID- 9756655
TI - Surfactant Effect on the Stability and Electrorheological Properties of
Polyaniline Particle Suspension.
AB - In this paper, the colloidal stability and electrorheological responses of semi
conductive polyaniline particles dispersed in a mineral oil were investigated
experimentally. The polyaniline was synthesized by polymerization of aniline
monomer. The surfactants used for the colloidal stability were commercially
available nonionic Span20, Span80, and Span85, which are distinctly different in
their molecular structures. Dynamic yield stress of polyaniline suspension, which
possessed the quadratic dependence on electric field strength at low electric
field, exhibited the linear dependence at high electric field. In addition, the
conductivity of polyaniline particles influenced the electrorheological response
and there existed the optimal conductivity for the maximum yield stress. In the
presence of nonionic surfactants used here, the yield stress of polyaniline
exhibited a local maximum at a certain surfactant concentration. The existence of
optimal surfactant concentration was confirmed by the surfactant adsorption
isotherm. We hypothesized that below the optimal threshold concentration, the
electrorheological activity was enhanced by the increased interfacial
polarization induced by the adsorbed surfactant molecules. Above the threshold
concentration, however, the electrorheological activity was degraded by the
conduction through the field-induced surfactant-rich bridge between adjacent
particles. This optimal concentration coincided with the saturation concentration
in the adsorption isotherm. The surfactants used in this study showed the
improved colloidal stability due mainly to the induced steric hindrance effect.
For the colloidal stability, Span80 was the most effective. However, considering
that ER activity comes mainly from relatively large particles of O(um), which are
mostly present in our system, Span85 was the best choice for a stabilizing
additive in the present ER suspension. In addition, our results showed that the
presence of the nonionic surfactants considered here did not cause any sensible
degradation at high temperatures. Copyright 1998 Academic Press.
PMID- 9756656
TI - Formation and Properties of Lamellar Phases in Systems of Cationic Surfactants
and Hydroxy-Naphthoate.
AB - We investigated the phase behavior and the phase transitions in aqueous solutions
of 100 mM cetyltrimethylammonium hydroxide (CTAOH) with 3-hydroxy-2-naphthoic
acid (HNC) and of 100 mM cetyltrimethylammonium bromide (CTAB) with sodium-3
hydroxy-2-naphthoate (SHNC). The naphthoate/surfactant ratio has been varied. As
previously observed by the groups of C. Manohar and J. Candau we observed for the
second system two viscoelastic gel-like regions, two liquid crystalline regions,
and a precipitate region. For the CTAOH/HNC system one finds with increasing
concentration of HNC a low viscous solution, a viscoelastic gel, and a
viscoelastic liquid crystalline Lalpha-phase. In both surfactant systems the
lamellar phase is formed around an equimolar ratio of cationic surfactant and
naphthoate. The lamellar phases have been examined by polarization microscopy and
freeze-fracture electron microscopy. The Lalpha-phase in the system CTAOH/HNC
consists of densely packed multilamellar vesicles while the lamellar phase in the
system CTAB/SHNC contains vesicles, as well as stacked bilayers and tubuli.
Corresponding to their different microstructures the lamellar phases in the
system, CTAOH/HNC and CTAB/SHNC have different rheological properties. The
vesicular phase is highly viscoelastic and has a yield stress value while the
bilayer phase has a much lower viscosity and no yield stress value. The
transition from the micellar to the vesicle phase occurs for CTAOH/HNC over a two
phase region, where micelles and vesicles coexist. In the case of CTAB/SHNC the
transition from the micellar to the lamellar phase occurs over a three-phase
region, where a surfactant-poor phase coexists with a lamellar and a coacervate
phase. In mixtures of CTAB and SHNC a thick precipitate is formed at an equimolar
ratio of CTAB and SHNC. This precipitate consists of condensed multilamellar
vesicles that contain little water and stick together, as the vesicles collapse
due to the shielding of the repulsive forces by NaBr from an unbinding to a
binding state. The precipitate can be retransformed to a swollen lamellar phase
by charging the vesicles with an excess of ionic surfactant, by adding
electrolyte in high concentrations, or by increasing the temperature. As
predicted by C. Manohar et al. the vesicle phases show a phase transition at a
critical temperature Tc of 46 degreesC. This transition was detected by us for
the first time by DSC and by conductivity measurements. It occurs within a narrow
temperature range of 2-3 degrees with an enthalpy change of 0.5 kJ/mol. The
transition is observed both in the swollen and in the precipitated vesicle phase.
It is well separated from the vesicle/rod transition at higher temperatures (>70
degreesC) and the liquid crystalline/crystalline transition at lower temperatures
(25-30 degreesC) that has a melting enthalpy of 55 kJ/mol. It is conceivable that
the observed transition at 46 degreesC is due to the melting of a two-dimensional
solid-like lattice of the HNC-counterions on the vesicle interface. Copyright
1998 Academic Press.
PMID- 9756657
TI - Modified van der Waals Equation for the Prediction of Multicomponent Isotherms.
AB - A modified two-dimensional van der Waals equation model was proposed for the
prediction of multicomponent gas-solid adsorption isotherms from corresponding
single-component adsorption equilibrium data. The model was used to predict
adsorption isotherms of CO-CO2 mixtures and CO2-N2 mixtures on Cu(I)-NaY zeolite.
Experimental adsorption equilibrium data of the two systems were compared with
results calculated from the model and three other models in the literature: the
ideal adsorbed solution model, the vacancy solution theory of adsorption using
the Flory-Huggins activity coefficient equation, and the two-dimensional van der
Waals equation. The results indicated that the modified van der Waals equation
predicted the experimental results better than the three other models for the two
systems studied, especially for the CO-CO2 system, which involved chemical
reaction during adsorption and exhibited azeotropic behavior. Copyright 1998
Academic Press.
PMID- 9756658
TI - Simulation of Particle Adsorption onto a Polymer-Coated Surface Using the
Dissipative Particle Dynamics Method.
AB - Dissipative particle dynamics (DPD) was originated as a tool for performing fluid
dynamics simulations of complex fluids and among other things has been used to
simulate dilute polymer solutions. This report describes a new application of the
technique-modeling the adsorption of colloidal particles onto a polymer-coated
surface. This type of simulation would be beyond the scope of molecular dynamics
but is effectively modeled with DPD. The preliminary results of these
investigations, presented here, show good agreement with what might be predicted
theoretically. They show that the colloidal particles would be less likely to
adsorb onto the surface as the size of the polymer relative to the particle is
increased, or similarly as the density of the polymers is increased. They also
show that particle adsorption is reduced when the polymer is well solvated. They
demonstrate how particles that have agglomerated with each other find it more
difficult to penetrate a polymer barrier because of their greater size. Further
investigation is required to understand the effects of temperature. Copyright
1998 Academic Press.
PMID- 9756659
TI - TM-AFM Threshold Analysis of Macromolecular Orientation: A Study of the
Orientation of IgG and IgE on Mica Surfaces.
AB - Adsorption and orientation properties of two different types of immunoglobulin
molecules on derivatized and native mica surfaces were investigated using TM-AFM.
The analyses included height measurements at two different pH values and a new
technique, presented here as threshold analysis, which displays the outer mantle
shape of an adsorbed protein. A major difference in preferential orientation is
observed upon comparing the adsorption of the two proteins onto the different
surfaces. The characteristics of both the adsorbed immunoglobulin and the surface
are important for any preferential orientation of the adsorbed protein. Copyright
1998 Academic Press.
PMID- 9756660
TI - Part I: Experimental.
AB - Perikinetic coagulation experiments are reported which were performed under 1g
and ug conditions during a flight in a sounding rocket, for dispersions of
polystyrene, quartz, and amorphous silica particles. Coagulation rates for
dispersions of polystyrene, quartz, and amorphous silica are found to increase
significantly under ug conditions compared to 1g conditions. Another set of
experiments was performed at 1g, 2g, 4g, and 7g, with different densities of the
continuous phase; also a mixture of two different polystyrene latices was used.
The most pronounced effect of gravity on coagulation rate is found for
dispersions with a small density difference, on going from 1g to 2g. In this
regime a significant decrease in coagulation rates is observed. For the latex
mixture at pronounced density differences, gravity-induced coagulation was
observed; however, the aggregates formed did not have a lasting contact. The rate
constant calculated under ug conditions approaches the theoretical value of von
Smoluchowski. By means of a video analysis of the perikinetic coagulation
process, the formation of doublets was studied. The "interaction time" for two
particles was found to be longer for the density-matched dispersion. Doublets of
particles are easily disrupted, and at 1g, free convection currents were observed
even at small temperature differences in the system. Copyright 1998 Academic
Press.
PMID- 9756661
TI - Part II: Theoretical Analysis.
AB - Three phenomena involved in the perikinetic coagulation process were studied with
regard to their ability to account for the influence of gravity on the
coagulation rate: (1) surface charge effects on the pressure in the gap between
two approaching particles, through the streaming potential generated by the
squeezing flow; (2) free convection induced by temperature changes in the
surroundings; (3) surface roughness and hydration force effects on the
interaction force between two particles. In a separate paper flow interactions
between two identical spheres are shown to be insufficient to explain the
influence of gravity on coagulation rate. Of these phenomena studied, a
combination of surface roughness and free convection can explain the influence of
gravity on coagulation. Copyright 1998 Academic Press.
PMID- 9756662
TI - Structure of the Aggregates During the Process of Aggregation and Breakup Under a
Shear Flow.
AB - A particle size analyzer together with a video camera has been used to
investigate the structure of the aggregates during the process of aggregation and
breakup of particles in a shear flow induced by means of a Couette-flow system.
Three different values for the shear rate have been used (25, 32, and 50 s-1).
The initial volume fraction of the particles was phi0 = 5.0 x 10(-5). Different
fractal dimensions (D3), D2, D1, and Dpf), the shape factor (xi2), and the aspect
ratio (AR) have been used to characterize the structure of the aggregates. During
the process of aggregation, no significant changes in the fractal dimensions,
shape factor, and aspect ratio were found. The high values obtained for D3 (D3 =
2.2) and D2 (D2) = 1.98) show us the high compactness of the flocs. Also, values
of the fractal dimension and shape factor have been found to not depend on the
shear rate. Copyright 1998 Academic Press.
PMID- 9756663
TI - Influence of Size on Electrokinetic Behavior of Phosphatidylserine and
Phosphatidylethanolamine Lipid Vesicles.
AB - The aim of this study was to examine the electrokinetic properties of liposomes
containing either phosphatidylethanolamine (PE) or phosphatidylserine (PS). Zeta
potential was determined by laser-Doppler microelectrophoresis. The presence of
PE enhanced the slight negative charge on the phosphate group of
phosphatidylcholine. A linear relation between zeta potential and PE
concentration was found. Absolute values of zeta potential were higher in PS
liposomes and showed an exponential dependence on the PS content. The
electrophoretic mobility depended not only on the percentage of aminophospholipid
but also on the size of vesicles. This behavior can be explained by the
relaxation effect. From geometrical considerations, it was possible to calculate
the theoretical surface charge densities. Comparing experimental with theoretical
values, an underestimation of zeta potential was found by the electrokinetic
classic theory in the experimental conditions used. Copyright 1998 Academic
Press.
PMID- 9756664
TI - Anomalous Colloidal Stability of Latex-Protein Systems.
AB - An experimental study on the colloidal stability of latex-F(ab')2 and latex-IgG
systems is described. The stability domains were obtained using a low-angle
scattering technique to measure the rates of aggregate formation and plotting the
stability ratio as a function of electrolyte concentration. The protein-coated
particles present an anomalous stability at high ionic strength when the
classical theory predicts aggregation. This observed deviation from DLVO behavior
appears for electrolyte concentrations above some critical bulk concentration
called critical stabilization concentration (csc). As we have suggested in
previous publications, the existence of an additional short-range repulsive
"hydration force" can explain this anomalous stability. In order to resolve more
fully if this anomalous stability at high ionic strength is due to the hydration
forces, the effects of pH, cation and anion type, temperature, and polyethylene
glycol (a dehydrating polymer) on the experimental stability are investigated.
Finally, the immunoreactivity of an anti-CRP F(ab')2-latex conjugate is studied
in reaction buffers with high ionic strength. Copyright 1998 Academic Press.
PMID- 9756665
TI - Microcalorimetric Study of Argon, Nitrogen, and Carbon Monoxide Adsorption on
Mesoporous Vycor Glass.
AB - The adsorption of argon, nitrogen, and carbon monoxide in porous Vycor glass has
been studied by volumetric and microcalorimetric methods and by thermoporometry.
Samples with particle sizes ranging from <50 to >200 um have been selected and
treated by sample controlled thermal analysis (SCTA). Subsequent characterization
indicates that the particle size has no influence on the pore texture and nature.
Thermal treatment, however, modifies the chemical nature of the surface. It would
seem that nitrogen and carbon monoxide assume a distinct mean orientation leading
to smaller effective cross-sectional areas than those usually accepted. Carbon
monoxide clearly distinguishes two different types of adsorption site for samples
treated at low temperature. Copyright 1998 Academic Press.
PMID- 9756666
TI - Shear-Induced Flocculation of Colloidal Particles in Stirred Tanks.
AB - Colloidal polystyrene and paramagnetic particles consisting of mixtures of
polystyrene and magnetite are used to experimentally investigate flocculation
kinetics in a stirred tank under turbulent shear flow. The effects of various
parameters-agitation speed, solution pH, ionic strength, particle size, and
particle concentration-on the flocculation rate are investigated. A trajectory
model applicable for shear-flow systems is formulated to describe particle
flocculation in stirred tanks. The collision efficiency of particles is obtained
from the limiting trajectory of one particle moving toward another and is a
function of interparticle forces and flow properties. The collision frequency is
determined as a function of particle size and energy dissipation. The
flocculation frequency is then determined by multiplying the collision frequency
by the collision efficiency and is incorporated into a population balance model
to predict the particle size evolution. Results suggest that the flocculation
rate is enhanced by increasing the agitation speed, even though the collision
efficiency is decreased at a higher agitation speed. It is also found that the
collision rate increases and the collision efficiency decreases as the particle
size ratio is increased. Results also suggest that the breakup rate of aggregates
in a turbulent shear flow could be significant and may need to be included in the
population balance modeling to correctly predict the evolution of particle size
distribution. Copyright 1998 Academic Press.
PMID- 9756667
TI - Analysis of Multicomponent Adsorption Close to a Dew Point.
AB - We develop the potential theory of multicomponent adsorption close to a dew
point. The approach is based on an asymptotic adsorption equation (AAE) which is
valid in a vicinity of the dew point. By this equation the thickness of the
liquid film is expressed through thermodynamic characteristics of the bulk phase.
The AAE makes it possible to study adsorption in the regions of both the normal
and the retrograde condensation. A simple correlation of the Kelvin radius for
capillary condensation and the thickness of the adsorbed film is established.
Numerical testing shows good agreement between the AAE and the direct
calculations, even if the mixture is not close to a dew point. Copyright 1998
Academic Press.
PMID- 9756668
TI - Evaluation of the Structure and Acid-Base Properties of Bulk Wood by FT-Raman
Spectroscopy.
AB - The structure of pine wood (Pinus silvestris L.) has been analyzed by FT-Raman
spectroscopy, taking birch wood and the wood components cellulose, hemicellulose
(xylan), and lignin as well as previously characterized wood resins as
references. The acid-base properties of bulk pine wood were evaluated by
comparing the spectra recorded before and after the treatment with various
solvents. After the treatment with the probe liquids having only a Lifshitz-van
der Waals (LW) component, it was found that the LW interactions in pine wood take
place without changing the main structure. After treatment with Lewis acid-base
active probe liquids, the spectra indicate that, e.g., the intense peak located
at approximately 2936 cm-1 (CH2 stretch) seems to disappear, suggesting that this
peak may be related to Lewis acidity. In addition, after treatment with a Lewis
acid, it was found that the intense peak located at approximately 1657 cm-1
(C&dbond;C) is shifted, relating to Lewis basicity. With the ratio approximately
2936/ approximately 1657 cm-1 as a measure of the acid-base properties of bulk
wood, a value of about 2.00 indicates that the bulk pine wood is largely acidic.
The pH determined supports the evaluation made by FT-Raman spectroscopy.
Copyright 1998 Academic Press.
PMID- 9756669
TI - Effect of Size Polydispersity on the Dielectric Relaxation of Colloidal
Suspensions: A Numerical Study in the Frequency and Time Domains.
AB - In this article, a systematic numerical study is described of the effect of the
polydispersity of suspensions of spherical particles on their dielectric
behavior, in both the frequency and time domains, starting from the model
proposed by DeLacey and White (J. Chem. Soc., Faraday Trans. 2 77, 2007 (1981))
for monodisperse suspensions. The distribution function of relaxation times,
characterizing the dielectric response of the systems, is also calculated. It is
found that in both the frequency and time domains the predicted behavior does not
differ in any essential way from the one obtained for a monodisperse suspension
with particle radius close to the volume-averaged mean radius of the polydisperse
system. Hence, no arguments related to polydispersity seem to be useful for
explaining the discrepancies frequently found between measured and calculated
dielectric increments in suspensions, namely, those concerning the magnitude of
the dielectric constant of the suspension (its low-frequency value), the value of
the characteristic or relaxation frequency, or the overall shape of the
relaxation pattern. Copyright 1998 Academic Press.
PMID- 9756670
TI - SAXS Study on Gelation Process in Preparation of Resorcinol-Formaldehyde Aerogel.
AB - RF aerogels were prepared by sol-gel polycondensation of resorcinol with
formaldehyde in a slightly basic aqueous solution and supercritical drying with
carbon dioxide. The aerogels were characterized by nitrogen adsorption and
density measurements. A small-angle X-ray scattering (SAXS) technique was applied
to the gelation process of RF hydrogels. The structure formation of the hydrogels
during the sol-gel transition was revealed by applying Guinier and power-law
equations to the SAXS data. At the initial stage of the synthesis of RF
hydrogels, small clusters of ca 2 nm consisting of branched polymeric species
formed, showing a mass fractal dimension. Then the clusters aggregated and formed
particles of ca 3-6 nm. These particles showed a surface fractal dimension. The
hydrogel structure was fixed by gelation and the particles grew to ca 4-7 nm.
Finally their surface became smooth by aging. The influence of the amount of
resorcinol, basic catalyst, and water used in the polycondensation on the porous
structures of the aerogels was explained by the structure formation model
proposed. Copyright 1998 Academic Press.
PMID- 9756671
TI - Precipitation of Barium and Calcium Naproxenate Particles of Different
Morphologies.
AB - Barium and calcium salts of naproxen, (+)-6-methoxy-alpha-methyl 2
naphtaleneacetic acid, were prepared by the controlled double jet precipitation
technique in the absence and in the presence of different surfactants. The nature
of the latter and agitation used in the precipitation process were critical
factors in determining the morphology and the size of the particles obtained,
consisting, as a rule, of aggregates of much smaller subunits, which were either
platelet or fiber like. Copyright 1998 Academic Press.
PMID- 9756672
TI - Kinetic-Diffusion-Controlled Adsorption and Desorption Kinetics on Planar
Surfaces.
AB - The adsorption and desorption kinetics of water-soluble associative polymers with
different molecular weights on the silicon wafers were studied by ellipsometry.
The parameters characterizing the adsorption and desorption processes such as (a)
the maximum amount of adsorbate adsorbed, Gammainfinity, (b) the equilibrium
constant, K(p), (c) the activation energy of adsorption, (-DeltaH), (d) the rate
constants for adsorption and desorption processes, Kad, Kdes, (e) the coefficient
of diffusion, D0, (f) the activation energy of the effective diffusion, Q, and
(g) the time needed to attain the equilibrium states for the adsorption and
desorption processes were calculated from the experimental ellipsometric data. It
is shown that the adsorption kinetics for mixtures over a wide range of
concentrations is governed by: (I) the kinetic adsorption at the interface, (II)
the kinetic adsorption at the interfaces as well as simultaneous diffusion,
and/or (III) diffusion. The existence of regimes (I), (II), and (III) for
adsorption and desorption kinetics are justified by using the experimental data
for the adsorption and desorption kinetics of water-soluble associative polymers
with different molecular weights of 12, 62, and 120 kg/mol. Copyright 1998
Academic Press.
PMID- 9756673
TI - An Adsorption Equation for an Ultrathin Fluid Film.
AB - Henry's law is found by applying the condition of extremum to the Gibbs function
of a fluid film. The resulting equation relates linearly the thickness of the
adsorbed layer to the external gas pressure. The equation reveals that the
coefficient of proportionality beta depends inversely on the saturation pressure
p0. It also shows that wetting effects are irrelevant. These results predicted by
the present model are in agreement with experiment. Copyright 1998 Academic
Press.
PMID- 9756674
TI - Diffusion in a Fractal System.
AB - The surface geometry of Vycor porous glass was examined by using the relative
permeability (PR) technique in a H2O/He system. At a water relative pressure of
approximately 0.3, a maximum is observed on the PR curve. This maximum is
explained in terms of geometrical changes taking place due to the deposition of a
water film on the internal Vycor surface. When the sample is dry, diffusion in a
fractal system is found to be more appropriate in describing the process. When
the sample is wet, the diffusion process obeys classical Knudsen theory for
smooth cylinders. Copyright 1998 Academic Press.
PMID- 9756675
TI - Low-level prenatal lead exposure and neurobehavioral development of children in
the first year of life: a prospective study in Shanghai.
AB - We used a prospective study design to assess the effects of prenatal low-level
lead exposure on the development of urban, inner-city children in Shanghai.
Umbilical cord blood samples wee consecutively collected from 605 live newborns.
Two hundred and fifty-seven samples were excluded from the study due to clotting.
Lead levels were determined on 348 cord blood samples. The geometric mean was 9.2
micrograms/dl. Based on their cord blood lead levels, infants were classified
into two exposure groups: 104 in a relatively low lead group (lead levels < or =
30 percentile), and 104 in a relatively high lead group (lead levels > or = 70
percentile). Seventy-five subjects failed to complete the study, and 133 babies
were included in the final cohort: 69 babies in the high lead group and 64 in the
low lead group. At 3, 6, and 12 months, the Bayley Scales of Infant Development
were administered and capillary blood lead levels were measured. Detailed
information was obtained on a wide range of variables relevant to infant
development. At all three ages, the Mental Development index (MDI) scores,
adjusted for confounders, were inversely related to the infants' cord blood lead
levels. The difference of the mean adjusted MDI scores between low and high lead
groups was 3.4 at 3 months, 6.3 at 6 months, and 5.2 at 12 months of age. These
differences were statistically significant at all time points. No significant
association between cord blood lead levels and the Psychomotor Development Index
(PDI) scores was detected at all three visits after adjustment for confounders.
Postnatal lead levels were unrelated to concurrent developmental status. We
conclude that prenatal low-level lead exposure, which is relatively common in
Shanghai, is associated with an adverse developmental impact on children through
the first year of life.
PMID- 9756676
TI - Medical costs and lost productivity from health conditions at volatile organic
compound-contaminated superfund sites.
AB - This paper estimates the health costs at Superfund sites for conditions
associated with volatile organic compounds (VOCs) in drinking water. Health
conditions were identified from published literature and registry information as
occurring at excess rates in VOC-exposed populations. These health conditions
were: (1) some categories of birth defects, (2) urinary tract disorders, (3)
diabetes, (4) eczema and skin conditions, (5) anemia, (6) speech and hearing
impairments in children under 10 years of age, and (7) stroke. Excess rates were
used to estimate the excess number of cases occurring among the total population
living within one-half mile of 258 Superfund sites. These sites had evidence of
completed human exposure pathways for VOCs in drinking water. For each type of
medical condition, an individual's expected medical costs, long-term care costs,
and lost work time due to illness or premature mortality were estimated. Costs
were calculated to be approximately $330 million per year, in the absence of any
remediation or public health intervention programs. The results indicate the
general magnitude of the economic burden associated with a limited number of
contaminants at a portion of all Superfund sites, thus suggesting that the burden
would be greater than that estimated in this study if all contaminants at all
Superfund sites could be taken into account.
PMID- 9756678
TI - Uptake of HgCl2 and MeHgCl in an insect cell line (Aedes albopictus C6/36).
AB - We studied the uptake mechanism of mercuric chloride (Hg) and methylmercuric
chloride (MeHg) in Aedes albopictus C6/36 cells. The uptake kinetics, together
with the effect of temperature and a metabolic inhibitor (2, 4-dinitrophenol) on
the mercury accumulation, were examined. Both amounts of internalized Hg and MeHg
increased linearly with the extracellular concentration. Initially, the influx
rate was high for both metal species but MeHg was found to accumulate seven times
faster than Hg. At longer exposure times it leveled off for Hg, while for MeHg,
the intracellular concentration decreased. Hg toxicity was not significantly
influenced by elevated temperatures; in contrast there was a marked decrease of
the LC50/24h value for MeHg. On the other hand, Hg accumulation was temperature
dependent but MeHg was not. The different toxicity and uptake rate of both
mercury compounds can be explained in terms of membrane permeability and target
site. For Hg the main target seems to be the plasma membrane, while MeHg readily
crosses this barrier and reacts with intracellular targets. 2, 4-Dinitrophenol
had no effect on the accumulation of Hg but that of MeHg was doubled. This
increased MeHg accumulation might be the result of the inhibition of an active
MeHg efflux mechanism; this is in agreement with the MeHg influx kinetics.
Despite these differences between Hg and MeHg, which probably result from their
physicochemical properties, our experiments indicate that, for both mercury
species, simple diffusion is probably the main way to entrance in Aedes cells.
PMID- 9756677
TI - Neurotoxic effects of low-level methylmercury contamination in the Amazonian
Basin.
AB - Many studies have demonstrated mercury contamination in the Amazonian ecosystem,
particularly in fish, a dietary mainstay of populations in this region. The
present study focused on potential health effects of this low-level methylmercury
exposure. The study was carried out in a village on the Tapajos River, a
tributary of the Amazon, on 91 adults inhabitants (15-81 years), whose hair
mercury levels were inferior to 50 mu/g. Performance on a neurofunctional test
battery and clinical manifestations of nervous system dysfunction were examined
in relation to hair mercury concentrations. Near visual contrast sensitivity and
manual dexterity, adjusted for age, decreased significantly with hair mercury
levels (P < 0.05), while there was a tendency for muscular fatigue to increase
and muscular strength to decrease in women. For the most part, clinical
examinations were normal, however, hair mercury levels were significantly higher
(P < 0.05) for persons who presented disorganized movements on an alternating
movement task and for persons with restricted visual fields. These results
suggest dose-dependent nervous system alterations at hair mercury levels below 50
micrograms/g, previously considered a threshold for clinical effects. The profile
of dysfunction in this adult population is consistent with the current knowledge
on methyl-mercury poisoning. The long-term implications of these findings are
unknown and need to be addressed.
PMID- 9756679
TI - The impact of low technology lead hazard reduction activities among children with
mildly elevated blood lead levels.
AB - This prospective environmental intervention study was conducted to determine the
impact of low-technology lead hazard reduction activities among children with
mildly elevated blood lead levels. Children whose homes had severe lead hazards
were automatically assigned to the intervention group. Children whose homes had
lesser hazards were randomly assigned to the intervention group or comparison
group. The one-time intervention focused mainly on cleaning and repainting window
areas and educating caregivers to maintain effective housekeeping techniques.
Changes in blood lead and dust lead loading levels were observed following the
interventions. Analysis of covariance was used to adjust comparisons of
postintervention levels for preintervention levels and other variables. The lead
hazard reduction activities were associated with a modest decline in blood lead
levels among children with severe hazards. The magnitude of the decline depended
on the confounder that was controlled; the majority ranged from-1.1. to-1.6
microgram/dL. A moderate reduction in window well dust lead loading levels was
also observed. While low-technology lead hazard reduction measures appeared to be
an effective secondary prevention strategy among children with severe household
lead hazards, larger studies are needed to confirm these results.
PMID- 9756681
TI - Handling and Disposal of Chemical Products/Management of Hospital Waste
Substances and Residues.
PMID- 9756680
TI - The contribution of lead-contaminated house dust and residential soil to
children's blood lead levels. A pooled analysis of 12 epidemiologic studies.
AB - In 1992, the U.S. Congress passed the Residential Lead-Based Paint Hazard
Reduction Act, which requires the promulgation of health-based dust lead and soil
lead standards for residential dwellings to prevent undue lead exposure in
children. Unfortunately, the levels of lead in house dust and soil that are
associated with elevated blood lead levels among U.S. children remain poorly
defined. This pooled analysis was done to estimate the contributions of lead
contaminated house dust and soil to children's blood lead levels. The results of
this pooled analysis, the most comprehensive existing epidemiologic analysis of
childhood lead exposure, confirm that lead-contaminated house dust is the major
source of lead exposure for children. These analyses further demonstrate that a
strong relationship between interior dust lead loading and children's blood lead
levels persists at dust lead levels considerably below the U.S. Department of
Housing and Urban Development's current postabatement standards and the
Environmental Protection Agency's guidance levels. Finally, these analyses
demonstrate that a child's age, race, mouthing behaviors, and study-site specific
factors influence the predicted blood lead level at a given level of exposure.
These data can be used to estimate the potential health impact of alternative
health-based lead standards for residential sources of lead exposure.
PMID- 9756682
TI - Editorial
PMID- 9756683
TI - Small mammal populations and community under conditions of extremely high
thallium contamination in the environment.
AB - Studies were carried out in the vicinity of a zinc smelter in southern Poland, 50
km northwest of Krakow, where the previous measurements with another
bioindication method revealed huge thallium levels in the environment. The
mammals (106 individuals in total) were captured in four wooded areas situated
1.5 to 2.5 km in various directions from the plant and in two reference sites,
located far from industrial emission sources. Very high Tl levels were found in
livers and kidneys of all mammals examined from the two areas nearest the
smelter. Bank voles were the most loaded (maximum Tl in kidneys, 34.27
microgram/g dry mass; in livers, 14.53 microgram/g; values from unpolluted areas
were below the detection limit, 0.07 microgram/g). A distinct decrease in the
amount of hair-a characteristic of thallium poisoning-was observed in several
individuals. The extreme case was a wood mouse with the rear half of its body
almost entirely hairless (!). Densities of single populations and the whole
community were very low, up to 4.8 individuals/ha, including insectivores.
Numerical proportions between species were changed in comparison to unpolluted
areas. The age structure was deformed, with a disproportionate small
participation by young generations. Among the males studied, only sexually
inactive individuals were found. The condition of populations and the community
of small mammals living here was much worse compared with data from the
surroundings of other zinc smelters.
PMID- 9756684
TI - Effect of heavy metals and storage time on two types of forest litter: basal
respiration rate and exchangeable metals.
AB - Two types of forest litter, MOR and MULL, were treated with 0 (control), 25, 100,
400, 1600, and 6400 mg kg-1 Cd, Cu, Pb, or Zn after different storage times (35,
75, and 125 days at approx 5 degreesC). Highly significant effects on respiration
rate were observed for dose of heavy metals, type of litter, type of metal, and
storage time. The respiration rate of untreated MULL litter was lower than that
of untreated MOR in all incubations, and the slope of the relation to the dose of
metals was steeper for MOR. Respiration rates after storage were lower than in
fresh litter, and the slope of the relation between respiration rate and metal
dose was less steep after storage. In the first incubation, MULL litter was more
sensitive to Cd, Cu, and Pb and less sensitive to Zn than MOR litter. After 125
days of storage, no single significant effect was found in MULL litter, whereas
in MOR litter all metals still inhibited respiration rate significantly. The
relative toxicity of metals was similar for both litter types, and the average
EC50respiration values were (mg kg-1) Cu=3880, Zn=5610, Cd=6320, and Pb=24800.
The percentages of exchangeable metals (1 M NH4OAc, pH=7) in MULL litter were
lower on average than in MOR litter, and the order of solubility of the metals
was Cd>Zn>Pb>Cu. Storage caused no significant difference in the average
percentage of exchangeable metal. The highest doses of heavy metals increased the
amounts of Ca, K, Mg, and Na extracted.
PMID- 9756685
TI - Impact assessment of a wastewater treatment plant effluent using the fish
biomarker ethoxyresorufin-O-deethylase: field and on-site experiments.
AB - The impact of a wastewater treatment plant (WWTP) effluent was assessed with the
fish biomarker ethoxyresorufin-O-deethylase (EROD) using field and on-site
laboratory experiments. EROD activity was measured in chub (Leuciscus cephalus)
and stone loach (Noemacheilus barbatulus) caught at three sites of the Chalaronne
River (southeast France). Liver somatic index (LSI) and organochloride
bioaccumulation in muscle were estimated for chub only. In September, EROD
activity and LSI of chub increased significantly between the sites above and
below the WWTP effluent discharge. EROD induction detected in chub was confirmed
by on-site tank experiments. EROD levels were determined in juvenile rainbow
trout (Oncorhynchus mykiss) and mirror carp (Cyprinus carpio) exposed to
different concentrations of the WWTP effluent and river water for 16 days. After
a 4-day exposure, EROD activities of the carp exposed to the effluent increased
significantly compared with the control. The response was linked to the effluent
concentration and was stable with exposure time. WWTP effluent induced EROD
activity, whereas organic and metal analyses, performed on fish muscle and
sediment, did not indicate any difference between upstream and downstream of the
discharge.
PMID- 9756686
TI - Sublethal effects of repeated intraperitoneal cadmium injections on rainbow trout
(Oncorhynchus mykiss).
AB - Acute and chronic effects of cadmium have been widely described for different
aquatic organisms and exposure routes. However, there is clearly a lack of
information on the potential of cadmium to cause genotoxic effects. This work
presents genotoxic and nongenotoxic parameters analyzed in cadmium-exposed
rainbow trout. The assessment was performed for sublethal levels after long-term
exposure using six intraperitoneal injections of 0.5 mg/kg (Day 1), 1 mg/kg (Days
3, 7 and 11), and 2 mg/kg (Days 15 and 19) to allow precise estimation of the
dose. Cadmium accumulation in target tissues, essential metal mobilization by
cadmium at the subcellular and tissue levels, and induction of metallothioneins
were selected as exposure and effect parameters. Induction of micronuclei and
variation in DNA content (expressed as variation coefficient in the G1 phase of
the cell cycle) in blood cells, determined by flow cytometry, were selected as
biomarkers for genotoxic effects. Cadmium accumulation, induction of
metallothioneins, and mobilization of essential metals at the subcellular level
were observed in different organs in response to cadmium exposure. The highest
metallothionein induction was observed in liver, reaching 270+/-90 nmol/g wet
tissue in treated fish versus 2.68+/-1.1 nmol/g wet tissue in controls. The
highest cadmium accumulation was also observed in the liver (27.8+/-9.5 microgram
Cd/g wet wt in treated animals versus 1.0+/-1.7 in the control group). However,
no genotoxic effects were observed in blood cells. The frequency of micronuclei
was 0.012+/-0.008 for the control group and 0.013+/-0.021 for treated animals.
The variation coefficient of G1-phase nuclei was 3.61+/-0.66 and 3.22+/-0.29 for
control and cadmium-exposed groups, respectively. Thus, it is concluded that
under the experimental conditions employed here, treatment of rainbow trout with
cadmium chloride at doses that produce significant toxicological alterations at
the tissue and subcellular levels does not provoke observable alterations in the
genotoxic parameters considered in this study.
PMID- 9756687
TI - OH radical reactivity of pesticides adsorbed on aerosol materials: first results
of experiments with filter samples.
AB - Preliminary results of a new method to investigate the OH radical reactivity of
semi-volatile organic compounds (e.g., pesticides) are presented. Terbuthylazine,
simazine, sodium benzoate, and bromoxynil were adsorbed on highly disperse
silicon dioxide powder as an unreactive carrier at a thickness well below one
monolayer. The coated material was suspended in air as an aerosol, sampled on
filters, and exposed in an 840-liter Duran chamber to OH radicals, produced by
photolysis of hydrogen peroxide in the gas phase. Sunlamps on top of the chamber
were used as cold light sources [T(aerosol) approximately 25 degreesC]. OH
radical concentrations (10(5)290 nm) of cholorotahlonil,
dichlobenil, chloroxynil, bromoxynil, and ioxynil in aqueous, pH-buffered, and
organic solutions and the calculation of the quantum yields. The photolysis of
chlorothalonil in water is low, with a corresponding low quantum yield
(Phi=0.0001). Dichlobenil is photostable under the laboratory conditions used.
The photoreactivity of bromoxynil and ioxynil was found to be comparable in
aqueous solutions and about three times lower with respect to chloroxynil. The
quantum yields obtained in water of chloroxynil, bromoxynil, and ioxynil are
Phi=0.0060, 0.0093, and 0.0024, respectively. Half-lives of the pesticides in the
environment with respect to direct irradiation are estimated using UV spectra and
quantum yields as input variables obtained in the laboratory.
PMID- 9756689
TI - Detection of DNA strand breaks in isolated mussel (Mytilus edulis L. ) digestive
gland cells using the "Comet" assay.
AB - Isolated mussel (Mytilus edulis L.) digestive gland cells were analyzed using the
single-cell gel electrophoresis or "comet" assay to assess the ability of
potential aquatic contaminants to induce DNA strand breaks (SBs) and to
investigate the potential application of this technique as part of an aquatic
biomonitoring regime. Freshly prepared cell suspensions from digestive gland were
exposed in vitro to hydrogen peroxide (H2O2, 0-200 microM), 3-chloro-4
(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX, 0-200 microM), benzo[a]pyrene
(BaP, 0-200 microM), 1-nitropyrene (1-NP, 0-250 microM) and nitrofurantoin (NF, 0
1000 microM) for 1 h in the dark at 15 degreesC in the presence of the DNA repair
inhibitor cytosine-beta-D-arabinofuranoside (araC). DNA strand breakage was
measured using the comet assay. There were significant concentration-dependent
increases in the percentage of DNA in the comet tail (mean values+/-SD) for all
doses compared with controls (P<0.05) with H2O2 (up to 61.4+/-5.1% at 100
microM), MX (up to 34. 3+/-2.2% at 200 microM), BaP (up to 24.7+/-5.1 at 100
microM), 1-NP (up to 54.7+/-5.0% at 200 microM), and NF (up to 68.1+/-4.5% at 500
microM). There was a decrease (P<0.05) in viability (eosin Y exclusion) of
exposed compared with control cells at 200 microM H2O2 and BaP only. This study
has demonstrated the potential of the comet assay to detect DNA strand breakage
at subcytotoxic concentrations of a range of agents, some of which require
metabolic activation. This may provide a sensitive, but nonspecific, molecular
biomarker of genotoxicity.
PMID- 9756690
TI - Ecotoxicological assessment of ashes and particulate matter from fluidized bed
combustion of coal.
AB - Toxicity of ash and particulate matter from the gases generated in coal fluidized
bed combustion (FBC) has been determined by the Microtox assay according to the
standard leachate procedure. Results are compared with the polycylic aromatic
hydrocarbon (PAH) content of the particulate matter, which was determined by
fluorescence spectroscopy. Although PAHs are considered highly toxic compounds,
the low ecotoxicity values obtained could be explained by the low solubility of
the compounds in water. The Microtox assay may underestimate the toxicity of
water-insoluble compounds unless they are previously extracted with an organic
solvent. Nevertheless, this type of assay can be very useful for measuring the
potential toxicity of residues when exposed to water sources such as rain water
and the risk of the components being dissolved and transported by runoff water.
PMID- 9756691
TI - Memory effects in the action of ozone on conifers.
AB - Conifers are known to possess relative ozone tolerance in short-term experiments.
A scenario for ozone damage of conifers is now derived from the first exposure
experiments in which both the initial biochemical response phase and delayed
visible symptom development were studied. A number of early biochemical ozone
responses could be detected in Norway spruce (Picea abies [L.] Karst.) and Scots
pine (Pinus sylvestris L.). The stress metabolite catechin persisted over several
months. In the year following ozone treatment of spruce, decreases in pigment
content and photosynthetic capacity, as well as development of visible symptoms
(chlorosis, banding), were determined in the needle age classes previously
exposed to an accumulated hourly ozone dose above 40 ppb (AOT40) of >/=60-80 ppm
small middle doth. The visible symptoms developed during spring emergence of the
new flush. In the case of Scots pine, an ozone dose (AOT40) of >/=30 ppm small
middle doth caused the premature shedding of needles 9 months after treatment.
The delayed symptoms of both spruce and pine occurred during known phases of
endogenous stress. The symptoms appeared to reflect an ozone "memory" imprinted
by the induced early stress reactions. Ambient AOT40 ozone doses in Central
Europe are in the range 4 and 50 ppm small middle doth per growing season. Ozone
is proposed to potentially damage conifers through memory effects ("abiotic"
pathway) or through predisposition for pathogen attack ("biotic" pathway).
PMID- 9756692
TI - Influence of an aquatic humic acid on the bioconcentration of selected compounds
in Daphnia magna.
AB - Several chemicals covering a wide range of octanol-water partition coefficients
were assayed for their bioconcentration in Daphnia magna in the presence of an
aquatic humic acid. Assuming the properties of the humic acid used were similar
to those known for organic matter from soils, the influence of the aquatic humic
acid on physicochemical moderation of bioconcentration could not be demonstrated
experimentally in a log Kow range of the chemicals between 2 and 6. Thus, the
lipophilic character of the aquatic humic acid and the related effect of
solubilization of the chemicals in the aqueous phase are much less than expected.
This result is confirmed by determining the octanol-water partition coefficient
of the aquatic humic acid. Comparing this value with log Kow values of humic
acids of terrestrial origin, it can be clearly demonstrated that the
lipophilicity of the aquatic humic acid is lower by a factor of 50.
PMID- 9756693
TI - Establishment of a simple cleanup procedure and bioassay for determining 2,3,7,8
tetrachlorodibenzo-p-dioxin toxicity equivalents of environmental samples.
AB - The study was aimed at establishing a bioassay for the determination of 2,3,7,8
tetrachlorodibenzo-p-dioxin toxicity equivalents (TEQs) in environmental samples.
Specifically, development of a rapid cleanup procedure adapted to the needs of
the bioassay and simplification of the measurement of its endpoint, the induction
of 7-ethoxyresorufin O-deethylase (EROD) in rat H4IIEC3/T hepatoma cells, were
desired. The results indicate that a single "sandwich" column suffices to remove
substances that may interfere with the bioassay from extracts of various
environmental matrices such as sewage sludge, compost, soil, sediment, fly ash,
tissue filter dust, and fire residue. The cumbersome conventional in vitro assay
for EROD activity on cells exposed to the test material in culture plates could
readily be replaced by a simple assay on intact cells grown and treated in 96
well microtiter plates. TEQ values obtained from the bioassays were consistently
higher than those derived from chemical analysis of dibenzo-p-dioxins/furans and
biphenyls by a factor of 1.5-3.0 depending on the matrix used. The results
indicate that this bioassay, which combines a simple cleanup and a rapid
procedure for measuring biological effects, offers a cost- and time-effective
alternative to chemical analysis when screening large numbers of samples from
complex environmental matrices.
PMID- 9756694
TI - Role of algae in fate of carcinogenic polycyclic aromatic hydrocarbons in the
aquatic environment.
AB - Polycyclic aromatic hydrocarbons (PAHs) represent an ecotoxicologically relevant,
combustion-related substance group. The bioconcentration and transformation of a
priority PAH, benzo[a]pyrene (BaP), by brown (Fucus vesiculosus and Chorda
filum), red (Furcellaria lumbricalis), green (Enteromorpha intestinalis, and
Cladophora glomerata), and chara (Chara aspera) algae have been studied. A flux
budget was made of the amounts of BaP that are accumulated and metabolized by
different algae during an estimated time. The results indicated that of all the
BaP consumed, 89-99% was found in the biomass of Fucus, an insignificant part was
in the solution, and the remainder (up to 4%) was not recovered, i.e., was
considered to have been metabolized. For green and chara algae the proportion of
transformed PAHs was more essential, 42-49%. The transformation of BaP in marine
and freshwater algae is species specific and depends on the presence and activity
of enzymes localized in the plant cells. The most important enzyme systems for
detoxification of BaP are o-diphenol oxidase, cytochrome P450, and peroxidase.
The data obtained indicate the important role of marine and freshwater algae in
the fate of carcinogenic PAHs in the environment.
PMID- 9756695
TI - Chemical speciation dynamics and toxicity assessment in aquatic systems.
AB - The key to risk assessment of contaminant effects in the environment (water,
sediments, soil) is the ability to document cause-and-effect relationships. In
ecotoxicological research, biotic responses are related to quantified contaminant
concentrations, which in most cases are still expressed in terms of "total
elemental concentration" and not in terms of "elemental species." However, it
becomes evident that the abundance and distribution of pollutants in the
environment, their bioavailability, and their toxicity to aquatic and terrestrial
organisms (including humans) can often be better understood in terms of
"elemental species." The persistence, mobility, chemical reactivity, sorption
dynamics, and so on of contaminants in soil and water are governed by a range of
changing physicochemical parameters (pH, temperature, organic matter, suspended
solids, etc.), which finally dictate the effects at the organism level. Examples
are given to demonstrate that knowledge of the nature and concentration of
elemental species of pollutants is crucial in assessing the impact of
contaminants on aquatic ecosystems. The experimental approach to evaluate
chemical speciation dynamics in relation to toxic effects is illustrated in a
case study on the acute toxicity of aluminum in mixing zones at the confluence of
rivers with different pH values. This study under nonequilibrium ecosystem
conditions has provided new insights into the mechanism of toxicity of aluminum
to freshwater organisms. In conclusion, an integrative approach by environmental
chemists and ecotoxicologists is recommended to evaluate environmental pollution.
Studies on the assessment of the impact of changing physicochemical parameters on
the transformation kinetics and chemical speciation of pollutants, which finally
determine toxicity and bioconcentration in organisms, deserve more attention in
environmental toxicology.
PMID- 9756696
TI - Metallothioneins in Arctic bivalves.
AB - In the framework of an International Association for the Promotion of Cooperation
with Scientists from the Independent States of the Former Soviet Union (INTAS)
Project on biodiversity and adaptation strategies of Arctic coastal marine
benthos, research was focused on the role of metallothioneins as a possible
indicator of the effect on animals and availability of trace metals in the
Arctic. Metallothioneins are low-molecular-weight, cysteine-rich proteins known
to be induced by high environmental levels of trace metals. Specimens of Macoma
balthica and Mytilus edulis were collected along several Arctic estuaries in the
White and Pechora seas; whole tissues for M. balthica and the digestive gland and
gills for M. edulis were dissected, frozen in liquid nitrogen, and lyophilized
onboard. Metallothionein concentrations were determined by a polarographic assay.
From the same stations organisms and sediments were also collected for metal
analysis. The results revealed significant differences in metallothionein
concentrations among the stations for M. balthica. Similar, although less marked,
differences were also obtained in the organs of M. edulis. Data on
metallothionein were compared with trace metal concentrations in both the
organisms and sediments. Also, the relationship with abiotic factors (salinity)
and biological variables (size of sampled organisms) was determined. In
particular, biological variables seemed to influence metallothionein
concentration in the organisms and their effect should be carefully considered
for a correct assessment of differences between stations.
PMID- 9756697
TI - Use of DNA fingerprinting to detect genotoxic effects.
AB - The effects of environmental pollutants on organisms may be monitored in a number
of ways and at different levels. In the case of genotoxic chemicals, the effects
on the DNA may be monitored using a number of biomarker assays capable of
detecting phenotypic changes as a result of mutation, gross chromosomal
abnormalities, unscheduled DNA synthesis, DNA adducts (e.g., by 32P postlabeling
or by ELISA) and DNA strand breaks (e.g., by the alkaline unwinding assay or the
comet assay); the sensitivity and specificity of these assays are variable.
Recent developments in molecular biology such as DNA fingerprinting and gene
amplification by the polymerase chain reaction (PCR) offer new possibilities for
detecting DNA damage. In this laboratory, whether an alternative biomarker assay
(using DNA fingerprinting by arbitrarily primed PCR) can reveal differences in
the DNA fingerprints of individuals from control and polluted areas was
investigated. The results indicate that DNA fingerprinting by arbitrarily primed
PCR offers a useful alternative biomarker assay for detection of the genotoxic
effects of environmental pollutants.
PMID- 9756698
TI - Biochemical markers for differentiation of exposures to nonplanar polychlorinated
biphenyls, organochlorine pesticides, or 2,3,7, 8-tetrachlorodibenzo-p-dioxin in
trout liver.
AB - The effects of a single intraperitoneal dose of the prototypical contaminant
nonplanar 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153, 50 mg/kg), p,p'-DDE (50
mg/kg), or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 200 ng/kg) on the
activities of hepatic detoxification enzymes were examined in the liver of
immature rainbow trout (Oncorhynchus mykiss). Different modulations of the tested
xenobiotics on microsomal cytochrome P450-dependent testosterone hydroxylase
activities were found: PCB 153 specifically induced 16beta-hydroxylase activity,
whereas p,p'-DDE decreased cytochrome P4503A-dependent 6beta-hydroxylation as
well as 16alpha- and 2alpha-hydroxylation. TCDD did not modulate testosterone
hydroxylase activities, but a strong induction of cytochrome P4501A activity was
observed after TCDD administration; hence, cytochrome P4501A is not involved in
the hydroxylation of testosterone. Trout hepatic microsomal glutathione S
transferase (GST) activity, enhanced by all the xenobiotics tested, was found to
be a sensitive nonspecific biochemical marker of oxidative stress; cytosolic
glutathione reductase was a less sensitive indicator of oxidative stress and was
induced significantly only by treatment with p,p'-DDE. Cytosolic GST activity
toward ethacrynic acid (GST-ETHA) was induced by PCB 153 or p,p'-DDE, but not by
TCDD. Modulations of hepatic microsomal testosterone hydroxylase activities and
induction of GST-ETHA appeared to be suitable biochemical markers of acute
exposure to nonplanar PCBs and organochlorines that do not induce cytochrome
P4501A enzymes in rainbow trout, whereas microsomal GST and cytosolic glutathione
reductase may become early biochemical indicators of oxidative stress.
PMID- 9756699
TI - Buffer zones for reducing pesticide drift to ditches and risks to aquatic
organisms.
AB - Pesticide drift from field sprayers fitted with different types of spray nozzles
was investigated under various wind speed conditions. Droplet drift was measured
adjacent to the sprayed field, on the ditch bank, and in the ditch. Measurements
were carried out in the normal sprayed situation and with an unsprayed buffer
zone 3 or 6 m wide. The results indicate that there are major differences between
spray nozzles. Drift deposition increases with wind speed. In the sprayed
situation and with a wind speed of 0.5 m/s, there was a maximum of 6.0% drift
deposition halfway down the ditch bank and no drift deposition in the ditch. At 3
m/s wind speed these figures are 25.1 and 2.2%, respectively. At 5 m/s wind
speed, 7.2% drift deposition was measured in the ditch. Risk assessment (cf.
SLOOTBOX model) carried out with 17 pesticides used in the study area indicated
that at this wind speed, 8 of the 17 pesticides investigated posed a risk to
aquatic organisms. Creation of a 3-m buffer zone decreases drift deposition in
the ditch by a minimum of 95%. Adjacent to the buffer zone only 4 of the 17
pesticides investigated posed a (minor) risk to aquatic organisms. With a 6-m
buffer zone no drift deposition in the ditch could be measured (wind speed
maximum, 4.5 m/s). Creating unsprayed crop edges offers good possibilities for
the protection of aquatic ecosystems. Socioeconomic research among farmers
indicates that buffer zones, such as unsprayed cereal edges and unsprayed grass
strips, could well be adopted in agricultural practice.
PMID- 9756700
TI - Some considerations on the impact on ecological chemical principles in practice
with emphasis on gold mining and cyanide.
PMID- 9756701
TI - Accumulation of cadmium in and its effect on bank vole tissues after chronic
exposure.
AB - Cadmium is one of many metals that are not physiologically or biochemically
essential to organisms. This element is extremely dangerous as it is easily
absorbed and remains in tissues for a long time. Long exposure to high doses of
cadmium may cause biochemical and functional changes in some critical organs. In
this study, wheat grains contaminated with cadmium chloride were used to test the
influence of cadmium on male bank voles (Clethrionomys glareolus). Doses used in
the experiment were environmentally realistic: 0.25 microg g-1 (control), 15
microg g-1, and 40 microg g-1 cadmium (dry weight). The animals were given
cadmium-contaminated food and clean water ad libitum for 3 and 6 months. After
these exposures, the animals were killed and the kidneys, liver, and testes from
each vole were collected for analyses. The concentrations of Cd, Cu, Zn, and Fe
in the tissues were determined with an atomic absorption spectrophotometer. The
formalin-fixed testes, kidneys, and part of the liver were embedded in paraffin
and then stained with hematoxylin and eosin. Cadmium accumulation in the tissues
was directly proportional to dose. The highest cadmium concentrations were found
in the kidneys of animals fed the highest dose of cadmium. Histological
examination of the tissues revealed some pathological changes in the structure of
kidneys, liver, and testes.
PMID- 9756702
TI - Short- and long-term effects of the pyrethroid insecticide fenvalerate on an
invertebrate pond community.
AB - Direct and secondary effects of fenvalerate on the structure of pond ecosystems
were studied in six freshwater mesocosms simulating natural fish-free eutrophic
ponds. Exposed mesocosms were compared with nonexposed ones and the effects of
the added compound on the macroinvertebrate community were followed during three
vegetation seasons (years) in two mesocosms. Exposure to fenvalerate at 1.3 and
0.54 microg liter-1 resulted in structural changes in the macroinvertebrate
community. The insecticide was directly lethal to insects and other arthropods,
but indirect community changes were also observed. For example, after exposure
there was a remarkable (> 10-fold) increase in oligochaetes (Stylaria lacustris),
probably caused by reduced predation and interspecific competition for food. When
predators (insects) recolonized the system, the oligochaetes decreased in
abundance and were replaced by ostracods (Herpetocypris reptans), which use
similar food resources but are less susceptible to predation. The marked increase
in these two taxa is probably explained by the mass death of arthropods,
resulting in increased food availability. More than 2 years after treatment, the
most exposed system was still different compared with nonexposed ones, suggesting
that nonpersistent pesticides may produce detrimental effects resulting in long
term changes at the ecosystem level of organization.
PMID- 9756703
TI - Evaluation of heavy metal sediment toxicity in littoral ecosystems using
juveniles of the fish Sparus aurata.
AB - The toxicity of sediments from two littoral ecosystems of the Gulf of Cadiz was
tested using juveniles of the fish Sparus aurata (seabream). Concentrations of
total carbon and nitrogen, organic carbon, 14 heavy metals (Fe, Mn, Cu, Zn, Pb,
Cd, Ag, Hg, As, Sn, V, Ni, Co, Cr), and the surfactant linear alkyl
benzenesulfonate (LAS) in the sediments were measured. Chemical analysis was
performed in the stations to determine the degree and nature of contamination.
Four different endpoints were selected in the toxicity test: survival,
superficial alteration, hematocrit analysis, and histological damage. After 14
days, survival, superficial alteration, and hematocrit analysis did not reveal
effects of the different sediments tested. The histological and cellular damage
revealed a more sensitive response to measured chemicals in sediments and they
were found to be a powerful tool to evaluate sediment toxicity effects.
Semiquantitative evaluation of the histological damage demonstrated correlation
with sediment concentrations of some of the heavy metals (Cr, Cd, Pb, Ag, Cu) and
the surfactant (LAS). Data derived from chemical concentrations and toxicity
tests were assembled by multivariate statistical techniques (principal components
analysis) to identify the ranges of chemical concentrations associated with an
adverse effect. The results obtained, as suggested by site-specific sediment
quality values, were the following: Cr>/=90.2; Cd>/=1.24; Pb>/=52.5; Ag>/=0.68;
Cu>/=71.2; LAS>/=8.7 mg kg-1 of dry sediment. These results are mainly in
concordance with studies performed in other areas of the world and therefore
support wide application of the method.
PMID- 9756704
TI - Liver energy metabolism of Anguilla anguilla after exposure to fenitrothion.
AB - This paper deals with the effect of fenitrothion (0.04 mg/liter) on the energy
metabolism of the European eel, Anguilla anguilla, and its recovery from
intoxication. Various parameters such as glycogen, lactate, proteins, total
lipids, and glucose in eel liver and blood were analyzed after 2, 8, 12, 24, 32,
48, 56, 72, and 96 h of fenitrothion exposure. Subsequently, the fish were
allowed recovery periods of 8, 12, 24, 48, 72, 96, 144, and 192 h in clean water,
and the same parameters were evaluated. Liver glycogen and lipid contents
decreased significantly during the exposure, while blood glucose levels increased
markedly. Liver and blood lactate values increased during pesticide exposure,
while proteins were decreased in comparison to unexposed controls. Most of the
metabolic disorders did not persist after less than a week of recovery in clean
water. The observed effects of fenitrothion on fish metabolism are discussed in
relation to a stress syndrome, and probable reasons for alterations are also
discussed.
PMID- 9756705
TI - Toxicity of ozone to fish larvae and Daphnia magna.
AB - Ozone can be used as an alternative to chlorination to control biofouling in
cooling water systems. The possible negative environmental impact of a discharge
of ozone-containing cooling water was investigated. The acute toxicity of
dissolved ozone was determined for fish larvae of three species [Cyprinus carpio
(at 27 degrees C), Leuciscus idus (at 27 degrees C) and Clarias gariepinus (at 32
degrees C)] and to Daphnia magna (at 21 and 27 degrees C). The results indicate
that ozone is very harmful to aquatic life. Daphnids are more sensitive to ozone
than fish larvae. The mean 48-h LC50 value for the larvae amounts to about 35
microg/liter, while the 48-h NOEC for D. magna was 11 microg/liter (at 21 degrees
C). It was concluded that, to protect aquatic life, discharged cooling water
should not contain any dissolved ozone. This can be achieved in practice by
mixing the treated cooling water with a source of organic substances before
discharge, as free ozone will react immediately with organic matter and thus
disappear.
PMID- 9756706
TI - Study of alterations produced by cadmium and cadmium/lead administration during
gestational and early lactation periods in the reproductive organs of the rat.
AB - Administration of cadmium (10 mg/liter) and cadmium+lead (300 mg/liter) via
drinking water to Wistar rats during gestation and early lactation until delivery
and (5 days after parturition) damaged pup reproductive systems. The effects are
additive in the decreased gonad weight and additive or even synergistic in the
reduced DNA gonadal content. The effects on protein reduction are similar for
both cations. In the testes, the effects of cadmium are more important in the
reduction of seminiferous tubule diameter, whereas the effects of lead are more
overt in the reduction of the number of prospermatogonia.
PMID- 9756707
TI - Modulation of drug-metabolizing systems by bacterial endotoxin in carp liver and
immune organs.
AB - This report describes a study of the effects of bacterial endotoxin
[lipopolysaccharide (LPS)] on cytochrome P450 levels and ethoxyresorufin O
deethylase (EROD) and glutathione S-transferase (GST) activities in liver and two
main immune organs of carp: spleen and head kidney. Also studied was the paucity
of the carp drug-metabolizing system in an environment subject to pollution by a
polycyclic aromatic hydrocarbon, 3-methylcholanthrene (3MC), when fish respond to
an immune activation by lipopolysaccharide (LPS). In the presence of bacterial
endotoxin the basal cytochrome P450 levels were decreased in liver and spleen.
EROD activity was increased in liver and basal GST activity was increased in
spleen. When fish were treated concomitantly with 3MC and LPS, a suppression of
cytochrome P450 induction in liver and head kidney was observed. EROD activity
induced by 3MC was not modified by administration of LPS. GST activity was
suppressed by treatment with LPS and inducing agent in liver and head kidney. In
the present study it was found that endotoxin can have profound and differential
effects on fish basal biotransformation of drugs in the liver and immune organs.
Also, the induction of biotransformation enzymes by 3MC was modified when fish
responded to an immune stimulation.
PMID- 9756708
TI - Osmotic effects as a factor modifying insecticide toxicity on Aedes and Artemia.
AB - Euryhaline species are more tolerant of various insecticides under isosmotic
conditions. Two euryhaline species, Aedes taeniorhynchus (Wiedemann) and Artemia
sp., were exposed to four insecticides (aldicarb, dimethoate, imidacloprid,
tebufenozide), under isosmotic and hyperosmotic conditions. Mortality under these
two osmotic conditions was observed and compared to evaluate salinity as a
contributing factor to insecticide toxicity. Artemia was more tolerant of all
chemicals tested than A. taeniorhynchus under isosmotic conditions based on the
percentage mortality observed. Mortality of Artemia under isosmotic conditions
was dependent on the length of exposure; A. taeniorhynchus did not exhibit time
dependence. Less mortality was observed in populations of both test species under
isosmotic conditions compared with hyperosmotic conditions. However, the
variation in mortality due to exposure to test chemicals was of greater magnitude
in A. taeniorhynchus than Artemia. This result indicates that higher salinity is
a greater stress on A. taeniorhynchus than Artemia when exposed to the test
insecticides at the concentration ranges tested in this study.
PMID- 9756709
TI - The freshwater river crab, Potamonautes warreni, as a bioaccumulative indicator
of iron and manganese pollution in two aquatic systems.
AB - The aim of this study was to determine the potential use of the freshwater river
crab, Potamonautes warreni, as a bioaccumulative indicator of iron and manganese
pollution in aquatic ecosystems. Water and sediment analysis of the two study
sites (Germiston Lake and Potchefstroom Dam) revealed that while levels of
manganese were higher in Germiston Lake, iron concentrations were higher in
Potchefstroom Dam. Metal analysis of P. warreni revealed that while the crabs
from Potchefstroom Dam contained slightly higher iron levels than those from
Germiston Lake, manganese concentrations in P. warreni from the latter site were
significantly higher than those in the crabs from the former site. Iron and
manganese levels in these organisms were influenced by the size, mass, and sex of
the crabs on occasion, but these relationships were not always consistent at both
of the sites. The results of this study clearly indicate that the ultimate levels
of iron and manganese attained in P. warreni do vary depending on the site from
which animals are collected. From this, it is suggested that these crustaceans be
incorporated into biomonitoring protocols, particularly in areas that are
subjected to elevated metal levels in the environment
PMID- 9756710
TI - Fungal avirulence genes: structure and possible functions.
AB - Avirulence (Avr) genes exist in many fungi that share a gene-for-gene
relationship with their host plant. They represent unique genetic determinants
that prevent fungi from causing disease on plants that possess matching
resistance (R) genes. Interaction between elicitors (primary or secondary
products of Avr genes) and host receptors in resistant plants causes induction of
various defense responses often involving a hypersensitive response. Avr genes
have been successfully isolated by reverse genetics and positional cloning. Five
cultivar-specific Avr genes (Avr4, Avr9, and Ecp2 from Cladosporium fulvum; nip1
from Rhynchosporium secalis; and Avr2-YAMO from Magnaporthe grisea) and three
species-specific Avr genes (PWL1 and PWL2 from M. grisea and inf1 from
Phytophthora infestans) have been cloned. Isolation of additional Avr genes from
these fungi, but also from other fungi such as Uromyces vignae, Melampsora lini,
Phytophthora sojae, and Leptosphaeria maculans, is in progress. Molecular
analyses of nonfunctional Avr gene alleles show that these originate from
deletions or mutations in the open reading frame or the promoter sequence of an
Avr gene. Although intrinsic biological functions of most Avr gene products are
still unknown, recent studies have shown that two Avr genes, nip1 and Ecp2,
encode products that are important pathogenicity factors. All fungal Avr genes
cloned so far have been demonstrated or predicted to encode extracellular
proteins. Current studies focus on unraveling the mechanisms of perception of
avirulence factors by plant receptors. The exploitation of Avr genes and the
matching R genes in engineered resistance is also discussed.
PMID- 9756711
TI - Phylogeny of the genus trichoderma based on sequence analysis of the internal
transcribed spacer region 1 of the rDNA cluster
AB - Sequences of the internal transcribed spacer region 1 (ITS1) of the ribosomal DNA
were used to determine the phylogenetic relationships of species of Trichoderma
sect. Pachybasium. To this end, 85 strains-including all the available ex-type
strains-were analyzed. Parsimony analysis demonstrated that the section is
nonmonophyletic, distributing the 85 strains among three main groups that were
supported by bootstrap values. Group A comprises two clades (A1 and A2), with A1
including T. polysporum, T. piluliferum, and T. minutisporum, while A2 included
T. hamatum, T. pubescens, and T. strigosum in addition to species previously
included in sect. Trichoderma (i.e., T. viride, T. atroviride, and T. koningii).
The ex-type strain of T. fasciculatum formed a separate branch basal to clade A.
Clade B contained the sect. Pachybasium members T. harzianum, T. fertile, T.
croceum, T. longipile, T. strictipile, T. tomentosum, T. oblongisporum, T.
flavofuscum, T. spirale, and the anamorphs of Hypocrea semiorbis and H. cf.
gelatinosa. Sequence differences among clades A1, A2, and B were in the same
order of magnitude as between each of them and T. longibrachiatum, which was used
as an outgroup in these analyses. Sequence differences within clades A1, A2, and
B were considerably smaller: in some cases (i.e., T. virens and T. flavofuscum;
T. strictipile and H. cf. gelatinosa), the ITS1-sequences were identical,
suggesting conspecifity. In other cases (e.g., T. crassum and T. longipile; T.
harzianum, T. inhamatum, T. croceum, T. fertile, and H. semiorbis; T. hamatum and
T. pubescens; and T. viride, T. atroviride, and T. koningii) differences were in
the range of 1-3 nt only, suggesting a very close phylogenetic relationship. The
sequence of a previously described aggressive mushroom competitor group of T.
harzianum strains (Th2) was strikingly different from that of the ex-type strain
of T. harzianum and closely related species and is likely to be a separate
species. Copyright 1998 Academic Press.
PMID- 9756712
TI - Regulation of hsp90 and hsp70 genes during antheridiol-induced hyphal branching
in the oomycete Achlya ambisexualis.
AB - When mycelia of Achlya ambisexualis J. Raper strain E87 were undergoing
antheridial branching, a marked increase was observed in the levels of transcript
populations encoding the heat shock protein chaperone Hsp90 and transcript
populations encoding three different Hsp70-family heat shock protein chaperones,
respectively. Although up to 90% of hyphae in the hormone-treated thalli were
undergoing antheridial branching, no similar increase in the level of transcripts
encoding actin was observed. Nuclear run-on assays demonstrated that the observed
antheridiol-induced increases in the levels of the chaperone RNAs resulted from
increased transcription. Although not tested for function, the nucleotide
sequence of the 5' flanking region of each of the two A. ambisexualis hsp90 genes
revealed a diversity of sequences and motifs similar or identical to the
sequences of known transcription factor response elements. Among these potential
response element sequences observed in the A. ambisexualis genes were motifs
observed also in animal steroid hormone response elements. Surrounding the primer
extension determined transcription start site of each A. ambisexualis hsp90 gene
was a 16-nucleotide sequence that matched in 14 out of 16 nucleotides a sequence
found in the transcription initiation region of many different oomycete genes.
PMID- 9756714
TI - In vivo addition of telomeric repeats to foreign DNA generates extrachromosomal
DNAs in the taxol-producing fungus Pestalotiopsis microspora.
AB - Transformation of the taxol-producing filamentous fungus Pestalotiopsis
microspora with a plasmid containing the bacterial hygromycin resistance gene
fused to Aspergillus regulatory sequences resulted in the in vivo formation of
extrachromosomal DNAs with telomeric repeats in the majority of transformants.
Repeats of the telomeric sequence 5'-TTAGGG-3' were appended to nontelomeric
transforming DNA termini. No fungal sequences other than telomeric repeats were
detected in extrachromosomal DNAs. Transformants contained three to six different
sizes or conformational forms of extrachromosomal DNAs. The DNAs showed no change
in size or internal structure during 6 months of growth with selection, but were
lost after 20 days of growth without selection. Transformation of wild-type P.
microspora with a PCR-amplified extrachromosomal DNA having terminal telomeric
repeats produced up to 50-fold more transformants than the original
transformation vector. The addition of telomeric repeats to foreign DNA is
unusual among fungi and may have important adaptive or developmental
implications.
PMID- 9756713
TI - Relationships of the insect-pathogenic order Entomophthorales (Zygomycota, Fungi)
based on phylogenetic analyses of nuclear small subunit ribosomal DNA sequences
(SSU rDNA).
AB - We sequenced the nuclear small subunit of ribosomal DNA (SSU rDNA) from seven
species within the insect-pathogenic order Entomophthorales. These sequences were
aligned with other published SSU rDNA sequences and phylogenies were inferred
using phenetic and cladistic methods. Based on three different phylogenetic
methods the Entomophthorales (excluding Basidiobolus ranarum) is monophyletic; B.
ranarum was more closely related to chytrids from Chytridiales and
Neocallimasticales than to Entomophthorales, as was proposed by Nagahama et al.
(Mycologia 87: 203-209, 1995). Nuclear characters (large nuclei containing
conspicuous condensed chromatin and lack of a prominent nucleolus) were of
predictive value for the monophyly of the family Entomophthoraceae. Conidial
characters separate the Entomophthoraceae, which only includes obligate
pathogens, into at least two lineages: one lineage with uninucleate conidia and
another with multinucleate conidia. The two species of Conidiobolus studied were
paraphyletic in our analyses and only distantly related to each other. This
information may prove to be important in the use of these fungi as biocontrol
agents.
PMID- 9756715
TI - A cell-free translation-translocation system reconstituted with subcellular
fractions from the wall-less variant fz;sg;os-1V of Neurospora crassa.
AB - A translation-translocation system reconstituted with subcellular fractions from
the wall-less variant fz;sg;os-1V of Neurospora crassa reproduces in vitro
translocation and processing of a secretory protein. The translation extract was
isolated from the wall-less variant by gently lysing cells by a freeze-thaw
procedure. This method yielded more extract then the method developed previously
(R. Addison, J. Biol. Chem. 262: 17031, 1987) as well as reducing microsomal
contamination. The microsomal fraction was isolated from lysed cells using a
series of discontinuous sucrose gradients. The resultant microsomes were less
inhibitory to translation of various transcripts and consisted of a more
homogenous mixture of vesicles then microsomes prepared previously. Polyclonal
antibodies directed against a polypeptide of approximately 75 kDa from the
microsomes were used in indirect-immunofluorescence microscopy. The resultant
fluorescent pattern shows a network of tubulo-reticular structures in a
juxtanuclear region, which is the pattern expected of the rough endoplasmic
reticulum.
PMID- 9756716
TI - Evolution of spore release mechanisms in the saprolegniaceae (Oomycetes):
evidence from a phylogenetic analysis of internal transcribed spacer sequences
AB - Classical studies on spore release within the Saprolegniaceae (Oomycetes) led to
the proposition that different mechanisms of sporangial emptying represent steps
in an evolutionary transition series. We have reevaluated this idea in a
phylogenetic framework using internal transcribed spacer sequences of four
genera. These data were compared with the response to osmotic stress exhibited by
each taxon. Saprolegnia emerges as the most basal genus, sister to Achlya,
Thraustotheca, and Dictyuchus. Achlya and Thraustotheca are most closely related,
while Dictyuchus appears to have evolved along a separate evolutionary lineage.
The resulting phylogenetic framework is consistent with the idea that the
mechanism of sporangial emptying exhibited by Saprolegnia represents the
plesiomorphic condition from which the other mechanisms were derived
independently. These alternative mechanisms of spore release may have resulted
from a small number of mutations that inhibited axonemal development and altered
the temporal and spatial expression of lytic enzymes that degrade the sporangial
wall. Copyright 1998 Academic Press.
PMID- 9756717
TI - Characterization and molecular genetic complementation of mutants affecting
dimorphism in the fungus ustilago maydis
AB - Ustilago maydis, the causal agent of corn smut disease, displays dimorphic growth
in which it alternates between a unicellular, nonpathogenic yeast-like form and a
dikaryotic, pathogenic filamentous form. Previously, a constitutively filamentous
haploid mutant was obtained. Complementation of this mutant led to the isolation
of the gene encoding adenylate cyclase, uac1. Secondary mutagenesis of a uac1
disruption strain allowed the isolation of a large number of suppressor mutants,
termed ubc, for Ustilago bypass of cyclase, lacking the filamentous phenotype.
Analysis of one of these suppressor mutants previously led to the identification
of the ubc1 gene, encoding the regulatory subunit of cAMP-dependent protein
kinase. In this report we describe the isolation of cosmids containing three new
ubc genes, termed ubc2, ubc3, and ubc4. We also describe the morphology of the
ubc2, ubc3, and ubc4 mutants in a uac1- background as well as in a background
with a functional uac1 gene. In addition, we describe several mutant strains not
complemented with any of the genes currently in hand and that are thus presumed
to possess mutations in additional ubc genes. Copyright 1998 Academic Press.
PMID- 9756718
TI - New opportunities for the treatment of severe autoimmune diseases: bone marrow
transplantation.
PMID- 9756719
TI - Proposed CD4(+) T-cell criteria for staging human immunodeficiency virus-infected
Chinese adults.
AB - The present treatment, prophylaxis, and prognostic staging of human
immunodeficiency virus (HIV) disease rely heavily on peripheral CD4(+) T
lymphocyte (CD4) changes. We correlated the clinical course of events and CD4
changes among consecutive HIV-infected ethnic Chinese adults in Hong Kong. Using
death as end point, the estimated proportion survival and death incidences were
used to compare CDC and proposed staging criteria based on stratified baseline
CD4. A separate set of baseline CD4 per microliter (/microl) (percentage
lymphocytes) stratification criteria of 1, >220/microl (>12%); 2, 100-220/microl
(6-12%); and 3, <100/microl, (<6%) is proposed which can be used for staging HIV
infected Chinese adults. For our study population, our proposed criteria for
stratifying baseline CD4 gave better discrimination and more predictive power
than the CDC criteria. We assessed the potential impact of these new proposed
criteria on anti-retroviral treatment and prophylaxis against opportunistic
infections in our adult HIV-infected population.
PMID- 9756720
TI - Circulating Toxoplasma gondii-specific antibody-secreting cells in patients with
congenital toxoplasmosis.
AB - Patients with congenital toxoplasmosis occasionally show rises in serum
antibodies to Toxoplasma gondii (serological rebound), but the underlying cause
remains unclear. The acute or chronic presence of available antigen often causes
the appearance, in the peripheral blood, of cells actively secreting specific
antibody. We have evaluated the capacity of circulating blood cells from 91
children born to T. gondii-infected mothers to actively synthesize anti-T. gondii
antibodies according to their serological status. Supernatants from 7-day
cultures of peripheral blood mononuclear cells were evaluated for antibody by
cytofluorimetry. Only 1 of 49 subjects with low and stable serum antibody titers
produced specific antibodies on cultures, while 9 of 22 subjects with recent
rebound were positive. One of the positive children alone showed clinical signs
of parasite activity. These observations suggest that rebound may be associated
with production of available parasite antigens, possibly associated with
reactivation. Differentiation from other causes, such as polyclonal B cell
stimulation, would improve our ability to detect clinically significant
reactivation and to prevent complications.
PMID- 9756721
TI - The expression and localization of fibroblast growth factor-1 (FGF-1) and FGF
receptor-1 (FGFR-1) in human breast cancer.
AB - Fibroblast growth factor-1 (FGF-1) is an inducer of angiogenesis, the growth of
new blood vessels. The expression and localization of FGF-1 (acidic FGF) and FGF
receptor (FGFR)-1 in mammary tissues from patients with breast cancer was
investigated using Western blot analysis and immunohistochemistry. The affinity
purified FGF-1 antibody which did not have cross-reactivity to FGF-2 (basic FGF)
was used in this study. Western blot analysis demonstrated the presence of FGF-1
protein in all of the samples from breast cancer, but not benign tumors such as
mastopathy and fibroadenoma. To assess the localization of FGF-1 in cancer
tissues, immunostaining with specific antibody was performed. All samples from
breast cancer displayed significantly intense staining with FGF-1 antibody. The
extent and intensity of immunoreactive FGF-1 polypeptides in cancer cells was
statistically much greater than those of cells from fibroadenoma or mastopathy.
Control immunostaining with normal rabbit serum or anti-FGF-1 antibody adsorbed
with the recombinant FGF-1 polypeptide was completely negative. In contrast to
FGF-1, Western blot analysis demonstrated the presence of FGFR-1 protein in all
of the samples from breast cancer and benign tumors. By immunohistochemical
analysis, the enhanced expression of FGFR-1 was observed in breast cancer cells.
Benign tumor cells or interstitial cells displayed a faint expression of FGFR-1.
These results demonstrated that breast cancer cells not only generated FGF-1, but
also expressed FGFR-1, and FGF-1 might play a role in the proliferation of breast
cancer cells not only by paracrine but also by autocrine mechanism.
PMID- 9756722
TI - Determination of primary amino acid sequence and unique three-dimensional
structure of WGH1, a monoclonal human IgM antibody with anti-PR3 specificity.
AB - Transformed B cells making monoclonal IgM-lambda anti-PR3 antibody WGH1 from a
patient with Wegener's granulomatosis were used to prepare mRNA and synthesize
cDNA. PCR primers for human micro and lambda chains were then employed to amplify
heavy- and light-chain V-regions followed by cloning into pCR2-1 vector and
sequencing. Molecular modeling of VH regions employed knowledge-based homology
modeling to obtain minimum energy conformation. The VH sequence was subgroup III
with marked overall homology to VH1.9III. The VHCDR3 region of WGH1 was unique,
consisting of 21 amino acid residues which included seven tyrosines as well as
three negatively charged aspartic acid residues. The VL region was subgroup II
with a negatively charged glutamic acid at position 100 in CDR3. Molecular
modeling of VH revealed a major conformational difference in the shape of CDR3
compared with other antibodies for which three-dimensional structures have been
determined. Monoclonal antibody WGH1 reacting with PR3 (a highly positively
charged molecule) shows a unique reactive cassette within VHCDR3 with a number of
negatively charged aspartic acid residues. WGH1 VHCDR3 contains a loop which
shows a major projection not usually recorded in other previously studied
antibody molecules.
PMID- 9756724
TI - Adhesion molecules in tissue injury: kinetics of expression and shedding and
association with cytokine release in humans.
AB - Adhesion molecules are responsible for leukocyte recruitment in injured tissues.
Here, the kinetics of expression and shedding of endothelial (sE-selectin-1, sP
selectin, and sICAM-1) and neutrophil (CD11b, CD62L, and CD54) adhesion molecules
was investigated by serial determinations of serum concentrations in 20 patients
with elective hip arthroplasty as an exemplary condition of acute inflammation in
humans. Changes were related to secretion of proinflammatory cytokines (IL-1beta,
IL-6, IL-8, and TNF-alpha) as their possible inducing signals. sE-selectin-1
responded to injury with a significant increase in concentrations already after
20 min, followed by sP-selectin and sICAM-1, which increased at Hour 10 and Day
1. Expression of CD11b and CD62L acutely responded to injury (within 1 h) by a
parallel increase and decrease, respectively, and normalized by Day 1. Increases
in concentrations of IL-1beta and TNF-alpha preceded the increase in adhesion
molecules and significantly correlated with the response of sE-selectin-1 and
sICAM-1. In conclusion, the close associations between release of IL-1beta and
TNF-alpha and sE-selectin and sICAM-1 shown in this kinetic study indicates a key
role of these cytokines in upregulation of endothelial rather than neutrophil
adhesion molecules in vivo.
PMID- 9756723
TI - RANTES expression and contribution to monocyte chemotaxis in arthritis.
AB - Rheumatoid arthritis (RA) is characterized by recruitment of leukocytes from the
vasculature into inflamed synovial tissue (ST) and synovial fluid (SF), which
depends, in part, upon the continued maintenance of chemotactic stimuli. RANTES
is a potent chemoattractant for leukocytes including monocytes and CD45RO+ memory
T lymphocytes. The aim of this study was to determine the production, the source,
and the function of antigenic RANTES in arthritis. We detected antigenic RANTES
in SFs from RA and OA patients (100 +/- 22.7 and 72 +/- 30.7 pg/ml,
respectively). CM from RA ST fibroblasts stimulated with interleukin-1beta or
tumor necrosis factor-alpha contained significantly more antigenic RANTES than
unstimulated CM (452 +/- 181.6 and 581 +/- 200.2 pg/ml, respectively, versus 12
+/- 4.4 pg/ml, P < 0.05). PHA-stimulated RA SF mononuclear cells secreted 5- to
15-fold more antigenic RANTES than did nonstimulated mononuclear cells, while LPS
induced secretion up to 4-fold. We immunolocalized antigenic RANTES to sublining
macrophages (28 +/- 3.7 and 8 +/- 2.0% immunopositive cells), perivascular
macrophages (56 +/- 6.9 and 19 +/- 3.4%), and synovial lining cells (37 +/- 5.8
and 60 +/- 10.4%) in RA and OA tissue, respectively. Anti-RANTES neutralized 20.2
+/- 1.3% of the RA SF chemotactic activity for normal peripheral blood monocytes
(P < 0.05). These results demonstrate antigenic RANTES in RA and OA ST and SF and
identify RANTES as a chemoattractant for monocytes in the RA joint.
PMID- 9756725
TI - Age-related persistent clonal expansions of CD28(-) cells: phenotypic and
molecular TCR analysis reveals both CD4(+) and CD4(+)CD8(+) cells with identical
CDR3 sequences.
AB - In a small group of subjects we had identified persistent expansions (range 6
72%) of CD4(+)CD8(+) double-positive (DP) peripheral blood (PB) cells which
express the CD8 alpha/alpha homodimer. Here, DP cells present in a larger cohort
were further investigated and found by FACS analysis to express a single or a
dominant TCRBV family. In these subjects, with a mean age of about 64 years,
expansions of CD4(+) cells with the same TCRBV family specificity as in the
respective DP cells also were consistently detected. TCR heterogeneity of the
dominant TCRBV family was specifically evaluated: The amplified CDR3 region was
cloned and found to consist of one single or two largely dominant sequence
patterns. Furthermore, cloning of the CDR3 region from FACS-sorted DP, CD4(+), or
CD8(+) cells indicates that both DP and CD4(+), but not CD8(+) cells, isolated
from the same individual possess a striking identity of the CDR3 regions. As
indicated by FACS analysis, the clonally expanded cells occur in the CD4(+)CD28(
) cells. Taken together, these results suggest that expanded CD4(+)CD28(-) cells
might also acquire CD8 alpha/alpha expression and become DP and imply that CD4
clonality is a more frequent phenomenon than previously suspected. In conclusion,
the persistent expansions described in this report represent a novel group of age
related benign clonal expansions of still undefined significance of a rare CD28(
) T cell subset.
PMID- 9756726
TI - Analysis of autoantibodies against RNA polymerases using immunoaffinity-purifed
RNA polymerase I, II, and III antigen in an enzyme-linked immunosorbent assay.
AB - Autoantibodies against RNA polymerases (RNAP) have been reported to occur in
patients with a wide variety of connective tissue diseases (CTD), including
systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and mixed
connective tissue disease (MCTD). The frequency of anti-RNAP antibodies has been
reported to vary widely between different CTD diseases in studies examining
different patient populations. Furthermore, these studies have been limited by
the fact that methods have not previously been available for detecting antibodies
against RNAP which are both rapid and quantitative. We have developed an enzyme
linked immunosorbent assay (ELISA) for rapidly quantitating antibodies against
RNAP I, II, and III. We have utilized both the ELISA and the immunoprecipitation
of 35S-labeled HeLa cells to analyze sera from a large cohort of well
characterized Caucasian CTD patients for the presence of anti-RNAP antibodies. We
found excellent concordance for the presence of anti-RNAP antibodies using
immunoprecipitation and ELISA. Anti-RNAP antibodies occurred predominantly among
female patients with the diffuse form of SSc and were detected in 8/36 (22%) of
Caucasian patients with diffuse SSc and 1/53 (2%) with limited SSc. Anti-RNAP
antibodies occurred in 1/42 (2%) of patients with SLE. Anti-RNAP antibodies did
not occur in MCTD (0/49). Antibodies against RNAP were rare among antinucleolar
reactive sera, occurring in only 3/200 (1.5%). The RNAP ELISA provides a
validated method which can be rapidly utilized in a clinical diagnostic
laboratory setting to identify SSc patients who are at risk for developing
diffuse SSc with multiorgan involvement and hypertensive renal crisis.
PMID- 9756727
TI - CD44 variant isoform expression in a variety of skin-associated autoimmune
diseases.
AB - CD44 variant isoforms are frequently expressed on tissue-infiltrating
lymphocytes. By the high incidence of autoimmune reactions of the skin and aiming
at new strategies of therapeutic intervention, we became interested in evaluating
the CD44 isoform expression profile in autoimmune reactions of the skin.
Expression of CD44s, CD44v3, v5, v6, v7, v7-v8, and v10 was evaluated in 55
biopsies of lupus erythematosus, bullous pemphigoid, vasculitis, morphea, and
pemphigus vulgaris. Biopsies did not contain CD44v5-, CD44v6-, CD44v7-, or CD44v7
v8-positive leukocytes. Staining with anti-CD44v10 was seen in vasculitis and
occasionally in lupus erythematosus, morphea, and bullous pemphigoid. All
biopsies contained CD44v3(+) leukocytes, the percentage of CD44v3(+) leukocytes
being increased in autoimmune infiltrates with the exception of pemphigus
vulgaris. CD44v3 was expressed by CD4(+) cells as well as by part of CD8(+)
cells, Langerhans cells, and monocytes. Vascular endothelium also contained
CD44v3(+) cells. Only monocytes expressed CD44v10. We assume that CD44v3 and
CD44v10 may be targeting leukocytes toward the skin or allow for their retention
and expansion via binding of cytokines and chemokines harbored by activated, skin
associated endothelium or provided by cells surrounding the infiltrate. The
absence of CD44v6, frequently associated with lymphocyte activation, appears to
be a peculiarity of skin-infiltrating leukocytes.
PMID- 9756728
TI - Soluble proteins isolated from Borrelia burgdorferi by extraction with Triton X
114 confer resistance to experimental infection.
AB - Fractionation of Borrelia burgdorferi was made by extraction of infectious
spirochetes using the detergent Triton X-114. Gel electrophoresis analysis of
hydrophilic and hydrophobic proteins demonstrated that detergent extraction
resulted in two populations of proteins with nonoverlapping electrophoretic
profiles. Immunoblot analysis with monoclonal antibodies reactive with two
abundant membrane proteins demonstrated that hydrophilic proteins were
uncontaminated with hydrophobic proteins. In addition, assay of thymidine
incorporation into and secretion of tumor necrosis factor-alpha from splenocytes
cocultured in vitro with either detergent or aqueous phase proteins showed that
lymphocyte mitogenic and macrophage activation activities of B. burgdorferi were
completely absent from the hydrophilic phase proteins. The Triton X-114 aqueous
and detergent phase proteins were used to immunize BALB/c and separately
microMT/microMT (B cell knockout) mice that were subsequently challenged with
infectious B. burgdorferi. The hydrophilic phase proteins were able to induce
protective resistance to infection in either strain of mice demonstrating that
potential candidate vaccine antigens are contained in the biochemical class of
antigens which is devoid of both lymphocyte mitogen activity and major outer
surface proteins. Furthermore, the ability to vaccinate B cell knockout mice
suggests that the humoral antispirochete immune response is not the exclusive
basis for protective immunity.
PMID- 9756729
TI - Serological association of measles virus and human herpesvirus-6 with brain
autoantibodies in autism.
AB - Considering an autoimmunity and autism connection, brain autoantibodies to myelin
basic protein (anti-MBP) and neuron-axon filament protein (anti-NAFP) have been
found in autistic children. In this current study, we examined associations
between virus serology and autoantibody by simultaneous analysis of measles virus
antibody (measles-IgG), human herpesvirus-6 antibody (HHV-6-IgG), anti-MBP, and
anti-NAFP. We found that measles-IgG and HHV-6-IgG titers were moderately higher
in autistic children but they did not significantly differ from normal controls.
Moreover, we found that a vast majority of virus serology-positive autistic sera
was also positive for brain autoantibody: (i) 90% of measles-IgG-positive
autistic sera was also positive for anti-MBP; (ii) 73% of measles-IgG-positive
autistic sera was also positive for anti-NAFP; (iii) 84% of HHV-6-IgG-positive
autistic sera was also positive for anti-MBP; and (iv) 72% of HHV-6-IgG-positive
autistic sera was also positive for anti-NAFP. This study is the first to report
an association between virus serology and brain autoantibody in autism; it
supports the hypothesis that a virus-induced autoimmune response may play a
causal role in autism.
PMID- 9756730
TI - Effects of endotoxin on lung pericytes in vitro.
AB - Lipopolysaccharide released during bacterial sepsis causes acute lung injury and
ARDS. Pulmonary microvascular injury is a feature of ARDS, and vascular
remodeling develops, leading to pulmonary hypertension. Pericytes in the lung
circulation proliferate and contribute to the remodeling seen in experimental
sepsis. It is unknown whether endotoxin can directly stimulate pericyte growth or
induce contraction. We show that lipopolysaccharide from Escherichia coli,
Pseudomonas aeruginosa, and Klebsiella pneumoniae increases rat lung pericyte
proliferation in vitro by up to 72% on day 7 of exposure (P < 0.001), with E.
coli being most potent. Lipid A is the active portion of the lipopolysaccharide,
with equal activity at one-tenth the dose of lipopolysaccharide. Endotoxin's
mitogenic effect requires the presence of serum, consistent with the requirement
for a soluble CD14 receptor in the serum. Using FACS analysis, the pericytes lack
surface CD14 receptors. Lipopolysaccharide exposure rapidly increases
intracellular calcium and induces contraction of pericytes plated onto silicone
membranes. Thus, endotoxin is a direct mitogen for lung pericytes in vitro and
also induces pericyte contraction. Endotoxin, present in lung tissue early during
sepsis, might directly contribute to the vascular remodeling in sepsis-induced
lung injury.
PMID- 9756731
TI - Capillary density and leukocyte adhesion in hamsters with hereditary
cardiomyopathy.
AB - The aim of this study was to characterize microvascular networks in cheek pouch
of cardiomyopathic Syrian hamster (CM) (Bio 14.6), which is an interesting model
of idiopathic cardiomyopathy and congestive heart failure. Microcirculation was
visualized by fluorescence microscopy. Diameter and length of arterioles,
classified according to centrifugal ordering scheme, were measured. A
computational method was arranged to determine the density of arterioles and
capillaries (total vessel length per unit area, cm-1), fractal dimension of
capillaries, and the associated Voronoi tesselation. Furthermore, leukocyte
adhesion to venules and arteriolar reactivity to drugs were studied. Increase in
the number of terminal arterioles and capillary rarefication characterized CM
microvasculature compared with that of age-matched controls (58 +/- 7 versus 25
+/- 5 cm-1, and 128 +/- 15 versus 240 +/- 10 cm-1, respectively). Fractal
dimension of capillaries was reduced in CM compared with controls (1. 40 +/- 0.10
versus 1.85 +/- 0.09) and associated with increased avascular spaces, as shown by
Voronoi tesselation results. Leukocyte adhesion to venules increased
significantly in CM. In CM responsiveness of arterioles to nitric oxide
inhibition and propranolol was slighter but more marked to norepinephrine and
angiotensin II compared with that of control hamsters. In conclusion, the
different geometry, increased leukocyte adhesion, and altered arterial
responsiveness may contribute to flow disturbances in the microcirculation of CM
hamsters.
PMID- 9756732
TI - Effect of acute coronary occlusion on the size of the dynamically perfused
coronary capillary bed in the dog.
AB - The aim of the present study was to investigate the influence of reduced left
anterior descending (LAD) coronary arterial blood flow on the size of the
perfused coronary capillary surface area (CCSA) in dogs. The transcoronary
hydrolysis (v) of the specific ACE substrate, [3H]benzoyl-Phe-Ala-Pro, was
estimated and the parameter Amax/Km (proportional to the size of the perfused
CCSA) was calculated. By means of a ligature placed around the LAD, LAD blood
flow was transiently reduced to 36.0 +/- 4.1 (E1) and 17.4 +/- 4.3% (E2) of
control; in a separate maneuver the first diagonal branch of the LAD was ligated
to achieve 40.0 +/- 6.7% (E3) of control flow. The v values remained unchanged at
around 0.7 for E1, E2, and E3 determinations, suggesting unaltered substrate
transit time through the coronary capillary bed. Amax/Km values decreased to 36
+/- 5, 17 +/- 4, and 47 +/- 10% of control for E1, E2, and E3 determinations,
respectively, reflecting a flow-proportional decrease in CCSA. Values of the
transpulmonary measures of v and Amax/Km performed at the beginning and end of
the protocol were unchanged. These results support the hypothesis that reduction
in coronary blood flow will produce proportional decreases in the size of the
CCSA. This new procedure can thus serve as a useful tool for investigating
alterations in the size of the CCSA in different species and under various
pathophysiologic challenges.
PMID- 9756733
TI - Dynamic changes in intracapillary hemoglobin oxygenation in human skin following
various temperature changes.
AB - To evaluate microvascular regulation in human skin, changes in intracapillary
hemoglobin oxygen saturation (HbO2) were studied in human finger skin following
an abrupt change in local ambient temperature. In the first series of
experiments, we assessed the heterogeneity of HbO2 in the skin by using a 2-D
scanning system and a rapid micro-lightguide spectrophotometer at each of two
near-normal skin temperatures. The data showed that heterogeneous oxygenation
exists in human skin even at near-normal temperatures (although the pattern is
different at different skin temperatures). In a second series of experiments, the
performance of the microcirculation of the skin was continuously examined in a
selected area with initially different oxygenation levels during an abrupt change
in local ambient temperature (5, 15, 25, 35, and 45 degrees C). At very low (5
degrees C) or very high (45 degrees C) temperatures, oxygenation in tissues
within the low HbO2 area increased greatly, but there was no such change within
the high HbO2 area. Our data indicate that different types of capillary supply
units exist in human skin (indicated by the initially different oxygenation
levels). These different capillary supply units may operate to produce a local
redistribution of flow between the various capillary supply units. This effect
may be initiated by heat sensors and oxygen sensors when temperature of the skin
is varied.
PMID- 9756734
TI - Prediction of microcirculatory oxygen transport by erythrocyte/hemoglobin
solution mixtures.
AB - A mathematical model has been developed to predict oxygen transport by
erythrocyte/acellular hemoglobin solution mixtures flowing in arteriolar-sized
vessels (20 to 100 micron diameter). The model includes erythrocyte and
extracellular hemoglobin solution phases, radial hematocrit and velocity
gradients, axial convection, and radial diffusion of both oxygen and
oxyhemoglobin. Model simulations were compared with experimental data from an in
vitro capillary model where all of the geometric, physical, and transport
parameters are known accurately. A new approach to shear augmentation of
transport in 25-micron-diameter conduits was developed. Comparison of theory with
experiment suggests that shear augmentation in this flow regime is primarily an
extracellular phenomenon produced by cell-cell interactions. Negligible shear
augmentation was seen in erythrocyte suspensions in plasma due to the relatively
low solubility of oxygen in the plasma phase. Good agreement was found between
the theoretical simulations and experimental data for release experiments even
neglecting shear augmentation. However, treatment of shear augmentation
significantly improved agreement between theoretical simulations and experimental
data for oxygen uptake. The model was used to determine the effects on oxygen
transport of varying extracellular hemoglobin concentration and extracellular
hemoglobin oxygen binding characteristics. It is known that hemoglobin solutions
transport oxygen more efficiently than erythrocyte suspensions of the same
overall hemoglobin content. Model simulations show that erythrocyte/hemoglobin
solution mixtures with 30% extracellular hemoglobin transport oxygen with
virtually the same efficiency as pure hemoglobin solutions of the same overall
hemoglobin content. Additional simulations predict that erythrocyte/hemoglobin
solution mixtures transport oxygen more efficiently than Rbc suspensions, even if
the extracellular hemoglobin has a high oxygen affinity.
PMID- 9756735
TI - Pressure-volume relationships in sheep mesenteric lymphatic vessels in situ:
response to hypovolemia.
AB - We applied the principles of cardiac mechanics to study the contraction cycles of
postnodal sheep mesenteric lymphatic vessels in an in situ preparation. A segment
of intestinal lymphatic was isolated from lymph input and provided with Krebs
solution from a reservoir. Pressure-volume relationships were assessed under
various transmural pressure conditions using videomicroscopic techniques to
measure diameter changes and a miniature catheter pressure transducer to monitor
intralymphangion pressure. The contraction cycles were quite variable but, on
average, exhibited three phases of systole and three phases of diastole with
periods of isovolumetric contraction and relaxation. Elevations of transmural
pressure up to 4 cm H2O resulted in significant increases in stroke volume,
ejection fraction, pulse pressure, and output/minute but not contraction
frequency. Regression analysis of the end systolic (ESPVR) and end diastolic
pressure-volume relations (EDPVR) revealed a linear ESPVR (r2 = 0.83 +/- 0.03)
and exponential EDPVR (r2 = 0.83 +/- 0.02), a result that is similar to that
observed in cardiac contraction cycles. Following a 25% whole blood volume bleed
(a stimulus known to enhance lymphatic pumping), significant increases in stroke
volume, ejection fraction, and output/minute were observed up to transmural
pressures of 4 cm H2O. While an index used to assess cardiac contractility (end
systolic elastance-Ees) was not observed to change after the bleed, a shift to
the left of the end-systolic pressure-volume relations compared with the sham
bled group (significant shift of regression lines for ESPVR) suggested that
hemorrhage exerted a positive inotropic effect on mesenteric lymphatics.
PMID- 9756737
TI - Gender and Negotiator Competitiveness: A Meta-analysis.
AB - Although there have been numerous investigations into the relationship between
gender and bargaining competitiveness over the past several decades, few
conclusions have been reached. The results of 62 research reports on the
relationship between gender and competitive behavior in dyadic bargaining
interactions were examined by meta-analytic review. The average weighted effect
size indicated that women appear to behave more cooperatively in negotiations
than men, but this difference is slight. Results suggest that constraints on
negotiators (imposed by abstract bargaining paradigms and restrictions on
communication) lessen gender differences in negotiation behavior. Women were
significantly more competitive than men when competing against an opponent who
pursued a "tit-for-tat" bargaining strategy. Copyright 1998 Academic Press.
PMID- 9756738
TI - Decision Accuracy in Computer-Mediated versus Face-to-Face Decision-Making Teams.
AB - Changes in the way organizations are structured and advances in communication
technologies are two factors that have altered the conditions under which group
decisions are made. Decisions are increasingly made by teams that have a
hierarchical structure and whose members have different areas of expertise. In
addition, many decisions are no longer made via strictly face-to-face
interaction. The present study examines the effects of two modes of communication
(face-to-face or computer-mediated) on the accuracy of teams' decisions. The
teams are characterized by a hierarchical structure and their members differ in
expertise consistent with the framework outlined in the Multilevel Theory of team
decision making presented by Hollenbeck, Ilgen, Sego, Hedlund, Major, and
Phillips (1995). Sixty-four four-person teams worked for 3 h on a computer
simulation interacting either face-to-face (FtF) or over a computer network. The
communication mode had mixed effects on team processes in that members of FtF
teams were better informed and made recommendations that were more predictive of
the correct team decision, but leaders of CM teams were better able to
differentiate staff members on the quality of their decisions. Controlling for
the negative impact of FtF communication on staff member differentiation
increased the beneficial effect of the FtF mode on overall decision making
accuracy. Copyright 1998 Academic Press.
PMID- 9756736
TI - Direct relaxing effect of estradiol-17beta and progesterone on rat saphenous
artery.
AB - Although estrogen has been reported to relax large coronary arteries immediately,
its direct acute effect on small vessel tone has not been fully defined. In this
study, we investigated the effect of estradiol-17beta and progesterone on
isolated rat saphenous artery segments-with an internal radius of 250 microm-by
measuring the outer diameter of the vessels using in vitro angiometry. Estradiol
and progesterone at concentrations of 1-100 and 8.6-86 microM induced a rapid,
dose-dependent relaxation of the arterial segments precontracted with
norepinephrine. Maximal changes of diameters were 85.8 +/- 10 and 90.9 +/- 8%.
Clomiphene citrate, a cytoplasmic receptor antagonist, did not diminish this
action of estradiol, with the exception of the highest concentrations of the
hormone. Thus a nongenomic pathway for this effect can be suspected.
Dexamethasone did not induce similar vasodilation. It is concluded that estradiol
and progesterone have similar rapid vasorelaxing effects on small muscular
arteries as found previously on coronary arteries.
PMID- 9756739
TI - Effect of Regret on Post-choice Valuation: The Case of More Than Two
Alternatives.
AB - The author examines the influence of experienced regret on the selection of the
reference point used in post-choice valuation. He incorporates two reference
points, expected performance and performance of the forgone alternative, the
former affecting the amount of satisfaction and the latter affecting the amount
of regret experienced by a decision maker. Prior research on regret has assumed
only a two-alternative choice set with the forgone alternative being the
reference point for measuring regret. The author relaxes that assumption and
develops hypotheses to examine the selection of the reference point in cases that
more closely represent real-life experience (i.e., choice sets with more than two
alternatives). Two studies are reported. The results from the first study support
most of the hypotheses. The second study further investigated the selection of a
reference point. Several theoretical and managerial implications are discussed
and future research directions are suggested. Copyright 1998 Academic Press.
PMID- 9756740
TI - Resource-Allocation Strategies: A Verbal Protocol Analysis.
AB - The current study examined the strategies used by people to solve resource
allocation problems. Verbal protocols were recorded as participants provided meal
choices for seven consecutive days with limited resources available to spend on
meals and with daily constraints imposed on meal consumption. None of the
participants incorporated the established mathematical procedures (i.e., Linear
Programming) to arrive at the optimum number of meals possible in a week.
However, the strategies they did use enabled them to achieve meal totals on
average at 94% of this optimal amount. A few participants attempted to first
solve the maximum meals possible in a week before scheduling this solution across
the seven days (solve-and-schedule strategy), but the majority of participants
simply selected meals on a day-to-day basis while checking resource availability
each day to allow for full resource consumption (consume-and-check strategy). The
findings of this study provide a preliminary step toward understanding how people
make intuitive resource-allocation decisions. Copyright 1998 Academic Press.
PMID- 9756741
TI - Renaturation of recombinant human neurotrophin-3 from inclusion bodies using a
suppressor agent of aggregation.
AB - Escherichia coli has been widely used in the production of recombinant proteins.
One of the drawbacks inherent in this method is that the proteins produced in the
cells often form inactive inclusion bodies. Usually, the inclusion bodies can be
separated from other cell components, solubilized by denaturants such as
guanidine hydrochloride or urea, and then renatured through a refolding process
such as dilution or dialysis. However, it has been shown that biologically active
recombinant human neurotrophin-3 cannot be obtained at high yield by this
procedure due to aggregation and precipitation of the protein. We applied the
refolding process using the aggregation suppressor L-arginine in the renaturation
of neurotrophin-3, and obtained biologically active neurotrophin-3 at high yield
from the inclusion bodies. Consequently, about 10 mg of purified neurotrophin-3
was prepared from 1 litre of culture broth.
PMID- 9756742
TI - Recombinant human mast cell tryptase beta: stable expression in Pichia pastoris
and purification of fully active enzyme.
AB - Human mast cell tryptase beta (EC 3.4.21.59) is a trypsin-like serine protease
that is stored in and released from mast cell granules. This enzyme has been
expressed in Pichia pastoris via homologous recombination of the cDNA coding for
the mature active tryptase with the addition of a KEX 2 processing site into the
Pichia genome. Cells producing recombinant human tryptase (rHT) were selected by
screening with antibodies. Induction with methanol resulted in the secretion of
rHT into the Pichia growth medium; tryptase activity was stabilized by the
addition of heparin to the culture medium. Increasing levels of enzyme were
detected in the medium for up to 3 days. Fully active enzyme was purified from
the culture medium with a 100% yield of activity via a simple two-step procedure,
with hydrophobic interaction chromatography followed by affinity chromatography
on immobilized heparin. Bands of 33 (faint), 34.2, 35.9 and 50 kDa (diffuse) were
observed on SDS/PAGE. These multiple forms were due to differences in post
translational glycosylation of asparagine residues, because enzymic
deglycosylation resulted in only one band at 33 kDa. A single symmetrical peak
with an estimated size of 197 kDa was obtained on gel filtration. Kinetic
analyses in comparison with native human lung mast cell tryptase (HLT) yielded
similar Km values, but the kcat of rHT was more than twice that of HLT.
PMID- 9756743
TI - Granulocyte colony-stimulating factor and azole antifungal therapy in murine
aspergillosis: role of immune suppression.
AB - Outbred ICR mice were immune suppressed either with hydrocortisone or with 5
fluorouracil and were infected intranasally with Aspergillus fumigatus. Beginning
3 days before infection some groups of mice were given recombinant human
granulocyte colony-stimulating factor (G-CSF), SCH56592 (an antifungal triazole),
or both. Corticosteroid-pretreated mice responded to SCH56592 and had reduced
counts in lung tissue and prolonged survival. In these mice, G-CSF strongly
antagonized the antifungal activity of SCH56592. Animals treated with both agents
developed large lung abscesses with polymorphonuclear leukocytes and large
amounts of Aspergillus. In contrast, mice made neutropenic with 5-fluorouracil
and then infected with A. fumigatus conidia benefited from either G-CSF or
triazoles, and the effect of the combination was additive rather than
antagonistic. Host predisposing factors contribute in different ways to the
outcome of growth factor therapy in aspergillosis.
PMID- 9756744
TI - Sequencing of gyrase and topoisomerase IV quinolone-resistance-determining
regions of Chlamydia trachomatis and characterization of quinolone-resistant
mutants obtained In vitro.
AB - The L2 reference strain of Chlamydia trachomatis was exposed to subinhibitory
concentrations of ofloxacin (0.5 microg/ml) and sparfloxacin (0.015 microg/ml) to
select fluoroquinolone-resistant mutants. In this study, two resistant strains
were isolated after four rounds of selection. The C. trachomatis mutants
presented with high-level resistance to various fluoroquinolones, particularly to
sparfloxacin, for which a 1,000-fold increase in the MICs for the mutant strains
compared to the MIC for the susceptible strain was found. The MICs of unrelated
antibiotics (doxycycline and erythromycin) for the mutant strains were identical
to those for the reference strain. The gyrase (gyrA, gyrB) and topoisomerase IV
(parC, parE) genes of the susceptible and resistant strains of C. trachomatis
were partially sequenced. A point mutation was found in the gyrA quinolone
resistance-determining region (QRDR) of both resistant strains, leading to a
Ser83-->Ile substitution (Escherichia coli numbering) in the corresponding
protein. The gyrB, parC, and parE QRDRs of the resistant strains were identical
to those of the reference strain. These results suggest that in C. trachomatis,
DNA gyrase is the primary target of ofloxacin and sparfloxacin.
PMID- 9756745
TI - Restoration of immune response by a cationic amphiphilic drug (AY 9944) in vitro:
a new approach To chemotherapy against human immunodeficiency virus type 1.
AB - AY 9944 [AY; trans-1,4-bis(chlorobenzylaminomethyl)-cyclohexane dihydrochloride],
an inhibitor of sterol synthesis, was found to help restore the normal mitogenic
responses and cytokine profiles of peripheral mononuclear cells (PBMCs) from AIDS
patients in vitro. Compared to untreated cells, the human immunodeficiency virus
type 1 (HIV-1)-infected PBMCs precultured in the presence of AY exhibited a
normal rate of either mitogen-induced or recall- and superantigen-induced
proliferation. After 2 weeks in the presence of the drug, the percentage of dead
CD4(+) cells in HIV-1-infected cultures was comparable to that observed in
uninfected cultures, while over the same time interval it increased by three- to
fivefold in HIV-1-infected cultures maintained in the absence of AY. AY also
stimulated by 2- to 12-fold interleukin-12 (IL-12) and (gamma interferon
production. For IL-12, this effect appears to be related to an increase in
corresponding IL-12 p35 and IL-12 p40 mRNA levels. Moreover, AY restored the
expression of the IL-2 receptor, which was severely impaired in HIV-1-infected
PBMCs. Although the drug has no direct antiviral effect (it does not
significantly inhibit reverse transcriptase activity measured in vitro), it might
be considered a potential therapeutic agent for HIV-infected patients, in that it
may correct viral infection-related immune system defects by indirectly enhancing
the level of resistance to HIV and opportunistic infections.
PMID- 9756746
TI - Mucoadhesive microspheres containing amoxicillin for clearance of Helicobacter
pylori.
AB - In an effort to augment the anti-Helicobacter pylori effect of amoxicillin,
mucoadhesive microspheres, which have the ability to reside in the
gastrointestinal tract for an extended period, were prepared. The microspheres
contained the antimicrobial agent and an adhesive polymer (carboxyvinyl polymer)
powder dispersed in waxy hydrogenated castor oil. The percentage of amoxicillin
remaining in the stomach both 2 and 4 h after oral administration of the
mucoadhesive microspheres to Mongolian gerbils under fed conditions was about
three times higher than that after administration in the form of a 0.5%
methylcellulose suspension. The in vivo clearance of H. pylori following oral
administration of the mucoadhesive microspheres and the 0.5% methylcellulose
suspension to infected Mongolian gerbils was examined under fed conditions. The
mucoadhesive microspheres and the 0.5% methylcellulose suspension both showed
anti-H. pylori effects in this experimental model of infection, but the required
dose of amoxicillin was effectively reduced by a factor of 10 when the
mucoadhesive microspheres were used. In conclusion, the mucoadhesive microspheres
more effectively cleared H. pylori from the gastrointestinal tract than the 0.5%
methylcellulose suspension due to the prolonged gastrointestinal residence time
resulting from mucoadhesion. A dosage form consisting of mucoadhesive
microspheres containing an appropriate antimicrobial agent should be useful for
the eradication of H. pylori.
PMID- 9756747
TI - Structure-in vitro activity relationships of pentamidine analogues and dication
substituted bis-benzimidazoles as new antifungal agents.
AB - Twenty analogues of pentamidine, 7 primary metabolites of pentamidine, and 30
dicationic substituted bis-benzimidazoles were screened for their inhibitory and
fungicidal activities against Candida albicans and Cryptococcus neoformans. A
majority of the compounds had MICs at which 80% of the strains were inhibited
(MIC80s) comparable to those of amphotericin B and fluconazole. Unlike
fluconazole, many of these compounds were found to have potent fungicidal
activity. The most potent compound against C. albicans had an MIC80 of =0.09
microg/ml, and the most potent compound against C. neoformans had an MIC80 of
0.19 microg/ml. Selected compounds were also found to be active against
Aspergillus fumigatus, Fusarium solani, Candida species other than C. albicans,
and fluconazole-resistant strains of C. albicans and C. neoformans. It is clear
from the data presented here that further studies on the structure-activity
relationships, mechanisms of action and toxicities, and in vivo efficacies of
these compounds are warranted to determine their clinical potential.
PMID- 9756748
TI - In vitro antifungal activities of a series of dication-substituted carbazoles,
furans, and benzimidazoles.
AB - Aromatic dicationic compounds possess antimicrobial activity against a wide range
of eucaryotic pathogens, and in the present study an examination of the
structures-functions of a series of compounds against fungi was performed. Sixty
seven dicationic molecules were screened for their inhibitory and fungicidal
activities against Candida albicans and Cryptococcus neoformans. The MICs of a
large number of compounds were comparable to those of the standard antifungal
drugs amphotericin B and fluconazole. Unlike fluconazole, potent inhibitory
compounds in this series were found to have excellent fungicidal activities. The
MIC of one of the most potent compounds against C. albicans was 0.39 microg/ml,
and it was the most potent compound against C. neoformans (MIC, =0.09
microg/ml). Selected compounds were also found to be active against Aspergillus
fumigatus, Fusarium solani, Candida species other than C. albicans, and
fluconazole-resistant strains of C. albicans and C. neoformans. Since some of
these compounds have been safely given to animals, these classes of molecules
have the potential to be developed as antifungal agents.
PMID- 9756749
TI - Intracellular delivery and antibacterial activity of gentamicin encapsulated in
pH-sensitive liposomes.
AB - Cell membranes are relatively impermeable to the antibiotic gentamicin, a factor
that, along with the toxicity of gentamicin, precludes its use against many
important intracellular bacterial infections. Liposomal encapsulation of this
drug was used in order to achieve intracellular antibiotic delivery and therefore
increase the drug's therapeutic activity against intracellular pathogens.
Gentamicin encapsulation in several dipalmitoylphosphatidylcholine (DPPC) and pH
sensitive dioleoylphosphatidylethanolamine (DOPE)-based carrier systems was
characterized. To systematically test the antibacterial efficacies of these
formulations, a tissue culture assay system was developed wherein murine
macrophage-like J774A.1 cells were infected with bacteria and were then treated
with encapsulated drug. Of these formulations, DOPE-N-succinyl-DOPE and DOPE-N
glutaryl-DOPE (70:30;mol:mol) containing small amounts of polyethyleneglycol
ceramide showed appreciable antibacterial activities, killing greater than 75% of
intracellular vacuole-resident wild-type Salmonella typhimurium compared to the
level of killing of the control formulations. These formulations also efficiently
eliminated intracellular infections caused by a recombinant hemolysin-expressing
S. typhimurium strain and a Listeria monocytogenes strain, both of which escape
the vacuole and reside in the cytoplasm. Control non-pH-sensitive liposomal
formulations of gentamicin had poor antibacterial activities. A fluorescence
resonance energy transfer assay indicated that the efficacious formulations
undergo a pH-dependent lipid mixing and fusion event. Intracellular delivery of
the fluorescent molecules encapsulated in these formulations was confirmed by
confocal fluorescence microscopy and was shown to be dependent on endosomal
acidification. This work shows that encapsulation of membrane-impermeative
antibiotics in appropriately designed lipid-based delivery systems can enable
their use in treating intracellular infections and details the development of a
general assay for testing the intracellular delivery of encapsulated drug
formulations.
PMID- 9756750
TI - Interaction of Streptococcus pneumoniae and Moraxella catarrhalis: investigation
of the indirect pathogenic role of beta-lactamase-producing moraxellae by use of
a continuous-culture biofilm system.
AB - The majority of clinical isolates of Moraxella catarrhalis produce beta
lactamase. The role of this enzyme in the phenomenon of indirect pathogenicity,
in which a true pathogen such as Streptococcus pneumoniae is protected from the
action of certain beta-lactam antibiotics, is well recognized. By using a simple
continuous-culture biofilm system, it has been shown that the pneumococcus
attains high titers in excess of 10(12) CFU/biofilm; furthermore, the penicillin
sensitive pneumococcus used remained susceptible to a range of beta-lactam
antibiotics in these biofilms (R. K. Budhani and J. K. Struthers, J. Antimicrob.
Chemother. 40:601-602, 1997). This system was used to characterize the antibiotic
susceptibility of this isolate when grown with beta-lactamase-negative or
positive moraxellae. When grown with beta-lactamase-producing moraxellae in the
presence of either benzylpenicillin or amoxicillin, the pneumococcus was
protected in the range of the antibiotic concentrations to which it would be
considered resistant. With amoxicillin-clavulanic acid the titers of the two
organisms collapsed at the antibiotic concentration at which moraxellae became
susceptible. The levels of beta-lactamase activity in cell-free supernatants of
broth culture, in biofilm, and in biofilm effluent revealed distinct differences
in this activity; levels in biofilm were significantly lower than those in broth
culture supernatants. The system appears suitable for studying organisms under
antibiotic stress and for investigating the interactions of bacteria under such
conditions.
PMID- 9756751
TI - Reduction by cefodizime of the pulmonary inflammatory response induced by heat
killed Streptococcus pneumoniae in mice.
AB - It has recently become apparent that overwhelming inflammatory reactions
contribute to the high mortality rate associated with pneumococcal infection in
immunocompetent hosts. Cefodizime (CEF) is an antibiotic that seems to be endowed
with immunomodulating properties. To investigate the influence of CEF on the
pulmonary inflammatory response induced by Streptococcus pneumoniae, we infected
mice with repeated intranasal inoculations of 10(7) CFU of heat-killed
fluorescein isothiocyanate-labeled bacteria, which are insensitive to the killing
properties of the drug. CEF downregulated but did not abolish the strong
polymorphonuclear leukocyte (PMN) recruitment induced by S. pneumoniae. PMN
recruitment was not primarily mediated by leukotriene B4 in this model. The drug
did not interfere with intrinsic mechanisms of phagocytosis by PMNs and alveolar
macrophages. CEF totally abrogated the pneumococcus-induced tumor necrosis factor
alpha (TNF-alpha) and interleukin-6 (IL-6) secretion in bronchoalveolar lavage
fluid. The drug also prevented IL-6 release in lung homogenates and partly
inhibited TNF-alpha, but it did not interfere with IL-1alpha secretion in the
lungs of infected mice. The fractional and selective downregulation of
inflammatory cells and cytokines by CEF suggests cell-specific and intracellular
specific mechanisms of interaction of the drug. The immunomodulatory properties
of CEF may help restrain excessive inflammatory reactions, thus contributing to
the reported good clinical efficacy of the drug against lower respiratory tract
infections.
PMID- 9756752
TI - Identification and characterization of novel antimicrobial decapeptides generated
by combinatorial chemistry.
AB - Novel combinatorial libraries consisting of simplified amino acid sequences were
designed to screen for peptides active against the Candida albicans membrane. A
novel decapeptide, KKVVFKVKFK, that had a unique primary amino acid sequence was
identified in this work. This peptide irreversibly inhibited the growth of C.
albicans and showed a broad range of antibacterial activity but no hemolytic
activity. Circular dichroism spectra revealed that the predominant secondary
structure of this peptide strongly depended on the membrane-mimetic environments;
the peptide preferred to form an amphipathic alpha-helical structure in the
presence of 50% trifluoroethanol, while it preferred to adopt a distorted alpha
helical structure in the presence of sodium dodecyl sulfate micelles. Experiments
in which dye was released from vesicles indicated that this novel antimicrobial
peptide killed microorganisms through the action on the membrane as its primary
target. Replacement of amino acids in this active decapeptide on the basis of
information from the libraries could provide unique information about factors
affecting its antimicrobial activity such as its secondary structure, net
positive charge, and hydrophobicity.
PMID- 9756753
TI - Efficacies of KY62 against Leishmania amazonensis and Leishmania donovani in
experimental murine cutaneous leishmaniasis and visceral leishmaniasis.
AB - Current therapy for leishmaniasis is unsatisfactory because parenteral antimonial
salts and pentamidine are associated with significant toxicity and failure rates.
We examined the efficacy of KY62, a new, water-soluble, polyene antifungal,
against cutaneous infection with Leishmania amazonensis and against visceral
infection with Leishmania donovani in susceptible BALB/c mice. Mice were infected
with L. amazonensis promastigotes in the ear pinna and in the tail and were
treated with KY62 or amphotericin B. The cutaneous lesions showed a remarkable
response to therapy with KY62 at a dose of 30 mg per kg of body weight per day.
At this dose, the efficacy of KY62 was equivalent to or better than that of
amphotericin B at 1 to 5 mg/kg/day. Mice infected intravenously with 10(7) L.
donovani promastigotes and treated with KY62 showed a 4-log reduction in the
parasite burden in the liver and spleen compared to untreated mice. These studies
indicate potent activity of KY62 against experimental cutaneous leishmaniasis
caused by L. amazoniensis and against experimental visceral leishmaniasis caused
by L. donovani.
PMID- 9756755
TI - Characterization of In40 of Enterobacter aerogenes BM2688, a class 1 integron
with two new gene cassettes, cmlA2 and qacF.
AB - Enterobacter aerogenes BM2688, which is resistant to multiple antibiotics, and
its aminoglycoside-susceptible derivative BM2688-1 were isolated from the same
clinical sample. Strain BM2688 harbored plasmid pIP833, which carries a class 1
integron, In40, containing (in addition to qacEDelta1 and sul1, which are
characteristic of class 1 integrons) four gene cassettes: aac(6')-Ib, qacF,
cmlA2, and oxa-9. The cmlA2 gene had 83.7% identity with the previously described
nonenzymatic chloramphenicol resistance cmlA1 gene. The qacF gene conferred
resistance to quaternary ammonium compounds and displayed a high degree of
similarity with qacE (67.8% identity) which, however, has been found as part of a
cassette with a very different 59-base element. The oxa-9 gene was not expressed
due to a lack of promoter sequences. Study of the antibiotic-susceptible
derivative BM2688-1 indicated that a 3,148-bp deletion between the 3' end of the
aac(6')-Ib gene and the 3' conserved segment of In40 was responsible for the loss
of resistance. The occurrence of this DNA rearrangement, which did not involve
homologous sequences, suggests that the In40 integrase could promote
recombination at secondary sites.
PMID- 9756754
TI - Interleukin-12 enhances in vivo parasiticidal effect of benznidazole during acute
experimental infection with a naturally drug-resistant strain of Trypanosoma
cruzi.
AB - The roles of gamma interferon (IFN-gamma) and interleukin-12 (IL-12) in mediating
and/or enhancing the in vivo trypanosomicidal activity of the nitroheterocyclic
derivative benznidazole (Bz) were evaluated during early stages of experimental
Chagas' disease. Our results show that treatment of Trypanosoma cruzi-infected
mice with anti-cytokine monoclonal antibodies (MAbs) had no apparent effect when
the optimal dose of Bz (100 mg/kg of body weight) was used. In contrast,
treatment with anti-IL-12 or anti-IFN-gamma MAbs enhanced the parasitemia and
accelerated the mortality of mice treated with a suboptimal dose of Bz (25
mg/kg). Simultaneous treatment with a suboptimal dose of Bz and recombinant IL-12
(rIL-12) enhanced the efficacy of drug treatment in terms of parasitemia and
mouse survival. Interestingly, we found that drug-resistant T. cruzi strains were
found to be poor inducers of IL-12 both in vitro and in vivo compared to strains
of T. cruzi which are susceptible or partially resistant to Bz treatment. These
results suggest that early activation of the cellular compartment of the immune
system by IL-12 may favor in vivo Bz activity against T. cruzi. In order to test
this hypothesis mice infected with the drug-resistant Colombiana strain of T.
cruzi were treated with 100 mg of Bz per kg plus different concentrations of rIL
12. By using the results of PCR and serological and parasitological methods as
the criteria of a cure, our results indicate that a higher percentage of mice
treated with Bz combined with rIL-12 than mice treated with Bz alone are cured.
PMID- 9756756
TI - Comparison of inhibitory and bactericidal activities and postantibiotic effects
of LY333328 and ampicillin used singly and in combination against vancomycin
resistant Enterococcus faecium.
AB - One hundred ninety-five individual vancomycin-resistant Enterococcus faecium
(VRE) isolates from five upstate New York hospitals were studied for
antimicrobial susceptibilities to LY333328, quinupristin-dalfopristin,
teicoplanin, ampicillin, and gentamicin. LY333328 was the most active antibiotic
against VRE. The effect of media and methods on the antibacterial activity of
LY333328, its synergy with ampicillin, and the postantibiotic effects (PAE) of
LY333328 and ampicillin were evaluated. In microdilution tests, the MIC of
LY333328 at which 90% of the isolates were inhibited (MIC90) was 2 microg/ml in
Mueller-Hinton II (MH II) broth and 1 microg/ml in brain heart infusion (BHI)
broth. In contrast, on MH II agar the MIC90 was 4 microg/ml and on BHI agar it
was >16 microg/ml. Bactericidal activity was observed for most strains at
concentrations from 8 to >/=133 times the MIC of the tube macrodilution in MH II
broth. A bactericidal effect of LY333328 plus ampicillin was demonstrated in time
kill studies, but there was great strain-to-strain variability. By the MH II agar
dilution method, bacteristatic synergy (defined as a fractional inhibitory
concentration of <0.5) with LY333328 and ampicillin was demonstrated for 61% of
the strains tested. Under similar conditions, there was synergy with LY333328 and
quinupristin-dalfopristin or gentamicin for 27 and 15% of the strains tested,
respectively. The PAE of LY333328 was prolonged (23.0 h at 10 times the MIC).
However, 50% normal pooled human serum decreased the PAE to 12.2 h at 10 times
the MIC. Test conditions and media had a considerable effect on VRE
susceptibilities to LY333328. The prolonged PAE of LY333328, a potent new
bactericidal glycopeptide, and its synergy with ampicillin in a large proportion
of strains suggest that further evaluation of this drug in pharmacokinetic
studies and experimental infections, including those with VRE, is warranted.
PMID- 9756757
TI - Accumulation of amphotericin B in human macrophages enhances activity against
Aspergillus fumigatus conidia: quantification of conidial kill at the single-cell
level.
AB - A cytofluorometric assay that allowed assessment of damage to phagocytosed
Aspergillus fumigatus conidia at the single-cell level was developed. After
ingestion by monocyte-derived macrophages (MDMs), conidia were reisolated by
treatment of the cells with streptolysin O, a pore-forming toxin with lytic
properties on mammalian cells but not on fungi. The counts obtained by staining
of damaged conidia with propidium iodide and quantification by cytofluorometry
correlated with colony counts. By the use of this method, we demonstrate that
MDMs differentiated in vitro by low-dose granulocyte-macrophage colony
stimulating factor and gamma interferon have only a limited capacity to damage
Aspergillus conidia in vitro. The killing rate 12 h after phagocytosis was found
to be only 10 to 15%. However, intracellular loading of the phagocytes with
amphotericin B (AmB) dose dependently enhanced the anticonidial activity.
Preincubation of macrophages with only 1 microg of AmB per ml resulted in an
uptake of 18 fg of AmB/cell, leading to killing rates of 50 to 60%. The
experimental protocol provides a new tool for the rapid quantification of
anticonidial activity against A. fumigatus in vitro. Intracellular accumulation
of AmB may represent an important factor underlying the efficacy of this
antifungal drug in the prophylaxis and treatment of Aspergillus infections.
PMID- 9756758
TI - Roles of amino acids 161 to 179 in the PSE-4 omega loop in substrate specificity
and in resistance to ceftazidime.
AB - The PSE-4 enzyme is a prototype carbenicillin-hydrolyzing enzyme exhibiting high
activity against penicillins and early cephalosporins. To understand the
mechanism that modulates substrate profiles and to verify the ability of PSE-4 to
extend its substrate specificity toward expanded-spectrum cephalosporins, we used
random replacement mutagenesis to generate six random libraries from amino acids
162 to 179 in the Omega loop. This region is known from studies with TEM-1 to be
implicated in substrate specificity. It was found that the mechanism modulating
ceftazidime hydrolysis in PSE-4 was different from that in TEM-1. The specificity
of class 2c carbenicillin-hydrolyzing enzymes could not be assigned to the Omega
loop of PSE-4. Analysis of the percentage of functional enzymes revealed that the
hydrolysis of ampicillin was more affected than hydrolysis of carbenicillin by
amino acid substitutions at positions 162 to 164 and 165 to 167.
PMID- 9756759
TI - Rapid, transient fluconazole resistance in Candida albicans is associated with
increased mRNA levels of CDR.
AB - Fluconazole-resistant Candida albicans, a cause of recurrent oropharyngeal
candidiasis in patients with human immunodeficiency virus infection, has recently
emerged as a cause of candidiasis in patients receiving cancer chemotherapy and
marrow transplantation (MT). In this study, we performed detailed molecular
analyses of a series of C. albicans isolates from an MT patient who developed
disseminated candidiasis caused by an azole-resistant strain 2 weeks after
initiation of fluconazole prophylaxis (K. A. Marr, T. C. White, J. A. H.
vanBurik, and R. A. Bowden, Clin. Infect. Dis. 25:908-910, 1997). DNA sequence
analysis of the gene (ERG11) for the azole target enzyme, lanosterol demethylase,
revealed no difference between sensitive and resistant isolates. A sterol
biosynthesis assay revealed no difference in sterol intermediates between the
sensitive and resistant isolates. Northern blotting, performed to quantify mRNA
levels of genes encoding enzymes in the ergosterol biosynthesis pathway (ERG7,
ERG9, and ERG11) and genes encoding efflux pumps (MDR1, ABC1, YCF, and CDR),
revealed that azole resistance in this series is associated with increased mRNA
levels for members of the ATP binding cassette (ABC) transporter superfamily, CDR
genes. Serial growth of resistant isolates in azole-free media resulted in an
increased susceptibility to azole drugs and corresponding decreased mRNA levels
for the CDR genes. These results suggest that C. albicans can become transiently
resistant to azole drugs rapidly after exposure to fluconazole, in association
with increased expression of ABC transporter efflux pumps.
PMID- 9756760
TI - Characterization of mutations in the rpoB gene that confer rifampin resistance in
Staphylococcus aureus.
AB - Mutations in the rifampin resistance-determining (Rif) regions of the rpoB gene
of Staphylococcus aureus mutants obtained during therapy or in vitro were
analyzed by gene amplification and sequencing. Each of the resistant clinical
isolates, including five nonrelated clones and two strains isolated from the same
patient, and of the 10 in vitro mutants had a single base pair change that
resulted in an amino acid substitution in the beta subunit of RNA polymerase.
Eight mutational changes at seven positions were found in cluster I of the
central Rif region. Certain substitutions (His481/Tyr and Asp471/Tyr [S. aureus
coordinates]) were present in several mutants. Substitutions Gln468/Arg,
His481/Tyr, and Arg484/His, which conferred high-level rifampin resistance, were
identical or in the same codon as those described in other bacterial genera,
whereas Asp550/Gly has not been reported previously. Substitutions at codon 477
conferred high- or low-level resistance, depending on the nature of the new amino
acid. The levels of resistance of in vivo and one-step in vitro mutants carrying
identical mutations were similar, suggesting that no other resistance mechanism
was present in the clinical isolates. On the basis of these data and the
population distribution of more than 4,000 clinical S. aureus isolates, we
propose =0.5 and >/=8 microg/ml as new breakpoints for the clinical
categorization of this species relative to rifampin.
PMID- 9756762
TI - Stability of cephalosporin prodrug esters in human intestinal juice: implications
for oral bioavailability.
AB - The levels of degradation of cefetamet pivoxil (CAT), cefuroxime axetil (CAE),
and cefpodoxime proxetil (CPD) in 0.6 M phosphate buffer (pH 7.4) and human
intestinal juice (pH 7.4) at 37 degreesC over 24 h were compared. Significant
differences in the time courses of degradation and in the patterns of degradation
products were observed. (i) The relative proportions of the Delta2- and Delta3
cephalosporins were roughly reversed in the two incubation media. In phosphate
buffer, the major degradation product was the Delta2-cephalosporin (CAT = 61%;
CAE = 74%; CPD = 85%), while in intestinal juice it was the Delta3-cephalosporin
(CAT = 86%; CAE = 75%; CPD = 87%). (ii) Generally, the degradation of the prodrug
esters progressed faster in intestinal juice than in phosphate buffer (e.g., for
CAT the half-lives [t1/2s] were 0.78 and 4.3 h, respectively). (iii) The two
diastereoisomers of CAE and CPD were degraded at different rates in intestinal
juice (for the CAE diasteroisomers, t1/2s = 0.37 and 0.93 h; for the CPD
diastereoisomers, t1/2s = 0.18 and 0.98 h) but were degraded at similar rates in
phosphate buffer (for the CAE diastereoisomers, t1/2 = 1.6 h; for the CPD t1/2
diastereoisomers, = 2.2 h). It is concluded that (i) the Delta2 isomerization
does not significantly affect the bioavailability of prodrug esters since
enzymatic hydrolysis in the intestinal fluid proceeds mainly to the active Delta3
cephalosporin and (ii) the high degree of stereoselectivity of the enzymatic
ester hydrolysis should make it possible to increase the bioavailabilities of
certain prodrug esters (CAE, CPD) by using the more stable diasterioisomer.
PMID- 9756761
TI - Targeted antimicrobial photochemotherapy.
AB - This study explores a new approach for antimicrobial therapy with light
activation of targeted poly-L-lysine (pL)-chlorin e6 (ce6) conjugates. The goal
was to test the hypothesis that these conjugates between pL and ce6 would
efficiently target photodestruction towards gram-positive (Actinomyces viscosus)
and gram-negative (Porphyromonas gingivalis) oral species while sparing an oral
epithelial cell line (HCPC-1). Conjugates of ce6 with pL (average molecular
weight, 2,000) having a positive, neutral, or negative charge were prepared.
Illumination with red light (lambdamax = 671 nm) from a diode array produced a
dose-dependent loss of CFU from the bacteria, under conditions that did not
affect the viability of the epithelial cells. For P. gingivalis, the cationic
conjugate produced 99% killing, while the neutral conjugate killed 91% and the
anionic conjugate killed 76% after 1 min of incubation and exposure to red light
for 10 min. For A. viscosus, the cationic conjugate produced >99.99% killing
while HCPC-1 cells remained intact. The importance of the positive charge was
shown by the effectiveness of ce6-monoethylenediamine monoamide (a monocationic
derivative of ce6) in killing both bacteria. The clinically employed
benzoporphyrin derivative under the same conditions killed epithelial cells while
leaving P. gingivalis relatively unharmed. A mixture of ce6 with pL did not show
phototoxicity comparable with that of the cationic conjugate. These results were
explained by the selective uptake of the conjugates by bacteria (20- to 100-fold)
compared to that by mammalian cells, while free ce6 showed much less selectivity
for bacteria (5- to 20-fold). The data suggest that the cationic pL-ce6 conjugate
may have an application for the photodynamic therapy of periodontal disease.
PMID- 9756763
TI - Secretion of sparfloxacin from the human intestinal Caco-2 cell line is altered
by P-glycoprotein inhibitors.
AB - The mechanism of intestinal secretion of the difluorinated quinolone sparfloxacin
was investigated with the epithelial cell line Caco-2 and was compared to that of
the P-glycoprotein (P-gp) substrate vinblastine. The P-gp inhibitors verapamil
and progesterone significantly increased the epithelial cell accumulation of both
vinblastine and sparfloxacin. This increase is likely to result from an
inhibition of drug secretion since both vinblastine uptake and sparfloxacin
uptake are known to proceed through a passive transmembrane diffusion. The
unidirectional fluxes across cell monlayers grown on permeable filters indicated
that a net secretion of sparfloxacin and vinblastine occurred across Caco-2
cells. These secretions were significantly inhibited by the MDR-reversing agent
verapamil. We conclude that the P-gp is likely to be involved in the intestinal
elimination of the difluorinated quinolone sparfloxacin.
PMID- 9756764
TI - Characterization of a glycosyl transferase inactivating macrolides, encoded by
gimA from Streptomyces ambofaciens.
AB - In Streptomyces ambofaciens, the producer of the macrolide antibiotic spiramycin,
an open reading frame (ORF) was found downstream of srmA, a gene conferring
resistance to spiramycin. The deduced product of this ORF had high degrees of
similarity to Streptomyces lividans glycosyl transferase, which inactivates
macrolides, and this ORF was called gimA. The cloned gimA gene was expressed in a
susceptible host mutant of S. lividans devoid of any background macrolide
inactivating glycosyl transferase activity. In the presence of UDP-glucose, cell
extracts from this strain could inactivate various macrolides by glycosylation.
Spiramycin was not inactivated but forocidin, a spiramycin precursor, was
modified. In vivo studies showed that gimA could confer low levels of resistance
to some macrolides. The spectrum of this resistance differs from the one
conferred by a rRNA monomethylase, such as SrmA. In S. ambofaciens, gimA was
inactivated by gene replacement, without any deleterious effect on the survival
of the strain, even under spiramycin-producing conditions. But the overexpression
of gimA led to a marked decrease in spiramycin production. Studies with extracts
from wild-type and gimA-null mutant strains revealed the existence of another
macrolide-inactivating glycosyl transferase activity with a different substrate
specificity. This activity might compensate for the effect of gimA inactivation.
PMID- 9756765
TI - An Escherichia coli system expressing human deoxyribonucleoside salvage enzymes
for evaluation of potential antiproliferative nucleoside analogs.
AB - Deoxyribonucleoside salvage in animal cells is mainly dependent on two cytosolic
enzymes, thymidine kinase (TK1) and deoxycytidine kinase (dCK), while Escherichia
coli expresses only one type of deoxynucleoside kinase, i.e., TK. A bacterial
whole-cell system based on genetically modified E. coli was developed in which
the relevant bacterial deoxypyrimidine metabolic enzymes were mutated, and the
cDNA for human dCK or TK1 under the control of the lac promoter was introduced.
The TK level in extract from induced bacteria with cDNA for human TK1 was found
to be 20,000-fold higher than that in the parental strain, and for the strain
with human dCK, the enzyme activity was 160-fold higher. The in vivo
incorporation of deoxythymidine (Thd) and deoxycytidine (dCyd) into bacterial DNA
by the two recombinant strains was 20 and 40 times higher, respectively, than
that of the parental cells. A number of nucleoside analogs, including cytosine
arabinoside, 5-fluoro-dCyd, difluoro-dCyd, and several 5-halogenated deoxyuridine
analogs, were tested with the bacterial system, as well as with human T
lymphoblast CEM cells. The results showed a close correlation between the
inhibitory effects of several important cytostatic and antiviral analogs on the
recombinant bacteria and the cellular system. Thus, E. coli expressing human
salvage kinases is a rapid and convenient model system which may complement other
screening methods in drug discovery projects.
PMID- 9756766
TI - Rifampin concentrations in various compartments of the human brain: a novel
method for determining drug levels in the cerebral extracellular space.
AB - Antimicrobial therapy for brain infections is notoriously difficult because of
the limited extent of knowledge about drug penetration into the brain. Therefore,
we determined the penetration of rifampin into various compartments of the human
brain, including the cerebral extracellular space (CES). Patients undergoing
craniotomy for resection of primary brain tumors were given a standard dose of
600 mg of rifampin intravenously before the operation. A microdialysis probe (10
by 0.5 mm) was inserted into the cortex distantly from the resection and was
perfused with two different rifampin solutions. Rifampin concentrations in the
CES were calculated by the no-net-flux method. Intraoperatively, samples were
taken from brain tumor tissue, perifocal tissue, and normal brain tissue in the
case of pole resections. Rifampin concentrations in the various samples were
determined by using a bioassay with Sarcinea lutea. In the various compartments,
rifampin concentrations were highest within tumors (1.37 +/- 1.34 microg/ml; n =
8), followed by the perifocal region (0.62 +/- 0.67 microg/ml; n = 8), the CES
(0.32 +/- 0.11 microg/ml; n = 6), and normal brain tissue (0.29 +/- 0.15
microg/ml; n = 7). Rifampin concentrations in brain tumors do not adequately
reflect concentrations in normal brain tissue or in the CES. Rifampin
concentrations in the CES, as determined by microdialysis, are the most
reproducible, and the least scattered, of the values for all compartments
evaluated. Rifampin concentrations in all compartments exceed the MIC for
staphylococci and streptococci. However, CES concentrations may be below the MICs
for some mycobacterial strains.
PMID- 9756767
TI - In vitro and in vivo efficacy of the triazole TAK-187 against Cryptococcus
neoformans.
AB - Multiple isolates of Cryptococcus neoformans, including those with fluconazole
resistance, were tested to assess the in vitro activity of the new triazole TAK
187. MICs of TAK-187 were at least eightfold lower than those of fluconazole, and
fungicidal concentrations for most isolates were 4 microg/ml or less. TAK-187
also was evaluated as intermittent therapy using two dosages in a rabbit model of
experimental cryptococcal meningitis. Compared to daily treatment with
fluconazole, as little as two doses of TAK-187 given 7 days apart were found to
be effective. Plasma and cerebrospinal fluid TAK-187 concentrations were many
times higher than MICs and fungicidal concentrations. Based upon its therapeutic
efficacy and long half-life in the rabbit model, TAK-187 should be investigated
for intermittent dosing in treatment or suppression of cryptococcal infections in
humans.
PMID- 9756768
TI - Antibiotic susceptibility patterns of Streptococcus pneumoniae in china and
comparison of MICs by agar dilution and E-test methods.
AB - Beta-lactam resistance by Streptococcus pneumoniae is becoming a significant
threat to public health worldwide. However, data concerning antibiotic
susceptibility patterns in China have not been published. In this study, a total
of 79 clinical isolates and 244 nasopharyngeal isolates of S. pneumoniae were
recovered between June and November 1997 in Beijing. The agreement between the
MICs (+/-1 log2 dilution) of penicillin and ceftriaxone obtained by the agar
dilution and E-test methods for the 79 clinical strains was very good (97.5 and
93.7%, respectively). Of these 79 strains, 9 (11.4%) were intermediate and 2
(2.5%) were resistant to penicillin. Of the 244 nasopharyngeal strains, 32
(13.1%) were intermediate and 3 (1. 2%) were resistant to penicillin. The total
of 277 penicillin-susceptible clinical and nasopharyngeal isolates of
Streptococcus pneumoniae were 100% susceptible to amoxicillin-clavulanic acid,
cefuroxime, ceftriaxone, and cefotaxime. In the 35 penicillin-intermediate and
resistant nasopharyngeal strains, elevated MICs of amoxicillin-clavulanic acid,
cefuroxime, ceftriaxone, and cefotaxime were seen for =4 isolates. Of 244
nasopharyngeal isolates, the overall percentages of tetracycline, erythromycin,
chloramphenicol, ofloxacin, and trimethoprim-sulfamethoxazole resistance were
87.6, 74.0, 47.8, 3.7 and 63.3, respectively. Vancomycin and rifampin resistance
were not detected. These findings demonstrate that the rate of penicillin
resistant pneumococci is relatively low in China compared to those of other Asian
countries. Resistance to non-beta-lactams was much higher than to beta-lactams.
The E-test and agar dilution methods appeared to be comparable in identifying
resistant strains.
PMID- 9756769
TI - Genotypic and phenotypic characterization of human immunodeficiency virus type 1
variants isolated from patients treated with the protease inhibitor nelfinavir.
AB - Nelfinavir mesylate (formerly AG1343) is a potent and selective inhibitor of
human immunodeficiency virus (HIV) protease approved for the treatment of
individuals infected with HIV. Nucleotide sequence analysis of protease genes
from plasma HIV type 1 (HIV-1) RNA revealed a unique aspartic acid (D)-to
asparagine (N) substitution at residue 30 (D30N) in 25 of 55 patients treated
with nelfinavir for a median of 13 weeks. Although the appearance of D30N was
occasionally associated with concurrent or sequential emergence of other changes
(e.g., at residues 35, 36, 46, 71, 77, and 88), genotypic changes associated with
phenotypic resistance to other protease inhibitors were not observed (e.g., at
residues 48, 50, 82, and 84) or were only rarely observed (e.g., at residue 90).
In phenotypic assays, viral isolates with high-level resistance to nelfinavir
remained susceptible to indinavir, saquinavir, ritonavir, and amprenavir
(formerly VX-478/141W94). Similar results were observed in phenotypic assays
utilizing HIV-1 NL4-3, which contained the D30N substitution alone or in
combination with substitutions at other residues (e.g., residues 46, 71, and 88).
These data indicate that the initial pathway of resistance to nelfinavir is
unique and suggest that individuals failing short courses of nelfinavir
containing regimens may respond to regimens containing other protease inhibitors.
PMID- 9756770
TI - Mechanism of fluconazole resistance in Candida krusei.
AB - The mechanisms of fluconazole resistance in three clinical isolates of Candida
krusei were investigated. Analysis of sterols of organisms grown in the absence
and presence of fluconazole demonstrated that the predominant sterol of C. krusei
is ergosterol and that fluconazole inhibits 14alpha-demethylase in this organism.
The 14alpha-demethylase activity in cell extracts of C. krusei was 16- to 46-fold
more resistant to inhibition by fluconazole than was 14alpha-demethylase activity
in cell extracts of two fluconazole-susceptible strains of Candida albicans.
Comparing the carbon monoxide difference spectra of microsomes from C. krusei
with those of microsomes from C. albicans indicated that the total cytochrome P
450 content of C. krusei is similar to that of C. albicans. The Soret absorption
maximum in these spectra was located at 448 nm for C. krusei and at 450 nm for C.
albicans. Finally, the fluconazole accumulation of two of the C. krusei isolates
was similar to if not greater than that of C. albicans. Thus, there are
significant qualitative differences between the 14alpha-demethylase of C.
albicans and C. krusei. In addition, fluconazole resistance in these strains of
C. krusei appears to be mediated predominantly by a reduced susceptibility of
14alpha-demethylase to inhibition by this drug.
PMID- 9756771
TI - Pharmacodynamics of gatifloxacin in cerebrospinal fluid in experimental
cephalosporin-resistant pneumococcal meningitis.
AB - The purpose of this study was to evaluate the cerebrospinal fluid (CSF)
pharmacodynamics of a new fluoroquinolone, gatifloxacin (AM-1155), in
experimental pneumococcal meningitis. The penetration of gatifloxacin into CSF,
calculated as the percentage of the area under the concentration-time curve (AUC)
in CSF over the AUC in blood, was 46 to 56%. Gatifloxacin showed linear
pharmacokinetics in CSF, and 1 h after intravenous dosages of 7.5, 15, or 30
mg/kg of body weight, peak CSF concentrations were 0.46 +/- 0.08 (mean +/-
standard deviation), 0.94 +/- 0.16, and 1.84 +/- 0.5 microg/ml, respectively. The
elimination half-life of gatifloxacin in CSF was 3. 8 to 5.6 h (compared with 2.7
to 3.2 h in blood). There was a significant interrelationship among the highest
measured values of gatifloxacin in blood and CSF/minimal bactericidal
concentration (Cpeak/MBC), the time antibiotic concentrations exceeded the MBC (T
> MBC), and AUC/MBC (r = 0.94); in single-dose experiments, each correlated
significantly with the bacterial killing rate. Divided-dose regimens, resulting
in greater T > MBC values but lower Cpeak/MBC ratios, were more effective in
terms of bacterial clearance compared with corresponding single-dose regimens.
Gatifloxacin therapy was as effective as currently recommended regimens (e.g., a
combination of ceftriaxone and vancomycin) against this highly cephalosporin
resistant pneumococcal strain. The bactericidal activity of gatifloxacin in CSF
was closely related to the AUC/MBC ratio, but maximal activity was achieved only
when drug concentrations exceeded the MBC for the entire dosing interval.
PMID- 9756772
TI - Development of a new cartridge radioimmunoassay for determination of
intracellular levels of lamivudine triphosphate in the peripheral blood
mononuclear cells of human immunodeficiency virus-infected patients.
AB - A new sensitive method for the measurement of lamivudine triphosphate (3TC-TP),
the active intracellular metabolite of lamivudine in human cells in vivo, has
been established. The procedure involves rapid separation of 3TC-TP by using Sep
Pak cartridges, dephosphorylation to 3TC by using acid phosphatase, and
measurement by radioimmunoassay using a newly developed anti-3TC serum. The
radioimmunoassay had errors of less than 21% and a cross-reactivity of less than
0.016% with a wide variety of other nucleoside analogs. The limit of quantitation
of the assay for intracellular 3TC-TP was 0.195 ng/ml (0.212 pmol/10(6) cells),
and a cell sample of only 4 million cells was ample for the assay. This
procedure, combined with our previously developed method for measuring zidovudine
(ZDV) metabolite levels, proved capable of measuring 3TC-TP, ZDV monophosphate
(ZDV-MP) and ZDV triphosphate (ZDV-TP) in human immunodeficiency virus (HIV)
infected subjects treated with combination 3TC and ZDV therapy. In seven
subjects, intracellular 3TC-TP levels ranged from 2.21 to 7.29 pmol/10(6) cells,
while intracellular ZDV-MP and ZDV-TP levels ranged from <0. 01 to 1.76 and 0.01
to 0.07 pmol/10(6) cells, respectively. Concentrations of 3TC in plasma
determined in these subjects ranged from 0.34 to 9.40 microM, which was about
fivefold higher than ZDV levels in plasma of 0.04 to 1.4 microM. This is the
first study to determine the intracellular levels of the active metabolites in
HIV-infected subjects treated with this combination. These methods should prove
very useful for in vivo pharmacodynamic studies of combination therapy.
PMID- 9756773
TI - gyrA mutations associated with fluoroquinolone resistance in eight species of
Enterobacteriaceae.
AB - Fluoroquinolone resistance (FQ-R) in clinical isolates of Enterobacteriaceae
species has been reported with increasing frequency in recent years. Two
mechanisms of FQ-R have been identified in gram-negative organisms: mutations in
DNA gyrase and reduced intracellular drug accumulation. A single point mutation
in gyrA has been shown to reduce susceptibility to fluoroquinolones. To determine
the extent of gyrA mutations associated with FQ-R in enteric bacteria, one set of
oligonucleotide primers was selected from conserved sequences in the flanking
regions of the quinolone resistance-determining regions (QRDR) of Escherichia
coli and Klebsiella pneumoniae. This set of primers was used to amplify and
sequence the QRDRs from 8 Enterobacteriaceae type strains and 60 fluoroquinolone
resistant clinical isolates of Citrobacter freundii, Enterobacter aerogenes,
Enterobacter cloacae, E. coli, K. pneumoniae, Klebsiella oxytoca, Providencia
stuartii, and Serratia marcescens. Although similarity of the nucleotide
sequences of seven species ranged from 80.8 to 93.3%, when compared with that of
E. coli, the amino acid sequences of the gyrA QRDR were highly conserved.
Conservative amino acid substitutions were detected in the QRDRs of the
susceptible type strains of C. freundii, E. aerogenes, K. oxytoca (Ser-83 to
Thr), and P. stuartii (Asp-87 to Glu). Strains with ciprofloxacin MICs of >2
microg/ml expressed amino acid substitutions primarily at the Gly-81, Ser-83, or
Asp-87 position. Fluoroquinolone MICs varied significantly for strains exhibiting
identical gyrA mutations, indicating that alterations outside gyrA contribute to
resistance. The type and position of amino acid alterations also differed among
these six genera. High-level FQ-R frequently was associated with single gyrA
mutations in all species of Enterobacteriaceae in this study except E. coli.
PMID- 9756774
TI - Antiparasitic effects of the intra-Golgi transport inhibitor megalomicin.
AB - The macrolide antibiotic megalomicin (MGM) has been shown to inhibit vesicular
transport between the medial- and trans-Golgi, resulting in the undersialylation
of cellular proteins (P. Bonay, S. Munro, M. Fresno, and B. Alarcon, J. Biol.
Chem. 271:3719-3726, 1996). Due to the effects of MGM on the Golgi and on the
replication of enveloped viruses, we decided to test whether it has any
antiparasitic activity. The results showed that MGM has potent activity against
the epimastigote stage of Trypanosoma cruzi, producing a 50% inhibitory
concentration (IC50) of 0.2 microg/ml. Furthermore, MGM was also active against
the intracellular replicative, amastigote form of T. cruzi, completely preventing
its replication in infected murine LLC/MK2 macrophages at a dose of 5 microg/ml.
Although less potent, MGM was also active against Trypanosoma brucei
epimastigotes (IC50, 2 microg/ml) and Leishmania donovani and Leishmania major
promastigotes (IC50, 3 and 8 microg/ml, respectively). MGM also blocked
intracellular replication of the asexual stage of Plasmodium falciparum-infected
erythrocytes at 1 microg/ml. Finally, MGM was active in an in vivo model,
resulting in the complete protection of BALB/c mice from death caused by acute T.
brucei infection and significantly reducing the parasitemia. These results
suggest that MGM is a potential drug for the treatment of veterinary and human
parasitic diseases.
PMID- 9756775
TI - In vivo efficacy of ABT-255 against drug-sensitive and -resistant Mycobacterium
tuberculosis strains.
AB - Current therapy for pulmonary tuberculosis involves 6 months of treatment with
isoniazid, pyrazinamide, rifampin, and ethambutol or streptomycin for reliable
treatment efficacy. The long treatment period increases the probability of
noncompliance, leading to the generation of multidrug-resistant isolates of
Mycobacterium tuberculosis. A treatment option that significantly shortened the
course of therapy, or a new class of antibacterial effective against drug
resistant M. tuberculosis would be of value. ABT-255 is a novel 2-pyridone
antibacterial agent which demonstrates in vitro potency and in vivo efficacy
against drug-susceptible and drug-resistant M. tuberculosis strains. By the
Alamar blue reduction technique, the MIC of ABT-255 against susceptible strains
of M. tuberculosis ranged from 0.016 to 0.031 microg/ml. The MIC of ABT-255
against rifampin- or ethambutol-resistant M. tuberculosis isolates was 0.031
microg/ml. In a murine model of pulmonary tuberculosis, 4 weeks of oral ABT-255
therapy produced a 2- to 5-log10 reduction in viable drug-susceptible M.
tuberculosis counts from lung tissue. Against drug-resistant strains of M.
tuberculosis, ABT-255 produced a 2- to 3-log10 reduction in viable bacterial
counts from lung tissue. ABT-255 is a promising new antibacterial agent with
activity against M. tuberculosis.
PMID- 9756776
TI - Inhibitory activities of gatifloxacin (AM-1155), a newly developed
fluoroquinolone, against bacterial and mammalian type II topoisomerases.
AB - We determined the inhibitory activities of gatifloxacin against Staphylococcus
aureus topoisomerase IV, Escherichia coli DNA gyrase, and HeLa cell topoisomerase
II and compared them with those of several quinolones. The inhibitory activities
of quinolones against these type II topoisomerases significantly correlated with
their antibacterial activities or cytotoxicities (correlation coefficient [r] =
0.926 for S. aureus, r = 0.972 for E. coli, and r = 0.648 for HeLa cells).
Gatifloxacin possessed potent inhibitory activities against bacterial type II
topoisomerases (50% inhibitory concentration [IC50] = 13.8 microg/ml for S.
aureus topoisomerase IV; IC50 = 0.109 microg/ml for E. coli DNA gyrase) but the
lowest activity against HeLa cell topoisomerase II (IC50 = 265 microg/ml) among
the quinolones tested. There was also a significant correlation between the
inhibitory activities of quinolones against S. aureus topoisomerase IV and those
against E. coli DNA gyrase (r = 0.969). However, the inhibitory activity against
HeLa cell topoisomerase II did not correlate with that against either bacterial
enzyme. The IC50 of gatifloxacin for HeLa cell topoisomerase II was 19 and was
more than 2,400 times higher than that for S. aureus topoisomerase IV and that
for E. coli DNA gyrase. These ratios were higher than those for other quinolones,
indicating that gatifloxacin possesses a higher selectivity for bacterial type II
topoisomerases.
PMID- 9756777
TI - Use of microsphere technology for targeted delivery of rifampin to Mycobacterium
tuberculosis-infected macrophages.
AB - Microsphere technology was used to develop formulations of rifampin for targeted
delivery to host macrophages. These formulations were prepared by using
biocompatible polymeric excipients of lactide and glycolide copolymers. Release
characteristics were examined in vitro and also in two monocytic cell lines, the
murine J774 and the human Mono Mac 6 cell lines. Bioassay assessment of cell
culture supernatants from monocyte cell lines showed release of bioactive
rifampin during a 7-day experimental period. Treatment of Mycobacterium
tuberculosis H37Rv-infected monocyte cell lines with rifampin-loaded microspheres
resulted in a significant decrease in numbers of CFU at 7 days following initial
infection, even though only 8% of the microsphere-loaded rifampin was released.
The levels of rifampin released from microsphere formulations within monocytes
were more effective at reducing M. tuberculosis intracellular growth than
equivalent doses of rifampin given as a free drug. These results demonstrate that
rifampin-loaded microspheres can be formulated for effective sustained and
targeted delivery to host macrophages.
PMID- 9756778
TI - Haemophilus ducreyi is susceptible to protegrin.
AB - Protegrins, potent antimicrobial peptides found in porcine leukocytes, have
activity against the sexually transmitted pathogens Neisseria gonorrhoeae,
Chlamydia trachomatis, and human immunodeficiency virus type 1. We tested
synthetic protegrin 1 (PG-1) for activity against nine isolates of Haemophilus
ducreyi, the etiologic agent of chancroid. The test organisms included CIP 542
(the type strain), 35000HP (a human-passaged variant of 35000), 35000HP-RSM2 (an
isogenic D-glycero-D-manno-heptosyltransferase mutant of 35000HP), and six
clinical isolates. The isolates were epidemiologically unrelated, represented
three HindIII ribotypes, and had varying antimicrobial resistance patterns. In
bactericidal assays, five isolates were rapidly killed by synthetic PG-1. In
radial diffusion assays, all nine isolates were exquisitely sensitive to PG-1.
These data highlight the potential of protegrins for development as topical
agents to prevent many sexually transmitted diseases, including chancroid.
PMID- 9756779
TI - Translation elongation factor 2 is part of the target for a new family of
antifungals.
AB - Translation elongation factor 2 (EF2), which in Saccharomyces cerevisiae is
expressed from the EFT1 and EFT2 genes, has been found to be targeted by a new
family of highly specific antifungal compounds derived from the natural product
sordarin. Two complementation groups of mutants resistant to the semisynthetic
sordarin derivative GM193663 were found. The major one (21 members) consisted of
isolates with mutations on EFT2. The minor one (four isolates) is currently being
characterized but it is already known that resistance in this group is not due to
mutations on EFT1, pointing to the complex structure of the functional target for
these compounds. Mutations on EF2 clustered, forming a possible drug binding
pocket on a three-dimensional model of EF2, and mutant cell extracts lost the
capacity to bind to the inhibitors. This new family of antifungals holds the
promise to be a much needed and potent addition to current antimicrobial
treatments, as well as a useful tool for dissection of the elongation process in
ribosomal protein synthesis.
PMID- 9756780
TI - Compartmental pharmacokinetics and tissue drug distribution of the pradimicin
derivative BMS 181184 in rabbits.
AB - The pharmacokinetics of the antifungal pradimicin derivative BMS 181184 in plasma
of normal, catheterized rabbits were characterized after single and multiple
daily intravenous administrations of dosages of 10, 25, 50, or 150 mg/kg of body
weight, and drug levels in tissues were assessed after multiple dosing.
Concentrations of BMS 181184 were determined by a validated high-performance
liquid chromatography method, and plasma data were modeled into a two-compartment
open model. Across the investigated dosage range, BMS 181184 demonstrated
nonlinear, dose-dependent kinetics with enhanced clearance, reciprocal shortening
of elimination half-life, and an apparently expanding volume of distribution with
increasing dosage. After single-dose administration, the mean peak plasma BMS
181184 concentration (Cmax) ranged from 120 microg/ml at 10 mg/kg to 648
microg/ml at 150 mg/kg; the area under the concentration-time curve from 0 to 24
h (AUC0-24) ranged from 726 to 2,130 microg . h/ml, the volume of distribution
ranged from 0.397 to 0.799 liter/kg, and the terminal half-life ranged from 4.99
to 2.31 h, respectively (P < 0.005 to P < 0.001). No drug accumulation in plasma
occurred after multiple daily dosing at 10, 25, or 50 mg/kg over 15 days,
although mean elimination half-lives were slightly longer. Multiple daily dosing
at 150 mg/kg was associated with enhanced total clearance and a significant
decrease in AUC0-24 below the values obtained at 50 mg/kg (P < 0.01) and after
single-dose administration of the same dosage (P < 0.05). Assessment of tissue
BMS 181184 concentrations after multiple dosing over 16 days revealed substantial
uptake in the lungs, liver, and spleen and, most notably, dose-dependent
accumulation of the drug within the kidneys. These findings are indicative of
dose- and time-dependent elimination of BMS 181184 from plasma and renal
accumulation of the compound after multiple dosing.
PMID- 9756781
TI - Single-dose pharmacokinetics of a pleconaril (VP63843) oral solution and effect
of food.
AB - Pleconaril is an orally active broad-spectrum antipicornaviral agent which
demonstrates excellent penetration into the central nervous system, liver, and
nasal epithelium. We report the results of a randomized two-way crossover study
designed to characterize the disposition of a single dose (200 mg) of pleconaril
oral solution in fed and fasting humans. Twelve healthy adult subjects (18.7 to
39 years of age) participated in this study. Each subject received a single 200
mg dose of pleconaril oral solution, both coadministered with a standard English
breakfast and following a 10-h predose fast. There was a minimum 7-day washout
period between pleconaril doses. Repeated blood samples (n = 10) were obtained
over 24 h postdose, and the pleconaril level in plasma was quantified by gas
chromatography. Plasma concentration-versus-time data were curve fitted for each
subject by using a nonlinear weighted least-squares algorithm, and
pharmacokinetic parameters were determined from the polyexponential estimates.
Pleconaril disposition was best characterized by a one-compartment open model
with first-order absorption. The apparent bioavailability of pleconaril oral
solution was significantly increased with the administration of food. The area
under the concentration-time curve and maximum concentration of pleconaril in
plasma achieved following the standard English breakfast (i.e., 9.08 +/- 3.23
mg/liter . h and 1.14 +/- 0.58 mg/liter, respectively) were 2.2- and 2.5-fold
higher, respectively than those achieved in the fasting state (i.e., 4.08 +/-
2.74 mg/liter . h and 0.46 +/- 0.30 mg/liter, respectively). Mean plasma
pleconaril concentrations 12 h after a single 200-mg oral dose (fed, 0.25 +/- 0.2
mg/liter; fasting, 0.11 +/- 0.10 mg/liter) in healthy adults remained greater
than that required to inhibit more than 90% of the enteroviruses in cell culture
(i.e., 0.07 mg/liter). To enhance the oral bioavailability of pleconaril,
coadministration with a fat-containing meal is recommended.
PMID- 9756783
TI - Antitrypanosomal activity of a new triazine derivative, SIPI 1029, In vitro and
in model infections.
AB - A recently developed diaminotriazine derivative [O,O'-bis(1, 2-dihydro-2,2
tetramethylene-4,6-diamino-S-triazin-1-yl)-1, 6-hexanediol dihydrochloride; T-46;
SIPI 1029] was examined for activity against African trypanosomes in in vitro and
in vivo model systems. In vitro, SIPI 1029 was 50% inhibitory for growth of
bloodstream trypomastigotes of four strains of Trypanosoma brucei brucei and
Trypanosoma brucei rhodesiense at 0.15 to 2.15 nM (50% inhibitory
concentrations). In in vivo mouse laboratory models of T. b. rhodesiense clinical
isolate infections, SIPI 1029 was curative for 12 of 13 isolates at =10 mg/kg
of body weight/day for 3 days. In eight infections, a single dose was >/=60%
curative, and in six of these, a dose of =5 mg/kg was sufficient for >/=60%
cure rates. A number of these isolates were resistant to the standard trypanocide
melarsoprol (Arsobal) and/or the diamidines diminazene aceturate (Berenil) and
pentamidine. SIPI 1029 was also curative in combination with DL-alpha
difluoromethylornithine (Ornidyl) in a T. b. brucei central nervous system model
infection. Some evidence of toxicity was found in dosage regimens of 10 mg/kg/day
for 2 or 3 days in which deaths were observed in 6 of 65 animals given this
dosage regimen. The activity of SIPI 1029 in this study indicates that this class
of compounds (diaminotriazines) should be explored as leads for new human and
veterinary trypanocides.
PMID- 9756782
TI - Treatment of vancomycin-resistant Enterococcus faecium with RP 59500
(quinupristin-dalfopristin) administered by intermittent or continuous infusion,
alone or in combination with doxycycline, in an in vitro pharmacodynamic
infection model with simulated endocardial vegetations.
AB - Quinupristin-dalfopristin is a streptogramin antibiotic combination with activity
against vancomycin-resistant Enterococcus faecium (VREF), but emergence of
resistance has been recently reported. We studied the activity of quinupristin
dalfopristin against two clinical strains of VREF (12311 and 12366) in an in
vitro pharmacodynamic model with simulated endocardial vegetations (SEVs) to
determine the potential for resistance selection and possible strategies for
prevention. Baseline MICs/minimal bactericidal concentrations (microg/ml) for
quinupristin-dalfopristin, quinupristin, dalfopristin, and doxycycline were
0.25/2, 64/>512, 4/512, and 0.125/8 for VREF 12311 and 0.25/32, 128/>512, 2/128,
and 0.25/16 for VREF 12366, respectively. Quinupristin-dalfopristin regimens had
significantly less activity against VREF 12366 than VREF 12311. An 8-microg/ml
simulated continuous infusion was the only bactericidal regimen with time to
99.9% killing = 90 hours. The combination of quinupristin-dalfopristin every 8 h
with doxycycline resulted in more killing compared to either drug alone.
Quinupristin-dalfopristin-resistant mutants (MICs, 4 microg/ml; resistance
proportion, approximately 4 x 10(-4)) emerged during the quinupristin
dalfopristin monotherapies for both VREF strains. Resistance was unstable in VREF
12311 and stable in VREF 12366. The 8-microg/ml continuous infusion or addition
of doxycycline to quinupristin-dalfopristin prevented the emergence of resistance
for both strains over the 96-h test period. These findings replicated the
development of resistance reported in humans and emphasized bacterial factors
(drug susceptibility, high inoculum, organism growth phase) and infectious
conditions (penetration barriers) which could increase chances for clinical
resistance. The combination of quinupristin-dalfopristin with doxycycline and the
administration of quinupristin-dalfopristin as a high-dose continuous infusion
warrant further study to determine their potential clinical utility.
PMID- 9756784
TI - Visceral leishmaniasis in the BALB/c mouse: a comparison of the efficacy of a
nonionic surfactant formulation of sodium stibogluconate with those of three
proprietary formulations of amphotericin B.
AB - In this study, treatment efficacies of a nonionic surfactant vesicle formulation
of sodium stibogluconate (SSG-NIV) and of several formulations of amphotericin B
were compared in a murine model of visceral leishmaniasis. Treatment with
multiple doses of AmBisome, Abelcet, and Amphocil (total dose, 12.5 mg of
amphotericin B/kg of body weight) resulted in a significant suppression of
parasite burdens in liver (P < 0.0005) and spleen (P < 0.0005) compared with
those of controls, with Abelcet having the lowest activity. Only AmBisome and
Amphocil gave significant suppression of parasites in bone marrow (compared to
control values, P < 0.005). In the acute-infection model, single-dose treatments
of SSG-NIV (296 mg of SbV/kg), SSG solution (296 mg of SbV/kg), or AmBisome (8 mg
of amphotericin B/kg) were equally effective against liver parasites (compared to
control values, P < 0.0005). SSG-NIV and AmBisome treatment also significantly
suppressed parasites in bone marrow and spleen (P < 0.005), with SSG-NIV
treatment being more suppressive (>98% suppression in all three sites). Free-SSG
treatment failed to suppress spleen or bone marrow parasites. Infection status
influenced treatment outcome. In the chronic-infection model, the AmBisome single
dose treatment was less effective in all three infection sites and the SSG-NIV
single-dose treatment was less effective in the spleen. The results of this study
suggest that the antileishmanial efficacy of SSG-NIV compares favorably with
those of the novel amphotericin B formulations.
PMID- 9756785
TI - In vitro activity of the echinocandin antifungal agent LY303,366 in comparison
with itraconazole and amphotericin B against Aspergillus spp.
AB - LY303,366 (LY) is a novel derivative of the echinocandin class of antifungal
agents. The in vitro activities of LY, itraconazole (ITZ), and amphotericin B
(AMB) were assessed against 60 Aspergillus isolates, including 35 isolates of A.
fumigatus, eight isolates of A. terreus, eight isolates of A. flavus, eight
isolates of A. niger and one isolate of A. nidulans. Four A. fumigatus isolates
were resistant to ITZ. Susceptibility testing for all drugs was performed with a
broth microdilution procedure. LY was tested in two media: antibiotic medium 3
(AM3) and Casitone with 2% glucose (CAS) with an inoculum of 2 x 10(3) spores/ml.
ITZ and AMB were tested in RPMI 1640 with 2% glucose with an inoculum of 1 x
10(6) spores/ml. All tests were incubated at 37 degrees C for 48 h. A novel end
point was used to determine a minimal effective concentration (MEC) for LY, i.
e., almost complete inhibition of growth save a few tiny spherical colonies
attached to the microplate. MICs were measured for ITZ and AMB with a no-growth
end point. Ranges and geometric mean (GM) MECs were from 0.0018 to >0.5 and
0.0039 mg/liter and from 0.0018 to >0.5 and 0.008 mg/liter for LY in AM3 and LY
in CAS, respectively. Differences between species were apparent, with A. flavus
being significantly less susceptible to LY than any other species tested with
both media (P = 0.05). Ranges and GM MICs were from 0.125 to >16 and 0.7
mg/liter for ITZ and from 0.25 to 16 and 1.78 mg/liter for AMB. Minimal
fungicidal concentrations (MFCs) were also determined for all drugs. GM MFCs were
0.018, 0.09, 19.76, and 12.64 mg/liter for LY in AM3, LY in CAS, ITZ, and AMB,
respectively. LY in AM3 and LY in CAS were fungicidal for 86.7 and 68% of
isolates, respectively (98% killing). In comparison, ITZ and AMB were fungicidal
for 35 and 70% of isolates, respectively (99.99% killing). A reproducibility
study was performed on 20% of the isolates. For 12 isolates retested, the MEC or
MIC was the same or was within 1 dilution of the original value for 11, 11, 10,
and 9 isolates for LY in AM3, LY in CAS, ITZ, and AMB, respectively. In
conclusion, LY seems to be a promising antifungal agent with excellent in vitro
activity against Aspergillus spp.
PMID- 9756787
TI - In vitro studies of pharmacodynamic properties of vancomycin against
Staphylococcus aureus and Staphylococcus epidermidis.
AB - The bactericidal activities of vancomycin against two reference strains and two
clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis were
studied with five different concentrations ranging from 2x to 64x the MIC. The
decrease in the numbers of CFU at 24 h was at least 3 log10 CFU/ml for all
strains. No concentration-dependent killing was observed. The postantibiotic
effect (PAE) was determined by obtaining viable counts for two of the reference
strains, and the viable counts varied markedly: 1.2 h for S. aureus and 6.0 h for
S. epidermidis. The determinations of the PAE, the postantibiotic sub-MIC effect
(PA SME), and the sub-MIC effect (SME) for all strains were done with BioScreen
C, a computerized incubator for bacteria. The PA SMEs were longer than the SMEs
for all strains tested. A newly developed in vitro kinetic model was used to
expose the bacteria to continuously decreasing concentrations of vancomycin. A
filter prevented the loss of bacteria during the experiments. One reference
strain each of S. aureus and S. epidermidis and two clinical isolates of S.
aureus were exposed to an initial concentration of 10x the MIC of vancomycin with
two different half-lives (t1/2s): 1 or 5 h. The post-MIC effect (PME) was
calculated as the difference in time for the bacteria to grow 1 log10 CFU/ml from
the numbers of CFU obtained at the time when the MIC was reached and the
corresponding time for an unexposed control culture. The difference in PME
between the strains was not as pronounced as that for the PAE. Furthermore, the
PME was shorter when a t1/2 of 5 h (approximate terminal t1/2 in humans) was
used. The PMEs at t1/2s of 1 and 5 h were 6.5 and 3.6 h, respectively, for S.
aureus. The corresponding figures for S. epidermidis were 10.3 and less than 6 h.
The shorter PMEs achieved with a t1/2 of 5 h and the lack of concentration
dependent killing indicate that the time above the MIC is the parameter most
important for the efficacy of vancomycin.
PMID- 9756786
TI - Proteasome inhibitors block development of Plasmodium spp.
AB - Proteasomes degrade most of the proteins inside eukaryotic cells, including
transcription factors and regulators of cell cycle progression. Here we show that
nanomolar concentrations of lactacystin, a specific irreversible inhibitor of the
20S proteasome, inhibit development of the exoerythrocytic and erythrocytic
stages of the malaria parasite. Although lactacystin-treated Plasmodium berghei
sporozoites are still invasive, their development into exoerythrocytic forms
(EEF) is inhibited in vitro and in vivo. Erythrocytic schizogony of P. falciparum
in vitro is also profoundly inhibited when drug treatment of the synchronized
parasites is prior, but not subsequent, to the initiation of DNA synthesis,
suggesting that the inhibitory effect of lactacystin is cell cycle specific.
Lactacystin reduces P. berghei parasitemia in rats, but the therapeutic index is
very low. Along with other studies showing that lactacystin inhibits stage
specific transformation in Trypanosoma and Entamoeba spp., these findings
highlight the potential of proteasome inhibitors as drugs for the treatment of
diseases caused by protozoan parasites.
PMID- 9756788
TI - Enhancement of antimicrobial activity of neuropeptide Y by N-terminal truncation.
AB - The activity of neuropeptide Y (NPY) against Candida albicans, which was revealed
to be fungicidal, was enhanced significantly by the truncation of amino acid
residues at the N terminus. The most active peptides (MICs, approximately 1
microM) were about 10-fold more potent than the intact NPY (MIC, approximately 10
microM). The enhancement was weakened by the replacement of the N terminus by
negatively charged residues and/or acylation of the alpha-amino group. These
results suggest that only the alpha-helical region of NPY is necessary for the
antimicrobial activity and that the net charge of the peptide is important for
the activity.
PMID- 9756789
TI - In vitro susceptibility of Coxiella burnetii to trovafloxacin in comparison with
susceptibilities to pefloxacin, ciprofloxacin, ofloxacin, doxycycline, and
clarithromycin.
AB - The antibiotic susceptibilities of eight Greek isolates of Coxiella burnetii to
trovafloxacin were determined by the shell vial assay. MICs of trovafloxacin and
ofloxacin ranged from 1 to 2 microg/ml, those of pefloxacin ranged from 1 to 4
microg/ml, those of ciprofloxacin ranged from 4 to 8 microg/ml, those of
doxycycline ranged from 1 to 2 microg/ml, and those of clarithromycin ranged from
2 to 4 microg/ml. Trovafloxacin exhibited no activity against C. burnetii at 4
microg/ml.
PMID- 9756790
TI - Explaining the bias in the 23S rRNA gene mutations associated with clarithromycin
resistance in clinical isolates of Helicobacter pylori.
AB - A single point mutation in the 23S rRNA gene of Helicobacter pylori is known to
confer resistance to clarithromycin. Most prevalent among clarithromycin
resistant clinical H. pylori isolates are the mutations from A-2142 to G and A
2143 to G in the 23S rRNA gene. The bias in the 23S rRNA gene mutations
conferring clarithromycin resistance may result from the higher MIC, stability of
resistance, and growth rate found for the strains with the above-mentioned
mutations.
PMID- 9756791
TI - In vitro activities of 15 antimicrobial agents against clinical isolates of South
African enterococci.
AB - The activities of a panel of currently available antibiotics and the
investigational agents LY 333328, linezolid, CL 331,002, CL 329,998, moxifloxacin
(BAY 12-8039), trovafloxacin, and quinupristin-dalfopristin against 274 clinical
isolates of enterococci were determined. No vancomycin resistance or beta
lactamase production was observed. Except for 12 isolates (all non-Enterococcus
faecalis) showing reduced susceptibility to quinupristin-dalfopristin (MIC, >/=4
microg/ml), the new agents exhibited promising in vitro antienterococcal
activity.
PMID- 9756792
TI - A new approach for early assessment of the epileptogenic potential of quinolones.
AB - The epileptogenic potential of pefloxacin and norfloxacin, two quinolone
antibiotics, was investigated in vivo in three different animal species by
measuring drug concentrations in cerebrospinal fluid (CSF), which is part of the
biophase, at the onset of convulsions. Interestingly, the pefloxacin-to
norfloxacin concentration ratios in CSF were virtually constant across the
species (7.0, 6.6, and 6.0 in mice, rats, and rabbits, respectively), suggesting
that this approach could be used to predict the relative epileptogenic potential
of quinolones in humans.
PMID- 9756793
TI - Characterization of IS18, an element capable of activating the silent aac(6')-Ij
gene of Acinetobacter sp. 13 strain BM2716 by transposition.
AB - Insertion sequence IS18 was detected by analysis of the spontaneous
aminoglycoside resistant mutant Acinetobacter sp. 13 strain BM2716-1. Insertion
of the element upstream from the silent acetyltransferase gene aac(6')-Ij created
a hybrid promoter that putatively accounts for the expression of the
aminoglycoside resistance gene. The 1, 074-bp IS18 element contained partially
matched (20 out of 26 bases) terminal inverted repeats, one of which overlapped
the 3' end of a 935-bp open reading frame potentially encoding a protein related
to the transposases of the IS30 family. IS18 was found in 6 out of 29 strains of
Acinetobacter sp. 13 but not in 10 strains each of A. baumannii and A.
haemolyticus.
PMID- 9756794
TI - In vitro susceptibilities of Chlamydia pneumoniae strains recovered from
atherosclerotic coronary arteries.
AB - Chlamydia pneumoniae strains have been recovered from arteriosclerotic coronary
arteries, but their antibiotic susceptibility profiles have not yet been
examined. We report in vitro susceptibility data for five cardiovascular C.
pneumoniae isolates. These strains did not differ significantly from respiratory
strains in their patterns of susceptibility to azithromycin, erythromycin,
roxithromycin, ofloxacin, doxycycline, rifampin, and penicillin G. Roxithromycin
was the most active macrolide, and rifampin was the most effective drug overall.
PMID- 9756795
TI - PMX-622 (polymyxin B-dextran 70) does not alter in vitro activities of 11
antimicrobial agents.
AB - Because of its capacity to neutralize the lethality of gram-negative bacterial
endotoxic lipopolysaccharides, PMX-622 (polymyxin B bound to dextran 70) is being
developed for possible adjunctive therapy of gram-negative sepsis. In this study,
it was determined that the in vitro antimicrobial activity of PMX-622 was minimal
and that it does not interfere with the in vitro antimicrobial activity of 11
antibiotics commonly used to treat gram-negative infections.
PMID- 9756796
TI - Description of two new isolates of Streptococcus pneumoniae in spain that are
highly resistant to cefotaxime.
AB - Two strains of Streptococcus pneumoniae isolated from sputum and bronchoalveolar
samples with high-level resistance to cefotaxime (MIC = 8 to 16 microg/ml) are
described. One of them, belonging to serogroup 19, was also highly resistant to
penicillin (MIC = 16 microg/ml), while the other, of serogroup 14, was
intermediate in its resistance to penicillin (MIC = 0.25 microg/ml). To our
knowledge, these are the first two strains to be isolated in Spain with such high
levels of resistance to cefotaxime.
PMID- 9756797
TI - Clustering of anophthalmia and microphthalmia. No clustering has been found-but a
link seems to exist with population density.
PMID- 9756798
TI - Ageing costs. Evidence to royal commission emphasises need for explicit standards
and funding.
PMID- 9756799
TI - Paediatric transplantation comes of age. The main problem now is shortage of
donors.
PMID- 9756800
TI - The European Medicines Evaluation Agency: open to criticism. Transparency must be
coupled with greater rigour.
PMID- 9756801
TI - Is the FDA approving drugs too fast?. Probably not--but drug recalls have sparked
debate.
PMID- 9756802
TI - The NHS's new information strategy. Emphasises putting information to work for
patients and staff, not technology.
PMID- 9756803
TI - Geographical variation in anophthalmia and microphthalmia in England, 1988-94.
AB - OBJECTIVE: To investigate the geographical variation and clustering of congenital
anophthalmia and microphthalmia in England, in response to media reports of
clusters. DESIGN: Comparison of pattern of residence at birth of cases of
anophthalmia and microphthalmia in England in 1988-94, notified to a special
register, with pattern of residence of all births. Three groups studied included
all cases, all severe cases, and all severe cases of unknown aetiology. OUTCOME
MEASURES: Prevalence rates of anophthalmia and microphthalmia by region and
district, and by ward population density and socioeconomic deprivation index of
enumeration district grouped into fifths. Clustering expressed as the tendency
for the three nearest neighbours of a case to be more likely to be cases than
expected by chance, or for there to be more cases within circles of fixed radius
of a case than expected by chance. RESULTS: The overall prevalence of
anophthalmia and microphthalmia was 1.0 per 10 000 births. Regional and district
variation in prevalence did not reach statistical significance. Prevalence was
higher in rural than urban areas: the relative risk in the group of wards of
lowest population density compared with the most densely populated group was 1.79
(95% confidence interval 1.15 to 2.81) for all cases and 2.37 (1.38 to 4. 08) for
severe cases. There was no evidence of a trend in risk with socioeconomic
deprivation. There was very little evidence of localised clustering. CONCLUSIONS:
There is very little evidence to support the presence of strongly localised
environmental exposures causing clusters of children to be born with anophthalmia
or microphthalmia. The excess risk in rural areas requires further investigation.
PMID- 9756805
TI - Diagnostic trends
PMID- 9756804
TI - The hazards of self management
PMID- 9756806
TI - Serendipidity
PMID- 9756808
TI - Extracorporeal membrane oxygenation
PMID- 9756807
TI - Economic evaluation and randomised controlled trial of extracorporeal membrane
oxygenation: UK collaborative trial. The Extracorporeal Membrane Oxygenation
Economics Working Group.
AB - OBJECTIVE: To compare the resource implications and short term outcomes of
extracorporeal membrane oxygenation and conventional management for term babies
with severe respiratory failure. DESIGN: Cost effectiveness evaluation alongside
a randomised controlled trial. SETTING: 55 approved recruiting hospitals in the
United Kingdom. These hospitals provided conventional management, but infants
randomised to extracorporeal membrane oxygenation were transferred to one of five
specialist centres. SUBJECTS: 185 mature newborn infants (gestational age at
birth >35 weeks, birth weight >2 kg) with severe respiratory failure (oxygenation
index >40) recruited between 1993 and 1995. The commonest diagnoses were
persistent pulmonary hypertension due to meconium aspiration, congenital
diaphragmatic hernia, isolated persistent fetal circulation, sepsis, and
idiopathic respiratory distress syndrome. MAIN OUTCOME MEASURE: Cost
effectiveness based on survival at 1 year of age without severe disability.
RESULTS: 63 (68%) of the 93 infants randomised to extracorporeal membrane
oxygenation survived to 1 year compared with 38 (41%) of the 92 infants who
received conventional management. Of those that survived, one infant in each arm
was lost to follow up and the proportion with disability at 1 year was similar in
the two arms of the trial. One child in each arm had severe disability. The
estimated additional cost of extracorporeal membrane oxygenation per additional
surviving infant without severe disability was 51 222 pounds and the cost per
surviving infant with no disability was 75 327 pounds. CONCLUSIONS:
Extracorporeal membrane oxygenation for term neonates with severe respiratory
failure would increase overall survival without disability. Although the policy
will increase costs of neonatal health care, it is likely to be as cost effective
as other life extending technologies.
PMID- 9756809
TI - Income distribution, socioeconomic status, and self rated health in the United
States: multilevel analysis.
AB - OBJECTIVE: To determine the effect of inequalities in income within a state on
self rated health status while controlling for individual characteristics such as
socioeconomic status. DESIGN: Cross sectional multilevel study. Data were
collected on income distribution in each of the 50 states in the United States.
The Gini coefficient was used to measure statewide inequalities in income. Random
probability samples of individuals in each state were collected by the 1993 and
1994 behavioural risk factor surveillance system, a random digit telephone
survey. The survey collects information on an individual's income, education,
self rated health and other health risk factors. SETTING: All 50 states.
SUBJECTS: Civilian, non-institutionalised (that is, non-incarcerated and non
hospitalised) US residents aged 18 years or older. MAIN OUTCOME MEASURE: Self
rated health status. RESULTS: When personal characteristics and household income
were controlled for, individuals living in states with the greatest inequalities
in income were 30% more likely to report their health as fair or poor than
individuals living in states with the smallest inequalities in income.
CONCLUSIONS: Inequality in the distribution of income was associated with an
adverse impact on health independent of the effect of household income.
PMID- 9756810
TI - Trends in prenatal screening for and diagnosis of Down's syndrome: England and
Wales, 1989-97.
PMID- 9756811
TI - Effect of parity, gravidity, previous miscarriage, and age on risk of Down's
syndrome: population based study.
PMID- 9756812
TI - Bullying in schools: self reported anxiety, depression, and self esteem in
secondary school children.
PMID- 9756814
TI - An effective reproof
PMID- 9756813
TI - Postmarketing surveillance study of a non-chlorofluorocarbon inhaler according to
the safety assessment of marketed medicines guidelines.
AB - OBJECTIVE: To evaluate the safety of a non-chlorofluorocarbon metered dose
salbutamol inhaler. DESIGN: This was a postmarketing surveillance study,
conducted under formal guidelines for company sponsored safety assessment of
marketed medicines (SAMM). A non-randomised, non-interventional, observational
design compared patients prescribed metered doses of salbutamol delivered by
inhalers using either hydrofluoroalkane or chlorofluorocarbon as the propellant.
Follow up was three months. SETTING: 646 general practices throughout the United
Kingdom. SUBJECTS: 6614 patients with obstructive airways disease (1667 patient
years of exposure). MAIN OUTCOME MEASURES: Proportions of patients who were:
admitted to hospital for respiratory diseases, reported adverse side effects, or
withdrew because of adverse affects. RESULTS: There were no significant
differences between the hydrofluoroalkane (HFA 134a) and chlorofluorocarbon
inhaler groups in relation to the proportions of patients admitted to hospital
for respiratory diseases (odds ratio 0.75; 95% confidence interval 0.51 to 1.08)
or the proportions who reported adverse events (1.01; 0.88 to 1.17). However,
more patients using the hydrofluoroalkane inhaler than the chlorofluorocarbon
inhaler withdrew because of adverse events (3.8% and 0.9% respectively).
CONCLUSION: The hydrofluoroalkane inhaler was as safe as the chlorofluorocarbon
inhaler when judged by hospital admissions and adverse affects. The study design
successfully fulfilled the recommendations of the guidelines. Differences between
postmarketing surveillance studies and randomised clinical trials in assessing
safety were identified. These may lead to difficulties in the design of
postmarketing surveillance studies.
PMID- 9756816
TI - Car health
PMID- 9756815
TI - Xenotransplantation.
PMID- 9756818
TI - Harvard's swimming test
PMID- 9756817
TI - Provision of oxygen at home.
PMID- 9756819
TI - Certifying fitness for corporal punishment.
PMID- 9756820
TI - Long stay care and the NHS: discontinuities between policy and practice.
PMID- 9756821
TI - The new NHS: A medical reply to the minister
PMID- 9756822
TI - Sending the right message
PMID- 9756823
TI - New drug treatment for Alzheimer's disease. Doctors want to offer more than
sympathy.
PMID- 9756824
TI - Age is not only criterion for flu vaccine.
PMID- 9756825
TI - Discrepancy remains in pharmaceutical prescriptions in four European countries.
PMID- 9756827
TI - WHO haemoglobin colour scale is modern version of what was used previously.
PMID- 9756826
TI - Informed consent. Numbers inform the debate.
PMID- 9756828
TI - Protecting breast feeding from breast milk substitutes. Royal college supports
promotion of breast feeding.
PMID- 9756829
TI - Doctors and patients should sign prescriptions.
PMID- 9756830
TI - Planning the united Kingdom's medical workforce.
PMID- 9756831
TI - New Labour's new maths is hype.
PMID- 9756832
TI - Standardisation for age certainly changes proportions of doctors holding merit
awards.
PMID- 9756833
TI - David james mearns anderson
PMID- 9756834
TI - BMA and health minister will discuss review body remit
PMID- 9756835
TI - Going slowly
PMID- 9756836
TI - A bump on the head
PMID- 9756837
TI - School can be hell
PMID- 9756838
TI - The surgeon of crowthorne: A tale of murder, madness and the love of words
PMID- 9756839
TI - Chemical sensitivity: the truth about environmental illness
PMID- 9756841
TI - No clustering of anophthalmia occurs in england, but prevalence is higher in
rural areas
PMID- 9756840
TI - Caring for ageing populations
PMID- 9756843
TI - Health is poorer in US states with larger income inequalities
PMID- 9756842
TI - Extracorporeal membrane oxygenation can be cost effective
PMID- 9756845
TI - Bullied children are more anxious than their peers
PMID- 9756844
TI - Increased parity does not increase the risk of Down's syndrome
PMID- 9756846
TI - Inhalers are just as safe without chlorofluorocarbons
PMID- 9756847
TI - Solvation, reorganization energy, and biological catalysis.
PMID- 9756848
TI - The RNA-splicing factor PSF/p54 controls DNA-topoisomerase I activity by a direct
interaction.
AB - DNA-topoisomerase I has been implied in RNA splicing because it catalyzes RNA
strand transfer and activates serine/arginine-rich RNA-splicing factors by
phosphorylation. Here, we demonstrate a direct interaction between topoisomerase
I and pyrimidine tract binding protein-associated splicing factor (PSF), a
cofactor of RNA splicing, which forms heterodimers with its smaller homolog, the
nuclear RNA-binding protein of 54 kDa (p54). Topoisomerase I, PSF, and p54
copurified in a 1:1:1 ratio from human A431 cell nuclear extracts. Specific
binding of topoisomerase I to PSF (but not p54) was demonstrated by
coimmunoprecipitation and by far Western blotting, in which renatured blots were
probed with biotinylated topoisomerase I. Chemical cross-linking of pure
topoisomerase I revealed monomeric, dimeric, and trimeric enzyme forms, whereas
in the presence of PSF/p54 the enzyme was cross-linked into complexes larger than
homotrimers. When topoisomerase I was complexed with PSF/p54 it was 16-fold more
active than the pure enzyme, which could be stimulated 5- and 16-fold by the
addition of recombinant PSF or native PSF/p54, respectively. A physiological role
of this stimulatory mechanism seems feasible, because topoisomerase I and PSF
showed a patched colocalization in A431 cell nuclei, which varied with cell
cycle.
PMID- 9756849
TI - The putative tumor suppressors EXT1 and EXT2 are glycosyltransferases required
for the biosynthesis of heparan sulfate.
AB - Hereditary multiple exostoses, characterized by multiple cartilaginous tumors, is
ascribed to mutations at three distinct loci, denoted EXT1-3. Here, we report the
purification of a protein from bovine serum that harbored the D-glucuronyl (GlcA)
and N-acetyl-D-glucosaminyl (GlcNAc) transferase activities required for
biosynthesis of the glycosaminoglycan, heparan sulfate (HS). This protein was
identified as EXT2. Expression of EXT2 yielded a protein with both
glycosyltransferase activities. Moreover, EXT1, previously found to rescue
defective HS biosynthesis (McCormick, C., Leduc, Y., Martindale, D., Mattison,
K., Esford, L. E., Dyer, A. P., and Tufaro, F. (1998) Nat. Genet. 19, 158-161),
was shown to elevate the low GlcA and GlcNAc transferase levels of mutant cells.
Thus at least two members of the EXT family of tumor suppressors encode
glycosyltransferases involved in the chain elongation step of HS biosynthesis.
PMID- 9756850
TI - BEGAIN (brain-enriched guanylate kinase-associated protein), a novel neuronal PSD
95/SAP90-binding protein.
AB - PSD-95/SAP90 is a synaptic membrane-associated guanylate kinase with three PDZ,
one SH3, and one guanylate kinase (GK) domain. PSD-95/SAP90 binds various
proteins through the PDZ domains and organizes synaptic junctions. PSD-95/SAP90
also interacts with the postsynaptic density (PSD) fraction-enriched protein,
named SAPAP (also called GKAP and DAP), through the GK domain. SAPAP is Triton X
100-insoluble and recruits PSD-95/SAP90 into the Triton X-100-insoluble fraction
in the transfected cells, suggesting that SAPAP may fix PSD-95/SAP90 to the PSD.
Here we report a novel protein interacting with the GK domain of PSD-95/SAP90,
BEGAIN. BEGAIN is specifically expressed in brain and enriched in the PSD
fraction. BEGAIN is Triton X-100-soluble in the transfected cells but is
recruited to the Triton X-100-insoluble fraction by SAPAP when coexpressed with
PSD-95/SAP90. BEGAIN may be a novel PSD component associated with the core
complex of PSD-95/SAP90 and SAPAP.
PMID- 9756851
TI - The 100-kDa neurotensin receptor is gp95/sortilin, a non-G-protein-coupled
receptor.
AB - In this work, the 100-kDa neurotensin (NT) receptor previously purified from
human brain by affinity chromatography (Zsurger, N., Mazella, J., and Vincent, J.
P. (1994) Brain Res. 639, 245-252) was cloned from a human brain cDNA library.
This cDNA encodes a 833-amino acid protein 100% identical to the recently cloned
gp95/sortilin and was then designated NT3 receptor-gp95/sortilin. The N terminus
of the purified protein is identical to the sequence of the purified
gp95/sortilin located immediately after the furin cleavage site. The binding of
iodinated NT to 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid
solubilized extracts of COS-7 cells transfected with the cloned cDNA was
saturable and reversible with an affinity of 10-15 nM. The localization of the
NT3 receptor-gp95/sortilin into intracellular vesicles was in agreement with
previous results obtained with the purified receptor and with gp95/sortilin.
Affinity labeling and binding experiments showed that the 110-kDa NT3 receptor
can be partly transformed into a higher affinity (Kd = 0.3 nM) 100-kDa protein
receptor by cotransfection with furin. This 100-kDa NT receptor corresponded to
the mature form of the receptor. The NT3/gp95/sortilin protein is the first
transmembrane neuropeptide receptor that does not belong to the superfamily of G
protein-coupled receptors.
PMID- 9756852
TI - Activation of Sp1-mediated vascular permeability factor/vascular endothelial
growth factor transcription requires specific interaction with protein kinase C
zeta.
AB - The transcription factor Sp1 is ubiquitously expressed and plays a significant
role in the constitutive and induced expression of a variety of mammalian genes
and may even contribute to tumorigenesis. Here, we describe a novel pathway
whereby Sp1 promotes the transcription of vascular permeability factor/vascular
endothelial growth factor (VPF/VEGF), a potent angiogenic factor, by interacting
directly and specifically with protein kinase C zeta (PKC zeta) isoform in renal
cell carcinoma. PKC zeta binds and phosphorylates the zinc finger region of Sp1.
Moreover, in the presence of the wild type von Hippel-Lindau gene product, the
interaction of Sp1 with PKC zeta is inhibited, and in this manner steady state
levels of Sp1 phosphorylation are decreased significantly. Co-transfection of
renal cell carcinoma cells and human fibrosarcoma cells with a plasmid
overexpressing PKC zeta and VPF/VEGF promoter luciferase constructs results in
activation of Sp1-mediated transcription, whereas expression of a dominant
negative mutant of PKC zeta repressed this activation. Taken together, our
results suggest a new pathway of cell signaling through PKC zeta and provide an
insight into PKC zeta and Sp1-dependent transcriptional regulation of VPF/VEGF
expression and thus tumor angiogenesis.
PMID- 9756853
TI - T cell receptor zeta allows stable expression of receptors containing the
CD3gamma leucine-based receptor-sorting motif.
AB - The leucine-based motif in the T cell receptor (TCR) subunit CD3gamma constitutes
a strong internalization signal. In fully assembled TCR this motif is inactive
unless phosphorylated. In contrast, the motif is constitutively active in
CD4/CD3gamma and Tac/CD3gamma chimeras independently of phosphorylation and leads
to rapid internalization and sorting of these chimeras to lysosomal degradation.
Because the TCRzeta chain rescues incomplete TCR complexes from lysosomal
degradation and allows stable surface expression of fully assembled TCR, we
addressed the question whether TCRzeta has the potential to mask the CD3gamma
leucine-based motif. By studying CD4/CD3gamma and CD16/CD3gamma chimeras, we
found that CD16/CD3gamma chimeras associated with TCRzeta. The CD16/CD3gamma
TCRzeta complexes were stably expressed at the cell surface and had a low
spontaneous internalization rate, indicating that the leucine-based motif in
these complexes was inactive. In contrast, the CD4/CD3gamma chimeras did not
associate with TCRzeta, and the leucine-based motif in these chimeras was
constitutively active resulting in a high spontaneous internalization rate and
low expression of the chimeras at the cell surface. Thus, our data demonstrate
that TCRzeta allows stable cell surface expression of receptors containing
CD3gamma leucine-based motifs by its potential to mask such motifs.
PMID- 9756854
TI - Steroidogenic acute regulatory protein (StAR) is a sterol transfer protein.
AB - Steroidogenic acute regulatory protein (StAR) plays a critical role in
steroidogenesis by enhancing the delivery of substrate cholesterol from the outer
mitochondrial membrane to the cholesterol side chain cleavage enzyme system on
the inner membrane. A recombinant StAR protein lacking the first N-terminal 62
amino acid residues that includes the mitochondrial targeting sequence was shown
to stimulate the transfer of cholesterol and beta-sitosterol from liposomes to
heat-treated mitochondria in a dose-, time-, and temperature-dependent manner. A
recombinant mutant StAR protein that cannot stimulate steroidogenesis by isolated
mitochondria did not promote sterol transfer. Unlike the more promiscuous lipid
transfer protein, sterol carrier protein 2 (SCP2), StAR did not stimulate
phosphatidylcholine transfer in our assay system. The recombinant StAR protein
increased cholesterol transfer to heat-treated microsomes as well as to heat- and
trypsin-treated mitochondria. These observations demonstrate that StAR has sterol
transfer activity, which may reflect an ability to enhance desorption of
cholesterol from sterol-rich donor membranes. We suggest that the ability of StAR
to promote sterol transfer explains its steroidogenic activity.
PMID- 9756855
TI - The non-histone chromatin protein HMG1 protects linker DNA on the side opposite
to that protected by linker histones.
AB - Linker histones and HMG1/2 constitute the two major proteins that bind to linker
DNA in chromatin. While the location of linker histones on the nucleosome has
attracted considerable research effort, only a few studies have addressed the
location of HMG1 in the particles. In this study, we use a procedure based on
micrococcal nuclease digestion of reconstituted nucleosomal particles to which
HMG1 has been bound, followed by analysis of the protected DNA by restriction
nuclease digestion, to locate the HMG1 binding site. Nucleosomal particles were
reconstituted on a 235-base pair DNA fragment, which is known to be a strong
nucleosome positioning sequence. The results unequivocally show that HMG1
protects linker DNA on one side of the core particle. Importantly, and possibly
of physiological relevance, the linker DNA site protected by HMG1 was located on
the side opposite to that already shown to be protected by linker histone
binding.
PMID- 9756856
TI - Binding of alpha-synuclein to brain vesicles is abolished by familial Parkinson's
disease mutation.
AB - The presynaptic protein alpha-synuclein has been implicated in the pathogenesis
of Parkinson's disease. First, two missense mutations A30P and A53T cause
inheritable early onset Parkinson's disease in some families. Secondly, alpha
synuclein is present in Lewy bodies of affected nerve cells in the predominant
sporadic type of Parkinson's disease as well as in dementia with Lewy bodies. We
demonstrate in the rat optic system that a portion of alpha-synuclein is carried
by the vesicle-moving fast component of axonal transport and that it binds to rat
brain vesicles through its amino-terminal repeat region. We find alpha-synuclein
with the A30P mutation of familial Parkinson's disease devoid of vesicle-binding
activity and propose that mutant alpha-synuclein may accumulate, leading to
assembly into Lewy body filaments.
PMID- 9756857
TI - Glycosylasparaginase-catalyzed synthesis and hydrolysis of beta-aspartyl
peptides.
AB - beta-Aspartyl di- and tripeptides are common constituents of mammalian
metabolism, but their formation and catabolism are not fully understood. In this
study we provide evidence that glycosylasparaginase (aspartylglucosaminidase), an
N-terminal nucleophile hydrolase involved in the hydrolysis of the N-glycosidic
bond in glycoproteins, catalyzes the hydrolysis of beta-aspartyl peptides to form
L-aspartic acid and amino acids or peptides. The enzyme also effectively
catalyzes the synthesis of beta-aspartyl peptides by transferring the beta
aspartyl moiety from other beta-aspartyl peptides or beta-aspartylglycosylamine
to a variety of amino acids and peptides. Furthermore, the enzyme can use L
asparagine as the beta-aspartyl donor in the formation of beta-aspartyl peptides.
The data show that synthesis and degradation of beta-aspartyl peptides are new,
significant functions of glycosylasparaginase and suggest that the enzyme could
have an important role in the metabolism of beta-aspartyl peptides.
PMID- 9756858
TI - Production of human compatible high mannose-type (Man5GlcNAc2) sugar chains in
Saccharomyces cerevisiae.
AB - A yeast mutant capable of producing Man5GlcNAc2 human compatible sugar chains on
glycoproteins was constructed. An expression vector for alpha-1,2-mannosidase
with the "HDEL" endoplasmic reticulum retention/retrieval tag was designed and
expressed in Saccharomyces cerevisiae. An in vitro alpha-1,2-mannosidase assay
and Western blot analysis showed that it was successfully localized in the
endoplasmic reticulum. A triple mutant yeast lacking three glycosyltransferase
activities was then transformed with an alpha-1, 2-mannosidase expression vector.
The oligosaccharide structures of carboxypeptidase Y as well as cell surface
glycoproteins were analyzed, and the recombinant yeast was shown to produce a
series of high mannose-type sugar chains including Man5GlcNAc2. This is the first
report of a recombinant S. cerevisiae able to produce Man5GlcNAc2
oligosaccharides, the intermediate for hybrid-type and complex-type sugar chains.
PMID- 9756859
TI - Hydrolysis of ATP at only one GyrB subunit is sufficient to promote supercoiling
by DNA gyrase.
AB - Mutation of Glu42 to Ala in the B subunit of DNA gyrase abolishes ATP hydrolysis
but not nucleotide binding. Gyrase complexes that contain one wild-type and one
Ala42 mutant B protein were formed, and the ability of such complexes to
hydrolyze ATP was investigated. We found that ATP hydrolysis was able to proceed
independently only in the wild-type subunit, albeit at a lower rate. With only
one ATP molecule hydrolyzed at a time, gyrase could still perform supercoiling,
but the limit of this reaction was lower than that observed when both subunits
can hydrolyze the nucleotide.
PMID- 9756860
TI - Involvement of waaY, waaQ, and waaP in the modification of Escherichia coli
lipopolysaccharide and their role in the formation of a stable outer membrane.
AB - The waaY, waaQ, and waaP genes are located in the central operon of the waa
(formerly rfa) locus on the chromosome of Escherichia coli. This locus contains
genes whose products are involved in the assembly of the core region of the
lipopolysaccharide molecule. In the R1 core prototype strain, E. coli F470, there
are nine genes in this operon, and all but waaY, waaQ, and waaP have been
assigned function. In this study, the waaY, waaQ, and waaP genes were
independently mutated by insertion of a non-polar antibiotic resistance cassette,
and the structures of the resulting mutant core oligosaccharides were determined
by chemical analyses and phosphorus-nuclear magnetic resonance spectroscopy. All
three of these mutations were shown to affect the modification of the heptose
region of the core, a region whose structure is critical to outer membrane
stability. Mutation of waaY resulted in a core oligosaccharide devoid of
phosphate on HepII. Mutation of waaQ resulted in loss of the branch HepIII
residue on HepII and impeded the activity of WaaY. Mutation of waaP resulted in
loss of phosphoryl substituents on HepI and obviated WaaQ and WaaY activity. Only
mutation of waaP resulted in hypersensitivity to novobiocin and sodium dodecyl
sulfate, a characteristic of deep-rough mutations.
PMID- 9756861
TI - Trypanosoma brucei gamma-glutamylcysteine synthetase. Characterization of the
kinetic mechanism and the role of Cys-319 in cystamine inactivation.
AB - The parasitic protozoan Trypanosoma brucei utilizes a conjugate of glutathione
and spermidine, termed trypanothione, in place of glutathione to maintain
cellular redox balance. The first committed step in the biosynthesis of
glutathione and thereby trypanothione, is catalyzed by gamma-glutamylcysteine
synthetase (gamma-GCS). We have determined the kinetic mechanism for T. brucei
gamma-GCS. The kinetics are best described by a rapid equilibrium random ter
reactant mechanism, in which the model derived Kd values for the binding of L
Glu, L-alpha-aminobutyrate, and ATP to free enzyme are 2.6, 5.1, and 1.4 mM,
respectively. However, significant dependences exist between the binding of some
of the substrate pairs. The binding of either ATP or L-Glu to the enzyme
increases the binding affinity of the other by 18-fold, whereas the binding of L
Glu or L-alpha-aminobutyrate decreases the binding affinity of the other by 6
fold. Similarly to the mammalian enzyme, cystamine is a time-dependent,
irreversible inhibitor of T. brucei gamma-GCS. It has been suggested by several
studies that cystamine labels an active site Cys residue essential for catalysis.
Among the enzymes reported to be inactivated by cystamine, only one Cys residue
is invariant (Cys-319 in T. brucei gamma-GCS). Mutation of Cys-319 to Ala in T.
brucei gamma-GCS renders the enzyme insensitive to cystamine inactivation without
significantly affecting the enzyme's catalytic efficiency, kinetic mechanism, or
substrate affinities. These studies suggest that cystamine inactivates the enzyme
by blocking substrate access to the active site and not by labeling an essential
active site residue.
PMID- 9756862
TI - Rapid mechanotransduction in situ at the luminal cell surface of vascular
endothelium and its caveolae.
AB - The vascular endothelium is uniquely positioned between the blood and tissue
compartments to receive directly the fluid forces generated by the blood flowing
through the vasculature. These forces invoke specific responses within
endothelial cells and serve to modulate their intrinsic structure and function.
The mechanisms by which hemodynamic forces are detected and converted by
endothelia into a sequence of biological and even pathological responses are
presently unknown. By purifying and subfractionating the luminal endothelial cell
plasma membrane from tissue, we show, for the first time, that not only does
mechanotransduction occur at the endothelial cell surface directly exposed to
vascular flow in vivo but also increased flow in situ induces rapid tyrosine
phosphorylation of luminal endothelial cell surface proteins located primarily in
the plasmalemmal invaginations called caveolae. Increased flow induces the
translocation of signaling molecules primarily to caveolae, ultimately activating
the Ras-Raf-mitogen-activated protein kinase pathway. This signaling appears to
require intact caveolae. Filipin-induced disassembly of caveolae inhibits both
proximal signaling events at the cell surface and downstream activation of the
mitogen-activated protein kinase pathway. With the molecular machinery required
for mediating rapid flow-induced responses as seen in endothelium, caveolae may
be flow-sensing organelles converting mechanical stimuli into chemical signals
transmitted into the cell.
PMID- 9756863
TI - An all-ferrous state of the Fe protein of nitrogenase. Interaction with
nucleotides and electron transfer to the MoFe protein.
AB - The MoFe protein of nitrogenase catalyzes the six-electron reduction of
dinitrogen to ammonia. It has long been believed that this protein receives the
multiple electrons it requires one at a time, from the [4Fe-4S]2+/+ couple of the
Fe protein. Recently an all-ferrous [4Fe-4S]0 state of the Fe protein was
demonstrated suggesting instead a series of two electron steps involving the [4Fe
4S]2+/0 couple. We have examined the interactions of the [4Fe-4S]0 Fe protein
with nucleotides and its ability to transfer electrons to the MoFe protein. The
[4Fe-4S]0 Fe protein binds both MgATP and MgADP and undergoes the MgATP induced
conformational change and then binds properly to the MoFe protein, as evidenced
by the fact that the behavior of the 0 and +1 oxidation states in the chelation
and chelation protection assays are indistinguishable. Nucleotide binding does
not effect the distinctive UV/Vis, CD, or Mossbauer spectra exhibited by the [4Fe
4S]0 Fe protein; however, because the intensity of the g = 16.4 EPR signal of the
[4Fe-4S]0 Fe protein is extremely sensitive to minor variations of the rhombicity
parameter E/D, the EPR signal is sensitive to the binding of nucleotides. A 50:50
mixture of [4Fe-4S]2+ and [4Fe-4S]0 Fe protein results in electron self-exchange
and 100% production of [4Fe-4S]+ Fe protein, demonstrating that the +1/0 couple
is fully reversible. MgATP is absolutely required for electron transfer from the
[4Fe-4S]0 Fe protein to the reduced state of the MoFe protein. In that reaction
both electrons are transferred and are used to reduce substrate.
PMID- 9756864
TI - The efficient cellular uptake of high density lipoprotein lipids via scavenger
receptor class B type I requires not only receptor-mediated surface binding but
also receptor-specific lipid transfer mediated by its extracellular domain.
AB - The class B type I scavenger receptor, (SR-BI), is a member of the CD36
superfamily of proteins and is a physiologically relevant, high affinity cell
surface high density lipoprotein (HDL) receptor that mediates selective lipid
uptake. The mechanism of selective lipid uptake is fundamentally different from
that of classic receptor-mediated uptake via coated pits and vesicles (e.g. the
low density lipoprotein receptor pathway) in that it involves efficient transfer
of the lipids, but not the outer shell proteins, from HDL to cells. The abilities
of SR-BI and CD36, both of which are class B scavenger receptors, to bind HDL and
mediate cellular uptake of HDL-associated lipid when transiently expressed in COS
cells were examined. For these experiments, the binding of HDL to cells was
assessed using either 125I- or Alexa (a fluorescent dye)-HDL in which the
apolipoproteins on the surface of the HDL particles were covalently modified.
Lipid transfer was measured using HDL noncovalently labeled by the fluorescent
lipid 1,1'-dioctadecyl-3,3, 3',3'-tetramethylindocarbocyanine perchlorate.
Although both mSR-BI and human CD36 (hCD36) could mediate the binding of HDL in a
punctate pattern across the surfaces of cells, only mSR-BI efficiently mediated
the transfer of lipid to the cells. Analysis of point mutants established that
the major sites of fatty acylation of mSR-BI are Cys462 and Cys470 and that fatty
acylation is not required for receptor clustering, HDL binding, or efficient
lipid transfer. Generation of mSR-BI/hCD36 domain swap chimeras showed that the
differences in lipid uptake activities between mSR-BI and hCD36 were not due to
differences between their two sets of transmembrane and cytoplasmic domains but
rather result from differences in their large extracellular loop domains. These
results show that high affinity binding to a cell surface receptor is not
sufficient to ensure efficient cellular lipid uptake from HDL. Thus, SR-BI
mediated binding combined with SR-BI-dependent facilitated transfer of lipid from
the HDL particle to the cell appears to be the most likely mechanism for the bulk
of the selective uptake of cholesteryl esters from HDL to the liver and
steroidogenic tissues.
PMID- 9756865
TI - Structural analysis of the fds operon encoding the NAD+-linked formate
dehydrogenase of Ralstonia eutropha.
AB - The fdsGBACD operon encoding the four subunits of the NAD+-reducing formate
dehydrogenase of Ralstonia eutropha H16 was cloned and sequenced. Sequence
comparisons indicated a high resemblance of FdsA (alpha-subunit) to the catalytic
subunits of formate dehydrogenases containing a molybdenum (or tungsten)
cofactor. The NH2-terminal region (residues 1-240) of FdsA, lacking in formate
dehydrogenases not linked to NAD(P)+, exhibited considerable similarity to that
of NuoG of the NADH:ubiquinone oxidoreductase from Escherichia coli as well as to
HoxU and the NH2-terminal segment of HndD of NAD(P)+-reducing hydrogenases. FdsB
(beta-subunit) and FdsG (gamma-subunit) are closely related to NuoF and NuoE,
respectively, as well as to HoxF and HndA. It is proposed that the NH2-terminal
domain of FdsA together with FdsB and FdsG constitute a functional entity
corresponding to the NADH dehydrogenase (diaphorase) part of NADH:ubiquinone
oxidoreductase and the hydrogenases. No significant similarity to any known
protein was observed for FdsD (delta-subunit). The predicted product of fdsC
showed the highest resemblance to FdhD from E. coli, a protein required for the
formation of active formate dehydrogenases in this organism. Transcription of the
fds operon is subject to formate induction. A promoter structure resembling the
consensus sequence of sigma70-dependent promoters from E. coli was identified
upstream of the transcriptional start site determined by primer extension
analysis.
PMID- 9756866
TI - Intracellular retention of recombinant GABAB receptors.
AB - gamma-Aminobutyric acid type B (GABAB) receptors mediate the transmission of slow
and prolonged inhibitory signals in the central nervous system. Two splice
variants of GABAB receptors, GABABR1a and GABABR1b, were recently cloned from a
mouse cortical and cerebellar cDNA library. As predicted, these receptors belong
to the G protein-coupled receptor superfamily. We have used epitope-tagged
versions of GABABR1a receptors to study the cellular distribution of these
proteins in a variety of non-neuronal and neuronal cell types. Here we report
that recombinant GABAB receptors fail to reach the cell surface when expressed in
heterologous systems and are retained in the endoplasmic reticulum when
introduced into COS cells. In addition, we prove that recombinant GABAB receptors
are excluded from the cell surface when overexpressed in ganglion neurons and we
further demonstrate that they fail to activate in superior cervical ganglion
neurons. Together our observations suggest that recombinant GABAB receptors
require additional information for functional targeting to the plasma membrane.
PMID- 9756867
TI - Molecular basis for substrate specificity of protein-tyrosine phosphatase 1B.
AB - Protein-tyrosine phosphatases can exhibit stringent substrate specificity in
vivo, although the molecular basis for this is not well understood. The three
dimensional structure of the catalytically inactive protein-tyrosine phosphate 1B
(PTP1B)/C215S complexed with an optimal substrate, DADEpYL-NH2, reveals specific
interactions between amino acid residues in the substrate and PTP1B. The goal of
this work is to rigorously evaluate the functional significance of Tyr46, Arg47,
Asp48, Phe182, and Gln262 in substrate binding and catalysis, using site-directed
mutagenesis. Combined with structural information, kinetic analysis of the wild
type and mutant PTP1B using p-nitrophenyl phosphate and phosphotyrosine
containing peptides has yielded further insight into PTP1B residues, which
recognize general features, as well as specific properties, in peptide
substrates. In addition, the kinetic results suggest roles of these residues in E
P hydrolysis, which are not obvious from the structure of PTP1B/peptide complex.
Thus, Tyr46 and Asp48 recognize common features of peptide substrates and are
important for peptide substrate binding and/or E-P formation. Arg47 acts as a
determinant of substrate specificity and is responsible for the modest preference
of PTP1B for acidic residues NH2-terminal to phosphotyrosine. Phe182 and the
invariant Gln262 are not only important for substrate binding and/or E-P
formation but also important for the E-P hydrolysis step.
PMID- 9756868
TI - Importance of phenylalanine residues of yeast calmodulin for target binding and
activation.
AB - Recent genetic studies of yeast calmodulin (yCaM) have shown that alterations of
different sets of Phe residues result in distinct functional defects (Ohya, Y.,
and Botstein, D. (1994) Science 263, 963-966). To examine the importance of Phe
residues for target binding and activation, we purified mutant yCaMs containing
single or double Phe to Ala substitutions and determined their ability to bind
and activate two target proteins, calcineurin and CaM-dependent protein kinase
(CaMK). Binding assays using the gel overlay technique and quantitative analyses
using surface plasmon resonance measurements indicated that the binding of yCaM
to calcineurin is impaired by either double mutations of F16A/F19A or a single
mutation of F140A, while binding to CaMK is impaired by F89A, F92A, or F140A.
These same mutant yCaMs fail to activate calcineurin and CaMK, respectively, in
vitro. In addition, F19A exhibited a severe defect in activation of both enzymes.
F12A activated calcineurin to only 50% of the level achieved by wild-type
calmodulin but fully activated CaMK. These results suggest that each target
protein requires a specific and distinct subset of Phe residues in yCaM for
target binding and activation.
PMID- 9756869
TI - Mechanism of cloned ATP-sensitive potassium channel activation by oleoyl-CoA.
AB - Insulin secretion from pancreatic beta cells is coupled to cell metabolism
through closure of ATP-sensitive potassium (KATP) channels, which comprise Kir6.2
and sulfonylurea receptor (SUR1) subunits. Although metabolic regulation of KATP
channel activity is believed to be mediated principally by the adenine
nucleotides, other metabolic intermediates, including long chain acyl-CoA esters,
may also be involved. We recorded macroscopic and single-channel currents from
Xenopus oocytes expressing either Kir6.2/SUR1 or Kir6. 2DeltaC36 (which forms
channels in the absence of SUR1). Oleoyl-CoA (1 microM) activated both wild-type
Kir6.2/SUR1 and Kir6.2DeltaC36 macroscopic currents, approximately 2-fold, by
increasing the number and open probability of Kir6.2/SUR1 and Kir6.2DeltaC36
channels. It was ineffective on the related Kir subunit Kir1.1a. Oleoyl-CoA also
impaired channel inhibition by ATP, increasing the Ki values for both Kir6.2/SUR1
and Kir6.2DeltaC36 currents by approximately 3-fold. Our results indicate that
activation of KATP channels by oleoyl-CoA results from an interaction with the
Kir6.2 subunit, unlike the stimulatory effects of MgADP and diazoxide which are
mediated through SUR1. The increased activity and reduced ATP sensitivity of KATP
channels by oleoyl-CoA might contribute to the impaired insulin secretion
observed in non-insulin-dependent diabetes mellitus.
PMID- 9756870
TI - Overexpression and accumulation of apolipoprotein E as a cause of
hypertriglyceridemia.
AB - The molecular mechanisms of hypertriglyceridemia (HTG), a common lipid metabolic
disorder in humans, often of genetic origin, are not well understood. In studying
the effect of apolipoprotein (apo) E on the metabolism of triglyceride-rich
lipoproteins, we found that expressing high plasma levels of human apoE3 in
transgenic mice lacking endogenous mouse apoE caused HTG. These transgenic
animals had 3-fold higher plasma triglyceride levels, higher very low density
lipoproteins (VLDL), and lower high density lipoproteins than did nontransgenics.
Removing one or both low density lipoprotein receptor alleles in the apoE3
overexpressing mice caused severe HTG (8-11-fold over nontransgenics) and
increased VLDL and decreased low and high density lipoproteins, and apoE3
enriched VLDL were markedly depleted in apoC-II. At least two mechanisms could
explain HTG associated with apoE3 overexpression: stimulated VLDL triglyceride
production and impaired VLDL lipolysis. The apoE3 mice with HTG had a 50%
increase in hepatic VLDL triglyceride production. Furthermore, overexpression of
apoE (E2, E3, or E4) in cultured hepatocytes (McA-RH7777 cells) correlated
positively with secretion of VLDL into the medium. However, apoE3 overexpression
associated HTG was only partially explained by VLDL overproduction, as
lipoprotein lipase-mediated VLDL lipolysis was also decreased 20-86% depending on
apoE3 levels, most likely by displacing or masking apoC-II on the particles. In
human subjects, HTG correlated positively with increased VLDL triglyceride and
plasma and VLDL apoE levels. However, plasma and VLDL apoE correlated negatively
with VLDL apoC-II levels and lipoprotein lipase-mediated VLDL lipolysis. Thus,
optimal expression of apoE is crucial for normal metabolism of triglyceride-rich
lipoproteins, and overexpression and/or accumulation of apoE may contribute to
HTG by stimulating VLDL triglyceride production and by impairing VLDL lipolysis.
The apoE3-overexpressing mice will be useful for studying the pathophysiology of
this disorder.
PMID- 9756871
TI - Potential of Escherichia coli GTP cyclohydrolase II for hydrolyzing 8-oxo-dGTP, a
mutagenic substrate for DNA synthesis.
AB - MutT protein of Escherichia coli prevents the occurrence of A:T --> C:G
transversion by hydrolyzing an oxidized form of dGTP, 8-oxo-7, 8-dihydro-2'
deoxyguanosine 5'-triphosphate (8-oxo-dGTP), which is produced by active oxygen
species. In a search for mutT-related genes, we found that the ribA gene,
encoding GTP cyclohydrolase II, is able to reduce the increased level of mutation
frequency of the mutT strain to almost the normal level, provided that the gene
product is overproduced. Purified preparations of Escherichia coli GTP
cyclohydrolase II protein as well as the histidine hexamer-tagged recombinant GTP
cyclohydrolase II protein efficiently hydrolyze 8-oxo-dGTP and 8-oxo-GTP,
producing 8-oxo-dGMP and 8-oxo-GMP, respectively. dGTP was not hydrolyzed by
these preparations. GTP cyclohydrolase II catalyzes conversion of GTP to 2, 5
diamino-6-hydroxy-4-(5-phosphoribosylamino)-pyrimidine, which constitutes the
first step for riboflavin synthesis. The Km values for the three types of guanine
nucleotides, GTP, 8-oxo-GTP, and 8-oxo-dGTP, were almost the same. In the mutT-
background, ribA- cells showed higher spontaneous mutation frequencies as
compared with that of ribA+ cells. Thus, GTP cyclohydrolase II, the ribA gene
product, has a potential to protect genetic material from the untoward effects of
endogenous oxygen radicals.
PMID- 9756872
TI - Topology of the Na+/proline transporter of Escherichia coli.
AB - Hydropathy profile analysis of the amino acid sequence of the Na+/proline
transporter of Escherichia coli (PutP) suggests that the protein consists of 12
transmembrane domains (TMs) which are connected by hydrophilic loops (Nakao, T.,
Yamato, I., and Anraku, Y. (1987) Mol. Gen. Genet. 208, 70-75). We have tested
this prediction by applying a gene fusion approach in combination with a Cys
accessibility analysis and site-specific proteolysis. Characterization of a
series of PutP-alkaline phosphatase (PhoA) and PutP-beta-galactosidase (LacZ)
hybrid proteins yields a reciprocal activity pattern of the reporter proteins
that is in agreement with the topology of TMs III to XII of the 12-helix model.
Placement of the PutP-PhoA and PutP-LacZ junction sites closer to the N terminus
does not yield conclusive results. As a prerequisite for further topology
studies, a functional PutP molecule devoid of all five native Cys residues (Cys
free PutP) is generated. Subsequently, amino acids in Cys-free PutP are replaced
individually with Cys, and the accessibility of the sulfhydryl groups is
analyzed. Surprisingly, Cys residues placed close to the N terminus of PutP (Ile
3 --> Cys, Thr-5 --> Cys) or into putative TM II (Ser-71 --> Cys, Glu-75 --> Cys)
are highly accessible to membrane permeant and impermeant thiol reagents in
intact cells. In contrast, Cys at the C terminus (Ser-502 --> Cys) reacts only
with the membrane permeant but not with the impermeant reagent in intact cells.
These results contradict the 12-helix motif and indicate a periplasmic location
of the N terminus whereas the C terminus faces the cytoplasm. In addition, a
transporter with Cys in place of Leu-37 (putative periplasmic loop (pL2) shows
the same accessibility pattern as the Cys at the C terminus. Furthermore, PutP
which has been purified and reconstituted into proteoliposomes in an inside-out
orientation, is readily cleaved by the endoproteinase AspN before Asp-33 (pL2),
Asp-112 (putative cytoplasmic loop (cL3), Asp-262 (cL7), and Asp-356 (cL9). These
results suggest a cytosolic location of Asp-33 and Leu-37, thereby implying the
formation of an additional TM formed by amino acids of pL2. Based on these
observations, a new secondary structure model is proposed according to which the
protein consists of 13 TMs with the N terminus on the outside and the C terminus
facing the cytoplasm. The 13-helix structure is discussed as a common topological
motif for all members of the Na+/solute cotransporter family.
PMID- 9756873
TI - Human aggrecan keratan sulfate undergoes structural changes during adolescent
development.
AB - Alkaline borohydride-reduced keratan sulfate chains were isolated from human
articular cartilage aggrecan from individuals of various ages (0-85 years old).
The chains were structurally characterized using 1H NMR spectroscopy, gel
permeation chromatography, and oligosaccharide profiling (after digestion with
the enzymes keratanase and keratanase II). The results show that from birth to
early adolescence (0-9 years) the levels of alpha(1-3)-fucosylation, alpha(2-3)
sialylation, and galactose sulfation increase. Also, the weight-average molecular
weight of the chains increases. During maturation (9-18 years) the levels of
fucosylation and galactose sulfation continue to increase and alpha(2-6)
sialylation of the chains occurs. In adult life (18-85 years) there is little
change in the weight-average molecular weight of the chains, and the levels of
fucosylation, sialylation, and sulfation remain fairly constant.
PMID- 9756874
TI - Individual substitutions of clustered arginine residues of the sensor kinase KdpD
of Escherichia coli modulate the ratio of kinase to phosphatase activity.
AB - Escherichia coli responds to K+ limitation or high osmolarity by induction of the
kdpFABC operon coding for the high affinity K+-translocating Kdp-ATPase. KdpD,
the sensor kinase of this system, is a bifunctional enzyme catalyzing the
autophosphorylation by ATP and the dephosphorylation of the corresponding
response regulator KdpE. Here we demonstrate that individual replacements of
clustered arginine residues located close to transmembrane domain TM4 modulate
the ratio of kinase to phosphatase activity. Thus KdpD-Arg511 --> Gln is
characterized by an increase in the kinase activity and a loss of the phosphatase
activity. However, when Arg at position 511 is replaced with Lys, activities of
the corresponding protein are comparable with wild-type KdpD. In contrast,
replacement of arginine residues at positions 503, 506, or 508 with glutamine or
lysine causes a decrease of the kinase and an increase of the phosphatase
activities. Changes of the activities of these KdpD proteins correspond with
alterations in kdpFABC expression. Thus KdpD-Arg511 --> Gln causes constitutive
expression of kdpFABC. KdpD proteins with Arg replacements at positions 503, 506,
or 508 are unable to respond to osmolarity, whereas the sensing of K+ limitation
is not influenced. Simultaneous replacement of arginine residues 508 and 511 or
506, 508, and 511 with glutamine leads to a decrease of the phosphatase activity.
However, kdpFABC expression is dependent on K+ and osmolarity. Finally, when
Arg513 is replaced with glutamine the amount of KdpD detected in the membrane is
drastically reduced. These results imply that there is an equilibrium between the
kinase and phosphatase activities of KdpD, which can be shifted by the
replacement of one arginine residue. An electrostatic switch mechanism within the
protein is proposed through which the ratio of kinase to phosphatase is
regulated. Finally, these results lend support to the notion that KdpD can be
activated by two distinct stimuli, K+ limitation and osmolarity.
PMID- 9756875
TI - Overexpression of protein targeting to glycogen (PTG) in rat hepatocytes causes
profound activation of glycogen synthesis independent of normal hormone- and
substrate-mediated regulatory mechanisms.
AB - Protein targeting to glycogen (PTG), also known as PPP1R5, is a widely expressed
member of a growing family of proteins that target protein phosphatase-1 (PP-1)
to glycogen particles. Because PTG also binds to glycogen synthase and
phosphorylase kinase, it has been suggested that it serves as a "scaffold" for
efficient activation of glycogen synthesis. However, very little is known about
the metabolic effects of PTG. In this study, we have used recombinant adenovirus
to overexpress PTG in primary rat hepatocytes, a cell type with high glycogenic
capacity. We find that overexpression of PTG potently activates glycogen
synthesis in cultured hepatocytes. Surprisingly, the glycogenic effect of PTG is
observed even in the complete absence of carbohydrates or insulin in the culture
medium. Furthermore, glycogenolytic agents such as forskolin or glucagon are
largely ineffective at activating glycogen degradation in PTG overexpressing
hepatocytes, even though large increases in cAMP levels are demonstrated. These
metabolic effects of PTG overexpression are accompanied by a 3.6-fold increase in
glycogen synthase activation state and a 40% decrease in glycogen phosphorylase
activity. Our results are consistent with a model in which PTG overexpression
"locks" the hepatocyte in a glycogenic mode, presumably via its ability to
promote interaction of enzymes of glycogen metabolism with PP-1.
PMID- 9756876
TI - Genetic probing of the stalk segments associated with M2 and M3 of the plasma
membrane H+-ATPase from Saccharomyces cerevisiae.
AB - The stalk region of the H+-ATPase from Saccharomyces cerevisiae has been proposed
to play a role in coupling ATP hydrolysis to proton transport. Genetic probing
was used to examine the role of stalk segments S2 and S3, associated with M2 and
M3, respectively. Saturation mutagenesis was used to explore the role of side
group character at position Ile183 in S2, at which an alanine substitution was
shown previously to partially uncouple the enzyme (Wang, G., Tamas, M. J., Hall,
M. J., Pascual-Ahuir, A., and Perlin, D. S. (1996) J. Biol. Chem. 271, 25438
25445). Diverse side group substitutions were tolerated at this position,
although three substitutions, I183N, I183R, and I183Y required second site
mutations at the C terminus of the enzyme for stabilization. Substitution of
glycine and proline at Ile183 resulted in lethal phenotypes, suggesting that the
backbone may be more important than side group at this position. Proline/glycine
mutagenesis was used to study additional sites in S2 and S3. The substitution of
proline at Gly186 resulted in a lethal phenotype, whereas substitutions in S3 of
proline or serine at Gly270 and proline or glycine at Thr287 resulted in viable
mutants. Mutations G270P and T287P resulted in mutant enzymes that produced
pronounced growth defects and ATP hydrolysis rates that were 35% and 60% lower
than wild type enzyme, respectively. The mutant enzymes transported protons at
rates consistent with their ATPase activity, suggesting that the growth defects
observed were due to a reduced rate of ATP hydrolysis and not to uncoupling of
proton transport. The prominent growth phenotypes produced by mutations G270P and
T287P permitted the isolation of suppressor mutations, which restored wild type
growth. Most of the suppressors either replaced the primary site mutation with
alanine or restored the wild type residue by ectopic recombination with PMA2,
both of which restore alpha-helical tendency. This study suggests that
maintaining alpha-helical character is essential to S2 and may play an important
role in S3.
PMID- 9756877
TI - Cloning and overexpression of glycosyltransferases that generate the
lipopolysaccharide core of Rhizobium leguminosarum.
AB - The lipopolysaccharide (LPS) core of the Gram-negative bacterium Rhizobium
leguminosarum is more amenable to enzymatic study than that of Escherichia coli
because much of it is synthesized from readily available sugar nucleotides. The
inner portion of the R. leguminosarum core contains mannose, galactose, and three
3-deoxy-D-manno-octulosonate (Kdo) residues, arranged in the order: lipid A
(Kdo)2-Man-Gal-Kdo-[O antigen]. A mannosyltransferase that uses GDP-mannose and
the conserved precursor Kdo2-[4'-32P]lipid IVA (Kadrmas, J. L., Brozek, K. A.,
and Raetz, C. R. H. (1996) J. Biol. Chem. 271, 32119-32125) is proposed to
represent a key early enzyme in R. leguminosarum core assembly. Conditions for
demonstrating efficient galactosyl- and distal Kdo-transferase activities are now
described using a coupled assay system that starts with GDP-mannose and Kdo2-[4'
32P]lipid IVA. As predicted, mannose incorporation precedes galactose addition,
which in turn precedes distal Kdo transfer. LPS core mutants with Tn5 insertions
in the genes encoding the putative galactosyltransferase (lpcA) and the distal
Kdo-transferase (lpcB) are shown to be defective in the corresponding in vitro
glycosylation of Kdo2-[4'-32P]lipid IVA. We have also discovered the new gene
(lpcC) that encodes the mannosyltransferase. The gene is separated by several
kilobase pairs from the lpcAB cluster. All three glycosyltransferases are carried
on cosmid pIJ1848, which contains at least 20 kilobase pairs of R. leguminosarum
DNA. Transfer of pIJ1848 into R. meliloti 1021 results in heterologous expression
of all three enzymes, which are not normally present in strain 1021. Expression
of the lpc genes individually behind the T7 promoter results in the production of
each R. leguminosarum glycosyltransferase in E. coli membranes in a catalytically
active form, demonstrating that lpcA, lpcB, and lpcC are structural genes.
PMID- 9756878
TI - Autoprocessing and peptide substrates for human herpesvirus 6 proteinase.
AB - Autoprocessing of the precursor form of human herpesvirus 6 (HHV-6) proteinase at
two sites (termed M and R) is required to generate the mature enzyme. Kinetic
constants were determined for the hydrolysis of a series of synthetic peptide
substrates by mature HHV-6 proteinase, purified to homogeneity. Truncation or
replacement of individual residues in peptides mimicking the R-site sequence,
indicated that the minimum length for effective hydrolysis by the viral enzyme
was P4-P3-P2-Ala*Ser-P2'-P3'-P4' and revealed the importance of the P1 Ala and P4
Tyr residues. Consequently, relevant (P1 or P4) mutations were introduced into
the precursor form of the proteinase and the ability of these altered proteins to
autoprocess was examined. Introduction of Val in place of the P1 Ala at the M
site essentially abrogated cleavage but mature HHV-6 proteinase was still
generated by cleavage at the R-site, indicating that processing of the M-site is
not a prerequisite for cleavage of the R-site in the precursor. At the R-site,
mutation of the P1 Ala, or of the preceding P4 Tyr residue, prevented processing
at the R-site in the precursor so that the mature form of HHV-6 proteinase was
not generated. The accumulated data suggest a possible new approach to the design
of inhibitors for therapeutic intervention in the life cycle of herpesviruses.
PMID- 9756879
TI - Electrogenic antiport activities of the Gram-positive Tet proteins include a
Na+(K+)/K+ mode that mediates net K+ uptake.
AB - Two Gram-positive Tet proteins, TetA(L) from Bacillus subtilis and TetK from a
Staphylococcus aureus plasmid, have previously been suggested to have multiple
catalytic modes and roles. These include: tetracycline (Tc)-metal/H+ antiport for
both proteins (Yamaguchi, A., Shiina, Y., Fujihira, E., Sawai, T., Noguchi, N.,
and Sasatsu, M. (1995) FEBS Lett. 365, 193-197; Cheng, J. Guffanti, A. A., Wang,
W., Krulwich, T. A., and Bechhofer, D. H. (1996) J. Bacteriol. 178, 2853-2860);
Na+(K+)/H+ antiport for both proteins (Cheng et al. (1996)); and an electrical
potential-dependent K+ leak mode for TetK and highly truncated segments thereof
that can facilitate net K+ uptake (Guay, G. G., Tuckman, M., McNicholas, P., and
Rothstein, D. M. (1993) J. Bacteriol. 175, 4927-4929). Studies of membrane
vesicles from Escherichia coli expressing low levels of complete and 3'-truncated
versions of tetA(L) or tetK, now show that the full-length versions of both
transporters catalyze electrogenic antiport and that demonstration of
electrogenicity depends upon use of a low chloride buffer for the assay. The K+
uptake mode, assayed via 86Rb+ uptake, was also catalyzed by both full-length
TetA(L) and TetK. This mode does not represent a potential-dependent leak. Such a
leak was not demonstrable in energized membrane vesicles. Rather, Rb+ uptake
occurred in right-side-out vesicles when the intravesicular space contained
either Na+ or K+ but not choline. If an outwardly directed gradient of Na+ or K+
was present, Rb+ uptake occurred without energization in vesicles from cells
transformed with a plasmid containing tetA(L) or tetK but not a control plasmid.
Experiments in which a comparable exchange was carried out in low chloride
buffers to which oxonol was added confirmed that the exchange was electrogenic.
Thus, the K+ uptake mode is proposed to be a mode of the electrogenic monovalent
cation/H+ antiport activity of TetA(L) and TetK in which K+ takes the place of
the external protons. Truncated TetK and TetA(L) failed to catalyze either Tc
metal/H+ or Na+/H+ antiport in energized everted vesicles. Truncated TetK, but
not TetA(L), did, however, exhibit modest, electrogenic Na+(K+)/Rb+ exchange as
well as a small, potential-dependent leak of Rb+. The C-terminal halves of the
TetA(L) and TetK proteins are thus required both for proton-coupled active
transport activities of the multifunctional transporter and, perhaps, for
minimizing cation leakiness.
PMID- 9756880
TI - Identification and characterization of the RNA chaperone activity of hepatitis
delta antigen peptides.
AB - In this study, we identified an activity of the hepatitis delta antigen that both
modulates the cis-cleaving activities of hepatitis delta virus (HDV) genomic RNA
fragments and facilitates the trans-cleavage reactions between hammerhead
ribozymes and the cognate substrates of various lengths in vitro. Hepatitis delta
antigen peptides exert their effect by accelerating the unfolding and refolding
of RNA molecules and by promoting strand annealing and strand dissociation. In
addition, the stimulatory effect of hepatitis delta antigen peptide on hammerhead
catalysis is observed whether the peptide is removed or not by phenol/chloroform
extraction prior to the initiation of trans-cleavage reaction. Therefore,
hepatitis delta antigen peptide acts as an RNA chaperone. The RNA chaperone
domain of hepatitis delta antigen overlaps with the coiled-coil domain that is
rich in lysine residues. The RNA binding domains of hepatitis delta antigen
previously identified are not required for the RNA chaperone activity identified
herein. The RNA chaperone activity of hepatitis delta antigen may be important
for the regulation of HDV replication in vivo.
PMID- 9756881
TI - Electrochemical and spectroscopic properties of the iron-sulfur flavoprotein from
Methanosarcina thermophila.
AB - An iron-sulfur flavoprotein (Isf) from the methanoarchaeaon Methanosarcina
thermophila, which participates in electron transfer reactions required for the
fermentation of acetate to methane, was characterized by electrochemistry and EPR
and Mossbauer spectroscopy. The midpoint potential (Em) of the FMN/FMNH2 couple
was -0.277 V. No flavin semiquinone was observed during potentiometric
titrations; however, low amounts of the radical were observed when Isf was
quickly frozen after reaction with CO and the CO dehydrogenase/acetyl-CoA
synthase complex from M. thermophila. Isf contained a [4Fe-4S]2+/1+ cluster with
g values of 2.06 and 1.93 and an unusual split signal with g values at 1.86 and
1.82. The unusual morphology was attributed to microheterogeneity among Isf
molecules. The Em value for the 2+/1+ redox couple of the cluster was -0.394 V.
Extracts from H2-CO2-grown Methanobacterium thermoautotrophicum cells catalyzed
either the H2- or CO-dependent reduction of M. thermophila Isf. In addition, Isf
homologs were found in the genomic sequences of the CO2-reducing methanoarchaea
M. thermoautotrophicum and Methanococcus jannaschii. These results support a
general role for Isf in electron transfer reactions of both acetate-fermenting
and CO2-reducing methanoarchaea. It is suggested that Isf functions to couple
electron transfer from ferredoxin to membrane-bound electron carriers, such as
methanophenazine and/or b-type cytochromes.
PMID- 9756883
TI - Sequential hydrolysis of ATP molecules bound in interacting catalytic sites of
Escherichia coli transcription termination protein Rho.
AB - Escherichia coli transcription termination protein Rho, an RNA-dependent ATPase,
disrupts transcription complexes, releasing RNA and allowing RNA polymerase to
recycle. Homohexameric Rho binds three molecules of MgATP in a single class of
catalytically competent sites. In rapid mix chemical quench experiments, when Rho
saturated with ATP was mixed with RNA and the reaction was quenched after various
times, hydrolysis of the three bound ATP molecules was not simultaneous. A
hydrolysis burst of one molecule of ATP per hexamer occurred at >300 s-1,
followed by steady-state hydrolysis at 30 s-1 per hexamer. The burst also shows
that a step following ATP hydrolysis is rate-limiting for overall catalysis and
requires communication among the three catalytic sites during net ATP hydrolysis.
The rate of hydrolysis of radiolabeled ATP when one labeled and two unlabeled ATP
molecules are bound indicates a sequential pattern of hydrolysis. Positive
cooperativity of catalysis occurs among the catalytic sites of Rho; when only one
ATP molecule is bound per hexamer, ATP hydrolysis upon addition of RNA is 30-fold
slower than when ATP is saturating. These behaviors are comparable to those of F1
type ATPases, with which Rho shares a number of structural features.
PMID- 9756882
TI - A point mutation (G338S) and its suppressor mutations affect both the pH response
of the NhaA-Na+/H+ antiporter as well as the growth phenotype of Escherichia
coli.
AB - pH controls the activity of the NhaA Na+/H+ antiporter of Escherichia coli. In
the present work we show that replacement of glycine 338 of NhaA with serine
(G338S) alleviates the pH control of the antiporter. Monitoring Na+-dependent
collapse of DeltapH, to assess antiporter activity in isolated membrane vesicles,
shows that the mutant protein is practically independent of pH, between pH 7 and
9, and even at pH 6 is 70% active. Similarly the purified reconstituted mutant
protein catalyzes pH-independent passive efflux of 22Na from proteoliposomes as
well as DeltapH-driven influx. Whereas the native NhaA in isolated membrane
vesicles is exposed to digestion by trypsin only above pH 7, the mutated protein
is degraded already at pH 6.5. DeltanhaA DeltanhaB cells transformed with a
plasmid encoding the pH-independent antiporter are sensitive to Na+ but not to K+
at alkaline pH, while growing in the presence of both ions at neutral pH. Several
possibilities that could explain the Na+ sensitivity of the mutant at alkaline pH
were excluded; Western analysis and measurement of Na+/H+ antiporter activity in
membrane vesicles, isolated from cells shifted to the non-permissive growth
conditions, showed neither reduced expression of G338S-NhaA nor defective
activity. The finding that the mutated protein is electrogenic led to the
retraction of the idea that the protein is active in vitro but not in vivo at
alkaline pH, when only Deltapsi exists in the cells. The Na+ concentration needed
for half-maximal activity of G338S in isolated everted membrane vesicles is
similar to that of the wild type. Therefore an increase in intracellular Na+ due
to a reduced antiporter affinity could not explain the results. It is suggested
that the loss of growth at alkaline pH in the presence of Na+ is due to the loss
of the pH control of the mutated NhaA. Indeed, in the four mutations suppressing
G338S phenotype, growth at alkaline pH was restored together with the pH
regulation of NhaA. Three of the four suppressor mutations cluster in helix IV,
whereas the original mutation is in helix XI, suggesting that the two helixes
interact.
PMID- 9756884
TI - Mechanism of angiotensin II-mediated regulation of fibronectin gene in rat
vascular smooth muscle cells.
AB - This study was performed to investigate a mechanism of angiotensin II (Ang II)
mediated activation of the fibronectin (FN) gene in rat vascular smooth muscle
cells. Actinomycin D and CV11974 completely inhibited Ang II-mediated increase in
FN mRNA levels. Inhibitors of protein kinase C (PKC), protein-tyrosine kinase
(PTK), phosphatidylinositol-specific phospholipase C, Ras, phosphatidylinositol 3
kinase, p70 S6 kinase, and Ca2+/calmodulin kinase also decreased Ang II-induced
activation of FN mRNA. In contrast, cycloheximide; PD123319; or inhibitors of Gi,
protein kinase A, or mitogen-activated protein kinase kinase did not affect the
induction. FN promoter contained a putative AP-1 binding site (rFN/AP-1; -463 to
437), and the results of a transient transfection and electrophoretic mobility
shift assay showed that Ang II enhanced rFN/AP-1 activity. CV11974 and inhibitors
of PKC or PTK suppressed Ang II-mediated increases in rFN/AP-1 activity, although
neither PD123319 nor a protein kinase A inhibitor affected the induction.
Furthermore, mutation of rFN/AP-1 that disrupted nuclear binding suppressed Ang
II-induced transcription in the native FN promoter (-1908 to +136) context. Thus,
Ang II activates transcription of the FN gene through the Ang II type 1 receptor
in vascular smooth muscle cells, at least in part, via the activation of AP-1 by
a signaling mechanism dependent on PKC and PTK.
PMID- 9756885
TI - Protein farnesyltransferase from Trypanosoma brucei. A heterodimer of 61- and 65
kda subunits as a new target for antiparasite therapeutics.
AB - We have previously shown that protein prenylation occurs in the Trypanosomatids
Trypanosoma brucei (T. brucei), Trypanosoma cruzi, and Leishmania mexicana and
that protein farnesyltransferase (PFT) activity can be detected in cytosolic
extracts of insect (procyclic) form T. brucei. A PFT that transfers the farnesyl
group from farnesyl pyrophosphate to a cysteine that is 4 residues upstream of
the C terminus of the Ras GTP-binding protein RAS1-CVIM has now been purified
60,000-fold to near homogeneity from procyclic T. brucei. By screening a mixture
of hexapeptides SSCALX (X is 20 different amino acids), it was found that SSCALM
binds to T. brucei PFT with sub-micromolar affinity, and affinity chromatography
using this peptide was a key step in the purification of this enzyme. On SDS
polyacrylamide gel electrophoresis, the enzyme migrates as a pair of bands with
apparent molecular masses of 61 and 65 kDa, and thus its subunits are
approximately 30% larger than those of the mammalian homolog. The 61-kDa band was
identified as the putative beta-subunit by photoaffinity labeling with a 32P
labeled analog of farnesyl pyrophosphate. Mimetics of the C-terminal tetrapeptide
of prenyl acceptors have been previously shown to inhibit mammalian PFT, and
these compounds also inhibit T. brucei PFT with affinities in the nanomolar to
micromolar range, although the structure-activity relationship is very different
for parasite versus mammalian enzyme. Unlike mammalian cells, the growth of
bloodstream T. brucei is completely inhibited by low micromolar concentrations of
two of the PFT inhibitors, and these compounds also block protein farnesylation
in cultured parasites. These compounds also potently block the growth of the
intracellular (amastigote) form of T. cruzi grown in fibroblast host cells. The
results suggest that protein farnesylation is a target for the development of
anti-trypanosomatid chemotherapeutics.
PMID- 9756886
TI - Purification, characterization, and kinetic mechanism of cyclin D1. CDK4, a major
target for cell cycle regulation.
AB - The cyclin D1.CDK4-pRb (retinoblastoma protein) pathway plays a central role in
the cell cycle, and its deregulation is correlated with many types of cancers. As
a major drug target, we purified dimeric cyclin D1.CDK4 complex to near
homogeneity by a four-step procedure from a recombinant baculovirus-infected
insect culture. We optimized the kinase activity and stability and developed a
reproducible assay. We examined several catalytic and kinetic properties of the
complex and, via steady-state kinetics, derived a kinetic mechanism with a
peptide (RbING) and subsequently investigated the mechanistic implications with a
physiologically relevant protein (Rb21) as the phosphoacceptor. The complex bound
ATP 130-fold tighter when Rb21 instead of RbING was used as the phosphoacceptor.
By using staurosporine and ADP as inhibitors, the kinetic mechanism of the
complex appeared to be a "single displacement or Bi-Bi" with Mg2+.ATP as the
leading substrate and phosphorylated RbING as the last product released. In
addition, we purified a cyclin D1-CDK4 fusion protein to homogeneity by a three
step protocol from another recombinant baculovirus culture and observed similar
kinetic properties and mechanisms as those from the complex. We attempted to
model staurosporine in the ATP-binding site of CDK4 according to our kinetic
data. Our biochemical and modeling data provide validation of both the complex
and fusion protein as highly active kinases and their usefulness in
antiproliferative inhibitor discovery.
PMID- 9756888
TI - Generation of specific deoxynojirimycin-type inhibitors of the non-lysosomal
glucosylceramidase.
AB - The existence of a non-lysosomal glucosylceramidase in human cells has been
documented (van Weely, S., Brandsma, M., Strijland, A., Tager, J. M., and Aerts,
J. M. F. G. (1993) Biochim. Biophys. Acta 1181, 55-62). Hypothetically, the
activity of this enzyme, which is localized near the cell surface, may influence
ceramide-mediated signaling processes. To obtain insight in the physiological
importance of the non-lysosomal glucosylceramidase, the availability of specific
inhibitors would be helpful. Here we report on the generation of hydrophobic
deoxynojirimycin (DNM) derivatives that potently inhibit the enzyme. The
inhibitors were designed on the basis of the known features of the non-lysosomal
glucosylceramidase and consist of a DNM moiety, an N-alkyl spacer, and a large
hydrophobic group that promotes insertion in membranes. In particular, N-(5
adamantane-1-yl-methoxy)pentyl)-DNM is a very powerful inhibitor of the non
lysosomal glucosylceramidase at nanomolar concentrations. At such concentrations,
the lysosomal glucocerebrosidase and alpha-glucosidase, the glucosylceramide
synthase, and the N-linked glycan-trimming alpha-glucosidases of the endoplasmic
reticulum are not affected.
PMID- 9756887
TI - Interaction of Hic-5, A senescence-related protein, with focal adhesion kinase.
AB - Hydrogen peroxide-inducible clone (Hic)-5 is induced during the senescent process
in human fibroblasts, and the overexpression of Hic-5 induces a senescence-like
phenotype. Structurally, Hic-5 and paxillin, a 68-kDa cytoskeletal protein, share
homology such as the LD motifs in the N-terminal half and the LIM domains in the
C-terminal half. Here we show that Hic-5 binds to focal adhesion kinase (FAK) by
its N-terminal domain, and is localized to focal adhesions by its C-terminal LIM
domains. However, Hic-5 is not tyrosine phosphorylated either by the coexpressed
FAK in COS cells or by integrin stimulation in 293T cells. Furthermore,
overexpression of Hic-5 results in a decreased tyrosine phosphorylation of
paxillin. These findings suggest that putative functions of Hic-5 are the
recruitment of FAK to focal adhesions and a competitive inhibition of tyrosine
phosphorylation of paxillin.
PMID- 9756889
TI - Constitutive and adaptive detoxification of nitric oxide in Escherichia coli.
Role of nitric-oxide dioxygenase in the protection of aconitase.
AB - Nitric oxide (NO.) is a naturally occurring toxin that some organisms adaptively
resist. In aerobic or anaerobic Escherichia coli, low levels of NO. exposure
inactivated the NO.-sensitive citric acid cycle enzyme aconitase, and
inactivation was more effective when the adaptive synthesis of NO.-defensive
proteins was blocked with chloramphenicol. Protection of aconitase in aerobically
grown E. coli was dependent upon O2, was potently inhibited by cyanide, and was
correlated with an induced rate of cellular NO. consumption. Constitutive and
adaptive cellular NO. consumption in aerobic cells was also dependent upon O2 and
inhibited by cyanide. Exposure of aerobic cells to NO. accordingly elevated the
activity of the O2-dependent and cyanide-sensitive NO. dioxygenase (NOD).
Anaerobic E. coli exposed to NO. or nitrate induced a modest O2-independent and
cyanide-resistant NO.-metabolizing activity and a more robust O2-stimulated
cyanide-sensitive activity. The latter activity was attributed to NOD. The
results support a role for NOD in the aerobic detoxification of NO. and suggest
functions for NOD and a cyanide-resistant NO. scavenging activity in anaerobic
cells.
PMID- 9756890
TI - A regulatory element of the human keratin 18 gene with AP-1-dependent promoter
activity.
AB - The human keratin 18 (K18) gene is expressed in a restricted but diverse subset
of differentiated epithelial tissues and carcinomas. The 10-kilobase pair K18
gene contains all of the genetic information necessary for tissue-specific, copy
number-dependent and integration site-independent expression in transgenic mice.
We identified a 100-base pair regulatory element that activates the K18 proximal
promoter in the presence of the previously identified first intron enhancer.
Deletion of the element greatly diminished K18 expression. This regulatory
element also has cryptic, AP-1-dependent promoter activity in the absence of the
normal promoter, which results in 10-40-fold higher levels of K18 RNA expression
in transgenic mice. The high activity of this cryptic promoter is dependent upon
the first intron enhancer. These experiments define interactive regulatory
regions of the K18 gene that modulate expression in diverse epithelial cell types
and identify an unusual regulatory element with promoter activity that may be
useful for high level heterologous gene expression in transgenic animals.
PMID- 9756891
TI - Guanine nucleotide exchange on ADP-ribosylation factors catalyzed by cytohesin-1
and its Sec7 domain.
AB - ADP-ribosylation factors (ARFs) are 20-kDa guanine nucleotide-binding proteins
that require specific guanine nucleotide-exchange proteins (GEPs) to accelerate
the conversion of inactive ARF-GDP to active ARF-GTP. Cytohesin-1, a 46-kDa ARF
GEP, contains a central Sec7 domain of 188 amino acids similar in sequence to a
region of the yeast Sec7 protein. Cytohesin-1 and its 22-kDa Sec7 domain (C-1
Sec7), synthesized in Escherichia coli, were assayed with recombinant non
myristoylated ARFs and related proteins to compare their GEP activities. Both
were effective with native mammalian ARFs 1 and 3. Cytohesin-1 accelerated
GTPgammaS (guanosine 5'-3-O-(thio)triphosphate) binding to recombinant human ARF1
(rARF1), yeast ARF3, and ARD1 (a 64-kDa guanine nucleotide-binding protein
containing a C-terminal ARF domain). In contrast, C-1 Sec7 enhanced GTPgammaS
binding to recombinant human ARFs 1, 5, and 6; yeast ARFs 1, 2, and 3; ARD1; two
ARD1 mutants that contain the ARF domain; and Delta13ARF1, which lacks the N
terminal alpha-helix. Neither C-1 Sec7 nor cytohesin-1 increased GTPgammaS
binding to human ARF-like ARL proteins 1, 2, and 3. Thus, ARLs, initially
differentiated from ARFs because of their inability to activate cholera toxin,
differ also in their failure to interact functionally with C-1 Sec7 or cytohesin
1. As C-1 Sec7 was much less substrate-specific than cytohesin-1, it appears that
structure outside of the Sec7 domain is important for ARF specificity. Data
obtained with mutant ARF constructs are all consistent with the conclusion that
the ARF N terminus is an important determinant of cytohesin-1 specificity.
PMID- 9756892
TI - Molecular basis of V2 vasopressin receptor/Gs coupling selectivity.
AB - The molecular mechanisms governing the coupling selectivity of G protein-coupled
receptors activated by peptide ligands are not well understood. To shed light on
this issue, we have used the Gq/11-linked V1a and the Gs-coupled V2 vasopressin
peptide receptors as model systems. To explore the structural basis underlying
the ability of the V2 receptor to selectively recognize Gs, we systematically
substituted distinct V2 receptor segments (or single amino acids) into the V1a
receptor and studied whether the resulting hybrid receptors gained the ability to
mediate hormone-dependent cAMP production. This strategy appeared particularly
attractive since hormone stimulation of the V1a receptor has virtually no effect
on intracellular cAMP levels. Functional analysis of a large number of mutant
receptors transiently expressed in COS-7 cells indicated that the presence of V2
receptor sequence at the N terminus of the third intracellular loop is critical
for efficient activation of Gs. More detailed mutational analysis of this
receptor region showed that two polar V2 receptor residues, Gln225 and Glu231,
play key roles in Gs recognition. In addition, a short sequence at the N terminus
of the cytoplasmic tail was found to make an important contribution to V2
receptor/Gs coupling selectivity. We also made the novel observation that the
efficiency of V2 receptor/Gs coupling can be modulated by the length of the
central portion of the third intracellular loop (rather than the specific amino
acid sequence within this domain). These findings provide novel insights into the
molecular mechanisms regulating peptide receptor/G protein coupling selectivity.
PMID- 9756893
TI - Tra1p is a component of the yeast Ada.Spt transcriptional regulatory complexes.
AB - The yeast Ada and TBP class of Spt proteins interact in multiple complexes that
are required for transcriptional regulation. We have identified Tra1p as a
component of these complexes through tandem mass spectrometry analysis of
proteins that associate with Ngg1p/Ada3p. TRA1 is an essential gene and encodes a
3744-amino acid protein that is a member of a group of proteins including the
catalytic subunit of DNA-dependent protein kinase, ATM and TRRAP, with carboxyl
terminal regions related to phosphatidylinositol 3-kinases. The interaction
between Tra1p and Ada/Spt components was verified by the reciprocal
coimmunoprecipitation of Ada2p and Tra1p from whole cell extracts in one or more
complexes containing Spt7p. Tra1p cofractionated with Ngg1p and Spt7p through
consecutive chromatography on Mono Q, DNA-cellulose, and Superose 6 columns.
Binding of Tra1p to DNA-cellulose required Ada components. The association of
Tra1p with two Ada.Spt complexes was suggested by its cofractionation with Ngg1p
and Spt7p in two peaks on the Mono Q column. In the absence of Ada2p, the elution
profile of Tra1p shifted to a distinct peak. Despite the similarity of Tra1p to a
group of putative protein kinases, we have not detected protein kinase activity
within immunoprecipitates of Tra1p or the Ada.Spt complexes.
PMID- 9756894
TI - Conversion of procaspase-3 to an autoactivating caspase by fusion to the caspase
2 prodomain.
AB - Caspases are cysteine proteases that play an essential role in apoptosis. Initial
activation of caspases defines the key step in apoptotic execution. Based on
primary structure, caspases can be divided into two groups, those with long amino
terminal prodomains (class I), and those with relatively short prodomains (class
II). On overexpression in mammalian cells, class I caspases can induce cell death
that is dependent on their autocatalytic activity. Recent studies suggest that
the long prodomains in some class I caspases are able to mediate dimerization of
procaspase molecules, thereby promoting autoprocessing. In this communication, we
demonstrate that fusion of the prodomain of a class I caspase (Nedd2/caspase-2)
with procaspase-3 greatly augments autocatalysis and apoptosis induction by the
chimeric caspase-3 molecule. The chimeric caspase-3 molecules were able to form
homodimers in Saccharomyces cerevisiae and were efficiently processed in
transfected mammalian cells. These results provide direct evidence for a role of
a class I caspase prodomain in caspase autoactivation and processing and
establish a basis for functional hierarchy among the two classes of caspases.
PMID- 9756895
TI - Characterization of the chicken CTCF genomic locus, and initial study of the cell
cycle-regulated promoter of the gene.
AB - CTCF is a multifunctional transcription factor encoded by a novel candidate tumor
suppressor gene (Filippova, G. N., Lindblom, A., Meinke, L. J., Klenova, E. M.,
Neiman, P. E., Collins, S. J., Doggett, N. D., and Lobanenkov, V. V. (1998) Genes
Chromosomes Cancer 22, 26-36). We characterized genomic organization of the
chicken CTCF (chCTCF) gene, and studied the chCTCF promoter. Genomic locus of
chCTCF contains a GC-rich untranslated exon separated from seven coding exons by
a long intron. The 2-kilobase pair region upstream of the major transcription
start site contains a CpG island marked by a "Not-knot" that includes sequence
motifs characteristic of a TATA-less promoter of housekeeping genes. When fused
upstream of a reporter chloramphenicol acetyltransferase gene, it acts as a
strong transcriptional promoter in transient transfection experiments. The
minimal 180-base pair chCTCF promoter region that is fully sufficient to confer
high level transcriptional activity to the reporter contains high affinity
binding element for the transcription factor YY1. This element is strictly
conserved in chicken, mouse, and human CTCF genes. Mutations in the core
nucleotides of the YY1 element reduce transcriptional activity of the minimal
chCTCF promoter, indicating that the conserved YY1-binding sequence is critical
for transcriptional regulation of vertebrate CTCF genes. We also noted in the
chCTCF promoter several elements previously characterized in cell cycle-regulated
genes, including the "cell cycle-dependent element" and "cell cycle gene homology
region" motifs shown to be important for S/G2-specific up-regulation of cdc25C,
cdc2, cyclin A, and Plk (polo-like kinase) gene promoters. Presence of the cell
cycle-dependent element/cell cycle gene homology region element suggested that
chCTCF expression may be cell cycle-regulated. We show that both levels of the
endogenous chCTCF mRNA, and the activity of the stably transfected chCTCF
promoter constructs, increase in S/G2 cells.
PMID- 9756896
TI - Site-specific core 1 O-glycosylation pattern of the porcine submaxillary gland
mucin tandem repeat. Evidence for the modulation of glycan length by peptide
sequence.
AB - The sequence-specific O-linked core 1 ([R1, R2]-beta-Gal(1-3)-alpha-GalNAc-O
Ser/Thr) glycosylation pattern has been quantitatively determined for 30 of the
31 Ser/Thr residues in the 81-residue porcine submaxillary gland mucin tandem
repeat. This was achieved by Edman amino acid sequencing of the isolated tandem
repeat after selective removal of non-C3-substituted, peptide-linked GalNAc
residues by periodate oxidation and subsequent trimming of the remaining
oligosaccharides to peptide-linked GalNAc residues by mild
trifluoromethanesulfonic acid/anisole treatment. The sequencing reveals 61%
(range, 12-95%) of the peptide alpha-N-acetylgalactosamine (GalNAc) residues to
be substituted by core 1 chains, a value in agreement with the carbon-13 NMR
analysis of the native mucin. Residues with the lowest C3 substitution were
typically clustered in regions of sequence with the highest densities of
(glycosylated) serine or threonine. This suggests that the porcine beta3-Gal,
core 1, transferase is sensitive to peptide sequence and/or neighboring core
GalNAc glycosylation in vivo, in keeping with earlier in vitro enzymatic
glycosylation studies (Granovsky, M., Blielfeldt, T., Peters, S., Paulsen, H.,
Meldal, M., Brockhausen, J., and Brockhausen, I. (1994) Eur. J. Biochem. 221,
1039-1046). These results demonstrate that the O-glycan structures in mucin
domains are not necessarily uniformly distributed along the polypeptide core and
that their lengths can be modulated by peptide sequence. The data further suggest
that hydroxyamino acid spacing may contribute to the regulation of glycan length,
thereby, providing a mechanism for maintaining an optimally expanded, protease
resistant, mucin conformation.
PMID- 9756897
TI - Identification of inhibitors of prohormone convertases 1 and 2 using a peptide
combinatorial library.
AB - A positional scanning synthetic peptide combinatorial library containing
approximately 52 million hexapeptides was used to identify potential inhibitory
peptides for recombinant mouse prohormone convertase 1 (PC1) and PC2 and to
provide information on the specificity of these enzymes. The library surveys
revealed that a P6 Leu, a P4 Arg, a P2 Lys, and a P1 Arg were most inhibitory
against PC1, and a P6 Ile and a P4 Arg were most inhibitory against PC2. Using
information derived from the library surveys, hexapeptide sets were synthesized
and screened for inhibition of PC1 and PC2. The data obtained revealed the
preference of both enzymes for a P3 Val. At P5, many substitutions were well
tolerated. PC1 and PC2 proved to differ mainly in the selectivity of their S6
subsites. In PC1, this subsite displayed a strong preference toward occupation by
Leu; the Ki value for peptide Ac-Leu-Leu-Arg-Val-Lys-Arg-NH2 was 28 times lower
than that for peptide Ac-Ile-Ile-Arg-Val-Lys-Arg-NH2. In contrast, PC2
discriminated little between Leu and Ile at P6, as evidenced by the small (1.5
fold) difference in Ki values for these two peptides. Several hexapeptides
synthesized as a result of the screen were found to represent potent inhibitors
of PC2 (with Ki values in the submicromolar range) and, particularly, of PC1
(with Ki values in the low nanomolar range). The most potent inhibitor, Ac-Leu
Leu-Arg-Val-Lys-Arg-NH2, proved to be the same peptide for both enzymes and
inhibited PC1 and PC2 in a competitive, fast-binding manner with Ki values of 3.2
and 360 nM, respectively. The four most potent peptide inhibitors of PC1 and PC2
were also tested against soluble human furin and found to exhibit a different
rank order of inhibition; for example, Ac-Leu-Leu-Arg-Val-Lys-Arg-NH2 was 440
fold less potent against furin than against PC1, with a Ki of 1400 nM.
PMID- 9756898
TI - N-Methyl-D-aspartate inhibits apoptosis through activation of
phosphatidylinositol 3-kinase in cerebellar granule neurons. A role for insulin
receptor substrate-1 in the neurotrophic action of n-methyl-D-aspartate and its
inhibition by ethanol.
AB - Primary cultured rat cerebellar granule neurons underwent apoptosis when switched
from medium containing 25 mM K+ to one containing 5 mM K+. N-methyl-D-aspartate
(NMDA) protected granule neurons from apoptosis in medium containing 5 mM K+.
Inhibition of apoptosis by NMDA was blocked by the phosphatidylinositol 3-kinase
(PI 3-kinase) inhibitor LY294002, but it was unaffected by the mitogen-activated
protein kinase kinase inhibitor PD 98059. The antiapoptotic action of NMDA was
associated with an increase in the tyrosine phosphorylation of insulin receptor
substrate 1 (IRS-1), an increase in the binding of the regulatory subunit of PI 3
kinase to IRS-1, and a stimulation of PI 3-kinase activity. In the absence of
extracellular Ca2+, NMDA was unable to prevent apoptosis or to phosphorylate IRS
1 and activate PI 3-kinase. Significant inhibition of NMDA-mediated neuronal
survival by ethanol (10-15%) was observed at 1 mM, and inhibition was half
maximal at 45-50 mM. Inhibition of neuronal survival by ethanol corresponded with
a marked reduction in the capacity of NMDA to increase the concentration of
intracellular Ca2+, phosphorylate IRS-1, and activate PI 3-kinase. These data
demonstrate that the neurotrophic action of NMDA and its inhibition by ethanol
are mediated by alterations in the activity of a PI 3-kinase-dependent
antiapoptotic signaling pathway.
PMID- 9756899
TI - The role of residue 238 of TEM-1 beta-lactamase in the hydrolysis of extended
spectrum antibiotics.
AB - beta-Lactamases inactivate beta-lactam antibiotics by catalyzing the hydrolysis
of the amide bond in the beta-lactam ring. The plasmid-encoded class A TEM-1 beta
lactamase is a commonly encountered beta-lactamase. It is able to inactivate
penicillins and cephalosporins but not extended-spectrum antibiotics. However,
TEM-1-derived natural variants containing the G238S amino acid substitution
display increased hydrolysis of extended-spectrum antibiotics. Two models have
been proposed to explain the role of the G238S substitution in hydrolysis of
extended-spectrum antibiotics. The first proposes a direct hydrogen bond of the
Ser238 side chain to the oxime group of extended-spectrum antibiotics. The second
proposes that steric conflict with surrounding residues, due to increased side
chain volume, leads to a more accessible active site pocket. To assess the
validity of each model, TEM-1 mutants with amino acids substitutions of Ala, Ser,
Cys, Thr, Asn, and Val have been constructed. Kinetic analysis of these enzymes
with penicillins and cephalosporins suggests that a hydrogen bond is necessary
but not sufficient to achieve the hydrolytic activity of the G238S enzyme for the
extended-spectrum antibiotics cefotaxime and ceftazidime. In addition, it appears
that the new hydrogen bond interaction is to a site on the enzyme rather than
directly to the extended-spectrum antibiotic. The data indicate that, for the
G238S substitution, a combination of an optimal side chain volume and hydrogen
bonding potential results in the most versatile and advantageous antibiotic
hydrolytic spectrum for bacterial resistance to extended-spectrum antibiotics.
PMID- 9756900
TI - Mechanism of action of RNA polymerase II elongation factor Elongin. Maximal
stimulation of elongation requires conversion of the early elongation complex to
an Elongin-activable form.
AB - We previously identified and purified Elongin by its ability to stimulate the
rate of elongation by RNA polymerase II in vitro (Bradsher, J. N., Jackson, K.
W., Conaway, R. C., and Conaway, J. W. (1993) J. Biol. Chem. 268, 25587-25593).
In this report, we present evidence that stimulation of elongation by Elongin
requires that the early RNA polymerase II elongation complex undergoes conversion
to an Elongin-activable form. We observe (i) that Elongin does not detectably
stimulate the rate of promoter-specific transcription initiation by the fully
assembled preinitiation complex and (ii) that early RNA polymerase II elongation
intermediates first become susceptible to stimulation by Elongin after
synthesizing 8-9-nucleotide-long transcripts. Furthermore, we show that the
relative inability of Elongin to stimulate elongation by early elongation
intermediates correlates not with the lengths of their associated transcripts
but, instead, with the presence of transcription factor IIF (TFIIF) in
transcription reactions. By exploiting adenovirus 2 major late promoter
derivatives that contain premelted transcriptional start sites and do not require
TFIIF, TFIIE, or TFIIH for transcription initiation, we observe (i) that Elongin
is capable of strongly stimulating the rate of synthesis of trinucleotide
transcripts by a subcomplex of RNA polymerase II, TBP, and TFIIB and (ii) that
the ability of Elongin to stimulate synthesis of these short transcripts is
substantially reduced by addition of TFIIF to transcription reactions. Here we
present these findings, which are consistent with the model that maximal
stimulation of elongation by Elongin requires that early elongation intermediates
undergo a structural transition that includes loss of TFIIF.
PMID- 9756901
TI - Molecular analysis of two pyruvate dehydrogenase kinases from maize.
AB - Two maize cDNAs were isolated and sequenced that had open reading frames with
approximately 37% amino acid identity to mammalian pyruvate dehydrogenase
kinases. Both maize kinase sequences contain the five domains with conserved
signature residues typical of procaryotic two-component histidine kinases.
Sequence comparisons identified six other highly conserved motifs that are
proposed to be specific to pyruvate dehydrogenase kinases. In addition, specific
Trp and Cys residues are also invariant in these sequences. The maize cDNAs are
1332 (PDK1) and 1602 (PDK2) nucleotides in length, encoding polypeptides with
calculated molecular masses of 38,867 and 41,327 Da that share 77% amino acid
identity. Reverse transcriptase-polymerase chain reaction analysis with
oligonucleotide-specific primers revealed a differential expression pattern for
the two isoforms. PDK1 and PDK2 were expressed in Escherichia coli with N
terminal His6 tags to facilitate purification. The recombinant proteins migrated
at 44 and 48 kDa, respectively, during SDS-polyacrylamide gel electrophoresis.
Anti-PDK1 antibodies immunoprecipitated 75% of pyruvate dehydrogenase kinase
activity from a maize mitochondrial matrix fraction, and recognized a matrix
protein of 43 kDa. Recombinant PDK2, expressed as a fusion with the maltose
binding protein, inactivated kinase-depleted maize pyruvate dehydrogenase complex
when incubated with MgATP, coincident with incorporation of 32P from [gamma
32P]ATP into the alpha subunit of pyruvate dehydrogenase.
PMID- 9756902
TI - Functional assignment by Chimera construction of the domain affecting
heterotropic activation of deoxyadenosine kinase from Lactobacillus acidophilus R
26.
AB - The heterodimeric subunits of deoxyadenosine kinase (dAK)-deoxyguanosine kinase
(dGK) from Lactobacillus acidophilus R-26 exhibit contrasting conformations
manifested in the nearly unidirectional heterotropic activation of dAK when dGK
binds deoxyguanosine. This is mediated, in part, by the conserved Ras switch I
like sequence (residues 153-161) [Guo et al. (1997) J. Biol. Chem. 272, 6890
6897]. In an attempt to identify domains differentiating the specificities of dAK
and dGK, we constructed several chimeras splicing heterodimeric dAK within this
region. In Chimera-III, dAK residues 120-170 were replaced by the homologous
section of dGK. dAK activity was elevated 40%, but although it retained its
original specificity and Km values, it could no longer be activated by
deoxyguanosine. Moreover, both the activated dAK and the "dAK" of Chimera-III
exhibited (i) an increased Ks for the leading substrate ATP-Mg2+, suggesting the
formation of intermediate enzyme species along their respective kinetic pathways,
and (ii) broadened and lower pH optima for the dAK activities. These observations
further indicate the importance of dAK residues 120-170, including the Ras-like
segment, in catalysis and heterotropic activation. The other conformational
properties of dAK (e.g. self-inactivity and MgATP being the leading substrate)
were unaltered by this substitution, thus localizing the responsible domains even
further upstream.
PMID- 9756903
TI - Auxin-induced stress potentiates trans-activation by a conserved plant
basic/leucine-zipper factor.
AB - The promoter element activation sequence-1 (as-1) confers tissue-specific and
signal-responsive transcription in plants. Hormone and chemical stress cues are
thought to activate as-1-dependent transcription through specific basic/leucine
zipper proteins, termed TGA factors, that bind this element. We report here that
a highly conserved TGA factor of tobacco, TGA1a, can selectively activate
transcription in response to micromolar concentrations of auxin hormones or their
analogs. This induction is chemically specific, as a range of other compounds
tested at similar concentrations had little or no effect. Auxin was found to
augment the trans-activation potential of TGA1a through carboxyl-terminal
residues. The amino-terminal domain of TGA1a, by gain-of-function assays, was
found to both constitutively activate transcription and maximize the response to
auxin. Further evidence indicates that the trans-activation potential of this
domain in TGA1a is repressed, under basal conditions, by carboxyl-terminal
residues. Because TGA1a and endogenous TGA factors are stimulated by auxin only
at concentrations that inhibited cell growth, this response is likely to involve
chemical stress.
PMID- 9756905
TI - Solution structure of the epsilon subunit of the F1-ATPase from Escherichia coli
and interactions of this subunit with beta subunits in the complex.
AB - The solution structure of the epsilon subunit of the Escherichia coli F1-ATPase
has been determined by NMR spectroscopy. This subunit has a two-domain structure
with an N-terminal 10-stranded beta sandwich and a C-terminal antiparallel two
alpha-helix hairpin, as described previously (Wilkens, S., Dahlquist, F. W.,
McIntosh, L. P., Donaldson, L. W., and Capaldi, R. A. (1995) Nat. Struct. Biol.
2, 961-967). New data show that the two domains interact in solution in an
interface formed by beta strand 7 and the very C-terminal alpha-helix. This
interface involves only hydrophobic interactions. The dynamics of the epsilon
subunit in solution were examined. The two domains are relatively tightly
associated with little or no flexibility relative to one another. The epsilon
subunit can exist in two states in the ECF1F0 complex depending on whether ATP or
ADP occupies catalytic sites. Proteolysis of the epsilon subunit in solution and
when bound to the core F1 complex indicates that the conformation of the
polypeptide in solution closely resembles the conformation of epsilon when bound
to the F1 in the ADP state. Chemical and photo-cross-linking show that the
epsilon subunit spans and interacts with two beta subunits in the ADP state.
These interactions are disrupted on binding of ATP + Mg2+, as is the interaction
between the N- and C-terminal domains of the epsilon subunit.
PMID- 9756904
TI - The role of phosphoinositide 3-kinase in taurocholate-induced trafficking of ATP
dependent canalicular transporters in rat liver.
AB - Recent studies indicate that wortmannin, a potent inhibitor of
phosphatidylinositol (PI) 3-kinase, interferes with bile acid secretion in rat
liver; taurocholate induces recruitment of ATP-dependent transporters to the bile
canalicular membrane, and PI 3-kinase products are important in intracellular
trafficking. We investigated the role of PI 3-kinase in bile acid secretion by
studying the in vivo effect of taurocholate, colchicine, and wortmannin on bile
acid secretion, kinase activity, and protein levels in canalicular membrane
vesicle (CMV) and sinusoidal membrane vesicle (SMV) fractions from rat liver.
Treatment of rats or perfusion of isolated liver with taurocholate significantly
increased PI 3-kinase activity in both membrane fractions. Taurocholate increased
protein content of ATP-dependent transporters, which were detected only in CMVs,
whereas increased levels of p85 and a cell adhesion molecule, cCAM 105, were
observed in both fractions. Colchicine prevented taurocholate-induced changes in
all proteins studied, as well as the increase in PI 3-kinase activity in CMVs,
but it resulted in further accumulation of PI 3-kinase activity, p85, and cCAM
105 in SMVs. These results indicate that taurocholate-mediated changes involve a
microtubular system. Wortmannin blocked taurocholate-induced bile acid secretion.
The effect was more profound when wortmannin was administered prior to treatment
with taurocholate. When wortmannin was given after taurocholate, the protein
levels of each ATP-dependent transporter were maintained in CMVs, whereas the
levels of p85 and cCAM decreased in both membrane fractions. Perfusion of liver
with wortmannin before taurocholate administration blocked accumulation of all
proteins studied in CMVs and SMVs. These results indicate that PI 3-kinase is
required for intracellular trafficking of itself, as well as of ATP-dependent
canalicular transporters.
PMID- 9756906
TI - Activation of the prolactin gene by peroxisome proliferator-activated receptor
alpha appears to be DNA binding-independent.
AB - Although the effects of the peroxisome proliferator-activated receptors (PPARs)
have been studied primarily in adipocytes and liver, the wide distribution of
these receptors suggests that they might also play a role in other cell types. We
present evidence that PPAR activators stimulate the expression of the prolactin
gene in pituitary GH4C1 cells. Transfection assays in non-pituitary HeLa cells
showed that stimulation of the prolactin promoter by PPARalpha requires the
presence of the transcription factor GHF-1 (or Pit-1). Proximal promoter
sequences confer responsiveness to PPARalpha, and activation by this receptor is
lost concomitantly with the response to GHF-1. Surprisingly, expression of the
retinoid X receptor (RXR) abolishes stimulation by PPARalpha. Furthermore, the
promoter region that confers PPARalpha responsiveness does not contain a PPAR
response element. This suggests that the transcriptional effect of PPARalpha
might be mediated by protein-protein interactions rather than by binding of
PPAR/RXR to the promoter. A direct interaction between PPARalpha and GHF-1 was
confirmed by in vitro binding studies. Expression of the coactivators SRC-1 and
CREB-binding protein, which bind to PPAR, also enhanced the responsiveness of the
prolactin promoter to PPARalpha. Furthermore, CREB-binding protein also
significantly increased activation by GHF-1, and both proteins associated in
vitro. Thus, PPARalpha, a receptor that normally acts as a ligand-dependent
transcription factor by binding to specific DNA sequences in one context, can
also stimulate the prolactin promoter by association with GHF-1 and coactivator
proteins.
PMID- 9756907
TI - Characterization of distinct human endometrial carcinoma cell lines deficient in
mismatch repair that originated from a single tumor.
AB - The role of specific mismatch repair (MMR) gene products was examined by
observing several phenotypic end points in two MMR-deficient human endometrial
carcinoma cell lines that were originally isolated from the same tumor. The first
cell line, HEC-1-A, contains a nonsense mutation in the hPMS2 gene, which results
in premature termination and a truncated hPMS2 protein. In addition, HEC-1-A
cells carry a splice mutation in the hMSH6 gene and lack wild-type hMSH6 protein.
The second cell line, HEC-1-B, possesses the same defective hMSH6 locus. However,
HEC-1-B cells are heterozygous at the hPMS2 locus; that is, along with carrying
the same nonsense mutation in hPMS2 as in HEC-1-A, HEC-1-B cells also contain a
wild-type hPMS2 gene. Initial recognition of mismatches in DNA requires either
the hMSH2/hMSH6 or hMSH2/hMSH3 heterodimer, with hPMS2 functioning downstream of
damage recognition. Therefore, cells defective in hPMS2 should completely lack
MMR (HEC-1-A), whereas cells mutant in hMSH6 only (HEC-1-B) can potentially
repair damage via the hMSH2/hMSH3 heterodimer. The data presented here in HEC-1-B
cells illustrate (i) the reduction of instability at microsatellite sequences,
(ii) a significant decrease in frameshift mutation rate at HPRT, and (iii) the in
vitro repair of looped substrates, relative to HEC-1-A cells, illustrating the
repair of frameshift intermediates by hMSH2/hMSH3 heterodimer. Furthermore, the
role of hMSH2/hMSH3 heterodimer in the repair of base:base mismatches is
supported by observing the reduction in base substitution mutation rate at HPRT
in HEC-1-B cells (hMSH6-defective but possessing wild-type hPMS2), as compared
with HEC-1-A (hMSH6/hPMS2-defective) cells. These data support a critical role
for hPMS2 in human MMR, while further defining the role of the hMSH2/hMSH3
heterodimer in maintaining genomic stability in the absence of a wild-type
hMSH2/hMSH6 heterodimer.
PMID- 9756908
TI - Release of thioredoxin via the mechanosensitive channel MscL during osmotic
downshock of Escherichia coli cells.
AB - Escherichia coli cells possess several mechanosensitive ion channels but only
MscL, the channel with the highest conductance, which is activated at the highest
membrane tension, has been cloned. We investigated the putative involvement of
MscL in the effluxes caused by osmotic downshock. Osmotic shock caused the
release of potassium glutamate, trehalose, and glycine betaine from wild type
cells and cells lacking MscL. There was no difference between the two strains,
but the extreme rapidity of the efflux process, as shown herein for glycine
betaine, suggests that it is channel-mediated. Osmotic downshock also induces the
release of some cytosolic proteins from EDTA-treated cells. We investigated the
release of thioredoxin. This protein was totally released from wild type cells
but was retained by MscL- cells. Release was restored by expression of the gene
coding for MscL. Thus MscL is not necessary for the excretion of osmoprotectants,
but it does open in vivo during shock and catalyzes the efflux of thioredoxin and
possibly other small cytosolic proteins. It follows that the other
mechanosensitive channels, which are known to be activated at lower tension, must
also open during osmotic shock. Their opening and that of MscL could account for
the rapid release of osmolytes.
PMID- 9756909
TI - Identification of three major sentrinization sites in PML.
AB - Acute promyelocytic leukemia arises following a reciprocal chromosome
translocation t(15;17), which generates PML-retinoic acid receptor alpha fusion
proteins (PML-RARalpha). We have shown previously that wild type PML, but not PML
RARalpha, is covalently modified by the sentrin family of ubiquitin-like proteins
(Kamitani, T., Nguyen, H. P., Kito, K., Fukuda-Kamitani, T., and Yeh, E. T. H.
(1998) J. Biol. Chem. 273, 3117-3120). To understand the mechanisms underlying
the differential sentrinization of PML versus PML-RARalpha, extensive mutational
analysis was carried out to determine which Lys residues are sentrinized. We show
that Lys65 in the RING finger domain, Lys160 in the B1 Box, and Lys490 in the
nuclear localization signal contributes three major sentrinization sites. The PML
mutant with Lys to Arg substitutions in all three sites is expressed normally,
but cannot be sentrinized. Furthermore, the triple substitution mutant is
localized predominantly to the nucleoplasm, in contrast to wild type PML, which
is localized to the nuclear bodies. Thus, sentrinization of PML, in the context
of the RING finger and the B1 box, regulates nuclear body formation. Furthermore,
we showed that sentrinization of PML-RARalpha could be restored by overexpression
of sentrin, but not by retinoic acid treatment. These studies provide novel
insight into the pathobiochemistry of acute promyelocytic leukemia and the
sentrinization pathway.
PMID- 9756910
TI - Characterization of a 190-kilobase pair domain of human type I hair keratin
genes.
AB - Polymerase chain reaction-based screening of an arrayed human P1 artificial
chromosome (PAC) library using primer pairs specific for the human type I hair
keratins hHa3-II or hHa6, led to the isolation of two PAC clones, which covered
190 kilobase pairs (kbp) of genomic DNA and contained nine human type I hair
keratin genes, one transcribed hair keratin pseudogene, as well as one orphan
exon. The hair keratin genes are 4-7 kbp in size, exhibit intergenic distances of
5-8 kbp, and display the same direction of transcription. With one exception, all
hair keratin genes are organized into 7 exons and 6 positionally conserved
introns. On the basis of sequence homologies, the genes can be grouped into three
subclusters of tandemly arranged genes. One subcluster harbors the highly related
genes hHa1, hHa3-I, hHa3-II, and hHa4. A second subcluster of highly related
genes comprises the novel genes hHa7 and hHa8, as well as pseudogene PsihHaA,
while the structurally less related genes hHa6, hHa5, and hHa2 are constituents
of the third subcluster. As shown by reverse transcription-polymerase chain
reaction, all hair keratin genes, including the pseudogene, are expressed in the
human hair follicle. The transcribed pseudogene PsihHaA contains a premature stop
codon in exon 4 and exhibits aberrant pre-mRNA splicing. Evolutionary tree
construction reveals an early divergence of hair keratin genes from cytokeratin
genes, followed by the segregation of the genes into the three subclusters. We
suspect that the 190-kbp domain contains the entire complement of human type I
hair keratin genes.
PMID- 9756911
TI - Physiological and pathological secretion of cartilage oligomeric matrix protein
by cells in culture.
AB - Abnormalities in cartilage oligomeric matrix protein (COMP), a pentameric
structural protein of the cartilage extracellular matrix, have been identified in
pseudoachondroplasia and multiple epiphyseal dysplasia, two human autosomal
dominant osteochondrodysplasias. However, the function of the protein remains
unknown. With the goal of establishing a model to study the mechanisms by which
COMP mutations cause disease, we have analyzed synthesis and secretion of COMP in
cultured chondrocytes, tendon, and ligament cells. Pentameric protein detected
inside of control cells suggested that pentamerization is an intracellular
process. Patient cells expressed mutant and normal RNA and secreted COMP at
levels similar to controls, suggesting that abnormal pentamers are likely to be
found in the extracellular matrix. Inclusions within patient cartilage stained
with anti-COMP antibodies, and cultured cells presented similar inclusions,
indicating that presumably abnormal COMP pentamers are less efficiently secreted
than normal molecules. We conclude that the COMP disorders are likely to result
from a combination of a decreased amount of COMP in the matrix and a dominant
negative effect due to the presence of abnormal pentamers in cartilage.
PMID- 9756912
TI - RP58 associates with condensed chromatin and mediates a sequence-specific
transcriptional repression.
AB - An approximately 120-amino acid domain present generally at the NH2 termini,
termed the POZ domain, is highly conserved in various proteins with zinc finger
DNA binding motifs. We have isolated a novel protein sharing homology with the
POZ domain of a number of zinc finger proteins, including the human BCL-6
protein. By using a binding site selection technique (CAST), a high affinity
binding site of the protein was determined to be (A/C)ACATCTG(G/T)(A/C),
containing the E box core sequence motif. The protein was shown to repress
transcription from a promoter linked to its target sequences and was hence named
RP58 (Repressor Protein with a predicted molecular mass of 58 kDa). Immunogold
electron microscopic study revealed that almost all RP58 is localized in
condensed chromatin regions. These observations demonstrate for the first time
that a protein mediating a sequence-specific transcriptional repression
associates with highly condensed chromatin. We suggest that RP58 may be involved
in a molecular link between sequence-specific transcriptional repression and the
organization of chromosomes in the nucleus.
PMID- 9756913
TI - A pathway where polyprenyl diphosphate elongates in prenyltransferase. Insight
into a common mechanism of chain length determination of prenyltransferases.
AB - Prenyltransferases catalyze the consecutive condensations of isopentenyl
diphosphate to produce linear polyprenyl diphosphates. Each enzyme forms the
final product with a specific chain length. The product specificity of an enzyme
is thought to be determined by the structure around the unknown path through
which the product elongates in the enzyme. To explore the path, we introduced a
few mutations at the 5th, the 8th, and/or the 11th positions before the first
aspartate-rich motif of geranylgeranyl-diphosphate synthase or farnesyl
diphosphate synthase. The side chains of these amino acids are situated on the
same side of an alpha-helix. In geranylgeranyl-diphosphate synthase, a single
mutated enzyme (F77S) mainly produces a C25 product (Ohnuma, S.-I., Hirooka, K.,
Hemmi, H., Ishida, C., Ohto, C., and Nishino, T. (1996) J. Biol. Chem. 271, 18831
18837). A double mutated enzyme (L74G and F77G) mainly produces a C35 compound
with significant amounts of C30 and C40. A triple mutated enzyme (I71G, L74G, and
F77G) mainly produces a C40 compound with C35 and C45. Mutated farnesyl
diphosphate synthases also show similar patterns. These findings indicate that
the elongating product passages on a surface of the side chains of the mutated
amino acids, the original bulky amino acids had blocked the elongation, and the
path is conserved in prenyltransferases. Moreover, the fact that some double and
triple mutated enzymes can also form small amounts of products longer than C50
indicates that the paths in these mutated enzymes can partially access the outer
surface of the enzymes.
PMID- 9756914
TI - X-ray analysis of the NMC-A beta-lactamase at 1.64-A resolution, a class A
carbapenemase with broad substrate specificity.
AB - The treatment of infectious diseases by penicillin and cephalosporin antibiotics
is continuously challenged by the emergence and the dissemination of the numerous
TEM and SHV mutant beta-lactamases with extended substrate profiles. These class
A beta-lactamases nevertheless remain inefficient against carbapenems, the most
effective antibiotics against clinically relevant pathogens. A new member of this
enzyme class, NMC-A, was recently reported to hydrolyze at high rates, and hence
destroy, all known beta-lactam antibiotics, including carbapenems and
cephamycins. The crystal structure of NMC-A was solved to 1.64-A resolution, and
reveals modifications in the topology of the substrate-binding site. While
preserving the geometry of the essential catalytic residues, the active site of
the enzyme presents a disulfide bridge between residues 69 and 238, and certain
other structural differences compared with the other beta-lactamases. These
unusual features in class A beta-lactamases involve amino acids that participate
in enzyme-substrate interactions, which suggested that these structural factors
should be related to the very broad substrate specificity of this enzyme. The
comparison of the NMC-A structure with those of other class A enzymes and enzyme
ligand complexes, indicated that the position of Asn-132 in NMC-A provides
critical additional space in the region of the protein where the poorer
substrates for class A beta-lactamases, such as cephamycins and carbapenems, need
to be accommodated.
PMID- 9756915
TI - Extracellular signal-regulated protein kinase/Jun kinase cross-talk underlies
vascular endothelial cell growth factor-induced endothelial cell proliferation.
AB - Ligand binding to vascular endothelial cell growth factor (VEGF) receptors
activates the mitogen-activated protein kinases extracellular signal-regulated
kinase (ERK) and c-Jun N-terminal protein kinase (JNK). Possible cross
communication of ERK and JNK effecting endothelial cell (EC) actions of VEGF is
poorly understood. Incubation of EC with PD 98059, a specific mitogen-activated
protein kinase kinase inhibitor, or transfection with Y185F, a dominant negative
ERK2, strongly inhibited VEGF-activated JNK. JNK was also activated by ERK2
expression in the absence of VEGF, inhibited 82% by co-transfection with dominant
negative SEK-1, indicating upstream activation of JNK by ERK. VEGF-stimulated JNK
activity was also reversed by dominant negative SEK-1. Other EC growth factors
exhibited similar cross-activation of JNK through ERK. VEGF stimulated the
nuclear incorporation of thymidine, reversed 89% by PD 98059 and 72% by Y185F.
Dominant negative SEK-1 or JNK-1 also significantly reduced VEGF-stimulated
thymidine incorporation. Expression of wild type Jip-1, which prevents JNK
nuclear translocation, inhibited VEGF-induced EC proliferation by 75%. VEGF
stimulated both cyclin D1 synthesis and Cdk4 kinase activity, inhibited by PD
98059 and dominant negative JNK-1. Important events for VEGF-induced G1/S
progression and cell proliferation are enhanced through a novel ERK to JNK cross
activation and subsequent JNK action.
PMID- 9756916
TI - Expression cloning and characterization of a novel murine alpha1, 3
fucosyltransferase, mFuc-TIX, that synthesizes the Lewis x (CD15) epitope in
brain and kidney.
AB - The 3-fucosyl-N-acetyllactosamine (Lewis x, CD15, SSEA-1) carbohydrate epitope is
widely distributed in many tissues and is developmentally expressed in some
rodent and human tissues, i.e. brain and lung, and mouse early embryo. In such
tissues, the Lewis x epitope is considered to be involved in cell-cell
interactions. We isolated a novel mouse alpha1,3-fucosyltransferase gene, named
mFuc-TIX, from an adult mouse brain cDNA library using the expression cloning
method. On flow cytometric analysis, Namalwa cells transfected stably with the
mFuc-TIX gene showed a marked increase in Lewis x epitopes but not sialyl Lewis x
epitopes. As seen experiments involving oligosaccharides as acceptor substrates,
mFuc-TIX transfers a fucose to lacto-N-neotetraose but not to either alpha2,3
sialyl lacto-N-neotetraose or lacto-N-tetraose. The substrate specificity of mFuc
TIX was similar to that of mouse myeloid-type alpha1,3-fucosyltransferase (mFuc
TIV). The deduced amino acid sequence of mFuc-TIX, consisting of 359 residues,
indicated a type II membrane protein and shows low degrees of homology to the
previously cloned alpha1,3-fucosyltransferases, i.e. mFuc-TIV (48.4%), mouse Fuc
TVII (39.1%), and human Fuc-TIII (43.0%), at the amino acid sequence level. A
phylogenetic tree of the alpha1, 3-fucosyltransferases constructed by the
neighbor-joining method showed that mFuc-TIX is quite distant from the other
alpha1, 3-fucosyltransferases. Thus, mFuc-TIX does not belong to any subfamilies
of known alpha1,3Fuc-Ts. The mFuc-TIX transcript was mainly detected in brain and
kidney with the Northern blotting and competitive reverse transcription
polymerase chain reaction methods, whereas the mFuc-TIV transcript was not
detected in brain with these methods. On in situ hybridization, the mFuc-TIX
transcript was detected in neuronal cells but not in the glial cells including
astrocytes. These results strongly indicated that mFuc-TIX participates in the
Lewis x synthesis in neurons of the brain and may be developmentally regulated.
PMID- 9756917
TI - Dissecting cAMP binding domain A in the RIalpha subunit of cAMP-dependent protein
kinase. Distinct subsites for recognition of cAMP and the catalytic subunit.
AB - The two gene-duplicated cAMP binding domains in the regulatory subunits of cAMP
dependent protein kinase are each comprised of an A helix, an eight-stranded beta
barrel, and a B and C helix (1). The A domain is required for high affinity
binding to C, while the B domain regulates access to the A domain. Using a
combination of a yeast two-hybrid screen coupled with deletion analysis, cAMP
binding domain A of RI was dissected into two structurally and functionally
distinct subsites, one that binds cAMP and another that binds the C subunit. The
minimum stable subdomain required for binding to C in the 1-3 micromolar range is
composed of residues 94-169, while residues 236-244, mapped to the C helix of
cAMP binding domain A, were defined as a second surface necessary for high
affinity (5-10 nanomolar) binding to C. This portion of the C helix, due to its
position directly between the two subsites, serves as a molecular switch for
either a cAMP-bound conformation or a C-bound conformation and can thus modulate
interactions of cAMP binding domain A with cAMP, with C, and with cAMP binding
domain B.
PMID- 9756918
TI - Identification of a form of acyl-CoA:cholesterol acyltransferase specific to
liver and intestine in nonhuman primates.
AB - The present study demonstrates that two different forms of the intracellular
cholesterol esterification enzyme acyl-CoA:cholesterol acyltransferase (ACAT) are
present in the nonhuman primate hepatocyte; one is similar to that originally
cloned from human genomic DNA, here termed ACAT1, while a second gene product,
termed ACAT2, is reported here. The primate ACAT2 gene product was cloned from an
African green monkey liver cDNA library. Sequence analysis of an isolated, full
length clone of ACAT2 cDNA identified an open reading frame encoding a 526-amino
acid protein with essentially no sequence similarity to the ACAT1 cDNA over the N
terminal 101 amino acids but with 57% identity predicted over the remaining 425
amino acids. Transfection of the cloned ACAT2 cDNA into two different mammalian
cell types resulted in the production of abundant ACAT activity which was
sensitive to ACAT inhibitors. Northern blot analysis showed that the ACAT2 mRNA
was expressed primarily in liver and intestine in monkeys. In contrast, ACAT1
mRNA was expressed in almost all tissues examined. Topologic predictions from the
amino acid sequence of ACAT2 indicates that it has seven trans-membrane domains
in a configuration that places the putative active site of the enzyme in the
lumen of the endoplasmic reticulum. This orientation of ACAT2 in the endoplasmic
reticulum membrane, in addition to its expression only in liver and intestine,
suggests that this enzyme may have as a primary function, the secretion of
cholesteryl esters into apoB-containing lipoproteins.
PMID- 9756919
TI - ACAT-2, a second mammalian acyl-CoA:cholesterol acyltransferase. Its cloning,
expression, and characterization.
AB - The synthesis of cholesterol esters by acyl-CoA:cholesterol acyltransferase
(ACAT, EC 2.3.1.26) is an important component of cellular cholesterol
homeostasis. Cholesterol ester formation also is hypothesized to be important in
several physiologic processes, including intestinal cholesterol absorption,
hepatic lipoprotein production, and macrophage foam cell formation in
atherosclerotic lesions. Mouse tissue expression studies and the disruption of
the mouse ACAT gene (Acact) have indicated that more than one ACAT exists in
mammals and specifically that another enzyme is important in mouse liver and
intestine. We now describe a second mammalian ACAT enzyme, designated ACAT-2,
that is 44% identical to the first cloned mouse ACAT (henceforth designated ACAT
1). Infection of H5 insect cells with an ACAT-2 recombinant baculovirus resulted
in expression of a approximately 46-kDa protein in cell membranes that was
associated with high levels of cholesterol esterification activity. Both ACAT-1
and ACAT-2 also catalyzed the esterification of the 3beta-hydroxyl group of a
variety of oxysterols. Cholesterol esterification activities for ACAT-1 and ACAT
2 exhibited different IC50 values when assayed in the presence of several ACAT
specific inhibitors, demonstrating that ACAT inhibitors can selectively target
specific forms of ACAT. ACAT-2 was expressed primarily in mouse liver and small
intestine, supporting the hypothesis that ACAT-2 contributes to cholesterol
esterification in these tissues. The mouse ACAT-2 gene (Acact2) maps to
chromosome 15 in a region containing a quantitative trait locus influencing
plasma cholesterol levels. The identification and cloning of ACAT-2 will
facilitate molecular approaches to understanding the role of ACAT enzymes in
mammalian biology.
PMID- 9756920
TI - Characterization of two human genes encoding acyl coenzyme A:cholesterol
acyltransferase-related enzymes.
AB - The enzyme acyl coenzyme A:cholesterol acyltransferase 1 (ACAT1) mediates sterol
esterification, a crucial component of intracellular lipid homeostasis. Two
enzymes catalyze this activity in Saccharomyces cerevisiae (yeast), and several
lines of evidence suggest multigene families may also exist in mammals. Using the
human ACAT1 sequence to screen data bases of expressed sequence tags, we
identified two novel and distinct partial human cDNAs. Full-length cDNA clones
for these ACAT related gene products (ARGP) 1 and 2 were isolated from a
hepatocyte (HepG2) cDNA library. ARGP1 was expressed in numerous human adult
tissues and tissue culture cell lines, whereas expression of ARGP2 was more
restricted. In vitro microsomal assays in a yeast strain deleted for both
esterification genes and completely deficient in sterol esterification indicated
that ARGP2 esterified cholesterol while ARGP1 did not. In contrast to ACAT1 and
similar to liver esterification, the activity of ARGP2 was relatively resistant
to a histidine active site modifier. ARGP2 is therefore a tissue-specific sterol
esterification enzyme which we thus designated ACAT2. We speculate that ARGP1
participates in the coenzyme A-dependent acylation of substrate(s) other than
cholesterol. Consistent with this hypothesis, ARGP1, unlike any other member of
this multigene family, possesses a predicted diacylglycerol binding motif
suggesting that it may perform the last acylation in triglyceride biosynthesis.
PMID- 9756921
TI - Activation of cyclin-dependent kinase 2 (Cdk2) in growth-stimulated rat
astrocytes. Geranylgeranylated Rho small GTPase(s) are essential for the
induction of cyclin E gene expression.
AB - The role of the mevalonate cascade in the control of cell cycle progression in
astrocytes has been investigated. Serum stimulation of rat astrocytes in primary
culture induces the expression of cyclin E followed by the activation of cyclin
dependent kinase 2 (Cdk2) during G1/S transition. The expression of p27, cyclin
D1, and the activities of Cdk4 and Cdk-activating kinase (CAK), composed of Cdk7
and cyclin H, were not affected. Serum did, however, stimulate the expression of
3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase mRNA at mid-G1 phase.
Moreover, an inhibitor of HMG-CoA reductase, pravastatin, reduced cyclin E
expression and Cdk2 activation and caused G1 arrest in the astrocytes. In
contrast, mevalonate and its metabolite, geranylgeranylpyrophosphate (GGPP) but
not farnesylpyrophosphate (FPP), reversed the inhibitory effects of pravastatin
on cyclin E expression and Cdk2 activation and allowed G1/S transition. Rho small
GTPase(s) were geranylgeranylated and translocated to membranes in the presence
of GGPP during G1/S transition. The effect of GGPP on cyclin E expression was
abolished by botulinum C3 exoenzyme, which specifically inactivates Rho. These
data indicate that geranylgeranylated Rho small GTPase(s) are essential for the
induction of cyclin E expression, Cdk2 activation, and G1/S transition in rat
astrocytes.
PMID- 9756922
TI - Single glycosyltransferase, core 2 beta1-->6-N-acetylglucosaminyltransferase,
regulates cell surface sialyl-Lex expression level in human pre-B lymphocytic
leukemia cell line KM3 treated with phorbolester.
AB - Sialyl-Lex (sLex) antigen expression recognized by KM93 monoclonal antibody was
significantly down-regulated during differentiation induced by 12-O
tetradecanoylphorbol-13-acetate (TPA) in human pre-B lymphocytic leukemia cell
line KM3. The sLex determinants were almost exclusively expressed on O-linked
oligosaccharide chains of an O-glycosylated 150-kDa glycoprotein (gp150). A low
shear force cell adhesion assay showed that TPA treatment significantly inhibited
E-selectin-mediated cell adhesion. Transcript and/or enzyme activity levels of
alpha1-->3-fucosyltransferase, alpha2-->3-sialyltransferase, beta1-->4
galactosyltransferase, and elongation beta1-->3-N-acetylglucosaminyltransferase
did not correlate with sLex expression levels. However, transcript and enzyme
activity levels of core 2 GlcNAc-transferase (C2GnT) were significantly down
regulated during TPA treatment. Following transfection and constitutive
expression of full-length exogenous C2GnT transcript, C2GnT enzyme activities
were maintained at high levels even after TPA treatment and down-regulation of
cell surface sLex antigen expression by TPA was completely abolished.
Furthermore, in the transfected cells, the KM93 reactivity of gp150 was not
reduced by TPA treatment, and the inhibition of cell adhesion by TPA was also
blocked. These results suggest that sLex expression is critically regulated by a
single glycosyltransferase, C2GnT, during differentiation of KM3 cells.
PMID- 9756923
TI - Molecular analysis of the interactions between protein kinase C-epsilon and
filamentous actin.
AB - Protein kinase C-epsilon (PKC-epsilon) contains a putative actin binding motif
that is unique to this individual member of the PKC gene family. We have used
deletion mutagenesis to determine whether this hexapeptide motif is required for
the physical association of PKC-epsilon and actin. Full-length recombinant PKC
epsilon, but not PKC-betaII, -delta, -eta, or -zeta, bound to filamentous actin
in a phorbol ester-dependent manner. Deletion of PKC-epsilon amino acids 222-230,
encompassing a putative actin binding motif, completely abrogated this binding
activity. When NIH 3T3 cells overexpressing either PKC-epsilon or the deletion
mutant of this isozyme were treated with phorbol ester only wild-type PKC-epsilon
colocalized with actin in zones of cell adhesion. In binary reactions, it was
possible to demonstrate that purified filamentous actin is capable of directly
stimulating PKC-epsilon phosphotransferase activity. These and other findings
support the hypothesis that a conformationally hidden actin binding motif in the
PKC-epsilon sequence becomes exposed upon activation of this isozyme and
functions as a dominant localization signal in NIH 3T3 fibroblasts. This protein
protein interaction is sufficient to maintain PKC-epsilon in a catalytically
active conformation.
PMID- 9756925
TI - Human inter-alpha-trypsin inhibitor heavy chain H3 gene. Genomic organization,
promoter analysis, and gene linkage.
AB - To understand more about the human inter-alpha-trypsin inhibitor heavy chain H3
(ITIH3) expression and the relationship between this gene and the family of other
ITI heavy chain genes, an analysis of the structure of the ITIH3 gene and its
promoter region was performed. This gene is a single copy gene, 14 kilobase pair
in length and consists of 22 exons. ITIH3 shares highly conserved exon size and
intron-exon borders with other ITI heavy chain genes. We determined that the
human ITIH1, ITIH3, and ITIH4 genes are closely linked within a 45-kilobase pair.
They are arranged in the order of H1-H3-H4, with the ITIH4 gene transcribed in
the opposite direction. A model for the evolution of the ITI heavy chain gene
family is presented that involves multiple rounds of gene duplication plus
inversion events. The minimum promoter region (-135 to +75) is identified in
HepG2 cells. The transient transfection study in various cell lines indicates
that the activity of the ITIH3 promoter is not liver-specific. DNase I
footprinting, mobility shift assays, and cotransfection experiments reveal a
functional CCAAT/enhancer-binding protein site (C/EBP, -1344 to -1305) which
interacts with C/EBPalpha and C/EBPbeta factors. The latter factors control the
transcription of the ITIH3 gene positively.
PMID- 9756924
TI - Expression and trans-synaptic regulation of P2x4 and P2z receptors for
extracellular ATP in parotid acinar cells. Effects of parasympathetic
denervation.
AB - Trans-synaptic regulation of muscarinic, peptidergic, and purinergic responses
after denervation has been reported previously in rat parotid acinar cells
(McMillian, M. K., Soltoff, S. P., Cantley, L. C., Rudel, R., and Talamo, B. R.
(1993) Br. J. Pharmacol. 108, 453-461). Characteristics of the ATP-mediated
responses and the effects of parasympathetic denervation were further analyzed
through assay of Ca2+ influx, using fluorescence ratio imaging methods, and by
analysis of P2x receptor expression. ATP activates both a high affinity and a low
affinity response with properties corresponding to the recently described P2x4
and the P2z (P2x7)-type purinoceptors, respectively. Reverse transcription
polymerase chain reaction analysis reveals mRNA for P2x4 as well as P2x7 subtypes
but not P2x1, P2x2, P2x3, P2x5, or P2x6. P2x4 protein also is detected by Western
blotting. Distribution of the two types of ATP receptor responses on individual
cells was stochastic, with both high and low affinity responses on some cells,
and only a single type of response on others. Sensitivity to P2x4-type activation
also varied even among cells responsive to low concentrations of ATP.
Parasympathetic denervation greatly enhanced responses, tripling the proportion
of acinar cells with a P2x4-type response and increasing the fraction of highly
sensitive cells by 7-fold. Moreover, P2x4 mRNA is significantly increased
following parasympathetic denervation. These data indicate that sensitivity to
ATP is modulated by neurotransmission at parasympathetic synapses, at least in
part through increased expression of P2x4 mRNA, and suggest that similar
regulation may occur at other sites in the nervous system where P2x4 receptors
are widely expressed.
PMID- 9756926
TI - Light-dependent activation of rod transducin by pineal opsin.
AB - The pineal gland expresses a unique member of the opsin family (P-opsin; Max, M.,
McKinnon, P. J., Seidenman, K. J., Barrett, R. K., Applebury, M. L., Takahashi,
J. S., and Margolskee, R. F. (1995) Science 267, 1502-1506) that may play a role
in circadian entrainment and photo-regulation of melatonin synthesis. To study
the function of this protein, an epitope-tagged P-opsin was stably expressed in
an embryonic chicken pineal cell line. When incubated with 11-cis-retinal, a
light-sensitive pigment was formed with a lambdamax at 462 +/- 2 nm. P-opsin
bleached slowly in the dark (t1/2 = 2 h) in the presence of 50 mM hydroxylamine.
Purified P-opsin in dodecyl maltoside activated rod transducin in a light
dependent manner, catalyzing the exchange of more than 300 mol of GTPgammaS
(guanosine 5'-O-(3-thiotriphosphate))/mol of P-opsin. The initial rate for
activation (75 mol of GTPgammaS bound/mol of P-opsin/min at 7 microM) increased
with increasing concentrations of transducin. The addition of egg
phosphatidylcholine to P-opsin had little effect on the activation kinetics;
however, the intrinsic rate of decay in the absence of transducin was
accelerated. These results demonstrate that P-opsin is an efficient catalyst for
activation of rod transducin and suggest that the pineal gland may contain a
rodlike phototransduction cascade.
PMID- 9756927
TI - Substrate binding induces depolymerization of the C-terminal peptide binding
domain of murine GRP78/BiP.
AB - To investigate the role of each domain in BiP/GRP78 function, we have used a full
length recombinant BiP engineered to contain two enterokinase sites; one site is
located after an N-terminal FLAG epitope, and a second site has been inserted at
the junction between the N- and C-terminal domains (FLAG-BiP.ent). FLAG-BiP.ent
oligomerizes into multiple species that interconvert with each other in a slow,
concentration- and temperature-dependent equilibrium. Binding of ATP or AMP-PNP
(adenosine 5'-(beta, gamma-imino)triphosphate), but not ADP, or of a peptidic
substrate induces depolymerization of FLAG-BiP.ent and stabilization of monomeric
species. Enterokinase cleavage of monomeric, nucleotide-free BiP.ent results in
the physical dissociation of the 44-kDa N-terminal ATPase fragment (N44.ent) from
the 30-kDa C-terminal substrate binding domain (C30.ent). Upon dissociation, the
freed C-terminal substrate binding domain readily undergoes self-association
while N44.ent remains monomeric. Enterokinase cleavage performed in the presence
of a synthetic peptide prevents oligomerization of the freed C30.ent domain.
Addition of ATP during enterokinase cleavage has no effect on C30.ent
oligomerization. Our data clearly indicate that binding of a specific peptide
onto the C-terminal domain, or ATP onto the N-terminal domain, induces internal
conformational change(s) within the C30 domain that result(s) in BiP
depolymerization.
PMID- 9756928
TI - Identification of the MNN2 and MNN5 mannosyltransferases required for forming and
extending the mannose branches of the outer chain mannans of Saccharomyces
cerevisiae.
AB - The mannan structure found on the N-linked glycans of the yeast Saccharomyces
cerevisiae is composed of a long backbone of alpha-1, 6-linked mannose to which
are attached branches consisting of two alpha-1,2-linked mannoses followed by an
alpha-1,3-linked mannose. In the mutants mnn2 and mnn5, the addition of the first
and second of these two mannoses, respectively, is defective. In this paper, we
report the identification of the genes corresponding to these mutations. The two
genes encode closely related proteins with distant homology to the known Mnn1p
alpha-1,3-mannosyltransferase. We show that these proteins are localized in an
early compartment of the yeast Golgi and that they are not physically associated
with each other or with the two protein complexes known to be involved in
synthesizing the alpha-1,6-linked backbone. The identification of Mnn2p and Mnn5p
allows us to assign Golgi proteins to all of the catalytic steps in S. cerevisiae
mannan synthesis.
PMID- 9756929
TI - Functional analysis of human mitochondrial receptor Tom20 for protein import into
mitochondria.
AB - The mitochondrial import receptor translocase of the outer membrane of
mitochondria (Tom20) consists of five segments, an N-terminal membrane-anchor
segment, a linker segment rich in charged amino acids, a tetratricopeptide repeat
motif, a glutamine-rich segment, and a C-terminal segment. To assess the role of
each segment, four C-terminally truncated mutants of the human receptor (hTom20)
were constructed, and the effect of their overexpression in COS-7 cells was
analyzed. Expression of a mutant lacking the tetratricopeptide repeat motif
inhibited preornithine transcarbamylase (pOTC) import to the same extent as the
wild-type receptor. Thus, overexpression of the membrane-anchor and the linker
segments is sufficient for the inhibition of import. Expression of either the
wild-type receptor or a mutant lacking the C-terminal end of 20 amino acid
residues stimulated import of pOTC-green fluorescent protein (GFP), a fusion
protein in which the presequene of pOTC was fused to green fluorescent protein.
On the other hand, expression of mutants lacking either the glutamine-rich
segment or larger deletions inhibited pOTC-GFP import. In vitro import of pOTC
was inhibited by the wild-type hTom20 and the mutant lacking the C-terminal end,
but much less strongly by the mutant lacking the glutamine-rich segment. On the
other hand, import of pOTC-GFP was little affected by any of the forms of hTom20.
In binding assays, pOTC binding to hTom20 was only moderately decreased by the
deletion of the glutamine-rich segment, whereas pOTC-GFP binding was completely
lost by this deletion. Binding of pOTCN-GFP a construct that contains an
additional 58 N-terminal residues of mature OTC, resembled that of pOTC. All of
these results indicate that the region 106-125 containing the glutamine-rich
segment of hTom20 is essential for binding and import stimulation in vivo of pOTC
GFP and for inhibition of in vitro import of pOTC. The results also indicate that
this region is important for mitochondrial aggregation. The different behaviors
of pOTC and the pOTC-GFP chimera toward hTom20 mutants is explicable on the basis
of the conformation of the precursor proteins.
PMID- 9756930
TI - Activation of human endothelial cells via S-endo-1 antigen (CD146) stimulates the
tyrosine phosphorylation of focal adhesion kinase p125(FAK).
AB - S-Endo-1 antigen (CD146), a transmembrane receptor also known as MUC18/MCAM, is a
member of the immunoglobulin superfamily and belongs to a group of cell adhesion
molecules. CD146 is highly expressed on the whole vascular tree. We demonstrate
here that engagement of CD146 on human endothelial cells isolated from cord blood
results in tyrosine phosphorylation of a large panel of cellular proteins,
although no tyrosine phosphorylation of CD146 was detected. In particular, CD146
cross-linking induces the tyrosine phosphorylation of the protein tyrosine kinase
p125(FAK) as well as p125(FAK) association with paxillin, both events being
inhibited by cytochalasin D. No direct association of CD146 with p125(FAK) was
observed. Consistent with these data, CD146 associates with p59(fyn), a Src
family kinase known to phosphorylate p125(FAK). The identification of a signaling
pathway initiated by CD146 engagement and which includes p59(fyn), p125(FAK), and
paxillin indicates that CD146 participates in outside-in signaling in endothelial
cells.
PMID- 9756931
TI - Unique mode of GCC box recognition by the DNA-binding domain of ethylene
responsive element-binding factor (ERF domain) in plant.
AB - Ethylene-responsive element-binding proteins (EREBPs)have novel DNA-binding
domains (ERF domains), which are widely conserved in plants, and interact
specifically with sequences containing AGCCGCC motifs (GCC box). Deletion
experiments show that some flanking region at the N terminus of the conserved 59
amino acid ERF domain is required for stable binding to the GCC box. Three ERF
domain-containing fragments of EREBP2, EREBP4, and AtERF1 from tobacco and
Arabidopsis, bind to the sequence containing the GCC box with a high binding
affinity in the pM range. The high affinity binding is conferred by a monomeric
ERF domain fragment, and DNA truncation experiments show that only 11-base pair
DNA containing the GCC box is sufficient for stable ERF domain interaction.
Systematic DNA mutation analyses demonstrate that the specific amino acid
contacts are confined within the 6-base pair GCCGCC region of the GCC box, and
the first G, the fourth G, and the sixth C exhibit highest binding specificity
common in all three ERF domain-containing fragments studied. Other bases within
the GCC box exhibit modulated binding specificity varying from protein to
protein, implying that these positions are important for differential binding by
different EREBPs. The conserved N-terminal half is likely responsible for
formation of a stable complex with the GCC box and the divergent C-terminal half
for modulating the specificity.
PMID- 9756932
TI - Tyrosine-based membrane protein sorting signals are differentially interpreted by
polarized Madin-Darby canine kidney and LLC-PK1 epithelial cells.
AB - Tyrosine-dependent sequence motifs are implicated in sorting membrane proteins to
the basolateral domain of Madin-Darby canine kidney (MDCK) cells. We find that
these motifs are interpreted differentially in various polarized epithelial cell
types. The H, K-ATPase beta subunit, which contains a tyrosine-based motif in its
cytoplasmic tail, was expressed in MDCK and LLC-PK1 cells. This protein was
restricted to the basolateral membrane in MDCK cells, but was localized to the
apical membrane in LLC-PK1 cells. Similarly, HA-Y543, a construct in which a
tyrosine-based motif was introduced into the cytoplasmic tail of influenza
hemagglutinin, was sorted to the basolateral membrane of MDCK cells and retained
at the apical membrane of LLC-PK1 cells. A chimera in which the cytoplasmic tail
of the H,K-ATPase beta subunit protein was replaced with the analogous region of
the Na,K-ATPase beta subunit polypeptide was localized to both surface domains of
MDCK cells. Mutation of tyrosine-20 of the H,K-ATPase beta subunit cytoplasmic
sequence to an alanine was sufficient to disrupt basolateral localization of this
polypeptide. In contrast, these constructs all remain localized to the apical
membrane in LLC-PK1 cells. The FcRII-B2 protein bears a di-leucine motif and is
found at the basolateral membrane of both MDCK and LLC-PK1 cells. These results
demonstrate that polarized epithelia are able to discriminate between different
classes of specifically defined membrane protein sorting signals.
PMID- 9756933
TI - An essential role for autophosphorylation in the dissociation of activated
protein kinase C from the plasma membrane.
AB - The cellular localization of protein kinase C (PKC) is intimately associated with
the regulation of its biological activity. Previously we have demonstrated that
the redistribution of PKC to the plasma membrane in response to physiological
stimuli is followed by a rapid returning of PKC back to the cytoplasm (Feng, X.,
Zhang, J., Barak, L. S., Meyer, T., Caron, M. G., and Hannun, Y. A. (1998) J.
Biol. Chem. 273, 10755-10762). Although the process of PKC membrane targeting has
been extensively studied, the molecular mechanism underlying the dissociation of
membrane-bound PKC remains unclear. In the present study, by examining the
dynamic distribution of wild-type PKC betaII and its kinase-deficient mutant
(K371R), we demonstrate that kinase activity is required for PKC membrane
dissociation. Moreover, the inability of PKC betaII(K371R) to dissociate from the
plasma membrane in cells overexpressing wild-type PKC betaII suggests that
autophosphorylation activity of the kinase might be essential for its membrane
dissociation. This was further supported by mutational analysis of two in vivo
autophosphorylation sites on PKC betaII. The replacement of Ser660 or Thr641 by
alanine (S660A or T641A) was found to synergistically reduce the reversal of PKC
betaII membrane translocation, whereas the replacement of the same amino acids by
glutamic acid (S660E or T641E), an amino acid commonly used to mimic phosphate,
results in mutants behaving similar to wild-type PKC betaII. These findings point
to an essential role for autophosphorylation in the dissociation of activated PKC
from the plasma membrane and suggest that, like PKC membrane translocation, the
returning of PKC to the cytoplasm after its activation is also delicately
regulated.
PMID- 9756934
TI - Transcriptional factor mutations reveal regulatory complexities of heat shock and
newly identified stress genes in Saccharomyces cerevisiae.
AB - A computer-aided pattern search of the entire yeast genome was designed and used
to identify 186 putative stress response element-regulated genes in Saccharomyces
cerevisiae. Transcript levels of eight of these candidate genes were examined,
and three (37%) were shown to be heat shock- and DNA damage-inducible and to
require the Msn2p and Msn4p transcriptional activators for stress regulation.
Significantly, several heat shock protein (HSP) genes were identified in this
computer search. Using a series of single and multiple regulatory mutants, we
demonstrate unexpected regulatory complexities among the HSP genes from S.
cerevisiae following heat shock.
PMID- 9756935
TI - Dna2 of Saccharomyces cerevisiae possesses a single-stranded DNA-specific
endonuclease activity that is able to act on double-stranded DNA in the presence
of ATP.
AB - To gain further insights into the biological functions of Dna2, previously known
as a cellular replicative helicase in Saccharomyces cerevisiae, we examined
biochemical properties of the recombinant Dna2 protein purified to homogeneity.
Besides the single-stranded (ss) DNA-dependent ATPase activity as reported
previously, we were able to demonstrate that ssDNA-specific endonuclease activity
is intrinsically associated with Dna2. Moreover, Dna2 was capable of degrading
duplex DNA in an ATP-dependent fashion. ATP and dATP, the only nucleotides
hydrolyzed by Dna2, served to stimulate Dna2 to utilize duplex DNA, indicating
their hydrolysis is required. Dna2 was able to unwind short duplex only under the
condition where the endonuclease activity was minimized. This finding implies
that Dna2 unwinds only partially the 3'-end of duplex DNA and generates a stretch
of ssDNA of limited length, which is subsequently cleaved by the ssDNA-specific
endonuclease activity. A point mutation at the conserved ATP-binding site of Dna2
inactivated concurrently ssDNA-dependent ATPase, ATP-dependent nuclease, and
helicase activities, indicating that they all reside in Dna2 itself. By virtue of
its nucleolytic activities, the Dna2 protein may function in the maintenance of
chromosomal integrity, such as repair or other related process, rather than in
propagation of cellular replication forks.
PMID- 9756936
TI - Biological activity and modular structure of RE-1-silencing transcription factor
(REST), a repressor of neuronal genes.
AB - The zinc finger protein RE-1-silencing transcription factor (REST)1 is a
transcriptional repressor that represses neuronal genes in nonneuronal tissues.
Transfection experiments of neuroblastoma cells using a REST expression vector
revealed that synapsin I promoter activity is controlled by REST. The biological
activity of REST was further investigated using a battery of model promoters
containing strong promoters/enhancers and REST binding sites. REST functioned as
a transcriptional repressor when REST binding motifs derived from the genes
encoding synapsin I, SCG10, alpha1-glycine receptor, the beta2-subunit of the
neuronal nicotinic acetylcholine receptor, and the m4-subunit of the muscarinic
acetylcholine receptor were present in the promoter region. No differences in the
biological activity of these REST binding motifs tested were detected. Moreover,
we found that REST functioned very effectively as a transcriptional repressor at
a distance. Thus, REST represents a general transcriptional repressor that blocks
transcription regardless of the location or orientation of its binding site
relative to the enhancer and promoter. This biological activity could also be
attributed to isolated domains of REST. Both repressor domains identified at the
N and C termini of REST were transferable to a heterologous DNA binding domain
and functioned from proximal and distal positions, similar to the REST protein.
PMID- 9756937
TI - Requirement of caspase-3(-like) protease-mediated hydrogen peroxide production
for apoptosis induced by various anticancer drugs.
AB - Caspase-3(-like) proteases play important roles in controlling mammalian
apoptosis. However, the downstream events from the caspase-3(-like) protease
activation to death of cells are still unclear. Previously, we reported that
hydrogen peroxide (H2O2) was generated by the activation of caspase-3(-like)
proteases in the process of tyrosine kinase inhibitor-induced apoptosis in human
small cell lung carcinoma Ms-1 cells. In the present study, we examined whether
generation of H2O2 is a critical event for the apoptotic pathway downstream of
caspase-3(-like) protease activation by various anticancer drugs. Anticancer
drugs such as camptothecin, vinblastine, inostamycin, and adriamycin induced
activation of caspase-3(-like) proteases and apoptosis. Generation of H2O2 was
commonly detected after treatment with each of the four anticancer drugs, and
scavenging of H2O2 caused cells to fail to undergo apoptosis. Moreover,
anticancer drug-induced H2O2 production was inhibited not only by an inhibitor of
caspase-3(-like) proteases but also by diphenyleneiodonium chloride, an inhibitor
of flavonoid-containing enzymes such as NADPH oxidase. However, activation of
caspase-3(-like) proteases was not inhibited by diphenyleneiodonium chloride.
These findings suggest that activation of caspase-3(-like) proteases by various
anticancer drugs causes generation of H2O2 presumably through the activation of
NADPH oxidase, thereby inducing apoptosis. Therefore, H2O2 may function as a
common mediator for apoptosis induced by various anticancer drugs.
PMID- 9756938
TI - The COOH-terminal tyrosine phosphorylation sites on IRS-1 bind SHP-2 and
negatively regulate insulin signaling.
AB - Activation of tyrosine kinases by numerous growth factor and cytokine receptors
leads to tyrosine phosphorylation of the insulin receptor substrate (IRS)
proteins. Tyrosine-phosphorylated motifs on the IRS proteins bind to the SH2
domains in proteins that mediate downstream signals, including
phosphatidylinositol 3'-kinase, GRB-2, and SHP-2. We investigated the function of
the two SHP-2 binding COOH-terminal tyrosines of IRS-1 by replacing them with
phenylalanine (IRS-1(FCT)). IRS-1(FCT) failed to bind SHP-2 or mediate its
tyrosine phosphorylation during insulin stimulation. Although several reports
suggest a critical role for SHP-2 in insulin stimulated mitogen-activated protein
kinase activation and cell proliferation, IRS-1(FCT) mediated these effects
normally in 32D cells. Indeed, IRS-1(FCT) exhibited increased tyrosine
phosphorylation, phosphatidylinositol 3'-kinase binding and activation of protein
synthesis in response to insulin. These results suggest that SHP-2 attentuates
the phosphorylation and downstream signal transmission of IRS-1 and that the
interaction of IRS-1 and SHP-2 is an important regulatory event which attenuates
insulin metabolic responses.
PMID- 9756939
TI - Overexpressed activated retinoid X receptors can mediate growth inhibitory
effects of retinoids in human carcinoma cells.
AB - Retinoic acid receptors (RARs) and retinoid X receptors (RXRs) mediate the
effects of retinoids on gene expression by binding to response elements in
retinoid-sensitive genes. RAR- but not RXR-selective retinoids were found in many
previous studies to suppress the growth of various cells, implicating RXR-RAR in
these effects. Using a co-expression vector for identifying cells that expressed
retinoid receptors transiently and 5'-bromo-2'-deoxyuridine incorporation for
labeling DNA-synthesizing cells, we found that RXR-selective retinoids inhibited
DNA synthesis in squamous carcinoma 1483 cells transfected with RXRalpha but not
with RARs. Ligand-induced transcription of the reporter luciferase gene via the
activation of RXR-RXR but not RXR-RAR correlated with growth suppression. Studies
with RXRalpha deletion mutants indicated that the DNA binding and the ligand
binding domains are essential for mediating growth inhibition. A point mutation
in the ligand binding domain (L430F) that decreased RXRalpha homodimerization
compromised its growth inhibitory function. Further, RXRalpha mutant (F313A),
which functions as a constitutively active receptor, inhibited DNA synthesis in
the absence of ligand. These results demonstrate that RXR homodimer activation
leads to growth inhibition and suggest that transfection of RXRalpha and
treatment with RXR-selective retinoids or the transfection of constitutively
activated RXRalpha mutant alone may have a therapeutic potential.
PMID- 9756940
TI - The early growth response protein (EGR-1) regulates interleukin-2 transcription
by synergistic interaction with the nuclear factor of activated T cells.
AB - The early growth response-1 gene (EGR-1) is induced by a wide range of stimuli in
diverse cell types; however, EGR-1-regulated genes display a highly restricted
pattern of expression. Recently, an overlapping Sp1.EGR-1 binding site has been
identified within the interleukin-2 (IL-2) gene promoter directly upstream of the
binding site for the nuclear factor of activated T cells (NFAT). We used
transfection assays to study how the abundantly and constitutively expressed Sp1
protein and the immediate early EGR-1 zinc finger protein regulate IL-2 gene
expression. Here, we identify EGR-1 as an important activator of the IL-2 gene.
In Jurkat T cells, EGR-1 but not Sp1 acts as a potent coactivator for IL-2
transcription, and in combination with NFATc, EGR-1 increases transcription of an
IL-2 reporter construct 200-fold. Electrophoretic mobility shift assays reveal
that recombinant EGR-1 and NFATc bind independently to their target sites within
the IL-2 promoter, and the presence of both sites on the same DNA molecule is
required for EGR-1.NFATc.DNA complex formation. The transcriptional synergy
observed here for EGR-1 and NFATc explains how the abundant nuclear factor EGR-1
contributes to the expression of restrictively expressed genes.
PMID- 9756941
TI - Molecular role for the Rab binding platform of guanine nucleotide dissociation
inhibitor in endoplasmic reticulum to Golgi transport.
AB - Guanine nucleotide dissociation inhibitor (GDI) regulates the recycling of Rab
GTPases involved in vesicle targeting and fusion. We have analyzed the
requirement for conserved amino acid residues in the binding of Rab1A and the
function of GDI in transport of cargo between the endoplasmic reticulum (ER) and
the Golgi apparatus. Using a new approach to monitor GDI-Rab interactions based
on the change in fluorescence associated with the release of methylanthraniloyl
guanosine di(tri)phosphate-GDP (mGDP) from Rab, we show that residues previously
implicated in the binding of the synapse-specific Rab3A, including Gln-236, Arg
240, and Thr-248, are essential for the binding of Rab1A. Mutation of each of
these residues has potent effects on the ability of GDI to remove Rab1A from
membranes and inhibit ER to Golgi transport in vitro. Given the sequence
divergence between Rab1A and 3A (35% identity), these residues are proposed to
play a general role in GDI function in the cell. In contrast, several other
residues found within or flanking the Rab-binding region were found to have
differential effects in the recognition and recycling of Rab1A and 3A, and
therefore direct selective interaction of GDI with individual Rab proteins.
Intriguingly, mutation of one residue, Arg-70, led to a reduction of Rab1A
binding, failed to extract Rab1A from membranes in vitro, yet bound membranes
tightly and potently inhibited ER to Golgi transport. These results provide
evidence that novel membrane-associated factor(s) mediate Rab-independent GDI
interaction with membranes.
PMID- 9756942
TI - Regulation of nucleoside transport by lipopolysaccharide, phorbol esters, and
tumor necrosis factor-alpha in human B-lymphocytes.
AB - Nucleoside transport systems and their regulation in human B-lymphocytes have
been characterized using the cell lines Raji and Bare lymphoma syndrome-1 (BLS-1)
as experimental models. These cells express at least three different nucleoside
transport systems as follows: a nitrobenzylthioinosine-sensitive equilibrative
transport system of the es-type, which appears to be associated with hENT1
expression, and two Na+-dependent transport systems that may correspond to N1 and
to the recently characterized N5-type, which is nitrobenzylthioinosine-sensitive
and guanosine-preferring. B cell activators such as phorbol 12-myristate 13
acetate and lipopolysaccharide (LPS) up-regulate both concentrative transport
systems but down-regulate the equilibrative es-type transporter, which correlates
with lower hENT1 mRNA levels. These effects are dependent on protein kinase C
activity. Phorbol 12-myristate 13-acetate and LPS also induce an increase in
tumor necrosis factor-alpha (TNF-alpha) mRNA levels, which suggest that this
cytokine may mediate some of the effects triggered by these agents, since
addition of TNF-alpha alone can increase N1 and N5 transport activities by a
mechanism that also depends on protein kinase C activation. Interestingly, TNF
alpha down-regulates es activity, but this effect cannot be abolished by
inhibiting protein kinase C. This study reveals differential regulation of
nucleoside transport systems following activation of human B-lymphocyte cell
lines by agents of physiological relevance such as TNF-alpha and LPS. Moreover,
it indicates that the recently characterized N5 transport system can also be
regulated following B cell activation, which may be relevant to lymphocyte
physiology and to the treatment of lymphocyte malignancies.
PMID- 9756943
TI - Amino acid sequence requirement for efficient incorporation of
glycosylphosphatidylinositol-associated proteins into the cell wall of
Saccharomyces cerevisiae.
AB - During cell wall biogenesis in Saccharomyces cerevisiae, some
glycosylphosphatidylinositol (GPI)-attached proteins are detached from GPI
moieties and bound to beta-1,6-glucan of the cell wall. The amino acid sequence
requirement for the incorporation of GPI-attached proteins into the cell wall was
studied by using reporter fusion proteins. Only the short omega-minus region
composed of five amino acids, which is located upstream of the omega site for GPI
attachment, determined the cellular localization of the GPI-associated proteins.
Within the omega-minus region, amino acid residues at the omega-4 or -5 and omega
2 sites were important for the cell wall incorporation. Yap3p, a well
characterized GPI-anchored plasma membrane aspartic protease, was localized in
the cell wall when the omega-minus region was mutated to sequences containing Val
or Ile at the omega-4 or -5 site and Val or Tyr at the omega-2 site.
PMID- 9756944
TI - Differential signaling by the epidermal growth factor-like growth factors
neuregulin-1 and neuregulin-2.
AB - The neuregulins comprise a subfamily of epidermal growth factor (EGF)-like growth
factors that elicit diverse cellular responses by activating members of the ErbB
family of receptor tyrosine kinases. Although neuregulin-1 and neuregulin-2 are
both binding ligands for the ErbB3 and ErbB4 receptors, they exhibit distinct
biological activities depending on cellular context. In MDA-MB-468 human mammary
tumor cells, neuregulin-2beta (NRG2beta) inhibits cell growth, whereas neuregulin
1beta (NRG1beta) does not. In these cells, NRG2beta appears to preferentially act
through the EGF receptor, stimulating receptor tyrosine phosphorylation and the
recruitment of phospholipase C-gamma, Cbl, SHP2, and Shc to that receptor.
NRG1beta preferentially acts through ErbB3 in these cells by stimulating the
tyrosine phosphorylation and recruitment of phosphatidylinositol 3-kinase and Shc
to that receptor. In MDA-MB-453 cells, both NRG1beta and NRG2beta stimulate the
tyrosine phosphorylation of the ErbB2 and ErbB3 receptors to similar extents, but
only NRG1beta potently stimulates morphological changes consistent with their
differentiation. The profiles of SH2 domain-containing proteins that are
efficiently recruited to activated receptors differ for the two factors. These
observations indicate that despite their overlapping receptor specificity, the
neuregulins exhibit distinct biological and biochemical properties. Since both of
these cell lines express only two of the known ErbB receptors, our results imply
that EGF-like ligands might elicit differential signaling within the context of a
single receptor heterodimer.
PMID- 9756945
TI - Caveolin is an activator of insulin receptor signaling.
AB - Recent data have demonstrated that caveolin, a major structural protein of
caveolae, negatively regulates signaling molecules localized to caveolae. The
interaction of caveolin with several caveolae-associated signaling proteins is
mediated by the binding of the scaffolding region of caveolin to a hydrophobic
amino acid-containing region within the regulated proteins. The presence of a
similar motif within the insulin receptor kinase prompted us to investigate the
caveolar localization and regulation of the insulin receptor by caveolin. We
found that overexpression of caveolin-3 augmented insulin-stimulated
phosphorylation of insulin receptor substrate-1 in 293T cells but not the
phosphorylation of insulin receptor. Peptides corresponding to the scaffolding
domain of caveolin potently stimulated insulin receptor kinase activity toward
insulin receptor substrate-1 or a Src-derived peptide in vitro and in a caveolin
subtype-dependent fashion. Peptides from caveolin-2 exhibited no effect, whereas
caveolin-1 and -3 stimulated activity 10- and 17-fold, respectively. Peptides
which increased insulin receptor kinase activity did so without affecting insulin
receptor auto-phosphorylation. Furthermore, the insulin receptor bound to
immobilized caveolin peptides, and this binding was inhibited in the presence of
free caveolin-3 peptides. Thus, we have identified a novel mechanism by which the
insulin receptor is bound and activated by specific caveolin subtypes.
Furthermore, these data define a new role for caveolin as an activator of
signaling.
PMID- 9756946
TI - Down-regulation of cytochrome P450 1A1 gene promoter by oxidative stress.
Critical contribution of nuclear factor 1.
AB - Oxidative stress interferes with several cellular functions, in particular
transcriptional regulation. We show here that the human cytochrome P450 1A1
(CYP1A1) is down-regulated at the transcriptional level by oxidative stress.
Basal as well as 2,3,7, 8-tetrachloro-p-dioxin-induced promoter activities are
strongly impaired by H2O2 treatment or glutathione depletion with L-buthionine
(S,R)-sulfoximine. Tumor necrosis factor alpha inhibits CYP1A1 expression, and
this inhibition is prevented by the antioxidant pyrrolidine dithiocarbamate. We
show that these regulations depend on the integrity of the nuclear factor 1 (NFI)
site located in the proximal promoter. We therefore examined the redox regulation
of this transcription factor. Treatment of human HepG2 or rat H4 hepatoma cells
with H2O2 or L-buthionine-(S, R)-sulfoximine inactivates the binding of the NFI
transcription factor to its DNA consensus sequence. Furthermore, H2O2 treatment
leads to a dose-dependent decrease of reporter gene expressions driven by
promoters containing NFI binding sites. Glutathione depletion and catalase
inhibition also repress a NFI-driven promoter. Under the same conditions, the CP
1 transcription factor activity is not affected by oxidative stress. Thus, NFI
seems particularly sensitive to oxidative stress. This accounts, at least
partially, for the regulation of cyp1A1 gene expression.
PMID- 9756947
TI - Molecular cloning and characterization of RGC-32, a novel gene induced by
complement activation in oligodendrocytes.
AB - Sublytic complement activation on oligodendrocytes (OLG) down-regulates
expression of myelin genes and induces cell cycle in culture. Differential
display (DD) was used to search for new genes whose expression is altered in
response to complement and that may be involved in cell cycle activation. DD
bands showing either increased or decreased mRNA expression in response to
complement were identified and designated Response Genes to Complement (RGC) 1
32. RGC-1 is identical with heat shock protein 105, RGC-2 with poly(ADP-ribose)
polymerase, and RGC-10 with IP-10. A new gene, RGC-32, that encodes a protein of
137 amino acids was cloned. RGC-32 has no homology with other known proteins, and
contains no motif that would indicate its function. In OLG, the mRNA expression
was increased by complement activation and by terminal complement complex
assembly. RGC-32 protein was localized in the cytoplasm and co-immunoprecipitated
with cdc2 kinase. Overexpression of RGC-32 increased DNA synthesis in OLGxC6
glioma cell hybrids. These results suggest that RGC-32 may play a role in cell
cycle activation.
PMID- 9756948
TI - Novel alternative splice variants of cGMP-binding cGMP-specific
phosphodiesterase.
AB - After our recent findings that the amino-terminal portion of rat cGMP-binding,
cGMP-specific phosphodiesterase (cGB-PDE) differs from those of bovine and human
cGB-PDEs, we found two forms of canine cGB-PDE cDNAs (CFPDE5A1 and CFPDE5A2) in
canine lung. Each contained a distinct amino-terminal sequence, CFPDE5A1,
possessing an amino-terminal portion with sequence similar to those of bovine and
human, and CFPDE5A2, having one similar to that of rat. Other portions coding for
the cGMP binding domains and the catalytic domain were conserved. Both CFPDE5A1
and CFPDE5A2 transcripts were detected in the cerebellum, hippocampus, retina,
lung, heart, spleen, and thoracic artery. CFPDE5A1 transcripts were particularly
abundant in the pylorus, whereas CFPDE5A2 transcripts were quite low in this
tissue. CFPDE5A1 and CFPDE5A2 expressed in COS-7 cells had cGMP Km values of 2.68
and 1.97 microM, respectively, and both were inhibited by a low concentration of
a cGB-PDE inhibitor, Zaprinast. Both CFPDE5A1 and CFPDE5A2 bound cGMP to their
allosteric cGMP binding domains, and this cGMP binding was stimulated by 3
isobutyl-1-methylxanthine. Thus, two types of alternative splice variants of
canine cGB-PDE have been identified and shown to have similar biological
properties in vitro.
PMID- 9756949
TI - Regulation of actin binding and actin bundling activities of fascin by caldesmon
coupled with tropomyosin.
AB - Human fascin is an actin-bundling protein and is thought to play a role in the
formation of microfilament bundles of microspikes and stress fibers in cultured
cells. To explore the regulation of fascin-actin interaction, we have examined
the effects of culture cell caldesmon and tropomyosin (TM) on actin binding
activity of human fascin. Caldesmon alone or TM alone has little or no effect on
the actin binding of fascin. However, caldesmon together with TM completely
inhibits actin binding of human fascin. When calmodulin is added, the inhibition
of fascin-actin interaction by caldesmon and TM becomes Ca2+ dependent because
Ca2+/calmodulin blocks actin binding of caldesmon. Furthermore, as
phosphorylation of caldesmon by cdc2 kinase inhibits actin binding of caldesmon,
phosphorylation can also control actin binding of fascin in the presence of TM.
As expected by the inhibition of fascin-actin binding, caldesmon coupled with TM
also inhibits actin bundling activity of fascin. Whereas smooth muscle caldesmon
alone or TM alone shows no effect, caldesmon together with TM completely inhibits
actin bundling activity of fascin. This inhibition is again Ca2+ dependent when
calmodulin is added to the system. These results suggest important roles for
caldesmon and TM in the regulation of the function of human fascin.
PMID- 9756950
TI - Transcriptional properties of RNA polymerase II within triplet repeat-containing
DNA from the human myotonic dystrophy and fragile X loci.
AB - Expansion of a (CTG)n segment within the 3'-untranslated region of the myotonic
dystrophy protein kinase gene alters mRNA production. The inherent ability of RNA
polymerase II to transcribe (CTG)17-255 tracts corresponding to DNA from normal,
unstable, and affected individuals, and the normal (CGG)54 fragile X repeat
tract, was analyzed using a synchronized in vitro transcription system. Core RNA
polymerase II transcribed all repeat units irrespective of repeat length or
orientation. However, approximately 50% of polymerases transiently halted
transcription (with a half-life of approximately 10 +/- 1 s) within the first and
second CTG repeat unit and a more transient barrier to elongation was observed
roughly centered within repeats 6-9. Transcription within the remainder of the
CTG tracts and within the CCG, CGG, and CAG tracts appeared uniform with average
transcription rates of 170, 250, 300, and 410 nucleotides/min, respectively.
These differences correlated with changes in the sequence-specific transient
pausing pattern within the CNG repeat tracts; individual incorporation rates were
slower after incorporation of pyrimidine residues. Unexpectedly, approximately 4%
of the run-off transcripts were, depending on the repeat sequence, either 15 or
18 nucleotides longer than expected. However, these products were not produced by
transcriptional slippage within the repeat tract.
PMID- 9756951
TI - Template end-to-end transposition by RNA polymerase II.
AB - On 5'-template strand protruding templates, promoter-initiated run-off
transcription by RNA polymerase II generates discrete, 15-16-nucleotide (nt)
longer than expected products whose production is abrogated by elongation factor
SII (Parsons, M. A., Sinden, R. R., and Izban, M. G. (1998) J. Biol. Chem. 273,
26998-27008). We demonstrate that template terminal complexes produce these RNAs
and that transcript extension is a general and salt-sensitive (250 mM) feature of
run-off transcription. On 5'-overhung templates the extended run-off transcripts
appear to be retained within an RNA-DNA-enzyme ternary complex, and SII
facilitates resumption of transcript elongation via a dinucleotide truncation
intermediate. Moreover, on one of the 5-overhung templates, the initially
extended complexes spontaneously resumed transcript extension and were uniquely
resistant to salt (250 mM) challenge. However, SII did not facilitate this long
distance extension on all template ends. Run-off transcripts on a blunt-ended
template were initially extended by 2-11 nt (roughly in 2-nt increments); SII
addition either before or after extension resulted in the accumulation of a 4-5
nt extension product. Based on these findings, we propose that the initial and
continuously extended RNAs reflect intermediates and successful completion of
template end-to-end transposition (template switching) by RNA polymerase II,
respectively. Both the template end sequence and structure influenced the success
of such an event.
PMID- 9756952
TI - Structural requirements for in vivo myosin I function in Aspergillus nidulans.
AB - We have investigated the minimal requirements of the tail region for myosin I
function in vivo using the filamentous fungus Aspergillus nidulans. The CL3
strain (McGoldrick, C. A., Gruver, C., and May, G. S. (1995) J. Cell Biol. 128,
577-587) was transformed with a variety of myoA constructs containing mutations
in the IQ, TH-1-like, SH3, and proline-rich domains by frameshift or in-frame
deletions of the tail domains. The resulting strains contained wild type myoA
driven by the alcA promoter and a mutant myoA driven by its endogenous promoter.
This strategy allowed for selective expression of the wild type and/or mutant
form of MYOA by the choice of growth medium. Proper septation and hyphal
branching were found to be dependent on the interaction of the IQ motifs with
calmodulin, as well as, the presence of its proline-rich domain. Additionally, a
single proline-rich motif was sufficient for nearly wild type MYOA function. Most
surprisingly, the SH3 domain was not essential for MYOA function. These studies
expand our previous knowledge of the function of MYOA to include roles in hyphal
morphogenesis, septal wall formation, and cell polarity, laying the groundwork
for more detailed investigations on the function of the various tail domains in
MYOA.
PMID- 9756953
TI - The gene encoding the myeloid-related protein 14 (MRP14), a calcium-binding
protein expressed in granulocytes and monocytes, contains a potent enhancer
element in the first intron.
AB - Myeloid-related proteins 8 and 14 (MRP8 and MRP14) are two Ca2+-binding proteins
of the S-100 family highly abundant in myelomonocytic cells. The expression is
not only dependent on the developmental status of the cell but also on the
inflammatory situation in the tissue. In order to identify regulatory elements
responsible for the high expression of MRP14 in myeloid cells, reporter gene
constructs have been transfected into HL-60 cells, Mono Mac 6 cells, and L132
cells. We demonstrated that a DNA element in the first intron (positions 153-361)
enhances the transcriptional activity of the homologous promoter and of the
heterologous herpes simplex virus thymidine kinase promoter up to 37-fold. To
further identify the functional site, the region between positions 153 and 192
was analyzed functionally using the thymidine kinase promoter. The region
increased the expression in the same magnitude as the complete intron. This
enhancer is highly conserved in the human and murine MRP genes, indicative of its
involvement in the transcription of MRPs. Protein binding to the region is
demonstrated using EMSA, DNA cross-linking, Southwestern blotting, and affinity
purification. Affinity purification confirms that four proteins bind to the
enhancer element.
PMID- 9756954
TI - Quantitative in situ localization of tenascin-C alternatively spliced transcripts
in the avian optic tectum.
AB - PURPOSE: Tenascin-C is an extracellular matrix glycoprotein found at sites of
embryonic cell motility, including the developing visual system. Numerous
alternatively spliced variants of tenascin-C have been identified, and these
variants have distinctive properties in vitro. The purpose of this study was to
use quantitative in situ hybridization to determine the relative abundance of
transcripts encoding the alternatively spliced fibronectin type III repeats of
tenascin-C in the embryonic avian optic tectum. METHODS: Similarly sized DNA
probes specific for sequences encoding the alternatively spliced repeats of
tenascin-C were labeled with 35-S and applied to frozen sections of the E10 optic
tectum. After determining the linear period of exposure, silver grain densities
in the ventricular zone were calculated. RESULTS: Densitometric analysis revealed
that more than half of the total tenascin-C mRNAs expressed in the ventricular
zone of the E10 optic tectum encode the variable fibronectin type III repeats
"A," "AD1" and "D." Transcripts encoding other variable repeats were detectable,
but at considerably lower levels. CONCLUSIONS: The most abundant form of tenascin
C in the developing optic tectum has a molecular weight of 230 kDa. Most of this
form contains the variable repeats "A," "AD1," and "D," a combination of
fibronectin type III repeats that has previously been identified only in a tumor
derived cell line.
PMID- 9756955
TI - Structural features of the aldose reductase and aldehyde reductase inhibitor
binding sites.
AB - The three-dimensional structures of aldose reductase and aldehyde reductase,
members of the aldo-keto reductase superfamily, are composed of similar
alpha/beta TIM-barrels. However, examination of the structures reveals that the
inhibitor-binding site of aldose reductase differs from that of aldehyde
reductase due to the participation of non-conserved residues in its formation.
This information will be useful in the design of inhibitors to prevent or delay
diabetic retinopathy. A review of the structures of the inhibitor-binding sites
is presented.
PMID- 9756956
TI - Biomechanical testing sequelae relevant to spinal fusion and instrumentation.
AB - The increasing prevalence of spinal disorders and associated treatments has
produced a dramatic increase in the number of available devices. The
biomechanical evaluation leading to the design, development, and implementation
of spinal instrumentation has resulted in a number of in vitro and in vivo
testing methods. This article reviews some of the methods and associated results
obtained by various evaluation techniques of spinal fusion hardware. Current work
and future considerations also are presented.
PMID- 9756957
TI - The use of diagnostic imaging to assess spinal arthrodesis.
AB - Despite advances in surgical techniques and internal fixation devices,
pseudarthrosis remains a significant factor in the clinical failure of attempted
fusions in the cervical, thoracic, and lumbar spine. This article reviews the use
of diagnostic imaging in the assessment of spinal fusion, with a focus on the
accuracy of different imaging modalities based on surgical exploration. A cost
effective strategy for the radiographic follow-up of patients after spinal fusion
surgery also is presented.
PMID- 9756958
TI - The biology of posterolateral lumbar spinal fusion.
AB - This article reviews the existing knowledge base concerning the biology of spinal
fusion, with the understanding that the focus is weighted toward posterolateral
lumbar spinal fusion because of a relative paucity of biologic information on
healing of other types of fusions. The discussion focuses first on the basic
science of spinal fusion healing from the standpoint of animal modeling. Next,
the discussion centers on the multitude of local factors that can affect fusion
healing. Finally, the numerous systemic factors known to affect fusion healing
are discussed.
PMID- 9756959
TI - Biologic enhancement of spinal fusion.
AB - Scientific advances in the past decade have generated considerable clinical
interest in developing biologic tools that may ultimately enhance spinal fusion.
This article reviews the current understanding of each of these and other fusion
enhancing tools with particular attention to the results of in vivo animal
experimentation and, where available, objective clinical data.
PMID- 9756960
TI - Laparoscopic spinal fusion.
AB - This article details the development of the laparoscopic technique of interbody
spinal fusion. The rationale for this procedure is discussed as are indications,
contraindications, and operative technique. The results of over 100 laparoscopic
lumbar fusions are presented along with their complications and surgical
recommendations.
PMID- 9756961
TI - Percutaneous interbody fusions.
AB - Percutaneous interbody fusion procedures have evolved as a result of the need for
precise and specific access corridors to facilitate the application of technology
to perform these procedures. Endoscopic visualization has expanded minimally
invasive capabilities, particularly in the thoracic and lumbar spine. Refinement
of grafting concepts and structural composition continues. Based on the
historical evolution of the described percutaneous interbody fusion procedures,
the future of minimally invasive interbody arthrodesis shows promise through the
ongoing definition of access corridors and the refinement of operative tools and
techniques.
PMID- 9756962
TI - Laparoscopic bone dowel fusions of the lumbar spine.
AB - Studies that show laparoscopic lumbar fusion to decrease cost or time of
hospitalization or to increase the speed or incidence of return to activities are
not currently available. Laparoscopic fusion of the lumbar spine appears to be a
potentially attractive approach to treating axial back pain secondary to
different causes. Although the technique is attractive because of its minimally
invasive nature and marketing allure, it has yet to be established as to what the
true clinical efficacy of this procedure will be. Further clinical study of these
techniques with longer follow-up, and case-controlled studies should help
clinicians to know the best fusion technique to offer patients.
PMID- 9756964
TI - Complications of spinal fusion in adult patients more than 60 years of age.
AB - This article describes the overall rate, characteristics, and predictive factors
for major and minor complications in spinal fusion patients over 60 years of age
(or greater) cared for in the authors' institution. Special emphasis is placed on
establishing the most valid incidence of complications after spinal fusion by
extracting the information directly from the pateint's permanent medical or
clinical database record. Once the spinal surgery risk profile for the elderly
patient is established, treatment interventions to modify these risks can be
implemented and evaluated prospectively and longitudinally to maximize spinal
surgery outcomes.
PMID- 9756963
TI - Minimally invasive posterolateral lumbar arthrodesis.
AB - Video-assisted and optical techniques have been adapted to minimally invasive
approaches for lumbar arthrodesis. They hold the promise of improved outcomes and
reduced morbidity, but development is recent and validation is limited.
PMID- 9756965
TI - Complications in spinal fusion.
AB - Complications in spinal fusion can lead to less than desirable results. The
complications of spinal fusion in the cervical and lumbar spine are discussed.
Methods of avoiding and correcting complications also are reviewed. Through a
better understanding, it is hoped that complications can be prevented.
PMID- 9756966
TI - Alternatives to spinal fusion.
AB - Techniques have changed significantly with the advent of less invasive surgical
techniques for disc excision and spinal fusion; these include the development of
rigid internal fixation devices using multiple points of fixation and the better
knowledge of the biology of spinal fusion. Despite these improvements in
technology, room exists for alternative forms of surgical treatment because of
significant failures particularly related to spinal fusions.
PMID- 9756967
TI - Outcome assessment after spinal fusion: why and how?
AB - Outcomes of medical interventions today must reflect a more complete array of
measurements, including health status, patient satisfaction, medical costs, and
quality of life. This article discusses the rationale and methodology involved
with measurement of health status, particularly as it applies to spinal disorders
and spinal fusion. Generic and disease-specific instruments are reviewed, and
their limitations are also discussed.
PMID- 9756968
TI - Indications and trends in use in cervical spinal fusions.
AB - Anterior cervical decompression and arthrodesis has evolved over the last 40
years and has become the preferred procedure for managing many cervical spine
disorders. The first half of this article discusses the indications for cervical
fusion in the management of traumatic, degenerative, neoplastic, infectious, and
congenital conditions of the cervical spine. The second half of this article
discusses the recent trends in use of cervical spine fusions that demonstrate the
increasing frequency of this procedure in the United States over the last 10
years.
PMID- 9756969
TI - Cervical trauma: rationale for selecting the appropriate fusion technique.
AB - The selection of the appropriate surgical approach in the management of an
unstable cervical spine injury is predicated on the biomechanic deficiencies of
the bony and ligamentous structures, the age of the patient, the level of
experience of the surgeon, and the concomitant medical comorbidities. The optimal
approach ideally is the least invasive, provides the greatest benefit-to-risk
ratio in terms of potential injury to contiguous neurovascular structures, and
provides adequate stabilization to avoid cumbersome external immobilization and
allows early rehabilitation. This article discusses anterior, posterior, and
combined stabilization techniques in patients who have sustained trauma to the
upper and lower cervical spine.
PMID- 9756970
TI - Cervical degenerative disease: rationale for selecting the appropriate fusion
technique (Anterior, posterior, and 360 degree).
AB - Many options exist for those treating cervical disc herniation, spondylosis, and
deformity. This article examines the options for cervical degenerative fusions,
the appropriate choice of technique (anterior, posterior, or combined
anterior/posterior techniques), as well as bone graft and instrumentation
choices.
PMID- 9756972
TI - Clinical outcomes after cervical spine fusion.
AB - The advent of sterile technique, modern anesthesia, and organized industrial
society have allowed for great advances and widespread use of cervical
arthrodesis for a variety of disorders. This article defines expected outcome for
cervical arthrodesis used to treat degenerative disease, trauma, deformity, and a
variety of other disorders.
PMID- 9756971
TI - Cervical deformity: rationale for selecting the appropriate fusion technique
(anterior, posterior, and 360 degree).
AB - This article examines cervical deformities and their treatments, such as
iatrogenic deformities, posttraumatic deformities, ankylosing spondylitis,
rheumatoid arthritis, degenerative subaxial spondylolisthesis, myopathy,
infectious spondylitis, and tumors. Congenital scoliosis and kyphosis and
torticollis and rotatory atlanto-axial subluxation also are discussed.
PMID- 9756973
TI - Indications for thoracic and lumbar spine fusion and trends in use.
AB - Over the last 10 years, the annual number of spinal procedures performed in the
United States has more than doubled. In 1996, there were roughly 29,000 thoracic
or dorsal fusion procedures, which made up almost 13% of all spine fusions
performed. Scoliosis was the most common condition necessitating posterior
thoracic fusion. The first half of this article focuses on the indications for
thoracic and lumbar fusions; whereas, the second half of this article discusses
the trends in use of thoracic and lumbar spine fusions.
PMID- 9756974
TI - Thoracic and lumbar trauma: rationale for selecting the appropriate fusion
technnique.
AB - Despite recent advances in surgical techniques and instrumentation, two issues in
the treatment of thoracic and lumbar remain contested: (1) the indications for
surgical intervention; and (2) the optimal approach to obtain decompression,
realignment, and fusion of the disrupted segment (anterior, posterior, or
combined). Choosing among the options requires the ability to define accurately
the extent of the injury to both the structural and the neurologic elements of
the spine as well as an appreciation of the historic rationale of individual
treatment methods.
PMID- 9756975
TI - Thoracic and lumbar fusions for degenerative disorders: rationale for selecting
the appropriate fusion techniques.
AB - This article defines the indications for spinal fusion surgery based on the
current literature as well as a rationale for selecting the appropriate spinal
fusion techniques for the more common degenerative lumbar and thoracic
conditions.
PMID- 9756976
TI - Thoracic and lumbar deformity: rationale for selecting the appropriate fusion
technique (Anterior, posterior, and 360 degree).
AB - The rationale of anterior versus posterior, or combined fusion is discussed with
regards to different clinical diagnoses and situations. Factors involved in the
decision-making process include stability, magnitude of deformity, rigidity of
deformity, neurologic considerations, bone quality, and medical/metabolic
factors. Careful preoperative assessment and planning are required as well as
consideration for the patient's overall well being.
PMID- 9756977
TI - Clinical outcome after fusion of the thoracic or lumbar spine in the adult
patient.
AB - This article highlights those disease processes for which fusion is used most
frequently in the adult. Although the focus is on clinical outcome after fusion,
the indications and natural history of the process itself are also briefly
discussed to provide a comparative basis on which outcomes may be judged.
PMID- 9756979
TI - Octanol-water partition: searching for predictive models.
AB - The log n-octanol/water partition coefficient (log Po/w) still represents one of
the most informative physicochemical parameters available to medicinal chemists.
In the present work, principles, methodologies, and parameters are briefly
reviewed for a variety of models developed to predict this parameter based on
molecular structure. To include the developments of recent years, a total of more
than 40 different approaches are mentioned with relevant bibliography within four
major categories: group contribution methods, atomic contribution methods,
molecular methods, and other physicochemical methods. To underscore once more the
utility of this partition coefficient, a comprehensive and reevaluated
correlation between log Po/w and in vivo permeability data of rat brain
capillaries is included. Most deviants that fell below the trendline are those
that have been recently found to be substrates for P-glycoprotein, a multidrug
transporter that actively removes them from the brain. Accurate predictions of
log Po/w may necessitate many parameters, but there is mounting evidence that
molecular size and hydrogen bonding ability can account for a major part of the
variance. Our recently developed, molecular size-based approach is reviewed, and
it is argued that introduction of three-dimensionality allows the elimination of
many empirically derived fragment constants without a significant deterioration
of the predictive accuracy. A comparison of predictive power for six different
methods on 145 molecules of interest for medicinal chemists is also included.
PMID- 9756978
TI - 1 - 1. The chemistry and pharmacology of indole-3-carbinol (indole-3-methanol)
and 3-(methoxymethyl)indole. [Part I].
AB - Indole-3-carbinol (I3C) (2) is produced endogenously from naturally occurring
glucosinolates contained in a wide variety of plant food substances including
members of the family Cruciferae, and particularly members of the genus Brassica,
whenever they are crushed or cooked. The acid environment of the gut very
facilely converts it into a range of polyaromatic indolic compounds, e.g. (3,
4,5), which appear to be responsible for many of the physiological effects
observed following the ingestion of these foods. 3-(Methoxymethyl)indole (6) is
formed with great ease whenever 2 contacts methylating agents, including
methanol, and it is often found as a contaminant of 2. This contamination is
often not recognized or easily removed because of the great similarities of the
two in melting points and solubilities. However, their biological properties are
essentially identical. These so-called chemopreventive compounds are important
because of their enzyme induction and suppression, mutagenic, carcinogenic and,
particularly, antimutagenic and anticarcinogenic properties. The natural
occurrence, formation, preparation, identification, separation, quantification,
chemical transformations and general toxicological properties of these substances
are critically reviewed in detail in this paper of 146 references, the first of
two parts. The enzyme induction and suppression, mutagenic, antimutagenic,
mutagenic, anticarcinogenic and carcinogenic effects will be published later as
Part II. At the present time it appears that these have considerable potential as
natural prophylactic anticancer agents against certain common neoplasms,
especially inasmuch modern diets are increasingly deficient in these vegetable
derived substances.
PMID- 9756981
TI - Biosynthetic anthracyclines.
AB - This review summarizes the structure, the occurrence and the available data
concerning the bioactivity of biosynthetic anthracyclines. The anthracyclines
represent an important family of natural products produced by microorganisms of
Streptomyces and related genera and include clinically useful agents for the
medical treatment of human cancer. Chemically, the anthracyclines are glycosides
characterized by a quinone tetracyclic aglycone and one or more deoxysugar units,
mostly belonging to the L-hexopyranoside series, comprising generally an
aminosugar. The different compounds belonging to this family are structurally
related as they share a common biosynthetic pathway. Although some statements
concerning structure activity relationships and molecular requirements for
activity can be made, published data are not adequate for the comparative
evaluation of potential antitumor efficacy of biosynthetic anthracyclines. This
family of natural products is therefore still open for pharmacological
investigation.
PMID- 9756980
TI - Review of cardiovascular effects of fluoxetine, a selective serotonin reuptake
inhibitor, compared to tricyclic antidepressants.
AB - Fluoxetine is an antidepressant drug, a potent and specific inhibitor of
serotonin reuptake (SSRI). Evidence suggests that being compared with tricyclic
antidepressants, fluoxetine may cause significantly fewer anticholinergic,
antihistaminergic and cardiotoxic side effects in the treatment of major
depressive disorders. Chronic treatment with fluoxetine was not reported to
affect the electrocardiogram (ECG). There is no clinical evidence of conduction
delay and very little evidence of orthostatic hypotension. In the overdosed
patients fewer cardiac symptoms were reported than with tricyclic
antidepressants. However, dysrhythmia (atrial fibrillation and bradycardia) and
syncope associated with fluoxetine treatment and overdose were reported. Although
such reports have not been common, they do raise concerns. Thus we investigated
the direct cardiovascular effects of the fluoxetine in isolated heart
preparations and vessels of rats and rabbits. From 10(-6)M to 10(-4)M
concentrations fluoxetine showed cardiodepressant and vasodilatory effects. These
effects were similar to those of previously reported on tricyclic compounds. This
review is a brief summary of possible cardiovascular effects of fluoxetine and
other new SSRIs antidepressants from the literature based on experience of
clinical studies and our experiments with fluoxetine on isolated rat and rabbit
cardiac preparations and vessels. Possible explanations of the lower incidence of
cardiovascular complications with fluoxetine in humans and cardiodepressant
effects in vitro are discussed.
PMID- 9756982
TI - Glial cells potentiate kainate-induced neuronal death in a motoneuron-enriched
spinal coculture system.
AB - AMPA/kainate receptor-mediated excitotoxicity is believed to play a pathogenic
role in amyotrophic lateral sclerosis. To further characterize the mechanisms
involved in AMPA/kainate receptor-mediated motoneuron injury, we investigated the
influence of spinal glial cells on kainate-induced motoneuron death in vitro. A
motoneuron-enriched neuronal population was obtained from embryonic mouse spinal
cord by metrizamide density centrifugation. This population was cultured either
on a pre-established glial feeder layer of ventral spinal origin (coculture) or
in glia-free conditions (monoculture). Glial feeder layers significantly enhanced
basal survival of neurons, and supported neuronal differentiation as judged by
neuronal morphology and expression of the motoneuron markers peripherin and SMI
32. Neuronal vulnerability to kainate was two- to three-fold higher in coculture
than in monoculture, and increased significantly with time in coculture. The
effects of glial feeder layers on neuronal basal survival, differentiation and
kainate vulnerability were not mimicked by conditioned medium from glial cells.
The increase in neuronal kainate vulnerability with time in coculture was
associated with a marked rise in the proportion of cocultured neurons possessing
Ca2+-permeable AMPA/kainate receptors, as determined by kainate-activated Co2+
uptake. Neurons in monoculture were unstained by kainate-activated Co2+-uptake.
Neurons were immunoreactive to specific antibodies against the AMPA receptor
subunits GluR1 and GluR2 both in monoculture and coculture. This study indicates
that motoneuron differentiation in coculture is associated with increased
vulnerability to kainate and increased expression of Ca2+-permeable AMPA/kainate
receptors. In this paradigm glial cells support basal survival and
differentiation of neurons, but potentiate kainate-induced neuronal death.
PMID- 9756983
TI - Characterization of cDNAs encoding a new family of tetraspanins from schistosomes
-the Sj25 family.
AB - The tetraspanins, also known as members of the transmembrane 4 superfamily
(TM4SF), comprise an assemblage of surface antigens reported from mammalian and
other vertebrate cells, from schistosomes, from fruit flies and from
Caenorhabditis elegans. Tetraspanins are characterized by the presence of four
hydrophobic domains, which are presumed to be membrane-spanning, and specific
conserved motifs. A novel cDNA encoding a new tetraspanin, termed TE736
(tetraspanin 736), was isolated and characterized from the human blood fluke
Schistosoma japonicum. Nucleotide and deduced amino acid sequences of the cDNA
revealed that TE736 was similar to the previously characterized Sm23/Sj23/Sh23
species homologues and to Sj25/TM4 from schistosomes, and to other tetraspanins.
Comparison of hydropathicity profiles of TE736, Sj25/TM4 and two novel
tetraspanin-like sequences from S. mansoni showed that they contain four
potential transmembrane domains like other tetraspanins. Sequence alignments
showed there are four highly conserved, cysteine residues on the second predicted
extracellular loop of TE736. A phylogenetic comparison of the relationship of
approximately 30 tetraspanins from mammals and other groups revealed that TE736,
Sj25/TM4 and the two sequences from S. mansoni formed an independent family of
tetraspanins. We have termed these tetraspanins from schistosomes the Sj25
family. TE736 appeared to be encoded by a single gene and to be expressed in at
least two life cycle stages of S. japonicum.
PMID- 9756985
TI - Effects of ZD6169, a KATP channel opener, on bladder hyperactivity and spinal c
fos expression evoked by bladder irritation in rats.
AB - Cystometrographic recording and immunocytochemical techniques were used to
examine the effects of ZD6169, an ATP-sensitive K+-channel opener, and capsaicin,
an afferent neurotoxin, on urinary bladder hyperactivity and immediate early gene
expression in the spinal cord induced by acetic acid (0.25%) irritation of the
bladder. Chemical irritation of the bladder of the rat increased the frequency of
voiding reflexes by 8 fold and increased c-fos expression in neurons in the
dorsal commissure (DCM), sacral parasympathetic nucleus (SPN) as well as the
medial and lateral dorsal horn (MDH, LDH) of L6 and S1 segments of the spinal
cord. Pretreatment with ZD6169 (30 nM) for 1 h reduced the effect of acetic acid
on voiding frequency as reflected by an increase in the intercontraction interval
(ICI, 137+/-48% increase, P<0.05). ZD6169 also decreased the number of Fos
positive neurons in the L6 spinal cord, in the DCM (62.1+/-7.1% decrease), SPN
(48.8+/-7%), MDH (50+/-7.3%) and LDH regions (38. 8+/-10.5%). Similar reductions
were noted in the S1 spinal cord: 65. 1+/-10.8% in DCM, 53.8+/-11% in SPN, 56+/
10.4% in MDH and 25.3+/-18. 1% in LDH. Capsaicin pretreatment (125 mg/kg, s.c., 4
days prior to the experiments) also reduced bladder hyperactivity (550% increase
in ICI) and decreased the numbers of acetic acid-induced Fos positive neurons
78.8+/-6.3% in DCM, 73+/-7.8% in MDH, 59.2+/-16% in LDH and 45.2+/-17% in SPN of
L6 segment of the spinal cord. These results suggest that ZD6169 can influence
bladder hyperactivity by suppressing the firing of capsaicin-sensitive C-fiber
bladder afferents which are known to modulate the micturition reflex.
PMID- 9756984
TI - Sequence of the putative alanine racemase operon in Staphylococcus aureus:
insertional interruption of this operon reduces D-alanine substitution of
lipoteichoic acid and autolysis.
AB - A gene cluster comprising the alanine racemase gene alr was identified 5' to the
sigB operon in Staphylococcus aureus. It is flanked upstream by four ORFs of
which one shows similarity to the dpj gene of Escherichia coli, and downstream by
two ORFs of which the last shows similarity to the E. coli pemK gene. Preliminary
data suggest that the seven ORFs orf1-orf2-orf3-dpj-alr-orf6-pemK may form an
operon. Disruption of the proposed operon by insertional mutagenesis leads to a
drastic loss in the d-alanine (d-Ala) substitution of lipoteichoic acid and to
delayed autolysis, without affecting the d-Ala substitution of the wall teichoic
acid.
PMID- 9756986
TI - Adenosine A1 receptor activation inhibits LTP in sympathetic ganglia.
AB - The effects of adenosine on long-term potentiation of sympathetic ganglia was
studied in the isolated superior cervical ganglion of the rat, using
extracellularly recorded compound action potential as an index of synaptic
transmission. Adenosine in a small concentration (2 microM) blocked the post
tetanic potentiation without affecting long-term potentiation. Higher
concentrations blocked both responses with no significant effect on basal
transmission. The inhibitory effect appears to be due to activation of adenosine
A1 receptors. This was indicated by results from experiments with the A1 agonist
N6-cyclopentyladenosine (1 microM) which caused inhibition of the basal
transmission as well as long-term potentiation and post-tetanic potentiation.
This inhibition was readily antagonized by 8-phenyltheophylline (1 microM), an A1
receptor antagonist. A small enhancement of basal transmission was seen on
treatment with 8-phenyltheophylline. The inhibitory effect of N6
cyclopentyladenosine on long-term potentiation was totally prevented when the
Ca2+ concentration in the superfusate was doubled (from 2.2 to 4.4 mM). The
adenosine A2 receptor agonist 5'-(N-cyclopropyl)-carboxamidoadenosine (1 microM),
although caused a slight potentiation of basal transmission, had no significant
effect on the post-tetanic potentiation or long-term potentiation. The adenosine
transport inhibitors, dipyridamole (2 microM) and S-(4-nitorobenzyl)-6
thioinosine (2 microM) caused significant inhibition of the basal ganglionic
transmission without affecting post-tetanic potentiation or long-term
potentiation. The effect of dipyradimole on basal transmission was not
antagonized in the presence of 8-phenyltheophylline suggesting a non-specific
action. The results suggest that exogenous adenosine can inhibit both post
tetanic potentiation and long-term potentiation in sympathetic ganglia, probably
by activation of presynaptic A1 receptors. The results also suggest that
endogenous adenosine, which is probably released in minute amounts, may only
modulate basal transmission without influencing induction or maintenance of long
term potentiation in the superior cervical ganglion.
PMID- 9756987
TI - The region 3' to Calpha1 gene of human IG heavy chain displays a polymorphic
duplicated sequence and encodes an RNA associated with polysomes.
AB - A highly spread polymorphism flanking the 3. Calpha1 human IG heavy chain gene
was identified. This polymorphism allowed the detection of an internal
duplication within the 3' flanking region of both Calpha1 and Calpha2. This
region has a regulatory function with four enhancer structures also present at
the 3' end of the human Calpha2 as well as in that of mouse and rat single Calpha
genes. The 5682-bp sequence of clone lambdapl8 described here starts 3' of
Calpha1 and presents three open reading frames; one of them contains part of the
tandem repeats with the 20-bp consensus described previously that is expressed in
a poly(A)+ RNA and found in three dbEST clones of the human tonsillar cDNA
library. Here, we demonstrate that in the CLF1 B lymphoblastoid cell line, this
transcript is associated with polysomes. We also discuss the possibility of the
presence of a new regulatory gene that does not encode an immunoglobulin and maps
in the human IG heavy chain gene cluster.
PMID- 9756988
TI - The Tat protein of equine infectious anemia virus (EIAV) activates cellular gene
expression by read-through transcription.
AB - The Tat protein of equine infectious anemia virus, EIAV, was shown to augment
viral gene expression, presumably through interaction with the Tat responsive
element, TAR. Recently, cell-free polyadenylation assays suggested that
perturbation of the EIAV TAR secondary structure diminished polyadenylation
efficiency. The present study indicates that the EIAV TAR regulates the
efficiency of the 3'-end processing of viral RNA also in transfected cells.
Moreover, our data suggest that the provision of the EIAV Tat protein in trans
potentiates read-through transcription through the 3' viral long terminal repeat
(3' LTR), thus suggesting activation of downstream-located cellular genes.
PMID- 9756989
TI - Effects of neonatal focal cerebral hypoxia-ischemia on sleep-waking pattern, ECoG
power spectra and locomotor activity in the adult rat.
AB - The aim of this study was to determine the influence of neonatal focal cerebral
hypoxia-ischemia (HI) on sleep-waking pattern, electrocorticogram (ECoG) power
spectra and locomotor activity (LA) in adult Wistar rats. Seven-day old pups were
subjected to permanent unilateral ligation of the common carotid artery and
transient hypoxia (8% O2). At 10 weeks of age, the extent of brain damages was
evaluated by magnetic resonance imaging (MRI) and homogenous injured animals were
selected before chronic implantation of radiotelemetry device. Using a single
ECoG recording channel method, waking (W), paradoxical sleep (PS) and slow wave
sleep (SWS) were continuously recorded for 72 h and they were semi-automatically
analyzed off-line. We observed that neonatal HI triggers a cascade of events
leading, in adult rats, to brain dysfunction characterized by an increase in SWS
(55.0 vs. 40.2% in sham-operated rats, p<0.05) and a marked decrease in W phases
duration (43.4 vs. 51.5%, p<0.05) while PS was almost suppressed in HI rats (1.6
vs. 8.3%, p<0.05). In addition, power spectral analysis of ECoG revealed
significant (p<0.05) alteration in PS power density with a shift of the dominant
frequency peak (5.0 to 7.5 Hz for HI and sham-operated rats, respectively).
During the light period, we found that HI induced a pronounced reduction of LA (
30%, p<0.05). These results indicate that Wistar rats exposed to a neonatal
unilateral cerebral HI present significant ECoG activity, sleep-waking pattern
and behavioral disturbances when adults. However, it remains to establish whether
such alterations can be prevented by neuroprotective agents.
PMID- 9756990
TI - Cloning of mouse gamma-glutamyl hydrolase in the form of two cDNA variants with
different 5' ends and encoding alternate leader peptide sequences.
AB - Mouse-liver gamma-glutamyl hydrolase (GH) is a lysosomal endopeptidase with an
acid pH optimum that is activated by sulfhydryl compounds and preferentially
hydrolyzes the most proximal gamma-glutamyl linkage of longer chain
polyglutamates of folates and their analogues. We describe the cloning of this
mouse lysosomal cDNA enzyme from liver GH mRNA in the form of two cDNA variants
(1.295 and 1.268 kb in length) differing 14-fold (Variant I versus Variant II) in
relative frequency that exhibited 5'-end heterogeneity and encoded alternate
leader peptides. The 5' UTR in these variants also differs in length by 27
nucleotides. Otherwise, the ORF and 3' UTR in each case are the same. These cDNAs
encode a protein in which the deduced amino acid sequence shares 78.9 and 69. 1%
identity to rat and human GH sequences, respectively. Amino acid sequence
comparisons among the three species identified three conserved Asn sites and two
conserved Cys residues that may be sites of glycosylation and sulfhydryl compound
activation, respectively. Variant I GH mRNA was more abundant than Variant II GH
mRNA in all mouse tissues examined. Variant I GH mRNA levels were extremely high
in salivary gland, moderately high in kidney, liver, lung, stomach and uterus,
low in small intestine, brain and fetal liver and relatively rare in thymus,
spleen and skeletal muscle. Abundance of GH mRNA among tumors varied from low to
high, with no discernible correlation with their tissue of origin.
PMID- 9756991
TI - Lateralized effects of ethanol on aggression and serotonergic systems in Anolis
carolinensis.
AB - The lateralized effects of ethanol (ETOH) upon behavior and monoamine
biochemistry in the lizard, Anolis carolinensis, were examined. Eight adult male
anoles consumed solutions of 19% ethanol (ETOH) twice daily over the course of 18
days, while controls consumed water. ETOH decreased the use of the left eye/right
hemisphere, but not the right eye/left hemisphere, during territorial aggression
(p<0.05). During crossover (i.e., ETOH to water and vice versa) this effect was
reversible and replicable. Biochemically, an asymmetry was observed in 5-HT
levels in the raphe both in ETOH and controls. ETOH increased levels of serotonin
(5-HT; p<0.05), and 5-HIAA/5-HT ratios (p<0.05) in the raphe; serotonin levels in
several brain regions correlated with aggressive responses. These results suggest
that ETOH boosts 5-HT levels in animals subchronically exposed to ETOH. They
further suggest that asymmetry in endogenous 5-HT systems may account for the
asymmetrical regulation of aggression generally, and may explain the behavioral
effects of ETOH upon lateralized aggression.
PMID- 9756992
TI - Molecular cloning and sequence analysis of a chicken cDNA encoding tyrosinase
related protein-2/DOPAchrome tautomerase.
AB - We have cloned and sequenced a chicken cDNA encoding an l-DOPAchrome tautomerase
(DCT) from an embryonic melanocyte cDNA library. The chicken DCT gene encodes a
deduced protein of 516 amino acids (aas) and shares 69.2% and 69.9% aa sequence
identity with the deduced mouse and human DCT proteins, respectively. Northern
blot hybridisation analysis reveals a DCT transcript of 3.5kb in RNA from the
retinal pigment epithelium (RPE) of chick embryos. Genomic Southern blot
hybridisation analysis suggests that the chicken DCT gene consists of several
introns and spans between 15 and 30kb of the chicken genome. This study completes
the sequencing of all the members of the chicken tyrosinase-related protein gene
family and provides evidence that this gene family is conserved between avians
and mammals.
PMID- 9756993
TI - Cortical spreading depression activates trophic factor expression in neurons and
astrocytes and protects against subsequent focal brain ischemia.
AB - We recently reported that cortical spreading depression (CSD), used to
precondition rat brain, reduced cortical infarction volume resulting from focal
cerebral ischemia by middle cerebral artery occlusion (MCAO) 3 days later. The
mechanisms underlying this protective effect by CSD remains to be explored. In
this study, we confirm that CSD is neuroprotective when KCl is applied epidurally
rather than intracortically. Neocortical infarct volume was 101.3+/-48.5 mm3 and
45.3+/-44.1 mm3 in the sham and CSD group, respectively (p<0.05). Using image
analysis, we identified the cortical region spared from infarction by the prior
CSD. We then determined the distribution of brain-derived neurotrophic factor
(BDNF) and basic fibroblast growth factor (bFGF) mRNA and the time course of
their expression in groups of animals treated with CSD and their controls. We
also examined the response of astrocytes to CSD using glial fibrillary acidic
protein (GFAP) as a marker. In situ hybridization (done at 0, 3, 12, 24, 72 or
168 h after CSD) showed significant elevation of BDNF mRNA in the cortex
immediately after CSD in a distribution surrounding the spared cortex, while bFGF
mRNA rose 12 h after CSD and appeared more within the core of the ischemic
region. Immunohistochemistry (done at 1, 3 or 7 days after CSD) demonstrated GFAP
in the neocortex, with a peak at 3 days after CSD. Heat shock protein 72 (HSP72)
expression was not affected by CSD. We concluded that upregulation of trophic
factors and activation of glial cells may contribute to the neuroprotection
induced by CSD.
PMID- 9756994
TI - Characterization of the chicken interleukin-1beta converting enzyme (caspase-1)
cDNA and expression of caspase-1 mRNA in the hen.
AB - We have cloned and sequenced a chicken homolog to the mammalian interleukin-1beta
(IL-1beta)-converting enzyme (caspase-1) cDNA and have evaluated caspase-1 mRNA
expression in various tissues from the domestic hen, including ovarian follicle
granulosa and theca layers. The deduced amino acid (aa) sequence of chicken
caspase-1 is 44.9% identical to human caspase-1, and contains an active site
pentapeptide that is characteristic of the caspase family of cysteine proteases.
Of interest, however, is that the putative chicken caspase-1 cDNA is predicted to
encode a comparatively short (19aa) N-terminal prodomain, as well as two Cys
residues within the active pentapeptide (QC162C163RG) as compared to the QACRG
pentapeptide found in the mammalian caspase-1 sequence. While the chicken caspase
1 mRNA transcript is widely expressed among different tissues, levels are
particularly high in the bursa of Fabricius and comparatively low in ovarian
follicles at all stages of development. Finally, treatment of granulosa cells
with IL-1beta, the primary if not sole product of caspase-1 activity, fails to
either promote apoptotic cell death or enhance viability in granulosa cells.
Considering the relatively low levels of caspase-1 mRNA expression in ovarian
follicle tissues plus the inability of IL-1beta to alter granulosa cell
viability, in vitro, it is concluded that caspase-1 is not an integral part of
the apoptotic pathway in granulosa cells. However, the pattern of mRNA expression
is consistent with a requirement for caspase-1 mediated IL-1beta production in
chicken immune tissues.
PMID- 9756995
TI - Inhibition of spontaneous inhibitory postsynaptic currents (IPSC) by
noradrenaline in rat supraoptic neurons through presynaptic alpha2-adrenoceptors.
AB - It has been shown that noradrenergic activation has great influence on the
activities of hypothalamic supraoptic neurons. No direct evidence has been
reported on the presynaptic effects of adrenoceptors in the actions of
noradrenaline on supraoptic neurons, although postsynaptic mechanisms have been
studied extensively. In the present study, we explored presynaptic effects of
noradrenaline on the supraoptic neurons by measuring spontaneous inhibitory
postsynaptic currents (IPSC) with the whole-cell patch-clamp technique.
Noradrenaline reduced the frequency of IPSCs in a dose-dependent (10(-9) to 10(
3) M) and reversible manner. Noradrenaline did not affect the amplitude of IPSCs
at concentrations of 10(-9) to 10(-5) M, but reduced the amplitude of IPSCs at
high concentrations (10(-4) and 10(-3) M). The inhibitory effects of
noradrenaline were mimicked by the alpha2-agonist clonidine (10(-4) M), but not
by the alpha1-agonist methoxamine (10(-4) M) nor by the beta-agonist
isoproterenol (10(-4) M). Moreover, the inhibitory effects of noradrenaline on
IPSCs were blocked by the non-selective alpha antagonist phentolamine (10(-4) M)
or the selective alpha2-antagonist yohimbine (10(-4) M), but not by the alpha1
antagonist prazosin (10(-4) M). These results suggest that noradrena-line
inhibits release of GABA from the presynaptic GABAergic terminals of the
supraoptic neurons by activating presynaptic alpha2-adrenoceptors and such
presynaptic mechanisms may play a role in the excitatory control of SON neurons
by noradrenergic neurons.
PMID- 9756997
TI - A procedure for cloning genomic DNA fragments with increasing thermoresistance.
AB - Genomic DNAs have been cleaved by restriction or sonication, and the resulting
double-stranded fragments have been exposed to increasing temperatures. This
treatment may induce the helix-coil transition either in a single or in several
steps, depending on the size and composition of the duplexes. Eventually, a
critical temperature is reached at which each duplex melts completely and the two
constitutive single strands separate. A transition interval can thus be defined
for each duplex by the temperature at which the earliest strand separation takes
place and that at which the most resistant double-stranded core collapses. If
solutions containing a mixture of DNA duplexes are exposed to temperatures within
their transition intervals, three kinds of molecules should originate: (1)
duplexes that have not yet initiated the melting phase; (2) duplexes that have
undergone only partial melting; and (3) single strands that derive from fully
melted duplexes. If the heated solutions are quickly cooled to 0 degreesC, only
the molecules from the first two classes can be ligated to a compatibly ended
vector and cloned: class (1) are intact duplexes, and class (2) are molecules
that snap immediately back to fully duplex structures: both are double-stranded.
Conversely, the single strands of class (3) may not reanneal and thus be neither
ligated nor cloned. We have tested the procedure on restricted coliphage lambda
DNA, in view of its compartmentalized organization and known sequence. Then, we
have applied it to human genomic DNA fragmented by sonication. After cloning of
the available duplexes in a bacterial plasmid, libraries of molecules endowed
with a progressively higher thermoresistance can be prepared for thermodynamic
and genomic studies.
PMID- 9756996
TI - Molecular events after antisense inhibition of hMSH2 in a HeLa cell line.
AB - To establish a cause-effect relationship between the human mismatch repair
pathway deficiency and the observed phenotypes, a hMSH2 deficient HeLa cell line
(HeLa-MSH2-) was established by transfecting the HeLa cells with an antisense RNA
expression plasmid. The expression plasmid was constructed by inserting an 851 bp
fragment of hMSH2 cDNA into the polyclonal site of the vector pREP9 in a reversed
orientation. The production of the mismatch binding protein, hMSH2, was inhibited
in HeLa-MSH2- cells, as demonstrated by Western blotting and band shift assay of
its whole cell extract. The growth rate of this cell line was not different from
the parental HeLa cells soon after transfection. However, the rate was faster
after 10 subcultures. The spontaneous mutation frequency at the hypoxanthine
phosphoribosyltransferase (HPRT) locus increased markedly, but no N-methyl-N'
nitro-N-nitrosoguanidine (MNNG) tolerance appeared in this cell line. Our results
clearly demonstrated several molecular events happened after the inhibition of a
major mismatch recognition protein, hMSH2, in the mismatch repair pathway,
mimicking carcinogenesis processes.
PMID- 9756998
TI - Regulation of cytosol-nucleus pH gradients by K+/H+ exchange mechanism in the
nuclear envelope of neonatal rat astrocytes.
AB - In order to study the subcellular heterogeneity of intracellular H+ concentration
in reactive astrocytes, the pH in the nucleus and cytosol of cultured astrocytes
was measured using a confocal laser scanning microscope (CLSM) and pH indicator
dye, 5'(and 6')-carboxyseminaphthofluorescein (carboxy SNAFL-1). The change in
intracellular pH was indexed by the fluorescence ratio (F535/F610) at an
excitation wavelength of 514.5 nm. The in vitro fluorescence ratio increased as
pH decreased. This ratio in the nucleus was significantly lower than that in the
cytosol of astrocytes when perfused by HEPES-buffered Hanks' balanced salt
solution (HHBSS) at pH 7.4. Acid stimulations of cells (pH 5.0) raised the
fluorescence ratio in both nucleus and cytosol. However, the increase in the
fluorescence ratio of the nucleus was less than that of cytosol. Treatment with a
K+/H+ ionophore, nigericin (20 microM), reversibly nullified this cytosol-nucleus
pH gradient. These findings suggest that a buffering mechanism(s) for maintaining
of intracellular pH exists between the nucleus and cytosol, and a K+/H+ exchanger
may act on the nuclear envelope to eventuate intranuclear pH maintenance in the
living cells.
PMID- 9756999
TI - Comparative studies on genotoxicity and antigenotoxicity of natural and synthetic
beta-carotene stereoisomers.
AB - To evaluate the practical value of natural beta-carotene (NbetaC) and to
elucidate the apparent discrepancy between epidemiological observations and
intervention trials on the role of beta-carotene (betaC) in tumor prevention, the
genotoxicity and the antigenotoxicity of NbetaC and synthetic betaC crystal
(SbetaCC) stereoisomers were studied comparatively using chromosome aberration
analysis and the micronucleus test in human lymphocytes in vitro. NbetaC was
extracted from the halotolerant algae Dunaliella salina. The NbetaC crystal
(NbetaCC) preparation is about 70% all-trans (TbetaC) and 8% 9-cis (CbetaC). The
NbetaC oil (NbetaCO) preparation is about 40% all-trans and 38% 9-cis. SbetaCC is
more than 97% all-trans, and the 9-cis can not be detected. The mixture of betaC
(betaCM) preparation is 74% SbetaCC and 26% NbetaC. Our results show no
genotoxicity of 1-30 microg/ml NbetaCC, but this concentration of NbetaCC
inhibited significantly gamma-ray-induced micronucleus formation in human
lymphocytes in vitro. One to thirty microg/ml NbetaCO was most effective against
both gamma-ray-induced and spontaneous micronucleus formation. However, no
influence of NbetaCO on spontaneous chromosome aberrations in human lymphocytes
in vitro was observed. NbetaCO suppressed significantly mitomycin C (MMC)-induced
chromosome aberrations. One to thirty microg/ml SbetaCC induced a dose-dependent
increase in micronucleus frequency, and also inhibited gamma-ray-induced
micronucleus formation. No effect of betaCM on spontaneous chromosome aberrations
was found. One to thirty microg/ml betaCM is more effective against MMC-induced
chromosome aberrations than NbetaCO. These results suggest that CbetaC might play
a critical role in the genotoxicity and antigenotoxicity of SbetaCC and NbetaC.
The genotoxic activity of SbetaCC might be involved in carcinogenesis. NbetaC or
betaCM could be of practical value in tumor prevention and supplementary
treatment.
PMID- 9757000
TI - Establishing the Cryptosporidium parvum karyotype by NotI and SfiI restriction
analysis and Southern hybridization.
AB - The molecular karyotype of the coccidian parasite Cryptosporidium parvum has
proven difficult to study because chromosomes of similar sizes migrate together
when submitted to pulsed-field gel electrophoresis (PFGE). In the present work,
the karyotype was studied by restriction of chromosome-sized DNA with the rare
cutting enzymes NotI and SfiI, followed by PFGE separation of the restriction
fragments and Southern hybridization. These experiments showed that the C. parvum
karyotype is formed by eight chromosomes, ranging in size from approximately 0.95
to 1.45 million base pairs (Mbp), accounting for a genome size of 9.6Mbp. As a
first step towards the construction of a physical map of the C. parvum genome, a
total of 20 probes, including 16 genes and the ribosomal DNA (rDNA) sequence, was
mapped to intact chromosomes and to their restriction fragments. In this way, all
chromosomes, but one, were identified by specific markers. A comparison of
mapping data of homologous genes from different species belonging to the phylum
Apicomplexa showed differences in the distribution of rDNA sequences and in the
chromosomal localization of alpha- and beta-tubulin genes. The variation in
genome size among these parasites is also discussed.
PMID- 9757001
TI - Role of the subthalamo-nigral input in the control of amygdala-kindled seizures
in the rat.
AB - The substantia nigra pars reticulata (SNpr) is a critical site for the control of
epileptic seizures. Potentiation of the inhibitory GABAergic input from the
striatum to the SNpr suppresses primary or secondary generalized seizures in the
rat. The purpose of this study was to examine the possible involvement of the
excitatory glutamatergic input from the subthalamic nucleus to the SNpr in the
control of both the electroencephalographic and the motor components of amygdala
kindled seizures in the rat. Microinjections of either an N-methyl-D-aspartate
(NMDA) antagonist in the substantia nigra or a GABAA agonist in the subthalamic
nucleus, significantly reduced motor seizures but did not modified the
afterdischarges. These results provide evidence for the involvement of the
subthalamo-nigral projection in the modulation and the propagation of the motor
components of amygdala-kindled seizures.
PMID- 9757002
TI - Biomonitoring of workers exposed to lead. Genotoxic effects, its modulation by
polyvitamin treatment and evaluation of the induced radioresistance.
AB - A population monitoring study was performed, by using the micronucleus (MN) assay
in human peripheral lymphocytes, to investigate whether occupational exposure to
lead is genotoxic to workers. In addition to the exposed workers group, two more
groups were studied, an external group from a factory without exposure to lead
and an internal control group, from the same factory as the exposed workers, but
that were not directly exposed to lead. Measures of lead levels at working place
and in blood were calculated, and blood samples were collected to carry out a MN
study. The results from these studies indicate that the blood from workers
directly exposed contained high levels of lead, compared with the other groups,
and a significant increase in the frequency of both the total number of MN and
the number of binucleated cells carrying MN appeared. In addition, a study on the
antimutagenic effects of a polyvitamin rich diet was conducted by measuring the
frequency of MN after the workers had a four month daily intake of a polyvitamin
polymineral complex. These results clearly show a significant reduction of the MN
frequency evaluated after this treatment, obtaining values that were even lower
than those obtained in the internal control group. Finally, a challenge assay was
carried out to determine response to gamma-radiation as indication of any kind of
radiosensitivity or radioresistance. The results of this experiment did not show
any significant variation in the increase of the frequency of MN after challenge
irradiation in the lead exposed workers; nevertheless this increase was
significantly reduced in the sample obtained after the polyvitamin treatment
indicating a radioresistance response.
PMID- 9757003
TI - Identification of the start sites for the 1.9- and 1.4-kb rat transforming growth
factor-beta1 transcripts and their effect on translational efficiency.
AB - Three distinct transforming growth factor-beta1 (TGF-beta1) transcripts of 2.5,
1.9 and 1.4kb have been described, but the start sites and functional
significance of the shorter transcripts are unknown. Here, we have cloned and
sequenced a rat genomic fragment encoding approximately 1250 bases upstream of
the start of the TGF-beta1 open reading frame. Using a combination of
ribonuclease protection and 5' RACE-PCR analysis, we have mapped the start sites
for the two shorter TGF-beta1 transcripts in NRP152 cells, a rat prostatic
epithelial cell line that expresses all three transcripts at high levels. The 1.4
kb mRNA starts 25 bases upstream of the initiator AUG, whereas the 1.9-kb mRNA
has two start sites 366 and 401 bases upstream of the AUG. Polysome analysis of
the NRP152 cells indicates that the 1.9-kb transcript is very efficiently
translated, whereas the 2.5- and 1.4-kb transcripts appear to be poorly
translated. Differential regulation of TGF-beta1 transcript size may therefore
represent an important mechanism for regulating TGF-beta1 protein levels.
PMID- 9757004
TI - Progesterone withdrawal I: pro-convulsant effects.
AB - Pro-convulsant withdrawal properties have been reported for a variety of GABA
modulatory drugs, such as the benzodiazepines (BDZs, [S.E. File, The history of
BDZ dependence: a review of animal studies, Neurosci. Biobehav. Rev. 14 (1990)
135-146; P.R. Finley, P. E. Nolan, Precipitation of BDZ withdrawal following
sudden discontinuation of midazolam, DICP 23 (1989) 151-152]), barbiturates and
ethanol [N. Kokka, D.E. Sapp, U. Witte, R.W. Olsen, Sex differences in
sensitivity to pentylenetetrazol but not in GABAA receptor binding, Pharm.
Biochem. Behav. 43 (1992) 441-447]. In this report, we test the hypothesis that
pro-convulsant effects are produced by withdrawal from the GABA-modulatory
neurosteroid 3alpha-OH-5alpha-pregnan-20-one (3alpha,5alpha-THP) after sustained
exposure to elevated circulating levels of its parent compound progesterone (P).
Seizure activity was precipitated by picrotoxin or with the BDZ inverse agonist n
methyl-beta-carboline-3-carboxamide (beta-CC), and a seizure rating determined 24
h after abrupt discontinuation of P following a multiple withdrawal/chronic
administration paradigm. In some cases, a pseudopregnant rat model was employed
to produce increased ovarian production of P prior to withdrawal (ovariectomy).
Rats undergoing P withdrawal exhibited greater seizure-like activity than vehicle
treated controls, and received seizure scores in the same range as rats
undergoing BDZ withdrawal. Administration of a 5alpha-reductase blocker, MK-906,
along with P, prevented this pro-convulsant effect of P withdrawal, suggesting
that the GABA-modulatory 3alpha,5alpha-THP is the active compound responsible for
this withdrawal effect. Combined administration of P and diazepam produced
synergistic effects upon withdrawal and produced a seizure score higher than
observed after withdrawal from either agent alone. These results suggest that P
exhibits withdrawal properties via the neuroactive steroid 3alpha, 5alpha-THP,
that include exacerbation of seizure activity. These results may have clinical
relevance, as increased incidence and severity of seizures has been reported in
susceptible women during times of declining circulating levels of P across the
menstrual cycle [T. Backstrom, B. Zetterlund, S. Blom, M. Romano, Effects of
intravenous progesterone infusions on the epileptic discharge frequency in women
with partial epilepsy, Acta Neurol. Scand. 69 (1984) 240-248; A.G. Herzog,
Progesterone therapy in women with complex partial and secondary generalized
seizures, Neurology 45 (1995) 1660-1662].
PMID- 9757006
TI - Progesterone withdrawal. II: insensitivity to the sedative effects of a
benzodiazepine.
AB - Previous results from this lab have demonstrated that the GABA-modulatory steroid
3alpha-OH-5alpha-pregnan-20-one (3alpha, 5alpha-THP) exhibits withdrawal
properties, increasing anxiety [M.A. Gallo, S.S. Smith, Progesterone withdrawal
decreases latency to and increases duration of electrified prod burial: a
possible rat model of PMS anxiety, Pharmacol. Biochem. 46 (1993) 897-904.] and
seizure susceptibility [S.S. Smith, Q.H. Gong, F.-C. Hsu, R.S. Markowitz, J. M.H.
ffrench-Mullen, X. Li, GABAA receptor alpha4 subunit suppression prevents
withdrawal properties of an endogenous steroid, Nature 392 (1998) 926-930.] upon
abrupt discontinuation after chronic administration of its parent compound,
progesterone (P), in a manner similar to other GABA-modulatory drugs. Further, we
have demonstrated that withdrawal from P produces insensitivity to the
potentiating effects of the benzodiazepine (BDZ) lorazepam (LZM) on GABA-gated Cl
current [A.-M.N. Costa, K.T. Spence, S.S. Smith, J.M. H. ffrench-Mullen,
Withdrawal from the endogenous steroid progesterone results in GABAA currents
insensitive to BDZ modulation in rats CA1 hippocampus, J. Neurophysiology 74
(1995) 464-469; S.S. Smith, Q.H. Gong, F.-C. Hsu, R.S. Markowitz, J.M.H. ffrench
Mullen, X. Li, GABAA receptor alpha4 subunit suppression prevents withdrawal
properties of an endogenous steroid, Nature 392 (1998) 926-930.], assessed using
whole cell patch clamp procedures on pyramidal neurons acutely dissociated from
CA1 hippocampus. The purpose of the present study was to examine the withdrawal
effects of P on the sedative potency of LZM, tested behaviorally as the ability
to maintain position on a variable speed treadmill following LZM administration
(0.75 mg/kg). Both continuous (continuous release P capsule, single withdrawal)
as well as discontinuous (multiple P injection, multiple withdrawal) paradigms
were tested. Longer continuous release paradigms were more effective in
abolishing the sedative effects of LZM, without producing a change in baseline
response. The LZM insensitivity observed following the multiple withdrawal
paradigm was prevented by prior intraventricular administration of antisense
oligonucleotide against the alpha4 subunit of the GABAA receptor. These results
support the hypothesis that withdrawal from P decreases the behavioral response
to LZM as a direct result of increases in the alpha4 subunit of the GABAA
receptor. Withdrawal from P occurs endogenously during pre-menstrual and post
partum periods, when decreased response to BDZ has been reported.
PMID- 9757005
TI - Blue/white screening of recombinant plasmids in Gram-positive bacteria by
interruption of alkaline phosphatase gene (phoZ) expression.
AB - The process of screening bacterial transformants for recombinant plasmids is made
more rapid and simple by the use of vectors with visually detectable reporter
genes. In such systems, an alteration in colony phenotype occurs when a vector
borne indicator gene is interrupted with exogenous DNA. Although the lacZ system
has been used extensively for this purpose in E. coli, analogous systems for use
in Gram-positive bacteria remain uncommon. We have developed a Gram-positive
cloning vector that utilizes the interruption of an alkaline phosphatase gene,
phoZ, to identify recombinant plasmids. To facilitate introduction of foreign
DNA, a multiple cloning site (MCS) was inserted distal to the region coding for
the putative signal peptide of phoZ. Alkaline phosphatase expressed from the
derivative phoZ gene (phoZMCS) retained activity similar to that of the native
protein. The phoZMCS was transferred to pJS3, a well-characterized, high-copy
number, and broad-host-range plasmid, to produce pDC123. In pDC123, phoZMCS was
transcriptionally linked to the chloramphenicol acetyl transferase (cat) gene
under the control of the constitutively expressed tetM and cat promoters that
drive cat expression in pJS3. S. agalactiae (Group B streptococci, GBS), E.
faecalis, S. pyogenes, S. gordonii, and E. coli containing pDC123 displayed a
blue colonial phenotype on agar containing 5-bromo-4-chloro-3-indolyl phosphate
(X-p), which was readily distinguished from that of colonies containing the
parent plasmid pJS3. Introduction of foreign DNA into the MCS of phoZMCS produced
a white colonial phenotype in E. coli and GBS on agar containing X-p and allowed
discrimination between transformants containing recombinant plasmids versus those
maintaining self-annealed or uncut vector. We have used pDC123 to subclone the
cpsE gene from the plasmid pCER111, which carries a 9.0-kb fragment of the GBS
capsular polysaccharide synthesis locus. The plasmid pDC123 containing cpsE was
isolated by direct electroporation into GBS strain A909 with selection of
transformants containing recombinant plasmids achieved by 'blue/white' screening,
without the use of an intermediate host. This new cloning vector should improve
the efficiency of performing recombinant DNA experiments in Gram-positive
bacteria.
PMID- 9757007
TI - Use of alkaline comet assay (single cell gel electrophoresis technique) to detect
DNA damages in lymphocytes of operating room personnel occupationally exposed to
anaesthetic gases.
AB - Here, we report the possible in vivo induction DNA damage by exposure to various
waste anaesthetic gases such as halothane, nitrous oxide and isoflurane. The
alkaline comet assay (single cell gel electrophoresis technique) was carried out
on 66 operating room personnel (anaesthetists [doctors]; anaesthesia nurses and
anaesthesia unit technicians) currently employed at the Ankara Hospital in
Turkey. A significant increase in the number of lymphocytes with DNA migration
was observed in operating room personnel as compared to controls. Also, the
extent of damage in exposed smokers were significantly higher than exposed
nonsmokers. This study supports the existence of an association between DNA
damage and occupational exposure to inhalation anaesthetics.
PMID- 9757008
TI - Micronucleus formation in human amnion cells after exposure to 50 Hz MF applied
horizontally and vertically.
AB - Micronucleus (MN) induction as a genotoxic effect of extremely-low-frequency
electromagnetic fields (ELF-EMF, 50 Hz, 1 mT) was studied in human amniotic fluid
cells (AFC) after continuous exposure to magnetic fields (MF), oriented
horizontally and vertically with respect to the surface of the culture medium, at
different time points. To compare the effectiveness of different exposure
systems, a Helmholtz-coil system and a so-called Merritt-coil system was used. A
statistically significant increase in MN frequency could be detected in exposed
cells compared to controls after 72 h continuous exposure to MF applied
vertically in the Merritt-coil system, while no effect was found after exposure
in the Helmholtz-coil system. Furthermore, a significant increase in MN induction
occurred after 24, 48 and 72 h exposure to MF applied horizontally in the
Helmholtz-coil system in comparison to controls, whereas horizontally MF
generated in the Merritt-coil system induced no genotoxic effects. To exclude
suppression of indirect EMF-induced DNA-lesions, we studied MN formation in the
presence of N-Acetyl-p-aminophenol (APAP, Paracetamol(R)), which is an inhibitor
of DNA-repair mechanisms. We found a dose-dependent increase of MN formation in
APAP-treated AFC cells, but no significant further increase in MN frequency after
additional MF exposure. Therefore we conclude, that EMF-induced MN formation is
not caused by directly or indirectly induced clastogenic mechanisms. The obtained
results show that the orientation of MF with respect to the cell culture dish and
the physical condition of the exposure system is of major importance for the
induction of micronuclei in certain cell types. Therefore, the reason for
inconsistent results published in the literature may be caused by the variability
of exposure systems, the exposure conditions and the cell types used.
PMID- 9757009
TI - Isolation, characterisation and embryonic expression of WNT11, a gene which maps
to 11q13.5 and has possible roles in the development of skeleton, kidney and
lung.
AB - The Wnt gene family encodes a set of signalling molecules, thought to play an
important role in key processes of embryonic development. In vertebrates as a
whole 20 different Wnt genes have been identified to date, however, a complement
of only 16 have been identified in man and for some of these the complete coding
sequences are unavailable. We have recently isolated the full-length cDNA
sequence of a new human WNT gene, WNT11, investigated its genomic organisation
and performed detailed expression studies in early human embryos. These have
shown that the expression of human WNT11 is restricted to the perichondrium of
the developing skeleton, lung mesenchyme, the tips of the ureteric buds and other
areas of the urogenital system and the cortex of the adrenal gland. This, for the
first time, provides information for the embryonic expression of human WNT11. We
have mapped WNT11 to 11q13.5 and this together with its expression in the
perichondrium of the developing skeleton, makes it a plausible candidate gene for
HBM, which has been previously linked to markers from this region.
PMID- 9757010
TI - Maternal exposure to delta9-tetrahydrocannabinol facilitates morphine self
administration behavior and changes regional binding to central mu opioid
receptors in adult offspring female rats.
AB - Opiates and cannabinoids are among the most widely consumed habit-forming drugs
in humans. Several studies have demonstrated the existence of interactions
between both kind of drugs in a variety of effects and experimental models. The
present study has been focused to determine whether perinatal delta9
tetrahydrocannabinol (Delta9-THC) exposure affects the susceptibility to
reinforcing effects of morphine in adulthood and whether these potential changes
were accompanied by variations in mu opioid receptor binding in brain regions
related to drug reinforcement. Adult female rats born from mothers that were
daily treated with delta9-THC during gestation and lactation periods, exhibited a
statistically significant increase in the rate of acquisition of intravenous
morphine self-administration behavior when compared with females born from
vehicle-exposed mothers, an effect that did not exist in delta9-THC-exposed male
offspring. This increase was significantly greater on the last day of acquisition
period. There were not significant differences when the subjects were lever
pressing for food. In parallel, we have also examined the density of mu opioid
receptors in the brain of adult male and female offspring that were exposed to
Delta9-THC during the perinatal period. Collectively, perinatal exposure to
delta9-THC produced changes in mu opioid receptor binding that differed
regionally and that were mostly different as a function of sex. Thus, delta9-THC
exposed males exhibited a lower density for these receptors than their respective
oil-exposed controls in the caudate-putamen area as well as in the amygdala
(posteromedial cortical nucleus). On the contrary, delta9-THC-exposed females
exhibited higher density of these receptors than their respective oil-exposed
controls in the prefrontal cortex, the hippocampus (CA3 area), the amygdala
(posteromedial cortical nucleus), the ventral tegmental area and the
periaqueductal grey matter, whereas the binding was lower than control females
only in the lateral amygdala. These results support the notion that perinatal
delta9-THC exposure alters the susceptibility to morphine reinforcing effects in
adult female offspring, in parallel with changes in mu opioid receptor binding in
several brain regions.
PMID- 9757011
TI - Alzheimer's beta-amyloid peptides induce inflammatory cascade in human vascular
cells: the roles of cytokines and CD40.
AB - Accumulating evidence suggests that beta-amyloid (Abeta)-induced inflammatory
reactions may partially drive the pathogenesis of Alzheimer's disease (AD).
Recent data also implicate similar inflammatory processes in cerebral amyloid
angiopathy (CAA). To evaluate the roles of Abeta in the inflammatory processes in
vascular tissues, we have tested the ability of Abeta to trigger inflammatory
responses in cultured human vascular cells. We found that stimulation with Abeta
dose-dependently increased the expression of CD40, and secretion of interferon
gamma (IFN-gamma) and interleukin-1beta (IL-1beta) in endothelial cells. Abeta
also induced expression of IFN-gamma receptor (IFN-gammaR) both in endothelial
and smooth muscle cells. Characterization of the Abeta-induced inflammatory
responses in the vascular cells showed that the ligation of CD40 further
increased cytokine production and/or the expression of IFN-gammaR. Moreover, IL
1beta and IFN-gamma synergistically increased the Abeta-induced expression of
CD40 and IFN-gammaR. We have recently found that Abeta induces expression of
adhesion molecules, and that cytokine production and interaction of CD40-CD40
ligand (CD40L) further increase the Abeta-induced expression of adhesion
molecules in these same cells. These results suggest that Abeta can function as
an inflammatory stimulator to activate vascular cells and induces an auto
amplified inflammatory molecular cascade, through interactions among adhesion
molecules, CD40-CD40L and cytokines. Additionally, Abeta1-42, the more pathologic
form of Abeta, induces much stronger effects in endothelial cells than in smooth
muscle cells, while the reverse is true for Abeta1-40. Collectively, these
findings support the hypothesis that the Abeta-induced inflammatory responses in
vascular cells may play a significant role in the pathogenesis of CAA and AD.
PMID- 9757012
TI - An avian cDNA encoding a tyrosine-phosphorylated protein with PDZ, coiled-coil,
and SAM domains.
AB - Tyrosine phosphoproteins of size 115-120 kDa were purified from membranes of
chicken embryo fibroblasts (CEF) infected with Rous sarcoma virus (RSV). A mouse
was immunized with these proteins, and the immune serum was used to screen a CEF
cDNA expression library. A highly immunoreactive clone (KS5) was identified and
characterized. The cDNA of this clone is 2.3 kb in length with a short 5' UTR and
a single major open reading frame (ORF) encoding a polypeptide of 719 amino
acids, with a calculated molecular weight of 81.1 kDa. The encoded protein
contains an amino terminal PDZ domain, followed by a predicted coiled-coil
region, a PEST domain, and a carboxy-terminal SAM domain. Consensus sequence
motifs for tyrosine phosphorylation are also present, as are consensus sequences
for the binding of SH2 and PDZ domains. Antisera from mice immunized with
bacterially expressed fragments of the KS5 protein recognized proteins of size
230, 116, and 65 kDa in CEF. In other chicken embryo tissues, a 116-kDa species
was the predominant protein recognized. The 116-kDa species is tyrosine
phosphorylated in RSV-CEF. The presence of PDZ and SAM domains in the KS5 protein
suggests that it may act as a molecular adaptor, promoting and relaying
information in a signal transduction pathway. It is a member of a family of
related proteins, all of which have a highly conserved PDZ domain adjacent to a
coiled-coil region. Two other members of this family are the neuronal proteins
spinophilin (Allen, P.B., Ouimet, C.C., Greengard, P., 1997. Spinophilin, a novel
protein phosphatase 1 binding protein localized to dendritic spines. Proc. Natl.
Acad. Sci. USA 94, 9956-9961) and neurabin (Nakanishi, H., Obaishi, H., Satoh,
A., Wada, M., Mandai, K., Satoh, K., Nishioka, H., Matsuura, Y., Mizoguchi, A. ,
Takai, Y., 1997. Neurabin: A novel neural tissue-specific actin filament-binding
protein involved in neurite formation. J. Cell Biol. 139, 951-961).
PMID- 9757013
TI - Genotoxicity testing of wastewater sludge using the Allium cepa anaphase
telophase chromosome aberration assay.
AB - Wastewater sludges were analysed in the Allium cepa genotoxicity test. They were
sampled during three winter periods from three Danish municipal wastewater
treatment plants differing in size and industrial load. The toxicity of the
sludge was tested in the Allium root inhibition assay, and the results expressed
as EC30 and EC50 values showed that the toxicity could be positive correlated to
the industrial load. However, when genotoxicity was tested at concentrations
corresponding to the EC30 and EC50 values in the A. cepa anaphase-telophase
assay, only two sludge samples from the smallest plant with the lowest industrial
load induced significant chromosome aberrations. Concentrations of the heavy
metal's Pb, Ni, Cr, Zn, Cu, and Cd were also determined and could partly be
correlated with the toxicity of the sludge and the industrial load of the
treatment plants.
PMID- 9757014
TI - Mechanisms of ischemia-induced taurine release in mouse hippocampal slices.
AB - Taurine release in the hippocampus is markedly potentiated in various cell
damaging conditions, including ischemia and excitotoxic damage produced by
glutamate. The increase in the levels of taurine may provide an important
protective mechanism against excitotoxicity. The mechanisms of the enhanced
release were now studied in mouse hippocampal slices using a superfusion system.
The basal release of [3H]taurine was significantly increased in Na+-deficient
media in normal conditions, whereas the ischemia-evoked release was decreased,
indicating the participation of Na+-dependent transport processes. The
involvement of taurine transport carriers in the release was confirmed with the
structural analogs, hypotaurine and beta-alanine. These amino acids potentiated
the release by trans-stimulation in normoxia. In Na+-free conditions, this
heteroexchange was not discernible, the carriers not being functional without
Na+. In ischemia, the marked potentiation of taurine release by hypotaurine and
beta-alanine further indicates that the Na+-requiring transporters also operate
in ischemia. The effects of membrane disruption on taurine release due to
activation of phospholipases were estimated using phospholipase and protein
kinase inhibitors, which had no marked effects on hippocampal taurine release.
The chloride channel blockers, 4-acetamido-4'-isothiocyanostilbene-2, 2'
disulphonate (SITS) and diisothiocyanostilbene-2,2'-disulphonate (DIDS), reduced
the ischemia-induced release, suggesting that taurine diffusion through an anion
channel is partially responsible for the enhanced release in ischemia.
PMID- 9757015
TI - Genotoxicity tests for new chemicals in Germany: routine in vitro test systems.
AB - According to regulations in the European Union, new chemical substances must be
notified before they can be introduced onto the market. One of the prerequisites
for notification is that toxicological properties, including mutagenicity, are
examined. In this paper, a report on routine in vitro mutagenicity testing is
given for 776 new substances notified in Germany between 1982 and 1997. In
general, the methodological quality of testing was in line with internationally
accepted guidelines. Bacterial gene mutation tests (Bact) were conducted for
nearly all of the substances, 13.4% were positive. Of the Bact-positive
substances, 36 were also tested in the in vitro chromosomal aberration test
(CAbvit) and the mammalian cell gene mutation test (MCGM). Twenty-six of these
(72. 2%) were negative in both mammalian cell tests indicating that the genotoxic
potentials of the substances are not relevant for man. Of all new substances, 333
were tested in CAbvit, here the percentage of positive findings was 25.2%. More
than 80% of the in vitro clastogens were negative in the Bact. With respect to a
sensitive detection of genotoxic potentials of substances, the combination
'Bact+CAbvit' is appropriate for basic testing. In our database CHL cells were
more sensitive to clastogenic effects than other cell types. Only very few
clastogens were identified as 'high toxicity clastogens'. MCGM tests were
performed for 118 substances, quite often as follow-up in case of positive Bact
tests. In total, 12.7% of the substances were positive in the MCGM. However,
there was a clear difference in the frequencies of positive findings in HPRT
tests (5.5%) and mouse lymphoma assays (MLA; 37.0%). None of the MCGM-positive
substances was a 'unique positive', i.e., negative in Bact and CAbvit.
PMID- 9757016
TI - Multiple actions of the novel anticonvulsant drug topiramate in the rat subiculum
in vitro.
AB - We used an in vitro slice preparation to study whether and how the anticonvulsant
drug topiramate (TPM, 50-500 microM) modulates the excitability of rat subicular
neurons that generate action potential bursts mainly caused by voltage-dependent,
Na+-electrogenesis. Subiculum is a gating structure for outputs originating from
the hippocampus proper, and thus it may play a role in limbic seizures. In 28/45
neurons, TPM induced a steady hyperpolarization of the resting membrane potential
(RMP) that ranged between -2 and -16 mV and was associated with a 24-62% decrease
of the apparent membrane input resistance. TPM also depressed the ability of
these cells to generate action potential bursts in response to brief (5-150 ms)
depolarizing pulses; such an effect was characterized by an increase in the
amount of intracellular depolarizing current required for eliciting action
potential bursts, and it also occurred when the TPM-induced steady
hyperpolarization was compensated by injecting steady depolarizing current. In
addition TPM reduced by approx. 50% the regular action potential firing elicited
by prolonged (350-1000 ms) depolarizing pulses (n=15 of 27 neurons). Recovery of
the TPM-induced changes was not seen during washout for periods of 20-80 min
(n=7). Both the steady hyperpolarization of the RMP and the input resistance
decrease elicited by TPM were markedly reduced by the GABAA receptor antagonists
bicuculline methiodide (10 microM; n=6) or picrotoxin (100 microM; n=2); such an
effect was associated with a reduction, but not with blockade of the depressant
action exerted by TPM on burst generation. Our findings indicate that TPM reduces
subicular cell excitability, and modifies bursting ability and repetitive firing
properties. These effects may be ascribed to actions on voltage-gated, Na+
electrogenesis and GABAA receptors. We propose that these changes in excitability
may all contribute to the anticonvulsant action of TPM in limbic seizures that
occur in temporal lobe epilepsy patients.
PMID- 9757017
TI - The genomic organization of the human corticotropin-releasing factor type-1
receptor.
AB - We determined the genomic organization of human CRF type-1 receptor (hCRF-R1).
The gene coding for hCRF-R1 consists of at least 14 exons and spans over 20
kilobases. hCRF-R1's three reported isoforms originate from the same gene by
alternative splicing. The first hCRF-R1, which binds to CRF with the highest
affinity and transduces the most sensitive cAMP accumulation in response to CRF,
is encoded in a total of 13 exons, the only one excluded being exon 6. The second
isoform contains an additional 29-amino acid sequence which corresponds to exon
6. Unlike the first isoform, the third lacks a 40-amino acid sequence,
corresponding to exon 3. Exon-intron boundaries are the same as that of the
consensus sequence. Locations of introns in the coding sequence are similar to
human CRF-R1, rat CRF-R1, human CRF-R2alpha and others belonging to the human
glucagon receptor family.
PMID- 9757018
TI - Evaluation of a tissue homogenization technique that isolates nuclei for the in
vivo single cell gel electrophoresis (comet) assay: a collaborative study by five
laboratories.
AB - We evaluated a tissue homogenization technique that isolates nuclei for use in
the in vivo comet assay. Five laboratories independently tested the technique
using the liver, kidney, lung, spleen, and bone marrow of untreated and mutagen
treated male CD-1 mice. The direct mutagen methylmethanesulfonate (MMS) or the
promutagen diethylnitrosamine (DEN) were injected intraperitoneally at maximum
tolerated doses. Three and twenty-four hours later, the organs were removed and,
except for bone marrow, were minced and homogenized and a nuclear suspension was
prepared. The nuclear suspensions and bone marrow cells were used in the comet
assay. None of the nuclear suspensions from the non-treated mice induced a
positive response. All nuclear suspensions derived from the MMS-treated mice and
those of the liver, kidney, and lung from DEN-treated mice induced positive
responses in all the laboratories similarly. Reproducibility was demonstrated by
five replicate studies in one laboratory. Furthermore, the organ-specific
responses to MMS and DEN reflected the characteristic genotoxicity of the
chemicals. We concluded from these results that the homogenization technique is a
valid one to be used for mouse organs in the in vivo comet assay.
PMID- 9757019
TI - Adrenal steroid regulation of central angiotensin II receptor subtypes and
oxytocin receptors in rat brain.
AB - The neuropeptides angiotensin II (AngII) and oxytocin (OT) play important but
opposing roles in the regulation of sodium appetite in the rat, AngII as a
stimulatory peptide and OT as an inhibitory peptide. Adrenal steroids increase
the density of AngII receptors in brain following in vivo administration,
although the neuroanatomical and subtype specificity have not been thoroughly
examined. Furthermore, previous studies demonstrate that adrenalectomy (ADX)
leads to a reduction in OT receptors, although regions associated with sodium
appetite remain to be examined. In the present study, quantitative receptor
autoradiography was used to locate regions where perturbations in circulating
adrenal steroids affect the density of oxytocin receptors and the angiotensin
receptor subtypes AT1 and AT2. The results show that ADX results in a small, but
significant decrease in AT1 expression in the paraventricular nucleus of the
hypothalamus, subfornical organ, and the area postrema. That this effect is
reversed by either aldosterone or low-dose corticosterone replacement suggests
that occupancy of the mineralocorticoid receptor is responsible for the steroid
effect. No changes were observed in AT2 or OT receptors in nuclei associated with
sodium appetite, indicating that perturbations in adrenal steroids did not affect
these receptors in brain regions implicated in the control of salt appetite.
PMID- 9757020
TI - The antioxidant defences of brain mitochondria during short-term forebrain
ischemia and recirculation in the rat.
AB - This study evaluated changes in the antioxidant defences of mitochondria induced
by 30 min of forebrain ischemia and recirculation up to 24 h in rats. Following
treatment, mitochondria were isolated from two brain subregions: the dorsolateral
striatum, an area in which there is loss of most neurons, and the paramedian
cortex in which most neurons are resistant to damage. During ischemia and the
first few hours of recirculation, the mitochondrial defences were largely
preserved based on measurements of the activities of the enzymes, superoxide
dismutase, glutathione peroxidase and glutathione reductase, as well as the
response of the mitochondria to a subsequent exposure to H2O2 in vitro. However,
some moderate changes were detected, particularly in the mitochondria from the
dorsolateral striatum. A decrease of 30% in the activity of superoxide dismutase
was seen at the conclusion of the ischemic period and a small increase in
susceptibility to changes induced by H2O2 was detected during early
recirculation. This latter change preceded and possibly contributed to the
development of an impairment of respiratory function detected in mitochondria
from the dorsolateral striatum at 3 h of recirculation. At 24 h of recirculation,
larger changes were seen in the activities of all three of the enzymes in
mitochondria from the dorsolateral striatum but not the paramedian cortex that
was associated with progression to advanced neuronal damage in the former
subregion.
PMID- 9757021
TI - Neonatal primary neuronal death induced by capsaicin and axotomy involves an
apoptotic mechanism.
AB - To clarify the mechanism of capsaicin-induced primary neuronal cell death,
newborn and adult rats were given a subcutaneous injection of capsaicin (50
mg/kg). Neonatal capsaicin injection induced neuronal apoptosis in the trigeminal
ganglion. Apoptotic neurons had peripheral stacks of long parallel endoplasmic
reticulum that are characteristic to primary neurons of the B-type, and exhibited
nucleoplasmic condensation, nuclear shrinkage and cytoplasmic fragmentation.
Light microscopically, apoptotic neurons exhibited a sign of DNA fragmentation as
revealed by a nick end labelling method. The proportion of apoptotic cells was
quite low during the first 12 h after capsaicin injection (<1%), rapidly increase
to 10.44% by 24 h, and decreased to 0.29% by 48 h. Normal and vehicle control
levels of apoptosis were <1%. Nerve growth factor (NGF, 0.5 mg/kg) simultaneously
administered with capsaicin reduced the incidence of apoptosis by about 35% at 24
h post-injection. Neonatal transection of the infraorbital nerve induced neuronal
apoptosis similar to that produced by the neonatal capsaicin in the maxillary
division of the trigeminal ganglion. Unlike capsaicin, however, the neurotomy
induced apoptosis was seen in neurons of both the A- and B-types. Neither the
capsaicin injection nor the neurotomy induced apoptosis in adult rats, though
mitochondrial swelling similar to that seen at 0.5 h after neonatal capsaicin was
observed after capsaicin injection in adults. The results indicate that the
capsaicin-induced and nerve injury-induced primary neuronal damages in newborn
rats share a common final pathway, apoptosis.
PMID- 9757022
TI - Tissue-specific enhancement and restriction of galanin gene expression in
transgenic mice by 5' flanking sequences.
AB - Galanin (GAL) is a 29/30 amino acid residue neuropeptide that regulates a wide
variety of neuroendocrine functions. Galanin is expressed in specific populations
of neurons in the hypothalamus and other regions of the brain and in numerous
peripheral sites. Previous studies in which galanin-reporter genes were
transfected into neural crest-derived neuroblastoma and other tumor cells
indicated that cell-specific galanin expression is controlled by gene elements on
the 5' flanking sequence which enhance and restrict transcriptional activity. To
determine how the gene sequences act in vivo, we first determined the
distribution of endogenous galanin gene expression in normal mice. Galanin mRNA
was detected in several parts of the central nervous system (CNS), and in several
peripheral organs, including the pituitary, pancreas, small and large intestine,
adrenal gland, lung, tongue, testes, ovary-fallopian tubes, and uterus, but not
at detectable levels in the heart, liver, kidney, urinary bladder or skeletal
muscle. We then created several lines of transgenic mice which contained either 5
or 0.131 kilobases (kb) of the bovine galanin gene 5' flanking sequence fused to
the luciferase (luc) reporter gene (5GAL-luc vs. 0.1GAL-luc mice, respectively)
and compared luciferase activity in these and other organs. In some regions of
the CNS that expressed high amounts of galanin mRNA, such as the spinal cord,
hypothalamus, thalamus, and medulla, transgene expression was significantly
higher in 5GAL-luc vs. 0.1GAL-luc mice, whereas in certain other regions of the
brain and in all peripheral organs, the ratio was strikingly reversed. It is
concluded that 5 kb of flanking sequence contains elements that mediate basal
transcriptional activity in certain parts of the CNS, but also contains sequences
that restrict expression in many tissues. However, because the larger transgene
was expressed at very low levels in some peripheral sites of high galanin
expression such as the pituitary, pancreas, adrenal gland, and intestine, it is
concluded that sequences on the 5 kb transgene are not sufficient to direct
expression to these peripheral tissues in mice.
PMID- 9757023
TI - Homo- and heterosynaptic long-term potentiation in the medial cortex of the
turtle brain in vitro.
AB - Long-term potentiation of excitatory synaptic transmission was studied in an in
vitro turtle brain that manifests spontaneous electrocorticogram activity. We
show that in the turtle medial cortex, there is evidence of homosynaptic long
term potentiation in the septum-medial cortex pathway. This potentiation has two
components, one dependent on NMDA receptor activation and the other independent
of this receptor and suppressed by nifedipine, an antagonist of voltage-dependent
Ca2+ channels (VDCCs), as occurs in the CA1 of rat hippocampus. Heterosynaptic
long-term potentiation was also found in the medial cortex, as a tetanus in the
septum also increased the cortico medial-cortico medial response. The
intracellular response of pyramidal cells showed that the medial cortex EPSP
increased its amplitude paripassu with an increase in the response of evoked
field potential after tetanic stimulation in the septum.
PMID- 9757024
TI - Hyperoxia increases paradoxical sleep rhythm in the pontine cat.
AB - Pontine cat is an ectothermic preparation, whose central temperature can
artificially be lowered from 36 degrees C to 26 degrees C; this gradual
hypothermia is accompanied by a dramatic increase in paradoxical sleep (PS). Two
main hypotheses might explain this result: executive systems of PS might be
switched on gradually by cold-sensitive thermodetectors, whereas inhibitory
monoaminergic mechanisms appear to be warm-sensitive. On the other hand, energy
saving mechanisms peculiar to hypothermia might promote PS appearance. Indeed, in
normal animals, PS is selectively suppressed both by hyperthermia and hypoxia.
The inhibitory effect of hypoxia might explain why hypothermia, which protects
the brain against hypoxic alterations, might facilitate PS. If this last
hypothesis is correct, the putative increase in cerebral oxygen supply might
increase PS. For this reason, we submitted eight pontine carotid-deafferented
cats, kept at the same central temperature (34 +/- 0.5 degrees C: temperature
clamp) to periodic hyperoxia (PaO2 = 58 +/- 7 kPa) or room air (PaO2 = 17 +/- 2
kPa) alternatively during 4- or 12-h periods. Hyperoxia induced an 85% increase
in PS, mainly due to an increase in PS rhythm (PS cycle duration was 65 +/- 4 min
in normoxia and 45 +/- 4 min in hyperoxia, p<0.0001). In five animals, after
hyperoxia, PS cycle returned gradually back to control values in 4 to 12 h. These
findings show that PS is exquisitely sensitive to conditions that impair
oxidative metabolism. The role of cholinergic executive PS systems as putative
metabolic-sensitive neurons remains to be established.
PMID- 9757025
TI - Preproenkephalin gene expression and [Met5]-enkephalin levels in the developing
rat heart.
AB - [Met5]-enkephalin, encoded by the preproenkephalin (PPE) gene, serves as a growth
factor (opioid growth factor, OGF) during cardiac development in addition to its
role as a neuroregulator. This study examined the ontogeny and relationship of
gene and peptide expression in the mammalian heart during late embryonic,
preweaning, and postweaning periods. Values for PPE mRNA of hearts in rats from
embryonic day 16 (E16) to postnatal day 1 were 33 to 50% of levels found in
adults. Adult values for the mature heart were comparable to those in the
caudate, an area of the rat brain rich in PPE mRNA. Message gradually decreased
during the first postnatal week to 10% of adult values and remained so until
weaning. PPE mRNA on days 35 and 50 were three- and sevenfold, respectively,
higher than at 21 days, and in adults was more than 50% greater than at day 50.
Message for PPE in neonatal heart was regulated rapidly and in a sustained
fashion by excess opioid agonist (OGF) or blockade of opioid-receptor
interaction. [Met5]-enkephalin levels increased sevenfold between E18 and E20,
and another 1.6-fold until birth. Having reached a zenith in the neonate, values
for enkephalin-like peptide decreased gradually through the 2nd postnatal week,
and were extremely low in adulthood. Indeed, a 43-fold difference in peptide
levels was detected between neonatal and adult rat heart. These data provide
evidence for the expression of a tightly regulated and distinct growth factor
(OGF) during the crucial periods of cell proliferation and differentiation in the
mammalian heart, and reveal that the source of OGF is autocrine and/or paracrine.
PMID- 9757026
TI - Amyloid beta-peptide induces apoptosis-related events in synapses and dendrites.
AB - Synapse loss in cerebral cortex and hippocampus is a prominent feature of
Alzheimer's disease (AD) that is correlated with cognitive impairment.
Postsynaptic regions of dendrites are subjected to particularly high levels of
calcium influx and oxidative stress as a result of local activation of glutamate
receptors, and are therefore likely to be sites at which neurodegenerative
processes are initiated in AD. Data suggest that neurons may die in AD by a
process called apoptosis which involves a stereotyped series of biochemical
changes that culminate in nuclear fragmentation, and that amyloid beta-peptide
(Abeta) may play a role in such apoptosis. We now report that Abeta induces
apoptosis-related biochemical changes in cortical synaptosomes, and in dendrites
of cultured hippocampal neurons. Exposure of synaptosomes to Abeta resulted in
loss of membrane phospholipid asymmetry, caspase activation, and mitochondrial
membrane depolarization. Cytosolic extracts from synaptosomes exposed to Abeta
induced chromatin condensation and fragmentation in isolated nuclei indicating
that signals capable of inducing nuclear apoptosis can be generated locally in
synapses. Exposure of cultured hippocampal neurons to Abeta resulted in caspase
activation and mitochondrial membrane depolarization in dendrites and cell
bodies. A caspase inhibitor prevented Abeta-induced mitochondrial membrane
depolarization in synaptosomes, and mitochondrial membrane depolarization and
nuclear apoptosis in cultured hippocampal neurons. Collectively, the data
demonstrate that apoptotic biochemical cascades can be activated in synapses and
dendrites by Abeta, and suggest that such 'synaptic apoptosis' may contribute to
synaptic dysfunction and degeneration in AD.
PMID- 9757027
TI - Changes in proliferating cell nuclear antigen, a protein involved in DNA repair,
in vulnerable hippocampal neurons following global cerebral ischemia.
AB - Proliferating cell nuclear antigen (PCNA) is required for completion of the DNA
synthesis step of DNA replication as well as nucleotide excision repair (NER) of
damaged DNA. We investigated the expression of PCNA mRNA and the levels of PCNA
protein in the adult rat hippocampus following normo- and hypothermic global
forebrain ischemia. Hypothermia protected the CA1 neurons from ischemic damage. A
constitutive expression of PCNA mRNA and protein was detected in all hippocampal
subfields, as well as in other brain regions. During reperfusion, PCNA mRNA
levels were up-regulated in the vulnerable CA1 subfield at 36 h following
normothermic ischemia. In hypothermia, this induction appeared already after 18
h. Following normothermic ischemia, nuclear PCNA immunoreactivity was largely
abolished during reperfusion in the vulnerable CA1 neurons, prior to cell death.
In contrast, total PCNA protein content of this region, as measured by Western
blotting, remained largely unchanged. In the CA3 region, a transient decrease in
nuclear PCNA immunoreactivity was observed. In the dentate gyrus region, no down
regulation of nuclear or total PCNA protein was observed during reperfusion.
Following hypothermic ischemia, the PCNA protein levels did not decrease in any
of the hippocampal subregions. In contrast, no change in the levels of Ref-1, a
protein involved in base excision DNA repair (BER), was observed following normo-
or hypothermic ischemia. Our findings indicate an altered functional state of
PCNA protein in the ischemia-sensitive CA1 neurons suggesting that DNA repair
processes are affected in these post-mitotic cells following ischemia. Impaired
DNA repair may play a role in the development of postischemic neuronal damage.
PMID- 9757028
TI - Neuroprotection by delayed administration of topiramate in a rat model of middle
cerebral artery embolization.
AB - Because topiramate (TPM) suppresses voltage-sensitive Na+ channels and non-N
methyl-D-aspartate (NMDA) receptors and enhances gamma-aminobutyric acid (GABA)
mediated inhibition, we tested whether it would protect against cerebral
ischemia. The right middle cerebral artery (MCA) was embolized by an intra
arterial injection of autogenous thrombus. Two hours after thrombus injection,
animals received intra-peritoneal injections (i.p.) of normal saline as control
(n=6) or alternatively, a low- (20 mg/kg, i.p., n=6) or high-dose (40 mg/kg,
i.p., n=6) of TPM. Neurological deficit was scored at 2 h and 24 h following the
ischemic insult. The animals were sacrificed 24 h after ischemia and the coronal
brain sections were stained with 2% 2,3,5-triphenyltetrazolium chloride (TTC) for
determination of the percentage of infarct volume. Administration of TPM
significantly improved the 24-h neurological deficit scores (low dose, 1.75+/
0.5; high dose, 1.17+/-0.41; p<0.05 for both doses). A reduction in the
percentage of infarct volume (low dose, 22.9+/-8.9%, p=0.002; high dose 7.6+/
3.4%, p<0.001) was seen when compared to the controls (infarct size, 54.2+/-9.0%;
neurobehavior score, 2. 67+/-0.52). Treatment with TPM at the higher dose induced
more neuroprotection than that at the lower dose (p<0.05). Thus, treatment with
TPM resulted in a dose- and use-dependent neuroprotective effect, when used 2 h
after MCA embolization in a rat model of focal ischemia.
PMID- 9757029
TI - Regulation of PAX-6 gene transcription: alternate promoter usage in human brain.
AB - We have isolated and characterized the 5'-flanking regulatory region of the human
PAX-6 gene. Mapping of transcription initiation sites revealed the existence of
an additional non-coding 5' exon, exon 1A. Functional analyses indicated that PAX
6 transcription is regulated by two distinct promoters, A and B, resulting in
alternative transcription of exon 1A or 1B and joint transcription of exons 2 to
13. While a single initiation site was identified for exon 1A, transcription of
exon 1B appears to be initiated from more than one site downstream of the
promoter B-associated TATA motif. Multiple potential binding sites for
transcription factors were found in the regions of promoter A and B. Although a
1.1-kb fragment of promoter A and a 1.5 kb fragment of promoter B, which had been
fused to a reporter gene and transiently expressed in cell lines, displayed
constitutive promoter activity, transcription of PAX-6 driven by promoter B was
considerably higher than by promoter A in various regions of human postmortem
brain. Transcript PAX-6B was primarily expressed in cerebellar cortex, whereas
relatively low concentrations were detected in other brain areas. Functional
dissection by serial deletions revealed several clusters of both activating
elements and cell-selective silencers within the regulatory regions upstream of
exon 1A and 1B. Coexpression of the promoter B constructs with a vector
expressing PAX-6 modulated promoter B activity, thus indicating autoregulation by
PAX-6 transcription. In conclusion, our findings suggest that PAX-6 transcription
is regulated by alternate usage of promoter A and B, and that in adult human
brain expression of PAX-6 is primarily controlled by promoter B. Alternate
promoter usage and differential PAX-6 transcription are likely to play a critical
role in brain development and neuroplasticity.
PMID- 9757030
TI - Fatty acid incorporation depicts brain activity in a rat model of Parkinson's
disease.
AB - Following pulse labeling with [3H]arachidonic acid ([3H]AA), its incorporation
pattern in brain reflects regional changes in neurotransmitter signal
transduction using phospholipase A2, that is, functional activity. In a rat model
of Parkinson's disease, unilateral 6-hydroxydopamine lesion in the substantia
nigra, [3H]AA acid incorporation from blood was increased in cerebral cortex,
caudate putamen, globus pallidus, entopeduncular nucleus, subthalamic nucleus and
substantia nigra pars reticulata ipsilateral to the lesion. This increased [3H]AA
incorporation likely reflects disinhibition of basal ganglia and cortical
circuits secondary to absent inhibitory nigrostriatal dopaminergic input.
PMID- 9757031
TI - Respiratory responses to chemical stimulation of the parabrachial nuclear complex
in the rabbit.
AB - The respiratory role of the parabrachial nuclear complex (PNC) was investigated
in alpha-chloralose-urethane anesthetized, vagotomized, paralysed and
artificially ventilated rabbits by means of unilateral microinjections (10-20 nl)
of 20 mM dl-homocysteic acid. Chemical stimulation elicited three main types of
site-specific respiratory effects: excitatory, apneustic and inhibitory
responses. The results suggest that the PNC plays a complex role in the control
of breathing.
PMID- 9757032
TI - Learning impairments caused by lesions to the pedunculopontine tegmental nucleus:
an artifact of anxiety?
AB - Bilateral N-methyl-d-aspartate lesions of the pedunculopontine tegmental nucleus
(PPTg) blocked the acquisition of a delayed non-matching to position task (DNMP)
performed in a T-maze. This acquisition impairment, however, was reversed by pre
testing injections of diazepam (1 mg/kg). These results, in addition to the
finding that PPTg lesions elevated anxiety as measured by the elevated plus maze,
suggest that PPTg is not involved in learning or memory, but in the regulation of
anxiety.
PMID- 9757033
TI - Cloning experiments and developmental expression of both melatonin receptor Mel1A
mRNA and melatonin binding sites in the Syrian hamster suprachiasmatic nuclei.
AB - The suprachiasmatic nuclei (SCN) are implicated in the control of circadian
biological rhythms, and especially the melatonin nocturnal synthesis. In numerous
rodents, melatonin has been shown to feed back on the SCN activity through high
affinity receptors. In contrast, Syrian hamster SCN activity is unresponsive to
melatonin injections. As this lack of effect could be linked to a developmental
loss of SCN melatonin receptors, the goals of the present study were 1) to report
in Syrian hamster SCN, and pars tuberalis (PT) as a control, a complete pattern
of the postnatal (PN) development of the melatonin receptor density and 2) to
investigate whether the regulation of the Mel1a mRNA expression could be
implicated in the post natal variations of the melatonin binding capacities. We
first subcloned by PCR a partial cDNA encoding the Mel1a receptor from Syrian
hamster SCN. Subsequent quantification of Mel1a mRNA expression and melatonin
receptor density revealed that in the PT and SCN, both Mel1a mRNA expression and
melatonin binding capacities declined abruptly between PN 0 and PN 8. Afterwards,
in the PT, both parameters went up until they got stabilized in adulthood.
Therefore, in the PT, post natal melatonin receptor density variations were
highly correlated with post natal variations of the Mel1a mRNA expression. In the
SCN, after PN 8, the melatonin receptor density followed its drop and then
declined by more than 92% between post natal day 0 (PN 0) and PN 60 (12.11+/-0.
27 vs. 0.94+/-0.08 fmol/mg protein at PN 0 and PN 60 respectively). In contrast,
Mel1a mRNA expression only slightly went down after PN 8 and got stabilized in
adult age at 42% of the birth day expression level. These results show that
Syrian hamster SCN undergo a dramatic post natal loss of their melatonin
receptors that could explain the lack of effect of melatonin injections on SCN
circadian activity. Furthermore, this SCN binding capacities decline could not be
attributed to an inhibition of the mRNA expression, but rather to a post
transcriptional blockade of the Mel1a receptor expression.
PMID- 9757034
TI - Inhibitory action of CGS 21680 on cerebral cortical neurons is antagonized by
bicuculline and picrotoxin-is GABA involved?
AB - The possibility of an involvement of endogenously released GABA in the inhibitory
actions of A1 and A2a adenosine receptor agonists on rat cerebral cortical
neurons discharges was examined using the GABAA antagonists bicuculline and
picrotoxin. The A1 agonist N6-cyclopentyladenosine (CPA), the A2a agonist CGS
21680 and the non-selective receptor agonist, adenosine, depressed neuronal
firing. Applications of bicuculline or picrotoxin enhanced the spontaneous firing
rate of cortical neurons, indicating the presence of ongoing GABA-ergic
inhibition. Antagonism of GABAA receptors blocked the depressant effects of CGS
21680 on neuronal firing; was without effect on CPA-evoked inhibitions and tended
to reduce the duration of adenosine-evoked inhibitions. These results suggest
that the depressant effects of A2a receptor activation are due to an increase in
GABA-ergic inhibition, likely as a consequence of increased GABA release. GABA
does not appear to be involved in adenosine A1 receptor-mediated inhibition of
neuronal firing.
PMID- 9757035
TI - 1,25-Dihydroxyvitamin D3 receptors in the central nervous system of the rat
embryo.
AB - We have mapped areas within the central nervous system (CNS) of the developing
fetal rat which immunostain for the 1,25-dihydroxyvitamin D3 receptor (VDR). The
VDR was detected from days 12 to 21 of gestation throughout the CNS;
immunostaining was particularly intense in the neuroepithelium and within the
differentiating fields of various areas of the brain. Cells within the spinal
cord, dorsal root, and other ganglia exhibited positive staining for the VDR. The
intensity of staining for the VDR diminished or disappeared in the
neuroepithelium throughout the CNS during the later days of development, while in
the differentiating fields single VDR immunoreactive cells were observed. The
presence of the VDR in the CNS was confirmed by in situ hybridization and RNA
based polymerase chain reaction methods with di-deoxy sequencing of the resultant
DNA product. These results support the hypothesis that 1, 25-dihydroxyvitamin D3,
through interactions with the VDR, may play a role in the development of the CNS.
PMID- 9757036
TI - Temperature-dependent effect of zolpidem on the GABAA receptor-mediated response
at recombinant human GABAA receptor subtypes.
AB - The effects of zolpidem on the two forms of recombinant human GABAA receptors
(alpha1beta2gamma2s and alpha3beta2gamma2s) at different temperatures were
functionally investigated, using the whole-cell patch recording configuration. In
both forms, zolpidem potentiated the response to GABA in a concentration
dependent manner. At 16 degrees C, the apparent dissociation constant (KD) values
for the alpha1beta2gamma2s and alpha3beta2gamma2s forms were 3.7 x 10(-8) and 5.6
x 10(-7) M, respectively. When the temperature was increased to 36 degrees C, the
KD values for the alpha1beta2gamma2s and alpha3beta2gamma2s forms were 2.1 x 10(
7) and 1.5 x 10(-6) M, respectively. Although the affinity ratio was reduced from
15.1 to 7.1-fold the selectivity of zolpidem for the alpha1beta2gamma2s still
remained at 36 degrees C.
PMID- 9757037
TI - Prostaglandin E2 increases proenkephalin mRNA level in rat astrocyte-enriched
culture.
AB - The effect of prostaglandin E2 (PGE2) on proenkephalin (proENK) mRNA expression
in primary cultured rat astrocytes was studied. The proENK mRNA level was
significantly increased about 3.3-fold 4 h after PGE2 (10 microM) treatment and
this increase was potentiated by the pre-treatment with cycloheximide (CHX; 15
microM) about 1.7-fold as much as PGE2 alone treated cells. The pretreatment with
staurosporine (1 microM) completely inhibited the increase of PGE2-induced proENK
mRNA level, although only a partial inhibition of PGE2-induced proENK mRNA level
(approximately 1.5-fold) by H89 (10 microM) was observed. The increase of PGE2
induced proENK mRNA level was not affected by the pretreatment with PD98059 (1,
5, and 10 microM), omega-conotoxin GIVA (1 microM), nimodipine (1 microM),
calmidazolium (1 microM), or KN-62 (1 microM). In addition to the proENK mRNA
level, PGE2 also increased c-Fos (approximately 4.3-fold), Fra-1 ( approximately
3.8 fold), and Fra-2 (approximately 8.2-fold) protein levels at 4 h after drug
treatment. However, c-Jun, JunB, and JunD protein levels were not affected by
PGE2. Indeed, PGE2 failed to up-regulate c-jun mRNA expression as well as its
protein product. Surprisingly, although three Jun proteins were not induced by
PGE2, AP-1 and ENKCRE-2 DNA binding activities were increased by PGE2,
(approximately 5 and approximately 2.8-fold, respectively) and which were
effectively reduced by CHX (approximately 2.5 and 2-fold, respectively). In
western blot analyses, PGE2 enhanced the phosphorylation of CREB (approximately
2.6-fold at 1 h), and CHX showed a potentiative effect on PGE2-induced CREB
phosphorylation ( approximately 1.7 fold at 1 h) which is similar to the action
on proENK mRNA regulation. Our results suggest that PGE2 increases proENK mRNA
expression via activating serine/threonine protein kinase such as PKA, but not
calcium/calmodulin dependent protein kinase and MAPK. In addition,
phosphorylation of CREB rather than the increase of AP-1 may have a possible role
at least early stage in PGE2-induced proENK mRNA level and CHX-evoked
potentiation.
PMID- 9757038
TI - Calcitonin gene-related peptide as a GH secretagogue in human and rat pituitary
somatotrophs.
AB - To elucidate the role of calcitonin gene-related peptide (CGRP) in regulating
pituitary function, we investigated the effects of CGRP and the related peptide
adrenomedullin (AdM) on the secretion of growth hormone (GH) in vitro from human
pituitary adenoma cells, rat pituitary tumor (GH3) cells, and normal rat
pituitary cells. In 3 of 5 human somatotroph adenomas, GH secretion was
stimulated by CGRP (1-100 nM). In one case of somatotroph adenoma, GH release was
observed following the addition of 10 nM GHRH and 10 nM CGRP. The addition of
CGRP or AdM (1 pM-10 nM) evoked GH secretion from GH3 cells with a bell-shaped
distribution curve. CGRP (100 pM) caused the maximum increase of GH secretion
(172+/-14 (mean+/-S.D.)% of control). The addition of CGRP8-37, an antagonist of
CGRP type 1 receptors, inhibited the stimulatory effect of AdM but did not
inhibit the effect of CGRP. The addition of CGRP and AdM evoked moderate GH
secretion from normal rat pituitary cells. These results suggested that CGRP is a
new GH secretagogue in human and rat pituitary tumor cells.
PMID- 9757039
TI - Attenuation of the lordosis-inhibiting effects of 8-OH-DPAT by TFMPP and
quipazine.
AB - Regularly cycling, proestrous female rats received infusions of 200 ng of the
serotonin (5-HT) 1A receptor agonist, (+/-) 8-hydroxy 2-(di-n-propylamino)
tetralin-HBr (8-OH-DPAT), or 200 ng 8-OH-DPAT and 1000 or 2000 ng of N-(3
trifluoro-methylphenyl) piperazine hydrochloride (TFMPP) or 2-(1-piperazinyl)
quinoline dimaleate (quipazine). Infusions were made bilaterally into the
ventromedial nucleus of the hypothalamus (VMN). Animals receiving 200 ng 8-OH
DPAT exhibited a decline in lordosis behavior following infusion. Rats receiving
8-OH-DPAT and 1000 or 2000 ng quipazine or TFMPP were protected from the lordosis
inhibiting effects of 8-OH-DPAT, alone. Although both quipazine and TFMPP act on
multiple 5-HT receptors, they overlap in their agonist action at 5-HT2 receptors.
Consequently, these results provide further evidence supporting the contention
that within the VMN, both 5-HT1A and 5-HT2 receptor subtypes contribute to the
modulation of lordosis behavior in the female rat. The data are discussed in
terms of the relative potency of 5-HT at 5-HT receptors mediating inhibition and
facilitation of lordosis behavior.
PMID- 9757040
TI - Biphasic modulatory action of the selective sigma receptor ligand SR 31742A on N
methyl-D-aspartate-induced neuronal responses in the frontal cortex.
AB - The technique of intracellular recording was used to assess the effect of SR
31742A, a selective sigma receptor ligand, on N-methyl-d-aspartate (NMDA) and (+/
)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor
mediated responses in pyramidal cells of the rat medial prefrontal cortex in
vitro brain slice preparations. Bath application of SR 31742A produced a biphasic
effect on NMDA responses: SR 31742A facilitated and inhibited NMDA-induced inward
current at low (0.01, 0.05 and 0.1 microM) and higher (0.5, 1 and 10 microM)
concentrations, respectively. The potentiating effect reached the peak (366%) at
0.1 microM, with an estimated EC50 value of 23 nM. Correspondingly, SR 31742A
also produced a similar biphasic modulatory action on excitatory postsynaptic
potentials or currents (EPSPs/EPSCs) evoked by electrical stimulation of the
forceps minor. In contrast, SR 31742A produced a modest potentiation of AMPA
responses at the concentrations from 0.01 to 1 microM. The potentiating action of
SR 31742A on NMDA-receptor mediated neurotransmission may account for, at least
partially, its antipsychotic and cognitive-enhancing potential, whereas the
inhibitory action on NMDA responses at higher concentrations may be related to
the purported neuroprotective action of sigma receptor ligands.
PMID- 9757041
TI - Behavioral changes and expression of heat shock protein hsp-70 mRNA, brain
derived neurotrophic factor mRNA, and cyclooxygenase-2 mRNA in rat brain
following seizures induced by systemic administration of kainic acid.
AB - Kainic acid-induced seizures in rats represent an established animal model for
human temporal lobe epilepsy. However, it is well-known that behavioral responses
to the systemic administration of kainic acid are inconsistent between animals.
In this study, we examined the relationship between expression of genes,
neuropathological damage, and behavioral changes (seizure intensity and body
temperature) in rats after systemic administration of kainic acid. The
considerable differences in the response to kainic acid-induced seizures were
observed in rats after a single administration of kainic acid (12 mg/kg i.p.).
There was no detection of the expression of heat shock protein hsp-70 mRNA and
HSP-70 protein in brain of vehicle-treated controls and in animals exhibiting
weak behavioral changes (stage 1-2). A moderate expression of hsp-70 mRNA was
detected throughout all regions (the pyramidal cell layers of CA1-3 and dentate
gyrus) of the hippocampus, the basolateral, lateral, central and medial amygdala,
the piriform cortex, and the central medial thalamic nucleus of rats that
developed moderate seizures (stage 3-4). Marked expression of hsp-70 mRNA was
detected in the all regions (cingulate, parietal, somatosensory, insular,
entorhinal, piriform cortices) of cerebral cortex and all regions of hippocampus,
and the central medial thalamic nucleus of the rats that developed severe
seizures (stage 4-5). In addition, marked HSP-70 immunoreactivity was detected in
the pyramidal cell layers of CA1 and CA3 regions of hippocampus, all regions
(cingulate, parietal, somatosensory, insular, piriform cortices) of cerebral
cortex, and the striatum of rats that developed severe seizures (stage 4-5).
Furthermore, a marked expression of cyclooxygenase-2 (COX-2) mRNA and brain
derived neurotrophic factor (BDNF) mRNA levels by kainic acid-induced behavioral
seizures (stage 3-4 or stage 4-5) was detected in all hippocampal pyramidal cell
layers, granule layers of dentate gyrus, piriform cortex, neocortex, and
amygdala. The present study suggest that the behavioral changes (seizure
intensity and body temperature) and neuropathological damage after systemic
administration of kainic acid are inconsistent between animals, and that these
behavioral changes (severity of kainic acid-induced limbic seizures) might be
correlated with gene expression of hsp-70 mRNA, COX-2 mRNA, and BDNF mRNA in rat
brain.
PMID- 9757042
TI - Effects of various N-terminal fragments of glucagon-like peptide-1(7-36) on food
intake in the neonatal chick.
AB - Recently, the suppressive effect on food intake by the central administration of
glucagon-like peptide-1 (GLP-1) has been confirmed in both rats and chicks. The
importance of the N-terminal amino acid, histidine, for the bioactivity of GLP
1(7-36) in the central nervous system was suggested, though the role for C
terminal amino acids in the central nervous system has not been reported. The
present study was done to elucidate the central effect of N-terminal fragments of
GLP-1(7-36) on food intake of the neonatal chick. Intracerebroventricular
(i.c.v.) administration of mammalian GLP-1(7-36) inhibited food intake of chicks,
but the fragments of GLP-1(7-16) and GLP-1(7-26) did not show the suppressive
effect on food intake. Furthermore, the extended fragments, GLP-1(7-30) and GLP
1(7-33), also had no effects on food intake. It is concluded that C-terminal
amino acids of GLP-1(7-36) have an important role for the bioactivity in the
central nervous system with special reference to feeding behavior.
PMID- 9757043
TI - Isolation of mouse vomeronasal receptor genes and their co-localization with
specific G-protein messenger RNAs.
AB - Four mouse vomeronasal receptors (mV1Rs) have been isolated by similarity to rat
vomeronasal receptor (V1R) motifs. The four mV1Rs identified in this study are
members of two distinct subfamilies. Specific in situ hybridization probes (ISH)
derived from the 3' non-coding regions of the mV1R genes, were used to detect
expression of a single receptor and probes from the homologous coding regions
were used to detect expression of subfamily members. The ISH results showed that
the mV1Rs expressing neurons were scattered in the middle/upper layer of the
vomeronasal organ (VNO) sensory epithelium in serial VNO sections but were
excluded from the deeper layers of the VNO sensory epithelium and these neurons
were found to co-express the mRNA for the G-protein Galphai2, and were distinct
from the deeper layers of the VNO sensory epithelium where the mRNA for Galphao
positive neurons was located.
PMID- 9757045
TI - Segmental effect of NMDA block in the dorsal horn on the pressor reflex.
AB - The purpose of this study was to examine the influence of NMDA receptor blockade
in the dorsal horn of adjacent spinal segments as it pertains to the pressor
reflex evoked by static contraction and stretch of skeletal muscle. In this
preparation, cats were anesthetized and the afferent fibers mediating the pressor
reflex entered the spinal cord via the L7 dorsal root. Blockade of dorsal horn
NMDA receptors at L6 and L7 attenuated the pressor reflex evoked by static
contraction and muscle stretch. However, NMDA block in the L6 dorsal horn alone
failed to alter the peak increase in MAP produced by static contraction and
muscle stretch, but the initial pressor response evoked by static contraction was
attenuated. These data support the hypothesis that the pressor reflex is
partially mediated by activation of NMDA receptors in the dorsal horn, and this
occurs at multiple spinal segments. Further, these data suggest that activation
of NMDA receptors plays an important role in initiating the rise in arterial
pressure produced by static contraction of skeletal muscle.
PMID- 9757044
TI - Calretinin-like immunoreactivity in the regenerating periodontal ruffini endings
of the rat incisor following injury to the inferior alveolar nerve.
AB - Regeneration of calretinin (CR)-like immunoreactive (IR) nerve fibers was
investigated in the periodontal ligament of the rat lower incisor following
resection of the inferior alveolar nerve (IAN). In addition, the degeneration and
regeneration processes of periodontal nerve fibers were examined by
immunohistochemistry for protein gene product 9.5 (PGP 9.5), a general neuronal
marker. In normal animals, the periodontal nerve fibers showing PGP 9.5-like
immunoreactivity (LI) formed either periodontal Ruffini endings with expanded
arborization and thin free nerve endings in the alveolar half of the ligament.
Thick CR-IR nerve fibers also appeared in a dendritic fashion in the same region,
but thin CR-IR nerve fibers were rarely observed. Five days following resection
of the IAN, a major population of PGP 9.5-IR and all CR-IR nerve fibers
disappeared except for some thin PGP 9.5-IR nerves in the periodontal ligament.
Regenerated PGP 9.5-IR nerve fibers appeared around 7 days following resection,
in contrast to a very small number of regenerated CR-IR nerve fibers. Around 14
21 days following resection, the number and terminal morphology of regenerated
PGP 9.5-IR nerve fibers were comparable to those observed in normal animals, but
the number of regenerated CR-IR nerve fibers was still smaller than that of
normal animals. The number of regenerated CR-IR nerve fibers increased to return
to normal by 56 days following injury. The delay of expression of CR-LI in the
regenerated periodontal Ruffini endings suggests that functional recovery of
periodontal Ruffini endings occurred after the completion of the regeneration of
periodontal nerve fibers.
PMID- 9757046
TI - Extracellular dopamine and catabolites in rat striatum during lactic acid
perfusion as determined by in vivo microdialysis.
AB - Many experimental studies concerning hypoxia or ischemia have reported a decrease
in intra/extracellular pH and massive dopamine (DA) release in the striatum. The
present work investigated whether the increase in striatal extracellular DA is
related to acidification or to lactate production. Striatal perfusion of lactic
acid (pH 5.5) by microdialysis in conscious freely-moving rats induced an
increase in extracellular concentrations of DA and catabolites, homovanillic acid
(HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC), as a probable result of
acidification. Perfusion with sodium lactate (pH 7.4) failed to modify DA and
catabolite release, whereas orthophosphoric acid produced the same effect as
lactic acid. As lactic acidosis is known to induce a displacement of iron from
its uptake sites, the possible role of this metal in response to acidosis was
studied by perfusing ferrozine, an iron complexing agent, at the same time as
lactic acid. The results showed that ferrous ions are involved in the process and
suggested that oxygen free radicals play a role in the extracellular release of
DA. Thus, lactic acid perfusion in rat striatum would appear to be a useful model
for in vivo studies of the mechanisms responsible for increases in extracellular
DA during hypoxia and ischemia.
PMID- 9757047
TI - Receptors and effects of the inhibitory neuropeptide somatostatin in microglial
cells.
AB - The expression of receptors for the neuropeptide somatostatin was investigated in
cultured immunocytochemically pure rat microglial cells. By the reverse
transcriptase-polymerase chain reaction, the mRNAs for the receptor subtypes
sst2, sst3 and sst4, but not sst1 and sst5 could be detected. To show that these
receptors were functionally active, the effects of somatostatin and the
metabolically stable, receptor subtype (2, 3 and 5) selective derivative
octreotide (SMS 201-995, Sandostatin) on protein phosphorylation and
proliferation were evaluated. Somatostatin induced the tyrosine phosphorylation
of a 95 kDa protein in microglia. Furthermore, somatostatin or octreotide
inhibited the basal as well as the GM-CSF-(granulocyte macrophage colony
stimulating factor) or the IL-3-(interleukin-3)-stimulated proliferation of
microglial cells. This effect was dose-dependent, with a half maximum activity of
about 0.2-0.3 nM. Somatostatin was relatively stable in the cultures due to
protease inhibitors in the serum. The results indicate that microglial cells are
targets for the widespread neuropeptide somatostatin and that its receptors can
transduce complex signals to microglia.
PMID- 9757048
TI - Orphanin FQ stimulates prolactin and growth hormone release in male and female
rats.
AB - Intracerebroventricular administration of Orphanin FQ (5.5, 55 or 550 pmol)
caused a dose-related increase in prolactin secretion in both male and female
rats and stimulated GH secretion in males. The magnitude of the prolactin
secretory response was greater in females than in males. These effects of OFQ on
prolactin and growth hormone release are the same as the stimulatory effects of
the endogenous opioid peptides.
PMID- 9757049
TI - Amphetamine administration improves neurochemical outcome of lateral fluid
percussion brain injury in the rat.
AB - This study examined the effects of the administration of D-amphetamine on the
regional accumulation of lactate and free fatty acids (FFAs) after lateral fluid
percussion (FP) brain injury in the rat. Rats were subjected to either FP brain
injury of moderate severity (1.9 to 2.0 atm) or sham operation. At 5 min after
injury, rats were treated with either d-amphetamine (4 mg/kg, i.p.) or saline. At
30 min and 60 min after brain injury, brains were frozen in situ, and cortices
and hippocampi were excised at 0 degrees C. In the saline-treated brain injured
rats, levels of lactate were increased in the ipsilateral left cortex and
hippocampus at 30 min and 60 min after injury. These increases were attenuated by
the administration of D-amphetamine at 5 min after lateral FP brain injury. At 30
and 60 min after FP brain injury, increases in the levels of all individual FFAs
(palmitic, stearic, oleic and arachidonic acids) and of total FFAs were also
observed in the ipsilateral cortex of the saline-treated injured rats. These
increases in the ipsilateral cortex and hippocampus were also attenuated by the
administration of d-amphetamine. Neither levels of lactate nor levels of FFAs
were increased in the contralateral cortex in the saline-treated injured rats at
30 min or 60 min after FP brain injury. The levels of lactate and FFAs in the
contralateral cortex were also unaffected by the administration of D-amphetamine.
These results suggest that the attenuation of increases in the levels of lactate
and FFAs in the ipsilateral cortex and hippocampus may be involved in the
amphetamine-induced improvement in behavioral outcome after lateral FP brain
injury.
PMID- 9757050
TI - Molecular cloning and pharmacological characterization of an atypical gerbil
angiotensin II type-1 receptor and its mRNA expression in brain and peripheral
tissues.
AB - In the gerbil brain, most of the [125I]Sarcosine1-Angiotensin II binding sites
are atypical, not sensitive to displacement with selective Angiotensin II AT1 and
AT2 receptor ligands. A similar atypical binding profile exists in the gerbil
kidney, where binding is highly expressed. We isolated a 2197 base pair clone
from a gerbil kidney cDNA library which encodes a 359 amino acid protein with
higher than 90% homology to other mammalian angiotensin II AT1 receptors. When
expressed in COS-7 cells, stimulation by Angiotensin II of both the cloned gerbil
receptor or the human AT1 receptor enhanced IP3 production to a similar degree.
In COS-7 cells, the gerbil receptor also had a ligand affinity profile similar to
that of the human AT1 receptor, but showed greatly reduced affinity for losartan
(IC50=3480+/-174 nM). In the gerbil brain, in situ hybridization revealed
receptor mRNA in circumventricular organs, selective hypothalamic, midbrain and
brain stem areas, and in the hippocampus, where high mRNA expression was detected
in the stratum pyramidale of the CA1 and CA2 subfields, and in the stratum
granulosum of the dentate gyrus. The expression pattern of receptor mRNA
corresponded well with that of atypical [125I]Sar1-Ang II binding. In situ
hybridization and Southern blot experiments using riboprobes against the open
reading frame and the 3'-untranslated region of the cloned gerbil Ang II receptor
cDNA suggest that gerbils have, like other rodents, two AT1 receptor subtypes.
The receptor mRNA distribution of the cloned gerbil Ang II receptor corresponds
to the distribution of AT1A receptors described in other rodent species.
PMID- 9757051
TI - Catecholamine concentrations in rat nasal mucus are modulated by trigeminal
stimulation of the nasal cavity.
AB - Olfactory mucus provides the perireceptor environment in which the initial steps
of olfactory signal transduction occur [5]. Extrinsic autonomic and trigeminal
innervation controls mucus secretion and may release neurotransmitters into nasal
mucus [13]. We quantitated catecholamines in rat nasal mucus and found that
catecholamine levels first increased and then declined with trigeminal
stimulation. These data indicate that catecholamine levels are regulated in nasal
mucus and could modulate the odor sensitivity of olfactory sensory neurons.
PMID- 9757053
TI - Electrophysiological and neuropharmacological study of tectoreticular pathways in
lampreys.
AB - Tectoreticular (TR) cells along the diencephalic-mesencephalic border are the
origin of prominent crossed and uncrossed pathways that project to the middle
(MRRN) and posterior (PRRN) rhombencephalic reticular nuclei in juvenile and
adult lampreys [I.C. Zompa, R. Dubuc, Diencephalic and mesencephalic projections
to rhombencephalic reticular nuclei in lampreys, Brain Res. (1998) in press.].
This study investigated the synaptic contacts between TR axons and the reticular
cells. Intracellular recordings were carried out in reticular neurones (n=124)
while microstimulating the TR regions. Tectoreticular inputs were recorded in all
reticular cells studied (248 PSPs); although stronger responses were evoked in
the MRRN neurones. The majority of responses were excitatory, but increasingly
mixed and inhibitory when recorded in the middle and caudal part of the reticular
nuclei. The excitation had the shortest onset latencies and sharpest slopes
measured in both reticular nuclei, while the inhibition was longer and smoother.
The characteristics of TR inputs to different reticular cell types is also
presented. The transmission of evoked responses was isolated to the crossed and
uncrossed TR pathways by studying the effects of 1% Xylocaine ejections and
surgical lesions. The TR inputs were transmitted to reticular cells through
monosynaptic and polysynaptic contacts. The synaptic transmission involved
excitatory amino acids, acting through AMPA and NMDA receptors, while the
inhibition was glycinergic. Comparisons with other sensory systems in lampreys
are discussed.
PMID- 9757052
TI - Nitric oxide as a putative messenger molecule in the crayfish olfactory midbrain.
AB - NADPH-d histochemistry was used to investigate presumptive nitric oxide synthase
(NOS)-containing neurons in the crayfish olfactory midbrain. Three anatomically
different types of local olfactory interneurons exhibiting NADPH-d activity were
observed: two pairs of large interneurons as well as positively stained globuli
cells. Branches derived from the large interneurons were confined to the
ipsilateral olfactory lobe and accessory lobe, but only a few branches innervated
the olfactory lobe glomeruli. Local field potential recordings on the olfactory
lobe showed that administration of SNP or SIN-1 (10-4 M) into the brain had
reversible inhibitory effects on electrically-evoked responses of unidentified
neuronal cell populations.
PMID- 9757054
TI - The 5-HT1A agonist 8-OH-DPAT increases the number of spike-wave discharges in a
genetic rat model of absence epilepsy.
AB - The effects of the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)
tetralin (8-OH-DPAT) on the epileptiform activity has been investigated in adult
WAG/RIJ rats. Either intraperitoneal (0.1-0.5 mg/kg) or intracerebroventricular
(2-20 microg/rat) administration of 8-OH-DPAT caused marked, dose-dependent
increases in the number and mean cumulative duration of spike-wave discharges.
These effects were attenuated by NAN-190, a 5-HT1A receptor antagonist. These
data indicate that serotonergic system regulates the epileptiform activity in
this genetic model of human absence epilepsy.
PMID- 9757055
TI - Substance P- and CGRP-immunoreactive fibers in the chicken carotid bodies after
nodose ganglionectomy and midcervical vagotomy.
AB - The chicken carotid body is richly innervated by branches from the vagus nerve
immunostained with the monoclonal antibody TuJ1 to neuron-specific class III beta
tubulin. Furthermore, peptidergic nerve fibers are densely distributed in and
around the carotid body. After transection of the vagus nerve proximal to the
nodose ganglion, TuJ1-immunoreactive fibers did not change in density but
substance P- and CGRP-immunoreactive fibers were conspicuously decreased in and
around the carotid body. After removal of the nodose ganglion, TuJ1
immunoreactive fibers markedly diminished and substance P- and CGRP
immunoreactive fibers almost disappeared. These results indicate that the vast
majority of substance P- and CGRP-immunoreactive fibers in the chicken carotid
body originate from the vagal ganglia.
PMID- 9757056
TI - Regulation of the preprosomatostatin gene by cyclic-AMP in cerebrocortical
neurons.
AB - The gene coding for preprosomatostatin (ppSom), the molecular precursor of
somatostatin (Som), is regulated at the level of transcription by calcium ions
and cyclic-AMP [F. Baldino, S. Fitzpatrick-McElligott, T. O'Kane, I. Gozes,
Hormonal regulation of somatostatin, Synapse 2 (1988) 317-325; M.R. Montminy,
M.J. Low, L. Tapia-Arancibia, Cyclic AMP regulates somatostatin mRNA accumulation
in primary diencephalic cultures and in transfected fibroblast cells, J.
Neurosci. 6 (1986) 1171-1176.], or by agents which increase intracellular levels
of cAMP directly, such as forskolin [M.R. Montminy, M.J. Low, L. Tapia-Arancibia,
Cyclic AMP regulates somatostatin mRNA accumulation in primary diencephalic
cultures and in transfected fibroblast cells, J. Neurosci. 6 (1986) 1171-1176.].
Transcriptional induction of the ppSom gene as examined in PC12 cells,
transfected fibroblasts and primary diencephalic cultures, requires the highly
conserved cAMP response element (CRE), which confers gene responsiveness to cAMP
[M. Comb, N. Mermod, S.E. Hyman, Proteins bound at adjacent DNA elements act
synergistically to regulate human proenkephalin cAMP inducible transcription,
EMBO J. 7 (1988) 3793-3805; T. Tsukada, J.S. Fink, G. Mandel, Identification of a
region in the human vasoactive intestinal polypeptide gene responsible for
regulation by cyclic AMP, J. Biol. Chem. 262 (1987) 8743-8747.]. The ppSom gene
is subject to stringent regulation during cerebrocortical development in vivo;
however, little information is available regarding ppSom gene regulation by
neurotransmitters or second-messengers in cortical neurons. We used primary
cerebrocortical cell cultures from fetal mice to examine the dose-response and
time-course of ppSom gene expression in response to the cyclic-AMP analogs,
dibutyrl-cAMP (dbcAMP), and 8-bromo-cAMP (8-BrcAMP). We report a dose-response
for both analogs in the range of 0.1-10 mM. Dose-response studies using agents
which directly stimulate intracellular cAMP synthesis (forskolin) or inhibit its
breakdown (3-isobutyl 1-methyl xanthine) were also performed. We observed an
apparent synergistic effect on ppSom expression when used in combination. An
increase in ppSom mRNA levels was observed by 4 h, with a maximal response at 12
24 h. No change in ppSom mRNA levels was observed in response to phorbol
myristate acetate (PMA). Our findings confirm the specificity of ppSom gene
regulation by cAMP and Ca2+ ions, and demonstrate the utility of using primary
cerebrocortical cultures for the study of somatostatin gene expression by
neurotransmitters and second-messengers as a model of human neurologic disorders.
PMID- 9757057
TI - GABAB receptor stimulation phase-shifts the mammalian circadian clock in vitro.
AB - The mammalian circadian clock in the suprachiasmatic nucleus (SCN) generates 24-h
rhythms in vitro. Here we show that the GABAB agonist baclofen resets the SCN
pacemaker in vitro in a phase-dependent manner: advances were induced at
zeitgeber time (ZT) 6, and delays were induced at ZT 22. Both effects were
blocked the GABAB antagonist, 2-hydroxysaclofen, while the GABAA antagonist,
bicuculline was ineffective. Thus, the SCN pacemaker is sensitive to resetting by
GABAB stimulation.
PMID- 9757058
TI - A role of climbing fibers in regulation of flocculonodular lobe protein kinase C
expression during vestibular compensation.
AB - The behavioral recovery from unilateral labyrinthectomy (UL) in rats is
accompanied by asymmetric expression of Protein kinase C (PKC) in parasagittal
regions of the flocculonodular lobe within 6 h after UL, which resolves to the
control, symmetric pattern within 24 h. These changes consist of a regionally
selective increase in the number of PKC-immunopositive Purkinje cells
contralateral to the lesion. This study tested the hypotheses (1) that climbing
fiber innervation inhibits PKC expression and (2) that climbing fibers are
essential for the observed changes in PKC expression within 6 h after UL. The
patterns of flocculonodular lobe Purkinje cell PKCdelta expression were analyzed
6 h post-operatively in both UL and sham-operated that had been treated
previously with 3-acetylpyridine to destroy the inferior olive. These data were
compared with previous results from rats with an intact olive. The results
suggest that at least two signals regulate the zonal distribution of Purkinje
cell PKCdelta expression in the flocculonodular lobe during the early period of
compensation from UL. Climbing fiber activation appears to reduce PKC expression,
while extraolivary mechanisms appear to up-regulate PKC expression. It is
suggested that the climbing fiber signals may act as a molecular 'filter' or
'automatic gain control' which adjusts the contributions of these kinases to
synaptic plasticity within the context of the background activity of climbing
fibers.
PMID- 9757059
TI - Volatile anesthetics directly activate baseline S K+ channels in aplysia neurons.
AB - The actions of halothane on serotonin-sensitive potassium channels (S K+
channels) were studied in sensory neurons of Aplysia. The normalized open
probability of S K+ channels was increased by clinical concentrations of
halothane in cell-attached and excised patches from neurons of the pleural
ventrocaudal cluster. No voltage-dependence of channel activation by halothane
was observed. Pre-treatment of neurons with 8-bromo-cAMP (8-Br-cAMP) or
nordihydroguaiaretic acid (NDGA) had no effect on the relative level of channel
activation by halothane. S K+ channels that were activated by arachidonic acid
could also be activated by halothane and exhibited closely similar amplitude
distributions of open channel current. Results from these experiments showed that
S K+ channel activation by halothane did not depend on second messenger
modulation of channel activity. We conclude that it is likely that halothane
directly activates S K+ channels.
PMID- 9757060
TI - The expression of voltage-dependent calcium channel beta subunits in human
hippocampus.
AB - The beta subunits of voltage-dependent calcium channels (VDCC) modulate the
electrophysiology and cell surface expression of pore-forming alpha1 subunits. In
the present study we have investigated the distribution of beta1,beta2,beta3 and
beta4 in the human hippocampus using in situ hybridization (ISH) and
immunohistochemistry. ISH studies showed a similar distribution of expression of
beta1,beta2 and beta3 subunit mRNAs, including labelling of the dentate granule
cell layer, all CA pyramidal regions, and the subiculum. Relatively low levels of
expression of beta1 and beta2 subunit mRNAs correlated with low protein
expression in the immunocytochemical (ICC) studies. There was a relative lack of
beta4 expression by both ISH and ICC in the CA1 region, compared with high levels
of expression in the subiculum. Immunostaining for beta1 and beta2 subunits was
weak and relatively homogeneous throughout the hippocampus. The beta3 and beta4
subunits appeared to be more discretely localized. In general, beta3
immunoreactivity was moderate both in cell bodies, and as diffuse staining in the
surrounding neuropil. Strongest staining was observed in mossy fibres and their
terminal region in the CA3 stratum lucidum. In contrast, beta4-immunoreactivity
in the neuropil showed intense dendritic localisation. Unlike the other subunits,
beta4-immunoreactivity was absent from CA1 pyramidal neurones but was present in
a small population of interneurone-like cells. The localisation of beta3 and
beta4 may represent presynaptic and postsynaptic compartments in some populations
of hippocampal neurones. Comparison of beta subunit distribution with previously
published data on alpha1 subunits indicates certain neuronal groups and
subcellular compartments in which the subunit composition of native pre- and
postsynaptic VDCC can be predicted.
PMID- 9757061
TI - Effects of ethanol on rat somatosensory cortical neurons.
AB - In this study, we characterized the local effects of ethanol (EtOH) on
postsynaptic potentials (PSPs) and membrane properties of layer II-III (L2-3) and
layer V (L5) somatosensory cortical neurons. Intracellular recordings were done
using the in vitro slice preparation of rat somatosensory cortex. Our results
show that EtOH exerts local effects on cortical cell membrane at physiologically
relevant concentrations. A predominant effect of EtOH was to reduce excitability
of L2-3 and L5 neurons by increasing the rheobase, decreasing input resistance
and repetitive firing, reducing PSPs amplitude and the probability of evoking
action potentials. Early (6 ms) and late (18 ms) PSP components were affected
differentially by EtOH, the late components being more suppressed. Overall, EtOH
mediated suppression of PSPs was stronger in L5 neurons. Cortical neurons were
divided into three subtypes: regular spiking adapting (RS-A), regular spiking non
adapting (RS-NA) and bursting (D-IB) neurons. PSPs evoked in RS-A neurons were
more sensitive to EtOH suppressant effects. EtOH effects on input resistance were
distributed differentially among the three groups of neurons. These results
support the notion that EtOH disrupts higher processing of somatosensory
information via a differential alteration of cortical neuron's membrane
properties and synaptic transmission.
PMID- 9757062
TI - Glutamate-induced cytotoxicity in PC12 pheochromocytoma cells: role of oxidation
of phospholipids, glutathione and protein sulfhydryls revealed by bcl-2
transfection.
AB - Incubation of mock-transfected PC12 rat pheochromocytoma cells (PC12) for 2 h
with increasing concentrations of glutamate caused progressive loss of viability
(e.g., 67% with 15 mM glutamate). In contrast, the viability of bcl-2-transfected
cells (PC12/bcl-2) was unaffected by glutamate. Neither PC12 nor PC12/bcl-2 cells
showed a significant incidence of apoptosis in response to glutamate.
Conventional phospholipid analysis by high-performance TLC and phosphorous
determination showed no significant changes in the phospholipid composition of
either cell line incubated with =15 mM glutamate. Phospholipid peroxidation was
quantified in the cells using our newly developed method based on fluorescence
HPLC analysis of metabolically incorporated oxidation-sensitive and fluorescent
fatty acid, cis-parinaric acid. Unlike previous studies that measured total
phospholipid oxidation, this novel technology permitted quantitation of oxidative
stress in different classes of labeled phospholipids (the amount of labeled
phospholipids in the cells did not exceed 1% of total phospholipids). Significant
peroxidation of phosphatidylcholine and phosphatidylethanolamine occurred in PC12
cells treated with >5 mM glutamate. The peroxyl radical initiator 2,2'-azobis(2,4
dimethylvaleronitrile) caused a pronounced loss of all major phospholipid classes
in PC12 cells, but no loss of cell viability. No phospholipid peroxidation was
detected in PC12/bcl-2 cells incubated with =15 mM glutamate or with 2, 2'
azobis(2,4-dimethylvaleronitrile). These results directly demonstrate that
peroxidation of membrane phospholipids is not responsible for the cytotoxicity of
glutamate in PC12 cells. Total cellular thiol, protein thiol and GSH reserves
were quantified by a previously described electron paramagnetic resonance
spectrometric method. Total thiols were ca. 1.5-fold greater in PC12/bcl-2 than
in PC12 cells. Glutamate (=5 mM) caused a progressive and equally significant
decrease in total thiols and GSH in both PC12 and PC12/bcl-2 cells. High
glutamate concentrations caused oxidation of protein sulfhydryls in PC12 cells,
but not in PC12/bcl-2 cells. The results suggest that the changes in cellular
milieu caused by bcl-2 gene transfection protect PC12 cells from the toxic
effects of glutamate in a manner consistent with prevention of protein sulfhydryl
oxidation.
PMID- 9757063
TI - Glial fibrillary acidic protein (GFAP) immunoreactivity in enteric ganglia of the
chick embryo.
AB - We examined by immunohistochemistry the expression of glial fibrillary acidic
protein (GFAP) in enteric ganglia of the chick embryo, using a polyclonal
antibody. The morphology of enteric ganglion cells was examined by electron
microscopy. Faint GFAP immunoreactivity was detected in ganglion cells and cell
processes from around day 7 in ovo. Later in development the intensity of the
immunofluorescence increased and it became more evident that immunoreactive small
ganglion cells (interpreted as primitive glial cells), and their processes,
surrounded larger negative cell profiles (interpreted as primitive neuronal
cells); GFAP immunofluorescence was also evident in intramuscular and mucosal
nerve trunks. In colocalization experiments, GFAP immunoreactivity was detected
in a proportion of HNK-1/N-CAM immunoreactive ganglion cells, in both the
myenteric and submucosal plexus. In addition, we observed GFAP immunoreactive
nerves in wholemount preparations of chick gut from as early as day 4.5 in ovo.
In the ganglionated nerve of Remak, GFAP immunoreactive satellite and Schwann
cells were in evidence from day 5 of incubation. Neuronal markers, such as
neurofilament, have been detected very early in development in neural crest cell
populations in chick enteric ganglia. In contrast, the expression of markers of
the glial phenotype has previously been observed only in the late stages of
embryonic development. From our experiments, we conclude that neuronal and glial
phenotypes are immunohistochemically distinct from as early as day 4.5 of
incubation, even if by ultrastructural criteria glial cells are clearly
distinguishable from neurons only after day 16 in ovo.
PMID- 9757065
TI - Human prodynorphin gene generates several tissue-specific transcripts.
AB - The present study analyzes the transcription of the human prodynorphin gene.
Transfection experiments indicate that promoter activity for the 2.8 kb 'brain
type' human prodynorphin mRNA resides in the DNA region located 140-180 b
upstream of the exon 1/intron A boundary and not 1.2 kb further upstream, as
proposed by others [S. Horikawa, T. Takai, M. Toyosato, H. Takahashi, M. Noda, H.
Kakidani, T. Kubo, T. Hirose, S. Tanayama, H. Hayashida, T. Miyata, S. Numa,
Isolation and structural organization of the human preproenkephalin B gene,
Nature 306, 1983, pp. 611-614]. The new data locates the human prodynorphin gene
promoter for the brain-type mRNA in a position corresponding to the position of
the rat prodynorphin gene promoter [J. Douglass, C.T. McMurray, J.E. Garett, J.P.
Adelman, L. Calavetta, Characterization of the rat prodynorphin gene, Mol.
Endocrinol. 3, 1989, pp. 2070-2078]. Three previously not described types of
human prodynorphin mRNA of the same size, 2.8 kb, one expressed in fetal brain
and two others in testis, were characterized in this study. These mRNAs are
generated by alternative splicing of novel 5'-uppermost exons and transcription
is probably initiated from other promoters. Human neuroblastoma SH-SY5Y and SK-N
MC cell lines previously used in studies of gene transcription have the 2.8 kb
prodynorphin mRNA of adult brain alongside a more abundant, shorter 2.3 kb
transcript. The latter transcript was also found in testis and in fetal brain. It
lacked the 5'-part of the 2.8 kb mRNA including the signal peptide encoding
sequence. The complex pattern of prodynorphin gene expression and its functional
consequences are issues for further studies.
PMID- 9757064
TI - Decreased expression of GABAA receptor alpha6 and beta3 subunits in stargazer
mutant mice: a possible role for brain-derived neurotrophic factor in the
regulation of cerebellar GABAA receptor expression?
AB - The cerebellar granule cells of the spontaneous recessive mutant mouse strain,
stargazer (stg/stg), fail to express brain-derived neurotrophic factor mRNA. This
deficit is exclusive to these neurons and is believed to underlie the motor
irregularities displayed by stg/stg, though the molecular basis for their
phenotype has still to be resolved. Brain-derived neurotrophic factor has been
shown to play a role in the postnatal maturation of cerebellar granule cells.
Differentiation of these neurons, postnatally, is characterised by a switch in
their GABAA receptor subunit expression profile. Notably, the GABAA receptor
alpha6 subunit, which is specific to these neurons, becomes detectable at
postnatal days 10-14 (P10-14). To determine whether cerebellar GABAA receptor
expression has been compromised in stg/stg mice, the expression levels of GABAA
receptor alpha1, alpha6, beta2 and beta3 subunits were compared between stg/stg
mice and the appropriate wild-type background strain, C57BL/6J (+/+). By
quantitative immunoblotting, it was found that the expression of the alpha6 and
beta3 subunits was 23+/-8% and 38+/-12% (mean+/-S.E.M., n=6) of control (+/+)
levels, respectively. In contrast, the expression of the alpha1 and beta2
subunits was not significantly different from controls, being 116+/-11% and 87+/
24% (mean+/-S.E.M., n=6) of +/+ levels, respectively. Total specific [3H]Ro15
4513 binding activity detected in cerebellar membranes prepared from stg/stg was
not significantly different from +/+ mice. However, the benzodiazepine agonist
insensitive subtype of [3H]Ro15-4513 binding activity, a pharmacological motif of
alpha6 subunit-containing GABAA receptors, was lower in stg/stg mice relative to
the +/+ strain which correlated with the lowered level of alpha6 subunit
expression. Thus, we have identified an abnormality in the GABAA receptor profile
of stg/stg mutant mice that might underpin its irregular phenotype.
PMID- 9757066
TI - A tachykinin NK1 receptor antagonist, CP-122,721-1, attenuates kainic acid
induced seizure activity.
AB - Substance P (SP) can play an important role in neuronal survival. To analyze the
role of SP in excitotoxicity, kainic acid (KA) was administered to rats and in
situ hybridization was used to analyze the levels of the SP encoding
preprotachykinin-A (PPT-A) mRNA in striatal and hippocampal subregions 1, 4, and
24 h and 7 days after KA. In striatum and piriform cortex, PPT-A mRNA peaked 4 h
after KA while in hippocampus, levels peaked after 24 h. KA caused seizures and
neuronal toxicity as indicated by a reduction of the number of neurons in the
hippocampal CA1 subregion after 7 days. KA was later administered alone or
following pretreatment with the tachykinin NK1 receptor antagonist CP-122,721-1
(0.3 mg/kg). The pretreatment decreased seizure activity and a negative
correlation was found between seizure activity and survival of CA1 neurons.
Conclusively, treatment with CP-122,721-1 has a seizure inhibiting property and
may possibly counteract KA-induced nerve cell death in CA1.
PMID- 9757067
TI - The increase in angiotensin type-2 receptor mRNA level by glutamate stimulation
in cultured rat cortical cells.
AB - The changes in the angiotensin type-2 (AT2) receptor mRNA level during glutamate
neurotoxicity in cultured rat cortical cells are examined to assess the possible
involvement of AT2 receptor in cell injury. The day 10-14 cortical neurons were
exposed to glutamate at a toxic concentration of 100 microM for 15 min. The
viability of the culture was reduced by 60% after 24 h. AT2 receptor mRNA was
then increased 2-fold after exposure to glutamate, while the maximum increase was
observed in a dose-dependent manner (50-1000 microM) 3 h after glutamate
stimulation. AT2 receptor binding also increased 3-12 h after glutamate exposure.
The results suggest that the increase in the AT2 receptor preceded to some extent
the insult of the cell after exposure. The increase in the mRNA level was
suppressed by MK-801, N-methyl-D-aspartate (NMDA) receptor antagonist, thus
indicating the possible involvement of NMDA receptor. The increase in the mRNA
level was also antagonized by N-nitro L-arginine methyl-ester, a nitric oxide
synthase inhibitor. The hemoglobin, a nitric oxide trap, inhibited the increase
in the mRNA level. These results suggest that the increase in the mRNA level is
associated with the nitric oxide synthesis by glutamate exposure. The viability
of cortical cells after glutamate stimulation was partially restored by the AT2
receptor antagonist and by the antisense oligonucleotide for the AT2 receptor.
The present results thus suggest that the AT2 receptor may in some way be related
to one of the processes in cell injury caused by glutamate.
PMID- 9757068
TI - Differentially expressed genes in hippocampal cell cultures in response to an
excitotoxic insult by quinolinic acid.
AB - The NMDA-type glutamate receptor agonist quinolinic acid (QA), which causes
tissue lesions in the rat brain as well as cell loss in neuronal cultures, is
widely used in models of glutamate excitotoxicity. The aim of this study was to
evaluate the alterations in gene expression in a primary hippocampal cell culture
after exposure to QA. By means of differential mRNA display, we were able to
pinpoint as many as 23 bands which appeared to be upregulated after a 6-h
treatment with quinolinic acid. The differential expression of 13 cDNAs could be
confirmed by dot blot and/or Northern analysis. Of the cDNAs, the p112 regulatory
subunit of the 26S proteasome, a PDGF-associated protein and the glia-derived
protease nexin PN-1 could be identified. The results provide emphasis to the
participation of proteolysis and protease inhibition in neurodegenerative
processes.
PMID- 9757069
TI - The inhibition of human neuronal K+ currents by general anesthetic agents is
altered by extracellular K.
AB - We demonstrate for the first time that the extracellular potassium concentration
influences the inhibition of human neuronal delayed rectifier potassium currents
by general anesthetics. This observation suggests a modulatory role for
extracellular potassium ions in the action of some general anesthetic agents.
PMID- 9757070
TI - Methamphetamine-induced increase in striatal NF-kappaB DNA-binding activity is
attenuated in superoxide dismutase transgenic mice.
AB - Methamphetamine injection (x4 with 2-h interval) caused dose-dependent activation
of striatal NF-kappaB activity. Striatal NF-kappaB binding increased
significantly at 1-3 h after the last injection of methamphetamine (10 mg/kg,
i.p. x4). This induction of striatal NF-kappaB activity was significantly
attenuated in Cu, Zn-superoxide dismutase transgenic mice in a gene dosage
dependent fashion. The present results suggest that reactive oxygen species
generated by methamphetamine injections can activate striatal NF-kappaB DNA
binding during this drug-induced toxic process.
PMID- 9757071
TI - Interleukin-1 induces c-Fos immunoreactivity in primary afferent neurons of the
vagus nerve.
AB - Peripheral administration of bacterial endotoxin, an immune stimulant, induces
evidence of activation in vagal primary afferent neurons. To determine whether
interleukin-1beta (IL-1beta) is part of the molecular pathway leading to this
activation, we assessed the expression of the neuronal activation marker c-Fos in
vagal primary afferent neurons after intraperitoneal injections of IL-1beta (2
microg/kg). IL-1beta, but not vehicle, induced c-Fos expression, demonstrating
that IL-1beta is likely an important signal from the immune system to the vagus
nerve, and thus the brain.
PMID- 9757073
TI - Effects of weaning and restraint stress on glucocorticoid receptor binding
capacity in limbic areas of domestic pigs.
AB - Changes in glucocorticoid receptor (GR) binding in different brain areas were
investigated in neonatal and adult pigs exposed to psychological stress (weaning)
and a physical stressor (repeated snaring). The GR binding was significantly
decreased 4 days after weaning in both the hippocampus and the amygdala, but
there were no changes in the hypothalamus. Repeated snaring of adult pigs
resulted in a significant diminished GR binding only in the hippocampus.
PMID- 9757074
TI - Effects of cocaethylene on dopamine and serotonin synthesis in Long-Evans and
Sprague-Dawley brains.
AB - We examined the behavioral and neurochemical effects of cocaethylene treatment in
Long-Evans (LE) and Sprague-Dawley (SD) rats. Cocaethylene-induced behaviors were
significantly less in LE rats. Cocaethylene caused an inhibition of dopamine
synthesis in the caudate nucleus and nucleus accumbens that was equivalent in
both rat lines. Serotonin synthesis was also suppressed by cocaethylene
treatment, however this phenomenon was less pronounced when compared with the
effects on dopamine synthesis.
PMID- 9757075
TI - Alterations in the density of excrescences in CA3 neurons of hippocampus in rats
subjected to self-stimulation experience.
AB - Self-stimulation (SS) rewarding experience induced alterations in the density of
excrescences in the apical dendrites of CA3 neurons were studied in adult male
Wistar rats. SS experience was provided daily for an hour over a period of 10
days, through bipolar stainless steel electrodes implanted bilaterally in lateral
hypothalamus and substantia nigra-ventral tegmental area. The results revealed a
significant (P<0.001) increase in the number of excrescences in both main shaft
and sub branches of the apical dendrites in SS experienced group compared to
control groups of rats. The increased number of excrescences in CA3 neurons might
be due to an enhancement in the synaptic transmission in the mossy fiber pathway
following SS experience.
PMID- 9757076
TI - Negative inotropic vagal preganglionic neurons in the nucleus ambiguus of the
cat: neuroanatomical comparison with negative chronotropic neurons utilizing dual
retrograde tracers.
AB - The vagal postganglionic controls of cardiac rate and left ventricular
contractility are mediated by separate intracardiac ganglia, the sino-atrial (SA)
and cranio-ventricular (CV) ganglia, respectively. We injected a different
retrograde tracer into each of these ganglia (in the same animal) and
subsequently examined the brain for the presence of single labeled or double
labeled vagal preganglionic neurons. Retrogradely labeled cells from either
ganglion were found exclusively in the ventrolateral nucleus ambiguus (NA-VL).
There was considerable overlap in the distribution of labeled cells from either
ganglion, however fewer than 3% of labeled neurons were double labeled. The data
are consistent with the hypothesis that the preganglionic controls of cardiac
rate and left ventricular contractility are mediated by largely separate but
overlapping groups of cardioinhibitory neurons originating from the NA-VL. These
neurons have parallel but morphologically independent pathways projecting to the
SA and CV ganglia. Physiological experiments are needed to support this
hypothesis.
PMID- 9757077
TI - Time course for kindling-induced changes in the hilar area of the dentate gyrus:
reactive gliosis as a potential mechanism.
AB - Recurrent seizure activity induced during kindling has been reported to cause an
increase in the hilar area of the dentate gyrus of the hippocampus. To date, very
little is known about the mechanism of this increase. This study investigated the
time course for kindling-induced changes in the hilar area of the dentate gyrus
at seven days, one month, and two months post-kindling. Hilar area of the dentate
gyrus was significantly increased by approximately 46% at seven days and remained
elevated at one month, but declined back to control levels by two months. Glial
fibrillary acidic protein (GFAP) immunostaining was also evaluated at the same
time points to determine whether kindling-induced changes in the hilar area of
the dentate gyrus are related to kindling-induced glial cell changes. Increases
in hilar GFAP immunostaining by approximately 57% were observed at seven days and
at one month post-kindling, but not at two months post-kindling. These findings
indicate that kindling-induced changes in the hilar area of the dentate gyrus and
kindling-induced glial cell changes follow a similar time course, and that
kindling-induced glial cell changes may mediate the observed changes in the hilar
area of the dentate gyrus.
PMID- 9757078
TI - Prevention of DOI-mediated wet dog shakes by inhibitors of nitric oxide synthase.
AB - The purpose of this study was to determine if (+/-)-1-(2, 5-dimethoxy-4
iodophenyl)-2-aminopropane (DOI)-induced wet dog shakes (WDS) required the
involvement of nitric oxide synthases (NOS). Systemic administration of the
general NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME), but not its d
isomer, and the neuronal NOS (nNOS) inhibitor 7-nitroindazole completely blocked
DOI-mediated WDS in a dose dependent manner. The data provides evidence that
serotonin 5HT2 receptors are coupled to nNOS activation in the rat brain.
PMID- 9757079
TI - Reaction centre photochemistry in cyanide-treated photosystem II.
AB - EPR was used to study the triplet state of chlorophyll generated by radical pair
recombination in the photosystem II (PSII) reaction centre. The spin state of the
non-haem Fe2+ was varied using the CN--binding method (Y. Sanakis, V. Petrouleas,
B.A. Diner, Biochemistry 33 (1994) 9922-9928) and the redox state of the quinone
acceptor (QA) was changed from semi-reduced to fully reduced (F.J.E. van Mieghem,
W. Nitschke, P. Mathis, A.W. Rutherford, Biochim. Biophys. Acta 977 (1989) 207
214). It was found that the triplet was not detectable using continuous wave EPR
when QA- was present irrespective of the spin-state of the Fe2+. It was also
found that the triplet state became detectable by EPR when the semiquinone was
removed (by reduction to the quinol) and that the triplet observed was not
influenced by the spin state of the Fe2+. Since it is known from earlier work
that the EPR detection of the triplet reflects a change in the triplet lifetime,
it is concluded that the redox state of the quinone determines the triplet
lifetime (at least in terms of its detectability by continuous wave EPR) and that
the magnetic state of the iron, (through the weakly exchange-coupled QA- Fe2+
complex) is not a determining factor. In addition, we looked for polarisation
transfer from the radical pair to QA- in PSII where the Fe2+ was low spin. Such
polarisation is seen in bacterial reaction centres under comparable conditions.
In PSII, however, we were unable to find evidence for such polarisation of the
semiquinone. It is suggested that both the short triplet lifetime in the presence
of QA- and the lack of polarised QA- might be explained in terms of the electron
transfer mechanism for triplet quenching involving the semiquinone which was
proposed previously (F.J.E. van Mieghem, K. Brettel, B. Hillmann, A. Kamlowski,
A.W. Rutherford, E. Schlodder, Biochemistry 34 (1995) 4798-4813). It is suggested
that this mechanism may occur in PSII (but not in purple bacterial reaction
centres) due the triplet-bearing chlorophyll being adjacent to the pheophytin at
low temperature as suggested from structural studies (F.J.E. van Mieghem, K.
Satoh, A.W. Rutherford, Biochim. Biophys. Acta 1058 (1992) 379-385).
PMID- 9757080
TI - The triplet state of the FMO complex of the green sulfur bacterium
Prosthecochloris aestuarii studied with single-crystal EPR.
AB - Triplet-electron paramagnetic resonance (EPR) spectra were obtained of single
crystals of the FMO complex of the green sulfur bacterium Prostecochloris
aestuarii. The experiments support the results presented in a previous paper
(Louwe et al., J. Phys. Chem. 101 (1997) 11280), which showed that the
experimental optical spectra of this pigment-protein complex are best reproduced
by assuming that one bacteriochlorophyll (BChl 3) is energetically isolated and
that this BChl is the triplet-carrying BChl of the FMO complex at cryogenic
temperatures for low excitation density. When comparing the experimental and
simulated data sets of the triplet-EPR spectra in single crystals, the best fit
is obtained for two triplet states, one localized at BChl 3 and the other at BChl
1. The existence of two different triplet states is traced to the relatively high
excitation power necessary to observe the small triplet-EPR signal of the FMO
single crystals.
PMID- 9757081
TI - Paracoccus denitrificans cytochrome c oxidase: a kinetic study on the two- and
four-subunit complexes.
AB - Cytochrome c oxidase from Paracoccus denitrificans has been purified in two
different forms differing in polypeptide composition. An enzyme containing
polypeptides I-IV is obtained when the purification procedure is performed in
beta-d-dodecylmaltoside. If, however, Triton X-100 is used to purify the enzyme
under otherwise identical conditions, an enzyme is obtained containing only
subunits I-II. The two enzymes are undistinguishable by optical spectroscopy but
show significant differences in the transient and steady-state time regimes, as
studied by stopped-flow spectroscopy. The observed differences, however, are not
due to removal of subunits III and IV, but rather to a specific effect of Triton
X-100 which appears to affect cytochrome c binding. From these results it is not
expected that subunits III and IV play any significant role in cytochrome c
binding and, possibly, in the subsequent electron transfer processes. The results
also suggest that both electrostatic and hydrophobic interactions may be
important in the initial electron transfer process from cytochrome c.
PMID- 9757082
TI - Triplet energy transfer in bacterial photosynthetic reaction centres.
AB - [3-vinyl]-132-OH-bacteriochlorophyll a has been selectively exchanged against
native bacteriochlorophyll a in the monomer binding sites at the A- and B-branch
of the photosynthetic reaction centre from Rhodobacter sphaeroides. Transient
absorption difference measurements were performed on these samples over a
temperature range from 4.2 to 300 K with 20 ns time resolution. Specifically the
decay of the primary donor triplet state, 3P870, as well as the rise and decay
rates of the carotenoid triplet state, 3Car (spheroidene), were measured. The
observed rates revealed a thermally activated carotenoid triplet formation
corresponding to the decay of the primary donor triplet state. The activation
energies for the triplet energy transfer process were 100(+/-10) cm-1 for
reaction centers from wild-type Rhodobacter sphaeroides 2.4.1, with and without
exchange of the monomeric bacteriochlorophyll on the electron transfer-active
branch, BA. For reaction centers from Rhodobacter sphaeroides R26.1 with both
monomers exchanged against [3-vinyl]-132-OH-bacteriochlorophyll a, and subsequent
spheroidene reconstitution the activation energy was 460(+/-20) cm-1. These
activation energies correspond to the energy difference between the triplet
states of the accessory BChl monomer, BB, and the primary donor when native BChl
a or [3-vinyl]-132-OH-BChl a is present in the BB binding site. In all samples
the 3Car formation rates were bi-phasic over a large temperature range. A fast
temperature-independent rate was observed on the wavelength of the carotenoid
triplet-triplet absorption which dominated at very low temperatures.
Additionally, a slower temperature-independent 3Car formation rate was observed
at low temperatures which could be explained with the assumption of heterogeneity
in the energy barrier (3BB) and/or the primary donor triplet state (3P870). A
tunneling mechanism as proposed earlier by Kolaczkowski (PhD thesis, Brown
University, 1989) is not only unnecessary but also incompatible with the
available experimental data.
PMID- 9757083
TI - Flash-induced changes in buffering capacity of reaction centers from
photosynthetic bacteria reveal complex interaction between quinone pockets.
AB - A novel method was applied to determine light-induced protonation in reaction
centers from photosynthetic purple bacteria. Changes in buffering capacities upon
flash excitation were detected in (0.03% Triton X-100) detergent solution of
reaction centers from Rhodobacter (Rb.) sphaeroides and Rb. capsulatus wild type
and mutant strains with empty or occupied secondary quinone (QB) binding sites in
the presence of an external electron donor. The light-induced differences in
buffering capacities between pH 4 and 11 were analyzed in terms of protonatable
residues. Due to its differential nature, this method is more sensitive to the
position and shift of pKa of the individual groups than the direct method based
on proton uptake measurements. Out of the four different ionizable residues which
were used to fit the curves, the two groups with apparent (dark) pKa values
between 8.4-8.8 and 9.5-10.0 (depending on the species and conditions)
disappeared when the native ubiquinone10 was replaced by menadione at the primary
quinone (QA) binding site of Rb. sphaeroides or when the key protonatable
residues (L212Glu and L213Asp) were replaced by non-protonatable alanines in the
QB binding site of the AA+M43D mutant from Rb. capsulatus. The experimentally
observed acidic and neutral residues remained unchanged. These results obtained
from modifications in both quinone sites reveal the origin of the alkaline pH
groups: they reflect the interaction of QA- and the cluster of ionizable residues
around L212Glu in the QB binding pocket. The involvement of two residues with
close pKa values reflects the complex titration of the cluster. The interaction
between the quinone pockets is best described qualitatively as a network of
ionizable residues extending from the QA site to the QB site.
PMID- 9757084
TI - The two spectroscopically different short wavelength protochlorophyllide forms in
pea epicotyls are both monomeric.
AB - The spectral properties of the protochlorophyllide forms in the epicotyls of dark
grown pea seedlings have been studied in a temperature range, from 10 to 293 K
with conventional fluorescence emission and excitation spectroscopy as well as by
fluorescence line narrowing (FLN) at cryogenic temperatures. The conventional
fluorescence techniques at lower temperatures revealed separate bands at 628, 634
636, 644 and 655 nm. At room temperature (293 K) the 628 and 634-636 nm emission
bands strongly overlapped and the band shape was almost independent of the
excitation wavelength. Under FLN conditions, vibronically resolved fluorescence
spectra could be measured for the 628 and 634-636 nm bands. The high resolution
of this technique excluded the excitonic nature of respective excited states and
made it possible to determine the pure electronic (0,0) range of the spectra of
the two components. Thus it was concluded that the 628 and 634-636 nm (0,0)
emission bands originate from two monomeric forms of protochlorophyllide and the
spectral difference is interpreted as a consequence of environmental effects of
the surrounding matrix. On the basis of earlier results and the data presented
here, a model is discussed in which the 636 nm form is considered as an enzyme
bound protochlorophyllide and the 628 nm form as a protochlorophyllide pool from
which the substrate is replaced when the epicotyl is illuminated with continuous
light.
PMID- 9757085
TI - Structure of 3,4-dichloroisocoumarin-inhibited factor D.
AB - Factor D (D) is a serine protease essential in the activation of the alternative
complement pathway. Only a few of the common serine protease inhibitors inhibit
D, binding covalently to the serine hydroxyl of the catalytic triad. 3,4
Dichloroisocoumarin (DCI) is a mechanism-based inhibitor which inhibits most
serine proteases and many esterases, including D. The structure of the
enzyme:inhibitor covalent adduct of D with DCI, DCI:D, to a resolution of 1.8 A
is described, which represents the first structural analysis of D with a
mechanism-based inhibitor. The side chain of the ring-opened DCI moiety of the
protein adduct undergoes chemical modification in the buffered solution,
resulting in the formation of an alpha-hydroxy acid moiety through the
nucleophilic substitution of both Cl atoms. The inhibited enzyme is similar in
overall structure to the native enzyme, as well as to a variety of isocoumarin
inhibited trypsin and porcine pancreatic elastase (PPE) structures, yet notable
differences are observed in the active site and binding mode of these small
molecule inhibitors. One region of the active site (residues 189-195) is
relatively conserved between factor D, trypsin, and elastase with respect to
amino-acid sequence and to conformation. Another region (residues 214-220)
reflects the amino-acid substitutions and conformational flexibility between
these enzymes. The carbonyl O atom of the DCI moiety was found to be oriented
away from the oxyanion hole, which greatly contributes to the stability of the
DCI:D adduct. The comparisons of the active sites between native factor D, DCI
inhibited factor D, and various inhibited trypsin and elastase (PPE) molecules
are providing the chemical bases directing our design of novel, small-molecule
pharmaceutical agents capable of modulating the alternative complement pathway.
PMID- 9757086
TI - Integrated software for a macromolecular crystallography synchrotron beamline.
AB - A package of software has been produced for the operation of the synchrotron
beamline X12-C at the National Synchrotron Light Source at Brookhaven National
Laboratory. Years of observing common user mistakes has enabled the production of
software that reduces user errors significantly. Users of the beamline
communicate with all the experimental apparatus, including both the data
collection equipment and the beamline components, including the monochromator,
through an easy-to-use graphical user interface (GUI). Important features of the
system are (1) its modularity, so that different underlying programs or different
apparatus can be incorporated easily; (2) its ease of use, minimizing both user
errors and training effort; and (3) that most of the experimental operations and
parameters are logged automatically, again minimizing errors and facilitating
more-or-less automatic reduction of the data. Features of the software are useful
enough to have been incorporated into operations at other synchrotron beamlines.
PMID- 9757088
TI - The refined structure of dUTPase from Escherichia coli.
AB - Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase, E.C. 3.6. 1.23)
catalyzes the hydrolysis of dUTP to dUMP and pyrophosphate and is involved in
nucleotide metabolism and DNA synthesis. A crystal of the recombinant E. coli
enzyme, precipitated from polyethylene glycol mixtures in the presence of
succinate at pH 4.2, was used to collect synchrotron diffraction data to 1.9 A
resolution, in space group R3, a = b = 86.62, c = 62.23 A. Mercury and platinum
derivative data were collected at wavelengths to optimize the anomalous
contribution. The resulting 2.2 A MIRAS phases differed from the final set by 40
degrees on average and produced an excellent map which was easy to interpret. The
model contains 132 water molecules and refined to an R value of 13.7%. 136
residues have clear electron density out of 152 expected from the gene sequence.
The 16 C-terminal residues are presumably disordered in the crystal lattice. The
monomer is a 'jelly-roll' type, containing mostly beta-sheet and only one short
helix. The molecule is a tight trimer. A long C-terminal arm extends from one
subunit and encompasses the next one within the trimer contributing to its beta
sheet. Conserved sequence motifs common among dUTPases, previously suggested to
compose the active site and confirmed in a recent study of the dUDP complex, are
located at subunit-subunit interfaces along the threefold axis, in parts of the
beta-sheet and in loop regions. A similar molecular architecture has recently
been found in two other trimeric dUTPases.
PMID- 9757089
TI - Modified phased translation functions and their application to molecular-fragment
location.
AB - Direct methods at high resolution have depended on the resolution of atomic like
features in the map. At data resolutions more typical for protein structures (2-3
A) individual atoms may not be resolved, so larger features must be identified.
At one extreme the whole molecule may be located using the diffraction magnitudes
alone by the molecular-replacement method. At the other extreme it is possible to
locate individual residues in a well phased map. In this paper an intermediate
problem is addressed: the location of multi-residue fragments on the basis of
weak phase information. An agreement function based on the mean-squared
difference between model and map over a masked region is shown to be more
effective than a simple overlap integral, and may be efficiently calculated by
Fourier methods. The techniques are compared using poorly phased electron-density
maps at approximately 3 A for the proteins RNAse and O6-methylguanine-DNA
methyltransferase.
PMID- 9757090
TI - Structure of the C-type lectin carbohydrate recognition domain of human
tetranectin.
AB - Tetranectin (TN) is a C-type lectin involved in fibrinolysis, being the only
endogenous ligand known to bind specifically to the kringle 4 domain of
plasminogen. TN was originally isolated from plasma, but shows a wide tissue
distribution. Furthermore, TN has been found in the extracellular matrix of
certain human carcinomas, whereas none or little is present in the corresponding
normal tissue. The crystal structure of full-length trimeric TN (2.8 A
resolution) has recently been published [Nielsen et al. (1997). FEBS Lett. 412,
388-396]. The crystal structure of the carbohydrate recognition domain (CRD) of
human TN (TN3) has been determined separately at 2.0 A resolution in order to
obtain detailed information on the two calcium binding sites. This information is
essential for the elucidation of the specificity of TN towards oligosaccharides.
TN3 crystallizes as a dimer, whereas it appears as a monomer in solution. The
overall fold of TN3 is similar to other known CRDs. Each monomer is built of two
distinct regions, one region consisting of six beta-strands and two alpha
helices, and the other region is composed of four loops harboring two calcium
ions. The calcium ion at site 1 forms an eightfold coordinated complex and has
Asp116, Glu120, Gly147, Glu150, Asn151, and one water molecule as ligands. The
calcium ion at site 2, which is believed to be involved in recognition and
binding of oligosaccharides, is sevenfold coordinated with ligands Gln143,
Asp145, Glu150, Asp165, and two water molecules. One sulfate ion has been located
at the surface of TN3, forming contacts to Glu120, Lys148, Asn106 of a symmetry
related molecule, and to an ethanol molecule.
PMID- 9757091
TI - Structures of monoclinic lysozyme iodide at 1.6 A and of triclinic lysozyme
nitrate at 1.1 A.
AB - Hen egg-white lysozyme is one of the most thoroughly studied of enzymes and has
been the subject of study by many methods, including X-ray crystallography. The
present work extends the X-ray crystallography to higher resolution, includes the
positions of the anions, and examines the contacts of the neighbors in greater
detail. Data were collected at room temperature on a Rigaku R-axis area detector
with rotating-anode X-ray generator to 1.6 A resolution for monoclinic lysozyme
iodide at pH 4.0, to 1.8 A for monoclinic lysozyme iodide at pH 8.0, and to 1.1 A
resolution for triclinic lysozyme nitrate at pH 4.5. The structures have been
refined by SHELX93 with the expected number of anion sites being accounted for.
Two regions of the protein have been found to be variable: residues 65-75 and 99
104. Except for 65-75 and 99-104, lysozyme is a very stable molecule with the
crystal forms being held together by the electrostatic contacts of the anions and
by layers of water molecules. The anion positions can be described as paired half
sites, each half being contributed by a different lysozyme molecule. The many
different crystal forms of lysozyme may be due to different combinations of the
many such half sites on the surface. A hypothesis is presented for lysozyme in
the different crystal forms and which may be extended to behavior in solution.
Suggestions for future crystallographic research are proposed, involving anions
of different shape and charge.
PMID- 9757092
TI - Structure of a non-psychrophilic trypsin from a cold-adapted fish species.
AB - The crystal structure of cationic trypsin (CST) from the Atlantic salmon (Salmo
salar) has been refined at 1.70 A resolution. The crystals are orthorhombic,
belong to space group P212121, with lattice parameters a = 65.91, b = 83.11 and c
= 154.79 A, and comprise four molecules per asymmetric unit. The structure was
solved by molecular replacement with AMoRe and refined with X-PLOR to an R value
of 17.4% and Rfree of 21.5% for reflections |F| > 3sigmaF between 8.0 and 1.7 A
resolution. The four non-crystallographic symmetry (NCS) related molecules in the
asymmetric unit display r.m.s. deviations in the range 0.31-0.74 A for main-chain
atoms, with the largest differences confined to two loops. One of these is the
calcium-binding loop where the electron-density indicates a calcium ion for only
one of the four molecules. In order to find structural rationalizations for the
observed difference in thermostability and catalytic efficiency of CST, anionic
salmon trypsin (AST) and bovine trypsin (BT), the three structures have been
extensively compared. The largest deviations for the superimposed structures
occur in the surface loops and particularly in the so-called 'autolysis loop'.
Both the salmon enzymes possess a high methionine content, lower overall
hydrophobicity and enhanced surface hydrophilicity, compared with BT. These
properties have so far been correlated to cold-adaptation features, while in this
work it is shown that the non-psychrophilic cationic salmon trypsin shares these
features with the psychrophilic anionic salmon trypsin.
PMID- 9757093
TI - The use of SnB to determine an anomalous scattering substructure.
AB - The positions of eight Se atoms in a selenomethionyl 35 kDa protein were
determined at 2.0 and 2.5 A resolution using the direct-methods program SnB. Data
at the selenium peak, edge and remote wavelengths were measured and processed
independently. Anomalous difference E magnitudes at each wavelength were derived
by two different procedures: renormalized diffE values were calculated according
to the equation diffE = ?sigma[(f + f')2 + f"2]||E+|-|E-||?1/2/2q(sigma f"2)1/2,
where q is a least-squares fitted renormalization function of sinstraight
theta/lambda such that = 1.0; and difference E magnitudes were
calculated from DeltaF2. Locally normalized E magnitudes corresponding to |FA|
were also derived from the combination of the data at all three wavelengths
through the use of the MADSYS program suite. Each of the independent sets of
anomalous difference E magnitudes was capable of producing the correct solution,
as did the E data obtained from the FA data. Higher success rates with SnB were
observed for the 2.0 A peak and edge diffE data.
PMID- 9757094
TI - Structure of bacteriophage T4 fibritin M: a troublesome packing arrangement.
AB - Fibritin, a 52 kDa product of bacteriophage T4 gene wac, forms 530 A long fibers,
named whiskers, that attach to the phage neck and perform a helper function
during phage assembly. Fibritin is a homotrimer, with its predominant central
domain consisting of 12 consecutive alpha-helical coiled-coil segments linked
together by loops. The central domain is flanked by small globular domains at
both ends. Fibritin M is a genetically engineered fragment of the wild type and
contains 74 amino-acid residues corresponding to the last coiled-coil segment and
the complete carboxy-terminal domain. The crystals of fibritin M belong to the
rare space group P3 with three crystallographically independent trimers in the
unit cell. The structure has been established at 1.85 A resolution by combining
molecular and isomorphous replacement techniques. One of the two heavy-atom
derivatives used was gaseous xenon. A substantial fraction of residues in each
independent trimer is disordered to various extents in proportion to the lack of
restraints on the molecules provided by the lattice contacts. Accurate modeling
of the solvent present in the crystals was crucial for achieving good agreement
with experimental data.
PMID- 9757095
TI - On the use of strong Patterson function signals in many-body molecular
replacement.
AB - The symmetry elements detected by the self-rotation and the Patterson functions,
associated to strong correlations between the positions of the molecules in the
asymmetric unit, are used to reduce the effective number of independent bodies to
be located by the molecular replacement method. A distinction is made between
'frustrated' crystallographic symmetries, i.e. those that are almost
crystallographic ones, and 'standard' non-crystallographic symmetries, which are
taken into account by specific techniques. These have been successfully applied
to many-body macromolecular crystal structures, with important savings in time
and computational effort.
PMID- 9757097
TI - STEP--a trial-and-error procedure for crystal structure determination. II. The
determination of two small protein structures.
AB - This paper describes the difficulties in the process of using the trial-and-error
SYSTEM90 program to determine ab initio the structures of two small proteins App
[Woolfson & Yao (1990). Acta Cryst. A46, 409-413] and rubredoxin [Sheldrick et
al. (1993). Acta Cryst. D49, 18-23] with high-resolution data. Some strategies
for overcoming the difficulties are discussed and the upgraded SYSTEM95 program
was used successfully to determine the two structures. The most characteristic
feature of this structure-determination process is that the two proteins are
treated as unknown structures with only their chemical compositions and high
resolution data sets known. A new figure of merit R(sc), replacing the old figure
of merit, XDFOM, is quite effective in picking out a good set of phases in the
multi-solution stage when the phases are overconsistent. Controlling the Fourier
recycling technique and the residuals can separate the mixture of structures and
the enantiomorph and finally give one absolute structure. The results are
compared with known structures to verify their reliability.
PMID- 9757096
TI - Detection and use of pseudo-translation in determination of protein structures.
AB - Two types of pseudo-translation symmetry, pseudo-twofold translational symmetry
and pseudo-body-centered symmetry, have been found in protein crystals of
chorismate mutase and cyclophilin C. Statistics on diffraction intensity from
these two crystals showed that the presence of pseudo-translations in atomic
space yielded a distribution of systematically strong and weak reflections at low
resolution. The diffraction pattern resulting from pseudo-translational symmetry
was apparently similar to that from true crystallographic symmetry at 4 A
resolution, but was distinct at high resolution. Pseudo-translation can be
detected by comparing the average magnitudes of certain parity groups of
reflections in three-dimensional hkl space. Based on the structures of chorismate
mutase and cyclophilin C, the ratio of >1.2 for the average magnitudes of parity
groups is sufficient to indicate the existence of pseudo-translation. Although
pseudo-translation often makes structure determination more difficult, the
additional information of pseudo-translation has been used successfully in the
structure determination of chorismate mutase by multiple isomorphous replacement
and of cyclophilin C by molecular replacement. Thus, examination of pseudo
translation is recommended at an early stage of structure determination.
PMID- 9757098
TI - X-ray structure of human lysozyme labelled with 2',3'-epoxypropyl beta-glycoside
of man-beta1,4-GlcNAc. Structural change and recognition specificity at subsite
B.
AB - Human lysozyme (HL) labelled with the 2',3'-epoxypropyl beta-glycoside of Man
beta1,4-GlcNAc was crystallized at pH 4.5. The cell dimensions were a = 36.39, b
= 116.38, c = 30.91 A and the space group was P212121. The unit cell contained
four molecules (Vm = 2.18 A3 Da-1). The crystal structure was determined by
molecular replacement and refined to an R value of 0.168 for 7060 reflections
[|Fo| > 3sigma(F)] in the resolution range 8.0-2.1 A. A prominent shift of the
Calpha-atom positions by up to 3.8 A in the region of residues 45-50 was observed
compared with wild-type HL. Owing to the conformational change in this region the
intermolecular contacts were altered remarkably compared to wild-type HL,
explaining the difference in molecular packing. The Man-beta1,4-GlcNAc moiety
occupied subsites B and C in the substrate-binding site of HL. Several
differences in the hydrogen-bonded contacts between the ligand part and the
protein part were observed for HL labelled with the 2',3'-epoxypropyl beta
glycoside of Man-beta1,4-GlcNAc compared with HL labelled with the corresponding
derivatives of GlcNAc-beta1, 4-GlcNAc and Gal-beta1,4-GlcNAc. In contrast to the
replacement of GlcNAc with Gal, the replacement of GlcNAc with Man did not
sacrifice the stacking interactions with the side-chain group of Tyr63 as
determined by the parallelism of the apolar face of the carbohydrate residue and
the aromatic plane of the Tyr63 side chain. The 2',3'-epoxypropyl beta-glycoside
of Man-beta1,4-GlcNAc exhibited almost the same affinity towards HL as Gal
beta1,4-GlcNAc, a much lower affinity than that of GlcNAc-beta1,4-GlcNAc. The
difference in the protein-ligand interactions was discussed in relation to the
carbo-hydrate-residue recognition specificity at subsite B of HL. The results
suggested that Gln104 was a determinant for the strong recognition of GlcNAc
residue at subsite B in HL.
PMID- 9757099
TI - Quaternary structure of UEA-II, the chitobiose specific lectin from gorse.
AB - The chitobiose specific Ulex europaeus lectin II crystallizes in space group
P3221 with unit-cell dimensions a = b = 105.54, c = 176.26 A. The asymmetric unit
contains a complete lectin tetramer. The crystals were shown to diffract to 4.5 A
on a rotating-anode source and to 2.7 A at the Daresbury synchrotron source.
Molecular replacement and subsequent rigid-body refinement using data to 4.5 A
yielded a solution corresponding to a tetramer very similar to that of
phytohemagglutinin-L and soybean agglutinin. The monomers in the Ulex lectin
tetramer are rotated approximately 5 degrees compared with the phytohemagglutinin
L and soybean agglutinin structures.
PMID- 9757100
TI - A description of imperfections in protein crystals.
AB - An analysis is given of the contribution of various crystal imperfections to the
rocking widths of reflections and the divergence of the diffracted beams. The
crystal imperfections are the angular spread of the mosaic blocks in the crystal,
the size of the mosaic blocks and the variation in cell dimensions between
blocks. The analysis has implications for improving crystal perfection, defining
data-collection requirements and for data-processing procedures. Measurements on
crystals of tetragonal lysozyme at room temperature and 100 K were made in order
to illustrate how parameters describing the crystal imperfections can be
obtained. At 100 K, the dominant imperfection appeared to be a variation in unit
cell dimensions in the crystal.
PMID- 9757101
TI - Structure of glucoamylase from Saccharomycopsis fibuligera at 1.7 A resolution.
AB - The yeast Saccharomycopsis fibuligera produces a glucoamylase which belongs to
sequence family 15 of glycosyl hydrolases. The structure of the non-glycosyl-ated
recombinant enzyme has been determined by molecular replacement and refined
against 1.7 A resolution synchrotron data to an R factor of 14.6%. This is the
first report of the three-dimensional structure of a yeast family 15
glucoamylase. The refinement from the initial molecular-replacement model was not
straightforward. It involved the use of an unrestrained automated refinement
procedure (uARP) in combination with the maximum-likelihood refinement program
REFMAC. The enzyme consists of 492 amino-acid residues and has 14 alpha-helices,
12 of which form an (alpha/alpha)6 barrel. It contains a single catalytic domain
but no starch-binding domain. The fold of the molecule and the active site are
compared to the known structure of the catalytic domain of a fungal family 15
glucoamylase and are shown to be closely similar. The active- and specificity
site residues are especially highly conserved. The model of the acarbose
inhibitor from the analysis of the fungal enzyme fits tightly into the present
structure. The active-site topology is a pocket and hydrolysis proceeds with
inversion of the configuration at the anomeric carbon. The enzyme acts as an exo
glycosyl hydrolase. There is a Tris [2-amino-2-(hydroxymethyl)-1,3-propanediol]
molecule acting as an inhibitor in the active-site pocket.
PMID- 9757103
TI - Accessing lysozyme nucleation with a novel dynamic light scattering detector.
AB - Dynamic light scattering was employed to investigate the behaviour of nucleating
hen egg-white lysozyme solutions. For these studies we employed a novel fiber
optic based microprobe that suppresses multiple light scattering and
contributions from large clusters in the spectra by backscattering detection. The
time evolution of small lysozyme clusters is found to obey classical nucleation
at the initial stages of the reaction.
PMID- 9757102
TI - Nucleation in protein crystallization.
AB - In this paper protein crystallization is regarded as a process starting with
phase separation in a two-component system. The nucleation time of a lysozyme
solution is measured by recording the NMR spectra of crystallizing solutions as a
function of time. It is found that there is an appreciable induction time before
the first nuclei appear in the solution and that this induction time depends
strongly on the degree of supersaturation due to the protein concentration at a
given ionic strength or due to the temperature. From the experimental data it is
evident that (at least for lysozyme) crystallization under the prevailing
experimental conditions is a transient process with an induction time and not a
steady-state process.
PMID- 9757104
TI - Structure determination of the phiX174 closed procapsid.
AB - The structure of a procapsid of the single-stranded DNA bacteriophage ++phiX174
was determined to 3.5 A resolution. The crystal space group was I213 with a unit
cell length of 774 A. The unit cell contained 16 icosahedral virus particles,
each situated on a crystallographic threefold axis. Thus, there are two
independent one-thirds of a particle per asymmetric unit, and a total of 40-fold
non-crystallographic redundancy. To aid in the interpretation of the packing
arrangement, crystals were prepared for thin sectioning and analyzed by electron
microscopy. Oscillation X-ray diffraction data was collected on image plates
using synchrotron radiation and oscillation angles of either 0.25 or 0.30
degrees. A low-resolution 6.5 A data set collected from a single frozen crystal
was particularly helpful in the structure determination, because of its
completeness and internal consistency. The initial particle orientations were
determined using self-rotation functions, while the initial position of one
particle was determined from a Patterson map. The structure was solved by
molecular replacement real-space averaging using a model based on a cryo-electron
microscopy reconstruction as a starting point for the phase determination. The
initial structure determination used the data between 20 and 13 A resolution,
which was then extended one reciprocal lattice point at a time to 6.5 A
resolution. At this point, a 3.5 A resolution data set compiled from a number of
crystals collected at 277 K was introduced. Phase extension and averaging
continued to 3.5 A resolution after re-determining the particle positions and
orientations. The amino-acid sequences of most of the D, F and G proteins and
part of the B protein could be unambiguously built into the 3.5 A electron
density map. Partial crystallographic refinement yielded an R factor of 31.6%,
consistent with the relatively low resolution and lack of completeness of the
data.
PMID- 9757105
TI - Structure of ubiquitin-conjugating enzyme 9 displays significant differences with
other ubiquitin-conjugating enzymes which may reflect its specificity for sumo
rather than ubiquitin.
AB - The three-dimensional structure of ubiquitin-conjugating enzyme 9 (Ubc9) has been
obtained to a resolution of 2.8 A by molecular replacement followed by a
combination of automated refinement and graphical intervention. Diffraction data
were recorded on a single crystal in space group P43 with cell dimensions a = b =
73.9, c = 42. 9 A. The final model has an R factor of 21.3% for all data to 2.8
A. Only the N-terminal methionine, a two-residue N-terminal extension and a four
residue loop are not located by the final electron-density map. Ubc9 is now known
to be the first sumo, a new ubiquitin-like protein, conjugating enzyme and does
not conjugate ubiquitin. The structure of Ubc9 shows important differences
compared with the structures of known ubiquitin-conjugating enzymes. At the N
terminal helix, the structural and sequence alignments are out of register by one
amino acid giving Ubc9 a different recognition surface compared to ubiquitin
conjugating enzymes. This is coupled to a profound change in the electrostatic
surface of the molecular face remote from the catalytic site. These differences
may be important in recognition of other proteins in the Sumo conjugation
pathway. The catalytic cysteine in Ubc9 has a positively charged lip and a
negatively charged ridge nearby. Both these features seem confined to sumo
conjugating enzymes, and a sequence alignment of sumo and ubiquitin suggests how
these might play a role in sumo/ubiquitin discrimination.
PMID- 9757106
TI - Locations of bromide ions in tetragonal lysozyme crystals.
AB - Anions have been shown to play a dominant role in the crystallization of chicken
egg-white lysozyme from salt solutions. Previous studies employing X-ray
crystallography have found one chloride ion binding site in the tetragonal
crystal form of the protein and four nitrate ion binding sites in the monoclinic
form. In this study the anion positions in the tetragonal form were determined
from the difference Fourier map obtained from lysozyme crystals grown in bromide
and chloride solutions. Five possible anion-binding sites were found in this
manner. Some of these sites were in pockets containing basic residues while
others were near neutral, but polar, residues. The sole chloride ion binding site
found in previous studies was confirmed, while four further sites were found
which corresponded to the four binding sites found for nitrate ions in monoclinic
crystals. The study suggests that most of the anion-binding sites in lysozyme
remain unchanged even when different anions and different crystal forms of
lysozyme are employed.
PMID- 9757107
TI - Crystallography & NMR system: A new software suite for macromolecular structure
determination.
AB - A new software suite, called Crystallography & NMR System (CNS), has been
developed for macromolecular structure determination by X-ray crystallography or
solution nuclear magnetic resonance (NMR) spectroscopy. In contrast to existing
structure-determination programs, the architecture of CNS is highly flexible,
allowing for extension to other structure-determination methods, such as electron
microscopy and solid-state NMR spectroscopy. CNS has a hierarchical structure: a
high-level hypertext markup language (HTML) user interface, task-oriented user
input files, module files, a symbolic structure-determination language (CNS
language), and low-level source code. Each layer is accessible to the user. The
novice user may just use the HTML interface, while the more advanced user may use
any of the other layers. The source code will be distributed, thus source-code
modification is possible. The CNS language is sufficiently powerful and flexible
that many new algorithms can be easily implemented in the CNS language without
changes to the source code. The CNS language allows the user to perform
operations on data structures, such as structure factors, electron-density maps,
and atomic properties. The power of the CNS language has been demonstrated by the
implementation of a comprehensive set of crystallographic procedures for phasing,
density modification and refinement. User-friendly task-oriented input files are
available for nearly all aspects of macromolecular structure determination by X
ray crystallography and solution NMR.
PMID- 9757108
TI - X-ray topographic studies of protein crystal perfection and growth.
AB - The effects of solution variations during growth on the perfection of tetragonal
lysozyme crystals have been characterized using X-ray topography and high angular
and wavevector resolution reciprocal-space scans. X-ray images of crystals grown
under nearly uniform conditions show little contrast or evidence of defects, and
mosaic widths of these crystals are comparable with those reported for
microgravity-grown crystals. Images of crystals for which solution conditions
(temperature, pH or salt concentration) are changed after an initial period of
uniform growth can show extensive contrast, indicating the presence of disorder.
The X-ray mosaic widths of these crystals can be significantly broadened, but
their radial widths are at most very slightly broadened, indicating that image
contrast is primarily due to mosaicity. Comparison of X-ray images with mosaic
scans indicates that regions grown after the change in solution conditions have
broader mosaicities and are more disordered; that regions grown immediately after
the change tend to have broader mosaicities than subsequent growth regions; and
that the pre-change growth region is largely unaffected by solution changes. The
observed disorder may arise from solution change-related transient growth
instabilities, from transient liquid-liquid phase separation that can occur
during the change, and from post-change relaxation of the lattice constant of the
pre-change growth regions. These results suggest that solution variations during
growth, including those typical of macroseeding, vapor-diffusion growth and other
widely used techniques, may be an important source of disorder in some protein
crystals.
PMID- 9757109
TI - Continuous and discontinuous changes in the unit cell of HIV-1 reverse
transcriptase crystals on dehydration.
AB - A crystal form of HIV-1 reverse transcriptase (RT) complexed with inhibitors
showed diffraction to a high-resolution limit of 3.7 A. Instability in the unit
cell dimensions of these crystals was observed during soaking experiments, but
the range of this variability and consequent change in lattice order was revealed
by a chance observation of dehydration. Deliberately induced dehydration results
in crystals having a variety of unit cells, the best-ordered of which show
diffraction to a minimum Bragg spacing of 2.2 A. In order to understand the
molecular basis for this phenomenon, the initial observation of dehydration, the
data sets from dehydrated crystals, the crystal packing and the domain
conformation of RT are analysed in detail here. This analysis reveals that the
crystals undergo remarkable changes following a variety of possible dehydration
pathways: some changes occur gradually whilst others are abrupt and require
significant domain rearrangements. Comparison of domain arrangements in different
crystal forms gives insight into the flexibility of RT which, in turn, may
reflect the internal motions allowing this therapeutically important enzyme to
fulfill its biological function.
PMID- 9757110
TI - Recognition of RNase Sa by the inhibitor barstar: structure of the complex at 1.7
A resolution.
AB - We report the 1.7 A resolution structure of RNase Sa complexed with the
polypeptide inhibitor barstar. The crystals are in the hexagonal space group P65
with unit-cell dimensions a = b = 56.9, c = 135.8 A and the asymmetric unit
contains one molecule of the complex. RNase Sa is an extracellular microbial
ribonuclease produced by Streptomyces aureofaciens. Barstar is the natural
inhibitor of barnase, the ribonuclease of Bacillus amyloliquefaciens. It inhibits
RNase Sa and barnase in a similar manner by steric blocking of the active site.
The structure of RNase Sa is very similar to that observed in crystals of the
native enzyme and its complexes with nucleotides. Barstar retains the structure
found in its complex with barnase. The accessible surface area of protein buried
in the complex is about 300 A2 smaller and there are fewer hydrogen bonds in the
enzyme-inhibitor interface in RNase Sa-barstar than in barnase-barstar, providing
an explanation of the reduced binding affinity in the former. Previous studies of
barstar complexes have used mutants of the inhibitor and this is the first
structure which includes wild-type barstar.
PMID- 9757111
TI - Structure of dimeric and monomeric erabutoxin a refined at 1.5 A resolution.
AB - Erabutoxin a has been crystallized in its monomeric and dimeric forms. The
structures were refined at 1.50 and 1.49 A resolution, respectively, using
synchrotron radiation data. The crystals belong to space group P212121, with cell
dimensions a = 49.84, b = 46.62, c = 21.22 A for the monomer and a = 55.32, b =
53.54, c = 40.76 A for the dimer. Using starting models from earlier structure
determinations, the monomeric structure refined to an R value of 16.7% (8004
unique reflections, 17.0-1.50 A resolution range), while the dimeric structure
has been solved by the molecular-replacement method with a final R value of 16.9%
(19 444 unique reflections, 17.4-1.49 A resolution range). The high-resolution
electron-density maps clearly revealed significant discrete disorder in the
proteins and allowed an accurate determination of the solvent structure. For the
monomer, the side chains of six residues were modelled with alternate conformers
and 106 sites for water molecules and one site for a sulfate ion were included in
the final model, whereas for the dimer, 206 sites for water molecules were
included and both C-terminal residues together with the side chains of 11
residues adopted alternative conformations. A comparison was made with earlier
structure determinations. The features of the solvent structure of the erabutoxin
molecules are discussed in detail.
PMID- 9757112
TI - Crystallization of ccdB.
AB - CcdB is a small dimeric protein that poisons DNA-topoisomerase II complexes. Its
crystallization properties in terms of precipitant type, precipitant
concentration, pH and protein concentration have been investigated leading to a
novel crystal form which, in contrast to previously reported crystals, is
suitable for structure determination using the multiple isomorphous replacement
(MIR) method. The space group of this new form is C2, with unit-cell parameters a
= 74.94, b = 36.24, c = 35.77 A, beta = 115.27 degrees. The asymmetric unit
contains a single monomer. Flash-frozen crystals diffract to at least 1.5 A
resolution, while room-temperature diffraction can be observed up to 1.6 A. The
double mutant S74C/G77Q, which acts as a super-killer, crystallizes in space
group I222 (or I212121) with unit-cell dimensions a = 105.58, b = 105.80, c =
91.90 A. These crystals diffract to 2.5 A resolution.
PMID- 9757113
TI - Crystallization and preliminary X-ray analysis of pig E3, lipoamide
dehydrogenase.
AB - Pig heart lipoamide dehydrogenase was crystallized by the hanging-drop vapor
diffusion method. X-ray diffraction patterns show that the hexagonal crystals
have unit-cell dimensions of a = b = 359. 3, c = 140.5 A. The crystal structure
has been preliminarily solved by the molecular-replacement method in the space
group P6322. Three dimeric molecules have been found in the asymmetric unit, one
of them located on the crystallographic twofold axis.
PMID- 9757114
TI - Purification, crystallization and preliminary X-ray crystallographic analysis of
Pyrococcus furiosus DNA polymerase.
AB - DNA polymerase gene from the hyperthermophilic Archaeon Pyrococcus furiosus has
been cloned and the protein overexpressed in Escherichia coli to produce an
active enzyme. The purified protein was crystallized from 0.08 M ammonium
sulfate, 0.05 M Na-cacodylate, pH 6.5, 0.15%(v/v) NP40, 0.05%(v/v) Tween 20 and
4.5%(w/v) polyethylene glycol 6000 by the vapour-diffusion method. The
orthorhombic crystals had unit-cell dimensions of a = 92.5, b = 125.4, c = 192.1
A; alpha = beta = gamma = 90 degrees. The crystals diffracted beyond 4 A on a
1.08 A synchrotron radiation source.
PMID- 9757115
TI - Purification, crystallization and preliminary crystallographic analysis of bovine
cytosolic brain-type creatine kinase.
AB - Creatine kinase (E.C. 2.3.7.2) is an important enzyme in energy metabolism which
catalyzes the reversible transfer of a phosphoryl group between phosphocreatine
and ADP to give ATP. Large quantities of a brain-type creatine kinase have been
isolated from bovine photoreceptor cells and crystals suitable for X-ray
diffraction analysis have been obtained by hanging-drop vapor diffusion. Crystals
grow as tetragonal bipyramids in space group P43212 with cell dimensions a = b =
96.49, c = 108.42 A and diffract to at least 2.7 A resolution.
PMID- 9757116
TI - Crystallization and preliminary X-ray crystallographic studies of the plant
aspartic proteinase cardosin A.
AB - The plant aspartic proteinase cardosin A was crystallized using vapour diffusion.
Crystals belong to the monoclinic space group C2, cell dimensions a = 116.9 (2),
b = 87.2 (8), c = 81.3 (1) A, beta = 104.4 (4) degrees, and contain two molecules
in the asymmetric unit related by a non-crystallographic twofold axis.
Diffraction data were collected at room temperature with radiation from a
synchrotron source up to 2.85 A resolution. When the crystals were flash cooled
to 110 K in a nitrogen stream the same resolution limit could also be obtained on
a rotating-anode source. Recently, synchrotron radiation together with flash
cooling led to an improvement of the diffraction data to 1.72 A resolution.
PMID- 9757117
TI - Crystallization and preliminary diffraction analysis of a hyperthermostable DNA
polymerase from a Thermococcus archaeon.
AB - The hyperthermostable DNA polymerase from a marine Thermococcus archaeon has been
crystallized in space group P212121, with unit-cell dimensions a = 94.8, b =
98.2, c = 112.2 A with one molecule per asymmetric unit. Conditions for data
collection at 98 K have been identified, and a complete data set was collected to
2.2 A resolution. Strategies employed here may facilitate crystallization of
other hyperthermostable proteins. The structure of this enzyme will provide the
first structural data on the archaeal and hyperthermostable classes of DNA
polymerases. Sequence homology to human polymerase alpha (polymerase B family)
may make it a model for studying eukaryotic and viral polymerases and for the
development of anti-cancer and anti-viral therapeutics.
PMID- 9757118
TI - Crystallization and preliminary X-ray analysis of Escherichia coli GlnK.
AB - The trimeric signal-transduction protein GlnK, from Escherichia coli, has been
over-expressed, purified to homogeneity and crystallized. The crystals belong to
space group P213 with a = 85.53 A and have two subunits in the asymmetric unit.
The complex of GlnK with ATP crystallized in space group P63 with a = 57.45 and c
= 54.79 A. These crystals have a single subunit in the asymmetric unit. High
quality diffraction data from crystals of GlnK and the GlnK complex have been
collected to 2.0 A.
PMID- 9757119
TI - Crystallization and preliminary X-ray crystallographic analysis of the EGF
receptor ectodomain.
AB - Crystallization of the hydrophilic ectodomain of the epidermal growth factor
(EGF) receptor has been accomplished in the presence of the ligand EGF. Two
different crystal forms have been obtained, one of which was suitable for X-ray
analysis. The space group of this form has been assigned to P21212 with unit-cell
dimensions of a = 207.4, b = 113.3 and c = 120.4 A. A native data set has been
recorded and a heavy-atom search is currently under way. Diffraction from these
crystals, however, is limited to low resolution and extensive trials to improve
crystal quality further have all failed. To analyse the molecular shape and
aggregation of the receptor protein in solution, small-angle X-ray diffraction
and dynamic light-scattering techniques have been applied. Synchrotron radiation
in combination with cryo-techniques is essential for data collection because of
the high solvent content and radiation sensitivity.
PMID- 9757120
TI - Crystallization and preliminary X-ray diffraction studies of DNA polymerase from
the thermophilic archaeon Sulfolobus solfataricus.
AB - The thermophilic and thermostable family B DNA polymerase from the archaeon
Sulfolobus solfataricus (Mr of about 100 kDa) has been crystallized by the
hanging-drop vapour-diffusion method at 294 K using ammonium sulfate as
precipitant. The crystals belong to the monoclinic space group C2 with cell
dimensions a = 187.4, b = 68.5, c = 125.8 A and beta = 107.8 degrees and diffract
up to 2.7 A resolution on a rotating-anode X-ray source. Native data have been
collected at 100 K. A heavy-atom derivative search is in progress.
PMID- 9757121
TI - Crystallization and preliminary X-ray diffraction analysis of antigen-binding
fragments which are specific for antigenic conformations of sialic acid
homopolymers.
AB - Meningococcal meningitis is a severe childhood disease which often results in
significant disability or death. Two major etiological agents of meningitis are
the group B meningococci and capsular type K1 E. coli. The virulence of these
organisms is attributable to structural mimicry between their common alpha(2-8)
polysialic acid capsular polysaccharide and human tissue antigens, which allows
the bacteria to evade immune surveillance. There is currently no effective
vaccine to protect against this infection. It has been demonstrated that the
capsular polysaccharide of the bacteria can adopt a unique 'antigenic
conformation'. This antigenic conformation has formed the basis for the
development of an N-propionylated polysialic acid vaccine. Immunization trials in
mice with this vaccine show the production of two groups of antibodies, of which
only N-propionylated polysialic acid-specific were protective. Knowledge of the
structure of the antigen-binding site which recognizes the protective epitope is
essential to determining the antigenic conformation of the polysaccharides, and
is a critical aspect in understanding and improving the action of potential
vaccines. The antigen-binding fragments (Fab) of one protective (13D9) and one
non-protective (6B9) monoclonal antibody specific for the capsular
polysaccharides of group B meningococci have been crystallized and have undergone
preliminary X-ray diffraction analysis. Both crystals are observed to scatter X
rays to approximately 1.7 A resolution at the A1 station at the Cornell High
Energy Synchrotron Source. 13D9 has an orthorhombic unit cell with a = 41.8, b =
102.3, c = 134.7 A, with space group P212121. Fab 6B9 has an orthorhombic unit
cell with a = 89.6, b = 132.0 and c = 36.9 A, with space group P21212.
PMID- 9757122
TI - Crystallization and preliminary X-ray crystallographic studies of the 13-fold
symmetric portal protein of bacteriophage SPP1.
AB - Portal proteins are cyclical oligomers which play essential roles in
bacteriophage pro-capsid formation, DNA packaging, and in connector formation.
Bacteriophage SPP1 portal protein (gp6) is a turbine-like molecule with 13-fold
symmetry [Dube et al. (1993) EMBO J. 12, 1303-1309]. The purified protein was
crystallized with polyethylene glycol 400 as the precipitating agent using the
vapor-diffusion method. Salt conditions were selected based on the properties of
gp6 in different ionic environments. X-ray diffraction data up to a resolution of
7.85 A were measured from frozen crystals with orthorhombic space group C2221 and
cell dimensions a = 180.5 (5), b = 223.5 (5), c = 417 (1) A. The asymmetric unit
contains one tridecameric portal protein with 57.3 kDa subunits. The self
rotation searches confirm the 13-fold symmetry of the crystallized protein.
PMID- 9757123
TI - Preliminary crystallographic studies of citrate synthase from an Antarctic
psychrotolerant bacterium.
AB - Recombinant citrate synthase from a psychrotolerant bacterium, DS2-3R, recently
isolated in Antarctica, has been crystallized. The crystals belong to space group
P6122 or P6522, with cell dimensions a = b = 70.8, c = 307.8 A. Diffraction data
collected on a synchrotron from a cryoprotected crystal extends to at least 2.0
A. Knowledge of the structure of this enzyme will add to the understanding of
cold activity and thermolability, and will be of biotechnological interest.
Previously, the structure of citrate synthase from Archaea inhabiting
environments at 328 and 373 K, has been reported. This present study will extend
our understanding of the structural integrity and activity of proteins at the
temperature extremes of life.
PMID- 9757124
TI - Crystallographic characterization of Pap1-DNA complex.
AB - Pap1 is a fission yeast transcription factor that activates genes related with
resistance against staurosporine, a potent inhibitor of protein kinase C, and has
been shown to be involved in cell growth, cell cycle, carcinogenesis and
differentiation. Pap1 has the bZIP DNA-binding domain but binds to non-consensus
DNA sequences for the bZIP motif. Highly ordered crystals of the DNA-binding
domain complexed with a DNA fragment that has an ATF/CREB-like non-consensus
sequence have been obtained. The crystals grew by the vapor-diffusion technique
with polyethylene glycol 6000 and belong to space group R3 with a = b = 240.78, c
= 43.85 A. A 2.0 A resolution data set was collected with a cryo-crystallographic
technique.
PMID- 9757125
TI - Crystallization and preliminary X-ray diffraction studies on the water soluble
form of rat heme oxygenase-1 in complex with heme.
AB - The water-soluble portion of rat heme oxygenase-1 which lacks 22 hydrophobic
amino-acid residues at the C-terminus was expressed in E. coli and crystallized
in the form of a complex with heme by the vapor-diffusion method using
polyethylene glycol 4000 as the precipitant. The crystals belong to the
tetragonal space group P41212 or P43212, with unit-cell dimensions of a = b =
56.7, c = 186. 7 A. The crystal contains one heme-heme oxygenase-1 complex in an
asymmetric unit and diffracts X-rays beyond 3.0 A resolution with a conventional
X-ray source.
PMID- 9757126
TI - Crystallization and preliminary X-ray analysis of the beta-isoform of glutamate
decarboxylase from Escherichia coli.
AB - Glutamate decarboxylase (GAD) is a vitamin B6 enzyme which catalyzes the alpha
decarboxylation of L-glutamate to gamma-aminobutyric acid (GABA). Escherichia
coli cells coexpress two highly homologous enzyme isoforms, GADalpha and GADbeta.
Well diffracting crystals of GADbeta were obtained by taking advantage of the
possibility of expressing each isoform separately. They belong to space group P31
or P32 with the unit-cell dimensions a = b = 115.6 and c = 206.6 A and contain
one GAD hexamer in the asymmetric unit. High-resolution synchrotron data were
collected at 100 K for the native protein and a potential heavy-atom derivative.
PMID- 9757127
TI - Crystallization of succinylated concanavalin A bound to a synthetic bivalent
ligand and preliminary structural analysis.
AB - Crystals have been obtained of succinylated concanavalin A complexed to a novel
bidentate synthetic ligand. The crystals are the first example of a lectin with a
synthetic multivalent ligand and the first report of crystallization of
succinylated concanavalin A. The crystals were obtained by sitting-drop vapour
diffusion equilibrating with a solution of 20% polyethylene glycol, pH 5, 293. 5
K. Crystals are orthorhombic, belonging to space group C2221 with unit-cell
dimensions of a = 99.1, b = 127.4, c = 118.9 A. The asymmetric unit contains a
dimer, with over 65% of the volume occupied by water. The ligand cross links
concanavalin A monomers. Succinylated concanavalin A is known to be a dimer in
solution, yet it is found as the typical concanavalin A tetramer in the crystal.
The contacts holding together the tetramer appear extensive and suggest that a
fine balance between dimer and tetramers exists. Data to 2.65 A have been
collected and the structure determined by the molecular replacement method.
PMID- 9757128
TI - Crystallization and preliminary X-ray diffraction studies of the heterogeneously
glycosylated enzyme rhamnogalacturonan acetylesterase from Aspergillus aculeatus.
AB - Well diffracting crystals of rhamnogalacturonan acetylesterase from Aspergillus
aculeatus have been obtained in two polymorphic modifications despite its
heterogeneous glycosylation. The best-diffracting crystals (resolution 1.55 A)
are orthorhombic. The limit of the diffraction pattern of the other (trigonal)
form is 2.5 A. The ability of the enzyme to crystallize appears to depend on the
glycosylation of the protein sample. This aspect has been investigated by mass
spectrometry, which also showed that the orthorhombic crystals have the same
glycosylation as the protein sample used in the crystallization.
PMID- 9757129
TI - Purification, crystallization and preliminary X-ray analysis of human recombinant
cytosolic serine hydroxymethyltransferase.
AB - As an enzyme of the thymidylate synthase cycle, serine hydroxymethyltransferase
(SHMT) has a key role in nucleotide biosynthesis. Elevated activities of SHMT
have been correlated with the increased demand for nucleotide biosynthesis in
tumors of human and rodent origin, making this enzyme a novel target for cancer
chemotherapy. Here the purification and crystallization of recombinant human
cytosolic SHMT are reported. Crystals belong to space group P6222 or P6422 with
cell parameters a = b = 155.0, c = 235.5 A and diffract to at least 3.0 A
resolution.
PMID- 9757130
TI - Crystallization and preliminary X-ray characterization of aspartate
aminotransferase from an extreme thermophile, Thermus thermophilus HB8.
AB - Recombinant aspartate aminotransferase from an extremely thermophilic bacterium,
Thermus thermophilus HB8, has been crystallized in two different crystal forms.
The crystals of both forms are orthorhombic and belong to space group P212121
with cell dimensions a = 124.3, b = 113.6 and c = 61.6 A for form I and a =
197.3, b = 109.7 and c = 80.3 A for form II. The crystals of form I and II
diffract to 2.1 and 2.5 A resolution, respectively, on a conventional laboratory
rotating-anode source. Two heavy-atom derivatives have been identified for form
I.
PMID- 9757131
TI - Crystallization and preliminary X-ray diffraction studies of the oxygenating
subunit of 3,6-diketocamphane monooxygenase from Pseudomonas putida.
AB - The oxygenating constituent of the 3,6-diketocamphane monooxygenase isozyme from
Pseudomonas putida NCIMB 10007 has been crystallized under two different
conditions. Crystals were initially grown from polyethylene glycol (PEG) 8000 and
sodium acetate using the vapour-phase diffusion method. The crystals were of
orthorhombic P212121 space group, with cell dimensions a = 55.8, b = 94.5 and c =
163.7 A and diffracted to 2.8 A resolution. More recently, improved crystals,
which diffracted beyond 2 A, have been grown from ammonium sulfate. These
crystals also belong to the orthorhombic P212121 space group, with cell
dimensions of a = 54.6, b = 93.2 and c = 154. 1 A. A full native data set to 2.5
A resolution has been collected from the ammonium sulfate grown crystals.
PMID- 9757132
TI - Crystallization and preliminary X-ray analysis of recombinant glutamate mutase
and of the isolated component S from Clostridium cochlearium.
AB - Glutamate mutase [varepsilon2sigma2(B12)1] was reconstituted by incubating
purified components E (varepsilon2) and S (sigma2) from Clostridium cochlearium,
both produced in Escherichia coli, with either aquo- or cyanocobalamin. The
inactive glutamate mutase obtained was crystallized with polyethyleneglycol 4000
as precipitant. Crystals are monoclinic with space group P21 and have cell
dimensions a = 64.6, b = 113.2, c = 108.4 A and beta = 96.0 degrees for the
glutamate mutase reconstituted with aquocobalamin. They diffract to a resolution
of at least 2.7 A. Isolated component S was crystallized in the presence of an
excess of cyanocobalamin, yielding red crystals of space group I422 with unit
cell dimensions of a = b = 69.9 and c = 107.1 A. The crystals diffract to about
3.2 A resolution. Native data sets were collected for both crystal forms.
PMID- 9757133
TI - Cloning, overproduction, purification and crystallization of the DNA binding
protein HU from the hyperthermophilic eubacterium Thermotoga maritima.
AB - The humar gene encoding for the histone-like DNA-binding protein HU from the
hyperthermophilic eubacterium Thermotoga maritima was efficiently overexpressed
in Escherichia coli under the T7 promoter. The HU protein was purified using SP
Sepharose ion-exchange and heparin-affinity chromatography and was successfully
crystallized in ammonium sulfate. The crystals were grown in the tetragonal form
in space group P43 or P41 and have unit-cell dimensions a = b = 46.12, c = 77.56
A, alpha = beta = gamma = 90 degrees. The crystals diffract X-rays to 1.6 A
resolution using synchrotron radiation and are suitable for determination of the
HU structure at high resolution.
PMID- 9757134
TI - Expression, purification, crystallization and preliminary X-ray analysis of
cyclophilin A from the bovine parasite Trypanosoma brucei brucei.
AB - Cyclophilin A from the bovine parasite Trypanosoma brucei brucei has been cloned,
expressed in Escherichia coli, purified and crystallized in the presence of
cyclosporin A using ammonium sulfate as a precipitant. The crystals belong to the
orthorhombic crystal system with unit-cell dimensions of a = 118.61, b = 210.15
and c = 153.21 A. A data set complete to 2.7 A has been collected using rotating
anode radiation, however the crystals diffract to at least 2.1 A resolution using
synchrotron radiation.
PMID- 9757135
TI - Structure of pig plasma retinol-binding protein at 1.65 A resolution.
AB - The crystal structure of pig plasma retinol-binding protein (RBP) has been
determined at 1.65 A resolution. The space group is P212121, with a = 45.81 (4),
b = 53.14 (5), c = 72.97 (8) A and one protein molecule in the asymmetric unit.
The structure has been solved using the molecular replacement method and refined
with restrained least squares to an R factor of 0.1844 and an Rfree of 0.237 for
18 874 and 1001 independent reflections, respectively. The relatively high
resolution structure of pig holoRBP has revealed some new structural details.
Moreover, it has provided a description of the binding site for Cd2+, a metal ion
which is required for protein crystallization. The hepta-coordination of the RBP
bound cadmium ion involves different residues of two symmetry-related RBP
molecules, consistent with the participation of the cation in intermolecular
interactions that in turn promote protein crystallization.
PMID- 9757136
TI - Rapid X-ray diffraction analysis of HIV-1 protease-inhibitor complexes: inhibitor
exchange in single crystals of the bound enzyme.
AB - The ability to replace an inhibitor bound to the HIV-1 protease in single
crystals with other potent inhibitors offers the possibility of investigating a
series of protease inhibitors rapidly and conveniently with the use of X-ray
crystallography. This approach affords a fast turnaround of structural
information for iterative rational drug designs and obviates the need for
studying the complex structures by co-crystallization. The replacement approach
has been successfully used with single crystals of the HIV-1 protease complexed
with a weak inhibitor. The structures of the complexes obtained by the
replacement method are similar to those determined by co-crystallization.
PMID- 9757137
TI - Crystallization and preliminary X-ray studies of purine nucleoside phosphorylase
from Cellulomonas sp.
AB - The commercially available enzyme purine nucleoside phosphorylase (PNP) from
Cellulomonas sp. was purified by ion--exchange chromatography, partially
sequenced and crystallized in two different crystal forms using the hanging-drop
vapour-diffusion technique. Crystal form A grows as polyeders and/or cubes in the
cubic space group P4232 with unit-cell dimension a = 162.5 A. Crystal form B
appears as thick plates in the space group P212121 with unit-cell dimensions a =
63.2, b = 108.3 and c = 117.4 A. Both crystal forms contain three monomers (one
trimer) in the asymmetric unit.
PMID- 9757138
TI - Intra- and intercellular Ca2+ signaling in paraneurons and other secretory cells.
AB - Paraneurons are endocrine and sensory cells which share structural, functional,
and metabolic features with neurons. They produce identical with or related to
neurotransmitters or neurohormones, which are synthesized and secreted by
regulated secretion. They are receptoconductile-secretory in function, which is
shared by specific proteins distributed at proper regions of cell membrane. A
substantial advance has been made in the molecular machinery underlying protein
sorting and transport within the endoplasmic reticulum and Golgi apparatus, and
the mechanism of targeted membrane fusion by constitutive secretion. Various
patterns of [Ca2+]c dynamics play cardinal signaling roles in stimulus-secretion
coupling in individual secretory cells. Long-lived recurrent Ca2+ spikes or
oscillation may maintain prolonged secretory responses, ATP synthesis in
mitochondria, cell growth, differentiation, and division. In the neurons and the
paraneurons of neuroectodermal origin, action potentials propagate along a
conductile region to the secretory region of each cell and hardly be transmitted
to the adjacent cells. In the paraneurons of gut endodermal origin, intracellular
signalling including Ca2+ spikes can be propagated to the adjacent cells, and in
turn may maintain coordination of individual cells forming a cell society.
PMID- 9757139
TI - Adaptive changes in the capillary network in the left ventricle of rat heart.
AB - Capillaries are nonuniform thin tubes: The arteriolar and venular capillary
portions express alkaline phosphatase (AP) and dipeptidyl peptidase IV (DPPIV),
respectively. Differences in enzyme activities between arteriolar and venular
capillary portions could be shown by staining sections of cardiac tissues for AP
and DPPIV after coronary infusion of microspheres and by staining cultured
endothelial cells that had been collected from coronary microvessels. Through use
of a double staining method for AP and DPPIV, adaptive changes in the capillary
network were studied in rat hearts exposed to cold, exercise, hypertension,
chronic coronary occlusion, and transient coronary occlusion followed by
reperfusion. Two patterns could be seen in the adaptations of the ventricular
capillary network. The increase in the venular capillary portions is accompanied
by remarkable increases in capillary density and capillary-to-myocyte ratio. The
increase in the arteriolar capillary portion seemed to be accompanied by a
decrease or only a limited increase in capillary density in stressed hearts. The
increase in the total capillary density improves the capacity for oxygen
transport to tissues with a high tissue perfusion and a short diffusion distance
for oxygen. The increase in the arteriolar capillaries may also improve oxygen
transport by increasing the arterial blood perfusing the tissue. This seems,
however, a compensation for the limited angiogenesis: The alleviation of
stresses, such as pharmacological treatment of the hypertrophied heart and
reperfusion after transient ischemia, increases venular capillary portions and
capillary density. These changes are discussed with immunohistochemical
observations of rapid and prolonged expressions of angiogenic growth factors.
PMID- 9757140
TI - Impact of diffusional oxygen transport on oxidative metabolism in the heart.
AB - The resistance for the oxygen molecule to diffuse from the capillary blood to the
cell surface produces remarkably large gradients of oxygen partial pressure (PO2)
in the extracellular space. In addition, the intracellular radial gradients of
PO2 may not be ignored particularly when the cellular oxygen consumption is
increased. These PO2 gradients together result in a quite low intracellular PO2
in the cardiomyocyte in vivo. Thus, the cellular oxidative metabolism may be
limited by diffusional transport of oxygen from the capillary blood to
mitochondria. In this review, quantitative aspects and physiological relevances
of the PO2 gradient in the myocardium are discussed.
PMID- 9757141
TI - Immediate and sustained effects of smoking on autonomic arousal in human
subjects.
AB - The effects of smoking on sudomotor/autonomic activity were examined by measuring
water transfer across the skin (sweat output) as an index of activity. Sweat
output was measured in 14 subjects (11 male and 3 female) during the act of
smoking and for about 60 min following this. Sweat output was measured in 5 (4
male, 1 female) controls over the same time period. Smoking had two effects on
sweat output: In 12 subjects it caused an immediate increase in output; in 4 of
these 12 the increase persisted for the duration of the recording period. In the
other 2 subjects no increase was noted, but in no subject did smoking cause a
decrease in sweat output. Mood state questionnaires were administered at the
beginning and end of the experimental period. No clear association was found
between scores on the mood questionnaires and the autonomic effects of smoking.
In 2 subjects, transdermal blood flow was also measured during and after smoking.
Smoking caused a decrease in blood flow in these subjects. These results are
discussed in terms of the "arousal modulation" hypothesis of smoking.
PMID- 9757142
TI - Excitation of baroreceptors depresses A- and C-components of the somato-cardiac
sympathetic reflex in anesthetized rats.
AB - The effect of baroreceptor activation on somato-cardiac sympathetic reflex
discharges was examined in urethane-anesthetized, vagotomized, and artificially
ventilated rats. Single shock stimulation of myelinated (A) and unmyelinated (C)
fibers in the tibial nerve of the left hindlimb elicited two separate excitatory
reflex discharge components in a branch of the cardiac sympathetic nerve. They
are termed the A- and C-components of the somato-cardiac sympathetic reflex
discharges. When aortic nerves (AN) and carotid sinus nerves (CSN) were intact, a
sudden increase in mean arterial blood pressure to about 150 mmHg induced by I.V.
injection of phenylephrine (50 micro/kg) depressed the A- and C-components by up
to 47 +/- 5.4 and 37 +/- 7.7% of the control values, respectively. However,
bilateral sino-aortic denervation completely abolished the pressure-induced
depression of both components. We conclude that baroreceptor afferent signals
from the AN and CSN inhibit both A- and C-components of the excitatory somato
cardiac sympathetic reflex discharges. This and other previous evidence mentioned
in the text indicate that inhibitory cardiac sympathetic reflexes originating
from arterial baroreceptors and excitatory ones originating from somatic
afferents interact, probably at the brainstem.
PMID- 9757143
TI - Effect of posture change on control of ventilation.
AB - To clarify the control mechanism of ventilation during posture change,
ventilatory parameters, PETCO2, and ventilatory response to CO2 were examined in
11 healthy male subjects at supine (0 degrees) and 75 degrees head-up tilt
positions. Minute expiratory ventilation (V.E), tidal volume (VT), respiratory
frequency (f), end-tidal and transcutaneous PCO2 and CO2 output (V.CO2), and
ventilatory response to CO2 were measured during a steady state condition. V.E
(V.A) and VT increased significantly at 75 degrees tilt with significant decrease
in PETCO2 from 40.1 mmHg (0 degrees) to about 36.1 mmHg (75 degrees).
Transcutaneous PCO2 also decreased during tilt, by 3.3 mmHg. Physiological dead
space (VD/VT) and V.CO2, however, remained unchanged, and ventilatory equivalent
(V.E/V.CO2, V.A/V.CO2) increased significantly. The CO2-ventilatory response
curve shifted upward (or leftward) without significant change in the response
slope. At 75 degrees tilt, EMG activity of gastro-cnemius muscle increased. These
findings suggested that PETCO2 decreased because of increased V.E (V.A) with a
leftward shift of CO2-ventilatory response curve. Various signals such as
afferents from lower extremities might have net stimulatory effects on a CO2
ventilation control system to reset the controlled level of PETCO2 to a lower
range, but without significant change in CO2-ventilatory response during upright
position.
PMID- 9757144
TI - Involvement of NMDA and non-NMDA receptors in the neuronal responses of the
primary motor cortex to input from the supplementary motor area and somatosensory
cortex: studies of task-performing monkeys.
AB - The involvement of N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptors
in mediating the excitatory responses of neurons in the primary motor cortex (MI)
to electrical stimulation of the supplementary motor area (SMA) and the
somatosensory cortex (SI) was examined in monkeys performing a trained motor
task. During the task, a total of 109 MI neurons were identified and classified
as movement related (91), motor set related (7), or mixed (11). Subsequently, the
influence of receptor antagonists on the stimulus-evoked and task-related
activities of these neurons was examined. The selective NMDA antagonist D-2-amino
5-phosphonovaleric acid (APV) and the selective non-NMDA antagonist 6-cyano-7
nitroquinoxaline-2,3-dione (CNQX) were applied iontophoretically through
multibarreled micropipettes. One barrel was used for extracellular unit
recording. The excitatory response evoked by SI stimulation was suppressed by
CNQX in the vast majority (83%) of the motor task related neurons, and only 10%
were suppressed by APV. On the other hand, the response evoked by SMA stimulation
was suppressed by APV in 56% of the neurons and by CNQX in 54%. APV and CNQX had
parallel effects on the stimulus-evoked responses and the task-related neuronal
activity. These results indicate that NMDA and non-NMDA receptors are both
involved in mediating the excitatory responses of MI neurons to input from the
SMA and SI. On the other hand, the data suggest a greater contribution of non
NMDA receptors in response to SI input and greater involvement of NMDA receptors
in mediating the response to SMA input, especially among set-related MI neurons.
PMID- 9757145
TI - Influence of sustained hypoxia on the sensation of dyspnea.
AB - We assessed the effect of sustained isocapnic hypoxia (PCO2 = 40 Torr, SaO2 =
80%) on the sensation of dyspnea in 16 normal healthy males. Subjects rated the
sensation of dyspnea (c) on 15 cm visual analog scales during 20 min of sustained
hypoxia. Following this hypoxic period, 8 subjects undertook mild exercise (10-50
W on a bicycle ergometer for 3 min) under the continuation of hypoxia. During
sustained hypoxia, psi increased initially with ventilation from 0.6 +/- 0.2 (n =
16, mean +/- SE) to 2.9 +/- 0.6 at peak ventilation, but it decreased with
ventilatory depression to 1.6 +/- 0.4. Dyspnea intensity during hypoxic exercise
was significantly smaller than that at peak ventilation in the resting hypoxic
period (2.3 +/- 0.7 vs. 3.9 +/- 1.0), although the ventilation was greater during
exercise (24.0 +/- 3.0 vs. 19.7 +/- 1.4 l/min). These results indicate that
sustained hypoxia has a biphasic, i.e., initial stimulatory and delayed
depressant, effect on dyspnea and on ventilation. It is suggested that the
dyspnea sensing mechanism is suppressed during mild exercise under sustained
hypoxia.
PMID- 9757146
TI - Repetitive mechanical responses of the amphibian skin to adrenergic stimulation .
AB - Mechanical responses of the amphibian nerve-skin preparation to adrenergic
stimulation were investigated by recording pressure changes at the skin surface
with a piezoelectric sensor. When a dilute epinephrine (or norepinephrine)
solution was applied to the inner skin surface, repetitive mechanical responses,
representing quick swelling of the skin repeating at more or less regular
intervals of about 1 min, were frequently observed. In about 10% of the
preparations, the skin was found to undergo repetitive quick shrinkage (instead
of swelling) under practically indistinguishable experimental conditions. Rapid
volume changes occurring in the cytoplasmic gel of the gland cells are considered
to be at the base of these repetitive mechanical responses.
PMID- 9757147
TI - Ketoconazole inhibition of triazolam and alprazolam clearance: differential
kinetic and dynamic consequences.
AB - BACKGROUND: Kinetic and dynamic consequences of metabolic inhibition were
evaluated in a study of the interaction of ketoconazole, a P4503A inhibitor, with
alprazolam and triazolam, two 3A substrate drugs with different kinetic profiles.
METHODS: In a double-blind, 5-way crossover study, healthy volunteers received
(A) ketoconazole placebo plus 1.0 mg alprazolam orally, (B) 200 mg ketoconazole
twice a day plus 1.0 mg alprazolam, (C) ketoconazole placebo plus 0.25 mg
triazolam orally, (D) 200 mg ketoconazole twice a day plus 0.25 mg triazolam, and
(E) 200 mg ketoconazole twice a day plus benzodiazepine placebo. Plasma
concentrations and pharmacodynamic parameters were measured after each dose.
RESULTS: For trial B versus trial A, alprazolam clearance was reduced (27 versus
86 mL/min; P < .002) and apparent elimination half-life (t1/2) prolonged (59
versus 15 hours; P < .03), whereas peak plasma concentration (Cmax) was only
slightly increased (16.1 versus 14.7 ng/mL). The 8-hour pharmacodynamic effect
areas for electroencephalographic (EEG) beta activity were increased by a factor
of 1.35, and those for digit-symbol substitution test (DSST) decrement were
increased by 2.29 for trial B versus trial A. For trial D versus trial C,
triazolam clearance was reduced (40 versus 444 mL/min; P < .002), t1/2 was
prolonged (18.3 versus 3.0 hours; P < .01), and Cmax was increased (2.6 versus
5.4 ng/mL; P < .001). The 8-hour effect area for EEG was increased by a factor of
2.51, and that for DSST decrement was increased by 4.33. Observed in vivo
clearance decrements due to ketoconazole were consistent with those anticipated
on the basis of an in vitro model, together with in vivo plasma concentrations of
ketoconazole. CONCLUSION: For triazolam, an intermediate-extraction compound,
impaired clearance by ketoconazole has more profound clinical consequences than
those for alprazolam, a low extraction compound.
PMID- 9757148
TI - Grapefruit juice-felodipine interaction: effect of naringin and 6',7'
dihydroxybergamottin in humans.
AB - OBJECTIVE: To test whether naringin or 6',7'-dihydroxybergamottin is a major
active substance in grapefruit juice-felodipine interaction in humans. METHODS:
Grapefruit juice was separated by means of centrifugation and filtration into
supernatant and particulate fractions, which were then assayed for naringin and
6',7'-dihydroxybergamottin. The effect of these fractions, grapefruit juice
(containing comparable amounts of both fractions), and water on the
pharmacokinetics of oral felodipine were assessed in 12 healthy men in a
randomized, 4-way crossover study. RESULTS: The amounts of naringin and 6',7'
dihydroxybergamottin in the supernatant fraction (148 mg and 1.85 mg) were
greater than in the particulate fraction (7 mg and 0.60 mg). The area under the
plasma concentration-time curve (AUC) and the peak concentration (Cmax) of
felodipine were higher with supernatant fraction (81 nmol.h/L and 20 nmol/L),
particulate fraction (117 nmol.h/L and 24 nmol/L), and grapefruit juice (130
nmol.h/L and 33 nmol/L) compared with water (53 nmol.h/L and 11 nmol/L). However,
the supernatant fraction had a lower AUC for felodipine and a similar Cmax of
felodipine relative to the particulate fraction. The supernatant fraction neither
augmented the AUC of the primary metabolite dehydrofelodipine nor decreased the
AUC ratio of dehydrofelodipine to felodipine compared with water. Individually
the supernatant fraction consistently produced lower felodipine AUC and Cmax
compared with grapefruit juice. In contrast, the particulate fraction had values
ranging from more than grapefruit juice to less than supernatant fraction.
CONCLUSIONS: Naringin and 6',7'-dihydroxybergamottin are not the major active
ingredients, although they may contribute to the grapefruit juice-felodipine
interaction. The variable effect with the particulate fraction may result from
erratic bioavailability of unidentified primary active substances. The findings
show the importance of in vivo testing to determine the ingredients in grapefruit
juice responsible for inhibition of cytochrome P450 3A4 in humans.
PMID- 9757149
TI - Effect of fluvoxamine therapy on the activities of CYP1A2, CYP2D6, and CYP3A as
determined by phenotyping.
AB - OBJECTIVE: To determine the effect of 150 mg/day fluvoxamine on the activities of
CYP1A2, CYP2D6, CYP3A, N-acetyltransferase-2 (NAT2), and xanthine oxidase (XO) by
phenotyping with caffeine, dextromethorphan, and midazolam. METHODS: Oral
caffeine (2 mg/kg), oral dextromethorphan (30 mg), and intravenous midazolam
(0.025 mg/kg) were administered to 10 white male volunteers every 14 days for 4
months and to 10 white premenopausal female volunteers during the midfollicular
and midluteal phases of the menstrual cycle for 4 complete cycles (8 total
phenotyping measures). The first 6 phenotyping measures were used to establish
baseline activity. Subjects were given 150 mg/day fluvoxamine for the fourth
month or cycle of the study. Enzyme activity for CYP1A2, CYP2D6, NAT2, and XO was
expressed as urinary metabolite ratios. Midazolam plasma clearance was used to
express CYP3A activity. RESULTS: No difference between baseline and weeks 2 and 4
of fluvoxamine therapy was observed for NAT2 or XO metabolite ratios. For CYP1A2,
CYP2D6, and CYP3A phenotypes, significant differences existed between baseline
and fluvoxamine therapy. For CYP1A2, the mean urinary metabolite ratio (+/-SD)
was 7.53 +/- 7.44 at baseline and 4.30 +/- 2.82 with fluvoxamine ( P = .012).
Mean CYP2D6 molar urinary dextromethorphan ratios before and after fluvoxamine
therapy were 0.00780 +/- 0.00694 and 0.0153 +/- 0.0127, respectively (P = .011).
Midazolam clearance decreased from 0.0081 +/ 0.0024 L/min/kg at baseline to
0.0054 +/- 0.0021 L/min/kg with therapy (P = .0091). For CYP1A2, CYP2D6, and
CYP3A, fluvoxamine therapy changed the phenotyping measures by a median of
44.4%, 123.5%, and -34.4%, respectively. CONCLUSIONS: We concluded that
fluvoxamine may cause significant inhibition of CYP1A2, CYP2D6, and CYP3A
activity. This metabolic inhibition may have serious implications for a variety
medications.
PMID- 9757150
TI - Quantification of 3-month intraindividual variability and the influence of sex
and menstrual cycle phase on CYP3A activity as measured by phenotyping with
intravenous midazolam.
AB - OBJECTIVE: Intraindividual variability and the effects of sex and menstrual cycle
phase on CYP3A activity were evaluated by phenotyping with use of midazolam as
the probe drug. METHODS: Midazolam (0.025 mg/kg) was administered intravenously
to 10 white male volunteers every 14 days for 3 months and to 10 white
premenopausal female volunteers during the midfollicular and midluteal phases of
the menstrual cycle for 3 complete cycles. Serum was collected for a 6-hour
period, and enzyme activity was represented by midazolam plasma clearance.
RESULTS: No difference in clearance was observed during the menstrual cycle
phases. Mean +/- SD midazolam clearance was 0.00816 +/- 0.00252 L/min/kg during
the midfollicular phase and 0.00818 +/- 0.00224 during the midluteal phase (P =
.96). When the menstrual cycle phases were combined, mean midazolam clearance in
women was 0.00817 +/- 0.00235 L/min/kg. Mean male midazolam clearance was 0.00766
+/ 0.00167 L/min/kg. There was no difference in midazolam clearance between men
and women (P = .68). Coefficients of variation (CV%) for the 6 phenotyping visits
were calculated and the median midazolam clearance CV% (25th to 75th percentile)
was 9.75% (8.40% to 11.5%). CONCLUSIONS: Because no significant differences in
midazolam clearance were noted between menstrual cycle phases or between sexes,
pharmacokinetic and clinical investigations of CYP3A activity in adults may not
require stratification on the basis of menstrual cycle phase or sex.
PMID- 9757152
TI - Effect of grapefruit juice on carbamazepine bioavailability in patients with
epilepsy.
AB - OBJECTIVE: To examine the effect of grapefruit juice on the bioavailability of
carbamazepine in patients with epilepsy. METHODS: This was a randomized crossover
study consisting of 2 phases. Ten patients with epilepsy who had received therapy
with 200 mg carbamazepine 3 times a day for the previous 3 to 4 weeks
participated. They were given either grapefruit juice or 300 mL water at 8 am
along with 200 mg carbamazepine. Each treatment was separated by 2 days; subjects
continued to receive carbamazepine therapy during the 2-day period. On both
occasions, blood samples were collected at different time intervals between 0 to
8 hours. Carbamazepine levels were estimated by reversed-phase HPLC technique.
RESULTS: Compared with water, grapefruit significantly increased the steady peak
concentration (6.55 versus 9.20 microgram/mL), trough concentration (4.51 versus
6.28 microgram/mL), and area under the plasma concentration-time curve (43.99
versus 61.95 micrograms.h/mL) of carbamazepine. No significant effect was found
in the time to reach peak plasma concentration. CONCLUSION: Grapefruit juice
increases the bioavailability of carbamazepine by inhibiting CYP3A4 enzymes in
gut wall and in the liver.
PMID- 9757151
TI - Inhibition of triazolam clearance by macrolide antimicrobial agents: in vitro
correlates and dynamic consequences.
AB - BACKGROUND: Macrolide antimicrobial agents may impair hepatic clearance of drugs
metabolized by cytochrome P4503A isoforms. Potential interactions of triazolam, a
substrate metabolized almost entirely by cytochrome P4503A in humans, with 3
commonly prescribed macrolides were identified using an in vitro metabolic model.
The actual interactions, and their pharmacodynamic consequences, were verified in
a controlled clinical study. METHODS: In an in vitro model using human liver
microsomes, 250 mumol/L triazolam was incubated with ascending concentrations (0
to 250 mumol/L of troleandomycin, azithromycin, erythromycin, and clarithromycin.
In a randomized, double-blind, 5-trial clinical pharmacokinetic-pharmacodynamic
study, 12 volunteers received 0.125 mg triazolam orally, together with placebo,
azithromycin, erythromycin, or clarithromycin. In a fifth trial they received
placebo plus placebo. RESULTS: Mean 50% inhibitory concentrations versus 4
hydroxytriazolam formation in vitro were as follows: 3.3 mumol/L troleandomycin,
27.3 mumol/L erythromycin, 25.2 mumol/L clarithromycin, and greater than 250
mumol/L azithromycin. Apparent oral clearance of triazolam when given with
placebo or azithromycin was nearly identical (413 and 416 mL/min), as were peak
plasma concentrations (1.25 and 1.32 ng/mL) and elimination half-life (2.7 and
2.6 hours). Apparent oral clearance was significantly reduced (P < .05) during
erythromycin and clarithromycin trials (146 and 95 mL/min). Peak plasma
concentration was correspondingly increased, and elimination half-life was
prolonged. The effects of triazolam on dynamic measures were nearly identical
when triazolam was given with placebo or azithromycin, but benzodiazepine agonist
effects were enhanced during erythromycin and clarithromycin trials. CONCLUSION:
The in vitro model identifies macrolides that may impair triazolam clearance.
Anticipated interactions, and their pharmacodynamic consequences in volunteer
subjects, were verified in vivo.
PMID- 9757153
TI - Pharmacokinetics of cyclophosphamide and its metabolites in bone marrow
transplantation patients.
AB - OBJECTIVES: To characterize the pharmacokinetics of cyclophosphamide and 5 of its
metabolites in bone marrow transplant patients and to identify the mechanism of
the increase in 4-hydroxycyclophosphamide area under the plasma concentration
time curve (AUC) from day 1 to day 2 of cyclophosphamide administration. METHODS:
Cyclophosphamide was administered by intravenous infusion (60 mg/kg over 1 hour,
once a day) for 2 consecutive days to 18 patients. Cyclophosphamide and 4
hydroxycyclophosphamide concentration time data on day 1 and day 2 were fitted to
a model to estimate 4-hydroxycyclophosphamide formation (CLf) and elimination
(CLm) clearances. Erythrocyte aldehyde dehydrogenase-1 activity was measured ex
vivo just before the first cyclophosphamide infusion was started (0 hours) and 24
hours after the second cyclophosphamide infusion (48 hours). RESULTS: From day 1
to day 2, the AUC of cyclophosphamide, deschloroethyl cyclophosphamide and
phosphoramide mustard decreased 24.8%, 51%, and 29.4% (P < .02), the AUC of 4
hydroxycyclophosphamide and carboxyethylphosphoramide mustard increased 54.7% and
25% (P < .01), whereas the AUC of phosphoramide mustard was not significantly
changed (P > .3). The CLf of 4-hydroxycyclophosphamide increased 60% (P < .001),
its CLm decreased 27.7% (P < .001), and the fraction of cyclophosphamide dose
converted to 4-hydroxycyclophosphamide increased 16% (P < .001) from day 1 to day
2. The activity of patient erythrocyte aldehyde dehydrogenase-1 decreased 23.3%
(P < .02) from 0 hours to 48 hours. CONCLUSIONS: The AUC of 4
hydroxycyclophosphamide increased from day 1 to day 2 as a result of increased
formation and decreased elimination clearances of 4-hydroxycyclophosphamide.
Aldehyde dehydrogenase-1 activity appears to decline as a consequence of
cyclophosphamide administration.
PMID- 9757154
TI - Amiodarone causes endothelium-dependent vasodilation in human hand veins in vivo.
AB - OBJECTIVE: Amiodarone, a class III antiarrhythmic agent, is a potent coronary
vasodilator. However, direct evidence for its vasodilatory effects in human
vasculature in vivo is not available. The aim of the study was to investigate the
short-term effects of amiodarone in preconstricted human hand veins and to
explore the underlying mechanisms. METHODS: Thirty-one healthy male volunteers
were studied with the use of the dorsal hand vein compliance technique. The hand
veins of the subjects were preconstricted with the alpha 1-adrenergic receptor
agonist phenylephrine, and amiodarone, inhibitors of nitric oxide formation (NG
monomethyl-L-arginine, L-NMMA), and adenosine triphosphate-dependent potassium
channels (glyburide [INN, glibenclamide]) were infused in the presence or absence
of a cyclooxygenase inhibitor (acetylsalicylic acid), and the venodilator effect
was measured. Furthermore, amiodarone was infused in prostaglandin F2 alpha
(dinoprost)-preconstricted hand veins. RESULTS: Amiodarone produced dose
dependent venodilation (51% +/- 3% maximum). Maximum amiodarone-induced
venodilation was lower in dinoprost compared with phenylephrine-preconstricted
veins. Pretreatment with acetylsalicylic acid reduced the amiodarone-induced
venodilation by 40% +/- 6%. L-NMMA reduced the amiodarone-induced venodilation
after pretreatment with acetylsalicylic acid by 72% +/- 3%. Glyburide decreased
the venodilatory response of amiodarone by 31% +/- 11%, whereas only a slight but
not statistically significant additional reduction in venodilation was detected
after pretreatment with acetylsalicylic acid. Infusion of the solvents of
commercially available amiodarone (polysorbate 80 and benzyl alcohol) did not
cause vasodilation in phenylephrine-preconstricted veins. CONCLUSIONS: Amiodarone
dilates preconstricted human hand veins in vivo and acts as a venodilator through
the cyclooxygenase pathway, activation of nitric oxide synthase, and blockade of
alpha adrenergic mechanisms.
PMID- 9757155
TI - Dynamic analysis of dofetilide-induced changes in ventricular repolarization.
AB - OBJECTIVE: To use dynamic electrocardiographic (ECG) techniques to study the
influence of heart rate on dofetilide-induced QT prolongation among healthy
volunteers. BACKGROUND: The extent to which heart rate modulates QT prolongation
induced by the new class III antiarrhythmic drug dofetilide is a matter of
debate. METHODS: Ten healthy volunteers underwent two 24-hour ECG recordings, one
in the absence of dofetilide and the other after a single oral dose of 0.5 mg
dofetilide. Two 4-hour periods were defined during the second recording: Dh,
which corresponded to stable high concentration of the drug, and D1, which
corresponded to low concentration of the drug. Corresponding baseline recording
periods, Ch and C1, matched by time with Dh and D1 were selected from the control
ECG recording in the absence of dofetilide. QT versus R-R relations were compared
in the presence and absence of dofetilide. The QT versus R-R relation slope was
used as an index of the rate dependence QT prolongation. Rate-independent changes
in QT duration were also analyzed. RESULTS: During Dh, dofetilide induced a mean
12% lengthening of ventricular repolarization. Dynamic ECG analysis showed that
this prolongation increased as R-R cycles became longer, a phenomenon known as
reverse rate dependence. However, QT prolongation persisted at the shortest (600
ms) R-R cycle length that could be analyzed. During D1, dynamic ECG analysis
showed a persistent, although small, effect of dofetilide on both QT prolongation
(3%) and reverse rate dependence of this effect. CONCLUSIONS: Dofetilide prolongs
QT duration, and this class III effect is influenced by heart rate. Although
dofetilide-induced QT prolongation decreases when the R-R cycle shortens, this
reverse rate dependence is only partial because marked QT prolongation persists
at an R-R cycle of 600 ms. The results of our study indicated that dynamic ECG
techniques can be useful in detection of subtle, drug-induced changes in the
duration of ventricular repolarization.
PMID- 9757156
TI - Hemodynamic effects of continuous urodilatin infusion: a dose-finding study.
AB - OBJECTIVE: To evaluate the effects of urodilatin (INN, ularitide) on systemic and
renal hemodynamic parameters. METHODS: Twenty healthy male subjects were included
in this double-blind, randomized placebo-controlled trial and assigned to receive
either continuous intravenous infusion of different doses of 7.5, 15, or 22.5
ng/kg body weight/min urodilatin or placebo over 300 minutes. Cardiac
performance, systolic time intervals, and airway function were measured
noninvasively. The effects on renal hemodynamic values were assessed with para
aminohippurate and inulin clearance techniques. RESULTS: Urodilatin was well
tolerated by all subjects at doses of 7.5 and 15 ng/kg/min. Infusion was stopped
prematurely for the group that received 22.5 ng/kg/min urodilatin group because
of systemic hypotensive responses with nausea and dizziness. Infusion of 15
ng/kg/min urodilatin significantly increased urine flow by a maximum of 165%,
filtration fraction by 46%, renal resistance by 49%, and systemic vascular
resistance by 45%. It decreased renal plasma flow by a maximum of 31% from
baseline value. No change in cardiac inotropic function was detectable, but
cardiac output decreased in all dose groups. Effects on glomerular filtration
rate, forced expiratory volume, blood pressure, and pulse were not different from
those with placebo. CONCLUSION: Continuous infusion of 7.5 ng/kg/min and 15
ng/kg/min urodilatin exerts a significant increase in systemic and renal vascular
resistance. Results of our experiments suggested that the therapeutic window for
continuous urodilatin infusion is small and that doses higher than approximately
20 ng/kg/min urodilatin carry high risk for adverse drug reactions.
PMID- 9757157
TI - Concentration-controlled zidovudine therapy.
AB - BACKGROUND: Heterogeneity in the response to antiretroviral therapy has been
attributed to pharmacologic, immunologic, and virologic differences between
patients. Currently available antiretroviral agents used for the treatment of
human immunodeficiency virus (HIV) infection in adults are administered in
standard fixed doses. The active moiety of nucleoside anti-HIV drugs is the
intracellular anabolite. Therefore the heterogeneity in response to nucleoside
agents may arise as a result of pharmacologic variability at both the systemic
and cellular level. OBJECTIVES: To determine whether a novel concentration
controlled zidovudine regimen could improve anti-HIV response compared with the
standard fixed-dose approach. DESIGN: At the Outpatient Clinic of the General
Clinical Research Center at the University of Minnesota, 20 persons with HIV
infection received an oral regimen of zidovudine designed to achieve a target
concentration in plasma of 0.7 mumol/L and the 500 mg/day standard dose in a
randomized, crossover 24-week study. RESULTS: The concentration-controlled
regimen achieved overall higher systemic concentrations with reduced interpatient
variability: steady-state average zidovudine plasma concentrations were 0.76
mumol/L (coefficient of variation, 12%) versus 0.62 mumol/L (coefficient of
variation, 32%) for the standard regimen. There was no difference in safety and
tolerance between regimens. Intracellular zidovudine triphosphate concentrations
averaged 160 fmol/10(6) peripheral blood mononuclear cells (PBMCs) with
concentration-controlled versus 92 fmol/10(6) PBMCs for standard therapy. The
percentage change from baseline in CD4 cells was a 22% increase for the
concentration-controlled regimen versus a 7% decrease with standard therapy.
CONCLUSIONS: These data indicate that pharmacologic variability affects
antiretroviral response. Furthermore, these findings provide a framework to
characterize the pharmacologic determinants of effect and quantitate their
contribution to the heterogeneity in clinical response to optimize therapeutic
benefit.
PMID- 9757158
TI - Phase I study of a humanized anti-CD11/CD18 monoclonal antibody in multiple
sclerosis.
AB - OBJECTIVE: To evaluate the safety, pharmacokinetics, pharmacodynamics, and
immunogenicity of a humanized anti-CD11/CD18 monoclonal antibody (Hu23F2G) in
patients with multiple sclerosis. METHODS: In this phase I uncontrolled dose
escalation study, patients (n = 24) with primary or secondary progressive
multiple sclerosis received single intravenous infusions of Hu23F2G (0.01 to 4.0
mg/kg). Study parameters included safety, pharmacology, immunogenicity, and brain
magnetic resonance imaging (MRI). RESULTS: Hu23F2G had few adverse effects, but 2
cases of urinary tract infection and 2 cases of gingivitis did occur. Transient
leukocytes developed in some subjects receiving > or = 1.0 mg/kg. The
pharmacokinetic response was nonlinear, with the area under the curve increasing
out of proportion to the increase in dose. The mean terminal half-life increased
with dose and was 21.9 (SD, 12.8) hours at the 4.0 mg/kg dose. High saturation (>
80%) of CD11/CD18 on circulating leukocytes was achieved with doses > or = 0.2
mg/kg. The duration of high leukocyte saturation was dose-dependent, persisting
for more than a week at the 4.0 mg/kg dose. A marked decrease in leukocyte
migration in response to cutaneous inflammation was observed. Antibodies against
Hu23F2G were not detected. The neurologic examinations were stable except for 1
subject who had worsening weakness associated with an infection. No significant
changes were noted on brain MRI scans. CONCLUSIONS: Hu23F2G was tolerated at
doses that achieved high degrees of leukocyte CD11/CD118 saturation with in vivo
inhibition of leukocyte migration. Because this phase I study was not designed to
determine the clinical efficacy of Hu23F2G, further studies are needed.
PMID- 9757159
TI - Buspirone plasma concentrations.
PMID- 9757160
TI - Carcinogen-in-a-can.
PMID- 9757161
TI - Secondhand smoke and cancer: Where's the proof?
PMID- 9757162
TI - Evidence for effectiveness of home care.
PMID- 9757163
TI - Confidentiality in medical publishing.
PMID- 9757164
TI - Facing reality.
PMID- 9757165
TI - Marathon's success.
PMID- 9757166
TI - Understanding Quebec's policy on nursing training.
PMID- 9757167
TI - National incidence study of child abuse and neglect.
PMID- 9757168
TI - Recent findings from the Ontario Student Drug Use Survey.
AB - BACKGROUND: Every 2 years, the Addiction Research Foundation of Ontario, a
division of the Centre for Addiction and Mental Health, sponsors the Ontario
Student Drug Use Survey. The results of the surveys conducted in 1995 and 1997
are presented here and compared with results from the early 1990s. METHODS:
Questionnaires were completed by 3870 and 3990 Ontario public school students
enrolled in grades 7, 9, 11 and 13 in 1995 and 1997 respectively. The outcome
measures were prevalence of use of 20 types of drugs and other substances,
including alcohol, tobacco and prescription drugs, over the previous 12 months.
RESULTS: For several drugs the prevalence of use in the previous 12 months had
increased from 1993 to 1995, but from 1995 to 1997 there was a significant
increase for only one type (hallucinogens such as mescaline and psilocybin). The
inhalation of glue declined, and the use of the other 18 types of drugs remained
stable. INTERPRETATION: Recent data suggest that increases in adolescent student
drug use reported earlier this decade have not continued. However, the stability
in rates of drug use is not a justification for complacency in this important
area of public health.
PMID- 9757169
TI - Relation between severity of Alzheimer's disease and costs of caring.
AB - BACKGROUND: Data from the Canadian Study of Health and Aging (CSHA) were used to
examine the relation between severity of Alzheimer's disease, as measured by the
Mini-Mental State Examination (MMSE), and costs of caring. METHODS: The CSHA was
a community-based survey of the prevalence of dementia, including subtypes such
as Alzheimer's disease, among elderly Canadians. Survey subjects with a diagnosis
of possible or probable Alzheimer's disease were grouped into disease severity
levels of mild (MMSE score 21-26), mild to moderate (MMSE score 15-20), moderate
(MMSE score 10-14) and severe (MMSE score below 10). Components of care available
from the CSHA were use of nursing home care, use of medications, use of community
support services by caregivers and unpaid caregiver time. Costs were calculated
from a societal perspective and are expressed in 1996 Canadian dollars. RESULTS:
The annual societal cost of care per patient increased significantly with
severity of Alzheimer's disease. The cost per patient was estimated to be $9451
for mild disease, $16,054 for mild to moderate disease, $25,724 for moderate
disease and $36,794 for severe disease. Institutionalization was the largest
component of cost, accounting for as much as 84% of the cost for people with
severe disease. For subjects living in the community, unpaid caregiver time and
use of community services were the greatest components of cost and increased with
disease severity. INTERPRETATION: The societal cost of care of Alzheimer's
disease increases drastically with increasing disease severity.
Institutionalization is responsible for the largest cost component.
PMID- 9757171
TI - Secrecy and the health protection branch.
PMID- 9757170
TI - The antihypertensive efficacy of losartan and amlodipine assessed with office and
ambulatory blood pressure monitoring. Canadian Cozaar Hyzaar Amlodipine Trial
Study Group.
AB - BACKGROUND: Losartan potassium is a recently marketed angiotensin II receptor
antagonist. Previous studies have suggested that its full antihypertensive
efficacy may be delayed for up to 12 weeks. The authors compared the
antihypertensive efficacy and tolerability of losartan at 6 and 12 weeks with
those of amlodipine besylate, a commonly used calcium antagonist. METHODS: This
multicentre, randomized, double-blind clinical trial studied 302 patients with
mild or moderate hypertension in 1995. Of the 302, 97 also underwent ambulatory
blood pressure monitoring (ABPM). After a 4-week placebo run-in period, the
patients were randomly assigned to group A, B or C for 12 weeks. Those in groups
A and B began treatment with losartan at 50mg/d, and those in group C began with
amlodipine at 5 mg/d. If the blood pressure remained uncontrolled after 6 weeks,
subjects in group A had their losartan dose doubled (to 100 mg/d), those in group
B were given hydrochlorothiazide (12.5 mg/d) in addition to the losartan, which
remained at 50 mg/d, and patients in group C had their amlodipine dose doubled
(to 10 mg/d). RESULTS: At 12 weeks all 3 regimens reduced office-recorded
diastolic blood pressure (DBP) with the patient sitting. The mean reduction in
group A was 8.7 mm Hg (95% confidence interval [CI] 7.3 to 10.1) (p < 0.001), in
group B 12.5 mm Hg (95% CI 11.0 to 14.0) (p < 0.001) and in group C 12.9 mm Hg
(95% CI 11.4 to 14.5) (p < 0.001). Losartan alone lowered sitting DBP to a lesser
degree than the other 2 treatments (p < 0.01). In contrast, ABPM readings,
whether 24-hour, daytime or nighttime, were not different among the regimens.
Comparison of the results at 6 weeks yielded similar findings. Adverse effects
were uncommon and were not different among the groups, with the exception of
ankle edema, which was more frequent in group C. INTERPRETATION: Losartan alone
reduces both office and ABPM readings. The observed changes in office-recorded
sitting DBP suggest that losartan is less effective than amlodipine or the
combination of losartan and hydrochlorothiazide, but ABPM did not confirm this
difference. Perhaps changes in office readings measure different attributes of a
drug than does ABPM.
PMID- 9757172
TI - A time for everything: changing attitudes and approaches to reducing substance
abuse.
PMID- 9757173
TI - Randomized clinical trials of antihypertensive drugs: all that glitters is not
gold.
PMID- 9757174
TI - Prostate cancer: progress and perplexity.
PMID- 9757175
TI - Funding Canada's health care system: a tax-based alternative to privatization.
PMID- 9757176
TI - Still here, still flawed, still wrong: the case against the case for taxing the
sick.
PMID- 9757177
TI - Patient consent for publication--an apology.
PMID- 9757178
TI - Prostate cancer: 1. The descriptive epidemiology in Canada.
AB - A 70-year-old woman who experienced a long period of depression after her first
husband's death from prostate cancer at the age of 63 has become increasingly
anxious about her own health and that of her close family. A few years ago she
married a man her own age; he is in good physical condition. Last year the family
spent much of the winter in Florida, where the woman noticed several studies in
the media suggesting that an epidemic of prostate cancer is occurring in North
America and that because early detection can save lives men of retirement age
should be checked by their physicians as soon as possible. In addition, 2 close
friends recently diagnosed with prostate cancer. On his latest fishing trip her
husband learned from a friend that 1 in 8 men get prostate cancer. He has not
seen his family physician for several years, but his wife has booked an
appointment for them to discuss their concerns.
PMID- 9757179
TI - Ascending the magic mountain.
PMID- 9757180
TI - Chronic fatigue syndrome or just plain tired?
PMID- 9757181
TI - Anemic loonie begins to affect health care sector.
AB - Although most news surrounding the declining dollar has concentrated on its
impact on Canadian shoppers, economists say it is bound to affect the financially
strapped health care system too. They point out that many of the good purchased
by Canadian hospitals come from the US, and the weak loonie means their price
will rise.
PMID- 9757182
TI - Results from CMA's huge 1998 physician survey point to a dispirited profession.
AB - Results from the CMA's 1998 Physician Resource Questionnaire are in, and they
point to a serious decline in physician morale. The PRQ, the country's most
important poll of physician attitudes, provides an annual "state-of-the-nation"
message for the medical profession.
PMID- 9757183
TI - Chronic fatigue syndrome get court's nod of approval as legitimate disorder.
AB - Lawyer Karen Capen looks at the implications of a recent Alberta court case
involving chronic fatigue syndrome. She thinks Canada's physicians should pay
close attention to this precedent-setting case.
PMID- 9757184
TI - Chronic fatigue syndrome comes out of the closet.
AB - An Alberta court ruling and new guidelines for physicians issued by the Quebec
medical college are giving chronic fatigue syndrome a legitimacy it never before
enjoyed. What will this mean for physicians?
PMID- 9757185
TI - Offshore energy boom providing opportunities outside Medicare's umbrella.
AB - Physicians upset by limits imposed by the medicare system are getting a chance to
spread their entrepreneurial wings on the East Coast. A boom in offshore
exploration, led by Newfoundland's massive Hibernia project, has led to numerous
business opportunities for physicians.
PMID- 9757186
TI - New private facility woos public dollars in Calgary.
AB - The opening of a private wing in an old hospital has caused consternation in
Calgary because some people consider it a beachhead for private medicine.
PMID- 9757187
TI - [Meta-analysis of clinical trials for chemotherapy in cancer].
AB - Meta-analysis has attracted great interest among clinical practitioners in recent
years, leading to a steady output of related publications. Meta-analytic articles
are easily found in the MEDLINE database using the publication-type option. This
paper reviews how to use and understand meta-analysis with a special reference to
chemotherapy applied to cancer patients. It is described in relationship to
evidence-based medicine (EBM) and clinical practice guidelines. Cochrane
collaboration is also referred to as an active voluntary organization conducting
meta-analysis. In the technical sections, statistical issues and graphic
representations are clearly illustrated using the example of hepatic arterial
infusion for colorectal cancer patients. The difference between fixed and random
effects models is briefly explained. Finally, an example from Cochrane Library,
namely progestagen therapy for endometrial cancer, is illustrated to show the
implications of meta-analysis for clinical practice.
PMID- 9757188
TI - [Controversy on treatments for gliomas].
AB - Gliomas are representative primary malignant brain tumors, and with such tumors
it is difficult to define the advanced stage. If the advanced stage indicates no
curability by surgery alone, most gliomas would belong to this criterion because
of their poor prognosis without any completely effective treatment. In this
sense, no one could show a standard therapy to treat these unfortunate patients,
for example, patients with glioblastoma, they could permit only 1 year survived
even they had any applicable treatments to the lesions, these days. Treatment for
low-grade gliomas has been most controversial for a long time, and no standard
treatments have been determined so far. In this paper, as the treatment of low
grade gliomas it was intended to report what must be done for this patient and
the present results of opinion survey for the treatment of gliomas which was done
to professors of 80 institutes, from schools of medicine at all universities and
medical colleges in Japan. For high-grade gliomas, some effectiveness of
radiation therapy was disclosed as well as chemotherapy from recent papers. Gene
therapy was also discussed briefly, its present status and future.
PMID- 9757189
TI - [Recent treatment modality for advanced head and neck carcinomas].
AB - Histopathologically, about 90% of head and neck cancer is squamous cell
carcinoma. The curative treatments for head and neck cancer are conventional
radiotherapy and/or surgical resection. Multidisciplinary treatment, including
combinations of the curative therapy, chemotherapy and immunotherapy, has been
applied for advanced head and neck carcinomas with poor outcomes. Nowadays,
chemotherapy is under investigation in the neo-adjuvant, adjuvant and concurrent
chemoradiotherapy. In this paper, the treatment approach was reviewed in terms of
prognostic factors which have been retrospectively estimated, along with recent
developments in treatment modalities of advanced cases.
PMID- 9757190
TI - [Recent issue in the treatment of small-cell lung cancer].
AB - Chemotherapy is currently a primary treatment modality for small-cell lung cancer
(SCLC). However, in the limited stage, a combination of chemotherapy and thoracic
irradiation (TI) was found to be superior to chemotherapy alone by meta-analysis.
Recently, concurrent administration of cisplatin and etoposide with TI may be an
optimal treatment. The usefulness of prophylactic cranial irradiation in complete
responders was also confirmed by meta-analysis. Dose-intensive weekly
chemotherapy failed to improve the treatment outcome in the extensive stage.
Randomized trials to verify the effectiveness of high-dose chemotherapy with
peripheral blood stem cell transplantation are in progress.
PMID- 9757191
TI - [Recent issues in the treatment of advanced non-small-cell lung cancer].
AB - Unfortunately, most patients with non-small cell lung cancer (NSCLC) present with
clinically unresectable advanced neoplasms. Since local treatment like surgery
and radiation is not satisfactory for advanced NSCLC, effective systemic
chemotherapy is necessary. But NSCLC is relatively resistant to chemotherapy.
This report discusses the some recent issues in the treatment for advanced NSCLC.
the issues are the following: 1) effect of post-operative chemotherapy and pre
operative induction chemotherapy in the patients with stage IIIA N2 disease; 2)
efficacy combining chemotherapy with thoracic radiotherapy (TRT) in unresectable,
locally advanced NSCLC; 3) timely combination of TRT and chemotherapy; 4) effect
of chemotherapeutic agents as radiosensitizer; 5) potential effect of combination
of TRT and new agents in unresectable, locally advanced NSCLC; 6) contribution of
surgery following induction chemo-radiotherapy in locally advanced NSCLC; 7)
reasons why response rate in cancer chemotherapy for advanced NSCLC does not
always correlate with survival; 8) survival benefit of cancer chemotherapy in
metastatic NSCLC; and 9) promising new agents (irinotecan, paclitaxel, docetaxel,
vinorelbine and gemcitabine) along with combination chemotherapy, including these
new agents.
PMID- 9757192
TI - [Update of ovarian carcinoma].
AB - Correct histopathologic diagnosis of ovarian carcinoma is essential, because
biological behavior of the disease varies by the histologic subtype and its grade
of differentiation. The standard treatment modality of advanced ovarian carcinoma
has consisted of an initial maximal surgical effort and subsequent platinum-based
chemotherapy, followed by a secondary surgery. "Maximal surgical effort" is a
convenient term but it does not define a surgical procedure. In USA, since 1996,
paclitaxel/cisplatin had become a 1st-line regimen. Introduction of other potent
agents including topotecan/CPT-11 and previous evidence of the efficacy of
doxorubicin have made it difficult to decide which regimen is the most potent. A
maximal effort should be made at the second surgical attempt after completing a
planned 1st regimen. Finally, we should obtain a pathologically complete response
with the combined use of surgery and chemotherapy to achieve long-term survival
in patients with advanced ovarian carcinoma.
PMID- 9757193
TI - [Treatment of advanced cervical cancer].
AB - Patients with advanced-stage cervical cancer are treated with radiation. Although
5-year survival rates of about 40 percent are reported, there is clearly room for
improvement. The potential usefulness of neoadjuvant chemotherapy (NAC) before
planned surgery is under investigation. The clinical response to NAC seems to be
related to survival. Neoadjuvant chemotherapy before planned radiation therapy
has not been demonstrated to provide a benefit. In the area of concomitant
chemotherapy and radiation, a number of clinical trials have been completed or
are under way, but at this time there is no proven benefit to combining
chemotherapy with radiation. It is very interesting that concomitant weekly
cisplatin and prophylactic paraaortic radiation was reported to improve survival.
PMID- 9757194
TI - [Recent controversy in treatment for advanced bladder cancer].
AB - We summarized here the current status and controversy surrounding treatment for
advanced bladder cancer, which may be defined as deeply invasive bladder cancer
or invasive bladder cancer with distant metastasis. The definitive treatment for
advanced bladder cancer is considered to be systemic chemotherapy. However,
favorable results are not always obtained from CDDP-based combination
chemotherapy alone. Therefore, the development of a dose-intensified regimen
using G-CSF, intra-arterial chemotherapy, based on the concept of the drug
delivery system, and combination therapy of radiation and chemotherapy, produced
better results. Surgical treatment, a part of a multidisciplinary approach, may
result in a complete response followed by a good prognosis.
PMID- 9757195
TI - [Chemotherapy for pulmonary metastases of soft tissue sarcoma].
AB - The role and value of chemotherapy for soft tissue sarcomas remain unclear.
Seventeen patients with pulmonary metastatic soft tissue sarcomas underwent
treatment with chemotherapy, and the clinical efficacy and prognosis were
studied. Six patients with synovial sarcomas, 4 with malignant fibrous
histiocytomas, 4 with neurosarcomas, and the remaining 3 patients with
leiomyosarcoma, extraskeletal osteosarcoma, and extraskeletal chondrosarcoma,
were studied. Cases with small round cell sarcomas were excluded. The
chemotherapy agents were ifosfamide in 10 cases, combination of ifosfamide and
adriamycin in 5 cases, or cisplatin and adriamycin in 2 cases. Of the 17
patients, seven had partial responses radiographically and five had pulmonary
metastases from synovial sarcoma. Eight patients underwent resection of pulmonary
metastases following chemotherapy, and they were found to be residual tumor cells
histologically. Twelve of the patients died of disease at 6-108 months (median,
30 months) from the time of the initial therapy, and five patients have survived
from 1-53 months (median, 30 months). The absolute three-year survival rate,
according to the Kaplan-Meier method, for all 17 patients was 39%. In the two
cases with no change and progressive disease, all patients were dead within 2
years, while in the seven partial response cases, two patients were dead, four
were alive with pulmonary metastases, and only one case was disease-free at this
writing. The survival rate for patients with partial response was significantly
higher than for patients with no response. Although the cure rate of pulmonary
metastatic soft tissue sarcomas is still low, the combination of chemotherapy and
surgery has been shown to result in prolonged survival.
PMID- 9757196
TI - [Effect on hepatic function of hepatic artery infusion chemotherapy using
epirubicin and mitoxantrone for advanced hepatocellular carcinoma].
AB - This study was designed to assess the effect of hepatic dysfunction from hepatic
artery infusion (HAI) in advanced hepatocellular carcinoma (HCC). The patients
were randomly assigned to receive epirubicin (n = 12, Epi group) or mitoxantrone
(n = 14, Mito group) once every 4 weeks between 1992 and 1996. HCC patients were
given 6-8 mg of mitoxantrone or 30-40 mg epirubicin. There was hepatic
dysfunction in 27 patients after HAI, showing similarly elevated GOT, GPT, and
total bilirubin. In the Epi group, the GOT value was slightly higher than in the
Mito group, but it was not significant. After HAI chemotherapy, the GOT value
showed a more than two-fold elevation. Six patients in the Epi group and 2 in the
Mito group showed a significant difference. Our results indicated that
mitoxantrone had less impact on hepatic function following HAI therapy.
PMID- 9757197
TI - [Results of clinical study with epirubicin hydrochloride injectable solution in
hepatoma].
AB - A 10-center cooperative clinical study with a new formulation of epirubicin
hydrochloride injectable solution (Epirubicin-RTU) was conducted in patients with
hepatocellular carcinoma. Epirubicin-RTU 60 mg/m2 was injected into the hepatic
artery and a three-week drug-free interval followed. Of 15 patients with
hepatocellular carcinoma registered in this study, 14 patients were eligible, and
they all completed the entire course. The objective was to investigate the safety
of treatment with Epirubicin-RTU in 14 eligible patients. The adverse drug
reactions frequently observed in these 14 eligible cases were leukopenia,
neutropenia, thrombocytopenia, alopecia, and fever. They were all reversible and
tolerable. With these results. Epirubicin-RTU was considered to be a safe
pharmaceutical product to inject into the hepatic artery.
PMID- 9757198
TI - [Results of clinical study with epirubicin hydrochloride injectable solution and
cyclophosphamide in breast cancer].
AB - A 10-center cooperative clinical study with a new formulation of epirubicin
hydrochloride injectable solution (Epirubicin-RTU) was conducted in patients with
breast cancer. One course of treatment consisted of one intravenous
administration of Epirubicin-RTU at the dose of 60 mg/m2 followed by a 3-week
drug-free interval and concomitant daily administration of oral cyclophosphamide
at 100 mg/day during the period between Days 1 through 14. At least, two courses
of treatment were given. Among 20 registered cases, all 20 cases were eligible
and 16 cases completed the whole course of the study. In 16 completers, PR was
observed in 5 cases, indicating the efficacy rate of 31.3% (5/16).. No local
irritation was observed at the injection sites. Adverse reactions frequently
observed were leukopenia, neutropenia, anorexia, alopecia, and nausea/vomiting,
which were all reversible and tolerable. From the above results, Adverse
reactions both locally and systemically were tolerable. Intravenous
administration of Epirubicin-RTU was considered to be useful for the treatment of
breast cancer.
PMID- 9757199
TI - [Mobilization of peripheral blood stem cells in advanced ovarian cancer].
AB - High-dose chemotherapy with hematopoietic support has been expected to improve
the survival of advanced ovarian cancer patients in recent years. An essential
component of such treatment has been the ability to collect and reinfuse a large
number of peripheral blood stem cells (PBSCs) following high dose therapy. This
study was designed to determine which clinical and hematological factors would be
better indicators to collect the proper volume of PBSCs. Thirteen patients
received a total of 24 courses of induction chemotherapy and 69 of apheresis. We
usually mobilized stem cells using CEP chemotherapy (cisplatin 50-70 mg/m2,
epirubicin 50 mg/m2 and cyclophosphamide 1.5 g/m2) with G-CSF and CEE regimen
(cyclophosphamide 2.0 g/m2, epirubicin 50 mg/m2, and etoposide 50 mg/m2) as a
salvage for mobilization. We obtained an average 5 x 10(6)/kg of CD34+ cells for
3 days as one course. The number of CD34+ cells collected significantly depended
on the platelets and reticulocytes on the first day of apheresis, but not a nadir
of WBCs. It is concluded that apheresis should be started on recovery of WBCs to
5,000-10,000/microliters, of immature granulocytes to > or = 10% and of
reticulocytes to > or = 20%. This study confirmed the feasibility of collecting
enough PBSCs to use standard chemotherapy of ovarian cancer patients.
PMID- 9757200
TI - [High-dose chemotherapy with autologous peripheral blood stem cell transfusion in
the treatment of advanced testis cancer].
AB - Four patients with advanced testis cancer were treated by high-dose chemotherapy
supporting by autologous peripheral blood stem cell transplantation. High-dose
chemotherapy (carboplatin 250 mg/m2 or nedaplatin 200 mg/m2, etoposide 1,500
mg/m2, ifosphamide 7.5 g/m2 was given and peripheral blood stem cell transfusion
was performed 72 hours after the last dose of chemotherapy. High-dose
chemotherapy. was given followed by 1 or 2 cycles of pre high-dose therapy
consisting of cisplatin 100 mg/m2 or carboplatin 500 mg/m2, etoposide 450 mg/m2,
ifosphamide 6 g/m2. All 4 patients were evaluable. Three patients obtained a
complete response and one showed a partial response. The partial responder was
given RPLND. The RPLND specimen showed necrotic tissue.
PMID- 9757201
TI - [Efficacy and safety of two methods of administration of granisetron injection
for nausea and vomiting induced by chemotherapy for tumors in hematopoietic
organs--a randomized crossover comparison between intravenous drip infusion and
intravenous bolus injection].
AB - We investigated the efficacy and safety of two methods of granisetron injection
to treat nausea and vomiting induced by chemotherapy for tumors in hematopoietic
organs. The methods of administration were intravenous drip infusion over 30
minutes, which is the conventional method, and intravenous bolus injection. In
this study, 89.5% of patients in both groups (17/19 for each) were free from
vomiting. No serious adverse events were observed in either administration group.
Abnormal laboratory test values suspected to be related to granisetron were
observed in 3 cases in the bolus injection group and in 2 cases in the drip
infusion group. but did not pose any clinical problem. These results demonstrated
the safety of both methods of administration. In conclusion, it is considered
that granisetron intravenous bolus injection can be considered as the method of
choice for the prevention of nausea and vomiting induced by chemotherapy for
tumors in hematopoietic organs.
PMID- 9757202
TI - [Effect of combination chemotherapy of low-dose CDDP. Continuous infusion of 5
FU, and intermittent CPT-11 administration for 2 advanced pancreatic cancer cases
with liver metastasis].
AB - For advanced pancreatic cancer, there is no typical chemotherapy regimen non
single chemotherapeutic agent. For example, 5-FU, Doxorubicin, MMC and Epirubicin
obtained only 15-24% efficacy, and general combination chemotherapy was FAM, 5
FU+CDDP and 5-FU+Leucovorin for pancreatic cancer. Generally, in pancreatic
cancer cases the performance status was poor, and most could not endure the
chemotherapy regimen. 5-FU continuous infusion and low-dose CDDP regimen were
effective and showed fewer side effects for pancreatic cancer. Then, for 2 cases
of advanced pancreatic cancer with liver metastasis, 5-FU continuous infusion +
low-dose CDDP + intermittent CPT-11 administration (5-FU 500 mg/body/24 hr + CDDP
5mg x 5 days-6 courses + CPT-11 100 mg-125 mg-150 mg, bolus i.v. intermittently)
was effective. Thus, this regimen could well be effective for advanced pancreatic
carcinoma.
PMID- 9757203
TI - [Three cases of colorectal cancer with lung metastasis successfully treated with
combination chemotherapy using 5'-DFUR and MMC].
AB - Three patients with colorectal cancer and pulmonary metastasis who had previously
undergone surgical treatment, were treated by combination chemotherapy with CDDP
and 5-FU regimen, but the growth of the metastatic tumor could not be controlled
finally. Thus, a new strategy of combination chemotherapy using 5'-DFUR and MMC
were investigated in these cases, and resulted in suppressing the tumor growth
successfully without admission. The procedure for treating pulmonary metastasis
of colorectal cancer has not been established clearly. This new regimen may play
an important role from the standpoint of not only its effectiveness against tumor
growth but also the quality of life of patients.
PMID- 9757204
TI - [Complete remission of liver metastasis from rectal cancer following continuous
oral administration of tegafur-uracil after intrahepatic arterial single
injection of CDDP and 5-FU].
AB - An intrahepatic arterial injection of CDDP, 5-FU, followed by ten months of oral
tegafur-uracil administration (2g/day), induced remission for 3 months or more in
a 72-year-old male with rectal cancer and synchronous liver metastasis subsequent
to anterior resection of the rectum. Tegafur-uracil showed an excellent
anticancer effect against colorectal metastatic liver cancers without loss of QOL
because a single-low dose of intraarterial anticancer injection was followed by
continuous oral administration of tegafur-uracil, and the chemotherapy could be
managed to obtain complete remission of the hepatic lesion.
PMID- 9757205
TI - [Appropriate intravesical retention time of pirarubicin concentration based on
its level in tumor tissue, anti-tumor effect and side effect in intravesical
instillation therapy for bladder tumor].
AB - The present study was designed to investigate the appropriate intravesical
retention time of pirarubicin (THP) for the treatment of bladder tumor in terms
of its anti-tumor effect and side effect. We administered THP to 22 patients with
superficial bladder tumor intravesically and measured the THP concentration in
the tumor tissues. Patients were divided into 3 groups by retention time; 8 for
30 minutes, 8 for 1 hour and 7 for 2 hours. Tumor tissues were obtained by
transurethral resection 30 min., 1 or 2 hours after the intravesical instillation
of THP at the fixed concentrations of 30 mg/30 ml. There was no significant
difference in THP concentration between 3 groups. This indicates that the anti
tumor effect of intravesical instillation of the THP would be expected by only 30
min. of intravesical retention time at the THP concentration of 30 mg/30 ml.
Then, we administered 30 mg/30 ml of THP solution for 30 min. to 10 patients
intravesically 6 times every 48 hours to investigate its clinical anti-tumor
effect and side effect. There were 2 complete responses, 3 partial responses and
5 cases with no changes for a total response rate of 50%. No side effect was
observed. It is considered that 30 min. of intravesical retention time at the THP
concentration of 30 mg/30 ml would be appropriate in terms of its anti-tumor
effect and side effect.
PMID- 9757206
TI - [Increased effect of neocarzinostatin bound to chimeric Fab fragments of
monoclonal antibody A7 on the proliferation of human pancreatic carcinoma].
PMID- 9757208
TI - [Comparative study of 5'-DFUR administration of single time per day versus two or
three times].
PMID- 9757207
TI - [The correlation between thymidine phosphorylase activity of renal cancer cells
and the chemosensitivity to 5-FU and 5'-DFUR].
PMID- 9757209
TI - [Comparative study of 5'-DFUR administration in patients with elderly cancer].
PMID- 9757210
TI - [TNM classification: cancer of the stomach].
AB - The 5th edition of TNM Classification was published by the UICC (International
Union Against Cancer) in 1997. In the classification of gastric cancer,
anatomical subsites and N category were newly published. The new classification
and role of the Japanese TNM Joint Committee were described in this paper. The
Japanese committee had strongly advocated to continue "the anatomical N
classification", because the hazard ratios were more significant for prognosis of
patients with gastric cancer, and had many reasonable and scientific advantages.
However, the UICC introduced "a new N classification by number of metastatic
lymph nodes" because of the difficulty in studying nodes by anatomical
classification. The new TNM can not be considered an improved classification, and
so we are looking for a more scientific, practical, and internationally
acceptable classification.
PMID- 9757213
TI - [MRI and traumatic osteoarticular pathology: for a rational application].
PMID- 9757214
TI - [Percutaneous transhepatic biliary drainage].
PMID- 9757215
TI - [Diagnostic imaging of acute pulmonary embolism: critical analysis of the 1997
literature].
AB - With variable symptoms and a nonspecific radiographic appearance, acute pulmonary
embolism (APE) is a frequent and often undiagnosed cause of mortality and
morbidity; thus, availability of an accurate, noninvasive screening examination
is highly desirable. Until recently, various noninvasive imaging procedures have
been used to detect APE, including ventilation-perfusion scanning, MR imaging and
phlebography (or sonography). The low specificity of scintigraphy explains why
pulmonary angiography remains the usual "gold standard" modality for detection of
APE. However, with this procedure morbidity and mortality not zero-Helical
computed tomography (HCT) seems to be an accurate technique for diagnosis of
pulmonary embolism except for distal thrombi. Nevertheless the exact position of
HCT in the classic algorithms remains to be defined, particularly in terms or
cost-benefit results.
PMID- 9757216
TI - [Imaging cranial nerves with inframillimetric T2-weighted MRI].
AB - Fifty files were evaluated to determine the normal anatomy of the cranial nerves.
All the cranial nerves were studied including the labyrinth, in different planes
with a 3DFT-CISS imaging technique. The 3DFT-CISS is especially interesting to
study cranial nerves because of the excellent contrast with CSF-fluid and the
possibility of thin sections. It might be essential for the diagnosis of
neuralgia and cranial nerves paralysis.
PMID- 9757217
TI - [Comparative study of tumor evaluation with computerized tomography and surgery
in ovarian cancer].
AB - PURPOSE: To evaluate the results of an abdomino-pelvic scan in cancers of the
ovary in comparison with surgery. MATERIAL AND METHODS: We reviewed the
observations concerning patients operated on for malignant tumors of the ovary
between January 1992 and April 1995 in our anti-cancer center. We selected 32
patients who had had both a complete surgical abdominal exploration (laparotomy
or laparoscopy) and an abdominal pelvic scan in the preceding months. We divided
the abdomen into 33 areas and compared the scan of each with the surgical
findings. Two cancer radiologists, including one gynecology specialist, studied
the imaging separately. Neither knew the results of the surgical observations.
RESULTS: Imaging findings varied with localization tumor size and presence or not
of ascites radiologists. For certain localization, detection of lesions was
difficult for both readers (pancreas, spleen, stomach), for others, recognition
improved with experience (bowel, diaphragm, colon). CONCLUSION: The clinician
must be aware of the variability of ovarian cancer assessment by CT scan,
particularly if imaging alone is being used to guide treatment.
PMID- 9757218
TI - [Esophageal morphology with ultrasound imaging after laryngectomy: effect on
quality of esophageal speech].
AB - PURPOSE: In patients with aerodigestive cancer, laryngectomy places the esophagus
in a superficial position, allowing easy ultrasound examination of this organ.
The purpose of the present study was to assess oesophagus morphology after
laryngectomy using echotomography and to compare this morphology with voice
quality. MATERIAL AND METHODS: In the present study, ultrasonography was
performed in 28 patients (delay from surgery: 3 +/- 3 years): 15 were operated
using laryngectomy technique (LT) and 13 with pharyngolaryngectomy technique
(PLT). On transversal echography, antero-posterior and latero-lateral diameters,
esophagus area and dilatation during phonation were systematically measured.
These data were compared to the voice quality assessed by two independent
observers. RESULTS: A smaller latero-lateral diameter and area were found in the
PLT group than in the LT group (p < 0.05) with a flat aspect in group LT. This
was associated with faster and better voice acquisition in the PLT group.
CONCLUSION: Morphologic study of the esophagus after laryngectomy using
ultrasound is in favor of pharyngolaryngectomy technique which allows better
conditions for acquiring esophageal voice in better conditions. This could be due
to the small area, circle shape and tonicity of the esophagus after this type of
surgery.
PMID- 9757219
TI - [Percutaneous self-expanding metallic endoprosthesis and malignant biliary
stenoses].
AB - METHOD: Thirty-five patients with malignant obstructive jaundice were given
palliative treatment by percutaneous self-expandable metallic stents.
Cholangiocarcinoma was the most frequent cause of biliary obstruction. The
stricture was located in the hilum in more of 50% of cases. RESULTS: Adequate
biliary drainage was achieved in 97% of cases. Median survival was 182 days. 11%
of patients have died within 30 days. Early complications occurred in 31% of
patients. 25% of patients have shown recurrent jaundice after an average of 180
days. CONCLUSION: Percutaneous self-expandable metallic stents are an efficient
means treating malignant biliary strictures, particularly of upper biliary
obstructions.
PMID- 9757220
TI - [Magnetic resonance imaging of tibial periostitis].
AB - Tibial periostitis frequently occurs in athletes. We present our experience with
MRI in a series of 7 patients (11 legs) with this condition. The clinical
presentation and scintigraphic scanning suggested the diagnosis. MRI exploration
of 11 legs demonstrated a high band-like juxta-osseous signal enhancement of SE
and IR T2 weighted sequences in 6 cases, a signal enhancement after i.v. contrast
administration in 4. Tibial periostitis is a clinical diagnosis and MRI and
scintigraphic findings can be used to assure the differential diagnosis in
difficult cases with stress fracture. MRI can visualize juxta-osseous edematous
and inflammatory reactions and an increased signal would appear to be
characteristic when the band-like image is fixed to the periosteum.
PMID- 9757221
TI - [Ureteral hematoma complicating anticoagulant treatment].
AB - Submucosal hemorrhage of the ureters, are a very uncommon quoted cause of
hematuria when overdosing anticoagulants. We report two cases, CT shows some very
typical aspects but can also highlight, as reported formerly, another associated
complication: parietal hematoma of the small bowel.
PMID- 9757222
TI - [Rare cause of ischemic cerebrovascular infarct in a young patient: cardiac
hydatic cyst].
AB - The authors report the case of a 28-year-old man in whom the diagnosis of hydatic
cyst of the heart was strongly suspected on echocardiography and CT-scan and
confirmed by surgery. The interest of this case is based the total clinical
latency of this hydatic cyst discovered by echocardiography during a systematic
checkup for cerebrovascular disorders. Echocardiography and spiral scanography
with bidimensionnal reconstruction in coronal and sagittal planes allowed a rapid
anatomic and topographic diagnosis. CT-scan also identified spread of
echinococcosis and discovered a calcifield hydatid cyst of the liver and a
multivesicular hydatid cyst of the left kidney.
PMID- 9757223
TI - [Intrathoracic dislocation fracture of the head of the humerus].
AB - We present a rare case of fracture-dislocation of shoulder with intrathoracic
displacement of the humeral head. This case is well documented by CT. The
mechanism and treatment modalities are discussed, and pertinent literature is
reviewed.
PMID- 9757224
TI - [Left aortic arch with right descending aorta and right ligamentum arteriosum in
an infant].
AB - A rare form of vascular ring, consisting of a left aortic arch, a right
descending aorta and a right ligamentum arteriosum is reported in a symptomatic
infant. The role of MRI in the surgical planning is emphasized.
PMID- 9757225
TI - [What diagnosis? Appendicular abscess].
PMID- 9757226
TI - [MRI cholangiopancreatography and future exploration of ductal structures:
tournedos or carpaccio?].
PMID- 9757227
TI - [Organizations and networks. The English, the Americans...and us?].
PMID- 9757228
TI - [What is bright on T1 MRI scans?].
AB - The list of entities associated with a high signal intensity on T1-weighted
images is extensive and classically includes fat, proteins, hemorrhage, melanin
and gadolinium. However, additional entities may be responsible for abnormally
high signal intensity on T1-weighted images. These include ion deposition in
metabolic disorders, free radicals, increased proton density, flow phenomena,
some artifacts, and new contrast agents. The aim of this article is to display
both the common and uncommon causes for a high T1 signal intensity and to discuss
the underlying mechanisms or attributable pathophysiology for this phenomenon.
PMID- 9757229
TI - [Puerperal thrombophlebitis and the ovarian vein with extension to the inferior
vena cava].
AB - PURPOSE: To assess US, CT and MR findings in women having puerperal ovarian vein
thrombosis with clot protrusion into the inferior vena cava. PATIENTS, MATERIAL
AND METHODS: We retrospectively reviewed the duplex US (n = 9), CT (n = 5) and MR
(n = 5) examinations of 9 patients with 8 right ovarian vein thrombosis, and one
left ovarian vein thrombosis. RESULTS: US findings allowed for the diagnosis of
ovarian vein thrombosis in all patients in showing enlarged tubular echogenic
thrombus within the retroperitoneum with clot protrusion in the IVC in all cases.
CT scan and MRI demonstrated ovarian vein thrombosis in all the cases in which it
was performed but failed to show a mobile thrombus within the IVC in one patient.
CONCLUSION: Duplex US is a reliable technique to show puerperal ovarian vein
thrombosis and its extension to the IVC. CT scan and MR imaging can be used to
precise the extension to the IVC.
PMID- 9757230
TI - [Retrograde cystography after a first episode of acute pyelonephritis in the
child and adolescent].
AB - In spite of its invasiveness, voiding cystourethrography remains the gold
standard examination for detecting vesico-ureteric reflux. The aim of this study
was to determine if voiding cysto-urethrography is useful at any pediatric age in
girls after a first acute pyelonephritis. 152 patients have been retrospectively
studied. Both reflux frequency and grade progressively decreased according to
age. Sonography was unable to predict reflux. In more than 3-year-old girls, 8/30
children with reflux had voiding dysfunction. We suggest clinical and/or a flow
metric evaluation for voiding dysfunction prior to voiding cystourethrography.
After 9 years, reflux was so rare that voiding cystourethrography should be
discussed on an individual basis.
PMID- 9757231
TI - [CT-guided percutaneous treatment of inoperable pulmonary aspergilloma. Apropos
of 42 cases].
AB - The authors report 42 cases of symptomatic pulmonary aspergilloma treated by
intracavitary percutaneous injections of Amphotericine paste. These patients were
not considered as operable. The aspergillomas complicated tuberculosis sequels
and pulmonary fibrosis. Surgery was contraindicated in these patients on account
of severe respiratory failure. The authors specify the technique for the
preparation of the paste and for the type of percutaneous injection under CT
guidance; the aim being to obtain complete filling of the cavity and creating an
"anaerobic" environment for the aspergillus. The contribution of this technique
for the non-surgical treatment of patients appears interesting but should be
carried on a larger series to identify the exact indications and the interaction
with other treatments (drugs and surgery).
PMID- 9757232
TI - [MRI cholangiography with rapid spin-echo technique: prospective evaluation of 20
patients].
AB - PURPOSE: To evaluate a MR cholangiographic technique using a non breath-hold fast
spin-echo technique in patients with suspected bile duct obstruction. MATERIAL
AND METHODS: Twenty patients with suspected bile duct obstruction were
prospectively investigated with MR cholangiography using a T2-weighted non breath
hold fast spin-echo technique (TR = 8000-9000 mse, effective TE = 120-266 msec,
ETL = 16-32, acquisition time = 1-3 min) with a body coil. Results of MR
cholangiography were compared to those obtained with endoscopic retrograde
cholangiography (n = 20 patients) and endoscopic sonography (n = 12 patients)
that were considered as reference. RESULTS: MR cholangiography provided high
quality images in 19 out of 20 cases (95%). MR cholangiography had 100%
sensitivity, 100% specificity and 100% accuracy in the diagnosis of bile duct
dilation. MR cholangiography had 73% sensitivity, 75% specificity and 73%
accuracy in the diagnosis of bile duct obstruction. MR cholangiography failed to
depict small stones (< 3 mm) of the main bile duct in 4 cases in which no bile
duct dilatation was found. CONCLUSION: MR cholangiography using a non breath-hold
fast spin-echo technique depicts bile duct dilatation with a degree of accuracy
comparable to that achieved with endoscopic examination. In the absence of bile
duct dilatation, small stones of the main bile duct may be undetected with MR
cholangiography.
PMID- 9757233
TI - [Cavernous dural fistulas: Importance of trans-ocular Doppler ultrasound in
evaluating venous patency and therapeutic choices].
AB - Transcranial Duplex scan is a relatively recent diagnostic tool with many
unexplored clinical potentials. The authors insist on the role of transocular
exploration, as a non-invasive substitute to angiography and discuss two patients
with cavernous meningeal arteriovenous fistula, a benign but relatively uncommon
disease. In the first patient, in whom symptoms recurred, Duplex scan was able to
rule out thrombophlebitis and to show increased flow in the fistula, thus leading
to proper treatment. In the second patient, the identification of a periorbital
thrombophlebitis innocented the fistula and prompted anti-coagulation. We
conclude that besides its diagnostic capabilities, Duplex scan may be helpful in
selecting proper treatment and follow-up in specific neurovascular conditions.
PMID- 9757234
TI - [Focal intrahepatic siderosis, diagnostic pitfall, iatrogenic image].
PMID- 9757235
TI - [Adventicial cyst of the popliteal artery].
AB - In a 42-year-old man with intermittent calf claudication, cystic adventitial
disease of the popliteal artery was demonstrated by 3D CT. Cystic mass was seen
to be compressing the arterial lumen. The diagnosis of cystic adventitial was
confirmed by surgery. Compared with color doppler sonography, MR Imaging, 3D CT
provides additional useful anatomic information concerning disease of the
popliteal artery, usually gained only with sonography or arteriography.
PMID- 9757236
TI - [Late perforation of pre-sternal coloplasty: echocardiography diagnosis].
AB - The authors report a previously non described case of late rupture of a
presternal colon esophagoplasty in a patient with history of caustic ingestion.
The role of sonography was the diagnosis of the rupture due to presternal
position of the coloplasty.
PMID- 9757237
TI - [What diagnosis? Ureteral pseudodiverticulosis].
PMID- 9757238
TI - [Interuniversity diploma in cardiovascular imaging: a luxury or a necessity?].
PMID- 9757239
TI - [Fistulas in chronic hemodialysis].
PMID- 9757240
TI - [Scientific committee of the French radiology workshops: "how to use"].
PMID- 9757241
TI - [Role of transcranial ultrasonography in neuroradiological diagnosis].
AB - Blood flow within the major arteries supplying the brain can be studied with
transcranial Doppler sonography, a noninvasive, portable procedure. We describe
the technique of examination, as well as indications in children and adults such
as the investigation of intracranial stenosis, collateral pathways, vasospasm,
cerebral emboli and arteriovenous malformations.
PMID- 9757242
TI - [Radiological expertise and diagnosis. I. Theoretical advances].
AB - From the cognitive point of view, experts are characterized (1) by the ability to
directly perceive large meaningful structures due to the development of numerous
links within their knowledge networks, particularly between categories that, in
manuals, are described as mutually exclusive (2) by the automation of diagnosis.
Even in the best experts, some biases remain, mainly due to filters in facts and
hypotheses selection. These filters are based upon the resemblance of the case
with prior knowledge, and upon the likelihood of previous encountering similar
cases. Biases are partially balanced by heuristics which are reasoning processes,
valid for a majority of cases, but which induce some errors on atypical cases.
PMID- 9757243
TI - [Radiological expertise and diagnosis. II. Empirical study].
AB - In order to study cognitive processes of radiological diagnosis, 22 radiologists
with different experience levels interpreted two complex films, with no clinical
data. Exploration strategies, used knowledge and reasoning were analyzed.
Experimented radiologists interpreted clues more easily, using richer and more
integrated knowledge. They used a symptomatic exploration, guided by hypotheses
that related to salient cues. Cues that were both subtle and unexpected were
better detected by novices and "super experts" than by intermediates and "basic
experts". Novices detected those cues by mean of a systematic exploration. "Super
experts" benefitted from an increased likelihood of unexpected cue detection due
to longer and more supported reasoning. Also, they might have complemented the
symptomatic exploration with an automatic systematic one.
PMID- 9757244
TI - [MRI diagnosis of sinus cavernous invasion by pituitary adenomas].
AB - PURPOSE: To evaluate the preoperative MRI criteria of a sinus cavernous invasion
by a pituitary adenoma. MATERIAL AND METHODS: Study of 102 cavernous sinuses
among 51 patients who had had a surgical cure of pituitary adenoma. Thirteen
patients had a surgical invasion of the cavernous sinus. RESULTS: A certain
number of signs eliminated cavernous sinus invasion. The best means consisted in
not crossing the intercarotid line (Sensitivity-Se = 100%, Specificity-Sp = 85%
and Negative Predictive Value-NPV = 100%). The others means implied: not going
past twelve o'clock on the internal carotid artery-ICA (NPV = 97.1%), symmetrical
size of the cavernous sinus (NPV = 92.5%), non-convexity of the lateral wall (NPV
= 90.2%), visualization of at least two venous groups of the laterosellar space
(NPV = 90.2%) and finally, non-displacement of the ICA (NPV = 89.2%). The best
criteria for diagnosis were passing by the intra and supracavernous ICA lateral
tangent (Se = 84.6%, Sp = 95%) and the percentage of ICA encasement by the
adenoma exceeding 25% (Se = 92.3%, Sp = 85%). CONCLUSION: Except the total
encasement of the intracavernous ICA, the cavernous sinus can be invaded when the
lateral tangent of the supra and the intracavernous ICA is crossed, and also when
the percentage of ICA encasement exceeds 25%.
PMID- 9757245
TI - [Rare cases of bladder tumors].
AB - Among epithelial tumors, squamous cell carcinomas represent only 3 to 7% of the
cases in the temperate countries, but constitute the most frequent histologic
kind in bilharzien endemic zones and 17% of intradiverticulars tumors. The
adenocarcinoma is found most often in the bladder dome, representing only 0.3 to
3% of all bladder tumors. Invasive cancer in a neighboring organ (digestive
tract, genital organs) must be eliminated. In most cases, combining
ultrasonography and intravenous urography can be helpful for diagnosis of
intradiverticular carcinoma or bladder dome tumor. Computed tomography and
magnetic resonance images are the best methods for positive diagnosis and
extension exploration for tumors of the dome and base of the bladder. In this
work, we report a series of five cases of uncommon bladder carcinoma. Three of
the cases were intradiverticular squamous cell tumors and two were adenocarcinoma
of the bladder dome.
PMID- 9757246
TI - [Percutaneous recanalization of proximal venous thromboses in chronic
hemodialysis patients].
AB - Occlusion of the proximal vein in chronic hemodialysis patients results in vein
hypertension and a "swollen arm". The usual treatment for this "swollen arm"
consists in closing up the fistula and making another access on the contralateral
member. But this is not always possible and, with some patients, recanalization
is the only solution. We have performed 4 recanalizations successfully: 2
accesses remain permeable after 10 and 24 months, another patient needed to be
fitted with two endoprosthesis just after recanalization and access, in his case,
remained permeable until he died of intestinal ischemic syndrome six months
later. The fourth patient presented a reocclusion two months later but could not
be reoperated on because of bad general state of health. An attempt to perform
recanalization on a fifth patient was a failure. Such results show that
recanalization of a thrombosed proximal vein is worth attempting before closing
access for good.
PMID- 9757247
TI - [Synovial sarcoma localized in the muscles].
AB - We report three cases of synovial sarcoma strictly located in the muscles.
Synovial sarcoma generally arises in the vicinity of joints, tendon sheaths,
bursae, fascia, and ligaments. Strictly intramuscular locations are not well
known and not described in the literature to our knowledge although they seem to
be frequent. The different characteristics on the radiographic examinations are
non specific, and this location may be misleading. MRI is considered the
procedure of choice for staging this tumor and to visualize soft tissues and bone
invasion. CT scans may be useful in detecting more specific small calcifications.
PMID- 9757248
TI - [Bladder herniation in a inguinal-scrotal hernia complicated by acute renal
insufficiency].
AB - We report one case of massive inguino-scrotal bladder herniation which was
responsible for an acute obstructive renal insufficiency. The different types of
bladder hernias and their anatomic factors are described. The clinical
radiological findings and surgical management are discussed.
PMID- 9757249
TI - [Abnormality of hepatic perfusion in superior vena caval obstruction syndrome. A
case report diagnosed by CT scan].
AB - We describe a case of focal and intense contrast enhancement on hepatic CT due to
superior vena caval obstruction and brachiocephalic vein obstruction. This
phenomenon is explained by systemic portal venous shunting.
PMID- 9757250
TI - [Post-traumatic intrasplenic arteriovenous fistula in a child. Spontaneous
regression].
AB - We report on an 11-year-old boy who developed splenic arteriovenous fistula
resulting from blunt abdominal trauma. This fistula disappeared spontaneously
after 8 months of follow-up without any complication.
PMID- 9757251
TI - [Magnetic resonance imaging of multiple myeloma].
PMID- 9757252
TI - [Diagnostic and prognostic value of magnetic resonance imaging in multiple
myeloma: the clinician's point of view].
PMID- 9757253
TI - [Value of high-frequency ultrasonography (20MHz) in the diagnosis of cutaneous
tumors].
PMID- 9757254
TI - [Can we optimize radioprotection for medical workers?].
AB - Implementation of the principle of optimization (ALARA), an essential radiation
protection regulations, remains very limited in the medical field, even though
80% of workers whose exposure exceeds 50 mSv are to be found in this domain. The
doses measured by legal dosimetry sometimes underestimate the real exposure of
workers. It is therefore necessary to optimize the protection of occupational
exposure in the medical field. This paper reviews the steps of the optimization
procedure with emphasis on specificity of its application in this domain.
Operational dosimetry as well as information on the residual risk due to low
exposures and a better estimation on the risk/benefit factor for the patient are
needed for satisfactory implementation.
PMID- 9757255
TI - [Value of high-frequency (20 MHz)in the diagnosis of cutaneous tumors].
AB - The purpose of the present study is to asses the value of high frequency
ultrasonography (20 MHz), a new noninvasive imaging technique, in cutaneous
tumors. Cutaneous tumors are clinically varied and their diagnosis is still based
on histopathological analysis. 140 cutaneous tumors have been examined with US
and imaging findings have been compared to the results of clinical and
histological examinations. This study shows that high frequency ultrasonography,
even though it cannot replace pathological analysis, may help the dermatologist
in the positive diagnosis of some cutaneous tumors and in accessing the location
and the in depth-extension of the lesions in the different layers of the skin.
PMID- 9757256
TI - [Digital image processing of screening mammographies: application to masses].
AB - A method based on image processing of tumoral neighbourhood is described for
studying masses. By using polar and pseudopolar representations for the tumor and
its neighbourhood, it is possible to detect divergent structures around the
lesion and to evidence fuzzy areas in the boundary of the tumor, which constitute
two significant features of breast cancer. The degree of spiculation is deduced
from a shape parameter that characterizes the irregularity of the boundary; the
radial component of the gradient on the boundary provides a measurement of fuzzy
appearance.
PMID- 9757257
TI - [Renal insufficiency with AIDS: ultrasonographic aspects].
AB - Renal pathologic changes in AIDS involve various factors and can also occur in
several other forms of renal disease. Renal sonography was prospectively
performed in 31 patients with laboratory evidence of AIDS and renal
insufficiency. All patients included in this study were without clinical
manifestations (group II of the CDC) and without risk factors of AIDS. AIM: to
characterize renal pathologic changes underlying the sonographic findings in
these patients. Sonographic evaluation included determination of renal sizes and
renal echogenicity according to standard grading system. Sonography showed normal
sized or enlarge-sized kidneys. Enlarged kidneys were generally due to increased
thickness rather than length or width; small-sized kidneys were not observed.
Grading echogenicity showed: grade 0 in 3 patients, grade I in none, grade II in
11 patients and grade III in 17 patients. In six patients, we found "spotted"
echostructural figure due to several hypoechoic and rounded zones. Echogenicity
increased with the severity of renal insufficiency. Our study suggests that renal
abnormalities are varied and can occur in all stages in the course of the
disease. The particular "spotted" figure associated with enlarged size at the
expense of thickness of kidneys must draw radiologist's attention to the
probability of AIDS lesions. Further studies with large populations must be
performed to confirm our observations.
PMID- 9757258
TI - [CT x-ray evaluation of abdominal and pelvic veins in patients suspected of acute
pulmonary embolism with negative Doppler sonography].
AB - PURPOSE: To address prospectively the potential of CT of the abdomen and pelvis
to demonstrate deep vein thrombosis in patients suspected of acute pulmonary
embolism and investigated with helical CT of the pulmonary arteries. MATERIAL AND
METHODS: 197 patients presenting non-diagnostic scintigraphy and negative Doppler
US of lower limbs and IVC were included. They had helical CT of the pulmonary
arteries (5mm collimation, 1:1 pitch, reconstruction every 2.5 mm, injection of
120 mL of contrast media at a rate of 3 mL/sec). Ninety seconds after the end of
the thoracic acquisition, abdominal and pelvic CT were acquired (7 mm collimation
every 12 mm). RESULTS: 3 (1.5%) of 197 patients had an unknown thrombosis of the
caval system (renal vein, ovarian vein, lilac veins). A fourth patient had an
unknown thrombosis of the mesenteric vein. All these patients had a pulmonary
embolism (4/40). None of the 157 patients without pulmonary embolism at helical
CT showed deep venous thrombosis. CONCLUSION: In our study, CT of the abdomen and
pelvis disclosed an unknown thrombosis of a deep vein of the abdomen and pelvis
that can explain the pulmonary embolism in 7.5% of patients.
PMID- 9757259
TI - [Image quality and optical density in mammography: study on phantoms].
AB - Optical densisty (od) is an important factor for image quality in mammography. We
studied the effect of o.d. on the image score with two phantoms (Contrast Detail
MAMmography phantom (CDMAM), University Hospital Nijmegen, The Netherlands and
breast-equivalent phantom (MTM 100) made by CIRS in the United States). We also
evaluated the doses required to obtain the blackening considered from
measurements made with thermoluminescent pastilles. Two series of exposure were
performed at 28 kV with mAs ranging from 25 to 100 to obtain a range of o.d.
varying between 0.72 and 2.67. Image scores were then evaluated for each negative
by calculating the mean of five different readers. The study showed a clear
increase of the image score with o.d. These observations were consistent with
other studies. For the two phantoms and the screen-film combination used, the
maximum quality was obtained for an o.d. of 1.6, but the drawback of negatives at
high o.d. is increase of the irradiation dose from 5,4 to 7,2 mGy when the o.d.
increases from 1.30 to 1.70.
PMID- 9757260
TI - [Inflammatory spondylodiscitis as a unique radiological manifestation of the
SAPHO syndrome].
AB - We describe two cases of SAPHO with an exclusive spinal involvement. Diagnosis
was established by sterno-clavicular arthralgias, palmar and plantar pustulosis
and by radiological signs of inflammatory spondylodiscitis and vertebral
osteitis. Spondylodiscitis and medullary edema resolved as shown by MRI after
administration of steroids in one case and methotrexate in the other.
PMID- 9757262
TI - [Spontaneous hyperintensity of the anterior pituitary gland in MRI T1-weighted
images related to manganese deposits in a patient undergoing prolonged parenteral
nutrition].
AB - The signal abnormalities found on MRI in the basal ganglia in patients with an
increased plasmatic level of manganese are well known. We report a case with a
hyperintense signal in a patient with a high plasmatic level of manganese due to
long term parenteral nutrition. The normal signal intensity of T2-weighted
imaging in the anterior pituitary gland helps to differentiate the increased
signal intensity of T1 weighted imaging due to deposition of manganese from
hemorrhagic or fatty lesions.
PMID- 9757261
TI - [Regression of a focal nodular hyperplasia after stopping oral contraceptives].
AB - The complete regression of a focal nodular hyperplasia of the liver with typical
MRI patterns 5 years after withdrawal of oral contraceptives was observed.
Effects of oral contraceptives on this tumor's evolution and appropriate imaging
by MRI are discussed.
PMID- 9757263
TI - [A rare mediastinal-hilar pseudotumor: esophageal and azygos vein varices].
AB - Mediastinal pseudotumors are present in less than 5% of patients with long
standing portal hypertension. These pseudotumors may be caused by para-esophageal
collateral vessels or greatly dilated azygos or hemiazygos veins. Enhanced CT
seems to be the best tool for the diagnosis and in evaluating the overall status
of portosystemic collateral vessels. In this case report, MRI ruled out tissular
mass by showing vascular signal.
PMID- 9757264
TI - [What is it? Bilateral sacroilitis and avascular necrosis of the left hip in
Crohn's disease treated with corticoids].
PMID- 9757265
TI - [Conventional digital radiology and development of the level of images].
PMID- 9757266
TI - [And if this was not one's profession. Their medicine to them, my medicine to
me].
PMID- 9757267
TI - [MRI and articular cartilage].
AB - Although plain films are fundamental for routine imaging of degenerative chondral
lesions, MRI is a promising tool of investigation for the articular cartilage.
Its modalities are still imprecise and debated, but, because of its
noninvasiveness, it is destined to be preferred over arthroCT. The small size of
the cartilage requires thin slices of less than 3-mm thick. The various features
of normal cartilage images must be well known. They depend on acquisition
parameters, zonal structure of the cartilage and numerous artifacts (partial
volume average, chemical shift, magnetic susceptibility, truncation, "magic
angle"). Fast SE images provide a good compromise between contrast and the signal
to-noise ratio. T2-weighted images take advantage of an arthrographic effect in
case of joint effusion. 3D GE images allow a more accurate evaluation with 1-mm
thick slices. In all sequences, adding of a fat-suppression presaturation
increases contrast between the cartilage and the surrounding structures. The
diagnostic accuracies of the different sequences and of MR arthrography are
discussed. Quantitative measurements of cartilage thickness and volume remain the
topic of clinical research.
PMID- 9757268
TI - [MRI study of the arterial ligament and the left pulmonary artery in the
preoperative staging of left upper lobe bronchial cancers].
AB - PURPOSE: To demonstrate that the ligamentum arteriosum is visible by precisely
oriented MRI. To demonstrate the predictive value of the ligament involvement for
left upper lobe cancer surgery. MATERIAL AND METHODS: Fifteen controls, age
matched with bronchial cancer patients, were studied to establish how the
ligamentum arteriosum could best be visualized on MRI. Visibility was optimal on
RASE T1-weighted sequences on the frontal and sagittal oblique planes (aorto
pulmonary window). Acquisitions were performed with a body coil, 7 mm slices, 480
mm Fov, on a Magnetom Expert, 1T Siemens machine. Forty five patients with left
upper lobe cancer underwent MRI investigation after CT had shown mediastinal
proximity of the left pulmonary artery and the tumor. They underwent surgery with
manual localization of the ligament at the beginning of the procedure. Findings
and operative decisions were compared with those of MRI, establishing its
predictive value. MRI defined the tumor-ligament and tumor first centimeters of
the left pulmonary artery (LPA) relationships. RESULTS: MRI ligamentum visibility
was about 87%. Ligament non-involvement on MRI (n = 23) was confirmed at surgery
in all cases (100% concordance). Involvement suggested on MRI was confirmed in 18
cases and surgery was impossible or unsatisfactory. There were four false
positives with successful surgery (8% false positives). CONCLUSION: When CT shows
left lobe cancers extending in the mediastinum towards the LPA, precisely
oriented MRI assesses surgical difficulty and resectability by demonstration
involvement of the ligamentum and the first two centimeters of the LPA.
PMID- 9757269
TI - [Hepatocellular carcinoma (HCC) observed in Abidjan: aspects and role of
ultrasonography].
AB - In this retrospective study, we define the localization and ultrasound
appearances of hepatocellular carcinomas observed in Abidjan. The study included
31 inpatients (23 males and 8 females), aged from 24 to 76 years (mean, 47.4).
All patients had serum alphafetoprotein dosage and 21 patients had cytologic
examination. Diagnosis was based on a high level of serum alpha-fetoprotein (>
500 ng/ml), with or without cytological proof. Tumor characteristics (size,
number, echogenicity, nodular or diffuse form) and associated extratumoral signs
were noted. Ultrasound identified 19 cases of small tumors (size < 5 cm), and 12
large tumors (size > or = 5 cm). The tumor forms were mostly nodular and multiple
(24 cases), solitary nodule (3 cases), diffuse or infiltrative (4 cases). The
liver was heterogeneous with hyperechoic tumoral nodules (16 cases), hypoechoic
tumoral nodules (5 cases), hyperechoic and diffuse form (4 cases), and 2 cases of
mixed form. We have noted a particular form in 4 cases represented by a
heterogeneous liquid-like mass simulating tropical abscesses. Ascites (12
patient) was the most common extratumoral sign. Portal vein invasion or thrombus
was rare (3 patients). Of the 31 patients, ultrasound was abnormal in all cases,
alpha-fetoprotein test was positive in 12 cases (57.14%) and negative in 9 cases
(42.8%). Cytological test was positive in 17 cases (80.95%), and negative in 4
cases (19.04%). Alphafetoprotein and cytologic tests were both positive in 8
cases and, nonconcordant in 13 cases; in 4 cases alphafetoprotein was positive
while cytological tests were negative and, in 9 cases alphafetoprotein was
negative while cytological tests were positive. Two negative tests were never
observed. In Abidjan, hepatocellular carcinomas are commonly small or large,
multinodular and hyperechoic tumors contrasting with the small nodular and
hypoechoic tumors usually reported in western series. Ultrasound associated with
cytologic examination, appears to us to be more usefulness than alphafetoprotein
dosage in the diagnosis of hepatocellular carcinoma.
PMID- 9757271
TI - [MRI in post-traumatic cerebral fat embolism].
AB - We report two cases of posttrauma cerebral fat embolism evaluated with MRI. Due
to sensitivity, MRI is the best examination for detecting focal abnormalities of
the grey or white matter. MRI helps to make the diagnosis in atypical cases and
allows assessment of both extension and course of the embolism.
PMID- 9757270
TI - [Single shot fast spin echo sequence MRI cholangiopancreatography].
AB - PURPOSE: To assess the value of single shot fast spin echo MR sequence (SS-FSE)
in the morphological analysis of the biliary tree and pancreatic ducts and to
compare its accuracy with other imaging methods. MATERIAL AND METHODS: 95
consecutive patients referred for clinical and/or biological suspicion of biliary
obstruction were explored with MR cholangiopancreatography (MRCP). All patients
were explored with a Signa 1.5 T GE MR unit, with High Gradient Field Strength
and Torso Phased Array Coil. Biliary ducts were explored with SS-FSE sequence,
coronal and oblique coronal 20 mm thick slices on a 256 x 256 matrix. Total
acquisition time was 1 second. Native pictures were reviewed by two radiologists
blinded to clinical information. In case of disagreement, a third radiologist's
judgement was requested. In 88 cases, MRCP results were compared with direct
biligraphy methods. RESULTS: In all cases, MRCP produced high quality images
without MIP or other post-processing methods. For detection of biliary tree
distensions, the concordance value of MRCP was over 91% (Kappa 0.82). For
detection of biliary tree and/or pancreatic duct obstruction, MR sensitivity was
100% and specificity 91%. The overall diagnostic concordance value of MRCP was >
or = 93%. Difficulties in MRCP were caused by functional diseases or benign
stenosis. MRCP accurately diagnosed all lithiasic obstructions starting from a
stone size of 3 mm. CONCLUSION: MRCP produces fastly high-quality images. As it
is totally safe, it can be proposed as a first intention method in
biliopancreatic duct explorations.
PMID- 9757272
TI - [Mesenteric lymph node cavitation disclosing celiac disease in adults].
AB - We report a case of cavitation of the mesenteric lymph nodes, an uncommon
complication of celiac diseases. Computerized tomography is the method of choice
for diagnosis and follow up after gluten free diet.
PMID- 9757273
TI - [Aberrant origin of the splenic artery].
AB - We report an incidental finding of an aberrant origin of the splenic artery
described here for the first time.
PMID- 9757274
TI - [Ameloblastic carcinoma. Apropos of a case].
AB - Ameloblastic carcinoma is an exceptionally rare odontogenic tumor. Ameloblastoma
is considered malignant if there is evidence of metastasis or histological
features of malignancy. Present classification of these tumors is debated.
Several authors use the term malignant ameloblastoma for tumours that metastasize
despite "benign" histological features whereas ameloblastic carcinoma is referred
to as a tumor with malignant histological features regardless of its metastatic
potential. We report a case of mandibular ameloblastic carcinoma with cervical
lymph node metastasis in a 70-year-old man, documented by MRI and CT. We discuss
current knowledge on these tumors.
PMID- 9757275
TI - [What is it? The periportal halo sign in primary biliary cirrhosis].
PMID- 9757276
TI - [Recurrent chronic multifocal osteitis in children].
PMID- 9757277
TI - [Pulmonary embolism: the radiologist on the alert].
PMID- 9757278
TI - [Iodinated contrast media].
PMID- 9757279
TI - [Does a universal strategy of acute pulmonary embolism diagnosis exist today?].
AB - In this review, we demonstrate that there is no universal diagnostic strategy for
non-severe acute pulmonary embolism. The first part of the article is devoted to
the concept of thromboembolic disease: its frequency, severity and diagnostic
difficulties. The second part analyzes the tools used for diagnosis of pulmonary
angiography, noninvasive venous studies, and helical CT angiography. The last
part discusses current diagnostic algorithms for pulmonary embolism and the
changes that may be introduced by the use of helical CT in clinical practice. The
potential for MR imaging id discussed.
PMID- 9757280
TI - [Comparative value of MR-angiography, helical CT and digital angiography in the
preoperative assessment of abdominal aortic aneurysms].
AB - PURPOSE: To compare helical CT with MR angiography in pre-operative assessment of
abdominal aortic aneurysm (AAA). MATERIAL AND METHODS: Twenty patients with AAA
underwent helical-CT, MR-angiography and digital angiography. All exams were
interpreted independently by two groups of observers. Kappa and rho were
calculated to assess correlations. Sensitivity and specificity were calculated to
compare each method with the "gold standard" digital angiography. RESULTS: Inter
observer correlation was excellent. There was a very good agreement between both
methods in the assessment of the maximal diameter and the proximal neck of the
aneurysm. There was no significant difference in the assessment of stenoses of
the visceral and iliac arteries, the number of renal arteries, and iliac
extension. CONCLUSION: Helical CT and MR angiography are equivalent in pre
operative assessment of AAA.
PMID- 9757281
TI - [MRI semeiology of segmental contraction abnormalities in arrhythmogenic
dysplasia of the right ventricle].
AB - The diagnosis of localized arrhythmogenic right ventricular dysplasia may be
difficult to ascertain. Aside from electrophysiological arguments, visualization
of an abnormal right ventricular contraction pattern is of crucial importance for
diagnosis. Cine-MR is almost the only examination method which offers detailed
informations on the right ventricular contraction pattern. Nine observations of
segmental right ventricular contraction abnormalities assessed by cine-MR are
described here: dyskinesia of the distal part of the anterior wall (2), of the
inferior wall (2), of the right ventricular outflow tract (2); akinesia of the
outflow tract (2) and of the inferior wall (1). Morphological abnormalities of
the right ventricle are always associated with contraction abnormalities but seem
to be less disease specific. Patients should be more readily referred for a cine
MR examination when the diagnosis of localized right ventricular dysplasia is
suspected. Cine-MR sequences related to these observations may be reached via
Internet at:http:@alsace.u-strasbg.fr/cardio/coeur.htm.
PMID- 9757282
TI - [Ultrasonography of dorsal elastofibroma. Apropos of 6 cases].
AB - Elastofibroma dorsi is a benign soft-tissue tumor. Its sub- and pre-scapular
location and its appearance on CT and MRI generally lead to the diagnosis. We
have analyzed with sonography 6 elastofibromas in 4 patients; the diagnosis was
confirmed with CT scan or MRI. Some sonography imaging features supported the
diagnosis of elastofibroma dorsi. In all the cases, (1) the tumor occurred
typically in a sub- and pre-scapular location, and (2) showed a streaky
echostructure (3). A similar symptomatic or asymptomatic mass in the opposite
subscapular location is highly suggestive.
PMID- 9757283
TI - [Inflammatory pseudotumors of the liver. Apropos of a pediatric case with
radiological and ultrasonographic features and anatomopathological correlations].
AB - Inflammatory pseudo-tumor of the liver (IPT) are benign encapsulated masses. IPT
or inflammatory myofibroblastic tumor is a myofibroblastic proliferation with
chronic inflammatory cell infiltration of unknown origin. A four-year-old girl,
with cutaneous flushing of the face and biological inflammatory syndrome was
referred for abdominal investigation. Ultrasound examination showed a 5-cm mass
located in the anterior segment of the right hepatic lobe. After abdominal CT
showing slightly vascular feature of this right hepatic mass, diagnosis was made
through percutaneous US-guided fine needle biopsy. Surgical resection was
performed and pathologic examination of the mass confirmed preoperative
diagnosis. Clinical outcome was good.
PMID- 9757284
TI - [Subcutaneous trochanteric bursitis: an unrecognized cause of peritrochanteric
pain revealed by imaging].
AB - We present four cases of subcutanea trochanterica bursitis (one involving both
sides). The bursitis was acute and inflammatory in two cases, chronic and
microtraumatic in one, asymptomatic in one and septic in the last case. The
acutely inflamed bursa may contain a blood effusion increasing the pain. CT and
MRI provide distinctive images for the diagnosis of these particular types of
periarticular diseases.
PMID- 9757285
TI - [Multiple calcified cerebral metastases revealing bronchial adenocarcinoma.
Apropos of a case].
AB - Calcified brain metastases are rare. They are unique or multiple. The primary
site is lung, breast, gastro-intestinal tract, uterine cervix, bone or may be
unidentified. It corresponds pathologically to an adenocarcinoma, a sarcoma or to
a squamous cell carcinoma. We report a case of multiple calcified brain
metastases discovered before primary tumour (bronchial adenocarcinoma), raising
the problem of differential diagnosis resolved by stereotaxic brain biopsy.
PMID- 9757286
TI - [Epidural air after closed thoracic trauma].
AB - We report a rare case of spontaneous pneumorachis (epidural air in the spinal
canal) after benign chest trauma without rib fracture or pneumothorax.
PMID- 9757287
TI - [Quid? Bilateral renal angiomyolipoma (AML) revealing Bourneville's tuberous
sclerosis (BTS)].
PMID- 9757289
TI - [News of the SIGU (Societe d'Imagerie Genito-Urinaire)].
PMID- 9757288
TI - [Contribution of Abdoscan in MRI cholangio-pancreatography and MRI urography].
AB - MR Cholangiopancreatography (MRCP) and MR Urography (MRU) are promising recent
imaging modalities. Oral magnetic particles (Abdoscan, Nycomed SA, Oslo, Norway)
is an oral negative contrast agent eliminating signal intensity of the gastro
intestinal tract thus improving image quality at MRCP and MRU.
PMID- 9757290
TI - [Radiology assessment: the European dimension].
PMID- 9757291
TI - [Economic assessment in radiology].
PMID- 9757293
TI - [Prenatal MRI of corpus callosum agenesis. Study of 20 cases with
neuropathological correlations].
AB - Twenty prenatal MR studies of corpus callosum agenesis were retrospectively
studied and compared with neuropathologic examinations (18) or postnatal imaging
(2). Corpus callosum agenesis were either complete (14) or partial (6). Positive
diagnosis was made in 19 cases/20. The diagnosis of "isolated" or "associated"
corpus callosum agenesis was assessed in 11 cases/15. MR depicted 15 of the 33
associated neurologic abnormalities. Prenatal MR is a valuable complementary
technique for the diagnosis of corpus callosum agenesis when sonography is
doubtful. MR could improve prognosis evaluation, since it enables depiction of
associated abnormalities, notably gyral abnormalities, posterior fossa
malformations, and intra-cranial cysts. MR images prove to be useful before
neuropathologic examinations.
PMID- 9757292
TI - [Ductal carcinoma in situ of the breast: role of imaging].
AB - The incidence of ductal carcinoma in situ (DCIS) has increased with the
widespread use of screening mammography. DCIS is often suspected when clustered
microcalcifications are evidenced on routinely performed mammography. High
quality mammographies are required and should be completed with magnification
views. Mammographic--pathologic correlations are described according to the new
classifications as well as unusual forms of presentation on mammography. Early
contrast enhancement in DCIS on dynamic MRI is reported and seems to be related
with angiogenesis. A wire localization procedure of non-palpable lesions has to
be performed and per-operative specimen radiography is mandatory. Stereotaxic
large core needle biopsy is a valuable alternative to surgical biopsy but a
multidisciplinary team approach is necessary and follow-up is recommended if no
excisional biopsy is done. Quality in the management of DCIS depends on the
coherence of the "multidisciplinary team".
PMID- 9757294
TI - [Primary epiploic appendicitis].
AB - Primary epiploic appendicitis include torsion and primary inflammation of
appendices epiploicae. These uncommon pathologies have been until present
exceptionally diagnosed before surgery. Clinical and biological features have a
small specificity. However, US and CT findings suggest the diagnosis. Our study
reports 6 cases.
PMID- 9757295
TI - [Contribution of fast-sequence three-dimensional MRI angiography with Gadolinium
injection in the evaluation of supra-aortic vessels].
AB - Sixty-nine patients with cervical atherosclerotic disease were evaluated by
Magnetic Resonance (MR) angiography using a coronal 3D gradient echo gadolinium
enhanced sequence. The image quality was evaluated for each artery and ostium on
MIP reconstructions. A comparison with conventional angiography was achieved in
27 patients. All MR examinations were assessable; a second injection was
performed in ten patients. All carotid bifurcations were visualized. The ostium
of the common carotid artery was not assessable in 44% of cases due to the
limited coverage. The evaluation of the posterior circulation was good in 90% of
cases. The agreement between MR angiography and conventional angiography was good
despite a tendency to overestimate moderate stenoses. Stenoses greater than 70%,
carotid occlusions and vertebral stenoses greater than 50% were correctly
detected.
PMID- 9757296
TI - [A rare etiology of abdominal calcifications: lithopedion].
AB - We report a case of a rare and particular cause of abdominal calcifications
represented by the lithopedion. We describe different radiologic appearances
observed by: abdominal plain film, echography and CT. It appeared to us that
abdominal plain film alone is sufficient for diagnosis and undertaking surgery.
Echography and CT are helpful, especially for complementary evaluation.
PMID- 9757297
TI - [Ganglion cyst of the cervical spine causing radiculopathy].
AB - A case of ganglion cyst of the cervical spine causing radiculopathy is presented.
This epidural mass is rare at the cervical level. Computed tomography suggests
the diagnosis by the postero-lateral position of the mass close to facet joint.
The trilobed configuration and the tissue characterisation of the cyst are well
documented on MRI.
PMID- 9757298
TI - [Recurrent stomal hemorrhage treated by transjugular intrahepatic portosystemic
anastomosis and embolization of stomal varices].
AB - Bleeding stomal varices is a rare complication of portal hypertension. We report
the case of a cirrhotic patient, with a history of colonic adenocarcinoma, who
had recurrent bleeding stomal varices. Treatment with transjugular intrahepatic
portosystemic shunt and stomal varice embolization was performed because failure
of medical treatment of portal hypertension and sclerotherapy. Twenty six months
later only one stomal hemorrhage was noted. This suggests that transjugular
intrahepatic portosystemic shunt and stomal varice embolization is effective in
case of recurrent bleeding of stomal varices.
PMID- 9757300
TI - [Computed tomography in the management of lymphomas].
PMID- 9757299
TI - [Quid. Aorto-caval fistula in abdominal aortic aneurysm with clotting of the
supra-aneurysmal inferior vena cava].
PMID- 9757301
TI - [Impact factor: what for?].
PMID- 9757302
TI - [Bibliometric index].
AB - The Institute of Scientific information has edited an index to evaluate the
diffusion of scientific articles. It is based on the fact that the more an
article is cited as a reference in other articles, the more it is considered to
be important, and the higher the coefficient attributed to the journal in which
it was originally published. The impact factor takes into account the average
number of times which a journal is mentioned for recent articles published in a
given year. This index is an attempt to quantify the notoriety of scientific
journal for all scientific medical specialties.
PMID- 9757303
TI - [Magnetic resonance angiography of the carotid artery: artifacts, anatomy,
diseases].
AB - Magnetic resonance angiography is now a technique commonly used in neurologic
practice. We give a brief overview of the biophysical principles of this
technique. Recent refinements and technical innovations are also noted. After
some anatomic considerations about the carotid artery, we provide some data about
the role of MRA in atherosclerotic and non atherosclerotic diseases (dissections,
aneurysms, arteritis, post operative follow-up...) of the extra and intracranial
carotid arteries. The purpose of this review is to concentrate on the role of
magnetic resonance angiography in patients with various carotid artery diseases
and to specify possibilities, limitations and risk of misinterpretation. Magnetic
resonance angiography is a major, still evolving technique.
PMID- 9757304
TI - [Study of cotyloid anteversion by coxometric measurement].
AB - A coxometric evaluation is helpful for the diagnosis and the prognosis of hip
dysplasia. These measurements also given an intrinsic guide to the surgeon for
total hip arthroplasty. A coxometric protractor is drawn on the majority of the
goniometers and allows the measurement of the angle of internal and external
roof, the angle of the acetabular roof obliquity and the femoral neck-shaft angle
on a hip AP X-ray. The purpose of this report is to demonstrate that on the same
X-ray, the adequate placement of the coxometric protractor allows to calculate
the inclination angle, the acetabular anteversion angles and the anterior roof
angle.
PMID- 9757305
TI - [Computed tomography of intrahepatic pancreatic pseudocysts].
AB - PURPOSE: Intrahepatic pseudocyst complicating pancreatitis is a rare event. The
goals of this paper are to report the computed tomographic (CT) features of
intrahepatic pseudocyst and to analyze the role of percutaneous puncture and
percutaneous drainage in the diagnosis and treatment of intrahepatic pseudocyst.
MATERIAL AND METHODS: Three cases of intrahepatic pseudocyst studied by CT were
retrospectively reviewed. Percutaneous puncture of the intrahepatic pseudocyst
was performed in two cases, and was subsequently followed by percutaneous
drainage of the intrahepatic pseudocyst in one case. RESULTS: In the three cases,
intrahepatic pseudocysts appeared like multiple, hypoattenuating, homogeneous
intrahepatic fluid collections, associated with intrahepatic bile duct dilatation
in one case. In the two cases in which it was performed, percutaneous puncture of
the pseudocyst revealed an elevated amylase level, thus confirming the diagnosis.
In one case, percutaneous puncture revealed superinfection, thus indicating
percutaneous drainage of the pseudocyst. CONCLUSION: The diagnosis of
intrahepatic pseudocyst should be suggested in the presence of pancreatic lesions
and a single or multiple intrahepatic fluid collections visible on CT. CT allows
percutaneous puncture of the pseudocyst to be done, thus confirming the diagnosis
and indicating subsequent performance of percutaneous drainage in complicated
cases.
PMID- 9757306
TI - [MRI and bladder leiomyoma].
AB - Unlike epithelial tumors, connective tissue tumors are uncommon, representing
only 3% of all bladder tumors. Leiomyoma of the bladder is the most frequent non
epithelial benign tumor of the bladder. Magnetic resonance imaging (MRI) is
highly useful for diagnostic purposes and to determine the degree of extension.
Only few reports of sonographic findings have been reported for leiomyoma of the
bladder. The tumor usually develops within the bladder. Extravesicular formations
have also been reported as well as a few intramural localizations. The
characteristic feature is the absence of mucosal involvement. We analyzed the MRI
findings in a case of leiomyoma of the bladder with intra and extravesicular
development, inflammatory reaction of the bladder wall and uterine adherences in
a woman with a past history of chronic cystitis. The role of diagnostic MRI is
discussed.
PMID- 9757308
TI - [Intracranial metal foreign bodies and contraindications of MRI. Apropos of a
case].
AB - We report a firearm wound of the brain which could not be analyzed by computed
tomography because of induced artifacts. MRI study was remarkably after verifying
the non-ferromagnetic nature of the projectiles.
PMID- 9757307
TI - [Renin-secreting tumor detected by MRI].
AB - We report an uncommon case of small renin secreting tumor of the kidney located
in the medulla. The tumor was primarily detected by MRI and subsequently studied
by spiral CT. The results and limitations of both techniques are discussed.
PMID- 9757309
TI - [Malignant melanoma of soft tissues. Apropos of a case].
AB - A case of malignant melanoma of the quadriceps tendon is reported. This is an
uncommon soft tissue sarcoma of melanocytic origin. The appearance on MRI depends
on its melanin content. The microscopic appearance is distinctive and prognosis
is poor. This tumor should be kept in mind when a nodular lesion is detected in
specific tendon or aponeurosis.
PMID- 9757310
TI - [Quid? Hepatic distomatosis at the invasive phase].
PMID- 9757311
TI - [Slice thickness of spiral CT images as function of pitch].
AB - This report comments on several measures of effective slice thickness. In
particular, the full width at half maximum FWHM of the slice sensitivity profile
is discussed. An analytical approximation between FWHM and the pitch p is
established. Values of FWHM are compared as a function of pitch from the
approximate formula, from an empirical formula, from an exact calculation and
from measurements. In addition, the approximation for the full width at tenth
maximum is also given and is compared with exact calculations. The main results
of this investigation is that the analytical formulae, although approximate, are
sufficiently precise and easy to use.
PMID- 9757312
TI - [Meningeal hemangiopericytomas. A retrospective reciew of 20 cases].
AB - BACKGROUND AND PURPOSE: Meningeal hemangiopericytomas (MHP) account for 2% of
meningeal tumours. Clinical features, radiology findings, therapy and outcome of
20 MHP operated in our department from 1965 through 1995 were analyzed to
determine presurgical features for diagnosis, histologic diagnostic criteria and
the role of adjuvant post-operative radiotherapy. METHODS: In conformity with the
new WHO classification which differentiates MHP from meningiomas, 20 patients
with tumors compatible with this definition were reviewed. RESULTS: The clinical
features differed slightly from meningiomas. Only epidemiologic data were
different. The CT and MRI scanning gave no preoperative distinction between MHP
and meningiomas. Angiography played a predominant role in this distinction. The
20 patients were operated. Twelve received post-operative radiotherapy. The rate
of local recurrency was 45%. Of these, 88% did not receive radiotherapy post
operatively. Two patients (10%) presented late recurrence and three patients
(15%) one or more extra-neural metastases. Two patients received radiosurgical
treatment. In one case with disseminated metastasis, chemotherapy was used
without success. Three patients died during the follow up. CONCLUSION:
Considering our review and the current literature, it seems that complete
excision followed by adjuvant radiotherapy of more than 50 Gy significatively
reduces the risk of recurrence (p < 0.0001). Radiosurgery is indicated for
recurrent tumors measuring less than 30 mm in their greatest diameter.
PMID- 9757313
TI - [Primary central nervous system lymphomas. Diagnostic and prognostic effect of
steroid-induced remission].
AB - PURPOSE: Non-AIDS primary central nervous system lymphomas may respond totally or
partially to corticosteroids. These corticoid-induced remissions seems to be very
specific for this disease. They have been proposed as diagnostic test. The effect
of these remissions on prognosis remains unknown. METHODS: A retrospective study
was conducted. Corticosteroid sensibility, duration of survival, duration of
disease free interval and type of treatment were compared between two groups of
patients. The first one (group 1) included 44 patients in which exact diagnosis
was made by stereotactic biopsy or surgery. The second group (group 2) included 5
patients exhibiting typical neuroradiological aspects of primary lymphoma in whom
corticosteroid therapy produced a total regression of the lesions. RESULTS: In
group 1, 29.1% of the lymphomas exhibited cortico-sensitivity. Duration of free
interval of disease accounted for 75% of the overall duration of survival. Age
was the only significant factor predicting remission (p = 0.019). The sole factor
influencing total duration of remission was the type of treatment (p = 0.03).
Duration of remission was significantly shorter in group 2 versus group 1
patients (p = 0.007). CONCLUSIONS: Duration of the first remission is of
paramount importance on survival as well as the quality of first line therapy. In
these conditions the absence of precise diagnosis due to corticoid-induced
remissions could be dramatically deleterious.
PMID- 9757314
TI - Ki-67 antigen expression as a prognostic factor in primary and recurrent
astrocytomas.
AB - BACKGROUND AND PURPOSE: Histological grading is widely used to evaluate the
prognosis for patients with astrocytic tumors. Many complimentary methods have
been introduced, such as proliferation markers in order to better assess the
proliferative potential of these gliomas. METHODS: Archival, paraffin embedded
specimens of recurrent astrocytic tumors of varying grades from 22 patients were
examined using antibodies against Ki-67 (MIB-1). Labeling indices (LI) were
analyzed at the first and second operations and compared with tumor grades, age
of the patients and the time between the operations as well as the survival time.
RESULTS: There was a progression of malignancy between the operations. Dividing
Ki-67 labeling indices in < or = 10% vs. > 10% significantly separated parameters
such as the time between the first operation and relapse as well as the
cumulative proportion of survival. The proliferation fraction was an independent
prognostic factor. CONCLUSION: Assessment of Ki-67 LI is highly recommended in
addition to histology in evaluation of the malignancy potential of astrocytic
tumors.
PMID- 9757315
TI - [Seizure-linked hippocampal plasticity and protection against excitotoxicity:
possible role of neuropeptide-y].
AB - BACKGROUND AND PURPOSE: Changes occurring in neuropeptide-Y immunoreactivity
after kainic acid injection in rats and their possible consequences on seizure
brain damage were studied. METHODS: First, an intra-hippocampal kainic acid
injection was performed (n = 7), inducing an ectopic and bilateral neuropeptide-Y
immunoreactivity in mossy fibers. On the side of the injection, this neuropeptide
Y staining was associated with dramatic neuronal loss whereas, in the
contralateral hippocampus staining was observed without associated neuronal loss.
The CA3 a-b pyramidal cell loss induced by an intra-ventricular kainic acid
injection was then compared between a control group (n = 6) and a pre-conditioned
group (n = 6) characterized by neuropeptide-Y staining in the mossy fibers
obtained by a previous contralateral intra-hippocampal kainic acid injection as
described. RESULTS: In the pre-conditioned group, the CA3 a-b pyramidal cell loss
was significantly lower (m = 33.5%) than in the control group (m = 86.6%). The
neuropeptide-Y inhibiting the pre-synaptic release of glutamate, glutamate
related epileptic-brain damage could be reduced when neuropeptide-Y is expressed
by granulated cells. IN CONCLUSION: Seizure-linked plasticity could induce a self
protection phenomenon against excitotoxic lesions possibly partially mediated by
de novo neuropeptide-Y mossy fiber expression.
PMID- 9757317
TI - [Trauma-induced arterial aneurysm in childhood. Report of a case and review of
the literature].
AB - We report a case of calloso-marginal artery aneurysm in a 3 year old child,
revealed 3 weeks after a craniocerebral trauma with frontal embarrure, by a
sudden subarachnoidal hemorrhage syndrome with loss of consciousness and coma.
The CT scan confirmed the subarachnoid hemorrhage in all the basal cisterns, with
an interhemispheric subdural hematoma. The carotid angiography showed a right
calloso-marginal aneurysm. The child has been operated (coagulation of the artery
and excision of the false aneurysm. We studied the mechanism of pediatric post
traumatic aneurysm, the histological and clinical presentation emphasizing the
necessity of a complete neuroradiological exploration when new neurological
symptoms develop after head trauma. Neurosurgical and/or endovascular
neuroradiological treatment is mandatory.
PMID- 9757316
TI - [Extracranial trigeminal schwannomas with middle temporal fossa development].
AB - Schwannomas of trigeminal nerve account for 0.07% to 0.36% of all intra-cranial
tumors. We report three observations about Jefferson's type D tumors, mainly
extra-cranial with only small intra-cranial extension, concerning two men and one
woman, who were respectively 36, 60 and 63 years old. Two of them presented with
facial pain and hypoesthesia in the same territory. The third one developed a
diplopia. In all cases, CT scanner analysis evidenced a large hypodense tumor
extending in the infratemporal fossa. Temporal lobe and cavernous sinus were
pushed aside by the intra-cranial extension. Tumors were hypo intense in T1
weighted image with significant enhancement after gadolinium injection. One of
the tumors was a cystic form and in that case, an hyper signal in T2-weighted
image was detected in the middle of the lesion. A combined subtemporal and
transmaxillary approach was performed in 2 cases. In the third case, the removal
of the tumor was only performed by a transmaxillary approach. In this series,
there was no surgical mortality. One patient presented a postoperative residual
painful anesthesia. In conclusion, extra-cranial schwannomas with intra-cranial
extension are specially rare lesions. The most common early symptoms are facial
neuralgia, facial hypoesthesia or diplopia. Neuroradiologic investigations,
including CT and MRI evidence the precise anatomic site of the lesions. With the
help of these techniques, total surgical tumor removal is possible in the
majority of cases.
PMID- 9757318
TI - [Combination treatment for pilocytic astrocytoma: stereotaxic radiosurgery and
endocavitary radiotherapy].
AB - The treatment of a pilocytic astrocytoma located in a functional area can be
performed using radiosurgery. We report a 7 year old male, right-handed, who
presented with a pilocytic astrocytoma in the left parieto-occipital lobe. After
a 7 year follow-up, the tumor became symptomatic (partial and generalized
seizures). The CT scan and nuclear magnetic resonance imaging revealed an
increased size of the mural tumor and the development of a cystic component.
Multi-beam irradiation of the tumor (dose of 30 Gy at the center with 21 Gy on
the isodose 70%) was performed with a LINAC for radiosurgery coupling a modified
Saturne 18 MeV linear accelerator and a Talairach stereotactic frame. Following
multi-beam irradiation, the increase in size of the cyst imposed further
intracavitary radiation using Rhenium 186 (186Re) to deliver 400 Gy to the cyst
wall. After a period of intense cerebral edema, resolutive with steroid
treatment, we obtained progressive cyst disappearance and mural nodule
retraction. A PET scan, performed 3 years after this treatment, revealed no
metabolic activity in the persistent mural nodule. The patient remains totally
asymptomatic.
PMID- 9757319
TI - [Guide-lines for head injured patients management in adult age. Neurosurgical
Society of France].
PMID- 9757320
TI - [The development of neurosurgeons in France and accreditation].
PMID- 9757321
TI - [Development of the corpus callosum (CC)].
AB - Corpus callosum embryology can be divided into three parts: during
"commissuration", a cellular mass develops between the two telencephalic
vesicles. The primitive lamina terminalis corresponds to the closing point of the
anterior neuropore. Its dorsal part grows and forms the lamina reunions (6-8
intra uterine weeks, IUW). From ventral to dorsal, this lamina reunions gives
rise to the area praecommissuralis (origin of the anterior commissure), to the
primordium hippocampi (10 I.U.W., fornix), and to the massa commissuralis (10
S.I.U., corpus callosum). Fibers arising from the developing hemispheres run
through this primitive corpus callosum. The growth of the corpus callosum follows
the expansion of the hemispheres, in a rostro-caudal and then dorso-ventral
circular movement. The last part of the corpus callosum to form is the rostrum.
Maturation occurs postnatally, and corresponds to axonal elimination, and
myelination, progressively changing the callosal connection pattern of the
newborn and infant into the adult pattern.
PMID- 9757322
TI - [Morphologic anatomy of the corpus callosum].
AB - The corpus callosum is a neopallial commissure. In inferior vertebrates, the
pallial commissures are essentially represented by the anterior commissure. The
corpus callosum appears in mammals only. Eutherians alone have a corpus callosum,
the other mammals have an anterior commissure and hipocampal commissure. In
humans, the different portions of the corps callosum are described on a median
sagittal slice: rostrum, genu, body, isthmus, splenium. Klingler method allows to
dissect fibers of each of these portions and their relationship with the corona
radiata and optic radiations. These latter are separated from the ventricular
ependyme by callosal radiations. Finally, each part of the corpus callosum
participates in lateral ventricle wall formation.
PMID- 9757324
TI - [Anatomic MRI study of commissural agenesis and dysplasia of the Telencephalon
(Agenesis of the corpus callosum and related anomalies). Clinical correlations
and morphogenetic interpretation].
AB - A series of 78 patients presenting with agenesis of the cerebral commissures and
properly investigated with MR imaging, was reviewed and analyzed morphologically.
Results were compared with descriptive data from the literature, and with the
developmental models proposed. From this, a model of a-commissural brain is
described: the lamina terminalis would be homologous to a telencephalic anterior
medullary velum of which the commissure would be the anterior commissure, and the
lamina of white matter described as the Probst's and the fornical bundles, would
be homologous to a posterior medullary velum having become a medial medullary
velum due to the division of the prosecephalon into two cerebral hemispheres, and
of which the commissure would be the (posterior) calloso-hippocampal commissure.
Also, the comparison with the model establishes that in the actual malformations,
defects of the cingulum and of at least some of the intralobaroccipital
association bundles are observed beside the commissural defect. Such a model
would reclassify these disorders, distinguishing the "simple" commissural
defects, complete or segmental, global or dissociated, without or with a
ventricular expansion, from more complex forms with multicystic defects, adding
major dysplastic lesions of the dura mater, leptomeninges and parenchyma, to the
commissural defects. Paradoxically, the latter group seems to be clinically less
severe than the "simple agenesis" group, of which prognosis (including the
neurologic and intellectual disorders as well as the associated pathologies) is
generally very poor; this should be seriously considered since the antenatal
diagnosis of these malformations is made routinely with ultrasonography and MRI.
PMID- 9757323
TI - [Arterial and venous vascularization of the corpus callosum].
AB - Blood supply of the corpus callosum is assured by two arterial systems, the
carotid system mainly and the vertebrobasilar system accessorily. The carotid
system intervenes via the pericallosal artery, portion of the anterior cerebral
artery distal to the anterior communicating artery. This pericallosal artery can
be bihemispheric in 4 to 12% of the cases or azygos in 0.26% of cases. In 20 to
80% of cases, the median callosal artery arises from the communicating artery.
The vertebrobasilar system intervenes in splenium vascularization by its terminal
branches. These two carotid and vertebrobasilar systems give rise to perforating
arteries that assure intrinsic vascularization of the corpus callosum creating a
system of regular vascular stitches around the fibers of the corpus callosum. The
venous drainage of the corpus callosum is essentially via callosal veins and
callosocingulate veins towards the deep venous system of the brain.
PMID- 9757325
TI - [Histogenesis of the corpus callosum].
AB - The corpus callosum results from neocortical commissural axon fasciculation. Its
development reflects the interhemispheric circuitry and then follows the
successive steps of synaptogenesis. The first stage consists of callosal neuron
differentiation, which allows the extention of the future callosal axon; this is
an early event that occurs while neuronal migration to the cortical plate is
still ongoing. Callosal axon guidance towards its specific target is the second
step which includes reaching and crossing the midline and further target
recognition with formation of initial synapses. This period extends from 12 to 22
post-conceptional weeks and corresponds to the following histological features:
i) progressive invasion by callosal growth cones of the dorsal part of lamina
reuniens through a preformed glial pathway; ii) appearence of the three parts of
corpus callosum, namely truncus, rostrum and lastly the splenium. Both these
stages are genetically controlled either directly by developmental gene
expression (neurogenesis genes) or indirectly by the establishment of cue maps
(spatial expression of extra-cellular matrix proteins). The third step is that of
synapse remodeling by synaptic activity, giving rise to axonal elimination,
macroscopically revealed by a transitory thinning of corpus callosum. This
perinatal event contributes to the corpus callosum acquiring a mature topography.
Finally, analysis of corpus callosum ontogenesis appears as a striking model of
synaptogenesis study and provides physiopathological assumptions for a
understanding of the corpus callosum agenesis.
PMID- 9757326
TI - [Agenesis of the corpus callosum. Neuropathologic study and physiopathologic
hypotheses].
AB - The neuropathological study of corpus callosum agenesis requires a two-phase
approach: first it should analyze the putative causal factors, i.e. absence of
callosal neurons, commissuration inability or synapse remodelling defect;
secondly it has to detect any morphogenetic effects stemming from the absence of
commissure such as nonregression of archicortical structures, ventricular
enlargement or possible invasion of the remaining telencephaplic commissure by
callosal neurons. Absence of callosal neurons due to abnormal corticogenesis
gives rise to corpus callosum agenesis without callosal axon, that is without
Probst's bundles. Conversely, corpus callosum agenesis occurring secondary to a
commissuration default is associated with the presence of callosal axons which
travel along the midline instead of crossing, that leads to the formation of
Probst's bundles. This inability to cross the midline could be secondary to an
obstacle, such as lipoma or as interhemispheric cysts, or primitive due to axonal
guidance disturbance. In the latter situation, the commissural defect could
affect the other cerebral commissures i.e. anterior or hippocampal commissures,
or could become integrated into a more diffuse midline pathology involving both
cerebral and extracerebral structures. Finally, it could be assumed that a
synapse remodelling defect could lead to atrophy or hypertrophy of the
commissure, that occurs in the absence of white matter pathology.
PMID- 9757327
TI - [Prenatal diagnosis of anomalies of the corpus callosum with ultrasound: the
echographist's point of view].
AB - Ultrasonography can identify agenesis of the corpus callosum (excluding
holoprosencephaly which an be detected earlier on) in the second trimester of
pregnancy (18-20 weeks gestation). Diagnosis of corpus callosum agenesis is
difficult but is important as a risk factor for neurological or genetic
malformations. The characteristic signs suggestive of corpus callosum agenesis
are: moderate distension of the occipital ventricle and the ventricular
communications; absence of the spectrum giving rise to an upward displacement of
the third ventricle shown in the anterior coronal section (especially in
transvaginal ultrasonography); radial position of the fissures on the internal
side of the cerebral hemisphere seen on the sagittal section; the absence in
color coded Doppler of the pericallosal artery normally characterised by a
semicircular vessel observable on the median sagittal section. At present, color
coded Doppler should give the diagnosis of corpus callosum agenesis. MRI can
provide further information especially in case of late detection around 28-30
weeks gestation as is most frequently the case. The development of 3D echographic
imaging should allow an even more sophisticated approach to this diagnosis giving
even more precise prognosis. Isolated corpus callosum agenesis is compatible with
normal intellectual development an raises an important problem with regard to
pregnancy continuation and infant development. Each individual case should be
discussed during the pluridisciplinary prenatal diagnostic discussion.
PMID- 9757328
TI - [Obstetrical management of agenesis of the corpus callosum].
AB - We present a multicenter analysis of 24 cases of prenatal diagnosis of corpus
callosum agenesis and review the literature concerning prognosis factors for
continuing or interrupting pregnancy.
PMID- 9757329
TI - [Prognosis of isolated agenesis of the corpus callosum].
AB - We report preliminary results of a three year follow-up of ten children affected
with apparently isolated corpus callosum agenesis (prenatal diagnosis). This
population was collected from a multicenter prospective study: annual survey
included physical examination, developmental outcome and psychometric evaluation.
Febril convulsions appeared to be more frequent than in the general population;
developmental outcome was normal at the last evaluation. Follow-up has to be
performed up to 10 years to determine more accurately prognosis of isolated
corpus callosum agenesis.
PMID- 9757330
TI - [Genetics of agenesis of the corpus callosum].
AB - Agenesis of corpus callosum (ACC) is one of the most common brain malformations
observed in humans. It is a heterogeneous malformation, with many etiologies.
Isolated ACC is usually sporadic but familial cases have been reported. ACC can
complicate numerous polymalformative, either monogenic or chromosomal syndromes.
In some of them, for example Aicardi syndrome, Anderman syndrome or acrocallosal
syndrome, ACC is a mandatory manifestation. Further identification of the
molecular bases of these syndromes will be helpful in understanding the causal
heterogeneity of this malformation.
PMID- 9757331
TI - [Corpus callosum disconnection syndromes and functional organization or the
corpus callosum in adults].
AB - Knowledge concerning the role of the corpus callosum derives from the study of
patients with lesions of spontaneous or surgical origin. Three major aspects are
defined: interhemispheric elementary transfer of symmetrically organized
messages, complex transfer of asymmetrically organized information,
interhemispheric transfer and complex behaviors. Symptoms are both complex and
rather limited; they can be missed if they are not specifically searched for.
PMID- 9757332
TI - [Corpus callosum syndrome in children].
AB - The survey of callosotomized children is a difficult because they often present a
severe epilepsy with mental retardation. The younger the child, the better he
recovers. The child can be considered as a physiological split-brain. If one
compares commissurotomized children with those presenting an agenesis of the
corpus callosum, the later ones have, to a certain extent, an interhemispherical
transfer which suggests supportive ipsilateral or sub-cortical connections.
PMID- 9757333
TI - [Interhemispheric transfer and agenesis of the corpus callosum. Capacities and
limitations of the anterior commissure].
AB - In case of agenesis of the corpus callosum, four hypotheses may be proposed to
explain how compensation of the interhemispheric transfer might take place. These
hypotheses include the use of cross-cueing behavioral strategies, the bilateral
representation of speech-functions, the increased use of ipsilateral sensory
motor pathways, and the use of noncallosal commissures. Among all these
compensatory mechanisms, the last one, namely the increased use of the anterior
commissure, is the most significant. It can easily explain that acallosal
patients with an anterior commissure (which can be increased in size), have
better results in interhemispheric transfer tests, and in neuropsychologic tests,
than patients having no anterior commissure. However, the anterior commissure
alone, even increased in size, cannot normalize all the interhemispheric transfer
tests, because of the big difference between the field of origin of the callosal
fibers, and the field of origin of the anterior commissure fibers.
PMID- 9757334
TI - [Acquired lesions of the corpus callosum].
AB - Acquired lesions of the corpus callosum may be related to tumoral, vascular,
traumatic or degenerative disorders and, one must not forget, can result from
surgical access. Currently, the quality of neuroimaging enables a validation or
precision of anatomoclinical, neuropsychological and neurophysiological
correlations established from experimental and/or autopsy data. However the
"specific" signs of acquired lesions of the corpus callosum are often quite
complex and may be readily overlooked or masked within a heterogeneous clinical
presentation due to more or less important associated lesions of neighboring
structures. Therapeutic management (tumors, arteriovenous malformations,
cavernomas) depend on the nature and the extent of the lesion more than the
functional nature of this inter-hemispheric commissure with an exceptional
functional plasticity, particularly when the lesion is limited.
PMID- 9757335
TI - [Lipoma of the corpus callosum].
AB - In the central nervous system, 40% of all lipomas develop in the anterior third
of the corpus callosum. In 48% of the cases, there is partial agenesia of the
corpus callosum. In 50% of the cases, there is no clinical expression. In cases
with epilepsy, surgery has no effect on seizures and is difficult due to the
arterial relations.
PMID- 9757336
TI - [Surgery and epilepsy].
AB - Corpus callosotmy was introduced in 1940 as a palliative treatment for
generalized epilepsies. The improvement of the surgical technique, and the
simplification of the initial "total commissurotomy" made that procedure proposed
in order to decrease the frequency and the severity of the seizures occurring in
the secondary geralzed epilepsies. However the indication criteria remain
unclear, due to the difficulty for analysing the results and the feterogenity of
the series. A careful selection requiring a comprehensive epilepsy team remains
mandatory despite the relative simplicity of the procedure.
PMID- 9757337
TI - [Surgical approaches to the corpus callosum].
AB - There are no dedicated approaches to the corps callosum itself. The different
approaches, subcallosal, supracallosal and posterior to the splenium are usually
used to reach neighboring structures such as third ventricle or pericallosal
arteries. MRI is the best guideline to reach a specific position in the corps
callosum and must imperatively contribute to the choice of the type of approach.
During the procedure, it is necessary to take great care to protect the vessels,
arteries and veins especially, to avoid ischemic damage which is the main
complication of these approaches.
PMID- 9757338
TI - [Tethered cord syndrome in adults].
AB - A series of 25 adult patients surgically treated for a tethred cord syndrome is
reported. Preoperatively 19 patients presented with a sensorimotor deficit in
their lower limbs, 17 with sphincter disturbances, 12 with pain and/or
neuroorthopedic symptoms and 9 with cutaneous lumbar anomalies. At surgery, an
isolated anomaly (lipoma, anomalous or adherent filum terminale) was disclosed in
18 patients. In the remaining 7, a more complex form of dysraphism was disclosed.
Follow-up ranges from 3 months to 20 years (mean: 6.5 years). Ten patients
improved, 6 were stabilized and 9 showed continuous worsening. The best results
were obtained in patients in whom the cord tethering resulted from an anomalous
filum terminale. Results were significantly worse in patients suffering long
standing symptomatology and showing either radiologically or surgically mixed
mechanisms of cord tethering. Early surgical correction should be idealy
undertaken in patients suffering from minor neurological deficits and in whom
magnetic resonance imaging illustrates a low conus medullaris attached by a short
thickened filum terminale.
PMID- 9757340
TI - [Presurgical evaluation of cerebral tumors with functional MRI].
AB - PURPOSE: To evaluate the capabilities and the limitations of motor functional
magnetic resonance imaging (FMRI) in the presurgical planning of the cerebral
tumors located in or near the motor homunculus and to correlate each type of
activation with the histologic characteristics of each tumor. MATERIALS AND
METHODS: FMRI was performed in 17 patients (14 adults and 3 children), without
motor deficit, presenting with various intra cerebral tumors. Three FMRI
activation paradigms were used, controlateral to the lesion: ballistic opposition
of the fingers, flexion-extension of the foot and click of the tongue. Four
patients, without motor deficit, with cerebral tumors far from the motor
homunculus were used as control group to look for non specific activations. In
all cases, the histopathology of the tumor was known accurately. RESULTS: In 11
patients with infiltrating tumors, the activated areas were clearly displaced.
They were often intratumoral and scattered in correlation with the degree of
infiltration. Two patients with non infiltrating tumors (meningioma) showed
extratumoral shift of the activated areas. Four patients presenting cerebral
tumors far from the homunculus motor did not show intratumoral activation. The
supplementary motor area and the ipsilateral primary motor cortex were also
sometimes activated during the motor tasks. The task of the tongue was often
artifacted, probably because of the head motion. CONCLUSIONS: These preliminary
results suggest that the histopathologic characteristics of a tumor and
especially its microscopic structure plays a role, with others factors, on the
motor functional area organization. In a small number of cases, the data obtained
from the FMRI could be used intraoperatively, with a neuronavigation system.
PMID- 9757339
TI - [Therapeutic strategy for cerebral arteriovenous malformations. Proposal for
classification of individual hemorrhagic risk].
AB - BACKGROUND AND PURPOSE: Therapeutic strategy for the cerebral arteriovenous
malformations (cAVM) is mainly based on the assessment of hemorrhage risk. This
risk is estimated between 2 and 4% according to various series. However, this is
a collective risk projected upon a given population. To improve therapeutic
strategy for cAVM, we propose a grading of the individual hemorrhage risk based
on 5 angiographic parameters: 4 are increasing risk factors and one is a
favorable index. METHOD: This grading system has been achieved by univariate then
multivariate analysis by logistic regression from angiographic data of 250
consecutive patients with cAVM. Thirty angiographic parameters were studied.
RESULTS: Grade I has no risk factors and has two subgrades: Ia with venous
recruitment (which is the lonely favorable parameter), Ib without venous
recruitment. Grade II is the presence of venous stenosis or venous reflux. Grade
III is the presence of exclusive deep venous drainage. Grade IV is the presence
of intra or juxta-nidal aneurysm. There were 13% of hemorrhage in grade Ia, 38%
in grade Ib, 48% in grade II, 90% in grades III and IV. CONCLUSIONS: This model
can be helpful for the treatment decision making and also contributes to a better
understanding of the natural history of cAVM. It must be further confirmed by a
prospective study.
PMID- 9757341
TI - [Use of the CCD (Sofamor-Danek) rod plates for instabilities of the craniospinal
junction].
AB - We report our experience with the CCD material (Sofamor-Danek) for the treatment
of cranio-cervical instability. In this method, rod-plates are fixed to the
occipital bone and to the cervical spine with hooks. This technique is mainly
indicated for the treatment of patients with severe osteoporosis or with
significant thinness of the occipital bone. Four cases are presented. Three of
them suffered from a inflammatory rheumatism. The fourth patient had been
previously treated by an occipito-cervical fixation with a Roy-Camille plate for
a C2 metastasis and presented a failure of the occipital screws fixation. In all
cases, no post operative complications were observed and all patients had a
significant improvement of their cervicalgia. We confirm the interest and the
fiability of the CCD method which has simplified the procedure and is specially
suitable for the treatment of all types of cranio-cervical instability, even in
the most adverse conditions.
PMID- 9757342
TI - [Subarachnoid hemorrhage syndrome and its aneurysmal etiology. From Morgagni to
Moniz, Dott and Dandy. A historical overview].
AB - Although obvious today, the concept of subarachnoid hemorrhage due to ruptured
intracranial aneurysms emerged slowly in medical knowledge with the clinical and
pathological observations of many perspicacious authors beginning with Morgagni
in the middle of the eighteenth century. This body of clinical material made it
possible for Symonds in 1924 to affirm this concept on clinical and pathological
grounds just a few years before Egas Moniz performed the first cerebral
angiograms and such pioneers as Norman Dott and Walter Dandy the first direct
attacks on cerebral aneurysms.
PMID- 9757343
TI - [The retro-auricular, transmastoid, infralabyrinth approach. A simple route for
excision of tumors of the jugular foramen].
AB - BACKGROUND: The jugular foramen is a complex area of the skull base. Its
contents, the anatomical relationships in the region, and its location at the
skull base, are responsible for problematic surgical approaches. The classical
infratemporal surgical routes remain complex and difficult to perform. The
lateral approach through a mastoidectomy is almost always associated with an
anterior transposition of the facial nerve although that transposition is usually
unnecessary. METHODS: Progressive drilling along the sinusojugular axis, inferior
to the labyrinth and medial to the third portion of the facial nerve, combined
with a simple neck dissection, allows the surgeon to nicely expose the jugular
foramen. The surgical procedure is described, following a brief anatomical
reminder of the essential relationships in the area. A clinical observation is
used to illustrate the purpose. RESULTS: Most schwannomas of lower cranial nerves
and small glomus jugulare tumors should be resected using this approach, which is
a simplified lateral approach, without post operative facial palsy or cophosis.
CONCLUSIONS: The infralabyrinthine approach is a simple way to expose the jugular
foramen region compared with infratemporal complex and time-consuming approaches.
PMID- 9757344
TI - [A peculiar mechanism of hydrocephalus: the "water-hammering" effect].
AB - BACKGROUND AND PURPOSE: Aneurysms of the basilar artery can cause hydrocephalus
due to compression of the third ventricle or the sylvian aqueduct. The
observation of a particular case led to discuss another possible mechanism of
hydrocephalus. CLINICAL PRESENTATION AND RADIOLOGICAL STUDIES: An aneurysm of the
basilar artery was revealed by an ischemic stroke in a 65-year-old man.
Hydrocephalus developed during the following months. The MRI studies showed that
it could not be explained merely by a permanent compression. However, the patient
improved clearly after a ventriculo-peritoneal derivation. CONCLUSION: The
hydrocephalus could be explained by a "water-hammering" effect due to the
pulsating blood in the ectatic vessel, which created a cerebrospinal fluid
outflow impairment through the third ventricle.
PMID- 9757345
TI - [A free meningioma of the cauda equina].
AB - We report an unusual case of a cauda equina meningioma occurring in a young girl.
This tumor was neurinoma-like. No meningeal attachment was identified in the
neuroradiological study and during its microsurgical removal.
PMID- 9757346
TI - [Chronic subdural hematoma in utero. Case report with literature review].
AB - We present a case of chronic subdural hematoma diagnosed in utero by
ultrasonography, and MRI at 31 weeks gestation. No cause of usual intracranial
hemorrhage was found. There was no trauma. The child was operated after induced
vaginal delivery at 37 weeks gestation, with good results and normal
neuropsychological development after one year. We discuss the symptomatology and
the therapeutic attitude in such cases.
PMID- 9757347
TI - [Isolated intramedullary cysticercosis. Case report].
AB - BACKGROUND AND PURPOSE: Cysticercosis is the most common parasitic disease
affecting the central nervous system. Although it is still very rare in Europe,
the frequency will increase due to the influx of immigrants from the endemic
areas and increasing trips in these countries. Spinal intramedullary
cysticercosis is an uncommon manifestation of neurocysticercosis. CLINICAL
PRESENTATION: We report a case of pure intramedullary cysticercosis in a young
white French girl, presenting as a progressive paraplegia with a cystic lesion in
T4 on MRI. The diagnosis was made only after surgery by pathological examination.
CONCLUSIONS: A preoperative diagnosis of spinal intramedullary cysticercosis must
be suspected not only in an endemic area in the presence of multiple soft tissue
calcifications and segmental lesions revealed by myelography or MRI studies, but
also for all cystic lesion of central nervous system even in no endemic area.
Surgery is the unique treatment which can be used for spinal intramedullary
cysticercosis and with the use of the microsurgical techniques for medullar
surgery the outcome is not as dismal as reported earlier.
PMID- 9757348
TI - [Guidelines concerning severe cranial trauma. French Society of Neurosurgery].
PMID- 9757349
TI - [Suicide of children and adolescents].
AB - The retrospective analysis of the Bonn autopsy material from 1992 to 1996
revealed 11 suicides of children and adolescents, 8 girls and 3 boys. The ages
ranged from 10 to 19 years. The suicides occurred preferentially outdoors in the
warm months of summer, on Monday and in the middle of the week, in the afternoon
and early evening hours. Independent from sex, the children unexceptionally
applied hard suicide methods like hanging or jump from the height. As for the
psychological background, current conflicts within the family or at school on the
background of chronically disturbed family structures were encountered as
prevailing factors.
PMID- 9757350
TI - [Fatal child abuse in Japan and Germany. Comparative retrospective study].
AB - In this study a record for comparative international epidemiological studies on
autopsy cases of child abuse is introduced. The form was proved in a
retrospective comparative survey of cases of fatal child abuse at the Department
of Legal Medicine in Kanazawa (Japan) and Institute of Legal Medicine of Lubeck
(Germany). A total of 33 cases were included. The following data were evaluated:
age and gender of victims and assailants, relationship between victims and
assailants, causes and methods of abuse, chief autopsy findings, and causes of
death. The results were leading into two directions between Kanazawa and Lubeck:
(1) In the years of 1981-1996 in Kanazawa 23 cases of fatal child abuse were
autopsied while during the same period in Lubeck only 10 cases were registered.
(2) While sexual abuse was not registered in Kanazawa, it was recorded twice in
Lubeck.
PMID- 9757351
TI - [Simulated suicide by hanging after homicidal strangulation].
AB - Homicides by hanging and the simulation of suicide by hanging a victim previously
killed or made unable to resist by other means are regarded as extremely rare
events, although especially in German forensic literature cases of this kind were
repeatedly reported. The paper adds another example to the number of observations
published so far: A 23-year-old student strangled his 58-year-old father with an
electric cable until he ceased to show any signs of life. Then he hanged the
victim at the handrail of the staircase with a running noose. From the forensic
point of view the following clues pointed to homicide: presence of massive signs
of facial congestion in spite of the "typical" situation of hanging, horizontal
ligature mark in addition to the noose mark, skin injuries at the head and the
upper extremities, traces of blood near the place where the body was found. The
case history presented emphasizes again that for differential diagnosis the
possibility of a dissimulated homicide has to be considered in all cases where a
body is found suspended.
PMID- 9757352
TI - [A case of suicidal chloroform poisoning].
AB - A 33-year-old man who had suffered from phobia and depressions was found dead in
his kitchen. He was entirely covered by plastic waste disposal bags stuck
together. The corpse was lying flat on his stomach with his face on a towel
soaked with chloroform. Within the plastic cover, on either side of the body's
head, there was located a can half way filled with chloroform. Autopsy revealed
cauterized lips and mucous membranes of the mouth. The morphological findings of
the inner organs were unspecific. For toxicological analyses, air samples from
the pleural cavities of the corpse were taken by way of charcoal tubes and a
microprocessor aided pump. The solvents adsorbed on the charcoal were desorbed
with benzyl alcohol and analyzed by gas chromatography according to standard
procedures. The quantification of the chloroform levels of the body fluids and
the tissue samples of the corpse was performed by extraction with pentane
followed by addition of trichloroethylene as internal standard and consecutive
gas chromatographic analysis. The results of the toxicological analyses confirmed
the diagnosis of a fatal chloroform intoxication.
PMID- 9757353
TI - [Exhumation and no end. A comparative analysis].
AB - If the order to carry out an autopsy has been neglected, exhumation is the only
possibility to obtain findings which allow conclusions on the manner of death,
cause of death and chain of events. The quality of findings will however be
influenced by advanced states of putrifaction. In spite of identical legislature
the number of exhumations carried out at the institutes of legal medicine in
Munchen and Munster differs considerably, as demonstrated by a comparison of the
data from the years 1993-1996. As previously described by other authors, there is
a reciprocal correlation between the number of autopsies and the exhumation rate.
The frequency of autopsies which are ordered can be explained by the varying
application of the statutory framework by the investigation procedure. In some
cases where an exhumation has been carried out, it was difficult to comprehend
why an autopsy was not originally ordered.
PMID- 9757354
TI - [Expert assessment of coital injuries from the forensic medicine viewpoint].
AB - A 38-year-old woman was transmitted to hospital with profuse vaginal bleeding.
The origin of the vaginal injuries (resulting from "normal" sexual intercourse
vs. use of instruments for manipulation in the vagina) was obscure. The wound
pattern is presented and the literature on the subject is reviewed with special
reference to predisposing factors and genesis of coital injuries. Concerning the
wound pattern, reflecting a blunt trauma, a manipulation with a (so far unknown)
instrument, but also with finger or hand could not be proved with the required
certainty. In the presented case the origin of the vaginal injuries from "normal"
sexual intercourse as described by the accused man could not be excluded.
PMID- 9757355
TI - [Suicide by a borderline patient at the end of fatal self-destructive behavior].
AB - The presence of a borderline personality disorder must also be considered in
forensic medicine appraisements, beside the various motivations for a self
injurious behaviour and apart from other psychiatric illnesses. This personality
disorder is frequently characterized by cuts and scratches made by the patients
using sharp objects to inflict themselves when in situations causing great
psychological distress. A case of a young female student is presented who
exhibited a clear auto-destructive behaviour. Due to a tragic psychodynamic
development, she committed suicide by means of carbamazepine intoxikation. In
addition to the impressive morphological and traumatological injury pattern, the
psychiatric case history of the female patient also showed that she had suffered
from a typical borderline personality disorder.
PMID- 9757356
TI - Epidemiology, risk factors, intervention, and prevention of adolescent suicide.
AB - Increasing rates of adolescent suicide are a significant health concern and the
third leading cause of death for this age group. Recent research into
psychiatric, gender-related, family, cultural and neurobiologic risk factors is
reviewed. The effects of suicide exposure and media influences are also examined.
Although many risk factors have been identified, the application of this
knowledge to clinical practice requires further study. The limited number of
studies on prevention and intervention strategies are discussed. High rates of
nonadherence to follow-up remain problematic. More research is needed to develop
appropriate treatments, prevention programs and outcome measures.
PMID- 9757357
TI - Recent patterns of use and associated risks of illicit drug use in adolescents.
AB - Addressing adolescent substance abuse presents a tremendous challenge to the
practicing clinician. Despite ongoing educational and preventive services, and
despite increasing governmental interdiction, substance use by adolescents
continues to be a major national problem. Although present rates of use are lower
than the peak rates in the late 1970s, drug use among adolescents nearly doubled
in the early 1990s and is a significant cause of morbidity and mortality.
Patterns of use continue to evolve. Newer drugs make their way to the streets,
and older drugs are rediscovered. Behavioral and environmental factors increase
the risk for adolescent substance abuse. Identification of use patterns and
familiarity with comorbid behaviors and social risks may help the clinician
identify the adolescent at risk.
PMID- 9757358
TI - Sports-related head injuries.
AB - Head injuries in sports cause serious long-term problems. Appropriate acute and
subacute management of both catastrophic and mild injuries can prevent secondary,
potentially disabling or fatal injury. By understanding the mechanism of injury,
classification, and epidemiology of sports-related head injury, pediatricians can
appropriately care for their athletic patients. The symptoms of a mild head
injury may be transient, but the cumulative effect may have permanent long-term
sequelae. Continued clinical, epidemiologic, and basic science research is needed
to help prevent head injuries and their sequelae in the future.
PMID- 9757359
TI - Adolescents and violent crime.
AB - Violent crime is a key social and public issue that significantly contributes to
the morbidity and mortality of adolescents and places a significant economic
burden on society. Overall, juveniles (legally described as adolescents under 18)
are responsible for only 19% of all violent crime committed in the United States.
However, the peak age incidence for violent offenders is 18, well within the
spectrum of the adolescent age grouping. Over the past 10 years, arrests for
juvenile crime have increased by 67%, leading some experts to worry that, given
the expected increase in the size of the juvenile population by the year 2010,
the number of arrests for juvenile crime will double. Fortunately, there has been
a decline in the rates of juvenile violent crime over the past 2 years. This
article reviews statistical trends, contributing factors and innovative
approaches to prevention and intervention.
PMID- 9757360
TI - Clinical disturbances of attachment in infancy and early childhood.
AB - The development of the attachment behavioral system in infancy has been the focus
of a wide range of research in the past 30 years. The clinical significance of
disturbances in this area of development is currently a major focus for this
research. Research on patterns of attachment in infancy has informed
understanding of the development of psychopathology in later childhood; insecure
disorganized attachment is recognized as an important risk factor in this regard.
The clinical features of reactive attachment disorder in early childhood are also
becoming more clear. Finally, knowledge about the intersection between attachment
and various risk conditions is growing and should inform clinical judgement about
infants and young children requiring intervention. Primary care physicians can
use these findings to identify children in need of intervention.
PMID- 9757361
TI - Childhood eating disorders.
AB - This paper reviews the recent research literature on childhood eating disorders
from a developmental perspective. Although there have been some recent advances
in research, much work remains to be done, especially studies specific to child
and adolescent eating disorders, as well as definitive follow-up studies. Few
data are available on the normal development of eating behavior, or resilience
and risk factors for eating pathology. The best-studied areas include
epidemiological studies, short-term treatment for bulimia nervosa, and outcome in
anorexia nervosa.
PMID- 9757362
TI - Update on acne.
AB - Acne is a common condition seen routinely by both primary care physicians and
dermatologists. Most patients have no underlying pathology and respond to
traditional treatment; others, however, require more individualized evaluation
and aggressive therapy. New information regarding the pathogenesis and treatment
of acne is now available. This update discusses the proper evaluation of early
childhood acne, the emergence of Propionibacterium acnes resistance, and the rare
but serious side effects occasionally seen with minocycline. Advances in the
topical treatment of acne, the use of oral contraceptives in acne, and the use
and efficacy of isotretinoin are also addressed.
PMID- 9757363
TI - Atopic dermatitis.
AB - Atopic dermatitis is the most common skin disease of childhood, and its
prevalence has steadily increased over the last three decades. A chronic,
relapsing condition, atopic dermatitis has a significant impact on affected
children, their families, and the community at large. Although the fundamental
pathogenesis has remained elusive, intensive research has greatly contributed to
our understanding of this disease. As the specific immunobiologic pathways become
deciphered, we have seen the propagation of several new therapeutic options that
rationally attack specific underlying immune system abnormalities. This article
highlights the specific contributions made to the literature over the past year,
with particular attention to the immunopathogenesis of atopic dermatitis, as well
as some new targeted therapies currently and soon to be available.
PMID- 9757364
TI - Anogenital papillomavirus infections in children.
AB - Over the years, our impression of human papillomavirus has changed. Once thought
of as the cause of relatively insignificant skin lesions, its significant role in
malignancy of epithelia and mucosa throughout the body is beginning to be
understood. Also changing, although not as rapidly as we would like is our
understanding of how human papillomavirus infects the body, the concept of
latency, our responses to infection, and how to modify or boost those responses
so as to overcome infection. Research into the specifics of how our immune
systems react, or why they do not, should give us better insight into how and why
treatment therapies work and how to optimize them. Further work into vaccines may
provide the means to eradicate the virus from infected persons, as well as to
prevent the initial infections.
PMID- 9757365
TI - Moles and melanoma.
AB - The melanoma epidemic in adults is well documented, and there is now evidence
that the incidence of malignant melanoma in teenagers is increasing. Risk factors
for melanoma are recognizable in children and include congenital nevi, numerous
common nevi, and atypical nevi. Large congenital nevi overlying the head or spine
also carry risk for central nervous system involvement, which, if symptomatic,
carries a grave prognosis. Laser therapy has recently been advocated for small
congenital nevi but often yields only temporary improvement. Adjuvant therapy
with interferon alfa-2b holds promise for patients with metastatic melanoma.
Melanoma risk is also linked to sun sensitivity and childhood exposures, and
sunscreen use has been promoted for prevention of skin cancer. Because many
sunscreens offer protection from ultraviolet (UV) B but not UVA, spectra that may
be involved in melanoma induction, pediatricians should counsel their families to
practice a full program of sun protection that includes sun avoidance and
protective clothing and eyeware in addition to sunscreens.
PMID- 9757366
TI - Laser therapy and dermatologic surgery.
AB - Numerous advances in surgery and laser therapy applicable to pediatric
dermatologic practice have been made. The use of EMLA (eutectic mixture of local
anesthetics; Astra USA, Westborough, MA) cream (lidocaine and prilocaine) is
invaluable for office dermatologic procedures in children. Despite high patient
tolerance, rare adverse events have been described. Newer topical anesthetics
with faster onset and greater efficacy are discussed, with special emphasis on
their application to the pediatric dermatology patient. Appropriately
administered, these newer agents may make certain procedures in children painless
or minimally uncomfortable. Newer, improved tissue adhesives are under
development and may replace and surpass traditional surface suturing. Limitations
to the use of the pulsed dye laser for vascular lesions in children are
discussed.
PMID- 9757367
TI - Endocrine and metabolism.
PMID- 9757368
TI - Growth hormone therapy for non-growth hormone-deficient children with short
stature.
AB - A summary of the majority of the available uncontrolled studies of 322 children
with idiopathic short stature treated with growth hormone showed that the final
height attainment over predicted adult height was only +2.85 cm (+0.49 SD score).
Furthermore, a summary of seven studies reported that the spontaneous outcome in
children with untreated idiopathic short stature was more than +1 SD score in
final height compared to height at presentation; patients with delayed puberty
spontaneously gained more than +2 SD score as adults. Recent reevaluations have
concluded that short stature is not associated with clinically significant
psychologic morbidity, and the psychologic outcome in response to growth hormone
treatment of the short normal child showed no discernable difference in
psychologic benefit, despite a difference in height gained. A recent editorial
has strongly advised against the expanded use of growth hormone in the normal
short child.
PMID- 9757369
TI - Newer aspects of the pathophysiology, evaluation, and management of obesity in
childhood.
AB - Childhood obesity is a silent epidemic in America. Although most practicing
pediatricians recognize clinically significant obesity and are aware of its
potential morbidities, they often lack the tools to accurately quantify it, are
rarely able to successfully treat it, and usually have no consistent approach to
its prevention. In this update, recent information concerning the measurement,
prevalence, natural history, complications, causes, evaluation, and management of
childhood obesity is discussed.
PMID- 9757370
TI - Aquaporin molecular biology and clinical abnormalities of the water transport
channels.
AB - In the past year, significant progress has been achieved in the research on
aquaporins (AQPs), a family of structurally related molecular water channels.
Three novel AQPs were identified, giving a total of ten mammalian AQPs. An
important step forward in identifying the aqueous pore in AQP molecules was the
determination of the three-dimensional structure of AQP1. The expression pattern
of individual AQPs in different tissues was determined in more detail and AQP
knockout mice have been generated. The discovery of a severe urinary
concentrating defect in AQP1-knockout mice was remarkable. Only AQP2, the
vasopressin-sensitive water channel in the kidney, which is mutated in autosomal
recessive and dominant cases of nephrogenic diabetes insipidus, has been shown to
be involved in human disease. The finding of changed AQP2 expression in several
acquired water balance disorders may pave the way toward developing treatments
for these clinical problems.
PMID- 9757371
TI - Molecular biology and clinical importance of the Ca(2+)-sensing receptor.
AB - The Ca(2+)-sensing receptor (CaR) is a member of the seven-transmembrane domain,
G protein-coupled receptor super-family. In the parathyroid gland, it mediates
the inhibitory effects of extracellular Ca2+ on the secretion of parathyroid
hormone. In the kidney, activation of the CaR causes decreased reabsorption of
Ca2+ from the tubular lumen. Mutations in the CaR gene produce abnormalities of
Ca2+ homeostasis. Heterozygous loss-of-function mutations cause familial
hypocalciuric hypercalcemia. Homozygous loss-of-function mutations cause neonatal
severe hyperparathyroidism. In contrast, gain-of-function CaR mutations result in
autosomal dominant and sporadic hypoparathyroidism. The resulting
hypoparathyroidism and hypocalcemia can range from asymptomatic to life
threatening. Patients with hypocalcemia due to CaR mutations also show
disproportionate hypercalciuria that may increase the risk of nephrocalcinosis,
nephrolithiasis, and renal insufficiency.
PMID- 9757372
TI - Clinical utility of markers of bone turnover in children and adolescents.
AB - We review the past years' literature on biochemical markers of bone turnover. A
general introduction to markers of bone formation and bone resorption is followed
by reference values of bone turnover in neonates, infants, and prepubertal and
pubertal children. We describe intervention with calcium and physical activity in
healthy children and bone turnover in patients. The predictive value of a single
measurement of bone markers in individuals is poor, due to the large biologic
intraperson variation for bone markers in general. Serious osteoporosis can be
diagnosed by the combined results of measurement of several bone formation and
resorption markers.
PMID- 9757373
TI - Diabetes insipidus as a hallmark neuroendocrine complication of neonatal
meningitis.
PMID- 9757374
TI - Neonatal jaundice, animal-based injuries, and immunizations.
AB - This review presents in a clinically relevant context the past year's
investigations in three areas of pediatrics that commonly face the office-based
pediatric provider. Although transcutaneous quantification of jaundice may help
discern which patients warrant further evaluation, thereby saving patients pain
and expense, this technology has not yet significantly changed clinical
management of the hyperbilirubinemic infant. A brief overview of animal bites
demonstrates that although most are innocuous, proper treatment of these
potentially serious injuries is critical in preventing further complications. The
number of immunizations given in the first 2 years of life has increased, and
although new combination vaccines may eventually simplify the schedule,
persistent vigilance is more important than ever to avoid delays in vaccine
administration.
PMID- 9757375
TI - [Ebstein's anomaly: when should a patient have operative treatment?].
AB - Ebstein's anomaly is a complex malformation of the tricuspid valve where the
hinges of the septal and/or posterior leaflets are displaced downward into the
right ventricle. The leaflets show variable deformations. In general, the
anterior leaflet is enlarged. For those patients who have only mild symptoms,
medical management is recommended, but operative treatment is indicated if
progressive deterioration is evident. The timing of the surgical intervention is
still a matter of controversy, especially since the results of surgical treatment
were substantially improved by further development of repair techniques. Between
1974 and August, 1997, 69 patients with Ebstein's anomaly underwent surgical
repair. In 65 patients (94.2%) tricuspid valvuloplasty was feasible, mainly by
creating a monocusp valve with the "single-stitch technique", developed in our
clinic by F. Sebening. Four patients required primary valve replacement with a
bioprosthesis. Ten reoperations (14.5%) were necessary: 6 repeat valvuloplasties,
4 valve replacements. There were 2 hospital deaths (2.9%), the late mortality was
8.7% (6 patients). Since 1992, our valvuloplasties have been evaluated by
intraoperative transesophageal echocardiography (TEE). Follow-up was obtained in
58 patients (95%) over a period of 4 months to 21.0 years (median 5.3 years, mean
7.6 years). The actuarial survival rate (Kaplan-Meier) was 96.5% +/- 2.4% at 1
year and 83.3% +/- 5.6% at 21 years. Pre-operatively, the majority of patients
were in New York Heart Association functional Class III. At follow-up evaluation,
nearly all patients showed substantial improvement of their pre-operative status,
94.8% were in NYHA Class I or II. Doppler echocardiographic studies demonstrated
good tricuspid valve function in most patients. The valvuloplasty developed in
our hospital using a single-stitch technique is a rewarding operation, which
yields good long-term results. An analysis of the postoperative deaths revealed
that all patients but one suffered from endstage cardiac disease and had a cardio
thoracic ratio greater than 0.65. This supports the importance of surgical
intervention in time. In our opinion, operation is even indicated for those
patients in functional Class II who reveal clinical deterioration.
PMID- 9757376
TI - [Pseudoaneurysm in the vicinity of the ascending aorta caused by contained
disruption at the insertion site of a coronary artery bypass graft. A case
report].
AB - In this case report a 65-year-old patient came into the emergency ward with acute
chest pain after coronary artery bypass graft operation in 1985. On routine chest
X-ray in 1995 a mediastinal widening was diagnosed. The chest X-ray in 1997
(Figure 1) showed an increase of the diameter of the known mediastinal widening.
Therefore a CT-scan was performed (Figures 2a and 2b). This showed an enhancement
of contrast material in a contained structure, without identifying its origin.
Therefore a coronary angiography was done. Here, we diagnosed a contained
disruption of the aorta at the insertion site of the bypass graft at the right
coronary artery. Figure 3a shows leakage of contrast material out of the aorta
into the pseudoaneurysm and in Figure 3b this is demonstrated in a schematic
drawing. Figure 4a shows supraselective imaging of the pseudoaneurysm,
demonstrated in a schematic drawing in Figure 4b. As the chest pain could only be
handled by i.v.-medication, betablocker and bed rest we decided to operate. Intra
operatively the diagnosis was confirmed (Figure 5a and 5b). Postoperatively the
patient died due to cerebral ischemia. Despite the lethal outcome an operative
revision appears even retrospectively justified because of the increasing size of
the pseudoaneurysm in addition to new symptoms that were difficult to treat. On
the other hand there are no data available in order to estimate the risk of a
spontaneous course.
PMID- 9757377
TI - [Angina pectoris in leiomyoma].
AB - A 72-year-old patient presented himself with typical symptoms of coronary heart
disease and was scheduled for invasive diagnostic procedures. Cardiac risk
factors were smoking and arterial hypertension. The physical examination was
inconspicious. In the laborchemistry a hemoglobin of 79 g/l with a mean
corpuscular volume of 63 fl and a mean corpuscular hemoglobin of 20 pg was
conspicuous. The serum iron was with 42 micrograms/dl in the lower norm.
Transferrin, bili-rubin and lactate dehydrogenase were normal. Then in the
gastrointestinal investigations he was diagnosed with a leiomyoma of the
intestine that led to chronic anaemia and additionally to chest pain
characteristic for angina pectoris. After the removal of the tumor and
normalization of hemoglobin this patient was free from symptoms of the disease.
The coronary angiography revealed a complex stenosis of the right coronary artery
with collaterales and not significant stenosis both of the left coronary
arteries. In patients with angina pectoris anaemia as the possible and only cause
of angina ought to be verified. It is therefore necessary after normalization of
hemoglobin and clarification of the cause for the anaemia to apply a test for
coronary ischemia.
PMID- 9757378
TI - Chest pain in cardiac syndrome X--caused by neuromuscular disorders?
AB - We wanted to find out if chest pain in cardiac syndrome X can be a manifestation
of neuromuscular disorders. Five patients with cardiac syndrome X (3 women, 2
men), aged 34 to 70 years, consented with a clinical neurological examination,
muscle enzyme testing, electroneurography of the right median and peroneal nerves
and electromyography of the right brachial biceps and anterior tibial muscles. A
neuromuscular disorder was found in 1 of the 5 investigated patients. The 60-year
old man presented with a monoparesis of the left leg and sensory dysfunction of
the left upper and lower limb. He was diagnosed as having either posttraumatic
myelopathy or radiculopathy. Since chest pain in cardiac syndrome X can be caused
by neuromuscular disorders, a comprehensive neurological examination is
recommended in patients with this disorder.
PMID- 9757379
TI - [Pleural and pericardial effusion after pacemaker implantation as first
manifestation of malignant tumors].
AB - We report 2 cases with unusual "complications" after pacemaker implantation. One
patient developed hemorrhagic pleural and 1 patient pericardial effusion. Both
manifestations of hemorrhage were felt to be due to complications in relation to
the pacemaker implantation. However, in both patients cytologic analysis of the
effusion revealed malignant cells, in 1 case from an ovarian cell carcinoma, in
the other case from an adenocarcinoma of unknown origin. Our report indicates,
that under rare circumstances pleural or pericardial effusion after pacemaker
implantation may be the first manifestation of a malignant process independent of
the pacemaker implantation procedure.
PMID- 9757382
TI - [Sodium and water balance for clinical routine practice].
PMID- 9757381
TI - [Pharmacoeconomic evaluation of pravastatin in the secondary prevention of
coronary heart disease in patients with average cholesterol levels. An analysis
for Germany based on the CARE study].
AB - Those people who are to decide about health care systems are increasingly forced
to identify unnecessary costs and achieve savings in health care. Especially for
diseases with high prevalence like illnesses of the heart and the circulatory
system preventive measures are very important. This economic analysis tries to
clarify whether the secondary-preventive application of the HMG-CoA reductase
inhibitor pravastatin is, apart from the clinical benefit, economically justified
in patients suffering from coronary heart disease with average cholesterol
levels. In the case of this study, the underlying type of economic evaluation was
an incremental cost-effectiveness analysis. The outcome was defined as costs per
life-year saved. This retrospective study is based on the results of the CARE
(Cholesterol And Recurrent Events) study which has been published elsewhere [21].
When calculating costs we took into account the perspective of 3rd party payers
(public health insurance) in Germany. The calculation of cost-effectiveness was
carried out for the whole study population in CARE as well as for all patients
aged 60 or more years in the CARE study. This was done because the different
groups vary by the numbers of avoided myocardial infarctions, strokes and loss of
life years. Netcosts for pravastatin therapy, i.e. drug costs for pravastatin
minus costs for avoided events, were about 9.54 Mio DM (referring to 1,000
patients treated for a period of 5 years). Net-costs for patients aged 60 or more
years were 8.18 Mio DM. The effectiveness was defined as the number of life years
saved and amounted to 216 years of life saved (YOLS) in the overall study group.
For patients aged 60 or more years we found that 358 years were saved. The costs
per life years saved (i.e. the net-costs of pravastatin therapy divided through
the number of life years saved) turned out to be 44,000 DM per person in the
study group. For patients over 60 the costs were 23,000 DM. Lipid-lowering with
pravastatin in the secondary prevention of coronary heart disease in Germany is
cost-effective. In those patients aged 60 or more yeas the use of pravastatin is
even more cost-effective than in all patients included in the CARE study.
PMID- 9757380
TI - [Perforation and rupture of coronary arteries].
AB - Spontaneous rupture of coronary arteries as well as coronary perforation during
percutaneous interventions are rare but potentially life-threatening incidents
often resulting in emergency surgery. Frequency of acute perforation due to
therapeutic catheterization varies according to the devices employed. With
conventional balloon angioplasty it is estimated to be 0.1 to 0.2% whereas
substantially higher rates of up to 3% have been reported with the use of so
called "new devices" (i.e. directional atherectomy, rotablation, excimer laser
angioplasty or extractional atherectomy). Interventional strategies for
nonsurgical treatment of acute coronary perforations during catheterization
procedures have been developed. In recent times, availability of coronary stent
grafts allows for a percutaneous resolution of acute perforations while
maintaining vessel patency. Whereas iatrogenic perforations in the
catheterization laboratory may thus be treated immediately at the site of their
occurrence, rupture of pre-existing but potentially unknown coronary pathology
frequently is associated with a diagnostic interval, giving rise to serious
clinical events (i.e. myocardial infarction, cardiac tamponade, malign
arrhythmias or sudden death). It may be warranted to advocate prophylactic
treatment of rupture-prone coronary conditions even on incidental diagnosis. This
can either be performed by cardiothoracic surgery or, in suitable cases, by
interventional therapy. Implantation of coronary stent-grafts could prove to
become the therapy of choice due to its technical facility, safety and the short
length of hospital stay associated with it. Before general recommendations can be
made, however, as to the extension of indication for these novel coronary
devices, further clinical studies encompassing long-term clinical and
angiographic follow-up are needed.
PMID- 9757383
TI - [Disorders of potassium balance].
PMID- 9757384
TI - [Disorders of magnesium balance].
PMID- 9757385
TI - [Disorders of acid-base balance].
PMID- 9757386
TI - [Disorders of calcium and phosphate homeostasis].
PMID- 9757387
TI - [Disorders of trace element homeostasis].
PMID- 9757388
TI - [Chronic diarrhea].
PMID- 9757389
TI - [64-year-old patient with recurrent left orbital pseudotumor].
PMID- 9757390
TI - [61-year-old patient with bronchiectasis, vitiligo and chronic atrophic
gastritis].
PMID- 9757391
TI - [HMG-CoA reductase inhibitors].
PMID- 9757392
TI - [Detection of allergy to amalgam or other dental alloys].
PMID- 9757393
TI - [Health risk caused by sugar substitutes].
PMID- 9757394
TI - [Thrombocyte aggregation inhibition].
PMID- 9757395
TI - [Drug interactions. Proton pump inhibitors. 1].
PMID- 9757396
TI - [Measuring serum lipoproteins].
PMID- 9757397
TI - [Liver transplantation in familial amyloid polyneuropathy].
PMID- 9757398
TI - [Mycophenolate mofetil in comparison with other immunosuppressive drugs].
PMID- 9757399
TI - [Comment on the contribution: Nikol S. et al. 51-year-old patient with reversible
infarct-like ECG changes].
PMID- 9757400
TI - Overview of special issue on adolescent suicide: risk, assessment, and treatment.
AB - Regarding the pressing international health problem of adolescent suicide, the
contributors to this special issue have provided new findings and perspectives
around the theme of risk and its assessment. These contributions are summarized,
and are viewed as examples of the reciprocal efforts of scientists and clinicians
to systematize and deepen knowledge on adolescent suicide, and thus beneficially
affect a pernicious health problem.
PMID- 9757401
TI - A process model for assessing adolescent risk for suicide.
AB - As the incidence of adolescent suicide within our society continues to rise, it
becomes increasingly important for the mental health professional to be able to
accurately assess suicide risk in adolescents who seek help. This process model
discusses primary risk factors (previous attempt, affective disorders, and
hopelessness), secondary risk factors (substance abuse and personality or
behavioral disorders), situational risk factors (family functioning, suicide
exposure, social support, life stressors, and homosexuality), and their combined
implications and significance in determining an adolescent's level or risk for
suicide. Use of both empirical data and clinical intuition are integrated to form
a working client model that is continuously reassessed in four stages, guiding
the mental health professional through a comprehensive assessment process.
PMID- 9757403
TI - Suicidal ideation in an adolescent clinical sample: attachment patterns and
clinical implications.
AB - This study investigated the relationship between attachment patterns and suicidal
ideation in a clinical sample of adolescents. Participants (n = 116) were
assessed on level of current ideation through self-report questionnaires.
Lethality of methods contemplated was also rated on a subset of the sample (n =
16) who, in addition to endorsing current suicidal ideation, presented a plan on
a diagnostic interview. Quality of attachment to care-givers based on a semi
structured clinical interview was assessed using Bartholomew's two-dimensional,
four-category model of attachment. Categorical analyses indicated that youth with
predominantly fearful or preoccupied attachment were more likely to endorse
suicidal ideation than were predominantly secure or dismissing youth. Severity of
suicidal ideation was positively correlated with ratings of fearfulness and
negatively correlated with ratings on the secure and dismissing patterns. Greater
lethality in methods of contemplated suicide was positively correlated with
preoccupied tendencies. The importance of attachment theory for understanding the
factors underlying suicidal ideation in troubled youth is discussed and
implications for therapeutic intervention are presented.
PMID- 9757402
TI - Gender differences in rates and correlates of suicidal behaviour amongst child
psychiatric outpatients.
AB - Childhood suicide is an increasing problem in Western society. Identification of
those at risk of suicidal behaviour is of priority to identify children with
consequent mental suffering, and prevent successful attempts. The study
determined factors associated with suicidal ideas, attempts or threats in 5426
psychiatric outpatients aged between 8 and 17 years who attended a British
teaching hospital. Multivariate logistic regression analyses were performed by
sex on the data from the standard department questionnaire. Substance abuse,
depression and disturbed relationships with adults were predictors of suicidal
behaviour for both sexes. For female subjects, antisocial behaviour was also
associated. In girls alone, depression had significant interaction effects with
substance abuse and conduct disorder. Possible reasons for these differences are
discussed.
PMID- 9757404
TI - Reasons for living in a clinical sample of adolescents.
AB - The psychometric properties and validity of the Reasons for Living (RFL)
Inventory were examined in a sample of psychiatrically hospitalized adolescents
(n = 253), aged 13 to 18 years, identified as suicide ideators, suicide
attempters, and psychiatric controls. Confirmatory factor analysis suggested that
the original RFL factors did not provide a good fit; exploratory factor analysis
identified five factors, of which three were identical with the original RFL
factors. Factor scores differentiated suicidal from non-suicidal adolescents and
attempters from ideators. Correlational analyses indicated that RFL factors were
associated with suicidal ideation, depression, and hopelessness, and predicted
unique variance in suicidal ideation over that accounted for by depression and
hopelessness. Our findings provide support for the RFL as a sound measure for
clinical and research assessment in adolescents.
PMID- 9757405
TI - The relationship between lethality of attempted suicide and prior suicidal
communications in a sample of residential youth.
AB - Some type of suicidal communication precedes 80% of attempted and completed
suicides in adolescents. This study investigates the relationship between the
number of suicidal communications prior to an attempt and the lethality of the
attempt in a sample of adolescent youth residing in a residential treatment
facility. The sample consisted of 46 youth who had a suicide attempt while in a
large group home residential facility over a 9-year period. Results indicated
that attempters who made fewer suicidal communications beforehand tended to use
more lethal methods in their attempts. Attempters with two or more preceding
suicidal communications had significantly lower lethality in their attempts than
did those with fewer suicidal communications. Few differences emerged between the
groups in regards to demographic or psychosocial variables.
PMID- 9757406
TI - Negative life events and adolescent suicidal behavior: a critical analysis from
the stress process perspective.
AB - In the present review we examine empirical evidence concerning relationships
between negative life events and adolescent suicidal behavior. Separate critical
analyses were made for suicidal ideation, suicide attempts and completed suicide,
suggesting common and differential aspects. Although there is evidence supporting
the hypothesis that life events may comprise a risk factor for adolescent
suicidal behavior, their contribution tends to be moderate or weak. A problem
with past research is that it has not adequately incorporated mediating and
moderating variables into pathways that link psychosocial stressors and suicidal
outcomes. A stress process model is presented as a possible alternative to better
understanding the relationships between stress and suicide, and to provide a
conceptual and heuristic framework for future research.
PMID- 9757407
TI - Suicidal ideation and acts of self-harm among Dublin school children.
AB - The purpose of this study is to ascertain rates of suicidal ideation and self
harm in a classroom population of 13- and 14-year-old children using a screening
questionnaire and to confirm accuracy of these screening results by home
interview. There were significant differences between suicidal ideation rates at
screening and at home interview (44% vs. 29%) and between self-harm rates (8% vs.
2%). Those with suicidal ideation at home interview believed more in a "right to
suicide" and believed suicidal ideation to be more widespread among adolescents.
School factors were believed by respondents to be important in the causation of
adolescent suicide. Fewer than one-fifth would advise consultation with a
psychiatrist to a suicidal friend.
PMID- 9757409
TI - Family predictors of suicidal symptoms in young adolescents.
AB - A 1-year longitudinal study tested the model that the relation between maternal
depression and adolescent suicidal symptoms is mediated by family functioning.
Participants were 240 children (mean age = 11.86 years) and their mothers; 77% of
the mothers had a history of a mood disorder and the remaining 23% were lifetime
free of psychopathology. An adolescent suicide index was created based on suicide
items from the child and parent versions of the Children's Depression Inventory,
Child Behavior Checklist and Children's Depression Rating Scale, administered at
both Time 1 and 2. Family functioning was assessed with the Family Relationship
Index completed by mothers and children at Time 1. Results indicated that the
relation between maternal depression and adolescent suicide symptoms at Time 2
was mediated by perceived family functioning, controlling for suicide symptoms at
Time 1.
PMID- 9757408
TI - Screening for suicidal ideation in children and adolescents: methodological
considerations.
AB - The prevalence of suicidal ideation and attempts varies considerably depending on
(a) who the reporters are for youth suicidality, (b) the degree of retrospection
required, and (c) the type of measure used to assess suicidality. The purpose of
this study is to examine some of the methodological issues that should be
considered when administering suicidal screening measures to children and
adolescents. The risk group was comprised of offspring of depressed mothers (26
mothers with Bipolar Disorder, 42 mothers with Major Depressive Disorder). The
comparison group was comprised of offspring of mothers without past or current
psychiatric diagnosis (30 mothers). Two siblings from each family were recruited
for participation (n = 192). Screening for youth suicidality was based on (a)
structured diagnostic interviews with youth (yielding interval and lifetime
reports), (b) youth self-reports, and (c) maternal reports. Assessments were made
when the younger siblings were approximately 6, 9, and 14 years of age and older
siblings were approximately 6, 9, 13, and 18 years of age. Mothers reported a
lower prevalence of youth suicidal content than did youth. Discrepancies between
mother and child report were more common in the risk group. When lifetime
retrospection of suicidal content was assessed, fewer youth reported suicidal
thoughts or actions than when suicidal content was assessed approximately every 3
years. Also, the prevalence of self-reported suicidal content was somewhat higher
(7 to 13%) than when assessing suicidality within the context of an interview.
Child and maternal characteristics were found to correspond to patterns of
consistent and discrepant reporting.
PMID- 9757410
TI - Family rigidity, adolescent problem-solving deficits, and suicidal ideation: a
mediational model.
AB - Family rigidity and adolescent problem-solving deficits have each been linked to
adolescent suicidal behaviors. The objective of the present study was to evaluate
the hypothesis that family rigidity has primarily an indirect effect on
adolescent suicidal ideation through its effect on adolescent problem-solving
deficits. College students and their parents completed the Family Adaptability
and Cohesion Evaluation Scale II. Students also completed the Problem-Solving
Inventory and the Adult Suicidal ideation Questionnaire. Structural equation
models confirmed that family rigidity has an indirect effect on adolescent
suicidal ideation through its effect on adolescent problem-solving deficits.
Directions for treatment efforts are discussed.
PMID- 9757411
TI - Suicidality and cognitive vulnerability to depression among college students: a
prospective study.
AB - Using a behavioral high-risk two-site prospective design, we tested the cognitive
vulnerability hypotheses about suicidality. Consistent with prediction, the high
cognitive risk (HR) participants were more likely than the low cognitive risk
(LR) participants to exhibit suicidality, measured by both structured diagnostic
interview and questionnaire self-report, during the 2 1/2 year prospective follow
up period. Moreover, when the prospective period was examined as a whole, the
mediation hypothesis derived from the cognitive theories was strongly supported.
Hopelessness appeared to mediate the obtained relationship between cognitive
vulnerability and suicidality. Finally, the obtained relationship between
cognitive vulnerability and suicidality was not mediated by other hypothesized
risk factors for suicidality not specified in the cognitive theories, such as
past suicidality, personal history of depressive disorders, borderline and
antisocial personality dysfunction, and parental history of depression.
PMID- 9757412
TI - An integrative conceptual framework for assessing and treating suicidal behavior
in adolescents.
AB - Suicidal adolescents represent a uniquely demanding clinical population.
Regardless of psychotherapeutic orientation, the existing standards of care
demand a relatively broad and integrative approach with multiple and specific
treatment targets, as well as ongoing and repeated risk assessment. The current
article provides an integrative conceptual framework for these tasks in day to
day clinical practice with essentially two goals: (1) to provide a summary of
therapeutic and assessment tasks (i.e. the content of therapy and assessment)
consistent with existing standards of care and supported by empirical findings,
and (2) to emphasize the varied roles, tasks, demands and limitations of
psychotherapy with suicidal adolescents.
PMID- 9757413
TI - Adolescent suicide risk today: a paradox.
AB - A review of international statistics indicates that youth suicide rates are not
increasing in all nations. Furthermore, it is suggested that the quality of life
in nations is improving and that this improvement itself may increase the risk of
suicide, especially in youth with narcissistic personality traits and antisocial
personality disorder traits.
PMID- 9757415
TI - [Non-epileptic paroxysmal movement disorders].
AB - Non-epileptic paroxysmal dyskinesias present with different forms of
extrapyramidal hyperkinesias (dystonia, chorea, athetosis, ballism) in variable
combinations and with cerebellar signs, respectively. They may be classified as:
1. paroxysmal dystonias/choreoathetoses (paroxysmal dystonic choreoathetosis =
PDC), paroxysmal kinesigenic choreoathetosis = PKC, intermediate form) and 2.
paroxysmal ataxias (PA) (PA with myokymia and neuromyotonia, azetazolamide
responsive PA). Nocturnal paroxysmal dystonia is now regarded as one form of
nocturnal frontal lobe epilepsy. Research in molecular genetics has substantially
contributed to the etiologic understanding of paroxysmal dyskinesias: In
different families linkage has been successfully completed for PDC (chromosome
2q) and PA (chromosomes 12p, 19p). PA are now identified as channelopathies with
mutations in the potassium channel (PA with myokymia and neuromyotonia) and the
calcium channel gene (azetazolamide-responsive PA).
PMID- 9757414
TI - [S100B: pathogenetic and pathophysiologic significance in neurology].
AB - S100B is a multifunctional member of the S100-calmodulin-troponin superfamily of
proteins and can modulate the activity of other intracellular proteins following
binding of calcium. S100B has been shown to exhibit regulatory effects on cell
growth and differentiation as well as on cell shape and energy metabolism. S100B
has neurotrophic properties and stimulates glial cell proliferation in vitro and
in vivo. Overexpression of S100B has been proposed as a pathogenetic factor in
plaque formation in patients with Alzheimeris disease and Down syndrome.
Furthermore, S100B-specific T-lymphocytes have been shown to be encephalitogenic
in the animal model of experimental autoimmune panencephalitis (EAP).
Phenotypically and functionally similar S100B-specific T-cells can also be
recovered from the peripheral blood of humans making S100B a potential candidate
autoantigen in multiple sclerosis. Here the basic biochemical, molecular and
functional properties of S100B are reviewed with special regard to the potential
pathogenetic role of S100B in Alzheimeris disease, Down syndrome and multiple
sclerosis.
PMID- 9757416
TI - [X-chromosomal recessive spinobulbar muscular atrophy (Kennedy type). Description
of a family, clinical aspects, molecular genetics, differential diagnosis and
therapy].
AB - The Kennedy-Syndrome is a X-linked recessive bulbospinal muscular atrophy, in
some cases associated with endocrinological disturbances such as androgen
resistance and diabetes mellitus. The age of onset is usually between 20 and 40.
Presenting symptoms are proximal flaccid weakness, fasciculations, cramps or
tremor. Disease progression is usually slow and live expectancy is normal. It is
important to distinguish the Kennedy-Syndrome from amyotrophic lateral sclerosis,
spinal muscular atrophy, muscular dystrophies and other types of motor neuron
disease. Kennedy disease is caused by an expanded trinucleotide repeat in the
androgen receptor gene. Genetic analysis allows a precise-diagnosis on an
individual basis and reliable genetic counselling. An effective medical treatment
does not yet exist.
PMID- 9757417
TI - [Influence of the Esmarch splint on chewing and tongue muscle activity during
sleep].
AB - To clarify the functional mechanism of the Esmarch device in the treatment of
sleep apnea, its effect on muscle activity during sleep was studied
electromyographically with and without the appliance at the inferior head of the
lateral pterygoid muscle, the genioglossal muscle, and the masseter muscle in 15
patients with sleep apnea syndrome. During the obstructive apnea the muscles
showed significantly lower amplitudes than before the apnea. No significant
decrease in the amplitude was observed during the central apnea, but, after the
obstructive and central apnea, significantly higher amplitudes were seen than
beforehand. The amplitudes rose after the placement of the appliance, and the
amplitudes of the genioglossal and lateral pterygoid muscles during obstructive
apnea increased significantly after the insertion of the appliance. The results
suggest that the device can activate the masticatory and tongue muscle activity
and indicate that the muscles activated with the appliance can prevent
obstruction in the oropharynx. The Esmarch device not only helps avoid
obstruction by mandibular protraction, but also affects function by activating
the muscles.
PMID- 9757418
TI - [Clinical application of transcranial color-coded duplex ultrasound for detection
of intracranial aneurysms].
AB - We investigated 88 Patients with a total of 102 angiographically diagnosed
intracranial aneurysms by means of transcranial colour coded Duplex sonography
(TCCD) during a time period of 15 months. Both the size and the localization of
the aneurysms were determined. Seventy aneurysms (77%) with a diameter of 16 +/-
8 mm (6-55 mm) were detectable, with excellent visualization in 36 (42%),
moderate visualization in 34 (40%), and no sufficient visualization in 16 (16%)
aneurysms, respectively. In another 16 cases (16%) there was no sufficient vone
window. Thrombotic material inside the aneurysm was detectable in 16/20 cases
(75%), visualization of coil embolized aneurysms in 12/25 patients (48%). TCCD
allows the follow up of cerebral aneurysms, with the detection of thrombosis and
treatment effects after embolization. The method is not valid for the detection
of intracranial aneurysms.
PMID- 9757419
TI - [Systemic thrombolysis with plasminogen activator in chronic stroke patients].
AB - Following the study protocol, we stratified the 615 patients of ECASS I according
age (< or =/-70 years) and analysed the response to intravenous rt-PA in both
subgroups. The older patients (248) suffered from the same stroke severity as the
younger patients (367) experienced, however, a more severy clinical course
(placebo group after 3 months after stroke: Barthel Index 50 vs. 85, mortality
24% vs. 11%). Treatment with rt-PA increased the proportion of undisabled
patients at 3 months after stroke onset significantly only in the younger
patients. The risk for brain parenchymal hemorrhage was increased by the factor
of 4.7 and 4.6 in both age groups. It is obviously harder to achieve an
undisabled state by systemic thrombolysis in the elderly. Facing the risk of
brain hemorrhage associated with rt-PA, the risk-benefit-ratio may be less
favourable in patients over 70 years.
PMID- 9757420
TI - [Diffusion-weighted imaging in acute stroke].
AB - Magnetic resonance imaging represents today the most important tool in
neuroradiology for both clinical practice and research. MRI allows imaging of the
human body in 2 or 3 dimensions with variable tissue contrast. The natural
diffusion of tissue protons can now be used as a supplementary contrast
mechanism. Different MRI techniques can be used to obtain clinically useful
diffusion-weighted images. These techniques all require the use of strong
gradient pulses in order to obtain the diffusion contrast. In the current
article, the most important physical principles of diffusion measurement are
presented. After a short introduction into the basic physical principles, we will
present the prerequisites and limitations of clinically relevant applications
today. Finally a few select examples of clinical use of these techniques in the
acute diagnosis of stroke will be presented.
PMID- 9757421
TI - [Value of antibody titers for diagnosis of neuroborreliosis].
AB - Neuroborreliosis is a very frequent subtype of infection with Borrelia
burgdorferi. Because of the widely spread inapparent infections finding of
diagnosis by analysis of serum antibodies is very difficult. In the years 1990
1994 the serum of 6.775 patients of the Department of Neurology in Homburg,
Germany was analysed with regard to Borrelia burgdorferi specific IgG antibodies.
24% showed a positive serum titer and 20% a borderline result. 73 patients showed
a specific intrathecal IgG antibody synthesis. In contrast to patients with
antibodies in serum these patients showed a significant cumulation during summer.
The high percentage of positive serum titers and the season independence support
the assumption of widely spread inapparent infections. If a patient shows
neurological symptoms the finding of serum antibodies against Borrelia
burgdorferi is not sufficient for the diagnosis of Neuroborreliosis. A specific
intrathecal synthesis of antibodies, is the most reliable serological indicator
for Neuroborreliosis. Intrathecal synthesis usually starts three to four weeks
after the first clinical symptoms.
PMID- 9757422
TI - [Schizophreniform psychosis with polydipsia and electrolyte imbalance in multiple
sclerosis].
AB - We present the case report of a young woman who suffered from schizophrenia-like
psychosis leading to polydipsia and consequent water intoxication. Because of
progressive somnolence and epileptic seizures therapy on the intensive care unit
became necessary. Findings of MRI and cerebrospinal fluid were consistent with
the diagnosis of chronic inflammatory disease of the central nervous system. As
other possible causes could be excluded, multiple sclerosis seemed to be most
probable. Simultaneous incidence of schizophrenia and multiple sclerosis and the
differential diagnosis of central pontine myelinolysis following hyponatremia are
discussed.
PMID- 9757423
TI - [A rare cause of peracute vision loss: pseudotumor cerebri. Case report of course
with recurrence after decompression of the optic nerve].
AB - In primary pseudotumor cerebri (PTC) intracranial pressure is elevated by so far
unknown mechanisms. There is a wide range of clinical courses. Therapy is
controversial. We present a case of PTC with acute visual loss. After optic nerve
sheath decompression a relapse occurred. A 30-year old female patient experienced
visual loss within 48 h accompanied by headache and slight neck stiffness. Visual
acuity was 1/50 in the right eye; in the left eye just hand movements and light
were perceived. Fundoscopy revealed a 9 dptr. prominent optic disc bilaterally.
After optic nerve sheath decompression (ONSD) she improved, but underwent a
relapse after 3 months. Twenty-four-hour measurement of intracranial pressure
revealed elevated values. As a consequence ventriculo-peritoneal shunting was
performed, leading to prominent improvement. Primary PTC can cause acute visual
loss. If conservative treatment fails, different surgical procedures should be
considered.
PMID- 9757424
TI - [MRI findings in Wernicke encephalopathy].
AB - Wernicke's encephalopathy (WE) is a consequence of vitamin B1 (thiamine)
deficiency and in the majority of cases due to alcoholism. We report here the
case of a 26-year-old male alcoholic who had stayed helplessly at home for 4 days
until hospital admission. Clinical diagnosis was difficult due to major
disturbance of consciousness. MRI showed an increase in signal intensity (T2-,
FLAIR-weighted) around the third ventricle, the quadrigeminal bodies, the
fornices, the mamillary bodies, the floor of the fourth ventricle and around the
aqueduct. These findings were indicative of WE although of unusual extent. In
this case MRI correlated well with clinical symptomatology. Therapy with thiamine
was started immediately and symptoms as well as MRI findings resolved partially.
The presented case illustrates the diagnostic usefulness of MRI in WE especially
if the patient is of reduced consciousness and clinical investigation is limited.
PMID- 9757425
TI - [Ictal syncopes. Cardiac sympathetic innervation disorder as the etiology?].
AB - We report 3 cases of an ictal sinus arrest. All patients suffered from temporal
lobe epilepsy (TLE). Seizures were monitored with simultaneous video-eeg during
preoperative epilepsy diagnosis. One patient with cortical dysplasia, who
frequently suffered from long lasting syncopes, had a nearly completely missing
cardiac sympathetic innervation in MIBG-SPECT (=Meta-Iodide-Benzyle-Guanidine
single-photon-emission tomography). Cardiac investigation including long-term ECG
and echocardiography had shown normal findings. After epilepsy surgery the
syncopal events in all patients disappeared. A dominant parasympathetic ictal
stimulus following excitation of the reticular formation might cause the ictal
bradycardia and sinus arrest. A missing sympathetic innervation, possibly
occurring as fehlbildung together with cortical dysplasia, which makes
autoregulation impossible, might then be the explanation for sudden cardiac ictal
death.
PMID- 9757426
TI - [HMG-CoA reductase inhibitor and risk of stroke].
AB - HMG-CoA reductase inhibitors are potent cholesterol-lowering drugs. Recent
clinical trials and meta-analyses show a 30% stroke reduction after treatment
with HMG-CoA reductase inhibitors. Subgroup analyses and experimental findings
support the notion that HMG-CoA reductase inhibitors improve endothelial function
directly by mechanism(s) independent of cholesterol-lowering. They reduce
inflammatory, proliferative and thrombogenic processes in atherosclerotic plaques
and improve endothelial dysfunction. Recent findings demonstrate an enhanced
production of endothelium-derived nitric oxide (NO) by HMG-CoA reductase
inhibitors. Endothelial NO is an important vasodilator and plays a beneficial
role in cerebral ischemic injury. Prophylactic treatment with HMG-CoA reductase
inhibitors in mice selectively upregulates endothelial NO synthase expression and
activity, increases cerebral blood flow at resting state and during ischemia, and
reduces cerebral infarct size after experimental stroke. These findings provide a
novel mechanism for the prophylactic treatment of ischemia-induced cerebral
injury under non-hypercholesterolemic conditions.
PMID- 9757427
TI - [Special presentation on the 90th anniversary of organizing the German Society of
Neurologists in Dresden on 14 December 1907].
PMID- 9757428
TI - [Neurology in the "3rd Reich" and consequences].
AB - This review of German neurology during the Nazi era mentions first the
significance of Jewish neurologists for the history of the specialty, and the
irreplaceable loss that their expulsion from Germany represented. A brief
discussion of the scientific accomplishments of German neurologists during this
time is followed by a description of violations of ethical principles,
exemplified by the human experiments of G. Schaltenbrand. The spirit of the age
exerted a malevolent influence.
PMID- 9757429
TI - History of the surgical treatment of epilepsy.
PMID- 9757430
TI - The diagnosis of the epileptic focus.
PMID- 9757431
TI - Temporal lobe epilepsy.
PMID- 9757432
TI - Dysembryoplastic disorders in neoplastic and non-neoplastic process associated
with temporal lobe epilepsy.
PMID- 9757433
TI - Lesionectomy in surgical treatment of epilepsy.
PMID- 9757434
TI - Multilobar resections in surgical treatment of medically intractable epilepsy.
AB - MATERIAL, METHOD: Authors present the results of surgical treatment in a series
of 93 patients with medically intractable epilepsy and large epileptogenic foci,
in whom multilobar resections have been performed. They constituted 13% of a
group of 716 patients subjected to surgery due to drug resistant epilepsy in the
period 1957-1996, in the Department of Neurosurgery, Medical University of
Warsaw, Poland. Patients treated with multilobar resection constituted the group,
characterised by the most severe course of epilepsy, so they usually had a long
seizures' history at the time of operation (more than 10 years duration of the
disease in 37% of patients), albeit they were qualified to surgery at a
relatively young age (mean age at the time of surgery: 16-th year of life).
Trauma was the most frequent underlying aetiologic factor (perinatal trauma and
other major head injury were documented in 28% and 30% of patients respectively).
Morphological abnormalities of the resected brain tissue were found on
pathological examination (light microscope) in 68% of patients in this series.
RESULTS: Perioperative mortality was 3%. At a follow-up examination (mean follow
up period 7 years postoperatively): 30% of patients were seizure free, in 13% of
patients drug discontinuation was possible. In 23% of patients less than 2-3
seizures per year occurred. So totally in 53% of patients, good result of
treatment was achieved (none or only very rare seizures). In 35% of patients
surgery failed to control seizures' frequency. 9% of patients were lost from
follow-up evaluation. CONCLUSIONS: Multilobar resection (if acceptable from the
clinical point of view) may be an effective treatment choice in patients with
medically uncontrollable seizures and huge epileptogenic foci. This treatment
modality may offer recovery from seizures or significant improvement to 53% of
patients treated. The radical removal of epileptogenic foci, age of the patients
higher than 18 year of life at the time of operation, focal character of EEG
abnormalities and occurrence of only one type of seizures, were found to be good
prognostic factors. On the other hand younger age of the patients operated, the
presence of generalized slow waves in the interictal EEG recordings and the
occurrence of various types of seizures, influenced adversely on the prognosis.
PMID- 9757435
TI - Classical hemispherectomy in treatment of severe form of epilepsy: an analysis of
surgical interventions performed in first years of surgical management of sacred
disease.
PMID- 9757436
TI - Frontal lobe epilepsy: symptomatology and results of surgical treatment.
PMID- 9757438
TI - Kozevnikov's epilepsy--epilepsia partialis continua (results of surgery in 11
patients).
PMID- 9757437
TI - Surgical treatment of intractable parietal lobe epilepsy--our own experience.
PMID- 9757440
TI - Occipital lobe epilepsy.
PMID- 9757439
TI - Chronic drug resistant symptomatic epilepsy starting in early childhood.
PMID- 9757441
TI - Callosotomy in patients with drug-resistant epilepsy.
PMID- 9757442
TI - Cerebellar electrostimulation in patients with drug-resistant epilepsy.
PMID- 9757443
TI - Changes of the quality of life after anterior callosotomy.
PMID- 9757444
TI - CBF evaluation before and after ketamine or brietal activation of the epileptic
discharges.
PMID- 9757445
TI - [The value of structural neuroimaging in the selection of patients for epileptic
surgery].
AB - The aim of this study was to investigate the value of structural neuroimaging
with MRI in the selection of patients for epilepsy surgery. We sought to
determine whether MRI influenced decision concerning resective surgery and
whether MRI provided much more useful information than enhanced CT. MATERIALS AND
METHODS: Neuroimaging studies, MRI and CT, of 300 patients; 265 with partial and
35 with primary generalized seizures, evaluated for surgical treatment of
epilepsy were analysed. The MRIs and CTs were interpreted using visual diagnostic
criteria and findings were correlated with the EEG changes and clinical
semiology. RESULTS: MRIs identified structural lesions in 142, CTs in 96 of all
patients. The clinical semiology (partial seizures), MRI, CT and EEG focal
findings were concordant in 72 cases. The group of 34 patients had resective
surgery. The 7 patients were also operated with MRI and CT focal abnormalities
discordant with EEG changes. Also one patient with primary generalized epilepsy
and temporal lobe lesion (glioma) had resective surgery. MRI studies revealed
structural lesions in 48 patients with normal CT studies. The 43 patients with
partial epilepsy had normal CTs and lesions in MRIs; the 34 cases revealed
correlation with the EEG findings in 29 temporal and 5 extratemporal regions.
Surgery were performed in 23 cases. Also one with partial seizures and MRI
detected hippocampal atrophy was operated, despite of generalized EEG patterns.
In contrast CT revealed two patients with normal MRI and focal changes. The
patients with partial seizures and only CT abnormalities (focal calcifications)
were not operated due to discordant EEG findings. In group of 132 patients with
normal neuroimaging studies and EEG identified seizure focus only 27 had anterior
temporal lobectomy. CONCLUSION: MRI studies gave additional information in case
of 16% patients with intractable epilepsy in comparison with CT findings.
Resective epilepsy surgery was almost twice as often performed when MRIs revealed
structural abnormality. In operated patients, diagnostic sensitivity of
structural MRI, CT and EEG to neurophatology were 70.6%, 46.7 and 92.4%
respectively.
PMID- 9757446
TI - Diagnostic significance of all night physiological sleep EEG records in patients
with drug resistant focal epilepsy.
PMID- 9757447
TI - [The comparison of ketamine with methohexital and thiopental in the
intraoperative EEG in drug-resistant epilepsy].
AB - The acute (ECoG) was examined in 291 patients with intractable epilepsy, without
structural brain lesion--from 1971 to 1997. Temporal lobectomy was performed in
198 cases and extratemporal (frontal, parietal or occipital) in remaining 93
cases to achieve seizure control. Epileptic foci was activated during acute ECoG
by i.v. administration of ketamine (154 cases) or short-acting barbiturates-
methohexital (110 cases) and thiopental (27 cases). RESULTS: Ketamine
significantly more often caused ECoG identified electrographic seizures than
methohexital: p = 0, 00001 or thiopental, which in no cases resulted in seizures.
Also electrographic seizures occurred more frequently after administration of
ketamine in patients with the extratemporal seizure focus localisation in
comparison with temporal focus (p < 0.05). Electrographic seizures provoked after
administration of ketamine improved the localisation of the area to be resected,
more often in extratemporal epileptic foci. CONCLUSIONS: The results of our
investigations indicate that ketamine more effectively activated epileptic focus
than short-acting barbiturates.
PMID- 9757449
TI - The cortical distribution of somatosensory potentials evoked by median nerve
stimulation in patients with epilepsy treated by surgery.
PMID- 9757448
TI - A comparison of Wada test for cerebral speech dominance by use of amytal or
brietal.
PMID- 9757450
TI - The influency of frontal lobectomy on motor pattern in epileptic patients
(Preliminary report).
PMID- 9757451
TI - Difficulties in outcome assessment in surgically treated patients with epilepsy.
PMID- 9757452
TI - Pharmacotherapy of focal epilepsy after surgical treatment.
PMID- 9757453
TI - [Molecular biology of antibodies].
PMID- 9757454
TI - [Indirect anastomoses for moyamoya disease].
PMID- 9757455
TI - [In vitro study on intrathecal application of 5-fluoro-2'-deoxyuridine (FdUrd)
for meningeal dissemination of malignant tumor].
AB - To evaluate the possible clinical intrathecal use of 5-fluoro-2'-deoxyuridine
(FdUrd) for malignant brain tumors, its anti-tumor activity and neurotoxicity
were compared with that of 5-fluorouracil (5-FU) and 5-fluorouridine (FUrd) in
vitro. FdUrd showed good tumoricidal activity against cultured mouse 203 glioma
cells and rat Walker 256 carcinoma cells as well as A172 human glioblastoma
cells. Daoy human medulloblastoma cells and CADO-LC4 human lung cancer cells. It
also showed less toxicity for primary cultures of neurons from C57/BL6 mouse and
human embryo compared to 5-FU and FUrd. Thymidine phosphorylase (TPase) and
thymidine kinase (TK), key enzymes for metabolism of 5-FU derivatives, were
measured in cerebrospinal fluid (CSF). TPase or TK activity was detected in the
CSF of hardly any patients with malignant brain tumors including meningeal
carcinomatosis. These data indicated that the CSF is a favorable site for FdUrd
chemotherapy, because the rate of conversion of FdUrd injected to 5-FU would be
minimal. In conclusion, FdUrd may be potentially useful for intrathecal treatment
of meningeal carcinomatosis.
PMID- 9757456
TI - [Changes in QOL in patients with brain tumors measured by mood changes during and
after treatment].
AB - Patients with brain tumors are exposed to severe stress which may have an
influence on their quality of life (QOL). To measure QOL in those patients, we
measure their mood state during and after the treatments. MATERIALS: 16 patients
who were admitted to our department for treatment of brain tumors, were included
in the study. The tumors included 5 gliomas, 6 meningiomas and others. They were
7 males and 9 females, and age distributed from 19 to 74 years old. All patients
presented more than 90% of the Karnofsky performance score (KPS) on discharge, so
they were expected to return to their previous social life. METHOD: The self
answering tests were performed on admission (Pre), on discharge (Post 1), and at
more than 5 months after the discharge (Post 2). The tests included an original
questionnaire asking consent to admission and treatment, and concerning the
feeling of disability to cope with conditions of living, Cornell Medical Index
(CMI) which measured the neurosis, and Profile of mood state (POMS) which
measured the 6 subscales of patients mood states including tension-anxiety (TA),
depression (D), anger-hostility (AH), vigor (V), fatigue (F), and confusion (C).
RESULTS: The questionnaire showed that the patients feel satisfied with having
consented to the treatment. The feeling of disability to cope with living became
stronger in Post 2 than in Pre. CMI showed a borderline of neurosis in three
patients on admission, and in four patients in Post 2. Only the TA of POMS
subscale improved significantly in Post 2. However, other subscales were
unchanged. It is characteristic that all of the subscales of POMS showed less
disturbance on discharge compared with that on admission, but, they returned to
the Prelevel after they returned to social life. CONCLUSIONS: Patients with brain
tumors have satisfactory consent to the treatment, however, they feel disability
to cope with social life. On discharge, they showed a better mood state compared
to that on admission, but the mood state turned for the worse again during the
follow-up period. It is evident that patients with brain tumors are exposed to
severe stress even after the completion of the treatment. The results necessitate
our taking patients' mental health into consideration for our treatment protocol.
PMID- 9757457
TI - [Extradural temporopolar approach for giant pituitary adenomas invading the
cavernous sinus and parasellar regions].
AB - OBJECTIVE: An extradural temporopolar approach has recently been used in the
treatment of the parasellar, infrachiasmatic, or intracavernous regions. In this
approach, the temporal (superficial) dural layer is separated from the deep layer
(inner cavernous membrane) to expose the cavernous sinus extradurally. We report
our experiences with 5 cases in which a giant pituitary adenoma invading the
cavernous sinus and parasellar regions was resected via the extradural
temporopolar approach. PATIENTS AND METHODS: Between January 1995 and December
1997, 60 patients with pituitary adenomas were operated on at Okayama University
Hospital. The extradural temporopolar approach was used for 5 patients who had a
giant pituitary adenoma invading the cavernous sinus and parasellar regions. The
5 patients were women aged from 32 to 62 years and presented with a visual
dysfunction. Four patients had hormonally non-functioning pituitary adenomas and
one had a growth-hormone secreting pituitary adenoma. RESULTS: The operations
resulted in 1 total, 3 subtotal and 1 partial removal. There was no operative
mortality or major morbidity. Transient oculomotor palsy occurred in 2 cases
postoperatively. This approach provided excellent exposure of the tumor, relevant
cranial nerves and arteries in and around the cavernous sinus through extradural
retraction of the temporal lobe, allowing for sufficient resection of the
intracavernous and parasellar portion of the tumor. Tumors invading the inferior
portion of the clivus or the contralateral cavernous sinus could not be removed
through this approach. CONCLUSION: Our findings suggest that the extradural
temporopolar approach is useful for resection of giant pituitary adenomas
invading the cavernous sinus and parasellar regions.
PMID- 9757458
TI - [Visual acuity outcome and recurrence in large or huge pituitary adenomas
operated with transcranial approach: comparison between frontotemporal and
interhemispheric approaches].
AB - Pituitary macroadenomas which required transcranial removal were reviewed
concerning visual acuity outcome as well as recurrence. We encountered 173
pituitary adenomas of which 27 (15.6%) were removed transcranially during the
past 13 years. Eight cases were excluded due to inadequate information and
improper utilization. Thus, a total of nineteen cases were reviewed in which the
frontotemporal (FT) approach was utilized for seven cases and the
interhemispheric (IH) approach for 12 cases. The mean size and volume of the
tumors in the FT group were 3.0 x 3.7 x 3.1 cm and 18.2 cm3. The main reason for
utilizing this approach was the fact that the tumors extended laterally involving
the unilateral cavernous sinus or that unilateral preoperative visual acuity was
obstructed. The visual acuity outcome was as follows: In six cases showing useful
visual acuity on both sides before surgery, no apparent aggravation on either
side was found in four cases, while in two cases there was complete obstruction
on the operative side. The remaining case showed aggravation on both sides,
though the approach side was decided upon because of the obstructed vision on
that side. The mean size and volume of the tumors in the IH group were 4.6 x 4.8
x 4.9 cm and 71.1 cm3. This approach was used due to the extreme suprasellar
extension because of the large size of the tumors. Although the tumors were
relatively large and the visual acuity was assessed as fair prior to surgery,
visual acuity showed no significant deterioration after the operation and was
found to be satisfactory in 11 out of 12 cases. The complications in the FT group
were oculomotor palsy in 3 cases, hemorrhage in one case, and frontal infarction
in one case. On the other hand, three cases suffered hemorrhage in the tumor
cavity of the IH group, though none needed surgical evacuation. Most of the cases
in the IH group showed pituitary hypofunction following the surgical removal of
the tumors as compared to the cases in the FT group. Recurrence had occurred, in
some cases, several years after the operation. Furthermore, some of the tumors
are still growing larger following only partial or subtotal removal. The prime
aim of the treatment for huge pituitary adenomas which require the transcranial
removal is to retain as much visual acuity as possible. In conclusion, the IH
approach has been shown to be preferable in this situation. The FT approach was
found to be more dangerous in terms of visual outcome than had been expected,
even if the tumors were not particularly large.
PMID- 9757459
TI - [Can EC-IC bypass prevent brain ischemia from recurring?].
AB - The effectiveness of extracranial-intracranial arterial bypass (EC-IC bypass)
surgery for patients with hemodynamic compromise still remains controversial. In
the present study, we evaluated the correlation between the pre- and post
surgical cerebral hemodynamics and long-term prognosis. 28 patients and a
subsequent 21 patients (41 men, eight women: mean age 59.9 [S.D. 8.6] years) with
reduced cerebrovascular reserve due to steno-occlusive disease of the cerebral
major arteries formed the study groups 1 and 2, respectively. Measurement of the
mean hemispheric cerebral blood flow (mCBF) and the cerebral vasoreactivity
(%mCVR) with an intravenous acetazolamide injection were performed by a 133Xe
inhalation method and SPECT. Patients were treated with EC-IC bypass surgery and
measurement of mCBF and %mCVR were made again about one month after surgery. The
patients were observed for a long period (mean 44.3 months). During the follow-up
period, 6 patients experienced recurrent ischemic strokes. The annual incidence
of recurrent ischemic stroke was 4.4%. The patients with significantly reduced
pre- and post-surgical resting mCBF of the affected hemisphere were at
significantly higher risk of recurrent ischemic stroke than the patients with
normal mCBF (p < 0.01). The %mCVR of the affected hemisphere rose after surgery.
PMID- 9757460
TI - [Report of four cases of lymphocytic infundibuloneurohypophysitis].
AB - We reported 4 cases of lymphocytic infundibuloneurohypophysitis. All four
patients had diabetes insipidus as initial symptoms without anterior pituitary
dysfunction. All patients showed pituitary stalk swelling and two patients showed
enlargement of the pituitary gland. No patients were operated on for a
histological diagnosis. No patients received corticosteroid treatment for this
pathology. The mean follow-up period was 36 months. The diabetes insipidus
continued in all cases, but radiological findings showed improvement in all
cases. In one case, adrenal insufficiency occurred after 10 months, but had
disappeared 6 months later. We think lymphocytic infundibuloneurohypophysitis can
be diagnosed without histological examinations and can be treated conservatively
without corticosteroid treatment. It seems to be a self-limiting disease. This
disease can be distinguished from lymphocytic adenohypophysitis, but in some
cases, both the anterior and posterior pituitary glands are invaded, and in this
situation lymphocytic hypophysitis may be an appropriate name. Even if the
initial symptom is diabetes insipidus, careful follow-up is needed for the
duration of the disease.
PMID- 9757462
TI - [Molecular mechanisms of axonal transport].
PMID- 9757461
TI - [Primary intracerebral malignant fibrous histiocytoma with adhesion to a dura: a
case report].
AB - A case of malignant fibrous histiocytoma (MFH) in a 29-year-old man was reported.
CT scans revealed an iso density mass which was homogeneously enhanced by
contrast medium. MRI demonstrated that the right frontal tumor showed slight low
signal intensity in T1-weighted image, and iso signal intensity in T2-weighted
image. Gadolinium-enhanced T1-weighted image showed a homogeneously enhanced
multinodular tumor. Right carotid angiogram revealed a tumor stain fed by the
precentral artery. On operation, en-bloc resection was performed successfully.
Postoperatively, local irradiation of 60Gy was performed. Microscopically,
fibroblast-like cells arranged in storiform pattern were observed, and bizarre
multinucleated giant cells were also observed. Ki-67 labelling index was 54%. We
considered the tumor was a MFH and arose from an intracerebral mesenchymal
tissue. We reviewed some literature and briefly discussed clinicopathological
features and therapy of intracranial MFH.
PMID- 9757464
TI - [MR axonography: application of MRI].
PMID- 9757463
TI - [Evaluation of axonal transport].
PMID- 9757465
TI - [Diseases with axonal flow impairment].
PMID- 9757466
TI - [Gene transduction for experimental brain tumors using recombinant adenovirus
vector].
AB - Recent advances in molecular biology have permitted significant progress toward
the treatment of malignant brain tumors using gene transduction methods.
Adenovirus vectors have recently been shown to transduce genes successfully into
brain tumor cells both in vitro and in vivo. We have investigated the feasibility
of gene transduction for brain tumors using adenovirus vectors. To evaluate in
vitro transduction rate by adenovirus vectors, rat 9L gliosarcoma cells or human
glioblastoma cells were infected with recombinant replication-deficient
adenovirus vectors containing the E. coli beta-galactosidase gene (Adex-CALacZ)
and stained with X-Gal. We observed a multiplicity of infection (MOI)-dependent
rate. Approximately 100% transgene expression was achieved at a MOI of 5 after
seven days of incubation. To evaluate transgene expression in a rat brain tumor
model, AdexCALacZ was stereotactically injected into established rat 9L brain
tumors. Intratumoral injection of AdexCALacZ resulted in high transgene
expression in tumor cells. Although injection of AdexCALacZ in the normal basal
ganglia resulted in broad and diffuse transduction into endogenous neural cells,
direct intratumoral injection resulted in transduction that was relatively
restricted to the tumor cells as well as some neighboring normal cells.
Transduction rates were relatively elevated at the margin of the tumor. Our
results suggest that adenovirus vectors might be a feasible method to transfer
therapeutic genes into malignant brain tumors.
PMID- 9757467
TI - [Superior sagittal sinus thrombosis presenting with subarachnoid hemorrhage in a
patient with aplastic anemia].
AB - A 54-year-old female, who had been treated for aplastic anemia by metenolone
acetate since 1981, developed a sudden unconsciousness in September 1995. On
admission, she was drowny, CT showed a subarachnoid hemorrhage (SAH) in the right
Sylvian fissure. Angiography demonstrated a complete occlusion of the superior
sagittal sinus. The SAH was assumed to be originated from rupture of the right
Sylvian vein, which was irregularly dilated on angiography. The dural sinus
thrombosis was thought to be caused by a long term use of metenolone acetate, and
it was discontinued. But her platelet count dropped due to the aggravation of
aplastic anemia, and she developed repeated hemorrhagic infarction. An active
anticoagulant therapy for the dural sinus thrombosis was thought to be
inappropriate because she had the aplastic anemia and the hemorrhagic infarction
recurred. We have successfully treated this case by mild anticoagulant therapy
with nafamostat mesilate (Futhan).
PMID- 9757468
TI - [A case of impending neuroleptic malignant syndrome associated with Shy-Drager
syndrome].
AB - We report a 55-year-old man with impending neuroleptic malignant syndrome who
showed a remarkable dysautonomia such as dysuria and was treated with L-dopa
under the diagnosis of Shy-Drager syndrome. The patient demonstrated fever,
leukocytosis and elevated serum creatine kinase by a decrease in L-dopa dose.
Probably, he developed impending neuroleptic malignant syndrome, induced by
urinary tract infection as well as decrease in L-dopa dose. Since Shy-Drager
syndrome is often treated with antiparkinsonian drugs, neuroleptic malignant
syndrome can possibly develop after the change in dosage of catecholaminergic
drugs. The imbalance of neurotransmitters and receptors in the central autonomic
nervous system may participate in the development of neuroleptic malignant
syndrome. Accordingly, Shy-Drager syndrome can easily be associated with
neuroleptic malignant syndrome because of its severe disturbance in the autonomic
nervous system. However, autonomic nervous dysfunction, a major sign of
neuroleptic malignant syndrome, might be masked by symptoms of Shy-Drager
syndrome. Therefore, diagnosis of neuroleptic malignant syndrome is often
delayed. Careful observations of patients with Shy-Drager syndrome related with
an antiparkinsonian drug are necessary, especially when the dose of drugs is
changed or the general condition deteriorates.
PMID- 9757469
TI - [Usefulness of aspiration surgery for elderly patients with hypertensive
cerebellar hemorrhage].
AB - We report two cases with hypertensive cerebellar hemorrhage who were successfully
treated with frameless stereotaxic aspiration. First case, an 85-year-old man
with hypertension had a large-sized hematoma in left cerebellar hemisphere.
Emergency aspiration for cerebellar hemorrhage was carried out through a
suboccipital burr hole. He had a good recovery at discharge. Second case, an 84
year-old female with hypertension showed right cerebellar hemorrhage. She had
been in somnolence state for one month with conservative treatment. Then,
aspiration surgery for the hematoma was carried out through a suboccipital burr
hole. Her neurological condition was ameliorated. Frameless stereotaxic
aspiration for cerebellar hemorrhage through suboccipital burr hole is less
invasive and useful procedure, especially for elderly patients.
PMID- 9757471
TI - [A case of measles encephaloneuropathy in a pregnant women].
AB - We reported a patient with measles encephaloneuropathy. A 26-year-old woman in
her 15th week of gestation became febrile and developed cutaneous eruption
typical of measles on July 1 1997. Five days after appearance of the rash, fetal
death was identified and the fetus was removed. Following the operation, she
became comatous. Neurological examination revealed neck stiffness, flaccid
paralysis of the four limbs, and decreased sweating in the lower limbs. CSF
protein was 143 mg/dl with cell count of 1365/mm3. Myelin basic protein in CSF
was positive. High titers of antimeasles antibodies were found in the serum and
the cerebrospinal fluid. EEG revealed a predominance of slow waves. In MRI
obtained earlier in her illness, high signal intensity areas were noted to spread
in the brain stem and external capsule on T2-weighted images. However, T1
weighted image was unremarkable. Serial electrophysiological studies suggested
demyelination of the motor nerves. With combination of methylprednisolone and
immunoglobulin therapy, she made a remarkable recovery without any neurologic
sequelae. We believe that the measles encephalitis in our patient is
predominantly demyelinating due to an immunologic reaction in a
pathophysiological aspect. We should pay attention to coincident poly
radiculoneuropathy in the early stage of measles encephalopathy.
PMID- 9757470
TI - [A case of glioblastoma manifesting 49 years after lobotomy].
AB - We report a case of glioblastoma manifesting 49 years after a lobotomy. He was
diagnosed as having schizophrenia at age 20 and was operated on with a standard
lobotomy when he was 27 years old. He had led a useful life after 40 years old
without medication. Because of hallucination and delusion, he was hospitalized at
the end of 1996. CT showed a well enhanced tumor adjacent to the cavity made by
the lobotomy in the left frontal lobe. This is the second case report of
glioblastoma just beside the cavity formed by lobotomy. The relationship between
glioblastoma and old lobotomy is discussed, especially in regard to morphology
and CT findings.
PMID- 9757472
TI - [A case of neurologic type of Wilson's disease with increased aluminum in liver:
comparative study with histological findings to metal contents in the liver].
AB - Histological findings and metal contents in the liver were studied in a patient
with neurologic type of Wilson's disease. Copper and aluminum contents in the
biopsied liver of the patient with Wilson's disease were measured simultaneously
by neutron activation analysis at Research Reactor Institute, Kyoto University.
Four cases of adult cirrhosis were selected as the control for cirrhosis and five
cases of adult liver as the control for neurologically normal. The biopsied liver
showed markedly increase in the copper content (814.4 micrograms/g: dry weight)
and extremely high content of aluminum (479.4 micrograms/g: dry weight), compared
to those of the controls. On the other hand, macroscopically no cirrhosis was
observed and the characteristic appearances of macronodular cirrhosis failed to
detect histologically. Interestingly the fibrosis or inflammation of the liver
was seen faintly. It is likely that toxic metals in the liver such as aluminum,
copper and manganese might be implicated in the pathogenesis of neurologic type
of Wilson's disease.
PMID- 9757473
TI - [Kernohan notch].
PMID- 9757474
TI - [Radiologic emergency management in multiple trauma cases].
AB - The management of multiple trauma patients has improved recently. Surgeons'
education, preclinical rescue structures, initial clinical survey and therapeutic
strategies, as well as diagnostic imaging, have progressed. Plain film imaging is
increasingly being abandoned in favor of CT. Fast imaging techniques (spiral CT)
have led to the inclusion of CT in the primary survey. To minimize the risk to
the patient during prolonged diagnostic time, algorithms have to be defined
concerning structures, emergency room equipment and quality. Basics, state of the
art and suggestions concerning management of multiple trauma patients are
presented and discussed from the radiologist's point of view.
PMID- 9757475
TI - [Diagnostic imaging of acute head and brain injuries].
AB - The role of neuroimaging in the acute setting of head trauma is to diagnose the
extent of intracranial injury and to identify all lesions which require urgent
neurosurgical treatment. Computed tomography (CT) remains the most important
diagnostic tool for initial screening of trauma victims. Although magnetic
resonance imaging (MR) has higher sensitivity to most traumatic lesions than CT,
due to the ease and speed of CT, and the fact that sufficient monitoring of
critically ill patients during the examination is much easier with CT than with
MR, mean that MR is not the imaging modality of choice for the initial diagnostic
work-up. Recent MR techniques such as FLAIR or diffusion imaging further improve
the sensitivity of MR in head trauma. Conventional angiography is currently
indicated only for few suspected vascular lesions (e.g. traumatic arterio-venous
fistulas, vascular dissections).
PMID- 9757476
TI - [Trauma of the facial bones and skull].
AB - Facial trauma is frequent and mainly caused by motor vehicle accidents. Due to
this main etiologic factor, trauma to the facial skeleton is often associated
with serious injuries, commonly involving the brain, chest or abdomen. As a
consequence, the initial clinical management of these patients includes control
of hemorrhage and immediate assessment of life-threatening injuries, including
the maintenance of the airways. Patients presenting with facial trauma are
initially evaluated with a systematic clinical examination because many fractures
can be accurately diagnosed by inspection and palpation alone. In these cases
plain film radiographs serve only for confirmation and documentation of the
diagnosis. In many other cases accompanying and extensive soft tissue swelling
may clinically obscure fractures. A complete and accurate evaluation of these
patients requires additional radiological imaging methods. A series of plain
films may be generally sufficient but in most of the cases they can be regarded
as initial screening methods for more thorough diagnosis with computed tomography
(CT). In trauma patients CT is the imaging method of choice because it shows more
fracture lines and displaced fragments than any other imaging modality. CT
delineates soft tissue and bony structures and can localize and even characterize
foreign bodies. A complete and accurate characterization of the fracture type and
potentially associated complications in mandatory for the appropriate treatment
and can only be achieved by careful radiological (CT) evaluation.
PMID- 9757477
TI - [Spiral CT and conventional CT in the preoperative imaging of intraocular metal
foreign bodies].
AB - PURPOSE: To compare the effectiveness of spiral CT versus conventional CT in the
preoperative assessment of metallic intraocular foreign bodies. METHODS: Eighteen
patients with penetrating eye injuries and suspected metallic intraocular foreign
bodies were assigned to undergo either spiral CT or conventional CT in the axial
plane. The spiral and the conventional CT data were transferred to a workstation,
and reconstructions in the coronal and sagittal planes were performed. Additional
direct coronal scanning was performed only when necessary for preoperative
assessment. The quality of the axial as well as the reconstructed coronal and
sagittal images was assessed for each imaging modality. The size of the foreign
bodies was measured and compared to the actual diameter. Total examination time
and radiation dose delivered to the lens were measured for each imaging modality.
RESULTS: All foreign bodies were detected by each scanning modality on the axial
and on the reconstructed planes. The quality of the axial images was similar for
spiral and conventional CT. The spiral technique provided high-quality
reconstructed images which allowed accurate localization of the foreign bodies in
all cases. Reconstructions by conventional technique were inadequate for
preoperative assessment. The examination time for the total orbital volume was 18
s for spiral CT and 52 s for conventional CT. Radiation dose delivered to the
lens was 35 mGy for spiral CT and 56 mGy for conventional CT axial scanning.
CONCLUSION: Spiral CT multiplanar imaging offers several significant advantages
for the preoperative assessment of metallic intraocular foreign bodies compared
to the conventional CT technique in clinical practice, including short
examination time, minimized motion artifacts, reduced radiation exposure, and
accurate localization.
PMID- 9757478
TI - [Spinal trauma].
AB - In the workup of patients suffering from spinal trauma the radiologist is eager
to make a proper diagnosis asking only for few additional examinations. This can
be done by a functional and biomechanical approach in reading standard
radiographs. With the knowledge of the kind of injury expected the whole extent
of posttraumatic changes in the spine can be delineated exactly. The goal is to
make a diagnosis that answers questions of stability so the traumatologist can be
aided in therapy.
PMID- 9757479
TI - [Radiologic imaging of thoracic trauma].
AB - Blunt trauma to the chest results from the transfer of kinetic energy to the
human body. It may cause a wide range of mostly life-threatening injuries,
including fractures of the thoracic skeleton, disintegration of the pleural
space, contusion or laceration of pulmonary parenchyma and damage to the
mediastinal structures. For a systematic approach it may be helpful to follow an
organ-based evaluation of thoracic trauma. However, it should be borne in mind
that subtle injuries may be associated with serious complications. Trauma to the
chest may affect different anatomic compartments at the same time, requiring an
extending diagnostic approach. Conventional radiography plays a major role in
diagnosing thoracic trauma, complemented by ultrasound examination of the pleura
and abdomen. It is well documented that CT scanning represents a major
technological improvement for assessment of thoracic trauma. With the advent of
fast helical CT scanning this method becomes more applicable for severely
traumatized patients and potentially replaces other time-consuming procedures.
State-of-the-art imaging of both projection and cross-sectional techniques
provides useful information for immediate and appropriate treatment mandatory in
patients with thoracic trauma.
PMID- 9757480
TI - [Radiologic diagnosis of abdominal trauma].
AB - In Europe ultrasonography has displaced diagnostic peritoneal lavage (DPL) in the
primary survey of polytraumatized patients with suspected abdominal trauma.
Hemodynamically unstable patients who are brought to the emergency room with
blunt abdominal trauma will go directly to the operating room after a rapid
ultrasonography examination with evidence of hemoperitoneum. In hemodynamically
stable patients, in addition to ultrasonography, computed tomography can be done.
This is especially efficient if evaluation with sonography is not completely
possible or shows little pathology (e.g. small amounts of hemoperitoneum).
PMID- 9757481
TI - [Pelvic ring injuries].
AB - PURPOSE: Analysis of the trauma patient of fractures of the pelvic ring and
classification according to AO/Tile. METHODS: 125 unselected patients (43
females, 82 males) were evaluated retrospectively by conventional x-ray, and CT
examinations included follow-studies. RESULTS: Type-A fractures were seen in 36
(29%), Type-B fractures in 58 (46%), and Type-C fractures in 31 (25%) cases. Type
B and Type-C fractures mainly occurred in patients with traffic accidents and
falls from great height. Type-A fractures were seen most often in patients with
accidents at home or at work. However, in patients with complex fractures a
classification concerning Type-B or Type-C fractures was difficult. SUMMARY:
Based on CT criterias, in most patients a statement concerning the applied
forces, the stability of the pelvic rim and the fracture type can be made.
PMID- 9757482
TI - [High-flow priapism following blunt perineal trauma. Interventional therapy].
AB - A 10-year old boy developed an arteriocavernosal fistula with a permanent penile
erection (high-flow priapism) after a blunt perineal trauma. The diagnosis was
established by Doppler ultrasound, blood gas analysis and angiography. A
conservative treatment attempt with penile cooling and puncture of the cavernosal
corpera with blood aspiration and etilefrine instillation failed to resolve the
priapism. An embolization of both bulbocavernosal arteries was followed by an
immediate detumescence. Normal functional erection was preserved. No recurrence
was observed during a follow-up of 6 months.
PMID- 9757483
TI - [Unclear shoulder pain].
PMID- 9757484
TI - [Acceptance: scientific cultural aspects].
AB - In highly developed industrial societies the acceptance of risk is in decline.
The reasons for this are connected in elementary fashion with the fact of modern
life. Their effects may be considered irreversible, and pep talks under the motto
"dare to risk!" are probably of no avail; we must adapt ourselves to declining
risk acceptance. What are the reasons for it?
PMID- 9757485
TI - [Evaluation of respiratory muscles].
AB - Respiratory muscle weakness may be the sole cause of dyspnea or may aggravate
dyspnea due to another respiratory disease, and is often difficult to recognise
clinically. The assessment of respiratory muscles should follow a graded approach
using tests of increasing complexity. Clinical examination should look for
dyspnea, orthopnea, morning headache, daytime somnolence, fatigability,
tachypnea, abdominal, or rib cage paradox, and amyotrophy. Imaging is useful in
diagnosing diaphragmatic paralysis using chest radiograph, fluoroscopy or
ultrasound. In cases of moderate to severe respiratory muscle weakness, lung
volumes show reduced vital capacity and total lung capacity. Measuring the change
in vital capacity from sitting to supine position is useful since it shows a 25
50% fall in cases of diaphragmatic paralysis. The specific and classical tests of
respiratory muscle strength are maximum inspiratory and expiratory pressures (MIP
and MEP) sustained during one second against near complete occlusion. Sniff nasal
inspiratory pressure (SNIP) is a new and easier test of inspiratory muscle
strength. Normal values obtained with these simple tests rule out clinically
significant respiratory muscle weakness. In case of doubt, more complex and
invasive tests can be used such as transdiaphragmatic pressure and magnetic
stimulation of the phrenic nerves.
PMID- 9757486
TI - ["Multiple chemical sensitivity syndrome"].
AB - Multiple chemical sensitivity (MCS) has been described as an acquired multiple
organ disease typically characterized by central nervous irritative and/or
gastrointestinal symptoms. Advocates of this suspected syndrome attribute these
disorders to overstressing of the organism caused by exposure to external noxae.
Opponents of the theory of MCS attribute all the symptoms to classical
conditioning or other psychopathological processes. In so far as controlled data
exist, there is no indication of a toxic or immunological cause for this
syndrome.
PMID- 9757487
TI - [Aerosol therapy].
AB - Aerosol therapy plays a major role in the diagnosis and treatment of various lung
diseases. The aim of inhalation therapy is to deposit a reproducible and adequate
dose of a specific drug to the airways, in order to achieve a high, local,
clinical effect while avoiding serious systemic side effects. To achieve this
goal, it is therefore important to have an efficient inhalation device to deliver
different medications. However, the currently available therapeutic inhalation
devices (nebuliser, pressurised metered-dose inhaler and dry powder inhaler) are
not very efficient in aerosol delivery and have several disadvantages. Inhalation
devices can be assessed by in vitro studies, filter studies and radiolabelled
deposition studies. Several radiolabelled deposition studies have shown that
nebulisers and pressurised metered-dose inhalers are not very efficient in
aerosol delivery. In children, before 1997, only 0.5% to 15% of the total
nebulised or actuated dose from a nebuliser or pressurised metered-dose inhaler
actually reached the lungs. These numbers were somewhat improved in adults, 30%
of the total nebulised or actuated dose reaching the airways. Aerosol therapy
with dry powder inhalers was the most efficient before 1997, 30% of the total
dose being deposited in the lungs of adults and children. In 1997, new
developments in pressurised metered-dose inhalers much improved their efficiency
in aerosol delivery. Lung deposition can be increased by up to 60% with use of a
non-electrostatic holding chamber and/or a pressurised metered-dose inhaler with
a hydrofluoroalkane propellant possessing superior aerosol characteristics.
Several studies comparing the clinical efficiency of different inhalation devices
have shown that the choice of an optimal inhalation device is crucial. In
addition to the aerosol characteristics, ventilation parameters and airway
morphology have an important bearing on deposition patterns. These parameters may
be greatly influenced by the patient's acceptance of a specific inhalation device
and therefore determine the choice of the device used. It is important for the
clinical impact to develop more efficient inhalation devices, which need to be
assessed for use in different age groups. These devices should be cheap, easy to
use, portable, usable with all medications and environmentally safe.
PMID- 9757488
TI - Bronchiectasis.
PMID- 9757489
TI - [Morbid obesity: 130 consecutive patients with laparoscopic gastric banding].
AB - Morbid obesity causes co-morbidity such as diabetes mellitus, hypertensive heart
disease, sleep apnoea, degenerative bone diseases and increased incidence of
malignancy. Life expectancy and quality of life are reduced significantly.
Without adequate weight loss, treatment of co-morbidity remains symptomatic only.
Surgical treatment of morbid obesity is the one therapy promising long-term
success, since conservative procedures normally lead to recurrence of overweight.
We performed laparoscopic gastric banding on 130 patients between 1.11.95 and
31.10.97. Mean overweight was 63 +/- 12.7 kg (SD), and mean BMI was 46.5 +/- 4.6
kg/m2. The average hospital stay was 5.5 +/- 1.5 days. 4 patients with
postoperative pulmonary embolism were treated with oral anticoagulation. We
performed 9 (6.9%) reoperations because of pouch dilatation or dorsal slipping
with food intolerance in the first series of 70, and none in the second series of
60 patients. Median weight loss after 3 months was 14.7 +/- 4.2 kg, after six
months 24.0 +/- 6.6 kg and after 12 months 33.2 +/- 8.5 kg, corresponding to
excessive weight loss (EWL) of 55.9 +/- 14.8% in the first year. 14 (70%) of 20
patients with diabetes mellitus normalised and 6 patients with diabetes mellitus
normalised and 6 patients showed improved blood sugar levels. All 36 patients
with hypertensive heart disease had normalised blood pressure, 60% of them
without further medical antihypertensive treatment after median EWL of 36%.
Cholesterol levels normalised in 30 (57%) patients and improved in 20 (38%) after
6 months. Laparoscopic gastric banding is a suitable method for reducing weight
in morbid obesity patients and provides a better quality of life in a group of
patients who are carefully evaluated and followed. Reducing co-morbidity and
improving ability to work have a positive economic impact on health care costs.
PMID- 9757490
TI - [Molecular physiology and pathophysiology of renal phosphate excretion].
AB - The kidney is a key organ in phosphate homeostasis. Phosphate excretion is
largely determined by free glomerular filtration and by regulated reabsorption in
the proximal tubule. The cellular/molecular mechanisms involved in phosphate
reabsorption have been elucidated in great detail over the past few years. A
brush border membrane protein with most probably 8 membrane-spanning regions
represents the rate-limiting and physiologically/pathophysiologically modified
transport mechanism. Altered phosphate reabsorption correlates with an altered
brush border membrane transporter protein content, altered either by new
synthesis/membrane insertion or by membrane retrieval/degradation. Current
knowledge on the molecular/cellular level is a prerequisite for an understanding
of kidney based alterations in phosphate homoeostasis.
PMID- 9757491
TI - [ 40 years of 5-fluorouracil--still an attractive cytostatic].
AB - On its 40th birthday 5-fluorouracil (FU) is still an attractive drug frequently
employed in adjuvant and palliative treatment of colorectal and breast cancer,
head and neck cancer, oesophageal cancer and anal cancer. After all this time it
is still not known what the optimal schedule or the best form of administration
is, and whether or not modulation of the drug is of any benefit. This article
deals with the drug's different modes of action depending on the schedule of
administration. An overview of the literature on drug modulation is given. We
introduce the less well-known side effects of the drug and the newly developed
orally administered prodrugs of FU.
PMID- 9757492
TI - [Extrinsic allergic alveolitis: a review for the practitioner].
AB - Extrinsic allergic alveolitis (EAA) or hypersensitivity pneumonitis (HP) is a
clinical syndrome characterised by an inflammatory, partly granulomatous, immune
disorder involving interstitial and alveolar spaces secondary to inhalation of
organic substances. The disorder is mainly due to occupational exposure, farmer's
lung being the best-known example. Acute, subacute or chronic forms can be
clinically differentiated. Given the fact that chronic forms may present a
pattern of irreversible pulmonary fibrosis, clinicians must be aware of the
diagnosis of EAA in every situation where the history shows a potential antigenic
exposure. Prevention should be reinforced by increasing individual protective
measures and by improving techniques used at the workplace.
PMID- 9757493
TI - [Farmer with osteomalacia?].
PMID- 9757494
TI - Implementing the North Karelia Project in Scotland.
AB - A comprehensive, determined and theory-based community programme can have a
meaningful and positive effect on risk factors and life styles. In much the same
way as the North Karelia Project was rolled out to cover the whole of Finland,
there is no reason why our intervention schemes could not be rolled out to cover
the whole of Scotland. The North Karelia Project proved that a major national
demonstration programme can be a strong tool for favourable national development
in chronic disease prevention and health promotion.
PMID- 9757495
TI - Falls in old age: inevitable or preventable?
PMID- 9757496
TI - Medical schools in the new millennium.
PMID- 9757497
TI - Scottish Hypothermia and Rewarming Project (SHARP)
PMID- 9757498
TI - Minor morbidity after day-case surgery.
PMID- 9757499
TI - The dangers of taking 'T in the country'.
AB - 'T in the Park' is the largest annual music festival in Scotland. This paper
reports on how an increased attendance and change of location for the 1997 event
altered the workload. The influences that affected the pattern of patient
presentations and the adaptations made in the medical service provided are
discussed.
PMID- 9757500
TI - Neutralising IL-12 activity as a strategy for prolonging allograft survival and
preventing graft-versus-host disease.
AB - Interleukin-12 (IL-12) is a key immunoregulatory cytokine which promotes the
development of Thl-dependent, cell-mediated immune responses. Acute allograft
rejection after organ transplantation and acute graft-versus-host disease (GVHD)
after bone-marrow transplantation are generally attributed to cell-mediated
immune mechanisms and, therefore, potentially susceptible to immunological
intervention at the level of IL-12. Recent data from murine models of
transplantation have highlighted the potential of IL-12 as a selective target for
immunotherapy. Neutralising endogenous IL-12 for a brief period at the time of
transplant promotes long-term deviation from a Th1 to a polarised Th2 alloimmune
response. This confers lasting protection from GVHD but is less effective at
preventing acute rejection, possibly because Th2-dependent immune responses are
also capable of effecting graft rejection.
PMID- 9757501
TI - A retrospective epidemiological analysis of non-accidental head injury in
children in Scotland over a 15 year period.
AB - A retrospective analysis of the epidemiological characteristics of non-accidental
head injury (NAHI) in children in Scotland over the last fifteen years from 1981
until March 1996 was performed. The information was provided by the Information
and Statistics Division of the Scottish Health Service. The average incidence of
NAHI calculated over this period was 0.04 cases per year per 1000 children under
5 years. Fifty-five per cent of all cases occurred in those children who were
less than a year old. 41% of cases were inflicted by a parent but in 47% the
perpetrator could not be identified. The mortality rate was found to be 2%. Non
accidental head injury cases identified using the ICD-9 coding classification
system gives a surprisingly low incidence. This number is probably an
underestimate and the reasons for this are discussed. A prospective
epidemiological analysis of NAHI in children in Scotland is being undertaken to
determine the true incidence.
PMID- 9757502
TI - Early diagnosis of hepatocellular carcinoma in haemochromatosis influences
surgical management.
AB - Using case note review, a retrospective analysis was carried out of all patients
referred with haemochromatosis and suspected hepatocellular carcinoma between
1988 and 1997 to define the mode of presentation, management and outcome of such
patients. All 12 patients were male with a mean age of 67 years. Four patients
presented whilst asymptomatic by alpha-fetoprotein screening. Mean time interval
between diagnosis of haemochromatosis and hepatocellular carcinoma was 6.7 years.
One patient underwent right hepatectomy, seven patients were treated by
chemoembolisation and the remaining four patients were treated symptomatically.
The median survival of the chemoembolised patients was 13 months. Of those
patients treated symptomatically, the median survival was four months. Screening
for hepatocellular carcinoma is often not undertaken in patients with
haemochromatosis. Survival prospects are poor in patients whose tumour presents
symptomatically.
PMID- 9757503
TI - Visual loss in a returning traveller with tick typhus.
AB - Rickettsial diseases are increasingly found world-wide and should be considered
in febrile patients returning from abroad. This case report describes the
vasculitic complications of a patient returning from the Republic of South Africa
with tick typhus.
PMID- 9757504
TI - A melange of meningiomata.
AB - Eight case reports of elderly patients with meningiomata are presented. Their
mode of presentation to a typical district general hospital in central Scotland
and subsequent clinical management is described. The significance of these cases
is discussed.
PMID- 9757505
TI - The witch doctors of Scotland.
AB - To investigate beliefs about healing in early modern Scotland, records of 61
witch trials were examined. Thirty-three were found to include healing in the
charges. Seventeen described cures involving black magic, in which disease
supposedly caused by the witch was removed or illness was transferred to another
individual. Twenty-two included cures by white magic, i.e. herbal remedies and
non-harmful magical rites. Most cases citing cures by black magic included
charges of other black magic. However, several trials describing white magical
cures make no mention of black magic. Most of the accused were probably
implicated through confessions by other witches. Others may have had psychiatric
problems and made fantastical statements. Some were antisocial individuals
reported as witches by neighbours. Few were tried primarily for their healing
activities.
PMID- 9757506
TI - Royal College of Physicians of Edinburgh. Consensus Conference on Medical
Management of Stroke. 26 & 27 May 1998.
PMID- 9757507
TI - [Personal growth between psychotherapy and pedagogy].
AB - The relationship between of psychotherapy and education is full of tension. Both
have similar patterns of action. If one wants to define their relationship, the
Telos of the respective practice has to be determined. Pedagogy has to be
concerned with human formation in all its forms of action, and can only be
executed by each individual him/herself; it is therefore above the principle of
dialogue. This not only applies to tuition which is linked to personal insight,
but also to education, which is tied to self-determination.
PMID- 9757508
TI - [Anxiety of physicians about addiction therapy].
AB - An analysis of reasons why many physicians show considerable reservations towards
sufficient diagnostic and treatment measures of alcohol-related disorders
produced several factors: (a) guilt and aggression are linked to addictive
disorders in an unproportional way, exceeding the common disease concept; (b)
defense mechanisms on the part of the physician as well as the patient impair the
therapeutic relationship. (c) Motivation and treatment of alcoholic patients
could be improved by offering Balint groups, therapeutic supervision and
intensified training of physicians.
PMID- 9757509
TI - [Finding meaning in the final phase of life].
AB - The last phase of life presents for every human being an enormous challenge. This
also applies to relatives and those who look after the person concerned. The need
to give meaning to this consciously lived space of time is made clear when we
look at the wishes expressed, in more or less the same way, by many seriously and
terminally ill. In the following article it is tried to highlight this giving of
meaning by showing the wishes most often expressed and to give examples from
practical work.
PMID- 9757510
TI - [Musical dialogue--music therapy in social contact disorder and communication
difficulties].
AB - Musical dialogue is a way of leading people incapable of speech out of their
isolation and difficulty of expression and of helping early emotionally disturbed
people to get in contact with their feelings. Video excerpts of therapy sessions
with 3 autistic children show how basic capabilities for interpersonal dialogue
are made possible through music therapy.
PMID- 9757511
TI - ["Now tell me, what is your orientation to religion?"--Therapeutic attitude and
management as an expression of religious faith].
AB - The essence of the therapeutic process is the relationship: the client
experiences that the therapist is prepared "to be there" and to remain with
him/her on the journey unconditionally. A possible goal of personal life, as well
as of a therapeutic process, is to become oneself. This is described in the
biblical symbol of Exodus: the motivation of the way and all existential
experience of being on the way are a possibility to interpret my human existence
and to fit it into the wider horizon of religious understanding; to know and
experience a liberator-God (a God who sets me free) as the very basis of my
development. To what extent therapy--as part of the way the therapist and the
client go together--always also touches a religious dimension is shown by giving
examples of some attitudes and consequent actions.
PMID- 9757512
TI - [Psychiatry and psychotherapeutic medicine].
AB - Starting from a sketch of the basic view points from which the topic will be
elucidated, the author focuses on the different logics of psychiatry and
psychotherapies. The connections between the topic and the somatopsychosocial
model, the intercorrelation of psycho-genetic interpretative models and
indication for psychotherapy indicate an approach which is oriented towards the
disordered person (and not the disorder). This concept is compared with the often
used definition of psychotherapy by Strotzka. The dependence of the concept on
traditions in psychiatry (Krafft-Ebing, Jaspers, Kretschmer, E. Bleuler, and M.
Bleuler) and its consistency with modern multiaxial diagnostic systems (Frances
et al.) are stressed. Finally the border to psychotherapeutic medicine outside
psychiatry, both in theory and practice, is stressed.
PMID- 9757513
TI - [Intuitive dialogue--a way out of emotional blockages with defocusing
imagination].
AB - Intuitive dialogues allows to loose trauma-, conflict-, and subject-fixations.
The defocusing imagery plays an important part role in this method. The
metaphorical method is oriented on Winnicott, M. Balint, and on Ernesto Grassi
and on the theory and praxis of modern art-therapy. A specific Balint group in
the dying scene is described, in which role- and relationship conflicts are
defocused in form of a mood oriented sensory-metaphorical process. Finally the
theory and method of the intuitive dialogue is discussed, especially in the
therapy with tortured patients.
PMID- 9757514
TI - [Comparative study for assessing quality of life of patients with exogenous sleep
disorders (temporary sleep onset and sleep interruption disorders) treated with a
hops-valarian preparation and a benzodiazepine drug].
AB - This randomized, double-blind, controlled clinical trial in parallel group design
demonstrated equivalent efficacy and tolerability of a hop-valerian preparation
compared with a benzodiazepine preparation in patients suffering from sleep
disorders according to DSM-IV criteria. Sleep quality, fitness and quality of
life were determined by psychometric tests, psychopathologic scales and sleep
questionnaires at the beginning of the therapy, end of therapy (duration 2 weeks)
and then 1 week after cessation of therapy. Patients' state of health (4-point
scale) and medication tolerability (occurrence of adverse events) were
documented. Using the following as parameters "Alphabetischer Durchstreichtest,
Feinmotoriktest, Befindlichkeitsskala, Beschwerdeliste, Schlaffragebogen A and B"
the differences between beginning and the end of the therapy were analyzed by
simultaneous testing of the equality or superiority of the test preparation. The
equivalence of both therapies according to sleep quality, fitness and quality of
life was proven by a Mann-Whitney-Statistic of 0.50 with a lower boundary of the
95% confidence interval of 0.46. The patients' state of health improved during
therapy while showing a deterioration after cessation with both preparations.
Withdrawal symptoms, however, were documented with benzodiazepine. Only one
adverse drug reaction was reported during this study, namely stomach complaints
from both the test and reference medication. This study shows that the
investigated hop-valerian preparation in the appropriate dose is a sensible
alternative to benzodiazepine for the treatment of nonchronic and non-psychiatric
sleep disorders.
PMID- 9757515
TI - [Urinary incontinence in neurogenic defects and urogenital anomalies in
childhood].
AB - Dysraphic defects may cause neurogenic incontinence in childhood. Constipation
and encopresis are often associated. Depending on the involved segment of the
spinal cord hyperreflexia or atonia of the detrusor is observed. Similar
findings, without anatomic correlation, can be seen in occult-neurogenic voiding
dysfunctions. Therapeutic means aim at preservation of kidney function and the
best possible continence. If the symptoms cannot be treated by anticholinergic
drugs in a low-capacity, hypertonic bladder, augmentation by bowel segments or
continent urinary diversion (e.g. Mainz I pouch) is performed. In the last years
modalities of clean intermittent self-catheterization in high-capacity, atonic
bladders could be enhanced by the development of new atraumatic catheter systems.
Urogenital malformation e.g. proximal epispadias and exstrophic bladder can cause
incontinence as well. Recently, new therapeutic concepts were introduced. Ectopic
ureter (extraurethral incontinence) in girls or posterior urethral valves in boys
as a reason for incontinence must not be forgotten.
PMID- 9757516
TI - [Incontinence, dementia and multiple morbidity--predictive factors for nursing
care requirement and nursing home admission].
AB - The present survey monitored all new admissions to 4 homes for the aged/nursing
homes in the area of Velbert/Neviges (Nordrhein-Westphalia, Germany) over a 12
month period in 1996 and 1997, respectively. The study concentrated on the
importance of incontinence, dementia and comorbidity when predicting need of care
and removals to nursing homes. The statistical evaluation reveals a net coherence
between dementia, nursing level and incontinence, and stresses the importance of
these factors for the nursing home situation in Germany as the position
increasingly develops into providing for and serving a clientele which is dement
and heavily in need of care. Furthermore, the evaluation clearly shows that
incontinence is still taboo to doctors as well as to their patients, and that, in
spite of the medical and economical importance, the affected and their relatives
are generally poorly informed. The described results imply a change in how to
treat incontinence, dementia and comorbidity and should lead to renewed
therapeutical concepts.
PMID- 9757517
TI - [Out-patient hospice services--their importance for palliative care in Germany].
AB - Hospice services can be divided into three groups. Few institutions deliver the
full scope of palliative home care, most of the others can provide considerably
less. The third group of services are those that do not support patients but aim
to establish a home care service or a hospice. In February, 1997 396 home care
services were working in Germany. 48 of these services provided palliative home
care, 69 services were hospice initiatives. The scope of services rendered is
very broad and reaches from psychosocial support to complex medical tasks. In the
last year, 13,700 patients have been supported at home by hospice services in
Germany. Palliative care services usually have professional staff, but they would
not be able to work without honorary help. Beside of support for patients and
relatives tasks of the home care service are the coordination and exchange
between in-patient units, general physicians and social care ward. By cooperation
with all institutions for out-patient and home care as well as with general
physicians, they contribute to avoid in-patient treatment for their patients.
Another important function is to spread the hospice idea and work as multipliers
for knowledges and attitudes in palliative care. The number of home care services
available in Germany is not sufficient. Only 48 institutions can be ranked as
palliative care services. The distribution of the hospice services in Germany is
very irregular, and providers of home care services are even more scarce in the
eastern part of Germany.
PMID- 9757518
TI - [Strategies for the application of quality control in intensive care nursing].
AB - The lack of transparency in nursing duties leads to a reduction in nursing staff,
particularly among highly trained nurses who have an increased responsibility for
patient care. A requirement for quality patient care in the future for intensive
care nurses is to increase transparency of the establishment and evaluation of
indicators clearly documented in a catalogue of basic and process standards.
Defining these standards in a framework of necessary and optional care allows for
cost-benefit-analyses and, on the other hand, departmental reorganisation. This
catalogue provides the best patient care because it is based on clearly
established, comprehensive standards and on latest developments in medical and
nursing research.
PMID- 9757519
TI - [Strategies for coping with complex problems. Importance of an integrated
practice to the quality of life in patient care].
AB - Due to the demographic shift, increasing care needs of elderly and chronically
ill people have growing impact on the health care services. With complex needs to
meet, the quality of life of patients depends on multiple factors, of which the
continuity of care plays an important role. Integrated care requires the exchange
of information and close coordination on the concept of care between all
participants in the care process. Yet, collaborative care is often seriously
jeopardized by lack of knowledge about the concepts, scope of action and requests
of the involved health professionals and services. Information on the past and
present health state and on self care resources are prerequisites for adequate
rehabilitation efforts that are patient-oriented and of high quality. To make
sure that interventions promote or stabilize the quality of life, the
participation of the client is inevitable in all stages of the process of care
planning and coordination. The results of a research project concerning
cooperative quality improvement carried out at the Agnes Karll Institute for
Nursing Research stress these assumptions.
PMID- 9757520
TI - [The future of medical technology assessment in Germany--five proposals for its
development].
AB - How progress in medicine will be financed in the future is an important issue
internationally and in Germany. Medical Technology Assessment is an
interdisciplinary concept that proposes solutions to this issue. This article
deals with health political measures which should be taken to implement Medical
Technology Assessment in the German health care system. Five proposals are
developed: Establishing a coordinating and communication unit for Medical
Technology Assessment. Intensifying the research into efficient health care.
Increasing the use of Medical Technology Assessment in coverage decisions.
Increasing consumer participation in coverage decisions. Establishing a
competitive order for the use of expensive technology.
PMID- 9757521
TI - [Rhinologic aspects in the diagnosis of recurrent epistaxis].
AB - Severe and frequently occurring epistaxis is a common problem in the praxis of
the general practitioner. It may be a symptom of another disease which should be
found. A specific pharmacological history has to be taken. This article tries to
review the most important rhinologic aspects for the general practitioner that
the development of the rhinologic disease works as guidance for the differential
diagnosis of recurrent epistaxis.
PMID- 9757522
TI - [The antiphospholipid syndrome].
AB - Antiphospholipid syndrome (APS) is a thrombophilic disorder, which embraces
almost all specialities. This article includes information about the history,
classification, epidemiology, clinical manifestations and treatment of the APS.
It is the aim of this article to introduce the APS with clinical features of all
medical specialities to show the actuality of the syndrome which is not known
everywhere.
PMID- 9757524
TI - [Treatment guidelines--depression. Recommendations for treatment of depression
from the pharmaceutical commission of the German medical profession].
PMID- 9757523
TI - [Methodological quality of clinical practice guidelines in Germany: results of a
systemic assessment of guidelines presented on the Internet].
AB - Critics claim that most of the German clinical practice guidelines are of poor
quality having produced by informal ad hoc methodologies without a rigorous
approach. This paper reports on the systematic appraisal of 329 guidelines
published online by the Association of the Scientific Medical Societies (AWMF) in
Germany. The results of this study suggest that most of the guidelines presented
in Internet do not meet internationally recognised criteria for quality.
Proposals are offered how to enhance the methodological quality of future
guidelines.
PMID- 9757525
TI - [Quality control in Austrian hospitals--results of evaluation].
AB - The revision of the federal hospital act (Nov. 11, 1993; BGB1 Nr. 801/93) intends
the introduction of an internal quality control as well as comparisons between
different hospitals. For the application fo these constitutional requirements,
the state governments had to develop laws being the basis for the hospital
management to implement quality assurance. To support the introduction of a
systematic quality control, the federal ministry of health published a guideline
for quality assurance which was made available to all hospitals. Now, a
questionnaire in all Austrian hospitals was designed to evaluate the progress and
the specific ways of implementations as well as the possible need for action in
the future.
PMID- 9757526
TI - [Determinants for diagnostic and therapeutic co-operation between general
practitioners].
AB - In the light of new opportunities for structural arrangements in Germany calling
for higher co-operation between physicians in private practice, determinants for
diagnostic and therapeutic co-operation need to be examined. In the present
study, 130 general practitioners were asked in regard to four typical primary
care indication groups whether they prefer to diagnose and treat the patients on
their own or in co-operation with colleagues. This self-assessment was validated
using the data from 2,069 physician-patient contacts: physicians preferring
therapy in co-operation actually referred patients three times more often.
Concerning both gastro-intestinal and rheumatic disorders, physicians'
preferences for diagnostic and therapeutic co-operation are highly correlated
(phi = 0.491 and 0.528 respectively); preferences for diagnostic and therapeutic
co-operation across indications are not as strongly correlated (phi = 0.334 and
0.397 respectively). However, there is no general indication-independent attitude
towards co-operation for individual physicians: Indication and type of services
are two factors which--probably in addition to others--affect co-operation
independently. We confirm earlier conclusions that the detailed analysis of
provider and patient characteristics together with the actual patient management
on a case by case basis is a powerful tool for health services research.
PMID- 9757527
TI - [Regulation of psychotherapists].
PMID- 9757528
TI - [The Marburg Parent-Child Spelling Trainer--follow up studies after 2 years].
AB - The results of a two-year parent-child training program are reported. After one
year of supervised tutoring by one of their parents, the children had only
improved in those spelling areas that had been worked on in the program,
otherwise there was no general improvement in their spelling ability. After the
second year, not only their spelling ability in the specific areas had continued
to increase, but their general spelling ability (spelling test percentile rank)
had also improved. Their self-confidence had increased markedly as well.
Significant predictors of the specific spelling improvement were the specific
spelling ability at the initial measurement and whether or not the mother was
working; significant predictors for the general improvement could not be found.
Supervised tutoring by the parents was shown to be effective for improving
childrens' spelling ability.
PMID- 9757529
TI - [An inventory for assessing the quality of life of children and adolescents--a
pilot study].
AB - Up to now, the quality of life of children and adolescents with psychiatric
disorders has rarely been investigated. Not many suitable instruments are
available. A new one is the "Inventory for the Assessment of the Quality of Live
in Children and Adolescents" presented here. Objectives and underlying conceptual
assumptions are discussed, followed by an explanation of the instrument itself
(questionnaires, rating scales, etc.). Finally, experiences with the application
of the instrument are reported together with initial empirical results from a
clinical sample and a sample of high school students. These indicate that the
instrument usefully assesses clinically relevant information about the quality of
life of the patients. A broader empirical analysis of this method is being
prepared.
PMID- 9757530
TI - [Assessing the quality of life of children and adolescents with psychiatric
disorders--a review].
PMID- 9757531
TI - [Disorder-specific psychotherapy in child and adolescent psychiatry].
PMID- 9757533
TI - [Surgical therapy of the injured spine].
PMID- 9757532
TI - [How can psychodynamic diagnosis in childhood and adolescence be
operationalized?].
AB - Multiaxial diagnostics and classifications in child and adolescent psychiatry
based on ICD-10 generally now have been operationalized. Initial procedures to
operationalize psychodynamically oriented concepts are currently underway. One of
them is the operationalized psychodynamic diagnostics (OPD), which consists of
five axes: illness concepts and treatment predispositions, human relationships,
intrapsychic conflict, psychic structure, and the ICD-10. A team is currently
adapting the adult version of the OPD for use in children and adolescents. Such
an OPD-CA would affiliate with the MAS, a well-established system of
classification. Central methodological and conceptual topics of the OPD-CA are
presented.
PMID- 9757534
TI - [Reduction and positioning of cervical spine injuries].
AB - Prerequisites for successful reduction of cervical spine injuries are an exact
analysis and classification of every lesion. In locked dislocations disc
protrusion should be excluded prior to reduction by MRI or CT-scan. For manual
reduction and closed manipulation by the trauma surgeon we use a halo-ring which
is applied in local anaesthesia and fluoroscopic control. The anatomic position
is maintained by a halo-fixator until surgery. Skeletal traction is used mainly
for locked dislocations and late malalignements. Traction is provided by a halo
ring and weights up to 20 kg. Repeated clinical and neurological examinations are
necessary to rule out overdistraction of the spine or neurologic deterioration.
The weight may be reduced after reduction to 2 kg. For intraoperative positioning
and reduction of cervical spine injuries we designed a special device which is
connected to the halo ring and allows to fix the head and spine in any desired
position. It may be used in prone or supine position of the patient. Operative
reductions are rarely necessary on the cervical spine. Typical indication are
fractures of posterior elements of the spine preventing closed reduction.
Reduction manoeuvers depend on the kind of injury and are mainly composed of
traction and a reversal of the trauma mechanism. The most severe complication is
a neurologic deterioration. Reports in literature about 13 patients having
sustained such a fate are showing the following: In most cases disc material
dislocated in the spinal canal during reduction could be made responsible for the
catastrophic course. Especially at risk are patients with open reduction from a
posterior approach.
PMID- 9757535
TI - [Indications for surgical management of injuries of the cervical spine].
AB - The indication for operative treatment of serious injuries to the cervical spine
is basically determinated by instability and dislocation. Timing of the operation
is based on the neurological deficit. If there is a chance for recovery operative
treatment is urgent. For the upper cervical spine defined indications are
existing for type-2-fractures of the dens and C 2/C 3-instabilities of the
hangman-type with major dislocation. Fractures of C 0 and C 1 are preferably
treated by conservative methods. Only cases with compound injury patterns with a
high degree of ligamentous instability may require dorsal fusion. For serious
injuries of the lower cervical spine operative treatment is needed in most
instances. Conservative treatment is only indicated if functional stability can
be proofed and injuries to the discs and compression to the myelon are ruled out.
PMID- 9757536
TI - [Surgical therapy of dens fracture].
AB - The use of Anderson/D'Alonso or Aebi/Nazarian classification of dens fractures is
the basis for exact selection of therapy. The ventral screw-fixation of Anderson
type-II-Fracture is today the common standard of treatment, especially in the
elderly. The stabilisation of the fracture with maintenance of atlanto-axial
rotation-function, the minimal rate of pseudarthrosis compared with conservative
therapy, the minimal operation trauma and the immediate mobilisation with high
patient comfort are decisive benefits of this method. Reposition of the fracture,
visualisation in two planes and the use of adequate instruments are important
conditions to get optimal operation results. In-vitro-experiments have shown that
there is no difference of stability in one- or two-screw-technique. Flexion
injuries with oblique fracture plane, insufficient stability after anterior screw
fixation and typ-III-fractures are indications for dorsal, atlanto-axial screw
fixation. The conservative treatment(HALO-vest) is recommended only in otherwise
inoperable patients.
PMID- 9757537
TI - [Ventral interbody spondylodesis in injuries of the cervical spine. Indications,
surgical technique and results].
AB - Lower cervical spine injuries with instability of the anterior and/or posterior
column can be treated by anterior interbody fusion and plate fixation. Plates
available for anterior instrumentation of the lower cervical spine can be divided
into locking or non-locking systems with uni- or bicortical screw purchase. Our
biomechanical comparative testing of different screw fixation systems
demonstrates improved stability with the use of bicortical purchase. Clinical
studies, however, have proven high fusion rates without loss of correction and a
low implant related morbidity with the use of unicortical as well of bicortical
plate systems. Correct reduction and intraoperative positioning of the unstable
cervical spine is crucial to avoid implant related complications. Also,
limitations of anterior instrumentation for the treatment of specific lesions of
the lower cervical spine have to be considered, e.g. in complex lesions with
axial instability or in fracture dislocations with ankylosing spondylitis.
Changes or alterations of adjacent segments can be reduced by the use of plates
with correct lengths, contact of uninjured adjacent discs with implants should be
avoided. A comparative analysis of two patient collectives--89 patients (1972
1983) and 102 patients (1987-1994), all of them treated with bicortical plate
fixation--revealed different results in terms of implant failure, operative
reduction and loss of correction. All but one surgical fusions had healed
radiologically. Implant related complications during the first 3 months after the
initial operation were lower in the latter group, only 3 out of 102 patients (3%)
with implant loosening versus 7 our of 89 patients (8%) with implant breakage or
loosening required surgical revision. In all cases technical errors could be
detected. Clinical follow-ups with personal examination was performed in 144
patients: 57 of 72 survivors of series I (79%) after an average time of 11 years
9 months and 87 out of 94 survivors of series II (85%). The radiologic
examination revealed 2 patients with screw breakage in series I, one patient with
an asymptomatic implant loosening in series II. Only one case was observed with a
loss of correction after loosened and early removed hardware. In all other
patients there was no difference of radiologic angles between postoperative X-ray
and follow-up. 16 patients, 12 of series I, 4 of series II, were fused in a
kyphotic position after insufficient preoperative reduction. Radiologic
alterations of adjacent segments, i.e. spondylophyts or "spontaneous" fusions,
were observed in more than 50% of all patients of both series. However,
complaints or persistent pain did not correlate with radiologic findings. Also in
both series there was a high percentage of patients with mild, residual neck pain
in spite of a very good radiologic result. Only in a very few cases the
complaints had to be treated by drugs.
PMID- 9757538
TI - [Thoraco-lumbar spinal injuries--surgical indications and timing].
AB - In thoracolumbar spine injuries, the indication for operative treatment and the
time of operation are defined basically by the injury-pattern and by complicating
neurological deficits. Immediate decompression is crucial in cases with worsening
or secondarily occurring neurological involvements; incomplete paraplegia calls
for undelayed decompression. Since accompanying neurological impairment usually
represents high-grade instability of the spine, decompression includes fusion of
the unstable motion segments. Both stability and shape of the spine determine the
functional and subjective result within certain limits of tolerance. Therefore,
clear indications for operative treatment exist for the following situations: no
reduction possible in a closed manner, conservative fixation unpromising after
closed reduction, restoration of stability uncertain in mainly ligamentous
injuries. In addition, significant kyphotic and/or scoliotic deformities also
require operative correction for satisfying results. An individual evaluation of
both the benefit and the risk of all available therapeutic options is needed for
every single case of only relative indication for operative measures. The
accurate analysis of the injury-pattern determining stability and chances of
healing as well as the knowledge of the efficiency of the planned therapy are
prerequisites for a differentiated indication.
PMID- 9757539
TI - [Dorsal stabilization of fractures of the thoracic and lumbar spine by external
fixator--technique and outcome].
AB - Posterior stabilization by internal fixator is used as a frequent procedure for
the surgical treatment of thoracolumbar spine fractures. The technique of
internal fixator stabilization and its results regarding the correction of spinal
posture and spinal canal clearance are described. By transpedicular spongiosal
filling of the reduced vertebral body, a complete consolidation can be achieved.
Occurring correction losses of the spinal alignment are mainly attributed to the
collapse of intervertebral segments, thereby suggesting insufficient anterior
fusion and support after transpedicular intercorporal cancellous bone grafting.
Spinal canal narrowings can only be cleared partially through posterior approach
and indirect reduction by internal fixator. In abscence of neurological deficits,
residual spinal canal encroachments can be tolerated after surgery, since
remodelling phenomenons occur subsequently. However, symptomatic spinal cord
compression requires a more efficient decompression technique by direct posterior
approach, risking manipulation damage of neural structures. The limited
possibilities of internal fixator technique demand the discerning consideration
of alternative anterior or combined anterior-posterior procedures for the
planning of surgical treatment. For spinal fractures with pronounced destruction
of the anterior column and associated intervertebral disc ruptures, an interbody
fusion by anterior approach should be performed. In case of additional posterior
or transverse instability, a supplemental stabilization by internal fixator is
necessary. For severe spinal canal encroachments at thoracic spine level with
symptomatic or imminent spinal cord compression, the most efficient decompression
by an anterior approach is preferred.
PMID- 9757540
TI - [Laparoscopy-assisted harvesting of free small intestine transplants for
reconstruction of voice and deglutition after total laryngopharyngectomy--an
animal experiment study].
AB - Based on animal trials the presented study results describe a laparoscopic
assisted removal of an extra-long free jejunal graft to reconstruct voice and
swallowing after a total laryngo-pharyngectomy in cases with advanced
malignancies of the larynx including invasion in the upper oesophagus. With a
microvascular anastomosed small bowel segment, we have been able to reconstruct
parts of the pharynx and to create a speaking syphon as devised by Ehrenberger in
an one-stage procedure. The concept of avoidance of an extensive laparotomy may
result in an decreased morbidity of this surgical procedure. Therefore it
represents a challenging single indication of minimally invasive surgery of the
oesophagus. A well established interdisciplinary teamwork is the key for success
in this extensive procedure.
PMID- 9757541
TI - [History of surgical instruments: 7. The first electrosurgical instruments:
galvanic cauterization and electric cutting snare].
AB - In 1854 the surgeon Albrecht Theodor Middeldorpf (1824-1868) published the first
monography on the application of electrical current in surgical operations
("galvanocautery"). By galvanocautery Middeldorpf defined a procedure in which
specially constructed parts of surgical instruments (usually thin platinum wires)
were transformed into glowing heat by means of galvanic current from a zinc
platinum-battery. In this manner it was possible to perform dissection and
destruction of tissue as well as coagulation of vessels for hemostasis. His most
important electrosurgical instruments comprised an electrosurgical knife
("galvanocautery") and the electrical cutting snare ("ligatura candens") for
removal of polypoid tumors. These instruments are the direct ancestors of modern
electrocautery or cautery snare. The glowing platinum wire was later also applied
as a light source of cystoscopes. Thus, galvanocautery enabled development of
endoscopy. Modern diathermy with high-frequent alternating current was introduced
in medicine by the Dermatologist Franz Nagelschmidt from Berlin.
PMID- 9757542
TI - [Puncture, catheterization and drainage. 1].
PMID- 9757543
TI - [Peripheral blood stem cell transplantation as an interdisciplinary challenge-
theory and practice].
AB - High dose chemotherapy with consecutive autologous peripheral blood stem cell
transplantation becomes increasingly important for the treatment of hematological
diseases and solid tumors. A complete remission or at least a prolonged survival
can be achieved for numerous malignant diseases by an intensification of chemo-
and radiotherapy. Therefore, the autologous peripheral blood stem cell
transplantation (PBSCT) represents an elementary precaution to reduce the therapy
associated aplasia by administration of hematopoietic precursor cells. Both, high
dose chemotherapy with consecutive PBSCT demands great clinical experience and
the collection, processing and positive selection of blood stem cells is a
challenge for the Transfusion Medicine. Correct handling and utilization of blood
stem cells for clinical and laboratory purposes (e.g. positive selection) must be
guaranteed, since each restriction of the function of processed blood stem cells
may lead to an insufficient engraftment after PBSCT. Therefore, the clinical
divisions of the University Hospital Munster are planning and practising
peripheral blood stem cell transplantations in cooperation with the Department of
Transfusion Medicine. The collection, processing and quality control are
performed by the Department of Transfusion Medicine in close contact with the
other clinical departments, who subsequently perform high dose chemotherapy and
peripheral blood stem cell transplantations.
PMID- 9757544
TI - [Cervix carcinoma: staging, therapy, after-care. Experiences with magnetic
resonance tomography of cervix carcinoma based on recent literature 1993 to
1997].
AB - The investigation of cervix carcinoma with magnetic resonance tomography (MRT) is
still controversially discussed with regard to its diagnostic value as well as
for planning radiation therapy. The purpose of this article is to present and
discuss papers published between 1993 and 1997 in this field with respect to the
technique used, the contrast media applied and its clinical value. A literature
search using three different databases (Medline, Embase, Cancerlit) identified 39
publications, which were then analysed. Despite the partially suboptimal
presentation of results in these papers MRT proved superior to other imaging
modalities. Due to better demarcation of cervix carcinoma with MRT, it was
possible to calculate tumor value as well as to correctly judge the infiltrative
character. This allows for a more precise treatment and staging of the patient's
prognosis. In the future, MRT might be useful in diagnosing recurrence at
relatively early stage. Unfortunately lymphatic nodes can only be insufficiently
verified using MRT.
PMID- 9757545
TI - [Intracytoplasmic injection (ICSI) of cryopreserved testicular spermatozoa (Cryo
TESE): a retrospective study of the first 250 treatment cycles].
AB - It is reported on the results of 250 treatment cycles in which we carried out
intracytoplasmic injections (ICSI) with frozen and thawed testicular spermatozoa
(cryo-TESE). Up to July 1997 we treated 127 patients, 225 embryo transfers were
performed (90%), and an average of 2.3 preimplantation embryos were transferred.
This resulted in 53 clinical pregnancies, six patients aborted (11.3%). The
pregnancy rate was 21.2% per treatment cycle, 23.5% per embryo transfer, and
41.7% per patient. This so called cumulative pregnancy rate is still about to
rise, because 49 out of the 72 non-pregnant patients are still in our ICSI
program. Twenty-two children are born, 2 twins and 1 triplet. All children are
healthy and without any major malformations. We conclude from these results that
using cryopreserved testicular sperm for ICSI is an effective and successful
approach for the treatment of severe testicular insufficiency. In comparison to
the use of native testicular sperm with the necessity of repetitive testicular
biopsies, cryopreservation is advantageous in many concerns (e.g. logistic,
organisatoric and financial) and is therefore recommended for clinical routine.
PMID- 9757546
TI - [Endometriosis: clinical, histological and morphometric findings before and after
Gn-RH agonist therapy].
AB - After bioptical diagnosis of endometriosis, 81 patients were treated with GnRH
agonists buserelin or leuprolide for six months. Biopsies before and after
treatment were used to test a semiquantitative score-system, regarding atrophy of
glands and stroma cells. Furthermore glandular diameter, circumference and area
of nuclei were examined morphometrically using a microscopic semiautomatical
measuring system. Morphometrical and histological alterations during therapy were
evaluated. Additionally, data suitable for predicting a possible therapeutic
success were described. After therapy 40 patients still showed endometriotic
implants (partial responder) in contrast to 41 cases without foci (total
responder). Therapeutic effect of GnRH-agonists was proved in every respect:
clinical complaints decreased markedly during GnRH-agonists therapy. Both
buserelin and leuprolide treated groups revealed increase of atrophy and
reduction of extension of stroma. Correspondingly morphometrical analysed
parameters such as diameter, circumference and area of glands decreased during
therapy as well as area of cytoplasm and nuclei. Except the diameter of glands,
the leuprolide treated partial responder group (residual foci after GnRH-therapy)
revealed a stronger therapeutic effect than the buserelin treated partial
responder group. Obviously this effect seems to be produced by the stronger
estradiol suppression of leuprolide. Pretherapeutic comparison of measured values
pointed out a minor distinct endometriosis in the total responder group. Success
or failure of therapy seems to depend more on the pretherapeutic degree of
expression of endometriosis. Obviously the kind of applicated GnRH-agonist plays
a minor distinct role. Morphometrical data of endometriotic foci appear to be
appropriate to predict a possible therapeutic success of GnRH-agonist therapy.
But because of many exceptions only a roughly estimated prediction is possible.
PMID- 9757547
TI - [Morphologic findings in fetuses and placentas of late abortion in the 2nd
trimester].
AB - To investigate possible causes of abortion (and intrauterine foetal death) we
reviewed clinical and morphological data of foetuses and placentas
morphologically from 830 spontaneous abortions seen during a 12 years period
(1978-1989) at the Institute of Pathology, University of Leipzig, and the
Pathological Institute of Hoyerswerda. Our review showed that definite and
possible causes of foetal death and abortion could be classified as placental,
foetal maternal, and clinical. Placental changes, which included infection of the
foetal membranes, disturbances of the uteroplacental circulation (abruptio
placentae with bleeding) and placental dysmaturity, were the most important
causes and accounted for 73.8% of the cases. Foetal causes mainly comprised
multiple twin pregnancies and foetal malformations. In 20 cases (2.4%) we found
malformations as a cause of foetal death and consecutive abortion. Overall,
malformations were found in 7.5% of the cases examined. Maternal and obstetric
complications of pregnancy were less frequent. In 16.5% of our cases, the cause
of the abortion or intrauterine death remained obscure. However, since 1989,
genetic analysis and prenatal diagnostic procedures have improved, bringing a
greater knowledge on the spectrum and aetiology of possible developmental
disorders in the foetus. This should reduce the number of unexplained abortions.
PMID- 9757548
TI - [Are there indications for abortion or cesarean section and contraindications for
spontaneous delivery in ophthalmologic diseases? Case report and overview].
AB - Management of labor and indications for abortion in patients with ophthalmologic
diseases are discussed controversially in literature and are often
overemphasized. We present a case of a pregnant woman with bilateral papilledema
due to pseudotumor cerebri, because an abortion was in question. This case lead
us to discuss indications for abortions in patients with pseudotumor cerebri, as
well as indications for abortions or cesarean sections in patients with high
myopia, retinal detachment, retinopathy in EPH-gestosis, uveal melanoma and
diabetic retinopathy. In this article these questions will be discussed.
PMID- 9757549
TI - [Legal questions in telemedicine].
AB - Patient data are protected through data protection law and medical
confidentiality. Telemedicine is a risk factor for medical confidentiality and
data protection. Therefore there is a need for risk reducing strategies.
PMID- 9757550
TI - Binding of lactoferrin to bacterial cells of the Clostridium species and their
agglutination.
AB - Cell agglutination in cell suspensions of 10 strains of Clostridium by
lactoferrin (Lf) was observed by obtaining the ratio of increased absorbance
(RIA) at 450 nm. The RIA values were very different among the species, being
higher in the cell suspensions with bovine Lf (bLf) than in those with human Lf.
The binding ability of bLf to the bacterial cells was also observed by an enzyme
linked ligand-binding assay, using the conjugate of iron-free or iron-saturated
bLf with horseradish peroxidase (HRPO). The binding ability of bLf was very
different among the 10 species, and showed a significant correlation with the
cell agglutination of each strain. bLf formed a complex with the cells of C.
perfringens, did not dissociate in 2 M NaCl or 4 M urea, but did dissociate in 1
M KSCN. These results suggest that the agglutination of cells of the Clostridium
species by bLf is probably caused by the cooperative action of at least
electrostatic and hydrophobic interactions between bLf and certain components of
the cell surface.
PMID- 9757551
TI - Binding characteristics of bovine lactoferrin to the cell surface of Clostridium
species and identification of the lactoferrin-binding protein.
AB - The binding characteristics of bovine lactoferrin (bLf) to cells of the
Clostridium species were observed by using a horseradish peroxidase-bLf
conjugate. A bLf-binding protein (BP) having a relative molecular mass of about
33 kDa was confirmed in the surface layer components from 7 strains of the
Clostridium species. The binding of the conjugate to bLf-BP or C. perfringens was
strongly blocked by intact Lfs, lysine or arginine residues modified bLf, and
deglycosylated bLf, but was not by other milk proteins or by the constituent
sugars of glycan. Bacterial growth was inhibited by bLf, but was slightly
inhibited by lysine residues modified bLf or deglycosylated bLf. Lactoferricin B
did not block the binding of the conjugate, but strongly inhibited the bacterial
growth. This suggests that the lysine or arginine residues and glycan of bLf
hardly participated in binding bLf to the bacterial cells, but that the amino
acid residues and glycan played an important role in inhibiting the growth of
bacteria.
PMID- 9757553
TI - Novel histamine measurement by HPLC analysis used to assay histidine
decarboxylase inhibitory activity of shoyuflavones from soy sauce.
AB - An easy and highly sensitive method for measuring histamine by HPLC analysis
coupled with precolumn derivatization was established. The amino group of
histamine was completely colorimetrically labelled with 4-N,N-dimethylamino
azobenzene-4'-isothiocyanate (DABITC) in the presence of sodium bicarbonate at 90
degrees C for 5 min. The derivative was sensitively and easily analyzed by HPLC
on a Cosmosil 5SL column using CHCl3/N,N-dimethylformamide/H2O (210:90:4)
containing 0.4% acetic acid. Using the established method, histidine
decarboxylase (HDC) inhibitory activities of three tartaric acid isoflavone
derivatives, named shoyuflavones, isolated from soy sauce were examined in vitro
by measuring the histamine produced by HDC. They showed intense inhibition of the
activities of HDC from both mouse mastocytoma P-815 cells and Clostridium
perfringens.
PMID- 9757552
TI - Proanthocyanidins from barley bran potentiate retinoic acid-induced granulocytic
and sodium butyrate-induced monocytic differentiation of HL60 cells.
AB - Polyphenol extract from barley bran (BPE) induced nitro blue tetrazolium (NBT)
reducing activity and alpha-naphthyl butyrate esterase activity in HL60 human
myeloid leukemia cells. Because BPE induced the biochemical markers of HL60 cell
differentiation, we investigated the effects of proanthocyanidins isolated from
BPE on the HL60 cell differentiation of HL60 cells. Prodelphinidin B-3, T1, T2,
and T3 induced 26-40% NBT-positive cells and 22-32% alpha-naphthyl butyrate
esterase-positive cells. Proanthocyanidins potentiated retinoic acid (all-trans
retinoic acid)-induced granulocytic and sodium butyrate-induced monocytic
differentiation in HL60 cells.
PMID- 9757554
TI - Structure-function relationship of T-2 toxin and its metabolites in inducing
thymic apoptosis in vivo in mice.
AB - Recently we found that a single administration of T-2 toxin (T-2), a
trichothecene mycotoxin, into mice induced DNA fragmentation, a biochemical
hallmark of apoptosis, in the thymus. In this study, we investigated the
effective chemical structure(s) of T-2-derived metabolites capable of inducing
thymic apoptosis in vivo in mice. Metabolic conversion of T-2 to 3'-hydroxy-T-2
toxin (3'-OH-T-2) did not diminish the apoptosis-inducing activity, since
essentially the same level of fragmented DNA was detected in the thymus taken
from mice injected with either T-2 or 3'-OH-T-2. In contrast, hydrolysis of T-2
and 3'-OH-T-2 at the carbon-4 (C-4) position to HT-2 toxin (HT-2) and 3'-hydroxy
HT-2 toxin (3'-OH-HT-2), respectively, greatly decreased the level of DNA
fragmentation. Similarly, hydrolysis of T-2 at the carbon-8 (C-8) position to
neosolaniol strongly diminished its ability to induce DNA fragmentation. T-2
tetraol, having no ester groups, was unable to induce apoptosis. Based on the
data presented in this study, we concluded that both the acetyl group at the C-4
position and the isovaleryl or 3'-hydroxyisovaleryl group at the C-8 position of
the T-2 molecule are important for inducing cell death through apoptosis in the
thymus.
PMID- 9757555
TI - Lipoxygenase-1 from soybean seed inhibiting the activity of pancreatic lipase.
AB - There are some similar characteristics in protein nature between the lipase
inhibitor from soybean seed and soybean lipoxygenase-1 (LOX-1). Thus, the
inhibiting protein for pancreatic lipase was prepared from defatted soybean meal
by the procedure for the isolation of LOX-1 [Axelrod et al., Methods in
Enzymology, 71, 441-451 (1981)]. The LOX-1 from soybean seed dose-dependently
inhibited the release of fatty acid from a soybean oil emulsion, and the
concentration of LOX-1 to cause half inhibition of the lipase activity was 3.2 x
10(-7) M. The LOX-1 obtained from E. coli transfected with a plasmid carrying the
soybean LOX-1 gene also inhibited the lipase activity. However, the lipase
inhibiting activity by the LOX-1 was not affected by the presence of
nordihydroguaiaretic acid, an inhibitor for LOX, in the reaction mixture. These
results show that the soybean LOX-1 inhibits lipase activity regardless of its
lipoxygenase activity.
PMID- 9757556
TI - Effect of indigestible oligosaccharides on the hepatotoxic action of D
galactosamine in rats.
AB - The effects of dietary oligosaccharides on the hepatotoxic action of D
galactosamine (GalN) were investigated in this study. Male Wistar rats fed with
20% casein diets containing 10% oligosaccharide or D-galactose (Gal) for 2 weeks
were injected with GalN (1,900 mg/kg of body weight), and the plasma aspartate
aminotransferase (AST) and alanine aminotransferase (ALT) activities and the
hepatic glycogen concentration were examined 20 hours after the injection. The
plasma AST and ALT activities in experiment 1 for the Gal + neomycin (NEO) group
were significantly lower than those for the control (C), NEO, raffinose (RAF) +
NEO and galacto-oligosaccharide (GA-LO) + NEO groups. In experiment 2, these
activities were significantly lower in the Gal, Gal + NEO and RAF groups than in
the RAF + NEO group when the groups were treated with GalN. On the other hand, in
respect of the hepatic glycogen concentration in experiment 1, that of the Gal +
NEO group was higher than that of the C, NEO, RAF + NEO or GALO + NEO groups. In
experiment 2, this parameter was significantly higher in the Gal, Gal + NEO and
RAF groups than in the RAF + NEO group after the GalN treatment. As a result, it
is suggested that the GalN-hepatitis-suppressive effects of indigestible
oligosaccharides such as RAF or GALO is mediated by the action of intestinal
bacteria.
PMID- 9757557
TI - Construction of a BAC library of the rice blast fungus Magnaporthe grisea and
finding specific genome regions in which its transposons tend to cluster.
AB - We have constructed a BAC library of the rice blast fungus Magnaporthe grisea
consisting of 5760 clones. The insert size ranged from 35 to 175 kbp, with an
average of 120 kbp. The library is about 18 genomes equivalent, therefore
covering more than 99.999% of the genome. This library is the first to be
constructed using a rice pathogenic wild type isolate. Improved high molecular
weight DNA size fractionating helped to construct the library with high
efficiency. Total library clones were arranged onto two nylon membranes for
efficient screening. Test hybridization with a single-copy RFLP marker showed ten
positive clones, of which restriction patterns indicated no chimerality or
deletions. As a model case of application of this library, the distribution of
the well-studied fungal retrotransposons MGSR1, MGR583, and MAGGY and DNA
transposons MGR586 and Pot2 was analyzed. Of all the BAC clones, 10%, 13%, 18%,
12%, and 23% contained MGSR1, MGR583, MAGGY, MGR586 and Pot2, respectively. The
percentage of clones possessing more than five kinds of transposons was 1.4%, 215
times greater than the expected number. The results show that these transposons
were distributed in clusters in the M. grisea genome.
PMID- 9757558
TI - Production of a mixture of antimicrobial organic acids from lactose by co-culture
of Bifidobacterium longum and Propionibacterium freudenreichii.
AB - The antimicrobial activities of standard solutions of three organic acids
(lactic, acetic, and propionic acids) were compared using Micrococcus luteus,
Pseudomonas sp. and Staphylococcus aureus as test microorganisms. At the same
concentrations of the undissociated form, the antimicrobial activities of acetic
and propionic acids were higher than that of lactic acid, irrespective of test
microorganisms. In a single cultivation of Bifidobacterium longum, a mixture of
lactic (17 g/l) and acetic (20 g/l) acids was produced from 50 g/l lactose and
its antimicrobial activities against M. luteus, Pseudomonas sp., and S. aureus
correspond to that of 32, 19, and 25 g/l of acetic acid, respectively. To
increase the total antimicrobial activity, a co-culture of B. longum and
Propionibacterium freudenreichii, in which lactic acid produced once from lactose
by B. longum was converted to acetic and propionic acids by P. freudenreichii,
was done using TPY medium containing commercially available peptones as a
nitrogen source. By the sequential conversion of lactose using the two
microorganisms, the culture supernatant containing a mixture of acetic (27 g/l)
and propionic (13 g/l) acids without lactic acid was produced. The antimicrobial
activities of the mixture against M. luteus, Pseudomonas sp., and S. aureus were
35, 30, and 26 g/l as a concentration of acetic acid, respectively, higher than
that obtained in the cultivation of B. longum alone. When the medium containing
an enzymatic hydrolyzate of whey proteins with a protease was used in the co
culture of B. longum and P. freudenreichii, the culture supernatant containing
the mixture of organic acids was also obtained in the same manner as the co
culture using TPY medium and the activities were 43, 29, and 29 g/l as a
concentration of acetic acid for M. luteus, Pseudomonas sp. and S. aureus,
respectively.
PMID- 9757559
TI - Purification and characterization of recombinant human granulocyte colony
stimulating factor (rhG-CSF) derivatives: KW-2228 and other derivatives.
AB - Various derivatives of recombinant human granulocyte colony-stimulating factor
(rhG-CSF) have been overproduced in Escherichia coli with the strong, inducible
trp promoter. A derivative designated as KW-2228 in which the amino acids were
replaced at five positions showed more potent granulopoietic activity and
stability than those of wild-type both in vitro and in vivo. The purification
involved a sequential renaturation process and three-step chromatography.
Refolding succeeded in very high yield using a urea system. The purity of KW-2228
was greater than 99% as measured by SDS-PAGE and HPLC analysis. According to
circular dichroism and nuclear magnetic resonance spectroscopy, rhG-CSF and KW
2228 have very similar conformations. This suggests that the substitution of five
amino acids does not appreciably change the conformation of hG-CSF. KW-2228
([Ala1, Thr3, Tyr4, Arg5, and Ser17]-hG-CSF) and derivative A ([Ala1, Thr3, Tyr4,
Arg5]-hG-CSF) are easily crystallized and they show similar in vitro activity. On
the other hand, neither rhG-CSF nor derivative B ([Ser17]-hG-CSF) are
crystallized under the same conditions. Thus, the four amino acid substitution
(Ala1, Thr3, Tyr4, Arg5) of the N-terminal sequence may facilitate
crystallization. The change of Cys17 to Ser may not influence the stability and
activity of hG-CSF.
PMID- 9757560
TI - Effects of polyphenol substances derived from Theobroma cacao on gastric mucosal
lesion induced by ethanol.
AB - The antiulcer activity of cacao liquor water-soluble crude polyphenols (CWSP) was
examined. CWSP, alpha-tocopherol, sucralfate (500 mg/kg), and cimetidine (250
mg/kg) were orally administered to male SD rats 30 minutes before ethanol
treatment. 5 ml/kg of ethanol given intragastrically caused lesions in mucosa of
the glandular stomach. CWSP caused a reduction of such hemorrhagic lesions as
well as cimetidine and sucralfate which are typical antiulcer drugs, but alpha
tocopherol was less effective. Thiobarbituric acid reactive substances in gastric
mucosa significantly increased with ethanol administration. CWSP treatment
significantly reduced this change. The administration of ethanol extensively
increased myeloperoxidase (MPO) but not xanthine oxidase (XOD) activity. CWSP
reduced the activities of both enzymes; they were considered the main sources of
oxygen radicals. According to an in vitro study, CWSP directly reducted XOD but
not MPO. These results suggest that the antiulcer mechanism of CWSP was not only
radical scavenging but also modulation of leukocyte function.
PMID- 9757561
TI - Thermostable beta-galactosidase from an extreme thermophile, Thermus sp. A4:
enzyme purification and characterization, and gene cloning and sequencing.
AB - We purified and characterized a thermophilic beta-galactosidase from Thermus sp.
A4 isolated from the Atagawa hot spring (Shizuoka, Japan). The enzyme was
monomeric, and its molecular mass was estimated to be 75 kDa by SDS
polyacrylamide gel electrophoresis. The enzyme was extremely thermostable and
retained its full activity after incubation at 70 degrees C for 20 h. The Km
observed were 5.9 mM for ortho-nitrophenyl beta-D-galactopyranoside and 19 mM for
lactose. We cloned and analyzed the complete sequence of the gene encoding this
enzyme. It was found to consist of 645 amino acid residues. We propose that this
enzyme and seven other unclassified beta-galactosidases are new members of family
42 of the glycosyl hydrolases.
PMID- 9757562
TI - Molecular properties and activity of a carboxyl-terminal truncated form of
xylanase 3 from Aeromonas caviae W-61.
AB - Aeromonas caviae W-61 produces five species of xylanases, xylanases 1, 2, 3, 4,
and 5 [Nguyen, V.D. et al., Biosci. Biotechnol. Biochem., 56, 1708-1712 (1993)
and Appl. Environ. Microbiol., 57, 445-449 (1991)]. While preserving a purified
xylanase 3 preparation from A. caviae in solution at 4 degrees C, the xylanase 3
was found to be proteolyzed to give a truncated form with a smaller molecular
mass than that of the intact one. It appears likely that the truncated form of
xylanase 3 was produced in this particular purification experiment by the action
of a contaminating protease. We isolated the truncated form of xylanase 3
(Xyn3tr), of which the C-terminal 102-residue segment is missing. By the chemical
analysis of the N- and C-terminal amino acid residues of Xyn3tr and the DNA
sequencing analysis of the xylanase 3 gene (xyn3), the N-terminal 398th proline
residue of xylanase 3 was found to be the C-terminus of Xyn3tr. Xyn3tr had the
activity to form xylotriose (X3), xylotetraose (X4), xylopentaose (X5), and
xylohexaose (X6) as main final products from oat spelt xylan. In contrast, intact
xylanase 3 released X6 and higher xylo-oligosaccharides as main products.
Xylanase 3 hydrolysed X4 through X6. However, Xyn3tr had no activity towards X4
and X5. The recombinant Xyn3tr and recombinant xylanase 3 (XYN3) were purified
homogeneously from the periplasmic space of E. coli harboring the plasmids pXYN3
and pXYN3tr, which include xyn3 and xyn3tr genes, respectively, and their
enzymatic activities were measured. The cleavage patterns of oat spelt and xylo
oligosaccharides by XYN3tr were identical with that by intact Xyn3tr. Thus, we
conclude that the C-terminal region comprising a 102-residue segment in xylanase
3 is involved in governing the molecular size of xylo-oligosaccharides cleaved
from beta-1,4-xylan by the enzyme and in the hydrolytic activity towards X4 and
X5.
PMID- 9757563
TI - Synthesis and biological activities of (-)-6-n-octyl-indolactam-V, a new potent
analogue of the tumor promoter (-)-indolactam-V.
AB - (-)-Indolactam-V (1) without a hydrophobic chain at positions 6 and 7 of the
indole ring is a weak tumor promoter compared with teleocidin Bs. To investigate
the effects of the hydrophobic substituent at position 6 of teleocidin Bs, we
synthesized (-)-6-n-octyl-indolactam-V (2) by a palladium-catalyzed coupling
reaction from (-)-6-bromo-indolactam-V (7) which had been obtained by microbial
conversion with Streptoverticillium blastmyceticum NA34-17 as the key step. (-)-7
n-Octyl-indolactam-V (3) with potent biological activities comparable to those of
teleocidin Bs was similarly synthesized from (-)-7-bromo-indolactam-V as a
positive control. Compound 2 showed similar biological activities to those of 3,
indicating that the effect of the hydrophobic substituent at position 6 of 1 was
identical to that at position 7.
PMID- 9757564
TI - Characterization of a mutant of Lactococcus lactis with reduced membrane-bound
ATPase activity under acidic conditions.
AB - A mutant of Lactococcus lactis subsp. lactis C2 with reduced membrane-bound
ATPase activity was characterized to clarify its acid sensitivity. The
cytoplasmic pH of the mutant was measured in reference to the parental strain
under various pH conditions. At low pH, the mutant could not maintain its
cytoplasmic pH near neutral, and lost its viability faster than the parental
strain. The ATPase activities of cells cultured under neutral and acidic
conditions using pH-controlled jar fermentors were measured. The relative ATPase
activity of the mutant at pH 7.0 was 42% of the parental strain. At pH 4.5, the
parental strain showed an ATPase activity 2.8-fold higher than that at pH 7.0
while the level of increase in the mutant was only 1.6. Northern and Western blot
analyses found that at pH 7.0 the transcriptional level and the amount of F1 beta
subunit were similar in both strains, suggesting that the mutant has a defective
ATPase structural gene. On the other hand, at pH 4.5 the transcriptional level
and the amount of F1 beta subunit were found to be significantly higher in both
strains than those at pH 7.0. From these results, it was suggested that the
mutant has a normal regulation system for ATPase gene expression. It was
concluded that the mutant is acid sensitive due to its inability to extrude
protons out of the cell with defective ATPase under acidic conditions.
PMID- 9757565
TI - Changes in the level of sialic acid in plasma, brain and liver of inherently
scorbutic rats during vitamin C and E deficiencies.
AB - The plasma level of sialic acid (NeuAc) in inherently scorbutic [Osteogenic
Disorder Shionogi (ODS)] rats was increased by 21 days of vitamin C deficiency.
The brain content of NeuAc was decreased by deficiencies of these vitamins. The
NeuAc level in the liver was not affected significantly by these deficiencies.
PMID- 9757566
TI - Use of Escherichia coli polyphosphate kinase for oligosaccharide synthesis.
AB - The Escherichia coli polyphosphate kinase (PPK) has been known to catalyze the
reversible transfer of phosphate molecules between ATP and polyphosphate
(poly(P)). It has also been found that the PPK catalyzes the kination of not only
ADP but also other nucleoside diphosphates (NDPs) using poly(P) as a phosphate
donor, yielding nucleotide triphosphates (NTPs). We used the PPK and poly(P) in
place of pyruvate kinase and phosphoenol pyruvate for NTP regeneration followed
by synthesis of sugar nucleotides in a cyclic synthesis system for
oligosaccharides. It was confirmed that the PPK efficiently catalyzed the UTP
regeneration in the cyclic system of N-acetyllactosamine synthesis. This novel
activity of PPK enables us to perform the practical synthesis of
oligosaccharides.
PMID- 9757567
TI - Whole sequence of spoIIIE-like, sporulation-inhibitory, and transfer gene (spi)
in a conjugative plasmid, pSA1.1, of Streptomyces azureus and detection of spi
like gene in the actinomycete chromosome.
AB - The nucleotide sequence of spoIIIE-like and the sporulation-inhibitory and
transfer gene (spi) in a conjugative plasmid, pSA1.1, of Streptomyces azureus
were examined to detect the promoter region. Using Southern blotting and a spi
fragment as probe, spi-like genes were detected in chromosomes of the host and
other actinomycetes. These results suggest that there is a spi- and spoIIIE-like
gene in chromosomes of some actinomycetes.
PMID- 9757568
TI - Characterization of ribonucleases from culture medium of Lentinus edodes.
AB - Lentinus edodes (shiitake) cultivated in potato dextrose medium produced five
RNases in the culture filtrate. The two major RNases (RNase Le37 and RNase Le45)
were highly purified and their molecular masses, base specificities, N-terminal
amino acid sequences, and amino acid compositions were analyzed and compared to
RNase Le2 isolated from the fruit bodies of the same mushroom. RNase Le37 and
RNase Le45 are base non-specific and adenylic acid preferential RNases like RNase
Le2 and their N-terminal sequences are very similar to RNase Le2, but they are
glycoproteins and their amino acid compositions are significantly different from
that of RNase Le2. In addition to these enzymes, a guanylic acid-specific RNase
with a molecular mass 13 kDa was partially purified. Since RNase Le2, which has
very similar N-terminal sequence to RNase Le37 and RNase Le45, was not excreted
from the mycelia, the analysis of the structures of these two excreted RNase may
shade a light on the mechanism of excretion of RNases in this organism.
PMID- 9757570
TI - Expression of Aspergillus aculeatus No. F-50 cellobiohydrolase I (cbhI) and beta
glucosidase 1 (bgl1) genes by Saccharomyces cerevisiae.
AB - A cellobiohydrolase I (cbhI) and a beta-glucosidase 1 (bgl1) gene of Aspergillus
aculeatus were expressed in Saccharomyces cerevisiae. The transformed cells
secreted the enzymes efficiently in an active form. The recombinant CBHI gave two
bands of different molecular mass (110 and 90 kDa) and the recombinant BGL1 gave
one band (180 kDa) by SDS-PAGE. The recombinant CBHI and BGL1 had the same
enzymatical properties as the native enzyme except for the specific activity
toward cellulosic substrates. By the combination of three different types of
cellulases, FI-CMCase, CBHI, and BGL1, we could hydrolyze Avicel up to 59% under
our experimental conditions.
PMID- 9757569
TI - Effects of glycosylation of the residue at position 14 in ovine angiotensinogen
on the human renin reaction.
AB - A mutant angiotensinogen, S14N, in which Ser14 of ovine angiotensinogen was
replaced by Asn to form a N-glycosylation site, was produced in CHO cells. The
molecular weight was about 3,000 larger than that of wild-type ovine
angiotensinogen, indicating that S14N angiotensinogen was glycosylated at Asn14.
In the reaction with human renin, the km of mutant angiotensinogen was 3 times
increased, but the Vmax was not affected by the mutation.
PMID- 9757571
TI - Biological and structural properties of cyclic peptides derived from the alpha
amylase inhibitor tendamistat.
AB - Six cyclic peptides with 5, 7, 9, 11, 13, and 15 amino acids, with the inhibitory
sequence of the alpha-amylase inhibitor tendamistat, were synthesized. The 11
residue peptide inhibited porcine pancreatic alpha-amylase most potently (K1 0.29
+/- 0.09 microM). For the 11-residue peptide, the circular dichroism study
suggested a preliminary relationship between its inhibitory activity and
structural property.
PMID- 9757572
TI - Phospholipid deacylating activities included in yeast.
AB - Yeast had been known to contain only one kind of phospholipid deacylating enzyme
with an optimal pH in the acidic range. However, among 8 genera and 25 strains, 7
genera and 13 strains had phospholipid deacylating activity at pH 8.0, when
screening of enzyme activity was done with micellar and liposomal substrates. The
enzymatic properties of phospholipid deacylating enzyme existing in yeast was not
related to genetic identity based on 18S rRNA gene sequence. The results suggest
that yeast contains enzymes showing a variety of properties depending on the
species of yeast, and further studies on this enzyme with more varieties of
yeasts are necessary for understanding the physiological roles of the enzyme in
yeast.
PMID- 9757573
TI - Nucleotide sequence of the gene encoding the precursor protein of pepstatin
insensitive acid protease B, scytalidopepsin B, from Scytalidium lignicolum.
AB - A chromosomal DNA of Scytalidium lignicolum was digested with Sau3AI. The digest
was self-ligated and amplified by inverse PCR procedure using primers designed
based on the nucleotide sequences of up- and down-stream regions of an intron
present in the scytalidopepsin B gene. Analysis of the nucleotide sequence of PCR
product (700 bp) showed that the enzyme is synthesized as a precursor protein
consisting of the prepro- and mature enzyme regions. The deduced amino acid
sequence was highly similar to those of aspergillopepsin A and recently reported
endothiapepsins B and C, but quite different from those of pepstatin-insensitive
bacterial acid proteases and the pepstatin-sensitive aspartic protease family.
PMID- 9757574
TI - Mapping of human DNA-binding nuclear protein (NP220) to chromosome band 2p13.1
p13.2 and its relation to matrin 3.
AB - Human NP220 (hNP220) is a novel DNA-binding nuclear protein, which has an
arginine/serine-rich motif and polypyrimidine tract-binding motif, and NP220s and
matrin 3 are thought to form a novel family of nuclear proteins. We have
determined a chromosomal localization of the cDNA encoding human NP220 to 2p13.1
p13.2 by using fluorescence in situ hybridization. Human matrin 3 cDNA was mapped
to chromosomes 1p13.1-p21.1 and 5q31.3, demonstrating that these novel nuclear
proteins with similar functions are on different chromosomes.
PMID- 9757575
TI - Evaluation of the macrocyclic antibiotic avoparcin as a new chiral selector for
HPLC.
AB - Avoparcin is a macrocyclic glycopeptide antibiotic structurally related to
vancomycin, teicoplanin, and ristocetin A. When attached to 5-microns spherical
silica gel, the avoparcin proved to be an effective chiral stationary phase (CSP)
that could be used in the reversed-phase, normal-phase, and polar-organic modes.
The avoparcin CSP was complimentary to the other macrocyclic glycopeptide CSPs in
that it could resolve some racemates that the others could not, and vice versa.
Some important compounds resolved on the avoparcin CSP include verapamil,
thyroxine, mephenytoin, and 2-imidazolidone-4-carboxylic acid. The use of this
CSP and the optimization of separations on it are discussed. Avoparcin appears to
be a useful addition to this family of CSPs.
PMID- 9757576
TI - Near-UV, circular dichroism, and fluorescence spectra of a rigid rodlike helical
polysilane bearing trietheral moiety in ethanol/water.
AB - An optically active, rigid rodlike helical polysilane with 6, 9, 12
trioxatetradecyl and (S)-2-methylbutyl substituents (1) was newly obtained as a
very high molecular weight polymer of several million. Due to the presence of
trietheral substituent, 1 was readily soluble in a polar solvent such as ethanol
and a mixture of ethanol and water, but was insoluble in pure water. Polysilane 1
in pure ethanol at room temperature exhibited an intense and narrow ultraviolet
(UV) and circular dichroism (CD) absorptions at 323 nm, associated with an almost
mirror imaged fluorescence (FL) at 328 nm, that are characteristics of rigid
rodlike, single-screw-sense helical polysilanes reported previously. When
solution temperature was changed from 60 degrees C to -104 degrees C, a global
shape of 1 expanded associated with an increase of segment length, whereas a
screw pitch tended to be wound tightly. On the other hand, as a solvent polarity
became poor, a global shape of 1 shrunk associated with an decrease of segment
length and formed a chiral motif with an M-helicity between two helical segments
with a kink. At a ratio of 50% of ethanol/water of 50:50 (v/v), 1 became
insoluble and formed aggregates.
PMID- 9757577
TI - On the effects of noncontingent delivery of differing magnitudes of
reinforcement.
AB - We conducted a parametric analysis of response suppression associated with
different magnitudes of noncontingent reinforcement (NCR). Participants were 5
adults with severe or profound mental retardation who engaged in a manual
response that was reinforced on variable-ratio schedules during baseline.
Participants were then exposed to NCR via multielement and reversal designs. The
fixed-time schedules were kept constant while the magnitude of the reinforcing
stimulus was varied across three levels (low, medium, and high). Results showed
that high-magnitude NCR schedules produced large and consistent reductions in
response rates, medium-magnitude schedules produced less consistent and smaller
reductions, and low-magnitude schedules produced little or no effect on
responding. These results suggest that (a) NCR affects responding by altering an
establishing operation (i.e., attenuating a deprivation state) rather than
through extinction, and (b) magnitude of reinforcement is an important variable
in determining the effectiveness of NCR.
PMID- 9757578
TI - Teaching multiplication facts to students with learning disabilities.
AB - Multiple baseline designs were used to examine the effects of an instructional
package on accuracy of performance in solving multiplication facts by 3 students
with learning disabilities. The instructional package included the following
components: (a) a modified instructional sequence in which multiplication facts
were grouped into the zeros, ones, doubles, fives, and nines categories, and
those remaining; (b) identification of the category in which each fact belonged;
(c) mnemonic strategies associated with solving facts in each category; and (d)
steps to be completed for solving facts in each category. Results indicated that
the instructional package produced substantial and immediate effects. After
receiving instruction, a participant's accuracy was often 100%, and this was
maintained throughout the evaluation even as other strategies were introduced.
Comparable results occurred across students, demonstrating replication of the
effects of the instructional package.
PMID- 9757579
TI - Functional analysis and treatment of destructive behavior maintained by
termination of "don't" (and symmetrical "do") requests.
AB - We used descriptive assessment information to generate hypotheses regarding the
function of destructive behavior for 2 individuals who displayed near-zero rates
of problem behavior during an experimental functional analysis using methods
similar to Iwata, Dorsey, Slifer, Bauman, and Richman (1982/1994). The
descriptive data suggested that destructive behavior occurred primarily when
caregivers issued requests to the participants that interfered with ongoing high
probability (and presumably highly preferred) behaviors (i.e., a "don't" or a
symmetrical "do" request). Subsequent experimental analyses showed that
destructive behavior was maintained by contingent termination of "don't" and
symmetrical "do" requests but not by termination of topographically similar "do"
requests. These results suggested that destructive behavior may have been
maintained by positive reinforcement (i.e., termination of the "don't" request
allowed the individual to return to a highly preferred activity). Finally, a
treatment (functional communication training plus extinction) developed on the
basis of these analyses reduced destructive behavior to near-zero levels.
PMID- 9757580
TI - Effects of differential reinforcement on the generalization of a replacement mand
in three children with severe language delays.
AB - We investigated variables that may influence the generalization of a replacement
mand in 3 young children with severe language delays. A multiple baseline design
consisting of one stimulus class of manding opportunities that we arbitrarily
divided into three categories (i.e., food, toys, and events) was used for each
child. During baseline probes, all children manded mainly by reaching, grabbing,
or leading. We then taught each child a replacement mand using a single member of
the stimulus class. Acquisition of the replacement mand occurred under highly
restricted conditions in a setting that was completely isolated from the
generalization settings. Postacquisition probes revealed almost exclusive use of
old manding forms. Subsequently, extinction of the old forms and reinforcement of
the replacement mand were introduced in a sequential fashion. Two children
manifested a substantial increase, and 1 child displayed a moderate increase in
the occurrence of the replacement mand (i.e., generalization occurred). These
results suggest that a differential reinforcement procedure can alter the
probability of the occurrence of response class members across a variety of
stimulus conditions.
PMID- 9757581
TI - Utilizing increased response effort to reduce chronic hand mouthing.
AB - The effects of increased response effort on levels of hand mouthing, leisure
engagement, and adaptive elbow flexion were investigated with 2 individuals who
had been diagnosed with profound disabilities. Arm restraints designed to alter
the amount of physical effort necessary to engage in hand mouthing were used.
Results indicated that the treatment strategy reduced levels of hand mouthing but
produced only small to moderate reductions in levels of leisure engagement and
adaptive elbow flexion. At follow-up, the effects of increased response effort on
hand mouthing and leisure engagement were maintained for both participants;
however, the restraints were associated with substantial reductions in adaptive
elbow flexion for 1 participant.
PMID- 9757582
TI - Teaching elementary students with developmental disabilities to recruit teacher
attention in a general education classroom: effects on teacher praise and
academic productivity.
AB - Four fourth graders with developmental disabilities were trained to recruit
teacher attention while they worked on spelling assignments in a general
education classroom. The students were taught to show their work to the teacher
two to three times per session and to make statements such as, "How am I doing?"
or "Look, I'm all finished!" Training was conducted in the special education
classroom and consisted of modeling, role playing, error correction, and praise.
A multiple baseline across students design showed that recruitment training
increased (a) the frequency of students' recruiting, (b) the frequency of teacher
praise received by the students, (c) the percentage of worksheet items completed,
and (d) the accuracy with which the students completed the spelling assignments.
PMID- 9757584
TI - Brief functional analysis and treatment of a vocal tic.
AB - This study sought to extend functional methodology to the assessment and
treatment of habits. After a descriptive assessment indicated that coughing
occurred while eating, a brief functional analysis suggested that social
attention was the maintaining variable. Results demonstrated that treatment,
derived from the assessment and analysis data, rapidly eliminated the cough. We
discuss the appropriateness of using functional analysis procedures for deriving
treatments for habits in a clinical setting.
PMID- 9757583
TI - Applying behavior analysis to clinical problems: review and analysis of habit
reversal.
AB - This article provides a review and analysis of habit reversal, a multicomponent
procedure developed by Azrin and Nunn (1973, 1974) for the treatment of nervous
habits, tics, and stuttering. The article starts with a discussion of the
behaviors treated with habit reversal, behavioral covariation among habits, and
functional analysis and assessment of habits. Research on habit reversal and
simplified versions of the procedure is then described. Next the article
discusses the limitations of habit reversal and the evidence for its generality.
The article concludes with an analysis of the behavioral processes involved in
habit reversal and suggestions for future research.
PMID- 9757585
TI - Functional analysis and extinction of different behavior problems exhibited by
the same individual.
AB - Specific extinction procedures were matched to the function of two target
behaviors displayed by the same individual, with results indicating that the
matched extinction procedure suppressed the behavior for which it was designed.
One of the target behaviors was exposed to an irrelevant extinction procedure,
which produced no beneficial effects. These results support previous research
indicating the need to match extinction procedures to the function of problem
behavior.
PMID- 9757586
TI - Assessment of stimulus generalization gradients in the treatment of self
injurious behavior.
AB - Descriptive and experimental analyses suggested that the self-injurious behavior
(SIB) of a 10-year-old girl with severe mental retardation was maintained by
attention. Additional analyses identified physical contact as the type of
attention maintaining SIB; therefore, we hypothesized that physical proximity of
an adult was a discriminative stimulus for SIB. Based on these findings, we
systematically varied the distance between the participant and a therapist to
assess stimulus generalization. Results showed that rates of SIB varied relative
to the distance between the participant and therapist; the highest percentage of
SIB occurred with the therapist positioned less than 0.5 m from the participant.
Treatment consisted of placing the therapist at a specified distance (9.0 m) from
the participant (during low-attention situations), noncontingent reinforcement,
and extinction.
PMID- 9757587
TI - The use of an enhanced simplified habit-reversal procedure to reduce disruptive
outbursts during athletic performance.
AB - An enhanced simplified habit-reversal procedure was used with a 14-year old boy
who presented with a long history of disruptive, angry outbursts during tennis
matches. Initial treatment involved simplified habit-reversal procedures
delivered in a multiple baseline design across settings. Modest results led to
additional supporting contingencies, including response costs. Results showed
elimination of disruptive outbursts during both nontournament and tournament
matches and highlight the importance of adding additional supporting
contingencies to simplified habit reversal for some self-control problems.
PMID- 9757588
TI - Reductions in self-injury produced by transcutaneous electrical nerve
stimulation.
AB - Transcutaneous electrical nerve stimulation is used to reduce pain but also may
be useful for self-injurious behavior (SIB). In the current investigation, a
microcurrent electromedical device, classified as a transcutaneous electrical
nerve stimulator (TENS), was applied with a man with Down syndrome who displayed
SIB that persisted in the absence of social contingencies. Although clinically
significant results were not maintained, a clear difference in the rates of SIB
during active and inactive TENS was observed.
PMID- 9757589
TI - UV light affects cell membrane and cytoplasmic targets.
AB - For a long time DNA has been regarded as the only molecular cellular target for
UVB and UVC. However, evidence is accumulating that ultraviolet light (UV) can
also affect cytoplasmic and membrane structures. It has been shown that UV can
directly affect cytoplasmatically located transcription factors, kinases closely
located to the cellular membrane and even membrane receptors. The identification
of additional cellular UV targets and the mechanisms by which these targets
transduce the UV signal will increase the understanding of the biological effects
of UV. Recently, we observed that UV can interfere with cytokine signalling and
induce apoptosis via direct activation of apoptosis-related surface receptors.
These findings will be briefly reviewed in the paper.
PMID- 9757590
TI - Flow cytometric quantification of UV-induced cell death in a human squamous cell
carcinoma-derived cell line: dose and kinetic studies.
AB - Exposure to ultraviolet (UV) radiation and photochemotherapy induces apoptotic
cell death in epidermal cells. In this study annexin V binding and propidium
iodide (PI) uptake have been measured by flow cytometry to evaluate UV-induced
cell death in the human squamous cell carcinoma-derived cell line A 431.
Physiological and therapeutical relevant doses of UVA, UVA1, UVB, narrow-band UVB
(311 nm) and photochemotherapy using 100 ng/ml of 8-methoxypsoralen (8-MOP) with
UVA or UVA1 (PUVA or PUVA1) have been applied. Doses ranged from 8 to 96 J/cm2
for UVA1 and UVA, from 8 to 128 mJ/cm2 for UVB, from 256 to 4096 mJ/cm2 for
narrow-band UVB (311 nm) and from 1 to 16J/cm2 for photochemotherapy. Results
show that the amount of annexin V binding, a measure of early apoptosis, as well
as PI uptake, a parameter of ultimate cell death, are strictly correlated with
the applied UV dose. Peak values of annexin V-positive cells are noted 12 h after
UV exposure in all protocols and are followed by an increase of PI-uptaking cells
with peak values at 24 h after UVA and UVA1, and 48 h after PUVA, PUVA1, UVB and
narrow-band UVB. To compare the effect of different wavelengths and light
sources, dose equivalents are calculated based on the induction of 50% cell death
(as determined by PI uptake). The equivalents are 96 J/cm2 for UVA and UVA1, 16
J/cm2 for PUVA and PUVA1, 256 mJ/cm2 for UVB and 2048 mJ/cm2 for narrow-band UVB.
Our results establish annexin V/PI double staining as an appropriate method for
the quantification of UV-induced cell death. Moreover, they provide a basis for
further investigations concerning mechanisms and modifications of UV-induced
apoptosis.
PMID- 9757591
TI - Cellular target of UVB-induced DNA damage resulting in local suppression of
contact hypersensitivity.
AB - Experimental data are reviewed that lend support to the hypothesis that formation
of DNA damage is the initiation event of local suppression of contact
hypersensitivity (CHS) after exposure to ultraviolet (UV) radiation and that the
antigen-presenting cell (APC) is an important target for this DNA damage.
PMID- 9757593
TI - The potential role for urocanic acid and sunlight in the immune suppression
associated with protein malnutrition.
AB - Irradiation of skin by sunlight or ultraviolet B (UVB, 290-320 nm) brings about a
downregulation of cell-mediated immunity. An action spectrum for photoimmune
suppression in mice indicates that trans-urocanic acid absorbs UV photons and is
isomerized to the cis-isomer in the stratum corneum. Cis-urocanic acid is
subsequently shown to suppress cellular immunity in mice. When histidine is
elevated in a mouse diet, a higher level of urocanic acid is detected in mouse
skin. These mice are more susceptible to photoimmune suppression. There is
evidence that humans and animals experiencing protein malnutrition have very high
levels of urocanic acid and/or histidine. Urocanic acid is formed by deamination
of histidine in one enzymatic step. We discuss the protein malnutrition of
kwashiorkor patients. They experience suppressed immunity and disturbed histidine
metabolism. Here, we present a testable hypothesis: one cause of the immune
deficiency observed in humans with protein malnutrition is the photoconversion by
UVB of increased levels of trans-urocanic acid in skin to cis-urocanic acid,
which suppresses the cellular immune system.
PMID- 9757592
TI - Urocanic acid and cutaneous antigen presentation.
AB - Exposure to UVB results in the isomerization of trans-urocanic acid (UCA),
localized in the stratum corneum, to cis-UCA. Cis-UCA can mediate at least some
of the immunosuppressive effects of UVB, though the mechanism of cis-UCA action
remains incompletely defined. Here, we review the evidence that cis-UCA acts
through alterations in cutaneous antigen presentation.
PMID- 9757594
TI - Immunobiology of lipid-modulated UV-carcinogenesis.
AB - Previous studies have demonstrated that high levels of dietary fat exacerbate UV
carcinogenic expression and suppress immunoresponsiveness. The latter may account
for the former response. We have explored this possibility through T-lymphocyte
transfer studies. Groups of HRA.HRII-c/+/Skh hairless mice were fed isocaloric
diets containing high (12%, wt./wt.) or low (0.75%) levels of corn oil and
irradiated 5 days/week (1.0 J cm-2/day) for 11 weeks with filtered FS-40
sunlamps. At weeks nine and 12, enriched T-cells from high-fat donors that had
received 11 weeks of UV were transferred intravenously to low-fat recipients.
Median tumor times for high-fat, low-fat recipient, and low-fat groups were 15.8,
18.5, and 21.6 weeks, respectively. The significantly (P < 0.03) shortened
primary tumor latent period in low-fat-fed animals resulting from transfer of
relatively low levels of T-cells derived from chronically irradiated high-fat
donors demonstrates that the influence of dietary fat upon UV-carcinogenic
expression is, at least partially, mediated via immunologic mechanisms. Further
studies suggest that fat-modulated carcinogenesis can, itself, be regulated
immunologically. A soluble T-14 (mouse squamous carcinoma cell line) cell-free
fraction was injected subcutaneously at axillae and inguen of animals fed the
high-fat diet during the first three weeks of UV or immediately post-UV. At week
four post-UV, animals were challenged with T-14 cells injected subcutaneously at
both flanks. 21 days post-challenge the tumor volumes of low-fat and high-fat
immunized animals were zero versus 593 mm3 for the high-fat group (P < 0.007).
Such treatment significantly (P < 0.03) increases the latent period of UV-induced
primary tumors as well, when compared to non-treated high-fat-fed animals.
PMID- 9757595
TI - A single exposure of solar simulated radiation suppresses contact
hypersensitivity responses both locally and systemically in humans: quantitative
studies with high-frequency ultrasound.
AB - Ultraviolet radiation (UVR)-induced suppression of cutaneous cell-mediated
immunity plays an important role in the development of photocarcinogenesis in the
mouse and a similar role is suspected in humans. Cell-mediated immunity is
readily tested in vivo by measuring the contact hypersensitivity (CHS) response
to topically applied haptens. CHS in humans is usually determine clinically, with
a subjective scoring system. However, these subjective scores cannot be
statistically analysed. This paper compares four methods currently used to
quantify CHS elicitation responses in humans. The data show that ultrasound
images provide the most accurate and reproducible measurements of the clinically
observed CHS response. We also demonstrate that assessment of the primary
allergic response is a useful indicator of the magnitude of the elicitation
response and can be used to avoid severe CHS reactions in volunteers. There are
few human studies investigating the effects of solar simulated radiation (SSR)
exposure on immunosuppression. In this study we demonstrate SSR is highly
immunosuppressive in all subjects tested. Irradiating a small area of skin with a
single exposure to 3MEDs of SSR completely suppressed CHS both locally (12/12
volunteers) and systemically (10/12 volunteers). Our data do not support a role
for a genetic susceptibility to UVR-induced immunosuppression in humans.
PMID- 9757596
TI - Efficacy of micronized titanium dioxide-containing compounds in protection
against UVB-induced immunosuppression in humans in vivo.
AB - Micronized pigment-containing sunscreens may provide a good alternative to
chemical sunscreens in protection against ultraviolet (UV) B-induced
immunosuppression. The metal particles in these products are likely to remain on
the skin surface where they can offer broadband protection for both the UVA and
UVB regions. We have tested the protective capacity of three titanium dioxide
(TiO2)-containing compounds in humans in vivo. The effect on sunburn cell
formation has been investigated using transmission electron microscopy, while the
mixed epidermal cell lymphocyte reaction (MECLR) has been used as a model for
immunosuppression. Furthermore, the influence of titanium on the integrity of the
stratum corneum barrier (intercellular lipids and desmosomes) has been examined
using freeze fracture electron microscopy. We find that all three compounds
protect against sunburn cell formation. The immunoprotection studies show that
one of the three compounds does not prevent UVB-induced changes of the MECLR
responses. Application of this compound without subsequent UVB irradiation also
induces a significant decrease of the MECLR responses. Moreover, the same
compound affects the intercellular lipid layers, and desmosomes cannot be
detected. The deleterious effect of this compound is probably caused by an
incomplete hydrolysis during the TiO2 synthesis. Our findings indicate that
micronized pigment-containing compounds can offer good protection against short
term UVB-induced immunomodulation in humans in vivo. However, accurate screening
of the synthesis of these compounds is a prerequisite for their safe use as
sunscreening agents in human subjects.
PMID- 9757597
TI - Enhancement of tumour response to photodynamic therapy by adjuvant mycobacterium
cell-wall treatment.
AB - Mycobacterium cell-wall extract (MCWE) is a potent non-specific immunostimulant
that elicits a local inflammatory response associated with antitumour activity.
Tumour-localized administration of MCWE has been examined as an adjuvant to
photodynamic therapy (PDT) mediated by the photosensitizers Photofrin,
benzoporphyrin derivative monoacid (BPD), metatetrahydroxyphenylchlorin (mTHPC),
or zinc (II)-phthalocyanine (ZnPc). A single MCWE treatment, given immediately
after light treatment of murine EMT6 tumours, potentiates the curative effect of
PDT. A similar enhancement of tumour response to Photofrin-based PDT is obtained
with the live Bacillus Calmette-Guerin (BCG) vaccine. Despite differences in the
kinetics/intensity of damage induction to tumour microvasculature and other
characteristics underlying the mechanism of antitumour activity of Photofrin,
BPD, mTHPC and ZnPc, there appear to be no marked differences in the therapeutic
benefit of adjuvant MCWE therapy combined with the PDT mediated by these various
photosensitizers. This may be related to the fact that MCWE elicits a wide range
of immunomodulatory effects that could amplify and sustain the
inflammatory/immune responses triggered by PDT. The enhancement of inflammatory
effector cell activity is indicated by the increased infiltration of neutrophils
and other myeloid cells at the expense of malignant cells found in the MCWE plus
mTHPC-based PDT treatment group compared to the PDT-only group.
PMID- 9757598
TI - Therapeutic photoimmunology: photoimmunological mechanisms in
photo(chemo)therapy.
AB - Ultraviolet radiation, either alone or in combination with photosensitizing
agents, is widely used for the treatment of skin diseases. The efficacy of photo-
and photochemotherapeutic modalities is thought to result, at least in part, from
the induction of immunomodulatory effects. In particular, UV radiation has been
shown to affect (i) the production of soluble mediators, (ii) the expression of
cell-surface receptors and (iii) to induce apoptosis in pathogenetically relevant
cells. UVB radiation-induced immunomodulatory effects are limited to the
epidermis, whereas UVA radiation affects both epidermal and dermal cell
populations. UVB and UVA radiation can exert essentially identical
immunomodulatory effects, which result, however, from different photobiological
mechanisms.
PMID- 9757599
TI - Effects of armrests on workload with ten-key operation.
AB - The constrained posture used for work using a visual display terminal (VDT), such
as data entry, can produce static muscular fatigue. Based on the application of
ergonomic principles, we conducted an experiment using a prototype VDT chair
designed with an armrest adjustable to heights from 22 to 28 cm. The experiment-
conducted to assess the static muscular strain based on varying heights of the
armrest and distance from the keyboard--was performed with male subjects. The
subjects were asked to input five-figure numbers using the 10 keys arranged on
the right side. Using a surface electromyogram, we measured the strain imposed on
the arm and the shoulder. This was followed up with a performance, weight-loading
onto the armrests and a questionnaire. Results show that use of armrests is
effective for the alleviation of muscles in one-handed keyboard operation where
operators work on a desk whose height is unadjustable according to their body
height or where operators are unable to rest their wrist on the desk. A chair
with height-adjustable armrests is considered desirable when used by several
people.
PMID- 9757600
TI - A new aspect of the carotid body function controlling hypoxic ventilatory decline
in humans.
AB - Ventilatory response to eucapnic sustained mild hypoxia was measured in one
patient with unilateral and three patients with bilateral carotid body (CB)
resection (defined UR and BR, respectively). The profile of ventilatory response
in UR patient was initially augmented then gradually declined (biphasic pattern)
as generally seen in normal subjects although the absolute magnitude was
substantially low. On the other hand, biphasic pattern was disappeared in all
three BRs. Lack of hypoxic ventilatory decline (HVD) in the late period of
sustained hypoxia was in marked contrast to that reported in the anaesthetized
and CB-denervated animals whose ventilation was severely depressed lower than the
pre-hypoxic control level. In view of recent knowledge that the analogous mild
hypoxia in normal animals and humans elicits an useful adaptation to economize
energy expenditure with maintaining reversible excitability in control of
respiration, BR patients were considered to have lost this ability. We conclude
that in awake humans the CB not only stimulates ventilation but also controls the
degree of subsequent HVD during sustained hypoxia.
PMID- 9757601
TI - Comparison of cardiac response to managerial workload between men and women.
AB - The aim of the study, was to estimate the reaction of selected circulatory system
parameters to psychic workload in industrial managers and to answer the question
whether may affect this reaction. The study was performed in 23 men (mean 46 +/-
6 years of age) and 16 women (mean 42 +/- 6 years of age), employed as executives
in a large industrial plant. The subjects had their 24-h ECG recorded using
Medilog 3000 (Oxford). The ECG recordings were classified as pathological
according to the standards of Bjerregaard. Heart rate was calculated for working
time, leisure time and sleep. The subjects were also asked to estimate the
perceived psychic load according to a method involving subjective estimation of
work-demands and of an ability to cope with them. Generally, the subjects
reported high work demands, but coping abilities were higher than work demands.
Both in the men and women, a relationship was found between the intensity of
subjective estimation of psychic load and heart rate response. However, the
reaction of the circulatory system to the psychic workload in men was long
lasting (its effects continued until late at night); in women it was more direct
(only during work). The frequency of abnormalities in 24-h Holter ECG recordings
for both test groups was not very high, a little higher in men (30%) than in
women (25%), and was comparable with the frequencies in selected general
population groups. Our results may indicate that mental workload of the
managerial staff, does not cause increased frequency of ECG abnormalities.
However, in view of the fact that cardiovascular diseases are more frequent among
men than among women, different reaction of the circulatory system to workload
should also be accounted for in an attempt to explain the sources of that
phenomenon.
PMID- 9757602
TI - The effect of high-salt diet intake on muscular exercise ability in young
Japanese women.
AB - This study was designed to test whether high-salt diet intake has some acute
impaired effect to the muscular exercise ability due to the calcium deficit in
muscle cell via the accelerated sodium-calcium exchanger. Six healthy young
Japanese women (aged: 22.3 +/- 1.9 yr) performed two types of muscle strength
tests and ramp mode cycle ergometer exercise until exhaustion after normal- (NaCl
is approximately 5.6 g) and high-salt (21.0 g) controlled diet intake on two
separate days in random order. The urinary sodium excretion sampled during 12
hours on the high-salt diet day was significantly higher compared to that of
normal-salt diet day (3301 +/- 992 vs 1595 +/- 540 mg; P < 0.05), while there was
no substantial difference between the urinary calcium excretion in high- and
normal-salt diet days (58.6 +/- 19.7 vs 55.0 +/- 17.2 mg; ns). There were no
significant differences in back strength, repeated maximal hand grip exercise
ability, and VO2max and duration time during ramp exercise between high- and
normal-salt diet conditions. It was concluded that high-salt diet intake even
exceeding 20 g per day had substantially no acute effect on muscular exercise
ability in young Japanese women.
PMID- 9757603
TI - Usefulness of computer-assisted portable EEG recorder for field work in applied
human science.
PMID- 9757604
TI - A preface to the discussions in gender difference.
PMID- 9757605
TI - Harmony in men and harmony in women.
PMID- 9757606
TI - Men's time, women's time--sex differences in biological time structure.
PMID- 9757607
TI - Male brain and female brain.
PMID- 9757608
TI - The brave New World of advanced practice: credentialing and privileging.
PMID- 9757609
TI - Caught in the cross fire of change: nurses' experience with unlicensed assistive
personnel.
AB - Under tremendous pressure to contain costs, most U.S. hospitals are radically
altering the composition and skill mix of their staff, thinning their skilled
registered nurse (RN) ranks, and often substituting them with minimally trained,
lower paid, unlicensed assistive personnel (UAP). Twelve staff nurses were
interviewed to illuminate the experience of working with UAP, who function
largely in untested, expanded roles. Only two nurses viewed this experience
positively; the rest were either opposed to or had strong reservations about UAP
use. Confusion and emotional turmoil predominated as these nurses struggled to
maintain safe, comprehensive care with the assistance of UAP who were often
ambivalent and sometimes dangerously inept.
PMID- 9757610
TI - Women's knowledge of osteoporosis.
AB - Osteoporosis affects one in four women over the age of 65 and is a major cause of
hip fractures that place women in nursing homes. In this study of 247 women,
their knowledge of osteoporosis was assessed with the Facts on Osteoporosis Quiz.
The instrument measured their responses to questions about self-care practices
related to risk factors and preventive behavior associated with osteoporosis.
Respondents came from occupational and primary health care settings and a health
fair. The women ranged in age from 22 to 84 years. Findings indicated that the
majority of women had inadequate knowledge of osteoporosis risk factors and
preventive behavior.
PMID- 9757611
TI - Falls in a psychiatric unit.
AB - The purposes of this descriptive study were to document the prevalence of
previously identified risk factors for falls in a group of acutely ill
psychiatric patients, to determine if patients who fell differed from nonfallers
with respect to risk factors, and to describe the circumstances surrounding falls
that occurred on an inpatient unit. All patients admitted to an acute psychiatric
unit during a 7-month period were entered into the study (N = 197). Twice a day,
nurses who worked on the unit completed a fall-risk factors checklist for each
patient. When a fall occurred, an additional instrument designed to measure
circumstances associated with the fall was completed. The most frequently
occurring risk factors were clinical diagnoses of depression and confusion or
disorientation. Seventeen patients fell during their hospitalization. Compared
with nonfallers, patients who fell were more likely to have a previous history of
falls, generalized weakness, confusion or disorientation, difficulty with
mobility or walking, elimination problems, and temperature elevation. Analysis of
circumstances surrounding falls showed that the majority of falls occurred when
patients were attempting to get out of bed, walk to the bathroom at night, or
change from a sitting to a standing position. Findings from this research can be
used to identify psychiatric patients who are at risk for falls during their
hospitalization.
PMID- 9757612
TI - Clinical nurse researchers' perceptions of hospital nursing research committees:
results of a national survey.
AB - A growing body of literature portrays sharpening controversy over the appropriate
roles and functions of hospital nursing research committees (HNRCs). This
descriptive study examined 139 clinical nurse researchers' experiences with
HNRCs. Nurse researchers who were members of HNRCs had more positive attitudes
towards HNRCs on all three scales of the HNRC-Questionnaire than nurses who were
not members of HNRCs. Researchers who were prepared with Master's degrees had
more positive attitudes on the HNRC Role Scale than researchers with doctoral
degrees. Narrative comments written on the questionnaire reflected a substantial
diversity of opinions regarding HNRCs. The results suggest that novice,
nondoctorally prepared researchers may perceive the assistance of some HNRCs as
beneficial, whereas doctorally prepared researchers tend to perceive them as
obstacles.
PMID- 9757613
TI - Quality of life in systemic lupus erythematosus.
AB - This study reports the impact of systemic lupus erythematosus (SLE) on the
quality of life of 37 SLE patients by using two quality of life (QOL)
instruments, the Sickness Impact Profile and the Arthritis Impact Measurement
Scale 2. Findings suggested that SLE affects all areas that are considered
essential for QOL including alertness behavior, recreation/pastime, sleep and
rest, home management, social interaction, and emotional balance. Findings
suggest that in the management of chronic illnesses such as SLE, QOL assessments
may provide health care professionals with data that would enhance the likelihood
of designing holistic interventions.
PMID- 9757614
TI - Health problems and health actions among community-dwelling older adults: results
of a health diary study.
AB - This study examined the health problems and health actions reported by a sample
of older adults (N = 60) who maintained health diaries over a 4-week period. The
diary sample was 78% (n = 47) White; 52% (n = 31) were women, with a mean age of
75 years (SD = 5.3). Content analysis was used to examine the types of health
problems reported in the diaries, which health problems were likely to be
considered an illness, and what health actions were reported. Respondents
reported an average of four different types of health problems over the 4-week
diary period. There were differences in symptom reports related to gender, age,
or race. The most frequently reported health problems were musculoskeletal
problems (n = 38), runny nose and respiratory problems (n = 24), gastrointestinal
problems (n = 22), and headaches (n = 22). Only 36% of all health problems were
considered to be illnesses. Subjects recorded a number of health actions in
response to their health complaints, including over-the-counter (OTC) medication
use (83%), prescription medication use (53%), self-care activities (72%), and
professional consultation (43%). Specific strategies that subjects used to deal
with various health problems, implications of the findings, and the usefulness of
health diaries as a clinical tool are discussed.
PMID- 9757615
TI - Recruitment and retention of women in nontherapeutic clinical trials.
PMID- 9757616
TI - Research interest groups: an approach to integrating research into the practice
setting.
PMID- 9757617
TI - Cerebral lymphomas in AIDS. Neuropathological study.
AB - A morphological analysis was done of 15 cases of malignant cerebral lymphomas
selected from the material of 160 brains of patients, who died in the course of
full-blown acquired immune deficiency syndrome (AIDS) during the period of 1987
1997. Cases with cerebral lymphomas comprised 9.4% of the whole collection. There
were 13 males and 2 females in the studied group. The patients age ranged from 25
to 61 years. In 10 cases lymphomas were localized solely in the central nervous
system, and in further 4 they were accompanying systemic neoplastic process. In
one case lack of clinical and autopsy data did not permit classification of
neoplasm to the primary or to the secondary group. In 13 cases immunophenotype of
the lymphomas was characterized by immunohistochemical methods. In 11 cases
neoplastic cells originated from B cells line and in 2--from T cells line. In 10
cases lymphomas were found in macroscopic examination, in the remaining 5 cases
they were disclosed at the brain histopathology. The dynamics and extensiveness
of the neoplastic process were different in particular cases. In most of them the
process was multifocal and manifested in the form of diffuse proliferation,
formed tumors with changing nature of their delineation and as multilayer
perivascular cuffs. The characteristic feature of diffuse neoplasmatic growth was
the appearance of large coagulative necroses in the central parts of tumors.
Neoplastic foci were localized most often in the cerebral hemispheres (white
matter, basal ganglia, periventricular regions), less frequently in the brain
stem and cerebellum. In one case diffuse lymphoid growth involved selectively
leptomeninges. In most of the cases leptomeningeal infiltrations accompanied
large parenchymal neoplastic foci. The most striking feature of our collection
consisted in concomitance of cerebral lymphomas with HIV-specific brain pathology
and/or opportunistic infections mostly of viral etiology. Their frequency was
much higher than in cases of AIDS without cerebral lymphomas. Another finding
which seems to be worth mentioning was the appearance of morphological exponents
of various pathological processes such as for instance multinuclear giant cells,
CMV inclusions within neoplastic tissue. The relatively frequent presence of
numerous HIV-specific giant cells on the periphery of lymphomatous tumors
suggests pathogenetic participation of immune deficiency virus in the
blastomatous transformation of lymphoid cells within the central nervous system.
PMID- 9757618
TI - Olfactory neuroblastoma (esthesioneuroblastoma) and esthesioneuroepithelioma:
histologic and immunohistochemical study.
AB - Two cases of olfactory neuroblastoma (ONB) representing two morphological
variants of the tumor are described. Case 1 exhibited a neuroblastoma-like
histological pattern corresponding to the usually reported type of ONB--the
esthesioneuroblastoma, whereas in case 2 a very rare variant of ONB-the
esthesioneuroepithelioma was recognized. The histological and immunohistochemical
differences between the cases are discussed with regard to still controversial
opinions concerning the subclassification of ONB and the histogenesis and
clinical prognosis of these tumors.
PMID- 9757619
TI - Does the pathological factor in amyotrophic lateral sclerosis (ALS) damage also
astrocytes?
AB - Introduction of immunocytochemical reaction to glial fibrillary acidic protein
(GFAP) made possible more accurate estimation of astrocytes reactivity in various
diseases of CNS, among others, in amyotrophic lateral sclerosis (ALS). Lack of
present studies concerning reactive astroglia in spinal cord, inclined us to
examine the reaction of astrocytes in cervical, thoracic and lumbar spinal cord.
Material included 11 sporadic ALS patients. Sections of formalin-fixed, paraffin
embedded tissue were stained with hematoxylin and eosin, Kluver-Barrera method
and with antibody against GFAP. In all cases various degree of nerve cells loss
in the anterior horn, pigmentary degeneration of remaining neurons, the pallor of
myelin in the white matter of anterior and lateral columns were observed. In a
part of cases background tissue rarefaction within anterior horn was seen.
Intensity of morphological changes within anterior horns made possible to divide
material into two groups and separate one senile case. Very intensive neuronal
changes associated with weak reaction of astrocytes in the anterior horn allow us
to pose the hypothesis of influence of an unknown pathological factor on both
anterior horn neurons and astrocytes.
PMID- 9757620
TI - Quinolinic acid and sigma receptor ligand: effect on pyramidal neurons of the CA1
sector of dorsal hippocampus following peripheral administration in rats.
AB - Male Wistar rats, weighing 200-220 g, were used in the study. Quinolinic acid and
racemic pentazocine were administered alone or together. Quinolinic acid was
administered intraperitoneally (i.p.) in a dose of 60 mmol, racemic pentazocine
intramuscularly in a dose of 2 mg/kg, once every 24 h for 8 days. The control
group received 1 ml of saline i.p. once daily for 8 days. Pentazocine alone
produced no signs of alteration in the hippocampal formation. Quinolinic acid
produced neurotoxic effect in the CA1 area of the hippocampal formation. The
presence of the dark-degenerated pyramidal cells was a common sign of a delayed
excitotoxic effect. Pentazocine added to quinolinic acid markedly attenuated the
neurotoxic effect of quinolinic acid. In such cases, only single dark degenerated
cells were seen.
PMID- 9757621
TI - The effect of Dotarizine--(Ca2+ channel blocker)--on vascular reactivity and
ultrastructure of cerebral capillaries in animals subjected to anoxia.
AB - Dotarizine--the novel piperazine derivative--belongs to wide spectrum Ca2+
channel antagonists. It was reported to have strong vasodilatatory and
antiserotoninergic activities. Comparing with other Ca2+ channel blockers
Dotarizine was found to have lower oral toxicity. In the present study the
influence of the oral administration of the novel compound on the blood flow
velocity changes in different cerebral arteries--in basilar artery (BA) and
middle cerebral artery (MCA)--was investigated under hypoxic conditions. The
ultrastructural morphological changes of intracerebral vessels endothelium in
treated and untreated anoxic animal groups were also demonstrated. The
experiments were carried out on rabbits. In the experimental group 25 mg/kg of
Dotarizine dissolved in 0.25% agar was administered orally three times at the 10
hours' intervals. The sham group of animals was fed with agar of the same
concentration. During anoxic conditions strong vasodilatory effects were observed
in both investigated vessels of drug-treated animals. In the experimental group
marked ultrastructural differences in parenchymal vessel endotheliumin comparison
to sham group were revealed. Thus, the oral administration of Dotarizine might
have effect on the various parts of the cerebrovascular system and can play
significant role in improvement of various cerebrovascular disorders.
PMID- 9757622
TI - Characterization of thiamine pyrophosphatase positive phagocytic cells in the
neural lobe of rat pituitary.
AB - Here, using a histochemical staining for a microglia/phagocyte marker TPP-ase
(Murabe, Sano 1981), and an electron microscopy we characterized the population
of pituitary phagocytic cells activated by cerebral ischemia. An intense thiamine
pyrophosphatase (TPP-ase) activity was demonstrated in glial cells and some cells
of blood vessels of neural lobe, late period (12 months) after experimental
ischemia. TPP-ase positive cells were ultrastructurally identified as pituicytes,
microglia, pericytes and perivascular cells. The product characteristic for TPP
ase activity was seen on plasma membrane of these cells. Our electron-microscopic
histochemical results provide strong support for a role of pituicytes, pericytes
and perivascular cells as a phagocytic cells involved in mechanism of elimination
of ischemically damaged axonal endings in neural lobe.
PMID- 9757623
TI - Bilateral sciatic nerve entrapment due to weight loss.
PMID- 9757624
TI - Massive hemothorax after low impact blunt chest trauma: a case report.
PMID- 9757626
TI - New HIV/AIDS cases decline overall but increase among women, minorities.
PMID- 9757625
TI - Angina and atrial fibrillation in a patient with thyrotoxicosis.
PMID- 9757627
TI - Radiological case of the month. Acute appendicitis.
PMID- 9757629
TI - Information and quality healthcare outpatient diabetic management project.
PMID- 9757628
TI - Colorectal cancer--chemoprevention.
AB - Colorectal cancer is the second leading cause of death from cancer in The United
States. During the last fifteen years, emphasis has been placed on identification
of high risk patients and families and outline of appropriate surveillance
regimens for normal and high risk patients for colorectal cancer. Parallel to
this effort, abundant clinical data has been accumulated that chemoprevention of
colorectal cancer with nonsteroidals and aspirin may be possible. Interruption of
prostaglandin metabolism appears to be one of the mechanisms of action but not
the only therapeutic arm. Currently, sulindac, aspirin, calcium and selenium
supplementation are attractive recommendations to at risk patients awaiting
results of clinical trials. Other agents in development add excitement to the
concept of colorectal cancer chemoprevention.
PMID- 9757630
TI - [Cases of multiple ventricular septal defects].
AB - We had 4 cases with multiple ventricular septal defects (VSDs) in complexed
congenital heart disease. One of four had two separate VSDs detected by two
dimensional echocardiography before operation. Second of four had additional
infundibular muscular VSD which was detected by echocardiography in the intensive
care unit (ICU) after patch closure of a perimembranous VSD. The third case had
two additional VSDs of inlet muscular and subaortic septum detected by
transesophageal and direct echocardiography during reoperation, beside a
subpulmonary VSD which was originally diagnosed before Jatene operation for
double outlet right ventricle. The fourth case had multiple trabecular muscular
VSDs diagnosed by postoperative angiography soon after Rastelli operation. Since
these additional multiple VSDs compromise the postoperative hemodynamics if those
are unrecognized, it is indispensable to detect all VSDs before operation, using
transthoracic and transesophageal echocardiography.
PMID- 9757631
TI - [Application of heparin-coated PCPS for traumatic cardiac rupture: report of a
case].
AB - Application of heparin-coated percutaneous cardio-pulmonary support system (PCPS)
for a case with traumatic cardiac rupture is reported. A 50-year-old woman, who
was injured in the traffic accident, was admitted to our hospital. Her
consciousness was not alert in circulatory collapse. Echocardiography showed
cardiac tamponade and pericardial centesis was done followed by re-filling.
Urgent surgical intervention was necessary. When she was brought to operating
room, she became cardiac arrest, necessitating cardio-pulmonary resuscitation
followed by PCPS. Under PCPS support, hemodynamic state became stable and cardiac
laceration was repaired. Laparotomy was also done because of the distension of
abdomen during operation, and splenectomy was necessary for the injured spleen.
She is doing well now. Generally, it is considered to be contra-indicated to
apply PCPS for traumatic cases which may cause bleeding tendency because of anti
coagulant therapy. But this case report showed the possibility of application of
PCPS for traumatic cases, if PCPS is established using heparin-coated system.
PMID- 9757632
TI - [Coronary artery bypass grafting performed by the simple and convenient graft
supporter].
AB - We have experienced a simple, safe and convenient technique for supporting the
arterial or saphenous vein graft in the coronary artery bypass grafting. This
graft supporter is made of cotton cloth with a 50 percent polyester mix. The
supporter is twenty centimeters long and two centimeters wide. This supporter
provides the complete fixation of the graft without the holding by the co
operater. Therefore the supporter allows very easy, safe and accurate graft
anastomosis with the native coronary artery or the ascendinbg aorta. No
complication was encountered in association with this procedure in 127
operations.
PMID- 9757633
TI - [Use of the radial artery graft in coronary artery bypass grafting: harvesting
technique and spasm prevention].
AB - The use of radial artery (RA) in coronary artery bypass grafting (CABG) has been
increasing recently as a revival. In this report, we describe several practical
suggestions for improving patency rate of the graft. Between April of 1997 and
February of 1998, 41 CABGs were performed using RA graft, totalling 56
anastomoses. The early patency rate of the graft has been 100% (graft: 38/38,
anastomosis: 53/53). Harvesting technique: with the use of Harmonic Scalpel, it
is possible to atraumatically harvest the vessel in a short time. Although
longitudinal fasciotomy of the adventitia has been recently reported to be
effective in releasing spasm, the nature of the vessel raise concern that the
fasciotomy may even induce spasm. We hypothesize that leaving the adventitia
intact, preserving vasa vasorum, rather than performing fasciotomy leads to
improvement of long-term patency. Spasm prevention: we consider the body
temperature to be the most important factor. Therefore, we utilize normothermic
cardiopulmonary bypass (CPB). Another important factor is that the arterial CO2
is kept at a high level during CPB. For dilation of RA graft, milrinone is used
instead of papaverine. For the intra- and postoperative management, intravenous
continuous administration of diltiazem was changed to nicorandil. Technically,
essential resolution for improvement of patency rate is either to allow for large
proximal anastomosis, or to make sequential anastomosis with another coronary
artery which has a good run off. For these purposes, the proximal anastomosis on
the ascending aorta seems to have the advantage over placing it on ITA.
PMID- 9757635
TI - [A 13-year-old male with a funnel chest treated by sternal elevation].
AB - A 13-year-old male with a funnel chest was treated by sternal elevation method.
Reconstruction was performed by resection of rib cartilage, wedge osteotomy of
the anterior site of the sternum, sternal elevation by placement of a titanium A
0 plate under the sternum, and fixation of the wedge osteotomy site by a titanium
plate. After surgery, the chest wall deformity was improved remarkably without
complication. Although the A-0 plate was removed 19 months after surgery due to a
break in the plate, cosmetic and functional results are now excellent 28 months
after surgery.
PMID- 9757634
TI - [Partial median sternotomy for pediatric cardiac surgery].
AB - In order to minimize scar appearance and thereby improve postoperative cosmetic
appearance for pediatric cardiac surgery patients, we performed partial median
sternotomy incisions. A short midline incision, from 1 to 2 cm below the
articular notch of the 2nd rib to the xiphoid process, was made. The sternum was
divided from the xiphoid process to the articular notch of the 2nd rib. The
thymus was mobilized and the pericardium incised longitudinally. The aorta and
superior and inferior vena cava were mobilized to facilitate direct cannulations.
Cardiopulmonary bypass was instituted in the usual fashion. From June to December
1997, 14 patients between the ages of 4 days and 12 years have undergone cardiac
repair using this technique. Cases included 7 VSD (including 4 pulmonary
hypertension and 1 DCRV), 5 ASD, 1 ECD and and 1 DORV with mitral atresia. All
patients were extubated within 3 hours after surgery, and there were no wound
infections or hospital mortalities (except one 4 day old baby who died by LOS on
the 16th postoperative day). In our experience, this approach is safe and
provides good exposure with excellent cosmetic results.
PMID- 9757636
TI - [Concomitant cardiac and pulmonary operation, the profits of not using cardio
pulmonary bypass].
AB - We performed off pump CABG (coronary artery bypass grafting) and right upper
lobectomy with R2a lymph nodes dissection on the patient suffered from both lung
cancer in the right S1 and stenotic lesion in the left anterior descending
artery. Because the coronary lesion was long-segmented one, it was not suitable
for percutaneous transluminal coronary angioplasty. To perform absolutely
curative operation for the lung cancer, CABG was undergone simultaneously under
off pump condition. It is generally feared that the cardiovascular surgery under
CPB may have adverse effect for the patient with malignant lesion. Off pump CABG
is expected to avoid such disadvantage of CPB, and thought to be suitable method
for such a patient as we present above.
PMID- 9757637
TI - [CABG after patch angioplasty of the left main coronary: artery report of a
case].
AB - A 57-year-old man was admitted to our hospital because of restenosis of the left
main coronary trunk (LMT) after patch angioplasty for the LMT lesion. PTCA was
repeated four times during three years after patch angioplasty, but recent
coronary angiogram still demonstrated 75% restenosis of the LMT lesion. Double
CABG was performed to LAD and LCX using the left internal thoracic artery and
saphenous vein graft. Postoperative coronary angiogram revealed an excellent
result. A careful consideration must be given to the indication of the patch
angioplasty of the LMT lesion.
PMID- 9757638
TI - [A case of primary cardiac malignant fibrous histiocytoma].
AB - In this article, we report a case of primary cardiac malignant fibrous
histiocytoma. The patient, 74-year-old female, had been treated medically for
heart failure with minimal improvement and was referred to our hospital.
Echocardiogram revealed two cardiac tumors in the left atrium, one of which was
obstructing the inflow of the mitral valve. Emergent surgical resection was
performed successfully with shortterm ICU stay, but the patient died of DIC on
the 24th day after surgery. The pathological examination revealed malignant
fibrous histiocytoma and this report is the 40th case report of this kind of
primary cardiac tumor.
PMID- 9757639
TI - [Re-do surgery with minimally invasive cardiac surgery (MICS): mitral valve
replacement 6 years after open mitral commissurotomy].
AB - A 60-year-old man, who had undergone open mitral commissurotomy 6 years ago,
underwent re-do surgery (mitral valve replacement) with minimally invasive
cardiac surgery (MICS), using lower partial sternotomy to the height of the right
side second intercostal space. Cannulation of the heart was carried out placing a
cannula directly into the superior vena cava and a second cannula in the inferior
vena cava via the right atrium. Arterial return was through the ascending aorta.
Cardioplegia was administered directly into the ascending aorta with intermittent
perfusion. Valve replacement was performed by opening directly right side left
atrium.
PMID- 9757640
TI - [Superimposed infective endocarditis at anterior mitral leaflet in a patient with
prolapsed posterior leaflet: report of a case treated with valvuloplasty].
AB - A 64-year-old male patient was referred to our hospital for massive mitral
regurgitation after infective endocarditis. Echocardiography revealed vegetation
on the atrial surface of the midst of the anterior mitral leaflet. At operation
it was found that the anterior leaflet was perforated due to infection, and the
posterior leaflet was prolapsed resulting from elongated chordae. Anterior
leaflet was patched with autologous pericardium, and posterior leaflet was
repaired with rectangler resection. An autologous pericardial strip was sutured
to posterior mitral annulus. The patient survived the operation without
complication.
PMID- 9757641
TI - [A case of a chronic traumatic thoracic aneurysm with compression of left main
bronchus at the isthmus].
AB - We report a case of traumatic thoracic aortic aneurysm found by occurrence of
pulmonary atelectasis in the chronic phase. The patient, an 18-year-old female,
was hospitalized with multiple trauma caused by a traffic accident. At the time
of hospitalization, no thoracic trauma was found but a fracture of the pelvis and
one leg was recognized. 45 days after the initial trauma, a pulmonary atelectasis
on the left lung was found on a chest X-ray film. By chest CT and angiography,
the pulmonary atelectasis was proved to be caused by compression of the left main
bronchus by a traumatic aneurysm of the thoracic aorta. 55 days after the initial
trauma, resection of the aneurysm and graft replacement was performed.
Postoperative course was satisfactory. In conclusion, possibility of an injury to
the thoracic aorta should be considered on the treatment for the patient with
multiple trauma in the chronic phase as well as in the acute phase.
PMID- 9757642
TI - [A case of constrictive pericarditis reoperated 13 years after pericardiectomy by
left thoracotomy approach].
AB - A 48-year-old male with constrictive pericarditis was reoperated through median
sternotomy 13 years after pericardiectomy through left thoracotomy. Extensive
pericardiectomy is the most important point for constrictive pericarditis.
Therefore, we have recently chosen the median sternotomy approach which has
advantages over the left thoracotomy approach. Namely, the cardiopulmonary bypass
is performed in the former approach immediately if the posterior pericardiectomy
is difficult or the coronary arterial injury happens during decortication.
PMID- 9757643
TI - [A case of infective thoracic aortic aneurysm ruptured to the lung].
AB - We report a successful surgical treatment of an infective thoracic aortic
aneurysm ruptured to the left lung. A 63-year-old man who had been suffering from
fever and cough showed twice of hemoptysis. Chest CT revealed a descending
thoracic aortic aneurysm ruptured to the left lung. A semiemergent operation was
performed. At operation, aneurysm of descending thoracic aorta was found adherent
to the left lung. Aneurysmectomy with left pneumonectomy was carried out. The
postoperative course of the patient was uneventful. Conceivably, in order to
avoid massive intraoperative bleeding during division of dense adhesion and
postoperative graft infection, concomitant lung resection is necessary.
PMID- 9757644
TI - [Thoracoscopic surgery for an aged patient with T1N0 non-small cell lung cancer:
case report].
AB - An 85-year-old woman was referred to our hospital because of an abnormal shadow
in the right upper lung field in chest roentgenograms. CT scans revealed a tumor,
3 cm in diameter at the peripheral field of the upper lobe. The lesion was
diagnosed adenocarcinoma of the lung by transbronchial lung biopsy (c-T1N0M0).
She underwent a partial resection of he S3 in consideration of age and the
clinical stage, by using thoracoscopic procedure. Her postoperative course was
uneventful and she was discharged on the 14th postoperative day. Since then, she
has been free from recurrence for the past 3 years. Thoracoscopic surgery appears
to be useful for aged patients with peripheral early lung cancer because of low
incidence of postoperative disability and complications.
PMID- 9757645
TI - [A case report of small-sized peripheral lung cancer diagnosed by thoracoscopic
biopsy].
AB - A case who had surgical treatment for small-sized peripheral lung cancer
diagnosed by thoracoscopic biopsy was reported. A 66-year-old female was admitted
to our hospital because of evaluation of an abnormal shadow on chest X-ray. Chest
CT showed that the tumor about 7 mm in diameter was situated in right S1b and
suspected to be malignant. Transbronchial lung biopsy and brushing showed no
malignancy. The tumor was finally diagnosed to be well-differentiated
adenocarcinoma by thoracoscopic lung biopsy. Following this procedure, right
upper lobectomy and lymph node dissection (R2a) were performed through postero
lateral thoracotomy at one stage. Pathological diagnosis showed that the tumor
was well-differentiated papillary adenocarcinoma and pathological TNM
classification was T1N0M0. The postoperative course was uneventful and the
patient is now doing well with no relapse at 1 year 2 months after the operation.
PMID- 9757646
TI - [Postoperative chylothorax treated with fibrin glue and absorbent mesh: a case
report].
AB - A 66-year-old man was treated by graft replacement for a thoracic aortic
aneurysm. Chylothorax occurred on postoperative day 2. In spite of cessation of
oral intake and IVH management, chest tube drainage did not decrease, the patient
became malnourished. A chest X-ray and CT scan revealed the massive pleural
effusion. Reoperation assisted with a thoracoscopy was carried out for
chylothorax on postoperative day 27. Because we were unable to find the thoracic
duct and the leakage point, the fibrin glue and absorbent mesh was applied to
parietal and mediastinal pleura. Four days after reoperation, the chest tube was
removed. This method is useful for this type of a chylothorax and lymphorrhea.
PMID- 9757647
TI - [Desmoid tumor of the chest wall: a case report].
AB - A 45-year-old man was referred to our hospital for recurrent desmoid tumor of the
chest wall. He underwent chest wall resection with reconstruction of Marlex mesh.
But we could not resect it enough widely, because the tumor invaded beside left
subclavian artery and subclavian vein, brachioflexus. So he had additional
radiation therapy (50 gry). The patient is now doing well without recurrence 1
year after the operation.
PMID- 9757648
TI - [Enchondroma protuberance with destroying the rib: report of a case].
AB - A 18-year-old female was admitted to our hospital because of a mass shadow in the
left upper lung field on chest roentgenogram of a medical check. Computed
tomography and magnet resonance imaging of the chest revealed a tumor which
located in the left 5th rib, and was unclearly demarcated to the rib. Under the
diagnosis of a rib tumor, the patient was treated by radical en bloc excision.
The pathologic diagnosis was enchondroma protuberance of the rib. This tumor may
be indistinguishable from osteochondroma or chondrosarcoma. Therefore, total
resection is recommended for accurate diagnosis and absolute cure.
PMID- 9757649
TI - [A resected case of a bronchiolo-alveolar cell carcinoma of the lung accompanying
pneumonia-like shadow on chest roentgenogram].
AB - A 67-year-old female was admitted to our hospital because of pneumonia-like
shadow on chest roentgenogram with persistent cough and sputum of 4 months
duration. Diagnosis as lung cancer was delayed more than 4 months. She showed
fever and inflammatory reactions. Antibiotics were effective to inflammatory
reactions, but not effective to pneumonia-like shadow. Transbronchial lung biopsy
was useful for the diagnosis. Right lower lobectomy was performed. In this case,
tumor extents were limited within one lobe. Tumor cells did not invade blood and
lymphatic vessels, and extrathoracic metastases were not detected. The prognosis
of bronchiolo-alveolar cell carcinoma was determined by intra-pulmonary tumor
extent. Based on a comparison with the outcome of unresected cases, bronchiolo
alveolar cell carcinoma limited within one lobe should be surgically resected.
PMID- 9757650
TI - [Esthesioneuroblastoma: review of literature and case report].
AB - On the base of literature and the own cases the author showed occurrence,
pathomorphology and treatment of the esthesioneuroblastomas.
PMID- 9757651
TI - [Diagnostic problems in cases of neck tumors].
AB - The authors present diagnostic problems that are faced in cases of neck tumours,
despite the application of modern examination methods. The above mentioned
problems also concern pathological diagnostics. Emphasis is placed on the
opportunity of achieving unbelievable results in ultrasonographic study and
aspiration biopsy in cases of lymphoma and Hodgkin's disease.
PMID- 9757652
TI - [Tumor markers in monitoring of neoplasms].
AB - Prophylaxis, diagnosis, radical treatment and monitoring have a basic
significance in the clinic of head cancers. The aim of the clinical course of
malignant disease preferred prematurely detection of the recurrence. In the
monitoring wide applications have tumor markers. The authors present the results
on the sensitivity of seven biochemical tumor markers (AFP, Ca-9, CEA, TPA, NSE,
ferritin and SCC) in 42 patients with neoplasm of the head. The sensitivity is
for AFP-0%, CEA-10%. Attention was drawn to the relatively high sensitivity for
TPA, NSE, ferritin and SCC, particularly for the neoplasms of oral cavity (TPA
45%, NSE-68%, ferritin-38%, SCC-55%) and the pharynx (Ca 19-9-38%, TPA-63%, NSE
62%, ferritin-42%, SCC-83%).
PMID- 9757653
TI - [Dilemas in the evaluation of post-radiation lesions of the larynx].
AB - The authors analyse the post-radiation lesions in larynx taking into
consideration the cases of coexistence with residual or recurrent tumour. They
underline the difficulties in obtaining a true picture of the condition of the
larynx on the basis of histopathological examination. In a number of cases
repeated histopathological examinations delayed the surgical treatment and thus
caused in some them that the patient's chance to be cured was lost. The authors
characterise clinical symptoms with strongly suggest the presence of tumour in
those cases.
PMID- 9757654
TI - [Clinical evaluation of patients with bilaterally increased lymph nodes in
laryngeal cancers].
AB - Clinical evaluation of patients with laryngeal carcinoma and bilateral neck nodes
examined intraoperatively was performed. Clinical and histopathological analysis
of treatment methods and results was carried out.
PMID- 9757655
TI - [Complications and failure after partial laryngectomy].
AB - The frequency and type of failures and complications after 259 partial
laryngectomies in patients treated for cancer of larynx in Otolaryngology
Department of Medical University of Lodz from 1980 to 1996 were evaluated. Among
the failures a local and nodal recurrence, a distant metastasis and a second
primary malignant tumor were taken into consideration. Furthermore, among the
complications disfunction of breathing, swallowing, voice emission and abnormal
healing were analyzed. The most often failure was local recurrence which had been
observed in 36 patients (13.9%) and the most often complication was a granulation
in larynx which had been observed in 45 patients (17.4%).
PMID- 9757656
TI - [Distant results of putting the feeding tube through wound after laryngectomy].
AB - Authors present their own postoperative results in nourishing the patients after
laryngectomy. Their several years' observations, based on the group of 318
patients, were connected with the risk of the postoperative complications. In
proposed way of nourishing (introduced by B. Latkowski) the point is in putting
the nutritive drain not through the nose, but directly through the cutting during
laryngectomy. The main aim of the research was presenting good points of this
method and existence of no complications with the most dangerous--fistulas.
PMID- 9757657
TI - [Myxoid liposarcoma of the larynx].
AB - The paper presents a rare case of tumor--liposarcoma myxoides of untypical
location--in the area of subglottic larynx. Diagnostic problems that resulted in
erroneous recognition of the case, leading to improper treatment, are discussed.
PMID- 9757658
TI - [Rare malignant tumors of the larynx].
AB - The study presents rare neoplasms of larynx. The authors introduce epidemiology,
clinical history and medical treatment in two cases of adenocarcinoma and one
case of sarcoma. The authors call attention to high malignancy of tumors, early
metastases to neck lymph nodes and distant metastases.
PMID- 9757659
TI - [Laryngeal chondrosarcoma].
AB - The authors showed the laryngeal chondrosarcoma in own materials.
PMID- 9757660
TI - [Multi-stage anatomical-functional reconstruction in surgical treatment of cancer
of the mouth floor and tongue].
AB - Authors present multistage surgical treatment of cancer disease with its radical
dissection and anatomical reconstruction of risected tissue diminution and
consecutive functional reconstruction of organs and tissue elements in later
stage.
PMID- 9757661
TI - [Delto-pectoral flap in reconstruction of esophagus after laryngectomy].
AB - The authors present the case of 67 years old male with carcinoma of larynx and
hypopharynx. The tumor was resected by total laryngectomy enlarged by partial
resection of hypopharynx and esophagus. The reconstruction of hypopharynx and
esophagus was made using deltopectoral flap because with a successful effect.
PMID- 9757663
TI - [On diagnosis and treatment of parotid tumors].
AB - The authors showed diagnosis and treatment of parotid tumours.
PMID- 9757662
TI - [Malignant adenolymphoma-oncocytic adenocarcinoma of the parotid gland].
AB - The authors present an extremely rare case of a malignant form of parotid gland
adenolymphoma treated by surgical intervention. Further, diagnostic problems and
methods of treatment are discussed as well as unsuccessful course of the disease,
due to extensive, distant metastases.
PMID- 9757664
TI - [Salivary gland tumor in authors' material].
AB - The aim this work was to analyze the operated salivary gland tumors, taking into
consideration the age and the sex of the patients. From 1980 to 1996 74 patients
were operated including 40 women and 34 men, aged 21-78. Out of those 74 salivary
gland tumors which were operated, conservative operation was carried out in 62
patients (85.2%) while in 11 patients (14.8%) it was radical operation. Most of
the patients who underwent the operation were at the age between 31 and 60
(77.1%). In most cases--77.2% we had to do with mixed tumor of parotid gland and
in 4% of submaxillary gland. Postsurgery complications in the from of complete
facial paralysis were shown in 14.8% of the patients.
PMID- 9757665
TI - [Head and neck lymphomas in the material of the ENT department of Municipal
Hospital in Gdynia in 1977-1996].
AB - The authors present data relating to patients with malignant lymphoma of the head
and neck diagnosed at the ENT Department, Municipal Hospital in Gdynia, during
the years 1977-1996. The material is analysed in relation to the sex and age of
the patient and the localisation of tumour. Some cases are presented in detail
depending on localisation or difficulties in diagnosis (lymphoma of the larynx
and ethmoidal sinus).
PMID- 9757666
TI - [Non-Hodgkin's lymphoma: diagnostic problems].
AB - The aim of this article was to describe rarely occurred non-Hodgkin's lymphomas
from peripheral lymphocyte T. Epidemiology, course of the disease and
difficulties of diagnostic was described with the special regards of early
diagnostic.
PMID- 9757667
TI - [Thyroid neoplasm with symptoms of carotid body tumor].
AB - The authors present a case of thyroid cancer manifestating itself as carotid body
tumor. Fine needle biopsy performed twice and an arteriography suggested this
diagnosis.
PMID- 9757669
TI - [Atypical localization of polymorphic adenoma].
AB - The authors described 3 cases of adenoma polymorphic located in other than major
salivary gland sitea.
PMID- 9757668
TI - [A skull base tumor complicated by rhinorrhea].
AB - The authors presented a case of rare skull base tumor complicated by rhinorrhoea.
Diagnostic procedures and surgical treatment by laryngo-neurosurgical team was
described.
PMID- 9757670
TI - [Laser surgery in otolaryngology].
AB - The paper presents contemporary methods of using different kinds of lasers for
surgical interventions in otolaryngology. It contains data concerning the
development of laser techniques, the discussion of laser radiation and
classification of different types of lasers. Basing on the authors' personal
experience and the literature, the review of indications and contraindications
for otolaryngological laser treatment has been made and the best kind of laser
has been chosen. The risk factors of laser treatment, both for patients and for
medical staff including various complications is stressed. Moreover, early and
distant treatment results are presented as well as the advantages of using laser
beam and adverse effects. The problems of applying laser treatment in
anaesthesiology are discussed.
PMID- 9757671
TI - [The use of thermography for the laryngeal diagnosis].
AB - Authors presented possibility of clinical appliance of the M 4128 thermocamera in
monitoring thermal changes of the skin and mucosa in upper respiratory tract
diseases in patients treated at ENT Department Medical University of Lodz. Basing
on the obtained results authors conclude usefulness of thermocamera in diagnosis
of the head and neck tumors and inflammatory diseases and monitoring of the
photodynamic therapy.
PMID- 9757672
TI - [The use of CO2 laser in the treatment of leukoplakia of the oral cavity].
AB - During the period from 1992 to 1996 in the Otolaryngological Clinic of the
Medical Academy in Bydgoszcz 20 patients with leucoplakia of the oral cavity were
hospitalized. The treatment with the CO2 laser was used. Depending on the kind of
lesion single or continuous ray of the power 6-15 W were applied. The patients
were divided into 3 groups according to the kind of leucoplakia: patients with
simple leucoplakia, patients with nodular leucoplakia, Patients with verrucous
leucoplakia. According to the size of the leucoplakia area: lesions of 1 cm
diameter, lesions of 2 cm diameter, lesions of over 2 cm diameter were
differentiated. In the case of simple leucoplakia the laser ray of 5-6 W power
was applied, in nodular leucoplakia 6-10 W, and in verrucous leucoplakia the
power was 10-15 W. In this work the results of the 5 years observation are
presented.
PMID- 9757673
TI - [14 years of experience in using endoscopic laser microsurgery for various
laryngeal diseases].
AB - The author presented his own experience concerning the indication and limitation
of the method of laser CO2 application in endoscopic microsurgery based on 14
years experience in research on treatment of various larynx diseases at 2500
patients.
PMID- 9757674
TI - [Functional voice evaluation after Reinke's edema treated with CO2 laser and
Kleinsasser's microsurgery].
AB - The authors performed functional evaluation of voice in 124 patients treated with
microsurgery due to oedema Reincke in the years 1991-1994. In 90 patients surgery
was performed with CO2 laser microsurgery and in 34 patients with
microlaryngoscopy according to Kleinsasser. The picture of larynx was registered
and evaluated with help of laryngovideostroboscopy. The voice status was
evaluated in phoniatric examination, registered on tape and submitted to acoustic
analysis. No correlation between method of surgical treatment and quality of
voice was observed. However, significantly worse quality of voice was noted in
those smoking after surgery.
PMID- 9757675
TI - [Microsurgery of larynx in own material at the Otolaryngological Clinic of the
Central Clinical Hospital at the Military School of Medicine].
AB - In paper authors presented own material of performed in the years 1991-1996 in
Clinic of Otolaryngology Central Clinical Hospital Military School of Medicine
microsurgical operations of larynx (classic and laser). The authors postulate
that indications for clinical diagnostic and therapeutic procedures should be
considerably extended in diseases of larynx. This operating technique
considerably shorten hospitalization period of patients and significantly
contribute to an increase of percentage of early diagnoses of cancer of the
larynx.
PMID- 9757676
TI - [The use of the CO2 laser in the treatment of laryngostenosis and
tracheostenosis].
AB - The authors show the possibilities of using the laser CO2 in treatment of both
laryngostenosis and tracheostenosis in 54 patients. In the article various forms
of treatment of laryngostenosis and tracheostenosis as well as the results of the
therapy have been presented. On the basis of the cases treated so far, the
prospects of using the laser CO2 in this form of treatment have been found
limited. The best results have been attained in treating the narrowings on a
small surface. In case of complex laryngostenosis and tracheostenosis, the most
effective treatment has been obtained by using the combination of the laser
microsurgery performed on the larynx area along with the surgical resection of
the narrowed segment of the trachea and the fusion "end to end". In some cases
good results have been achieved by using the laser CO2 to remove postoperative
scars of the larynx after partial laryngectomies.
PMID- 9757677
TI - [Application of CO2 laser surgery in the treatment of rhinophyma].
AB - The authors present the method of combined treatment of rhinophyma (surgery and
laser CO2). The advantages of this method are good cosmetic result, small
intraoperating bleeding and short time of healing the wound.
PMID- 9757678
TI - [Laser surgery and interferon in the treatment of laryngeal papilloma].
AB - The laryngeal papilloma is very doubtful disease in children. The unknown
etiology cause that there wasn't complete radical method in the treatment of
laryngeal papilloma. Authors presented a case of 11 years old girl with recurrent
laryngeal papilloma, who was treated twice with laser microsurgery without
successful results. The 6 months application of interferon alfa after third laser
microsurgery resulted in more than one year of remission of the disease.
PMID- 9757679
TI - [Dacryocystorhinostomy by endonasal way].
PMID- 9757680
TI - [Endoscopic surgery of the sinus: own experiences].
AB - In the Clinic of Otolaryngology Central Clinical Hospital Military School of
Medicine in Warsaw in years 1992-1996 there were performed 187 endoscopic
operations of nose and paranasal sinuses. Authors analised own material paying
particular attention to indications, benefits and failures of these operations.
Authors postulate that indications for clinical diagnostic and therapeutic
procedures of this technique should be considerably extended in diseases of nose
and paranasal sinuses. The application of endoscopic sinus surgery in our Clinic
decreased the number of more extended operations of paranasal sinuses.
PMID- 9757681
TI - [Theoretical basis for the antibiotic therapy of the upper part of the
respiratory system].
AB - The paper presents the views on the etiology of infections in the respiratory
system. Beside the so called "old pathogens" such as Streptococcus pneumoniae,
Haenophilus influenzae, Moraxella catarrhalis, "atypic" microorganisms are
becoming more and more important, i.e. Mycoplasma pneumoniae, Legionella
pneumophila, Chlamydia pneumoniae. Mixed flora with aerobic and anaerobic
bacteria is observed in chronic infections. Viral infections facilitate bacterial
infections. Antibiotic used first should be active against the "old" and "new"
pathogens. Future prospects are set on macrolides such as clarythromycin.
PMID- 9757682
TI - [Zinnat in ambulatory treatment of acute pharyngitis and otitis media in adult
patients].
AB - The aim of this work was the assessment of therapeutic efficacy of antibiotic
Zinnat (Cefuroksym Aksetyl) in ambulatory treatment of acute pharyngitis and
otitis media in 20 adult patients, aged 21-36. The efficacy of Zinnat was
assessed on the basis of the smear from the throat and external auditory meatus
to examine the culture and antibiogram, fever chart and self-assessment chart of
symptoms which were assessed from 0 to 4. It was shown that Zinnat is an
effective antibiotic in ambulatory treatment of acute pharyngitis and otitis
media. It shows a wide range of antibacterial effect comprising most often
occurring pathogens bringing about acute pharyngitis and otitis media.
PMID- 9757683
TI - [The use of clarithromycin and amoxycillin in pediatric acute otitis media].
AB - We presented and compared Clarythromycin and Amoxycillin in the treatment of
pediatric acute otitis media. We evaluated in 2 groups ther clinical efficacy and
safety of Clarythromycin versus Amoxycillin.
PMID- 9757684
TI - [Diagnostic value of rapid streptococcal antigen test provided by Abbott "test
pack strep A": current report].
AB - The upper respiratory tract infections are the most frequent infectious diseases
in human. Beta haemolytic streptococcus group A is the most common etiologic
factor of bacterial pharyngitis. Delayed or inadequate treatment of streptococcal
pharyngitis can cause serious subsequent complications. Only a part of patients
show typical features of the disease so that the diagnosis can be based on
clinical appearance alone. For this reason we propose direct antigen test as a
rapid useful method which allows detection of group A streptococci in throat
swabs. The aim of the study is to estimate clinical value of rapid antigen test
in differential diagnosis of pharyngitis in children and adults. We have
performed 50 tests using commercial kit--Abbott Test Pack Strep A. Simultaneously
conventional bacterial throat cultures were performed. The comparison of results
acquired by both methods did not revealed any differences.
PMID- 9757685
TI - [Practical implications of bacterial resistance to antibiotics. Attempts to fight
it].
AB - Generation of strains resistant to antibiotics, its genetic mechanisms and the
role of incompetent administration of these drugs are presented in the paper. The
resistance is characterised mainly by the generation of extracellular enzymes
which cause the breakdown of beta-lactam ring Pathogenic bacteria which cause
changes in the respiratory system are discussed. The use of beta-lactam
antibiotics with beta-lactam inhibitors is a way to prevent generation of
resistant strains, the combination of amoxycillin and clavulanic acid is of
particular importance.
PMID- 9757686
TI - [Bacterial infections in otolaryngology on clinical material study].
AB - Bacterial species causing the hospital of the upper respiratory tract and ear
were analyzed in this study. Authors evaluated differences in the frequency of
various microorganisms on the clinical material. A special attention is paid to
the problems of anaerobial species. Microbiological analysis of the isolated
bacterial species and the assessment of their drugfastness was conducted.
PMID- 9757687
TI - [Bacterial flora in chronic purulent maxillary sinusitis].
AB - In the years from 1993 till 1995 there were 132 tests done on occurrence aerobes
(oxygen bacteria) and 56 tests on occurrence of anaerobes and fungus in patients
with chronic sinusitis. The most common microorganisms among the aerobes was
Haemophilus influenzae (23.1%) and Staphylococcus aureus (20.9%). The most common
microorganisms among the anaerobes was Peptococcus and Peptostreptococcus
(together 57.1%) and from the strains Bacteroides (36.8). The breeded oxygen
microorganisms Gr(+) were mostly sensible to clindamycin, cefuroxim and
augmentin; Gr(-) organisms to amicacin, gentamycin and cefuroxim. Anaerobes were
mostly sensible to metronidazole and clindamycin.
PMID- 9757688
TI - [Bacterial flora of the mouth cavity and pharynx and postop wound infection in
laryngeal cancer treatment].
AB - The study was carried out on 12 surgically treated patients with carcinoma
laryngis. Isolation and identification of oral cavity, pharynx, larynx and
postoperative neck wound microflora were performed. Failures in neck wounds
healing resulting from bacterial flora were compared. Sources of wound infection
were found due to biochemical features and antibiotics sensibility.
PMID- 9757689
TI - [Analysis of bacterial flora of the larynx: analysis of material collected in
1994-1996].
AB - This study reveals conclusions which source is analysis of 621 people with the
pharyngs diseases from 1994 to 1996.
PMID- 9757691
TI - [The study on biology of bacteriophages and their usage in the treatment of
bacterial diseases and on the influence of different bacteriophages on cytokine
production by leukocytes in human peripheral blood].
AB - The authors showed the examinations of the biology bacteriophages and using them
in the treatment of the bacteriology infection and influence difference
bacteriophages in producing cytokinins by leukocytes of human peripheral blood.
PMID- 9757690
TI - [Case reports of antibiotic complications].
AB - A case of 30 year old male with the severe course of generalised mycosis after a
few days antibiotic treatment. The diagnostics and procedure have been
considered.
PMID- 9757692
TI - [Rhinomanometry: a method of objective study of nasal patency].
AB - Rhinomanometry is the most applied method of evaluation of nasal patency in the
world. In the study the authors present application of rhinomanometry in the
diagnosis of the nose disease. On own material the authors introduce the
technique of rhinomanometry and interpretation of its results.
PMID- 9757693
TI - [Cell response in the nasal mucosa in patients with hay fever during plant pollen
season].
AB - The aim of the present study was to determine whether different reactions of the
nasal mucosa can be a result of a natural provocation with allergen. During the
pollen season of anemorphilous plants the nasal mucosa may trigger the following
reactions allergic inflammation or non-specific secretion.
PMID- 9757694
TI - [The evaluation of cellular immunity in patients with allergy to pollen].
AB - The study comprised 180 patients with pollinosis, 30 patients with vasomotor
rhinitis and 30 healthy male adults. The skin reactions of cellular immunity were
determined by Multitest CMI. The numbers of lymphocytes T and numbers of CD4 and
CD8 lymphocytes were determined under influence of histamine or clemastinum and
histamine or cimetidine and histamine. There were statistically significant
decrease of percentage of CD8 lymphocytes in patients with pollinosis after
addition of histamine. Statistically significant increase of percentage of CD8
lymphocytes after the addition of H2 receptor blocker indicated that blocking of
this receptor neutralized the effect of histamine on the CD8 lymphocytes. Author
observed increase of Multitest CMI skin reactions (particularly for antigens:
Streptococcus and Proteus mirabilis).
PMID- 9757695
TI - [Steroid therapy and surgical treatment of nasal polyps: cytological analysis].
AB - We have studies influence of steroids applied topically (intranasally) in
patients with polyps (both operated on and not operated) on the cytology of nasal
mucosa in conjunction with the level of serum ECP.
PMID- 9757696
TI - [The role of aeroallergens monitoring in the allergological practice].
AB - A physician wanting to help his hay fever patient efficiently needs to know the
causative agent in detail. High qualitative and quantitative variability in
certain years creates the necessity of constant pollen count monitoring.
Information on current trends is helpful to doctors in their diagnostic and
prophylactic procedures as well as in efficient treatment planning.
PMID- 9757697
TI - [The prophylaxis of allergic rhinitis].
AB - Authors present their own experience with prophylactic procedures applied in
allergic rhinitis.
PMID- 9757698
TI - [Perennial specific immunotherapy in pollen allergy].
AB - Authors present perennial immunotherapy procedure that they developed with
sublingal Perosall T 13 and Novo-Helisen Depot. The results of two-year
observation of 70 patients undergoing above mentioned therapy.
PMID- 9757699
TI - [The influence of antihistamine agents on reaction time].
AB - Authors carried out the study of reaction time on auditory stimulus in a group of
200 patients taking a single dose of: Clemastin, Phenazolinum, Zyrtec, Astemizol,
Claritin, Disophrol and placebo. The results indicate the prolongation of
reaction time after the administration of either first or second generation
antihistaminics.
PMID- 9757700
TI - [The effects of betahistine on the function of equilibrium system].
AB - The authors present a pilot investigation of the effect of betahistine on
vestibular disorders of peripheral and central origin. The evaluation of drug
efficacy was based on subjective symptoms (vertigo, dizziness) and values of
nystagmus parameters in ENG. and stability records made during posturographic
tests, before and after drug administration. The regression or moderation of
symptoms, such as vertigo and dizziness, was noted as well as the reduction of
nystagmus slow phase velocity and the amplitude and the reduction of parameters
during posturographic test. The reduction was observed during the treatment,
especially during the studies after 4 hours following drug administration. After
6 months, values of the parameters, especially those made during posturographic
tests, were close to initial values. The criteria, helpful for diagnosing
subjective ailments were discussed with the emphasis placed on the significance
of the processes responsible for equilibrium system function return. The review
was made of the literature concerning the role of betahistine in the treatment of
vestibular disorders.
PMID- 9757701
TI - [Registration of average potentials from neck muscles after the acoustic
stimulation of the vestibule in patients with impaired function of the internal
ear and in healthy subjects].
AB - Electrophysiological studies of human perceptive functions are displayed in last
years. The vestibular evolved myogenic potentials (VEMP) seems to represent a new
and promising technique for assessment of vestibulo-spinal reflex function. In
this study we have measured VEMP in patients with disturbed function of inner
ear. We have studied 6 patients with unilateral sensorineural deafness and normal
excitability of vestibular organs; 6 patients with unilateral weakness of
vestibular function and 19 healthy subjects. We have found that in patients with
unilateral weakness of estibular function VEMPs had diminished amplitudes whereas
in patients with unilateral deafness VEMPs were unchanged. These data strongly
suggest that VEMPs were generated by stimulation of vestibular end-organ. VEMPs
are highly objective, simple, secure and comfortable technique to assess the
vestibulo-spinal connections.
PMID- 9757702
TI - [Modified central otoneurological tests supported by computer analysis].
AB - The paper presents the results of the study of gaze-evoked nystagmus, direction
gaze nystagmus and optokinetic nystagmus in 193 subjects, including 85 healthy
pilots and 64 persons with vestibular pathology of central origin. For this
purpose, a computer program was applied for evoking strictly standardised
oculomotor stimuli. Moreover, computer analysis of the responses was introduced.
To make the method applicable for otoneurological evaluation of flying personnel
members, physiological norms of the parameters of interest for gaze-evoked and
optokinetic tests have been presented, based on the study results in different
age groups. Regardless the applied procedure, an initial analysis was made in
patients with vestibular pathology of central origin. After having compared these
results with the results achieved in healthy population, the introduced battery
of tests was found to be a reliable method of studies for the purpose of
otoneurological diagnostics.
PMID- 9757703
TI - [Methods of stimulation of otolithic tract: diagnostic possibilities, critique of
methods].
AB - Our modifications of the methods of otolith organs examination were reported. One
of these methods is eccentric rotation without the support of the body which was
held in two groups of the persons: control group of 32 healthy persons and 48
patients with unilateral vestibular loss. The second method of otolith organs
investigation was evaluation of them by producing dynamic optogravitational
reactions and measuring an angle of the eyeballs deviation and time of illusion.
Two groups--one consisting 102 healthy persons and second 91 persons with
unilateral hearing loss were examined. It was stated that the angle of eyeballs
deviation was reduced and time of illusion was longer in the group patients in
comparison with healthy person.
PMID- 9757704
TI - [The evaluation of the usefulness of electronystagmography studies in Doppler's
intracranial ultrasonography and brain stem evoked potentials in patients with
vertigo].
AB - The aim of the work was the evaluation of correlations between the
electronystagmographic results examinations and Doppler's intracranial
ultrasonography and brainstem auditory evoked potentials in patients with
vertigo. The were 68 patients tested (39 women and 29 men) aged 34-68 years. The
obtained results showed for the correlations between the electronystagmographic
results examinations and Doppler's intracranial ultrasonography and brainstem
auditory evoked potentials.
PMID- 9757705
TI - [Vertigo and vestibular disorders in patients treated from sudden deafness].
AB - In the article incidence of the vertigo and vestibular disorders in 119 patients
with sudden sensorineural deafness was evaluated. It was stated, that vertigo and
vestibular disorders had 47% of persons, abnormal trace in ENG examination--56%
of persons. Furthermore hearing recovery was less frequent in group of patients
with sudden deafness and vertigo than in group of patients without vertigo.
PMID- 9757706
TI - [Videonystagmography: a new diagnostic method in vertigo].
AB - We present videonystagmography a new method of vertigo diagnosis. The camera
record eye movement. We can obtain regostration of nystagmus in all directions.
Simplicity of use and great sensitiveness of to examinations are very important
two.
PMID- 9757707
TI - [A study of the phenomenon of voice intonation: analysis, usage and diagnosis].
AB - The aim of this work was to study the average rise time (RT) and average flow
rate (MRT) in utterance. Data were collected from 48 singers and 44 patients. The
group of patients included cases of modulus vocale, polypus laryngis, paresis
bilateralis, hemiparesis, and CA laryngis. Various characteristics of utterance
were recorded synchronously: the frequency and intensity of the fundamental
laryngeal tone were measured with a laryngophone, a microphone was used to
monitor acoustic radiation from the mouth, and a pneumotrachometer was applied
for the measurement of flow rate. The data were stored and analysed with the use
of a computer. Results show that the analysis carried out in the study describes
the distinctive characteristics of normal and pathologic utterance. The main
findings are as follows: a) rise time (RT) decreases with increasing loudness and
pitch of the sound and is also shorter in staccato than inlegato sounds; b)
during the initial transient of staccato sounds, the average flow rate in the
glottis increases with intensity and pitch of the sound; c) pre-fonation time
(TPP) and air volume do not differentiate normal and pathologic utterance; d) in
cases of voice pathology, the analysis of utterance described in this study can
be used for the evaluation of therapy and rehabilitation.
PMID- 9757709
TI - [Extrameatal myringoplasty in the treatment of tympanic membrane perforations].
AB - The clinical analysis of the patients after tympanic membrane reconstruction with
the temporal muscle fascia has been conducted. The total number of 145 patients,
operated at the Otosurgery Department Medical University of Lodz, was divided
into 2 Groups. Group 1 (n = 75) patients with chronic otitis media (central
perforation and mobile ossicular chain). The preoperative mean conductive hearing
deficit of 20 dB was observed in all evaluated patients. After surgery a
satisfactory hearing improvement was observed in 90% of the patients. Group 2 (n
= 70) patients with the reconstructed postero-superior part of the tympanic
membrance and if necessary external auditory canal wall reconstruction. The mean
conductive hearing deficit of up to 30 dB was observed before the surgery.
Postoperatively in 75% of patients the hearing improvement was observed as well
as the satisfactory healing of fascia implant. The postoperative evaluation
indicates a better hearing improvement after the myringoplasties with the
prefascial lamina than in the myringoplasties performed in the traditional ways.
PMID- 9757708
TI - [Audiological diagnosis in Military Medical Academy in Warsaw].
AB - Basis clinical proceeders in hearing loss diagnosis and the instruments used in
the Department of Otolaryngology of the Military Medical Academy in Warsaw were
presented.
PMID- 9757710
TI - [A case of objective tinnitus].
AB - The authors presented a case of objective tinnitus in patient with glomus tumor
suspicion. Tinnitus epidemiology, classification, causes and diagnostic procedure
were described. Any organic alterations, which would cause tinnitus, did not
find.
PMID- 9757711
TI - [Treatment results of acoustic trauma].
AB - 20 patients aged from 18 to 42 treated in the past few years because of acoustic
trauma. Together the investigations concerned 24 years. Therapeutic schema
comprised intravenous infusion--Sermion (Nicergoline--amp. a 4 mg) or Cavinton
(Vinpocetine--amp. a 10 mg) 1 amp.--twice a day for 10 days. The treatment of 60%
of the patients started in the first week after the trauma occurred, of 20% in
the second week and the remaining 20% later on after 15 days when the trauma took
place. The obtained results of treatment both of improvement of hearing (79.2%)
and tinnitus (66.6%), support the necessity of treatment of acoustic trauma
independently from the time that passed after trauma had occurred. Better results
of audiometric improvement of hearing (54.2%) and tinnitus disappearance (50%)
were obtained in the patients whose treatment started in the first week after
trauma. The improvement of hearing and tinnitus disappearance was more observed
in patients after treatment by using Sermion than Cavinton.
PMID- 9757712
TI - [A prognostic value of of stapedius reflex and accommodation coefficient in
patients with Bell's palsy].
AB - At 25 patients with Bell's palsy every 7 days stapedius reflex (SR),
accommodation coefficient as well as improvement of mimical facial movements were
examined. At 5 patients SR was noticed before treatment, at 13 after 14 days, at
4 after 21 and at 3 after 28 days since disease beginning. There was significant
correlation between return SR and improvement of mimical facial movements, but
there wasn't correlation between SR and accommodation coefficient.
PMID- 9757713
TI - [Results of surgical treatment of impaired nasal patency evaluated by
rhinomanometry and self-assessment by patients].
AB - 20 patients suffering from nasal potency disturbances were carefully clinically
(including self-assessment) and rhinomanometrically evaluated before and after
surgical treatment. Surgery brought sufficient improvement in nasal potency and
long term relief in clinical symptoms in most of the patients. Cases with only
temporal release were strictly analysed. We would like to emphasize the
importance to employ both surgery and accompanying conservative treatment to cure
these patients with significant functional contribution.
PMID- 9757715
TI - [Clinical application of magnetic pulsing fields in paranasal sinusitis
treatment].
AB - In this work were described advantages of the pulsating magnetic fields in
sinusitis treatment as independent and helping method.
PMID- 9757714
TI - [Pathological changes of frontal sinus in the materials of the Otolaryngological
Clinic of Medical Academy in Lodz (1986-1996)].
AB - Authors report 25 cases of frontal sinus diseases treated surgically at the ENT
Department Medical University of Lodz. There were three groups of pathologies: 13
cases of inflammatory disease, 9 osteoma cases and 3 trauma cases. The total
number of 30 surgical procedures has been performed (13 Beck's method, 6 radical
method, 6 classical method, 2 Ogston-Luc method and 3 reconstructions of anterior
wall of the frontal sinus using bone sutures). In each group the type of surgical
method and the causes of the possible postoperative pitfalls and recurrence of
the disease were analyzed.
PMID- 9757716
TI - [On keratomas on the frontal sinus].
AB - Etiopathogenesis of the frontal sinus kertomas has been discussed paying a
special attention to the frequency of its occurrence reported in literature.
Authors present a rare complication of frontal sinus keratoma involving a bone
destruction of nearby lying structures.
PMID- 9757717
TI - [A case of post-traumatic nasal hemorrhage stopped by externa carotid artery
ligation].
AB - A case of severe posttraumal epistaxis treated by external carotid artery
ligation is reported. This surgical procedure seems to be relatively simple and
highly effective in the management of refractory epistaxis.
PMID- 9757718
TI - [Clinical evaluation of Olbas oil effect on nasal mucosa in acute rhinitis
patients during common cold].
AB - The aim of the study was the clinical evaluation of the effect of Olbas oil on
nasal mucosa in patients with acute rhinitis during common cold. 15 patients with
2-3 days history of acute rhinitis during common cold, both sexes, in the age
between 23-47 were investigated. All the examinations were done before using,
after the first inhalation, and after 7 days of Olbas oil administration. The
investigation before using Olbas oil was comprised of: history data, general and
otorhinolaryngological examination with particular evaluation of nasal mucosa,
anterior rhinomanometry, saccharin translocation time, olfactometry,
microbiological cultures, histamine nasal provocation test. At the end, after 7
days of Olbas oil inhalation 3 times a day for 4 minutes 4 drops of Olbas oil
applied into a handkerchief, all the test were done again, as at the beginning.
The study showed a good of the effect of Olbas oil on nasal mucosa in patients
with acute rhinitis during common cold.
PMID- 9757719
TI - [The usage of nasal drops Tyzine in otorhinolaryngology].
AB - In this research the authors presented their experiences in the treatment of non
complicated and complicated acute mucous membranous rhinitis with application of
shrinking nasal drops Tyzine as a locally affective remedy assisting the therapy.
The aim of this research was the estimation of the efficiency of Tyzine drops
with mucous membranous rhinitis, their effect on the efficiency of the ciliary
transport and stating the probable side effects occurring after their
application. 80 persons were observed--60 adults who were treated with 0.1%
solution oftetrazoline hydrochloride and 20 children who were given 0.05%
solution. To state the condition of the ciliary transport within mucous membrane,
a saccharine test was conducted with all examined persons on the 1st and 5th-7th
days of treatment and on the 21st day after completing the therapy. The results
of the observation seem to be positive as for as the efficiency of nasal drops
Tyzine under the stipulation that the drops are reasonably applied and according
to the doctor's recommendation.
PMID- 9757720
TI - [Selected immunological studies of chronic purulent and hypertrophic
otolaryngological diseases].
AB - The aim of this work was the comparison of selected immunological parameters in
patients with chronic purulent and hypertrophic otorhinolaryngological diseases
who were to be operated on. The patients were divided into two groups: 1-31
patients aged 17-58 with chronic purulent otorhinolaryngological diseases. The
following immunological parameters were carried out: rheumatoid factor (RF),
immunoglobulins IgG, IgM, IgA, proteinogram including the level of albumin,
globulin alpha1, alpha2, beta and gamma. In chronic purulent
otorhinolaryngological diseases the characteristic features are the reduction of
the level of globulin alpha1 (67.7%) and gamma (35.5%), while in hypertrophic
cases globulin alpha1, and beta--91.7% each.
PMID- 9757721
TI - [A case of mucous cyst of the nasopharynx].
AB - We presented a rare case mucocele cyst of the nasopharynx in a 41 year old man.
The cyst was located at the higher level between the roof and right lateral band
of nasopharynx, and was removed by the transpalatal approach.
PMID- 9757722
TI - [Oxidase activity in patients with laryngeal carcinoma treated by radiotherapy].
AB - According to Ravin's method an oxidative activity of ceruloplasmin was determined
in the group of patients with carcinoma of larynx before and after rtg-therapy
and at the control group of healthy individuals. As a result of this assay the
significantly increased of oxidative activity ceruloplasmin was obtained in the
individuals with the carcinoma of the larynx before rtg-therapy in comparison to
the group of healthy subjects. Simultaneously a significant decrease of the
oxidative activity of serum ceruloplasmin in the individuals with carcinoma of
the larynx after rtg-therapy was observed.
PMID- 9757723
TI - [Trauma of the larynx and a method of treatment: case report].
AB - The authors presented the case of trauma of larynx after explosion of bullet. The
patient was treatment by use the special "T" tracheal cannula. That cannula fixed
the larynx supported free passage of superior respiratory tract and led to good
result of treatment.
PMID- 9757724
TI - [Endoscopic examination of esophagus performed by an otolaryngological head and
neck surgeon].
AB - The authors have analyzed 562 cases treated by esophagoscopy in ENT Department of
District Hospital Nr 1 in Rzeszow, Poland from 1987 to 1996. There have been 580
esophagoscopy performed during this period: In this number 504 therapeutic
procedures and 76 diagnostic ones. The most common indication for therapeutic
esophagoscopy has been the suspection or presence of foreign body in the
esophagus and rarely other pathology of upper part of digestive tract.
Complications of esophagoscopy are rather rare and in the most cases they are the
result of perforation of esophageal wall during esophagoscopy. In presented
material the complication rate was 0.17%. Impacted parts of false teeth in
esophagus should be always removed by experienced otolaryngologist under
endotracheal anesthesia and with esophageal muscles relaxation.
PMID- 9757725
TI - [The danger of removing some esophageal foreign bodies by fiber optics].
AB - The authors presented 4 cases of patients with a foreign body in the esophagus,
which has been tried to remove by means of fiberoscopy and rigid esophagoscopy.
The fiberoptic endoscopy has failed either as a diagnostic method or as a
therapeutic one. The classical esophagoscopy has turned out to be much better in
both cases. The fiberoscopy is a valuable diagnostic and therapeutic procedure in
a lot of diseases of digestive tract. Especially it is useful in order to remove
some foreign bodies from the esophagus, but at the same time it fails when
removing big foreign bodies (e.g. parts of false teeth, large bones). In these
cases rigid esophagoscopy is the only effective method when performed under
endotracheal anesthesia and with esophageal muscles relaxation.
PMID- 9757727
TI - [The evaluation of granulocyte function before and after surgical treatment in
patients with chronic inflammation of the middle ear and palatine tonsils].
AB - The aim examinations was the evaluation of granulocytes (PMNL) pre- and
postsurgical treatment in patients with chronic inflammation of middle ear and
palatine tonsils. The examined 40 persons and divided into three groups: I--18
patients with chronic inflammation of middle ear, II--10 ones with chronic
tonsillitis and III--12 healthy persons. There were evaluated: "in vivo" and "in
vitro" migration, bactericidal index and absorption of S. aureus labeled 14C
isotope (phagocytic index) in the own modification. Preoperative treatment in
patients with chronic inflammation of middle ear and palatine tonsils in
comparison to the healthy were noticed: characteristic increase of the migration
area, the MIF liberation and the phagocytic index, decrease in the bactericidal
index (but more in group II). After a year postsurgical treatment the function of
granulocytes in patients of group II was more similar to the healthy than in
group I.
PMID- 9757726
TI - [The case of purulent epiglottitis complicated by the cervical and mediastinum
phlegmon with septic shock].
AB - The authors showed the case of purulent epiglotitis complicated the neck and
mediastine phlegmone with septic shock.
PMID- 9757728
TI - [Clinical studies of Olbas oil tolerance and its effect on nasal mucosa in
healthy volunteers].
AB - The aim of the study was the clinical examinations of the tolerance and effect of
Olbas oil on nasal mucosa in healthy volunteers during permanent 4 weeks
administration. 23 healthy volunteers both sexes in the age between 20-50 were
investigated. This investigations consisted of: history data, general and
otorhinolaryngological examination, with particular evaluation of nasal mucosa,
anterior rhinomanometry, olfactometry, saccharin translocation time,
microbiological cultures, histamine nasal provocation test. Besides, each patient
has follow up self evaluating chart of symptoms and adverse effect from the eyes,
nose, pharynx and others. All the examined persons showed a very good tolerance
of Olbas oil after 28 days of inhalation.
PMID- 9757729
TI - Female genital mutilation: some ethical questions.
AB - This paper provides some basic information about female genital mutilation (FGM)
as a social problem and as a health problem. It includes selected actions taken
over the last 45 years by the United Nations regarding FGM. The focus here is on
the ethics of individuals and institutions, such as the World Health
Organization, attempting to intervene in traditional cultural practices like FGM.
This discussion raises some questions about ethical universals and ethical
relativism with regards to FGM and the attempts to change or eradicate this
practice.
PMID- 9757730
TI - Hobson's choice: reproductive choices for women with learning disabilities.
AB - This paper examines the present law in England and Wales concerning the
sterilisation of women who are unable to give valid consent to medical treatment.
In particular, it considers why sterilisation is frequently presented as the only
meaningful reproductive choice that can be made by or on behalf of women with
learning disabilities. In addition, the paper assesses the extent to which the
best interests test, as formulated by the English courts, has been successful in
the promotion of dignity and autonomy of women with learning disabilities. It is
submitted that some of the issues presented to the courts have not received
adequate consideration and others have been considered which are not relevant to
the determination of the best interests of these patients. Furthermore, the best
interests of the adult patient are determined by reference to the 'Bolam' test.
This paper questions whether the Bolam test is the appropriate mechanism for
determining the patient's best interests, having particular regard to the
Australian model of decision-making for the intellectually impaired.
PMID- 9757731
TI - Contracting and the purchaser-provider split in western Europe a legal
organizational analysis.
AB - Market forces have been introduced in the health care systems of many European
countries. Fundamental to the introduction of the market was the need to
distinguish between the roles of purchaser and provider. In this article the
authors have analyzed the consequences of contracting and the purchaser-provider
split from both a legal and organizational perspective. Using a modification of
an existing theoretical framework for analyzing the basic health care models,
contracting and the purchaser-provider split in some Western European countries
has been analyzed. Including the legal and organizational dimension into these
economically oriented models, these models can also be used for analyzing recent
trends and developments. A four-country analysis indicates trends towards
convergence of health care systems and both decentralization and integration in
the systems. The future roles of both managers and lawyers working in health care
need to be further defined.
PMID- 9757732
TI - Islamic jurisprudence and the end of human life.
AB - Death is an inevitable reality but the causes leading to death may vary from
individual to individual. In the past, death was considered to be a simple and
straightforward phenomenon. The general practitioner would issue the death
certificate once he was convinced that there was cessation or absence of
spontaneous life in the patient. This meant that the patient had stopped
breathing, his heart had stopped beating, there was unresponsiveness, his body
had turned cold and finally rigor mortis had set in. With the successful
accomplishment of heart transplants, it became obvious that a process of
rethinking on how death could be determined had to be instituted. Cessation of
heartbeat is no longer considered evidence of death since the heart is now able
to be substituted with that of a just-deceased donor or with that of a baboon or
even with a mechanical one. Moreover, modern biomedical innovations like the
resuscitator and cardiac pacemaker have made it imperative to establish a set of
criteria by which the moment of death could be identified. Diagnosis of brainstem
death is relevant to the issue of retrieving viable vital organs, i.e. heart,
lung, liver and kidney, for transplantation purposes. The Holy Qur'an emphasizes
the universality of death and from its teachings one gathers that the moment of
death would be at the time when the soul is separated from the body. However, one
has to concede that the Qur'an does not in any way tell us anything about the
nature of the soul nor of its location in the human body, hence the dilemma of
Muslims insofar as brain death is concerned. In this paper, an attempt is made to
analyse the deliberations of the classical and contemporary Muslim scholars on
the end of human life with the aim of determining whether brain stem death could
in effect be regarded by Muslims as the end of human life and if not why?
PMID- 9757733
TI - HIV/AIDS and human rights in prison. The Costa Rican experience.
AB - HIV and AIDS issues deal directly with Human Rights and Public Health. Four basic
principles have been acknowledged internationally in connection with HIV/AIDS:
Autonomy, confidentiality, right to health and non-discrimination. According to
these principles, it is not possible to adopt illegal or unethical measures
toward HIV- infected persons. However, these may rarely be necessary in the case
of prisoners, taking into account the possibilities of unpredictable behavior,
violence and use of drugs, which are common in prisons. The World Health
Organization as well as the United Nations have established the possibility of
taking measures, different from those outside the jail, that may be illegal but
necessary in order to protect the human rights of inmates, the general prison
population and the security of the penitentiary system. Therefore coercive
measures such as isolation may be imposed upon an inmate infected by HIV when he
or she deliberately may try to infect others. This paper examines different types
of situations dealing with HIV/AIDS in prison and reviews the international
recommendations and the way the Costa Rican legal and penitentiary system have
adopted them in accordance with its legal system and national prison
characteristics.
PMID- 9757734
TI - Protection of patients' rights in Estonia.
PMID- 9757736
TI - Evaluation of the new legislation on psychiatric compulsory care in Sweden.
AB - In 1992 the Compulsory Mental Act from 1966 was replaced by two enactments. The
purpose was to restrict the use of compulsory care and coersive measures, to
strengthen the legal safeguards for the patients, and to increase the protection
of society. A follow-up and evaluation of the reform has been performed by the
National Board. This paper will present details of the results. The main
impression was that the laws function fairly well. However, the National Board
proposed some changes in the new acts. The government has started a parliamentary
group to consider these suggestions.
PMID- 9757735
TI - Brain trauma: cause-consequence connection problems.
AB - Despite sophisticated equipment like computerized tomography, in some cases
doctors have a problem with the diagnostic procedure in relation to patients with
serious injuries of the central nervous system (CNS). There may be no clinical
signs of disorders of the CNS, or other evidence of difficulties, but diffuse
axonal lesions and demyelinisation processes often exist. This type of lesion is
a special pathomorphological entity, known as the syndrome of patient who talks
and dies. Macroscopical and microscopical findings are poor and rare, especially
in the hours immediately following the injury. The main findings are not
evidential and the problem is the explanation of sudden death from unknown
causes. The following studies are based on human tissue analyses. They are based
on the analyses of the CNS of patients who suffered from brain trauma. The
specimens from the brain stem were taken in order to perform histological,
microscopic analysis. Percentage value of surface of myelin for the control group
was X1 38.62% for HE technique and X1 33.46% for Gomory's method. The value for
the test group was X2 16.12% for HE technique and X2 13% for Gomory's technique.
Statistical probability for both groups was 95% (P < 0.05; T = 14.9). Application
of these procedures helps legal authorities to make trials more objective.
PMID- 9757737
TI - Medical negligence and post traumatic stress disorder (PTSD).
AB - Post traumatic stress disorder (PTSD) is well recognised as a consequence of
natural and man-made disasters, accidents and assaults. An increasing number of
plaintiffs making claims for compensation alleging medical negligence complain of
the symptoms of PTSD. Medical accidents such as anaesthetic awareness and
stillbirths may be claimed as stressors and relatives may allege PTSD as a
psychological injury following witnessing the death or suffering of a loved one.
A series of cases will be presented. Many cases are entirely genuine but
increasing media publicity has alerted potential plaintiffs and their legal
advisers to the symptoms of PTSD which make evaluation of symptoms difficult for
psychiatric experts. Psychometric tests exist to screen PTSD but research has
shown that they can be falsified and it would be unwise to rely on such tests.
PMID- 9757738
TI - A study of substance abuse on two campuses of University of Papua New Guinea.
AB - BACKGROUND: Recent research reports indicate that there is a substantial amount
of substance abuse on the campuses of the University of Papua New Guinea.
OBJECTIVE: To compare the frequency and quantity of alcohol and drug abuse on the
two campuses of the University of Papua New Guinea in the National Capital
District. METHODS: A purposely designed questionnaire was used to collect data
randomly on a total of 90 subjects (45 from each campus). The data was subjected
to computer analysis. RESULTS: The results show that abuse of alcohol, tobacco
and other drugs is prevalent on the two campuses of the University of Papua New
Guinea. CONCLUSION: The results will form the basis of recommendations for
substance abuse prevention, through information and education of the University
students and staff members.
PMID- 9757739
TI - Informed consent to medical treatment--the Israeli experience.
AB - The ideological foundation of the doctrine of "informed consent" is rooted in the
concept of personal freedom and freedom of choice. The concept of individual
autonomy is represented by the "reasonable patient" standard which requires the
disclosure of all information which a reasonable person in the position of the
patient would need in order to make a rational decision regarding a proposed
medical treatment. This attitude, however, conflicts with the traditional
paternalism which is reflected in the "reasonable physician" standard, that is
that a doctor must disclose that medical information which a rational doctor
would relate to a patient in order to receive his consent. The enactment of the
Patients' Rights Law in Israel in 1996 was an essential turning point in Israeli
medical law. Section 13 of the new law explicitly establishes the requirement of
informed consent and the details which a doctor must relate to a patient in order
to reach the said agreement. Nevertheless, the law does not state the standard
according to which it should be assessed whether the disclosure was proper. In a
recent decision (C.A. 434/94 Shai Berman et al. v. Mor--the Institute for Medical
Information, Ltd.) the Israeli Supreme Court took a step forward and determined
that the duty to inform a patient will be judged by recognised criteria of
negligence as they apply to the merits of each case.
PMID- 9757740
TI - Video technology and children's evidence: international perspectives and recent
research.
AB - Research has shown that children can be as competent and reliable as adults as
eyewitnesses of crime, if questioned in an appropriate manner. However, there is
considerable variation between, and within, countries in the way in which child
witness evidence is accepted in criminal cases. This article reviews the legal
facilities that exist for young witnesses in countries such as the United States,
England & Wales, Canada and Australia. Particular emphasis is placed on recent
research into the use of video technology by the courts in child abuse cases-
namely testimony with a live video link or a pre-recorded interview in place of
live, open court evidence. Studies into the use of live link and videotaped
interviews have shown that these innovations could help to reduce the trauma of
testifying for children and could lead to better quality evidence from the child.
However, there is considerable concern among legal and child protection
professionals about the relative lack of impact of video testimony when compared
with live, in-court testimony. Research has uncovered significant support among
legal professionals towards using curtained partitions 'screens' to allow a child
witness to testify within the courtroom without allowing the child to see, or be
distracted by, the accused. There is also widespread concern about the
questioning techniques used in videotaped interviews and with the live link.
Future implications for the use of video testimony are also discussed.
PMID- 9757741
TI - Forensic medicine, its tasks and duties in medical malpractice and medico-legal
litigation.
AB - Forensic medicine assists in clarification of cases of violent death, assessment
of bodily damage and indemnity, especially in cases of work injuries, it also
deals with deaths that occur within two hours of a doctor's intervention. As
"legal medicine", forensic medicine is taught both to medical students and to
students of the juridical faculties. In cases of medical malpractice, forensic
pathologists give opinions in courts. Cases of alleged malpractice are handled
differently in different countries. Establishment of expert committees in the
Czech Republic represents a reasonable solution to this problem. Activities of
the committees are described.
PMID- 9757742
TI - Medical research and informational privacy.
AB - This paper focuses on the processing of medical data for scientific research and
the protection of privacy. Attention will be given to the collection, storage and
use of medical data for research. First, the international framework, as provided
by the Council of Europe's Convention for the protection of individuals with
regard to automatic processing of personal data--and Recommendation No. R (83) 10
on the protection of personal data used for scientific research and statistics,
and Draft Recommendation on the protection of medical data, based on this
Convention--and the European Directive on the protection of individuals with
regard to the processing of personal data and on the free movement of such data,
will be described in broad outlines. Within this international context, the
relevant Dutch laws, that is to say the Law on Registration of Personal Data and
the Medical Contract Act, will be discussed. The paper concludes with some
remarks on the (Dutch) Code of Conduct on Health Care Research.
PMID- 9757743
TI - Money, medicine, and Methuselah.
PMID- 9757744
TI - New concepts in the pathogenesis and treatment of allergic asthma.
AB - This review delineates the currently accepted, multifaceted approach to the care
of an asthmatic patient. Therapy is based on our improved understanding of the
pathophysiology of this complex disease, in which IgE and mediators derived from
many cells contribute to airway inflammation. The latest trends in therapy
involve the institution of anti-inflammatory medications relatively early in
disease. With the recent availability of a novel class of therapies, the
leukotriene antagonists, and other therapies based on antagonism of adhesion
molecules, cytokines, chemokines, or IgE itself, the future may provide
additional alternatives for the physician treating patients with asthma.
PMID- 9757745
TI - Current events and bioethical concerns in physician-assisted death.
AB - In June 1997, the Supreme Court of the United States found that the Constitution
does not guarantee a right to physician-assisted suicide, thereby allowing states
the opportunity to variously prohibit or permit such practice. The Court's
findings notwithstanding, physician-assisted death remains a topic of intense
medical, legal and philosophical discussion. Principled discourse variously
supports both an ethical prohibition against assisted death and an ethical
obligation to help some patients achieve death. Both theoretical and practical
concerns are raised by the practice of physician-assisted death. This essay
reviews recent events and developments concerning assisted suicide and
euthanasia. The discussion which follows was generated by the members of the
Committee on Bioethical Issues of the Medical Society of the State of New York
and builds upon a previous Committee report.
PMID- 9757746
TI - Anesthesia for nonobstetric surgery during pregnancy.
AB - Approximately 50,000 pregnant women undergo nonobstetric surgery each year in the
United States. Administering anesthesia during such surgery is one of the only
situations in which anesthesia impacts on more than one individual (mother and
fetus) at the same time. Providing a safe anesthetic to the pregnant woman
requires an understanding of the physiologic changes of pregnancy and the impact
of anesthesia and surgery on the developing fetus. The following review will
consider the risks of the mother and to the fetus during nonobstetric surgery.
PMID- 9757747
TI - Concepts of preemptive analgesia for postoperative pain.
AB - BACKGROUND: The predictable relationship between surgical injury responses and
the ensuring postoperative pain has led to the development of the concept of
preemptive analgesia, with its potential to improve the quality of the
postoperative period. METHODS: A review of publications concerning the studies of
the physiology of pain and the development of clinical strategies toward the
prevention of postoperative pain was undertaken. RESULTS: Clinical studies using
various methodologies indicate that preemptive analgesia may, in some
circumstances, attenuate postoperative pain. Unfortunately, these studies were
not always reproducible. Preemptive analgesia in these studies failed to prevent
or attenuate postoperative pain. CONCLUSION: Techniques directed toward reducing
and/or eliminating postoperative pain are still being developed, and their
clinical utility is yet to be fully evaluated.
PMID- 9757748
TI - Multiple cerebral infarction in Japanese breath-hold divers: two case reports.
AB - We report on two Japanese breath-hold divers (ama) who developed neurological
disturbances following more than 3 hours of consecutive dives to 15-25 meters of
seawater. Their magnetic resonance images of the brain showed multiple cerebral
infarcts which were consistent with their neurological symptoms. The cerebral
lesions seem to have been caused by repetitive breath-hold dives for extended
periods of time. Immediate recompression is required when neurological symptoms
develop after such dives.
PMID- 9757750
TI - Complications of subcutaneous injection ports.
AB - Subcutaneous injection ports have become widely used for patients who require
prolonged central venous access. Complications of their placement and use are
well documented in the existing literature. We report two previously undocumented
complications occurring in Port-a-Cath units, and suggest methods to lessen the
likelihood of recurrence of these problems.
PMID- 9757749
TI - Severe hyponatremia, neuroleptic malignant syndrome, rhabdomyolysis and acute
renal failure: a case report.
AB - Acute renal failure secondary to myoglobinuria is a rare yet possible
complication of malignant neuroleptic syndrome associated with the use of
dopamine antagonists. We describe the case of a 42-year-old schizophrenic man who
presented with severe hyponatremia, and proceeded to acute malignant neuroleptic
syndrome, rhabdomyolysis, and acute renal failure. We contend that the acute
hyponatremia may have served as a precipitating factor.
PMID- 9757751
TI - Gynandroblastoma in pregnancy: case report and review of literature.
AB - Gynandroblastoma is an extremely rare tumor, composed of sex cord and stromal
cells of both ovarian (granulosa-theca) and testicular (Sertoli-Leydig) types. We
believe that its occurrence during pregnancy has not been previously reported.
The patient was a 32-year-old woman who during her pregnancy was noted to have a
progressively enlarging, unilocular left ovarian cyst. Beginning at 18 weeks
gestation, the fetus required multiple platelet transfusions for severe
alloimmune thrombocytopenia. A viable baby girl was delivered by cesarean section
at 39 weeks gestation. At that time, an ovarian cystectomy also was performed.
When the histology of the tissue subsequently became known, a left salpingo
oophorectomy was performed for gynandroblastoma. One year later, at the time of
laparoscopic sterilization, the examination of the pelvis was normal.
PMID- 9757753
TI - The Libby Zion case revisited: what have we learned?
PMID- 9757752
TI - Impact of the Libby Zion case on graduate medical education in internal medicine.
AB - Residency training in New York State was substantially altered by the Libby Zion
case. Work-hour limitations and augmented supervisory requirements changed the
patterns of training--particularly in internal medicine--but with uncertain
impacts on the quality of education and patient care. In this historical
analysis, we review another major effect of the case: a substantial augmentation
of the number of trainees. The need to maintain adequate inpatient staffing-
within the ground rules of the Residency Review Committee, and in consideration
of the reimbursement formulae and financial climate of New York State--conspired
to promote substantial residency program expansion. Similar forces contributed to
a national trend to increase the number of trainees. The history, cost and impact
of these personnel changes are reviewed.
PMID- 9757754
TI - Unexpected factors predict control of hypertension in a hospital-based homeless
clinic.
AB - BACKGROUND: Boston Health Care for the Homeless Program (BHCHP) physicians
conduct a primary care clinic twice a week at Massachusetts General Hospital
(MGH). The MGH clinic is part of a city-wide network of BHCHP clinics providing
primary care services to indigent patients. Despite this network, long term
control of chronic illnesses such as hypertension (HTN) continues to challenge
the clinic staff. METHODS: In an effort to better understand the factors
obstructing long term treatment of chronic illness, we conducted a chart review
of hypertensive patients seen over a three-year period (January 1991 to March
1994) at the MGH clinic. Frequency of visits, total number of visits and
physicians' notes on concomitant diagnoses were analyzed for their correlation to
control of hypertension. RESULTS: Overall control of hypertension was poor (42%).
A greater proportion of patients with a diagnosis of psychiatric illness
responded to treatment intended to lower their blood pressure below 140/90 mm Hg
than those without such a diagnosis (odds ratio: 10.2). While there was no
difference in the total number of clinic visits during the study period, those
with a diagnosis of psychiatric illness had a lower average number of days
between their first and third visits (52 days vs 108 p = 0.002). CONCLUSIONS: A
greater proportion of patients with concomitant psychiatric diagnoses exhibited
blood pressures < or = 140/90 mm Hg than patients without mental illness. The
increased frequency of visits at the onset of treatment may confer a positive
effect on long term control of HTN among homeless patients attending outpatient
hospital-based clinics.
PMID- 9757755
TI - Generalized morphea.
PMID- 9757756
TI - [Construction and its characteristic on the concept of a 'health culture'].
AB - Toward the 21st century, subjects and methods of hygiene and public health will
be specialized and subdivided. However, practical approaches to human health need
an integrated method focusing to a structure of human life. Under these
circumstances, the concept of 'health culture' becomes prevalent. The role of
hygiene related to the improvement of life style, the development of re-cycle
system, and fulfillment of a barrier-free system focussed on the handicapped and
the elderly have become increasingly important. Therefore, an increase in the
recognition to the concept of 'health culture' is essential to the research of
hygiene. The purpose of this paper is to make a historical and theoretical
analysis of health culture', in order to promote it as the leading concept of all
activities concerned with health in the 21st century. The methods of this paper
are mainly historical and theoretical review. 'Health culture' was introduced in
American and European societies a hundred years ago. Health culture in the USA
involves knowledge and skills applied to actual daily life, refrecting pragmatism
as the ideal feature of American society. In Germany, the concept of 'Hygienishe
Kultur' was established at the field of social hygiene by Grotjahn and by Fischer
in the early 20th century. This concept recognized the importance of the
development of culture and independence of life in labour based on the evolution
of the concept of 'Hygienishe Kultur'. In Japan, under the influence of German
social hygiene, the social hygienic theory flourished. A social hygienist, Tetsuo
Hoshino used the term 'hygienic culture' in the context of life creation toward a
healthy life. Health culture is the total system concerning knowledge,
experience, skill, and norms related to health, which has developed with the
development of society. It has fundamental function promotes the creation of
culture and self-cultivation of living man, whereas, it contributes to the
realization of health based on individuality, in conjunction with the co
operation of medical and health sciences. The contemporary representation of
health culture includes new health care activities such as self-care, a self-help
movement, and health volunteer activities. It means the basic shift of the
function of health culture is from that of life style to life movement. Nowadays,
the role of hygiene in the total health care system is seriously considered. The
goal, objects, and methods of hygiene should be re-evaluated under the concept of
'health culture', in order to re-define hygiene as the science for people living
in a society.
PMID- 9757757
TI - [The relationship between stress and health indicators in an urban population-
from a study of subjects selected by sex and age groups who underwent health
check-ups in S city in Osaka Prefecture].
AB - Many people in recent years are living under conditions involving various kinds
of major and minor stress. This study was done to analyze how an urban population
experience stress in daily life and to establish any relationship between the
feeling of stress and people's daily habits or health conditions. The subjects
were 2,234 residents, who availed themselves of general health check-ups in a
city in Osaka Prefecture in 1992. The main results were as follows: 1) We
designed and assessed a total stress score for causes of stress in daily life and
a total depression score for the depression condition of subjects. 2) The
proportion of subjects who showed a high total stress score decreased with age.
The proportion of subjects who showed the highest total stress score was the
largest in the age group of 40-49 years for men and of 30-39 years for women. 3)
The proportion of subjects who had short working hours, much leisure time
available, and low total depression score and complained much about health
conditions increased with age. The proportion of subjects who had the longest
working hours was the largest in the age group of 30-39, that of those who had
little leisure time available and showed the highest total depression score was
the largest in the age group of 40-49, and that of those who complained most
about health conditions was the largest in the age group of 60-69 for men. The
proportion of subjects who had the shortest sleeping hours and the longest
working hours was the largest in the age group of 40-49, that of those who had
little leisure time was the largest in the age group of 30-39, and that of those
who showed the highest total depression score was the largest in the age group of
30-39 and 50-59 for women. 4) The total stress score showed significant
relationships with the amount of leisure time available, the degree of complaints
about health condition, and the total depression score for men and with sleeping
hours, the amount of leisure time available, the degree of complaints about
health condition and the total depression score for women. 5) The total stress
score showed a significant correlation with high blood pressure for men and
women. 6) The amount of leisure time available showed significant relationships
with sleeping hours for men and working hours for men and women. The total
depression score showed significant relationships with the degree of complaints
of health condition for men and with sleeping and working hours, the amount of
leisure time available and the degree of complaints of health condition for
women.
PMID- 9757758
TI - [Flow cytometric analysis of the effects of 50 Hz magnetic fields on mouse
spermatogenesis].
AB - The cellular effects of an extremely-low-frequency (ELF) magnetic field on mouse
spermatogenesis were assessed by DNA flow cytometry and serum testosterone. Seven
week old male ICR mice were exposed to a 50 Hz magnetic field the strength of
which was 1.0 m Tesla. Seven mice per treatment group were exposed for 13, 26, 39
or 52 days. For each experimental point, an equal number of mice per sham-treated
group were used as a control and were exposed only to the background field below
1 mu Tesla in the same room as the treatment group. In the control mice, the
testis cellular DNA content distribution by flow cytometory was characterized by
four quantifiable populations; round spermatids (1C), spermatogonia and other
diploid cells (2C), spermatogonial cells synthesizing DNA (S-phase) and primary
spermatocytes (4C). In animals exposed for 26 days the number of cells in the 4C
and the 4C:2C ratio was significantly lower, and the 1C:4C ratio (meiotic
transformation) was significantly higher than the corresponding control groups.
In animals exposed for 52 days the cell population in 1C and the 1C:2C ratio
(total germ-cell transformation) was significantly higher, and the cell
population in 2C was significantly lower than the corresponding control groups.
The concentration of serum testosterone in animals exposed for 13 days was
significantly higher than in the corresponding control group. These changes
suggest that long-term exposure to an ELF magnetic field had a possible effect on
the proliferation and differentiation of spermatogonia.
PMID- 9757759
TI - [The presentation level of interrupted pure tone for inducing the pulse
phenomenon of continuous white noise].
AB - When two sounds which have same spectrum but different amplitude are alternated
without silent gap between the sounds, the lower amplitude sound comes to be
heard as continuous. This is called "auditory induction" which is one of the most
interesting auditory phenomena. The fainter sound is called induce and the louder
sound is called inducer. The authors previously reported that the addition of
interrupted pure tone to continuous white noise induced the pulsed noise. This
pulse phenomenon was thought to be a kind of auditory induction; the inducer is
the noise image of white noise with the silent part of interrupted pure tone and
the induce is the noise image of white noise with the pure tone part of
interrupted pure tone. The authors hypothesized that an auditory filter made with
the pure tone of interrupted pure tone generates the two noise images in the
continuous white noise. Present experiments were made to investigate the change
of "the threshold of interrupted pure tone for inducing the pulse phenomenon"
(TIP) when the presentation level of continuous white noise and the frequency of
interrupted pure tone are changed. TIP was constant and independent of both the
amplitude of continuous white noise and the frequency of interrupted pure tone.
All subjects reported that the higher the frequency of interrupted pure tone is,
the harder it becomes to hear the pulsed noise image. It is supposed that this
phenomenon does not contradict the theory of the auditory filter.
PMID- 9757760
TI - [Effects of acute endurance exercise and 8 week training on the production of
reactive oxygen species from neutrophils in untrained men].
AB - We investigated the effects of acute endurance exercise and habitual physical
activity for health maintenance on human neutrophil function in 12 untrained men.
The acute exercise condition was a continuous exercise for 90 minutes at the
intensity of 50% and 55% of maximal oxygen uptake (VO2max) on an ergometer. The
training program was 3 km jogging three times per week for 8 weeks. The capacity
of neutrophils to produce reactive oxygen species (ROS) was detected with
lucigenin-dependent chemiluminescence (LgCL) and luminol-dependent
chemiluminescence (LmCL) on stimulation with opsonized zymosan (OZ) and phorbol
myristate acetate (PMA). As for the acute exercise effects, both LgCL and LmCL
responses of neutrophils, stimulated using PMA consistently increased after
exercise at 50%VO2max, whereas those stimulated with OZ remained unchanged. At
55%VO2max, LgCL responses to both stimulants increase maximally 1 h after
exercise, and then decreased 3 h after exercise, whereas LmCL responses to both
stimulants increased continuously after exercise at 55%VO2max. These phenomena
observed at 55%VO2max compared to 50%VO2max suggests the improved capacity of
producing ROS neutrophils after exercise. The number of neutrophils also
increased maximally 1 h after exercise, due to the mobilization of band
neutrophils (shift to the left), suggesting that functional changes was
associated with cell mobilization. The increase in the capacity of neutrophils to
produce ROS and marked neutrophilia following the acute endurance exercise
suggests that a large quantity of ROS may be produced in vivo. As for the
training effects, the LgCL and LmCL responses were maintained in the exercise
group as compared to the decreased ones in the control group. The difference
between the exercise group and the control group was observed only in LgCL
response to OZ. Humoral immune factors (IgG, IgA, IgM, C3, C4) and serum opsonic
activity were also unaltered. These phenomena suggest that homeostasis might be
kept constant in terms of immunity through regular physical activity.
PMID- 9757761
TI - [The effects of improved diets on the daily intake of environmental contaminants
as calculated from personal food consumption data, by Monte Carlo simulation].
AB - In a previous paper, we discussed the Estimated Ecological Daily Intake (EEDI),
which is a new method for the estimating daily intake of environmental
contaminants based on individual food consumption data. This method makes it
possible to identify high-risk cases, using a Monte Carlo simulation for varying
contamination levels in each food item and permits epidemiological assessment of
the individual, rather than the population, intake of environmental contaminants.
We attempted to identify those contaminants whose maximum dietary levels were
most commonly exceeded. The results obtained were as follows: 1) After a 1,000
fold extrapolation, performed for each person and contaminant, some cases
exceeded allowable maximums in dieldrin, lead, cadmium, and total mercury. In
dieldrin and lead intake, few cases exceeded dieldrin and lead maximums by a
factor of 2 or 3, but in the cases of cadmium and total mercury, individual
maximum intake was significantly exceeded. 2) After estimating a high-risk
individual's times of exceeding the allowance in cadmium intake with dietary
improvement, we found a 10.5% excess intake after 40% improvement. Clearly, the
issue of environmental contaminants exposure due to dietary intake is a
significant one.
PMID- 9757762
TI - [The development of the Japanese version of the Maslach Burnout Inventory and the
examination of the factor structure].
AB - This article presents an evaluation of the factor structures of the Japanese
version of the Maslach Burnout Inventory (MBI). The MBI is a widely used
psychometric instrument for measuring 'burnout' developed by Maslach and her co
workers. The MBI consists of four subscales: Emotional Exhaustion, Personal
Accomplishment, Depersonalization, and Involvement. The MBI was translated into
Japanese along with a back-translation and was administered to a sample of 267
nurses. Various psychometric analyses showed that the Japanese version of the MBI
has high reliability for the 22 items scored for the frequency dimension. The
factor analysis using principal factoring with an oblique rotation resulted in
three factor structures that had different implications from the MBI: Emotional
Exhaustion/Depersonalization, Personal Accomplishment, and Physical Exhaustion.
The correlationship between the MBI and the General Health Questionnaire (GHQ),
measures of depression, showed that burnout was a unique phenomenon.
PMID- 9757764
TI - [The effects of fluid ingestion and its composition on uric acid metabolism
during high intensity long term exercise].
AB - The purpose of this study was to analyze the effects of fluid ingestion and its
composition on uric acid metabolism after exercise. Six healthy males volunteered
for the study which was comprised of three different experiments; Exp. 1, Exp. 2,
and Exp. 3. In all the experiments, subjects performed treadmill exercise
(70%VO2max) for 70 minutes respectively. For seven hours after exercise, subjects
ingested mineral water at 10 degrees C ad-lib in Exp. 1, 1.5 times the volume of
mineral water consumed in the first experiment in Exp. 2, and the same volume of
sports drink as in the first experiment in Exp. 3. No significant differences
were observed in oxygen uptake and heart rate during exercise among the three
experiments, so it was considered that the produced serum uric acid (SUA) levels
in the three experiments were about the same level. However, the decrease in SUA,
urinary uric acid excretion (UUA), clearance of uric acid (CUA) and fractional
excretion of uric acid (FEUA) in Exp. 3, in which the sports drink was consumed
instead of mineral water were higher than in Exp. 1 and Exp. 2. On the other
hand, no significant differences were found in Exp. 2 and Exp. 3. A significant
relationship between UUA and FEUA was found among the three experiments, while
there was no corrleation between UUA and urine volume. These results show that;
1) the sports drink ingestion can increase the efficiency of recovery from high
serum uric acid after exercise, 2) the increase in uric volume due to high
mineral water intake does not elevate UUA, and 3) the increase in UUA due to
sports drink ingestion was associated with the increase of FEUA.
PMID- 9757763
TI - [NK cell activity and subsets of truck drivers along with related factors].
AB - We investigated the immunity and the main factors that affect the immune system
of 19 truck drivers as the experimental group and 27 office workers as the
control group at a transit corporation in Tokyo; all subjects in both groups were
examined through an assay of NK activity and NK subsets before and after work. At
the same time, they were asked to complete a questionnaire on their working hours
per day (WHPD) and driving hours per day (DHPD), in addition to the Health
Practice Index (HPI), Self-Rating Depression Scale (SDS), Stress Tolerance Check
List (STCL), and Symptom Checklist (SCL). The results obtained were as follows:
1. Before work, no difference was seen in NK activity between the experimental
group and the control group, with both groups showing E:T ratios 5:1 to 20:1.
After work, the NK activity (E:T = 20:1) of the experimental group was
significantly lower than that of the control group. 2. In the experimental group,
the NK activity and NK subsets (CD3-CD16+CD56+, CD3-CD56+, CD3-CD16+) of the
peripheral blood lymphocytes after work were significantly lower than before work
(p < 0.05, p < 0.01, p < 0.01). After more than five driving hours, the value of
the CD3-CD16+CD56+ subset was significantly lower than that after fewer driving
hours. 3. Correlation coefficients were calculated based on the average value of
NK activity (E:T = 20:1), CD3-CD16+CD56+ subset, and WHPD, DHPD, and HPI in the
driving group. NK activity (E:T = 20:1) and DHPD were found to be negatively
correlated (r = -0.28), as were the CD3-CD16+CD56+ subset and WHPD (r = -0.43)
and the CD3-CD16+CD56+ subset and DHPD (r = -0.63). On the other hand, NK
activity (E:T = 20:1), the CD3-CD16+CD56+ subset and HPI were found to be
positively correlated (r = 0.41 and 0.33).
PMID- 9757765
TI - [An analysis on a relationship between perinatal mortality and live births of low
birthweight, in Kumamoto Prefecture, 1968-1994].
AB - The aims of this investigation were to describe the relationship between
perinatal mortality rates and the proportions of live births among low birth
weight (LBW) infants from 1968 to 1994, and to determine risk factors in infants
of low birth weight. Using vital statistics from 1968 to 1994 of the Japanese
government and the Kumamoto Prefecture and Maternal and Child Health Statistics
of Japan from 1968 to 1995, perinatal deaths and live births of infants of low
birth weight were studied according to national statistics criteria. In Japanese
and Kumamoto Prefecture, there was an association between perinatal deaths and
live births of LBW. The significant decline of perinatal mortality rates from
1968 to 1976, of which the fetal death ratio at 28 weeks and over mostly
declined, was closely related to the decline of live births of LBW. In this
period, the improvement of socioeconomic conditions and the comprehensive health
care provided by the government contributed in improving perinatal mortality
rates. From 1977 to 1988, the annual variation of Kumamoto was different from
that of all Japan. Both perinatal mortality rates continued to decline due to a
general decrease in early neonatal mortality rates. The number of Live births of
LBW infants in Kumamoto prefecture increased in 1977 and once again started to
decline in 1982. In 1977, the insufficient maternal-child health care and the
increase of female workers contributed to increasing rates of live births of LBW.
Advances in neonatal medicine contributed to the increase in survival rates of
infants of LBW. Although, after 1982, the improvement of maternal-child health
care and the perinatal care system contributed to the declining rates of live
births of LBW. On the other hand, those rates in all Japan continued to gradually
increase from 1977 to 1988. After 1989, perinatal mortality rates continued to
decline, and live births of LBW continued to increase in both Kumamoto prefecture
and all Japan. These results were contrary to the above results from 1968 to
1976. It was considered that medical advances in the care of pregnant women and
neonates increased survival rates of the LBW. In future, the perinatal mortality
rates will appear to approach a minimum constant, that is, a minimum of fetal
death rates. It is important to reduce the number of LBW infants, particularly
birthweight of 2000 g-2499 g, with maternal-child health care.
PMID- 9757766
TI - [Study of skin temperature, microclimate and comfort of clothing of old females
at rest--ambient temperature x humidity: 30 degrees C. R.H.80%, 30 degrees C.
R.H.45%, 20 degrees C. R.H.45%].
AB - Old females are compared to young females for the purpose of studying the
difference in comfort caused by the environmental variables of temperature and
humidity as well as the form of clothing. Eight experiments were performed in
three settings: (a) 30 degrees C R.H.80%; 30 degrees C R.H.45%; and 20 degrees C
R.H.45%. The ages of the subjects range from 62 to 68 (Mean = 65.17, S.D. = 1.68)
among old females and from 20 to 23 (Mean = 20.83, S.D. = 0.76) among young
females. The following results were obtained: (1) The young females were
sensitive to hot temperatures, while the old females were not. On the other hand,
the old females were more sensitive to cold temperatures, under 20 degrees C
R.H.45%, than the young females. In temperatures under 30 degrees C R.H.80%, the
heat radiation from the young females was higher than that of the old females.
Under 20 degrees C R.H.45%, the heat radiation from the old females was higher
than from the young females. The old females are thought to decline in
physiogenic function due to enduring both hot and cold temperatures. (2) The
correlation between the temperature in clothes and comfort among the old females
is not different from the same correlation among the young females. This
conclusion agrees with previously published studies of the young females. (3)
Skin temperature and bloodstream are measured, according to clothing form. As a
result, a long skirt is the highest in thermal insulation, long pants the next
highest, and a short skirt is the lowest. (4) The effect of thermal insulation
provided by a lap robe was tested in both groups. The lap robe was found to be
more effective for the older group than the younger in temperatures under 20
degrees C R.H.45%. Hence, the role of clothes in offsetting for the decline in
the thermoregulation function that compensates for environmental change is more
important for old females than for young.
PMID- 9757767
TI - [A viewpoint of the revision of the prevention law of infectious diseases].
PMID- 9757768
TI - [Study of the validity of ADL assessment by Minsei-iin of bed ridden elderly
cared for at home].
AB - We studied the validity of assessment of activities of daily living (ADL) by
minsei-iins of the bed ridden elderly cared for at home. The cases, 66 male and
128 female elderly in a county of Gunma Prefecture, had been registered by minsei
iins (non-professional district welfare commissioners) as bed ridden cared for at
home. Minsei-iins interviewed the case and the caregiver at home, asking them
about the term of care, the levels of independence in their daily living, and
seven items of ADL. Out of the 194 cases registered, PTs or OTs interviewed 136
cases, 42 male and 94 female, and calculated the Barthel index score. The
Quantification method of the first type was applied to the data to predict the
Barthel index score. The independent variables were five items of ADL assessed by
the minsei-iins. The relation was close between the assessment of all items of
ADL by the minsei-iins and the Barthel index calculated by the PTs or OTs. The
Quantification method of the first type revealed that bathing, excreting and
walking contributed most to the measured Barthel index. The multiple correlation
coefficient was 0.687. There were three cases who scored 100 in the Barthel
index.
PMID- 9757770
TI - [A survey of allergic diseases among elementary school children in Saga
Prefecture. The first report. Prevalence and past history].
AB - This study was carried out to determine the prevalence of several allergic
diseases among elementary school children in Saga prefecture. A questionnaire was
distributed to the parents of 2,795 children in 12 elementary schools located in
urban, seaside and mountainous areas. The response rate was 92.8%. The prevalence
rate of allergic diseases among school children was 24.6% (24.5% for boys and
21.5% for girls). The common types of allergic diseases among boys were allergic
rhinitis (11.3%), atopic dermatitis (9.7%), and bronchial asthma (5.7%), and
those among girls were atopic dermatitis (9.7%); allergic rhinitis (6.5%), and
bronchial asthma (3.7%). Analysis by residential area of the children, showed
that the prevalence rate of allergic diseases in total was increased in the order
of mountainous (20.8%), seaside (24.1%) and urban area (28.7%). The most common
type of allergic diseases was atopic dermatitis in urban and mountainous area,
while allergic rhinitis was most common in seaside area.
PMID- 9757769
TI - [Relation between passive smoking at home and dietary intake].
AB - To investigate confounding factors in the relation of passive smoking to
diseases, we compared the dietary intake of passive smokers, non-smokers without
passive smoke exposure, and smokers. The subjects were female respondents to a
baseline survey, which was conducted as part of a collaborative cohort study in a
rural area. Of the subjects, 101 females were smokers. A total of 1978 female non
smokers answered the question about passive smoking exposure at home, including
1,392 (70.4%) passive smokers and 586 (29.6%) non-passive smokers. Among these
three groups, the dietary intake of 36 foods (frequency and amount) was compared
by odds ratios calculated with a logistic regression model. The percentages of
subjects reporting frequent intake of milk or milk products, carrot or pumpkin,
tomatoes, oranges, and fruits except oranges, were significantly lower in passive
smokers than in non-passive smokers (OR = 0.80, 0.74, 0.80, 0.77, 0.79). On the
other hand, more subjects in passive smokers reported frequent or large intake of
pork, salt pickled vegetables, soy sauce pickled foods, soft drinks, coffee, and
moso soup (OR = 1.38, 1.53, 1.32, 1.73, 1.30, 1.33). The dietary pattern of
passive smokers was similar to that of smokers. In conclusion, in this study,
passive smokers had different dietary patterns from non-passive smokers'. In
future research regarding disease with passive smoking exposure, dietary factors
should be considered as a confounder.
PMID- 9757772
TI - [Study on blood glucose control of subjects with borderline type abnormality in
75 G oral glucose tolerance test values. The establishment of a high risk group
on the basis of yearly observations].
AB - SUBJECTS AND METHODS: 227 of subjects with a 2-hour plasma glucose concentration
of 120-199 mg/dl were selected from 413 participants who had two or more 75 g
OGTT in health examinations from 1987-1995. From these subjects we established 8
groups according to initial 2-hour plasma glucose concentration 120-199 mg/dl
stratified by 10 mg/dl, and calculated the total percentages of participants
whose 2-hour plasma glucose concentration reached 200 mg/dl or greater over a 1-8
years (2.7 +/- 1.7 years, mean +/- SD) observation period. In 36 subjects who
were tested annually over a four year period (4 times), the mean values of their
4 values were analyzed for relationships to coefficients of variation of the 2
hour plasma glucose. RESULTS: By stratified groups (from lowest to highest) of
those with an initial plasma glucose concentration of 120-159 mg/dl, 7.4%, 12.1%,
16.1%, and 15.0% attained values of 200 mg/dl and higher, respectively in 1-8
years. On the other hand, 29.6%, 29.6%, 39.1%, and 47.4% of those with an initial
plasma glucose concentration of 160-199 mg/dl moved to a diabetic type after 1-8
years, respectively. The percentages of those who ended up with levels of 200
mg/dl and greater at 2-hours tended to increase in subjects whose initial 2-hour
plasma glucose concentration was over 160 mg/dl in comparison with patients below
that initial level. CONCLUSIONS: From these results, it appears that subjects
with 160-199 mg/dl 2-hour glucose concentration, which is considered a borderline
status, are at high risk for future abnormal levels (> 200 mg/dl at 2-hours) and
should be managed as a high risk level group for prevention of diabetes.
PMID- 9757771
TI - [Relationship between dietary fiber intake and food intake patterns of the
general population, evaluated by a regional nutrition survey].
AB - This study was performed to estimate the dietary fiber intake calculated using
individual food intake data and the dietary fiber tables, and to ascertain the
relationship between food intake patterns and dietary fiber intake of the general
population. The 805 subjects over 15 years old were obtained from the Tottori
Prefecture Nutrition Survey. The results are summarized as follows: 1. The
average dietary fiber intake per capita per day was 18.19 g; 18.67 g in men, and
17.81 g in women. Dietary fiber intake per energy was different among sexes and
ages: women had more dietary fiber than men and the aged had more than the young.
Those who had high fiber intake per energy took green vegetables, fruits, milk,
soybean products, seaweed and potatoes more frequently, and did not take oil so
frequently. 2. Total dietary fiber intake from 20 food-group sources was analyzed
by Multiple Regression Analysis. For both men and women fruits, vegetables and
soybean products mostly influenced dietary fiber intake. 3. Based on the intake
of the 20 food-groups obtained from 356 men and 449 women, the correlation matrix
among these foods was calculated. The correlation matrix was also submitted to a
Principal Component Analysis. The result of the Principal Component Analysis told
that food intake patterns were different among the levels of dietary fiber
intake. Food intake patterns of men and women who had high fiber intake per
energy had an eating pattern characterized by relatively more non-processed
vegetable food, bread and milk. 4. The level of blood pressure was significantly
related to dietary fiber intake per energy in men over 60 years old. In the
hypertensive men over 60 years old, 23.3% were in the low fiber intake group,
37.2% in the middle group, and 39.5% in the high group. But in the normal blood
pressure men over 60 years old, 50.0% were in the low fiber intake group, 8.3% in
the middle group, and 41.7% in the high group.
PMID- 9757773
TI - [Characteristics of home care patients with intractable neurological diseases
(Nanbyo) in Tokyo].
AB - The purpose of this study was to identify the characteristics of home care of
patients with intractable neurological diseases. A survey was conducted of
members of Tokyo Medical Association who were home visit doctors. They responded
to questions about their patients who have suffered from either Parkinson's
disease (PD), spinocerebellar degeneration (SCD), or amyotrophic lateral
sclerosis (ALS), and whose home care have been supported by the care system for
at least three months. Of 205 survey questionnaires collected, 198 were effective
to be analyzed. The sample consisted of 105 patients with PD (53.0%), 63 patients
with SCD (31.8%), and 30 patients with ALS (15.2%). The mean age of the PD was
75.5 years with a range of 53 to 90, SCD was 66.5 years with a range of 39 to 88,
and ALS was 58.7 years with a range of 42 to 86. The major findings in this study
were as follows: 1) The patients who had one or more medical equipment installed
at the beginning of home care were 30% of ALS, 9% of PD and 18% of SCD. As time
elapsed, patients who needed to have some medical equipment installed increased
in ALS greater than in PD and SCD. 2) The home doctors predicted that the
condition of 37% of ALS patients, 9% of PD, and 8% of SCD would probably be
deteriorating within one month. 3) Of the 30 patients with ALS, 47% experienced
hospitalization three times or more compared to 27% of PD and 21% of SCD. The
most prevalent reason for hospitalization for ALS was respite of caregivers, PD
and SCD, however, were hospitalized for control of prescription, a change for the
worse, or treatment of other diseases. 4) Ninety percent of ALS caregivers felt
extremely tired or slightly tired. Their home doctors responded that 83% of ALS
caregivers did their best in caregiving. 5) ALS patients utilized social
resources such as volunteers, care workers, services of supply and maintenance of
medical equipment, and emergency care for 24 hours more than SCD and PD. In the
conclusion, ALS patients experienced the highest hospitalization of the three
diseases and respite of family caregivers was necessary. They showed a higher
utilization of various social resources than other diseases. It is important to
consider these characteristics of home care patients by diseases in order to
prepare and develop the necessary support system of home care for the intractable
neurological patients.
PMID- 9757774
TI - [The health and welfare system for elderly in France].
AB - Dichotomy is the main characteristic of the Health and Welfare system in France.
This system lies on two distinct fields, the medical field which is managed by
the National Government, and the social field managed by the Local Government.
The French home care policy for the elderly has developed a large number of
services to assist in activities of daily living, to provide nursing and medical
care at home, to improve living conditions, to maintain social relationships, and
to postpone institutionalization and hospitalization, respectively. The main home
care service is represented by "home helpers" who provide maid Notiniralics
services. The second widely used service is the "home care service" performed by
a team of nurses, assistant-nurses, psychologists, physiotherapists. This team
provides nursing care and assistance in activities of daily living. As for
institutions for the elderly, they are divided into welfare and medical
institutions. The welfare institutions include social establishments like shelter
homes and nursing homes. The medical institutions are mostly represented by long
term care hospitals. One of the main goals of the aging policy is to create
medical wards in welfare institutions in response to the increased dependency of
the institutionalized elderly. Recent experimental and innovative concepts have
been established, such as "shelter homes for dependent elderly" for physically or
cognitively impaired elderly.
PMID- 9757775
TI - [Inflammation of the pelvis minor].
AB - Pelvic inflammatory disease (PID) is the must important gynecologic infectious
disease. It causes not only serious clinical symptoms, life threatening
complications, but also severe damage to the female upper reproductive tract.
Among its important sequale are infertility due to tubal occlusion, ectopic
pregnancy, dyspareunia, and chronic pelvic pain. The must important causative
organisms are Neisseria gonorrhoeae, Chlamydia trachomatis, as well as anaerobic
and facultative bacteria found in the vaginal flora of women with bacterial
vaginosis. The author reviews the latest developments regarding the epidemiology,
etiology diagnostics, medical and surgical therapy of the disease. The importance
and possibilities of prevention are discussed.
PMID- 9757777
TI - [A new technic in the management of hydrocephalus: neuro-endoscopy].
AB - Conventional valve shunting for treatment of hydrocephalus has a high rate of
long-term complication. After a brief historical review of neurosurgical
endoscopy the authors present the different indications and methods of
neuroendoscopy. Between 1995 and 1997 twenty-two pediatric patients underwent
endoscopic surgery at National Institute of Neurosurgery. Twelve of them had
third ventriculo-cistemostomy, and cystic wall fenestration was performed in ten
children. All but one patient benefited from this minimally invasive endoscopic
technic. Minor transient complications were seen in three cases, and only one
patient had long-term pupillary dilatation due to the surgical procedure.
PMID- 9757776
TI - [Current status of the management of upper gastrointestinal hemorrhage at a
specialized hospital unit].
AB - The prevalence of bleeding of the gastrointestinal tract is around 100/100,000
adults/year. These events need special diagnostic and therapeutic approach, which
previously was located mostly to surgical departments. At the beginning of 1996 a
specialized ward ("gastrointestinal bleeding unit, GBU") was created at the 2nd
Dept. Medicine of the University Medical School of Debrecen. The authors give an
account about their experiences with the first 250 cases, try to establish the
optimal and necessary conditions and analyse the consequences of their newly
developed "risk-score" system. The overall mortality was 9% during this period
and surgical intervention proved to be necessary in only 10 cases. On the basis
of the collected experiences, they are convinced that the described and
elaborated model can well be used for the proper, up-to-date management of
gasrointestinal bleeding disorders. As next they suggest an overall, regional
organisation of such units, together with the correct determination and provision
of the financial background.
PMID- 9757778
TI - [Bcl-2 expression in testicular cancer in relation to tumor progression].
AB - Bcl-2 expression has been studied extensively in a variety of human tumors.
However, there are lack of clinical data in regard to its expression in germ cell
testicular tumors (GCTTs). In this study we screened bcl-2 expression in 70
patient with GCTTs using the immunohistochemistry (IHC) and streptavidin biotin
alkaline phosphatase method. Furthermore, we correlated this expression with
metastatic behaviour and clinical stage. Overall, 41 (58%) carcinomas stained
with anti-bcl-2 (DAKO-124) monoclonal antibody, By histologic type, these lesions
included 11 (42.3%) of 26 seminomas (S) and 30 (68.18%) of 44 non seminomatous
germ cell testicular tumors (NSGCT). The incidence of bcl-2 immunostaining was
higher (P = 0.05, two-tailed, Fisher's test) in NSGCT than in seminomas. Bcl-2
expression was higher in tumors from metastatic patients than in tumors from
metastatic-free patient (p = 0). There was a significant difference between the
three stages of disease as to the expression of bcl-2 (chi 2 = 0). High level of
bcl-2 was clearly dominant in tumors of advanced stages. The present finding
revealed that bcl-2 expression occurs in GCTTs. Further, they suggested that bcl
2 is associated with a more progressed malignant phenotype in these tumors.
PMID- 9757779
TI - [Renal candidiasis following treatment of infantile osteomyelitis].
AB - Systemic candidiasis with renal complications is a rather rare phenomenon in
young infants. Authors report on a 4.5 month-old baby (preterm) who, during an
antibiotic therapy of wide spectrum--because of osteomyelitis--acquired a mycotic
infection causing bilateral pyelon and pyeloureteral obstruction. In addition to
systemic antimycotic therapy surgical intervention was needed to eliminate the
mycotic bezoar.
PMID- 9757780
TI - [300th anniversary of the birth of Bernhard Siegfried Albinus, reformer of
anatomy].
PMID- 9757781
TI - [Diagnostic value of cutaneous manifestation].
PMID- 9757782
TI - [Newest contraceptive agents].
PMID- 9757783
TI - [The evaluation of breed-specific defects in dog breeds from an animal welfare
viewpoint].
AB - Issues of breed defects such as morphology, physiology or behaviour in pure-breed
dogs, are briefly discussed. Suggestions for various kinds of improvements are
made, particularly concerning legislation, analysis of pedigree to avoid
undesirable breed characteristics and what breeding clubs, individual breeders,
judges, future dog owners and veterinarians could and should do about these
problems; these are followed by summary conclusions.
PMID- 9757784
TI - [Classical swine fever in 1993 in Switzerland: molecular-epidemiologic
characterization of the virus isolate].
AB - RT-PCR followed by direct nucleotide sequencing of the amplified cDNA was carried
out to analyse most of the 5' nontranslated region (5'NTR) of classical swine
fever virus (CSFV) isolates from the five 1993 disease outbreaks in Switzerland.
Sequence data were compared to other CSFV strains, and dendrograms were
constructed in order to determine the phylogenetic relationship of the Swiss
virus strains. Dendrograms formed by the analysis of different parts of the 5'NTR
were compared. It was shown that all Swiss isolates were related to other CSFV
strains involved in disease outbreaks in Europe in the 1990s. Two of the isolates
were indistinguishable from a CSFV strain isolated from wild boar meat imported
from China into Austria in 1993. The risk of introducing classical swine fever by
improperly treated swill and, in particular by importing wild boar meat is
discussed.
PMID- 9757785
TI - [The diagnosis of patellar luxation in small animals].
AB - A standard diagnostic procedure for patellar luxation is described. It is based
upon the patellar luxations grade 1 to 4, which have been published before, and
contains additional definitions in terms of the animals positioning toward the
examiner.
PMID- 9757786
TI - [Case presentation in small animal medicine].
AB - A 11 year old female spayed Jack Russel Terrier was diagnosed with diabetes
mellitus and ketoacidosis. After successful initial treatment metabolic control
deteriorated although insulin dosage was increased. Cushing's syndrome was
diagnosed and treatment with Lysodren was started. As a result blood glucose
concentrations decreased. The difficulty to diagnose Cushing's syndrome in some
diabetic dogs is discussed.
PMID- 9757787
TI - [Morphology and molecular biology of malignant soft tissue sarcomas].
AB - Malignant soft tissue tumors are classified and named according to cellular
differentiation and thus the non-neoplastic soft tissue they imitate. The topical
WHO classification already comprises more than 140 entities and tumor subtypes,
but the process of defining new tumor variants will go on. Questions of
nomenclature are discussed briefly with laying special emphasis on the non
undisputed concept of malignant fibrous histiocytomas. Without doubt, this
diagnosis is made too frequently by which it has become to a collective name for
unclassifiable pleomorphic sarcomas. For the time being nobody is able to say
whether or not the malignant fibrous histiocytoma will remain an entity. Likely,
fibrosarcomas and hemangiopericytomas are defined as exclusion diagnosis, as
well. The diagnosis of malignant soft tissue tumors is based on recognizing the
cellular line of differentiation. This is frequently possible at light
microscopic level, sometimes additional diagnostic methods are required. The most
important adjunct method is immunohistochemistry. Because aberrant
differentiations and unexpected immunohistochemical reactions are known the use
of a panel of antibodies is necessary. In the last years soft tissue tumors has
increasingly been characterized by molecular biological methods. The results are
of significance for understanding sarcoma pathogenesis and may be used for
diagnosis, as well. Chromosome translocations are explained and rhabdomyosarcomas
are taken as example for demonstrating the diagnostic significance of molecular
biological/cytogenetic findings. Molecular biology may also aid in defining the
histopathologic features of an entity as shown for intraabdominal desmoplastic
small cell tumors. Eventually, heterogeneity in soft tissue sarcomas is addressed
and discussed in view of its importance for diagnosis, classification and therapy
as well as for development of sarcoma progression.
PMID- 9757788
TI - [Surgical aspects in the multidisciplinary treatment of soft tissue sarcomas].
AB - Sarcomas are rare malignant tumors with a large variety of histologic subtypes.
The surgical approach depends more on the histologic grade, the size and the site
of the tumor. Radiologic diagnosis relies predominantly on MR-imaging.
Discernible improvements have taken place in soft tissue sarcoma patient
survivorship and quality of life over the past 20 years, with overall 5-year
survival currently at approximately 50-80%. The place of surgery in the treatment
of soft-tissue sarcoma is defined in the light of a review of the recent
literature. Radical surgical resection is the mainstay of therapy. Local
recurrence is the most common type of failure. Local recurrence is resectable and
limb preservations possible in the majority of patients. Survival after treatment
of local recurrence is determined mainly by the grade and secondarily by the size
of the tumor. The essential risk factor for local recurrence is the quality of
surgical resection, defined by the definitive resection margins. A lateral safety
margin of 5 cm and of 2 cm to the depth should be respected. In sarcoma of the
extremity the compartment is defined based on clinical, radiographic,
histopathologic and operative findings. The use of muscle flaps to fill the
surgical defects can improve the functional result and reduce the complication
rate. Only about 5% of the patients need amputation. Evaluation of functional
results must be based on objective criteria. In retroperitoneal sarcoma the
significant factors for determining prognosis are grade and completeness of
exzision. Multidisciplinary treatment according to common protocols is essential.
Shifts in treatment have taken place over the past decade, from single-modality
treatment involving radical surgery with compartment resection to sophisticated
limb-salvage strategies combined with radiation therapy. In case of inadequate
surgery e.g. in a large tumor with positive margins in high-grade soft tissue
sarcomas the addition of radiotherapy can improve local control, but cannot
ensure that obtained by adequate surgery. Patients with large (greater than 5
cm), high grade soft tissue sarcoma are at high risk for distant recurrence and
disease-related mortality. Investigations of combined modality therapy with newer
chemotherapy agents and dose intensification treatment strategies are warranted.
PMID- 9757789
TI - [Surgical management of soft tissue sarcomas: principles of resection and
reconstructive plastic procedures].
AB - 1. Adequate complete surgical resection with a oncologic radical or wide margin
of normal tissue represents the most important measure to prevent a local
recurrence. Limited excision with "shelling-out" of the tumor, through its
"pseudocapsule" almost invariably means positive microscopic margins. The
pathohistologically or macroscopically marginal or intralesional positive
resection margins make a salvage surgery necessary. 2. A close safety margin of <
1 cm due to neighboured anatomic structures indicates a high risk of local
recurrence and makes an adjuvant radiotherapy mandatory. Plastic-reconstructive
surgery should prepare the radiotherapy fields, to avoid cavities or ulcerations.
3. Facts should be stated in the clinical record and the operation report, e.g.
the safety margin should be defined by the surgeon and the pathologist; the
histopathologic stage and grade are absolutely basic requirements. If necessary,
a second histopathologic review should be asked for. 4. Tumor resection and
reconstructive oncoplastic measures should correspond individually to the
oncologic parameters, to the functional demands and to the age of the patient. 5.
Multidisciplinary cooperation in a tumorboard is a precondition for an adequate
treatment.
PMID- 9757790
TI - [Adjuvant chemotherapy in early soft tissue sarcoma and palliative chemotherapy
in advanced soft tissue sarcoma in adults].
AB - Adjuvant chemotherapy (chth): The place of postoperative adjuvant chth after
complete resection of a primary tumor (R0) is not well established. 13 adjuvant
chemotherapy trials with a variety of combinations and most often doxorubicin
alone in different regimens were compared to a control group without
chemotherapy. Only 2 reports showed a difference in overall survival and 4 some
gain in disease-free survival. New studies began with defined inclusion criteria
and a control arm without chemotherapy. There are only some risk factors coming
into consideration: deep seated tumors with histologic grade 2 and all grade 3
cases. Adjuvant chemotherapy appears justified only within these studies. The
potential side effects of adjuvant chemotherapy outside of these trials are
detrimental (e.g. 10% cumulative risk of cardiomyopathy after ADM; risk of
secondary leukemias) and a benefit is not known. Primary induction chth:
Preoperative neoadjuvant chth has to be reserved for studies. They are performed
in case of deep seated large primary tumors, not suitable for R0-resection
without mutilation. Palliative Chth: In metastatic or locally not curative
resectable disease treatment is palliative. The aim of treatment is the relief of
existing symptoms or the avoidance of threatening complaints and possibly
prolongation of life. The combination of ADM and Ifosfamide (IFO) is commonly
used although its superiority to ADM monotherapy is not proven. As second line
chemotherapy in case of tumor resistance high dose IFO-monotherapy can be put up
for discussion. Myeloablative high-dose-poly-chth with stem cell transplantation
remains an experimental approach.
PMID- 9757791
TI - [Radiotherapy of soft tissue sarcomas].
AB - Soft tissue sarcomas are uncommon neoplasms that represent approximately 1% of
all malignancies. It is clear that sarcomas require a therapeutic approach that
establishes local control and thereby eliminates the potential of metastasis for
patients with truly limited disease. Localized sarcomas are generally treated by
surgery. Excision must be complete, with a wide margin of normal tissue, and
along anatomic planes, or recurrence will almost certainly follow. Amputations
are still occasionally required, although limb salvage procedures are being used
increasingly, particularly in the context of multimodality therapy with
irradiation or chemotherapy. Radiotherapy can be highly effective for improving
local control and is used as adjuvant therapy, either preoperatively or
postoperatively. In case of non-in-sano-resection a salvage surgery is indicated.
Use of adjuvant postoperative radiotherapy allows for more conservative surgery
without compromising local control, and therefore often may allow limb salvage
where amputation might otherwise be necessary, e.g. in case of R1- or R2
resection without a new resection, a close margin or large tumors with histologic
G2 or G3 grading and in case of local relapses. Local control rate of 90% are
reported for the combination of pre- and postoperative radiotherapy. Prognosis is
still limited by distant metastases. In case of unresectable tumors neutron
radiotherapy results in 50% local control. New approaches e.g. hyperfractionated
accelerated radiotherapy, interoperative radiotherapy and chemoradiotherapy are
promising perspectives, which are being evaluated in clinical studies. Desmoid
tumors benefit of postoperative radiotherapy in case of R1-resection or relapse.
PMID- 9757792
TI - A community medicine project involving an educational session in sexually
transmitted diseases for high school students.
AB - The University of South Dakota School of Medicine requires that students
undertake a Community Medicine project of their choice as part of the Family
Medicine course in the third year of medical school. One of these projects
consisted of a presentation given to a high school class in Sioux Falls, South
Dakota, on sexually transmitted diseases. The effectiveness of the presentation
in increasing the students' knowledge on this subject was measured by a pretest
and posttest multiple choice examination. The students' knowledge was clearly
increased by the presentation.
PMID- 9757793
TI - Newer-generation fluoroquinolone antibiotics.
PMID- 9757794
TI - A medical student's experience in Venezuela.
PMID- 9757795
TI - [The ever-present future].
PMID- 9757796
TI - [Endovascular treatment of abdominal aortic aneurysm. Preliminary experiences
with the Talent endoprosthesis].
AB - BACKGROUND: The treatment of infra-renal abdominal aortic aneurysms (AAA) with
endovascular stent-graft prostheses is receiving increasing attention as an
alternative to major abdominal surgery. Numerous systems are under clinical
investigations. We report our preliminary clinical results with the new Talent
straight and bifurcated endografts. METHOD: We treated 5 patients with 3 straight
and 2 bifurcated stent-grafts implanted by surgical femoral arteriotomies and
placed under fluoroscopic guidance. Control CT and angiographic examinations were
performed during an average follow-up of 5.3 months. RESULTS: In the first
patient the procedure had to be converted to an open surgical operation to repo
sition the distal end of the prosthesis. We had no mortality, or major systemic
complication. Three patients had a postimplantation syndrome. All aneurysms
showed a decreased size at 3 months, in spite of 3 small persisting leaks.
CONCLUSION: The Talent endograft is safe, and efficacious in the endovascular
treatment of AAA. This method requires a good cooperation between the vascular
surgeon and the interventional radiologist. Learning curves influence preliminary
results.
PMID- 9757797
TI - [Minimally invasive internal saphenous vein harvesting for coronary artery
bypass].
AB - Harvesting of the great saphenous vein for coronary artery bypass grafting is
usually performed through long cutaneous incisions. We report our experience of
minimally invasive harvest of the saphenous vein using the "Mini Harvest System".
This device is composed of a blade coupled to a light source. Through a small
cutaneous incision, the blade is placed under the skin and allows progressive
dissection of the vein under direct vision. We compare this technique ("minimal
invasive" group, n = 48) to the conventional method in which extensive incisions
are performed along the saphenous vein course ("standard", n = 54). Both groups
are comparable in term of age, sex, diabetes, peripheral arterial disease or
obesity. The number of bypass performed is also comparable in the two groups. The
ratio of the mean length of the cutaneous incision and the mean length of the
vein was 35.4 +/- 5.9% for the "minimal invasive" group and 104.5 +/- 23.3% for
the "standard" group (p < 0.001). The local complication rate is significantly
reduced with a reduction in local post-operative pain (2% vs. 17%, p = 0.01), a
better healing (100% vs. 79%, p = 0.01), a reduction in hematoma (31% vs. 52%, p
= 0.03) and in oedema (37% vs. 59%, p = 0.03). We conclude that besides the
evident aesthetic benefit, minimally invasive harvest of the saphenous vein
allows for a better cicatrization and reduces the post-operative discomfort
without compromising the aorto-coronary bypass procedure.
PMID- 9757798
TI - [How to do: initial experiences with a new device in minimally invasive heart
surgery].
AB - A special surgical technique is required for minimal-invasive cardiac surgery.
The view for the coronary artery anastomosis under beating heart conditions is
important and coronary artery blood might prevent a clear view of the opened
coronary artery vessel. A new system called VisoFlo promises to improve
visualisation at the surgical site. VisoFlo delivers a column of air to help
provide a clear view of anastomosis site and in addition has a controllable mist
to help prevent desiccation of the graft and surrounding tissue. This system was
tested on 45 patients with coronary-artery-bypass graft surgery under beating
heart conditions and at 65 patients with standard coronary-artery-bypass graft
surgery. Our conclusions are, that the VisoFlo system is easy to use, guarantees
a clear view of the anastomosis site and the surgical work will not be impaired.
PMID- 9757799
TI - ["Minimally invasive" surgical closure of the patent foramen ovale].
AB - AIM OF THE STUDY: After the abdomen and the thorax, the cardiac approach seems to
be the logical next step in development of minimally invasive surgery. We report
our initial experience in closure of patient foramen ovale (PFO) through a mini
thoracotomy. METHOD: A cardio-pulmonary bypass is initiated through canulaes
introduced into the external iliac artery and vein. A right anterior mini
thoractomy is performed in the fourth intercostal space and a video-endoscopic
camera is introduced through a trocar placed more laterally. The pericardium is
opened anteriorly to the phrenic nerve. A venous canula is introduced into the
superior vena cava and connected to the extracorporeal circuit. A ventricular
fibrillation is provoked and both vena cavaes are clamped before the right atrium
is opened. The PFO is closed with a double running suture. DISCUSSION: From
November 1996 to march 1997, 4 patients were operated that way. The mean
operation time was 212 +/- 17 minutes, the mean CPB time was 73 +/- 32 minutes,
and the mean fibrillation time was 32 +/- 15 minutes. Echocardiography was
performed at the end of the operations and at day 7. No residual shunt was
detected and the cardiac function was not changed compared to the preoperative
examination. CONCLUSION: Closure of a PFO can be performed through a mini
thoracotomy, with good results. With growing experience, the "minimally invasive"
approach shall rapidly become a standard technique for this indication.
PMID- 9757800
TI - [Hemodynamic effects of maximum laser transmyocardial revascularization].
AB - The aim of this study was to determine the haemodynamic reaction of a heart in
which the left lateral wall was bored with laser channels until cardio-vascular
collapse. Four calves were selected for the study. Series of five channels were
bored with a 1.75 mm diameter laser probe. Each series was followed by a break of
three minutes at the end of which haemodynamic parameters were recorded. The
evolution of these parameters then underwent linear regression analysis.
Calculations were made according to the percentage of the total number of
channels, in order to standardize the results between the animals. Respectively
150, 155, 270 and 285 channels were bored. In each case, all haemodynamic
parameters dropped abruptly during the last series of channels. Central venous
pressure, mean pulmonary artery pressure, wedge pressure, mean arterial pressure
and cardiac output followed a linear regression slope which did not significantly
differ from zero. Heart rate only increased progressively with a liner regression
slope significantly different from zero. In this acute model, haemodynamic
parameters, except heart rate, did not correlate to the extent of damage imposed
on the left ventricle. Thus, the presence of haemodynamic stability does not
exclude important myocardial damage in an acute situation. This can be found in a
clinical setting.
PMID- 9757801
TI - Tissue engineering: a new approach in cardiovascular surgery--seeding of human
fibroblasts on resorbable mesh.
AB - INTRODUCTION: In tissue engineering the material properties of synthetic
compounds are manipulated to enable delivery of dissociated cells onto a scaffold
in a manner that will result in in vitro formation of new functional tissue. The
seeding of human fibroblasts on resorbable mesh is a precondition of a successful
creation of human tissue such as autologous cardiac valves. MATERIAL AND METHODS:
Polymeric scaffolds (n = 12) composed of polyglycolic acid (PGA) with a fiber
diameter of 12-15 mm and a polymer density of 70 mg/ml were used as square sheets
of 0.3 x 1 x 1 cm. Fibroblasts (passage 5), harvested from human foreskin, were
seeded (3.4 x 10(6)) and cultured over a 3 week period on a PGA mesh. RESULTS:
Microscopic examination of the seeded mesh demonstrated that the human
fibroblasts were attached to the polymeric fibers and had begun to spread out and
to divide. Electron microscopy showed a continuous distribution and formation of
the cells throughout the "polymeric architecture". Spotlike hydrolysis of PGA
fibers was observed. After 3 weeks the seeded scaffolds resembled a solid sheet
of tissue. CONCLUSION: These preliminary results, successful seeding of human
fibroblasts on a PGA mesh, represent a first basic step on the way to construct
human tissue such as autologous cardiac valves and demonstrate that tissue
engineering might be a promising new device in therapy of cardiovascular disease.
PMID- 9757802
TI - [Intraoperative and postoperative microdialysis measurement of the human heart-
feasibility and initial results].
AB - STUDY OBJECTIVE: Microdialysis measurements of human cardiac metabolism during
and after cardiac operations have not been published up to now. The goal of this
study was to evaluate feasibility of the method in a clinical setting and to
interpret first results. PATIENTS AND METHODS: In 5 patients microdialysis
measurements were made in regular intervals during aortocoronary bypass surgery.
Analysis of dialysate was done by high performance liquid chromatography or
enzymatic fluorometry. In the last 2 patients measurements were also taken during
the postoperative course up to the time of extubation. RESULTS: During aortic
cross clamping a mean 7-fold rise of the radical scavenger glutathione was
observed (range 0.9-15.4; p = 0.06). During reperfusion the
glucose/lactate(Glc/Lac)-rate rose from 0.4 to 3.1 (p = 0.02). Concentrations of
ascorbic acid, cysteine and uric acid remained neutral or showed no regular
changes. In the 2 patients who were also observed postoperatively, lactate rose
significantly at 190 min and 340 min postoperatively (decrease in Glc/Lac-ratio
from 2.5 to 0.4 and 2.0 to 0.4 respectively). CONCLUSIONS: Microdialytic
measurements of metabolic parameters can be performed on the human heart in a
clinical setting. So far no complications have been observed and the
microdialysis probe can be installed in such a fashion, that it can be easily
removed transcutaneously during the postoperative course. Substances that are
important in ischemia and reperfusion can be measured and their concentrations
show changes that are not just artefacts. Postoperatively, metabolic alterations
may be observed in the myocardial septum that are not recordable with
conventional techniques (i.e., pressure measurements, cardiac output, ECG).
PMID- 9757803
TI - [The significance of endothelial adhesion molecules in heart surgery].
AB - Myocardial ischemia and reperfusion is a common event in cardiovascular surgery
patients. The endothelium has been shown to play a key role in the injury
suffered after ischemia and reperfusion. When endothelial cells became hypoxic
followed by reoxygenation they become activated to express endothelial adhesion
molecules followed by the migration of neutrophils into the tissue. These changes
may contribute to the early postoperatively myocardial dysfunction. An increased
understanding of the interaction between leukocytes and endothelium may allow to
develop new therapies in future.
PMID- 9757804
TI - [The floating joint injury of the lower and upper extremity--epidemiology,
therapy and results in 40 extremities].
AB - GOAL: Floating Joint Injuries (FJI) are resulting from high energy traumas and
are often combined with additional neuro/vascular damage. The high incidence of
severe open or closed soft tissue injuries is complicating the initial management
and requires a broad surgical know-how also in minimal-invasive fixation
techniques. In a retrospective analysis of our cases treated between 1980 and
1995, we try to find out some important therapeutical feedback for the future.
MATERIAL AND METHODS: Of the 37 patients, 33 had a FJI of the lower (2 bilateral)
and 7 patients of the upper extremity. 90% were road traffic injuries, 75% showed
an open fracture situation and 25% an associated neuro-vascular injury. All
fractures were stabilised within the first hours, femur, humerus and forearm in
one step, the tibia in 33% in two steps (initial external fixator ...). 80% of
the FJI have been reexamined after 1-2 y. RESULTS: Local complication: Femur:
4/33 (1 infection, 2 refractures, 1 non-union). Tibia: 11/33 (5 infections, 4
delayed/non-unions, 2 malalignements). Humerus: 0/7. Forearm: 1/7 (1
malalignement). 1-2 y-results: Very good-good: Femur: 26/27 (96%). Tibia: 23/27
(85%). Humerus: 4/5. Forearm: 3/5. DISCUSSION: FJI should be stabilised as soon
as possible in a way allowing for early functional aftercare of the affected
joint. Most complications are observed in the proximal tibia fracture because of
the thin and therefore often severely (open or closed) injured soft tissue cover.
Despite a staged procedure, there exists a high complication rate, which probably
can be reduced in the future by the single-step use of the hybrid external
fixateur.
PMID- 9757805
TI - [Diagnosis and therapy of vascular injuries in posterior knee dislocation].
AB - AIM: We demonstrate the management and treatment of dislocation of the knee
associated with vascular injury. The goal of the treatment is to avoid
complications due to ischemia. The injured vessel can be repaired either by
direct suture or by interposition of a saphenous vein graft. Capsule and
ligaments should be reconstructed secondarily. PATIENTS AND METHODS: The charts
of ten patients treated in the Division of Traumatology of the University of
Zurich between 1979 and 1996 have been retrospectively checked. RESULTS: In eight
of ten patients the injured vessel has been reconstructed with a saphenous vein
graft, in one patient the artery has been repaired by direct suture. In one
patient a flap of the intima has been refixed by endarterectomy. In five patients
the knee has been stabilised with a transfixation (external fixation). In two
patients the ligaments and the capsule were reconstructed at the time of vascular
repair, in seven patients the reconstruction has been performed secondary.
CONCLUSIONS: In case of a dislocation of the knee the examination of the vessels
is mandatory. In case of a critical perfusion the "on table"--angiography is the
procedure of choice. As an alternative method duplex sonography has been
established. The vascular reconstruction is performed by saphenous vein graft
interposition. We recommend to reconstruct ligamentous and capsular structures
secondary.
PMID- 9757806
TI - [Diagnostic reliability of 0.2 Tesla dedicated MRI low-field strength equipment
in traumatology].
AB - Anatomical dedicated low-field-strength MR imaging (non-whole-body-systems) has
been developed for examinations of the peripheral joints. It has several
advantages compared to high-field-strength MR imaging (whole-body-systems). The
dimensions are small, the noise is not as bad as in whole body systems and people
do not suffer of claustrophobic attacks. However, our results of a prospective
blinded study in 56 patients with three different kinds of peripheral joint
injuries demonstrated that the 0.2 T dedicated system showed a significant lower
rate of diagnostic accuracy compared to middle and high-field-strength MR imaging
and scored with obvious lower image quality ratings.
PMID- 9757807
TI - [Value of 3D CT in diagnosis and treatment of fractures of the tibial plateau].
AB - A precise classification and an optimal understanding of tibial plateau fractures
are the basis of a conservative treatment or adequate surgery. The aim of this
prospective study is to determine the contribution of 3D CT to the classification
of fractures (comparison with standard X-rays) and as an aid to the surgeon in
preoperative planning and surgical reconstruction. Between November 1994 and July
1996, 20 patients presenting 22 tibial plateau fractures were considered in this
study. They all underwent surgical treatment. The fractures were classified
according to the Muller AO classification. They were all investigated by means of
standard X-rays (AP, profile, oblique) and the 3D CT. Analysis of the results has
shown the superiority of 3D CT in the planning (easier and more acute), in the
classification (more precise), and in the exact assessment of the lesions
(quantity of fragments); thereby proving to be of undeniable value of the
surgeon.
PMID- 9757808
TI - [Long-term peridural anesthesia and minimally invasive therapy of arthrofibrosis
of the knee joint].
AB - We report on our experiences with continuous epidural anesthesia after
arthrolysis of the knee joint. The restoration of knee motion is the main goal of
our treatment regimen which includes daily passive full mobilisation of the knee
joint with a continuous epidural catheter after arthroscopic lysis and a
functional after treatment with full weight bearing. From December 1992 to
November 1996 32 arthroscopic lysis have been performed at the Surgical
Department of Triemli Hospital in Zurich, Switzerland. The indications for prior
knee surgery included 22 ACL reconstructions, 4 sustained fractures about the
knee and 6 miscellaneous etiologies. Arthroscopic lysis was performed for any
failure in improving knee motion despite intensive physical therapy. According to
Gassen et al. [4] we found one (3.1%) very severe, 5 (15.6%) severe, 12 (37.5%)
moderate and 14 (43.8%) minor cases of arthrofibrosis. After 8 months on average,
a second lysis had to be performed in six cases. All had an ACL reconstruction as
prior surgery, in four out of these six patients only physiotherapeutic after
treatment was performed after the first lysis, 2 patients developed a symptomatic
patella baja. At the end of the treatment after 10 months on average, 16 (50%)
cases showed a very good, 7 (22%) a good, 5 (16%) a satisfactory and 4 (12%) a
poor result concerning range of motion. We think that a daily passive full
mobilisation under regional anesthesia with a continuous epidural catheter is the
key to hold the intraoperatively reached range of motion especially for moderate
to very severe cases of arthrofibrosis.
PMID- 9757809
TI - [Antegrade or retrograde intramedullary nailing in diaphyseal or sub-capital
humeral fractures in the adult].
AB - The aim of this retrospective study was the evaluation of three current medullary
nailing techniques and their approach related problems in diaphyseal and proximal
humeral fractures. 28 patients (15 female, mean age 65 y; 13 male, mean age 53 y)
with either diaphyseal (n = 22) or proximal humeral (n = 6) fractures treated
with different nailing systems were reviewed (mean follow up 18.3 months). Two
main groups were formed according to the surgical approach: an anterograde
nailing group (AN), stabilized with Seidel (Howmedica) nails (n = 12) versus a
retrograde nailing group (RN) with either Prevot (Landos) nails (n = 7) or
Hackethal (Ulrich) nails (n = 9). The two groups were comparable regarding to
age, follow up and fracture type. The subjective scores (global function, all day
activity, pain, ROM) of the two groups (AN and RN) showed no statistically
significant differences. Subacromial impingement led to reoperation in 50% (6/12)
of the AN patients (Seidel nail). In 3/16 patients a reoperation was necessary
due to secondary proximal or distal nail migration (Hackethal or Prevot nails).
Delayed union was found either in one. Seidel or one Prevot nailed humerus. No
postoperative infections or neurological problems (3 preoperative radial palsies
recovered) due to the operative pro cedure were seen. The AN related subacromial
impingement seems to be more disabling than RN related reduction of elbow
function (extension deficit).
PMID- 9757810
TI - [Isolated coracoid fracture--open reposition and osteosynthesis--report of 3
cases].
AB - Usually coracoid-fractures are "chain-injuries" in association with complex
shoulder injuries. Isolated fractures of the coracoid process are uncommon. In
the literature there is no consensus about the treatment. The conservative method
is generally advocated. For better recognizing the particularities of coracoid
anatomy and fracture-analysis we performed dissections on cadaver shoulders and
also evaluated a useful radiologic technique for diagnosis. Between 1995 and 1997
three patients with isolated displaced coracoid-fractures had open surgical
repair. The postoperative course was very good in all three cases with complete
recovery of shoulder function. DISCUSSION: We believe that isolated coracoid
fractures with infero-lateral dislocation and loss of function should sustain
open reduction and internal fixation with functional after treatment.
PMID- 9757812
TI - [Basic principles in local dermatologic therapy].
AB - The vehicle or ointment base plays an important role in dermatological local
treatment. This is true from a therapeutic point of view and with respect to
quality of life as well. Vehicles exert pronounced effects on the epidermis;
these effects include hydration, lubrication, drying, skin smoothness, occlusion
and protection. The vehicle controls the release and penetration, and ultimately
the bioavailability, of the dermatological active ingredients. An overly
simplified rule of thumb is that a deep-layer effect is enhanced by increasing
occlusion. Unfortunately, no uniform classification system exists. Frequently,
users of topical applied products are confused by the non-uniform, and in some
cases erroneous, vehicle designations. In particular, different names are used to
describe the lipophilic emulsion systems. It would be important to consistently
use the official designations here: hydrophilic cream or lipophilic (hydrophobic)
cream or ointment. Dermatological pastes are also often misleading designated,
without any further distinctions, as a uniform occlusive system. For practical
applications, attention must be paid in particular to the different indications
for hydrophilic and lipophilic vehicles. Hydrophilic, aqueous bases are to be
used for acute lesions and seborrhoeic skin, fatty or oily lipophilic systems for
dry hyperkeratotic lesions and sebostatic skin. The cosmetic acceptance of a
vehicle has a direct impact on both compliance and therapeutic effect. More
attention should be paid to these factors. Adverse reactions caused by single
components of the vehicle are not unusual. If a lesion does not respond to local
treatment, the diagnosis should be reconsidered; moreover, the vehicle and its
components should be investigated for possible incompatibility reactions.
PMID- 9757811
TI - [Response of osteoblast cultures to titanium, steel and hydroxyapatite implants].
AB - The biocompatibility of bone implants and substitutes is usually tested on cell
lines only, despite a different and more relevant behaviour on primary
osteoblasts as final targets can be expected. "Osteoblast-like" cell line (MC3T3
E1) and fresh human osteoblasts (HOB), cultured from cancellous bone grafts from
the iliac crest were used for the study. Three different clinically used
biomaterials were compared regarding biocompatibility: titanium, steel and
hydroxyapatite (Bio-Oss). "Osteoblast-like" cell line and fresh human osteoblasts
(5x104) were seeded on the three bone implants. Cell proliferation and
osteocalcin synthesis were determined 1, 3, 7, and 10 days after the cells were
plated on the biomaterials. All experiments were performed in five times (pro
culture double measurements). HOB proliferation on hydroxyapatite was decreasing
after 3 days, whereas cells from "Osteoblast-like" cell line showed comparable
proliferation to the control group. The most interesting observation was the
significant decrease of the osteocalcin levels (in conditioned medium) of
"osteoblast like" cells and HOB on HA (Bio-Oss). We conclude that HA disturbs the
proliferation and osteocalcin synthesis of HOB.
PMID- 9757813
TI - [Therapy of acne vulgaris].
AB - Acne is an eminently curable disease. If therapeutic intervention sets in timely,
scar formation can be prevented. Therapeutic modalities include the topical
agents that should always be combined, and systemic agents, of which
Isotretionoin is of particular importance. Isotretinoin is the only agent that
can induce a complete clearing of acne lesions in 60 to 80% of cases. Adjuvant
therapies, such as local injections, incisions, and peelings, are valuable tools
in everyday practice and may accelerate the clearing of acne lesions. The
treatment of acne is a long term endeavour that needs to be individually tuned to
each patients' needs.
PMID- 9757814
TI - [Psoriasis therapy today].
AB - Psoriasis was already mentioned in the Corpus Hippocratium and only 1842 was it
possible to separate this entity from lepromatous skin manifestations. Psoriasis
is rather common and the prevalence in northern countries ranges between 1-2%.
Psoriasis is an inherited disorder but the clinical manifestations depend on
several triggers such as infections, drugs and stress. The clinical presentation
is characterized by silvery scales on an erythematous ground. The management of
psoriatic patients needs a broad experience. The objective degree of disease
activity as well as the subjective aspects of the disease need to be taken in
account. The therapeutic modalities used in the treatment of psoriasis can be
compared with a symbolic ladder. At the beginning of the ladder emollients are to
be mentioned. Ascending the ladder, different topical treatments can be used such
as steroids or vitamin D and the more severe forms do need systemic treatments
such as ultraviolet therapy, eventually combined with a photosensitizer,
retinoids or methotrexate and even cyclosporine. In special cases treatment as an
outpatient is not possible and then hospitalisation in a dermatologic unit is
necessary.
PMID- 9757815
TI - [Therapeutic management of neurodermatitis atopica].
AB - The therapy of atopic dermatitis remains a challenge. The success of any
therapeutic concept is based on a broad and early diagnostic approach which
allows to rule out relevant provocation factors and allergens. During remission
periods the regular use of a topical basic therapy consisting of drug-free
emolients is recommended. Topical corticosteroids as well as systemic or local
antimicrobial therapy and antihistamines are essential during periods of acute
exacerbations. Although during the last years a great number of new therapeutic
approaches have been published, data of most of these therapeutic modalities are
not sufficient to allow an unrestricted use in all patients with atopic
dermatitis.
PMID- 9757816
TI - [Modern wart therapy].
AB - A description of therapeutic modalities for the treatment of warts is given.
Depending on localisation and types of warts, a variety of therapeutic modalities
are available, which often will lead to eradication of the wart virus infection.
It is important to choose therapies with low scarring potential.
PMID- 9757817
TI - [Therapy of nail mycoses].
AB - Onchomycosis is the most common nail disease, accounting for approximately 30% of
all cutaneous fungal infections. The treatment approach needs to take into
account the location and extent of onychomycosis, sensitivity of drug to fungal
organism, adverse-effects profile, dosage schedule, duration of therapy,
concomitant medical conditions, and concurrent medications. To confirm the
diagnosis, it is important to correctly select the appropriate site for specimen
collection used for both direct microscopy and fungal culture. Topical antifungal
agents may be considered for the treatment of early onychomycosis, in the absence
of nail matrix involvement. The newer generation of oral antifungal agents for
the treatment of onychomycosis are terbinafine, itraconazole and fluconazole.
These drugs used alone, or in combination with topical antifungals, are providing
the basis for effective treatment of onychomycosis in a large proportion of
patients.
PMID- 9757818
TI - [Therapy of cutaneous melanoma].
AB - Therapy of melanoma considers the individual prognosis. Primary low-risk
melanomas with tumor-thickness below 1 mm can be treated by surgery with a safety
margin of 1 cm. If the tumor-thickness is more than 2 mm the safety margin should
be 3 cm. Elective lymph node dissection for melanomas at the extremities is
widely substituted by the sentinel lymph node procedure. This new technique shall
be applied only in specialised centers in the context of clinical trials. After
the resection of lymph node metastases adjuvant treatment using Interferon-alpha
should be considered. Palliative therapy of metastases includes surgery,
radiotherapy and chemo-immunotherapy depending on the number and location of the
metastases. Recent progress in understanding the immunobiology of melanoma and
the development of gene therapy has offered new perspectives for future
therapeutical intervention including peptide vaccination alone or loaded on
dendritic cells and gene therapy.
PMID- 9757819
TI - [Therapy of non-melanocytic skin tumors].
AB - Actinic keratosis on sun-damaged skin are very common in individuals with fair
complexion. Management encompasses cryosurgery, tretinoin or 5-fluorouracil
cream. Bowen's disease, however, requires surgical excision or radiotherapy.
Basal cell carcinoma and squamous cell carcinoma are the two most common
malignant skin tumours in Western Europe. Typically these tumours can be managed
either by excision and primary wound closure, by cryosurgery or by radiotherapy.
The method of choice is determined by the type and location of the tumour and the
general condition of the patient. For more difficult-to-treat malignant skin
tumours surgical resection with histological margin control is required. Mohs'
micrographic surgery is a specialized procedure. This method entails to a full
work-up of the excisional margins. The defect is closed only after histological
verification of tumour-free surgical margins. Difficult-to-treat tumours are
recurrent, sclerodermiform and large (diameter more than 20 mm) basal cell
carcinomas. Indications for margin control in squamous cell carcinomas are
tumours with more than 20 mm of diameter, with more than 5 mm thickness and with
poor histologic differentiation (Broders grade III and IV, desmoplastic squamous
cell carcinoma). Therefore, a skin biopsy is often required to plan the optimal
treatment of a malignant skin tumour. The collaboration of primary care providers
and specialists is beneficial in the management of difficult skin tumours. Renal
transplant recipients under immunosuppression are prone to have squamous cell
carcinoma of a more aggressive type. Dermatofibrosarcoma protuberans is another
good indication for Mohs' micrographic surgery. A regular follow-up for
recurrences or secondary tumours, as well as an effective secondary prevention of
sun damage are important for skin cancer patients.
PMID- 9757820
TI - [Laser therapy in dermatology].
AB - The use of lasers for cutaneous lesions has expanded rapidly since its inception
in the early 1960s. The principle of selective photothermolysis dramatically
improved the efficacy and safety of dermatologic laser systems. Selective
photothermolysis is accomplished by choosing an appropriate wavelength and pulse
duration. According to the target chromophores (hemoglobin, melanin and H2O),
lasers may be grossly divided into 3 groups; systems to treat vascular lesions,
pigmented lesions and the surgical lasers for skin ablation. Although vascular
lesions can be treated with many lasers, the flash lamp pumped dye laser remains
the laser of choice for port wine stains. Cw-lasers can treat telangiectases
without purpura and are safer when used in conjunction with scanning devices. Q
switched lasers have enhanced our ability to treat pigmented lesions, especially
tattoos. The carbon dioxide laser remains the "workhorse" in dermatology. Safety
and versatility are maximized when coupled with a scanning device or utilized in
a high-powered, rapidly pulsed mode. Despite the expanding list of laser
responsive lesions, other therapeutic modalities, sometimes at least equally
effective and cheaper, must be carefully considered. This requires skill in
dermatology and basic laser principles. Lasers add a substantial dimension in
treating various skin disorders but are increasingly fraught with overuse.
PMID- 9757821
TI - [Topical photodynamic therapy in dermatology].
AB - Photodynamic therapy (PDT) is an experimental, noninvasive treatment of different
malignant tumors. The principle is that applied photosensitizing substance
selectively accumulate in neoplastic cells. Exposure to visible light then leads
to the destruction of the tumor tissue. Following intravenous or oral
administration of the photosensitizer (PS) generalised skin photosensitivity is
the major side effect. Topical application of the PS under occlusive foil a novel
method. Topical PDT (TPDT) is most investigated with 5-Aminolevulinic acid (ALA)
as PS. ALA is a precursor of endogenous porphyrins in the biosynthetic pathway
for heme. This new modality is increasingly and successfully used to treat
precancerous and cancerous epithelial skin tumors, like actinic keratoses, basal
cell carcinoma, squamous-cell carcinoma and Bowen disease. An other approach of
ALA-TPDT are nontumoral applications, especially psoriasis. ALA-TPDT is well
tolerated by patients and makes excellent cosmetic results. It is an alternative
treatment for various superficial skin tumors.
PMID- 9757822
TI - Novel homologs of replication protein A in archaea: implications for the
evolution of ssDNA-binding proteins.
AB - In Bacteria and Eukarya, ssDNA-binding proteins are central to most aspects of
DNA metabolism. Until recently, however, no counterpart of an ssDNA-binding
protein had been identified in the third domain of life, Archaea. Here, we report
the discovery of a novel type of ssDNA-binding protein in the genomes of several
archaeons. These proteins, in contrast to all known members of this protein
family, possess four conserved DNA-binding sites within a single polypeptide or,
in one case, two polypeptides. This peculiar structural organization allows us to
propose a model for the evolution of this class of proteins.
PMID- 9757823
TI - A unified DNA- and dNTP-binding mode for DNA polymerases.
AB - Crystal structures of various DNA polymerases show a common structural topology
that resembles a right hand and has distinct finger, palm and thumb subdomains.
Early models of the klenow fragment (KF) of Escherichia coli polymerase I showed
DNA entering a large cleft that faces the palm subdomain where the catalytic site
is situated1,2. However, subsequent resolution of the structures of HIV-1 reverse
transcriptase, KF and polymerase beta (pol beta) bound to DNA3-5 yielded
conflicting data that suggested a different orientation for DNA bound to pol beta
compared with DNA bound to other polymerases. The debate, on the correct
orientation of the template-primer DNA, that followed failed to reach a
consensus. Using an alternative superposition scheme, we now provide convincing
evidence for a common DNA-binding mode that is applicable to all polymerases,
including pol beta.
PMID- 9757825
TI - Sensitive to the yoctomole limit.
PMID- 9757824
TI - The FERM domain: a unique module involved in the linkage of cytoplasmic proteins
to the membrane.
PMID- 9757826
TI - A new family of phosphotransferases related to P-type ATPases.
PMID- 9757827
TI - The HORMA domain: a common structural denominator in mitotic checkpoints,
chromosome synapsis and DNA repair.
PMID- 9757828
TI - A superfamily of proteins that contain the cold-shock domain.
AB - Members of a family of cold-shock proteins (CSPs) are found throughout the
eubacterial domain and appear to function as RNA-chaperones. They have been
implicated in various cellular processes, including adaptation to low
temperatures, cellular growth, nutrient stress and stationary phase. The
discovery of a domain--the cold-shock domain--that shows strikingly high homology
and similar RNA-binding properties to CSPs in a growing number of eukaryotic
nucleic-acid-binding proteins suggests that these proteins have an ancient
origin.
PMID- 9757829
TI - The INK4a/ARF tumor suppressor: one gene--two products--two pathways.
AB - Functional inactivation of the retinoblastoma (RB) and p53 pathways appears to be
a rite of passage for all cancerous cells and results in disruption of cell-cycle
regulation and deactivation of the apoptotic response that normally ensues. The
INK4a/ARF locus sits at the nexus of these two growth-control pathways, by virtue
of its ability to generate two distinct products: the p16INK4a protein, a cyclin
dependent kinase inhibitor that functions upstream of RB; and the p19ARF protein,
which blocks MDM2 inhibition of p53 activity. This 'one gene--two products--two
pathways' arrangement provides a basis for the prominence of INK4a/ARF in
tumorigenesis.
PMID- 9757830
TI - Nucleic-acid-chaperone activity of retroviral nucleocapsid proteins: significance
for viral replication.
AB - Retrovirus particles contain a small, basic protein, the nucleocapsid (NC)
protein, that possesses 'nucleic acid chaperone' activity--that is, the NC
protein can catalyze the rearrangement of a nucleic acid molecule into the
conformation that has the maximal number of base pairs. The molecular mechanism
that underlies this effect is not understood. Because the chaperone activity is
apparently crucial during the infectious process, NC is a potential target for
antiviral therapy.
PMID- 9757832
TI - MAPs, MARKs and microtubule dynamics.
AB - Microtubules (MTs) serve as tracks for cellular transport, and regulate cell
shape and polarity. Rapid transitions between stable and dynamic forms of MTs are
central to these processes. This dynamic instability is regulated by a number of
cellular factors, including the structural MT-associated proteins (MAPs), which
in turn are regulated by phosphorylation. MT-affinity-regulating kinases (MARKs)
are novel mammalian serine/threonine kinases that phosphorylate the tubulin
binding domain of MAPs and thereby cause their detachment from MTs and increased
MT dynamics. Molecular cloning of MARKs revealed a family of four closely related
protein kinases that share homology with genes from the nematode Caenorhabditis
elegans and fission yeast that are involved in the generation of cell shape and
polarity. Hence, MARKs might play a role in the regulation of MT stability during
morphogenesis.
PMID- 9757833
TI - Forty years under the central dogma.
PMID- 9757831
TI - Gathering STYX: phosphatase-like form predicts functions for unique protein
interaction domains.
AB - The effects of tyrosine phosphorylation are manifested and regulated through
protein domains that bind to specific phosphotyrosine motifs. STYX is a unique
modular domain found within proteins implicated in mediating the effects of
tyrosine phosphorylation in vivo. Individual STYX domains are not catalytically
active; however, they resemble protein tyrosine phosphatase (PTP) domains and,
like PTPs, contain core sequences that recognize phosphorylated substrates. Thus,
the STYX domain adds to the repertoire of modular domains that can mediate
intracellular signaling in response to protein phosphorylation.
PMID- 9757834
TI - Girls' and boys' differing response to pain starts early in their lives.
PMID- 9757835
TI - Tragic loss of leaders in AIDS and public health.
PMID- 9757836
TI - Unacceptable nursing home deaths unautopsied.
PMID- 9757837
TI - Washington marchers unite to conquer cancer.
PMID- 9757839
TI - From the Centers for Disease Control and Prevention. Maternal mortality--United
States, 1982-1996.
PMID- 9757838
TI - Challenging report on pregnancy and drug abuse.
PMID- 9757840
TI - From the Centers for Disease Control and Prevention. Recommendations of the
Advisory Committee on Immunization Practices, the American Academy of Pediatrics,
and the American Academy of Family Physicians: use of reminder and recall by
vaccination providers to increase vaccination rates.
PMID- 9757841
TI - President's address. Packing my bag for the road ahead.
PMID- 9757842
TI - Diagnosis, treatment, and prevention of Lyme disease.
PMID- 9757843
TI - Diagnosis, treatment, and prevention of Lyme disease.
PMID- 9757844
TI - Diagnosis, treatment, and prevention of Lyme disease.
PMID- 9757845
TI - Diagnosis, treatment, and prevention of Lyme disease.
PMID- 9757846
TI - The ungifted physician.
PMID- 9757847
TI - The ungifted physician.
PMID- 9757848
TI - The ungifted physician.
PMID- 9757849
TI - Physician recommendations vs insurance coverage for growth hormone.
PMID- 9757850
TI - Physician recommendations vs insurance coverage for growth hormone.
PMID- 9757851
TI - Physician recommendations vs insurance coverage for growth hormone.
PMID- 9757852
TI - Importance of hemodynamic factors in the prognosis of symptomatic carotid
occlusion.
AB - CONTEXT: The relative importance of hemodynamic factors in the pathogenesis and
treatment of stroke in patients with carotid artery occlusion remains
controversial. OBJECTIVE: To test the hypothesis that stage II cerebral
hemodynamic failure (increased oxygen extraction measured by positron emission
tomography [PET]) distal to symptomatic carotid artery occlusion is an
independent risk factor for subsequent stroke in medically treated patients.
DESIGN AND SETTING: Prospective, blinded, longitudinal cohort study of patients
referred from a group of regional hospitals between 1992 and 1996. PATIENTS: From
419 subjects referred, 81 with previous stroke or transient ischemic attack in
the territory of an occluded carotid artery were enrolled. All were followed up
to completion of the study, with average follow-up of 31.5 months. MAIN OUTCOME
MEASURES: Telephone contact every 6 months recorded the subsequent occurrence of
all stroke, ipsilateral ischemic stroke, and death. RESULTS: Stroke occurred in
12 of 39 patients with stage II hemodynamic failure and in 3 of 42 patients
without (P = .005); stroke was ipsilateral in 11 of 39 patients with stage II
hemodynamic failure and in 2 of 42 patients without (P = .004). Six deaths
occurred in each group (P = .94). The age-adjusted relative risk conferred by
stage II hemodynamic failure was 6.0 (95% confidence interval [CI], 1.7-21.6) for
all stroke and 7.3 (95% CI, 1.6-33.4) for ipsilateral stroke. CONCLUSIONS: Stage
II hemodynamic failure defines a subgroup of patients with symptomatic carotid
occlusion who are at high risk for subsequent stroke when treated medically. A
randomized trial evaluating surgical revascularization in this high-risk subgroup
is warranted.
PMID- 9757853
TI - Low-dose hydrocortisone for treatment of chronic fatigue syndrome: a randomized
controlled trial.
AB - CONTEXT: Chronic fatigue syndrome (CFS) is associated with a dysregulated
hypothalamic-pituitary adrenal axis and hypocortisolemia. OBJECTIVE: To evaluate
the efficacy and safety of low-dose oral hydrocortisone as a treatment for CFS.
DESIGN: A randomized, placebo-controlled, double-blind therapeutic trial,
conducted between 1992 and 1996. SETTING: A single-center study in a tertiary
care research institution. PATIENTS: A total of 56 women and 14 men aged 18 to 55
years who met the 1988 Centers for Disease Control and Prevention case criteria
for CFS and who withheld concomitant treatment with other medications.
INTERVENTION: Oral hydrocortisone, 13 mg/m2 of body surface area every morning
and 3 mg/m2 every afternoon, or placebo, for approximately 12 weeks. MAIN OUTCOME
MEASURES: A global Wellness scale and other self-rating instruments were
completed repeatedly before and during treatment. Resting and cosyntropin
stimulated cortisol levels were obtained before and at the end of treatment.
Patients recorded adverse effects on a checklist. RESULTS: The number of patients
showing improvement on the Wellness scale was 19 (54.3%) of 35 placebo recipients
vs 20 (66.7%) of 30 hydrocortisone recipients (P =.31). Hydrocortisone recipients
had a greater improvement in mean Wellness score (6.3 vs 1.7 points; P=.06), a
greater percentage (53% vs 29%; P=.04) recording an improvement of 5 or more
points in Wellness score, and a higher average improvement in Wellness score on
more days than did placebo recipients (P<.001). Statistical evidence of
improvement was not seen with other self-rating scales. Although adverse symptoms
reported by patients taking hydrocortisone were mild, suppression of adrenal
glucocorticoid responsiveness was documented in 12 patients who received it vs
none in the placebo group (P<.001). CONCLUSIONS: Although hydrocortisone
treatment was associated with some improvement in symptoms of CFS, the degree of
adrenal suppression precludes its practical use for CFS.
PMID- 9757854
TI - Prevention of estrogen deficiency-related bone loss with human parathyroid
hormone-(1-34): a randomized controlled trial.
AB - CONTEXT: Short-term intermittent administration of parathyroid hormone (PTH)
prevents bone loss from the spine in women treated with a gonadotropin-releasing
hormone (GnRH) analog. However, the effects of a longer period of PTH
administration on bone mass in estrogen-deficient women, particularly on the hip
and on cortical bone of the total body, are unknown. OBJECTIVE: To determine
whether more prolonged PTH administration can prevent estrogen deficiency bone
loss from the hip, spine, and total body in young women with endometriosis
receiving GnRH analog (nafarelin acetate) therapy. DESIGN: Randomized controlled
trial. SETTING: General Clinical Research Center of a tertiary care, university
affiliated hospital. PATIENTS: Forty-three women between the ages of 21 and 45
years with symptomatic endometriosis. INTERVENTION: Nafarelin alone (200 microg
intranasally twice daily) or nafarelin plus human parathyroid hormone-(1-34)
(hPTH-[1-34]) (40 microg subcutaneously daily). MAIN OUTCOME MEASURES: The
primary end points were bone mineral density (BMD) of the anterior-posterior and
lateral spine, femoral neck, trochanter, radial shaft, and total body at 12
months of treatment. RESULTS: In the women who received nafarelin alone, the mean
(SEM) BMDs of the anterior-posterior spine, lateral spine, femoral neck,
trochanter, and total body were 4.9% (0.6%) (P<.001), 4.9% (0.8%) (P<.001), 4.7%
(1.1%) (P<.001), 4.3% (0.9%) (P<.001), and 2.0% (0.6%) (P= .003) lower than at
baseline after 12 months of therapy. In contrast, coadministration of hPTH-(1-34)
increased BMD of the anterior-posterior spine by 2.1% (1.1%) (P=.09) and lateral
spine by 7.5% (1.9%) (P=.002) and prevented bone loss from the femoral neck,
trochanter, and total body, despite severe estrogen deficiency. Radial shaft BMD
did not change significantly in either group. Serum bone-specific alkaline
phosphatase and osteocalcin concentrations and urinary excretion of
hydroxyproline and deoxypyridinoline increased 2-fold to 3-fold during the first
6 to 9 months of therapy in the women who received nafarelin plus hPTH-(1-34) and
then declined. Changes in urinary deoxypyridinolone excretion were strongly
predictive (r= 0.85) of changes in spinal BMD in the women who received nafarelin
plus hPTH-(1-34). CONCLUSIONS: Parathyroid hormone prevents bone loss from the
proximal femur and total body and increases lumbar spinal BMD in young women with
GnRH analog-induced estrogen deficiency.
PMID- 9757855
TI - Modulation of abnormal colonic epithelial cell proliferation and differentiation
by low-fat dairy foods: a randomized controlled trial.
AB - CONTEXT: Before the development of human colonic neoplasms, colonic epithelial
cells showed altered growth and differentiation. These alterations characterized
mucosa at risk for cancer formation and were termed intermediate biomarkers of
risk. Modifications of the mucosa toward more normal features by nutrients or
drugs are putative approaches to chemoprevention of colon cancer. OBJECTIVE: To
determine whether increasing calcium intake via dairy products alters colonic
biomarkers toward normal. DESIGN: Randomized, single-blind, controlled study.
SETTING: Outpatient clinic. PARTICIPANTS: Seventy subjects with a history of
polypectomy for colonic adenomatous polyps. INTERVENTION: Low-fat dairy products
containing up to 1200 mg/d of calcium. Subjects were randomized to 4 strata by
diet (control vs higher calcium) and age (<60 vs > or = 60 years). MAIN OUTCOME
MEASURES: Changes in total colonic epithelial cells and number and position of
thymidine-labeled epithelial cells and changes in the ratio of sulfomucins
(predominantly secreted by distal colorectal epithelial cells) to sialomucins and
expression of cytokeratin AE1, 2 markers of colonic cell differentiation.
RESULTS: During 6 and 12 months of treatment, reduction of colonic epithelial
cell proliferative activity (P<.05), reduction in size of the proliferative
compartment (P<.05), and restoration of acidic mucin (P<.02), cytokeratin AE1
distribution (P<.05), and nuclear size (P<.05) toward that of normal cells
occurred. Control subjects showed no differences from baseline proliferative
values at 6 and 12 months (P>.05). CONCLUSION: Increasing the daily intake of
calcium by up to 1200 mg via low-fat dairy food in subjects at risk for colonic
neoplasia reduces proliferative activity of colonic epithelial cells and restores
markers of normal cellular differentiation.
PMID- 9757857
TI - A 55-year-old man with attention-deficit/hyperactivity disorder.
PMID- 9757858
TI - A 73-year-old man with symptomatic benign prostatic hyperplasia, 1 year later.
PMID- 9757856
TI - False-positive HIV-1 test results in a low-risk screening setting of voluntary
blood donation. Retrovirus Epidemiology Donor Study.
AB - CONTEXT: Persons at risk of human immunodeficiency virus 1 (HIV-1) infection,
have been classified incorrectly as HIV infected because of Western blot results,
but the frequency of false-positive Western blot results is unknown. OBJECTIVES:
To determine the frequency of false-positive HIV-1 Western blot results in US
blood donors and to make projections to other screened populations. Secondarily,
to validate an algorithm for evaluating possible false-positive cases. DESIGN: A
retrospective cohort study of HIV-1 enzyme immunoassay (EIA) and Western blot
results from large blood donor screening programs in which donors with suspected
false-positive Western blot results underwent HIV-1 RNA polymerase chain reaction
(PCR) testing and follow-up HIV-1 serology. SETTING: Five US blood centers
participating in the Retrovirus Epidemiology Donor Study. PARTICIPANTS: More than
5 million allogeneic and autologous blood donors who successfully donated blood
at 1 of the 5 participating centers from 1991 through 1995. MAIN OUTCOME
MEASURES: Rate of false positivity by Western blot and true HIV-1 infection
status as determined by HIV-1 RNA PCR and by serologic follow-up of blood donors
more than 5 weeks after donation. RESULTS: Of 421 donors who were positive for
HIV-1 by Western blot, 39 (9.3%) met the criteria of possible false positivity
because they lacked reactivity to p31. Of these, 20 (51.3%) were proven by PCR
not to be infected with HIV-1. The false-positive prevalence was 4.8% of Western
blot-positive donors and 0.0004% (1 in 251000) of all donors (95% confidence
interval, 1 in 173000 to 1 in 379000 donors). CONCLUSIONS: A false diagnosis of
HIV-1 infection can result from the combination of EIA and Western blot testing
in blood donor and other HIV-1 screening programs. Individuals with a positive
Western blot result lacking the p31 band should be counseled that, although they
may be HIV infected, there is uncertainty about this conclusion. These
individuals should be further evaluated by RNA PCR testing (if feasible) and HIV
serologic analysis on a follow-up sample.
PMID- 9757859
TI - Occlusion of the internal carotid artery: reopening a closed door?
PMID- 9757860
TI - The nature of chronic fatigue.
PMID- 9757861
TI - Proliferation happens.
PMID- 9757862
TI - Two tiers of physicians in France: general pediatrics declines, general practice
rises.
PMID- 9757864
TI - JAMA patient page: stroke.
PMID- 9757863
TI - Physicians as double agents: maintaining trust in an era of multiple
accountabilities.
PMID- 9757865
TI - Genetic risks of intracytoplasmic sperm injection in the treatment of male
infertility: recommendations for genetic counseling and screening.
AB - OBJECTIVE: To review the most clinically significant genetic disorders associated
with severe oligospermia and azoospermia in males, and to present recommendations
for the genetic counseling and screening of infertile males and their partners
before undertaking intracytoplasmic sperm injection (ICSI)-assisted reproduction.
DESIGN: The literature on genetic disorders associated with severe oligospermia
and azoospermia was reviewed, and the most recent outcome data from surveys of
ICSI-derived offspring are presented. Studies related to this topic were
identified through MEDLINE. RESULT(S): Genetic disorders are not infrequent
causes of severe oligospermia and azoospermia in males undergoing ICSI-assisted
reproduction. The application of ICSI in the treatment of oligospermic or
azoospermic males may result in the transmission or de novo introduction of
genetic mutations or chromosomal abnormalities in their offspring. Genetic
counseling and appropriate screening of couples with male infertility should be
performed before their undertaking ICSI-assisted reproduction. CONCLUSIONS: An
understanding of the genetic risks and possible consequences that are inherent
when ICSI is used to assist fertilization in couples with male infertility is
necessary for clinicians and their patients.
PMID- 9757866
TI - Genetic counseling for patients who will be undergoing treatment with assisted
reproductive technology.
PMID- 9757867
TI - Shared-risk or refund programs in assisted reproduction. The Ethics Committee of
the American Society for Reproductive Medicine.
PMID- 9757868
TI - The ethics of guaranteeing patient outcomes.
PMID- 9757869
TI - Ethics of guaranteeing patient outcomes: a complex issue whose time has not come.
PMID- 9757870
TI - The follicular and endocrine environment in women with endometriosis: local and
systemic cytokine production.
AB - OBJECTIVE: To assess the endocrine, paracrine, and autocrine milieu in patients
with endometriosis on the basis of the measurement of several cytokines in serum
and follicular fluid (FF) and in vitro culture of granulosa luteal cells. DESIGN:
Case-control study. SETTING: In vitro fertilization program at the Instituto
Valenciano de Infertilidad. PATIENT(S): Twenty patients with laparoscopically
documented endometriosis and 18 controls. Fifteen subjects were studied in a
natural cycle and 23 were investigated in a stimulated cycle while undergoing
IVF. INTERVENTION(S): Individual follicle aspiration, oocyte isolation, FF
storage, and preparation of luteinized granulosa cell cultures. Diagnostic
laparoscopy in natural cycles. MAIN OUTCOME MEASURE(S): Serum (day of ovum pick
up or laparoscopy) and FF measurement of interleukin (IL)-1beta, IL-6, and
vascular endothelial growth factor (VEGF). Secretion of IL-1beta, IL-6, and VEGF
in the cell-conditioned medium. Results were compared between patients with
endometriosis and controls. RESULT(S): Interleukin-6 levels in serum were
increased in the natural cycles of patients with endometriosis and modulated by
ovarian stimulation, showing a significant decrease in hMG- and FSH-stimulated
cycles and a significant increase after hCG administration. In addition, IL-6
levels were increased in the FF of patients with endometriosis and released in
higher amounts by their granulosa luteal cells. Vascular endothelial growth
factor was accumulated in lesser concentrations in the FF of patients with
endometriosis. Interleukin-1beta levels did not show significant changes.
Implantation rates were decreased significantly in patients with endometriosis
who were undergoing IVF. CONCLUSION(S): The data demonstrate that cytokines are
regulated differently in patients with endometriosis, who have increased IL-6
production, and suggest that fine hormonal modulation of this cytokine occurs at
the systemic and local (ovarian) levels. These changes show that the endocrine,
paracrine, and autocrine milieu is different in patients with endometriosis and
may be related to their lower implantation rates.
PMID- 9757871
TI - A prospective study of reproductive factors and oral contraceptive use in
relation to the risk of uterine leiomyomata.
AB - OBJECTIVE: To investigate the risk of uterine leiomyomata in relation to
reproductive factors and oral contraceptive use. DESIGN: A prospective study.
SETTING: A cohort of female registered nurses from 14 states in the United States
who completed mailed questionnaires in 1989, 1991, and 1993. PATIENT(S):
Premenopausal nurses (n=95,061) aged 25-42 years with intact uteri and no history
of diagnosed uterine leiomyomata or cancer in 1989. INTERVENTION(S): None. MAIN
OUTCOME MEASURE(S): Incidence of self-reported uterine leiomyomata confirmed by
ultrasound or hysterectomy. In a sample of 243 cases, 93% of the self-reported
diagnoses were confirmed in the medical record. RESULT(S): During 326,116 person
years of follow-up, 3,006 cases of uterine leiomyomata, confirmed by ultrasound
or hysterectomy, were reported. After adjustment for other risk factors, the risk
of uterine leiomyomata was significantly inversely associated with age at
menarche, parity, and age at first birth, and positively associated with a
history of infertility and years since last birth. The only notable association
with any aspect of oral contraceptive use was a significantly elevated risk among
women who first used oral contraceptives at ages 13-16 years compared with those
who had never used oral contraceptives. CONCLUSION(S): Reproductive factors and
oral contraceptive use at a young age influence the risk of uterine leiomyomata
among premenopausal women.
PMID- 9757872
TI - Reproductive sequelae in female rats after in utero and neonatal exposure to the
phytoestrogen genistein.
AB - OBJECTIVE: To determine reproductive sequelae in female rats after in utero and
lactational dietary exposure to genistein. DESIGN: Experimental animal study.
SETTING: University laboratory. ANIMAL(S): Sprague Dawley rats. INTERVENTION(S):
Pregnant rats were fed control rat chow or rat chow incorporated with genistein
(approximately 50 microg/d) beginning on day 17 of gestation and continuing until
the end of lactation (postpartum day 21). Genistein-exposed female pups were
divided into two groups on day 21. One group continued to receive a genistein
added diet (G70); the other group was changed to a control diet (Ex-G). At
necropsy (days 21 and 70), blood and reproductive tissues were collected. MAIN
OUTCOME MEASURE(S): Serum levels of gonadotropins and gonadal steroids and
histopathologic examination of the ovaries. RESULT(S): The weight of the ovaries
and uterus and serum levels of E2 and progesterone in genistein-exposed rats on
day 21 (G21) were significantly reduced compared with control rats. On day 70,
serum levels of E2, progesterone, LH, and FSH were similar in all groups. Atretic
follicles and secondary interstitial glands were more common in G70 and Ex-G rats
compared with control rats. Cystic rete ovarii was observed in some G70 and Ex-G
rats. CONCLUSION(S): Our data indicate that in utero and lactational exposure to
dietary genistein adversely affects reproductive processes in the adult female
rat.
PMID- 9757873
TI - The World Health Organization Multinational Study of Breast-feeding and
Lactational Amenorrhea. I. Description of infant feeding patterns and of the
return of menses. World Health Organization Task Force on Methods for the Natural
Regulation of Fertility.
AB - OBJECTIVE: To detect differences between populations in both infant feeding
practices and the duration of lactational amenorrhea, if they exist. DESIGN:
Prospective, nonexperimental, longitudinal follow-up study. SETTING: Five
developing and two developed countries. PATIENT(S): Four thousand one hundred
eighteen breast-feeding mothers and their infants. INTERVENTION(S): Breast
feeding women collected ongoing information about infant feeding and family
planning practices, plus the return of menses. Fortnightly follow-up occurred in
the women's homes. MAIN OUTCOME MEASURE(S): Breast-feeding frequency by day (and
by night); 24-hour breast-feeding duration, percent of all infant feedings that
were milk/milk-based (and solid/semisolid foods); time until the end of full
breast-feeding; time until regular supplementation; and time until the end of
lactational amenorrhea. RESULT(S): Differences between the centers in the
duration of amenorrhea were substantial, ranging from a median of 4 months in New
Delhi (India) to 9 months in Chengdu (China). Women in developed countries (but
also women in Chengdu) were more likely to delay supplementation (for up to 5
months), whereas women in Santiago (Chile), Guatemala City (Guatemala), and
Sagamu (Nigeria) started supplements much earlier, sometimes as early as 1 week
after birth. CONCLUSION(S): Both breast-feeding behavior and the duration of
lactational amenorrhea vary markedly across settings, indicating that breast
feeding promotion and family planning advice should be site- and culture
specific.
PMID- 9757874
TI - The World Health Organization Multinational Study of Breast-feeding and
Lactational Amenorrhea. II. Factors associated with the length of amenorrhea.
World Health Organization Task Force on Methods for the Natural Regulation of
Fertility.
AB - OBJECTIVE: To determine the relation between infant feeding practices (and other
factors) and the duration of postpartum amenorrhea, and to establish whether
there are real differences in the duration of postpartum amenorrhea for similar
breast-feeding practices in different populations. DESIGN: Prospective,
nonexperimental, longitudinal follow-up study. SETTING: Five developing and two
developed countries. PATIENT(S): Four thousand one hundred eighteen breast
feeding mothers and their infants. INTERVENTION(S): Breast-feeding women
collected ongoing information about infant feeding and family planning practices,
plus the return of menses. Fortnightly follow-up occurred in the women's homes.
MAIN OUTCOME MEASURE(S): A multivariate analysis explored the association between
the risk of menses return and 16 infant feeding variables and 11 other
characteristics. RESULT(S): Ten factors (in addition to center effects) were
significantly related to the duration of amenorrhea. Seven of these were infant
feeding characteristics and the remaining three were high parity, low body mass
index, and a higher frequency of infant illness. CONCLUSION(S): The breast
feeding stimulus is strongly linked to the duration of postpartum amenorrhea.
Cross-cultural effects also are extremely important and may have caused the
variations in feeding, the variation in amenorrhea, or both.
PMID- 9757875
TI - Serum leptin concentration in women: effect of age, obesity, and estrogen
administration.
AB - OBJECTIVE: To compare serum leptin levels in normally cycling reproductive
females (20-35 years old) with those in age-matched males, in women who were
receiving oral contraceptives, and in older (postmenopausal) women (50-65 years
old) who were or who were not receiving hormone replacement therapy. DESIGN: Case
control study. SETTING: Obstetrics and Gynecology Clinic, Texas Tech University
Health Sciences Center-Amarillo, or the Exercise Physiology Laboratory at
Southeastern Louisiana University. PATIENT(S): Normally cycling women between the
ages of 20-35 years and age-matched controls who were receiving oral
contraceptives. Postmenopausal women between the ages of 50-65 years who were or
who were not receiving hormone replacement therapy. MAIN OUTCOME MEASURE(S):
Serum leptin concentration. RESULT(S): In all groups, serum leptin concentrations
were correlated significantly with body mass index. Leptin levels were
significantly higher in young women than young men (P <.001), but no other
statistically significant differences were found for the other three comparisons.
CONCLUSION(S): Serum leptin concentrations expressed as a measure of adiposity
(body mass index) are greater in young normally cycling females (20-35 years old)
than in age-matched males. There is no difference in levels of serum leptin
between young and postmenopausal (50-65 years old) women. Estrogen
administration, either in young women who are receiving estrogen-progestin oral
contraceptives or in postmenopausal women who are receiving hormone replacement
therapy, does not effect serum leptin concentrations.
PMID- 9757876
TI - Probabilities for singleton and multiple pregnancies after in vitro
fertilization.
AB - OBJECTIVE: To help physicians provide risk estimates for specific pregnancy
outcomes. DESIGN: Computation of exact binomial probabilities for singleton and
multiple pregnancies as a function of two inputs: the number of embryos
transferred and the implantation rate. Inputs were varied over the range of
values reported in the literature. MAIN OUTCOME MEASURE(S): Probabilities for a
singleton pregnancy (none), a multiple pregnancy (Pmult), and no pregnancy
(Pnone) after one IVF cycle. RESULT(S): Given a 30% implantation rate and three
embryos transferred, Pone=.44, Pmult=.22, and Pnone=.34. Although further
increasing the number of embryos transferred increases the chance of pregnancy,
it also raises the probability of a multiple pregnancy and lowers the chance of a
singleton pregnancy. Although varying the implantation rate changes the specific
probability estimates, the same trade-off persists. CONCLUSION(S): Those who
consider an IVF "success" to be a singleton pregnancy should be attentive to the
number of embryos transferred. Infertility therapy may be one area in medicine
where more is not necessarily better.
PMID- 9757877
TI - Mannose ligand receptor assay as a test to predict fertilization in vitro: a
prospective study.
AB - OBJECTIVE: To assess whether mannose receptor assays can predict fertilization
outcome in vitro. DESIGN: A prospective, double-blind study of the mannose
receptor properties of spermatozoa. SETTING: Assisted human reproduction program
at a university hospital. PATIENT(S): Partners of 140 consecutive women
undergoing their first in vitro fertilization cycle. INTERVENTION(S): Motile
sperm populations were tested for surface receptors for mannose by measuring
their ability to bind fluorescein-labeled mannosylated albumin and to undergo a
free mannose-induced acrosome reaction as judged by Pisum, sativum agglutinin
binding. MAIN OUTCOME MEASURE(S): Mannose receptor assay results were correlated
with fertilization outcomes using several statistical tests, including the chi2
test, chi2 for proportions, t-tests, analysis of variance with Student-Newman
Keuls tests and correlational and receiver operating characteristic (ROC) curve
analysis. RESULT(S): The fractional increment increase on incubation in the
percent of sperm binding mannose ligand over an intact acrosome correlated with
fertilization rates in vitro. Threshold values of mannose ligand binding and of
mannose-induced acrosome reactions predictive of fertilization rates were
identified by ROC curve analysis. Men were thus classified into one of four
groups with differing fertilization rates in vitro. CONCLUSION(S): The increment
increase in sperm surface mannose ligand binding by acrosome-intact sperm
correctly predicts high and low fertilization rates in vitro and identifies cases
where conventional insemination can result in failed fertilization.
PMID- 9757878
TI - Adverse effects of hydrosalpinx on pregnancy rates after in vitro fertilization
embryo transfer.
AB - OBJECTIVE: To determine the effect of hydrosalpinx on the establishment of
pregnancy after IVF-ET. DESIGN: Metaanalysis. SETTING: University medical center.
PATIENT(S) AND INTERVENTION(S): All published reports (n=13) and abstracts (n=10)
in English that examined the relation between hydrosalpinx and IVF-ET were
included in the analysis. The metaanalysis was performed by first calculating the
odds ratios for each trial and then combining them to obtain a pooled estimate of
the odds ratio and a 95% confidence interval. MAIN OUTCOME MEASURE(S): Clinical
pregnancy. RESULT(S): A total of 5,569 cycles was reviewed in the group without
hydrosalpinx, and a total of 1,144 was reviewed in the group with hydrosalpinx.
The clinical pregnancy rate was approximately 50% lower in patients who had
hydrosalpinx. Similarly, the implantation rate was decreased by 50%. These
effects were observed also in thawed ET cycles. The abortion rate was more than
twofold higher in patients who had hydrosalpinx. CONCLUSION(S): This metaanalysis
suggests that hydrosalpinx is associated with a reduced chance of implantation
and an increased risk of pregnancy loss.
PMID- 9757879
TI - Outcome of pregnancies after intracytoplasmic sperm injection and the effect of
sperm origin and quality on this outcome.
AB - OBJECTIVE: To describe the outcome of pregnancies obtained after intracytoplasmic
sperm injection (ICSI) and the impact of the origin and quality of sperm used on
this outcome. DESIGN: Retrospective analysis. SETTING: A tertiary referral center
for assisted reproduction. PATIENT(S): Pregnant patients conceived after
microinjection of ejaculated sperm (n=1,427), epididymal sperm (n=79), and
testicular sperm (n=93). INTERVENTION(S): ICSI, epididymal sperm aspiration, and
testicular biopsy. MAIN OUTCOME MEASURE(S): Stillbirth, prematurity, and early
perinatal mortality. RESULT(S): The delivery rate of multiple births was 31.4%,
and the preterm delivery rate was 25.6%. The prematurity rates in singletons,
twins, and triplets were 9.9%, 56.7%, and 96.6%, respectively. The early
perinatal mortality rate of the entire population was 26.1 per thousand. In the
ejaculated-sperm group, when the sperm was severely defective (group 1), 14
intrauterine deaths occurred (3.1%). In the second and third groups, in which
sperm was moderately defective, there were 2 deaths and 1 death (0.6% and 0.4%),
respectively. The difference between the number of deaths in group 1 vs. groups
2/3 was statistically significant. CONCLUSION(S): The rates of multiple
pregnancies, preterm deliveries, low birth weight, and early perinatal mortality
were higher after ICSI than after natural conception. In the ejaculated-sperm
group, the rate of intrauterine death was higher in the severely defective sperm
group than in the better-quality sperm groups.
PMID- 9757880
TI - Prevalence of Y chromosome microdeletions in oligospermic and azoospermic
candidates for intracytoplasmic sperm injection.
AB - OBJECTIVE: To determine the prevalence and type of Y chromosome microdeletions in
136 consecutively seen intracytoplasmic sperm injection (ICSI) candidates and in
50 consecutively seen azoospermic men attending an infertility clinic. DESIGN:
Controlled clinical study. SETTING: Genetics laboratory and infertility clinic at
a University hospital. PATIENT(S): One hundred eighty-six men who were seen at an
infertility clinic and who were referred to a genetics counseling service for
genetic assessment before ICSI. INTERVENTION(S): Collection of semen and blood
samples. MAIN OUTCOME MEASURE(S): Semen analysis; serum FSH, LH, and T levels;
karyotype analysis; and presence or absence of several single tagged site markers
along the Y chromosome (sY274, sY238, sY276, sY84, sY102, sY143, sY153, sY254,
sY269, sY202, sY158, sY160). RESULT(S): Yq chromosome microdeletions were
detected in 10 (5.4%) of 186 consecutively seen ICSI candidates. The number of
microdeletions was much higher in azoospermic patients (16%; 8 of 50) than in
oligospermic patients (1.5%; 2 of 136). Two of the azoospermic patients with a Yq
microdeletion also had sex chromosome aneuploidy mosaicism. No microdeletions
were detected in 100 consecutively seen fathers who were included as controls.
CONCLUSION(S): The prevalence of Yq microdeletions in the azoospermic group was
much higher than in the oligospermic group and was consistent with the prevalence
of Yq microdeletions detected in other series of azoospermic men in different
geographic areas. All Yq microdeletions found in our patients belong to the AZFc
region, indicating that microdeletions of the AZFa and AZFb regions are
infrequent among oligospermic ICSI candidates or azoospermic males in our
population.
PMID- 9757881
TI - Systemic methotrexate therapy versus laparoscopic salpingostomy in patients with
tubal pregnancy. Part I. Impact on patients' health-related quality of life.
AB - OBJECTIVE: To compare patients' health-related quality of life after systemic
methotrexate therapy versus laparoscopic salpingostomy for tubal pregnancy.
DESIGN: Multicenter randomized clinical trial. SETTING: Departments of obstetrics
and gynecology of six Dutch hospitals. PATIENT(S): Hemodynamically stable
patients with a laparoscopically confirmed unruptured tubal pregnancy without
signs of active bleeding, who were randomly assigned to undergo either systemic
methotrexate therapy or laparoscopic salpingostomy. INTERVENTION(S): Standard
health-related quality of life questionnaires administered before and 2 days, 2
weeks, 4 weeks. and 16 weeks after confirmative laparoscopy. MAIN OUTCOME
MEASURE(S): Health-related quality of life. RESULT(S): Health-related quality of
life was impaired most severely 2 days after confirmative laparoscopy in both
treatment groups and improved during follow-up. Health-related quality of life
was impaired more severely after systemic methotrexate therapy than after
laparoscopic salpingostomy. Medically treated patients had more limitations in
physical functioning, role functioning, and social functioning; had worse health
perceptions, less energy, more pain, more physical symptoms, and a worse overall
quality of life; and were more depressed than surgically treated patients.
CONCLUSION(S): Systemic methotrexate therapy had a more negative impact on
patients' health-related quality of life than did laparoscopic salpingostomy.
This negative impact on patients' health-related quality of life of systemic
methotrexate therapy should be taken into account when deciding on the
appropriate therapy for tubal pregnancy.
PMID- 9757882
TI - Systemic methotrexate therapy versus laparoscopic salpingostomy in tubal
pregnancy. Part II. Patient preferences for systemic methotrexate.
AB - OBJECTIVE: To investigate patient preferences for systemic methotrexate therapy
relative to laparoscopic salpingostomy in the treatment of tubal pregnancy.
DESIGN: Preference assessment in controlled clinical study. SETTING: Four
hospitals and one infertility clinic. PATIENT(S): Forty patients who had been
treated for tubal pregnancy and 40 nonpregnant controls. INTERVENTION(S):
Preference for methotrexate therapy relative to salpingostomy was established
during an interview. Two scenarios were offered for methotrexate therapy: one
with and one without preceding diagnostic laparoscopy. Hypothetical tubal patency
rates after methotrexate therapy were varied in both scenarios until patients
switched in their initial preference. MAIN OUTCOME MEASURE(S): Preference for
systemic methotrexate therapy. RESULT(S): Only a few patients switched in their
initial preference when the tubal patency rate after systemic methotrexate
therapy was varied. Most preferred methotrexate therapy without an increase in
the tubal patency rate in a scenario without preceding diagnostic laparoscopy. A
small group never opted for methotrexate therapy even when it would guarantee a
100% tubal patency rate. CONCLUSION(S): Systemic methotrexate therapy would be
preferred by most patients as part of a completely nonsurgical management
strategy. Tubal patency was a decisive factor for treatment preference in a
minority of patients only.
PMID- 9757883
TI - Transvaginal salpingoscopy: an office procedure for infertility investigation.
AB - OBJECTIVE: To evaluate the feasibility of salpingoscopy as an office procedure
using transvaginal access to the pelvic cavity. DESIGN: Descriptive study.
SETTING: Gynecology office. PATIENT(S): Infertile women with no obvious pelvic
pathology. INTERVENTION(S): Transvaginal Veress needle puncture and peritoneal
distension by saline. MAIN OUTCOME MEASUREMENT(S): Visualization of distal tubal
segment. cannulation, and salpingoscopy. RESULT(S): The fimbriae were visualized
in all patients. Cannulation of the distal tubal segment was achieved without
manipulation of the tube in 20% before ovulation and 55% in the early luteal
phase. CONCLUSION(S): Transvaginal fimbrioscopy and salpingoscopy can be
performed as an office procedure in patients without obvious pelvic pathology. In
combination with hydrolaparoscopy and dye hydrotubation, the technique provides
comprehensive screening of the tuboovarian structures in the early stage of
infertility investigation.
PMID- 9757884
TI - Results of laparoscopic treatments of ovarian endometriomas: laparoscopic ovarian
fenestration and coagulation.
AB - OBJECTIVE: To determine the long-term results of laparoscopic fenestration and
coagulation of ovarian endometriomas and to compare them with the results of
ovarian cystectomy performed by either laparotomy or laparoscopy. DESIGN: Case
control study. SETTING: Two university-affiliated hospitals. PATIENT(S): One
hundred fifty-six premenopausal women with ovarian endometriomas of at least 3 cm
in diameter (stage 3 and 4 endometriosis, revised American Fertility Society
classification). INTERVENTION(S): Laparoscopic ovarian fenestration and
coagulation (group 1, 80 patients); laparoscopic ovarian cystectomy (group 2, 23
patients); and ovarian cystectomy by laparotomy and microsurgical technique
(group 3, 53 patients). MAIN OUTCOME MEASURE(S): Operative findings, recurrence
rate, and cumulative clinical pregnancy rate (PR) over a 36-month follow-up
period. RESULT(S): The mean (+/-SD) time to first pregnancy was significantly
shorter in group 1 (1.4+/-0.2 years) than in group 2 (2.2+/-0.5 years) or group 3
(2.4+/-0.5 years). The difference between the cumulative clinical PR between the
three groups was not statistically significant after 36 months of follow-up. The
difference in the recurrence rate among groups 1, 2, and 3 was not statistically
significant. CONCLUSION(S): Laparoscopic ovarian fenestration and coagulation of
endometriomas leads to faster conception than ovarian cystectomy by laparotomy.
Laparoscopic ovarian fenestration and coagulation of endometriomas is associated
with cumulative clinical PRs and recurrence rates over 36 months that are similar
to those associated with ovarian cystectomy.
PMID- 9757885
TI - Robotically assisted laparoscopic microsurgical uterine horn anastomosis.
AB - OBJECTIVE: To evaluate the feasibility, safety, and sterility issues with regard
to the use of a robotic device to perform uterine horn anastomosis in a live
porcine model. DESIGN: Prospective animal study. SETTING: Landrace-Yorkshire pigs
in a conventional laboratory setting. INTERVENTION(S): Six female pigs underwent
laparoscopic bipolar electrocoagulation of the distal uterine horns. Two weeks
later, the uterine horns were reanastomosed laparoscopically with use of a
robotic system for microsuturing. Necropsy was performed 4 weeks later to assess
postoperative adhesions and anastomosis patency. MAIN OUTCOME MEASURE(S): Tubal
patency; secondary measures were operative time, complications, and surgeon
fatigue. RESULT(S): The mean (+/-SD) total operative time per animal was 170+/-34
minutes including setting up and dismantling the robotic arms. The robot
functioned well with only minor technical problems. All pigs survived both
surgeries with no perioperative complications related to the use of the robot.
Patency was confirmed after completing each anastomosis (12 anastomoses; 100%
patency). Four weeks later, necropsy showed that eight anastomoses were still
patent (67%). Only one pig had bilateral occlusion. Surgeon's fatigue was mild
for each animal study. CONCLUSION(S): Robotic technology can be used safely in
creating laparoscopic microsurgical anastomoses. The robot functioned properly in
a sterile operating room environment. Adequate patency rates were achieved during
the acute phase and at 4-week follow-up. Robotic technology has the potential to
make laparoscopic microsuturing easier.
PMID- 9757886
TI - Growth factor regulation of insulin-like growth factor binding protein secretion
by cultured human granulosa-luteal cells.
AB - OBJECTIVE: To examine the effects of epidermal growth factor (EGF), transforming
growth factor-beta (TGF-beta), and fibroblast growth factor (FGF) on insulin-like
growth factor binding protein (IGFBP) secretion by cultured human granulosa
luteal cells. DESIGN: Granulosa-luteal cells obtained at the time of oocyte
harvest for IVF were cultured in serum-free medium in the presence or absence of
EGF, TGF-beta, or FGF. Conditioned medium then was analyzed by Western ligand
blot and immunoradiometric assays. SETTING: An academic medical center.
PATIENT(S): Women undergoing IVF. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S):
IGFBP-1 secretion. RESULT(S): By Western ligand blot analysis, IGFBP-1 levels
were 1.4-fold to 7.4-fold higher in conditioned medium from cells cultured in the
presence of EGF than in control medium. By immunoradiometric assay, IGFBP-1
levels increased from 1.6 to 9.9 times over control. The TGF-beta had no apparent
effect, and FGF did not consistently stimulate IGFBP-1 secretion. CONCLUSION(S):
The EGF may decrease intrafollicular bioavailable IGF levels by increasing
inhibitory IGFBPs, thereby leading to arrest of follicular development.
Interactions between the EGF and IGF systems may be involved in the processes
governing human ovarian follicle maturation and atresia.
PMID- 9757887
TI - Oxytocin enhances the prolactin response to vasoactive intestinal polypeptide in
healthy women.
AB - OBJECTIVE: To establish whether oxytocin modifies the stimulatory effect of
vasoactive intestinal polypeptide (VIP) on prolactin secretion in healthy women.
DESIGN: Controlled clinical study. SETTING: Healthy women in an academic research
environment. PATIENT(S): Seven healthy women (aged 24-32 years) were tested on
the 22nd day of two consecutive normal menstrual cycles. INTERVENTION(S):
Vasoactive intestinal polypeptide (4 pmol x kg(-1) x min(-1) in 50 mL of normal
saline infused i.v. for 60 minutes) was administered in either the presence or
absence of concurrent treatment with oxytocin (2 IU injected plus 0.07 IU/min
infused for 60 minutes). MAIN OUTCOME MEASURE(S): Serum prolactin levels.
RESULT(S): The administration of VIP induced a significant increase in serum
prolactin levels, with a mean peak response 1.6 times higher than baseline at 45
minutes after injection. In the presence of oxytocin, the prolactin response to
VIP was significantly higher, with a mean peak response 2 times higher than
baseline. CONCLUSION(S): These data suggest that in healthy women, oxytocin
facilitates the regulation of the stimulating effect of VIP on prolactin
secretion.
PMID- 9757888
TI - Follicle-stimulating hormone measured in unextracted urine: a reliable tool for
easy assessment of ovarian capacity.
AB - OBJECTIVE: To determine the presence of FSH in unextracted urine of
perimenopausal women using a microparticle enzyme immunoassay kit on an AxSYM
random access immunoassay analyzer. DESIGN: Controlled descriptive study.
SETTING: A large teaching hospital and infertility clinic. PATIENT(S): Forty
perimenopausal women aged 32-55 years admitted to our clinic for a gynecological
operation. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Mean serum FSH level
and urinary FSH in early-morning urine, in a random void urine sample, and in 24
hour urine on the same day. FSH in urine on the day of excretion and 1 and 4
weeks thereafter, stored under various conditions. FSH in urine before and after
extraction. RESULT(S): The Pearson's correlation coefficient between mean serum
FSH levels and urinary FSH in early morning urine was 0.904, in a random void
0.915, and in 24-hour urine 0.857. Determination of optimal storage conditions
revealed that urine was best kept at 4 degrees C without any additive. The
correlation between FSH in extracted and unextracted urine was 98.9%.
CONCLUSION(S): In perimenopausal women, FSH can be reliably measured in
unextracted urine. The correlation between urinary FSH and a random void urine
sample and mean FSH from a serial serum sample is very high. Urine can be stored
for 4 weeks at 4 degrees C without loss of FSH immunoreactivity.
PMID- 9757889
TI - Expression of the apoptosis-related genes, caspase-1, caspase-3, DNA
fragmentation factor, and apoptotic protease activating factor-1, in human
granulosa cells.
AB - OBJECTIVE: To investigate protein and messenger RNA expression products for a
subset of apoptosis-related genes in human granulosa cells. DESIGN: In vitro
experiment. SETTING: Department of Obstetrics, Gynecology, and Reproductive
Biology, Brigham and Women's Hospital, Harvard Medical School, Boston,
Massachusetts. PATIENT(S): Women undergoing oocyte retrieval for IVF after
ovulation induction with gonadotropins. INTERVENTION(S): Granulosa cells were
isolated from follicular aspirates after oocyte removal. MAIN OUTCOME MEASURE(S):
Reverse transcription polymerase chain reaction and Western blotting for
apoptosis-related gene products. RESULT(S): The expression of caspase-1, caspase
3, DNA fragmentation factor, and apoptotic protease activating factor-1, which
are intermediate molecules in phylogenetically conserved apoptotic pathways, was
demonstrated in granulosa cells from patients undergoing IVF. Moreover, proforms,
but not activated enzymes, for both caspase-1 and caspase-3 were observed.
CONCLUSION(S): Granulosa cells from patients undergoing IVF have intrinsic
apoptotic machinery that could be activated for tissue remodeling.
PMID- 9757890
TI - Interleukin-1beta and interleukin-1alpha may affect the implantation rate of
patients undergoing in vitro fertilization-embryo transfer.
AB - OBJECTIVE: To investigate whether interleukin-1beta (IL-1beta) and interleukin
1alpha (IL-1alpha) affect the implantation rate of patients undergoing IVF-ET.
DESIGN: Follicular fluid and serum were obtained on the day of hCG
administration, the day of oocyte retrieval, and the day of embryo transfer.
SETTING: Cellular immunology laboratory in a research institute, a high
technology IVF unit in a medical center, and a university hospital. PATIENT(S):
Thirty-three women who were undergoing IVF-ET. MAIN OUTCOME MEASURE(S): IL-1beta
and IL-1alpha were measured by specific ELISA and their levels were correlated
with the implantation rate. RESULT(S): Classification of IVF-ET patients
according to their implantation rate revealed significantly higher amounts of
follicular fluid IL-1beta in the implantation versus nonimplantation cycles
(68.5+/-24.6 pg/mL versus 20.5+/-13.4 pg/mL); The difference between the level of
IL-1alpha in the two groups was not statistically significant(11.6+/-5.1 pg/mL
versus 7.3+/-1.9 pg/mL). In parallel, systemic FSH/hMG-dependent IL-1beta and IL
1alpha production was observed in implantation cycles but not in nonimplantation
cycles. Statistically significant IL-1beta and IL-1alpha production was observed
after administration of hCG. CONCLUSION(S): Gonadotropins used during IVF-ET
induce local and systemic production of IL-1beta and IL-1alpha. In addition, the
implantation rate for IVF-ET patients who have detectable serum concentrations of
IL-1beta and IL-1beta on the day of hCG administration could be higher than the
rate for IVF-ET patients who do not have detectable concentrations of these
cytokines.
PMID- 9757891
TI - Changes in vascular endothelial growth factor levels and the risk of ovarian
hyperstimulation syndrome in women enrolled in an in vitro fertilization program.
AB - OBJECTIVE: To evaluate plasma and follicular fluid levels of vascular endothelial
growth factor (VEGF) in women undergoing controlled ovarian hyperstimulation to
establish the possible role of this growth factor as a predictive marker of
ovarian hyperstimulation syndrome (OHSS). DESIGN: Prospective observational
study. SETTING: University hospital infertility unit. PATIENT(S): Fifteen women
at risk of OHSS and 15 controls. INTERVENTION(S): An IM injection of hCG was
administered; plasma and follicular fluid samples were collected 34-38 hours
after administration of hCG. MAIN OUTCOME MEASURE(S): VEGF levels in plasma and
in follicular fluid. RESULT(S): VEGF levels increased after hCG administration in
the patients at risk of developing OHSS and in those who developed OHSS. Further,
on the day of the oocyte retrieval the increase in the VEGF levels in the plasma
of the patients who developed OHSS was statistically significant compared with
the increase in the levels in the women who did not. On the same day, the levels
of VEGF in follicular fluid were 10 times greater than those in plasma.
CONCLUSION(S): Plasma levels of VEGF peak after hCG administration and are
related to the risk of developing OHSS.
PMID- 9757892
TI - No evidence of the inactivating mutation (C566T) in the follicle-stimulating
hormone receptor gene in Brazilian women with premature ovarian failure.
AB - OBJECTIVE: To investigate the presence of FSH receptor gene mutations in women
with premature ovarian failure (POF). DESIGN: Clinical and molecular studies.
SETTING: Research laboratory in a university setting. PATIENT(S): Fifteen 46,XX
women with POF and 42 normal fertile controls. INTERVENTION(S): Exon 7 was
amplified and digested with BsmI to screen for the previously described
inactivating mutation C566T. Exon 10 was screened for mutations by denaturing
gradient gel electrophoresis and direct sequencing. MAIN OUTCOME MEASURE(S):
Polymerase chain reaction followed by restriction enzyme analysis, denaturing
gradient gel electrophoresis, and direct sequencing. RESULT(S): No inactivating
mutations were identified in exons 7 and 10 of the FSH receptor gene in women
with familial or sporadic POF. Exon 10 had two polymorphisms, G919A and G2039A,
whose allelic frequencies were 46.7% and 56.6%, respectively, in women with POF.
The allelic frequency of both polymorphisms was 59.5% in normal fertile controls.
CONCLUSION(S): No inactivating mutations in exons 7 and 10 of the FSH receptor
gene were identified in Brazilian women with POF. A high frequency of two
polymorphisms that are in linkage disequilibrium was found in exon 10 of this
gene.
PMID- 9757893
TI - Lateral cervical displacement is associated with endometriosis.
AB - OBJECTIVE: To report on a series of cases of lateral cervical displacement and
uterosacral ligament scarring associated with endometriosis. DESIGN: Case series.
SETTING: Academic medical center. PATIENT(S): Three nulliparous women with
chronic pelvic pain, lateral cervical displacement, and uterosacral nodularity.
INTERVENTION(S): Physical examination to evaluate for lateral cervical
displacement. Laparoscopic surgery to evaluate for endometriosis and uterosacral
ligament involvement. MAIN OUTCOME MEASURE(S): Displacement of the entire cervix
lateral to the midline of the vagina. Presence of endometriosis on the affected
uterosacral ligament. RESULT(S): All three patients had lateral cervical
displacement and implants of endometriosis and scarring on the uterosacral
ligament ipsilateral to the displaced cervix. CONCLUSION(S): In women with pelvic
pain, lateral cervical displacement due to uterosacral scarring may be a physical
finding associated with endometriosis.
PMID- 9757894
TI - Stenosis of the external cervical os: an association with endometriosis in women
with chronic pelvic pain.
AB - OBJECTIVE: To report a simple technique for diagnosing stenosis of the external
cervical os and to evaluate an association between stenosis of the external
cervical os and endometriosis in women with chronic pelvic pain. DESIGN: Case
series. SETTING: Academic medical center. PATIENT(S): Twenty-five women with
chronic pelvic pain and stenosis of the external cervical os. INTERVENTION(S):
Measurement of the diameter of the external cervical os. MAIN OUTCOME MEASURE(S):
Association between cervical stenosis and surgically documented endometriosis in
women with chronic pelvic pain. RESULT(S): Endometriosis was visually documented
at surgery for 24 of 25 women with chronic pelvic pain and stenosis of the
external cervical os. CONCLUSION(S): Endometriosis is a common finding in women
with both stenosis of the external cervical os and chronic pelvic pain.
PMID- 9757895
TI - A randomized comparison of the methods of sperm preparation for intrauterine
insemination.
AB - OBJECTIVE: To compare the effectiveness of three methods of sperm preparation for
IUI during superovulation of infertile women. DESIGN: Randomized assignment of
one of three sperm preparation methods. SETTING: University infertility practice.
PATIENT(S): Infertile couples undergoing superovulation and IUI. INTERVENTION(S):
The method of preparation of sperm for IUI during superovulation was assigned
randomly to double centrifugation, multiple-tube swim-up, or Percoll density
gradient. MAIN OUTCOME MEASURE(S): Total number and percent recovery of motile
sperm, percent of recovered sperm with normal morphology, and cycle fecundity.
RESULT(S): No method of sperm preparation provided better cycle fecundity than
the others despite differences in sperm recovery. CONCLUSION(S): Double
centrifugation, multiple-tube swim-up, and Percoll density gradient sperm
preparation for IUI yield similar cycle fecundity rates.
PMID- 9757896
TI - Spermatozoa with chromosomal abnormalities may result in a higher rate of
recurrent abortion.
AB - OBJECTIVE: To determine whether sperm aneuploidy can lead to abortion. DESIGN:
Clinical study. SETTING: Couples with reproductive problems evaluated in a
private diagnostic laboratory. PATIENT(S): Two men whose wives had histories of
multiple abortions. INTERVENTION(S): Whole and Percoll-processed semen samples
were analyzed. MAIN OUTCOME MEASURE(S): The results of fluorescence in situ
hybridization. RESULT(S): Aneuploidy rates in Percoll-processed samples were
higher than those found in whole specimens. Aneuploid spermatozoa also displayed
greater motility. CONCLUSION(S): Sperm aneuploidy should be studied before and
after Percoll capacitation in all couples with unexplained infertility.
PMID- 9757897
TI - Birth after cryopreservation of immature oocytes with subsequent in vitro
maturation.
AB - OBJECTIVE: To establish the clinical feasibility of using cryostored germinal
vesicle oocytes for IVF and ET. DESIGN: Case report. SETTING: Private infertility
clinic. PATIENT(S): A 28-year-old woman with tubal infertility undergoing IVF
therapy. INTERVENTION(S): Oocytes collected after ovarian stimulation were frozen
without insemination or were inseminated, fertilized, and frozen as cleavage
stage embryos. No fresh oocyte or embryo transfer was undertaken. All oocytes
were thawed, and those that survived were used for IVF-ET. MAIN OUTCOME
MEASURE(S): Oocyte cryosurvival, in vitro maturation, fertilization, embryo
development, and pregnancy outcome. RESULT(S): None of 16 mature oocytes survived
thawing; however, three of 13 germinal vesicle oocytes survived. After 30 hours
in vitro maturation two oocytes had matured and underwent intracytoplasmic sperm
injection with the partner's sperm. Both fertilized normally and were transferred
to the patient. The woman delivered an apparently healthy female infant at 40
weeks. CONCLUSION(S): This case report proves the feasibility if not the
efficiency of using immature oocytes for cryostorage, coupling both
cryopreservation and in vitro maturation.
PMID- 9757898
TI - Does pelvic magnetic resonance imaging differentiate among the histologic
subtypes of uterine leiomyomata?
AB - OBJECTIVE: To evaluate if pelvic magnetic resonance imaging (MRI) is reliable for
differentiating leiomyoma subtypes. DESIGN: Prospective study. SETTING: Academic
center. PATIENT(S): Forty-five patients underwent MRI before surgery for
leiomyomata. INTERVENTION(S): One radiologist blinded to patient history and
histologic diagnosis recorded the MRI characteristics and classification of the
largest leiomyoma. MAIN OUTCOME MEASURE(S): Comparison of MRI and histologic
diagnoses. RESULT(S): Leiomyoma subtypes were diagnosed accurately by MRI in 69%
of cases. Magnetic resonance imaging had a 95% sensitivity and 72% specificity
for diagnosing an uncomplicated leiomyoma and a 10% sensitivity and 100%
specificity for a cellular leiomyoma. For cystic leiomyomata, the sensitivity was
80% and specificity was 98%, and for hemorrhagic leiomyomata, 100% and 86%,
respectively. Magnetic resonance imaging correctly diagnosed all malignant tumors
and did not incorrectly diagnose a leiomyoma as a leiomyosarcoma in any case. Ill
defined MRI margins were significantly more likely to be leiomyosarcoma, whereas
well-defined margins were characteristic of benign lesions. Hemorrhagic
leiomyomata were significantly more likely to be hyperintense on T1-weighted
images than other subtypes. CONCLUSION(S): Although MRI is only fairly accurate
in differentiating the subtypes of benign uterine smooth muscle tumors, signal
intensities and margin characteristics are useful to distinguish accurately
benign from malignant tumors.
PMID- 9757900
TI - Pelvic endometriosis--the same or different entities in disguise?
PMID- 9757899
TI - Pelvic endometriosis--the same or different entities in disguise?
PMID- 9757901
TI - Pelvic endometriosis--the same or different entities in disguise?
PMID- 9757902
TI - Pelvic endometriosis--the same or different entities in disguise?
PMID- 9757903
TI - Benediction for diagnostic laparoscopy in pelvic pain syndromes and neurotic
genes?
PMID- 9757904
TI - Role of transvaginal ultrasonography in the diagnosis of ectopic pregnancy.
PMID- 9757905
TI - Success rates of methotrexate in ectopic pregnancy?
PMID- 9757906
TI - Success rates of methotrexate in ectopic pregnancy?
PMID- 9757907
TI - The Book of Samuel, mice, leptin, pheromones, and anorexia nervosa.
PMID- 9757908
TI - A negative study with power?
PMID- 9757909
TI - Immunoregulation by CD4 T cells in the induction of specific immunological
unresponsiveness to alloantigens in vivo: evidence for a reduction in the
frequency of alloantigen-specific cytotoxic T cells in vitro.
AB - Donor-specific unresponsiveness to allogeneic cardiac allografts in mice can be
induced by the combined pretreatment with donor alloantigen and anti-CD4 antibody
(anti-CD4+DST). We have investigated whether the induction of unresponsiveness in
this model is due to the presence of T cells that regulate immune responsiveness
towards the allograft. First, we analysed the functional characteristics of
splenocytes from pretreated mice at the time of transplantation. A significant
reduction in the frequency of donor specific cytotoxic precursor was found only
after the anti-CD4+DST treatment. Next, we designed an in vitro assay to identify
the phenotype of the splenocyte population responsible. CD4+ and CD4- fractions
were purified from mice treated with anti-CD4+DST or anti-CD4 alone (controls) by
cell sorting. Interestingly, only the addition of CD4+ cells from anti-CD4+DST
treated mice resulted in a selective reduction and a bimodal distribution in the
donor specific CTLp response, indicating the presence of a regulatory population.
CD4+ cells from controls did not have this effect. These in vitro findings were
substantiated by adoptive transfer experiments in vivo. These data demonstrate
that CD4+ cells with the ability to regulate immune responsiveness to a cardiac
allograft are present at the time of transplantation following pretreatment with
donor alloantigen in combination with anti-CD4.
PMID- 9757910
TI - The presentation of self and allogeneic MHC peptides to T lymphocytes.
AB - The presentation of donor-derived MHC peptides by recipient APCs to T cells is an
essential component of the rejection of allografts (indirect allorecognition).
Initial alloreactive T cell response is confined to a few well processed and
presented dominant determinants on donor MHC. However, during long-term graft
rejection, T cell response spreads to formerly poorly presented cryptic
allogeneic MHC peptides. This phenomenon is likely to play an important role in
the amplification and the perpetuation of the rejection process. Additionally, we
present evidence that T cell repertoire selection to allogeneic MHC peptides is
acquired via recognition of self-MHC peptides presented in the thymus during
ontogeny. Supporting this view, we have shown that indirect alloresponses can
lead to self-T cell tolerance breakdown to cross-reactive determinants on self
MHC molecules or alternatively that sensitization of recipients to self-MHC
peptides can lead to accelerated graft rejection. It is therefore essential to
determine the factors which govern the processing and presentation of self and
allogeneic MHC molecules and to elucidate the mechanisms regulating subsequent T
cell responses in order to design antigen-specific based immune therapies in
transplantation.
PMID- 9757911
TI - Characterization of self-glutamic acid decarboxylase 65-reactive CD4+ T-cell
clones established from Japanese patients with insulin-dependent diabetes
mellitus.
AB - To investigate autoimmunity to glutamic acid decarboxylase (GAD) 65 in Japanese
patients with insulin-dependent diabetes mellitus (IDDM, type I diabetes), we
established seven CD4+ T-cell clones, by stimulating peripheral blood mononuclear
cells (PBMC) of six IDDM patients, using a mixture of overlapping human GAD65
peptides. No GAD65 autoreactive T-cell clones were evidenced in four healthy
controls. Specificities of T-cell clones were as follows: (a) two clones specific
to GAD65 p111-131 (residue 111 to 131) + DR53 (DRB4*0103); (b) one clone specific
to GAD65 p413-433 + DR1 (DRB1*0101); (c) two clones specific to GAD65 p200-217 +
either DR9 (DRB1*0901) or DR8 (DRB1*0802); and (d) two clones specific to GAD65
p368-388 + DP2 (DPA1*01 or 0201-DPB1*0201). Two DR53-restricted and one DR1
restricted T-cell clones, responded to a recombinant human GAD65 protein, and
showed cytotoxicity against B lymphoblastoid cell lines pre-pulsed with the
peptides. Six T-cell clones exhibited the Th1-like phenotype. Interestingly, two
DR53-restricted T-cell clones killed a Fas-deficient B lymphoblastoid cell line,
thereby indicating that cytotoxicity was not completely dependent on a Fas-Fas
ligand interaction. Thus, the T-cell epitopes were mapped in a limited portion of
GAD65 protein, with a tendency to be restricted by disease-associated HLA-DR, but
not DQ molecules.
PMID- 9757912
TI - Multiple epitopes of HLA-DRB1*0411 are recognized by T-cell clones originated
from individuals carrying other DR4 subtypes.
AB - HLA polymorphism dictates the binding and recognition of specific peptides,
leading to variations in individual immune responses and may contribute to
autoimmune disorders and outcome in organ transplantation. We have studied the
molecular basis for the cellular recognition of DRB1*0411 in individuals carrying
other sequence-related DR4-alleles by characterization of T-cell clones (TLC). A
set of 166 TLC were raised by priming cells from DRB1*0401,0402 and
DRB1*0405,0901 individuals and 52 of them recognized DRB1*0411. Five distinct
patterns of T-cell allorecognition were found: DRB1*0411 alone, DRB1*0411 and
0405, DRB1*0411 and 0406, DRB1*0411 and 0407 and DRB1*0411, 0406 and 0407,
depending on responder phenotypes and epitopes recognized by their T cells. A
stretch of 30 amino acids on DRB1*0411 from positions 57 to 86 behaves as a
functional domain and residues S57, R71, E74 and V86 seem to be crucial in
forming immunogenic determinants recognized by these TLC. The knowledge of shared
amino acid residues between closely related DR4 alleles, which show similar
patterns of recognition by T cells could also be useful in the selection of
prospective donors for clinical transplantation of solid organs or bone marrow.
PMID- 9757913
TI - Tumor necrosis factor locus: genetic organisation and biological implications.
AB - TNF genes determine strength, effectiveness, and duration of local and systemic
inflammatory reactions, as well as repair and recovery from infectious and toxic
agents. Multiple pro- and anti-inflammatory activities of TNF factors are
conditioned by their profound effects on metabolism of many cell types, their
activation state, cell survival and others. TNF genes show strong linkage
disequilibrium with HLA class I and class II genes and with other genes in the
MHC region relevant to immuneregulation. Structural or regulatory defects in TNF
genes may contribute to pathogenesis of MHC associated diseases especially those
with inflammatory and autoimmune components.
PMID- 9757914
TI - HLA-DR and -DQ associations with melioidosis.
AB - Melioidosis is an important infectious disease of southeast Asia caused by an
intracellular bacterium, Burkholderia pseudomallei. Cellular immunity is
postulated to play important roles in immunity to melioidosis that may influence
the severity and clinical outcome of the disease. The present study was
undertaken to investigate possible associations of melioidosis with HLA class II
alleles. HLA typing of HLA-DRB1, -DQA1, and -DQB1 was performed using polymerase
chain reaction and sequence-specific oligonucleotide hybridization (PCR-SSO).
Seventy-nine melioidosis patients and 105 healthy, ethnically and geographically
matched controls were studied. Among 24 DRB1 alleles, 7 DQA1 alleles, and 13 DQB1
alleles identified in this population, an association with melioidosis was
observed with DRB1*1602 which was increased in melioidosis patients (10.1%)
compared to normal controls (4.8%), p = 0.047 (odds ratio (OR) = 2.25). In
addition, significant increase of DRB1*1602 allele frequency and decrease of
DQA1*03 were also observed in septicemic melioidosis patients, the most severe
form of the disease (p = 0.01, OR = 3.10; and p = 0.047, respectively).
Furthermore, a trend of association of DRB1*0701, DQA1*0201, and DQB1*0201 with
relapse cases of melioidosis was also noted. In contrast, no HLA association was
observed in localized melioidosis or melioidosis with diabetes mellitus. These
findings provide the suggestive evidence of an immunogenetic basis of certain
aspects of melioidosis.
PMID- 9757915
TI - Assignment of HLA-antigens in CREGs facilitates the detection of acceptable
mismatches in highly sensitized patients.
AB - The purpose of this study was to investigate whether in highly sensitized
patients (HSPs) the acceptable HLA-A and -B mismatches (AMs) can be predicted on
the basis of patients' HLA-phenotype. To this affect, 1000 historical serum
samples obtained from 50 HSPs (PRA > 60%), panel reactive antibodies (PRA) value
and the specificity of class I anti-HLA-antibodies were detected by two
techniques in parallel: An anti-human globulin augmented cytotoxicity (AHG-CDC)
and an Elisa technique. Thereafter, class I HLA-antigens of the nonreactive cells
in the screening panel and class I HLA-antigens of the patients were assigned to
CREGs. The AMs for each one of the patients were detected using a separate cell
panel, which was prepared in a way to include almost all the HLA-antigens
belonging to the CREGs of the patients as well as to those of the nonreactive
cells in the screening panel. It was found that the AMs in HSPs, detected with
this protocol were more, compared to those we usually detect using only the HLA
antigens of the nonreactive cells in the screening panel (up to 8 versus 2-5).
Both, the definitively detected AMs, and the HLA-specificities of the nonreactive
cells of the screening panel belonged to the same CREGs. These CREGs were
equivalent to the CREGs of class I HLA-phenotypes of each patient. The data
presented in this paper introduce a new, rapid and easier way for the detection
of AMs in HSPs. According to this proposed protocol, the assignment of patients'
standard class I private HLA-phenotypes in CREGs, not only greatly facilitates
the detection of AMs, but the detected AMs are also in fact significantly more
than those determined by the conventional methodology. We have also confirmed
that the majority of antibodies induced by HLA alloimmunization are directed
against mismatched shared or public group epitopes CREGs. Moreover, we have
confirmed that prospective matching for major CREGs would be feasible on a
national level and would not significantly prolong waiting time, which could
result in a significant augmentation of the potential donor pool.
PMID- 9757916
TI - Saliva as DNA source for HLA typing.
PMID- 9757917
TI - Gastric tonometry, tissue hypoxia and MSOF. Is there a link?
PMID- 9757920
TI - Comparison of air tonometry with gastric tonometry using saline and other
equilibrating fluids: an in vivo and in vitro study.
AB - OBJECTIVE: 1) To compare saline gastric tonometry monitoring with air tonometry
(Tonocap) in a group of general ICU patients. 2) An in vitro investigation of the
performance of other fluids used in gastric tonometry and to assess the effects
of variation of temperature and carbon dioxide concentration within the range
encountered in clinical use. DESIGN: a) A prospective, observational study in ICU
patients b) A comparative laboratory study. SETTING: The general Intensive Care
Unit (ICU) and the laboratory at Leeds General Infirmary. PATIENTS AND
PARTICIPANTS: Nine patients in the general ICU with severe sepsis or septic
shock. MEASUREMENTS AND RESULTS: In vivo comparison of saline and air tonometry
demonstrated a difference between the two techniques. Bland & Altman analysis
showed a mean bias in the measurement of gastric PCO2 of 1.88 kPa with a
precision of 1.22 kPa, with saline giving the lower result. In vitro, saline, air
(Tonocap), gelatin and heparinised blood were used, at temperatures of 33-42
degrees C and at carbon dioxide concentrations of 4-8 kPa. While gelatin and
blood gave unpredictable results, dependent on temperature and carbon dioxide
concentration, air tonometry gave highly reproducible results. A consistent bias
between the results with saline and air tonometry was seen over the range of
temperatures and carbon dioxide (CO2) concentrations studied. The mean bias was
0.85 kPa with a precision of 0.40 kPa, saline consistently giving lower results.
CONCLUSIONS: There are clinically significant differences in values for gastric
mucosal PCO2 measured by air tonometry and saline tonometry both in vivo and in
vitro.
PMID- 9757919
TI - Gastric intramucosal pH-guided therapy in patients after elective repair of
infrarenal abdominal aneurysms: is it beneficial?
AB - OBJECTIVE: To determine if gastric intramucosal pH (pHi)-guided therapy reduces
the number of complications and length of stay in the intensive care unit (ICU)
or the hospital after elective repair of infrarenal abdominal aortic aneurysms.
DESIGN: Prospective, randomized study. SETTING: Surgical intensive care unit
(SICU) of a University Hospital. PATIENTS: Fifty-five consecutive patients
randomized to group 1 (pHi-guided therapy) or to group 2 (control).
INTERVENTIONS: Patients of group 1 with a pHi of lower than 7.32 were treated by
means of a prospective protocol in order to increase their pHi to 7.32 or more.
MEASUREMENTS AND RESULTS: pHi was determined in both groups on admission to the
SICU and thereafter at 6-h intervals. In group 2, the treating physicians were
blinded for the pHi values. Complications, APACHE II scores, duration of
endotracheal intubation, fluid and vasoactive drug treatment, treatment with
vasoactive drugs, length of stay in the SICU and in the hospital and hospital
mortality were recorded. There were no differences between groups in terms of the
incidence of complications. We found no differences in APACHE II scores on
admission, the duration of intubation, SICU or hospital stay, or hospital
mortality. In the two groups the incidence of pHi values lower than 7.32 on
admission to the SICU was comparable (41% and 42% in groups 1 and 2,
respectively). Patients with pHi lower than 7.32 had more major complications
during SICU stay (p < 0.05), and periods more than 10 h of persistently low pHi
values (< 7.32) were associated with a higher incidence of SICU complications (p
< 0.01). CONCLUSIONS: Low pHi values (< 7.32) and their persistence are
predictors of major complications. Treatment to elevate low pHi values does not
improve postoperative outcome. Based on these data, we cannot recommend the
routine use of gastric tonometers for pHi-guided therapy in these patients.
Further studies are warranted to determine adequate treatment of low pHi values
that results in beneficial effects on the patient's postoperative course and
outcome.
PMID- 9757918
TI - Applications of thrombolytic therapy.
PMID- 9757921
TI - Physiologic evaluation of non-invasive pressure support ventilation in trauma
patients with acute respiratory failure.
AB - OBJECTIVE: To investigate the effectiveness of noninvasive (face mask) versus
invasive (endotracheal tube) equal pressure values on blood gases and respiratory
pattern and to evaluate the feasibility of using mask ventilation after the short
term physiologic study. DESIGN: Open, prospective, physiologic study and
uncontrolled clinical study. SETTING: Intensive care unit of a trauma center.
PATIENTS: 22 intubated trauma patients were studied. INTERVENTIONS: Patients were
intubated and ventilated in a pressure support mode (IPSV) of 13.5 +/- 1.5 cmH2O
and a post end-expiratory pressure (PEEP) of 5.8 +/- 2.57 cmH2O. After a T-piece
trial to assess patient's ability to breath spontaneously, patients were switched
over to noninvasive pressure support (NIPSV). The pressure levels were set as
during IPSV. Blood gases and respiratory parameters were measured during IPSV,
during the T-piece trial, and after 1 h of NIPSV. After the physiologic study,
all patients were asked if they wished to continue on NIPSV. The patient's
subjective compliance with IPSV and NIPSV was measured by means of an arbitrary
score. A successful outcome was defined as no need for reintubation. MEASUREMENTS
AND RESULTS: IPSVand NIPSV showed no statistical differences for blood gas and
respiratory parameters by using the same values of PSV (13 +/- 5 vs 12.8 +/- 1.7
cmH2O, NS) and PEEP (5.8 +/- 2.5 and 5.2 +/- 2.2 cmH2O NS). The median length of
time on NIPSV was 47 h (range 6 to 144). All patients wished to continue on
NIPSV, but 9 patients (40.9%) were reintubated after 54 +/- 54 h. Six of them
died after 36 +/- 13 days while still on mechanical ventilation. There was no
statistically significant difference in compliance score between IPSVand NIPSV.
CONCLUSIONS: NIPSV is comparable to IPSV in terms of blood gases and respiratory
pattern. The clinical uncontrolled study indicates that NIPSV could be used in
selected trauma patients.
PMID- 9757922
TI - An investigation into the effects of midazolam and propofol on human respiratory
cilia beat frequency in vitro.
AB - OBJECTIVE: Patients in intensive care are known to be prone to both upper and
lower respiratory tract infection. Respiratory mucus forms a barrier to
infection. Mucus transport rate (MTR) depends upon both the physical properties
of mucus and the action of respiratory cilia. Patients undergoing anaesthesia are
known to have a reduced MTR that may be related to a depressant effect on cilia
beat frequency (CBF) by anaesthetic drugs. The aim of this study was to
investigate the effects of two commonly used intensive care sedative agents,
midazolam and propofol, on CBF using human nasal turbinate explants in vitro.
DESIGN: We exposed ciliated tissue from human nasal turbinate explants to
midazolam and propofol in supraclinical concentrations (20 microM midazolam and
70 microM propofol) in a controlled and blinded manner for 90 min and measured
CBF by the transmitted light technique. RESULTS: After 90 min, mean (SEM) CBF in
the group exposed to midazolam and its control group were 13.0 (0.2) Hz and 12.9
(0.3) Hz, respectively. Mean (SEM) CBF in the group exposed to propofol was 13.6
(0.4) Hz and in the control group the value was 12.0 (0.6) Hz. There was no
significant change in CBF (midazolam: p = 0.21, propofol: p = 0.31, MANOVA for
repeated measures). CONCLUSIONS: We have found no effect of midazolam or propofol
in supra-clinical concentrations upon CBF in human turbinate explants after a 90
min exposure. This contrasts with previous work that has shown a depressant
effect of inhalational anaesthetic agents on CBF.
PMID- 9757923
TI - Effect of enteral versus parenteral feeding on hepatic blood flow and steady
state propofol pharmacokinetics in ICU patients.
AB - OBJECTIVE: The main objective of this study was to evaluate the effect of
switching from parenteral to enteral feeding on liver blood flow and propofol
steady-state blood concentrations in patients in the intensive care unit (ICU).
DESIGN AND PATIENTS: Steady-state blood concentrations of propofol were measured
in eight ICU patients before (on days D -3, D -2, and D -1) and after (on days D
+ 1, D + 2, and D + 3) switching from parenteral to enteral feeding (on day DO).
All patients received a continuous intravenous infusion of propofol (4.5 mg x kg(
1) x h(-1)) from several days before the start of the study, continuing
throughout the experimental period. Hepatic blood flow was estimated by measuring
steady-state D-sorbitol hepatic clearance. RESULTS: Hepatic blood flow was high
and was not affected by switching from parenteral to enteral feeding: 33 +/- 8 ml
x min(-1) x kg(-1) (mean +/- SD) and 33 +/- 10 ml min(-1) x kg(-1) on D -3 and D
1, respectively, as compared to 37 +/- 11 ml x min(-1) kg(-1) and 34 +/- 8 ml x
min(-1) x kg(-1) on days D + 1 and D + 3, respectively. Systemic clearance of
propofol was much higher than liver blood flow with average values on the six
observation days ranging from 74.0 to 81.2 ml x min(-1) x kg(-1) and was not
affected by switching from parenteral to enteral feeding. CONCLUSIONS: Liver
blood flow and systemic clearance of propofol were not affected by switching from
parenteral to enteral feeding in the eight ICU patients studied. Extrahepatic
clearance accounted for at least two thirds of the overall systemic clearance of
propofol.
PMID- 9757924
TI - Patterns of neurophysiological abnormality in prolonged critical illness.
AB - OBJECTIVE: To describe the various patterns of neurophysiological abnormalities
which may complicate prolonged critical illness and identify possible
aetiological factors. DESIGN: Prospective case series of neurophysiological
studies, severity of illness scores, organ failures, drug therapy and hospital
outcome. Some patients also had muscle biopsies. SETTING: General intensive care
unit (ICU) in a University Hospital. PATIENTS: Forty-four patients requiring
intensive care unit stay of more than 7 days. The median age was 60 (range 27-84
years), APACHE II score 19 (range 8-33), organ failures 3 (range 1-6), and
mortality was 23%. RESULTS: Seven patients had normal neurophysiology (group I),
4 had a predominantly sensory axonal neuropathy (group II), 11 had motor
syndromes characterised by markedly reduced compound muscle action potentials and
sensory action potentials in the normal range (group III) and 19 had combinations
of motor and sensory abnormalities (group IV). Three patients had abnormal
studies but could not be classified into the above groups (group V). All patients
had normal nerve conduction velocities. Electromyography revealed evidence of
denervation in five patients in group III and five in group IV. There was no
obvious relationship between the pattern of neurophysiological abnormality and
the APACHE II score, organ failure score, the presence of sepsis or the
administration of muscle relaxants and steroids. A wide range of histological
abnormalities was seen in the 24 patients who had a muscle biopsy; there was no
clear relationship between these changes and the neurophysiological
abnormalities, although histologically normal muscle was only found in patients
with normal neurophysiology. Only three of the eight patients from group III in
whom muscle biopsy was performed had histological changes compatible with
myopathy. CONCLUSIONS: Neurophysiological abnormalities complicating critical
illness can be broadly divided into three types -- sensory abnormalities alone, a
pure motor syndrome and a mixed motor and sensory disturbance. The motor syndrome
could be explained by an abnormality in the most distal portion of the motor
axon, at the neuromuscular junction or the motor end plate and, in some cases, by
inexcitable muscle membranes or extreme loss of muscle bulk. The mixed motor and
sensory disturbance which is characteristic of 'critical illness polyneuropathy'
could be explained by a combination of the pure motor syndrome and the mild
sensory neuropathy. More precise identification of the various neurophysiological
abnormalities and aetiological factors may lead to further insights into the
causes of neuromuscular weakness in the critically ill and ultimately to measures
for their prevention and treatment.
PMID- 9757925
TI - Risk factors for acute renal failure in trauma patients.
AB - OBJECTIVE: To elucidate the risk factors for the development of acute renal
failure (ARF) in severe trauma. DESIGN: Prospective observational study. SETTING:
A general intensive care unit (ICU) of a university hospital. PATIENTS: A cohort
of 153 consecutive trauma patients admitted to the ICU over a period of 30
months. RESULTS: Forty-eight (31%) patients developed ARF. They were older than
the 105 patients without ARF (p = 0.002), had a higher Injury Severity Score
(ISS) (p < 0.001), higher mortality (p < 0.001), a more compromised neurological
condition (p = 0.007), and their arterial pressure at study entry was lower (p =
0.0015). In the univariate analysis, the risk of ARF increased by age, ISS > 17,
the presence of hemoperitoneum, shock, hypotension, or bone fractures,
rhabdomyolysis with creatine phosphokinase (CPK) > 10000 IU/l, presence of acute
lung injury requiring mechanical ventilation, and Glasgow Coma Score < 10. Sepsis
and use of nephrotoxic agents were not associated with an increased risk of ARF.
In the logistic model, the need for mechanical ventilation with a positive end
expiratory pressure > 6 cm H2O, rhabdomyolysis with CPK > 10000 IU/l, and
hemoperitoneum were the three conditions most strongly associated with ARF.
CONCLUSIONS: The identified risk factors for post-traumatic acute renal failure
may help the provision of future strategies.
PMID- 9757926
TI - The clinical relevance of the Waterlow pressure sore risk scale in the ICU.
AB - OBJECTIVE: To evaluate whether the Waterlow pressure sore risk (PSR) scale has
prognostic significance for intensive care patients. DESIGN: A prospective study.
SETTING: The surgical intensive care unit (ICU) of the University Hospital
Rotterdam. PATIENTS: Data were evaluated from 594 patients who had been admitted
to the ICU during the year 1994. METHODS AND RESULTS: Each patient was assessed
daily with respect to their Waterlow PSR score and the development of pressure
sores in the sacral region. Actuarial statistical methods were used to analyse
the predictive value of the risk score. When a patient had a Waterlow PSR score >
25 on admission, the risk of developing a pressure sore was significantly
increased compared to patients with a PSR score < 25. After admission, the daily
Waterlow PSR scores obtained were significantly associated with the risk of
developing a pressure sore. For each additional point this risk increased by 23%
(95% confidence interval 17 to 28%). CONCLUSIONS: The Waterlow PSR scale provides
the medical and nursing staff at an early stage with reliable information about
the risk patients have in developing a pressure sore.
PMID- 9757927
TI - Tracing best PEEP by applying PEEP as a RAMP.
AB - OBJECTIVE: The aim of this study was to show the feasibility of a slow,
continuously increasing level of positive end-expiratory pressure (PEEP) (ramp
manoeuvre) in selecting best PEEP and to evaluate whether best PEEP, as defined
by maximal oxygen transport, coincides with best systemic arterial oxygenation or
best compliance. DESIGN: In 11 anaesthetized piglets, PEEP was increased between
0 cmH2O (zero end-expiratory pressure; ZEEP) and 15 cmH2O (PEEP15) with a
constant rate of 0.67 cmH2O x min(-1). This ramp manoeuvre was performed both
under normal conditions and after induction of an experimental lung oedema.
During the ramp manoeuvre, haemodynamic and pulmonary variables were monitored
almost continuously. RESULTS: During the rise in PEEP, cardiac output declined in
a non-linear way. In the series with normal conditions, best PEEP was always
found at ZEEP. In the series with experimental lung oedema, best PEEP, as defined
by maximum oxygen transport, was found at PEEP1-6, as defined by maximal
compliance, at PEEP7.5 and by maximal arterial oxygen tension (PaO2) at PEEP10
14. CONCLUSIONS: Best PEEP according to oxygen transport is lower than best PEEP
according to compliance and PaO2; the use of PEEP as a ramp might prevent
unnecessarily high levels of PEEP.
PMID- 9757928
TI - Electrical impedance tomography in monitoring experimental lung injury.
AB - OBJECTIVE: To apply electrical impedance tomography (EIT) and the new evaluation
approach (the functional EIT) in monitoring the development of artificial lung
injury. DESIGN: Acute experimental trial. SETTING: Operating room for animal
experimental studies at a university hospital. SUBJECTS: Five pigs (41.3 +/- 4.1
kg, mean body weight +/- SD). INTERVENTIONS: The animals were anaesthetised and
mechanically ventilated. Sixteen electrodes were attached on the thoracic
circumference and used for electrical current injection and surface voltage
measurement. Oleic acid was applied sequentially (total dose 0.05 ml/kg body
weight) into the left pulmonary artery to produce selective unilateral lung
injury. MEASUREMENTS AND RESULTS: The presence of lung injury was documented by
significant changes of PaCO2 (40.1 mmHg vs control 37.1 mmHg), PaO2 (112.3 mmHg
vs 187.5 mmHg), pH (7.35 vs 7.42), mean pulmonary arterial pressure (29.2 mmHg vs
20.8 mmHg) and chest radiography. EIT detected 1) a regional decrease in mean
impedance variation over the affected left lung (-41.4% vs control) and an
increase over the intact right lung (+ 20.4% vs control) indicating reduced
ventilation of the affected, and a compensatory augmented ventilation of the
unaffected lung and 2) a pronounced fall in local baseline electrical impedance
over the injured lung (-20.6% vs control) with a moderate fall over the intact
lung (-10.0% vs control) indicating the development of lung oedema in the injured
lung with a probable atelectasis formation in the contralateral one. CONCLUSION:
The development of the local impairment of pulmonary ventilation and the
formation of lung oedema could be followed by EIT in an experimental model of
lung injury. This technique may become a useful tool for monitoring local
pulmonary ventilation in intensive care patients suffering from pulmonary
disorders associated with regionally reduced ventilation, fluid accumulation
and/or cell membrane changes.
PMID- 9757929
TI - Anticoagulative effect of nitric oxide inhalation in ARDS.
AB - Some studies have suggested that nitric oxide (NO) may cause platelet
dysfunction. We present an ARDS patient who need this treatment, with a transient
alteration of platelet function and a significant prolongation of bleeding time.
PMID- 9757931
TI - Noise sources and levels in the Evgenidion Hospital intensive care unit.
AB - Noise sources and levels were evaluated in a six-bed intensive care unit (ICU) in
Athens, Greece. Ten patients (six males, four females) completed specifically
designed questionnaires, and at the same time nine 8-h sound measuring sessions
took place. A Bruel and Kjaer 2231 sound-meter was used on the decibel-A scale
combined with observation. Human activity, operating equipment and construction
engineering of the hospital building were identified as sources of noise. Noise
levels were elevated [LEQ = 60.3-67.4 dB(A)]. No reliable information was
obtained from the questionnaires. ICU noise levels were higher by 27 dB(A) than
recommended hospitals levels. To counteract noise pollution in ICUs, staff
awareness and sensitivity are needed.
PMID- 9757930
TI - In vitro activity of fleroxacin against multiresistant gram-negative bacilli
isolated from patients with nosocomial infections.
AB - In order to evaluate the in vitro activity of fleroxacin against nosocomial gram
negative organisms, 263 multiresistant gram-negative bacilli (203
Enterobacteriaceae and 60 non-fermenting gram-negative bacilli) were isolated
from adult patients with nosocomial infections. The different patterns of
resistance to eight different antimicrobial agents (ampicillin, carbenicillin,
piperacillin, cephalothin, cefamandole, ceftazidime, gentamicin and amikacin)
were determined by minimum inhibitory concentration (MIC), using the agar
dilution method. The most prevalent multiresistant species isolated were
Klebsiella pneumoniae (28.9%), Escherichia coli (24%) and Pseudomonas aeruginosa
(12.2%). All these bacterial strains showed three to five resistance patterns to
at least three different antibiotics. Resistance to ceftazidime was observed in
at least one of the resistance patterns of isolated bacteria. The activity of
fleroxacin against multiresistant enteric bacteria was excellent; these strains
showed a susceptibility of 79-100%. The susceptibility of P. aeruginosa to
antipseudomonal agents was low; however, the activity of fleroxacin against these
strains was higher than 60% (MIC < or = 2 microg/ ml), broadly comparable with
ciprofloxacin. The resistance to fluoroquinolones detected in this study was no
cause for alarm (3%). Consequently, fleroxacin maintains a remarkable activity
against Enterobacteriaceae and remains highly active against other gram-negative
bacilli. Nevertheless, actions directed at preventing or limiting resistance will
be crucial to maintain the viability of fluoroquinolones as important therapeutic
agents.
PMID- 9757933
TI - A clinician's guide to the use of quality terminology. Working Group on Quality
Improvement of the European Society of Intensive Care Medicine.
PMID- 9757935
TI - Round table conference: acute lung injury, 15th-17th March 1997 Brussels,
Belgium.
PMID- 9757932
TI - Enteral nutrition in intensive care patients: a practical approach. Working Group
on Nutrition and Metabolism, ESICM. European Society of Intensive Care Medicine.
AB - Severe protein-calorie malnutrition is a major problem in many intensive care
(ICU) patients, due to the increased catabolic state often associated with acute
severe illness and the frequent presence of prior chronic wasting conditions.
Nutritional support is thus an important part of the management of these
patients. Over the years, enteral nutrition (EN) has gained considerable
popularity, due to its favorable effects on the digestive tract and its lower
cost and rate of complications compared to parenteral nutrition. However,
clinicians caring for ICU patients are often faced with contradictory data and
difficult decisions when having to determine the optimal timing and modalities of
EN administration, estimation of patient requirements, and choice of formulas.
The purpose of this paper is to provide practical guidelines on these various
aspects of enteral nutritional support, based on presently available evidence.
PMID- 9757934
TI - A European survey of the use of inhaled nitric oxide in the ICU. Working Group on
Inhaled NO in the ICU of the European Society of Intensive Care Medicine.
PMID- 9757936
TI - Kinetics of procalcitonin in iatrogenic sepsis.
PMID- 9757937
TI - Prolonged high-dose administration of sodium nitroprusside in the intensive care
unit.
PMID- 9757938
TI - Survey of vasopressor usage.
PMID- 9757939
TI - Postpartum brain death as a late fatal sequel of a previous skull base fracture.
PMID- 9757940
TI - Two identical episodes of acute quadriparesia in an intensive care unit patient.
PMID- 9757941
TI - Molecular cloning, expression and characterization of rhesus macaque Fas ligand
cDNA.
AB - The Fas/Fas ligand (FasL) interaction is pivotal in apoptosis-mediated regulation
of the immune system. As such, it has relevance in areas of transplantation, gene
therapy, AIDS, etc., all of which utilize the rhesus macaque as a preclinical
animal model. In order to examine rhesus Fas/FasL, we cloned the rhesus FasL cDNA
and have analyzed the function of the cloned gene. Our findings indicate that the
rhesus FasL is highly homologous to the human but not the mouse (97% for human,
85% for mouse). In addition, soluble rhesus FasL can induce apoptosis, a property
shared with the human soluble protein but not the mouse protein. The deduced
protein sequence is 280 amino acids with a calculated Mr. of 31,646. Transfection
of COS cells with the full-length cDNA yielded a 40 KD protein, which is in
agreement with the size of human FasL. COS cells expressing rhesus FasL induced
apoptosis in rhesus PHA blasts and human Fas+ CEM-6 cells. Thus, the cloned
rhesus macaque FasL is functional and cross-reacts with human Fas. The cloned
functional rhesus FasL cDNA will enable studies of its regulatory role in the
nonhuman primate immune system.
PMID- 9757942
TI - The CLIP-substituted invariant chain efficiently targets an antigenic peptide to
HLA class II pathway in L cells.
AB - The presentation of antigenic peptides by major histocompatibility complex (MHC)
class II to CD4+ T cells is crucial to initiate immune responses. We developed a
new system for delivery of an antigenic peptide to the MHC class II pathway,
using the invariant chain (Ii). We designed a mutated human p33-form Ii, CLIP
substituted Ii, in which streptococcal M12p55-68 (RDLEQAYNELSGEA) was substituted
for CLIP (class II associated invariant chain peptide). We examined the peptide
presenting function of this construct, in comparison with the previously reported
C-terminal fused Ii, in which a cathepsin cleavage site and M12p54-68 was ligated
to the C-terminus of Ii. Mouse L cell transfectants expressing either of these
two mutated Ii along with HLA-DR4 could process and present M12p55-68 to the
peptide specific and DR4-restricted CD4+ T cell clone. CLIP-substituted Ii was
much more efficient in antigen presentation than was the C-terminal fused Ii.
Similar to the wild-type Ii, the CLIP-substituted Ii was associated
intracellularly with DR4 molecules. These results indicate that the peptide
substituted for CLIP of Ii p33 bound to the groove of DR molecules in the same
manner as CLIP and it was preferentially presented to the CD4+ T cell clone in
the absence of HLA-DM molecules. This system may prove useful for immunotherapy
with DNA vaccines or for construction of an antigen presenting cell library with
diverse peptides.
PMID- 9757943
TI - Interleukin 2 receptor regulation and IL-2 function in the human infant.
AB - IL-2 receptor is expressed at low levels on adult blood lymphocytes, and at lower
levels on cord blood cells. IL-2 receptor alpha and beta chain expression
increases gradually from 0-18 months of age. The level of soluble CD25 (IL-2
receptor alpha chain) has been reported to be elevated in cord blood.
Quantitative RT-PCR showed that adult cells express 10 times as much CD25 mRNA as
cord cells. Cord plasma showed only a marginal ability to strip CD25 from the
membrane. To assess the functional consequences of low IL-2 receptor expression,
cord and adult cells were activated in vitro. The response was stimulus
dependent, but cord cells upregulated CD25 readily. Cord and adult cells
proliferated in an IL-2-dependent assay to a similar extent. Infants suffering
acute infection showed marginally higher levels of membrane CD25 expression than
infants without overt infection. Thus neonatal and infant lymphocytes express
lower levels of IL-2 receptors than adult cells, reflecting lower mRNA
concentrations at least for CD25; they are able to up-regulate receptors in
response to in vitro stimulation and are able to respond in vitro to IL-2
dependent stimulation; however in vivo there may be a dampening down of the IL-2
system in infancy.
PMID- 9757944
TI - Generation of stable monocyte-derived dendritic cells in the presence of high
concentrations of homologous or autologous serum: influence of extra-cellular pH.
AB - Recent studies have highlighted the high degree of differentiation of monocytes.
Indeed, dendritic cells (DC) can be generated from monocytes, in the presence of
appropriate cytokines. However, human serum is usually avoid in such cultures.
Here, we report that human serum does not inhibit generation of mature DC from
blood monocytes, but rather that extra-cellular pH may play an important role in
the regulation of monocyte differentiation. Indeed, monocytes cultured at pH 7.4
in the presence of high concentrations of human serum developed efficiently into
mature DC, as opposed with monocytes cultured at pH 7. These pH 7.4 cultured DC
presented features characteristic of mature DC, at the phenotypical, functional
and morphological levels. In addition, these DC were stable, with respect to
their sustained expression of CD83 and CD86, upon withdrawal of cytokines.
Finally, when autologous plasma was used instead of homologous serum,
differentiation of monocytes into mature DC was efficient, as well. Thus,
altogether, our data show the importance of extra-cellular pH on differentiation
of monocyte-derived DC in the presence of human serum, which should be maintained
at plasma levels.
PMID- 9757945
TI - T cell responses to 53-kDa outer membrane protein of Porphyromonas gingivalis in
humans with early-onset periodontitis.
AB - Patients with early-onset periodontitis (EOP) are susceptible to infection with
periodontopathic bacteria, such as Porphyromonas gingivalis. Ag53, 53-kDa outer
membrane protein of P. gingivalis, evokes strong humoral immune responses in EOP
patients. In a first step to clarify how host immune cells recognize Ag53, we
established Ag53-specific short-term T cell lines from 22 subjects including 6
EOP patients and 16 healthy donors, using overlapping peptides based on Ag53
amino acid sequences. All T cell lines from active EOP patients recognized a
common region (p141-181, especially p141-161) on Ag53, while those from healthy
donors showed heterogeneous specificity. p141-181 was not recognized by T cell
lines established from EOP patients following therapy. A monoclonal antibody to
HLA-DRB 1 inhibited Ag53-induced proliferation of most of the T cell lines. Our
observations suggest that, although antigen-presenting molecules are common in
EOP patients and in healthy individuals, p141-161 includes a major T cell
epitope(s) on Ag53 for active EOP patients but not for healthy individuals or
inactive EOP patients.
PMID- 9757946
TI - Soluble HLA-I in rheumatic diseases.
AB - OBJECTIVE: To study serum levels of Class I soluble HLA (sHLA-I) in patients with
systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), polymyositis or
dermatomyositis (PM/DM) or scleroderma and to assess the possible influence of
ethnic factors on concentration in each disease group. METHODS: Solid-phase
enzyme linked immunoassay was used to measure sHLA-I in the serum of 385 patients
with varied ethnic backgrounds (American-Caucasians, African-Americans, Georgian
Caucasians) with rheumatic diseases. Studies on patients were compared to similar
measurements of 189 healthy individuals. RESULTS: Mean sHLA-I levels were
significantly higher in patients with SLE than those observed in healthy
individuals or other rheumatic diseases. Highest concentrations were present in
Georgian-Caucasian patients with SLE. American-Caucasian patients with RA or
scleroderma had higher sHLA-I levels than normal Caucasian individuals. The
majority of patients with PM/DM in all ethnic subgroups were low secretors of
sHLA-I. CONCLUSION: Mechanisms underlying the secretion of sHLA-I appear to
differ among the rheumatic diseases studied and various ethnic groups. These
genetic differences in sHLA-I secretion could be associated with ethnic and
pathophysiologic differences among these rheumatic diseases.
PMID- 9757947
TI - Impact of the MHC-encoded HLA-DMA, DMB, and LMP2 gene polymorphisms on kidney
graft outcome.
AB - We previously studied the relationship between TAP1 and TAP2 gene polymorphism
and compatibility in kidney graft outcome and reported that the currently
described TAP1 and TAP2 gene polymorphisms did not influence the incidence of
acute rejection episodes. In this study, we report on the effect of polymorphism
and matching of HLA-DMA, -DMB, and LMP2 genes on kidney graft outcome. This study
was performed on 102 selected kidney recipients who experienced two or more acute
rejection episodes (rejection group) during follow up and who were compared to a
group of 150 patients who never had rejection (non rejection group). Although a
significant effect of HLA-DR matching was observed between these two groups, our
data suggest that matching for all the new genes located in the HLA class II
region (TAP1, TAP2, LMP2, HLA-DMA and -DMB) does not influence the kidney graft
outcome. However, a significant increase (pc < 0.05) of DMA*0102 allele was
observed in the recipients of the rejection group as compared to those of the non
rejection group. This effect was not due to a linkage disequilibrium between DMA
and HLA-DR loci and suggests that this specific HLA-DMA allele could play a role
in the indirect pathway of class II presentation of donor antigens.
PMID- 9757949
TI - A new categorization of HLA DR alleles on a functional basis.
AB - In this analysis, we introduce a new categorization of HLA DR alleles which are
important members of HLA class II genes encoding cell surface glycoproteins that
function to present antigenic peptides to T cells. We have grouped all HLA DR
molecules into seven different functional categories on the basis of their
ability to bind and present antigenic peptides to T cells and their association
with susceptibility or resistance to disease. This novel categorization of DR
alleles on the basis of function allows for the prediction of seven similar
subregion structures (supertypes or supermotifs) within pocket 4 of HLA DR
peptide binding groove as the molecular basis for grouping these alleles. The
physicochemical characteristics of HLA DR supertype residues, charge in
particular, may influence the selectivity for binding peptide, dominate
promiscuous T-cell recognition of antigenic peptides, and affect HLA DR disease
associations. To rationalize the functional categories of DR alleles, we have
further combined the seven DR supertype patterns into three groups based on the
charges of residues within the supertypes. Grouping HLA DR alleles into
functional categories may assist in understanding the mechanistic basis of
autoimmunity, resolving current paradoxes in HLA disease associations, and
developing new immunotherapy strategies.
PMID- 9757950
TI - Nomenclature for factors of the HLA system, update April 1998. WHO Nomenclature
Committee for Factors of the HLA System.
PMID- 9757948
TI - Characterization and distribution of Mhc-DPB1 alleles in chimpanzee and rhesus
macaque populations.
AB - Allelic diversity at the nonhuman primate Mhc-DPB1 locus was studied by
determining exon 2 nucleotide sequences. This resulted in the detection of 17
chimpanzee (Pan troglodytes), 2 orangutan (Pongo pygmaeus) and 16 rhesus macaque
(Macaca mulatta) alleles. These were compiled with primate Mhc-DPB1 nucleotide
sequences that were published previously. Based upon the results, a sequence
specific oligotyping method was developed allowing us to investigate the
distribution of Mhc-DPB1 alleles in distinct chimpanzee and rhesus macaque
colonies. Like found in humans, chimpanzee and rhesus macaque populations
originating from different geographic backgrounds appear to be characterized by
the presence of a few dominant Mhc-DPB1 alleles.
PMID- 9757951
TI - Nomenclature for factors of the HLA system, update May/June 1998. WHO
Nomenclature Committee for Factors of the HLA System.
PMID- 9757952
TI - Endometrial carcinoma after endometrial ablation: high-risk factors predicting
its occurrence.
AB - Our purpose was to review reported cases of endometrial carcinoma after
endometrial ablation and to evaluate high-risk factors predicting its occurrence.
We present guidelines for the treatment of abnormal uterine bleeding unresponsive
to medical therapy in this high-risk group of patients. Eight detailed reports on
endometrial carcinoma after endometrial ablation were reviewed. The indications,
methods of treatment, follow-up, and associated high-risk factors for endometrial
carcinoma were analyzed. A focused list of high-risk factors for endometrial
carcinoma was developed on the basis of the data collected. Guidelines were
established to enable surgeons to minimize the risks of subsequent uterine cancer
in women with abnormal uterine bleeding that is unresponsive to medical therapy
(ie, candidates for ablation). Women who had endometrial carcinoma develop after
ablation had predictive high-risk factors for subsequent neoplasia, and all
eventually underwent a hysterectomy. Women with abnormal uterine bleeding and
high-risk factors for endometrial carcinoma who did not respond to medical
treatment may safely undergo endometrial ablation but must have a preablation
biopsy indicating normal endometrium. Persistent hyperplasia unresponsive to
hormonal therapy should influence the selection of a hysterectomy. Careful
screening of patients before undergoing endometrial destructive procedures is
prescient because minimally invasive, nonhysteroscopic ablative techniques are
now emerging.
PMID- 9757953
TI - Routine maternal platelet count: an assessment of a technologically driven
screening practice.
AB - Because automated blood cell counters are now widely used in many clinical
settings, an assessment of hemoglobin concentration or hematocrit is invariably
accompanied by a platelet count. Thus many asymptomatic pregnant women are being
screened for thrombocytopenia. The objective of a good screening program is to
reduce morbidity and mortality and thereby improve the quality of life; criteria
for the evaluation of proposed or ongoing screening programs are well
established. However, the screening of pregnant women for thrombocytopenia seems
to have been both technologically mandated and passively accepted. Therefore we
systematically evaluated the current de facto screening of asymptomatic pregnant
patients for thrombocytopenia in the context of well-explained, desirable
characteristics for a successful screening program. We conclude that screening
for thrombocytopenia in pregnancy fails to meet established criteria, may
actually be harmful (by placing unaffected fetuses of thrombocytopenic women, and
the women themselves, at risk from invasive procedures), and should therefore be
discontinued.
PMID- 9757954
TI - Oral contraceptive discontinuation: a prospective evaluation of frequency and
reasons.
AB - OBJECTIVES: Our purpose was to define the frequency and reasons for oral
contraceptive discontinuation and subsequent contraceptive behavior. STUDY
DESIGN: A nationwide prospective study of 1657 women initiating or switching to
the use of a new contraceptive from private practices, clinics, and a health
maintenance organization was performed. RESULTS: Six months after a new oral
contraceptive prescription, 68% of new starts and 84% of switchers still used
oral contraceptives. Of women who discontinued, 46% did so because of side
effects, whereas 23% had no continuing need. More than four fifths of women who
discontinued oral contraceptives but remained at risk of unintended pregnancy
either failed to adopt another method or adopted a less effective method. Fifteen
percent of women who discontinued oral contraceptives resumed their use within
the 7-month follow-up period. CONCLUSIONS: Counseling should emphasize the
possibility of side effects, stressing the fact that most will be transient, and
the need to identify a backup method. Follow-up visits should be scheduled for 1
to 2 months after a prescription is written.
PMID- 9757955
TI - Compliance with depot medroxyprogesterone acetate: a randomized, controlled trial
of intensive reminders.
AB - We enrolled women in a prospective, randomized study to determine whether an
intensive reminder system would improve compliance in women receiving depot
medroxyprogesterone injections. Women selecting this treatment were assigned to a
group that received both mail and telephone reminders or to a second group that
received only a scheduled appointment at the time of the previous injection. The
rate of continuation and the rate of on-time injections did not differ between
groups. Women who had prolonged bleeding were more likely to discontinue depot
medroxyprogesterone injections.
PMID- 9757956
TI - Osteitis pubis after Marshall-Marchetti-Krantz urethropexy: a pubic
osteomyelitis.
AB - OBJECTIVE: Our purpose was to review cases of osteitis pubis encountered at our
institution after Marshall-Marchetti-Krantz retropubic urethropexy. STUDY DESIGN:
The charts of patients diagnosed with osteitis pubis subsequent to Marshall
Marchetti-Krantz retropubic urethropexy from 1980 to 1994 were reviewed. RESULTS:
Fifteen cases of osteitis pubis were diagnosed after 2030 Marshall-Marchetti
Krantz procedures (0.74%). Onset of symptoms related to osteitis pubis began a
mean of 69.8 days postoperatively (range 10 to 459 days). Although initial plain
films of the symphysis pubis were normal in 7 (54%), radiographic abnormality was
eventually demonstrated in all a mean of 25.7 weeks after surgery (range 4 to 78
weeks). A variety of conservative treatments resulted in symptomatic relief in
47%. Seven of the remaining patients underwent operative therapy with partial or
complete relief noted in all. Subsequent bone cultures were positive in 5 (71%).
At follow-up a mean of 58 months after the Marshall-Marchetti-Krantz procedure
complete resolution of symptoms was noted in 33% and continued pain or ambulatory
difficulty in the remainder. There was no relationship between postoperative
urinary tract infections, postoperative complications, presenting sign of fever,
elevated leukocyte count or sedimentation rate, and subsequent operative
intervention (P > .05). CONCLUSIONS: Osteitis pubis after urogynecologic surgery
is an uncommon event requiring aggressive surgical and antibiotic therapy. When
bone cultures are performed, a microbial cause may be demonstrated in as many as
71% of patients.
PMID- 9757958
TI - Further evidence that the WT1 gene does not have a role in the development of the
derivatives of the mullerian duct.
AB - OBJECTIVE: Several lines of evidence suggest that expression of the WT1
transcription factor gene is necessary for normal development of the renal and
male reproductive systems. Female patients with severe reproductive tract
developmental defects were examined for WT1 gene mutations. STUDY DESIGN: The WT1
gene was analyzed in 25 patients with congenital absence of the uterus and vagina
for mutations. Genomic deoxyribonucleic acid prepared from blood leukocytes was
subjected to Southern blot analysis and denaturing gradient gel electrophoresis.
RESULTS: Common WT1 gene deoxyribonucleic acid sequence polymorphisms were found
in both normal control subjects and patients with congenital absence of the
uterus and vagina. No deoxyribonucleic sequence differences or mutations likely
to cause congenital absence of the uterus and vagina were detected in the
patients. CONCLUSIONS: The absence of WT1 gene mutations in patients with
congenital absence of the uterus and vagina supports the hypothesis that WT1
expression is required only for later urogenital development, after the
mesonephric and paramesonephric ducts have already formed.
PMID- 9757957
TI - Telomere shortening in uterine leiomyomas.
AB - OBJECTIVE: To gain a better understanding of proliferation control mechanisms in
a common benign tumor, we investigated the mean telomere length and the clonality
of uterine leiomyomas. STUDY DESIGN: Deoxyribonucleic acid from uterine
leiomyomas and from the adjacent normal myometrium of 51 patients (total number
of uterine leiomyomas 107; 28 patients with single leiomyoma, 23 patients with
multiple leiomyomas ranging from 2 to 8 myoma nodules per case) was hybridized to
a telomeric oligonucleotide probe by Southern blot and chemiluminescent
detection. The mean telomere length was evaluated by densitometry. Clonality was
assessed with use of the phosphoglycerokinase gene polymorphism. RESULTS: The
mean telomere length was significantly shorter in uterine leiomyomas (median 7950
bp, interquartile range 7261 to 8372 bp) than in normal myometrium (median 9688
bp, interquartile range 8528 to 10535 bp) (P < .001). There was no correlation
between tumor size and telomere attrition. Multiple uterine leiomyomas were found
to have an independent clonal origin. CONCLUSIONS: Telomere attrition in uterine
leiomyomas reflects enhanced proliferation activity in the course of tumor
evolution. The basic telomere lengths differ in the myocytes from which the
uterine leiomyomas originate, probably explaining the lack of correlation between
telomere attrition and tumor size.
PMID- 9757959
TI - Methotrexate effects on trophoblast and the corpus luteum in early pregnancy.
AB - OBJECTIVE: Our purpose was to determine whether methotrexate affects the
trophoblast or corpus luteum when administered for abortion. STUDY DESIGN: A
randomized controlled trial was performed in women requesting an abortion up to
49 days' gestation. Twenty patients were treated with intramuscular methotrexate
50 mg/m2 (10 women) or 60 mg/m2 (10 women). Serum beta-human chorionic
gonadotropin, progesterone, and 17-hydroxyprogesterone levels were determined at
baseline and then serially after methotrexate administration for the first 24
hours, then every 24 hours for 7 days. On the seventh day misoprostol 800 microg
was administered vaginally. RESULTS: Serum beta-human chorionic gonadotropin
increased at a lower rate than occurs in normal pregnancy. Progesterone levels
averaged 56.9 +/- 19.8 nmol/L at baseline and 45.5 +/- 20.5 nmol/L (P = .01) 1
week after methotrexate. Progesterone decreased in 16 women over the 7 days and
increased in the other 4; these latter women all aborted after a single dose of
misoprostol. Levels of 17-hydroxyprogesterone plateaued during the first day
after methotrexate administration; both progesterone and 17-hydroxyprogesterone
declined simultaneously between the third and fourth day after methotrexate.
CONCLUSIONS: Methotrexate most likely primarily affects trophoblast production of
human chorionic gonadotropin, as evidenced by a blunting of the expected increase
in serum beta-human chorionic gonadotropin resulting in less support for the
production of progesterone by the corpus luteum. However, changes in progesterone
levels after methotrexate administration were inconsistent and are unlikely to
represent the ultimate effect of methotrexate in abortion. The less-than-normal
increase in serum beta-human chorionic gonadotropin levels after methotrexate
administration is most likely a result of disruption of cytotrophoblast
syncytialization. This disruption may be the true effect of methotrexate in
destabilizing the implantation site of an early pregnancy.
PMID- 9757961
TI - Oxytocin receptor and its messenger ribonucleic acid in human leiomyoma and
myometrium.
AB - OBJECTIVE: The study determined the expression of oxytocin receptor and its gene
in human uterine leiomyoma compared with the adjacent myometrium. STUDY DESIGN:
Paired samples of leiomyoma and the adjacent myometrium from 20 women through the
menstrual cycle, menopause, and various hormone treatments were studied. Oxytocin
receptor was immunohistochemically localized with use of the specific antibody
(2F8) to human oxytocin receptor. Oxytocin receptor protein was determined by
Western blotting, whereas reverse transcription-polymerase chain reaction was
used for oxytocin receptor messenger ribonucleic acid expression. RESULTS:
Immunohistochemistry showed positive staining in all tissues examined, relatively
more intense in the myometrium than in the adjacent leiomyoma, and in tissues
from the preovulatory than the postovulatory phase. Western blotting showed a
single 70-kd band corresponding to the oxytocin receptor. The relative abundance
of oxytocin receptor in both leiomyoma and myometrium was significantly higher
during the preovulatory (n = 5) than the postovulatory (n = 5) phase (P = .034
and .05). In women receiving gonadotropin-releasing hormone agonist (n = 1) or
oral contraceptives (n = 1), after the menopause (n = 2), and with irregular
vaginal bleeding (n = 1), oxytocin receptor levels in leiomyoma and myometrium
were unchanged but were reduced in anovulatory cycles (amenorrhea, n = 2).
Reverse transcription-polymerase chain reaction showed messenger ribonucleic acid
for oxytocin receptor as a 391-bp band in all leiomyomas and myometrium examined.
CONCLUSIONS: Leiomyoma and myometrium express the gene and protein for oxytocin
receptor, which is probably partially regulated by ovarian sex steroids during
the menstrual cycle.
PMID- 9757962
TI - Genetic differentiation of complete hydatidiform moles coexisting with normal
fetuses by short tandem repeat-derived deoxyribonucleic acid polymorphism
analysis.
AB - OBJECTIVE: We applied deoxyribonucleic acid polymorphism analysis on the basis of
differences in the number of short tandem repeat sequences to genetically
differentiate dizygotic twins with complete hydatidiform moles and normal fetuses
from partial moles presenting a similar appearance. STUDY DESIGN: Six pregnant
women exhibiting apparent moles and coexisting fetuses were the subjects of this
study. Eight polymorphic loci including short tandem repeat sequences were
amplified by polymerase chain reaction from deoxyribonucleic acid of peripheral
leukocytes of parents, umbilical cord, grossly normal placenta-villi, and molar
tissue. The segregation of alleles among samples were determined by comparing
band patterns on polyacrylamide gels. RESULTS: In all 6 cases amplifications of
polymorphic loci provided sufficient information to determine the parental
origin. At informative loci the alleles of cord and placenta-villi were
transmitted from both patients and husbands whereas molar tissue had only
paternal alleles. These allele segregations indicated 2 different genetic
origins, namely, normal parental for a fetus and androgenetic for molar tissue,
and thus the diagnosis of dizygotic twins with a complete hydatidiform mole and a
normal fetus was made. Additionally, the molar component was defined as a
heterozygous mole in 2 cases. CONCLUSION: Short tandem repeat-derived
deoxyribonucleic acid polymorphism analysis was demonstrated to be a useful and
precise procedure for the differential diagnosis of a complete hydatidiform
coexisting with a normal fetus and the determination of its zygosity as well.
PMID- 9757960
TI - The sequential effects of estrogen administration and hypertension on cardiac
function in ewes.
AB - OBJECTIVE: Our objective was to study the effect of estrogen administration and
moderate hypertension on left ventricular size, pump function, and contractility
in chronically instrumented ewes. STUDY DESIGN: Ewes were either given 0.06 mg/kg
17beta-estradiol intramuscularly (n = 8) or were made hypertensive (n = 6) by
inflation of an occluder around the aorta and were studied weekly. After 3 weeks
each ewe received the opposite treatment. RESULTS: Estrogen administration caused
an increase in left ventricular chamber size at a given pressure, fractional
shortening (21.9% +/- 2.9% to 28.5% +/- 3.7%), and stroke volume (1.4 +/- 0.3
mL/kg to 1.6 +/- 0.3 mL/kg). Subsequent hypertension further increased left
ventricular size at a given pressure but decreased fractional shortening (20.0%
+/- 4.4%) and stroke volume (1.3 +/- 0.3 mL/kg). With hypertension first, there
was no left ventricular enlargement, even with subsequent estrogen
administration, and there were no changes in left ventricular pump function. End
systolic pressure and stress-dimension relationships did not change with either
treatment. The end-systolic wall stress-fractional shortening relationship was
likewise unchanged, suggesting that neither treatment changed contractility.
CONCLUSIONS: The left ventricle previously exposed to hypertension does not
remodel when exposed to estrogen, and cardiac pump function decreases when the
estrogen enlarged heart is faced with moderate, subacute hypertension.
PMID- 9757963
TI - International multicenter term PROM study: evaluation of predictors of neonatal
infection in infants born to patients with premature rupture of membranes at
term. Premature Rupture of the Membranes.
AB - OBJECTIVE: Our objective was to determine significant predictors for the
development of neonatal infection in infants born to patients with premature
rupture of membranes at term. STUDY DESIGN: Multivariate analysis was used to
determine the significant predictors of neonatal infection in infants born to
women with premature rupture of the membranes who were enrolled in the Term PROM
Study. In a randomized, controlled trial, the Term PROM Study recently compared
induction of labor with expectant management for premature rupture of membranes
at term. RESULTS: The following variables were identified as independent
predictors of neonatal infection: clinical chorioamnionitis (odds ratio 5.89, P <
.0001), positive maternal group B streptococcal status (vs negative or unknown,
odds ratio 3.08, P < .0001), 7 to 8 vaginal digital examinations (vs 0 to 2, odds
ratio 2.37, P = .04), 24 to < 48 hours from membrane rupture to active labor (vs
< 12 hours, odds ratio 1.97, P = .02), > or = 48 hours from membrane rupture to
active labor (vs < 12 hours, odds ratio 2.25, P = .01), and maternal antibiotics
before delivery (odds ratio 1.63, P = .05). CONCLUSIONS: Among infants born to
patients with premature rupture of membranes at term, clinical chorioamnionitis
and maternal colonization with group B streptococci are the most important
predictors of subsequent neonatal infection.
PMID- 9757964
TI - Treating ectopic pregnancy with the combination of mifepristone and methotrexate:
a phase II nonrandomized study.
AB - OBJECTIVE: Our goal was to compare the use of a combination of methotrexate and
mifepristone with methotrexate alone in the medical management of ectopic
pregnancy. STUDY DESIGN: This was a preliminary nonrandomized phase II study. All
patients with progressing ectopic pregnancy meeting criteria for medical
management were included. Treatment consisted of 50 mg/m2 of methotrexate
injected intramuscularly and 600 mg of mifepristone, administered orally,
compared with a previous group who received only 50 mg/m2 of methotrexate
injected intramuscularly. RESULTS: Of the 30 patients treated with the
combination, there was only 1 failure, whereas medical treatment had failed for
11 of 42 patients treated with methotrexate alone. CONCLUSIONS: The combination
of mifepristone and methotrexate decreased the risk of failure in medical
treatment of ectopic pregnancy.
PMID- 9757965
TI - Interleukin-1beta and interleukin-8 in cervicovaginal fluid during pregnancy.
AB - OBJECTIVE: We investigated the usefulness of cervicovaginal interleukin-1beta and
interleukin-8 levels during pregnancy as markers of preterm and term parturition.
STUDY DESIGN: Cervicovaginal fluids were obtained from 119 pregnant women at 24
to 41 weeks' gestation. Cytokine concentrations were measured by enzyme-linked
immunoassay. RESULTS: Interleukin-1beta and interleukin-8 concentrations in
cervicovaginal fluids obtained from women not in labor increased exponentially as
gestational age increased. Interleukin-1beta and interleukin-8 concentrations
were significantly correlated. These cytokine concentrations were significantly
higher in patients in preterm labor than in patients at preterm not in labor and
were significantly higher in women at term in labor than in women at term not in
labor. These cytokine levels were significantly correlated with the degree of
cervical dilation and tocolytic index. CONCLUSIONS: These findings suggest that
cervicovaginal interleukin-1beta and interleukin-8 contribute to term and preterm
parturition. Measurement of cervicovaginal concentrations of these cytokines may
be clinically useful in patients with threatened premature delivery.
PMID- 9757966
TI - Evaluating rapid diagnostic tests of intra-amniotic infection: Gram stain,
amniotic fluid glucose level, and amniotic fluid to serum glucose level ratio.
AB - OBJECTIVE: The aim of the study was to compare the diagnostic utility of the Gram
stain, the amniotic fluid glucose level, and the ratio of amniotic fluid glucose
level to serum glucose level in detecting intra-amniotic infection. STUDY DESIGN:
We conducted a prospective study of 127 patients with preterm labor and 26
patients with preterm premature rupture of the membranes (153 total). All
patients underwent amniocentesis to diagnose intra-amniotic infection. The
diagnostic criterion for intra-amniotic infection was a positive amniotic fluid
culture result. RESULTS: The Gram stain is 80% sensitive and 91% specific when a
positive is considered the presence of white blood cells or bacteria. Amniotic
fluid glucose level and the ratio of amniotic fluid glucose level to serum
glucose level are significantly lower when amniotic fluid culture results are
positive, but as diagnostic tests they are inferior to the Gram stain. Logistic
regression models that combine predictors yield superior accuracy with respect to
individual tests. The most accurate combination was amniotic fluid glucose level
and Gram stain with white blood cells or bacteria. Although the number of
patients with preterm premature rupture of the membranes was small in this study
(n = 26), analysis of our data suggests that the diagnostic performance levels of
these tests were similar when used in patients with preterm labor and intact
membranes and in patients with premature rupture of the membranes. CONCLUSIONS:
The amniotic fluid glucose level and the ratio of amniotic fluid to serum glucose
level have equivalent diagnostic utility and are inferior to the Gram stain. The
combination of Gram stain with amniotic fluid glucose level is superior to any
individual test.
PMID- 9757967
TI - Declining cesarean delivery rates in California: an effect of managed care?
AB - OBJECTIVES: We hypothesized that movement from traditional indemnity insurance to
managed care in California between 1983 and 1994 would lead to reductions in the
rate of cesarean delivery. STUDY DESIGN: We decomposed the frequency of cesarean
delivery with each primary diagnosis into the product of the diagnosis rate among
all women and the cesarean delivery rate among women with the given diagnosis
(conditional cesarean delivery rate). We used logistic regression to estimate the
diagnosis and conditional cesarean delivery rates. RESULTS: Adjusted and observed
cesarean delivery rates are indistinguishable. Both the diagnosis rates and the
conditional cesarean delivery rates contributed to the increase in the cesarean
delivery rate between 1983 and 1987. The subsequent decline is attributable to
the decline in the repeated cesarean delivery rate. CONCLUSIONS: The increase in
managed care in California played no apparent role in the decline in the cesarean
delivery rate. With the exception of Kaiser health maintenance organizations,
managed care providers and indemnity insurers managed deliveries similarly.
PMID- 9757968
TI - Serum from preeclamptic women induces vascular cell adhesion molecule-1
expression on human endothelial cells in vitro: a possible role of increased
circulating levels of free fatty acids.
AB - OBJECTIVE: The object was to determine whether serum from preeclamptic women
induces expression of vascular cell adhesion molecule-1 on cultured endothelial
cells. STUDY DESIGN: Endothelial cells were incubated with medium containing 20%
serum (volume/volume) either from women with preeclampsia (n = 15) or from women
with normal pregnancies (n = 15) matched for maternal age, gestational age, and
parity. A further matched set of samples (n = 10) was exposed to endothelial
cells that had previously been incubated in the presence or absence of vitamin E
(40 micromol/L final concentration). Free fatty acids were determined in each
sample. A mixture of free fatty acids (linoleic, oleic, and palmitic acids,
1:1:1) was added to serum from control subjects in increasing concentrations (70
280 micromol/L final concentration) to emulate preeclamptic serum and the
preparation was exposed to endothelial cells. In each experiment vascular cell
adhesion molecule-1 expression was determined after 16 hours of exposure by an
enzyme-linked immunosorbent assay technique performed on the cell monolayer.
RESULTS: Preeclamptic serum had higher levels of free fatty acids than did that
of control subjects (0.71 mmol/L, 95% confidence level 0.5-0.93, vs 0.36 mmol/L,
95% confidence level 0.28-0.43). There was a statistically significant increase
in vascular cell adhesion molecule-1 expression on the endothelial cells exposed
to preeclamptic serum compared with those exposed to control serum (optical
density 0.17 vs 0.11). Vitamin E reduced the vascular cell adhesion molecule-1
expression of endothelial cells exposed both to preeclamptic and to control serum
samples in a nonspecific manner. Addition of free fatty acids to normal pregnancy
serum to mimic the effect of preeclampsia resulted in increased expression of
vascular cell adhesion molecule-1 on the cells. CONCLUSION: Preeclamptic serum
induces vascular cell adhesion molecule-1 expression on human endothelial cells
in vitro, an effect also produced by fatty acids. The elevated level of free
fatty acids in women with preeclampsia may contribute to increased vascular cell
adhesion molecule expression in vivo.
PMID- 9757970
TI - Group B streptococci during pregnancy: a comparison of two screening and
treatment protocols.
AB - OBJECTIVE: The objective was to evaluate whether the rate of neonatal group B
streptococcal infection could be reduced by screening for group B streptococci
during the third trimester of pregnancy. STUDY DESIGN: Two periods in which
different screening and treatment protocols were applied were compared. In period
A all mothers showing high-risk factors were given peripartal antibiotic
coverage. In period B vaginal and rectal smears were routinely obtained in
gestational week 34 and cultured for group B streptococci. If culture results
were positive, the woman received peripartal antibiotics. The incidence of group
B streptococcal infections and the number of peripartal antibiotic doses were
established by comparing 3700 neonates (3623 mothers) in period A with 3648
neonates (3569 mothers) in period B. RESULTS: In period A, 20 group B
streptococcal infections were recorded. Of these, 5 were severe to life
threatening. In period B, 4 group B streptococcal infections were observed. Two
were severe and occurred in neonates born before the mothers could be screened.
Another 2 were mild and occurred in neonates whose mothers had negative screening
test results. The reduction was significant by the chi2 test (chi2 = 9.19, Yates'
corrected P = .0024). The rates of peripartal antibiotic treatment were 11.9% in
period A and 14.5% in period B. CONCLUSION: Although no neonate died of group B
streptococcal sepsis in either of the 2 periods, the protocol used in period B
clearly reduced the incidence of group B streptococcal infection. The number of
peripartal antibiotic doses required was not much higher than in period A.
Screening for group B streptococci in week 34 seems to be a valuable contribution
to further improvement of neonatal outcome.
PMID- 9757971
TI - How small is too small in a twin pregnancy?
AB - OBJECTIVE: The objective was to determine whether small twins had a survival
advantage with respect to small singletons after controlling for other factors
associated with adverse perinatal outcome. STUDY DESIGN: A hospital-based cohort
study included all births between 1980 and 1995 of babies born between 24 and 43
weeks' gestation. Logistic regression was used to estimate the perinatal
mortality risks for monochorionic and dichorionic twins with growth restriction
after adjusting for gestational age, maternal age, parity, method of delivery,
and the presence or absence of congenital malformations. RESULTS: The study
sample included 1062 dichorionic twins, 354 monochorionic twins, and 59,873
singletons. Small monochorionic and dichorionic twins showed a similar overall
risk of perinatal mortality (odds ratio 1.40, confidence interval 0.86 to 2.25).
However, monochorionic twins with birth weights <10th percentile faced an
increased risk of perinatal death compared with singletons (odds ratio 2.45,
confidence interval 1.20 to 5.02). Dichorionic twins had no such increased risk
(odds ratio 0.91, confidence interval 0.45 to 1.84). CONCLUSIONS: Twins with
growth restriction are not protected against perinatal loss, even after adjusting
for congenital malformations. In fact, monochorionic twins are more than twice as
likely to die in the perinatal period as are their singleton counterparts.
PMID- 9757969
TI - The influence of obstetric no-fault compensation on obstetricians' practice
patterns.
AB - OBJECTIVES: The objectives were to determine level of satisfaction among
obstetricians with the no-fault insurance programs in Florida and Virginia and to
study any reported practice patterns attributable to implementation of no-fault
compensation. STUDY DESIGN: Structured surveys were conducted with 119
obstetricians in Florida and Virginia. RESULTS: More than 90% of obstetricians
were enrolled in no-fault insurance programs, but only 13% reported having had a
patient compensated by a no-fault program. Only 14% knew of a colleague with a
patient who had been compensated. Despite no-fault compensation, threat of
lawsuits was a factor in 39% of cases of physicians who quit practicing
obstetrics. The no-fault programs did not cause obstetricians to report increases
in their obstetric caseloads or in their fraction of patients at high risk.
Overall, obstetricians were far more satisfied with the no-fault system than with
the tort system. Still, more than half of the respondents expressed
dissatisfaction with premiums assessed by no-fault insurance. CONCLUSION:
Obstetricians who knew about the no-fault programs were generally satisfied with
their performance. However, the no-fault programs have not built a constituency
with physicians, and the programs are relatively small in their scope of
coverage. No-fault compensation thus has had minor impact on reported obstetric
practice. To be effective in improving patient access, no-fault compensation must
be broader in scope.
PMID- 9757972
TI - Limited usefulness of fetal weight in predicting neonatal brachial plexus injury.
AB - OBJECTIVE: The objectives were to determine the neonatal morbidity rate from
vaginal birth and examine fetal weight-based injury-prevention strategies. STUDY
DESIGN: Selected neonatal morbidities were categorized by birth weight for all
vertex vaginal deliveries occurring during a 12-year period. Sensitivity,
specificity, and predictive values for brachial palsy were calculated at
increasing birth weight cutoff levels. A policy of cesarean delivery for
macrosomic infants was evaluated. RESULTS: There were 80 cases of brachial palsy
among 63,761 infants (0.13%). In mothers without diabetes, rates in the 4500- to
4999-g and >5000-g groups were 3.0% and 6.7%, respectively. A threshold of 3700 g
had a sensitivity of 71% and a specificity of 86%; the positive predictive value
was 0.56%. To prevent a single case of permanent injury, 155 to 588 cesarean
deliveries are required at the currently recommended cutoff weight of 4500 g.
CONCLUSIONS: The rates of lasting morbidity do not justify routine cesarean
delivery for infants without diabetic complications weighing <5000 g.
PMID- 9757973
TI - Persistent abnormalities in plasma volume and renal hemodynamics in patients with
a history of preeclampsia.
AB - OBJECTIVE: The objective was to test the hypothesis that women with a recent
history of preeclampsia have abnormalities in renal hemodynamics and volume
status. STUDY DESIGN: We studied a group of 26 primiparous women with history of
preeclampsia and a group of 12 parous women with a history of uneventful
pregnancies (control group). At least 4 months post partum we compared the
following variables between these groups: effective renal plasma flow, glomerular
filtration rate, plasma volume, plasma concentration of active renin, plasma
concentration of angiotensin II, plasma concentration of aldosterone, and plasma
concentration of atrial natriuretic peptide. RESULTS: Both plasma volume and
plasma concentration of atrial natriuretic peptide were lower in the formerly
preeclamptic group. Compared with the control subjects, the formerly preeclamptic
group also had a lower effective renal plasma flow, a higher filtration fraction,
and a higher renal vascular resistance. Intergroup differences in plasma
concentration of active renin, plasma concentration of angiotensin II and plasma
concentration of aldosterone were small and inconsistent. CONCLUSIONS: Women with
history of preeclampsia are relatively hypovolemic and tend to have lower
effective renal plasma flow and higher renal vascular resistance and filtration
fraction than do control subjects. These findings support the hypothesis that
otherwise healthy women with a history of preeclampsia show abnormalities in
their volume status and renal hemodynamics, irrespective of their blood pressure.
PMID- 9757974
TI - Fetal fibronectin as a marker to discriminate between ectopic and intrauterine
pregnancies.
AB - OBJECTIVE: Our purpose was to determine the accuracy of fetal fibronectin values
for diagnosing ectopic pregnancies. STUDY DESIGN: We obtained vaginal swabs from
women with pregnancies of < or = 12 weeks' gestation to perform enzyme-linked
immunosorbent assays for fetal fibronectin. Fetal fibronectin values were
compared among groups categorized on the basis of clinical and laboratory
criteria into (1) ectopic pregnancies, (2) threatened abortions, (3)
incomplete/complete abortions, and (4) uncomplicated intrauterine pregnancies.
RESULTS: Mean fetal fibronectin values ranged from 0.08 microg/mL in women with
ectopic pregnancies to 0.33 microg/mL in women with threatened abortions.
Comparing these two diagnostic categories, a negative fetal fibronectin test (at
a cutoff level of 0.300 microg/mL) predicted ectopic pregnancy with a sensitivity
of 94%, specificity of 28%, positive predictive value of 62%, and negative
predictive value of 78%. CONCLUSION: Although fetal fibronectin is low in women
with ectopic pregnancies, a negative test is not sufficiently sensitive and
specific to be used clinically for the diagnosis of ectopic pregnancy.
PMID- 9757975
TI - The role of ultrasonography in the detection and management of adnexal masses
during the second and third trimesters of pregnancy.
AB - OBJECTIVE: Our purpose was to determine the effect of routine second-trimester
and third-trimester ultrasonographic examinations on the prevalence of detectable
and operable adnexal disease. STUDY DESIGN: The study group consisted of 7996
pregnant women between 13.0 and 42.8 weeks' gestation. The size and architectural
pattern of any detectable adnexal masses were noted. RESULTS: A total of 328 of
the 7996 (4.1%) women in the study group had 335 ultrasonographically detectable
adnexal masses; 309 of the masses were unilocular or had a single thin septation
and 26 were architecturally complex. Of the ovarian cysts 252 of 309 (81.6%) had
a mean diameter < 3.0 cm; 60% of the 252 patients in this subgroup had serial
ultrasonographic examinations; 43 of the unilocular cysts resolved, and 17 have
persisted for up to 2 years. There is a statistically significant trend toward
decreasing frequency of ovarian cysts with increasing gestational age (chi2 for
linear trend; P < .00001). Eighteen of the 7996 had an exploratory laparotomy (1
operation per 444 deliveries) during pregnancy or in the postpartum period. In
addition, 1 patient had a paratubal cyst excised at the time of postpartum
bilateral tubal ligation. Pathologically confirmed lesions included 8 benign
cystic teratomas, 3 mucinous cyst adenomas, 2 paratubal cysts, 2 corpus lutea, 1
serous cystadenoma, 1 follicular cyst, 1 endometrioma, and 1 ovarian fibroma.
CONCLUSION: Ovarian cysts are found in 4.1% of second-trimester and third
trimester obstetric ultrasonographic examinations. Most ultrasonographically
detectable cysts are < 3.0 cm in diameter and usually resolve. The frequency of
exploratory laparotomy for adnexal disease is not significantly different from
that in reports before the widespread use of obstetric ultrasonography.
PMID- 9757977
TI - The safety of intraoperative autologous blood collection and autotransfusion
during cesarean section.
AB - OBJECTIVE: We evaluated the safety of intraoperative autologous blood collection
and autotransfusion during cesarean section. STUDY DESIGN: A multicenter
historical cohort study identified 139 patients in whom autologous blood
collection autotransfusion during cesarean section was performed. We also
identified 87 control patients who underwent similar surgical procedures at the
same centers without autotransfusion. The outcome variables we compared were
acute respiratory distress syndrome, amniotic fluid embolism, disseminated
intravascular coagulation, need for ventilatory support, infectious morbidity,
and the length of postpartum hospitalization. RESULTS: Demographic and obstetric
characteristics were similar in both groups. The ranges of autotransfused volumes
were 200 to 11,250 mL at Yale, 225 to 1160 mL at Good Samaritan, and 125 to 4750
mL at Hinsdale. No statistically significant differences existed between the two
groups in any of the outcome variables analyzed. No case of acute respiratory
distress syndrome or amniotic fluid embolism was identified in either group.
CONCLUSIONS: Our multicenter experience reveals no demonstrably increased risk of
complications in patients receiving autologous blood collection autotransfusion
during cesarean section.
PMID- 9757976
TI - A "bloodless cesarean section" and perinatal transmission of the human
immunodeficiency virus.
AB - OBJECTIVE: Perinatal transmission of the human immunodeficiency virus is the main
pathway for children to become infected with this virus; however, the relative
contribution and timing of this transmission, whether transplacental or by
exposure through the birth process, have not yet been elucidated. An obvious
question is whether the mode of delivery has an impact on this transmission rate.
However, a routine cesarean section will primarily diminish the duration of
exposure of maternal bodily fluids to the neonate but does not prevent the baby
from being exposed to maternal blood coming from the uterine incision. The
purpose of this study was to determine whether the rate of perinatal transmission
of human immunodeficiency virus could be significantly lowered by delivering the
baby with minimal to no exposure to maternal blood or bodily fluids by the use of
a surgical technique termed a "bloodless cesarean section." STUDY DESIGN: We
performed a prospective cohort study in a group of pregnant women infected with
human immunodeficiency virus and evaluated the rate of transmission of this virus
to the neonate on the basis of the mode of delivery. One group of patients was
delivered by means of a "bloodless cesarean section," in which the baby was
delivered and not exposed to any maternal blood or bodily fluid. The control
group gave birth either by vaginal delivery or by routine cesarean section. All
of the newborns were followed up for a minimum of 15 months or until negative
findings were confirmed. Multiple antenatal, intrapartum, and postdelivery
variables were collected and analyzed. RESULTS: A total of 108 patients were
included in this study and 14 neonates became infected with human
immunodeficiency virus (13%). Three of 53 infants delivered by a bloodless
cesarean section (5.7%) became infected compared with 11 of 55 control patients
(20.0%). This was significant at P = .02 and represented an absolute difference
in percentage between the 2 groups of 14.3%, which corresponds to a 71.5%
relative reduction in transmission risk (z = 2.27, P = .012). Since the use of
zidovudine greatly influences the perinatal transmission rate of human
immunodeficiency virus, the study data were reanalyzed with the exclusion of
patients who used antenatal or intrapartum zidovudine. Two of 32 infants in the
bloodless cesarean section group (6.3%) were infected compared with 9 of 38 in
the control group (23.7%). This was significant at P = .04 and revealed an
absolute difference in percentage of 17.4%, which corresponds to a 73.4% relative
reduction in transmission risk (z = 2.15, P = .016). There was no difference in
the transmission rate between the bloodless cesarean section patients who did not
use zidovudine (2/32, 6.3%) and the patients who did use zidovudine from the
entire study population (3/38, 7.9%). CONCLUSION: In the absence of zidovudine
usage, these data show that 70% to 75% of the perinatal transmission of human
immunodeficiency virus to a newborn occurs from exposure to maternal blood and
bodily fluids at the time of birth. This information is important for patients
unable to take zidovudine or other antiretroviral agents, but more important, it
introduces the concept of other treatment options for the future.
PMID- 9757978
TI - The effects of nitric oxide on the contractility of isolated uterine and aortic
rings from pregnant rats.
AB - OBJECTIVE: The object was to compare the effects of nitric oxide on isolated
uterus and aorta of pregnant rats. STUDY DESIGN: Rings of uterus and thoracic
aorta without endothelium from Sprague-Dawley rats at mid and late gestation were
used for isometric tension recording. The concentration-response curve for
diethylamine/nitric oxide was studied in the presence or absence of oxyhemoglobin
(10(-5) mol/L), or oxyhemoglobin was added after the response to
diethylamine/nitric oxide. RESULTS: Diethylamine/nitric oxide concentration
dependently inhibited uterine contractions, and the effect was attenuated by
previous treatment with oxyhemoglobin at mid gestation (n = 8). The effects were
negligible at late gestation (n = 8). The relaxation of aortic rings by
diethylamine/nitric oxide and its attenuation by previous treatment with
oxyhemoglobin were similar at mid (n = 6) and late (n = 6) gestation. The
sensitivity of aortic rings to diethylamine/nitric oxide is significantly higher
than that of uterine rings. Oxyhemoglobin partly restored inhibited
diethylamine/nitric oxide phenylephrine tension in aortic rings and had no effect
on diethylamine/nitric oxide-inhibited uterine rings. CONCLUSIONS: Uterine smooth
muscle is less sensitive to nitric oxide than is aortic smooth muscle. Nitric
oxide sensitivity of rat uterus but not aorta decreases toward term.
PMID- 9757980
TI - Explicit memory in pregnant women.
AB - OBJECTIVE: The study was conducted to systematically investigate previous
anecdotal reports of memory decline during pregnancy. STUDY DESIGN: We used a
longitudinal design to investigate memory in women throughout pregnancy and in
the postpartum period. Closely matched, nonpregnant women were similarly studied
at equivalent intervals. We also assessed degree of depression and anxiety.
RESULTS: There was a significant time-by-group interaction (P < .01) for both
immediate and delayed recall of paragraph length material. Contrasts showed a
significant decline in memory for the pregnant group from the second to the third
trimester (P < .01). No significant changes in memory were noted for the control
group. The pregnant women scored higher on both depression and anxiety scales;
however, somatic rather than cognitive items accounted for the elevated scores.
Fluctuations in mood and memory did not coincide. CONCLUSION: There is a
pregnancy-related decline in memory, which is limited to the third trimester. The
decline is not attributable to depression, anxiety, sleep deprivation, or other
physical changes associated with pregnancy.
PMID- 9757979
TI - The safety of omeprazole during pregnancy: a multicenter prospective controlled
study.
AB - OBJECTIVES: Our purpose was to determine whether omeprazole use during pregnancy
is associated with an increased risk of malformations, spontaneous abortions,
decreased birth weight, or perinatal complications. STUDY DESIGN: In a
multicenter, prospective controlled study, pregnant women exposed to omeprazole
during gestation were matched with controls exposed to nonteratogens and with
disease-paired controls who used histamine blockers for similar indications. The
primary end point was the incidence of major malformations. RESULTS: One hundred
thirteen pregnant women were exposed to omeprazole during pregnancy. Rates of
major malformations in the omeprazole group (4%) did not differ from controls
exposed to nonteratogens (2%) (P = .68, relative risk = 1.94, 95% confidence
interval 0.36 to 10.36) and disease-paired controls (2.8%). Birth weight,
gestational age at delivery, preterm deliveries, and neonatal complications were
comparable among the three groups. CONCLUSIONS: No association was found between
exposure to omeprazole during the period of organogenesis and increased risk for
major malformations. Exposure throughout pregnancy is not associated with
increased risk of spontaneous abortions, decreased birth weight, or perinatal
complications.
PMID- 9757981
TI - Midtrimester urine human chorionic gonadotropin beta-subunit core fragment levels
and the subsequent development of pre-eclampsia.
AB - OBJECTIVE: Our purpose was to determine whether midtrimester maternal urine human
chorionic gonadotropin beta-subunit core fragment predicts later pre-eclampsia.
STUDY DESIGN: Urine beta-core fragment levels standardized to spot creatinine
concentration and expressed as multiples of the median were prospectively
determined in 347 midtrimester singleton pregnancies undergoing genetic
amniocentesis. All women considered in the analysis were white and nonsmokers.
Obstetric chart review was undertaken after delivery to identify cases in which
pre-eclampsia developed. The risk of pre-eclampsia at different threshold levels
of beta-core fragment of human chorionic gonadotropin was determined. RESULTS:
The median maternal age was 36.0 years, with a median gestational age at urine
collection of 16.0 weeks. The median level of the beta-core fragment of human
chorionic gonadotropin was 1385.5 ng/mg of creatinine in those with pre
eclampsia, whereas that in those without pre-eclampsia was 1061.2 ng/mg. The
difference was significant (Mann-Whitney U test, P = .03). A significant linear
association was found between the beta-core fragment concentration and the risk
of pre-eclampsia (Mantel-Haenszel test of linear association, P = .03). The
relative risk and 95% confidence interval of subsequent pre-eclampsia increased
from 2.07 (1.06 to 4.05) at beta-core fragment levels of human chorionic
gonadotropin > or = 2.0 multiples of the median to 5.17 (1.95 to 13.7) at > or =
4.0 multiples of the median. CONCLUSION: Clinically normal patients with elevated
midtrimester levels of urine beta-core fragment of human chorionic gonadotropin
are at increased risk for the subsequent development of pre-eclampsia. The
clinical value of this urine analyte as a marker for pre-eclampsia needs to be
further investigated.
PMID- 9757982
TI - Outcomes of very low birth weight twins cared for in the National Institute of
Child Health and Human Development Neonatal Research Network's intensive care
units.
AB - OBJECTIVE: The study's aim was to compare outcomes of very low birth weight twins
with those of matched singletons. STUDY DESIGN: With data from the Neonatal
Research Network registry (May 1991 to December 1994), univariable and
multivariable comparisons of very low birth weight twin pairs and singletons were
performed in 2 subgroups: (1) all paired twins and singletons with birth weights
between 401 and 1500 g and (2) all paired twins and singletons born at <28 weeks'
gestation. RESULTS: Twins constituted 19% of infants admitted with very low birth
weight. Mothers of twins were more likely to receive prenatal care, have labor,
have cesarean delivery, and receive antenatal glucocorticoids. Twins were more
likely to have respiratory disease and to receive surfactant. Second-born twins
had more early respiratory disease but similar longer-term outcomes. The risks of
death, chronic lung disease, and grade III or IV intracranial hemorrhage were
similar in twins and singletons. CONCLUSIONS: Although very low birth weight
twins compose a sizable proportion of admissions, in National Institute of Child
Health and Human Development Neonatal Research Network intensive care units,
twins and singletons have similar outcomes.
PMID- 9757983
TI - Evidence for mechanisms of the acute-phase response to endotoxin in late
gestation fetal goats.
AB - OBJECTIVE: The aim of this study was to evaluate the relationship between febrile
response to fetal endotoxin administration and fetal plasma endogenous pyrogen,
tumor necrosis factor-alpha, the possible putative pyrogen mediator prostaglandin
E2, and the endogenous antipyretic arginine vasopressin in late-gestation
pregnant goats. STUDY DESIGN: Changes in fetal core temperature, plasma tumor
necrosis factor-alpha, prostaglandin E2, and arginine vasopressin levels were
measured after administration of Escherichia coli endotoxin (70 microg/kg of
fetal weight) to 10 fetal goats in late gestation. RESULTS: Fetal body
temperature did not rise after endotoxin administration. Fetal plasma tumor
necrosis factor-alpha and arginine vasopressin increased to 87.5 +/- 15.2 pg/mL
and 25.1 +/- 4.8 pg/mL, respectively, after 1 to 2 hours (P < .05). Fetal plasma
prostaglandin E2 levels did not change significantly throughout the study.
CONCLUSION: The absence of a febrile response to endotoxin in late-gestation
fetal goats is accompanied by a deficient responses in prostaglandin generation
in the periphery and increased activity of the antipyrogen arginine vasopressin.
PMID- 9757984
TI - Proton magnetic resonance spectroscopy of fetal lamb brain during hypoxia.
AB - Proton magnetic resonance spectroscopy of fetal lamb brain was performed
simultaneously with repeated measurements of fetal arterial oxygen saturation
during decrease of oxygen supply. Magnetic resonance spectra displayed the same
metabolite peaks as detected in the human fetal brain. Cerebral lactate signals
could be detected during fetal hypoxia.
PMID- 9757985
TI - Placental transfer of ritonavir with zidovudine in the ex vivo placental
perfusion model.
AB - OBJECTIVE: The object was to determine the placental transfer of ritonavir alone
and in combination with zidovudine. STUDY DESIGN: Twelve placental perfusion
studies were performed at trough (1-2 microg/mL) and peak (approximately 20
microg/mL) combinations of ritonavir and zidovudine. Accumulation of ritonavir
was determined. RESULTS: Transfer of ritonavir at trough concentrations was
undetectable (<0.025 microg/mL). The clearance index of ritonavir at peak
concentration was 0.085 +/- 0.05 and was unaffected by zidovudine. The fetal
concentration of ritonavir was 0.0758 +/- 0.22 microg/mL at a maternal
concentration of approximately 20 microg/mL and 25.5 +/- 6.9 microg/mL at a
concentration of 100 microg/mL. There was no tissue accumulation of ritonavir
either alone or with zidovudine. CONCLUSION: The clearance index of ritonavir at
therapeutic levels was extremely low, with little accumulation in the fetal
compartment and no accumulation in placental tissue. Zidovudine does not
significantly affect the transfer or accumulation of ritonavir.
PMID- 9757986
TI - Effects of fetal sex and race on risk of very preterm birth in twins.
AB - OBJECTIVE: Our purpose was to determine whether the risk of twin preterm birth
correlates with the number of male fetuses. STUDY DESIGN: Among 8109 white and
1884 black twin pregnancies in the Missouri Successive Pregnancy Birth/Death Data
Set, 1978 through 1990, risk for preterm birth at various gestational ages was
determined with 0, 1, or 2 male infants. RESULTS: Studied as individuals, white
preterm twins <35 weeks' gestation demonstrated a 9.2% excess of male fetuses (P
< .001). Adjusted for monozygosity, risk for preterm birth <35 weeks' gestation
was 15.7% in white female-female pairs, 17.9% in unlike-sex white fetuses, and
20.2% in white male-male pairs (r = .999, P = .01). The effect was absent in
black pregnancies and was unrelated to birth order, cesarean delivery, parity,
twins' weight differential, year, or season. CONCLUSIONS: In white twin
gestations the observed linear relationship between the number of male fetuses
and the likelihood of preterm birth <35 weeks' gestation suggests a fetal
mechanism for preterm birth <35 weeks' gestation linked to fetal sex. Studies of
mechanisms for preterm birth must stratify by fetal sex and race.
PMID- 9757987
TI - A randomized pilot trial of administration of granulocyte colony-stimulating
factor to women before preterm delivery.
AB - OBJECTIVE: The object was to determine whether administering recombinant human
granulocyte colony-stimulating factor to women before a preterm delivery (< or =
30 weeks' gestation) would improve fetal neutrophil production and neonatal
outcome without adverse maternal effects. STUDY DESIGN: A single dose (25
microg/kg) of recombinant human granulocyte colony-stimulating factor or placebo
was given to 26 women in preterm labor in a randomized, double-blind study.
Neutrophil production was assessed by marrow aspirations of neonates 24 hours
after delivery, blood neutrophil counts were measured in neonates for 1 week, and
Scores for Neonatal Acute Physiologic State were calculated on days 1 and 7 of
life. RESULTS: Of the 26 women enrolled, 16 were delivered of 20 infants within 3
weeks of receiving recombinant human granulocyte colony-stimulating factor. We
found no apparent adverse effect on pregnancy duration or maternal comfort. The
neonates born to mothers treated with recombinant human granulocyte colony
stimulating factor had a significantly greater marrow proliferative pool (P < .05
vs placebo) and a significant improvement in Scores for Neonatal Acute
Physiologic State between days 1 and 7 (P < .02). CONCLUSIONS: Recombinant human
granulocyte colony-stimulating factor administration to women before preterm
delivery appears to have no significant immediate adverse effects on either the
mother or the infant, and it could increase fetal neutrophil production and
improve neonatal outcome.
PMID- 9757988
TI - Maternal diabetes alters extracellular matrix protein levels in rat placentas.
AB - OBJECTIVES: The aim of this study was to determine whether maternal diabetes
affects placental levels of the extracellular matrix components fibronectin,
laminin, and collagen-IV. STUDY DESIGN: Fibronectin, laminin, and collagen-IV
deposition in term (day 20) rat placentas from normal and diabetic pregnancies
was detected by use of Western blot, slot-blot, and immunohistochemical studies.
RESULTS: Increased placental and decreased fetal wet weight were found in
offspring of manifestly diabetic rats compared with offspring of normal
pregnancies. Laminin deposition was reduced whereas fibronectin levels were
increased in placentas from diabetic rats. No diabetes-induced changes of
collagen-IV expression and deposition were found. CONCLUSION: The diabetes
induced alterations of laminin and fibronectin protein levels in the fetal
maternal interface may affect placental development and alter gas exchange and
nutrient transfer to the offspring. This may in turn contribute to the abnormal
fetal development in diabetic pregnancy.
PMID- 9757989
TI - Population differences affect the interpretation of fetal nonstress test results.
AB - OBJECTIVE: The object of the study was to determine whether population
differences exist with respect to outcomes of women with reactive and nonreactive
nonstress test results. STUDY DESIGN: An epidemiologic evaluation was conducted
on 2579 women who underwent nonstress tests in the Fetal Assessment Center of the
Johns Hopkins Hospital within a week of delivery. Risk factors such as
hypertension, diabetes, and postterm pregnancy were used in a logistic regression
model to evaluate the ability of the nonstress test to predict outcomes including
proxies of fetal distress and fetal and neonatal death. The sensitivities,
specificities, and predictive values of the nonstress test for predicting these
outcomes in cohorts of black and white women were also determined. RESULTS: The
nonstress test was consistently more sensitive for black women than for white
women in predicting several perinatal outcomes, but specificity and negative
predictive value were consistently lower for black women. The positive predictive
value for fetal and neonatal death was higher for white women than for black
women. Although the nonreactive nonstress test result seemed to be predictive of
certain perinatal events, the odds ratio for predicting perinatal mortality in
any study population was no greater than when the nonstress test result was
reassuring. CONCLUSIONS: Epidemiologic characteristics affecting test results,
such as disease prevalence and population differences, may lead to clinically
significant differences in outcome prediction when these tests' results are used.
These differences should be considered in the implementation of antepartum fetal
testing programs.
PMID- 9757990
TI - Immunoreactive adrenomedullin in human fetoplacental tissues.
AB - OBJECTIVE: Adrenomedullin is increased in maternal plasma in pregnancy and has
been found in very high concentrations in amniotic fluid and umbilical plasma. To
identify adrenomedullin-producing tissue in pregnancy we measured adrenomedullin
concentration and distribution in fetoplacental tissues. STUDY DESIGN: By use of
a specific radioimmunoassay we determined the concentrations of adrenomedullin
and, by immunohistochemical studies, its localization and distribution in fetal
membranes and placentas collected at elective cesarean section from 11 healthy
pregnant women at term. RESULTS: The content of adrenomedullin in placentas
(117.7 +/- 7.8 pg/mg wet tissue) and fetal membranes (168.7 +/- 2.3 pg/mg wet
tissue) was similar to the adrenomedullin concentration in adrenal medulla (157.3
+/- 4.4 pg/mg wet tissue). Adrenomedullin staining appears to be greater in fetal
membranes than in placentas and was localized in amnion and trophoblast cells. In
term placentas positive staining was detected predominantly in extravillous
trophoblast cells, although a few syncytiotrophoblast cells and endothelial cells
of primary villi stained for adrenomedullin. CONCLUSION: This study provides
evidence that is consistent with fetoplacental tissues as a site of synthesis or
action of adrenomedullin during pregnancy.
PMID- 9757991
TI - Abundant vascular anastomoses in monoamniotic versus diamniotic monochorionic
placentas.
AB - OBJECTIVE: The study's aim was to compare the vascular anatomy of monoamniotic
with uncomplicated diamniotic monochorionic pregnancies. STUDY DESIGN: The
fetoplacental circulations of both twins in 18 monochorionic placentas were
perfused after delivery under optimal physiologic conditions, and anastomoses
were delineated by dye-contrast injection. Six were from pregnancies with
monochorionic monoamniotic twins and 12 from uncomplicated monochorionic
diamniotic twin pregnancies. RESULTS: The cord insertions in monochorionic
monoamniotic placentas were central, with a median intercord distance of 3.2 cm
(range 1.7 to 6.9 cm), whereas in monochorionic diamniotic control placentas the
cord insertions (n = 24) were rarely central (marginal, 13; velamentous, 2) or
eccentric (6), with a mean intercord distance of 9.6 cm (5.2 to 16.7; P < .001).
Cord entanglement was present in 5 of 6 cases of monochorionic monoamniotic
placentas and in none of the monochorionic diamniotic placentas. Monochorionic
monoamniotic placentas had more anastomoses than did monochorionic diamniotic
placentas, both overall (median 13 vs 5 respectively, P < .01) and for each of
the different types (arterioarterial, venovenous, and arteriovenous, P < .01).
CONCLUSIONS: Monoamniotic monochorionic placentas have significantly greater
numbers of both superficial and deep anastomoses than do uncomplicated
monochorionic diamniotic pregnancies. This observation suggests a vascular basis
for the extreme rarity of twin-twin transfusion syndrome in monoamniotic
pregnancies.
PMID- 9757992
TI - The effect of transforming growth factor and interleukin-10 on interleukin-8
release by human amniochorion may regulate histologic chorioamnionitis.
AB - OBJECTIVE: Amniochorion is a source of interleukin-8 during infection and
inflammation. In this study we investigate the role of 2 immunoinhibitory
cytokines, transforming growth factor and interleukin-10, in regulating
interleukin-8 production from human fetal membranes and define their mechanism of
regulation. STUDY DESIGN: Amniochorion was placed in an organ explant system for
72 hours. Tissues were stimulated with lipopolysaccharide (50 ng/mL),
lipopolysaccharide plus transforming growth factor-beta (50/50, 50/100),
transforming growth factor-beta (50 and 100 ng/mL), lipopolysaccharide plus
interleukin-10 (50/50 and 50/100), and interleukin-10 (50 and 100 ng/mL) in
culture. Tissue and media samples were frozen until quantitation of interleukin-8
messenger ribonucleic acid and protein. Quantitation of messenger ribonucleic
acid was performed by quantitative competitive polymerase chain reaction and
protein by enzyme-linked immunoassay, respectively. RESULTS: Lipopolysaccharide
stimulated tissues produced approximately 6 x 10(6) molecules per microliter of
interleukin-8 messenger ribonucleic acid compared with 6 x 10(3) molecules per
microliter in controls. Transforming growth factor-beta alone and
lipopolysaccharide plus transforming growth factor-beta stimulation produced 6 x
10(5) and 6 x 10(4) molecules of interleukin-8 messenger ribonucleic acid per
microliter, respectively. Tissues stimulated with lipopolysaccharide plus 50
ng/mL interleukin-10 produced approximately 600 molecules per microliter of
interleukin-8 messenger ribonucleic acid, whereas no amplifiable messenger
ribonucleic acid was detected in tissues treated with lipopolysaccharide plus 100
ng/mL interleukin-10. Tissues treated with interleukin-10 alone produced 6 x
10(3) molecules of messenger ribonucleic acid, similar to control levels. Enzyme
linked immunosorbent assay data showed similar levels of interleukin-8 peptide
release from lipopolysaccharide and lipopolysaccharide plus transforming growth
factor-beta-treated fetal membranes. A dose-dependent decrease in interleukin-8
peptide release was seen in tissues treated with lipopolysaccharide plus
interleukin-10, whereas stimulation with transforming growth factor or
interleukin-10 alone resulted in interleukin-8 peptide release similar to that of
control levels. CONCLUSION: Transforming growth factor-beta seems to have no
effect on interleukin-8 protein production in the presence of an infectious
agent; however, a drop in messenger ribonucleic acid levels was observed.
Interleukin-10 in the presence of lipopolysaccharide showed down-regulation of
interleukin-8 messenger ribonucleic acid expression and peptide production. These
data suggest that fetal membrane interleukin-8 production can be controlled by
interleukin-10 during an infectious process.
PMID- 9757993
TI - Fetal blood sampling immediately before and within 24 hours of death in
monochorionic twin pregnancies complicated by single intrauterine death.
AB - OBJECTIVE: Our goal was to investigate the mechanisms that play a role in
intrauterine death in monochorionic twins and that contribute to the high
perinatal mortality and morbidity in the survivors. STUDY DESIGN: In 8
monochorionic twin pregnancies complicated by the intrauterine death of a single
twin, we took samples from 5 twin fetuses immediately before death and from 4 of
their cotwins and also from 4 surviving fetuses within 24 hours after death of
the cotwin. RESULTS: Four of the 5 fetuses sampled who subsequently died were
acidemic and 3 were hypoxemic. None of these fetuses or their cotwins were anemic
at that time. All 4 survivors sampled within 24 hours of the death of each cotwin
had low hematocrits. CONCLUSION: Fetal anemia, probably the consequence of acute
blood loss just before the time of death of the cotwin, may play a role in the
high mortality and morbidity found in the surviving twin. It is unlikely that
immediate delivery of the surviving twin after death could affect the outcome.
PMID- 9757994
TI - The detection of diminished ovarian reserve in infertile women.
AB - Women in their mid to late 30s and early 40s with infertility constitute the
largest portion of the total infertility population. These women frequently
undergo multiple testing, and most will require expensive and invasive therapies,
including assisted reproductive technologies, with markedly reduced pregnancy
rates in those older than 40. These women also have a higher incidence of
pregnancy loss even after documentation of fetal cardiac activity by
ultrasonography. Identifying those women who have a very low chance of pregnancy
(and a high chance of pregnancy loss) with their own gametes presents a daily
challenge to the practicing clinician, especially before embarking on expensive
treatments. This article reviews the contemporary investigation of reproductive
aging with basal and provocative tests. Women with markedly diminished ovarian
reserve should be counseled on their low chances of conception with their own
gametes, even with assisted reproductive technologies.
PMID- 9757995
TI - Intravenous nitroglycerin in obstetrics: a new indication.
AB - Intravenous nitroglycerin has been reported to be efficient in various emergency
obstetric situations. We report here the first case of intravenous nitroglycerin
use in a 20-week pregnant woman with abruptio placentae and hypertonia leading to
in utero fetal death and difficult delivery.
PMID- 9757996
TI - Aortic coarctation diagnosed after hypertension in pregnancy.
AB - Coarctation of the aorta is an unusual cause of hypertension in pregnancy because
the disorder in adults is often unrecognized by obstetricians or general
practitioners managing antenatal clinics. We report 3 women with adult
coarctation of the aorta that was diagnosed in the hypertension clinic after
hypertensive pregnancies where the diagnosis had been missed.
PMID- 9757997
TI - Benign schwannoma of the obturator nerve: a case report.
AB - We describe a schwannoma of the obturator nerve in a woman 66 years old. It was
diagnosed only postoperatively because of the aspecificity of the symptoms. The
difficulty of making a correct diagnosis during surgery is discussed, and the
potential serious consequences of total excision of the nerve are described.
PMID- 9757998
TI - Papillary thyroid carcinoma manifesting as thyroid storm of pregnancy: case
report.
AB - A patient with known hyperthyroidism was seen at 25 weeks' gestation with a
rapidly growing neck mass. She was initially in thyroid storm and received
aggressive medical therapy. Two subsequent episodes of thyrotoxicosis occurred
during pregnancy in spite of large doses of propylthiouracil. Post partum the
patient was diagnosed with a locally advanced thyroid malignancy.
PMID- 9757999
TI - Primary hepatoid carcinoma of ovary in pregnancy.
AB - We report a rare case of a 35-year-old woman with primary hepatoid carcinoma of
the ovary during pregnancy associated with abnormal levels of maternal serum
alpha-fetoprotein. This tumor should be considered in the differential diagnosis
of pregnant women with very high levels of maternal serum alpha-fetoprotein
whenever other maternal or fetal sources are excluded.
PMID- 9758001
TI - Hypoxic-ischemic fetal insult resulting from maternal aortic root replacement,
with normal fetal heart rate at term.
AB - A patient with Marfan's syndrome was seen at 29 weeks' gestation with acute
aortic dissection. She underwent aortic root replacement under deep hypothermia
and circulatory arrest. The fetal heart rate was ominous during surgery but
recovered later. Serial ultrasonographic examinations showed progressive fetal
brain atrophy. The patient was delivered at 38 weeks' gestation of a girl
weighing 2305 g, in whom severe spastic tetraplegia, absent psychomotor
development, and therapy-resistant epilepsy developed. This is the first case to
document progressive fetal brain atrophy after cardiac surgery in pregnancy.
PMID- 9758000
TI - Intrahepatic cholangiocarcinoma masquerading as the HELLP syndrome (hemolysis,
elevated liver enzymes, and low platelet count) in pregnancy: case report.
AB - A young woman was seen at 26 weeks' gestation with a clinical profile consistent
with the HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet
count). The patient underwent cesarean delivery and was found to have a massive
tumor involving the liver. After correction of the coagulopathy, a liver biopsy
specimen demonstrated an intrahepatic cholangiocarcinoma. The patient died 3
weeks after diagnosis.
PMID- 9758002
TI - The failed suppression of serum estradiol level by gonadotropin-releasing hormone
agonist in a case of pelvic endometriosis.
AB - We report a case in which gonadotropin-releasing hormone agonist for a patient
with pelvic endometriosis did not suppress the endometrial growth or serum levels
of estradiol or follicle-stimulating hormone but did that of luteinizing hormone,
regardless of the therapeutic dose in blood.
PMID- 9758003
TI - Uterine leiomyoma as a rare cause of acute abdomen and intestinal gangrene.
AB - A rare case of mesenteric vein thrombosis and small intestinal gangrene caused by
a pedunculated fundal uterine fibroid is presented. The causative mechanism and
management are discussed.
PMID- 9758004
TI - Brachial artery rupture complicating a pregnancy with neurofibromatosis: a case
report.
AB - A 30-year-old black woman was first seen at 34 weeks' gestation with pain in the
right arm, which was already afflicted with neurofibroma. She was in hypovolemic
shock on presentation, and after she was resuscitated, a live infant was
delivered. The patient was diagnosed with a pseudoaneurysm of the right brachial
artery with extravasation of blood in the interstitium of the arm. Although there
have been other reported cases of arterial rupture in pregnancies with
neurofibromatosis, the report of brachial artery rupture in this situation is
believed to be the first documented case.
PMID- 9758005
TI - Fetal growth restriction induced by cortisone 40 years ago.
PMID- 9758006
TI - Recurrent spontaneous ovarian hyperstimulation syndrome.
PMID- 9758007
TI - Comments on the quality of citations in journals.
PMID- 9758008
TI - Diurnal rhythms of labor and delivery.
PMID- 9758009
TI - More (and less) on shoulder dystocia.
PMID- 9758010
TI - Is it polycystic ovary syndrome causing the hyperstimulation again?
PMID- 9758011
TI - The social ecology of drug use: a factor analysis of an urban environment.
AB - Drug use is related to the environment in which drug users live. Using 32
economic, housing, crime, and health variables for 1990 census tracts in Houston,
Texas, this study found four identifiable factors: social disorganization,
economic success, threat of violence, and chronic disease. Narcotic offenses
loaded strongly on one and weakly on two of the factors; this variable did not
load on the economic success factor. These results suggest that a textured look
at drug use environments finds them to be multidimensional. Urban dwellers must
deal with the independent effects of social disorganization, economic conditions,
chronic disease, and violence.
PMID- 9758012
TI - Stressful life events and adolescent substance use and depression: conditional
and gender differentiated effects.
AB - Stressful life circumstances have myriad influences on human health and behavior.
Early research focused on the variable distribution of stress and its effects by
socioeconomic status, race, and gender. More recent research indicates that
variation by age is also an important consideration. For example, adolescent
reactions to stressful life events are often inconsistent with adult reactions to
similar life situations and transitions. Moreover, since most studies assess only
a single outcome--usually depression--they risk classification bias since
analyses exclude other potential stress-related outcomes. This paper assesses the
gender distinct effects of stressful life events on two outcomes among
adolescents, substance use and depressive symptoms. The results of a second-order
regression model indicate that life events affect female, but not male,
depressive symptoms, especially when self-esteem is low or mastery is high.
Furthermore, life events affect substance use when peer drug use is high, or when
parental support is low, but this latter effect is limited to female adolescents.
PMID- 9758013
TI - Drug identity change processes, race, and gender. I. Explanations of drug misuse
and a new identity-based model.
AB - The present paper explores race and gender differences in a recent theoretical
model (Anderson, 1994), consisting of several micro- and macrofactors, that helps
explain the identity-related processes of drug misuse. The approach is
qualitative, featuring in-depth interviewing with 45 self-identified drug
addicts. The study uncovered support for the general concepts of the identity
based model across four subgroups: Black females, White females, Black males, and
White males. However, important race and gender differences emerged. Gender and
race-related socialization and stratification explain most of the differences and
suggest reconceptualization of the model. The investigation further demonstrates
the promise of identity-based approaches in extending our knowledge of the
etiology of drug misuse and related intervention policies.
PMID- 9758014
TI - Interaction effects of client and treatment program characteristics on retention:
an exploratory analysis using hierarchical linear models.
AB - This paper applied a hierarchical linear modeling approach to explore the
interaction effects of treatment program and client characteristics on client
retention in treatment for drug users. Program characteristics included services
provision, funding sources, and staff-client gender congruence, and client
characteristics included gender, age at admission, and drug use level prior to
admission. The same model was applied separately to three modalities:
residential, methadone maintenance, and outpatient drug-free programs. Data were
obtained from 59 treatment programs and 3,764 of their clients who had discharge
records. The most noteworthy significant interaction effect detected was
program's funding source and client's gender on treatment retention in the
outpatient drug-free modality. For example, female clients remained less time in
the programs that accepted only public funding than in the programs that accepted
both public and private funding. Male clients remained in the treatment an
average of 25.3 fewer days than female clients in drug-free programs that only
accepted public fund, but stayed about the same time as females if the programs
received mixed funding.
PMID- 9758015
TI - Short- and long-term effects of a pilot prevention program to reduce alcohol
consumption.
AB - This study examined the effects of a brief, pilot alcohol prevention intervention
for 211 disadvantaged 6th grade school children at posttest and 1-year follow-up.
Process data indicated that the intervention was successfully implemented and
well received by youth and parent/guardian participants. ANCOVA analyses
indicated a significant difference on alcohol use frequency for drinking subjects
at 1-month posttest, with less frequent use reported by intervention subjects
than subjects receiving the minimal control materials, F(1,22) = 5.37, p = .03.
No differences were found between intervention and control subjects on alcohol
use measures at 1-year follow-up. Critical issues to be resolved related to the
success of future prevention research and practice are discussed.
PMID- 9758017
TI - Comments on "The moral economies of homeless heroin addicts: confronting
ethnography, HIV risk, and everyday violence in San Francisco shooting
encampments," by Phillippe Bourgois.
PMID- 9758016
TI - The moral economies of homeless heroin addicts: confronting ethnography, HIV
risk, and everyday violence in San Francisco shooting encampments.
AB - Ethnographic immersion among homeless heroin addicts in San Francisco documents
far more risky practices than the public health literature routinely reports. The
logics of street-based income-generating strategies and the moral economy of
social networking among self-identified "dope fiends" results in almost daily
shares of drug preparation paraphernalia. Public health researchers need to
reconceptualize their psychological behaviorist paradigm of "individual health
risk behavior" because the pragmatics of income-generating strategies and the
social symbolic hierarchies of respect, identity, and mutual dependence shape
risky behavior. The explanatory potentials and the applied interventions that
participant-observation anthropological approaches could bring to epidemiological
public health research have not been utilized effectively in the field of HIV
prevention and substance use. The accuracy of quantitative public health
databases and our understanding of the who/why/how/where of HIV infection could
be improved by a cross-methodological dialogue with participant-observation
fieldworkers and by a greater theoretical sophistication with respect to power,
violence, and extreme social marginalization.
PMID- 9758018
TI - Comments on "The moral economies of homeless heroin addicts: confronting
ethnography, HIV risk, and everyday violence in San Francisco shooting
encampments," by Phillippe Bourgois.
PMID- 9758019
TI - Comments on "The moral economies of homeless heroin addicts: confronting
ethnography, HIV risk, and everyday violence in San Francisco shooting
encampments," by Phillippe Bourgois.
PMID- 9758020
TI - Comments on "The moral economies of homeless heroin addicts: confronting
ethnography, HIV risk, and everyday violence in San Francisco shooting
encampments," by Phillippe Bourgois.
PMID- 9758021
TI - Comments on "The moral economies of homeless heroin addicts: confronting
ethnography, HIV risk, and everyday violence in San Francisco shooting
encampments," by Phillippe Bourgois.
PMID- 9758022
TI - Comments on "The moral economies of homeless heroin addicts: confronting
ethnography, HIV risk, and everyday violence in San Francisco shooting
encampments," by Phillippe Bourgois.
PMID- 9758023
TI - The metabolic fate of long-term inhaled nitric oxide.
AB - PURPOSE: The fate of inhaled nitric oxide (NO) has not been precisely defined in
critically ill patients. This study aimed at defining the effects of long-term NO
inhalation on circulating NO byproduct levels. MATERIAL AND METHODS: During NO
therapy, plasma and urine from 13 critically ill patients were sampled daily for
determination of the stable byproducts of NO (nitrite [NO2-] and nitrate [NO3-].
Routine monitoring data included inhaled NO concentration, hemodynamic
parameters, arterial blood gases, creatinine clearance, and C-reactive protein.
RESULTS: For the first 24 hours of NO inhalation (6.3+/-1.1 ppm), NO3- plasma
concentration increased (from 13.3+/-5.4 to 52.3+/-17.6 micromol/L), but NO2-
plasma concentration was not affected. The NO3- plasma concentration was
correlated with the C-reactive protein level, the inhaled NO concentration. Renal
excretion of NO metabolites was unaltered by NO inhalation. The NO3
concentrations returned to baseline when NO therapy was discontinued. CONCLUSION:
Long-term NO inhalation was associated with a consistent increase in the NO3-
plasma concentration. NO byproducts may be implicated in the systemic effects
associated with this treatment.
PMID- 9758024
TI - Cerebral blood flow is proportional to cardiac index in patients with septic
shock.
AB - PURPOSE: In patients with septic shock, the cardiac index is often increased.
Maldistribution of blood flow and regional hypoperfusion has been implicated as a
key factor in the pathogenesis of organ dysfunction in these patients. We have
investigated the relationship between cerebral blood flow and cardiac index in
patients with septic shock. MATERIALS AND METHODS: We used Doppler ultrasound
techniques to investigate limb and carotid blood flow in 15 patients with septic
shock and 9 nonseptic controls. RESULTS: In the nonseptic control patients,
common femoral and brachial blood flow were proportional to cardiac index (r=0.73
and 0.76; P=.038 and .017, respectively) reflecting a protective redistribution
of flow to more vital organs. However, this relationship was absent in patients
with septic shock (r=0.23 and 0.21). Furthermore, in the septic patients but not
the nonseptic controls, cerebral blood flow was correlated with the cardiac index
(r=0.66, P < .05 vs r=-0.36, NS in nonseptic controls). Carotid flow was
independent of mean arterial pressure, PaCO2 and PaO2 in patients with septic
shock. CONCLUSIONS: These data are consistent with a loss of autoregulation of
cerebral blood flow and a change in the control of limb blood flow in humans with
septic shock.
PMID- 9758025
TI - Optimal pressure support level for beginning weaning in patients with COPD:
measurement of diaphragmatic activity with step-by-step decreasing pressure
support level.
AB - PURPOSE: The study objective was to determine an "optimal" individual pressure
support (PS) level for beginning weaning with PS ventilation in patients with
chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: Eleven COPD
patients intubated and ventilated for acute respiratory failure and judged ready
for weaning were studied. The technique consisted of lowering the PS level from a
point that was characteristic for each patient and measurable under controlled
mechanical ventilation, after setting the ventilator as recommended for COPD
patients judged ready for weaning, that is, peak inflation pressure (PIP). This
determination was based mainly on exploring the diaphragm with an
electromyographic technique by defining the optimal PS level as the lowest PS
level associated with no EMG evidence of diaphragmatic stress. Diaphragmatic
electromyographic activity (diEMG) was recorded by a bipolar esophageal electrode
(Disa-Denmark), and the high-frequency electrical component/low-frequency ratio
(H/L) was calculated. The reference H/L was determined during a few spontaneous
ventilatory cycles. Muscle stress was defined as a greater than 20% reduction in
H/L compared with the reference value. RESULTS: Optimal PS levels ranged from 4
to 24 cm H2O with a mean of 14+/-6 cm H2O. Two patients with optimal PS level at
4 cm H2O did not require weaning and were quickly extubated. For the nine other
patients, optimal PS levels were found to be 70% of PIP; in none was it necessary
during weaning to use PS levels higher than individual optimal PS levels.
CONCLUSIONS: Optimal PS level established with diEMG monitoring seems to be a
useful index for beginning weaning in the PS ventilation mode in COPD patients.
The hypothesis of beginning weaning with a PS level equal to 70% of PIP needs to
be tested.
PMID- 9758026
TI - Effect of continuous lateral rotational therapy on lung mucus transport in
mechanically ventilated patients.
AB - PURPOSE: Continuous lateral rotational therapy (CLRT) <40 degrees is a method of
altering the position of the ventilated patient to help clear secretions from the
lung. CLRT has not been shown to reduce the incidence of atelectasis or pneumonia
but potentially offers a way to maximize positional drainage in these patients
without producing adverse effects. Treatment intervention, bracketed by two
(nonrotational) control periods. The purpose of this study was to determine if
CLRT alters mucus transport in critically ill, intubated patients in the
intensive care unit of a teaching hospital. MATERIALS AND METHODS: Thirteen
critically ill, but stable, mechanically ventilated patients, mean age 74 years,
were enrolled. They were placed supine on a Biodyne bed (KCI, San Antonio, Texas)
and pressures in the cushions adjusted to patient's weight. A radiolabeled
aerosol was delivered by bagging for 2 to 3 minutes and repeated measurements of
lung radioactivity were obtained by imaging of the thorax over the following 3
hours. A 90-minute period of rotation of the bed, 30 degrees to either side was
preceded and followed by two 45-minute control periods during which the patient
remained supine and stationary on the bed. Coughs and suctions were recorded and
blood gases obtained pre and post study. RESULTS: (1) The mucous clearance was
slower than that reported in normal subjects and in ambulatory patients with
COPD; (2) there was a slight, but not significant, increase in clearance during
CLRT; (3) clearance reverted to pre-oscillation levels following therapy. Lack of
significant effect may be attributed to too shallow an angle for rotation or too
short an intervention period. CONCLUSION: Positional drainage effected by short
duration CLRT did not appear to stimulate significant mucous removal from the
lung in critically ill patients but also did not cause any adverse effects.
PMID- 9758027
TI - Volume recruitment and oxygenation in pulmonary edema: a comparison between HFOV
and CMV.
AB - PURPOSE: In acute lung injury, edema floods alveoli decreasing mean lung volume
(MLV) and increasing pulmonary venous admixture (Ova/Qt). We reasoned that a
ventilatory strategy that uses large tidal volumes (VT) might recruit volume
differently than a strategy that uses very small VT (high-frequency oscillatory
ventilation, HFOV) which may require an inflation maneuver to total lung capacity
(TLC) for full recruitment. MATERIALS AND METHODS: We studied six dogs with
pulmonary edema induced by oleic acid injury and compared HFOV with conventional
mechanical ventilation (CMV). Increasing mean airway opening pressure (Pao) from
6 to 14 cm H2O raised MLV from 932+/-162 to 1,550+/-210 mL and from 872+/-145 to
1,242+/-192 mL during CMV and HFOV, respectively, whereas Qva/Qt decreased from
24.1+/-8.5 to 9.3+/-4.3% and from 42.2+/-6.8 to 30.4+/-9.3%. We repeated our
measurements at a Pao of 14 cm H2O after an inflation maneuver to TLC. RESULTS:
Intlation to TLC recruited additional lung volume and decreased Qva/Qt further
only during HFOV. After an inflation to TLC, we observed a rapid isobaric volume
loss from the deflation limb of the pressure-volume curve during both CMV and
HFOV. CONCLUSIONS: We conclude that after oleic acid injury in dogs pressure
volume hysteresis has two components: a recruitable portion associated with gas
exchange improvement and a nonrecruitable portion. At the level of PEEP used in
this study (8.5 cm H2O), full lung recruitment during HFOV required inflation to
TLC, whereas during CMV it was accomplished by the relatively large VT.
PMID- 9758028
TI - Partial liquid ventilation decreases albumin leak in the setting of acute lung
injury.
AB - PURPOSE: This study evaluated the ability of partial liquid ventilation (PLV, gas
ventilation of the perfluorocarbon-filled lungs) to reduce the amount of lung
albumin leak present in the setting of acute lung injury. MATERIALS AND METHODS:
An experimental controlled, randomized design was used. All studies were
performed in the liquid ventilation laboratories at the University of Michigan
Medical Center. Twenty-five Sprague-Dawley male rats 500+/-50 g were divided into
five experimental groups: (1) CVF only (n=5), animals were cobra venom factor
(CVF) lung injured; (2) PLV-CVF (n=5) animals received perflubron and PLV before
CVF lung injury; (3) CVF-PLV (n=5) animals received PLV after CVF lung injury;
(4) PLV only (n=5) animals underwent partial liquid ventilation without lung
injury; and (5) Gas only (n=5) animals underwent gas ventilation without lung
injury. In all groups iodinated bovine serum albumin (125I-BSA) was delivered by
intravenous injection along with CVF or a saline placebo. RESULTS: When the CVF
animals were compared with all other groups, a decrease in albumin leak was
observed for all groups when compared with the CVF only controls (P < .001 by
ANOVA; CVF only=1.22+/-0.12 versus PLV-CVF=0.46+/-0.08, P < .001; CVF-PLV=0.70+/
0.25, P < .001; PLV only=0.22+/-0.01, P < .001; Gas only=0.17+/-0.02, P < .001).
CONCLUSIONS: These data suggest that intratracheal instillation of
perfluorocarbon before or after induction of lung injury results in a reduction
in pulmonary albumin leak.
PMID- 9758029
TI - Surrogates' agreement with patients' resuscitation preferences: effect of age,
relationship, and SUPPORT intervention. Study to Understand Prognoses and
Preferences for Outcomes and Risks of Treatment.
AB - PURPOSE: The purpose of this study was to evaluate an intervention to improve
patient-surrogate agreement on end-of-life resuscitation preferences. MATERIALS
AND METHODS: Seven hundred seventeen patients with a 50% 6-month survival rate
and their surrogate decision-makers were recruited for a randomized clinical
trial from five teaching hospitals participating in the Study to Understand
Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT).
Intervention patients (n=386) were assigned specially trained nurses who spent
extra time with patients and families explaining prognoses and treatments.
Control patients (n=331) received usual care. Patient preferences and surrogate's
perception of those preferences at pre- and post-intervention interviews were
compared. RESULTS: Agreement between patients and surrogates was 75.0% at the day
3 interview and 79.6% at the month 2 interview, increasing 4.6% (95% CI: 0.1%,
9.1%). Improvements in agreement from day 3 to month 2 were seen equally in both
study groups. A multivariable analysis verified that the intervention did not
have an effect on agreement and indicated a decrease in agreement among older
patients and among surrogates not in the immediate family. CONCLUSIONS: The
SUPPORT intervention was not successful in increasing agreement between patients
and surrogates. Because of the complex issues involved in end-of-life decision
making, a more aggressive intervention may be needed. Other findings suggest that
improvements in communication are particularly needed when patients are older and
when the surrogate is not a patient's immediate relative.
PMID- 9758030
TI - Thoracocardiography: noninvasive monitoring of left ventricular stroke volume.
AB - PURPOSE: Thoracocardiography noninvasively monitors global stroke volume by
inductive plethysmographic recording of ventricular volume curves as previously
validated by thermodilution. Our purpose was to investigate the potential of
thoracocardiography to individually assess stroke volume of the left ventricle.
We hypothesized that curves predominantly reflecting left ventricular volume
could be obtained by recording waveforms from thoracocardiographic transducers
placed at various levels around the chest, and by identifying their origin as the
left ventricle if mean expiratory exceeded mean inspiratory stroke volumes during
spontaneous breathing. MATERIALS AND METHODS: Stroke volumes obtained by
thoracocardiography in normal subjects were compared beat by beat with estimates
derived from simultaneous measurements of left ventricular cavity stroke area by
echocardiography with automatic boundary detection. Changes in respiratory
variations of stroke volumes were analyzed during spontaneous breathing at fixed
rate and tidal volume, during mechanical ventilation, and resistive loaded
breathing. RESULTS: In 170 comparisons of beat-by-beat stroke volumes, 89% of
thoracocardiographic fell within +/-20% of echocardiographic estimates. Changes
in tidal volume, resistive loaded breathing, and mechanical ventilation induced
respiratory variations of thoracocardiographic derived stroke volumes consistent
with the known effect of respiratory changes in intrapleural pressure on left
ventricular stroke volumes. CONCLUSIONS: The results suggest that
thoracocardiography noninvasively tracks changes in left ventricular stroke
volumes. Their absolute value may also be monitored if an initial calibration by
an independent technique, such as echocardiography, is performed.
PMID- 9758031
TI - Equilibrium vapour pressure of mercury from dental amalgam under loading
conditions.
AB - Earlier studies have failed to establish a consensus on the amount of mercury
vapour released from dental amalgam restorations. The purpose of this study was
to accurately and quantitatively measure the equilibrium mercury vapour pressure
from dental amalgam. The vapour pressure was measured using a quartz crystal
microbalance as a function of the load from 0-5.4 MPa. Auger spectra were
collected of the as-formed and argon ion sputter cleaned dental amalgam surface.
For the as-formed surface the mercury vapour density is zero with no load and
increases to 0.6 microg m(-3) at 5.4 M Pa. Following cleaning the mercury, vapour
density increased to a maximum value of 15 microg m(-3). The Auger spectra of the
as-formed surfaces were dominated by features associated with carbon and oxygen.
These spectral results in concert with the mercury vapour density measurements
indicate that the oxide film on the as-formed surfaces inhibited the release of
mercury vapour. The results of this experiment provide an upper limit for the
amount of mercury vapour released by dental amalgams. Under conditions simulating
the oral cavity this value would be reduced by oxides that form on the surface of
dental amalgam restorations.
PMID- 9758032
TI - In vivo osteogenesis assay: a rapid method for quantitative analysis.
AB - A quantitative in vivo osteogenesis assay is a useful tool for the analysis of
cells and bioactive factors that affect the amount or rate of bone formation.
There are currently two assays in general use for the in vivo assessment of
osteogenesis by isolated cells: diffusion chambers and porous calcium phosphate
ceramics. Due to the relative ease of specimen preparation and reproducibility of
results, the porous ceramic assay was chosen for the development of a rapid
method for quantitating in vivo bone formation. The ceramic cube implantation
technique consists of combining osteogenic cells with 27-mm3 porous calcium
phosphate ceramics, implanting the cell-ceramic composites subcutaneously into an
immuno-tolerant host, and, after 2-6 weeks, harvesting and preparing the ceramic
implants for histologic analysis. A drawback to the analysis of bone formation
within these porous ceramics is that the entire cube must be examined to find
small foci of bone present in some samples; a single cross-sectional area is not
representative. For this reason, image analysis of serial sections from ceramics
is often prohibitively time-consuming. Two alternative scoring methodologies were
tested and compared to bone volume measurements obtained by image analysis. The
two subjective scoring methods were: (1) Bone Scale: the amount of bone within
pores of the ceramic implant is estimated on a scale of 0-4 based on the degree
of bone fill (0=no bone, 1=up to 25%, 2=25 to 75%, 4=75 to 100% fill); and (2)
Percentage Bone: the amount of bone is estimated by determining the percentage of
ceramic pores which contain bone. Every tenth section of serially sectioned cubes
was scored by each of these methods under double-blind conditions, and the Bone
Scale and Percentage Bone results were directly compared to image analysis
measurements from identical samples. Correlation coefficients indicate that the
Percentage Bone method was more accurate than the Bone Scale scoring method. The
Bone Scale scoring method gave an r2=0.767 while the Percentage Bone method gave
a value of 0.902. These results indicate that scoring ceramic cubes by the
percentage of pores containing bone gives a result that corresponds to image
analysis measurements at nearly a 90% confidence level. Thus, the Percentage Bone
method of scoring is an accurate and relatively quick scoring method for in vivo
bone formation.
PMID- 9758033
TI - Composite technology in load-bearing orthopaedic implants.
AB - Composite materials have been widely promoted as possible orthopaedic
biomaterials but to date have found few successful commercial applications, due
to the many challenging problems presented by their design, fabrication and
testing. The range of possible composite biomaterials is reviewed, together with
the possible methods of fabrication and the limitations that these place on the
design of composite components. The use of composite materials allows many new
design possibilities, but this freedom of design requires a clearer understanding
of the objectives and constraints on the design process. The testing of composite
components also presents many challenging problems, which are not adequately
addressed by existing standards developed for testing conventional monolithic
materials. The interaction of composite materials with the body is more complex
than that of the component materials, and the prediction of their long-term
mechanical performance also presents many intractable difficulties. However,
despite these challenges composite materials are likely to prove invaluable in
the future development of orthopaedics.
PMID- 9758034
TI - Light-induced tailoring of PEG-hydrogel properties.
AB - We have previously reported (Andreopoulos et al. J Am Chem Soc 118 (1996) 6235
6240) the synthesis of hydrogels via the photopolymerization of water-soluble PEG
molecules. In this paper, PEG-hydrogel membranes were prepared by the irradiation
(> 300 nm) of aqueous solutions of photosensitive 4-armed PEG (nominal molecular
weight of 20000), in the absence of photo-initiators. The hydroxyl termini of the
PEG's were functionalized with cinnamylidene acetate groups to form
photosensitive PEG macromers (PEG-CA), which upon irradiation (>300 nm) formed
crosslinks between adjacent cinnamylidene groups resulting in highly crosslinked
networks (hydrogels) (Andreopoulos et al. J Am Chem Soc 118 (1996) 6235-6240).
The hydrogel membranes were highly swellable with equilibrium volume fractions
ranging from 0.02 to 0.05. Their swellability was a function of irradiation light
(>300 nm) and degree of modification of the PEG molecules. The effect of light on
the permeation fluxes of myoglobin (Mb), hemoglobin (Hb), and lactate
dehydrogenase-L (LDH) through PEG membranes was also assessed and the diffusion
coefficients of the proteins were determined accordingly. The PEG-CA membranes
exhibited photoscissive behavior upon exposure to UV irradiation (254 nm).
Therefore, UV light was used as a trigger to control the mesh size of the
membranes, and thereby the permeation fluxes of Mb, Hb, and LDH. Equilibrium
swelling experiments with membranes prepared under different irradiation
conditions were performed, and the Flory-Huggins model was utilized to determine
the mesh size and the average molecular weight between crosslinks of the
synthesized hydrogels.
PMID- 9758035
TI - The use of SIMS, XPS and in situ AFM to probe the acid catalysed hydrolysis of
poly(orthoesters).
AB - Due to poly(orthoesters) being susceptible to acid catalysed hydrolysis, these
polymers have attracted considerable interest for the controlled delivery of
therapeutic agents within biodegradable matrices. The pH-sensitivity of the poly
(orthoesters) has lead to several drug delivery systems being developed, whose
rate of drug release is predominantly controlled by the rate of polymer
hydrolysis. This study reports on the use of X-ray photoelectron spectroscopy
(XPS), secondary ion mass spectrometry (SIMS), and atomic force microscopy (AFM)
in a multitechnique approach to probe the effect of acid catalysed hydrolysis at
the interface of poly(orthoesters). The molecular specificity of SIMS was
successfully employed, suggesting that the preferred mechanism for hydrolysis was
via the cleavage of an exocyclic alkoxy bond in the 3,9,-diethylidene-2,4,8,10
tetraoxaspiro [5,5] undecane(DETOSU) unit. The resulting change in the surface
chemical structure of the partially hydrolysed poly(orthoester) is such that it
was not detectable by XPS analysis. Images acquired from an in situ AFM study of
the hydrolysis ofa poly(orthoester), showed changes in the surface morphology,
seen as the formation of pits, and an overall thinning of the polymer film. The
use of SIMS, XPS and AFM has enabled changes in surface chemistry to be compared
with changes in surface morphology. These complementary data, on the behaviour of
the polymer during degradation have important implications for the further design
of novel biodegradable materials.
PMID- 9758036
TI - A hydrophobic interaction site for lysozyme binding to polyethylene glycol and
model contact lens polymers.
AB - Proton nuclear magnetic resonance (1H-NMR) spectroscopy is used to identify a
preferred binding site for uncharged hydrophilic polymers on the surface of hen
egg-white lysozyme. Chemical shift titrations show that exchangeable proton
signals from amino acids Arg-61, Trp-62, Trp-63, Arg-73, Lys-96 and Asp-101 are
selectively perturbed upon binding of poly(ethylene oxide), poly(ethylene glycol)
and poly(ethylene-co-propylene oxide). The greatest binding-induced chemical
shift changes are observed for Trp-62, Arg-61 and Arg-73 at the edge of the
active site cleft of the protein, consistent with a predominantly hydrophobic
interaction mode involving the polymer ethylene moieties. The more hydrophilic
species poly(dihydroxypropyl methacrylate) causes similar but substantially
smaller chemical shift effects than the other polymers, confirming the nature of
the interaction. A dissociation constant of 76+/-5 mM is determined for the
poly(ethylene glycol)-lysozyme complex. The relatively low affinity of the
protein-polymer interactions compared to oligosaccharide substrate binding
suggests that lysozyme activity is minimally affected by these materials.
PMID- 9758037
TI - In vivo UHMWPE biodegradation of retrieved prosthesis.
AB - Sixty-two ultra high molecular weight polyethylene prosthetic components (PEs)
(31 tibial plateaux and 31 cups), sterilised by gamma rays or ethylene oxide
(EtO), were retrieved after 1-12 years depending on different medical reasons and
were studied by FTIR spectroscopy with derivatisation of oxidised species.
Esters, acids and hydroperoxides were found under the surface of the EtO
sterilised PEs up to 2 mm depth. The behaviour of gamma ray sterilised PEs is
more complex due to the oxidation following the sterilisation process. Ester and
acid formation might arise from the diffusion of components of synovial liquid or
from the oxidation process, whereas hydroperoxide formation is thought to be due
to the oxidation. Abrasion and delamination process is discussed considering the
topological distribution of degradation products.
PMID- 9758038
TI - Biological evaluation of biphasic calcium phosphate ceramic vertebral laminae.
AB - An artificial vertebral lamina with a dense inside surface and porous outside
part, fabricated with a biphasic calcium phosphate (70% hydroxyapatite/30%
tricalcium phosphate) (HA-TCP) ceramic (abbr. CVL), was evaluated by animal
experiments. The animal experiments showed that at half a month postoperation, no
bone formation occurred on the macropore surfaces of the implants, however,
fibrous connective tissues and blood vessels had grown into the macropores,
contributing to the early fixation of the CVLs. The degradation of TCP phase was
detected through X-ray diffraction (XRD); in the meanwhile, needle-like and plate
like crystals were found in the materials through scanning electron microscopy
(SEM), and infrared spectroscopy (IR) observations showed that the carbonate
apatites similar to bone apatites began to occur in the materials. At one month
postoperation, the degradation of the TCP phase became moderate, new bone began
to grow into the porous structures of the implants, and further degradation of
the implants provided rich Ca and P ions for new bone formation. The newly formed
bone in the macropores of the implants increased with implantation time. At one
year postoperation, the implant was completely fused with natural bone on the
interfaces between them, new bone had grown into most of the porous structures of
the implants, and a natural bone tissue layer formed on the inside surface of the
artificial vertebral lamina. The new bone tissue layer played a more effective
role in protecting the spinal cord and improving the spinal stability in the
later implantation time.
PMID- 9758039
TI - Early peripheral nerve healing in collagen and silicone tube implants:
myofibroblasts and the cellular response.
AB - Injuries to peripheral nerves innervating a limb cause paralysis, and can
necessitate amputation. The inability of the nerves to regenerate spontaneously
and the limitations of autograft procedures led to the development of treatments
involving insertion of the nerve ends into prosthetic tubular devices. Previous
work showed that 'entubulation' of the nerve ends in a silicone tube containing a
specific porous, resorbable collagen-GAG (CG) copolymer, serving as an analog of
extracellular matrix, improved regeneration compared to an empty silicone tube.
However, long-term treatment with silicone tubes produced constriction that
caused partial degradation of the regenerated axons; for this and other reasons,
implementation of a nondegradable tube may require a second surgical procedure
for removal. In this study the silicone tube was replaced with porous and non
porous collagen tubes in order to produce fully degradable devices. CG-filled
collagen tubes and controls (CG-filled silicone tubes and empty collagen and
silicone tubes) were implanted in a 10-mm gap in the rat sciatic nerve, with
three rats in each group. The regeneration was evaluated after six weeks using
light microscope images of cross sections of the nerve that were digitized and
analyzed. Histograms of the diameters of the axons were generated and compared.
The cellular response to the implanted biomaterials was assessed histologically,
and immunohistochemistry was performed using an antibody to alpha-smooth muscle
actin in order to determine the presence of myofibroblasts (contractile cells).
Axonal regrowth was comparable in porous collagen, non-porous collagen, and
silicone tubes filled with a CG matrix. These results support the implementation
of a degradable collagen tube in place of a silicone device. Confirming earlier
work, regeneration through the silicone and collagen tubes was enhanced by the CG
copolymer, compared to empty tubes. A notable finding was a continuous layer of
myofibroblasts on the surfaces of all of the six silicone tube prostheses, but on
the inner surface of only one of six collagen tubes (Fisher's exact tests; P <
0.01). This is the first report of contractile capsules around silicone tubes,
and supports the use of degradable collagen tubes in peripheral nerve
regeneration. Macrophages were found bordering both the silicone and collagen
tubes, and in the case of the collagen tubes, appeared to be participating in the
regulation of the tubes.
PMID- 9758041
TI - Reverse transcription-polymerase chain reaction and immunohistochemical study of
the expression of fibronectin mRNA in human submandibular salivary gland.
AB - The alternative expression of fibronectin mRNA in submandibular salivary glands
was analysed using three groups of polymerase chain reaction probes to amplify
the cell-binding domain (CBD), and the extra domain (ED)-A and ED-B exon regions
in five normal human adults. The fibronectin CBD region was fairly well expressed
in the salivary gland while less than trace amounts of ED-A and ED-B exons were
expressed. Immunohistochemical staining with an antihuman plasma fibronectin
monoclonal antibody, which recognized specifically the CBD region, demonstrated
definite positive cytoplasmic staining in the duct-cell area. On the other hand,
an anticellular fibronectin ED-A-specific monoclonal antibody was very low
positive in duct cells. The results suggest that salivary fibronectin is
synthesized in the submandibular salivary gland only, and does not include the ED
A segment. Furthermore, duct cells also produced fibronectin without ED-A.
PMID- 9758040
TI - Three-dimensional culture of rat calvarial osteoblasts in porous biodegradable
polymers.
AB - Neonatal rat calvarial osteoblasts were cultured in 90% porous, 75:25 poly(DL
lactic-co-glycolic acid) (PLGA) foam scaffolds for up to 56 days to examine the
effects of the cell seeding density, scaffold pore size, and foam thickness on
the proliferation and function of the cells in this three-dimensional
environment. Osteoblasts were seeded at either 11.1 x 10(5) or 22.1 x 10(5) cells
per cm2 onto PLGA scaffolds having pore sizes in the range of 150-300 or 500-710
microm with a thickness of either 1.9 or 3.2 mm. After 1 day in culture, 75.6 and
68.6% of the seeded cells attached and proliferated on the 1.9 mm thick scaffolds
of 150-300 microm pore size for the low and high seeding densities, respectively.
The number of osteoblasts continued to increase throughout the study and
eventually leveled off near 56 days, as indicated by a quantitative DNA assay.
Osteoblast/foam constructs with a low cell seeding density achieved comparable
DNA content and alkaline phosphatase (ALPase) activity after 14 days, and
mineralization results after 56 days to those with a high cell seeding density. A
maximum penetration depth of osseous tissue of 220+/-40 microm was reached after
56 days in the osteoblast/foam constructs of 150-300 microm pore size initially
seeded with a high cell density. For constructs of 500-710 microm pore size, the
penetration depth was 190+/-40 microm under the same conditions. Scaffold pore
size and thickness did not significantly affect the proliferation or function of
osteoblasts as demonstrated by DNA content, ALPase activity, and mineralized
tissue formation. These data show that comparable bone-like tissues can be
engineered in vitro over a 56 day period using different rat calvarial osteoblast
seeding densities onto biodegradable polymer scaffolds with pore sizes in the
range of 150-710 microm. When compared with the results of a previous study where
similar polymer scaffolds were seeded and cultured with marrow stromal cells,
this study demonstrates that PLGA foams are suitable substrates for osteoblast
growth and differentiated function independent of cell source.
PMID- 9758042
TI - Effects of inositol hexasulphate, a casein kinase inhibitor, on dentine
phosphorylated proteins in organ culture of mouse tooth germs.
AB - To study the effects of impaired protein phosphorylation on dentine formation and
mineralization, inositol hexasulphate, an intracellular type I and type II casein
kinase inhibitor, was used in an in vitro organotypic culture system. Mandibular
first molar tooth germs were dissected from 18-day-old mouse embryos and cultured
for 11 days with and without inositol hexasulphate at different concentrations.
At 0.04-0.08 mM inhibitor, cellular alterations were not detected. Dentine
displayed the characteristic purple-blue colour when Stains all, a specific stain
for extracellular phosphoproteins, was used. At 0.1 mM, dentine failed to stain
and mineralization did not occur, as seen from the von Kossa method. The presence
of numerous lysosome-like vesicles inside cells indicated that the experiment was
at the limits of cytotoxicity; higher concentrations induced severe cellular
alterations. Therefore, quantitative radioautography was carried out on germs
treated or not with the inhibitor at 0.1 mM. [33P]-phosphate incorporation showed
that grain density in inhibited germs compared with that in control germs was
about double in odontoblasts and half in the predentine/dentine compartment. In
the presence of inositol hexasulphate the incorporation of [3H]serine into
odontoblast cell bodies was unchanged between 2 and 24 h while in
predentine/dentine, grain density was higher between 1 and 4 h, and reduced at 24
h. Both with [33P]phosphate and [3H]serine, labelling was seen throughout the
porous dentine formed in vitro and not as a band located at the
predentine/dentine junction, as is the case in vivo. With [3H]proline, in the
presence of the inhibitor, a small reduction of grain density occurred in cell
bodies, no significant difference was seen between 1 and 4 h in
predentine/dentine, and more silver grains were present after 24 h both in cells
and in the matrix. The radioautographic data support the view that the inhibitor
interacts mostly with post-transductional phosphorylation and does not alter
significantly other cell synthetic pathways and functions. Finally, the
experiments presented here confirm that phophorylated proteins have a key role in
dentine mineralization.
PMID- 9758044
TI - Factors affecting the development of carious lesions in bovine teeth in vitro.
AB - This study aimed to determine the effect of temperature, duration of exposure,
position on enamel surface, and type of demineralization solution on the
production of caries-like lesions in bovine enamel in vitro, and to establish the
conditions for the formation of artificial caries in bovine enamel. Caries-like
lesions were produced in incisal, middle and cervical sites on enamel samples,
with either an acidified hydroxyethylcellulose gel system or a partially
saturated acidic buffer solution at either 20 degrees C or 37 degrees C for 3, 4,
or 5 days. Lesion variables (mineral loss/lesion depth) were quantified. Regular
subsurface lesions were produced in all specimens in acidic buffer solution
within 3 days at either temperature. In gel, caries-like lesions were produced in
62% of the specimens at 37 degrees C and in 49% at 20 degrees C, while the
remaining specimens were either eroded or softened. Mineral loss and lesion depth
were significantly greater with buffer than with gel, and with increased length
of exposure in either solution. There were no significant differences in either
variable with position or temperature in either solutions, though numerically
both variables were greater at the cervical site, and at 37 degrees C in either
solution. It was concluded that caries-like lesions can be consistently produced
in bovine enamel with a partially saturated acidic buffer solution at 20 degrees
C or 37 degrees C within 3 days.
PMID- 9758043
TI - Localization of atrial natriuretic peptide receptors in the rat tongue and hard
palate.
AB - Atrial natriuretic peptide (ANP) receptors were characterized in rat oral mucosa
using quantitative in vitro autoradiography and activation of particulate
guanylyl cyclase (GC) by natriuretic peptides. Competition-binding analysis
performed by quantitative in vitro autoradiography demonstrated specific
[125I]rANP(1-28) binding sites in the tongue and hard palate. The precise
location of this binding was revealed on the basal and parabasal cells of the
epithelia by microautoradiography. The dissociation constant (Kd) and maximal
binding capacity (Bmax) of these sites were 3.34+/-1.35 nM and 2.71+/-2.21
fmol/mm2 on the epithelium of the tongue, and 4.09+/-1.52 nM and 3.45+/-3.01
fmol/mm2 on the epithelium of the hard palate, respectively. Receptor subtypes
were characterized by competition with des [Gln18, Ser19, Gly20, Leu21, Gly22]
ANP(4-23) (C-ANP), a specific ligand for the clearance receptor (NPR-C). These
binding sites were displaced by C-ANP with inhibition constant (Ki) of 8.96+/
3.18 nM and Bmax of 2.89+/-2.45 fmol/mm2 on the epithelium of the tongue, and Ki
of 9.12+/-2.71 nM and Bmax of 3.08+/-2.94 fmol/mm2 on the epithelium of the hard
palate, respectively. Production of cyclic GMP by particulate GC in the
epithelial membranes of the tongue and hard palate was stimulated by rANP(1-28),
porcine brain natriuretic peptide (BNP)(1-26), and C-type natriuretic peptide
(CNP)(1-22) in a dose-dependent manner. These results indicate that ANP-binding
sites in the epithelium of the tongue and hard palate are mainly clearance
receptors (NPR-C) but biological receptors (NPR-A and/or NPR-B) with GC activity
are also present, and suggest that ANP may have a role in the proliferation of
the oral epithelial cells, especially in the tongue and hard palate.
PMID- 9758045
TI - Discoloration of dental carious lesions (a review).
AB - The discoloration of dental carious lesions is a marked feature which has
received relatively little attention from dental researchers. In this short
review, possible causes are considered: the formation of Maillard pigments,
melanins, and lipofuscins, and the uptake of food dyes, metals, and bacterial
pigments. It is concluded that the Maillard reaction between proteins and small
aldehydes produced by bacteria probably accounts for the discoloration.
PMID- 9758046
TI - A pilot study of mineralization distribution in the cortical bone of the human
mandible.
AB - Twenty-three specimens from immediately anteroinferior to the mental foramen were
obtained from male and female, dentate and edentate, human mandibles.
Planoparallel 80 microm thick sections were prepared from the mandibular
specimens and computerized quantitative microradiography undertaken, which
allowed the production of mineralization frequency distribution curves and mean
mineralization. No differences in mean mineralization with age, sex, presence or
absence of dentition were found, but mineralization distribution curves indicated
differences between males and females. Within the age range and small sample size
examined (40-90 years) there were no age-related differences. There was a lower
level of mineralization distribution in the edentulous than the dentate mandible.
PMID- 9758047
TI - Geographic variations in the composition of ivory of the African elephant
(Loxodonta africana).
AB - Tracing the source of origin of illegal ivory will contribute to the
identification of poorly managed game parks and facilitate steps taken to prevent
the African elephant from becoming extinct. This study was aimed at establishing
a database on the composition of ivory obtained from elephant sanctuary areas in
Southern Africa. Fragments of elephant ivory from seven geographically distinct
areas in South Africa, Namibia and Botswana were analysed for inorganic and
organic content. A total of 20 elements was detected in the inorganic fraction of
ivory, some in concentrations as low as 0.25 microg/g. The concentrations of
calcium, phosphate, magnesium, fluoride, cobalt and zinc showed statistically
significant differences (p < 0.007) between ivory obtained from different
regions. Analyses of the organic fraction identified 17 amino acids. Ivory from
arid regions showed significantly lower proline plus hydroxyproline content and
under-hydroxylation of lysine residues. This study indicates that chemical
analyses of ivory could be beneficial in tracing the source of illegal ivory.
PMID- 9758048
TI - Scanning microradiographic studies of rates of in vitro demineralization in human
and bovine dental enamel.
AB - The aim was to measure frequently and with precision the local integrated mineral
loss through small areas of the natural surface of human and bovine enamel during
in vitro demineralization using an X-ray photon-counting system (scanning
microradiography). The method used was an adaptation of photographic longitudinal
microradiography in which the attenuation of X-rays through the enamel is
measured in the direction of acid attack, i.e., normal to the enamel surface. The
mass of mineral (assumed to be hydroxyapatite) per unit exposed area was measured
over 15 microm dia. circles at a series of positions as a function of time in
blocks of human and bovine enamel immersed in 0.1 mol/l acetic acid buffered to
pH 4.0 with NaOH. There was an initial period (approx. 45 h for human, approx. 75
h for bovine enamel) during which the mineral loss with time was sigmoidal,
followed by a nearly linear loss for the remainder of the experiment, in some
cases up to 500 h. The initial sigmoidal period may be due to properties of
surface enamel or be associated with the development of a surface layer overlying
subsurface demineralization. The essentially constant rate of mineral loss after
the surface layer has formed confirms earlier observations and is consistent with
a rate-limiting process occurring at the dissolving enamel surfaces of the
advancing front, and not by transport of ions within the lesion. Small
perturbations from a linear loss were seen, which were approximately periodic for
human enamel. The slope of the linear period was rather constant within one human
or bovine block, but variable between blocks without a clear distinction between
human and bovine enamel.
PMID- 9758049
TI - Cytokine production by cryopreserved human peripheral blood mononuclear cells in
response to periodontal pathogens.
AB - Freezing techniques provide a way of repeating and extending immunological assays
by using frozen portions of an individual's peripheral blood mononuclear cell
fraction. Earlier work shows that the lymphocytes that are stored frozen retain
their ability to respond to polyclonal B-cell activators, mitogens, superantigens
and bacterial extracts of oral interest. These studies extend previous findings
by determining cytokine production by lymphocytes following frozen storage for up
to 24 weeks. Production of interleukin (IL)-1beta, IL-2, IL-6, and tumour
necrosis factor (TNF)-beta by stimulated lymphocytes after cyropreservation was
not significantly different from those responses before storage, with one
exception: IL-6 production was negligible after 24 weeks' frozen storage when
thawed cells were cocultured with pokeweed mitogen. After stimulation with
extracts from Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans,
the proliferative capacity of the frozen cells was maintained as well as the
production of IL-1beta, IL-2, and IL-6. TNF-beta was not produced in response to
bacterial antigen stimulation. The ability of peripheral blood mononuclear cells
to retain functional activity after frozen storage should permit more effective
monitoring during longitudinal clinical studies and a better evaluation of
changes in cytokine production in patients with advanced periodontitis both
during and after treatment.
PMID- 9758051
TI - Prevention: toward a golden age.
PMID- 9758050
TI - Improved reproducibility of magnetic stimulation-evoked motor potentials in the
human masseter by a new method for locating stimulation sites on the scalp.
AB - In magnetic-stimulation studies where motor-evoked potentials (MEP) are measured
on different occasions, accurate relocation of the stimulation site on the scalp
is essential. Here a novel method of locating neural stimulation sites was tested
and the reproducibility of MEPs in the human masseter assessed. The heads of the
participants were immobilized in a plastic mask that incorporated a grid
overlying the left cerebral hemisphere. A figure-of-eight coil was oriented with
a micromanipulator. Electrodes were placed over the right masseter using a
standardized method. Two discrete sites on the grid were stimulated alternately
at threshold + 10% whilst participants clenched their teeth. Recordings were
repeated after the mask and electrodes had been removed and replaced. Within
individual participants, the latency and amplitude of the MEP were reproducible
between trials and when the mask and electrodes were replaced. The new method
appears to be accurate and practical when recording longitudinal MEP data in the
masseter.
PMID- 9758052
TI - Spread of vancomycin-resistant enterococci: why did it happen in the United
States?
AB - The question of why vancomycin-resistant enterococci (VRE) became epidemic in the
United States can be answered on at least three basic levels: (1) molecular and
genetic, (2) factors affecting host-microbe interactions, and (3)
epidemiological. This article will address the epidemiological issues and seek to
defend the assertion that, once VRE had evolved, its spread throughout hospitals
in the United States was all but assured. Nosocomial VRE outbreaks were reported
first in the mid- and late-1980s. Since that time, scientific reports of VRE have
increased over 20-fold. Among hospitals participating in the National Nosocomial
Infection Surveillance System from 1989 to 1997, the percentage of enterococci
reported as resistant to vancomycin increased from 0.4% to 23.2% in intensive
care settings and from 0.3% to 15.4% in non-intensive-care settings. Factors
leading to the spread of VRE in US hospitals include (1) antimicrobial pressure,
(2) sub-optimal clinical laboratory recognition and reporting, (3) unrecognized
"silent" carriage and prolonged fecal carriage, (4) environmental contamination
and survival, (5) intrahospital and interhospital transfer of colonized patients,
(6) introduction of unrecognized carriers from community settings such as nursing
homes, and (7) inadequate compliance with hand washing and barrier precautions.
Guidelines developed by the Centers for Disease Control and Prevention's Hospital
Infection Control Practices Advisory Committee address each of these factors. The
impact of these guidelines on the spread of VRE within individual institutions
has been variable, and the overall impact of the guidelines nationally is
unknown.
PMID- 9758053
TI - Spread of vancomycin-resistant enterococci: differences between the United States
and Europe.
AB - There are major differences in the epidemiology of vancomycin-resistant
enterococci (VRE) between the United States and Europe. In contrast with Europe,
VRE in the United States are resistant to many antibiotics, and there appears to
be less genetic variability among these isolates. European VRE of human origin
are usually susceptible to many other antibiotics and are highly polyclonal.
These clinical isolates have the same susceptibility profiles as VRE isolated
from animals. The differences in the spread of VRE between the United States and
Europe might be explained by the overconsumption of glycopeptides and other
antibiotics in hospitals in the United States and the use of avoparcin as a
growth promotor in Europe.
PMID- 9758054
TI - Methicillin-resistant Staphylococcus aureus and its relationship to antimicrobial
use: possible implications for control.
AB - The control of methicillin-resistant Staphylococcus aureus (MRSA) is still an
unresolved issue in numerous healthcare institutions worldwide. Guidelines for
the control of MRSA in hospitals focus on measures to control cross-transmission
and prevent colonization, but rarely specifically mention the control of
antimicrobial use. We reviewed the different types of evidence for a causal
relationship between MRSA and antimicrobial use by classifying them in four
categories: consistent associations, dose-effect relationships, concomitant
variations, and arguments to support a plausible biological model to explain this
relationship. Although the relative participation of cross-transmission and
antimicrobial selection pressure in the level of MRSA observed in a healthcare
setting remains to be determined, we found lines of evidence to support the
existence of a relationship between MRSA and antimicrobial use in each of the
four categories. This review points out the relative lack of studies specifically
designed to investigate this aspect of MRSA epidemiology and the need to
implement such studies quickly. In the meantime, the results presented here
should encourage the implementation of antimicrobial-use improvement programs in
hospitals in addition to existing infection control measures, which are still a
priority in countries with high MRSA prevalence.
PMID- 9758055
TI - Preventing antibiotic resistance using rapid DNA-based diagnostic tests.
AB - Improved diagnostic procedures should be an effective way to control infectious
diseases and the spread of antibiotic resistance. To do so, diagnostics will need
to be obtained within 1 hour of sampling and will require nucleic acid-based
amplification tests directly on the clinical specimen.
PMID- 9758056
TI - Comparative and library epidemiological typing systems: outbreak investigations
versus surveillance systems.
AB - A number of high-resolution molecular typing systems have been developed in
recent years. Their availability raises the new issues of selecting the method
(s) best suited for a particular purpose and interpreting and communicating
typing results. Most of the currently available methods are comparative only:
they allow testing of a sample of isolates for delineation of those closely
related from those markedly different in genomic backgrounds. This approach is
adequate for outbreak investigation, allowing determination of clonal spread in a
microenvironment and identification of the source of infection. Comparative
methods with sufficient resolution for most pathogens include restriction
fragment-length polymorphism (RFLP), pulsed-field gel electrophoresis (PFGE), and
arbitrarily primed and randomly amplified polymorphic DNA-polymerase chain
reaction (PCR) analysis. For surveillance systems, monitoring clonal spread and
prevalence in populations over extended periods of time requires library typing
systems. These must be standardized, must have a high throughput, and must use a
uniform nomenclature. Promising or validated methods include serotyping,
insertion sequence fingerprinting, ribotyping, PFGE, amplified fragment-length
polymorphism (AFLP), infrequent-restriction-site amplification PCR,
interrepetitive element PCR typing (rep-PCR) and PCR-RFLP of polymorphic loci.
PCR methods generating arrays of size-specific amplicons (AFLP, rep-PCR) can be
more reproducibly analyzed by using denaturing polyacrylamide gel or capillary
electrophoresis with automated laser detection. Binary probe typing systems
appear optimal and should be enhanced further through use of DNA chip technology.
In these systems, amplification of polymorphic regions is followed by solid-phase
hybridization with a reference panel of sequence-variant specific probes. The
resulting binary type results allow determination of reproducible, numeric
profiles. However, interpretation and nomenclature of typing results for large
scale surveillance purposes still require a better understanding of population
structure and microevolution of most microbial pathogens.
PMID- 9758057
TI - Modeling measles, mumps, and rubella: implications for the design of vaccination
programs.
AB - Mathematical models of disease transmission are being used increasingly in the
design of population-based vaccination programs. Their use is illustrated in a
review of some modeling studies that have implications for the use of measles,
mumps, and rubella vaccine. Investigations of vaccination strategy options yield
predictions for effectiveness and cost-effectiveness analyses. A quantitative
understanding of the factors affecting disease transmission enables the setting
of targets for vaccination programs and underpins disease elimination
initiatives.
PMID- 9758058
TI - Nosocomial transmission of opportunistic infections.
AB - Immunocompromised patients are at high risk for opportunistic infections.
Traditionally, these infections were thought to arise from endogenous
reactivation of previously acquired latent infections, and nosocomial
transmission therefore was deemed to be so unlikely that no special infection
control interventions were needed to prevent transmission in healthcare settings.
However, new data have challenged this view and suggest that some opportunistic
pathogens are transmissible from one immunosuppressed patient to another.
Epidemiological investigations, molecular genotyping, animal studies, and air
sampling experiments lend support to the hypothesis that reinfection with
opportunistic pathogens does occur, that airborne transmission is possible, and
that nosocomial spread is a plausible explanation for case clusters. Taken
together, these observations support the view that some opportunistic infections
are exogenous in origin and that additional epidemiological investigations are
needed to define the true risk of nosocomial spread and need for isolation.
PMID- 9758059
TI - Is Streptococcus pneumoniae a nosocomially acquired pathogen?
AB - Streptococcus pneumoniae is most prominently a major cause of community-acquired
infections of the respiratory tract, central nervous system, and bloodstream, but
there is an increasing interest in its role in the epidemiology of hospital
acquired infections. Penicillin-resistant pneumococcal strains appeared 3 decades
ago and now are present worldwide, often displaying multiple resistance due to
antibiotic selective pressure. Horizontal spread can cause either sporadic cases
or hospital outbreaks, primarily in younger children and elderly patients.
Pneumococcal transmission from one patient to another can be documented by
polymerase chain reaction or pulsed-field gel electrophoresis typing. Nosocomial
acquisition of infection, along with pediatric age, previous hospitalization, and
previous beta-lactam therapy, are the main risk factors significantly associated
with penicillin-resistant pneumococcal infections. Nosocomial acquisition also is
associated with higher mortality from pneumococcal disease. The importance of
penicillin resistance as a risk factor significantly associated with higher
mortality from pneumococcal infection is found in some studies, but not in
others. Mortality from pneumococcal pneumonia is approximately the same for human
immunodeficiency virus (HIV)-infected patients without acquired immunodeficiency
syndrome (AIDS) as for HIV-negative subjects, but it is significantly higher in
AIDS patients. Penicillin-resistant strains are involved in the vast majority of
hospital outbreaks, whether presenting as clinically manifest infection or a
simple colonization. Pneumococcal vaccination is recommended universally in order
to lower the incidence of invasive infection, although a number of problems can
limit its effectiveness.
PMID- 9758060
TI - Increasing bacteremia due to coagulase-negative staphylococci: fiction or
reality?
AB - BACKGROUND: The role of coagulase-negative staphylococci (CNS) in bacteremias
continues to be controversial. Until the 1970s, CNS were mostly recognized as
contaminants, being part of the cutaneous flora. Since then, several studies have
reported increasing incidence and severity of infections due to CNS. PURPOSE: To
review the literature concerning the epidemiology of CNS bacteremia in the United
States and Europe with reference to the multiple definitions of infection versus
contamination, considering the effect of potential biases influencing the
validity of the reported results. METHODS: Literature search of the MEDLINE
database from January 1980 to February 1998. Studies with fewer than 500 episodes
of bloodstream infections or fewer than 100 episodes of CNS bacteremia were not
included in the pooled analysis. RESULTS: (1) CNS remain the most frequent
contaminants (58%-83% of positive blood cultures); (2) the proportion of all
bloodstream infections caused by CNS is increasing (R=.51); (3) the overall
incidence of true CNS bacteremia is increasing (R=.54, P=.0014); (4) comparing
the United States to Europe, there is an increasing trend in the incidence of
nosocomial bacteremia due to CNS in the United States (R=.82, P=.0006), but no
trend is seen in European studies; (5) the mortality associated with true CNS
bacteremia varies between 4.9% and 28%. DISCUSSION: This review confirms the
increasing importance of CNS bacteremias, measured both as a proportion and as an
incidence of bloodstream infections. The contributions of several possible
explanations for the incidence increase and the difference between the United
States and Europe need further evaluation: (1) increased recognition and
awareness of CNS infections among clinicians; (2) a gradual change in the
definition of true bacteremia from an obligatory two positive blood cultures to
one positive blood culture associated with a clinical picture compatible with
infection; (3) a change in blood culture practices and techniques; (4) an
increase in the numbers of blood cultures performed, which is reported both in
the United States and in Europe; (5) a shift toward more elderly patients with
increasingly severe underlying illnesses; and (6) increasing use of intravascular
devices. CONCLUSIONS: The apparent trend of increasing CNS bacteremia seems to be
valid. Whether there is a real difference between the United States and Europe
concerning the increase of CNS bacteremia is difficult to establish due to the
large number of confounding factors. Few studies take into account the number of
blood cultures performed or the use of intravascular devices to adjust for the
observed trends. Further on-site surveillance studies are needed to investigate
the phenomenon more extensively.
PMID- 9758061
TI - Strategies for prevention of infection in short-duration neutropenia.
AB - Although infection continues to be a major cause of morbidity and mortality in
neutropenic patients, newer strategies have resulted in a shorter duration of
neutropenia. The prime risk to patients with short-duration neutropenia (defined
as neutropenia of less than 14 days) is bacterial infection, which is reduced by
the administration of prophylactic antibiotics, and possibly by the use of clean
food, sterile water, and protection against transmission of organisms from
healthcare workers' hands.
PMID- 9758062
TI - Occult nosocomial infections.
AB - Even with a good surveillance program, nosocomial infections may be not
recognized because of several reasons: absence of symptoms or prolonged
incubation period (eg, viral bloodborne infections, tuberculosis); problems with
the microbiological diagnosis, because adequate specimens may be difficult to
obtain or special methods should be used (eg, fungal infections, virus, new
agents); shorter hospital stays (eg, surgical-site infections); difficulty in
distinguishing between nosocomial and community-acquired infections (eg,
influenza); and failure to detect clinically relevant colonization (eg,
multiresistant microorganisms). Because of the important potential consequences
of occult nosocomial infections, specific surveillance programs should be
designed to address these problems.
PMID- 9758063
TI - Critical-care-unit bedside design and furnishing: impact on nosocomial
infections.
AB - Hospitals in the process of building or renovating intensive-care units (ICUs)
often establish multidisciplinary design teams. However, these teams rarely
include infection control professionals. Because nosocomial infection is common
in the ICU, design features can affect the risk of infection transmission, and
outbreaks can occur during construction, this exclusion seems short-sighted.
Infection control professionals are familiar with the relevant research, as well
as the regulations and guidelines related to ICU design and infection control
practices. Not only is their input essential to the design and construction of
safe and effective units but their presence on the design team can allow the
prospective collection of comparative data to turn the building project into a
research project.
PMID- 9758065
TI - Gullible's travels.
PMID- 9758064
TI - Outcomes and moral hazards in the medical culture of opioid phobia.
PMID- 9758066
TI - An apologia in defense of pain medicine.
PMID- 9758067
TI - An invisible history of pain: early 19th-century Britain and America.
PMID- 9758068
TI - The problem of pain in the clinicopathological method.
PMID- 9758069
TI - Perceived efficacy of pain clinics in the rehabilitation of injured workers.
AB - OBJECTIVE: To assess the perceived efficacy of pain clinics in the rehabilitation
of injured workers among four groups of professionals. DESIGN: A questionnaire
was given to 351 subjects representing four professional groups: physicians,
vocational rehabilitation counselors, staff at pain clinics, and employees of a
workers compensation program. Subjects rated the effectiveness of pain clinics in
eight specific functions, estimated the percentage of workers who return to work
after pain clinic treatment, and indicated how soon after injury a worker should
be referred to a pain clinic. RESULTS: Pain clinic staff consistently gave the
most favorable ratings and workers compensation employees the least favorable
ones. There was good agreement across professional groups regarding the need for
early referral of injured workers to pain clinics and the specific functions that
pain clinics carry out relatively well. Clinics were ranked as most effective in
reducing workers' use of opiates, and as least effective in reducing workers'
pain. Return-to-work estimates varied significantly across professional groups.
Within professional groups, subjects with high estimates gave more favorable
overall ratings to pain clinics. CONCLUSIONS: The results provide a profile of
the perceived effectiveness of pain clinics in various functions and highlight
the importance of getting accurate information about return to work rates
following pain clinic treatment. They suggest that workers are not referred to
pain clinics early enough.
PMID- 9758070
TI - Can we screen for problematic back pain? A screening questionnaire for predicting
outcome in acute and subacute back pain.
AB - OBJECTIVES: Because musculoskeletal pain is the second most frequent reason for
seeking health care, the aims of this study were to determine the value of
psychosocial variables in evaluating risk for developing chronic back pain
problems and to develop a screening methodology to identify patients likely to
have a poor prognosis. STUDY DESIGN: A prospective study was conducted on
consecutive patients with acute or subacute back pain, in which patients
completed a screening questionnaire and were then followed up for 6 months to
determine outcome. The primary outcome variable was accumulated sick leave.
METHODS: One hundred forty-two consecutive patients were asked to complete a
questionnaire designed for this study. This questionnaire contained 24 items
concerning psychosocial aspects of the problem. Six months later, patients were
contacted to complete outcome questions about accumulated sick leave. RESULTS: A
total of 97% of the patients completed both questionnaires. Although patients, on
average, improved greatly, 18% had 1-30 days and 20% had fewer than 30 days of
sick leave during the follow-up period. Five variables were found to be the
strongest predictors of sick leave outcome (fear-avoidance work beliefs,
perceived improvement, problems with work function, stress, and previous sick
leave), correctly classifying 73% of the patients as opposed to a chance rate of
33%. A total score was evaluated as a means of judging risk and found to be
strongly related to outcome. CONCLUSION: Potent psychosocial risk factors
associated with future sick absenteeism were identified. Because the total score
was related to outcome, the instrument may have use in screening patients with
acute or subacute spinal pain in clinical situations.
PMID- 9758071
TI - Analysis of peak magnitude and duration of analgesia produced by local
anesthetics injected into sympathetic ganglia of complex regional pain syndrome
patients.
AB - OBJECTIVE: Pain-relieving effects of lidocaine/bupivicaine local anesthetic (LA)
and saline (S) block of sympathetic ganglia (stellate block, 4 patients; lumbar
sympathetic block, 3 patients) were compared in 7 complex regional pain syndrome
(CRPS) patients on a double-blind crossover basis to evaluate the diagnostic and
therapeutic value of local anesthetic sympathetic blocks. DESIGN: Patients rated
their pain on a visual analog scale before and after blocks and were tested for
mechanical allodynia one-half hour after blocks. Thereafter, they rated their
pain intensity in diaries four times a day for 7 days. Each patient received two
blocks, S and LA, and served as his own control. RESULTS: Both S and LA
injections of sympathetic ganglia produced large reductions in pain intensity in
6 of 7 patients 30 minutes after block. These large reductions were accompanied
by the reversal of mechanical allodynia in both S and LA. The mean difference
between initial peak reduction in pain intensity produced by saline (68.7%) and
active local anesthetic (74.4%) did not approach statistical significance. In
striking contrast, the mean duration of pain relief was reliably longer in the
case of LA (3 days, 18 hours) as compared with S ( 19.9 hours), a difference that
occurred in all 7 patients. In a larger sample of 41 CRPS patients, signs of
sympathetic efferent blockade, including Homer' s syndrome or skin surface
temperature change, were not predictive of initial peak magnitude of pain relief
from sympathetic blockade but were predictive of duration of pain reduction.
CONCLUSION: The combination of these results provides evidence that duration of
pain relief is affected by injection of local anesthetics into sympathetic
ganglia. These results indicate that both magnitude and duration of pain
reduction should be closely monitored to provide optimal efficacy in procedures
that use local anesthetics to treat CRPS.
PMID- 9758072
TI - Homeopathic Arnica 30x is ineffective for muscle soreness after long-distance
running: a randomized, double-blind, placebo-controlled trial.
AB - OBJECTIVE: To determine whether homeopathic Arnica 30X can reduce muscle soreness
following long-distance running more than a placebo. DESIGN: Randomized, double
blind placebo-controlled trial. SETTING: Long-distance runs taking place in the
community. SUBJECTS: A total of 519 runners anticipating delayed-onset muscles
soreness after long-distance races. INTERVENTIONS: A homeopathic medicine (Arnica
30x) and an indistinguishable placebo. OUTCOME MEASURES: Subjects completed a
visual analog scale and Likert scale of muscle soreness every morning and evening
for the 5 days following their race. Race time was also recorded. The main
outcome measure was mean 2-day visual analog scores. RESULTS: Results were
obtained from 400 subjects. Groups were well matched at baseline. Mean 2-day
visual analog soreness scores for Arnica and placebo were 45.2 mm and 41.0 mm,
respectively. The 95% confidence interval was between 8.81 mm in favor of placebo
and 0.51 mm in favor of Arnica. No differences were found for Likert scores or
race time. CONCLUSION: Homeopathic Arnica 30x is ineffective for muscle soreness
following long-distance running.
PMID- 9758073
TI - Comparison of integrated group therapy and group relaxation training for
fibromyalgia.
AB - OBJECTIVE: The efficacy of an integrated, psychological treatment program was
tested in a controlled study involving 27 patients with chronic musculoskeletal
pain (fibromyalgia). DESIGN: The experimental treatment program consisted of
instruction in various self-help techniques (e.g., cognitive behavioral
strategies, relaxation, physical exercises) as well as information on chronic
pain. Control groups were instructed only in autogenic training. Measures of
pain, daily activities, general symptoms, and psychological functioning were
assessed before and after treatment, as well as at 4 months after termination of
therapy (follow-up). RESULTS: At the end of treatment, 7 patients from the
experimental group and 2 from the control group showed significant clinical
improvement in 3 of 6 parameters (NS). At follow-up, the improvement was still
present in 5 experimental cases but in none of the controls (p = 0.024).
Successful patients had been sick for a shorter period of time and were less
impaired by their condition. CONCLUSIONS: Psychological interventions in
combination with physiotherapy can be effective in treating fibromyalgia
patients, especially if applied early.
PMID- 9758074
TI - Vibration pain provocation can improve the specificity of MRI in the diagnosis of
symptomatic lumbar disc rupture.
AB - OBJECTIVE: The purpose of this study was to determine if vibration pain
provocation could be combined with magnetic resonance imaging (MRI) to increase
its specificity in identifying symptomatic disc disruption identified by
discography. DESIGN: Prospective single-blind study. SETTING: Data were collected
at a spine specialty clinic and at a diagnostic imaging center. PATIENTS: A total
of 206 discs in 78 patients (41 males, 37 females; average age, 39.7 years;
range, 18-73 years) were evaluated by MRI, spinous process vibration, and
discography. INTERVENTIONS: A hand-held prototype vibrator was applied to the
spinous process of each intervertebral disc level to be evaluated. The type of
pain provoked with vibration as well as with discography was recorded as
painless, dissimilar to clinical pain, or similar/exact reproduction of clinical
pain. The discograms and MRI scans were scored on a 0-4 scale. A system was
defined for combining the vibration results with MRI. OUTCOME MEASURES: The
results of the vibration and MRI were compared with the results of computed
tomography/discography to determine how well the results of the evaluations
agreed. RESULTS: Vibration pain provocation agreed with discographic pain
provocation in 70.9% of the discs. The specificity of MRI compared with
discographic findings was only 55.7%. However, this figure improved significantly
to 81.3% when relying on the vibration pain provocation in discs with mild or
moderate disruption. The sensitivity of the combined evaluation was 85.9% and the
accuracy 83.0%. CONCLUSIONS: A small hand-held vibrator could produce pain
provocation results similar to those obtained by discography. Results of this
noninvasive pain provocation method can improve the specificity and accuracy of
MRI in identifying symptomatic disc lesions.
PMID- 9758075
TI - Controlled trial of Japanese acupuncture for chronic myofascial neck pain:
assessment of specific and nonspecific effects of treatment.
AB - OBJECTIVE: This article examines the specific and nonspecific effects of Japanese
acupuncture on chronic myofascial neck pain in a randomized single-blind trial.
DESIGN: Forty-six patients were randomly assigned to receive relevant
acupuncture, irrelevant acupuncture, or no-acupuncture control treatment
consisting of nonsteroidal anti-inflammatory medication. The two acupuncture
groups underwent comparable light shallow needling. The irrelevant acupuncture
group received acupuncture at specific sites not relevant for cervical pain.
OUTCOME MEASURES: The study measures included the McGill Pain Questionnaire-Short
Form (SF-MPQ), the Short-Form Health Survey (SF-36), the Symptom Checklist 90
Revised (SCL-90-R), medication diary, and physiologic measures. The factors
examined as predictors of outcome pain ratings were experience with, beliefs
about, and knowledge of acupuncture before treatment; perceived efficacy,
credibility, and logic of acupuncture; perceived competence of the acupuncturist;
and painfulness of acupuncture. RESULTS: No differences were found among the
three groups at baseline, except that the relevant acupuncture group reported
having had more previous acupuncture treatments. No significant differences in
terms of perceived credibility or perceived effectiveness of treatment were found
between the two acupuncture groups. The relevant acupuncture group had
significantly greater pre-/posttreatment differences in pain than the irrelevant
acupuncture and control groups (p < .05). The nonspecific effects of confidence
in the acupuncturist, willingness to try any treatment, mood, and physiologic
effect of needling were not predictive of treatment outcome, whereas confidence
in the treatment and past experiences with acupuncture did correlate
significantly with a decrease in pain. CONCLUSIONS: Relevant acupuncture with
heat contributes to modest pain reduction in persons with myofascial neck pain.
Previous experience with and confidence in treatment help to predict benefit.
Measurement of nonspecific effects of alternative therapy is recommended in
future clinical trials.
PMID- 9758076
TI - Central nervous system abnormalities in complex regional pain syndrome (CRPS):
clinical and quantitative evidence of medullary dysfunction.
AB - OBJECTIVE: Sensory and motor abnormalities are common among patients with complex
regional pain syndrome (CRPS). The purpose of the present study was to define and
characterize these abnormalities and to develop a hypothesis regarding the area
of the central nervous system from which they derive. DESIGN: Data were acquired
from study subjects using clinical examination and quantitative assessment of
neurological function. Subjects were divided into four groups. CRPS patients were
differentiated into two groups based on the presence or absence of sensory
deficit on the face to clinical examination. The other two groups were composed
of patients with other chronic pain syndromes and normal individuals without
chronic pain or disability. Clinical and quantitative data were compared between
groups. PATIENTS: One hundred forty-five CRPS patients, 69 patients with other
pain conditions, and 26 normal individuals were studied. RESULTS: A high
incidence of trigeminal hypoesthesia was observed in CRPS patients. CRPS patients
with trigeminal hypoesthesia manifested bilateral deficits of sensory function,
with a predominant hemilateral pattern. These patients also manifested bilateral
motor weakness with a more prominent hemiparetic pattern. Both sensory and motor
deficits were greatest ipsilateral to the painful side of the body. These
features differed significantly from those of CRPS patients lacking clinical
trigeminal deficit, other pain patients, and normals. A lower cranial nerve
abnormality (sternocleidomastoid weakness) and a myelopathic feature (Hoffman's
reflex) were more common in CRPS patients with trigeminal hypoesthesia.
CONCLUSIONS: Nearly half of CRPS patients had abnormalities of spinothalamic,
trigeminothalamic, and corticospinal function that may represent dysfunction of
the medulla. One-third of the remaining CRPS patients had neuroimaging evidence
of spinal cord or brain pathology. The majority of CRPS patients in this study
have measurable abnormalities of the sensory and motor systems or neuroimaging
evidence of spinal cord or brain dysfunction.
PMID- 9758077
TI - Abolition of neurogenic pain by focal cortical ischemia.
PMID- 9758078
TI - Lamotrigine can reduce neurogenic pain associated with multiple sclerosis.
PMID- 9758079
TI - Response to "Taxonomy? Never again".
PMID- 9758080
TI - The growing importance of systolic blood pressure.
PMID- 9758081
TI - Importance of the blood pressure-heart rate relationship.
AB - In studies of the effects of salt intake on blood pressure (SBP, MBP, DBP),
influences on heart rate (HR) are usually neglected even though the longterm load
on both left ventricle (LV) and systemic arteries (SA) is better related to the
product of HR x SBP (or MBP) than to pressure alone. After all, altered salt
intakes often induce considerable volume-related changes in HR, and the heart
operates more economically at low HR and high stroke volume (SV). Thus, about 3/4
of LV metabolism is used for the build-up of systolic tension, while the cost for
SV expulsion, or for SV increases, is far lower. Moreover, low HR prolongs the
diastolic period, so important for LV coronary supply. Against this background we
have used results from studies in both rats and man, in which both BP and HR were
followed during marked changes in salt intake, to explore how this affected the
HR x SBP (or HR x MBP) product. Briefly, in ordinarily salt-resistant organisms,
whether normo- or hypertensive, salt intake increases, which in man ranged from
10-20 to 250-300 mM (in rats over 100-fold), if anything reduced the computed
longterm load (HR x SBP, or MBP) on LV and SA, as consequences of an efficient
reflex volume control. By contrast, in salt-sensitive man, HR reflex reductions
to increased salt intake were almost absent despite substantial SBP elevations,
suggesting the influence of a CNS suppression of bulbar reflex centres combined
with CNS neurohormonal interference with renal salt volume excretion, as in SHR.
PMID- 9758082
TI - The prevalence of isolated systolic hypertension in patients 60 years of age and
over attending Australian general practitioners.
AB - AIMS: To determine the prevalence of isolated systolic hypertension (ISH) in
patients 60 years of age and over attending general practitioners, and the
proportion of patients in whom blood pressure (BP) remains within the ISH range
when measured on three successive occasions and when using home BP monitoring.
METHODS: BP was measured in 38 832 patients. Patients categorized as having ISH
were reviewed after one week. Patients who had BPs in the ISH range at the second
visit were provided with a home BP monitor and attended again in one week's time
for further clinic blood pressure measurements. RESULTS: 8.6% of all patients
were classified as having ISH and 31.4% as having borderline ISH at the first
clinic visit. ISH was twice as prevalent in patients receiving antihypertensive
therapy (12.4%) than in those not on antihypertensive therapy (6.2%). Of the
patients initially categorized as having ISH, and who attended all three clinic
visits and completed the home BP monitoring, 52.3% were confirmed as having ISH,
34.0% fell into the borderline ISH range and only 7.0% had a normal BP reading at
the third clinic visit. The use of home BP monitoring produced similar results.
CONCLUSION: ISH is present on first screening in approximately 8% of elderly
Australian patients. This prevalence falls by about 50% when BP is measured on
two further occasions, with most patients subsequently falling into the
borderline ISH range. Home BP monitoring does not reduce the percentage of
patients classified as having ISH on the basis of three clinic measurements.
PMID- 9758083
TI - Influence of vascular load on plasma endothelin-1, cytokines and catecholamine
levels in essential hypertensives.
AB - In vitro studies demonstrated a relationship between ET-1 and basic Fibroblast
Growth Factor (bFGF), and of bFGF with Platelet Derived Growth Factor (PDGF). The
present study was carried out to investigate in vivo the behaviour after vascular
stress of circulating ET-1, bFGF and PDGF, and catecholamines, and their
relationship. In 12 healthy normotensives (NTs) and 15 essential hypertensives
(Ehs) venous blood samples to determine circulating ET-1, bFGF and PDGF, and
catecholamine (EPI and NE) levels were drawn before and at the third minute of a
handgrip test. Blood pressures (BP) and heart rate were automatically recorded
before starting, and at 1, 2, and 3 minutes during the test. The NTs showed, in
basal condition, lower values than the EHs of all the examined parameters; later,
the handgrip test induced significant increases in circulating levels of ET-1,
bFGF and catecholamine. In the EHs at the third minute of the exercise
significant increases in plasma ET-1 (p < 0.002), bFGF (p < 0.006), and EPI and
NE (p < 0.0005) levels were observed. Systolic and diastolic BP significantly
increased after handgrip test in NTs and EHs. Plasma ET-1 correlated with bFGF
both before (p < 0.01) and at the acme (p < 0.05) of the isometric exercise. Our
results show that in EHs plasma ET-1 and bFGF correlate each other, indicating
that in human hypertension a linkage between ET-1 and bFGF exists.
PMID- 9758084
TI - Validation of an oscillometric blood pressure measuring device: a substudy of the
HOT Study. Hypertension Optimal Treatment.
AB - The accuracy of a semi-automated oscillometric blood pressure measuring device
(Visomat OZ D2 International) was studied by simultaneous comparison with a
standard sphygmomanometer in 407 normotensive subjects and hypertensive patients.
Four pairs of measurements, at least 1 min apart, were obtained from all
patients. The oscillometric device tended to give lower measurements than the
standard device; the mean difference was -0.9 mmHg for diastolic blood pressure
and -6.4 mmHg for systolic blood pressure. The size of this difference was not
dependent on the mean blood pressure. Intra-individual standard deviations were
similar with the two techniques. The oscillometric device tended to produce
higher readings on the first measurement than on the subsequent three, whereas
the reverse was true of the standard sphygmomanometer. It is concluded that the
oscillometric device used in the HOT Study provides reliable measurements of
blood pressure. The slight difference in mean readings between the two methods is
unlikely to be of importance for the comparison of differences in treatment blood
pressure values in the HOT Study.
PMID- 9758085
TI - Clonidine suppression test revisited.
AB - BACKGROUND: The diagnosis of pheochromocytoma may be difficult because the
clinical picture is variable. OBJECTIVE: The purpose of this paper is to report
our experience and to review the published data on the diagnostic significance
and risks of the clonidine suppression test in the diagnosis of pheochromocytoma.
PATIENTS AND METHODS: 114 patients were evaluated for pheochromocytoma using the
clonidine suppression test. RESULTS: The diagnosis was established in four
patients. Overall accuracy of the test in our own series was 98% when the normal
response to clonidine was defined as total plasma catecholamines of less than 500
ng/L, or less than 70% of the baseline value. No serious complication was noted.
CONCLUSION: Our data and the published series demonstrate that the clonidine
suppression test is accurate and safe in patients with suspected
pheochromocytoma.
PMID- 9758086
TI - Reduction of cardiovascular structural changes by nifedipine GITS in essential
hypertensive patients.
AB - The aim of this study was to evaluate the effect of the calcium antagonist
Nifedipine GITS in a double-blind, randomized comparison with the diuretic
hydrochlorothiazide (HCTZ) on reduction of left ventricular (LV) mass and minimal
vascular resistance in a group of essential hypertensives with left ventricular
hypertrophy (LVH). The effects on blood pressure and on echocardiographic LV
functional parameters were also analysed. After two months of randomized
treatment with Nifedipine GITS or HCTZ, if diastolic blood pressure was > 90
mmHg, a combination of the two drugs was given and was continued for 24 weeks. M
mode, 2D-guided echocardiography was used to measure LV mass index (LVMI)
according to the "Penn convention". Minimal vascular resistance was measured in
the forearm, from arterial pressure and maximal blood flow, using a strain gauge
plethysmography. All examinations were performed before and after 8 and 24 weeks
of treatment. Changes in LVMI were analysed at 8 weeks and at 24 weeks in
patients receiving monotherapy ("according to protocol" analysis), and also at
the end of treatment in patients taking Nifedipine or HCTZ monotherapy or the
combination of the two drugs ("intention to treat" analysis). Both Nifedipine and
HCTZ significantly reduced systolic and diastolic blood pressure (p < 0.001),
without any significant difference between the two drug treatments. Heart rate
was not significantly modified by either treatment. A progressive decrease in
LVMI was observed after 8 and 24 weeks of treatment with Nifedipine monotherapy
(ANOVA, p = 0.03), while the decrease in LVMI during HCTZ treatment did not
progress further at 24 weeks (ANOVA, p = 0.49). A significant reduction of
minimal vascular resistance was observed in patients treated with Nifedipine GITS
monotherapy (ANOVA, p = 0.001), but not in the HCTZ group (ANOVA, p = 0.06).
Comparison of changes of forearm minimal vascular resistance, considering
baseline values, could demonstrate a greater effect during Nifedipine monotherapy
as compared to HCTZ monotherapy. In conclusion, in a group of hypertensive
patients with LVH, treatment for 24 weeks with Nifedipine GITS alone or in
combination with HCTZ induced a significant reduction in LVMI and of forearm
vascular structural changes, as evaluated by minimal vascular resistance. The
decrease of minimal vascular resistance was significantly greater in patients
treated with Nifedipine monotherapy, as compared to those given HCTZ.
PMID- 9758087
TI - Antihypertensive treatment with candesartan cilexetil does not affect glucose
homeostasis or serum lipid profile in patients with mild hypertension and type II
diabetes.
AB - This multicentre, randomized, controlled clinical trial assessed the effects of
candesartan cilexetil (cand.cil.), a novel angiotensin II antagonist selective
for the AT1 receptor with long-lasting antihypertensive activity, compared to
placebo on glucose homeostasis and serum lipid profile in mild hypertensives with
type II diabetes. A total of 161 men and women, 30-75 years old, with mild
hypertension (sitting diastolic blood pressure 90-100 mmHg) and type II diabetes
(HbA1c 5.5-9.0%), both measured after a 4-week placebo run-in period, were
randomized to double-blind treatment with cand.cil. 8 mg o.i.d. (n = 83) or
placebo (n = 78). Dose was increased to 16 mg o.i.d. if diastolic blood pressure
remained >90 mmHg. At randomization and after 12 weeks of treatment HbA1c
(primary effect variable), blood glucose and the serum lipid profile (including
total cholesterol, HDL and LDL cholesterol, triglycerides) were assessed. The
statistical analysis of the differences between treatments was based on changes
from randomization to the end of the study. Cand.cil. had no significant effect
on HbA1c, blood glucose and serum lipids compared to placebo. The median HbA1c
both at baseline and after 12 weeks was 7.1% in patients on cand.cil., and 7.2%
and 7.1% in patients on placebo. The 95% confidence interval for the median
difference in change between the groups was narrow (-0.25; 0.16), including zero,
which excluded any clinically important difference. The same held true for blood
glucose (-1.10; 0.20), total cholesterol (-0.40; 0.20) and the other lipid
parameters. More than 60% of the patients reached a diastolic blood pressure <90
mmHg; adverse events and withdrawals were similar in both groups. Thus, in
patients with mild hypertension and type II diabetes, cand.cil. 8-16 mg o.i.d.
for 12 weeks does not affect glucose homeostasis and serum lipids. Blood pressure
was controlled in most patients, and cand.cil. was well tolerated.
PMID- 9758088
TI - The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial of
cardiovascular events in hypertension. Rationale and design.
AB - Essential hypertension is a major Public Health issue. Although the number of
treated hypertensive patients has increased, only 25% of treated patients have
their blood pressure levels under control. The benefit of treating hypertension
has been proven, but cardiovascular morbidity and mortality rates remain high.
The ideal antihypertensive drug should not only normalize blood pressure levels,
but also reduce the associated cardiovascular morbidity and mortality rates. The
role of angiotensin II in systemic hypertension and its complications has been
recently redefined. The potent trophic effects of angiotensin II on blood vessels
and on cardiac cells have been well demonstrated, especially the role of
angiotensin II in left ventricular hypertrophy, vascular hypertrophy, endothelial
dysfunction, and congestive heart failure. Of all ongoing mortality and morbidity
trials in systemic hypertension, VALUE (Valsartan Antihypertensive Long-term Use
Evaluation) is the only one comparing an angiotensin II antagonist (valsartan)
with a third-generation calcium channel blocker (amlodipine). The main hypothesis
of the VALUE trial is that, for an equivalent decrease in blood pressure,
valsartan will be more effective than amlodipine in decreasing cardiac mortality
and morbidity. VALUE is a prospective, multinational, multicentre, double-blind,
randomized, active-controlled, 2-arm parallel group comparison with a response
dependent dose titration scheme. VALUE involves 14,400 patients in over 30
countries, who will be followed for 4 years or until 1450 patients experience a
primary endpoint. The population to be included in VALUE consists of hypertensive
men and women, aged 50 years or older, and at a relatively high risk of
sustaining a cardiovascular event. The high risk profile is defined taking into
account age, gender, and a list of cardiovascular risk factors and disease
factors. Risk factors are cigarette smoking, hypercholesterolaemia, diabetes
mellitus, uncomplicated left ventricular hypertrophy, proteinuria, and high serum
creatinine. Disease factors include documented history of myocardial infarction,
peripheral vascular disease, stroke or transient ischaemic attack, or the
presence of left ventricular hypertrophy with strain on the ECG. A unique feature
of VALUE is the assessment of the predictive power of this cardiovascular risk
factor scale in a large population of treated hypertensive patients. The trial
started on 10 September 1997.
PMID- 9758089
TI - Cardiovascular effects of dietary salts and isosorbide-5-mononitrate in
spontaneously hypertensive rats.
AB - The influence of isosorbide-5-mononitrate (IS-5-MN) on the cardiovascular effects
of high dietary salt intake (NaCl, 6.6% of dry weight of food) and that of a
potassium, magnesium and l-lysine-enriched salt alternative (Pansalt 10.5%,
producing a 6.6% content of NaCl) was studied in spontaneously hypertensive rats
in an 8-week experiment. Common salt produced a marked rise in blood pressure and
induced cardiac and renal hypertrophy, while the salt alternative, although
containing the same amount of NaCl, neither increased blood pressure nor caused
any significant cardiac hypertrophy. IS-5-MN treatment at a daily dose of
approximately 60-70 mg/kg (mixed with food) attenuated the rise in blood pressure
induced by common salt, but did not prevent the cardiac or renal hypertrophy. IS
5-MN did not offer any additional benefit to the use of the salt alternative diet
alone in treatment of high blood pressure. Mesenteric arterial responses in vitro
were examined at the end of the study. IS-5-MN treatment during the moderately
low-salt (NaCl 0.7%) control diet tended to decrease the contractile response to
noradrenaline and increase the relaxation to acetylcholine. Common salt, but not
the salt alternative, induced a 50% increase in the 24-h urinary excretion of
cyclic GMP. Both salt supplements induced an 8-9-fold increase in the excretion
of calcium, and about a 2-fold increase in the excretion of phosphorus. Common
salt also increased the excretion of magnesium by 50%. IS-5-MN treatment had no
significant effect on the excretion of the mineral elements. Our findings show
that increased intake of potassium and magnesium reduces the harmful effects of
common salt. Pressure-independent mechanisms are involved in salt-induced left
ventricular and renal hypertrophy, since they remained unaffected despite the
prevention of the salt-induced rise in blood pressure by IS-5-MN treatment.
PMID- 9758090
TI - Computer-assisted gait analysis in equine orthopaedic practice: the case for
inverse dynamic analysis.
PMID- 9758091
TI - Is it poor or loss of performance?: the science of explanation.
PMID- 9758092
TI - Post traumatic keratouveitis in horses.
AB - Traumatic keratouveitis in horses is characterised by a unilateral, aseptic,
vascularising keratitis accompanied by moderate to severe anterior uveitis. In a
series of 9 cases of post traumatic keratouveitis, topical and systemic
nonsteroidal drugs and atropine were used to control the anterior uveitis while
allowing spontaneous corneal healing. Among the 9 cases reported, 6 affected eyes
previously treated with local corticosteroids took significantly longer to
resolve when compared to 3 eyes in which corticosteroids had not been
administered. It was concluded that, in cases of equine post traumatic
keratouveitis, locally administered corticosteroids inhibit healing of damaged
corneal stroma and, by prolonging the keratitis, perpetuate the concurrent
anterior uveitis.
PMID- 9758093
TI - Stress fractures of the vertebral lamina and pelvis in Thoroughbred racehorses.
AB - Thirty-six Thoroughbred racehorses that died at California racetracks between
October 1993 and July 1994 were evaluated for stress fractures in the caudal
portion of the thoracic and lumbosacral regions of the spine and the pelvis. The
lumbosacral spine and pelvis were collected, debrided of soft tissues and
examined visually for the presence of an incomplete fracture line and focal
periosteal proliferation, characteristic of a stress fracture. Sixty-one per cent
of specimens had evidence of stress fracture in the caudal portion of the
thoracic and lumbosacral regions of the spine and the pelvis. Vertebral lamina
stress fractures were found in 50% of specimens and were positively associated
with the severity of dorsal spinous process impingement and overall severity of
articular process degenerative changes. Pelvic stress fractures affected 28 % of
specimens and occurred more frequently in older horses. Pelvic stress fractures
were positively associated with the severity of lumbar transverse process
impingement and several ilial articular surface degenerative changes. A high
prevalence of vertebral and pelvic stress fractures was noted in this sample of
Thoroughbred racehorses that died because of unrelated injuries. Vertebral and
pelvic stress fractures need to be considered in the clinical evaluation of
horses with back problems or hindlimb lameness. Undiagnosed stress fractures of
the vertebrae or pelvis could be a significant cause of poor performance and
lameness in Thoroughbred racehorses.
PMID- 9758094
TI - Net joint moments and powers in the equine forelimb during the stance phase of
the trot.
AB - The objective of this study was to provide normative data describing the net
joint moments and joint powers for the stance phase of the forelimb in trotting
horses. Kinematic and force plate data, synchronised in time and space, were
collected for the right forelimb of 6 Warmblood horses moving at a trot. The 3-D
kinematic data were collapsed onto a sagittal plane, and were combined with the
vertical and longitudinal ground reaction forces and with segment morphometric
data to calculate net joint moments in the sagittal plane across the distal
interphalangeal (coffin), metacarpophalangeal (fetlock), carpal, elbow and
shoulder joints. The joint mechanical power was calculated as the product of the
joint moment and the joint's angular velocity. Major peaks on the moment and
power curves were identified. Each joint showed consistent and repeatable
patterns in the net joint moments and joint powers. During most of stance the net
joint moment was on the caudal/palmar side of all joints except the shoulder. At
the coffin joint the power profile indicated an energy absorbing function that
peaked at 74% stance, which coincided with the maximal longitudinal propulsive
force. The fetlock joint behaved as an elastic spring; energy was absorbed in the
first half of stance as the flexor tendons and SL stored elastic energy, which
was released in the second half of stance as a result of elastic recoil. The
carpus did not appear to play an important role in energy absorption or
propulsion. Both the elbow and shoulder joints showed what appeared to be phases
of elastic energy storage and release in the middle part of the stance phase,
followed by a propulsive function at the shoulder in the later part of stance.
The fetlock, carpus and elbow showed virtually no net generation or absorption of
energy. The net energy generation at the shoulder joint was approximately equal
to the energy absorption at the coffin joint. In human subjects specific gait
pathologies produce characteristic alterations in the shape of the power profile
as well as changes in the amount of energy absorbed and generated at the joints.
In horses evaluation of net joint moments and joint powers will further our
understanding of the mechanics and energetics of lameness, and may prove to be a
useful diagnostic tool. An understanding of the function and dysfunction of
different anatomical structures will facilitate the interpretation of clinical
findings in terms of mechanical deficits.
PMID- 9758095
TI - Bone scintigraphy in the diagnosis of sacroiliac injury in twelve horses.
AB - Nuclear bone scintigraphy was used to diagnose sacroiliac injury in 12 horses
presented for nonspecific rear limb lameness. The most common history was
decreased performance and/or a mild chronic rear limb lameness which could not be
localised by routine lameness examination. The scintigraphic patterns of the 12
affected horses were compared to 5 normal horses and 10 horses with lameness not
related to the pelvic region. Subjective and quantitative evaluation of the bone
scans clearly separated the 12 affected horses from the 5 normal horses and the
10 horses with lameness from causes other than the sacroiliac joint disease. The
12 affected horses had a scintigraphic pattern of moderate to marked increased
uptake of the radiopharmaceutical within the sacroiliac joint region on the side
of lameness. In contrast, the 5 normal horses and 10 horses scanned for other
causes of lameness, had a symmetric, or only slightly asymmetric pattern of
radioisotope uptake. Although nonspecific for the type of injury, nuclear bone
scintigraphy is considered sensitive for the detection of sacroiliac injuries in
horses.
PMID- 9758096
TI - Clinical assessment of gas exchange in mature horses.
AB - There are limited methods of assessing pulmonary function in horses at rest. We
developed clinical techniques to measure gas exchange efficiency in horses and
evaluated 3 groups of horses that were 1) asymptomatic based on auscultation with
rebreathing, transtracheal aspirate cytology, and thoracic radiographs (n = 6),
2) asymptomatic at rest but symptomatic with rebreathing (n = 11) and 3)
symptomatic at rest (n = 9). Blood samples were obtained from the transverse
facial artery and jugular vein. Maximal end-tidal CO2 tension (PETCO2) was
measured by an infrared capnograph through a facemask. Alveolar O2 tension, dead
space fraction (V(D)/V(T)), and physiological shunt fraction (Q(S)/Q(T)) were
calculated using standard formulae. Arterial O2 tension in Group 1 horses (mean
+/-s.d.103+/-3 mmHg) was significantly higher than in Group 2 or Group 3 horses.
Q(S)/Q(T) in Group 1 horses (0.37+/-0.98%) was significantly lower than in Group
2 and Group 3 horses. Mean +/-s.d.V(D)/V(T) in Group 1 horses (-18.2+/-3.1) was
significantly lower than Group 3 horses but not Group 2 horses.
PMID- 9758098
TI - Dextran-70 inhibits equine platelet aggregation induced by PAF but not by other
agonists.
AB - Dextrans of mean molecular weight 70 kDa (dextran-70) have had clinical use as
anti-thrombotics in man. A major part of the anti-thrombotic action is mediated
via inhibition of platelet function. Greatorex (1975, 1977) treated
thromboembolic colic in horses with infusions of dextran-70 and reported a 90%
recovery rate, but this treatment is nonetheless rarely used. We have used an in
vitro method to examine the effect of dextran-70 on equine platelet suspensions,
in the hope that understanding the mechanism of action of dextran-70 might lead
to the development of alternative therapeutic agents. The effects of dextran-70
on equine platelets occurred immediately in vitro with an initial activation and
shape change. Subsequent assessment of aggregation revealed a dose-dependent
specific inhibition of platelet-activating factor (PAF)-induced aggregation,
significant in rate of aggregation at dextran-70 concentrations >40 g/l (P<0.05)
and in extent of aggregation at dextran-70 concentrations >50 g/l (P<0.05). Pre
incubation with 60 g/l dextran-70 significantly inhibited the rate and extent of
aggregation in response to PAF (1 nmol/l) (P<0.001 and P = 0.003, respectively)
but this was not dependent on the duration of pre-incubation (from 0 to 150 min).
No effects were seen when the agonist was adenosine 5'-diphosphate (200 nmol/l),
collagen (10 mg/l), 5-hydroxytryptamine (100 micromol/l) or U44069 (600 nmol/l)
(all P>0.1). Analysis of PAF concentration-aggregation curves after pre
incubation with 60 g/l dextran-70 indicated significant noncompetitive inhibition
by dextran-70 (P<0.001 for rate and extent of aggregation). The ability of
dextran-70 to inhibit responses of equine platelets to PAF is probably an
important component of its beneficial effect as an anti-thrombotic in colic
cases.
PMID- 9758097
TI - Maintenance of anaesthesia with sevoflurane and oxygen in mechanically-ventilated
horses subjected to exploratory laparotomy treated with intra- and post operative
anaesthetic adjuncts.
AB - Eight healthy horses premedicated with xylazine and induced with ketamine were
used to evaluate sevoflurane in oxygen for maintenance of anaesthesia during
elective exploratory laparotomy. After orotracheal intubation, horses were
hoisted, placed in dorsal recumbency on a padded surgery table, and received
sevoflurane in oxygen for maintenance of anaesthesia. The horses were allowed to
breathe spontaneously until instrumented; then, they were mechanically ventilated
to maintain the PaCO2 between 35 and 45 mmHg. Systolic (SAP), diastolic (DAP),
and mean (MAP) arterial blood pressures, heart rate (HR), ECG, respiratory rate,
an estimation of the saturation of haemoglobin with oxygen in peripheral arterial
blood (S(p)O2), nasal temperature, end-tidal CO2(ET(CO2)), end-tidal sevoflurane
(ET(SEVO)), and vaporiser concentration were recorded every 5 min post induction;
arterial blood samples were obtained soon after induction, at 30 min after
induction, and every hour thereafter until surgery was completed. Recovery data
including times from the sevoflurane vaporiser being turned off to first
movement, to sternal recumbency, and to standing, number of attempts to stand,
and recovery score (between 1 = safe, smooth and 6 = stormy, major injury to
horse) were collected. Analysis of variance was performed using physiological
data collected over 195 min of anaesthesia, the longest time period during which
all 8 horses were instrumented. Time effects (P<0.05) for HR, SAP, DAP, MAP, and
nasal temperature were identified. Heart rate peaked at 45 min and declined over
the course of the procedure. Arterial blood pressure generally decreased over
time. Body temperature decreased over time. From 15 to 195 min mean
ET(SEVO)concentration ranged from 2.0 to 3.3%, while mean vaporiser settings
ranged from 3.7 to 5.5%. Three horses received intra-operative ketamine; all
horses received dobutamine infusions; and 2 horses received intra-operative
calcium-dextrose. Total anaesthesia time was 222-316 min (mean+/-s.d.269+/-31
min). Time from turning the sevoflurane vaporiser off to first movement was mean
+/-s.d.18+/-15 min; to sternal recumbency was 54+/-22 min; to standing was 65+/
27 min; and to returning the horse to the stall in the ward was 78+/-24 min. Six
horses stood on the first attempt; 2 horses stood on the second attempt. The
median recovery score was one (1-3). In conclusion, sevoflurane provided a
stable, easily controllable anaesthetic plane during prolonged exploratory
laparotomies; horses experienced smooth, safe recoveries after maintenance of
anaesthesia with sevoflurane following routine anaesthetic induction and post
operative xyalzine administration.
PMID- 9758099
TI - An objective method for evaluating the flexibility of the back of standing
horses.
AB - The spinal movements in maximum arching, dipping and left and right lateral
flexion were measured in 10 horses without signs of back pain. A system for
motion analysis (Expert Vision System) was used to identify the position of the
markers placed on the head, the spinous processes of T5, T10, T16, L3, and on 2
of the sacral spines. By definition, the maximum of the spinal movement was set
when the T16 marker reached its maximum deviation from the start position. The
difference between start position and maximum position was presented as per cent
of the horse's height at the withers. At T16 the mean results for flexion
(arching) of the back were 5.9% (s.d.0.9), for extension (dipping) -2.4%
(s.d.0.7), for flexion to the left 4.2% (s.d.1.1), and for flexion to the right
5.3% (s.d.1.3).
PMID- 9758100
TI - Equine TIMP-1 and TIMP-2: identification, activity and cellular sources.
AB - Matrix metalloproteinases (MMPs) are the main enzymes involved in connective
tissue turnover. Regulation of MMPs is achieved by controlling production,
activation of the pro-enzymes together with the presence of inhibitors, such as,
tissue inhibitors of metalloproteinases (TIMPS). The presence of TIMPs in equine
synovial fluid was assessed by the ability of the fluid to inhibit equine MMP-9
activity using a gelatin degradation ELISA. The cellular source of the TIMPs was
determined using culture supernatants of resident articular cells (chondrocytes
and synovial fibroblasts) and invading inflammatory cells (polymorph neutrophils
[PMN] and peripheral blood monocytes [PBM]). The TIMPs were characterised further
using reverse zymography, affinity chromatography and N-terminal amino acid
sequencing. Synovial fluid was recovered from horses with articular sepsis and
aseptic joint disease (AJD) and compared with that from normal horses (n = 4).
TIMP activity was minimal in articular sepsis but significantly increased, albeit
a small increase, in AJD when compared to normal (P<0.05). Cell culture
supernatants from synovial fibroblasts, chondrocytes and PBMs contained TIMP
activity, although supernatants from PMN cell culture did not. Reverse zymography
of synovial fluid recovered from normal and AJD horses showed two protein bands,
22 and 28 kDa in size, exhibiting inhibitory activity against MMP-9. Reverse
zymography of culture supernatants of synovial fibroblasts and chondrocytes gave
similar results whereas the culture supernatants from PMNs and PBMs showed the
presence of only the 28 kDa protein. The N-terminal amino acid sequence was
obtained for the 22 kDa protein and revealed a 66% homology with human TIMP-2.
The identification of TIMPs in equine synovial fluids and cell culture
supernatants suggest that they may have a fundamental role in the homeostasis of
the normal joint and in the excess proteolysis which occurs in articular disease
in the horse.
PMID- 9758101
TI - Prevalence and characteristics of foal rejection in Arabian mares.
AB - Separate surveys of Thoroughbred, Paint, and Arabian mare owners revealed a
higher than expected rate of foal rejection in Arabian mares. A behavioural
history form was submitted by owners of foal rejecting and nonrejecting Arabian
mares, and maternal behaviour and management practices compared. Four generation
pedigrees of rejecting and nonrejecting Arabian mares were also examined. Foal
rejecting mares were more likely to avoid, threaten, squeal at, chase, bite, and
kick their foals post partum than nonrejecting mares. Nonrejecting mares were
more likely to lick, nicker and defend their foals post partum than rejecting
mares. No statistically significant relationship was found between foal rejection
and the type of breeding method (natural vs. artificial insemination), the
presence of people at birth, the presence of nearby horses at birth, or
assistance of the first nursing bout. The presence at least once of 1 of 2
related sires was statistically higher in the pedigrees of rejecting vs.
nonrejecting mares. Inherited and learned or environmental factors are likely to
affect the expression of foal rejection behaviour.
PMID- 9758103
TI - Cytology of 100 samples of abdominal fluid from 100 horses with abdominal
disease.
AB - A total of 100 samples of abdominal fluid (AF) from 100 horses with abdominal
disease were evaluated by cytology. Cytology results were subsequently correlated
with the final outcome of the disease. The horses were classified into 4 groups:
Group I, horses that were treated with conventional (nonsurgical) therapy and
recovered; Group II, horses that had surgery and survived; Group III, horses that
had surgery but died; and Group IV, horses that were subjected to euthanasia
prior to surgery. Statistical analysis showed that both nucleated cell count and
total neutrophils were significantly higher in Group III than in Group I; and
that the total mesothelial cells were significantly higher in Group III than in
Groups I and II. No significant differences were found for erythrocyte counts and
fluid total protein levels among the 4 groups. The findings suggest that
classifying AF as transudate, modified transudate and exudate, as well as grading
of inflammation as mild, moderate and severe on the basis of nucleated cell count
(NCC) and fluid total protein (AFTP) can be greatly misleading. Differential
identification of the nucleated cells was found to be far more reliable than the
NCC alone, with or without the AFTP, and rendered valuable information, which
overruled many times a diagnosis of transudate or modified transudate. Bands,
metamyelocytes, toxic changes, plasma cells, and neutrophils penetrating rafts or
fronds of mesothelial cells, supported a diagnosis of inflammation, even when the
NCC, and the AFTP (interpreted according to currently accepted values) suggested
otherwise. Several morphological features were found, including some cell types
for which little or no mention was found at all in 22 major studies of this fluid
in horses. Among these were 'reddish neutrophils', large granular lymphocytes
(LGL), plasma cells, Mott cells, blasts, and a unique hitherto undescribed
granular mesothelial cell.
PMID- 9758102
TI - Total and respirable airborne dust endotoxin concentrations in three equine
management systems.
AB - The concentrations of total and respirable airborne endotoxin in the breathing
zone of a pony in 3 different management systems, on 8 occasions, are reported.
Airborne endotoxin concentrations in all 3 systems were lower than those reported
for many other agricultural environments. However, total airborne endotoxin
concentrations in many of the conventional stables exceeded those which can
induce pulmonary inflammation and bronchial hyper-responsiveness in normal human
subjects, and exceeded those which can induce bronchoconstriction in humans with
pre-existing pulmonary inflammation. Therefore, airborne endotoxin may contribute
to the development of airway inflammation and dysfunction in conventionally
stabled horses. Potentially detrimental effects of airborne endotoxins on the
welfare and exercise performance of stabled horses can be reduced by maintaining
horses in 'low dust' stables or at pasture, since these environments had
significantly lower airborne dust and endotoxin concentrations.
PMID- 9758104
TI - Ultrasonographic confirmation of a space-occupying lesion in the brain of a
horse: choroid plexus papilloma.
PMID- 9758105
TI - Induction versus Popper: substance versus semantics.
AB - This article reviews concepts of classical logic and induction, with special
attention to the controversies surrounding Popperian claims that induction is
impossible and does not exist. I argue that some of the controversy is semantic,
and hence Popperian criticisms of induction must be translated carefully into
ordinary language to be appreciated by inductively oriented epidemiologists. With
this translation, the substance of the debate is not whether induction is
possible (it is) or exists (it does), but whether and how we should employ
probabilistic reasoning about hypotheses in epidemiological inference.
PMID- 9758106
TI - Occupational risk factors for lung cancer: a case-control study in West Germany.
AB - BACKGROUND: The aim of this study is to evaluate carcinogens and occupations
suspected to cause lung cancer and to generate new hypotheses about occupational
risks. METHODS: In a hospital-based study 1004 incident lung cancer cases and the
same number of population controls matched for region, sex and age were
interviewed between 1988 and 1993 for their smoking and occupational history.
Exposure assessment was based on 33 job-specific supplementary questionnaires.
Conditional logistic regression was used to calculate odds ratios (OR) and to
control for smoking and occupational asbestos exposure. RESULTS: Lifelong
prevalence of exposure to asbestos was 20.5% for exposure of more than 940
lifetime working hours among controls, corresponding to an OR of 1.62 (95%
confidence interval [CI] : 1.28-2.05) that was reduced to 1.45 after adjustment
for smoking (P < 5%). Statistically elevated risks after adjustment for smoking
and asbestos were seen in metal production and processing workers, transportation
workers and freight handlers, in the rubber and plastics industry, in metal
production, in engine and vehicle building, and installation. Significantly
increased OR after adjustment for smoking and asbestos that deserve further
attention were seen in plastics processing workers (OR = 3.49), and sheet and
structural metal workers (OR = 2.01 and 2.37, respectively). CONCLUSIONS: The
results of the study confirm previously described occupational risks. Because of
the possibility of controlling for occupational asbestos exposure, the study
gives clear indications for prevention and further research.
PMID- 9758107
TI - Lung and kidney cancer mortality associated with arsenic in drinking water in
Cordoba, Argentina.
AB - BACKGROUND: Studies in Taiwan have found dose-response relations between arsenic
ingestion from drinking water and cancers of the skin, bladder, lung, kidney and
liver. To investigate these associations in another population, we conducted a
study in Cordoba, Argentina, which has a well-documented history of arsenic
exposure from drinking water. METHODS: Mortality from lung, kidney, liver and
skin cancers during the period 1986-1991 in Cordoba's 26 counties was
investigated, expanding the authors' previous analysis of bladder cancer in the
province. Counties were grouped a priori into low, medium and high arsenic
exposure categories based on available data. Standardized mortality ratios (SMR)
were calculated using all of Argentina as the reference population. RESULTS: We
found increasing trends for kidney and lung cancer mortality with arsenic
exposure, with the following SMR, for men and women respectively: kidney cancer,
0.87, 1.33, 1.57 and 1.00, 1.36, 1.81; lung cancer, 0.92, 1.54, 1.77 and 1.24,
1.34, 2.16 (in all cases, P < 0.001 in trend test), similar to the previously
reported bladder cancer results (0.80, 1.28, 2.14 for men, 1.22, 1.39, 1.81 for
women). There was a small positive trend for liver cancer but mortality was
increased in all three exposure groups. Skin cancer mortality was elevated for
women only in the high exposure group, while men showed a puzzling increase in
mortality in the low exposure group. CONCLUSIONS: The results add to the evidence
that arsenic ingestion increases the risk of lung and kidney cancers. In this
study, the association between arsenic and mortality from liver and skin cancers
was not clear.
PMID- 9758108
TI - Helicobacter pylori infection and mode of transmission in a population at high
risk of stomach cancer.
AB - BACKGROUND: Helicobacter pylori (H. pylori) is a recognized cause of chronic
gastritis and peptic ulcer disease, and is strongly suspected to play a role in
the aetiology of stomach cancer but little is known about the mode of
transmission. AIM: To determine the prevalence of H. pylori infection in children
and investigate potential modes of transmission in rural China. SUBJECTS AND
SETTING: We examined 98 children aged 3-12 years and 289 adults aged 35-64 years
in a village in Linqu County, China, which has one of the highest rates of
stomach cancer in the world. METHOD: H. pylori infection was determined by 13C
urea breath test in children and by an enzyme-linked immunosorbent assay in
adults. RESULTS: Among 98 tested children, 68 (69%) were H. pylori positive, but
the prevalence rates varied as a function of age, rising from about 50% at ages 3
4 to 85% at ages 9-10 before falling to 67% at ages 11-12. Boys had a higher
infection rate than girls (77.8% versus 59.1%, P < 0.05). Among 289 adults, 195
(68%) were H. pylori positive, with a somewhat higher rate of positivity in
younger compared to older age groups. The prevalence of H. pylori infection
clustered within families. In families with at least one infected parent, 85% of
children were H. pylori positive, while in families with both parents uninfected,
only 22% of children were H. pylori positive (odds ratio [OR] = 30.4, 95% CI :
4.0-232). CONCLUSIONS: These findings demonstrate the acquisition of H. pylori
infection during early childhood in a population at high risk of stomach cancer,
in a manner consistent with a person-to-person mode of transmission between
parents and children.
PMID- 9758109
TI - A case-control study of hepatitis B and C virus infection as risk factors for
hepatocellular carcinoma in Henan, China.
AB - BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common cancers in
the world and is particularly prevalent in China. China is also a hyperendemic
area for hepatitis B virus (HBV) infection. Although a strong association between
HBV infection and HCC has been established previously, the role of hepatitis C
virus (HCV) infection and the interaction between HBV and HCV in the development
of HCC has not been adequately explored. The major objective of this study is to
determine the relationship between HBV or HCV infection and HCC by use of case
control study in Henan, China. METHOD: In all, 152 HCC patients and 115 control
patients were collected from four hospitals in Henan, China between January 1994
and October 1995. The demographic characteristics of the two groups were
comparable. In further analysis, a 1:1 pair-matched case-control study was
performed. Of 152 HCC patients, 113 were randomly selected to be pair-matched by
sex and age (+/-5 years) to controls with non-hepatic disease. All the cases and
controls were interviewed during hospitalization by two specially trained
interviewers using a standard questionnaire. All sera were tested for HBV and HCV
markers. Odds ratios (OR) and 95% CI for HCC risk factors were calculated by
logistic regression model controlling for possible confounding factors such as
sex and age. The multivariate analysis was done on the basis of the univariate
analysis. RESULTS: The results of this study indicated that the prevalence of
hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were much
higher in HCC patients (63.2% and 11.2% respectively) than in the control
patients (5.2%, 3.5%). The difference between two groups was significant (P <
0.05). Risk factor analysis revealed that both HBV and HCV infection were
important factors for HCC in Henan, China and HBV appeared to have a key role in
the development of HCC. Odds ratios of HBsAg and HBV infection were 28.82 (95%
CI: 11.18-78.78) and 31.22 (95% CI: 13.86-72.15), respectively. Moreover, the
risk of developing HCC increased significantly and showed an additive effect when
both viral markers of HBV and HCV infection were considered (OR = 42.85). Results
from the 1:1 pair-matched case-control study also showed that HBV infection was
an important risk factor for HCC, which was consistent with the results from the
group-matched case-control study. CONCLUSION: This is the first reported case
control study of HCC in Henan, China. This study provides further evidence that
chronic HBV infection is strongly associated with the development of HCC among
this population. Our results have demonstrated that HCV and HBV infection are
independent and probably additive risk factors for HCC.
PMID- 9758110
TI - An international case-control study of adult glioma and meningioma: the role of
head trauma.
AB - BACKGROUND: Increased brain tumour risk after head trauma suggested by case
reports and clinical series has been previously studied epidemiologically with
mixed results. An international multicentre case-control study investigated the
role of head trauma from injury or sports participation in adult brain tumour
risk. METHODS: In all, 1178 glioma and 330 meningioma cases were individually or
frequency matched to 2236 controls. Only exposures that occurred at least 5 years
before diagnosis and head injuries that received medical attention were
considered. RESULTS: Risk for ever having experienced a head injury was highest
for male meningiomas (odds ratio [OR] = 1.5, 95% confidence interval [CI] : 0.9
2.6) but was lower for 'serious' injuries, i.e. those causing loss of
consciousness, loss of memory or hospitalization (OR = 1.2, 95% CI: 0.6-2.3).
Among male meningiomas, latency of 15 to 24 years significantly increased risk
(OR = 5.4, 95% CI: 1.7-16.6), and risk was elevated among those who participated
in sports most correlated with head injury (OR = 1.9, 95% CI: 0.7-5.3). Odds
ratios were lower for male gliomas (OR = 1.2, 95% CI : 0.9-1.5 for any injury; OR
= 1.1, 95% CI: 0.7-1.6 for serious injuries) and in females in general.
CONCLUSIONS: Evidence for elevated brain tumour risk after head trauma was
strongest for meningiomas in men. Findings related to sports should be
interpreted cautiously due to cultural variability in our data and our lack of
complete data on physical exercise in general which appeared to be protective.
PMID- 9758111
TI - Urbanization and childhood leukaemia in Taiwan.
AB - BACKGROUND: In the 1980s socioeconomic development was dramatically rapid in the
urbanized municipalities of Taiwan due to a prospering economy. This study
addressed the question: Could differences in the incidence of childhood leukaemia
(age <15) be demonstrated between urban and rural communities in Taiwan between
1981 and 1990? METHODS: The log-linear regression model was used to assess the
effects of age, level of urbanization, and calendar year on the variation of
childhood leukaemia incidence rates between 1981 and 1990. RESULTS: Between 1981
and 1990, the overall incidence rate of childhood leukaemia increased by 20%
(rate ratio (RR) = 1.2, 95% CI: 1.0-1.5). As compared to rural areas,
metropolitan regions showed a significantly higher incidence rate during the
study period (RR = 1.3, 95% CI: 1.1-1.6). This urban-rural difference was
particularly notable among children <5 years old (RR = 1.5, 95% CI: 1.2-1.9).
Dose-response analysis further indicated that risk of childhood leukaemia was
monotonically associated with levels of urbanization. The significant gradient in
the risk of childhood leukaemia with urbanization was contributed solely by
children in the 0-4 years age group. CONCLUSIONS: We noticed a relationship
between urbanization and risk of leukaemia in children. Because of a dramatic
influx of people into metropolitan areas during the 1980s, our findings may have
provided support for the putative association between 'population mixing' or
'population density' and risk of childhood leukaemia. Whether such association
can be attributable to virus infection or other aetiologically related
leukemogens warrants further investigations.
PMID- 9758112
TI - Serum folate and chronic disease risk: findings from a cohort of United States
adults.
AB - BACKGROUND: Previous studies have suggested that folate may provide protection
against various chronic conditions. METHODS: We examined the effect of serum
folate concentration on mortality and chronic disease incidence in a nationally
representative sample of 3059 adults of the National Health and Nutrition
Examination Survey Epidemiologic Follow-up Study who were first examined from
1971 through 1975 and who were followed for about 19 years through 1992.
Proportional hazards regression was used to estimate hazard ratios for the lowest
quintile of serum folate compared with the highest quintile for selected causes
of death and disease incidence. RESULTS: The hazards ratio for all-cause
mortality was 1.18 (95% CI: 0.91-1.52); for mortality for diseases of the
circulatory system, 1.31 (95% CI: 0.82-2.12); and for cancer mortality, 0.99 (95%
CI: 0.46-2.11). The hazard ratio for incidence of diseases of the circulatory
system was 1.04 (95% CI: 0.86-1.26); and for cancer incidence, 1.00 (95% CI: 0.61
1.66). The hazards ratio for all-cause mortality was 1.26 (95% CI: 1.01-1.57) for
participants with a serum folate of <9.3 nmol/l compared with other participants.
CONCLUSIONS: Low levels of serum folate may be associated with mortality from all
causes and cardiovascular disease. However, the study lacked power to adequately
examine the association between folate and disease-specific endpoints. Additional
studies, using serum and other measures of folate nutritional status, are needed
to examine the relationship between folate nutrition and other more specifically
defined health outcomes.
PMID- 9758113
TI - Acute myocardial infarction case fatality, incidence and mortality rates in a
population registry in Gerona, Spain, 1990-1992. REGICOR Investigators.
AB - BACKGROUND: Community-based registries provide the best approach to assessing the
impact of myocardial infarction (MI) in a population. The objective of the
present study was to determine MI mortality, incidence, attack rate and 28-day
case fatality in the province of Gerona, Spain from 1990 to 1992. METHODS:
Standardized methods were used to find, register and classify MI cases in that
population (509628 inhabitants) as definite, possible and insufficient-data MI.
RESULTS: Of the 1456 cases fulfilling eligibility criteria, 850 (58.4%) were
classified as definite MI, 162 (11.1%) as fatal possible MI, 232 (15.9%) as no MI
and 160 (11.0%) as fatal insufficient data. The 1990-1992 age-standardized
incidence rates (first MI cases only) for definite and fatal possible MI were
140.8 per 100000 men and 20.4 per 100000 women, all aged 35-64 years; attack
rates (first and recurrent MI cases) were 182.9 and 24.5, and mortality rates
46.4 and 5.8, respectively. Case fatality at 28 days was 27.4% and 19.9% in men
and women, respectively, but women died later over that period. With respect to
men, the age-adjusted risk among women of dying within 28 days post-MI was 1.26
(95% confidence interval [CI]: 0.94-1.69). CONCLUSIONS: Myocardial infarction,
incidence, mortality rates and case fatality in Gerona are among the lowest in
the world. Age-adjusted case fatality within 28 days is only marginally higher in
women than in men, but fatal cases occur later within this period in women.
PMID- 9758114
TI - Regional serum cholesterol differences in Belgium: do genetically determined
cardiovascular risk factors contribute?
AB - BACKGROUND: Differences in serum lipid distribution and mortality from ischaemic
heart disease have repeatedly been reported between Belgian northerners and
southerners. We investigated whether serum lipoprotein(a) (Lp(a)) and
apolipoprotein (apo) E polymorphism were involved. METHODS: Fasting serum lipids,
apo A-I and B, and Lp(a) levels were examined in randomly selected, 20-39 year
old Belgian males and females from the north (Flanders) and the south (Wallonia)
of Belgium (N = 900). Apo E phenotype distribution was investigated in random
subsamples from either region (N = 249). RESULTS: Mean serum cholesterol, low
density lipoprotein cholesterol (LDL-c), apo B and triglyceride levels were
higher in Walloons compared to Flemings within each gender, the difference being
significant in 30-39 year old males. Average high density lipoprotein cholesterol
and apo A-I levels were significantly lower in 30-39 year old male southerners,
compared to their northern counterparts. Median Lp(a) was 67 mg/l in northerners
and 75 mg/l in southerners (NS). The apo E phenotype distribution was similar in
both regions (chi2 = 7.213; d.f. = 5; P = 0.2053), whereas the average effects of
the apo E alleles differed between the regions. In southerners the epsilon4
effect upon adjusted apo B and LDL-c levels was approximately+12% and the
epsilon2 effect was approximately-15%; in northerners the epsilon4 and epsilon2
effects were approximately+5% and approximately-25%, respectively. The apo E
polymorphism did not affect serum Lp(a) levels. CONCLUSIONS: Regional cholesterol
differences between Flemings and Walloons cannot be explained by differences in
serum Lp(a) or apo E phenotype distribution. The less favourable epsilon2 and
epsilon4 effects in southerners compared to northerners reflect modulation of the
apo E gene by particular environments.
PMID- 9758115
TI - Secular trends in blood pressure levels in Denmark 1964-1991.
AB - BACKGROUND: Hypertension is an essential risk factor for development of
cardiovascular diseases. Prospective studies show a reduction in risk of
myocardial infarction with reduction of blood pressure. In Denmark there was a
decrease in ischaemic heart disease mortality during the period (1968-1992) with
around 34% in 30-65 year old men and 30% in women. OBJECTIVE: To assess the
changes in casual blood pressure between 1964 and 1991 in seven cross-sectional
population studies. SETTING: Centre of Preventive Medicine, University of
Copenhagen, DK-2600 Glostrup. POPULATION: 10359 subjects, equal numbers of men
and women, age exactly 30, 40, 50 and 60 years drawn as random samples from a
background population of 300000 inhabitants and surveyed in 1964-1974 and five
cross-sectional studies 1976, 1978, 1982-1984, 1986-1987 and 1991. METHODS: Blood
pressure was measured according to WHO criteria by one technician in each survey.
Alcohol consumption and physical activity were measured by a self-administered
questionnaire. The weight and height were measured by standardized methods. Data
on mortality from ischaemic heart disease were obtained from death certificates
recorded by the National Board of Health. RESULTS: Blood pressure increased with
increasing age in both genders and was significantly higher in men than in women.
Median blood pressure in 50 year old men in 1964 was 135/85 mmHg and in 1991 it
was 123/79, whereas in women in 1964 it was 140/85, against 119/74 in 1991. The
prevalence of hypertensives among 30 and 40 year olds declined throughout the
period. The performance of blood pressure measurements, technical variation,
examination programme, seasonal variation and inter-observer variation were
potential bias sources and influenced blood pressure levels, but cannot be shown
to be responsible for the declining trend in blood pressure and hypertension.
Women became a little more physical active in leisure time and men less active.
Women consumed less alcohol than men, but the amounts slightly increased by the
end of the period. Body mass index >25 was seen less frequently in women than in
men and this increased in men over the period. Sale of antihypertensive drugs
increased in Denmark over the 1964-1991 period. There seems to be good agreement
between the changes in blood pressure in the population and the decline in
mortality from stroke and coronary heart disease in Denmark, which is influenced
by other risk factors as well. CONCLUSION: Blood pressure distributions have
shifted towards lower values in 1964-1991. Prevalence of hypertension declined up
to 1983. Risk factor changes as well as treatment for hypertension contribute to
this.
PMID- 9758116
TI - Unemployment, sociodemographic background and consumption of alcohol before and
during the economic recession of the 1990s in Finland.
AB - BACKGROUND: Some studies suggest that people's alcohol consumption increases
during unemployment whereas others suggest the opposite. All studies, however,
deal with situations marked by relatively low national unemployment rates. We
studied alcohol use among individuals in relation to unemployment, education,
marital status and sex during times of both low and high unemployment in Finland.
METHODS: A group of 44391 respondents, aged 18-64 years, from nationally
representative, consecutive annual samples of 5000 people from 1982 to 1995 was
utilized. Overall response rate for men was 77% and for women 80%. RESULTS:
Univariate analyses indicated that unemployment was associated with the amount of
reported alcohol use. However, when logistic regression was used to analyse
interactions between alcohol consumption, unemployment, education and marital
status, the picture changed. During a low unemployment period (e.g. 1982-1990),
being unemployed was not associated with the upper consumption level of alcohol
use (defined as > or = 8 drinks/week for men, > or = 5 for women); nor was it
during a high unemployment period (1991-1995), except among single people. During
a high unemployment period poorly educated, single, unemployed men (odds ratio
[OR] = 1.6, 95% confidence interval [CI] : 1.1-2.4), showed a significantly
higher risk of upper level of alcohol consumption than otherwise similar but
employed men (OR = 0.8, 95% CI: 0.6-1.0). The reference group consisted of highly
educated, married, employed men who did not exceed the upper drinking limit.
Similarly, the risk of upper consumption level drinking was significantly higher
among highly educated, unemployed single women (OR = 2.4, 95% CI: 1.388-4.3) than
among otherwise similar but employed women (OR = 1.1, 95% CI: 1.0-1.386).
CONCLUSION: Thus, unemployment was weakly but significantly related to the upper
consumption level of alcohol use among single people during the recession but not
in the preceding period of economic growth.
PMID- 9758117
TI - Prevalence of respiratory symptoms: marked differences within a small
geographical area.
AB - BACKGROUND: Geographical differences in prevalence of respiratory symptoms have
been reported between countries in the EC Respiratory Health Survey (ECRHS). The
differences between two neighbouring centres in the Antwerp area were surprising.
We therefore extended the screening phase of this study to four other areas with
different features in this region. METHODS: Methods and questionnaires of the
first phase of the ECRHS were used to estimate prevalence rates of respiratory
symptoms in all areas. Information on some major personal and environmental risk
factors was also obtained. RESULTS: Higher prevalence rates of both respiratory
symptoms and personal risk factors were recorded in Urban Antwerp, Berendrecht
Zandvliet (harbour area) and Zwijndrecht (industrial area) than in Suburban
Antwerp, Essen and Kasterlee (both rural). Neither personal nor environmental
risk factors could provide satisfactory explanations for the area differences in
symptoms. CONCLUSIONS: These large differences between groups of subjects living
within a small geographical area prove that estimations of prevalence rates of a
whole country based on measurements of prevalence in one specific area should be
interpreted very cautiously. Epidemiological research within small geographical
areas may thus still prove as informative as comparisons between countries for
elucidating causes for different asthma prevalence.
PMID- 9758118
TI - Sixteen-year coronary mortality in black and white men with diabetes screened for
the Multiple Risk Factor Intervention Trial (MRFIT).
AB - BACKGROUND: Risk of coronary heart disease (CHD) mortality associated with
diabetes is high and it is unclear to what extent the high mortality is due to
modifiable risk factors. To explore this, mortality and predictors of CHD death
are compared in a large cohort of black and white men with diabetes. METHODS: In
all, 610 black and 3997 white men who reported taking medication for diabetes and
had no history of hospitalization for heart attack were screened by 22 centres
for the Multiple Risk Factor Intervention Trial (MRFIT). At screening major risk
factors for CHD were determined. Participants have been followed for an average
of 16 years for vital status. Cause-specific mortality and predictors of CHD are
compared for blacks and whites using proportional hazards regression. RESULTS:
Serum cholesterol and systolic blood pressure levels were similar in blacks and
whites with diabetes, while diastolic blood pressure and percentage of smokers
were higher in blacks (89 versus 86 mmHg and 47% versus 34%) and median income
was lower. Coronary heart disease was the leading cause of death, accounting for
31% (68/221) and 44% (564/1293) of deaths among blacks and whites, respectively.
Adjusted relative risks of CHD death and all cause mortality for blacks compared
to whites were 0.71 (95% CI: 0.53-0.95) and 0.94 (95% CI: 0.75-1.11). Differences
in reporting cause of death probably account for some of the black/white
difference in CHD. High serum cholesterol, high blood pressure, and smoking
increased risk of CHD death similarly in blacks and whites. CONCLUSIONS: Serum
cholesterol, blood pressure, and smoking are major influences on CHD mortality
risk in both white and black men with diabetes. High prevalence of these factors
indicates substantial potential for CHD prevention in both ethnic groups.
PMID- 9758119
TI - Risk of preterm delivery, low birthweight and growth retardation following
spontaneous abortion: a registry-based study in Denmark.
AB - BACKGROUND: Some studies have found an association between spontaneous abortion
and adverse birth outcome in the subsequent pregnancy, but results are
conflicting, maybe due to lack of confounder control. METHODS: Using population
based registries we identified a cohort of 45 449 women having a livebirth
preceded by a spontaneous abortion ('abortion cohort'), and a random sample of
9752 women with two consecutive livebirths ('reference cohort'). We examined the
risk of preterm (<37 weeks gestation) and very preterm delivery (<34 weeks), low
birthweight and growth retardation in both births in the reference cohort
compared with births following an abortion, controlling for social factors and
interpregnancy interval. RESULTS: Compared to second births in the reference
cohort, the abortion cohort had higher risks for preterm (odds ratio [OR] = 1.74,
95% CI: 1.5-2.0) and very preterm delivery (OR = 2.17, 95% CI : 1.7-2.7), low
birthweight (OR = 1.76, 95% CI: 1.5-2.1), and growth retardation (OR = 1.50, 95%
CI: 1.4-1.6). In the reference cohort 3.9% of the pregnancies ended as preterm
deliveries, 1 % as very preterm, 3.3% as low birthweight, and 8.1% as growth
retarded. Women with two or more previous abortions had a higher risk for preterm
and very preterm delivery. When first liveborns of women in the reference cohort
were compared with first liveborns in the abortion cohort, only deliveries before
34 and 37 weeks' gestation were associated with previous abortion. CONCLUSIONS:
Spontaneous abortion is associated with preterm delivery (both <34 and <37 weeks)
in the subsequent pregnancy. Women who become pregnant following an abortion
should receive special attention in the antenatal clinics.
PMID- 9758120
TI - Maternal cotinine level during pregnancy and birthweight for gestational age.
AB - BACKGROUND: Recent studies have found that cotinine is a better predictor of
birthweight than the number of cigarettes smoked in pregnancy. In this paper we
test this hypothesis and use cotinine to explore the effect of environmental
tobacco smoke (ETS) on birthweight. METHODS: In all, 1254 white women were
interviewed at booking, 28 and 36 weeks about the number and brand of cigarette
smoked. Cotinine was assayed from blood samples taken on the day of interview.
The outcome was birthweight for gestational age. RESULTS: There was good
agreement between self-reported smoker/non-smoker status and maternal cotinine
with 1.3% women mis-reported as non-smokers at booking, 0.6% and 1.8% mis
reported at 28 and 36 weeks respectively. Among smokers, cotinine was more
closely related to birthweight than the number of cigarettes smoked at all three
time points (r = -0.25 versus r = -0.16 at booking). A reduction in cotinine
between booking and 28 weeks was associated with increased birthweight but the
effect was not statistically significant. Among non-smokers the association
between birthweight and cotinine was not statistically significant after
adjusting for maternal height, parity, sex and gestational age. Difference in
mean birthweight between non-smokers in the lower and upper quintiles of cotinine
was 0.2% (95% CI: -2.4, 2.8). Pooling the results of 10 studies plus our own gave
an estimated difference in mean birthweight between women unexposed and exposed
to passive smoke of 31 g (95% CI: 19, 44). CONCLUSIONS: Cotinine is a better
predictor of birthweight than the reported number of cigarettes smoked. If
biochemical analysis is impossible, then self-reported smoking habit should be
obtained prospectively using a structured approach. Any effect on birthweight of
maternal passive smoking during pregnancy is small compared with the effects of
maternal active smoking.
PMID- 9758121
TI - Is there a consequence for fetal growth of having an unlike-sexed cohabitant in
utero?
AB - BACKGROUND: There is evidence to suggest a masculinizing effect on female
intrauterine development in unlike-sexed twins. The purpose of the present report
was to examine the possible effects of male presence on fetal growth in females
by comparing mean birthweights in members from dizygotic unlike-sexed (DZU) pairs
with those from dizygotic like-sexed (DZL) pairs. METHODS: The sample consisted
of 1087 DZU and 1089 DZL twin pairs from the New Norwegian Twin Panel, which was
established by identifying all twin births from 1967 to 1974 through the
population-based Medical Birth Registry. RESULTS: The mean birthweight of females
from DZU pairs was 2684+/-15 g (+/-SEM), as opposed to 2647+/-19 g in females
from DZL pairs (P = 0.06). For males, the mean birthweight was 2812+/-16 g in DZU
pairs and 2805+/-20 g in DZL pairs (P= 0.78). CONCLUSION: We found a tendency for
the birthweight in females to be influenced by the presence of a male co-twin.
This observation may have a biological significance and should lead to a close
follow-up of DZU and DZL females with respect to hormone-sensitive disorders and
reproductive ability.
PMID- 9758122
TI - A comparison of three verbal autopsy methods to ascertain levels and causes of
maternal deaths in Matlab, Bangladesh.
AB - BACKGROUND: Verbal autopsies have been widely used to determine the levels and
causes of maternal death but few studies have assessed the reliability of various
methods. METHODS: We compared the levels and causes of maternal mortality in
three data sources from Matlab, Bangladesh: (1) maternal deaths identified
through a unique demographic surveillance system (DSS); (2) maternal deaths
identified as a result of a previous detailed investigation into the levels and
causes of maternal mortality; and (3) maternal deaths identified in the current
special study. All studies used lay reporting, but differed in terms of the
nature of the study, the sex of the interviewer, the format of the questionnaire
and the procedure to derive the diagnosis. RESULTS: There were substantial
disagreements between the routine reporting and the special studies. The DSS
identified 67.2% of all deaths occurring during pregnancy or within 42 days
postpartum (82.3% of direct obstetric deaths, 70.0% of deaths due to induced
abortions and 42.4% of indirect obstetric deaths). Extending the definition of
maternal deaths to 90 days postpartum increased the numbers of maternal deaths
between 1987 and 1993 from 174 to 196. The two special studies also disagreed in
the ascertainment of the causes of maternal deaths and yielded different cause of
death distributions; the proportion of direct obstetric deaths (excluding
abortion) was 50.4% in the current system compared to 44.5% previously (P =
0.001). CONCLUSIONS: This study confirms the known difficulties in the
ascertainment of the levels and causes of maternal mortality. The large
disparities in the levels and causes of maternal mortality using three different
methods of lay reporting in a population with an almost complete vital
registration system add to the growing concern about the inaccuracies in the
measurement of maternal mortality.
PMID- 9758123
TI - Dental amalgam and multiple sclerosis: a case-control study in Montreal, Canada.
AB - BACKGROUND: The aetiology of multiple sclerosis (MS) remains poorly understood.
Dental amalgams containing mercury have recently been suggested as a possible
risk factor for MS. METHODS: In a case-control study conducted between 1991 and
1994, we interviewed a total of 143 MS patients and 128 controls, to obtain
information on socio-demographic characteristics and the number of dental
amalgams and the time since installation based on dentists' records. RESULTS:
Neither the number nor the duration of exposure to amalgams supported an
increased risk of MS. After adjustment for age, sex, smoking, and education those
who had more than 15 fillings had an odds ratio (OR) of 2.57 (95% CI: 0.78-8.54)
compared to those who had none; for individuals whose first amalgam was inserted
more than 15 years prior to the study, we found an OR of 1.34 (95% CI: 0.38
4.72). CONCLUSIONS: Although a suggestive elevated risk was found for those
individuals with a large number of dental amalgams, and for a long period of
time, the difference between cases and controls was not statistically
significant.
PMID- 9758124
TI - Comparison of key informant and survey methods for ascertainment of childhood
epilepsy in West Bengal, India.
AB - BACKGROUND: This study aimed to compare efficacy and cost of key informants and
survey for ascertainment of childhood epilepsy within a treatment context in
rural India. METHODS: The study was set in a non-governmental, community
programme for the functional and socioeconomic rehabilitation of children with
disabilities in rural West Bengal, India. Ascertainment was by two methods: house
to-house survey of 15000 households and also by 430 key informants including
village leaders, health workers and 670 schoolchildren. Methods were compared for
positive predictive value, and sensitivity by capture-recapture technique. Ninety
four children were enrolled into treatment. Predictors of treatment success were
determined by multiple logistic regression analysis, giving adjusted odds ratios
for remission. The costs of identifying one case and one treatment success were
measured by costing personnel, materials and overheads. RESULTS: The survey was
four times as sensitive as key informants although the positive predictive values
were similar (36%, 40%). The survey had an absolute sensitivity of only 59%.
Identification by key informants strongly predicted successful treatment outcome
(odds ratio [OR] = 4.74, 95% confidence interval [CI] : 1.19-18.85). The cost of
finding one case was US$11 and US$14, and of finding one successful treatment
outcome US$35 and US$67 for informants and survey respectively. Key informants
were essential in attaining longer term programme objectives. CONCLUSIONS: In the
context of a treatment programme, key informants were the more cost-effective
method, but community involvement was traded against low sensitivity in the short
term. Overall ascertainment costs were significant in the context of primary
health care in India.
PMID- 9758125
TI - Bangungut in Manila: sudden and unexplained death in sleep of adult Filipinos.
AB - BACKGROUND: Sudden and unexplained death in sleep (SUDS) is a leading cause of
death of young men in several Asian populations, but the history and epidemiology
of SUDS are not well known. METHODS: Autopsy records were reviewed in Manila in a
study of the classification of SUDS. Death certificates filed in Manila during
1948-1982 were then reviewed in a study of SUDS incidence. A nested case-control
study of death certificates examined birthplace as an indicator of SUDS risk.
RESULTS: The classification of SUDS cases in Manila during 1948-1982 (N = 722)
evolved from the folk term, bangungut ('to rise and moan during sleep'), to
various descriptions of post-mortem artefacts. The characteristics of victims in
each of the groups were similar: 96% male, mean age 33 years, and modal time of
death 3:00 a.m. The deaths were seasonal, peaking in December-January. SUDS
victims were more likely than deceased controls to have been born outside of the
Manila region (relative odds = 2.11; 95% CI: 1.59-2.78). The SUDS rate for men
aged 25-44 years increased from 10.8 to 26.3 per 100000 person-years from 1948 to
1982. CONCLUSION: The death certificate classification of SUDS in Manila has
changed considerably, obscuring an increase in incidence. SUDS appears to be a
regional phenomenon in Southeast Asia and environmental causes are likely because
the deaths are seasonal, increased over the timespan studied, and are more common
among migrants to Manila than among those born there.
PMID- 9758126
TI - Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS)
mortality in industrialized nations, 1987-1991.
AB - OBJECTIVE: To compare patterns of human immunodeficiency virus (HIV)/acquired
immunodeficiency syndrome (AIDS) mortality in 11 selected industrialized
countries with highly developed death registration systems and a broad range of
cumulative AIDS incidence rates. METHODS: Data on HIV/AIDS mortality were
obtained from the World Health Organization (WHO) and Statistics Canada for the
years 1987-1991. We obtained data for Australia, Canada, Denmark, France, the
former Federal Republic of Germany, Italy, the Netherlands, New Zealand, Spain,
Switzerland, and the US, stratified by sex and 5-year age groups. Population
figures were obtained from national censal, post-censal or interpolated annual
estimates compiled by WHO and from Statistics Canada. RESULTS: A total of 141534
deaths were attributed to HIV/AIDS (126224 in men and 15310 in women) in the 11
countries from 1987 to 1991. The majority of deaths (73.7%) occurred in the US.
Other countries contributing substantially to the number of deaths were France
(7.1%), Italy (4.9%), Spain (4.9%), former West Germany (3.5%), and Canada
(3.0%). Age-specific death rates for men aged 25-44 years in 1991 were highest in
the USA at 47.1 per 100000 population and highest for women in Switzerland at 7.7
per 100000 population. Potential years of life lost (PYLL) before age 75 years
were highest for males in the US (2388 per 100000 population) and for females in
Switzerland (373 per 100000 population). The lowest rates were in New Zealand
(339 per 100000 population in men and 6.5 per 100000 population in women).
CONCLUSIONS: This historical demographic analysis indicates that mortality
resulting from HIV infection and AIDS among men and women varies considerable by
country. Rates of death were highest in the US and lowest in Australia, the
Netherlands, and New Zealand.
PMID- 9758127
TI - Socioeconomic geographical links to human immunodeficiency virus seroprevalence
among childbearing women in Montreal, 1989-1993.
AB - BACKGROUND: To describe the socioeconomic profiles of geographical areas on
Montreal Island in which human immunodeficiency virus (HIV) seropositive women
delivering live births between 1989 and 1993 reside. METHODS: Leftover dried
blood spot filter paper specimens collected from newborns were irretrievably
unlinked from identifying information prior to testing. Seroprevalence estimates
were calculated based on Western blot confirmed positive samples. Using data from
the Canadian census, Revenue Canada, and provincial birth records, the
socioeconomic characteristics of postal zones in which seropositive mothers
reside were described. RESULTS: Montreal Island had an overall 5-year HIV
seroprevalence rate estimate of 16.6 (95% CI: 14.1-19.3) per 10000 childbearing
women. Areas in which at least one seropositive woman gave birth had lower mean
infant birthweights and higher percentages of single mothers and single-parent
families. The HIV-positive neonatal blood specimens were more likely to originate
from areas where a higher proportion of residents reported less education,
greater unemployment, and lower income. CONCLUSIONS: Higher HIV infection rates
were found among childbearing women from lower socioeconomic areas of Montreal.
Increased understanding of the relationship between socioeconomic status and HIV
acquisition and transmission is required to inform the development of targeted
HIV prevention programmes.
PMID- 9758129
TI - CD4+ lymphocytes and tuberculin skin test as survival predictors in pulmonary
tuberculosis HIV-infected patients.
AB - BACKGROUND: We analyse whether the tuberculin skin test is a good survival marker
in a cohort of pulmonary tuberculosis patients with HIV infection (PTB/HIV). In
all, 494 PTB/HIV patients were enrolled in Barcelona (Spain) between January 1992
and December 1994 in the Tuberculosis Program of Barcelona. The main data problem
was the large proportion of missing values in the covariates percentage of T CD4+
lymphocytes and the tuberculin test results: only 157 patients (31.8%) had both
covariates recorded. METHODS: Patients were dichotomized into two groups
according to their level of immunosuppression (< or = 14 and >14% T CD4+ cells).
First, we carried out the semiparametric and parametric complete case analysis.
After this, we analysed the data assuming a missing at random non-response
pattern. We developed a bootstrap approach where missing data in the markers are
imputed via a two-way linear model. Using Weibull regression estimation, we used
a multiple imputation scheme to estimate the parameters of interest. RESULTS: We
found significative differences for the most immunosuppressed group when
comparing positive tuberculin patients with those who were tuberculin negative.
From a complete case approach and through a multivariate Cox analysis, we
obtained a significant relative hazard of 0.3657 (95% CI: 0.13-1.02; P = 0.054).
When a Weibull model was fitted, we estimated a constant relative percentile
value of pR = 4.1329 (95% CI: 0.97-17.59). From a missing data approach, we
obtain a higher constant relative percentile 5.48 (P = 0.079). CONCLUSIONS: The
imputation method allows us to assess the protective character of positivity for
the tuberculin test for the lowest CD4+ level. These findings strongly suggest
the value of the tuberculin skin test as a qualitative measure of the
immunological response and its interest for developing countries where specific
laboratory tests are not affordable.
PMID- 9758128
TI - Causes of death in a rural, population-based human immunodeficiency virus type 1
(HIV-1) natural history cohort in Uganda.
AB - BACKGROUND: While human immunodeficiency virus (HIV)-related causes of death have
been well documented in developed countries, in Africa data are scanty and mainly
based on autopsy studies from city hospitals which are highly selective and may
not represent causes of HIV-associated deaths in the general population. This
study, from a rural population, describes the causes of death in HIV-positive
people and their HIV-negative controls. METHODS: A natural history cohort
comprising HIV-1 infected participants and HIV-negative controls was established
in rural Uganda in 1990. Causes of death were determined by reviewing the
premorbid clinical and laboratory findings and from information obtained from
relatives. Blindness to the deceased's HIV serostatus was maintained throughout.
RESULTS: In all, 78 deaths occurred over a 6-year period: 63 deaths occurred in
the HIV-positive cases (53 prevalent and 10 incident cases) and 15 deaths in the
HIV-negative controls. Of the prevalent cases, 56%, and 9% the incident cases
enrolled died, compared with 7% of the HIV-negative controls. Of the 55 HIV
positive cases with sufficient data to establish cause of death, 52 (95%) were
assessed as having HIV-associated deaths and 48 (87%) died in WHO stage 4 (AIDS).
The main causes of death were wasting syndrome (31%), chronic diarrhoea (22%),
cryptococcal meningitis (13%) and chest infection (11%). CONCLUSIONS: Our results
represent an unbiased selection of deaths in a rural area. The HIV-positive cases
have high death rates and die of HIV-related pathologies. The main causes of
death reflect the WHO clinical case definition of AIDS. Cryptococcal meningitis
is also a common cause of death in this population.
PMID- 9758130
TI - Delayed-type hypersensitivity to Mycobacterium leprae soluble antigens as a test
for infection with the leprosy bacillus.
AB - BACKGROUND: Mycobacterium leprae (M. leprae) soluble antigen (MLSA) reagents have
been developed with the aim of finding a reagent, comparable to tuberculin, which
could identify individuals infected with the leprosy bacillus. They have yet to
be evaluated fully in human populations. METHODS: More than 15000 individuals
living in a leprosy endemic area of northern Malawi were skin tested with one of
five batches of MLSA prepared using two different protocols. The main difference
in preparation was the introduction of a high G centrifugation step in the
preparation of the last three ('second-generation') batches. RESULTS: The
prevalence of skin-test positivity (delayed-type hypersensitivity (DTH)) and
association with the presence of a BCG scar were greater for first (batches A6,
A22) than second (batches AB53, CD5, CD19) generation reagents. The association
of positivity with M. leprae infection was investigated by comparing results
among known (household) contacts of leprosy cases, and among newly diagnosed
leprosy patients with those in the general population. While positivity to 'first
generation' antigens appeared to be associated with M. leprae infection,
positivity to later antigens was unrelated either to exposure to leprosy cases or
presence of leprosy disease. There were geographical differences in the
prevalence of DTH to the various batches, probably reflecting exposure to various
mycobacteria in the environment. CONCLUSIONS: Our results suggest that the
'second-generation' batches have lost antigens that can detect M. leprae
infections, but that they retain one or more antigens which are shared between M.
leprae and environmental mycobacteria. Natural exposure to these both sensitizes
individuals and provides natural protection against M. leprae infection or
disease. Identification of antigens present in these groups of skin test reagents
may assist in production of improved skin test reagents.
PMID- 9758131
TI - Estimates of the severity of illnesses associated with bathing in marine
recreational waters contaminated with domestic sewage.
AB - BACKGROUND: During the summers of 1989-1992 we conducted four randomized
intervention trials at four separate UK bathing locations judged of acceptable
quality under current USEPA and EU criteria. The results showed bathers to be at
increased risk of gastroenteritis, acute febrile respiratory illness (ICD-9 461
466, 480), ear and eye infections relative to non-bathers. The public health
significance of these findings has been questioned based upon the unproven
assumption that these illnesses are minor in nature and thus of questionable
public health significance. METHODS: The severity of these illnesses or ailments
in terms of duration of illness, percentage of participants seeking medical
treatment, and number of days of lost normal daily activity among study
participants reporting specific illnesses or ailments were assessed. In addition
the attributable proportion of illness among the exposed (bathers) was calculated
for each illness or ailment. RESULTS: Average duration of illness ranged from
approximately 4 days to approximately 8 days depending on the specific illness
reported. The percentage of study participants seeking medical treatment ranged
from 4.2% to 22.2% while the percentage reporting the loss of at least one day of
normal daily activity ranged from 7.0% to 25.9% depending on the illness
reported. The overall percentage of each illness that can be directly
attributable to exposure to marine waters contaminated with domestic sewage
ranged from a low of 34.5% for gastroenteritis to a high of 65.8% for ear
infections. CONCLUSIONS: To our knowledge, this is the first study to assess and
report the severity of illnesses associated with bathing in recreational waters
contaminated with domestic sewage. Illness associated with bathing in marine
waters contaminated with domestic sewage can no longer be viewed as minor, and
indeed can have a substantial impact on the public health.
PMID- 9758132
TI - A methodological note on the selection of friends as controls.
AB - A number of issues inherent in the selection of friends as controls in case
control studies are illustrated in the light of a recent dietary study, based on
hospital and friend controls. Preselection of certain characteristics of the
controls by the interviewee is almost unavoidable. The choice of controls to be
used in a case-control study must reflect the nature and type of hypothesis which
is being tested. Advantages and drawbacks of potential control groups must be
weighted against each other.
PMID- 9758134
TI - Collagen fibre arrangement in the tibial plateau articular cartilage of man and
other mammalian species.
AB - Experimental animal models are frequently used to study articular cartilage, but
the relevance to man remains problematic. In this study animal models were
compared by examination of the collagen fibre arrangement in the medial tibial
plateau of human, cow, pig, dog, sheep, rabbit and rat specimens. 24 cartilage
samples from each species were prepared and maximum cartilage thickness in the
central tibial plateau measured. Samples were fixed, dehydrated, freeze-fractured
and imaged by scanning electron microscopy (SEM). At low magnification, 2
different arrangements of collagen fibres were observed: leaf-like (human, pig,
dog) and columnar (cow, sheep, rabbit, rat). The porcine collagen structure was
the most similar to that of man. This arrangement was consistent from the radial
to the upper zones. Under higher magnification at the surface of the leaves, the
collagen was more randomly oriented, whereas the columns consisted of parallel
collagen fibrils. The maximum thickness of cartilage did not correlate with the
type of collagen arrangement but was correlated with the body weight of the
species (r = 0.785). When using animal models for investigating human articular
cartilage function or pathology, the differences in arrangement of collagen
fibres in tibial plateau cartilage between laboratory animals should be
considered especially if morphological evaluation is planned.
PMID- 9758135
TI - Morphological and quantitative studies in the otic region of the neural tube in
chick embryos suggest a neuroectodermal origin for the otic placode.
AB - Careful histological observation of the development of the anlage of the inner
ear in chicken embryos led us to question the traditional view of otic placode
(OP) formation. First, morphological studies in the cephalic region carried out
on stages preceding the appearance of the placodal epithelium revealed that the
medial placodal cells are continuous temporally and spatially with cells
belonging to the neural fold (NF). Second, both the formation of the basal lamina
between the dorsal region of the neural tube (NT) and ectoderm and the pattern of
formation of the neural crest present distinctive characteristics between otic
levels and regions located anteriorly and posteriorly. Third, numerical
comparisons of parameters for the NT and the OP between different levels of the
rhombencephalon allowed us to assign a differential behaviour in the growth
pattern of the otic region. These results indicated that the medial part of the
OP is not derived from already independent ectoderm that increases in thickness
under the influence of the NT (as previously accepted) but that it develops
directly from the NFs. Although we do not exclude other possibilities, we propose
that at least a proportion of the OP cells originate directly from cells
committed to be neural crest. After this incorporation, basal laminal formation
would delimit the NT from the OP without transition of the otic cells to
ectoderm. This hypothesis would imply that part of the otic cells originate
directly from neuroepithelial cells having a neuroectodermal (rather than the
previously established ectodermal) origin.
PMID- 9758133
TI - The role of laminins in basement membrane function.
AB - Laminins are a family of multifunctional macromolecules, ubiquitous in basement
membranes, and represent the most abundant structural noncollagenous
glycoproteins of these highly specialised extracellular matrices. Their discovery
started with the difficult task of isolating molecules produced by cultivated
cells or extracted from tissues. The development of molecular biology techniques
has facilitated and accelerated the identification and the characterisation of
new laminin variants making it feasible to identify full-length polypeptides
which have not been purified. Further, genetically engineered laminin fragments
can be generated for studies of their structure-function relationship, permitting
the demonstration that laminins are involved in multiple interactions with
themselves, with other components of the basal lamina, and with cells. It endows
laminins with a central role in the formation, the architecture, and the
stability of basement membranes. In addition, laminins may both separate and
connect different tissues, i.e. the parenchymal and the interstitial connective
tissues. Laminins also provide adjacent cells with a mechanical scaffold and
biological information either directly by interacting with cell surface
components, or indirectly by trapping growth factors. In doing so they trigger
and control cellular functions. Recently, the structural and biological diversity
of the laminins has started to be elucidated by gene targeting and by the
identification of laminin defects in acquired or inherited human diseases. The
consequent phenotypes highlight the pivotal role of laminins in determining
heterogeneity in basement membrane functions.
PMID- 9758137
TI - A technique for establishing the identity of 'isolated' fossil hominin limb
bones.
AB - Associated skeletons, which are specimens preserving more than one body part from
the same individual, are especially important for taxonomic and functional
analyses. This study concentrates on the subset of associated skeletons which
preserve the reciprocal surfaces of a joint. It uses laser scanning to explore
whether the shapes of the reciprocal surfaces of a joint of an individual are
significantly more congruent than the surfaces of randomly-matched pairings taken
from the same species. Laser scanning was used to capture the distal articular
surface of the left tibia of OH35 and the trochlear articular surface of the
talus of OH8, both from Bed I, Olduvai Gorge, Tanzania. The degree of congruency
between those articular surfaces was tested against the congruency of the
talocrural joint of AL 288-1 (Australopithecus afarensis), and the congruency of
both associated and randomly-matched talocrural joints of modern humans,
chimpanzees and gorillas. The results suggest that OH35 and OH8 do not come from
the same individual and may not come from the same species. Although this
analysis leaves open the taxonomic affinity of OH35, it demonstrates the
potential of laser scanning for capturing 3D data in palaeoanthropology. It also
demonstrates the potential for using the relative congruency of reciprocal joint
surfaces as a test of the likelihood that isolated limb bones are components of a
single individual.
PMID- 9758136
TI - Splenic adherent cells, stimulated in vitro, induce the reactive formation of
lymphoid follicles and germinal centres in draining lymph nodes after
subcutaneous transfusion into syngeneic mice.
AB - The reactive formation of lymphoid follicles and germinal centres in lymph nodes,
induced by subcutaneous transfer of in vitro activated splenic adherent cells
into syngeneic mice, were studied. Adherent cells were obtained by incubating
spleen cell suspensions for 24 h and activated by incubating for 1 h in the
medium containing keyhole limpet haemocyanin (KLH) absorbed onto alumina. Some of
the treated adherent cells were irradiated with 10 Gy x-rays, while others were
either not stimulated or were stimulated with alumina-KLH but killed by repeated
freezing and thawing. Examination of adherent cell smears immunostained with
antibodies against, F4/80, Mac-1, Mac-2 and NLDC-145 indicated that many adherent
cells displayed macrophage markers but few displayed the interdigitating cell
marker. Animals transfused with KLH-treated adherent cells with or without
irradiation showed a marked increase in the number of lymphoid follicles and
germinal centres in draining lymph nodes, whereas those transfused with adherent
cells which had not been KLH-treated or which had been killed after KLH treatment
displayed no significant change in the number of follicles. These results were
interpreted as indicating that following transfusion, antigen-activated adherent
macrophages migrated into the draining lymph nodes and induced the reactive
formation of lymphoid follicles and germinal centres outside preexisting
follicles.
PMID- 9758138
TI - Morphological study by an 'in vivo cryotechnique' of the shape of erythrocytes
circulating in large blood vessels.
AB - Changes in the shape of erythrocytes circulating in large blood vessels of mice
were examined by our 'in vivo cryotechnique'. The abdominal aorta and inferior
vena cava (IVC) were cut vertically with a precooled knife and simultaneously an
isopentane-propane mixture (-193 degrees C) was poured over them for freezing.
They were freeze-substituted in acetone containing 2% osmium tetroxide. Some
specimens were embedded in Quetol-812, and thick or ultrathin sections were
examined by light or transmission electron microscopy. Serial ultrathin sections
were used to reconstruct 3-dimensional images of native erythrocytes. Others were
transferred into t-butyl alcohol and freeze-dried for scanning electron
microscopy. The tissue surfaces were sufficiently frozen to prevent large ice
crystal formation, and erythrocyte shapes were also preserved. The shapes of
circulating erythrocytes appeared to be varied in the abdominal aorta but typical
biconcave discoid shapes were rarely observed. Conversely, erythrocytes were
approximately biconcave discoid in shape in the IVC. Our in vivo cryotechnique
was useful for clarifying the in vivo morphology of erythrocytes circulating in
large blood vessels.
PMID- 9758139
TI - Morphogenesis of Doublefoot (Dbf), a mouse mutant with polydactyly and
craniofacial defects.
AB - We report the morphogenesis of a new mouse mutant, Doublefoot (Dbf). The major
phenotypic features involve the limb and craniofacial regions. There is
polydactyly of all 4 limbs, with typically 6-8 digits per limb. All of the digits
are triphalangeal; some show bifurcations and some are not attached to the
carpus/tarsus. The carpus and tarsus are broader than normal, and their elements
are partially fused. There are also tibial defects. Mutant embryos show a
diencephalic bulge on d 10.0, with older animals exhibiting broadened and bulbous
skulls sometimes with an additional midline skeletal element, shortened snouts
and bulging eyes. Homozygotes, which do not survive beyond d 15, show midline
facial clefting. In this study of the embryonic and fetal development of Dbf
animals, we focus on the morphogenesis of the limbs and head, and discuss the
possible molecular developmental mechanisms.
PMID- 9758140
TI - Morphological and functional evidence, and clinical importance, of vascular
anastomoses in the latissimus dorsi muscle of the sheep.
AB - Mobilisation of the latissimus dorsi muscle as a functional graft necessarily
involves division of perforating arteries that enter the distal portion of the
muscle, rendering it vulnerable to ischaemic damage when the muscle is stimulated
electrically. Using a fluorescent microsphere technique we showed that the blood
flow contributed by the thoracodorsal artery decreases in a proximal-to-distal
direction, and that of the perforating arteries in a distal-to-proximal
direction, but for neither does the flow decline to zero. This is consistent with
earlier reports of anastomotic connections between the 2 arterial territories. We
went on to use fluorescence microscopy to demonstrate the existence of these
vascular anastomoses, the first such evidence obtained under physiological
conditions of pressure and flow. In clinical applications, the existence of
anastomotic connections offers the prospect of maintaining flow to the distal
part of the grafted muscle without the delays inherent in neovascularisation
procedures.
PMID- 9758141
TI - Anatomy of the pig heart: comparisons with normal human cardiac structure.
AB - Transgenic technology has potentially solved many of the immunological
difficulties of using pig organs to support life in the human recipient.
Nevertheless, other problems still remain. Knowledge of cardiac anatomy of the
pig (Sus scrofa) is limited despite the general acceptance in the literature that
it is similar to that of man. A qualitative analysis of porcine and human cardiac
anatomy was achieved by gross examination and dissection of hearts with
macrophotography. The porcine organ had a classic 'Valentine heart' shape,
reflecting its location within the thorax and to the orientation of the pig's
body (unguligrade stance). The human heart, in contrast, was trapezoidal in
silhouette, reflecting man's orthograde posture. The morphologically right atrium
of the pig was characterised by the tubular shape of its appendage (a feature
observed on the left in the human heart). The porcine superior and inferior caval
veins opened into the atrium at right angles to one another, whereas in man the
orifices were directly in line. A prominent left azygous vein (comparable to the
much reduced left superior caval or oblique vein in man) entered on the left side
of the pig heart and drained via the coronary sinus. The porcine left atrium
received only 2 pulmonary veins, whereas 4 orifices were generally observed in
man. The sweep between the inlet and outlet components of the porcine right
ventricle was less marked than in man, and a prominent muscular moderator band
was situated in a much higher position within the porcine right ventricle
compared with that of man. The apical components of both porcine ventricles
possessed very coarse trabeculations, much broader than those observed in the
human ventricles. In general, aortic-mitral fibrous continuity was reduced in the
outlet component of the porcine left ventricle, with approximately two-thirds of
the aortic valve being supported by left ventricular musculature. Several
potentially significant differences exist between porcine and human hearts. It is
important that these differences are considered as the arguments continue
concerning the use of transgenic pig hearts for xenotransplantation.
PMID- 9758142
TI - A polydactylous human foot with 'double-dorsal' toes.
AB - A human polydactylous left foot with 9 toes, amputated from an 11-mo-old child,
was examined by x-ray and magnetic resonance imaging and by gross dissection to
identify the digits. The normal sequence of toes from medial to lateral is 1, 2,
3, 4, 5. Examination of the morphology of tendons and muscles suggested the toe
sequence was 1, 2, 3/4, ?5, 2, 3/4, 3/4, 5. The 2 toes in the sequence that are
underlined were displaced dorsally and were found to have 2 extensor tendons, no
flexor tendons and nails that were conical and situated at their tips. These toes
resembled those described as 'double-dorsal' and which develop in paws of mice in
which a gene normally expressed ventrally is functionally inactivated (Loomis et
al. 1996). Specification of toe formation occurs in leg buds early in embryonic
development and later there is rotation of the limb so that the anterior
(rostral) part comes to lie medially, i.e. the hallux which was anterior
(rostral) now is on the inner (medial) side of the foot. A disruption in the
patterning of this foot in both anteroposterior (rostral-caudal) and dorsoventral
axes during development could be responsible.
PMID- 9758143
TI - The morphological basis of increased stiffness of rabbit tibialis anterior
muscles during surgical limb-lengthening.
AB - When the tibialis anterior muscle of the rabbit is progressively stretched during
surgical limb distraction, the muscle fibres lengthen by addition of new serial
sarcomeres, provided that stretch is carried out at an appropriate rate. However,
in spite of the apparent adaptation to the new functional length, range of joint
movement is greatly decreased. In this study we have first, made measurements of
the passive tension developed by distracted muscles over the range of joint
movement and secondly made quantitative measurements of endomysial and perimysial
connective tissue content. It was found that at all ankle joint angles greater
than 90 degrees, the passive tension developed by the distracted muscles was
greater than both contralateral and sham-operated controls. Image analysis showed
that the ratio of collagen to contractile material was increased in distracted
muscles compared with muscles from sham-operated controls, due to increased
deposition of collagen type III. Scanning electron microscopy showed the presence
of a dense perimysial weave surrounding the distracted muscle fibres. These
quantitative and qualitative changes in the connective tissue component could
account for the increased stiffness demonstrated by the physiological
measurements. It would seem that in distracted muscle the connective tissue
element adapts less readily than the contractile component, with prolonged
stretch leading to damage to the perimysial and endomysial network, with
subsequent fibrosis and loss of muscle compliance. Such changes could help
explain the loss of range of movement noted in the distracted limbs of patients
undergoing surgical limb-lengthening and in other conditions that result in
muscle contractures.
PMID- 9758144
TI - A comparison of four in vivo methods of measuring tibial torsion.
AB - Tibial torsion, twisting of the tibia about its longitudinal axis, varies during
development and early childhood. Knowledge of the normal range of tibial torsion
at various ages and its accurate clinical measurement is important in the
assessment of the extent of a torsional deformity. To evaluate tibial torsion a
reliable technique for its measurement in vivo is therefore required. The aim of
this study was to determine which of 4 existing in vivo methods of measuring
tibial torsion was the most accurate and had the highest repeatability, by
comparing them with direct measurement of the tibia. A wide range of mean values
for tibial torsion was observed, using the various techniques, with none of the
indirect techniques employed having a strong correlation with direct measurement
of tibial torsion. The repeatability of the indirect techniques was observed to
be low both in cadavers (n = 4) and the living (n = 3). Since none of the in vivo
techniques appear to measure true tibial torsion or be of a reasonable
repeatability, alternative easy to use and inexpensive methods need to be
developed. Accurate clinical measurement of tibial torsion is important in the
assessment of the extent of a torsional deformity. It is recommended that data
gained using the methods reviewed here are interpreted with caution.
PMID- 9758145
TI - Metatarsal growth during the second trimester: a predictor of gestational age?
AB - Metatarsal growth was studied in 780 human fetal metatarsal bones, crown-rump
length ranging from 120 to 260 mm and gestational age ranging from 14 to 23 wk
postconception. Total length, diaphyseal length and diameter were measured and
statistical analysis performed. Means and standard deviations for each
measurement were calculated at 1 wk intervals. These data were correlated with
crown-rump length and gestational age and an equation was constructed in an
attempt to predict gestational age.
PMID- 9758146
TI - Expression of the mRNA for the beta 2 subunit of the voltage-dependent sodium
channel in rat CNS.
AB - Expression of the voltage-dependent sodium channel has been analysed in adult rat
central nervous system by Northern blotting and in situ hybridization. Northern
blots showed that all the territories studied express beta 2 transcripts, albeit
with widely varying levels (with cerebellum >> hippocampus > brain > brainstem >
spinal cord). In situ hybridization confirmed that in these structures, all the
neuronal cell bodies contain beta 2 mRNA; expression was particularly high in the
granule cells of the cerebellum, in both pyramidal cell layer and dentate gyrus
in the hippocampus, and in spinal cord motor neurons. Northern blots also showed
that RNA extracted from optic nerve and cultured cortical astrocytes contained
beta 2 mRNA, while it was totally absent from sciatic nerve. In situ
hybridization evidenced the presence of a numerous population of beta 2-positive
cells in cerebellum white matter, spinal cord white matter, and in corpus
callosum, where frontal sections showed labelled cells arranged in the chain-like
or row pattern typical of interfascicular oligodendrocytes. Combination of
antiglial fibrillary acid protein (GFAP) immunofluorescent histochemistry with
detection of beta 2 mRNA evidenced that expression of the transcripts was indeed
restricted to GFAP-negative cells in white matter.
PMID- 9758147
TI - Reduction of advanced glycation end-product (AGE) levels in nervous tissue
proteins of diabetic Lewis rats following islet transplants is related to
different durations of poor metabolic control.
AB - Advanced glycation end-products (AGEs) are irreversible compounds which, by
abnormally accumulating over proteins as a consequence of diabetic
hyperglycaemia, can damage tissues and thus contribute to the pathogenesis of
diabetic complications. This study was performed to evaluate whether restoration
of euglycaemia by islet transplantation modifies AGE accumulation in central and
peripheral nervous tissue proteins and, as a comparison, in proteins from a non
nervous tissue. Two groups of streptozotocin diabetic inbred Lewis rats with 4
(T1) or 8 (T2) months disease duration were grafted into the liver via the portal
vein with 1200-1500 islets freshly isolated from normal Lewis rats. Transplanted
rats, age-matched control and diabetic rats studied in parallel, were followed
for a further 4-month period. At study conclusion, glycaemia, glycated
haemoglobin and body weight were measured in all animals, and an oral glucose
tolerance test (OGTT) performed in transplanted rats. AGE levels in cerebral
cortex, spinal cord, sciatic nerve proteins and tail tendon collagen were
measured by enzyme-linked immunosorbent assay (ELISA). Transplanted animal OGTTs
were within normal limits, as were glycaemia and glycated haemoglobin. Diabetic
animal AGEs were significantly higher than those of control animals. Protein AGE
values were reduced in many transplanted animals compared to diabetic animals,
reaching statistical significance in spinal cord (P < 0.05), sciatic nerve (P <
0.02) and tail tendon collagen (P < 0.05) of T1 animals. Thus, return to
euglycaemia following islet transplantation after 4 months of diabetes with poor
metabolic control reduces AGE accumulation rate in the protein fractions of the
mixed and purely peripheral nervous tissues (spinal cord and sciatic nerve,
respectively). However, after a double duration of bad metabolic control, a
statistically significant AGE reduction has not been achieved in any of the
tissues, suggesting the importance of an early therapeutic intervention to
prevent the possibly pathological accumulation of AGEs in nervous and other
proteins.
PMID- 9758148
TI - Beta-adrenergic and fibroblast growth factor receptors induce neuronal process
outgrowth through different mechanisms.
AB - The mechanisms that initiate and direct neuronal process formation remain poorly
understood. We have recently described a neuronal progenitor cell line, AS583
8.E4.22 (AS583-8) which undergoes neurite formation in response to beta2
adrenergic and basic fibroblast growth factor (bFGF) receptor activation [Kwon,
J.H. et al., (1996) Eur. J. Neurosci., 8, 2042-2055]. In the present study, a
comparison of these responses revealed that isoproterenol (ISO), a beta
adrenergic receptor agonist, induces multiple, highly branched processes within
30 min while bFGF induces fewer, unbranched processes within 24 h. In contrast to
the ISO response, bFGF induces mitogen-activated protein kinase activation and c
fos expression in the cell line and results in neurite outgrowth that is
dependent on new mRNA and protein synthesis. Two-dimensional isoelectric focusing
sodium dodecyl sulphate-polyacrylamide gel electrophoresis of cytoskeletal
preparations revealed different patterns following ISO vs. bFGF exposure
suggesting selective changes in protein expression and/or post-translational
modifications. Immunoblot analysis of these preparations for beta-tubulin,
tyrosinated alpha-tubulin and acetylated alpha-tubulin also revealed different
patterns following each type of treatment. Follow-up confocal microscopy revealed
that following ISO, the distribution of tyrosinated tubulin extends to the distal
ends of processes whereas acetylated alpha-tubulin is diminished within distal
ends. This pattern has been reported to be associated with enhanced microtubule
dynamics, a state in which process outgrowth is facilitated. In contrast,
following bFGF treatment the distributions of tyrosinated and acetylated alpha
tubulin were identical, a state associated with a diminution of microtubule
dynamics. These results, a different time course of neurite formation, dependency
on new gene expression and differential expression and cellular distribution of
major cytoskeleton proteins suggest that neurite outgrowth induced by ISO vs.
bFGF is mediated by two distinct intracellular effector mechanisms in AS583-8
cells. In addition, studies, using the differential distribution of post
translational modified alpha-tubulins in neurites of primary neuronal cultures as
marker for the two distinct processes of neurite formation suggest, that similar
mechanisms are present in vivo. Therefore, the AS583-8 cell line provides a
useful model to study these signalling mechanisms that couple neurotransmitter
and growth factor receptor activation to the cytoskeletal changes that mediate
neurite formation.
PMID- 9758149
TI - Electrophysiological and neurochemical study of the rat geniculo-cortical
pathway. Evidence for glutamatergic neurotransmission.
AB - The projection from the dorsal lateral geniculate nucleus to the primary visual
cortex of the rat was studied electrophysiologically. Electrical stimulation of
the dorsal lateral geniculate nucleus and the optic tract produced three types of
responses on neurons of area 17: excitation followed by inhibition, excitation
and inhibition. These results extend and confirm, in adult rats, previous studies
done in rat geniculate-visual cortex cocultures preparations in vitro. The role
of glutamate in the neurotransmission of the rat geniculo-cortical pathway was
also investigated. In a first set of experiments, the effects of kynurenate, an
antagonist of glutamate receptors, on visual cortex neurons with a monosynaptic
excitatory response to dorsal lateral geniculate nucleus stimulation were
studied. Microiontophoresis of kynurenate in area 17 neurons selectively
suppressed the excitatory response to dorsal lateral geniculate nucleus and optic
tract stimulation. In a second set of experiments, the effects of electrical
stimulation of the dorsal lateral geniculate nucleus and the optic tract on the
release of amino acids in the rat visual cortex in vivo were studied. Using the
push-pull method, we perfused a discrete region of the visual cortex with
artificial cerebrospinal fluid (CSF), and the amino acid content of the
perfusates was analysed by high performance liquid chromatography (HPLC).
Stimulation of either the dorsal lateral geniculate nucleus or the optic tract
significantly increased glutamate release in area 17. The rest of the amino acids
studied did not show significant changes. The results provide evidence for the
participation of glutamate in the neurotransmission of the geniculo-cortical
pathway in the rat.
PMID- 9758150
TI - Regional brain variations of cytochrome oxidase activity and motor coordination
in hot-foot mutant mice.
AB - Hot-foot mutant mice are characterized by defective arborization of Purkinje cell
dendrites, resulting in ataxia of gait and deficits of equilibrium. Regional
brain variations of cytochrome oxidase (CO) activity were analysed for the
purpose of identifying those brain regions with abnormal metabolic activity as a
secondary consequence to the cerebellar alteration. In addition, the possible
relation between CO activity and motor deficits was evaluated. By comparison to
normal littermate controls of the same background strain, hot-foot mutants had
higher CO activity in the molecular layer of the cerebellum, the ventrolateral
and midline thalamic nuclei, as well as in the frontal eye field. There was no
other alteration of CO activity in the hot-foot brain. No linear correlation was
discerned between CO activity in the molecular layer of the cerebellum and the
ventrolateral and midline nuclei on one hand, and motor coordination performance
on the other. These results indicate regionally selective abnormalities of
metabolic activity in a cerebellar mutant with defective dendritic arborization
of the Purkinje cell.
PMID- 9758152
TI - Increase in meso-prefrontal dopaminergic activity after stimulation of CB1
receptors by cannabinoids.
AB - The intravenous administration of the psychoactive constituent of marijuana,
delta9-tetrahydrocannabinol (delta9-THC) (62.5-1000 microg/kg), and the synthetic
cannabinoid agonist WIN 55212,2 (WIN) (62.5-500 microg/kg), produced a dose
related increase in the firing rate and burst firing in the majority of
antidromically identified meso-prefrontal dopaminergic neurons. In a restricted
number of neurons (n=4), WIN administration did not increase firing rate but
produced an increment of bursting activity. These effects of the cannabinoids
were reversed by the intravenous administration of SR 141716 A, a selective
cannabinoid antagonist (1 mg/kg), per se ineffective to modify the electrical
activity of dopaminergic neurons. The results indicate that stimulation of
cannabinoid CB1 receptors produces an activation of meso-prefrontal dopaminergic
transmission. Considering that supranormal stimulation of D1 dopamine receptors
in the prefrontal cortex has been shown to impair working memory, the present
results suggest that the negative effects of cannabinoids on cognitive processes
might be related to the activation of dopaminergic transmission in the prefrontal
cortex.
PMID- 9758153
TI - Neuronal coding of interaural transient envelope disparities.
AB - Onsets are salient and important transient (i.e. dynamic) features of acoustic
signals, and evoke vigorous responses from most auditory neurons, but
paradoxically these onset responses have most often been analysed with respect to
steady-state stimulus features, e.g. the sound pressure level (SPL). In nearly
all studies concerned with the coding of differences in SPL at the two ears
(interaural level differences; ILDs), which provide a major cue for the azimuthal
location of high frequency sound sources, interaural onset disparities were
covaried with ILD, but the possibly confounding effects of this covariation on
neuronal responses have been entirely neglected. Therefore, dichotic stimulus
paradigms were designed here in which onset and steady-state features were varied
independently. Responses were recorded from single neurons in the inferior
colliculus of rats, anaesthetized with pentobarbital and xylazine. It is
demonstrated that onset responses, or the onset response components of neurons
with more complex temporal response patterns, are dependent on the binaural
combination of dynamic envelope features associated with conventional ILD
stimulus paradigms, but not on the binaural combination of steady-state SPLs
reached after the onset. In contrast, late or sustained response components
appear more sensitive to the binaural combination of steady-state SPLs. These
data stress the general necessity for a separate analysis of onset and late
response components, with respect to different stimulus features, and suggest a
need for re-evaluation of existing studies on ILD coding. The sensitivity of
onset responses to the binaural combination of envelope transients, rather than
to steady-state ILD, is in line with their sensitivity to other interaural
envelope disparities, created by stationary or moving sounds.
PMID- 9758151
TI - MuSC, a novel member of the immunoglobulin superfamily, is expressed in neurons
of a subset of cranial sensory ganglia in the mouse embryo.
AB - In contrast to the spinal sensory ganglia which reiterate a basic organizational
and functional unit, each cranial ganglion mediates a distinct sensory modality
and exhibits a characteristic pattern of peripheral and central neuronal
connectivity. Molecules responsible for establishment and maintenance of the
cranial ganglion-specific networks are not known. Our hamster monoclonal antibody
802C11 strongly stained neurons and their processes of the VIIIth cranial
ganglion (hearing and equilibrium), but not of the Vth cranial (somatosensory) or
spinal ganglia in the mouse embryo. The cellular staining pattern of positive
neurons suggested that the antigen was associated with the cell membrane, and
biochemical analyses of the antigen from adult mouse brain showed the antigen to
be a glycosylated intrinsic membrane protein of approximately 100 kDa. The
antigen was purified, and based on the partial amino acid sequences, its entire
cDNA was cloned. A bacterially expressed polypeptide encoded by the cDNA was
recognized by the antibody. The deduced amino acid sequence revealed that the
antigen belongs to the immunoglobulin superfamily with a significant homology
(73.5% identity) to chicken SC1 protein. Chicken SC1 has been shown to be a cell
cell adhesion molecule in vitro with a proposed role in neurite extension of
spinal motor neurons. These results suggest that our murine SC1-related protein
(MuSC) is involved in the pathfinding and/or fasciculation of specific cranial
sensory nerve fibres.
PMID- 9758154
TI - Antagonists for group I mGluRs attenuate excitotoxic neuronal death in cortical
cultures.
AB - Activation of ion channel-linked glutamate receptors, especially N-methyl-D
aspartate (NMDA) receptors, mediates the excitotoxic effects of glutamate upon
central neurons. We examined the hypothesis that activation of group I
metabotropic glutamate receptors (mGluRs) would increase NMDA receptor-mediated
cortical neuronal death. Addition of the selective group I mGluR agonists,
dihydroxyphenylglycine (DHPG) or trans-azetidine-2,4-dicarboxylic acid (t-ADA)
potentiated NMDA-induced neuronal death, and application of the group I mGluR
selective antagonist, aminoindan-1,5-dicarboxylic acid (AIDA), as well as the non
selective antagonists methyl-4-carboxyphenylglycine (MCPG) or 4
carboxyphenylglycine (4CPG) reduced NMDA- and kainate-induced neuronal death in
murine cortical cultures. The pro-excitotoxic effect of group I mGluR activation
may be mediated largely by enhancement of glutamate release, as DHPG potentiated
high potassium-stimulated glutamate release, and the protective effects of both
AIDA and MCPG were abolished when NMDA and alpha-amino-3-hydroxy-5-methyl-4
isoxazole proprionic acid (AMPA) receptors were blocked immediately after toxic
NMDA receptor overstimulation. The present data support the possibility that
antagonizing group I mGluRs may be a useful strategy for attenuating excitotoxic
neuronal death in certain disease states.
PMID- 9758155
TI - Co-localized neuropeptide Y and GABA have complementary presynaptic effects on
sensory synaptic transmission.
AB - We have examined the morphological relationship of neuropeptide Y (NPY) and
GABAergic neurons in the lamprey spinal cord, and the physiological effects of
NPY and GABA(B) receptor agonists on afferent synaptic transmission. NPY
containing fibres and cell bodies were identified in the dorsal root entry zone.
NPY immunoreactive (-ir) fibres made close appositions with primary afferent
axons. Co-localization of NPY and GABA-ir was found in the dorsal horn and dorsal
column. Fifty-two per cent of NPY-ir profiles showed immunoreactivity to GABA at
the ultrastructural level. Electron microscopic analysis showed that NPY
immunoreactivity was present throughout the axoplasm, including over dense core
vesicles, whereas GABA-immunoreactivity was mainly found over small synaptic
vesicles. Synthetic lamprey NPY, and the related peptide, peptide YY, reduced the
amplitude of monosynaptic afferent EPSPs in spinobulbar neurons. NPY had no
significant effect on the postsynaptic input resistance or membrane potential,
the electrical component of the synaptic potential, or the response to glutamate,
but it could reduce the duration of presynaptic action potentials, suggesting
that it was acting presynaptically. NPY also reduced the excitability of the
spinobulbar neurons, suggesting at least one postsynaptic effect. Because NPY and
GABA colocalize, we compared the effects of NPY and the GABA(B) agonist baclofen.
Both presynaptically reduced EPSP amplitudes, baclofen having a larger effect and
a faster onset and recovery than NPY. The GABA(B) antagonist phaclofen reduced
the effect of baclofen, but not that of NPY. We conclude that NPY and GABA are
colocalized in terminals in the dorsal spinal cord of the lamprey, and that they
have complementary actions in modulating sensory inputs.
PMID- 9758156
TI - Network bursting by organotypic spinal slice cultures in the presence of
bicuculline and/or strychnine is developmentally regulated.
AB - Organotypic cocultures of dorsal root ganglia and spinal cord from embryonic rats
provides direct access to spinal interneurons in a culture system in which the
cytoarchitectural organization of the spinal cord slice is maintained. This
preparation was used to investigate the possible induction of rhythmic behaviour
at different times of development in vitro. Spontaneous rhythmic bursts induced
by coapplication of strychnine (1 microM) and bicuculline (20 microM) were
observed with patch-clamp recordings from ventral interneurons. Ventral horn
interneurons consistently developed a very regular pattern of activity which was
superimposed on a background of sustained synaptic activity. The pattern of the
spontaneous bursting following application of strychnine and bicuculline showed a
developmentally regulated difference in frequency between two distinct stages of
in vitro development.
PMID- 9758157
TI - Neuroactive steroids induce GABA(A) receptor-mediated depolarizing postsynaptic
potentials in hippocampal CA1 pyramidal cells of the rat.
AB - Intracellular recordings were performed in area CA1 pyramidal cells of rat
hippocampal slices to determine the effects of certain steroids on inhibitory
postsynaptic potentials/currents (IPSP/Cs) mediated by GABA(A) receptors.
Following application of the steroids 5alpha-pregnan-3alpha,21-diol-20-one
(5alpha-THDOC), alphaxalone and 5beta-pregnan-3alpha-ol-20-one (pregnanolone)
hyperpolarizing PSPs developed into biphasic responses consisting of an early
hyperpolarizing and a late depolarizing PSP sequence. Steroid-induced
depolarizing PSPs could be elicited in the presence of antagonists to non-NMDA,
NMDA, and GABA(B) receptors, indicating that these receptor types do not
contribute significantly to the initiation of these responses. Depolarizing PSPs
were completely blocked by both GABA(A) receptor antagonists bicuculline and t
butylbicyclophosphorothionat (TBPS) providing evidence for their mediation by
GABA(A) receptors. The reversal potential of steroid-induced late inward PSCs,
measured in single-electrode voltage clamp, was -29.9+/-5.3 mV, whereas the early
outward current, which corresponded to the early hyperpolarizing component of
PSPs, reversed at -68.2+/-1.5 mV. Depolarizing PSPs and late inward PSCs were
sensitive to reduction of extracellular [HCO3-] and block of carbonic anhydrase
by application of acetazolamide. The results suggest that certain neuroactive
steroids can induce GABA(A) receptor-mediated depolarizing PSPs, which are
dependent on HCO3-.
PMID- 9758159
TI - Rhythmic variation in beta1-adrenergic receptor mRNA levels in the rat pineal
gland: circadian and developmental regulation.
AB - In the rat pineal gland noradrenaline is released in large quantities from
sympathetic nerve endings at the onset of darkness, thereby driving rhythmic
melatonin synthesis with elevated levels at night-time. Upon release,
noradrenaline interacts with postsynaptic beta1-adrenergic receptors to activate
the cyclic AMP signalling pathway. Well characterized third messengers of this
signalling cascade affect cyclic AMP-inducible genes that are crucially involved
in initiation, maintenance and termination of hormone production. Among these
third messengers are CREB (cyclic AMP responsive element binding protein) as an
activating and ICER (inducible cyclic AMP early repressor) as an inhibitory
transcription factor. Because a cyclic AMP-inducible promoter element is present
on the beta1-adrenergic receptor gene, the expression of the receptor itself may
be under control of the cyclic AMP-signalling pathway. By in situ hybridization,
Northern blot analysis and RT-PCR we demonstrate a day/night rhythm in beta1
adrenergic receptor mRNA in the rat pineal gland with elevated levels during the
dark period. As this rhythm persists, under constant darkness but is abolished
upon removal of the sympathetic innervation, it is truly circadian. A marked
day/night difference in the levels of beta1-adrenergic receptor mRNA becomes
evident only after postnatal day 10, coinciding with the appearance of a
functional cyclic AMP signalling pathway in the rat pineal gland. Furthermore,
targeting ICER expression by transfection of pinealocytes with an antisense ICER
construct, clearly indicates that the levels of the beta1-adrenergic receptor
mRNA are regulated by the cyclic AMP-signalling pathway in a feedback mechanism.
PMID- 9758160
TI - Molecular and functional adaptation of the GABA(A) receptor complex during
pregnancy and after delivery in the rat brain.
AB - The abundance of gamma-aminobutyric acid receptor type A (GABAA receptor) subunit
mRNAs and polypeptides as well as muscimol-stimulated 36Cl- uptake were measured
in rat cerebral cortex or hippocampus at various times during pregnancy and after
delivery. RNase protection assays revealed that the amount of the gamma2L subunit
mRNA decreased progressively during pregnancy, in the cerebral cortex and
hippocampus, and then returned to control values around the time of delivery. A
similar pattern was observed for the alpha5 subunit mRNA in the cerebral cortex,
whereas no significant changes were apparent for alpha1, alpha2, alpha3, alpha4,
beta1, beta2, beta3 and gamma2S subunit mRNAs. The amounts of gamma2 and alpha1
proteins in the cerebral cortex were measured by immunoblot analysis; whereas the
abundance of gamma2 protein decreased during pregnancy, no change was detected in
the amount of alpha1 protein. Evaluation for functional significance of the down
regulated gamma2 and alpha5 subunit was made by determining the GABAA receptor
function assessed by measurement of muscimol-stimulated 36Cl- uptake in cerebral
cortical membrane vesicles. Muscimol-induced 36Cl- uptake was markedly reduced
during of pregnancy compared with rats in oestrus. At this same time, the
potentiating effects of diazepam and allopregnanolone on muscimol stimulation of
36Cl- uptake also were reduced. In contrast, the effects of muscimol,
allopregnanolone and diazepam were significantly increased, relative to animals
in oestrus, after delivery.
PMID- 9758158
TI - Endogenous ACh enhances striatal NMDA-responses via M1-like muscarinic receptors
and PKC activation.
AB - Cortical glutamatergic fibres and cholinergic inputs arising from large aspiny
interneurons converge on striatal spiny neurons and play a major role in the
control of motor activity. We have investigated the interaction between
excitatory amino acids and acetylcholine (ACh) on striatal spiny neurons by
utilizing intracellular recordings, both in current- and in voltage-clamp mode in
rat brain slices. Muscarine (0.3-10 microM) produced a reversible and dose
dependent increase in the membrane depolarizations/inward currents induced by
brief applications of N-methyl-D-aspartate (NMDA), while it did not affect the
alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-induced responses.
These concentrations of muscarine did not alter the membrane potential and the
current-voltage relationship of the recorded cells. Neostigmine (0.3-10 microM),
an ACh-esterase inhibitor, mimicked this facilitatory effect. The facilitatory
effects of muscarine and neostigmine were antagonized either by scopolamine (3
microM) or by pirenzepine (10-100 nM), an antagonist of M1-like muscarinic
receptors, but not by methoctramine (300 nM), an antagonist of M2-like muscarinic
receptor. Accordingly, these facilitatory effects were mimicked by McN-A-343 (1
10 microM), an agonist of M1-like muscarinic receptors, but not by oxotremorine
(300 nM), an agonist of M2-like receptors. Tetrodotoxin (TTX) did not block the
facilitatory effect produced by the activation of muscarinic receptors suggesting
that this effect is postsynaptically mediated. The action of neostigmine was
prevented either by the intracellular calcium (Ca2+) chelator BAPTA (200 mM) or
by preincubating the slices with inhibitors of protein kinase C (PKC)
(staurosporine 100 nM or calphostin C 1 microM). McN-A-343 did not alter the
excitatory post synaptic potentials (EPSPs) evoked by corticostriatal stimulation
in the presence of physiological concentration of magnesium (Mg2+ 1.2 mM), while
it enhanced the duration of these EPSPs recorded in the absence of external
magnesium. Our data show that endogenous striatal ACh exerts a positive
modulatory action on NMDA responses via M1-like muscarinic receptors and PKC
activation.
PMID- 9758161
TI - Survival motor neuron (SMN) protein in rat is expressed as different molecular
forms and is developmentally regulated.
AB - Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by
a progressive degeneration of motoneurons in spinal cord and brainstem. The
telomeric copy of a duplicated gene termed survival motor neuron (smn), which
maps to chromosome 5q13, has been found to be deleted in most patients. The
encoded gene product is a novel protein which recently has been shown to
accumulate in specific nuclear organelles (gemini of coiled bodies, GEMS), and to
play a part in the formation of the spliceosome complex. We have cloned and
sequenced the rat smn cDNA. Antibodies generated against an N-terminus peptide
recognized a main protein of 32 kDa in immunoblots of rat embryonic tissue
extracts. Minor bands of 35 kDa, 45 kDa and, in perinatal muscle, of 24 kDa were
also specifically detected, indicating that SMN is expressed as different
molecular forms. Subcellular fractionation indicated that the 32 kDa form is
mainly soluble, while the 35 kDa and 45 kDa products segregate to the microsomal
mitochondrial fraction. SMN protein is highly regulated during development:
expression is high in embryonic tissues (central nervous system, muscle, lung and
liver), and then progressively decreases to very low levels in most tissues of
the adult. The demonstration of different molecular forms of SMN along with its
developmental regulation may help to understand the contribution of this protein
in the appearance of SMA phenotype.
PMID- 9758162
TI - Evidence for a GABAergic projection from the central nucleus of the amygdala to
the brainstem of the macaque monkey: a combined retrograde tracing and in situ
hybridization study.
AB - The central nucleus of the amygdala is interconnected with a variety of visceral
and autonomic nuclei of the brainstem. These include the parabrachial nucleus,
the nucleus of the solitary tract, the nucleus ambiguus and the dorsal motor
nucleus of the vagus. Despite repeated attempts, neurochemical characterization
of the major subcortical connections of the central nucleus has not yet been
accomplished. Based on earlier immunohistochemical and in situ hybridization
evidence indicating the presence of numerous GABAergic neurons in the macaque
monkey central nucleus, we predicted that a sizeable portion of the descending
projections may be GABAergic. We tested this hypothesis using a novel double
labelling method with gold conjugated WGA-apoHRP as a retrograde tracer and in
situ hybridization for detecting the mRNA that encodes the enzyme glutamic acid
decarboxylase (GAD67) as a marker for GABAergic cells. Following WGA-apoHRP-gold
injections into the brainstem, a large number of retrogradely labelled cells was
observed in the medial and lateral divisions of the central nucleus. Of the
retrogradely labelled cells observed in the medial division of the central
nucleus, approximately half were double-labelled for GAD67 mRNA; about 30% double
labelling was observed in the lateral division. These data support the view that
a sizeable component of the central nucleus projection to the brainstem is
GABAergic.
PMID- 9758164
TI - Excitatory convergence of Y and non-Y channels onto single neurons in the
anterior ectosylvian visual area of the cat.
AB - Numerous functional and hodological studies of the anterior ectosylvian visual
area (AEV) of the cerebral cortex of the cat suggest that this area plays an
important role in processing information about visual motion. In the present
study, in cats with selective conduction block of Y fibres in one optic nerve, we
have examined the extent of the excitatory convergence of Y (presumed 'motion
channel') and non-Y information channels on single neurons in AEV, as well as the
contribution of the Y channel to the receptive field properties of AEV neurons.
While in normal cats all neurons recorded from AEV were binocular, i.e. could be
photically activated via either eye, in cats with selective conduction block of Y
fibres in one optic nerve, a significant proportion (about 15%) of AEV cells
could be photically activated only via the normal eye. In comparison to those in
normal cats, the peak discharge rates of AEV neurons in the Y-blocked cats were
drastically reduced not only when photic stimuli were presented via the Y-blocked
eye, but also when they were presented via the normal eye. Selective block of Y
input also resulted in a significant shift in velocity preferences towards the
lower velocities. However, the direction selectivity indices of AEV neurons were
not affected by selective Y block. Thus: (i) the responses of AEV neurons to a
high velocity of motion are dependent on the integrity of the Y input; (ii) the
'spontaneous' (i.e. not photically evoked) discharges of Y retinal ganglion cells
exert a facilitatory influence on the responses of AEV cells to photic stimuli;
(iii) although the responses of AEV neurons are dominated by the Y inputs, AEV
neurons also receive significant non-Y excitatory inputs; and (iv) the strong
direction selectivity revealed in most AEV neurons does not dependent on the
integrity of Y input.
PMID- 9758163
TI - Evidence for functional native NMDA receptors activated by glycine or D-serine
alone in the absence of glutamatergic coagonist.
AB - In this study we have examined the effects of N-methyl-D-aspartate (NMDA)
receptor activation on the release of cholecystokinin and somatostatin from rat
neocortical nerve endings. The release of cholecystokinin-like immunoreactivity
(CCK-LI) and of somatostatin-like immunoreactivity (SRIF-LI) elicited by 12 mM K+
from superfused synaptosomes, but not the spontaneous release, was increased by
NMDA in a concentration-dependent manner. The effects of NMDA could be prevented
by antagonists selective for the glutamate recognition site, the receptor channel
and the glycine site of the NMDA receptor. In the absence of NMDA, glycine
increased on its own and in a concentration-dependent manner the depolarization
evoked release of both CCK-LI and SRIF-LI. This effect of glycine was strychnine
insensitive and could be mimicked by D-serine, a stereoselective agonist at the
NMDA receptor glycine site. Antagonists selective for the glycine site or for the
NMDA receptor channel prevented the effects of glycine/D-serine; these effects
were, however, insensitive to blockade of the glutamate recognition site of the
NMDA receptor, suggesting that glutamate released from synaptosomes or present as
contaminant was not involved. The neuropeptide release elicited by D-serine was
strongly inhibited by ifenprodil (0.3 microM) and by Zn2+ ions (50 nM), selective
ligands at the NR2B and NR2A subunits of NMDA receptors, respectively. It is
concluded that nerve terminals of CCK- and SRIF-releasing neurons possess non
conventional NMDA receptors whose channels can be operated by glycine or D-serine
without apparent activation of the glutamatergic coagonist site. These receptors
may display the triple subunit combination NR1/NR2A/NR2B.
PMID- 9758165
TI - A novel form of long-term depression in the CA1 area of the adult rat hippocampus
independent of glutamate receptors activation.
AB - In young rats, low frequency (1-2 Hz) stimulation of the Schaffer collaterals for
15 min induces in the CA1 area of the hippocampus a homosynaptic and N-methyl-D
aspartate receptor-dependent form of long-term depression (LTD) of synaptic
efficacy. In the adults, while a similar stimulation paradigm is able to depress
previously potentiated synapses, it leads to conflicting results when applied to
naive synapses. In the present experiments, different stimulation paradigms have
been used to induce LTD in the CA1 area of the adult rat hippocampus in vitro.
Thus, stimulation of the afferent pathway at frequencies higher than those used
to produce LTD in young animals (5-10 Hz, for 15 min) reliably induced a
homosynaptic form of LTD. This form of LTD was associated with a significant
increase in paired-pulse facilitation ratio and was insensitive to ionotropic
(CNQX, 10 microM and CPP, 20 microM) and metabotropic (S-MCPG, 1 mM) glutamate
receptors antagonists, suggesting a presynaptic mechanism for both LTD induction
and expression. In conclusion, our experiments clearly show that LTD is not a
purely developmental phenomenon but is present also in mature rats, which possess
the whole machinery for LTD induction and this will greatly enhance the
flexibility and the storing capacity of neuronal circuits.
PMID- 9758166
TI - Odour coding is bilaterally symmetrical in the antennal lobes of honeybees (Apis
mellifera).
AB - The primary olfactory neuropil, the antennal lobe (AL) in insects, is organized
in glomeruli. Glomerular activity patterns are believed to represent the across
fibre pattern of the olfactory code. These patterns depend on an organized
innervation from the afferent receptor cells, and interconnections of local
interneurons. It is unclear how the complex organization of the AL is achieved
ontogenetically. In this study, we measured the functional activity patterns
elicited by stimulation with odours in the right and the left AL of the same
honeybee (Apis mellifera) using optical imaging of the calcium-sensitive dye
calcium green. We show here that these patterns are bilaterally symmetrical (n=25
bees). This symmetry holds true for all odours tested, irrespective of their role
as pheromones or as environmental odours, or whether they were pure substances or
complex blends (n=13 odours). Therefore, we exclude that activity dependent
mechanisms local to one AL determine the functional glomerular activity. This
identity is genetically predetermined. Alternatively, if activity dependent
processes are involved, bilateral connections would have to shape symmetry, or,
temporal constraints could lead to identical patterns on both sides due to their
common history of odour exposure.
PMID- 9758167
TI - Synergistic stimulation of MHC class I and IRF-1 gene expression by IFN-gamma and
TNF-alpha in oligodendrocytes.
AB - In order to understand the molecular basis of the synergistic action of
interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) on rat
oligodendrocyte development, we studied some aspects of the signalling pathways
involved in the regulation of the major histocompatibility complex (MHC) class I
and the interferon regulatory factor 1 (IRF-1) gene expression. Two well-defined
inducible enhancers of the MHC class I gene promoter, the MHC class I regulatory
element (MHC-CRE) and the interferon consensus sequence (ICS), were analysed.
Neither IFN-gamma nor TNF-alpha was capable of inducing MHC-CRE binding activity
when administrated alone. Following the exposure of oligodendrocytes to IFN
gamma, TNF-R1 expression was transcriptionally induced by the binding of signal
transducer and activator of transcription (STAT-1) homodimers to the IFN-gamma
activated site (GAS) present in the gene promoter. The upregulation of TNF-R1
allowed TNF-alpha to induce the binding of nuclear factor-kappaB (NF-kappaB) to
the MHC-CRE site. With respect to ICS element, IFN-gamma induced IRF-1 binding,
that was further enhanced upon co-treatment with TNF-alpha. The existence of a
synergism between IFN-gamma and TNF-alpha in stimulating IRF-1 expression at the
transcriptional level was supported by IRF-1 promoter analysis: IFN-gamma
directly induced the binding of STAT-1 homodimers to the GAS element, while NF
kappaB binding to the kappaB sequence was activated by TNF-alpha only after IFN
gamma treatment. This transcriptional regulation of IRF-1 gene by IFN-gamma and
TNF-alpha was confirmed at the mRNA level. The synergism demonstrated in the
present study highlights the importance of cytokine interactions in magnifying
their biological effects during brain injury and inflammation.
PMID- 9758168
TI - Both ET(A) and ET(B) receptors are involved in mitogen-activated protein kinase
activation and DNA synthesis of astrocytes: study using ET(B) receptor-deficient
rats (aganglionosis rats).
AB - Endothelin (ET) is known to be a potent mitogen in astrocytes. However, the
contribution and signalling pathway of ET(A) and/or ET(B) receptor to the
proliferation of astrocytes remain unclear. We investigated ET-induced DNA
synthesis in astrocytes using ET(B) receptor-deficient mutant rats (aganglionosis
rats: sl/sl). Western blotting with anti-ET receptor subtype-specific antibodies
and Scatchard analysis of binding revealed that ET(B) receptor expression in
astrocytes depended on gene dosage (+/+: sl/+: sl/sl=2: 1:0), whereas ET(A)
receptor expression was unchanged among the three genotypes. ET-1 (10 nM)
stimulated [3H]thymidine incorporation and mitogen-activated protein kinase (MAP
kinase) activity not only in +/+ via both ET(A) and ET(B) receptors, but also in
sl/sl astrocytes via ET(A) receptor with about half the extent of those observed
in +/+ astrocytes. Treatment with pertussis toxin (PTX) suppressed the ET-1
induced increases in the incorporation and MAP kinase activity in +/+, but not
sl/sl astrocytes, indicating that the ET(B) receptor-, but not the ET(A) receptor
, mediated pathway to DNA synthesis involves PTX-sensitive G proteins, e.g. Gi
and/or Go (Gi/o). In +/+ astrocytes, ET-1 (1 nM) stimulated cAMP accumulation,
and the ET(B) receptor-selective agonist IRL 1620 (1 nM) suppressed 10 microM
forskolin-induced cAMP accumulation, suggesting Gs coupling to the ET(A) receptor
and Gi/o coupling to the ET(B) receptor. On the other hand, ET-1 did not increase
cAMP accumulation in sl/sl astrocytes, although ET-1 (1 nM) suppressed the
forskolin-induced response, suggesting Gi/o coupling to the ET(A) receptor. Our
results suggest the possibility that the selectivity of G protein for ET(A)
receptor is changed from Gs to Gi/o in ET(B) receptor-deficient astrocytes.
PMID- 9758169
TI - Complex regulation of the expression of the polysialylated form of the neuronal
cell adhesion molecule by glucocorticoids in the rat hippocampus.
AB - The gyrus dentatus is one of the few areas of the brain that continues to produce
neurons after birth. The newborn cells differentiate into granule cells which
project axons to their postsynaptic targets. This step is accompanied by the
transient expression of the polysialylated isoforms of neuronal cell adhesion
molecules (PSA-NCAM) by the developing neurons. Glucocorticoid hormones have been
shown to inhibit neurogenesis. We noted a functional correlation between PSA-NCAM
expression and glucocorticoid action after manipulation of corticosterone levels
in the adrenalectomized rat. Adrenalectomy increased neurogenesis, evaluated from
the incorporation of 5-bromo-2'-deoxyuridine in neuronal precursors, as well as
PSA-NCAM expression. The increase in PSA-NCAM-immunoreactive (IR) cells in the
gyrus dentatus, evidenced 72 h following adrenalectomy, persisted for at least a
month. It was accompanied by enhanced dendritic arborization of PSA-NCAM-IR cells
in the gyrus dentatus and by an increase in number of PSA-NCAM-IR fibres in the
CA3 subfield. Neurogenesis was normalized by restitution of diurnal or nocturnal
levels of corticosterone, whereas normalization of PSA-NCAM expression was only
observed after simulation of the complete circadian fluctuation of the hormone.
Our findings reveal the complex action of corticosterone in modulating the
expression of PSA-NCAM in the gyrus dentatus of the hippocampal formation. They
also highlight the importance of corticosterone fluctuations in the control of
neurogenesis and plasticity in this structure.
PMID- 9758170
TI - Neurotrophin-3 promotes cerebellar granule cell exit from the EGL.
AB - In the cerebellum, the mRNAs for neurotrophin-3 (NT-3) and its high-affinity
tyrosine kinase receptor trkC are expressed by both the differentiated granule
cells of the internal granule cell layer (IGL) and their precursors in the
external germinal layer (EGL). We have investigated the effects of chronic
application of exogenous NT-3 in vivo on cerebellar granule cell genesis and
differentiation. NT-3 was applied to the posterior surface of the rat cerebellum
from P6 onwards using Elvax implants. At P10 the EGL of cerebellar lobules VII
and VIII was significantly reduced in thickness in NT-3 implanted rats when
compared with controls. Immunocytochemical analysis of the EGL using antibodies
to proliferating cell nuclear antigen (PCNA) revealed that the number of
postmitotic, premigratory (PCNA-immunonegative) granule cell precursors was
preferentially reduced in the NT-3 implanted rats. In situ DNA fragmentation
labelling confirmed that this was not accompanied by increased cell death in the
EGL. These results suggest that NT-3 promotes the differentiation of postmitotic,
premigratory granule cell precursors, accelerating cell exit from the EGL.
PMID- 9758171
TI - Cells in laminae III and IV of the rat spinal cord which possess the neurokinin-1
receptor receive monosynaptic input from myelinated primary afferents.
AB - We have previously demonstrated that neurons which have cell bodies in laminae
III or IV of the rat spinal cord, dendrites that enter the superficial laminae
and which possess the neurokinin-1 receptor receive a major synaptic input from
substance P-containing primary afferent axons. In this study we set out to
determine whether these cells also receive monosynaptic input from myelinated
primary afferents by using transganglionic transport of the B subunit of cholera
toxin to identify the central terminals of myelinated afferents from the sciatic
nerve. Dual-immunofluorescence and confocal microscopy revealed apparent contacts
between labelled primary afferent terminals and all of the neurokinin-1 receptor
immunoreactive cells examined, although these contacts were much less numerous
than those which the cells receive from substance P-containing primary afferents.
By using a combined confocal and electron microscopic technique we were able to
confirm that synapses were present at some of the contacts between primary
afferents and neurokinin-1 receptor-immunoreactive neurons. These results suggest
that cells of this type will have wide-dynamic range receptive fields, but with a
relatively strong input from nociceptors.
PMID- 9758172
TI - Blockade of M2-like muscarinic receptors enhances long-term potentiation at
corticostriatal synapses.
AB - Acetylcholine (ACh) exerts a crucial role in learning and memory. The striatum
contains the highest concentration of this transmitter in the brain. This
structure expresses two different forms of synaptic plasticity, long-term
depression (LTD) and long-term potentiation (LTP), which might contribute to the
storage of motor skills and some cognitive processes. We have investigated the
role of M2-like muscarinic receptors in striatal LTP by utilizing intracellular
recordings in vitro from a rat corticostriatal slice preparation. Methoctramine
(250 nM), an antagonist of M2-like muscarinic receptors, enhanced striatal LTP
induced in the absence of external magnesium (Mg2+) by high-frequency stimulation
(HFS) of corticostriatal fibres. Methoctramine did not affect the amplitude of
excitatory postsynaptic potentials (EPSPs) when bath applied either before or
after the conditioning tetanus suggesting that a critical increase of ACh
concentrations is produced only during HFS. Methoctramine per se failed to
enhance the NMDA-mediated EPSPs recorded in the absence of external Mg2+ and in
the presence of 10 microM CNQX. Methoctramine antagonized the presynaptic
inhibitory action of neostigmine, an inhibitor of ACh-esterase, and oxotremorine,
an agonist of M2-like muscarinic receptors. These data indicate that the
activation of M2-like muscarinic receptors exerts a negative influence on
striatal LTP, probably by reducing the release of glutamate from corticostriatal
fibres and they suggest a complex modulatory effect of ACh in striatal synaptic
plasticity.
PMID- 9758174
TI - Calretinin expression as a critical component in the control of dentate gyrus
long-term potentiation induction in mice.
AB - We have recently reported that mice homozygous (Cr-/-) for a null mutation in the
calretinin gene have impaired long-term potentiation (LTP) induction in the
dentate gyrus (S. Schurmans et al. (1997) Proc. Natl. Acad. Sci. USA, 94, 10415
). Here, we investigated dentate LTP induction in mice heterozygous (Cr+/-) for
the same mutation. Despite the presence of calretinin in neurons of these mice,
although at reduced levels as compared with normal mice, LTP induction in dentate
gyrus was totally impaired. Spatial memory and learning were found unaffected in
Cr+/- mice, such as in Cr-/- mice. Altogether, our results suggest that
calretinin is a critical component in the control of dentate synaptic plasticity
in mice, and that levels of calretinin higher than those observed in Cr+/- mice
are required to induce LTP in this area. The possible mechanisms leading to the
absence of correlation between gene dosage and biological effects are discussed.
PMID- 9758173
TI - Expression of the GABA(A) receptor gamma 4-subunit gene: anatomical distribution
of the corresponding mRNA in the domestic chick forebrain and the effect of
imprinting training.
AB - The learning process of imprinting involves morphological, electrophysiological
and biochemical changes in a region of the chick (Gallus gallus domesticus)
forebrain known as the intermediate and medial part of the hyperstriatum ventrale
(IMHV). The alterations include increases in the mean length of postsynaptic
density profiles of axospinous synapses and the number of N-methyl-D-aspartate
(NMDA) receptor binding sites, and changes in spontaneous and evoked electrical
activity. Recent immunocytochemical and behavioural studies have suggested that
inhibitory GABAergic neurotransmission plays a role in learning. In this context,
it has previously been reported that a novel avian gamma-aminobutyric acid (GABA)
type A (GABA(A)) receptor gene, encoding the gamma4 subunit, is highly expressed
in the hyperstriatum ventrale. In this study, we have used in situ hybridization
to map, in detail, the expression of the gamma4-subunit gene in the chick brain,
and to assess the effect of imprinting training on the level of the corresponding
transcript. Our results reveal that the gamma4-subunit mRNA has a restricted
distribution, and demonstrate a highly significant, time-dependent effect of
training on its steady-state level. At 10 h but not at 5 h after training there
is a decrease (25-32%) in the amount of this transcript in parts of the medial
hyperstriatum ventrale, including the IMHV. A decrease (28-39%) is also seen in
certain visual and auditory pathway areas but no effect was observed in other
forebrain regions such as the hyperstriatum intercalatus superior (HIS). These
results suggest that imprinting training leads to a time-dependent down
regulation of GABAergic transmission, and raise the possibility that this down
regulation plays a role in learning.
PMID- 9758175
TI - Pediatric tonsillectomy with bipolar electrosurgical scissors.
AB - PURPOSE: The optimal technique for pediatric tonsillectomy remains a hotly
debated topic. The speed and superior hemostatic properties of electrosurgical
dissection must be weighed against the greater tissue preservation and more rapid
healing of cold dissection techniques. MATERIALS AND METHODS: We have used a new
surgical device, bipolar electrosurgical scissors, in 30 consecutive pediatric
tonsillectomies. This instrument provides mechanical cutting with or without
simultaneous bipolar electrocoagulation. RESULTS: The average surgical time was 6
minutes. There was no intraoperative blood loss. There were no immediate or late
post-tonsillectomy hemorrhages. All tonsillar fossae were completely healed at 2
week follow-up. CONCLUSION: Bipolar electrosurgical scissors provide the best
properties of both cold dissection and electrosurgical tonsillectomy without
increasing surgical time or cost.
PMID- 9758176
TI - Hyoid bone syndrome and its treatment with nonsteroidal anti-inflammatory drugs.
AB - PURPOSE: Nonspecific cervical pain is a common complaint in primary ear, nose,
and throat clinic patients. In some cases, hyoid bone syndrome has been
recognized as the cause of the complaint. Our study describes this common but
unrecognized syndrome and suggests a treatment with nonsteroidal anti
inflammatory drugs (NSAIDs), a method of treatment not previously reported for
this syndrome. PATIENTS AND METHODS: Patients with suspected hyoid bone syndrome
(38) were treated with oral NSAIDs and/or with an NSAID ointment for topical
application. RESULTS: Symptomatic relief was obtained in 66% of our patients and
in 71% of the patients treated by NSAID tablets. Symptomatic relief was obtained
in 91% of the patients with symptom durations of less than 6 weeks. CONCLUSION:
We recommend a course of NSAID therapy as the first method of treatment for this
syndrome before treatment with invasive procedures, especially for patients with
symptom durations of less than 6 weeks. Better recognition of the hyoid bone
syndrome will result in a more effective treatment and will avoid an unnecessary
investigation.
PMID- 9758177
TI - Bacteria in the middle ear and nasopharynx during tympanostomy tube insertion.
AB - PURPOSE: To evaluate the efficacy of nasopharyngeal cultures in identifying
pathogens in middle-ear effusions as an alternative to cultures obtained through
tympanocentesis. MATERIALS AND METHODS: The study population consisted of 203
children with middle-ear effusions at the time of placement of tympanostomy tubes
for recurrent otitis media or persistent otitis media with effusion. Isolates
from the nasopharynx were compared with those from the middle ear to determine
sensitivity, specificity, and predictive values for each of the three main
pathogens. RESULTS: The predominant bacterial isolates from both ear and
nasopharynx were Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus
influenzae. Eighty-one percent (42% highly, 39% relatively) S pneumoniae
nasopharyngeal isolates were resistant to penicillin. The negative predictive
value of the nasopharyngeal cultures was at least 97% for each of these
predominant bacteria. CONCLUSION: This study supports the conclusion that
tympanocentesis is the most useful means of identifying pathogens in otitis
media.
PMID- 9758178
TI - Comparison between cartilage and soft tissue ear piercing complications.
AB - PURPOSE: Despite growing interest in cosmetic piercing, a detailed evaluation of
associated medical complications is lacking. MATERIALS AND METHODS: A
questionnaire addressing ear, nose, and other body parts piercing was anonymously
presented to 1,000 nurses at a major Midwestern teaching hospital, and responses
were obtained from 552. RESULTS: One hundred sixty (35%) of the 452 nurses who
had an ear pierced reported a complication. Three hundred fifty-five (30%) of the
1,200 total pierced sites developed complications that included minor infection
(77%), allergic reaction (43%), keloid (2.5%), and traumatic tear (2.5%). The
complication rate from piercing through cartilage (32%) was not significantly
different from that found when piercing through soft tissue (29%). The type of
complications experienced differed in frequency between cartilage and soft
tissue, with minor infection being more prevalent in cartilage piercing (30% v
21%; P < .10) and allergic reaction found more frequently in soft tissue
piercings (13% v 4%; P < .025). CONCLUSION: This study identifies a low
prevalence of major complications (<1%) and a relatively high prevalence of minor
complications (30%) associated with ear piercing. The expected increase in
complications and morbidity of piercing through cartilage was not found in this
study.
PMID- 9758179
TI - Elderly man presenting with asymptomatic hypercalcemia.
PMID- 9758180
TI - Eagle's syndrome: a review.
PMID- 9758181
TI - Polymorphous low-grade adenocarcinoma of the parotid gland.
PMID- 9758182
TI - Testicular carcinoma metastatic to the neck.
AB - PURPOSE: To show that a supraclavicular neck mass may be indicative of metastatic
testicular carcinoma and to offer further insight into the treatment of residual
neck disease. METHOD: We report six cases of testicular carcinoma metastatic to
the neck. All were initially treated with radiation, chemotherapy, or a
combination of both depending on histological type. RESULTS: Neck masses
persisted despite primary therapy. Three patients underwent subsequent modified
neck dissection and remained free of disease; three others received nonsurgical
forms of adjuvant therapy and ultimately died of their cancer. CONCLUSION:
Metastatic testicular carcinoma may manifest as a supraclavicular neck mass and
must therefore be considered in the differential diagnosis of a mass in this
region. Surgical resection is indicated in the management of neck masses that
persist after cytoreductive chemotherapy to remove residual foci of disease and
potential source of spread.
PMID- 9758184
TI - Nasopharyngeal carcinoma in two young brothers and its relationship with Epstein
Barr virus.
PMID- 9758183
TI - Merkel cell carcinoma of the external auditory canal invading the intracranial
compartment.
AB - PURPOSE: To report an unusual case of an intracranial extension of Merkel cell
carcinoma originating in the external ear canal and causing neurological
deficits. CASE REPORT: An 86-year-old woman, with a 16-month history of an
external auditory canal mass, presented with hemiparesis, facial paralysis, and
obtundation. Radiographic images showed an intracranial mass extending into the
petrous bone. METHOD: The patient had a craniotomy for intracranial tumor
resection with concurrent mastoidectomy for facial nerve decompression and
obtundation and hemiparesis were resolved. Residual tumor was subsequently
treated with adjuvant radiation therapy, and facial nerve function consequently
improved. CONCLUSION: Merkel cell tumors rarely invade the intracranial
compartments. Residual tumor and neurological deficits may respond to adjuvant
radiation therapy.
PMID- 9758185
TI - Symptomatic presentation of an enlarged, ossified triticeal cartilage.
PMID- 9758186
TI - Ectopic thyroid gland simulating a submandibular tumor.
PMID- 9758188
TI - Development of interpersonal communication.
PMID- 9758187
TI - Traumatic myositis ossificans of the levator scapulae muscle.
PMID- 9758189
TI - Class size and the quality of educational outcomes.
PMID- 9758190
TI - Routes from research to clinical practice in child psychiatry: retrospect and
prospect.
AB - The last 40 years has seen a virtual revolution in both medical research and
medical practice. Child psychiatry has been part of that revolution. The
situation in the 1950s is briefly noted and seven examples are used to illustrate
how causal research in the past has led to changes in clinical practice. The
areas used as examples comprise: autism, hyperactivity/attention deficit
syndromes, conduct disorders, depressive conditions, genetic research, organic
brain dysfunction, and psychosocial risk processes. Prospects for the future with
respect to the impact of research on clinical practice are discussed in relation
to molecular genetics, environmental risks, cognitive and affective processing of
experiences, links across the lifespan, and functional brain imaging. Attention
is drawn to implications for training as well as for practice.
PMID- 9758191
TI - The Emanuel Miller Memorial Lecture 1997. Change and continuity in the
development of children with autism.
AB - The developmental approach to childhood psychopathology identifies deviations
from typical patterns of development and stability of individual characteristics
over time, and precursors in early life of later functions. The application of
this approach to the social, communicative, and cognitive development of children
with autism is discussed. Results from a longitudinal study of children with
autism and other developmental disorders are described, indicating that children
with autism have stable deficits in joint attention, representational play, and
responsiveness to the emotions of others, and that early variations in these
abilities are important for concurrent and subsequent language development and
for peer engagement many years later.
PMID- 9758192
TI - Information processing deficits associated with developmental coordination
disorder: a meta-analysis of research findings.
AB - A meta-analysis was conducted to identify information processing factors that
characterise children with Developmental Coordination Disorder (DCD). A total of
50 studies yielded 374 effect sizes based on 983 DCD and 987 control children. A
mild generalised performance deficit was indicated, since motor-impaired children
were inferior on almost all measures of information processing. There were,
however, several areas where their deficiencies were more pronounced. The
greatest deficiency was in visual-spatial processing. This was evident regardless
of whether or not the tasks involved a motor component. Most other deficiencies
were in the small-to-moderate range and included kinaesthetic and cross-modal
processing. The findings support the notion that perceptual problems,
particularly in the visual modality, are associated with difficulties in motor
coordination.
PMID- 9758193
TI - Inattention, impulsivity, and hyperactivity from preschool to school age:
performance of hard-to-manage boys on laboratory measures.
AB - Boys identified as hard-to-manage at age 4 and age-matched controls were assessed
on laboratory measures of inattention, impulsivity, and hyperactivity at ages 4,
6, and 9. Hard-to-manage boys still exhibited some behavioral difficulties at age
9, but were not more inattentive or impulsive than controls. Boys with Attention
Deficit Disorder (ADD) at age 9 showed performance deficits in each symptom
related domain relative to problem boys without ADD and controls. However, hard
to-manage problem boys with and without ADD did not differ on most earlier
measures of inattention, impulsivity, and hyperactivity, suggesting that symptoms
specific to ADD emerged more clearly between ages 6 and 9.
PMID- 9758194
TI - Language, social cognitive processing, and behavioral characteristics of
psychiatrically disturbed children with previously identified and unsuspected
language impairments.
AB - This study examined characteristics of social cognitive processing, psychiatric
disorder, and behavioral ratings of 380 children aged 7 to 14 years who had been
referred consecutively for child psychiatric services with identified and
unsuspected language impairments and with normally developing language. The
results indicated that children with language impairments generally exhibited
greater deficits in social cognitive processing, and particularly emotion
decoding and social problem solving, than children who have language that is
developing normally. Differences in psychiatric diagnosis and behavior problems
were observed only between children with previously identified language
impairments and children with normally developing language; children with
previously identified language impairments were more likely to be diagnosed as
having Attention Deficit Hyperactivity Disorder (ADHD) and to be rated by both
parents and teachers as having more severe attentional problems. In addition,
teachers rated them as more socially withdrawn. The results suggest that it is
important to incorporate measures of both social cognition and language
functioning routinely into clinical assessment, something that currently is
rarely done.
PMID- 9758195
TI - Language, achievement, and cognitive processing in psychiatrically disturbed
children with previously identified and unsuspected language impairments.
AB - This study examined the language, achievement, and cognitive characteristics of
380 children, aged 7 to 14 years, consecutively referred to child psychiatric
services. Among those children referred solely for psychiatric problems, 40% had
a language impairment that had never been suspected. Children with previously
identified and unsuspected language impairments were similar with respect to
receptive and expressive language and on measures of cognitive processing.
Although both groups of children with language impairments exhibited poorer
academic achievement than children with normal language, children with previously
identified language impairments had the lowest achievement. The milder
achievement problems of children with unsuspected language impairment may explain
why their problems had not been suspected. Both the clinical and theoretical
implications of the findings are discussed. Heightened awareness concerning the
high frequency of language impairment and other cognitive processing problems in
children referred for psychiatric assessment and treatment should lead to more
systematic examination of language functioning and evaluation of the impact of
language and communication functioning on therapeutic outcomes.
PMID- 9758196
TI - Development of the Children's Communication Checklist (CCC): a method for
assessing qualitative aspects of communicative impairment in children.
AB - The Children's Communication Checklist (CCC) was developed to assess aspects of
communicative impairment that are not adequately evaluated by contemporary
standardised language tests. These are predominantly pragmatic abnormalities seen
in social communication, although other qualitative aspects of speech and
language were also included. Some items covering social relationships and
restricted interests were incorporated, so that the relationship between
pragmatic difficulties and other characteristics of pervasive developmental
disorders could be explored. Checklist ratings were obtained for 76 children aged
7 to 9 years, all of whom had received special education for language impairment.
In 71 cases, 2 raters (usually a teacher and speech-language therapist)
independently completed the checklist, making it possible to establish inter
rater reliability. From an initial pool of 93 items, 70 items, grouped into 9
scales, were retained. Five of the subscales were concerned with pragmatic
aspects of communication. A composite pragmatic impairment scale formed from
these subscales had inter-rater reliability and internal consistency of around
.80. This composite discriminated between children with a school diagnosis of
semantic-pragmatic disorder and those with other types of specific language
impairment (SLI). The majority of children with pragmatic language impairments
did not have any evidence of restricted interests or significant difficulties in
the domains of social relationships.
PMID- 9758197
TI - Are there subgroups within the autistic spectrum? A cluster analysis of a group
of children with autistic spectrum disorders.
AB - Comprehensive data on the developmental history and current behaviours of a large
sample of high-functioning individuals with diagnoses of autism, Asperger's
syndrome, or other related disorder were collected via parent interviews. This
provided the basis for a taxonomic analysis to search for subgroups. Most
participants also completed theory of mind tasks. Three clusters or subgroups
were obtained; these differed on theory of mind performance and on verbal
abilities. Although subgroups were identified which bore some relationship to
clinical differentiation of autistic, Asperger syndrome, and Pervasive
Developmental Disorder Not Otherwise Specified (PDD-NOS) cases, the nature of the
differences between them appeared strongly related to ability variables.
Examination of the kinds of behaviours that differentiated the groups suggested
that a spectrum of autistic disorders on which children differ primarily in term
of degrees of social and cognitive impairments could explain the findings.
PMID- 9758199
TI - Diagnostic rules for children with PDD-NOS and multiple complex developmental
disorder.
AB - This study was designed to examine the classification performance of diagnostic
rules for pervasive developmental disorder not otherwise specified (PDD-NOS) and
multiple complex developmental disorder (McDD), with clinical diagnosis as the
gold standard. McDD is an heuristic concept of a developmental disorder
characterised by social impairments, affective dysregulation, and thought
disturbance. Detailed information on the symptoms, reliably extracted from the
charts of 103 children with PDD-NOS and McDD, 32 with autistic disorder, and 96
with non-PDD disorders, was used to determine the presence of the DSM-IV criteria
of autistic disorder and the criteria of McDD. A scoring rule for PDD-NOS based
on a short set of seven DSM-IV criteria with a cut-off point of three items and
one social interaction item set as mandatory had the best balance between high
sensitivity and high specificity. The most effective and simple rule based on
McDD criteria had a cut-off of three items, out of six items of anxieties and
thought disturbance.
PMID- 9758198
TI - The development of theory of mind in deaf children.
AB - Deaf children aged 4 to 16 years were given a false-belief test of theory of
mind. Although the children experienced difficulty with the test, relative to
hearing children, confirming a report by Peterson and Siegal (1995), performance
was age-related, with a significantly higher proportion of 13- to 16-year-olds
passing the test. It was concluded that deaf children raised in a spoken language
environment show a developmental delay in theory of mind acquisition. This delay
is consistent with the assumption that their early opportunities for learning
about mental states are relatively restricted and that the normal development of
theory of mind is dependent upon such opportunities.
PMID- 9758200
TI - Sociometric classification methods in school peer groups: a comparative
investigation.
AB - The categorical consequences and psychometric properties of different sociometric
classification methods were evaluated. Children aged 9 to 12 years (N = 254)
completed three sociometric questionnaires and a peer assessment measure on two
occasions 5 weeks apart. The sociometric data were analysed using 13 different
methods. Analysis of kappa values indicated relatively poor agreement across
methods on subject classification. Temporal stability of the classifications was
also poor. Assessment of construct validity involved analysis of the peer
assessment items, using MANOVA to test hypotheses based on ideas from social
exchange theory. Cross-sex rating biases and difficulties with the neglected and
controversial classifications are discussed as indicating a need for the
application of theoretically based approaches which consider features of the peer
group social system and a need for caution in selecting methods for clinical use.
PMID- 9758201
TI - The relationship between endothelins and eicosanoids in the vasculature.
PMID- 9758202
TI - Dietary borage oil alters plasma, hepatic and vascular tissue fatty acid
composition in spontaneously hypertensive rats.
AB - Dietary borage oil rich in gamma-linolenic acid (GLA) has been shown to lower
blood pressure in Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR). A
potential mechanism for this effect may be attributed to changes in metabolism of
GLA to dihomogamma-linolenic (DGLA) and arachidonic acids (AA). We investigated
the effects of dietary borage oil on fatty acid composition in the plasma, liver
and vascular tissue in WKY and SHR. The diet significantly increased the levels
of omega-6 polyunsaturated fatty acids. GLA and DGLA levels in the plasma, liver,
aorta and renal artery tissues increased in SHR (P < 0.001) and WKY (P < 0.001).
AA levels were also increased in both plasma and liver of SHR (P < 0.05) and WKY
(P < 0.05) fed the borage oil enriched diet. The results demonstrate that dietary
borage oil produces marked changes in the metabolism of GLA which may contribute
to its blood pressure lowering effect in WKY and SHR.
PMID- 9758203
TI - Effective long-term inhibition of thromboxane production but not of serotonin
release in patients with coronary heart disease by 30 mg/d acetylsalicylic acid
dosage.
AB - Efficacy of aspirin (Acetylsalicylic acid, ASA) antiaggregatory prevention was
demonstrated in a series of clinical trials. The recommended ASA doses decreased
gradually and doses 50-30 mg ASA/d are intensively studied at the present time. A
group of 42 patients with coronary heart disease was evaluated: (1) Basal TXB2
production during spontaneous blood clotting was 360 +/- 37.6 ng/ml; (2) Two
initial doses were tested: while 200 mg ASA inhibited, during spontaneous blood
clotting, median TXB2 production by 99.9% (serum TXB2 concentration 1.35 ng/ml),
30 mg ASA median inhibition was just 42.0% (serum TXB2 151 ng/ml); (3) 30 mg
ASA/d maintenance dose was evaluated for 3 months. The median TXB2 production
inhibition was 98.5% (serum TXB2 3.75 ng/ml, first month) and 94.0% (serum TXB2
14.2 ng/ml, third month); (4) Four patients did not respond sufficiently, because
of noncompliance verified by the determination of salicyluric acid urinary
excretion, the lower limit of excretion being <3 micromol/2 h; (5) Both initial
and maintenance ASA dose decreased metabolic TXA2 endproducts in urine; (6) 5HT
platelet release did not decrease; (7) Potential changes of 5HT metabolic
elimination were excluded by the simultaneous determination of 5
hydroxyindoleacetic acid (5HIAA). In conclusion, 200 mg initial dose and 30 mg
ASA/d maintenance dose are suggested to be maximally inhibitory for TXB2
production without influence on 5HT release.
PMID- 9758205
TI - Diet can manipulate the metabolism of EPA and GLA in erythrocyte membrane and
plasma.
AB - The effect of diet on the metabolism of eicosapentaenoic acid (EPA) and
gammalinolenic acid (GLA) was investigated in two groups of African Green Vervet
monkeys fed either a Western atherogenic diet (WAD; %E fat 43.5%; P:S 0.3; n=10)
or a high carbohydrate diet (HCD; %E fat 20.5%; P:S 3.4; n=10). Vervets within
each dietary treatment were supplemented with 300 mg/day with either an EPA
concentrate (50% as free fatty acid, n=5) or a GLA concentrate (70% as free fatty
acid, n=5) for 24 weeks, increasing the dose every 6 weeks to a maximum of 2400
mg/kg/day. Vervets in the WAD-Group consumed 433.7 mg/kg/day of EPA and those in
the HCD-Group 318.2 mg/kg/day of EPA, whereas 421 mg/kg/day of GLA was consumed
in the WAD Group and 340 mg/kg/day in the HCD Group during the last 6 weeks (week
18-24) of the supplementation period. The rate of disappearance of EPA and GLA
from plasma and erythrocyte memebrane (EMB) phospholipids were estimated for the
two diets after supplementation was stopped. The half-lives (t(1/2)) of EPA in
EMB phosphatidylcholine (PC) were estimated to be 34.6 days (WAD) and 22.6 days
(HCD), compared to 43.5 days (WAD) and 31.3 days (HCD) in EMB
phosphatidylethanolamine (PE). In plasma cholesteryl ester (CE) t(1/2) was 23.5
days (WAD) compared to 14.1 days (HCD), and in plasma triacylglycerol (TAG) 17.4
days (WAD) compared to 9.4 days (HCD). Although accurate estimation of the GLA
t(1/2) was difficult to assess due to the low tissue levels (probably due to
rapid conversion to DGLA), the disappearance rates of GLA from EMB and plasma
also suggested a faster metabolic rate in those animals consuming a HCD compared
to a WAD. EPA also disappeared faster from EMB PC than from EMB PE. Disappearance
of EPA from plasma TAG was also faster than from plasma CE, probably reflecting
their relative turnover and metabolic rates. During supplementation, EPA
substituted linoleic acid (C18:2 n-6), arachidonic acid (C20:4 n-6), and GLA
(C18:3 n-6). This was reversed when supplementation was stopped. Plasma total
cholesterol (TC) levels decreased by 17.06 +/- 17.67% in animals consuming the
HCD with EPA as supplement, whereas in those consuming the WAD, plasma TC levels
increased with 21.78 +/- 28.23% during the supplementation period. The delay of
EPA and GLA disappearance from EMB and plasma in animals consuming a WAD,
strongly suggests that metabolism of EPA and GLA is modulated by diet. Such a
modulation could cause an accumulation of plasma TC levels that could explain the
contradictory results reported by previous studies.
PMID- 9758204
TI - Effects of inhibitors of nitric oxide synthase on isolated uteri of fasting rats.
AB - The effects of inhibitors of nitric oxide synthase on the glucose metabolism of
uteri isolated from 4-day underfed rats were studied. In control rats receiving
normal feeding, the addition of indomethacin (5 x 10(-6) M); acetyl salicylic
acid (10(-4) M); 400 microM of N(G)methyl-L-arginine, (L-NMMA) or 400 microM of
sodium nitroprusside (SNP), does not modify the production of 14CO2 from U14C
glucose. On the contrary, in fasted rat uteri, indomethacin increases glucose
oxidation significantly, while acetyl salicylic acid does not alter it. Also, the
addition of L-NMMA has no effect. In another group of experiments, in the
preparations containing indomethacin of uteri isolated from underfed rats, the
addition of L-NMMA significantly changes the effect of indomethacin. Another
inhibitor of nitric oxide synthase, N(omega)nitro-L-arginine methyl ester (L
NAME), or hemoglobin (2 microg ml(-1)) a nitric oxide scavenger have the same
effects while N(omega)nitro arginine-D-methyl ester (D-NAME) does not. However
(SNP), a nitric oxide donor, does not alter the production of 14CO2 in uteri
isolated from fasted rats. These results show that in underfed rats, indomethacin
increases glucose oxidation independently from its inhibiting effect on
cyclooxygenase. Specific inhibitors of nitric oxide synthase can reverse this
effect.
PMID- 9758206
TI - Incorporation of delta 5 desaturase substrate (dihomogammalinolenic acid, 20:3 n
6) and product (arachidonic acid 20:4 n-6) into rat liver cell nuclei.
AB - The incorporation of [1-(14)C]20:3 n-6 and its desaturation product, [1
(14)C]20:4 n-6 into nuclear lipids from rat liver cells were investigated during
in vitro delta5 desaturation. [1-(14)C]20:3 n-6 activated as 20:3 n-6-CoA by
nuclear long chain acyl-CoA synthetase was: (1) incorporated into nuclear lipids
mainly esterified to phospholipids and in a lesser proportion, to triglycerides
and diglycerides; and (2) desaturated to 20:4 n-6-CoA by the nuclear delta5
desaturase. The amount of [1-(14)C]20:4 n-6 acid synthesized in cell nuclei
increased along with time and was stimulated by the cytosol fraction. The major
proportion of 20:4 n-6 was found in phospholipids and in a lesser proportion it
remained as free fatty acids and was esterified to triglycerides and
diglycerides. 20:4 n-6-CoA was incorporated into nuclear lipids and hydrolyzed to
free fatty acid. These results indicate that liver cell nuclei possess the
necessary enzymes to incorporate the delta5 desaturase substrate (20:3 n-6) as
well as the product of desaturation (20:4 n-6) into nuclear TG, DG and PL
following an acyl-CoA dependent pathway.
PMID- 9758207
TI - Effects of PGE2 and of different synthetic PGE derivatives on the glycosylation
of pig gastric mucins.
AB - The glycosylation of pig gastric mucins, discharged in response to prostaglandin
(PG) E2 and to three synthetic PGE-derivatives (misoprostol, nocloprost,
rioprostil) was compared. After a 20 h culture period in the absence or presence
of 1 micromol/l of one of the PGs, mucins were isolated by gel chromatography and
their glycosylation characterized by their linkage to a panel of lectins. For all
tested PGs, a significantly increased lectin linkage to mucin glycoproteins of
high molecular weight was detected; no significant effects were observed for low
molecular weight glycoproteins. Within the stimulatory pattern, major effects
were found for the linkage of peanut agglutinin and soybean agglutinin,
suggesting predominant effects on the expression of galactose and N-acetyl
galactosamine. Only minor effects were found for sialic acid, mannose, N-acetyl
glucosamine and fucose expression, as evidenced by the linkage of Sambucus nigra
agglutinin, Concanavalin A, Datura stramonium agglutinin and Ulex europaeus I
agglutinin. All PGs exerted a similar stimulatory pattern. However, at the
indicated concentration, misoprostol (281 +/- 36% of control) rendered a
significantly higher overall effect than PGE2 (208 +/- 31%), whereas the
increases induced by nocloprost (237 +/- 35%) and rioprostil (202 +/- 35%) were
not significantly different from the PGE2 effects. These results, suggesting
similar stimulatory effects of PGE2 and of the tested synthetic PGs on
glycosylation of mucin oligosaccharides, discharged from mucous cells during an
in vitro culture, may, at least in part, explain clinical findings that during an
impairment of the endogenous PG synthesis, the tested synthetic PGs are effective
exogenous substitutes for endogenous E-type prostaglandins and act as anti-ulcer
drugs.
PMID- 9758208
TI - Systematic pharmacological approach to the characterization of NSAIDs.
AB - Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment
of inflammatory diseases. NSAIDs inhibit cyclooxygenase (COX), the rate limiting
enzyme responsible for the conversion of arachidonic acid into prostaglandins.
Recent studies have shown the existence of two isoforms of cyclooxygenase: COX-1,
now often referred to as the constitutive form, and COX-2, an inducible form
which is the major isoenzyme involved in prostaglandin synthesis in inflammation
and other pathological situations. Since inhibition of prostaglandin production
in tissues where they play a physiological role leads to important side effects,
a COX-2 preferential inhibitor would present therapeutical advantages. In the
present study, we evaluated the inhibitory properties of cyclooxygenase
inhibitors on human COX-1 and COX-2 using a heterologous expression system. We
investigated instantaneous inhibition and pre-incubation inhibition as well as
time recovery of cyclooxygenase activity assays with the aid of four NSAIDs:
mefenamic acid, indomethacin, aspirin and NS-398. Our results demonstrate that
instantaneous inhibition assays have little correlation with clinical results.
Inhibition assays using pre-incubation with the drugs tested, however, more
closely resemble the data from in vivo studies. Cyclooxygenase recovery assays
enabled better characterization of simple competitive inhibitors, competitive
reversible time-dependent inhibitors and irreversible time-dependent inhibitors.
The data illustrate the usefulness of our system in allowing a better
determination of the pharmacological characteristics of NSAIDs as well as
permitting a comparison among different drugs.
PMID- 9758209
TI - Interleukin-1 beta and dexamethasone regulate gene expression of prostaglandin H
synthase-2 via the NF-kB pathway in human amnion derived WISH cells.
AB - Interleukin-1beta (IL-1beta) stimulated PGE2 synthesis in human amnion derived
WISH cells, whereas dexamethasone blocked IL-1beta-mediated stimulation of PGE2
production. Sequence analysis of the 5'-flanking region of the human
prostaglandin H synthase-2 (PGHS-2) gene indicates two putative NF-kB binding
sites. Mutation of a single site or both sites resulted in significantly
decreased activity of the PGHS-2 promoter. IL-1beta treatment increased
significantly the native promoter activity and this increase was attenuated by
using the NF-kB-mutant promoter. Dexamethasone treatment also decreased the IL
1beta mediated stimulation of the PGHS-2 native promoter but not the NF-kB mutant
promoter. Furthermore, the involvement of the NF-kB was supported by
electrophoretic mobility shift assay which revealed an increased nuclear binding
of the NF-kB probe upon IL-1beta induction and a decreased nuclear binding of the
NF-kB probe upon dexamethasone pre-treatment. These results provide convincing
evidence that NF-kB may mediate the IL-1beta stimulation of PGHS-2 gene
expression as well as the dexamethasone inhibition of the IL-1beta induction
process in WISH cells.
PMID- 9758210
TI - Eicosanoid profile in cultured human pulmonary artery smooth muscle cells treated
with IL-1 beta and TNF alpha.
AB - Interleukin-1beta (IL-1beta) and tumor necrosis factor (TNF alpha) induce
prostanoid biosynthesis in vascular smooth muscle cells by promoting
cyclooxygenase (COX) expression, but little is known about the biosynthesis of
lipoxygenase (LPO) metabolites. We investigated the effects of human recombinant
IL-1beta and TNF alpha on the production of arachidonic acid (AA) metabolites by
high-performance liquid chromatography (HPLC). After being labelled with 3H-AA,
cultured human pulmonary artery smooth muscle cells (HPASMC) were incubated with
or without IL-1beta (200 U/ml) and TNF alpha (500 U/ml). The arachidonic acid
metabolites released from HPASMC were then analysed by HPLC. In control HPASMC, 6
keto-PGF1alpha and PGE2 were the principal metabolites of the COX pathway, while
5-HETE, LTC4 and D4 were the main products of the LPO pathway. HPASMC treated
with 200 U/ml of IL-1beta and 500 U/ml of TNF alpha produced more COX metabolites
such as 6-keto-PGF1alpha, thromboxane B2, PGF2alpha and PGE2 than control cells.
Significant increases in the production of LPO derivatives such as LTB4, C4, D4,
and 15-HETE were also found in IL-1beta-treated HPASMC. Although the release of
LPO products tended to increase in TNF alpha-treated cells, no significant change
was noted. Many AA metabolites including LTB4 are responsible for the
inflammatory process in vivo. AA metabolites produced by pulmonary artery smooth
muscle cells might play important roles in cytokine-mediated acute lung injury
and inflammation.
PMID- 9758211
TI - Use of a semi-automated, robotic radioimmunoassay to measure cAMP generated by
activation of DP-, EP2-, and IP-prostaglandin receptors in human ocular and other
cell types.
AB - The aim of these studies was to compare the effects of several prostaglandin
agonists on adenylyl cyclase activity in embryonic bovine tracheal (EBTr) cells,
transformed human nonpigmented ciliary epithelial (NPE) cells and National Cancer
Bank (NCB-20) cells. These cell types have been shown to express DP, EP2 and IP
prostaglandin (PG) receptors, respectively. Cyclic AMP (cAMP) generation was
measured by manual and semi-automated radioimmunoassay (RIA) techniques. ZK118182
(EC50 = 10-27 nM), PGE2 (EC50 = 21-27 nM) and PGI2 (EC50 = 3.5-4 nM) had the
highest potency at the DP, EP2 and IP receptors, respectively. A plot of potency
(EC50) values generated with both techniques showed a high degree of correlation
for all three receptors. These studies provide further characterization of
prostanoid receptor functional responses in three cell types and demonstrate the
advantages of a semi-automated RIA method for the analysis of the second
messenger cAMP.
PMID- 9758212
TI - Reciprocal up- and down-regulation of BDNF mRNA in tetanus toxin-induced
epileptic focus and inhibitory surround in cerebral cortex.
AB - Chronic focal epilepsy is associated with synaptic plasticity and growth of new
connections. Brain-derived neurotrophic factor (BDNF) is associated with each of
these processes in normal brain and shows acute up-regulation in models of
generalized epilepsy. Here, using an experimental model of focal epilepsy, we
show persistent up-regulation of BDNF mRNA, independent of that of other growth
factors, in association with the development and persistence of chronic seizures.
In situ hybridization histochemistry revealed that rats perfused within 2-3 days
after seizure onset had widespread increases in BDNF mRNA levels in the
neocortex. Rats perfused at later times, however, showed focal up-regulation of
BDNF mRNA at the injection site and down-regulation in a surrounding cortical
zone. Nerve growth factor and neurotrophin-3 mRNAs were not significantly
altered. These reciprocal changes in BDNF gene expression in the epileptic focus
and the cortical surround may contribute to plastic changes in epileptic neuronal
circuits that accompany the transition from acute to chronic epilepsy. BDNF down
regulation in the surround is likely to be associated with the inhibitory
surround that hampers seizure spread, but facilitates the persistence of a
chronic epileptic focus.
PMID- 9758213
TI - Cortical variability and asymmetry in normal aging and Alzheimer's disease.
AB - The onset of Alzheimer's disease (AD) is accompanied by a complex and distributed
pattern of neuroanatomic change, difficult to distinguish clinically from dynamic
alterations in normal aging. Extreme variations in the sulcal patterns of the
human cortex have made it difficult to identify diffuse and focal variations in
cortical structure in neurodegenerative disease. We report the first
comprehensive 3D statistical analysis of deep sulcal structure in vivo, in both
normal aging and dementia. High-resolution 3D T1-weighted fast SPGR (spoiled
GRASS) MRI volumes were acquired from 10 patients diagnosed with AD (NINCDS-ARDRA
criteria; age: 71.9 +/- 10.7 years) and 10 normal subjects matched for age (72.9
+/- 5.6 years), gender, educational level and handedness. Scans were digitally
transformed into Talairach stereotaxic space. To determine specific patterns of
cortical variation in dementia patients, 3D average and probabilistic maps of
primary deep sulci were developed for both normal and AD groups. Major sulci
(including supracallosal, cingulate, marginal, parieto-occipital, anterior and
posterior calcarine sulci, and Sylvian fissures) were modeled as complex systems
of 3D surfaces using a multi-resolution parametric mesh approach. Variations and
asymmetries in their extents, curvature, area and surface complexity were
evaluated. Three-dimensional maps of anatomic variability, structural asymmetry
and local atrophy indicated severe regionally selective fiber loss in AD. A
midsagittal area loss of 24.5% at the corpus callosum's posterior midbody (P <
0.025) matched increases in structural variability in corresponding temporo
parietal projection areas. Confidence limits on 3D cortical variation, visualized
in 3D, exhibited severe increases in AD from 2 to 4 mm at the callosum to a peak
SD of 19.6 mm at the posterior left Sylvian fissure. Normal Sylvian fissure
asymmetries (right higher than left; P < 0.0005), mapped for the first time in
three dimensions, were accentuated in AD (P < 0.0002), and were greater in AD
than in controls (P < 0.05). Severe AD-related increases in 3D variability and
asymmetry may reflect disease-related disruption of the commissural system
connecting bilateral temporal and parietal cortical zones, regions known to be at
risk of early metabolic dysfunction, perfusion deficits and selective neuronal
loss in AD.
PMID- 9758214
TI - View-invariant representations of familiar objects by neurons in the inferior
temporal visual cortex.
AB - A view-invariant representation of objects in the brain would have many
computational advantages. Here we describe a population of single neurons in the
temporal visual cortex (IT) that have view-invariant representations of familiar
objects. Ten real plastic objects were placed in the monkeys' home cages for a
period of time before neurophysiological experiments in which neuronal responses
were measured to four views of each object. The macaques performed a visual
fixation task, and had never been trained in object discrimination. The majority
of the visual neurons recorded were responsive to some views of some objects
and/or to the control stimuli, as would be expected from previous studies.
However, a small subset of these neurons were responsive to all views of one or
more of the objects, providing evidence that these neurons were coding for
objects, rather than simply for individual views or visual features within the
image. This result was confirmed by information theoretic analyses, which showed
that the neurons provided information about which object was being seen,
independently of the view. The coding scheme was shown to be sparse distributed,
with relatively independent information being provided by the different neurons.
Hypotheses about how these view-invariant cells are formed are described.
PMID- 9758215
TI - Nonlinear dynamics of 3 Hz spike-and-wave discharges recorded during typical
absence seizures in children.
AB - One-channel routine recordings of the scalp electroencephalogram (EEG) from
unmedicated children strictly classified as unprovoked typical (3 c/s) absence
seizures were selected. The dynamics of spike-and-wave discharges (SWD) were then
examined by means of autocorrelation, correlation dimension, averaged pointwise
dimension and largest Lyapunov exponent. For one EEG signal with pronounced spike
and-wave (SW) patterns, these measures were used complementary to a surrogate
data method, a nonlinear (SETAR) modeling approach, and a SW simulation procedure
providing five types of SW test signals. The SETAR model exhibited stationary SW
dynamics, visually very similar to the EEG target signal, and with clear
nonlinear structure. According to the results, the EEG episodes investigated
represent low-dimensional dynamics, possibly recorded during nonstationary
periods. Arguments that justify the assumption of deterministic chaos in our EEG
signals were not obtained with the current methods. From the results one may
conclude that two global oscillatory modes are present for the model, and three
modes are active during the EEG recording period.
PMID- 9758216
TI - Cerebral blood flow relationships associated with a difficult tone recognition
task in trained normal volunteers.
AB - Tone recognition is partially subserved by neural activity in the right frontal
and primary auditory cortices. First we determined the brain areas associated
with tone perception and recognition. This study then examined how regional
cerebral blood flow (rCBF) in these and other brain regions correlates with the
behavioral characteristics of a difficult tone recognition task. rCBF changes
were assessed using H2(15)O positron emission tomography. Subtraction procedures
were used to localize significant change regions and correlational analyses were
applied to determine how response times (RT) predicted rCBF patterns. Twelve
trained normal volunteers were studied in three conditions: REST, sensory motor
control (SMC) and decision (DEC). The SMC-REST contrast revealed bilateral
activation of primary auditory cortices, cerebellum and bilateral inferior
frontal gyri. DEC-SMC produced significant clusters in the right middle and
inferior frontal gyri, insula and claustrum; the anterior cingulate gyrus and
supplementary motor area; the left insula/claustrum; and the left cerebellum.
Correlational analyses, RT versus rCBF from DEC scans, showed a positive
correlation in right inferior and middle frontal cortex; rCBF in bilateral
auditory cortices and cerebellum exhibited significant negative correlations with
RT These changes suggest that neural activity in the right frontal, superior
temporal and cerebellar regions shifts back and forth in magnitude depending on
whether tone recognition RT is relatively fast or slow, during a difficult,
accurate assessment.
PMID- 9758217
TI - Constant and variable aspects of axonal phenotype in cerebral cortex.
AB - In order to determine to what extent the terminal arbors of phylogenetically and
functionally distant axons are constructed according to common rules, we have
compared visual callosal axons in cats (CCC axons) with thalamocortical axons to
the whisker representation in mice (MTC axons). Both similarities and differences
were found. Maximal order of branching, branching angles, topological
distribution of branches and boutons are similar for all axons, indicating strong
constraints in arbor formation. CCC and MTC axons are indistinguishable for total
arbor length and number of branches, although these parameters can vary across
individual axons of each group. MTC axons have longer and bouton-richer end
branches (the 'transmission compartment') while, in CCC axons, proximal,
boutonless branches (the 'conduction compartment') predominate. Therefore, the
two classes of axons appear to be specialized for performing different types of
operations, in agreement with the available electrophysiological data and
computer simulations. Differences in the length of branches were also observed
between MTC axons of normal and 'barrelless' mice, suggesting that this parameter
can be regulated by conditions at the terminal sites.
PMID- 9758218
TI - A neural model of binocular integration and rivalry based on the coordination of
action-potential timing in primary visual cortex.
AB - In normal vision, the inputs from the two eyes are integrated into a single
percept. When dissimilar images are presented to the two eyes, however, they
compete for perceptual dominance, so that one eye's view suppresses that of the
other. Recent evidence suggests that this phenomenon, known as binocular rivalry,
arises through competition between alternative stimulus interpretations in
extrastriate cortex. Because eye-specific information appears to be lost at this
stage, it remains unclear how the stimulus conditions that yield binocular
rivalry are distinguished from those that produce stable single vision. Using a
neural network that models the mammalian early visual system, I investigate here
the hypothesis that congruent and conflicting stimuli are distinguished by their
different effects on the relative timing of action potentials in primary visual
cortex (V1), where monocular inputs are first combined. In the model, congruent
stimulation of both eyes results in synchronization of discharges among binocular
neurons in V1. By contrast, conflicting stimulation of the two eyes results in
neuronal asynchrony in this area. This asynchrony then produces rivalrous
response suppression at later stages in the visual pathway. Synchronization of
firing in V1, however, prevents such competition, thereby ensuring non-rivalrous
responses. These novel effects of spike timing on competition emerge naturally
from the network dynamics. The results suggest that input-related differences in
relative spike timing at an early stage of visual processing may play an
important part in the phenomena both of binocular integration and rivalry;
furthermore, they indicate that the temporal patterning of cortical activity may
be a fundamental mechanism of selection among competing stimulus representations.
PMID- 9758219
TI - Selective neurokinin-1 receptor antagonists are anti-hyperalgesic in a model of
neuropathic pain in the guinea-pig.
AB - Neuropathic pain is poorly managed by conventional analgesic therapy, such as non
steroidal anti-inflammatory drugs and opiates. The development of animal models
of peripheral neural damage has aided in our understanding of the pathology and
pharmacology of neuropathic pain. This report is the first clear demonstration
using selective neurokinin-1 receptor antagonists of a potentially novel
therapeutic approach to the treatment of neuropathic pain resulting from
peripheral nerve damage in a guinea-pig model. The neurokinin-1 receptor
antagonists, SDZ NKT 343 and LY 303,870 significantly reduced mechanical
hyperalgesia following oral and intrathecal administration. (R,R)-SDZ NK T343,
the enantiomer of SDZ NKT 343 did not show anti-hyperalgesic activity. RPR
100,893 showed significant anti-hyperalgesic activity only following intrathecal
administration suggesting poor absorption or low level penetration of the blood
brain barrier. These results imply that neurokinin-1 receptor antagonists offer a
new class of anti-hyperalgesic drugs with a largely central site of action in
neuropathic pain.
PMID- 9758220
TI - Evidence for P2X3 receptors in the developing rat brain.
AB - P2X receptor-mediated responses to the ATP analogue, alpha,beta-methylene ATP, in
rat brain cannot be accounted for by the receptor proteins known to be present.
Such experiments are often performed on cells from neonates and, since
differential developmental regulation of P2X1 and P2X2 receptor messenger RNAs
has already been demonstrated, this is likely to be the case for other P2X
receptors. This study was designed to address the possible existence of
alpha,beta-methylene ATP-sensitive P2X3 receptors in rat brains of various ages
using a P2X3 receptor-selective antibody. P2X3 receptor protein was found in
discrete regions of the embryonic (E16) and neonatal rat brain (P7 and P14) but
was not detectable in adult animals. This is the first demonstration of the
presence of these receptors in brains from various ages of rat and the
differential expression of these receptors in neonates may account for some
reported electrophysiological responses to alpha,beta-methylene ATP.
PMID- 9758221
TI - Dynamic clamp study of Ih modulation of burst firing and delta oscillations in
thalamocortical neurons in vitro.
AB - The dynamic clamp technique was used in thalamocortical neurons of the rat and
cat dorsal lateral geniculate nucleus in vitro to investigate the effects of the
hyperpolarization-activated cation current, Ih, and of its neuromodulation on
burst firing and delta oscillations. Specific block of endogenous Ih using 4-(N
ethyl-N-phenylamino)-1,2-dimethyl-6-(methylamino)pyridinium chloride (ZD7288)
(300 microM) abolished the depolarizing "sag" response to negative current steps,
markedly increased the latency and shortened the duration of the low-threshold
Ca2+ potentials, and decreased the number of action potentials in the burst
evoked by the low-threshold Ca2+ potential. Subsequent introduction of artificial
Ih using the dynamic clamp re-instated the "sag" and all the original properties
of the low-threshold Ca2+ potential. In the absence of ZD7288, introduction of
artificial outward Ih with the intention of abolishing endogenous Ih removed the
depolarizing "sag" and produced similar effects on the low-threshold Ca2+
potentials as those observed during the pharmacological block of Ih. Application
of ZD7288 to thalamocortical neurons displaying delta oscillations led to a
reduction in the voltage range of their existence or to a complete cessation of
this behaviour. A subsequent introduction of artificial Ih re-enabled the
generation of delta oscillations. In the presence of ZD7288, physiologically
relevant positive shifts in the voltage-dependence of artificial Ih increased the
amplitude and duration of the low-threshold Ca2+ potential and increased the
likelihood of delta oscillations while negative shifts had opposite effects.
These results highlight the important difference between the dependence of burst
firing and oscillations on membrane potential and their dependence on the
properties of Ih, and demonstrate that the modulation by Ih of low-threshold Ca2+
potentials and burst firing in thalamocortical neurons, as well as the ability of
these neurons to generate delta oscillations, is more elaborate than previously
described.
PMID- 9758222
TI - The neurosteroid pregnenolone sulfate infused into the nucleus basalis increases
both acetylcholine release in the frontal cortex or amygdala and spatial memory.
AB - The effects of an infusion (5 ng) of the neurosteroid pregnenolone sulfate into
the nucleus basalis magnocellularis on acetylcholine release in the
frontoparietal cortex and basolateral amygdala were evaluated during the 130 min
post-injection in male Sprague-Dawley rats using in vivo microdialysis coupled
"on line" with high performance liquid chromatography detection. One week later,
the same animals were tested for spatial memory after another infusion of
pregnenolone sulfate (5 ng) into the nucleus basalis. Results show that
pregnenolone sulfate enhanced acetylcholine release by more than 50% of baseline
concentrations in the two structures relative to a control injection. The
duration of this effect was longer in cortex (130 min) than in amygdala (30 min).
Furthermore, pregnenolone sulfate improved memory performance in a task based
upon spatial recognition of a familiar environment. A significant positive
correlation (r=0.49) was found between the recognition score in the spatial
memory test and the levels of acetylcholine release in the frontoparietal cortex
but not in the basolateral amygdala. Therefore, our results suggest that the
nucleus basalis magnocellularis-cortical pathway could be in part responsible for
the promnesic effect of pregnenolone sulfate. This neurosteroid acts as a
negative modulator of the GABA(A) receptor complex and positively modulates the N
methyl-D-aspartate receptor, possibly resulting in a global stimulatory effect on
central cholinergic neurotransmission.
PMID- 9758223
TI - Insulin-like growth factor-1 ameliorates age-related behavioral deficits.
AB - Insulin-like growth factor-1 has been found to be involved in the regulation of
several aspects of brain metabolism, neural transmission, neural growth and
differentiation. Because decreased insulin-like growth factor-1 and/or its
receptors are likely to contribute to age-related abnormalities in behavior, the
strategy of replacing this protein is one potential therapeutic alternative. The
present study was designed to assess whether cognitive deficits with ageing may
be partially overcome by increasing the availability of insulin-like growth
factor-1 in the brain. Fischer-344 x Brown Norway hybrid (F1) male rats of two
ages (four-months-old and 32-months-old) were preoperatively trained in
behavioral tasks and subsequently implanted with osmotic minipumps to infuse the
insulin-like growth factor-1 (23.5 microg/pump) or a vehicle, i.c.v. Animals were
retested at two weeks and four weeks after surgery. Insulin-like growth factor-1
improved working memory in the repeated acquisition task and in the object
recognition task. An improvement was also observed in the place discrimination
task, which assesses reference memory. Insulin-like growth factor-1 had no effect
on sensorimotor skills nor exploration, but mildly reversed some age-related
deficits in emotionality. These data indicate a potentially important role for
insulin-like growth factor-1 in the reversal of age-related behavioral
impairments in rodents.
PMID- 9758225
TI - Changes in neurotransmitter release in the main olfactory bulb following an
olfactory conditioning procedure in mice.
AB - Olfactory learning is associated with substantial neural changes at the level of
the accessory and main olfactory bulb, during both pheromonal learning in mated
mice and lamb odour recognition in post partum sheep. These forms of learning
occur during "sensitive periods" and an important question is whether similar
neural changes occur in the olfactory bulb at other times. We used a classical
conditioning procedure to establish an olfactory discrimination in adult mice and
then measured changes in neurotransmitter levels in the main olfactory bulb in
response to the presentation of the conditioned odours. Presentation of the
conditioned, but not the non-conditioned, odour resulted in significant increases
in the levels of certain transmitters, including glutamate from the mitral/tufted
cells, GABA from the granule and periglomerular cells and noradrenaline from the
centrifugal projection from the locus coeruleus. Overall, there was a decrease in
the ratio of excitatory to inhibitory neurotransmitters in the olfactory bulb in
response to the conditioned, but not the non-conditioned odour. Moreover, the
magnitude of the decrease in this ratio was correlated with the level of
behavioural response to the conditioned odour. These findings support the
hypothesis that changes in the gain of the reciprocal synapses between
mitral/tufted neurons and their inhibitory interneurons are a general feature of
olfactory learning.
PMID- 9758226
TI - In vitro long-term potentiation of electrotonic responses of goldfish mauthner
cells is accompanied by ultrastructural changes at afferent mixed synapses.
AB - The potentiated afferent mixed synapses of the Mauthner cells of fry and adult
goldfish in stumps of the medulla oblongata incubated long-term in vitro were
studied by electrophysiological and electron microscopic methods. It was shown
that brief high-frequency stimulation of posterior branches of the eighth nerve
induced a long-term potentiation of electrotonic transmission at large and small
mixed club endings. It was about 135% upon subthreshold stimulation and about
200% upon suprathreshold stimulation. The ultrastructural analysis of ultrathin
sections of potentiated mixed synaptic endings revealed an increase in the
dimensions of desmosome-like contacts which was proportional to the degree of
potentiation, about 135% or 200%, depending on the type of stimulation. The
dimensions of gap junctions remained unchanged. The dimensions of active zones at
potentiated synapses were reduced two-fold as compared with their unpotentiated
counterparts, irrespective of the type of stimulation. Considering that desmosome
like contacts consist predominantly of F-actin, a molecule which possesses
electroconductivity, it can be assumed that this cytoskeletal protein is involved
in the process of potentiation. The increase in the synapse electrical
conductivity can be mediated either directly, by shunting the synaptic junction
with polymer actin filaments in the region of desmosome-like contacts, or
indirectly, via the interaction of actin with gap junction connections situated
nearby.
PMID- 9758224
TI - Magnocellular vasopressinergic neurons in explant cultures are rescued from cell
death by ciliary neurotrophic factor and leukemia inhibiting factor.
AB - Selective death of magnocellular vasopressinergic neurons in the hypothalamus has
been reported in cases of hereditary and idiopathic diabetes insipidus and after
experimental lesions of the hypothalamo-neurohypophyseal pathway. To identify
trophic factors that promote survival of these neurons, an in vitro model system
was established in which organotypic cultures of the rat hypothalamic
paraventricular nucleus were maintained in chemically-defined medium. We observe
that the majority of magnocellular vasopressinergic neurons die in these
cultures, while other cell populations such as corticotrophin-releasing factor
producing parvicellular and oxytocin producing magnocellular cells retain a well
preserved cytoarchitectonic organization. Degenerating vasopressinergic cells
exhibit morphological signs of apoptosis and stained positively when analysed by
the terminal deoxynucleotidyl transferase biotinylated dUTP nick end-labelling
assay. Partial survival of vasopressinergic neurons occurred after co-culturing
the paraventricular nucleus with neurohypophyseal explants, indicating that
target-derived factors may be required for the survival of these neurons. Cell
survival is dramatically increased by the administration of ciliary neurotrophic
factor and leukemia inhibiting factor, but not by interleukin 6 or the members of
the neurotrophin family. Reverse transcription-polymerase chain reaction followed
by Southern analysis shows the presence of ciliary neurotrophic factor messenger
RNA in the neurohypophysis. Thus, endogenous ciliary neurotrophic factor and
leukemia inhibiting factor, produced by neurohypophyseal cells may function as a
physiological survival factor for neurosecretory vasopressinergic neurons.
PMID- 9758227
TI - Ultrastructural analysis reveals avoidance conditioning to induce a transient
increase in hippocampal dentate spine density in the 6 hour post-training period
of consolidation.
AB - Concepts underlying memory consolidation invoke change in synapse structure and
function. Such concepts relate to change in connectivity pattern enabled by
increased synapse number, change in synaptic configuration resulting from
overproduction and selective pruning, or structural change in synapse
transmission zones. This study undertook the unbiased estimation of learning
associated change in dendritic spine number on granule cells in the hippocampal
dentate gyrus. Rats were trained to acquire a passive avoidance response after
which spine number in the mid-molecular layer of the dorsal dentate gyrus were
estimated at increasing post-training times. This showed there to be an increase
in spine density with time after training which was initiated at 3 h, and maximal
at 6 h. The increase at this latter time was not detected in passive control
animals. At 72 h post-training spine density was seen to return to basal levels.
These results are consistent with the various models for synapse connectivity
change in memory formation whether they relate to altered number or connectivity
pattern.
PMID- 9758229
TI - The subcellular and cellular distribution of G protein-coupled receptor kinase 2
in rat brain.
AB - G protein-coupled receptor kinase 2 has been found to phosphorylate and thus
regulate the activity of several G protein-coupled receptors implicated in
neuronal signalling pathways. Although this kinase was initially described as a
soluble protein, our laboratory has recently found that a significant amount of G
protein-coupled receptor kinase 2 is associated with microsomal membranes in
liver and different types of cultured cells. In the present report we show that
high G protein-coupled receptor kinase 2 specific activity and protein levels are
present in microsomal fractions of rat brain homogenates. On the other hand,
immunochemical detection using a new antibody raised against the N-terminus of
the kinase revealed a specific and widely distributed staining in different areas
of the central nervous system, and the association of G protein-coupled receptor
kinase 2 with intracellular structures in nervous cells. Our results further
suggest that this receptor kinase may be involved in the modulation of G protein
coupled receptor-mediated neurotransmission and that association with microsomal
membranes may play a role in G protein-coupled receptor kinase 2 functions in the
brain.
PMID- 9758228
TI - Allosteric regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate
receptors by thiocyanate and cyclothiazide at a common modulatory site distinct
from that of 2,3-benzodiazepines.
AB - Allosteric regulators of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate
(AMPA) receptors include 2,3-benzodiazepines such as GYKI 52466 and GYKI 53655
and the chaotropic anion thiocyanate that inhibit, and benzothiadiazines such as
cyclothiazide that potentiate AMPA receptor currents. Here we sought to determine
whether the allosteric regulators modulate AMPA receptors at a common or distinct
allosteric sites by comparing their actions on AMPA- and kainate-evoked currents
in cultured rat hippocampal neurons and Xenopus oocytes expressing recombinant
AMPA receptor subunits. GYKI 52466 and thiocyanate blocked AMPA-evoked currents
in a concentration-dependent manner (IC50 values, 8.2 microM and 1.1 mM,
respectively); in contrast, kainate-evoked currents were blocked by GYKI 52466,
but were potentiated by high concentrations of thiocyanate (> or = 3 mM).
Thiocyanate enhanced the rate of desensitization and slowed recovery from
desensitization of AMPA-evoked currents, whereas GYKI 52466 failed to affect
desensitization. Among neurons in the hippocampal cultures, there was cell-to
cell variability in the sensitivity to block of AMPA-evoked currents by
thiocyanate that was correlated with the degree of potentiation by cyclothiazide.
Moreover, cyclothiazide caused a parallel rightward shift in the concentration
response curve for thiocyanate block, and slowed the onset of thiocyanate block
to a rate that was similar to that of cyclothiazide dissociation. Together, these
observations suggest that thiocyanate and cyclothiazide act at non-distinct
allosteric sites. GYKI 52466 blocked AMPA receptor responses to a similar extent,
irrespective of the degree of cyclothiazide potentiation. Moreover, the kinetics
of GYKI 53655 block in the presence of cyclothiazide were not consistent with a
competitive interaction. As is the case for cyclothiazide, SCN- exhibited greater
affinity for flip than for flop AMPA receptor splice variants. In particular,
GluR1flip/GluR2flip was especially sensitive to thiocyanate block. We conclude
that thiocyanate, a flip-preferring allosteric modulator like cyclothiazide,
appears to act by enhancing desensitization at a site that may overlap the site
where cyclothiazide reduces desensitization, whereas 2,3-benzodiazepines act at a
distinct site and the block does not involve a modification of desensitization.
PMID- 9758230
TI - Oral Dyskinesias and striatal lesions in rats after long-term co-treatment with
haloperidol and 3-nitropropionic acid.
AB - The pathophysiologic basis of tardive dyskinesia remains unclear. It has been
proposed that tardive dyskinesia may be a result of excitotoxic neurodegeneration
in the striatum caused by a neuroleptic-induced increase in striatal glutamate
release and impaired energy metabolism. To investigate this hypothesis,
haloperidol decanoate (38 mg/kg/four weeks intramuscularly) and the succinate
dehydrogenase inhibitor 3-nitropropionic acid (8 mg/kg/day via subcutaneous
osmotic mini-pumps), were administered alone or together for 16 weeks to four
months-old rats. Control rats received sesame oil intramuscularly and had empty
plastic tubes subcutaneously. Vacuous chewing movements, a putative analogue to
human tardive dyskinesia, were recorded during and after drug treatment.
Haloperidol alone, 3-nitropropionic acid alone, and 3-nitropropionic
acid+haloperidol treatments induced an increase in vacuous chewing movements.
However, vacuous chewing movements were more pronounced and appeared earlier in
rats treated with 3-nitropropionic acid+haloperidol. After drug withdrawal,
increases in vacuous chewing movements persisted for 16 weeks in the haloperidol
alone and 3-nitropropionic acid+haloperidol group and for four weeks in the 3
nitropropionic acid alone group. Brains from each group were analysed for
histopathological alterations. Bilateral striatal lesions were present only in
rats with high levels of vacuous chewing movements in the 3-nitropropionic
acid+haloperidol-treated rats. Nerve cell depletion and astrogliosis were
prominent histopathologic features. There was selective neuronal sparing of both
large- and medium-sized aspiny striatal neurons. These results suggest that mild
mitochondrial impairment in combination with neuroleptics results in striatal
excitotoxic neurodegeneration which may underlie the development of persistent
vacuous chewing movements in rats and possibly irreversible tardive dyskinesia in
humans.
PMID- 9758231
TI - Characterization of the mechanism of action of tachykinins in rat striatal
cholinergic interneurons.
AB - The mechanism by which substance P depolarizes cholinergic interneurons in the
rat striatum was studied using whole-cell recording techniques. In all cases the
effects of substance P were mimicked by the neurokinin1 receptor agonist [Sar9,
Met(O2)11] substance P and were antagonized by the neurokinin1 receptor
antagonist SR140333. [Sar9, Met(O2)11] substance P was found to depolarize
cholinergic interneurons by the induction of a calcium-activated inward current
at -60 mV. This inward current was irreversibly potentiated by photolysis of
caged GTPgammaS within neurons implicating the involvement of a G-protein. The
[Sar9, Met(O2)11] substance P-induced inward current was inhibited by the
phospholipase C inhibitor U-73122, and by the inclusion of the inositol-1,4,5
triphosphate receptor antagonist heparin in the electrode solution. These
findings suggest that neurokinin1 receptors depolarize cholinergic interneurons
in the rat striatum primarily through a phosphoinositide signalling pathway.
PMID- 9758232
TI - Postsynaptic nicotinic receptors on dopaminergic neurons in the substantia nigra
pars compacta of the rat.
AB - Previous studies have shown that application of nicotinic agonists in the
substantia nigra pars compacta increases the firing rate of dopaminergic neurons.
We have used intracellular recordings to show that the response of these neurons
to nicotine is postsynaptic, since it persists in the presence of low-calcium
buffer containing tetrodotoxin. Burst firing in the presence of nicotine was not
observed. The presence of postsynaptic nicotinic receptors was confirmed by
immunohistochemical localization of the alpha4 nicotinic receptor subunit on
dendrites in the substantia nigra pars compacta. The majority of tyrosine
hydroxylase-immunopositive neurons in the substantia nigra pars compacta were
also immunopositive for the alpha4 subunit. Immunohistochemical localization of
the alpha4 and beta2 subunits in adjacent brain sections produced similar
patterns of staining. Electron micrographs clearly indicated the presence of
alpha4 subunit at postsynaptic densities. The predominant role of nicotinic
receptors in the central nervous system has been suggested to be the presynaptic
modulation of neurotransmitter release [McGehee D. S. and Role L. W. (1995) A.
Rev. Physiol. 57, 521-546]. Although several postsynaptic nicotinic responses
have also been reported in the literature, it is unclear as to whether the
postsynaptic nicotinic receptors mediating responses to exogenously applied
agonists are involved in synaptic transmission. From our electrophysiological and
immunohistochemical results, we conclude that alpha4-containing nicotinic
receptors are found at synapses on dopaminergic neurons. These synapses are
similar to the cholinergic synapses described at these neurons, suggesting that
nicotinic receptors are important in modulating the excitability of dopaminergic
neurons by direct synaptic transmission.
PMID- 9758233
TI - Localization of 5-hydroxytryptamine1A and 5-hydroxytryptamine7 receptors in
rabbit ocular and brain tissues.
AB - Serotonin is thought to play a physiological role in various tissues of the
rabbit eye, yet little is known about the relative distribution of the different
serotonin receptors. Demonstration of the receptor subtypes present in the
various ocular tissues is essential in order to understand the function of
serotonin in the eye. Using a combination of in situ hybridization
histochemistry, in vitro receptor autoradiography and polymerase chain reaction
studies, we have explored the distribution of the 5-hydroxytryptamine1A and 5
hydroxytryptamine7 receptors in the rabbit eye. As these receptors have not been
sequenced in the rabbit, we initially established the suitability of the
oligonucleotide probes by analysis of brain tissue. The distributions of 5
hydroxytryptamine1A and 5-hydroxytryptamine7 receptor messenger RNAs in rabbit
brain correlated well with those in other species, confirming the specificity of
the probes for detection of the messenger RNAs in rabbit tissues. In the eye, the
expression of 5-hydroxytryptamine1A receptors appears to be restricted to the
epithelial cell layer of the ciliary processes, although very low levels may
appear in the retina. In contrast, the expression of 5-hydroxytryptamine7
receptor messenger RNA is more widespread with positive signals evident in the
ciliary processes, retina and iris. The results confirm the existence of 5
hydroxytryptamine1A receptors in the ciliary body and their localization in the
ciliary epithelium supports the hypothesis that they are involved in the
secretion of aqueous humour. Unexpectedly, there was little evidence to support
the idea that 5-hydroxytryptamine1A receptors are present in the retina and iris
sphincter. However, the subsequent finding of 5-hydroxytryptamine7 receptor
messenger RNA in the retina and iris may explain the apparent absence of 5
hydroxytryptamine1A receptors in these tissues. The presence of both 5
hydroxytryptamine1A and 5-hydroxytryptamine7 receptors in the ciliary processes
may account for the complex intraocular pressure response of the rabbit to
serotonin.
PMID- 9758234
TI - Immunolabelling of the rat intestinal tract with antibodies specific to the long
form of the 5-hydroxytryptamine3 receptor.
AB - The mouse 5-hydroxytryptamine3 (5-HT3) type of serotonin receptors is expressed
as two forms, 5-HT3R-A(L) and 5-HT3R-A(S), generated by alternative splicing of
its primary transcript, that differ by a stretch of six amino acids in the second
intracellular loop domain. Because this six-amino acid region contains a putative
phosphorylation site that may be important for the function and/or regulation of
5HT3R-A(L) receptor, specifically, we developed polyclonal antibodies as
appropriate tools for studies relevant to this question. Antibodies against a 20
amino acid peptide corresponding to the sequence of 5-HT3R-A(L) at the level of
this six-amino acid region were obtained as soon as one month after injection of
this synthetic peptide to rabbits. Immunocytochemistry with these antibodies led
to a strong positive labelling of plasma membrane, reticulum and Golgi apparatus
of COS-7 cells expressing cloned murine 5-HT3R-A(L), whereas COS-7 cells
expressing similar levels of 5-HT3R-A(S) exhibited only a very weak labelling.
Immunoblots of fusion proteins combining glutathion-S-transferase and the second
cytoplasmic loop of 5-HT3R-A(L) or 5-HT3R-A(S) revealed a c. 20-fold selectivity
of the antibodies for the first, long form, as evaluated by densitometric
analysis of enhanced chemiluminescence detection. Similarly, immunoblots of COS-7
cells transfected with cloned 5-HT3 receptors showed that the anti-peptide
antibodies detected a band at 53,000 mol. wt only in cells transfected with 5
HT3R-A(L). Under optimal conditions, antibodies immunoprecipitated 52% of 5-HT3R
A(L), but only 11% of 5-HT3R-A(S), solubilized from COS-7 cells transfected with
the respective encoding plasmids. In the rat, no immunoautoradiographic labelling
by the anti-peptide antibodies could be detected in brain structures which had
previously been described to express preferentially a short form of the 5-HT3
receptor. In contrast, a strong immunolabelling was found in the intestinal
mucosa, especially in the rat fetus (at the 17th embryonic day), suggesting the
possible participation of the 5-HT3R-A(L) isoform in the development of this
tissue. These results show that specific antibodies are useful tools for the
visualization of the least abundant 5-HT3 receptor isoform in rat tissue.
PMID- 9758235
TI - Opsin localization and rhodopsin photochemistry in a transgenic mouse model of
retinitis pigmentosa.
AB - The VPP mouse is a transgenic strain carrying three mutations (P23H, V20G, P27L)
near the N-terminus of opsin, the apoprotein of rhodopsin, the rod photopigment.
These animals exhibit a slowly progressive degeneration of the rod
photoreceptors, and concomitant changes in retinal function that mimic those seen
in humans with autosomal dominant retinitis pigmentosa resulting from a point
mutation (P23H) in opsin. In the present study we attempted to determine whether
the disease process prevents the translocation of mutant opsin to the rod outer
segments of transgenic mice, and whether it affects the photochemical properties
of the rhodopsin present within their rod outer segments. Immunocytochemistry
with a monoclonal antibody against a region of the C-terminus that recognizes
epitopes common to both normal and mutant opsin (monoclonal antibody-1D4), and a
polyclonal antibody that reacts preferentially with the mutant opsin (anti-VPP),
were used to identify the opsin present in the rods of three-week-old VPP mice
and normal littermates. Absorbance spectra, photosensitivity, and regeneration
kinetics of rhodopsin in rod outer segment disc membranes were analysed by
spectrophotometry. Western blot analysis with anti-VPP antibody indicated the
specific binding of this antibody to the mutant opsin. Immunolocalization with
monoclonal antibody-1D4 and anti-VPP antibodies suggested a normal translocation
of the mutant protein to the outer segments. Aside from a small disparity in the
absorbance spectra of rhodopsin obtained from normal and VPP retinas, there were
no significant differences in either the ability of opsin to bind 11-cis retinal
chromophore, or in the photic sensitivity of rhodopsin. The results indicate that
mutant opsin is translated and incorporated into the rod outer segment disc
membranes of VPP mice, and that the photochemical properties of rhodopsin in the
rods of VPP retinas are similar to those of rhodopsin in normal retinas.
PMID- 9758237
TI - The cost implications of obesity for health care and society.
AB - The prevalence of obesity (body mass index (BMI) > 30 kg/m2) has been rising
consistently in recent decades. Obesity is among the key promoters of a number of
other highly prevalent and often fatal diseases. These characteristics make
obesity one of the major cost drivers in Western health-care systems. For
Germany, the direct costs of obesity itself are estimated to be about 850 million
DM. Taking into account all attributable co-morbidities, the direct costs are
estimated to be between 8.6-11.5 billion DM. If the indirect costs are also
included in the calculations, these costs will multiply still further. There is a
need for clinical trials in a primary care setting, in order to determine the
impact of drug treatment (for example, sibutramine) on the treatment of obesity,
the quality of life and the benefits of this treatment by means of a cost-benefit
analysis (CBA) and cost-utility analysis (CUA).
PMID- 9758238
TI - Emerging management strategies for obesity.
AB - Management strategies for obesity, which include drug therapy, are emerging as a
consequence of the increasing recognition of the medical seriousness of obesity.
Obesity requires appropriate and effective management by suitably trained members
of a multidisciplinary team, with treatment programmes putting equal importance
on weight reduction and its maintenance. Such programmes must also take into
account the reduction in risk from co-morbid conditions after modest weight loss
(5-10% of initial body weight). The use of an anti-obesity drug may be justified
for patients at risk from obesity where dietary methods, including exercise and
behaviour modification, have failed to achieve a 10% reduction in initial body
weight after at least three months from the start of the episode of managed care.
Anti-obesity drugs must be prescribed in an appropriate setting, with patients
being reviewed on a regular basis. Essential elements for managed weight loss
include, a printed management programme, appropriate equipment, specified and
realistic weight-loss goals, documentation of individual patient's health risks,
and clearly defined follow-up procedures with explicit guidelines for the use of
drugs and notification of other doctors involved in the patient's care. The
process of drug treatment necessitates a system of regular medical audit. Many
health-care professionals and lay persons remain sceptical about the scientific
value of anti-obesity drugs. The emergence of increasingly specific and effective
agents underlines the importance of ensuring appropriate use for patients at risk
from obesity.
PMID- 9758236
TI - Calcium channel subtypes responsible for voltage-gated intracellular calcium
elevations in embryonic rat motoneurons.
AB - The central role of electrical activity and Ca2+ influx in motoneuron development
raises important questions about the regulation of Ca2+ signalling induced by
voltage-dependent Ca2+ influx. In the purified embryonic rat motoneuron
preparation, we recorded barium currents through voltage-activated Ca2+ channels
using the whole-cell configuration of the patch-clamp technique. We found that
motoneurons express at least four types of high-voltage-activated Ca2+ channels,
based on their kinetics, voltage-dependences and pharmacological properties. Of
the sustained Ca2+ current activated at 0 mV from a holding potential of -100 mV,
approximately 45% was omega-conotoxin-GVIA (1 microM) sensitive, 25% was omega
agatoxin-IVA (30 nM) sensitive and 20% was nitrendipine (250 nM) sensitive. The
residual current, after applying these three antagonists, was an inactivating
current that differs from classical T-type Ca2+ currents. Based on this
pharmacology, changes in intracellular free Ca2+ concentrations were then
monitored by Fura 2 digital imaging microspectrofluorimetry. Upon K+
depolarization, the intracellular Ca2+ transient induced by the activation of
each type of Ca2+ channel appeared to be quantitatively proportional to their
Ca2+ influx. The existence of a calcium-induced calcium release mechanism through
activation of caffeine-, ryanodine-sensitive intracellular stores was then
investigated. High doses of caffeine and low doses of ryanodine failed to
increase intracellular free calcium concentrations and low concentrations of
caffeine and high concentrations of ryanodine did not affect K+-induced
intracellular free calcium concentration transients indicating both the absence
of Ca2+-gated Ca2+-release channels and of a Ca2+-induced Ca2+ release mechanism.
Together, these data provide evidence that embryonic motoneurons express multiple
Ca2+ channels that function as important regulators of intracellular Ca2+
signalling and may be involved in their development.
PMID- 9758239
TI - Advances in pharmacotherapy for obesity.
AB - Anorectic drugs are increasingly being used in obesity to induce and/or maintain
weight loss. We have focused on the development of metabolic enhancers. These
compounds increase energy expenditure, which is important because weight loss is
associated with metabolic re-adjustment to reduce energy output. Thus, metabolic
enhancers ensure that energy expenditure is maintained when food intake is
reduced. Beta3-adrenoceptor agonists are thermogenic agents that increase energy
output by stimulating heat generation. Early selective beta3-agonists were
effective in producing weight loss in obese rats, but were largely ineffective in
humans. In addition, many interacted with other types of beta receptor to produce
side-effects. The development of a Chinese hamster ovary cell (CHO) transfection
system, using the human beta3-adrenoceptor gene, resulted in potential new
selective human beta3-agonists being identified. However, the in vitro activity
of these agents does not necessarily reflect their action in vivo, due to the
presence of other receptor types and G proteins in the target cells, and
interactions between them. The characterization of a selective beta3-antagonist,
SR59230A, has allowed us to examine beta3-agonist activity in different
experimental systems. The CHO transfection system has been used to show that
SR59230A is effective in blocking agonist activity against both the rat
adrenoceptor, and three human beta3-receptor isoforms. In addition, SR59230A
shows competitive inhibition of agonist activity in both rat and human model
systems. This antagonist may therefore provide a pharmacological tool for the
functional study of by newly identified beta3-receptor agonists.
PMID- 9758240
TI - Sibutramine: a novel anti-obesity drug. A review of the pharmacological evidence
to differentiate it from d-amphetamine and d-fenfluramine.
AB - Sibutramine (BTS 54 524; N-[1-[1-(4-chlorophenyl)cyclobutyl]-3-methylbutyl]-N,N
dimethylamine hydrochloride monohydrate) is a novel 5-HT (serotonin) and
noradrenaline reuptake inhibitor (SNRI) anti-obesity drug. Sibutramine reduces
the food intake of rodents and this effect is partially or completely reversed by
pretreating with 5-HT or noradrenaline antagonists, indicating that both
neurotransmitters are involved in sibutramine's hypophagic effect. In addition,
fluoxetine and nisoxetine, which are selective reuptake inhibitors of 5-HT and
noradrenaline, respectively, have no effect on food intake when given alone, but
they profoundly inhibit food intake when given in combination (equivalent to the
actions of the SNRI, sibutramine), demonstrating a synergistic interaction of
those two monoamines in the control of ingestive behaviour. Sibutramine reduces
food intake by enhancing the physiological response of post-ingestive satiety.
This reduction of food intake is a CNS-mediated effect because it is induced by
intracerebroventricular injection of sibutramine's potently active secondary and
primary amine metabolites (BTS 54 354 and BTS 54 505). Sibutramine increases
energy expenditure (thermogenesis) in rats. Once again, whilst fluoxetine and
nisoxetine have no thermogenic effect when given alone, the combination of these
two selective monoamine reuptake inhibitors profoundly enhances thermogenesis,
demonstrating a synergistic interaction of 5-HT and noradrenaline
neurotransmission in the regulation of energy expenditure. Sibutramine-induced
thermogenesis is abolished by administration of a high non-selective dose of
atenolol or ICI 118,551 which blocks beta3-adrenoceptors in addition to beta1-
and beta2-adrenoceptors, but not by a low dose of atenolol or ICI 118,551 which
blocks beta1- and beta2-adrenoceptors, respectively. Glucose utilization studies
demonstrate that sibutramine-induced thermogenesis is mediated via selective
sympathetic activation of brown adipose tissue, and it is a centrally mediated
effect because it is prevented by pretreating the animals with the ganglionic
blocker, chlorisondamine. The SNRI mode of action of sibutramine is clearly
differentiated from those of the two major classes of anti-obesity drugs, viz,
the 5-HT releasing agents, for example, fenfluramine and dexfenfluramine, and the
noradrenaline + dopamine-releasing agents, for example, dexamphetamine. In the
case of the 5-HT-releasing agents, this mechanism has been linked in animal
studies to profound and prolonged depletion and dysfunction of CNS 5-HT neurons.
With noradrenaline + dopamine-releasing agents, it is the enhancement of central
dopaminergic function which is believed to be responsible for their stimulant,
rewarding and reinforcing properties and it is their releasing mechanism which
makes them such powerful psychostimulant drugs of abuse. By utilizing
noradrenaline and 5-HT for its anti-obesity effects, sibutramine is
differentiated from other weight-reducing drugs which act through either 5-HT
alone or noradrenaline + dopamine. In addition, sibutramine is further
differentiated because it enhances monoamine function by reuptake inhibition,
rather than by monoamine release.
PMID- 9758241
TI - Sibutramine and energy balance.
AB - Obesity develops from a combination of low energy expenditure and increased
energy intake. The current treatment strategy aims at reducing energy intake by a
low-fat, high-complex-carbohydrate diet and increasing energy expenditure by
increased physical activity. In a major proportion of obese patients, however,
this treatment is ineffective and does not produce a satisfactory long-term
result. Among the risk factors for weight gain and for an unsuccessful diet
induced weight loss in obese patients is a low metabolic rate, which can be
attributed in part to a low sympathetic nervous system (SNS) activity. The low
SNS activity may also have an adverse effect on appetite control. Pharmacological
enhancement of the SNS may have a role in the normalization of the autonomic
control of the disturbed energy balance in obesity. In animal studies,
sibutramine causes a negative fat balance and weight loss, by a dual mechanism of
action. Sibutramine enhances satiety by a combined noradrenergic and serotonergic
effect, thus decreasing food intake. In addition, sibutramine stimulates
thermogenesis by activating the SNS. Recent studies have demonstrated that
sibutramine also enhances satiety, stimulates thermogenesis and diminishes the
weight-loss induced decline in energy expenditure in humans, so the dual effect
on energy balance seems to be responsible for the efficient fat loss and weight
maintenance found in clinical trials on obese patients. In conclusion,
sibutramine can contribute to normalization of the disturbed energy balance in
obesity, by enhancing satiety and by the stimulation of energy expenditure.
PMID- 9758242
TI - Sibutramine and fat distribution: is there a role for pharmacotherapy in
abdominal/visceral fat reduction?
AB - Visceral adiposity has a strong and independent association with obesity and its
related co-morbidities, particularly metabolic complications such as
cardiovascular disease and type II diabetes. Waist circumference and waist-to-hip
ratio (WHR) are both secondary indicators of visceral obesity. This paper
examines the effect of sibutramine, a new serotonin and noradrenaline re-uptake
inhibitor, on weight reduction and changes in fat distribution. A meta-analysis
of four long-term, placebo-controlled, double-blind studies showed significantly
greater mean decreases in waist circumference in sibutramine-treated subjects
compared with placebo (P < 0.001). Similar results were seen for WHR, with 15 mg
sibutramine daily producing a significant reduction of 0.02 compared with placebo
(P < 0.02). Changes in fat distribution have been examined using computerised
tomography (CT) scans as part of the Sibutramine Trial of Obesity Reduction and
Maintenance (STORM). Preliminary results showed a mean weight loss from baseline
of 11.2 +/- 6.3 kg after 6 months of 10 mg sibutramine treatment. Decreases in
total abdominal fat (18%), total subcutaneous fat (17%) and total visceral fat
(22%) were observed, and there was a significant increase in the subcutaneous-to
visceral fat ratio (P = 0.04). These changes in fat levels and distribution were
associated with improvements in related risk factors such as fasting blood
glucose and insulin levels, and blood pressure. In conclusion, sibutramine
produces statistically and clinically significant decreases in waist
circumference and WHR, and preferentially reduces visceral fat levels.
PMID- 9758243
TI - Cerebral metabolic response to hypoglycemia in severe intrauterine growth
retarded rat pups.
AB - This study was to examine the effects of hypoglycemia on the brain metabolism of
severe intrauterine growth retardation (IUGR) rat pups. IUGR pups were produced
by ligating one of the uterine arteries of the dams. The pups on the opposite
uterine horn were used as the control. They were delivered by cesarean section on
day 21 and received regular insulin 5 units/kg or equivalent volume of normal
saline at 40 min of age. The plasma glucose, lactate, blood gas values and brain
glucose, lactate, ATP contents were determined at 5 and 100 min of age. The IUGR
pups had higher plasma and brain lactate concentrations than the control
throughout the study period. They had lower plasma glucose, oxygen and pH values,
brain glucose and ATP contents than control at 5 min of age. Despite insulin
induced hypoglycemia, brain ATP contents of the IUGR recovered to normal levels
at 100 min of age when the oxygenation and pH improved. These data indicate that
the brain energy metabolism of IUGR rat pups was suppressed by asphyxia and
hypoglycemia. However, even in the continuing presence of hypoglycemia, brain
energy metabolism returned to normal. The recovery is probably related to better
oxygenation and utilization of alternative energy fuels, such as lactate.
PMID- 9758244
TI - Prognosis following prenatal diagnosis of heart malformations.
AB - Our objective was to document the prognosis of cases with fetal heart
malformations (FHM). Forty-two fetuses assessed both in a regional fetal medicine
and paediatric cardiology unit were classified prenatally into isolated FHM or
those associated with extra-cardiac structural or karyotypic anomalies (ECA) and
this classification was not changed subsequently (analogous to an intention to
treat analysis). The end points studied included chromosomal abnormality,
pregnancy outcome and follow-up at one year of age. FHM were isolated in 16 (38%)
and associated with ECA in 26 (62%) of cases. The karyotypic abnormality rate was
8/42 (19%) overall and 8/26 (31%) in ECA cases. The pregnancy outcome included
termination of pregnancy in 19 (45%), intrauterine death of two (5%) and live
birth in 21 (50%). 12/16 (75%) of isolated FHM cases were live born compared with
9/26 (35%) of ECA cases (P < 0.03). Of the isolated FHM live born babies, 8/12
(67%) were alive at the end of the first year and seven of these were growing
normally and did not require cardiac medication. However, a considerable
proportion of their first year was spent in hospital (median 8%, interquartile
range 5-10). Only one of nine ECA live born cases was alive but with poor growth
and dependence on cardiac drugs at one year. These data confirm previous findings
in prenatal diagnosis series that the prognosis for FHM is worse than that
reported in studies of congenital heart disease at birth and is strongly
dependent upon the presence of ECA. In their absence, outcome is better than
previously published. Counselling must take place only after full fetal medicine
assessment and should be based upon prenatal data.
PMID- 9758245
TI - In situ morphometric analysis of the coronary arterial growth in perinatal rats.
AB - The perinatal changes in the diameters of left and right coronary arteries in
rats were studied using the rapid whole body freezing technique. The main portion
of the left coronary artery and left anterior descending and circumflex branches
rapidly increased in diameter after birth as well as ascending aorta. The ratios
of the diameters of the left coronary artery and anterior descending branch to
the diameter of ascending aorta increased significantly after 4 days of age. In
contrast, there were no significant changes in the diameter of the right coronary
artery from the fetus to the 8-day-old pups and the ratio of the right coronary
artery to the ascending aorta significantly decreased after birth. We report here
that the left coronary artery in rats increases in diameter more rapidly than the
right coronary artery in the early newborn period.
PMID- 9758246
TI - Sleep state changes associated with cerebral blood volume changes in healthy term
newborn infants.
AB - In order to assess the possible effects of sleep states on cerebral haemodynamics
in healthy term infants, we measured cerebral oxyhaemoglobin, deoxyhaemoglobin
and total haemoglobin concentration using near infrared spectroscopy. Thirty
seven sleep state changes in seventeen infants (gestational age: 37 to 41 4/7
weeks), aged between two and eight days were continuously registrated during 1-3
h. Transcutaneous PaO2, PaCO2, arterial O2 saturation and heart rate were
simultaneously recorded and sleep states were clinically defined. There was a
close relationship between sleep state changes and changes in total cerebral
haemoglobin concentration, which increased from active to quiet sleep and
decreased from quiet to active sleep. Changes in total cerebral haemoglobin were
due, in the most part, to changes in the cerebral oxyhaemoglobin concentration.
In conclusion, sleep states influence the cerebral haemoglobin concentration.
Studies on cerebral haemodynamics should take sleep state into account in term
newborn infants.
PMID- 9758247
TI - Detection of cytokines and cytomegalovirus DNA in serum as test for congenital
infection.
AB - Maternal serum samples at 10 and 22 weeks of gestational age and cord blood
samples were available from six cases of asymptomatic congenital human
cytomegalovirus (HCMV) infection. Meaningful rises of serum IgG-antibody titers
by ELISA occurred in three cases. Serum interferon (IFN)-gamma activity was
detected in all six cases. Serum cell free soluble interleukin-2 receptor (sIL
2R) activity rose above the normal range (145-519 U/ml) in one IgG and IgM
antibody-positive and three IgG antibody-positive woman. Serum levels of sIL-2R
and IFN-gamma were not elevated in anti-HCMV antibody-negative healthy pregnant
women. No HCMV IE DNA was detected by PCR in the serum of any of the pregnant
women. HCMV DNA was detected in the serum of one of six infants with asymptomatic
congenital HCMV infection. Assessment of the changes of serum cytokines such as
sIL-2R and IFN-gamma in HCMV antibody-positive pregnant women may be useful for
the prenatal diagnosis of active HCMV infection during pregnancy.
PMID- 9758248
TI - The effect of thermal stimulation on the heart-rate variability in neonates.
AB - Thermoregulation in humans can be divided into three broad mechanisms of control,
namely: shivering, sweating and vasomotor activity. Previous investigations
suggested the presence of an autonomic rhythm, originating in the central nervous
system, possibly related to thermal vasomotor control and directly affecting
heart rate by reflex changes in cardiac sympathetic and parasympathetic activity.
The objective of the present work was to study the maturation process of the
thermoregulatory system in newborns. We used peripheral thermal entrainment and
focused on the reflections of vasomotor control in the heart-rate (HR) power
spectrum (PS). The study included three groups of neonates at three different
ages: 10 premature infants, 6 full-terms and 7 older infants (4 to 6 months).
Thermal stimulation was achieved by placing a hot and cold surface on the
subject's right palm alternately at three different rates: replacing the touching
surface every 4 s (0.25 Hz), 7 s (0.14 Hz) and 10 s (0.1 Hz). 'Double period'
stimulation was defined as the total duration of each period of hot and cold
stimulation at the three rates, namely 8 s (0.125 Hz), 14 s (0.07 Hz), 20 s (0.05
Hz). The ECG of every infant was measured and recorded during the various stages
of the experiment. The HR power spectrum from 0.02 Hz up to 2.00 Hz was
considered, focusing on narrow ranges around the thermal stimulation frequencies.
We found that in most subjects, clear peaks arise in the HR PS at the thermal
entrainment frequency and its corresponding half frequency ('double period'). In
premature infants, the reaction is best in response to the longest (10 s)
stimulus (9 out of 10 prematures reacted positively), in group B (full-term
infants) the reaction responds best to the 7-s stimulus (6 out of 6 reacted) and
in older infants the reaction is slightly better at the 4-s stimulus. Since
sympathetic control is slower, this ability to entrain the control system at
increasing frequencies, might be related to the gradual maturation of
parasympathetic control after birth. The different reaction of the three groups
may help to understand the maturation process of the thermoregulation system.
PMID- 9758249
TI - Neurodevelopmental outcome at three years of age after fetal 'brain-sparing'.
AB - Intrauterine growth restriction (IUGR), occurring preterm, may be related to
impaired neurodevelopmental outcome. We measured neurodevelopmental outcome
(Hempel examination) at the age of three years in a cohort of infants born
between 26 and 33 weeks in 1989. Fetuses were studied haemodynamically, using
Doppler ultrasound. The ratio between the umbilical and the cerebral artery
Pulsatility Index (U/C ratio) was calculated. This is a measure of redistribution
of fetal blood preferentially to the brain and this may be a marker of fetal
adaptation to placental insufficiency. Impaired fetal growth was also measured by
the fetal growth ratio. Neonatal cranial ultrasound was performed to document
intracranial haemorrhages and/or ischaemia. From the original cohort of 106
infants, 96 (91%) infants were examined at three years. After adjustment for
obstetric variables, adverse Hempel outcome was related to neonatal cranial
ultrasound abnormality and low head circumference at three years. Neither the U/C
ratio nor fetal growth were independently associated with Hempel outcome. Fetal
'brain-sparing' in IUGR appears to be a benign adaptive mechanism preventing
severe brain damage.
PMID- 9758250
TI - Cardiac regression sequence: reversal of blood flow is diagnostic but not
causative in an acardiac fetus.
AB - In 1% of monozygotic twin pregnancies, one fetus is without a heart; blood
circulation is maintained by an accompanying "pump" twin. Such an acardiac
condition is usually diagnosed on the basis of further malformations visible by
ultrasonography. We describe a monoamniotic twin pregnancy with early growth
reduction in one twin. His skeleton and the shape of the body including the head
were normal; however, heart, lungs and liver were absent. "Death of one twin" had
thus been the diagnosis before termination of pregnancy. Studies of the blood
flow in acardiac fetuses by several investigators have shown that perfusion of a
heartless fetus is opposite to the normal direction and the term "twin reversed
arterial perfusion sequence" has been proposed. While "reversed arterial
perfusion" might be a key diagnostic element for the ultrasonographic examination
of the acardiac condition, it need not necessarily be the primary cause. A lethal
defect in early heart development is much more likely to be the primary event
which is temporarily rescued by the presence of the accompanying "pump" twin. A
term like "cardiac regression sequence" would be much better suited to describe
the condition.
PMID- 9758251
TI - Lactate, lactate/pyruvate ratio and catecholamine interrelations in cord blood at
delivery in complicated pregnancies.
AB - The interrelationships between lactate, lactate/pyruvate (L/P) ratio and
catecholamines (CA) in cord artery and vein blood were studied in 56 pregnancies
who had complications in the antenatal period or during labour. This group of
babies had higher CA levels and were more acidaemic than fetuses after normal
pregnancies and labour. There were stronger correlations between lactate and
noradrenaline (NA) (R = 0.56, P < 0.001), adrenaline (A) (R = 0.41, P = 0.002)
and dopamine (DA) (R = 0.42, P = 0.001) in cord artery blood, than previously
reported for normal deliveries. Correlations between L/P ratio and CAs were also
significant, although weaker. Multiple regression analysis, using cord artery
lactate as the dependent variable, revealed significant correlations for pH (P =
0.01) and pyruvate (P < 0.001) but not for the CAs. The subgroups with high
lactate (> 75th centile) had significantly higher NA (P = 0.007) and DA (P <
0.001) in cord artery and NA (P < 0.001) and A (P < 0.001) in cord vein blood, as
compared with the subgroup who had lower lactate concentrations. We conclude that
fetal hypoxia induces fetal CA production as well as anaerobic metabolism with
lactate production. However, the adrenergic stimulation seems not to contribute
significantly to the fetal lactate production.
PMID- 9758252
TI - Aspects of malignant progression of vulvar epithelial disorders.
PMID- 9758253
TI - Hysterectomy: indications, surgical routes, cases for adnexal or cervical
conservation.
PMID- 9758254
TI - Hypertrophic cardiomyopathy and pregnancy.
AB - The case of a young primiparous woman with defibrillator-assisted familial
hypertrophic cardiomyopathy (HCM) has led us to review the literature on this
pathology, which is exceptional because of its scarcity and the originality of
the problems encountered. To our knowledge, this is the first observation ever
reported of defibrillator-assisted activation during pregnancy in a woman with
HCM. Several questions raised from this particular case, e.g. what are the risks
caused by pregnancy in these patients, what is the impact of therapeutics, does
the activation of an internal defibrillator involve particular risks, what is the
best disposition for delivery and what are the risks for fetuses? We have tried
to ask all of these questions, using as exhaustive a literature review as
possible.
PMID- 9758255
TI - Urolithiasis in pregnancy--a clinical challenge.
AB - Symptomatic urolithiasis in pregnancy is a rare event. We present a series of 13
cases. Although controversial, we think that X-rays should be avoided if
possible. Ultrasound may not be the perfect diagnostic tool in every case of
stone disease, however in pregnancy it is the imaging of choice and led to an
accurate diagnosis in all our cases. Thirty-eight percent of the patients were
managed conservatively throughout their pregnancy, and another thirty-eight
percent of our patients needed more extended treatment but could be managed by
simple insertion of a double J ureteric stent (DJ). Therefore, in our series
invasive treatment was not necessary in the majority of patients. Each one
patient required a percutaneous nephrostomy (PCN) and a nephrectomy for a non
functional pyonephrotic kidney. Urolithiasis in pregnant women constitutes a
challenge for the treating urologists since they are deprived of some of their
essential tools, such as X-rays and extracorporeal shock wave lithotripsy (ESWL),
and since normally tolerable complications of less invasive treatments can have
disastrous consequences in pregnant patients. Therefore, decisions on any kind of
treatment have to be made very prudently and critically. We present an algorithm
for the management of stones in pregnancy which may be helpful in decision
making.
PMID- 9758256
TI - Relevance of serum bile acid profile in the diagnosis of intrahepatic cholestasis
of pregnancy in an high incidence area: Portugal.
AB - OBJECTIVE(S): The present work was conducted to clarify the relevance of usual
liver function tests, and define the most predictive serum bile acid profile for
diagnosis of intrahepatic cholestasis of pregnancy (ICP). STUDY DESIGN: This
study comprised 20 healthy nonpregnant women and 77 pregnant women in the last
trimester of pregnancy, from which 38 were normal pregnancies, and 39 suffered
from ICP. Liver function tests were evaluated by routine laboratory techniques,
conjugated bile acids were analysed by high-performance liquid chromatography,
and unconjugated forms were measured by an enzymatic-fluorimetric assay. RESULTS:
During the third trimester in normal pregnancy, increased concentration of
conjugated species affected all primary bile acids, although only significantly
for glycocholic acid. Moreover, deoxycholic acid proportion decreased when
compared with healthy nonpregnant women. Important ICP-induced changes in serum
profiles of amidated bile acids were observed, involving both a marked increase
in cholic acid concentration and a shift towards a higher proportion of taurine
conjugated species. Among routine liver tests, alanine aminotransferase and
conjugated bilirubin were the most common indicators of ICP. CONCLUSION(S): In
the early diagnosis and follow-up of ICP, the most predictive and accurate
markers (efficiency 100%) were: (i) TBA concentration in serum >11.0 micromol(
1): (ii) cholic/chenodeoxycholic acid ratio >1.5 and cholic acid percentage >42%:
(iii) glycine/taurine bile acid ratio <1.0 or glycocholic acid concentration >2.0
micromol(-1). Accurate diagnosis based on sensitive biochemical markers followed
by appropriate treatment may improve both pregnancy outcome and newborn
prognosis.
PMID- 9758257
TI - Maternal and fetal plasma concentrations of endothelin, lipidhydroperoxides,
glutathione peroxidase and fibronectin in relation to abnormal umbilical artery
velocimetry.
AB - OBJECTIVE: To study plasma concentrations of endothelin (ET), lipidhydroperoxides
(LOOH), glutathione peroxidase (GSHpx) and fibronectin in relation to abnormal
umbilical artery velocimetry. STUDY DESIGN: Plasma concentrations of ET, LOOH,
GSHpx and fibronectin were measured in fetal and maternal venous blood in: (i) a
control group (n=10); (ii) in pregnancies complicated by intrauterine growth
retardation (IUGR) (n=6) or preeclampsia (n=5) with positive end diastolic flow;
and in (iii) pregnancies complicated by absent or reversed end diastolic (ARED)
flow in the umbilical artery (n=18). All children were delivered by primary
caesarean section. RESULTS: The significantly highest maternal and fetal ET
concentrations were found in plasma collected in pregnancies complicated by ARED
flow in the umbilical artery. Maternal fibronectin levels were significantly
raised in the ARED flow group. Maternal plasma ET levels were lowest in
pregnancies complicated by IUGR. The maternal and fetal plasma concentrations of
LOOH and GSHpx did not differ significantly between the groups. CONCLUSION:
Abnormal Doppler velocimetry, especially ARED flow is associated with elevated
maternal and fetal plasma levels of ET. The exact mechanism causing the placental
vasoconstriction is unknown yet, but oxidative stress seems not to be involved.
PMID- 9758258
TI - A prospective study of persistent back pain after pregnancy.
AB - OBJECTIVES: To determine the prevalence of back pain after delivery and its
relationship to individual factors. STUDY DESIGN: A cohort of 88 pregnant women,
aged 14-46 years, who had suffered from back pain during pregnancy, and delivered
at Aydin Maternity Hospital was selected. They had been followed up through
pregnancy, and 6 months post partum filled out a questionnaire. The data were
analyzed statistically. RESULTS: Follow-up showed that back pain at the time of
delivery and 6 months post partum was reported by 59.1% and 43.2% of the women,
respectively. The difference in prevalence of back pain between young women and
older ones was statistically significant (P=0.000). The number of previous
pregnancies increased the risk of back pain (P=0.000), but there was no
difference in prevalence of back pain between women with heavy work and without
heavy work before pregnancy (P=0.310). Furthermore, women with a history of back
pain before pregnancy were found to experience more intense pain at 6 months post
partum compared to those without a history of back pain before pregnancy (2.1+/
1.0 and 0.4+/-0.4. respectively. P=0.000). CONCLUSION: These results indicate
that pregnant women with a previous history of back pain had a higher prevalence
of back pain, especially in young multigravid patients.
PMID- 9758259
TI - Low-molecular-weight heparin combined with aspirin in pregnant women with
thrombophilia and a history of preeclampsia or fetal growth restriction: a
preliminary study.
AB - OBJECTIVE: To assess the prevalence of haemostatic abnormalities in patients with
an obstetric history of preeclampsia and/or fetal growth restriction and
documented thrombophilia, and to evaluate the effects of low-molecular-weight
heparin (LMWH) and aspirin on pregnancy outcome. METHOD: A total of 276 patients
with a history of preeclampsia and/or fetal growth restriction were tested for
the presence of coagulation abnormalities and anticardiolipin antibodies (ACA).
Ninety patients with preeclampsia and 15 patients with isolated fetal growth
restriction had haemostatic abnormalities. Twenty-six patients with coagulation
abnormalities: protein S-deficiency, activated protein C (APC) resistance and/or
> or =15 ACA GPL and/or MPL had a subsequent pregnancy and were treated with
aspirin in combination with LMWH. Their pregnancy outcome was compared with all
patients having a subsequent pregnancy from the same cohort without
abnormalities, or <15 ACA GPL and/or MPL who received aspirin (n=19). RESULTS: In
subsequent pregnancies birth weight of babies born to patients with an
unequivocal coagulation abnormality (i.e., protein S-deficiency, APC resistance,
or ACA titres > or =15 GPL and/or MPL), were higher than in the group with no
disorders or <15 ACA GPL and/or MPL (P=0.019). CONCLUSIONS: In this preliminary
study, LMWH appears to have a favourable effect on the pregnancy outcome of women
with a history of preeclampsia and/or fetal growth restriction and documented
thrombophilia. Randomised trials are required.
PMID- 9758260
TI - Contribution of congenital malformations to perinatal mortality. A 10 years
prospective regional study in The Netherlands.
AB - OBJECTIVE: : To determine the precise contribution of congenital malformations to
perinatal mortality in a region. DESIGN: Prospective, descriptive. SETTING:
Region, Delft-Westland-Oostland (DWO) in the Netherlands. MATERIAL AND METHODS:
The registration was based on data concerning all deliveries of women domiciled
in the health region DWO of the Netherlands. The incidence and contribution of
congenital malformations to perinatal death was evaluated by a team consisting of
a gynaecologist. a paediatrician and a paediatric pathologist. Malformations were
classified as lethal or nonlethal and recorded separately for stillbirth (from 28
weeks gestation) and liveborn infants with 7-day follow-up. RESULTS: In 10 years
(1993-1992) 28983 children were born in the region DWO. The perinatal mortality
was calculated as 247 cases (0.85%). The overall incidence of congenital
malformations in the perinatal death-group was 33%. Lethal congenital
malformations were found in 51% of the cases in the stillbirth-group and 70% of
the cases in the neonatal death-group. Congenital malformations of the central
nervous system are mostly lethal in the stillbirth-group (45%). Cardiovascular-
and pulmonary-defects were more prominent in the neonatal period (27% and 33%
respectively of the neonatal deaths). Uro-genital and minor malformations
(miscellaneous) are more often seen in perinatal deaths without being a
contributor to the cause of death. CONCLUSIONS: As most congenital malformations
are multifactorial in origin, it is in the understanding and control of such
conditions that efforts and resources should now be turned. Through a detailed
postmortem fetal and placental examination and clinical-pathological correlations
lethal congenital malformations were found in 51% in stillbirths (mainly central
nervous system) and 70% in neonates (mainly cardiovascular and pulmonary
defects).
PMID- 9758261
TI - Vitamin B12 levels in pregnancy influence erythropoietin response to anemia.
AB - OBJECTIVE: to discover whether vitamin B12 levels influence erythropoietin (EPO)
response during pregnancy. STUDY DESIGN: 117 pregnant women after the 27th week
were divided into three groups according to log vitamin B12 concentrations. EPO
(by enzyme-linked immunosorbent assay), Hemoglobin (Hb) and medium corpuscular Hb
concentration (MCHC) were measured in these patients. The tests used were:
calculation of simple statistic, regression coefficient and t-independent test
with level of significance. An exclusive partitioned cluster method (K-means
procedure) was used. RESULTS: For the lowest vitamin B12 levels there is an
unexpected lack of difference in plasma EPO levels between anemic and nonanemic
patients. In fact EPO levels were high even in nonanemic women. The only
parameter of the blood count that seems to change in relation to vitamin B12
concentration is the MCHC. CONCLUSIONS: These results suggest that low vitamin
B12 levels inhibit the suppression of EPO response in nonanemic pregnant women
probably through MCHC modifications.
PMID- 9758262
TI - Cervicovaginal fetal fibronectin concentrations: predictive value of impending
birth in postterm pregnancies.
AB - OBJECTIVE: To determine the predictive value of cervicovaginal fetal fibronectin
(fFN) concentrations > or =50 ng/ml for spontaneous onset of labour within 3 days
in pregnancies of 41 weeks gestation or more. STUDY DESIGN: In the Department of
Obstetrics, Leiden University Medical Centre, and of the Diaconessen Hospital,
Voorburg (The Netherlands), 126 cervicovaginal secretions of fFN, from 80
consenting women between 287 and 304 days gestation were collected. Pregnant
women underwent sterile speculum examinations for cervicovaginal sampling from
the 41st week onwards. The fFN concentration in these samples was determined with
a quantitative solid-phase enzyme-linked immunosorbent assay. Concentrations of
<50 ng fFN per ml were characterised as negative test results, meaning that
spontaneous delivery would not take place within 3 days, and those of > or =50
fFN ng/ml were taken as positive test results. Sensitivity and specificity of the
fFN test were calculated for predicting spontaneous birth. Parametric and
nonparametric tests were used for evaluating differences and correlations.
RESULTS: Spontaneous delivery took place after 2.5+/-2.5(SD) days with fFN values
> or =50 ng/ml and after 4.7+/-3.6 days with fFN concentrations <50 ng/ml
(P<0.001). Sensitivity and specificity of the fFN test predicting spontaneous
onset of labour within 3 days, were 0.71 [95% confidence interval (CI) 0.58-0.86]
and 0.64 (95% CI 0.48-0.78). If fFN > or =50 ng/ml then a spontaneous onset of
labour is more likely to occur within 3 days (odds ratio 4.5 (95% CI 1.8-11.3).
CONCLUSIONS: The fFN test does not predict accurately enough whether or not birth
will take place within 3 days of sampling. Nevertheless, the higher odds for
spontaneous delivery within a few days when the test is positive may be of use in
planning adjusted induction of labour.
PMID- 9758263
TI - Malignant fibrous histiocytoma of the stomach during pregnancy: a case report.
AB - In this case report we describe a patient with a primary malignant fibrous
histiocytoma of the stomach, diagnosed and operated upon during the sixth month
of pregnancy. We stress the importance of a thorough diagnostic examination in
cases of severe anaemia during pregnancy. Although very rare, malignancy of the
gastrointestinal tract should be taken in consideration. No holding back is
justified in diagnostic and therapeutic measurements because of pregnancy.
Radiologic examination of the gastrointestinal tract should be replaced by
endoscopy.
PMID- 9758264
TI - Epileptogenic activity of folic acid after drug induces SLE (folic acid and
epilepsy)
AB - OBJECTIVE: To study the effect of folic acid-containing multivitamin
supplementation in epileptic women before and during pregnancy in order to
determine the rate of structural birth defects and epilepsy-related side effects.
STUDY DESIGN: First a randomised trial, later periconception care including in
total 12225 females. RESULTS: Of 60 epileptic women with periconceptional folic
acid (0.8 mg)-containing multivitamin supplementation, no one developed epilepsy
related side effects during the periconception period. One epileptic woman
delivered a newborn with cleft lip and palate. Another patient exhibited with a
cluster of seizures after the periconception period using another multivitamin.
This 22-year-old epileptic woman was treated continuously by carbamazepine and a
folic acid (1 mg)-containing multivitamin from the 20th week of gestation. She
developed status epilepticus and later symptoms of systemic lupus erythematodes.
Her pregnancy ended with stillbirth. CONCLUSIONS: The epileptic pregnant
patient's autoimmune disease (probably drug-induced lupus) could damage the blood
brain barrier, therefore the therapeutic dose (> or =1 mg) of folic acid
triggered a cluster of seizures. Physiological dose (<1 mg) of folic acid both in
healthy and 60 epileptic women, all without any autoimmune disease, did not
increase the risk for epileptic seizures.
PMID- 9758265
TI - Within-subject variability of differences between conventional and automated
blood pressure measurements in pregnancy.
AB - OBJECTIVE: To determine whether measured differences between standard mercury
sphygmomanometry and the SpaceLabs 90207 ambulatory blood pressure monitor in
pregnant women remain constant during 24 h measurements. STUDY DESIGN: Repeated
comparisons between standard mercury sphygmomanometry and Spacelabs 90207 were
performed at nine predetermined time points during 24 h ambulatory blood pressure
measurements in a group of ten pregnant women with various pregnancy
complications, including hypertension. Individual and group differences between
standard mercury sphygmomanometry and SpaceLabs 90207 were calculated for each
time point. Friedman's ANOVA was used to test stability of differences across
time. RESULTS: Mean group differences (standard deviation) between mercury
sphygmomanometry and the SpaceLabs 90207 were -2 (6) mmHg and 3 (7) mmHg for
systolic and diastolic pressure respectively. For systolic pressure the
differences between time points were not statistically significant. Although a
statistical significant trend was found for diastolic pressure differences
(P<0.05), none of the contrasts between any pair of time points reached
statistical significance. For both systolic and diastolic pressure the minimal
and maximal difference lay at least 10 mmHg apart in seven patients. CONCLUSIONS:
Despite standardisation and training, a substantial within-subject variability of
the pressure difference between observers and SpaceLabs was found in this
heterogeneous group of women. However, a systematic time-related effect on this
pressure difference could not be demonstrated. The pressure difference between
both methods cannot be estimated with great precision. This is a serious
impediment for the clinical interpretation of automated or ambulatory blood
pressure data.
PMID- 9758266
TI - Pregnancy outcome after repeated blunt abdominal trauma.
AB - During a four-year period, five of 49671 parturients were admitted on a
prospective study protocol for repeated direct blunt abdominal trauma due to
falls during pregnancy. Preterm contractions were noted in three patients one of
which delivered preterm. No delayed abruptio placentae, intrauterine growth
restriction or antepartum death were encountered. All patients delivered
spontaneously. Repeated blunt abdominal trauma occurs rarely in pregnancy.
Routine hospitalised surveillance in the absence of vaginal bleeding or uterine
contractions may not be warranted.
PMID- 9758268
TI - Bilateral ureteric obstruction following vaginal hysterectomy: oedema of the
bladder can be a rare cause.
AB - Known causes of bilateral ureteric obstruction following vaginal hysterectomy and
vaginal wall repair are accidental bilateral ureteric ligation and kinking of the
ureters. A case of bilateral ureteral obstruction due to bladder wall oedema is
presented. A cause for this extreme oedematous reaction was not found. Post-renal
obstruction does not necessarily result in dilatation of the ureters, therefore
ultrasound cannot always be used to exclude a post-renal obstruction.
PMID- 9758267
TI - An anatomical classification--a new paradigm for management of female lower
urinary tract dysfunction.
AB - A new anatomical classification specifies anatomical defects in the anterior,
middle and posterior zones of the vagina as the cause of female lower urinary
tract dysfunction. An external musculoelastic mechanism stretches the vagina to
open and close the outflow tract. The same pelvic floor muscles provide a
peripheral control mechanism for micturition. The stretched vagina prevents the
filling bladder from activating the stretch receptors in the bladder neck.
Vaginal laxity may weaken transmission of muscle forces, interfering with
urethral opening and closure, a mechanical process. Laxity may also destabilize
the peripheral control mechanism, a neurological process, causing bladder control
to swing between the open and closed modes urodynamically interpreted as bladder
instability. Specific symptoms, signs, and urodynamic tests can be arranged into
a pictorial algorithm. This acts as a practical guide for locating the three
zones of anatomical defects. It has been possible to reinterpret almost all the
definitions and descriptions of the International Continence Society (ICS) in
terms of this classification, and to explain how vaginal laxity may cause
premature activation of the micturition reflex (detrusor instability), stress
incontinence and abnormal emptying (dribble, overflow). This convergence in
anatomical and urodynamic (ICS) concepts explains many previously unexplained
phenomena, and potentially opens up a new approach to management, nonsurgical
strengthening of specific ligaments, or surgical reinforcement thereof with
ambulatory "microinvasive" methods which do not require catheterization.
PMID- 9758269
TI - Biochemical hemodynamic and hematological changes during transcervical resection
of the endometrium using 1.5% glycine as the irrigating solution.
AB - OBJECTIVE: To study fluid absorption during transcervical resection of the
endometrium (TCRE) and its effect on the biochemical, hemodynamic and
hematological alterations so that life threatening complications of fluid
overload may be prevented. METHOD: Intraoperative fluid (1.5% glycine) absorption
in 46 women undergoing TCRE was studied and correlated using biochemical
parameters (serum sodium, potassium, total proteins, creatinine and blood urea),
hemodynamic parameters (pulse rate, blood pressure, oxygen saturation and end
tidal CO2) and hematological parameters. Twenty five of these patients had
received danazol (800 mg/day) for six weeks prior to TCRE. RESULT: The mean
glycine deficit during TCRE was found to be 474.45 ml, with a mean total inflow
of 3802.17 ml. Amongst all of the parameters, only serum sodium levels were found
to be significantly inversely correlated with the glycine deficit. No case of
hyponatremia occurred below a deficit of 1000 ml. Severe hyponatremia was
reported in three cases (6.4%) and all three had a glycine deficit of more than
1000 ml. No case of pulmonary edema was noted. The mean glycine deficit was
significantly lower (P=0.007) and the duration of procedure significantly shorter
(P=0.0009) in the patients who had received danazol. None of the patients in the
danazol group had fluid absorption of more than 1000 ml. CONCLUSION: Close
monitoring of fluid inflow and outflow should be done during TCRE. Above a
deficit of 1000 ml, serum sodium should be measured to detect significant
hyponatremia. The use of danazol for endometrial preparation also reduces the
mean amount of fluid absorbed.
PMID- 9758270
TI - Benign intracardiac teratoma detected prenatally. Case report and review of the
literature.
AB - Primary cardiac tumors are rare and, until recently, were mostly incidental
postmortem findings. Nowadays, due to the widespread use of prenatal ultrasound
scans, we are able to diagnose them in utero. We present a case of an
intracardiac teratoma diagnosed at 38 weeks, menstrual age. Previous scans had
been normal. Labor was induced, and a female infant with an Apgar score of 9 and
4, at 1 and 5 min, was delivered. Her condition worsened rapidly. She died 16 h
after birth. Necropsy was performed, and a cystic, mature teratoma of 4 cm was
found in the interventricular septum, growing into the right ventricle. No other
anomalies were found. This probably represents the first case of an intracardiac,
benign teratoma diagnosed prenatally.
PMID- 9758271
TI - Early detection of caudal regression syndrome: specific interest and findings in
three cases.
AB - Caudal regression syndrome (CRS) is a rare malformative syndrome seen mainly in
cases of maternal diabetes with poor metabolic control. Early detection by
vaginal ultrasound is possible. The authors describe three cases of CRS, relating
the characteristic ultrasound findings which include abrupt interruption of the
spine at the dorsal or lumbar level and abnormal position of the lower limbs. The
femur bones are fixed in a 'V' pattern, giving a typical 'Buddha's poise'.
PMID- 9758272
TI - The seventh meeting and exchange programme of European Obstetricians and
Gynaecologists in training (13-15 November, 1997, in Athens).
AB - The European Network of Trainees in Obstetrics and Gynaecology (ENTOG) is a newly
founded organisation which is closely associated with the European Board and
College of Obstetrics and Gynaecology. The main objectives of ENTOG are: (i) to
provide a forum for trainees to discuss and express their opinions on issues in
Obstetric/Gynaecology (Ob/Gyn) training; (ii) to establish a continuous means of
communication between European trainees; (iii) to promote high standards of
training and thus improve the quality of medical care. To reach these objectives,
ENTOG organizes a yearly exchange programme and educational meeting for trainees.
Recently, a meeting was held in Greece with harmonization of training programmes
in Ob/Gyn serving as a main topic.
PMID- 9758273
TI - Clinical evaluation of a commercial ligase-based gene amplification method for
detection of Mycobacterium tuberculosis.
AB - The purpose of this study was to evaluate the clinical usefulness of a commercial
ligase-based gene amplification method (LCx Mycobacterium tuberculosis test;
Abbott Laboratories, USA) for detection of Mycobacterium tuberculosis. The
tuberculosis infection rate among clinical samples was 10.6%. The sensitivity,
specificity, and positive and negative predictive values were 23.5%, 100%, 100%,
and 91.7%, respectively, with the fluorochrome auramine stain; 32.4%, 100%, 100%,
and 92.6%, respectively, with culture; and 76.5%, 95.8%, 68.4% and 97.2%,
respectively, with the gene amplification method. When only samples from patients
without current or previous treatment were studied, the sensitivity was 36.4%
with the auramine stain, 63.6% with culture, and 100% with the gene amplification
assay. The mean treatment time for culture-negative and assay-negative samples
was greater than that of culture-negative and assay-positive samples. The LCx
Mycobacterium tuberculosis test is a sensitive method for detection and
identification of Mycobacterium tuberculosis. It produces few false-positive
results. However, as it can remain positive after the culture becomes negative,
it is not recommended for evaluation of treatment efficiency.
PMID- 9758274
TI - Bacteraemia in the adult intensive care unit of a teaching hospital in
Nottingham, UK, 1985-1996.
AB - Bacteraemia is an important cause of morbidity and mortality in the intensive
care unit. In this study the distribution of organisms causing bacteraemic
episodes in patients in the adult intensive care unit of a large teaching
hospital was determined. Particular emphasis was placed on the type of organisms
isolated from community- and hospital-acquired bacteraemia, the suspected source
of infection, the possible risk factors associated with bacteraemia, and outcome.
The incidence of bacteraemia and fungaemia increased from 17.7 per 1000
admissions in 1985 to 80.3 in 1996. A total of 315 episodes of bacteraemia and
fungaemia were documented over a 12-year period, of which 18% were considered
community-acquired and 82% hospital-acquired. Gram-positive and gram-negative
bacteria accounted for 46.9% and 31.5% of the episodes, respectively.
Polymicrobial infection accounted for 17.8% and fungi for 3.8% of the episodes.
Staphylococcus aureus (22.5%), Staphylococcus epidermidis (7.6%), and
Streptococcus pneumoniae (7.9%) were the predominant gram-positive bacteria
implicated, whereas Escherichia coli (6%), Enterobacter cloacae (7%), Klebsiella
aerogenes (3.8%), Pseudomonas aeruginosa (5.1%), and Acinetobacter spp. (3.8%)
were the predominant gram-negative bacteria isolated. The two most common sources
of infection were the respiratory tract (39.7%) and an intravascular line
(24.5%), but in 8.9% of episodes the focus of infection remained unknown.
Bacteraemic patients stayed in the unit for a longer period (12 days) than did
non-bacteraemic patients (3 days). The overall mortality related to bacteraemia
and candidaemia was 44.4%. Surveillance of bacteraemia in the intensive care unit
is important in detecting major changes in aetiology, e.g., the increasing
incidence of gram-positive bacteraemia, the emergence of methicillin-resistant
Staphylococcus aureus in 1995, and the emergence of Enterobacter cloacae. It is
of value in determining empirical antimicrobial therapy to treat presumed
infection pending a microbiological diagnosis and in directing the development of
guidelines for infection prevention, e.g., guidelines for central venous catheter
care.
PMID- 9758275
TI - Antibiotic resistance in Salmonella enterica serotype typhimurium.
AB - In order to analyse the development of antibiotic resistance in Salmonella spp.,
a total of 262 Salmonella strains isolated in 1987 (n = 148) and in 1996 (n =
114) from clinical specimens in Wurzburg, Germany, were tested in parallel by the
agar diffusion method. In 1987. most of the strains were Salmonella enterica
serotype typhimurium (42.6%), whereas in 1996 most were Salmonella enterica
serotype enteritidis (68.4%). The majority of Salmonella enterica serotype
enteritidis isolates was fully susceptible in 1987 and 1996. In contrast, the
percentage of drug-resistant strains of Salmonella enterica serotype typhimurium
increased significantly from 27% in 1987 to 52.4% in 1996. This increase, which
might reflect uncontrolled use of antibiotics in the environment, should be of
concern to public health authorities.
PMID- 9758276
TI - Radiometric quantification of Mycobacterium avium complex.
AB - The purpose of this study was to establish a system that would allow rapid and
reliable quantification of Mycobacterium avium complex infection with a method
that was as sensitive as counting of colony-forming units but less time-consuming
and safer in the laboratory. The radiometric system for quantification of
mycobacteria (Bactec, Becton Dickinson, USA) which calculates growth curves, was
found to be faster, safer, and as sensitive as the established method of counting
colony-forming units, with a low intra-assay variation and a wide assay range.
Furthermore, the calculated growth curves provided important additional
information about replication characteristics of the mycobacteria.
PMID- 9758277
TI - Comparison of three media for agar dilution susceptibility testing of Bordetella
pertussis using six antibiotics.
AB - Since antimicrobial susceptibility testing of the fastidious species Bordetella
pertussis is not standardized, the most suitable medium for agar dilution testing
of this species has not yet been determined. In the present study, Mueller
Hinton, Bordet-Gengou, and Oxoid charcoal agars (each supplemented with 5% horse
blood) were evaluated for agar dilution susceptibility testing of Bordetella
pertussis against ampicillin, chloramphenicol, ciprofloxacin, doxycycline,
erythromycin, and trimethoprim-sulfamethoxazole. Mueller-Hinton agar was the most
suitable medium.
PMID- 9758279
TI - In vitro activity of mupirocin against methicillin-resistant Staphylococcus
aureus isolated from a hospital in Spain.
PMID- 9758280
TI - Urinary tract infection due to Arcanobacterium bernardiae in a patient with a
urinary tract diversion.
PMID- 9758278
TI - Non-tuberculous mycobacterial infection in children with cancer.
AB - Reported here is the clinical presentation and management of patients with
rapidly growing non-tuberculous mycobacterial infection diagnosed in a paediatric
oncology unit. A retrospective analysis that correlated patient isolates with the
children's cancer registry revealed two cases of non-tuberculous mycobacterial
infection; both had been observed within the last 6 years and were due to
Mycobacterium chelonae. The first case was line-associated and the second was a
disseminated infection. In both cases the patients were lymphopenic and had had
indwelling vascular catheters. Neither patient was neutropenic. The literature on
mycobacterial infection in children with cancer is also reviewed.
PMID- 9758281
TI - Association between quinupristin/dalfopristin resistance in glycopeptide
resistant Enterococcus faecium and the use of additives in animal feed.
PMID- 9758282
TI - Trovafloxacin: in vitro activity, pharmacokinetics, and clinical experience.
Introduction.
PMID- 9758283
TI - Bacteriological activity of trovafloxacin, a new quinolone, against respiratory
tract pathogens.
AB - The use of established fluoroquinolones, such as ciprofloxacin and ofloxacin, as
empirical therapy for the treatment of moderate-to-severe respiratory tract
infections is limited by their poor activity against gram-positive and atypical
pathogens. Data from in vitro susceptibility studies and in vivo animal
protection models suggest that the new fluoroquinolone, trovafloxacin, compared
with ciprofloxacin and ofloxacin offers equivalent activity against gram-negative
pathogens and improved activity against gram-positive pathogens. In particular,
susceptibility data indicate that trovafloxacin is at least 16-fold more potent
than either ciprofloxacin or ofloxacin against penicillin-susceptible and
penicillin-resistant strains of Streptococcus pneumoniae. Other susceptible
pathogens include Streptococcus pyogenes, vancomycin-susceptible Enterococcus
faecalis and the atypical respiratory pathogens Legionella pneumophila,
Mycoplasma pneumoniae and Chlamydia pneumoniae. In vivo studies involving models
of protection against acute systemic infection and pneumococcal pneumonia in
mice, and Legionnaires' disease in guinea pigs, indicate that the antibacterial
spectrum observed for trovafloxacin in vitro extends to the in vivo setting.
Together, these findings suggest that trovafloxacin may offer clinical efficacy
against respiratory pathogens superior to that of ciprofloxacin and of ofloxacin,
and may find a useful role as empiric therapy in both the community and hospital
setting.
PMID- 9758285
TI - A comparative study on the efficacy of the new quinolone alatrofloxacin in the
treatment of experimental legionellosis in guinea pigs.
AB - The in vivo efficacy of trovafloxacin, intraperitoneally administered as
alatrofloxacin (CP-116,517), was assessed and compared with that of erythromycin,
alone or in combination with rifampicin, in a model of Legionella pneumophila
pneumonia in guinea pigs. Trovafloxacin (5 mg/kg administered as alatrofloxacin
once daily for 7 days) gave a survival rate of 100% in infected animals.
Clearance of bacteria and of bacteria-induced lesions from lungs was achieved by
day 6 post-inoculation. The lungs of trovafloxacin-treated animals remained free
of bacteria at day 28 post-challenge. Trovafloxacin proved as effective as
erythromycin administered intraperitoneally, but was superior to erythromycin
alone. or in combination with rifampicin, when given orally.
PMID- 9758286
TI - Hepatobiliary elimination of trovafloxacin and metabolites following single oral
doses in healthy volunteers.
AB - Trovafloxacin, a fluoronaphthyridone derivative related to fluoroquinolones, has
significant activity against gram-negative and gram-positive pathogens, including
penicillin-resistant Streptococcus pneumoniae, anaerobes and atypical organisms,
good tissue penetration and a long elimination half-life. Following oral
administration, less than 10% of the dose is renally eliminated as unchanged
drug. Hepatobiliary elimination of trovafloxacin was examined by comparing the
time course and bile and serum concentrations of trovafloxacin and its
metabolites following oral administration to three patients with in-dwelling
nasobiliary catheters or T-tubes. Following a single 200 mg oral dose, the mean
maximum plasma trovafloxacin concentration was 2.0+/-0.4 mg/l, the area under the
concentration-time curve 22.0+/-5.5 mg x h/l and the elimination half-life 8.5 h.
Values in bile for the same subjects were 27.8+/-9.6 mg/l, 327.7+/-142.9 mg x h/l
and 10.7 h. Corresponding values for the N-acetyl metabolite in bile were 3.8+/
3.4 mg/l, 35.3+/-29.8 mg x h/l and 8.3 h. The mean bile : serum ratio of
trovafloxacin was 14:9 and consistent with biliary elimination. Serum
concentrations of trovafloxacin in this study were similar to those reported in
healthy volunteers. Bile concentrations of trovafloxacin substantially exceeded
those of the N-acetyl metabolite, suggesting efficient clearance of the
metabolite or that hepatic metabolism of trovafloxacin is not extensive.
PMID- 9758284
TI - Susceptibility of European respiratory tract isolates to trovafloxacin,
ciprofloxacin, clarithromycin, azithromycin and ampicillin.
AB - As part of the Artemis project, 11500 isolates (3000 from patients with
respiratory tract infections) were collected throughout six European countries
between 1994 and 1996. Twenty-seven hospitals or laboratories participated in
this first phase of the study. The activities of three classes of antimicrobial
agents (fluoroquinolones, beta-lactam agents, macrolides) are presented for the
six most frequently isolated pathogens (Streptococcus pneumoniae, Staphylococcus
aureus, Haemophilus influenzae, Moraxella catarrhalis, Pseudomonas aeruginosa,
Klebsiella pneumoniae). Overall, trovafloxacin and ciprofloxacin activities were
similar for Haemophilus influenzae, Moraxella catarrhalis and Klebsiella
pneumoniae isolates. Of the Streptococcus pneumoniae isolates, 6% were resistant
to penicillin. Trovafloxacin had the highest activity against the Streptococcus
pneumoniae isolates, with a minimum inhibitory concentration of 0.25 mg/l for 90%
of isolates (MIC90); all strains tested were susceptible to trovafloxacin. The
MIC90 of ciprofloxacin for Streptococcus pneumoniae was 3 mg/l, and overall 52%
of the strains were susceptible; 9% were resistant. Azithromycin and
clarithromycin exhibited similar activity against all collected pathogens, except
Haemophilus influenzae. All strains of Haemophilus influenzae were susceptible to
azithromycin compared with 79% for clarithromycin, with respective MIC90s of 2
and 16 mg/l. The data presented demonstrate differences in the susceptibility
patterns of six major respiratory tract pathogens in Europe.
PMID- 9758287
TI - Single- and multiple-dose administration, dosing regimens, and pharmacokinetics
of trovafloxacin and alatrofloxacin in humans.
AB - A simplified dosing algorithm for trovafloxacin was evaluated following a single
dose infusion of alatrofloxacin at trovafloxacin equivalent doses of 30, 100,
200, 300 and 400 mg (57 subjects), and multiple doses of 200, 300 and 400 mg (30
subjects). Maximum serum concentration and area under the concentration-time
curve for trovafloxacin increased with dose. Trovafloxacin clearance (82-85 ml x
h/kg) and volume of distribution (1.3-1.6 l/kg) were independent of dose.
Infusion of alatrofloxacin at a trovafloxacin equivalent dose of 300 mg at 1, 2
or 3 mg/ml over 1 h did not alter the pharmacokinetics of trovafloxacin. A plot
of the weight-adjusted dose of trovafloxacin in individual subjects against the
maximum serum concentration following single and multiple dosing, indicated that
the maximum serum concentration increased 1 microg/ml for each 1 mg/kg of
trovafloxacin administered. Thus, a prior knowledge of the desired serum
concentration will permit appropriate dosing without the use of complex nomograms
in patients with normal hepatic function.
PMID- 9758288
TI - An open, controlled, crossover study on the effects of cimetidine on the steady
state pharmacokinetics of trovafloxacin.
AB - Twelve healthy male volunteers participated in this open, randomized, placebo
controlled, two-way crossover study to investigate the effects of cimetidine on
the steady-state pharmacokinetics of oral trovafloxacin. Volunteers were
randomized to receive either 400 mg cimetidine twice daily or placebo for 5 days.
From day 3-5, volunteers received 200 mg trovafloxacin once daily in addition to
either cimetidine or placebo. After a minimum 7-day washout period, the study was
repeated: those volunteers who received placebo during the first study period
were administered cimetidine, and vice versa. The maximum observed serum
trovafloxacin concentration, the area under the concentration-time curve of
trovafloxacin within the dosing interval of 24 h and the earliest time to the
maximum serum concentration for trovafloxacin in volunteers receiving concomitant
cimetidine were 2.4 microg/ml. 27.8 microg x h/ml and 1.4 h, respectively,
compared with 2.5 microg/ml, 27.1 microg x h/ml and 1.5 h, respectively, in
volunteers receiving concomitant placebo. Thus. multiple dosing with cimetidine
had no significant effect on the absorption or disposition of trovafloxacin at
steady state. Co-administration of cimetidine and trovafloxacin was also well
tolerated and without serious adverse effects.
PMID- 9758289
TI - Trovafloxacin versus amoxicillin/clavulanic acid in the treatment of acute
exacerbations of chronic obstructive bronchitis.
AB - Treatments with once-daily trovafloxacin (200 or 100 mg) and
amoxicillin/clavulanic acid (500/125 mg three times daily) were compared in
adults with acute exacerbations of chronic obstructive bronchitis. At end of
treatment, 95% (113/119) of clinically evaluable patients receiving trovafloxacin
200 mg, 98% (113/115) of patients treated with trovafloxacin 100 mg and 97%
(113/117) of patients receiving amoxicillin/clavulanic acid were cured or
improved. At study end, 91%, 87% and 88%, respectively, were cured or improved.
At end of treatment, trovafloxacin 200 mg eradicated Haemophilus influenzae in
97% of patients, Streptococcus pneumoniae in 90% and Chlamydia pneumoniae in
100%. The respective eradication rates for trovafloxacin 100 mg were 84%, 100%
and 100%; those for amoxicillin/clavulanic acid were 92%, 100% and 100%. At study
end, trovafloxacin 200 mg totally eradicated all three pathogens. Trovafloxacin
100 mg eradicated Haemophilus influenzae in 91% of patients, Streptococcus
pneumoniae in 100% and Chlamydia pneumoniae in 80%. Respective eradication rates
for amoxicillin/clavulanic acid were 78%, 100% and 80%. Only 7% (10/144) of
patients receiving trovafloxacin 200 mg reported treatment-related adverse
events, as did 7% (10/135) of patients given trovafloxacin 100 mg and 12%
(17/140) of patients given amoxicillin/clavulanic acid.
PMID- 9758290
TI - Treatment of acute exacerbations of chronic bronchitis: comparison of
trovafloxacin and amoxicillin in a multicentre, double-blind, double-dummy study.
Trovafloxacin Bronchitis Study Group.
AB - The efficacy and safety of trovafloxacin and amoxicillin were compared in a
double-blind, double-dummy multicentre trial involving 412 patients (> or = 40
years of age) with acute exacerbations of chronic bronchitis (AECBs). Patients
were randomized to 5 days' oral treatment with 200 or 100 mg trovafloxacin
administered once daily, or 500 mg amoxicillin given three times daily. Overall
clinical efficacy at the end of therapy was similar in each treatment group, with
clinical success (cure+improvement) achieved in 88% and 91% of clinically
evaluable patients receiving trovafloxacin 200 mg and 100 mg, respectively, and
in 89% of amoxicillin-treated patients. Corresponding rates at follow-up were
77%, 85% and 79%, respectively. Similar responses were noted at the end of
treatment and end of study in the intent-to-treat patients. Although all three
treatments produced similar bacteriological efficacy, there was a trend towards
higher eradication rates for Haemophilus influenzae among patients (both
clinically evaluable and intent-to-treat populations) treated with trovafloxacin
200 mg compared with those treated with amoxicillin. Both drugs were well
tolerated, with treatment-related adverse events, of which headache and
gastrointestinal disturbances were the most common, occurring in 12% and 6% of
patients in the trovafloxacin 200 mg and 100 mg groups, respectively, and in 9%
of amoxicillin-treated patients.
PMID- 9758291
TI - Trovafloxacin versus high-dose amoxicillin (1 g three times daily) in the
treatment of community-acquired bacterial pneumonia.
AB - Once-daily trovafloxacin 200 mg was compared with high-dose amoxicillin, 1 g
three times daily, given for 7 to 10 days. At end of treatment (day 10), the
response was clinically successful (cure + improvement) in 93% of 152 clinically
evaluable trovafloxacin patients and in 89% of 160 amoxicillin patients. At study
end (day 35), respective rates were 91% and 81% (95% confidence interval: 1.6,
17.6; P=0.01). In evaluable patients with positive baseline radiographs, 93% of
trovafloxacin and 88% of amoxicillin patients demonstrated radiological
resolution at end of treatment. Streptococcus pneumoniae and Haemophilus
influenzae eradication rates were comparable at end of treatment in both
treatment groups, but at study end Streptococcus pneumoniae eradication rates
were higher in trovafloxacin patients (100% vs 81%). At study end, all four
trovafloxacin patients with baseline penicillin-resistant Streptococcus
pneumoniae were clinically cured with pathogen eradication, whereas two of five
amoxicillin patients with baseline penicillin-resistant Streptococcus pneumoniae
were clinical failures with pathogen persistence. For patients in whom no
pathogen was identified, trovafloxacin was significantly more effective at end of
treatment (P=0.096) and study end (P=0.013). Treatment-related adverse events
were comparable; the most common were headache, vomiting and dizziness in
trovafloxacin patients, and diarrhoea. headache and abdominal pain in amoxicillin
patients.
PMID- 9758293
TI - Acute ischaemic stroke: revascularizing therapy. Stroke Council of the American
Heart Association.
AB - The principal goals of thrombolytic therapy for stroke are early restitution of
cerebral blood flow, reduction of ischaemia, and attenuation of neurological
disability through lysis of an occluding thrombus and consequent rapid
restoration of circulation in the affected territory. Therapy should be initiated
as soon as possible, at least within 4-6 h of stroke onset, to prevent major
infarction and to salvage the hypoperfused but potentially viable zone adjacent
to the central ischaemic area known as the ischaemic penumbra. This survey
focuses on the safety and efficacy of thrombolytic therapy in acute ischaemic
stroke in clinical trials. The results of two successful major randomized studies
using tissue plasminogen activator (t-PA) were recently published. Intravenous
thrombolysis seemed to be effective in improving functional and neurological
outcome in a clearly defined subgroup of patients meeting the inclusion criteria
of the studies. However, the identification of those patients proved to be
difficult and depended on expertise in recognizing the early infarction signs on
initial computed tomography. Since treating ineligible patients is associated
with an unacceptable risk of intracranial bleeding complications and death,
intravenous thrombolysis should only be performed at selected centres in selected
patients.
PMID- 9758292
TI - Safety of trovafloxacin in treatment of lower respiratory tract infections.
AB - Safety and toleration of oral trovafloxacin has been assessed in Phase III trials
in patients with acute lower respiratory tract infections. Patients were treated
orally with either trovafloxacin 100 or 200 mg (n=881) or a comparator (500 or
1000 mg amoxicillin, or 625 mg amoxicillin/clavulanic acid; n = 593). Adverse
events were recorded in 112 (12.7%) trovafloxacin- and 74 (12.5%) comparator
treated patients. Frequency of effects on the autonomic nervous, musculoskeletal,
respiratory, special senses, urinary and reproductive systems was <1%.
Photosensitivity reactions were not reported in trovafloxacin-treated patients.
Central or peripheral nervous system adverse effects (headache and dizziness)
were slightly more common in trovafloxacin-treated patients (4.4% vs 1.9%).
Patients treated with comparators experienced gastrointestinal events more
frequently (6.1% vs 8.3%). Comparable incidences of adverse events were reported
in patients > or = 65-years-old. Most events were mild to moderate in severity.
Treatment was discontinued because of an adverse event in 18 (2%) trovafloxacin-
and four (0.7%) comparator-treated patients. Despite the high prevalence of risk
factors, serious adverse events were rare and the mortality rate over the 35-day
study period was low: trovafloxacin 0.8%, comparator agents 1.5%. Laboratory test
abnormalities were recorded in less than 1% of patients in either treatment
group.
PMID- 9758294
TI - Neuro-ophthalmology of pupillary function--practical guidelines.
AB - An overview how to examine pupillary function and handle pupillary abnormalities
is presented. The following issues are discussed: swinging flashlight test,
clinical relevance of a relative afferent pupillary defect, anisocoria with
normal light reaction, diagnosis and evaluation of Homer's syndrome, differential
diagnosis of impaired light reaction, tonic pupil, third nerve palsy,
supranuclear pupillary disorders, iris problems, systemic disease, measurement of
sleepiness, and pupillography.
PMID- 9758295
TI - Cerebrospinal fluid magnesium level as a prognostic factor in ischaemic stroke.
AB - Magnesium has been reported to have a dilatatory effect on cerebral arteries.
Reduction of extracellular Mg+2 has been shown to be directly correlated with the
intensity of cerebral spasm. A neuroprotective effect of magnesium in stroke has
also been hypothesized. The aim of our study was to examine the Mg+2 levels in
serum and cerebrospinal fluid (CSF) in the early stage of stroke and to evaluate
the correlation between Mg+2 levels and the development of neurological deficits.
Between 1986 and 1994, 96 patients who had a stroke of 24- to 48-h duration were
enrolled in the study. Serum and CSF levels of magnesium were checked on
admission, 2448 h after the onset of stroke. Using a neurological score, the
neurological deficit was assessed on the 1st day, 1 and 4 weeks later. Computed
tomography (CT) was performed after 1 week, and the volume and location of
infarction were calculated and measured. Statistical analysis was performed for
cortical and subcortical patients separately, using Spearman correlation and
multiple linear and logistic regression analyses. Significant correlation was
found between CSF Mg+2 and the size of the infarct (P < 0.0001). There was no
correlation between serum Mg+2 and CSF Mg+2 levels. Regression analysis
demonstrated an increase in the values of the Mathew Neurological Score with
higher CSF Mg+2 levels. This association remained true after other factors such
as age, associated heart disease, diabetes and infarction size had been taken
into account by the regression model. The results confirm that there is a
relationship between a low Mg+2 concentration in CSF during the first 48 h after
onset of ischaemic stroke and the intensity of the neurological deficit. The
therapeutic consequence of this finding may have some importance.
PMID- 9758296
TI - Incidence of post-lumbar puncture syndrome reduced by reinserting the stylet: a
randomized prospective study of 600 patients.
AB - The post-lumbar puncture syndrome (PLPS) can best be explained by prolonged
spinal fluid leakage owing to delayed closure of a dural defect. Its incidence
after spinal anaesthesia is much lower than after diagnostic lumbar puncture
(LP). This difference could be caused by a strand of arachnoid, which might enter
the needle with the outflowing cerebrospinal fluid (CSF) during diagnostic LP and
upon removal of the needle be threaded back through the dura to produce prolonged
CSF leakage. To find a technique that further reduces the incidence of PLPS, this
hypothesis was tested by evaluating the effect that reinserting the stylet before
removing the needle had on the incidence of PLPS. By reinserting the stylet to
the tip of the needle, the hypothesized strand would be pushed out, thereby
reducing the frequency of PLPS. Sprotte's "atraumatic needle" (21 gauge) was used
for LP. A total of 600 patients participated in the prospective study. They were
randomized into two groups and questioned about their complaints every day for up
to 7 days after the LP. All LPs were performed by two experienced neurologists
(T.B., M.S.). In 300 patients, the stylet was reinserted to the tip of the eedle;
in the other 300 it was not reinserted. Whereas 49 of the 300 patients without
reinsertion developed PLPS, only 15 of the 300 patients with reinsertion did.
This significant difference (16.3 vs 5.0%, P < 0.005, chi square test) supports
our hypothesis. On the basis of our results, we recommend reinserting the stylet
before removing the needle in order to reduce the incidence of PLPS.
PMID- 9758297
TI - Long-term follow-up of germinoma after stereotactic biopsy and brain
radiotherapy: a cell kinetics study.
AB - The primary aim of this study is to report the long-term outcome of pineal and
suprasellar germinoma after stereotactic biopsy and whole brain radiotherapy. The
second purpose is to report an investigation of the biological features and cell
kinetics of this peculiar and enigmatic brain tumour. Of 34 supratentorial germ
cell tumours diagnosed and treated between 1980 and 1993, 20 patients were found
to be affected by true germinoma localized in the pineal and/or suprasellar
regions. The diagnosis was achieved by stereotactic biopsy in all cases. In 14
patients, the potential proliferative activity of the tumour was investigated by
(3H)thymidine in vitro binding and labelling index determination. Chorionic
gonadotropin, alpha-fetoprotein and embryonal carcinoma antigen were negative in
the cerebrospinal fluid of these patients. All but 1 patient underwent whole
brain radiotherapy. Clinical and neuroradiological follow-up ranged between 3 and
13 years (mean 8). Complete clinical and neuroradiological recovery was achieved
in all patients after treatment. Fatal recurrences owing to neuraxis
dissemination occurred in three cases. The labelling index in the whole series
ranged between 0.1 and 5% (median 2.5). Only syncytiotrophoblastic cells had
proliferative activity, while none of the lymphoid-like cells showed thymidine
labelling.
PMID- 9758298
TI - Diagnostic value of atypical lymphocytes in cerebrospinal fluid from adults with
enteroviral meningitis.
AB - We have noted two morphologically distinct types of atypical lymphocytes (AL) in
the cerebrospinal fluid (CSF) of adult patients with meningitis: one, which we
designate type-I AL, with multilobulated nuclei resembling those of the abnormal
cells in adult T-cell leukaemia (ATL); and another, type-II AL, characterized by
large lymphocytes with basophilic cytoplasm and nuclei containing coarse
chromatin. Type-I AL were detected in 25 of 39 patients (64%) with enteroviral
and in 11 of 109 (11%) with aseptic meningitis presumed to be caused by other
viruses, but not in meningitis resulting from Cryptococcus neofirmans (n = 14),
Mycobacterium tuberculosis (n = 19) or acute bacterial infection (n = 49). Type-I
AL were not seen in herpes zoster (n = 15) aseptic meningeal reactions (n = 15),
or in leptomeningeal carcinomatosis (n = 14). Type-II AL were often present in
meningitis of various aetiologies and in aseptic meningeal reactions, but not in
leptomeningeal carcinomatosis. The presence of type-I AL in the CSF was found to
be indicative of enteroviral meningitis with the highest predictive value (69%),
while type-II AL had a lower diagnostic positive predictive value in meningitis
of the five aetiologies above. Type-I AL immunostained for CD4, while type-II AL
were stained for CD8. The presence of type-I AL in CSF strongly suggests
enteroviral meningitis, which warrants careful follow-up without antifungal,
antituberculous or antibacterial agents. However, type-I AL, which are likely to
be virally transformed lymphocytes, must be distinguished from ATL cells, which
frequently involve the meninges.
PMID- 9758299
TI - Cerebral blood flow in spinocerebellar degenerations: a single photon emission
tomography study in 28 patients.
AB - We used single photon emission tomography to study regional cerebral perfusion in
patients with different forms of spinocerebellar degeneration: 6 patients with
Friedreich's ataxia (FA), 6 with early-onset cerebellar ataxia with retained
tendon reflexes (EOCA), 5 with autosomal dominant cerebellar ataxia type 1 (ADCA
I) and 11 with idiopathic late-onset cerebellar ataxia (ILOCA). The results were
related to clinical and magnetic resonance imaging (MRI) findings. Cerebellar
hypoperfusion was constant in ADCA I and frequent in patients with other
spinocerebellar degenerations. Brain stem hypoperfusion was constant in ADCA I,
frequent in ILOCA patients with pontocerebellar atrophy and absent in FA and
EOCA. FA and EOCA often showed a reduction in the parietotemporal cortex blood
flow, which was not related to cortical atrophy. ILOCA patients had an asymmetric
pattern in the temporal areas with decreased blood flow in the right side only.
Caudate hypoperfusion was found in ADCA I patients. Cerebral atrophy did not
account for changes in regional blood flow, which probably indicate early
involvement of cerebral structures.
PMID- 9758300
TI - Quantification of post-concussion symptoms 3 months after minor head injury in
100 consecutive patients.
AB - Post-concussion symptoms (PCS) (such as headaches, irritability, anxiety,
dizziness, fatigue and impaired concentration) are frequently experienced by
patients who have sustained a minor head injury (MHI). The post-concussion
syndrome has been defined as a clinical state where 3 or more symptoms persist
for more than 3 months. This report focuses on the quantification of PCS
according to the Rivermead Postconcussion Symptoms Questionnaire (RPQ). We
studied 100 consecutive patients with MHI and normal computed tomography of the
brain. At 3 months after injury, 62% reported the presence of one or more
symptoms, and 40% fulfilled the diagnostic criteria for post-concussion syndrome.
Patients with post-concussion syndrome had significantly (P < 0.001) higher RPQ
scores (mean 19.1, SD 11.9) than those without (mean 1.2, SD 1.8). Patients on
sick leave owing to the injury reported significantly (P = 0.05) higher RPQ
scores (mean 10.3, SD 13.2) than those not on sick leave (mean 5.5, SD 8.6). We
observed no association between age, gender, cause of injury, severity of injury,
duration of amnesia and RPQ score. RPQ score provides useful information about
the severity of PCS regardless of whether the diagnostic criteria for the post
concussion syndrome are met or not.
PMID- 9758302
TI - Acute pure motor neuropathy with antibodies to gangliosides in a patient with
multiple sclerosis.
PMID- 9758301
TI - Rapidly progressive multifocal motor neuropathy with phrenic nerve paralysis:
effect of nocturnal assisted ventilation.
PMID- 9758303
TI - Primary medullary haemorrhage with intractable hiccup.
PMID- 9758304
TI - Current and future perspectives on inhaled anesthetics.
AB - The discovery of ether anesthesia made modern surgery possible. Successive
improvements produced today's inhaled anesthetics, compounds that allow precise
control over the anesthetic state without compromising safety. Such control
extends to induction and maintenance of, and recovery from, anesthesia. The
greatest emphasis is on the last, particularly the rapid recovery obtained with
anesthetics with low solubility in blood and tissues. The lowest solubility is
produced by halogenation with fluoride to the exclusion of other halogens. The
safety of anesthesia has many components. Important among these is molecular
stability that permits elimination of the unchanged anesthetic molecule in
expired air and provides resistance to degradation by metabolism and by carbon
dioxide absorbents. Halogenation with fluorine produces more stable, safer
anesthetics. Greater stability, lower solubility, and rapid recovery can decrease
direct and indirect costs.
PMID- 9758305
TI - Perioperative hypertension.
AB - Increased activity or inadequate inhibition of the autonomic nervous system is
often the cause of perioperative hypertension. The goal of treatment is to
maintain an adequate balance between myocardial oxygen supply and demand. Newer
agents, such as nicardipine and fenoldopam, may offer potential advantages over
older agents. The cost:benefit ratio of therapy with these newer agents must also
be considered. Despite the fact that perioperative hypertension is aggressively
treated, there are no long-term, large-scale study data indicating that this
treatment affects long-term patient outcomes.
PMID- 9758306
TI - Levofloxacin, a second-generation fluoroquinolone.
AB - Levofloxacin, levo-isomer of the D,L-racemate ofloxacin, is a new fluoroquinolone
antibiotic approved for use in the United States in December 1996. It has an
extended spectrum of activity compared with older-generation fluoroquinolones
(ciprofloxacin, ofloxacin), with improved activity against gram-positive bacteria
and excellent activity against gram-negative bacteria and atypical organisms.
Although its activity against anaerobic organisms is improved over that of
earlier fluoroquinolones, levofloxacin should not be considered a first-line
anaerobic agent. It is available in an injectable form, as well as an oral
formulation with virtually 100% oral bioavailability. The plasma elimination half
life ranges from 6-8 hours in individuals with normal renal function.
Approximately 80% of drug is eliminated unchanged in urine through glomerular
filtration and tubular secretion. The pharmacokinetics are not appreciably
affected by age, gender, or race when differences in renal function and body mass
and composition are taken into account. Levofloxacin had impressive efficacy in
clinical studies of community-acquired pneumonia, acute bacterial exacerbations
of chronic bronchitis, acute sinusitis, skin and skin structure infections, and
complicated urinary tract infections and pyelonephritis. It is well tolerated;
its adverse event profile is similar to that of other fluoroquinolones, with
gastrointestinal and central nervous system effects reported most commonly. Drug
interactions are uncommon with levofloxacin; however, coadministration with
antacids or with other agents containing divalent or trivalent cations reduces
levofloxacin absorption. The agent should prove to be more effective than older
fluoroquinolones, especially for infections caused by pneumococci highly
resistant to penicillin.
PMID- 9758308
TI - Effect of blood glucose concentrations on the development of chronic
complications of diabetes mellitus.
AB - Diabetes is associated with increased risk of cardiovascular disease, coronary
heart disease, stroke, acute myocardial infarction, blindness, and renal failure.
Strategies to reduce their occurrence are an essential focus of patient care.
More than one pathogenic process is involved, and genetics influence the risk.
Hyperglycemia is a factor in the development of microvascular and possibly
macrovascular complications. Two possible mechanisms of glucose damage are
glycation of proteins and the polyol pathway. Research led to the identification
of drugs that block parts of the pathways. In clinical trials, intensive control
of blood glucose concentrations decreased the risk of microvascular
complications. Adverse effects associated with intensive therapy, however,
include hypoglycemia and weight gain.
PMID- 9758307
TI - Pharmacotherapy of primary obsessive-compulsive disorder: review of the
literature.
AB - Obsessive-compulsive disorder (OCD) is a chronic illness that affects 2-3% of
Americans during their lifetime. It is characterized by recurrent obtrusive
thoughts (obsessions) that compel patients to perform repetitive behaviors that
can be excessively time consuming and cause marked distress. More than 40
controlled trials have been published on the treatment of OCD. Of drugs available
to treat the disorder, serotonin reuptake inhibitors (SRIs) are most studied.
With SRIs, symptoms improve in 22-62% of patients, but complete remission is
rare. An agent is often selected based on side effects and patient tolerance,
since SRIs are all equally effective. If no response is seen with average
dosages, dosages should be increased to the maximum within 4-8 weeks from
starting treatment. In patients with partial response, the dosage should be
increased to the maximum by 5-9 weeks. Before determining the effectiveness of
therapy, a trial of 8-13 weeks is necessary.
PMID- 9758309
TI - The role of troglitazone in treating the insulin resistance syndrome.
AB - Insulin resistance is characterized by impaired responsiveness to endogenous or
exogenous insulin and often results in the insulin resistance syndrome, a
clustering of cardiovascular risk factors that includes abdominal obesity,
hypertension, dyslipidemia, glucose intolerance, and hyperinsulinemia. Although
the mechanism responsible for insulin resistance has not been completely defined,
it is likely due to defective insulin receptor signaling and results in decreased
use of glucose. Troglitazone, the first in a new class of drugs, directly
decreases insulin resistance by improving insulin-mediated glucose disposal and
reduces plasma insulin concentrations. Glycemic control achieved with
troglitazone monotherapy is equivalent to that with sulfonylurea and metformin,
and when combined with these agents offers additional plasma glucose reduction.
Studies are necessary to determine the effect of thiazolidinediones on morbidity
and mortality of patients with type 2 diabetes and insulin resistance.
PMID- 9758310
TI - Monoclonal antibodies in the treatment of steroid-resistant acute graft-versus
host disease.
AB - Acute graft-versus-host disease (GVHD) remains the major obstacle for successful
allogeneic bone marrow transplantation (BMT). The frequency of grade II or higher
acute GVHD ranges from 30-50% in human leukocyte antigen (HLA)-matched sibling
transplants and 50-80% in HLA-matched unrelated transplants. The mortality and
morbidity associated with this complication are substantial. Corticosteroid and
polyclonal antibodies such as antithymocyte globulin (ATG) have had little
success in treating the disease; however, advances have been made in hybridoma
technology and understanding its immunopathophysiology. Based on these new
insights, monoclonal antibodies, either murine or "humanized," were tested as
rescue treatment for acute GVHD in human trials. Complete response rates ranged
from 20-40%, with relapse occurring often. Side effects consisted of
constitutional symptoms such as fever, chills, hypotension, thrombocytopenia, and
leukopenia. Limitations of monoclonal antibody treatment included low response
rate and patient survival, high relapse rate, risk of infectious complication,
and leukemic relapse. Future study should focus not only on improved side effects
and efficacy of monoclonal antibodies but also on better patient survival.
PMID- 9758311
TI - Recombinant follicle-stimulating hormone: new biotechnology for infertility.
AB - The frequency of infertility in developed countries is approximately 8-10%. New
drugs are available for assisted reproduction techniques. Two recombinant
follicle-stimulating hormone (FSH) products, follitropin-beta (Follistim in the
United States, Puregon in Europe) and follitropin-alpha (Gonal-F), join compounds
derived through transfecting nonhuman cell lines with genetic material capable of
replicating identical amino acid sequences to human compounds. The cell line used
for recombinant (r)-FSH production is the Chinese hamster ovary (CHO).
Previously, the only agents that showed benefit in controlled ovulatory
stimulation were derived from the urine of menopausal women. Those compounds
contain additional substances, such as urinary proteins and various amounts of
luteininzing hormone. The amino acid sequence of r-FSH is identical to that of
human FSH, but the two recombinant products exist in many different isoforms and
differ from each other and from human FSH due to varied carbohydrate side chains.
Due to variation in the carbohydrate side chains, follitropin-beta in solution
has a higher pH than urine-derived FSH, which enhances receptor affinity and
therefore is a greater inducer of folliculogenesis. Follitropin-beta does not
cause endogenous production of anti-CHO or anti-FSH antibodies, and is well
tolerated.
PMID- 9758312
TI - Venous thromboembolism in multiple trauma patients.
AB - Thromboembolic complications are frequent in patients with multiple trauma. The
efficacy of unfractionated heparin for venous thrombosis prophylaxis has not been
established. Based on limited prospective data, low-molecular-weight heparin
appears to be more effective than unfractionated heparin and at least as
effective as compression devices for preventing thromboembolic complications in
these patients. Vena cava filters should be considered in high-risk patients who
cannot receive anticoagulant therapy, but long-term filter use without
concomitant anticoagulant therapy is associated with a substantial risk of
recurrent thromboembolism.
PMID- 9758313
TI - Restenosis, the Achilles' heel of coronary angioplasty.
AB - Coronary angioplasty is widely performed for the management of symptomatic
coronary artery disease. With improvements in technique, operator experience, and
tools, more complex lesions are being treated. Unfortunately, luminal renarrowing
continues to limit the long-term success of the procedure, resulting in the need
for repeat revascularization in approximately 30% of patients within 6 months. As
the pathophysiologic process of restenosis is better defined, various
pharmacologic and mechanical interventions have been tried to attenuate the
process. Some agents are antithrombotics, antiplatelets, angiotensin-converting
enzyme inhibitors, lipid-lowering drugs, and calcium channel blockers.
Improvement has been noted with the newer glycoprotein IIb- and IIIa-blocking
agents, mechanical stents, and radioactive materials. Whether these new compounds
will withstand the test of time is unknown.
PMID- 9758314
TI - Does aspirin interfere with the therapeutic efficacy of angiotensin-converting
enzyme inhibitors in hypertension or congestive heart failure?
AB - We conducted a MEDLINE search of published literature from 1966 to January 1998
regarding the impact of aspirin (ASA) on the therapeutic effect of angiotensin
converting enzyme (ACE) inhibitors in hypertension and congestive heart failure.
Selected references from these articles and results of recent clinical trials
were also included. By inhibiting cyclooxygenase, ASA may interfere with the
prostaglandin-mediated hemodynamic effects of ACE inhibitors. Although other
nonsteroidal antiinflammatory drugs may increase blood pressure in hypertensive
patients taking an ACE inhibitor, low-dosage (< or = 100 mg/day) ASA does not.
However, higher dosages of ASA may attenuate the benefits of ACE inhibitors in
patients with hypertension and/or congestive heart failure (CHF). Low-dosage ASA
appears to interact little with ACE inhibitors, whereas higher dosages may
produce a more significant interaction. Patients with CHF may also be more
susceptible to this interaction because of underlying disease.
PMID- 9758315
TI - Chest discomfort associated with liposomal amphotericin B: report of three cases
and review of the literature.
AB - Liposomal formulations of amphotericin B are designed to maintain therapeutic
efficacy of amphotericin B deoxycholate while reducing its associated toxicities.
In three patients chest discomfort occurred during planned 1-hour infusions of
liposomal amphotericin B (AmBisome) 3 mg/kg/day during an open-label trial. The
first patient experienced chest tightness and difficulty breathing and the second
had dyspnea and acute hypoxia, both within 10 minutes of the start of the
infusion. The third patient complained of chest pain 5 minutes after the start of
two infusions. All symptoms resolved on terminating therapy. Two patients were
later rechallenged with slower infusions and tolerated the drug well. A review of
the English-language literature revealed only two other case reports of infusion
related chest or pulmonary reactions with the drug, although similar reactions
were noted in several reports of clinical trials. Further review of the
literature revealed reports of chest and pulmonary adverse events with other
liposomal formulations of amphotericin B, liposomal daunorubicin, liposomal
doxorubicin, and liposomes. The pathophysiology of such reactions remains
unclear, and premedication with diphenhydramine did not completely prevent this
reaction in one of our patients. We recommend infusing liposomal amphotericin B
over at least 2 hours with careful monitoring for adverse reactions.
PMID- 9758316
TI - Alpha1-acid glycoprotein concentrations and cerebrospinal fluid drug distribution
after subarachnoid hemorrhage.
AB - STUDY OBJECTIVE: To test the hypothesis that changes in alpha1-acid glycoprotein
(AAG) concentration alter central nervous system (CNS) drug distribution after
subarachnoid hemorrhage. DESIGN: Two-phase, prospective study. SETTING:
University-associated medical center. PATIENTS: Twenty-one patients with
subarachnoid hemorrhage. INTERVENTION: In phase I, serum AAG concentrations of
patients with subarachnoid hemorrhage were measured serially and compared with
those in 21 controls undergoing elective neurosurgical procedures. In phase II,
nimodipine was the pharmacologic probe to determine the relationship between drug
distribution into the CNS and changes in AAG concentration. MEASUREMENTS AND MAIN
RESULTS: Serum and cerebrospinal fluid (CSF) samples were collected from patients
with subarachnoid hemorrhage treated with nimodipine and used to measure total
and unbound drug concentrations. Concentrations of AAG were 39% higher in
patients than in controls preoperatively. They decreased significantly by 24
hours after surgery in patients and increased in controls. In both groups the
concentrations were higher than reported normal values. During the period of
reduced AAG concentration, calculated unbound nimodipine concentrations were 3
fold higher (p<0.05) than at later periods, with a trend toward higher total
concentrations. Overall, mean CSF nimodipine concentration was 6.4% of mean serum
total concentration. The CSF concentrations decreased as AAG concentrations
increased, independent of serum concentrations (r = -0.52, p<0.02). CONCLUSION:
Concentrations of AAG change after subarachnoid hemorrhage and are transiently
influenced by surgery. Unbound drug concentration increases when AAG
concentrations decrease, whereas CSF concentrations decrease when AAG
concentrations increase. These preliminary findings suggest that changes in AAG
concentrations can alter unbound serum nimodipine concentrations and may affect
CSF drug distribution.
PMID- 9758317
TI - Comparison of bactericidal activities of intermittent and continuous infusion
dosing of vancomycin against methicillin-resistant Staphylococcus aureus and
Enterococcus faecalis.
AB - STUDY OBJECTIVE: To describe the pharmacokinetic profiles of vancomycin
administered by continuous infusion and intermittent dosing and compare the
duration of activity of the regimens. DESIGN: Randomized, open-label, crossover
study. SETTING: Clinical research center at an academic medical center. SUBJECTS:
Twelve healthy, nonpregnant volunteers age 27.6 +/- 2.3 years. INTERVENTION:
Subjects received the following intravenous vancomycin regimens: 1 g every 12
hours; 2 g continuous infusion over 24 hours; and 1 g continuous infusion over 24
hours. Dosages were administered with and without gentamicin 2 mg/kg.
MEASUREMENTS AND MAIN RESULTS: Serum samples were collected, drug concentrations
determined, and bactericidal activity measured against two isolates each of
methicillin-resistant Staphylococcus aureus and Enterococcus faecalis. Subjects
had poor tolerability for continuous infusions. Trough concentration for the
intermittent regimen was 5.5 +/- 1.9 mg/ml, and steady-state concentrations were
8.8 +/- 1.6 and 16.9 +/- 1.9 mg/ml for 1 and 2 g continuous infusions,
respectively. In general, all regimens provided bactericidal activity throughout
the study interval. Against one isolate of E. faecalis, 2 g continuous infusion
plus gentamicin provided cidal activity for a significantly greater percentage of
the dosing interval (p<0.001). CONCLUSION: Continuous infusion does not greatly
improve the activity of vancomycin and should not be routinely administered.
However, it may prove useful against isolates with reduced susceptibility to the
agent.
PMID- 9758318
TI - Evaluation of a rat model of valproate-induced obesity.
AB - Long-term treatment with the anticonvulsant valproate (VPA) leads to well
documented weight gain and obesity in humans. In an attempt to develop an animal
model of this condition, adult rats were given VPA 20 g/kg (high-dose) or 2 g/kg
(low-dose) in their daily feeding or orally 120 mg/kg body weight/day in two
divided doses, and food intake and body weight were assessed. Valproate resulted
in lower body weights in all protocols. Food intake was lower (p<0.001) for rats
receiving high-dose VPA than for controls. Feed efficiency (change in weight
divided by cumulative food intake for that period) was lower than that of
controls for both high (p<0.0001) and low doses (NS). Metabolic rate and physical
activity were not different between control and VPA animals, although decreased
food intake would be expected to decrease metabolic rate. Valproate failed to
produce obesity in rats in any treatment period. For reasons that are unclear,
rats do not appear to be suitable as a model to study this adverse side effect of
VPA in humans with epilepsy.
PMID- 9758319
TI - Vancomycin pharmacokinetics in neonates receiving extracorporeal membrane
oxygenation.
AB - Vancomycin is administered as both prophylaxis and treatment in neonates
receiving extracorporeal membrane oxygenation (ECMO), typically after surgery. An
open-label, retrospective study was conducted to determine dosing strategies in
all neonates who received vancomycin during ECMO and compare pharmacokinetic
values with those of matched controls not receiving ECMO. Fifteen neonates
receiving ECMO were given vancomycin infused into the circuit, with dosages based
on weight and gestational age. Blood for serum concentrations was drawn around
the third dose, for trough concentrations immediately before the dose, and for
peak concentrations 1 hour after infusion. Samples were analyzed by fluorescence
polarization immunoassay. The most frequent regimen for both groups (8 ECMO, 13
controls) was 10 mg/kg every 8 hours. It produced peak and trough concentrations
of 27.5 +/- 4.3 and 13.7 +/- 2.7 microg/ml, and 23.0 +/- 5.4 and 13.2 +/- 4.5
microg/ml, respectively. Pharmacokinetic analysis using a one-compartment model
revealed volume of distribution of 0.45 +/- 0.18 L/kg, half-life of 8.29 +/- 2.23
hours, and total body clearance of 0.65 +/- 0.28 ml/min/kg in ECMO recipients.
Volume of distribution and clearance were not significantly different in controls
(0.39 +/- 0.12 L/kg, 0.79 +/- 0.41 ml/min/kg), but half-life was shorter (6.53 +/
2.05 hrs, p = 0.02). Based on long volume of distribution in neonates receiving
ECMO, we recommend that empiric vancomycin regimens incorporate a longer dosing
interval than the 6-8 hours commonly recommended for term infants. The effects of
severity of illness on drug elimination require additional study.
PMID- 9758320
TI - Case-control study of amphotericin B in a triglyceride fat emulsion versus
conventional amphotericin B in patients with AIDS.
AB - We evaluated the efficacy and tolerability of amphotericin B triglyceride
emulsion in 16 patients with acquired immunodeficiency syndrome-related candidal
esophagitis and cryptococcosis, compared with standard amphotericin B in 24
patients. Compared with the conventional formulation, the fat emulsion was
administered in a significantly greater daily dose, and required shorter
induction period and infusion time (p<0.001-<0.03). Although the two drugs had
similar clinical and microbiologic efficacy, the fat emulsion had a better safety
profile with respect to frequency of flu-like symptoms, other local and systemic
adverse events, and treatment discontinuation (p<0.02-<0.05). Because it is
easily available and inexpensive, it may have a number of advantages over the
conventional formulation. Further similar comparisons are warranted, in addition
to investigations to assess whether reduced toxicity can be obtained with fat
emulsion without impairing (or possibly improving) the efficacy of this key
antifungal agent.
PMID- 9758321
TI - Clinical pharmacy services in hospitals educating pharmacy students.
AB - In 1995 we conducted a national survey of 1102 acute care hospitals in the United
States to determine types of clinical pharmacy services, patient-focused care,
and pharmaceutical care used to educate and train pharmacy students, and compared
outcomes with surveys in 1989 and 1992. Clinical pharmacy services offered in 50%
or more of Pharm.D.-affiliated hospitals (core services) were drug-use
evaluation, in-service education, pharmacokinetic consultations, adverse drug
reaction management, drug therapy monitoring, protocol management (most common
for aminoglycosides, nutrition, antibiotics, heparin, warfarin, theophylline),
nutrition team, and drug counseling. Comprehensive pharmaceutical care programs
were established in 64%, 42%, and 33% of Pharm.D., B.S., and nonteaching
hospitals, respectively. Patient-focused care programs were beginning or
established in 77%, 71%, and 60%, respectively. Pharmacists served as care team
leaders in 23% of hospitals affiliated with a college of pharmacy. Most common
ambulatory care clinics were oncology, anticoagulation, diabetes, geriatrics,
refill, and infectious diseases/HIV. For-profit hospitals rarely provided
education for pharmacy students. Thus patient-focused and comprehensive
pharmaceutical care programs exist according to a hospital's academic program
affiliation with Pharm.D. or B.S. degree program.
PMID- 9758322
TI - Cost avoidance, acceptance, and outcomes associated with a pharmacotherapy
consult clinic in a Veterans Affairs Medical Center.
AB - A pharmacist-directed pharmacotherapy consult clinic (PCC) was established in an
interdisciplinary primary care medicine continuity clinic. The pharmacist
initiated or modified patient care plans in collaboration with primary care
physicians and maintained care plans for 336 (32.8%) of 1023 patients enrolled in
the continuity clinic. Clinical outcomes were positive in 88.3% of patient
visits, with 95.7% attendance at the PCC clinic and 95% physician acceptance of
pharmacist recommendations. Average reductions of 2.4 prescriptions/patient and
6.9 doses/day were achieved. Actual and potential cost avoidance totaled
$54,730.56, with actual and potential savings realized compared with dollars
spent at a ratio of 5.8:1. The pharmacist provided value-added services and
contributed to decreased costs associated with care.
PMID- 9758323
TI - Frequency of hospitalization after exposure to known drug-drug interactions in a
Medicaid population.
AB - A matched-pair case-control analysis of Medicaid claims was performed to
determine the risks of hospitalization associated with drug-drug interactions.
Patients were hospitalized and controls were not. They were randomly matched
based on contemporaneous eligibility for Medicaid benefits. Odds ratios for
hospitalization in patients exposed to known drug-drug interactions were compared
with those in patients exposed to one of the interacting agents. When confidence
intervals did not overlap, the odds ratio was considered to be significantly
increased. Odds ratios were significantly increased for many interacting drug
pairs, and were associated with commonly recognized interactions as well as less
widely recognized ones. Cimetidine interactions achieved significance only with
theophylline. In the Medicaid population, exposure to a number of drug-drug
interactions was associated with a significantly increased risk of
hospitalization.
PMID- 9758324
TI - Postmarketing surveillance of the safety of cyclic etidronate.
AB - To evaluate the safety of cyclic etidronate in routine clinical practice, we
obtained information from 550 general practices in the United Kingdom that
provide the medical records to the General Practice Research Database. A group of
7977 patients taking cyclic etidronate and two age-, gender-, and practice
matched control groups, one with osteoporosis and one without, were analyzed. For
the group taking cyclic etidronate, the average age was 71.6 years and follow-up
was 10,328 person-years. Conditions that do not induce osteoporosis generally
occurred in these patients at a rate comparable to that in the control groups.
The incidence of osteomalacia was low and comparable between patients taking
cyclic etidronate and controls with osteoporosis. No medically significant
increases in frequency were observed among patients taking cyclic etidronate for
a broad group of diseases that may potentially be induced by exposure to the
drug. These data support the favorable risk:benefit ratio of cyclic etidronate.
PMID- 9758325
TI - Seizures in patients receiving concomitant antimuscarinics and
acetylcholinesterase inhibitor.
AB - Seizures occurred in two patients with probable Alzheimer's disease who were
receiving long-term treatment with metrifonate, an irreversible
acetylcholinesterase inhibitor. In both patients seizures were associated with
discontinuation of short-term agents with high antimuscarinic properties. Hence,
abrupt discontinuation of antimuscarinics or anticholinergics with high
antimuscarinic properties in patients receiving long-term acetylcholinesterase
inhibition therapy may be associated with a reduction of seizure threshold. With
increasing administration of acetylcholinesterase inhibitors for patients with
Alzheimer's disease, practitioners should be aware of the potential for drug-drug
interactions and other complications. In general, it is good medical practice to
avoid concomitant administration with centrally acting anticholinergic agents.
PMID- 9758326
TI - Another report of adverse reactions to immediate-release nifedipine.
AB - Numerous case reports in the literature describe adverse drug events associated
with immediate-release nifedipine (IRN). In addition, several publications
alerted health care professionals regarding the agent. However, it is still
administered, and adverse reactions are still reported. Our patient suffered IRN
induced hypotension, myocardial ischemia, and mental status changes. We recommend
that the use of IRN in treatment of hypertension should be either totally
prohibited or severely restricted. The product should not be readily available
for indiscriminate administration. Also, continuing education and training are
required to alert all health care professionals to the serious dangers associated
with this drug.
PMID- 9758328
TI - Molecular characterization of a novel family of low voltage-activated, T-type,
calcium channels.
AB - Low voltage-activated, T-type, calcium channels are thought to be involved in
pacemaker activity, low threshold Ca2+ spikes, neuronal oscillations and
resonance, and rebound burst firing. Mutations in T-type channel genes may be a
contributing factor to neurological and cardiovascular disorders, such as
epilepsy, arrhythmia, and hypertension. Due to the lack of selective blockers,
little is known about their structure or molecular biology. This review discusses
our recent findings on the cloning, chromosomal localization, and functional
expression, of two novel channels, alpha1G and alpha1H. The biophysical
properties of these cloned channels (distinctive voltage dependence, kinetics,
and single channel conductance) demonstrates that these channels are members of
the T-type Ca2+ channel family.
PMID- 9758327
TI - Overview of voltage-dependent calcium channels.
AB - Voltage-dependent calcium channels couple electrical signals to cellular
responses in excitable cells. Calcium channels are crucial for excitation
secretion coupling in neurons and endocrine cells, and excitation-contraction
coupling in muscle. Several pharmacologically and kinetically distinct calcium
channel types have been identified at the electrophysiological and molecular
levels. This review summarizes the basic properties of voltage-dependent calcium
channels, including mechanisms of ion permeation and block, gating kinetics, and
modulation by G proteins and second messengers.
PMID- 9758329
TI - Molecular basis of drug interaction with L-type Ca2+ channels.
AB - Different types of voltage-gated Ca2+ channels exist in the plasma membrane of
electrically excitable cells. By controlling depolarization-induced Ca2+ entry
into cells they serve important physiological functions, such as excitation
contraction coupling, neurotransmitter and hormone secretion, and neuronal
plasticity. Their function is fine-tuned by a variety of modulators, such as
enzymes and G-proteins. Block of so-called L-type Ca2+ channels by drugs is
exploited as a therapeutic principle to treat cardiovascular disorders, such as
hypertension. More recently, block of so-called non-L-type Ca2+ channels was
found to exert therapeutic effects in the treatment of severe pain and ischemic
stroke. As the subunits of different Ca2+ channel types have been cloned, the
modulatory sites for enzymes, G-proteins, and drugs can now be determined using
molecular engineering and heterologous expression. Here we summarize recent work
that has allowed us to determine the sites of action of L-type Ca2+ channel
modulators. Together with previous biochemical, electrophysiological, and drug
binding data these results provide exciting insight into the molecular
pharmacology of this voltage-gated Ca2+ channel family.
PMID- 9758330
TI - Physical link and functional coupling of presynaptic calcium channels and the
synaptic vesicle docking/fusion machinery.
AB - N- and P/Q-type calcium channels are localized in high density in presynaptic
nerve terminals and are crucial elements in neuronal excitation-secretion
coupling. In addition to mediating Ca2+ entry to initiate transmitter release,
they are thought to interact directly with proteins of the synaptic vesicle
docking/fusion machinery. As outlined in the preceding article, these calcium
channels can be purified from brain as a complex with SNARE proteins which are
involved in exocytosis. In addition, N-type and P/Q-type calcium channels are co
localized with syntaxin in high-density clusters in nerve terminals. Here we
review the role of the synaptic protein interaction (synprint) sites in the
intracellular loop II-III (L(II-III)) of both alpha1B and alpha1A subunits of N
type and P/Q-type calcium channels, which bind to syntaxin, SNAP-25, and
synaptotagmin. Calcium has a biphasic effect on the interactions of N-type
calcium channels with SNARE complexes, stimulating optimal binding in the range
of 10-20 microM. PKC or CaM KII phosphorylation of the N-type synprint peptide
inhibits interactions with native brain SNARE complexes containing syntaxin and
SNAP-25. Introduction of the synprint peptides into presynaptic superior cervical
ganglion neurons reversibly inhibits EPSPs from synchronous transmitter release
by 42%. At physiological Ca2+ concentrations, synprint peptides cause an
approximate 25% reduction in transmitter release of injected frog neuromuscular
junction in cultures, consistent with detachment of 70% of the docked vesicles
from calcium channels based on a theoretical model. Together, these studies
suggest that presynaptic calcium channels not only provide the calcium signal
required by the exocytotic machinery, but also contain structural elements that
are integral to vesicle docking, priming, and fusion processes.
PMID- 9758331
TI - Interactions between presynaptic calcium channels and proteins implicated in
synaptic vesicle trafficking and exocytosis.
AB - Monoclonal antibodies were generated by immunizing mice with chick brain synaptic
membranes and screening for immunoprecipitation of solubilized omega conotoxin
GVIA receptors (N-type calcium channels). Antibodies against two synaptic
proteins (p35--syntaxin 1 and p58--synaptotagmin) were produced and used to
purify and characterize a ternary complex containing N-type channels associated
with these two proteins. These results provided the first evidence for a specific
interaction between presynaptic calcium channels and SNARE proteins involved in
synaptic vesicle docking and calcium-dependent exocytosis. Immunoprecipitation
experiments supported the conclusion that syntaxin 1/SNAP-25/VAMP/synaptotagmin I
or II complexes associate with N-type, P/Q-type, but not L-type calcium channels
from rat brain nerve terminals. Immunofluorescent confocal microscopy at the frog
neuromuscular junction was consistent with the co-localization of syntaxin 1,
SNAP-25, and calcium channels, all of which are predominantly expressed at active
zones of the presynaptic plasma membrane facing post-synaptic folds rich in
acetylcholine receptors. The interaction of proteins implicated in calcium
dependent exocytosis with presynaptic calcium channels may locate the sensor(s)
that trigger vesicle fusion within a microdomain of calcium entry.
PMID- 9758333
TI - Post-translational modifications of beta subunits of voltage-dependent calcium
channels.
AB - Different post-translational modifications of Ca channel beta subunits have been
identified. Recent studies have characterized the palmitoylation of the Ca
channel beta2a subunit, as well as one effect of this modification on channel
function. The potential importance of palmitoylation on other channel properties
is discussed. Other studies have addressed the role of phosphorylation of beta
subunits in the regulation of voltage-dependent Ca channels. Phosphorylation of
beta subunits by second messenger-activated protein kinases, as well as by
unidentified protein kinases, may affect interactions between channel subunits
and other aspects of channel function. The differential modification of Ca
channel beta subunit isoforms by post-translational events likely results in
diversely regulated channels with unique properties.
PMID- 9758332
TI - Structures and functions of calcium channel beta subunits.
AB - Calcium channel beta subunits have profound effects on how alpha1 subunits
perform. In this article we summarize our present knowledge of the primary
structures of beta subunits as deduced from cDNAs and illustrate their different
properties. Upon co-expression with alpha1 subunits, the effects of beta subunits
vary somewhat between L-type and non-L-type channels mostly because the two types
of channels have different responses to voltage which are affected by beta
subunits, such as long-lasting prepulse facilitation of alpha1C (absent in
alpha1E) and inhibition by G protein betagamma dimer of alpha1E, absent in
alpha1C. One beta subunit, a brain beta2a splice variant that is palmitoylated,
has several effects not seen with any of the others, and these are due to
palmitoylation. We also illustrate the finding that functional expression of
alpha1 in oocytes requires a beta subunit even if the final channel shows no
evidence for its presence. We propose two structural models for Ca2+ channels to
account for "alpha1 alone" channels seen in cells with limited beta subunit
expression. In one model, beta dissociates from the mature alpha1 after proper
folding and membrane insertion. Regulated channels seen upon co-expression of
high levels of beta would then have subunit composition alpha1beta. In the other
model, the "chaperoning" beta remains associated with the mature channel and
"alpha1 alone" channels would in fact be alpha1beta channels. Upon co-expression
of high levels of beta the regulated channels would have composition
[alpha1beta]beta.
PMID- 9758334
TI - Genetic analysis of voltage-dependent calcium channels.
AB - Molecular cloning of calcium channel subunit genes has identified an unexpectedly
large number of genes and splicing variants, and a central problem of calcium
channel biology is to now understand the functional significance of this genetic
complexity. While electrophyisological, pharmacological, and molecular cloning
techniques are providing one level of understanding, a complete understanding
will require many additional kinds of studies, including genetic studies done in
intact animals. In this regard, an intriguing variety of episodic diseases have
recently been identified that result from defects in calcium channel genes. A
study of these diseases illustrates the kind of insights into calcium channel
function that can be expected from this method of inquiry.
PMID- 9758335
TI - Metabolism and trafficking of N-type voltage-operated calcium channels in
neurosecretory cells.
AB - The N-type voltage-operated calcium channel has been characterized over the years
as a high-threshold channel, with variable inactivation kinetics, and a unique
ability to bind with high affinity and specificity omega-conotoxin GVIA and
related toxins. This channel is particularly expressed in some neurons and
endocrine cells, where it participates in several calcium-dependent processes,
including secretion. Omega-conotoxin GVIA was instrumental not only for the
biophysical and pharmacological characterization of N-type channels but also for
the development of in vitro assays for studying N-type VOCC subcellular
localization, biosynthesis, turnover, as well as short-and long-term regulation
of its expression. We here summarize our studies on N-type VOCC expression in
neurosecretory cells, with a major emphasis on recent data demonstrating the
presence of N-type channels in intracellular secretory organelles and their
recruitment to the cell surface during regulated exocytosis.
PMID- 9758337
TI - Allogeneic transplantation of selected CD34+ cells from peripheral blood:
experience of 62 cases using immunoadsorption or immunomagnetic technique.
Spanish Group of Allo-PBT.
AB - The objective of this study was to analyze CD34+ cell recovery and T cell
depletion (TCD) achieved in CD34+ cell grafts using either immunoadsorption or
immunomagnetic methods applied to leukapheresis products from healthy donors. We
also wanted to determine the kinetics of engraftment and incidence and severity
of graft-versus-host disease (GVHD) after allogeneic transplantation of selected
CD34+ cells. HLA-identical sibling donors received G-CSF. After leukapheresis,
peripheral blood progenitor cells were selected using immunoadsorption (Ceprate
SC) (n = 38) or immunomagnetic (Isolex 300) (n = 24) methods. Sixty-two patients,
with a median age of 42 years (range 17-60) diagnosed with hematological
malignancies were conditioned with either cyclophosphamide and total body
irradiation (n = 43) or busulphan and cyclophosphamide (n = 19). GVHD prophylaxis
consisted of cyclosporin A (CsA) and prednisone (n = 48), CsA alone (n = 11) and
CsA and methotrexate (n = 3). The median yield and purity of CD34+ cells after
the procedure was 65 and 66% with immunoadsorption, and 48 and 86% with
immunomagnetic method, respectively. The median number (range) of CD34+ cells
infused into the patients was 3.5 x 10(6)/kg (1-9.6). The median number (range)
of CD3+ cells administered was 0.4 x 10(6)/kg (0.01-2) using immunoadsorption and
0.14 x 10(6)/kg (0.03-2.5) using immunomagnetic methods. Neutrophil recovery >500
and >1000/microl was achieved at a median (range) of 13 days (8-22) and 14 days
(9-31), respectively. Platelets recovered to >20000 and >50000/microl at a median
(range) of 13 days (0-128) and 18 days (0-180), respectively. Two patients
developed graft failure. Acute GVHD in patients at risk was clinical grade 0 (n =
43), I (n = 8), II (n = 4) and III (n = 1). No patient developed acute GVHD grade
IV. Chronic GVHD was limited in two cases and extensive in four cases. The
actuarial probability of acute GVHD II-IV was 10% (95% CI, 1-19%), and of
extensive chronic GVHD was 12% (95% CI, 11-13%). The cumulative incidence of
transplant-related mortality was 12.6%, and this figure was 9% at 6 months. In
conclusion, with the immunomagnetic procedure, a lower recovery and higher purity
of CD34+ cells, and stronger TCD is obtained as compared to immunoadsorption (P =
0.008, P < 0.0001 and P = 0.0002, respectively). Our results also indicate that
allogeneic transplantation of selected CD34+ cells is associated with a very
rapid engraftment and with a low incidence of severe GVHD.
PMID- 9758336
TI - Differential expression and association of calcium channel subunits in
development and disease.
AB - Voltage-gated calcium channels (VDCC) are essential to neuronal maturation and
differentiation. It is believed that important signaling information is encoded
by VDCC-mediated calcium influx that has both spatial and temporal components.
VDCC are multimeric complexes comprised of a pore-forming alpha1 subunit and
auxiliary beta and alpha2/delta subunits. Changes in the fractional contribution
of distinct calcium conductances to the total calcium current have been noted in
developing and differentiating neurons. These changes are anticipated to reflect
the differential expression and localization of the pore-forming alpha1 subunits.
However, as in vitro studies have established that beta regulates the channel
properties and targeting of alpha1, attention has been directed toward the
developmental expression and assembly of beta isoforms. Recently, changes in the
beta component of the omega-conotoxin GVIA (CTX)-sensitive N-type VDCC have
indicated differential assembly of alpha1B with beta in postnatal rat brain. In
addition, unique properties of beta4 have been noted with respect to its temporal
pattern of expression and incorporation into N-type VDCC complexes. Therefore,
the expression and assembly of specific alpha1/beta complexes may reflect an
elaborate cellular strategy for regulating VDCC diversity. The importance of
these developmental findings is bolstered by a recent study which identified
mutations in the beta4 as the molecular defect in the mutant epileptic mouse
(lethargic; lh/lh). As beta4 is normally expressed in both forebrain and
cerebellum, one may consider the impact of the loss of beta4 upon VDCC assembly
and activity. The importance of the beta1b and beta4 isoforms to calcium channel
maturation and assembly is discussed.
PMID- 9758339
TI - Phase II study of high-dose thiotepa and hematopoietic stem cell transplantation
in children with solid tumors.
AB - From 1987 to 1995, 22 children with refractory solid tumors entered a phase II
study of high-dose thiotepa (HDT) (900 mg/m2) followed by stem cell
transplantation (SCT) in the Pediatrics Department of the Institut Gustave
Roussy. Tumor types were rhabdomyosarcoma (eight), osteosarcoma (seven),
neuroblastoma (three), Ewing's sarcoma (three) and Burkitt's lymphoma (one).
Before HDT, all had been extensively treated with conventional chemotherapy,
surgical resection of the primary tumor (13/22) and of metastases (6/22), and
radiotherapy of the primary tumor in three patients. All had measurable disease,
at the site of the primary tumor (3 patients), of the metastases (9 patients) or
both (10 patients). Toxicity from the HDT was severe but acceptable. No toxicity
related death occurred. The median duration of neutropenia and thrombocytopenia
was 18 days (5-37) and 30 days (7-377), respectively. Septicemia was documented
in four patients. Severe diarrhea was observed in seven patients. Mild hepatic
toxicity occurred 18 times. No CR and 11/22 PR were documented: osteosarcoma 4/7,
rhabdomyosarcoma 4/8, Ewing's sarcoma 2/3; 1/1 Burkitt's lymphoma progressed. We
conclude that at a dose of 900 mg/m2 followed by SCT support in these heavily
pretreated children, the main toxicity induced by thiotepa was digestive. The
response rate observed, especially in sarcoma, is particularly encouraging.
Thiotepa should be further evaluated in HDC regimens either in combination with
other alkylating agents or in rapidly cycled courses of HDC with SCT.
PMID- 9758338
TI - A high resolution HLA class I and class II matching method for bone marrow donor
selection.
AB - HLA matching in bone marrow transplantation has an important role in determining
successful outcome. However HLA typing of both potential related and unrelated
donors can be both time-consuming and laborious, and does not always resolve
accurately the true level of histocompatibility. We have utilised a method,
reference strand mediated conformation analysis (RSCA), which is technically
simple and allows high resolution matching for all HLA loci, for the typing of 48
patients and their potential 120 donors. The results indicate that RSCA can
detect many mismatches that are not routinely identified by conventional HLA
typing methods. In addition, RSCA can be applied for the simultaneous analysis of
multiple potential BM donor samples in order to quickly identify the best match
for each patient.
PMID- 9758340
TI - Low incidence of acute graft-versus-host disease and recurrent leukaemia in
patients undergoing allogeneic haemopoietic stem cell transplantation from
sibling donors with methotrexate and dose-monitored cyclosporin A prophylaxis.
AB - One of the major aims of allogeneic haemopoietic stem cell transplantation has
been the effective suppression of graft-versus-host disease (GVHD) without loss
of a graft-versus-leukaemia effect. For GVHD suppression, one of the most
frequently used regimens has been the combination of cyclosporin (CsA) and a
short course of methotrexate (MTX) although the optimal usage of these agents
remains unclear. Here, we report the results of 55 patients with standard risk
leukaemia who have undergone allogeneic transplantation using either bone marrow
(n = 48) or G-CSF mobilised peripheral blood stem cells (n = 7) using CsA and MTX
for GVHD prophylaxis where the dosage of CsA was regularly adjusted to maintain a
trough whole blood level of 95-205 ng/ml for the first 50 days post-transplant.
To achieve this level of CsA in the immediate post-transplant period, over 40% of
patients required dose adjustments of CsA as a result of sub-therapeutic levels
on day +1 post-transplant. The achievement of CsA levels within the therapeutic
range was expedited following the introduction of a sliding scale for dose
adjustment. With this regimen we have observed a low incidence of acute GVHD with
only 11% of patients developing > or =grade II disease. With a median follow-up
of 66 months (range 8-132) the probability of relapse is only 6.6%. The disease
free survival probability for all patients was 72% at 5 years. These results
demonstrate that effective GVHD prevention with CsA and MTX can be achieved
without a high risk of recurrent leukaemia provided that rapid attainment of
therapeutic CsA levels is achieved and maintenance within a low therapeutic range
may help to maximise this effect.
PMID- 9758341
TI - Variables associated with the platelet count 6 weeks after autologous peripheral
blood progenitor cell transplantation.
AB - While abundant data exist documenting variables associated with early platelet
engraftment after autologous PBPC transplantation, data concerning later
sustained platelet engraftment is sparse. We retrospectively examined a series of
80 patients undergoing autologous PBPC transplantation with respect to their
platelet count 6 weeks after transplant. Underlying diagnoses included breast
cancer (n = 33), non-Hodgkin's lymphoma (n = 32), Hodgkin's disease (n = 9), and
other hematologic malignancies (n = 6). Patients received G-CSF for PBPC
mobilization and collected a target threshold number of 2.0 x 10(6) CD34+ cells
per kilogram. A univariate analysis revealed that a diagnosis of breast cancer,
fewer courses of prior chemotherapy, younger age and complete remission were
associated with a higher 6-week platelet count. Additionally, the ability to
collect the threshold number of CD34+ with fewer sessions of leukapheresis was
also associated with a higher 6-week platelet count. The platelet count and the
white blood cell count at the initiation of PBPC collection was also associated
with a higher 6-week platelet count. A multivariate analysis revealed a higher
platelet count on the first day of pheresis, fewer phereses required to collect 2
x 10(6) CD34+ cells per kilogram, and a diagnosis of breast cancer were all
associated with a higher 6-week post-transplant platelet count. Seven patients
failed to reach a 6-week platelet count of 30 x 10(9)/l and an additional five
patients had a platelet count of 30-50 x 10(9)/l. We conclude that underlying
clinical characteristics, as well as hematologic variables at the time of PBPC
collection, influence later, sustained platelet engraftment. A percentage of
patients have poor sustained platelet engraftment and may be candidates for new
cytokines that specifically target megakaryocyte growth and development.
PMID- 9758343
TI - Bone marrow transplantation in children: consequences for renal function shortly
after and 1 year post-BMT.
AB - The aim of this study was to investigate the effect of a bone marrow
transplantation (BMT) on renal function in children. In a 5-year period, 142
children received a BMT at the Department of Pediatrics of the University
Hospital Leiden. The study was performed retrospectively using the estimated
glomerular filtration rate before and 1 year after BMT, and weekly measurements
of serum creatinine during the first 3 months after BMT for assessment of renal
function. Patient characteristics (sex, age, diagnosis), conditioning regimen,
type of BMT, major complications (sepsis, veno-occlusive disease and graft-versus
host disease (GVHD)) and the use of nephrotoxic medication were listed. In the
first 3 months after BMT 17 (12%) patients died, 13 from transplant-related
complications other than renal failure and four from relapse of the disease.
Forty-eight children (34%) had a period with acute renal insufficiency. A high
pre-BMT serum creatinine, transplantation with either a non-HLA-identical related
or a matched unrelated donor were risk factors for acute renal insufficiency
after BMT. Sepsis and the use of intravenous vancomycin were risk factors for
acute renal insufficiency only for patients with a high pre-BMT serum creatinine.
GVHD seemed to have a beneficial effect on renal function of BMT recipients. One
year after BMT a total of 35 (25%) patients had died, 16 from transplant-related
complications and 19 from relapse of the disease; another 17 patients could not
be evaluated. Twenty-five of 90 evaluable children (28%) had chronic renal
insufficiency. Chronic renal insufficiency 1 year after BMT was correlated with a
high serum creatinine in the first 3 months after BMT. None of the children of
this retrospective study on renal function after BMT needed dialysis.
PMID- 9758342
TI - Use of the polymerase chain reaction and direct sequencing analysis to detect
cells with the t(14;18) in autologous bone marrow from patients with follicular
lymphoma, before and after in vitro treatment.
AB - Between August 1993 and February 1994, 25 patients with follicular or transformed
follicular lymphoma had bone marrow harvested at St Bartholomew's Hospital (SBH)
with a view to proceeding to high-dose treatment comprising: cyclophosphamide 60
mg/kg x 2 and total body irradiation, 200 cGy x 6, supported by autologous bone
marrow transplantation (ABMT). The marrow mononuclear cell fraction was treated
in vitro with four anti-B cell antibodies and baby rabbit complement. The aim of
this study was to determine whether in vitro treatment of the marrow could remove
morphologically undetectable lymphoma cells. PCR analysis for the t(14;18) was
used to determine the presence or absence of lymphoma. At the time of the bone
marrow harvest, 21/25 bone marrow samples were positive for the t(14;18), in
15/22 patients, the rearrangement could also be demonstrated in peripheral blood.
After in vitro treatment, 18/21 samples (86%) remained 'PCR positive'. Sequence
analysis of the t(14;18) PCR products was performed on the latter and on lymph
node biopsy material taken at diagnosis from 12 patients. The same t(14;18)
sequences were found in the bone marrow harvest samples as in the patients'
original biopsies. These results suggest that this form of in vitro treatment
does not completely eradicate the t(14;18) bearing clone. New and better methods
need to be developed.
PMID- 9758344
TI - Avascular necrosis of bone following allogeneic stem cell transplantation: MR
screening and therapeutic options.
AB - With improvement in long-term survival after allogeneic stem cell
transplantation, late complications with significant morbidity are of increasing
importance. We retrospectively analysed 272 recipients of an allogeneic stem cell
transplant for the development of osteonecrosis. The incidence among allograft
recipients was 6.3% (17/272) for the whole patient population, and 11.8% (17/144)
for long-term survivors. All patients were treated with high-dose prednisolone,
16 for severe acute or extensive chronic graft-versus-host disease (GVHD) and one
patient for graft rejection. The mean age at time of diagnosis was 33 years
(range 16-45) and the mean time from transplant to diagnosis of osteonecrosis was
13 months. Osteonecrosis was diagnosed by magnetic resonance (MR) imaging, which
allows early detection of osteonecrosis and assessment of stage. At the time of
diagnosis, eight patients had stage I, three patients stage II, three patients
stage III and three patients stage IV osteonecrosis according to MR criteria. All
but one patient had involvement of the femoral head. The median total dosage of
prednisolone at the time of diagnosis was 189 mg/kg (single manifestation 150
mg/kg; multiple manifestations 313 mg/kg) with a total range of 13-555 mg/kg. Six
patients were treated by conservative means, 77 patients underwent surgery (three
core decompression, eight joint replacement). MR screening of patients receiving
high-dose steroids might help to detect osteonecrosis at an early stage and thus
prevent progression by early intervention, for example, by core decompression.
PMID- 9758345
TI - Ultrasound-guided fine needle cutting biopsy for the characterization of diffuse
liver diseases in bone marrow transplant patients.
AB - Liver disease is a frequent complication in bone marrow transplant recipients and
may occur early or late in the post-transplant period. Using ultrasound-guided
fine needle (1.2 mm, 18 G) cutting biopsy, we studied six patients with undefined
late post-BMT liver disease. No procedure-related complications occurred and all
liver biopsies were informative, leading to changes in therapeutic approach. In
our small series, the most frequent cause of hepatic damage was drug toxicity. US
guided fine needle cutting biopsy is a useful and easy tool for the work-up of
unexplained post-BMT liver disease.
PMID- 9758346
TI - Transfusion support using filtered unscreened blood products for cytomegalovirus
negative allogeneic marrow transplant recipients.
AB - It has been suggested that leukoreduced unscreened blood products can be used as
an alternative to components from cytomegalovirus (CMV)-seronegative donors in
order to prevent transmission of CMV from transfusions for CMV-seronegative
marrow transplant recipients with CMV-seronegative donors, but confirmatory data
are lacking. A retrospective chart review was undertaken for patients undergoing
allogeneic transplantation over a 4-year period during which blood products were
filtered for CMV-seronegative patients with CMV-seronegative donors when CMV
seronegative components were not available. Forty-five CMV-seronegative patient
donor pairs were identified. Only one patient developed CMV disease (pneumonia)
and no other patients developed an infection. In this group of patients, the rate
of CMV infection was 2.7% (95% CI, 0-8%) by life-table analysis. We conclude that
filtered unscreened blood products as partial transfusion support for CMV
seronegative marrow transplant recipients were associated with a low incidence of
CMV infection, justifying further evaluation of filtered blood products as total
transfusion support for this patient population. However, since CMV infections
still occur, continued surveillance by periodic culture or other techniques is
warranted.
PMID- 9758348
TI - Hyperbaric oxygen in the treatment of refractory haemorrhagic cystitis.
AB - Haemorrhagic cystitis is a common and often debilitating complication of
chemotherapy for which treatment is frequently unsatisfactory. With over 80 cases
reported of radiation-induced cystitis treated successfully with hyperbaric
oxygen, attention is now turning to the treatment of chemotherapeutic agent
induced cystitis. We report a case of haemorrhagic cystitis occurring after
autologous peripheral blood stem cell transplantation for multiple myeloma. The
patient had received cyclophosphamide and busulfan and had BK and adenoviruria.
The haemorrhage was refractory to multiple conventional treatments but resolved
after a course of hyperbaric oxygen.
PMID- 9758347
TI - Treatment of relapse after allogeneic bone marrow transplantation with
unmanipulated G-CSF-mobilized peripheral blood stem cell preparation.
AB - Donor lymphocyte infusions (DLI) are an effective treatment of leukemia relapse
after allogeneic bone marrow transplantation. Undesired side-effects are the
development of graft-versus-host disease (GVHD) and the occurrence of
pancytopenia in some patients. In a pilot study, we investigated if unmanipulated
G-CSF-mobilized peripheral blood stem cells which naturally contain large numbers
of T lymphocytes (D-PBSC/LI) would be equally effective or even superior than DLI
in generating a graft-versus-leukemia reaction (GVL) but could mitigate or
prevent the development of pancytopenia. We treated 12 patients with CML chronic
phase (n = 5), CML blast crisis (n = 2), AML (n = 2), ALL (n = 1), CLL (n = 1)
and multiple myeloma (n = 1). In five patients with acute leukemia or CML blast
crisis D-PBSC/LI followed intensive chemotherapy (group A), in seven patients D
PBSC/LI were given without any prior chemotherapy (group B). In group A two
patients were evaluable for hematologic toxicity. Leukopenia <1000/microl lasted
for 10 and 19 days, and thrombocytopenia <20,000/microl for 11 and 13 days,
respectively. In group B leukopenia <1000/microl and thrombocytopenia
<20,000/microl was observed in only one patient. Moderate cytopenia developed in
four of five evaluable patients. A complete remission could be achieved in all
seven patients with CML who all developed acute and/or chronic GVHD. None of the
remaining five patients achieved a complete remission despite acute and/or
chronic GVHD in two of them. Four patients died from disease progression, one
patient from a secondary lymphoma, and one patient as a result of uncontrolled
GVHD. In conclusion, D-PBSC/LI is effective in inducing GVL reaction but it does
not prevent pancytopenia in each case. It remains unclear if it mitigates the
incidence and severity of pancytopenia.
PMID- 9758349
TI - Acyclovir-resistant herpes simplex virus infections in a bone marrow transplant
population.
AB - Over a 3-month period, four patients who had received unrelated donor (UD) bone
marrow transplants (BMT) presented with severe mucocutaneous herpes simplex virus
(HSV) infection while receiving acyclovir (ACV) prophylaxis. Sensitivity testing
of the isolates revealed three to be acyclovir-resistant and in one patient the
infection was also characterised by a marked failure to respond to foscarnet
(phosphonoformic acid). The emergence of ACV-resistant HSV infections in
themselves is a new and challenging problem, and yet a far greater problem will
become evident if these infections develop resistance to non thymidine kinase
dependent therapy.
PMID- 9758350
TI - Total body irradiation and cyclophosphamide is a conditioning regimen for
unrelated bone marrow transplantation in a patient with chronic myelogenous
leukemia and renal failure on hemodialysis.
AB - Five years after the diagnosis of Ph chromosome-positive chronic myeloid leukemia
(CML) a 31-year-old patient developed malignant nephrosclerosis with renal
failure. He then underwent an allogeneic unrelated BMT in first chronic phase
CML. The preparative regimen consisted of fractionated total body irradiation
(TBI) and cyclophosphamide (CY). We studied the pharmacokinetics of
cyclophosphamide on hemodialysis and compared clinical parameters including time
to engraftment and toxicity with parameters of a patient with normal renal
function who also received an unrelated marrow as treatment for CML in first
chronic phase. Our results suggest that TBI/CY is a suitable conditioning regimen
for allogeneic transplantation in patients with hematological malignancy and
renal failure on hemodialysis.
PMID- 9758351
TI - Relapsed chronic myeloid leukemia in accelerated phase 10 years after allogeneic
bone marrow transplantation: full chimera reconversion with donor peripheral
blood stem cells infusion.
AB - We report the case of a 44-year-old male who relapsed in accelerated phase
chronic myeloid leukemia 10 years after a successful bone marrow transplantation
from his HLA-identical brother, and 3 years after 12 months treatment with
interferon-alpha (IFN-alpha) for chronic active hepatitis C (CAH). The patient
was infused with G-CSF-primed peripheral blood cells (PBSC) from the original
bone marrow donor and a full donor reconstitution, with no detectable molecular
disease, was obtained within 4 months without clinical aplasia or GVHD, nor help
from other forms of chemotherapy or use of biological response modifiers. We
speculate that IFN-alpha for CAH delayed the onset of a clinical recurrence of
chronic myeloid leukemia and that in advanced disease PBSCs can provide an
advantageous alternative to donor lymphocyte infusion (DLI).
PMID- 9758352
TI - Autologous reconstitution with BCR-ABL-negative haematopoiesis after T cell
depleted allogeneic BMT for CML.
AB - We report a patient with Ph chromosome-positive CML who underwent an HLA
identical T cell-depleted BMT from a sibling donor. DNA polymorphism analysis
showed complete donor chimaerism after BMT, followed by mixed chimaerism of
granulocytes, natural killer cells and B lymphocytes, with T lymphocytes host
derived at day +120 post BMT. From month +20 haematopoiesis was exclusively of
host origin in all cell lineages. RT-PCR was used in order to detect residual
disease, but at the time, analysis did not show BCR-ABL transcripts. This case is
unusual in that non-malignant stem cells of recipient origin survived the
transplant and reconstituted haematopoiesis after BMT. Two years post transplant,
no molecular or haematological relapse was documented. The observation that
subsequent recipient recovery without molecular relapse implies that, at least in
this case, the GVL effect can occur in the absence of donor T cells.
PMID- 9758353
TI - Matched unrelated allogeneic bone marrow transplantation for recurrent malignant
lymphoma in a patient with X-linked lymphoproliferative disease (XLP).
AB - A 14-year-old male and a maternally related cousin were diagnosed with X-linked
lymphoproliferative disease (XLP) after developing recurrent B-NHL, characterized
by long disease-free intervals and absence of an increased chemoresistance of the
recurrent lymphomas. The demonstration of different clonal IgH gene
rearrangements in two of the lymphomas from one of the patients further supports
that the lymphomas were clonally unrelated. The cousin underwent matched related
BMT, whereas the proband received a deliberately delayed MUD BMT in third CR.
Both are in CR 68 months and 21 months, respectively, post-BMT. Delaying BMT
probably contributes to reducing treatment-related morbidity. We suggest MUD BMT
as a feasible curative strategy for XLP patients with B-NHL lacking matched
related donors.
PMID- 9758354
TI - CD34+-enriched donor lymphocyte infusions in a case of pure red cell aplasia and
late graft failure after major ABO-incompatible bone marrow transplantation.
AB - A variety of immunohematological complications may occur after ABO-incompatible
BMT. We report a CML patient (blood group O) who received a BMT from an HLA
identical sibling (blood group AB). The transplant was followed by normal myeloid
and megakaryocytic engraftment, but erythroblastopenia persisted for more than
200 days after BMT. By bone marrow culture studies, a complement-dependent serum
inhibitor of hemopoiesis was detected, suggesting immunological inhibition of
erythropoiesis. The patient was resistant to a number of treatments such as
intravenous gamma-globulins, prednisolone and high-dose erythropoietin. Full
engraftment with normal blood counts and marrow cellularity was achieved after
two dose-escalating CD34+-enriched donor lymphocyte infusions (DLI). This
experience suggests that CD34+-enriched DLI may be an effective treatment for
patients with delayed engraftment or late graft failure due to major ABO
incompatibility.
PMID- 9758355
TI - Donor lymphocyte infusion at unstable mixed chimerism in an allogeneic BMT
recipient for chronic granulomatous disease.
AB - We report a 14-year-old boy who had successfully received allogeneic BMT for
chronic granulomatous disease and 3 years later was treated with donor lymphocyte
infusion (DLI, 3.3 x 10(8) cells/kg) at unstable mixed chimerism in association
with reduced neutrophil function. Following DLI, the patient developed transient
acute hepatic GVHD, which was confirmed by liver biopsy and was manageable with
cyclosporin A and prednisolone. The patient eventually attained complete
chimerism with improved neutrophil function. At the time of writing (2.5 years
from the DLI), the patient is doing well, free from infectious episodes and
chronic GVHD. Our experience suggests that DLI could be a safe and effective
strategy for dissolution of unstable mixed chimerism in BMT recipients for
inherited disorders.
PMID- 9758356
TI - PBPC as an alternative cell therapy for post-transplant relapse in CML.
PMID- 9758357
TI - How should corticosteroids be used in the treatment of acute GVHD? EBMT Chronic
Leukemia Working Party. European Group for Blood and Marrow Transplantation.
PMID- 9758358
TI - Inoculation of a portion of marrow for transplant as a way to accelerate marrow
recovery.
PMID- 9758359
TI - Expression of beta-catenin, alpha-catenin, and E-cadherin in Barrett's esophagus
and esophageal adenocarcinomas.
AB - Loss of expression and function of the E-cadherin/catenin membrane complex can
result in loss of cell adhesion and contribute to invasive or metastatic
potential in carcinomas. The aim of this study was to examine the expression of
alpha- and beta-catenin and E-cadherin in Barrett's esophagus with and without
dysplasia and in esophageal adenocarcinomas and to identify any relationship with
tumor growth pattern and clinical outcome. Immunoperoxidase staining for alpha-
and beta-catenin and E-cadherin was performed on specimens of Barrett's esophagus
with and without dysplasia and on 54 esophageal adenocarcinoma specimens.
Membranous staining for all of the components was seen in normal gastric and
esophageal mucosa. Abnormal expression of beta-catenin, alpha-catenin, and E
cadherin was significantly associated with higher degrees of dysplasia in
Barrett's esophagus. Fourteen of 16 cases of high grade dysplasia and 7 of 7
cases of intramucosal carcinoma showed abnormal expression of beta-catenin,
compared with 3 of 6 cases indefinite for dysplasia and 11 of 17 cases with low
grade dysplasia (P = 0.022). Similar results were seen for expression of alpha
catenin (P < .01) and E-cadherin (P = .049). In esophageal adenocarcinomas,
preserved expression of these proteins occurred more frequently in well
differentiated tumors; abnormal expression was more common in diffusely
infiltrative poorly differentiated tumors that did not form glands. Focal nuclear
staining for beta-catenin was present in two high-grade dysplasias, two
intramucosal carcinomas, and five adenocarcinomas. No survival advantage was
demonstrated for patients whose tumors retained expression of these cell adhesion
components. In conclusion, abnormal expression of the E-cadherin/catenin membrane
complex is common in esophageal adenocarcinoma and occurs early in the
dysplasia/carcinoma sequence in Barrett's esophagus, indicating that disturbances
in this cell adhesion complex might be important in tumorigenesis and tumor
progression in this disorder.
PMID- 9758360
TI - Pleomorphic lobular carcinoma of the breast: clinicopathologic features of 12
cases.
AB - Pleomorphic lobular carcinoma (PLC) of the breast was recently identified as a
histologic variant of infiltrating lobular carcinoma (ILC) with a poor prognosis.
Twelve cases identified from a large series of breast carcinomas were studied
retrospectively. Of 11 cases with adequate follow up, 9 were fatal. This was
significantly worse than either infiltrating ductal carcinoma (IDC) or classical
ILC (P < or = .002), even when stratified by axillary lymph node status. Among
the fatal cases, the median survival time was 2.1 years, significantly shorter
than that for classical lobular, but not ductal, carcinoma A distinctive pattern
of in situ carcinoma, which has been described as PLC in situ, was identified in
7 of the 12 patients. This in situ component was composed of tumor cells with
nuclear atypia, cytologically similar to the invasive tumor. Most PLCs lacked
estrogen and progesterone receptors and stained with BRST-2, an antibody to gross
cystic disease fluid protein-15, suggesting the presence of apocrine
differentiation. In summary, PLC has many of the histologic features of ILC but
has anaplastic nuclei, abundant cytoplasm, and apocrine differentiation. PLC is
often aneuploid, usually lacks steroid receptors, and has a significantly poorer
prognosis than does classical ILC.
PMID- 9758361
TI - p53 and c-erbB-2 as markers of resistance to adjuvant chemotherapy in breast
cancer.
AB - Recent literature suggests that c-erbB-2 and p53 alteration might be linked to
drug resistance. This study investigates the relation of c-erbB-2 oncoprotein
overexpression and p53 protein accumulation with prognosis in patients with node
positive breast cancer (NPBC) and assesses the modifying effect of these markers
on response to short (1-10 courses) or prolonged (> 10 courses) adjuvant
chemotherapy. This study is based on 458 patients with NPBC diagnosed from 1980
to 1986, with an average of 10 years of follow-up. Marker expression was
evaluated by immunohistochemical analysis on formalin-fixed, paraffin-embedded
material with antibodies to c-erbB-2 and p53. c-erbB-2 was expressed in 17.2% of
the cases, and 19.1% of the tumors stained positively for p53. By multivariate
analysis, women with prolonged adjuvant chemotherapy had better survival than
those with a short course of chemotherapy among patients whose tumor lacked c
erbB-2 oncoprotein expression (P = .0245) or p53 protein accumulation (P =
.0477). Prolonged chemotherapy, however, was associated with little or no change
in survival among patients whose tumor expressed those markers. The present study
adds support to the hypothesis linking c-erbB-2 and p53 expression to drug
resistance.
PMID- 9758362
TI - Laparoscopic biopsy for suspected abdominal lymphoma.
AB - This study retrospectively reviewed the findings in laparoscopic biopsy specimens
from 51 consecutive patients with suspected abdominal lymphoproliferative
disorders. Histologic evaluation was supplemented (as necessary) by paraffin
section or frozen-section immunohistochemical analysis or by Southern blot
hybridization. The laparoscopic procedure was diagnostic of a lymphoproliferative
disorder in 24 patients (47%), of other neoplasms in 5 patients (10%), and of
reactive tissue in 11 patients (22%); no tissue could be obtained for technical
reasons (adhesions and inaccessible lesions) in 11 patients (22%). The 24
patients with lymphoproliferative disorders diagnosed by laparoscopic techniques
included 14 patients with a new diagnosis of lymphoma and 10 patients with
recurrent disease; pathologic findings were diagnostic of diffuse large cell
lymphoma (11 patients), follicular lymphoma (11 patients), chronic lymphocytic
leukemia (1 patient), and lymphocyte-predominant Hodgkin's disease (1 patient).
Previous abdominal cytologic or core-needle biopsy specimens from 11 lymphoma
patients did not yield an unequivocal diagnosis or subtype of lymphoma. The 11
patients (22%) in whom laparoscopic techniques did not produce a tissue sample
needed laparotomy (10 patients) or femoral lymph node biopsy (1 patient) to
document the diagnosis of large cell lymphoma (2 patients), follicular lymphoma
(5 patients), composite lymphoma (1 patient), myeloma (1 patient), neurofibroma
(1 patient), and reactive lymph nodes (1 patient). In the majority of patients
with suspected abdominal lymphoma, laparoscopic techniques provide sufficient
tissue for the diagnosis and classification of lymphoma and for the diagnosis of
other causes of abdominal lymphadenopathy.
PMID- 9758363
TI - Performance of liquid-based, thin-layer cervical cytology: correlation with
reference diagnoses and human papillomavirus testing.
AB - The performance of thin-layer cervical cytology with the use of ThinPrep (Cytyc
Corporation, Boxborough, MA) was assessed by comparing the original independent
diagnosis of ThinPrep slides and conventional smears prepared from 1780 split
samples with the most abnormal diagnosis per patient on the basis of an
independent pathologist's masked review and with the detection of cancer
associated types of human papillomavirus (HPV) DNA. Cases were selected on the
basis of the original diagnoses to include all discordant pairs (those diagnosed
as atypical squamous cells of undetermined significance or higher grade, n =
1017), all concordant abnormal pairs (n = 444), and a random 5% of concordant
normal pairs (n = 319). In screening centers, thin-layer cytology detected 135
(70.3%) of 192 women diagnosed as having squamous epithelial lesions or a higher
grade in the independent review, whereas locally read smears detected 91 (47.4%)
of these patients (P < .001). In hospital-based cytology laboratories, thin-layer
cytology detected 308 (86.3%) of 357 women diagnosed with SILs or a higher grade
in the independent review, compared with 283 (79.3%) diagnosed with smears (P =
.011). Cancer-associated types of HPV DNA were detected in a slightly higher
proportion of women with smears diagnosed as SILs than in women with thin-layer
cytology diagnosed as SILs, whereas the overall number of HPV-associated SILs
diagnosed was higher with thin-layer cytology. These data suggest that the
ThinPrep method detects a higher percentage of SILs as defined in a masked,
independent review than do concurrently prepared smears and that diagnoses of
SILs rendered with ThinPrep correlate with the detection of cancer-associated
types of HPV.
PMID- 9758364
TI - Clinicopathologic comparison of vulvar and extragenital lichen sclerosus:
histologic variants, evolving lesions, and etiology of 141 cases.
AB - Lichen sclerosus (LS) is a persistent inflammatory dermatosis of unknown etiology
with a predilection for the vulva, where it is a risk factor for carcinoma. We
performed a clinicopathologic study on 121 cases of vulvar LS and 20 of
extragenital LS, and we reviewed 49 vulvectomy specimens with LS to define
morphologic findings, identify the earliest lesions, and correlate outcomes with
histologic findings. The vulvar LS lesions were pruritic/burning, white/red, ill
defined patches predominately affecting the labia, perineum, introitus, and
perianal region. The extragenital LS lesions were asymptomatic, pink to ivory
white, coalescing macules or patches with well-defined borders. All of the LS
cases showed dermal sclerosis, vacuolar interface changes, and a lymphocytic
infiltrate underlying the sclerosis, but vulvar LS showed changes of lichen
simplex chronicus or spongiotic dermatitis, dermal eosinophils, and a frequent
absence of atrophy. The presence of eosinophilic spongiosis, marked lymphocyte
exocytosis, dermal eosinophils, and excoriations predicted poor symptomatic
response to treatment. Patch testing is recommended for these individuals as
these findings suggest an allergic contact dermatitis. Examination of vulvectomy
specimens revealed either a lichenoid interface or a spongiotic dermatitis in
continuity with pathognomonic LS. Additionally, in these contiguous regions, we
identified histologic changes that might represent evolving lesions of LS,
suggesting a multifactorial etiology. In conclusion, vulvar LS was significantly
different clinicopathologically from extragenital LS, and if only classic
features of LS were used for pathologic diagnosis, many cases of vulvar LS would
be missed. Therefore, we proposed as the minimal histologic criterion for LS the
presence of a vacuolar interface reaction pattern in conjunction with dermal
sclerosis (homogenized and hyalinized eosinophilic collagen bundles) of any
thickness intervening between the inflammatory infiltrate and epithelium and or
vessel walls.
PMID- 9758366
TI - Frequency of bcl-2 expression in non-Hodgkin's lymphoma: a study of 778 cases
with comparison of marginal zone lymphoma and monocytoid B-cell hyperplasia.
AB - The oncoprotein, bcl-2, is expressed in various types of non-Hodgkin's lymphoma
(NHL). Immunodetection of this protein is a useful method for distinguishing
follicular hyperplasia from follicular lymphoma. Although bcl-2 might also be a
useful marker for distinguishing reactive monocytoid B-cell hyperplasia from its
putative malignant counterpart, marginal zone lymphoma, there were no extensive
studies to date that tested this. Therefore, we performed a survey of bcl-2
expression in 778 cases of NHL using immunohistochemical techniques applied to
routinely processed and paraffin-embedded tissues. Of 20 reactive monocytoid B
cell hyperplasias, none were bcl-2 positive, compared with 118 (79%) of 150
marginal zone lymphomas (P = .001). With respect to the follicular lymphomas in
our study, of the 110 Grade I lymphomas, 107 (97%) were bcl-2 positive, 119 (83%)
of the 143 Grade II lymphomas were positive, and 71 (74%) of the 96 Grade III
lymphomas were positive. The bcl-2 positivity of Burkitt-like high-grade B-cell
lymphoma was significantly different from that of Burkitt's lymphoma (4 [67%] of
6 vs. 0 of 5; P = .02). T-cell NHL had a significantly lower bcl-2 positivity
than did B-cell NHL (10 [45%] of 22 vs. 627 [83%] of 756; P = .0001). Therefore,
bcl-2 is a highly sensitive marker for follicular lymphoma and a useful marker
for distinguishing reactive monocytoid B-cell hyperplasia from marginal zone
lymphoma The significant difference in bcl-2 positivity between Burkitt-like high
grade B-cell lymphoma and Burkitt's lymphoma suggests an additional diagnostic
use for this protein.
PMID- 9758367
TI - Prognostic factors in gastric cancer.
AB - Molecular assays related to cell proliferation correlate with stage and/or
survival in a variety of tumors. We immunostained formalin-fixed, paraffin
embedded tissue sections from 61 patients with gastric adenocarcinoma (21 biopsy
and 40 gastrectomy specimens) for cyclin A, cyclin B1, p34cdc2, p120, MIB1, and
proliferating cell nuclear antigen (PCNA) by automated methods. HER-2/neu gene
amplification was analyzed by automated fluorescence in situ hybridization
(FISH). Immununostains, FISH results, and pathologic stage were compared with
length of survival. Forty-three percent of the cases showed amplification of HER
2/neu. Sixty-two percent of cases showed positive immunostaining for cyclin A,
38% for cyclin B1, 31% for p34cdc2, 49% for p120, 69% for MIB1, and 33% for PCNA.
On univariate analysis, pathologic stage (P = .003) and HER-2/neu gene
amplification (P < .001) correlated with length of survival. Cyclin A, cyclin B1,
p34cdc2, p120, MIB1, and PCNA did not correlate with survival. On multivariate
analysis, pathologic stage (P = .015) and HER-2/neu gene amplification (P = .002)
independently predicted survival. These correlations were unrelated to tubular or
signet ring cell histologic characteristics or to location within the cardia or
more distally. Pathologic stage and HER-2/neu gene amplification by FISH were
independent prognostic factors in gastric cancer, but the various proliferation
markers that we studied did not correlate with survival.
PMID- 9758365
TI - Seprase, a membrane-bound protease, is overexpressed by invasive ductal carcinoma
cells of human breast cancers.
AB - The increased cell surface expression of the serine integral membrane protease,
seprase, has been associated with the invasive behavior of human melanoma cell
lines in vitro. The present study investigates the expression of seprase in
malignant, premalignant, benign, and normal human breast tissues. The 170-kDa
gelatinase activity of seprase was identified in extracts of infiltrating ductal
carcinomas (IDC). Protein bands corresponding to the proteolytically active 170
kDa seprase dimer and its 97-kDa seprase subunit protein were identified by
immunoblot analysis of IDC extracts using an antiserum elicited against
immunoaffinity-purified seprase. Immunohistochemical analysis of seprase
expression in 41 formalin-fixed and paraffin-embedded specimens of human breast
tissue revealed preferential immunoreactivity with the malignant cells of IDC (27
cases). Within individual IDC specimens, the stromal cells or morphologically
normal epithelium revealed low labeling that was always significantly less than
the labeling of neoplastic cells. Lymph node metastases of IDC cells were also
strongly positive, but the lymphoid tissue in affected nodes was not stained.
Neoplastic cells in DC in situ (5 cases) exhibited variable levels of staining.
Epithelial cells of benign fibroadenoma specimens (2 cases) and benign
proliferative breast disease (5 cases) exhibited little or no immunoreactivity.
Epithelial cells of normal breast tissue (1 case) were not stained. The
overexpression of seprase by DC cells is consistent with seprase having a role in
facilitating invasion and metastasis of IDC of the breast. The cell surface
localization of seprase could be used to target therapeutic agents to malignant
breast cells.
PMID- 9758368
TI - Expression of MMP-1, TIMP-1, and type I collagen in laryngeal carcinoma.
AB - Matrix metalloproteinases (MMPs) are thought to play an important role in tumor
invasion and metastasis. To our knowledge, however, no previous report examined
the histologic localization of matrix metalloproteinase-1 (MMP-1), tissue
inhibitor of metalloproteinase-1 (TIMP-1) and Type I collagen in laryngeal
carcinoma from the same samples. In this study, immunohistochemical staining for
MMP-1, TIMP-1, and Type I collagen was performed on paraffin-embedded sections
from 83 laryngeal squamous cell carcinomas. Twenty of the 83 tumors were examined
for MMP-1 and TIMP-1 mRNA using in situ hybridization (ISH). Immunohistochemical
and ISH analyses indicated that squamous cancer cells as well as stromal cells
such as fibroblasts, macrophages, and mononuclear and endothelial cells expressed
MMP-1 and TIMP-1 in the area adjacent to the tumor. The localization of MMP-1 and
TIMP-1 protein is similar to that of their respective transcripts. Dense or
moderate patterns of Type I collagen were associated with a tendency toward
positivity for TIMP-1 and negativity for MMP-1 (P < .002). A sparse pattern of
Type I collagen was associated with a tendency toward positivity for MMP-1 and
negativity for TIMP-1 (P < .004). The patterns of Type I collagen staining
correlated significantly with imbalances in MMP-1 and TIMP-1 expression (P <
.001). Matrix degradation and remodeling in squamous cell carcinoma of the larynx
might be attributable to an imbalance in the expression of MMP-1 and TIMP-1.
PMID- 9758369
TI - Overexpression of the ERK/MAP kinases in oral squamous cell carcinoma.
AB - Mitogen-activated protein kinase (MAPK) is a serine-threonine kinase that is
activated by various extracellular stimuli. Extracellular signal-regulated
kinases (ERK1 and ERK2), an MAPK subfamily, are activated by many oncogenes, such
as ras and raf, and they induce cell proliferation. myc is also an oncogene and
one of the targets of ERKs. Mutations of ras and overexpression of myc were found
in various human cancers, and ERKs were also reported to play a role in
carcinogenesis. In this study, we examined 39 biopsy specimens of oral squamous
cell carcinoma (OSCC) and 5 of normal gingival mucosa for the expression of ERK
protein and the proliferation marker, MIB-1 (Ki-67 antibody). Thirteen OSCC
specimens and five normal gingival biopsies were also examined for the expression
of ERKs mRNA by in situ hybridization. Double staining for ERKs and MIB-1 was
also performed. Histologically, 18 patients (46%) were diagnosed with well
differentiated SCC, 17 (44%) with moderately differentiated SCC, and 4 (10%) with
poorly differentiated SCC. The histologic grade correlated with the MIB-1 index.
The localization of ERK1 was similar to that of ERK2. Positive signals for ERK
proteins were localized in superficial keratinocytes in normal gingival mucosa,
whereas these mRNAs were weakly positive in the basal and spinous layer. Basal
and suprabasal cells were positive for MIB-1. In well-differentiated and
moderately differentiated OSCC, positive signals for ERK mRNA and proteins were
found at higher levels than in normal gingival mucosa in keratotic cells around
cancer pearls. Some cells showed positive signals for ERKs and MIB-1.
Furthermore, most cancer cells in poorly differentiated SCC were positive for
both ERK and MIB-1. The histologic grade was statistically related to the
percentage of cells positive for both ERK and MIB-1. This suggested that ERKs
might be related to proliferation in OSCC.
PMID- 9758370
TI - Expression of bcl-2, p53, and p21 in benign and malignant prostatic tissue before
and after radiation therapy.
AB - Abnormalities in genes of the apoptotic pathway might contribute to survival in
prostatic cancer (PCa) cells after radiation therapy (RT). We investigated the
immunohistochemical expression of the products of the p53, p21WAF1, and bcl-2
genes in pre-RT and post-RT biopsy specimens from 38 patients with locally
advanced PCa. All of the 38 patients underwent a uniform protocol of RT with or
without neoadjuvant hormonal therapy. Immunohistochemical staining for expression
of the products of the p53, p21WAF1, and bcl-2 genes was performed on material
from pre-RT and post-RT specimens. Sufficient tissue for analysis was available
from 25 of the pre-RT and 38 of the post-RT biopsy specimens. In benign prostatic
epithelium, RT resulted in expression of p53 (2 [8%] of 25 pre-RT specimens vs.
15 [71%] of 21 post-RT specimens; P < .001) and increased expression of bcl-2 (1
[5%] of 18 pre-RT vs. 18 [86%] of 21 post-RT; P < .001). There was no change in
the expression of p21WAF1 (1 [4.5%] of 22 pre-RT vs. 4 [17%] of 23 post-RT; P =
NS). Post-RT specimens were positive for PCa in 24 (63%) of 38 cases. In the PCa
tissue, p53 expression was seen in 10 (42%) of 24 pre-RT and 12 (63%) of 19 post
RT samples (P = NS). A significant upregulation of p53 was seen in the subgroup
of patients who did not receive neoadjuvant hormonal therapy (9 [82%] of 11 vs. 3
[38%] of 8; P = .05). No significant change in p21WAF1 (5 [21%] of 24 vs. 5 [33%]
of 15; P = NS), or bcl-2 (4 [18%] of 22 vs. 3 [21%] of 14; P = NS) expression was
detected. There was no significant correlation between immunohistochemical
expression of apoptosis-related markers and treatment failure. We concluded that
RT induced upregulation of the bcl-2 and p53 gene products in benign prostatic
tissue and that this likely reflected a protective mechanism in genetically
unaltered epithelium. Increased p53 expression in PCa was only seen in patients
without neoadjuvant hormonal treatment, indicating that the cancer cells with
abnormal p53 were at least partially protected from RT-induced cell death.
PMID- 9758371
TI - Sarcoid, amyloid, and acute myocardial failure.
AB - We report the case of a 58-year-old woman, with an 8-year history of pulmonary
sarcoidosis, who died in acute myocardial failure after cardiac catheterization.
Systemic amyloid, likely of the AL type, was found to involve her myocardial
interstitium and intramyocardial coronary arteries, as well as her spleen,
thyroid, kidneys, and bone marrow. Her acute myocardial failure was thought to be
the result of focal myocardial infarcts secondary to amyloid vasculopathy and of
superimposed chronic restrictive myocardial function caused by amyloid. Five
previously reported cases of concurrent sarcoidosis and AA-type amyloid remind us
that there is significant experimental data implicating the inflammatory process
of sarcoidosis in the causation of AA-type amyloidosis. The concurrence of
sarcoidosis and AL-type systemic amyloid seen in this patient was reported in the
literature once before, and we think the concurrence was a coincidence.
PMID- 9758372
TI - Splenic marginal zone cell lymphoma associated with clonal B-cell populations
showing different immunoglobulin heavy chain sequences.
AB - Splenic marginal zone cell lymphomas (SMZCLs) are low-grade B-cell lymphomas that
usually present with massive splenomegaly and subtle (subleukemic) peripheral
blood involvement. Polymerase chain reaction (PCR) analysis of peripheral blood
from a patient with subleukemic SMZCL showed evidence of two clonal
immunoglobulin heavy chain (IgH) gene rearrangements. IgH PCR analysis of DNA
derived from the patient's splenic neoplasm demonstrated a single clonal IgH
rearrangement, which had a different electrophoretic mobility from either of the
two PCR products detected in the patient's peripheral blood. Additional
characterization of these PCR products by DNA sequencing demonstrated two
independent IgH rearrangements in the peripheral blood, one of which used IgH
joining region 6c (JH6C) and the other JH4. A different IgH rearrangement was
present in the splenic tumor, which used JH4a. No sequences from the splenic
neoplasm were detected in the peripheral blood and vice versa. This case
illustrates that PCR might reveal monoclonal populations in peripheral blood
unrelated to the presence of lymphoma in other anatomic compartments.
PMID- 9758374
TI - An easy and quick stain for the demonstration of Helicobacter pylori.
PMID- 9758375
TI - Regional left ventricular wall motion abnormalities in myocardial infarction and
mitral annular descent velocities studied with pulsed tissue Doppler imaging.
AB - We evaluated global left ventricular (LV) systolic function from mitral annular
systolic motion velocities measured by pulsed tissue Doppler imaging in patients
with previous myocardial infarction (MI) and LV regional wall motion
abnormalities. The subject group consisted of 45 patients with wall asynergies, 3
with ischemic cardiomyopathy, 8 with dilated cardiomyopathy, and 15 healthy
control subjects. The peak systolic descent velocity (Sw) and the time from the
electrocardiographic Q wave to the peak of the systolic wave (Q-Sw) were measured
at 6 mitral annular sites obtained from 2-dimensional apical long-axis, 4
chamber, and 2-chamber echocardiograms; these variables were compared with the LV
ejection fraction (EF) calculated from the left ventriculogram. The mean Sw at
the sites corresponding to the infarct regions was significantly lower and the
mean Q-Sw was significantly longer in the MI groups than in the control group.
The mean Sw and Q-Sw at all 6 sites in the ischemic and dilated cardiomyopathy
groups were significantly lower and longer, respectively, than those of the
control group. There were significant correlations between the EF and the means
of the Sw and Q-Sw values at the sites corresponding to the infarct regions in
the MI groups. In the ischemic and dilated cardiomyopathy groups, significant
correlations existed between the EF and the means of the Sw and Q-Sw values at
all 6 sites. Thus the parameters obtained from mitral annular systolic motion
velocities with pulsed tissue Doppler imaging reflect LV asynergy corresponding
to the infarct regions in patients with MI, and global LV systolic function may
be evaluated with these parameters.
PMID- 9758377
TI - Left ventricular contraction pattern changes with age in normal adults.
AB - Left ventricular ejection fraction is known to be unchanged or slightly increased
with advancing age. This echocardiographic study, including 40 healthy subjects
18 to 70 years old, shows that this is a net effect of decreased contractions in
the long axis and increased in the short axis. From age 18 to 70 years, the
longitudinal shortening decreases by 20% (P < .001) and the short-axis diameter
shortening increases by 18% (P=.012). Multiple regression analysis showed strong
correlation to age for both short- and long-axis contractions and no significant
additional explicatory power when the variables systolic blood pressure, left
ventricular wall thickness, heart rate, or sex were included. There was no
significant correlation between diameter changes during the isovolumic phases and
age. The findings have practical implications when calculating ejection fraction
from M-mode measurements. Teichholz's formula will overestimate ejection fraction
in elderly subjects, and calculation of ejection fraction from mitral ring motion
will overestimate it in young subjects.
PMID- 9758376
TI - Nongeometric quantitative assessment of right and left ventricular function:
myocardial performance index in normal children and patients with Ebstein
anomaly.
AB - Assessment of ventricular systolic function has been based on the geometric
models of ventricular shape. This study was designed to define normal values for
a nongeometric myocardial performance index (MPI) in children and to evaluate the
utility of MPI in congenital heart disease. The MPI measures the ratio of total
time spent in isovolumic activity (isovolumic contraction time and isovolumic
relaxation time) to the ejection time. The right ventricular (RV) and left
ventricular (LV) MPI were measured in 152 normal children (ages 3 to 18 years)
and 45 preoperative patients with Ebstein anomaly (age 1 week to 52 years). In
normal children, the RV MPI was 0.32+/-0.03 and the LV MPI was 0.35+/-0.03. In
the Ebstein group, both RV and LV MPI were abnormally increased compared with age
matched normal subjects (Ebstein group: RV MPI=0.49+/-0.12, LV MPI=0.42+/-0.09, P
< .001). Increasing RV dysfunction was associated with progressively increasing
(abnormal) values of RV MPI (P < .001). The myocardial performance index
quantitatively reflects ventricular performance in patients with complex
ventricular geometry (ie, Ebstein anomaly). In the absence of a geometric
solution, this nongeometric index is particularly appealing for the assessment of
RV or LV performance.
PMID- 9758378
TI - Right ventricular volumes revisited: a simple model and simple formula for
echocardiographic determination.
AB - Our objective was to establish a crescentic model of the right ventricle as the
basis of a reported 2/3 (Area)(Length) empirical formula for volume. This formula
has been investigated by others without cognizance of its connection to a clear
geometric model. The particular model, an ellipsoidal shell or difference of
ellipsoids, has been investigated by several groups by using different volume
formulas. Accordingly, we obtained echocardiographic images in 2 orthogonal
planes from 7 patients and 4 volunteers. Specified area and length measurements
from these images were used to calculate right ventricular volumes. These volumes
were compared with values determined through multislice, magnetic resonance
imaging with summation of lumen areas, a widely accepted standard. Obtained high
correlations compared favorably with those of previous investigators who used
equivalent but less well understood methods. We conclude that the ellipsoidal
shell model of the right ventricle provides a simple area-length formula for the
determination of lumen volume with echocardiography.
PMID- 9758380
TI - Comparison of transesophageal Doppler methods with angiography for evaluation of
the severity of mitral regurgitation.
AB - Doppler evaluation of mitral regurgitation remains difficult; thus, a head-to
head comparison of the diagnostic accuracy of Doppler methods was undertaken.
Fifty patients with native mitral regurgitation underwent multiplane
transesophageal echocardiography within 5 days of catheterization. Angiographic
grade of mitral regurgitation and, in 20 patients with grade II-IV regurgitation,
invasively determined regurgitant stroke volume were compared with color Doppler
area, regurgitant jet diameter, ratio of systolic to diastolic peak pulmonary
venous flow velocities, and (based on the proximal convergence zone) maximal
regurgitant flow rate and regurgitant orifice area. Rank correlation coefficients
of angiographic grade with Doppler parameters were 0.61 for color jet area, -0.61
for pulmonary venous flow velocity ratio, 0.69 for color jet diameter, 0.79 for
maximal regurgitant flow rate, and 0.78 for regurgitant orifice area (all P <
.01). Convergence zone-based parameters also correlated best (r=0.73) with
invasively determined regurgitant stroke volume. Receiver operating
characteristic curve analysis confirmed higher diagnostic accuracy for proximal
jet width and proximal convergence zone parameters than for color jet area or
pulmonary venous flow velocity ratio. Proximal convergence zone parameters and
proximal color jet diameter best distinguished severe from mild forms of mitral
regurgitation.
PMID- 9758379
TI - Quantification of aortic regurgitant volume by a newly developed automated
cardiac flow measurement method: an in vitro study.
AB - BACKGROUND: Quantifying regurgitant volumes is important for treatment of
patients with valvular aortic regurgitation. Simple, reliable methods to quantify
aortic regurgitation have been sought both in the catheterization laboratory and
the echocardiography laboratory. OBJECTIVES: The aim of our study was to
investigate the applicability of a new automated cardiac flow measurement method
with color Doppler velocity data for quantifying retrograde flow volumes of
aortic regurgitation in an ascending aorta model. METHODS AND RESULTS: A 2
chamber pulsatile flow system with a modeled ascending aorta and a regurgitant
aortic valve orifice was developed. The model could generate "aortic
regurgitation-like" waveforms through the use of an electrically controlled
valve. The regurgitant flows through the orifice (8.5 to 28.1 mL/beat) were
measured by an ultrasound flowmeter; they were also calculated in the ascending
aorta 1.0 cm above the orifice by the automated cardiac flow measurement method,
which integrated spatially distributed digital flow velocity data through
"diastole." Calculated regurgitant volumes measured with the low color Doppler
filter (5.4 cm/s) agreed well with those measured with the flowmeter (r=.99, P <
.001, mean difference=2.2+/-3.7 mL). However, the regurgitant volume was
underestimated when 2 higher filter settings were used (9.6 and 10.9 cm/s).
Although there was no significant difference in mean volume, higher frame rate
(19 frames/s) provided more reproducible results with smaller standard deviation
as compared with lower frame rate (7 frames/s). CONCLUSIONS: This new automated
cardiac flow measurement method appears to be promising for semiautomatic
quantification of aortic regurgitant volume. Appropriate choice of filter setting
and high frame rate assists reliable data acquisition.
PMID- 9758381
TI - Transthoracic echocardiographic measurement of coronary artery diameter:
validation against quantitative coronary angiography.
AB - There has been no in vivo validation of the use of transthoracic echocardiography
to measure distal left anterior descending coronary artery (LAD) diameter. We
therefore undertook transthoracic echocardiography on 65 male patients
immediately before cardiac catheterization to compare echocardiographic and
angiographic findings. The distal LAD was successfully imaged in 41 (63%)
patients; 29 of these had an angiographically normal distal LAD as assessed by an
independent cardiologist and formed the study group. Transthoracic
echocardiographic and quantitative coronary angiographic measurements of distal
LAD diameter were made. Echocardiographic measurements ranged from 0.14 to 0.28
cm (mean 0.20 cm). Angiographic results ranged from 0.12 to 0.28 cm (mean 0.195
cm). Correlation between techniques was good (r=.925). The maximum discrepancy
between transthoracic echocardiography and quantitative coronary angiography was
0.03 cm. Limits of agreement were +0.032 to -0.024 cm. We conclude that
transthoracic echocardiography is a valid technique for measurement of distal LAD
diameter.
PMID- 9758382
TI - Survey of hospital-based echocardiography services.
AB - A survey of policies and procedures for delivering echocardiography services in
acute-care hospitals in the state of Illinois was performed to define the present
state of the art. Indications for ordering an echocardiographic study were
relatively uniform, as the normalized, annual number of transthoracic
echocardiograms performed were similar throughout the state. Training criteria
for becoming an echocardiography physician-interpreter, although published by
national societies, were variable. Sonographer training was predominantly
provided through an informal apprenticeship system, and both physician and
sonographer continuing medical education requirements were minimal.
Echocardiogram reports were primarily generated by free text dictation or
transcription and were transmitted to the ordering physician in a variety of
ways. There was no agreement regarding what diagnosis constituted a "stat value."
National specialty societies such as the American College of Cardiology and the
American Society of Echocardiography should address these issues to assist
physicians and hospitals in improving their echocardiography services.
PMID- 9758383
TI - Severely reduced left atrial appendage function: a cause of embolic stroke in
patients in sinus rhythm?
AB - Recently, attention has been focused on transesophageal echocardiographic
detection of left atrial appendage function to assess of risk of thrombus
formation because of potential benefit of anticoagulation therapy. However, most
of these studies have been conducted in patients with atrial fibrillation or
mitral valve disease. In this article we review cases of 2 patients without
valvular disease who had embolic stroke in sinus rhythm. Transesophageal
echocardiography revealed thrombi in the left atrial appendage in both patients.
The left atrial appendage function in these patients was compared with that in
patients with chronic atrial fibrillation and a control group in sinus rhythm.
Left atrial appendage function in the patients with stroke and sinus rhythm was
significantly lower than that of patients in the control group in sinus rhythm (P
< .001) and was similar to the appendage function in patients with chronic atrial
fibrillation. These observations provide further evidence that the finding of
reduced left atrial appendage function can be a cause of stroke in patients with
sinus rhythm even in the absence of mitral valve disease. Reduced left atrial
appendage function may identify patients with unexplained stroke who should
receive anticoagulation therapy even in the absence of detectable appendage
thrombi.
PMID- 9758384
TI - Prenatal diagnosis of abnormal persistence of the right or left umbilical vein:
report of 4 cases and literature review.
AB - Four cases of prenatally diagnosed abnormal persistence of an umbilical vein are
presented. Of the 4 cases, 2 are in association with congenital heart disease, 2
are in the setting of abdominal visceral situs inversus, and 1 is with
extrahepatic persistence of an umbilical vein. Whereas persistent right umbilical
vein may occur in 0.2% to 0.4% of fetuses undergoing screening prenatal
ultrasonography, reports of an extrahepatic course are rare. A review of the 62
reported cases of prenatally diagnosed abnormally persistent umbilical vein
revealed 9 fetuses (15%) with a congenital cardiovascular malformation, of which
6 were significant enough to likely require surgery. Other organ system
malformations were present in 9 patients (15%). The prevalence of congenital
cardiovascular malformations was 3 (7%) of 42 when combining 2 large series that
were relatively unbiased for referrals for possible heart disease. Detailed
evaluation by ultrasonography and fetal echocardiography should be used for
prenatally diagnosed cases of abnormal persistence of an umbilical vein.
PMID- 9758386
TI - Outcomes research review.
PMID- 9758385
TI - Bifid left atrial appendage with thrombus: source of thromboembolism.
AB - Three patients with embolic events were found on transesophageal echocardiography
(TEE) to have bifid left atrial appendage (LAA). In these patients, large mobile
thrombi were found only in the posterior limb of the appendage. The best views to
demonstrate the posterior limb were between 85 and 155 degrees from the
transverse plane with the use of a multiplane TEE probe. To avoid overlooking
this pathologic condition, we recommend that complete evaluation of the LAA
should include rotation of the TEE transducer up to 155 degrees from the
transverse plane.
PMID- 9758387
TI - Modeling of spreading cortical depression using a realistic head model.
AB - Barkley and colleagues in 1990 reported large amplitude waves (LAWs) in time
series magnetoencephalography (MEG) recordings from migraine patients and
inferred that these LAWs arose from spreading cortical depression (SCD). SCD
propagates slowly across the cortex in all species in which it has been observed.
Previously, we reported that LAWs could be simulated and compared with the
recorded signals using the four-sphere model (Wijesinghe and Tepley 1997). We
showed that LAWs could arise from the propagation of SCD across a sulcus. In this
paper, we model LAWs using a realistically shaped head model based on magnetic
resonance images (MRI) (Roth et al. 1993). Simulated signals using this model are
similar to the recorded signals. In this model, current dipoles represent the
excitable neurons in the cortex and magnetic fields created by these individual
dipoles are calculated. The magnetic field arising from the excited area of
cortex is obtained by summing the fields due to these individual dipoles.
PMID- 9758388
TI - Application of the directed transfer function method to mesial and lateral onset
temporal lobe seizures.
AB - The directed transfer function (DTF) method is a multichannel analysis based on
an autoregressive model that detects flow of seizure activity. This report
extends the application of the DTF method to compare patterns of flow of seizures
with different sites of origin. Analysis of a seizure originating from mesial
temporal structures is compared with a seizure originating from lateral temporal
neocortex; both complex partial seizures were recorded with intracranial
electrodes that combine subdural grid arrays and depth electrodes. The DTF method
has the potential to determine patterns of flow of activity, including periods
when visual analysis of the intracranial ictal EEG may not allow for definitive
source localization. The extension of the DTF analyses into integrated DTF (IDTF)
formats is also illustrated. When activity of a relatively discrete frequency can
be identified, the IDTF analysis facilitates display of patterns of flow of this
selected activity.
PMID- 9758389
TI - Spatial EEG synchronisation over sensorimotor hand areas in brisk and slow self
paced index finger movements.
AB - The changes of spatial EEG synchronisation during brisk and slow voluntary self
paced movements of the right and left index finger were analysed in 12 right
handed and 11 left-handed subjects. EEG was recorded from the left and right
sensorimotor area using 24 closely spaced electrodes. A novel measure of spatial
EEG synchronisation, omega-complexity, was computed separately for the left and
right sensorimotor area in 64 overlapping one-second epochs representing 4.5 s of
the pre-movement and 3.5 s of the post-movement period. Omega-complexity was
higher, hence spatial synchronisation was lower, in slow than in brisk movements,
especially in the right-handed. A sustained increase of omega-complexity was
observed during execution of a slow movement. A decrease of omega-complexity
which was often associated with a brief burst of spatially synchronised 10-Hz
oscillations occurred at the onset of extensor muscle contraction. We suggest
that increased spatial EEG synchronisation at movement onset may prevent
"spillover" of excitation from the sensorimotor hand area to other cortical
regions. During movement, the cortical neuronal assemblies subserve distinct,
specialised functions manifesting in increased omega-complexity.
PMID- 9758390
TI - Left frontal EEG coherence reflects modality independent language processes.
AB - Previous studies showed that distinct components of higher cognitive processes
like memorizing of words could be correlated with changes in different frequency
bands of the human EEG. This study was designed in order to find out if 1) some
frequency bands show power and coherence changes only due to the modality of
presented stimuli (either auditory or visual) and 2) if other frequency bands
show modality independent effects which should reflect real cognitive-linguistic
differences between word classes (either concrete and abstract nouns). EEG was
recorded from sixteen right-handed females which had to memorize auditorily and
visually presented concrete and abstract nouns. Results show the alpha-1 band to
reveal no differences between word classes but demonstrate an influence of
modality of stimulus presentation. The only modality independent differences
between concrete and abstract noun processing were found in the delta, theta and
beta-1 band at left frontal electrodes.
PMID- 9758391
TI - Addressing misallocation of variance in principal components analysis of event
related potentials.
AB - Interpretation of evoked response potentials is complicated by the extensive
superposition of multiple electrical events. The most common approach to
disentangling these features is principal components analysis (PCA). Critics have
demonstrated a number of caveats that complicate interpretation, notably
misallocation of variance and latency jitter. This paper describes some further
caveats to PCA as well as using simulations to evaluate three potential methods
for addressing them: parallel analysis, oblique rotations, and spatial PCA. An
improved simulation model is introduced for examining these issues. It is
concluded that PCA is an essential statistical tool for event-related potential
analysis, but only if applied appropriately.
PMID- 9758392
TI - Functional hemispheric asymmetry assessment in a visual language task using MEG.
AB - We used magnetoencephalography (MEG) to assess the degree of hemispheric
activation in eleven normal, right-handed subjects with no history of
neurological disorder or learning disability during performance of a word- and a
face-recognition tasks. Neuromagnetic activity was recorded using a whole-head
system, and the sources of the recorded magnetic fields were modeled as single
equivalent current dipoles. Early (<200 msec) cerebral activation, defined by the
number of dipoles identified by the data-fitting algorithm, was localized in the
occipital cortex during both tasks, as expected. During the language task, the
extent of the later (>200 msec) cerebral activation was approximately double in
the left hemisphere in almost all subjects, involving temporal and
temporoparietal areas. In contrast, during the face-recognition task, the
corresponding activation was mostly symmetrical across the two occipital lobes,
also involving the posterior-inferior aspect of the right temporal lobe. Our
results suggest that the MEG is a suitable method of assessing noninvasively
hemispheric specialization for language.
PMID- 9758393
TI - The relationship between satisfaction with mouth and number and position of
teeth.
AB - A number of studies have suggested that many people are satisfied with less than
28 natural teeth. This review assesses the evidence. The main conclusion was that
less than a complete dentition can satisfy oral functional needs. Missing
posterior teeth were not very important from a subjective aspect. The demand for
replacement of missing teeth is related to the position of missing teeth. Most
studies agree that individuals were more concerned about missing anterior teeth
and having anterior rather than posterior teeth replaced. Aesthetics is more
important than function for a great majority of individuals. However, certain
socio-demographic factors, such as age, can change the subjective need for
replacement of missing teeth. Some studies have assessed the social and
psychological impacts on oral health status. The position of missing teeth was
assessed, in terms of groups of missing teeth, anterior or posterior, that would
affect an individuals' subjective need for replacement by partial prosthesis.
Large numbers of people that have free end removable partial dentures made do not
wear them because subjective needs are lower than normatively determined needs
for replacement of missing teeth. Some studies have proposed alternatives to the
replacement of missing teeth, such as the shortened dental arch concept.
PMID- 9758394
TI - Relationship between juvenile bruxing and craniomandibular dysfunction.
AB - A longitudinal study was conducted over 5 years to investigate the relationship
between juvenile bruxing and craniomandibular disorders. A total of 150 bruxers
between the ages of 6 and 9 years were examined for oral parafunctions and TMJ
symptoms. Of these, 126 were re-examined for the same signs and symptoms after 5
years. The results showed that only 17 individuals had retained their bruxing
habit. In common with other studies, we found that symptoms reduced with age. It
was concluded that juvenile bruxing was a self-limiting condition which does not
progress to adult bruxism and which appeared to be unrelated to TMJ symptoms.
PMID- 9758395
TI - Comparison of marginal sealing ability of new generation bonding systems.
AB - The purpose of this in vitro study was to evaluate the enamel and dentine
marginal sealing ability of four new generation composite bonding systems. Two
Class V preparations, which were solely in enamel and dentine/cementum, were made
on the buccal surfaces of 96 freshly extracted molar teeth. The teeth were
randomly divided into four groups of 24 and restored with composite resin (Silux
Plus) utilizing the following bonding systems: Scotchbond Multi-purpose (SB),
Fuji Bond LC (FB), Prime & Bond 2.0 (PB) and Bisco One-step (BC). The
restorations were finished immediately after photo-polymerization and stored in
saline at 37 degrees C for 1 week. Half of the specimens in each group were then
thermally stressed for 500 cycles. All restorations were then subjected to dye
penetration testing, sectioned and scored. Results revealed no statistically
significant difference (P < 0.05) in dye penetration scores for the different
bonding systems with the exception of leakage at the dentine margins of thermally
stressed specimens where FB exhibited significantly better sealing ability
compared with the other bonding systems and BC exhibited significantly less
leakage than PB. The marginal seal of 'one-step' (PB and BC) and resin-modified
glass-ionomer (FB) bonding systems appear to be as effective as 'two step'
systems like SB. Thermal stresses had some influence on marginal seal but this
was both product and tissue specific.
PMID- 9758396
TI - CMDME (curved mesh diagram of mandibular excursion) method for visualization and
diagnosis of mandibular movement.
AB - The CMDME (curved mesh diagram of mandibular excursion) method was developed for
easy visualization and diagnosis of mandibular movement. This method uses
measured mandibular movement to produce a diagram of the range, shape, and
inclination of mandibular excursion in three dimensions using any arbitrary
landmark of the mandible. First, the mandibular movement of a subject was
measured by an opto-electronic movement analysis system capable of measuring
mandibular movement with six degrees-of-freedom at a sampling frequency of 100
Hz. For the measurement, the subject was initially instructed to perform four
repetitions of mandibular excursion at will, with tooth contact, each lasting 30
s. A total of 12 000 positions of the mandible were thus obtained. Secondly, an
attempt was made to match these positions to intersection points (0.1 mm apart)
of a CMDME (i.e. mesh) for arbitrary mandibular landmarks with intercuspal
position at the origin. The CMDME method can visualize mandibular excursion, and
can be used to compare several landmarks, different subjects, or different times.
This makes this method an effective diagnostic tool for mandibular movement.
PMID- 9758397
TI - Complications and primary failures related to fixed metal ceramic bridge
prostheses made by dental students.
AB - Porcelain fused to metal provides better aesthetics in fixed partial dentures
than veneers with gold-resin that were used formerly. The aim of our study was to
evaluate complications and primary failures of fixed metal ceramic bridge
prostheses made by dental students. We studied 61 patients (32 women, 29 men,
mean age 49 years, range 28-73 years) treated during years 1990-1993. Data were
collected from the patient files. Altogether 82 bridges were made (mean 4.1
units, range 2-6), 221 abutments (mean 2.7, range 2-6) and 136 pontics (mean 1.6,
range 1-4). Forty-seven cast cores were used in 29 bridges (mean 0.4 cores, range
1-3) and semiprecious attachments as an extra attachment in two bridges. Seven
teeth were extracted due to complication and/or failure during endodontic
treatment and root canal perforation during preparation. In two cases the
abutment tooth was fractured by removing the old crown. Four unsuccessful bridges
were remade and in seven cases the firing of porcelain was renewed. The study
concludes that most common failures of fixed metal ceramic bridges made by dental
students occur during root canal preparation of abutment teeth.
PMID- 9758398
TI - The variability of bite force measurement between sessions, in different
positions within the dental arch.
AB - The effect of measuring bite force with different patterns of transducer on
different occasions was studied. Maximum voluntary bite force was measured in
eight volunteers. Three transducer positions, each with a different pattern of
transducer, were used; between the anterior teeth, between the second premolar
and the first molar on one side and between the second premolars and first molars
on both sides. Visual feedback of force was provided. Two sets of five maximum
clenches were recorded with a rest period in between. This sequence was repeated
for each transducer and the experiment was repeated on three different days. The
highest forces were measured with the bilateral posterior transducer (mean 580 N,
s.d. 235) and the lowest on the anterior transducer (mean 286 N, s.d. 164). The
standard deviations of the bite force mean values were used as an indication of
the variability and were subjected to a non-parametric anova (Kruskal-Wallis).
The forces recorded with each transducer position were significantly different
between the transducers (P < 0.01) and the maximum bite force showed least
variability when measured between the posterior teeth on one side only. There was
little difference in bite force between the three different sessions (P > or =
0.05) when measured in the same position within the dental arch, whichever of the
three positions that may be.
PMID- 9758399
TI - Macroscopic osseous changes in the temporomandibular joint related to dental
attrition in Japanese macaque skull.
AB - The purpose of this study was to investigate the relationship between osseous
changes in the temporomandibular joint (TMJ) and dental attrition in the Japanese
macaque. One hundred and thirty Japanese macaque skulls (54 male and 76 female)
from animals which had been bred in the same environment, were randomly sampled
from a collection at the Primate Research Institute of Kyoto University. The age
at death had been recorded in all cases. TMJ osseous changes were independently
evaluated by three examiners, and were defined as an irregular surface or a
perforated compact bone layer with a markedly irregular surface on either the
temporal or condylar components. Age was a significant factor in predicting TMJ
osseous changes (P < 0.001). A strong relation was observed between age and
dental attrition (P < 0.001), while dental attrition was not a significant factor
in predicting TMJ osseous changes (P = 0.334). The prevalence TMJ osseous changes
in male animals was slightly higher than in females (P = 0.057). The results of
this study suggest that osseous changes in the macaque TMJ are mainly related to
age, not to dental attrition.
PMID- 9758400
TI - Bond strength of photocured composite resin facings: clinical versus laboratory
procedures.
AB - The tensile strengths of laboratory versus clinical photocured composite resins
have been investigated. Metal surfaces were bonded to photocured composite resin
by either retentive beads, Sebond or Silicoating. The bond strengths were
measured by an Instron machine and the fracture sites observed. Following repair
with the adhesives Dentacolor Opaquer, Fusion and Cover up 2, the Instron
measurements were repeated. The metal/facing bond strength was the highest in
samples fabricated by the Silicoating technique, the bond strength exceeding the
cohesive forces in the composite resin facing. The tensile strengths of
metal/facing bonded by Sebond and retentive beads were similar. Fractures that
include the facing and partially reveal the metal are the least resistant to
tension after repair. Renewal of the Opaque layer and completion of the facing is
superior to any of the repair methods used in this paper. The original fracture
point is the weakest after repair. All the repair kits tested were inferior to
the original restoration materials.
PMID- 9758401
TI - Effects of different surface treatment methods on the bond strength of composite
resin to porcelain.
AB - In this study failures of composite resin/ porcelain interfaces under shear
loading were examined. Porcelain firing were made onto metal cylinders and
porcelain surfaces were roughened with burrs or treated with hydrofloric acid gel
and/ or sandblasted with a Microetcher. Two silane coupling agents were used in
five groups, each of which had 22 samples. All of the treated samples were
restored with a hybrid-type composite resin. Then each group was divided into two
subgroups according to storage times of 24 h and 30 days. After thermocyling the
samples which were stored for 30 days, all of the groups were subjected to shear
force at the composite resin/porcelain interface until fracture occurred. The
results showed that there were differences both in the 24-h and 30-day storage
period bond strengths between the various surface treatment methods. The samples
treated with all three of the Microetcher, hydrofloric acid and silane exhibited
the highest shear bond values after 24 h storage, followed by the
microetched/silane and the hydrofluoric acid/silane groups (F: 570.31, P: 0.00).
After 30 days, the highest mean shear bond strength values were again with
samples treated by all three processes. The storage period and thermocycling
decreased the bond strength of samples, however, there was a significant
difference among groups (F: 1388-55, P: 0.00). Silane pre-treatment of porcelain
was important as the mean bond strength of sandblasted/etched specimens were
significantly lower than the other groups which were treated mechanically, in 24
h. Sandblasting seems to have little effect on the bonding. The comparison of 24
h and 30-day samples have also significant difference (F: 91.4376, P: 0.00).
PMID- 9758403
TI - The effect of diabetes mellitus on histopathological changes in the tissues under
denture base and without mechanical pressure.
AB - Histopathological changes in the tissues under a denture base were studied with
respect to the difference between diabetic and normal rats. Diabetes mellitus was
induced in Wistar rats by streptozotocin. The experimental denture base was
designed to make contact with the palatal mucosa without any continuous nor
masticatory pressure. Histopathological observation periods were 1, 2, 4, 8, 12
and 20 weeks after the insertion of the denture base. Histopathological
examination revealed that only the transient slight proliferative reaction
observed in mucosal epithelium under a denture base in normal non-diabetic rats,
was lessened by induced diabetes mellitus. Moreover, covering the palatal mucosa
with a denture base without any continuous nor masticatory pressure and with the
maintenance of mucosal cleanliness under it and of the denture itself, did not
cause any inflammatory change or bone resorption in the tissues under the base.
PMID- 9758402
TI - Physical mechanisms involved in the genesis of temporomandibular joint sounds.
AB - Several different mechanisms are potentially capable of generating sounds in the
temporomandibular joint (TMJ). These include impact, sliding and stick-slip
friction, fluid dynamic effects and the release of elastic strain energy. It is
the aim of this paper to provide a framework with which to separate sounds
resulting from the different underlying causes. Each mechanism is described and
its relevance to TMJ sounds and clinical significance discussed. Since it is not
possible to observe these mechanisms in vivo the arguments are based mainly on
analogies which are used to make predictions of the characteristic acoustic
signatures of the sounds produced by these different mechanisms. In particular
the changes in the characteristics of the sounds as parameters such as mandibular
speed and loading are stressed. It is suggested that single short duration sounds
(clicks) are due to impact, multiple short duration sounds (creaks) to stick-slip
friction and defects of form and long duration sounds (crepitus) to simple
sliding friction. Several other mechanisms which have no obvious clinical
significance but which are capable of producing similar sounds are also described
and methods of distinguishing them from the sounds that do have clinical
implications are discussed.
PMID- 9758404
TI - The effect of parafunction on condylar asymmetry in patients with
temporomandibular disorders.
AB - This study was undertaken to examine the relationship between condylar asymmetry
and parafunction in patients with temporomandibular disorders (TMD). Twenty-eight
patients with TMD and parafunction and 30 patients with TMD but no parafunction
were examined. A panoramic radiograph was obtained for each patient and from this
the condylar asymmetry determined. The group with parafunction showed a
significantly (P < 0.005) higher asymmetry index than did the group with no
noticeable parafunction. Patients were grouped into the following age ranges: 10
19 years, 20-29 years, 30-39 years, and 40 + years. The mean asymmetry index was
determined for each age range for both groups of patients. The group of patients
with TMD and parafunction had a higher mean asymmetry index in all the age ranges
studied. This suggests that muscle hyperactivity may be a factor in the increased
asymmetry found in patients with TMD.
PMID- 9758405
TI - Effect of denture thickness on tooth movement during processing of complete
dentures.
AB - In this investigation the effect of denture thickness on tooth movement during
processing of complete dentures was studied. A maxillary cast from a patient was
duplicated to obtain 10 identical casts. Base plates were constructed on five
casts using 1.25 mm thick wax. Base plates were constructed on the other five
casts using 2.5 mm thick wax. Teeth were placed on the ridge of each cast and a
TMS pin was placed vertically, upright, in each tooth. The dentures were
invested, cured, decasted, finished and polished. Each denture was radiographed
immediately before processing, after deflasking, on removal from the cast and
after finishing and polishing using a standard technique. The radiographs were
digitized using an Eikonix image digitizer. The results showed that there were
significant variations in tooth movement between thick and thin denture bases.
Also an increase in the molar-to-molar distance was found in both the thin and
thick dentures but the magnitude of tooth movement was more in thick dentures.
PMID- 9758406
TI - CD8+ cytolytic T lymphocytes and the skin.
AB - T lymphocytes show a special affinity for the skin. Although the roles played by
the CD4+ population of T lymphocytes in immunodermatology were so far actively
investigated, much less is known about the roles played in the skin by CD8+
cytolytic T lymphocytes (CTL). The activity of CD8+ CTL in the
immunodermatological context, however, is likely to be most important; the immuno
biology itself of CD8+ CTL, moreover, although far from being fully understood,
shows intriguing characteristics. Immunophenotype, function and cytokine profile
of CD8+ CTL are overviewed in the first section of this review. Phenotypically,
not only CD8+ CTL can be subdivided into CD8+ CD28+ CD11b- and CD8+ CD28- CD11b+
subsets, but also an up-to-now undetected CD8+ CD28- CD11b- subset does exist.
Functionally, not only "cytotoxic" but even "suppressor" subpopulations have been
shown to exert cytolytic capabilities indeed, and "suppression" itself may be due
to such a lytic capacity. According to cytokine synthesis, CD8+ CTL can be split
into Tc1 and Tc2 subsets, each able to influence specific patterns of immune
responses. The impact of CD8+ CTL in immunodermatology, overviewed in the second
section of the current review, is crucial. The pathophysiology of inflammatory
dermatoses is deeply influenced by the activity of CD8+ CTL: e.g., CD8+ CTL
within psoriatic epidermis are possibly associated to the persistence of
psoriatic lesions not undergoing resolution; on the other hand, in late lesions
of lichen planus CD8+ CTL predominate, thus explaining presumably both the
cytolytic attack against keratinocytes and the modulation of the inflammatory
reaction up to the final resolution of the lesions, Tc1 cells are decreased in
atopic dermatitis, and such a decrease can account both for IgE overproduction
and for development of infections. Finally, CD8+ CTL can sustain against
cutaneous viruses/tumors cytolytic immune responses not only of secondary but
even of primary type, i.e. induced by Langerhans cells/dendritic cells either
transfected or pulsed with skin virus/tumor-associated antigens, thus allowing
the production of vaccines against cutaneous viral/neoplastic diseases.
PMID- 9758407
TI - The millennium criteria for the diagnosis of atopic dermatitis.
AB - Atopic dermatitis forms an active area of basic and clinical research, where
important new knowledge about genetics and immunopathogenesis has surfaced over
the past years, and where simultaneous development of new and innovative
therapies is under way. However, the inclusion of any patient in an atopic
dermatitis study, whether it is on its genetics, pathogenesis or therapy,
requires a diagnosis which is irrefutable. Since there is no simple and also no
complicated laboratory procedure to reach a diagnosis of atopic dermatitis,
different sets of clinical criteria have been developed for the purpose of making
the diagnosis uniformly in different studies as well as in different study
centers. The most commonly used are Hanifin and Rajka's set of diagnostic
features, which have major and minor clinical criteria to be fulfilled in order
to establish a diagnosis of atopic dermatitis. Recent developments in the
immunology of atopy have clearly established the major abnormality in this
syndrome, the preferential production of allergen-specific IgE. In this
contribution, it is suggested that the presence of such antibodies in a given
patient should be a mandatory criterium for the diagnosis of atopic dermatitis.
Such a diagnostic test however establishes a diagnosis of atopic syndrome, not
atopic dermatitis. Thus, for atopic dermatitis we have to rely, for the time
being, on additional clinical criteria. The clinical features described in the
literature are critically evaluated, and it is suggested that in addition to the
mandatory presence of allergen-specific IgE, 2 of 3 principal criteria (pruritus,
typical morphology and distribution, chronic or chronically relapsing) should be
present for such a diagnosis. Finally, the minor features originally described by
Hanifin and Rajka and later evaluated by others are revised and divided over 4
subcategories; a) related to subclinical eczema; b) related to dry skin; c) extra
skin folds; and d) ophthalmological pathology. They are suggested to be used as
additional criteria only, needed when clinical suspicion is high but the new
mandatory and principal diagnostic criteria described here are inconclusive. For
study purposes, we suggest that the mandatory and principal criteria are
sufficient. They are now evaluated and validated in ongoing atopic dermatitis
treatment studies.
PMID- 9758408
TI - Most chronic urticaria is food-dependent, and not idiopathic.
AB - Although chronic urticaria is generally thought to be mostly idiopathic, we have
recently provided convincing evidence that in the majority of patients, food
ingredients provoke the symptoms and sustain the disease. On a diet largely
avoiding preservatives, dyes and natural pseudoallergens, 73% of patients
experienced remission of more than 6 months duration, starting within the first 3
weeks after initiation of the diet. This response rate is clearly higher than the
reported 24% spontaneous remission rate over the same time period. The
specificity of the dietary effect was proven 1) by double-blind provocation with
pureed pseudoallergen-low versus -rich food and 2) by induction of a clinical
response to a 3-week diet low in pseudoallergens, but not to a standard diabetes
diet in 3 patients studied in a double-blind crossover design. On double-blind,
placebo controlled oral provocation, only 18% of diet-responsive patients reacted
to known food preservatives and dyes, but 71% to pureed tomatoes and 44% to their
steam extracts. These findings identify naturally occurring pseudoallergens in
food as major elicitors of chronic urticaria. In contrast, autoantibodies against
Fc epsilonRIalpha have been identified in only about 30% of chronic urticaria
patients, and evidence for their truly causative role is still lacking since
therapeutic measures work in patients irrespective of the presence or absence of
the autoantibodies. For both food intolerance and Fc epsilonRIalpha
autoantibodies in chronic urticaria, the associated pathomechanisms are however
still in need of clarification. Meanwhile, the diet-responsiveness in the
majority of patients opens new perspectives for the management of chronic
urticaria.
PMID- 9758409
TI - What controls melanogenesis?
AB - The pigments eumelanin and pheomelanin are the visually most striking products of
specialized neural crest-derived cells (melanocytes), and provide color to both
epidermis and hair shafts. While the intriguing and controversial biological
functions of these multifaceted heteropolymers will be discussed in a later
feature, here it is explored how their generation (melanogenesis) is controlled.
For decades, this has been the object of much controversy, the salient features
of which are delineated in the following contributions.
PMID- 9758410
TI - Release of monocyte chemoattractants by polymorphonuclear leukocytes stimulated
by their adhesion to stratum corneum opsonized via complement activation,
measured with a human acute monocytic leukemic cell line, THP-1.
AB - Stratum corneum (SC) exposed to living tissues, induces inflammation
characterized by the formation of mixed cell granulomas consisting of
infiltrative polymorphonuclear leukocytes (PMNs) and monocytes/macrophages. In
this study, to clarify the mechanism for the later monocyte accumulation in SC
induced granulomas, we evaluated monocyte chemotactic activity induced by PMNs
treated with serum-opsonized SC by using a human acute monocytic leukemic cell
line, THP-1. When the supernatant was obtained from a PMN suspension cultured
with opsonized plantar SC, higher THP-1 chemotactic activity was detected as
compared with that cultured with non-opsonized SC. Although some concentrations
of the chemokines, MIP-1alpha and MIP-1beta, were detected in supernatants
obtained from the PMN suspensions cultured with plantar SC than in the control
suspensions of PMN alone, their production by PMN was not influenced by the
opsonization procedure. In contrast, MCP-1 was found to be secreted from PMN
suspensions constitutively, showing no correlation to this THP-1 chemotactic
activity. Moreover, HPLC analysis of PMN suspensions indicated that factors with
far higher molecular weight values than these chemokines are involved in the
chemotaxis of THP-1 cells.
PMID- 9758411
TI - Decreased interleukin-7 and transforming growth factor-beta1 levels in blister
fluids as compared to the respective serum levels in patients with bullous
pemphigoid. Opposite behavior of TNF-alpha, interleukin-4 and interleukin-10.
AB - This study analyzes both the blister fluid (BF) and serum levels of IL-7 and TGF
beta1 in samples from 18 patients affected with bullous pemphigoid (BP). These
cytokines clearly present lower concentrations (P<0.001) in BFs than in the sera
(1/20 and 1/2, respectively). In contrast, TNF-alpha, IL-10 and IL-4 present
increased amounts in BFs that were 12, 12 and 17-fold, respectively. Eighteen
sera (and 10 suction BF) from normal individuals were also employed as control.
Normal sera presented significantly lower serum IL-7 concentrations than BP,
while no significant TGF-beta1 variations were observed between normal and
pathologic serum samples. In addition, the serum levels detected in BP patients
were significantly correlated with disease intensity (r=0.64, P=0.003, evaluated
as the number of blisters/erosions for each patient) as well as with the
peripheral B-lymphocyte counts (r=0.80, P<0.001) and antibodies directed against
the basement membrane zone (r=0.65, P<0.005). Although a clear explanation of
this phenomenon is lacking, the data presented in this report agree with a strong
decrease of IL-7 production at the local level (keratinocyte is known to produce
IL-7 and the latter is known to be down-regulated by IL-10, and in other models
also by TGF-beta1 and IL-4, whose levels are elevated in BP BFs) as opposed to an
increased peripheral release of the same modulator. The IL-7 reduction may have a
biological relevance in controlling a chronic, progressive disease.
PMID- 9758412
TI - The influence exerted by cutaneous ligands in subjects reacting to nickel sulfate
alone and in those reacting to more transition metals.
AB - To study the influence exerted by cutaneous ligands in nickel reactions we have
evaluated the patch tests responses to 4 aqueous nickel salts (sulfate, chloride,
nitrate, acetate) able to form different complexes with different geometry. Two
groups of respectively 71 subjects who previously reacted only to nickel sulfate
5% petrolatum (pet) and of 30 subjects who previously reacted to nickel sulfate
5% pet and to at least 1 other transition metal, were simultaneously repatch
tested to 200 microg of Ni++ contained in nickel sulfate in pet and to 47 microg
of Ni++ contained in 4 different aqueous nickel salts. Another 2 groups of 25
subjects with the same characteristics were simultaneously repatch tested to 200
microg of Ni++ in pet and to 12 microg of aq Ni++ as in the first 2 groups.
Visual score, total score, and mean value of the reactions were utilized in
evaluating the degree of the responses. On testing to 200 microg of Ni++ in pet
all the subjects were able to give positive responses. Whilst a higher percentage
of the responses of 2+ degrees was found in subjects reacting to nickel sulfate
5% pet alone, a higher percentage of responses of 3+ degrees was observed in
subjects reacting to more transition metals. On testing to 47 and 12 microg of
aqueous Ni++ a large variability of responses to the single salts was observed in
all the subjects. However, in subjects reacting to more metals there were either
a greater number of multiple responses to 3 or 4 salts or responses stronger than
those found in subjects reacting to nickel sulfate alone. Although patch testing
cannot give us complete information about the degree of previous exposure, the
results arising from the tests seem to demonstrate that the subjects allergic to
nickel and other transition metals are more reactive than the subjects allergic
only to nickel to the application of the same amounts of Ni++ contained in
different salts. When considering the QSAR model, the difference in the
sensitizing potential of the metal at the same penetration properties can depend
on the possibility of combining with specific ligands. Therefore, it is likely
that in subjects reacting to more metals there is a more uniform availability of
cutaneous ligands which conditions the formation of complexes more immunogenic.
The arising inflammatory reaction in these cases leads to a stronger but less
specific response.
PMID- 9758413
TI - Expression of the anhidrotic ectodermal dysplasia gene is reduced in skin cancer
coinciding with reduced E-cadherin.
AB - X-linked anhidrotic ectodermal dysplasia (EDA) is characterized by defects in the
development of hair, teeth, and sweat glands. We have recently cloned the gene
for EDA by positional cloning. The EDA gene encodes a transmembrane protein with
a putative role in epithelial mesenchymal interactions. Since EDA could play a
role in cell-cell or cell-matrix adhesion, acantholytic skin diseases and several
types of non-invasive and invasive skin cancers were studied using in situ
hybridization. Because of the observation that the promoter region of the EDA
gene contains a binding site for LEF-1, which is involved in the signaling
through E-cadherin/beta catenin complex, we compared the expression of EDA with
immunolocalization for E-cadherin (E-CD). EDA expression during hair growth
cycle, in benign adnexal tumors, and neuroectoderm-derived nevus cells was also
examined. Our findings indicate that EDA expression is less abundant in malignant
tumors, including basal and squamous cell carcinomas and melanoma, and in
acantholytic keratinocytes compared to normal epidermis. The reduction in
expression also coincides with diminished E-CD staining in all malignant cell
types and in acantholytic cells. Our results suggest that EDA protein functions
in the regulation of epithelial cell contacts and that it may be associated with
the E-CD signaling pathway.
PMID- 9758414
TI - CD24 expression on human keratinocytes.
AB - CD24 or Nectadrin is a cell surface glycoprotein expressed in pre-B lymphocytes,
T lymphocytes, neurons, muscle cells and carcinoma cells. Its function is not
completely known, but it has been suggested that it is involved in cell adhesion
and signalling. CD24 has recently been identified as the human molecule
homologous to the murine heat-stable antigen (HSA). HSA is expressed by murine
keratinocytes and delivers costimulatory signals in T-cell activation. Long-term
cultures of normal human keratinocytes (HKC) were obtained from skin of human
female breast sections and either left untreated or were treated with phorbol-12
myristate-13-acetate (PMA) at 10-100 ng/ml, calcium 0.5-2 mM or IFN-gamma 100
1000 U/ml, for 24-48 h. Using RT-PCR and flow cytometry we showed that HKC
express low levels of CD24 even under basal conditions, and the treatment with
calcium, PMA or IFN-gamma increased levels of CD24 mRNA and protein. To the best
of our knowledge, this is the first report to measure CD24 expression and
production by cultured HKC in basal conditions and after stimulation. Further
studies are needed to determine biological and therapeutical relevance of these
findings.
PMID- 9758415
TI - Camptothecin induces differentiation, tissue transglutaminase and apoptosis in
cultured keratinocytes.
AB - Cultured normal human adult keratinocytes were exposed to (S)-(+)- camptothecin
over the concentration range 10(-5) to 10(-10) M. The dose-dependent inhibition
of growth was recorded using cell counting. The induction of terminal
differentiation was demonstrated by the relative increase in squamous and
cornified cells, and the concomitant decrease in small, proliferative cells, with
an overall decrease in total cell numbers on going from 10(-10) to 10(-6) M
concentration of the drug. The induction of apoptosis was studied by assay of two
types of transglutaminase, "tissue" and "keratinocyte", and by assay of histone
linked mono- and oligonucleosomes. Induction of apoptosis was accompanied with
increase in "tissue" transglutaminase and in the amount of nucleosomes, the
latter being indicative of endonuclease activity. This activity was sharply
increased at a camptothecin concentration of 10(-5) M, and may have been
facilitated by "tissue" transglutaminase at lower concentrations. The data
suggest that camptothecin restricts keratinocyte growth by several mechanisms
including apoptosis and emphasize its possible use in topical therapy for
psoriasis.
PMID- 9758416
TI - Cell migration and MMP-9 secretion are increased by epidermal growth factor in
HaCaT-ras transfected cells.
AB - Mutated RAS oncoproteins and epidermal growth factor (EGF) are thought to
contribute to the proliferative, invasive and metastatic properties of
transformed cells. In the present study, we investigated the role of EGF in two H
ras transfected clones and compared it to that in the parental cell line, HaCaT
and primary cultured keratinocytes. Our findings show that the motility on type I
collagen, measured by the migration index, was similar for both the HaCaT cell
line and normal human keratinocytes, whereas it was higher for the HaCaT-ras
clones. These results suggest an involvement of the ras oncogene in the
stimulation of cell migration. EGF in cell pretreatment or during the migration
assay also caused an increase in migration of all the cells, but preserved the
difference between HaCaT and HaCaT-ras. However, no significant difference in EGF
R expression was detected between normal cultured keratinocytes, HaCaT and HaCaT
ras cell lines with or without EGF pretreatment. Moreover, when the cells were
stimulated with EGF, the MMP-9 activity was greatly increased in a dose-dependent
manner in all the cells, and EGF stimulation particularly highlights the
increased amount of MMP-9 in HaCaT-ras cells compared to HaCaT cells. In
conclusion, EGF is able to enhance motility and to up-regulate MMP-9 activity in
all cells, but with a higher impact in HaCaT-ras cells without an overexpression
of EGF-R. As EGF acts in synergy with the H-ras mutation, they could be
implicated in the local invasion by the HaCaT-ras clones.
PMID- 9758417
TI - Immunohistochemical investigation of evolving inflammation in lesions of acne
vulgaris.
AB - The mechanisms involved in the development of inflammation in acne vulgaris have
yet to be elucidated. Previous studies have shown that the initial cellular
infiltrate in early inflammatory lesions is mononuclear, predominantly CD4
positive T cells. The aims of this study were to investigate the pattern of
expression of adhesion molecules and HLA-DR in evolving acne lesions. Forty-nine
patients with moderate to severe acne were biopsied following lesion mapping.
Lesions were classified according to their duration of inflammation as up to 6 h,
from 6 to 24 h, from 24 to 48 h and from 48 to 72 h. The cellular infiltrate was
determined using monoclonal antibodies to CDI, CD3, CD4 and CD8. The expression
of ICAM-1, E-selectin. VCAM-1 and HLA-DR was determined. Early (6 h) lesions had
perivascular CD3 positive T-cell infiltrates which were predominantly CD4
positive. This was associated with vascular expression of ICAM-1, E-selectin,
VCAM-1 and HLA-DR. Periductal infiltrates were present in 70% of the early
lesions (up to 6 h). The cells were predominantly CD4 positive and associated
with a high level of HLA-DR and ICAM-1 expression. Periductal infiltration
increased with time and persisted to 72 h. ICAM-1 and HLA-DR were expressed
epidermally in early and late lesions. CD1 positive cells were a minor, but
consistent element in the perivascular and periductal infiltrates of early and
late lesions. There was no statistically significant difference in the levels of
expression of E-selectin, VCAM-1, ICAM-1 or HLA-DR for lesions of different
duration. The pattern of HLA-DR and adhesion molecule expression plus the nature
of the cellular infiltrate supports the hypothesis that inflammation in acne is
mediated by CD4 positive T cells.
PMID- 9758418
TI - Human tyrosinase related protein-1 (TRP-1) does not function as a DHICA oxidase
activity in contrast to murine TRP-1.
AB - Tyrosinase related protein-1 is a melanocyte specific protein and a member of the
tyrosinase gene family which also includes tyrosinase and TRP 2 (DOPAchrome
tautomerase). In murine melanocytes, TRP-1 functions as a 5,6-dihydroxyindole-2
carboxylic acid [DHICA] oxidase during the biosynthetic conversion of tyrosine to
eumelanin and mutations affecting TRP-1 result in the synthesis of brown rather
than black pelage coloration. In this study, we examined the putative DHICA
oxidase activity of TRP-1 in human melanocytes using several approaches. We first
utilized a line of cultured melanocytes established from a patient with a form of
oculocutaneous albinism completely lacking expression of TRP-1 (OCA3). This line
of melanocytes endogenously exhibited the same amount of DHICA oxidase activity
as control melanocytes expressing TRP-1. In other experiments, cultured human
fibroblasts were transfected with a cDNA for TRP-1, in either the sense or
antisense direction, or with the retroviral vector alone. TRP-1 expression was
induced in fibroblasts transfected with the TRP-1 cDNA in the sense direction
only. Although TRP-1 was expressed by sense-transfected cells, there was no
significant DHICA oxidase activity above controls. These results demonstrate that
human TRP-1 does not use DHICA as a substrate for oxidation.
PMID- 9758419
TI - Increased sensitivity to peroxidizing agents is correlated with an imbalance of
antioxidants in normal melanocytes from melanoma patients.
AB - We have previously shown an imbalance of the antioxidant system in some cultures
of normal melanocytes from patients with melanoma. In order to evaluate if the
alteration of the antioxidants could be the basis of an increased sensitivity to
exposure to peroxidative agents, in cultured melanocytes from normal individuals
(n = 11) and from patients with melanoma (n = 11), superoxide dismutase and
catalase activities were evaluated by spectrophotometer, and the levels of
vitamin E and of the polyunsaturated fatty acid of cell membranes were determined
by gas chromatography mass spectrometry. In 5 out of the 11 cultures of
melanocytes from melanoma patients, with respect to those from normal
individuals, a significant decrease of catalase activity (Cat) associated with an
increase of vitamin E (Vit E) concentration was found, whereas no significant
modification of superoxide dismutase activity (SOD) was observed. A wide range of
variability was detected in the percentage of the polyunsaturated fatty acids of
the cell membranes and a correlation was found between the ratio SOD/Cat and the
percentage of linoleic acid, indicating that the imbalance of the enzymatic
antioxidants leads to a lipoperoxidative process. The electron microscopic
examination of these cultures revealed many microvilli in the plasma membranes
and nuclear infoldings and in the cytoplasm light vacuoles. Moreover some cells
contained several dense bodies with a round shape and numerous spherical lamellae
possibly representing immature melanosomes. Treatment with cumene hydroperoxide
between 0.66 and 20 microM did not produce a significant modification of cell
viability in melanocytes from normal individuals. On the contrary in melanocytes
from melanoma patients correlated with the ratio Vit E/Cat, considered as a
parameter of the antioxidant imbalance, a stimulatory effect was observed at 0.66
microM CUH and a cytotoxic effect at 20 microM. In conclusion our results suggest
that a constitutional alteration of the scavenger system could be present in
normal melanocytes from melanoma patients and that this could be the basis for an
increased sensitivity to pro-oxidant agents.
PMID- 9758420
TI - Identification of beta-endorphin, alpha-MSH and ACTH peptides in cultured human
melanocytes, melanoma and squamous cell carcinoma cells by RP-HPLC.
PMID- 9758421
TI - Risk revisited.
AB - As our knowledge of dental caries and periodontal diseases has increased, our
perspective has changed from viewing these diseases as ubiquitous to one which
sees a variety of risk profiles in a population. Now, from a perspective of
assigning risk, caries and periodontitis can be thought to be more like some of
our common medical conditions, i.e., certain people or subgroups of the
population are at higher risk than others and that prevention and intervention
involve a combination of personal behaviors and professional practices. Research
into risk assessment, however, is often hampered by confusing and ambiguous use
of terminology. This commentary proposes some specific definitions for terms used
in risk assessment in dentistry. These terms include risk factor, risk indicator,
demographic risk factor, risk predictor (risk marker), prognostic factor, risk
model, and prediction model.
PMID- 9758422
TI - Factors associated with adult periodontitis in a dental teaching clinic
population.
AB - Exposure to a number of environmental, behavioral and sociodemographic variables
has been associated with increased prevalence and severity of adult
periodontitis. However, it is not possible easily to identify the individuals
most susceptible to this chronic disease. A case control study was conducted
among a population of adults to determine what factors were associated with
increased prevalence of moderate to advanced periodontitis. Clinical and
radiographic data were obtained from dental charts and structured interviews were
conducted by telephone to collect sociodemographic and behavioral data.
Statistical modeling was completed for the total study population (35-87-year
olds) and for two age-stratified subpopulations. Significant crude disease
associations were observed between periodontitis and numerous explanatory
variables. However, after adjustment for age and gender, few variables remained
significant. Age stratification indicated that young adults (35-54 years) were
affected differently from older adults (> or =55 years) by exposures to certain
variables. Young moderate smokers had a 3.15 times increased risk of
periodontitis and young heavy smokers had a 7.33 times increased risk compared to
never-smokers. Older single adults had a 3.07 times increased risk compared to
those with partners.
PMID- 9758423
TI - Evaluation for an observation effect in a prospective cohort study of oral health
outcomes.
AB - OBJECTIVES: Evaluation for changes in behavior due to research participants'
knowledge that behavior is being observed (also referred to as a Hawthorne effect
or reactivity) has received little attention in the dental literature. The
Florida Dental Care Study, a prospective, non-randomized, longitudinal study of
oral health outcomes, provides some inferential power to evaluate for an effect
on dental care use due to participants' knowledge that this behavior was being
observed. The purpose of this paper is to document that an observation effect can
occur in dental studies, and to estimate its magnitude in four groups that were
defined by their typical approach to dental care as stated at baseline:
consistent regular attenders (CRAs); inconsistent regular attenders (IRAs);
consistent problem-oriented attenders (CPOAs); and inconsistent problem-oriented
attenders (IPOAs). METHODS: At baseline, 873 respondents with at least one
natural tooth and who were 45 years of age or older participated for an interview
and clinical dental examination. Respondents were asked about their dental care
use in general and check-up use in particular at 6-month intervals over a period
of 24 months. RESULTS: Dental care use in general and check-up use in particular
varied across time points and across the four groups of the sample. There was
some stimulation in dental care use for the sample overall, but by the 18-to-24
month period, use had returned to baseline levels. In a direction opposite from
that hypothesized, results from the CRAs suggested decreased use of dental care
over the course of the 24 months of observation. No consistent pattern was
evident for the IRAs, CPOAs, or IPOAs. CONCLUSIONS: An observation effect was
evident, but was modest in magnitude and differed within and between sub-groups
of the sample. While self-selection into dental care user groups is an expected
and desirable feature of this design, the size of the user/non-user groups was
affected for some subgroups. We conclude that dental care studies with the
potential for an observation effect should evaluate for this effect by
distinguishing sub-groups of the sample based on their propensity (as stated at
baseline) to use dental care. These differential effects across sub-groups should
be taken into account as inferences are made.
PMID- 9758424
TI - Fluorosis risk from early exposure to fluoride toothpaste.
AB - Swallowed fluoride toothpaste in the early years of life has been postulated to
be a risk factor for fluorosis, but the epidemiological evidence is weakened by
the fact that most of the relevant studies were done in developed countries where
an individual is exposed to multiple sources of fluoride. OBJECTIVES: To quantify
the risk of fluorosis from fluoride toothpaste in a population whose only
potential source of fluoride was fluoride toothpaste. METHODS: Case-control
analyses were conducted to test the hypothesis that fluoride toothpaste use
before the age of 6 years increased an individual's risk of fluorosis. Data came
from a cross-sectional clinical dental examination of schoolchildren and a self
administered questionnaire to their parents. The study was conducted in Goa,
India. The study group consisted of 1189 seventh grade children with a mean age
of 12.2 years. RESULTS: The prevalence of fluorosis was 12.9% using the TF index.
Results of the crude, stratified, and logistic regression analyses showed that
use of fluoride toothpaste before the age of 6 years was a risk indicator for
fluorosis (OR 1.83, 95% CI 1.05-3.15). Among children with fluorosis, beginning
brushing before the age of 2 years increased the severity of fluorosis
significantly (P<0.001). Other factors associated with the use of fluoride
toothpaste, such as eating or swallowing fluoride toothpaste and higher frequency
of use, did not show a statistically significant increased risk for prevalence or
severity of fluorosis. CONCLUSIONS: Fluoride toothpaste use before the age of 6
years is a risk indicator for fluorosis in this study population.
PMID- 9758425
TI - Estimation of optimal concentration of fluoride in drinking water under
conditions prevailing in Chile.
AB - The purpose of this comparative study of caries and dental fluorosis experience
in Chilean children was to estimate the optimal range of fluoride concentration
in tap water under conditions currently prevailing in Chile. The sample included
2431 schoolchildren 7, 12 and 15 years old, life-long residents of five
communities with fluoride concentrations in their tap water in the range 0.07-1.1
mg/L. The study population received an oral clinical examination including caries
experience and an enamel fluorosis evaluation of the permanent dentition (Dean's
scoring system). For 15-year-old children, the DMFT index changed from 5.06 to
2.60, and for 12-year-olds it changed from 3.10 to 1.36 when fluoride water
concentration changed from 0.07 to 1.10 mg/L. For 7-year-old children the dmft
index correspondingly changed from 3.67 to 1.59. The relationship between DMFT
for 12-year-olds and water fluoride concentration was best fitted by a
logarithmic function (r2=0.98). The Community Fluorosis Index (CFI) was used to
assess enamel fluorosis in the study population, and it showed a linear
relationship (r2=0.983) with increasing fluoride concentration of water for the
12-year-old group. Results obtained suggest that under current Chilean
conditions, the optimal range of fluoride concentration in potable water should
lie in the 0.5-0.6 mg/L range.
PMID- 9758426
TI - Caries frequency in permanent teeth before and after discontinuation of water
fluoridation in Kuopio, Finland.
AB - The piped water of Kuopio, Finland, was fluoridated in 1959. Owing to strong
opposition by different civic groups, water fluoridation was stopped at the end
of 1992. OBJECTIVES: The aim of this study was to examine the consequences of the
discontinuation on dental health. METHODS: In 1992 and 1995, independent random
samples of all children aged 6, 9, 12 and 15 years were drawn from Kuopio and
Jyvaskyla, a nearby low fluoride town whose distribution of demographic and socio
economic characteristics was fairly similar to Kuopio's. The total number of
subjects examined was 550 in 1992 and 1198 in 1995. Caries was registered
clinically and radiographically by the same two calibrated dentists in both
towns. RESULTS: In 1992, the mean DMFS values were lower in the fluoridated town
for the two older age groups, the percentage differences for 12- and 15-year-olds
being 37% and 29%, respectively. For the two younger age groups no meaningful
differences could be found. In 1995, the only difference with possible clinical
significance was found in the 15-year-olds in favor of the fluoridated town
(18%). In 1995, a decline in caries was seen in the two older age groups in the
nonfluoridated town. In spite of discontinued water fluoridation, no indication
of an increasing trend of caries could be found in Kuopio. The mean numbers of
fluoride varnish and sealant applications decreased sharply in both towns between
1992 and 1995. In spite of that caries declined. CONCLUSIONS: These findings
suggest that the decline of caries has little to do with professional preventive
measures performed in dental clinics.
PMID- 9758427
TI - Caries preventive services for children and adolescents in Denmark, Iceland,
Norway and Sweden: strategies and resource allocation.
AB - According to the dental acts of Denmark, Iceland, Norway and Sweden, emphasis is
placed on preventive dental care. The purpose of this study was to describe and
compare two aspects of the caries preventive services: the strategies and the
resource allocation for preventive dental care of children and adolescents in
Denmark, Iceland, Norway and Sweden. Questionnaires were sent to samples of
dentists and other dental personnel who provided preventive care to children
during 1995 and 1996. Comparisons between the countries showed significant
differences in recall routines and in implementation of risk-based and population
based preventive strategies. Multivariate analyses showed that the time used for
preventive care varied by country and was not associated with the DMFT of the
children. More time was allocated for prevention when more operating dental
auxiliaries were available at the clinic, when the recall interval was shorter,
when the time used for routine examination was longer and when the clinician was
an auxiliary rather than a dentist. In conclusion, resource allocation and
strategies used for prevention were not consistent between the countries.
PMID- 9758429
TI - Cost and productivity analysis of orthodontic care in Finland.
AB - The aim of the study was to investigate the costs of orthodontic care provided
for children and adolescents up to the age of 18 by municipal health centers in
Finland, and to study the productivity of these services. The data were gathered
by a questionnaire sent to all health centers; 96% responded. The majority of
respondents estimated the share of orthodontic care as 10% of the total gross
costs of dental care, given that 14% of all dental visits were for orthodontic
reasons. To study the productivity in individual health centers, the output was
measured by the estimated number of completely treated patients. The cost of
orthodontic treatment per completely treated patient was, on average, FIM 7358,
ranging from FIM 1299 to FIM 24751. The strongest explanatory factor for the
average total costs of orthodontic clinics was the number of general dentists
with little experience in providing orthodontic treatment. Other explanatory
factors were the number of orthodontists or experienced dentists, the percentage
of orthodontic tasks performed by auxiliary personnel, and the timing of
treatment. Savings might be obtained by devolving treatment to orthodontists or
experienced dentists instead of to dentists with little orthodontic experience,
and by starting treatment early. The estimated optimal size for an orthodontic
clinic was found to be a unit with 830 completely treated patients per year, but
most of the orthodontic clinics were in fact much smaller with, on average, 133
completely treated patients per year.
PMID- 9758428
TI - Evaluation of a dental benefit plan for children conducted in Auvergne, France,
since 1992.
AB - Usually, the French dental insurance system covers the cost of restorative
treatment but does not reimburse the cost of preventive therapies. A French sick
fund covering self-employed persons tested a new dental benefit plan for children
intended to provide an incentive to develop office-based preventive activities.
The programme, which started in 1992, concerns all 4-year-old children of self
employed workers in a single French region (Auvergne). Participants undergo an
annual examination by the dentist of their choice until their 15th birthday. If
the child is seen every year, all services related to dental caries (preventive
and restorative) are provided free of charge. An ongoing evaluation of the
programme was necessary to determine its influence on the development of office
based preventive activities and the dental health of the participants. A cohort
of children enrolled in the programme in 1992 was followed over 4 years to
examine the patterns of service use. In addition, a cross-sectional study
comparing the caries experience of all 8-year-old children participating
continuously in the programme (test sample) with that of a sample of control
children (n=90) was conducted in 1996. Data from the longitudinal follow-up
indicate that 43.37% of the 551 children to whom the programme was offered in
1992 underwent an annual examination in the first year. Of the children enrolled
in 1992, 55.2% were still participating in the programme in 1996. Results showed
that independent practitioners continued to focus on restorative treatment rather
than preventive therapy. Results from the cross-sectional study are in accordance
with this trend. The number of caries-free children was identical in test and
control samples and the mean dft, DMFT, DT and dt did not vary between the two
groups (Student's t-test, P>0.05). However the mean number of filled teeth was
significantly higher in the test children than in the controls (P<0.01). For
children with caries, the mean dft was 23.5% greater in the test group than in
the control group (P<0.05). In Auvergne, a large number of families were not
ready to participate in a plan that required them to take their child to the
dentist every year. There was not a perceived need for regular preventive dental
care, an attitude probably reinforced by the interventionist approach undertaken
by the dentists over the survey period. Moreover, the plan did not provide an
incentive for dentists to develop office-based preventive activities.
PMID- 9758430
TI - Mitochondrial regulation of mineralocorticoid biosynthesis by calcium and the
StAR protein.
PMID- 9758431
TI - Delayed puberty and peak bone mass.
PMID- 9758432
TI - Transcriptional repression: lessons from thyroid hormone action and promyelocytic
leukaemia.
PMID- 9758433
TI - Insulin receptor substrate-2--a new candidate gene for NIDDM?
PMID- 9758434
TI - A biological function for glucagon-like peptide-2.
PMID- 9758435
TI - Bone mineral status in prepubertal children with constitutional delay of growth
and puberty.
AB - OBJECTIVE: We wished to clarify whether the osteopenia reported in adult men with
a history of constitutional delay of growth and puberty (CDGP) could be due to
the delayed puberty or an independent predisposition to osteoporosis in this
condition. DESIGN: Short prepubertal children with CDGP and children with
familial short stature (FSS) were matched for height and other auxological
variables. The FSS children served as a control group. METHODS: We measured
spinal (L1-L4) bone mineral content (BMC) and bone mineral density (BMD) by dual
energy X-ray absorptiometry (Hologic QDR 1000/w) in 56 children aged 5-11 years.
All children had height below the 10th percentile for chronological age (CA), and
bone age (BA) less than 10 years, 29 of them with clinical diagnosis of possible
CDGP and 27 of them with FSS. The BMD standard deviation scores (SDS) relative to
the values for normal height children were obtained. RESULTS: The mean (+/-S.D.)
spinal BMD was significantly lower in the children with CDGP than in the FSS
group (0.534+/-0.059 vs 0.623+/-0.060 g/cm2, P< 0.001). Both groups had negative
mean lumbar BMD SDS, but in the CDGP group it was significantly lower than in the
FSS group as well when the SDS was based on the CA (-1.41+/-0.61 vs -0.38+/-0.51,
P< 0.001) and when it was related to BA (-0.78+/-0.64 vs -0.17+/-0.52, P< 0.01).
BMC was significantly lower in the CDGP than in the FSS group, when multiple
regression analysis was performed by using scanned bone area, body weight and
height, sex and BA as independent variables (P = 0.0005). CONCLUSION: The finding
of decreased mineralization in prepubertal children with CDGP before the age of
puberty suggests that they may have an inherent predisposition to osteopenia.
PMID- 9758436
TI - The importance of body weight history in the occurrence and recovery of
osteoporosis in patients with anorexia nervosa: evaluation by dual X-ray
absorptiometry and bone metabolic markers.
AB - In order to investigate the risk factors, pathogenesis and natural course of the
osteoporosis frequently seen in anorexia nervosa, we measured the bone mineral
density (BMD) of the lumbar spine using dual X-ray absorptiometry in 51 Japanese
female patients with anorexia nervosa, and followed the change in BMD of 29
patients for 11 to 46 months. We also evaluated the serum osteocalcin and the
urinary CrossLaps, degradation products of collagen I, in 103 samples obtained
from 51 patients. There was a significant correlation between the spinal BMD and
the duration of emaciation below a body mass index (BMI) of 15kg/m2 (r= -0.652,
P<0.0001) and 16kg/m2 (r= -0.647, P<0.0001). The increase in BMD per year in the
29 patients significantly correlated with the BMI at the time of entry of each
follow-up period (r= 0. 712, P<0.0001). The critical BMI for a positive increase
in BMD was 16.4+/-0.3 kg/m2 (mean+/-S.E.M.). The serum osteocalcin declined,
while the urinary CrossLaps increased in proportion to a decrease in BMI. Both
markers were normalized in patients whose BMI was between 16.4 and 18.5 kg/m2.
The ratio of urinary CrossLaps to serum osteocalcin correlated with BMI (r=
0.664, P<0.0001). We conclude that the body weight history is the most important
predictor of the presence of osteoporosis as well as of recovery The BMD of
patients does not increase to the normal range even several years after the
recovery from this disorder, and they remain a high-risk group for osteoporosis
in the future.
PMID- 9758437
TI - Management of hypoparathyroidism during pregnancy--report of twelve cases.
AB - There is no established therapeutic regimen for treatment of hypoparathyroidism
during pregnancy. This is due particularly to uncertainty about the use of
vitamin D or its analogues, as in animal experiments teratogenic side-effects
have been reported. Nevertheless, vitamin D or its analogues are required to
control tetany predisposing to abortion and preterm labour. We herein report the
course of two pregnancies in a hypoparathyroid woman treated with calcitriol
(1,25(OH)2D3). Additionally, we describe the outcome of pregnancy in ten women
receiving calcitriol, reported to the Drug Safety Department (DSD), Hoffmann-La
Roche AG. A 29-year-old hypoparathyroid woman receiving chronic treatment with
calcitriol (0.25 microg/day) and calcium (1.5 g/day) was referred in the 6th week
of her first pregnancy. Calcitriol was initially discontinued, but during the
20th week of pregnancy recurrent tetany occurred (serum calcium 1.74 mmol/l).
Calcitriol (0.25 microg/day) was added, stabilizing serum calcium around 2.15
mmol/l with 1,25(OH)2D3 concentrations around 60 ng/l (normal range 35-80 ng/l).
To maintain normocalcaemia the calcitriol dose was increased to 0.5 microg/day
during the 33rd week and to 0.75 microg/day shortly before delivery of a healthy
girl in the 3 7th week. During her second pregnancy calcitriol was given
initially at a dose of 0.25 microg/day with further adaptation to 0.5 microg/day
during the 20th and to 1.00 microg/day in the 31st week. Serum calcium and
1,25(OH)2D3 were continually within the lower normal range. She gave birth to
another healthy girl during the 39th week. In eight of the ten pregnancies
reported to the DSD no adverse effects of calcitriol (0.25-3.25 microg/day) were
seen and healthy babies were delivered. In two retrospectively reported cases,
serious adverse events were described: premature closure of the frontal
fontanelle, and stillbirth in the 20th week due to complex fetal malformation
respectively. However, in both cases the causative role of calcitriol
administration remains highly questionable. We conclude that, during pregnancy,
management of maternal hypoparathyroidism with calcitriol and calcium is
feasible, if the 1,25(OH)2D3 concentrations are adapted to the physiological
needs during pregnancy and serum calcium levels are kept in the lower normal
range.
PMID- 9758438
TI - Iodide induces thyroid autoimmunity in patients with endemic goitre: a
randomised, double-blind, placebo-controlled trial.
AB - OBJECTIVE: Iodine is essential for normal thyroid function and the majority of
individuals tolerate a wide range of dietary levels. However, a subset of
individuals, on exposure to iodine, develop thyroid dysfunction. In this double
blind trial, we evaluated the efficacy and tolerability of low-dose iodine
compared with those of levo-thyroxine (T4) in patients with endemic goitre.
METHODS: Sixty-two patients were assigned randomly to groups to receive iodine
(0.5 mg/day) or T4 (0.125 mg/day) for 6 months. Subsequently, both groups were
subject to placebo for another 6 months. Thyroid sonography, determination of
thyroid-related hormones and antibodies, and urinary excretion of iodine were
carried out at baseline and at 1, 6 and 12 months. RESULTS: At 6 months, markedly
increased urinary values of iodine were found in patients receiving iodine (36
microg/24 h at baseline, 415 microg/24 h at 6 months) compared with those
receiving T4 (47 microg/ 24 h at baseline, 165 microg/24 h at 6 months; P <
0.0001 compared with iodine group). T4 administration engendered a greater (P <
0.01) decrease in thyroid volume (from 32 ml to 17 ml, P < 0.0001) than did
intake of iodine (3 3 ml to 21 ml. P < 0.005). High microsomal and thyroglobulin
autoantibody titres were present in six of 31 patients (19%) receiving iodine,
and iodine-induced hypo- and hyperthyroidism developed in four and two of them,
respectively. Fine-needle biopsy revealed marked lymphocyte infiltration in all
six. After withdrawal of iodine thyroid dysfunction remitted spontaneously and
antibody titres and lymphocyte infiltration decreased markedly. Follow-up of
these six patients for an additional 3 years showed normalisation of antibody
titres in four of them. CONCLUSION: Although nearly comparable results were
obtained with both treatment regimens regarding thyroid size, partly reversible
iodine-induced thyroid dysfunction and autoimmunity were observed among patients
with endemic goitre.
PMID- 9758439
TI - Pulsatile GnRH or human chorionic gonadotropin/human menopausal gonadotropin as
effective treatment for men with hypogonadotropic hypogonadism: a review of 42
cases.
AB - Stimulatory therapy with either GnRH or gonadotropins is an effective treatment
to induce spermatogenesis and achieve paternity in men with secondary
hypogonadism. However, there is still uncertainty about the optimal treatment
modality and schedule, the duration of treatment necessary and the influence of
interfering factors such as maldescended testes. We have extended our previous
series of men treated for secondary hypogonadism and now present our therapeutic
experience with 42 cases. Twenty-one patients with hypothalamic disorders (11
with idiopathic hypogonadotropic hypogonadism (IHH) and 10 with Kallmann syndrome
(KalS)) were treated with GnRH (group Ia) or human chorionic gonadotropin
(hCG)/human menopausal gonadotropin (hMG) (group Ib), and 21 patients with
hypopituitarism (group II) were treated with hCG/hMG. A total of 5 7 treatment
courses were initiated for induction of spermatogenesis, 36 of these for the
purpose of induction of pregnancy in the female partner. Bilateral testicular
volumes doubled within 5-12 months of therapy. Spermatogenesis as evidenced by
the appearance of sperm in the ejaculate was induced in 54/57 courses.
Pregnancies occurred in 26/36 courses. Unilaterally maldescended testes did not
preclude patients with IHH or KalS from gaining fertility under therapy and
spermatogenesis could be successfully initiated even in some individuals with
bilateral maldescended testes. In general there was a tendency for a longer
duration of therapy until induction of spermatogenesis in patients with a history
of bilateral cryptorchidism. However, this did not reach statistical
significance. In patients with IHH or KalS treated with either hCG/hMG or GnRH
there were no statistically significant differences in terms of duration to
appearance of sperm or pregnancy rates. Even in KalS patients as old as 43 years
spermatogenesis could be induced. In repeatedly treated patients stimulation of
spermatogenesis tended to be faster while time until induction of pregnancy was
significantly shorter in the second treatment course. In conclusion, GnRH or
hCG/hMG are effective therapeutic modalities for patients with IHH or KalS. It
remains to be determined whether highly purified urinary gonadotropin
preparations or recombinant LH and FSH will provide therapeutic advantages.
PMID- 9758440
TI - High serum luteinizing hormone levels induce ovarian delta4 cytochrome
P450c17alpha down-regulation in hirsute women: complete effect on 17-hydroxylase
and partial effect on 17,20-lyase.
AB - It is well known that normal and mildly elevated luteinizing hormone (LH) levels
induce increased activity of ovarian 17-hydroxylase and 17,20-lyase, the
cytochrome P450cl7alpha (P450) enzymes. This leads to increased ovarian 17alpha
hydroxyprogesterone (17-OHP) and androstenedione production. In contrast, it has
been shown in both in vitro and in vivo studies in animals and in in vitro
studies in women that high LH concentrations have opposite effects on these
enzymes. These LH down-regulating effects appear to be more marked on 17,20-lyase
than on 17-hydroxylase. Finally, these LH effects have not been reported in vivo
in women. Therefore, we investigated the relationships between serum LH levels
and serum 17-OHP and androstenedione concentrations in 263 consecutive hirsute
women (HW) with normal serum 17-OHP responses to acute adrenocorticotropin (ACTH)
stimulation. The patterns of basal serum steroid concentrations differed
according to the basal serum LH levels. Indeed, for relationships between LH and
17-OHP concentrations, a positive correlation (P < 0.001) was found between the
levels of these parameters when LH levels ranged from 0.2 to 9.0 IU/l.
Conversely, for LH levels greater than 9.0 to 21.0 IU/l, LH values were
negatively correlated (P<0.001) with 17-OHP concentrations. Similar results were
observed for relationships between LH and androstenedione levels but the LH peak
level related to decreasing androstenedione concentrations was 12.0 IU/l.
Finally, the mean 17-OHP level in patients with LH levels which induced marked
P450 down-regulation (i.e. more than 12 IU/l) was similar to that in patients
with LH levels within the normal range (i.e. less than 6 IU/l). In contrast, the
mean androstenedione level in the former patients was markedly higher (P<0.001)
than that in the latter patients. In conclusion, as previously reported in in
vitro studies, this in vivo study indicates that LH induces stimulating and down
regulating effects on both ovarian delta(4)17-hydroxylase and delta(4)17,20-lyase
activities as serum LH levels gradually increase. However, in contrast to in
vitro studies, LH levels which induce P450 down-regulation appear to be less
effective on delta(4)17,20-lyase than on delta(4)17-hydroxylase in HW. This
strongly suggests that serum factors induce, in most HW, a marked increase in
delta(4)17,20-lyase, but not in delta(4)17-hydroxylase, activity leading to both
partial impairment of LH-induced delta(4)17,20-lyase down-regulation and complete
LH-induced delta(4)17-hydroxylase down-regulation in these patients.
PMID- 9758442
TI - Serial analysis of the effects of methimazole or radical therapy on circulating
CD16/56 subpopulations in Graves' disease.
AB - The distribution of peripheral blood CD16/56 cytotoxic T and natural killer (NK)
cells in Graves' disease patients is analyzed in order to correlate them with
disease activity and with prognosis. Eighteen patients with Graves' disease,
twenty-four patients with Hashimoto's thyroiditis and thirty-two sex- and age
matched healthy control subjects were studied. Peripheral blood CD16/56
(cytotoxic T and NK) cells were analyzed by cytofluorometry. A decreased
proportion of CD16/56+ and CD16/ 56+CD3+ cells were detected in Graves' disease
patients when compared with thyroiditis patients and healthy control groups. No
correlation was detected with serum free thyroxine. On diagnosis, patients who
would require a radical treatment for thyrotoxicosis control showed a significant
decrease of cytotoxic CD56+ T (CD3+) and NK (CD3-) cells compared with those who
would maintain the euthyroid state after methimazole. These results suggest that
the cytotoxic compartment, both T and NK cells, of the immune system is altered
in patients with Graves' disease, independently of the functional thyroid status.
Changes in peripheral blood lymphocytes in Graves' disease patients could be
useful as predictive markers of an unfavorable outcome.
PMID- 9758443
TI - Study of serum big-insulin-like growth factor (IGF)-II and IGF binding proteins
in two patients with extrapancreatic tumor hypoglycemia, using a combination of
Western blotting methods.
AB - Extrapancreatic tumor hypoglycemia (EPTH) is associated with increased amounts of
high-molecular-weight precursor forms of insulin-like growth factor (IGF)-II
('big-IGF-II') that have a primary role in the pathophysiology of hypoglycemia.
In the present study, using Western ligand and immunoblotting methods, we
investigated IGF-binding proteins (IGFBPs), IGFBP-3 proteolysis and big-IGF-II in
pre- and postoperative serum from two patients with EPTH due to benign pleural
fibroma. In the preoperative serum, IGFBP-3 was reduced and IGFBP-2 was increased
compared with that from an age-matched healthy control. IGFBP-3 proteolysis was
dramatically reduced in one patient, whereas no major alteration was observed in
the other (9% and 120% of control serum, respectively). IGFBPs progressively
returned to a subnormal pattern in postoperative serum, whereas IGFBP- 3
proteolysis remained greater than in preoperative serum in both patients at days
14 and 90 after surgery. High-molecular-weight forms of IGF-II predominate in
EPTH serum (65% and 57% of total IGF-II immunoreactivity in patients 1 and 2,
respectively, compared with 2 5% in control serum). Two forms, of molecular mass
10 and 12 kDa ('standard big-IGF-II') were present in both EPTH and control sera,
whereas two additional forms, of molecular mass 15 and 18 kDa ('big big-IGF-II')
were observed in EPTH sera only. Big big-IGF-II represented 72% and 55% of total
high-molecular-weight forms of IGF-II in the two EPTH sera, respectively. All big
forms of IGF-II disappeared from the serum as early as 6 h after surgery. This
study shows that combination of simple Western blotting methods, available
routinely in most laboratories, should prove useful in providing reliable
physiopathological information in EPTH.
PMID- 9758441
TI - Effect of acute and chronic administration of tamoxifen on GH response to GHRH
and on IGF-I serum levels in women with breast cancer.
AB - Tamoxifen, an estrogen antagonist, is usually employed in the treatment of breast
cancer. Its mechanism of action is not well known because an antiproliferative
effect of the drug has been shown also in estrogen receptor negative tumors, most
likely mediated by the inhibition of local growth factors and particularly IGF-I.
However, the action of tamoxifen on the GH-IGF-I axis is still open to
investigation. We have investigated the influence of acute and chronic treatment
with tamoxifen on GH response to GHRH and IGF-I serum levels in six
postmenopausal women with metastatic breast cancer. A GHRH test (50 microg i.v.
at time 0, GH determinations at 0, 15, 30, 60, 90 and 120 min) was performed (a)
basally, (b) 3 h after 40 mg oral administration of tamoxifen and (c) after 8
weeks of 20 mg twice a day oral tamoxifen treatment. IGF-I was measured basally
and after chronic tamoxifen therapy. No significant modifications in GH response
to GHRH were observed after acute or chronic treatment with tamoxifen vs the
basal test. On the contrary, chronic tamoxifen treatment induced a significant
decrease in serum IGF-I levels. Basal pretreatment levels of 123+/-18 microg/l
were suppressed to 65+/-11 microg/l (mean suppression 47%, P < 0.001). These
preliminary data confirm the inhibitory effect of tamoxifen on IGF-I production
but seem to exclude the possibility that this effect may be due to an inhibition
of GH secretion.
PMID- 9758444
TI - Utility of measuring serum parathyroid hormone-related protein concentration in
leukemic patients with hypercalcemia for assessing disease status.
AB - OBJECTIVE: To evaluate serum parathyroid hormone-related protein (PTHrP) as a
marker of hypercalcemia in leukemic patients. DESIGN AND METHODS: We measured the
serum levels of PTHrP, lactate dehydrogenase (LDH) and calcium in three patients
with hypercalcemia due to leukemia. RESULTS: Serum levels of PTHrP, LDH and
calcium were elevated at admission in all patients, and these levels were reduced
to within the normal range after chemotherapy. However, normalization of serum
PTHrP concentration occurred more rapidly than normalization of serum LDH levels
after chemotherapy. The increase in serum PTHrP concentration accompanied
leukemic cell proliferation and preceded the increases in serum LDH and calcium.
Serum LDH concentration increased, but serum PTHrP concentration did not after
administration of granulocyte colony-stimulating factor. CONCLUSION: These
findings suggest that serum PTHrP may be a more useful marker than serum LDH or
calcium in assessing the status of leukemic patients with hypercalcemia.
PMID- 9758446
TI - Prolactin secretion and its dopamine inhibitory control in rat fetuses.
AB - This study has determined in rats the ontogenetic schedule of the onset of
pituitary prolactin (PRL) synthesis and release as well as of the establishment
of the dopamine (DA) inhibitory control of PRL secretion. RIA recognized PRL
traces in the pituitary at the 18th embryonic day (E18), although a clearly
detectable amount of this hormone was first measured at E20, suggesting the onset
of PRL synthesis. The PRL level in the pituitary increased significantly by E22,
in females to a higher extent than in males. Decapitation of fetuses did not
cause any change in the PRL plasma level in males showing no PRL release from the
pituitary until term. Conversely, there was a slight but significant fall of
plasma PRL in decapitated females, suggesting PRL release from the pituitary. An
inhibition of DA receptors on lactotropes of fetuses resulted in an increased
level of plasma PRL at E20, but not at E18, while the pituitary content of PRL
remained unchanged. The same treatment at E22 caused a significant increase of
the PRL concentration in plasma and a concomitant fall in the pituitary that
could be prevented by preliminary encephalectomy. These data show that the
tuberoinfundibular DA system begins to inhibit PRL release from lactotropes
between E20 and E22, completely arresting PRL release from the pituitary in males
but not in females.
PMID- 9758445
TI - A novel missense (R80W) mutation in 17-beta-hydroxysteroid dehydrogenase type 3
gene associated with male pseudohermaphroditism.
AB - OBJECTIVE: Deficit of the testosterone converting enzyme 17-beta-hydroxysteroid
dehydrogenase (17beta-HSD) has been shown to be responsible for male
pseudohermaphroditism (MPH). We analysed the gene encoding 17beta-HSD type 3
(17beta-HSD3) in a patient with MPH. METHODS: We studied a 46, XY new-born
diagnosed as having MPH. The child also had other congenital disorders, including
a giant omphalocele and Fallot's tetralogy, and died of post-surgical
complications at age 4.5 months. Basal hormonal levels, and after human chorionic
gonadotrophin stimulation, suggested a deficiency in 17beta-HSD as the
biochemical defect underlying this MPH. PCR amplification and subsequent
sequencing of all coding exons of the 17beta-HSD3 gene were performed on genomic
DNA from the patient and both parents. Messenger RNA was extracted from the
patient's testis and 17beta-HSD3 cDNA was synthesized, PCR amplified and
sequenced. RESULTS: Sequencing revealed the presence of a homozygous missense
mutation (R80W) in exon 3 of the 17beta-HSD3 gene, which was also present in
single doses in both parents, in accordance with the recessive inheritance of the
defect. No other mutation was found, and cDNA sequencing confirmed correct
synthesis and processing of 17beta-HSD3 mRNA. CONCLUSIONS: Confirming the
abnormal delta4-androstenedione/testosterone ratios that suggested 17beta-HSD
deficiency, a homozygous missense mutation in the gene coding for this enzyme was
identified in the patient with MPH. This study adds further genetic evidence to
the role of 17beta-HSD3 in male sexual development. There is no evidence
supporting the association of this mutation in 17beta-HSD3 with the congenital
malformations other than MPH present in the child.
PMID- 9758447
TI - Growth hormone-releasing hexapeptide (GHRP-6) increases intracellular calcium
concentrations in cultured cells from human pituitary adenomas of different
types.
AB - OBJECTIVE: The GH-releasing peptide GHRP-6, has been found to interact with
specific receptors in somatotrophs, causing cytosolic Ca2+ ([Ca2+]i) rise and GH
release. Moreover, this peptide has been demonstrated to stimulate the secretion
of pituitary hormones other than GH, i.e. ACTH and prolactin, this effect being
generally attributed to a central action. In this study we evaluated whether the
pituitary action of this peptide is restricted to cell type of somatotroph
lineage. METHODS: The effect opf GHRP-6 on [Ca2+]i was tested in cell
preparations obtained from a series of human pituitary adenomas (9 GH-secreting
adenomas, 7 nonfunctioning adenomas, 3 ACTH-secreting adenomas, 2 TSH-secreting
adenomas and 1 prolactinoma) loaded with the Ca2+ indicator fura-2. RESULTS: GHRP
6, at concentrations higher than 1 nmol/l, significantly increased [Ca2+]i in all
tumours, with the exception of the 3 ACTH-secreting adenomas in which the peptide
was ineffective at any concentration tested (from 1 nmol/l to 1 micromol/l). By
contrast, in all ACTH-secreting adenomas, both corticotrophin-releasing hormone
and pituitary adenylate cyclase activating peptide caused a marked [Ca2+]i
increase. In tumours responsive to GHRP-6, the peptide caused a typical biphasic
[Ca2+]i rise due to Ca2+ mobilization from the intracellular stores and Ca2+
influx through voltage-dependent Ca2+ channels. CONCLUSIONS: These data indicate
that almost all tumoral pituitary cell types are targets of GHRP-6 action, the
only exception being corticotrophs.
PMID- 9758448
TI - The expression of the beta 1 integrin CD29 and the beta 2 integrin CD11b is
decreased in peripheral blood lymphocytes from Graves' disease patients.
AB - We have prospectively examined the percentage of peripheral blood lymphocytes
which expressed adhesion molecules in untreated Graves' disease patients.
Eighteen patients with Graves' disease, twenty-four patients with Hashimoto's
thyroiditis and thirty-two sex- and age-matched healthy control subjects were
studied. The expression of the lymphocyte adhesion molecules beta-1 integrin
CD29, beta-2 integrin CD11b and L-selectin Leu8 (CD62L) was analyzed by
cytofluorometry. A decreased percentage of CD29+ and CD11b+ lymphocytes was
observed in hyperthyroid patients in comparison with Hashimoto's thyroiditis
patients and healthy controls. However, there was no difference in the percentage
of CD62L+ lymphocytes in the three groups. Percentages of lymphocyte activation
markers, hyperthyroid status, presence or absence of ophthalmopathy or serum
levels of antithyroid antibodies were not related to the proportions of CD29+ or
CD11b+ lymphocytes. Four Graves' patients required radical therapy but after the
treatment, there was no modification in the percentages of CD29+ and CD11b+
lymphocytes compared with those determined at diagnosis. Our findings suggest
that the decrease in beta-1 and beta-2 integrins could be a predisposing marker
of development of Graves' disease.
PMID- 9758450
TI - When to refer.
PMID- 9758449
TI - Heterogeneous signal pathways through TSH receptors in porcine thyroid cells
following stimulation with Graves' immunoglobulin G.
AB - OBJECTIVE: We compared different signal transduction pathways through thyroid
stimulating hormone receptor (TSH-R) in porcine thyroid cells (PTC) following
stimulation with thyroid stimulating hormone (TSH) and 11 thyroid stimulating
immunoglobulin samples (TSI) obtained from patients with Graves' disease. DESIGN:
Following stimulation with TSI, the level of inositol trisphosphate (IP3) and
[Ca2+]i, as well as the membrane bound protein kinase C (PKC) activity and the
intensity of the arachidonic acid (AA) cascade, were determined in PTC. RESULTS:
Seven out of eleven TSI samples activated PTC through IP3 generation, elevated
[Ca2+]i from the intracellular pools, exhibited verapamil-insensitive membrane
bound PKC activation, and enhanced release of [14C]AA derivates (however, one of
the samples was also able to take up Ca2+ from the extracellular space). Four out
of eleven TSI samples did not activate the phospholipase C (PLC) system in which
case the Ca2+ signal occurred only in the presence of extracellular Ca2+, the
membrane bound PKC activation was verapamil sensitive, and in two of these four
TSI samples, the AA release was extremely high. CONCLUSIONS: The simultaneous
examination of the majority of the known signal pathways using TSI samples showed
that TSI samples from different patients activate thyroid cells through different
pathways. Their effects differ from that of TSH and, to a certain extent, from
each other. The results give a certain new insight into the intracellular
mechanisms exerted by TSI.
PMID- 9758451
TI - The pediatric Monteggia fracture.
AB - Since Monteggia first described the fracture bearing his name in 1814, the
association of radial head dislocation with ipsilateral ulnar fracture has been
well described. Monteggia fractures and their variants are often misdiagnosed,
however, because of the numerous atypical presentations of this injury in
children. This article describes the diagnosis, treatment, and potential pitfalls
encountered in the treatment of Monteggia fractures.
PMID- 9758452
TI - Clinical evaluation of the Alta hip bolt in peritrochanteric hip fractures.
AB - We reviewed the clinical and radiographic results of 58 patients with
peritrochanteric fractures treated with the Alta hip bolt (a sliding compression
device that inserts a dome plunger in the femoral head instead of a hip screw).
This group was compared with a group of 53 patients treated with conventional hip
screws. Three patients (5.2%) treated with the Alta hip bolt and three patients
(5.7%) treated with conventional hip screw had failure of fixation. Failure of
fixation consistently occurred in patients with unstable fracture patterns or
significant osteopenia. There were no cases of bolt cut-out in stable
intertrochanteric fractures. We conclude that the Alta hip bolt performs as well
as sliding hip screws in peritrochanteric fractures, but the additional learning
curve and increased cost do not justify its routine use at this point in time.
PMID- 9758453
TI - Use of an internal fixator device to treat comminuted fractures of the distal
radius: report of a technique.
AB - An internal fixator technique for stabilizing comminuted Colles fractures has
been developed in the anatomy laboratory and used in 35 clinical cases. The
Colles Fracture Plate (Biomet, Inc, Warsaw, Indiana) can be used to treat any
comminuted Colles fracture for which an external fixator is considered proper
management. We have determined, based on our surgical experience with both the
internal and external fixator techniques, that internal fixation using the Colles
Fracture Plate is technically just as simple as external fixation. In addition to
requiring a significantly less expensive device, internal fixation using this
technique offers the advantages of better patient acceptance and fewer
complications. This report will be followed by a more comprehensive analysis of
the technical outcome of this procedure to further substantiate the initial
results presented here. The process of compiling and analyzing these data is
under way.
PMID- 9758455
TI - Fracture of the proximal tibia after anterior cruciate ligament reconstruction: a
case report.
AB - A case of fracture of the proximal tibia at the site of graft harvest for an
anterior cruciate ligament reconstruction is reported. This fracture, at the
distal edge of the harvest site on the tibial tubercle, was the result of stress
concentration at this location. The patient's tibia fracture was treated with a
long leg cast and healed without complication. Fracture of the patella at the
graft harvest site has been reported as a complication of anterior cruciate
ligament reconstruction. This is the first report of a fracture of the tibia at
the site of graft harvest.
PMID- 9758454
TI - Femoral osteomyelitis after tooth extraction.
AB - Up to 35% of normal individuals may harbor Hemophilus aphrophilus in their
oropharynx. Generally, this organism is well tolerated and rarely causes systemic
infections; however, osteomyelitis may occur and it has previously been described
involving the spine. Because of an intrinsic ability to inhibit leukocytes,
osseous infections from this organism characteristically present in an insidious
fashion. A case of severe femoral osteomyelitis after dental extraction is
described.
PMID- 9758456
TI - Problems of various fixation methods for open tibia fractures: experience in a
Japanese level I trauma center.
AB - Two hundred thirty-seven patients with open tibial fractures (245 fractures) were
treated as follows: nonoperative stabilization alone (Nonop group, n = 54);
immediate open reduction and internal fixation (ORIF group, n = 47); delayed ORIF
(D-ORIF group, n = 109); or external fixation (EF group, n = 35). The D-ORIF
group was further divided into ORIF after nonoperative treatment (Nonop/ORIF, n =
86), and ORIF after external fixation (EF/ORIF, n = 23). The open tibial
fractures were classified as follows: 42 type I (no infections), 107 type II (4
infections), 43 type IIIA (3 infections), 42 type IIIB (12 infections), and 11
type IIIC (2 infections), with significant differences in infection rate between
type IIIB and type I, type II, or type IIIA. The deep infection rates in Nonop,
ORIF, Nonop/ORIF, EF/ORIF, and EF groups were 3.7%, 12.8%, 5.8%, 30.4%, and 2.9%,
respectively. There were significant differences in deep infection rates between
the EF/ORIF and Nonop/ORIF, and the EF group. The mean period of fracture healing
for type IIIB fractures was delayed. The mean time to union of the EF/ORIF was
significantly longer than that of the ORIF, Nonop/ORIF, and EF groups,
respectively. Complete and consecutive debridement procedures and early soft
tissue coverage should be done to avoid wound infection, especially in type IIIB
fractures. Delayed internal fixation after external fixation had the highest risk
of infection, mandating meticulous wound management in such patients.
PMID- 9758457
TI - Proximal locking screw repositioning in reconstruction femoral nails.
AB - The proximal locking screws in reconstruction femoral nailing must be inserted
properly. A targeting device that is not completely radiolucent can make precise
positioning of these screws in the lateral plane difficult. We present a
technique that we have used in osteoporotic bone to reposition screws that are
not in the center of the femoral head on the lateral C-arm view.
PMID- 9758459
TI - Manometric study of the effects of experimental fundoplication in rats.
AB - BACKGROUND: The manometric effects of surgical repair of gastroesophageal reflux
remain largely unknown, making the interpretation of the changes in the
esophagogastric high pressure zone after fundoplication difficult. AIM: To
measure in a murine model the transdiaphragmatic pressure gradients,
intraabdominal esophageal length, and lower esophageal sphincter pressure and
length after Nissen fundoplication. MATERIAL AND METHODS: Adult Wistar rats were
divided into two groups Control group (n = 10): in which measurements were made
after laparotomy and intraabdominal esophageal dissection. Nissen Group (n = 15):
in which measurements were made at baseline, after fundoplication and 1 week
after surgery. We considered the following variables: end-inspiratory and end
expiratory transdiaphragmatic gradient (TDIG and TDEG respectively), lower
esophageal sphincter pressure (LESP) length (LESL), and length of the
intraabdominal segment of the esophagus (LIAS). RESULTS: The LIAS increased
significantly after esophagogastric dissection in the control group (11.38 +/-
3.22 mm vs 16.02 +/- mm, p < 0.05). No differences between pre- and postoperative
status were found in TDIG, TDEG, LESP and LESL in the control group. However,
LESP increased significantly after fundoplication (14.22 +/- 13.3 vs 32.96 +/-
7.8 mmHg, p < 0.05) and these differences were still present one week later
(30.72 +/- 6.73 mmHg, p < 0.05). LESL was also increased (1.91 +/- 1.76 mm vs
7.68 +/- 1.83 mm) after fundoplication (p < 0.05), and reached 7.02 +/- 2.18 mm
(p < 0.05) 1 week later. No differences were found in pre- and postoperative
TDIG, TDEG and LIAS in the Nissen Group. CONCLUSION: In this murine experimental
model, intraabdominal esophageal dissection increased the length of the
intraabdominal esophagus without modifying the esophagogastric high pressure
zone, while Nissen fundoplication increased lower esophageal sphincter pressure
and length, without modifying the length of the intraabdominal esophagus or the
transdiaphragmatic pressure gradients.
PMID- 9758460
TI - Speech of the Health Minister to the BDA Conference 1998.
PMID- 9758458
TI - The areA(r) mutation of Aspergillus nidulans confers low pH sensitivity in the
presence of ammonium as the only nitrogen source.
AB - The utilization of nitrogen sources by the fungus Aspergillus nidulans is
controlled by a mechanism mediated by areA, a wide domain regulatory gene. It has
been verified that the strains carrying the mutant allele areAr are inhibited
when growing at low pH in the presence of ammonium as the only nitrogen source.
The genetic analysis of this marker showed that it apparently maps at the areA
locus.
PMID- 9758461
TI - Developmental genetics of Drosophila. Special issue dedicated to Antonio Garcia
Bellido.
PMID- 9758462
TI - [Management of contact cheilitis in primary care].
PMID- 9758463
TI - Peptide nucleic acid (PNA) from DNA recognition to antisense and DNA structure.
AB - The biophysical and biological properties of PNA (peptide nucleic acid) is
briefly reviewed with special emphasis on recent three dimensional structures of
PNA-nucleic acid complexes and on structure-activity relations in terms of
nucleic acid hybridization properties. 1997 Elsevier Science B.V.
PMID- 9758464
TI - Consultants' merit award system to be reformed.
PMID- 9758465
TI - Telephone advice scheme criticised.
PMID- 9758466
TI - Organophosphate pesticides are being tested on students.
PMID- 9758467
TI - China to expand rural healthcare system.
PMID- 9758468
TI - Heroin use among young people is increasing in England and Wales.
PMID- 9758469
TI - Should doctors perform an elective caesarean section on request? Maternal choice
alone should not determine method of delivery.
PMID- 9758470
TI - Risk of connective tissue disease among women with breast implants. Authors
should have made better use of matched control group.
PMID- 9758471
TI - Diagnosis of Creutzfeldt-Jakob disease by measurement of S100 protein in serum.
Tonsil biopsy helps diagnose new variant Creutzfeldt-Jakob disease.
PMID- 9758472
TI - Use of statins. But New Zealand tables are better.
PMID- 9758473
TI - Career options available to general practitioner assistants. Reply by chairman of
General Practitioners Committee's medical work force subcommittee.
PMID- 9758474
TI - Postnatal health education in Nepal. There are no shortcuts.
PMID- 9758475
TI - Postnatal health education in Nepal. Quality of health education was not measured
objectively.
PMID- 9758477
TI - Users of NHS will be surveyed.
PMID- 9758476
TI - Cardiac surgery inquiry given wide remit.
PMID- 9758478
TI - Quality of UK milk to be studied.
PMID- 9758479
TI - Two Scottish surgeons suspended.
PMID- 9758480
TI - Prognosis of symptoms that are medically unexplained. Clinical guidelines are
needed.
PMID- 9758481
TI - Prognosis of symptoms that are medically unexplained. Follow up study needs to be
continued for longer.
PMID- 9758482
TI - Prognosis of symptoms that are medically unexplained. Psychological aspects of
investigations must be addressed early.
PMID- 9758483
TI - Relation of rates of self referral to A&E departments to deprivation. Distance
from department and deprivation are both important in explaining variations in
rates.
PMID- 9758484
TI - Bereavement in adult life. Psychotropic drugs may be appropriate treatment.
PMID- 9758485
TI - Pressures in outpatient clinics. Increasing numbers of ward referrals are an
additional pressure.
PMID- 9758486
TI - Magnesium sulphate in pre-eclampsia. Still room for improvement.
PMID- 9758487
TI - Human fertilisation and Embryology Act 1990 discriminates against girls.
PMID- 9758488
TI - Carcinogen in tobacco smoke can be passed to fetus.
PMID- 9758489
TI - Tuberculosis controls in Philippines have failed so far.
PMID- 9758490
TI - Treating chronic fatigue with exercise. Exercise improves mood and sleep.
PMID- 9758491
TI - Treating chronic fatigue with exercise. Results are contradictory for patients
meeting different diagnostic criteria.
PMID- 9758492
TI - Hypoxic responses in infants. Research should contain element of treatment.
PMID- 9758493
TI - Hypoxic responses in infants. No known mechanism links hypoxia and sudden infant
death syndrome.
PMID- 9758494
TI - Hypoxic responses in infants. Danger to babies from air travel must be small.
PMID- 9758495
TI - Hypoxic responses in infants. Study methods need to be appropriate.
PMID- 9758496
TI - Hypoxic responses in infants. Public must be warned of weak evidence for risk of
serious harm.
PMID- 9758497
TI - Hypoxic responses in infants. Risks associated with hypoxia during flights need
to be investigated.
PMID- 9758498
TI - Helicobacter pylori and surgery. Helicobacter pylori is merely suppressed by
bile.
PMID- 9758499
TI - Helicobacter pylori and surgery. Role of bile reflux is insufficiently explained.
PMID- 9758500
TI - Helicobacter pylori and surgery. Authors should not extrapolate findings into
unresearched areas.
PMID- 9758501
TI - Screening for Chlamydia trachomatis. Contacts attendance rate is 70% in
Hertfordshire.
PMID- 9758502
TI - Screening for Chlamydia trachomatis. Genitourinary medicine clinics in Scotland
give high priority to contact tracing.
PMID- 9758503
TI - Screening for Chlamydia trachomatis. New technologies enable screening to be
carried out in schools and the community.
PMID- 9758504
TI - Screening for Chlamydia trachomatis. Screening for and treatment of chlamydial
infection demand commitment.
PMID- 9758505
TI - Central venous catheters and infection. Routine placement of central venous
catheters should be retained.
PMID- 9758506
TI - Central venous catheters and infection. Colonisation of lines does not cause
complications, but insertion does.
PMID- 9758507
TI - Central venous catheters and infection. Use of antimicrobial catheters needs to
undergo trials.
PMID- 9758508
TI - Consumers. Relative care.
PMID- 9758509
TI - Flow cytometric detection of proliferation-associated antigens, PCNA and Ki-67.
PMID- 9758510
TI - 1st International Congress on Endoscope-assisted Microneurosurgery. Abstracts.
PMID- 9758511
TI - [Niemann-Pick disease (type C)].
PMID- 9758513
TI - Nuclear cardiology in the literature.
PMID- 9758512
TI - Characterization of cyanogen bromide fragments of reduced human serum albumin by
matrix-assisted laser desorption/ionization mass spectrometry.
PMID- 9758514
TI - Must a physician be present for both a stress test and the imaging, or may this
be handled by technologist.
PMID- 9758515
TI - The Asian Women's Health Clinic: addressing cultural barriers to preventive
health care.
PMID- 9758516
TI - Private sector becoming the key to research funding in Canada.
AB - The private sector, and drug companies in particular, are beginning to play a
much stronger and visible role in funding health care research in canada. The
implications of this change were discussed at a recent conference.
PMID- 9758517
TI - Controlling health care costs a costly business for HMOs in US.
PMID- 9758518
TI - Proceedings of the 10th International Conference on Partitioning in Aqueous Two
Phase Systems. Reading, United Kingdom, 10-15 August 1997.
PMID- 9758519
TI - What's in a name.
PMID- 9758520
TI - What's in a name.
PMID- 9758521
TI - What are family planning clinics for.
PMID- 9758522
TI - What are family planning clinics for.
PMID- 9758523
TI - What are family planning clinics for.
PMID- 9758524
TI - How should induced abortion rates be measured.
PMID- 9758525
TI - What are family planning clinics for.
PMID- 9758526
TI - Pregnancy while using Norplant.
PMID- 9758527
TI - The view from Haringey.
PMID- 9758528
TI - Guidelines for pediatric equipment and supplies for basic and advanced life
support ambulances.
PMID- 9758530
TI - USAN Council. List No.407. New names. Lenercept.
PMID- 9758531
TI - USAN Council. List No.407. New names. Trafermin.
PMID- 9758529
TI - An abbreviated account.
PMID- 9758533
TI - Catecholamines and the cardiovascular system. Proceedings of a meeting. Sophia
Antipolis, France, 4-6 December 1997.
PMID- 9758532
TI - Proceedings of the Brenot Memorial Symposium on the Pathogenesis of Primary
Pulmonary Hypertension. Corisca, July 29-31, 1997.
PMID- 9758535
TI - Renin-angiotensin in preascitic cirrhosis: evidence for primary peripheral
arterial vasodilation.
PMID- 9758534
TI - Gut patterning: the case of the missing cecum.
PMID- 9758536
TI - Pancreatic stellate cells: the new stars of chronic pancreatitis?
PMID- 9758537
TI - Tolerance and sensitivity: ethanol and Kupffer cells.
PMID- 9758538
TI - Optical coherence tomography: lighting the way around optical biopsy.
PMID- 9758539
TI - In search of the cause of idiopathic intestinal pseudo-obstruction: is there a
viral etiology?
PMID- 9758540
TI - The energy to make acid.
PMID- 9758541
TI - Interferon alfa for chronic hepatitis C: how do we define cure?
PMID- 9758542
TI - Therapy for hepatorenal syndrome.
PMID- 9758543
TI - Cholic acid synthesis from 27-hydroxycholesterol in humans.
PMID- 9758544
TI - Gastrin sensitivity and acid in H. pylori: revisited.
PMID- 9758545
TI - Helicobacter pylori and acid secretion.
PMID- 9758546
TI - Resistant starch and SCFA: adjunct to ORS?
PMID- 9758547
TI - H. pylori eradication and gastric precancerous lesions.
PMID- 9758548
TI - Potential population-wide impact of aspirin on colon cancer mortality.
PMID- 9758549
TI - Swallowing and LES relaxation with reflux: not by chance.
PMID- 9758550
TI - Identification and mutation analysis of a cochlear-expressed, zinc finger protein
gene at the DFNB7/11 and dn hearing-loss loci on human chromosome 9q and mouse
chromosome 19.
AB - The DFNB7/11 locus for autosomal recessive non-syndromic hearing loss (ARNSHL)
has been mapped to an approx. 1.5 Mb interval on human chromosome 9q13-q21. We
have determined the cDNA sequence and genomic structure of a novel cochlear
expressed gene, ZNF216, that maps to the DFNB7/11 interval. The mouse orthologue
of this gene maps to the murine dn (deafness) locus on mouse chromosome 19. The
ZNF216 gene is highly conserved between human and mouse, and contains two regions
that show homology to the putative zinc linger domains of other proteins. To
determine it mutations in ZNF216 might be the cause of hearing loss at the
DFNB7/11 locus, we screened the coding region of this gene in DFNB7/11 families
by direct sequencing. No potential disease-causing mutations were found. In
addition, Northern blot analysis showed no difference in ZNF216 transcript size
or abundance between dn and control mice. These data Suggest that the ZNF216 gene
is unlikely to be responsible for hearing loss at the DFNB7/11 and dn loci.
PMID- 9758551
TI - Genotypically dependent effects of cyromazine on reproduction and offspring
development in the Australian Lucilia cuprina (Diptera: Calliphoridae).
AB - The effects of cyromazine on egg production and subsequent egg-to-adult survival
were examined on susceptible, heterozygous, and homozygous cyromazine-resistant
genotypes of the Australian sheep blowfly Lucilia cuprina (Wiedemann) by
administering to adults 10 ppm of cyromazine in drinking water. Cyromazine
reduced egg production, hatch, and subsequent larval survival in susceptible
genotypes by acting at the embryonic stage of development. Resistance negated
these effects dominantly for egg production and egg hatch and in a partially
dominant manner for egg-to-adult survivorship.
PMID- 9758552
TI - [Hepatocyte nuclear factor 6: a novel class of liver-enriched transcription
factor].
PMID- 9758553
TI - Thrombogenic and atherogenic lipid modifications in plasma and patients with
coronary artery disease and after coronary artery bypass surgery.
PMID- 9758554
TI - [Alzheimer disease. Pseudo-irreversible AChE inhibition with rivastigmine].
PMID- 9758555
TI - [Alzheimer disease. Irreversible AChE inhibition with metrifonate].
PMID- 9758556
TI - [Application of lymphoscintigraphy in post-mastectomy lymphedema of the upper
extremities].
PMID- 9758557
TI - [Participation of interleukin-6 to skeletal muscle proteolysis: the effect of IL
6 administration on mRNA expression by the skeletal muscle cell proteolytic
system].
PMID- 9758558
TI - [Trial determination of bile flow volume in the common bile duct by using a
transit time ultrasonic flowmeter--in relation to the contractile movement of the
duodenum].
PMID- 9758559
TI - [Effect of Lazaroid U-74389G on ischemic reperfusion injury of the lung].
PMID- 9758560
TI - Vestibular Adaptation. Proceedings of a conference. Santa Monica, California,
USA. May 23-25, 1996.
PMID- 9758561
TI - Bibliography of Neville Butler.
PMID- 9758562
TI - Human Rights and Dignity in the Practice of Medicine. Proceedings of an
International Medical Symposium. Copenhagen, Denmark, September 21-22, 1996.
PMID- 9758563
TI - Voorjaarsdagen Congress 1998. Amsterdam, April 24-26, 1998. Proceedings.
PMID- 9758564
TI - The animal as a companion; the characteristics of a symbiosis.
PMID- 9758565
TI - Vet faces monkey.
PMID- 9758566
TI - Marketing and management of practice services.
PMID- 9758567
TI - Competition or cooperation?
PMID- 9758568
TI - Febrile nonresponsiveness of vagotomized animals: is it due to endotoxin
translocation from the gut and tolerance?
PMID- 9758569
TI - Radiologists' review of radiographs.
PMID- 9758570
TI - Multivitamin use, folate, and colon cancer in women in the Nurses' Health Study.
AB - BACKGROUND: High intake of folate may reduce risk for colon cancer, but the
dosage and duration relations and the impact of dietary compared with
supplementary sources are not well understood. OBJECTIVE: To evaluate the
relation between folate intake and incidence of colon cancer. DESIGN: Prospective
cohort study. SETTING: 88,756 women from the Nurses' Health Study who were free
of cancer in 1980 and provided updated assessments of diet, including
multivitamin supplement use, from 1980 to 1994. PATIENTS: 442 women with new
cases of colon cancer. MEASUREMENTS: Multivariate relative risk (RR) and 95% CIs
for colon cancer in relation to energy-adjusted folate intake. RESULTS: Higher
energy-adjusted folate intake in 1980 was related to a lower risk for colon
cancer (RR, 0.69 [95% CI, 0.52 to 0.93] for intake > 400 microg/d compared with
intake < or = 200 microg/d) after controlling for age; family history of
colorectal cancer; aspirin use; smoking; body mass; physical activity; and
intakes of red meat, alcohol, methionine, and fiber. When intake of vitamins A,
C, D, and E and intake of calcium were also controlled for, results were similar.
Women who used multivitamins containing folic acid had no benefit with respect to
colon cancer after 4 years of use (RR, 1.02) and had only nonsignificant risk
reductions after 5 to 9 (RR, 0.83) or 10 to 14 years of use (RR, 0.80). After 15
years of use, however, risk was markedly lower (RR, 0.25 [CI, 0.13 to 0.51]),
representing 15 instead of 68 new cases of colon cancer per 10,000 women 55 to 69
years of age. Folate from dietary sources alone was related to a modest reduction
in risk for colon cancer, and the benefit of long-term multivitamin use was
present across all levels of dietary intakes. CONCLUSIONS: Long-term use of
multivitamins may substantially reduce risk for colon cancer. This effect may be
related to the folic acid contained in multivitamins.
PMID- 9758571
TI - Efficacy and tolerability of stavudine plus lamivudine in treatment-naive and
treatment-experienced patients with HIV-1 infection.
AB - BACKGROUND: A combination of two nucleoside analogues is currently the core of
any antiretroviral regimen for HIV-1 infection. Stavudine plus lamivudine has
shown an additive effect in vitro, as well as an absence of overlapping toxicity
and cross-resistance. OBJECTIVE: To evaluate the antiviral efficacy of stavudine
plus lamivudine in treatment-naive patients and in patients previously treated
with other nucleoside reverse transcriptase inhibitors. DESIGN: Prospective, open
label pilot study. SETTING: Three urban clinical centers in Paris. PATIENTS: 83
patients with CD4+ cell counts between 50 and 400 cells/mm3 (42 treatment-naive
and 41 treatment-experienced patients). INTERVENTIONS: Stavudine, 40 mg twice
daily (30 mg twice daily in patients with a body weight < or = 60 kg), and
lamivudine, 150 mg twice daily. MEASUREMENTS: Primary end points for efficacy
included changes in plasma viral load and CD4+ cell count at 24 weeks compared
with baseline. RESULTS: Therapy with stavudine plus lamivudine resulted in a
median decrease of 1.66 log10 (10(1.66)) (range, -3.04 to -0.79 log10) in plasma
HIV-1 RNA; the median increase in CD4+ cell count was 108 cells/mm3 (range, -58
to 406 cells/mm3) at week 24 in treatment-naive patients. In treatment
experienced patients, the median reduction in plasma HIV-1 RNA was 0.55 log10
(range, -2.86 to 0.52 log10), and the median increase in CD4+ cell count was 46
cells/mm3 (range, -188 to 311 cells/mm3). The percentages of patients with less
than 3000 HIV-1 RNA copies/mL and less than 400 copies/mL at 24 weeks were,
respectively, 57% (95% CI, 41% to 72%) and 26% (CI, 12% to 40%) among treatment
naive patients and 22% (CI, 10% to 38%) and 5% (CI, 1% to 17%) among treatment
experienced patients. Of 82 patients, 14 (17%) experienced grade 3 or 4 toxicity
and 2 discontinued therapy because of intolerance toward treatment. CONCLUSION:
Stavudine plus lamivudine seems to have a potent antiviral effect in treatment
naive and treatment-experienced patients. No major drug-limiting toxicity was
found. This two-nucleoside combination should be considered in multidrug therapy
for HIV.
PMID- 9758572
TI - Relation of family responsibilities and gender to the productivity and career
satisfaction of medical faculty.
AB - BACKGROUND: Studies have found that female faculty publish less, have slower
career progress, and generally have a more difficult time in academic careers
than male faculty. The relation of family (dependent) responsibilities to gender
and academic productivity is unclear. OBJECTIVE: To describe dependent
responsibilities by gender and to identify their relation to the aspirations,
goals, rate of progress, academic productivity, and career satisfaction of male
and female medical school faculty. DESIGN: 177-item survey questionnaire.
SETTING: 24 randomly selected medical schools in the contiguous United States.
PARTICIPANTS: 1979 respondents from a probability sample of full-time academic
medical school faculty. MEASUREMENTS: The main end point for measuring academic
productivity was the total number of publications in refereed journals. Perceived
career progress and career satisfaction were assessed by using Likert scales.
RESULTS: For both male and female faculty, more than 90% of time devoted to
family responsibilities was spent on child care. Among faculty with children,
women had greater obstacles to academic careers and less institutional support,
including research funding from their institutions (46% compared with 57%; P <
0.001) and secretarial support (0.68 full-time equivalents compared with 0.83
full-time equivalents; P = 0.003), than men. Compared with men with children,
women with children had fewer publications (18.3 compared with 29.3; P < 0.001),
slower self-perceived career progress (2.6 compared with 3.1; P < 0.001), and
lower career satisfaction (5.9 compared with 6.6; P < 0.001). However, no
significant differences between the sexes were seen for faculty without children.
CONCLUSIONS: Compared with female faculty without children and compared with men,
female faculty with children face major obstacles in academic careers. Some of
these obstacles can be easily modified (for example, by eliminating after-hours
meetings and creating part-time career tracks). Medical schools should address
these obstacles and provide support for faculty with children.
PMID- 9758573
TI - Diagnosis of familial Mediterranean fever by a molecular genetics method.
AB - BACKGROUND: Familial Mediterranean fever is a recessively inherited disorder
characterized by episodes of fever with abdominal pain, pleurisy, or arthritis.
The familial Mediterranean fever gene, designated MEFV, was recently cloned, and
at least three missense mutations (M6801, M694V, and V726A) that account for a
large percentage of patients with this disease were identified. OBJECTIVE: To
establish a diagnostic test for familial Mediterranean fever. DESIGN: Cross
sectional study of a convenience sample of patients attending familial
Mediterranean fever clinics. SETTING: Tertiary referral hospitals. PATIENTS: 107
patients with familial Mediterranean fever, their family members, and controls.
MEASUREMENTS: Mutations in the 107 samples were assessed by amplifying genomic
DNA with use of primers that selectively amplify the normal or altered DNA
sequence of the 3 MEFV mutations (amplification refractory mutation system
[ARMS]). Mutations were independently assessed by automated sequencing of genomic
DNA amplified by polymerase chain reaction to evaluate the sensitivity and
specificity of the ARMS assay. RESULTS: The ARMS assay correctly identified
M6801, M694V, and V726A mutations in 82 persons with mutations documented by DNA
sequencing (21 homozygotes, 2 compound heterozygotes, and 59 simple
heterozygotes). Of 7 persons known from family studies to be noncarriers and 18
unrelated persons who were negative for these mutations by sequencing, none had
MEFV mutations according to ARMS. CONCLUSION: The ARMS assay is a rapid, cost
effective, and accurate method for detecting three common mutations in familial
Mediterranean fever.
PMID- 9758575
TI - Effect of proton-pump inhibitor therapy on diagnostic testing for Helicobacter
pylori.
AB - BACKGROUND: Proton-pump inhibitor therapy may cause false-negative results on
Helicobacter pylori diagnostic testing. OBJECTIVE: To determine the frequency and
duration of conversion of urea breath test results from positive to negative in
patients given a proton-pump inhibitor. SETTING: Two urban university
gastroenterology clinics. PATIENTS: Patients infected with H. pylori who had
positive results on urea breath tests. INTERVENTION: Lansoprazole, 30 mg/d for 28
days. MEASUREMENTS: The urea breath test was repeated at 28 days. If the results
were negative, testing was repeated 3, 7, 14, and 28 days after completion of
therapy until the results reverted to positive. RESULTS: 31 (33%) of 93 patients
in whom H. pylori was not eradicated had a negative breath test result while
receiving lansoprazole. The proportions of patients whose breath test results
were positive after completion of lansoprazole therapy were 91% (95% CI, 83% to
96%) at 3 days, 97% (CI, 90% to 99%) at 7 days, and 100% (CI, 96% to 100%) at 14
days. CONCLUSION: Patients should not receive proton-pump inhibitors for 2 weeks
before receiving the urea breath test for H. pylori infection.
PMID- 9758574
TI - Employment after coronary angioplasty or coronary bypass surgery in patients
employed at the time of revascularization.
AB - BACKGROUND: Patients who undergo coronary angioplasty have a shorter
convalescence than those who undergo coronary bypass surgery. This may improve
subsequent employment. OBJECTIVE: To compare employment patterns after coronary
angioplasty or surgery. DESIGN: Multicenter, randomized clinical trial. SETTING:
Seven tertiary care hospitals. PATIENTS: 409 employed patients with multivessel
coronary artery disease. INTERVENTION: Coronary bypass surgery or balloon
angioplasty. MEASUREMENTS: Time to return to work and time spent working during 4
years of follow-up. RESULTS: Patients who underwent angioplasty returned to work
6 weeks sooner than patients who underwent coronary bypass surgery (P < 0.001),
but long-term employment did not differ significantly (P > 0.2). Long-term
employment was significantly lower among patients who were 60 to 64 years of age
(P < 0.001), those who worked less than full-time at study entry (P < 0.001), and
those who had less formal education (P = 0.005). Patients with only one source of
health insurance were more likely to continue working (P = 0.005). CONCLUSIONS:
Faster recovery after angioplasty speeds return to work but does not improve long
term employment, which is primarily associated with nonmedical factors.
PMID- 9758576
TI - Update in women's health.
PMID- 9758577
TI - Infections in patients with chronic lymphocytic leukemia treated with
fludarabine.
AB - BACKGROUND: Fludarabine, a purine analogue with activity in chronic lymphocytic
leukemia, is usually well tolerated. Although serious infections after
fludarabine therapy have been described, a systematic analysis of the risk
factors for such infections in chronic lymphocytic leukemia is lacking.
OBJECTIVE: To determine the risk factors for major infection in patients with
chronic lymphocytic leukemia treated with fludarabine. DESIGN: Retrospective
review of medical records. SETTING: Cancer center. PATIENTS: 402 patients with
chronic lymphocytic leukemia not previously treated or treated with chlorambucil
(with or without prednisone) who received fludarabine (30 mg/m2 of body surface
area per day for 5 days) with or without prednisone at 4-week intervals. RESULTS:
Infections occurred more often in previously treated (144 of 248 [58%]) than in
previously untreated (53 of 154 [34%]) patients (P < 0.001). Listeriosis or
pneumocystosis occurred in 12 of 170 (7%) previously treated patients receiving
fludarabine plus prednisone, 0 of 78 previously treated patients receiving
fludarabine alone, and 2 of 154 (1%) previously untreated patients receiving
fludarabine plus prednisone (P = 0.003). Univariate analysis identified previous
chemotherapy, advanced disease, failure to respond to fludarabine, elevated serum
beta2-microglobulin level (P < 0.001), low serum albumin level (P = 0.024),
elevated serum creatinine concentration (P = 0.008), and low granulocyte count (P
= 0.003) as risk factors for infection. Multivariate analysis identified Rai
stage III or IV (odds ratio, 1.98 [95% CI, 1.17 to 3.94]), previous treatment
(odds ratio, 2.24 [CI, 1.43 to 3.51]), and elevated serum creatinine
concentration (odds ratio, 1.98 [CI, 1.09 to 3.67]) as statistically significant
independent risk factors for major infection. A baseline granulocyte count of
more than 1000 cells/microL was protective (odds ratio, 0.54 [CI, 0.29 to 0.99]).
Five (26%) of 19 patients with a CD4 count less than 50 cells/mL developed
cutaneous zoster compared with 9 (6%) of 139 patients with a CD4 count greater
than 50 cells/mL (P = 0.01). CONCLUSIONS: Fludarabine used in previously treated
patients with chronic lymphocytic leukemia may be associated with infections
involving T-cell dysfunction, such as listeriosis, pneumocystosis, mycobacterial
infections, and opportunistic fungal and viral infections. Prophylaxis or
presumptive therapy should be initiated in the appropriate setting.
PMID- 9758578
TI - A survey of provider experiences and perceptions of preferential access to
cardiovascular care in Ontario, Canada.
AB - BACKGROUND: The public health insurance system in Canada is predicated on equal
access to care for persons in need. OBJECTIVE: To determine the views and
experiences of Ontario physicians and hospital administrators in providing
patients with preferential access to specialized cardiovascular care on the basis
of nonclinical factors. DESIGN: Survey with self-administered questionnaire.
SETTING: Ontario, Canada. PARTICIPANTS: All Ontario cardiologists (n = 268),
cardiac surgeons (n = 68), and hospital chief executives (n = 218) and random
samples of internists (n = 300) and family physicians (n = 300). MEASUREMENTS:
Elicited responses (yes or no) to questions on whether and why preferential
access occurred and whether the respondents had been personally involved in such
a situation. RESULTS: After undeliverable surveys and respondents no longer
involved with acute care were excluded, the eligible response rate was 71.3% (788
of 1105 respondents). More than 80% of physicians and 53% of hospital chief
executives had been personally involved in managing a patient who had received
preferential access on the basis of factors other than medical need. Patients
deemed most likely to receive such treatment were those with personal ties to the
treating physicians (93% [95% CI, 91% to 95%]), high-profile public figures (85%
[CI, 82% to 87%]), and politicians (83% [CI, 80% to 86%]). Physicians were
significantly more likely than chief executives to indicate that hospital board
members (81% and 68%; P < 0.001) and donors to hospital foundations (63% and 42%;
P < 0.001) would receive preferential access. Most respondents indicated that
preferential access was more likely to be provided if patients or families were
well informed, aggressive, or potentially litigious. The survey did not permit
estimation of the frequency of episodes of preferential access. CONCLUSIONS:
Although equality of access is a cornerstone principle of Canada's universal
health care system, some access to specialized cardiovascular services occurs
preferentially on the basis of factors other than clinical need. The actual
magnitude and consequences of this phenomenon remain unknown.
PMID- 9758579
TI - Rethinking nonadherence: historical perspectives on triple-drug therapy for HIV
disease.
AB - The advent of triple-drug therapy for HIV disease has raised the concern that
disadvantaged patients with multiple social problems may be nonadherent to
treatment. Fearing that partial adherence will lead to drug resistance, some
clinicians are withholding these powerful new drugs from such patients. The
historical record demonstrates that labeling patients as nonadherent may be both
stigmatizing and inaccurate. Since 1900, such adjectives as ignorant, vicious,
and recalcitrant have been used to describe patients who do not follow medical
advice. Less judgmental terms, such as nonadherent and noncompliant, are now
used, but these terms still imply that patients should obey physician-imposed
regimens. Studies of nonadherence have consistently shown that the problem is
widespread among all persons and cannot reliably be predicted on the basis of
patient characteristics. This paper argues that physicians should deemphasize the
standard approach of predicting and correcting nonadherent behavior in certain
patients. Rather, clinicians should encourage all HIV-positive patients to devise
individualized treatment plans that can facilitate reliable ingestion of
medication. Although the potential development of resistance to triple-drug
therapy remains an important public health issue, concern about this possibility
must be balanced with respect for patients' rights. Encouraging the active
participation of HIV-positive persons in their own treatment will help avoid
judgmental and inaccurate assessments of patient behavior and may help patients
take medications more successfully.
PMID- 9758580
TI - On being Dr. Mom.
PMID- 9758581
TI - Genetics of familial Mediterranean fever and its implications.
PMID- 9758582
TI - Lyme disease vaccines.
PMID- 9758583
TI - Hemochromatosis and diabetes mellitus.
PMID- 9758584
TI - Dehydroepiandrosterone, insulin-like growth factor-I, and prostate cancer.
PMID- 9758585
TI - Dehydroepiandrosterone and cardiac arrhythmia.
PMID- 9758586
TI - Multiple IgA autoantibodies associated with mefenamic acid.
PMID- 9758587
TI - In the name of medicine.
PMID- 9758588
TI - In the name of medicine.
PMID- 9758589
TI - History corner: wash the sand out of the sponges.
PMID- 9758590
TI - Is it research or quality improvement?
PMID- 9758591
TI - Power perceived is power achieved.
PMID- 9758592
TI - Family-centered perioperative nursing care takes on a new look.
PMID- 9758593
TI - Molecular evolution of spectrin repeats.
PMID- 9758594
TI - Mixed messages: presentation of information in cystic fibrosis-screening
pamphlets.
AB - Written pamphlets are an important source of information for individuals deciding
whether to undergo carrier testing for cystic fibrosis (CF). Adequate
understanding of the condition and reproductive options following the diagnosis
of a fetus with CF are critical to informed decision making. The information
given about CF and reproductive options in 28 pamphlets about carrier testing,
from commercial and noncommercial organizations in the United States and the
United Kingdom, aimed at prenatal and other populations, was assessed. The amount
of information provided about CF showed a range of 1-37 sentences (median 6.5),
with most being relatively neutral and with a minority conveying a positive or a
negative image. Positive sentences were less common in British, U.S. commercial,
and prenatal pamphlets. Statements about life expectancy also varied
considerably, both in the ages provided and in the degree of optimism conveyed.
In addition, the pamphlets varied in the amount of information they provided
about reproductive options following the diagnosis of a fetus with CF. Abortion
was mentioned in just 15 pamphlets, more often in the United Kingdom than in the
United States and more frequently in pamphlets from noncommercial than in those
from commercial organizations. Wide variation in the descriptions of CF and the
reproductive options presented raises concerns about the extent to which any one
pamphlet may present balanced information. The choices about what information to
include in educational materials need to be explicitly considered on the basis of
the message intended to be sent.
PMID- 9758596
TI - Multiple phenotype modeling in gene-mapping studies of quantitative traits: power
advantages.
AB - Genomewide searches for loci influencing complex human traits and diseases such
as diabetes, hypertension, and obesity are often plagued by low power and
interpretive difficulties. Attempts to remedy these difficulties have typically
relied on, and have promoted the use of, novel subject-ascertainment schemes,
larger sample sizes, a greater density of DNA markers, and more-sophisticated
statistical modeling and analysis strategies. Many of these remedies can be
costly to implement. We investigate the utility of a simple statistical model for
the mapping of quantitative-trait loci that incorporates multiple phenotypic or
diagnostic endpoints into a gene-mapping analysis. The approach considers finding
a linear combination of multiple phenotypic values that maximizes the evidence
for linkage to a locus. Our results suggest that substantial increases in the
power to map loci can be obtained with the proposed technique, although the
increase in power obtained is a function of the size and direction of the
residual correlation among the phenotypes used in the analysis. Extensive
simulation studies are described that justify these claims, for cases in which
two phenotypic measures are analyzed. This approach can be easily extended to
cover more-complex situations and may provide a basis for more insightful genetic
analysis paradigms.
PMID- 9758595
TI - An analysis of phenotypic variation in the familial cancer syndrome von Hippel
Lindau disease: evidence for modifier effects.
AB - von Hippel-Lindau disease (VHL) is a dominantly inherited familial cancer
syndrome predisposing to ocular and CNS hemangioblastomas, renal-cell carcinoma
(RCC), and pheochromocytoma. Both interfamilial and intrafamilial variability in
expression is well recognized. Interfamilial differences in pheochromocytoma
susceptibility have been attributed to allelic heterogeneity such that specific
missense germ-line mutations confer a high risk for this complication. However,
in most cases, tumor susceptibility does not appear to be influenced by the type
of underlying VHL mutation. To probe the causes of phenotypic variation, we
examined 183 individuals with germ-line VHL gene mutations, for the presence and
number of ocular tumors. The prevalence of ocular angiomatosis did not increase
with age, and the distribution of these tumors in gene carriers was significantly
different than the expected stochastic distributions. Individuals with ocular
hemangioblastomas had a significantly increased incidence of cerebellar
hemangioblastoma and RCC (hazard ratios 2.3 and 4.0, respectively). The number of
ocular tumors was significantly correlated in individuals of 12 degree
relatedness but not in more distantly related individuals. These findings suggest
that the development of VHL ocular tumors is determined at an early age and is
influenced by genetic and/or environmental modifier effects that act at multiple
sites. Functional polymorphisms in the glutathione-S-transferase M1 gene (GSTM1)
or the cytochrome P450 2D6 gene (CYP2D6) did not show a significant association
with the severity of ocular or renal involvement.
PMID- 9758597
TI - Imprinted expression of SNRPN in human preimplantation embryos.
AB - Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two clinically
distinct neurogenetic disorders arising from a loss of expression of imprinted
genes within the human chromosome region 15q11-q13. Recent evidence suggests that
the SNRPN gene, which is defective in PWS, plays a central role in the imprinting
center regulation of the PWS/AS region. To increase our understanding of the
regulation of expression of this imprinted gene, we have developed single-cell
sensitive procedures for the analysis of expression of the SNRPN gene during
early human development. Transcripts of SNRPN were detected in human oocytes and
at all stages of preimplantation development analyzed. Using embryos heterozygous
for a polymorphism within the SNRPN gene, we showed that monoallelic expression
from the paternal allele occurs by the 4-cell stage. Thus, the imprinting
epigenetic information inherited in the gametes is recognized already in the
preimplantation embryo. The demonstration of monoallelic expression in embryos
means that efficient preimplantation diagnosis of PWS may be made by analysis for
the presence or absence of SNRPN mRNA.
PMID- 9758598
TI - Double heterozygotes for the Ashkenazi founder mutations in BRCA1 and BRCA2
genes.
PMID- 9758599
TI - A chromosomal deletion map of human malformations.
AB - Malformations are common causes of pediatric morbidity and mortality, and genetic
factors are a significant component of their etiology. Autosomal deletions, in
almost all cases, cause a nonspecific embryopathy that presents after birth as
growth failure, mental retardation, and multiple malformations. We have
constructed a chromosome map of autosomal deletions associated with 47 different
congenital malformations, using detailed clinical and cytogenetic information on
1,753 patients with nonmosaic single contiguous autosomal deletions. The 1,753
deletions involved 258 (89%) of 289 possible autosomal bands (by the use of ISCN
400-band nomenclature), giving a total of 4,190 deleted autosomal bands for
analysis. We compared the band distributions of deletions associated with common
major malformations with the distribution of all 1,753 deletions. We noted 283
positive associations between deleted bands and specific malformations, of which
199 were significant (P<.05, P>.001) and 84 were highly significant (P<.001).
These "malformation-associated bands" (MABs) were distributed among 137
malformation-associated chromosome regions (MACRs). An average of 6 MABs in 2.9
MACRs were detected per malformation studied; 18 (6%) of 283 MABs contain a locus
known to be associated with the particular malformation. A further 18 (6%) of 283
are in seven recognized specific malformation-associated aneuploid regions.
Therefore, 36 (26%) of 137 of the MACRs contain an MAB coinciding with a
previously recognized locus or malformation-associated aneuploid region. This map
should facilitate identification of genes important in human development.
PMID- 9758601
TI - mtDNA suggests Polynesian origins in Eastern Indonesia.
PMID- 9758600
TI - Prenatal screening for cystic fibrosis carriers: an economic evaluation.
AB - The cloning of the CFTR gene has made it technically possible to avert the
unwanted birth of a child with cystic fibrosis (CF). Several large trials
offering prenatal CF carrier screening suggest that such screening is practical
and that identified carriers generally use the information obtained. Therefore, a
critical question is whether the cost of such screening is justified. Decision
analysis was performed that used information about choices that pregnant women
were observed to make at each stage in the Rochester prenatal carrier-screening
trial. The cost of screening per CF birth voluntarily averted was estimated to be
$1,320,000-$1,400,000. However, the lifetime medical cost of the care of a CF
child in today's dollars was estimated to be slightly>$1,000,000. Therefore,
despite both the high cost of carrier testing and the relative infrequency of CF
conceptions in the general population, the averted medical-care cost resulting
from choices freely made are estimated to offset approximately 74%-78% of the
costs of a screening program. At present, if it is assumed that a pregnancy
terminated because of CF is replaced, the marginal cost for prenatal CF carrier
screening is estimated to be $8,290 per quality-adjusted life-year. This value
compares favorably with that of many accepted medical services. The cost of
prenatal CF carrier screening could fall to equal the averted costs of CF patient
care if the cost of carrier testing were to fall to $100.
PMID- 9758602
TI - Do human chromosomal bands 16p13 and 22q11-13 share ancestral origins?
PMID- 9758603
TI - Partial triplication of mtDNA in maternally transmitted diabetes mellitus and
deafness.
PMID- 9758604
TI - Support for a chromosome 18p locus conferring susceptibility to functional
psychoses in families with schizophrenia, by association and linkage analysis.
AB - The action of antipsychotic drugs on dopamine receptors suggests that
dopaminergic signal transmission may play a role in the development of
schizophrenia. We tested eight candidate genes (coding for dopamine receptors,
the dopamine transporter, and G-proteins) in 59 families from Germany and Israel,
for association. A P value of .00055 (.0044 when corrected for the no. of markers
tested) was obtained for the intronic CA-repeat marker G-olfalpha on chromosome
18p. The value decreased to .000088 (.0007) when nine sibs with recurrent
unipolar depressive disorder were included. Linkage analysis using SSLP markers
densely spaced around G-olfalpha yielded a maximum two-point LOD score of 3.1 for
a marker 0.5 cM distal to G-olfalpha. Multipoint analysis under the assumption of
heterogeneity supported this linkage-whether the affected pheotype was defined
narrowly or broadly-as did nonparametric linkage (NPL). In 12 families with
exclusively maternal transmission of the disease, the NPL value also supported
linkage to this marker. In order to test for association/linkage disequilibrium
in the presence of linkage, the sample was restricted to independent offspring.
When this sample was combined with 65 additional simplex families (each of them
comprising one schizophrenic offspring and his or her parents), the 124-bp allele
of G-olfalpha was transmitted 47 times and was not transmitted 21 times (P=.009).
These results suggest the existence, on chromosome 18p, of a potential
susceptibility locus for functional psychoses.
PMID- 9758605
TI - Autosomal dominant nocturnal frontal-lobe epilepsy: genetic heterogeneity and
evidence for a second locus at 15q24.
AB - Autosomal dominant nocturnal frontal-lobe epilepsy (ADNFLE) is a recently
identified partial epilepsy in which two different mutations have been described
in the alpha4 subunit of the neuronal nicotinic acetylcholine receptor (CHRNA4).
An additional seven families are presented in which ADNFLE is unlinked to the
CHRNA4 region on chromosome 20q13.2. Seven additional sporadic cases showed no
evidence of defective CHRNA4. One of the families showed evidence of linkage to
15q24, close to the CHRNA3/CHRNA5/CHRNB4 cluster (maximum LOD score of 3.01 with
D15S152). Recombination between ADNFLE and CHRNA4, linkage to 15q24 in one
family, and exclusion from 15q24 and 20q13.2 in others demonstrate genetic
heterogeneity with at least three different genes for ADNFLE. The CHRNA4 gene and
the two known CHRNA4 mutations are responsible for only a minority of ADNFLE.
Although the ADNFLE phenotype is clinically homogeneous, there appear to be a
variety of molecular defects responsible for this disorder, which will provide a
challenge to the understanding of the basic mechanism of epileptogenesis.
PMID- 9758606
TI - Missense and nonsense mutations in the lysosomal alpha-mannosidase gene (MANB) in
severe and mild forms of alpha-mannosidosis.
AB - alpha-Mannosidosis is an autosomal recessive lysosomal-storage disorder caused by
a deficiency of lysosomal alpha-mannosidase activity. This disease shows a wide
range of clinical phenotypes, from a severe, infantile form (type I), which is
fatal at <3-8 years of age, to a less severe, late-onset form (type II), which
ultimately may involve hearing loss, coarse face, mental retardation, and
hepatosplenomegaly. To elucidate the molecular mechanism underlying this disease
in both types of patients, we have used PCR, followed by either SSCP analysis or
direct sequencing, to analyze the 24 exons and intron/exon boundaries of the
alpha-mannosidase gene (MANB) from five patients. Two amino acid substitutions
H72L and R750W, in exons 2 and 18, respectively-and two nonsense mutations-Q639X
and R760X, in exons 15 and 19, respectively-were identified in four type II
patients. One amino acid substitution, P356R, was identified in exon 8 from a
type I patient. This patient and three of the type II patients were homozygous
for their mutations (H72L, P356R, R750W, and R760X) and one type II patient was
heterozygous for the Q639X and R750W mutations. Transfection experiments of COS 7
cells, using the alpha-mannosidase cDNA containing one of the missense mutations
H72L, P356R, or R750W-revealed that each of these mutations dramatically reduces
the enzymatic activity of alpha-mannosidase. These data demonstrate that widely
heterogeneous missense or nonsense mutations of the MANB gene are the molecular
basis underlying alpha-mannosidosis.
PMID- 9758608
TI - Maternal uniparental disomy of chromosome 1 with no apparent phenotypic effects.
PMID- 9758609
TI - Reply to Inglehearn.
PMID- 9758610
TI - On the probability of Neanderthal ancestry.
PMID- 9758614
TI - Allele identical by descent sharing at any point of a chromosome of a sib pair.
PMID- 9758613
TI - How sib pairs reveal linkage.
PMID- 9758612
TI - Adenosine deaminase deficiency: genotype-phenotype correlations based on
expressed activity of 29 mutant alleles.
AB - Adenosine deaminase (ADA) deficiency causes lymphopenia and immunodeficiency due
to toxic effects of its substrates. Most patients are infants with severe
combined immunodeficiency disease (SCID), but others are diagnosed later in
childhood (delayed onset) or as adults (late onset); healthy individuals with
"partial" ADA deficiency have been identified. More than 50 ADA mutations are
known; most patients are heteroallelic, and most alleles are rare. To analyze the
relationship of genotype to phenotype, we quantitated the expression of 29 amino
acid sequence-altering alleles in the ADA-deleted Escherichia coli strain SO3834.
Expressed ADA activity of wild-type and mutant alleles ranged over five orders of
magnitude. The 26 disease-associated alleles expressed 0.001%-0.6% of wild-type
activity, versus 5%-28% for 3 alleles from "partials." We related these data to
the clinical phenotypes and erythrocyte deoxyadenosine nucleotide (dAXP) levels
of 52 patients (49 immunodeficient and 3 with partial deficiency) who had 43
genotypes derived from 42 different mutations, including 28 of the expressed
alleles. We reduced this complexity to 13 "genotype categories," ranked according
to the potential of their constituent alleles to provide ADA activity. Of 31 SCID
patients, 28 fell into 3 genotype categories that could express <=0.05% of wild
type ADA activity. Only 2 of 21 patients with delayed, late-onset, or partial
phenotypes had one of these "severe" genotypes. Among 37 patients for whom
pretreatment metabolic data were available, we found a strong inverse correlation
between red-cell dAXP level and total ADA activity expressed by each patient's
alleles in SO3834. Our system provides a quantitative framework and ranking
system for relating genotype to phenotype.
PMID- 9758611
TI - Familial eosinophilia maps to the cytokine gene cluster on human chromosomal
region 5q31-q33.
AB - Familial eosinophilia (FE) is an autosomal dominant disorder characterized by
peripheral hypereosinophilia of unidentifiable cause with or without other organ
involvement. To localize the gene for FE, we performed a genomewide search in a
large U.S. kindred, using 312 different polymorphic markers. Seventeen affected
subjects, 28 unaffected bloodline relatives, and 8 spouses were genotyped. The
initial linkage results from the genome scan provided evidence for linkage on
chromosome 5q31-q33. Additional genotyping of genetic markers located in this
specific region demonstrated significant evidence that the FE locus is situated
between the chromosome 5q markers D5S642 and D5S816 (multipoint LOD score of
6.49). Notably, this region contains the cytokine gene cluster, which includes
three genes-namely, those for interleukin (IL)-3, IL-5, and
granulocyte/macrophage colony-stimulating factor (GM-CSF)-whose products play
important roles in the development and proliferation of eosinophils. These three
cytokine genes were screened for potential disease-specific mutations by
resequencing of a subgroup of individuals from the present kindred. No functional
sequence polymorphisms were found within the promoter, the exons, or the introns
of any of these genes or within the IL-3/GM-CSF enhancer, suggesting that the
primary defect in FE is not caused by a mutation in any one of these genes but,
rather, is caused by another gene in the area.
PMID- 9758615
TI - Ascertainment corrections based on smaller family units.
AB - Ascertainment concerns the manner by which families are selected for genetic
analysis and how to correct for it in likelihood models. Because such families
are often neither drawn at random nor selected according to well-defined rules,
the problem of ascertainment correction in the genetic analysis of family data
has proved durable. This paper undertakes a systematic study of ascertainment
corrections in terms of smaller distinct units, which will usually be sibships,
nuclear families, or small pedigrees. Three principal results are presented. The
first is that ascertainment corrections in likelihood models for family data can
be made in terms of smaller units, without breaking up the pedigree. The second
is that the appropriate correction for single ascertainment in a unit is the
reciprocal of the sum of the marginal probabilities of all the persons relevant
to its ascertainment, as if affected. The third result is a generalization of the
single ascertainment-correction formula to k-plex ascertainment, in which each
unit has k or more affecteds. The correction is the reciprocal of the sum of the
joint probabilities of all distinct sets of k persons in the unit, as if they
were all affected. In extended families, two additional ascertainment schemes
will be considered and explicit formulas will be presented. One of these schemes
is "uniform-proband-status ascertainment," in which nonmembers of a given unit
have the same chance as members to become probands if they are affected; the
other scheme is the "inverse law of ascertainment," in which the chance that
nonmembers of a unit will become probands for that unit decreases with degree of
relationship. Several specific recommendations are made for further study.
PMID- 9758616
TI - Chromosome 21 disomy in the spermatozoa of the fathers of children with trisomy
21, in a population with a high prevalence of Down syndrome: increased incidence
in cases of paternal origin.
AB - Between April 1991 and December 1994, epidemiological studies detected a
population with a high prevalence of Down syndrome in El Valles, Spain. Parallel
double studies were carried out to determine the parental and the meiotic origins
of the trisomy 21, by use of DNA polymorphisms, and to establish the incidence of
disomy 21 in the spermatozoa of the fathers of affected children, by use of
multicolor FISH. Results show that the overall incidence of chromosome 21 disomy
in the fathers of affected children was not significantly different from that in
the control population (0.31% vs. 0.37%). However, analysis of individual data
demonstrates that two cases (DP-4 and DP-5) with significant increases of disomy
21 (0. 75% and 0.78% vs. 0.37%) correspond to the fathers of the two individuals
with Down syndrome of paternal origin. DP-5 also had a significant increase of
sex-chromosome disomies (0.69% vs. 0.37%) and of diploid spermatozoa (1.13% vs.
0.24%).
PMID- 9758618
TI - Attitudes of deaf adults toward genetic testing for hereditary deafness.
AB - Recent advances within molecular genetics to identify the genes for deafness mean
that it is now possible for genetic-counseling services to offer genetic testing
for deafness to certain families. The purpose of this study is to document the
attitudes of deaf adults toward genetic testing for deafness. A structured, self
completion questionnaire was given to delegates at an international conference on
the "Deaf Nation," held at the University of Central Lancashire in 1997. The
conference was aimed at well-educated people, with an emphasis on Deaf culture
issues. Eighty-seven deaf delegates from the United Kingdom returned completed
questionnaires. The questionnaire had been designed to quantitatively assess
attitudes toward genetics, interest in prenatal diagnosis (PND) for deafness, and
preference for having deaf or hearing children. The results from this study
provide evidence of a predominantly negative attitude toward genetics and its
impact on deaf people, in a population for whom genetic-counseling services are
relevant. Fifty-five percent of the sample thought that genetic testing would do
more harm than good, 46% thought that its potential use devalued deaf people, and
49% were concerned about new discoveries in genetics. When asked about testing in
pregnancy, 16% of participants said that they would consider having PND, and, of
these, 29% said that they would prefer to have deaf children. Geneticists need to
appreciate that some deaf persons may prefer to have deaf children and may
consider the use of genetic technology to achieve this. Any genetic-counseling
service set up for families with deafness can only be effective and appropriate
if clinicians and counselors take into consideration the beliefs and values of
the deaf community at large.
PMID- 9758617
TI - Mutation in the human acetylcholinesterase-associated collagen gene, COLQ, is
responsible for congenital myasthenic syndrome with end-plate
acetylcholinesterase deficiency (Type Ic).
AB - Congenital myasthenic syndrome (CMS) with end-plate acetylcholinesterase (AChE)
deficiency is a rare autosomal recessive disease, recently classified as CMS type
Ic (CMS-Ic). It is characterized by onset in childhood, generalized weakness
increased by exertion, refractoriness to anticholinesterase drugs, and
morphological abnormalities of the neuromuscular junctions (NMJs). The collagen
tailed form of AChE, which is normally concentrated at NMJs, is composed of
catalytic tetramers associated with a specific collagen, COLQ. In CMS-Ic
patients, these collagen-tailed forms are often absent. We studied a large family
comprising 11 siblings, 6 of whom are affected by a mild form of CMS-Ic. The
muscles of the patients contained collagen-tailed AChE. We first excluded the
ACHE gene (7q22) as potential culprit, by linkage analysis; then we mapped COLQ
to chromosome 3p24.2. By analyzing 3p24.2 markers located close to the gene, we
found that the six affected patients were homozygous for an interval of 14 cM
between D3S1597 and D3S2338. We determined the COLQ coding sequence and found
that the patients present a homozygous missense mutation, Y431S, in the conserved
C-terminal domain of COLQ. This mutation is thought to disturb the attachment of
collagen-tailed AChE to the NMJ, thus constituting the first genetic defect
causing CMS-Ic.
PMID- 9758620
TI - A gene for Meckel syndrome maps to chromosome 11q13.
AB - Meckel syndrome (MKS) is a rare autosomal recessive lethal condition of unknown
origin, characterized by (i) an occipital meningo-encephalocele with (ii)
enlarged kidneys, with multicystic dysplasia and fibrotic changes in the portal
area of the liver and with ductal proliferation, and (iii) postaxial polydactyly.
A gene responsible for MKS in Finland has been mapped to chromosome 17q21-q24.
Studying a subset of Middle Eastern and northern African MKS families, we have
recently excluded the chromosome 17 region and have suggested a genetic
heterogeneity. In the present study, we report on the mapping of a second MKS
locus (MKS2) to chromosome 11q13, by homozygosity mapping in seven families that
do not show linkage to chromosome 17q21-q24 (maximum LOD score 4.41 at
recombination fraction .01). Most interestingly, the affected fetuses of southern
Tunisian ancestry shared a particular haplotype at loci D11S911 and D11S906,
suggesting that a founder effect is involved. Our observation gives support to
the clinical and genetic heterogeneity of MKS.
PMID- 9758619
TI - An autosomal genomic scan for loci linked to type II diabetes mellitus and body
mass index in Pima Indians.
AB - Genetic factors influence the development of type II diabetes mellitus, but
genetic loci for the most common forms of diabetes have not been identified. A
genomic scan was conducted to identify loci linked to diabetes and body-mass
index (BMI) in Pima Indians, a Native American population with a high prevalence
of type II diabetes. Among 264 nuclear families containing 966 siblings, 516
autosomal markers with a median distance between adjacent markers of 6.4 cM were
genotyped. Variance-components methods were used to test for linkage with an age
adjusted diabetes score and with BMI. In multipoint analyses, the strongest
evidence for linkage with age-adjusted diabetes (LOD = 1.7) was on chromosome
11q, in the region that was also linked most strongly with BMI (LOD = 3.6).
Bivariate linkage analyses strongly rejected both the null hypothesis of no
linkage with either trait and the null hypothesis of no contribution of the locus
to the covariation among the two traits. Sib-pair analyses suggest additional
potential diabetes-susceptibility loci on chromosomes 1q and 7q.
PMID- 9758621
TI - Analysis of mutations in the XPD gene in Italian patients with
trichothiodystrophy: site of mutation correlates with repair deficiency, but gene
dosage appears to determine clinical severity.
AB - Xeroderma pigmentosum (XP) complementation group D is a heterogeneous group,
containing patients with XP alone, rare cases with both XP and Cockayne syndrome,
and patients with trichothiodystrophy (TTD). TTD is a rare autosomal recessive
multisystem disorder associated, in many patients, with a defect in nucleotide
excision repair; but in contrast to XP patients, TTD patients are not cancer
prone. In most of the repair-deficient TTD patients, the defect has been assigned
to the XPD gene. The XPD gene product is a subunit of transcription factor TFIIH,
which is involved in both DNA repair and transcription. We have determined the
mutations and the pattern of inheritance of the XPD alleles in the 11 cases
identified in Italy so far, in which the hair abnormalities diagnostic for TTD
are associated with different disease severity but similar cellular
photosensitivity. We have identified eight causative mutations, of which four
have not been described before, either in TTD or XP cases, supporting the
hypothesis that the mutations responsible for TTD are different from those found
in other pathological phenotypes. Arg112his was the most common alteration in the
Italian patients, of whom five were homozygotes and two were heterozygotes, for
this mutation. The presence of a specifically mutated XPD allele, irrespective of
its homozygous, hemizygous, or heterozygous condition, was always associated with
the same degree of cellular UV hypersensitivity. Surprisingly, however, the
severity of the clinical symptoms did not correlate with the magnitude of the DNA
repair defect. The most severe clinical features were found in patients who
appear to be functionally hemizygous for the mutated allele.
PMID- 9758622
TI - Assignment of the locus for congenital lactase deficiency to 2q21, in the
vicinity of but separate from the lactase-phlorizin hydrolase gene.
AB - Congenital lactase deficiency (CLD) is an autosomal recessive, gastrointestinal
disorder characterized by watery diarrhea starting during the first 1-10 d of
life, in infants fed lactose-containing milks. Since 1966, 42 patients have been
diagnosed in Finland. CLD is the most severe form of lactase deficiency, with an
almost total lack of lactase-phlorizin hydrolase (LPH) activity on jejunal
biopsy. In adult-type hypolactasia, the most common genetic enzyme deficiency in
humans, this enzyme activity is reduced to 5%-10%. Although the activity of
intestinal LPH has been found to be greatly reduced in both forms, the molecular
pathogenesis of lactase deficiencies is unknown. On the basis of the initial
candidate-gene approach, we assigned the CLD locus to an 8-cM interval on
chromosome 2q21 in 19 Finnish families. At the closest marker locus, a specific
allele 2 was present in 92% of disease alleles. On the basis of a genealogical
study, the CLD mutation was found to be enriched in sparsely populated eastern
and northern Finland, because of a founder effect. The results of both the
genealogical study and the haplotype analysis indicate that one major mutation in
a novel gene causes CLD in the Finnish population. Consequently, the critical
region could be restricted further, to an approximately 350-kb interval, by
ancient-haplotype and linkage-disequilibrium analyses. Surprisingly, the LPH gene
was shown to lie outside the critical CLD region, excluding it as a causative
gene for CLD. The LPH locus was found to reside >2 Mb from the critical CLD
region.
PMID- 9758623
TI - Methylation levels at selected CpG sites in the factor VIII and FGFR3 genes, in
mature female and male germ cells: implications for male-driven evolution.
AB - Transitional mutations at CpG dinucleotides account for approximately a third of
all point mutations. These mutations probably arise through spontaneous
deamination of 5-methylcytosine. Studies of CpG mutation rates in disease-linked
genes, such as factor VIII and FGFR3, have indicated that they more frequently
originate in male than in female germ cells. It has been speculated that these
sex-biased mutation rates might be a consequence of sex-specific methylation
differences between the female and the male germ lines. Using the bisulfite-based
genomic-sequencing method, we investigated the methylation status of the human
factor VIII and FGFR3 genes in mature male and female germ cells. With the
exception of a single CpG, both genes were found to be equally and highly
methylated in oocytes and spermatocytes. Whereas these observations strongly
support the notion that DNA methylation is the major determining factor for
recurrent CpG germ-line mutations in patients with hemophilia and achondroplasia,
the higher mutation rate in the male germ line is apparently not a simple
reflection of sex-specific methylation differences.
PMID- 9758624
TI - Childhood absence epilepsy with tonic-clonic seizures and electroencephalogram 3
4-Hz spike and multispike-slow wave complexes: linkage to chromosome 8q24.
AB - Childhood absence epilepsy (CAE), a common form of idiopathic generalized
epilepsy, accounts for 5%-15% of childhood epilepsies. To map the chromosomal
locus of persisting CAE, we studied the clinical and electroencephalographic
traits of 78 members of a five-generation family from Bombay, India. The model
free affected-pedigree member method was used during initial screening with
chromosome 6p, 8q, and 1p microsatellites, and only individuals with absence
seizures and/or electroencephalogram 3-4-Hz spike- and multispike-slow wave
complexes were considered to be affected. Significant P values of .00000-.02 for
several markers on 8q were obtained. Two-point linkage analysis, assuming
autosomal dominant inheritance with 50% penetrance, yielded a maximum LOD score
(Zmax) of 3.6 for D8S502. No other locus in the genome achieved a significant
Zmax. For five smaller multiplex families, summed Zmax was 2.4 for D8S537 and 1.7
for D8S1761. Haplotypes composed of the same 8q24 microsatellites segregated with
affected members of the large family from India and with all five smaller
families. Recombinations positioned the CAE gene in a 3.2-cM interval.
PMID- 9758625
TI - Close associations between prevalences of dominantly inherited spinocerebellar
ataxias with CAG-repeat expansions and frequencies of large normal CAG alleles in
Japanese and Caucasian populations.
AB - To test the hypothesis that the frequencies of normal alleles (ANs) with a
relatively large number of CAG repeats (large ANs) are related to the prevalences
of the dominant spinocerebellar ataxias (SCAs)-SCA types 1, 2, 3 (Machado-Joseph
disease), 6, and dentatorubral-pallidoluysian atrophy (DRPLA)-we investigated the
relative prevalences of these diseases in 202 Japanese and 177 Caucasian families
and distributions of the number of CAG repeats of ANs at these disease loci in
normal individuals in each population. The relative prevalences of SCA1 and SCA2
were significantly higher in Caucasian pedigrees (15% and 14%, respectively) than
in Japanese pedigrees (3% and 5%, respectively), corresponding to the observation
that the frequencies of large ANs of SCA1 (alleles >30 repeats) and of SCA2
(alleles >22 repeats) were significantly higher in Caucasians than in Japanese.
The relative prevalences of MJD/SCA3, SCA6, and DRPLA were significantly higher
in Japanese pedigrees (43%, 11%, and 20%, respectively) than in Caucasian
pedigrees (30%, 5%, and 0%, respectively), corresponding to the observation that
the frequencies of large ANs of MJD/SCA3 (>27 repeats), SCA6 (>13 repeats), and
DRPLA (>17 repeats) were significantly higher in Japanese than in Caucasians. The
close correlations of the relative prevalences of the dominant SCAs with the
distributions of large ANs strongly support the assumption that large ANs
contribute to generation of expanded alleles (AEs) and the relative prevalences
of the dominant SCAs.
PMID- 9758626
TI - A gene on chromosome 11q23 coding for a putative glucose- 6-phosphate translocase
is mutated in glycogen-storage disease types Ib and Ic.
AB - Glycogen-storage diseases type I (GSD type I) are due to a deficiency in glucose
6-phosphatase, an enzymatic system present in the endoplasmic reticulum that
plays a crucial role in blood glucose homeostasis. Unlike GSD type Ia, types Ib
and Ic are not due to mutations in the phosphohydrolase gene and are clinically
characterized by the presence of associated neutropenia and neutrophil
dysfunction. Biochemical evidence indicates the presence of a defect in glucose-6
phosphate (GSD type Ib) or inorganic phosphate (Pi) (GSD type Ic) transport in
the microsomes. We have recently cloned a cDNA encoding a putative glucose-6
phosphate translocase. We have now localized the corresponding gene on chromosome
11q23, the region where GSD types Ib and Ic have been mapped. Using SSCP analysis
and sequencing, we have screened this gene, for mutations in genomic DNA, from
patients from 22 different families who have GSD types Ib and Ic. Of 20 mutations
found, 11 result in truncated proteins that are probably nonfunctional. Most
other mutations result in substitutions of conserved or semiconserved residues.
The two most common mutations (Gly339Cys and 1211-1212 delCT) together constitute
approximately 40% of the disease alleles. The fact that the same mutations are
found in GSD types Ib and Ic could indicate either that Pi and glucose-6
phosphate are transported in microsomes by the same transporter or that the
biochemical assays used to differentiate Pi and glucose-6-phosphate transport
defects are not reliable.
PMID- 9758627
TI - A missense mutation in the zinc-finger domain of the human hairless gene
underlies congenital atrichia in a family of Irish travellers.
AB - Congenital atrichia is a rare, recessively inherited form of hair loss affecting
both males and females and is characterized by a complete absence of hair
follicles. Recently, a mutation in the human hairless gene was implicated in the
pathogenesis of congenital atrichia. The human hairless gene encodes a putative
single zinc-finger transcription-factor protein with restricted expression in
brain and skin, which is believed to regulate catagen remodeling in the hair
cycle. In this study, we report the identification of a missense mutation in the
zinc-finger domain of the hairless gene in a large inbred family of Irish
Travellers with congenital atrichia. The mutated arginine residue is conserved
among human, mouse, and rat, suggesting that it is of significant importance to
the function of the zinc-finger domain.
PMID- 9758629
TI - Homozygosity mapping of a gene responsible for gelatinous drop-like corneal
dystrophy to chromosome 1p.
AB - Gelatinous drop-like corneal dystrophy (GDLD) is a rare autosomal recessive
disorder characterized clinically by grayish corneal deposits of amyloid and by
severely impaired visual acuity. Most patients require corneal transplantation.
To localize a gene responsible for GDLD, we performed linkage analysis of 10
consanguineous Japanese families with a total of 13 affected members.
Homozygosity mapping provided a maximum LOD score of 9.80 at the D1S2741 marker
locus on the short arm of chromosome 1. Haplotype analysis further defined the
disease locus within a region of approximately 2.6 cM between D1S2890 and
D1S2801.
PMID- 9758628
TI - Deletions in HOXD13 segregate with an identical, novel foot malformation in two
unrelated families.
AB - Synpolydactyly (SPD) is a dominantly inherited congenital limb malformation
consisting of 3/4 syndactyly in the hands and 4/5 syndactyly in the feet, with
digit duplication in the syndactylous web. The condition recently has been found
to result from different-sized expansions of an amino-terminal polyalanine tract
in HOXD13. We report a novel type of mutation in HOXD13, associated in some cases
with features of classic SPD and in all cases with a novel foot phenotype. In two
unrelated families, each with a different intragenic deletion in HOXD13, all
mutation carriers have a rudimentary extra digit between the first and second
metatarsals and often between the fourth and fifth metatarsals as well. This
phenotype has not been reported in any mice with genetic modifications of the
HoxD gene cluster. The two different deletions affect the first exon and the
homeobox, respectively, in each case producing frameshifts followed by a long
stretch of novel sequence and a premature stop codon. Although the affected genes
may encode proteins that exert a dominant negative or novel effect, they are most
likely to act as null alleles. Either possibility has interesting implications
for the role of HOXD13 in human autopod development.
PMID- 9758630
TI - Linkage disequilibrium mapping of the gene for Margarita Island ectodermal
dysplasia (ED4) to 11q23.
AB - Margarita Island ectodermal dysplasia (ED4) is an autosomal recessive disorder
characterized by unusual facies, dental anomalies, hypotrichosis, palmoplantar
hyperkeratosis and onychodysplasia, syndactyly, and cleft lip/cleft palate. We
have used an affected-only DNA-pooling strategy to carry out linkage
disequilibrium mapping of the ED4 gene to 11q23. Haplotype analysis of four
complex Margarita Island ED4 families localized the ED4 gene to an approximately
1-2-Mb interval spanned by just two YACs.
PMID- 9758631
TI - Methods of linkage analysis--and the assumptions underlying them [see comment].
PMID- 9758632
TI - Uniparental disomies in unselected populations.
PMID- 9758633
TI - Complex segregation analyses: uses and limitations.
PMID- 9758634
TI - Bayesian linkage analysis, or: how I learned to stop worrying and love the
posterior probability of linkage.
PMID- 9758635
TI - Transmission disequilibrium, family controls, and great expectations.
PMID- 9758636
TI - A model of elegance.
PMID- 9758637
TI - 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors increase fibrinolytic
activity in rat aortic endothelial cells. Role of geranylgeranylation and Rho
proteins.
AB - 3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (HRIs) have
been recently shown to prevent atherosclerosis progression. Clinical benefit
results from combined actions on various components of the atherosclerotic
lesion. This study was designed to identify the effects of HRI on one of these
components, the endothelial fibrinolytic system. Aortas isolated from rats
treated for 2 days with lovastatin (4 mg/kg body wt per day) showed a 3-fold
increase in tissue plasminogen activator (tPA) activity. In a rat aortic
endothelial cell line (SVARECs) and in human nontransformed endothelial cells
(HUVECs), HRI induced an increase in tPA activity and antigen in a time- and
concentration-dependent manner. In SVARECs, the maximal response was observed
when cells were incubated for 48 hours with 50 micromol/L HRI. An increase of tPA
mRNA was also in evidence. In contrast, HRI inhibited plasminogen activator
inhibitor-1 activity and mRNA. The effects of HRI were reversed by mevalonate and
geranylgeranyl pyrophosphate, but not by LDL cholesterol and farnesyl
pyrophosphate, and were not induced by alpha-hydroxyfarnesyl phosphonic acid, an
inhibitor of protein farnesyl transferase. C3 exoenzyme, an inhibitor of the
geranylgeranylated-activated Rho protein, reproduced the effect of lovastatin on
tPA and plasminogen activator inhibitor-1 activity and blocked its reversal by
geranylgeranyl pyrophosphate. The effect of HRI was associated with a disruption
of cellular actin filaments without modification of microtubules. A disrupter of
actin filaments, cytochalasin D, induced the same effect as lovastatin on tPA,
whereas a disrupter of microtubules, nocodazole, did not. In conclusion, HRI can
modify the fibrinolytic potential of endothelial cells, likely via inhibition of
geranylgeranylated Rho protein and disruption of the actin filaments. The
resulting increase of fibrinolytic activity of endothelial cells may contribute
to the beneficial effects of HRI in the progression of atherosclerosis.
PMID- 9758638
TI - Transgenic mice with increased copper/zinc-superoxide dismutase activity are
resistant to hepatic leukostasis and capillary no-reflow after gut
ischemia/reperfusion.
AB - The objectives of this study were to (1) determine whether transgenic (Tg) mice
overexpressing copper/zinc-superoxide dismutase (CuZn-SOD) are protected from the
deleterious effects of gut ischemia/reperfusion (I/R) and (2) compare the
effectiveness of Tg SOD overexpression in attenuating I/R injury to
intravascularly administered CuZn-SOD or manganese (Mn)-SOD. The accumulation of
fluorescently labeled leukocytes and number of nonperfused sinusoids were
monitored by intravital microscopy in livers of wild-type mice (C57BL/6), CuZn
SOD Tg mice, and wild-type mice receiving either CuZn-SOD or Mn-SOD. All
parameters were measured for 1 hour after release of the occluded (for 15
minutes) superior mesenteric artery. Gut I/R in wild-type mice led to an
increased number of stationary leukocytes, while reducing the number of perfused
sinusoids (capillary no-reflow). All of these responses were significantly
blunted in CuZn-SOD Tg mice, with a corresponding attenuation of liver enzyme
release into plasma. Exogenously administered SOD had little or no effect on gut
I/R-induced leukostasis or capillary no-reflow in the liver. These observations
suggest a role for superoxide in gut I/R-induced leukostasis and hypoxic stress
in the liver. Furthermore, the findings suggest that cellular localization of SOD
activity is an important determinant of the protective actions of this enzyme in
experimental models of I/R injury.
PMID- 9758639
TI - Increased expression of Axl tyrosine kinase after vascular injury and regulation
by G protein-coupled receptor agonists in rats.
AB - Axl is a receptor tyrosine kinase originally identified as a transforming gene
product in human myeloid leukemia cells. Cultured rat vascular smooth muscle
cells also express Axl, where it has been proposed that Axl may play a role in
cell proliferation. In the current study, we tested the hypotheses that Axl
expression would parallel neointima formation in balloon-injured rat carotid, and
that Axl expression would be regulated by growth factors present at sites of
vascular injury. Ribonuclease protection assay showed dynamic increases in Axl
mRNA in vessels, with peak expression 7 and 14 days after injury.
Immunohistochemical analysis confirmed these results and demonstrated that Axl
protein expression was localized primarily to cells of the neointima after
injury. Northern blot analysis indicated increased mRNA expression for the
secreted Axl ligand, Gas6, in injured carotids, with a time course paralleling
that of Axl upregulation. Axl and Gas6 expression were temporally correlated with
neointima formation, suggesting a role for Axl signaling in this process. Other
studies, performed in cultured rat vascular smooth muscle cells, revealed
positive regulation of Axl mRNA expression by thrombin or angiotensin II but not
by basic fibroblast growth factor, platelet-derived growth factor-BB, or
transforming growth factor-ss1. Western blot analysis confirmed these results,
showing that Axl protein expression was specifically increased by thrombin or
angiotensin II. Our results implicate Axl as a potential mediator of vascular
smooth muscle migration and proliferation caused by vascular injury and G protein
coupled receptor agonists.
PMID- 9758640
TI - Animal model that mimics atherosclerotic plaque rupture.
AB - Atherosclerotic plaque rupture is the main cause of coronary thrombosis and
myocardial infarcts. Currently, there is no animal model of plaque disruption. We
have developed a rabbit model in which an atherosclerotic plaque can be ruptured
at will after an inflatable balloon becomes embedded into the plaque.
Furthermore, the pressure needed to inflate the plaque-covered balloon may be an
index of overall plaque mechanical strength. The thoracic aorta of
hypercholesterolemic rabbits underwent mechanical removal of endothelial cells,
and then a specially designed balloon catheter was introduced into the lumen of
the thoracic aorta. As early as 1 month after catheter placement, atherosclerotic
plaque formed around the indwelling balloon. The plaques were reminiscent of
human atherosclerotic lesions, in terms of cellular composition, patterns of
lipid accumulation, and growth characteristics. Intraplaque balloons were
inflated both ex vivo and in vivo, leading to plaque fissuring. The ex vivo
strategy is designed to measure the mechanical strength of the surrounding
plaque, while the in vivo scenario permits an analysis of the plaque rupture
consequences, eg, thrombosis. In addition, our model allows local delivery of
various substances into the plaque. The model can be used to study the
pathogenesis of plaque instability and to design plaque stabilization therapy.
PMID- 9758641
TI - Retinal arterial tone is controlled by a retinal-derived relaxing factor.
AB - The present study provides evidence that retinal tissue may profoundly influence
the retinal arterial smooth muscle cell tone by releasing an unknown retinal
relaxing factor. Isolated bovine retinal arteries with and without adhering
retinal tissue were mounted in a wire myograph for isometric tension recordings.
The maximal contraction induced by prostaglandin F2alpha was 0.95+/-0.7 mN (n=6)
in the presence and 5.15+/-0.76 mN (n=6) in the absence of adhering retinal
tissue. The contractions induced by U-46619, serotonin, and endothelin-1 were
similarly blocked in the presence of retinal tissue. The K+ 120 mmol/L-induced
contraction was not significantly affected (2.8+/-0.7 mN, n=6, in the presence
and 3. 6+/-0.7 mN, n=6, in the absence of retinal tissue). Placing a piece of
bovine retinal tissue in the proximity of a contracted (ie, with prostaglandin
F2alpha) retinal artery induced a complete relaxation of the retinal vessel,
suggesting the involvement of a diffusible chemical vasorelaxant. Also porcine,
canine, and ovine retinal tissue completely relaxed the contracted (with
prostaglandin F2alpha) bovine retinal artery. Other smooth muscle preparations,
including rat mesenteric and renal arteries and rat main bronchi, also relaxed
with the application of a piece of bovine retinal tissue. Incubation of bovine
retinas in a Krebs-Ringer bicarbonate solution yielded a solution that relaxed
isolated precontracted bovine retinal arteries, confirming the involvement of a
diffusible chemical messenger. Hexane extraction, heating the solution to 70
degrees C, or treatment with trypsin did not alter the relaxing properties of the
incubation solution. The characteristics of the retinal relaxing factor do not
correspond with those of nitric oxide, prostanoids, adenosine, acetylcholine, or
any other of the known vasoactive neurotransmitters released from the retina. Our
results suggest that retinal arterial tone is controlled by a diffusible,
hydrophilic, and heat-stable relaxing factor that does not correspond with a
known vasoactive molecule formed within the retina.
PMID- 9758642
TI - A major role for prostacyclin in nitric oxide-induced ocular vasorelaxation in
the piglet.
AB - We studied the mechanisms of retinal and choroidal vasorelaxation elicited by
nitric oxide (NO) using piglet eyes. The NO donors sodium nitroprusside (SNP) and
diethylamine-NONOate caused comparable concentration-dependent relaxation that
was partially (approximately 40%) attenuated by the guanylate cyclase inhibitors
methylene blue and LY83583 and reduced to a lesser extent (approximately 25%) by
the inhibitor of cGMP-dependent kinase, KT 5823. In contrast, NO-induced
dilatation (by NO donors and endogenous NO after stimulation with bradykinin) was
substantially (approximately 70%) diminished by the KCa channel blockers
tetraethylammonium (TEA), charybdotoxin, and iberiotoxin; by the cyclooxygenase
inhibitors indomethacin and ibuprofen; by the prostaglandin I (PGI2) synthase
inhibitor trans-2-phenyl cyclopropylamine (TPC); and by the removal of
endothelium; whereas relaxation of endothelium-denuded vasculature to SNP was
unaltered by indomethacin, TPC, and charybdotoxin but was nearly nullified by
methylene blue and the Kv channel blocker 4-aminopyridine. NO donors
significantly increased PGI2 synthesis and the putative PGI2 receptor-coupled
second messenger cAMP, from ocular vasculature (retinal microvessels and
choroidal perfusate), and this increase in PGI2 formation was markedly reduced by
TPC, tetraethylammonium, charybdotoxin, and/or the removal of endothelium, but it
was only slightly reduced by methylene blue and LY83583. Also, SNP and KCa
channel openers NS1619 and NS004 caused an increase in PGI2 synthesis in cultured
endothelial cells, which was virtually abolished by KCa blockers. Finally,
vasorelaxation to a cGMP analogue, 8-bromo cGMP, and protein kinase G stimulant
beta-phenyl-1,N2-etheno-8-bromoguanosine 3':5'-cyclic monophosphate was mostly Kv
dependent and, in contrast to NO, largely unrelated to PGI2 formation. In
conclusion, data indicate that NO-induced ocular vasorelaxation is partly
mediated by cGMP through its action on smooth muscle, and more importantly, by
stimulating PGI2 formation of endothelial origin via a mechanism mostly
independent of guanylate cyclase, which involves the opening of a KCa channel.
PMID- 9758643
TI - Endothelial NADPH oxidase as the source of oxidants in lungs exposed to ischemia
or high K+.
AB - We have previously demonstrated the generation of reactive oxygen species (ROS)
in cultured bovine pulmonary artery endothelial cells (BPAECs) and in isolated
perfused rat lungs exposed to high K+ and during global lung ischemia. The
present study evaluates the NADPH oxidase pathway as a source of ROS in these
models. ROS production, detected by oxidation of the fluorophore,
dichlorodihydrofluorescein, increased 2.5-fold in BPAECs and 6-fold in rat or
mouse lungs exposed to high (24 mmol/L) K+. ROS generation was markedly inhibited
by diphenyliodonium, a flavoprotein inhibitor, and by the synthetic peptide PR
39, an inhibitor of NADPH oxidase assembly, whereas allopurinol had no effect.
With ischemia (1 hour), ROS generation by rat and mouse lungs increased 7-fold;
PR-39 showed concentration-dependent inhibition of ROS production, with 50%
inhibition at 3 micromol/L PR-39. ROS production in lungs exposed to high K+ or
ischemia was essentially abolished in mice with a "knockout" of gp91(phox), a
membrane-localized cytochrome component of NADPH oxidase; increased ROS
production by these lungs after anoxia/reoxygenation was similar to control. PR
39 also inhibited ischemia and the high K+-mediated increase in lung
thiobarbituric acid reactive substance. Western blotting of BPAECs and
immunocytochemistry of BPAECs and rat and mouse lungs showed the presence of
p47phox, a cytoplasmic component of NADPH oxidase and the putative target for PR
39 inhibition. In situ fluorescence imaging in the intact lung demonstrated that
the increased dichlorofluorescein fluorescence in these models of ROS generation
was localized primarily to the pulmonary endothelium. These studies demonstrate
that ROS production in lungs exposed to ischemia or high K+ results from assembly
and activation of a membrane-associated NAPDH oxidase of the pulmonary
endothelium.
PMID- 9758644
TI - Infection of human fetal cardiac myocytes by a human immunodeficiency virus-1
derived vector.
AB - Cardiomyopathy associated with HIV-1 infection is a well-recognized complication.
However, it is unknown whether direct cardiomyocyte infection is involved in the
pathogenesis of the cardiomyopathy. An HIV-1-based lentiviral vector and wild
type HIV-1 were used to infect human fetal cardiac myocytes in a primary culture.
Quantitative polymerase chain reaction, viral p24 antigen determination, and
immunofluorescence were used to detect the synthesis of HIV-1 DNA and proteins
after the infection. High-efficiency infection occurred using the HIV-1-based
lentiviral vector, although no infection occurred with the wild-type HIV-1
strain. Dual-labeling immunofluorescence for HIV-1 proteins and myosin confirmed
that cardiomyocytes were infected. This in vitro analysis suggests that direct
myocyte infection with wild-type HIV-1 may not be involved in the pathogenesis of
HIV-1 cardiomyopathy. However, HIV-1-based vectors may prove useful for ex vivo
cardiovascular gene therapy.
PMID- 9758645
TI - Cardiac angiotensin II receptors are upregulated by long-term inhibition of
nitric oxide synthesis in rats.
AB - It has been shown that nitric oxide (NO) may regulate angiotensin II (Ang II)
receptors in vitro. To determine whether the chronic inhibition of NO synthesis
upregulates cardiac Ang II receptors in a rat model, we evaluated the in vivo
effect of Nomega-nitro-L-arginine methyl ester (L-NAME) on several Ang II
receptors and on the expression of AT1 receptor mRNA in heart tissue. The chronic
administration of L-NAME to normal rats increased the arterial blood pressure.
The number of AT1 and AT2 receptors was increased, with no change in affinity,
during the first week of L-NAME administration but returned to control levels
after 4 weeks of treatment. The AT1 receptor mRNA was changed parallel to AT1
receptor number. Inflammatory changes (monocyte infiltration and myofibroblast
formation) in perivascular areas surrounding coronary vessels and myocardial
interstitial spaces were observed during the first week. The immunohistochemistry
revealed that myofibroblasts expressed AT1 receptor. AT1 receptor blockade or
cotreatment with L-arginine, but not cotreatment with hydralazine, prevented the
L-NAME-induced increase in Ang II receptors and inflammatory changes. In
conclusion, rat cardiac Ang II receptors are upregulated at an early phase of
chronic inhibition of NO synthesis. This may contribute to cardiovascular
inflammatory changes in an early phase and to remodeling at the later phase,
which occurs after inhibition of NO synthesis.
PMID- 9758646
TI - Differential activation of cardiac c-jun amino-terminal kinase and extracellular
signal-regulated kinase in angiotensin II-mediated hypertension.
AB - Two subgroups of mitogen-activated protein kinases, c-jun NH2-terminal kinase
(JNK) and extracellular signal-regulated kinase (ERK), are thought to be involved
in cultured cardiac myocyte hypertrophy and gene expression. To examine the in
vivo activation of these kinases, we measured cardiac JNK and ERK activities in
conscious rats subjected to acute or chronic angiotensin II (Ang II) infusion, by
using in-gel kinase methods. About 50 mm Hg rise in blood pressure by Ang II
(1000 ng . kg-1 . min-1) infusion caused larger activation of left ventricular
JNK than ERK, via the AT1 receptor. In spite of short duration (about 30 minutes)
of maximal blood pressure elevation by Ang II, JNK sustained the peak value (more
than 5-fold increase) from 15 minutes up to at least 3 hours. Similar activation
of JNK was seen in the right ventricle. Thus, cardiac JNK activation by Ang II
seems to be in part mediated by its direct action via the AT1 receptor. The dose
response relationships for Ang II-induced rises in blood pressure and cardiac JNK
and ERK activation indicated that cardiac JNK or ERK was not activated by a mild
increase in blood pressure and that cardiac JNK was activated by Ang II-mediated
hypertension in a more sensitive manner than ERK. Cardiac hypertrophy, induced by
chronic Ang II infusion, was preceded by JNK activation without ERK activation.
Furthermore, gel mobility shift analysis showed that cardiac JNK activation was
followed by increased activator protein-1 DNA binding activity due to c-Fos and c
Jun. These results provided the first evidence for the preferential activation of
cardiac JNK in Ang II-induced hypertension and suggested that JNK might play some
role in Ang II-induced cardiac hypertrophic response in vivo. However, further
study is needed to elucidate the role of JNK in cardiac hypertrophy in vivo.
PMID- 9758647
TI - Adenosine mediates sustained adrenergic desensitization in the rat heart via
activation of protein kinase C.
AB - Adenosine attenuates the myocardial metabolic and contractile responses induced
by ss-adrenergic stimulation. Our study was conducted to investigate the
longevity of this antiadrenergic action after adenosine exposure. Adenosine (33
micromol/L) was infused into isolated perfused rat hearts for 1, 5, 30, or 60
minutes, and the adrenergic responsiveness (AR) to isoproterenol (10(-8) mol/L)
was determined at the end of each infusion period and during a 45-minute
adenosine washout period. Interstitial levels of adenosine, as determined from
epicardial surface transudates, returned to preinfusion levels within 10 minutes
of washout. The duration of adenosine infusion had no effect on the extent of
attenuation of AR at the end of the infusion. Whereas AR returned to preadenosine
levels with washout of shorter adenosine infusions (1 and 5 minutes), there was a
slow and incomplete recovery of AR after the longer exposures (30 and 60 minutes)
to adenosine. The magnitude of this persistent antiadrenergic effect (PAE) of
adenosine at 15 minutes of washout was proportional to the epicardial
concentration of adenosine during infusion of the nucleoside. Infusion of
adenosine either with the nonselective adenosine receptor antagonist 8-p
sulfophenyl theophylline or with the selective A1-receptor antagonist 1,3
dipropyl, 8-cyclopentylxanthine, abolished the PAE during the washout period. In
addition, the PAE could be demonstrated only with the selective A1-receptor
agonist 2-chloro-N6-cyclopentyladenosine and not with the selective A3-receptor
agonist 4-aminobenzyl-5'-N methylcarboxamido-adenosine. When the protein kinase C
(PKC) inhibitor chelerythrine was coadministered with adenosine, the PAE of
adenosine was not apparent during adenosine washout. A 30-minute infusion of
phenylephrine, an alpha-adrenergic agonist that enhances PKC activity, produced a
PAE that lasted for up to 30 minutes of washout. This effect was prevented by the
coinfusion of chelerythrine. Thus, it is concluded that the PAE of adenosine is
determined by the myocardial concentration of this nucleoside and is manifested
when myocardial concentrations of adenosine returned to baseline levels.
Moreover, a 5-minute duration of adenosine exposure is required for the
expression of the PAE. This latter effect seems to be dependent on adenosine
induced PKC activation via A1-receptors.
PMID- 9758649
TI - Introduction
PMID- 9758648
TI - Novel vasodilator released by retinal tissue.
PMID- 9758650
TI - Corneal topography in LASIK.
AB - Corneal topography plays an important role in laser in situ keratomileusis
(LASIK). Preoperative screening permits the detection of keratoconus and other
corneal shape anomalies that may be a contraindication for refractive surgery.
Monitoring the progress of the surgical outcome with topography is helpful to
detect postoperative complications such as decentration and clinically
significant irregular astigmatism. LASIK compares favorably with PRK for the
treatment of low to moderate myopia in terms of early achievement of refractive
stability, but induction of modest amounts of irregular astigmatism can be a
concern.
PMID- 9758651
TI - Outcomes of spherocylinder treatments in the comprehensive refractive surgery
LASIK study.
AB - The CRS LASIK Study is a surgeon-sponsored collaborative project to evaluate
LASIK outcomes with the Summit and VISX lasers. The current report includes 3
month outcomes in the first group of patients who underwent spherocylindrical
corrections of 1 to 10 diopters of myopia and 1 to 4 diopters of astigmatism with
the Summit Apex Plus and VISX Star lasers. Cohort selection criteria were applied
to select 911 eyes that underwent surgery between April 1, 1996 and October 1,
1997 in the range of study. Eyes with preoperative best spectacle-corrected
visual acuity of worse than 20/40 (0.5) were excluded. Outcomes were stratified
according to myopic treatment range. One day uncorrected visual acuity was 20/40
or better in 83% of eyes with both lasers. At 3 months, 20/40 uncorrected acuity
was found in 93% of Summit and 90% of VISX eyes in the -1.00 to -4.00 D group, in
88% of Summit and 84% of VISX eyes in the -4.01 to -7.00 D group, and in 67% of
Summit and 70% of VISX eyes in the -7.01 to -10 D group. Three-month manifest
refractive outcomes in the -1.00 to -4. 00 D group were within +/- 1 D of target
in 91% of the Summit eyes, and 89% of the VISX Eyes. In the -4.01 to -7.00 D
range, 72% of the Summit eyes and 74% of the VISX eyes fell within +/- 1 D, and
in the -7.01 to -10 D range, the rates were 53% for Summit and 56% for VISX. No
eyes lost two lines or more acuity with either laser. Three-month visual and
refractive outcomes in LASIK are comparable with the Summit Apex Plus and VISX
Star lasers. Loss of BSCVA of two lines or more was not seen. CRS LASIK Study
protocols are ongoing to provide longer follow-up and to study other refractive
indications.
PMID- 9758652
TI - Regression after LASIK for the treatment of myopia: the role of the corneal
epithelium.
AB - Factors responsible for postoperative regression are still unknown but
postoperative epithelial hyperplasia might play an important role. To evaluate
the role of the corneal epithelium on regression after laser in situ
keratomileusis (LASIK), the thickness of the epithelium was measured in 18 eyes
preoperatively and at various postoperative intervals. Measurements of the
epithelial thickness were taken using a high-frequency (50 MHz) ultrasound device
and measurements were correlated with the postoperative refraction. In all eyes,
preoperative epithelial thickness was between 34 and 44 microm. In contrast,
after surgery, values were between 35 and 111 microm. In eyes with a refractive
outcome of +/-1.0 diopter of that intended, there was an increase of the
epithelial thickness of less than 5 microm postoperatively. In contrast, eyes
with severe regression showed a significant increase in the thickness in the
epithelium after LASIK. In our patient group, regression of the attempted
correction was related to postoperative epithelial hyperplasia. Broadly speaking,
an increase of 10 microm epithelial thickness resulted in a 1 diopter regression.
Mechanical and/or pharmaceutical factors controlling postoperative epithelial
hyperplasia would be beneficial.
PMID- 9758653
TI - LASIK for hyperopia and hyperopic astigmatism--results of a pilot study.
AB - Laser-assisted in situ keratomileusis (LASIK) was evaluated in hyperopia and
hyperopic astigmatism. LASIK was safe and effective in spherical hyperopia up to
+5 D and acceptable in toric hyperopia up to +5 D but results were poor in
hyperopia of more than +5 D.
PMID- 9758654
TI - Hg2+ removal by genetically engineered Escherichia coli in a hollow fiber
bioreactor.
AB - Escherichia coli cells engineered to express an Hg2+ transport system and
metallothionein accumulated Hg2+ effectively over a concentration range of 0.2-4
mg/L in batch systems. Bioaccumulation was selective against other metal ions and
resistant to changes in ambient conditions such as pH, ionic strength, and the
presence of common metal chelators or complexing agents (Chen, S.-L.; Wilson, D.
B. Appl. Environ. Microbiol. 1997, 63, 2442-2445; Biodegradation 1997, 8, 97
103). Here we report the characterization of the bioaccumulation system based on
its kinetics and an isotherm. Bioaccumulation was rapid and followed Michaelis
Menten kinetics. A hollow fiber bioreactor was constructed to retain the
genetically engineered cells. The bioreactor was capable of removing and
recovering Hg2+ effectively at low concentrations, reducing a 2 mg/L solution to
about 5 microgram/L. A mathematical equation that quantitatively described Hg2+
removal by the bioreactor provides a basis for the optimization and extrapolation
of the bioreactor. The genetically engineered E. colicells and the bioreactor
system have excellent properties for bioremediation of Hg2+-contaminated
environments.
PMID- 9758655
TI - Modeling and analysis of co-immobilized aerobic/anaerobic mixed cultures.
AB - Systems of co-immobilized microorganisms are highly effective for conducting two
or more consecutive bioprocesses within close proximity of the source and the
sink of substrates. In this work, a general model of a co-immobilized
aerobic/anaerobic bacterial system was developed and analyzed. The model was used
to optimize pellet design and to study the effect of slow cell growth on process
efficiency. The analysis demonstrated that co-immobilization of bacterial species
accelerates the rate of biotransformation and provides complete transformation of
toxic intermediates.
PMID- 9758656
TI - Novel membrane bioreactor with gas/liquid two-phase flow for high-performance
degradation of phenol.
AB - The use of a membrane bioreactor with cell retention to achieve high biomass
concentrations has been examined for phenol degradation by the bacteria
Alcaligenes eutrophus. This process is particularly interesting for toxic
substrates as the hydraulic dilution rate and the growth rate are independently
controlled. In the case of a transitory excess of phenol, this potentially toxic
situation can be overcome by modifying the substrate concentration or the
dilution rate without any loss of cells. The injection of a gas phase at the
filter inlet increased both the permeate flow rate (by a factor of 1. 75) and the
oxygen transfer capacity (by a factor of 1.5). This has enabled the cell
concentration to reach a maximal value of 60 g L-1 with a hydraulic dilution rate
of 0.5 h-1 and a phenol feed concentration of 8 g L-1. The volumetric
productivity of this process corresponds to a phenol degradation rate approaching
100 kg m-3 day-1. The on-line measurement of the characteristic yellow color of 2
hydroxymuconate semialdehyde, a metabolic intermediate of the phenol degradation
pathway, in the permeate provides an interesting basis for process control of
phenol supply into the reactor since the color intensity correlates directly to
the specific rate of phenol degradation.
PMID- 9758657
TI - Transport in a grooved perfusion flat-bed bioreactor for cell therapy
applications.
AB - This study considers the transport of oxygen (a growth-associated solute) and
lactate (a metabolic byproduct) in a flat-bed perfusion chamber modified to
retain cells through the addition of grooves, perpendicular to the direction of
flow, at the chamber bottom. The chamber has been successfully applied to
hematopoietic cell culture and may be useful for other basic and applied
biomedical applications. The objective of this study is to characterize the
culture environment in terms of solute transport under various operational
conditions. This will allow one to improve the design and operating strategy of
the perfusion system for maximizing cell numbers. The system is numerically
simulated using the finite element package FIDAP. The reaction kinetics
describing oxygen uptake by cells are simplified to zero order to give an upper
bound for the oxygen consumption. A flat-bed chamber without grooves is
considered here as a benchmark. We show that the growth environment is not oxygen
limited (local oxygen concentration above 10 microM) for a variety of flow rates
and culture conditions (qO2 = 0.1 micromol/(10(6) cells h)). With a medium flow
rate of 2.5 mL/min through the reactor, the model predicts that the 29-cm2
reactor can support at least 33.4 x 10(6) total cells when the inlet medium is in
equilibrium with high (20%) oxygen concentration. The culture becomes oxygen
limited however for the same flow rate for low (5%) oxygen concentration and can
only support 7.2 x 10(6) total cells. Comparison of grooved vs nongrooved
chambers reveals that the presence of grooves only affects solute transport on a
local scale. This result is attributed to the small size (200 microgram) of the
cavities relative to the chamber dimensions. The comparison also yields an
empirical relation that allows for rapid estimation of oxygen and lactate
concentrations in the grooves using only the numerical simulation of the simpler
nongrooved chamber. Finally, our investigation shows that, while decreasing the
spacing between cavities decreases the total number of cells the reactor can
support, the efficiency of the reactor is increased by 25% (on an area basis)
without growth restriction.
PMID- 9758658
TI - Efficient production of L-(+)-lactic acid using mycelial cotton-like flocs of
Rhizopus oryzae in an air-lift bioreactor.
AB - L-(+)-Lactic acid production was enhanced in a culture of Rhizopus oryzae by
induction of a mycelial flocs morphology. By conventional culture the morphology
of R. oryzae is that of a pellet-like cake; however, when mineral support and
poly(ethylene oxide) are added to the culture, the morphology of R. oryzae takes
on a cotton-like appearance. The formation of these cotton-like mycelial flocs
was induced by the addition of 5 ppm poly(ethylene oxide) into a 12-14 h culture
containing 3 g/L of the mineral support before the formation of the conventional
pellet morphology. The cotton-like flocs were also formed in cultures grown in an
air-lift bioreactor. This morphology allowed effective mass transfer inside the
flocs and effective fluidity of culture broth in an air-lift bioreactor. L-(+)
Lactic acid concentration produced by mycelial flocs in an air-lift bioreactor,
with the support and poly(ethylene oxide), was 104.6 g/L with a yield of 0.87
using 120 g/L of glucose as the substrate; for this culture without both, the
concentration was 43.2 g/L. These results demonstrate that cotton-like mycelial
flocs are the optimal morphology for use in the air-lift bioreactor culture of R.
oryzae.
PMID- 9758659
TI - Higher productivity of growth-arrested Chinese hamster ovary cells expressing the
cyclin-dependent kinase inhibitor p27.
AB - We constructed stable Chinese hamster ovary (CHO) cell lines which conditionally
and coordinately express the model product gene secreted alkaline phosphatase
(SEAP) and one of the cytostatic genes p21, p27, and p53175P, a p53 mutant
deficient in apoptotic but not cell-cycle arrest function. The use of dicistronic
expression technology allowed the conditional expression of the model product
gene and the cytostatic gene in a coordinated fashion from a single expression
unit under the control of the tetracycline-responsive promoter PhCMV-1. Due to
the presence of a cytostatic gene in the multicistronic expression unit, the
growth behavior of the engineered CHO cell lines could be controlled by the
addition or withdrawal of the exogenous agent tetracycline to or from the cell
culture medium. Withdrawal of tetracycline resulted in sustained growth arrest of
the stable cell lines for a prolonged period. The growth arrest of such cell
lines was found to be accompanied by a 10-15-fold increase in their production of
SEAP per cell. This controlled proliferation technology allows the design of a
novel two-stage production process which consists of a proliferation phase
leading to the desired cell density, followed by an extended production phase
during which the cells remain growth-arrested and increase cell-specific
production of a heterologous protein.
PMID- 9758660
TI - Scale-up and optimization of the low-temperature inducible cspA promoter system.
AB - The performance of the major Escherichia coli cold-shock promoter in directing
the synthesis of recombinant proteins at low temperatures was investigated in
batch fermentations using a plasmid-encoded transcriptional gene fusion between
the cspA promoter region and the lacZ gene. Rapid synthesis of beta-galactosidase
was observed when the fermentation broth was chilled to 15 degreesC using a
variety of cooling profiles, including one modeling the heat-transfer
characteristics of a 60-L pilot plant unit. A linear cooling rate of 0.5
degreesC/min led to optimum recovery yields. For all single-temperature downshift
experiments, however, the promoter became repressed 60-120 min after initiation
of cooling. Both temperature cycling between 15 and 25 degreesC and stepwise
temperature downshifts between 37, 29, 21, and 13 degreesC led to multiple
inductions of the cspA promoter. Nevertheless, high-efficiency reinduction was
only observed during the first temperature pulse when the former strategy was
used and when the cells were held at intermediate temperatures for less than 60
min or more than 120 min in the case of successive downshifts. Promoter
repression was abolished in host cells bearing a null mutation in the gene
encoding the ribosomal binding factor RbfA, leading to the constitutive and high
level expression of beta-galactosidase for 7 h postshift when shake flask
cultures were transferred from 42 to 23 degreesC. The suitability of rbfA cells
for cspA-driven recombinant protein production was confirmed in high-density fed
batch fermentations. Our results are consistent with the existence of a cold
shock-induced repressor molecule that must accumulate at a threshold
concentration before interfering with the production of proteins placed under
cspA transcriptional control.
PMID- 9758661
TI - Solubilization of recombinant ovine growth hormone with retention of native-like
secondary structure and its refolding from the inclusion bodies of Escherichia
coli.
AB - Ovine growth hormone was expressed in Escherichia coli in the form of inclusion
bodies using the pQE-30 expression vector. In a simple fed-batch fermentation,
800 mg/L of recombinant ovine growth hormone (r-oGH) was produced at a cell
concentration of 12 g dry cell weight/L. Inclusion bodies were isolated from
cells with >95% purity by extensive washing using detergent, and the r-oGH from
the purified inclusion bodies was solubilized in 2 M Tris-HCl buffer at pH 12
containing 2 M urea. The r-oGH solubilized in the above conditions exhibited
considerable secondary structure as determined by circular dichroism spectra and
was immunologically active. Solubilization of the inclusion body protein with
retention of native-like secondary structure gave higher yields during refolding.
To suppress protein aggregation, refolding was carried out in gel filtration
column. Refolding, buffer exchange, and the purification of monomeric r-oGH from
aggregated complex was achieved in a single step using gel filtration
chromatography. More than 60% of the initial inclusion body protein was refolded
into a native-like conformation by the use of this procedure. The refolded
protein was characterized by circular dichroism, fluorescence, SDS-PAGE, Western
blotting, and radio receptor binding assay and found to be similar to native,
pituitary-derived, ovine growth hormone.
PMID- 9758664
TI - Displacement chromatography using the UNO continuous bed column as a stationary
phase
AB - Displacement separations of biopolymers are even more restricted in regard to the
upper applicable limit of the flow rate than elution chromatographic ones, when
conventional columns packed with porous particles are used. Bio-Rad has recently
introduced a new column type, the UNO column, which contrary to conventional HPLC
columns is not packed with particles but consists of a continuous porous polymer
rod. The plate height of this continuous bed column was found to be nearly
independent of the flow rate within the investigated range (0.01-4.5 mL/min, 1.56
701.6 cm/h). The strong ion exchanger columns UNO Q1 (7 x 35 mm, 1.3 mL) and UNO
Q6 (12 x 53 mm, 6 mL) were investigated as stationary phases for protein
displacement chromatography at elevated flow rates. With the UNO column,
displacement separations of alpha-lactalbumin and beta-lactoglobulin (displacer:
poly(acrylic acid), Mw 5100) were still possible at flow rates that were 1 order
of magnitude higher than those applicable to conventional columns of similar
dimensions. In fact the flow rate was limited by the necessity to collect the
protein-containing fraction fast enough for an adequate monitoring of the
separation rather than by a loss in resolution. While the UNO Q1 column did not
allow for the full development of the displacement train, 50 mg of protein could
be separated using the UNO Q 6 column. Recoveries were well over 95% in this
case. More than 50% of the alpha-lactalbumin was collected in pure and
concentrated form (concentration by a factor of 2). The steric mass action model
was used to optimize the displacer concentration.
PMID- 9758663
TI - Selective adsorption/recovery of Pb, Cu, and Cd with multiple fixed beds
containing immobilized bacterial biomass.
AB - Fixed-bed columns packed with calcium alginate (CA)-immobilized biomass of
Pseudomonas aeruginosa PU21 were utilized to remove lead (Pb), copper (Cu), and
cadmium (Cd) from the contaminated water. In the absence of competing metals,
saturation capacity of CA-immobilized cells in batch operations was 1.60, 2.42,
and 1.06 mmol/g, for Pb, Cu, and Cd, respectively. The Langmuir constants (K)
obtained from the Langmuir isotherm were 157.6, 4.2, and 3.7 mM-1 for Pb, Cu, and
Cd, respectively. Results from single-metal biosorption with 10-cm immobilized
cell columns show that, for an influent metal concentration of 193 microM, the
total capacities for Pb, Cu, and Cd, respectively, were 5.12, 4.03, and 3.48
mmol, which is nearly 25-30% higher than those obtained from columns containing
only cell-free CA matrix. With the influent containing ternary mixtures of Pb,
Cu, and Cd, columns with immobilized cells exhibited predominant selectivity to
Pb, whereas in the cell-free columns, the dominance of Pb adsorption reduced,
along with an appreciable increase in the adsorption of Cu. The metal-laden
columns were regenerated by elution with HCl solution (pH 2.0). The metal
recovery ratios were 80:1, 60:1, and 27:1 for Cu, Cd, and Pb, respectively.
Moreover, with a pH gradient elution, the column-trapped metals can be optimally
recovered at distinct pH values. Continuous biosorption of Pb, Cu, and Cu with
four columns in series was also conducted. Results from the multibed operation
demonstrate that Pb ions strongly inhibited the adsorption of Cu and Cd, which
only occurred initially, and subsequently, an essential portion of the adsorbed
Cu and Cd ions was replaced by Pb ions due to the ion exchange effect. However,
since Pb ions were rapidly removed from the bulk at the onset of metal loading,
Pb adsorption in columns 2-4 was negligible for the first 10-30 h, leading to an
elevation in the breakthrough time (tb) and the capacity for Cu and Cd in columns
2-4. A back-propagation neural network model was shown to be able to predict the
breakthrough curves of the three metals in the multicolumn processes with a
ternary-metal feed.
PMID- 9758662
TI - Extraction and activity of chymotrypsin using AOT-DOLPA mixed reversed micellar
systems.
AB - Novel reversed micellar solutions formulated with a mixture of AOT (dioctyl
sulfosuccinate) and DOLPA (dioleyl phosphoric acid) show good potential for use
in reversed micellar protein extraction operations. Chymotrypsin is easily
extracted from an aqueous phase into organic isooctane containing 10 mM AOT and
DOLPA in a 4:1 ratio. The extraction ability of the mixed reversed micelles of 10
mM was higher than that of 200 mM AOT alone. The results of extraction indicated
that the AOT-DOLPA mixed reversed micelles are very useful for separating and
enriching chymotrypsin. Back-extraction of chymotrypsin from the organic phase to
a fresh aqueous phase is also accomplished by adding an alcohol to the organic
phase. Although the back-transfer of chymotrypsin from the reversed micelles
formed by AOT alone is very slow and difficult, in the AOT-DOLPA mixed reversed
micelles, the back-extraction can be achieved completely by addition of 10% (v/v)
isobutyl alcohol to the reversed micellar phase. The time to attain to the
equilibrium of back-extraction was reduced from more than 24 to 2 h by adding the
alcohol. On the basis of the activity data, the best composition of AOT and DOLPA
was a 4:1 ratio and the total surfactant concentration was 10 mM. The activity of
chymotrypsin recovered from the mixed reversed micelles was higher than that of
the initial protein before the forward-transfer. This result means that the novel
mixed reversed micellar solutions are useful not only in separation but also in
purification of proteins.
PMID- 9758665
TI - Effect of hydrodynamic and magnetic stabilization on fluidized-Bed adsorption
AB - Direct fermentation broth processing using fluidized beds is extremely
advantageous due to the low operating pressure drop of the device and the ability
of the bed to process suspended-solids-containing solutions. Unfortunately, the
solid particles in fluidized beds typically show a great deal of mixing compared
to those in packed beds. This mixing may lead to early breakthrough and
inefficient use of adsorptive capacity. Stabilization reduces the solids mixing
and improves the performance and efficiency of a fluidized bed. A comparison of
packed, fluidized, and stabilized beds reveals that, while normal fluidized beds
do contain a significant amount of mixing, the breakthrough behavior of the bed
is not drastically different than that of a packed bed. Magnetic stabilization of
the bed usually leads to an increase in adsorption efficiency but is dependent on
field strength and orientation. Permanently magnetized beds were also
investigated and produced breakthrough efficiencies similar to those of packed
beds.
PMID- 9758666
TI - The behavior of hydrocolloid coatings on vegetative materials
AB - Coating vegetative materials by gelling agents is a process characterized by four
different time scales. After wetting and penetration of the vegetative skin by
the gum solution, adhesion of the viscous solution to the outer layer (skin) of
the coated material is possible. The gelled film (coating) collapses during
further drying and adheres to the vegetative tissue. Critical surface tensions of
the solid object to be coated, its apparent and real roughness, wettability of
the surfaces by the gum solution, the composition and polarity of the films
designed to coat the solid, and the surface tension of gum coating solutions are
among the critical properties that need to be explored and changed for a
successful coating process. The critical surface tensions of garlic peel and
gellan and alginate films (coatings) were evaluated by Zisman plots. Garlic skin
has a low surface tension compared with those of synthetic films such as
polystyrene and polyethylene. A spreading technique was used to determine the
surface tension of the dry film and the solid garlic skin. Surface tension was
divided into dispersive and polar components. The similarity between the coating
solution and the object to be coated in values of dispersive and polar components
influences the spreadability of the coating gum solutions. Better compatibility
between the coated object and the coating films can be achieved by incorporating
surface-active agents within the coating gum solution. From the compatibility
requirements detailed above, it can be concluded that tailor-made hydrocolloid
coatings for different vegetative materials can only be achieved by further
exploring the chemical and physical properties of the coating solutions and the
coated objects.
PMID- 9758667
TI - Microscopy of DNA in dilute polymer solutions.
AB - The mechanism of separation of DNA in polymer solutions is not well understood.
In this paper we use epifluorescence videomicroscopy to investigate the dynamic
behavior of DNA electrophoresing through dilute polymer solutions. DNA collides
with polymer obstacles, which cause the conformation of DNA to change from the
globular, random coil conformation it takes in free solution. There are two main
types of DNA-polymer collisions: U-shape collisions and brief collisions. In U
shape collisions, the DNA collides with a polymer obstacle, extends into a U
shape, and then slides around the polymer obstacle like a pulley. There are
occasionally multiple entanglement points, causing the DNA to take more complex
conformations, such as W-shapes. In the brief collision process, the DNA collides
with a polymer obstacle and begins to extend but then collapses back into its
globular conformation before a full U-shape is formed. The frequency of these
interactions increases as the DNA size increases, and it also increases when the
polymer size or concentration increases. These data support the transient
entanglement coupling mechanism of separation of DNA, which states that
entanglements between DNA and polymer molecules result in the separation of DNA.
PMID- 9758668
TI - Pressure-induced dissociation of antigen-antibody complexes.
AB - Pressures on the order of 1000-4000 bar have been reported to reversibly
dissociate a number of oligomeric protein complexes without gross changes in
protein structure. Here, we report that hydrostatic pressure can also dissociate
some antigen-antibody complexes in solution. The association of fluorescent
labeled antigens with monoclonal antibodies was monitored via increases in the
fluorescence anisotropy upon binding. Previously, we had found that pressures of
2000 atm were able to dissociate bovine serum albumin (BSA) from immunoadsorbents
formed from certain antibodies but not others. In this study, we have found that
the sensitivity to pressure in solution is present for the interaction of BSA
with MAb 9.1 and absent for the interaction of BSA with MAb 6.1; this behavior is
consistent with the immunoadsorbent study. The interaction of hen egg white
lysozyme with two monoclonal antibodies was also measured. Interestingly, the
complex with the greater electrostatic character (HyHEL-5) did not exhibit
pressure sensitivity, as would be expected due to electrostriction effects,
whereas the more hydrophobic complex (HyHEL-10) exhibited a strong pressure
sensitivity. In each of the systems displaying pressure sensitivity, the free
energy of association was found to increase linearly with pressure, indicating a
constant change in volume between the free and bound states. Overall, these
results indicate that some antigen-antibody complexes exhibit significant
sensitivity to pressure, whereas others do not; the mechanisms that discriminate
between these cases remain unresolved. Understanding and manipulation of this
phenomenon may prove useful in a variety of processes involving the recovery from
antigens of antibodies.
PMID- 9758669
TI - Single- and dual-fractal analysis of hybridization binding kinetics: biosensor
applications.
AB - The diffusion-limited hybridization kinetics of analyte in solution to a receptor
immobilized on a biosensor or immunosensor surface is analyzed within a fractal
framework. The data may be analyzed by a single- or a dual-fractal analysis. This
was indicated by the regression analysis provided by Sigmaplot. It is of interest
to note that the binding rate coefficient and the fractal dimension both exhibit
changes in the same direction for both the single-fractal and the dual-fractal
analysis examples presented. For example, for a single-fractal analysis and for
the hybridization of 10 nM 16CFl (oligonucleotide) to 16B immobilized via
sulfosuccinimidyl-6-(biotinamido)hexanoate and streptavidin using chemical and
thermal regeneration (Abel, A. P.; Weller, M. G.; Duveneck, G. L.; Ehrat, M.
Widmer, H. M. Anal. Chem. 1996, 68, 2905-2912), an increase in the fractal
dimension, Df from 1.211 (chemical regeneration) to 1.394 (thermal regeneration),
leads to an increase in the binding rate coefficient, k, from 86.53 (chemical
regeneration) to 100.0 (thermal regeneration). An increase in the degree of
heterogeneity on the biosensor surface leads to an increase in the binding rate
coefficient. When a dual-fractal analysis was utilized, an increase in the
fractal dimension value from Df1 to Df2 leads to an increase in the binding rate
coefficient value from k1 to k2. The fractional order of dependence of the
binding rate coefficient, k1, on (a) the analyte (rRNA) concentration in solution
and (b) on the fractal dimension, Df1, for the hybridization kinetics to detect
Listeria species (Fliss, R.; St-Laurent, M.; Emond, E.; Simard, R. E.; Lemieux,
R.; Ettriki, A.; Pandian, S. Appl. Microbiol. Biotechnol. 1995, 43, 717-724.)
further reinforces the fractal nature of the system. The binding rate
coefficient(s) expressions developed as a function of the analyte concentration
in solution and the fractal dimension are of particular value since they provide
a means to better control of biosensor or immunosensor performance.
PMID- 9758671
TI - Intermittent light irradiation with a second-scale interval enhances caffeine
production by coffea arabica cells
AB - We developed novel equipment that intermittently illuminates Coffea arabica cell
suspensions at a second-scale interval and investigated how intermittent
irradiation enhances caffeine biosynthesis by C. arabica cells. The light/dark
cycles consisting of 2 s of illumination and 18 s of darkness enhanced caffeine
production, reaching the same level as for continuous light. The intermittent
illumination increased the production efficiency regarding light consumption by a
factor of 10. Caffeine production was determined by light intensity regardless of
intermittent or continuous light irradiation. We propose a new concept for
designing a photobioreactor that is applicable to secondary metabolite production
by plant cell culture.
PMID- 9758670
TI - Modified electrodes with synthetic biocatalytic membranes.
AB - A biocatalytic membrane based on an immobilized enzyme molecule has been
prepared. Oxidative electropolymerization of 8-hydroxyquinaldine (8-OHQ) monomers
in 0.2 M, pH 7 phosphate buffer containing glucose oxidase (GOx) has been carried
out to modify the surfaces of GC, Au, and Pt rotating disk electrodes. The
biocatalytic properties of the synthesized membrane were characterized by
studying the catalytic activities of the immobilized GOx. Signals obtained from
modified GC electrodes with this biomembrane were mainly attributed to the
immobilized GOx. Signals obtained from modified Pt or Au electrodes were due to
the combined contribution of the enzyme and the native electrode's material. The
potential analytical applications of these modified electrodes as
bioelectrochemical sensors were also investigated.
PMID- 9758672
TI - Acetic acid production from fructose by clostridium formicoaceticum immobilized
in a fibrous-Bed bioreactor
AB - The fermentation kinetics of acetic acid production from fructose by Clostridium
formicoaceticum was studied at pH 7.6 and 37 degreesC. Recycle batch, fed-batch,
and continuous fermentations using immobilized cells in a fibrous-bed bioreactor
were studied for their potential application in producing acetic acid from
fructose, a fermentable sugar commonly found in corn steep liquor and many other
food processing wastes. For the immobilized cell fermentation, acetic acid yield
from fructose was approximately 1.0 g/g, with a final acetate concentration of
approximately 78 g/L and the overall reactor productivity (based on the fibrous
bed bioreactor volume) of approximately 0.95 g/(L.h) in the fed-batch
fermentation. For a similar fed-batch fermentation with free cells, acetic acid
yield was approximately 0.9 g/g, the highest final acetate concentration was
approximately 46 g/L, and the overall productivity was approximately 0.12
g/(L.h). In the continuous fermentation with immobilized cells, the reactor
productivity decreased from 3.2 to 1. 3 g/(L.h) as retention time increased from
16 to 72 h to reach 100% conversion. Compared to free-cell fermentations, the
superior performance of the fibrous-bed bioreactor can be attributed to the high
density (>30 g/L) of viable cells immobilized in the fibrous bed. The
fermentation product, acetic acid, was found to be a noncompetitive inhibitor to
the cells. However, the immobilized cells had a higher maximum production rate
(pmax) and a higher value for the inhibition rate constant (Kp) than those for
the free cells, suggesting that the immobilized cells in the fibrous-bed
bioreactor were less sensitive to acetic acid inhibition than the free cells.
This improvement in kinetic behaviors for immobilized cells confirms that the
fibrous-bed bioreactor can be used as an effective tool for adapting and
screening for acetate-tolerant strains.
PMID- 9758673
TI - Application of logistic growth model to pharmacodynamic analysis of in vitro
bactericidal kinetics.
AB - A new pharmacodynamic model for the analysis of in vitro bactericidal kinetics
was developed based on the logistic growth model, with the bacterial phases
divided into two compartments. The model equations are expressed as nonlinear
simultaneous differential equations, and the Runge-Kutta-Gill method was adopted
to numerically solve the equations in both the simulation and the least squares
curve-fitting procedures. The model can describe the initial killing and the
regrowth phases and can explain the nonlinear dependence of the killing rate on
the drug concentration. The model can also explain the plateau in the bacterial
growth curve that is often observed in in vitro experiments. The model was
applied to analysis of the in vitro time-killing data of beta-lactam antibiotics,
S-4661, meropenem, imipenem, cefpirome, and ceftazidim against three types of
bacteria, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.
The results of curve-fitting using the least squares program MULTI (Runge) showed
good fits for all types of drugs and bacteria. The relationship between the
characteristics of the drug-bacteria interactions and the estimated
pharmacodynamic parameters is discussed.
PMID- 9758674
TI - Inhibition of desipramine hydroxylation (Cytochrome P450-2D6) in vitro by
quinidine and by viral protease inhibitors: relation to drug interactions in
vivo.
AB - Pharmacokinetic drug interactions with viral protease inhibitors are of potential
clinical importance. An in vitro model was applied to the quantitative
identification of possible interactions of protease inhibitors with substrates of
cytochrome P450-2D6. Biotransformation of desipramine (DMI) to hydroxydesipramine
(OH-DMI), an index reaction used to profile activity of human cytochrome P450
2D6, was studied in vitro using human liver microsomes. Quinidine and four viral
protease inhibitors currently used to treat human immunodeficiency virus
infection were tested as chemical inhibitors in this system. Formation of OH-DMI
from DMI was consistent with Michaelis-Menten kinetics, having a mean Km value of
11.7 microM (range: 9.9-15.3 microM). Quinidine, a highly potent and relatively
selective inhibitor of P450-2D6, strongly inhibited OH-DMI formation with an
apparent competitive mechanism, having a mean inhibition constant of 0.16 microM
(range: 0.13-0.18 microM). All four protease inhibitors impaired OH-DMI
formation; the pattern was consistent with a mixed competitive-noncompetitive
mechanism. Mean inhibition constants (small numbers indicating greater inhibiting
potency) were as follows: ritonavir, 4.8 microM; indinavir, 15.6 microM;
saquinavir, 24.0 microM; nelfinavir, 51.9 microM. In a clinical pharmacokinetic
study, coadministration of ritonavir with DMI inhibited DMI clearance by an
average of 59%. The in vitro findings, together with observed plasma ritonavir
concentrations, provided a reasonable quantitative forecast of this interaction,
whereas estimated unbound plasma or intrahepatic ritonavir concentrations yielded
poor quantitative forecasts. Thus the in vitro model correctly identifies
ritonavir as a potent and clinically important inhibitor of human P450-2D6. Other
protease inhibitors may also inhibit 2D6 activity in humans, but with lower
potency than ritonavir.
PMID- 9758675
TI - Evaluation of pluronic F127-based sustained-release ocular delivery systems for
pilocarpine using the albino rabbit eye model.
AB - The overall objective of this study was to develop Pluronic F127 (PF127)
containing formulations of pilocarpine hydrochloride (PHCL) which can be used for
sustained-release ocular delivery of PHCL. The PF127 formulations of PHCL
containing methylcellulose (MC) or hydroxypropyl methylcellulose (HPMC) as an
additive had previously exhibited the slowest dissolution rates and released the
drug the slowest in vitro. This study was performed to assess the in vivo
performance of these two formulations using miosis in the albino rabbit eye
produced by PHCL as a measure of ocular bioavailability. The PF127MC formulation
(20 microL) had a significantly greater intensity of miosis compared to the same
volume of an isotonic solution of PHCL. The duration and the intensity of the
miotic response increased significantly as the instilled volume of the PF127MC
gel formulation increased. The miotic response, expressed as % bioactivity by
assigning a value of 100% to the 20 microL PF127MC treatment, was increased as
the volume instilled was reduced from 60 to 20 microL. However, no difference in
bioactivity between the 60 and 100 microL volumes was observed. In addition, the
100 microL volumes of both the PF127MC and PF127HPMC gel formulations exhibited
bioactivity equivalent to 20 microL of an isotonic PHCL solution. Thus, for a
given instilled concentration, the larger the volume instilled the greater the
amount of drug present in tear fluid and thus the higher the concentration
delivered to the iris sphincter muscle and hence the greater the miotic response.
However, the fraction of the dose reaching the iris sphincter muscle was greater
for the smaller instilled volume. On the basis of these findings and previous in
vitro results, the PF127 formulations of PHCL having MC or HPMC as an additive
showed considerable potential as sustained-release ocular delivery systems for
PHCL. This conclusion was based upon their ability to provide a substantial
prolongation of drug action and an improvement in the ocular bioavailability of
pilocarpine compared to conventional eye drops and previously utilized PF127
formulations of PHCL. It appears that ocular bioavailability can be increased
more readily by altering both the rheological characteristics of the delivery
system and by using a smaller dose volume.
PMID- 9758676
TI - Enhanced colonic and rectal absorption of insulin using a multiple emulsion
containing eicosapentaenoic acid and docosahexaenoic acid.
AB - The aim of this study was to test the effects of eicosapentaenoic acid (EPA) and
docosahexaenoic acid (DHA) on insulin absorption from rat intestinal loops in
situ, using a water-in-oil-in-water (W/O/W) multiple emulsion. The enhancement
effect of these long-chain polyunsaturated fatty acids was compared with that of
free fatty acids having a C18 alkyl chain. The emulsion (insulin dose, 50
units/kg) was administered directly into the colonic and rectal loops. Both EPA
and DHA strongly enhanced insulin absorption and induced hypoglycemia after
colonic and rectal dosing. Comparing the pharmacological availability, the order
of effectiveness with respect to the enhanced absorption of insulin was DHA >/=
EPA > C18 unsaturated fatty acids >> C18 saturated fatty acid at both sites. DHA
showed greater effects upon rectal dosing than upon colonic dosing. Histological
studies revealed that the emulsion incorporating DHA did not induce gross
morphological changes in the structure of the intestinal mucosa. Our results
indicate that a W/O/W multiple emulsion incorporating DHA is a possible means of
facilitating the intestinal absorption of insulin without inducing any serious
damage to the epithelial cells.
PMID- 9758677
TI - Palmitoyl derivatives of interferon alpha: potential for cutaneous delivery.
AB - Palmitoyl derivatives of interferon alpha2b (p-IFNalpha) were prepared by
covalent attachment of the fatty acid to lysine residues in the protein through a
reaction with N-hydroxysuccinimide palmitate ester. The p-IFNalpha was
characterized by capillary electrophoresis (CE), mass spectrometry (MS), SDS
PAGE, and antiviral assay. Flow-through diffusion cells and human breast skins
were used to measure cutaneous and percutaneous absorption. Formation of p
IFNalpha derivatives was demonstrated by CE to be dependent on reaction time and
reagent: protein ratio. Electrospray MS of the crude p-IFNalpha mixture indicated
three populations of IFNalpha derivatives with 10, 11, and 12 palmitoyl
substitutions. The addition of palmitoyl residues to IFNalpha under the
conditions described reduced the antiviral specific activity by 50%. However, the
cutaneous absorption of p-IFNalpha was about 5-6 times greater than the parent
protein. The amount of p-IFNalpha and IFN alpha in whole skin after 24 h of
treatment was 2.106 +/- 1.216 microg/cm2 and 0.407 +/- 0.108 microg/cm2,
respectively. Approximately two times higher flux was detected for p-IFNalpha
compared to the nonfatty acylated IFNalpha. The total amount of drug diffused in
24 h was also approximately two times higher for the p-IFNalpha. The results
indicate a potential for using fatty acylated derivatives of IFN alpha for dermal
and transdermal delivery.
PMID- 9758678
TI - Site-specific drug delivery in the dog using flexible fiberoptic endoscopy.
AB - The development of a nonsurgical repeatable method of site-specific delivery to
the gastrointestinal tract in the canine is described. Studies to characterize
and validate this method were performed utilizing propranolol and etodolac due to
their well-known pharmacokinetic properties. Using a catheter placed through the
auxiliary port of a flexible fiberoptic endoscope, liquid dosage formulations
were consistently delivered to the canine stomach, duodenum, ileum, and colon. It
was shown that differences in site-specific delivery could be demonstrated with
this model. Propranolol tended to have the highest exposure following dosing to
the ileum as compared to other sites. The anesthetic regimen used to perform
endoscopy affected certain pharmacokinetic parameters of the compounds being
tested including decreasing the intrinsic clearance of propranolol. However,
since decreased intrinsic clearance should similarly affect AUCo regardless of
the site of delivery, this does not preclude site-specific comparisons to be
made. Further, no evidence has been reported for the effect of anesthesia on one
GI segment but not another. Thus for other compounds, assuming there are either
no anesthetic effects on intestinal pharmacokinetic parameters (absorption,
intestinal metabolism, etc.) or that they are consistent and uniform throughout
the intestinal tract, this model allows comparisons of the exposure following
delivery to differing intestinal sites.
PMID- 9758680
TI - Enhanced transdermal delivery of sex hormones in swine with a novel topical
aerosol.
AB - This study investigated the enhanced transdermal delivery of testosterone (Tes)
and estradiol (E2) in swine in vivo with novel metered-dose topical aerosols
containing the penetration enhancer padimate O (PadO) and predicted the dose
deliverable in humans from the calculated drug flux across the skin. Weanling
swine were catheterized and castrated under general anaesthesia and used as a
conscious hypogonadal model. Tes and E2 (with and without PadO) were applied
once, and venous blood samples were taken over 24 h. Tes and E2 plasma levels
were determined by radioimmunoassay. After daily topical dosing of Tes for 6
days, the plasma Tes levels were determined and the transdermal flux was
calculated by correcting the pseudo steady-state plasma concentration versus time
profile with the clearance of an iv dose within the same swine. After a single
application of the E2 aerosol over 30 cm2, or the Tes aerosol over 180 cm2, the
mean AUC0-24 h when PadO was included in the spray was 14.1- and 2.0-fold greater
than control, respectively (p < 0.03). After the sixth application of the Tes
spray with PadO, the mean flux (+/-SE, n = 4) across swine skin in vivo was 2.12
+/- 0.35 microg/cm2.h, which gave a predicted flux in humans of 0.95
microg/cm2.h. From these data the expected plasma levels of Tes in hypogonadal
men would compare well with the normal diurnal Tes profile in healthy men. These
novel topical aerosols are capable of enhanced transdermal delivery of sex
hormones in vivo, and they have the potential to deliver clinically relevant
doses to humans.
PMID- 9758679
TI - Enhanced skin permeation of sex hormones with novel topical spray vehicles.
AB - The feasibility of using some novel topical spray vehicles for enhanced
transdermal delivery of the sex hormones, testosterone (Tes), estradiol (E2),
progesterone (Prog), and norethindrone acetate (NA) has been investigated. The
new penetration enhancers, padimate O (PadO) and octyl salicylate (OSal) were
used and compared with laurocapram (AZ) and oleic acid (OA). A finite dose (5
microL/cm2) of each vehicle was applied to either shed snake skin or swine skin
in vitro, and the amount penetrated was measured with flow-through diffusion
cells. Partitioning into swine skin was determined after an exposure time of 1
min. Rapid partitioning of Tes and PadO into swine skin occurred after 1 min with
70% and 60% of the applied dose, respectively, remaining in the skin after the
unabsorbed dose was removed by rinsing with absolute ethanol. The cumulative
amount at 24 h (Q24 h) of Tes penetrating across the snake skin was significantly
enhanced (p < 0.05) up to 6-fold for OSal, 3-fold for OA and AZ, and 2-fold for
PadO compared to control. Using PadO or AZ, the Q24 h ranged from three- to
thirteen-fold over control (p < 0.05) for E2, Prog, and NA. Extrapolation of
these data to predict what would happen in humans suggests that it should be
possible to deliver clinically relevant amounts of sex hormones in this manner
with once daily dosing.
PMID- 9758681
TI - Transdermal delivery of estradiol in postmenopausal women with a novel topical
aerosol.
AB - The objective of this study was to determine if a novel metered-dose topical
aerosol (MDTA) formulation containing the new dermal penetration enhancer,
padimate O, could enhance the transdermal delivery of estradiol to an extent that
would result in clinically relevant plasma concentrations. The estradiol MDTA
(with padimate O) was applied once daily at 0800 h to postmenopausal women for 9
days, and plasma estradiol and estrone was measured daily (24 h postapplication)
by radioimmunoassay. The topical dose was administered as three 1 mg doses of
estradiol, each applied as a single spray over 10 cm2 which were placed adjacent
to each other on the subject's ventral forearm. None of the subjects tested
showed any sign of skin irritation at the application site over the entire study
period using the Draize irritation score. In four postmenopausal women (age 54-63
years, weight 67-93 kg) the mean estradiol level 24 h postapplication over the 9
day study period was 53 pg/mL. This result was significantly greater (p < 0.001)
than the baseline value of 13 pg/mL. The mean estradiol/estrone ratio also rose
significantly (p < 0.04) from a baseline value of 0.2 up to 0.8. We conclude that
this novel MDTA formulation significantly enhances the transdermal delivery of
estradiol to allow a clinically relevant dose of estradiol to be delivered in
postmenopausal women with once daily dosing.
PMID- 9758683
TI - Some relationships between the physical properties of various 3-acyloxymethyl
prodrugs of phenytoin to structure: potential in vivo performance implications.
AB - Physicochemical properties of neutral N-acyloxyalkyl derivatives of phenytoin in
aqueous, organic solvents and simulated intestinal fluid were evaluated. Based on
the hypothesis that these low melting prodrugs may have improved physical
properties such as solubility and dissolution rate in gastrointestinal fluid, an
enhanced bioavailability of these prodrugs may be observed relative to phenytoin.
Melting points, aqueous solubilities, and octanol-water (Poct) and cylcohexane
water (Pcyc) partition coefficients of phenytoin and its prodrugs were
determined. A simulated intestinal bile salts-lecithin mixture (SIBLM) was also
prepared to possibly mimic the intestinal fluid content. Solubility and
dissolution rates of phenytoin and its prodrugs were conducted in aqueous buffer
and SIBLM. Apparent micelle-water partition coefficients (Kapp) were calculated
by using the aqueous and SIBLM equilibrium solubility data. These properties were
qualitatively or quantitatively correlated to the alkyl chain length of the
prodrugs. The melting points and aqueous solubilities of all the prodrugs were
lower than that of the parent compound, phenytoin. The apparent micelle-water
partition coefficient increased with an increase in chain length but unlike the
octanol-water and cyclohexane-water partition coefficients the relationship was
complex. There was a disproportionate increase in the interaction between the
micelle and the prodrug with the prodrugs with alkyl groups larger than four
carbons. In SIBLM, the solubilities and dissolution rates were increased to a
greater extent for the prodrugs than that for phenytoin. The implications are
that the bioavailability of phenytoin from these prodrugs may be comparable to or
higher than that of phenytoin despite having lower aqueous solubilities,
especially after a meal inducing bile flow.
PMID- 9758682
TI - Arterial uptake of biodegradable nanoparticles: effect of surface modifications.
AB - Restenosis is the reobstruction of an artery following interventional procedures
such as balloon angioplasty or stenting. Local pharmacotherapeutic approaches
using controlled release systems are under investigation to inhibit the regional
pathophysiologic process of restenosis. We have been investigating biodegradable
nanoparticles (100 +/- 39 nm in diameter, mean +/- sd) for the local intra
arterial drug delivery. The purpose of this study was to investigate nanoparticle
surface modifications (see Table 1) to enhance their arterial uptake. The PLGA
(polylactic polyglycolic acid copolymer) nanoparticles were formulated by an oil
in-water emulsion solvent evaporation technique using a 2-aminochromone (U-86983,
Upjohn and Pharmacia) (U-86) as a model antiproliferative agent. The various
formulations of nanoparticles were evaluated for the arterial wall uptake by
using an ex-vivo dog femoral artery model. The selected formulations were then
tested in vivo in acute dog femoral artery and pig coronary artery models. The
nanoparticles surface modified with a cationic compound,
didodecyldimethylammonium bromide (DMAB), demonstrated 7-10-fold greater arterial
U-86 levels compared to the unmodified nanoparticles in different ex-vivo and in
vivo studies. The mean U-86 levels were 10.7 +/- 1.7 microg/10 mg (dog) and 6.6
+/- 0.6 microg/10 mg (pig) in the artery segments ( approximately 2 cm) which
were infused with the nanoparticles. The pig coronary studies further
demonstrated that the infusion of nanoparticles with higher U-86 loading reduced
the arterial U-86 levels, whereas increasing the nanoparticle concentration in
the infusion solutions increased the arterial U-86 levels. The biodistribution
studies in pigs following coronary arterial administration of nanoparticles
demonstrated disposition of U-86 in the myocardium and distally in the liver and
the lung. The mechanism of enhanced arterial uptake of the DMAB surface modified
nanoparticles seems to be due to the alteration in the nanoparticle surface
charge. The unmodified nanoparticles had a zeta potential of -27.8 +/- 0.5 mV
(mean +/- sem, n = 5), whereas the DMAB modified nanoparticles demonstrated a
zeta potential of +22.1 +/- 3.2 mV (mean +/- sem, n = 5). The adsorption of DMAB
to the nanoparticle surface followed the Freundlich isotherm with binding
capacity k = 28.1 microg/mg and affinity constant p = 2. 33. In conclusion,
surface modified nanoparticles have potential applications for intra-arterial
drug delivery to localize therapeutic agents in the arterial wall to inhibit
restenosis.
PMID- 9758684
TI - In vitro displacement by rat serum of adsorbed radiolabeled poloxamer and
poloxamine copolymers from model and biodegradable nanospheres.
AB - Poloxamer 407 and poloxamine 908 have been used by many research groups to modify
the surface of both model latex and biodegradable nanospheres, thereby producing
nanospheres that have shown reduced protein adsorption in vitro and extended
circulation times in vivo. A potential limitation of such systems is the
desorption of the copolymer coating layer. We describe a two-stage process to
radiolabel poloxamer 407 and poloxamine 908 that has facilitated an investigation
into this potential desorption, in vitro. The first stage of the labeling
procedure involved the substitution of the terminal hydroxyl groups in each
poly(ethylene oxide) (PEO) chain of poloxamer 407 and poloxamine 908 with an
amino group. The aminated copolymers were then radiolabeled with 125Iodine Bolton
Hunter reagent. The efficiency of labeling was calculated to be approximately 20%
for the tetramine poloxamine 908 and approximately 33% for the diamine poloxamer
407. Remaining free amino groups were then either acetylated, using acetic
anhydride, or left in the free amino form. Covalent linkage of the radiolabel to
the copolymer was confirmed by nuclear magnetic resonance (NMR) and infrared (IR)
spectroscopy. The stability of the link between radiolabel and copolymer to
hydrolysis was also confirmed; <4% loss of radiolabel occurred from poloxamine
908 after incubation in phosphate-buffered saline (PBS) at 37 degrees C for 8
days. The radiolabeled copolymers (with the free amino groups acetylated) were
then used in experiments that have given the first direct evidence that adsorbed
copolymers can be displaced by serum proteins in significant amounts from the
surface of model and biodegradable nanospheres. The displacement was highly
dependent on copolymer-nanosphere compatibility, with up to 78% of 125I tetramine
poloxamine 908 being displaced from poly(lactide-co-glycolide) (PLGA) nanospheres
in 24 h, compared with 20% displacement of 125I tetramine poloxamine 908 in 24 h
from polystyrene nanospheres. These results have direct implication for the
future design of drug delivery systems based on coated nanospheres.
PMID- 9758686
TI - A pharmacokinetic/pharmacodynamic comparison of SAAM II and PC/WinNonlin modeling
software.
AB - This paper presents a detailed comparison of the kinetic analysis software
packages SAAM II and PCNonlin/WinNonlin, based on benchmark modeling problems
reported in "Pharmacokinetic andPharmacodynamic Data Analysis: Concepts and
Applications" (Gabrielsson and Weiner, 1994) and seven additional models. For
each model, both software packages were presented with identical implementations.
Models were initially executed in PCNonlin or WinNonlin and automated comparisons
with SAAM II made using Microsoft Test. Models investigated included one- and
multicompartment models with nonlinearities, multiple inputs and samples,
multiple simultaneous experiments, and linear equations. Maximum number of
compartments, data sets, and parameters were 9, 5, and 10, respectively. We
compared 88 different models, many of them in different configurations, e.g.,
different weighting schemes or different parameter limits. The total number of
attempted comparisons between SAAM II and PCNonlin was 161, of which 142 executed
without problems. Parameter estimates, their precision (standard errors), and
model predictions were compared; a difference of 1% or less was considered
"agreement". Observed differences, mainly in parameter standard errors, can be
accounted for in terms of different optimization algorithms, convergence
criteria, and individual capabilities. In general, there was good agreement (<1%
difference) between SAAM II and PCNonlin in terms of parameter estimates and
model predictions. However, due to differences in the optimization procedure,
parameter standard errors showed considerable differences. Additionally, there
were differences when multiple data sets were fitted, indicating the importance
of different fitting procedures for interpreting multiple kinetic data sets. The
full results of the comparison and the model files in SAAM II and
PCNonlin/WinNonlin formats are available from the authors.
PMID- 9758685
TI - Partitioning and localization of spin-labeled amantadine in lipid bilayers: an
EPR study.
AB - EPR was used to study the distribution of the spin-labeled amantadine (AA-SL)
between the bulk hydrophobic-hydrocarbon solvent, light paraffin oil, and water
and between hydrophobic-hydrocarbon chain region of lipid membranes and water.
The AA-SL molecules were soluble in both hydrophobic and polar regions of
investigated systems. It was shown that the partition coefficient of AA-SL
between the hydrocarbon region of the L-alpha-dimyristoylphosphatidylcholine
fluid-phase membrane and water is much higher than between bulk hydrocarbon
solvent and water. Furthermore, the partitioning of AA-SL into membranes of
multilamellar liposomes made of L-alpha-dimyristoylphosphatidylcholine, L-alpha
dipalmitoylphosphatidylcholine, and L-alpha-distearoylphosphatidylcholine was
studied as a function of temperature, indicating no abrupt change at the main
phase transition of these membranes. It is also clear from our data that AA-SL
can penetrate into the gel-phase membrane practically with the same partitioning
as into the fluid-phase membrane. Furthermore, it was shown that at least part of
the AA-SL molecule is deeply buried in the hydrocarbon chain region of the
membrane.
PMID- 9758687
TI - A partial area difference analysis for estimat- ing elimination rate constants
and DistributionVolumes of metabolites
PMID- 9758688
TI - alpha4 and alpha5 integrins costimulate the CD3-dependent proliferation of fetal
thymocytes.
AB - Although integrin receptors have been shown to function as costimulatory
molecules on mature thymocytes and T cells, it is not known whether these
receptors can function as costimulatory molecules on immature thymocytes.
Previous studies have shown that the expression of alpha4 and alpha5 integrins
were significantly higher on immature, adult CD4(-)CD8(-) thymocytes than on
either mature thymocytes or T cells, suggesting that these receptors are involved
in early thymocyte development. In this study, we show that day 16 fetal
thymocytes express levels of alpha4 and alpha5 equivalent to those of adult CD4(
)CD8(-) thymocytes. Immobilized fibronectin, a ligand for alpha4 and alpha5
integrins, was found to enhance the CD3-dependent proliferation of these fetal
thymocytes. In the presence of IL-7, the magnitude of the proliferative response
increased with time of incubation, resulting in a dramatic increase in the
percentage of gammadelta thymocytes. The enhancement of proliferation by
fibronectin was abrogated by soluble antibodies against alpha4 and alpha5,
whereas immobilized mAb to alpha4 and alpha5 substituted for fibronectin in
enhancing CD3-dependent proliferation, demonstrating that alpha4 and alpha5
integrins were responsible for the enhanced proliferation by fibronectin. Anti
alpha4 mAb enhanced proliferation of fetal thymocytes by 100%, whereas anti
alpha5 mAb and anti-CD28 mAb enhanced proliferation by 25%. Other costimulatory
molecules, such as CD2, FcRgamma, and Thy-1, had no effect on the CD3-dependent
proliferation of day 16 fetal thymocytes. This study demonstrates that alpha4 and
alpha5 integrins are capable of costimulating fetal thymocytes.
PMID- 9758689
TI - Idiosyncratic alterations of TCR size distributions affecting both CD4 and CD8 T
cell subsets in aging mice.
AB - We have used a spectratyping method, which displays the size distribution for the
complementarity-determining region 3 (CDR3) for T cells utilizing a specific TCR
Vbeta gene, to examine the effects of aging on the TCR repertoire of (BALB/c x
C57BL/6)F1 hybrid mice. Although the size distributions from T cells of 8-month
old mice were typically symmetrically shaped around one or two bands of
intermediate size, spectratypes from mice 16 or 24 months of age were frequently
distorted, with specific size classes either over- or underrepresented compared
to normal young controls. Each of 12 mice tested at 16 or 24 months of age had a
skewed spectratype for at least one of the 24 Vbeta families examined, and some
mice had more than 50% of their spectratypes skewed significantly, as judged by a
chi2 test. Comparable age-associated skewing of the T cell repertoire occurred in
the CD4 and CD8 subsets, and every mouse over 16 months of age exhibited at least
one skewed Vbeta family in both the CD4 and CD8 populations. Although the mice
were genetically identical and raised in common facilities, their spectratype
patterns were nonetheless idiosyncratic: i.e., the specific set of abnormalities
was distinct for each individual old mouse. Whether these distortions of the TCR
repertoire in middle-aged and older mice lead to alterations in immune function
remains to be determined.
PMID- 9758690
TI - Activation of donor-specific CTL in a tolerant recipient of cardiac allograft.
AB - Permanent graft acceptance was induced with cyclosporine A in a low responder rat
strain combination PVG (RT1(c)) to DA (RT1(av1)) of cardiac transplants.
Challenge (alloimmunization) with donor and third-party WF (RT1(u)) cells was
performed and followed by the analysis of alloreactive cytotoxicity. The
cytotoxic T lymphocytes (CTL) from recipients with permanently accepted cardiac
grafts manifested cytolytic activity against third-party target cells but not
against donor target cells. The findings demonstrated unresponsiveness to be
donor-specific, i.e., transplant tolerance was present. This was verified by
retransplantation of the DA recipient with either a second PVG heart (which was
accepted) or a third-party (WF) heart (which was rejected). Restoration of donor
specific CTL after injection of exogeneous interleukin(IL)-2 concomitant with
challenge showed that the donor-specific CTL were not depleted, but unable to be
activated as a consequence of IL-2 deficiency. Despite donor-specific CTL
activation in vivo the recipients failed to reject their established grafts,
implying an ongoing presence of suppression.
PMID- 9758691
TI - Regulation of interleukin-12 production in human cells stimulated with
Mycobacterium bovis BCG.
AB - Interleukin 12 (IL-12) is a monokine which plays a critical role in resistance to
Mycobacterium tuberculosis infection. However, little is known about the
regulation of IL-12 production by human cells stimulated with BCG. Here we report
that in vitro infection of human mononuclear cells with M. bovis BCG induces the
release of IL-12 protein. We also observed that the ability of BCG to stimulate
release of IL-12 from human cells was significantly inhibited by IL-10. The
inhibitory effect of IL-10 on the secretion of IL-12 was specific, as it was
significantly abolished in the presence of anti-IL-10 neutralizing monoclonal
antibody. These results were further confirmed as anti-IL-10 antibodies markedly
increased the levels of IL-12, suggesting that BCG-induced IL-10, as well as
exogenous IL-10, can regulate IL-12 production by human cells stimulated with M.
bovis BCG. Interestingly, IFN-gamma production in response to BCG had no
significant increase by the addition of neutralizing antibodies to IL-10.
Moreover, anti-IL-12 antibodies markedly reduced the levels of IFN-gamma produced
by BCG-stimulated human cells and abrogated the capacity of anti-IL-10 to
increase BCG-induced IFN-gamma. These studies are the first to demonstrate a
regulatory effect on IL-12 production by human cells infected with M. bovis BCG
and at the same time suggest that IL-12 may play an essential role during the
human immune response to M. bovis BCG stimulation.
PMID- 9758692
TI - Endothelial antigen presentation: stimulation of previously activated but not
naive TCR-transgenic mouse T cells.
AB - In vitro experiments have shown that endothelial cells can function as antigen
presenting cells to CD4(+) T lymphocytes. The studies presented here address the
question of whether naive versus previously activated CD4(+) helper T cells
differ in their responses to endothelial antigen presentation. TCR-transgenic
mice were used as a source of naive T cells of defined antigen specificity. These
cells were stimulated in vitro with antigen and splenic antigen-presenting cells
to generate populations of T lymphocytes with a previously activated/memory
phenotype. Two different types of mouse endothelial cells were used as antigen
presenting cells, including the SVEC4-10 line derived from lymph node endothelium
and primary murine pulmonary microvascular endothelium. Monolayer cultures of
both types of endothelium were capable of antigen-dependent stimulation of
previously activated TCR-transgenic CD4(+) cells. In contrast, neither
endothelial type could activate naive CD4(+) T cells. When costimulatory signals
were provided in trans by the addition of MHC-mismatched mouse spleen cells,
activation of naive T cells by endothelial antigen presentation could be
demonstrated. The expression of ICAM-1 or VCAM-1 on the endothelial cells was not
sufficient to activate naive T cells. Furthermore, the mouse lung endothelium
constitutively expresses B7-1, and therefore, the inability of endothelium to
stimulate naive T cells could not be attributed to a lack of CD28-ligands. These
studies suggest that the potential role of endothelial antigen presentation in
immune responses is restricted to promoting responses by T cells which have
previously encountered antigen presented by other antigen-presenting cells.
PMID- 9758693
TI - Direct cellular interaction with activated CD4(+) T cells overcomes
hyporesponsiveness of B-cell chronic lymphocytic leukemia in vitro.
AB - The proliferative response of clonal B cells from patients with chronic
lymphocytic leukemia (B-CLL) is drastically reduced compared to normal B
lymphocytes stimulated via the B cell antigen receptor complex or by CD40
ligation. In the present study we demonstrate that hyporesponsiveness of CLL-B
cells can be overcome by stimulatory pathways mediated by activated CD4(+) T
cells. In contrast to CD40 ligation, costimulation with activated T cells
promotes a proliferative response in CLL-B cells identical to that in normal B
cells. Furthermore, coculture with activated T cells improved survival of CLL-B
cells in vitro. Differentiation of CLL-B cells into IgM producing cells was
promoted, as well. However, the capacity for IgM secretion remained impaired
compared to that of normal B cells. For T-cell-mediated B cell activation direct
cellular contact with activated T helper cells is absolutely required. Prevention
of CD40/CD40L interaction by CD40 antibody caused only partial inhibition of B
cell activation, suggesting that additional signals are involved in T-B cell
interaction. Whereas interruption of the ligand pairs CD11a/CD54, CD5/CD72,
CD27/CD70 had no influence, the addition of CD58 antibody completely inhibited B
cell activation by activated T cells. In costimulation with cellular signals the
presence of B-cell-tropic cytokines, such as IL-2 and IL-4, was required to
optimize B-CLL proliferation, as demonstrated by the use of neutralizing
antibodies. We conclude from these results that proliferative hyporesponsiveness
by CLL-B cells can be circumvented by antigen-nonspecific signals in addition to
CD40 which are mediated by direct contact with activated T helper cells.
PMID- 9758694
TI - Development of phagocytic function of cultured human monocytes is regulated by
cell surface IL-10.
AB - Monocytes differentiating in vitro into macrophages increase their capacity to
ingest particles via FcgammaR and CR3. Because human recombinant IL-10 is a
potent up-regulator of phagocytosis in human monocytes, we investigated whether
spontaneously produced IL-10 could be a signal for the modulation of phagocytosis
by cultured monocytes. We show here that culture of monocytes in the presence of
anti-IL-10 mAb completely abolished up-regulation of phagocytosis of both EIgG
and EIgMC3bi, suggesting a role for spontaneously produced IL-10 in the
modulation of phagocytosis by cultured human monocytes. The inhibition exerted by
anti-IL-10 mAb on the development of FcgammaR-mediated ingestion was dependent on
the concomitant inhibition of FcgammaRIII induction in cultured cells. On the
other hand, a similar down-regulation of CR3 expression was not involved in the
inhibitory effect exerted by anti-IL-10 mAb on the development of CR3-mediated
ingestion. Monocytes secreted detectable levels of IL-10 when cultured in medium
but the concentrations of IL-10 in the supernatants decreased with length of time
in culture, the decrease being completely reversed by anti-IL-10 mAb. In
addition, we showed that monocytes expressed immunoreactive IL-10 on their
surface and this expression increased during differentiation into macrophages.
Whether this IL-10 was bound to specific membrane receptors or it was an integral
membrane protein remains to be determined; however, this latter possibility is
consistent with our observations that IL-10 did not elute with acid treatment and
exogenous IL-10 did not increase surface staining of monocytes. Our data indicate
that human mononuclear phagocytes express IL-10 on their membrane and suggest
that this cytokine may represent an autocrine signal for the increased phagocytic
function observed during differentiation of monocytes into macrophages.
PMID- 9758695
TI - Early phosphorylation events induced by DPIV/CD26-specific inhibitors.
AB - Dipeptidyl peptidase IV (DPIV, CD26) is known to be involved in the regulation of
T lymphocyte and NK cell activation and proliferation in vitro. The molecular
events of lymphocyte activation mediated by this ectopeptidase as well as their
physiological ligands are only partly established. Particularly, the necessity of
catalytic dipeptidase activity for the costimulatory function of this molecule
has been controversial. Here we provide evidence for a direct involvement of
DPIV/CD26 in early phosphorylation mechanisms which are known to be essential in
the signal transduction cascade of human T lymphocytes. We have found that DPIV
specific inhibitors (Lys[Z(NO2)]-thiazolidide and -piperidide) are capable of
inducing intracellular tyrosine phosphorylation in resting human T cells. On the
other hand, both inhibitors decreased the PMA-induced tyrosine phosphorylation in
human T cells in a dose-dependent manner. Furthermore, a linkage between CD26 and
the tyrosine kinase p56(lck) was shown by inhibition of PMA-induced
hyperphosphorylation of p56(lck) by means of DPIV-specific inhibitors. The data
presented here suggest that the inhibition of DPIV enzymatic activity induces a
inhibitory signal transmitted by tyrosine kinases which leads to a block in a PMA
induced downstream pathway. These results support the assumption that DPIV/CD26
is directly involved in early processes of T cell activation via its enzymatic
activity.
PMID- 9758696
TI - The impact of variation in the number of CD8(+) T-cell precursors on the outcome
of virus infection.
AB - We investigated the role of varying the initial number of naive antiviral CTL
precursors on the dynamics of LCMV-DOCILE infection. C57BL/6 mice, exhibiting
LCMV-specific CTLp frequencies of about 50, are protected against virus
persistence over a range of infectious doses up to 10(4) pfu. With 10-fold higher
doses, a 100-fold increase in CTLp is required to restore virus control. With
doses above 10(6) pfu, elevation of the initial CTLp number leads only to lethal
immunopathology. Similarly, a 1000-fold increase in the number of initial naive
CTLp enhances the overall kinetics of virus elimination, but cannot limit early
virus spread within the first 48 h after low-dose infection (500 pfu). Increases
in initial naive virus-specific CTLp numbers are of limited benefit in antiviral
control. In addition to the number of virus-specific T cells, the time period
needed to reach cytolytic effector function is a limiting parameter.
PMID- 9758697
TI - Macrophages may activate or destroy T cells with which they form antigen- or
coreceptor-mediated cellular conjugates.
AB - The formation of antigen- or mitogen-mediated cellular conjugates with T cells
enables macrophages to trigger in T cells costimulatory signals and to facilitate
T cell clonal expansion and differentiation. The present study describes T cell
death as an alternative consequence of T cell interaction with macrophages.
Macrophages initiate the deletion of T cells which they target for conjugate
formation through CD4 coreceptors. After suboptimal engagement, the TCR mediates
a deletion program. Optimal TCR stimulation induces a rescue program which
overrides the deletion program induced by suboptimal antigen receptor ligation or
by coreceptor engagement. Evidence is presented suggesting that receptor
clustering favors the transmission of activation signals, whereas ligation of
nonclustered receptors facilitates T cell deletion.
PMID- 9758699
TI - MAP kinase inactivation is required only for G2-M phase transition in early
embryogenesis cell cycles of the starfishes Marthasterias glacialis and
Astropecten aranciacus.
AB - Downregulation of MAP kinase is a universal consequence of fertilization in the
animal kingdom. Here we show that oocytes of the starfishes Astropecten
aranciacus and Marthasterias glacialis complete meiotic maturation and form a
pronucleus when treated with 1-methyladenine and then complete DNA replication
and arrest at G2 if not fertilized. Release of G2 by fertilization or a variety
of parthenogenetic treatments is associated with inactivation of MAP kinase.
Prevention of MAP kinase inactivation by microinjection of Ste11-DeltaN, a
constitutively active budding yeast MAP kinase kinase kinase, arrests fertilized
eggs at G2 in either the first or the second mitotic cell cycle, in a dose
dependent manner. G1 arrest is never observed. Conversely, inactivation of MAP
kinase by microinjection of the MAP kinase-specific phosphatase Pyst-1 releases
mature starfish oocytes from G2 arrest. The role of MAP kinase in arresting cell
cycle at various stages in oocytes of different animal species is discussed.
PMID- 9758700
TI - The relationship between rhombomeres and vestibular neuron populations as
assessed in quail-chicken chimeras.
AB - The aim of this study was to evaluate the role segmentation plays in the
determination of neuronal identity in the hindbrain. We focused on two specific
sets of hindbrain neurons, namely, the vestibulospinal and vestibulo-ocular
neurons, which comprise distinct groups that can be identified and distinguished
by virtue of their axonal projection pathways. The relationship between
rhombomeres and the vestibular neuron groups was assessed by a combination of
quail-chicken chimeric grafting and selective retrograde axonal tracing.
Individual quail hemirhombomeres were transplanted homotopically and
isochronically into a chicken embryo host. Subsequently, vestibulospinal and
vestibulo-ocular neurons with specific axon trajectories were labeled
retrogradely with biotin-conjugated dextran-amines. The relationship between the
spatial domains of the vestibular neuron groups and rhombomere-derived domains
had the following features: (1) some groups were derived from single rhombomeres;
(2) some groups were derived from multiple contiguous rhombomeres; (3) two groups
occupied domains that could not be defined in terms of whole rhombomere lengths;
(4) some groups spanning multiple rhombomeres exhibited an internal
cytoarchitectonic organization that related to individual rhombomeres; and (5)
some groups exhibited limited boundary violation. These results support the
notion that positional information within defined domains of the neural tube
provides a groundplan for the regional determination of neuronal identity and
axon pathfinding, and that hindbrain segmentation contributes to this process.
But they also indicate that segmentation is not the only mechanism that defines
the rostrocaudal domains of neuron types. Moreover, they emphasize that the
relationship between rhombomeres and neuronal determination cannot be couched
simply in terms of segmental iteration or of bimeric (paired rule) specification.
PMID- 9758701
TI - The alpha4 subunit of integrin is important for neural crest cell migration.
AB - We identify the alpha4 subunit of integrin as a predominant integrin expressed by
neural crest cells in both avian and murine embryos. Using degenerate primers, we
obtained a PCR fragment of the chick integrin alpha4 subunit that was
subsequently used to clone the full-length subunit with a predicted amino acid
sequence 60% identical to human and mouse alpha4 subunits. In situ hybridization
demonstrates that chick integrin alpha4 mRNA is expressed at high levels by
migrating neural crest cells and neural crest-derived ganglia at both cranial and
trunk levels. An antibody against the murine alpha4 subunit revealed similar
distribution patterns in mouse to chick. In addition to neural crest cells, the
integrin alpha4 subunit was later observed on the muscle masses of the limb, the
apical ectodermal ridge, and the developing liver. To examine the functional role
of the integrin alpha4 subunit in neural crest cell migration, we used an explant
preparation that allows visualization of neural crest cells in their normal
environment with or without perturbing reagents. In the presence of a blocking
antibody against the mouse integrin alpha4 subunit, there was a profound
abrogation of neural crest cell migration at trunk and hindbrain levels. Both the
numbers of migrating neural crest cells and the total distance traversed were
markedly reduced. Similarly, avian embryos injected with synthetic peptides that
contain the integrin alpha4 binding site in fibronectin displayed abnormal neural
crest cell migration. Our results suggest that the integrin alpha4 subunit is
important for normal neural crest cell migration and may be one of the primary
alpha subunits used for neural crest cell migration in vivo. Furthermore, the
integrin alpha4 subunit represents a useful neural crest marker in the mouse.
PMID- 9758702
TI - Roles of transforming growth factor-alpha and epidermal growth factor in chick
limb development.
AB - We have examined the distribution of transforming growth factor-alpha (TGF
alpha), epidermal growth factor (EGF), and the chicken EGF receptor (c-erbB), in
embryonic chick limbs. Prior to limb budding, TGF-alpha is present in prospective
limb-forming mesoderm and in prospective apical ectodermal ridge (AER)-forming
ectoderm, but is not detected in non-limb-forming flank mesoderm or ectoderm, nor
in presumptive non-AER-forming limb ectoderm, suggesting possible roles in
initial limb formation and AER induction. Consistent with this possibility, TGF
alpha is present in the mesoderm of the wing buds of the amelic chick mutants
limbless and wingless, which form and bud normally, but is absent from limbless
and wingless ectoderm, which fails to form an AER. TGF-alpha and EGF are present
in the AER of the developing limb, and TGF-alpha, EGF, and c-erbB are present in
the underlying subridge mesoderm, suggesting possible roles in reciprocal
AER/subridge mesoderm interactions required for limb outgrowth. We found that
exogenous TGF-alpha and EGF can promote the outgrowth of limb mesoderm in the
absence of the AER in vitro and can also promote the outgrowth of limbless and
wingless wing bud explants. EGF is present in ventral but not dorsal limb
ectoderm, suggesting a role for EGF in specification of ventral ectoderm. TGF
alpha and EGF are not detected in the differentiating cartilaginous elements or
muscle primordia of the limb, suggesting that cessation of TGF-alpha and EGF
expression may be required for cartilage and muscle formation. We have found that
exogenous TGF-alpha and EGF inhibit chondrogenesis and myogenesis of limb
mesenchyme in vitro. Together these results indicate that signaling through the
EGF receptor via endogenous TGF-alpha and EGF may be important for initial limb
formation, AER induction, outgrowth of limb mesoderm, and regulation of limb
chondrogenic and myogenic differentiation.
PMID- 9758703
TI - The Cspg2 gene, disrupted in the hdf mutant, is required for right cardiac
chamber and endocardial cushion formation.
AB - The heart defect (hdf) mouse is a recessive lethal that arose from a transgene
insertional mutation on chromosome 13. Embryos homozygous for the transgene die
in utero by embryonic day 10.5 postcoitus and exhibit specific defects along the
anterior-posterior cardiac axis. The future right ventricle and conus/truncus of
the single heart tube fail to form and the endocardial cushions in the
atrioventricular and conus/truncus regions are absent. Because the hdf mouse
mutation provided the opportunity to identify a gene required for endocardial
cushion formation and for specification or maintenance of the anterior most
segments of the heart, we initiated studies to further characterize the
phenotype, clone the insertion site, and identify the gene disrupted. Chromosome
mapping studies first identified the gene, Cspg2 (versican), as a candidate hdf
gene. In addition, an antibody recognizing a glycosaminoglycan epitope on
versican was found to be positive by immunohistochemistry in the extracellular
matrix of normal wild-type embryonic hearts, but absent in homozygous hearts.
Expression analysis of the Cspg2 gene showed that the 6/8, 6/9, and 7/9 Cspg2
exon boundaries were present in mRNA of normal wild-type embryonic hearts but
absent in the homozygous mutant embryos. DNA sequence flanking the transgene was
used to isolate from a normal mouse library overlapping genomic DNA segments that
span the transgene insertion site. The contiguous genomic DNA segment was found
to contain exon 7 of the Cspg2 in a position 3' to the transgene insertion site.
These four separate lines of evidence support the hypothesis that Cspg2 is the
gene disrupted by the transgene insertion in the hdf mouse line. The findings of
this study and our previous studies of the hdf insertional mutant mouse have
shown that normal expression of the Cspg2 gene is required for the successful
development of the endocardial cushion swellings and the embryonic heart segments
that give rise to the right ventricle and conus/truncus in the outlet of the
looped heart.
PMID- 9758704
TI - A single rostrocaudal colonization of the rodent intestine by enteric neuron
precursors is revealed by the expression of Phox2b, Ret, and p75 and by explants
grown under the kidney capsule or in organ culture.
AB - The colonization of the rodent gastrointestinal tract by enteric neuron
precursors is controversial due to the lack of specific cellular markers at early
stages. The transcription factor, Phox2b, is expressed by enteric neuron
precursors (Pattyn et al. Development 124, 4065-4075, 1997). In this study, we
have used an antiserum to Phox2b to characterize in detail the spatiotemporal
expression of Phox2b in the gastrointestinal tract of adult mice and embryonic
mice and rats. In adult mice, all enteric neurons (labeled with neuron-specific
enolase antibodies), and a subpopulation of glial cells (labeled with GFAP
antibodies), showed immunoreactivity to Phox2b. In embryonic mice, the appearance
of Phox2b-immunoreactive cells was mapped during development of the
gastrointestinal tract. At Embryonic Days 9.5-10 (E9.5-10), Phox2b-labeled cells
were present only in the stomach, and during subsequent development, labeled
cells appeared as a single rostrocaudal wave along the gastrointestinal tract; at
E14 Phox2b-labeled cells were present along the entire length of the
gastrointestinal tract. Ret and p75 have also been reported to label migratory
stage enteric neuron precursors. A unidirectional, rostral-to-caudal colonization
of the gastrointestinal tract of embryonic mice by Ret- and p75-immunoreactive
cells was also observed, and the locations of Ret- and p75-positive cells within
the gut were very similar to that of Phox2b-positive cells. To verify the
location of enteric neuron precursors within the gut, explants from
spatiotemporally defined regions of embryonic intestine, 0.3-3 mm long, were
grown in the kidney subcapsular space, or in catenary organ culture, and examined
for the presence of neurons. The location and sequence of appearance of enteric
neuron precursors deduced from the explants grown under the kidney capsule or in
organ culture was very similar to that seen with the Phox2b, Ret, and p75
antisera. Previous studies have mapped the rostrocaudal colonization of the rat
intestine by enteric neuron precursors using HNK-1 as a marker. In the current
study, all HNK-1-labeled cells in the gastrointestinal tract of rat embryos
showed immunoreactivity to Phox2b, but HNK-1 cells comprised only a small
subpopulation of the Phox2b-labeled cells. In addition, in rats, Phox2b-labeled
cells were present in advance of (more caudal to) the most caudal HNK-1-labeled
cells by 600-700 microm in the hindgut at E15. We conclude that the neural crest
cell population that arises from the vagal level of the neural axis and that
populates the stomach, midgut, and hindgut expresses Phox2b, Ret, and p75. In
contrast, the sacral-level neural crest cells that populate the hindgut either do
not express, or show a delayed expression of, all of the known markers of vagal-
and trunk-level neural crest cells.
PMID- 9758705
TI - N-cadherin/catenin-mediated morphoregulation of somite formation.
AB - Somitogenesis during early stages in the chick and mouse embryo was examined in
relation to N-cadherin-mediated adhesion. Previous studies indicated that N
cadherin localizes to the somite regions during their formation. Those
observations were extended to include a spatiotemporal immunohistochemical
analyses of beta-catenin and alpha-catenin, as well as a more detailed study of N
cadherin, during segmentation, compaction, and compartmentalization of the
somite. N-cadherin and the catenins appear early within the segmental plate and
are expressed as small patch-like foci throughout this tissue. The small foci of
immunostaining coalesce into larger clusters of N-cadherin/catenin-expressing
regions. The clusters subsequently coalesce into a region of centrally localized
cells that express N-cadherin/catenins at their apical surfaces. The multiple
clusters are spaced wide apart in the anterior segmental plates that form the
first 6 somite pairs, as contrasted to segmental plates that form somites 7 and
beyond. To examine the functional significance of N-cadherin, segmental plates
were exposed to antibodies that perturb N-cadherin-mediated adhesion in the chick
embryo. The multiple, anomalous somites that result in these experiments indicate
that each N-cadherin/catenin-expressing cluster can give rise to a somitic
structure. beta-Catenin involvement in somitogenesis suggests a role for Wnt
mediated signaling. Embryos treated with LiCl also show induction of similar
anomalous somites indicating further the possibility that Wnt-mediated signaling
may be involved in the clustering event. It is suggested that beta-catenin serves
to initiate the adhesion process which is spread then by N-cadherin. Later during
compartmentalization, N-cadherin/catenins remain expressed by the myotome
compartment. Taken together, these results suggest that the Ca2+-dependent cell
adhesion molecule N-cadherin and the intracellular catenins are important in
segmentation and formation of the somite and myotome compartment. It is proposed
that the N-cadherin-mediated adhesion process may serve as a common,
evolutionarily conserved, link in the differentiation pathways of skeletal and
cardiac muscle.
PMID- 9758706
TI - Precocious expression of the Wilms' tumor gene xWT1 inhibits embryonic kidney
development in Xenopus laevis.
AB - The tumor suppressor WT1 has been demonstrated to have a wide variety of
activities in vitro and is required for metanephric development in vivo. In the
experiments presented here, the Xenopus pronephros was used as a simple model
system to examine the activity of Xenopus WT1 (xWT1) during kidney development.
xWT1 was ectopically expressed in Xenopus embryos by mRNA injection and found to
inhibit pronephric tubule development. Confocal microscopy confirmed this
observation and revealed that the inhibition was the result of a failure to form
a pronephric anlage of appropriate size rather than a defect in
epithelialization. Examination of Xlim-1 expression, an early molecular marker of
pronephric specification, in tailbud embryos indicated that injected xWT1 mRNA
inhibited pronephric specification prior to any overt sign of morphogenesis
(Xenopus stage 21). These results suggest that xWT1 may act to repress tubule
specific gene expression in the portion of the pronephros fated to form its
vascular structure, the glomus.
PMID- 9758707
TI - Voltage-dependent activation of frog eggs by a sperm surface disintegrin peptide.
AB - Fertilin, a sperm protein of the metalloprotease/disintegrin/cysteine-rich (MDC)
family, plays a critical role in sperm-egg binding in mammals. Peptides
corresponding to the disintegrin domain of fertilin and antibodies against
fertilin have been shown to inhibit mammalian sperm-egg binding and fusion. A
protein from the same family, xMDC16, was recently cloned from frog (Xenopus
laevis) testis and was found to be involved in frog sperm-egg binding. Here we
report that xMDC16 is localized predominantly on the posterior surface of egg
jelly-activated sperm, and peptides from the disintegrin domain of this protein
activate eggs when applied near the egg surface. Egg activation was dependent on
(1) specific amino acid residues (KTX); (2) the presence of divalent cations, but
not external Ca2+ alone; and (3) voltage across the egg plasma membrane. This is
the first demonstration of egg activation in vertebrates by the surface
application of a peptide derived from a sperm surface protein, supporting a model
for egg activation that involves a signal transducing receptor for sperm in the
egg's plasma membrane.
PMID- 9758708
TI - A novel alternative spliced variant of the transcription factor AP2alpha is
expressed in the murine ocular lens.
AB - The AP2alpha gene encodes a transcription factor containing a basic, helix-span
helix DNA-binding/dimerization domain, which is developmentally regulated and
retinoic acid inducible. Recent reports about AP2alpha null mice indicate that
AP2alpha plays an important role in embryogenesis, especially in craniofacial
development and midline fusion. Ocular development is also affected in these null
mice. As AP2alpha may be involved in transcriptional regulation in the lens, it
was important to examine the expression of the AP2alpha gene in the lens. Four
AP2alpha mRNA variants have been previously isolated from whole mouse embryos.
Variants 1, 3, and 4 are transcriptional activators that are transcribed from
different promoters and variant 2 is a repressor lacking the activation domain
encoded by exon 2. Using in situ-PCR, we found that AP2alpha is expressed in the
lens epithelia but not in the lens fibers. RT-PCR analysis of lens mRNA with
amplimers specific for each variant revealed that AP2alpha variants 1, 2, and 3
are expressed in newborn mouse lenses. However, variant 4 is not expressed in the
lens. In this report we characterized a novel isoform, which we named variant 5,
expressed in the lens and kidney. Variant 5, which is generated by alternative
splicing, may function as a repressor due to the partial deletion of the proline
rich transactivation domain encoded by exon 2. This is the first molecular
characterization of AP2alpha gene expression in the lens. Our results indicate
that two activator and two repressor AP2alpha isoforms may play a role in
regulating gene expression in the lens.
PMID- 9758709
TI - Identification of gametophytic mutations affecting female gametophyte development
in Arabidopsis.
AB - The female gametophyte (embryo sac or megagametophyte) plays a critical role in
sexual reproduction of angiosperms. It is the structure that produces the egg
cell and central cell which, following fertilization, give rise to the seed's
embryo and endosperm, respectively. In addition, the female gametophyte mediates
a host of reproductive processes including pollen tube guidance, fertilization,
and the induction of seed development. Several major events occur during
megagametogenesis, including syncitial nuclear divisions, cellularization,
nuclear migration and fusion, and cell death. While these events have been
described morphologically, the molecules regulating them in the female
gametophyte are largely unknown. We discuss a genetic screen based on reduced
seed set and segregation distortion to identify mutations affecting
megagametogenesis and female gametophyte function. We report on the isolation of
four mutants (fem1, fem2, fem3, and fem4) and show that the four mutations map to
different locations within the genome. Additionally, we show that the fem1 and
fem2 mutations affect only the female gametophyte, while the fem3 and fem4
mutations affect both the female and male gametophyte. We analyzed female
gametophyte development in these four mutants as well as in the gfa2, gfa3, gfa4,
gfa5, and gfa7 mutants. We found that the fem2, fem3, gfa4, and gfa5 mutants
abort development at the one-nucleate stage, while the fem1, fem4, gfa2, gfa3,
and gfa7 mutants are affected in processes later in development such as polar
nuclei fusion and cellularization. The establishment of a genetic screen to
identify mutants and the development of a rapid procedure for analyzing mutant
phenotypes represent a first step in the isolation of molecules that regulate
female gametophyte development and function.
PMID- 9758710
TI - Volume 92, number 2 (1997), in article no. DB978773, "Localized maternal proteins
in xenopus revealed by subtractive Immunization," by james M. Denegre, erich R.
Ludwig, and kimberly L. Mowry, pages 446-454
PMID- 9758711
TI - Regulation and function of pulmonary surfactant protein B.
AB - Pulmonary surfactant, a complex mixture of phospholipids and specific associated
proteins, reduces the surface tension at the air-liquid interface of the distal
conducting airways and gas exchanging alveoli of the lung. Lipids, primarily
neutral and phospholipids, compose approximately 90% of the surfactant complex.
The remaining 10% of surfactant is composed of at least three surfactant-specific
proteins, designated surfactant protein A (SP-A), SP-B, and SP-C. These proteins
contribute to the formation, stabilization, and function of organized surfactant
structures. This article briefly reviews the normal composition and function of
pulmonary surfactant and specifically reviews the structure, function, and
regulation of surfactant protein B (SP-B). The recent identification of neonates
with refractory respiratory failure due to a genetic absence of SP-B and the
study of transgenic mice in which SP-B gene expression has been ablated highlight
the importance of the protein to surfactant function, synthesis, and metabolism
and to the maintenance of lung function. Gene reconstitution experiments in vitro
and in SP-B-deficient transgenic mice suggest specific functions for the amino
and carboxyl terminal domains of the protein. SP-B deficiency is a potential
target for gene therapy in human patients.
PMID- 9758712
TI - Identification of four novel mutations in patients with carnitine
palmitoyltransferase II (CPT II) deficiency.
AB - Carnitine palmitoyltransferase II (CPT II) deficiency, an autosomal recessive
disorder of fatty-acid oxidation, presents as three distinct phenotypes
(neonatal, infantile, and adult onset). In order to investigate the molecular
basis of these three phenotypes, six patients with CPT II deficiency have been
studied. All six unrelated patients in this study experienced the clinical
symptoms of CPT II deficiency. Three patients had the neonatal form, one had the
milder infantile form, and the remaining two had the adult-onset form with
"muscular" symptoms only. Their diagnoses were based upon in vitro analysis of
the mitochondrial beta-oxidation pathway in fibroblasts and standard enzyme
assays. We devised a method to screen the entire coding sequence and flanking
splice junction of the CPT II gene. A total of six different mutations have been
identified, including four novel mutations. Among them, the previously reported
common mutation, S113L, was only found in 3 of 12 variant alleles. Three of the
six mutations have been identified in a few unrelated patients, while the
remaining three have been found in single families. This study, as well as those
by others, indicates genetic heterogeneity in this disease. In addition to
tabulating the mutations, the correlation of mutant genotype to clinical
phenotype is briefly discussed.
PMID- 9758713
TI - A randomized clinical trial of topical cysteamine disulfide (cystamine) versus
free thiol (cysteamine) in the treatment of corneal cystine crystals in
cystinosis.
AB - In nephropathic cystinosis, corneal cystine crystals cause severe photophobia and
corneal erosions. Topical cysteamine dissolves these crystals, but cannot be
marketed because it rapidly oxidizes to the disulfide form, cystamine, at room
temperature. Since cystamine itself could be used commercially, we compared the
efficacy of cystamine and cysteamine with respect to cystine crystal dissolution
in a randomized, double-masked clinical trial. One eye each of 14 patients with
cystinosis was randomized to either cystamine or cysteamine, 0.5%, with 0.01%
benzalkonium chloride; the companion eye was treated with the alternate
preparation. Corneal crystals were photographed and a density score was assigned
to each slide based on 13 standard slides. After 8-20 months, 6 patients showed
significant reduction of the corneal crystal score in only one eye. In each case,
the improved eye was the cysteamine-treated eye. Theoretically, cysteamine should
dissolve both intracellular and extracellular crystals, whereas cystamine should
dissolve only intracellular crystals because it must first be reduced to the free
thiol by the cytoplasmic-reducing environment. Hence, the lack of efficacy of the
disulfide cystamine suggests that some corneal cystine crystals in cystinosis
patients are extracellular, and that another form of stable, topical cysteamine
must be developed for cystinosis patients.
PMID- 9758715
TI - Deficiency of biotinyl-AMP synthetase activity in fibroblasts of patients with
holocarboxylase synthetase deficiency.
AB - A simple, rapid assay was developed to diagnose holocarboxylase synthetase
deficiency. Holocarboxylase synthetase first catalyzes the formation of biotinyl
AMP from biotin and ATP, an activity designated as biotinyl-AMP synthetase. In
the second step of the reaction, biotin is transferred from biotinyl-AMP to the
enzymatically inactive apocarboxylase to form an active holocarboxylase. The
assay for holocarboxylase synthetase activity therefore requires a protein
apocarboxylase substrate which is not readily available. In the assay for
biotinyl-AMP synthetase, hydroxylamine reacts nonenzymatically with the product
of the enzymatic reaction, biotinyl-AMP, to form biotinylhydroxamate. At the end
of the reaction, unreacted radioactive biotin substrate, which is negatively
charged at neutral pH, is bound to an anion-exchange resin and a neutral
radioactive biotinylhydroxamate product in the supernatant is counted. In
fibroblasts from 11 patients with proven holocarboxylase synthetase deficiency,
the mean biotinyl-AMP synthetase activity at 25 nM biotin was 4% of the control
mean with a range of 0.2 to 8%. This is an improved assay because it does not
require preparation of an apocarboxylase substrate and is suitable for the
diagnosis of patients with holocarboxylase synthetase deficiency.
PMID- 9758714
TI - Molecular basis of hyperargininemia: structure-function consequences of mutations
in human liver arginase.
AB - Hyperargininemia is a rare autosomal recessive disorder that results from a
deficiency of hepatic type I arginase. At the genetic level, this deficiency in
arginase activity is a consequence of random point mutations throughout the gene
that lead to premature termination of the protein or to substitution mutations.
Given the high degree of sequence homology between human liver and rat liver
enzymes, we have mapped both patient and nonpatient mutations of the human enzyme
onto the structure of the rat liver enzyme to rationalize the molecular basis for
the low activities of these mutant arginases. Mutations identified in
hyperargininemia patients affect the structure and function of the enzyme by
compromising active-site residues, packing interactions in the protein
scaffolding, and/or quaternary structure by destabilizing the assembly of the
arginase trimer.
PMID- 9758716
TI - Genetic heterogeneity of adrenocorticotropin (ACTH) resistance syndromes:
identification of a novel mutation of the ACTH receptor gene in hereditary
glucocorticoid deficiency.
AB - Hereditary primary adrenal insufficiency syndromes due to ACTH resistance include
hereditary glucocorticoid deficiency (HGD) and Allgrove's syndrome (AS). Patients
with both conditions present in childhood with failure to thrive, weakness, and
fatigue or adrenal crisis; patients with AS in addition have alacrima and
achalasia (triple A syndrome). We studied four kindreds with HGD and four
kindreds with AS for abnormalities of the ACTH receptor (ACTHR) gene. The ACTHR
coding sequence in all AS kindreds and two HGD kindreds was normal. Analysis of
the ACTHR gene of the proband in one of the HGD kindreds showed him to be
homozygous for the previously described G221T transition causing a Ser74Ile
substitution of the protein, which has been shown to inactivate the ACTHR in
signal transduction. The proband in another HGD kindred was found to be a
compound heterozygote with the G221T transition in one allele and a novel C818A
transition in the other allele of ACTHR. The C818A transition caused the
substitution of the highly conserved Pro273 by His in the receptor protein. In
vitro expression of the mutated ACTHR in mouse melanoma M3 cells showed that at a
medium ACTH concentration of 3 nM, cells transfected with the wild-type ACTHR
produced twofold and threefold, respectively, of the amount of intracellular cAMP
when compared to cells transfected with the ACTHR carrying the Pro273His and the
Ser74Ile mutation, respectively, confirming that HGD in this kindred is caused by
loss-of-function mutations of the ACTHR. These results showed that the genetic
cause of the ACTH-resistant syndromes is heterogeneous.
PMID- 9758717
TI - PCR-based methods for identifying genetic variations in human alpha1B- and beta2
adrenergic receptors.
AB - alpha- and beta-adrenergic receptors belong to the superfamily of G-protein
coupled, seven transmembrane domain receptors and regulate a variety of cellular
processes. Previous studies have demonstrated that changes in the amino acid
sequence can result in substantial changes in the function of the receptors and
it has been suggested that there may be an association between different disease
states and the altered structure of alpha- and beta-adrenergic receptors.
Accordingly, we have developed a simple PCR method for the identification of
polymorphisms in the coding sequences of the human beta2-adrenergic receptor and
the alpha1B-adrenergic receptor. This method may be useful for screening
individual patients or at-risk populations for endocrine-metabolic disorders, as
well as for asthma, cardiovascular disorders, and neuropsychiatric diseases.
PMID- 9758718
TI - Differential gene expression in apoptosis: identification of ribosomal protein
23K, a cell proliferation inhibitor.
AB - Gene expression during the camptothecin-induced apoptotic death of human leukemic
U937 cells and mouse T-cell hybridoma QW4.1 cells was studied by the mRNA
differential display technique. Ten clones were confirmed to be differentially
expressed, nine of which encoded novel sequences. One clone, U3.2, was induced
approximately 10-fold in camptothecin-treated cells and was found to be identical
to a highly basic 23-kDa human protein which contains basic leucine zipper-like
motifs and has recently been identified as the human homologue of the rat
ribosomal protein L13a. Northern blot analysis revealed a major mRNA of
approximately 0.9 kb and a minor mRNA of approximately 1.3 kb. Overexpression of
a full-length 23K cDNA, tagged with a FLAG sequence, in COS-7 cells revealed a
predominantly nucleolar localization and the absence of any 23K protein from the
cytoplasm. Subsequent transfection studies, using antisense phosphorothioate
modified oligonucleotides, revealed that inhibition of 23K expression results in
an increased cell proliferation and greater sensitivity of U937 cells to the
effects of camptothecin-induced cell death. Upregulation of 23K expression using
a cDNA construct resulted in a decrease in cell proliferation and growth arrest,
suggesting a role for 23K protein as a proliferation checkpoint following a
cellular insult.
PMID- 9758719
TI - Structural specificity of serotonin effect on human erythrocyte fragility.
AB - Serotonin, a neurotransmitter and vasoconstrictor, affects various cell
properties. We have analyzed the importance of its structural components for its
extensive effect on human erythrocyte fragility, using its O- and N-linked
derivatives and related compounds. The results presented in this communication
indicate that the amino group, free of adjacent negative charges, and the
hydroxyl group are indispensable for the serotonin-induced increase in red blood
cell fragility.
PMID- 9758721
TI - Alteration of the intestinal intraepithelial lymphocytes during total parenteral
nutrition.
AB - Total parenteral nutrition (TPN) may cause increased rates of bacterial
translocation (BT), possibly due to a loss of epithelial integrity. Cultured
epithelial cells have been shown to lose tight junction integrity with interferon
gamma (INF-gamma) an action which may be blocked by transforming growth factor
beta (TGF-beta). Because intraepithelial lymphocytes (IEL) are a rich source of
these cytokines in the epithelium, we hypothesized that changes in the IEL, while
mice were receiving TPN, may be responsible for the mediation of such cytokine
responses. C57BL/6 mice were randomized to a Control group which received
intravenous saline and mouse chow, or a TPN group which received intravenous TPN
with no oral feeding. At 7 days mice were assessed for BT. Isolated IEL were
stained for CD4, CD8, and CD44 (as a marker for memory T-cells) and flow
cytometry was performed. mRNA was extracted from remaining IEL for cytokine
expression. Reverse transcriptase polymerase chain reaction was performed to
detect TGF-beta1 and INF-gamma mRNA expression. Densities were standardized to
beta-actin expression. The incidence of BT to mesenteric lymph nodes was 40 and
12.5%, for the TPN and Control groups, respectively. TPN led to statistically
significant decreases in the CD4+, CD8-; CD4+, CD8+; and the CD8+, CD44+ IEL
subpopulations (P < 0.05). mRNA expression for INF-gamma was increased by 53% (P
< 0.05), and TGF-beta1 mRNA expression was decreased by 75% (P = 0.1) in the IEL
of TPN mice when compared with Controls. TPN led to significant changes in the
IEL. Such alterations of the IEL phenotype and function may be a critical
mechanism by which epithelial integrity is lost.
PMID- 9758720
TI - Carrier frequency of the Bloom syndrome blmAsh mutation in the Ashkenazi Jewish
population.
AB - Bloom syndrome is more common in individuals of Ashkenazi Jewish descent than in
any other population, and one particular mutation in the Bloom syndrome gene,
blmAsh, is homozygous in nearly all Ashkenazi Jewish persons with Bloom syndrome.
We have determined the frequency of blmAsh in 1491 Ashkenazi Jewish persons with
no known history of Bloom syndrome and found that 1 in 107 persons was
heterozygous. Although not common, genetic screening for Bloom syndrome is
feasible in this population.
PMID- 9758722
TI - The basis for progesterone impairment of gallbladder contractility in male guinea
pigs in vitro.
AB - Progesterone suppresses gallbladder smooth muscle function but its exact
mechanism is unknown. We sought to determine the cellular site where progesterone
impairs gallbladder smooth muscle. Sixty-four adult male guinea pigs were
injected with either progesterone (2 mg/kg/day sc) or normal saline (controls)
for 7 days. Dose-response curves of gallbladder strips to cholecystokinin (CCK),
bethanechol, and potassium (K+) were constructed in vitro. To better define the
basis for the progesterone effect, gallbladder contractile response was
determined to specific agonists: aluminum fluoride and mastoparan (direct G
protein activators), cyclopiazonic acid (CPA), and a calcium ionophore (A-23187).
Gallbladder from animals on progesterone exhibited a marked decrease in
contractile response to CCK and bethanechol compared with controls (P < 0.05).
Further, gallbladder contraction remained depressed (P < 0.05) in progesterone
treated animals, when the G protein was directly activated with aluminum fluoride
and mastoparan. In contrast, the responses to K+ (acting independent of receptor
G-protein) and to A-23187 and CPA (agonists that bypassed the membrane) were
comparable in both groups (NS). It is concluded that progesterone directly
inhibits gallbladder smooth muscle contractility in vitro to a standard hormone,
CCK, and a cholinergic agent. Such depressed contraction is not due to an altered
contractile machinery, since it is normal with agonists that act independently of
G-protein activation. Progesterone thus interferes with signaling through the G
protein, either by directly becoming closely associated with the cell membrane or
by indirectly perturbing its receptor products.
PMID- 9758723
TI - Early gene expression associated with regeneration is intact after massive
hepatectomy in rats.
AB - BACKGROUND: Liver regeneration occurs promptly after partial hepatectomy,
although the factors regulating this response have not been fully clarified.
Molecular events in the regenerative response have been widely characterized
after 70% hepatectomy which represents a model of "normal" liver regeneration in
rats. More extensive resection results in hepatic failure which has been
attributed to a critical loss of hepatic mass. It is not known whether the
pattern of genes expressed early in regeneration remains intact after lethal
hepatectomy. We hypothesize that the increased expression of selected early
response genes remains intact after massive hepatectomy. The aim of this study
was to compare the expression of selected genes after 70 and 85% hepatectomy.
MATERIALS AND METHODS: One hundred ten Wistar rats were divided into three
groups: control group (sham laparotomy) (n = 30), 70% hepatectomy group (n = 40),
and 85% hepatectomy group (n = 40). Animals were sacrificed at intervals. Livers
were excised and divided into four equal specimens, snap frozen, and stored at
70 degrees C. RNA was extracted by standard methods and preparations were probed
for protooncogenes, c-myc, c-fos, and for hepatocyte growth factor, and its
receptor, c-met. After overnight exposure of autoradiographs, quantification was
accomplished by densitometry of RNA slot blots. RESULTS: After 70% hepatectomy,
peaks of maximal expression for both c-myc and c-met were observed after 1 and 12
h. For c-fos, peak of maximal expression was observed at 6 h. For HGF, peak was
observed between 12 h and Day 2. After 85% hepatectomy, rats demonstrated similar
patterns including peak expression of c-myc at 1 h, but altered peak at 12 h. For
c-met, the same pattern was observed between 1 and 12 h. For HGF, two peaks were
noted: a first peak at 1 h, and a peak similar to the peak observed after 70%
hepatectomy at 12 h. CONCLUSIONS: These results suggest that early molecular
events which are part of the regenerative response are largely intact after 85%
lethal hepatectomy. We propose that liver dysfunction and the failure of
regeneration observed after 85% hepatectomy is not due to alteration of early
signaling. Further study will be required to define failure of the regeneration
program in this model.
PMID- 9758724
TI - Vasopressin antagonist improves renal function in a rat model of
pneumoperitoneum.
AB - Pneumoperitoneum (PP) is associated with oliguria and increased plasma arginine
vasopressin (AVP) levels. This study investigated the role of AVP in the
pathogenesis of oliguria due to PP. Anesthetized and ventilated rats (n = 12)
were subjected for 1 h to carbon dioxide PP with an intra-abdominal pressure of 8
mmHg or, as control, at 0 mmHg, before the determination of plasma AVP level.
Another group of rats (n = 48) subjected to PP or control conditions was
pretreated with the AVP V2 receptor antagonist, OPC-31260 (5 mg/kg), or vehicle,
and their renal parameters were measured. Glomerular filtration rate (GFR) was
determined by inulin clearance in an additional group of rats (n = 12) subjected
to PP with or without pretreatment with OPC-31260. Rats subjected to PP had
higher plasma AVP levels than did controls (17.3 +/- 8.1 pg/ml vs 1.5 +/- 0. 6
pg/ml, P < 0.05). In rats pretreated with vehicle, PP decreased urine output,
excretion of water, and urea nitrogen, leading to reduced serum osmolality and
serum sodium levels as well as elevated blood urea nitrogen levels. OPC-31260
pretreatment improved urine output, excretion of water, and urea nitrogen,
thereby preventing changes in serum osmolality, serum sodium levels, and blood
urea nitrogen levels. OPC-31260 pretreatment did not affect GFR. Results suggest
that plasma AVP contributes to the oliguria due to PP. OPC-31260 may be useful in
treating the water retention associated with PP.
PMID- 9758725
TI - Lymphokine-activated killer (LAK) cell anti-HIV-1 ADCC reactivity: a potential
strategy for reduction of virus-infected cellular reservoirs.
AB - Lymphocytes from HIV-1-seropositive and -seronegative individuals were examined
to determine whether HIV-1 infection interfered with the ability to generate a
lymphokine-activated killer (LAK) cell response. Following a 3-day ex vivo
incubation in the presence of 1000 U/ml of recombinant interleukin-2, lymphocytes
from seropositive individuals exhibited a LAK cell response which was equivalent
to or greater than that of seronegative controls as measured against Daudi cell
targets. LAK cells from seropositive and seronegative donors showed no specific
cytolytic activity against gp120-coated or HIV-1-infected targets. However, in
the presence of patient sera, significant levels of virus-specific LAK cell
mediated antibody-dependent cellular cytotoxicity (ADCC) were observed. The level
of this specific LAK cell-mediated ADCC was greater than that mediated under
similar conditions by freshly isolated peripheral blood mononuclear cells. The
greatest improvement in ADCC over baseline activity was seen with lymphocytes
from AIDS patients after the 3-day ex vivo activation, suggesting that this
patient population might benefit the most from adaptive LAK cell therapy.
PMID- 9758726
TI - Nitric oxide causes apoptosis in pulmonary vascular smooth muscle cells.
AB - Nitric oxide (NO), a product of certain cytokine-activated cells, affects rates
of apoptosis, a mechanism of programmed cell death. We asked whether NO affected
rates of apoptosis in pulmonary vascular cells. Using rat pulmonary artery smooth
muscle cells, we studied direct effects of the NO donor SG-nitroso-acetyl-D,L
penicillamine (SNAP) and the effects of NO endogenously synthesized in response
to bacterial lipopolysaccharide (LPS) and inflammatory cytokines interleukin
1beta, interferon-gamma, and tumor necrosis factor-alpha (a combination called
cytomix for convenience). We determined apoptosis on the basis of light
microscopy and the bromodeoxyuridine terminal deoxynucleotidyl transferase
reaction (BrdUTdT). Both SNAP- and cytomix-induced synthesis of NO resulted in
histologic evidence of apoptosis based upon fluorescence microscopy using
propidium iodide. SNAP (10(-5) M) increased BrdUTdT-positive cells from 17.5 to
78.4% compared with basal medium alone, with the maximal response occurring at 15
h or exposure. Exposing cells to LPS and cytokines induced NO production (from
0.1 +/- 0.1 to 24.6 +/- 0.5 microM, P < 0.05) caused cytological changes
consistent with apoptosis and led to an increase of increased BrdUTdT-positive
cells from 11 to 41% at 12 h compared with basal medium alone. The competitive NO
synthase inhibitor NG-monomethyl-L-arginine inhibited both NO synthesis and NO
apoptosis, returning the proportion of BrdUTdT-positive cells (6%) to levels
below control. L-Arginine (0.5 mM) restored percentages to those increase in
response to endogenously synthesized NO, and NO is a potential mechanism of acute
lung injury in response to inflammatory cytokines.
PMID- 9758727
TI - IL-10 and GM-CSF expression and the presence of antigen-presenting cells in
chronic venous ulcers.
AB - BACKGROUND: White cell trapping and activation occurs in the legs of patients
having chronic venous insufficiency (CVI), and it is thought that this process
may be important in the development of CVI ulcers. This study has compared the
tissue distribution of proinflammatory (GM-CSF) and anti-inflammatory cytokines
(IL-10) and inflammatory cell markers (CD68, HLA-DR) between CVI ulcers, other
chronic and acute wounds, and autologous nonwounded skin to determine whether
cell-mediated immunity (CMI) is impaired in CVI ulcers. METHODS: Wound and donor
site tissue was obtained from 10 patients with CVI ulcers and 10 patients with
other chronic and acute wounds. Serial Formalin-fixed sections were processed by
standard hematoxylin and eosin staining or by indirect immunoperoxidase
histochemical staining. RESULTS: HLA-DR-positive antigen-presenting cells (APC),
including CD68-positive macrophages and dermal dendritic cells, were found with
greater frequency in CVI ulcers than in other chronic or acute wounds (P =
0.0015) or in the autologous CVI donor site tissue (P = 0.006). CVI ulcers also
demonstrated increased IL-10 staining of the entire epidermis compared to non-CVI
wounds (P = 0.0019) or autologous donor site tissue (P = 0.004), whereas there
was no significant change in the presence of the counteracting cytokine, GM-CSF.
CONCLUSIONS: These findings suggest that although the cellular components of CMI
are present in CVI ulcers, their function may be impaired by the increased level
of IL-10. Future studies will examine whether IL-10-mediated suppression of CMI
and/or inhibition of GM-CSF-stimulated keratinocyte proliferation may contribute
to the chronic nature of CVI ulcers.
PMID- 9758728
TI - The Kidney's role in glucose balance following partial hepatectomy.
AB - It has long been believed that the liver is the major contributor to glucose
balance during fasting and stressful situations. Recently, investigators have
implicated the kidney as having a significant contribution to systemic glucose
appearance. We studied the relative contributions of the kidney and liver to
glucose homeostasis in fasted nonoperated, sham-operated, and 70% hepatectomized
rats. Systemic glucose appearance, renal glucose release and uptake, and hepatic
glucose release were determined by glucose balance and isotopic dilution
techniques. Systemic glucose appearance remained unchanged following hepatectomy.
There was a significant output of glucose by the kidney in all groups, accounting
for >50% of total glucose appearance. Despite the kidney's appreciable
contribution to circulating glucose in the postabsorptive state, renal glucose
release was not increased in the hepatectomized rats compared to controls. Total
glucose appearance was maintained following hepatectomy by an increase in hepatic
glucogenesis. There was a significant increase in the rate of hepatic glucose
release from resected rats when normalized to gram of remaining liver (P <
0.001). Despite the substantial amount of renal glucose output in the
postabsorptive state, preservation of glucose balance following 70% hepatectomy
is accomplished by adaptation in hepatic glucose output.
PMID- 9758729
TI - Acute administration of liposomal coenzyme Q10 increases myocardial tissue levels
and improves tolerance to ischemia reperfusion injury.
AB - The antioxidant and bioenergetic effects of CoQ10 (CoQ) suggest it might be ideal
therapy for acute myocardial ischemia. Its utility is limited by the requirement
for enteral administration. This study related the administration of a new
liposomal suspension of CoQ given intravenously to (1) serum and myocardial [CoQ]
and (2) recovery of function, myocardial efficiency, and oxidant injury after
cardiac ischemia and reperfusion (I/R). Rats (n = 8/group) were given liposomal
CoQ 10 mg/kg iv or placebo (Control), 15 min (C-15), 30 min (C-30), and 60 min (C
60) before (1) measurement of serum and myocardial CoQ or (2) Langendorff
perfusion of hearts subjected to 15 min equilibration, 25 min ischemia (37
degrees C), and 40 min reperfusion (RP). Developed pressure (DP) was measured via
an intraventricular balloon and coronary flow was measured by a digital flow
meter. Myocardial efficiency was defined as DP/MVO2 where MVO2 = microl O2
consumed/min/gram LV. At end RP hearts were assayed for CK, an oxidant sensitive
enzyme. Maximum preischemic CoQ levels in serum and myocardium occurred 15 and 30
min after administration, respectively. At end reperfusion, C-30 hearts improved
the most, recovering 75 +/- 4% of their preischemic DP while Control recovered
only 52 +/- 6% (P < 0.03) as well as maintaining better myocardial efficiency
(0.69 +/- 0.02 vs Control, 0.43 +/- 0.05) (P < 0.001). C-15, C-30, and C-60
groups all lost less CK activity after RP vs Control (P < 0.04). CONCLUSION: (1)
Serum and myocardial levels of CoQ can be raised acutely by iv liposomal CoQ. (2)
Myocardial CoQ levels correlate best with I/R protection. (3) Acute iv CoQ
improves function and efficiency and decreases oxidant injury after I/R.
Intravenous CoQ may be effective clinically for acute cardiac ischemic syndromes.
PMID- 9758730
TI - Application of a rat osteomyelitis model to compare in vivo and in vitro the
antibiotic efficacy against bacteria with high capacity to form biofilms.
AB - A rat experimental osteomyelitis model was used to study the efficiency of
antibiotics on biofilm bacteria adhered to implants in relation to the efficiency
obtained in vitro. In the osteomyelitis model, 10(4) bacteria of the strain
variant used for the in vitro studies (a slime-producing variant of
Staphylococcus aureus) were inoculated into the rat tibia at surgery, after
implanting a stainless steel canula precolonized for 12 h with this strain. After
5 weeks, a 21-day antibiotic treatment was applied (using cefuroxime, vancomycin,
or tobramycin). Subsequently, implant and tibia were studied for presence of
bacteria. In this osteomyelitis model, cefuroxime inhibited bone colonization and
reduced the number of bacteria in metal and bone at a higher degree (P < 0.05)
than vancomycin and trobramycin (the latter antibiotic did not have this
reduction effect). The in vitro assay was applied using three concentrations of
each antibiotic (8, 100, and 500 microg/ml) and 6-, 24-, and 48-h biofilms.
Bacterial viability was evaluated by ATP-bioluminescence after 24 h of antibiotic
treatment. In this in vitro assay, cefuroxime significantly (P < 0.05) reduced in
all cases the number of viable bacteria in biofilms, tobramycin did not affect
viability, and vancomycin affected viability except at the lowest concentration
used (8 microg/ml, i.e., 8x the minimal bactericidal concentration of this
antibiotic) when facing the oldest (48 h) biofilm. These results demonstrate the
usefulness of the osteomyelitis model applied in providing evidence for a close
correlation between the in vitro and in vivo findings on the effect of three
antibiotics under study.
PMID- 9758731
TI - Oral dehydroepiandrosterone inhibits the growth of human pancreatic cancer in
nude mice.
AB - BACKGROUND: Dehydroepiandrosterone (DHEA), an androgen precursor, inhibits the
induction of pancreatic cancer in some animal models. Our laboratory has
previously demonstrated that the sulfated form of DHEA (DHAS), when administered
by intraperitoneal injection, inhibits the growth of pancreatic cancer xenografts
in nude mice. In the present study, we hypothesize that DHEA-mediated pancreatic
cancer growth inhibition is associated with alterations in plasma sex hormone
concentrations. MATERIALS AND METHODS: Forty male, nude, athymic mice were fed
either Teklad 22/5 rodent diet or diet supplemented with 0.6% DHEA ad libitum.
Four weeks following the institution of the experimental diets, 1 x 10(6) MiaPaCa
2 cells were injected into the right flank of each animal. Tumor area was
recorded weekly and tumor weights were measured after 5 weeks. Plasma DHAS,
testosterone, and progesterone concentrations were determined by
radioimmunoassay. RESULTS: Plasma DHAS, testosterone, and progesterone
concentrations were all significantly elevated in the DHEA-treated group. DHEA
treated mouse plasma DHAS concentrations were approximately 50-fold higher than
controls. Mean tumor weight was significantly reduced in the DHEA group (68.9 +/-
39.1 vs 121.0 +/- 64.3). DHEA treatment did not result in significant animal
weight reductions and toxic side effects were not observed. CONCLUSIONS: Dietary
supplementation with 0.6% DHEA causes significant elevations in plasma DHAS
concentration. DHEA administration significantly inhibits pancreatic cancer cell
growth at plasma concentrations 1 x 10(5)-fold lower than previously reported.
The mechanism of action may involve elevated concentrations of sex hormones.
PMID- 9758732
TI - Glucocorticoid attenuates a decrease of antithrombin III following major surgery.
AB - BACKGROUND: Major surgery, such as esophagectomy, activates inflammatory
responses and the coagulation system, and this activation is characterized by
release of inflammatory cytokines and a decrease in antithrombin-III (AT-III),
respectively. Preoperative glucocorticoid administration has been reported to
suppress circulatory cytokine levels after major surgery. PATIENTS AND METHODS: A
total of 28 patients underwent esophagectomy for esophageal carcinoma; 14 of them
were given 10 mg/kg of methylprednisolone intravenously upon induction of
anesthesia and 14 served as controls. Circulating levels of tumor necrosis factor
alpha (TNF-alpha), interleukin 6 (IL-6), polymorphonuclear (PMN) elastase,
thrombin-antithrombin III complex (TAT), AT-III, and albumin were measured before
and immediately after the operation and on postoperative days (PODs) 1, 3, 5, and
7. RESULTS: TNF-alpha, IL-6, and TAT levels significantly increased after
esophagectomy in both groups. AT-III and albumin decreased to their minimum
levels on POD 1 and POD 3, respectively. Methylprednisolone treatment effectively
inhibited the increases in TNF-alpha and IL-6 and the decreases in AT-III and
albumin, but did not inhibit the increases in PMN-elastase and TAT levels. There
were significant correlations between AT-III, IL-6, and albumin levels.
CONCLUSIONS: These results suggest that methylprednisolone pretreatment
attenuates the decrease in AT-III by reducing IL-6 production postoperatively.
PMID- 9758733
TI - Pyruvate augments mechanical function via activation of the pyruvate
dehydrogenase complex in reperfused ischemic immature rabbit hearts.
AB - BACKGROUND: Reperfusion of ischemic adult hearts is associated with increased
fatty acid oxidation, reduced pyruvate oxidation, and reduced pyruvate
dehydrogenase (PDH) activity, leading to a decrease in cardiac efficiency. These
effects may be amplified in newborn hearts because of the immaturity of their PDH
pathway. We hypothesize that pyruvate can augment mechanical function in the
immature heart by activating the PDH complex (PDC) during reperfusion in severely
ischemic hearts. MATERIALS AND METHODS: Seven-day old isolated working rabbit
hearts (n = 12) were perfused with modified Krebs solution containing 0.4 mM
palmitate. Pyruvate (5 mM) was added for a 10-min period either before or after a
30-min period of normothermic global ischemia. Cardiac functional indices before
global ischemia and during reperfusion were correlated with active and total PDC
activity measured in 28 additional hearts frozen at the various time points
throughout the perfusion protocol. RESULTS: Addition of pyruvate before ischemia
increased the proportion of active PDC but did not affect any measured functional
indices. During early reperfusion, aortic flow, cardiac output, and cardiac work
were all significantly depressed compared to preischemic values. Addition of
pyruvate significantly increased the proportion of active PDC and was also
associated with a significant increase in aortic flow, cardiac work, and
developed pressure. Removal of pyruvate from the perfusate resulted in a
subsequent significant decrease in PDC activity and these functional parameters.
CONCLUSION: During reperfusion of neonatal rabbit hearts, addition of pyruvate
improves cardiac performance in association with activation of PDC.
PMID- 9758734
TI - In vitro effects of Clostridium difficile toxins on hepatocytes.
AB - BACKGROUND: Clostridium difficile infections are associated with development of
the systemic inflammatory response, including the production of hepatic acute
phase proteins. Lipopolysaccharide (LPS) directly stimulates the production of at
least one of these proteins, a 23-kDa acute phase protein (the LPS-induced
protein, or LIP) by murine hepatocytes in vitro. The aim of the present study was
to determine if C. difficile toxins also stimulated the synthesis of this protein
in vitro. METHODS: Cultured murine hepatocytes were treated for 24 h with various
concentrations of C. difficile culture extract or purified toxins A and B in the
presence or absence of dexamethasone or interleukin-1 (IL-1) receptor antagonist
(IL-1 RA). The cells were then metabolically radiolabeled with [35S]methionine.
Secretory proteins were identified using electrophoresis and autoradiography, and
their synthesis was quantitated by image analysis of the autoradiograms. RESULTS:
The C. difficile culture extract, at dilutions as low as 1:200,000, significantly
stimulated LIP synthesis in vitro. Toxins A and B, at concentrations as low as
1.6 and 0.02 pg/ml, respectively, also induced production of this protein.
Dexamethasone further augmented C. difficile toxin-stimulated synthesis of LIP,
but IL-1 RA inhibited the effects of these toxins on the synthesis of this
protein. Only minimal quantities of IL-1 were found in culture supernatants
following treatment with the toxins. CONCLUSIONS: C. difficile toxins A and B, at
very low concentrations, stimulate hepatocyte acute phase protein synthesis. Even
though IL-1 RA inhibits this process, it does not appear that local production of
IL-1 mediates the action of these toxins.
PMID- 9758736
TI - Association for academic surgery, 32nd annual meeting
PMID- 9758735
TI - Interleukin 10 inhibits alveolar macrophage production of inflammatory mediators
involved in adult respiratory distress syndrome.
AB - BACKGROUND: Adult respiratory distress syndrome (ARDS) causes severe morbidity
and mortality in trauma patients. One potential method to attenuate the lung
injury is to inhibit alveolar macrophage production of proinflammatory mediators.
The purpose of this study was to investigate the cellular mechanism of
interleukin 10 (IL-10) inhibition on LPS-stimulated macrophage (Mphi). We
hypothesized that IL-10 inhibited phospholipase C signal pathways in Mphi. IL-10
inhibition would be restored by calcium ionophores and protein kinase C (PKC)
activation. METHODS: Rabbit alveolar Mphi were obtained by bronchoalveolar
lavage. Mphi were treated with Escherichia coli LPS (10 ng/ml) in the presence of
various concentrations of human IL-10. Cell lysates and supernatant were analyzed
for proagulants (PCA) and tumor necrosis factor (TNF), respectively. TNF mRNA
expression of alveolar Mphi was also measured by Northern Blot assay. Macrophage
PGE2 production was measured by ELISA. RESULTS: IL-10 inhibited the production of
both TNF and PCA by LPS-stimulated Mphi. In addition, IL-10 also reduced TNF mRNA
expression. Similarly, PGE2 production by LPS-stimulated Mphi was also attenuated
by IL-10. An increase in the intracellular [Ca2+] induced by A23187 failed to
reverse this IL-10-mediated inhibition. In comparison, phorbol myristate acetate,
a protein kinase C (PKC) activator, restored TNF and PCA production despite the
presence of IL-10. CONCLUSIONS: IL-10 inhibits Mphi production of inflammatory
mediators. This inhibition is, at least in part, mediated by modulating the PKC
activity.
PMID- 9758737
TI - Identification of EEG events in the MR scanner: the problem of pulse artifact and
a method for its subtraction.
AB - Triggering functional MRI (fMRI) image acquisition immediately after an EEG event
can provide information on the location of the event generator. However, EEG
artifact associated with pulsatile blood flow in a subject inside the scanner may
obscure EEG events. This pulse artifact (PA) has been widely recognized as a
significant problem, although its characteristics are unpredictable. We have
investigated the amplitude, distribution on the scalp, and frequency of
occurrence of this artifact. This showed large interindividual variations in
amplitude, although PA is normally largest in the frontal region. In five of six
subjects, PA was greater than 50 microV in at least one of the temporal,
parasagittal, and central channels analyzed. Therefore, we developed and
validated a method for removing PA. This subtracts an averaged PA waveform
calculated for each electrode during the previous 10 s. Particular attention has
been given to reliable ECG peak detection and ensuring that the average PA
waveform is free of other EEG artifacts. Comparison of frequency spectra for EEG
recorded outside and inside the scanner, with and without PA subtraction, showed
a clear reduction in artifact after PA subtraction for all four frequency ranges
analyzed. As further validation, lateralized epileptiform spikes were added to
recordings from inside and outside the scanner: PA subtraction significantly
increased the proportion of these spikes that were correctly identified and
decreased the number of false spike detections. We conclude that in some
subjects, EEG/fMRI studies will be feasible only using PA subtraction.
PMID- 9758738
TI - Phase navigator correction in 3D fMRI improves detection of brain activation:
quantitative assessment with a graded motor activation procedure.
AB - Motion poses severe problems for BOLD fMRI, particularly in clinical studies, as
patients exhibit more involuntary movements than controls. This study focuses on
the merits of a motion correction technique incorporated in multishot fMRI scans,
so-called phase navigator correction. The technique entails real-time assessment
and off-line elimination of signal fluctuations caused by subject motion. The
purpose of this study was to quantify and characterize the effect of this type of
improvement on 3D fMRI brain activity maps. For imaging, the 3D PRESTO method was
used, with a relatively simple finger opposition task. The followed strategy was
guided by the notion that application of any fMRI imaging tool in clinical
studies requires several qualities, such as high and spatially homogeneous
sensitivity to brain activity, and low sensitivity to motion. A graded motor
activation protocol in 10 healthy subjects revealed that image stability was
improved by approximately 20%, by the use of phase navigator correction. As a
result, sensitivity for task-related BOLD signal change was enhanced considerably
in the brain activity maps. Implications for use of this fMRI technique in
patient studies are discussed.
PMID- 9758739
TI - Reproducibility of fMRI results across four institutions using a spatial working
memory task.
AB - Four U.S. sites formed a consortium to conduct a multisite study of fMRI methods.
The primary purpose of this consortium was to examine the reliability and
reproducibility of fMRI results. FMRI data were collected on healthy adults
during performance of a spatial working memory task at four different
institutions. Two sets of data from each institution were made available. First,
data from two subjects were made available from each site and were processed and
analyzed as a pooled data set. Second, statistical maps from five to eight
subjects per site were made available. These images were aligned in stereotactic
space and common regions of activation were examined to address the
reproducibility of fMRI results when both image acquisition and analysis vary as
a function of site. Our grouped and individual data analyses showed reliable
patterns of activation in dorsolateral prefrontal cortex and posterior parietal
cortex during performance of the working memory task across all four sites. This
multisite study, the first of its kind using fMRI data, demonstrates highly
consistent findings across sites.
PMID- 9758741
TI - Human prefrontal cortex is not specific for working memory: a functional MRI
study.
AB - Lesion studies in monkeys have provided evidence that lateral prefrontal cortex
is necessary for working memory, the cognitive processes involved in the
temporary maintenance and manipulation of information. Monkey
electrophysiological studies, however, have also observed prefrontal neuronal
activity associated with cognitive processes that are nonmnemonic. We tested the
hypothesis that the same regions of human prefrontal cortex that demonstrate
activity during working memory tasks would also demonstrate activity during tasks
without working memory demands. During echoplanar fMRI imaging, subjects
performed a three-condition experiment (working memory task, nonworking memory
task, rest). In the working memory task, subjects observed serially presented
stimuli and determined if each stimulus was the same as that presented two
stimuli back. The nonworking memory task in Experiment 1 required subjects to
identify a single predetermined stimulus; in Experiment 2, subjects were required
to make a button press to every stimulus. In all subjects in both experiments,
the working memory task exhibited greater prefrontal cortical activity compared
to either nonworking memory task. In these same prefrontal regions, greater
activation was also observed during both nonworking memory tasks compared to
rest. We conclude that human lateral prefrontal cortex supports processes in
addition to working memory. Thus, reverse inference of the form "if prefrontal
cortex is active, working memory is engaged" is not supported.
PMID- 9758740
TI - Neural correlates of memory retrieval during recognition memory and cued recall.
AB - Regional brain activity, measured by H215O PET, was investigated during
recognition memory and word-stem cued recall of words in order to compare the
neural correlates of two components of memory retrieval-effort and success-as a
function of task. For each task there was a baseline and two retrieval
conditions. In one retrieval condition (zero density), none of the test items
corresponded to words encoded in a preceding study phase. Differences in activity
between this condition and the baseline were employed to characterize the neural
correlates of retrieval effort in each task. In the other retrieval condition
(high density), 80% of the test items had been studied previously. Differences in
brain activity between this condition and the zero-density condition were taken
to represent the neural correlates of successful retrieval. The principal
findings concern the right anterior prefrontal cortex, a region demonstrated
previously to be active during episodic retrieval. Relative to baseline, this
region showed no evidence of activation in the zero-density condition of the
recognition task, but did show enhanced activity in the equivalent condition of
the cued-recall task. In contrast, relative to the zero-density condition, the
high-density condition was associated with increased right prefrontal activity
during recognition, but reduced activity during cued recall. It is proposed that
the right prefrontal cortex supports cognitive processes that operate on
information retrieved in response to a test item and that these processes
contribute to the evaluation of whether the information represents an appropriate
prior episode.
PMID- 9758742
TI - Influence of ANOVA design and anatomical standardization on statistical mapping
for PET activation.
AB - We have created images of z value, error, and variation components for a PET
activation study using various ANOVA designs and anatomical standardization
methods. Data were acquired in four PET centers. In each center, CBF was measured
on six normal male subjects under resting and covert verb generation, three times
for each. The images were anatomically standardized with LINEAR transformation,
SPM (Ver. 95), HBA (Karolinska/Tohoku), or MICHIGAN (Minoshima). ANOVA was
performed pixel by pixel to compute t (and z) for the task main effect (Verb vs
Rest) in four different designs: (i) two way (subject and task) (2W), (ii) two
way with interaction (2WI), (iii) subject considered a random factor (2WI-MX),
and (iv) three-way (subject, task, and replication) (3W). A large area extending
from the Broca to the left premotor cortex was activated. The localization of the
highest peak depended both on the anatomical standardization and on the ANOVA
design, the variation ranging 3-4 cm. Smoothing reduced the variation while
erasing possible subfoci. The z images of 2W, 2WI, and 3W looked alike, whereas
2WI-MX presented lower peak z values. SPM tended to present higher z values than
the other methods. The error was high in the gray and low in the white matter.
The root mean square for the subject effect was high on the border of gray matter
especially in LINEAR and HBA, revealing intersubject mismatch in the gray matter
distribution. The root mean square for the subject-by-task interaction effect
revealed individual variation in activation.
PMID- 9758743
TI - The inferential impact of global signal covariates in functional neuroimaging
analyses.
PMID- 9758744
TI - High-level expression of branching enzyme II from maize endosperm in Escherichia
coli.
AB - The gene that encodes the mature branching enzyme II (BEII) protein from maize
(Zea mays L.) endosperm was amplified by means of a polymerase chain reaction
technique and inserted into a T7-based expression vector. Although this has been
an efficient expression system of maize BEII in Escherichia coli, an example is
presented in this report which allows a greater expression of mBEII protein from
the bacterial system by changing only one codon. The key to the level of
expression appears to be related to the conversion of the third thymine base in
the 285 position codon of the mBEII cDNA to cytosine without altering the encoded
mBEII protein product. The crude cell extracts of enzyme prepared from E.coli
exhibited seven-fold higher expression of branching enzyme activity compared to
expression of the native enzyme. The enzymes from wild-type and the silent
mutation genes were purified. The proteins were indistinguishable kinetically and
immunologically. Thus, we obtained a significantly improved expression of mBEII
protein in the bacterial system.
PMID- 9758745
TI - Effect of promoters and signal sequences on the production of secreted HIV-1
gp120 protein in the baculovirus system.
AB - We compared insect cell production levels of secreted HIV-1 gp120 glycoprotein
encoded by five different baculovirus expression constructs. Combinations
consisting of one of two baculovirus promoters (very late or hybrid late/very
late) and one of three different signal sequences [human tissue plasminogen
activator (tpa), human placental alkaline phosphatase (pap), or baculovirus
envelope glycoprotein (gp67)] were constructed. Production of secreted gp120 from
these constructs was analyzed in two enzyme-linked immunosorbent assay formats,
one detecting the total amount of secreted gp120 protein and the other measuring
the level of "active" gp120 (as defined by the ability to bind to CD4). We found
that for all of the constructs, approximately 50 to 90% of the secreted gp120
protein was active. Furthermore, our results indicated that expression from
either promoter yielded comparable production of secreted protein, despite the
fact that transcription from the hybrid promoter begins at an earlier time. By
contrast, the signal sequence had a much greater effect on the levels of secreted
gp120: the tpa leader yielded the highest level of secreted protein, followed by
the gp67 and pap sequences. This result suggests that transcription is not a
limiting factor in the production of secreted gp120, but rather that downstream
processing of the protein is more critical. Furthermore, these results confirm
the notion that the "optimal" signal sequence is protein dependent and that an
insect-derived signal sequence is not optimal in all cases.
PMID- 9758746
TI - TolAIII co-overexpression facilitates the recovery of periplasmic recombinant
proteins into the growth medium of Escherichia coli.
AB - Overproduction of the third topological domain of the transmembrane protein TolA
(TolAIII) in the periplasm of Escherichia coli confers a "leaky" phenotype to
host cells by disrupting the integrity of the outer membrane and causing
periplasmic proteins to leach into the growth medium. To examine the
physiological consequences of TolAIII overexpression in more detail and assess
the usefulness of this strategy for the release of periplasmic recombinant
proteins into the extracellular fluid, we constructed a ColE1-compatible plasmid
encoding a fusion between the ribose binding protein signal sequence and TolAIII
under T7lac transcriptional control. About half of the total TolAIII synthesized
in IPTG-induced cells aggregated in a precursor form in the cytoplasm. However,
the majority of the mature protein was soluble and located in the extracellular
fluid. TolAIII-overproducing cultures exhibited only slight growth defects upon
entry into stationary phase but underwent extensive lysis when treated with 0.1%
(w/v) SDS, and were unable to divide when supplemented with 0.02% SDS. The loss
of outer membrane integrity resulted in long-term damage since cell viability was
reduced by three orders of magnitude compared to control or uninduced cells.
Overexpression of TolAIII did not significantly interfere with the translocation
and processing of a plasmid-encoded fusion between the OmpA signal sequence and
TEM-beta-lactamase but led to the release of most periplasmic proteins and 90% of
the active enzyme into the extracellular fluid. Although the total levels of beta
lactamase accumulation in TolAIII-overproducing cultures was only 1.5- to 2-fold
less than in control cells, the formation of periplasmic inclusions bodies was
completely suppressed. A threshold concentration of TolAIII was necessary for
efficient release of periplasmic proteins since the viability and detergent
sensitivity of uninduced cells was comparable to that of control cultures and 80%
of the beta-lactamase synthesized remained confined to the periplasm.
PMID- 9758747
TI - Purification and interfacial behavior of recombinant human gastric lipase
produced from insect cells in a bioreactor.
AB - Recombinant human gastric lipase (rHGL) (EC 3.1.1.3) was produced on a large
scale (5-13 mg/liter) from recombinant baculovirus-infected insect cells using a
bioreactor apparatus. Here an improved procedure is described for purifying rHGL
involving the use of cation exchange chromatography followed by immunoaffinity
column methods, which gives a total yield of 62% and a purification factor of
464, using 10% isopropanol in all the purification buffers. The presence of
isopropanol was necessary to preserve the stability of the enzyme during the
chromatographic separation steps. The specific activity of rHGL on
tributyroylglycerol (700 U/mg) was lower than that of native HGL (nHGL) (1080
U/mg). The rHGL interfacial adsorption kinetics were studied by recording the
changes in the surface pressure with time in the presence or absence of an egg
phosphatidycholine monomolecular film spread at the air/water interface at
various initial surface pressures. The surface behavior of rHGL was similar to
that of nHGL. It can be concluded that the lipid binding affinity of rHGL is
identical to that of the native lipase and, consequently, that the presence of
detergents and lipids in the insect cell culture media did not affect the
interfacial behavior of the purified rHGL. It will be therefore possible to
specifically study the binding step of HGL mutants to a lipid monolayer.
PMID- 9758748
TI - Recombinant human retinol-binding protein refolding, native disulfide formation,
and characterization.
AB - Human retinol-binding protein (RBP) is a monomeric 21-kDa protein that is
currently the subject of numerous studies owing to its role in the cellular
uptake and utilization of retinol. When the RBP gene is overexpressed in
Escherichia coli, inclusion bodies of aggregated RBP are found in the cells.
These inclusion bodies are solubilized in 5.0 M GdmCl containing 10 mM DTT.
Refolding of RBP is carried out in the presence of vitamin A by diluting
denatured and reduced RBP into a redox refolding buffer consisting of 3 mM
cysteine/0.3 mM cystine at 4 degreesC. Ion exchange chromatography (HPLC) is
utilized to purify refolded RBP to homogeneity as demonstrated by SDS-PAGE and
electrospray MS. The native structure of refolded RBP was established by its
ability to bind to vitamin A and the plasma protein transthyretin. The
reconstitution of RBP outlined within affords a 50-60% overall yield, i.e., 73 mg
of pure RBP/L of E. coli culture.
PMID- 9758749
TI - Production of recombinant human monocyte/neutrophil elastase inhibitor (rM/NEI).
AB - Recombinant human monocyte/neutrophil elastase inhibitor (rM/NEI) was expressed
with a baculovirus expression system. The purified recombinant protein was shown
to inhibit human neutrophil elastase by the formation of a stable equimolar
complex, as had been shown for M/NEI isolated from monocyte-derived cell lines.
rM/NEI was remarkably stable in aqueous buffers from pH 6 to pH 8, but not in
buffers below pH 6. rM/NEI activity was stable when subjected to freeze-thaw
cycles and low temperature storage in Tris or phosphate buffers. rM/NEI could
also be lyophilized without significant loss of activity. A 1.6-g batch of
greater than 95% purity in rM/NEI was obtained by anion exchange and size
exclusion chromatography with yields of 7 to 8 mg per liter of cultured insect
cells. Methods and protocols were chosen for compatibility with large-scale cGMP
production and were suitable for biochemical characterization and preclinical
evaluation of rM/NEI as a therapeutic agent for cystic fibrosis. The availability
of large amounts of purified rM/NEI will facilitate clinical evaluation of rM/NEI
for prevention of the elastase-mediated destruction of lung tissue associated
with the morbidity and mortality of cystic fibrosis.
PMID- 9758750
TI - Coexpression of G-CSF with an unglycosylated G-CSF receptor mutant results in
secretion of a stable complex.
AB - Previously, we have shown that the entire extracellular domain of the granulocyte
colony stimulating factor receptor (sG-CSFr) produced in Chinese hamster ovary
(CHO) cells forms a stable complex with its ligand G-CSF, at a stoichiometry of
2:2. A truncated receptor molecule consisting of the cytokine receptor homology
domain and N-terminus Ig-like domain (Ig CRH) behaves quite similarly. Both of
these forms of the receptor are highly glycosylated. To address the importance of
glycosylation toward receptor activity and stability, and possibly obtain
nonglycosylated receptor for crystallization, mutations were made to replace four
Asn residues which are N-glycosylated in the truncated receptor. Virtually no
receptor was recovered from conditioned media of CHO cells transfected with this
mutant construct, although a high-level of mRNA coding for receptor was detected;
this mRNA was translated as determined by Western blots of cell lysates. These
results indicate that the translated product is apparently not secreted from
these cells. Cells transfected with mutant receptor cDNA were cotransfected with
a cDNA construct expressing G-CSF in which the single O-glycosylation site was
eliminated by mutation. Upon fermentation of the cotransfectants, we observed a
large amount of receptor-ligand complex in the conditioned media. The purified
unglycosylated complex appeared to be of the same binding stoichiometry and
approximate binding affinity as that of complex formed by addition of purified
ligand and unmutated receptor. These results show that while glycosylation of sG
CSFr is not necessary for ligand binding, it appears to be crucial in folding and
export from the cell.
PMID- 9758751
TI - Expression and purification of HIV-I p15NC protein in Escherichia coli.
AB - An efficient method for the expression and purification of nucleocapsid precursor
protein (p15NC) from HIV-I (BH 10 isolate) was developed and used to obtain large
quantities of this viral protein for structural studies, protein biochemistry,
and high-throughput screening efforts. We have engineered an existing p15NC clone
into a new vector developed at the University of Heidelberg, Germany. Using PCR,
we introduced new restriction sites and a strong ribosome-binding site in the
p15NC gene and expressed authentic p15NC protein. Our protocol enabled us to
rapidly obtain soluble and highly stable p15NC expressed in Escherichia coli and
to purify several milligrams of p15NC to homogeneity. In the current purification
scheme, lysis of cell paste followed by a simple three-step FPLC procedure yields
about 0.4-0.5 mg of purified p15NC per gram of E. coli cell paste expressing the
protein with an overall yield of 45%. The purified p15NC retained its ability to
bind full-length HIV-I p15NC mRNA in solution- or solid-phase-based assays. A
specific stem-loop forming RNA fragment (24-mer) and its antisense DNA oligomer
(21-mer) derived from the full-length p15NC mRNA were also able to bind to p15NC.
In addition, antisense DNA oligos with bulky 5-iodouracil and 5-iodocytidine
substituents were able to bind to p15NC with little or no perturbations as
assessed by their ability to compete with the full-length p15NC mRNA in filter
binding competition assays. In addition, RNA-dependent cleavage of the purified
p15NC in vitro by HIV-I protease occurred at rates similar to those reported
previously.
PMID- 9758752
TI - Purification of elongation factors EF-Tu and EF-G from Escherichia coli by
covalent chromatography on thiol-sepharose.
AB - The elongation factors EF-Tu and EF-G of Escherichia coli are involved in the
transport of aminoacyl-tRNA to ribosomes and the translocation of ribosomes on
mRNA, respectively. Both possess cysteine residues that are important for
activity. We took advantage of this property to design a purification protocol
based on thiol-Sepharose chromatography, a method involving thiol-disulfide
interchange between protein thiol groups and the glutathione-2-pyridyl-disulfide
conjugate of the affinity resin. Bacterial cells were lysed by a lysozyme-EDTA
method, and the lysate supernatant was purified by chromatography on, first, DEAE
Sephacel and, then thiol-Sepharose. Both elongation factors were purified in a
single procedure, since DEAE-Sephacel fractions containing both factors were
loaded on the thiol-Sepharose column. Thiol-Sepharose chromatography efficiently
separates each elongation factor from all contaminating proteins. The purified
elongation factors were characterized by SDS-PAGE, protein sequencing, and
biological activity. The specific reactivities of the elongation factors with
thiol-Sepharose allow their efficient purification and suggest that they possess
hitherto undiscovered properties connected with their reactive thiols.
PMID- 9758754
TI - A nondenaturing purification scheme for the DNA-binding domain of poly(ADP
ribose) polymerase, a structure-specific DNA-binding protein.
AB - Poly(ADP-ribose) polymerase (PARP) is thought to be involved in DNA repair given
its ability to recognize and bind to DNA strand breaks. During apoptosis, PARP is
proteolytically cleaved into two stable fragments, the N-terminal 25-kDa DNA
binding domain (DBD) and the 85-kDa fragment containing the automodification and
catalytic domains. To understand the DNA-binding properties of PARP, we expressed
a recombinant hexahistidine tagged protein (His-DBD) in Escherichia coli. We
modified expression to facilitate protein folding by including zinc and reducing
the induction temperature. Properly folded, the DNA-binding domain of PARP binds
to single- and double-stranded DNA in a structure-specific manner. To eliminate
contamination with bacterial DNA that occurred during the purification process, a
purification procedure was developed to produce DNA-free protein. In addition, to
remove the hexahistidine tag from the recombinant protein, thrombin cleavage was
carried out while the recombinant protein was bound to a DNA column. This
procedure stabilized the recombinant protein and resulted in nearly 100% cleavage
with no appreciable loss to unwanted proteolytic degradation. This nondenaturing
purification scheme results in high-quality, native PARP-DBD for use in
structural and biochemical studies.
PMID- 9758753
TI - Facile purification of fibrinogen fragments using a computer-based model with
general applicability to the generation of salt gradients.
AB - We and others have recently shown that specific fragments of cross-linked fibrin
affect cell behavior. In order to develop a facile method for the preparative
scale purification of fibrin fragment D dimer, a simple gradient generating
system for conventional chromatography was developed and validated, and methods
of fibrin fragment D dimer purification were compared. The experimentally
measured salt concentration/time relationship fell directly on the model
predicted line. Model-predicted changes in the reservoir volume and/or salt
concentration in the limit buffer affected both the initial slope and the shape
of the concentration/time relationship. This gradient generation method was used
to separate the D domains of fibrin(ogen) from the amino terminal region E domain
using anion-exchange chromatography. While the predicted salt gradient was
achieved, a salt-dependent separation was found to be less optimal than that of a
pH-dependent separation, as validated by Coomassie-stained SDS-PAGE and by
immunoblotting. In conclusion, a facile, user-friendly, computer-based method to
predict and generate salt gradients was written and validated by direct
experimentation. While fibrinogen fragment purification was acceptable using this
system, both separation and yields of fibrinogen and fibrin fragments were
superior using a pH-based separation technique.
PMID- 9758755
TI - The chloroplast small heat shock protein--purification and characterization of
pea recombinant protein.
AB - We report here on a procedure to obtain large amounts of a chloroplast-localized
heat shock protein (HSP21) with unknown structure and function, by using an
Escherichia coli expression system for the pea (Pisum sativum) protein and a
purification procedure based on perfusion ion-exchange chromatography. After
initial precipitation steps, the sample was applied to cation- and anion-exchange
on two columns connected in sequence, which allowed rapid purification of HSP21
in one equilibration and one elution step. The purified recombinant protein had
an isoelectric point of 5. 0 and appeared in assembled, oligomeric form
(approximately 200 kDa) composed of 21-kDa monomers, similar to the native HSP21
protein as detected by immunoblotting in plants after heat-stress treatment. This
chloroplast-localized heat shock protein belongs to a special group of small heat
shock proteins (sHSPs), which share an evolutionary conserved C-terminal domain
with the vertebrate eye lens alpha-crystallin. The crystallins are known from
both crystallographic and spectroscopic data to be all-beta proteins. In
contrast, this paper presents circular dichroism spectroscopy data which shows
that the purified recombinant HSP21 oligomer has a content of more than 30% alpha
helical secondary structure.
PMID- 9758756
TI - Isotopically labeled bovine beta-lactoglobulin for NMR studies expressed in
Pichia pastoris.
AB - beta-Lactoglobulin (beta-Lg) is the major whey protein in ruminant milk and has
been implicated in the irreversible denaturation of milk proteins and its
associated poor processing behavior during heat treatment. In order to help
understand this behavior, as well as to facilitate other studies into the
relationship between the molecular structure and its behavior in solution, we
have prepared and purified 15N-labeled and 13C/15N-double-labelled beta-Lg in
sufficient quantities to permit a full determination of the structure and
dynamics using heteronuclear NMR spectroscopy. The overexpression of the labeled
protein using the Pichia pastoris system proceeds with good yield but requires
the removal of significant quantities of copurifying carbohydrate which otherwise
interfere with the NMR experiments. At pH 2, the resulting material gives triple
resonance NMR spectra of good quality that are consistent with a monomeric,
globular protein rich in beta-sheet.
PMID- 9758757
TI - Expression, purification, and characterization of recombinant ribulose-1,5
bisphosphate carboxylase/oxygenase large subunit nepsilon-methyltransferase.
AB - Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit (LS)
Nepsilon-methyltransferase (Rubisco LSMT, EC 2.1.1.127) catalyzes methylation of
the LS of Rubisco. A pea (Pisum sativum L. cv Laxton's Progress No. 9) Rubisco
LSMT cDNA was expressed in Escherichia coli, but most of the expressed protein
was found in the insoluble fraction as an inclusion body. Expression at lower
temperatures increased the level of soluble Rubisco LSMT and the associated
enzymatic activity. However, the soluble form of Rubisco LSMT occurred as two
molecular mass forms with the lower molecular mass suggestive of N-terminal
processing at Ser-37. Deletion of 108 nucleotides from the 5' end encoding the N
terminal 36 amino acids of Rubisco LSMT resulted in a 10-fold increase in
solubility and activity. Further addition of a 3' nucleotide sequence coding for
a hexahistidyl carboxy-terminal peptide enabled purification of the N-terminally
truncated Rubisco LSMT to homogeneity. Five milligrams of pure recombinant
Rubisco LSMT was obtained from a 1-liter E. coli cell culture. The apparent
kinetic constants for recombinant Rubisco LSMT for spinach Rubisco and AdoMet
were only slightly different from the constants determined using affinity
purified native Rubisco LSMT from pea chloroplasts. However, there was a 6- to 7
fold reduction in the kcat for Rubisco LSMT, which was apparently a consequence
of catalytic inactivation due to exposure to NiSO4 during purification. The
availability of larger quantities of purified Rubisco LSMT should enable studies
of the structure-function relationships in Rubisco LSMT and moreover its
interaction with Rubisco.
PMID- 9758758
TI - Design of protein purification pathways: application to the proteome of
Haemophilus influenzae using heparin chromatography.
AB - The design of efficient protein purification protocols is a scientific challenge
and can be facilitated by the use of master protein enrichment or purification
steps. A master purification step is in principle a list including the major
proteins expected to be present in the various fractions collected from a
particular enrichment process. Consideration of a master step in the design of a
purification pathway can reduce the time and effort usually invested in "trial
and error" approaches. Moreover, master purification steps will certainly become
valuable tools in the isolation of proteins today designated as hypothetical or
predicted coding regions, resulting from the sequencing of the various genomes,
and for which no information on their purification exists. The construction of
such a master step consists of performance of the protein separation by the
particular chromatographic method, analysis by two-dimensional polyacrylamide gel
electrophoresis, and identification by mass spectrometry of the proteins present
in each fraction. This can be efficiently accomplished now thanks to developments
in two-dimensional gel technology and large-scale sample throughput mass
spectrometry. Here we present an example of construction of a master protein
enrichment step using the soluble protein fraction of the bacterium Haemophilus
influenzae and applying Heparin chromatography.
PMID- 9758759
TI - Expression and ligand binding assays of soluble cytokine receptor-immunoglobulin
fusion proteins.
AB - We have developed a cloning vector for the expression of type I cytokine
receptor, NO, extracellular domain (ECD)-mouse IgG1 Fc fusion proteins. The
vector has a versatile polylinker that allows in-frame cloning of the receptor
ECD with the mouse IgG1 sequence to encode a receptor ECD-IgG1 fusion construct.
The receptor-IgG1 fusion proteins are transiently expressed in useful amounts
following transfection of the expression vector into COS7 cells and G418
selection. The mouse IgG1 portion of the fusion protein provides a universal
handle for purification on an affinity matrix and detection by anti-mouse IgG
antibodies in ELISA or Western blot formats. The expressed receptor ECD-IgG1
fusion proteins bind their cognate ligands. In order to demonstrate that the
fusion proteins have similar ligand binding affinities as the native receptors,
the affinity constants (Kd) for EPOR, TNFR, IL-4R, and IL-6R-IgG1 fusion proteins
were measured by surface plasmon resonance and shown to be in good agreement with
published values. The TNFR-IgG1 fusion protein was employed in a demonstration of
a novel ELISA format for detecting cytokine receptor binding to cytokine.
PMID- 9758760
TI - Purification and characterization of a soybean root nodule phosphatase expressed
in Pichia pastoris.
AB - Soybean root nodules possess a developmentally regulated acid phosphatase (ACP)
that exhibits the highest specificity for purine 5'-nucleoside monophosphates.
The enzyme is a glycosylated dimer of 28- and 31-kDa subunits, which appear to be
products of the same gene but differ in posttranslational modifications. In order
to perform directed mutagenesis and more extensive biochemical characterization,
a means of producing recombinant ACP was needed. Several attempts were made to
express ACP in Escherichia coli, but all conditions employed resulted in protein
that was found entirely in inclusion bodies, and resolubilization experiments
were unsuccessful. Therefore, the methyltrophic yeast Pichia pastoris was chosen
as a eukaryotic expression host. The coding sequence of ACP was cloned into the
pPIC9 vector to create a fusion with the yeast alpha mating factor secretion
signal. The ACP:pPIC9 construct was integrated into P. pastoris strain GS115.
Expression of ACP was under the control of an alcohol oxidase methanol-inducible
promoter. Methanol induction resulted in secretion of ACP to a level of 10 mg/L.
The recombinant ACP was purified 550-fold to homogeneity by phenyl-Sepharose,
hydroxyapatite, and MonoS chromatography. The purified enzyme had Km values of
0.08 and 0.12 for 5'-AMP and 5'-GMP. These values were similar to those obtained
for the native ACP heterodimer purified from soybean (0.08 and 0.15 mM for 5'-AMP
and 5'-GMP). The specific activity of the recombinant enzyme for all substrates
tested was 1.6- to 1.8-fold higher than the values for the purified soybean
heterodimer.
PMID- 9758761
TI - Cloning and expression in Escherichia coli of the recombinant his-tagged DNA
polymerases from Pyrococcus furiosus and Pyrococcus woesei.
AB - Complete PCR-derived DNA fragments containing the structural genes for DNA
polymerases of the archaeons Pyrococcus furiosus and Pyrococcus woesei were
cloned into an expression vector. The clones expressing thermostable His-tagged
DNA polymerases were selected. The cloned fragments were sequenced. The DNA
sequences were verified to be authentic by sequencing several clones. The
nucleotide (nt) sequence revealed that DNA polymerase of P. woesei (Pwo DNA
polymerase) consists of 775 amino acids and has a molecular weight of 90,566. It
shows 100% nucleotide identity to the nucleotide sequence of DNA polymerase from
P. furiosus (Pfu DNA polymerase). The results confirm that nucleotide sequences
of both archaeons (P. furiosus and P. woesei) are highly similar. The recombinant
DNA polymerases (His-tagged Pfu and His-tagged Pwo) contained a polyhistidine tag
at the N-terminus (43 additional amino acids) that allowed single-step isolation
by Ni-affinity chromatography. We found that recombinant plasmids are toxic or
unstable in the expressing strain BL21(DE3), even in the absence of the inducing
agent, IPTG. However, the plasmids were stable in BL21(DE3) containing the pLysS
plasmid, which suppresses expression prior to induction, and His-tagged proteins
were expressed upon IPTG addition. The proteins were purified by heat treatment
(to denature E. coli proteins), followed by metal-affinity chromatography on Ni2+
Sepharose columns. The enzymes were characterized and displayed high DNA
polymerase activity and thermostability. This bacterial expression system appears
to be the method of choice for production of Pfu or Pwo DNA polymerases.
PMID- 9758764
TI - Volume 13, number 2 (1998), in article no. PT980898, "Bacterial expression and
characterization of human recombinant apolipoprotein(a) kringle IV type 9," by Fu
Zon chung, lan-hsin wu, helen T. Lee, william T. Mueller, mark A. Spahr, scott R.
Eaton, Ye tian, philip D. Settimi, dale L. Oxender, and randy ramharack, pages
222-228:
PMID- 9758762
TI - Purification of active chloroplast sedoheptulose-1,7-bisphosphatase expressed in
Escherichia coli.
AB - Sedoheptulose-1,7-bisphosphatase (SBPase) is an enzyme unique to photosynthetic
organisms and has a key role in regulating the photosynthetic Calvin cycle
through which nearly all carbon enters the biosphere. This makes SBPase an
appropriate target for intensive study. We have expressed wheat SBPase in
Escherichia coli either with or without an N-terminal polyhistidine tag. The
identity of the recombinant SBPases was confirmed by SDS-PAGE analysis and
immunological detection with a specific antibody. Recombinant SBPase with a
polyhistidine tag (His-SBPase) was obtained in soluble, active form and purified
by one-step metal-chelate chromatography. Like the native enzyme, recombinant His
SBPase was specific for the substrate sedoheptulose-1,7-bisphosphate and required
the presence of a reducing agent for activity. Polyclonal antibodies were raised
against recombinant SBPase and were then used to determine relative levels of the
enzyme in plant extracts. The availability of large amounts of active recombinant
SBPase will also allow detailed structural studies by site-directed mutagenesis
and X-ray crystallography.
PMID- 9758763
TI - Overexpression of functional hydrolase domain of rat liver 10
formyltetrahydrofolate dehydrogenase in Escherichia coli.
AB - Rat liver 10-formyltetrahydrofolate dehydrogenase (FDH) is a tetrameric enzyme
composed of four identical 902-amino-acid-residue (99 kDa) monomers. We expressed
the enzyme and its 310-amino-acid-residue amino-terminal domain, which is 10
formyltetrahydrofolate hydrolase, in Escherichia coli BL21 (DE3) cells using the
pRSET expression vector. We removed the entire translated region of the vector
including the polyhistidyl tag and the recombinant proteins were expressed, not
as a fusion constructs, but as unmodified sequences. The expressed full-length
enzyme was found to be an insoluble protein and was not purified and
characterized, while the amino-terminal domain was expressed as a soluble protein
possessing hydrolase activity. The recombinant amino-terminal domain was purified
in one step on a DEAE MemSep 1000 HP Ion-Exchange Membrane Chromatography
Cartridge (Millipore) using a ConSep LC100 chromatographic system (Millipore).
The chromatography gave a homogenous and active preparation of the recombinant
protein with a yield of about 2 mg per 100 ml of bacterial culture. Kinetic
parameters of the hydrolase reaction displayed by the amino-terminal domain
expressed in E. coli were similar to those of the recombinant full-length enzyme
and its amino-terminal domain previously expressed in insect cells. The purified
recombinant enzyme remained active for at least 4 weeks at 4 degreesC. These
results show that the hydrolase amino-terminal domain of FDH can be overexpressed
as a functional enzyme in E. coli cells and purified in one step by a simple
chromatographic procedure.
PMID- 9758766
TI - c-type cytochromes and manganese oxidation in Pseudomonas putida MnB1.
AB - Pseudomonas putida MnB1 is an isolate from an Mn oxide-encrusted pipeline that
can oxidize Mn(II) to Mn oxides. We used transposon mutagenesis to construct
mutants of strain MnB1 that are unable to oxidize manganese, and we characterized
some of these mutants. The mutants were divided into three groups: mutants
defective in the biogenesis of c-type cytochromes, mutants defective in genes
that encode key enzymes of the tricarboxylic acid cycle, and mutants defective in
the biosynthesis of tryptophan. The mutants in the first two groups were
cytochrome c oxidase negative and did not contain c-type cytochromes. Mn(II)
oxidation capability could be recovered in a c-type cytochrome biogenesis
defective mutant by complementation of the mutation.
PMID- 9758767
TI - The cytochrome c maturation operon is involved in manganese oxidation in
Pseudomonas putida GB-1.
AB - A Pseudomonas putida strain, strain GB-1, oxidizes Mn2+ to Mn oxide in the early
stationary growth phase. It also secretes a siderophore (identified as
pyoverdine) when it is subjected to iron limitation. After transposon (Tn5)
mutagenesis several classes of mutants with differences in Mn2+ oxidation and/or
secretion of the Mn2+-oxidizing activity were identified. Preliminary analysis of
the Tn5 insertion site in one of the nonoxidizing mutants suggested that a
multicopper oxidase-related enzyme is involved in Mn2+ oxidation. The insertion
site in another mutant was preliminarily identified as a gene involved in the
general protein secretion pathway. Two mutants defective in Mn2+-oxidizing
activity also secreted porphyrins into the medium and appeared to be derepressed
for pyoverdine production. These strains were chosen for detailed analysis. Both
mutants were shown to contain Tn5 insertions in the ccmF gene, which is part of
the cytochrome c maturation operon. They were cytochrome oxidase negative and did
not contain c-type cytochromes. Complementation with part of the ccm operon
isolated from the wild type restored the phenotype of the parent strain. These
results indicate that a functional ccm operon is required for Mn2+ oxidation in
P. putida GB-1. A possible relationship between porphyrin secretion resulting
from the ccm mutation and stimulation of pyoverdine production is discussed.
PMID- 9758768
TI - Secondary metabolite- and endochitinase-dependent antagonism toward plant
pathogenic microfungi of pseudomonas fluorescens isolates from sugar beet
rhizosphere
AB - Forty-seven isolates representing all biovars of Pseudomonas fluorescens (biovars
I to VI) were collected from the rhizosphere of field-grown sugar beet plants to
select candidate strains for biological control of preemergence damping-off
disease. The isolates were tested for in vitro antagonism toward the plant
pathogenic microfungi Pythium ultimum and Rhizoctonia solani in three different
plate test media. Mechanisms of fungal inhibition were elucidated by tracing
secondary-metabolite production and cell wall-degrading enzyme activity in the
same media. Most biovars expressed a specific mechanism of antagonism, as
represented by a unique antibiotic or enzyme production in the media. A
lipopeptide antibiotic, viscosinamide, was produced independently of medium
composition by P. fluorescens bv. I, whereas the antibiotic 2, 4
diacetylphloroglucinol was observed only in glucose-rich medium and only in P.
fluorescens bv. II/IV. Both pathogens were inhibited by the two antibiotics.
Finally, in low-glucose medium, a cell wall-degrading endochitinase activity in
P. fluorescens bv. I, III, and VI was the apparent mechanism of antagonism toward
R. solani. The viscosinamide-producing DR54 isolate (bv. I) was shown to be an
effective candidate for biological control, as tested in a pot experiment with
sugar beet seedlings infested with Pythium ultimum. The assignment of different
patterns of fungal antagonism to the biovars of P. fluorescens is discussed in
relation to an improved selection protocol for candidate strains to be used in
biological control.
PMID- 9758769
TI - Leaching of zinc sulfide by thiobacillus ferrooxidans: experiments with a
controlled redox potential indicate No direct bacterial mechanism
AB - The role of Thiobacillus ferrooxidans in bacterial leaching of mineral sulfides
is controversial. Much of the controversy is due to the fact that the solution
conditions, especially the concentrations of ferric and ferrous ions, change
during experiments. The role of the bacteria would be more easily discernible if
the concentrations of ferric and ferrous ions were maintained at set values
throughout the experimental period. In this paper we report results obtained by
using the constant redox potential apparatus described previously (P. I. Harvey
and F. K. Crundwell, Appl. Environ. Microbiol. 63:2586-2592, 1997). This
apparatus is designed to control the redox potential in the leaching compartment
of an electrolytic cell by reduction or oxidation of dissolved iron. By
controlling the redox potential the apparatus maintains the concentrations of
ferrous and ferric ions at their initial values. Experiments were conducted in
the presence of T. ferrooxidans and under sterile conditions. Analysis of the
conversion of zinc sulfide in the absence of the bacteria and analysis of the
conversion of zinc sulfate in the presence of the bacteria produced the same
results. This indicates that the only role of the bacteria under the conditions
used is regeneration of ferric ions in solution. In this work we found no
evidence that there is a direct mechanism for bacterial leaching.
PMID- 9758770
TI - Thermocrinis ruber gen. nov., sp. nov., A pink-filament-forming hyperthermophilic
bacterium isolated from yellowstone national park
AB - A novel hyperthermophilic bacterium was isolated from pink filamentous streamers
(pink filaments) occurring in the upper outflow channel (temperature, 82 to 88
degreesC) of Octopus Spring in Yellowstone National Park, Wyo. The gram-negative
cells grew at low salinity at temperatures up to 89 degreesC in the neutral to
alkaline pH range. Depending on the culture conditions, the organisms occurred as
single motile rods, as aggregates, or as long filaments that formed streamer-like
cell masses. The novel isolate grew chemolithoautotrophically with hydrogen,
thiosulfate, and elemental sulfur as electron donors and oxygen as the electron
acceptor. Alternatively, under aerobic conditions, formate and formamide served
as sole energy and carbon sources. The novel isolate had a 16S rRNA sequence
closely related to the 16S rRNA sequence obtained from uncultivated pink
filaments. It represents a new genus in the order Aquificales, the type species
of which we name Thermocrinis ruber (type strain, OC 1/4 [= DSM 12173]).
PMID- 9758771
TI - Effects of pH and oxygen and ammonium concentrations on the community structure
of nitrifying bacteria from wastewater
AB - Shifts in nitrifying community structure and function in response to different
ammonium concentrations (50, 500, 1,000, and 3,000 mg of N liter-1), pH values
(pH 6.0, 7.0, and 8.2), and oxygen concentrations (1, 7, and 21%) were studied in
experimental reactors inoculated with nitrifying bacteria from a wastewater
treatment plant. The abilities of the communities selected for these conditions
to regain their original structures after conditions were returned to the
original conditions were also determined. Changes in nitrifying community
structure were determined by performing an amplified ribosomal DNA (rDNA)
restriction analysis of PCR products obtained with ammonia oxidizer-specific rDNA
primers, by phylogenetic probing, by small-subunit (SSU) rDNA sequencing, and by
performing a cellular fatty acid analysis. Digestion of ammonia-oxidizer SSU rDNA
with five restriction enzymes showed that a high ammonium level resulted in a
great community structure change that was reversible once the ammonium
concentration was returned to its original level. The smaller changes in
community structure brought about by the two pH extremes, however, were
irreversible. Sequence analysis revealed that the highest ammonium environment
stimulated growth of a nitrifier strain that exhibited 92.6% similarity in a
partial SSU rRNA sequence to its nearest relative, Nitrosomonas eutropha C-91,
although the PCR product did not hybridize with a general phylogenetic probe for
ammonia oxidizers belonging to the beta subgroup of the class Proteobacteria. A
principal-component analysis of fatty acid methyl ester data detected changes
from the starter culture in all communities under the new selective conditions,
but after the standard conditions were restored, all communities produced the
original fatty acid profiles.
PMID- 9758772
TI - Effects of temperature, salinity, and medium composition on compatible solute
accumulation by thermococcus spp
AB - The effects of salinity and growth temperature on the accumulation of
intracellular organic solutes were examined by nuclear magnetic resonance
spectroscopy (NMR) in Thermococcus litoralis, Thermococcus celer, Thermococcus
stetteri, and Thermococcus zilligii (strain AN1). In addition, the effects of
growth stage and composition of the medium were studied in T. litoralis. A novel
compound identified as beta-galactopyranosyl-5-hydroxylysine was detected in T.
litoralis grown on peptone-containing medium. Besides this newly discovered
compound, T. litoralis accumulated mannosylglycerate, aspartate, alpha-glutamate,
di-myo-inositol-1,1'(3,3')-phosphate, hydroxyproline, and trehalose. The
hydroxyproline and beta-galactopyranosyl-5-hydroxylysine were probably derived
from peptone, while the trehalose was derived from yeast extract; none of these
three compounds was detected in the other Thermococcus strains examined. Di-myo
inositol-1,1'(3,3')-phosphate, aspartate, and mannosylglycerate were detected in
T. celer and T. stetteri, and the latter organism also accumulated alpha
glutamate. The only nonmarine species studied, T. zilligii, accumulated very low
levels of alpha-glutamate and aspartate. The levels of mannosylglycerate and
aspartate increased in T. litoralis, T. celer, and T. stetteri in response to
salt stress, while di-myo-inositol-1,1'(3,3')-phosphate was the major
intracellular solute at supraoptimal growth temperatures. The phase of growth had
a strong influence on the types and levels of compatible solutes in T. litoralis;
mannosylglycerate and aspartate were the major solutes during exponential growth,
while di-myo-inositol-1,1'(3,3')-phosphate was the predominant organic solute
during the stationary phase of growth. This work revealed an unexpected ability
of T. litoralis to scavenge suitable components from the medium and to use them
as compatible solutes.
PMID- 9758773
TI - Two intracellular symbiotic bacteria from the mulberry psyllid Anomoneura mori
(Insecta, Homoptera).
AB - We characterized the intracellular symbiotic bacteria of the mulberry psyllid
Anomoneura mori by performing a molecular phylogenetic analysis combined with in
situ hybridization. In its abdomen, the psyllid has a large, yellow, bilobed
mycetome (or bacteriome) which consists of many round uninucleated mycetocytes
(or bacteriocytes) enclosing syncytial tissue. The mycetocytes and syncytium
harbor specific intracellular bacteria, the X-symbionts and Y-symbionts,
respectively. Almost the entire length of the bacterial 16S ribosomal DNA (rDNA)
was amplified and cloned from the whole DNA of A. mori, and two clones, the A
type and B-type clones, were identified by restriction fragment length
polymorphism analysis. In situ hybridization with specific oligonucleotide probes
demonstrated that the A-type and B-type 16S rDNAs were derived from the X
symbionts and Y-symbionts, respectively. Molecular phylogenetic analyses of the
16S rDNA sequences showed that these symbionts belong to distinct lineages in the
gamma subdivision of the Proteobacteria. No 16S rDNA sequences in the databases
were closely related to the 16S rDNA sequences of the X- and Y-symbionts.
However, the sequences that were relatively closely related to them were the
sequences of endosymbionts of other insects. The nucleotide compositions of the
16S rDNAs of the X- and Y-symbionts were highly AT biased, and the sequence of
the X-symbiont was the most AT-rich bacterial 16S rDNA sequence reported so far.
PMID- 9758774
TI - Purification, characterization, and substrate specificity of a novel highly
glucose-tolerant beta-glucosidase from Aspergillus oryzae.
AB - Aspergillus oryzae was found to secrete two distinct beta-glucosidases when it
was grown in liquid culture on various substrates. The major form had a molecular
mass of 130 kDa and was highly inhibited by glucose. The minor form, which was
induced most effectively on quercetin (3,3',4',5,7-pentahydroxyflavone)-rich
medium, represented no more than 18% of total beta-glucosidase activity but
exhibited a high tolerance to glucose inhibition. This highly glucose-tolerant
beta-glucosidase (designated HGT-BG) was purified to homogeneity by ammonium
sulfate precipitation, gel filtration, and anion-exchange chromatography. HGT-BG
is a monomeric protein with an apparent molecular mass of 43 kDa and a pI of 4.2
as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and
isoelectric focusing polyacrylamide gel electrophoresis, respectively. Using p
nitrophenyl-beta-D-glucoside as the substrate, we found that the enzyme was
optimally active at 50 degreesC and pH 5.0 and had a specific activity of 1,066
micromol min-1 mg of protein-1 and a Km of 0.55 mM under these conditions. The
enzyme is particularly resistant to inhibition by glucose (Ki, 1. 36 M) or
glucono-delta-lactone (Ki, 12.5 mM), another powerful beta-glucosidase inhibitor
present in wine. A comparison of the enzyme activities on various glycosidic
substrates indicated that HGT-BG is a broad-specificity type of fungal beta
glucosidase. It exhibits exoglucanase activity and hydrolyzes (1-->3)- and (1-
>6)-beta-glucosidic linkages most effectively. This enzyme was able to release
flavor compounds, such as geraniol, nerol, and linalol, from the corresponding
monoterpenyl-beta-D-glucosides in a grape must (pH 2.9, 90 g of glucose liter-1).
Other flavor precursors (benzyl- and 2-phenylethyl-beta-D-glucosides) and prunin
(4',5,7-trihydroxyflavanone-7-glucoside), which contribute to the bitterness of
citrus juices, are also substrates of the enzyme. Thus, this novel beta
glucosidase is of great potential interest in wine and fruit juice processing
because it releases aromatic compounds from flavorless glucosidic precursors.
PMID- 9758775
TI - The transcriptional activator XlnR regulates both xylanolytic and endoglucanase
gene expression in Aspergillus niger.
AB - The expression of genes encoding enzymes involved in xylan degradation and two
endoglucanases involved in cellulose degradation was studied at the mRNA level in
the filamentous fungus Aspergillus niger. A strain with a loss-of-function
mutation in the xlnR gene encoding the transcriptional activator XlnR and a
strain with multiple copies of this gene were investigated in order to define
which genes are controlled by XlnR. The data presented in this paper show that
the transcriptional activator XlnR regulates the transcription of the xlnB, xlnC,
and xlnD genes encoding the main xylanolytic enzymes (endoxylanases B and C and
beta-xylosidase, respectively). Also, the transcription of the genes encoding the
accessory enzymes involved in xylan degradation, including alpha-glucuronidase A,
acetylxylan esterase A, arabinoxylan arabinofuranohydrolase A, and feruloyl
esterase A, was found to be controlled by XlnR. In addition, XlnR also activates
transcription of two endoglucanase-encoding genes, eglA and eglB, indicating that
transcriptional regulation by XlnR goes beyond the genes encoding xylanolytic
enzymes and includes regulation of two endoglucanase-encoding genes.
PMID- 9758776
TI - Study of toxin production by isolates of Stachybotrys chartarum and Memnoniella
echinata isolated during a study of pulmonary hemosiderosis in infants.
AB - A cluster of cases of pulmonary hemosiderosis among infants was reported in
Cleveland, Ohio, during 1993 and 1994. These unusual cases appeared only in
infants ranging in age from 1 to 8 months and were characterized by pulmonary
hemorrhage, which caused the babies to cough up blood. A case-control study
identified major home water damage (from plumbing leaks, roof leaks, or flooding)
as a risk factor for development of pulmonary hemorrhage in these infants.
Because of an interest in the possibility that trichothecene mycotoxins might be
involved in this illness, a number of isolates of Stachybotrys chartarum were
grown in the laboratory on rice, and extracts were prepared and analyzed both for
cytotoxicity and for specific toxins. Two isolates of Memnoniella echinata, a
fungus closely related to S. chartarum, were also included in these studies. S.
chartarum isolates collected from the homes were shown to produce a number of
highly toxic compounds, and the profiles of toxic compounds from M. echinata were
similar; the most notable difference was the fact that the principal metabolites
produced by M. echinata were griseofulvins.
PMID- 9758777
TI - Analysis of the gene cluster encoding toluene/o-xylene monooxygenase from
Pseudomonas stutzeri OX1.
AB - The toluene/o-xylene monooxygenase cloned from Pseudomonas stutzeri OX1 displays
a very broad range of substrates and a very peculiar regioselectivity, because it
is able to hydroxylate more than one position on the aromatic ring of several
hydrocarbons and phenols. The nucleotide sequence of the gene cluster coding for
this enzymatic system has been determined. The sequence analysis revealed the
presence of six open reading frames (ORFs) homologous to other genes clustered in
operons coding for multicomponent monooxygenases found in benzene- and toluene
degradative pathways cloned from Pseudomonas strains. Significant similarities
were also found with multicomponent monooxygenase systems for phenol, methane,
alkene, and dimethyl sulfide cloned from different bacterial strains. The
knockout of each ORF and complementation with the wild-type allele indicated that
all six ORFs are essential for the full activity of the toluene/o-xylene
monooxygenase in Escherichia coli. This analysis also shows that despite its
activity on both hydrocarbons and phenols, toluene/ o-xylene monooxygenase
belongs to a toluene multicomponent monooxygenase subfamily rather than to the
monooxygenases active on phenols.
PMID- 9758779
TI - Intracellular changes in ions and organic solutes in halotolerant brevibacterium
sp. Strain JCM 6894 after exposure to hyperosmotic shock
AB - In the present study we aimed to observe the intracellular responses when there
was a hyperosmotic shock with a large shift in ionic strength in nutrient-rich
and nutrient-poor external environments in order to clarify the availability of
substrates. To do this, we used the halotolerant organism Brevibacterium sp.
strain JCM 6894, which is able to grow in the presence of a wide range of salt
concentrations. Hyperosmotic shock was induced by transferring cells in the late
exponential phase of growth in a complex medium containing 0.5 M NaCl into either
old or fresh culture medium containing 2 M NaCl. Changes in the growth rate, in
the pH of the medium, and in the internal cation or organic solute concentrations
in the cytosol after an upshock were analyzed as a function of incubation time.
The cells exhibited very different responses to upshocks in fresh culture medium
and in old culture medium; in fresh culture medium, growth was stimulated and the
medium became more acidic, whereas the old culture medium repressed growth and
the medium became more alkaline. The intracellular free Na+ concentrations
remained low (80 nmol mg of protein-1) after an upshock in fresh culture medium,
although they quickly increased twofold in the old culture medium. In contrast,
K+ ions immediately accumulated in the cells in fresh culture medium, whereas K+
ions were taken up quite slowly in old culture medium. Furthermore, the cells
placed in fresh culture medium transiently accumulated alanine and glutamine in
response to the upshock, but the cells placed in old culture medium did not.
Growth of the Brevibacterium strain at higher levels of salinity was supported by
ectoine synthesis but was not observed after the shift to high-osmolarity
conditions in the old culture. In the fresh culture, however, ectoine was
vigorously synthesized in cells for more than 5 h after the upshock; the
concentration of ectoine in cells was more than 3,500 nmol mg of protein-1 at 10
h, which corresponded to a ninefold increase compared to the concentration before
the shock. These findings are consistent with the results of an analysis of the
extracellular medium composition before and after the upshock.
PMID- 9758778
TI - Plasmids responsible for horizontal transfer of naphthalene catabolism genes
between bacteria at a coal tar-contaminated site are homologous to pDTG1 from
pseudomonas putida NCIB 9816-4
AB - The presence of a highly conserved nahAc allele among phylogenetically diverse
bacteria carrying naphthalene-catabolic plasmids provided evidence for in situ
horizontal gene transfer at a coal tar-contaminated site (J. B. Herrick, K. G.
Stuart-Keil, W. C. Ghiorse, and E. L. Madsen, Appl. Environ. Microbiol. 63:2330
2337, 1997). The objective of the present study was to identify and characterize
the different-sized naphthalene-catabolic plasmids in order to determine the
probable mechanism of horizontal transfer of the nahAc gene in situ. Filter
matings between naphthalene-degrading bacterial isolates and their cured progeny
revealed that the naphthalene-catabolic plasmids were self-transmissible. Limited
interstrain transfer was also found. Analysis of the restriction fragment length
polymorphism (RFLP) patterns indicated that catabolic plasmids from 12 site
derived isolates were closely related to each other and to the naphthalene
catabolic plasmid (pDTG1) of Pseudomonas putida NCIB 9816-4, which was isolated
decades ago in Bangor, Wales. The similarity among all site-derived naphthalene
catabolic plasmids and pDTG1 was confirmed by using the entire pDTG1 plasmid as a
probe in Southern hybridizations. Two distinct but similar naphthalene-catabolic
plasmids were retrieved directly from the microbial community indigenous to the
contaminated site in a filter mating by using a cured, rifampin-resistant site
derived isolate as the recipient. RFLP patterns and Southern hybridization showed
that both of these newly retrieved plasmids, like the isolate-derived plasmids,
were closely related to pDTG1. These data indicate that a pDTG1-like plasmid is
the mobile genetic element responsible for transferring naphthalene-catabolic
genes among bacteria in situ. The pervasiveness and persistence of this
naphthalene-catabolic plasmid suggest that it may have played a role in the
adaptation of this microbial community to the coal tar contamination at our study
site.
PMID- 9758780
TI - Vibrio cholerae O1 strain TSI-4 produces the exopolysaccharide materials that
determine colony morphology, stress resistance, and biofilm formation.
AB - Vibrio cholerae O1 strain TSI-4 (El Tor, Ogawa) can shift to a rugose colony
morphology from its normal translucent colony morphology in response to nutrient
starvation. We have investigated differences between the rugose and translucent
forms of V. cholerae O1 strain TSI-4. Electron microscopic examination of the
rugose form of TSI-4 (TSI-4/R) revealed thick, electron-dense exopolysaccharide
materials surrounding polycationic ferritin-stained cells, while the ferritin
stained material was absent around the translucent form of TSI-4 (TSI-4/T). The
exopolysaccharide produced by V. cholerae TSI-4/R was found to have a composition
of N-acetyl-D-glucosamine, D-mannose, 6-deoxy-D-galactose, and D-galactose
(7.4:10.2:2.4:3.0). The expression of an amorphous exopolysaccharide promotes
biofilm development under static culture conditions. Biofilm formation by the
rugose strain was determined by scanning electron microscopy, and most of the
surface of the film was colonized by actively dividing rod cells. The
corresponding rugose and translucent strains were compared for stress resistance.
By having exopolysaccharide materials, the rugose strains acquired resistance to
osmotic and oxidative stress. Our data indicated that an exopolysaccharide
material on the surface of the rugose strain promoted biofilm formation and
resistance to the effects of two stressing agents.
PMID- 9758782
TI - A plant growth-promoting bacterium that decreases nickel toxicity in seedlings
AB - A plant growth-promoting bacterium, Kluyvera ascorbata SUD165, that contained
high levels of heavy metals was isolated from soil collected near Sudbury,
Ontario, Canada. The bacterium was resistant to the toxic effects of Ni2+, Pb2+,
Zn2+, and CrO4-, produced a siderophore(s), and displayed 1-aminocyclopropane-1
carboxylic acid deaminase activity. Canola seeds inoculated with this bacterium
and then grown under gnotobiotic conditions in the presence of high
concentrations of nickel chloride were partially protected against nickel
toxicity. In addition, protection by the bacterium against nickel toxicity was
evident in pot experiments with canola and tomato seeds. The presence of K.
ascorbata SUD165 had no measurable influence on the amount of nickel accumulated
per milligram (dry weight) of either roots or shoots of canola plants. Therefore,
the bacterial plant growth-promoting effect in the presence of nickel was
probably not attributable to the reduction of nickel uptake by seedlings. Rather,
it may reflect the ability of the bacterium to lower the level of stress ethylene
induced by the nickel.
PMID- 9758781
TI - A bioluminescence assay using Nitrosomonas europaea for rapid and sensitive
detection of nitrification inhibitors.
AB - An expression vector for the luxAB genes, derived from Vibrio harveyi, was
introduced into Nitrosomonas europaea. Although the recombinant strain produced
bioluminescence due to the expression of the luxAB genes under normal growing
conditions, the intensity of the light emission decreased immediately, in a time
and dose-dependent manner, with the addition of ammonia monooxygenase inhibitors,
such as allylthiourea, phenol, and nitrapyrin. When whole cells were challenged
with several nitrification inhibitors and toxic compounds, a close relationship
was found between the change in the intensity of the light emission and the level
of ammonia-oxidizing activity. The response of bioluminescence to the addition of
allylthiourea was considerably faster than the change in the ammonia-oxidizing
rate, measured as both the O2 uptake and NO2- production rates. The
bioluminescence of cells inactivated by ammonia monooxygenase inhibitor was
recovered rapidly by the addition of certain substrates for hydroxylamine
oxidoreductase. These results suggested that the inhibition of bioluminescence
was caused by the immediate decrease of reducing power in the cell due to the
inactivation of ammonia monooxygenase, as well as by the destruction of other
cellular metabolic pathways. We conclude that the assay system using luminous
Nitrosomonas can be applied as a rapid and sensitive detection test for
nitrification inhibitors, and it will be used to monitor the nitrification
process in wastewater treatment plants.
PMID- 9758784
TI - Application of molecular biological techniques to a seasonal study of ammonia
oxidation in a eutrophic freshwater lake
AB - The autotrophic ammonia-oxidizing bacteria in a eutrophic freshwater lake were
studied over a 12-month period. Numbers of ammonia oxidisers in the lakewater
were small throughout the year, and tangential-flow concentration was required to
obtain meaningful estimates of most probable numbers. Sediments from littoral and
profundal sites supported comparatively large populations of these bacteria, and
the nitrification potential was high, particularly in summer samples from the
littoral sediment surface. In enrichment cultures, lakewater samples nitrified at
low (0.67 mM) ammonium concentrations only whereas sediment samples exhibited
nitrification at high (12.5 mM) ammonium concentrations also. Enrichments at low
ammonium concentration did not nitrify when inoculated into high-ammonium medium,
but the converse was not true. This suggests that the water column contains a
population of ammonia oxidizers that is sensitive to high ammonium
concentrations. The observation of nitrification at high ammonium concentration
by isolates from some winter lakewater samples, identified as nitrosospiras by
16S rRNA probing, is consistent with the hypothesis that sediment ammonia
oxidizers enter the water column at overturn. With only one exception, nested PCR
amplification enabled the detection of Nitrosospira 16S rDNA in all samples, but
Nitrosomonas (N. europaea-eutropha lineage) 16S rDNA was never obtained. However,
the latter were part of the sediment and water column communities, because their
16S rRNA could be detected by specific oligonucleotide probing of enrichment
cultures. Furthermore, a specific PCR amplification regime for the Nitrosomonas
europaea ammonia monooxygenase gene (amoA) yielded positive results when applied
directly to sediment and lakewater samples. Patterns of Nitrosospira and
Nitrosomonas detection by 16S rRNA oligonucleotide probing of sediment enrichment
cultures were complex, but lakewater enrichments at low ammonium concentration
were positive for nitrosomonads and not nitrosospiras. Analysis of enrichment
cultures has therefore provided evidence for the existence of subpopulations
within the lake ammonia-oxidizing community distinguishable on the basis of
ammonium tolerance and possibly showing a seasonal distribution between the
sediment and water column.
PMID- 9758783
TI - Characterization of an extremely thermostable restriction enzyme, PspGI, from a
Pyrococcus strain and cloning of the PspGI restriction-modification system in
Escherichia coli.
AB - An extremely thermostable restriction endonuclease, PspGI, was purified from
Pyrococcus sp. strain GI-H. PspGI is an isoschizomer of EcoRII and cleaves DNA
before the first C in the sequence 5' CCWGG 3' (W is A or T). PspGI digestion can
be carried out at 65 to 85 degrees C. To express PspGI at high levels, the PspGI
restriction-modification genes (pspGIR and pspGIM) were cloned in Escherichia
coli. M.PspGI contains the conserved sequence motifs of alpha
aminomethyltransferases; therefore, it must be an N4-cytosine methylase. M.PspGI
shows 53% similarity to (44% identity with) its isoschizomer, M.MvaI from
Micrococcus variabilis. In a segment of 87 amino acid residues, PspGI shows
significant sequence similarity to EcoRII and to regions of SsoII and StyD4I
which have a closely related recognition sequence (5' CCNGG 3'). PspGI was
expressed in E. coli via a T7 expression system. Recombinant PspGI was purified
to near homogeneity and had a half-life of 2 h at 95 degrees C. PspGI remained
active following 30 cycles of thermocycling; thus, it can be used in DNA-based
diagnostic applications.
PMID- 9758786
TI - Ellipsometric measurement of bacterial films at metal-electrolyte interfaces
AB - Ellipsometric measurements were used to monitor the formation of a bacterial cell
film on polarized metal surfaces (Al-brass and Ti). Under cathodic polarization
bacterial attachment was measured from changes in the ellipsometric angles. These
were fitted to an effective medium model for a nonabsorbing bacterial film with
an effective refractive index (nf) of 1.38 and a thickness (df) of 160 +/- 10 nm.
From the optical measurements a surface coverage of 17% was estimated, in
agreement with direct microscopic observations. The influence of bacteria on the
formation of oxide films was monitored by ellipsometry following the film growth
in situ. A strong inhibition of metal oxide film formation was observed, which
was assigned to the decrease in oxygen concentration due to the presence of
bacteria. It is shown that the irreversible adhesion of bacteria to the surface
can be monitored ellipsometrically. Electrophoretic mobility is proposed as one
of the factors determining bacterial attachment. The high sensitivity of
ellipsometry and its usefulness for the determination of growth of interfacial
bacterial films is demonstrated.
PMID- 9758785
TI - Estimation of the relative abundance of different Bacteroides and Prevotella
ribotypes in gut samples by restriction enzyme profiling of PCR-amplified 16S
rRNA gene sequences.
AB - We describe an approach for determining the genetic composition of Bacteroides
and Prevotella populations in gut contents based on selective amplification of
16S rRNA gene sequences (rDNA) followed by cleavage of the amplified material
with restriction enzymes. The relative contributions of different ribotypes to
total Bacteroides and Prevotella 16S rDNA are estimated after end labelling of
one of the PCR primers, and the contribution of Bacteroides and Prevotella
sequences to total eubacterial 16S rDNA is estimated by measuring the binding of
oligonucleotide probes to amplified DNA. Bacteroides and Prevotella 16S rDNA
accounted for between 12 and 62% of total eubacterial 16S rDNA in samples of
ruminal contents from six sheep and a cow. Ribotypes 4, 5, 6, and 7, which
include most cultivated rumen Prevotella strains, together accounted for between
20 and 86% of the total amplified Bacteroides and Prevotella rDNA in these
samples. The most abundant Bacteroides or Prevotella ribotype in four animals,
however, was ribotype 8, for which there is only one known cultured isolate,
while ribotypes 1 and 2, which include many colonic Bacteroides spp., were the
most abundant in two animals. This indicates that some abundant Bacteroides and
Prevotella groups in the rumen are underrepresented among cultured rumen
Prevotella isolates. The approach described here provides a rapid, convenient,
and widely applicable method for comparing the genotypic composition of bacterial
populations in gut samples.
PMID- 9758787
TI - Optimization of differential display of prokaryotic mRNA: application to pure
culture and soil microcosms.
AB - The differential display (DD) technique, which is widely used almost exclusively
for eukaryotic gene discovery, was optimized to detect differential mRNA
transcription from both pure-culture and soil-derived bacterial RNA. A model
system which included toluene induction of todC1 in Pseudomonas putida F1 was
used to optimize the procedure. At 24-h tod induction was determined to be
approximately 8 x 10(7) transcripts/microg or 0.08% of the total mRNA. The primer
concentration, primer length, annealing temperature, and template,
deoxynucleoside triphosphate, and MgCl2 concentrations were varied to optimize
amplification of a todC1 fragment. The limit of detection of todC1 by DD was
found to be 0.015 ng of total RNA template or approximately 10(3) transcripts.
Once optimized, a todC1C2 gene fragment from P. putida F1 RNA was detected by
using an arbitrary primer for the reverse transcriptase step in conjunction with
the same arbitrary primer and a Shine-Dalgarno primer in the PCR. To verify the
results, an arbitrary primer was used to detect recovery of a new salicylate
inducible naphthalene dioxygenase in Burkholderia cepacia JS150. The method was
then used to detect mRNA induction in both inoculated and uninoculated toluene
induced soil microcosms. Several putative differentially expressed partial gene
sequences obtained from the uninoculated microcosms were examined, and one novel
fragment was found to be differentially expressed.
PMID- 9758788
TI - Effect of butyrolactone I on the producing fungus, Aspergillus terreus.
AB - Butyrolactone I [alpha-oxo-beta-(p-hydroxyphenyl)-gamma-(p-hydroxy-m-3, 3
dimethylallyl-benzyl)-gamma-methoxycarbonyl-gamma-butyrolactone] is produced as a
secondary metabolite by Aspergillus terreus. Because small butyrolactone
containing molecules act as self-regulating factors in some bacteria, the effects
of butyrolactone I on the producing organism were studied; specifically, changes
in morphology, sporulation, and secondary metabolism were studied. Threefold or
greater increases in hyphal branching (with concomitant decreases in the average
hyphal growth unit), submerged sporulation, and secondary metabolism were
observed when butyrolactone I was added to cultures of A. terreus. Among the
secondary metabolites whose production was increased by this treatment was the
therapeutically important compound lovastatin. These findings indicate that
butyrolactone I induces morphological and sporulation changes in A. terreus and
enhances secondary metabolite production in a manner similar to that previously
reported for filamentous bacteria.
PMID- 9758789
TI - Characterization of aflJ, a gene required for conversion of pathway intermediates
to aflatoxin.
AB - The genes encoding the aflatoxin biosynthetic pathway enzymes have been localized
as a cluster to a 75-kb DNA fragment. The enzymatic functions of the products of
most of the genes in the cluster are known, but there are a few genes that have
not yet been characterized. We report here the characterization of one of these
genes, a gene designated aflJ. This gene resides in the cluster adjacent to the
pathway regulatory gene, aflR, and the two genes are divergently transcribed.
Disruption of aflJ in Aspergillus flavus results in a failure to produce
aflatoxins and a failure to convert exogenously added pathway intermediates
norsolorinic acid, sterigmatocystin, and O-methylsterigmatocystin to aflatoxin.
The disrupted strain does, however, accumulate pksA, nor-1, ver-1, and omtA
transcripts under conditions conducive to aflatoxin biosynthesis. Therefore,
disruption of aflJ does not affect transcription of these genes, and aflJ does
not appear to have a regulatory function similar to that of aflR. Sequence
analysis of aflJ and its putative peptide, AflJ, did not reveal any enzymatic
domains or significant similarities to proteins of known function. The putative
peptide does contain three regions predicted to be membrane-spanning domains and
a microbodies C-terminal targeting signal.
PMID- 9758790
TI - Regulation of aflR and its product, AflR, associated with aflatoxin biosynthesis.
AB - We studied the role of the regulatory gene aflR and its product, AflR, in the
biosynthesis of aflatoxin in Aspergillus. Western blot and enzyme-linked
immunosorbent assay analyses revealed that aflatoxin B1 accumulation was directly
related to AflR expression and was regulated by various environmental and
nutritional conditions, including temperature, air supply, carbon source,
nitrogen source, and zinc availability. Expression of an aflatoxin biosynthetic
pathway structural gene, omtA, was regulated by the presence of AflR. Induction
patterns for aflR mRNA and AflR were correlated with that for omtA mRNA in an
aflatoxin-producing strain of Aspergillus parasiticus. Analysis of non-aflatoxin
producing strains of A. flavus, A. sojae, and A. oryzae grown in medium suitable
for aflatoxin B1 production showed that both aflR mRNA and AflR production were
present; however, omtA mRNA production was not detected in any of these examined
strains. AflR in the A. oryzae strain was regulated by carbon source and
temperature in a manner similar to that seen with A. parasiticus.
PMID- 9758792
TI - Structural and functional dynamics of sulfate-reducing populations in bacterial
biofilms
AB - We describe the combined application of microsensors and molecular techniques to
investigate the development of sulfate reduction and of sulfate-reducing
bacterial populations in an aerobic bacterial biofilm. Microsensor measurements
for oxygen showed that anaerobic zones developed in the biofilm within 1 week and
that oxygen was depleted in the top 200 to 400 &mgr;m during all stages of
biofilm development. Sulfate reduction was first detected after 6 weeks of
growth, although favorable conditions for growth of sulfate-reducing bacteria
(SRB) were present from the first week. In situ hybridization with a 16S rRNA
probe for SRB revealed that sulfate reducers were present in high numbers
(approximately 10(8) SRB/ml) in all stages of development, both in the oxic and
anoxic zones of the biofilm. Denaturing gradient gel electrophoresis (DGGE)
showed that the genetic diversity of the microbial community increased during the
development of the biofilm. Hybridization analysis of the DGGE profiles with
taxon-specific oligonucleotide probes showed that Desulfobulbus and Desulfovibrio
were the main sulfate-reducing bacteria in all biofilm samples as well as in the
bulk activated sludge. However, different Desulfobulbus and Desulfovibrio species
were found in the 6th and 8th weeks of incubation, respectively, coinciding with
the development of sulfate reduction. Our data indicate that not all SRB detected
by molecular analysis were sulfidogenically active in the biofilm.
PMID- 9758791
TI - Bias in template-to-product ratios in multitemplate PCR.
AB - Bias introduced by the simultaneous amplification of specific genes from complex
mixtures of templates remains poorly understood. To explore potential causes and
the extent of bias in PCR amplification of 16S ribosomal DNAs (rDNAs), genomic
DNAs of two closely and one distantly related bacterial species were mixed and
amplified with universal, degenerate primers. Quantification and comparison of
template and product ratios showed that there was considerable and reproducible
overamplification of specific templates. Variability between replicates also
contributed to the observed bias but in a comparatively minor way. Based on these
initial observations, template dosage and differences in binding energies of
permutations of the degenerate, universal primers were tested as two likely
causes of this template-specific bias by using 16S rDNA templates modified by
site-directed mutagenesis. When mixtures of mutagenized templates containing AT-
and GC-rich priming sites were used, templates containing the GC-rich permutation
amplified with higher efficiency, indicating that different primer binding
energies may to a large extent be responsible for overamplification. In contrast,
gene copy number was found to be an unlikely cause of the observed bias.
Similarly, amplification from DNA extracted from a natural community to which
different amounts of genomic DNA of a single bacterial species were added did not
affect relative product ratios. Bias was reduced considerably by using high
template concentrations, by performing fewer cycles, and by mixing replicate
reaction preparations.
PMID- 9758793
TI - Colonization of wheat roots by an exopolysaccharide-producing pantoea agglomerans
strain and its effect on rhizosphere soil aggregation
AB - The effect of bacterial secretion of an exopolysaccharide (EPS) on rhizosphere
soil physical properties was investigated by inoculating strain NAS206, which was
isolated from the rhizosphere of wheat (Triticum durum L.) growing in a Moroccan
vertisol and was identified as Pantoea aglomerans. Phenotypic identification of
this strain with the Biotype-100 system was confirmed by amplified ribosomal DNA
restriction analysis. After inoculation of wheat seedlings with strain NAS206,
colonization increased at the rhizoplane and in root-adhering soil (RAS) but not
in bulk soil. Colonization further increased under relatively dry conditions (20%
soil water content; matric potential, -0.55 MPa). By means of genetic
fingerprinting using enterobacterial repetitive intergenic consensus PCR, we were
able to verify that colonies counted as strain NAS206 on agar plates descended
from inoculated strain NAS206. The intense colonization of the wheat rhizosphere
by these EPS-producing bacteria was associated with significant soil aggregation,
as shown by increased ratios of RAS dry mass to root tissue (RT) dry mass
(RAS/RT) and the improved water stability of adhering soil aggregates. The
maximum effect of strain NAS206 on both the RAS/RT ratio and aggregate stability
was measured at 24% average soil water content (matric potential, -0.20 MPa).
Inoculated strain NAS206 improved RAS macroporosity (pore diameter, 10 to 30
&mgr;m) compared to the noninoculated control, particularly when the soil was
nearly water saturated (matric potential, -0.05 MPa). Our results suggest that P.
agglomerans NAS206 can play an important role in the regulation of the water
content (excess or deficit) of the rhizosphere of wheat by improving soil
aggregation.
PMID- 9758796
TI - Toxic effects of modified fenton reactions on xanthobacter flavus FB71
AB - The toxic effects of modified Fenton reactions on Xanthobacter flavus FB71,
measured as microbial survival rates, were determined as part of an investigation
of simultaneous abiotic and biotic oxidations of xenobiotic chemicals. A central
composite, rotatable experimental design was developed to study the survival
rates of X. flavus under various concentrations of hydrogen peroxide and iron(II)
and at different initial cell populations. A model based on the experimental
results, relating microorganism survival to the variables of peroxide, iron, and
cellular concentrations was formulated and fit the data reasonably well, with a
coefficient of determination of 0.76. The results of this study indicate that the
use of simultaneous abiotic and biotic processes for the treatment of xenobiotic
compounds may be possible.
PMID- 9758795
TI - Enhanced utilization of phosphonate and phosphite by Klebsiella aerogenes.
AB - Klebsiella aerogenes ATCC 9621 was able to utilize phosphonates (Pn), including
aminoethylphosphonate, ethylphosphonate, methylphosphonate (MPn), and
phosphonoacetate, and inorganic phosphite (Pt) as sole sources of phosphorus (P).
The products of the phn gene cluster were absolutely required for Pn breakdown
and Pt oxidation to inorganic phosphate (Pi) in this organism. To determine if K.
aerogenes ATCC 9621 could be engineered to enhance the utilization of Pn and Pt,
a multicopy plasmid, pBI05, which carried the entire phn gene cluster, was
introduced into this strain. Despite the increased dosage of the phn genes, K.
aerogenes ATCC 9621(pBI05) could utilize only up to 1.1-fold more Pn and Pt than
did the control strain with the parent vector alone. These results suggested that
Pi, which was generated from Pn and Pt, might limit further utilization of these
P compounds. Consequently, to convert the resulting Pi to polyphosphate (polyP),
the plasmid pKP28, which carried the K. aerogenes ppk gene (which encodes polyP
kinase), was introduced into K. aerogenes ATCC 9621(pBI05). Overexpression of the
ppk gene in K. aerogenes ATCC 9621(pBI05, pKP28) resulted in a 2.5-fold increase
in Pt utilization over that of the control strain. This recombinant strain also
accumulated approximately sixfold more P than did the control strain when the
cells were grown with MPn as a sole source of P.
PMID- 9758794
TI - Capacity of nine thermostable DNA polymerases To mediate DNA amplification in the
presence of PCR-inhibiting samples.
AB - The PCR is an extremely powerful method for detecting microorganisms. However,
its full potential as a rapid detection method is limited by the inhibition of
the thermostable DNA polymerase from Thermus aquaticus by many components found
in complex biological samples. In this study, we have compared the effects of
known PCR-inhibiting samples on nine thermostable DNA polymerases. Samples of
blood, cheese, feces, and meat, as well as various ions, were added to PCR
mixtures containing various thermostable DNA polymerases. The nucleic acid
amplification capacity of the nine polymerases, under buffer conditions
recommended by the manufacturers, was evaluated by using a PCR-based detection
method for Listeria monocytogenes in the presence of purified template DNA and
different concentrations of PCR inhibitors. The AmpliTaq Gold and the Taq DNA
polymerases from Thermus aquaticus were totally inhibited in the presence of
0.004% (vol/vol) blood in the PCR mixture, while the HotTub, Pwo, rTth, and Tfl
DNA polymerases were able to amplify DNA in the presence of 20% (vol/vol) blood
without reduced amplification sensitivity. The DNA polymerase from Thermotoga
maritima (Ultma) was found to be the most susceptible to PCR inhibitors present
in cheese, feces, and meat samples. When the inhibitory effect of K and Na ions
was tested on the nine polymerases, HotTub from Thermus flavus and rTth from
Thermus thermophilus were the most resistant. Thus, the PCR-inhibiting effect of
various components in biological samples can, to some extent, be eliminated by
the use of the appropriate thermostable DNA polymerase.
PMID- 9758797
TI - Xanthan lyase of Bacillus sp. strain GL1 liberates pyruvylated mannose from
xanthan side chains.
AB - When the bacterium Bacillus sp. strain GL1 was grown in a medium containing
xanthan as the carbon source, the viscosity of the medium decreased in
association with growth, showing that the bacterium had xanthan-depolymerizing
enzymes. One of the xanthan-depolymerizing enzymes (xanthan lyase) was present in
the medium and was found to be induced by xanthan. The xanthan lyase purified
from the culture fluid was a monomer with a molecular mass of 75 kDa, and was
most active at pH 5.5 and 50 degrees C. The enzyme was highly specific for
xanthan and produced pyruvylated mannose. The result indicates that the enzyme
cleaved the linkage between the terminal pyruvylated mannosyl and glucuronyl
residues in the side chain of xanthan.
PMID- 9758798
TI - Development of PCR primer systems for amplification of nitrite reductase genes
(nirK and nirS) to detect denitrifying bacteria in environmental samples.
AB - A system was developed for the detection of denitrifying bacteria by the
amplification of specific nitrite reductase gene fragments with PCR. Primer
sequences were found for the amplification of fragments from both nitrite
reductase genes (nirK and nirS) after comparative sequence analysis. Whenever
amplification was tried with these primers, the known nir type of denitrifying
laboratory cultures could be confirmed. Likewise, the method allowed a
determination of the nir type of five laboratory strains. The nirK gene could be
amplified from Blastobacter denitrificans, Alcaligenes xylosoxidans, and
Alcaligenes sp. (DSM 30128); the nirS gene was amplified from Alcaligenes
eutrophus DSM 530 and from the denitrifying isolate IFAM 3698. For each of the
two genes, at least one primer combination amplified successfully for all of the
test strains. Specific amplification products were not obtained with
nondenitrifying bacteria or with strains of the other nir type. The specificity
of the amplified products was confirmed by subsequent sequencing. These results
suggest the suitability of the method for the qualitative detection of
denitrifying bacteria in environmental samples. This was shown by applying one
generally amplifying primer combination for each nir gene developed in this study
to total DNA preparations from aquatic habitats.
PMID- 9758799
TI - Distribution and life strategies of two bacterial populations in a eutrophic lake
AB - Monoclonal antibodies and epifluorescence microscopy were used to determine the
depth distribution of two indigenous bacterial populations in the stratified Lake
Plusssee and characterize their life strategies. Populations of Comamonas
acidovorans PX54 showed a depth distribution with maximum abundances in the oxic
epilimnion, whereas Aeromonas hydrophila PU7718 showed a depth distribution with
maximum abundances in the anoxic thermocline layer (metalimnion), i. e., in the
water layer with the highest microbial activity. Resistance of PX54 to protist
grazing and high metabolic versatility and growth rate of PU7718 were the most
important life strategy traits for explaining the depth distribution of the two
bacterial populations. Maximum abundance of PX54 was 16,000 cells per ml, and
maximum abundance of PU7718 was 20,000 cells per ml. Determination of bacterial
productivity in dilution cultures with different-size fractions of dissolved
organic matter (DOM) from lake water indicates that low-molecular-weight (LMW)
DOM is less bioreactive than total DOM (TDOM). The abundance and growth rate of
PU7718 were highest in the TDOM fractions, whereas those of PX54 were highest in
the LMW DOM fraction, demonstrating that PX54 can grow well on the less
bioreactive DOM fraction. We estimated that 13 to 24% of the entire bacterial
community and 14% of PU7718 were removed by viral lysis, whereas no significant
effect of viral lysis on PX54 could be detected. Growth rates of PX54 (0.11 to
0.13 h-1) were higher than those of the entire bacterial community (0.04 to 0.08
h-1) but lower than those of PU7718 (0.26 to 0.31 h-1). In undiluted cultures,
the growth rates were significantly lower, pointing to density effects such as
resource limitation or antibiosis, and the effects were stronger for PU7718 and
the entire bacterial community than for PX54. Life strategy characterizations
based on data from literature and this study revealed that the fast-growing and
metabolically versatile A. hydrophila PU7718 is an r-strategist or opportunistic
population in Lake Plusssee, whereas the grazing-resistant C. acidovorans PX54 is
rather a K-strategist or equilibrium population.
PMID- 9758801
TI - Manganese reduction by microbes from oxic regions of the lake vanda (Antarctica)
water column
AB - Depth profiles of metals in Lake Vanda, a permanently ice-covered, stratified
Antarctic lake, suggest the importance of particulate manganese oxides in the
scavenging, transport, and release of metals. Since manganese oxides can be
solubilized by manganese-reducing bacteria, microbially mediated manganese
reduction was investigated in Lake Vanda. Microbes concentrated from oxic regions
of the water column, encompassing a peak of soluble manganese [Mn(II)], reduced
synthetic manganese oxides (MnO2) when incubated aerobically. Pure cultures of
manganese-reducing bacteria were readily isolated from waters collected near the
oxic Mn(II) peak. Based on phylogenetic analysis of the 16S rRNA gene sequence,
most of the isolated manganese reducers belong to the genus Carnobacterium.
Cultures of a phylogenetically representative strain of Carnobacterium reduced
synthetic MnO2 in the presence of sodium azide, as was seen in field assays.
Unlike anaerobes that utilize manganese oxides as terminal electron acceptors in
respiration, isolates of the genus Carnobacterium reduced Mn(IV) via a diffusible
compound under oxic conditions. The release of adsorbed trace metals accompanying
the solubilization of manganese oxides may provide populations of Carnobacterium
with a source of nutrients in this extremely oligotrophic environment.
PMID- 9758800
TI - Biocatalyst engineering by assembly of fatty acid transport and oxidation
activities for In vivo application of cytochrome P-450BM-3 monooxygenase.
AB - The application of whole cells containing cytochrome P-450BM-3 monooxygenase [EC
1.14.14.1] for the bioconversion of long-chain saturated fatty acids to omega-1,
omega-2, and omega-3 hydroxy fatty acids was investigated. We utilized
pentadecanoic acid and studied its conversion to a mixture of 12-, 13-, and 14
hydroxypentadecanoic acids by this monooxygenase. For this purpose, Escherichia
coli recombinants containing plasmid pCYP102 producing the fatty acid
monooxygenase cytochrome P-450BM-3 were used. To overcome inefficient uptake of
pentadecanoic acid by intact E. coli cells, we made use of a cloned fatty acid
uptake system from Pseudomonas oleovorans which, in contrast to the common FadL
fatty acid uptake system of E. coli, does not require coupling by FadD (acyl
coenzyme A synthetase) of the imported fatty acid to coenzyme A. This system from
P. oleovorans is encoded by a gene carried by plasmid pGEc47, which has been
shown to effect facilitated uptake of oleic acid in E. coli W3110 (M. Nieboer,
Ph.D. thesis, University of Groningen, Groningen, The Netherlands, 1996). By
using a double recombinant of E. coli K27, which is a fadD mutant and therefore
unable to consume substrates or products via the beta-oxidation cycle, a twofold
increase in productivity was achieved. Applying cytochrome P-450BM-3
monooxygenase as a biocatalyst in whole cells does not require the exogenous
addition of the costly cofactor NADPH. In combination with the coenzyme A
independent fatty acid uptake system from P. oleovorans, cytochrome P-450BM-3
recombinants appear to be useful alternatives to the enzymatic approach for the
bioconversion of long-chain fatty acids to subterminal hydroxylated fatty acids.
PMID- 9758802
TI - Degradation of 1,2,3,4-tetrachlorobenzene by pseudomonas chlororaphis RW71
AB - Pseudomonas chlororaphis RW71 mineralized 1,2,3,4-tetrachlorobenzene, a highly
recalcitrant pollutant hitherto not known to be degraded by pure cultures, as a
sole source of carbon and energy, thereby releasing stoichiometric amounts of
chloride. The transient excretion of tetrachlorocatechol in the early growth
phase suggests an initial attack by a dioxygenase to form the corresponding
dihydrodiol which rearomatizes to the catechol. The activity of chlorocatechol
1,2-dioxygenase in crude cell extracts was found to be extraordinarily high
towards 3-chlorocatechol (ratio of 2.6 compared to catechol) and other
chlorocatechols, including tetrachlorocatechol, which was transformed at a low
but significant rate. Further identification of tetrachloromuconic acid, 2,3, 5
trichlorodienelactone, 2,3,5-trichloromaleyl acetic acid, and 2, 4-dichloro-3
oxoadipic acid as their methyl esters, together with high specific enzyme
activities for chlorinated substrates, implicated a functioning chlorocatechol
pathway to be induced during growth.
PMID- 9758804
TI - Quantitative and physiological analyses of chloride dependence of growth of
halobacillus halophilus
AB - A quantitative analysis of the Cl- dependence of growth of Halobacillus
halophilus was performed. Optimal growth rates were obtained at Cl-
concentrations of between 0.5 and 2.0 M, and the final yield was also strictly
dependent on the Cl- concentration. Br- but not I-, SO42-, NO2-, SO2-, OCN-, SCN
, BO2-, or BrO3- could substitute for Cl-. To analyze the function of chloride,
chloride concentration was determined. At low external Cl- (Cle-) concentrations,
the growth rate was low and Cl- was excluded from the cytoplasm; increasing the
Cle- concentration led to an increase in the growth rate and an energy-dependent
uptake of Cl-, thus decreasing the Cle-/internal Cli- gradient from >/=10 at 0.1
M Cle- to a nearly constant value of 2 at Cle- concentrations which allowed
optimal growth. Two membrane proteins with apparent molecular masses of 31 and 16
kDa which were identified to be specific for Cl--grown cultures are possible
candidates for a chloride uptake system.
PMID- 9758803
TI - Characteristics of airborne actinomycete spores.
AB - Airborne actinomycete spores, important contaminants in occupational and
residential environments, were studied with respect to their (i) release into the
air, (ii) aerodynamic and physical size while airborne, and (iii) survival after
collection onto agar with an impactor. Three actinomycete species were selected
for the tests to exemplify the three main spore types: Streptomyces albus for
arthrospores, Micromonospora halophytica for aleuriospores, and Thermoactinomyces
vulgaris for endospores. The results show that the incubation conditions
(temperature, time, and nutrients) needed for the development of spores for their
release into air are different from the conditions that are needed for colony
growth only. Additional drying of M. halophytica and T. vulgaris cultures was
needed before spores could be released from the culture. The aerodynamic sizes of
the spores, measured with an aerodynamic particle sizer, ranged from 0.57 (T.
vulgaris) to 1.28 micron (M. halophytica). The physical sizes of the spores, when
measured with a microscope and an image analysis system, were found to be smaller
than previously reported in the literature. The relative recovery of the spores
on agar media ranged from 0.5 (T. vulgaris) to 35% (S. albus). The results
indicate that the culturability of the collected airborne actinomycete spores
varies widely and is affected by several variables, such as the species and the
sampling flow rate. Therefore, alternatives to commonly used cultivation methods
need to be developed for the enumeration of actinomycete spores.
PMID- 9758805
TI - Genetic characterization of pseudomonas syringae pv. syringae strains from stone
fruits in california
AB - Strains of Pseudomonas syringae pv. syringae were isolated from healthy and
diseased stone fruit tissues sampled from 43 orchard sites in California in 1995
and 1996. These strains, together with P. syringae strains from other hosts and
pathovars, were tested for pathogenicity and the presence of the syrB and syrC
genes and were genetically characterized by using enterobacterial repetitive
intergenic consensus (ERIC) primers and PCR. All 89 strains of P. syringae pv.
syringae tested were moderately to highly pathogenic on Lovell peach seedlings
regardless of the host of origin, while strains of other pathovars exhibited low
or no pathogenicity. The 19 strains of P. syringae pv. syringae examined by
restriction fragment length polymorphism analysis contained the syrB and syrC
genes, whereas no hybridization occurred with 4 strains of other P. syringae
pathovars. The P. syringae pv. syringae strains from stone fruit, except for a
strain from New Zealand, generated ERIC genomic fingerprints which shared four
fragments of similar mobility. Of the P. syringae pv. syringae strains tested
from other hosts, only strains from rose, kiwi, and pear generated genomic
fingerprints that had the same four fragments as the stone fruit strains.
Analysis of the ERIC fingerprints from P. syringae pv. syringae strains showed
that the strains isolated from stone fruits formed a distinct cluster separate
from most of the strains isolated from other hosts. These results provide
evidence of host specialization within the diverse pathovar P. syringae pv.
syringae.
PMID- 9758806
TI - Phenotypic and phylogenetic characterization of ruminal tannin-tolerant bacteria.
AB - The 16S rRNA sequences and selected phenotypic characteristics were determined
for six recently isolated bacteria that can tolerate high levels of hydrolyzable
and condensed tannins. Bacteria were isolated from the ruminal contents of
animals in different geographic locations, including Sardinian sheep (Ovis
aries), Honduran and Colombian goats (Capra hircus), white-tail deer (Odocoileus
virginianus) from upstate New York, and Rocky Mountain elk (Cervus elaphus
nelsoni) from Oregon. Nearly complete sequences of the small-subunit rRNA genes,
which were obtained by PCR amplification, cloning, and sequencing, were used for
phylogenetic characterization. Comparisons of the 16S rRNA of the six isolates
showed that four of the isolates were members of the genus Streptococcus and were
most closely related to ruminal strains of Streptococcus bovis and the recently
described organism Streptococcus gallolyticus. One of the other isolates, a gram
positive rod, clustered with the clostridia in the low-G+C-content group of gram
positive bacteria. The sixth isolate, a gram-negative rod, was a member of the
family Enterobacteriaceae in the gamma subdivision of the class Proteobacteria.
None of the 16S rRNA sequences of the tannin-tolerant bacteria examined was
identical to the sequence of any previously described microorganism or to the
sequence of any of the other organisms examined in this study. Three
phylogenetically distinct groups of ruminal bacteria were isolated from four
species of ruminants in Europe, North America, and South America. The presence of
tannin-tolerant bacteria is not restricted by climate, geography, or host animal,
although attempts to isolate tannin-tolerant bacteria from cows on low-tannin
diets failed.
PMID- 9758808
TI - Enzymatic activity, bacterial distribution, and organic matter composition in
sediments of the ross sea (Antarctica)
AB - Enzymatic activities of aminopeptidase and beta-glucosidase were investigated in
Antarctic Ross Sea sediments at two sites (sites B and C, 567 and 439 m deep,
respectively). The sites differed in trophic conditions related to organic matter
(OM) composition and bacterial distribution. Carbohydrate concentrations at site
B were about double those at site C, while protein and lipid levels were 10 times
higher. Proteins were mainly found in a soluble fraction (>90%). Chloropigment
content was generally low and phaeopigments were almost absent, indicating the
presence of reduced inputs of primary organic matter. ATP concentrations (as a
measure of the living microbial biomass) were significantly higher at site B. By
contrast, benthic bacterial densities at site C were about double those at site
B. Bacterial parameters do not appear to be "bottom-up controlled" by the amount
of available food but rather "top-down controlled" by meiofauna predatory
pressure, which was significantly higher at site B. Aminopeptidase and beta
glucosidase extracellular enzyme activities (EEA) in Antarctic sediments appear
to be high and comparable to those reported for temperate or Arctic sediments and
characterized by low aminopeptidase/beta-glucosidase ratios (about 10). Activity
profiles showed decreasing patterns with increasing sediment depth, indicating
vertical shifts in both availability and nutritional quality of degradable OM.
Vertical profiles of aminopeptidase activity were related to a decrease in
protein concentration and/or to an increase in the insoluble refractory
proteinaceous fraction. The highest aminopeptidase activity rates were observed
at site C, characterized by much lower protein concentrations. Differences in EEA
between sites do not seem to be explained by differences in the in situ
temperature (-1.6 and -0.8 degreesC at sites B and C, respectively).
Aminopeptidase activity profiles are consistent with the bacterial biomass and
frequency of dividing cells. Enzyme substrate affinity was generally dependent
upon substrate concentrations. EEA, normalized to bacterial numbers, indicated
specific activities comparable to those reported for equally deep sediments at
temperate latitudes. Vertical patterns of specific enzymatic activity appeared to
be controlled by chloroplastic pigment concentrations that accumulate in the
deeper sediment layers. The overall conclusion from the analysis of EEA in
Antarctic sediments is that enzyme-dependent transformations of OM proceed at
rates similar to those measured in temperate environments. Protein carbon
potentially liberated by aminopeptidase activities (12.597 to 26.190 mg of C m-2
day-1) indicates that the whole protein pool could be mobilized within 1.3 to 17
h. Carbohydrate carbon mobilization (773 to 2,552 mg of C m-2 day-1) is
sufficient to turn over the carbohydrate pool within 16 to 20 h. Such rates are 6
to 45 times higher than fluxes of particulate organic proteins and carbohydrates,
indicating an "uncoupled hydrolysis" by the Antarctic benthic assemblages, in
which bacteria appear to be able to rapidly exploit episodic OM pulses.
PMID- 9758807
TI - Improvement of nitrogen assimilation and fermentation kinetics under enological
conditions by derepression of alternative nitrogen-assimilatory pathways in an
industrial Saccharomyces cerevisiae strain.
AB - Metabolism of nitrogen compounds by yeasts affects the efficiency of wine
fermentation. Ammonium ions, normally present in grape musts, reduce catabolic
enzyme levels and transport activities for nonpreferred nitrogen sources. This
nitrogen catabolite repression severely impairs the utilization of proline and
arginine, both common nitrogen sources in grape juice that require the proline
utilization pathway for their assimilation. We attempted to improve fermentation
performance by genetic alteration of the regulation of nitrogen-assimilatory
pathways in Saccharomyces cerevisiae. One mutant carrying a recessive allele of
ure2 was isolated from an industrial S. cerevisiae strain. This mutation strongly
deregulated the proline utilization pathway. Fermentation kinetics of this mutant
were studied under enological conditions on simulated standard grape juices with
various nitrogen levels. Mutant strains produced more biomass and exhibited a
higher maximum CO2 production rate than the wild type. These differences were
primarily due to the derepression of amino acid utilization pathways. When low
amounts of dissolved oxygen were added, the mutants could assimilate proline.
Biomass yield and fermentation rate were consequently increased, and the duration
of the fermentation was substantially shortened. S. cerevisiae strains lacking
URE2 function could improve alcoholic fermentation of natural media where proline
and other poorly assimilated amino acids are the major potential nitrogen source,
as is the case for most fruit juices and grape musts.
PMID- 9758809
TI - Interlaboratory comparison of methods To quantify microsclerotia of verticillium
dahliae in soil
AB - In a comparison of different methods for estimating Verticillium dahliae in soil,
14 soil samples were analyzed in a blinded fashion by 13 research groups in seven
countries, using their preferred methods. One group analyzed only four samples.
Twelve soil samples were naturally infested, and two had known numbers of
microsclerotia of V. dahliae added to them. In addition, a control was included
to determine whether transport had an effect on the results. Results differed
considerably among the research groups. There was a 118-fold difference between
the groups with the lowest and highest mean estimates. Results of the other
groups were evenly distributed between these extremes. In general, methods based
on plating dry soil samples gave higher numbers of V. dahliae than did plating of
an aqueous soil suspension. Recovery of V. dahliae from samples with added
microsclerotia varied from 0 to 59%. Most of the variability within each analysis
was at the petri dish level. The results indicate the necessity to check the
performance of detection assays regularly by comparing recoveries with other
laboratories, using a common set of soil samples. We conclude that wet plating
assays are less accurate than dry plating assays.
PMID- 9758810
TI - Temperature gradient gel electrophoresis analysis of 16S rRNA from human fecal
samples reveals stable and host-specific communities of active bacteria.
AB - The diversity of the predominant bacteria in the human gastrointestinal tract was
studied by using 16S rRNA-based approaches. PCR amplicons of the V6 to V8 regions
of fecal 16S rRNA and ribosomal DNA (rDNA) were analyzed by temperature gradient
gel electrophoresis (TGGE). TGGE of fecal 16S rDNA amplicons from 16 individuals
showed different profiles, with some bands in common. Fecal samples from two
individuals were monitored over time and showed remarkably stable profiles over a
period of at least 6 months. TGGE profiles derived from 16S rRNA and rDNA
amplicons showed similar banding patterns. However, the intensities of bands with
similar mobilities differed in some cases, indicating a different contribution to
the total active fraction of the prominent fecal bacteria. Most 16S rRNA
amplicons in the TGGE pattern of one subject were identified by cloning and
sequence analysis. Forty-five of the 78 clones matched 15 bands, and 33 clones
did not match any visible band in the TGGE pattern. Nested PCR of amplified 16S
rDNA indicated preferential amplification of a sequence corresponding to 12 of
the 33 nonmatching clones with similar mobilities in TGGE. The sequences matching
15 bands in the TGGE pattern showed 91.5 to 98.7% homology to sequences derived
from different Clostridium clusters. Most of these were related to strains
derived from the human intestine. The results indicate that the combination of
cloning and TGGE analysis of 16S rDNA amplicons is a reliable approach to
monitoring different microbial communities in feces.
PMID- 9758811
TI - Comparison of paenibacillus azotofixans strains isolated from rhizoplane,
rhizosphere, and non-root-associated soil from maize planted in two different
brazilian soils
AB - Paenibacillus azotofixans is a nitrogen-fixing bacterium often found in soil and
in the rhizospheres of different grasses. In this study, two Brazilian clay soils
were planted with cross-hybrid maize (BR-201) and four stages of plant growth
were analyzed to characterize the P. azotofixans populations present in the
rhizoplanes, rhizospheres, and non-root-associated soils (herein called
nonrhizospheres). A total of 106 strains were isolated and identified as P.
azotofixans with an API 50CH kit, by classical biochemical tests, and via the use
of specific primers based on the 16S rRNA gene in PCRs. To compare the isolated
strains, phenotypic characteristics were determined and three different probes
were used in hybridization experiments: two nif probes and one probe comprising a
0.58-kb fragment cloned from the P. azotofixans C3L4 genome. These results were
used to construct a dendrogram, in which two main clusters could be observed. One
cluster contained exclusively strains from Varzea soil, and the other contained
the majority of strains from Cerrado soil. The 60 strains from Varzea soil and
the 46 strains from Cerrado soil were further analyzed with REP and BOX primers,
respectively. Based on the patterns obtained, it was possible to identify 21
different groups among strains from Varzea soil and 4 different groups among
strains from Cerrado soil. These different patterns were tested by multivariate
analysis of variance, and differences in the populations of P. azotofixans during
the four stages of plant growth were demonstrated. Moreover, strains isolated
from the rhizoplanes, rhizospheres, and nonrhizospheres of maize planted in
Cerrado and Varzea soils were shown to be statistically different; the diversity
of P. azotofixans strains was affected by the soil type.
PMID- 9758812
TI - Microbial diversity in a hydrocarbon- and chlorinated-solvent-contaminated
aquifer undergoing intrinsic bioremediation.
AB - A culture-independent molecular phylogenetic approach was used to survey
constituents of microbial communities associated with an aquifer contaminated
with hydrocarbons (mainly jet fuel) and chlorinated solvents undergoing intrinsic
bioremediation. Samples were obtained from three redox zones: methanogenic,
methanogenic-sulfate reducing, and iron or sulfate reducing. Small-subunit rRNA
genes were amplified directly from aquifer material DNA by PCR with universally
conserved or Bacteria- or Archaea-specific primers and were cloned. A total of
812 clones were screened by restriction fragment length polymorphisms (RFLP),
approximately 50% of which were unique. All RFLP types that occurred more than
once in the libraries, as well as many of the unique types, were sequenced. A
total of 104 (94 bacterial and 10 archaeal) sequence types were determined. Of
the 94 bacterial sequence types, 10 have no phylogenetic association with known
taxonomic divisions and are phylogenetically grouped in six novel division level
groups (candidate divisions WS1 to WS6); 21 belong to four recently described
candidate divisions with no cultivated representatives (OP5, OP8, OP10, and
OP11); and 63 are phylogenetically associated with 10 well-recognized divisions.
The physiology of two particularly abundant sequence types obtained from the
methanogenic zone could be inferred from their phylogenetic association with
groups of microorganisms with a consistent phenotype. One of these sequence types
is associated with the genus Syntrophus; Syntrophus spp. produce energy from the
anaerobic oxidation of organic acids, with the production of acetate and
hydrogen. The organism represented by the other sequence type is closely related
to Methanosaeta spp., which are known to be capable of energy generation only
through aceticlastic methanogenesis. We hypothesize, therefore, that the terminal
step of hydrocarbon degradation in the methanogenic zone of the aquifer is
aceticlastic methanogenesis and that the microorganisms represented by these two
sequence types occur in syntrophic association.
PMID- 9758813
TI - Stereo- and regioselective hydroxylation of alpha-ionone by Streptomyces strains.
AB - A total of 215 Streptomyces strains were screened for their capacity to regio-
and stereoselectively hydroxylate beta- and/or alpha-ionone to the respective 3
hydroxy derivatives. With beta-ionone as the substrate, 15 strains showed little
conversion to 4-hydroxy- and none showed conversion to the 3-hydroxy product as
desired. Among these 15 Streptomyces strains, S. fradiae Tu 27, S. arenae Tu 495,
S. griseus ATCC 13273, S. violaceoniger Tu 38, and S. antibioticus Tu 4 and Tu 46
converted alpha-ionone to 3-hydroxy-alpha-ionone with significantly higher
hydroxylation activity compared to that of beta-ionone. Hydroxylation of racemic
alpha-ionone [(6R)-(-)/(6S)-(+)] resulted in the exclusive formation of only the
two enantiomers (3R,6R)- and (3S, 6S)-hydroxy-alpha-ionone. Thus, the enzymatic
hydroxylation of alpha-ionone by the Streptomyces strains tested proceeds with
both high regio- and stereoselectivity.
PMID- 9758814
TI - Acid-sensitive enteric pathogens are protected from killing under extremely
acidic conditions of pH 2.5 when they are inoculated onto certain solid food
sources.
AB - Gastric acidity is recognized as the first line of defense against food-borne
pathogens, and the ability of pathogens to resist this pH corresponds to their
oral infective dose (ID). Naturally occurring and genetically engineered acid
sensitive enteric pathogens were examined for their ability to survive under
acidic conditions of pH 2.5 for 2 h at 37 degreesC when inoculated onto ground
beef. Each of the strains displayed significantly high survival rates under these
normally lethal conditions. The acid-sensitive pathogens Campylobacter jejuni and
Vibrio cholerae, which were protected at lower levels from acid-induced killing
by ground beef under these conditions, were sensitive to killing in acidified
media at pH 5.0 but survived at pH 6.0. Salmonella inoculated onto the surface of
preacidified ground beef could not survive if the pH on the surface of the beef
was 2.61 or lower but was viable if the surface pH was 3. 27. This implies that
the pH of the microenvironment occupied by the bacteria on the surface of the
food source is critical for their survival. Salmonella was also shown to be
protected from killing when inoculated onto boiled egg white, a food source high
in protein and low in fat. These results may explain why Salmonella species have
a higher oral ID of approximately 10(5) cells when administered under defined
conditions but have been observed to cause disease at doses as low as 50 to 100
organisms when consumed as part of a contaminated food source. They may also help
explain why some pathogens are associated primarily with food-borne modes of
transmission rather than fecal-oral transmission.
PMID- 9758815
TI - New hybrids between Saccharomyces sensu stricto yeast species found among wine
and cider production strains.
AB - Two yeast isolates, a wine-making yeast first identified as a Mel+ strain (ex. S.
uvarum) and a cider-making yeast, were characterized for their nuclear and
mitochondrial genomes. Electrophoretic karyotyping analyses, restriction fragment
length polymorphism maps of PCR-amplified MET2 gene fragments, and the sequence
analysis of a part of the two MET2 gene alleles found support the notion that
these two strains constitute hybrids between Saccharomyces cerevisiae and
Saccharomyces bayanus. The two hybrid strains had completely different
restriction patterns of mitochondrial DNA as well as different sequences of the
OLI1 gene. The sequence of the OLI1 gene from the wine hybrid strain appeared to
be the same as that of the S. cerevisiae gene, whereas the OLI1 gene of the cider
hybrid strain is equally divergent from both putative parents, S. bayanus and S.
cerevisiae. Some fermentative properties were also examined, and one phenotype
was found to reflect the hybrid nature of these two strains. The origin and
nature of such hybridization events are discussed.
PMID- 9758816
TI - Effects of visible light and UV radiation on photosynthesis in a population of a
hot spring cyanobacterium, a synechococcus sp., subjected to high-temperature
stress
AB - Assays of photosynthesis were conducted with a biofilm population of a
cyanobacterium, a Synechococcus sp., growing at approximately 70 degreesC in a
Yellowstone National Park hot spring to test whether cells growing near the upper
temperature limit of photosynthetic life are optimally adapted to their mean
environmental temperature. Cell suspensions were assayed at 70, 65, and 55
degreesC while being simultaneously exposed to modified solar environments,
including reduction of total irradiance and exclusion of UV radiation. Carbon
fixation was greatest at 65 degreesC, while 70 and 55 degreesC were always
supraoptimal and suboptimal for photosynthesis, respectively. The degree of
temperature stress was dependent upon light intensity, and this light-dependent
temperature effect may involve both reduced quantum efficiency at subsaturating
irradiances and a lower saturating irradiance at both supraoptimal and suboptimal
temperatures. The Synechococcus sp. was also more susceptible to UV inhibition of
photosynthesis at nonoptimal temperatures. These results suggest that this
population is persisting at a nearly lethal temperature and is consequently
subject to greater damage by both visible and UV radiation, but it is speculated
that these cells may be avoiding competition with other photoautotrophs under
these nonoptimal conditions. In separate experiments monitoring diurnal patterns
of photosynthesis, cells exhibited peak productivity during the morning, followed
by an afternoon decline. No recovery of photosynthesis was observed during the
remaining daytime, and carbon fixation was always UV inhibited under conditions
of photosynthetically saturating light.
PMID- 9758817
TI - Determination of the biomasses of small bacteria at low concentrations in a
mixture of species with forward light scatter measurements by flow cytometry
AB - The forward light scatter intensity of bacteria analyzed by flow cytometry varied
with their dry mass, in accordance with theory. A standard curve was formulated
with Rayleigh-Gans theory to accommodate cell shape and alignment. It was
calibrated with an extinction-culture isolate of the small marine organism
Cycloclasticus oligotrophus, for which dry weight was determined by CHN analysis
and 14C-acetate incorporation. Increased light scatter intensity due to
formaldehyde accumulation in preserved cells was included in the standard curve.
When differences in the refractive indices of culture media and interspecies
differences in the effects of preservation were taken into account, there was
agreement between cell mass obtained by flow cytometry for various bacterial
species and cell mass computed from Coulter Counter volume and buoyant density.
This agreement validated the standard curve and supported the assumption that
cells were aligned in the flow stream. Several subpopulations were resolved in a
mixture of three species analyzed according to forward light scatter and DNA
bound DAPI (4', 6-diamidino-2-phenylindole) fluorescence intensity. The total
biomass of the mixture was 340 &mgr;g/liter. The lowest value for mean dry mass,
0.027 +/- 0.008 pg/cell, was for the subpopulation of C. oligotrophus containing
cells with a single chromosome. Calculations from measurements of dry mass,
Coulter Counter volume, and buoyant density revealed that the dry weight of the
isolate was 14 to 18% of its wet weight, compared to 30% for Escherichia coli.
The method is suitable for cells with 0.005 to about 1.2 pg of dry weight at
concentrations of as low as 10(3) cells/ml and offers a unique capability for
determining biomass distributions in mixed bacterial populations.
PMID- 9758818
TI - The introduction into bacillus sphaericus of the Bacillus thuringiensis subsp.
medellin Cyt1Ab1 gene results in higher susceptibility of resistant mosquito
larva populations to B. sphaericus.
AB - The fragment containing the gene encoding the cytolytic Cyt1Ab1 protein from
Bacillus thuringiensis subsp. medellin and its flanking sequences (I. Thiery, A.
Delecluse, M. C. Tamayo, and S. Orduz, Appl. Environ. Microbiol. 63:468-473,
1997) was introduced into Bacillus sphaericus toxic strains 2362, 2297, and
Iab872 by electroporation with the shuttle vector pMK3. Only small amounts of the
protein were produced in recombinant strains 2362 and Iab872. The protein was
detected in these strains only by Western blotting and immunodetection with
antibody raised against Cyt1Ab1 protein. Large amounts of Cyt1Ab1 protein were
produced in B. sphaericus recombinant strain 2297, and there was an additional
crystal, other than that of the binary toxin, within the exosporium. The
production of the Cyt1Ab1 protein in addition to the binary toxin did not
increase the larvicidal activity of the B. sphaericus recombinant strain against
susceptible mosquito populations of Culex pipiens or Aedes aegypti. However, it
partially restored (10 to 20 times) susceptibility of the resistant mosquito
populations of C. pipiens (SPHAE) and Culex quinquefasciatus (GeoR) to the binary
toxin. The Cyt1Ab1 protein produced in recombinant B. thuringiensis
SPL407(pcyt1Ab1) was synthesized in two types of crystal-one round and with
various dense areas, surrounded by an envelope, and the other a regular cuboid
crystal, very similar to that found in the B. sphaericus recombinant strain.
PMID- 9758820
TI - Occurrence of fusaproliferin and beauvericin in Fusarium-contaminated livestock
feed in Iowa.
AB - Fusarium fungal contaminants and related mycotoxins were investigated in eight
maize feed samples submitted to the Iowa State University Veterinary Diagnostic
Laboratory. Fusarium moniliforme, F. proliferatum, and F. subglutinans were
isolated from seven, eight, and five samples, respectively. These strains
belonged to mating populations A, D, and E of the teleomorph Gibberella
fujikuroi. Fusaproliferin was detected at concentrations of 0.1 to 30 microg/g in
four samples, and beauvericin was detected (0.1 to 3.0 microg/g) in five samples.
Fumonisins were detected in all eight samples (1.1 to 14 microg/g). Ten of 11
strains of F. proliferatum and all 12 strains of F. subglutinans isolated from
the samples produced fusaproliferin in culture on whole maize kernels (4 to 350
and 100 to 1,000 microg/g, respectively). Nine F. proliferatum strains also
produced beauvericin in culture (85 to 350 microg/g), but none of the F.
subglutinans strains produced beauvericin. Fumonisin B1 was produced by all nine
F. moniliforme strains (50 to 2,000 microg/g) and by 10 of the F. proliferatum
strains (1,000 to 2,000 microg/g). This is the first report of the natural
occurrence of fusaproliferin outside Italy and of the natural occurrence of
beauvericin in North America.
PMID- 9758819
TI - Physiological activity of Campylobacter jejuni far below the minimal growth
temperature.
AB - The behavior of Campylobacter jejuni at environmental temperatures was examined
by determining the physiological activities of this human pathogen. The minimal
growth temperatures were found to be 32 and 31 degrees C for strains 104 and ATCC
33560, respectively. Both strains exhibited a sudden decrease in growth rate from
the maximum to zero within a few degrees not only near the maximal growth
temperature but also near the minimal growth temperature. This could be an
indication that a temperature-dependent transition in the structure of a key
enzyme(s) or regulatory compound(s) determines the minimal growth temperature.
Oxygen consumption, catalase activity, ATP generation, and protein synthesis were
observed at temperatures as low as 4 degrees C, indicating that vital cellular
processes were still functioning. PCR analysis showed that cold shock protein
genes, which play a role in low-temperature adaptation in many bacteria, are not
present in C. jejuni. The fact that chemotaxis and aerotaxis could be observed at
all temperatures shows that the pathogen is able to move to favorable places at
environmental temperatures, which may have significant implications for the
survival of C. jejuni in the environment.
PMID- 9758821
TI - Bacterial stress responses to 1-megahertz pulsed ultrasound in the presence of
microbubbles.
AB - Members of a panel of stress-responsive biosensors have been used to study the
effect of megahertz frequency ultrasound on Escherichia coli. Insonification
causes acoustic cavitation, the collapse of oscillating microbubbles in solution,
which can damage bacterial cells. A focused 1-MHz ultrasound transducer, capable
of generating a spatial peak pulse average intensity of 500 W/cm2, was used to
treat liquid bacterial cultures. Stress-responsive promoters fused to luxCDABE
allowed the continuous measurement of light produced as a result of protein
damage, DNA damage, oxidative stress, and membrane perturbation. A promoter
responsive to ammonia limitation was not transcriptionally activated under test
conditions. In contrast to bacteria in exponentially growing cultures, those in
stationary-phase cultures were more resistant to the effects of ultrasound
treatment. Quantification of the degree of acoustic cavitation due to symmetric
bubble collapse was measured by a 20-MHz passive transducer, the output of which
appears to be only partially correlated with cellular damage and survival. The
methods and results summarized here provide the basis for further investigation
into applications, including the purification of water samples.
PMID- 9758822
TI - Optimization of Cry3A yields in Bacillus thuringiensis by use of sporulation
dependent promoters in combination with the STAB-SD mRNA sequence.
AB - The insecticidal activity of Bacillus thuringiensis strains toxic to coleopterous
insects is due to Cry3 proteins assembled into small rectangular crystals. Toxin
synthesis in these strains is dependent primarily upon a promoter that is active
in the stationary phase and a STAB-SD sequence that stabilizes the cry3
transcript-ribosome complex. Here we show that significantly higher yields of
Cry3A can be obtained by using dual sporulation-dependent cyt1Aa promoters to
drive the expression of cry3Aa when the STAB-SD sequence is included in the
construct. The Cry3A yield per unit of culture medium obtained with this
expression system was 12.7-fold greater than that produced by DSM 2803, the wild
type strain of B. thuringiensis from which Cry3Aa was originally described, and
1.4-fold greater than that produced by NB176, a mutant of the same strain
containing two or three copies of cry3Aa, which is the active ingredient of the
commercial product Novodor, used for control of beetle pests. The toxicities of
Cry3A produced with this construct or the wild-type strain were similar when
assayed against larvae of the cottonwood leaf beetle, Chrysomela scripta. The
volume of Cry3A crystals produced with cyt1Aa promoters and the STAB-SD sequence
was 1.3-fold that of typical bipyramidal Cry1 crystals toxic to lepidopterous
insects. The dual-promoter/STAB-SD system offers an additional method for
potentially improving the efficacy of insecticides based on B. thuringiensis.
PMID- 9758824
TI - Closely related plasmid replicons coexisting in the phytopathogen pseudomonas
syringae show a mosaic organization of the replication region and altered
incompatibility behavior
AB - Many Pseudomonas syringae strains contain native plasmids that are important for
host-pathogen interactions, and most of them contain several coexisting plasmids
(pPT23A-like plasmids) that cross-hybridize to replication sequences from pPT23A,
which also carries a gene cluster coding for the phytotoxin coronatine in P.
syringae pv. tomato PT23. In this study, three functional pPT23A-like replicons
were cloned from P. syringae pv. glycinea race 6, suggesting that the
compatibility of highly related replicons is a common feature of P. syringae
strains. Hybridization experiments using three separate incompatibility
determinants previously identified from pPT23A and the rulAB (UV radiation
tolerance) genes showed that the organization of the replication region among
pPT23A-like plasmids from several P. syringae pathovars is poorly conserved. The
putative repA gene from four pPT23A-like replicons from P. syringae pv. glycinea
race 6 was amplified by using specific primers. The restriction profiles of the
resulting PCR products for the race 6 plasmids were more similar to each other
than they were to that of pPT23A. These data, together with the existence of
other cross-hybridizing DNA regions around the replicon among the race 6 pPT23A
like plasmids, suggest that some of these plasmids may have originated from
duplication events. Our results also imply that modifications of the repA
sequences and the poor conservation of putative maintenance determinants
contribute to the suppression of incompatibility among members of the pPT23A-like
family, thus enhancing the genomic plasticity of P. syringae.
PMID- 9758825
TI - A new genetic locus in sinorhizobium meliloti is involved in stachydrine
utilization
AB - Stachydrine, a betaine released by germinating alfalfa seeds, functions as an
inducer of nodulation genes, a catabolite, and an osmoprotectant in Sinorhizobium
meliloti. Two stachydrine-inducible genes were found in S. meliloti 1021 by
mutation with a Tn5-luxAB promoter probe. Both mutant strains (S10 and S11)
formed effective alfalfa root nodules, but neither grew on stachydrine as the
sole carbon and nitrogen source. When grown in the absence or presence of salt
stress, S10 and S11 took up [14C]stachydrine as well as wild-type cells did, but
neither used stachydrine effectively as an osmoprotectant. In the absence of salt
stress, both S10 and S11 took up less [14C]proline than wild-type cells did. S10
and S11 appeared to colonize alfalfa roots normally in single-strain tests, but
when mixed with the wild-type strain, their rhizosphere counts were reduced more
than 50% (P = 0.01) relative to the wild type. These results suggest that
stachydrine catabolism contributes to root colonization. DNA sequence analysis
identified the mutated locus in S11 as putA, and the luxAB fusion in that gene
was induced by proline as well as stachydrine. DNA that restored the capacity of
mutant S10 to catabolize stachydrine contained a new open reading frame, stcD.
All data are consistent with the concept that stcD codes for an enzyme that
produces proline by demethylation of N-methylproline, a degradation product of
stachydrine.
PMID- 9758823
TI - Characterization of genes involved in biosynthesis of a novel antibiotic from
Burkholderia cepacia BC11 and their role in biological control of Rhizoctonia
solani.
AB - Genetic manipulation of fluorescent pseudomonads has provided major insight into
their production of antifungal molecules and their role in biological control of
plant disease. Burkholderia cepacia also produces antifungal activities, but its
biological control activity is much less well characterized, in part due to
difficulties in applying genetic tools. Here we report genetic and biochemical
characterization of a soil isolate of B. cepacia relating to its production of an
unusual antibiotic that is very active against a variety of soil fungi.
Purification and preliminary structural analyses suggest that this antibiotic
(called AFC-BC11) is a novel lipopeptide associated largely with the cell
membrane. Analysis of conditions for optimal production of AFC-BC11 indicated
stringent environmental regulation of its synthesis. Furthermore, we show that
production of AFC-BC11 is largely responsible for the ability of B. cepacia BC11
to effectively control the damping-off of cotton caused by the fungal pathogen
Rhizoctonia solani in a gnotobiotic system. Using Tn5 mutagenesis, we identified,
cloned, and characterized a region of the genome of strain BC11 that is required
for production of this antifungal metabolite. DNA sequence analysis suggested
that this region encodes proteins directly involved in the production of a
nonribosomally synthesized lipopeptide.
PMID- 9758826
TI - Relatedness of strains of xanthomonas fragariae by restriction fragment length
polymorphism, DNA-DNA reassociation, and fatty acid analyses
AB - The levels of relatedness of strains of Xanthomonas fragariae collected over
several years from locations in Canada and the United States were compared by
determining fatty acid methyl ester profiles, restriction fragment length
polymorphisms (RFLP) based on pulsed-field gel electrophoresis (PFGE) analysis,
and DNA-DNA reassociation values. Based on qualitative and quantitative
differences in fatty acid profiles, the strains were divided into nine groups and
four groups by the MIDI "10% rule" and unweighted pair analysis, respectively.
Restriction analysis of genomic DNA by PFGE with two endonucleases (XbaI and
SpeI) revealed four distinct profiles. When a third endonuclease (VspI) was used,
one group was divided into three subgroups. The profile of the American Type
Culture Collection type strain differed from the profile of every other strain of
X. fragariae. Considerable diversity was observed within X. fragariae, although
the majority of the strains represented a clonal population. The four groups
based on fatty acid profiles were similar to the four groups based on RFLP, but
neither method related groups to the geographic origins of the strains. The DNA
DNA reassociation values were high for representative strains, providing evidence
that all of the strains belong to the same species.
PMID- 9758827
TI - PCR-Based detection of the causal agent of watermark disease in willows (Salix
spp.)
AB - The watermark disease, caused by Brenneria salicis (formerly Erwinia salicis), is
of significant concern wherever tree-forming willows are grown or occur
naturally. The movement of infected, asymptomatic cuttings is a major cause of
pathogen dispersal. A reliable and sensitive diagnostic procedure is necessary
for the safe movement of willow planting material. We derived primers from the
nucleotide sequence of the 16S rRNA gene of B. salicis for the development of a
PCR to detect this pathogen. One set of primers, Es1a-Es4b, directed the
amplification of a 553-bp fragment from B. salicis genomic DNA as well as B.
salicis cells. PCR products were not observed when genomic DNA was tested for 27
strains of other, related plant-associated bacteria. Genomic fingerprinting by
amplification fragment length polymorphism of B. salicis strains, originating
from four different countries, and related Brenneria, Pectobacterium, and Erwinia
strains revealed a very high similarity among the B. salicis genomes, indicating
that the spread of the pathogen is mainly due to the transportation of infected
cuttings. The PCR had to be preceded by a DNA extraction in order to detect the
pathogen in the vascular fluid of willows. The minimum number of cells that could
be detected from vascular fluid was 20 CFU/ml. The PCR assays proved to be very
sensitive and reliable in detecting B. salicis in willow plant material.
PMID- 9758828
TI - Enzymatic conversion of glucose to UDP-4-keto-6-deoxyglucose in Streptomyces spp.
AB - All of the 2,6-dideoxy sugars contained within the structure of chromomycin A3
are derived from D-glucose. Enzyme assays were used to confirm the presence of
hexokinase, phosphoglucomutase, UDPG pyrophosphorylase (UDPGP), and UDPG
oxidoreductase (UDPGO), all of which are involved in the pathway of glucose
activation and conversion into 2,6-dideoxyhexoses during chromomycin
biosynthesis. Levels of the four enzymes in Streptomyces spp. cell extracts were
correlated with the production of chromomycins. The pathway of sugar activation
in Streptomyces spp. involves glucose 6-phosphorylation by hexokinase,
isomerization to G-1-P catalyzed by phosphoglucomutase, synthesis of UDPG
catalyzed by UDPGP, and formation of UDP-4-keto-6-deoxyglucose by UDPGO.
PMID- 9758829
TI - Construction of a range of derivatives of the biological control strain
agrobacterium rhizogenes K84: a study of factors involved in biological control
of crown gall disease
AB - The biological control strain Agrobacterium rhizogenes K84 is an effective agent
in the control of Agrobacterium pathogens, the causative agents of crown gall
disease. A number of factors are thought to play a role in the control process,
including production of the specific agrocins 84 and 434, which differ in the
spectra of pathogenic strains that they inhibit in vitro. A range of derivatives
of strain K84 has been developed with every combination of the three resident
plasmids, pAgK84, pAgK434, and pAtK84b, including a plasmid-free strain. These
derivatives produced either both, one, or neither of the characterized agrocins
84 and 434 and were isolated by plasmid curing, conjugation, and Tn5 transposon
mutagenesis. The ability of the derivative strains to inhibit gall formation on
almond roots was compared to that of the wild-type K84 parent. Treatment with the
plasmid-free derivative did not result in a significant level of control of an A.
rhizogenes pathogen based on numbers or dry weight of galls formed on injured
almond roots. The presence of plasmid pAgK84, pAgK434, or pAtK84b significantly
enhanced the biological control efficacy of K84 derivatives, and the highest
level of control was observed with strains harboring two or more plasmids. The
results observed with strains deficient in agrocin 434 production suggest that
this product may play an important role in the biological control of A.
rhizogenes pathogens. The involvement of plasmid pAgK84b in biological control
has not previously been reported. This study supports the conclusion that
multiple factors are involved in the success of strain K84 as a biological
control agent.
PMID- 9758831
TI - Molecular diversity of rhizobia occurring on native shrubby legumes in
southeastern australia
AB - The structure of rhizobial communities nodulating native shrubby legumes in open
eucalypt forest of southeastern Australia was investigated by a molecular
approach. Twenty-one genomic species were characterized by small-subunit
ribosomal DNA PCR-restriction fragment length polymorphism and phylogenetic
analyses, among 745 rhizobial strains isolated from nodules sampled on 32
different legume host species at 12 sites. Among these rhizobial genomic species,
16 belonged to the Bradyrhizobium subgroup, 2 to the Rhizobium leguminosarum
subgroup, and 3 to the Mesorhizobium subgroup. Only one genomic species
corresponded to a known species (Rhizobium tropici). The distribution of the
various genomic species was highly unbalanced among the 745 isolates, legume
hosts, and sites. Bradyrhizobium species were by far the most abundant, and
Rhizobium tropici dominated among the Rhizobium and Mesorhizobium isolates in the
generally acid soils where nodules were collected. Although a statistically
significant association occurred between the eight most common genomic species
and the 32 hosts, there was sufficient overlap in distributions that no clear
specificity between rhizobial genomic species and legume taxa was observed.
However, for three legume species, some preference for particular genomic species
was suggested. Similarly, no geographical partitioning was found.
PMID- 9758830
TI - A novel ATP-binding cassette transporter involved in multidrug resistance in the
phytopathogenic fungus Penicillium digitatum.
AB - Demethylation inhibitor (DMI)-resistant strains of the plant pathogenic fungus
Penicillium digitatum were shown to be simultaneously resistant to cycloheximide,
4-nitroquinoline-N-oxide (4NQO), and acriflavine. A PMR1 (Penicillium multidrug
resistance) gene encoding an ATP-binding cassette (ABC) transporter (P
glycoprotein) was cloned from a genomic DNA library of a DMI-resistant strain
(LC2) of Penicillium digitatum by heterologous hybridization with a DNA fragment
containing an ABC-encoding region from Botrytis cinerea. Sequence analysis
revealed significant amino acid homology to the primary structures of PMR1
(protein encoded by the PMR1 gene) and ABC transporters of Saccharomyces
cerevisiae (PDR5 and SNQ2), Schizosaccharomyces pombe (HBA2), Candida albicans
(CDR1), and Aspergillus nidulans (AtrA and AtrB). Disruption of the PMR1 gene of
P. digitatum DMI-resistant strain LC2 demonstrated that PMR1 was an important
determinant of resistance to DMIs. The effective concentrations inhibiting radial
growth by 50% (EC50s) and the MICs of fenarimol and bitertanol for the PMR1
disruptants (Deltapmr1 mutants) were equivalent to those for DMI-sensitive
strains. Northern blot analysis indicated that severalfold more PMR1 transcript
accumulated in the DMI-resistant strains compared with those in DMI-sensitive
strains in the absence of fungicide. In both DMI-resistant and -sensitive
strains, transcription of PMR1 was strongly enhanced within 10 min after
treatment with the DMI fungicide triflumizole. These results suggested that the
toxicant efflux system comprised of PMR1 participates directly in the DMI
resistance of the fungus.
PMID- 9758833
TI - Polymorphisms in phytophthora infestans: four mitochondrial haplotypes are
detected after PCR amplification of DNA from pure cultures or from host lesions
AB - Four pairs of primers were designed for PCR amplification of known polymorphic
regions of the mitochondrial genome of Phytophthora infestans. Digestion of the
amplified products with restriction enzymes allows identification of previously
identified haplotypes. Product P2 cut with MspI uniquely identifies haplotypes Ib
and IIa, while types Ia and IIb are differentiated by digestion of product P4
with EcoRI. Digestion of products P1 and P3 gave results similar to that with
digestion of P4, but amplification of these products was less robust. Thus, all
four common haplotypes are identified by amplifying and digesting products P2 and
P4. Identification of haplotypes was also possible from DNA extracted directly
from small, late-blight lesions on both tomato and potato leaves, making
isolation of the fungus unnecessary. A rapid and efficient method of monitoring
changes in the pathogen population is facilitated. These PCR primers were also
useful for differentiating other Phytophthora species.
PMID- 9758834
TI - A new operation for producing disease-suppressive compost from grass clippings
AB - This study evaluated the use of grass clippings discharged from golf courses as
the raw material for production of a suppressive compost to control Rhizoctonia
large-patch disease in mascarene grass. Bacillus subtilis N4, a mesophilic
bacterium with suppressive effects on the pathogenic fungus Rhizoctonia solani
AG2-2, was used as an inoculum in a procedure developed with the aim of
controlling composting temperatures and inoculation timing. The population
density of mesophilic bacteria in the raw material was reduced to around 5 log10
CFU/g (dry weight) of composting material in the self-heating reaction at the
initial stage of composting by maintaining a temperature of 80 degreesC for 1
day. The inoculum was applied immediately, and the composting material was
maintained at 40 degreesC for 3 days. This served both to highly concentrate the
suppressive bacterium and to achieve sporulation. The temperature was then raised
to 60 degreesC and maintained, enabling hygienic, high-speed composting while
maintaining the population density of the suppressive bacterium as high as 8
log10 CFU/g (dry weight) in the compost. The suppressiveness of compost made in
this way was confirmed in a turf grass disease prevention assay.
PMID- 9758832
TI - Isolation and identification of Helicobacter spp. from canine and feline gastric
mucosa.
AB - It is known that virtually all healthy adult dogs and cats harbor spiral
helicobacters in their gastric mucosa. Three species, Helicobacter felis,
Helicobacter bizzozeronii, and Helicobacter salomonis have been isolated in vitro
from the gastric mucosa of these animals. The aims of this study were to evaluate
the efficacy of an isolation method for canine and feline gastric helicobacters
that has been developed at the University of Helsinki; to estimate the prevalence
and distribution of these taxa in the samples examined; and to assess the
efficacy and validity of an extensive set of standardized conventional phenotypic
tests, whole-cell protein profiling, and ultrastructural analysis in identifying
the different species isolated from canine and feline gastric mucosa. We cultured
95 and 22 gastric mucosal biopsies from dogs and cats, respectively. Twenty-one
H. bizzozeronii strains, 8 H. felis strains, 8 H. salomonis strains, 3 mixed
cultures, 2 "Flexispira rappini"-like organisms, and 3 as yet uncharacterized
strains were isolated from the dogs, and 3 H. felis strains were isolated from
the cats. The methods used here yielded Helicobacter isolation rates of 51% from
dogs and 13.6% from cats, which exceed those reported previously. The main
difficulties were primary isolation, mixed cultures, and identification to the
species level. In the species identification, a detailed morphological
examination was found to yield important phenotypic characteristics. A large
panel of biochemical and tolerance tests did not clearly differentiate the
closely related species H. bizzozeronii, H. felis, and H. salomonis. Highly
standardized whole-cell protein profiling was shown to be an excellent method for
species identification. Improvements in culture conditions for these bacteria are
still needed, especially for cats. A genetic identification method not requiring
culture is needed for future studies of these very fastidious helicobacters, as
the clinical significance and ecology of these species within the gastric mucosa
of the domestic carnivores remain largely unknown.
PMID- 9758835
TI - Purification and substrate specificities of two alpha-L-arabinofuranosidases from
Aspergillus awamori IFO 4033.
AB - alpha-L-Arabinofuranosidases I and II were purified from the culture filtrate of
Aspergillus awamori IFO 4033 and had molecular weights of 81,000 and 62,000 and
pIs of 3.3 and 3.6, respectively. Both enzymes had an optimum pH of 4.0 and an
optimum temperature of 60 degreesC and exhibited stability at pH values from 3 to
7 and at temperatures up to 60 degrees C. The enzymes released arabinose from p
nitrophenyl-alpha-L-arabinofuranoside, O-alpha-L-arabinofuranosyl-(1-->3)-O-beta
D-xylopyranosyl-(1-->4)-D-x ylopyranose, and arabinose-containing polysaccharides
but not from O-beta-D-xylopyranosyl-(1-->2)-O-alpha-L-arabinofuranosyl-(1-->3)-O
b eta-D-xylopyranosyl-(1-->4)-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyra nose.
alpha-L-Arabinofuranosidase I also released arabinose from O-beta-D-xylopy
ranosyl-(1-->4)-[O-alpha-L-arabinofuranosyl- (1-->3)]- O-beta-D-xylopyranosyl-(1-
>4)-D-xylopyranose. However, alpha-L-arabinofuranosidase II did not readily
catalyze this hydrolysis reaction. alpha-L-Arabinofuranosidase I hydrolyzed all
linkages that can occur between two alpha-L-arabinofuranosyl residues in the
following order: (1-->5) linkage > (1-->3) linkage > (1-->2) linkage. alpha-L
Arabinofuranosidase II hydrolyzed the linkages in the following order: (1-->5)
linkage > (1-->2) linkage > (1-->3) linkage. alpha-L-Arabinofuranosidase I
preferentially hydrolyzed the (1-->5) linkage of branched arabinotrisaccharide.
On the other hand, alpha-L-arabinofuranosidase II preferentially hydrolyzed the
(1-->3) linkage in the same substrate. alpha-L-Arabinofuranosidase I released
arabinose from the nonreducing terminus of arabinan, whereas alpha-L
arabinofuranosidase II preferentially hydrolyzed the arabinosyl side chain
linkage of arabinan.
PMID- 9758836
TI - Identification, characterization, and In situ detection of a fruit-body-specific
hydrophobin of Pleurotus ostreatus.
AB - Hydrophobins are small (length, about 100 +/- 25 amino acids), cysteine-rich,
hydrophobic proteins that are present in large amounts in fungal cell walls,
where they form part of the outermost layer (rodlet layer); sometimes, they can
also be secreted into the medium. Different hydrophobins are associated with
different developmental stages of a fungus, and their biological functions
include protection of the hyphae against desiccation and attack by either
bacterial or fungal parasites, hyphal adherence, and the lowering of surface
tension of the culture medium to permit aerial growth of the hyphae. We
identified and isolated a hydrophobin (fruit body hydrophobin 1 [Fbh1]) present
in fruit bodies but absent in both monokaryotic and dikaryotic mycelia of the
edible mushroom Pleurotus ostreatus. In order to study the temporal and spatial
expression of the fbh1 gene, we determined the N-terminal amino acid sequence of
Fbh1. We also synthesized and cloned the double-stranded cDNA corresponding to
the full-length mRNA of Fbh1 to use it as a probe in both Northern blot and in
situ hybridization experiments. Fbh1 mRNA is detectable in specific parts of the
fruit body, and it is absent in other developmental stages.
PMID- 9758837
TI - Spatial physiological heterogeneity in Pseudomonas aeruginosa biofilm is
determined by oxygen availability.
AB - The role of oxygen availability in determining the local physiological activity
of Pseudomonas aeruginosa growing in biofilms was investigated. Biofilms grown in
an ambient-air environment expressed approximately 1/15th the alkaline
phosphatase specific activity of planktonic bacteria subjected to the same
phosphate limitation treatment. Biofilms grown in a gaseous environment of pure
oxygen exhibited 1.9 times the amount of alkaline phosphatase specific activity
of air-grown biofilms, whereas biofilms grown in an environment in which the air
was replaced with pure nitrogen prior to the inducing treatment did not develop
alkaline phosphatase activity. Frozen cross sections of biofilms stained for
alkaline phosphatase activity with a fluorogenic stain demonstrated that alkaline
phosphatase activity was concentrated in distinct bands adjacent to the gaseous
interfaces. These bands were approximately 30 micron thick with biofilms grown in
air, 2 micron thick with biofilms grown in pure nitrogen, and 46 micron thick
with biofilms grown in pure oxygen. Overall biofilm thickness ranged from
approximately 117 to approximately 151 micron. Measurements with an oxygen
microelectrode indicated that oxygen was depleted locally within the biofilm and
that the oxygen-replete zone was of a dimension similar to that of the
biologically active zone, as indicated by alkaline phosphatase induction. These
experiments revealed marked spatial physiological heterogeneity within P.
aeruginosa biofilms in which active protein synthesis was restricted by oxygen
availability to the upper 30 micron of the biofilm. Such physiological
heterogeneity has implications for microbial ecology and for understanding the
reduced susceptibilities of biofilms to antimicrobial agents.
PMID- 9758838
TI - Resistance to tellurite as a selection marker for genetic manipulations of
Pseudomonas strains.
AB - Resistance to the toxic compound potassium tellurite (Telr) has been employed as
a selection marker built into a set of transposon vectors and broad-host-range
plasmids tailored for genetic manipulations of Pseudomonas strains potentially
destined for environmental release. In this study, the activated Telr
determinants encoded by the cryptic telAB genes of plasmid RK2 were produced,
along with the associated kilA gene, as DNA cassettes compatible with cognate
vectors. In one case, the Telr determinants were assembled between the I and O
ends of a suicide delivery vector for mini-Tn5 transposons. In another case, the
kilA and telAB genes were combined with a minimal replicon derived from a variant
of Pseudomonas plasmid pPS10, which is able to replicate in a variety of gram
negative hosts and is endowed with a modular collection of cloning and expression
assets. Either in the plasmid or in the transposon vector, the Telr marker was
combined with a 12-kb DNA segment of plasmid pWW0 of Pseudomonas putida mt-2
encoding the upper TOL pathway enzymes. This allowed construction of antibiotic
resistance-free but selectable P. putida strains with the ability to grow on
toluene as the sole carbon source through an ortho-cleavage catabolic pathway.
PMID- 9758840
TI - A method for DNA extraction from the desert cyanobacterium chroococcidiopsis and
its application to identification of ftsZ
AB - A method was developed for extraction of DNA from Chroococcidiopsis that
overcomes obstacles posed by bacterial contamination and the presence of a thick
envelope surrounding the cyanobacterial cells. The method is based on the
resistance of Chroococcidiopsis to lysozyme and consists of a lysozyme treatment
followed by osmotic shock that reduces the bacterial contamination by 3 orders of
magnitude. Then DNase treatment is performed to eliminate DNA from the bacterial
lysate. Lysis of Chroococcidiopsis cells is achieved by grinding with glass beads
in the presence of hot phenol. Extracted DNA is further purified by cesium
chloride density gradient ultracentrifugation. This method permitted the first
molecular approach to the study of Chroococcidiopsis, and a 570-bp fragment of
the gene ftsZ was cloned and sequenced.
PMID- 9758839
TI - Specific cell wall proteins confer resistance to nisin upon yeast cells.
AB - The cell wall of a yeast cell forms a barrier for various proteinaceous and
nonproteinaceous molecules. Nisin, a small polypeptide and a well-known
preservative active against gram-positive bacteria, was tested with wild-type
Saccharomyces cerevisiae. This peptide had no effect on intact cells. However,
removal of the cell wall facilitated access of nisin to the membrane and led to
cell rupture. The roles of individual components of the cell wall in protection
against nisin were studied by using synchronized cultures. Variation in nisin
sensitivity was observed during the cell cycle. In the S phase, which is the
phase in the cell cycle in which the permeability of the yeast wall to
fluorescein isothiocyanate dextrans is highest, the cells were most sensitive to
nisin. In contrast, the cells were most resistant to nisin after a peak in
expression of the mRNA of cell wall protein 2 (Cwp2p), which coincided with the
G2 phase of the cell cycle. A mutant lacking Cwp2p has been shown to be more
sensitive to cell wall-interfering compounds and Zymolyase (J. M. Van der Vaart,
L. H. Caro, J. W. Chapman, F. M. Klis, and C. T. Verrips, J. Bacteriol. 177:3104
3110, 1995). Here we show that of the single cell wall protein knockouts, a Cwp2p
deficient mutant is most sensitive to nisin. A mutant with a double knockout of
Cwp1p and Cwp2p is hypersensitive to the peptide. Finally, in yeast mutants with
impaired cell wall structure, expression of both CWP1 and CWP2 was modified. We
concluded that Cwp2p plays a prominent role in protection of cells against
antimicrobial peptides, such as nisin, and that Cwp1p and Cwp2p play a key role
in the formation of a normal cell wall.
PMID- 9758841
TI - Comparison of a new thiomicrospira strain from the mid-atlantic ridge with known
hydrothermal vent isolates
AB - A new autotrophic Thiomicrospira strain, MA-3, was isolated from the surface of a
polymetal sulfide deposit collected at a Mid-Atlantic Ridge hydrothermal vent
site. The DNA homology among three vent isolates, Thiomicrospira crunogena,
Thiomicrospira sp. strain L-12, and Thiomicrospira sp. strain MA-3, was 99.3% or
higher, grouping them as the same species, T. crunogena (type strain, ATCC
35932). The fact that T. crunogena and Thiomicrospira sp. strain L-12 were
isolated from Pacific vent sites demonstrates a cosmopolitan distribution of this
species.
PMID- 9758842
TI - Activities of Bacillus thuringiensis insecticidal crystal proteins Cyt1Aa and
Cyt2Aa against three species of sheep blowfly.
AB - The toxicity of Bacillus thuringiensis Cyt1Aa protein to sheep blowfly larvae
depends on its solubilization and proteolytic activation. Cyt1Aa crystals were
not toxic. Full-length and trypsin-digested Cyt1Aa proteins were toxic to larvae
of three species of sheep blowfly. Neither full-length nor trypsin-digested Cyt2A
soluble crystal proteins were toxic.
PMID- 9758844
TI - Possible transmission of Streptococcus iniae from wild fish to cultured marine
fish.
AB - Streptococcus iniae was isolated from diseased wild fish collected near a
mariculture facility where gilthead sea bream and European sea bass exhibited a
similar infection. Species-specific PCR and ribotyping confirmed that wild and
cultured fish were infected by a single S. iniae clone. Wild fish are therefore
potential amplifiers of pathogenic S. iniae strains.
PMID- 9758843
TI - Use of phospholipid fatty acids and carbon source utilization patterns To track
microbial community succession in developing compost.
AB - Carbon source utilization and phospholipid fatty acid analyses were used to track
the rapidly changing microbial community in composting dairy waste. Microbial
abilities to utilize common plant sugars increased during composting. Community
phospholipid profiles changed significantly over time. Phospholipids suggested
the presence of more thermophiles and fewer bacteria with continued compost
development.
PMID- 9758845
TI - Development of bacterium-based heavy metal biosorbents: enhanced uptake of
cadmium and mercury by Escherichia coli expressing a metal binding motif.
AB - A gene coding for a de novo peptide sequence containing a metal binding motif was
chemically synthesized and expressed in Escherichia coli as a fusion with the
maltose binding protein. Bacterial cells expressing the metal binding peptide
fusion demonstrated enhanced binding of Cd2+ and Hg2+ compared to bacterial cells
lacking the metal binding peptide. The potential use of genetically engineered
bacteria as biosorbents for the removal of heavy metals from wastewaters is
discussed.
PMID- 9758846
TI - Purification and characterization of an NAD-malic enzyme from Bradyrhizobium
japonicum A1017.
AB - An NAD-malic enzyme was purified to homogeneity from Bradyrhizobium japonicum
A1017, and its molecular characteristics were surveyed. The enzyme exhibited
native and subunit molecular masses of 388 and 85 kDa, respectively, suggesting
that it exists as a homotetramer, and was activated by metabolic intermediates in
glycolysis. The role of the enzyme in bacteroids' carbon metabolism is discussed.
PMID- 9758847
TI - Balance of activities of alcohol acetyltransferase and esterase in Saccharomyces
cerevisiae is important for production of isoamyl acetate.
AB - Isoamyl acetate is synthesized from isoamyl alcohol and acetyl coenzyme A by
alcohol acetyltransferase (AATFase) in Saccharomyces cerevisiae and is hydrolyzed
by esterases at the same time. We hypothesized that the balance of both enzyme
activities was important for optimum production of isoamyl acetate in sake
brewing. To test this hypothesis, we constructed yeast strains with different
numbers of copies of the AATFase gene (ATF1) and the isoamyl acetate-hydrolyzing
esterase gene (IAH1) and used these strains in small-scale sake brewing.
Fermentation profiles as well as components of the resulting sake were largely
alike; however, the amount of isoamyl acetate in the sake increased with an
increasing ratio of AATFase/Iah1p esterase activity. Therefore, we conclude that
the balance of these two enzyme activities is important for isoamyl acetate
accumulation in sake mash.
PMID- 9758848
TI - A gliding bacterium strain inhibits adhesion and motility of another gliding
bacterium strain in a marine biofilm
AB - Two species of gliding bacteria were isolated from a marine biofilm. They were
described and identified as members of the genus Cytophaga. One of them (RB1057)
produced an extracellular inhibitor of colony expansion of the other (RB1058).
The inhibitor was characterized as a glycoprotein with an apparent molecular mass
of 60 kDa. It inhibited RB1058 adhesion to and gliding on substrata. Motility and
adhesion of several other aquatic gliding bacteria were not measurably affected
by this agent.
PMID- 9758850
TI - Evidence for interspecies gene transfer in the evolution of 2,4
dichlorophenoxyacetic acid degraders.
AB - Small-subunit ribosomal DNA (SSU rDNA) from 20 phenotypically distinct strains of
2,4-dichlorophenoxyacetic acid (2,4-D)-degrading bacteria was partially
sequenced, yielding 18 unique strains belonging to members of the alpha, beta,
and gamma subgroups of the class Proteobacteria. To understand the origin of 2,4
D degradation in this diverse collection, the first gene in the 2,4-D pathway,
tfdA, was sequenced. The sequences fell into three unique classes found in
various members of the beta and gamma subgroups of Proteobacteria. None of the
alpha-Proteobacteria yielded tfdA PCR products. A comparison of the dendrogram of
the tfdA genes with that of the SSU rDNA genes demonstrated incongruency in
phylogenies, and hence 2,4-D degradation must have originated from gene transfer
between species. Only those strains with tfdA sequences highly similar to the
tfdA sequence of strain JMP134 (tfdA class I) transferred all the 2,4-D genes and
conferred the 2,4-D degradation phenotype to a Burkholderia cepacia recipient.
PMID- 9758849
TI - Effective recovery of bacterial DNA and percent-guanine-plus-cytosine-based
analysis of community structure in the gastrointestinal tract of broiler
chickens.
AB - A DNA-based, direct method for initial characterization of the total bacterial
community in ileum and cecum of the chicken gastrointestinal (GI) tract was
developed. The efficiencies of bacterial extraction and lysis were >95 and >99%,
respectively, and therefore the DNA recovered should accurately reflect the
bacterial communities of the ileal and cecal digesta. Total bacterial DNA samples
were fractionated according to their percent G+C content. The profiles reflecting
the composition of the bacterial community were reproducible within each
compartment, but different between the compartments of the GI tract. This
approach is independent of the culturability of the bacteria in the consortium
and can be used to improve our understanding of how diet and other variables
modulate the microbial communities of the GI tracts of animals.
PMID- 9758852
TI - Synthesis of glycine betaine from exogenous choline in the moderately halophilic
bacterium halomonas elongata
AB - The role of choline in osmoprotection in the moderate halophile Halomonas
elongata has been examined. Transport and conversion of choline to betaine began
immediately after addition of choline to the growth medium. Intracellular
accumulation of betaine synthesized from choline was salt dependent up to 2.5 M
NaCl. Oxidation of choline was enhanced at 2.0 M NaCl in the presence or absence
of externally provided betaine. This indicates that the NaCl concentration in the
growth medium has major effects on the choline-betaine pathway of H. elongata.
PMID- 9758851
TI - Substrate selectivity and biochemical properties of 4-hydroxy-2-keto-pentanoic
acid aldolase from Escherichia coli.
AB - 4-Hydroxy-2-keto-pentanoic acid aldolase from Escherichia coli was identified as
a class I aldolase. The enzyme was found to be highly selective for the
acetaldehyde acceptor but would accept alpha-ketobutyric acid or phenylpyruvic
acid in place of the pyruvic acid carbonyl donor.
PMID- 9758853
TI - Loss of ammonia monooxygenase activity in nitrosomonas europaea upon exposure to
nitrite
AB - Nitrosomonas europaea, an obligate ammonia-oxidizing bacterium, lost an
increasing amount of ammonia oxidation activity upon exposure to increasing
concentrations of nitrite, the primary product of ammonia-oxidizing metabolism.
The loss of activity was specific to the ammonia monooxygenase (AMO) enzyme, as
confirmed by a decreased rate of NH4+-dependent O2 consumption, some loss of
active AMO molecules observed by polypeptide labeling with 14C2H2, the protection
of activity by substrates of AMO, and the requirement for copper. The loss of AMO
activity via nitrite occurred under both aerobic and anaerobic conditions, and
more activity was lost under alkaline than under acidic conditions except in the
presence of large concentrations (20 mM) of nitrite. These results indicate that
nitrite toxicity in N. europaea is mediated by a unique mechanism that is
specific for AMO.
PMID- 9758854
TI - Persistence of PCR-detectable Bacteroides distasonis from human feces in river
water.
AB - To evaluate the persistence of PCR-detectable Bacteroides distasonis in surface
water, whole human feces were dispersed into water from the Ohio River and
incubated in flasks in the laboratory or in diffusion chambers in situ. Duplicate
samples were taken daily, and material that pelleted at 16,000 x g was assayed by
PCR. Persistence of PCR-detectable DNA from this anaerobe depended upon
temperature and predation, two of the factors shown by others to influence the
survival of aerobic bacteria detected by culture. B. distasonis was detected by
PCR for at least 2 weeks at 4 degrees C but for only 4 to 5 days at 14 degrees C,
1 to 2 days at 24 degrees C, and 1 day at 30 degrees C. In filtered water or in
the presence of cycloheximide, a eukaryotic inhibitor, persistence at 24 degrees
C was extended by at least a week.
PMID- 9758855
TI - Oxidation of morphine to 2,2'-bimorphine by cylindrocarpon didymum
AB - The oxidation of morphine by whole-cell suspensions and cell extracts of
Cylindrocarpon didymum gave rise to the formation of 2, 2'-bimorphine. The
identity of 2,2'-bimorphine was confirmed by mass spectrometry and 1H nuclear
magnetic resonance spectroscopy. C. didymum also displayed activity with the
morphine analogs hydromorphone, 6-acetylmorphine, and dihydromorphine, but not
codeine or diamorphine, suggesting that a phenolic group at C-3 is essential for
activity.
PMID- 9758856
TI - Heat killing of Bacillus subtilis spores in water is not due to oxidative damage.
AB - The heat resistance of wild-type spores of Bacillus subtilis or spores (termed
alpha-beta-) lacking DNA protective alpha/beta-type small, acid-soluble spore
proteins was not altered by anaerobiosis or high concentrations of the free
radical scavenging agents ethanethiol and ethanedithiol. Heat-killed wild-type
and alpha-beta- spores exhibited no increase in either protein carbonyl content
or oxidized bases in DNA. These data strongly suggest that oxidative damage to
spore macromolecules does not contribute significantly to spore killing by heat.
PMID- 9758857
TI - Shedding light on voltage-dependent gating.
PMID- 9758858
TI - Protein rearrangements underlying slow inactivation of the Shaker K+ channel.
AB - Voltage-dependent ion channels transduce changes in the membrane electric field
into protein rearrangements that gate their transmembrane ion permeation
pathways. While certain molecular elements of the voltage sensor and gates have
been identified, little is known about either the nature of their conformational
rearrangements or about how the voltage sensor is coupled to the gates. We used
voltage clamp fluorometry to examine the voltage sensor (S4) and pore region (P
region) protein motions that underlie the slow inactivation of the Shaker K+
channel. Fluorescent probes in both the P-region and S4 changed emission
intensity in parallel with the onset and recovery of slow inactivation,
indicative of local protein rearrangements in this gating process. Two sequential
rearrangements were observed, with channels first entering the P-type, and then
the C-type inactivated state. These forms of inactivation appear to be mediated
by a single gate, with P-type inactivation closing the gate and C-type
inactivation stabilizing the gate's closed conformation. Such a stabilization was
due, at least in part, to a slow rearrangement around S4 that stabilizes S4 in
its activated transmembrane position. The fluorescence reports of S4 and P-region
fluorophore are consistent with an increased interaction of the voltage sensor
and inactivation gate upon gate closure, offering insight into how the voltage
sensing apparatus is coupled to a channel gate.
PMID- 9758859
TI - Structural implications of fluorescence quenching in the Shaker K+ channel.
AB - When attached to specific sites near the S4 segment of the nonconducting (W434F)
Shaker potassium channel, the fluorescent probe tetramethylrhodamine maleimide
undergoes voltage-dependent changes in intensity that correlate with the movement
of the voltage sensor (Mannuzzu, L.M., M.M. Moronne, and E.Y. Isacoff. 1996.
Science. 271:213-216; Cha, A., and F. Bezanilla. 1997. Neuron. 19:1127-1140). The
characteristics of this voltage-dependent fluorescence quenching are different in
a conducting version of the channel with a different pore substitution (T449Y).
Blocking the pore of the T449Y construct with either tetraethylammonium or
agitoxin removes a fluorescence component that correlates with the voltage
dependence but not the kinetics of ionic activation. This pore-mediated
modulation of the fluorescence quenching near the S4 segment suggests that the
fluorophore is affected by the state of the external pore. In addition, this
modulation may reflect conformational changes associated with channel opening
that are prevented by tetraethylammonium or agitoxin. Studies of pH titration,
collisional quenchers, and anisotropy indicate that fluorophores attached to
residues near the S4 segment are constrained by a nearby region of protein. The
mechanism of fluorescence quenching near the S4 segment does not involve either
reorientation of the fluorophore or a voltage-dependent excitation shift and is
different from the quenching mechanism observed at a site near the S2 segment.
Taken together, these results suggest that the extracellular portion of the S4
segment resides in an aqueous protein vestibule and is influenced by the state of
the external pore.
PMID- 9758861
TI - Subunit composition determines the single channel kinetics of the epithelial
sodium channel.
AB - We have further characterized at the single channel level the properties of
epithelial sodium channels formed by coexpression of alpha with either wild-type
beta or gamma subunits and alpha with carboxy-terminal truncated beta (betaT) or
gamma (gammaT) subunits in Xenopus laevis oocytes. alphabeta and alphabetaT
channels (9.6 and 8.7 pS, respectively, with 150 mM Li+) were found to be
constitutively open. Only upon inclusion of 1 microM amiloride in the pipette
solution could channel activity be resolved; both channel types had short open
and closed times. Mean channel open probability (Po) for alphabeta was 0.54 and
for alphabetaT was 0.50. In comparison, alphagamma and alphagammaT channels
exhibited different kinetics: alphagamma channels (6.7 pS in Li+) had either long
open times with short closings, resulting in a high Po (0.78), or short openings
with long closed times, resulting in a low Po (0. 16). The mean Po for all
alphagamma channels was 0.48. alphagammaT (6.6 pS in Li+) behaved as a single
population of channels with distinct kinetics: mean open time of 1.2 s and closed
time of 0.4 s, with a mean Po of 0.6, similar to that of alphagamma. Inclusion of
0. 1 microM amiloride in the pipette solution reduced the mean open time of
alphagammaT to 151 ms without significantly altering the closed time. We also
examined the kinetics of amiloride block of alphabeta, alphabetaT (1 microM
amiloride), and alphagammaT (0.1 microM amiloride) channels. alphabeta and
alphabetaT had similar blocking and unblocking rate constants, whereas the
unblocking rate constant for alphagammaT was 10-fold slower than alphabetaT. Our
results indicate that subunit composition of ENaC is a main determinant of Po. In
addition, channel kinetics and Po are not altered by carboxy-terminal deletion in
the beta subunit, whereas a similar deletion in the gamma subunit affects channel
kinetics but not Po.
PMID- 9758860
TI - Effects of spontaneous bilayer curvature on influenza virus-mediated fusion
pores.
AB - Cells expressing the hemagglutinin protein of influenza virus were fused to
planar bilayer membranes containing the fluorescent lipid probes
octadecylrhodamine (R18) or indocarbocyanine (DiI) to investigate whether
spontaneous curvature of each monolayer of a target membrane affects the growth
of fusion pores. R18 and DiI lowered the transition temperatures for formation of
an inverted hexagonal phase, indicating that these probes facilitate the
formation of negative curvature structures. The probes are known to translocate
from one monolayer of a bilayer membrane to the other in a voltage-dependent
manner. The spontaneous curvature of the cis monolayer (facing the cells) or the
trans monolayer could therefore be made more negative through control of the
polarity of voltage across the planar membrane. Electrical admittance
measurements showed that the open times of flickering fusion pores were shorter
when probes were in trans monolayers and longer when in cis monolayers compared
with times when probe was symmetrically distributed. Open times were the same for
probe symmetrically distributed as when probes were not present. Thus, open times
were a function of the asymmetry of the spontaneous curvature between the trans
and cis monolayers. Enriching the cis monolayer with a negative curvature probe
reduced the probability that a small pore would fully enlarge, whereas enriching
the trans monolayer promoted enlargement. Lysophosphatidylcholine has positive
spontaneous curvature and does not translocate. When lysophosphatidylcholine was
placed in trans leaflets of planar membranes, closing of fusion pores was rare.
The effects of the negative and positive spontaneous curvature probes do not
support the hypothesis that a flickering pore closes from an open state within a
hemifusion diaphragm (essentially a "flat" structure). Rather, such effects
support the hypothesis that the membrane surrounding the open pore forms a three
dimensional hourglass shape from which the pore flickers shut.
PMID- 9758862
TI - Permeation and gating of an inwardly rectifying potassium channel. Evidence for a
variable energy well.
AB - Permeation, gating, and their interrelationship in an inwardly rectifying
potassium (K+) channel, ROMK2, were studied using heterologous expression in
Xenopus oocytes. Patch-clamp recordings of single channels were obtained in the
cell-attached mode. The gating kinetics of ROMK2 were well described by a model
having one open and two closed states. One closed state was short lived
(approximately 1 ms) and the other was longer lived (approximately 40 ms) and
less frequent (approximately 1%). The long closed state was abolished by EDTA,
suggesting that it was due to block by divalent cations. These closures exhibit a
biphasic voltage dependence, implying that the divalent blockers can permeate the
channel. The short closures had a similar biphasic voltage dependence, suggesting
that they could be due to block by monovalent, permeating cations. The rate of
entering the short closed state varied with the K+ concentration and was
proportional to current amplitude, suggesting that permeating K+ ions may be
related to the short closures. To explain the results, we propose a variable
intrapore energy well model in which a shallow well may change into a deep one,
resulting in a normally permeant K+ ion becoming a blocker of its own channel.
PMID- 9758863
TI - Effect of membrane tension on gap junctional conductance of supporting cells in
Corti's organ.
AB - The effects of turgor pressure-induced membrane tension on junctional coupling of
Hensen cell isolates from the inner ear were evaluated by input capacitance or
transjunctional conductance measurement techniques. Turgor pressure was altered
by changing either pipette pressure or the osmolarities of extracellular
solutions. Both positive pipette pressure and extracellular applications of
hypotonic solutions, which caused cell size to concomitantly increase, uncoupled
the cells as indicated by reduced input capacitance and transjunctional
conductance. These changes were, in many cases, reversible and repeatable.
Intracellular application of 50 microM H-7, a broad-based protein kinase
inhibitor, and 10 mM BAPTA did not block the uncoupling effect of positive turgor
pressure on inner ear gap junctions. The transjunctional conductance at a holding
potential of -80 mV was 53.6 +/- 5.8 nS (mean +/- SEM, n = 9) and decreased
approximately 40% at a turgor pressure of 1.41 +/- 0.05 kPa. Considering the
coincident kinetics of cell deformation and uncoupling, we speculate that
mechanical forces work directly on gap junctions of the inner ear. These results
suggest that pathologies that induce imbalances in cochlear osmotic pressure
regulation may compromise normal cochlear homeostasis.
PMID- 9758864
TI - Intermediate conductances during deactivation of heteromultimeric Shaker
potassium channels.
AB - A previous study of the T442S mutant Shaker channel revealed activation-coupled
subconductance levels that apparently represent kinetic intermediates in channel
activation (Zheng, J., and F.J. Sigworth. 1997. J. Gen. Physiol. 110:101-117). We
have now extended the study to heteromultimeric channels consisting of various
numbers of mutant subunits as well as channels without mutant subunits, all in
the background of a chimeric Shaker channel having increased conductance. It has
been found that activation-coupled sublevels exist in all these channel types,
and are traversed in at least 80% of all deactivation time courses. In symmetric
K+ solutions, the currents in the two sublevels have a linear voltage dependence,
being 23-44% and 54-70% of the fully open conductance. Sublevels in different
channel types share similar voltage dependence of the mean lifetime and similar
ion selectivity properties. However, the mean lifetime of each current level
depends approximately geometrically on the number of mutant subunits in the
channel, becoming shorter in channels having fewer mutant subunits. Each mutant
subunit appears to stabilize all of the conducting states by approximately 0.5
kcal/mol. Consistent with previous results in the mutant channel, sublevels in
channels with two or no mutant subunits also showed ion selectivities that differ
from that of the fully open level, having relatively higher K+ than Rb+
conductances. A model is presented in which Shaker channels have two coupled
activation gates, one associated with the selectivity filter and a second
associated with the S6 helix bundle.
PMID- 9758865
TI - Nonindependent K+ movement through the pore in IRK1 potassium channels.
AB - We measured unidirectional K+ in- and efflux through an inward rectifier K
channel (IRK1) expressed in Xenopus oocytes. The ratio of these unidirectional
fluxes differed significantly from expectations based on independent ion
movement. In an extracellular solution with a K+ concentration of 25 mM, the data
were described by a Ussing flux-ratio exponent, n', of approximately 2.2 and was
constant over a voltage range from -50 to -25 mV. This result indicates that the
pore of IRK1 channels may be simultaneously occupied by at least three ions. The
IRK1 n' value of 2.2 is significantly smaller than the value of 3.5 obtained for
Shaker K channels under identical conditions. To determine if other permeation
properties that reflect multi-ion behavior differed between these two channel
types, we measured the conductance (at 0 mV) of single IRK1 channels as a
function of symmetrical K+ concentration. The conductance could be fit by a
saturating hyperbola with a half-saturation K+ activity of 40 mM, substantially
less than the reported value of 300 mM for Shaker K channels. We investigated the
ability of simple permeation models based on absolute reaction rate theory to
simulate IRK1 current-voltage, conductance, and flux-ratio data. Certain classes
of four-barrier, three-site permeation models are inconsistent with the data, but
models with high lateral barriers and a deep central well were able to account
for the flux-ratio and single channel data. We conclude that while the pore in
IRK1 and Shaker channels share important similarities, including K+ selectivity
and multi-ion occupancy, they differ in other properties, including the
sensitivity of pore conductance to K+ concentration, and may differ in the number
of K+ ions that can simultaneously occupy the pore: IRK1 channels may contain
three ions, but the pore in Shaker channels can accommodate four or more ions.
PMID- 9758866
TI - Mechanism of maxi-K channel activation by dehydrosoyasaponin-I.
AB - Dehydrosoyasaponin-I (DHS-I) is a potent activator of high-conductance, calcium
activated potassium (maxi-K) channels. Interaction of DHS-I with maxi-K channels
from bovine aortic smooth muscle was studied after incorporating single channels
into planar lipid bilayers. Nanomolar amounts of intracellular DHS-I caused the
appearance of discrete episodes of high channel open probability interrupted by
periods of apparently normal activity. Statistical analysis of these periods
revealed two clearly separable gating modes that likely reflect binding and
unbinding of DHS-I. Kinetic analysis of durations of DHS-I-modified modes
suggested DHS-I activates maxi-K channels through a high-order reaction. Average
durations of DHS-I-modified modes increased with DHS-I concentration, and
distributions of these mode durations contained two or more exponential
components. In addition, dose-dependent increases in channel open probability
from low initial values were high order with average Hill slopes of 2.4-2.9 under
different conditions, suggesting at least three to four DHS-I molecules bind to
maximally activate the channel. Changes in membrane potential over a 60-mV range
appeared to have little effect on DHS-I binding. DHS-I modified calcium- and
voltage-dependent channel gating. 100 nM DHS-I caused a threefold decrease in
concentration of calcium required to half maximally open channels. DHS-I shifted
the midpoint voltage for channel opening to more hyperpolarized potentials with a
maximum shift of -105 mV. 100 nM DHS-I had a larger effect on voltage-dependent
compared with calcium-dependent channel gating, suggesting DHS-I may
differentiate these gating mechanisms. A model specifying four identical,
noninteracting binding sites, where DHS-I binds to open conformations with 10-20
fold higher affinity than to closed conformations, explained changes in voltage
dependent gating and DHS-I-induced modes. This model of channel activation by DHS
I may provide a framework for understanding protein structures underlying maxi-K
channel gating, and may provide a basis for understanding ligand activation of
other ion channels.
PMID- 9758868
TI - [Val384Asp in hMLH1 gene in Chinese, Japanese and German and its etiological role
in colorectal cancer].
AB - OBJECTIVE: To investigate Va1384Asp of hMLH1 gene in Chinese, Japanese and German
after the missense mutation were identified in Chinese colorectal cancer patients
and to inquire into the etiological role of this mutation in colorectal cancer.
METHODS: Genomic DNA extracted from normal colon tissue or peripheral blood were
subjected to analysis in exon 12 of the hMLH1 gene by single strand conformation
polymorphism (SSCP) followed by DNA sequencing of aberrant bands in 26 Chinese
and 109 German colorectal cancer patients and in 80 healthy Chinese, 80 Japanese
and 100 German individuals . RESULTS: Va1384Asp in hMLH1 gene was found in 4 out
of 26 Chinese colorectal patients; 3 of them were out of the 9 patients with
colorectal cancer at young age (<50 years). Although 3 and 4 carriers of
Va1384Asp in hMLH1 gene were identified in 80 healthy Chinese and 80 healthy
Japanese individuals respectively, none were identified in German neither in 109
colorectal cancer patients, nor in 100 healthy German individuals. The frequency
of Va1384Asp in hMLH1 gene in the Chinese with colorectal cancer at young age was
higher than that in Chinese healthy individuals (P=0.013). CONCLUSION: Va1384Asp
can be taken as a polymorphism in hMLH1 gene in Chinese and Japanese populations
and may have a potential effect on age at onset of colorectal cancer.
PMID- 9758870
TI - [The microsatellite instability and loss of heterozygosity in chromosome
translocation breakpoint in leukemia].
AB - OBJECTIVE: To investigate the microsatellite instability (MSI) and loss of
heterozygosity (LOH) near the chromosome translocation breakpoints of various
types of leukemia. METHODS: PCR amplification of 11 microsatellite loci closely
linked to chromosome translocation breakpoints in 30 leukemia patients. RESULTS:
Twenty one in 30 cases of leukemia had MSI in from 1 to 14 microsatellite loci.
Eleven in 15 cases of acute leukemia had microsatellite instability (MSI) in more
than 1 locus; among them 4 cases had MSI in from 7 to 11 loci. In order of MSI
presence rate were D22S315>D9S179>D16S515>D8S559>D12S89. In six cases of chronic
myeloid leukemia, 4 cases had MSI in more than 3 loci. Thirteen (2/15) percent of
acute leukemia patients had loss of heterozygosity (LOH); the rate was higher
than that in other leukemia types. CONCLUSION: The results of MSI and LOH in many
cases indicate that there are a lot of allelic alterations in leukemia patients,
but those changes have no special relationship with chromosome translocation
breakpoints in various leukemia types.
PMID- 9758869
TI - [Establishment of partial gene expression map of 7q32 in nasopharyngeal carcinoma
and primary culture normal nasopharyngeal epithelial cells].
AB - OBJECTIVE: To establish partial gene expression map of 7q32 in nasopharyngeal
carcinoma (NPC) cell line, tissues and primary culture normal nasopharyngeal
epithelial cells. METHODS: We detected the expression of 20 ESTs at 7q32 in NPC
cell line HNE1,13 NPC biopsies and primary culture normal nasopharyngeal
epithelial cells using differential RT PCR and Northern hybridization. RESULTS: 8
ESTs (AA188181, AA13079,N27556, AA031919, N22721, H20825, T91284, AA001936)
expressed equally in both of HNE1 and primary culture normal nasopharyngeal
epithelial cells; 7 ESTs (T64215, AA025822, R60014,R80002,H06688, R60192,R95096)
expressed in neither of them; 3 ESTs (H19830,W72688,AA130630) overexpressed in
HNE1 ; and 2 ESTs (AA070437, H90882) overexpressed in primary culture normal
nasopharyngeal epithelial cells. W72688 and H19830 each overexpressed in
77%(10/13) of NPC biopsies; AA070437 down-expressed in 30.7% of NPC biopsies.
CONCLUSION: Partial gene expression map of 7q32 in nasopharyngeal carcinoma cell
line ,tissues and primary culture normal nasopharyngeal epithelial cells has been
established. The up-regulation of W72688, H19830 and down-regulation of AA070437
may be related to the occurrence of NPC.
PMID- 9758871
TI - [Loss of heterozygosity microsatellite DNA on chromosome loci 3, 5, 7, 9 and 18
in human pancreatic cancer].
AB - OBJECTIVE: Detecting the loss of heterozygosity in paraffin-embedded pancreatic
cancer tissues. METHODS: Analysing loss of heterzygosity (LOH) of microsatellite
DNA on chromosome loci 3,5,7,9 and 18 with PCR-SSLP-silver stain method in
pancreatic cancer. RESULTS: In 45 sporadic pancreatic cancer samples and their
paired control tissue, LOH was detected on site for D18S46( 18q21.1,31.0%),
D18S474 (18q21.1, 20.0%), D9S176 (9q22-31,20.0%), D3S1234 (3p14.2,17.5%),D 3S1289
(3p21.1, 15.7%), D3S1481 (3p14.2,4.9%), D7S486 (7q22,3.6%), D5S365 (5q32, 3.2%)
and D3S587 (3p24-26, 2.6%). CONCLUSION: Different percentages of loss of
heterzygosity on specific chromosomal regions were found, and the meaning of the
results was discussed. Some key genes may play a role in the pathogenesis of
pancreatic cancer.
PMID- 9758867
TI - Temperature dependence of voltage-gated H+ currents in human neutrophils, rat
alveolar epithelial cells, and mammalian phagocytes.
AB - H+ currents in human neutrophils, rat alveolar epithelial cells, and several
mammalian phagocyte cell lines were studied using whole-cell and excised-patch
tight-seal voltage clamp techniques at temperatures between 6 and 42 degrees C.
Effects of temperature on gating kinetics were distinguished from effects on the
H+ current amplitude. The activation and deactivation of H+ currents were both
highly temperature sensitive, with a Q10 of 6-9 (activation energy, Ea,
approximately 30-38 kcal/mol), greater than for most other ion channels. The
similarity of Ea for channel opening and closing suggests that the same step may
be rate determining. In addition, when the turn-on of H+ currents with
depolarization was fitted by a delay and single exponential, both the delay and
the time constant (tauact) had similarly high Q10. These results could be
explained if H+ channels were composed of several subunits, each of which
undergoes a single rate-determining gating transition. H+ current gating in all
mammalian cells studied had similarly strong temperature dependences. The H+
conductance increased markedly with temperature, with Q10 >/= 2 in whole-cell
experiments. In excised patches where depletion would affect the measurement
less, the Q10 was 2.8 at >20 degrees C and 5.3 at <20 degrees C. This temperature
sensitivity is much greater than for most other ion channels and for H+
conduction in aqueous solution, but is in the range reported for H+ transport
mechanisms other than channels; e.g., carriers and pumps. Evidently, under the
conditions employed, the rate-determining step in H+ permeation occurs not in the
diffusional approach but during permeation through the channel itself. The large
Ea of permeation intrinsically limits the conductance of this channel, and
appears inconsistent with the channel being a water-filled pore. At physiological
temperature, H+ channels provide mammalian cells with an enormous capacity for
proton extrusion.
PMID- 9758872
TI - [Detection of Hep-2 and hepatoma cell line chromosomal aberration by using
fluorescence in situ hybridization].
AB - OBJECTIVE: To study the chromosomal aberration of hepatoma cell line (1172) and
laryngocarcinoma cell line (Hep-2). METHODS: Fluorescence in situ hybridization
(FISH) was used with nine chromosomal special libraries. RESULTS: The abnormal
signals indicated that very complicated aberrations existed in the two cell
lines. This suggested that the aberrations also existed in other chromosomes not
yet studied. In 1172, the major type was structure aberration, but in Hep-2,
numerical abnormality was shown in almost all chromosomes studied. CONCLUSION:
Compared with traditional cytological methods, this technique has the advantages
of being quicker and more accurate and sensitive.
PMID- 9758873
TI - [Association between the debrisoquine hydroxylase gene polymorphism and the
genetic susceptibility of Parkinson's disease].
AB - OBJECTIVE: To clarify the relation of the debrisoquine hydroxylase gene
polymorphism with the genetic susceptibility of Parkinson's disease. METHODS: The
debrisoquine hydroxylase gene polymorphisms were analyzed with the polymerase
chain reaction-restriction fragment length polymorphism methods in 100 cases of
Parkinson's disease and 100 age-,sex-matched normal controls. RESULTS: It was
found that the frequencies of A and B mutation of debrisoquine hydroxylase gene
in group of patients were higher than those in the controls, and the risk of
suffering Parkinson's disease increased 2 times. In group of the patients, the
frequencies of C188-->T, G4268-->C and C2938-->T were also higher than those in
the controls. Especially in those with C2938-->T mutation, the risk of suffering
the disease increased 2.58 times. CONCLUSION: The result suggested that the
defect of the detoxifying enzymes might be a factor contributing to the genetic
susceptibility of Parkinson's disease.
PMID- 9758874
TI - [Identification of a mutation hotspot in exon 8 of Wilson's disease gene by cycle
sequencing].
AB - OBJECTIVE: To screen for mutation hotspot of Wilson's disease (WD) gene in
Chinese. METHODS: Cycle sequencing was used to detect mutation in exon 8 of WD
gene in 30 patients with WD. RESULTS: The same missense mutation, Arg778Leu, was
identified in 14 WD patients, four of which were homozygous and the others were
heterozygous for this mutation. The frequency of this mutation was 30%.
CONCLUSION: The codon 778(CGG-->CTG) of exon 8 in WD gene was one of mutation
hotspots in Chinese.
PMID- 9758875
TI - [A study of correlation between essential hypertension and HLA-DQA1 alleles].
AB - OBJECTIVE: To analyse the hereditary susceptibility by genotyping of HLA-DQA1
alleles in essential hypertensives. METHODS: The allelic types of HLA-DQA1 were
detected by PCR-SSP technic in 52 cases of essential hypertensives and 86 normal
individuals as the control. RESULTS: The frequency of HLA-DQA1*0302 allele in
hypertensive group was markedly higher than that in normal control group (17.9572
vs 3.5531), but the frequency of HLA-DQA1*0103 allele in normal group was higher
than that in hypertensive group. CONCLUSION: HLA-DQA1*0302 may be a correlative
gene of essential hypertension, whereas HLA-DQA1*0103 may be a defence gene of
hypertension.
PMID- 9758876
TI - [Expression of human SRY gene and the DNA-binding property of its product].
AB - OBJECTIVE: To investigate the role which human SRY gene plays in the regulation
of the downstream gene. METHODS: The fragment of SRY (sex determinating region on
the Y chromosome) HMG domain was cloned into the expressing vector pET-15b. The
hSRY gene recombinant plasmid-pETSY was transformed and expressed in E.coliBL21.
The target protein was purified by pET His. Tag system. The DNA-binding
retardation test and its competitive reaction were conducted between SRY protein
and the fragment of Mullerian inhibiting substance (MIS) promoter. RESULTS: The
molecular weight of the expressed hSRY protein was shown to be approximately
21kD. The specific DNA binding property of SRY protein to the fragment of MIS was
confirmed in the retardation test and its competitive reaction. CONCLUSION: The
results suggest that the product of SRY gene can bind the MIS promoter region and
may initiate the transcription of MIS.
PMID- 9758877
TI - [Genetic polymorphisms of TH01 and VWA loci in Tibetans in China].
AB - OBJECTIVE: To understand the genetic relationship between Han population and
Tibetan population, the genetic polymorphisms of two STR loci, TH01 and VWA were
studied in the Tibetans in China. METHODS: EDTA-blood specimens were collected
from 89 healthy unrelated Tibetan individuals in Lasa. DNA was extracted using
Chelex method. The DNA samples were amplified by PCR technique, and the PAGE
horizontal electrophoresis were used to typing the PCR products. RESULTS: There
were five alleles at TH01 locus in Tibetan population. The alleles frequencies
were TH01*6:0.097, TH01*7:0.227, TH01*8:0.091, TH01*9:0.481 and TH01*9.3:0.104. A
total of 12 genotypes were observed in 77 individuals for TH01. For VWA locus
there were seven alleles and the allele frequencies were VWA *14:0.101,
VWA*15:0.034, VWA*16:0.208, VWA*17:0.303, VWA*18:0.208, VWA*19:0.129 and
VWA*20:0.017. A total of 20 genotypes for VWA were observed in 89 individuals.
The results of test for Hardy-Weinberg equilibrium showed that the genotype
distributions observed at both STR loci were correspondent with those
expected(chi-square =7.421 df =8 P>0.05 for TH01; chi-square =19.61 df =14 P>0.05
for VWA). CONCLUSION: There is no significant difference between Han and Tibetan
populations in allele frequencies at TH01 and VWA loci. The results of analysis
using genetic distance and phylogenetic tree indicate that Tibetan population is
identical with Han population at TH01 and VWA loci .
PMID- 9758878
TI - [Comparison of genotype and intellectual phenotype in untreated phenylketonuric
children].
AB - OBJECTIVE: The main feature of phenylketonuria(PKU) is mental retardation.
Although classical PKU is defined as that the hepatic phenylalanine hydroxylase
(PAH) activity ranges 0-1% of normal enzyme, the untreated PKU patients show a
wide range of intellectual phenotype. This study sought to find the molecular
basis of such variation of intellectual phenotype among PKU. METHODS: 45
classical PKU patients included in the research were screened for detecting six
mutant alleles which were rather common among Chinese PKU patients, i.e. R243Q,
R413P, Y204C, Y356X, W326X and R111X. PCR-ASO and PCR-SSCP techniques were used.
The expression of those mutant PAH genes was analysed by methods of site-directed
mutagencies. 27 PKU patients whose two mutant alleles were both defined were
involved in this study. The IQ of these patients were tested by DDST system.
RESULTS: Among 27 patients, 4/27 (15%) were mild retardation, 10/27(37%) were
moderate, the severe mental retardation accounted for 12/27(44%). The
relationship between genotype and intellectual phenotype in this group was
examined. It was found that the intellectual phenotype of 8 patients were
compatible with genotype but not well matched in 19 cases. The enzyme activity of
Y204C expressed in vitro was 100%, but all 3 patients with Y204C/Y204C were
severely mental retarded. Enzyme activities of R413P and Y356X were <3% and 0
respectively in expression analysis, but the patients in this group had mild or
moderate mental retardation. CONCLUSION: Intellectual phenotype was not well
matched with the genotype in classical PKU patients, so that genotype can not be
used to predicte the intellectual phenotype in PKU patients.
PMID- 9758879
TI - [Relationship between methylenetetrahydrofolate reductase gene polymorphism and
coronary heart disease].
AB - OBJECTIVE: This study inquired into the relationship between
methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and coronary heart
disease. METHODS: By polymerase chain reaction and restriction fragment length
polymorphism (PCR-RFLP), MTHFR 677C-->T mutation was detected in 79 healthy
controls and 69 patients with coronary heart disease. RESULTS: The frequency of
MTHFR variant V677 of patients was significantly higher than that of healthy
controls (P<0.01). CONCLUSION: This study demonstrated that MTHFR gene V677
mutation was probably one of the genetic risk factors of coronary heart disease
and this provided a new basis for exploring the relevant pathogenesis.
PMID- 9758880
TI - [A family study of obsessive-compulsive disorder].
AB - OBJECTIVE: To explore the genetic etiology of obsessive-compulsive disorder (OCD)
and genetic association between OCD and tic disorder. METHODS: The mental
disorders in the first degree and second degree relatives of 90 probands with OCD
were investigated and compared with those of 100 healthy families by the method
of family genetic study. RESULTS: Compared to the control, the prevalence rates
of schizophrenia, affective disorder, minor depression, subclinical OCD, general
anxiety disorder and tic disorder in the first degree relatives of OCD were
elevated, except that of OCD. The prevalence rates of OCD and subclinical OCD,
general anxiety disorder, and other neurotic disorders in the first degree
relatives of patients with pure obsession were 47.6%, 35.7% and 23.8%,
respectively; compared to 10.8%, 3.6% and 0 in those of the control (P<0.01). The
prevalence rates of schizophrenia,affective disorder,and tic disorder in the
first degree relatives of OCD with tic were 52.0%, 26.0% and 90.9%, respectively;
compared to 0, 3.6% and 7.2% in those of the control (P<0.01). CONCLUSION: The
etiology of OCD is related to heredity. There was evidence to show genetic
association between OCD and tic disorder,The elevation of prevalence rates of
various mental disorders in the first degree relatives of OCD might suggest the
genetic basis of various subtypes of OCD.
PMID- 9758881
TI - [Screening mutations in phenylketonuria by means of nonradioactive reverse dot
blot hybridization].
AB - OBJECTIVE: To establish a simple, accurate and rapid method for screening of the
mutant genes in phenylketonuria (PKU). METHODS: Four exons harboring the
mutations, Y204C (exon6, E6), R243Q(E7), Y356X(E11) and R413P(E12), were
amplified by polymerase chain reaction (PCR) with incorporation of biotinylated
deoxynucleotide(biotinylated-11-dUTP or biotinylated-14-dCTP). Hybridization
between immobilized allele-specific oligonucleotide probes and biotin-labelled
amplified DNA was performed and nonradioactively detected by a colorimetric
reaction using streptavidin-alkaline phosphatase. RESULTS: The methods of non
radioactive reverse dot blot hybridization were established to screen the
mutations. We detected the genotypes of five PKU patients and found that three of
them carried R243Q mutation and one of the three also carried Y356X mutation.
These results were confirmed by PCR-single strand conformation polymorphism.
CONCLUSION: This method is suitable for rapid screening for common mutations in
Chinese PKU patients.
PMID- 9758882
TI - [PCR in combination with silver as a method for the determination of
apolipoprotein E alleles].
AB - OBJECTIVE: To present a rapid, sensitive and safe procedure for the determination
of human apolipoprotein E alleles. METHODS: Genomic DNA was extracted from 0.5ml
whole blood by a non-phenol protocol. After PCR and restriction enzyme
digestion,short DNA fragments were detected by a simplified silver staining
method. This technique was used to assay apolipoprotein E alleles in 19 patients
with sporadic Alzheimer's disease and 41 normal aged persons. RESULTS: The short
DNA fragments were visualized clearly on polyacrylamide gel processed by silver
staining. It took 24 hours from DNA extraction to the final result. The A4 allele
frequency in patients with sporadic Alzheimer's disease was 0.29, much higher
than that in control group (0.02, P<0.001). CONCLUSION: PCR in combination with
silver staining can satisfy the need for high-resolution and high-efficiency in
the determination of apolipoprotein E alleles and can be used as a routine
procedure in clinical and epidemiological investigations.
PMID- 9758883
TI - On the problem of adequate language in motor control.
AB - An adequate language is a prerequisite for progress in any area of science,
including movement science. Notions of structural units and synergies and the
principle of minimal interaction are revisited, discussed, and illustrated with a
few examples from recent studies. Equilibrium-point hypothesis is considered an
example of identifying significant variables in the control of a voluntary
movement.
PMID- 9758884
TI - Coactivation to reduce variability in the elderly.
AB - The aim of this experiment was to determine whether elderly persons exhibit
reciprocal phasing of muscle activity and scale EMG burst amplitude in the same
manner as young people. Seven young and 7 elderly adults performed 30( elbow
flexion movements at 800 ms duration to a visual target against varying inertial
loads. The elderly were not able to achieve the required movement duration as
frequently and spent a greater portion of the movement accelerating than the
young. The young and the elderly subjects scaled EMG burst amplitude to the
increasing loads in the same fashion, although the elderly subjects coactivated
the agonist/antagonist muscles more than did the young subjects and thus did not
accelerate the limb as rapidly. We hypothesized that the elderly used
coactivation to reduce movement variability, and we developed a single-joint
model with two muscles to examine this hypothesis. The model simulation correctly
predicted the variability reduction due to coactivation. It appears, however,
that this reduces the capability to accelerate rapidly.
PMID- 9758885
TI - Path curvature in workspace and in joint space: evidence for coexisting
coordinative rules in aiming.
AB - In this study we tried to establish whether point-to-point aiming movements are
planned in workspace, joint space, or both. Eight right-handed subjects performed
horizontal, vertical, and diagonal aiming movements on a transversal plane.
Movements were performed at several speeds. Curvature variations of the hand and
corresponding joint-space paths were investigated as a function of position,
direction, and speed. Straightness of hand paths predominated for vertical
movements but was systematically violated for horizontal and top-right to bottom
left movements. Furthermore, the hand-path curvature of the latter movements
increased with speed. Joint-space paths showed more deviation from a straight
line than hand paths except for top-left to bottom-right movements in which the
paths were equally curved. A comparison of normalized path curvatures at the hand
and joint level indicated that in aiming, the coordinative rule of straight-line
production seems to apply to both workspace and joint-space planning. The present
findings confirm Kawato's (1996) views that optimization processes operate
concurrently at the two control levels of arm-trajectory formation under study.
PMID- 9758886
TI - Grasp stiffness as a function of grasp force and finger span.
AB - The purpose of this study was to determine whether direct measurements of grasp
stiffness agreed with stiffness inferred from the slopes of isovolitional force
space characteristics derived from previous grasp-effort matching data. Grasp
stiffness for three-finger pinch was measured as a function of initial force and
finger span using step displacements applied in a do-not-intervene paradigm.
Subjects pinched a free-floating, motorized manipulandum in each hand and
squeezed both with equal effort; one of the hands was perturbed at random.
Stiffness was calculated from the initial and final steady-state values of force
and span. The effects of step amplitude, rise-time, and initial load stiffness
were investigated; grasp stiffness decreased significantly for larger steps,
increased slightly for longer rise-times, and was unaffected by load stiffness.
Grasp stiffness then was measured as a function of initial force and span using a
single set of step parameters. Stiffness increased significantly in proportion to
force but was changed only slightly by span. It was concluded that the
perturbation and effort-matching measures of stiffness are not equivalent and
represent different components of motor behavior.
PMID- 9758887
TI - The involvement of CD80 and CD86 costimulatory molecules in the induction of
eosinophilia in mice infected with Nippostrongylus brasiliensis.
AB - The costimulatory signal provided by the interaction between CD28 and its
ligands, CD80 and CD86, is critical for T cell activation. The requirement of
CD80 and CD86 in T cell activation for eosinophilia and IgE production was
examined in mice infected with the nematode parasite Nippostrongylus
brasiliensis. Combined treatment with anti-CD80 and anti-CD86 suppressed
eosinophilia in the blood and the small intestine and suppressed IgE production.
However, administration of either anti-CD80 or anti-CD86 alone had little effect
on eosinophilia and on the elevation of IgE levels. These results suggest that
CD80 and CD86 costimulation is required and either CD80 or CD86 can provide a
sufficient costimulatory signal for induction of eosinophilia in mice infected
with N. brasiliensis.
PMID- 9758888
TI - Identification of cDNA for rat homologues of human major basic protein and
eosinophil cationic protein.
AB - We have determined the complete nucleotide sequence for cDNA of rat homologues of
human eosinophil major basic protein (MBP) and eosinophil cationic protein (ECP)
using the rapid amplification of cDNA ends (RACE) procedure. Nucleotide sequence
of cDNA of rat MBP revealed that mRNA of rat MBP encodes a protein containing 227
amino acids which has three functional domains; namely, the signal peptide, the
acidic peptide that contains numerous acidic amino acids and the mature MBP, as
in human, guinea pig and mouse MBP. In addition, cDNA of a rat homologue of human
ECP was also cloned. The deduced amino acid sequence revealed that this gene
encodes a putative protein with a molecular weight of 15.5 kD which has
ribonuclease activity. The homology of amino acid sequence between the rat
homologue and the murine eosinophil-associated ribonucleases (EARs) was high
(65%). Therefore, we named this rat homologue 'rat EAR-1'.
PMID- 9758889
TI - Modulation of normal human eosinophil chemotaxis in vitro by herbimycin A,
erbstatin and pervanadate.
AB - BACKGROUND: The mediators involved in eosinophil accumulation in diseases such as
allergy continue to be an area of interest, even though little is known regarding
the signaling involved in the human cell type recruitment. In the present study,
we demonstrate a novel modulatory role of tyrosine kinase and tyrosine
phosphatase activities on normal human eosinophil chemotaxis induced by different
groups of chemoattractant. METHODS: Purified eosinophils were obtained from
normal healthy volunteers with the CD16-negative procedure. Chemotactic
activities against platelet-activating factor (PAF), vasoactive intestinal
peptide (VIP) and eotaxin were assessed using a 48-well microchemotaxis chamber
assay. Purified eosinophils were pretreated with herbimycin A, erbastatin or
pervanadate to examine the role of tyrosine kinase in chemoattractant signaling.
RESULTS: Pretreatment of eosinophils with the tyrosine kinase inhibitors
herbimycin A and erbstatin significantly blocked chemotaxis induced by eotaxin
whilst both inhibitors augmented chemotaxis induced by VIP; however, they had no
effect on PAF-induced chemotaxis. On the other hand, pretreatment of eosinophils
with the phosphotyrosine phosphatase inhibitor pervanadate resulted in
augmentation of eotaxin-induced chemotaxis and inhibition of VIP-induced
chemotaxis, but it had no effect on PAF-induced chemotaxis. CONCLUSIONS: These
results suggest that protein kinase plays a modulatory role in eosinophil
chemotaxis induced by various chemoattractants.
PMID- 9758890
TI - Blockade of CD28/B7 interaction suppresses allergic eosinophilic inflammation in
mice.
AB - To determine whether the costimulatory signal via CD28/B7 interaction is required
for causing allergic inflammation, we examined the effect of administration of
CTLA4-Ig, a fusion protein of the extracellular domain of CTLA4 and human IgG1
constant region, at the time of sensitization, on antigen-induced eosinophil
infiltration in the trachea of sensitized mice, on IL-2, IFN-gamma, IL-4 and IL-5
production in the airways of the mice and on antigen-specific IgE synthesis in
the mice. Administration of CTLA4-Ig at the time of sensitization suppressed
antigen-induced eosinophil infiltration into the trachea and antigen-specific IgE
production in mice. Furthermore, CTLA4-Ig administration at the time of
sensitization suppressed not only IL-2 production but also IFN&hyphengamma and
Th2 cytokine IL-4 and IL-5 production in the airways. Because allergic
inflammation requires CD4+ T cells producing Th2-type cytokines IL-4 and IL-5,
our results suggest that the costimulatory signal via CD28/B7 interaction is
important for the generation and activation of Th2 cells and thereby for the
development of allergic inflammation.
PMID- 9758891
TI - Effect of immunotherapy on the production of eosinophil adhesion-inducing
activity from mononuclear cells in house-dust-mite-sensitive bronchial asthma.
AB - An initial step of eosinophil (EOS) accumulation in the sites of allergic
inflammation is the adhesion to endothelial cells. There is increasing evidence
that immunotherapy (IT) modulates the production of cytokines from mononuclear
cells and hence attenuates allergic inflammation. To examine whether IT modifies
the production of factor(s) which induce EOS adhesion, peripheral blood
mononuclear cells (PBMC) from house-dust-mite-sensitive asthmatics treated with
or without IT were cultured for 96 h in the presence or absence of 1/microg/ml
Dermatophagoides farinae antigen. EOS were isolated from the peripheral blood of
healthy subjects. EOS adhesion-inducing activity (EAIA) in the PBMC culture
supernatants was examined by the ability to modify EOS adhesion to
paraformaldehyde-fixed human umbilical vein endothelial cells (HUVEC) which were
stimulated with IL-4 plus TNF-alpha. In asthmatics without IT, the addition of D.
farinae antigen significantly promoted the production of EAIA from PBMC (EOS
adhesion: 22.4+/-13.1% by medium control vs. 30.5+/-18.9% by D. farinae, n=10,
p=0.023). This enhancing effect was blocked by an anti-beta2-integrin antibody.
In contrast, the addition of D. farinae did not modulate EAIA production from
PBMC in asthmatics treated with IT (23.1+/-10.3% vs. 21.5+/-12.3%, n=10, p=NS).
These results suggest that IT induces the inhibition of antigen-dependent
production of EAIA from PBMC. This may contribute to the inhibitory effect of IT
on eosinophil recruitment in allergic inflammation.
PMID- 9758892
TI - IL-5-producing T cells that induce airway eosinophilia and hyperresponsiveness
are suppressed by dexamethasone and cyclosporin A in mice.
AB - We have recently demonstrated that airway eosinophilic inflammation can be
transferred to unprimed mice by infusion of IL-5-producing T cell clones. In this
study, we investigated the effects of dexamethasone and cyclosporin A on the
airway eosinophilic inflammation in mice transferred with T cell clones. An
ovalbumin-reactive T cell clone, KW29, produced IL-5 as well as IL-2 and IL-4
upon stimulation with relevant antigen. Dexamethasone and cyclosporin A dose
dependently suppressed the production of these cytokines in vitro. The number of
eosinophils recovered in the bronchoalveolar lavage fluid and the airway
responsiveness to acetylcholine were increased in KW29-transferred mice after
antigen provocation. Both responses were dose-dependently suppressed by the
administration of dexamethasone or cyclosporin A in vivo. We concluded that
airway eosinophilic inflammation can be controlled by agents capable of
downregulating IL-5 production in T cells.
PMID- 9758893
TI - Heterogeneous expression of tumor necrosis factor-alpha receptors I and II on
human peripheral eosinophils.
AB - BACKGROUND: Expression of the tumor necrosis factor-alpha receptor by human
eosinophils has not been determined. We examined the surface expression and mRNA
for tumor necrosis factor-alpha receptors I and II (TNF-alphaRI and TNF-alphaRII)
on peripheral eosinophils. METHODS: Eosinophils were obtained from 17 asthma
patients and 3 healthy volunteers. Flow cytometry was used to examine receptor
expression, and the reverse transcriptase-polymerase chain reaction was used to
examine receptor mRNA expression. RESULTS: Flow cytometry revealed that 16 out of
20 subjects had eosinophils expressing TNF-alphaRI and 18 subjects had
eosinophils expressing TNF-alphaRII. All eosinophils expressed at least one
receptor. The mRNA for TNF-alphaRII was detected in all eosinophils examined, but
the signals for TNF-alphaRI mRNA were only found in cells expressing this
receptor. CONCLUSIONS: Human peripheral eosinophils show heterogeneous expression
of TNF-alphaRI and TNF-alphaRII.
PMID- 9758894
TI - Altered expression of CD11b and CD62L after cross-linking of CD45 isoforms on
human eosinophils.
AB - BACKGROUND: Phosphotyrosine phosphatase CD45 is exclusively found on nucleated
hematopoietic cells. CD45 is an essential component of signaling of mast cel
degranulation and of lymphocyte activation, but little is known about its role in
eosinophils. In the present study, we have determined the expression and function
of CD45 isoforms on human eosinophils. METHODS: Expression of CD45 isoforms on
purified peripheral blood eosinophils was examined using indirect
immunofluorescence and flow cytometry. Eosinophils were cultured with anti-CD45
isoform monoclonal antibodies (mAbs) for up to 24 h. Eosinophil activation was
evaluated by measuring surface expression of CD11b or CD62L by flow cytometry.
RESULTS: Fresh eosinophils express CD45, CD45RB, CD45RO epitopes but not CD45RA.
Incubation with anti-CD45 isoform mAb for 30 min did not alter the expression of
either CD11b or CD62L on eosinophils. In contrast, the expression of CD11b was
significantly enhanced after 24 h of incubation with mAbs against CD45, CD45RB,
or CD45RO. In addition, the expression of CD62L was also significantly reduced
with anti-CD45RB and with anti-CD45RO mAbs. CONCLUSIONS: Cross-linking of surface
CD45 isoforms for 24 h significantly induced upregulation of CD11b expression and
CD62L shedding, consistent with activation of eosinophils. Our data suggest that
CD45 isoforms are functionally expressed on human eosinophils, and are capable of
modulating eosinophil function and might participate in allergic inflammation.
PMID- 9758895
TI - RANTES augments eosinophil lucigenin-dependent chemiluminescence.
AB - BACKGROUND: RANTES (regulated on activation, normal T expressed and secreted) has
been shown to possess chemotactic activity for eosinophils. Eosinophils have been
considered to play a key role in the allergic inflammation through the release of
inflammatory molecules such as radical oxygen products. Thus, in this study, we
examined the effect of RANTES on radical oxygen products from eosinophils.
METHODS: Eosinophils were isolated from heparinized venous blood of patients with
bronchial asthma by the modified CD16-negative depletion method. Radical oxygen
products were examined in terms of lucigenin-dependent chemiluminescence. To a
mixture of 50 microl of eosinophils (2x10(6)/ml) and 50 microl of lucigenin
(5x10(-4)M), 50 microl of calcium ionophore A23187 (final concentration 10(-5)M)
was added, and radical oxygen products were determined for 600 s. RESULTS: RANTES
treatment resulted in the enhancement of peak value (0.64+/-0.23 RLU) and
integrated value (119.08+/-20.52 RLU) as compared to untreated cells (0.15+/-0.03
RLU, 29.48+/-8.92 RLU, respectively). CONCLUSIONS We could conclude that RANTES
might play an important role in the pathogenesis of allergic inflammation through
involvement in selective eosinophil infiltration and eosinophil activation by
augmentation of eosinophil oxidative metabolism.
PMID- 9758896
TI - Involvement of beta1 and beta2 integrin stimulation in RNA synthesis in an
eosinophilic cell line (EoL-1).
AB - In allergic inflammatory disease, especially in bronchial asthma, eosinophils
play important roles as essential inflammatory cells. In the accumulation of
eosinophils in airway inflammation, eosinophils receive very diverse stimuli. In
this study, we investigated the influences of the signal between beta2
integrin/intercellular adhesion molecule-1 (ICAM-1) or beta1 integrin/fibronectin
(FN) and RNA synthesis on proteins in eosinophilic cell line-1 (EoL-1), using
recombinant soluble ICAM-1 (r-sICAM-1) as a global response of eosinophils. 3H
thymidine incorporation and 3H-uridine incorporation were used as indices for DNA
synthesis and RNA synthesis, respectively. In a comparison of the RNA/DNA ratio
with various durations of stimulation of 1 microg/ml of r-sICAM-1 and 100
microg/ml of FN, a time-dependent increase was observed, but the increase induced
by FN rose slower than that induced by r-sICAM-1. From this result, a beta2
integrin/ICAM-1 signal induced an increase in the RNA/DNA ratio in EoL-1,
implying that the signal promotes RNA synthesis, which suggests that various
types of protein synthesis, such as the synthesis of various cytokines, are
induced by the beta2 integrin/ICAM-1 signal. Similar results were obtained with a
beta1 integrin signal using FN, but there was a difference in the time course
between beta2 integrin/ICAM-1 and beta1 integrin/FN signals. This experimental
method may be useful for understanding these manifestations as a global response
of eosinophils.
PMID- 9758897
TI - Human skin mast cells produce TNF-alpha by substance P.
AB - Using in situ hybridization and the reverse transcriptase polymerase chain
reaction (RT-PCR) we show that messenger RNA for IL-4, IL-5 and tumor necrosis
factor-alpha (TNF-alpha) is induced by cross-linkage of high-affinity Fc(epsilon)
receptors (Fc(epsilon)RI) on human skin mast cells, but that only TNF-alpha mRNA
is selectively induced by substance P. Skin mast cells were purified using the
Percoll density technique. T cells were removed by serial negative selection
using a CD2 monoclonal antibody (mAb) to achieve a final mast cell purity >95%.
Purified mast cells were precultured with recombinant human stem cell factor
(rhSCF; 10 ng/ml) and myeloma IgE (3 microg/ml) for 16 h before challenge with
sheep polyclonal antihuman IgE antibody (anti-IgE; 1 or 10 microg/ml) in the
presence of rhSCF (50 ng/ml). Using in situ hybridization, we demonstrated that
IgE-dependent stimulation induces the expression of IL-4, IL-5 and TNF-alpha mRNA
in skin mast cells. We have investigated the expression of IL-4, IL-5 and TNF
alpha mRNA by substance P, with the result that substance P, 0.003-30 microM,
selectively induced TNF-alpha mRNA. However, substance P did not induce IL-4 mRNA
and did not enhance IL-5 mRNA. Furthermore, we confirmed the release of TNF-alpha
by substance P from skin mast cells using an ELISA technique. These findings
demonstrate the capacity of human skin mast cells to transcribe IL-4, IL-5 and
TNF-alpha by immunological activation and to transcribe and release TNF-alpha by
substance P.
PMID- 9758898
TI - Eosinophil degranulation in the presence of lung fibroblasts.
AB - BACKGROUND: Although eosinophils (Eos) and fibroblasts (Fb) are closely
approximated in the bronchial submucosae of asthmatics, and are believed to play
important roles in the pathogenesis of bronchial asthma, the interaction between
Eos and Fb has not been thoroughly elucidated. In this study, we have examined
eosinophil cationic protein (ECP) release from human Eos cultured in the presence
of human lung Fb. METHODS: Eos from healthy donors were cultured with or without
C5a for 16 h in the presence of human fetal lung Fb which had previously been
incubated with or without some cytokines for 4 h. ECP in supernatants was
measured by RIA. RESULTS: ECP release was potentiated only when both Eos and Fb
were activated by C5a and TNF, respectively, while it was not significantly
potentiated when either Eos or Fb were activated. ECP release from Eos activated
by C5a was also potentiated when Fb were stimulated by IL-1beta. The enhancement
of ECP release in cocultured Eos and Fb with stimulation was partly inhibited by
monoclonal antibodies against GM-CSF and was accompanied by the enhancement of
adhesion of Eos to Fb. CONCLUSIONS: This study shows that the stimulation of both
Eos and Fb increases ECP release. It is suggested that Fb may influence Eos
degranulation and play a role in the pathogenesis of bronchial asthma.
PMID- 9758899
TI - Human eotaxin induces eosinophil-derived neurotoxin release from normal human
eosinophils.
AB - BACKGROUND: Eosinophil granule proteins deposition at the site of allergic
inflammation contributes to the late-phase reaction of hypersensitivity diseases.
In the present communication, we describe the effect of human eotaxin on normal
human eosinophil exocytosis measured as degranulation of eosinophil-derived
neurotoxin (EDN). METHODS: Purified eosinophils were obtained from normal healthy
volunteers with the CD16-negative procedure. Purified eosinophils were stimulated
with various concentrations of eotaxin and the amount of EDN released was
analysed by radioimmunoassay. Flow cytometry was used to examine the surface
expression of adhesion molecules on eosinophils. RESULTS: Eotaxin significantly
induced EDN release in a dose-dependent manner. The potency of eotaxin in this
effect was equal to that of RANTES, and comparable to that of platelet-activating
factor. Eotaxin-induced EDN release was blocked by cytochalasin B in a dose
dependent manner. The surface expression of CD11a, CD11b, CD18 and VLA-4 adhesion
molecules on normal human eosinophils were not modulated by eotaxin stimulation.
CONCLUSIONS: These results indicate that eotaxin may play an important role not
only as a selective chemotaxin for the cell type but also as a secretagogue.
Furthermore, they demonstrate a degranulation mechanism(s) involving cytoskeletal
changes which is probably independent of the quantitative expression of adhesion
molecules.
PMID- 9758901
TI - Signal transduction in activation of human eosinophils: G protein-dependent and
independent pathways.
AB - Degranulation of eosinophils and subsequent release of toxic granule proteins
play a key role in allergic diseases such as bronchial asthma. We have previously
shown that stimulation of eosinophils with immobilized secretory immunoglobulin A
(sIgA) induced the phosphorylation of several proteins including 51-, 65-, 73-,
78-, 100-, 105- and 113-kD proteins. Pervanadate, a protein tyrosine phosphatase
inhibitor, also induced at least 7 tyrosine phosphorylated proteins including
those observed with immobilized sIgA. Pervanadate also induced inositol phosphate
(IP) production and degranulation of eosinophils in a concentration-dependent
manner. Eosinophil production of IP and degranulation as well as tyrosine
phosphorylation of proteins induced by sIgA were completely inhibited by a
tyrosine kinase inhibitor, genistein, and pertussis toxin (PTX), suggesting the
involvement of both the PTX-sensitive guanine nucleotide-binding (G) protein and
protein tyrosine kinases (PTK) in sIgA-induced activation of eosinophils. In
contrast, PTX did not affect tyrosine phosphorylation induced by sIgA or
pervanadate. Furthermore, pervanadate-induced IP production was partially
inhibited by PTX. Finally, a phospholipase C-gamma2 isoform was tyrosine
phosphorylated by pervanadate, but not by sIgA. These findings suggest that at
least two different pathways, i.e. PTK-mediated G protein-dependent or
independent PLC activation, are involved in the activation of human eosinophils.
PMID- 9758900
TI - Suppressive effects of SP-A on ionomycin-induced IL-8 production and release by
eosinophils.
AB - Recent studies have demonstrated that pulmonary surfactant protein (SP)-A plays a
potential role in modifying inflammation and immune function. To see whether SP-A
could modify IL-8 production and release by eosinophils stimulated with
ionomycin, SP-A purified from surfactant recovered from patients with alveolar
proteinosis was added to eosinophils isolated by the negative-selection method
with immunomagnetic beads, and cultured for 24 h. The concentrations of IL-8 in
the cell-free supernatants and cell lysates were then measured by ELISA. SP-A
attenuated the production of IL-8 by eosinophils in a concentration-dependent
manner. SP-A also attenuated the release of IL-8 from the eosinophils. The
addition of SP-A antibody (PE10) reversed these effects of SP-A completely. These
data suggest that SP-A may have the potential to modify allergic inflammation by
inhibiting the release and production of IL-8 by eosinophils.
PMID- 9758902
TI - Cross-linking of the beta2 integrin, CD11b/CD18, on human eosinophils induces
protein tyrosine phosphorylation and cellular degranulation.
AB - Adhesion molecules, including integrins, play an important role in the selective
recruitment of eosinophils. It has recently been shown that integrins also
modulate the functions of eosinophils. Here, we tested the hypothesis that cross
linking of the beta2 integrin, alphaMbeta2Mac-/, leads to intracellular signaling
events such as activation of protein tyrosine kinases leading to eosinophil
degranulation. Cross-of cell surface CD11b/with anti-tibody and goat anti-G
immobilized onto the plate triggered tyrosine phosphorylation of several
intracellular proteins, including the one with a 115-kD mass (pp115). The same
stimulus also provoked degranulation of eosinophils. These findings suggest that
engagement of beta2 integrin on eosinophils triggers the activation of
intracellular signaling cascade which leads to cellular degranulation.
PMID- 9758903
TI - Interferon-gamma receptor beta-chain expression and formation of alpha- and beta
chain complexes after receptor conjugation on human peripheral eosinophils.
AB - BACKGROUND: It has been unclear whether or not the interferon-gamma receptor (IFN
gammaR) on human peripheral eosinophils is completely functional. Accordingly, we
examined the expression of IFN-gammaR alpha- and beta-chains and the association
of the two chains after binding of IFN-gamma to the receptor. METHODS: Peripheral
blood eosinophils were obtained from 8 patients (bronchial asthma, n=6, and
hypereosinophilic syndrome, n=2), and expression of the alpha- and beta-chain was
investigated by flow cytometry with specific antibodies. Expression of mRNA for
the alpha- and beta-subunits was also investigated by the reverse transcriptase
polymerase chain reaction. RESULTS: Eosinophils from all the patients were
positive for both the alpha- and beta-chains by flow cytometry. In addition, mRNA
for both chains was detected by the polymerase chain reaction. Furthermore,
coprecipitation of the alpha- and beta-chains was only found after eosinophil
stimulation with IFN-gamma. CONCLUSIONS: Human peripheral eosinophils apparently
express both the alpha- and beta-chains of the IFN-gammaR, and the two chains may
only form the receptor complex after ligand binding.
PMID- 9758904
TI - Whole-blood flow-cytometric analysis of eosinophil EG2 expression as a marker of
the pathological conditions of asthma.
AB - Using a simple technique detecting the eosinophil fraction in whole-blood flow
cytometry, we measured intracellular antigen EG2 (a monoclonal antibody to
eosinophil cationic protein) in 56 asthmatic patients (26 during an attack and 30
during an asymptomatic period) and 22 healthy subjects to determine whether EG2
reflects the pathological stages of allergy. METHODS: In brief, preparations of
the sample included the following procedures: (1) hemolyzation of heparinized or
EDTA-mixed whole blood; (2) fixation of white blood cells with 0.4%
parabenzoquinone (PBQ) or paraformaldehyde (PFA); (3) permeabilizing the cell
membrane with n-octyl-beta-D-glucopyranoside, and (4) staining of intracellular
EG2 antigen with monoclonal EG2 antibody and FITC-labeled secondary antibody.
RESULTS: In PBQ-fixed samples, there was a clearer boundary of the eosinophil
fraction with a higher yield and purity than in those fixed with PFA. The number
of EG2-positive eosinophils was significantly greater in subjects during attacks
than in asymptomatic patients. In addition, when compared with normal controls,
asthmatic subjects had significantly greater numbers of EG2-positive eosinophils
regardless of their current condition. CONCLUSION: Eosinophil intracellular EG2
may indicate the pathological stage of asthma. This simple technique for
analysing the properties of eosinophils using whole-blood flow cytometry would
save time and labor in laboratories.
PMID- 9758905
TI - Glutamatergic neurotransmission in alcoholism.
PMID- 9758906
TI - HLA-E is the ligand for the natural killer cell CD94/NKG2 receptors.
PMID- 9758907
TI - The radiation-sensitive costimulatory factors involved in B-cell-dependent T-cell
activation by minor lymphocyte stimulating antigen.
PMID- 9758908
TI - A novel regulator inhibits HBV gene expression.
PMID- 9758909
TI - Patterns of circulating hepatitis B surface antigen variants among vaccinated
children born to hepatitis B surface antigen carrier and non-carrier mothers. A
population-based comparative study.
PMID- 9758910
TI - Quantitative examination of the cardiac myocytes in hypertensive rats under
chronic inhibition of nitric oxide synthesis.
PMID- 9758911
TI - Characterization of a phage specific to hemorrhagic Escherichia coli O157:H7 and
disclosure of variations in host outer membrane protein ompC.
PMID- 9758954
TI - Physiologically relevant one-compartment pharmacokinetic models for skin. 1.
Development Of models
PMID- 9758955
TI - The capitation debate.
PMID- 9758912
TI - Retroviral transfer of antisense sequences results in reduction of C-Abl and
induction of apoptosis in hemopoietic cells.
PMID- 9758956
TI - Issues to consider in dental managed care programs.
PMID- 9758957
TI - Blood-filled spaces with and without filler materials in guided bone
regeneration. A comparative experimental study in the rabbit using bioresorbable
membranes.
AB - The aim of the present study was to evaluate the effect of natural deproteinized
bone mineral on the temporal and spatial pattern of bone formation in a guided
bone regeneration model system while using a bioresorbable membrane device. A
periosteal skin flap was raised uncovering the calvaria of 20 rabbits. A stiff
hemispherical dome made of polylactic acid was placed onto the roughened calvaria
and anchored by screws. Prior to placement, the dome was either filled with
peripheral blood (control group, 8 rabbits) or with blood and OsteoGraf/N-300
(test group, 12 rabbits). At 1 month, histologic sections revealed bone
regeneration in both test and control domes to various degrees. In the test
domes, bone height reached 78% (67-83) and bone volume was 11% (6-17), while in
the control domes, bone height was 45% (14-67) and bone volume 6% (1-11). At 2
months, bone height was unchanged in the test group at 70% (67-83) and bone
volume had only slightly increased to 16% (11-21). In the controls, height
increased to 86% (60-100) and volume to 20% (9-27). Thus, in this model system,
natural bone mineral fill contributed to accelerate initial bone neogenesis,
while it did not contribute to increasing bone volume or bone height at later
observation stages.
PMID- 9758958
TI - Bone augmentation at titanium implants using autologous bone grafts and a
bioresorbable barrier. An experimental study in the rabbit tibia.
AB - The aim of the present investigation was to compare the effect of using
autologous bone particles covered with a bioresorbable matrix barrier with the
use of bone particles alone on bone augmentation at titanium implants installed
in the rabbit tibia. Two Branemark System implants, one in each tibia, were
inserted in each of 9 rabbits in such a way that 5 threads were not covered with
bone. Autologous bone particles were harvested from the skull and placed over the
exposed implant surfaces on each tibia. The bone graft on one tibia was covered
with a Guidor Matrix Barrier, while the bone graft on the other tibia served as a
control. After a healing period of 12 weeks, the animals were sacrificed and
specimens taken for histomorphometrical analyses. The analyses showed that a
significantly larger volume of augmented bone tissue had formed at the test
sites. There were, however, no differences in the amount of mineralized bone. In
fact, the difference in tissue volume was due to an increased amount of bone
marrow at the test sites. The degree of mineralized bone to implant contact as
well as the degree of mineralized bone within the threads at the test implants
were similar to that at the controls. In conclusion, it was found that the
coverage of particulate autologous bone grafts with a bioresorbable barrier
resulted in a larger volume of augmented bone than the use of bone grafts not
covered with a barrier.
PMID- 9758959
TI - Augmentation of skull bone using a bioresorbable barrier supported by autologous
bone grafts. An intra-individual study in the rabbit.
AB - The aim of this experimental investigation was to compare the effect of using
autologous particulate bone grafts with and without a bioresorbable barrier
covering for augmentation of the rabbit skull bone. For this purpose, bilateral,
circular, 8 mm wide and 1 mm deep skull bone defects were prepared and overfilled
with particulate bone grafts. The grafts placed in the test sites were covered
with a bioresorbable barrier (Guidor Matrix Barrier). The grafts placed in the
control sites were covered only by the repositioned, cutaneous flap. 12 weeks
later, the animals were sacrificed, the experimental sites were defleshed and the
height and volume of the augmented bone in the test and control sites were
measured clinically. Histologically, morphometrical measurements of the bone
tissue were performed in decalcified vertical cross-sections of the experimental
sites. Statistically significant differences were found in favour of the coverage
of the bone graft particles with the barrier, both with respect to the height and
the volume of the augmented bone.
PMID- 9758960
TI - Bioactive glass and calcium carbonate granules as filler material around titanium
and bioactive glass implants in the medullar space of the rabbit tibia.
AB - The effect of bioactive glass (BG) and calcium carbonate (CC) granules on bone
formation around titanium and BG implants projecting into the medullary space of
rabbit tibia was studied. The bone marrow tissue was removed and the medullary
space was filled either with BG or CC (Biocoral) granules (phi 630-800 microns).
Conical titanium and BG implants were inserted into the holes drilled in compact
bone using the press fit-technique. Histomorphometry was used to measure the bone
biomaterial area in a 1.0 mm wide zone around the head of the implant and the
contact between formed bone and implant. Significantly larger bone-biomaterial
area was obtained around titanium implants using BG than CC granules while no
difference was found in connection of BG implants. Better bone-implant contact
was achieved with BG implants than with titanium implants regardless of the type
of granules used. The results indicate that BG may prove to be useful as filler
and coating material in connection of implants projecting into bone cavities.
PMID- 9758961
TI - Morphological and dimensional changes after barrier removal in bone formed beyond
the skeletal borders at titanium implants. A kinetic study in the rabbit tibia.
AB - The aim of the present experimental investigation was to study the morphological
and dimensional changes of bone, augmented at titanium implants by a membrane
technique, taking place after membrane removal. In 12 rabbits, screw-shaped
titanium implants were inserted in the tibial metaphyses in such a way that 5
threads became uncovered with bone. Surgery was performed on 2 occasions in order
to retrieve specimens with different follow-up times. An e-PTFE barrier and a
titanium device were used to provide space for bone formation. In 1 tibia of each
rabbit, the membranes and spacers were removed after 8 weeks of healing, and the
implants followed for 16 more weeks. Impressions were taken at day 0 and after 8
and 24 weeks of healing and plaster models were produced. In the contralateral
tibiae, implants were inserted either 16 or 8 weeks prior to sacrifice.
Measurements were made on the plaster models in 3 dimensions at 35 points around
each implant in a coordinate measuring machine. Specimens taken 8, 16 and 24
weeks after insertion were analysed by means of light microscopical morphometry.
The coordinate measurements showed that, in mean, 1.92 mm of bone had been formed
during the first 8 weeks. A statistically significant loss of the height of the
newly formed bone (0.70 mm) and thereby reduction of bone volume was found 24
weeks postoperatively. The volume decrease of the newly formed bone was more
pronounced beside the implants than over the implant body. The histology showed
that woven bone had been formed at the implants after 8 weeks. Further bone
formation and remodelling and a net increase of mineralized bone were seen. The
degree of bone-implant contact and bone area in the threads increased with time.
The present study showed that coordinate measurements on plaster models, obtained
from the experimental areas, in combination with histology, form a useful
technique to study long-term changes of augmented bone. It was found that bone
formed by a barrier membrane technique, decreased in volume during a 16-week
follow-up period after barrier removal. Less dimensional changes were observed
for the bone formed over the implant body, indicating that a solid surface may
have a stabilizing effect on the augmented bone.
PMID- 9758962
TI - Healing around implants placed in bone defects treated with Bio-Oss. An
experimental study in the dog.
AB - The aim of the present experiment was to (i) study the healing after 3 and 7
months of bone defects filled with cancellous bovine bone mineral and (ii)
compare the healing around implants placed in normal bone and in defects filled
with bovine bone mineral. 5 beagle dogs, about 1-year-old, were used. At
baseline, extractions of all mandibular left and right premolars were performed.
Bone defects were prepared in the left mandibular quadrant. The defect was
immediately filled with natural bovine cancellous bone mineral particles (Bio
Oss, Geistlich Sons Ltd. Wolhusen, Switzerland). No resective surgery was
performed in the right jaw quadrant. In both quadrants the flaps were adjusted to
allow full coverage of the edentulous ridge and sutured. 3 months later, 2 dogs
(group I) were euthanized and biopsies from the premolar regions obtained and
prepared for histologic analysis. The 3 remaining dogs (group II) were at this
time interval (3 months) subjected to implant installation in the premolar region
of both the right and left mandibular jaw quadrants. 2 fixtures of the ITI Dental
Implant System (Straumann, Waldenburg, Switzerland; solid-screw; 8 x 3.3 mm) were
installed in each side. The fixtures in the test side were placed within the
previously grafted defect area, while the fixtures in the control side were
placed in normally healed extraction sites. A 4 month period of plaque control
was initiated. At the end of this period, a clinical examination including
assessment of plaque and soft tissue inflammation was performed and radiographs
obtained from the implant sites. Biopsies were harvested and 4 tissue samples
were yielded per dog, each including the implant and the surrounding soft and
hard peri-implant tissues. The biopsies were processed for ground sectioning or
"fracture technique" and the sections produced were subjected to histological
examination. The volume of the hard tissue that was occupied by clearly
identified Bio-Oss particles was reduced between the 3- and 7-month intervals.
This indicates that with time, Bio-Oss becomes integrated and subsequently
replaced by newly formed bone. In other words, this xenograft fulfils the
criteria of an osteoconductive material. It was also observed that 4 months after
implant installation, the titanium/hard tissue interface at test and control
sites exhibited, from both a quantitative and qualitative aspect, a similar
degree of "osseointegration".
PMID- 9758963
TI - Characteristics of the cancellous bone of edentulous mandibles.
AB - Trabecular bone volume and trabecular connectivity (trabecular bone pattern
factor) of edentulous mandibles were examined using undecalcified bone sections
from the region of the 1st premolar to investigate atrophy-related changes in
mandibular cancellous bone. The mean trabecular bone volume was 21.8% in female
mandibles and 36.6% in male mandibles. The mean trabecular bone pattern factor
was -0.22 mm-1 for female mandibles and -2.29 mm-1 for male mandibles. The
difference between the sexes was statistically conspicuous for both parameters,
but did not attain statistical significance. A notable fact was the extreme range
of variation in both trabecular bone volume and trabecular connectedness. A
difference of 65% between the highest and the lowest trabecular bone volumes
measured in the present study (min, 7.6%; max, 73.6%, both male) reflects the
possible variation in trabecular density of edentulous mandibles.
PMID- 9758964
TI - Orthodontic anchorage capacity of short titanium screw implants in the maxilla.
An experimental study in the dog.
AB - The aim of this study was to investigate experimentally the effect of long term
orthodontic loading on the stability as well as on the peri-implant bone findings
of short titanium screw implants (Bonefit, submersion depth 6 mm, phi 4 mm)
inserted in regions with reduced vertical bone height. For this purpose, 6
maxillary premolars (1P1, 2P2, 3P3) were extracted from each of 2 foxhounds and
reduction of alveolar bone height was performed by osteotomy. After a 16-week
healing period, 8 implants (4 per dog) were inserted in the edentulous areas.
Simultaneously, 2 implants (1 per dog) were positioned in the palatal suture (one
stage surgery). After an 8-week implant healing period, the fixtures in the P1/P2
areas (n = 4) and the palate (n = 2) were loaded (test implants) by means of
transpalatal bars running anteriorly, fixed on the implants in the P1/P2 areas,
and Sentalloy traction springs (approximately 2 N continuous force) inserted
midsagittally between palatal implants and bars (force application period: 26
weeks). The fixtures in the P2/P3 areas served as controls (n = 4). Clinical
measurements and histological evaluation revealed no implant dislocation of the
loaded fixtures. These results suggest that short titanium screw implants
inserted in the alveolar bone and palatal suture region retain their stability
during long-term orthodontic loading, even following a relatively short unloaded
implant healing period. Furthermore, it seems that long-term orthodontic loading
may induce marginal bone apposition adjacent to the implants.
PMID- 9758965
TI - Force distribution on implants supporting overdentures: the effect of distal bar
extensions. A 3-D in vivo study.
AB - Force distribution on mandibular implants supporting overdentures was registered
in vivo by means of piezo-electric transducers that allow for simultaneous force
measurements in 3 dimensions. The anchorage device for connecting the overdenture
to the implants was a U-shaped bar to which distal extensions were soldered
bilaterally. Force patterns were analyzed under different test conditions such as
maximum force when biting in centric occlusion, maximum biting with the
unilateral use of a bite plate, parafunction and chewing bread. Maximum force
measured in centric occlusion and on the ipsilateral implant with the use of bite
plate was increased in the vertical dimension, compared to transverse dimensions.
On the contralateral implant, equally low values were found, in all 3 dimensions.
Transverse force components reached 5 to 35% of the vertical magnitudes. With the
use of the bite plate on the ipsilateral implant, force magnitudes in the
vertical direction and in the backward-forward direction were significantly
higher (P < 0.01, P < 0.00) compared to measurements in centric occlusion.
Chewing and grinding resulted in lower vertical forces compared to maximum
biting, while transverse forces in the backward forward direction reached force
magnitudes that resembled the vertical component (50 to 100%). The prevalent (>
95%) or exclusive force direction in the vertical dimension, registered on both
implants was downward. However, with the unilateral use of the bite plate, upward
directions were found on the contralateral implant as an effect of distal bar
extensions. This was in contrast to previous results where upward force
directions were not found. In transverse dimensions, the specific influence of
bar extensions was recognised in backward directions on the contralateral
implant. In comparison with previous results, it was concluded that, in vivo, the
effect of distal bar extensions was of much lesser influence regarding force
magnitudes and force directions than was expected.
PMID- 9758966
TI - Polymerization contraction stress in thin resin composite layers as a function of
layer thickness.
AB - OBJECTIVES: In the present study, the effect of layer thickness on the curing
stress in thin resin composite layers was investigated. Since the value of the
contraction stress is dependent on the compliance of the measuring equipment
(especially for thin films), a method to determine the compliance of the test
apparatus was tested. METHODS: A chemically initiated resin composite (Clearfil
F2, Kuraray) was inserted between two sandblasted and silane-coated stainless
steel discs in a tensilometer. The curing contraction of the cylindrical samples
was continuously counteracted by feedback displacement of the tensilometer
crosshead, and the curing stress development was registered. After 20 min, the
samples were loaded in tension until fracture. The curing stress was determined
for layer thicknesses of 50, 100, 200, 300, 400, 500, 600, 700 microns, 1.4 mm
and 2.7 mm. The compliance of the apparatus was calculated with the aid of a non
linear regression analysis, using an equation derived from Hooke's Law as the
model. RESULTS: None of the samples fractured due to contraction stress prior to
tensile loading. The contraction stress after 20 min decreased from 23.3 +/- 5.3
MPa for the 50 microns layer to 5.5 +/- 0.6 MPa for the 2.7 mm layer. The
compliance on the apparatus was 0.029 mm/MPa. SIGNIFICANCE: A measuring method
was developed which was found to be suitable for the determination of axial
polymerization contraction stress in this films of chemically initiated resin
composites. The method makes it possible to estimate the stress levels that occur
in resin composite films in the clinical situation.
PMID- 9758967
TI - Fracture toughness and load relaxation of dentin bonding resin systems.
AB - OBJECTIVES: The fracture toughness (KIC) and load relaxation of four dentin
bonding resins were determined to characterize some of the mechanical properties
of these materials after polymerization. METHODS: A total of 40 single-edge notch
bar specimens were fabricated, 10 each of four commercially available brands, and
subjected to three-point bending until fracture, as described in ASTM Standard
E399-83 (1991a). The critical stress intensification factor, KIC, was derived for
each specimen and compared by analysis of variance and Scheffe's multiple
comparisons test (p < 0.01). To study the load relaxation characteristics, five
rectangular specimens (without notches) of each brand were subjected to three
point loading until a predetermined limiting load value was reached. The test
load was allowed to relax for 4 min, after which the specimen was unloaded to the
zero load condition, and the load was allowed to build up on its own accord for 3
min. Load relaxation values were measured from the chart, and the mean percent
load drop was calculated. The load relaxation data were compared using analysis
of variance and Scheffe's multiple comparisons test (p < 0.05). RESULTS: The
fracture toughness (KIC) values of the four adhesive resins studied in this
investigation ranged from 0.37-0.94 MPa.m0.5 and were statistically different
from each other (p < 0.001). The load relaxation values were found to be greatest
within the first 0.5 min, with the total load relaxation of the four bonding
agents ranging from 16%-30%. Two of the materials studied showed significantly
different short-term load relaxation behavior than the other two resins (p <
0.05). SIGNIFICANCE: Bonding agents can be implicated as one of the factors that
weaken the interface between the dentin and the composite restorative material.
These materials are capable of a rapid short-term response, demonstrating
significant load relaxation in the first 0.5 min after loading.
PMID- 9758969
TI - Surface analysis of nickel-titanium archwire used in vivo.
AB - OBJECTIVES: The surface quality of an archwire is a critical factor in the
prevention of corrosion. This study was conducted to evaluate and assess the
surface of as-received and used nickel-titanium archwires for evidence of
corrosion, and to analyze possible corrosion products. METHODS: Round 0.4 mm and
square 0.4 mm x 0.55 mm nickel-titanium archwires from two manufacturers were
subjected to elemental analysis, examined, and photographed in a scanning
electron microscope with an EDAX unit. The used wires had been in service from 3
wk to 4 mon. There were no systematic differences in surface topography or
composition between the as-received and used wires. RESULTS: The examination
revealed undulated surfaces with manufactural scratches and crevices. The surface
quality within the same archwire varied slightly, with different smoothness in
the anterior and posterior regions. No systematic discernible difference was
found between used and as-received arch wires. The analyses of different areas on
the used archwires revealed no differences in the metal composition.
SIGNIFICANCE: The surface defects found on the as-received wires were evidently
not large enough to act as sites for corrosion attack.
PMID- 9758968
TI - Resistance of cementum in Class II and V cavities to penetration by an adhesive
system.
AB - OBJECTIVES: As the cervical margin located in cementum-dentin is still the most
unpredictable area of an adhesive resin restoration, the aim of this
investigation was to evaluate the morphology of the cementum layer at the
cervical margins of Class V and Class II cavities and the impregnability of this
layer to resin bonding systems. METHODS: Three different types of in vitro
investigations of the cervical margins were performed by scanning electron
microscopy: 1) direct anatomical observation of conditioned cavities; 2)
observation of resin replicas; and 3) observation of resin infiltration. During
direct observation, the presence of opened tubules was evaluated; in the resin
replicas, the presence of resin tags and their density were observed; in the
observation of resin infiltration, the presence of an acid-resistant
interdiffusion was investigated. RESULTS: From direct observation, cut tubules
were seen 200 microns from the cervical margin. After treatment with a dentin
bonding system, the outer layer was infiltrated by the resin. In the resin
replica, the presence of resin tags was detectable 150-200 microns from the
margin. In Class II samples, the presence of an outer layer at the cervical
margin, which could not be identified as bulk dentin or cementum, was clearly
detectable by both direct and indirect observation. In the Class V samples, the
border between this layer and bulk dentin was less evident. SIGNIFICANCE: The
presence of a cementum layer of approximately 150-200 microns at the cervical
margins of cavities may pose a serious clinical problem for reliable bonding.
Although in the present study the observation of a zone of resin-impregnated
cementum may confirm the improvement obtained with the last generation of
hybridizing dentin bonding systems, the effectiveness of the bond is still
unclear.
PMID- 9758970
TI - In vitro cytotoxicity of amalgams made with binary Hg-In liquid alloys.
AB - OBJECTIVE: Mercury vapor release from amalgams during setting significantly
decreases when the amalgams are prepared with binary Hg-In liquid alloys. The
objective of this study was to compare the cytotoxicity of amalgams made with
experimental Hg-In alloys with that of amalgam without In and a commercial In
containing amalgam. METHODS: Amalgam specimens were prepared by triturating a
high-Cu alloy powder (Tytin, Kerr) with pure Hg or Hg-In liquid alloy containing
5, 20 or 50% In and also by triturating an In-containing high-copper alloy powder
(Indiloy, Shofu) with pure Hg. After the specimens were aged for 2 wk, a
cylindrical specimen of each amalgam was immersed consecutively in cell culture
medium for 0-8, 8-48 and 48-72 h. The cytotoxicity of the extracts was determined
by placing them in contact with Balb/c 3T3 mouse fibroblasts for 24 h, after
which the succinic dehydrogenase (SDH) activity was measured and expressed as a
percentage of the Teflon negative controls. The results were statistically
compared using ANOVA and Tukey's test (alpha = 0.05). The concentration of
elements released into the extracts was determined by atomic absorption
spectrophotometry and evaluated by Kruskal-Wallis and nonparametric multiple
comparisons. RESULTS: For the 0-8 h and 8-48 h intervals, the 20% In amalgam was
significantly (p < 0.05) less toxic than the other amalgams, and not different
from the Teflon control. Results for the other amalgams were only slightly
depressed compared to the Teflon control. For the 48-72 h interval, all amalgams
were essentially no different from the control. Copper was the element dominantly
released into the medium from all the amalgams tested. SIGNIFICANCE: For amalgam
tested after aging, alloying indium to mercury did not deleteriously affect the
cytotoxicity of the resultant amalgam compared to the amalgam without indium.
PMID- 9758971
TI - Coating of silicone-based impression materials in a glow-discharge system by
acrylic acid plasma.
AB - OBJECTIVES: The main purpose of this study was to demonstrate an increase in the
wettability of silicone-based impression materials after coating them with a
hydrophilic film in a glow-discharge system. METHODS: Two vinyl polysiloxane
impression materials, Extrude (Kerr) and Accuflex (GC America Inc.) were used.
Impression specimens were treated in a glow-discharge reactor at a radio
frequency of 13.56 MHz at different discharge powers (5-20 W) and exposure times
(5-60 min). Surface analysis of the specimens was done by FTIR. Surface contact
angles were obtained by a captive-bubble method. These results were analyzed by
ANOVA and Duncan's Multiple Range test (p < 0.05). The total number of voids on
the die stone casts was observed microscopically. Linear dimensional accuracy,
detail reproducibility, and surface hardness of the die stone casts were also
determined. A Student t-test was performed for statistical analysis of these
parameters (p > 0.05). RESULTS: FTIR spectra indicated that the number of
hydroxyl groups on the surfaces increased (p > 0.05) because of the glow
discharge treatment. Contact angle measurements showed an increase (p < 0.05) in
surface hydrophilicity. Total void formation in the stone casts decreased. There
were no significant differences in the linear dimensional accuracy, detail
reproducibility, and hardness, before and after glow-discharge treatment (p >
0.05). SIGNIFICANCE: It was concluded that the surface wettability of the
impression materials may be increased by plasma deposition, and therefore, the
formation of voids was reduced in the stone casts.
PMID- 9758972
TI - Color distribution of three regions of extracted human teeth.
AB - OBJECTIVES: Knowledge of human tooth color and its distribution are critical to
the understanding of shade matching in esthetic dentistry. The color of human
teeth shows a gradation from the gingival to the incisal region. There have been
many reports in the literature on the distribution of color in teeth, but not in
the CIE 1976 L*a*b* system. This study was conducted to determine the color
distribution in three regions in a sample of human teeth and express the results
in Munsell notation, CIE 1976 L*a*b* and CIE delta E* color differences. The
hypothesis of this research was that it is possible to detect significant
differences in the color parameters of the three distinct regions in teeth.
METHODS: All of the teeth used in this study were extracted, cleaned and stored
in artificial saliva. Prior to measurement, the teeth were removed from the
solution and mounted in a holder to ensure consistent measurements. Spectral data
were collected using a GE recording spectrophotometer, CIE chromaticity
coordinates calculated using CIE illuminant C and 1931 observer data, and
conversions made to L*, a*, b* and Munsell notation. The results were analyzed by
ANOVA and Scheffe's multiple comparisons test. RESULTS: The mean L*, a*, b*s were
72.6, 1.5, 18.4 for gingival, 72.4, 1.2, 16.2 for middle, and 71.4, 0.9, 12.8 for
incisal. Average Munsell parameters were 1.2 Y 7.1/2.7 for gingival, 1.3 Y
7.1/2.4 for middle, and 1.4 Y 7.0/1.9 for incisal. The mean CIE delta E* between
the gingival and incisal regions of the 95 teeth showed a clinically significant
difference of 8.2. SIGNIFICANCE: The distribution of color was identified for
three regions of the tooth. A statistical analysis determined that there are
statistically significant color differences between the regions, and these
differences are also clinically significant. This information is beneficial when
esthetic restorations are required.
PMID- 9758973
TI - The determination of working time and gelation time of temporary soft lining
materials.
AB - OBJECTIVE: The purpose of this study was to establish a new method for the
determination of working time and gelation time of temporary soft lining
materials using a displacement rheometer. METHOD: A displacement rheometer (The
Dental School, University of Newcastle, Newcastle upon Tyne, UK) was used to
apply a rapid displacement of 0.25 mm held for 1 s at intervals of 60 s to
samples of four temporary soft lining materials. Material displacement and
elastic recovery at each test time was recorded. The test procedure was repeated
three times at 23 degrees C and at 37 degrees C for each material. For one
material, the displacement time was varied (1, 5, 10 s). The working time was
defined as the time corresponding to the initial observation of elastic recovery
at 23 degrees C. Gelation time was the time when a material achieved 95% of its
maximum elastic recovery at 37 degrees C. Values were compared between materials
using one-way analysis of variance and Student-Newman-Keuls test at the 5% level
of significance. RESULTS: The gelation rate of all materials increased with
increasing temperature although the extent of this influence varied between
materials. The development of elastic recovery in the materials during gelation
accurately fitted asymmetric sigmoids. The correlation coefficient (r) ranged
from 0.982 to 0.999. Statistically significant variations in both the working and
gelation times of the test materials were established. The time of displacement
affected both the rate of development of elasticity and the value of elastic
recovery but this effect was only statistically significant when the displacement
time was increased to 10 s. SIGNIFICANCE: The displacement rheometer may be
suited for use as a standard test method for the determination of the working
time, gelation time and elastic behavior of temporary soft lining materials.
PMID- 9758974
TI - SEM analysis of marginal expansion and gap formation in Class II composite
restorations.
AB - OBJECTIVES: Morphological changes in terms of marginal expansion have been
observed at the dentin-composite interface of resin composite restorations with
the scanning electron microscope (SEM), which could not be described with the
criteria conventionally used for quantitative marginal analysis. The purpose of
the present study was to elucidate the influence of marginal expansion upon
marginal integrity and clarify the cause of these morphological changes. METHODS:
A total of 22 extracted human molars were restored with Class II resin composite
restorations, with and without the use of a dentin bonding agent. The cervical
restoration margin was located below the cemento-enamel-junction (CEJ). The
marginal adaptation at the dentin- and enamel-composite interfaces was evaluated
and measured on replicas using quantitative SEM analysis after different storage
periods. The chemical composition of the marginal expansion was determined
qualitatively by EDX (Energy Dispersive X-Ray) analysis using original tooth
samples. The results obtained from quantitative SEM analysis were statistically
analyzed by applying the Mann-Whitney U-test and the error rates method. RESULTS:
Significantly less marginal expansion occurred at the enamel interface than at
the dentin-composite interface (p < or = 0.01). Within the dentin, less marginal
expansion was observed with the use of a dentin bonding agent than without a
dentin bonding agent (p < or = 0.05). At 1 y, a significant (p < or = 0.05)
decrease in marginal expansion was observed in both groups. EDX analysis revealed
that the chemical composition of the marginal expansion is comparable to the
resin composite, since peaks for silicon, barium and ytterbium could be found at
these sites. SIGNIFICANCE: In Class II resin composite restorations below the
CEJ, partial disruption of the adhesive bond may occur initially when curing the
restoration. Water sorption causes gap reduction by hygroscopic expansion, seen
in the SEM as a volume increase. Thus, the observed morphological changes can be
regarded as an early sign of insufficient adhesion between composite and dentin
at sites where disruption of the bond occurred initially, whether or not a dentin
bonding agent was used.
PMID- 9758975
TI - Fracture studies of selected dental restorative composites.
AB - OBJECTIVES: The purpose of this study was to evaluate the flexure strength,
elastic modulus, and fracture toughness (mode I, mode II, and mixed mode) of
resin and four specially made dental restorative composite materials. METHODS:
Testing was done on prismatic bars in flexure and disk specimens in diametral
compression. Fracture strengths were analyzed using Weibull statistics.
Statistical analysis consisted of a one-way analysis of variance followed by a
Tukey multiple means analysis for each of the materials. In addition, the
fracture strengths were analyzed using Weibull statistics due to the brittle
behavior exhibited by these materials. RESULTS: The experimental results showed
that the addition of fillers resulted in a significant three-fold increase in
flexure modulus and a significant 30-50% increase in fracture toughness from the
resin. As was indicated by the different Weibull modulus values, strength data
obtained from four-point bending were not related with strength data from three
point bending. A straight notch vs. a relatively sharp V-notch gave higher
fracture toughness values. Fracture toughness was dependent on the depth of a
straight notch and was practically independent of the V-notch depth. Mode I and
II fracture toughness in two composites (75Sr and 75Sr10) were carried out on
precracked disk specimens in diametral compression. The results of mode I
toughness were close to those obtained from the flexure testing. The mode II
toughness values were greater than the mode I values by more than 30%. The data
fit an equation of the form KI/KIC + (KII/KIIC)2 = 1(where KI, KII are the mode I
and II stress intensity factors and KIC, KIIC are the respective critical
values). SIGNIFICANCE: Notching technique, testing configuration (three-point vs.
four-point loading), and method of testing (bar vs. disk) have significant effect
on the fracture properties.
PMID- 9758976
TI - In vivo changes in roughness of resin-modified glass ionomer materials.
AB - OBJECTIVES: The clinical changes in roughness of resin-modified glass ionomer
materials is relatively unknown. This study examined the in vivo wear of these
materials using surface roughness as an indicator of wear patterns. METHODS: Ten
patients with four cervical abrasion lesions each were selected. The four
cavities in each patient were restored with Fuji II LC (GC Corp., Japan),
Vitremer (3M Dental, USA), Photac-Fil (ESPE, Germany) and Fuji Cap II (GC Corp.,
Japan). After light-curing, the restorations were polished and left uncoated.
Silicone impressions were made of the surface of each restoration after
polishing, and then at 3 monthly intervals up to 24 mon after restoration
placement. Gold-coated resin replicas were made from the impressions for surface
wear evaluation. Quantitative assessment of wear was performed by measuring
surface roughness with a confocal microscope for topographical reconstruction of
the specimen surface. The effect of material at each time period was analyzed
using the Kruskal-Wallis test with exact non-parametric inference. Rugosity, as
determined by the center line average, was determined by image analysis. SEM
images of the same surfaces provided the qualitative analysis. RESULTS: All
restorations showed a cyclic distribution of rugosity with time as demonstrated
by lowess plots. There were significant differences between materials at 6, 9 and
18 mon. The rugosity curves appeared to converge at 24 mon. SIGNIFICANCE: It was
concluded that the in vivo surface changes in roughness of resin-modified glass
ionomer materials is cyclic in nature over the first 2 y.
PMID- 9758978
TI - Ethics and insurance consultants.
AB - Health care professionals who serve as consultants for insurance companies
provide an essential service in reducing health care costs and ensuring access to
care for increased numbers of people. The role and function of these consultants
is not always appreciated or welcomed by providers, who may view them as
intruders to the doctor-patient relationship and feel that treatment plans are
being second-guessed. Consultants, on the other hand, may be placed in
uncomfortable positions when radiographically visible pathological conditions are
not addressed on a treatment plan. Overlooking such conditions in hopes of not
embarrassing the treating dentist is not an ethical option. When an isolated
omission or error is encountered, it is best for consultants to contact the
treating dentist and advise him or her of the disparity between planned treatment
and observed pathology. Patients, providers, and the profession will benefit
through this collegial exchange of information. When consultants observe
continual omissions or errors, the stakes are much greater and the public's
health must be protected through implementation of the peer-review system.
PMID- 9758977
TI - Sibutramine (Meridia)--dental considerations for a new weight control drug.
PMID- 9758979
TI - Porcelain laminate veneers: Part III.
AB - Porcelain veneers have been an excellent esthetic alternative since introduced to
dentistry. This column and those in the two previous issues have attempted to
outline the important factors for the longest-term result. Following the
guidelines, careful clinical judgment, and a high degree of mechanical skill can
lead to unparalleled esthetic results.
PMID- 9758980
TI - Chest pain as result of temporomandibular disorder (TMD).
AB - Pain referred to the chest, with implications of cardiac distress, is described
in a patient with a history of temporomandibular disorder (TMD). An anatomically
based hypothesis is included to explain the reported chest symptoms. The basis
for nociceptive neuronal interactions between the muscles of the head and neck
has been reported previously. The patient described here suffered from myofascial
pain of the muscles of mastication and the postural muscles of the head and neck.
PMID- 9758981
TI - Stress in elective dental treatment: epinephrine, norepinephrine, the VAS, and
CDAS in four different procedures.
AB - This study focuses on progressive stress during defined, elective dental
treatments, expressed in VAS, CDAS, and catecholamine excretion in urine.
Fourteen male patients had avoided dental treatment for years; all were
classified as ASA risk score I. The different dental sessions were: first visit
after many years; check-up (nonpainful and nontraumatic); drilling and restoring
under local anesthetics; drilling and restoring without local anesthesia; and
extractions. Urine collection was performed directly before and after the
sessions to measure epinephrine and norepinephrine concentrations. Anticipation
stress was registered in the VAS, CDAS, and epinephrine excretion. Progressive
stress was reflected in epinephrine increase, which discriminated between the
different elective dental treatments.
PMID- 9758982
TI - Wound healing and repair: a review of the art and science.
AB - This chronological review of the major biological events that occur secondary to
injury of mucoperiosteal tissue from either simple surgical wounding or trauma
discusses the materials used to repair the compromised tissue surgically.
Suturing techniques and post-surgical wound maintenance also are reviewed. The
physiological stages of wound healing, factors affecting wound healing, and wound
repair techniques are discussed.
PMID- 9758983
TI - Hemangioma-like lesions: diagnosis and management.
AB - The distinctive color that serves as the basis for the appearance of blue lesions
arises from the accumulation of pigmented material, blood, or clear fluid in
abnormal amounts within the oral tissues. Clinical appearance of these lesions
varies and, despite their morphological similarity, their pathogenesis, etiology,
and clinical behavior is different, as are their treatment and prognosis. Because
of the clinical similarity between benign and malignant blue lesions (as
illustrated by the patients described in this report), the need for precise
histologic diagnosis prior to definitive treatment is emphasized.
PMID- 9758984
TI - In vitro evaluation of the Thermafil technique with and without gutta percha
coating.
AB - To determine the sealing ability of the Thermafil technique with and without
gutta percha on the plastic carrier, 40 maxillary incisors were divided into four
treatment groups: (A) Thermafil with gutta percha on the carrier; (B) Thermafil
without gutta percha on the carrier; (C) lateral condensation with standardize
gutta percha; and (D) a single standardized gutta percha cone. Average leakage in
groups A-D were 0.64 mm, 1.32 mm, 0.53 mm, and 0.72 mm, respectively. The only
significant difference was between the Thermafil without gutta percha and the
other three groups (p < 0.05).
PMID- 9758985
TI - The clinical context and utility of tongue biopsies.
AB - Lesions of patients' tongue biopsies are described to determine whether certain
patients had predilections to develop various lesions based on gender or age, and
to determine whether there were significant correlations between the diagnoses,
which could be clinically useful, and the various patients. Surgical pathology
specimens of the tongue were reviewed. Patients' gender, age and diagnoses were
recorded. Most of the 399 patients surveyed were elderly. Patients with epidermal
inclusion cysts or granular cell tumors were significantly younger than others.
Men were younger than women with squamous cell dysplasia and carcinoma. Benign
diagnoses were nearly equally distributed between men and women. Premalignant and
malignant conditions were significantly more common among men than women. Follow
up revealed a moderate degree of risk that a premalignant lesion may later
develop frank malignancy.
PMID- 9758986
TI - Concrescence: a case report.
AB - A rare incident is described involving the extraction of a concrescence at the
point of fusion of two maxillary posterior teeth and its management.
PMID- 9758987
TI - Inflammatory papillary hyperplasia: supraperiosteal excision by the blade-loop
technique.
AB - Inflammatory papillary hyperplasia (IPH) is a benign, irreversible, persistent,
and usually painless lesion of the oral mucosa that is the result of epithelial
proliferation. Many surgical methods of treatment have proven to be not totally
satisfactory in case of surgery, completeness of tissue removal, healing time, or
patient comfort in the postoperative period. A relatively simple and effective
procedure is proposed for the supraperiosteal excision of this lesion from the
palate, using a razor blade cutting element and handle, called the blade-loop
knife, or the Paquette knife handle. The blade-loop technique minimizes trauma
and results in a short and comfortable postoperative period.
PMID- 9758988
TI - A stress-releasing intracoronal attachment for extension base removable partial
dentures.
AB - Intracoronal retainer systems incorporated into splinted abutment restorations
help force distribution. The additional torque introduced by the extension-based
removable partial denture is applied over multiple abutments rather than to
single abutment teeth. A fixed-removable prosthesis is proposed as a solution to
this situation. The Thompson dowel nonlocking semiprecision attachment system is
the intracoronal retainer of choice for distal extension denture bases. It allows
controlled rotation or stress relief of the removable component by minimizing
detrimental transfer of traumatic forces to the abutment teeth. The design and
fabrication of the manufactured version of this retainer system is described.
PMID- 9758989
TI - Removal of surface stains from enamel surfaces with at-home vital bleaching: a
case report.
AB - Stone model casts of a patient's maxillary and mandibular arches were used to
fabricate a clear, soft, vacuum-formed custom mouth guard that was scalloped to
end 1.0 mm supragingivally. The patient was given prophylaxis and oral hygiene
home care instruction, and instructions regarding the placement of an at-home
bleaching gel into the mouth guard and the mouth guard into the mouth. The
patient was asked to wear the mouth guard for two hours daily before bedtime for
one week and to return to the clinic for evaluation. This protocol was followed
for three weeks for each arch. At the end of the three weeks, the stains on the
most affected teeth were reduced dramatically.
PMID- 9758990
TI - Defining prosthodontics.
PMID- 9758991
TI - A definition of prosthetic dentistry.
AB - PURPOSE: A more precise and up-to-date definition of prosthetic dentistry is
warranted. The aim of the present review is to present a new core definition of
the discipline on the basis of a discussion of existing definitions. MATERIALS
AND METHODS: Clinical textbooks in prosthetic dentistry and dental implantology,
as well as medical and dental glossaries were reviewed. RESULTS: Two main
categories of definitions of prosthetic dentistry were identified: first,
definitions that emphasized the technologic aspects of the discipline, i.e., the
fabrication of prostheses; and second, definitions that incorporated some
reference to the objectives or aims of prosthetic treatment, i.e., the
restoration of one or more aspects of oral function. Slightly more than half of
the citations contained such aim-related references, and this aspect tended to be
most pronounced in recent publications. CONCLUSION: The following definition is
ventured: prosthodontics is the discipline of dentistry concerned with the
consequences of congenital absence or acquired loss of oral tissues and with the
methods for and assessment whether more good than harm is done by inserting
artificial devices made from alloplastic materials.
PMID- 9758992
TI - Shade selection for single-unit anterior metal ceramic crowns: a 5-year
retrospective study of 2,500 cases.
AB - PURPOSE: The purpose of this study was to investigate the distribution of shades
selected for metal ceramic crowns provided at a dental teaching hospital.
MATERIALS AND METHODS: Data on the selection of shade for 2,500 metal ceramic
crown units, placed over a 5-year period at the University Dental Hospital of
Manchester, were collected and analyzed. Only those crowns placed adjacent to
minimally restored vital teeth were included in the study. RESULTS: The results
indicate that the most frequently chosen shades were in the mid-range of reddish
brown hue. Furthermore, shades in the reddish-grey range of hue were rarely
chosen. The selection of more than one shade for a crown ("mixed shades") was
generally restricted to the maxillary anterior teeth. CONCLUSION: Knowledge of
the distribution of shades selected for permanently luted metal ceramic crowns
may be a useful adjunct in shade selection, particularly for the inexperienced
operator.
PMID- 9758993
TI - Adjustments and complications of mandibular overdentures retained by four
implants. A comparison between superstructures with and without cantilever
extensions.
AB - PURPOSE: The aims of the study were to evaluate the postinsertion care needed by
patients treated with four implants to retain mandibular overdentures and to
compare two types of superstructures. MATERIALS AND METHODS: The study consisted
of 54 patients who had been treated with conventional maxillary dentures and
mandibular overdentures retained by four implants and a triple-bar superstructure
with cantilever extensions (28 patients) or without cantilever extensions (26
patients). Differences between both groups with regard to age, gender, length,
and diameter of the implants and preoperative mandibular bone height were tested
by means of Student's t and chi-square tests with a probability level of 0.05. No
significant differences were found. Both groups were retrospectively compared on
adjustments and complications. The follow-up period after insertion of the
dentures was 2 years. RESULTS: During the 2-year follow-up, 17 patients of the
cantilever-extension group and 20 patients of the group without cantilever
extensions needed adjustments, and 17 patients of the cantilever group and 12
patients of the group without cantilever extensions had to be treated because of
complications. Significantly more (P < 0.05, chi-square test) superstructure
fractures were present in the cantilever group (14 occasions in 7 patients) than
in the group without cantilever extensions (1 occasion). All superstructure
fractures in the cantilever group involved the cantilever extensions. CONCLUSION:
This study demonstrated a considerable need for postinsertion care, confirming
the necessity of routine follow-up services for patients restored with implant
retained overdentures. Furthermore, the results of this study suggest restriction
of the use of cantilever extensions.
PMID- 9758994
TI - Customized titanium single-implant abutments: 2-year follow-up pilot study.
AB - PURPOSE: The aim of this study was to describe an alternative technique to
fabricate single-implant restorations by using adjustable titanium abutments with
porcelain applied directly to the abutment, and to follow an early group of
patients treated with these crowns. MATERIALS AND METHODS: Seventeen randomly
selected single crowns were consecutively placed in 14 patients and then followed
for 2 years. A protocol of using healing abutments, implant impressions, and
adjustment of the final abutment in the laboratory was used to fabricate the
crowns. RESULTS: The clinical result revealed few clinical problems, and the mean
marginal bone loss was 0.4 mm (standard deviation +/- 0.57 mm) after 1 year in
function. CONCLUSION: The conclusion drawn, based in part on published
literature, was that occurrence of mucosal inflammation and marginal bone loss
was not related to the use of the present protocol.
PMID- 9758995
TI - Differences between traces of adjacent condylar points and their impact on
clinical evaluation of condyle motion.
AB - PURPOSE: Recent research revealed that traces of single posterior reference
points can depend on the location of the monitored point. The aim of this study
was to quantify this dependence and to point out its consequences for clinical
application of condylar path registrations. MATERIALS AND METHODS: In 60
asymptomatic volunteers, mandibular motion was recorded during protrusion,
lateral excursion, and opening-closing of the jaw. Simultaneous trace-patterns of
10 condylar points including the hinge-axis point and the kinematic-axis point
were compared with respect to length, inclination angles, coordination, and
shape. RESULTS: In protrusion, traces of the different condylar points were equal
and independent of the location of the monitored point. Bennett angles depended
on the sagittal position of the reference point and varied by 0.8 degree per 1 mm
change of location. Opening-closing traces differed considerably. Their lengths
varied by up to 9 mm and inclination angles varied by 40 degrees. Opening-closing
patterns also showed irregularities like those observed in temporomandibular
disorders. Irregularities were minor for the hinge-axis point and least for the
kinematic-axis point. CONCLUSION: In tooth-guided movements "condyle motion" is
represented by the traces of any point near the condyle. In opening-closing,
however, the trajectory of a single condylar point will not reliably represent
condylar motion. For articulator adjustment, condylar angles must not be taken
from opening-closing, but only from protrusion. In diagnostic applications, one
has to be aware that irregular traces may not only result from dysfunction, but
may as well be a result of the choice of reference point.
PMID- 9758996
TI - Marginal distortion of thermally incompatible metal ceramic crowns with
overextended margins.
AB - PURPOSE: The present study tested the hypothesis that metal ceramic crowns with a
varying axial height are more susceptible to marginal distortion during
mechanical and thermal processing treatments than crowns with a uniform axial
height. MATERIALS AND METHODS: Copings of Pd-Cu-Ga alloy with buccal margin
extensions of 0, 1.5, and 3.0 mm were prepared. Oxidized copings were veneered
with experimental opaque porcelain with a mean thermal contraction coefficient
(25 degrees C to 500 degrees C) that was either 2.1 ppm/degree C below (delta
alpha = +2.1 ppm/degree C) or 0.1 ppm/degree C above (delta alpha = -0.1
ppm/degree C) that of the alloy. Nine groups of six specimens each were prepared
for analysis. Eighteen copings from these 54 specimens were used as porcelain
free controls. All specimens were subjected to a 10-step procedure including
grinding, oxidation, firing of four opaque porcelain layers (O1: 0.15 mm; O2:
0.15 mm; O3: 0.5 mm; O4: 0.5 mm), glazing, abrasive blasting for 15 seconds,
removal of ceramic by dissolution in hydrogen fluoride, and a postannealing
treatment. The control specimens were also subjected to this procedure with the
exception of the firing of four layers of porcelain, which were not applied.
Marginal gap width was determined using a measuring microscope at a magnification
of 30x. RESULTS: Analysis of variance revealed a significant difference in mean
gap width as a function of axial length. The largest gap change was associated
with a 3.0-mm buccal extension and the negative mismatch condition (delta alpha <
0). CONCLUSION: Marginal distortion of crowns decreases as the axial length
becomes more uniform. Analysis of crown distortion based on differences in the
mean contraction coefficients of metal and porcelain alone is not recommended
because it ignores the effects of metal grinding, metal sandblasting, and
transient stress.
PMID- 9758997
TI - Effects of preparation and luting system on all-ceramic computer-generated
crowns.
AB - PURPOSE: Computer-aided design/computer-integrated machining (CAD/CIM) allows
defect-oriented custom-shaping of the inside surfaces of all-ceramic crowns. The
purpose of this study was to examine the effect of inside crown form on fracture
strength of cemented and bonded crowns. MATERIALS AND METHODS: Four preparation
types were used: (1) "classic" with a butt shoulder of 1.2 mm, abutment height of
4 mm, and 6-degree convergence, (2) like type 1 with mesio-occlusodistal cavity,
(3) like type 1 with height reduced by 50%, and (4) like type 1 with abutment
reduced by 100% plus a pulp chamber cavity. Crowns were CAD designed on
preparations 1 to 4 using identical outside morphology. Machined crowns were
placed on abutments (a) without any media as controls (n = 15), (b) cemented (n =
15), and (c) bonded (n = 15), and were loaded until fracture. RESULTS: Zinc
phosphate-cemented crowns (1b, 2b, 3b, and 4b) showed significant (P < 0.001)
increase of fracture load values compared to uncemented control crowns (1a, 2a,
3a, 4a). Fracture load values of bonded crowns (1c, 2c, 3c) were significantly (P
< 0.001) higher than those for cemented crowns. Bonded crowns with thick occlusal
dimensions (3c and 4c) showed the highest fracture load values. CONCLUSION:
Bonded all-ceramic CAD/CIM crowns with defect-oriented inside morphology and
increased occlusal dimensions showed high fracture load values.
PMID- 9758998
TI - Effect of water storage on the flexural properties of E-glass and silica fiber
acrylic resin composite.
AB - PURPOSE: The aim of this study was to determine the effect of water on the
flexural properties of fiber-reinforced denture base polymers. MATERIALS AND
METHODS: Continuous woven silanized electrical glass, or E-glass, fibers and
woven silica fibers were used to reinforce heat-cured and autopolymerized denture
base polymers. Fibers were oriented at a 45-degree angle to the long axis of the
test specimens. Control specimens were unreinforced. Dry test specimens and those
stored in water for up to 48 weeks were tested with a three-point loading
apparatus. The surfaces of the fibers of the test specimens stored dry or 48
weeks in water were analyzed with a scanning electron microscope to evaluate the
degree of adhesion between fibers and polymer matrix. RESULTS: The ultimate
transverse strength of unreinforced and reinforced denture base polymers
decreased during 48 weeks' storage in water (P < 0.05, one-way analysis of
variance, n = 5), and most of this reduction occurred during the first 4 weeks of
storage in water. The flexural modulus of the unreinforced test specimens
decreased significantly (P < 0.001), whereas there was less, if any, change in
the flexural modulus of the fiber-reinforced test specimens. Scanning electron
microscopic examination revealed no differences in adhesion of E-glass fibers to
the polymer matrix when the specimens stored in water were compared with those
stored by. Reduced adhesion between the silica fibers and matrix was observed
after 48 weeks' storage in water. CONCLUSION: The results of this study suggest
that the ultimate transverse strength of the E-glass fiber-reinforced test
specimens decreased 14% and that of the silica fiber-reinforced test specimens
decreased 36% after 48 weeks of storage in water.
PMID- 9758999
TI - Five-year prospective study of prosthodontic and surgical single-tooth implant
treatment in general practices and at a specialist clinic.
AB - PURPOSE: The aim of this 5-year prospective study was to compare the results of
single-tooth implant treatments planned and performed at four general
practitioners' offices with the results from a specialist clinic. MATERIALS AND
METHODS: The group comprised 38 patients. Nineteen patients, with 19
implants/crowns, were planned and treated by four general practitioners, and the
outcome was compared to a matched group of patients from a specialist clinic.
RESULTS: Three patients did not complete the study. None of the implants failed;
one crown failed. This was a very positive result, as the single failure, a crown
at the specialist clinic, was caused by an extraordinary trauma and was not
related to a common cause such as bite forces or fatigue. No significant
differences were observed between the groups when the radiographic findings were
compared. Some minor differences, for bleeding and the position of the mucosal
level around implants and adjacent teeth, were observed between the two groups.
CONCLUSION: The small discrepancies that were observed between treatment
performed by the four general practitioners at their own offices and treatment
performed at the specialist clinic were not regarded to be of any clinical
importance. This indicates that complete single-tooth implant treatment may be
performed for many patients by general practitioners who have received adequate
training, allowing the possibility of referring complicated treatments to
specialists and other treatments to general practitioners.
PMID- 9759001
TI - Make teeth--and money!
PMID- 9759000
TI - Use of wide-diameter and standard-diameter implants to replace single molars: two
case presentations.
AB - PURPOSE: The ultimate goal in modern esthetic dentistry is the restoration of
lost hard and soft tissues by imitating nature as closely as possible. With the
increasing esthetic awareness of patients, surgical and technical developments,
and dentists' enhanced skills and knowledge, optimal function and esthetics are
achievable even with implant-supported restorations in molar regions. Anatomic
and morphologic factors and poor bone quantity and quality might reduce success
rates of dental implants in the posterior jaw. Today, there are two options to
replace a single missing molar by an implant-supported crown: the single wide
diameter implant or two standard-diameter implants. These two approaches are
described and their advantages and disadvantages discussed in two exemplary
clinical cases. MATERIALS AND METHODS: In one case, the edentulous ridge in the
area of the mandibular right first molar (FDI tooth 46) provided sufficient
mesiodistal space to restore tooth 46 with a porcelain-fused-to-metal crown on
two standard-diameter implants, placed in a root-analog manner. In the other
case, the manibular first molars (FDI teeth 36 and 46) were replaced by porcelain
fused-to-metal crowns on wide-diameter implants. RESULTS: It can be concluded
that both options to replace a single molar provide more surface area and better
biomechanical properties than one standard implant. CONCLUSION: Long-term data
are needed before these treatment modalities can be recommended for the private
practitioner.
PMID- 9759002
TI - A new twist on single screw-retained implant restorations.
AB - Several laboratories have stopped accepting implant cases because of the
technical demands and the additional labor time required to process them. This
article will discuss the IMPAC PDQ abutment (Vident, Brea CA). This abutment
offers technicians a simple, reliable method for producing a strong, high quality
implant substructure ready for porcelain application in a matter of minutes.
PMID- 9759003
TI - Putting their artistic skills to use: Georgia high school students learn a craft-
and make money at the same time.
PMID- 9759005
TI - Why aren't dental technicians paid more?
PMID- 9759004
TI - Training our trainers: dental laboratory management's challenge for the next
decade.
AB - Training has been shown to be an important factor in the growth of successful
dental laboratories. Many technicians have received extensive laboratory and
managerial training in the midst of technician shortages, more sophisticated
techniques and products. What can we do to insure the manpower needs of the
dental laboratory industry will be met in the future? A potential answer is
learning and developing the skills to train our supervisors who train our
trainees. We must remember, however, the focus of effective training is not the
product (books, tapes, slides, etc), but the processes we bring to the training
arena. Understanding and implementing the S.M.A.R.T. system for training goals,
having a thorough and workable knowledge of adult learning theory, spaced
repetition, and the seven W's will assure the laboratory owner that he will be
able to effectively address the manpower and training needs of a profession
moving quickly in the new millennium.
PMID- 9759006
TI - To be, or not to be, a technician.
PMID- 9759007
TI - Self respect.
PMID- 9759008
TI - Direct/indirect band placement.
AB - This article describes orthodontic band placement in alginate impressions. The
fitting of orthodontic bands at the chair and the indirect transfer of the bands
to the impression influences the fit and function of the preventive or
interceptive orthodontic appliance being fabricated. Some of the problems
associated with the transfer of bands to impressions will be presented. In
addition, a discussion of methods to eliminate these problems is included.
PMID- 9759009
TI - A method of making decalcifications in the porcelain build up.
AB - This article describes a method for making white decalcifications or modeling
characterizations that attempt to duplicate natural teeth. Common techniques
often use white stain applied to the wet porcelain or painted on as surface
stain. A simplified and reproducible technique is provided that allows this
characterization to be completed as part of the porcelain build up. A mixture of
three powders causes an improved appearance that can lighten the incisal and
occlusal surfaces to help create greater contrast with the body porcelain for a
more natural result.
PMID- 9759010
TI - Discipline: the most misunderstood word for laboratory management and its
employees.
PMID- 9759011
TI - 'Spiders' offer easy access to index-liked performance.
PMID- 9759012
TI - A conversation with the NBC chairman: a way I thought I could contribute.
PMID- 9759013
TI - Case 3: Replantation of vertically fractured tooth.
PMID- 9759014
TI - Effects of dentin bonding agents on macrophage mitochondrial activity.
AB - Dentin bonding agents (DBA) have been considered for use as root-end fillings.
Previous studies have documented the release of DBA components in vivo and in
vitro, but the biological implications are not clear. The macrophage is important
in wound healing, and likely to be important in any inflammatory response.
Therefore, this study determined the concentrations of the components of DBAs
that suppress the mitochondrial activity of human macrophages in vitro. THP-1
macrophages were cultured in the presence of four DBA components (2-hydroxyethyl
methacrylate (HEMA), 4-methacryloxyethyl trimellitate anhydride (4-META),
bisphenol-glycidylmethacrylate (Bis-GMA), and urethane dimethacrylate (UDMA)) at
various concentrations and for varying durations. Residual effects were also
measured after the resins were removed. Controls received only the vehicle
solution, ethanol or water. THP-1 mitochondrial activity was estimated using the
MTT assay, and the 50% toxicity concentrations (TC50) were determined
graphically. Resin components suppressed the mitochondrial activity of
macrophages at different concentrations (TC50 values for HEMA (10,000 mumol/L), 4
META (3,800 mumol/L), Bis-GMA (130 mumol/L), and UDMA (110 mumol/L) at 24 h, and
the effect was time-dependent. Residual effects were observed for all resins.
PMID- 9759015
TI - Cytotoxic effect of endodontic bacteria on periapical fibroblasts.
AB - This study was conducted to investigate the effects of sonicated bacterial
extracts (SBEs) from anaerobic Gram-negative bacteria on periapical fibroblast
obtained from the apical portion of human periodontal ligaments. Porphyromonas
endodontalis, Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium
nucleatum were chosen from among the endodontic bacteria isolated from root
canals having a periapical lesion and compared in terms of their cytotoxicity.
The purpose of this study was to examine which bacteria are involved in the
development of periapical inflammation. The anaerobes were cultured under strict
anaerobic conditions, and the bacterial cells were then harvested by
centrifugation after incubation. The concentrated cell suspensions were sonicated
and subsequently centrifuged. An SBE was made of each of the filtered
supernatants. Each SBE was added to cultures of periapical fibroblasts. The cell
growth and proliferation were measured by the MTT method after 3, 5, and 7 days.
The SBEs from P. endodontalis, P. gingivalis, and F. nucleatum inhibited the
growth of the fibroblasts, whereas the SBE from P. intermedia did not inhibit it.
The SBEs from P. gingivalis and F. nucleatum inhibited the fibroblast growth more
strongly than did the P. endodontalis, P. gingivalis, and F. nucleatum may
participate in the development of periapical lesions.
PMID- 9759016
TI - A new muffle model system to study root canal morphology and instrumentation
techniques.
AB - A new muffle model system is presented using the principle of internal indexing.
The system is composed of a metal stand, four pins, and a single Teflon mold that
is used for the investment of all teeth. This system is very precise,
reproducible, and versatile. The sectioned specimens can easily be stored
assembled, as opposed to previous systems that rely on external indexing.
PMID- 9759018
TI - Efficacy of Er:YAG laser irradiation in removing debris and smear layer on root
canal walls.
AB - The purpose of this study was to evaluate the efficacy of Er:YAG laser
irradiation in removing debris and smear layer from prepared root canal walls.
Thirty-six human extracted mandibular incisors teeth were divided into three
groups. Group 1 (G1) was control specimens that were not lased. The teeth of
group 2 (G2) and group 3 (G3) were irradiated by Er:YAG laser at different watt
powers of 1 W and 2 W. The teeth were bisected and prepared for study in
stereoscopic light microscope and SEM. Control specimens showed an amount of
debris and heavy smear layer obscuring the dentinal tubules at all levels in the
canals. The root canal walls irradiated by Er:YAG laser were free of debris, with
an evaporated smear layer and open dentinal tubules. Statistical analyses showed
significant differences (p < 0.01) in cleanliness smear layer between G1 and G2,
and G1 and G3. However, there was no statistically significant difference between
G2 and G3 in the cleanliness of the middle and apical one-third of the root
canals. These results show Er:YAG laser is effective in removing debris and smear
layer from root canal walls.
PMID- 9759017
TI - Cellular response to Mineral Trioxide Aggregate.
AB - This investigation studied the cytomorphology of osteoblasts in the presence of
Mineral Trioxide Aggregate (MTA) and examined cytokine production. MTA and
Intermediate Restorative Material (IRM) were prepared and placed in separate
Petri dishes. Osteoblasts (cell-line MG-63), grown to confluence in Hams
F12/Dulbecco's modified Eagle's medium, were seeded into the dishes, which were
incubated for 1 to 7 days. The specimens were viewed by scanning electron
microscopy. For cytokine evaluation, cells were grown either alone or in other
dishes containing the test materials for 1 to 144 h. Media were removed for ELISA
analysis of interleukin (IL)-1 alpha, IL-1 beta, IL-6, and macrophage colony
stimulating factor. Scanning electron microscopy revealed healthy cells in
contact with MTA at 1 and 3 days; in contrast, cells in the presence of IRM
appeared rounded. The ELISA assays revealed raised levels of all ILs at all
periods when cells were grown in the presence of MTA; in contrast, cells grown
alone or with IRM produced undetectable amounts. The macrophage colony
stimulating factor was produced by cells irrespective of the group. It seems that
MTA offers a biologically active substrate for bone cells and stimulates IL
production.
PMID- 9759020
TI - Long-term seal provided by some root-end filling materials.
AB - A tight and long-lasting seal of root-end fillings is of prime clinical
importance. A hundred standard bovine root sections, each 3 mm high and with a
central pulp lumen of 2.6 mm in diameter, were filled with five commonly used or
potential root-end filling materials. At 24 h, or at 3, 6, or 12 months after
filling, leakage along these filling materials was determined under a low
headspace pressure of 10 kPa (0.1 atm) using a fluid transport model. During the
first 3 months, the percentage of gross leakage (> 20 microliters day-1)
increased noticeably for Tytin amalgam (from 20 to 100%) and Super-EBA (from 0 to
55%), whereas it decreased noticeably for mineral trioxide aggregate (MTA; from
55% to 0%). Thereafter, the increased leakage of amalgam and Super-EBA decreased
with time, whereas the improved seal of MTA was maintained until the end of the
experiment. At 3-, 6-, and 12-month time intervals, both glass ionomer cements
(Fuji II and Hi Dense) and MTA showed less leakage than the conventional amalgam
and Super-Eba, of which amalgam leaked more.
PMID- 9759021
TI - Rapid sterilization of gutta-percha cones with glutaraldehyde.
AB - Five commercially available liquid glutaraldehyde preparations (Glutaron II,
Cidex 28, Glutalabor, Banicide, and Anti-G-Plus) were compared for effectiveness
in sterilizing gutta-percha cones artificially contaminated with Bacillus
subtilis ATCC 6633 spores. Sporicidal activity differed for the various brands of
cones, but after 15 min all glutaraldehyde solutions were effective in
eliminating the spores. However, three solutions (Cidex 28, Banicide, and Anti-G
Plus) showed sporicidal activity within a shorter time (10 min). All
glutaraldehyde solutions tested may be used in endodontic practice for rapid
decontamination of gutta-percha cones, thus contributing to the maintenance of
the aseptic chain, an essential factor for successful root canal treatment.
PMID- 9759019
TI - Subjective sensation and objective neural discharges recorded from clinically
nonvital and intact teeth.
AB - The aim of this study was to compare subjective sensation with objective neural
discharges recorded by microneurography. We examined human teeth that did not
respond to pulp vitality testing, but that responded to cavity preparation for
endodontic treatment (pathophysiological). Intact teeth and endodontically
obturated teeth were used as controls. Pulpal blood flow in the clinical crown
and histological examination were also used. Most teeth, both in normal and
pathophysiological conditions, did not respond to all pulp vitality tests. Even
when teeth in the pathophysiological group showed spike discharges evoked by pulp
vitality tests or from spontaneous activity no sensation was elicited. These
results confirmed the usefulness of microneurography for research on pulpal
sensation and the significance of summation in the perception of sensation in
chronically inflamed tooth pulp.
PMID- 9759022
TI - Effects of eugenol and noneugenol endodontic sealer cements on post retention.
AB - Resin cements are sometimes recommended to enhance the retention of posts in
endodontically treated teeth. Many sealer cements used in endodontics contain
eugenol, however, which has been shown to inhibit the polymerization of resins.
The purpose of this study was to evaluate the effects of a eugenol and a
noneugenol sealer cement on the retention of posts. Sixty extracted canines were
divided equally into four groups. Each tooth received conventional endodontic
therapy and was prepared to receive a post. Two sealer cements were used in
obturation: one contained eugenol and one was eugenol-free. The posts were
cemented with either zinc phosphate cement or resin cement. Each combination of
sealer and post cement was tested for retention on an Instron testing machine.
The type of sealer used had no effect on post retention with either cement. Post
retention was significantly greater with the zinc phosphate cement than the resin
cement.
PMID- 9759024
TI - Resistance to fracture of three all-ceramic systems.
AB - All-ceramic restorations have become an attractive alternative to porcelain-fused
to-metal crowns, but their strength is still an important issue. The purpose of
this study was to compare the in vitro fracture resistance of three all-ceramic
systems: IPS Empress, In-Ceram, and Procera AllCeram. Thirty dies were replicated
from a master die using high filler resin with a modulus of elasticity similar to
dentin. Ten cores each of In-Ceram and Procera were fabricated to a thickness of
0.5 mm. The remaining porcelain was applied using a sculpting device to produce a
crown with a final thickness of 1.0 mm axially and 2.5 mm occlusally. Ten IPS
Empress crowns were mixed to the same dimensions and were pressed by the
manufacturer. The internal surfaces of all the crowns were etched and silanated
prior to cementation with a resin cement (Panavia 21). The cemented samples were
loaded in an Instron machine until fracture. The mean fracture loads were: IPS
Empress, 222.45 (+/- 49) kg; In-Ceram, 218.8 (+/- 36) kg; Procera AllCeram,
194.20 (+/- 37) kg. Tukey's test showed no statistically significant differences
among the three all-ceramic systems at p < .05.
PMID- 9759023
TI - Polyethylene ribbon and fixed orthodontic retention and porcelain veneers:
solving an esthetic dilemma.
AB - The patient, a 58-year-old woman, had started orthodontic treatment to correct
spacing between the maxillary anterior teeth 6 year prior to presentation with a
chief complaint of tooth discoloration and spacing. The treatment had consisted
of the use of a removable appliance to retract the maxillary anterior teeth. The
patient continued to wear the appliance sporadically. When she presented, the
maxillary incisors were in primary occlusal trauma with Grade 2 mobility. The
patient discontinued wearing the appliance. The periodontal condition was
addressed with initial therapy. As part of the treatment plan to stabilize the
maxillary anterior teeth and provide the patient with an esthetic result, it was
decided to do a limited occlusal adjustment of the maxillary anterior teeth to
control fremitus, and to place a fixed, composite resin, polyethylene ribbon
reinforced splint, using a facial approach. The esthetic restoration of these
teeth was accomplished with bonded porcelain veneers.
PMID- 9759025
TI - Porcelain veneers: adjunct or alternative to orthodontic therapy.
AB - Elective esthetic dentistry defines "art form" within the field of dentistry.
Most frequently, a clinical team of skilled professionals is required to satisfy
the discriminating patient who presents with an esthetic-driven agenda. This
article describes a patient who has rejected orthodontic therapy but continues to
seek esthetic alternatives. Porcelain laminate veneers were an appropriate
alternative in this case. The second case demonstrates the synergy of combined
therapies that were explained to the patient and strategized from the onset to
facilitate a result not obtainable by a singular approach. One should not infer
that porcelain laminate veneers are an automatic substitute for orthodontic
therapy. There may be instances when this is required; however, in most
instances, conservative esthetic therapies, such as porcelain laminate veneers,
supplement orthodontic therapy to create a final result not possible with either
singular approach.
PMID- 9759026
TI - Esthetic restoration of endodontically treated teeth: factors that affect
prognosis.
AB - Restoration of endodontically treated teeth involves a complex system of
components and component interfaces designed to resist force. Dental materials,
forces on teeth, clinical circumstances, and restorative design determine
restoration success. A new classification evaluates number of canals, amount of
remaining tooth surface, chamber space, canal quality, and canal orientation.
PMID- 9759027
TI - Procedures for enamel and dentin conditioning: a comparison of conventional and
innovative methods.
AB - Composite materials have become an integral part of the wide range of filling
materials currently available. Conditioning is necessary to achieve adequate
bonding of the composite material to enamel and dentin. Normally, this is done by
applying acid preparations to the dental surfaces. These acids have an etching
effect that causes surface roughening. The increasing application of lasers in
dentistry has introduced another possibility. Laser irradiation can cause
roughening of enamel and dentin surfaces. Another interesting alternative is the
so-called kinetic cavity preparation technique. This method also results in
distinct surface roughening. The purpose of the present study, was to compare the
described methods. Tensile bond strength tests and shear bond tests were carried
out to examine the adhesion of a composite material to surfaces treated with
these methods. Laser irradiation with certain devices and the air-abrasive
technique yielded results similar to those with acid etching.
PMID- 9759028
TI - "The view" and the canine connection: an atlas of mandibular anterior tooth
esthetics.
AB - Restoring splinted mandibular incisors and canines with full crown restorations
has always presented a challenge in creating an esthetic illusion of reality of
normal individual teeth. This treatise is designed to present the rules for
mandibular anterior esthetics that have been distilled from almost 4 decades of
clinical practice of restoring dentitions that have been severely compromised by
the deformities of disease or accident. The resultant formula systematically
creates the desired results with a high degree of predictability.
PMID- 9759029
TI - Soft tissue modeling for the esthetic single-tooth implant restoration.
AB - The ability of the restorative dentist to understand and control the relation of
the implant to its associated gingival tissues is extremely important in
achieving the maximum esthetic result in the final restoration. The position of
the gingival margin following stage-two surgery represents collapse of the
gingival tissues until it finds support by the component against which it comes
to rest. This component may be a healing abutment, final abutment, or provisional
restoration, if placed at the same time of implant exposure. Generally, it will
be a healing abutment. There is complex relation between implant position,
gingival management at stage-one and stage-two surgery, the position of the
gingival margin over the buccal surface of the implant compared to the adjacent
natural teeth, component selection, and lip line esthetics. The therapist who
understands these relations will know how to mold the gingival tissue around
implants to maximize the esthetic result. This article focuses on these relations
and the technique of tissue modeling with subgingival contours to create a
restoration with the illusion of reality.
PMID- 9759030
TI - Use of prosthesis-generated computed tomographic information for diagnostic and
surgical treatment planning.
AB - Diagnosis, treatment planning, and prediction of a final implant-supported
prosthetic outcome require precise noninvasive presurgical information. By
combining the use of a clinically verified barium-coated template and interactive
computed tomography (SIM/Plant, Columbia Scientific, Inc., Columbia, Maryland),
the implant team can determine and address the relevant issues affecting
treatment outcomes. Those issues include: implant-prosthesis incompatibility,
recognition of anatomic limitations and anomalies, the need for presurgical bone
augmentation, implant diameter and distribution, abutment type and angle, bone
density, soft tissue augmentation requirements, accurate fee determination, and
medicolegal protection. The data collection methodology and format for the Mecall
and Rosenfeld prosthesis prediction analysis are discussed as part of case
presentation.
PMID- 9759031
TI - Fifty years of interdisciplinary site development: lessons and guidelines from
periodontal prosthesis.
AB - Just as "osseointegration" became synonymous with successful restoration of
function in the fully edentulous patient during the 1980s, the term "implant site
development" has become intricately associated in the 1990s with the techniques
used to achieve esthetic results with implants in the partially edentulous
patient. This article explores the roots of the concept of site development
within the philosophy and principles of periodontal prosthesis. In addition, the
myriad of techniques that are presently collectively referred to as site
development are systematically classified into a sequential four-tiered approach
that optimizes their efficient application as well as overall success.
PMID- 9759032
TI - Biologic width and its relation to periodontal biotypes.
AB - Although average measurements of the biologic zone do not necessarily reflect any
one clinical situation, they do establish a basis upon which clinical decisions
can be made. Clinical impressions, human autopsy material, and animal studies
support the concept of a biologic width. Impingement on the attachment in a
susceptible host has shown adverse reactions, including gingival inflammation and
alveolar bone loss. The concept is clinically important in determining the extent
of osseous surgery necessary in the exposure of sound tooth structure. If the
implant-abutment interface is considered to be similar to a subgingival crown
margin, its importance in relation to peri-implant inflammatory disease is
readily apparent. In the presence of inflammation, it is likely that epithelial
migration would occur to a level apical to that source. Clinical observations
indicate that, once the biologic attachment is invaded around the implant, the
gingival reactions are similar to those found around natural teeth, whether the
tissue is of the thick flat or thin scalloped type.
PMID- 9759033
TI - Sinus floor elevation with osteotomes.
AB - This article describes a new methodology for augmentation of the bone at the
sinus floor that is less invasive than previous techniques. This procedure is
called the osteotome technique. Two different applications of the osteotome
technique are described. First an implant site is created in a location that
previously had inadequate bone for immediate fixation of an implant. In a second
surgical step additional augmentation of the bone is carried out when the implant
is inserted. This case report provides details, from the original ridge defect
with 1 to 2mm of bone under the low sinus to the final esthetic crown restoration
on a 5 x 13-mm external-hex screw implant that is supported by newly generated
bone.
PMID- 9759034
TI - Implants as anchorage in orthodontics: a clinical case report.
AB - Often, in dental reconstruction, orthodontics is required for either functional
or aesthetic reasons. Frequently, the critical anchorage necessary to move the
teeth may be lacking. This article documents how critically located implants can
be used as anchorage during orthodontic treatment and can become definitive
support for the final reconstruction. Osseointegrated implants in this manner
achieved a more ideal and acceptable result for this patient.
PMID- 9759036
TI - The complete mandibular subperiosteal implant: an overview of its evolution.
PMID- 9759035
TI - Effects of chemotherapy on osseointegration of implants: a case report.
AB - A patient underwent mandibular resection for high-grade osteosarcoma with
immediate reconstruction with a microvascular fibula free bone graft and
simultaneous placement of osseointegrated implants. Following initial healing,
she underwent six cycles of chemotherapy and had further revision surgery prior
to implant exposure and construction of a prosthesis. The chemotherapy appears to
have had no deleterious effects on implant osseointegration or survival.
PMID- 9759037
TI - Tripodal mandibular subperiosteal implant: basic sciences, operational
procedures, and clinical data.
AB - A tripodal mandibular subperiosteal dental implant is a three piece cast metal
framework that fits on the residual ridge beneath the periosteum and provides
support for a dental prosthesis by means of posts or other mechanisms protruding
through the oral mucosa. This implant is indicated in patients with advanced
atrophy of the mandible where the unstable alveolar bone has completely
disappeared, leaving in place the more stable basal bone with specific anatomical
contours. The authors present their experience of 317 cases carried out in three
different centers related to this implant modality and underline the importance
of the basic anatomic, physiologic, and medical knowledge required to optimize
the results.
PMID- 9759039
TI - Implant dentistry today.
PMID- 9759038
TI - Oral microbiota and implant type membranes.
AB - Candida albicans (Ca), Staphylococcus aureus (Sa), Streptococcus sanguis (Ss),
Actinomyces naeslundii (An), Actinomyces odontolyticus (Ao), Porphyromona spp (P
spp), Candida glabrata (Cg), Candida krusei (Ck), and Rhodotorula spp (R spp)
were tested with equal pieces of biodegradable membranes. Membranes pretreated
with saliva or clorhexidine and nontreated control membranes were tested in three
different culture media containing 0.1 mL homologous suspension for each strain
under study. Incubation was performed at 37 degrees C for 48 hours for aerobiosis
and for five days for anaerobiosis. Macroscopy and microscopy were carried out.
Membranes were removed, washed, and resuspended. Samples were sonicated, and the
supernatant was disseminated on brain heart infusion broth or blood agar.
Incubation was repeated, colony-forming unit counts were performed, and
statistical analysis was carried out using analysis of variance transforming
results to Log10 (x + 1), the highest interaction level was used to calculate
standard error. Orthogonal contrast was used to compare the different
microorganisms under study. Highest adhesion was found with Ca, Cg, Ck, Sa, and
Ss. A sufficient quantity of Actinomyces could not be recovered from the
membranes. Results with P spp were poor, confirming lower gram-negative adhesion.
Replicate flasks with Ss and Ca were cultivated. Membranes were removed after
washing and subjected to scanning electron microscopy, as were untreated control
pieces. A cavelike surface was observed. Streptococcus sanguis adhering to the
membranes showed extracellular projections. Candida and gram-positive cocci
showed great recovery capacity.
PMID- 9759040
TI - Orofacial pain uptake. 1.
PMID- 9759041
TI - Volunteerism that spans the globe.
PMID- 9759042
TI - An evaluation of differences and similarities observed in fixture failure of five
distinct implant systems.
AB - While the long-term success of osseointegrated implants has been demonstrated in
the dental literature, implant failure does occur as a result of various factors.
The purpose of this investigation was to identify clinical and/or microbiological
differences associated with failure in five implant systems. At the conclusion of
this 7.5-year investigation, 67 of 958 implants were determined to have failed.
An overall failure rate of 7.0% was evident in this study, which, depending on
the particular system, ranged from 4.7% to 15.2%.
PMID- 9759043
TI - The extracted tooth pontic--provisional replacement during bone graft and implant
healing.
AB - When tooth extraction is required, a provisional restoration may be utilized as
an interim prosthesis during bone graft and implant healing. The selection of
provisional replacement of the anterior teeth following extraction may have a
direct influence on the success of the definitive tooth replacement. This article
describes a technique for using the extracted tooth or a denture tooth as an
interim prosthesis during bone graft and implant healing. This method of
provisionalization offers several advantages, including no adjacent tooth
preparation, natural appearance, and retention of the papillae.
PMID- 9759044
TI - Controlled restorative treatment of compromised anterior dentition.
PMID- 9759045
TI - Use of acellular dermal matrix for increasing keratinized tissue around teeth and
implants.
PMID- 9759046
TI - The use of transitional implants for immediate fixed temporary prostheses in
cases of implant restorations.
AB - While the original Branemark implant protocol has continued to evolve, the
avoidance of implant loading during osseointegration remains a prerequisite with
all implant systems. Immediately loaded transitional implants have recently been
developed to support the fabrication of a fixed provisional prosthesis that
provides implant patients with improved aesthetics and function during the
osseointegration period. In this manner, osseointegration can occur free from
prosthetic and transmucosal loads. This article describes the use of transitional
implants and presents a classification of three different case types.
PMID- 9759047
TI - Soft tissue injuries received during motor vehicle accidents.
PMID- 9759048
TI - Cementable mechanics and implant dentistry.
PMID- 9759049
TI - Radiographic/surgical template incorporating metal telescopic tubes for accurate
implant placement.
AB - The dental literature is replete with information on various implant surgical
template designs and imaging techniques for presurgical assessment of dental
implant sites. Seldom are these two aspects combined in a practical and effective
manner to fabricate a guide for precise implant placement. Unless detailed, three
dimensional images of the underlying bone are obtained, the use of a template is
ineffective. This article describes a radiographic/surgical template that
utilizes a series of telescoping metal tubes as radiographic markers and as
implant drill guides.
PMID- 9759050
TI - Fifty years on: does the NHS still need dentistry.
PMID- 9759051
TI - A study of young people's perceptions of their orthodontic need and their
experience of orthodontic services.
AB - A study investigating young people's perceptions of their orthodontic needs,
demands and their experience of orthodontic services was conducted in Walsall and
Dudley health districts, using a self-completed questionnaire. The subjects were
4812 individuals in year 10 of education (average age 15.0 years). Overall, the
level of malocclusion perceived by the young people was similar to that
identified by dentists in the 1993 national survey of children's dental health.
The level of reported malocclusion by boys and girls, white and non-white
students and students from the two districts was the same; however fewer students
from the less prosperous neighborhoods reported having straight teeth, and more
non-white students with irregularities wanted to have straight teeth. Although
many young people reported having a malocclusion, the majority were not concerned
about it. The study revealed significant differences in experience of treatment.
Boys, non-white students and students from less prosperous areas were less likely
to report having active orthodontic treatment. Access to specialist services was
lower for the non-white students and students from less prosperous areas. A
higher proportion of students treated with fixed appliances reported straight
teeth after treatment than those treated by extractions alone or by removable
appliance therapy.
PMID- 9759052
TI - A clinical audit project. Record-keeping of patient status and monitoring.
AB - This paper describes an audit of record-keeping of key information that needs to
be readily available to assist in the delivery of a high standard of patient
care. It resulted in the development of adhesive forms to be affixed to the front
of the patient's record card. The use of these forms is described and
illustrated.
PMID- 9759053
TI - MGDS case presentation: hypodontia with retained deciduous teeth.
AB - This case, which was presented as a log diary for the 1997 Diploma of Membership
in General Dental Surgery (MGDS) examination, describes the examination,
treatment planning, and subsequent treatment of a patient displaying mild
hypodontia with retained deciduous teeth and lateral excursions guided by group
function. It incorporates preventive treatment and management of early
interproximal caries, prerestorative orthodontics, reorganisation to a canine
guided occlusion using conventional and adhesive cast restorations, and
management of an occasional clenching habit.
PMID- 9759054
TI - The MGDS examination: a systematic approach. 3. Part II of the examination:
diagnosis, treatment planning, execution of treatment, maintenance and appraisal,
writing-up log diaries.
AB - This paper is the third in a series of four which present a systematic approach
to colleagues who are preparing for and sitting the examination for the Diploma
of Membership in General Dental Surgery (MGDS) of The Royal College of Surgeons
of England. Although some details may differ, the general principles set out in
the four papers apply equally to the MGDS examinations of the other Royal
Surgical Colleges.
PMID- 9759055
TI - A survey of the views of vocational dental practitioners on continuing
professional education.
AB - The Faculty of General Dental Practitioners (UK) has been leading the debate on a
career pathway in general dental practice for a number of years. Little work has
been done to establish the views of young dentists on the ideas behind a career
pathway and on vocational training. This paper describes a questionnaire survey
of 77 recently qualified dentists in the Thames region. The results show that
there is great satisfaction with vocational training (76.4%) among the
respondents even if it were not compulsory, that the majority would not welcome a
summative examination at the end of a two-year training period and that nearly
all thought it was right that postgraduate education for dentists should be
compulsory. Of respondents 66% felt that dentists with postgraduate
qualifications should be given a higher salary while over 70% felt that
specialisation would become more important in the future. Young dentists are very
much in favour of postgraduate education but do not want a rigid career pathway
laid down for them.
PMID- 9759056
TI - From need-based to want-based dentistry: redefinition of a profession.
PMID- 9759057
TI - Two-year performance of glass-ceramic insert-resin composite restorations:
clinical and scanning electron microscopic evaluation.
AB - OBJECTIVE: This study evaluated the 2-year clinical performance of beta-quartz
resin composite restorations. METHOD AND MATERIALS: Twenty-two glass insert-resin
composite restorations were placed. Restorations were placed in 6 molars, 12
premolars, and 4 incisors. After 2 years, clinical assessment of the restorations
was made by three operators according to the US Public Health Service criteria.
Scanning electron microscopic evaluations were made by replica technique.
RESULTS: Nineteen restorations were graded Alfa and three restorations were
graded Bravo for color match. Twenty-one restorations were graded Alfa and one
restoration Charlie for proximal contact, marginal integrity, and anatomic form.
None of the restorations showed marginal discoloration, tooth sensitivity, or
caries. CONCLUSION: Glass-ceramic insert-resin composite restorations exhibited
excellent performance after 2 years of clinical service.
PMID- 9759058
TI - An in vitro and in vivo evaluation of various implant-cleaning instruments.
AB - OBJECTIVE: The surface roughness caused by four implant scalers (Premier/Hawe
Neos, Advanced Implant Technologies, Hu-Friedy, and Nobel Biocare) on a titanium
abutment was assessed in a standardized in vitro situation, and operators were
asked to evaluate the clinical usefulness of each instrument. METHOD AND
MATERIALS: Twenty-four evaluators scored scanning electron micrographs of
abutment surfaces scaled for 15 minutes with each instrument. Twelve operators
used each instrument on at least three implant recall patients and scored each
for ease of access; efficacy in deposit removal; overall convenience; distance
reached subgingivally; scaling time per abutment; and overall preference.
RESULTS: The Advanced Implant Technologies scaler created a significantly rougher
surface than all other instruments. The Premier/Hawe-Neos and Advanced Implant
Technologies instruments were significantly preferred in most categories by the
operators. There was no statistically significant difference in scaling time per
abutment. CONCLUSION: The Premier/Hawe-Neos instrument combines operator
acceptance with less damage to the abutments, and, of the instruments tested, is
the scaler of choice.
PMID- 9759059
TI - Cicatricial pemphigoid (benign mucous membrane pemphigoid).
AB - Cicatricial pemphigoid is a chronic mucocutaneous bullous condition. It is a
heterogenous autoimmune disease, characterized by the production of
autoantibodies against basement membrane zone antigens. The target antigens in
cicatricial pemphigoid appear to be lamina lucida proteins involved in human
keratinocyte adhesion to extracellular matrix. Cicatricial pemphigoid primarily
affects persons older than 40 years and appears to have a 2:1 predilection for
women, without racial or geographic bias.
PMID- 9759060
TI - Gingival involvement in mucous membrane pemphigoid.
AB - A 60-year-old woman with clinical features of desquamative gingivitis had a
history of painful, blistering gingival lesions for more than 2 years. There were
no other accompanying mucosal or skin lesions. Clinical examination revealed
erythematous and edematous gingiva with ulcerated areas and evidence of intact
and ruptured bullae. White plaquelike lesions were also noted. Gingival
manipulation caused epithelial desquamation. Light microscopic examination of
biopsy specimens from the perilesional gingival tissue showed separation of the
oral gingival epithelium and connective tissue at the margin of the collapsed
bulla. A moderately intense inflammatory infiltrate was present in the connective
tissue. Direct immunofluorescent microscopy revealed a continuous linear
deposition of immunoglobulin G and C3 at the basement membrane zone. On the basis
of clinical, histopathologic, and immunofluorescent findings, the diagnosis of
mucous membrane pemphigoid was made.
PMID- 9759061
TI - The effectiveness and side effects of 0.1% and 0.2% chlorhexidine mouthrinses: a
clinical study.
AB - OBJECTIVE: The study compared two commercial chlorhexidine mouthrinses
(Chlorhexamed 0.1% and Corsodyl 0.2%) for their effects on dental plaque and
gingival inflammation, their side effects (eg, tooth staining and mucosal
irritation), and patient acceptance. METHOD AND MATERIALS: One hundred thirty
healthy volunteers were randomly distributed into two groups of 65 each. Each
volunteer had gingivitis or chronic marginal periodontitis and used the rinse two
times a day for 4 weeks. The sulcular bleeding index, approximal plaque index,
gingival index, and a discoloration index were taken at baseline and once a week
thereafter. The patients were questioned about taste disturbances, mucosal
irritation, and their perception of the taste of the mouthrinse. RESULTS: In both
groups, after 4 weeks, the mean sulcular bleeding index, approximal plaque index,
and gingival index scores had decreased significantly. The discoloration index
had increased significantly in both groups. There were no statistically
significant differences between the two mouthrinses in any of these measurements.
There were no significant differences in side effects reported by the two groups.
CONCLUSION: The increase in concentration of chlorhexidine provided no clinical
advantages or disadvantages.
PMID- 9759062
TI - Nightguard vital bleaching removes brown discoloration for 7 years: a case
report.
AB - Nightguard vital bleaching with 10% carbamide peroxide was used to remove a brown
stain from the maxillary central incisor of a 13-year-old-boy. After 7 years,
during which there was no touch-up treatment, the discoloration had not returned.
This conservative technique should be considered before more invasive procedures
for the treatment of discolored vital teeth in young patients.
PMID- 9759063
TI - Family violence prevention: dentistry's attitudes and responsibilities.
PMID- 9759064
TI - Oral condyloma acuminatum as an indicator of sexual abuse: dentistry's role.
PMID- 9759065
TI - Abuse detection in the dental environment.
PMID- 9759066
TI - Helmut Heydt--a man for all seasons.
PMID- 9759067
TI - Helmut Heydt, a man with a heart to resolve, a head to contrive, and a hand to
execute.
PMID- 9759068
TI - Helmut Heydt and the unpublished after dinner speech.
PMID- 9759069
TI - The Prosthodontic Society of South Africa. Its origin and history.
PMID- 9759070
TI - Helmut Heydt and the Professional Provident Society.
PMID- 9759071
TI - The role played by the College of Medicine of South Africa in dentistry.
PMID- 9759072
TI - [Drinking behavior of the elderly. Always drink an extra glass].
PMID- 9759073
TI - [Burnout syndrome. From idealism to ... exhaustion].
PMID- 9759074
TI - [Accidents are rarely accidental].
PMID- 9759075
TI - [Shedding light on the gray zone of nursing activities].
PMID- 9759076
TI - [In the confines of anorexia].
PMID- 9759077
TI - [Therapeutic project: intensive treatment: crisis situations].
PMID- 9759078
TI - [The ice was broken].
PMID- 9759079
TI - [Program of accelerated convalescence after major surgery. Promising results].
PMID- 9759080
TI - [Dealing with a patient's violence. Tying the patient down].
PMID- 9759081
TI - [Education at the Morges Nursing School under the eyes of the employers. The
formula works].
PMID- 9759082
TI - [A dignified anniversary celebration. Rive Neuve; 10 years].
PMID- 9759083
TI - [Teaching research in Haiti. Awareness begins at the base].
PMID- 9759084
TI - [Encounter with the mask].
PMID- 9759085
TI - Cost constraints and GME program size.
PMID- 9759086
TI - Locating conference paper.
PMID- 9759087
TI - AHC--community partnerships for interdisciplinary education.
PMID- 9759088
TI - The bonsai master.
PMID- 9759089
TI - The "John McCain Rap": a metaphor for domestic violence.
PMID- 9759090
TI - Achieving better institutional self-study.
PMID- 9759091
TI - Home care--the time to teach about it is now.
PMID- 9759092
TI - Where is the "gene" in the generalist literature?
PMID- 9759093
TI - Encourage qualitative research to improve students' clinical skills!
PMID- 9759094
TI - Emerging lessons of the Interdisciplinary Generalist Curriculum (IGC) Project.
AB - The Interdisciplinary Generalist Curriculum Project (IGC) was funded in 1993 by
the Health Resources and Services Administration with the goal of developing
innovative preclinical generalist curricula in ten of the nation's medical and
osteopathic schools. The IGC successfully completed two competitive cycles in
which ten schools were awarded three-year contracts. Although the long-term goal
of the project is to increase the proportion of medical students choosing
generalist careers, much has been learned thus far about the processes of
curricular change and interdisciplinary cooperation. Drawing on information from
school reports, site visits, external evaluations, academic presentations, and
annual project meetings, this report presents the emerging lessons learned in the
key areas of interdisciplinary collaboration, recruitment and retention of
community preceptors, faculty development, and integration of generalist-related
components into the four-year medical school curriculum. These lessons should
prove useful for other schools embarking upon significant curricular innovations.
PMID- 9759095
TI - Understanding the costs of ambulatory care training.
AB - While patient care has been shifting to the ambulatory setting, the education of
health care professionals has remained essentially hospital-based. One factor
discouraging the movement of training into community-based ambulatory settings is
the lack of understanding of what the costs of such training are and how these
costs might be offset. The authors describe a model for ambulatory care training
that makes it easier to generalize about to quantify its educational costs. Since
ambulatory care training does not exist in a vacuum separate from inpatient
education, the model is compatible with the way hospital-based education costs
are derived. Thus, the model's elements can be integrated with comparable
hospital-based training cost elements in a straightforward way to allow a total
costing approach. The model is built around two major sets of variables affecting
cost. The first comprises three types of costs--direct, indirect, and
infrastructure--and the second consists of factors related to the training site
and factors related to the educational activities of the training. The model is
constructed to show the various major ways these two sets of variables can
influence training costs. With direct Medicare funding for some ambulatory
setting-based education pending, and with other regulatory and market dynamics
already in play, it is important that educators, managers, and policymakers
understand how costs, the characteristics of the training, and the
characteristics of the setting interact. This model should assist them. Without
generalizable cost estimates, realistic reimbursement policies and financial
incentives cannot be formulated, either in the broad public policy context or in
simple direct negotiations between sites and sponsors.
PMID- 9759096
TI - Moving a graveyard: how one school prepared the way for continuous curriculum
renewal.
AB - From 1991 to 1996, the faculty at the University of Florida College of Medicine
initiated several significant changes in its curriculum. These changes, included
the introduction of early clinical experience in primary care settings; the
enhancement of active learning experiences in small-group settings; production
and use of computer-based interactive learning materials; increased clinical
teaching in the ambulatory care training in an interdisciplinary primary care
clerkship; effective course and faculty evaluation; establishment and use of an
assessment center for instruction and performance-based evaluations utilizing
standardized patients; creation of a medical education center as the focal point
for logistics support of the teaching faculty and education data handling;
creation of a faculty development program; and initiation of mission-based
budgeting based on the faculty's teaching effort and quality. Because the faculty
were relatively conservative, it was important to identify variables that would
facilitate the introduction of changes and those that might hinder it. The
following factors were most important: interest and support by the dean and
clearly defined delegation of authority to an associate dean; introduction of a
mission-based budgeting process that allocates education funds on the basis of
faculty teaching effort and its quality; a clear understanding of the empowerment
of the curriculum committee; and an identification of the principles that should
guide educational planning and implementation. These efforts are considered the
beginning of the continuous renewal needed to respond to information networking,
scientific and technological innovations, and the fundamental changes in health
care delivery. As these changes have taken place, a shift toward greater
institutional control of the educational program leading to the MD degree has
been evident.
PMID- 9759097
TI - Forum on the future of academic medicine: session IV--the realities of the health
care environment.
AB - At the fourth meeting of the AAMC's Forum on the Future of Academic Medicine in
December 1997, Dr. Paul Griner and Dr. David Blumenthal discussed findings from
their in-depth case studies of how ten academic medical centers (AMCs) were
responding to the changing, more competitive marketplace and what these AMCs were
doing to sustain the missions of their medical schools and teaching hospitals.
Rapid, wide-ranging internal changes are taking place, such as centralizing
management, down-sizing operations, partnering or merging with other schools or
hospitals, revising legal relationships to state governments (for public schools
and hospitals), creating independent corporations, and increasing alliances with
industry. But AMCs will not be able to sustain their vital balancing act between
academia and the health care system unless they can develop ways that both enlist
faculty to meet the demands of the marketplace and also protect academic
productivity. Reforms in faculty governance are taking place, dealing especially
with issues of reciprocal AMC-faculty accountability. Robert Z. Gussin, vice
president for science and technology of Johnson & Johnson, then spoke concerning
how his vast company was dealing with changing conditions, and discussed the
relationships, roles, opportunities, and problems of academia and industry in
carrying out pharmaceutical research. Members then discussed the future of
biomedical research funding, which was seen as being reasonably stable and a
beneficiary of industry's partnering with AMCs and increased federal support. The
meeting closed with a continuation of an earlier meeting's inquiry about the
characteristics of the ideal medical school in the next century and what barriers
would be faced in reaching this ideal. The group agreed again that service to
society should remain schools' major goal, and they described and discussed
several barriers to change, many of them internal. The group had a number of
suggestions about dealing with the barriers, but there was no consensus. The
members did agree, however, that the forum discussions are worthwhile, and one
participant urged that in planning for the future the AAMC broaden its agenda,
since the core values of medicine, nursing, and public health all relate to the
AAMC's mission.
PMID- 9759098
TI - The evolving duty to disclose the presence of genetic disease to relatives.
AB - Under the aegis of the Human Genome Project, research laboratories are
identifying the genetic bases of human diseases almost daily. This explosion in
molecular biology has raised many medical-legal issues about genetic information,
such as privacy, discrimination, and insurability. Less appreciated is another
issue that faces physicians who deal with genetic information in their practices-
their duty to disclose a genetic disease to relatives of their patients who have
the disease. Few cases have addressed the issue directly, and there has been
little statutory and policy development in this area. However, because a
physician's diagnosis of a genetic disease could have such a profound impact on
the patient's relatives, there is a developing duty to consider disclosing
genetic information to relatives. The case law and policy that support such
disclosure reflect the evolution of medicine and the law away from paternalism
toward an expanded concept of legal and moral duty. Since genetic information is
presumed to be confidential by the law, as is essentially all medical
information, guidelines need be developed regarding a physician's duty to
disclose a genetic disease to a patient's relatives. These guidelines should
consider the patient, the genetic test, the disease, and the third-party
relative. Disclosure should be considered for a disease that is serious or fatal,
treatable or curable, and transmitted dominantly with high penetrance. Specifics
notwithstanding, these policies should be developed by physicians who care for
patients and their families, not by lawyers and ethicists with no clinical
training.
PMID- 9759099
TI - Developing curricula in spirituality and medicine.
AB - In recent years patients and some members of the medical community have expressed
the concern that doctors have forgotten about compassion and too often ignore
their patients' spiritual concerns. Patients can and should expect their
physicians to respect their beliefs and be able to talk with them about spiritual
concerns in a respectful and caring manner. Medical schools must teach their
students how to meet these expectations, and health care systems need to provide
practice environments that foster compassionate caregiving. Medical educators are
recognizing the need to bring the art of compassionate caregiving back into the
medical school curriculum. This paper focuses on one approach to achieving this
goal, the study of spirituality and medicine. The authors discuss the
relationship of spirituality and healing, and describe studies that have shown
patients' desire to have spiritual issues addressed by their physicians and the
potential health benefits of spiritual beliefs. Finally, they describe common
elements of the spirituality courses offered by approximately 50 U.S. medical
schools, including 19 schools that have been awarded grants from the National
Institute for Healthcare Research for the development of curricula in
spirituality and medicine.
PMID- 9759100
TI - Managing information technology in academic medical centers: a "multicultural"
experience.
AB - Based on a session at the 1997 conference on Information Resources and Academic
Medicine sponsored by the Association of American Medical Colleges, this article
illustrates how the beliefs and concerns of academic medicine's diverse
professional cultures affect the management of information technology. Two
scenarios--one dealing with the standardization of desktop PCs, the other with
publication of syllabi on an institutional intranet--form the basis of this
exercise. Four prototypical members of a hypothetical medical center community-
the chairman of surgery, a senior basic scientist, the chief information officer
of an affiliated hospital, and the chief administrative officer--offer their
perspectives on each scenario. Their statements illustrate many of the challenges
of planning, deploying, and maintaining effective information technology in the
"multicultural" environment of academic medical centers.
PMID- 9759101
TI - Medicine and the arts.
PMID- 9759102
TI - Rethinking medical education through injury control.
PMID- 9759103
TI - Minority students, affirmative action, and the admission process: a survey of 15
medical schools.
AB - PURPOSE: To assess the current state of admission policies for underrepresented
minorities (URMs) at medical schools. METHOD: In 1997, the author surveyed the
admission directors at the 15 medical schools with the largest URM populations.
The four categories in the questionnaire covered the makeup of the admission
committee, the weights given quantitative factors in admission decisions, the
weights given qualitative factors, and the weight given the applicant's status as
a URM or disadvantaged student. RESULTS: The 12 responding admission directors
provided a wide range of answers as to the makeup of the admission committee and
the weights assigned quantitative and qualitative factors. None of the schools
gave an exact percentage weight to URM status, although one school added points
to a diversity index, which was then used as a quantitative measure. There
appears to be an increasing focus on economic and educational disadvantage.
CONCLUSIONS: The limited parameters of the study prevent the author from offering
definitive solutions. However, the responses to the survey suggest that admission
policies are secretive and widely varied. The academic community must consider
the reasons behind and the consequences of abandoning a forthright approach to
affirmative action.
PMID- 9759104
TI - Comparing the psychometric properties of checklists and global rating scales for
assessing performance on an OSCE-format examination.
AB - PURPOSE: To compare the psychometric properties of checklists, global rating
scales preceded by a checklist, and global rating scales alone in assessing
surgery residents' performances on an OSCE-like technical skills examination.
METHOD: In 1996, 53 general surgery residents with one to six years of
postgraduate training participated in a performance-based examination of
technical skills consisting of eight 15-minute stations (bench-model simulations
of operative procedures in general surgery). Two qualified surgeons marked at
each station, one using a task-specific checklist (C) and a subsequent global
rating scale (Gc), the other using a global rating scale only (G). RESULTS:
Interstation reliabilities measured by Cronbach's alpha were .79 for C, .89 for
Gc, and .85 for G. A series of multiple regressions predicting level of training
from test scores revealed an R2 of .584 for C alone, which increased to .711 when
Gc was entered after (p < .001), and increased to .704 when G was entered after C
(p < .001). However, R2 for Gc alone was .711, and for G alone was .704, neither
of which changed when C was entered into the prediction (p > .10). The R2 for Gc
and G predicting level of training (.725) was not significantly greater than that
of either Gc or G alone. A very similar pattern of results was seen when C, Gc,
and G were used to predict independent evaluations of the operative outcomes.
CONCLUSIONS: Global rating scales scored by experts showed higher inter-station
reliability, better construct validity, and better concurrent validity than did
checklists. Further, the presence of the checklists did not improve the
reliability or validity of the global rating scale over that of the global rating
scale alone. These results suggest that global rating scales administered by
experts are a more appropriate summative measure when assessing candidates on
performance-based examinations.
PMID- 9759105
TI - Internship ratings as a validity outcome measure for an evaluation system to
identify inadequate clerkship performance.
AB - PURPOSE: To determine whether a third-year clerkship evaluation system validly
predicted students' later performance ratings during their internships. METHOD:
Adequacy of students' clerkship performances and the need for remediation were
determined during seven consecutive academic years at the Uniformed Services
University of the Health Sciences F. Edward Hebert School of Medicine using a
criterion-based process including formal evaluation sessions. Internship ratings
of students who needed remediation (remediators) from 1986 to 1993 were compared
with those of students who voluntarily chose fourth-year medicine (non
remediators). Using written questionnaires, internship directors rated the
graduates on a five-point scale for fund of knowledge, attitude, and analytic
ability, and also provided written comments. RESULTS: Responses to questionnaires
were available for 75 of 97 remediators (78%) and 268 of 313 non-remediators
(86%). The remediators were 12.9 times more likely to have low internship
performance scores and 9.4 times more likely to receive unfavorable comments than
were the non-remediators. However, the majority of the remediators (80%) received
only favorable comments. The medicine clerkship grade was more sensitive than the
non-medicine grade-point average in predicting problems during internship (75% vs
8%). CONCLUSION: The medicine clerkship evaluation process detected whether a
student was likely to have problems during internship, and the internship ratings
supported the predictive validity of the evaluation system. The majority of
students who were successfully remediated had no identifiable problems during
internship.
PMID- 9759106
TI - Physicians' and medical students' perspectives on patients' quality of life.
AB - PURPOSE: To compare medical students' and oncologists' perspectives about patient
related quality of life (QOL). METHOD: In 1996, the authors compared the
questionnaire responses of 65 oncologists and 105 medical students in the state
of Hawai'i. RESULTS: Participants returned 146 usable questionnaires (response
rates: 69% of oncologists and 97% of students). Both groups saw pain and
suffering as central to QOL, while medical students also valued autonomy. Both
groups indicated that QOL was at least as important as survival in treatment
decision making. Students were significantly more likely to emphasize the
importance of QOL over survival. Students strongly preferred physician interviews
to assess QOL. Most physicians reported assessing QOL in every patient, but only
one in ten had used a QOL assessment questionnaire. CONCLUSION: Both students and
oncologists expressed considerable interest in QOL and virtually all regarded it
as an important part of care. There were more similarities than differences in
responses. Future educational programs in both medical school and continuing
education should build on these positive attitudes.
PMID- 9759107
TI - Effect of undergraduate college major on performance in medical school.
AB - PURPOSE: To determine whether choice of college major has any effect on
performance in medical school. METHOD: The author analyzed data for 406 students
enrolled in a combined baccalaureate-MD program at Brown University School of
Medicine who had matriculated in medical school from 1989 to 1997, determining
their undergraduate majors and their medical education performances (as measured
by course grades, USMLE, scores and residency program evaluation). RESULTS:
Slightly over half of the students had majored in science or mathematics, about a
third had majored in the humanities or social sciences, and about a tenth had had
double majors or had been independent concentrators. The author found no
statistically significant difference between the medical school performances of
students who had majored in the sciences or mathematics and those who had majored
in the humanities or the social sciences. CONCLUSION: Although preselection bias
may influence medical school performance, this study affirms previous findings
that choice of undergraduate major has little, if any, statistically significant
effect.
PMID- 9759108
TI - The costs versus the perceived benefits of an LCME institutional self-study.
AB - PURPOSE: To calculate the costs versus the perceived benefits of an institutional
self-study done to satisfy the requirements of the Liaison Committee on Medical
Education's (LCME's) accreditation process. METHOD: From postcard questionnaires,
the authors determined the hours spent over 18 months from 1994 to 1996 on the
institutional self-study by 131 self-study committee members and 64 database
compilers at the Medical College of Wisconsin. The committee members also rated
the potential utility of the self-study process and the probability that the
concerns identified by their subcommittees would be addressed. Administrative
costs (self-study coordinating team's hours, supplies, and other expenses) were
tracked using calendars and budget subaccount numbers. Personnel costs were
calculated using salary data from the Association of American Medical Colleges
and the College and Universities Personnel Administrators' survey. RESULTS:
Supplies and equipment for the self-study cost $12,158, and the personnel costs,
based on an 81% response rate, were estimated at $207,384, for a total of
$219,542. The participants in the self-study rated the process as moderately
useful, but believed that there was only a medium degree of probability that
concerns they had identified would be addressed. CONCLUSION: Considering the
costs of self-study, the process might be more useful if attention were focused
less on identifying concerns and more on an institution's demonstrated ability to
successfully respond to problems.
PMID- 9759109
TI - Do clinical breast examination skills improve during medical school?
AB - PURPOSE: To assess the effects of stage of training, gender, and specialty
interest on medical students' breast cancer knowledge, attitudes, and clinical
breast examination (CBE) skills as a case study of the progression of physical
examination skills during medical education. METHOD: In 1996, questionnaires
assessing breast cancer knowledge and attitudes were administered to 493
premedical and first-, second-, and third-year medical students at Northwestern
University Medical School. Silicone breast models were used to evaluate the CBE
proficiency of a subset of 151 students. RESULTS: Breast cancer knowledge was
positively correlated with stage of training (r = .62), with significant
differences between all levels (p < .001). In contrast, first-year medical
students attained the highest mean lump-detection sensitivity (61.5%), followed
by second-year (53.9%) and third-year (43.5%) students (p < .001, first- vs third
year students; p < .10, second- vs third-year students). There was no significant
difference in specificity among the four stages. CONCLUSIONS: The results suggest
that breast cancer knowledge and attitudes are not related to CBE proficiency,
which is a practiced tactile skill. The decline in lump-detection sensitivity
with increased stage of training may demonstrate the need for increased attention
to palpation skills during the clinical years. These findings are consistent with
those of earlier reports that suggest the need for the reinforcement of physical
examination skills during clinical education.
PMID- 9759110
TI - Medical education: can we do better?
PMID- 9759111
TI - A story of change.
AB - In this introduction to Issues and Strategies for Reform in Medical Education:
Lessons from Eight Medical Schools, the authors describe the overall objective of
the supplement, which is to present the qualitative reflections of 12 faculty
members at eight medical schools who worked to reform their schools' curricula as
part of The Robert Wood Johnson Foundation's "Preparing Physicians for the
Future: A Program in Medical Education." They outline the issues addressed in the
reform efforts at all of the eight schools, including health promotion/disease
prevention and ambulatory care, the editors' choice of a "vignette-based" format
for the chapters, and the content of the three appendices that end the
supplement. They conclude with a brief description of the lessons learned by all
participants in the collaborative effort of producing this supplement on
curriculum change.
PMID- 9759112
TI - The process of change: stories of the journey.
AB - This chapter provides an overview of the decisions, activities, events, and
issues that influenced the process of change at the eight schools that
participated in The Robert Wood Johnson Foundation's "Preparing Physicians for
the Future: Program in Medical Education." The author focuses in particular on
three stages of the change process: planning and creating the climate for change,
making the change, and reinforcing the new model. She describes the different
strategies the schools used to work through these stages (in some cases, several
iterations of these stages) and the common lessons participants learned about how
to successfully implement curricular reforms.
PMID- 9759113
TI - Leadership and governance.
AB - In this chapter, the author discusses leadership and governance issues in
implementing curricular reform at the eight schools that participated in The
Robert Wood Johnson Foundation's "Preparing Physicians for the Future: Program in
Medical Education." Leadership is defined as the roles played by key individuals
within a school in facilitating significant curricular change; institutional
governance is the administrative structure through which the curricular changes
were administered. The characteristics of successful leaders as well as problems
caused by poorly chosen leaders are described. The author also discusses how
leaders handled resistance to change and the role of students in overcoming this
resistance at some institutions. The second half of the chapter focuses on
governance structures. The author briefly discusses the role of curriculum
committees, how student and faculty committees at some schools worked to
implement change, and the implementation at each of the eight schools of a
centralized education budget. He concludes with a list of characteristics of
successful leadership and successful governance in the process of curriculum
reform.
PMID- 9759114
TI - Communication and the process of educational change.
AB - In this chapter, the authors describe the role of communication in the process of
curricular reform at the eight schools that participated in The Robert Wood
Johnson Foundation's "Preparing Physicians for the Future: Program in Medical
Education." The collective experience of these eight schools suggests that
despite its general neglect in the discourse on educational innovation, good
communication is a decisive element of any successful reform initiative. The
authors focus this chapter on effective communication patterns for supporting
educational reform. First, the authors discuss a four-stage model of change-
recognizing the need for change, and planning, implementing, and
institutionalizing change--and describe the role of communication in each of
them. They outline the communication strategies needed to promote a sense of
ownership among all participants; structures and mechanisms for supporting
positive communication; and common lessons learned by all schools about
successful communication.
PMID- 9759115
TI - Integrating the teaching of basic sciences, clinical sciences, and
biopsychosocial issues.
AB - In this chapter, the author describes integrating the teaching of the basic
sciences, clinical sciences, and biopsychosocial issues in medical education as
part of the curricular reform efforts initiated by schools that participated in
The Robert Wood Johnson Foundation's project "Preparing: Physicians for the
Future: Program in Medical Education." The author focuses on the approaches the
eight schools adopted, the challenges they encountered, and the lessons they
learned in attempting to implement more integrated curricula. Integration was
promoted both within and among various components of medical education. For
example, in some cases discipline-based courses in the basic sciences were
replaced with interdisciplinary courses. Further, efforts were made both to bring
clinical relevance to the basic sciences and to strengthen basic science in the
clinical years. All the schools also promoted the study of the humanities and
biopsychosocial sciences throughout the curriculum. The author describes problems
encountered in these endeavors, resources needed to support interdisciplinary
courses, the benefits of integration, and common lessons learned by the eight
schools.
PMID- 9759116
TI - Faculty development: a field of dreams.
AB - This chapter describes the faculty development efforts of the eight schools that
participated in The Robert Wood Johnson Foundation's "Preparing Physicians for
the Future: Program in Medical Education." The authors define "faculty
development" as the "enhancement of educational knowledge and skill of faculty
members so that their educational contributions can extend to advancing the
educational program rather than just teaching within it." Faculty development
programs varied widely among the schools. Some schools had active programs in
place, others initiated programs at the start of the project. This chapter
explores the faculty development topics and methods, both shared and unique,
among the eight schools. It then looks at the ways the schools motivated their
faculties to participate in their programs. Finally, it describes some of the
outcome measures that were used to gauge the effectiveness of the faculty
development programs. The authors conclude that the eight schools' approaches and
levels of commitment to their faculty development programs varied. They present
lessons learned from the successes and failures of the various programs.
PMID- 9759117
TI - Instructional methods.
AB - This chapter addresses one of the goals of The Robert Wood Johnson Foundation's
"Preparing Physicians for the Future: Program in Medical Education" grants: to
introduce new methods of instructions along with curricular revisions. Methods of
instruction emphasize "how to teach," in contrast to the curricular reform's
"what to teach." The author explores the various ways in which the eight
participating schools adopted new instructional methods. The author first sets
out the conditions for effective learning, as expressed in earlier research in
cognitive psychology. He then reviews the issues in new instructional methods:
problem-based learning, small-group learning, self-directed learning, and
instructional methods in the service of integration, as well as learning in
outpatient settings and computer-based learning. The author concludes, among
other things, that schools must respect the variety of ways in which students
learns, that some faculty will have to become skilled in unfamiliar teaching
methods, that new instructional methods should be based on empirical evidence of
effectiveness, and that sometimes method may be less important than the skill and
enthusiasm of the teacher.
PMID- 9759118
TI - Student assessment.
AB - This chapter looks at changes in assessing medical students implemented by the
eight schools participating in The Robert Wood Foundation's "Preparing Physicians
for the Future: Program in Medical Education." The eight schools took a variety
of approaches, some working incrementally, others making large, cross
departmental changes. Each school's support for or constraints to change
influenced its approach in assessment. The authors describe the ways in which
students were assessed within their courses and clerkships. They look at specific
forms of assessment, such as self-assessment, feedback, and standardized-patient
assessment. For most of the schools, changes in student assessment were
controlled by course or clerkship directors and managed by faculty. Often,
changes in assessment came after changes in curriculum. Changes were easier to
make in the first two years of medical school than in the clinical years. The
authors also discuss the integration of assessment within the curriculum,
comprehensive performance-based assessments, and situations where change in
assessment did not occur. They discuss the politics of change, and offer a
summary of the eight schools' assessment experiences and the lessons learned.
PMID- 9759119
TI - Evaluating change in medical school curricula: how did we know where we were
going?
AB - This chapter compares and contrasts the primary outcomes and methods used to
evaluate the curricular changes at the eight schools participating in The Robert
Wood Johnson Foundation "Preparing Physicians for the Future: Program in Medical
Education." Each school evaluated its own program. The eight evaluators formed an
ad hoc group to share information, but the schools did not use a common
evaluation system. Although the evaluations were done without common standards,
many of the measures were similar. The schools used such quantitative methods as
measuring students' performances and their choices of specialties, as well as
such qualitative methods as asking students to evaluate their courses and to
participate in focus groups. The authors describe the ways in which evaluative
data were collected and how evaluation drove curricular change. The authors
conclude that program evaluation can sustain schools through the turbulence of
curricular change, and that qualitative data and communicating the results of
evaluations with faculty and students are essential to successful reform.
PMID- 9759120
TI - Reflections on relevance, resistance, and reform in medical education.
AB - This chapter reflects upon the collective experiences of the eight schools
participating in the Robert Wood Johnson Foundation's "Preparing Physicians for
the Future: A Program in Medical Education," highlighting the lessons learned
over the five years of the program. The authors set the context and give a short
history of the program. They discuss the ways in which the processes of change
occurred at the eight schools, commenting on issues of leadership, governance,
communication, faculty development, integration, instructional methods, student
assessment, and program evaluation (all of which received lengthier treatment in
earlier chapters). The authors conclude that changes in all of these areas are
necessary for successful reform of medical education.
PMID- 9759121
TI - Radiography and bone scintigraphy in osteoarthritis of the knee--comparison with
MR imaging.
AB - PURPOSE: Osteoarthritis (OA) is a multifactorial process affecting cartilage and
subchondral bone. Traditionally, plain radiographs and eventually bone
scintigraphy are used to establish the diagnosis, whereas MR imaging, as a
sensitive instrument for early diagnosis, is less commonly used. Therefore, these
methods have been compared in the format of a prospective study of knee OA.
MATERIAL AND METHODS: Individuals aged 35-54 years with chronic knee pain have
been identified. The prevalence of chronic knee pain was 15% (279/2,000). Within
this group, both knees in 61 randomly chosen persons were examined with plain
weight-bearing radiographs of the tibiofemoral joint (TFJ), standing axial
radiographs of the patellofemoral joint (PFJ), and with bone scintigraphy. One
knee (the most painful at inclusion in the study) in each person was examined
with MR imaging on a 1.0 T imager. RESULTS AND CONCLUSIONS: Assessment of the
minimal joint space (MJS) width in the p.a. view of the TFJ in weight-bearing
examinations should be performed with equal weight on both legs and in
semiflexion. The p.a. view of the TFJ and the axial view of the PFJ, as well as
the MJS measurements in these views, were reproducible. MJS of 3 mm in the TFJ
and MJS of 5 mm in the PFJ are limits in diagnosing joint-space narrowing (JSN)
in the TFJ and the PFJ, respectively. There was a high prevalence of meniscal
abnormalities within the narrowed compartments of the TFJ when compared with
those that were not narrowed. With the presence of marginal osteophytes in the
TFJ, there was a high prevalence of MR-detected cartilage defects in the same
joints whether JSN (MJS < 3 mm) was present or not. No such relationship,
independent of MJS, was found between marginal osteophytes and cartilage defects
in the PFJ. The agreement between increased bone uptake and MR-detected
subchondral lesion (increased signal in the STIR sequence) was good. The
agreement between increased bone uptake and MR-detected osteophytes or cartilage
defects was in general poor. Conventional radiography is inexpensive and readily
available. With the increased knowledge about interpreting weight-bearing p.a.
radiographs of the TFJ and standing axial radiographs of the PFJ, these
examinations will, even in the future, be a valuable and competitive technique
compared with a more expensive and sophisticated method such as MR imaging, when
evaluating knee pain. Further studies have to be performed to evaluate whether MR
imaging has the same ability as bone scintigraphy to predict the progression of
the OA process in the knee joint.
PMID- 9759122
TI - American College of Rheumatology 62nd National Scientific Meeting and Association
of Rheumatology Health Professionals 33rd National Scientific Meeting. San Diego,
California, USA. November 8-12, 1998. Abstracts.
PMID- 9759123
TI - Why do women have rheumatic disease?
AB - If gonadal hormones are responsible for the female predominance (gender
discrepancy, sexual dimorphism) that characterizes most autoimmune rheumatic
diseases, pregnancy should be a particularly vulnerable period for onset of new
disease as well as for exacerbation of established disease. Currently available
data support neither the contention: that pregnancy increases incidence nor that
it worsens severity of the common illnesses. Moreover, many illnesses
pathogenetically similar to rheumatic diseases have the same hormonal background
but are not characterized by sexual dimorphism. In nonrheumatic sexually
dimorphic illnesses an environmental, behavioral, or genetic reason for gender
discrepancy is usually present. To explain sexual dimorphism in the autoimmune
rheumatic diseases, the fields of environmental, genetic, chromosomal, and in
utero sex differentiation need further exploration.
PMID- 9759124
TI - Microchimerism and the causation of scleroderma.
AB - The application of molecular techniques to the study of human pregnancy has
resulted in the recognition that there is bi-directional cell traffic during
pregnancy. Recent studies indicate fetal progenitor cells can persist in the
maternal peripheral blood for decades after childbirth. Scleroderma is increased
in women, has a peak incidence following childbearing years, and has clinical
similarities to chronic graft-versus-host disease that occurs after allogeneic
stem cell transplantation. This paper explores the idea that microchimerism is
involved in scleroderma and considers insights gained from transplantation
biology in seeking to understand how microchimerism might contribute to the
pathogenesis of scleroderma. Chimerism means that a body contains cell
populations derived from different individuals and microchimerism low levels of
chimerism. Although highlighted in the study of scleroderma, microchimerism is
also implicated in selected other autoimmune disorders.
PMID- 9759125
TI - Immune modulation (TH1 and TH2 responses) in pregnancy.
PMID- 9759126
TI - Interleukin-3 and pregnancy loss in antiphospholipid syndrome.
AB - Cytokines play an important role in the progression of autoimmune diseases, and
therefore it is not surprising that their levels may be altered in some of these
diseases. Interleukin-3 (IL-3), which is an hematopoietic growth factor as well
as an important factor that aids in embryo implantation and placental
development, was found to be decreased both in pregnant women with
antiphospholipid syndrome (APS) compared with a control group, and in animal
models of APS. Treatment of animals having APS with IL-3 succeeded in prevention
of disease manifestations. In this communication we review IL-3 and APS
interrelationship, and discuss the role of aspirin and other commonly used drugs,
with respect to IL-3 levels in APS.
PMID- 9759128
TI - The effects of prolactin in animal models of SLE.
PMID- 9759127
TI - Neonatal lupus and autoantibodies reactive with SSA/Ro-SSB/La.
PMID- 9759129
TI - Antiphospholipid syndrome in pregnancy--animal models and clinical implications.
AB - The antiphospholipid (APS) syndrome frequently includes severe pregnancy
complications such as fetal wastage and recurrent spontaneous abortions. Animal
models for APS in pregnancy can provide both an understanding of the pathogenic
mechanisms of anti-phospholipid antibodies (aPL), and aid in the evaluation of
various therapeutic modalities in APS. Animal models for APS include both
spontaneously developed diseases, as is the case for secondary APS in mice with
another autoimmune disease, and induced models of APS. The latter includes either
passive induction of disease by antibodies infusion, or active induction via
manipulation of the idiotypic network. This article summarizes the literature
reports of animal models of APS in pregnancy, deal with the various possible
mechanisms of action of aPL in pregnancy, and discuss the treatment options of
women having pregnancy complications of APS.
PMID- 9759130
TI - Placental pathology in systemic lupus erythematosus and phospholipid antibody
syndrome.
PMID- 9759131
TI - Anti-phospholipid autoantibodies--do they have a pathogenic role in infertility?
AB - Anti-phospholipid syndrome includes a variety of clinical manifestations, among
which is recurrent pregnancy loss. Recently, it was suggested that anti
phospholipid antibodies might also have a role in infertility, mainly in
unexplained infertility. Most of the studies report about an increased prevalence
of these antibodies in infertile women; however, data regarding the implication
of these antibodies on treatment outcome (mainly in in-vitro fertilization) and
if there is a beneficial effect of treating these patients with aspirin, heparin
and prednisone--remains still controversial. In this communication we review the
literature reports of association of anti-phospholipid antibodies and
infertility, and deal with the question whether they have a pathogenic role in
these cases.
PMID- 9759132
TI - Treatment of the antiphospholipid syndrome in pregnancy.
PMID- 9759133
TI - Immunomodulation of experimental antiphospholipid syndrome.
AB - The various therapeutic modalities which are found to be beneficial in
experimental antiphospholipid syndrome include: bone marrow transplantation, anti
CD4 monoclonal antibodies, bromocriptine, intravenous immunoglobulins and anti
idiotypes, interleukin-3, and various anti-coagulant and anti-aggregate agents.
The advantage of animal models is the ability to evaluate experimental treatments
that cannot be tested directly on patients. In this paper, we review the effect
of these agents on animal models of antiphospholipid syndrome, their mechanisms
of action, and their clinical implications.
PMID- 9759134
TI - Can we advise ovulation induction in patients with SLE?
AB - The prognosis of systemic lupus erythematosus (SLE) has greatly improved during
the last two decades, now allowing most patients to have a very long survival
including a satisfactory quality of life. Initially considered contraindicated in
SLE due to its overwhelming risks, pregnancy is nowadays allowed in a majority of
patients, and fair results are usually obtained under appropriate management (1
3). Consequently, patients thought to have infertility ask the question of a
possible therapy, i.e. ovulation induction (OI) associated or not with in vitro
fertilization (IVF). Considering the importance of estrogens in the pathogenesis
of the disease, the use of such procedures raise several questions in SLE. Though
data remain to date extremely scarce, the theoretical and practical aspects of OI
in SLE will be briefly reviewed here.
PMID- 9759135
TI - Do sex hormones modulate symptoms of inflammatory joint disease?
PMID- 9759136
TI - Osteoporosis during pregnancy and its management.
AB - Osteoporosis leading to fracture can occur during pregnancy. Bone density may be
low before pregnancy due to recognised causes such as coeliac disease,
osteogenesis imperfecta and previous anorexia nervosa (secondary osteoporosis).
In some patients there is no identifiable cause. This condition is referred to as
"pregnancy associated or pregnancy related osteoporosis"; it is not known whether
pregnancy causes the osteoporosis or merely coincides with it. Typically the loss
of bone leads to vertebral fracture with loss of height or pain in the hips also
sometimes with fracture. Symptoms most often begin in the third trimester of the
first pregnancy and improve after delivery; they do not usually recur in
subsequent pregnancies. The cause is unknown and there is no specific treatment;
follow up bone density measurements show that the osteoporosis slowly improves
post partum. Recent research in non osteoporotic women shows that breast feeding
maintains a low bone density; it is therefore contraindicated in pregnancy
associated osteoporosis.
PMID- 9759137
TI - Heparin-induced osteoporosis.
PMID- 9759138
TI - Pregnancy in systemic sclerosis.
PMID- 9759139
TI - Does SLE flare during pregnancy?
PMID- 9759140
TI - Renal lupus in pregnancy.
AB - The outlook of pregnancy for women with lupus nephritis is usually favourable if
the disease has been quiescent for at least 3 months before pregnancy, and if, at
conception, serum creatinine is less than 140 mumol/l, proteinuria less than 3
grams/25 hours and blood pressure controlled. The risk of fetal loss is, however,
2-3 times higher than in the normal population and pre-eclampsia, prematurity and
fetal growth retardation frequently complicate these pregnancies. Pregnancies in
women with lupus nephritis are high-risk pregnancies and they require intense
fetal and maternal surveillance.
PMID- 9759141
TI - Hypertension in pregnancy and preeclampsia--diagnosis and treatment.
AB - Women who have or develop high blood pressure during pregnancy are all at
increased risk of complications antenatally, intrapartum and in the puerperium.
The increased risk applies to the mother as well to the fetus. Preeclampsia is
the most serious form of hypertensive pregnancy complications. Preeclampsia is,
however, not primarily a hypertensive disease but a disorder induced by factors
dependent on the presence of placenta. The prime target of the placenta dependent
factors is the vascular endothelium. Therefore the complications are associated
with the vascular system, i.e. intravascular coagulation, bleeding and organ
failure following poor perfusion. The fetus is at increased risk due to growth
retardation and hypoxia following placental damage. Treatment of the hypertension
is first indicated if the blood pressure rises to a level of increased risk of
cerebral vascular complications, i.e. above 105-110 mmHg. Delivery is the only
causal treatment and is always indicated if severe maternal or fetal
complications develop.
PMID- 9759142
TI - Prevention of thromboembolism in pregnancy.
PMID- 9759143
TI - Utilization of intravenous immunoglobulin therapy to treat recurrent pregnancy
loss in the antiphospholipid syndrome: a review.
AB - Although experience is still limited, intravenous immunoglobulin therapy for
recurrent pregnancy loss in the Antiphospholipid Syndrome (APS) may represent a
significant advance. APS was widely recognized only fifteen years ago. Pregnancy
loss and thrombosis are the prominent clinical features. Initially, prednisone
was used for treatment of pregnancy loss, but matemal and fetal complications
stimulated searches for alternative therapy. Subcutaneous heparin and low dose
aspirin was next utilized, but although efficacious, there is still a 30% failure
rate, and intrauterine growth retardation, prematurity, and pre-eclampsia are
relatively frequent. In the late 1980's, there were a number of case reports of
successful pregnancy outcomes after treatment with intravenous immunoglobulin
(IVIg) but regimens differed. Series from two centers have confirmed these
initial findings and treatment regimens have become more consistent. Both centers
have reported success with doses of 400 mg/kg/day for 5 days or 1 g/kg/day for
two days each month initiated during the first or early second trimester. Success
rates of 70-100% have been reported, and complications such as pre-eclampsia,
intrauterine growth retardation, and premature births appear reduced, when
compared to prednisone and low dose aspirin or heparin and low dose aspirin.
Several patients who were treated with IVIg also received heparin, making it
uncertain whether heparin may also need to be added to IVIg. Intravenous
immunoglobulin is safe, but expensive. Despite its expense, if IVIG is shown to
markedly decrease matemal and fetal morbidity, it may be the logical treatment of
choice to prevent pregnancy loss in APS.
PMID- 9759144
TI - Intravenous gammaglobulin in pregnancy, the Connecticut experience.
PMID- 9759145
TI - The Medical Birth Registry of Norway; a source for epidemiological and clinical
research.
PMID- 9759146
TI - Obstetrical and neonatal outcome in pregnant patients with rheumatic disease.
AB - Possible associations between inflammatory rheumatic and connective tissue
disease and adverse pregnancy outcome were assessed by using the Medical Birth
Registry of Norway during the years 1967-95. All women with rheumatic disease
were compared to women without such disease. Data on pregnancy outcome and
deliveries were analyzed after adjustment for possible confounding factors. Women
with rheumatic disease had significantly higher rates of preeclampsia, premature
delivery and cesarean section as well a significantly increased relative risk of
SGA children in all diagnostic groups in 1967-95. These findings emphasize the
importance of close monitoring of pregnancy and delivery not only in patients
with connective tissue disease, but also in patients with other inflammatory
rheumatic disease.
PMID- 9759147
TI - Reproductive events and the risk of development of rheumatoid arthritis.
PMID- 9759148
TI - The effect of pregnancy on the vasculitides.
AB - Vasculitis is a clinicopathologic process characterized by inflammation and
necrosis of blood vessels. Classification schemes for systemic vasculitis depend
on the size of the involved blood vessels, the anatomic site, and the clinical
manifestations. The most common primary types of vasculitis are Wegeners
granulomatosus, polyarteritis nodosa, and Churg-Strauss vasculitis. There is
limited information on pregnancy outcome and medication use in these patients
because most of the primary vasculidities occur in older individuals and they are
more common in men.
PMID- 9759149
TI - The teratogenicity of antirheumatic drugs--what is the evidence?
AB - This review addresses on various methods used in the detection of human
teratogenic effects of drug use in early pregnancy. Data are presented from the
new Swedish ongoing recording of drug use in early pregnancy. These data do not
indicate a teratogenic effect of the main antirheumatic drugs used in Sweden.
PMID- 9759151
TI - Nonsteroidal anti-inflammatory drugs during pregnancy.
AB - As inhibitors of cyclooxygenase nonsteroidal anti-inflammatory drugs (NSAID)
given during pregnancy have the potential to cause adverse maternal and fetal
effects. Maternal effects include prolongation of pregnancy and labour, whereas
constriction of the ductus arteriosus, renal dysfunction and hemostatic
abnormalities can occur in the fetus and neonate. Teratogenicity has not been
found for the NSAID surveyed in this review. NSAIDs are excreted in small amounts
into breastmilk with little risk for adverse effects in the suckling infant.
PMID- 9759150
TI - Antimalarial drugs in pregnancy.
PMID- 9759152
TI - The risk of cytotoxic drugs during pregnancy.
PMID- 9759153
TI - Corticosteroids during pregnancy.
AB - In pregnancy, pharmacokinetics of corticosteroids changes. Systemic
corticosteroids are not teratogenic. Pregnant women receiving corticosteroid
therapy suffer the same side effects and benefits as do treated women who are not
pregnant. Clinical experience suggests no abnormalities of children of mothers
treated with usual doses of prednisone and methylprednisolone throughout
pregnancy, but premature rupture of amniotic membranes and low birthweight babies
may occur. Betamethasone and dexamethasone are used to treat the fetus. The
effect on the fetus of bolus doses of methylprednisolone is unknown. Very little
corticosteroid ingested by the mother enters her breast milk. Corticosteroid
therapy in pregnancy is appropriate to control clinically active maternal
illness; to treat an in utero infant suffering from neonatal lupus-associated
carditis; in stress doses (in corticosteroid-treated patients) for labor and
delivery: and, pre-delivery, to induce fetal lung maturation.
PMID- 9759154
TI - [2 significant stages in the management of mucoviscidosis: the French experience
with dornase alfa (Pulmozyme) and the impact in international registries].
PMID- 9759155
TI - [Respiratory evolution of patient with mucoviscidosis treated with mucolytic
agents plus dornase alfa].
AB - AIM: Modifications of bronchial secretions in cystic fibrosis patients account
for the long-lasting use of mucolytic agents, despite the lack of adequately
controlled clinical studies supporting this approach. Hyperviscosity of bronchial
secretions mainly depend on their high DNA content, as a result of degradation of
polymorphonuclear neutrophils mobilized by infection and inflammation. This
phenomenon has led to the treatment of respiratory complications with human
recombinant deoxyribonuclease (dornase alfa). In the present study, we compared
the clinical and respiratory outcome in patients receiving mucolytic agents
followed by dornase alfa, each for 1 year. POPULATION AND METHODS: Fifty-four
patients, aged 5 years or more, have been prospectively followed for 2 years.
They received first a 12-month association of mesna (two nebulisations per day)
and oral ambroxol (60 mg per day, divided in two doses), followed by a 12-month
treatment with one daily aerosol of dornase alfa only (2.5 mg per day). The
primary end-points were the results of pulmonary function tests. Secondary end
points were subjective symptoms, bacterial colonization, consumption of
antibiotics, and clinical tolerance. RESULTS: At the end of the 12-month
mucolytic therapy, a significant decrease of forced expiratory volume/second
(FEV1, -10.5% as compared to baseline values) and forced vital capacity (FVC,
12.8%) was observed. At the end of 12-month dornase alfa, FEV1 and FVC had
increased by 7.7 and 5.3%, respectively. This change was statistically
significant only for FEV1 in most severely disabled patients. However, forced
expiratory flow 25-75% (FEF 25-75) decreased during the 2 year period of
observation, by 5.6% the first year and 4.9% the second year. The mean number of
days with parenteral antibiotics did not statistically differ between both
treatments, except for patients more than 15 years of age. In this subgroup, the
mean number decreased from 40 days in the first year to 27 in the second year (P
< 0.05). Acceptability of treatment by the patients themselves was better with
dornase alfa than with mucolytic therapy. However, several episodes of
hemoptysis, frequent in only one case, were associated with the treatment by
dornase alfa. CONCLUSION: Dornase alfa was associated with a stabilisation, and
even a trend to improvement in pulmonary function tests. This stabilisation is by
itself a very encouraging result. Long-term comparative studies are needed to
evaluate the benefits of dornase alfa in the treatment of respiratory
complications of cystic fibrosis and specify the optimal modalities of its use.
Synergistic combinations with mucolytic therapy and/or anti-inflammatory drugs
could be viewed as a future prospect.
PMID- 9759156
TI - [Effect of rhDNase on the respiratory function and nutritional status of children
and adolescents with mucoviscidosis].
AB - BACKGROUND: In 1994 we started recombinant human deoxyribonuclease (rhDNase) in
every cystic fibrosis (CF) patient whatever his (her) clinical condition,
provided they were aged more than 5 years and forced vital capacity (FVC) was >
or = 40%. POPULATION AND METHODS: We reviewed retrospectively the effects of
rhDNase in 69 CF children and adolescents during a 2-year follow-up. Patients (35
boys, 34 girls) received 2.5 mg of rhDNase once daily from a mean age of 8.5
years (range 5-16.4). Baseline spirometric values (% predicted) and nutritional
status were as followed: FVC = 84.8 +/- 21.7; forced expiratory volume in 1
second (FEV1) = 80.8 +/- 22.2; peak flow = 89.7 +/- 34.2, forced expiratory
fraction 25-75% (FEF 25-75) = 71.8 +/- 32.8; Z score weight/height = -0.41 +/-
1.14; Z score weight/age = -0.48 +/- 1.25, body mass index = 15.4 +/- 1.8;
caloric intake = 107 +/- 25% of recommended dietary allowances (RDA). Patients
had a Shwachman-Kulczycki's score of 87 +/- 9. Spirometric and nutritional data
were analysed after 1, 3, 6, 12, 18 and 24 months of treatment and compared to
baseline values (changes evaluated as percent change from mean baseline for
spirometric data). Shwachman-Kulczycki's score was calculated after 24 months of
rhDNase. RESULTS: An improvement of FVC (+10.7%, P < 0.001) and FEV1 (+12%, P <
0.01) was noted after one month of treatment and was maintained throughout the
following 2 years around 8.7% (6.4-11.4) for FVC and 8.2% (7.3-9.1) for FEV1, P <
or = 0.01. This was particularly observed in children aged 5 to 10 years, in boys
and in patients with a baseline FVC under 70% predicted. There was no significant
change in FEF 25-75. We observed an improvement of daily caloric intake from the
third month (P < 0.05) and of body mass index from the sixth month (P = 0.02).
This was particularly noted in girls. Z score weight/age was improved only during
the first 3 months of treatment while Z score weight/height increased only after
a 2 year follow-up. There was no significant change in Shwachman-Kulczycki's
score after 24 months of rhDNase. CONCLUSION: rhDNase in CF children in effective
on lung function as well as on nutritional status and the response to this
treatment can be evaluated after the first 3 months.
PMID- 9759157
TI - [International registry on mucoviscidosis: comparison of the French data with the
European data for 1995].
AB - BACKGROUND: The Epidemiologic Registry of Cystic Fibrosis (ERCF) is an
international registry, sponsored by Roche Laboratories, collecting data about CF
patients in Europe. The aim of the our study is to compare the French data with
the European data collected during the year 1995. RESULTS: By December 31st 1995,
8,831 patients have been enrolled in Europe, including 1,457 patients in France.
French CF patients are younger (mean age = 12.6 years) than European CF patients
(mean age = 14.6 years). Genotype is better characterised in France (89 vs 75%
for European patients), but only 49% of CF patients are homozygote for the DF508
deletion in France versus 77% in Denmark. Two clinical features of French CF
patients are interesting: 1) presence of Staphylococcus aureus and Haemophilus
influenzae (52%) is more frequent in France than in Europe (65 vs 48% and 52 vs
29%, respectively), 2) lung function tests (forced vital capacity [FVC]), forced
expiratory volume per second [FEV1] are worse in France (P < 0.001) particularly
in the older patients (> 18 years): 39% of these patients in France have a FEV1 <
40% of predicted value compared to only 29% in Europe. Similarly there are fewer
patients in this age group in France (22 vs 31% in Europe) having a FVC > 90% of
the predicted value in France. With regard to the treatment, three differences
emerge: 1) dornase alfa is more used in France (55 vs only 34% in Europe); 2) use
of prophylactic inhaled and oral antibiotics is less common in France than in all
age groups; 3) the use of inhaled corticosteroids and bronchodilators is also
less common in France despite the same incidence of asthma-like symptoms. Finally
we notice that the mean age at death in 1995 is 18.2 years (+/- 2.38) in France
and 20.6 years (+/- 0.85) in Europe. CONCLUSION: These results are preliminary
because 1995 is the first year for ERCF in France and a low percentage of French
CF patients are included for this year. Therefore they must be interpreted with
caution. Nevertheless, we can hypothesise about a relationship between these
results and a less aggressive treatment regimen. The impact of dornase alfa use
on prognosis seems interesting to analyse in future years.
PMID- 9759159
TI - [Early myoclonic epileptic encephalopathy and non-ketotic hyperglycemia in the
same family].
AB - BACKGROUND: Neonatal myoclonic encephalopathy is of lesional or metabolic origin;
non ketotic hyperglycinemia is one of its causes. CASE REPORT: A girl, born from
consanguineous parents, died from myoclonic epileptic encephalopathy at the age
of 3 months. Screening for metabolic disease was negative, except for increased
levels of urine serotonin and 5-hydroxyindol-acetic in cerebrospinal fluid, blood
and urine. Two sisters died with non ketotic hyperglycinemia, corpus callosum
agenesis and clubfoot. CONCLUSION: Familial occurrence of non ketotic
hyperglycinemia and early myoclonic epileptic encephalopathy is uncommon.
PMID- 9759158
TI - [Exhale nitric oxide (NO) and respiratory function measured with body
plethysmography in children].
AB - BACKGROUND: Exhaled nitric oxide (NO) may be a marker of airway inflammation.
Previous studies in adults have shown that the level of NO in exhaled air is
influenced by several factors (breath holding, exercise, etc), or by several
disease (asthma, congestive heart failure, diseases of the upper respiratory
tract, cystic fibrosis, etc). However, few studies have been performed in
children less than 3 years of age. The aim of this study was to determine
endogenous NO levels in children with various diseases during lung volume
measurements. PATIENTS AND METHODS: Fifty-two children aged 18.3 +/- 9.5 months
were studied. The population was divided in two groups, according to the
underlying disease: a group of 39 children with cystic fibrosis (n = 7),
bronchopulmonary dysplasia (n = 17), asthma (n = 7) or recurrent respiratory
tract infections (n = 8) and a second group of 13 children without respiratory
disease. Lung function was measured by whole body plethysmography and several
respiratory parameters were calculated (functional residual capacity [FRC],
compliance and resistances of the respiratory system, trapped volume). NO
production was measured on a chemiluminescence analyzer from mixed exhaled air
collected into a bag, over a period of 5 minutes. RESULTS: NO production was
related to disease: exhaled NO levels were three times higher in bronchopulmonary
dysplasia and cystic fibrosis, compared to NO levels in children without
respiratory disease. They were higher in asthma. They were not altered in
recurrent respiratory tract infections. No correlation was found between
respiratory parameters and NO production. However, exhaled NO levels were
correlated to trapped volume, which defined dynamic part of pulmonary
hyperinflation. CONCLUSION: Levels of endogenous NO in infants were similar to
those measured in adults with and without inflammatory respiratory disease. Lung
distention influenced exhaled NO production.
PMID- 9759160
TI - [Iterative intestinal intussusception and appendiceal mucocele in an infant with
mucoviscidosis].
AB - Cystic fibrosis is a common and potentially life-threatening hereditary disease
which can affect numerous organs, particularly the digestive tract. CASE REPORT:
A 4.5-year-old boy exhibited two little known clinical manifestations: an
appendiceal mucocele and repeated intussusceptions. In spite of an appendectomy,
intussusception relapsed and an ileocolic resection was necessary 2 years later.
DISCUSSION: Appendiceal diseases in cystic fibrosis represent a large spectrum,
ie, distention on the appendiceal lumen, engorged with sticky mucous matter,
which becomes an appendiceal mucocele, peritonitis with an appendiceal
perforation due to delayed diagnosis since acute appendicitis is difficult to
diagnose in these patients. Intussusception is rarely observed in cystic
fibrosis. CONCLUSION: Appendiceal mucocele could be a cause of intussusception.
If an appendectomy is performed, resection of a part of the cecum, around the
appendix, could be useful in preventing again mucocele formation.
PMID- 9759161
TI - [Localized neonatal convulsions and cerebral arterial infarction].
AB - BACKGROUND: Stroke is a rare cause of neonatal seizures. CASE REPORTS: During a 5
year period, eight full-term infants were admitted to hospital for seizures due
to a stroke. Seizures began shortly after birth and were always one-sided. Early
CT scans showed cerebral infarctions. Motor disabilities such as hemiparesis were
found in three out of seven cases; language difficulties were observed in the
same proportion; however all the children had not reached school age. CONCLUSION:
Neonatal localized seizures may be symptomatic of a stroke and therefore justify
a computerized tomography (CT) scan. Motor and cognitive sequelae require early
management.
PMID- 9759162
TI - [Left aortic arch--right descending aorta--right ductus arteriosus (encircling
aortic arch). A rare malformation of the aortic arches].
AB - Abnormalities of the aortic arch which are responsible for tracheobronchial
compression are well known. This case demonstrates the value of magnetic
resonance imaging (MRI) for diagnosis and suggests that recurrent respiratory
symptoms should evoke these abnormalities in infancy. CASE REPORT: The authors
report a very rare malformation of the aortic arch formed by encircling aortic
arch, with left aortic arch, right descending aorta and right ligamentum
arteriosum. It was revealed by airway disorders due to the compression of
tracheobronchial axis by the ligamentum arteriosum. Section of the ligamentum
permitted suppression of obstruction. The diagnosis of these abnormalities is
usually established by means of oesophagogram, tracheobronchial endoscopy,
angiography and MRI. CONCLUSION: In this case, MRI gave a better picture than
angiography. Sections of the ligamentum arteriosum are sometimes ineffective when
compression is due to the aorta itself. Aortic uncrossing, a more complex
operation, is then necessary.
PMID- 9759163
TI - [Use of the intraosseous route in a premature infant].
AB - BACKGROUND: The intraosseous route (IOR) is a rehabilitated vascular access in
emergency situations. Its indications and duration are defined, although the age
limit at which it is usable is not clearly established. CASE REPORT: A 34-week
old preterm neonate, without infection, receiving gastric gavage, developed, at 8
days of life, a severe septic shock requiring ventilatory support and emergency
volume expansion via a subclavian catheter. During the chest X-ray to check its
position, the catheter was unfortunately pulled out. The child presented an acute
desaturation with bradycardia, requiring bag ventilation and endotracheal
epinephrine. The umbilical vein being unusable, an intraosseous access (20 G,
distal hole, Cook) was performed at the upper tibial level to continue
resuscitation and left in place for 14 hours to infuse antibiotics, inotropic
support, blood products and colloids. Blood cultures grew Klebsiella pneumoniae.
After a severe initial phase, course was favorable with normal examination at 3
years without complication of the IOR. DISCUSSION: To our knowledge, it is the
youngest child in whom IOR was performed. For neonates and especially preterms,
the site of puncture is just below the tibial superior tuberosity, otherwise
there is a risk of fracture of the diaphysis. This risk justifies the control of
the IOR by X-ray. The place of the IOR among emergency vascular accesses in
neonates, seems to us to be reserved to situations when umbilical vein is
unusable. CONCLUSION: Although no study compared IOR to superior longitudinal
sinus access, we suggest to reserve the sinus access only when IOR has failed,
because of its potential cerebral complications.
PMID- 9759164
TI - [Genetic basis of Prader-Willi and Angelman syndromes: implications for the
biologic diagnosis].
AB - Prader-Willi and Angelman syndromes are two genetic diseases whose clinical
diagnosis is often impaired by a wide variability in some clinical findings. New
insights in the genetic basis of these disorders allow the proposition of a
biological approach to detect almost all Prader-Willi syndrome patients and over
80% of Angelman syndrome patients. Moreover, the results of these tests are
indispensable for the evaluation of the recurrence risk.
PMID- 9759165
TI - [Legislative and ethical aspects of drug experimental in children and
adolescents].
AB - Experimentation of drugs in children meets with ethical and legal difficulties.
After studying historical development of drug trials regulation, the different
ways to define the modalities of clinical trials (law, technical aspect,
deontology, ethics) are described. The importance of the informed consent and its
particularities when children are concerned are emphasized. Finally, it appears
ethical and necessary to practice drug trials in children in order to obtain safe
and efficient drugs and prescriptions in pediatrics.
PMID- 9759166
TI - [Intestinal malrotation complicated by intermittent and recurrent volvulus].
PMID- 9759167
TI - [Follow-up of the premature infant: prevention of severe diseases and sudden
death. Role of polysomnography].
AB - Incidence and severity of apnea and bradycardia in preterm infants may be related
to the immaturity of the respiratory control mechanisms. In addition, there is a
steadily increasing risk for sudden death with decreasing birth weight or
gestational age during the first year of age, justifying the search for a
specific preventing strategy for very low birth weight (VLBW) infants. The
purpose of this paper is to define practical preventive guidelines for VLBW
infants at the time of discharge from the neonatal intensive care units.
Polysomnography appears as a useful method to detect those among the VLBW infants
who are at risk of life threatening events and may need home monitoring.
PMID- 9759168
TI - [Home management of bronchopulmonary dysplasia].
AB - Bronchopulmonary dysplasia remains a significant clinical problem associated with
the success on survival of neonatal intensive care and has become the common est
cause of respiratory insufficiency in infants. The severity of the disease is
highly variable from asymptomatic chronic lung disease to patients needing home
care with continuous oxygenotherapy and artificial ventilation. Management must
try to insure not only appropriate growth and neurodevelopment but also
satisfactory well being of the patients. Current medications (aerosoltherapy,
diuretics, steroids), rules for oxygenotherapy, follow-up and expected evolution
are discussed according to the severity of the disease.
PMID- 9759169
TI - [Surveillance of the very-low birthweight infant: growth and nutrition].
AB - In very low birth weight (VLBW) infants careful growth and nutritional
supervision are necessary in order to reduce the incidence of persistent growth
retardation after 2 to 3 years of age. Recently, post-discharge formulas with
higher protein, energy and mineral content has been developed with the aim to
promote catch up growth and mineral accretion during the first months of life.
Based upon the most recent nutritional and growth data, the authors propose
guidelines for the nutrition and growth follow-up of VLBW infants after discharge
from the neonatal unit.
PMID- 9759170
TI - [The premature infant confronting community-acquired infections. Which
prophylaxis?].
AB - Preterm infants are at high risk of severe community acquired infections. In
particular viral respiratory infections, mainly respiratory syncitial virus
infections (RVS), are responsible for a high incidence of rehospitalizations of
preterm infants during their 2 first years of life. Prevention relies upon 1/the
application of an immunization program identical to the program applied to normal
term infants, a cardiorespiratory monitoring during 48-72 hours following
immunization being recommended in those infants who carry a risk of recurrent
apnea; 2/general measures with a demonstrated protective effect, i.e., breast
feeding, elimination of smoking at home, and when possible limitation of contacts
with infant and children communities. Immunoprophylaxis against RVS infections
has been shown to be effective in reducing the severity of RVS infections in
preterm infants but is presently not available in European countries.
PMID- 9759171
TI - [Bacterial infections in the course of varicella: the role of NSAID?].
PMID- 9759172
TI - [Drepanocytosis: is double-heterozygote S/C less severe than homozygote S/S?].
PMID- 9759173
TI - [Type anti-SGPG antiglycolipid antibodies and Miller Fisher syndrome].
PMID- 9759174
TI - [Allergy to hydrolysed cow milk proteins in premature twins].
PMID- 9759175
TI - [Difficulty in measuring the viral load in the course of a HIV infection in the
infant].
PMID- 9759176
TI - [Schistosoma haematobium in an infant: a duodenal infection].
PMID- 9759177
TI - [Arterial puncture in the premature newborn guided with a pulse oximeter probe].
PMID- 9759178
TI - [Advances in the genetics of peripheral neuropathy in childhood].
PMID- 9759179
TI - [Prematurity and neurologic sequelae: a hope for prevention?].
PMID- 9759180
TI - [Retrospective survey of fluoroquinolone use in children].
AB - BACKGROUND: Fluoroquinolones (FQ) are contraindicated in children because of the
risk of cartilage damage. POPULATION AND METHODS: A retrospective survey
concerning the use of FQ in children during the first 6 months of 1993 was
organized in 1994. One hundred and sixty-seven Heads of pediatric departments
were questioned. RESULTS: One hundred and fifty (90%) of those surveyed
responded: 62 (41.3%) were FQ prescribers, 83 (55.3%) were non prescribers and
five (3.4%) were not able to answer. Among the 62 prescribers of FQ, 17
departments (27%) were not able to indicate the number of prescriptions and 45
departments (73%) reported one to 75 prescriptions during the study period.
Twenty-one departments out of the 45 were not able to identify the children
treated with FQ. We obtained a group of 104 children aged 9.0 +/- 5.0 years (mean
+/- standard deviation [SD]), treated with 165 courses of FQ during 20 +/- 45
days (1-535 days) with concomitant treatments for 132/165 courses (80%). Fifty
children (48%) were suffering from cystic fibrosis, 37 children (36%) were not,
and, in 17, the diagnosis was not determined (16%). The FQ treatment administered
either orally (73%) or intravenously (26%) was ciprofloxacin in 69% of the
courses with a 25.1 +/- 7.0 mg/kg/day oral dose (mean +/- SD dose), and a 23.5 +/
11.4 mg/kg/day intravenous dose, pefloxacin in 23 courses/165 (14%) with a 17.2
+/- 3.8 mg/kg/day dose, ofloxacin in 15 courses/165 (9%) with a 21.0 +/- 11.9
mg/kg/day dose, norfloxacin in 13 courses/165 (8%) with a 25.6 +/- 7.5 mg/kg/day
dose. Twenty-one adverse events were reported in 17 children (16%) (11 of them
with cystic fibrosis). These were cutaneous events (photosensitivity, cutaneous
eruption) in eight courses, rheumatologic events (arthralgia, arthritis) in seven
courses and gastrointestinal events (nausea, vomiting, diarrhea) in three
courses. CONCLUSION: This survey shows that FQ are prescribed in children
although their use is not approved in this age group and that numerous side
effects have been recorded. The absence of exhaustive information (due to the
retrospective nature of the survey) and the difficulties in interpreting the side
effects for which validity and causal assessment have not been worked out
according to a standardized method and in the absence of a control group stress
the need for a prospective study.
PMID- 9759181
TI - [Factors influencing the duration of breast feeding. A study of 150 women].
AB - BACKGROUND: The duration of breast feeding has not yet been thoroughly described
in France. A prospective survey has been performed on 150 breast feeding mothers
to determine its duration. The objective of this study was to analyse predicting
factors of this duration. METHODS: A questionnaire including sociological,
psychological and medical variables was completed by the mothers and fathers.
After discharge, the mothers were contacted every month by a physician until the
completion of weaning. RESULTS: The median duration was 10 weeks. By univariate
analysis, several variables were associated with a longer duration: decision to
breast feed before pregnancy (12 weeks vs 9 weeks; P < 0.01), multiparity (17
weeks vs 12 weeks, P < 0.05), high paternal social level (14 weeks vs 9 weeks, P
< 0.001), high maternal education level (12 weeks vs 9 weeks; P < 0.05), mother's
idea of "bad" milk (9 weeks vs 30 weeks; P < 10(-6), satisfied mothers (11 weeks
vs 2 weeks; P < 0.001), motivation to breast feed (P < 0.05), baby and mother in
the same room during the night (13 weeks vs 10 weeks; P < 0.05), and formula
supplementation (6 weeks vs 13 weeks; P < 0.01). The mother's return to work was
related to a decline in the breast feeding rate at 12 weeks, yet working women
generally breast fed the most frequently before returning to work, and many women
breast fed and worked concomitantly. A Cox multivariate analysis took into
account six significant variables: "bad" milk (lower duration), mother who had
been fed, mother satisfied with breast feeding, multiparity, high maternal
education, closer proximity of baby to mother (longer duration). DISCUSSION: The
duration in our study is longer than in other studies in France. Predictive
factors are sociological, linked to maternal education, and psychological, with
antecedent of mother breast feeding and decision before pregnancy. The role of
the mother's occupation was not very important because working women are
generally at a higher social level. The role of the father was analysed, as well
as the role of professional workers, family and breast feeding women's
associations. CONCLUSION: Factors of breast feeding duration can be somewhat
modified, but it is necessary to respect the plans of both the mother and the
father. However, early assistance in the hospital and after discharge can help
parents realize their plans for prolonged breast feeding and helps obviating the
cessation of 20% of mothers during the 1st month.
PMID- 9759182
TI - [Neurogenic bladder in children with acute transverse myelopathy].
AB - BACKGROUND: Neurogenic sphincter dysfunction may result from acute transverse
myelopathy. The aim of this paper is to study the course of such a dysfunction
and to propose management techniques. PATIENTS AND METHODS: The files of 21
children admitted at the mean age of 8 years 5 months (2 to 14 years, 8 months)
for acute transverse myelopathy were retrospectively studied. RESULTS: Bladder
sphincter dysfunction occurred in the first days of disease in 85% of these
patients. Abnormal perception of micturition was one of the most constant and
specific symptoms. Anorectal function was also impaired. Complete regressive
course was noted in 38% of patients, minor sequellae in 39% and major sequellae
beyond 6 months of course in 23%. None upper tract deterioration was noted after
3 years of course. Factors of favorable prognosis were early motor function
recovery (especially recommencement of walking before 20 days) and early
management of bladder dysfunction (inability to void had better prognosis than
urinary incontinence). CONCLUSION: Early systematic bladder drainage in case of
inability to void might be essential for improved prognosis.
PMID- 9759184
TI - [Latrodectism in a child].
AB - BACKGROUND: The malmignatte Latrodectus mactans tredecimguttatus, commonly known
as a black widow spider, can be found in the Mediterranean region. Its bite is a
cause of a rarely seen syndrome called latrodectism. CASE REPORT: During a visit
to Corsica, a 13-year-old boy developed abrupt severe abdominal pain and
spasmodic muscular contractions, headache and vomiting. The patient was restless
and experienced hallucinations including distressing visions of death. His high
blood pressure (154/100 mmHg) returned to normal within 3 days. Clinical
examination revealed dyspnea and facial edema associated with
blepharoconjunctivitis and hyperreflexia, together with a scattered erythema and
pruritus. These changes took place within minutes, after a probable black widow
spider bite. The abdominal and neuropsychiatric symptoms disappeared after 5
days. Treatment with calcium gluconate, paracetamol, phloroglucinol and
hydroxyzine had no effect, but diazepam decreased the acuteness of the symptoms.
Anti-venom serum was not used. CONCLUSION: Diagnosis of latrodectism must be
based on clinical and epidemiological data. Erroneously diagnosing surgical acute
abdomen, renal colic, meningitis, tetanus or opioid withdrawal would entail
incorrect treatment.
PMID- 9759183
TI - [Exploration of 112 children suspected of amoxicillin allergy. Indications and
efficacy of oral provocation test].
AB - BACKGROUND: One to 10% of treatments using betalactams, particularly synthetic
penicillin, are complicated by allergic reactions, usually cutaneous, and not
easily imputable to immunologic sensitization in children. PATIENTS AND METHODS:
The aim of this study was to identify, using cutaneous and biological tests,
those from a group of 112 children suspected of amoxicillin allergy (evidenced by
rash) who were actually sensitized, and to confirm the absence of allergy in
others by an oral provocation test (OPT) associated to a long-term survey. The
cutaneous tests were made by prick test and intra-dermo reaction (IDR) with
Allergopen and with amoxicillin or amoxicillin + clavulanic acid. The biological
tests included examination for penicillin and amoxicillin antibodies by using
various techniques including enzyme-linked immunosorbent assay (ELISA)
immunoglobulin G (IgG) and IgE, FARR, radioallergo sorbent test (RAST) and a
histaminoliberation. When these tests were negative, an OPT with the suspected
antibiotic was subsequently performed. RESULTS: Thirty-nine children (36.4%)
confidently presented at least one positive cutaneous test (38 Allergopen, ten
amoxicillin); 25 biological tests were positive (16 ELISA IgE, one ELISA IgG and
eight histaminolibarations), seven times with negative cutaneous test. Forty-five
children were judged to be sensitized to amoxicillin, with only one who
subsequently took amoxicillin again. Among the 67 others, 52 received an OPT, six
of them with moderate cutaneous reactions. Fifty-one (45.5%) children were
allergic and 46 (41%) were allowed to take amoxicillin again; 17 did, one of them
with a benign cutaneous reaction. CONCLUSION: Efficacy and safety of this type of
investigation seems clear; it will have to be confirmed by other studies.
PMID- 9759185
TI - [Focal dermal hypoplasia: description of three cases].
AB - BACKGROUND: Focal dermal hypoplasia syndrome is mainly defined by the association
of abnormalities of extremities, atrophy and linear hyperpigmentation of the
skin, localized deposits of superficial fat, anomalies of the eyes and of the
nails. Neonates are often small for their age. CASE REPORTS: Three sporadic cases
are reported. Mental delay and omphalocele were observed in the first case. The
neurological development was subnormal in the second and an unusual monodactyly
was seen in the third. CONCLUSION: Most cases are sporadic, but in family cases,
an X-linked dominant factor is likely. When a first affected offspring is
observed, skin examination and X-ray should be carried out in parents to evaluate
the risk of recurrence in their children. As the gene site has not yet been
determined, antenatal diagnosis should be suspected on echography when fetal
growth delay is associated to distal limb and/or ocular anomalies.
PMID- 9759187
TI - [Vancomycin and cardiac arrest in the infant].
AB - BACKGROUND: Different adverse effects induced by vancomycin bolus infusion are
described, but cardiac arrest seems rare, in children as in adults. CASE REPORT:
Two infants, 5 and 12 months old, were admitted after cardiac arrest, following
vancomycin bolus infusion in excessive dose. They recovered after prompt
resuscitation and their short term follow-up was normal. CONCLUSION: Two
mechanisms are invoked: anaphylactic shock and direct cardiovascular toxicity.
Both are dose- and infusion rate-dependent, and probably intersubject dependent.
Usually, cardiac arrest is promptly reversed by adequate resuscitation. The rules
of prescription are: adequate dilution and slow rate of infusion. If any adverse
effect occurred, preventive antihistaminic drug therapy should be advised.
PMID- 9759186
TI - [Urinary calculi and Munchausen syndrome].
AB - BACKGROUND: Unlike the so-called Munchausen syndrome by proxy, which is a form of
child abuse, Munchausen syndrome is seldom reported in pediatric literature. CASE
REPORT: Anthony, an 8.5-year-old child, was referred because he passed several
urinary stones. Although biological findings and urinary tract ultrasonography
were normal, intravenous pyelogram showed a round area of decreased density in
front of the anterior urethra, which disappeared from postmicturation X-ray. For
a 1 month period, the child passed 20 stones without intense pain. After
undergoing an appendectomy, he was readmitted for left lumbar pain which
disappeared after passage of a stone. He spent the following 10 months without
any complaint. On later re-admission with similar symptoms, Munchausen syndrome
was suspected because of the discrepancy arising from the emission of stones on
one hand and the absence of nephritic colic, of hematuria and of urinary tract
dilatation on the other hand. Diagnosis of Munchausen syndrome was confirmed by
chemical analysis which reported that samples were in fact ordinary pebbles and
by child's confession, during interrogation without his parents, to having
introduced the pebbles into his urinary tracts. CONCLUSION: When unusual clinical
features are present in children, it is necessary to evoke the Munchausen
syndrome which can be likened to a distress signal revealing the presence of
psychological disorders.
PMID- 9759188
TI - [Periventricular leukomalacia. I. Histological and pathophysiological aspects].
AB - The term 'periventricular leukomalacia' (PVL) usually covers necrotic and/or
gliotic lesions from perinatal origin occurring in the periventricular ring of
telencephalic white matter. PVLs are found post-mortem in one third of brains
from autopsies of premature infants; PVLs are diagnosed in 4 to 10% of infants
born before 33 weeks of gestation and remaining alive more than 3 days after
birth. PVL is very rare in at term infants. The proportion of PVLs from prenatal
origin is estimated between one third and one half of cases. Recent progresses in
neuroepidemiology, developmental neurobiology and imaging methods permit to
revisit the pathophysiology of PVLs on a multifactorial basis. The final result
of these multiple factors seem to be calcium influx due to glutamatergic
overactivation triggered by cytokines, infection and inflammation, and deficit in
neurotrophic factors. Periventricular topography can be explained by properties
of intracerebral vascular wall at this stage of angiogenesis and by perfusion
failure/hypoxia.
PMID- 9759189
TI - [Periventricular leukomalacia and brain protection. II. Diagnosis, sequelae and
neuroprotection].
AB - The term 'periventricular leukomalacia' (PVL) usually covers necrotic and/or
gliotic lesions from perinatal origin occurring in the periventricular ring of
telencephalic white matter. Carrying motor and neuropsychological consequences,
PVLs could be the most severe danger for very premature brains. Positive rolandic
sharp waves recorded on EEG and precocious abnormally echogenous periventricular
images on ultrasound suggest prospective periventricular cysts. Cystic
periventricular cavitations certify the diagnosis of PVL. More subtle lesions of
PVL do not reach the cystic grade and their diagnosis is confirmed by MRI.
Treatment of infections is already available and potentially a tool for
prevention. When the overwhelming glutamatergic signal has been triggered,
neuroprotective agents turning off the excitotoxic cascade, including calcium
blockers, growth factors and others, are promising therapeutic tools.
PMID- 9759190
TI - [Treatment of apnea in prematurity].
AB - Continuous monitoring of premature infants with apnea is mandatory in order to
define the pathophysiology and the type of apnea, and to assess the efficacy and
tolerance of the treatment. Etiological treatment must be first considered before
deciding on a symptomatic treatment adapted to the type of apnea. In our
practice, methylxanthines are the first line treatment considering their
efficiency on the 'central' component of apnea of prematurity. In case of
treatment failure, doxapram or continuous positive pressure can be associated to
methylxanthines, especially when obstructive apnea or hypoventilation are
predominant. The first attempt to stop the treatment is undertaken 4 to 5 days
after complete resolution of apnea, starting with the last treatment used, the
monitoring being maintained 4 to 5 days in order to detect eventual new apnea.
PMID- 9759191
TI - [Radiological quiz of the month].
PMID- 9759192
TI - [What uses for the acellular pertussis vaccine?].
AB - The acellular pertussis vaccine offers a better tolerance as compared with the
whole cell pertussis vaccine. It has also a good protective effect against
whooping cough. However given as a combined pentavalent vaccine for the primary
immunization of infants, it appears to introduce an immune interference leading
to a diminished response to the Haemophilus type b or poliomyelitis valence
according to the type of vaccine. Thus it is recommended that immunization
against whooping cough in France in the coming years uses whole cell pertussis
combined vaccine for the primary immunization of infants at 2, 3 and 4 months,
the acellular pertussis vaccine being used for the booster injections at 18
months and 10-11 years.
PMID- 9759193
TI - [Rabies is a risk for travelling children].
AB - Rabies remains a dreadful disease which kills about 50,000 people per year,
mostly in Asia, Africa, South America and Central Europe. Between 30% an 50% of
the victims are young children. Modern rabies vaccines are safe and immunogenic.
Therefore parents must be informed on the risk of rabies, and pre-exposure
vaccination must be performed for children traveling often or for periods longer
than one month in canine enzootic countries. Post-exposure treatment must be
initiated without delay with modern vaccines wherever available, according to
approved schedules. Pre-exposure vaccination is particularly useful in remote
places where modern vaccines and immunoglobulins are not readily available.
PMID- 9759194
TI - [Assessment of developmental outcome of preterm babies].
AB - Increasing survival of very preterm and sick neonates has lead to more concern
about development outcome. Risk factors include antenatal, perinatal and
socioeconomic factors. Developmental assessment has to be repeated during infancy
till late school age (at term 3, 6, 12, 18, 42 months corrected age ...).
Neurological examination, sensorial assessment and cognitive evaluation with
special attention to visuo-spatial factors are mandatory.
PMID- 9759195
TI - [Prematurity and infant-parent attachment disturbances. Assessment and
intervention].
AB - Premature birth is a factor of impaired infant-parent attachment. In addition it
is frequently associated with other factors of impaired attachment related either
to the infant (mainly the various pathologies of the premature infants and the
hospitalization) and/or to the parents, specially the mother. The main
characteristics of the normal process of infant-parent interaction are described
as a basis for the early recognition and assessment of impaired interaction and
preventive intervention.
PMID- 9759196
TI - [Publishing in French].
PMID- 9759197
TI - [Neuropathic pain associated with septic sacroiliitis].
PMID- 9759198
TI - [Everything mothers want to know about the skin of their newborns].
PMID- 9759199
TI - [Belief and practices of mothers in weaning infants between 0-24 months in
Koumassi, Abidjan, Ivory Coast].
PMID- 9759200
TI - [Treatment of asthma with drug inhalers].
PMID- 9759201
TI - [Management of obesity in children and adolescents requires mobilization of all
specialists].
PMID- 9759202
TI - [Stopping measles with a second dose of vaccine].
PMID- 9759203
TI - [Graft function following renal transplantation in children].
AB - BACKGROUND: Since renal transplantation is known to be the best choice for the
growing child with end-stage renal failure, we prospectively evaluated early and
late graft function in transplanted children. POPULATION AND METHODS: The study
included 78 children (32 girls, 46 boys) 10.4 +/- 0.6 years at the time of
transplantation. Renal investigations were performed at 3, 6 and 12 months post
transplantation and yearly thereafter. Inulin clearance was used to evaluate the
glomerular filtration rate (GFR), and the reabsorption rates of Na, P and Ca were
measured concomitantly. RESULTS: The overall adjusted GFR was approximately 70
mL/min/1.73 m2 and remained unchanged during the first 5 years post
transplantation. In the mean time the absolute GFR increased significantly,
suggesting a remaining capacity for compensatory hypertrophy of the transplanted
kidney. Renal function was significantly influenced by the number of rejection
episodes during the first 2 years post-transplantation but no correlation was
found between GFR and the number of HLA mismatches or the use of preemptive
transplantation.
PMID- 9759204
TI - [Long-term follow-up of children with esophageal caustic stenosis].
AB - BACKGROUND: Long term follow-up of children with esophageal caustic stenosis is
not well known. The aim of the present study was to describe functional, organic
and psychological, as well as social consequences. PATIENTS AND METHODS: Thirty
four children with a mean age of 3 years and 7 months +/- 3 years and 2 months
(ranges: 1 month-14 years and 3 months) were included in a longitudinal study.
Various parameters have been studied: treatment, functional symptoms, nutritional
status (weight/height, body composition) and psychological and social
consequences. chi 2 and Mann-Whitney tests were used for statistical analysis.
RESULTS: Twenty-one patients have been treated by mechanical dilatations whereas
surgery was performed in 12 children; the mean number of dilatations per child
was higher in patients treated by dilatations (21 +/- 17 vs 14 +/- 16; P < 0.05).
The frequency of dysphagia was not different in patients with colon interposition
or not (69% vs 53%; P = 0.1). Nutritional status was not affected by the presence
of esophageal caustic stenosis. Psychological and social consequences were
characterized by scholastic difficulties, anxiety and severe depression. One case
of suicide was observed. CONCLUSION: Children with caustic stenosis should be
followed for a long period of time. A multidisciplinary approach is necessary,
taking into account medical, social and psychological consequences.
PMID- 9759205
TI - [Prevalence of Helicobacter pylori infection in children according to their age.
A retrospective study].
AB - The aim of this study was to evaluate the prevalence of H pylori infection in a
Parisian children population. PATIENTS AND METHODS: During a 3-year period, H
pylori infection was investigated in 623 children admitted to our hospital.
Children were enrolled into two groups; either a symptomatic children group with
clinical gastritis manifestations as infant colics or recurrent abdominal pain
for more than 3 months in whom H pylori infection was suspected, or a control
children group with growth retardation of more than -2 standard deviation (SD).
Ethnic origin for all enrolled children was identified. A written parental
consent was obtained for all children. H pylori infection was identified by
enzyme-linked immunosorbent assay (ELISA) (Cobas Core Roche, IgG, 2nd generation,
Roche, France). RESULTS: H pylori infection was identified in 99 children out of
623 (15.8%). There was no difference between the two groups of children for age,
sex, ethnic origin and prevalence of H pylori infection. The prevalence of H
pylori infection was widely dependent on age and rose regularly with an annual
acquisition rate of 2.1%. The prevalence of this infection varied from 1.8%
during the first year of life to 30% in 15-year-old children. CONCLUSION: The
latter prevalence is quite similar to that found in adults, suggesting that
infection might occur in early life.
PMID- 9759206
TI - [Breast feeding effect relative to age of onset of celiac disease].
AB - BACKGROUND: Age at onset and clinical presentation of celiac disease have often
been related to the age of gluten introduction into the diet. It has also been
shown that breast feeding delays the onset of the disease. PATIENTS AND METHODS:
This retrospective study attempts to evaluate the respective contributions of
these two parameters in the determination of the age at onset of the symptoms in
celiac Tunisian children. RESULTS: One-hundred-sixty-nine children were studied.
Mean duration of breast feeding in our population was 9.6 +/- 8.9 months and mean
age of gluten introduction was 5.6 +/- 3.2 months. The mean age at onset of the
disease was 15 +/- 8.7 months and mean latency time between gluten introduction
and onset of the disease was 9.5 +/- 7.8 months. Both variables, duration of
breast feeding and age at gluten introduction were strongly correlated to the age
at onset of the disease (r = 0.47 and 0.40, respectively). Only breast feeding
was correlated to the variable latency time (r = 0.33). Stepwise multiple
regression analysis showed that the two variables independently influenced the
age at onset with coefficients of regression of 0.90 +/- 0.20 and 0.26 +/- 0.07,
respectively. Only breast feeding influenced the latency time with a coefficient
of regression equal to 0.26 +/- 0.07. DISCUSSION: Our study confirms the
independent effect of breast feeding in the determination of the age at onset of
the disease. Breast feeding has two effects: an indirect effect, by delaying the
introduction of gluten, and a direct effect, by increasing the latency time
between gluten introduction and onset of the disease. CONCLUSION: Prolonged
breast feeding, at least until the 6th month, and gluten introduction started at
least at the 5th month of life, significantly delay the onset of the disease.
Gluten introduction should be done progressively and under breast feeding
protection. Introduction of gluten 2 months before weaning has a protective
effect.
PMID- 9759207
TI - [Unusual presentation of nephroblastomatosis].
AB - BACKGROUND: Nephrogenic rests generally constitute precursor lesions of Wilms'
tumor. We report a case of right nephroblastomatosis with dysmorphic features.
CASE REPORT: An enlargement of the right kidney was incidentally discovered in a
1-year-old girl with dysmorphic features but normal psychomotor development.
Combined ultrasonography and computerized tomography (CT) scan showed right
cortical nephroblastomatosis. Chemotherapy using actinomycin D and vincristin was
successful; however, an hyperechogenic nodule was subsequently found,
necessitating a right nephrectomy. CONCLUSION: The relationship between
nephroblastomatosis and Wilms' tumor is discussed. This case report reminds us of
the importance of a long-term follow-up including echography and CT scan in cases
of nephroblastomatosis.
PMID- 9759208
TI - [Paraplegia due to medullary ischemia after repair of coarctation of the aorta in
an infant].
AB - Paraplegia after repair of coarctation of the aorta is uncommon. CASE REPORT: A 2
month-old boy underwent excision of the coarctation area and primary anastomosis
because of persistent heart failure. Spastic paraplegia was noted some hours
after surgery. Motor deficit partially improved, but bladder dysfunction appeared
some months after. Medullary magnetic resonance imaging (MRI) revealed an
ischemia-related narrowing of the medullary diameter. CONCLUSION: Paraplegia
after repair of coarctation of the aorta, described in adults and infants, is
also seen in neonates. Prevention by preoperative monitoring of somatosensory
evoked potentials is effective in adults, but difficult to perform in very young
children.
PMID- 9759209
TI - [Cystic papillary tumor of the pancreas: a rare etiology of abdominal mass in
children].
AB - BACKGROUND: Malignant pancreatic tumors are very uncommon in childhood. CASE
REPORT: A 13-year-old girl was admitted for investigation of an abdominal mass
with fever. Ten months earlier, clinical examination performed for similar
symptoms found an epigastric mass which resolved spontaneously. Radiological
investigations showed a well-encapsulated cystic tumor in the pancreas. Excision
revealed a papillary cystic tumor of the pancreas. CONCLUSION: Papillary cystic
tumor of the pancreas is an unfrequent cause of abdominal mass in children. Its
excellent prognosis after complete excision is quite different from that of other
malignant pancreatic tumors.
PMID- 9759211
TI - [Intestinal flora in the neonate: impact on morbidity and therapeutic
perspectives].
AB - Studies in recent years have focused on the role that intestinal flora plays in
health and disease. At birth, infant gut colonization begins with bacteria which
are derived from the mother during delivery. Environmental factors (hospital,
hygiene, antibiotics administered to the mother or to the neonate) may contribute
to modification of the type of primary colonizing germs. Afterwards, diet
represents the most important variable by the end of the first postnatal week.
Exclusive breast-feeding promotes growth of Bifidobacteria which have been
associated with the healthy nature of stool flora in infants because of their
potential role in resisting pathogen colonization. Clinical trials have been made
to promote bifidobacteria growth in the feces of bottle-fed infants. In addition,
administration of non-pathogenic micro-organisms (probiotics) has been claimed to
exert a positive influence on host health or physiology, and is a new approach to
the prevention or elimination of infection originating from gut.
PMID- 9759210
TI - [Bacteroides fragilis meningitis revealing a meningorectal fistula].
AB - Cases of meningitis due to Bacteroides fragilis are rare; we report a case
revealing a meningorectal fistula. CASE REPORT: A 2-month-old infant developed a
severe sepsis syndrome following a rectosigmoidoscopy for rectal bleeding. Lumbar
puncture diagnosed bacterial meningitis. Cerebrospinal fluid (CSF) culture
evidenced B fragilis with betalactamase. The initial antibiotherapy was changed
for imipenem-metronidazole, which is at present the recommended antibiotherapy.
Malformation including pre-spinal tumor and meningorectal fistula was evoked on
magnetic resonance imaging (MRI) and confirmed by surgery. The outcome was
favorable after surgery and antibiotherapy. CONCLUSION: B fragilis meningitis are
usually associated with sepsis, whose origin is obvious. In our case, meningitis
was isolated, revealing a meningorectal fistula.
PMID- 9759212
TI - [Vasoactive intestinal peptide: a novel neurotrophic factor].
AB - Vasoactive intestinal peptide (VIP) is a 28-amino acid neuropeptide with potent
growth-related actions on dissociated neural cells. In recent years its role in
brain development has been elucidated: VIP has been shown to be a regulator of
early neurodevelopment and embryonic growth, a stimulator of neocortical
astrocytogenesis and a neuroprotective molecule against excitotoxic and other
neurotoxic substances. Thus VIP appears as a fundamental regulator of brain
growth and development, and a potent neuroprotective agent, possibly involved in
pathological processes such as microcephalies and some neurological impairments
observed in very premature babies. Similarly, VIP and VIP derivatives could
represent a new avenue in the search of therapeutics for excitotoxic lesions of
the developing brain.
PMID- 9759213
TI - [Treatment of chemotherapy induced emesis in children].
AB - In recent years, the management of chemotherapy-induced emesis in children has
been greatly modified by the introduction of a new therapeutic class: serotonin
antagonists. Based on a better knowledge of mechanisms, the treatment now uses
combinations of different drugs. These treatments need to be carefully adapted to
the patient and to the emetic risk of the chemotherapy, also taking into account
the minimal cost. A gradual treatment proposal in five steps is described.
PMID- 9759214
TI - [Radiological case of the month. Lipoma of the omentum].
PMID- 9759215
TI - [Plea for an evaluation of beta hemolytic streptococcal tonsillitis: from
diagnosis to treatment].
AB - There is no justification to maintain a systematic antibiotic treatment of all
tonsillitis as currently practiced in France. Indeed, it is today possible to
exclude the streptococcal origin of tonsillitis with a fair probability using a
rapid diagnosis test. It is therefore mandatory that these tests are made
available to the French practitioner. Additionally, alternatives to the classical
10-day penicillin V treatment of streptococcal tonsillitis must be seriously
considered: shorter duration treatment with oral cephalosporins, macrolides or
amoxicillin have proved to be as efficient and of lower cost; they are also
probably safer due to a better compliance related to the shorter duration.
PMID- 9759217
TI - [Diagnosis and treatment of rheumatic fever].
AB - Rheumatic fever has become rare in France as in most developed countries.
However, recent outbreaks have underlined the need for practitioners to remain
vigilant and to maintain careful prevention. Polyarthritis and polyarthralgia are
the main manifestations of rheumatic fever but they are not specific. Carditis is
a major feature which affects only half the patients; cardiac ultrasonography is
therefore very helpful with respect to positive and false positive diagnoses
resulting from innocent murmurs. Fever, acute phase inflammatory markers, and
evidence of streptococcal infection are of major importance and rheumatic fever
must be disregarded in their absence. The treatment includes: 1) steroids for a 3
month-period; 2) early antibiotic treatment of streptococcal carriage; 3) long
term prophylaxis using intramuscular benzathine penicillin.
PMID- 9759216
TI - [Acute tonsillitis: towards a new therapeutic strategy].
AB - There is a need for revising the current practice for treatment of acute
tonsillitis in France, i.e., systematic antibiotic treatment. There are three
main reasons for this revision: 1) group A betahemolytic streptococcus is
involved in only 20% of acute tonsillitis (80% being viral); 2) rheumatic fever
has become very rare; 3) efficient rapid diagnostic tests are now available,
allowing a selection of patients with streptococcal tonsillitis who must be
treated.
PMID- 9759218
TI - [The ophthalmological follow up of the premature infant must go on after the
neonatal period].
AB - Premature infants with very low birth weight (VLBW: < 1251 g) and/or gestational
age lower than 32 weeks are at high risk of ocular abnormalities. Retinopathy is
a well known complication of the neonatal period, but many abnormalities occur
beyond the neonatal period, and must be carefully screened for years, mainly:
cicatricial retinopathy, myopia, strabismus, glaucoma, retinal detachment and
various functional visual impairments. Guidelines for the postneonatal screening
of these abnormalities are given.
PMID- 9759219
TI - [Hearing impairment in low birth weight infants: warning signs, diagnosis and
rehabilitation program].
AB - The incidence of deafness is high in children born prematurely as compared with
the general population of children. Early start of the rehabilitation being an
important prognosis factor the detection of deafness must be made as early as
possible. Therefore a careful attention must be paid to any early signs of
possible hearing imparment; parents concerns in particular must always be
considered seriously. Diagnosis of deafness rests on behavioural tests and
electrophysiological technics.
PMID- 9759220
TI - [Cerebellum and brainstem ischemic infarction after dog bite to the neck].
PMID- 9759221
TI - [Fetal alcohol syndrome and hypertrophic pyloric stenosis in two brothers].
PMID- 9759222
TI - [Breast feeding: what role for the pediatrician].
PMID- 9759223
TI - [Value of bone mineral content measurement in preterm infants given
corticosteroids for bronchopulmonary dysplasia].
PMID- 9759224
TI - [History of medical education in Amiens].
PMID- 9759225
TI - [Congenital malformations in pediatric tumors].
PMID- 9759226
TI - [Animal models of congenital malformations].
PMID- 9759227
TI - [Dysmorphic syndromes and regulatory genes].
PMID- 9759228
TI - [Pathogenesis: immunologic, infectious and genetic aspects].
PMID- 9759229
TI - [Chronic inflammatory bowel diseases in the child: clinical aspects].
PMID- 9759230
TI - [Treatment of chronic inflammatory bowel diseases in the child].
PMID- 9759231
TI - [Current knowledge of simple transposition of great vessels].
PMID- 9759232
TI - [Simple transposition of great vessels. Physiopathology, current management].
PMID- 9759233
TI - [Transposition of great vessels: history of surgical repair].
PMID- 9759234
TI - [Long-term outcome and prospects in managing transposition of great vessels].
PMID- 9759235
TI - [Diagnostic assessment in neutropenia].
PMID- 9759237
TI - [Diagnosis and evolution of autoimmune neutropenia in the child].
PMID- 9759236
TI - [Neonatal neutropenia].
PMID- 9759238
TI - [Functional respiratory examination in pediatrics: why and how?].
PMID- 9759239
TI - [Functional respiratory testing in mucoviscidosis].
PMID- 9759241
TI - [Respiratory function in respiratory distress syndrome].
PMID- 9759240
TI - [Respiratory function tests in pediatric asthma].
PMID- 9759242
TI - [Treatment of nephrosis in the child].
PMID- 9759243
TI - [Primary IgA nephropathy in the child: natural history, epidemiology and
prognostic factors].
PMID- 9759244
TI - [Genetics and nephrotic syndrome].
PMID- 9759245
TI - [Walking, detection of pathology].
PMID- 9759246
TI - [Equine gait in the child (video recording)].
PMID- 9759247
TI - [The limping child. Orthopedic approach and limits of pediatric orthopedics].
PMID- 9759248
TI - [The child who falls].
PMID- 9759249
TI - [Walking problems in neurology: kinesitherapy and what else?].
PMID- 9759250
TI - [Introduction: basic aspects, problems and outcome in perinatal neurology].
PMID- 9759251
TI - [Prenatal ultrasound diagnosis of anomalies and developmental disorders of the
nervous system].
PMID- 9759253
TI - [Treatment and decision tree in ante- and perinatal neurologic pathology].
PMID- 9759252
TI - [Nuclear magnetic resonance brain imaging in the prenatal period].
PMID- 9759254
TI - [Contributions and expectations of molecular genetics in perinatal neurologic
diagnosis].
PMID- 9759255
TI - [Vaccine trials in ambulatory pediatrics].
PMID- 9759256
TI - [Vaccination strategies of tomorrow... is it necessary to revaccinate rubella,
mumps and rubeola, and when?].
PMID- 9759258
TI - [Treatment of bacterial diarrhea].
PMID- 9759257
TI - [Nosocomial infections in pediatrics. Epidemiologic studies, importance of
research networks. Members of REAPED research].
PMID- 9759260
TI - [Epidemiology of neonatal primary bacterial infections].
PMID- 9759259
TI - [Periodic fever in the child. Survey of Marshall syndrome. Pediatric Infectious
Disease Pathology Group].
PMID- 9759261
TI - [Using milk during acute diarrhea in the infant].
PMID- 9759262
TI - [After milk: what, when, how, why?].
PMID- 9759263
TI - [Malnutrition at the beginning of life: long-term effects].
PMID- 9759264
TI - [Is it necessary to continue admitting children to the general hospital?].
PMID- 9759265
TI - [Is it necessary to train generalists in urgent pediatric care? Experience with
an inter-university curriculum of urgent care in pediatrics in the Rhone-Alps
region].
PMID- 9759266
TI - [Success and vicissitudes on organizing urgent care in pediatrics: presentation
of a project of urgent pediatric medico-surgical care].
PMID- 9759267
TI - [Imaging network and connection in pediatric care].
PMID- 9759269
TI - [Gilbert's disease in 1998].
PMID- 9759268
TI - [Noonan syndrome: an enigma].
PMID- 9759270
TI - [Basedow disease in children: clinical and evolutive aspects].
AB - PATIENTS AND METHODS: The initial symptomatology and long-term effects of
antithyroid drug treatment are reported in children aged 11.7 +/- 3.2 years (52
girls, 16 boys) with hyperthyroidism due to Graves' disease. RESULTS: A family
history of thyroid pathology was found in half of the cases: 7% (five out of 68)
of our patients have had another autoimmune disorder associated with
hyperthyroidism. The most frequent and permanent clinical symptoms at diagnosis
were goiter and tachycardia. Antithyroid drug treatment was always proposed at
first line and resulted in a rapid decrease in clinical and biological signs of
hyperthyroidism. Subtotal thyroidectomy (n = 19) was mostly performed because of
non-compliance or recurrence of hyperthyroidism after medical treatment
withdrawal. Significant adverse reaction (leukoneutropenia) was observed in only
one patient. Survival remission times analysis (remission being defined as
clinical and biological euthyroidism for more than 1 year after antithyroid drug
withdrawal) realised in 50 subjects followed up for at least 2.5 years showed
complete remission in 55% of the patients treated exclusively medically (n = 27),
when lost to follow-up or surgically treated subjects were considered as
incomplete observations. On the whole studied population (n = 50), the remission
rate was of 30% (n = 15) with an average follow-up period after medical therapy
withdrawal of 5.2 +/- 3.0 years (range: 1.4-12.3 years). At present, ten out of
15 can be considered as healed (remission time for at least 2.5 years). Moreover,
according to survival analysis, 75% of the remissions have a probability to occur
in a delay of 4.6 +/- 1.0 years after the beginning of medical treatment.
CONCLUSION: In this population, no remission after 7 years of antithyroid drug
therapy was observed. Remission predictive factors remain to be defined.
PMID- 9759271
TI - [Treatment of infantile spasms with vigabatrin as first-line therapy and in
monotherapy: apropos of 70 infants].
AB - BACKGROUND: Steroids (hydrocortisone or ACTH) still remain the usual treatment
for infantile spasms (IS). However, since 1990, some authors have reported the
efficacy of vigabatrin (VGB), especially in cases related to tuberous sclerosis.
POPULATION AND METHODS: Seventy children with infantile spasms were treated by
VGB first line monotherapy. Modalities of treatment and monitoring were the same
for all children. VGB was given at the daily dose of 100 mg/kg during 1 week. If
spasms persisted, the daily VGB dose was increased to 150 mg/kg during a 2nd
week. In case of persistence of IS, on the 15th day, hydrocortisone was then
added to VGB. Of the 70 infants, 39 were symptomatic and 31 cryptogenic. RESULTS:
On VGB, 37 children (54%) stopped having IS within a mean 3.5 days. Response to
VGB was different according to etiology. Among cryptogenic cases, 22 infants
(71%) definitively stopped having spasms and only one relapsed. Among symptomatic
cases, only 15 infants (38%) stopped having IS, and half (8/15) relapsed. VGB
mean daily dose at cessation of spasms was 114 mg/kg. Side effects were transient
drowsiness (27%) and agitation (12%). Mean follow-up was 10 months (1-24 months).
Seventy-five percent of the infants presenting with a focus of spike after the
1st month of treatment relapsed. CONCLUSION: Infants with cryptogenic spasms have
a good response to VGB monotherapy. When mental retardation is noticed before IS,
and MRI is normal, there is no efficacy. In these cases, the best treatment seems
to be prolonged corticotherapy associated with VGB.
PMID- 9759272
TI - [Definition and prevalence of school-age multi-handicaps].
AB - BACKGROUND: Regulations concerning services for handicapped children in France
have defined the notion of multi-handicap. There are, however, divergences in the
procedures for applying this definition, and differences in the prevalence in
different areas. This study is aimed at clarifying these two points. POPULATION
AND METHODS: A survey in three French departments provided data about disabled
children born between 1975 and 1985 who received services from the departmental
committee for special education or from day hospitals. The data was
systematically collected by a physician using medical files. RESULTS: The results
showed that the group of multi-handicapped children was heterogeneous. The most
restrictive definition (motor disability with profound mental retardation, bed
ridden or restricted to a chair) resulted in a prevalence of 0.73%. A broader
definition based on the concept of zero autonomy, but excluding mild or moderate
mental retardation, resulted in a prevalence of 1.28%. CONCLUSION: The importance
of specifying the objectives of a definition selected for operational reasons is
stressed in order to improve the estimation of specific needs.
PMID- 9759273
TI - [Comparison of the effect of subcutaneous injection of adrenaline and terbutaline
in asthma crisis in infants].
AB - BACKGROUND: Edema of the mucous membranes lining the airways is a major factor of
airway obstruction in asthma. Stimulation of both alpha and beta-adrenergic
receptors is thus logically useful to reduce edema through vasoconstriction and
to cause smooth muscle relaxation. The aim of this work was to compare the
effects of subcutaneous epinephrine vs terbutaline for treating acute attack of
asthma in infants. PATIENTS AND METHODS: Fifty-four infants aged less than 30
months admitted for acute asthma attacks were included in this study. None had
previous cardiovascular or definite pulmonary disease and none had tachycardia
above 200/min. The patients were randomly given subcutaneous epinephrine, 10
micrograms/kg (n = 28) or subcutaneous terbutaline at the same dosage (n = 26).
RESULTS: Improvement in accessory muscle use, oxygen saturation, PaO2 and PCO2
was similar in both groups. The respiratory rate was significantly improved after
administration of epinephrine (P = 0.05). No adverse effects were seen in either
drug. CONCLUSION: Subcutaneous administration of epinephrine is as effective as
terbutaline in treating acute attack of asthma in infants. This drug, easy to use
and of low-cost, could be the treatment of choice in developing countries.
PMID- 9759274
TI - [Familial Romano-Ward syndrome. Apropos of 2 new observations].
AB - BACKGROUND: Congenital long QT syndrome is rare, usually revealed by bouts of
syncopal attacks secondary to effort or strong emotions, and more rarely by
atypical epileptic crisis. CASE REPORTS: We report a family history of two boys
whose mother and grandmother both died suddenly a few days after delivery. The
oldest child was 10 years old when admitted to hospital for recurrent loss of
consciousness. Neurological examination and biological assays were normal;
electrocardiography (ECG) revealed a prolonged QT interval of 0.59 seconds and
episodes of torsades de pointe on the 24 hour ECG recording. The inefficacy of
beta blocker treatment alone led to the implantation of a pacemaker; no
recurrence has occurred since. The family investigation permitted to recognize
the same syndrome in his asymptomatic 8-year-old brother for whom a prophylactic
treatment was started. CONCLUSION: Both cases remind us of the necessity to carry
out systematically an ECG in every child seen for unexplained malaise related or
not to stress or for an atypical epileptic crisis. This is the only way for an
early diagnosis on which the entire prognosis depends.
PMID- 9759275
TI - [Severe streptococcal group A infection complicating varicella].
AB - Varicella is a common viral infection which is generally benign in infancy and
has a good outcome. It may sometimes be complicated by severe group A
streptococcal superinfection. CASE REPORT: Three days after the beginning of
varicella, a previously healthy 2-year-old girl presented with left leg pain,
lameness and edema of all four limbs. Toxic shock syndrome occurred, due to beta
hemolytic group A Streptococcus grown from blood culture. Computerized tomography
(CT) scan showed a mild effusion involving both hips. Cefotaxim was administered,
but the week after magnetic resonance imaging (MRI) showed a necrotizing
fasciitis and a lesion of the left leg leading to a patchy femoral diaphysis
consistent with osteomyelitis. Joint aspirate culture did not grow. The left leg
was immobilized in plaster for 6 weeks and the child was given cefotaxim and
fosfomycin parenterally during 30 days, then followed by 45 days of oral
amoxicillin. She recovered without sequelae. CONCLUSION: Group A Streptococcus
infection is a dangerous complication of varicella. It must be considered in case
of any joint pain occurring during or just after this disease. The choice of the
best treatment needs full collaboration between surgeons, radiologists and
pediatricians.
PMID- 9759276
TI - [Clear cell meningioma: recurrent intraspinal tumor in a child].
AB - BACKGROUND: Meningiomas represent 1.5% to 4.3% of cerebral and medullar primary
tumors in children. CASE REPORT: A 9-year-old girl had a history of thoracolumbar
scoliosis. An intracanalar and extramedullar tumor was confined to the lumbar
region. Resection identified a clear cell meningioma. A symptomatic and tumoral
recurrence occurred 5 months later in the same region. After a second resection,
the patient received radiotherapy. At 8 months follow-up, no recurrence was
documented. CONCLUSIONS: A stiff and painful scoliosis can be predictive of
expansive intracanalar tumor. The recurrent or multifocal evolution of clear cell
meningioma show the "aggressive behavior" of this histological type. A preventive
radiotherapy could be proposed, depending on the age of the patient and the
localization of the tumor.
PMID- 9759277
TI - [Protein and energy needs of the infant with severe malnutrition. Application in
a hospital environment for the treatment of malnutrition caused by deficient
intake].
AB - Severe malnutrition is defined by a weight for height below 70% of international
standards or by presence of oedema in a clinically undernourished child. Severe
malnutrition associated with oedema is called kwashiorkor. The origin of oedemas
of kwashiorkor is still debated, but its relation with protein deficiency is
strongly questioned. The same dietary management is now recommended for
malnutrition with or without oedema. Present recommendations are based, as for
well nourished children, on the separate estimation of nutritional requirements
for maintenance and growth. Total requirements vary between 0.7 g/kg/day in the
first few days of treatment to 5 g/kg/day or more when weight gain is maximum. As
a result of high energy requirement during catch-up growth, protein requirements
never exceed 10 to 12% of total energy needs.
PMID- 9759278
TI - [Intracranial hypertension in the infant: from its physiopathology to its
therapeutic management].
AB - The pathophysiology of elevated intracranial pressure (ICP) is assessed from a
three cerebral compartment model and from brain compliance. The mechanisms
leading to elevated ICP (expanding process, cerebral edema, brain swelling,
hydrocephalus) and their consequences (brain herniation, ischemia-anoxia
phenomenon, Cushing reaction and neurogenic pulmonary edema) are overviewed. The
causes of elevated ICP in children are reported with emphasis on traumatology.
Diagnostic procedures include clinical assessment, fundoscopy, cerebral
computerized tomography scan and specific problems of cerebrospinal fluid
investigation. Methods and results of intracranial pressure monitoring are
reported. The treatment of elevated ICP is based upon clinical follow-up and
monitoring of ICP. General therapeutic rules consist of adequate position,
suppression of any neck, skull and abdominal compression, stimuli limitation and
fluid restriction. Specific treatments include mechanical ventilation, sedation
and analgesia, barbiturates, anticonvulsant drugs, mannitol, corticosteroids,
hypothermia, enteral nutrition, and antibiotics.
PMID- 9759279
TI - [Radiologic case of the month. Torsion of the transverse colon].
PMID- 9759280
TI - [Prevention of infective endocarditis in the child. Current status and
protocols].
AB - Infective endocarditis remains a severe, potentially lethal disease, which
justifies a rigorous prevention schedule. Children with cyanotic congenital heart
disease, mitroaortic valvulopathies, prosthetic valve and uncorrected ventricular
septal defect are the most susceptible. Dental care is the main cause of
bacterial graft, followed by upper respiratory tract and cutaneous infections.
Prevention is mainly based upon antibiotic prophylaxis but patient education and
good dental hygiene are also important.
PMID- 9759281
TI - [Why pediatric consultations increase in the centers for the socially excluded?].
AB - Studies done by Medecins du Monde indicate that sanitary exclusion is a growing
phenomenon in France, children included. Paediatricians must be concerned by this
phenomenon, which is related to the social precarity of many families who do not
use the standard health care structure. They must understand the reasoning behind
the choices of these families, and be involved in the care of their children in
places that they accept to visit. Paediatricians should also be present in
institutions, conferences and debates where public health policy is discussed in
order to defend the place of paediatrics in the sanitary organisation.
PMID- 9759282
TI - [Hematuria in the child. Investigation plan in pediatric practice].
AB - The discovery of hematuria in a child should lead the pediatrician to a
methodical evaluation of the patient based on an extensive history and
comprehensive physical examination. The microscopic examination of the urine is
the cornerstone in the evaluation process and may suggest the origin of the
hematuria. For instance, red blood cell casts indicate glomerular lesions and
rule out the need for further urological examinations. According to the type of
hematuria and the associated symptoms, a complete and immediate evaluation is
sometimes necessary. This article presents a decisional tree to help the
pediatrician to investigate an hematuria and to refer the child to a specialist,
when needed.
PMID- 9759283
TI - [Syncytial respiratory virus infections and ribavirin].
PMID- 9759284
TI - [Clinical study of growth and puberty in girls in a school environment in Dakar.
Survey on 722 cases].
PMID- 9759285
TI - [Convulsive crisis and methemoglobinemia after the application of anesthetic
cream].
PMID- 9759286
TI - [Human science contribution in pediatrics].
PMID- 9759287
TI - [Living donor kidney transplantation in the child].
PMID- 9759288
TI - [An adolescent treatment unit: development and resistance].
PMID- 9759289
TI - [Hypoplasia of the penis: etiologic diagnosis and results of treatment with
delayed-action testosterone].
AB - BACKGROUND: Results of long-term testosterone treatment of congenital hypoplasia
of the penis are sparse; the aim of this work was to evaluate these results
according to age at onset of treatment, the presence or absence of hypospadias,
and its eventual adverse effect upon growth and bone maturation. PATIENTS AND
METHODS: Sixty-six children with congenital hypoplasia of the penis, isolated (n
= 31) or associated with a hypospadias (n = 35), were evaluated between 1 day and
16 years of age. The prevalence (40% of the cases) of the different malformations
and/or syndromes associated with congenital hypoplasia and its severity were not
different whether the penis was isolated or associated with hypospadias (male
pseudohermaphroditism). The effect of the testosterone heptylate (IM) was
evaluated in 40 children treated before 10 years of age. RESULTS: The penis'
increase in length was more important in the children with isolated micropenis
(+2.1 +/- 0.8 SDS) than those with hypospadias (+1.3 +/- 1.2 SDS) but, in all
cases, its increase was better when the treatment was started during the neonatal
period, which corresponded to those with the most severe forms of micropenis. A
mean regression of the penile volume of -0.7 +/- 0.8 SDS was noticed after the
end of each stimulation. No long-term secondary effects related to treatment were
seen on later growth and bone-maturation. CONCLUSION: Penile length at the last
follow-up was not associated with total dose of testosterone but with its length
at the first evaluation time (r = 0.52; P = 0.002).
PMID- 9759290
TI - [Refractory pain in children with cancer: role of peridural analgesia].
AB - BACKGROUND: Adequate treatment of pain in children with cancer is a critical
issue, and is of equal importance as discussions concerning chemotherapy, surgery
and radiotherapy. OBJECTIVE: To evaluate the treatment of refractory pain by
peridural analgesia. METHODS: Seven children (1-15 years) with solid tumors were
treated with long term epidural analgesia for refractory pain. Catheters were
inserted in epidural space (L1-L2) and infused with sufentanil, bupivacaine and
clonidine. RESULTS: Three out of five children with good response to peridural
therapy could be discharged. A 12-month-old infant had a poor response. Treatment
was discontinued in a teenager boy because of patient refusal. The side effects
were: early catheter displacement in two patients and a bacterial contamination
in one. Serious adverse effects related to high doses of opiates were not
observed. However, toxicity of bupivacaine was observed in three patients leading
to treatment discontinuation in one. CONCLUSION: Long-term epidural analgesia
looks promising in selected children with refractory pain.
PMID- 9759291
TI - [Mortality, morbidity and short-term neurologic outcome of premature infants less
than or equal to 32 weeks gestational age in Fort-de-France CHR].
AB - The mortality and neurodevelopmental outcome of premature infants born between 25
and 33 weeks of gestational age in Fort-de-France (Martinique, French West
Indies) is reported. POPULATION: The preterm cohort included 214 infants born
during the years 1992 to 1995. RESULTS: The mortality rate during the
hospitalization was 20%, but was only 14% when the birth weight was more than
1,000 g. The main neonatal problems were: hyaline membrane disease (34%),
bronchopulmonary dysplasia (6.5%), necrotizing enterocolitis (6%),
intraventricular hemorrhage (9%) and periventricular leucomalacia (2%). Twenty
infants (13.5%) showed abnormal neurodevelopmental outcome, with only three
having major handicap. CONCLUSION: This study shows a notable improvement in the
prognosis of premature infants in Fort-de-France. Nevertheless, a strong effort
must be made in very low gestational ages and very low birth weight infants.
PMID- 9759292
TI - [Adoption and chronic hepatitis B carrier state].
AB - AIM: Because there are few adoptable children in France, parents, for the last 20
years, have turned to international adoption. Alerted by the generally poor
health of these children, we paid particular attention to their health problems
and especially to infection by hepatitis B virus (HBV). POPULATION AND METHODS:
The 60 internationally-adopted children seen from June 1993 to June 1997 were
included in this study. All had hemogram and serum iron dosage, and search for
intestinal parasites and tuberculosis was performed in each child, as were HBs
antigen and HBs antibody screening. When HBs antigen was positive, HBe antigen
and antibodies, HBV DNA and hepatitis C and delta serology were also studied.
RESULTS: Six out of the 60 children were HBV chronic carriers. The six presented
HBs antigen and five out of the six presented viral DNA. One child was co
infected with delta virus. Serum aminotransferase was normal in three children
and increased in the three others. DISCUSSION: Some internationally adopted
children are exposed to chronic infection by HBV. This concerns children coming
from countries known for the high frequency of the disease, but also children
with long stay in Eastern European nurseries. Chronic HBV carriage puts the
child, as well as the family and other children in institutions and/or schools at
risk, thus necessitating preventive measures.
PMID- 9759294
TI - [Facioscapulohumeral myopathy and germinal mosaicism].
AB - BACKGROUND: Germline mosaicism is now well known to account for recurrence of
hereditary human disorders. Facioscapulohumeral muscular dystrophy is an
autosomal dominant disorder; its locus has been identified in the telomeric
region of chromosome 4 at the q35 band. It appears to have a high rate of
mutation. CASE REPORT: A young girl had presented from childhood signs of a
severe form of facioscapulohumeral muscular dystrophy, but with no familial
history. The diagnosis was ultimately confirmed at the age of 23 years by
molecular studies evidencing the deletion. The same abnormality was sparsely
found in the child's father who appeared to harbor the mutation as a germline
mosaicism with no clinical expression. CONCLUSION: This case illustrates the
possibility of severe facioscapulohumeral muscular dystrophy and the dominant
transmission of the disorder which may be clinically occult. It underlines the
importance of molecular biology and the difficulties of genetic counselling.
PMID- 9759293
TI - [Trigonocephaly: isolated, associated and syndromic forms. Genetic study in a
series of 278 patients].
AB - From a series of 1,833 patients with craniosynostosis, 278 cases with metopic
synostosis were analysed. The prevalence of metopic synostosis was estimated in
the region of 1 in 15,000 children. PATIENTS AND METHODS: All patients with
metopic suture fusion were selected, excluding cases where additional sutures
were involved. The age at diagnosis was between 15 days and 15 years. The
diagnosis was based on clinical and radiological evaluation. The search for
associated malformations was based on clinical evaluation, CT or MRI scans, bone
X-rays and ultrasounds. If possible, a study of the karyotype was performed in
case of associated malformation. Family information was obtained through contact
with the families, generally in person or sometimes by telephone. The series was
divided into three groups: isolated trigonocephaly (group 1), trigonocephaly
associated with other malformations without any known syndrome (group 2) and well
delineated syndromes (group 3). RESULTS: There were 213 males and 65 females, a
sex ratio of 3.3. Family information was obtained from 222 probands distributed
among 216 families. There was no maternal or paternal age effect. The frequency
of twinning was 7.9%, with three concordances for metopic synostosis in three
monozygotic twin pairs. A positive family history was obtained in 13 of the 216
pedigrees, giving a 6% figure of familial cases. A vertical transmission was
observed in only one case; in all other cases, there were two affected children
with normal parents. Eleven familial cases were isolated trigonocephalies, and
two were syndromic. Nine of the 53 available karyotypes were abnormal, involving
the chromosomes 7, 9, 11 or 13. There were 208 observations in the group 1. In 53
cases (group 2), associated malformations involved mainly the heart (12 cases),
the limbs (six cases), the brain (five cases) and the genito-urinary tract (four
cases). These malformations were unique in 32 cases and multiple in 21 cases.
Some: of the observations could represent new syndromes. Seventeen syndromes
represented group 3. Nine were chromosomal syndromes. Eleven presented with
multiple malformations. An in utero exposure to valproic acid was observed in two
cases of the group 1, five cases of the group 2 and one case of the group 3.
PMID- 9759295
TI - [Secondary kidney amyloidosis and mucoviscidosis].
AB - BACKGROUND: Due to the improvement in cystic fibrosis management, life expectancy
has risen; on the other hand, longer survival has led to new complications,
including secondary renal amyloidosis, which has been so far very uncommonly
reported. CASE REPORTS: Secondary nephropathic amyloidosis was seen in two 25
year and 22-year-old adults with cystic fibrosis. Both had developed recurrent
pulmonary infections due to Pseudomonas aeruginosa over several years. One
patient died after 2 years of progressive kidney failure. CONCLUSION: Severe
renal insufficiency due to secondary amyloidosis may complicate the course of
cystic fibrosis and become the main prognosis factor in adults.
PMID- 9759296
TI - [Acute rhabdomyolysis in the child].
AB - Rhabdomyolysis results from muscular fibre lysis with release of cellular
contents (myoglobin, enzymes, electrolytes) into the plasma. Traumatic (crush
syndrome) and non-traumatic rhabdomyolysis have been mostly reported in adults.
Traumatic rhabdomyolysis are mostly due to ischemic and reperfusion injuries. Non
traumatic rhabdomyolysis include several factors: muscular compression (comas),
cytotoxic injury (infections and poisonings), ischemia (shock, cardiorespiratory
arrest) or excessive muscular activity (seizures, strenuous exercise). The main
etiologies reported in children are: anoxic-ischemic encephalopathy (including
sudden infant death and life threatening events); electrolyte disorders; severe
hyperthermia; poisonings; hereditary myopathies. Non-traumatic rhabdomyolysis
must be suspected in these circumstances, requiring blood creatinine
phosphokinase measurements. Indeed, clinical signs are inconstant and non
specific, and functional signs are difficult to appreciate in children. During
the initial phase, the main risk is arrhythmias secondary to hyperkalemia. The
two main complications are the compartmental syndrome leading to irreversible
vasculo-nervous injuries and acute renal failure. Treatment of traumatic and non
traumatic rhabdomyolysis includes correction of hyperkalemia, active fluid
loading in order to prevent acute renal failure and alkalinisation. Prognosis of
rhabdomyolysis relates to the aetiology and the presence of acute renal failure.
PMID- 9759297
TI - [Oculocutaneous albinism: clinical, historical and anthropological aspects].
AB - Albinism represents a group of inherited abnormalities of the melanin pigment
system in which the synthesis of melanin is absent or reduced, generalized
(oculocutaneous albinism) or localised (ocular albinism). Recent molecular
studies provide insight into the pathophysiological processes of pigmentation
regulation and help our understanding of the genetic heterogeneity of human
albinism. It rarely affects Europeans, frequently Africans, only a minority of
Amerindians, who nevertheless, when an ethnic group is concerned, presents one of
the highest incidence in the world. Historically, the African albinos were used
as an alibi by the European theologians to support Adam's descent of humanity and
by naturalists to affirm the alleged superiority of the white men.
Anthropological data are mainly issued from Amerindians with contradictories
attitudes towards albinos: both acceptance and rejection. Only the Kuna of Panama
have given albinos a major place in their mythology, although in reality they
frequently reject them.
PMID- 9759298
TI - [Lichenoid eruptions in the child].
AB - Lichenoid eruptions are represented by lichen planus and lichen striatus. They
are characterized clinically by a papulous eruption, and histogically by a dermal
superficial infiltrate of lymphocytic cells and a cytotoxic reaction directed
against basal keratinocytes. The main differential diagnosis is hamartoma, the
differentiation being important because of the possible association of haemartoma
with malformations.
PMID- 9759299
TI - [Acute scrotum in the child].
AB - Torsion of the spermatic cord is the most common etiology of acute scrotum in
children. Children with torsion usually present with acute scrotal pain, nausea
and vomiting, and only early surgical treatment, within 6 hours of the onset of
symptoms, may ensure the preservation of the testis. For that reason any acute
scrotal pain with edema requires urgent specialized evaluation. Other etiologies
include less severe diseases as torsion of an appendage, epididimytis, trauma,
and other rare conditions such as acute idiopathic scrotal edema.
PMID- 9759300
TI - [Diagnosis and treatment of vasovagal syncope in the child and adolescent].
AB - Recurrent unexplained syncope is a common and often frustrating clinical problem
in paediatrics. Over the last decade, head upright tilt table testing has emerged
as an important diagnostic method for the identification of patients whose
syncope is likely to be neurocardiogenic in origin. At the same time, tilt table
testing, by providing syncopal episodes in a controlled setting, has allowed for
a greater understanding of their physiopathology. Treatment strategies remain
controversial but beta-blocker therapy appears to be very efficient.
PMID- 9759301
TI - [Association of Guillain-Barre syndrome and mumps in a 13-month-old infant].
PMID- 9759302
TI - [Secondary fatal acute pancreatitis in ascaridiasis in a 4-year-old child].
PMID- 9759303
TI - [Spondylocostal dysplasia in Jarcho-Levin syndrome].
PMID- 9759304
TI - [Benign intracranial hypertension after treatment with pefloxacin].
PMID- 9759305
TI - [Sudden death caused by abnormal origin of the left coronary artery from the
sinus of Valsalva].
PMID- 9759306
TI - [Calcium administration in the Brazzaville child].
PMID- 9759308
TI - [Blood transfusion in very premature infants].
PMID- 9759307
TI - [Unusual mechanism in Prader-Willi syndrome: incidence in genetic counseling].
PMID- 9759309
TI - [Pediatric survey of perinatal care networks in France].
PMID- 9759311
TI - [Urinary tract infection in ambulatory pediatrics].
AB - A survey by questionnaire on urinary tract infection (UTI) in children was
conducted over a 1-year period among paediatrician practitioners (April 1997
March 1998). The aim was to provide epidemiological data and to describe the
current therapeutic attitude on UTI in children in paediatrician practice. The
preliminary results will be presented during the meeting on UTI in children.
PMID- 9759312
TI - [Current definition of urinary tract infection in the child].
AB - Urinary tract infections (UTI) encompass a spectrum of clinical and pathological
conditions involving various parts of the urinary tract. Differentiating the
syndromes associated with UTI has important implications for treatment and
prognosis. To effectively communicate information on the subject, terminology
should be standardized and precise--a challenge as it is difficult to strictly
adapt the terms into French and subsequently apply them to practice.
PMID- 9759313
TI - [Urinary tract infection in the newborn infant].
AB - Urinary tract infection in the first month of life may be revealed by isolated
fever, poor weight gain or severe sepsis. It is more frequent in male infants.
Escherichia coli is the most common infecting agent. A urinary tract malformation
is found in approximately 30% of the cases. In most cases intravenous treatment
with an association of cephalosporin and aminoside is efficient. However, because
of the possible involvement of an enterococcus, amoxicillin must be added until
the result of the urine culture is available. Prophylaxis with oral
administration of antibiotics is recommended in case of urinary tract
malformation.
PMID- 9759314
TI - [Microbiological diagnosis of urinary tract infections in the child. Importance
of rapid tests].
AB - Urine collection study is one of the most common means of bacteriological
diagnosis in the laboratory. However, numerous interpretation problems exist. The
aim of this paper is to specify these problems and to indicate the place of rapid
tests in the screening for urinary tract infection. Direct examination must be
performed on rapidly collected and transported urine. In such conditions, absence
or presence of both leukocytes or germs presents a good negative or positive
predictive value. However, false positive leukocyturia is frequent. False
positive bacteriuria is mostly due to bad collection or transport. In some cases
the threshold of bacteriuria > or = 10(5) cfu/mL can be reduced. Rapid tests
include leukocyte esterase and nitrite tests. In our study, recording 289 tests,
we observed negative and positive predictive values of respectively, 92% and 100%
when the two tests were used together. Dipsticks can be used to exclude a urinary
tract infection when clinical symptoms are absent, but only if they are used
correctly. When both tests are positive, a urinary tract infection is likely.
Study on urine collection is difficult in children. Collaboration between
clinician and bacteriologist is essential.
PMID- 9759315
TI - [Antibiotic sensitivity to isolated bacteria in pediatric urinary tract
infections].
AB - Of the childhood urinary tract infections, more than 50% are caused by
Escherichia coli (E Coli), followed by Proteus mirabilis (P mirabilis),
Klebsiella sp, other enterobacteria, enterococci, Pseudomonas aeruginosa, and
staphylococci. Of E coli isolates, 50 to 60% are resistant to ampicillin (ampi
R), 10% being susceptible to amoxicillin + clavulanic acid (AMC). For P
mirabilis, ampi-R isolates are less frequent and more often susceptible to AMC.
Klebsiella sp is resistant to ampicillin, 75% of isolates being susceptible to
AMC. In these three species, the susceptibility of isolates to third generation
cephalosporins, aminogly-cosides, and ciprofloxacin is still high (> 90%), but 15
to 35% are resistant to cotrimoxazole. In the other enterobacteria (Enterobacter
cloacae, Morganella morganii, P vulgaris, Citrobacter freundii and Serratia
marcescens) the resistance to cefalotin (hence to ampicillin and AMC) is
permanent, with an exception: the susceptibility of P vulgaris to AMC.
Enterococci are mostly susceptible to ampicillin, and P aeruginosa to
ceftazidime, but in both species, the percentage of resistant strains in
hospitalised patients is greater than in outpatients. For Staphylococcus aureus,
the community-acquired isolates are susceptible to oxacillin and other anti
staphylococcal agents. All the coagulase negative staphylococci isolates are
susceptible to vancomycin, but 70% of those from hospitalised patients are
resistant to oxacillin, aminoglycosides and cotrimoxazole.
PMID- 9759316
TI - [Urinary tract infection and biological markers: C-reactive protein, interleukins
and procalcitonin].
AB - Serum C reactive protein (CRP) remains a good marker of the severity of urinary
tract infections in children, despite false negative results. Serum IL-6 is not a
better marker; urinary IL-6 might have a better prognostic value as it is higher
in patients with renal lesions due to infection, but low values are found in some
cases. Serum procalcitonin levels are correlated with the importance of renal
scars at scintigraphy, with less than 10% of false negative results. Further
studies are needed to confirm the sensitivity and sensibility of these markers,
especially for procalcitonin.
PMID- 9759317
TI - [Nosocomial urinary tract infections: retrospective study in a pediatric
hospital].
AB - Urinary tract infections (UTI) are the most frequent nosocomial infection in the
adult, yet very few data are available concerning these infections in children.
In a retrospective 1-year study in a paediatric hospital, we analysed the
incidence of nosocomial UTI and the characteristics of the affected children. The
incidence was of 1.97/1,000 admissions which represented 6.8% of all UTI
diagnosed by the microbiology laboratory. Most cases were in surgery and
neurology wards. The frequency was inversely proportional to the age, with 50% of
children being less than 2 years old. Pathogens most frequently isolated were E
coli (39%), Pseudomonas sp (12.1%) and Enterococcus sp (12.1%). When compared
with the organisms found in all the urine cultures during the same period, two
organisms were more frequently found in nosocomial urinary tract infections:
Pseudomonas sp and Candida sp. Most patients presented one or more risk factors,
mainly:bladder catheterisation (41.4%), prior antibiotic therapy (62%), cerebral
palsy (6.9%). No bacteriema was observed. The diagnosis of nosocomial UTI must be
interpreted with caution and needs close collaboration between microbiologists
and paediatricians. These infections increase the cost of hospitalisation, but
only exceptionally do they present with complications. Some risk factors are
inherent in hospital conditions, but others can be reduced by improving hand
washing or by changing catheterisation practices.
PMID- 9759319
TI - [Initial imaging in pediatric urinary tract infection].
AB - First step imaging investigations in urinary tract infections in children rely
upon conventional sonography, and, when available. Power Doppler sonography.
Enhanced computerised tomography (CT) and dimercaptosuccinic acid (DMSA)
scintigraphy are complementary investigations in difficult cases. Contrast
cystourethrogram has always to be performed. Intravenous pyelography is no longer
used as a first step imaging technique.
PMID- 9759318
TI - [Escherichia coli virulence factors in pediatric urinary tract infections].
AB - As many as 90% of all community-acquired urinary tract infections (UTIs) and more
than 30% of nosocomially acquired UTIs are caused by E coli. The migration of
bacteria into proximal urethra and bladder mucosa requires that the organisms
travel "upstream" and resist being carried away by the flow of urine.
Colonisation requires binding of specific adhesions of the bacteria to
appropriate receptors on the surfaces of the epithelial cells. P fimbrae are
found in 80%, 30% and 20% of strains from patients with pyelonephritis, cystitis
and asymptomatic bacteriura, respectively. P fimbrae are found in only 30% of
strains isolated from patients with pyelonephritis associated with compromising
host factors such as vesicoureteral reflux, urinary tract anatomical
abnormalities and recent urinary tract instrumentation.
PMID- 9759320
TI - [Role of DMSA scintigraphy in managing pediatric pyelonephritis].
AB - Pyelonephritis in children may lead to irreversible renal damage and eventually
to arterial hypertension and renal insufficiency. Inflammation plays a central
role in the pathogenesis of pyelonephritis. Dimercaptosuccinic acid (DMSA)
scintigraphy permits detection of acute renal lesions and renal scars with high
sensitivity and specificity. In our experience 60% of patients who had acute
renal lesions on DMSA scintigraphy during pyelonephritis develop scars. Young age
appears to be not a risk factor, as in our experience 70% of children older than
5 years develop scars compared to 40% for children younger than 1 year. In
addition, only 40% of patients who develop scars have vesicoureteral reflux. DMSA
scintigraphy may provide answers to important clinical questions: what is the
optimal length of treatment of pyelonephritis? Is parenteral treatment necessary?
What is the best treatment of vesicoureteral reflux? DMSA scintigraphy permits
therapeutical decision-making according to the renal involvement in each of our
patients.
PMID- 9759321
TI - [Parenchymatous cicatrix and urinary tract infection: physiopathology and
clinical implications].
AB - Renal scarring is the main long term complication of acute pyelonephritis in
children. The prevalence rate is hazardous since data from the literature are
confusing with respect to reflux nephropathy, chronic pyelonephritis and renal
hypoplasia. The pathology of such lesions consists in focal interstitial
fibrosis. When the first pyelonephritic attack occurs during infancy, renal
growth may be compromised. The current approach of renal scar assessment is based
on dimercaptosuccinic acid (DMSA) scan. Bilateral extensive lesions may be
responsible for altered glomerular filtration rate (GFR) and/or arterial
hypertension. The management of overt scarring is conservative and careful
prevention must be based on early and aggressive treatment of acute
pyelonephritis.
PMID- 9759323
TI - [Curative treatment of lower urinary tract infections].
AB - Because it is limited to the bladder, infection of the lower urinary tract does
not lead to renal scaring. It may be symptomatic or asymptomatic. When
symptomatic it never includes high fever and general symptoms. Only symptomatic
infections need treatment using oral antimicrobial monotherapy for 5 to 7 days.
It is necessary to search for a predisposing factor--mainly bladder dysfunction
and constipation.
PMID- 9759322
TI - [Antibiotic treatment of acute pyelonephritis in the child].
AB - Antimicrobial therapy for pyelonephritis in children must quickly eradicate the
bacterial infection and prevent scars in renal parenchyma. Escherichia coli (E
Coli) is found in about 90% of cases of acute pyelonephritis in outpatients, 40%
of E coli being ampicillin-resistant. The present effective antibiotics are: 3rd
generation cephalosporines, amoxicillin-clavulanic acid association, and
aminoglycosides. In the literature therapeutical guides are divergent concerning
the route of administration (oral or i.v.), mono or bitherapy, the duration of
the treatment (usually for 10 days), and the need for hospitalisation. The
criteria for choice are risk factors such as: very young age (< 6 months), fever
with toxic symptoms, vomiting, dehydration, uropathy, and poor compliance. There
are few long term studies which compare two, therapeutic regimens and no
evaluation of the frequency of consequent chronic pyelonephritis in adult age has
taken place. Recent data suggest that an oral sequential treatment may permit a
shorter hospital stage. The trend is chiefly to do bona fide recommendations more
than elaboration of a true consensus.
PMID- 9759324
TI - [Treatment of urinary tract infections in neurogenic bladder].
AB - Urinary tract infections are frequent in children with neurologic bladder.
Treatment must be adapted to the type of infection: acute pyelonephritis requires
early intravenous treatment: symptomatic infection of the lower urinary tract is
to be treated by oral monotherapy; asymptomatic infection needs no treatment.
PMID- 9759325
TI - [Preventive treatment of urinary tract infections in the child].
AB - Most of childhood urinary tract infections come through ascending way. Fecal
microflora is the usual source of the bacterial strains. Infection facilitating
factors are bacterial virulence which increase bacterial attachment to the
urinary tract, adhesins and toxins, mostly studied in Escherichia coli, and host
factors (receptors availability, acquired or congenital urinary tract
abnormalities). Prophylactic treatment in childhood urinary tract infection is
indicated in case of obstructed uropathy before surgery, vesico-ureteral reflux
without surgical management, recurrent cystitis. It includes hygiene, treatment
of a possible uninhibited bladder, and antimicrobial prophylaxy. Few
antimicrobial agents have been studied for efficiency and long term tolerance in
children. Nitrofurantoin and cotrimoxazole are the most currently used.
Subinhibitory concentrations, about 20% of the curative treatment dosage of lower
urinary tract infection are effective on bacterial attachment and lessen the
frequency of infections. They can be given once a day in the evening.
PMID- 9759326
TI - A genetic switch for long-term memory.
AB - Current models of brain function hold that learning corresponds to changes in the
efficacy of single synapses. The study of learning and of a variety of forms of
synaptic plasticity has revealed that both have at least two phases: an early
phase that is not dependent on protein synthesis and a late phase that depends on
new transcription and translation. Our laboratory has examined synaptic
plasticity in Aplysia and in mice to better understand the regulatory events that
lead to the induction of the late, protein synthesis-dependent phase of synaptic
plasticity. Our recent studies of Aplysia have revealed that the genes that
control the late phase of synaptic facilitation are controlled by both an
activator, ApCREB1, and a repressor, ApCREB2. This leads to a model in which the
late phase of synaptic facilitation is initiated by a perturbation of the balance
between activators and repressors of transcription; this perturbation can be
accomplished by regulating the activator, the repressor, or both. We, and others,
have shown that this transcriptional switch is conserved, at least in part, in
the regulation of synaptic plasticity in mice: CREB is implicated in activation
of genes required for LTP, a model for synaptic plasticity in the mammalian
hippocampus. We speculate that a similar balance between activators and
repressors may regulate the genes required for long-term memory in mammals.
PMID- 9759327
TI - A molecular biological approach to synaptic plasticity and learning.
AB - Until the more recent advances made in molecular biology, attempts to link
synaptic plasticity and learning have focused on using LTP as a marker of
learning-induced synaptic plasticity, where one has expected to observe the same
magnitude of change in synaptic strength as that observed with artificial
stimulation. To a large extent this approach has been frustrated by the fact that
it is generally assumed that the representation of the memory traces is
distributed throughout widespread networks of cells. By implication it is more
likely that one would observe small distributed changes within a network; a
formidable task to measure. In this review we describe how the advances in
molecular biology give us both the tools to investigate the mechanisms of
synaptic plasticity and to apply these to investigations of the underlying
mechanisms in learning and the formation of memories that have until now remained
out of our grasp.
PMID- 9759328
TI - [Brief history of long-term synaptic depression of the cerebellum].
PMID- 9759329
TI - [Long-term depression of excitatory synapses in the cortex and hippocampus].
AB - The efficacy of excitatory synapses terminating on cortical and hippocampal
pyramidal cells may be persistently depressed as well as potentiated. Homo
synaptic long-term depression (LTD) seems to be triggered by an entry of calcium
into a post-synaptic cell less than that needed to initiate long-term
potentiation (LTP). Theoretical work predicted, and experimental studies
confirmed, that moderate elevations of calcium initiate LTD via a cascade of
biochemical interactions involving calcium-dependent phosphatases. Genetically
modified animals confirmed the prediction of a sliding threshold that defines the
limit between LTD and LTP. While mechanisms for the initiation of LTD are quite
well established, it remains unclear whether pre- or post-synaptic mechanisms, or
both, are involved in its maintenance. A role for LTD in processes of learning
and forgetting in the adult animal remains to be firmly established. It seems
probable, however, that a persistent reduction in synaptic weight is a basic
process used in the establishment and refinement of neuronal circuits during
development.
PMID- 9759330
TI - Quantal analysis and long-term potentiation.
AB - Quantal analysis is useful for assessing the pre- and/or post-synaptic locus of
the expression of long-term tetanic potentiation with the condition, however,
that the studied synaptic potentials have been evoked by single cell
stimulations, as is the case with paired recordings of identified neurons. The
application of this methodology, primarily with indirect criteria, has produced
conclusions which dance back and forth across the synaptic cleft.
PMID- 9759332
TI - [Post-lesional plasticity of somatosensory cortex maps: a review].
PMID- 9759331
TI - Quantal analysis of synaptic processes in the neocortex.
AB - The application of fluctuation analysis to studies of synaptic function in the
neocortex is discussed. Analysis of failures of transmission has been valuable in
indicating whether a presynaptic or a postsynaptic site is responsible for a
change in synaptic efficacy. When combined with detailed ultrastructural
verification of all synapses involved in an individual cell to cell connection, a
reasonable estimate of quantal size and release probability under conditions of
low frequency activity can be obtained. However, both the number of available
release sites in functional terms and the probability that an action potential
(AP) will release transmitter from any given site can vary from AP to AP at
higher frequencies. A variety of presynaptic mechanisms that modulate release are
now apparent. For example, one mechanism dominates release patterns at one class
of connection which is insensitive to absolute firing frequency, but responsive
to changes in frequency. At another class of connection, a different mechanism
dominates, resulting in high sensitivity to frequency.
PMID- 9759333
TI - Memory systems.
AB - Two recent findings are summarized here that bear on the organization of memory
and brain systems. First, the capacity for simple recognition of familiarity (a
form of declarative memory) depends on the hippocampal region in both humans and
nonhuman primates. Second, probabilistic classification learning (a form of
nondeclarative memory akin to habit learning) depends on the caudate nucleus and
putamen. These findings are related to the classification of long-term memory and
current understanding of the participating brain systems.
PMID- 9759334
TI - [Olfactory training: memory systems in the rats].
PMID- 9759335
TI - [Memory consolidation and the hippocampal system].
PMID- 9759336
TI - Working memory.
AB - It is suggested that working memory comprises a system for the temporary storage
and manipulation of information, forming an important link between perception and
controlled action. Evidence is presented for a three-component model, comprising
an attentional control system, the central executive, and two subsidiary slave
systems. One of these the, the visuo-spatial sketch pad holds and manipulates
spatial information, while the other, the phonological loop performs a similar
function for auditory and speech-based information. Evidence is presented for the
view that the phonological loop has evolved as a mechanism to facilitate the
acquisition of language.
PMID- 9759337
TI - The relationships between working memory and long-term memory.
AB - Recent studies have led to the proposal that working memory operates not as a
gateway between sensory input and long-term memory but as a workspace. The core
of argument is that access to acquired knowledge and prior learning occurs before
information becomes available to working memory. This proposition is a way to
accommodate Baddeley's multiple component working memory model and the view that
considers that working memory is nothing other than temporary activations of
representations and procedures in long-term memory. However, this 'workspace'
conception of working memory raises the question of the relationships between the
central executive system and long-term memory.
PMID- 9759338
TI - The associative parietal cortex and spatial processing in rodents.
AB - It is widely acknowledged that the hippocampal formation has a central function
in rodents' spatial memory and navigation. However, recent work has shown that
other structures participate in specific spatial processing. That is so for the
associative parietal cortex (APC). Although this neocortical region is far less
developed in rodents than in humans and non-human primates, APC damage in rodents
induces deficits which affect both egocentrically and allocentrically organized
spatial behaviours. On the basis of behavioural (following parietal lesions) and
neuroanatomical data, we propose that the APC could be at the interface between
the level of perception of the physical world (egocentrically organized) and that
of representations or maps (allocentrically organized) of this world.
Reciprocally, the APC could also be involved in the transformation, in the
opposite direction, of computations made on the basis of representations into
motor actions necessary for the efficient execution of oriented behaviours within
the physical world.
PMID- 9759339
TI - Backward signal from medial temporal lobe in neural circuit reorganization of
primate inferotemporal cortex.
AB - Neuropsychological theories proposed a critical role of the interaction between
the medial temporal lobe and neocortex in the formation of long-term memory for
facts and events, which has often been tested by learning of a series of paired
words or figures in humans. We identify neural mechanisms of this long-term
memory formation process by single-unit recording and molecular biological
methods in an animal model of visual pair-association task in monkeys. In our
previous studies, we found a group of neurons that manifested selective responses
to both of the paired associates (pair-coding neuron) in the anterior inferior
temporal (IT) cortex. It provides strong evidence that single IT neurons acquire
the response-selectivity through associative learning, and suggests that the
reorganized neural circuits for the pair-coding neurons serve as the memory
engram of the pair-association learning. In this article, we investigated further
mechanisms of the neural circuit reorganization. First, we tested the role of the
backward connections from the medial temporal lobe to IT cortex. Ibotenic acid
was injected unilaterally into the entorhinal and perirhinal cortex which
provided massive backward projections ipsilaterally to IT cortex. We found that
the limbic lesion disrupted the associative code of the IT neurons between the
paired associates, without impairing the visual response to each stimulus.
Second, we ask why the limbic-neocortical interactions are so important. We
hypothesize that limbic neurons would undergo rapid modification of synaptic
connectivity and provide backward signals that guide reorganization of
neocortical neural circuits. We then investigated the molecular basis of such
rapid synaptic modifiability by detecting the expression of immediate-early
genes. We found strong expression of zif268 during the learning of a new set of
paired associates, most intensively in area 36 of the perirhinal cortex. All
these results with visual pair-association task support our hypothesis, and
demonstrate that the 'consolidation' process, which was first proposed on the
basis of clinico-psychological evidence, can now be examined in the primate with
neurophysiolocical and molecular biological approaches.
PMID- 9759340
TI - Learning by neurones: role of attention, reinforcement and behaviour.
AB - The importance of the behavioural situation, attentional demands of the task, and
stimulus-reinforcement contingencies in promoting or permitting experience
dependent neuronal plasticity is argued. Evidence is provided for the specific
activation of the locus coeruleus noradrenergic system of the rat by novel
stimuli encountered while investigating the environment, as well as during a
formal learning situation. Noradrenergic neurons are particularly concerned with
changes in the predictive value of the stimulus, when new learning should occur.
Noradrenaline, released at LC terminals in target sensory systems, could
facilitate shifts in attention, information processing and memory through its
well-documented gating and tuning effects and its permissive role in long-term
potentiation. Dopamine neurons, which fire persistently to reward during
learning, could be involved in maintaining the behavioural response.
PMID- 9759341
TI - Brain imaging and memory systems in humans: the contribution of PET methods.
AB - The development of neuroimaging methods such as PET, has provided a new impulse
to the study of the neural basis of cognitive functions, and has extended the
field of inquiry from the analysis of the consequences of brain lesions to the
functional investigations of brain activity, either in patients with selective
neuropsychological deficits or in normal subjects engaged in cognitive tasks.
Specific patterns of hypometabolism in neurological patients are associated with
different profiles of memory deficits. [18F]FDG PET studies have confirmed the
association of episodic memory with the structures of Papez's circuit and have
shown correlations between short-term and semantic memory and the language areas.
The identification of anatomo-functional networks involved in specific components
of memory function in normal subjects is the aim of several PET activation
studies. The results are in agreement with 'neural network' models of the neural
basis of memory, as complex functions subserved by multiple interconnected
cortical and subcortical structures.
PMID- 9759342
TI - Is PET solely a post-hoc tool to validate psychological models of memory?
PMID- 9759343
TI - The pharmacology of memory.
AB - Neurotransmitters play a critical role in the brain circuits involved in various
aspects of memory. The importance of acetylcholine is illustrated by the
psychopathology of Alzheimer's disease. Cholinergic replacement therapy is now
available for treating the cognitive decline associated with this form of
degenerative disease. Dopamine in the prefrontal cortex also contributes to
information storage, particularly working memory. In both cases efforts have been
made to identify the receptor subtype involved and such information is essential
if pharmacologically specific drugs are to be developed for cognitive
enhancement.
PMID- 9759344
TI - 5-HT4 receptors: long-term blockade of K+ channels and effects on olfactory
memory.
PMID- 9759345
TI - [The decrease in the hippocampus of the neurosteroid pregnenolone sulfate is
involved in memory deficit in the aged animal].
PMID- 9759347
TI - [For a "neurocognitive" approach to memory: value of neuropsychology].
AB - Cognitive models suggest that memory consists of potentially independent modules.
In addition, clinical data lead to a reference to the central systems that
interact with these operative modules, and which assign significance and
pertinence to the information being processed. Such an organization fits better
with clinical data, since it can be demonstrated with the example of episodic or
procedural memories as both require the activation of strategic processes, under
the control of the prefrontal cortex, needed for the organization or the control
of the information to be processed.
PMID- 9759346
TI - [Memory disorders: from lesional deficit to functional disorders].
AB - The purpose of this presentation of pathological data is to demonstrate how our
ideas have developed from a chronological point of view to our present interest
in elementary cognitive processes. The present relative rarity of significant
data in brain imagery, compared with what is observed in other fields of neuro
psychology, is probably due to the complexity of this cognitive processes.
PMID- 9759348
TI - Hierarchical neuronal modeling of cognitive functions: from synaptic transmission
to the Tower of London.
AB - Recent progress in the molecular biology of synaptic transmission, in particular
of neurotransmitter receptors, offers novel information relevant to 'realistic'
modeling of neural processes at the single cell and network level. Sophisticated
computer analyses of 2D crystals by high resolution electron microscopy yield
images of single neurotransmitter receptor molecules with tentative
identifications of ligand binding sites and of conformational transitions. The
dynamics of conformational changes can be accounted for by a 'multistate
allosteric network' model. Allosteric receptors also possess the structural and
functional properties required to serve as coincidence detectors between pre- and
post-synaptic signals and, therefore, can be used as building blocks for a
chemical Hebb synapse. These properties were introduced into networks of formal
neurons capable of producing and detecting temporal sequences. In more elaborate
models of pre-frontal cortex functions, allosteric receptors control the
selection of transient 'pre-representations' and their stabilization by external
or internal reward signals. We apply this scheme to Shallice's Tower of London
test, and we show how a hierarchical neuronal architecture can implement
executive or planning functions associated with frontal areas.
PMID- 9759350
TI - Memory, learning and metacognition.
PMID- 9759349
TI - Modeling memory: what do we learn from attractor neural networks?
AB - In this paper we summarize some of the main contributions of models of recurrent
neural networks with associative memory properties. We compare the behavior of
these attractor neural networks with empirical data from both physiology and
psychology. This type of network could be used in models with more complex
functions.
PMID- 9759351
TI - Accelerated cyclization of lambda DNA.
AB - In the presence of spermidine, the DNA molecule of the bacteriophage lambda
undergoes a coil-globule transition. We report here that the cyclization of this
molecule in its globular state is greatly accelerated (by more than 10(4)-fold)
in comparison with the cyclization reaction taking place in the coil
conformation.
PMID- 9759352
TI - [Effect of halogenated quaternary ammonium on cultured tumor cells].
AB - This work reports the action of one halogenic quaternary ammonium compound on the
in-vitro proliferation of different lines of human cancer cells. IC 50 inhibition
growth was observed at a concentration of 2.10(-6) mol and T1 growth at 3.10(-6)
5.10(-5) mol. These results seem to indicate that halogenic quaternary ammoniums
present a potent growth inhibitory activity on different cancer cells lines. The
presence of a quaternary ammonium group, responsible for some alkylating effect,
could explain such a result.
PMID- 9759353
TI - Atypical microtubule organization in undifferentiated human colon cancer cells.
AB - We previously reported that undifferentiated colonic cancer HT-29 cells, unlike
the differentiated ones, exhibit unusual organelle distributions and atypical
vesicle trafficking patterns, which are microtubule-independent and microfilament
dependent. In the present study, we have analyzed the microtubule network in both
phenotypes, using confocal microscopy, and determined the expression levels of
some microtubule-associated proteins by quantitative immunoblotting.
Differentiated cells exhibited the microtubular organization of polarized
epithelial cells. Non-polarized undifferentiated cells presented an atypical
microtubule organization as microtubules were localized mainly at the cell 'top'.
Immunoblot analysis indicated the absence or low content of several structural
and motor microtubule-associated proteins in undifferentiated cells, compared to
differentiated cells. This may explain in part their atypical microtubular
organization. This study agrees with a crucial role for microfilaments in the
intracellular organization of undifferentiated HT-29 cancer cells, while
differentiated HT-29 cells exhibit intracellular organization similar to that of
normal enterocytic cells, although they are also tumoral.
PMID- 9759354
TI - An accessory peptide binding site with allosteric effect on the formation of
peptide-MHC-II complexes?
AB - MHC-II molecules bind a single peptide in their groove. Here, the authors
summarise evidence that a second peptide could bind transiently to MHC-II
molecules outside the groove and have an allosteric effect on peptide-MHC-II
complex formation. This effect could modulate, after the antigen processing, the
selection of the peptide subset presented by MHC-II molecules to the helper CD4 T
cells, which regulate the specific immune response.
PMID- 9759355
TI - High protection by grape seed proanthocyanidins (GSPC) of polyunsaturated fatty
acids against UV-C induced peroxidation.
AB - The antioxidative effects of grape seed proanthocyanidins (GSPC) were studied in
three in-vitro models in which polyunsaturated fatty acids (PUFAs) in aqueous
solution and mice liver or brain microsomes were used as oxidative substrates,
and UV-C irradiation as the pro-oxidant system. Analysis of UV-C induced lipid
peroxidation was carried out by two methods: gas liquid chromatography of
residual PUFAs and release of thiobarbituric acid-reactive substances (TBARs)
measured by TBA reaction. Results indicate that PUFAs are more radiosensitive
when incorporated in single component micelles than in mixed component micelles
or microsomes. In every case, PUFA peroxidation was inhibited by low
concentrations of GSPC (2 mg/L) while epigallocatecin (EGC) and epigallocatechin
gallate (EGCG) monomers, at an equivalent level of epicatechin, exhibited no
efficacy in our experimental conditions. This latter effect might be explained by
a synergistic action of flavan-3-ol monomers, dimers and oligomers contained in
the grape seed extract.
PMID- 9759356
TI - Origin and evolution of Asian hominoid primates. Paleontological data versus
molecular data.
AB - The origin and evolution of hominoid primates (apes and man) has long been
studied exclusively on the basis of available fossil remains. Indeed, a migration
of African primates towards Asia at about -16 to -17 Ma might have given the
lineage of Miocene Asian hominoids. This hypothesis is supported by the oldest
remains of Miocene Asian hominoids dated at about -16.1 Ma. But the recent
discovery of anthropoid primates in the Eocene of Asia seems to indicate that
Asia was a major evolutionary and differentiation centre for anthropoid primates
as early as the Eocene. In addition, Asian primates probably continued to evolve
in Asia from the Eocene onward and led at least to the extant Asian hominoids
(orangutans and gibbons). African and Asian extant anthropoid primates might
therefore have diverged at least 36 Ma ago, and this hypothesis is also supported
by the most recent data in molecular biology. Moreover, an Asiatic origin of
African Paleogene propliopithecine primates is suggested. In that context,
evolutionary rates might not be constant, and molecular clocks should be
necessarily characteristic for each studied group of mammals. Several examples
that illustrate the conflict between paleontological and molecular data are
discussed. The necessity to integrate more systematically paleontological data as
chronological reference points in studies in molecular phylogeny is discussed.
PMID- 9759358
TI - [Tissue selectivity of calcium channel blockers].
AB - Calcium channel blockers are also termed calcium antagonists or calcium entry
blockers. The use of calcium antagonists for the management of hypertension is
well established. Their control of vascular tone is related to their interaction
with the alpha 1 subunit of L-type calcium channels. This interaction is not
simple since prolonged depolarisation promotes the inactivated state of the
channels resulting in a change of affinity which is different for various
molecules so far considered. The isoforms of alpha 1 subunits and the duration of
the stimulus required to activate heart or vessels are important parameters to be
considered with the nature of the molecule. Those parameters influence the
vascular selectivity which is quantified as the ratio of the concentrations
required to reduce by 50% the contraction of heart and of vessels. This
selectivity is an important component in the therapeutic action. Another
component of this action is the prevention of structural changes noted in heart
and arteries. As well as lowering blood pressure, calcium channel blockers have
also been found to exert blood pressure independent effects. For instance, they
reduce cardiac and vascular hypertrophy and avoid renal damage. In the stroke
prone rat, such protective effects are accompanied by reduction of the salt
dependent overexpression of the gene of endothelin-1 and of fetal genes
associated with cardiac hypertrophy. This paper summarizes available information
about those components and discuss their significance.
PMID- 9759357
TI - [Paleogenetic analysis of the skeletons from the sepulchral cave of Elzarreko
Karbia (Bronze Age, Basque Country)].
AB - Through paleogenetic studies we have characterised the sampling of a sepulchral
cave named Elzarreko Karbia, in the Basque Country (France). Four people had been
buried in this cave in the Ancient Bronze Age, three men, including an
adolescent, and a woman, dating from 3,700 BP. In addition to a confirmation of
the anatomical sex determination through amelogenin first intron amplification,
we obtained a mitochondrial second hypervariable region (HVR II) sequence for
each individual, and thus, we excluded maternal relationship between some of the
skeletons.
PMID- 9759359
TI - [Physiopathology of calcium channels: identification of calcium channelopathies].
AB - Since a few years, many mutations in genes encoding voltage-dependent ion
channels have been identified. The related disorders are quoted as
"channelopathies". These mutations are responsible for several skeletal muscle,
brain, heart or kidney diseases. Abnormal calcium channels genes are responsible
for hypokaleamic periodic paralysis (CACNA1S) as well as some forms of ataxia,
cerebellar degeneration and migraine (CACNA1A). The preliminary studies of the
recently discovered calcium channelopathies are undergoing. Both in vitro and in
vivo studies of the diseased genes should help to the understanding of the
related pathologies as well as to extend our knowledge of calcium channel
function. In addition, autoantibodies against calcium channels are retrieved in
some autoimmune diseases, such as Lambert-Eaton myasthenic syndrome (LEMS).
Complementary studies are necessary to identify the precise implication of
calcium channels in these auto-immune channelopathies.
PMID- 9759360
TI - [Intracellular calcium channels, hormone receptors and intercellular calcium
waves].
AB - The hormone-mediated intercellular Ca2+ waves were analyzed in multiplets of rat
hepatocytes by video imaging of fura2 fluorescence. These multicellular systems
are composed of groups of several cells (doublets to quintuplets) issued from the
liver cell plate, a one cell-thick cord of about 20 hepatocytes long between
portal and centrolobular veins. When the multiplets were homogeneously bathed
with the glycogenolytic agonists vasopressin, noradrenaline, angiotensin II and
ATP, they showed highly organized Ca2+ signals. Surprisingly, for a given
agonist, the primary rises in intracellular Ca2+ concentration ([Ca2+]i)
originated invariably in the same hepatocyte, then was propagated in a sequential
manner to the nearest connected cells (cell 2, then 3, cell 4 in a quadruplet,
for example). The sequential activation of the cells appeared to be an intrinsic
property of multiplets of rat hepatocytes. The same sequence was observed at each
train of oscillations occurring between cells. The order of [Ca2+]i responses was
modified neither by repeated additions of hormones nor by the hormonal dose. The
mechanical disruption of an intermediate cell did not prevent the activation of
the next cell. These results suggest that each hepatocyte in the multiplet
displays its own sensitivity to the hormone and that a gradient of sensitivity
between each cell could be responsible for directing the intercellular Ca2+ wave.
To test this hypothesis, we selectively isolated rat hepatocytes from periportal
(PP) and perivenous (PV) areas of the liver cell plate. Periportal (PP) and
perivenous (PV) rat hepatocyte suspensions were loaded with quin2/AM and hormonal
responses were studied in a spectrofluorimeter. Noradrenaline, angiotensin II,
and vasopressin-induced [Ca2+]i rises were greater in PV than in PP hepatocytes.
In contrast, PP cells were more responsive than PV cells to ATP. The function of
the InsP3 receptor (InsP3R) was also studied by measuring the InsP3-mediated
45Ca2+ release from permeabilized PP and PV hepatocytes. In permeabilized PP and
PV hepatocytes, internal Ca2+ stores displayed the same loading-kinetics, the
responses to InsP3 were similar, and the sizes of InsP3-sensitive compartment
were not different. In a further study, we investigated by video microscopy in
fura2-loaded multicellular systems of rat hepatocytes, the mechanisms controlling
intercellular propagation of the Ca2+ wave and coordination of Ca2+ signals
induced by the different hormones. Using focal microperfusion which allows local
perfusion of any cell of the multiplet, rapid agonist removal during the Ca2+
response and microinjection, we found that second messengers and [Ca2+]i rises in
one hepatocyte cannot trigger Ca2+ responses in connected adjacent cells,
suggesting that diffusion across gap junctions, while required for coordination,
is not sufficient by itself for the propagation of the intercellular Ca2+ wave.
In addition, focal microperfusion and intermediate cell disruption experiments
revealed very fine functional differences (hormonal delay, frequency of [Ca2+]i
oscillations) between hormone-induced Ca2+ signals, even between two adjacent
connected hepatocytes. Recent unpublished results performed in suspensions of PP
and PV rat hepatocytes supported the view of a major role played by vasopressin
receptors (V1a) in genesis and orientation of the Ca2+ wave. Vasopressin binding
sites, V1a mRNAs detected by RNAse Protection Assay, and vasopressin-induced
InsP3 production, were more abundant in PV than in PP cells. A gradient of
hormone receptors could orientate the propagation of the Ca2+ wave in
multicellular systems and in liver cell plate. These results suggest that the
intercellular Ca2+ wave in multicellular systems of rat hepatocytes is propagated
through mechanisms involving at least three factors. (ABSTRACT TRUNCATED)
PMID- 9759362
TI - [Drawing movements and gravitational force: central or peripheral regulation?].
AB - Drawing arm movements in four different directions: a) upward vertical (0
degree), b) upward oblique (45 degrees), c) downward vertical (180 degrees) and
d) downward oblique (135 degrees), and at two different speeds, normal and fast,
were executed by eight subjects. Movements of the arm were recorded using an
optoelectronic (2 TV, 100 Hz) system which allowed the computer reconstruction of
joint motion. Analyses focused upon pen kinematics in the frontal plane. Velocity
profiles were unimodal for all conditions. The ratio of acceleration time to
total movement time changed significantly as a function of the direction and the
speed of the movement. Movement time and was not affected by movement direction
and consequently changes in gravitational torques, for both speeds tested.
Results from this study provide indirect evidence that the CNS executes movements
by taking advantage of gravitational force.
PMID- 9759361
TI - [Astrocytes and lentivirus infection in an experimental models of macaque
infected with SIVmac251].
AB - The present study demonstrates the susceptibility of astrocytes to infection with
SIVmac251. Indeed, primary cultures of astrocytes derived from simian adult
brains, can be infected in vitro with the SIVmac251. Results show that SIVmac251
establishes a persistent infection in primary astroglial cultures and that viral
replication can be reactivated by TNF-alpha, GM-CSF, IFN-gamma. Viral proteins as
Nef, Rev, Vpx and occasionally gp120/160 are evidenced by immunocytochemistry. In
vivo SIVmac251 and/or HIV-2 infected astrocytes have been isolated from brains of
macaques following ex vivo primary cultures. The whole of these results
demonstrated that, in this model, SIV establishes a persistent state of infection
of astrocytes, that viral replication can be reactivated by cytokines and
moreover suggest strongly an in vivo infection of astrocytes in the brain of
these infected macaques.
PMID- 9759363
TI - [Recovery of muscle contractility after a strength training session: mechanical,
neurophysiologic and biochemical approach].
AB - The purpose of this study was to observe the recovery of maximal strength
immediately after a maximal eccentric strength training set. The trained female
subjects (n = 8) performed 10 bouts of 10 maximal eccentric contractions of the
quadriceps muscle. Each bout was separated by a 2 minutes rest period. Integrated
electromyogram (iEMG) of the vastus medialis and the rectus femoris, and torque
were measured before, just after, 24 and 48 hours after training session, at
different knee angular velocity (-60, 0, 60, 120, and 240 degrees.s-1). Possible
structural damage of the muscular cell were searched from the urinary
concentration of some protein catabolism metabolites before (basal rate), 24 and
48 hours after the exercise. Maximal torque significantly fell for any angular
velocity immediately after the training session: 13.6% at -60 degrees.s-1, 16.9%
at 60 degrees.s-1, 7.5% at 120 degrees.s-1, 12.8% at 240 degrees.s-1 and 8.6% at
0 degree.s-1. This event was accompanied by an increase of the iEMG at the
training angular speed, and by an increase of the metabolites concentration in a
half part of the subjects. Strength developed during eccentric contraction showed
the earliest recovery. And it even significantly overshot its initial level by
14.9% at 48 hours. A significant increase of the iEMG assessed at the eccentric
velocity was then observed. In the same time, 3 of the 6 subjects showed an
increase of their urinary concentration of the chosen metabolites in comparison
with their initial values. This result may closely be connected with the
supercompensation phenomenon, which first appears in the training mode. This
phenomenon could partly be explained by the associated increase of the iEMG.
PMID- 9759364
TI - [Similarities between angiogenesis and neoplasm invasiveness ].
AB - We have shown that given cytokines are capable of inducing the expression of
transcription factors of the Ets family in two very distinct cell types: 1)
endothelial cells of blood vessels, but only during neovascularization, and 2)
fibrocytic cells from stroma surrounding tumors, but only if these tumors bear
characteristics of invasiveness. In such cases, the fibrocytic cells also express
some metalloproteinases (collagenase 1, urkinase plasminogen activator, sometimes
stromelysin1). In ex vivo reconstruction experiments, we demonstrate that the
corresponding genes are directly up-regulated by the Ets family transcription
factors, often associated with the transcription complex Jun/Fos. The proteinases
are thought to dismantle the stroma and allow invasive tumors to proceed toward
further expansion. We speculate that inactivation of the Ets factors could
seriously hamper both neovascularization and tumor expansion.
PMID- 9759366
TI - [The alpha-catenin gene is a suppressor gene of neoplasm invasiveness].
PMID- 9759365
TI - [Cyclin A: a good markers for the study of cell cycle control and tumor
progression?].
AB - Cyclin A is a positive regulatory component of kinases required for the
progression through S phase and for the transition between the G2 and M phases of
the cell division cycle. Previous studies conducted in established cell lines and
in primary human T lymphocytes, have demonstrated that the promoter of its gene
is under negative transcriptional control in quiescent cells. The DNA sequences
mediating this repression have been delineated through in vitro mutagenesis as
well as in vivo genomic footprinting experiments. Indirect observations suggest
the involvement of proteins related to the retinoblastoma tumor suppressor
protein (pRb). Using primary fibroblasts from either pRb(-/-), p107(-/-), p130(-/
) or p107(-/-)/p130(-/-) mice, we show in this work that mutation of the pRb gene
has the more profound effect on cyclin A transcription. Finally, normal
fibroblasts cultured in suspension fail to express cyclin A and can no longer
enter S phase and proliferate, revealing thus a dependence of cyclin A expression
on cell anchorage. Our work suggests the existence of at least two sets of
regulators controlling cell cycle progression. On the one hand, proteins like
cyclin D1, whose expression is a direct consequence of the activation of the ras
signalling pathway and on the other hand, proteins like cyclin A which are
secondary response effectors. As a result, growth factor stimulation leads to a
transcriptional activation of the former set, while the transcription of the
latter set is under the control of a repressor whose effect is alleviated after
triggering the ras cascade. The status of pRb thus dictates whether cells
continue their progression through the cell cycle when ras is mutated, probably
by allowing the uncontrolled expression of critical genes like cyclin A.
PMID- 9759367
TI - [Is hereditary predisposition to breast cancer linked to BRCA1 a disease of
response to genotoxic lesions?].
AB - Germline mutations in either the BRCA1 or the BRCA2 gene are responsible for the
majority of hereditary breast cancers. The proposition that BRCA1 may play a role
as a caretaker of the genome, was first put forward by the demonstration that, in
mitotic and meiotic cells, BRCA1 can interact with Rad51, a major actor in repair
and/or recombination processes. From there, a fair body of observations have
converged to support the concept that BRCA1 and BRCA2 play a role in monitoring
and/or repairing DNA lesions. The relaxation in this monitoring, due to mutations
of either of these two genes, leaves unrepaired events and leads to the
accumulation of mutations and ultimately to cancer. Understanding the precise
biochemical function of BRCA1 and BRCA2 should provide basis for early diagnosis
and prevention in women carrying a predisposition to breast cancer.
PMID- 9759368
TI - [Extracellular proteases of stromal origin: contribution to tumor progression and
therapeutic perspectives].
AB - For a long time, extracellular proteinases were thought to be expressed by the
cancerous cells and only able to cleave extracellular matrix components, in order
to promote tumor cell invasion. Recent works have now demonstrated that these
proteinases are currently synthesized by stromal fibroblastic cells and that some
of them may exhibit additive function(s). These findings lead to a new
therapeutical concept leading to target the activity of stromal proteinases, and
most notably of the matrix metalloproteinases.
PMID- 9759369
TI - [Oncogenic factors of metastatic dissemination in neuroblastoma].
AB - Disseminated neuroblastoma frequently show a very poor prognosis. N-myc gene
amplification, 1p deletion and lack of CD44 gene expression, are all genetic
factors associated with the disease's dissemination. Human neuroblastoma
xenografts in nude mice has permitted to characterize, in disseminated
neuroblasts, oncogenes overexpression, inactivation of tumor suppressor genes as
well as detoxifying genes activation which contributes to increase cellular
resistance to chemotherapy. These genetic abnormalities permit to propose a
nosology of this very aggressive pediatric solid tumor. Hopefully, this genetic
classification could be of great value for new therapeutic approaches.
PMID- 9759371
TI - [Clinical implications of spontaneous and iatrogenic dissemination of tumor cells
in patients with primary liver cancer].
AB - Prognosis of patients with primary liver cancer (PLC) often depends on tumor
recurrence and development of extrahepatic metastases, particularly after liver
transplantation. We have developed a sensitive test detecting both spontaneous
circulation of tumor cells and spread of liver cells due to chemoembolization and
alcoholization. By RT-PCR we looked for cells expressing alphafetoprotein (AFP)
mRNA in peripheral blood of 84 patients with PLC and 102 controls (55 patients
with chronic hepatitis and/or cirrhosis, 10 patients with benign liver tumors or
liver metastases from intestinal cancers and 37 healthy individuals). By spiking
blood of healthy volunteers with HepG2 cells we assessed the sensitivity limit:
one HepG2 cell mixed with 10(7) leucocytes. All 102 controls scored negative. In
contrast, 28 patients (33.3%) with PLC scored positive. Positivity for the test
was significantly associated with portal thrombosis, tumor size, intravascular
tumor emboli, serum AFP level and extrahepatic metastases. Patients were followed
up for a mean period of 39 +/- 51 weeks: the probability of developing
extrahepatic metastases was significantly higher in positive than in negative
patients. Eighteen negative patients with PLC were tested before, one hour and 24
hours after loco-regional therapy: 9 scored positive either one or 24 hours after
alcoholization or chemoembolization. In conclusion, we have developed a highly
specific and sensitive test to detect circulating tumor cells in patients with
PLC. This test is likely to be clinically useful to evaluate the risk of
developing extrahepatic metastases. Finally, we are developing new strategies to
characterize cells iatrogenically spread into the blood and to define their
metastatic potential.
PMID- 9759370
TI - [Arsenic and retinoic acid, toward targeted treatments of acute promyelocytic
anemia?].
AB - Acute promyelocytic leukaemia is a key model system in cancer biology. Its
exquisite sensitivity to retinoic acid constitutes the first example of
differentiation therapy. The PML/RAR alpha fusion protein generated by the t(34,
35) translocation is the molecular basis of transformation. PML/RAR alpha induces
transformation most likely through a dominant negative interference with the
function of nuclear receptors leading to a differentiation block. The fusion
protein also delocalises PML and other nuclear body antigens and this alteration
of nuclear protein traffic seems to play a role in growth control and apoptosis.
The clinical response of this disease to retinoids and arsenic trioxide, both of
which induce the degradation of the fusion protein, constitute the first example
of a therapy directly targeted to a specific genetic lesion in a human cancer.
PMID- 9759372
TI - [Polysialylated NCAM in CSF, a marker for invasive medulloblastoma].
AB - We described a double-site enzyme-linked immunosorbent assay (ELISA) to measure
polysialic acid neural cell adhesion molecule (PSA-NCAM) level in CSF.
Immunocapture of PSA-bearing molecules is first effected by means of a monoclonal
antibody (anti-MenB), directed against sialic acid polymers and adsorbed into
plastic wells. Linked PSA-NCAM is then revealed by means of a second antibody,
directed against an aminoacid sequence of NCAM and labelled with peroxydase. The
lowest amount of PSA-NCAM detectable was estimated to be 0.11 microgram/l. This
value was considered as the threshold for positivity. PSA-NCAM level was measured
using this method in CSF from 29 patients with medulloblastoma. CSF had been
collected at different times following tumor excision and stored at--80 degrees
C. At the same times, cytological examination in CSF (medulloblastoma metastatic
cells) and craniospinal imaging (tomographic scan or MRI) had been performed. PSA
NCAM was never detected in control CSF. For patients in remission, beyond the
post-operative period of 1 or 2 months, 18 on 21 exhibited a PSA-NCAM level below
the threshold value. For refractory patients, so classified according to the
positivity of cytology and/or imaging, whatever the time after the tumor
excision, PSA-NCAM was always positive (23/23), while either cytology or imaging
were positive less frequently (16/23 for both). For relapses, PSA-NCAM was more
frequently positive (6/7) than cytology and imaging (1/7 and 5/7, respectively).
We concluded that PSA-NCAM positivity in CSF may be a reliable marker to detect
the invasive or metastatic feature of medulloblastoma.
PMID- 9759373
TI - [Synthetic peptide as retinoid vector and antiproliferative agent].
AB - First part: Structure, conformational behaviour and vectorization properties of a
peptide (PFNLS) designed by association of a fusion peptide and a nuclear
localization sequence is described. Tryptophan fluorescence quenching
measurements show that ten peptide molecules bind one all trans retinol or all
trans retinoic acid molecule with a strong affinity (Kd' = 40 nM). And is able to
help the internalization of all-trans retinol in human fibroblasts.
Stoichiometry, structure and affinity of the binding can be compared with those
of cellular retinoid binding proteins (CRBP), the structure of which is an
antiparallel beta barrel. Second part: Cytotoxic properties of the amphiphilic
synthetic peptide are presented. Comparative analysis of proliferating,
differentiated and confluent H9C2 adherent cells shows a correlation between
toxicity and cell cycle stage (proliferating cells). Electrophysiological
measurements on Xenopus laevi oocytes bathed in the peptide also demonstrate the
induction of cationic currents, which are voltage dependent. These results allow
us to hypothesize that the observed toxicity is related to membrane
hyperpolarization of proliferating cells at the G1/S cell cycle phase transition.
An important point is that in the case of the "peptide-retinoid" complex, no
cytotoxicity is observed.
PMID- 9759374
TI - [Effects of HGF on the production of matrix metalloproteinases by colonic cancer
cells DHD/K12].
AB - Matrix metalloproteinases (MMPs) and growth factors such as hepatocyte growth
factor (HGF) are implicated in tumoral progression of several digestive cancers.
The rat DHD/K12 colonic cancer cell line is very invasive in vivo. We showed by
RT-PCR and western immunoblotting the presence of HGF receptor, c-Met, in DHD/K12
cells. Then, we detected by zymography and western blots the secretion of MMP-2
and MMP-9 in the conditioned medium of these cells. After 24 or 48 h of culture
in medium supplemented with HGF, transforming growth factor-alpha (TGF-alpha) or
sodium butyrate, MMP production by DHD/K12 cells was stimulated by HGF and TGF
alpha and inhibited by sodium butyrate. Knowing the capacity of MMPs to degrade
the extracellular matrix and thus to favour tumoral invasion, results suggest
that HGF is implicated in the aggressive behaviour of DHD/K12 cells since it
increased MMPs secretion by these cells.
PMID- 9759375
TI - [Mechanisms of action and cellular functions of molecular motors].
AB - Cytoskeleton based molecular motors support most of the cellular movements and by
consequence they are associated with a variety of human disorders. The wide
functional diversity of these molecular motors is now explained by the presence
of three different families: the myosin, kinesin and dynein families. Although
they are functionally distinct, these motors present unexpected structural
homologies at the ATP and actin or microtubule binding sites. However, these
homologies do not seem sufficient to design a common molecular mechanism which
allows these proteins to move along the cytoskeleton.
PMID- 9759376
TI - [Molecular dynamics of annexin I in normal and infected cells].
AB - Annexins are a family of proteins present within the tissues of all multicellular
organisms, mammalian erythrocytes excepted. The property shared by all annexins
is the calcium and membrane binding. Annexins are constituted of two domains. The
N-terminal domain gives the molecule its specificity and the C-terminal domain,
highly conserved, containing 4 repetitions of 70 amino-acids, gives the common
properties. Although numerous important works were performed, the exact function
of annexins is not unraveled. They participate to many cellular processes as for
instance exocytosis, endocytosis or phagosome maturation. Many hypotheses,
supported by experimental results, have been proposed. In this review, we propose
a summary of the principal characteristics of annexins and we discuss the main
hypotheses proposed for their functions.
PMID- 9759377
TI - [Tyrosine kinases of the Src family, enzymes with multiple functions: from the
growth of fibroblasts to the migration of epithelial cells].
AB - The tyrosine kinases of the Src family were first discovered due to their
oncogenic properties. In untransformed fibroblasts, these kinases are activated
as cells exists quiescence in response to some growth factors. Using
microinjection to introduce catalytically inactive dominant-negative form of
cSrc, as well as an antibody that neutralizes cSrc, Fyn and cYes, we have shown
that Src kinases are required for DNA synthesis induced by most growth factors
(PDGF, EGF, CSF-1, insulin, IGF-1). A functional link between Src kinases and the
expression of the transcription factor c-Myc was also shown. In addition to cell
growth promotion, some factors induce epithelial cell scattering and this also
requires cSrc and cYes activities. However, in contrast to mitogenesis, they do
not need novel gene expression for signalling but rather may act by
phosphorylating components that regulate the cytoskeleton. Finally, increased Src
kinase activities were found in several human carcinomas and we propose that
these enzymes are involved in cell invasion.
PMID- 9759378
TI - [Role of the multifunctional Trio protein in the control of the Rac1 and RhoA
gtpase signaling pathways].
AB - The small GTPases Cdc42, Rac and RhoA have important regulatory roles in
mediating cytoskeletal rearrangements, MAP kinase cascades and induction of G1
cell cycle progression. The activity of the GTPases is regulated by guanine
nucleotide exchange factors (GEFs) which accelerate their GDP/GTP exchange rate,
and thereby activate them. All the GEFs for the Rho-GTPases family share two
conserved domains: the DH domain (for Dbl-homology domain) responsible for the
enzymatic activity, and the PH domain, probably responsible for the proper
localization of the molecule. Trio is a multifunctional protein that is comprised
of two functional Rho-GEFs domains and a serine/threonine kinase domain. We have
shown in vitro and in vivo that the first GEF domain (GEFD1) activates Rac1,
while the second GEF domain (GEFD2) acts on RhoA. Moreover, the co-expression of
both domains induces simultaneously the activation of both GTPases. To our
knowledge, this is the first example of a member of the Rho-GEF family, that
contains two functional exchange factor domains, with restricted and different
specificity. We are currently investigating how these GEF domains are activated,
by addressing the role of the PH domains in GTPases activation by Trio. We have
shown that: 1) the PH1 of Trio is necessary for Rac activation by the GEFD1; 2)
the PH1 of Trio targets the molecule to the cytoskeleton; 3) the GEFD1 domain of
Trio binds, in a two-hybrid screen, the actin binding protein filamin. These data
suggest that the PH1 targets Trio to the cytoskeleton close to Rac and its
effectors, probably via interaction with the actin-binding protein filamin,
consistent with a role of Trio in actin cytoskeleton remodeling.
PMID- 9759379
TI - [Raymond Latarjet, a scientist of the century].
PMID- 9759380
TI - [Algal toxins, inhibitors of serine/threonine phosphatases].
AB - Under certain environmental conditions, marine and freshwater phytoplankton may
produce phycotoxins inhibitors of serine/threonine protein phosphatases 1, 2A and
3. In the marine environment, dinoflagellates produce fatty polyethers: okadaic
acid and its derivatives, the dinophysistoxins, which accumulate in shellfish and
can cause diarrhetic shellfish poisoning (DSP) when ingested. In freshwater, the
toxins are microcystins and nodularin, 7 or 5 amino acid cyclic peptides and are
hepatotoxic. These toxins have caused massive poisoning of wild animals or
domestic livestock and now are a health threat for humans through use of drinking
and recreation water. Moreover, all these toxins are potent tumor promoters but
belong to a new class, different from the TPA class, because they do not act on
Protein Kinase C. Although the mutagenicity Ames test responds negatively,
several results show their genotoxic potential, and therefore they are a health
hazard through chronic exposition to low doses. Finally, okadaic acid, through
its easy penetration in all cellular types can be used as a tool to study
mechanisms involved in protein phosphorylation/dephosphorylation processes.
PMID- 9759381
TI - [Mechanism of action of neurotoxins acting on the inactivation of voltage-gated
sodium channels].
AB - This review focuses on the mechanism(s) of action of neurotoxins acting on the
inactivation of voltage-gated Na channels. Na channels are transmembrane proteins
which are fundamental for cellular communication. These proteins form pores in
the plasma membrane allowing passive ionic movements to occur. Their opening and
closing are controlled by gating systems which depend on both membrane potential
and time. Na channels have three functional properties, mainly studied using
electrophysiological and biochemical techniques, to ensure their role in the
generation and propagation of action potentials: 1) a highly selectivity for Na
ions, 2) a rapid opening ("activation"), responsible for the depolarizing phase
of the action potential, and 3) a late closing ("inactivation") involved in the
repolarizing phase of the action potential. As an essential protein for membrane
excitability, the Na channel is the specific target of a number of vegetal and
animal toxins which, by binding to the channel, alter its activity by affecting
one or more of its properties. At least six toxin receptor sites have been
identified on the neuronal Na channel on the basis of binding studies. However,
only toxins interacting with four of these sites (sites 2, 3, 5 et 6) produce
alterations of channel inactivation. The maximal percentage of Na channels
modified by the binding of neurotoxins to sites 2 (batrachotoxin and some
alkaloids), 3 (alpha-scorpion and sea anemone toxins), 5 (brevetoxins and
ciguatoxins) et 6 (delta-conotoxins) is different according to the site
considered. However, in all cases, these channels do not inactivate. Moreover, Na
channels modified by toxins which bind to sites 2, 5 and 6 activate at membrane
potentials more negative than do unmodified channels. The physiological
consequences of Na channel modifications, induced by the binding of neurotoxins
to sites 2, 3, 5 and 6, are (i) an inhibition of cellular excitability due to an
important membrane depolarization (site 2), (ii) a decrease of cellular
excitability due to an important increase in the action potential duration (site
3) and (iii) an increase in cellular excitability which results in spontaneous
and repetitive firing of action potentials (sites 5 and 6). The biochemical and
electrophysiological studies performed with these toxins, as well as the
determination of their molecular structure, have given basic information on the
function and structure of the Na channel protein. Therefore, various models
representing the different states of Na channels have been proposed to account
for the neurotoxin-induced modifications of Na inactivation. Moreover, the
localization of receptor binding sites 2, 3, 5 et 6 for these toxins on the
neuronal Na channel has been deduced and the molecular identification of the
recognition site(s) for some of them has been established on the alpha sub-unit
forming the Na channel protein.
PMID- 9759382
TI - [Anthrax toxins].
AB - Bacillus anthracis, a Gram positive bacterium, is the causative agent of anthrax.
This organism is capsulogen and toxinogenic. It secretes two toxins which are
composed of three proteins: the protective antigen (PA), the lethal factor (LF)
and the edema factor (EF). The lethal toxin (PA + LF) provokes a subite death in
animals, the edema toxin (PA + EF) induces edema. The edema and the lethal
factors are internalised into the target cells via the protective antigen. EF and
LF exert an adenylate cyclase and a metalloprotease activity respectively. The
structure-function relationship of these three proteins were defined using in
vitro and in vivo approaches.
PMID- 9759383
TI - [Scorpion toxins and defensins].
AB - The scorpion venoms possess many neurotoxic peptides which constitute a group of
molecular families with a common architecture and a high degree of polymorphism.
This architecture is found also in circulating antimicrobial peptides belonging
to the defensins family, which are especially structurally related to the
blocking potassium channels neurotoxins. The diversification in functions with a
unique architectural scheme is discussed taking in account the biophysiological
characteristics of the scorpion order.
PMID- 9759384
TI - [Anti-insect scorpion toxins: historical account, activities and prospects].
AB - Some toxins from scorpion venoms, much more toxic to insects than to other animal
classes, possess high affinity to Na+ channels. These anti-insect scorpion toxins
have been divided into: 1) alpha toxins which lack strict selectivity for
insects, do not compete with following groups of anti-insect toxins, resemble
other alpha scorpion toxins by their structure and their ability, as alpha
anemone toxins, to prolong insect axonal action potential durations through a
drastic slowing down of the Na+ current inactivation, 2) excitatory insect
selective scorpion toxins which induce in blowfly larvae an immediate fast
paralysis; in isolated cockroach axons, they depolarize and induce a sustained
repetitive activity of short (normal) action potentials through a shift of Na+
activation mechanism towards more negative potentials and some decrease of
inactivation at these potential values, 3) depressant insect selective
neurotoxins which cause a slow progressive flaccid paralysis of larvae,
depolarize insect axons and reduce or even suppress evoked action potentials;
resting depolarizations which are antagonized by a post-application of TTX, are
due to the opening of sodium channels at very negative potential values and to
the suppression of their inactivation mechanism. The decrease of the maximal Na+
conductance following flaccid toxin action may be understood if toxin-modified
channels opened at very negative potentials values remain open (or re-open) for
much longer times than in control conditions and pass by substate less conductant
states. Anti-insect scorpion toxins become of major interest into insect
neurophysiology and also into insect pest control, due to their specific target
sites and to the recent constructions of insecticidal baculovirus expressions of
several of these toxins.
PMID- 9759385
TI - [Implications of bacterial protein toxins in infectious and food-borne diseases].
AB - Among the 315 protein toxins elicited by gram positive and gram negative bacteria
so far characterized, about 50 toxins are currently considered as totally or
partially, responsible of the pathological manifestations and/or lethality
resulting from host infection or intoxication (contaminated food) by relevant
toxinogenic bacteria. A certain number of criteria are required for the
assessment of indisputable involvement of a toxin or an array of toxins (from the
same bacteria) in infectious diseases: 1) The bacterial microorganism clearly
identified as the pathogenic agent of the disease produces component(s)
considered as toxin(s); 2) The administration to appropriate animal(s) of the
toxin(s) separated from the relevant bacteria or produced by genetic engineering
from a heterologous tox+ recombinant bacterial strain produces symptoms and
pathophysiological disorders that mimic those observed in the natural disease or
at least those elicited in experimental animals by the cognate toxin-producing
bacteria; 3) The in vitro incubation of the isolated toxin(s) with appropriate
animal organs, tissues or cells elicits certain pathophysiological, biochemical
or metabolic manifestions observed in the host infected with the relevant
toxinogenic bacteria; 4) Toxin concentration in the organism of the host infected
by the toxinogenic bacteria should be compatible with the characteristics of the
relevant disease. The toxins of pathogenic interest exhibit a variety of effects
in bacterial diseases. Bacteria that colonize a wound or mucosal surface but do
not invade target cells can produce toxins that act locally or enter the
bloodstream and attack internal organs (e.g. Corynebacterium diphtheriae, Vibrio
cholerae, ...). Bacteria growing in a wound can produce toxins that destroy host
tissue and kill phagocytes in the immediate vicinity of the bacteria, thus
facilitating bacterial growth and spread. On the basis of the above mentioned
criteria, the following bacterial diseases among many others are toxin-associated
(toxinoses): diphtheria, tetanus, botulism, whooping cough, diarrhea, bloody
diarrhea, hemolytic uremic syndrome, cholera, scarlet fever, toxic shock
syndrome, gas gangrene, B. fragilis diarrhea, anthrax, pseudomembranous colitis.
PMID- 9759387
TI - [The role of peptidic toxins in the pharmacological approach of the diversity of
calcium channels].
AB - Peptidic toxins extracted from spider, marine snails or snakes venoms, have
considerably helped the pharmacological characterization of calcium channels.
They have successfully been used for calcium channels mapping. However, the
actual situation remains unclear. Genetic investigations demonstrated the
existence of a great number of types or sub-types of calcium channels. In recent
year a large number of toxins have been purified. Many of these toxins have
specific actions on calcium channels and have been used as powerful tools in
pharmacological approaches of calcium channels. However the pharmacology of the
calcium channels remains very limited, many of them are waiting for the discovery
of pharmacological tools allowing their molecular approach in order to
determinate their biological implications. In this paper we describe the
different families of calcium channels and toxins that interact with these
channels. We also recapitulate the "non defined" calcium channels i.e. calcium
channel which does not correspond to a N, L, P/Q, R or T type channel and for
which no effector are available. We report the discovery and characterization of
mapacalcine, a toxin extracted for a marine sponge, as an example of an approach
of an undefined calcium channels first characterized by electrophysiological
techniques and for which a specific toxin has been purified allowing its
pharmacological approach. We also state the possible role of calcium channel
toxins in the domain of therapeutic applications.
PMID- 9759386
TI - [Pharmacological properties of fish venoms].
AB - Fish venoms can be lethal for Vertebrates. The effect depends of dose and
subject, more than incriminated fish. The most constant symptom is a violent
pain; but the serious pharmacological effects are respiratory and heart failure
with marked hypotension and cardiac perturbations, neurologic damage, such as
seizure and coma. Experimentation is difficult due to venom instability. Activity
is lost by distilled water, lyophilisation in buffers, several successive
freezing and defreezing. In addition, when venom is broken, other pharmacological
effects are evidenced, for instance, with Synanceia verrucosa venom, hypertensive
phase takes the place of hypotension. It is difficult to distinguish toxin effect
from this of denaturation products of the toxin. Noradrenaline is present in
Synanceia venom, and it seems that acetylcholine exists in some venom, at least
when diluted in saline solution. Other biological active products are present.
Purified toxins allow pharmacological investigations. Stonefish venom is better
studied, because venomous glands contain relatively high venom quantity.
Stonustoxin from Synanceia horrida exerts its action through NO-synthase
liberation, and its primary action can be attributed to its potent vasorelaxant
activity, causing a rapid, marked and irreversible hypotension. Trachynilysin,
from Synanceia trachynis, causes massive release and depletion of acetylcholine
and damage to nerve and muscle fibres, which can account for the inhibition of
neuromuscular function, and skeletal paralysis. But the used doses are not
compatible with respiratory arrest. Verrucotoxin from Synanceia verrucosa
activates potassium channels dependent from ATP; this can explain damage, and
probably neurologic and respiratory distress.
PMID- 9759388
TI - [A new photocoagulation technic for severe non-proliferative diabetic
retinopathy. A prospective study apropos of 54 cases].
AB - PURPOSE: This work deals with the photocoagulation treatment of severe NPDR,
suggesting a new therapeutic practice. It is proposed to adopt treatment
intensity to each clinical form, to preserve healthy territories through
biomicroscopy and to evaluate the risk of complications inherent in this
technique, and to be at least as efficient as comparative studies. MATERIAL AND
METHOD: We treated 52 eyes and kept under observation 2 eyes which revealed
severe NPDR. The patients were followed between 1991 and 1996. The approach was
essentially biomicroscopic. Photocoagulation treatment utilized green, yellow or
orange wavelengths through panoramic contact lenses. RESULTS: After an average
follow-up of 30 months, there was a decrease of visual acuity of 0.72 to 0.64
(Monoyer scale); a severe visual loss in 1.8% of the cases; and an early decrease
in visual acuity at 6 weeks in 7.4% of the cases. A "High Risk" PDR occurred in
3.7% of the cases and we had to perform a vitrectomy (1.85% of the cases). We
treated with less than 1600 I in 68.5% of the cases and with more than 1600 I in
31.5% of the cases. Patients had 5.5 photocoagulation sessions and were examined
every 3.5 months on average. CONCLUSION: We believe our therapeutic approach is
interesting, by comparison with other studies, but that it can be improved. All
patients show a primary condition in the nasal field which, if treated too
massively, becomes unable to see and disturbs daily life. We also note the severe
potential for progression in insulin-dependent patients.
PMID- 9759389
TI - [A comparative study of thio-tepa and mitomycin C in the treatment of pterygium.
Preliminary results].
AB - AIMS: To compare the efficacy of Thio-tepa and Mitomycine C to obviate
recurrence; to compare cost-efficacy ratios; to evaluate their facility of use
and their complications. METHODS: In a prospective blinded study, 36 patients
undergoing surgery for 46 primary and recurrent pterygium were assigned randomly
to three groups: group 1 received 0.02 mg/ml of Mitomycine C three times daily
for 5 days; group 2 received Thio-tepa four times daily for 6 weeks, group 3
served as a control receiving distilled water three times daily for five days.
RESULTS: Recurrence rates were 38%, in group 1; 28% in group 2; 82% in group 3
respectively. Follow-up ranged from 15 to 44 weeks (mean 27.93 +/- 8.9 weeks).
Mean delay recurrence time was 6.3 weeks. Topical Mitomycin caused: iritis,
conjunctival irritation, excessive lacrymation, photophobia, ocular pain; Thio
tepa caused: photophobia, foreign body sensation, headache. CONCLUSIONS:
Mitomycine C appears to be an effective and safe adjunctive treatment for this
cost-efficacy and this facility of use comparison.
PMID- 9759390
TI - [Culture of human keratocytes. Influence of culture conditions and
ultrastructural aspects].
AB - BACKGROUND: To investigate the influence of fetal calf serum (FCS) and fibroblast
growth factor (FGF) on human keratocyte growth in vitro and cell differentiation,
and to describe cultured human keratocyte ultra-structure. METHODS: Human
keratocytes were cultured in TC 199/Ham F12 media, supplemented or not with 10%
FCS, aFGF, and bFGF. Keratocyte growth was studied. Cultured keratocytes were
analyzed by means of immunochemistry and transmission electron microscopy.
RESULTS: Without fetal calf serum, cell population doubling occurred after 7 days
of culture and no alpha smooth muscle-actin cell expression was observed. With
serum, cell population increased by 1 log after 7 days of culture and all of the
cells were alpha SM-actin + bFGF or aFGF-addition to the serum-containing medium
resulted in a dramatic decrease in this alpha SM-actin expression. Nuclei were
found to be oval and regular in cross-sections, and round and indented in frontal
sections. Numerous cytoplasmic organelles were observed, as were cell expansions,
gap junctions, omega-shaped structures, and fenestrations. Cultured keratocytes
synthesized collagen fibers and filaments. CONCLUSION: Fetal calf serum allows
human keratocytes to grow with a myofibroblast cell phenotype, whereas addition
of FGF results in a fibroblast cell phenotype. Ultrastructure of cultured
keratocyte is similar to that observed in situ.
PMID- 9759391
TI - [Therapeutic and prognostic problems of traumatic cataracts. Apropos of 45
cases].
AB - PURPOSE: The purpose of this study was to investigate clinical profile, prognosis
and therapeutics problems of traumatic cataract. MATERIAL AND METHODS: A
retrospective study was conducted in 45 cases of traumatic cataracts (1993-1996).
Mean age was 19 years, principally male. We chose the extracapsular extraction
with implantation in 28 cases. RESULTS: Overall results were satisfactory (62%
with VA > 2/10); they are better in patients with implantation and poorer in
infants. Postoperatively, most complications were major inflammatory and
secondary capsular opacification essentially children. The importance of systemic
corticotherapy and prevention of amblyopia in children is emphasized.
PMID- 9759392
TI - [Visual prognosis factors in congenital cataract].
AB - PURPOSE: Study of different factors which can change the visual prognosis in
congenital cataract. METHODS: One hundred seventy eyes of 100 children with
congenital cataract are operated by extracapsular cataract extraction with limbic
incision. Posterior rhexis and anterior vitrectomy were associated in children
under 2 years. Implantation was used in 42%, contact lens in 8%. Other cases were
corrected by glasses. The prognostic factors studied were: uni- or bilaterality,
partial or complete aspect of cataract, age of apparition and management, and
association with other malformations. RESULTS: Only 9 eyes out of 30 with
unilateral congenital cataracts had visual acuity > or = 2/10; 44.4% of bilateral
cataracts had visual acuity > or = 2/10; The best visual acuity was noted in
progressive and partial cataract without associated malformations.
PMID- 9759393
TI - [Bilateral ischemic optic neuropathy secondary to acute ergotism].
AB - We report a case of a 31 year-old man who presented a bilateral ischemic optic
neuropathy associated with headaches and severe systemic hypertension. This
episode appeared after administration of ergotamine tartrate and macrolides. This
medication probably led to a vasospasm which occurs in patients with
hypertension. The cardiovascular and serum lipid evaluations were normal. A
migraine optic neuropathy can be evoked.
PMID- 9759394
TI - [Episcleritis and brucellosis. Apropos of a case].
AB - A 35-year-old man presented a case of recurrent episcleritis revealing
brucellosis. No concurrent diagnosis other than brucellosis could account for the
episcleritis. Moreover his status was dramatically improved by specific
antibiotherapy. A review of the literature showed that uveitis and optic
neuropathies are the most common ocular manifestations of brucellosis. To the
best of our knowledge, this is the first case of episcleritis associated with
brucellosis.
PMID- 9759395
TI - [Choroid melanoma associated with 2 other primary malignant lesions. Apropos of a
case].
AB - A case of choroidal melanoma associated to two other primitive malignancies is
reported. The patient, a 65-year-old woman had an amelanotic choroidal tumor of
her left eye. In her clinical history was found a previously treated kidney
carcinoma eight years ago. A choroidal metastasis was therefore diagnosed. After
radiation therapy, an initial regression was observed. Fifteen months later, the
tumor grew again. Enucleation was performed, and histopathology concluded on
choroidal malignant melanoma. Three years later, a mammal carcinoma was
discovered and treated by mammectomy. Her ophthalmologic and general status
remained normal until now. Amelanotic choroidal tumors are difficult to diagnose.
Regular follow-up can lead to a change in the diagnosis. The occurrence of
multiple cancers is still not fully understood.
PMID- 9759397
TI - [Acute open-angle glaucoma in a woman with AS hemoglobinopathy].
AB - A 64-year-old black woman presented unilateral acute ocular hypertension.
Gonioscopy showed a blood clot obstructing Schlemm's canal. Intraocular pressure
returned to normal values after resorption of the blood clot. Hemoglobin
electrophoresis found a sickle-cell trait, raising the hypothesis that the
obstruction of outflow was probably due to the mechanism of sickling.
PMID- 9759396
TI - [Papillary edema and the POEMS syndrome].
AB - POEMS syndrome is a multisystem disorder associated with plasma cell dyscrasia.
Papilloedema is a feature of this syndrome with an incidence ranging from 33% to
84% in published reports. Its pathogenesis remains unclear. We present an
observation that clearly demonstrates the difficulties to diagnose this
affection. POEMS syndrome can be accepted as one of the various etiologies of
papilloedema. Considering this observation and the recent publications, different
pathological hypothesis are reviewed.
PMID- 9759399
TI - [Isolated and primary palpebro-conjunctival amylosis. Apropos of 2 cases].
AB - Ocular amyloidosis a an uncommon condition and conjunctival involvement rarely
occurs, representing 15% of all ocular localizations. Clinical manifestations
show a polymorphism requiring a histological diagnosis. Based on two cases of
primary isolated conjunctivo-palpebral amyloidosis, we discuss the different
ocular sites. The first case involved false ptosis, a conjunctival infiltration
and a lower eyelid tumefaction; all located in the left eye. The second case had
ptosis, a right lower eyelid tumefaction with ectropion and esthetic damage.
Amyloidosis was confirmed at histologic examination of the conjunctival mucous
after a special congo red coloration. In order to affirm the isolated
conjunctival localization, it is necessary to eliminate another amyloidis site.
The treatment was surgical with excision and cure of ptosis. Ocular amyloidosis
is a rare condition with polymorphism manifestations. Confirmation is
histological. The greatest difficulty is management due to disease recurrence.
PMID- 9759398
TI - [Surgical treatment of retrofoveal choroid neovascularization in multifocal
choroiditis].
AB - BACKGROUND: Surgical removal of subfoveal choroidal neovascularization allows
visual improvement, especially in young patients. METHODS: Three eyes of 3
patients were prospectively studied. Subfoveal choroidal neovascularization was
related to presumed ocular histoplasmosis syndrome. The surgical procedure
included vitrectomy, surgical excision of the neovascular membrane, and air
tamponnade. RESULTS: Follow-up was 6, 12 and 20 months. Vision improved in 2
eyes. In one case, recurrent extrafoveal neovascularization was treated with
laser photocoagulation. DISCUSSION: Surgery seems to be an alternative to
photocoagulation in subfoveal choroidal neovascularization in presumed ocular
histoplasmosis.
PMID- 9759400
TI - [Biocompatibility of a porous alumina orbital implant. Preliminary results of an
animal experiment].
AB - PURPOSE: Evaluation of clinical tolerance and scanning electron microscopy study
of the bio-colonisation of a porous ceramical alumina implant after evisceration
of the rabbit. Preliminary results. METHODS: Sixteen white New Zealand rabbits
were eviscerated. A porous hydroxyde alumina ball was implanted in the opened
sclera and explanted 15, 30, and 90 days after implantation. Clinical tolerance
was assessed and implant tissular ingrowth was analyzed by scanning electron
microscopy. RESULTS: One infection was observed and there was no conjunctival
breakdown. Fibrovascular ingrowth occurred as soon as 15 days after implantation,
and was full at one month. CONCLUSION: Porous alumina implant orbital tissue
tolerance and fast fibrovascular ingrowth in the rabbit socket suggest promising
result in the human anophthalmic socket.
PMID- 9759401
TI - [Surgery of intravitreous nuclear luxations post-phacoemulsification].
AB - PURPOSE: To evaluate anatomical and functional results after surgery of retained
nucleus or nuclear lens fragments into the vitreous cavity after
phacoemulsification. METHODS: Files of 46 patients that underwent vitrectomy for
posterior retained nuclear fragments between July 92 and June 96 were studied
retrospectively. Minimum follow-up was 6 months. Patients having only cortical
material were excluded. In 34 cases the nucleus or nuclear fragments were removed
posteriorly during a pars plana vitrectomy using either fragmentation with
fragmatome (13 cases) or cutting with the vitreotome tip (21 cases). Anterior
removal after pars plana vitrectomy was performed in 12 cases. 20 patients were
operated on the first week, 12 during the second week and 14 after the second
week following phacoemulsification. RESULTS: Forty-one per cent of the patients
reached 20/40 or better. 28% had less than 20/200. 8 (17%) patients presented a
retinal detachment, 6 a cystoid macular edema, 6 a bullous dystrophy, and 9 an
elevated intraocular pressure. At the end of follow-up 89% have been implanted
(50% had been implanted at the end of the cataract surgery). We found no
correlation between visual acuity and timing of surgery, anterior or posterior
site removal of nuclear fragments or lens implantation during
phacoemulsification. CONCLUSION: Dislocation of the nucleus into the vitreous
cavity is a serious event during phacoemulsification because of its inflammatory
and retinal complications. Vitreoretinal surgery allows good visual recovery in
about half of the patients. Technical handling depends primarily on the nucleus
density. An IOL may be placed at the end of phacoemulsification if the nucleus is
not too hard and if the anterior segment has been cleaned carefully.
PMID- 9759402
TI - [Juvenile glaucoma. Seven case reports].
AB - BACKGROUND: Juvenile glaucoma is an uncommon form of chronic open angle glaucoma
that appears between 3 and 35 years of age. METHODS: We report in this study
seven cases of juvenile glaucoma that occurred in patients melanoderma. RESULTS:
Three of them had unilateral blindness and in two others visual acuity was
reduced to light perception in one eye. The intraocular pressure is above to 30
mmHg in 64.3% of the cases and a myopia was frequently associated. CONCLUSION:
The insidious development of this pathology and the difficulty of its diagnosis
among children often result in severe clinical manifestations with high visual
field defects and optic disc cuppings particularly in melanoderma patients.
Recent studies have proved autosomal dominant transmission with variable
penetrance for one kind of juvenile glaucoma and location of the defective gene
on chromosome 1q.
PMID- 9759403
TI - [Rapid Tendency Oriented Perimeter (TOP) with the Octopus visual field analyzer].
AB - PURPOSE: To study the capabilities of a new perimetric strategy with the Octopus
visual field analyzer: the Tendency Oriented Perimetry. METHODS: Tendency
oriented perimetry (TOP) attempts to assess the visual field by using answers to
questions to establish thresholds in the neighboring area. We evaluated 79 visual
fields with the Octopus strategy using the program 32 and the TOP strategy split
into the following groups: normal visual field or glaucoma suspects (52),
moderately advanced glaucoma (16), advanced glaucoma (11). The following
parameters were analyzed for the two strategies studied: examination time, MS
(means sensitivity), MD (mean defect), LV (Loss Variance), short term fluctuation
(RF) and the number of points with a deficit with different p values: p < 0.5; p
< 1; p < 2; p < 5. RESULTS: TOP perimetry showed a significant reduction of
exploration time: 11.87 minutes with the Octopus 32 vs 2.49 minutes with the TOP
strategy (p < 0.001). There is no significant modification for the other
parameters (MD, MS, RF) except for the LV (Loss Variance) for the global analysis
and for each separate group. CONCLUSION: The TOP strategy reduces examination
time significantly but seems to be less accurate especially for the calculation
of the depth of each scotoma in comparison with the standard Octopus 32
perimetry.
PMID- 9759404
TI - [Indocyanine green angiography of basal laminar drusen in the retinal pigment
epithelium associated with vitelliform macular degeneration].
AB - PURPOSE: In the mid-late life, basal laminar drusen can be associated with
vitelliform macular degeneration and choroidal neovascularization. The
differential diagnosis between these two clinical entities is not always easy
with fluorescein angiography. The aim of this case report is to describe the
indocyanine green angiographic features of basal laminar drusen and pseudo
vitelliform material and to evaluate the role of ICG angiography in
differentiating new choroidal vessels from vitelliform macular degeneration.
PATIENTS AND METHODS: Six patients (12 eyes) with central visual loss and
metamorphopsia underwent a biomicroscopic examination. Diagnosis was basal
laminar drusen and bilateral vitelliform macular degeneration. Fluorescein and
indocyanine green angiographies were performed and the results were compared.
RESULTS: In all eyes, basal laminar drusen were hyperfluorescent with both
angiographies. On fluorescein angiography, the macular material was
hypofluorescent early, but gradual staining occurred from the borders in the late
phase. In 8 out of the 12 eyes, fluorescein angiographic characteristics of the
macular lesions could not provide clues to differential diagnostic between new
choroidal vessels and vitelliform material. On indocyanine green angiography, in
8 eyes the material remained intensely hypofluorescent during the whole sequence.
In 4 eyes, indocyanine green angiography allowed the identification of
hyperfluorescent well-defined new choroidal vessels. CONCLUSIONS: Indocyanine
green angiography allows the visualization of basal laminar drusen and can easily
differentiate choroidal neovascularization from acquired vitelliform
degeneration.
PMID- 9759405
TI - [Intra-corneal rings for the correction of weak myopias].
AB - OBJECTIVES OF THE STUDY: Intra-stromal rings (ICR) represent a new method for low
myopic correction. An indirect central flattening is induced by a peripheral
steepening related to the segments. This surgery was recently approved in Europe,
but is still under evaluation in the multicenter study controlled by the FDA
(Food and Drug Administration). We took part in that protocol and report our
results at one year follow-up. MATERIAL AND METHOD: Twenty-five patients were
included in the study with 47 operated eyes and a follow-up between 3 to 18
months. Data relative to refractive results, quality of the vision and anatomic
changes induced by intrastromal segments will be collected at the issue of a
rigorous survey. RESULTS: At one year, non-corrected visual acuity was 20/40 or
better in 100% and 20/20 in 60%. We noted no loss in best visual acuity and an
improvement of one or two lines in 20% of operated eyes. No significative changes
were observed concerning: intraocular pressure, corneal sensitivity, central
pachymetry or corneal endothelium. Three eyes had to be explanted and recovered
the preoperative refraction. No severe complications were observed. DISCUSSION:
Analysis of results is in favor of the efficacy, predictability and
reproductibility of the surgery, which might be better with rings of a diameter
under 0.40 mm. Occurrence of postoperative astigmatism appears to constitute the
main limit suggesting discussion on etiologic factors and modalities of
treatment. CONCLUSION: This concept of intra-corneal rings appears particularly
promising for correction of low myopia and maybe in the near future for
correction of others ametropia, requiring design of new specific segments.
Essential interest of this surgery is the respect of the central area and its
potential reversibility.
PMID- 9759406
TI - [Value of lacrymal IgE determination and conjunctival cytology in the diagnosis
of chronic conjunctivitis].
AB - PURPOSE: Chronic conjunctival inflammatory diseases may depend upon various
strongly intricated mechanisms. Discriminating allergy from nonspecific
inflammation has become of striking importance for diagnosis and treatment. We
investigated conjunctival inflammatory response by comparing two objective
biological tools, tear IgE detection and HLA DR expression by conjunctival
epithelium, as indirect indicators of activation of the Th1 and Th2 subsets,
respectively. METHODS: Sixty-eight patients (135 eyes) with chronic
conjunctivitis underwent tear IgE dosage by an ELISA technique and quantification
of HLA DR expression in impression cytology specimens. 34 had direct or indirect
clinical indications of allergic mechanisms, 22 had chronic conjunctivitis
without any sign of allergy, and 12 suffered from isolated nonallergic dry eyes.
RESULTS: Patients clinically considered as allergic only showed positive IgE in
31 out pf 68 eyes (46 per cent), whereas 11/44 (25%) and 7/24 (29%) eyes with
nonspecific conjunctivitis and dry eyes respectively were also positive. HLA DR
positivity in epithelial cells was found in 18/61 (29.5%), 15/40 (37.5%) and 9/22
(41%) eyes, respectively. HLA DR expression by epithelial cells was negatively
correlated with tear IgE, as most specimens positive to one criterion were
negative to the other one (37 eyes DR+ IgE-, 35 eyes DR- IgE+, and 5 eyes DR+
IgE+; chi-square: p = 0.0001). CONCLUSION: As IgE synthesis and HLA DR induction
may represent indirect indicators of the activation of the Th1 and Th2 subsets,
association of these two simple tests could be interesting for the routine
assessment of the mechanisms of inflammatory ocular surface diseases.
PMID- 9759407
TI - [Choroidal metastases of a bronchial carcinoid tumor. Review of cases in the
literature. A case report].
AB - Carcinoid tumors are rare tumors with low malignancy. They are most often located
in the digestive system and the bronchial tree. They metastasize to the lymph
nodes, liver, bones and very rarely to the eye. Choroidal metastases almost
always originate from the bronchial tree. Inversely, most orbital metastases
originate in the digestive tract. Sometimes they have an orange color useful for
diagnosis. We report the case of a woman who developed a bronchogenic carcinoid
tumor at the age of 18, and presented five years later with bilateral and
multifocal choroidal metastases. There was no other metastatic site. She has been
treated with photocoagulation and cryotherapy. From the 25 previously reported
cases, one can summarize that these specific metastasis grow slowly and allow
good long-term survival.
PMID- 9759408
TI - [Ocular trauma and caustic burns by air bags].
AB - We report two cases of ocular injuries caused by airbag inflation. These cases
illustrate two main types of airbag-induced eye injuries: chemical and traumatic.
In the first case, chemical keratitis was caused by the aerosol spray of alkaline
particles produced by the airbag deployment system. In the second case, the high
speed deployment system caused mechanical injury to the anterior and posterior
segments demonstrating the effect of the sudden deceleration when the individual
hits the airbag. These two cases as well as others reported in the literature
suggest that ocular injury should always be suspected because of the inherent
traumatic effect of the airbag protection system.
PMID- 9759409
TI - [Unilateral retinoblastomas with late bilateralization. Three case reports].
AB - Three cases of unilateral retinoblastoma with late bilateralization are presented
in this study. The rare occurrence of this event underlines the need for
prolonged follow-up in the fellow-eye, even in the absence of familial
retinoblastoma. In these three cases, the first affected eye was enucleated after
a diagnosis made at three months, sixteen months and three years of age. New
tumors appeared in the second eye when the children were sixteen years old in one
case and five years old in two cases.
PMID- 9759410
TI - [Capsular bag distension syndrome after capsulorhexis].
AB - We present one case of capsular bag distension associated with lens
phacoemulsification, capsulorhexis and posterior chamber intraocular lens (IOL)
insertion. Capsular bag distension is a rare postoperative complication of
continuous tear anterior capsulotomy and presents the following characteristics:
(1) postoperative myopic over-refraction; (2) shallowing of the anterior chamber
associated with anterior shift of the IOL and the iris diaphragm; (3) important
posterior distension of the posterior capsule and (4) sealing of the capsule to
the anterior surface of the IOL. In our case, recovery of vision was incomplete
after cataract surgery although the procedure was uneventful and no other ocular
pathology was found. A neodymium: YAG laser anterior capsulotomy peripheral to
the edge of the IOL remedied the situation allowing the capsular fluid to regress
into the anterior chamber and the IOL to return in a normal posterior position.
PMID- 9759411
TI - [Laser CO2 and ocular plastic surgery].
PMID- 9759412
TI - [Retinal vein occlusion and lipoprotein (a)].
AB - PURPOSE: Epidemiological studies have shown a significant correlation between
increased levels of lipoprotein (a) and coronary and cerebral vascular diseases.
Lipoprotein (a) presents a striking homology with plasminogen and may therefore
complete with binding of plasminogen at fibrin and at the endothelial cell
surface, leading to fibrinolytic system dysfunction. The aim of this work is to
study the relationship between increased levels of Lp(a) and retinal vein
occlusion. METHODS: 132 consecutive patients with retinal vein occlusion were
screened for lipoprotein (a) level. They also underwent initial and final visual
acuity measurement, fluorescein angiography and blood tests including glucose,
cholesterol and triglyceride levels, apolipoprotein A1 and B, protein
electrophoresis, coagulation tests. Lipoprotein (a) results were compared with
those of 52 age, sex and cardiovascular risk factors-matched controls. RESULTS:
Lipoprotein (a) values were significantly higher in the retinal vein occlusion
group than in the control group (p = 0.05). Elevated lipoprotein (a) (> 0.1 g/l)
levels were observed more often in retinal vein occlusion patients (61%) than in
the controls (42%; p < 0.02). No correlation was found in retinal vein occlusion
patients between high levels of lipoprotein (a) and a severe form of retinal vein
occlusion. Lipoprotein (a) levels were similar in central vein and branch vein
occlusion patients. CONCLUSION: Lipoprotein (a) has been shown to be correlated
with cardiovascular disorders and may also be involved in retinal vein occlusion,
probably by dysfunction of the fibrinolytic system. However, it does not seem to
be a prognostic factor of retinal vein occlusion and its role has to be
elucidated in further studies.
PMID- 9759413
TI - [Clinical features and genetic analysis in a family with X-linked incomplete
congenital stationary night blindness (CSNBi)].
AB - PURPOSE: We describe particular clinical features in a three-generation family
with X-linked CSNBi and present the genetic analysis. METHOD: The diagnosis of
CSNBi was established on clinical and electrophysiological criteria. Polymorphic
DNA markers of the Xp region were analyzed by fluorescent polymerase chain
reaction. RESULTS: Clinical findings evidenced an atypical association of both
myopia and hyperopia in the same brotherhood. The most interesting feature in
this family was the observation of major worsening of the clinical shape between
the first and the third generation of affected individuals. DNA analysis did not
show significant linkage between the disease and markers of the Xp11-p21 region.
Southern analysis did not show expansion of trinucleotide repeat CAG/CTG and
CCG/CGG over the three generation. CONCLUSION: Haplotypic analysis together with
clinical observations allow to exclude the existence of a myopia gene closely
linked to the CSNB2 locus. The clinical anticipation observed in this family does
not seem to be linked with trinucleotide repeat expansion CAG/CTG or CCG/CGG.
PMID- 9759414
TI - [Intracameral lidocaine and phacoemulsification under topical anesthesia. Apropos
of 80 operations].
AB - PURPOSE: To evaluate the advantage of intracameral unpreserved lidocaine for
patient comfort during phacoemulsification under topical anesthesia. METHODS: In
this prospective study, we performed 80 phacoemulsifications under topical
anesthesia, with tetracaine 1% drops, 10 minutes before and at the start of
surgery: 40 patients received 0.3 cc balanced salt solution (BSS) intracameral
injection; 40 patients received 0.3 cc unpreserved lidocaine 1% intracameral
injection. The same surgical procedure was performed in both groups: 3.2 mm
temporal corneal self-sealing incision, capsulorhexis, foldable polyHEMA IOL
implantation into the capsular bag. There was no intravenous sedation. RESULTS:
Forty-eight percent (19) in the BSS group and 70% (28) in the lidocaine group
felt no pain. 10% (4) in the BSS group reported sharp pain during
phacoemulsification. During IOL insertion, no pain was reported by 48% (19) in
the BSS group, and 75% (30) in the lidocaine group; 10% (4) in the BSS group felt
severe pain (significant difference: p < 0.05). Endothelial cell loss was 6% in
the BSS group, and 6.4% in the lidocaine group (non significant difference).
CONCLUSION: Intracameral lidocaine is safe and effective in decreasing discomfort
among patients undergoing phacoemulsification under topical anesthesia.
PMID- 9759415
TI - [Evaluation by laser flare meter of the inflammatory response after cataract
surgery].
AB - PURPOSE: To prospectively evaluate use of the laser flare meter the inflammatory
response after phacoemulsification with four different types of intraocular
lenses. METHODS: Measurements with the Kowa laser flare meter FC-500 were done
before surgery and at 1, 6 and 21 days following standard phacoemulsification
with corneal incision in 157 patients. The patients were randomized in four
groups to receive HSM IOL (group I), foldable acrylic IOL (group II), foldable
three-piece silicone (group III), and foldable single-piece silicone (group IV).
RESULTS: Overall, mean flare values were increased at D1, and decreased rapidly
to normal values at D21. Intragroup analysis showed a slight increase of flare
value observed in the PMMA group (p = 0.0015) and silicone monobloc group (p =
0.001) at D21 compared to D0. There was no statistical difference found between
D0 and D21 in the acrylic and the silicone three pieces groups. At D1, a
significant increase of flare values was observed in the PMMA (28.9 ph/ms) and
silicone three pieces (28.8 ph/ms) groups, as compared to silicone monobloc group
(22 ph/ms). At D21, the acrylic group had a significantly lower mean value than
PMMA and silicone monobloc groups. No statistical difference was observed between
acrylic and three-piece silicone at D21. CONCLUSION: This study shows that the
inflammation in the four groups was very low after phacoemulsification by a
corneal incision and attempts to explain the impact of the incision length on the
breakdown of blood-aqueous barrier.
PMID- 9759416
TI - [Scale for evaluating desirable ametropia or eumetropia].
AB - GOAL: The purpose of this study is to assess the degree of desirable ametropia in
cataract surgery. MATERIAL AND METHODS: A scale for evaluation was created. It
allows to measure the desired distance for a neat uncorrected vision (desired
ametropia) after cataract surgery that presbyopic patients (monocular vision)
would like to obtain. This scale helps to calculate the power of the intraocular
lens to be implanted. The scale was shown to a series of 50 consecutive
presbyopic patients. Refraction was the same in both eyes. The interest of
patients in the evaluation of their desirable ametropia was measured on a scale
from 0 to 5. RESULTS: Interest was good for 50% of patients (grade > or = 3).
Mean distance desired by patients for a neat uncorrected vision was 1 meter.
Preoperative myopia and hyperopia have no significantive influence upon the
distance desired for a neat uncorrected vision. CONCLUSION: The choice of the
power of the lens implanted during cataract surgery should take into account the
patients' desires. An evaluation of the postoperative desirable ametropia should
be systematic.
PMID- 9759417
TI - [Brown syndrome: current status].
AB - PURPOSE: Brown's syndrome is a form of anatomical strabismus, or retraction
syndrome. It is defined by active and passive limitation of upward gaze in
adduction in the field of action of the inferior oblique muscle. The etiology of
Brown's syndrome remains unknown. The defect lies at the level of the superior
oblique's tendonis trajectory via the trochlea. We studied the frequency of
clinical signs and results after surgery in patients presenting congenital
Brown's syndrome. PATIENTS AND METHODS: Our study involved 18 children. They all
underwent complete ophthalmological examination with orthoptic testing, pre and
postoperatively. RESULTS: Neither sidedness nor predominance of sex was noted.
Compensatory head posture was noted in 7 of 18 cases. Limitation of upward gaze
in adduction was a constant finding, with a positive duction test. Eleven cases
underwent superior oblique recession. Results of surgery were satisfactory, with
resolution of compensatory head posture in over 80% of cases. CONCLUSION: The
etiology of congenital Brown's syndrome remains unknown. The different surgical
techniques give inconstant results. Operative indication is decided only when in
the presence of well defined clinical manifestations: CHP, deviation in primary
position with alteration of binocular vision.
PMID- 9759418
TI - [Panophthalmitis and results of HIV tests. Experience at the Cocody University
Hospital Center in Abidjan, Ivory Coast].
AB - PURPOSE: We assessed the frequency of panophthalmitis in HIV-infected patients.
MATERIALS AND METHODS: Thirty-seven cases of panophthalmitis were screened out of
420 hospitalized patients of ophthalmology department of Cocody Teaching
University Hospital, Abidjan, Ivory Coast, from January to October 1995. HIV
tests were performed in 11 patients. RESULTS: Mean age was 40 years (from 10
months to 75 years). Four patients (36.4% of tested patients) were infected by
HIV. Contrary to seronegative patients, panophthalmitis cases in HIV-infected
patients occurred spontaneously without any apparent exogenous cause (foreign
bodies). Most of patients were young (from 18 to 47 years old). CONCLUSION: We
draw the attention of eye specialists of the frequency of panophthalmitis without
exogenous apparent cause in HIV patients. It would be interesting to perform a
transvitreal needle biopsy in order to search for intraocular toxoplasmosis that
should be the first cause.
PMID- 9759419
TI - [Ultrastructural and immunohistochemical study of 3-dimensional cultures of human
keratinocytes on a collagen gel].
AB - PURPOSE: To investigate the ultrastructural and immunochemical features of three
dimensional cultures of human keratocytes in collagen gel matrix. METHODS: Human
keratocytes were obtained from primary cultures of stromal explains. They were
cultured in bovine type I collagen gel matrix for 6 weeks. Keratocyte-populated
gels were analyzed by means of immunochemistry and transmission electron
microscopy. RESULTS: Human keratocytes cultured in collagen gel matrix developed
processes and formed networks of connecting cells. They showed positive staining
for vimentin, collagen I, V, and VI, and connexin. Electron microscopy showed
elongated cells with processes and gap junctions. Keratocytes synthesized
collagen fibrils and filaments. No fibrils' organization similar to that observed
in the normal human corneal stroma (i.e. parallel bundles of collagen fibrils)
was observed. CONCLUSION: Ultrastructure and immunochemical phenotype of three
dimensional cultures of human keratocytes in collagen gel matrix are similar to
those observed in situ. These cultures represent a useful in vitro model to study
the different corneal stroma components.
PMID- 9759420
TI - [Retinoblastoma: importance of genetic counseling].
PMID- 9759421
TI - [Nummular keratopathy in Crohn's disease. Apropos of a case].
AB - We report an unusual case of nummular keratopathy of the left eye in a 58-year
old woman with active Crohn's disease, presenting colo-anal and joint symptoms.
Spontaneously decreased bowel activity and local steroid treatment provided
symptom relief and incomplete decrease in volume of subepithelial elevations. We
discuss the clinical aspects, the epidemiologic factors, the pathogenic
mechanisms and the treatment of keratopathy in Crohn's disease.
PMID- 9759422
TI - [What is your diagnosis and treatment? Acute anterior uveitis without hypopyon].
PMID- 9759423
TI - [What would you do? Borderline ocular hypertension, visual field changes, and
papillary atrophy in a 65-year-old patient].
PMID- 9759424
TI - [Relaxing retinopathies and liquid perfluorocarbons].
AB - PURPOSE: To assess the long term anatomic and functional follow-up of large
relaxing retinotomies performed with liquid perfluorocarbon in severe
vitreoretinal proliferation surgery. METHODS: A large relaxing retinotomy (more
than 90 degrees) was realized in 40 eyes of 39 patients for anterior
vitreoretinal proliferation (30 rhegmatogen retinal detachments, 8 intraocular
foreign bodies, 2 ocular traumas). Follow-up was always longer than 6 months.
Vitreoretinal proliferation secondary to ischemic or inflammatory retinopathy
were excluded. The liquid perfluorocarbon was perfluorodecalin and was used for
all eyes, as well as final intraocular tamponade by silicon oil ended every
intervention. RESULTS: Sixty-seven % of patients had already had a former
vitrectomy, and 75% a retinal surgery. Mean size retinectomy was 170 degrees.
Nine patients underwent a new vitreoretinal procedure which included in 7 cases a
necessary new retinectomy. Silicon oil could be removed in 55%, after a mean
period of 6, 5 months. Mean time follow-up was 13 months. At the end of follow
up, 80% of retina were attached. Visual acuity remained low with 25% equal to
1/20 or more; 45% of eyes increased their acuity, 25% remained stable and 30%
worsened. Main complications were epimacular proliferation, keratopathy and
increased intraocular pressure. CONCLUSION: Relaxing retinotomies provide
satisfying anatomic results and allow a preservation of some visual function. The
use of liquid perfluorocarbons facilitates their realization. The initial size of
retinectomy should be sufficient.
PMID- 9759425
TI - [Anisometropia and presbyopia: prescription of progressive lenses, a new
approach].
AB - OBJECTIVE OF THE STUDY: To show that anisometropia does not absolutely preclude
the prescription of progressive lenses. MATERIALS AND METHODS: Forty-one
anisometropes and presbyopes were selected for a prolonged trial of visual
correction using progressive lenses. The congenital or acquired type of their
anisometropia and its particular form were also studied. Each patient was
submitted to a protocol comprising of a series of ophthalmologic and orthoptic
tests so as to evaluate the patient's subjective far and near refraction, with
measurement of phorias and of horizontal and vertical ductions, visual acuity,
and the quality of binocular vision while looking in different directions. A
preliminary trial of correction in actual situation was done in order to check
fusion in near vision. The entire range of tests was repeated two months after
the patient was provided with the lenses. The tolerance for progressive lenses
during the different activities of daily life was evaluated after the second and
the sixth months. RESULTS: Seven patients presenting an associated strabismus
were not provided with the lenses because the initial pre-lens trial revealed a
total inability to read within the near-vision zone. Among the 34 patients
provided with the lenses, 21 constantly wore their progressive lenses and said
that they were satisfied, 6 wore their progressive lenses during daily activities
but preferred to use their unifocal lenses for prolonged reading, and 7 abandoned
their progressive lenses because they could not tolerate them. Association with a
strabismus is not synonymous with an initial impossibility or with abandonment
because of the 27 patients who constantly wore their progressive lenses 9 were
strabismic. The best results were obtained in the age range of 45 to 52 years
old, for visual acuity for > 20/40, and in cases of congenital anisometropia with
intermittent or permanent unilateral neutralization. On the other hand, patients
presenting an acquired anisometropia, particularly postoperative, proved to be
poor candidates. CONCLUSION: Weak and strong anisometropia does not absolutely
preclude the prescription of progressive lenses except for certain strabismic
subjects with an abnormal lateral-oriented posture.
PMID- 9759426
TI - [Morphometry of the optic disc in Togolese patients with glaucoma or suspected
glaucoma. Preliminary study].
AB - PURPOSE: The aim of this study was to measure morphometric parameters of the
optic disc in Togolese glaucoma patients and suspects by the mean of the
millimetric scale of the slit lamp and the Goldmann contact lens. MATERIAL AND
METHOD: We selected 202 patients (393 eyes) with a mean age of 36.69 years +/-
15.33 (standard deviation); they were divided into 2 subgroups A (162
glaucomatous) and B (40 glaucoma suspects); direct reading of the slit lamp
millimetric scale and the Goldmann contact lens was used. RESULTS: In the group
A, the optic disc vertical diameter was 1.792 +/- 0.21 mm; the horizontal
diameter was 1.701 +/- 0.198 mm. In the group B, vertical disc diameter was 1.700
+/- 0.262 mm; the horizontal one was 1.662 +/- 0.190 mm. The vertical cup disc
diameter was 1.147 +/- 0.274 mm in the group A and 0.708 mm +/- 0.274 mm in the
group B. The neuroretinal area was 1.360 +/- 0.524 mm2 in group A and 1.786 +/-
0.467 mm2 in group B. CONCLUSION: This study using millimetric scale of the slit
lamp and the three mirrors Goldmann contact lens was easy, simple and useful
clinically. It could be helpful in conducting quantitative studies in countries
with low resources because this method is costless compared with others.
PMID- 9759427
TI - [Long-term results of cobalt 60 curietherapy for uveal melanoma].
AB - PURPOSE: To analyze 65 patients with uveal melanomas treated with cobalt plaque
therapy with regards to mortality, visual results and complications. PATIENTS AND
METHODS: Most of the melanomas were large (T3: 52.5%), with a mean largest
dimension of the base of 11 mm, and a mean thickness of 6 mm. Most of the tumors
were located in the choroid (95%), with an anterior margin behind the equator
(65%), and a posterior margin at less than 3 mm of the disc and/or of the macula
(69%). The plaque radiotherapy delivered a mean dose of 95 Gy to the tumor apex,
either with a cobalt plaque alone (51 cases), or in association with a ruthenium
plaque (14 cases). The mean follow up period was over 8 years. RESULTS: The local
control was achieved initially in 86% of the eyes. The estimated melanoma
specific survival rate was 83% after 5 years and 74% after 10 years. The main
parameter associated with the metastases was the largest dimension of the base (p
< 0.01). The eye was retained in 83% of the cases. The probability of keeping a
vision better than or equal to 0,1 was 39% after 5 years and 27% after 10 years.
The main parameter associated with the visual loss was the tumor size (p < 0.01).
The complications included cataract (39%), radiation retinopathy (34%), with
maculopathy (19%) and/or papillopathy (13.5%), vitreous hemorrhages (22%),
neovascular glaucoma (15%) and retinal detachment (12%). CONCLUSION: These
results supported the value of cobalt plaque radiotherapy in the management of
uveal melanomas.
PMID- 9759428
TI - [Update on a diagnostic test for choroideremia: the protein truncation test
(PTT)].
AB - PURPOSE: The aim of this study was to define the RT-PCR-PTT parameters for CHM
gene analysis and to evaluate its interest as a method for CHM mutation
screening. METHODS: The entire CHM coding region was reversed-transcribed in
three overlapping cDNA segments (RT-PCR) which were amplified and further
analyzed by PTT after in vitro transcription/translation. RESULTS: This strategy
enabled us to detect a truncated peptide in each of the 6 unrelated patients from
southern France who were investigated. The mutation was further characterized by
direct sequencing of the RT-PCR product. CONCLUSION: In CHM gene, all conditions
are present to make the RT-PCR-PTT strategy the method of choice for mutation
screening. As a result of the simplified protocol described in this study, the
families of the patients could benefit from accurate carrier-status assessment.
PMID- 9759429
TI - [Artificial trabeculum (MESH). Clinical and histological study in the rabbit].
AB - PURPOSE: Designed to avoid postoperative hypotony that often occurs after
trabeculectomy and to maintain long lasting filtration, the MESH is a thin porous
expended polytetrafluoroethylene (ePTFE) implant that mimics the physiological
meshwork. The aim of this study is to assess the tolerance, biocompatibility and
effectiveness of this device during 6 months in the rabbit. MATERIAL AND METHODS:
We used an ePTFE with about 5 microns pore size (Zytex). The head of the implant
is 3,0 mm wide and 1,5 mm long and fits in the anterior chamber. The tail is 2,0
mm wide and 3,0 mm long and fits in the subconjunctival space. The MESH is 250
microns thick. 24 Dutch pigmented rabbits were selected because their dark
pigmented iris contrasts with the ePTFE implant giving a better visualization.
All the animals were cared for in accordance with ARVO resolutions. Surgery was
performed on the right eye by the same surgeon (P.H.), the left eye serving as
control for IOP measurements. The animals were distributed in 3 groups: one with
MESH alone (MESH), one with MESH and Mitomycin C (MMC), one with MESH and 5-FU (5
FU). Follow-up was performed every week (W) during 6 months including IOP
measurement, slit lamp observation, photography and bleb assessment. Histological
study was done at POD 0, 15, 30, 90 and 180 one eye in each group. Student t test
and alternate Welch t test were used for statistics. RESULTS: Filtering bleb: no
bleb was visible before W3. A bleb was found between W3 and W6, decreasing
between W6 and W9 with no more change after W10. The MESH implant: no change
appears in the color of the MESH during the study. Some iris pigments or
synechiae were seen in some cases. No extrusion occurred. Intraocular pressure:
IOP was lower than in the control eye. The statistical analysis showed a
significant lower pressure for the MESH alone at W5 (p = 0.0069), for the 5-FU
group at W1 (p = 0.0326), W2 (p = 0.0488), W4 (p = 0.0312). With Mitomycine C we
found very significant results at W1 (p = 0.0073), W2 (p = 0.0136), W4 (p =
0.0497), W9 and W11 (p = 0.0174). After W12 the groups were joined and IOP was
significantly decreased at W17 (p = 0.0376) and W23 (p = 0.0462). Histology
confirmed the correct position of the MESH, its biocompatibility and its ability
to drain aqueous humor even if there is colonization of the pores by fibroblast
like cells. CONCLUSION: The present study has shown that the filtering bleb
appeared after 3 weeks without major hypotony. The material was integrated only
in the intrascleral tunnel and was stable. After 6 months the Mesh was well
tolerated. The new concept has a simple surgical technique, less invasive than
trabeculectomy and required less surgical time. This technique reduced IOP and
produced long survival blebs in rabbits. This device appears suitable for the
surgical treatment of open angle glaucoma.
PMID- 9759430
TI - [Postoperative ptosis: etiopathogenesis, clinical analysis, and therapeutic
management. Apropos of a series of 43 cases].
AB - PURPOSE: Acquired postoperative ptosis (PP) are difficult to situate in the
current classification of ptosis. Assessement of the mechanisms, the clinical
features and the possible treatments of these PP would suggest a new
classification of ptosis. MATERIAL AND METHODS: Among 260 cases of surgically
corrected ptosis, 43 cases of PP (16.5%) were detected and analyzed. RESULTS:
Forty cases of PP were eligible for this study. Their responsible mechanisms were
aponeurotic (57.5%), mixed (aponeurotic and/or myogenic and/or neurogenic)
(27.5%) and myogenic (15%). PP was assessed in most cases as being mild (77.5%)
and the levator's muscle contraction was most often mildly impaired (77.5%). In
these cases, surgical procedure was performed: levator aponeurosis disinsertion
repair (85%), Fasanella-Servat procedure (2.5%), frontalis sling (2.5%) and other
surgical procedure with synthetic materials (10%). Postoperative complications
included 1 case of persistent lid edema and 4 cases of spontaneous suture
rupture. Six patients (15%) were secondarily reoperated: 2 for overcorrection
(5%) and 4 for undercorrection (10%). The general outcome was good in 90% of
cases, insufficient in 5% of cases and unsatisfactory in 5% of cases. CONCLUSION:
This study confirms the previously described features of the PP: onset after
anterior surgery procedures of usually moderate ptosis, induced by an aponeurotic
defect mechanism in most cases. The treatment was exclusively surgical: anterior
reinsertion of the levator aponeurosis. For better management, we suggest a new
ptosis classification: aponeurotic, myogenic, neurogenic and mixed (aponeurotic
and/or myogenic and/or neurogenic) and false or pseudo-ptosis.
PMID- 9759431
TI - [Small retinal, cochlear, and cerebral infarctions in the young patient, "SICRET"
syndrome of Susac syndrome].
AB - A 22-year-old-lady presented with multiple occlusions of the branches of the
central retinal artery, accompanied by neuro-encephalic disorders and deafness.
This triad is known as SICRET Syndrome (Small Infarction of Cochlear, Retinal and
Encephalic Tissue). This rare syndrome, as well referred to as Susac syndrome,
affects only the women and the three tissues mentioned above: eye, ear, brain.
The course was characterised by a series of partially regressive evolutive steps.
A remission had been obtained since two years with immuno-supressor and anti
coagulant therapy. The neuro-encephalic and cochlear disorder regressed in
contrast to the severe sequel on the right eye.
PMID- 9759432
TI - [Optic neuromyelitis and bilateral acute retinal necrosis due to varicella zoster
in a patient with AIDS].
AB - We report a case of bilateral acute retinal necrosis (ARN) following an acute
optic neuromyelitis (AONM) in an immunodepressed patient (T CD4 lymphocyte count
under 50/mm3) suffering from acquired immunodeficiency syndrome (AIDS). Despite
the medical treatment the evolution led to blindness by bilateral total retinal
detachment. The neuro-ophthalmological features occurred prior to the retinal
manifestation, and the acute optic neuromyelitis occurred after a spreading
zoster. The varicella-zoster virus (VZV) seemed to be involved because of
recurring cutaneous zoster, spreading of this zoster just before the AONM,
previous reports showing a link between VZV and AONM, and VZV and ARN. However,
our patient had first an AONM responding well to corticosteroid therapy following
one month later by an ARN leading to blindness despite the antiviral treatments
received as soon as possible. There is a chronical viremia+ in immunodepressed
patients with recurring and spreading zoster. The rupture of the hemato
encephalic barrier observed in AONM could facilitate the invasion of the eye by
the virus, leading to an ARN. This hypothesis could explain the two complications
due to the VZV, the AONM and the ARN, the first one is of dysimmunitary origin
and the second one could probably result of a direct viral attack of the retina.
This should incite to treat as soon as possible each retrobulbar optic neuritis
in patients with AIDS, especially if past history of zoster.
PMID- 9759433
TI - [Candida chorioretinitis in drug addicts. Apropos of 2 cases].
AB - We report two cases of candidal chorioretinitis occurring to two friends who
abused of intravenous crack using the same syringe . An endophthalmitis "a
minima" due to a therapeutic delay arose in one patient, when a rare spontaneous
healing happened to the second patient. In both cases, an epiretinal membrane is
noted after the lesions scarred. Ocular candidal infection is a typical
complication occurring to intravenous drug addicts. The visual prognosis depends
not only on early diagnosis and treatment, but also on a strict follow-up because
late complications are frequent in spite of the healing of initial lesions.
PMID- 9759434
TI - [Postoperative choroid detachment following microsurgery for rhegmatogenous
retinal detachment].
AB - PURPOSE: To evaluate the incidence, predisposing and prognosis factors of post
operative choroidal detachment after microsurgery of rhegmatogenous retinal
detachment. MATERIALS AND METHODS: We conducted a retrospective study on a series
of 595 consecutive rhegmatogenous retinal detachments referred before any
previous failed surgery. Univariate statistical analysis of the data was
conducted with evaluation of the odds ratio. RESULTS: Postoperative choroidal
detachment developed in 23/595 eyes (3.8%). Significant predictive factors for
post operative choroidal detachment included patient's age over 50 years, male
gender, pseudophakia, retinal detachment higher than 90 degrees and giant tears.
We found no correlation between postoperative choroidal detachment and the
retinopexy method, subretinal fluid release and the type of scleral buckling
procedure (segmental versus incercling). Postoperative choroidal detachment did
not influence at a statistically significant level the postoperative outcome.
Permanent retinal reattachment was achieved in 20 of the 23 eyes (87%) with
postoperative choroidal detachment, and 564 of 572 eyes (93%) with no post
operative choroidal detachment (p > 0.05). Postoperative PVR occurred in 3 of the
23 eyes (13%) with postoperative choroidal detachment and 3 of the 572 eyes (5%)
with no postoperative choroidal detachment (p > 0.05). The postoperative visual
outcome was not influenced by the occurrence of postoperative choroidal
detachment. CONCLUSION: Postoperative choroidal detachment after retinal
detachment microsurgery is a rare complication. Its prognosis is good. The
occurrence of postoperative choroidal detachment does not influence the
postoperative outcome of retinal detachment microsurgery.
PMID- 9759435
TI - [Combined phacoemulsificaion/membrane resection and macular edema].
AB - PURPOSE: To evaluate the occurrence of macular edema (ME) after epiretinal
membrane resection, managed either with simple vitrectomy or with combined
vitrectomy and phacoemulsification. MATERIAL AND METHODS: Two groups of 12
patients had a vitrectomy for epiretinal membrane associated or not to a
phacoemulsification. A fundus fluorescein angiography was performed pre and
postoperatively and at least 3 months after the surgery. RESULTS: In the group of
patients who had a simple vitrectomy, a ME was observed in 50% of the cases
preoperatively and in 25% of the cases at the end of follow-up. In 3 cases,
preoperative ME was worsened after the surgery. In the group of patients who were
treated by a combined vitrectomy and phacoemulsification, a ME was observed in
25% of the cases preoperatively and in 50% of the cases at the end of follow-up.
A de novo ME was observed in 3 cases. CONCLUSION: Combined vitrectomy and
cataract surgery could allow a rapid recovery of visual acuity but might increase
the occurrence of ME.
PMID- 9759436
TI - [Rupture of the hemato-ocular barrier, studied by fluorophotometry, in uveal
melanoma patients. Preliminary results].
AB - PURPOSE: To evaluate the use of intravenous vitreous fluorophotometry in
assessment of the blood-aqueous barrier in eyes with uveal melanoma. METHOD:
Vitreous fluorophotometry was performed before treatment in 14 patients with
uveal melanoma. Both eyes of patients were examined, and fifteen control healthy
patients were examined between November 1996 and December 1996 at the department
of ophthalmology of Bicetre hospital. RESULTS: Tumors with height > 6 mm and
serous retinal detachments were accompanied by marked alterations of the blood
aqueous barrier, vitreous fluorophotometry showed diffusion of dye in posterior,
mid and anterior vitreous: 2.99 ng/ml in the posterior vitreous and 5.20 ng/ml in
the anterior vitreous. The posterior vitreous fluorescence at 60 minutes in the
control eyes was 1.43 ng/ml and 1.30 ng/ml in the anterior vitreous. Diffusion of
dye was present in the posterior vitreous in patients with tumor height less than
6 mm: 2.38 ng/ml (1.43 ng/ml in control eyes) at 60 minutes. CONCLUSIONS:
Fluorophotometry provides a method for the assessment of the blood-aqueous ocular
barrier in eyes with choroidal melanoma.
PMID- 9759437
TI - [Predictability of amblyopia in ametropic children. Apropos of 96 cases].
AB - PURPOSE: The aim of this cross-sectional retrospective study was to analyze the
predictability of amblyopia in children with myopic and hyperopic unilateral and
bilateral ametropia. MATERIALS AND METHODS: One hundred and sixty two eyes of 96
children, (mean age: 8.6 years), were included in this work. Mean visual acuities
and significant refractive errors were estimated for all the cases. The frequency
of amblyopia and strabismus was studied in cases without amblyopia and in cases
with medium and high grade amblyopia. RESULTS: Mean visual acuities were
significantly higher in cases of bilateral myopia (p < 0.001) and hyperopia (p <
0.05) compared with unilateral ametropia. The frequency of myopic eyes (p <
0.01), eyes with high grade of myopia (p < 0.002) and anisomyopic eyes (p <
0.001) was significantly higher in cases of high amblyopia compared with cases
without amblyopia. Strabismus (p < 0.05) were also significantly more frequent in
cases of high amblyopia as well as in cases of myopic eyes (p < 0.01). Moreover,
in the group of high amblyopia, 6 cases (6/7) had developed an intolerance for
contact lenses. CONCLUSIONS: The risk of developing high grade amblyopia appeared
significantly associated with unilateral medium and high level myopia. Strabismus
and difficulties with good correction of anisometropia by contact lenses or
spectacle appeared to be predisposing factors. This observation would suggest the
indication of refractive surgery might be useful in these particular cases. To
conclude, this study emphasizes the importance of early treatment of ametropia to
reduce the incidence of amblyopia in children.
PMID- 9759438
TI - [Oculomotor risk after trans-palpebral bony decompression for thyroid-related
orbitopathy].
AB - PURPOSE: To study oculomotor disorders after transpalpebral bony orbital
decompression (TPBOD) for dysthyroid orbitopathy. Pathophysiology, risk factors,
preventive and therapeutic care were examined. MATERIAL AND METHODS: Forty-four
patients were included in this retrospective study (76 orbits). Thirteen patients
underwent surgery for severe orbital inflammation or optic neuropathy and 31 for
cosmetic rehabilitation. 21 previously had orbital radiotherapy. Class IV of
NOSPECS classification, primary position of gaze, diplopia and Lancaster
coordimetry were studied comparatively pre and postoperatively. RESULTS: Diplopia
appeared in 23.6% of the cases without deviation before surgery (tropia or phoria
tropia). Predictive factors were age and amblyopia whereas amount of
retrodisplacement of the globe and radiotherapy were not. Lack of oculomotor
restriction did not prevent from diplopia but may decrease its incidence.
Unilateral decompression is more likely to create a vertical disorder.
Pathophysiology is discussed. CONCLUSION: Oculomotor disorders can be explained
by several mechanisms. Some of them can be prevented. Each patient should be
aware of the risk of diplopia.
PMID- 9759440
TI - [Retraction nystagmus of vascular origin].
AB - We report a case of a 42-year-old woman who was referred for diplopia. She
appeared to have a convergence retraction syndrome and loss of vertical gaze. The
clinical course led to a diagnosis of thromboembolic cerebrovascular event in the
region of the posterior commissure on the basis of risk factors such as smoking
and oral contraceptive use. The final outcome was rapidly favorable.
PMID- 9759439
TI - [Retinal complications in AIDS patients at the Lome (Togo) University Hospital].
AB - BACKGROUND: The purpose of this study was to describe retinal complications
observed in patients presenting with AIDS at Lome teaching hospital. MATERIAL:
All patients who met WHO AIDS clinical case diagnostic in Africa, admitted for
various signs in hospital, were followed between December 1996 and May 1997 for
ocular examinations. RESULTS: We surveyed 94 patients; 41 (43.6%) had retinal
lesions. Retinal complications were cotton whool spots (30 cases), retinal
hemorrhages (4 cases), papilloedema (4 cases), cytomegalovirus retinitis (8
cases). Mortality in patients with retinal complications occurred 10 months after
the clinical diagnosis of AIDS. CONCLUSION: This study has found a high retinal
morbidity contrasting with other studies in Africa. This could be explained by
the longer period of follow-up larger than in previous similar studies.
PMID- 9759441
TI - [Werner syndrome. Apropos of a case].
AB - A 26 year-old woman, whose parents were consanguineously married, was admitted to
our center because of bilateral juvenile cataract. The patient exhibited short
stature, sclerodermalike appearance of the skin with a typical bird-like facies,
thinning and graying of hair, high pitched voice and hypogonadism. Werner's
syndrome, was diagnosed. History, pathogeny, clinical features, diagnosis and
cataract surgery are discussed.
PMID- 9759442
TI - [Isolated ocular melanosis. Apropos of a case].
AB - A case of an eighteen month child with ocular melanocytosis is reported. The
authors describe clinicopathological features of the affection. Ocular
melanocytosis is a neural crest disorder more frequently found in pigmented
populations. Differential diagnosis are naevus of Ota, blue sclera disease and
scleritis. The risk of malignant degeneration especially in caucasian people
explain that patient should be followed-up at regular intervals.
PMID- 9759443
TI - [Cornea plana and severe ametropia].
AB - Cornea Plana is a bilateral and asymmetric congenital malformation of the corneo
scleral shape. Corneo-scleral lenses are said to be the preferential treatment.
We reported the case of a 20-year-old woman, whose Cornea Plana was diagnosed at
birth, with high hypermetropia and well-corrected with routine spectacles since
she was 6 months old.
PMID- 9759444
TI - [Caruncular melanoma. Apropos of clinical case].
AB - The clinicopathologic case of a 69-year-old-female patient with a big caruncular
melanoma is reported. Tumor was excised surgically and underwent external
conventional radiation therapy with no recurrence two years later. Histopathology
endorsed the clinical diagnosis and thickness of the tumor measured 5.5 mm. The
bad prognosis of the caruncular location was reinforced by the tumor thickness. A
better knowledge of conjunctival melanomas characteristics might allow an earlier
diagnosis and a better prognosis as irradiation following surgical treatment
appears efficient on unifocal limited melanomas.
PMID- 9759446
TI - [Pigmented basal cell carcinoma of the eyelid. Apropos of a clinical case].
AB - A clinico-pathologic case of a 83-year-old female patient with a deeply pigmented
inferior lid tumor is reported. The histopathological study of the tumor
demonstrated a pigmented basal cell carcinoma. Numerous different tumors may
affect the eyelids, melanocytic or not in nature. True melanomas are infrequent
compared with the numerous other pigmented tumors, which always need a
histological analysis.
PMID- 9759447
TI - 7th European Stroke Conference. Edinburgh, United Kingdom, May 27-30, 1998.
Abstracts.
PMID- 9759448
TI - 3rd Meeting of the European Society of Neurosonology and Cerebral Hemodynamics.
Glasgow, United Kingdom, May 24-26, 1998. Abstracts.
PMID- 9759449
TI - [The 15th Congress of the Ukrainian Physiological Society. Donets'k, Ukraine. May
12-15, 1998. Abstracts].
PMID- 9759445
TI - [Actinic keratosis of the conjunctiva. Apropos of a clinical case].
AB - We report a slowly progressive and whitish limbal conjunctival tumor that
occurred in a 73-year-old man. An excisional biopsy specimen of this conjunctival
tumor was submitted for histopathologic evaluation. The diagnosis of conjunctival
actinic keratosis was based on following cellular abnormalities: epithelial
hyperplasia acanthosis, keratosis or parakeratosis with discrete papillomatosis
and some atypia. The basement membrane was intact. An area of elastotic
degeneration in the subtantia propria, was considered as one of the
characteristic features of this conjunctival precancerous condition related to
excessive sun exposure. By hybridization in situ, the detection of human
papilloma virus (HPV) was negative. Keratosis actinic needs to be distinguished
from other precancerous conditions showing similar clinical features such as
dysplasia and carcinoma in situ appearing to affect the prognosis.
PMID- 9759450
TI - 3rd National Congress of the Italian Society of Medical Andrology. Rome, Italy, 2
3 April 1998. Abstracts.
PMID- 9759451
TI - 3rd Joint meeting of the European Society for Dermatological Research, Japanese
Society for Investigative Dermatology, Society for Investigative Dermatology,
Cologne, Germany, 7-10 May 1998. Abstracts.
PMID- 9759452
TI - 25th Annual meeting of the European Thyroid Association. Athens, Greece, May 30
June 3, 1998. Abstracts.
PMID- 9759454
TI - XII Panamerican Congress of Rheumatology. Montreal, Quebec, Canada. June 21-25,
1998. Abstracts.
PMID- 9759453
TI - Canadian Society of Otolaryngology-Head and Neck Surgery 52nd annual meeting.
Montreal, Quebec, Canada. June 14-17, 1998. Abstracts.
PMID- 9759455
TI - 4th International Conference on Functional Mapping of the Human Brain. Montreal,
Quebec, Canada. June 7-12, 1998. Abstracts.
PMID- 9759456
TI - 1st Combined International Symposium on Ocular Immunology and Inflammation.
Amsterdam, The Netherlands, June 27-July 1, 1998. Abstracts.
PMID- 9759457
TI - XX Congress of the Italian Society of Parasitology. Rome, 17-20 June, 1998.
Abstracts.
PMID- 9759458
TI - 82nd Meeting of the German Society of Pathology. Kassel, Germany. 3-6 June 1998.
Abstracts.
PMID- 9759459
TI - Cumulative indexes-volumes 51-75.
PMID- 9759460
TI - 49th Annual meeting of the German Society of Neurosurgery, Hannover, June 12-16,
1998. Abstracts.
PMID- 9759461
TI - [Radiation protection in the European Community and in Germany].
AB - During the last few months, administrations of both the European Community and
Germany have brought up several recommendations and changes concerning radiation
protection. The European changes must become national law by 13th May, 2000. The
changes focus on better protection of children and pregnant women. When
performing X-ray examinations, strict indications will have to be observed.
PMID- 9759462
TI - [Pleural drainage in acute thoracic trauma. Comparison of the radiologic image
and computer tomography].
AB - PURPOSE: Estimation of chest tube placement in patients with thoracic trauma with
regard to chest tube malposition in chest radiography in the supine position
compared to additional computed tomography of the thorax. MATERIAL AND METHODS:
Apart from compulsory chest radiography after one or multiple chest tube
insertions, 31 severely injured patients with thoracic trauma underwent a CT scan
of the thorax. These 31 patients with 40 chest tubes constituted the basis for
the present analysis. RESULTS: In chest radiography in the supine position there
were no chest tube malpositions (n = 40); In the CT scans 25 correct positions, 7
pseudo-malpositions, 6 intrafissural and 2 intrapulmonary malpositions were
identified. Moreover 16 sufficient, 18 insufficient and 6 indifferent functions
of the chest tubes were seen. CONCLUSION: In case of lasting clinical problems
and questionable function of the chest tube, chest radiography should be
supplemented by a CT scan of the thorax in order to estimate the position of the
chest tube.
PMID- 9759463
TI - [Multi-project angiography in the imaging of cerebral aneurysm].
AB - In spite of procedures such as CT angiography, MR angiography, and rotation
angiography, panangiography is still indispensable in therapeutic planning for
cerebral aneurysms. It is the only method that provides exact details about the
size, anatomic localization, and multiplicity of aneurysms as well as relation to
surrounding vessels, the presence of an aneurysmal neck, and for the evaluation
of the collateral circulation required to answer the question if endovascular
therapy is possible. In addition, panangiography still exhibits the highest
selectivity in the detection of cerebral aneurysms.
PMID- 9759464
TI - [3-phase spiral CT of the liver, Value of non-contrast arterial and portal venous
studies in the diagnosis of focal liver lesions].
AB - PURPOSE: To assess the value of noncontrast, arterial and portal venous phase of
triphasic helical CT in detecting and characterising focal liver lesions.
MATERIAL AND METHODS: 120 patients with focal liver disease underwent triphasic
helical CT examinations with a collimation of 6.5 mm at a table feed of 6.5 mm/s.
The liver scans were obtained before the administration of 120 ml of non-ionic
contrast material (flow 2 or 3 ml/s), at the arterial phase, and at the portal
venous phase (20 s, respectively 60 s after injection). Patients were divided
into four groups according to the underlying disease and enhancement pattern. The
studies were evaluated retrospectively. RESULTS: A total of 269 lesions was seen.
The noncontrast phase (NCP) revealed 86% of lesions, the arterial phase (AP) 95%
and the portal venous phase (PVP) 91%. In the first group of hypovascular lesions
(colorectal carcinoma) all lesions (73/73) were detected in the PVP. In the
second group of hypervascular lesions (breast cancer, melanoma) the combination
of AP and PVP revealed 73 of 74 lesions. In the third group of patients with
unknown primary and detected lesions by sonography all 89 lesions were detected
with the combination of AP and PVP. In the fourth group of patients with
cirrhosis 3 of 33 lesions were detected exclusively during the AP and 3 other
lesions exclusively during the NCP. To make a definitive diagnosis of focal liver
lesions the value of the three phases was as follows: to characterise lesions the
PVP was sufficient in 62%, the combination of PVP and AP in 27%, and the
combination of all three phases in 11%. CONCLUSIONS: If hypovascular lesions are
suspected examination during PVP is sufficient. In cases of hypervascular lesions
and lesions of unknown primary AP and PVP should be combined. Unenhanced scans
are of additional diagnostic value only in patients with liver cirrhosis.
PMID- 9759465
TI - [MRI in typical and atypical aortic dissection].
AB - PURPOSE: To determine the value of MRI in typical and atypical aortic
dissections. METHODS: MRI investigations on 16 patients with aortic dissections
were analysed retrospectively; for 8 patients CT investigations carried out at
almost the same time were available for comparison. RESULTS: In all cases the
diagnosis of aortic dissection was possible from MRI and CT. If a dissection
membrane and a double lumen were present these were detected in all patients by
both methods. In three patients with atypical dissections, only an asymmetrical
abnormal wall thickening as sole sign for the presence of an aortic dissection
was seen. A differentiation between true and false lumen was possible in 16 of 17
MRI investigations and in 5 of 8 CT investigations on the basis of differing
blood flow velocities or, respectively, the detection of a thrombus in the false
lumen. The relationship of the dissection membrane to the large aortic branches
as well as the determination of the branch vessel origin with regard to true or
false lumen could be evaluated better with MRI than with CT. CONCLUSIONS: Thus
MRI has a significant role in the diagnosis and follow-up of aortic dissections.
The advantage in comparison to the alternative spiral CT technique is, in
addition to the absence of radiation exposure, the better analysis of the extent
of the dissection as a result of the multi-planar slice orientation (especially
in the region of the aortic arch and the arch vessel origins) without the
necessity to administer iodine-containing contrast media.
PMID- 9759466
TI - [Clinical aspects of image quality and doses in gated pulsed imaging].
AB - PURPOSE: The relations between image quality in last image hold images and dose
in grid controlled fluoroscopy in comparison to the continuous mode need to be
characterised and recommendations for the clinical application of this technique
should be given. MATERIAL AND METHODS: Spatial resolution, signal-noise ratio
and, contrast-detail visibility were evaluated by phantom measurements in grid
controlled pulsed and continuous fluoroscopy. Dose was measured at the image
intensifier entrance. Image quality of last image hold (LIH) images of clinical
examinations was graded in relation to single shot exposures. RESULTS: Signal
noise ratio and contrast-detail visibility depend on the dose per puls. Spatial
resolution and contrast-detail visibility in grid controlled fluoroscopy are
superior than to in the continuous mode. Image quality of the LIH images from the
grid controlled fluoroscopy was improved. Radiation exposure could be reduced to
10-46%. CONCLUSIONS: Combinations of puls-dose and -frequency are recommended for
achieving extensive dose reduction and improved image quality of LIH images.
PMID- 9759467
TI - [Radiation-induced osteonecrosis of the pelvic bones vs. bone metastases--a
difficult differential diagnosis].
AB - BACKGROUND: Since the introduction of megavoltage radiation therapy radiation
osteitis has become a rare event and may be easily mistaken for bone metastases.
A case of radiation osteitis is reported and diagnostic features are discussed.
CASE REPORT: A 70 year-old female patient underwent rectum resection for rectum
cancer and was given standard adjuvant therapy consisting of irradiation of the
tumor site and lymph nodes in the pelvis with 18 MeV photons, boxfield technique
up to 50.4 Gy and chemotherapy with 5-FU. Eight months later she complained of
severe lower back pain. Plain radiographs and CT revealed osteolytic lesions in
the ileosacral joints and os sacrum which appeared as circumscript areas of
signal loss in MRI (T1-weighted sequence). A soft tissue mass was not detected.
CT-guided biopsy excluded bone metastases. CONCLUSION: Characteristic features of
radiation osteitis are spongiosa destructions initially in weight-bearing bones
within the radiation field, namely the ileosacral joints, and the lack of
pathologic soft tissue mass. False treatment, i.e. radiation for bone metastases,
should be avoidable.
PMID- 9759468
TI - [Pseudo-rupture of the femoral artery following balloon angioplasty].
AB - Following PTA of a superficial femoral artery stenosis, painful swelling of the
vastus medialis muscle occurred at mobilization of the patient 24 hours after the
intervention. Duplex sonography and angiography revealed bleeding from a muscular
branch of the SFA. The complication was successfully treated by embolization.
PMID- 9759469
TI - [Barium aspiration with fatal outcome].
AB - A female patient died after aspiration of a barium-containing contrast medium as
a result of ARDS in spite of intensive medical care. In cases of aspiration, the
degree of aspiration should be documented by X-ray as soon as possible in order
to decide upon the extent of specific suction measure. Lethalities after
aspiration may be more frequent than can be assumed from the reports in the
literature.
PMID- 9759470
TI - [Bullet embolism in the right pulmonary artery].
AB - We report about a bullet embolus in the middle lobe pulmonary artery (a patient
who was sent for a routine-chest-film preoperatively). The patient, 74 years old,
was hit by a bullet in localization of the left masseteric region during world
war II. The bullet entered the left Vena jugularis and was embolised into the
middle lobe pulmonary artery (shock-position). By the means of CT-curved
reformations we could localize the bullet (2 x 0.7 cm) in the middle lobe
pulmonary artery and diagnosed a lobar fibrosis as a sequel of the focal
hypoxemia.
PMID- 9759471
TI - Cytogenetic and molecular investigations of Y chromosome sequences and their role
in Turner syndrome.
AB - It has been proposed that all live born females with Turner syndrome carry a cell
line containing two sex chromosomes, which may be present at a low level of
mosaicism (Hook & Warburton, 1983; Hassold et al. 1985; 1988; Connor & Loughlin,
1989). If the second sex chromosome is a Y, these patients are at risk of
developing gonadoblastoma. In this study, 50 patients found to have a 45,X
karyotype by conventional cytogenetic analysis, were screened by the polymerase
chain reaction (PCR), for the presence of Y chromosome sequences. Two patients
were positive for six of the eight Y chromosome loci tested and additional
cytogenetic analysis confirmed the presence of a marker chromosome, in 8% and 3%
of cells respectively. Fluorescence in situ hybridization (FISH) was used to
confirm that the markers were of Y chromosome origin and helped to elucidate
their structure. In addition, four other patients were found to have a Y
chromosome by initial routine cytogenetic analysis. FISH, in conjunction with
PCR, elucidated the structure of the Y chromosomes. This study illustrates the
value of using a combination of cytogenetic and molecular techniques, to identify
Y chromosome sequences in Turner syndrome.
PMID- 9759472
TI - A splicing mutation of the RHAG gene associated with the Rhnull phenotype.
AB - Rhnull is a syndrome serologically characterized by the deficiency of all Rh
antigens on human red blood cells. Rhnull is divided into two types: regulator
and amorph. Recently, Cherif-Zahar et al. proposed that the RHAG gene encoding
the Rh50 glycoprotein is a candidate for inducing regulator type Rhnull. We
investigated both the RH and RHAG genes in an Rhnull individual. The
reticulocytes from the propositus had RHD, RHcE, and RHCe transcripts without any
mutation. However, the sequence analysis of RHAG cDNA showed a deletion of 122 bp
from nucleotide 946 to 1067. This deletion was revealed to be due to a homozygous
splicing mutation, which is a single base substitution at the consensus sequence
of the splicing acceptor site (AG-->AT). The mutation appeared to break the 'GT
AG' splicing rule and to cause 122 bp exon skipping accompanied by a frameshift.
This study confirms that the RHAG gene is the most likely candidate for the
'regulator' gene of Rhnull cases.
PMID- 9759473
TI - Age-related changes of the 3'APOB-VNTR genotype pool in ageing cohorts.
AB - The analysis of seven different age cohorts (697 individuals from 10 to 109 years
old) revealed age-related changes in the 3'APOB-VNTR genotype pool. By recoding
the 3'APOB-VNTR alleles into three size-classes (small, S, 26-34 repeats; medium,
M, 35-39 repeats; large, L, 41-55 repeats), an age-related convex trajectory of
the frequency of SS homozygotes was found. The frequency of SS in the genotype
pool increased from the group aged 10-19 years (3.06 +/- 1.74%) to that aged 40
49 years (8.51 +/- 4.07%). Then it declined reaching the minimum value in
centenarians (1.58 +/- 0.90%). The observed trajectory is in agreement with that
expected by assuming crossing of mortality curves relevant to subgroups of
individuals having different genotypes.
PMID- 9759474
TI - HLA evidence for the lack of genetic heterogeneity in Basques.
AB - To examine the possible internal heterogeneity within the Basque population, nine
samples typed for several HLA loci were compiled and HLA-A, B, C and DR loci were
analysed. First, the shared features of HLA in Basques were analysed by principal
component analysis and genetic distances. Two major Basque dialect groups
('French' and 'Spanish') were considered. FST statistics were computed and
corrected for sampling intensity. The dialectal and political division did not
seem to differentiate these two groups genetically. Analysis of Molecular
Variance also failed to show consistently significant genetic variance components
between French and Spanish Basques. Thus, in this particular example, linguistic
diversity does not seem to correlate with a genetic stratification.
PMID- 9759475
TI - Diversity in protein, nuclear DNA, and mtDNA in South Amerinds--agreement or
discrepancy?
AB - Two sets of markers and populations were considered in this study: (a) the
variability at 17 protein loci and in the sequences of the first hypervariable
segment of the mitochondrial DNA (mtDNA) were compared in 10 South American
Indian tribes, in a total 3016 and 241 individuals, respectively; and (b) a
triple comparison was made, in relation to 17 protein, mtDNA and six
hypervariable tandem repeat loci in four Brazilian Indian tribes, involving 1567,
56 and 194 persons, respectively. Both the intrapopulational diversities and the
population relationships obtained in these groups with these different sets of
markers showed no significant correlation. High levels of heterogeneity were
observed both at the protein and hypervariable individual loci, as well between
mtDNA sites. The different positions observed for the Yanomama (but not for the
other nine tribes) in the trees which summarized the protein and mtDNA data
suggest some degree of asymmetric interchange related to sex between them and
neighbouring tribes.
PMID- 9759476
TI - The role of consanguinity and inbreeding as a determinant of spontaneous abortion
in Karachi, Pakistan.
AB - The effect of consanguinity and inbreeding on spontaneous abortion is assessed
with the help of data from a population-based study conducted in four squatter
settlements of Karachi, Pakistan. The analysis is based on 4966 pregnancy records
belonging to 873 women. Results of the multivariate analysis show that both
consanguinity and inbreeding were independent risk factors for spontaneous
abortion despite undertaking control for other biological and socio-demographic
factors that could confound the association. The combination of fetal and
parental inbreeding led to a greater likelihood of a pregnancy ending in
spontaneous abortion than one generation of inbreeding alone.
PMID- 9759477
TI - Hidden linkage: a comparison of the affected sib pair (ASP) test and
transmission/disequilibrium test (TDT).
AB - I compare the transmission/disequilibrium test (TDT) and affected sib pair (ASP)
test under a general algebraic model describing a bi-allelic disease locus.
Assuming linkage to a bi-allelic marker, I derive two binomial probabilities, one
for parental allele 'transmission' (Pt) which determines the magnitude of the TDT
chi 2 statistic (chi 2tdt), and a second for identity-by-descent (ibd) marker
allele 'sharing' (Ps) which determines the magnitude of the ASP test statistic
(chi 2asp). I also consider the ASP test applied to a completely polymorphic
marker and demonstrate that the probability of ASP marker allele sharing (Ps) is
identical to Ps observed for a bi-allelic marker in equilibrium with the disease
locus. I present a general framework for determining the power of the TDT and ASP
test based on expressions for Pt, Ps and the proportion (H/F) of ascertained
parents who are informative at the marker. Two previous analytic investigations
of TDT power based on the work of Ott (1989), and Risch & Merikangas (1996) are
shown to be special cases of this general framework. In addition, I show the
relationship between the framework I present and a third analytic investigation
of TDT power for multi-allelic markers based on the work of Sham & Curtis (1995).
PMID- 9759478
TI - Characterization of polymorphisms at the 11 beta-hydroxylase (CYP11B1) locus.
AB - Four sequence variants in the 11 beta-hydroxylase (CYP11B1) gene are reported.
One of the sequence changes occurs in exon 1 and is in linkage disequilibrium
with a second variant in intron 3. The other two changes occur at adjacent
nucleotides in intron 1. The finding of easily demonstrable, intragenic variants
will be beneficial to the study of the role of the CYP11B1 and the adjacent
aldosterone synthase (CYP11B2) gene in hypertensive disease.
PMID- 9759479
TI - An accidental biochemist.
PMID- 9759480
TI - HIV-1: fifteen proteins and an RNA.
AB - Human immunodeficiency virus type 1 is a complex retrovirus encoding 15 distinct
proteins. Substantial progress has been made toward understanding the function of
each protein, and three-dimensional structures of many components, including
portions of the RNA genome, have been determined. This review describes the
function of each component in the context of the viral life cycle: the Gag and
Env structural proteins MA (matrix), CA (capsid), NC (nucleocapsid), p6, SU
(surface), and TM (transmembrane); the Pol enzymes PR (protease), RT (reverse
transcriptase), and IN (integrase); the gene regulatory proteins Tat and Rev; and
the accessory proteins Nef, Vif, Vpr, and Vpu. The review highlights recent
biochemical and structural studies that help clarify the mechanisms of viral
assembly, infection, and replication.
PMID- 9759481
TI - Sphingolipid functions in Saccharomyces cerevisiae: comparison to mammals.
AB - Many roles for sphingolipids have been identified in mammals. Available data
suggest that sphingolipids and their intermediates also have diverse roles in
Saccharomyces cerevisiae. These roles include signal transduction during the heat
stress response, regulation of calcium homeostasis or components in calcium
mediated signaling pathways, regulation of the cell cycle, and functions as
components in trafficking of secretory vesicles from the endoplasmic reticulum to
the Golgi apparatus and as the lipid moiety in many glycosylphosphatidylinositol
anchored proteins. S. cerevisiae is likely to be the first organism in which all
genes involved in sphingolipid metabolism are identified. This information will
provide an unprecedented opportunity to determine, for the first time in any
organism, how sphingolipid synthesis is regulated. Through the use of both
genetic and biochemical techniques, the identification of the complete array of
processes regulated by sphingolipid signals is likely to be possible, as is the
quantification of the physiological contribution of each.
PMID- 9759482
TI - Transporters of nucleotide sugars, ATP, and nucleotide sulfate in the endoplasmic
reticulum and Golgi apparatus.
AB - The lumens of the endoplasmic reticulum and Golgi apparatus are the subcellular
sites where glycosylation, sulfation, and phosphorylation of secretory and
membrane-bound proteins, proteoglycans, and lipids occur. Nucleotide sugars,
nucleotide sulfate, and ATP are substrates for these reactions. ATP is also used
as an energy source in the lumen of the endoplasmic reticulum during protein
folding and degradation. The above nucleotide derivatives and ATP must first be
translocated across the membrane of the endoplasmic reticulum and/or Golgi
apparatus before they can serve as substrates in the above lumenal reactions.
Translocation of the above solutes is mediated for highly specific transporters,
which are antiporters with the corresponding nucleoside monophosphates as shown
by biochemical and genetic approaches. Mutants in mammals, yeast, and protozoa
showed that a defect in a specific translocator activity results in selective
impairments of the above posttranslational modifications, including loss of
virulence of pathogenic protozoa. Several of these transporters have been
purified and cloned. Experiments with yeast and mammalian cells demonstrate that
these transporters play a regulatory role in the above reactions. Future studies
will address the structure of the above proteins, how they are targeted to
different organelles, their potential as drug targets, their role during
development, and the possible occurrence of specific diseases.
PMID- 9759483
TI - Ribonucleotide reductases.
AB - Ribonucleotide reductases provide the building blocks for DNA replication in all
living cells. Three different classes of enzymes use protein free radicals to
activate the substrate. Aerobic class I enzymes generate a tyrosyl radical with
an iron-oxygen center and dioxygen, class II enzymes employ adenosylcobalamin,
and the anaerobic class III enzymes generate a glycyl radical from S
adenosylmethionine and an iron-sulfur cluster. The X-ray structure of the class I
Escherichia coli enzyme, including forms that bind substrate and allosteric
effectors, confirms previous models of catalytic and allosteric mechanisms. This
structure suggests considerable mobility of the protein during catalysis and,
together with experiments involving site-directed mutants, suggests a mechanism
for radical transfer from one subunit to the other. Despite large differences
between the classes, common catalytic and allosteric mechanisms, as well as
retention of critical residues in the protein sequence, suggest a similar
tertiary structure and a common origin during evolution. One puzzling aspect is
that some organisms contain the genes for several different reductases.
PMID- 9759484
TI - Modified oligonucleotides: synthesis and strategy for users.
AB - Synthetic oligonucleotide analogs have greatly aided our understanding of several
biochemical processes. Efficient solid-phase and enzyme-assisted synthetic
methods and the availability of modified base analogs have added to the utility
of such oligonucleotides. In this review, we discuss the applications of
synthetic oligonucleotides that contain backbone, base, and sugar modifications
to investigate the mechanism and stereochemical aspects of biochemical reactions.
We also discuss interference mapping of nucleic acid-protein interactions;
spectroscopic analysis of biochemical reactions and nucleic acid structures; and
nucleic acid cross-linking studies. The automation of oligonucleotide synthesis,
the development of versatile phosphoramidite reagents, and efficient scale-up
have expanded the application of modified oligonucleotides to diverse areas of
fundamental and applied biological research. Numerous reports have covered
oligonucleotides for which modifications have been made of the phosphodiester
backbone, of the purine and pyrimidine heterocyclic bases, and of the sugar
moiety; these modifications serve as structural and mechanistic probes. In this
chapter, we review the range, scope, and practical utility of such chemically
modified oligonucleotides. Because of space limitations, we discuss only those
oligonucleotides that contain phosphate and phosphate analogs as internucleotidic
linkages.
PMID- 9759485
TI - The molecular control of circadian behavioral rhythms and their entrainment in
Drosophila.
AB - Molecular and genetic characterizations of circadian rhythms in Drosophila
indicate that function of an intracellular pacemaker requires the activities of
proteins encoded by three genes: period (per), timeless (tim), and doubletime
(dbt). RNA from two of these genes, per and tim, is expressed with a circadian
rhythm. Heterodimerization of PER and TIM proteins allows nuclear localization
and suppression of further RNA synthesis by a PER/TIM complex. These protein
interactions promote cyclical gene expression because heterodimers are observed
only at high concentrations of per and tim RNA, separating intervals of RNA
accumulation from times of PER/TIM complex activity. Light resets these molecular
cycles by eliminating TIM. The product of dbt also regulates accumulation of per
and tim RNA, and it may influence action of the PER/TIM complex. The recent
discovery of PER homologues in mice and humans suggests that a related mechanism
controls mammalian circadian behavioral rhythms.
PMID- 9759486
TI - Ribonuclease P: unity and diversity in a tRNA processing ribozyme.
AB - Ribonuclease P (RNase P) is the endoribonuclease that generates the mature 5'
ends of tRNA by removal of the 5'-leader elements of precursor-tRNAs. This enzyme
has been characterized from representatives of all three domains of life
(Archaea, Bacteria, and Eucarya) (1) as well as from mitochondria and
chloroplasts. The cellular and mitochondrial RNase Ps are ribonucleoproteins,
whereas the most extensively studied chloroplast RNase P (from spinach) is
composed solely of protein. Remarkably, the RNA subunit of bacterial RNase P is
catalytically active in vitro in the absence of the protein subunit (2). Although
RNA-only activity has not been demonstrated for the archael, eucaryal, or
mitochondrial RNAs, comparative sequence analysis has established that these RNAs
are homologous (of common ancestry) to bacterial RNA. RNase P holoenzymes vary
greatly in organizational complexity across the phylogenetic domains, primarily
because of differences in the RNase P protein subunits: Mitochondrial, archaeal,
and eucaryal holoenzymes contain larger, and perhaps more numerous, protein
subunits than do the bacterial holoenzymes. However, that the nonbacterial RNase
P RNAs retain significant structural similarity to their catalytically active
bacterial counterparts indicates that the RNA remains the catalytic center of the
enzyme.
PMID- 9759487
TI - Base flipping.
AB - Base flipping is the phenomenon whereby a base in normal B-DNA is swung
completely out of the helix into an extrahelical position. It was discovered in
1994 when the first co-crystal structure was reported for a cytosine-5 DNA
methyltransferase binding to DNA. Since then it has been shown to occur in many
systems where enzymes need access to a DNA base to perform chemistry on it. Many
DNA glycosylases that remove abnormal bases from DNA use this mechanism. This
review describes systems known to use base flipping as well as many systems where
it is likely to occur but has not yet been rigorously demonstrated. The mechanism
and evolution of base flipping are also discussed.
PMID- 9759488
TI - The caveolae membrane system.
AB - The cell biology of caveolae is a rapidly growing area of biomedical research.
Caveolae are known primarily for their ability to transport molecules across
endothelial cells, but modern cellular techniques have dramatically extended our
view of caveolae. They form a unique endocytic and exocytic compartment at the
surface of most cells and are capable of importing molecules and delivering them
to specific locations within the cell, exporting molecules to extracellular
space, and compartmentalizing a variety of signaling activities. They are not
simply an endocytic device with a peculiar membrane shape but constitute an
entire membrane system with multiple functions essential for the cell. Specific
diseases attack this system: Pathogens have been identified that use it as a
means of gaining entrance to the cell. Trying to understand the full range of
functions of caveolae challenges our basic instincts about the cell.
PMID- 9759489
TI - How cells respond to interferons.
AB - Interferons play key roles in mediating antiviral and antigrowth responses and in
modulating immune response. The main signaling pathways are rapid and direct.
They involve tyrosine phosphorylation and activation of signal transducers and
activators of transcription factors by Janus tyrosine kinases at the cell
membrane, followed by release of signal transducers and activators of
transcription and their migration to the nucleus, where they induce the
expression of the many gene products that determine the responses. Ancillary
pathways are also activated by the interferons, but their effects on cell
physiology are less clear. The Janus kinases and signal transducers and
activators of transcription, and many of the interferon-induced proteins, play
important alternative roles in cells, raising interesting questions as to how the
responses to the interferons intersect with more general aspects of cellular
physiology and how the specificity of cytokine responses is maintained.
PMID- 9759490
TI - Nucleocytoplasmic transport: the soluble phase.
AB - Active transport between the nucleus and cytoplasm involves primarily three
classes of macromolecules: substrates, adaptors, and receptors. Some transport
substrates bind directly to an import or an export receptor while others require
one or more adaptors to mediate formation of a receptor-substrate complex. Once
assembled, these transport complexes are transferred in one direction across the
nuclear envelope through aqueous channels that are part of the nuclear pore
complexes (NPCs). Dissociation of the transport complex must then take place, and
both adaptors and receptors must be recycled through the NPC to allow another
round of transport to occur. Directionality of either import or export therefore
depends on association between a substrate and its receptor on one side of the
nuclear envelope and dissociation on the other. The Ran GTPase is critical in
generating this asymmetry. Regulation of nucleocytoplasmic transport generally
involves specific inhibition of the formation of a transport complex; however,
more global forms of regulation also occur.
PMID- 9759491
TI - Role of small G proteins in yeast cell polarization and wall biosynthesis.
AB - In the vegetative (mitotic) cycle and during sexual conjugation, yeast cells
display polarized growth, giving rise to a bud or to a mating projection,
respectively. In both cases one can distinguish three steps in these processes:
choice of a growth site, organization of the growth site, and actual growth and
morphogenesis. In all three steps, small GTP-binding proteins (G proteins) and
their regulators play essential signaling functions. For the choice of a bud
site, Bud1, a small G protein, Bud2, a negative regulator of Bud1, and Bud5, an
activator, are all required. If any of them is defective, the cell loses its
ability to select a proper bud position and buds randomly. In the organization of
the bud site or of the site in which a mating projection appears, Cdc42, its
activator Cdc24, and its negative regulators play a fundamental role. In the
absence of Cdc42 or Cdc24, the actin cytoskeleton does not become organized and
budding does not take place. Finally, another small G protein, Rho1, is required
for activity of beta (1-->3)glucan synthase, the enzyme that catalyzes the
synthesis of the major structural component of the yeast cell wall. In all of the
above processes, G proteins can work as molecular switches because of their
ability to shift between an active GTP-bound state and an inactive GDP-bound
state.
PMID- 9759492
TI - RNA localization in development.
AB - Cytoplasmic RNA localization is an evolutionarily ancient mechanism for producing
cellular asymmetries. This review considers RNA localization in the context of
animal development. Both mRNAs and non-protein-coding RNAs are localized in
Drosophila, Xenopus, ascidian, zebrafish, and echinoderm oocytes and embryos, as
well as in a variety of developing and differentiated polarized cells from yeast
to mammals. Mechanisms used to transport and anchor RNAs in the cytoplasm include
vectorial transport out of the nucleus, directed cytoplasmic transport in
association with the cytoskeleton, and local entrapment at particular cytoplasmic
sites. The majority of localized RNAs are targeted to particular cytoplasmic
regions by cis-acting RNA elements; in mRNAs these are almost always in the 3'
untranslated region (UTR). A variety of trans-acting factors--many of them RNA
binding proteins--function in localization. Developmental functions of RNA
localization have been defined in Xenopus, Drosophila, and Saccharomyces
cerevisiae. In Drosophila, localized RNAs program the antero-posterior and dorso
ventral axes of the oocyte and embryo. In Xenopus, localized RNAs may function in
mesoderm induction as well as in dorso-ventral axis specification. Localized RNAs
also program asymmetric cell fates during Drosophila neurogenesis and yeast
budding.
PMID- 9759493
TI - Biochemistry and genetics of von Willebrand factor.
AB - Von Willebrand factor (VWF) is a blood glycoprotein that is required for normal
hemostasis, and deficiency of VWF, or von Willebrand disease (VWD), is the most
common inherited bleeding disorder. VWF mediates the adhesion of platelets to
sites of vascular damage by binding to specific platelet membrane glycoproteins
and to constituents of exposed connective tissue. These activities appear to be
regulated by allosteric mechanisms and possibly by hydrodynamic shear forces. VWF
also is a carrier protein for blood clotting factor VIII, and this interaction is
required for normal factor VIII survival in the circulation. VWF is assembled
from identical approximately 250 kDa subunits into disulfide-linked multimers
that may be > 20,000 kDa. Mutations in VWD can disrupt this complex biosynthetic
process at several steps to impair the assembly, intracellular targeting, or
secretion of VWF multimers. Other VWD mutations impair the survival of VWF in
plasma or the function of specific ligand binding sites. This growing body of
information about VWF synthesis, structure, and function has allowed the
reclassification of VWD based upon distinct pathophysiologic mechanisms that
appear to correlate with clinical symptoms and the response to therapy.
PMID- 9759494
TI - The ubiquitin system.
AB - The selective degradation of many short-lived proteins in eukaryotic cells is
carried out by the ubiquitin system. In this pathway, proteins are targeted for
degradation by covalent ligation to ubiquitin, a highly conserved small protein.
Ubiquitin-mediated degradation of regulatory proteins plays important roles in
the control of numerous processes, including cell-cycle progression, signal
transduction, transcriptional regulation, receptor down-regulation, and
endocytosis. The ubiquitin system has been implicated in the immune response,
development, and programmed cell death. Abnormalities in ubiquitin-mediated
processes have been shown to cause pathological conditions, including malignant
transformation. In this review we discuss recent information on functions and
mechanisms of the ubiquitin system. Since the selectivity of protein degradation
is determined mainly at the stage of ligation to ubiquitin, special attention is
focused on what we know, and would like to know, about the mode of action of
ubiquitin-protein ligation systems and about signals in proteins recognized by
these systems.
PMID- 9759495
TI - Phosphoinositide kinases.
AB - Phosphatidylinositol, a component of eukaryotic cell membranes, is unique among
phospholipids in that its head group can be phosphorylated at multiple free
hydroxyls. Several phosphorylated derivatives of phosphatidylinositol,
collectively termed phosphoinositides, have been identified in eukaryotic cells
from yeast to mammals. Phosphoinositides are involved in the regulation of
diverse cellular processes, including proliferation, survival, cytoskeletal
organization, vesicle trafficking, glucose transport, and platelet function. The
enzymes that phosphorylate phosphatidylinositol and its derivatives are termed
phosphoinositide kinases. Recent advances have challenged previous hypotheses
about the substrate selectivity of different phosphoinositide kinase families.
Here we re-examine the pathways of phosphoinositide synthesis and the enzymes
involved.
PMID- 9759496
TI - The green fluorescent protein.
AB - In just three years, the green fluorescent protein (GFP) from the jellyfish
Aequorea victoria has vaulted from obscurity to become one of the most widely
studied and exploited proteins in biochemistry and cell biology. Its amazing
ability to generate a highly visible, efficiently emitting internal fluorophore
is both intrinsically fascinating and tremendously valuable. High-resolution
crystal structures of GFP offer unprecedented opportunities to understand and
manipulate the relation between protein structure and spectroscopic function. GFP
has become well established as a marker of gene expression and protein targeting
in intact cells and organisms. Mutagenesis and engineering of GFP into chimeric
proteins are opening new vistas in physiological indicators, biosensors, and
photochemical memories.
PMID- 9759497
TI - Alteration of nucleosome structure as a mechanism of transcriptional regulation.
AB - The nucleosome, which is the primary building block of chromatin, is not a static
structure: It can adopt alternative conformations. Changes in solution conditions
or changes in histone acetylation state cause nucleosomes and nucleosomal arrays
to behave with altered biophysical properties. Distinct subpopulations of
nucleosomes isolated from cells have chromatographic properties and nuclease
sensitivity different from those of bulk nucleosomes. Recently, proteins that
were initially identified as necessary for transcriptional regulation have been
shown to alter nucleosomal structure. These proteins are found in three types of
multiprotein complexes that can acetylate nucleosomes, deacetylate nucleosomes,
or alter nucleosome structure in an ATP-dependent manner. The direct modification
of nucleosome structure by these complexes is likely to play a central role in
appropriate regulation of eukaryotic genes.
PMID- 9759498
TI - Structure and function in GroEL-mediated protein folding.
AB - Recent structural and biochemical investigations have come together to allow a
better understanding of the mechanism of chaperonin (GroEL, Hsp60)-mediated
protein folding, the final step in the accurate expression of genetic
information. Major, asymmetric conformational changes in the GroEL double toroid
accompany binding of ATP and the cochaperonin GroES. When a nonnative
polypeptide, bound to one of the GroEL rings, is encapsulated by GroES to form a
cis ternary complex, these changes drive the polypeptide into the sequestered
cavity and initiate its folding. ATP hydrolysis in the cis ring primes release of
the products, and ATP binding in the trans ring then disrupts the cis complex.
This process allows the polypeptide to achieve its final native state, if folding
was completed, or to recycle to another chaperonin molecule, if the folding
process did not result in a form committed to the native state.
PMID- 9759499
TI - Matrix proteoglycans: from molecular design to cellular function.
AB - The proteoglycan superfamily now contains more than 30 full-time molecules that
fulfill a variety of biological functions. Proteoglycans act as tissue
organizers, influence cell growth and the maturation of specialized tissues, play
a role as biological filters and modulate growth-factor activities, regulate
collagen fibrillogenesis and skin tensile strength, affect tumor cell growth and
invasion, and influence corneal transparency and neurite outgrowth. Additional
roles, derived from studies of mutant animals, indicate that certain
proteoglycans are essential to life whereas others might be redundant. The review
focuses on the most recent genetic and molecular biological studies of the matrix
proteoglycans, broadly defined as proteoglycans secreted into the pericellular
matrix. Special emphasis is placed on the molecular organization of the protein
core, the utilization of protein modules, the gene structure and transcriptional
control, and the functional roles of the various proteoglycans. When possible,
proteoglycans have been grouped into distinct gene families and subfamilies
offering a simplified nomenclature based on their protein core design. The
structure-function relationship of some paradigmatic proteoglycans is discussed
in depth and novel aspects of their biology are examined.
PMID- 9759500
TI - G protein-coupled receptor kinases.
AB - G protein-coupled receptor kinases (GRKs) constitute a family of six mammalian
serine/threonine protein kinases that phosphorylate agonist-bound, or activated,
G protein-coupled receptors (GPCRs) as their primary substrates. GRK-mediated
receptor phosphorylation rapidly initiates profound impairment of receptor
signaling, or desensitization. This review focuses on the regulation of GRK
activity by a variety of allosteric and other factors: agonist-stimulated GPCRs,
beta gamma subunits of heterotrimeric GTP-binding proteins, phospholipid
cofactors, the calcium-binding proteins calmodulin and recoverin,
posttranslational isoprenylation and palmitoylation, autophosphorylation, and
protein kinase C-mediated GRK phosphorylation. Studies employing recombinant,
purified proteins, cell culture, and transgenic animal models attest to the
general importance of GRKs in regulating a vast array of GPCRs both in vitro and
in vivo.
PMID- 9759501
TI - Enzymatic transition states and transition state analog design.
AB - All chemical transformations pass through an unstable structure called the
transition state, which is poised between the chemical structures of the
substrates and products. The transition states for chemical reactions are
proposed to have lifetimes near 10(-13) sec, the time for a single bond
vibration. No physical or spectroscopic method is available to directly observe
the structure of the transition state for enzymatic reactions. Yet transition
state structure is central to understanding catalysis, because enzymes function
by lowering activation energy. An accepted view of enzymatic catalysis is tight
binding to the unstable transition state structure. Transition state mimics bind
tightly to enzymes by capturing a fraction of the binding energy for the
transition state species. The identification of numerous transition state
inhibitors supports the transition state stabilization hypothesis for enzymatic
catalysis. Advances in methods for measuring and interpreting kinetic isotope
effects and advances in computational chemistry have provided an experimental
route to understand transition state structure. Systematic analysis of intrinsic
kinetic isotope effects provides geometric and electronic structure for enzyme
bound transition states. This information has been used to compare transition
states for chemical and enzymatic reactions; determine whether enzymatic
activators alter transition state structure; design transition state inhibitors;
and provide the basis for predicting the affinity of enzymatic inhibitors.
Enzymatic transition states provide an understanding of catalysis and permit the
design of transition state inhibitors. This article reviews transition state
theory for enzymatic reactions. Selected examples of enzymatic transition states
are compared to the respective transition state inhibitors.
PMID- 9759502
TI - The DNA replication fork in eukaryotic cells.
AB - Replication of the two template strands at eukaryotic cell DNA replication forks
is a highly coordinated process that ensures accurate and efficient genome
duplication. Biochemical studies, principally of plasmid DNAs containing the
Simian Virus 40 origin of DNA replication, and yeast genetic studies have
uncovered the fundamental mechanisms of replication fork progression. At least
two different DNA polymerases, a single-stranded DNA-binding protein, a clamp
loading complex, and a polymerase clamp combine to replicate DNA. Okazaki
fragment synthesis involves a DNA polymerase-switching mechanism, and maturation
occurs by the recruitment of specific nucleases, a helicase, and a ligase. The
process of DNA replication is also coupled to cell-cycle progression and to DNA
repair to maintain genome integrity.
PMID- 9759503
TI - TGF-beta signal transduction.
AB - The transforming growth factor beta (TGF-beta) family of growth factors control
the development and homeostasis of most tissues in metazoan organisms. Work over
the past few years has led to the elucidation of a TGF-beta signal transduction
network. This network involves receptor serine/threonine kinases at the cell
surface and their substrates, the SMAD proteins, which move into the nucleus,
where they activate target gene transcription in association with DNA-binding
partners. Distinct repertoires of receptors, SMAD proteins, and DNA-binding
partners seemingly underlie, in a cell-specific manner, the multifunctional
nature of TGF-beta and related factors. Mutations in these pathways are the cause
of various forms of human cancer and developmental disorders.
PMID- 9759504
TI - Pathologic conformations of prion proteins.
AB - While many aspects of prion disease biology are unorthodox, perhaps the most
fundamental paradox is posed by the coexistence of inherited, sporadic, and
infectious forms of these diseases. Sensible molecular mechanisms for prion
propagation must explain all three forms of prion diseases in a manner that is
compatible with the formidable array of experimental data derived from
histopathological, biochemical, biophysical, human genetic, and transgenetic
studies. In this review, we explore prion disease pathogenesis initially from the
perspective of an autosomal dominant inherited disease. Subsequently, we examine
how an intrinsically inherited disease could present in sporadic and infectious
forms. Finally, we explore the phenomenologic constraints on models of prion
replication with a specific emphasis on biophysical studies of prion protein
structures.
PMID- 9759505
TI - The AMP-activated/SNF1 protein kinase subfamily: metabolic sensors of the
eukaryotic cell?
AB - Mammalian AMP-activated protein kinase and yeast SNF1 protein kinase are the
central components of kinase cascades that are highly conserved between animals,
fungi, and plants. The AMP-activated protein kinase cascade acts as a metabolic
sensor or "fuel gauge" that monitors cellular AMP and ATP levels because it is
activated by increases in the AMP:ATP ratio. Once activated, the enzyme switches
off ATP-consuming anabolic pathways and switches on ATP-producing catabolic
pathways, such as fatty acid oxidation. The SNF1 complex in yeast is activated in
response to the stress of glucose deprivation. In this case the intracellular
signal or signals have not been identified; however, SNF1 activation is
associated with depletion of ATP and elevation of AMP. The SNF1 complex acts
primarily by inducing expression of genes required for catabolic pathways that
generate glucose, probably by triggering phosphorylation of transcription
factors. SNF1-related protein kinases in higher plants are likely to be involved
in the response of plant cells to environmental and/or nutritional stress.
PMID- 9759506
TI - In favor of pediatric neutering.
PMID- 9759507
TI - An ethicist's commentary on the case of the pregnant dog brought in for a spay
and found to be pregnant.
PMID- 9759508
TI - Veterinary medicine in Canada: opportunity for renewal.
PMID- 9759510
TI - Turbulence in veterinary education.
PMID- 9759509
TI - Vaccination of dogs and cats: general principles and duration of immunity.
PMID- 9759511
TI - Atypical sporadic lymphosarcoma in a 7-month-old Holstein heifer.
AB - A 7-month-old calf with a firm, diffuse infiltration of the left hind limb with
sciatic nerve motor deficit was presented. The cytology indicated a malignant,
round cell tumor and at necropsy, tissues were positive to a Kappa-lambda
immunohistochemistry test. The final diagnosis was sporadic bovine leukosis,
juvenile form.
PMID- 9759512
TI - First report of Fasciola hepatica in cattle in Alberta.
PMID- 9759513
TI - Focal symmetrical encephalomalacia in a 6-month-old Dorset sheep.
AB - Neurological examination of a sheep that had acute onset of recumbency and mental
depression indicated a diffuse symmetrical thalamocortical lesion. Cerebrospinal
fluid analysis suggested a degenerative central nervous system disease. Thiamin
administration resulted in partial and temporary improvement. Brain histological
lesions were typical of focal symmetrical encephalomalacia.
PMID- 9759514
TI - Partial carpal arthrodesis in a calf with chronic infectious arthritis of the
carpus and osteomyelitis of the carpal and metacarpal bones.
AB - A calf was treated for chronic infectious arthritis and osteomyelitis of the
carpus and metacarpus by carpal bone excision, debridement, and cancellous bone
graft placement in the metacarpal medullary cavity. Following 6 weeks of limb
immobilization, carpal-metacarpal arthrodesis was achieved. The heifer is pain
free, and has produced 3 calves.
PMID- 9759515
TI - Canine coccidiosis.
PMID- 9759516
TI - Equine osteology: a self-assessment.
PMID- 9759517
TI - Abnormal interactions of embryonic mouse trisomy 16 heart fibroblasts with
extracellular matrix components in vitro.
AB - Trisomy 16 mice have cardiovascular abnormalities thought to arise from altered
development and maturation of the cardiac cushions. Cell-cell and cell
extracellular matrix (ECM) interactions play critical roles in heart
morphogenesis. To begin to examine the potential involvement of cell-ECM
interactions in abnormal trisomy 16 heart development, fibroblasts were isolated
from normal and trisomy 16 embryonic mouse hearts. Behavior of these cells was
compared in bioassays involving cell-ECM interactions including cell attachment
and collagen gel contraction. Significant differences in cell-ECM interactions
were found between fibroblasts isolated from normal and trisomy 16 embryonic
hearts. Trisomy 16 cells attached poorly to collagen and laminin compared to
normal fibroblasts. Trisomy 16 heart fibroblasts also contracted collagen gels
less effectively than normal heart fibroblasts. Cell-ECM interactions are largely
mediated by ECM receptors of the integrin family. Expression of beta 1 integrins
was examined at the mRNA and protein levels in normal and trisomy 16 fibroblasts.
Analyses of integrin expression indicated the pattern of integrins produced by
normal and trisomy 16 fibroblasts to be similar. These results indicate that
fibroblasts isolated from embryonic trisomy 16 mouse hearts interact with several
ECM components including collagen and laminin less efficiently than fibroblasts
from normal mouse embryos. As cell-ECM interactions play significant roles in
cardiac cushion development, abnormal interactions may contribute to defective
atrioventricular septal morphogenesis in the trisomy 16 mouse.
PMID- 9759518
TI - The leukointegrin alpha d/beta 2 (alpha d/CD18): specific changes in surface
expression in patients on hemodialysis.
AB - Alpha d/CD18 is a newly discovered leukocyte adhesion molecule with sequence
homology to CD11a, b and c of the beta 2 integrin family. Little is known about
alpha d expression in vivo, particularly how it compares with the other beta 2
integrins. Previous studies have demonstrated that beta 2 integrin expression,
particularly CD11b, is upregulated in vivo during hemodialysis (HD) with
complement activating membranes. These changes may contribute to the immunologic
abnormalities seen in HD patients. Given the well described changes of beta 2
integrins in these patients, we hypothesized that alpha d expression could also
be altered by HD. Using flow cytometry with two specific antibodies to alpha d,
alpha d expression in healthy adults (n = 16) was compared on macrophages (MO) >
polymorphonuclear cells (PMNs) > lymphocytes (LY). Phorbol ester treatment of
leukocytes in vitro significantly increased expression on MO and PMN, but not LY.
Chronic HD patients at baseline (n = 15) had elevated (P < 0.05) alpha d mean
channel fluorescence (MCF) on MOs, PMNs and LYs compared to normals. PMN alpha d
MCF increased at 15 min into HD, but then returned to baseline levels at 180 min.
Alpha d MCF for LYs decreased at 180 min, while MOs levels were unchanged. Alpha
d expression is increased in chronic renal failure and further regulated by
hemodialysis, but with unique characteristics compared to the other beta 2
integrins. Alpha d may be important in abnormal cell-cell contacts in renal
failure.
PMID- 9759520
TI - Aggregation independent of N-cadherin and neural cell adhesion molecule on quail
myoblasts transformed with temperature-sensitive Rous sarcoma virus.
AB - Quail myoblasts transformed with the temperature-sensitive mutant of Rous sarcoma
virus (QM-RSV cells) differentiate temperature-sensitively. At 41 degrees C, the
cells begin to fuse after about 15-18 h and form multinucleated myotubes,
whereas, at 35.5 degrees C, the cells proliferate. Tyrosine-phosphorylation
relates to this temperature-sensitive differentiation. In the course of the
investigation of QM-RSV cells, when QM-RSV cells were dissociated with EDTA and
shaken in DMEM, the aggregation activity was detected. This activity was
expressed on the cells cultured at 41 degrees C, but not at 35.5 degrees C. For
detailed characterization of the aggregation, cells from which cadherin and/or
neural cell adhesion molecule (NCAM) were removed by trypsin treatment were used.
It was then observed that temperature-sensitive and calcium-dependent aggregation
activity was expressed on the cells treated with trypsin and EDTA (TE-cells),
although the TE-cells did not retain either aggregation molecule. The aggregation
activity began to be expressed at 2-4 h after temperature shift and increased
with the differentiation. The expression of the activity related to the tyrosine
phosphorylation of some protein. The aggregation of TE-cells was completely
inhibited by D(+)-mannose, D(+)-glucose, and N-acetyl-D-glucosamine, but D(+)
galactose did not affect the aggregation. Thus, the present results suggest that
the aggregation of mannose specific C-type animal lectin recognized on TE-cells
relates to the early stage of the differentiation of QM-RSV cells.
PMID- 9759519
TI - Engagement of variant CD44 confers resistance to anti-integrin antibody-mediated
apoptosis in a colon carcinoma cell line.
AB - The LIM 1863 colon carcinoma cell line grows as structured organoids around a
central lumen, and we have previously demonstrated that the three-dimensional
arrangement protects the individual cells from apoptosis induced by an anti-alpha
v integrin antibody, 23C6 (Bates et al., 1994). Here we show that the
intercellular forces which drive spheroid formation can be overcome by exposure
of the cells to a collagen substrate, or more specifically through ligation of
the CD44 receptor by a monoclonal antibody. Binding to immobilized anti-CD44
antibody induced a monolayer morphology which is accompanied by fibronectin
production and secretion, and expression of the integrin alpha v beta 6.
Significantly, the cells of the monolayer acquired resistance to 23C6 antibody
mediated apoptosis over time and this property was sustained even after removal
from the monolayer. We provide data to show that this resistance is not dependent
on monolayer morphology, constant engagement of the CD44 receptor, loss of the
23C6 antigen, or elevation of Bcl-2 or Bcl-XL protein. The CD44 expressed by LIM
1863 is shown to be the metastatic variant of the molecule therefore these
results provide a possible explanation for the selective advantages conferred by
expression of this variant for metastasizing colon cancer cells. Overall, the
findings of this study support a model for the development of malignancy through
the production of specific survival and growth signals as a direct consequence of
a signaling event induced by stimulation of an epithelial variant of CD44.
PMID- 9759521
TI - Cadherin/catenin complexes in murine epidermal keratinocytes: E-cadherin
complexes containing either beta-catenin or plakoglobin contribute to stable cell
cell contacts.
AB - The cadherin/catenin complexes expressed by a murine epidermal keratinocyte cell
line PDV, expressing E- and P-cadherin, have been analysed using a combination of
biochemical and confocal microscopy analysis. Two types of E-cadherin complexes,
containing beta-catenin or plakoglobin and alpha-catenin, were detected in PDV
cells as in other cell types, while P-cadherin was mainly detected in complexes
containing beta-catenin and alpha-catenin in PDV and other murine epidermal
keratinocytes. Biotin-labelling studies have shown that both types of E-cadherin
complexes are present at the surface of confluent cells. Furthermore, confocal
microscopy analysis indicated that E-cadherin/plakoglobin complexes are located
in stable cell-cell contacts at the middle lateral membranes and associated with
alpha-catenin and the actin cytoskeleton, with a similar distribution to that to
the E-cadherin/beta-catenin complexes. In addition, E-cadherin/plakoglobin
complexes not associated with alpha-catenin or the actin cytoskeleton were
detected in lower planes of the lateral contacting membranes as well as E
cadherin non-associated with catenins in the more basal planes. These studies
support that in murine epidermal keratinocytes both beta-catenin- and plakoglobin
containing E-cadherin complexes contribute to the maintenance of stable cell-cell
contacts and suggest a differential role of the plakoglobin containing complexes
in different epithelial cell types.
PMID- 9759522
TI - Expression of cell adhesion molecules and cytokines in murine antigen-induced
arthritis.
AB - Adhesion molecules and cytokines are important in chronic inflammatory conditions
such as rheumatoid arthritis (RA) by virtue of their role in cell activation and
emigration. Using immunohistochemical techniques we studied the expression of
adhesion molecules and cytokines in cryopreserved sections of murine knee joint
in the course of antigen-induced arthritis, an animal model of human RA. Various
adhesion molecules and cytokines are expressed in the arthritic joint tissue. LFA
1, Mac-1, CD44, ICAM-1 and P-selectin were strongly expressed in the acute phase
and to a lesser degree in the chronic phase of arthritis. VLA-4 and VCAM-1
appeared to be moderately expressed on day 1, L-selectin between days 1 and 3.
LFA-1, Mac-1, CD44, alpha 4-integrin, ICAM-1 and the selectins were found
expressed on cells of the synovial infiltrate, LFA-1, Mac-1 and ICAM-1 on the
synovial lining layer, and VCAM-1 and P-selectin on endothelial cells. Expression
of E-selectin could be demonstrated throughout the experiment at a low level in
cells of the acute cell infiltrate. Cytokines, especially IL-2, IL-4, IL-6, TNF,
and IFN-gamma, were heavily expressed during the acute phase of arthritis in
cellular infiltrate. Taken together these data demonstrate that cytokines and
their activation of adhesion molecules contribute to cell infiltration and
activation during the initial phase of arthritis and to the induction and
progression of tissue destruction in arthritic joints. These molecules might be
potential targets for novel therapeutic strategies in inflammatory and arthritic
disorders.
PMID- 9759523
TI - Ad libitum mixing in a taste memory task: methodological issues.
AB - Ad libitum mixing, an application of the method of adjustment in food research,
was investigated and evaluated for the purpose of taste memory research. The
difference between ascending and descending runs in mixing was studied using a
wide range of prefill concentrations lower and higher than standard. The effect
of training was studied by comparing subjects with two or 10 replications in the
first session where a standard was present as a reference. Results showing higher
reproduced concentrations after a 25 h time interval than those produced
immediately are consistent with earlier results from within-subject designs.
Thus, the difference in recall performance did not depend on the design of the
study. No difference between ascending and descending runs in the mixing was
observed, thus the prefill concentrations did not affect the reproduction of a
given standard. There was no significant difference between produced
concentrations after two and 10 replications, although a non-significant trend
towards improved performance following 10 replications was observed after the 25
h time interval.
PMID- 9759524
TI - Pheromone deactivation catalyzed by receptor molecules: a quantitative kinetic
model.
AB - A quantitative model of pheromone-receptor interaction and pheromone
deactivation, the supposed rate-limiting processes underlying the receptor
potential kinetics, is worked out for the moth Antheraea polyphemus. In this
model, the pheromone interacts with the receptor molecule while bound to the
reduced form of the pheromone binding protein. The receptor molecules--besides
their receptor function--catalyze the observed shift of the pheromone-binding
protein from the reduced to the oxidized form (Ziegelberger, G., Eur. J.
Biochem., 232, 706-711, 1995), which deactivates the pheromone bound to pheromone
binding protein. With the following parameters, the model fits morphological,
radiometric, electrophysiological and biochemical data: a maximum estimate of 1.7
x 10(7) receptor molecules/cell (with 40,000 units/micron 2 of receptor cell
membrane), rate constants k1 = 0.2/(s.microM) for the association, k2 = 10/s for
the dissociation of the ternary complex of binding protein, pheromone and
receptor, and k3 = 10/s for the deactivation via the redox shift. With these
parameters, the duration of elementary receptor potentials elicited by single
pheromone molecules (approximately 50 ms) reflects the lifetime of the ternary
complex, tau = 1/(k2 + k3). The receptor occupancy produced by the model for
threshold stimuli fits the sensitivity of the receptor cell to single pheromone
molecules.
PMID- 9759525
TI - The addition of CO2 to traditional taste solutions alters taste quality.
AB - Previous studies of the effect of carbonation on taste perception have suggested
that it may be negligible, manifesting primarily in increases in the perceived
intensity of weak salt and sour stimuli. Assuming CO2 solutions in the mouth
stimulate only trigeminal nerve endings, this result is not altogether
surprising; however, there are neurophysiological data indicating that CO2
stimulates gustatory as well as trigeminal fibers. In that case, carbonation
might alter the quality profile of a stimulus without producing substantial
changes in overall taste intensity--much as occurs when qualitatively different
taste stimuli are mixed. To address this possibility, subjects were asked to rate
the total taste intensity of moderate concentrations of stimuli representing each
of the basic tastes and their binary combinations, with an without added
carbonation. They then subdivided total taste intensity into the proportions of
sweetness, saltiness, sourness, bitterness and 'other taste qualities' they
perceived. The addition of carbonation produced only small increases in ratings
of total taste intensity. However, rather dramatic alterations in the quality
profiles of stimuli were observed, particularly for sweet and salty tastes. The
nature of the interaction is consistent with a direct effect of carbonation/CO2
on the gustatory system, although the possibility that at least some of the
observed effects reflect trigeminal-gustatory interactions cannot be ruled out.
PMID- 9759526
TI - PTC and PROP behave differently in tests of discrimination from their solvents.
AB - Better discrimination was possible between phenylthiocarbamide (PTC) solutions
and the pure solvent when the solvent was a tasteless low-concentration NaCl
solution to which the subject had adapted than when the solvent was purified
water. The reverse was true for 6-n-propylthiouracil (PROP). The differences in
discrimination for PROP and PTC in the different solvents were caused by
differences in the intensity and persistence of aftertastes, rather than a more
intense perception of the PTC and PROP tastes per se. This has consequences for
traditional approaches to measuring taste sensitivity, as well as indicating that
PTC and PROP are not necessarily equivalent indicators of 'taster' versus 'non
taster' status.
PMID- 9759527
TI - NaCl-preferring NZB/B1NJ mice and NaCl-avoiding CBA/J mice have similar amiloride
inhibition of chorda tympani responses to NaCl.
AB - Integrated chorda tympani nerve responses to NaCl were studied in two mouse
strains, an NaCl-preferring NZB/B1NJ and an NaCl-avoiding CBA/J. The NaCl
responses of both strains had similar magnitude and were suppressed by amiloride
to a similar extent. This suggests that peripheral gustatory responsiveness to
NaCl is not the only mechanism underlying mouse strain variation in NaCl
acceptance.
PMID- 9759528
TI - Influence of physical exercise on human preferences for various taste solutions.
AB - The effects of physical exercise on preference for various sapid solutions was
studied in 58 healthy university students. After 30 min of exercise using a
bicycle ergometer at 50% VO2max (maximal oxygen uptake) intensity, a rating scale
test on taste hedonic tone and the triangle test for taste absolute threshold
were done. The test solutions were sucrose, NaCl, citric acid, caffeine and
monosodium glutamate (MSG). Preference scale values for sucrose and citric acid
increased after exercise, whereas the values for NaCl, caffeine and MSG were not
changed. The absolute thresholds for all the sapid solutions did not differ for
pre- and post-exercise. These findings indicate that in humans preference for
sucrose and citric acid increase after physical exercise.
PMID- 9759529
TI - Attentional modulation of central odor processing.
AB - Two studies were conducted to investigate the influence of attention on the
components of the chemosensory event-related potential (CSERP). In the first
study the odors linalool and eugenol were delivered to six male subjects, in the
second study three male and two female subjects were presented with their own
body odor (axillary hair) and the body odor of a same sex donor. In both studies
the odors were presented in an oddball paradigm under ignore and attend
conditions via a constant-flow olfactometer. In the ignore condition attention
was diverted from the odors with a distractor task, while in the attend condition
the subjects were asked to respond to the infrequently occurring odor. In both
studies the allocation of attention led to a decrease in the latency of the early
components (N1, P2, N2) and to an increase in the amplitude of the late
positivities. The modulation of the early components suggests that attentional
gating in olfaction might already be effective at an early processing level.
PMID- 9759530
TI - Olfactory memory: the long and short of it.
AB - It has been proposed that memory for odors does not have a short-term (or
working) memory system. The distinction between short- and long-term memory in
other sensory modalities has been generally supported by three main lines of
evidence: capacity differences between the proposed systems, evidence of
differential coding, and differential memory losses in neuropsychological
patients. The present paper examines these issues in an effort to establish a
similar distinction for the memory of olfactory stimuli. Each of these lines of
evidence is examined in relation to the literature on olfactory memory. Based on
this examination, it seems that there is at least preliminary support from each
of these lines of evidence to advocate a distinction between a long- and short
term memory for olfactory stimuli. Emphasis is placed upon the qualitative
similarity of olfactory memory to other memory systems. This similarity is
further highlighted through an examination of the literature pertinent to serial
position effects in memory for olfactory stimuli.
PMID- 9759531
TI - Is there an inner nose?
AB - Although behavioral and neuropsychological data regarding the existence of images
for odors are inconclusive, reconsideration of earlier EEG work provides
reasonably clear evidence for an inner nose. However, further EEG studies and
neuroimaging data seem essential for conclusive demonstration of an inner nose.
PMID- 9759532
TI - Theoretical note: tests of synergy in sweetener mixtures.
AB - Some methods for examining the additivity of sweeteners, and their synergy in
mixtures depend upon setting component concentrations on the basis of sweetness
equivalence, usually to a sucrose reference. These methods may under- or over
predict the sweetness of a mixture, leading to spurious claims of synergy or
mixture suppression. This paper points out one problem with one such popular
method, in that the method can lead to a conclusion that a substance would
synergize with itself. To the extent that self-synergy is an illogical conclusion
for a mixture comparison, such a method should be avoided in tests of synergy.
The sweetness equivalence approach is contrasted with a simpler approach based on
concentrations that does not lead to conclusions of self-synergy.
PMID- 9759534
TI - Vomeronasal function.
AB - This contribution briefly explores some unanswered questions about vomeronasal
organ function, and introduces other contributions from the symposium
'Vomeronasal Function', presented at the XVII Meeting of the Association for
Chemoreception Sciences (1996). Key publications appearing since the symposium
are also listed.
PMID- 9759533
TI - Bilateral detection thresholds in dextrals and sinistrals reflect the more
sensitive side of the nose, which is not lateralized.
AB - Several fundamental questions remain enigmatic concerning human olfactory
sensitivity, including (i) whether detection threshold differences exist between
the two sides of the nose (and, if so, whether such differences are influenced by
handedness) and (ii) whether bilateral (i.e. binasal) stimulation leads to lower
thresholds than unilateral stimulation (and, if so, whether the degree of
facilitation is inversely related to general olfactory ability). In this study,
and well-validated single staircase procedure was used to establish bilateral and
unilateral detection thresholds for the cranial nerve I stimulant phenyl ethyl
alcohol in 130 right- and 33 left-handed subjects. No differences in sensitivity
between the left and right sides of the nose were observed in either group.
Bilateral thresholds were lower, on average, than unilateral thresholds when the
latter were categorized in terms of left and right nares. However, the bilateral
thresholds did not differ significantly from those of the side of the nose with
the lower threshold. Overall smell ability, as measured by the University of
Pennsylvania Smell Identification Test, did not interact with any of the test
measures. These data imply that (i) the left and right sides of the nose do not
systematically differ in detection threshold sensitivity for either dextrals or
sinistrals and (ii) if central integration of left:right olfactory threshold
sensitivity occurs, its effects do not exceed the function of the better side of
the nose.
PMID- 9759535
TI - Expression of candidate pheromone receptor genes in vomeronasal neurons.
AB - In mammals, olfactory sensory perception is mediated by two anatomically and
functionally distinct organs: the main olfactory epithelium (MOE) and the
vomeronasal organ (VON). Pheromones activate the VNO and elicit a characteristic
array of innate reproductive and social behaviors, along with dramatic
neuroendocrine responses. Recent approaches have provided new insights into the
molecular biology of sensory transduction in the VNO. Differential screening of
cDNA libraries constructed from single sensory neurons from the rat VNO has led
to the isolation of a family of genes which are likely to encode mammalian
pheromone receptors. The isolation of these receptors from the VNO might permit
the analysis of the molecular events which translate the bindings of pheromones
into innate stereotypic behaviors and help to elucidate the logic of pheromone
perception in mammals.
PMID- 9759536
TI - Heterogeneity in the accessory olfactory system.
AB - The mammalian accessory olfactory bulb (AOB) is chemoarchitecturally
heterogeneous in that it stains differentially with a number of markers; the
receptor cells that project to the AOB are similarly heterogeneous. What is the
significance of this heterogeneity? We have found that the AOB of the gray, short
tailed opossum, Monodelphis domestica, stains differentially with a number of
'markers': antibodies to olfactory marker protein (OMP) and the alpha subunit of
the G protein Gi2, the lectin of Vicia villosa and NADPH-diaphorase. These
markers stain the rostral AOB more strongly than the caudal AOB whereas, the G
protein subunit G(o) alpha is located predominantly in the posterior subdivision
of the AOB. This heterogeneity in the chemoarchitecture of the AOB may reflect a
fundamental organizational dichotomy within the vomeronasal system that
corresponds to a functional dichotomy. The vomeronasal sensory epithelium also
exhibits a chemoarchitectural heterogeneity: receptor cells in the basal third
are G(o) alpha-immunoreactive whereas the cells in the middle third are Gi2 alpha
immunoreactive. Tracing studies using WGA-HRP demonstrate that the neurons in the
middle third of the vomeronasal sensory epithelium project their axons to the
anterior AOB whereas those in the basal third appear to project to the posterior
AOB.
PMID- 9759537
TI - Electrophysiological and biochemical responses of mouse vomeronasal receptor
cells to urine-derived compounds: possible mechanism of action.
AB - Receptor cells of the vomeronasal organ (VNO) are thought to detect pheromone
like molecules important for reproductive physiology. Several compounds derived
from male mouse urine have been demonstrated to affect endocrine events in female
mice. In the present study, the ability of these compounds to affect VNO activity
was tested. In dissociated VNO cells held under voltage clamp conditions,
application of dehydro-exo-brevicomin (DHB) evoked an outward current at negative
holding potentials and an inward current at positive holding potentials. Under
current clamp, DHB reduced action potential firing. Since DHB application caused
a decrease in membrane conductance, this compound appeared to act by reducing
inward current through closing an ion channel. Biochemical experiments tested the
effects of DHB and 2-(sec-butyl)-4,5-dihydrothiazole (SBT) on cAMP levels in the
VNO. A mixture of DHB and SBT decreased cAMP levels in VNO sensory tissue and had
no effect on VNO non-sensory tissue. The results suggest that pheromones have an
inhibitory influence on action potential generation and on cAMP levels in
receptor cells of the VNO.
PMID- 9759538
TI - Vomeronasal/accessory olfactory system and pheromonal recognition.
AB - Pregnancy block in mice requires exposure of recently mated females to urinary
pheromones of a strange male, and when working with inbred strains this
invariably requires urine from an outbred line. The pheromones which induce
oestrus and early puberty in mice have been identified as the brevicomins and
dihydrothiazoles. Since the same vomeronasal, neural and neuroendocrine pathways
are also activated in pregnancy block, these compounds are likely candidates for
pregnancy blocking pheromones. However, these relatively simple chemicals lack
the capacity to code for differing mouse strains. Since large quantities of the
polymorphic major urinary proteins from the lipocalin family found in urine serve
as transporters for the dihydrothiazoles and brevicomins, and differ across
strains, then these proteins must participate in pheromone recognition in the
context of pregnancy block.
PMID- 9759539
TI - Construction of Escherichia coli-Streptomyces shuttle expression vectors for gene
expression in Streptomyces.
AB - pIJ4123 and pIJ6021 are high-copy-number vectors for gene expression in
Streptomyces. They contain a strong, thiostrepton-inducible promoter, PtipA. Two
E. coli-Streptomyces shuttle vectors, pHZ1271 and pHZ1272, were constructed by
inserting a replicon and bla gene from E. coli into pIJ4123 and pIJ6021,
respectively. Both vectors were structurally stable either in E. coli or in
Streptomyces lividans. To demonstrate the utility of pHZ1272, the hemoglobin gene
of Vitreoscillia (vhb) was cloned into pHZ1272 and expressed in Streptomyces
lividans. The expression product (VHb) was detected by Western blotting and
carbon monoxide binding activity analysis.
PMID- 9759540
TI - Inhibition effect of transgenic tobacco plants expressing snowdrop lectin on the
population development of Myzus persicae.
AB - The cDNAs of snowdrop lectin mature protein and its precursor protein, GNA12 and
GNA34, were inserted downstream of a 35S promoter with a double enhancer and a
"omega" fragment of TMV-RNA cDNA in the binary vector pBin438, or the phloem
specific CoYMV promoter in the vector pBcop1, respectively, resulting in the
construction of four plant expression vectors pBGna12, pBGna34, pBCGna12, and
pBCGna34. Leaf stripes of Nicotiana tabacum var. K326 were transformed with A.
tumefaciens LBA4404 harboring the above expression vectors, respectively. PCR and
Southern blot analysis showed that foreign GNA genes were inserted into the
genome of transformed tobacco plants. Western blot analysis indicated that GNA
could be expressed efficiently up to 0.08-0.15% of total soluble proteins in
transgenic tobacco plants with pBGna34 or pBCGna34, while in those with pBGna12
and pBCGna12 GNA were hardly detected by immunoassay. The results from insect
bioassay with a peach aphid (Myzus persicae) demonstrated that the transgenic
plants of pBGna34 and pBCGna34 were aphid-resistant as shown by a 45-60%
reduction in insect population density, with some individual transgenic lines
being reduced by over 90%. In addition, it was evident that the 35S promoter with
a double enhancer and CoYMV promoter had similar abilities to direct the GNA gene
to express in transgenic tobacco plants, but because the CoYMV promoter drives
the foreign gene in a phloem-specific expression manner, the transgenic plants of
pBCGna34 showed higher aphid resistance.
PMID- 9759541
TI - Homology modeling of tissue-type plasminogen activator K1 domain and studies on
the interactions between kringles and lysine.
AB - The 3-D structure of t-PA K1 domain was predicted by the method of homology
modeling. The putative lysine-binding pockets of t-PA K1, UK K, PLG K1 and K4
were determined by superimposing their 3-D structures to that of t-PA K2 domain,
of which the lysine-binding pockets had been revealed previously. After that the
key residues of lysine-binding pockets of kringles were identified. The
structural analyses showed that both the electrostatic potential and hydrophobic
complementarity were well matched between lysine and the binding pockets of t-PA
K2, PLG K1 and K4, but for t-PA K1 and UK K domains the complementarity did not
match well in one or both respects. It is proposed that this is the reason that t
PA K1 and UK K domains do not bear the ability to bind lysine. With the respect
of improving the affinity for fibrin, new types of mutants of t-PA K1 and UK K
domains were designed, and structural changes caused by mutation were predicted
by simulating the residue replacements. The mutant structural models demonstrated
that the molecular design was reasonable.
PMID- 9759542
TI - Molecular cloning of a chitinase gene from Bacillus circulans C-2.
AB - The 2-10 kb DNA fragments of the PstI partially digested total DNA of Bacillus
circulans C-2 were cloned into the PstI site of vector pUC19 and the resulting
hybrid DNA molecules were then transformed into Escherichia coli. One chitinase
gene-containing clone (named pCHT1) was selected from about 8000 recombinants on
chitin overlay plates. Analysis of pCHT1 cut with 12 restriction enzymes showed
that the inserted fragment in this clone was about 3.0 kb in size and contained
one site for each of the three restriction enzymes: KpnI, SacI, and SspI. Cells
harboring the recombinants plasmid (pCHT1-R) in which the insert was in an
inverted orientation also displayed chitinase activity, indicating that the
cloned fragment from B. circulans C-2 contained an intact chitinase gene and its
own promoter could be recognized by the Escherichia coli transcriptional system.
Southern hybridization analysis proved that the inserted fragment of pCHT1 was
really from the genome of B. circulans C-2, and there was only one copy existing
in the genome. This fragment could not hybridize with the total DNAs from the
other seven chitinase-producing bacteria.
PMID- 9759543
TI - Regulation of callus status and cell-suspending culture in naked seed oat (Avena
nuda).
AB - The original calli were obtained by inducing culture of mature embryos of naked
seed oat on N6 medium. The original calli were white-colored tumor forms, soft
outside and hard inside. These kinds of calli are easy to differentiate into
plantlets, and they are not the friable type. Friable embryogenic calli could be
obtained by cycled regulated culture on IM1-IM4 medium for 7-8 months from the
original calli. They became vigorous, lightish yellow in color, with small grainy
forms. Well-separated and fast-growing suspending cell lines have been obtained
from the above-mentioned embryogenic calli in the liquid medium. Regenerated
plants have been obtained for this kind of suspension line by culturing on the
medium for differentiation. The surviving percentage for such plantlets was over
95% after planting in the soil.
PMID- 9759544
TI - Selection of EPS-deficient mutants (Exo-) from Rhizobiun huakuii 107 by region
directed Tn5 mutagenesis.
AB - pJB-B5 was a recombinant plasmid of pRK415 containing the 5.9 kb B5 fragment from
exoR'-11. After pJB-B5 was mutagenized by MT614 (mal::Tn5), 10 plasmids TN1-1,
TN1-12, TN2-2, TN2-3, TN3-1, TN4-1, TN9-1, TN10-1, TN13-1, and TN14-1 with
different Tn5 insertions in the B5 fragment were constructed. By conjugation of
TN1-1, etc., into Rhizobium huakuii 107 containing the P-group plasmid pPH1JI
which is incompatible with pRK415, and simultaneous selection for Rifr (conferred
by strain 107), Gm(r) (conferred by pPH1JI), and Nmr (retention of Tn5), R.
huakuii 107 transconjugant yields a strain in which Tn5 has recombined into the
R. huakuii 107 genome. Three EPS-deficient (Exo-) mutants 107 (TN2-2), 107 (TN10
1), and 107 (TN13-1) were isolated and their inserted Tn5 was certified as the
result of a double homologous recombinant event by Southern hybridization
analysis. This result showed the Tn5 region-directed mutagenesis is an efficient
way to select Exo- mutant in R. huakuii.
PMID- 9759545
TI - Batch fermentation and optimization of media for Bacillus thuringiensis.
AB - The composition of No. II medium obtained with shaking cultivation contained
three factors: nitrogen source, carbon source, and inorganic salts. The
relationship between component factors (x(i)) of the media and spore numbers (y)
of Bacillus thuringiensis (Bt) was demonstrated by the orthogonal-rotation
combination test. A response surface equation was formed as follows: y = 384 -
7.245x1 + 11.705x2 + 15.475x3 + 14.039x1(2) + 41.831x2(2) - 79.49x3(2) -
35.375x1x2 - 3.375x1x3 - 106.625x2x3. The results showed that this method is
simple, practical, and rapid enough for selecting fermentation media for Bt. In
addition, the whole course of batch fermentation was also investigated.
PMID- 9759546
TI - Study on kinetics of ergosterol fermentation.
AB - The kinetic relationships among the consumption of sucrose, production of
ergosterol, formation of ethanol, and growth of yeast cells were studied. A two
stage kinetic model was established. The relative deviations between experimental
data and simulated results were no more than 20%.
PMID- 9759547
TI - What is a cystic fibrosis diagnosis?
AB - Cystic fibrosis (CF) should be considered in patients with a wide variety of
clinical presentations and of diverse racial and ethnic backgrounds. In most
cases the diagnosis is suggested by manifestations of chronic sinopulmonary
disease and exocrine pancreatic insufficiency, and then confirmed by a positive
sweat test result. Patients may, however, present with pancreatic sufficiency or
other atypical clinical features, sometimes in association with normal or
borderline sweat test results. In such cases, the ability to detect CF mutations
and to measure transepithelial bioelectric properties can be diagnostically
useful. Mutation analysis can also be used for carrier screening, prenatal
diagnosis, and newborn screening.
PMID- 9759548
TI - Clinical implications of cystic fibrosis transmembrane conductance regulator
mutations.
AB - Cystic fibrosis (CF) phenotypes are determined by mutations in the CF gene,
genetic background, and environment. The nature of the cystic fibrosis
transmembrane conductance regulator (CFTR) mutation determines the extent of
protein function. CFTR mutations that abolish protein function are associated
with severe CF phenotypes. Mutants that retain partial function of CFTR are
associated with mild phenotypes. The effect of CFTR dysfunction is variable in
different tissues. Atypical phenotypes caused by mutations in the CF gene may be
revealed by CFTR mutation analysis and family studies. These phenotypes help to
define the spectrum of clinical manifestations caused by CFTR mutations.
PMID- 9759549
TI - What we know and what we do not know about cystic fibrosis transmembrane
conductance regulator.
AB - The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP
regulated chloride channel that resides in the apical membrane of many epithelial
cells. Channel opening requires phosophorylation of serine residues in an
intracellular regulatory domain by protein kinase A and as the binding and
hydrolysis of ATP by intracellular nucleotide binding domains. Besides conducting
the chloride ion, CFTR also regulates the function of other membrane proteins,
directly or indirectly, notably the outwardly rectifying chloride channel and the
epithelial sodium channel. The disease cystic fibrosis is caused by mutations in
CFTR, which can result in defective protein production, defective processing and
degradation in the endoplasmic reticulum, or defective channel pore properties or
gating properties.
PMID- 9759550
TI - Burkholderia cepacia. Management issues and new insights.
AB - Although Burkholderia cepacia colonizes a relatively small proportion of
individuals with cystic fibrosis (CF), it is associated with significant
morbidity and mortality, and has had a profound impact on infection control
practices. This article reviews the current understanding of the epidemiology of
B. cepacia infection, describes important recent developments in the microbiology
and taxonomy of this species, and presents issues that remain obstacles to
defining the optimal management of B. cepacia infection in CF.
PMID- 9759551
TI - Basic therapies in cystic fibrosis. Does standard therapy work?
AB - Epidemiologic data demonstrate a dramatic improvement in survival for cystic
fibrosis (CF) over the last few decades and projections suggest that trend will
continue. Standard therapy works and should be aggressively applied to this
patient population. Although the specific therapies have evolved over the years,
the basic tenets of CF care remain unchanged and include antibiotics to control
infection, airway clearance, and adequate nutrition. This article focuses on
treatment of the pulmonary disease and includes a discussion of the following
specific components of a standard therapeutic approach to CF: (1) antibiotics,
(2) airway clearance and exercise, (3) mucolytics, (4) bronchodilators, (5)
oxygen, (6) anti-inflammatory therapies, and (7) nutritional support. Judicious
application of these therapies coupled with careful monitoring of pulmonary,
nutritional, and metabolic parameters results in most CF patients surviving into
adulthood with an acceptable quality of life.
PMID- 9759552
TI - Therapies aimed at airway inflammation in cystic fibrosis.
AB - Therapies aimed at decreasing the inflammatory response present a new strategy
for treating cystic fibrosis (CF) lung disease. Alternate day prednisone may be
beneficial, however, unacceptable adverse effects limit long-term use. Inhaled
corticosteroids are under investigation as a safer alternative. High-dose
ibuprofen twice daily has been shown to decrease the progression of CF lung
disease and is without significant toxicity. Other NSAIDs and pentoxifylline and
fish oil are under consideration. Antiproteases and antioxidants are also being
studied. The rationale for all of these agents lies in their potential to
decrease neutrophil influx into the lung, and counteract injurious products of
neutrophils. Adding anti-inflammatory therapy to an already comprehensive
treatment program will hopefully decrease morbidity and improve the quality of
life for patients with CF.
PMID- 9759553
TI - Therapies directed at the basic defect in cystic fibrosis.
AB - There are over 600 unique mutations in the cystic fibrosis (CF) gene that can be
classified in five general categories with respect to specific defect. Through
basic research into the genetic and physiologic consequences of these mutations,
it has become possible to design genotype-specific therapeutic strategies. New
pharmaceutical agents are under development for the rescue of defective cystic
fibrosis transmembrane conductance regulator mRNA or protein. Some of these
compounds are undergoing study in CF patients in Phase I clinical trials. This
article evaluates the current research directed at translating a basic molecular
understanding of the disease into innovative new treatments.
PMID- 9759554
TI - Is DNA destiny? A cure for cystic fibrosis.
AB - Cystic fibrosis (CF) remains an attractive target for cure by gene therapy.
Results from several trials are reviewed in this article and have shown that
mature airway epithelial cells are relatively resistant to gene transfer, that
host immune responses determine the duration of transgene expression and define
the toxicity, and that the efficiency of transfection remains low. Significant
hurdles to the development of gene therapy remain, including the definition of
efficacy endpoints, the ability to produce enough material, and the ability to
dose the entire lung. Nonetheless, invaluable insights into CF and pulmonary
biology have been gained in the gene therapy research effort.
PMID- 9759555
TI - Lung transplantation for cystic fibrosis.
AB - Lung transplantation currently stands as the only therapeutic option that carries
the potential to restore patients with advanced cystic fibrosis to a more normal
state of health. Nonetheless, the procedure carries significant risk and median
survival following transplantation is only 5 years. This article discusses the
currently achievable outcomes and the common short-comings of transplantation.
Strategies to optimize outcomes through appropriate patient selection, use of
living donors, and novel research initiatives are discussed.
PMID- 9759556
TI - Osteoporosis in patients with cystic fibrosis.
AB - Decreased bone density and increased risk of fractures are seen in patients with
cystic fibrosis. Suboptimal vitamin D levels, nutrition problems, hypogonadism,
inactivity, corticosteroid use, and cytokines may contribute to the low bone mass
seen in these patients. Treatment recommendations must be individualized and may
include nutrition, vitamin D, estrogen or testosterone, and exercise. In high
risk patients calcitonin or growth hormone could be considered.
PMID- 9759557
TI - Human Kallikrein 2 (hK2) and prostate-specific antigen (PSA): two closely
related, but distinct, kallikreins in the prostate.
AB - Recent studies on human kallikrein 2 (hK2) have revealed striking similarities
and significant differences with the closely related kallikrein PSA. Both PSA and
hK2 are primarily localized to the prostate and share close structural
similarities. Although both kallikreins are produced by the same secretory
epithelial cells in the prostate, hK2 is associated more with prostate tumors
than PSA and is highly expressed in poorly differentiated cancer cells. The
potent trypsin-like activity of hK2 contrasts with the weak chymotrypsin-like
activity of PSA. The inactive precursor form of PSA, proPSA, is converted rapidly
to active PSA by hK2, suggesting an important in vivo regulatory function by hK2
on PSA activity. The high homology between hK2 and PSA results in significant
cross-reactivity to hK2 by polyclonal and some monoclonal antibodies to PSA.
Future studies on both PSA and hK2 need to take into account this potential for
cross-reactivity. Specific monoclonal antibodies to hK2 have now demonstrated
that serum levels of hK2, like PSA, are correlated with prostate cancer. The
production of hK2 protein in active protease form and specific monoclonal
antibodies to the hK2 antigen will allow extensive future studies delineating the
physiological and clinical utility of this new prostate antigen.
PMID- 9759558
TI - The radiology of the thoracic manifestations of AIDS.
AB - The thoracic manifestations of AIDS have undergone a gradual metamorphosis,
partly due to more awareness about the disease leading to earlier diagnoses and
partly due to the fact that research has produced more effective prophylaxis as
well as treatment for these patients. Many patients now demonstrate partial or
complete clinical response which prolongs the length and quality of life of
individuals positive for the Human Immunodeficiency Virus (HIV+). Also, with the
large number of infected individuals coming to medical attention, and the years
of experience in diagnosing and treating these AIDS patients, we now recognize
not only the usual but also less usual manifestations of thoracic illnesses in
AIDS, including infections, non-infectious diseases such as HIV associated
Lymphocytic Interstitial Pneumonia and the neoplasms associated with AIDS. A
section will be devoted to HIV infection in children. We will finish the article
with a discussion of the current role of Nuclear Medicine in the diagnosis of HIV
associated thoracic diseases. These topics are the subject of this article.
PMID- 9759559
TI - Tannins and human health: a review.
AB - Tannins (commonly referred to as tannic acid) are water-soluble polyphenols that
are present in many plant foods. They have been reported to be responsible for
decreases in feed intake, growth rate, feed efficiency, net metabolizable energy,
and protein digestibility in experimental animals. Therefore, foods rich in
tannins are considered to be of low nutritional value. However, recent findings
indicate that the major effect of tannins was not due to their inhibition on food
consumption or digestion but rather the decreased efficiency in converting the
absorbed nutrients to new body substances. Incidences of certain cancers, such as
esophageal cancer, have been reported to be related to consumption of tannins
rich foods such as betel nuts and herbal teas, suggesting that tannins might be
carcinogenic. However, other reports indicated that the carcinogenic activity of
tannins might be related to components associated with tannins rather than
tannins themselves. Interestingly, many reports indicated negative association
between tea consumption and incidences of cancers. Tea polyphenols and many
tannin components were suggested to be anticarcinogenic. Many tannin molecules
have also been shown to reduce the mutagenic activity of a number of mutagens.
Many carcinogens and/or mutagens produce oxygen-free radicals for interaction
with cellular macromolecules. The anticarcinogenic and antimutagenic potentials
of tannins may be related to their antioxidative property, which is important in
protecting cellular oxidative damage, including lipid peroxidation. The
generation of superoxide radicals was reported to be inhibited by tannins and
related compounds. The antimicrobial activities of tannins are well documented.
The growth of many fungi, yeasts, bacteria, and viruses was inhibited by tannins.
We have also found that tannic acid and propyl gallate, but not gallic acid, were
inhibitory to foodborne bacteria, aquatic bacteria, and off-flavor-producing
microorganisms. Their antimicrobial properties seemed to be associated with the
hydrolysis of ester linkage between gallic acid and polyols hydrolyzed after
ripening of many edible fruits. Tannins in these fruits thus serve as a natural
defense mechanism against microbial infections. The antimicrobial property of
tannic acid can also be used in food processing to increase the shelf-life of
certain foods, such as catfish fillets. Tannins have also been reported to exert
other physiological effects, such as to accelerate blood clotting, reduce blood
pressure, decrease the serum lipid level, produce liver necrosis, and modulate
immunoresponses. The dosage and kind of tannins are critical to these effects.
The aim of this review is to summarize and analyze the vast and sometimes
conflicting literature on tannins and to provide as accurately as possible the
needed information for assessment of the overall effects of tannins on human
health.
PMID- 9759560
TI - Effective regulatory approval process for food ingredient technologies.
AB - Most sciences and technologies related to food safety have advanced exponentially
over the 40 years since passage in the U.S. of the Food Additive Amendment of
1958 to the Federal Food, Drug and Cosmetic (FD&C) Act. Effective regulatory
decision making places a high premium on competent professional and
administrative judgement applied to sound scientific data. This review discusses
changes and lessons learned in the food safety sciences over the last 4 decades.
Other segments of the safety and compliance infrastructure necessary to assure
that the public receives safe and wholesome foods have not kept pace with the new
scientific knowledge. The quality of foods in our marketplace can be improved
only after the regulatory and legislative segments of the infrastructure,
discussed in a companion symposium paper, are brought into better synchrony with
the sciences.
PMID- 9759561
TI - An integrated approach to the development of reduced-fat food emulsions.
PMID- 9759562
TI - [Laser technology in dermatology: quo vadis--science or business?].
PMID- 9759563
TI - [Value of psychotherapy in expert assessment of skin diseases. Recommendations
and indications for additional psychotherapy evaluation in expert assessment from
the viewpoint of dermatology].
AB - Skin diseases, the psyche and psychological changes are often intertwined,
especially in patients presenting for expert dermatologic opinion. In many cases
an additional evaluation provided by psychotherapeutic medicine may be necessary.
This resource may help with the diagnosis, explanation of the problem and
estimation of the degree of disability. The different legal guidelines of the
various evaluation boards must be considered. The role of psychotherapeutic
evaluation is demonstrated through case examples. The evaluation of new possibly
occupationally-related disorders such as multiple chemical sensitivity and
mobbing is considered.
PMID- 9759564
TI - [Amicrobial intertriginous pustulosis in autoimmune diseases--a new entity?].
AB - During the last decade an unusual amicrobial intertriginous pustulosis has been
described in association with autoimmune disease in sixteen female patients. The
clinical hallmark is a sterile pustular dermatosis preferentially located in
intertriginous regions that responds to local or systemic corticosteroids.
Histologic features are subcorneal sometimes spongiform neutrophilic pustules. We
report an additional patient suffering from this unusual dermatosis. An overview
of the patients described to date and a review of the literature are given in an
attempt to delineate this amicrobial intertriginous pustulosis from the known
pustular dermatoses.
PMID- 9759565
TI - [Detection of monoclonal T-cells with TCR gamma PCR in mycosis fungoides].
AB - The monoclonal dominant malignant T cells in mycosis fungoides (MF) carry
identical TCR gamma rearrangements. Their detection is a useful diagnostic tool.
Thus, in routine diagnosis we investigated the occurrence of monoclonal T cells
in skin biopsy samples of MF-patients by TCR gamma-PCR, followed by temperature
gradient gel electrophoresis (TGGE). In 188 out of 208 MF patients, at least one
skin sample with sufficient DNA quality for PCR analysis was obtained. Applying a
consensus PCR for the TCR gamma genes V gamma I and J gamma 1/2, we detected
monoclonal T cells in 122 cases (65%). In the remaining 66 cases, we performed
two multiplex-PCRs, covering rearrangements of the other TCR gamma genes. Here we
found in 11 cases (6%) predominant clonal rearrangements of V gamma II-IV and J
gamma 1/2 and in 2 (1%) those of V gamma I-IV and J gamma P 1/2. In patients with
MF, detecting rearrangements of only V gamma I and J gamma 1/2 is sufficient for
PCR screening analysis. In 53 of the patients (28%) the applied methods revealed
no monoclonal T cells. This may be due to a low cell number, oligoclonal nature,
chromosomal abberations or remaining of TCR in germline configuration.
PMID- 9759566
TI - [Color duplex ultrasound of the finger arteries. An alternative to angiography?].
AB - By means of modern color-coded duplex sonography (CCDS) even very small vessels
can be visualized. Maximum resolution nowadays is about 0.5 mm diameter of the
vessel. We compared the use of CCDS and angiography in studying of acral
perfusion. Besides morphologic criteria, hemodynamic criteria were recorded.
Arteries in healthy fingers appear as long and straight vessels with a clearly
defined border. The physiological maximal blood flow velocity exceeded 20 cm/s.
CCDS revealed tortuosity of finger arteries as typical finding in thrombangiitis
obliterans. Segmental stenosis can either be identified morphologically or
quantified by measurement of the flow velocity with poststenotic maximal systolic
velocities of less than 20 cm/s or by the acceleration of the blood flow within
the stenosis, as proven by angiographic examinations. CCDS is suitable for
evaluation of acral perfusion in patients suffering from secondary Raynaud's
syndrome. Apart from diagnosis of disturbed acral circulation, other possible
applications of CCDS are in in the surgical field, for example replantations in
hand or finger surgery.
PMID- 9759567
TI - [Edematous swelling of the eyelids caused by contact allergy].
AB - Cosmetics and ophthalmological topical preparations are the main causes of
allergic contact eczema about the eye. In most cases, clinical signs are
conjunctival injection, blepharitis, periorbital dermatitis and edema of lids,
often combined with itching. Pure edematous swelling of the eyelids should not
immediately be blamed on a contact allergy, but sufficiently evaluated to exclude
a benign or malignant process of the eyelids, orbita, lacrimal duct and paranasal
sinus. We present a patient with pure edematous swelling of the eyelids due to a
contact allergy by the sympathicomimetic phenylephrine hydrochloride, an uncommon
allergen.
PMID- 9759568
TI - [Syringocystadenoma papilliferum and trichoblastoma within a sebaceous nevus].
AB - Since birth, a 43 year-old man displayed a nevus sebaceus on the right temple.
The histopathology revealed two distinct adnexal neoplasms associated with this
lesion: a syringocystadenoma papilliferum and a trichoblastoma. We describe the
combination of these entities in this report.
PMID- 9759569
TI - [Sclerosing in multiple familial glomangiomas].
AB - Glomus tumors (glomangiomata) are benign tumors arising from glomus cells.
Multiple glomangiomata are less frequent and less painful than the solitary
variant, which is usually located subungually. Nonetheless multiple glomangiomata
-sometimes being sensitive to pressure and changes in temperature--may cause
considerable discomfort. Treatment of multiple glomangiomata is problematic
because of the often large number of tumors. Sclerotherapy represents an
alternative to surgical and cryosurgical therapy. We report on sclerotherapy in a
35 year old female patient with multiple hereditary glomus tumors.
PMID- 9759570
TI - [Neonatal lupus erythematosus and maternal HELLP syndrome: is there a
pathogenetic link?].
AB - A newborn boy developed annular erythematous lesions on his entire body.
Histopathological examination showed typical features of lupus erythematosus. His
mother was positive for anti-Ro/SSa and anti-La/SSb antibodies. Neonatal lupus
erythematosus was diagnosed. During pregnancy the mother had suffered from HELLP
syndrome. The reported case points out the necessity to differentiate HELLP
syndrome from first manifestation of lupus erythematosus during pregnancy. A
direct causal relationship between neonatal lupus erythematosus and HELLP
syndrome of the mother seems to be unlikely.
PMID- 9759572
TI - [Isotretinoin in inflammatory bowel diseases].
PMID- 9759571
TI - [Erythrokeratodermia progressiva symmetrica Darier-Gottron with generalized
expression].
AB - A mother and her son presented with erythrokeratodermia progressiva symmetrica
Darier-Gottron. Both patients developed symmetrical erythematous and
hyperkeratotic plaques on the extremities and face at the age of 6 months. At the
age of 2 1/2 years the son suffered from rapid progression of the disease to
involve the entire skin. The disease of his mother had shown a similar course,
however, with spontaneous regression at the age of 10 years. The clinical
features of this generalized condition were identical to congenital lamellar
ichthyosis. Light microscopy was non-specific with orthohyperkeratosis, focal
parakeratosis and acanthosis. Electron microscopy revealed numerous keratinosomes
in the stratum granulosum, keratinosome-derived lamellae in the intercellular
space and partly augmented keratohyalin with clumping. In the stratum spinosum
short tonofilament bundles with clumping were remarkable. The child experienced a
significant and persistent improvement with systemic retinoids. His mother's
disease was successfully controlled with intermittent retinoid therapy. With the
clinical and ultrastructural criteria presently available, an unambiguous
differentiation between erythrokeratodermia progressiva symmetrica, usually a
localized disorder of keratinization, however with intermittent generalization,
and other disorders of keratinization seems difficult.
PMID- 9759573
TI - [Antihistaminics. I].
PMID- 9759574
TI - Issues in the epidemiology of melanoma.
AB - Malignant melanoma imposes a considerable public health burden. Both incidence
and mortality have increased many fold over the past several decades, although
current trends suggest possible change in the prior patterns. Etiologic factors
have been established, of which the most important is intense sun exposure.
Primary prevention and early detection are both potentially critical in reducing
the burden of melanoma. Much remains to be clarified in our management of this
disorder on a population basis, and methodologic difficulties are plentiful. The
potential for substantial reductions in melanoma mortality requires that we
address the difficulties so that maximally effective public health initiatives
may be undertaken.
PMID- 9759575
TI - Clinical recognition of melanoma and its precursors.
AB - This article reviews the essential clinical features of cutaneous melanoma, as
well as those of the more common benign pigmented lesions that need to be
distinguished on clinical examination.
PMID- 9759576
TI - Pathologic parameters in the diagnosis and prognosis of primary cutaneous
melanoma.
AB - Significant progress has been made in the last 10 years on the identification of
histologic parameters that are independent predictors of melanoma prognosis,
immunohistochemical markers of cells of melanocytic origin and changes in
adhesion molecules, cytoskeletal proteins, growth factor receptors, cell
signaling, and nuclear proliferation proteins associated with tumor progression.
Histologic criteria may never be completely sufficient to predict behavior
accurately, because the fundamental change that renders a cell aggressive may not
be morphologically reflected and may require immunohistochemical or other
molecular markers to establish behavior. To date, it is humbling that no
immunohistochemical or molecular marker provides a greater predictable value for
aggressive behavior than does the simple calibrated ocular micrometer to measure
tumor thickness. Nevertheless, development of multiple histologic parameters with
the concept of nontumorigenic RGP and tumorigenic VGP provides a reliable
statistical model to predict metastases. Fortunately, nontumorigenic RGP
melanomas with greater than 75% regression are rare. Thus, individual patients
with melanoma without regression and without the tumorigenic VGP can be given
reasonable assurance of 100% survival. Nevertheless, this assurance is based on a
statistical model with a finite population studied. Additional studies are needed
to confirm this model, as well as more definitive markers to precisely predict
outcome for those individuals with tumorigenic VGP melanoma.
PMID- 9759577
TI - Classification and staging of melanoma.
AB - Although a standardized and uniformly accepted cancer staging system is an
essential and fundamental requirement to enable meaningful comparisons across
patient populations, the sometimes capricious biologic behavior of melanoma makes
developing such a staging system particularly difficult. Since the earliest well
documented attempts at classifying patients with cutaneous melanoma were
described more than 50 years ago, the identification of increasingly powerful
prognostic factors has led to sequential modifications of the cutaneous melanoma
staging system. The current AJCC staging system is based on relatively well
established prognostic factors; however, several recent reports have identified
additional prognostic factors not included in the current system, and other
studies support the re-evaluation of some of the currently employed staging
criteria. Some of the more controversial areas include the relevance of level of
invasion versus tumor thickness, optimal cutoffs for tumor thickness, importance
of ulceration, the grouping of satellites with in-transit metastases, the
inclusion of microsatellites and local recurrences as a separate staging
criterion, the replacement of size of nodal mass with number of positive nodes,
the importance of nodal metastases in more than one nodal basin, and the
prognostic significance of distant metastases. Therefore, future modifications of
the staging system are anticipated to better incorporate these observations.
Stage-specific staging recommendations for the patient with melanoma provide the
clinician with a framework to most efficiently assess extent of disease in an era
of cost-conscious clinical practice. In the asymptomatic patient with primary
melanoma (stage I or II), we recommend a chest roentgenogram and evaluation of
alkaline phosphatase and LDH levels; extensive radiologic evaluations are not
indicated, because the rate of detection in this population is extremely low.
Additional staging information should also be obtained by the technique of
lymphatic mapping and sentinel lymphadenectomy. For patients with local-regional
disease (stage III, satellites, and local recurrence), a selective approach to
imaging studies is warranted. For this patient population, we recommend complete
blood count, liver function tests including alkaline phosphatase and LDH, a chest
roentgenogram, and a CT scan of the abdomen. Although the yield of these tests,
particularly CT of the abdomen, in detecting distant metastases in asymptomatic
patients is low, they may identify false-positive abnormalities and provide an
important baseline for future studies in this high-risk population. For patients
with disease below the waist or in the head and neck region, we recommend CT of
the pelvis and CT of the neck, respectively. Additional studies should be done
only if clinically indicated. Finally, patients with known systemic disease
(stage IV) should be more comprehensively evaluated, because the likelihood of
detecting asymptomatic metastases is higher. Accordingly, in addition to the work
up outlined previously for stage III patients, we also perform a CT scan of the
chest and MR imaging of the brain; other studies (e.g., bone scan,
gastrointestinal series) are performed on the basis of symptoms.
PMID- 9759578
TI - Prognosis in malignant melanoma.
AB - A uniform and practical classification and staging system for melanoma must exist
and be widely adopted if useful comparisons between different treatment centers
and databases are to be made. This article reviews the 1992 American Joint
Committee on Cancer pTNM staging system. In this classification, localized
disease without regional nodal involvement is defined as stage I or II, depending
on the tumor thickness of the primary melanoma. Regional lymph node involvement
and/or in-transit metastasis is defined as stage III, and systemic metastatic
disease is defined as stage IV.
PMID- 9759579
TI - The surgical treatment of primary melanoma.
AB - Local control is paramount to the clinical management of melanoma. A general
consensus has been reached regarding the surgical treatment of primary malignant
melanoma. By means of well-designed, multi-institutional, prospective, and
randomized trials, the margins of excising the primary melanoma have been reduced
considerably since the initial guidelines set out by W. S. Handley in 1907. The
margins of excision now recommended are designed to limit the risk of local
recurrence with its potential effect on survival and achieve the optimal cosmetic
outcome. These margins are modified according to particular anatomic site
constraints.
PMID- 9759580
TI - Lymphatic mapping and selective lymphadenectomy as an alternative to elective
lymph node dissection in patients with malignant melanoma.
AB - This article reviews the use of selective lymphadenectomy, otherwise known as
sentinel lymph node biopsy, as a clinical alternative in patients with malignant
melanoma. This represents a compromise between the two traditional treatment
modalities, elective lymph node dissection or observation of the regional nodal
basin followed by therapeutic lymph node dissection once disease becomes
clinically apparent.
PMID- 9759581
TI - Adjuvant interferon treatment for melanoma.
AB - After decades of research, the adjuvant therapy of patients with melanoma has
recently shown significant survival and relapse-free interval benefit for the
intravenous and subcutaneous administration of maximally tolerable dosages of
recombinant IFN alpha 2b in a trial conducted by the ECOG (E1684). Despite the
toxicity of this therapy, retrospective analyses of its impact upon quality-of
life using Q-TWiST methods and cost-efficacy analyses all argue for the benefit
and utility of this intervention, especially for node-positive patients with
resectable melanoma at highest risk of relapse. A confirmatory trial has been
completed and will mature in the spring of 1998. The impact of lower dosages of
IFN, apparent transiently during and for a period of time following treatment has
not been sustained with longer follow-up in a number of trials. Current
approaches in Europe and North America focus upon refinement of dose and duration
of treatment with IFN and their potential interactions with, and comparison with,
active specific immunotherapy with vaccines. A recently emerging area of research
is the patient with stage IIA melanoma and the potential role of an abbreviated
high-dose regimen of IFN alpha in this patient subset.
PMID- 9759582
TI - Vaccines and other adjuvant therapies for melanoma.
AB - Patients with thick primary melanomas or regional lymph node involvement are at
high risk of relapse. Investigations of adjuvant therapy over the past 30 years
show only one significantly positive trial employing high dose interferon-alpha
2b. This is a potentially toxic regimen, therefore, other better-tolerated forms
of adjuvant immunotherapy are being studied. Recent advances in basic science
have led to a better understanding of the T-cell response to human cancer. This
article discusses the background and current clinical trials of active specific
immunotherapies for melanoma, including peptide and ganglioside vaccines.
PMID- 9759583
TI - The evolution of the role of radiation therapy in the management of mucocutaneous
malignant melanoma.
AB - The role of radiation therapy in the treatment of malignant melanoma has evolved
substantially over time. Years ago, malignant melanomas were generally considered
radioresistant. Over time, the palliative value of radiation therapy was
established. Most recently it also has become clear that judiciously applied
therapy may be curative in either an adjuvant setting or for small-volume
disease.
PMID- 9759585
TI - Immunotherapy and experimental approaches for metastatic melanoma.
AB - This article reviews the clinical investigations involving recombinant cytokines
(either alone or in combination with adoptive immunotherapy, toxicity reduction
agents, or cytotoxic chemotherapy), vaccines, monoclonal antibodies or antibody
conjugates, and gene therapy. These various approaches are reviewed for their
current and potential roles in curing metastatic melanoma.
PMID- 9759584
TI - Systemic treatment of metastatic melanoma with chemotherapy.
AB - This article reviews the use of systemic chemotherapy for the treatment of
metastatic melanoma, including single-agent chemotherapy, combination
chemotherapy with and without tamoxifen, and biochemotherapy.
PMID- 9759586
TI - Public health interventions for melanoma. Prevention, early detection, and
education.
AB - Worldwide melanoma control programs that include some combination of primary
prevention, education, and screening activities have only recently begun to
undergo an evaluation process. More studies with rigorous design and evaluation
are needed. Until then, the proper public health policy guidelines for melanoma
control, especially screening, are open to debate. Future studies must determine
how screening, early detection, case finding, and education can best be used to
reduce mortality and achieve optimal melanoma control.
PMID- 9759587
TI - American gastroenterology at the end of the millennium and beyond.
PMID- 9759588
TI - Preillness non dietary factors and habits in inflammatory bowel disease.
AB - AIM: Environmental as well as genetic factors play a role in the pathogenesis of
inflammatory bowel diseases. The effects of smoking and diet have been
demonstrated. Other factors have not been extensively investigated. PATIENTS:
Preillness non dietary habits and factors were studied in 88 patients with recent
onset of inflammatory bowel diseases (55 with ulcerative colitis and 33 with
Crohn's disease) and in matched 76 population and 68 clinic controls. RESULTS: No
significant differences were found in relation to education, housing, birth
weight, breast feeding in infancy and current weight. The current body mass index
was significantly lower in patients as compared to clinic controls (p < 0.05).
More patients had low levels of physical activity during the preillness period as
compared to controls (p < 0.001 vs clinic controls), while more controls engaged
in moderate (p < 0.05) or high levels of physical activity in the corresponding
periods. Patients spent fewer hours in strenuous physical activity as compared to
controls (NS). Patients slept fewer hours per day (p < 0.05 vs clinic controls).
More patients than controls experienced stressful life events during the year
prior to onset of symptoms (p < 0.05 for patients with Crohn's disease against
both controls and all patients vs population controls). CONCLUSIONS: Other
environmental factors besides smoking and diet may affect the pathogenesis of
inflammatory bowel disease.
PMID- 9759589
TI - Stress and physical activity: are they risk factors for IBD?
PMID- 9759590
TI - Beclomethasone dipropionate (3 mg) enemas combined with oral 5-ASA (2.4 g) in the
treatment of ulcerative colitis not responsive to oral 5-ASA alone.
AB - BACKGROUND/AIMS: Beclomethasone dipropionate is one of the topical
corticosteroids which appear to have minimal systemic effects. We evaluated
whether combined therapy with Beclomethasone dipropionate enemas and oral 5
aminosalicylic acid could be effective in patients suffering from ulcerative
colitis not responsive to oral 5-aminosalicylic acid as monotherapy. PATIENTS: In
twenty patients, non responders to 5-aminosalicylic acid treatment (2.4-3.6
g/day) given for at least 6 weeks, Beclomethasone dipropionate enemas (3 mg/60
ml/day) were added for 4 weeks. METHODS: Efficacy of the combination was
evaluated before and at the end of the treatment using a clinical, endoscopic and
histological score. RESULTS: After a four-week treatment period, a significant
clinical improvement in stool frequency (p < 0.01), stool consistency (p <
0.001), blood (p < 0.001) and mucus in stools (p < 0.05), was observed. Endoscopy
and biopsy confirmed an improvement in the activity score at the end of the
treatment (p < 0.001). Six patients (30%) achieved remission, ten patients showed
an improvement (50%) and four (20%) showed no benefits. No adverse event was
observed. CONCLUSIONS: Beclomethasone dipropionate enemas combined with oral 5
aminosalicylic acid may be a safe and useful therapeutic approach in the
treatment of ulcerative colitis not responsive to oral 5-aminosalicylic acid
alone.
PMID- 9759591
TI - Optimizing strategies in refractory ulcerative colitis.
PMID- 9759592
TI - Nicotine carbomer enemas--pharmacokinetics of a revised formulation.
AB - AIMS: Ulcerative colitis is predominantly a disease of non-smokers, and
transdermal nicotine has therapeutic benefit but causes frequent side-effects. We
have previously developed a topical enema combining nicotine with a polyacrylic
carbomer; pharmacokinetic parameters were similar in healthy volunteers and
patients with active ulcerative colitis. This enema was reformulated to reduce
and delay nicotine absorption, thereby improving tolerance. METHOD:
Pharmacokinetic observations and side-effects with both formulations are compared
in the same 8 healthy volunteers--all non-smokers, 3 male, mean age 33 years. Six
milligrams of nicotine were complexed with 400 mg of carbomer in a 100 ml liquid
enema. The original formulation was buffered with potassium/phosphate to pH 5.5,
kinematic viscosity was 3 mNm; the revised preparation incorporated trometamol 1%
solution to buffer to pH 4.2, viscosity 5 mNm. All subjects had the two
formulations on separate occasions at least a month apart, with serial blood
measurements and side-effect profile recorded for 8 hours. RESULTS: The revised
enema formulation significantly reduced Cmax for nicotine from 8.3 +/- 2.7 to 6.6
+/- 2.1, p = 0.03 with some reduction in nicotine absorption and improved
tolerance. Although there was considerable intersubject variation in profiles for
nicotine and cotinine, they were similar for each subject on both occasions.
CONCLUSIONS: The lower pH and greater viscosity reduced the amount of free
nicotine in its unionised form available for absorption, but made it possible to
expose colonic mucosa to the same nicotine dose. In other drug formulations where
side-effects are a limiting factor these modifications may also be relevant.
PMID- 9759593
TI - Plasma levels of endothelin-1 in patients with Crohn's disease and ulcerative
colitis.
AB - AIM: The purpose of this study was to investigate the behavior of circulating
endothelin-1, a vasoconstrictor and mitogenic peptide, in patients with
inflammatory bowel disease. PATIENTS: We investigated plasma endothelin-1 levels
in 29 patients with Crohn's disease, 13 with ulcerative colitis and 26 healthy
subjects as controls. METHODS: Erythrocyte sedimentation and C-reactive protein
were also measured in all patients. Plasma endothelin-1 was measured by specific
radioimmunoassay and expressed as pg/ml. RESULTS: Both Crohn's disease and
ulcerative colitis patients showed a significant increase in plasma endothelin-1
concentration (22.3 +/- 8.2 pg/ml and 11.2 +/- 2.7 pg/ml, respectively) when
compared to healthy subjects (6.2 +/- 1.5 pg/ml). Moreover, plasma endothelin-1
levels were significantly higher in Crohn's disease patients than those in
ulcerative colitis patients (22.3 +/- 8.2 pg/ml vs 11.2 +/- 2.7 pg/ml; p < 0.001,
respectively). A weak correlation (r = 0.645; p < 0.013) between erythrocyte
sedimentation and endothelin-1 levels was observed in Crohn's disease patients.
Age, sex, clinical activity of the disease, duration of history, anatomical
localization of disease and therapy had no influence on plasma endothelin-1
levels. CONCLUSION: Our results show that plasma endothelin-1 levels increase in
chronic inflammatory bowel disease and mainly in Crohn's disease. This
observation leads us on to believe that endothelin-1 has a important role in
inflammatory bowel disease.
PMID- 9759594
TI - Use of the stable isotope 65Cu test for the screening of Wilson's disease in a
family with two affected members.
AB - BACKGROUND/AIMS: An improved method for the study of copper metabolism in
Wilson's disease, using a stable, rather than radioactive, copper isotope (65Cu)
has recently been described. We report on the use of this method for the study of
a family with two members affected by Wilson's disease. SUBJECTS: The family
comprised parents and four siblings: one 20-year-old male and three females, aged
22, 17 and 5 years, respectively. The boy and the 17-year-old girl both presented
with liver cirrhosis. Diagnosis of Wilson's disease was suggested by elevated
liver copper content and/or low caeruloplasmin levels and Kayser-Fleischer ring.
METHODS: All family members were given an oral dose of 3 mg of 65Cu. Blood
samples were taken at 0, 1, 2, 6, 24, 48, and 72 hours. In 4 subjects, additional
blood samples were drawn at 7, 14 and 21 days after dosage. The ratio 65Cu:63Cu
in serum was determined in all samples by means of Inductively Coupled Plasma
Mass Spectrometry. RESULTS: The diagnosis of Wilson's disease was confirmed in
the two symptomatic members by the unequivocal decrease observed in the 65Cu
percent enrichment, which approached zero by 72 hours. In contrast, Wilson's
disease could be definitely excluded in both siblings, one of whom only 5 years
old, on the evidence of net secondary peaks, showing normal incorporation of 65Cu
into caeruloplasmin. These findings were later confirmed by genetic analysis.
Parents, who carried defective genes with different mutations, also showed
different abnormalities of copper metabolism. CONCLUSIONS: The oral test with the
stable copper isotope 65Cu is a safe, non invasive option able to exclude
Wilson's disease in patients with a difficult diagnosis or in a presymptomatic
stage. However, positive tests must still be confirmed by copper dosage in liver
biopsies, as heterozygotes can present with severe alterations of copper
metabolism, without developing symptoms of the disease. The use of this test in
conjunction with genetic analysis on a larger number of heterozygous subjects may
add to the understanding of the Wilson's disease defect.
PMID- 9759595
TI - Updating prognosis of cirrhosis by Cox's regression model using Child-Pugh score
and aminopyrine breath test as time-dependent covariates.
AB - BACKGROUND AND AIMS: The determination of aminopyrine breath test on entry into
the study was recently shown to improve the accuracy of prediction of death based
on the Child-Pugh classification, but the possible usefulness of serial
determinations of both parameters has not been assessed. In the present study, we
aimed at evaluating whether serial determinations of aminopyrine breath test and
Child-Pugh score improve prognostic accuracy in patients with cirrhosis, compared
with determinations obtained only on admission. PATIENTS: In 74 patients with
liver cirrhosis aminopyrine breath test and Child-Pugh score were obtained upon
entry into the study. Patients were followed with sequential aminopyrine breath
tests and assessments of the Child-Pugh score every 4-6 months. A total number of
232 determinations were obtained. During follow-up 45 patients died, on average
after 12 months of follow-up. RESULTS: Child-Pugh score improved in the beginning
of follow-up, and then remained fairly constant; aminopyrine breath test showed
no improvement in the beginning of follow-up, but rather a slowly progressive
decline. In patients who died, both the Child-Pugh score and the metabolism of
aminopyrine were significantly more impaired in the last year preceding death (p
< 0.05). Applying Cox's regression model with time-dependent covariates, Child
Pugh score and aminopyrine breath test were independent significant predictors of
survival. The model with time-dependent covariates explained the observed
survival much better than the model with time-fixed covariates (chi-sq. explained
by regression = 31.45 vs 11.97; d.f. = 2; p = 0.0000001 vs 0.003). CONCLUSIONS:
These data suggest that serial determinations of Child-Pugh score and aminopyrine
breath test can be used to efficiently update prognosis of cirrhosis.
PMID- 9759596
TI - Does repetition of quantitative liver function tests improve prognosis accuracy
of patients with chronic liver disease?
PMID- 9759597
TI - Need and supply of liver grafts in Tuscany.
AB - BACKGROUND: Epidemiological data are fundamental to adequately plan the activity
of a liver transplantation centre. AIM: To evaluate the ratio between need and
supply of liver grafts in Tuscany and to develop a regional strategy aimed at
increasing donor recruitment. METHODS: The need for liver grafts was estimated on
the basis of an epidemiological study: 19 Medical Units were requested to fill in
a questionnaire inquiring into all Tuscan patients evaluated for liver disease
during three different periods of one month each in 1996. The information
collected was matched with the selection criteria currently employed at our
centre and the patients were classified into the following four categories: 1.
current transplantation candidates; 2. future transplantation candidates; 3.
candidates not suitable on account of age; 4. candidates not suitable on account
of exclusion criteria. The number of liver donors was obtained from the donor
registry. RESULTS: Questionnaires were returned for a total of 452 patients: 27
(5.97%) were classified as current transplantation candidates, 62 (13.72%) as
future transplantation candidates and 19 (4.20%) as candidates not suitable on
account of age. The annual incidence and prevalence of transplantation candidates
were 14.7 and 30.6 cases per million inhabitants, respectively. If age (> or = 61
years) was not considered in the exclusion criteria, the annual prevalence of
transplantation candidates reached 52.1 cases per million inhabitants. During the
same period there were 44 organ donors (12.2 donors per million inhabitants) of
whom 33 were suitable for liver donation (9.3 liver donors per million
inhabitants). To reduce this discrepancy a new programme for organ recruitment,
based upon the Spanish model, has been recently employed. CONCLUSIONS: The annual
need for liver grafts in Tuscany largely exceeds the number of donors currently
available. It is hoped that the new regional programme for organ recruitment will
improve these figures.
PMID- 9759598
TI - Serum interleukin 6 in the prognosis of acute biliary pancreatitis.
AB - BACKGROUND: Data concerning the interleukin 6 pattern in acute biliary
pancreatitis are lacking. AIM: To define the best cut-off point of this molecule
in differentiating the severe form of acute biliary pancreatitis from the mild
form and to evaluate its sensitivity, specificity and diagnostic accuracy in the
prognosis of acute biliary pancreatitis in comparison with those of serum C
reactive protein. PATIENTS: Forty-four patients with acute biliary pancreatitis:
27 patients with mild pancreatitis and 17 with the severe form of the disease.
METHODS: Serum interleukin-6 and C-reactive protein concentrations were assessed
in all patients on admission and for the following 5 days. RESULTS: Serum
interleukin-6 levels were significantly higher (p < 0.02) in patients with severe
acute biliary pancreatitis than in those with the mild form of the disease. No
significant difference in serum C-reactive protein levels was found in the first
2 days in patients with mild biliary pancreatitis when compared to those with the
severe form of the disease. Using a cut-off point of 2.7 pg/ml for serum
interleukin-6 and 11 mg/dl for serum C-reactive protein, the sensitivity of the
two molecules in assessing the severity of acute pancreatitis on the first day of
the study was 87.5% for interleukin-6 and 6.3% for C-reactive protein, the
specificity, 83.3% for interleukin-6 and 91.7% for C-reactive protein, and the
accuracy 85.0% for interleukin-6 and 57.5% for C-reactive protein. CONCLUSIONS:
Serum determination of interleukin-6 in the first 24 hours of the disease is a
better marker of the severity of acute biliary pancreatitis than C-reactive
protein.
PMID- 9759599
TI - Early parameters of prognosis in acute pancreatitis--can cytokine measurements
fulfil their promise?
PMID- 9759600
TI - Endoscopic retrograde cholangiopancreatography in patients with Billroth II
gastrectomy.
AB - AIM: Endoscopic retrograde cholangiopacreatography and associated therapeutic
procedures are widely used in routine clinical practice. The changes in the upper
gastrointestinal anatomy after a Billroth II anastomosis may present technical
difficulties at endoscopic retrograde cholangiopacreatography. METHODS AND
PATIENTS: The case records of all patients who underwent endoscopic retrograde
cholangiopacreatography at our Unit from January 1985 to December 1995 were
reviewed. All patients who had had a previous Billroth II anastomosis or
gastroenteroanastomosis were included in this analysis. Of the 5994 procedures
performed, 124 patients with Billroth II surgery and 10 with a
gastroenteroanastomosis were identified. RESULTS: In these patients, the papilla
was located in 89% of cases from 1985 to 1990 and in 100% of cases from 1991 to
1995. Overall, the success rates for pancreatography, cholangiography, and
endoscopic sphincterotomy were 94%, 97.7%, and 100%, respectively. The morbidity
and mortality rates were 7.4% and 0%, respectively. CONCLUSIONS: The success rate
for endoscopic retrograde cholangiopacreatography in patients with Billroth II
gastrectomy is similar to that of a normal population.
PMID- 9759601
TI - Endoscopic pancreaticobiliary procedures in patients with a Billroth II
resection: a 10-year follow-up study.
AB - BACKGROUND: Previous gastrectomy may present technical difficulties for the
endoscopist, but the problem appears to be decreasing. AIM: To assess endoscopic
retrograde cholangiopancreatography and endoscopic papillotomy in Billroth II
patients compared to similar material acquired 10 years ago. MATERIAL AND
METHODS: We compared a five-year series of patients submitted to Billroth II to a
similar series at our two hospitals obtained 10 years ago. The techniques applied
were mostly unchanged, although stent-assisted needle knife papillotomy was
successfully introduced during the last year. RESULTS: Endoscopic retrograde
cholangiopancreatography was successful in 123 out of 138 patients (89%),
requiring a total of 206 procedures to complete diagnostic and therapeutic goals.
Endoscopic papillotomy was successful in 81 out of 87 cases (93%). Additional
procedures were performed in 40 of the patients. Two duodenal perforations
occurred. Compared to ten years ago, total numbers were almost unchanged, but the
proportion of patients with a therapeutic indication increased from 34% to 63%.
CONCLUSION: There is still need for the special endoscopic retrograde
cholangiopancreatography competence that Billroth II anatomy requires, and the
special techniques described here should be available in at least some referral
endoscopy centres.
PMID- 9759602
TI - ERCP and endoscopic sphincterotomy in Billroth II patients: a demanding technique
for experts only?
PMID- 9759603
TI - Flutamide-induced acute hepatitis: investigation on the role of immunoallergic
mechanisms.
AB - Flutamide is a nonsteroidal antiandrogen drug used in the treatment of prostatic
cancer. Hepatotoxic reactions due to flutamide have been reported with an
incidence ranging from 1% to 5%. These reactions are usually reversible upon
withdrawal of the drug but can occasionally be life-threatening. The mechanism of
flutamide-associated hepatotoxicity is not well established. We report a case of
a 69-year-old man with prostatic carcinoma in whom flutamide induced an acute
hepatitis which resolved completely soon after drug withdrawal. In this patient,
we have studied the possible involvement of an immunological mechanism in causing
flutamide hepatitis by investigating the presence of circulating antibodies
directed against reactive metabolites of flutamide bound to liver proteins with
enzyme-linked immunosorbent assay technique. Although, in the present case, we
have failed to detect IgG reacting with rat liver microsomes incubated in vitro
with flutamide, this does not completely rule out the possibility of an
immunological involvement in flutamide hepatotoxicity. The possibility of severe
flutamide-related injury, independently of the underlying pathogenic mechanism,
strongly suggests the need for careful monitoring of liver enzymes in patients
taking this drug.
PMID- 9759604
TI - Ritodrine-related liver injury. Case reports and review of the literature.
AB - beta-sympathicomimetic ritodrine chloridrate is a commonly used tocolytic agent
for the treatment of preterm labour. Previous reports have described the
occurrence of liver test abnormalities during ritodrine administration but the
clinical significance and incidence of this side effect are still unclear. We
report on two cases including one with a positive rechallenge of liver injury
during oral ritodrine administration and a review of the literature.
PMID- 9759605
TI - The case for case reports.
PMID- 9759606
TI - Haemodynamics and fluid retention in liver disease.
AB - Patients with cirrhosis and portal hypertension exhibit characteristic
haemodynamic changes with a hyperkinetic systemic circulation, an abnormal
distribution of the blood volume and neurohumoral dysregulation. Their plasma and
noncentral blood volumes are increased, but the central and arterial blood volume
and systemic vascular resistance are decreased. A systemic and splanchnic
vasodilatation is of pathogenic importance to the low systemic vascular
resistance and abnormal volume distribution. These are important elements in the
development of the low arterial blood pressure and hyperkinetic circulation in
cirrhosis. Various vasodilators such as nitric oxide, calcitonin gene-related
peptide, and adrenomedullin are among potential candidates in the vasodilatation
in cirrhosis. Besides reflex induced enhanced sympathetic nervous activity,
activation of the renin-angiotensin-aldosterone system, and elevated circulation
vasopressin, endothelin-1 may also be implicated in the haemodynamic counter
regulation in cirrhosis. Recent research has focused on the assertion that the
haemodynamic and neurohumoral abnormalities in cirrhosis are part of a general
circulatory dysfunction, influencing the course of the disease with reduction of
kidney function and sodium-water retention as the outcome.
PMID- 9759607
TI - "Breakthrough" during interferon therapy for chronic hepatitis C. Overview on the
diagnosis, possible aetiology and recommendations for management.
AB - A relapse of serum aminotransferase levels after complete normalisation during
alpha interferon therapy for chronic hepatitis C is diagnosed as Breakthrough.
Its prevalence ranges between 14% and 21% of the responders, with no significant
differences between the alpha interferons. Hepatitis C virus genotype and
interferon dose do not seem to represent predisposing factors. The development of
neutralising antibodies to interferon is associated with Breakthrough in about
half of the patients; other aetiologic factors such as down-regulation of
interferon receptors or development of virus resistance to interferon may be
implicated in the remaining cases. The therapeutic switch from recombinant to
lymphoblastoid alpha interferon has been demonstrated to be a successful strategy
to overcome Breakthrough and to restore a complete response.
PMID- 9759608
TI - Current concept of the role of monocytes/macrophages in inflammatory bowel
disease--balance of proinflammatory and immunosuppressive mediators.
AB - Macrophages are important in providing the first line of intestinal defence
against microorganisms or toxins that break the epithelial barrier, by presenting
antigen to sensitised T cells and releasing a variety of cytokines and
inflammatory mediators. During active states in inflammatory bowel disease, large
numbers of monocytes leave the bloodstream and migrate into the inflamed mucosa
and submucosa. Phenotypic studies have previously shown the presence of much more
marked macrophage heterogeneity in inflammatory bowel disease mucosa than in
normal mucosa. In both Crohn's disease and in ulcerative colitis, distinct
macrophage populations have been found, being prominent in active disease, but
absent from normal mucosa. Studies in our institution have shown that the Ca(2+)
binding proteins MRP8 and MRP14 as well as their heterocomplex MRP8/14 (27E10
epitope) are expressed in the majority of granulocytes and macrophages in active
but not inactive inflammatory bowel disease. Furthermore, a strong complex
MRP8/14 immunoreactivity was present in epithelial cells of the terminal ileum
adjacent to ulcerative and fissuring lesions, while epithelial cells of large
bowel tissues were consistently negative. In vitro studies revealed that
interleukin-13, interleukin-10 and interleukin-4 strongly suppress secretion of
different monocytic proteins. A combination of TH2-cytokines even at suboptimal
concentrations significantly suppressed protein secretion, much more than using
interleukin-13, interleukin-10 or interleukin-4 at a double concentration alone.
Our morphological findings demonstrate the presence of MRP8/14 (27E10 antigen)
both in monocytes/macrophages and in epithelial cells in active inflammatory
bowel disease. Systemic or topical application of combined cytokine treatment
might be a new effective therapeutic approach for chronic inflammatory bowel
disease especially in those cases in which monocytes/macrophages lose their
ability to respond, to some degree, to anti-inflammatory cytokines.
PMID- 9759609
TI - The emerging impact of phage display technology in thrombosis and haemostasis.
PMID- 9759610
TI - The prothrombin 20210A allele is the most prevalent genetic risk factor for
venous thromboembolism in the Spanish population.
AB - We investigated the prevalence of the new recently reported mutation in the
prothrombin gene (20210 A) in a sample of 116 unrelated patients with venous
thromboembolism. We found 20 heterozygous carriers (17.2%, CI 95% 10.4-21.1). In
comparison, we observed 13 carriers among 201 healthy unmatched controls (6.5%,
CI 3.5-10.8). The 20210 A mutation seems to increase the risk of venous
thrombosis 3-fold (odds ratio 3.1, 95% CI 1.4-6.6). Considering only patients
with a first event (n = 62) the OR was 2.0 (p = 0.18, NS) while those with
recurrent events (n = 54) showed an OR of 5.9 (95% CI 2.5-14.4). A majority of
heterozygous patients (55%) presented a second thrombophilic factor and 60% of
affected females had their first event before 30 years of age, while on oral
contraceptive treatment. The prevalence found in this study for healthy people is
the highest reported to date. The 20210 A variant appears to be the most
prevalent genetic risk factor among patients with thrombosis in our geographical
area.
PMID- 9759611
TI - Treatment with a GPIIb/IIIa antagonist inhibits thrombin generation in platelet
rich plasma from patients.
AB - Infusion of the GPIIb/IIIa-inhibitor MK383 inhibits thrombin generation in
platelet rich plasma by interfering with the production of platelet procoagulant
phospholipid exposure. The effect is similar to that of 0.2 U/ml of heparin.
Heparin infusion, well known to inhibit thrombin generation by fostering
antithrombin activity, inhibits the formation of platelet-derived procoagulant
microparticles, probably by decreasing the formation of free thrombin, which,
under our circumstances, is the main platelet activator.
PMID- 9759612
TI - A mutation in plasma platelet-activating factor acetylhydrolase (Val279Phe) is a
genetic risk factor for cerebral hemorrhage but not for hypertension.
AB - Platelet-activating factor (PAF) acetylhydrolase is an enzyme that inactivates
PAF. Deficiency of this enzyme is caused by a missense mutation in the gene. We
previously found a higher prevalence of this mutation in patients with ischemic
stroke. This fact suggests that the mutation might enhance the risk for stroke
through its association with hypertension. We have addressed this hypothesis by
analyzing the prevalence of the mutation in hypertension. We studied 138 patients
with essential hypertension, 99 patients with brain hemorrhage, and 270 healthy
controls. Genomic DNA was analyzed for the mutant allele by the polymerase-chain
reaction. The prevalence of the mutation was 29.3% (27.4% heterozygotes and 1.9%
homozygotes) in controls and 36.2% in hypertensives and the difference was not
significant. The prevalence in patients with brain hemorrhage was significantly
higher than the control: 32.6% heterozygotes and 6.1% homozygotes (p <0.05). PAF
acetylhydrolase deficiency may be a genetic risk factor for vascular diseases.
PMID- 9759613
TI - The molecular basis of antithrombin deficiency in Belgian and Dutch families.
AB - The molecular basis of hereditary antithrombin (AT) deficiency has been
investigated in ten Belgian and three Dutch unrelated kindreds. Eleven of these
families had a quantitative or type I AT deficiency, with a history of major
venous thromboembolic events in different affected members. In the other two
families a qualitative or type II AT deficiency was occasionally diagnosed. DNA
studies of the AT gene were performed, using polymerase chain reaction single
strand conformation polymorphism (PCR-SSCP) analysis, followed by direct
sequencing of the seven exons and intron-exon junction regions. Six novel point
mutations were identified: four missense, one nonsense mutation and a single
nucleotide deletion near the reactive site, causing a frameshift with premature
translation termination. In two kindreds the underlying genetic defect was caused
by a whole gene deletion, known as a rare cause of AT deficiency. In these cases,
Southern blot and polymorphism analysis of different parts of the AT gene proved
useful for diagnosis. In another kindred a partial gene deletion spanning 698
basepairs could precisely be determined to a part of intron 3B and exon 4. In two
type I and in both type II AT deficient families a previously reported mutation
was identified. In all cases, the affected individuals were heterozygous for the
genetic defect.
PMID- 9759614
TI - Hemostatic effects of oral contraceptives in women who developed deep-vein
thrombosis while using oral contraceptives.
AB - OBJECTIVE: Comparison of the effect of oral contraceptives on hemostatic
variables in venous thrombosis patients (thrombosis while using oral
contraceptives) with the effect in healthy control subjects. Our aim was to
assess whether some of these effects were more pronounced in women who had
suffered thrombosis, i.e., whether these were "hemostatic hyperresponders". STUDY
DESIGN: A population-based case-control study, the Leiden Thrombophilia Study.
MATERIALS AND METHODS: We investigated 99 pre-menopausal women, age 15-49 years,
who had used oral contraceptives at the time of a first, objectively confirmed
episode of deep-vein thrombosis. They were not pregnant, nor in puerperium, nor
had had a recent miscarriage, and were not using injectable progestogens, nor
suffering from inherited coagulation defects. The median time between occurrence
of deep-vein thrombosis and venepuncture was 18 months, and 30 of the 99 women
were still using oral contraceptives, while 69 had discontinued oral
contraceptive use. In addition, a group of 153 control women (54 of them were
oral contraceptive users and 99 were non-users) were studied. The following
hemostatic variables were measured: APTT, factor VII, factor VIII, factor XII,
fibrinogen, prothrombin, total antithrombin, normalised activated protein C
sensitivity ratio (n-APC-sr), protein C, protein S and free protein S. RESULTS:
We found marked and significant effects of oral contraceptive use on the levels
of several clotting factors, with an increase in factor VII, factor XII, protein
C and a decrease in antithrombin, n-APC-sr and protein S. Less marked effects
that were non-significant or only significant in either patients or controls,
were an increase in factor VIII, fibrinogen and prothrombin and a decrease in the
APTT and free protein S. In the former thrombosis patients several of these
effects of oral contraceptives were more pronounced than in healthy women:
specifically on factor VII, antithrombin, n-APC-sr and protein C. CONCLUSIONS:
Our results of the effects of oral contraceptives generally confirm previous
reports in healthy volunteers. Our data also show that in former deep-vein
thrombosis patients these effects are more pronounced. Apparently some women
become "high hemostatic responders" when exposed to oral contraceptives, and they
may be the women most vulnerable to its thrombogenic effects.
PMID- 9759616
TI - Heterogeneity and immunochemical properties of anti-beta2-glycoprotein I
autoantibodies.
AB - Most anticardiolipin antibodies (ACA) associated with antiphospholipid syndrome
(APS) are directed against epitopes expressed on beta2-glycoprotein I (beta2GPI).
Despite a good correlation between standard ACA assays and those using purified
human beta2GPI as the sole antigen, some sera from APS patients only react in the
latter. This is indicative of heterogeneity in anti-beta2GPI antibodies. To
characterize their reactivity profiles, human and bovine beta2GPI were
immobilized on gamma-irradiated plates (beta2GPI-ELISA), plain polystyrene
precoated with increasing cardiolipin concentrations (CL/beta2GPI-ELISA), and
affinity columns. Fluid-phase inhibition experiments were also carried out with
both proteins. Of 56 selected sera, restricted recognition of bovine or human
beta2GPI occurred respectively in 10/29 IgA-positive and 9/22 IgM-positive
samples, and most of the latter (8/9) were missed by the standard ACA assay, as
expected from a previous study. Based on species specificity and ACA results, IgG
positive samples (53/56) were categorized into three groups: antibodies reactive
to bovine beta2GPI only (group I) or to bovine and human beta2GPI, group II being
ACA-negative, and group III being ACA-positive. The most important group, group
III (n = 33) was characterized by (i) binding when beta2GPI was immobilized on
gamma-irradiated polystyrene or cardiolipin at sufficient concentration
(regardless of beta2GPI density, as assessed using 125I-beta2GPI); (ii) and low
avidity binding to fluid-phase beta2GPI (Kd in the range 10(-5) M). In contrast,
all six group II samples showed (i) ability to bind human and bovine beta2GPI
immobilized on non-irradiated plates; (ii) concentration-dependent blockade of
binding by cardiolipin, suggesting epitope location in the vicinity of the
phospholipid binding site on native beta2GPI; (iii) and relative avidities
approximately 100-fold higher than in group III. Group I patients were
heterogeneous with respect to CL/beta2GPI-ELISA and ACA results (6/14 scored
negative), possibly reflecting antibody differences in terms of avidity and
epitope specificity. Affinity fractionation of 23 sera showed the existence, in
individual patients, of various combinations of antibody subsets solely reactive
to human or bovine beta2GPI, together with cross-species reactive subsets present
in all samples with dual reactivity namely groups III and II, although the latter
antibodies were poorly purified on either column. Therefore, the mode of
presentation of beta2GPI greatly influences its recognition by anti-beta2GPI
antibodies with marked inter-individual heterogeneity, in relation to ACA
quantitation and, possibly, disease presentation and pathogenesis.
PMID- 9759615
TI - Effect of cilostazol on soluble adhesion molecules and platelet-derived
microparticles in patients with diabetes.
AB - We evaluated the plasma concentrations of soluble adhesion molecules and platelet
derived microparticles (PMP) in patients with non-insulin dependent diabetes
mellitus (NIDDM) and studied the effect of cilostazol on PMP generation. There
were differences in the levels of soluble adhesion molecules between NIDDM
patients (N = 43) and the control subjects (N = 30) (soluble thrombomodulin:
11.5+/-5.3 vs. 7.0+/-1.2 TU/ml, p<0.0001; soluble vascular cell adhesion molecule
1: 708+/-203 vs. 492+/-113 ng/dl, p<0.0001; soluble intercellular cell adhesion
molecules- 1: 274+/-65 vs. 206+/-48 ng/dl, p<0.0001; soluble P-selectin: 194+/-85
vs. 125+/-43 ng/dl, p<0.0001). There were also differences in the levels of PMP
and platelet activation markers between NIDDM patients and the controls (PMP:
943+/-504 vs. 488+/-219/10(4) plt, p<0.0001; platelet CD62P: 9.2+/-4.6 vs. 4.4+/
4.3%, p<0.001; platelet CD63: 10.2+/-4.5 vs. 4.5+/-3.3%, p<0.0001; platelet
annexin V: 9.1+/-3.9 vs. 5.3+/-3.8%, p<0.001). To study the release of PMP into
plasma, a modified cone-and-plate viscometer was used. Increased release of PMP
from platelets was observed in diabetic plasma compared to normal plasma under
high shear stress conditions (2,672+/-645 vs. 1,498+/-386/10(4) plt, p<0.05).
Therefore, one cause of PMP elevation in NIDDM may be high shear stress. The
levels of PMP, activated platelets, and soluble adhesion molecules all decreased
significantly after treatment with cilostazol. These results suggest that
cilostazol may be useful for the inhibition of both PMP-dependent and
independent vascular damage in NIDDM.
PMID- 9759617
TI - Thromboembolic complications associated with the use of prothrombin complex and
factor IX concentrates.
AB - In 1994, shortly after a heat-treated prothrombin complex concentrate (PCC) had
been withdrawn from the German market due to transmission of hepatitis B, the
license of another brand was withdrawn, due to 3 acute fatalities associated with
the use of this product. We report on the clinical data of altogether 5 patients,
who died during a 3 month period in Germany after having received this brand of
PCC. All patients had surgery, acquired deficiencies of coagulation factors, and
underlying diseases predisposing for thrombosis or disseminated intravascular
coagulation. PCC was administered for the prevention of bleeding. In three
patients, a drug interaction of PCC with aprotinin may also have played a role.
Several points, however, are suspicious of a major causative effect of the
respective product, (a) the close temporal correlation between administration of
the drug and the subsequent clinical as well as laboratory deterioration, (b) the
accumulation of these adverse events in a short period of time, when the use and
market share of this brand increased due to the shortage of other products, and
(c) laboratory abnormalities of this brand which have been consistently observed
in several in vitro studies.
PMID- 9759618
TI - Molecular bases of pseudo-homozygous APC resistance: the compound heterozygosity
for FV R506Q and a FV null mutation results in the exclusive presence of FV
Leiden molecules in plasma.
AB - Pseudo-homozygous APC resistance, the condition resulting from compound
heterozygosity for FV R506Q (FV Leiden) and quantitative FV deficiency, provides
a natural model to study the interaction between procoagulant and anticoagulant
defects. This paper reports a complete FV characterization of a pseudo-homozygous
APC resistant thrombotic patient. The expression of the patient's non-Leiden gene
was found to be severely impaired both at the mRNA and protein levels. In
particular, only FV Leiden molecules were detected in the patient's plasma by
immunoblotting, which accounts for the observed marked APC resistance. Analysis
of the FV cDNA obtained by reverse transcription of platelet RNA revealed that
the mRNA of the non-Leiden gene was extremely reduced in amount. A PAC clone
containing the whole FV gene was used to design primers for a complete FV exon
scanning. A 2-bp insertion at nucleotide 3706 in the large exon 13 of the non
Leiden gene, predicting a frame-shift and premature termination of protein
synthesis, was identified as responsible for the FV defect. Failure to find any
case of pseudo-homozygous APC resistance in a large sample (6,804) of blood
donors suggests that this condition is extremely rare among normal controls and
that its detection is favoured by the thrombotic risk that it may confer.
PMID- 9759619
TI - Prothrombin and its derivatives stimulate motility of melanoma cells.
AB - Several studies indicated that activation of the clotting system may promote the
growth and the invasive behavior of tumor cells. In the present study, we
evaluated the migratory response of various melanoma cell lines to several
clotting factors and prothrombin derivatives (thrombin, fragment 1, fragment 2
and kringle 1 fragment). Prothrombin, thrombin and fragment 1 stimulated
chemotaxis of the murine (K-1735 M2, X21) and human A375 (SM) melanoma cell
lines. Prothrombin and prothrombin fragment 1 showed their maximal chemotactic
activity at 0.5 approximately 1 microM. Chemotaxis induced by thrombin was
inhibited by hirudin, but not that induced by prothrombin or fragment 1. Other
clotting proteins and the fragment 2 and kringle 1 fragment of prothrombin did
not elicit chemotactic activity. Checkerboard analysis indicated that motility
was directional with a significant chemokinetic component. The K-1735 M2 cells
also migrated in a concentration-dependent manner to substratum-bound insoluble
prothrombin, thrombin or fragment 1. Ligand binding assays showed that both
prothrombin and fragment 1 bound to K-1735 M2 cells with apparent Kds of 0.5
microM. This binding was inhibited by an excess concentration of unlabeled
prothrombin and fragment 1 but not by similar concentrations of other prothrombin
fragments. These findings suggest that prothrombin and its fragment 1 exert
chemotactic activity on melanoma cells by different mechanisms and different
binding sites from that induced by thrombin.
PMID- 9759620
TI - The effects of standard and low molecular weight heparin on bone nodule formation
in vitro.
AB - Previously, we demonstrated in a rat model of heparin-induced osteoporosis that
low molecular weight heparin (LMWH) produces less bone loss than unfractionated
heparin, and that only heparin increases osteoclast number and activity. In
contrast, both heparin and LMWH were found to decrease osteoblast function to a
similar extent, possibly because at the doses tested both agents produced maximal
inhibition. To examine the relative effects of heparin and LMWH on osteoblast
function more closely we used an in vitro bone nodule assay, together with
measurements of alkaline phosphatase (ALP) activity. Both agents inhibited bone
nodule formation and ALP activity in a concentration-dependent manner, but 6 to 8
fold higher concentrations of LMWH were required to achieve equivalent effects.
The effect of heparin on osteoblast function was both chain-length and negative
charge-dependent because the ability of defined heparin fragments to inhibit
nodule formation correlated with their molecular weight (r = 0.98), and N
desulfated heparin was less inhibitory than heparin. In contrast, the effect of
heparin on osteoblast function was pentasaccharide-independent because heparin
with low affinity for antithrombin had similar activity to heparin with high
antithrombin activity. These findings help to explain mounting clinical evidence
that the risk of osteoporosis is lower with LMWH than with heparin.
PMID- 9759621
TI - Interaction of the A1 subunit of factor VIIIa and the serine protease domain of
factor X identified by zero-length cross-linking.
AB - We have previously used a solid phase binding assay to localize a Factor X (FX)
interactive site to the acidic C-terminus of the A1 subunit of FVIIIa (Lapan KA,
Fay PJ. J Biol Chem 1997; 272: 2082-2088). The complex of FVIII-FX was made
covalent following reaction with the zero-length cross-linking reagent 1-ethyl-3
(3dimethylaminopropyl-)carbodiimide hydrochloride (EDC). Western blotting of the
thrombin-cleaved complex showed that the Al subunit of FVIIIa associated with FX
heavy chain. The FX-A1 product was also detected following cross-linking to the
A1/A3-C1-C2 dimer, but not the activated protein C-cleaved A1(336)/A3-C1-C2 form,
indicating that a residue(s) in the region spanning Met337-Arg372 contributed to
the intermolecular ion pair(s). A synthetic peptide to this acidic region
(FVIII337-372) cross-linked to FX and the product was alkaline resistant
indicating that amide linkage(s) were formed. Sequence analysis of the FX
FVIII337-372 adduct suggested that the first 12 NH2-terminal residues of the FX
and peptide do not participate in cross-link formation. Conversion of the cross
linked product to FXa by RVV-X showed that the peptide was associated with the
serine protease-forming domain of the heavy chain. These results indicate that
the association of FVIIIa and FX occurs from a salt linkage(s) formed between
residues of the A1 acidic C-terminus of the cofactor (within residues 349-372)
and the serine protease-forming domain of the substrate.
PMID- 9759622
TI - Proteolysis of tissue factor pathway inhibitor (TFPI) by plasmin: effect on TFPI
activity.
AB - An important regulator of the initiation of blood coagulation is the plasma
glycoprotein, tissue factor pathway inhibitor (TFPI). TFPI inhibits factor Xa and
factor VIIa/tissue factor complex, thereby dampens the proteolytic cascade of the
tissue factor pathway. Plasma clot lysis is primarily mediated by the
fibrinolytic enzyme, plasmin, which is generated through limited proteolysis of
plasminogen by endogenous or exogenously administered plasminogen activators. In
this study, the interaction of plasmin with recombinant E. coli-derived TFPI
(rTFPI) was examined. Plasmin was found to cause a time and concentration
dependent proteolysis of rTFPI, resulting in the decrease of anti-factor Xa
(measured by chromogenic substrate assay) and anticoagulant (measured by tissue
factor-induced clotting assay) activities. Amino-terminal sequencing of the
proteolytic fragments revealed that plasmin cleaved rTFPI at K86-T87, R107-G108,
R199-A200, K249-G250, and K256-R257. Western blot analysis showed that
proteolysis of exogenously added rTFPI also occurred in plasma supplemented with
urokinase, and this is accompanied by decrease of anticoagulant activity. These
changes were abolished by addition of aprotinin, an inhibitor of plasmin. These
data indicate that TFPI is susceptible to proteolysis when plasma fibrinolytic
system is activated. The results taken together suggest that plasmin degradation
of TFPI may contribute to rethrombosis after thrombolysis, and may contribute to
the variability of the efficacy of TFPI in various thrombolysis/reocclusion
studies reported previously.
PMID- 9759623
TI - Ristocetin- and thrombin-induced platelet aggregation at physiological shear
rates: differential roles for GPIb and GPIIb-IIIa receptor.
AB - We recently reported that washed platelets (WP) activated with ADP and expressing
surface-bound vWF aggregated in flow through small tubes or in a cylindrical
couette device at physiological shear rates of G = 300 s(-1)-1000 s(-1) in the
absence of exogenous ligands, with GPIb-vWF partially, and activated GPIIb-IIIa
totally required for the aggregation. We have now extended these studies to
aggregation of platelets "activated" with ristocetin or thrombin. Washed platelet
suspensions with added soluble vWF and ristocetin (0.3-0.75 mg/ml), or activated
with thrombin (0.01-0.5 U/ml) but no added ligand, were sheared in a coaxial
cylinder device at uniform shear rate, G = 1000 s(-1). The collision capture
efficiency (alphaG) with which small aggregates form (= experimental/calculated
initial rates of aggregation) was correlated with vWF platelet binding assessed
by flow cytometry. The vWF-GPIb interaction was exclusively able to support
ristocetin-mediated shear aggregation of metabolically active platelets, with
very few vWF monomer equivalents bound per platelet (representing < or = 10
molecules of 10 million Da) required to yield high capture efficiencies (alphaG =
0.38+/-.02; n = 11), suggesting rapid and stable bond formations between vWF and
GPIb. However, platelet surface-expressed vWF, generated by addition of thrombin
to washed platelets, was found to mediate platelet aggregation with alphaG =
0.08+/-.01 (n = 6), surprisingly comparable to that previously reported for WP
and ADP activation. Blocking the GPIIb-Illa receptor decreased alphaG by 95+/-3%
(n =3), while a monoclonal antibody to the vWF site on GPIb caused a 49+/-7% (n =
8) decrease in alphaG. The partial role for GPIb thus appears to reflect a
facilitative function for increasing contact time between flowing platelets, and
allowing engagement of the GPIIb-IIa receptor to yield stable attachment.
PMID- 9759624
TI - A heparin-coated circuit maintains platelet aggregability in response to shear
stress in an in vitro model of cardiopulmonary bypass.
AB - Alterations in platelet aggregability may play a role in the pathogenesis of
qualitative platelet defects associated with cardiopulmonary bypass (CPB). We
circulated fresh heparinized whole blood through tubing sets coated with heparin
(C group, n = 10) and through non-coated sets (N group, n = 10) as a simulated
CPB circuit. Shear stress (108 dyne/cm2)-induced platelet aggregation (hSIPA),
plasma von Willebrand factor (vWF) activity and platelet glycoprotein (GP) Ib
expression were measured, before, during, and after this in vitro set up of
circulation. In the two groups, the extent of hSIPA significantly decreased
during circulation and was partially restored after circulation. Decreases in the
extent of hSIPA were significantly less with use of heparin-coated circuits.
There was an equivalent reduction in plasma vWF activity, in the two groups.
Expression of platelet surface GP Ib decreased significantly during circulation
and recovered after circulation. Reduction of surface GP Ib expression during
circulation was significantly less in the C group than that in the N group.
Decrease in surface GP Ib expression correlated (r = 0.88 in either group) with
the magnitude of hSIPA, in the two groups. The progressive removal of surface GP
Ib was mainly attributed to redistribution of GP Ib from the membrane skeleton
into the cytoskeleton. Our observations suggest that use of heparin-coated
circuits partly blocks the reduction of hSIPA, as a result of a lesser degree of
redistribution of GP Ib.
PMID- 9759625
TI - Platelet associated fibrinogen and ICAM-2 induce firm adhesion of neutrophils
under flow conditions.
AB - Surface-bound platelets support selectin-mediated rolling and beta2-integrin
mediated firm adhesion of neutrophils (PMN) under flow conditions. We examined
which ligands on platelets mediate this firm adhesion. Surface-bound platelets
express ICAM-2 and GPIIbIIIa-bound fibrinogen, which are ligands for LFA-1 and
MAC-1. In a well defined model for vessel wall injury, blood from an
afibrinogenemic patient was perfused over ECM-coated coverslips to obtain
fibrinogen-free platelet surfaces. At high shear rates, PMN-adhesion to
fibrinogen-free platelet surfaces decreased compared to fibrinogen-containing
controls. Under these conditions, firm adhesion and not rolling was blocked
demonstrating the importance of fibrinogen in this process. In addition, MAC-1
and LFA- on PMN and ICAM-2 on platelets played a role in firm adhesion; the
effect of blocking antibodies was most evident at high shear. The effects of
fibrinogen depletion and ICAM-2 blocking were additive. In conclusion, multiple
redundant ligands, like ICAM-2 and fibrinogen, induce firm and shear resistant
PMN adhesion to platelets under flow conditions. Individually these ligands
become critical at higher shear. Blocking of two or more interactions also
interferes with low shear adhesion.
PMID- 9759626
TI - Analysis of platelet glycoprotein Ia (alpha2 integrin) allele frequencies in
three North American populations reveals genetic association between nucleotide
807C/T and amino acid 505 Glu/Lys (HPA-5) dimorphisms.
AB - Glycoprotein Ia (alpha2 integrin) is a subunit of the heterodimeric membrane
complex (GPIa/IIa) that mediates platelet adhesion to collagen. Several
nucleotide sequence variations of GPIa have been described. A nucleotide 1648 G/A
dimorphism that leads to a Glu/Lys substitution at amino acid 505 is responsible
for the human platelet antigen system, HPA-5. Recently, two other linked GPIa
nucleotide dimorphisms involving codons Phe224 and Thr246 were identified: a C/T
substitution at nucleotide 807 and a G/A substitution at nucleotide 873(1). Using
restriction enzyme digestion of amplified GPIa genomic DNA fragments (PCR-RFLP)
to distinguish genotypes, we have determined the allele frequencies of the GPIa
807C/T and Glu/Lys505 dimorphisms in three North American populations, and a
panel of non-human primates. Our results indicate a genetic relationship between
the 807C/T and Glu/Lys505 dimorphisms that leads to an evolutionary model of GPIa
isoforms.
PMID- 9759627
TI - Differences in platelet alpha-granule release between normals and immune
thrombocytopenic patients and between young and old platelets.
AB - The risk of serious bleeding in patients with immune thrombocytopenic purpura
(ITP) appears to be less than in comparably thrombocytopenic patients with
megakaryocytic hypoplasia. It has been proposed that this difference is due to
enhanced hemostatic activity of young platelets, which are increased in the
circulation during ITP. We examined alpha-granule release in reticulated
platelets (RP), which are thought to be the youngest circulating platelets, and
in older non-reticulated platelets (non-RP) in normal human controls and ITP
patients. Normal controls had a mean RP of 7%, compared with 42% in ITP patients.
The mean concentration of thrombin receptor agonist peptide (TRAP) causing 50% of
control RP to express CD62P (EC50) was 0.82+/-0.08 microM (SEM), significantly
higher than the TRAP CD62P EC50 for RP in ITP, 0.57+/-0.06 microM (p = 0.04).
Similarly, the TRAP EC50 for non-RP in controls, 0.84+/-0.09 microM, was
significantly higher than in ITP, 0.56+/-0.07 microM (p = 0.03), suggesting that
all platelets in ITP have an enhanced alpha-granule threshold response to TRAP
compared with controls, while RP and older platelets within each patient group
have similar threshold sensitivities to TRAP. By contrast, high-dose TRAP caused
RP to express twice as much mean and total CD62P as non-RP in both ITP patients
and controls (p <0.05 for both comparisons). We conclude that compared with
controls, all platelets in ITP are primed to undergo alpha-granule release to
TRAP, while in both ITP and controls, the newly circulating, reticulated
platelets have the potential to contribute greater amounts of CD62P surface
ligand compared with older platelets (non-RP) after stimulation. Both the
increased RP% and enhanced platelet response to agonist in ITP may contribute to
maintenance of hemostasis despite thrombocytopenia.
PMID- 9759628
TI - Abnormal tyrosine phosphorylation linked to a defective interaction between ADP
and its receptor on platelets.
AB - ADP, a primary stimulus of platelets, binds to one or more populations of
receptors on the platelet surface. These receptors are linked to discrete
activation pathways. Both G proteins and tyrosine kinases have been implicated in
the cellular responses to this agonist. We have studied a patient with a
congenital abnormality of ADP-induced platelet aggregation in an effort to gain
information on the signalling pathways used by ADP. Immunoblotting with a broadly
reactive rabbit antibody recognizing the GTP-binding domain of G protein alpha
subunits, and with rabbit antibodies specific for Gialpha1-3, and Galpha12 all
showed normal reactivity when tested against the patient's platelets. The
phosphorylation of proteins was studied using an anti-phosphotyrosine MoAb (4G10)
and platelets stimulated in a platelet aggregometer with ADP, a thromboxane A2
mimetic (IBOP), TRAP-14-mer peptide and alpha-thrombin. With normal platelets, a
time-dependent phosphorylation of several bands in the 60 to 130 kDa mol. wt.
range was observed with all agonists. For the patient, minimal aggregation and
little or no phosphorylation of proteins of 80-85 kDa (cortactin), 100-105 kDa
and 125-130 kDa were seen in response to ADP. The aggregation and phosphorylation
responses were slightly modified in the presence of low doses of thrombin but
were normal with high doses. Aggregation and tyrosine phosphorylation were
virtually absent with IBOP, a finding reproduced when normal platelets were
incubated with IBOP and the CP/CPK ADP scavenging system, thereby underlining the
role of ADP in the response to IBOP. Our results show that the ADP receptor
pathway deficient in the patient is linked to a selective tyrosine
phosphorylation response.
PMID- 9759629
TI - SR 121787, a new orally active fibrinogen receptor antagonist.
AB - The aim of this study was to describe the pharmacological properties of SR
121787, a new antiaggregating drug which is metabolized in vivo into SR 121566, a
potent non-peptide antagonist of Gp IIb/IIIa. In vitro, SR 121566 antagonized the
binding of [125I]-fibrinogen (IC50 = 19.8+/-6.3 nM) and of [125I]-L-692,884, an
RGD-containing peptide (IC50 = 291+/-96 nM) to activated human platelets. SR
121566 inhibited the aggregation of human platelets induced by ADP, collagen,
thrombin, arachidonic acid and PAF at concentrations lower than 0.1 microM.
Adhesion of human platelets to adhesive proteins was inhibited by SR 121566 (IC50
= 40.3+/-2.5 nM) only when Gp IIb/IIIa and fibrinogen were involved. No effect
was found with regard to other adhesive proteins and/or other integrins. SR
121787 demonstrated a potent and sustained antiaggregating effect when
administered intravenously to baboons at a dose 50 microg/kg, and eight hours
after the administration of 100 microg/kg, ADP-induced aggregation was still
strongly inhibited (more than 80%). A single oral administration of 2 mg/kg of SR
121787 produced a nearly complete inhibition of platelet aggregation for up to 8
h (ED50 at 8 h = 193+/-20 microg/kg), a significant residual antiaggregating
activity being still observed 24h after the administration. When administered
orally to rabbits, SR 121787 exhibited a potent antiaggregating (ED50 = 2.3+/-0.3
mg/kg) and antithrombotic activity in an arterio-venous shunt thrombosis model
(ED50 = 10.4+/-0.8 mg/kg). After oral and IV administration, SR 121787 was well
tolerated suggesting that SR 121787, the most potent and long lasting orally
active Gp IIb/IIIa antagonist described to date, is a promising antithrombotic
compound.
PMID- 9759630
TI - Induction of endothelial cell adhesion molecules by serum and immunoglobulins G
from a patient with vasculitis and monoclonal gammapathy: potential relevance to
vasculitis.
AB - Interactions between endothelial cell adhesion molecules and their beta2 integrin
adhesive receptors on leukocytes are thought to play a role in the pathogenesis
of inflammatory diseases and probably vasculitis. We describe a case in whom
leukocytoclastic vasculitis was associated to a monoclonal immunoglobulin G2
kappa (IgG2K). During the vasculitic crisis, the patient's serum and the isolated
IgG from this serum induced the expression of E-selectin, VCAM-1 and ICAM-1 at
the HUVEC surface, but not tissue factor activity, whereas normal, control serum
and patient serum at remission were without any effect. A close relationship
between the vasculitis and the serum level of the monoclonal IgG was observed. We
suggest that the monoclonal IgG might induce the vasculitis by increasing the
expression of E-selectin, VCAM-1 and ICAM-1 which facilitate the interaction of
leukocytes with vascular endothelium.
PMID- 9759631
TI - Heparin regulates ICAM-1 expression in human endothelial cells: an example of non
cytokine-mediated endothelial activation.
AB - Activated endothelial cells up-regulate the expression of several molecules on
their plasma membranes, including intercellular adhesion molecule-1 (ICAM-1). The
role of heparin in regulating endothelial cell gene expression is unclear. We
thus have investigated the ability of heparin to regulate ICAM- gene expression
by using flow cytometry and the ribonuclease protection assay with human
umbilical vein and aortic endothelial cells cultured in growth medium
supplemented with 90 [microg/ml heparin (heparin-sufficient, HS) or in growth
medium without added heparin (heparin-deficient, HD). We found that HD medium
increased plasma membrane protein and mRNA for ICAM-1 but not for HLA-DR, even
though both ICAM-1 and HLA-DR protein and mRNA were inducible by gamma interferon
(IFN-gamma). In addition, phorbol ester and IFN-gamma increased the expression of
plasma membrane ICAM-1 or ICAM-1 and HLA-DR, respectively, more in HD medium than
in HS medium. We found that the HD-mediated increase of ICAM- mRNA was reversible
by the addition of heparin, and that the half-life of ICAM-1 mRNA was the same in
both HS- and HD-treated cells. Also, heparin was found to suppress increases in
ICAM-1 mRNA at a concentration as low as 5 microg/ml. These findings indicate
that heparin deficiency induces endothelial activation characterized by increased
ICAM-1, and that such induction is not dependent on cytokines or endotoxin. The
modulation of ICAM-1 expression by heparin appears to occur at the
transcriptional level. Thus, heparin may have a role in regulating endothelial
function by affecting the expression of ICAM-1, thereby impacting upon the trans
endothelial trafficking of leukocytes.
PMID- 9759632
TI - Two repressor elements inhibit expression of the von Willebrand factor gene
promoter in vitro.
AB - A fragment of the human von Willebrand factor (VWF) gene promoter corresponding
to sequences -487 to +247 bp functions as an endothelial specific promoter in
cell culture. We have previously reported that a GATA transcription factor
functions as an activator and an NF1 like protein functions as a repressor of
this promoter fragment. We have now identified a second negative regulatory
element in the VWF promoter that interacts with nuclear factor(s) (designated R)
in both bovine aortic endothelial and smooth muscle cells. Inhibition of either
the NF1 or the R repressor alone is not sufficient to activate the VWF promoter
in smooth muscle cells. The present studies reveal that simultaneous inhibition
of both repressors activates the VWF promoter in smooth muscle cells. The data
support a model of selective derepression to explain the endothelial cell
specific activity of the 487 to +247 fragment of the VWF promoter in vitro.
PMID- 9759633
TI - Quantitative analysis of von Willebrand factor and its propeptide in plasma in
acquired von Willebrand syndrome.
AB - Measurement of the von Willebrand factor (vWF) propeptide, also known as von
Willebrand antigen II, has been suggested to be helpful in the discrimination of
congenital von Willebrand disease type I from type 2 and in assessing the extent
of activation of the endothelium. We performed a quantitative analysis of mature
vWF and its propeptide in plasma in 8 patients with acquired von Willebrand
syndrome (AvWS) and in 20 normal individuals. Mature vWF levels were
significantly lower in AvWS as compared with normal individuals (13.4+/-3.5 vs
35.6+/-3.3 nM, p <0.001). In contrast, propeptide levels were significantly
higher in AvWS (11.4+/-1.1 vs 4.7+/-0.2 nM, p <0.001), probably reflecting a
compensatory increase in vWF synthesis or increased perturbation of the
endothelium in AvWS. After treatment with DDAVP, propeptide and mature vWF levels
rose 5-fold in AvWS, whereas propeptide levels were not altered by the infusion
of a vWF concentrate or treatment with high dose intravenous immunoglobulins,
indicating that plasma propeptide levels are a reliable reflection of vWF
synthesis. Measurement of propeptide levels may provide additional information in
AvWS as to whether decreased levels of mature vWF in the circulation are due to a
decrease in synthesis or due to an accelerated removal of vWF from the
circulation.
PMID- 9759634
TI - Purification and characterization of kaouthiagin, a von Willebrand factor-binding
and -cleaving metalloproteinase from Naha kaouthia cobra venom.
AB - A von Willebrand factor (vWF)-binding and -cleaving metalloproteinase, termed
"kaouthiagin", was purified from the venom of cobra snake Naja kaouthia.
Kaouthiagin is a monomer with a molecular mass of about 46 kDa and 51 kDa under
non-reducing and reducing conditions, respectively, and the N-terminal amino acid
sequence is homologous to high molecular mass snake venom metalloproteinases.
Kaouthiagin bound to vWF in a divalent ion-independent manner, but the reduced
kaouthiagin failed to interact with vWF, suggesting that the protein conformation
maintained by intrachain-disulfide linkages of the molecule is essential for the
binding to vWF. Neither botrocetin nor bitiscetin, vWF-binding modulators from
another snake venom, interfered with the binding between kaouthiagin and vWF, but
a monoclonal antibody VW92-3 specific to the N-terminal region of vWF (residues 1
910) inhibited the binding. Without affecting platelet GPIb/IX and GPIIb/IIIa,
kaouthiagin specifically cleaved vWF between residues Pro-708 and Asp-709 in a
divalent ion-dependent manner to diminish the multimeric structure of vWF in
plasma, resulting in the loss of ristocetin-induced platelet aggregability and
the collagen-binding activity of vWF. These results indicate that kaouthiagin is
a unique metalloproteinase which specifically binds to and cleaves vWF at a
specific site and that it will be a useful tool for functional dissection of vWF.
PMID- 9759635
TI - Fibrin-rich and platelet-rich thrombus formation on neointima: recombinant tissue
factor pathway inhibitor prevents fibrin formation and neointimal development
following repeated balloon injury of rabbit aorta.
AB - Thrombus formation and neointimal growth are the critical events in restenosis
after balloon angioplasty. However, the responses of diseased vessels to injuries
caused by balloon angioplasty have not been well examined. We investigated the
thrombus formation and neointimal development following the balloon injury to the
previously induced neointima in the rabbit aorta and the effects of recombinant
tissue factor pathway inhibitor (rTFPI) on these responses. Rabbit thoracic
aortas were subjected to injury with a Fogarty 4F balloon catheter at 1.75 atm
(first injury), and 4 weeks later the same vessels were subjected to the second
injury with a Swan-Ganz 5F balloon catheter at 1.4 atm (mild-injury group) or 1.8
atm (severe-injury group), and immediately after that a retrograde bolus
injection of rTFPI (100 microg/kg body weight) or saline was performed into the
injured segments via the central tube of the Swan-Ganz catheter. Twenty minutes
after the second injury, the injured surfaces were covered with platelet-rich
thrombi in the mild-injury group and with fibrin-rich thrombi in the severe
injury group. Damaged intimal smooth muscle cells, which were
immunohistochemically positive for tissue factor (TF), were observed beneath the
fibrin-rich thrombi. The neointima 4 weeks after the second injury was
significantly thicker in the severe-injury group than in the mild-injury group.
The bolus infusion of rTFPI markedly inhibited fibrin formation on the injured
surfaces, and significantly reduced the neointimal development in the severe
injury group at 4 weeks after the second injury. These results indicate that TF
dependent coagulation pathway is primarily responsible for fibrin-rich thrombus
formation and may play an important role in neointimal development following the
balloon injury to the rabbit aortic neointima. Additionally the bolus
administration of rTFPI to the injured vessels could prevent mural thrombus
formation and neointimal growth after balloon angioplasty.
PMID- 9759637
TI - Hepatic vein thrombosis in a patient with mutant prothrombin 20210A allele.
PMID- 9759636
TI - The antiaggregating and antithrombotic activity of clopidogrel is potentiated by
aspirin in several experimental models in the rabbit.
AB - It is unknown whether the addition of aspirin might increase both the efficacy
and the potency of clopidogrel, a potent and selective ADP blocker. For that
purpose, the efficacy of clopidogrel (1-20 mg/kg, p.o.) administered orally to
rabbits alone or in combination with aspirin (0.1-10 mg/kg, p.o.) was determined
in several experimental models. A potent synergistic effect of the
clopidogrel/aspirin association was demonstrated with regard to collagen-induced
platelet aggregation measured ex vivo. Similarly, aspirin potentiated the
antithrombotic activity of clopidogrel measured with regard to experimental
thrombosis induced by a silk thread or on stents placed in an arteriovenous
shunt, thrombus formation following electrical stimulation of the rabbit carotid
artery and with regard to 111In-labeled platelet deposition on a stent implanted
in an arteriovenous shunt or on the subendothelium following air drying injury of
the rabbit carotid artery. A similar potentiating effect of aspirin was obtained
with regard to myointimal proliferation (restenosis) in the femoral arteries of
atherosclerotic rabbits which occurred as a consequence of stent placement. The
clopidogrel/aspirin combination showed only additive-type effects on bleeding
time prolongation induced by ear transection in the rabbit, therefore showing
that combined inhibition of cyclooxygenase and ADP's effects provide a marked
enhanced antithrombotic efficacy. Such a combination may provide substantial
protection against platelet aggregation leading to thrombotic occlusion at sites
of endothelial injuries and coronary artery stenosis in humans.
PMID- 9759638
TI - Prevalence of factor V Leiden and methylenetetrahydrofolate reductase C677T
mutations in Azerbaijan.
PMID- 9759639
TI - The mutation C677T in the methylene tetrahydrofolate reductase gene as a risk
factor for myocardial infarction in the Portuguese population.
PMID- 9759641
TI - Prevalence of FXIII V34L in populations with different cardiovascular risk.
PMID- 9759640
TI - Prevalence of FVR506Q and prothrombin 20210A mutations in the Navarrese
population.
PMID- 9759642
TI - Chromosomal arrangement of the murine coagulation factor VII and factor X genes.
PMID- 9759643
TI - Recurrent venous thrombosis despite correction of activated protein C resistance
following orthotopic liver transplantation.
PMID- 9759644
TI - Clinical usefulness of D-dimer tests in excluding pulmonary embolism is highly
dependent upon age.
PMID- 9759645
TI - Inhibitory effect of argatroban on thrombin-induced MAP kinase activation.
PMID- 9759646
TI - No direct effects of Shiga toxin 1 and 2 on the aggregation of human platelets in
vitro.
PMID- 9759647
TI - Fatal danaparoid-sodium induced thrombocytopenia and arterial thromboses.
PMID- 9759648
TI - Altered protein localization in melanocytes from Hermansky-Pudlak syndrome:
support for the role of the HPS gene product in intracellular trafficking.
AB - Patients with Hermansky-Pudlak syndrome (HPS) exhibit moderate to mild
hypopigmentation of the skin, hair, and eyes. To understand the inherent basis
for this reduced pigmentation, pure cultures of melanocytes were derived using
skin biopsies obtained from four patients with HPS. A nucleotide lesion in the
HPS gene was identified in these individuals. Expression of HPS mRNA, parameters
of melanin synthesis, characteristics in ultrastructural morphology, and
expression of melanocyte-specific proteins were assessed in HPS melanocytes. The
patients' cells appeared microscopically hypopigmented, and melanin content
ranged from 0% to 50% of that for normal melanocytes. In cell lysates of HPS
melanocytes, tyrosine hydroxylase activity was within the normal range, but in
intact HPS melanocytes, it was almost half that of normal melanocytes. HPS
melanocytes also appeared refractory to stimulators of melanization, eg, a
combination of isobutyl methylxanthine and cholera toxin (IBMX/CT). HPS
melanocytes contained many morphologically normal melanosomes, mostly Stage II
with a few Stage I or III. After dihydroxyphenylalanine (DOPA) incubation, there
appeared to be an equal number of Stage II and III melanosomes with the addition
of a moderate number of Stage IV melanosomes. A characteristic ultrastructural
feature of most HPS melanocytes was a variety of unusual cellular structures.
These aberrancies include the following: (a) large membrane-bound complexes
containing membranous chambers, unpigmented, and pigmented melanosomes, irregular
deposits of DOPA reaction products, and granular/amorphous material sometimes
resembling the cytoplasm; and (b) DOPA-positive rings delineated on either side
by limiting membranes. The expression of tyrosinase-related protein-1 and
granulophysin, a 40-kd membrane protein originally identified as a component of
platelet-dense bodies that are undetectable in HPS, was assessed by light
microscopy immunofluorescence. For both proteins, HPS melanocytes exhibited a
large granular pattern of expression throughout the cell, which seems to
correlate with the large membrane complexes observed ultrastructurally. These
observations support the hypothesis that the HPS gene product is involved in
organellogenesis. We propose that in the melanocyte, the HPS gene product
regulates in part the trafficking of melanocyte-specific proteins from the trans
Golgi network to preformed premelanosomes.
PMID- 9759649
TI - Cell cycle-related gene abnormalities and product expression in esophageal
carcinoma.
AB - In esophageal carcinoma, individual genetic alterations of cyclins, cyclin
dependent kinase inhibitors, and final effectors of the G1-to-S transition have
been documented. Our aim was to design a comprehensive analysis of the role and
clinical significance of some critical genes, namely cyclin D1, MTS1, and Rb. To
this end, cyclin D1 gene amplification and protein accumulation, Rb gene allelic
loss and protein expression, and MTS1 gene mutation and DNA methylation were
investigated in a series of 74 esophageal carcinomas. Cyclin D1 amplification was
documented in 17 of 55 (31 %) cases, being a feature of squamous cell type (14 of
17 amplified cases). Cyclin D1 accumulation significantly correlated with lymph
node metastasis (p < 0.02), advanced tumor stage (p < 0.05), and a reduced
overall survival rate (p < 0.03). Rb gene loss of heterozygosity occurred in 14
of 39 (36%) informative cases and was associated with an unfavorable survival
rate (p < 0.01). MTS1 gene mutations were detected in 2 adenocarcinomas only;
gene methylation was observed in 17 of 72 cases (24%) without any correlations
with the variables investigated. A direct association between cyclin D1 and Rb
gene accumulation (p < 0.0005) and an inverse one between RB loss of
heterozygosity and MTS1 abnormalities (p < 0.05) emerged from this study. These
results have important clinical implications because both cyclin D1 and Rb gene
deregulation are significantly related to an unfavorable survival rate. In
addition, cyclin D1 amplification is associated with esophageal carcinoma of
squamous cell type, being totally absent in adenocarcinomas (p < 0.01). The
combined evaluation of these genes also demonstrates that molecular abnormalities
of genes belonging to the same pathway are mutually exclusive and unnecessary for
the neoplastic transformation and tumor progression.
PMID- 9759650
TI - Salt-sensitive aortic aneurysm and rupture in hypertensive transgenic mice that
overproduce angiotensin II.
AB - We studied the effect of excessive salt intake on vascular lesion development in
hypertensive transgenic mice that overproduce angiotensin II, ie, Tsukuba
hypertensive mice (THM). At 6 weeks of age, THM and C57BL/6J (controls) were
given either 1% sodium chloride ("salt-loaded") drinking water or tap water for
30 days. Salt-loaded THM, but not controls, suffered frequent thoracic or
abdominal cavity hemorrhage. THM mortality after 7 days of salt loading was 23%;
after 30 days of salt loading, it rose to 67%. Hemorrhaging occurred due to the
development of aortic aneurysm and rupture at the aortic arch and aorta near the
renal arteries. Vascular lesions progressed with structural degeneration of the
aortic media. Electronmicroscopic analysis revealed that intact THM already
exhibited vascular remodeling consisting of vascular smooth muscle cells (VSMCs)
with developed organelles and an increased extracellular matrix. Salt-loaded THM
suffered aggravated vascular hypertrophy and vascular structure destruction by
plasma material invasion, necrosis of VSMCs possessing extremely swollen
cytoplasm and abundant organelles, and interlamellar bleeding, resulting in
aortic aneurysm and eventual rupture. Interestingly, blood pressure levels and
heart rates in salt-loaded THM did not differ significantly from those of
controls; plasma renin activity between drinking regimens was also comparable
between the two groups. Drinking volume and the concentration of atrial
natriuretic peptide (ANP) in plasma, however, were significantly higher in salt
loaded THM than in intact THM. In addition to aneurysm localization, the findings
regarding drinking volume and plasma ANP suggest that aortic aneurysm and rupture
in salt-loaded THM occurred as the result of an unknown mechanical stress, other
than blood pressure, on the aortic wall. High salt ingestion is involved in the
development of thoracic and abdominal aortic aneurysm in the presence of
hypertension in the activated renin-angiotensin system. THM should therefore
serve as a useful animal model for studying the pathogenesis of aortic aneurysm
accompanied by hypertension.
PMID- 9759652
TI - Matrix metalloproteinase-mediated extracellular matrix protein degradation in
human pulmonary emphysema.
AB - The aim of this study was to investigate the extracellular degrading proteolytic
cascade proteins referred to as matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-9,
membrane-type matrix metalloproteinase-1 (MT1-MMP), tissue inhibitors of matrix
metalloproteinase-1 (TIMP-1), TIMP-2, neutrophil elastase, and alpha1-antitrypsin
in human pulmonary emphysema. Localization of MMP-1, MMP-2, MMP-8, MMP-9, MT1
MMP, TIMP-1, and TIMP-2 was verified by immunohistochemical analysis. The results
of our study indicated that the immunoreactivity of MMP-1, MMP-8, MMP-9, and TIMP
1 was absent, whereas MT1-MMP and MMP-2 were mainly observed in pneumocytes,
fibroblasts, and alveolar macrophages. Although MT1-MMP and MMP-2 were observed
both in emphysematous and normal lung tissue, these immunoreactivities were
intense in the emphysematous samples. The presence of MMP-1, MMP-2, MMP-9, TIMP
1, and TIMP-2 was confirmed at mRNA level by reverse transcription-PCR analysis
and enzyme immunoassay (EIA). However, the only statistical difference that was
observed was in MMP-2 and MMP-9 (MMP-2: emphysematous samples, 19.1+/-2.1 versus
control samples, 5.2+/-0.60 microg/g protein, p < 0.05; MMP-9: emphysematous
samples, 18.4+/-5.6 versus control samples, 8.1+/-2.7 microg/g protein, p <
0.05). Results of the neutrophil elastase as analyzed by EIA, and alpha1
antitrypsin levels as detected by laser nephelometric immunoassay, indicated no
statistical difference between the emphysematous and control groups. In addition
to the presence of mRNA levels, the level of MT1-MMP according to immunoblot
analysis increased in the emphysematous samples. Gelatin zymographic analysis
confirmed the presence of both pro and active forms of MMP-2, and the increased
ratio of the active form of MMP-2 in emphysematous samples (25.9%+/-2.0% versus
11.2%+/-3.3%, p < 0.05), indicated in situ activation of MMP-2 by MT1-MMP.
Elastin zymographic analysis showed elastolytic activity by MMP-2 and MMP-9 but
not the reported band of macrophage metalloelastase (MMP-12). The data suggest
that the MT1-MMP/MMP-2/TIMP-2 system plays a significant role in the MMP-mediated
extracellular matrix degradation and tissue remodeling of emphysematous lungs,
and thus may contribute to the weakening of lung parenchyma and lead to the
formation of emphysema.
PMID- 9759651
TI - Molecular analysis of the human laminin alpha3a chain gene (LAMA3a): a strategy
for mutation identification and DNA-based prenatal diagnosis in Herlitz
junctional epidermolysis bullosa.
AB - Mutations in the genes (LAMA3, LAMB3, and LAMC2) encoding the subunit
polypeptides of the cutaneous basement membrane zone protein laminin 5 have been
reported in different forms of junctional epidermolysis bullosa (JEB), an
inherited blistering skin disease. In this study, we present the complete exon
intron organization of the "a" transcript of the laminin alpha3 chain gene,
LAMA3a, which is expressed primarily in the skin. We have performed fine
resolution mapping of this gene on chromosome 18q11.2 using a human-hamster
radiation hybrid panel. We have also developed a mutation-detection strategy
based on the exon-intron structure of LAMA3a. This strategy, based on PCR
amplification of genomic sequences, followed by heteroduplex scanning and
automated nucleotide sequencing, was used for successful mutation screening in a
family with the lethal (Herlitz) type of JEB, and two novel LAMA3 mutations were
identified in the proband. The mutations consisted of a single-base pair deletion
in LAMA3a exon A11 on the paternal allele, designated 1239delC, and a two-base
pair deletion in LAMA3a exon A23 on the maternal allele, designated 2959delGG.
This information was also used for DNA-based prenatal testing in a subsequent
pregnancy in this family. Collectively, these results attest to our expanding
capability to elucidate the genetic basis of various forms of epidermolysis
bullosa using molecular techniques.
PMID- 9759653
TI - Permanent skin replacement using engineered epidermis containing fewer than 5%
syngeneic keratinocytes.
AB - This study was conducted to investigate permanent skin replacement using
heterologous (syngeneic-allogeneic) epidermal substitutes containing fewer than
5% syngeneic keratinocytes. Keratinocytes were isolated from the skin of new-born
Balb/c (B) and C3H/HeN (C) mice and cocultured in different ratios: 20%B-80%C,
10%B-90%C, 5%B-95%C, and 2%B-98%C (and vice versa). After 4 to 5 days, graftable
epidermal substitutes were obtained and transplanted onto adult Balb/c or C3H/HeN
male mice. Recipients always received the heterografts containing the lower
percentage of their own keratinocytes. On Days 15 and 30 postgrafting, all
heterografts showed significant graft take (> 75%) and skin replacement compared
with allografts. Regenerated tissues were well structured and well vascularized.
These tissues contained only syngeneic keratinocytes. These results led us to
question whether this was an active immune situation. Structural analyses
revealed the presence of leukocyte infiltration that was dependent on the
percentage of allogeneic keratinocytes present in the heterologous implant.
However, even with the 2% syngeneic-98% allogeneic implant, infiltration was
lower than with the allograft. Leukocyte phenotyping confirmed the presence of
immune cells infiltrating the heterologous implants and revealed the involvement
of CD8+ and CD4+ lymphocytes in this immune activation. The percentages of these
two cell populations were lower than those obtained with the allografts,
suggesting moderate cellular activation after each heterograft compared with the
allografts. In conclusion, it is possible to generate functional skin even after
2% syngeneic-98% allogeneic heterografts; there was moderate cellular immune
activation compared with the allografts.
PMID- 9759654
TI - Acquired resistance of a mammalian cell line to hypoxia-reoxygenation through
cotransfection of Kir6.2 and SUR1 clones.
AB - Reoxygenation after transient hypoxia is a common clinical condition that often
causes greater tissue damage than persistent hypoxia itself. This warrants the
development of a means to protect cells against hypoxia-reoxygenation injury.
Adenosine triphosphate (ATP)-sensitive K+ (KATP) channels have been proposed to
play an essential role in the mechanisms of endogenous cellular protection. Thus
far, however, KATP channel proteins have not been exploited to generate an injury
resistant cellular phenotype by delivering KATP channel genes into injury-prone
cells. A first step in this direction is the evaluation of the outcome of
transferring genes encoding KATP channels into a KATP channel-deficient cell type
exposed to metabolic stress. Untransfected COS-7 monkey kidney cells, which
natively lack KATP channels, were found to be vulnerable to hypoxia-reoxygenation
injury, which induced cytosolic Ca2+ loading, as measured by digital
epifluorescent imaging. COS-7 cells cotransfected with KATP channel genes, Kir6.2
and SUR1, gained resistance to hypoxia-reoxygenation. This acquired resistance
was abolished by glyburide, the KATP channel antagonist. We have previously shown
that Kir6.2 and SUR1 physically associate to form a functional KATP channel, not
reconstituted by either of the subunits alone. Transfection with individual
channel subunits, Kir6.2 or SUR1, failed to produce resistance to hypoxia
reoxygenation induced Ca2+ loading. This is a first demonstration that transfer
of KATP channel subunits can generate an injury-resistant cellular phenotype. The
findings from this study may, thus, provide a framework for future therapeutic
strategies based on gene delivery of KATP channel subunits in cells and tissues
vulnerable to hypoxia-reoxygenation insults.
PMID- 9759655
TI - Urokinase-dependent angiogenesis in vitro and diacylglycerol production are
blocked by antisense oligonucleotides against the urokinase receptor.
AB - The plasminogen activator system is known to play a crucial role in the
angiogenesis process by modulating the adhesive properties of endothelial cells
to the extracellular matrix and cell-cell interaction. In the present study, we
demonstrated that the urokinase-type plasminogen activator (u-PA) induced
neovascular growth in the avascular rabbit cornea and dose-dependently promoted
growth, chemotaxis, and matrix invasion of cultured endothelial cells.
Interaction between u-PA and its receptor appears to be mandatory for the
angiogenic effect of u-PA because monoclonal antibodies anti-u-PA and anti-u-PA
receptor (u-PAR) blocked the proangiogenic effects of u-PA at the endothelial
cell level. We then assessed the signaling pathway activated in endothelial cells
by u-PA. u-PAR activation by u-PA produced de novo synthesis of diacylglycerol
(DAG) from glucose by a cytochalasin B-inhibitable mechanism, indicating the
involvement of a specific glucose transporter (GLUT). Endothelial cells expressed
GLUT2, whose activation was tyrosine kinase-dependent and protein kinase C (PKC)
independent. The increase of glucose uptake led to DAG production, which resulted
in PKC activation/translocation. Impairment of u-PAR availability by monoclonal
antibodies and by antisense oligonucleotides (aODN) against u-PAR mRNA inhibited
glucose uptake, DAG neosynthesis, and PKC activation, resulting in the blockade
of endothelial cell proliferation, chemotaxis, and chemoinvasion. These data
suggest that u-PAR activation consequent to the binding of u-PA can be regarded
as an "angiogenic switch" and disclose the possibility that an anti-u-PAR aODN
strategy may efficiently target endothelial cell function to control angiogenesis
in vivo.
PMID- 9759656
TI - Identification of a lipocalin in mucosal glands of the human tracheobronchial
tree and its enhanced secretion in cystic fibrosis.
AB - Members of the lipocalin protein family are characterized by their ability to
bind small hydrophobic molecules. Some of them are known to be produced by
various glands and secretory cells. Under certain conditions, these proteins
would be ideally suited for clearance of lipophilic, potentially harmful
substances and might also act as protection factors in airway secretions. We
therefore used RT-PCR analysis with a set of oligonucleotide primers deduced from
conserved regions of lipocalin members to identify specific RNA isolated from
human trachea. With two of these oligonucleotide primers, a positive result was
obtained. Sequencing of the RT-PCR products revealed that the DNA fragments were
identical to the lipocalin 1 (LCN1) encoding cDNA. LCN1 is an unusual lipocalin
member that binds a variety of lipophilic compounds and exhibits cysteine
proteinase inhibitor and antimicrobial activities. The local production and
topographic distribution of LCN1 in the human tracheobronchial tree was then
investigated by immunoperoxidase staining on thin-layer sections using a specific
antiserum. LCN1 was detectable in the acini of serous mucosal glands and
sometimes within the glandular lumen, suggesting excretion of the protein. The
latter finding was tested and verified by Western blot analysis of bronchial
secretions of healthy individuals. Furthermore, the results of SDS-PAGE and
Western blot analysis of bronchial secretions from patients with cystic fibrosis
(CF), which are usually characterized by an increase of airway lipids, suggested
that LCN1 secretion was enhanced. Northern blot analysis of RNA from normal
trachea and RNA isolated from tracheal biopsies of patients with CF indicated
that induced secretion was due to an up-regulated expression of the LCN1 gene.
Thus, our investigations present the first clear evidence that LCN1 is induced in
infection or inflammation and support the idea that this lipocalin functions as a
physiologic protection factor of epithelia in vivo.
PMID- 9759657
TI - Down-regulation of E-cadherin in mouse skin carcinoma cells enhances a migratory
and invasive phenotype linked to matrix metalloproteinase-9 gelatinase
expression.
AB - To assess the role of gelatinases in mouse skin tumor progression and their link
to the expression of E-cadherin (E-CD), the cell-cell adhesion protein, we used
the highly metastatic squamous HaCa4 cell line and several HaCa4-derived clones
obtained by transfection of the mouse E-CD cDNA. Expression of matrix
metalloproteinase-9 (MMP-9) mRNA and protein activity were present in E-CD (-)
HaCa4 and control clones in culture, but they were strongly diminished in E-CD
(+) clones (E24 and E62) at subconfluence. To explore the suppressive effect of
the cell-cell contacts mediated by E-CD on MMP-9 expression, we introduced a
plasmid encoding mouse E-CD antisense cDNA into the E24 cell clone. The
transfectant P1-clones obtained with reduced or absent E-CD expression showed
increased levels of MMP-9 gelatinase, motility in vitro, and metastatic potential
in vivo. Expression of MMP-9 in the various cell clones was also negatively
modulated by cell density, but this effect was much stronger in E-CD (+) cells,
despite the fact that all of the cell clones analyzed maintained the expression
of P-cadherin and made cell-cell contacts at high cell density. Our results
indicate that in this cell system, the E-CD-mediated cell-cell contacts are
involved in the down-regulation of MMP-9 expression. Thus, the loss of E-CD
triggers a migratory and invasive phenotype in mouse squamous carcinoma cells.
PMID- 9759658
TI - Amplification of c-myc, K-sam, and c-met in gastric cancers: detection by
fluorescence in situ hybridization.
AB - Gene amplifications of c-myc, K-sam, and c-met were examined in cancer nuclei
isolated from 154 primary gastric adenocarcinomas by fluorescence in situ
hybridization (FISH) using cosmid probes for 8q24 (c-myc locus) and 7q31 (c-met),
as well as a DNA probe for K-sam synthesized by PCR. The results were compared
with those of Southern blot analysis. Dual-color FISH using gene locus and
chromosome-specific probes detected gene amplifications of c-myc in 24 tumors
(15.5%), c-met in 6 tumors (3.9%), and K-sam in 3 tumors (2.9%). The six tumors
with c-myc amplification had also been found to have amplified c-erbB-2 in our
previous study, and coamplification of c-myc and c-met was found in two other
tumors. This technique also differentiated the amplified genes on the homogeneous
staining region (HSR) and on double minute chromosomes (DMs) in metaphase spreads
and interphase nuclei of cell lines established from poorly differentiated
adenocarcinomas, KATO III, SNU 16, and HSC 39. Examination of FISH images of
these cell lines suggested that the high-level amplifications of c-myc found in
primary tumors occurred mainly on DM in four tumors and on HSR in one, and those
of K-sam occured on DM in two tumors and on HSR in one. No high-level
amplification of c-met was found. These high-level amplifications were also
detected in formalin-fixed, paraffin-embedded tissues from primary gastric tumors
and metastatic lymph nodes, in some of which heterogeneity of gene amplification
was demonstrated within the same tumor. We conclude that FISH is an important
tool for examining the proto-oncogene aberrations in intact cells in solid
tumors.
PMID- 9759659
TI - Alterations in classical cadherins associated with progression in ulcerative and
Crohn's colitis.
AB - Human colitis is a condition associated with a spectrum of altered morphologic
changes and cellular adhesion. The role of cadherins, which are powerful
morphoregulatory cell adhesion molecules, in colitis is provocative and as yet
unknown. Herein, we present results that suggest a strong correlation between the
deregulation of two cadherin molecules, E- and P-cadherins, and the progression
of human colitis. We examined the expression and structural integrity of E- and P
cadherins in inflamed, dysplastic, or neoplastic human ulcerative colitis (UC)
(n=58), human Crohn's colitis (n = 30), and normal tissue (n = 20) to assess
cadherin function in normal and abnormal epithelium. E-cadherin is strongly
expressed in normal colorectal epithelium, whereas in left-sided UC it is either
down-regulated or has a single-base pair mutation in exon 4 resulting in an amino
acid alteration (6 of 58 UC cases). By contrast, P-cadherin is dramatically up
regulated in both Crohn's disease and ulcerative colitis and especially in
dysplastic ulcerative tissue. In vitro transfected SW-480 colorectal cells
containing E-cadherin mutations identical to those in vivo were associated with
increased spontaneous disaggregation compared with cells transfected with wild
type E-cadherin. Based on this evidence, we hypothesize that a small subset of
colorectal cells expressing mutant E-cadherin are associated with widespread
ulceration, whereas those expressing P-cadherin are associated with a rapidly
dividing immature phenotype that includes dysplasia. The differential expression
of mutated and wild-type cadherins examined herein are associated with a broad
spectrum of abnormal epithelial phenotypes, lymphocyte integrin binding, and
resistance to denudation, as is seen in the colitis adenocarcinoma sequence.
PMID- 9759660
TI - Abnormal distribution of the non-Abeta component of Alzheimer's disease amyloid
precursor/alpha-synuclein in Lewy body disease as revealed by proteinase K and
formic acid pretreatment.
AB - The precursor of the non-Abeta component of Alzheimer's disease amyloid (NACP)
(also known as alpha-synuclein) is a presynaptic terminal molecule that
abnormally accumulates in the plaques of Alzheimer's disease (AD) and in the Lewy
bodies (LBs) of Lewy body variant of AD, diffuse Lewy body disease, and
Parkinson's disease. To better understand the distribution of NACP/alpha
synuclein and its fragments in the LB-bearing neurons and neurites, as well as to
clarify the patterns of NACP/alpha-synuclein compartmentalization, we studied
NACP/alpha-synuclein immunoreactivity using antibodies against the C-terminal, N
terminal, and NAC regions after Proteinase K and formic acid treatment in the
cortex of patients with LBs. Furthermore, studies of the subcellular localization
of NACP/alpha-synuclein within LB-bearing neurons were performed by immunogold
electron microscopy. These studies showed that the N-terminal antibody
immunolabeled the LBs and dystrophic neurites with great intensity and, to a
lesser extent, the synapses. In contrast, the C-terminal antibody strongly
labeled the synapses and, to a lesser extent, the LBs and dystrophic neurites.
Whereas Proteinase K treatment enhanced NACP/alpha-synuclein immunoreactivity
with the C-terminal antibody, it diminished the N-terminal NACP/alpha-synuclein
immunoreactivity. Furthermore, formic acid enhanced LB and dystrophic neurite
labeling with both the C- and N-terminal antibodies. In addition, whereas without
pretreatment only slight anti-NAC immunoreactivity was found in the LBs, formic
acid pretreatment revealed an extensive anti-NAC immunostaining of LBs, plaques,
and glial cells. Ultrastructural analysis revealed that NACP/alpha-synuclein
immunoreactivity was diffusely distributed within the amorphous electrodense
material in the LBs and as small clusters in the filaments of LBs and neurites.
These results support the view that aggregated NACP/alpha-synuclein might play an
important role in the pathogenesis of disorders associated with LBs.
PMID- 9759662
TI - Advancing dental research in the 21st century.
PMID- 9759663
TI - The road to pulp biology research: a personal odyssey.
PMID- 9759661
TI - Dendritic mast cells in the human nasal mucosa.
AB - Human mast cells can be divided into two subtypes: MCTC cells, which contain
tryptase and chymase, and MCT cells, which contain tryptase only. Herein we have
used a combination of histamine, tryptase and chymase immunohistochemistry as a
novel approach to the study of mast cells. Using this technique, we have
discovered a new type of MCTC mast cell in biopsies of the nasal mucosa from
healthy subjects and allergic patients. These mast cells have histamine-positive,
dendrite-like cellular processes. Some cells have only one slender process,
whereas other cells have several long processes extending from different parts of
the cell body. Some of the cellular processes divide into two or three terminal
branches, and histamine is sometimes found in small swellings along the course of
the processes. Our findings contribute new aspects to the concept of mast cell
heterogeneity. Thus, human mast cells may vary not only with respect to mediator
content, but also with respect to gross morphologic features such as the presence
of dendrite-like cellular processes. The recognition of this extreme
heterogeneity may be an important step toward a better understanding of mast cell
biology.
PMID- 9759664
TI - Commensal communism and the oral cavity.
AB - The world we live in contains unimaginable numbers of bacteria, and these and
other single-celled creatures represent the major diversity of life on our
planet. During the last decade or so, the complexity and intimacy of the
interactions which occur between bacteria and host eukaryotic cells during the
process of infection have begun to emerge. The study of such interactions is the
subject of the new discipline of cellular microbiology. This intimacy of
bacteria/host interactions creates a major paradox. The average human being is
90% bacteria in terms of cell numbers. These bacteria constitute the commensal or
normal microflora and populate the mucosal surfaces of the oral cavity,
gastrointestinal tract, urogenital tract, and the surface of the skin. In
bacterial infections, much of the pathology is due to the release of a range of
bacterial components (e.g., modulins such as lipopolysaccharide, peptidoglycan,
DNA, molecular chaperones), which induce the synthesis of the local hormone-like
molecules known as pro-inflammatory cytokines. However, such components must also
be constantly released by the vast numbers of bacteria constituting the normal
microflora and, as a consequence, our mucosae should constantly be in a state of
inflammation. This is patently not the case, and a hypothesis is forwarded to
account for this "commensal paradox", namely, that our commensal bacteria and
mucosal surfaces exist in a state of bio-communism, forming a unified "tissue" in
which interactions between bacteria and epithelia are finely balanced to ensure
bacterial survival and prevent the induction of damaging inflammation. Evidence
is emerging that bacteria can produce a variety of proteins which can inhibit the
synthesis/release of inflammatory cytokines. The authors predict that such
proteins are simply one part of an extensive signaling system which occurs
between bacteria and epithelial cells at mucosal surfaces such as those found in
the oral cavity.
PMID- 9759665
TI - The riddle of the large loss in bite force after fast jaw-closing movements.
AB - In unloading experiments (in which the resistance to a forceful static bite is
suddenly removed), it is shown that the residual bite force (when the jaw system
is arrested shortly after the unloading) is remarkably small. For example, of a
100-N initial bite force, only 18 N is left after a jaw travel distance of 5.0
mm. The present experiments were designed to study whether the magnitude of the
low residual bite force is dependent on the initial bite force, the initial
degree of mouth opening, and the distance of jaw travel. Furthermore, we analyzed
whether the low magnitude of the residual force can be attributed to reflex
events of the jaw muscles or to the force-length properties of the jaw-closing
muscles. It was found that the residual forces are largely dependent on the
distance of jaw travel and are barely sensitive to variations in initial mouth
opening. The relative residual forces are independent of the magnitude of the
initial bite force. The maximum residual forces are on the order of 25% of the
initial bite force after a jaw travel of 4.5 mm. The low values of the residual
forces cannot be attributed to reflex events, because it took about 80 ms for the
masseter muscles to decrease their force to a 50% level after their excitation
was switched off. Furthermore, it was shown that the force-length properties of
the jaw-closing muscles are not responsible for the small values of the residual
forces, since over the trajectories used in the present experiments, the
sarcomere lengths of the jaw-closing muscles were beyond their optimum. It is
suggested that the low residual forces are brought about by (1) a non-uniform
sarcomere behavior of the jaw-closing muscles when contracting, or (2) a long
lasting change in the myofilament system of the closing muscles induced by the
sudden shortening of muscle fibers.
PMID- 9759668
TI - Expression of transforming growth factor-beta 1 (TGF-beta1) in the developing
periodontium of rats.
AB - Transforming growth factor-beta 1 (TGF-beta1) has been reported to be expressed
within several tissue compartments of developing molar crowns and therefore is
implicated in tooth development. Additionally, TGF-beta1 may also play a crucial
role in tissue repair and regeneration. The aim of this study was to determine
the distribution of TGF-beta1 in the developing periodontal attachment apparatus
(cementum, periodontal ligament, and alveolar bone) in Lewis rats. Animals aged
3, 6, and 12 wks were killed, their mandibles removed, fixed, demineralized, and
processed in paraffin. The localization of TGF-beta1 in tissues was detected by
polyclonal goat antibodies against human TGF-beta1 by means of immunoperoxidase
techniques. TGF-beta1 messenger RNA was detected by in situ hybridization with a
cocktail oligonucleotide probe. Cell counts were determined for analysis of the
percentage of cells stained positive for TGF-beta1. Results revealed that TGF
beta1 was expressed in the developing alveolar bone, periodontal ligament, and
cementum at all stages of tissue development studied. Staining was stronger at
sites of cementum and alveolar bone compared with the periodontal ligament.
Intensity of the positive staining, based on 3 grades, indicated a similarity
between the tissues obtained from different ages, but varied between several cell
types. Cementoblasts and osteoblasts stained more strongly than fibroblasts.
Large numbers (approximately 90%) of the osteocytes in developing bone expressed
TGF-beta1; however, in mature bone, fewer osteocytes stained for TGF-beta1. The
percentages of positively stained cementoblasts, osteoblasts, and fibroblasts in
the periodontal space were greater at the apical portion than at the cervical
portion of the root. TGF-beta1 mRNA was expressed in osteoblasts, some bone
marrow cells, cementoblasts, and fibroblasts. This study indicates that TGF-beta1
may play an important role in the modulation of tissue formation and development
of the periodontium.
PMID- 9759666
TI - cDNA cloning of S100 calcium-binding proteins from bovine periodontal ligament
and their expression in oral tissues.
AB - The periodontal ligament (PDL) is a unique tissue that is crucial for tooth
function. However, little is known of the molecular mechanisms controlling PDL
function. To characterize PDL cells at the molecular level, we constructed a cDNA
library from bovine PDL tissue. We then focused on the isolation of S100 calcium
binding proteins (CaBPs), because they mediate Ca2+ signaling and control
important cellular processes such as differentiation and metabolism. We screened
the PDL cDNA library with a mouse S100A4 cDNA, and cloned the bovine cDNAs of two
S100 CaBPs (S100A4 and S100A2). In northern blotting analysis, the highest
expression of S100A4 was detected in PDL from erupted teeth (PDLE). PDL from
teeth under eruption (PDLU) showed a lower expression of S100A4, and its
expression in gingiva was faintly detectable. S100A4 expression was also high in
the pulp tissue followed by the dental papilla of the tooth germ. S100A2
expression was high in PDLE and gingiva. Interestingly, only PDLE exhibited a
high expression of both S100A4 and S100A2. PDLE also expressed the highest level
of beta-actin, a target cytoskeletal protein for S100A4. It is conceivable that
the high expression of S100A4 in PDLE is a result of the maturation of the PDL
and/or a response to mechanical stress generated by mastication. Since there was
a marked difference of S100A4 expression between PDL and gingiva, we propose that
S100A4 could be a useful marker for distinguishing cells from these two tissues.
PMID- 9759667
TI - Serum or growth factor deprivation induces the expression of alkaline phosphatase
in human gingival fibroblasts.
AB - We have previously reported that the increased expression of alkaline phosphatase
(ALP) activity is a phenotypic characteristic of gingival fibroblasts present in
chronic inflammatory periodontal lesions. We hypothesized that ALP might be
induced in gingival fibroblasts by environmental factors. In the present study,
we investigated the factors influencing the induction of ALP expression in
fibroblasts derived from healthy human gingiva. The withdrawal of serum from
confluent cultures of fibroblasts increased the number of cells positive for ALP
activity and protein, without their proliferation. Suramin, a growth factor
antagonist, induced ALP expression in cells cultured with serum. Serum re
addition or exposure to platelet-derived growth factor-AB and/or insulin-like
growth factor I suppressed ALP induction and caused cell growth. ALP-positive
cells could survive for up to 6 weeks after serum deprivation, a condition
inducing cell death via apoptosis. These results demonstrate that serum or growth
factor deprivation induces the expression of ALP in gingival fibroblasts. ALP
expression is negatively correlated with cell growth and accompanied by a change
into serum-growth-factor-independent survival.
PMID- 9759669
TI - Morphometric studies of collagen and fibrin lattices contracted by human gingival
fibroblasts; comparison with dermal fibroblasts.
AB - Cell shape variations and substratum re-organization during contraction of
floating collagen and fibrin lattices seeded with human gingival fibroblasts were
determined by computerized image analysis of light and scanning electron
microscopic images. Data were compared with those obtained with lattices
populated with human dermal fibroblasts. The extent of collagen lattice
contraction was similar with both cell types, resulting in a two-fold decrease in
the area fractions occupied by collagen fibers. Fibroblasts exhibited a rounded
shape (form factors equal to 0.8 and 0.7 for gingival and dermal cells,
respectively) at day 1 of culture; they possessed a more elongated appearance
(with form factors equal to 0.3 and 0.15 for gingival and dermal cells,
respectively) at day 7. Continuous (gingival) and discontinuous (dermal) layers
of cells were evidenced at the cortex of lattices. Contractions were associated
with a significant reduction of the diameters of collagen fibers. Re-organization
of substratum, as analyzed by the "Rose of Directions" technique, was evidenced
only at the vicinity of filopodia where fibers ran parallel to these protrusions.
Several lysed matrix cavities were observed when fibrin lattices were populated
with gingival but not dermal fibroblasts at day 5 of culture. Although cells in
fibrin lattices exhibited morphometric parameters comparable with those in
collagen lattices, no fibroblast layers could be demonstrated at gel peripheries.
Fibrin matrices consisted of an isotropic network of entangled fibrin filaments
from the start of culture, and only a slight reduction of the diameters of fibrin
fibers could be evidenced in dermal fibroblast-populated lattices. Fibrinolysis
at the vicinity of gingival fibroblasts led to an entire re-organization of
substratum toward the formation of larger fibers. The differential behavior of
gingival vs. dermal fibroblasts inside fibrin but not collagen matrices could
therefore partly explain the increased rate of remodeling of gingiva as compared
with dermis.
PMID- 9759670
TI - Relationship between growth and the pattern of tooth initiation in alligator
embryos.
AB - The temporal and spatial patterns in which teeth are initiated in the growing
jaws of embryos are constant for a species but different for different species.
The sources of the patterns have been explained in two ways. First, they are the
outcome of reactions between molecules created at stationary targets and those
which diffuse through embryonic tissues (e.g., Edmund, 1960). Second, Osborn
(1978) supposed that the patterns mirror the way a (mixed) population of parent
cells, the tooth clone, grows. Westergaard and Ferguson (1986, 1987, 1990)
concluded, from their observations of the sequence of tooth initiation in
alligators, that the complicated sequences in which 20 teeth are initiated in
each tooth quadrant could not be explained by jaw growth. The present study
attempts to refute this criticism by means of measurements made from the raw data
published by Westergaard and Ferguson. These data reveal that new teeth, here
called primary teeth, are added at a constant rate at the back of the jaw.
Interstitial growth of the cells between primary teeth creates space for
secondary teeth in secondary regions. The secondary regions increase in length
exponentially with time. The sequence in which teeth are initiated in the growing
secondary regions was found to be the same in every part of the upper and lower
jaws. It was accurately reproduced by a computer program based on a linear
contraction rate of inhibitory zones and exponential growth of secondary regions.
The results suggest that the posterior progress zone in alligator embryos grows
about 125 microm a day. Newly initiated tooth germs are surrounded by an
inhibitory zone about 250 microm in diameter. These zones contract from 20 to 30
microm a day until they are about 170 microm in diameter. The sequences in which
tooth positions are initiated in embryos may be more the result of the pattern in
which cells escape from molecules that inhibit induction rather than the pattern
in which cells create molecules that initiate induction.
PMID- 9759671
TI - The association between water-borne fluoride and bone mineral density in older
adults.
AB - While the benefit of fluoridation in the prevention of dental caries has been
overwhelmingly substantiated, the effect of fluoride on bone mineral density is
less clear. This cross-sectional study was designed to compare the bone mineral
densities of older adults exposed to various levels of fluoride from community
water systems. Participants were recruited from 3 rural communities with
naturally occurring fluoride in their water systems at 0.03, 0.7, and 2.5 mg/L.
All adults, age 60 and over, were eligible if they were ambulatory and had a long
term history (> or = 20 yrs) of ingesting city water. Bone mineral density (BMD)
was measured by means of dual-energy x-ray absorptiometry at 3 anatomical sites:
lumbar spine, proximal femur, and forearm. A total of 353 white non-Hispanic
women and 317 white non-Hispanic men took part in the study. When the data were
stratified by city of residence and gender, men and women living in the community
with high levels of fluoride in their community water system had significantly
higher lumbar spine BMD than their counterparts from the communities with low and
moderate fluoride levels. The women in the high-fluoride community had
significantly higher proximal femur BMD, but there were no statistically
significant differences among men in either proximal femur or forearm BMD. Long
term exposure (> or = 20 yrs) to higher levels of fluoride appears to have a
positive impact on lumbar spine and proximal femur BMD. Based on the results of
this study, exposure to fluoride at levels considered "optimal" for the
prevention of dental caries (from 0.7 to 1.2 mg/L) appears to have no significant
impact on bone mineral density. The relationship between higher levels of
fluoride exposure and bone mineral density requires further investigation.
PMID- 9759672
TI - Interfacial characteristics of resin-modified glass-ionomer materials: a study on
fluid permeability using confocal fluorescence microscopy.
AB - The tooth interface with resin-modified glass-ionomer cements (RM GICs) is poorly
understood. This study examined the interface, especially with dentin. Cervical
cavities in extracted teeth were restored with Fuji II LC, Vitremer, Photac-Fil,
or a conventional GIC, Fuji Cap II. Fluorescent dye was placed in the pulp
chambers for 3 hrs before the specimens were sectioned. Examination of the
tooth/material interface with a confocal microscope showed that dye uptake by the
restoration varied among materials. A "structureless", non-particulate, highly
stained layer of GIC was observed next to dentin in Fuji II LC. This layer varied
in width, was prominent where the dentin tubules were cut "end-on" and in areas
closer to the pulp, and was not seen adjacent to enamel. Vitremer showed minimal
dye uptake, and the "structureless" layer was barely discernible. Photac-Fil
showed more uniform uptake and absence of this layer. Cracking of enamel was also
noted with these materials. The conventional GIC did not show any dye uptake,
presence of a "structureless" layer, or enamel cracking. We elucidated the
potential mechanisms involved in the formation of a "structureless" interfacial
layer in Fuji II LC by studying the variables of cavity design, surface pre
treatment, water content of the tooth, time for it to develop, early finishing,
and coating of the restoration. This layer, the "absorption layer", is probably
related to water flux within the maturing cement, depending on environmental
moisture changes and communication with the pulp in a wet tooth. The
"micropermeability model" was useful in this study of the interfacial
characteristics of RM GICs.
PMID- 9759673
TI - The relationship of pregnancy, hormones, and melanoma.
AB - There has been considerable interest in the relationship of pregnancy and
melanoma. Since 1951, a number of case reports have suggested that pregnancy may
induce or exacerbate melanoma. Likewise, there has been concern over the
relationship between exposure to oral contraceptives (OCs) or hormone replacement
therapy (HRT) and possible increased risk of melanoma. We critically reviewed:
(1) controlled clinical trials to assess the effect of pregnancy on the prognosis
of melanoma; and (2) epidemiological data to evaluate the risk of melanoma after
exposure to OCs or HRT. Pregnancy before, during, or after the diagnosis of
melanoma does not appear to influence 5-year survival rates. Exposure to OCs or
HRT does not appear to increase the risk of melanoma.
PMID- 9759674
TI - Dermatoses of pregnancy.
AB - Several reported dermatoses of pregnancy have not survived the scrutiny of time
and thus including them in current classification schemes does not serve any
useful purpose. This review resolves issues in the existing conflicting
literature.
PMID- 9759676
TI - Vulvodynia and its differential diagnoses.
AB - Vulvodynia is the symptom of chronic vulvar discomfort characterized by the
patient's complaint of burning and sometimes stinging or rawness. It is a
multifactorial problem in which no single etiologic factor or pathogenetic
mechanism has been identified. Patients with vulvodynia exhibit several features
of neuropathic pain, such as allodynia, hyperalgesia, dysesthesia, and chronic
pain in the absence of ongoing noxious stimuli. The treatment of vulvodynia has,
in the past, focused on irradicating suspected infective causes, such as human
papillomavirus, with varying success. More recently, approaches mimicking the
therapy of other chronic pain syndromes, eg, the use of low-dose antidepressants,
has met with some success. There is a need for uniformity in terminology and
therapeutic approach, epidemiologic studies, and controlled trials to advance our
management of this problem.
PMID- 9759675
TI - Vulvar dermatoses: lichen sclerosus, lichen planus, and vulval dermatitis/lichen
simplex chronicus.
AB - In our vulvar specialty clinic at Oxford Radcliffe Hospital (Oxford, UK),
dermatoses are frequently seen. A recent survey of new patients showed that
lichen sclerosus was the most commonly diagnosed vulvar dermatosis; approximately
one third of the women had this disorder. Vulvar dermatitis was observed in 20%
to 25% of new patients, but lichen planus was rare. Differences were observed in
treatment outcomes for patients with vulvar dermatoses, such as lichen sclerosus
and lichen planus, versus those with dermatologic disorders affecting the vulva,
such as psoriasis and eczema.
PMID- 9759677
TI - Benign vulvar tumors.
AB - Benign tumors of the vulva, although relatively uncommon, are often referred to
dermatologists for evaluation and treatment. The clinical features of benign
tumors may overlap with malignant neoplasms, and therefore, a biopsy is often
necessary to make a definitive diagnosis. This article discusses benign tumors of
the vulva that are not associated with infectious agents and presents their
classification according to cell of origin.
PMID- 9759678
TI - Vulvar intraepithelial neoplasia and carcinoma.
AB - This report describes the classification, clinical profile, etiology, and
management of high-grade squamous vulvar intraepithelial-neoplasia (VIN). Recent
studies have better defined the progressive potential of high-grade VIN and the
relationship of such lesions to squamous vulvar carcinoma. The histologic
classification and descriptions have undergone significant refinement over the
past decade. The increasing use of more conservative therapeutic approaches to
high-grade VIN has demanded greater expertise in clinical evaluation to ensure
invasive disease is not missed or undertreated.
PMID- 9759679
TI - Clinical approach to scleroderma.
AB - Systemic sclerosis (SSc) is a heterogenous disease with a morbidity and mortality
that varies widely. Nonetheless, the future clinical course of an individual
patient can be estimated based on the severity of skin and internal organ
involvement within the first several years of the disease. Patients with limited
cutaneous SSc (ISSc) have skin thickening below the elbows or knees and may have
face and neck involvement. Patients with this subtype of SSc have Raynaud's
phenomenon, digital ulcers, and esophageal dysfunction. Significant morbidity and
mortality arises in those patients with ISSc who develop interstitial lung
disease or pulmonary artery hypertension. Patients with diffuse cutaneous SSc
(dSSc) have skin thickening above the elbows and knees or on the trunk. These
patients have a more abrupt onset of disease, often with constitutional symptoms
and arthalgias. Severe heart, lung, gut, and renal involvement, if it occurs,
tends to develop within the first 5 years of disease, especially within the first
several years. Patients with significant internal organ involvement have a poorer
prognosis than patients who do not. The goals of the initial history and physical
and laboratory examinations are to classify the type of scleroderma as ISSc or
dSSc, to estimate disease duration, and to define the extent and severity of
organ involvement. Treatment of SSc is organ based. Treatment may reduce
morbidity associated with Raynaud's phenomenon, digital ulcers, esophageal
dysmotility, esophageal reflux, gut dysmotility, arthralgias, myositis, and
pulmonary artery hypertension. Therapy may stabilize lung function in patients
with interstitial lung disease with alveolitis and stabilize renal function in
patients with renal crisis. The overall prognosis for patients with SSc appears
to be improving. Patients with early dSSc should be considered for enrollment
onto protocol testing of potential disease-modifying therapies.
PMID- 9759680
TI - Dermatologic lupus: Hopkins Lupus Cohort.
AB - Dermatologic manifestations are among the most common signs of systemic lupus
erythematosus (SLE). The Hopkins Lupus Cohort study is a prospective study in
which patients with SLE are seen on a quarterly basis for measurement of disease
activity, laboratory tests, and assessment of morbidity and quality of life. This
cohort has allowed unique insights into the epidemiologic factors of SLE, the
presentation of dermatologic lupus, and morbidity, all of which are presented in
this report. In addition, the dermatologic signs of antiphospholipid antibody
syndrome (APS) are reviewed. Approaches to treatment of dermatologic lupus and
APS are discussed.
PMID- 9759681
TI - Executive summary of the clinical guidelines on the identification, evaluation,
and treatment of overweight and obesity in adults.
AB - An estimated 97 million adults in the United States are overweight or obese, a
condition that substantially raises their risk of morbidity from hypertension,
dyslipidemia, type 2 diabetes, coronary heart disease, stroke, gallbladder
disease, osteoarthritis, sleep apnea and respiratory problems, and endometrial,
breast, prostate, and colon cancers. Higher body weights are also associated with
increases in all-cause mortality. Obese individuals may also suffer from social
stigmatization and discrimination. As a major contributor to preventive death in
the United States today, overweight and obesity pose a major public health
challenge.
PMID- 9759682
TI - Concepts of fever.
AB - If asked to define fever, most physicians would offer a thermal definition, such
as "fever is a temperature greater than...." In offering their definition, many
would ignore the importance of the anatomic site at which temperature
measurements are taken, as well as the diurnal oscillations that characterize
body temperature. If queried about the history of clinical thermometry, few
physicians could identify the source or explain the pertinacity of the belief
that 98.6 degrees F (37.0 degrees C) has special meaning vis-a-vis normal body
temperature. Fewer still could cite the origin of the thermometer or trace the
evolution of modern concepts of clinical thermometry. Although many would have
some knowledge of the fundamentals of thermoregulation and the role played by
exogenous and endogenous pyrogens in the induction of fever, few would have more
than a superficial knowledge of the broad biological activities of pyrogenic
cytokines or know of the existence of an equally complex and important system of
endogenous cryogens. A distinct minority would appreciate the obvious paradoxes
inherent in an enlarging body of data concerned with the question of fever's
adaptive value. The present review considers many of these issues in the light of
current data.
PMID- 9759683
TI - Calcium antagonists and mortality risk in men and women with hypertension in the
Framingham Heart Study.
AB - BACKGROUND: Several recent studies have suggested that calcium antagonist drugs,
which are widely used for the treatment of hypertension, are associated with
increased risk of cardiovascular disease. These studies have cast doubts on the
long-term safety of calcium antagonists. OBJECTIVE: To examine the association of
calcium antagonist use with mortality in subjects with hypertension followed up
in the Framingham Heart Study. SUBJECTS AND METHODS: We stratified 3539 subjects
(mean+/-SD age, 64+/-13 years) from the Framingham Heart Study who had
hypertension at routine clinic examinations, according to the use of calcium
antagonists and presence of coronary heart disease at the baseline examination.
At each follow-up examination (every 2-4 years), subjects were reclassified with
regard to the use of calcium antagonists. The end point of the study was all
cause mortality. Hazard ratios and 95% confidence intervals associated with the
use of calcium antagonists were obtained using Cox proportional hazards
regression models. RESULTS: There were 970 deaths during follow-up. Hazard ratios
for mortality associated with the use of calcium antagonists were 0.93 (95%
confidence interval, 0.72-1.21; P=.59) for subjects with hypertension without
coronary heart disease, and 0.92 (95% confidence interval, 0.69-1.24; P=.58) for
those with coronary heart disease at baseline. All models were adjusted for age,
sex, current smoking, systolic and diastolic blood pressure, use of beta
blockers, and use of other antihypertensive medications. CONCLUSIONS: In this
cohort of 3539 subjects with hypertension there were no differences in mortality
among subjects with hypertension using a calcium antagonist compared with those
who were not. Results were similar among subjects with hypertension with and
without coronary heart disease. The results of ongoing long-term, randomized
clinical trials will provide more definitive data on the safety of calcium
antagonists.
PMID- 9759684
TI - Renal failure in multiple myeloma: presenting features and predictors of outcome
in 94 patients from a single institution.
AB - BACKGROUND: Twenty percent of patients with multiple myeloma (MM) have renal
failure. OBJECTIVE: To analyze the presenting features, the response to therapy,
and the factors associated with renal function recovery and survival in 94
patients with MM and renal failure. PATIENTS AND METHODS: Medical records of
patients from our institution with MM and renal failure diagnosed between January
1969 and December 1994 were reviewed. The statistical methods consisted of Kaplan
Meier survival curves, the log-rank test, logistic regression analysis, and the
Cox proportional hazards model for survival analysis. RESULTS: Renal failure was
observed in 94 (22.2%) of 423 patients. Patients with renal failure had more
advanced disease than the others. Patients with renal failure had a lower
response rate to chemotherapy than those with normal renal function (39% vs 56%;
P<.001). However, when patients dying within the first 2 months of treatment were
excluded, no significant differences in the response rate were found between
patients with renal failure and those with normal renal function. Renal function
recovery was observed in 26% of patients. Serum creatinine level (<354 micromol/L
[<4 mg/dL]), serum calcium level (> or =2.88 mmol/L [> or = 11.5 mg/dL]), and
amount of proteinuria (< 1 g/24 h) were associated with renal function recovery.
Patients who recovered renal function had a median survival of 28 months vs 4
months for those with nonreversible renal failure (P<.001). In the multivariate
analysis, only serum creatinine level (P=.003) and response to chemotherapy
(P<.001) were correlated with survival. CONCLUSIONS: Renal failure was present in
almost one fourth of patients with MM. Patients with reversible renal failure had
longer survival than those not recovering renal function. When patients dying
within the first 2 months of treatment were excluded, the response rate was not
affected by renal function. Factors associated with renal function recovery were
degree of renal failure, presence of hypercalcemia, and amount of proteinuria.
Response to chemotherapy and severity of renal failure were the only independent
factors associated with survival.
PMID- 9759685
TI - Association of physical activity and human sleep disorders.
AB - BACKGROUND: It is generally believed that exercise exerts a beneficial effect on
the quality of sleep. However, most studies regarding exercise and sleep have
been concerned with the influence of exercise on sleep architecture and
efficiency, and not on its effects in the prevention and treatment of sleep
disorders. Moreover, epidemiological evidence of the benefits of exercise on
sleep are limited. OBJECTIVE: To investigate the influence of moderate exercise
or physical activity on self-reported sleep disorders among a randomly selected
population of adults. SUBJECTS AND METHODS: Study subjects were participants in
the Tucson Epidemiological Study of Obstructive Airways Disease who in the 12th
survey completed health questionnaires that included several questions on
physical exercise and sleep disorders. Sleep disorders were classified as
disorders in maintaining sleep, excessive daily sleepiness, nightmares, and any
sleep disorder. Six questions regarding exercise and physical activity were
asked. Analyses were performed using multivariate logistic regression models with
selected measures of sleep disorders as dependent variables and measures of
exercise and physical activity as the independent or predictor variables.
RESULTS: There were 319 men and 403 women included in the analyses. The results
showed that more women than men reported participating in a regular exercise
program and having sleep symptoms of disorders in maintaining sleep and
nightmares and that more men than women did regular vigorous activity and walking
at a brisk pace for more than 6 blocks per day. Both men and women had
significantly reduced risk of disorders in maintaining sleep associated with
regular activity at least once a week, participating regularly in an exercise
program, and walking at a normal pace for more than 6 blocks per day. Reduced
risk of any sleep disorder was associated with regular activity at least once a
week, and for men, walking at a brisk pace for more than 6 blocks. Among women
increases in age also reduced the risk of nightmares. CONCLUSIONS: These data
provide additional evidence that a program of regular exercise may be a useful
therapeutic modality in the treatment of patients with sleep disorders.
PMID- 9759686
TI - National patterns and predictors of beta-blocker use in patients with coronary
artery disease.
AB - BACKGROUND: Prior studies suggest underuse of beta-blockers in patients with
coronary artery disease, but these studies have been based on selected
populations of recently hospitalized patients. OBJECTIVE: To describe national
patterns and determinants of beta-blocker use in the ambulatory setting. METHODS:
We analyzed 11745 visits by patients with coronary artery disease to randomly
selected, office-based physicians in the National Ambulatory Medical Care Surveys
for 1980, 1981, 1985, and 1989 through 1996. We used multiple logistic regression
to determine the independent effect of sociodemographic and clinical factors on
beta-blocker use. OUTCOME MEASURE: Beta-blocker use at patient visits. RESULTS:
Beta-blocker use was reported in only 20.9% of office visits by patients with
coronary artery disease and no strong contraindications between 1993 and 1996. In
multivariate analyses, age younger than 75 years, residence in the Northeast, and
visits to cardiologists and internists compared with family and general
practitioners predicted greater use of beta-blocker therapy. White race and
private insurance also were significant predictors of beta-blocker use between
1980 and 1996. Longitudinal analyses revealed a significant decline in beta
blocker use from 1980 to 1990, followed by a gradual increase in recent years.
CONCLUSIONS: Beta-blockers appear to be underused in ambulatory patients with
coronary artery disease. Our data suggest that nonclinical factors may influence
rates of use, indicating the need for closer scrutiny of variations in physician
prescribing practices.
PMID- 9759687
TI - Underuse of venous thromboembolism prophylaxis for general surgery patients:
physician practices in the community hospital setting.
AB - BACKGROUND: Venous thromboembolism is a common complication of surgery. Although
surveys of physician self-reported practices have suggested near universal
support for routine use of measures to prevent venous thromboembolism, medical
record auditing has demonstrated underuse. OBJECTIVE: To assess physician
practices of venous thromboembolism prophylaxis in the community hospital
setting. METHODS: Retrospective review of the medical records from 20 hospitals
in Oklahoma of 419 Medicare patients aged 65 years or older undergoing major
abdominothoracic surgery between April 1 and December 31, 1995. Utilization rates
of prophylaxis stratified according to patient risk for venous thromboembolism
were measured. RESULTS: Prophylaxis measures were implemented for only 160 (38%)
of 419 patients studied (95% confidence interval, 33%-43%). There was little
variation in the use of prophylaxis based on the risk for venous thromboembolism.
Only 97 (39%) of 250 patients (95% confidence interval, 33%-45%) at very high
risk received any form of prophylaxis and of these 97, only 64 patients (66%)
received appropriate measures (95% confidence interval, 56%-75%). CONCLUSIONS:
Despite widely disseminated, evidence-based recommendations, venous
thromboembolism prophylaxis is underused in Medicare patients undergoing major
abdominothoracic surgery in community hospitals in Oklahoma.
PMID- 9759688
TI - Factors related to in-hospital deaths in patients with tuberculosis.
AB - BACKGROUND: Deaths from tuberculosis (TB) continue to occur despite the
availability of effective antimicrobial agents. Multidrug resistance, human
immunodeficiency virus (HIV) infection, and delayed therapy have been implicated.
OBJECTIVE: To examine clinical factors associated with in-hospital death in
patients with active TB. METHODS: A retrospective case-control study was
performed on patients admitted to a government hospital in Johannesburg, South
Africa, used as a referral center for patients with TB. Eighty patients admitted
with TB who died during hospitalization were matched with 80 similar patients
with TB who survived hospitalization. Clinical, demographic, and radiological
characteristics of each group were compared. RESULTS: In-hospital fatalities were
associated with female sex (P=.01), lower admission hemoglobin level (P<.01), and
weight (P<.01), and a trend to more extensive infiltrative patterns on chest
radiographs. Multidrug resistance, extrapulmonary disease, and HIV infection were
unexpectedly not related to in-hospital mortality. High mortality in the first
weeks of admission suggested that late presentation was a major factor for in
hospital death. The HIV-infected participants in the study showed less drug
resistance than HIV-negative patients (P=.07), equivalent extents of infiltrative
patterns on chest radiographs, but much less cavitation and fibrosis (P<.01).
CONCLUSIONS: Clinical predictors of early mortality from TB included anemia, low
body weight, and extensive infiltrates, while multidrug resistance and HIV
infection were not significant factors. Previous exposure to TB and delayed
presentation may have influenced our findings. Since patients present late in
their illness, aggressive case finding would be important in controlling TB in
this population.
PMID- 9759689
TI - Trends in infectious disease hospitalizations in the United States, 1980-1994.
AB - BACKGROUND: A recent study concluded that between 1980 and 1992, deaths from
infectious diseases increased 58%. This article explores trends in infectious
diseases as a cause of hospitalization. METHODS: We analyzed data from the
National Hospitalization Discharge Survey for 1980 through 1994 using a
previously developed approach to evaluate infectious diseases in data coded
according to the International Classification of Diseases, Ninth Revision.
RESULTS: Between 1980 and 1994, the rate of hospitalizations in the United States
declined approximately 33%; hospitalizations occurred at a rate of 133+/-5 per
1000 US population (35 million+/-1 million discharges) in 1994. The rate of
hospitalization for infectious diseases declined less steeply--12% during this
interval--resulting in an increased proportion of hospitalizations because of
infectious diseases. In 1994, the rate of hospitalizations for infectious
diseases was 15.4+/-0.7 per 1000 US population (4.0 million+/-0.2 million
discharges). The fatality rate associated with hospitalizations for infectious
diseases increased from 1.9%+/-0.1% to 4.0%+/-0.3%, attributable to increased
hospitalizations of elderly persons and an increased fatality rate among those
younger than 65 years. Among selected categories, hospitalizations for human
immunodeficiency virus infections and acquired immunodeficiency syndrome,
prosthetic device infections, sepsis, and mycosis increased substantially, and
hospitalizations for upper respiratory tract infections, pelvic inflammatory
disease, and oral infections declined sharply. Hospitalizations for lower
respiratory tract infections constituted 37% of all infectious disease
hospitalizations in 1994. CONCLUSIONS: Considering hospitalizations as a
dimension of the burden of infectious diseases involves an array of factors:
secular trends in hospitalization, changing case management practices,
demographic changes, and trends in the variety of infectious diseases themselves.
Increases in the proportions of hospitalizations because of infectious diseases
during years when hospitalizations for all causes were decreasing reflect an
increasing burden of infectious diseases in the United States between 1989 and
the mid-1990s.
PMID- 9759690
TI - Superwarfarin poisoning.
AB - BACKGROUND: Superwarfarin sodium exposure or poisoning is a growing public health
problem. There were 5133 reported cases of superwarfarin exposure and poisoning
in 1988 and 13 423 cases in 1995. Cases may be associated with accidental
exposure, suicide attempts, or Munchausen syndrome, and may be difficult to
diagnose. PATIENTS AND METHODS: Patients from northern Wisconsin with
superwarfarin exposure or poisoning were examined at a tertiary referral center
in rural Wisconsin to determine what led to their exposure and to review the
clinical manifestations, diagnosis, treatment, and prevention of superwarfarin
poisoning. RESULTS: Eleven cases satisfied the criteria for superwarfarin
exposure or poisoning. All 7 children included in the study had accidentally
ingested superwarfarin, 2 adults had Munchausen syndrome, and 1 teenager and 1
adult had attempted suicide using superwarfarin. Nine of the 11 cases had taken
brodifacoum. The patients who had accidentally ingested superwarfarin or
attempted suicide using it were easily diagnosed, while diagnosis was markedly
delayed for the 2 patients with Munchausen syndrome. Full reversal of
anticoagulation was quickly achieved in the cases of accidental ingestion and
attempted suicide. We examined and treated the patients with Munchausen syndrome
for months before establishing a diagnosis and fully reversing the
anticoagulation. None of the patients in our study died of superwarfarin
poisoning. CONCLUSIONS: Superwarfarin exposure or poisoning is a growing public
health problem that should be part of the differential diagnosis of patients who
present with a coagulopathy consistent with vitamin K deficiency in the absence
of coumadin therapy, liver disease, or the use of an inhibitor, and whose
conditions do not resolve with large doses of parenteral vitamin K1 therapy.
PMID- 9759691
TI - Microalbuminuria in nondiabetic adults: relation of blood pressure, body mass
index, plasma cholesterol levels, and smoking: The Gubbio Population Study.
AB - BACKGROUND: Evidence exists that cardiovascular risk factors influence
progression toward end-stage renal failure. We tested the hypothesis that in
nondiabetic middle-aged adults without macroalbuminuria, cardiovascular risk
factors are related to urinary albumin excretion and prevalence of
microalbuminuria, a sign of early nephropathy. METHODS: Cross-sectional analysis
of data for 1567 participants in The Gubbio Population Study (677 men and 890
women), aged 45 to 64 years, without macroalbuminuria, without diabetes mellitus,
and with fasting plasma glucose levels of less than 7.8 mmol/L (140 mg/ dL). Data
collection included albumin and creatinine excretion in timed overnight urine
collection; levels of fasting plasma cholesterol, glucose, triglycerides,
creatinine, and uric acid; creatinine clearance; red blood cell sodium-lithium
countertransport; blood pressure; weight; height; medical history; smoking
status; and alcohol intake. Urinary albumin excretion and prevalence of
microalbuminuria were the dependent variables. RESULTS: Blood pressure, plasma
cholesterol levels, smoking, and body mass index significantly related to urinary
albumin excretion and prevalence of microalbuminuria. In analyses with control
for multiple variables, relative risk for microalbuminuria (urinary albumin
excretion, 20-199 microg/min) in men and women was 2.51 and 1.62, respectively,
with 18 mm Hg higher (1 SD) systolic blood pressure; 2.25 and 2.10, respectively,
with 1.0-mmol/L (40 mg/dL) higher plasma cholesterol level; 1.99 and 1.91,
respectively, for smokers vs nonsmokers; and 1.83 and 1.33, respectively, with 4
kg/m2 higher body mass index. Findings were similar for microalbuminuria defined
as urinary albumin excretion of at least 25 microg/dL glomerular filtration rate.
CONCLUSION: Major cardiovascular risk factors are independent correlates of
microalbuminuria in nondiabetic middle-aged adults.
PMID- 9759692
TI - Hospital-acquired pressure ulcers: risk factors and use of preventive devices.
AB - BACKGROUND: Pressure ulcers are a frequent complication of bed rest. We examined
risk factors for hospital-acquired pressure ulcers, the use of preventive
devices, and the impact of case-mix adjustments on between-ward comparisons.
METHODS: We conducted 3 cross-sectional surveys in a teaching hospital of 2373
patients who had no pressure ulcer on admission. We assessed the presence of
pressure ulcer, dates of admission and ulcer occurrence, hospital ward, patient
age and sex, appetite and route of nutrition, surgery during stay,
hospitalization for fracture, comorbidities, use of low-pressure devices (special
mattresses, cushions, and pressure-reducing beds), and the Norton Pressure Ulcer
Prediction score (physical condition, mental condition, activity, mobility, and
incontinence). RESULTS: Two hundred forty-seven new pressure ulcers occurred (5.7
per 1000 person-days). In multivariate analysis, the risk for pressure ulcer
increased with age (risk gradient across 5 categories was 1:4.5; P<.001) and
Norton score (across 5 categories, risk gradient was 30-fold; P<.001); other risk
factors (all relative risks, 1.5-1.8; P<.002) were hospitalization for fracture,
surgical intervention, reduced appetite, and nasogastric tube or intravenous
nutrition. Adjustment for case mix substantially modified differences between
hospital wards. Use of preventive devices was associated with Norton score, but
not all high-risk patients benefited. CONCLUSIONS: Pressure ulcers were seen in
every 10th hospitalized adult. Patient age and Norton score were the strongest
risk factors for pressure ulcers. Use of preventive devices was suboptimal.
Adjustment for case mix is essential if pressure ulcer incidence is to be used as
an indicator of quality of care.
PMID- 9759693
TI - Ischemic colitis and sumatriptan use.
AB - Sumatriptan succinate, a serotonin-1 (5-hydroxytryptamine-1) receptor agonist, is
an antimigraine drug that is reported to act by selectively constricting
intracranial arteries. Recently, vasopressor responses that are distinct from the
cranial circulation have been demonstrated to occur in the systemic, pulmonary,
and coronary circulations. Cases have been published of coronary vasospasm,
myocardial ischemia, and myocardial infarction occurring after sumatriptan use.
We report on the development of 8 serious cases of ischemic colitis in patients
with migraine treated with sumatriptan.
PMID- 9759694
TI - First-generation vs second-generation antihistamines.
PMID- 9759695
TI - Upper extremity DVT: what is the risk?
PMID- 9759696
TI - Glioblastoma multiforme presenting as asymptomatic hyperprolactinemia.
PMID- 9759697
TI - Dermatology education for internists.
PMID- 9759698
TI - Adherence and effectiveness of highly active antiretroviral therapy.
PMID- 9759699
TI - Combining volume-weighted mean nuclear volume with Gleason score and clinical
stage to predict more reliably disease outcome of patients with prostate cancer.
AB - BACKGROUND: Various criteria for patients with prostate cancer have been reported
to be of prognostic value, and we have reported that estimates of volume-weighted
mean nuclear volume (MNV), developed by Gundersen and Jensen based on a
stereological technique, accurately predict the prognosis of prostate cancer.
However, all of these studies were conducted on cases in a single institution,
and it has remained unclear whether MNV calculations obtained at one institution
apply to cases at another institution. In attempting to solve this problem, we
made a prognostic index (P.I.) based on data from one hospital, and tested
whether these data could be used to predict the prognosis of patients at another
hospital. MATERIALS AND METHODS: A retrospective, multivariate prognostic study
of 195 patients with prostate cancer, diagnosed at Kyoto University Hospital and
treated conservatively, indicated that clinical stage, Gleason score, and MNV
were all significantly correlated with the prognosis of patients with prostate
cancer. From the relative strengths of these prognostic factors in a multivariate
analysis, the following P.I. was constructed: P.I. = Clinical stage x 1.8040 +
Gleason score x 1.5245 + MNV x 2.3162 (the constants correspond to the risk ratio
estimated by Cox analysis). The P.I. was calculated for 104 patients with
prostate cancer diagnosed at Shizuoka City Hospital and treated conservatively
for analysis of disease-specific survival. RESULTS: The prognostic index ranged
from 3.841-16.142. Using the median value of 12.5 as a cutoff point, a clear
separation of cases with poor and favorable prognosis was achieved (P < 0.0001,
observation period: 1-167 months). CONCLUSIONS: The results of this study suggest
that estimates of MNV can be evaluated at multiple institutions with the use of
P.I. calculation. Furthermore, combining estimates of MNV with Gleason score and
clinical stage predicts most powerfully disease outcome of patients with prostate
cancer.
PMID- 9759700
TI - Effect of dual inhibition of 5-alpha-reductase and aromatase on spontaneously
developed canine prostatic hypertrophy.
AB - BACKGROUND: Our aim was to assess the effect of dual inhibition of 5-alpha
reductase and aromatase on prostate glands. METHODS: We investigated the
morphological changes in the prostate gland and the changes in the hormonal
environment after administration of finasteride and arimidex to intact canine
specimens. The study consisted of four groups: a 5-alpha-reductase only group
(5RI only, n = 5); a 5RI plus aromatase-inhibitor combination group (5RI + ARI
combination, n = 5); a BPH control group (n = 3); and a castration control group
(n = 3). Finasteride (1 mg/kg/day) and the same dose of arimidex were orally
administered for 80 days. RESULTS: In the 5RI group, a significant decrease in
the serum dihydrotestosterone (DHT) level was found, and prostatic volume was
significantly decreased. However, significant increases in serum testosterone (T)
and DHT levels were observed, with a concomitant increase in prostatic volume in
the 5RI + ARI combination group. Morphometric analysis showed that
histopathological findings in the 5RI + ARI combination group were similar to
those in the BPH control group. CONCLUSIONS: Dual inhibition of 5-alpha-reductase
and aromatase resulted in a significant increase in prostate volume, accompanied
by a 3-10-fold increase in serum testosterone levels and a significant increase
in testicular volume.
PMID- 9759702
TI - Regressive changes in finasteride-treated human hyperplastic prostates correlate
with an upregulation of TGF-beta receptor expression.
AB - BACKGROUND: Prostatic atrophy has been documented histologically as a consequence
of finasteride action on human hyperplastic prostates. An increase in apoptotic
rates has also been reported in androgen-deprived hyperplastic prostates.
Transforming growth factor beta (TGF-beta) signaling is implicated in apoptotic
cell death. TGF-betas have been detected in normal and diseased human prostate.
In the normal prostate, TGF-beta acts as a predominantly negative growth
regulator. TGF-beta signaling receptors TbetaRI and TbetaRII have been shown to
be negatively regulated by androgens. METHODS: We studied the histological
changes in 9 selected finasteride-treated patients with benign prostatic
hyperplasia (BPH), and analyzed the levels of expression and localization of TGF
beta receptor types TbetaRI and TbetaRII in these patients as compared to
selected BPH controls. RESULTS: The prostatic epithelial compartment seemed to be
a primary target site for finasteride action, since we observed moderate to
severe glandular atrophy after 4-6 months of treatment. TGF-beta receptors were
upregulated in treated cases. We assessed a twofold increase in TbetaRII mRNA
levels in treated cases as compared to controls. An increase in both TbetaRI and
TbetaRII at the protein level by immunostaining was observed, which also provided
a helpful means for detecting glands undergoing regression. CONCLUSIONS: We
conclude that finasteride may modulate the TGF-beta signaling system to promote
changes leading to apoptosis of epithelial cells and prostatic glandular atrophy.
PMID- 9759701
TI - Effects of long-term treatment with Serenoa repens (Permixon) on the
concentrations and regional distribution of androgens and epidermal growth factor
in benign prostatic hyperplasia.
AB - BACKGROUND: The n-hexane lipido-sterol extract of Serenoa repens (LSESr,
Permixon, Pierre Fabre Medicament, Castres, France), a phytotherapeutic agent
used in the treatment of benign prostatic hyperplasia (BPH), has a multisite
mechanism of action including inhibition of types 1 and 2 5alpha-reductase and
competitive binding to androgen receptors in prostatic cells. Here, the response
of testosterone (T), dihydrotestosterone (DHT), and epidermal growth factor (EGF)
in BPH tissue of patients treated with LSESr (320 mg/day for 3 months) is
analyzed. METHODS: BPH samples were sectioned in periurethral, subcapsular, and
intermediate regions: in each region T, DHT, and EGF were determined by
radioimmunoassay after purification on celite columns or Sep-pak C18 cartridges.
RESULTS: In the untreated group, T, DHT, and EGF presented the highest
concentrations in the periurethral region (615 +/- 62 (SE) pg/g tissue, 7,317 +/-
551 pg/g tissue, and 20.9 +/- 3.3 ng/g tissue, respectively) with respect to the
peripheral subcapsular region (425 +/- 45 pg/g tissue, 4,215 +/- 561 pg/g tissue,
and 10.8 +/- 1.4 ng/g tissue, respectively). In the LSESr-treated group, a
statistically significant reduction was observed, mainly in the periurethral
region of DHT (2,363 +/- 553 pg/g tissue, P < 0.001) and EGF (6.98 +/- 2.48 ng/g
tissue, P < 0.01), with increased T values (1,023 +/- 101 pg/g tissue, P <
0.001). CONCLUSIONS: The decrease of DHT and the rise of T in BPH tissue of
patients treated with Permixon confirms the capacity of this drug to inhibit in
vivo 5alpha-reductase in human pathological prostate. A marked decrease of EGF,
associated with DHT reduction, was also observed. These biochemical effects,
similar to those obtained with finasteride, are particularly evident in the
periurethral region, whose enlargement is responsible for urinary obstruction,
with respect to the subcapsular region. A possible speculation is that the
preferential reduction of DHT and EGF content in the periurethral region is
involved in the clinical improvement of the obstructive symptoms in BPH during
LSESr therapy.
PMID- 9759703
TI - L6 monoclonal antibody binds prostate cancer.
AB - BACKGROUND: Radioimmunotherapy (RIT) is a promising new modality for targeted,
systemic delivery of radionuclides specifically to sites of androgen-independent
metastatic prostate cancer. To be effective, RIT requires an antibody with
specificity for malignant cells and appropriate pharmacokinetics in the body.
METHODS: Specific binding of the L6 monoclonal antibody to prostate cancer cell
lines or cell lysates was determined by enzyme-linked immunoabsorbent assay
(ELISA), solid-phase radioimmunoassay, and immunofluorescent staining.
Biodistribution, tumor uptake, and whole body and blood clearances of 125I-L6
were determined in nude mice bearing human prostate cancer xenografts. RESULTS:
The L6 monoclonal antibody showed strong binding to the lysates of PC3 and DU145
prostate cancer cell lines, and 66% binding to live PC3 cells. The L6 antibody
specifically targeted prostate cancer in PC3 and DU145-tumored nude mice, where
approximately 10% of the injected dose of 125I-L6 bound to prostate cancer. Low
normal organ uptake was found, and the blood clearances were similar in each
group of tumored mice. CONCLUSIONS: The L6 monoclonal antibody targets human
prostate cancer xenografts in nude mice and has low-normal organ uptake.
Therefore, further study of the radiolabeled L6 monoclonal antibody for RIT of
prostate cancer is warranted.
PMID- 9759704
TI - Expression of the aryl hydrocarbon receptor (AhR) and the aryl hydrocarbon
receptor nuclear translocator (ARNT) in fetal, benign hyperplastic, and malignant
prostate.
AB - BACKGROUND: Androgen-dependent tissue has been reported to be affected by
chemical ligands of the aryl hydrocarbon receptor (AhR), a ligand-activated
transcription factor, which heterodimerizes with the aryl hydrocarbon receptor
nuclear translocator protein (ARNT). METHODS: Fetal (n = 3), benign hyperplastic
(BPH) (n = 10), and carcinomatous (CaP) (n = 19) prostate tissues were analyzed
using immunohistochemistry. Western blot analysis was used to confirm the
identity of the recognized proteins. RESULTS: Immunoblotting of enriched
prostatic epithelial cells (EC) and stromal cells revealed constitutive
expression of bands at around 110 kDa and 90 kDa, using anti-AhR and anti-ARNT,
respectively. Immunohistology of the fetal specimens revealed heterogeneous
cytoplasmic and nuclear AhR expression of immature EC and mesenchymal cells.
Constitutive expression of AhR (primarily cytoplasmic) and ARNT (nuclear and
cytoplasmic) by the majority of adult basal and secretory EC, CaP, and smooth
muscle cells was confirmed in situ. The most intense anti-AhR/-ARNT reactivity
was found on smooth muscle cells, followed by EC and fibrocytes. Secretory BPH-EC
revealed significantly decreased AhR expression when compared to normal tissue
segments. By contrast, anti-AhR reactivity was frequently increased in the more
dedifferentiated tumor areas. CONCLUSIONS: These findings suggest that an
undefined physiologic AhR ligand(s) as well as environmental factors may exert
effects on EC and smooth muscle cells in the prostate through binding to these
receptors.
PMID- 9759706
TI - New concept of BPH: PCAR theory.
AB - BACKGROUND: A new concept of the pathophysiology of benign prostatic hyperplasia
(BPH), based upon the presumed circle area ratio (PCAR) theory, is described.
METHODS: The PCAR is the ratio of the area of the maximum horizontal section of
the prostate by transrectal sonography to the area of a presumed circle of which
the circumference is equal to the circumference of the maximum horizontal
section. This evaluates how closely the shape of the section approaches a circle.
RESULTS: A clear borderline was found at a PCAR of 0.75 in the postvoiding
residual urine volume (PVR) in many cases of BPH. Cases with the PCAR below this
level almost entirely showed a PVR below 30 ml, while cases with the PCAR over
this level demonstrated a wide distribution of PVR. CONCLUSIONS: Such a variety
of PVR in cases with the PCAR over 0.75 could be explained by the difference of
the elasticity of the surgical capsule (peripheral zone) in each case, which was
confirmed by a stress-strain test on extirpated specimens from the capsule at
surgery. We developed a new clinical parameter called the prostatic pressure
coefficient (PPC) to check elasticity, by means of a special balloon catheter
inserted into the prostatic urethra.
PMID- 9759705
TI - Characteristics of nonneoplastic human prostate tissue transplanted into nude
mice.
AB - BACKGROUND: Prostate tumors are characterized by sex hormone-associated growth
and mesenchymal-epithelial interactions. This study was conducted to establish an
ex vivo system where human prostate tissue could be maintained for a certain
period under conditions resembling the in vivo situation in man to provide an
experimental tool for investigation of prostate disease. METHODS: Human prostate
tissues (peripheral zone and transition zone) obtained by total cystectomy were
transplanted into the subcutis of male KSN nude mice for up to 24 weeks without
exogenous hormonal manipulation. RESULTS: Transplants could be maintained, and
although they showed several histological alterations, such as cystic dilation,
basal-cell hyperplasia, and squamous-cell metaplasia, many retained a nearly
normal appearance for the entire 24-week duration. Immunohistochemically,
androgen receptors were strongly positive in the nuclei of glandular epithelial
cells. Prostate-specific antigen (PSA) and prostatic acid phosphate (PAP) (both
from DAKO, Glostrup, Denmark), were also expressed in the cytoplasm. The
proportion of cells expressing proliferating cell nuclear antigen (PCNA) was not
related to the period of transplantation and did not differ between the
peripheral and transition zones. CONCLUSIONS: The results clearly demonstrate
that human prostate tissues transplanted into nude mice can maintain their
morphological and biological characteristics for up to 24 weeks. This provides a
simple and useful tool for basic research into human prostate neoplasia.
PMID- 9759708
TI - Wanted: a voice for the life sciences.
PMID- 9759707
TI - New sensitive discovery histoculture model for growth-inhibition studies in
prostate cancer and BPH.
AB - BACKGROUND: A new, total-immersion three-dimensional histoculture (TIH) method
was developed to evaluate growth of tissue containing a mixture of benign
prostate hyperplasia (BPH) and prostate cancer in vitro. METHODS: Efficacy of
inhibitors, such as genistein, was determined by measuring 3H-thymidine
incorporation per microgram protein. Inhibitory effects obtained in TIH were
compared to those in sponge-gel supported histoculture (SSH). RESULTS: 3H
thymidine incorporation was 2-5-fold higher in tissue cultured in TIH than in
SSH. The average inhibition by genistein at a concentration of 18 JIM was 73% in
TIH, vs. 31% in SSH. TIH also appeared to be more sensitive, since the lowest
concentration of genistein that significantly inhibited growth of BPH mixed with
prostate cancer tissue was 2.3 IJM, while in SSH the lowest concentration was 9.2
F,M. Although the within-assay coefficient of variation (CV) was similar for both
TIH and SSH, the between-assay CV was better in TIH. CONCLUSIONS: These data
suggest that TIH can be used as a discovery model for screening and evaluating
inhibitors of prostate tissue growth in vitro.
PMID- 9759709
TI - Panel urges caution on genetic testing for mental disorders.
PMID- 9759710
TI - US gene-therapy proposals come under fire.
PMID- 9759711
TI - Biology federation urged to widen focus.
PMID- 9759712
TI - UK life science students seek better deal.
PMID- 9759713
TI - France to set up co-ordinating committee.
PMID- 9759714
TI - Restrict genetic susceptibility tests.
PMID- 9759715
TI - Protein breakdown. Ubiquitous deja vu.
PMID- 9759717
TI - Isotope astrophysics. Sorting stardust.
PMID- 9759716
TI - Developmental biology. Birds of a feather flock together.
PMID- 9759718
TI - Behavioural genetics. Worming out social secrets.
PMID- 9759719
TI - Membrane fusion. SNARE the rod, coil the complex.
PMID- 9759720
TI - Origins of life. Buried beginnings.
PMID- 9759721
TI - Otto Wichterle (1913-98)
PMID- 9759722
TI - Gray's greyness.
PMID- 9759723
TI - Arsenic poisoning of Bangladesh groundwater.
PMID- 9759724
TI - Crystal structure of a SNARE complex involved in synaptic exocytosis at 2.4 A
resolution.
AB - The evolutionarily conserved SNARE proteins and their complexes are involved in
the fusion of vesicles with their target membranes; however, the overall
organization and structural details of these complexes are unknown. Here we
report the X-ray crystal structure at 2.4 A resolution of a core synaptic fusion
complex containing syntaxin-1 A, synaptobrevin-II and SNAP-25B. The structure
reveals a highly twisted and parallel four-helix bundle that differs from the
bundles described for the haemagglutinin and HIV/SIV gp41 membrane-fusion
proteins. Conserved leucine-zipper-like layers are found at the centre of the
synaptic fusion complex. Embedded within these leucine-zipper layers is an ionic
layer consisting of an arginine and three glutamine residues contributed from
each of the four alpha-helices. These residues are highly conserved across the
entire SNARE family. The regions flanking the leucine-zipper-like layers contain
a hydrophobic core similar to that of more general four-helix-bundle proteins.
The surface of the synaptic fusion complex is highly grooved and possesses
distinct hydrophilic, hydrophobic and charged regions. These characteristics may
be important for membrane fusion and for the binding of regulatory factors
affecting neurotransmission.
PMID- 9759725
TI - Abiotic nitrogen reduction on the early Earth.
AB - The production of organic precursors to life depends critically on the form of
the reactants. In particular, an environment dominated by N2 is far less
efficient in synthesizing nitrogen-bearing organics than a reducing environment
rich in ammonia. Relatively reducing lithospheric conditions on the early Earth
have been presumed to favour the generation of an ammonia-rich atmosphere, but
this hypothesis has not been studied experimentally. Here we demonstrate mineral
catalysed reduction of N2, NO2- and NO3- to ammonia at temperatures between 300
and 800 degrees C and pressures of 0.1-0.4 GPa-conditions typical of crustal and
oceanic hydrothermal systems. We also show that only N2 is stable above 800
degrees C, thus precluding significant atmospheric ammonia formation during hot
accretion. We conclude that mineral-catalysed N2 reduction might have provided a
significant source of ammonia to the Hadean ocean. These results also suggest
that, whereas nitrogen in the Earth's early atmosphere was present predominantly
as N2, exchange with oceanic, hydrothermally derived ammonia could have provided
a significant amount of the atmospheric ammonia necessary to resolve the early
faint-Sun paradox.
PMID- 9759726
TI - Object-based attention in the primary visual cortex of the macaque monkey.
AB - Typical natural visual scenes contain many objects, which need to be segregated
from each other and from the background. Present theories subdivide the processes
responsible for this segregation into a pre-attentive and attentive system. The
pre-attentive system segregates image regions that 'pop out' rapidly and in
parallel across the visual field. In the primary visual cortex, responses to pre
attentively selected image regions are enhanced. When objects do not segregate
automatically from the rest of the image, the time-consuming attentive system is
recruited. Here we investigate whether attentive selection is also associated
with a modulation of firing rates in area V1 of the brain in monkeys trained to
perform a curve-tracing task. Neuronal responses to the various segments of a
target curve were simultaneously enhanced relative to responses evoked by a
distractor curve, even if the two curves crossed each other. This indicates that
object-based attention is associated with a response enhancement at the earliest
level of the visual cortical processing hierarchy.
PMID- 9759727
TI - An analgesia circuit activated by cannabinoids.
AB - Although many anecdotal reports indicate that marijuana and its active
constituent, delta-9-tetrahydrocannabinol (delta-9-THC), may reduce pain
sensation, studies of humans have produced inconsistent results. In animal
studies, the apparent pain-suppressing effects of delta-9-THC and other
cannabinoid drugs are confounded by motor deficits. Here we show that a brainstem
circuit that contributes to the pain-suppressing effects of morphine is also
required for the analgesic effects of cannabinoids. Inactivation of the rostral
ventromedial medulla (RVM) prevents the analgesia but not the motor deficits
produced by systemically administered cannabinoids. Furthermore, cannabinoids
produce analgesia by modulating RVM neuronal activity in a manner similar to, but
pharmacologically dissociable from, that of morphine. We also show that
endogenous cannabinoids tonically regulate pain thresholds in part through the
modulation of RVM neuronal activity. These results show that analgesia produced
by cannabinoids and opioids involves similar brainstem circuitry and that
cannabinoids are indeed centrally acting analgesics with a new mechanism of
action.
PMID- 9759728
TI - Paired-spike interactions and synaptic efficacy of retinal inputs to the
thalamus.
AB - In many neural systems studied in vitro, the timing of afferent impulses affects
the strength of postsynaptic potentials. The influence of afferent timing on
postsynaptic firing in vivo has received less attention. Here we study the
importance of afferent spike timing in vivo by recording simultaneously from
ganglion cells in the retina and their targets in the lateral geniculate nucleus
of the thalamus. When two spikes from a single ganglion-cell axon arrive within
30 milliseconds of each other, the second spike is much more likely than the
first to produce a geniculate spike, an effect we call paired-spike enhancement.
Furthermore, simultaneous recordings from a ganglion cell and two thalamic
targets indicate that paired-spike enhancement increases the frequency of
synchronous thalamic activity. We propose that information encoded in the high
firing rate of an individual retinal ganglion cell becomes distributed among
several geniculate neurons that fire synchronously. Because synchronous
geniculate action potentials are highly effective in driving cortical neurons, it
is likely that information encoded by this strategy is transmitted to the next
level of processing.
PMID- 9759729
TI - Drosophila oocyte localization is mediated by differential cadherin-based
adhesion.
AB - In a Drosophila follicle the oocyte always occupies a posterior position among a
group of sixteen germline cells. Although the importance of this cell arrangement
for the subsequent formation of the anterior-posterior axis of the embryo is well
documented, the molecular mechanism responsible for the posterior localization of
the oocyte was unknown. Here we show that the homophilic adhesion molecule DE
cadherin mediates oocyte positioning. During follicle biogenesis, DE-cadherin is
expressed in germline (including oocyte) and surrounding follicle cells, with the
highest concentration of DE-cadherin being found at the interface between oocyte
and posterior follicle cells. Mosaic analysis shows that DE-cadherin is required
in both germline and follicle cells for correct oocyte localization, indicating
that germline-soma interactions may be involved in this process. By analysing the
behaviour of the oocyte in follicles with a chimaeric follicular epithelium, we
find that the position of the oocyte is determined by the position of DE-cadherin
expressing follicle cells, to which the oocyte attaches itself selectively. Among
the DE-cadherin positive follicle cells, the oocyte preferentially contacts those
cells that express higher levels of DE-cadherin. On the basis of these data, we
propose that in wild-type follicles the oocyte competes successfully with its
sister germline cells for contact to the posterior follicle cells, a sorting
process driven by different concentrations of DE-cadherin. This is, to our
knowledge, the first in vivo example of a cell-sorting process that depends on
differential adhesion mediated by a cadherin.
PMID- 9759730
TI - A function for lipoxygenase in programmed organelle degradation.
AB - Membrane-enclosed organelles, a defining characteristic of eukaryotic cells, are
lost during differentiation of specific cell types such as reticulocytes (an
intermediate in differentiation of erythrocytes), central fibre cells of the eye
lens, and keratinocytes. The degradation of these organelles must be tightly
regulated with respect to both the time of activation and the specificity of
membrane degradation. The expression of 15-lipoxygenase (15-LOX) peaks in
reticulocytes immediately before organelle degradation. Here we show that 15-LOX
integrates into the membranes of various organelles, allowing release of proteins
from the organelle lumen and access of proteases to both lumenal and integral
membrane proteins. In addition, by sparing the plasma membrane, 15-LOX shows the
required specificity for organellar membranes. Thus, the action of 15-LOX
provides a mechanism by which the natural degradation process can be explained.
This conclusion is supported by our finding that lipoxygenase expression in the
eye lens is restricted to the region at which organelle degradation occurs.
PMID- 9759731
TI - A protein conjugation system essential for autophagy.
AB - Autophagy is a process for the bulk degradation of proteins, in which cytoplasmic
components of the cell are enclosed by double-membrane structures known as
autophagosomes for delivery to lysosomes or vacuoles for degradation. This
process is crucial for survival during starvation and cell differentiation. No
molecules have been identified that are involved in autophagy in higher
eukaryotes. We have isolated 14 autophagy-defective (apg) mutants of the yeast
Saccharomyces cerevisiae and examined the autophagic process at the molecular
level. We show here that a unique covalent-modification system is essential for
autophagy to occur. The carboxy-terminal glycine residue of Apg12, a 186-amino
acid protein, is conjugated to a lysine at residue 149 of Apg5, a 294-amino-acid
protein. Of the apg mutants, we found that apg7 and apg10 were unable to form an
Apg5/Apg12 conjugate. By cloning APG7, we discovered that Apg7 is a ubiquitin-E1
like enzyme. This conjugation can be reconstituted in vitro and depends on ATP.
To our knowledge, this is the first report of a protein unrelated to ubiquitin
that uses a ubiquitination-like conjugation system. Furthermore, Apg5 and Apg12
have mammalian homologues, suggesting that this new modification system is
conserved from yeast to mammalian cells.
PMID- 9759732
TI - Retinoid-X receptor signalling in the developing spinal cord.
AB - Retinoids regulate gene expression through the action of retinoic acid receptors
(RARs) and retinoid-X receptors (RXRs), which both belong to the family of
nuclear hormone receptors. Retinoids are of fundamental importance during
development, but it has been difficult to assess the distribution of ligand
activated receptors in vivo. This is particularly the case for RXR, which is a
critical unliganded auxiliary protein for several nuclear receptors, including
RAR, but its ligand-activated role in vivo remains uncertain. Here we describe an
assay in transgenic mice, based on the expression of an effector fusion protein
linking the ligand-binding domain of either RXR or RAR to the yeast Gal4 DNA
binding domain, and the in situ detection of ligand-activated effector proteins
by using an inducible transgenic lacZ reporter gene. We detect receptor
activation in the spinal cord in a pattern that indicates that the receptor
functions in the maturation of limb-innervating motor neurons. Our results reveal
a specific activation pattern of Gal4-RXR which indicates that RXR is a critical
bona fide receptor in the developing spinal cord.
PMID- 9759733
TI - Position and orientation of the globular domain of linker histone H5 on the
nucleosome.
AB - It is essential to identify the exact location of the linker histone within
nucleosomes, the fundamental packing units of chromatin, in order to understand
how condensed, transcriptionally inactive chromatin forms. Here, using a site
specific protein-DNA photo-crosslinking method, we map the binding site and the
orientation of the globular domain of linker histone H5 on mixed-sequence chicken
nucleosomes. We show, in contrast to an earlier model, that the globular domain
forms a bridge between one terminus of chromatosomal DNA and the DNA in the
vicinity of the dyad axis of symmetry of the core particle. Helix III of the
globular domain binds in the major groove of the first helical turn of the
chromatosomal DNA, whereas the secondary DNA-binding site on the opposite face of
the globular domain of histone H5 makes contact with the nucleosomal DNA close to
its midpoint. We also infer that helix I and helix II of the globular domain of
histone H5 probably face, respectively, the solvent and the nucleosome. This
location places the basic carboxy-terminal region of the globular domain in a
position from which it could simultaneously bind the nucleosome-linking DNA
strands that exit and enter the nucleosome.
PMID- 9759734
TI - Taking knowledge from bench to bank.
PMID- 9759735
TI - Prevention and treatment of occupational mental disorders.
PMID- 9759736
TI - Impact of new criteria for diabetes on pattern of disease.
PMID- 9759737
TI - NSAIDs and Helicobacter pylori: therapeutic options.
PMID- 9759738
TI - Relevance of the first seizure.
PMID- 9759740
TI - Are all infections with Escherichia coli O157 associated with cattle?
PMID- 9759739
TI - Ethical issues in genetics of mental disorders.
PMID- 9759741
TI - Framingham at 50.
PMID- 9759742
TI - Epileptology of the first-seizure presentation: a clinical,
electroencephalographic, and magnetic resonance imaging study of 300 consecutive
patients.
AB - BACKGROUND: Prognosis and treatment of the first seizure depends on
identification of a specific epilepsy syndrome, yet patients with first seizures
are generally regarded as a homogeneous group. We studied whether it is possible
to diagnose specific epilepsy syndromes promptly by use of standard clinical
methods, electroencephalography (EEG) and magnetic resonance imaging (MRI).
METHODS: 300 consecutive adults and children presented with unexplained seizures.
We systematically collected clinical data from patients and witnesses, and
attempted to obtain an EEG within 24 h of the seizure. Where the EEG was
negative, a sleep-deprived EEG was done. MRI was done electively. FINDINGS: A
generalised or partial epilepsy syndrome was clinically diagnosed in 141 (47%)
patients. Subsequent analysis showed that only three of these clinical diagnoses
were incorrect. Addition of the EEG data enabled us to diagnose an epilepsy
syndrome in 232 (77%) patients. EEG within 24 h was more useful in diagnosis of
epileptiform abnormalities than later EEG (51 vs 34%). Neuroimaging showed 38
epileptogenic lesions, including 17 tumours. There were no lesions in patients
for whom generalised epilepsy was confirmed by EEG. Our final diagnoses were:
generalised epilepsy (23% of patients); partial epilepsy (58%); and unclassified
(19%). INTERPRETATION: An epilepsy syndrome can be diagnosed in most first
seizure patients. Ideally, an EEG should be obtained within 24 h of the seizure
followed by a sleep deprived EEG if necessary. MRI aids diagnosis and should be
done for all patients except for those with idiopathic generalised epilepsies and
for children with benign rolandic epilepsy.
PMID- 9759743
TI - Diabetes in older adults: comparison of 1997 American Diabetes Association
classification of diabetes mellitus with 1985 WHO classification.
AB - BACKGROUND: We aimed to compare the prevalence of abnormal glucose tolerance
identified by the 1985 WHO and the 1997 American Diabetes Association (ADA)
diagnostic categories based on information collected in the Cardiovascular Health
Study, an epidemiological study of elderly people. METHODS: We measured glucose
concentrations during fasting and 2 h after a 75 g oral glucose-tolerance test in
participants aged 65-100 years in the Cardiovascular Health Study. From a 1989
cohort, we analysed the glucose measurements of 4515 individuals without a
previous diagnosis of diabetes and of 262 additional measurements from an African
American cohort recruited in 1992-93. FINDINGS: In the 1989 cohort, the
prevalence of untreated diabetes with ADA diagnostic fasting criteria was 7.7%
versus a prevalence of 14.8% by the WHO criteria. In the African-American cohort,
the prevalence of untreated diabetes was 2.7% with ADA criteria and 11.8% with
WHO criteria. 3509 (77.7%) of the 4515 participants in the 1989 cohort had normal
glucose concentrations according to ADA fasting criteria, compared with 2401
(53.2%) according to WHO criteria. In the African-American cohort, the
corresponding numbers were 239 (91.2%) versus 153 (58.4%). All differences in
prevalence of abnormal glucose tolerance between ADA and WHO classifications were
significant (p<0.0001). INTERPRETATION: Among elderly individuals, there was a
significant difference in the prevalence of diabetes identified by the WHO
diagnostic criteria based on oral glucose-tolerance test and the ADA fasting
criteria. Consequently, many individuals currently classified as non-diabetic
according to ADA criteria would previously have had a diagnosis of diabetes
according to WHO criteria. Longitudinal studies are needed to assess the value of
the criteria in the identification of individuals at increased risk of diabetes
associated chronic complications.
PMID- 9759745
TI - Randomised trial of impact of school mental-health programme in rural Rawalpindi,
Pakistan.
AB - BACKGROUND: A school mental-health programme has been developed as a component of
the community mental-health programme in Rawalpindi, Pakistan. It has the
objective of improving the understanding of disorders of mental health in the
rural community. We aimed to assess the impact of a school mental-health
programme on the awareness of schoolchildren, their parents, friends who were not
attending school, and neighbours. METHODS: We chose two secondary schools for
boys and two for girls that were similar in terms of size, staff-pupil ratio, and
drop-out rates. 100 children aged 12-16 years (25 girls and 25 boys in each of
the study and control groups), 100 parents (one for each child), 100 friends who
did not attend school (one for each child), and 100 neighbours (one for each
child) were given a 19-item questionnaire before and after the study group had
had a 4-month programme of mental-health education. The maximum score for the
questionnaire was 16 points. FINDINGS: Before the school mental-health programme
the awareness of mental-health issues was poor (mean score 5.7-7.6) in the four
groups of participants. In the study group there was a significant improvement in
the mean scores after the school programme in the schoolchildren (mean
improvement 7.6 [95% CI 6.7-8.5], p<0.01), their parents (5.3 [4.5-6.1], p<0.01),
friends (5.1 [4.1-6.1], p<0.01), and neighbours (3.4 [2.6-4.2], p<0.01). In the
control group the difference in awareness was significant only in schoolchildren
(1.5 [0.5-2.3], p=0.01) and their friends (0.8 [0.3-1.3], p<0.01).
INTERPRETATION: The school programme succeeded in improving awareness of mental
health in schoolchildren and the community. The schoolchildren were receptive to
the programme, and shared their new understanding with family, friends, and
neighbours. Mental-health planners who wish to improve community awareness of
mental health, particularly in areas with low literacy rates, should consider
setting up school mental-health programmes.
PMID- 9759744
TI - Randomised controlled trial of Helicobacter pylori eradication in patients on non
steroidal anti-inflammatory drugs: HELP NSAIDs study. Helicobacter Eradication
for Lesion Prevention.
AB - BACKGROUND: The effect of Helicobacter pylori in patients receiving non-steroidal
anti-inflammatory drugs (NSAIDs) is unclear. We investigated the effects of H.
pylori eradication in patients with current or previous peptic ulceration,
dyspepsia, or both who continued to use NSAIDs. METHODS: 285 patients were
randomly assigned omeprazole 20 mg, amoxycillin 1000 mg, and clarithromycin 500
mg, twice daily (n=142, H. pylori eradication treatment), or omeprazole with
placebo antibiotics (n=143, controls) for 1 week. All patients received
omeprazole 20 mg once daily for 3 weeks until endoscopy, and, if the ulcer was
not healed, 40 mg once daily until repeat endoscopy at 8 weeks. Ulcer-free
patients with mild dyspepsia continued NSAIDs but not antiulcer treatment. We
investigated ulcers with endoscopy at 1, 3, and 6 months and with carbon-13
labelled urea breath test at 3 months. FINDINGS: The estimated probability of
being ulcer-free at 6 months was 0.56 (95% CI 0.47-0.65) on eradication treatment
and 0.53 (0.44-0.62) on on control treatment (p=0.80). Time to treatment failure
did not differ between groups for ulcers or dyspepsia alone, per-protocol
analysis, or final H. pylori status. 66% (58-74) of the eradication group
compared with 14% (8-20) of the control group had a final negative H. pylori
result (p<0.001). Fewer baseline gastric ulcers healed among eradication
treatment patients than among controls (72 vs 100% at 8 weeks, p=0.006).
INTERPRETATION: H. pylori eradication in long-term users of NSAIDs with past or
current peptic ulcer or troublesome dyspepsia led to impaired healing of gastric
ulcers and did not affect the rate of peptic ulcers or dyspepsia over 6 months.
PMID- 9759747
TI - Pulsating varicose veins.
PMID- 9759746
TI - Absence of Oxalobacter formigenes in cystic fibrosis patients: a risk factor for
hyperoxaluria.
AB - BACKGROUND: Patients with cystic fibrosis have an increased risk of
hyperoxaluria, and of subsequent nephrocalcinosis and calcium-oxalate
urolithiasis. Oxalate homoeostasis is controlled, in part, by the intestinal
bacterium, Oxalobacter formigenes. The loss of this bacterium from the gut flora
is associated with an increased risk of hyperoxaluria and calcium-oxalate
urolithiasis. We investigated whether the absence of O. formigenes and the
presence of hyperoxaluria are correlated in cystic fibrosis (CF) patients.
METHODS: Stool specimens from 43 patients with CF aged 3-9 years and from 21
similarly aged healthy volunteers were examined for O. formigenes by culture and
DNA analysis. At the same time, 24 h urine samples were collected and analysed
for oxalate and other factors that promote or inhibit stone formation. FINDINGS:
15 (71%) of 21 healthy volunteers but only seven (16%) of 43 CF patients were
colonised with O. formigenes. Detection of O. formigenes in six of these seven
patients required DNA-based identification, suggesting low numbers of colony
forming units, and the CF patient with normal numbers of O. formigenes was the
only one of the 43 patients who had not been treated with antibiotics. All seven
CF patients colonised with O. formigenes had normal urinary oxalate levels, but
19 (53%) of 36 patients not colonised with O. formigenes were hyperoxaluric, with
the most severe hyperoxaluria occurring in young patients. INTERPRETATION:
Absence of O. formigenes from the intestinal tract of CF patients appears to lead
to increased absorption of oxalate, thereby increasing the risk of hyperoxaluria
and its complications (eg, nephrocalcinosis, urolithiasis). Prolonged widespread
use of antibiotics, and alterations of the gastrointestinal tract that occur in
CF, may induce a permanent decolonisation in CF patients.
PMID- 9759748
TI - Atorvastatin and gemfibrozil for protease-inhibitor-related lipid abnormalities.
PMID- 9759749
TI - Protease inhibitors and adipocyte differentiation in cell culture.
PMID- 9759750
TI - Expression of sequence variants of endogenous retrovirus RGH in particle form in
multiple sclerosis.
PMID- 9759751
TI - Thyrotoxicosis incidence in Switzerland and benefit of improved iodine supply.
PMID- 9759752
TI - Eradication of human T-lymphotropic virus type 1 by allogeneic bone-marrow
transplantation.
PMID- 9759753
TI - Low blood pressure and early death of elderly people with dementia.
PMID- 9759754
TI - Thrombotic thrombocytopenic purpura after stenting and ticlopidine.
PMID- 9759755
TI - Action of anticardiolipin and antibodies to beta2-glycoprotein-I on trophoblast
proliferation as a mechanism for fetal death.
PMID- 9759756
TI - Rate of caesarean section and pregnancy outcome in women lawyers.
PMID- 9759757
TI - Nerve growth factor promising in diabetic neuropathy...and in HIV-1-related
neuropathy.
PMID- 9759758
TI - Green coffee beans may yield new class of anti-HIV-1 agents.
PMID- 9759759
TI - High-tech and low-tech predictors of stroke risk.
PMID- 9759761
TI - Careful smiles around the Blue Mosque in Turkey.
PMID- 9759760
TI - Martin Schechter: fighting the politicians with science.
PMID- 9759762
TI - Landmine ratification allows international law to go ahead.
PMID- 9759763
TI - Catalonia makes plans to help addicted doctors.
PMID- 9759764
TI - Stigma of mental illness. Foreword.
PMID- 9759766
TI - Mistaken identity.
PMID- 9759765
TI - Can the stigma of mental illness be changed?
PMID- 9759767
TI - UK mental health policy can alter the stigma of mental illness.
PMID- 9759768
TI - Stigma of manic depression: a psychologist's experience.
PMID- 9759769
TI - Stigma and disease: changing paradigms.
PMID- 9759770
TI - Cultural variation in the stigmatisation of mental illness.
PMID- 9759771
TI - Stigma: what can psychiatrists do about it?
PMID- 9759772
TI - Mental illness made public: ending the stigma?
PMID- 9759773
TI - Access to the dead: the role of relatives in the aftermath of disaster.
PMID- 9759774
TI - Peer review of grant applications.
PMID- 9759775
TI - Peer review of grant applications.
PMID- 9759776
TI - Peer review of grant applications.
PMID- 9759777
TI - Peer review of grant applications.
PMID- 9759778
TI - Cystic fibrosis and Young's syndrome.
PMID- 9759779
TI - Cystic fibrosis and Young's syndrome.
PMID- 9759780
TI - Diagnostic techniques for ventilator-associated pneumonia.
PMID- 9759781
TI - Eclampsia studies in developing countries.
PMID- 9759782
TI - Haemochromatosis and type 2 diabetes.
PMID- 9759783
TI - Origins of BSE.
PMID- 9759784
TI - ACE inhibitors and pneumonia.
PMID- 9759785
TI - Decrease of blood pressure by ventrolateral medullary decompression in essential
hypertension.
PMID- 9759786
TI - Lupus-like syndrome associated with simvastatin.
PMID- 9759787
TI - Oxyphilic parathyroid adenoma and lithium therapy.
PMID- 9759788
TI - US transplant system.
PMID- 9759789
TI - Patient recruitment in Helicobacter pylori drug trials.
PMID- 9759790
TI - 12th World AIDS Conference.
PMID- 9759791
TI - Intellectual property protection and pharmaceuticals.
PMID- 9759793
TI - What prevents hospitalizations and relapse from asthma?
PMID- 9759794
TI - A 7-year-old girl with cerebral palsy and multiple warts.
PMID- 9759795
TI - Prevalence of sensitization to aeroallergens in California patients with
respiratory allergy. Allergy Skin Test Project Team.
AB - BACKGROUND: The number of allergy skin tests required to evaluate patients with
respiratory allergy has recently been challenged by the managed care community.
OBJECTIVES: The purpose of this study was to determine which aeroallergens are
prevalent in patients with respiratory allergy (allergic rhinitis and bronchial
asthma) in California. METHODS: Utilizing aeroallergens thought to be relevant
from recent aerobiologic and botanic data, 141 allergic and 17 asymptomatic
control subjects were tested for the prevalence of 103 allergens. A standardized
prick puncture technique and standardized interpretation of wheal/flare responses
were utilized using the same lot of allergen for 13 allergy practices distributed
throughout California. Frequency curves based on prevalence were established to
determine the number of tests required to give up to 90% of positive responses
for tree, weed and grass pollen, mold spores, and miscellaneous allergens which
included house dust mite, cat, dog, and cockroach allergens. RESULTS: Positive
responses in allergic subjects for grasses ranged from 46% to 54%, for weeds 19%
to 37%, and for trees 10% to 42%. For molds the range was from 11% to 22%. The
response rate for Dermatophagoides pteronyssinus was 53%, for Dermatophagoides
farinae 42%, for cat pelt 39% and cat hair 37%, for cockroach 23% and dog dander
19%. Asymptomatic control subjects responded to only 4% of all allergens tested.
Ninety percent of all positive tests required three miscellaneous allergens
(house dust mite, cat, and cockroach), 9 molds, 2 grasses, 16 weeds, and 27 trees
for a total of 57 allergens (56% of total tested). There was no clear
relationship between locale and specific allergen response, probably related to
the limited number of subjects tested and variability within the same geographic
region. Several seldom tested tree and weed allergens showed a higher prevalence
rate than several commonly tested for allergens. CONCLUSIONS: This preliminary
study suggests that approximately 57 aeroalleroens might be adequate to detect
90% of all positive responses in patients with respiratory allergy in California.
This study was limited by subject number and variability between study sites. It
is hoped a standardized model can be developed from this pilot study to
definitively determine which aeroallergens are relevant in the United States.
PMID- 9759796
TI - Evaluation of olopatadine, a new ophthalmic antiallergic agent with dual
activity, using the conjunctival allergen challenge model.
AB - BACKGROUND: An ophthalmic antiallergic agent with selective H1 antihistaminic and
mast cell stabilizing properties has been developed. OBJECTIVES: To evaluate
efficacy and safety, determine optimal concentration, and demonstrate onset and
duration of action of this new drug, olopatadine. METHODS: This was a placebo
controlled, randomized, double-masked, parallel-group, single-center study with
five outpatient visits at least 7 days apart. Ninety-eight healthy, allergy
positive, subjects with a recent history of active allergic conjunctivitis not
receiving current treatment participated. Conjunctival allergen challenge (CAC)
tests were performed on visits 1 and 2 to identify an allergen and concentration
that consistently elicited signs and symptoms of allergic conjunctivitis. On
visits 3, 4, and 5, CAC was performed 27 minutes, 8 hours, and 6 hours,
respectively, after instillation of one drop of olopatadine (0.01%, 0.05%, 0.1%,
or 0.15%) in one eye and placebo in the other. Both eyes were scored for the
intensity of itching and redness at 3, 10, and 20 minutes after the CAC. RESULTS:
All four concentrations of olopatadine were clinically and statistically superior
to placebo in preventing ocular itching at all evaluations and preventing redness
at most evaluations from immediately and 8 hours after drug administration. No
drug-related adverse events were reported. The 0.1% concentration was found to be
most effective. CONCLUSIONS: The results indicate that olopatadine ophthalmic
solution is safe and effective in the treatment of allergic conjunctivitis, with
the 0.1% concentration of olopatadine being optimal. The rapid onset and at least
8 hour duration of action of olopatadine indicates that the drug can be used
twice daily.
PMID- 9759797
TI - Immunohistochemical characterization of cellular infiltrate in nasal polyp from
aspirin-sensitive asthmatic patients.
AB - BACKGROUND: The immunopathologic mechanism of nasal polyp in aspirin-sensitive
asthma remains to be further defined. OBJECTIVE: To characterize the features of
the inflammatory cellular infiltrate in the nasal polyp tissue from aspirin
sensitive asthmatic patients. METHODS: We have taken nasal polyp tissue during
nasal polyp resection from 13 aspirin-sensitive asthma, 6 allergic, and 12 non
allergic subjects. Immunohistochemistry was employed to stain and enumerate the
individual inflammatory cell types using monoclonal antibodies against tryptase
(AA1) to identify mast cells, against secreted forms of eosinophil cationic
protein (EG2), to identify activated eosinophils, against neutrophil elastase
(NE) for neutrophils and against T cell surface markers (CD3) to identify total T
cells. RESULTS: There were no significant differences in AA1 + cells among three
groups (P>.05). EG2 + cells tended to be higher in ASA-sensitive asthmatic
patients than in allergic and non-allergic subjects, but no statistical
significance was observed. NE+ cells were found in most subjects of the three
groups and their numbers were significantly higher in allergic subjects than in
aspirin-sensitive asthma (P<.05). Some patients had CD3+ cells with no
statistical significance among the three groups. Significant correlation was
found in numbers between NE+ cell and AA1+ cell (r=.44, P=.01), and between NE+
cell and EG2+ cell (r=.40, P=.02). CONCLUSION: These findings suggested that
major effector cells such as mast cells and eosinophils might be placed in the
center of the inflammatory response of nasal polyps, regardless of their
association with aspirin sensitivity.
PMID- 9759798
TI - A 3-month comparison of formoterol with terbutaline via turbuhaler. A placebo
controlled study.
AB - BACKGROUND AND AIM: Oxis Turbuhaler is a new dry powder formulation of long
acting beta2-agonist formoterol. This study compared the efficacy and safety of
regular use of the long-acting beta2-agonist formoterol and the short-acting
terbutaline for 3 months in patients with asthma. METHOD: After 1-week run-in,
343 patients received either formoterol 12 microg bid (F) (delivered dose of 9
microg), terbutaline 500 microg qid (T) or placebo qid, in a parallel-group,
double-blind, randomized manner. They had a mean of 61% of predicted forced
expiratory volume in 1 second (FEV1) and a mean reversibility of 26%. Eighty-nine
percent used inhaled corticosteroids. RESULTS: During run-in mean morning peak
expiratory flow (PEF L/min) for F was 366 and 348 for T, and 344 for placebo (P).
The F group improved morning PEF significantly compared with P (P = .0022) and T
(P = .0001). Changes from run-in were + 18, -1.5, and +5 L/min after F, T, and P,
respectively. The F group was statistically significantly better than P and T in
increasing evening PEF and in reducing night-time asthma. The F and T
statistically significantly reduced the use of rescue medication compared with P.
The bronchodilating response to the study drug and to an additional 1.25 mg
terbutaline was of the same magnitude before and throughout the study. No
statistically significant treatment-by-time interaction was observed (P > .20).
There were no adverse effects of clinical relevance. CONCLUSION: Formoterol
Turbuhaler, 12 microg bid, was more effective than terbutaline Turbuhaler, 0.5 mg
qid, and placebo. Regular use of formoterol or terbutaline did not significantly
influence the response to additional inhalation of terbutaline.
PMID- 9759799
TI - Theophylline inhibits the late asthmatic response to nighttime antigen challenge
in patients with mild atopic asthma.
AB - BACKGROUND: Inhaled antigen at night causes a more pronounced late asthmatic
response (LAR) when compared with daytime challenges. Chronopharmacology with
controlled-release theophylline given in the evening leads to a peak serum
theophylline concentration (STC) in early morning which coincides with LAR that
follows an evening challenge. OBJECTIVE: To evaluate the effect of controlled
release theophylline given with the evening meal on the immediate asthmatic
response (IAR) and LAR following nighttime antigen challenge in patients with
mild atopic asthma. METHODS: To qualify, subjects underwent antigen
bronchoprovocation by graded nebulization until the IAR (fall in FEV1 of > or
=20%) occurred; spirometry was then measured hourly for 8 hours to establish the
presence of LAR (fall in FEV1 > or =15%). After 2 weeks of randomized, double
blind crossover treatment with either theophylline (target STC of 10 to 15 mg/L,
(56 to 83 micromol/L)) or placebo, inhaled antigen challenge was performed at 10
PM in each subject. FEV1 values were measured immediately and then hourly for 8
hours following antigen challenge. RESULTS: Twelve subjects completed the study.
During the placebo phase, the maximal fall in FEV1 during LAR was 39 +/- 3% (mean
+/- SEM) compared with 31 +/- 4% fall during theophylline treatment phase (P =
.01). A reduction in LAR occurred despite higher dose (P <.05) of inhaled antigen
during theophylline phase, which would have been expected to result in a more
pronounced LAR. Serum theophylline concentration at 8 AM on the day following
antigen challenge was 9.6 +/- 1.1 mg/L (53 +/- 6 micromol/L). CONCLUSION:
Nocturnal administration of controlled-release theophylline increases the
tolerance to inhaled antigen and reduces severity of LAR. Because the LAR is
linked to airway inflammation, these data support the possibility of
antiinflammatory effects associated with theophylline use.
PMID- 9759800
TI - Aspirin and paracetamol tolerance in patients with nimesulide-induced urticaria.
AB - BACKGROUND: The administration of aspirin and other nonsteroidal anti
inflammatory drugs in patients sensitive to nimesulide might be hazardous.
OBJECTIVE: To assess the tolerance to both acetaminophen (paracetamol) and
aspirin in patients with a history of urticaria induced by nimesulide. METHODS:
Nine patients with a history of nimesulide intolerance were submitted to single
blind, placebo-controlled peroral challenges with increasing doses of
acetaminophen and aspirin. RESULTS: Acetaminophen was tolerated by all patients,
whereas two experienced immediate systemic urticaria after the administration of
125 mg of aspirin. CONCLUSION: Acetaminophen and aspirin are well tolerated by
most nimesulide-sensitive patients. Since a minority of patients show aspirin
sensitivity, tolerance of this agent should always be ascertained by properly
performed peroral challenges.
PMID- 9759801
TI - Behavioral and environmental factors associated with acute exacerbation of
asthma.
AB - BACKGROUND: The relapse rate following treatment for acute asthma is high. While
previous studies have evaluated the utility of pulmonary function measurements to
identify patients likely to relapse, the results are conflicting. The purpose of
this study was to evaluate other correctable, risk factors that may be associated
with relapse. PARTICIPANTS: Two hundred twenty-three patients treated in the
emergency department during 1994, including those either admitted or discharged.
METHODS: Patient interviews to identify behavioral and environmental risk factors
for asthma exacerbation. Telephone contact and medical record review to determine
incidence of relapse. RESULTS: Two hundred twenty-three patients were enrolled of
whom follow-up data were available for 152 (68%). Twenty-one percent of the
patients relapsed within 14 days. Relapse was associated with the lack of an
identifiable primary care physician and inability to obtain discharge
medications. There was no relationship between relapse and the use of a spacer,
hypoallergenic pillow or mattress cover, cigarette smoking, the presence of pets
in the home, or weekly carpet cleaning. CONCLUSION: Even following
hospitalization for acute asthma, there is a significant relapse rate. Improving
patients' access to primary care physicians and to appropriate medications may
decrease the relapse rate. Although a significant portion of patients have
behavioral and environmental risk factors for asthma exacerbation including
cigarette smoking and failure to maintain a hypoallergenic environment, these
factors are not associated with short-term relapse.
PMID- 9759803
TI - IgE-sensitization to cellular and culture filtrates of fungal extracts in
patients with atopic dermatitis.
AB - BACKGROUND: Patients with atopic dermatitis may experience exacerbations of
eczema triggered by various inflammatory stimuli. One mechanism may be IgE
mediated reactions to dermatophytes since these patients are more likely to
acquire skin infections with dermatophytes and may become sensitized. OBJECTIVE:
This study investigates IgE-sensitization to fungi in patients with atopic
dermatitis and compares the biologic activity of culture filtrates and cellular
fungal extracts. The following allergen extracts were provided as culture
filtrates and cellular extracts: Candida albicans, Fusarium moniliforme, and
Penicillium notatum. In addition, Pityrosporum ovale and Trichophyton rubrum
cultures were included in the test panel. METHODS: Fifteen patients with clinical
findings suggesting dermatophytosis and 11 controls were selected. Each subject
was tested by leukocyte histamine release and skin prick test to each fungal
extract. The extracts were separated and reduced by sodium dodecylsulfate
polyacrylamide gel electrophoresis and analyzed by IgE-immunoblotting with sera
from all study subjects. RESULTS: Fourteen patients (93%) reacted to one or
several fungal extracts by releasing histamine when challenged in vitro. By
immunoblotting experiments, patient sera showed binding to a wide range of
components in all extracts. Patient sera recognized allergenic components shared
by culture filtrates and cellular extracts but with higher frequent and greater
intensity in culture filtrates. Although culture filtrates generated more
frequent and potent IgE-reactions than the cellular extracts, the difference was
not statistically significant. Biologic potency was similar when evaluated by
skin prick tests and leukocyte histamine release. CONCLUSION: Patients with
atopic dermatitis may develop specific IgE-antibodies to a number of fungi as
demonstrated by IgE-immunoblotting. In selected patients, fungi may trigger an
IgE-mediated reaction that may contribute to the exacerbation of eczema.
Approximately, one-half of the patients, however, produced IgE-antibodies to
fungal (glyco)proteins without a significant histamine release or skin test
response possibly because of nonspecific interaction with carbohydrate moieties
on IgE and poor biologic activity of IgE antibodies directed to cross-reactive
carbohydrate determinants of fungal glycoproteins. This warrants caution when
interpreting clinical relevance of serologic measurements of fungal IgE
antibodies.
PMID- 9759802
TI - Exacerbation of premenstrual asthma caused by an oral contraceptive.
AB - BACKGROUND: The relationship between sex hormones and asthma has not been
clarified. Studies have suggested a potential beneficial effect of exogenous sex
hormones and/or contraceptive pills on asthma in premenopausal females whereas
the data for postmenopausal females are inconsistent. CASE REPORT: A 33-year-old
woman suffering from asthma with premenstrual exacerbations had a stable course
until she began taking oral contraceptives. At that time she experienced clinical
deterioration of her asthma associated with decline of pulmonary function tests.
No other precipitating factors were identified. After discontinuing the
contraceptives, her condition returned to baseline. CONCLUSION: We found only two
reports of worsening of asthma related to hormonal therapy (estrogen in one case,
contraceptive pills in the other) in premenopausal women. Our report, together
with these observations, suggests that in some premenopausal women exogenous sex
hormones and/or contraceptive pills may, contrary to expected, produce
exacerbation of asthma.
PMID- 9759804
TI - Severe anaphylaxis from rifamycin SV.
AB - BACKGROUND: Anaphylaxis to topical application of rifamycin SV, which is used
topically in the fields of surgery and dermatology, is rare. METHODS: We report
two cases of systemic reactions occurring after local administration of rifamycin
(Rifocine, Gruppo Lepetit, Italy). Both of them needed repeated intermittent
topical applications. Skin prick tests with Rifocine constituents were performed
on our patients, and also on ten atopic and ten nonatopic subjects. Although an
old investigative tool, Prausnitz-Kustner (P-K) test was also performed on one of
the patient's spouses to show passive transfer and the IgE-mediated mechanism.
RESULTS: Allergy assessment with skin tests on the patients were negative for
aeroallergens, latex, and Rifocine constituents (except rifamycin SV). The
patients' prick tests with rifamycin SV were positive, and the control subjects
were negative. P-K testing was positive. CONCLUSION: Two case reports support the
existence of IgE-mediated reactions to rifamycin SV. IgE-mediated anaphylactic
reactions from rifamycin SV appear to be extremely rare.
PMID- 9759805
TI - Association between giardiasis and allergy.
AB - BACKGROUND: Previous studies have indicated that there may be an association
between infection by the intestinal protozoan Giardia lamblia and the expression
of allergic disease. OBJECT: We evaluated a group of children who attended the
Outpatient Clinic of the Children's Hospital in Caracas, Venezuela, a group in
which both allergic disease and giardiasis were common. METHODS: We performed
feces examination and measured total and specific serum IgE (immunoglobulin E) in
these children. RESULTS: We found that 70% of the children infected with G.
lamblia presented symptoms of allergy, in contrast to 43% of the non-Giardia
parasitized group (P <.05). In addition, the G. lamblia parasitized children
showed significantly higher levels of total serum IgE (1194 IU/mL) than the non
Giardia group (822 IU/mL) (P <.005). Children infected with G. lamblia showed
higher levels of specific serum IgE antibody against food allergens compared both
with the non-parasitized group (P <.0001) and children infected with parasites
other than Giardia (P <.05). In contrast, IgE responses against the house dust
mite Dermatophagoides pteronyssinus were similar in all the groups studied.
CONCLUSIONS: These results reveal a clear relationship between giardiasis and
allergy, possibly because infection by this protozoon enhances sensitization
towards food antigens, due to increased antigen penetration through damaged
intestinal mucosa.
PMID- 9759807
TI - Anaphylaxis to rabbit: a case report.
AB - BACKGROUND: While rabbits are common as pets, severe allergic reactions to
domestic rabbits in homes are unusual. Typically, allergic manifestations are
mild to moderate allergic rhinitis, conjunctivitis, pruritus and/or asthma in
laboratory animal caretakers with frequent exposure. METHODS: We report an atopic
child with a severe allergic reaction following inhalant exposure to a rabbit. We
performed percutaneous skin tests and determined serum-specific IgE to commercial
preparation of rabbit epithelium and extracts of rabbit fur and serum. RESULTS:
Percutaneous skin test was positive to rabbit epithelium. The patient had
elevated serum-specific IgE to rabbit epithelium and fur but not to rabbit serum.
PMID- 9759806
TI - Relationships of race and socioeconomic status with prevalence, severity, and
symptoms of asthma in Chicago school children.
AB - BACKGROUND: Asthma mortality rates in Chicago are among the highest in the United
States, with substantially greater rates in poor and minority populations. How
much of the differential can be attributed to differences in prevalence versus
severity or access to care has not been determined. OBJECTIVE: To examine rates
of asthma prevalence, severity, and symptoms and to explore the relationships of
these rates to race and socioeconomic status in a random sample of Chicago school
children. METHODS: Self-administered survey. RESULTS: Overall, rates of asthma
were higher than previously reported, with 16% of students in the stratified
cluster random sample of 3,670 children in the 7th and 8th grades having had
asthma. Prevalence rates were significantly higher in schools with >98% African
Americans than in other schools, with the highest prevalence rates seen in
African American schools in low income neighborhoods. Rates were associated with
the percent of African American children in the school and with median income of
the school's census tract. Relationships were most consistent with indices of
more severe disease. CONCLUSIONS: Asthma prevalence is higher than previously
noted, with rates greatest in minority and low income populations. Differences
are more striking for measures of severity than for symptoms of wheezing, but are
far less than previously reported differences in mortality, suggesting that
additional factors, such as differential access to continuous health care, may be
affecting high death rates from asthma in Chicago.
PMID- 9759808
TI - Legg-Calve-Perthes disease in girls. A comparison of the results with those seen
in boys.
AB - We reviewed the records and roentgenograms of all patients with Legg-Calve
Perthes disease who had been seen at our institution between 1940 and 1996. One
hundred and five girls (122 hips) and 470 boys (531 hips) were identified. Thus,
18 per cent of the 575 patients in the present series were girls. Seventeen (16
per cent) of the girls and sixty-one (13 per cent) of the boys had bilateral
involvement. Although more girls than boys had severe involvement of the femoral
head and the lateral pillar, we could not detect a significant difference between
the two groups with respect to the distribution of the involvement of the hips
according to the system of Catterall or the lateral pillar classification (p >
0.05, beta = 0.99). Serial roentgenograms that showed all four stages of the
disease according to the system of Waldenstrom were available for fifty-two hips
in girls and 184 hips in boys. A review of these roentgenograms revealed that the
average ages of the girls at the stages of necrosis, fragmentation,
reossification, and remodeling were 6.8, 7.3, 7.9, and 9.5 years, respectively,
whereas the average ages of the boys were 6.8, 7.3, 7.9, and 9.9 years,
respectively. Girls, however, had closure of the affected proximal femoral physis
at an average age of 12.9 years, whereas boys had closure at an average age of
15.8 years. Therefore, girls had a shorter potential period for remodeling of the
femoral head (average, 3.4 years) compared with boys (average, 5.9 years). Sixty
four girls (seventy-eight hips) and 363 boys (416 hips) had reached skeletal
maturity by the time of the latest follow-up and were evaluated according to the
system of Stulberg et al.; we could not detect a significant difference between
boys and girls with respect to the distribution of the hips according to this
system (p > 0.05, beta = 0.99). Although the numbers were too small for
statistical analysis, our findings suggest that boys and girls who have the same
Catterall or lateral pillar classification at the time of the initial evaluation
can be expected to have similar outcomes according to the classification system
of Stulberg et al.
PMID- 9759809
TI - Levels of carbon dioxide in helmet systems used during orthopaedic operations.
AB - The use of isolation helmets has gained popularity as a method of possible
protection of the operating-room personnel from diseases that can be transmitted
during operative procedures. However, the use of these systems has been
associated with a variety of symptoms, including fatigue, diaphoresis, nausea,
headache, and irritability. These symptoms have often been attributed to the
mental stress of the operative procedure or the physical discomfort of the
helmet. As far as we know, no manufacturers include the measured levels of carbon
dioxide or the rate of air exchange of their helmet system. A possible common
cause of discomfort with helmet systems is the level of carbon dioxide to which
the person wearing the device is exposed. We measured the levels of carbon
dioxide in four helmet systems from three different manufacturers during light
exercise designed to approximate the exertion during an orthopaedic operation.
All but one unit failed to meet the exposure limits recommended by the National
Institute for Occupational Safety and Health and the Occupational Safety and
Health Administration regarding exposure to carbon dioxide. One unit, the
Stackhouse Freedom Aire self-contained system, did meet these standards, but the
levels of carbon dioxide in this helmet were more than 1000 per cent greater than
the ambient levels in air (440 parts per million compared with 4939 parts per
million). Isolation systems must be evaluated carefully not only for comfort but
also for the physiological effects caused by exposure to elevated levels of
carbon dioxide. Operating-room personnel who use such systems should be aware
that many of the physical symptoms that they experience may be associated with
elevated levels of carbon dioxide.
PMID- 9759810
TI - Survival analysis of hips treated with core decompression or vascularized fibular
grafting because of avascular necrosis.
AB - Avascular necrosis of the femoral head is a multifaceted process that leads to
articular incongruity and subsequent osteoarthrosis of the joint. Clinicians
concur that primary treatment should focus on preservation of the natural surface
of the joint; however, there has not been a consensus on how best to accomplish
this. While a number of therapeutic interventions have been reported, the
efficacy has varied markedly and there have been few statistical comparisons. The
purpose of the current study was to use statistical analysis to compare the
results of two widely used procedures, vascularized fibular grafting (614 hips;
480 patients) and core decompression (ninety-eight hips; seventy-two patients),
for the treatment of avascular necrosis. The patients were stratified according
to age and the stage of disease, and a survival analysis was performed with total
hip arthroplasty as the end point for failure. None of the eleven hips that had
Ficat stage-I disease needed a total joint replacement after being treated with
either regimen. Analysis of the hips that had stage-II disease revealed rates of
survival, at fifty months, of 65 per cent (twenty-eight of forty-three hips)
after core decompression and 89 per cent (ninety-nine of 111 hips) after
vascularized fibular grafting. For the hips that had Ficat stage-III disease, the
rates of survival at fifty months were 21 per cent (ten of forty-seven hips)
after core decompression and 81 per cent (405 of 500 hips) after vascularized
fibular grafting. Among the hips that had Ficat stage-II or III disease, the rate
of eventual total joint arthroplasty after vascularized fibular grafting was
significantly lower than that after core decompression (p < 0.0001). The results
indicate that the increased morbidity associated with vascularized fibular
grafting is justified by the associated delay in or prevention of articular
collapse in hips that have stage-II or III disease.
PMID- 9759811
TI - Magnetic resonance imaging of articular cartilage in the knee. An evaluation with
use of fast-spin-echo imaging.
AB - The purpose of this study was to demonstrate that specialized magnetic resonance
imaging provides an accurate assessment of lesions of the articular cartilage of
the knee. Arthroscopy was used as the comparative standard. Eighty-eight patients
who had an average age of thirty-eight years were evaluated with magnetic
resonance imaging and subsequent arthroscopy because of a suspected meniscal or
ligamentous injury. The magnetic resonance imaging was performed with a
specialized sequence in the sagittal, coronal, and axial planes. Seven articular
surfaces (the patellar facets, the trochlea, the femoral condyles, and the tibial
plateaus) were graded prospectively on the magnetic resonance images by two
independent readers with use of the 5-point classification system of Outerbridge,
which was also used at arthroscopy. Six hundred and sixteen articular surfaces
were assessed, and 248 lesions were identified at arthroscopy. Eighty-two
surfaces had chondral softening; seventy-five, mild ulceration; fifty-three, deep
ulceration, fibrillation, or a flap without exposure of subchondral bone; and
thirty-eight, full-thickness wear. To simplify the statistical analysis, grades 0
and 1 were regarded as disease-negative status and grades 2, 3, and 4 were
regarded as disease-positive status. When the grades that had been assigned by
reader 1 were used for the analysis, magnetic resonance imaging had a sensitivity
of 87 per cent (144 of 166), a specificity of 94 per cent (424 of 450), an
accuracy of 92 per cent (568 of 616), a positive predictive value of 85 per cent
(144 of 170), and a negative predictive value of 95 per cent (424 of 446) for the
detection of a chondral lesion. Interobserver variability was minimum, as
indicated by a weighted kappa statistic of 0.93 (almost perfect agreement). With
use of this readily available modified magnetic resonance imaging sequence, it is
possible to assess all articular surfaces of the knee accurately and thereby
identify lesions that are amenable to arthroscopic treatment.
PMID- 9759812
TI - Total knee arthroplasty in patients receiving Workers' Compensation.
AB - The poor outcomes in patients who have a low-back injury that was sustained while
they were on the job have been well described in many studies. The purpose of the
current study was to determine the influence of Workers' Compensation on the
outcome of total knee arthroplasty in forty-two patients who had been managed
between January 1980 and December 1993. There were thirty-two men and ten women,
and the mean age at the time of the operation was forty-eight years (range,
twenty-nine to sixty-eight years). These patients were directly matched with a
group of forty-two patients who were not receiving compensation. The two groups
were matched with regard to nine parameters: age, gender, obesity index,
preoperative deformity in the coronal plane, preoperative level of symptoms,
preoperative radiographic severity according to the criteria of Ahlback, method
of fixation, number of previous procedures, and duration of follow-up. After a
mean duration of follow-up of eighty months (range, forty-eight to 178 months),
the patients who were receiving compensation had a mean Knee Society score of 64
points (range, 25 to 100 points). Twelve (29 per cent) of the patients in this
group had an excellent or good clinical result, and thirty (71 per cent) had a
fair or poor result or had had a revision. The patients who were not receiving
compensation had a mean Knee Society score of 93 points (range, 57 to 100 points)
after a similar duration of follow-up. Thirty-seven patients (88 per cent) in
this group had an excellent or good clinical result, and five (12 per cent) had a
fair or poor result or had had a revision; the difference between the two groups
with regard to fair or poor results and revisions was significant (p < 0.01).
With the numbers available, no significant differences could be detected between
the two groups with regard to objective measurements of range of motion and
stability or with regard to radiographic alignment, the presence of radiolucent
lines, or the shedding of beads. On the basis of our findings, we believe that
surgeons should be aware that Workers' Compensation is one of several variables
that may have an untoward influence on the perceived outcome of total knee
arthroplasty.
PMID- 9759813
TI - Postoperative mortality after total hip arthroplasty. An analysis of deaths after
two thousand seven hundred and thirty-six procedures.
AB - We retrospectively determined the prevalence and nature of mortality as many as
ninety days after 2736 primary and revision total hip arthroplasties performed in
2002 patients by one surgeon at a teaching hospital between January 1969 and
December 1996. All but seventy-one of the patients had received prophylaxis
against venous thromboembolic disease. There were no intraoperative deaths, and
no events during the operation could be linked directly to postoperative
mortality. Eight deaths (mortality rate, 0.3 per cent) occurred within ninety
days after the 2736 procedures. Four deaths (mortality rate, 0.15 per cent)
occurred during the initial hospitalization. The cause of seven of the deaths was
determined. Three patients died as a result of preexisting disease (severe
hepatorenal disease, metastatic esophageal cancer, or severe cardiac disease),
and one patient died from sepsis with a gram-negative organism during a
thoracotomy eight days postoperatively. A bleeding complication that occurred
while the patient was receiving warfarin therapy led to the death of two other
patients; one of these deaths occurred in 1974 and the other, in 1982. At the
time that these patients were managed, the desired prothrombin time was
considered to be twice the control value. The remaining patient, who had had a
clip placed on the inferior vena cava after a pulmonary embolus occurred in 1970,
died secondary to acute, severe thrombosis of this vessel after a total hip
arthroplasty in 1971. The patient for whom the cause of death was not determined
had had an artificial aortic valve and had been receiving chronic warfarin
therapy. She died suddenly eighty-nine days postoperatively; no autopsy was
performed. No patient died as the direct result of a known pulmonary embolus. No
deaths related to venous thromboembolic disease or its prophylaxis or treatment
occurred after 1982 (1458 operations). We attribute this, in part, to reduced
levels of warfarin prophylaxis and improved management with warfarin. The ninety
day postoperative mortality rate after 2736 procedures performed over nearly
three decades was low (0.3 per cent). This span of time included the period
before the introduction of many current improvements in perioperative care, such
as routine intubation of patients under general anesthesia, continuous monitoring
of the electrocardiogram intraoperatively, and blood-gas determinations. When the
patients who died as a result of known, severe preexisting disease were excluded,
the mortality rate was 0.18 per cent (five of 2733).
PMID- 9759814
TI - Total hip arthroplasty after operative treatment of an acetabular fracture.
AB - Sixty-six primary total hip arthroplasties were performed to treat post-traumatic
osteoarthrosis that had developed following an acetabular fracture and subsequent
open reduction and internal fixation. The mean age of the patients at the time of
the total hip arthroplasty was fifty-two years (range, nineteen to eighty years).
The arthroplasty was performed with cement in forty-four hips and without cement
in twenty hips; in the remaining two hips, the acetabular component was inserted
without cement and the femoral component was inserted with cement (a so-called
hybrid procedure). Scarring from a previous procedure, retained hardware,
heterotopic bone, and residual osseous deformity and deficiency made the
procedure more complex than routine total hip arthroplasty in most patients.
However, only one of the sixty-six procedures was associated with an operative
complication. Three patients were lost to follow-up. The remaining sixty-three
patients were followed for a mean of 9.6 years (range, two to twenty years). The
mean duration of follow-up was 14.9 years for the acetabular components inserted
with cement, 11.6 years for the femoral components inserted with cement, 4.6
years for the femoral components inserted without cement, and 3.9 years for the
acetabular components inserted without cement. The mean Harris hip score improved
from 49 points preoperatively to 93 points at the latest follow-up evaluation for
the forty-six patients who did not have a revision procedure after the index
arthroplasty. Seventeen patients had a revision; sixteen revisions were performed
because of aseptic loosening of one or both components (nine acetabular and
eleven femoral components). Mechanical failure (radiographic loosening or
revision due to aseptic loosening) occurred in twenty-five hips. As determined
with use of the Kaplan-Meier method, the ten-year survival rate, with revision
due to aseptic loosening as the end point, was 78 per cent (95 per cent
confidence interval, 66 to 92 per cent) for the prosthesis as a whole (that is,
no revision of either component), 87 per cent (95 per cent confidence interval,
76 to 99 per cent) for the acetabular component, and 84 per cent (95 per cent
confidence interval, 72 to 97 per cent) for the femoral component. An age of less
than fifty years (p = 0.02), a weight of eighty kilograms or more (p = 0.047),
and large residual combined segmental and cavitary deficiencies in the acetabular
bone (p < 0.0001) were significant risk factors for revision because of aseptic
loosening. At the ten-year follow-up, none of the twenty-two acetabular
components that had been inserted without cement had been revised or demonstrated
radiographic loosening. The ten-year rate of failure due to aseptic loosening was
higher than that in many reported series of total hip arthroplasties performed
for other indications; this was probably partly because of the young mean age of
the patients, the high number of patients who had Charnley class-A involvement,
and the predominantly male cohort.
PMID- 9759815
TI - Treatment of infection with debridement and retention of the components following
hip arthroplasty.
AB - Forty-two patients (forty-two hips) who had an infection following a hip
arthroplasty were managed with open debridement, retention of the prosthetic
components, and antibiotic therapy. After a mean duration of follow-up of 6.3
years (range, 0.14 to twenty-two years), only six patients (14 per cent) -- four
of nineteen who had had an early postoperative infection and two of four who had
had an acute hematogenous infection -- had been managed successfully. Of the
remaining thirty-six patients, three (7 per cent of the entire group) were being
managed with chronic suppression with oral administration of antibiotics and
thirty-three (79 per cent of the entire group) had had a failure of treatment.
All nineteen patients who had a late chronic infection were deemed to have had a
failure of treatment. Debridement had been performed at a mean of six days
(range, two to fourteen days) after the onset of symptoms in the patients who had
been managed successfully and at a mean of twenty-three days (range, three to
ninety-three days) in those for whom treatment had failed. Debridement with
retention of the prosthesis is a potentially successful treatment for early
postoperative infection or acute hematogenous infection, provided that it is
performed in the first two weeks after the onset of symptoms and that the
prosthesis previously had been functioning well. In our experience, this
procedure has not been successful when it has been performed more than two weeks
after the onset of symptoms. Retention of the prosthesis should not be attempted
in patients who have a chronic infection at the site of a hip arthroplasty as
this approach universally fails.
PMID- 9759816
TI - Neuropathic arthropathy of the shoulder.
AB - We retrospectively reviewed the records of six men (seven shoulders) with
neuropathic arthropathy of the shoulder who were referred to our shoulder service
during a twenty-eight-year period (from 1969 through 1997). The etiology of the
neuropathic condition was syringomyelia in five patients (six shoulders) and
chronic alcoholism in one patient. Five patients (six shoulders) were initially
misdiagnosed, and seven operative procedures that were unrelated to the etiology
of the neuropathic condition were performed in four of these patients.
Radiographs revealed destruction of the shoulder joint and marked resorption of
the humeral head in all patients. Magnetic resonance images revealed a syrinx of
the central cord in all of the patients except for the one who had chronic
alcoholism.
PMID- 9759817
TI - The treatment of symptomatic os acromiale.
AB - During a four-year period, fourteen individuals (fifteen shoulders) who had been
seen at the shoulder service of our institution because of pain in the shoulder
had a radiographic finding of an os acromiale. On clinical examination, the pain
appeared to be due to an unstable os acromiale because the patients had point
tenderness over the acromion and pain on forward elevation of the shoulder. The
diagnosis of an os acromiale was confirmed on radiographs, magnetic resonance
images, or a bone scan. Eight patients had an associated tear of the rotator
cuff. The os acromiale was located in the pre-acromion in one shoulder, the meso
acromion in eleven shoulders, and the meta-acromion in three shoulders. At the
operation, the anterior aspect of the acromion was found to be unstable in all
shoulders. Eleven patients (twelve shoulders) had open reduction of the os
acromiale and insertion of an autogenous iliac-crest bone graft. Of those
patients, four (five shoulders) had open reduction and internal fixation with a
tension-band procedure with use of pins and wires. Only one of those shoulders
had a solid osseous union, and the other four shoulders had a non-union that was
due to a disruption of the fixation. The remaining seven patients (seven
shoulders) had open reduction and internal fixation with use of cannulated screws
and a tension-band construct; a solid osseous union was achieved in all but one
of them. One patient had excision of the pre-acromion, which relieved the pain.
Two patients who had had failed open reduction and internal fixation had excision
of a grossly unstable os acromiale in the meso-acromion; both patients had pain
and weakness after this procedure. Of the twelve shoulders that had open
reduction and bone-grafting, seven had union of the os acromiale; the average
time to radiographic and clinical union was nine weeks (range, seven to twenty
weeks). We concluded that, although it is rare, symptomatic unstable os acromiale
does occur and can be effectively treated with use of autogenous bone-grafting
and internal fixation with a rigid tension-band construct and cannulated screws.
PMID- 9759818
TI - The Coonrad-Morrey total elbow arthroplasty in patients who have rheumatoid
arthritis. A ten to fifteen-year follow-up study.
AB - Sixty-nine patients (seventy-eight elbows) who had rheumatoid arthritis were
managed with a Coonrad-Morrey total elbow arthroplasty between 1981 and 1986. At
the time of the present review, forty-one patients (forty-six elbows) were alive
and had been followed for at least ten years after the procedure (Group 1). The
remaining twenty-eight patients (thirty-two elbows) had died or had had a
revision less than ten years after the procedure or had been followed for less
than ten years (Group 2). The patients in Group 1 had a younger mean age at the
time of the procedure, but all other preoperative parameters were similar for
both groups. At the latest follow-up evaluation, 97 per cent of the elbows (forty
five of the forty-six in Group 1 and thirty-one of the thirty-two in Group 2)
were not painful or were only mildly painful. The mean arc of flexion-extension
was 28 to 131 degrees; this represents an increase of 13 degrees (15 degrees in
Group 1 and 7 degrees in Group 2) compared with the preoperative value. The mean
arc of pronation was 68 degrees, and the mean arc of supination was 62 degrees;
this represents an increase of 21 degrees. The results for seventy-four of the
seventy-eight elbows (all forty-six in Group 1 and twenty-eight of the thirty-two
in Group 2) were considered satisfactory by the patients. One patient thought
that the status of the elbow was unchanged compared with preoperatively, and
three thought that it was worse. Seventy-six of the seventy-eight elbows had long
term radiographic evaluation; the two remaining elbows were excluded because a
resection arthroplasty had been performed. There were two loose ulnar components;
one was associated with an infection, and the other had been causing no symptoms
at the time of the patient's death. In addition, both components were
radiographically loose in an elbow that had had a revision without cement after a
previous total elbow arthroplasty. Five bushings (7 per cent) were completely
worn, and six (8 per cent) were partially worn. Complications occurred in eleven
elbows (14 per cent) and were serious, necessitating reoperation, in ten (13 per
cent). Delayed complications included three avulsions of the triceps, two deep
infections, two ulnar fractures, and one fracture of an ulnar component. In
addition, two elbows were revised because of aseptic loosening. No patient had
persistent ulnar neuritis or serious skin complications. At the latest clinical
follow-up evaluation, according to the Mayo elbow performance score, forty-three
of the seventy-eight elbows had an excellent result; twenty-six, a good result;
seven, a fair result; and two (both in Group 2), a poor result. The rate of
survival of the prosthesis was 92.4 per cent, with 86 per cent good or excellent
and 14 per cent fair or poor results.
PMID- 9759819
TI - Anti-infective efficacy of antiseptic-coated intramedullary nails.
AB - The coating of medical devices with antimicrobial agents has recently emerged as
a potentially effective method for the prevention of device-related infections.
We examined the anti-infective efficacy of intramedullary nails coated with an
antiseptic combination of chlorhexidine and chloroxylenol in a rabbit model of
device-related infection after fixation of an open tibial fracture. The rabbits
were randomized to receive 2.8-by-100-millimeter stainless-steel tibial
intramedullary nails that either were uncoated or were coated with antiseptic.
After administration of anesthesia and preoperative antibiotic prophylaxis, a
tibial fracture was created and then reduced with insertion of the intramedullary
nail. A bacterial inoculum of 10(6) colony-forming units of Staphylococcus aureus
was injected into the intramedullary canal, and the wound was sutured.
Radiographs of the tibiae were made postoperatively, and the rabbits were
monitored daily. They were killed at six weeks, or earlier if there was
dehiscence of the wound, the fracture became grossly unstable, or the rabbit
failed to thrive. The use of the antiseptic-coated nails was associated with a
significantly lower rate of device-related osteomyelitis (two of twenty-two; 9
per cent) than the use of the uncoated nails (thirteen of twenty-one; 62 per
cent) (p = 0.0003). The radiographic and histopathological findings were
generally similar in the two groups of rabbits. Antiseptic agents were not
detected in serum. The results suggest that antiseptic-coated fracture-fixation
devices provide significant local protection against Staphylococcus aureus, which
is the most common cause of infections related to orthopaedic devices.
PMID- 9759820
TI - Function of the vascular endothelium after hypothermic storage at four degrees
Celsius in a canine tibial perfusion model. The role of adrenomedullin in
reperfusion injury.
AB - The function of the vascular endothelium after cold storage at 4 degrees Celsius
for one, three, five, and seven days was investigated in a canine tibial
perfusion model. Function was assessed in terms of changes in perfusion pressure,
changes in the concentration of endothelin in the venous effluent from the
perfused tibiae, adrenomedullin-induced vascular smooth-muscle relaxation, and
norepinephrine-induced pressor responses in the presence of acetylcholine, N(G)
monomethyl-L-arginine acetate (an inhibitor of nitric oxide synthesis), or
indomethacin (an inhibitor of prostaglandin synthesis) in phase 1 of the study.
In phase 2 of the study, the effect of the infusion of tetraethylammonium (a
potassium-channel blocker that inhibits the activity of endothelium-derived
hyperpolarized factor) was analyzed. The baseline perfusion pressures increased
in a time-dependent manner (p < 0.05). In tibiae that had been stored for one or
three days, the production of endothelin-1 was less than one picogram per
milliliter, but it markedly increased to a mean (and standard error of the mean)
of 8.7 +/- 3.2 and 10.8 +/- 4.3 picograms per milliliter in tibiae that had been
stored for five and seven days, respectively (p < 0.05). Acetylcholine attenuated
the norepinephrine-induced pressor response in all groups (storage at 4 degrees
Celsius for one, three, five, or seven days) compared with the response in the
control tibiae (p < 0.05). Perfusion of acetylcholine in the tibiae that had been
stored for three days significantly attenuated the pressor response to
norepinephrine compared with that in the tibiae that had been stored for five
days (p < 0.05). In the presence of N(G)-monomethyl-L-arginine acetate, the
norepinephrine-induced pressor response significantly increased only in the
tibiae that had been stored for one day (p < 0.05). In the presence of
indomethacin, the norepinephrine-induced pressor response significantly decreased
in the tibiae that had been stored at 4 degrees Celsius for one, three, or five
days (p < 0.05). Infusion of adrenomedullin relaxed vascular smooth muscle in the
tibiae that had been stored for one, three, five, or seven days (p < 0.05). In
phase 2 of the study, perfusion of tetraethylammonium in the presence of
acetylcholine increased the norepinephrine-induced pressor response in the tibiae
that had been stored at 4 degrees Celsius for seven days to a mean of 168 +/- 20
per cent, whereas perfusion with acetylcholine alone attenuated the
norepinephrine-induced pressor response to a mean of 54.6 +/- 3.7 per cent.
PMID- 9759821
TI - Angiosarcoma of the hand associated with chronic exposure to polyvinyl chloride
pipes and cement. A case report.
PMID- 9759822
TI - Failure of a stainless-steel femoral head of a revision total hip arthroplasty
performed after a fracture of a ceramic femoral head. A case report.
PMID- 9759823
TI - The use of ultrasonography in the diagnosis of occult fracture of the radial
neck. A case report.
PMID- 9759824
TI - Mechanoreceptors in joint function.
PMID- 9759825
TI - Current concepts review. Prophylactic use of antibiotics for procedures after
total joint replacement.
PMID- 9759826
TI - Peroneal nerve entrapment.
PMID- 9759827
TI - The prospective, randomized, double-blind clinical trial in orthopaedic surgery.
PMID- 9759828
TI - The effect of fibular malreduction on contact pressures in an ankle fracture
malunion model.
PMID- 9759829
TI - Posterior decompression and stabilization for spinal metastases. Analysis of
sixty-seven consecutive patients.
PMID- 9759830
TI - Allograft reconstruction of the acetabulum after resection of stage-IIB sarcoma.
Intermediate-term results.
PMID- 9759831
TI - Total hip arthroplasty with cement in patients less than twenty years old. Long
term results.
PMID- 9759832
TI - Wrong-site surgery.
PMID- 9759833
TI - Transcutaneous immunization with cholera toxin protects mice against lethal
mucosal toxin challenge.
AB - We recently reported that application of cholera toxin (CT) to the skin results
in transcutaneous immunization and induces a systemic Ab response to both CT and
coadministered Ags. In this paper, we demonstrate antitoxin IgG and IgA Abs in
sera, lung washes, and stool samples from immunized mice as well as a broad
spectrum of IgG subclasses (IgG1, IgG2a, IgG2b, and IgG3) in the sera. Mice
immunized with CT by the transcutaneous route exhibited significant protection
from intranasal challenge with a lethal dose of CT. Thus, clinically relevant
immunity against mucosal toxin challenge can be achieved via the transcutaneous
route.
PMID- 9759834
TI - Detection of a high frequency of virus-specific CD4+ T cells during acute
infection with lymphocytic choriomeningitis virus.
AB - Lymphocytic choriomeningitis virus (LCMV), like many viruses, induces a profound
activation and expansion of CD8+ T cells. In contrast, CD4+ T cells do not
increase in total number during the acute infection. We show here that mice
infected with LCMV have a low but detectable frequency (<1/300) of CD4+ T cells,
as detected by IL-2 production in limiting dilution assays, to each of two class
II peptides during the peak of the acute LCMV response and into long-term memory.
However, during the peak of the acute CD4+ T cell response, >20% of the CD4+ T
cells secreted IFN-gamma after stimulation with PMA and ionomycin, and >10% of
the CD4+ T cells secreted IFN-gamma after stimulation with the LCMV peptides.
Thus, these new sensitive assays reveal a heretofore unappreciated, yet profound
Ag-specific CD4+ T cell response during viral infections.
PMID- 9759835
TI - Cytokines regulate expression and function of the HIV coreceptor CXCR4 on human
mature dendritic cells.
AB - HIV-infected dendritic cells (DC) efficiently transmit infection to CD4+ T cells
during the process of T cell activation. To further understand interactions
between DC and HIV, cytokine regulation of HIV coreceptors on cultured Langerhans
cells (cLC, as prototypes of mature DC) was studied. Expression of cell surface
CXCR4 on cLC was up-regulated by IL-4 and TGF-beta1 and inhibited by IFN-alpha,
IFN-beta, and IFN-gamma, whereas cytokines did not appreciably regulate CCR5.
Changes in cell surface CXCR4 expression on cLC correlated with T cell-tropic
(X4)-HIV envelope-mediated syncytium formation and X4-HIV infection levels. A
relative increase in the ratio of type 2/type 1 cytokine production, which can
occur in HIV disease, may up-regulate CXCR4 expression on mature DC and promote
infection by X4 viruses. Importantly, these findings suggest that cytokine
dysregulation may be linked to the emergence of X4-HIV strains as HIV-infected
individuals progress to AIDS.
PMID- 9759836
TI - p38 MAPK is required for CD40-induced gene expression and proliferation in B
lymphocytes.
AB - We have investigated the activation of the p38 MAPK pathway in response to CD40
engagement in multiple B cell lines and in human tonsillar B cells to define the
role of p38 MAPK in proliferation, NF-kappaB activation and gene expression.
Cross-linking CD40 rapidly stimulates both p38 MAPK and its downstream effector,
MAPKAPK-2. Inhibition of p38 MAPK activity in vivo with the specific cell
permeable inhibitor, SB203580, under conditions that completely prevented MAPKAPK
2 activation, strongly perturbed CD40-induced tonsillar B cell proliferation
while potentiating the B cell receptor (BCR)-driven proliferative response.
SB203580 also significantly reduced expression of a reporter gene driven by a
minimal promoter containing four NF-kappaB elements, indicating a requirement for
the p38 MAPK pathway in CD40-induced NF-kappaB activation. However, CD40-mediated
NF-kappaB binding was not affected by SB203580, suggesting that NF-kappaB may not
be a direct target for the CD40-induced p38 MAPK pathway. In addition, SB203580
selectively reduced CD40-induced CD54/ICAM-1 expression, whereas CD40-dependent
expression of CD40 and CD95/Fas and four newly defined CD40-responsive genes
cIAP2, TRAF1, TRAF4/CART and DR3 were unaffected. Our observations show that the
p38 MAPK pathway is required for CD40-induced proliferation and that CD40 induces
gene expression via both p38 MAPK-dependent and -independent pathways.
PMID- 9759837
TI - Urocanic acid enhances IL-10 production in activated CD4+ T cells.
AB - The immunosuppressive effects of UV radiation have been well documented. This
suppression has been attributed to the action of the cis form of urocanic acid
(UCA), a photoproduct of trans-UCA, a natural constituent of the skin. Here, we
show that mouse spleen cells preincubated with cis-UCA have a diminished
proliferative response to allogeneic cells in MLC and to stimulation with anti
CD3 mAb. Cells preincubated with cis-UCA also had a decreased ability to serve as
APC and to stimulate the proliferation of allogeneic lymphocytes in MLC.
Simultaneously, the production of IL-2 and IFN-gamma by cells preincubated with
cis-UCA was decreased. However, IL-10 gene expression and IL-10 protein secretion
by spleen cells stimulated in the presence of cis-UCA were significantly
enhanced. The principal cell population displaying the cis-UCA-induced elevated
production of IL-10 was CD4+ T cells, which were shown to be a direct target of
cis-UCA action. This was also supported by the observation that production of IL
10 by stimulated splenic non-T cells or by macrophages was not altered by cis
UCA. The enhanced production of IL-10 by activated CD4+ T cells may represent a
novel pathway of UVB radiation-induced, cis-UCA-mediated immunosuppression. We
suggest that the elevated production of IL-10 by activated CD4+ T cells may
account for the suppressor T cell phenomena described in UV-irradiated
recipients.
PMID- 9759838
TI - Identification of a cytoplasmic region of CD20 required for its redistribution to
a detergent-insoluble membrane compartment.
AB - CD20 is a B lymphocyte integral membrane protein with signal-transducing
properties. Abs directed toward extracellular CD20 epitopes activate nonreceptor
tyrosine kinases and modulate cell cycle progression of B lymphocytes. Recently,
we demonstrated that binding of CD20 Abs to B cells induces the rapid
redistribution of up to 95% of CD20 molecules to low density, detergent-insoluble
membrane microdomains and induces the appearance of an approximately 50-kDa
tyrosine-phosphorylated protein in the same compartment. Active relocalization of
CD20 may thus be critical to the initiation of signaling events by CD20. The CD20
cDNA sequence predicts a nonglycosylated protein with four transmembrane-spanning
regions and intracellular amino and carboxyl termini. Here we provide
verification of the location of both the intracellular and extracellular regions
of the CD20 molecule and identify a membrane-proximal sequence in the cytoplasmic
carboxyl tail that is required for CD20 to redistribute to detergent-insoluble
membrane microdomains.
PMID- 9759839
TI - CD148: a receptor-type protein tyrosine phosphatase involved in the regulation of
human T cell activation.
AB - Following ligation of the TCR and costimulatory molecules such as CD28, T cells
proliferate and secrete cytokines. Several other cell surface molecules have been
identified that are capable of augmenting activation mediated via the TCR. These
include CD2, CD27, CD40 ligand, and signaling lymphocytic activation molecule.
Here, we have characterized the expression and function of CD148, a recently
identified receptor-type protein tyrosine phosphatase. CD148 is expressed at low
levels on resting T cells, but is up-regulated following in vitro activation.
Cross-linking CD148 with immobilized anti-CD148 mAb induced vigorous
proliferation of anti-CD3 mAb-activated, highly purified peripheral blood T cells
in an IL-2-dependent, cyclosporin A-sensitive manner. This effect was greatest
after 8 days of in vitro culture, suggesting that this molecule is involved in
the latter stages of a T cell response. CD148-induced proliferation was
significantly greater for CD8+ T cells than for CD4+ T cells. Thus, CD148 is a
receptor-type protein tyrosine phosphatase involved in the activation of T
lymphocytes.
PMID- 9759840
TI - A role for NK cells as regulators of CD4+ T cells in a transfer model of colitis.
AB - Previous studies have shown that the chronic inflammation observed in the colon
of IL-10-deficient (IL-10(-/-)) mice is mediated by CD4+ Th1 T cells and is
dependent on the presence of IFN-gamma for its initial development. As CD4+ T
cells from IL-10(-/-) mice will cause colitis when transferred into recombinase
activating gene (Rag)-deficient recipients, we considered the possibility that
the recipients' NK cells could be an important source of IFN-gamma for the
development of colitis. Therefore, the ability of IL-10(-/-) CD4+ T cells to
cause colitis in Rag-deficient recipients that had been depleted of NK cells was
tested. Contrary to our expectations, NK cell-depleted recipients of IL-10(-/-)
CD4+ T cells developed accelerated disease compared with nondepleted recipients.
Furthermore, CD4+ T cells from normal mice (IL-10(+/+)) also caused colitis in NK
cell-depleted recipient mice, but not in nondepleted recipients. NK cells
inhibited effector CD4+CD45RBhigh T cells, and subsequent experiments showed that
this effect was dependent on perforin. Thus NK cells can play an important role
in down-regulating Thl-mediated colitis by controlling the responses of effector
T cells to gut bacteria.
PMID- 9759841
TI - Chemical chaperones enhance superantigen and conventional antigen presentation by
HLA-DM-deficient as well as HLA-DM-sufficient antigen-presenting cells and
enhance IgG2a production in vivo.
AB - Chemical chaperones, first defined in studies of mutant cystic fibrosis
transmembrane conductance regulator proteins, are small molecules that act as
stabilizers of proteins in their native state and have the ability in some cases
to rescue protein-folding mutants within cells. HLA-DM is an MHC II-specific
molecular chaperone that facilitates peptide loading onto MHC II proteins and
also stabilizes empty MHC II molecules prior to their acquisition of antigenic
peptides. APC that lack HLA-DM exhibit quantitative defects in protein Ag as well
as superantigen presentation. Here we show that both the superantigen and protein
presentation defect in MHC II-transfected, HLA-DM-deficient T2 cells can be
partially overcome by treating the APC with the chemical chaperones glycerol,
DMSO, or trimethylamine oxide. These chemical chaperones also enhance
superantigen and conventional Ag presentation by wild-type APC. In vivo, glycerol
was found to act as an adjuvant and resulted in enhanced IgG2a production to
trinitrophenyl-keyhole limpet hemocyanin (TNP-KLH). In vitro, the enhancement of
Ag presentation by chemical chaperones was found to take place at the level of
the APC and took several hours to develop. Subcellular fractionation experiments
show that HLA-DM enhances presentation of peptides by dense endosome fractions
whereas chemical chaperones enhance presentation by light membrane fractions
(early endosome or plasma membrane). The mechanism by which these chemical
chaperones augment Ag presentation is not defined, but flow cytometric analysis
suggests that the enhancement may be due to a subtle effect on the stability of
several different proteins at the cell surface.
PMID- 9759842
TI - Selective ability of mouse CD1 to present glycolipids: alpha-galactosylceramide
specifically stimulates V alpha 14+ NK T lymphocytes.
AB - Mouse CD1 (mCD1) glycoproteins are known to present peptides, while human CD1
molecules present glycolipids. In mice, mCD1-autoreactive NK T cells play
critical roles in various immune responses, through the secretion of high amounts
of cytokines. This study was initiated to determine whether glycolipids are
involved in the autorecognition of mCD1 by NK T cells. Alpha-galactosylceramide
(alpha-GalCer) was the only glycolipid tested capable of eliciting an mCD1
restricted response by splenic T cells. Moreover, splenic T cells derived from
mCD1-deficient mice were not stimulated by alpha-GalCer, suggesting that the
responsive T cells are selected by mCD1. Using cytoflow techniques, we confirmed
that, in response to alpha-GalCer, IFN-gamma-secreting cells displayed an NK T
cell phenotype. The predominance of IFN-gamma vs IL-4, however, is determined by
the type of mCD1+ APC, suggesting the potential for APC regulation of cytokine
production by NK T cells. Among a panel of 10 mCD1-autoreactive T cell
hybridomas, only the ones that express the typical V alpha 14 J alpha 281 TCR
rearrangement of NK T cells responded to alpha-GalCer. Fixation or treatment of
mCD1+ APCs with an inhibitor of endosomal acidification and the use of mCD1
mutants unable to traffic through endosome still allowed alpha-GalCer to
stimulate NK T cells. Thus, endosomal trafficking and Ag processing are not
required for glycolipid recognition. In summary, alpha-GalCer might be the
autologous ligand, or a mimic of a glycolipid ligand, involved in the mCD1
mediated stimulation of NK T cells.
PMID- 9759843
TI - The tetraspan protein CD82 is a resident of MHC class II compartments where it
associates with HLA-DR, -DM, and -DO molecules.
AB - In specialized APCs, MHC class II molecules are synthesized in the endoplasmic
reticulum and transported through the Golgi apparatus to organelles of the
endocytic pathway collectively called MHC class II compartments (MIICs). There,
the class II-associated invariant chain is degraded, and peptides derived from
internalized Ag bind to empty class II in a reaction that is facilitated by the
class II-like molecule HLA-DM. An mAb raised to highly purified, immunoisolated
MIICs from human B lymphoblastoid cells recognized CD82, a member of the
tetraspan family of integral membrane proteins. Subcellular fractionation,
immunofluorescence microscopy, and immunoelectron microscopy showed that CD82 is
highly enriched in MIICs, particularly in their internal membranes.
Coprecipitation analysis showed that CD82 associates in MIICs with class II, DM,
and HLA-DO (an inhibitor of peptide loading that binds DM). Similar experiments
showed CD63, another tetraspan protein found in MIICs, also associates with these
molecules in the compartment and that CD82 and CD63 associate with each other.
Preclearing experiments demonstrated that both CD82 and CD63 form complexes with
DM-associated class II and DM-associated DO. The ability of CD82 and CD63 to form
complexes with class II, DM, and DO in MIICs suggests that the tetraspan proteins
may play an important role in the late stages of MHC class II maturation.
PMID- 9759844
TI - Superantigen-driven, CD8+ T cell-mediated down-regulation: CD95 (Fas)-dependent
down-regulation of human Ig responses despite CD95-independent killing of
activated B cells.
AB - Staphylococcal superantigens, including staphylococcal enterotoxin B (SEB),
promote vigorous T cell-dependent Ig responses at low dose (0.01 ng/ml). In
contrast, more mitogenic high dose SEB (100 ng/ml) profoundly inhibits the Ig
responses. To assess the contribution of CD8+ T cells to this inhibition, high
dose SEB-dependent killing of activated B cells and down-regulation of Ig
responses were determined. Rapid killing (4 h) of activated B cells was effected
by high dose SEB-activated CD8+ T cells (CD8*), but not by high-dose SEB
activated CD4+ T cells (CD4*), and required the presence of high dose SEB during
the cytotoxicity assay. This killing was abrogated by chelation of extracellular
calcium or by treatment with concanamycin A but was only modestly affected by
treatment with brefeldin A, suggesting a perforin-based pathway of killing.
Despite their widely disparate abilities to rapidly kill activated B cells, CD8*
and CD4* demonstrated similar quantitative abilities to effect high dose SEB
dependent down-regulation of Ig responses. Antagonist anti-CD95 mAb substantially
reversed high dose SEB-dependent downregulation effected by CD8* but had no
appreciable effects on high dose SEB-dependent killing of activated B cells.
These observations strongly suggest that the small fraction of activated B cells
that secrete Ig are selectively sensitive to CD95-based killing but resistant to
CD95-independent killing. This finding may help explain why clinical autoimmunity
associated with increased titers of autoantibodies is a predominant feature of
defects in CD95 or CD95 ligand.
PMID- 9759845
TI - IL-10 is critical in the regulation of autoimmune encephalomyelitis as
demonstrated by studies of IL-10- and IL-4-deficient and transgenic mice.
AB - Experimental autoimmune encephalomyelitis (EAE) and other organ-specific
autoimmune diseases are induced by autoantigen-specific Th1 cells. In contrast,
transfer of autoantigen-reactive Th2 cells that produce IL-4 and IL-10 can
prevent and/or reverse EAE. The relative roles of these two Th2 cytokines in the
regulation of EAE has not been evaluated. Utilizing IL-4 and IL-10 knockout mice
deficient for these cytokines and IL-10 and IL-4 transgenic mice overexpressing
these cytokines, we demonstrate that IL-10-deficient mice (IL-10(-/-)) are more
susceptible and develop a more severe EAE when compared with IL-4-deficient mice
(IL-4(-/-)) or wild-type mice. T cells from IL-10(-/-) mice exhibit a stronger Ag
specific proliferation, produce more proinflammatory cytokines (IFN-gamma and TNF
alpha) when stimulated with an encephalitogenic peptide, and induce very severe
EAE upon transfer into wild-type mice. In contrast, while IL-4 transgenic mice
develop similar disease compared with their nontransgenic littermates, mice
transgenic for IL-10 are completely resistant to the development of EAE. Taken
together, our data suggest that IL-10 plays a more critical role in the
regulation of EAE by regulating autopathogenic Th1 responses.
PMID- 9759846
TI - Expansion by self antigen is necessary for the induction of experimental
autoimmune encephalomyelitis by T cells primed with a cross-reactive
environmental antigen.
AB - Cross-reactivity with environmental antigens has been postulated as a mechanism
responsible for the induction of autoimmune disease. Experimental autoimmune
encephalomyelitis is a T cell-mediated autoimmune disease model inducible in
susceptible strains of laboratory animals by immunization with protein
constituents of myelin. We used myelin proteolipid protein (PLP) peptide 139-151
and its analogues to define motifs to search a protein database for structural
homologues of PLP139-151 and identified five peptides derived from microbial Ags
that elicit immune responses that cross-react with this self peptide. Exposure of
naive SJL mice to the cross-reactive environmental peptides alone was
insufficient to induce autoimmune disease even when animals were treated with Ag
nonspecific stimuli (superantigen or LPS). However, immunization of SJL mice with
suboptimal doses of PLP139-151 after priming with cross-reactive environmental
peptides consistently induced experimental autoimmune encephalomyelitis.
Furthermore, T cell lines from mice immunized with cross-reactive environmental
peptides and restimulated in vitro with PLP139-151 could induce disease upon
transfer into naive recipients. These data suggest that expansion by self Ag is
required to break the threshold to autoimmune disease in animals primed with
cross-reactive peptides.
PMID- 9759847
TI - Neonatal murine B lymphocytes respond to polysaccharide antigens in the presence
of IL-1 and IL-6.
AB - Unlike adults, neonates are unable to respond to polysaccharide Ags, making them
especially vulnerable to pathogenic encapsulated bacteria. Since the Ab response
to polysaccharides in adult mice requires certain cytokines, it was hypothesized
that neonatal murine B cells may be competent to respond to such Ags, but may
fail to do so due to a deficiency of cytokines. Neonatal splenocyte cultures,
which were otherwise unresponsive to trinitrophenyl (TNP)-Ficoll, a haptenated
polysaccharide Ag, mounted an adult-like Ab response when supplemented with IL-1.
However, IL-1 failed to induce such a response to TNP-Ficoll when purified B
cells were used instead. Although IL-6 alone did not induce a response in whole
spleen cells or purified B cells from neonates, it synergized with IL-1 in
inducing purified neonatal B cells to respond to TNP-Ficoll. The avidity of the
cytokine-induced neonatal anti-TNP Abs was comparable to that of Abs made by
adult splenocyte cultures. One effect of IL-1 may be at the level of clonal
expansion, since it induced neonatal B cells to proliferate in response to anti
IgM, which was further enhanced by IL-6. The spontaneous secretion of IL-1 by
neonatal splenocytes was below the detection limit, while adult splenocytes
secreted 30.8 +/- 5.2 U/ml, which is of the same order of magnitude as what was
required to stimulate neonatal B cells to respond to TNP-Ficoll. Thus, the
neonatal unresponsiveness to polysaccharide Ags could be due to the inability of
a non-B cell population resident in the neonatal spleen to secrete sufficient
quantities of IL-1.
PMID- 9759848
TI - CD16 cross-linking blocks rearrangement of the TCR beta locus and development of
alpha beta T cells and induces development of NK cells from thymic progenitors.
AB - Mouse thymocytes normally develop into T lymphocytes, but the embryonic thymus
also contains precursor cells capable of developing into NK cells. Here, we
describe conditions that induce pro-T cells to develop into NK cells. CD16 is
expressed on thymic pro-T cells. We observed that CD16 cross-linking during
culture of embryonic thymic organs suppressed rearrangement of the TCR beta locus
(but did not inhibit TCR gamma locus rearrangement). Rearrangement of the TCR
beta locus is normally required for development to the CD4+CD8+, and this
development was also suppressed by CD16 cross-linking. The ability of CD16 cross
linking to block alpha beta T cell development was not attributable to toxic
effects, but rather was accompanied by promotion of development into NK cells,
identified based on molecular and functional criteria. These results suggest that
common lymphoid precursors can respond to environmental signals to commit to the
alpha beta T vs NK developmental pathways.
PMID- 9759849
TI - Roles of chemokines and receptor polarization in NK-target cell interactions.
AB - We report that the ability of NK cells to produce chemokines is increased in NK
target cell conjugates. The chemokines produced play a critical role in the
polarization and recruitment of NK cells as well as in the NK effector-target
cell conjugate formation. Chemokines induce the formation of two specialized
regions in the NK cell: the advancing front or leading edge, where chemokine
receptors CCR2 and CCR5 cluster, which might guide the cells toward the
chemotactic source, and the uropod, where adhesion molecules ICAM-1 and -3 are
redistributed. NK cell polarity was intrinsically involved in conjugate
formation. The redistribution of both adhesion receptors and CCR was preserved
during the formation of NK-target cell conjugates. Time-lapse videomicroscopy
studies of the formation of effector-target conjugates showed that morphologic
poles are also functionally distinct; while the binding to target cells was
preferentially mediated through the leading edge, the uropod was found at the
rear of migrating NK cells and recruited additional NK cells to the vicinity of
K562 target cells. Inhibition of cell polarization and adhesion receptor
redistribution blocked the formation of NK-K562 cell conjugates and the cytotoxic
activity of NK cells. We discuss the implication of NK-cell polarization in the
development of cytotoxic responses.
PMID- 9759851
TI - Expression and function of CTLA-4 in Th1 and Th2 cells.
AB - CTLA-4 is expressed on T cells after activation and shares homology with the CD28
costimulatory receptor. In contrast to CD28, CTLA-4 is thought to be a negative
regulator of T cell activation. Cross-linking of CTLA-4 during activation of
peripheral T cells reduces IL-2 production and arrests T cells in G1. Much less
is known about the function of CTLA-4 in differentiated T cells. We have
investigated the expression and function of CTLA-4 in established Th1 and Th2
clones and in bulk populations of Th1 and Th2 cells freshly derived in vitro from
TCR transgenic splenocytes. We found that CTLA-4 was induced under similar
conditions and with similar kinetics following activation of both Th1 and Th2
clones. However, CTLA-4 expression was much higher in Th2 than Th1 clones and
lines. This was confirmed by flow cytometry, confocal microscopy, and Northern
blot analysis. The ratio of surface to intracellular expression of CTLA-4 and its
rate of endocytosis were similar in Th1 and Th2 clones. Inhibition of binding of
CTLA-4 to its ligands using soluble anti-CTLA-4 mAb during stimulation with Ag
increased the production not only of IL-2 by Th1 clones, but also that of IL-3
and IFN-gamma by Th1 clones and of IL-3, IL-4, IL-5, and IL-10 by Th2 clones. In
contrast, when anti-CTLA-4 was coimmobilized with anti-CD3 and anti-CD28 mAbs, a
decrease in the production of multiple cytokines was observed. We conclude that
CTLA-4 can function to suppress the production of cytokines produced by both Th1
and Th2 cells.
PMID- 9759850
TI - Generation of biologically active IL-1 beta by matrix metalloproteinases: a novel
caspase-1-independent pathway of IL-1 beta processing.
AB - Biologic activity of IL-1 beta requires processing of the inactive precursor, a
function generally ascribed to IL-1 beta-converting enzyme (caspase-1). However,
alternative mechanisms of IL-1 beta activation have been postulated in local
inflammatory reactions. Expression of IL-1 beta and matrix metalloproteinases
(MMPs) frequently occurs simultaneously at sites of inflammation. We describe
here that stromelysin-1 (MMP-3), as well as the gelatinases A (MMP-2) and B (MMP
9), processes recombinant human IL-1 beta precursor (pIL-1 beta) into
biologically active forms. Detection of both pIL-1 beta processing and biologic
IL-1 beta activity demonstrated different processing capacities of the respective
MMPs. Conversion of pIL-1 beta by stromelysin-1 required coincubation for at
least 1 h, and biologic activity faded after 8 h to 24 h. Gelatinase A was less
effective in processing pIL-1 beta, requiring at least 24 h of coincubation. In
contrast, gelatinase B processed pIL-1 beta within minutes, resulting in
immunoreactive products as well as biologic activity stable for 72 h. In
addition, prolonged incubation of mature IL-1 beta with stromelysin-1, and to a
lesser extent also with gelatinases, but not with interstitial collagenase,
resulted in the degradation of mature IL-1 beta. None of the MMPs processed the
second isoform of IL-1, IL-1 alpha. The present study indicates a biphasic
regulation of IL-1 beta activity by MMPs: a caspase-1-independent pathway of IL-1
beta activation and inhibition of IL-1 beta activity by degrading the mature
cytokine. The balance of the respective MMPs and pIL-1 beta might regulate the
long term appearance of IL-1 beta activity at sites of acute or chronic
inflammation.
PMID- 9759852
TI - Fine specificity of the myelin-reactive T cell repertoire: implications for TCR
antagonism in autoimmunity.
AB - The use of altered peptide ligands (APL) to modulate T cell responses has been
suggested as a means of treating T cell-mediated autoimmune disorders. We have
assessed the therapeutic potential of TCR antagonist peptides in autoimmunity
using murine experimental autoimmune encephalomyelitis (EAE) as a model. The Tg4
transgenic mouse expresses an MHC class II-restricted TCR specific for the
immunodominant encephalitogenic epitope of myelin basic protein, Ac1-9
(acetylated N-terminal nonamer). We have used T cell lines derived from Tg4 mice
to define the TCR contact residues within Ac1-9. APL with appropriate
substitutions at the primary TCR contact residue were effective antagonists of
Tg4 T cells. These antagonist APL, however, were found to induce EAE in
susceptible, nontransgenic strains of mice. Underlying this, the Ac1-9-specific T
cell repertoire of normal mice, rather than reflecting the Tg4 phenotype, showed
considerable diversity in fine specificity and was able to respond to the Tg4
antagonist APL. Defining antagonist APL in vitro using T cell clones, therefore,
was not a reliable approach for the identification of APL with EAE-suppressing
potential in vivo. Our findings highlight the complexities of the autoreactive T
cell repertoire and have major implications for the use of APL in autoimmune
diseases.
PMID- 9759853
TI - Steroid hormone regulation of cytokine secretion by proteolipid protein-specific
CD4+ T cell clones isolated from multiple sclerosis patients and normal control
subjects.
AB - Steroid hormones have long been known to modulate immune function, and recent
studies indicate that one of the means by which they do so involves effects on
the secretion of immunoregulatory cytokines. Our laboratory has found recently
that estradiol (E2) selectively modifies cytokine secretion in proteolipid
protein (PLP)-specific, CD4+ T cell clones isolated from patients with the
demyelinating disease, multiple sclerosis, and from normal control subjects. The
data suggest that E2 may play a role in regulating the balance between pro- and
antiinflammatory conditions, especially at concentrations typical of pregnancy.
To determine whether other pregnancy-associated steroid hormones are capable of
similar activity, we expanded our testing to include estrone (E1), estriol (E3),
progesterone, and dexamethasone. The results indicate that E1 and E3 enhance
secretion of Ag- or anti-CD3-stimulated IL-10 and IFN-gamma in dose-dependent
fashion, almost identical to that of E2. The effect on IL-10 was more potent than
occurred with IFN-gamma. In addition, E1 and E3, like E2, had a biphasic effect
on TNF-alphabeta secretion, with low concentrations stimulatory, and high doses
inhibitory. None of the estrogens influenced IL-4 or TGF-beta secretion.
Progesterone enhanced secretion of IL-4, without affecting any other tested
cytokine. Finally, dexamethasone induced TGF-beta secretion, but inhibited IFN
gamma and TNF-alphabeta. This differential effect of steroid hormones on the
secretion of cytokines by CD4+ human T cell clones is consistent with the
possibility that, collectively, they promote antiinflammatory conditions at high
concentrations typical of pregnancy.
PMID- 9759854
TI - Caspase-independent cell death induced by anti-CD2 or staurosporine in activated
human peripheral T lymphocytes.
AB - We examined the effects of the cell-permeable, broad spectrum peptide caspase
inhibitors, benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD.fmk),
and BOC-Asp(OMe)-fluoromethyl ketone (BOC-D.fmk), on apoptosis induced by anti
CD2, anti-Fas, and the protein kinase inhibitor staurosporine in activated human
peripheral T lymphocytes. We monitored ultrastructural, flow cytometric, and
biochemical apoptotic changes, including externalization of phosphatidylserine,
cleavage of poly(ADP-ribose) polymerase (PARP) and lamins, activation of caspase
3 and caspase-7, decrease in mitochondrial membrane potential, and DNA
fragmentation. Z-VAD.fmk and BOC-D.fmk completely inhibited all the biochemical
and ultrastructural changes of apoptosis in anti-Fas-treated cells. In marked
contrast, neither Z-VAD.fmk nor BOC-D.fmk inhibited CD2- or staurosporine
mediated cell shrinkage, dilatation of the endoplasmic reticulum (seen in anti
CD2-treated cells), externalization of phosphatidylserine, and loss of
mitochondrial membrane potential that accompanied cell death. However, these
inhibitors did inhibit the cleavage of PARP and lamins and the formation of
hypodiploid cells, and partially inhibited chromatin condensation. These results
demonstrate that in activated T cells, anti-CD2 and staurosporine induce a
caspase-independent cell death pathway that exhibits prominent cytoplasmic
features of apoptosis. However, caspase activation is required for the
proteolytic degradation of nuclear substrates such as PARP and lamins together
with the DNA fragmentation and extreme chromatin condensation that occur in
apoptotic cells.
PMID- 9759855
TI - Epidermal growth factor (EGF) modulates fetal thymocyte growth and
differentiation: partial reversal by insulin, mimicking by specific inhibitors of
EGF receptor tyrosine kinase activity, and differential expression of CD45
phosphatase isotypes.
AB - We have recently reported that epidermal growth factor (EGF) modulates thymocyte
development in fetal thymus organ cultures. Exogenously added EGF arrested
thymocyte growth and differentiation, acting at the transition from the CD4-CD8-
(double-negative (DN)) to the CD4+CD8+ (double-positive (DP)) phenotype. In this
study, we further investigate some molecular aspects of this blockade. This
inhibitory effect could be mimicked by tyrphostins, which are selective
inhibitors of EGF receptor kinase activity. An attempt to use insulin (INS) as a
synergizing effector resulted in partial restoration of lobe cellularity, leading
to expansion of the CD44-CD25+ DN subset. However, INS did not overcome the EGF
driven blockade of the thymocyte DN --> DP transition. Analysis of CD45
phosphatase showed that this transition was preceded by a rise in CD45RB isotype
expression. At the end of a 7-day culture, the remaining DN cells from both EGF-
and EGF+INS-treated fetal thymus organ cultures showed a CD45RB- phenotype and
were negative for the EGF-immunoreactive molecule described previously on the
fetal thymocyte surface. This finding implies that neither molecule is related to
the growth capability of cells at this early developmental stage; it is more
likely that the molecules are related to subsequent events in the thymocyte
pathway to the DP phenotype. Thus, our data support the concept that EGF receptor
related circuitry may be relevant in thymus ontogeny. Additionally, evidence is
provided for the duality between growth and differentiation at this particular
early stage of thymocyte development.
PMID- 9759856
TI - Gamma 3 gene-disrupted mice selectively deficient in the dominant IgG subclass
made to bacterial polysaccharides undergo normal isotype switching after
immunization with polysaccharide-protein conjugate vaccines.
AB - Bacterial polysaccharides (PS) are T-independent type 2 Ags that elicit
restricted Ab responses of IgM and IgG3 in mice and IgM and predominantly IgG2 in
humans. Immunodeficiency in the dominant IgG subclass made to PS is associated
with chronic sinus and pulmonary infections with PS-encapsulated bacteria. To
elucidate the biologic role of the dominant IgG subclass in the immune response
to PS and to make an animal model of human IgG subclass deficiency, we generated
mice with a targeted disruption of the exon encoding the CH1 domain of the gamma
3 heavy-chain constant region gene. Homozygotes had no detectable serum IgG3, and
their splenocytes did not produce IgG3 after LPS stimulation. IgG3(-/-) mice
immunized with PS from Pseudomonas aeruginosa LPS O-side chain or Streptococcus
pneumoniae type 19F capsule did not produce any IgG3 anti-PS Abs, in contrast to
wild-type mice in which IgG3 was the major IgG subclass. Immunizing both wild
type and IgG3(-/-) mice with 19F PS-protein conjugate elicited IgG1 Abs. We
conclude that IgG3(-/-) mice have a selective deficiency in the dominant murine
IgG subclass made to T-independent type 2 Ags and may be a useful animal model of
IgG subclass deficiency. In addition, we show that the anti-PS Ab class switching
to IgG1 that occurs when mice are immunized with a PS-protein conjugate vaccine
does not require sequential Ig expression or an intact, upstream gamma 3 heavy
chain gene.
PMID- 9759857
TI - IL-12 up-regulates IL-18 receptor expression on T cells, Th1 cells, and B cells:
synergism with IL-18 for IFN-gamma production.
AB - IL-18 is a product of macrophages and with IL-12 strikingly induces IFN-gamma
production from T, B, and NK cells. Furthermore, IL-18 and 1L-12 synergize for
IFN-gamma production from Th1 cells, although this combination fails to affect
Th2 cells. In this study, we show that IL-12 and IL-18 promptly and
synergistically induce T and B cells to develop into IFN-gamma-producing cells
without engaging their Ag receptors. We also studied the mechanism underlying
differences in IL-18 responsiveness between Th1 and Th2 cells. Pretreatment of T
or B cells with IL-12 rendered them responsive to IL-18, which induces cell
proliferation and IFN-gamma production. These IL-12-stimulated cells had both
high and low affinity IL-18R and an increased IL-18R mRNA expression. In
particular, IL-12-stimulated T cells strongly and continuously expressed IL-18R
mRNA. However, when T cells developed into Th1 cells after stimulation with anti
CD3 and IL-12, they lowered this IL-12-induced-IL-18R mRNA expression. Then, such
T cells showed a dominant response to anti-CD3 by IFN-gamma production when they
were subsequently stimulated with anti-CD3 and IL-18. In contrast, Th2 cells did
not express IL-18R mRNA and failed to produce IFN-gamma in response to anti-CD3
and IL-18, although they produced a substantial amount of IFN-gamma in response
to anti-CD3 and IL-12. However, when Th1 and Th2 cells were stimulated with anti
CD3, IL-12, and IL-18, only the Th1 cells markedly augmented IFN-gamma production
in response to IL-18, suggesting that IL-18 responsiveness between Th1 and Th2
cells resulted from their differential expression of IL-18R.
PMID- 9759858
TI - IL-15 promotes IL-12 production by human monocytes via T cell-dependent contact
and may contribute to IL-12-mediated IFN-gamma secretion by CD4+ T cells in the
absence of TCR ligation.
AB - At inflammatory sites, the number of activated bystander T cells exceeds that of
Ag-activated T cells. We investigated whether IL-15, a monocyte-derived cytokine
that shares several biologic activities with IL-2, may contribute to bystander T
cell activation in the absence of IL-2 and triggering Ag. The addition of IL-15
to cocultures of monocytes and T cells stimulates CD4+ but not CD8+ T cells to
produce IFN-gamma. IFN-gamma production requires endogenous IL-12, the production
of which in turn is dependent upon CD40/CD154 interactions between CD4+ T cells
and monocytes. Indeed, non-TCR-activated CD4+ but not CD8+ T cells express
significant levels of CD154. IL-15 may enhance IFN-gamma in this system by up
regulating CD40 expression on monocytes and IL-12Rbeta1 expression on CD4+ T
cells. Conversely, using neutralizing anti-IL-15 mAb, we show that the ability of
IL-12 to augment IFN-gamma secretion is partly mediated by endogenous IL-15.
Finally, in the absence of monocytes, a synergistic effect between exogenous IL
12 and IL-15 is necessary to induce IFN-gamma production by purified CD4+ T
cells, while IL-15 alone induces T cell proliferation. It is proposed that this
codependence between IL-12 and IL-15 for the activation of inflammatory T cells
may be involved in chronic inflammatory disorders that are dominated by a Th1
response. In such a response, a self-perpetuating cycle of inflammation is set
forth, because IL-15-stimulated CD4+ T cells may activate monocytes to release IL
12 that synergizes with IL-15 to induce IL-12 response and IFN-gamma production.
PMID- 9759859
TI - Impaired TCR-mediated apoptosis and Bcl-XL expression in T cells lacking the
stress kinase activator SEK1/MKK4.
AB - The dual specificity kinase SEK1 (MKK4) is a direct activator of stress-activated
protein kinases (SAPK/JNK) in response to environmental stresses or mitogenic
factors. We show in Sek1(-/-)Rag(-/-) chimeric mice that a Sek1 null mutation
augments the susceptibility of peripheral T cells to TCR/CD3 religation-induced
apoptosis. Sek1(-/-) T cells failed to induce expression of the death suppressor
Bcl-XL in response to Ag receptor activation. The Sek1 mutation did not alter the
induction of apoptosis in response to etoposide, cisplatinum, Adriamycin, and
gamma-irradiation. Moreover, we show that CD3epsilon activation alone leads to
SEK1 activation in Sek1(+/+) T cells. These results suggest that SEK1 transduces
cellular survival signals during T cell stimulation.
PMID- 9759860
TI - Selective inhibitors of cytosolic or secretory phospholipase A2 block TNF-induced
activation of transcription factor nuclear factor-kappa B and expression of ICAM
1.
AB - TNF signaling mechanisms involved in activation of transcription factor NF-kappaB
were studied in the human keratinocyte cell line HaCaT. We show that TNF-induced
activation of NF-kappaB was inhibited by the well-known selective inhibitors of
cytosolic phospholipase A2 (cPLA2): the trifluoromethyl ketone analogue of
arachidonic acid (AACOCF3) and methyl arachidonyl fluorophosphate. The
trifluoromethyl ketone analogue of eicosapentaenoic acid (EPACOCF3) also
suppressed TNF-induced NF-kappaB activation and inhibited in vitro cPLA2 enzyme
activity with a similar potency as AACOCF3. The arachidonyl methyl ketone
analogue (AACOCH3) and the eicosapentanoyl analogue (EPACHOHCF3), which both
failed to inhibit cPLA2 enzyme activity in vitro, had no effect on TNF-induced NF
kappaB activation. TNF-induced NF-kappaB activation was also strongly reduced in
cells stimulated in the presence of the secretory PLA2 (sPLA2) inhibitors 12-epi
scalaradial and LY311727. Addition of excess arachidonic acid suppressed the
inhibitory effect of 12-epi-scalaradial and LY311727. Moreover, both methyl
arachidonyl fluorophosphate and 12-epi-scalaradial blocked TNF-mediated
enhancement of expression of ICAM-1. Activation of NF-kappaB by IL-1beta was
markedly less sensitive to both cPLA2 and sPLA2 inhibitors. The results indicate
that both cPLA2 and sPLA2 may be involved in the TNF signal transduction pathway
leading to nuclear translocation of NF-kappaB and to NF-kappaB-activated gene
expression in HaCaT cells.
PMID- 9759861
TI - Mechanisms of hyaluronan-induced up-regulation of ICAM-1 and VCAM-1 expression by
murine kidney tubular epithelial cells: hyaluronan triggers cell adhesion
molecule expression through a mechanism involving activation of nuclear factor
kappa B and activating protein-1.
AB - The matrix constituent hyaluronan (HA) markedly accumulates in inflammatory
lesions. To gain insight into the biologic significance of this phenomenon we
tested the hypothesis that HA could regulate cell adhesion molecule expression in
epithelial cells. Using a clonal line of mouse cortical tubular (MCT) cells we
found that fragmented intermediate m.w., but not high m.w., HA markedly increased
ICAM-1 and VCAM-1 steady state mRNA and cell surface expression. Up-regulation of
ICAM-1 and VCAM-1 mRNA by HA was preceded by a marked increase in NF-kappaB and
activating protein-1 DNA binding activity in MCT cells. Transcript levels for the
NF-kappaB inhibitor IkappaBalpha and for the activating protein-1 constituents c
jun and c-fos also increased in response to HA stimulation of tubular cells.
Inhibition of NF-kappaB with the serine protease inhibitor N-tosyl-L
phenylalanine chloromethyl ketone blocked the HA-mediated expression of ICAM-1
and VCAM-1 in MCT cells. In conclusion, HA displays proinflammatory effects by
directly stimulating the expression of the cell adhesion molecules ICAM-1 and
VCAM-1 in mouse kidney epithelial cells. HA could thereby play an important role
in leukocyte adhesion in inflammatory renal diseases.
PMID- 9759862
TI - C4d DNA sequences of two infrequent human allotypes (C4A13 and C4B12) and the
presence of signal sequences enhancing recombination.
AB - The DNA sequences of the polymorphic region (C4d) that belong to the infrequent
complement C4 allotypes C4A13 and C4B12 have been obtained. In addition, C4A4 and
C4B2 C4d sequences have been completed. C4A13 shows a new combination of amino
acids at the following polymorphic positions: Asp1054, Pro1101 Cys1102, Leu1105,
Asp1106, Asn1157, Ala1188, and Arg1191. These amino acids conform to the
antigenic determinants Chido 1 and Rodgers 3; thus C4A13 is the only allele
described thus far that carries both Ags. C4A13 and C4A4 carry the motif "ggctc*"
(* means "deletion") at positions 14 to 19 in their intron 28; this motif had
previously been reported only in C4B alleles. The C4B12 nucleotide sequence is
analogous to C4B1b and C4B3 sequences, except for codon 1076, which is GCC in
C4B1b and C4B3 and GGA in C4B12, which is coding for glycine in both cases. A
recombination model for the generation of C4 alleles is formulated based on the
analysis of these new sequences. One recombination would take place between
positions 1157 and 1186 and would give rise to C4A13 and C4B5 or C4A3 (or C4A6)
and C4B2; another one would occur between positions 1054 and 1076 and would
generate C4A3 (or C4A6) and C4B12 or C4A2 and C4Bnew. Analysis of 1157 to 1186
and 1054 to 1076 fragments reveals the presence of putative sequence signals for
recombination (similar to Escherichia coli chi recombination signal); the
accumulation of such signals in fragments 1054 to 1076 supports the notion that a
recombination hot spot for the C4 gene may exist and it also enhances new allele
generation and intraspecies C4 gene homogenization.
PMID- 9759863
TI - Differential usage of VH gene segments is mediated by cis elements.
AB - Ig diversity is generated in large part by the combinatorial joining of the Ig
gene segments, VH, D, and JH, that together encode the variable domain of Ig. The
final Ig repertoire, however, not only reflects the diversity generated through
V(D)J recombinatorial joining, but it is also the product of a number of
developmental restraints and selections. To avoid such restrictions and assess
the recombination potential of individual Ig gene segments, we constructed Ig
heavy (H) chain microlocus plasmids, each of which contain germline coding,
recombination signal, and flanking sequences of a VH, D, and JH gene segment.
These plasmids allow us to assess the recombination potential of the segments in
the context of their natural flanking DNA sequences, but in the absence of any
higher order chromatin structure or cellular selection. We found that the
frequency and extent of deletions and additions at the recombination breakpoints
are similar to those observed at rearranged Ig H chain loci in intact animals.
The relative frequencies of the types of rearrangements--VD-J, V-DJ, VinvD-J
(invD = inverted D), and VDJ--however, differ strongly. Moreover, V81x, the most
used VH gene segment in intact mice, also is overused in this plasmid assay, 15
to 30 times that of another VH segment. This result indicates that the overuse of
V81x in the early B cell repertoire can be a consequence of its DNA sequence and
not of cellular activities.
PMID- 9759864
TI - Carboxyl-terminal 15-amino acid sequence of NFATx1 is possibly created by tissue
specific splicing and is essential for transactivation activity in T cells.
AB - NFAT regulates transcription of a number of cytokine and other immunoregulatory
genes. We have isolated NFATx, which is one of four members of the NFAT family of
transcription factors and is preferentially expressed in the thymus and
peripheral blood leukocytes, and an isoform of NFATx, NFATx1. Here we provide
evidence showing that 15 amino acids in the carboxyl-terminal end of NFATx1 are
required for its maximum transactivation activity in Jurkat T cells. A fusion
between these 15 amino acids and the GAL4 DNA binding domain was capable of
transactivating reporters driven by the GAL4 DNA binding site. Interestingly,
this 15-amino acid transactivation sequence is well conserved in NFAT family
proteins, although the sequences contiguous to the carboxyl-terminal regions of
the NFAT family are much less conserved. We also report three additional isoforms
of NFATx, designated NFATx2, NFATx3, and NFATx4. This transactivation sequence is
altered by tissue-specific alternative splicing in newly isolated NFATx isoforms,
resulting in lower transactivation activity in Jurkat T cells. NFATx1 is
expressed predominantly in the thymus and peripheral blood leukocyte, while the
skeletal muscle expressed primarily NFATx2. In Jurkat cells, transcription from
the NFAT site of the IL-2 promoter is activated strongly by NFATx1 but only
weakly by NFATx2. These data demonstrate that the 15-amino acid sequence of
NFATx1 is a major transactivation sequence required for induction of genes by
NFATx1 in T cells and possibly regulates NFAT activity through tissue-specific
alternative splicing.
PMID- 9759866
TI - Identification of two NF-kappa B sites in mouse CD95 ligand (Fas ligand)
promoter: functional analysis in T cell hybridoma.
AB - Fas ligand (FasL) gene expression is critically involved in peripheral T cell
tolerance and lymphocyte homeostasis. Previous studies have suggested that
nuclear translocation of NF-kappaB during T cell activation is a critical event
for FasL gene activation. In the present study we have identified two NF-kappaB
sites (designated FasL-kappaB1 and FasL-kappaB2) on the promoter (approximately
700 bp) of FasL. The NF-kappaB sites were identified by electrophoretic mobility
shift assay. Transient transfection reporter analyses showed that the FasL
promoter activity was comparable between a construct that contains both sites and
a shorter construct (433 bp) that contains only the FasL-kappaB1 site.
Furthermore, elimination of FasL-kappaB1 by site-directed mutagenesis
significantly inhibited FasL promoter activity. These observations provide strong
evidence that NF-kappaB directly binds to the FasL-kappaB1 site and up-regulates
FasL gene expression.
PMID- 9759865
TI - Role of nuclear factor-kappa B and mitogen-activated protein kinase signaling
pathways in IL-1 beta-mediated induction of alpha-PDGF receptor expression in rat
pulmonary myofibroblasts.
AB - Induction of the alpha-platelet-derived growth factor receptor (PDGF-Ralpha) by
IL-1beta in lung myofibroblasts enhances mitogenic and chemotactic responses to
PDGF, and this could be a mechanism of myofibroblast hyperplasia during lung
fibrogenesis. Since the regulation of many genes by IL-1beta involves activation
of NF-kappaB and mitogen-activated protein (MAP) kinases, we examined these
signaling pathways in the control of PDGF-Ralpha expression by IL-1beta in
cultured rat lung myofibroblasts. Treatment of cells with pyrrolidine
dithiocarbamate (PDTC), an antioxidant that inhibits NF-kappaB activation,
completely blocked PDGF-Ralpha up-regulation by IL-1beta as assayed by [125I]PDGF
AA binding and PDGF-Ralpha mRNA expression, suggesting a role for NF-kappaB.
However, while IL-1beta and TNF-alpha both induced nuclear binding of the Rel
proteins p50 and p65 to an NF-kappaB consensus oligonucleotide in gel shift
assays and caused transient degradation of inhibitor of NF-kappaB-alpha (IkappaB
alpha) in the cytoplasm of myofibroblasts, only IL-1beta upregulated PDGF-Ralpha.
These results suggest that NF-kappaB activation alone is not sufficient for up
regulation of PDGF-Ralpha. An investigation of MAP kinase signaling pathways
revealed that IL-1beta or PDTC activated extracellular signal-regulated kinase-2
(ERK-2) and c-jun NH2 terminal kinase-1 (JNK-1) phosphorylation of PHAS-1 and c
Jun substrates, respectively. Pretreatment of cells with the MAP kinase kinase-1
(MEK1) inhibitor PD 98059 blocked IL-1beta-induced activation of ERK-2 by more
than 90% but enhanced IL-1beta-stimulated induction of PDGF-Ralpha expression
fourfold. Taken together, these data suggest that IL-1beta activates both
positive and negative signaling pathways that control the expression of PDGF
Ralpha. IL-1beta appears to mediate its negative effects on PDGF-Ralpha
expression via MAP kinase activation, while the factor(s) that mediate induction
of PDGF-Ralpha remain to be elucidated.
PMID- 9759867
TI - Molecular mapping with functional antibodies localizes critical sites on the
human IL receptor common gamma (gamma c) chain.
AB - The IL receptor common gamma (gamma c) chain is required for the formation of
high affinity cytokine receptor complexes for IL-2, IL-4, IL-7, IL-9, and IL-15,
and for signals regulating cell survival, growth, and differentiation. Our
current understanding of how gamma c chain associates with multiple ligands and
receptor subunits is drawn largely from its structural homology to the human
growth hormone (hGH) receptor and known structure of the hGH/hGH receptor
complex. These receptors share distinct features in their extracellular portions
and are believed to function by a mechanism of ligand-induced association of
receptor subunits. Here, we report the first directed mutational analysis of the
human gamma c chain by alanine scanning conducted across seven regions likely to
contain residues required for intermolecular contact. Functionally distinct,
neutralizing anti-gamma c mAbs were employed to define critical residues. One
particular mAb, CP.B8, unique in its ability to inhibit IL-2-, IL-4-, IL-7-, and
IL-15-induced proliferation and high affinity cytokine binding of normal T cells
as an intact mAb and as a Fab fragment, localized critical residues to four
noncontinuous stretches, namely residues in loops AB and EF of domain 1, in the
interdomain segment, and in loop FG of domain 2. Notably, these residues form a
contiguous patch on the gamma c chain surface in a three-dimensional structural
model. These results provide functional evidence for the location of contact
points on gamma c chain required for its association with multiple ligands.
PMID- 9759868
TI - Specific antagonism of type I IL-4 receptor with a mutated form of murine IL-4.
AB - IL-4 is a pleiotropic cytokine that is essential for the differentiation of Th2
cells and is critically involved in the pathogenesis of certain infectious and
allergic diseases. We have produced and functionally characterized a mutant of
murine IL-4 (IL-4.Y119D) as a potential antagonist of IL-4. The analysis of IL-4R
binding revealed no differences between wild-type and mutated IL-4. Despite this
finding, IL-4.Y119D was unable to induce proliferation of several IL-4-responsive
T cell lines mediated via the type I IL-4R (IL-4Ralpha/common gamma chain (gamma
c chain)) and specifically inhibited the proliferative effect of wild-type IL-4.
In contrast, with IL-4.Y119D we found induction of MHC class II and CD23
molecules on resting splenic B cells as well as proliferation of B9 plasmocytoma
cells. In addition, IL-4.Y119D induced mRNA for soluble IL-4R, leading to the
release of soluble IL-4R protein by spleen cells. In macrophages, mutated IL-4 in
combination with IFN-gamma induced TNF-alpha-dependent killing of Leishmania
major parasites such as wild-type IL-4. The agonistic effects of IL-4.Y119D were
observed on cells expressing the IL-13R alpha-chain, including an IL-13R alpha
chain transfected T cell line, but were absent in T cells that lack this
molecule, indicating that IL-4.Y119D conveys its activity via the type II IL-4R
(IL-4Ralpha/IL-13Ralpha). The described IL-4 mutant, therefore, represents a new
tool to use in dissecting different IL-4 functions that are mediated by either
type I or type II IL-4R complexes.
PMID- 9759869
TI - Differential transcriptional regulation of CD161 and a novel gene, 197/15a, by IL
2, IL-15, and IL-12 in NK and T cells.
AB - Cytokine-mediated enhancement of spontaneous cytotoxicity depends, at least in
part, on modulation of the expression of surface molecules responsible for
recognition of target cell structures and triggering or inhibition of the
cytotoxic machinery. We previously demonstrated that expression of transcription
factors (e.g., Egr-1, JunB, and c-Fos) is differentially regulated by IL-2 and IL
12. Here we show that expression of CD161/NKR-P1A, a molecule involved in
triggering cytotoxicity, is specifically upregulated by IL-12. CD161
transcription, mRNA accumulation, and surface expression are increased by IL-12.
Other cytokines sharing the IL-2R beta- and/or common gamma-chains (i.e., IL-15,
IL-4, and IL-7) do not mediate these effects. In an effort to analyze the
mechanisms by which IL-2, IL-12, and IL-15 differentially regulate gene
transcription, we have isolated a novel gene, 197/15a, the expression of which in
NK and T cells is down-regulated by IL-2 and IL-15, up-regulated by IL-12, and
not affected by IL-4 and IL-7. IL-2 and IL-15 act, at least in part, repressing
197/15a transcription; their effect on 197/15a mRNA accumulation is partially
independent of novel protein synthesis, likely not mediated by JunB, Bcl-2, or
Bax, and requires the activity of rapamycin-sensitive molecule(s). The
observation that IL-2 and IL-12 differentially modulate CD161 expression suggests
the existence of cytokine-specific mechanisms of modulation of spontaneous
cytotoxicity based on the regulation of expression of surface molecules involved
in target cell recognition and/or triggering of the cytolytic machinery.
PMID- 9759870
TI - The molecular and functional characterization of a dominant minor H antigen, H60.
AB - Minor histocompatibility (H) Ags elicit T cell responses and thereby cause
chronic graft rejection and graft-vs-host disease among MHC identical
individuals. Although numerous independent H loci exist in mice of a given MHC
haplotype, certain H Ags dominate the immune response and are thus of
considerable conceptual and therapeutic importance. To identify these H Ags and
their genes, lacZ-inducible CD8+ T cell hybrids were generated by immunizing
C57BL/6 (B6) mice with MHC identical BALB.B spleen cells. The cDNA clones
encoding the precursor for the antigenic peptide/Kb MHC class I complex were
isolated by expression cloning using the BCZ39.84 T cell as a probe. The cDNAs
defined a new H locus (termed H60), located on mouse chromosome 10, and encoded a
novel protein that contains the naturally processed octapeptide LTFNYRNL (LYL8)
presented by the Kb MHC molecule. Southern blot analysis revealed that the H60
locus was polymorphic among the BALB and the B6 strains. However, none of the H60
transcripts expressed in the donor BALB spleen were detected in the host B6
strain. The expression and immunogenicity of the LYL8/Kb complex in BALB.B and
CXB recombinant inbred strains strongly suggested that the H60 locus may account
for one of the previously described antigenic activity among these strains. The
results establish the source of an immunodominant autosomal minor H Ag that, by
its differential transcription in the donor vs the host strains, provides a novel
peptide/MHC target for host CD8+ T cells.
PMID- 9759871
TI - B cell responses to a peptide epitope. V. Kinetic regulation of repertoire
discrimination and antibody optimization for epitope.
AB - The influence of imposing various conformational constraints on immune responses
to a model epitope within a synthetic peptide immunogen was examined in mice.
Although overall immunogenicity was affected, the model epitope (sequence DPAF)
remained the predominant recognition site regardless of the conformation in which
it was presented. A comparison of anti-DPAF mAbs obtained in response to two
analogue peptides, PS1CT3 and CysCT3, in which the DPAF segment was either
unconstrained or held within a cyclic loop, respectively, revealed a significant
homology in the paratope composition. At one level a subset of anti-PS1CT3 and
anti-CysCT3 mAbs was found to share a common heavy chain variable region. In
addition, nucleotide sequence homology comparisons of both heavy and light chain
variable regions identified the presence of anti-PS1CT3 and anti-CysCT3 mAbs that
collectively appeared to derive from a common progenitor, but with nonidentical
somatic mutations. Interestingly, however, no bias toward homologous Ag could be
discerned on measurement of relative affinities of the mAbs for the two peptides.
In contrast, mAb binding on-rates clearly discriminated between peptides
representing the homologous vs the heterologous confomer of the DPAF epitope.
Thus, it would appear that the kinetics of Ag recognition dominate over
equilibrium binding criteria both in epitope-driven repertoire selection and Ab
maturation in a humoral response.
PMID- 9759872
TI - Characterization of human gamma 4 switch region polymorphisms suggests a meiotic
recombinational hot spot within the Ig locus: influence of S region length on
IgG4 production.
AB - Human gamma4 gene RFLPs, revealed after BamHI digestion, show IGHG4 alleles of
9.0 (9.2), 9.4, and 9.6 kb at various frequencies in different ethnic
populations. Studies in immunodeficient individuals have previously suggested
that the 9.4 BamHI allele is associated with a higher serum level of IgG4 than
the 9.0 (9.2) BamHI allele, but it is not clear whether this is associated with
the S region itself or other control elements. In addition, a duplication of the
9.4-kb gamma4 allele has recently been observed in a high proportion of normal
donors. We therefore undertook a study of the structural basis for the difference
in Ab levels in the various gamma4 alleles. We demonstrate that the Sgamma4
alleles differ in length due to deletions and insertions of a varying number of
79-bp Sgamma4 repeat units. Two novel RFLPs, 8.8 and 9.1 kb, were also observed.
The alleles are likely to be generated by unequal crossing over, and the
breakpoints cluster in Sgamma4 repeat units that contain chi-like motifs,
implicating chi-like sequences in the meiotic recombination. Our data support the
idea that the 9.4-kb BamHI allele is more productive than the 9.0 (9.2)-kb allele
in normal healthy donors, possibly due to the extended switch regions, whereas
duplication of the gamma4 gene has no effect on switching and IgG4 serum levels.
PMID- 9759873
TI - Structural basis of specificity and degeneracy of T cell recognition:
pluriallelic restriction of T cell responses to a peptide antigen involves both
specific and promiscuous interactions between the T cell receptor, peptide, and
HLA-DR.
AB - TCR engagement of peptide-MHC class II ligands involves specific contacts between
the TCR and residues on both the MHC and peptide molecules. We have used
molecular modeling and assays of peptide binding and T cell function to
characterize these interactions for a CD4+ Th1 cell clone, ESL4.34, which
recognizes a peptide epitope of the herpes simplex type 2 virus virion protein,
VP16 393-405, in the context of several HLA-DR alleles. This clone responded to
VP16 393-405 in proliferation and cytotoxicity assays when presented by
DRB1*0402, DRB1*1102, and DRB1*1301, which share a common amino acid sequence,
ILEDE, at residues 67-71 in the alpha-helical portion of the DRbeta polypeptide,
but not when presented by other DR4, DR11, and DR13 alleles that are negative for
this sequence. Using a panel of APCs expressing DR4 molecules that were
mutagenized in vitro at individual residues within this shared epitope and using
peptide analogues with single amino acid substitutions of predicted MHC and TCR
contact residues, a unit of recognition was identified dependent on DRbeta
residues 67-71 and relative position 4 (P4) of the VP16 393-405 peptide. The
interactions of this portion of the peptide-DR ligand with the ESL4.34 TCR
support a structural model for MHC-biased recognition in some Ag-specific and
alloreactive T cell responses and suggest a possible mechanism for autoreactive T
cell selection in rheumatoid arthritis.
PMID- 9759874
TI - Up-regulation by ammonium trichloro(dioxoethylene-0,0') tellurate (AS101) of
Fas/Apo-1 expression on B16 melanoma cells: implications for the antitumor
effects of AS101.
AB - It was recently reported that human and mouse melanoma cells express Fas ligand
(FasL) but almost no Fas, which may contribute to their immune privilege. AS101
(ammonium trichloro(dioxoethylene-0,0')tellurate), a synthetic immunomodulator
with minimal toxicity, was found to have antitumor effects in various tumor
models. Our present study shows that AS101 has direct and indirect effects on
tumor cells; AS101 inhibits the clonogenicity of B16 melanoma cells in vitro.
Moreover, wild-type P53 expression, which is required for induction of Apo-1
expression, increased significantly in AS101-treated cells. We therefore
investigated Fas expression in AS101-treated B16 cells and found that Fas, but
not FasL, expression was significantly increased; moreover, Fas receptors were
functional. Longer incubation with AS101 resulted in spontaneous apoptosis
triggered by the Fas-FasL system. To explore the relationship of these results to
the antitumor effects of AS101, we injected B16-F10 mouse melanoma cells into
syngeneic C57BL/6 mice carrying the lpr mutation in the Fas gene and to gld
mutant mice that lack functional FasL. Tumor development in control groups was
lowest in the lpr mice, while no difference was observed between gld and wild
type mice. Among the AS101-treated groups, the most pronounced effect appeared in
the lpr mice, while the lowest was seen in the gld mutant mice. Our study
suggests that AS101 may render melanoma tumor cells more sensitive to Fas/FasL
induced apoptosis and may therefore have clinical potential.
PMID- 9759875
TI - IFN-gamma is required for IL-12 responsiveness in mice with Candida albicans
infection.
AB - To elucidate the role of IFN-gamma in antifungal CD4+ Th-dependent immunity,
129/Sv/Ev mice deficient for IFN-gamma receptor (IFN-gammaR(-/-)) were assessed
for susceptibility to gastrointestinal or systemic Candida albicans infection and
for parameters of innate and adaptive T helper immunity. IFN-gammaR(-/-) mice
failed to mount protective Th1-mediated acquired immunity upon mucosal
immunization or in response to a live vaccine strain of the yeast. The impaired
Th1-mediated resistance correlated with defective IL-12 responsiveness, but not
IL-12 production, and occurred in the presence of an increased innate antifungal
resistance. The development of nonprotective Th2 responses was observed in IFN
gammaR(-/-) mice upon mucosal infection and subsequent reinfection. However,
under experimental conditions of Th2 cell activation, the occurrence of Th2 cell
responses was similar in IFN-gammaR(-/-) and in IFN-gammaR(+/+) mice. These
results indicate the complex immunoregulatory role of IFN-gamma in the induction
of mucosal and nonmucosal anticandidal Th cell responses; IFN-gamma is not
essential for the occurrence of Th2 responses but is required for development of
IL-12-dependent protective Th1-dependent immunity.
PMID- 9759876
TI - lck-independent inhibition of T cell antigen response by the HIV gp120.
AB - Binding of the HIV envelope glycoprotein gp120 to CD4 inhibits T cell activation.
We have used a murine T cell clone transfected with either wild-type human CD4 or
mutated forms of CD4 to characterize the pathways involved in this inhibitory
effect of gp120. Ag-induced proliferation of T cell clones transfected with human
CD4 was completely inhibited in the presence of gp120, even though stimulation of
this clone is independent of a CD4/MHC class II interaction. In addition, our
results demonstrate that the inhibition by gp120 is not due to the sequestration
of lck from TCR and does not require activation of lck by gp120. This suggests
that CD4 can regulate the initiation of T cell activation independently of its
interaction with lck. Moreover, we demonstrate that the nonresponsiveness induced
by gp120 can be reversed by soluble CD4 when added early after onset of
stimulation and that gp120 exerts its inhibitory effect when cells are in the G0
> or = 1 phase of the cell cycle.
PMID- 9759877
TI - Monoclonal antibodies reveal additional epitopes of serotype D Cryptococcus
neoformans capsular glucuronoxylomannan that elicit protective antibodies.
AB - Epitope specificity and isotype influence mAb efficacy against Cryptococcus
neoformans; however, the relative contribution of each attribute is poorly
understood. To date, only mAbs that recognize two epitopes of capsular
glucuronoxylomannan (GXM), defined by the IgG1 mAbs 2H1 and E1, consistently
mediate protection against C. neoformans. The role of epitope specificity was
further examined using six additional IgG1 mAbs and serotype D C. neoformans ATCC
24067. mAbs 3C2, 439, and 471 recognize the 2H1 epitope, whereas mAbs 339, 1255,
and 302 recognize two separate epitopes. mAbs 3C2, 439, and 471 competed for GXM
with the IgA mAb 18G9, a 2H1 mAb family member, whereas mAbs 302, 339, and 1255
did not. Each mAb bound GXM similarly, as determined by agglutination, direct Ag
binding, Ag inhibition, and indirect capsular immunofluorescence assays. mAb
apparent affinity constants for GXM ranged from 5 to 26 x 10(7) M(-1) with mAb
1255 > 3C2 > 339 > 439 > 471 > 302. Each mAb significantly prolonged survival (p
< 0.05); the average survival times of control and mice passively immunized with
mAbs 3C2, 302, 339, 439, 471, and 1255 were 10.8, 36.6, 33, 25.5, 24.9, 17, and
22.6 days, respectively. Although each mAb enhanced J774.16 cell fungicidal
activity, differences were observed in the ability of each mAb to facilitate
attachment and ingestion of cryptococci. These results indicate 1) two additional
epitope specificities associated with mAb efficacy, 2) differences in opsonic and
protective efficacy for IgG1 anti-GXM mAbs, 3) an association between affinity
and protective efficacy, and 4) additional support for association between an
annular indirect capsular immunofluorescence pattern and mAb efficacy.
PMID- 9759878
TI - Oxidant stress incites spreading of macrophages via extracellular signal
regulated kinases and p38 mitogen-activated protein kinase.
AB - Cultured macrophages exhibit spreading in response to external stimuli. It is
relevant to in vivo morphologic changes of macrophages during extravasation,
migration, and differentiation. The present study was performed to elucidate
molecular mechanisms that regulate spreading of macrophages. Redox is a crucial
factor that modulates a wide range of cell function. We found that macrophages
undergo spreading in response to oxidant stress caused by hydrogen peroxide or an
oxidant generating agent menadione. To identify signaling pathways involved, a
role of mitogen-activated protein (MAP) kinases was investigated. Western blot
analysis showed that treatment of macrophages with menadione rapidly induced
phosphorylation of extracellular signal-regulated kinases (ERK1, ERK2) and p38
MAP kinase, but not c-Jun N-terminal kinase (JNK). Pharmacologic inhibition of
either ERK or p38 activation blunted the macrophage spreading. Similarly,
transfection with dominant-negative mutants of ERKs or a mutant p38 significantly
suppressed the oxidant-triggered spreading. ERKs and p38 are known to activate
serum response element (SRE) via phosphorylation of the ternary complex factor
Elk-1. To further identify downstream events, we focused on a role of SRE.
Stimulation of macrophages with menadione induced activation of SRE. Intervention
in the SRE activation by a dominant-negative mutant of Elk-1 inhibited the
menadione-induced spreading. These results suggest that oxygen radical
metabolites, the well-known mediators for tissue injury, incite spreading of
macrophages via the MAP kinase-SRE signaling pathways.
PMID- 9759879
TI - In vivo and in vitro activities of the gp130-stimulating designer cytokine Hyper
IL-6.
AB - IL-6 is a multifactorial cytokine mediating acute inflammatory responses in the
liver. When IL-6 binds to a specific receptor (IL-6R), the IL-6/IL-6R complex
associates with the signal transducer gp130, initiating intracellular signaling.
A soluble form of the IL-6R (sIL-6R) renders target cells sensitive to IL-6 that
do not express the IL-6R on their surfaces. A designer cytokine, termed Hyper-IL
6, consisting of IL-6 covalently linked to the sIL-6R was fully active on gp130
expressing cells at 100- to 1000-fold lower concentrations than unlinked IL-6 and
IL-6R. Mice were injected i.p. with Hyper-IL-6 or IL-6. Upon injection of Hyper
IL-6 into mice, the acute phase response, as measured by haptoglobin mRNA
expression in the liver, was markedly increased and lasted significantly longer
compared with that in mice injected with a 10-fold higher dose of IL-6 alone. On
human hepatoma cells, Hyper-IL-6 caused similar effects, indicating that the
longer lasting response to the fusion protein could not only be explained by the
longer plasma half-life of the fusion protein. Experiments using iodinated IL-6
and Hyper-IL-6 revealed that Hyper-IL-6 bound with high affinity to gp130 and was
less efficiently internalized. This effect might explain the longer lasting
activity of this protein on cells. The highly active IL-6/sIL-6R designer protein
might be of significant clinical importance for the stimulation of cells that are
more responsive to the IL-6/sIL-6R complex than to IL-6 alone. Such cells include
hemopoietic progenitor cells and hepatocytes.
PMID- 9759880
TI - Down-regulation of CD1 on antigen-presenting cells by infection with
Mycobacterium tuberculosis.
AB - Intracellular pathogens have developed efficient evasion strategies to survive
the defenses of the host immune system. In this study, we describe a new escape
mechanism utilized by Mycobacterium tuberculosis that involves the down
regulation of the Ag-presenting molecule CD1 from the cell surface of CD1+ APCs.
The loss of CD1 from the cell surface is associated with a complete inhibition of
the ability of the infected cells to present Ag to CD1-restricted T cells. The
down-regulation of Ag-presenting molecules on CD1+ APC by infection with M.
tuberculosis is unique for CD1, since the expression of the classical Ag
presenting molecules MHC class I and MHC class II is not influenced. Our data
show that efficient down-regulation of CD1 requires infection of the cells with
live mycobacteria, since heat killing of the bacteria completely abrogates the
effect. The observed down-regulation is not due to the secretion of cytokines or
other host- or pathogen-derived factors. Investigation of upstream events
responsible for the down-regulation of CD1 revealed that infection with live M.
tuberculosis decreased the steady state CD1-mRNA levels. This study introduces a
novel evasion mechanism of M. tuberculosis that could contribute to persistence
of intracellular infection by avoiding immune recognition.
PMID- 9759881
TI - Characterization of a peptide analog of a determinant of type II collagen that
suppresses collagen-induced arthritis.
AB - Immunization of susceptible strains of mice with type II collagen (CII) elicits
an autoimmune arthritis known as collagen-induced arthritis (CIA). One analogue
peptide of the immunodominant T cell determinant, A9 (CII245-270 (I260-->A, A261-
>B, F263-->N)), was previously shown to induce a profound suppression of CIA when
coadministered at the time of immunization with CII. In the present study, A9
peptide was administered i.p., orally, intranasally, or i.v. 2 to 4 wk following
CII immunization. We found that arthritis was significantly suppressed even when
A9 was administered after disease was induced. To determine the mechanism of
action of A9, cytokine responses to A9 and wild-type peptide A2 by CII-sensitized
spleen cells were compared. An increase in IL-4 and IL-10, but not in IFN-gamma,
was found in A9 culture supernatants. Additionally, cells obtained from A9
immunized mice produced higher amounts of IL-4 and IL-10 when cultured with CII
compared with cells obtained from mice immunized with A2, which produced
predominantly IFN-gamma. Suppression of arthritis could be transferred to naive
mice using A9-immune splenocytes. Lastly, phosphorylation of TCRzeta was not
altered in the immunoprecipitates from the lysates of cells exposed to analogue
peptides (A9 and A10) together with wild-type A2 in a T cell line and two I-Aq
restricted, CII-specific T hybridomas. We conclude that analogue peptide A9 is
effective in suppressing established CIA by inducing T cells to produce a Th2
cytokine pattern in response to CII.
PMID- 9759882
TI - A breast and melanoma-shared tumor antigen: T cell responses to antigenic
peptides translated from different open reading frames.
AB - Infusion of TIL586 along with IL-2 into the autologous patient with metastatic
melanoma resulted in the objective regression of tumor. Here, we report that
screening a cDNA library from the 586mel cell line using CTL clones derived from
TIL586 resulted in the isolation of a gene, CAG-3 (cancer Ag gene 3). Sequence
analysis revealed that CAG-3 encodes an open reading frame identical to NY-ESO-1,
which was recently reported to be recognized by autologous serum from a patient
with esophageal cancer. Thus, NY-ESO-1 appears to be an immune target for both Ab
and T cell-mediated responses. Significantly, NY-ESO-1-specific CTL clones were
capable of recognizing two HLA-A31-positive fresh and cultured breast tumors. To
our knowledge, this represents the first direct demonstration that tumor-specific
CTL clones can recognize both breast and melanoma tumor cells. A 10-mer antigenic
peptide ESO10-53 (ASGPGGGAPR) was identified from the normal open reading frame
of NY-ESO-1 based on its ability to sensitize HLA-A31-positive target cells for
cytokine release and specific lysis. Interestingly, two additional CTL clones
that were sensitized with NY-ESO-1 recognized two overlapping antigenic peptides
derived from an alternative open reading frame of the same gene. These findings
indicate that CTLs simultaneously responded to two different gene products
translated from the normal and alternative reading frames of the same gene.
Understanding of this mechanism by which the alternative reading frame is
translated may have important implications in tumor immunology.
PMID- 9759884
TI - Controlled lipidation and encapsulation of peptides as a useful approach to
mucosal immunizations.
AB - To generate a useful strategy for mucosal immunization, we have developed an
approach of lipidating a multiple Ag peptide (MAP) containing part of the V3 loop
from HIV-1 gp120IIIB. In this work, we compare two delivery systems, lipidated
MAP in PBS and encapsulation in poly(DL-lactide-co-glycolide) microparticles.
Subcutaneous immunization, followed by intragastric administration of MAP peptide
entrapped or not entrapped in microparticles, induced mucosal and systemic immune
responses at local and distant sites, including mucosal IgA in saliva, vaginal
secretions and feces, and IgG in blood. However, lipidated Ag delivered in
microparticles induced higher levels of mucosal Abs, particularly of intestinal
IgA, and generated CTL responses. In contrast, lipidated MAP delivered by nasal
route microparticles was less effective in inducing CTL responses. These results
demonstrate the feasibility of using a lipidated multimeric peptide for mucosal
immunization to stimulate both systemic and mucosal immune systems, including the
genital tract, irrespective of the route or method of delivery and without
requiring the use of a carrier or an extraneous adjuvant.
PMID- 9759883
TI - A synthetic lipopolysaccharide-binding peptide based on amino acids 27-39 of
serum amyloid P component inhibits lipopolysaccharide-induced responses in human
blood.
AB - LPS-binding proteins in plasma play an important role in modifying LPS toxicity.
Significant properties have already been attributed to the LPS-binding protein
(LBP). It accelerates LPS toxicity as well as incorporation into high-density
lipoproteins, leading to neutralization of LPS in serum. A search for other LPS
binding components in serum, using LPS-coated magnetic beads, revealed a new LPS
binding protein. N-terminal microsequencing identified this protein as serum
amyloid P component (SAP). Purified SAP bound to smooth and rough types of LPS
via the lipid A part. SAP inhibited the binding of FITC-labeled ReLPS (LPS from
Salmonella minnesota strain R595) to human monocytes and the ReLPS-induced
priming of the oxidative burst of human neutrophils only in the presence of low
concentrations of LBP. In search for the LPS binding site of SAP, we found that
pep27-39, a 13-mer peptide consisting of amino acids 27-39 of SAP, competitively
inhibited the binding of LPS to SAP. In addition, pep27-39 significantly
inhibited ReLPS-induced responses in phagocytes in the presence of serum, as well
as in human whole blood. Carboxamidomethylated pep27-39 showed an even more
pronounced reduction of the ReLPS-induced priming of phagocytes in human blood.
Performing gel filtration of FITC-labeled ReLPS incubated with soluble CD14, we
showed that SAP could not prevent binding of LPS to soluble CD14, in contrast to
pep27-39. The ability of pep27-39 to antagonize specifically the effects of LPS
in the complex environment of human blood suggests that pep27-39 may be a novel
therapeutic agent in the treatment of gram-negative sepsis.
PMID- 9759886
TI - Inhibition of leukocyte emigration induced during the systemic inflammatory
reaction in vivo is not due to IL-8.
AB - In keeping with the multistep model of leukocyte-endothelial cell interaction,
stimulation of endothelium by cytokines or endotoxin (LPS) in vitro leads to
selectin/integrin-mediated neutrophil adhesion, followed by neutrophil
endothelial transmigration. The i.p. injection of LPS in vivo induces a systemic
inflammatory reaction in a mouse model with generalized activation of both
endothelial cells (up-regulation of adhesion molecules ICAM-1, VCAM-1, E
selectin) and neutrophils (up-regulation of Mac-1). However, no intravascular
endothelial adhesion or tissue emigration of neutrophils can be observed. Even
more importantly, the in vivo emigration of polymorphonuclear cells at sites of a
local inflammatory reaction (IL-8, TNF, LPS) is totally inhibited when the mice
are pretreated systemically with LPS, although the neutrophils respond fully to a
rechallenge with LPS ex vivo, and endothelial adhesion molecules are further up
regulated locally. The systemic application of TNF also caused a total inhibition
of neutrophil emigration. However, while anti-TNF mAb abrogated the inhibitory
activity induced by TNF, they had no effect on systemic LPS. The systemic
application of IL-8 did not inhibit neutrophil emigration, nor did the
pretreatment of mice with anti-IL-8 mAb before the systemic application of LPS
abrogate the inhibitory activity induced by LPS. Therefore, the putative
inhibitor of neutrophil emigration, which may be of great physiologic importance,
as it prevents in vivo the generalized emigration of activated neutrophils, most
likely is not IL-8.
PMID- 9759885
TI - Stem cell factor augments Fc epsilon RI-mediated TNF-alpha production and
stimulates MAP kinases via a different pathway in MC/9 mast cells.
AB - Mast cells express the receptor tyrosine kinase kit/stem cell factor receptor
(SCFR) which is encoded by the proto-oncogene c-kit. Ligation of SCFR induces its
dimerization and activation of its intrinsic tyrosine kinase activity leading to
activation of Raf-1, phospholipases, phosphatidylinositol 3-kinase, and
extracellular signal-regulated kinases. However, little is known about the
downstream signals initiated by SCFR ligation except for activation of
extracellular signal-regulated kinases. The murine mast cell line, MC/9,
synthesizes and secretes TNF-alpha following the aggregation of high affinity Fc
receptors for IgE (Fc epsilonRI). Ligation of SCFR or Fc epsilonRI on MC/9 cells
resulted in the activation of all three MAP kinase family members, extracellular
signal-regulated kinases, c-Jun amino-terminal kinase (JNK), and p38. Stem cell
factor (SCF)-induced activation of JNK and p38 was insensitive to wortmannin,
cyclosporin A, and FK506 whereas activation of these kinases through Fc epsilonRI
was sensitive to these drugs. Coligation of SCFR augmented Fc epsilonRI-mediated
activation of MAP kinases, especially JNK activation, and SCF augmented Fc
epsilonRI-mediated TNF-alpha production in MC/9 cells, although SCF alone did not
induce TNF-alpha production. This augmentation by SCF was regulated at the level
of transcription, at least in part, since the promoter activity of TNF-alpha was
enhanced following addition of SCF. These results demonstrate that SCF can
augment Fc epsilonRI-mediated JNK activation and cytokine gene transcription but
via pathways that are regulated differently than the ones activated through Fc
epsilonRI.
PMID- 9759887
TI - Protection from collagen-induced arthritis in granulocyte-macrophage colony
stimulating factor-deficient mice.
AB - The involvement of granulocyte-macrophage CSF (GM-CSF) in collagen-induced
arthritis (CIA) was examined using GM-CSF-deficient mice. Although CIA is
generally considered to be restricted to mice of the H-2q or H-2r haplotypes, we
examined the role of GM-CSF in the CIA model using GM-CSF-deficient (-/-) and
wild-type (+/+) mice on a C57BL/6 (H-2b) background. Mice were immunized by
intradermal injection at the base of the tail with chick type II collagen
followed by a repeat injection 21 days later. We found, based on both clinical
and histologic assessments, that wild-type mice on this background developed
severe CIA, while the GM-CSF-deficient mice had virtually no disease. Mice that
were heterozygous for the GM-CSF gene (+/-) collectively displayed an
intermediate response between those of the GM-CSF(+/+) and GM-CSF(-/-) groups,
suggesting a gene dosage effect. GM-CSF(+/+) and GM-CSF(+/-) mice exhibited CIA
responses ranging from mild (single digits) to severe swelling of all four paws,
while in the few GM-CSF(-/-) mice that developed CIA the disease was confined to
single digits. Despite the putative role of GM-CSF in dendritic cell development,
GM-CSF-deficient mice exhibited both humoral and cellular (delayed-type
hypersensitivity) responses to type II collagen; however, the cellular response
was significantly reduced in the GM-CSF-deficient mice compared with the wild
type controls. These findings suggest that GM-CSF is required for CIA development
in mice and support the idea that GM-CSF is a key cytokine in inflammatory joint
disease.
PMID- 9759888
TI - Dust mite proteolytic allergens induce cytokine release from cultured airway
epithelium.
AB - Endogenous proteolytic enzymes have been shown to be potential sources of airway
inflammation inducing proinflammatory cytokine release from respiratory
epithelial cells; however, whether any of the exogenous proteases from important
allergen sources such as the house dust mite present in our environment behave in
a similar fashion is unclear. To this end, we have investigated whether the mite
cysteine and serine proteolytic allergens, Der p 1 and Der p 9, respectively,
induced cytokine production from primary human bronchial epithelial cells and
from the epithelial cell line BEAS-2B. Cells were exposed to mite proteases, and
cells or supernatants were assayed for cytokine release, cytokine mRNA
expression, and modulation of intracellular calcium ion concentration. Both
proteases induced concentration- and time-dependent increases in the release of
granulocyte-macrophage (GM)-CSF, IL-6, and IL-8 as well as an increase in the
expression of IL-6 mRNA. Cytokine release and mRNA expression were first observed
at 8 h and 2 h after protease exposure, respectively. The minimum concentration
of each protease that was required to stimulate GM-CSF, IL-6, and IL-8 release
was approximately 10 ng/ml. Cytokine release was initiated by 1 to 2 h of
protease exposure, although maximum concentrations were detected only after a 24
h incubation. IL-6, but not IL-8 and GM-CSF, was shown to be degraded by both
proteases at concentrations of > 2 microg/ml. The proteases also stimulated
changes in the intracellular calcium ion concentration. All mite protease-induced
phenomena were inhibited using appropriate protease inhibitors. These results
suggest that the proteolytic activity of an allergen may stimulate the release of
proinflammatory cytokines from human bronchial epithelium.
PMID- 9759889
TI - Stromal cell-derived factor-1 alpha and stem cell factor/kit ligand share
signaling pathways in hemopoietic progenitors: a potential mechanism for
cooperative induction of chemotaxis.
AB - Stromal cell-derived factor (SDF-1alpha), the ligand for CXCR4, is a chemokine
that acts as a potent chemoattractant for hemopoietic progenitor cells. Stem cell
factor/kit ligand (SCF/KL), an early acting cytokine, has recently been reported
to enhance the chemotaxis induced by SDF-1alpha. However, very little is known
about downstream signaling events following these receptor-ligand interactions.
To investigate these events, we utilized a model progenitor cell line, CTS, which
expresses both the CXCR4 and c-kit receptors. We observed strong Ca2+
mobilization and enhancement of chemotaxis following treatment with SDF-1alpha or
SCF/KL. A combination of these factors enhanced this chemotaxis in CTS cells as
well as in CD34+ bone marrow cells. Prior treatment of CTS cells with pertussis
toxin inhibited the SDF-1alpha-induced chemotaxis, suggesting that SDF-1alpha
signaling involves a pertussis-sensitive Gi-coupled protein. SDF-1alpha treatment
resulted in a rapid phosphorylation of the focal adhesion molecules RAFTK
(related adhesion focal tyrosine kinase), paxillin, and p130cas, which then
declined within minutes. SCF/KL alone or in combination with SDF-1alpha induced a
rapid and sustained effect on phosphorylation of these substrates. SDF-1alpha
treatment resulted in a rapid and robust activation of p44/42 mitogen-activated
protein kinase compared with the relatively weak and delayed effect of SCF/KL
treatment. Interestingly, a delayed but sustained activation of mitogen-activated
protein kinase activation was observed when the factors were used in combination.
Such cooperativity in downstream signaling pathways may explain the enhanced
chemotaxis of progenitors observed with SDF-1alpha in combination with SCF/KL.
PMID- 9759890
TI - Lipopolysaccharide-induced desensitization of junB gene expression in a mouse
macrophage-like cell line, P388D1.
AB - Treatment of a mouse macrophage cell line, P388D1, for 1 h with bacterial LPS
caused a transient increase in the level of junB mRNA expression. These cells
became refractory in terms of the junB gene response to exposure to a second
round of LPS or lipid A, but not to PMA. The LPS-induced desensitized state was
not due to the shortening of the half-life of junB mRNA, but was suggested, by
nuclear run-on analysis, to be caused by reduction of junB gene transcription.
Pretreating cells with herbimycin A, a tyrosine kinase inhibitor, substantially
inhibited LPS-induced expression of junB mRNA and decreased tyrosine
phosphorylation of 38- to 42-kDa proteins, which comigrated with p38 and p42
mitogen-activated protein (MAP) kinases. Parallel to down-regulation of junB mRNA
expression, activation of the p38 MAP kinase was markedly reduced in LPS-tolerant
cells, whereas activation of p42 MAP kinase was relatively constant. The specific
p38 MAP kinase inhibitor, SB202190, potently inhibited LPS-induced junB mRNA
expression. These results suggest that the LPS-induced desensitization of junB
gene expression occurs at or upstream of the level of gene transcription and may
be involved in a defective LPS-induced p38 MAP kinase pathway.
PMID- 9759891
TI - Modulation of human neutrophil apoptosis by immune complexes.
AB - In the present study we examined whether immune complexes (IC) are able to
modulate human neutrophil apoptosis. We observed different effects depending on
the type of IC employed. Precipitating IC (pIC) and Ab-coated erythrocytes (E
IgG) triggered a marked stimulation of apoptosis, while heat-aggregated IgG and
soluble IC, significantly delayed spontaneous apoptosis. Blocking Abs directed to
Fcgamma receptor type II (FcgammaRII), but not to FcgammaRIII, markedly
diminished the acceleration of apoptosis triggered by either pIC or E-IgG,
supporting a critical role for FcgammaRII in apoptosis stimulation. This
phenomenon, on the other hand, does not appear to involve IC phagocytosis or the
participation of CR3. Acceleration of neutrophil apoptosis triggered by either
pIC or E-IgG seems to require the activation of the respiratory burst, as
suggested by 1) the ability of catalase to prevent apoptosis stimulation; 2) the
effect of azide, an heme enzyme inhibitor, which dramatically enhanced apoptosis
induced by pIC or E-IgG; and 3) the inability of pIC or E-IgG to accelerate
apoptosis of neutrophils isolated from CGD patients. It is well established that
IC affect the course of inflammation by inducing the release of inflammatory
cytokines, proteolytic enzymes, oxidative agents, and other toxic molecules. Our
results suggest that IC may also affect the course of inflammation by virtue of
their ability to modulate neutrophil apoptosis.
PMID- 9759892
TI - The regulation and functional consequence of proinflammatory cytokine binding on
human intestinal epithelial cells.
AB - Products of an activated immune system may affect cells within the immune system
as well as nonlymphoid cells in the local environment. Given the immunologically
activated state of the intestinal tract, it is conceivable that locally produced
cytokines could regulate epithelial cell function. To assess whether epithelial
cells are targets for particular cytokines, we initiated studies on the binding
of a panel of proinflammatory cytokines in freshly isolated epithelial cells from
normal and inflammatory bowel disease (IBD) patients as well as in cell lines.
Isolated intestinal epithelial cells (IEC) were stained with phycoerythrin
conjugated or biotinylated cytokines to determine the expression and density of
receptors for IL-1beta, IL-6, granulocyte-macrophage CSF (GM-CSF), and TNF-alpha.
Receptors for IL-1beta, IL-6, and GM-CSF were readily detectable in all
epithelial cell preparations at levels equal to (GM-CSFR) or lower than those
seen on monocytes. However TNFalpha-R were not detectable on freshly isolated
IECs. Receptor density was greater in surface vs crypt epithelial cells, but no
significant differences were seen between normal and IBD epithelial cells.
Expression of IL-1R and IL-6R was enhanced by LPS and IFN-gamma. Functionally, IL
1beta enhanced proliferation of the IEC cell line, DLD1, whereas GM-CSF treatment
of de-differentiated crypt-like DLD1 and HT29 cells resulted in enhanced
expression of ICAM-1. Furthermore, TNF-alpha treatment enhanced the secretion of
IL-8 and GRO-alpha in HT29 cells, but not in freshly isolated IEC cultures. The
differential binding and function of proinflammatory cytokines on IEC support the
hypothesis that these cytokines may be involved in normal physiological processes
as well as in regulating mucosal immune responses.
PMID- 9759893
TI - Soluble ICAM-1 activates lung macrophages and enhances lung injury.
AB - Because of the important role of rat ICAM-1 in the development of lung
inflammatory injury, soluble recombinant rat ICAM-1 (sICAM-1) was expressed in
bacteria, and its biologic activities were evaluated. Purified sICAM-1 did bind
to rat alveolar macrophages in a dose-dependent manner and induced production of
TNF-alpha and the CXC chemokine, macrophage inflammatory protein-2 (MIP-2).
Alveolar macrophages exhibited cytokine responses to both sICAM-1 and immobilized
sICAM-1, while rat PBMCs failed to demonstrate similar responses. Exposure of
alveolar macrophages to sICAM-1 resulted in NFkappaB activation (which was
blocked by the presence of the aldehyde peptide inhibitor of 28S proteosome and
by genistein, a tyrosine kinase inhibitor). As expected, cross-linking of CD18 on
macrophages with Ab resulted in generation of TNF-alpha and MIP-2. This response
was also inhibited in the presence of the proteosome inhibitor and by genistein.
Alveolar macrophages showed adherence to immobilized sICAM-1 in a CD18-dependent
manner. Finally, airway instillation of sICAM-1 intensified lung injury produced
by intrapulmonary deposition of IgG immune complexes in a manner associated with
enhanced lung production of TNF-alpha and MIP-2 and increased neutrophil
recruitment. Therefore, through engagement of beta2 integrins, sICAM-1 enhances
alveolar macrophage production of MIP-2 and TNF-alpha, the result of which is
intensified lung injury after intrapulmonary disposition of immune complexes.
PMID- 9759894
TI - Essential roles of Lyn in fibronectin-mediated filamentous actin assembly and
cell motility in mast cells.
AB - Although the requirement for c-Src in extracellular matrix (ECM)-mediated
fibroblast motility has been well established, the roles of hemopoietic Src
family protein tyrosine kinases in leukocyte migration have not been fully
elucidated. To address the issue, we analyzed fibronectin (Fn)-mediated adhesion
signaling in rat basophilic leukemia (RBL) 2H3 cells overexpressing 1) Csk, 2) a
membrane-anchored, gain-of-function Csk (mCsk), and 3) a kinase-defective mCsk
(mCsk(-)). Parent RBL2H3 cells, expressing autoactivated c-kit, readily adhered
to Fn-coated surface, developed typical leukocyte adhesion machinery (podosome),
and migrated toward Fn without cytokine priming, thus provided a simple
experimental system to analyze Fn-mediated outside-in signaling. While
overexpression of Csk or the Csk mutants did not significantly affect cell
adhesion to the Fn surface or alpha5 integrin recruitment to the attachment
sites, Csk suppressed and mCsk almost abolished Fn-mediated tyrosine
phosphorylation of paxillin, filamentous actin assembly to podosomes, and cell
migration, but mCsk(-) did not. Coexpression of LynA devoid of C-terminal
negative regulatory tyrosine in mCsk cells successfully restored Fn-mediated
podosome formation and cell migration. Coexpression of c-Src lacking the C
terminal tyrosine reconstructed podosomes, but could not restore the cell
migration regardless of its expression level. Collectively, these observations
provide evidence that Src family protein tyrosine kinases are required, and that
Lyn could transmit sufficient signal for Fn-mediated cytoskeletal changes leading
to cell locomotion in RBL2H3 cells, and they suggest that Lyn and c-Src are
differentially involved in cell motility.
PMID- 9759895
TI - CXCR4 and CCR5 expression delineates targets for HIV-1 disruption of T cell
differentiation.
AB - HIV-1 disease is often associated with CD4+ T lymphopenia as well as quantitative
reductions in naive CD8+ T cells and cytopenias involving nonlymphoid hemopoietic
lineages. Studies in HIV-1-infected humans as well as in animal models of lenti
virus disease indicate that these effects may be secondary to infection and
destruction of multilineage and lineage-restricted hemopoietic progenitor cells.
To define the stages of T cell differentiation that might be susceptible to HIV
1, we performed flow cytometric analysis of the surface expression of CXCR4 and
CCR5 on T cells and their progenitors from fetal tissue, cord blood, SCID-hu
Thy/Liv mice, and adult peripheral blood. We found that CXCR4 is expressed at low
levels on hemopoietic progenitors in the bone marrow, is highly expressed on
immature (CD3-CD4+CD8-) T cell progenitors in the thymus, and then is down
regulated during thymocyte differentiation. As thymocytes leave the thymus and
enter the peripheral circulation, the expression of CXCR4 is again up-regulated.
In contrast, CCR5 is undetectable on most hemopoietic progenitors in the bone
marrow and on intrathymic T progenitor cells. It is up-regulated when thymocytes
coexpress CD4 and CD8, then down-regulated either in the thymus (CD4+ cells) or
during exit from the thymus (CD8+ cells). These results indicate that discrete,
lineage-related populations of T cell progenitors may vary widely in their
potential to respond to chemokines and to be infected by HIV-1, and that T
lymphoid differentiation is particularly vulnerable to CXCR4-using viruses.
PMID- 9759896
TI - Membrane cofactor protein: importance of N- and O-glycosylation for complement
regulatory function.
AB - Membrane cofactor protein (MCP; CD46) is a type 1 membrane glycoprotein that
inhibits complement activation on host cells. It also is a measles virus (MV)
receptor, an adherence factor for group A Streptococcus pyogenes, and a cellular
pilus receptor for pathogenic Neisseria. The amino terminus of MCP consists of
four complement control protein (CCP) repeats, three of which (CCP-1, -2, and -4)
possess N-glycans. Immediately following the CCP modules is an alternatively
spliced region for extensive O-glycosylation (termed the STP domain). Previous
studies established that the N-glycan of CCP-2 is essential for MV binding and
infection and that the splicing variants of the STP domain not only affect MV
binding and fusion, but also differentially protect against complement-mediated
cytolysis. In this report, we dissect the role of these carbohydrates on
complement regulatory function. We constructed, expressed, and characterized
proteins deleting these carbohydrates. For MCP-mediated protection against
cytolysis, the N-glycans of CCP-2 and -4 were necessary, the STP segment
influenced but was not essential, and the N-glycan of CCP-1 was not required. In
addition, the rate and magnitude of cell surface cleavage of C4b to C4c and C4d
by MCP and factor I correlated with cytoprotection. These studies expand the
structure-function understanding of the active sites of MCP and elucidate an
important role for carbohydrates in its function, a finding consistent with their
conservation in the MCP of other species.
PMID- 9759897
TI - A complex element regulates IFN-gamma-stimulated monocyte chemoattractant protein
1 gene transcription.
AB - Monocyte chemoattractant protein-1 (MCP-1) is induced in chronic osseous
inflammation, and is temporally and spatially correlated with monocyte
recruitment. We investigated the mechanism of MCP-1 regulation in a human
osteoblastic cell line in response to IFN-gamma, a potent mediator of the immune
inflammatory response. Nuclear run-on and stability studies demonstrated that IFN
gamma stimulated MCP-1 transcription and did not enhance mRNA stabilization.
Using MCP-1 promoter/reporter gene constructs, we determined that IFN-gamma
enhanced MCP-1 transcription is regulated by a 29-bp element located at -227
relative to the ATG start codon. This element contains a 13-bp CT-rich sequence
(GCTTCCCTTTCCT) adjacent to a IFN-gamma activation site (GAS). Since deletion of
the CT sequence enhanced both the magnitude and duration of IFN-gamma-stimulated,
GAS-mediated transcription, we have termed it the IFN response-inhibitory
sequence (IRIS). The combined IRIS/GAS sequence is highly conserved in mouse,
rat, and bovine MCP-1 genes. In gel-shift assays, nuclear extracts from IFN-gamma
stimulated osteoblastic cells formed two specific inducible bands with labeled
IRIS/GAS DNA. Both bands were supershifted by anti-STAT1 Abs, but not by Abs to
STAT2, p48(ISGF-3y), IFN-regulatory factor-1, or IFN-regulatory factor-2.
Formation of one of the bands required the presence of the IRIS moiety. IRIS/GAS
DNA also formed a number of specific complexes with constitutively expressed
factors, none of which were affected by the above Abs. These studies establish a
mechanism for IFN-gamma-stimulated MCP-1 expression and identify a complex
element that regulates MCP-1 gene transcription.
PMID- 9759898
TI - A RANTES-antibody fusion protein retains antigen specificity and chemokine
function.
AB - The successful eradication of cancer cells in the setting of minimal residual
disease may require targeting of metastatic tumor deposits that evade the immune
system. We combined the targeting flexibility and specificity of mAbs with the
immune effector function of the chemokine RANTES to target established tumor
deposits. We describe the construction of an Ab fusion molecule with variable
domains directed against the tumor-associated Ag HER2/neu, linked to sequences
encoding the chemokine RANTES (RANTES.her2.IgG3). RANTES is a potent
chemoattractant of T cells, NK cells, monocytes, and dendritic cells, and
expression of RANTES has been shown to enhance immune responses against tumors in
murine models. RANTES.her2.IgG3 fusion protein bound specifically to HER2/neu Ag
expressed on EL4 cells and on SKBR3 breast cancer cells as assayed by flow
cytometry. RANTES.her2.IgG3 could elicit actin polymerization of THP-1 cells and
transendothelial migration of primary T lymphocytes. RANTES.her2.IgG3 prebound to
SKBR3 cells also facilitated migration of T cells. RANTES.her2.IgG3 bound
specifically to the CCR5 chemokine receptor, as demonstrated by flow cytometry,
and inhibited HIV-1 infection via the CCR5 coreceptor. RANTES.her2.IgG3, alone or
in combination with other chemokine or cytokine fusion Abs, may be a suitable
reagent for recruitment and activation of an expanded repertoire of effector
cells to tumor deposits.
PMID- 9759899
TI - Evidence for IL-12-activated Ca2+ and tyrosine signaling pathways in human
neutrophils.
AB - The cytokine IL-12 is proposed to play a bridging role between innate and
adaptive immunity. Here we demonstrate that IL-12 binds specifically to human
neutrophils. This binding leads to a transient increase in 1) intracellular free
calcium due to its release from membrane-enclosed stores and its influx from
extracellular medium, 2) actin polymerization, and 3) tyrosine phosphorylation.
IL-12 treatment also leads to a concentration-dependent increase in reactive
oxygen metabolite production. The effect of IL-12 is blocked by neutralizing Abs
to IL-12. Inhibition of either calcium transient or tyrosine phosphorylation
causes inhibition of reactive oxygen metabolite production. However, inhibition
of actin polymerization enhances IL-12-induced oxidase activation. Our data
suggest 1) a direct role for IL-12 in the activation of human neutrophils, and 2)
a calcium-dependent signaling pathway for IL-12.
PMID- 9759900
TI - Prostaglandin E2 stimulates IL-8 gene expression in human colonic epithelial
cells by a posttranscriptional mechanism.
AB - Intestinal mucosal epithelial cells produce IL-8, a neutrophil chemoattractant
that contributes to mucosal inflammation in various infectious and inflammatory
diseases. However, the mediators involved and the molecular regulation of IL-8
production are poorly understood. As PGE2 is central in gut inflammation and
modulates a variety of mucosal epithelial cell functions, we determined whether
PGE2 can affect the expression of IL-8. Exogenous PGE2 induced the accumulation
of IL-8 mRNA and protein production in a dose- and time-dependent manner in T84
human colonic epithelial cells. Forskolin and dibutyryl cAMP, which increase
intracellular cAMP, stimulated IL-8 in a fashion similar to that of PGE2. PGE2
and PGE2 receptor agonists coupling through EP4 receptors elevated intracellular
cAMP and up-regulated IL-8 mRNA expression by activating protein kinase A. Unlike
PMA, PGE2 and forskolin did not increase IL-8 gene transcription. However, PGE2,
forskolin, and PMA enhanced the stability of IL-8 mRNA transcripts, suggesting
the involvement of posttranscriptional regulation. Chloramphenicol
acetyltransferase reporter gene transfection studies confirmed the presence of a
PGE2 responsive cis-element(s) in the IL-8 3' untranslated region. Furthermore,
dexamethasone inhibited PGE2-, forskolin-, and dibutyryl cAMP-induced, but not
PMA-induced, IL-8 protein production. These results highlight a novel role for
PGE2 in up-regulating IL-8 gene expression by colonic epithelial cells, which may
contribute to exacerbation of inflammation in the gastrointestinal tract.
PMID- 9759901
TI - Poly(ADP-ribose) synthetase activation mediates mitochondrial injury during
oxidant-induced cell death.
AB - Reactive oxidant species are important mediators of tissue injury in shock,
inflammation, and reperfusion injury. The actions of a number of these oxidants
(e.g., hydroxyl radical and peroxynitrite, a reactive oxidant produced by the
reaction of nitric oxide and superoxide) are mediated in part by the activation
of the nuclear nick sensor enzyme, poly(ADP)-ribose synthetase (PARS), with
consequent cellular energy depletion. Here we investigated whether PARS
activation contributes to the mitochondrial alterations in cells exposed to
oxidants. Authentic peroxynitrite (20 microM), the peroxynitrite-generating
compound 3-morpholinosidnonimine, the combination of pyrogallol and S-nitroso-N
acetyl-D,L-penicillamine, as well as hydrogen peroxide induced a time- and dose
dependent decrease in mitochondrial transmembrane potential (delta psi(m)) in
thymocytes, as determined by flow cytometry using the mitochondrial potential
sensitive dyes DiOC6(3) and JC-1. A time- and dose-dependent increase in
secondary reactive oxygen intermediate production and loss of cardiolipin, an
indicator of mitochondrial membrane damage, were also observed, as measured by
flow cytometry using the fluorescent dyes dihydroethidine and nonyl-acridine
orange, respectively. Inhibition of PARS by 3-aminobenzamide or 5-iodo-6-amino
1,2-benzopyrone attenuated peroxynitrite-induced delta psi(m) reduction,
secondary reactive oxygen intermediate generation, cardiolipin degradation, and
intracellular calcium mobilization. Furthermore, thymocytes from PARS-deficient
animals were protected against the peroxynitrite- and hydrogen peroxide-induced
functional and ultrastructural mitochondrial alterations. In conclusion,
mitochondrial perturbations during oxidant-mediated cytotoxicity are, to a
significant degree, related to PARS activation rather than to direct effects of
the oxidants on the mitochondria.
PMID- 9759902
TI - Genetic basis of human complement C8 alpha-gamma deficiency.
AB - Deficiency of the alpha-gamma subunit of the eighth component of complement
(C8alpha-gammaD) is frequently associated with recurrent neisserial infections,
especially meningitis caused by Neisseria meningitidis. We here report the
molecular basis of C8alpha-gammaD in two unrelated Japanese subjects. Screening
all 11 exons of the C8alpha gene and all 7 exons of the C8gamma gene and their
boundaries by exon-specific PCR/single-strand conformation polymorphism
demonstrated aberrant single-stranded DNA fragments in exon 2 of C8alpha gene in
case 1 and in exons 2 and 9 of C8alpha gene in case 2. Nucleotide sequencing of
the amplified DNA fragments in case 1 revealed a homozygous single-point mutation
at the second exon-intron boundary, inactivating the universally conserved 5'
splice site consensus sequence of the second intron (IVS2+1G-->T). Case 2 was a
compound heterozygote for the splice junction mutation, IVS2+1G-->T, and a
nonsense mutation at Arg394 (R394X). R394X was caused by a C to T transition at
nucleotide 1407, the first nucleotide of the codon CGA for Arg394, leading to a
stop codon TGA. No mutations were detected in the C8gamma gene by our method. Our
results indicate that the pathogenesis of C8alpha-gammaD might be caused by
heterogeneous molecular defects in the C8alpha gene.
PMID- 9759903
TI - Immune invasion of the central nervous system parenchyma and experimental
allergic encephalomyelitis, but not leukocyte extravasation from blood, are
prevented in macrophage-depleted mice.
AB - Organ-specific autoimmune diseases are characterized by infiltrates, including T
lymphocytes and activated macrophages. Macrophages and secondarily activated
tissue resident counterparts can both present Ag to and contribute to cytokine
secretion by T lymphocytes. We have previously shown a crucial role of peripheral
macrophages in experimental allergic encephalomyelitis (EAE), a Th1-mediated
demyelinating disease that serves as a an animal model for multiple sclerosis
(MS), by their depletion using mannosylated liposome-encapsulated
dichloromethylene diphosphonate (Cl2MDP). Here we describe studies to investigate
the mechanisms by which macrophages contribute to the lesion formation in EAE, by
studying the effect of Cl2MDP-containing mannosylated liposomes (Cl2MDP-mnL) on
adoptively transferred EAE in SJL/J mice. Adoptive transfer of EAE with myelin
basic protein-reactive CD4+ T cells to SJL/J mice was abrogated by Cl2MDP-mnL
treatment. CD4+ T cell and MHC II+ B220+ B cell extravasation from blood vessels
and Th1 cytokine production were not inhibited. However, invasion of the central
nervous system intraparenchymal tissues by lymphocytes, F4/80+, Mac-1+, and MOMA
1+ macrophages was almost completely blocked after treatment with Cl2MDP-mnL.
Furthermore, in Cl2MDP-mnL-treated mice, the myelin sheaths appeared completely
normal, whereas, in the control groups, marked demyelination occurred. Production
of TNF-alpha and inducible nitric oxide synthase, both associated with
macrophage/microglial activation, was inhibited. This intervention reveals a role
for macrophages in regulating the invasion of autoreactive T cells and secondary
glial recruitment that ordinarily lead to demyelinating pathology in EAE and
multiple sclerosis.
PMID- 9759904
TI - Role of kappa II-A2 light chain CDR-3 junctional residues in human antibody
binding to the Haemophilus influenzae type b polysaccharide.
AB - Abs using the kappaII-A2 V gene segment predominate the human Ab repertoire to
the Haemophilus influenzae b (Hib) polysaccharide (PS). All A2 anti-Hib PS Abs
sequenced to date possess a 10-amino acid L chain complementarity-determining
region-3 (CDR-3) having an insertional arginine (Arg) at position 95a, the V-J
junction. These findings suggest an essential requirement for this conserved Arg
residue in determining Hib PS-binding affinity. We examined this requirement by
performing chain recombination experiments in which a series of A2 L chains,
differing at position 95a, were combined individually with an Fd region known to
generate a Hib PS-combining site when paired with an A2-Arg(95a)-Jkappa1 V
region. Hib PS binding of the recombinant Fabs was evaluated quantitatively using
a radioantigen-binding assay. Fabs having A2 L chains with either Arg or lysine
in position 95a in combination with Jkappa1 gave equivalent and strongest binding
to Hib PS. Fabs having A2-Jkappa1 L chains with either tyrosine, glycine,
alanine, leucine, serine, or threonine in position 95a, or having an A2-Arg(95a)
Jkappa3 L chain, gave intermediate binding. Fabs having A2-Jkappa1 L chains with
glutamate or aspartate at 95a or with no junctional residue showed little or no
Hib PS binding. These results demonstrate the importance of L chain junctional
residue, as well as Jkappa usage and CDR-3 length, in determining Hib PS-binding
affinity. Contrary to expectation, an Arg junctional residue is not essential for
generating either high or intermediate affinity-binding sites.
PMID- 9759905
TI - Therapeutic preparations of normal polyspecific IgG (IVIg) induce apoptosis in
human lymphocytes and monocytes: a novel mechanism of action of IVIg involving
the Fas apoptotic pathway.
AB - Therapeutic preparations of normal human IgG for i.v. use (i.v.Ig) exhibit a
broad spectrum of immunoregulatory activities in vitro and in vivo. I.v.Ig has
been shown to inhibit the proliferation of activated B and T lymphocytes and of
several autonomously growing cell lines. In this study, we demonstrate that
i.v.Ig induces apoptosis in leukemic cells of lymphocyte and monocyte lineage and
in CD40-activated normal tonsillar B cells, involving, at least in part, Fas
(CD95/APO-1) and activation of caspases. I.v.Ig-induced apoptosis was higher in
Fas-sensitive HuT78 cells than in Fas-resistant HuT78.B1 mutant cells, and
soluble Fas inhibited IVIg-induced apoptosis. I.v.Ig immunoprecipitated Fas from
Fas-expressing transfectants and recognized purified Fas/glutathione-S
transferase fusion proteins upon immunoblotting. Affinity-purified anti-Fas Abs
from i.v.Ig induced apoptosis of CEM T cells at a 120-fold lower concentration
than unfractionated i.v.Ig. Inhibitors of cysteine proteases of the caspase
family, caspase 1 (IL-1beta-converting enzyme) and caspase 3 (Yama/CPP32b),
partially inhibited i.v.Ig-induced apoptosis of CEM cells. Furthermore, cleavage
of poly(A)DP-ribose polymerase into an 85-kDa signature death fragment was
observed in CEM cells following i.v.Ig treatment. Thus, normal IgG induces
apoptosis in lymphocytes and monocytes. Our results provide evidence for a role
of Fas, bring new insights into the mechanisms of action of i.v.Ig in autoimmune
diseases, and suggest a role of normal Ig in controlling cell death and
proliferation.
PMID- 9759907
TI - A case of congenital mumps infection complicated with persistent pulmonary
hypertension.
AB - A low-birth-weight female baby was admitted with respiratory distress after
birth. Her mother had been diagnosed with mumps 4 weeks and 5 days prior to
delivery. Mumps IgM antibody was elevated in the neonate and mumps virus
ribonucleic acid was detected in the umbilical cord blood by reverse
transcription-polymerase chain reaction. The perinatal virus infection was
complicated with persistent pulmonary hypertension of the newborn and pulmonary
hemorrhage. Successful treatment included the use of high frequency oscillation
ventilation together with the administration of artificial surfactant.
PMID- 9759906
TI - Prenatal ultrasonography: clinical and radiological findings in a boy with
fibrochondrogenesis.
AB - Fibrochondrogenesis, a rare lethal chondrodysplasia has been reported on nine
patients. We report on a boy with fibrochondrogenesis whose parents were second
cousins. Prenatal ultrasonography performed at 22 weeks of gestation revealed an
intrauterine growth retardation, an apparently large head, an hypoplasia of the
thorax, a prominent abdomen, rhizomelic limbs, and wide metaphysis. The latest
have never been reported in other lethal dysplasias.
PMID- 9759908
TI - Pregnancy performance and outcomes associated with diabetic nephropathy.
AB - The purpose of the current study is to report the effect of diabetic nephropathy
on pregnancy outcomes based on a review of the world's literature from 1981 to
1996. In addition, the effects of pregnancy on renal function in a select
subpopulation of patients is also presented. The Medline Computer System was used
to survey the English language literature on diabetic nephropathy complicating
pregnancy between 1981 and 1996, which yielded a total patient population of 315.
The database was analyzed according to patient population, clinical management,
maternal complications and outcomes, and fetal complications and outcomes. The
frequency of chronic hypertension was 42% with 60% of women manifesting
hypertension by the third trimester. Pre-eclampsia developed in 41% of patients;
proliferative retinopathy was observed in 63% of patients prior to pregnancy, and
cesarean section delivery was performed in 74% of the patients. Among the fetal
outcomes, intrauterine growth restriction (IUGR) was observed in 15%, preterm
delivery in 22%, and major congenital malformations in 8% of the patients
included in the database. The observed overall perinatal morality rate was 5%.
Gestational age at delivery was significantly correlated with first-trimester
Cr/Cl (p < 0.01), third-trimester Cr/Cl (p < 0.05), third trimester proteinuria
(p < 0.01), and third-trimester blood pressure (p < 0.001). Birth weight was
significantly correlated with first-trimester Cr/Cl (p < 0.01), third-trimester
Cr/Cl (p < 0.001), third-trimester proteinuria (p < 0.01), and third-trimester
blood pressure (p < 0.001). Of the 185 patients available for long-term follow-up
(mean 35 months), 17% developed end-stage renal disease, and 5% died as a result
of renal insufficiency. Among the renovascular parameters, proteinuria and mean
arterial pressure significantly increased from the first to the third trimester
(p < 0.05). When these parameters were evaluated at follow-up, blood pressure did
not show a significant increase from first trimester values, however, proteinuria
did show a weak, but significant, increase postpartum. These data suggest that
with contemporary methods of perinatal care, fetal survival rates of 95% are
achievable in diabetic women with nephropathy. Furthermore, although many women
experienced a temporary decline in renal function during gestation, pregnancy per
se, does not appear to worsen the natural progression to end-stage renal disease
for most women with renal insufficiency.
PMID- 9759909
TI - Successful abdominal delivery in a woman with sonographic diagnosis of diffuse
cavernous hemangioma of the uterus.
AB - Diffuse hemangioma of the pregnant uterus is a serious lesion. We report the
first case of a successful cesarean section at term following expectant
management of pregnancy in a patient with presumed isolated diffuse cavernous
hemangioma of the uterus and protein S deficiency. The sonographic diagnosis and
clinical management of this condition is described. The presented successful
pregnancy underlines that, under close surveillance, consideration should be
given to a conservative approach to this sonographic finding during pregnancy, as
even an abdominal delivery does not imply hysterectomy inevitably.
PMID- 9759910
TI - Stem cell factor (SCF) levels in newborns.
AB - We studied Stem cell factor (SCF) levels in 15 mother-newborn pairs, 15 healthy
adult controls, and 16 newborn with bacterial sepsis. SCF levels were also
determined in six newborns with sepsis before and after completion of treatment.
SCF levels (pg/mL) were found to be 2141 +/- 529 in cord blood, 1385 +/- 314 in
mothers, 1546 +/- 443 in healthy adult controls, and 1742 +/- 655 in septic
newborns. Cord blood SCF levels were significantly higher than their mothers' and
healthy controls (p < 0.05). There were no differences in SCF levels between
mothers and healthy adult controls. No correlation was found between the SCF
levels and absolute neutrophil counts. There were no differences in SCF levels
between the before and after treatment levels in six newborn with sepsis. In
conclusion, our study suggests that SCF levels were increased in cord blood, and
this increase is not a reflection of mothers' levels. SCF levels do not show
significant changes during sepsis in newborns.
PMID- 9759911
TI - Antepartum fetal intracranial hemorrhage, predisposing factors and prenatal
sonography: a review.
AB - Our objective was to review current literature pertaining to antepartum fetal
intracranial hemorrhage. To this goal we selected all manuscripts published in
the English language regarding this topic obtained from a MEDLINE search for 1966
through January 1998. Additional sources were identified through cross
referencing. Antenatal fetal intracranial hemorrhage may occur spontaneously, or
occur in association with various maternal or fetal conditions. Predisposing
maternal conditions at risk for this occurrence include alloimmune and idiopathic
thrombocytopenia, von Willebrand's disease, specific medications (warfarin) or
illicit drug (cocaine) abuse, seizures, severe abdominal trauma inflicting
subsequent fetal injury, amniocentesis, cholestasis of pregnancy and febrile
disease. Predisposing fetal conditions include congenital factor-X and factor-V
deficiencies, hemorrhage into various congenital tumors, twin-twin transfusion,
demise of a co-twin, or fetomaternal hemorrhage. Currently, antepartum fetal
intracranial hemorrhage may be diagnosed by imaging techniques including
ultrasonography and less frequently, magnetic resonance imaging. Early real-time
sonographic signs of intracranial hemorrhage consist of irregular echogenic
patterns representing the associated hematoma that may clearly distort normal
intracranial structures. Recent reports have suggested Doppler flow velocimetry
and color Doppler imaging as additional tools in detecting fetal intracranial
hemorrhage. Various types of antenatal fetal intracranial hemorrhages that have
been visualized sonographically include intraventricular, periventricular,
subependymal, parenchymal, subdural, and intracerebellar events. Active
hemorrhages may be associated with fetal distress manifested by fetal heart rate
changes. Infrequently, antenatal ultrasonographic depiction of intracranial
hemorrhage may precede devastating sequelae such as hydrocephalus,
hydranencephaly, porencephaly, or microcephaly. Due to the significant associated
neonatal neurological impairment and potential medicolegal implications of
antepartum fetal intracranial hemorrhage, it follows that obstetricians and
sonographers should be familiar with predisposing factors and typical diagnostic
imaging findings of these events.
PMID- 9759912
TI - Lower thoracic spinal cord injury--a severe complication of shoulder dystocia.
AB - Fundal pressure as a maneuver for the relief of shoulder dystocia is associated
with up to a 77% fetal injury rate. The usual injuries involve the brachial
plexus or orthopedic injuries. We now report a severe lower thoracic spinal cord
injury with permanent neurological injury when fundal pressure was applied in an
attempt to relieve shoulder dystocia. Shoulder dystocia occurred in a 28-year-old
nulliparous woman. A series of manual maneuvers to include episiotomy extension,
McRoberts, suprapubic pressure, Woods screw, and extraction of the posterior arm
all failed to achieve delivery. During these maneuvers, but not coordinated with
them, fundal pressure was applied by multiple individuals. The Zavanelli maneuver
and cesarean delivery ultimately allowed delivery. On Day 2 of life marked
decrease in lower extremity motor function, over-flow urinary incontinence, and
rectal incontinence led to imaging studies that revealed focal spinal cord injury
at T-9 through T-12. Compressive forces applied to the fetal spine during fundal
pressure is the likely cause of the lower thoracic spinal cord injury manifest by
this newborn.
PMID- 9759913
TI - Right ventricular size is acutely decreased by inhaled nitric oxide in newborns
with pulmonary hypertension.
AB - The pressure and volume demands of the right and left ventricles may dramatically
change following selective pulmonary vasodilation in newborns with pulmonary
hypertension. Thus, ventricular planimetry was performed by two-dimensional
echocardiography in 35 newborns with lung disease and increased pulmonary
vascular resistance who were treated with inhaled nitric oxide to determine the
influence of therapy on right and left ventricular size and function. The end
diastolic and end-systolic areas of each ventricle were measured from apical 4
chamber images before, and 30 to 60 minutes after, the onset of 20 parts per
million inhaled nitric oxide. Estimates of ventricular function were determined
by the systolic decrease in ventricular area, (diastolic area - systolic area) x
100/diastolic area. Heart rate, systemic blood pressure, and left ventricular
areas did not change. However, the oxygenation index, the proportion of right-to
left ductal shunt (nonrestrictive ductus arteriosus, n = 22), the systolic
pulmonary arterial pressure (closed or restrictive ductus arteriosus, n = 13),
and the right ventricular diastolic and systolic areas were decreased after
nitric oxide inhalation. The baseline systolic decrease in left ventricular area
was lower in a subgroup of patients who developed an increase in left ventricular
diastolic area following nitric oxide inhalation. Thus, nitric oxide improves
pulmonary hemodynamics and decreases right ventricular size in newborns with lung
disease and pulmonary hypertension. However, newborns may develop an increase in
left ventricular size if left ventricular function is decreased prior to therapy.
PMID- 9759914
TI - The computerized perinatal database: are the data reliable?
AB - The purpose of this study is to examine the correctness of the clinical data from
the computerized perinatal database (PC-Log) at a Mayo Health System hospital.
This computerized database is used for electronic transmission of birth
certificates in Wisconsin. The paper medical record is chosen for the comparison.
Random selection of 99 charts from a total of 893 births at a tertiary perinatal
center during 1995. Of 310 fields in the database, 32 variables were compared to
a hand abstraction of the paper medical record. PC-Log had 100% positive
predictive value (PPV) for eclampsia, prolonged rupture of membranes, pre
existing diabetes, cesarean section, and transports. The sensitivity,
specificity, and PPV for other variables (abortion, congenital anomalies,
gestational diabetes, maternal hypertension, and maternal employment) showed
moderate to high agreement, but was poor for maternal ethanol use during
pregnancy. Compared to hand abstraction, PC-Log had no recorded cases of
substance abuse, antenatal steroids, hyaline membrane disease, circumcision,
maternal and infant length of stay. Means for birth weight 5 minute Apgar scores
did not differ, and the correlations were r = 0.982 and r = 0.960. The PC-Log
showed good agreement for many but not all the variables of clinical interest.
PMID- 9759915
TI - ATP released by LPS increases nitric oxide production in raw 264.7 macrophage
cell line via P2Z/P2X7 receptors.
AB - P2Z/P2X7 receptor is a particular type of purinoceptor, which is selectively
expressed on the surface of immune cells in neuronal and non-neuronal tissues.
Despite intensive research on its involvement in the immune response, the exact
mechanism whereby it affects intercellular signaling is far from clear yet. In
this study, the effect of activation P2Z/P2X7 receptor was investigated on the
bacterial lipopolysaccharide induced nitric oxide production in RAW 264.7
macrophage call line using the nitrite/nitrate assay. The P2Z/P2X7 receptor
agonist 3'-O-(4-benzoylbenzoyl)-adenosine 5'triphosphate increased concentration
dependency the lipoplysaccharide (10 microg/ml) induced nitric oxide production
between 10 microM and 250 microM. ATP also increased nitric oxide production in
response to lipopolysaccharide, while ADP, 2-methylo-thio-adenosine 5'
triphosphate and adenosine 5'triphosphate-gamma-S was without effect.
Pretreatment with oxidized adenosine triphosphate, the selective P2Z/P2X7
receptor antagonise (300 microM-1 microM) strongly decreased lipopolysaccaride
induced nitric oxide production. Furthermore, on macrophages, pretreated with
oxidized adenosine 5'-triphosphate (300 microM-1 mM), 3'-O-(4-benzoylbenzoyl)
adenosine 5'-triphosphate and ATP did not affect lipopolysaccharide induced
nitric oxide production. 15 min lipopolysaccharide treatment induced a transient
and reversible release of endogenous ATP from RAW 264.7 cells, measured by the
luciferin-luciferase assay. The effect of lipopolysaccharide to promote ATP
release was concentration-dependent between 1-10 microg/ml. In summary, our
results show that P2Z/P2X7 receptor activation results in an increase in nitric
oxide production in response to lipopolysaccharide challenge. Since the P2Z/P2X7
receptor antagonist oxidized adenosine triphosphate decreased lipopolysaccharide
induced nitric oxide production, and lipopolysaccharide was able to promote ATP
release from macrophage cells, it seems likely that endogenous ATP is involved in
nitric oxide formation during endotoxin challenge.
PMID- 9759916
TI - Effect of neonatal exposure to monosodium L-glutamate on regional GABA release
during postnatal development.
AB - Monosodium L-glutamate (MSG) causes neuronal lesions in certain brain regions
when systemically given to young animals. Also, when glutamate (Glu) builds up in
the intersynaptic space, it induces neuroexcitatory and neurocytotoxic effects,
events mediated by several Glu receptors. Some of these receptors such as NMDA
and AMPA receptors are present in the very earliest developmental stages of the
central nervous system and play a major role in neuronal plasticity during
synaptogenesis. In this paper, the GABAergic system vulnerability was determined
in terms of [3H]-GABA release during postnatal development. [3H]-GABA release on
days 14, 21, 30, and 60 days after birth was assessed for the cerebral cortex
(CC), hippocampus (Hp) and striatum (S) in rats perinatally treated at days 1, 3,
5, and 7 after birth with MSG. The results show a major decrease in baseline [3H]
GABA release in the CC (30 and 60 days after birth) and the Hp (beginning day 21
after birth) vs the control groups [intact rats and rats given a NaCl solution
equimolar to that of MSG (eqNaCl)] while in the S baseline release remained
unchanged. Stimulated [3H]-GABA release was decreased in the CC on days 14 and 21
after birth and significantly increased on day 60 after birth vs the controls. In
the Hp, a decrease was seen on days 14, 21, and 60 after birth vs the controls
while stimulated [3H]-GABA release was decreased in the S vs the controls at all
ages studied. No significant differences in stimulated [3H]-GABA release were
found between the intact group and the group treated with eqNaCl on days 30 and
60 after birth. Results show that CC, Hp and S GABAergic neurones are a major
target for the effect of perinatally given MSG and suggest a possible decrease in
the number of Hp GABAergic neurones while these results in CC and S suggest a
modified neuronal plasticity. NMDA receptor and calcium involvement are discussed
as significant mediators of these events.
PMID- 9759917
TI - L-arginine uptake in rat cerebral mitochondria.
AB - The kinetics of L-[14C]arginine (L-[14C]Arg) uptake and the effects of potential
competitors on the uptake were analysed in nonsynaptic mitochondria isolated from
rat cerebral hemispheres. Analysis of uptake kinetics revealed a high affinity
component with a mean Km = 0.08 mM, and Vmax = 1.89 nmoles/min/mg, and a very low
affinity component probably manifesting diffusion. The uptake of 25 mM L-Arg was
strongly inhibited by a 20-fold excess of L-lysine (L-Lys) and L-ornithine (L
Orn), but not by D-Arg nor any neutral amino acid, which resembles the
characteristics of the gamma+ transport system operating in the nerve- and glia
cell-, and synaptic plasma membranes. Also in consistance with the other gamma+
systems, L-Arg uptake to mitochondria was inhibited by a nitric oxide synthase
(NOS) inhibitor L-N-monomethyl arginine (L-NMMA), but not by another NOS
inhibitor NG-nitro-L-arginine (L-NNA). However, the uptake was very little
affected by 20-fold excess of L-histidine (L-His), L-glutamate (L-Glu) or L
glutamine (L-Gln), which is in contrast to the nonmitochondrial systems. The
uptake was only marginally influenced by cytoplasmic L-Arg metabolites: ammonia,
creatine, putrescine, or the mitochondrial L-Arg decarboxylation product,
agmatine.
PMID- 9759918
TI - Metallothionein-I+II induction by zinc and copper in primary cultures of rat
microglia.
AB - Metallothioneins (MTs) are a family of low molecular weight proteins which in
rodents comprise four isoforms (MT-I to -IV). MT-I+II are widely expressed
isoforms which are highly inducible by factors such as heavy metals and a number
of hormones. The expression of these isoforms in the brain has been regarded as
basically astrocytic, and to a lower extent, neuronal. We, however, demonstrate
in this report, by radioimmunoassay and immunocytochemistry, that MT-I+II are
expressed in primary cultures of rat microglia and that, furthermore, they are
inducible by zinc and copper. Thus all major brain cell types may express the MT
I+II isoforms and respond with increased protein levels to physiological stimuli
such as increased extracellular zinc and copper content. In contrast, microglia
MT-I+II levels are not affected by either the glucocorticoid dexamethasone or the
cytokine IL-1 under the experimental conditions.
PMID- 9759919
TI - Heparin modulates adenine nucleotide hydrolysis by synaptosomes from cerebral
cortex.
AB - The modulatory effect of heparin and dextran sulfate 500,000 (sulfated
polysaccharides) was studied on ATPDase and 5'-nucleotidase activities. These
enzymes participate in the degradation of ATP and adenosine production at the
synaptic cleft level. Nucleotide hydrolysis was inhibited by heparin and dextran
sulfate 500,000. For ADP, the inhibition was more evident at low cation
concentrations (0.15 mM Ca2+ or Mg2+), reaching a maximum of 75%. For ATP, the
inhibitory effect was less prominent and independent of divalent cation
concentration, reaching a maximum of 25%. For AMP, the inhibition observed was
similar with either relatively high (1 mM) or with low Mg2+ concentrations tested
(0.1 mM) and reached a maximum of 35%. K+ did not change the inhibitory potency
of sulfated polysaccharide suggesting that its effects were not exclusively
related to charge interaction. These results suggest that heparin and possibly
other naturally occurring sulfated polysaccharides may have a potential role as
modulator of extracellular nucleotide hydrolysis in the synaptic cleft region.
PMID- 9759920
TI - Enhancement of serotonin transporter function by tumor necrosis factor alpha but
not by interleukin-6.
AB - Serotonin (5-HT) is a prime candidate for studies of the interaction between the
nervous and immune systems, since it is both an important neurotransmitter and
released at high concentrations at sites of inflammation. Serotonergic
neurotransmission is regulated by the 5-HT transporter (5-HTT), which determines
the magnitude and duration of serotonergic responses. Since tumor necrosis factor
alpha (TNF-alpha) and interleukin-6 are two inflammatory mediators that are
central to the initiation of inflammation, we studied the impact of these
cytokines on the 5-HTT. As model system we used a cell line which constitutively
expresses the 5-HTT, namely the choriocarcinoma cell line JAR. We found that TNF
alpha enhances 5-HT uptake, with a doubling of the maximal velocity of uptake.
Interleukin-6, on the other hand, had no effect. We thus show for the first time
that the cytokine TNF-alpha modulates 5-HTT function. Furthermore, we propose a
molecular mechanism for this effect. Since both 5-HT and TNF-alpha are elevated
at sites of inflammation, TNF-alpha may act to renormalize 5-HT levels by way of
its effect on the 5-HTT. This is especially important for the central nervous
system, where the TNF-alpha effect shown here can aid in preventing disturbances
of serotonergic neurotransmission.
PMID- 9759921
TI - The role of nitric oxide in striatal acetylcholine release induced by N-methyl-D
aspartate.
AB - Effect of nitric oxide (NO) on striatal acetylcholine (ACh) release induced by N
methyl-D-aspartate (NMDA) was investigated in freely moving rats by means of
microdialysis. NMDA caused a significant increase in ACh release in the striatum,
which was blocked by the specific NMDA receptor antagonists, (+/-)-3-(2
carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) and (+)-5-methyl-10,11
dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801),
indicating that agonist-evoked increase in ACh release in the striatum was
through an NMDA receptor-mediated mechanism. NG-monomethyl-L-arginine acetate
salt (L-NMMA; a NO synthase inhibitor) facilitated NMDA-evoked increase in ACh
release, while L-arginine (the precursor of NO) inhibited the ACh release. The
increase by L-NMMA of ACh release induced by the NMDA was also blocked by L
arginine. These results suggest that NO induced by NMDA receptor-mediated
mechanism in cholinergic neurons may mediate an inhibitory regulation of ACh
release.
PMID- 9759922
TI - Calcium influx via ionotropic glutamate receptors causes long lasting inhibition
of metabotropic glutamate receptor-coupled phosphoinositide hydrolysis.
AB - Functional interaction between ionotropic and metabotropic glutamate receptors
(iGluR and mGluR respectively) was studied in cerebellar granule cell cultures
using quisqualate (QA), the most potent agonist of phosphoinositide hydrolysis
coupled mGluR, and N-methyl-D-aspartate (NMDA) or kainate (KA) that activate
different classes of iGluR. Two h exposure to NMDA or KA resulted in a marked
reduction (about 75%) of QA-evoked PI hydrolysis. The efficacy of the two
agonists was about the same, but the potencies were different (IC50 for NMDA
about 35 microM and for KA about 70 microM). NMDA-induced depression of QA
stimulated PI hydrolysis was relatively long lasting but reversible. Recovery
required protein synthesis. In nominally Ca2+-free medium both NMDA and KA failed
to attenuate QA-stimulated PI hydrolysis. The effect of NMDA was prevented by the
NMDA receptor antagonist MK801, but not by the wide spectrum protein kinase
inhibitor staurosporin nor by the nitric oxide synthase inhibitor N omega-nitro-L
arginine. Cycloheximide and concanavalin A were also ineffective. The effect of
KA was prevented by the selective non-NMDA receptor antagonist 2,3-dihydroxy-6
nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX). Voltage sensitive Ca2+ channel
antagonists together with MK801 did not counteract the inhibition by KA of the QA
response. Both NMDA and KA attenuated PI hydrolysis evoked by the muscarinic
receptor agonist carbachol (about 30%), indicating that the activation of iGluRs
exerts a relatively general inhibitory effect on the function of different PLC
coupled metabotropic receptors. Consistent with this observation is that
treatments either with KA and NMDA induced an inhibition (about 30%) of NaF
stimulated PI hydrolysis which occurs through the direct activation of G
proteins. Our observations show that ionotropic glutamate receptor stimulation
induces a long lasting suppression of QA-evoked PI breakdown through a Ca2+
dependent mechanism which seems to involve receptor coupled transduction systems
downstream from mGluR. Such a Ca2+-dependent cross-talk involving ionotropic and
metabotropic receptors may play a role in certain events of synaptic plasticity.
PMID- 9759923
TI - Quantification of human dopamine D2s receptor interactions with G alpha(i,1,2)-
and G alpha(o)-proteins.
AB - A simple and rapid in vitro method for qualitative and quantitative estimation of
the G alpha-subunits interaction with the third intracellular loop of human D2s
dopamine receptor has been developed. For this purpose, D2s-CL3 was cloned in
pGEX-2T vector and expressed in E. coli BL21 DE3 as a fusion protein with
glutathione-S-transferase (D2s-CL3-GST). The resulting soluble construct was
purified by affinity chromatography on glutathione-Sepharose. G alpha-subunits
were expressed and purified as His-tagged proteins. For the assay of G alpha/D2s
CL3-GST interactions, varying concentrations of pure His-tagged G alpha-proteins
were immobilized on His-Bind Resin and titrated with D2s-CL3-GST fusion protein.
G alpha/D2s-CL3-GST interactions were quantified by GST activity determination
assay. It was shown that the fusion protein interacts specifically with different
G alpha proteins, especially with G alpha(i) proteins. Based on saturation
binding analyses, Kd values were determined revealing the highest affinity of His
G alpha(i,2) binding to the fusion protein. The affinities for G alpha(i)/D2s-CL3
GST protein interactions estimated in this way were in nanomolar range of
concentrations.
PMID- 9759924
TI - Elevation of cerebral proteases after systemic administration of aluminum.
AB - The levels of three proteases in the cerebral cortex of rats following a three
week exposure to aluminum, were measured. The activity of apopain (CPP32), an
interleukin 1beta converting enzyme (ICE)-like cysteine protease specifically
associated with apoptosis, was increased following dosing with aluminum. The
activity of calcium-activated neutral protease, calpain, was also increased.
However, the enzyme activity of trypsin-like serine protease, known to be
elevated by oxidative events, was unchanged. Since aluminum is suspected as a
possible factor in the pathogenesis of Alzheimer's disease and other neurological
diseases, it is speculated that changed levels in proteolytic enzymes may relate
to the neurotoxicity of aluminum.
PMID- 9759925
TI - Liver-directed gene transfer vectors.
AB - The ultimate goal of liver-directed gene therapy for genetic diseases is the
stable expression of a therapeutic transgene in a significant proportion of
hepatocytes. This article considers the various liver-directed gene transfer
procedures studied so far. Performances and limitations of currently available
vector systems are discussed with respect to their clinical relevance. Although
some improvements have been reported, naked DNA and nonviral gene transfer
vectors induce transient expression in only a limited number of cells. Clinical
applications of retrovirus-mediated gene transfer are hampered by the need to
induce hepatocyte division. First-generation adenovirus vectors are highly
efficient; however, they induce an immune response leading to the rapid rejection
of transduced cells. Promising new vector systems have emerged, including gutless
adenovirus vectors, adeno-associated vectors, and lentivirus vectors. However,
these systems are still poorly documented and their relevance to liver-directed
gene therapy must be confirmed.
PMID- 9759926
TI - Apoptosis by retrovirus- and adenovirus-mediated gene transfer of Fas ligand to
glioma cells: implications for gene therapy.
AB - Astrocytic tumors frequently express Fas/APO-1 (Fas), in sharp contrast to
surrounding normal brain cells, providing a potential window through which
selective killing of tumor cells could be pursued. To assess this possibility, we
transduced Fas into U251, a glioma cell line resistant to anti-Fas antibody
mediated apoptosis, and obtained transfectants with high levels of Fas
expression. Anti-Fas antibody showed significantly enhanced cytotoxicity for the
transfectants, suggesting that U251 cells maintained an intercellular cascade of
Fas-mediated apoptosis. When U251 transfectants with high-level Fas expression
were transduced with Fas ligand-encoding gene via retrovirus, they were
unaffected by exposure to anti-Fas antibody or Fas ligand adenovirus (Adeno-FL).
Thus, retroviral induction of Fas ligand into the glioma cells with high levels
of Fas led to the selection of cells that were resistant to Fas-dependent
apoptosis. These resistant U251 transfectants were susceptible to FADD adenovirus
(Adeno-FADD)-induced apoptosis, indicating that a cascade of death signals was
blocked at the steps between Fas ligand and FADD. As for adenoviral transduction
of Fas ligand into gliomas, gliomas with a relatively high level of expression of
Fas were remarkably sensitive to Adeno-FL-induced apoptosis. Besides, Adeno-FADD
induced pronounced apoptosis in all glioma cells. Our data suggest the
possibility of using adenovirus-mediated transduction of Fas ligand and FADD
genes as a therapeutic approach to target gliomas.
PMID- 9759927
TI - Use of nonautologous microencapsulated fibroblasts in growth hormone gene therapy
to improve growth of midget swine.
AB - The aim of the present study was to investigate the expression activity, both in
vitro and in vivo, of the porcine growth hormone complementary DNA (pGH cDNA) in
porcine fetal fibroblast (PFF) cells. The pGH gene had been constructed inside
the bicistronic retroviral vector PSN and subsequently transfected into PFF cells
further encapsulated with immunoprotective microcapsules. This would provide a
way to evaluate the improvement in growth performance of Tao-Yuan swine by the
use of nonautologous microencapsulated fibroblasts carrying the pGH cDNA via the
technique of somatic gene therapy. Results from Southern blot analysis confirmed
that the full length of the pGH cDNA was completely integrated into the genome of
the PFF cells after they had been infected one to four times using a PSN
retroviral vector. Moreover, Northern blot analysis showed that high
transcription activity was present in clones infected twice, and exogenous pGH
secretion was found when the pGH-infected PFF had been further cultured for 48 hr
in vitro and subjected to immunoblot assay. Encapsulation of the pGH-PFF with an
alginate-poly-L-lysine-alginate membrane did not show any deterioration in their
proliferation and survival both in vitro and in vivo. The pGH gene in
encapsulated recombinant fibroblasts was fully expressed after it had been
transplanted into the peritoneal cavity of the Tao-Yuan swine, and reverse
transcription-polymerase chain reaction (RT-PCR) analysis was performed on the
microcapsules retrieved 1 month later. The feasibility of pGH gene therapy to
improve midget Tao-Yuan swine growth enhancement is further supported by the fact
that transplantation of the encapsulated recombinant fibroblast cells resulted in
a much more significant increase in weight gain than in those swine in either the
age-matched untreated control group or in those that had been transplanted with
uncapsulated recombinant PFF cells (10.56 +/- 1.01 kg versus 6.95 +/- 0.94 and
5.27 +/- 1.30 kg; p < 0.05). These experimental data suggest that growth hormone
gene therapy did provide an alternative approach for growth improvement in midget
Tao-Yuan swine.
PMID- 9759928
TI - Anti-HIV type 1 activity of wild-type and functional defective RANTES intrakine
in primary human lymphocytes.
AB - We have developed a genetic "intrakine" strategy to inactivate the CC-chemokine
receptor 5 (CCR-5), the principal coreceptor for macrophage (M)-tropic HIV-1
viruses (Yang et al, 1997). The inactivation of CCR5 was achieved by targeting a
modified CC-chemokine (RANTES) to the lumen of the endoplasmic reticulum (ER) to
block the transport of the newly synthesized CCR-5. The transduced lymphocytes
with the phenotypic CCR5 knockout were shown to be resistant to M-tropic HIV-1
infection. This study illustrated the feasibility of the intrakine strategy to
block HIV-1 infection. In our current study, the potential clinical application
of the intrakine approach was further evaluated in human peripheral blood
lymphocytes (PBLs). PBLs were transduced with the RANTES intrakine gene by using
retroviral vectors with the truncated low-affinity human nerve growth factor
receptor (deltaNGFR) marker, and then isolated by an anti-NGFR antibody/magnetic
bead method. The surface expression of CCR-5 in the transduced lymphocytes was
dramatically inhibited, as demonstrated by flow cytometric assays. The transduced
PBLs were shown to resist various types of M-tropic HIV-1 virus infection. The
cell viability, cell proliferation rates, and cell surface markers of the
intrakine-transduced PBLs were shown to be comparable to those of control PBLs.
The transduced PBLs were also found to respond to the stimulation of various CXC-
and CC-chemokines, other than RANTES. The transduced PBLs responded to tetanus
antigen stimulation by increasing IL-2 production and cell proliferation. In
addition, a functionally defective mutant of RANTES that retains its binding
activity to CCR-5, but loses its signaling ability, was used to generate a mutant
RANTES intrakine. The primary lymphocytes transduced with the mutant RANTES
intrakine were found to be resistant to M-tropic HIV-1 infection. From these
results, we conclude that the primary human lymphocytes transduced with either
the wild-type or functionally defective RANTES intrakine are resistant to M
tropic HIV-1 infection, and maintain their basic biological functions. This
study, therefore, indicates the potential clinical application of the intrakine
approach for HIV-1 gene therapy.
PMID- 9759929
TI - Ganciclovir chemoablation of herpes thymidine kinase suicide gene-modified tumors
produces tumor necrosis and induces systemic immune responses.
AB - The goal of this work was to identify potential host immune responses to
thymidine kinase (TK) suicide gene-modified tumors undergoing chemoablation
induced by the prodrug ganciclovir (GCV). The aims were to measure the efficacy
and specificity of immunity induced against unmodified tumor, to identify
qualitative or quantitative changes in the host response to TK+ tumors undergoing
chemoablation that may contribute to the induction of antitumor immunity, and to
compare critically the induction of immunity by chemoablation of TK-modified
tumors with that of other methods of immunization in this tumor model and in
response to other well-defined model antigens. Animals treated with TK+ tumors
and GCV developed specific resistance to rechallenge with unmodified tumor. GCV
induced significant tumor necrosis, which was associated with a pronounced host
cell infiltrate composed of polymorphonuclear cells, both CD4+ and CD8+ T
lymphocytes, and increased intratumoral IL-12. Cyclophosphamide-treated mice
exhibited no such host response despite the induction of tumor necrosis. CTL
responses to defined antigens in TK+ cells were greater in animals treated with
prodrug than were those in animals not treated with prodrug but harboring live
TK+ cells. Similar degrees of immunity were produced by immunization with
irradiated cells.
PMID- 9759930
TI - Locoregional response and increased natural killer activity after intratumoral
injection of HLA-B7/beta2-microglobulin gene in patients with cancer.
AB - The purpose of this study was to assess the therapeutic potential of injecting
the gene for HLA-B7/beta2-microglobulin into the subcutaneous metastatic nodules
of patients who are refractory to conventional treatments. The nine patients
evaluated were divided into three groups and given escalating doses of DNA (20,
40, and 100 microg of the HLA-B7 plasmid DNA/lipid complex for each group) every
2 weeks. Biopsy specimens from the treated tumor nodules of all nine patients
were positive for the presence of DNA and for HLA-B7 mRNA expression. Moreover,
in six of the nine patients, immunohistology of tumor biopsy samples revealed the
expression of recombinant HLA-B7 protein. Also, all nine patients showed an
increase in NK activity in their circulating peripheral blood lymphocytes. In two
lung cancer patients, one partial and one mixed response was observed after gene
transfer. These responses were confined to the treated nodules and the untreated
locoregional lymph nodes; the lung masses showed no regression. Remission
durations were 14 and 6 weeks, respectively, and in a total of 35 cycles no
significant toxicities were observed. Immunohistologic analysis revealed an
increased infiltration of CD4+ T cells, macrophages, and NK cells after therapy.
In two responding cases, direct intratumoral injection of an allogeneic class I
gene could elicit an antitumor response in locoregional areas, possibly through
the activation of NK cells.
PMID- 9759931
TI - Reinnervation of motor endplates and increased muscle fiber size after human
insulin-like growth factor I gene transfer into the paralyzed larynx.
AB - Current surgical strategies for the treatment of laryngeal paralysis are limited
by the muscle atrophy associated with denervation. Moreover, attempts at
reinnervation have not effected significant change in surgical outcome. To
address this clinical problem, we have developed a rat laryngeal paralysis model
to study novel gene transfer strategies. Using this model, the human insulin-like
growth factor I (hIGF-I) gene was introduced into paralyzed rat laryngeal muscle
to assess the benefit of sustained local hIGF-I production. A muscle-specific
nonviral vector containing the alpha-actin promoter and hIGF-I gene was used in
formulation with a polyvinyl-based delivery system and injected into paralyzed
adult rat laryngeal muscle. Twenty-eight days after a single injection, gene
transfer efficiency, muscle fiber size, motor endplate length, and nerve-to-motor
endplate contact were evaluated. Gene transfer was detected in 100% of injected
animals by PCR. Gene transfer with expression, as measured by RT-PCR for hIGF-I
mRNA, occurred in 81.3 % of injected animals. When compared with controls, hIGF-I
transfected animals presented a significant increase in muscle fiber diameter
[17.56 (+/-0.97 SD) microm versus 14.70 (+/-1.43 SD) microm; p = 0.0002], a
significant decrease in motor endplate length [20.88 (+/-1.42 SD) microm versus
25.41 (+/-3.19 SD) microm; p = 0.0025], and a significant increase in percentage
of endplates with nerve contact (20.3% (+/-13.9 SD) versus 4.4% (+/-4.2 SD); p =
0.0079). In the context of laryngeal paralysis, gene therapy represents a
tremendous opportunity to augment current surgical treatment modalities by
preventing or reversing muscle atrophy, and by enhancing nerve sprouting and
reinnervation.
PMID- 9759932
TI - Immune response to Philadelphia chromosome-positive acute lymphoblastic leukemia
induced by expression of CD80, interleukin 2, and granulocyte-macrophage colony
stimulating factor.
AB - We examined the potential of generating an immune response against Philadelphia
chromosome-positive acute lymphoblastic leukemia. The immunostimulatory molecules
chosen for this study were the cytokines IL-2 and GM-CSF and the costimulatory
ligand CD80 (B7.1). We used a murine model based on a BALB/c pre-B cell line,
BM185wt, in which leukemia is induced by the p185 BCR-ABL oncogenic product,
which reproduces Philadelphia chromosome-positive ALL. BM185wt cells were
transduced with retroviral vectors and the transduced clones expressing mIL-2,
mGM-CSF, or mCD80 were used for challenge. Expression of the immunomodulators by
BM185 cells was correlated with delay in leukemia development in immunocompetent
mice, but not in immunodeficient mice, indicating an immune response against the
modified leukemia cells. Expression of CD80 caused leukemia rejection in 50% of
the cohort, which was associated with the CD4+ and CD8+ T cell-dependent
development of anti-leukemia cytotoxic T lymphocytes. Furthermore, mice surviving
the BM185/CD80 challenge or preimmunized with irradiated BM185/CD80 cells
developed an immune response against subsequent challenge with the parental
leukemia. These studies provide evidence that immunotherapeutic approaches can be
developed for the treatment of ALL.
PMID- 9759933
TI - Antitumor activity of bax and p53 naked gene transfer in lung cancer: in vitro
and in vivo analysis.
AB - In vitro and in vivo data have demonstrated that virus-mediated p53 gene transfer
can induce active cell death and lung tumor regression. In contrast, the
therapeutic potential of bax, another apoptosis-inducing gene, has not been
described. We compared p53 and bax cytotoxic effects by transient transfection of
an average of 25 +/- 5% of the H-322 and H-358 bronchioloalveolar carcinoma cell
lines in vitro. Under these conditions, bax expression killed 70 to 90% of the
transfected cells whereas p53 killed only 40% of them. The killing activity of
both genes involved apoptosis, as shown by TUNEL staining. Surprisingly, BrdU
incorporation indicated that the cells that did resist Bax toxicity were blocked
in the pre-S phase of the cell cycle, a result expected for p53 only. In vivo,
repeated injections of naked DNA encoding Bax or p53 inhibited the growth of 4-mm
preestablished H-322 tumors in nude mice. Growth retardation only, and not
inhibition, was observed in H-358, a poorly transfectable and rapidly growing
tumor. These results indicate that Bax and p53 share a similar, strong antitumor
activity in vivo, even if the former is a more potent inducer of apoptosis in
vitro.
PMID- 9759935
TI - Biodistribution and gene expression of lipid/plasmid complexes after systemic
administration.
AB - The objectives of this study were to investigate the influence of physicochemical
properties of lipid/plasmid complexes on in vivo gene transfer and
biodistribution characteristics. Formulations based on 1,2-di-O-octadecenyl-3
trimethylammonium propane (DOTMA) and novel biodegradable cationic lipids, such
as ethyl dioleoyl phosphatidylcholine (EDOPC), ethyl palmitoyl myristyl
phosphatidylcholine (EPMPC), myristyl myristoyl carnitine ester (MMCE), and oleyl
oleoyl L-carnitine ester (DOLCE), were assessed for gene expression after tail
vein injection of lipid/plasmid complexes in mice. Gene expression was influenced
by cationic lipid structure, cationic lipid-to-colipid molar ratios, plasmid-to
lipid charge ratios, and precondensation liposome size. Detectable levels of
human growth hormone (hGH) in serum, human factor IX (hFIX) in plasma, and
chloramphenicol acetyltransferase (CAT) in the lung and liver were observed with
positively charged lipid/plasmid complexes prepared from 400-nm extruded
liposomes with a cationic lipid-to-colipid ratio of 4:1 (mol/mol). Intravenous
administration of lipid/CAT plasmid complexes resulted in distribution of plasmid
DNA mainly to the lung at 15 min after injection. Plasmid DNA accumulation in the
liver increased with time up to 24 hr postinjection. There was a 10-fold decrease
in the amount of plasmid DNA in the lung at 15 min after injection, when the
lipid/plasmid complex charge ratio was decreased from 3:1 to 0.5:1 (+/-). Bright
fluorescent aggregates were evident in in vivo-transfected lung with the
positively charged pCMV-CAT/DOLCE:dioleyl phosphatidylethanolamine (DOPE) (1:1,
mol/mol) complexes, while more discrete punctate fluorescence was observed with a
4:1 molar ratio of cationic lipid:colipid formulations. Preinjection of
polyanions such as plasmid, dextran sulfate, polycytidic acid, and polyinosinic
acid decreased hGH expression, whereas the preinjection of both positively
charged and neutral liposomes had no effect on hGH serum levels. Of the cationic
lipids tested, DOLCE was found to be the most effective potentially biodegradable
cationic lipid. A correlation between gene expression and cationic lipid:colipid
ratios and lipid-to-plasmid charge ratio was also observed for DOTMA- and DOLCE
based formulations.
PMID- 9759934
TI - A phase I study of adenovirus-mediated wild-type p53 gene transfer in patients
with advanced non-small cell lung cancer.
AB - Mutations of the tumor suppressor gene p53 are the most common genetic
alterations observed in human cancer. Loss of wild-type p53 function impairs cell
cycle arrest as well as repair mechanisms involved in response to DNA damage.
Further, apoptotic pathways as induced by radio- or chemotherapy are also
abrogated. Gene transfer of wild-type p53 was shown to reverse these deficiencies
and to induce apoptosis in vitro and in preclinical in vivo tumor models. A phase
I dose escalation study of a single intratumoral injection of a replication
defective adenoviral expression vector encoding wild-type p53 was carried out in
patients with incurable non-small cell lung cancer. All patients enrolled had p53
protein overexpression as a marker of mutant p53 status in pretreatment tumor
biopsies. Treatment was performed either by bronchoscopic intratumoral injection
or by CT-guided percutaneous intratumoral injection of the vector solution.
Fifteen patients were enrolled in two centers, and were treated at four different
dose levels ranging from 10(7) to 10(10) PFU (7.5 x 10(9) to 7.5 x 10(12)
particles). No clinically significant toxicity was observed. Successful transfer
of wild-type p53 was achieved only with higher vector doses. Vector-specific wild
type p53 RNA sequences could be demonstrated in posttreatment biopsies of six
patients. Transient local disease control by a single intratumoral injection of
the vector solution was observed in four of those six successfully transduced
patients. There was no evidence of clinical responses at untreated tumor sites.
Wild-type p53 gene therapy by intratumoral injection of a replication-defective
adenoviral expression vector is safe, feasible, and biologically effective in
patients with advanced non-small cell lung cancer.
PMID- 9759937
TI - Transduced fibroblasts and metachromatic leukodystrophy lymphocytes transfer
arylsulfatase A to myelinating glia and deficient cells in vitro.
AB - Metachromatic leukodystrophy (MLD) is a lysosomal storage disease, caused by
deficiency of arylsulfatase A (ASA), that manifests primarily in the white matter
of the nervous system. Currently, no specific treatment exists that will reverse
its fatal outcome. Replacement therapy has been hampered by the blood-brain
barrier (BBB). To circumvent this problem we designed an ex vivo gene therapy
strategy that includes the retrovirus-mediated ASA transduction of cells, such as
activated lymphocytes, that are able to traverse the BBB or other membranes of
the CNS. For this purpose, two recombinant retroviruses based on the pLXSN vector
were produced, containing the wild-type ASA cDNA or a pseudodeficiency ASA cDNA,
which encodes a smaller enzyme with normal activity. After transduction, ASA
activity increased more than 100-fold in fibroblasts from an MLD patient.
Furthermore, ASA-transduced MLD PBLs expressed 30 times higher ASA activity when
compared with control PBLs. Moreover, cell culture experiments demonstrated that
transduced fibroblasts could efficiently transfer ASA to deficient cells across a
transwell barrier, whereas transduced MLD lymphocytes could transfer ASA to
deficient fibroblasts only by direct cell-to-cell contact. Finally, ASA was taken
up by normal oligodendrocytes and Schwann cells, the target myelinating glial
cells for therapy in MLD. These data suggest possible short-term strategies for
transfer of ASA into the CNS via transduced autologous cells while long-term
strategies, related to autologous transduced bone marrow transplant, take effect
in patients.
PMID- 9759936
TI - Adenovirus-mediated granulocyte-macrophage colony-stimulating factor improves
lung pathology of pulmonary alveolar proteinosis in granulocyte-macrophage colony
stimulating factor-deficient mice.
AB - Mutation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene by
homologous recombination causes progressive pulmonary alveolar proteinosis (PAP)
in GM-CSF-deficient mice (GM-/-). The present study tested whether adenovirus
mediated expression of GM-CSF alters the progression of PAP in GM-/- mice. Adult
mice were pretreated with an anti-T cell receptor (TCR) antibody to block T cell
mediated immune response, followed by intratracheal instillation of deltaE1-E3
replication-deficient adenovirus expressing mouse GM-CSF (Av1mGM). Mice were
killed 1, 3, and 5 weeks after treatment to assess lungs for GM-CSF, surfactant
protein B (SP-B), alveolar macrophage maturation, and type II cell proliferation.
GM-CSF was detected in BAL fluid from GM-/- mice 1 week after Av1mGM treatment,
and GM-CSF mRNA was detected by RT-PCR through 5 weeks. Five weeks after Av1mGM
treatment, PAP was improved and SP-B decreased as assessed by ELISA and
immunostaining. Increased numbers of alveolar macrophages stained with alpha
naphthyl acetate esterase (alpha-NAE) following treatment with Av1mGM. Local
expression of GM-CSF with a recombinant adenovirus ameliorated PAP in the GM-/-
mice in association with enhanced maturation of alveolar macrophages.
PMID- 9759940
TI - NIH Recombinant DNA Advisory Committee data management report. June 18-19, 1998.
PMID- 9759938
TI - Impact of preexisting and induced humoral and cellular immune responses in an
adenovirus-based gene therapy phase I clinical trial for localized mesothelioma.
AB - Little is known about the immune responses induced by recombinant adenoviral (Ad)
vectors in humans. The humoral and cellular immune responses were therefore
analyzed in 21 patients with localized malignancy (mesothelioma), who received
intrapleurally high doses of a replication-defective Ad5 vector carrying a
suicide gene. Eight of 21 patients had pretreatment titers of neutralizing
antibodies (NAb) to Ad at > or =1:100. Peripheral blood mononuclear cells (PBMCs)
proliferated in response to adenoviral 5 structural proteins before treatment in
17 of 21 patients. Preexisting humoral and cellular immunity did not preclude
gene transfer. Vector instillation induced high titers of nonneutralizing and
neutralizing anti-Ad antibody (4- to 341-fold increase in 18 of 20 patients) in a
dose-dependent manner. Three patients generated antibodies to the transgene,
herpes simplex virus thymidine kinase. Ad5-specific proliferation of PBMCs
increased significantly (>3-fold) after vector administration in 12 of 21
patients in a dose-dependent manner. Thus, replication-defective Ad5 administered
intrapleurally induced significant humoral and cellular immune responses that
induced no obvious adverse clinical sequelae.
PMID- 9759939
TI - Evaluating the potential of germ line transmission after intravenous
administration of recombinant adenovirus in the C3H mouse.
AB - The goal of this study is to assess the likelihood that an adenoviral vector
disseminated to gonads will be transmitted to offspring. This study is based on
the observation that systemically administered vector can be detected in both
ovaries and testes, using sensitive nested PCR techniques. Although the extent of
vector dissemination to gonads is extremely small, as it is detectable only by
nested PCR, it is unclear where it is located within these tissues and whether
the DNA is capable of integration and transmission to offspring. A protocol was
developed in C3H mice to address this question. Both male and female C3H mice
were injected with a high dose of H5.001CBhOTC, an E1- and E4-deleted vector
expressing human ornithine transcarbamylase. This dose of vector was sufficient
to target 80% of hepatocytes (Gao et al., J. Virol. 1996; 70:8934-8943) and
disseminate, at low levels, to both ovaries and testes in 94% of animals as
determined by PCR. Vector-administered animals and controls were mated and 814
offspring were evaluated for germ line transmission of the adenoviral vector by
DNA hybridization of total cellular DNA extracted from the fetus. Southern blot
analysis showed no evidence of germ line transmission in 578 offspring of crosses
in which either one or both parents received recombinant adenovirus.
PMID- 9759941
TI - Is the strategy of universal hepatitis B vaccination necessary in low-endemic
countries?
PMID- 9759942
TI - Time to relief of episodic symptoms of gastro-oesophageal reflux disease. A
crossover comparison of single doses of the effervescent and standard
formulations of ranitidine.
AB - BACKGROUND: The length of time until symptom relief and the consistency of
response are important aspects of the management of episodes of gastro
oesophageal reflux disease (GORD). METHODS: In an open, randomized, crossover
study 98 patients treated 3 episodes of GORD with ranitidine effervescent
formulation and 3 with ranitidine standard formulation. The patients filled in a
diary card during the 1st h after each study medication. Satisfaction with the
formulations and the formulation of choice were determined at the end of the
study. RESULTS: A higher percentage of episodes with acceptable symptom relief
(82.4% versus 73.1% P=0.024) and a shorter time to acceptable symptom relief (27
min versus 36 min; P < 0.001) were achieved with the effervescent formulation.
Sixty-five per cent preferred the effervescent formulation (P < 0.01).
CONCLUSIONS: An increased consistency of response and a more rapid symptom relief
were achieved with treatment with the ranitidine effervescent formulation,
indicating it may be more appropriate for on-demand treatment in patients with
episodes of GORD.
PMID- 9759943
TI - Prospective study of the effect of the Belsey Mark-IV fundoplication on reflux
mechanisms.
AB - BACKGROUND: Transient lower esophageal sphincter relaxations (TLESRs) are the
major mechanism permitting gastroesophageal reflux (GER). Little information is
available on how anti-reflux surgery affects reflux mechanisms, especially
TLESRs. We evaluated the effects of partial fundoplication (Belsey Mark IV) on
reflux mechanisms. METHODS: Sixteen patients were prospectively studied before
and after Belsey Mark-IV operation by endoscopy, 24-h esophageal pH-metry, and
simultaneous recording of pH and lower esophageal sphincter (LES) characteristics
by sleeve manometry. RESULTS: The operation was successful in 14 of 16 patients
(87%). Fasting and postprandial reflux decreased significantly (P < 0.01) after
the operation. Partial fundoplication significantly (P < 0.05) decreased the
number of TLESRs per hour in the fasting and postprandial period from 3.2+/-0.4
and 5.6+/-0.5 to 1.7+/-0.3 and 2.8+/-0.4, respectively. The percentage of TLESRs
associated with reflux also decreased significantly (P < 0.05). Basal LES
pressure increased from 14.7+/-2.1 mmHg to 17.9+/-2.6 mmHg (not significant).
CONCLUSIONS: Partial fundoplication controls GER through a reduction in the
number of TLESRs and by decreasing the number of relaxations associated with
reflux.
PMID- 9759944
TI - Hyperplasia of gastric antral beta-microseminoprotein endocrine-like cells and
increased serum levels of beta-microseminoprotein in atrophic corpus gastritis.
AB - BACKGROUND: Beta-microseminoprotein is a 94-kDa protein present on most mucosal
surfaces in the body. It is produced in mucin cells but is also found in a
particular type of cells (E-cells) in the gastric antral mucosa. Most of these
cells also contain gastrin. In atrophic corpus gastritis the gastrin-producing
cells become hyperplastic, and the patients have hypergastrinemia. We wanted to
ascertain whether there is a similar effect on the E-cells and on the
concentration of beta-microseminoprotein in serum. METHODS: Antral biopsy
specimens from 10 patients with atrophic corpus gastritis and 10 controls were
stained immunohistochemically for beta-microseminoprotein and gastrin. beta
Microseminoprotein and gastrin were measured by radioimmunoassay in serum from 15
women with atrophic corpus gastritis and 31 healthy female blood donors. RESULTS:
There was a 3.5-fold increase of the number of E-cells (which also were
hypertrophic) and a 2.1 times higher serum concentration of beta
microseminoprotein in the patients with atrophic corpus gastritis than in the
control subjects. Gastrin was seen in 28% of the E-cells in patients with
atrophic corpus gastritis, compared with 87% in normal antral mucosa. There was
no correlation between the serum concentrations of beta-microseminoprotein and
gastrin. CONCLUSIONS: In atrophic corpus gastritis antrum E-cells undergo
hyperplasia and hypertrophy, and the proportion of E-cells containing gastrin
decreases. Increased amounts of beta-microseminoprotein are secreted to the blood
but uncorrelated with gastrin.
PMID- 9759945
TI - Effect of sucralfate on gastric mucosal inflammatory responses induced by
Helicobacter pylori lipopolysaccharide.
AB - BACKGROUND: Helicobacter pylori lipopolysaccharide is emerging as a primary
factor in the bacterium virulence, and its involvement in causing gastric mucosal
responses typical of gastritis has recently been shown. In this study we
investigated the effect of the antiulcer agent sucralfate on the expression of
regulatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-4
(IL-4), and epithelial cell apoptosis during H. pylori lipopolysaccharide-induced
acute gastritis. METHODS: The experiments were conducted with rats pretreated
intragastrically twice daily for 3 days with sucralfate at 100 mg/kg or the
vehicle. The rats were then subjected to intragastric surface epithelial
application of H. pylori lipopolysaccharide at 50 microg per animal and
maintained on the sucralfate or vehicle regimen for an additional 4 days. The
animals were killed 16 h after the last dose, and their gastric mucosal tissue
used for histologic assessment, quantitation of TNF-alpha and IL-4 expression,
and the assay of epithelial cell apoptosis. RESULTS: In the absence of
sucralfate, H. pylori lipopolysaccharide induced acute mucosal responses
characterized by the inflammatory infiltration of the lamina propria, hyperemia,
and epithelial hemorrhage. This was accompanied by an 11-fold increase in gastric
epithelial cell apoptosis and a 9-fold enhancement of the mucosal expression of
TNF-alpha, but the level of IL-4 fell by 15%. Intragastric administration of
sucralfate produced a 62% reduction in the extent of mucosal damage caused by H.
pylori lipopolysaccharide, a 51% decrease in the mucosal expression of TNF-alpha,
and a 7-fold reduction in the extent of epithelial cell apoptosis, whereas the
expression of IL-4 increased by 52%. CONCLUSIONS: Gastric mucosal inflammatory
responses to H. pylori lipopolysaccharide are characterized by a massive
enhancement of the proinflammatory cytokine TNF-alpha and epithelial cell
apoptosis and repression of IL-4. Our data also show that sucralfate is capable
of inducing expression of the regulatory cytokine IL-4 and the suppression of
apoptotic events triggered in gastric mucosa by the increase in TNF-alpha that is
elicited by H. pylori lipopolysaccharide.
PMID- 9759946
TI - Infection with Helicobacter pylori expressing the cagA gene is not associated
with an increased risk of developing peptic ulcer diseases in Korean patients.
AB - BACKGROUND: Helicobacter pylori strains possessing the cagA gene have been
postulated to have a disease-specific relationship to peptic ulcer. The purpose
of this study was to investigate the relationship between the infection with
Helicobacter pylori expressing the cagA gene and the development of peptic ulcer
diseases in Korean patients. METHODS: Genomic DNA and bacterial mRNA in the
gastric mucosa were amplified by polymerase chain reaction (PCR) and reverse
transcription PCR, using synthetic oligonucleotide primers to cagA genes to
compare the prevalence of cagA genes in 35 patients with non-ulcer gastritis and
99 patients with gastric or duodenal ulcer disease (53 and 46, respectively). Two
different primer sets for the cagA gene were used. The first primer set amplified
a 298-bp region (nucleotides 1751-2048), and the second set amplified a 349-bp
region (nucleotides 1228-1249). RESULTS: The expected 298 and 349-bp PCR
amplicons were identified as follows: 1) 32 (91.4%) and 30 (85.7%) of 35 non
ulcer gastritis patients; 2) 5 1 (96.2%) and 50 (94.3%) of 53 benign gastric
ulcer patients; and 3) 46 (100.0%) and 40 (87.0%) of 46 duodenal ulcer patients,
respectively. CONCLUSION: These results strongly suggest that the cagA gene will
not prove to be a useful marker to distinguish disease-specific H. pylori strains
in the development of peptic ulcer diseases in Korean patients.
PMID- 9759947
TI - National surveillance of Helicobacter pylori eradication therapy in Denmark.
Results from registration of 34,582 prescriptions.
AB - BACKGROUND: We wanted to characterize the use of Helicobacter pylori eradication
therapy in Denmark (5,227,862 inhabitants). METHODS: All H. pylori eradication
treatments from a nationwide database including all redeemed drug prescriptions
in the period January 1994 to June 1996 were identified. So were all outpatients
receiving a drug prescription for H. pylori eradication. RESULTS: We recorded
34,582 prescriptions for H. pylori eradication therapy given to 28,784 patients.
The incidence of new consumers was 220 per 10(5) inhabitants per year, with a
maximum at 70-79 years of age. Eighty-six per cent of the patients had only one
treatment course. In 16% of the eradication therapies, nonsteroid anti
inflammatory drugs had been prescribed within the previous 3 months, and 45% had
an anti-ulcer drug prescribed 1-12 months after the H. pylori eradication
therapy. Consumption of antibiotics used for H. pylori eradication accounted for
1.4% of the total consumption of antibiotics. CONCLUSIONS: The incidence of H.
pylori eradication therapy was fairly stable but with changes in the pattern of
drug regimens used. Anti-ulcer drugs were often given after H. pylori eradication
therapy, suggesting an inappropriate use of treatment.
PMID- 9759948
TI - Quality of life of adult coeliac patients treated for 10 years.
AB - BACKGROUND: For patients with coeliac disease, adherence to a gluten-free diet
(GFD) is essential to restore the intestinal mucosa. It is less clear whether
this ensures well-being of the patient. We have therefore assessed aspects of the
quality of life of adult coeliac patients who had been on a GFD for 10 years.
METHODS: By means of the Short Form 36 Health Survey (SF-36), the subjective
health status was measured in 89 adult coeliac patients (61% women) aged 35-74
years. Patients shown to be in histologic remission (n=60) were evaluated by
means of the Gastrointestinal Symptom Rating Scale (GSRS). RESULTS: The coeliac
patients scored significantly lower in the SF-36 than general population, notably
within the General Health and Vitality domains. The low scoring was confined to
the female patients, who also reported significantly more gastrointestinal
symptoms in the GSRS than the male coeliacs. The functional status and perceived
health of the coeliac patients appeared unrelated to their biopsy findings.
CONCLUSIONS: After 10 years on a GFD adult coeliac patients fail to attain the
same degree of subjective health as the general population. This is particularly
true for female patients and suggests that factors beyond normalization of the
intestinal mucosa are of importance for the perceived health status of coeliacs
diagnosed in adult life.
PMID- 9759949
TI - Children with celiac disease express inducible nitric oxide synthase in the small
intestine during gluten challenge.
AB - BACKGROUND: Childhood celiac disease in Sweden is presently seen at an incidence
of around 1/250 and is thus one of the commonest chronic diseases in children. It
has recently been shown that children with untreated celiac disease have
increased levels of nitrate/nitrite in the urine, most likely reflecting an
increased production of nitric oxide in the inflamed mucosa. Nitric oxide is
produced from L-arginine by an inducible or a constitutive nitric oxide synthase.
The inducible nitric oxide synthase (iNOS) can be stimulated in various cells by,
for instance, inflammatory mediators. The present study has been done to find a
possible source of nitric oxide in the small intestine that could result in the
increased levels of nitrate/nitrite in the urine in children with active celiac
disease. METHODS: Small-intestinal biopsy specimens from children with active
celiac disease were labeled with rabbit-anti-human antibodies to iNOS and
visualized with fluorescent pig anti-rabbit antibodies. The specimens were then
analyzed with confocal microscopy to assess the labeling pattern. RESULTS: In all
of seven specimens from children with increased levels of nitrate/nitrite in the
urine, we detected antibodies to iNOS, whereas in five of six control specimens-
that is, from children with normal nitrate/nitrite levels--we could not detect
any iNOS. CONCLUSIONS: Children with active celiac disease have a gluten-induced
nitric oxide production in the small intestine reflected by increased urine
levels of nitrate/nitrite and iNOS expression in the intestine. We conclude that
the increased production of nitric oxide could presumably, directly or
indirectly, result in injury of the small-intestinal tissue.
PMID- 9759950
TI - Small-bowel mucosal inflammation in reticulin or gliadin antibody-positive
patients without villous atrophy.
AB - BACKGROUND: We investigated whether individuals with positive coeliac disease
antibodies but without small-bowel villous atrophy have mucosal inflammation
implicating gluten-sensitivity. METHODS: Small-bowel mucosal morphology; CD3+,
alphabeta+, and gammadelta+ T-cell receptor-bearing intraepithelial lymphocytes;
and mucosal HLA-DR expression were studied in 96 IgA-class antireticulin or
antigliadin antibody-positive adults suspected of having coeliac disease and in
27 control subjects. RESULTS: Villous atrophy compatible with coeliac disease was
found in altogether 29 patients, in 18 of 21 (86%) patients with both
antireticulin and antigliadin antibodies, in 9 of 15 (60%) patients with
antireticulin antibodies only, and in 2 of 60 (3%) with antigliadin antibodies
only. In 67 antibody-positive patients with normal villous architecture the
densities of CD3+, alphabeta+, and gammadelta+ intraepithelial lymphocytes were
significantly higher than in non-coeliac control subjects. Ten patients with
initially increased densities of gammadelta+ T cells but normal villous structure
underwent a follow-up biopsy after 4-18 months, which showed villous atrophy in
five patients. CONCLUSIONS: IgA-class antireticulin or antigliadin antibody
positive patients with normal small-bowel mucosal morphology frequently have
immunohistochemical markers of coeliac disease latency. Together with our follow
up data this implies that they may be gluten-sensitive.
PMID- 9759951
TI - A prospective study of anal sphincter injury due to childbirth.
AB - BACKGROUND: Faecal incontinence commonly affects women, principally because of
childbirth. Our aims were to determine the functional effect of childbirth on the
pressures generated by the anal sphincter and to determine the patterns of injury
to the sphincter. METHODS: Anal manometry was performed in 53 primiparous women
prenatally, in 50 women at a median of 5 weeks postnatally, and repeated in 26
women at a median of 6 months postnatally. In addition, anal ultrasound was
performed postnatally. Pelvic floor symptoms were assessed. The mode of delivery
was examined to determine what variables affected anal function. RESULTS: Squeeze
pressure was significantly reduced (P < 0.001) 6 weeks postnatally (mean, 170.4
cm H2O; standard deviation (s), 56) compared with the prenatal value (mean, 225.6
cm H2O; s, 58). This occurred in symptomatic and asymptomatic women and in women
with a normal anal ultrasound. Resting pressure was significantly reduced at 6
weeks (P < 0.001; prenatal mean, 91.6 cm H2O; s, 25; postnatal mean, 80.Ocm H2O;
s, 21). Delivery method (vaginal or caesarean) was the only factor significant
for the reduced squeeze pressure (r=53.377; standard error, 13.973; P < 0.001).
Sphincter defects (41%) were common but did not influence anal sphincter
function. CONCLUSION: Anal function was significantly affected by vaginal
delivery with short-duration follow-up. This occurred with and without evidence
of an anal sphincter injury. The importance of a sphincter injury is questioned.
PMID- 9759952
TI - Body composition by dual-energy X-ray absorptiometry in patients with Crohn's
disease.
AB - BACKGROUND: To study body composition at the whole-body level in patients with
Crohn's disease and a history of intestinal resection compared with healthy
controls, we performed a cross-sectional study using dual-energy X-ray
absorptiometry (DXA). METHODS: Thirty-one patients, 13 men and 18 women, were
included. They had a history of Crohn's disease for a mean period of 20 years
(range, 4-45 years). All patients had undergone intestinal resections. The colon
had been resected in 24 patients, and the mean length of the resected small
intestine was 97 cm (range, 0-305 cm). At the time of investigation the Crohn's
disease had been in remission for at least 24 months. Patients presented with
significantly increased faecal volume and faecal fat excretion. A group of 69
women and 19 men were investigated with DXA and used as reference group. The fat
free mass (FFM), fat mass (FM), percentage fat mass (FM%), and total body mineral
content (TBMC) were measured by DXA, and the results were expressed as a z-score.
RESULTS: The mean z-score of the body mass index (BMI) was significantly reduced
to -0.35 (P=0.036). The FFM was significantly reduced with a mean z-score of
1.74 (P=0.0001). The FM was unchanged (z-score, 0.12; P=0.42). However, FM
expressed as percentage of body weight was significantly increased, with a z
score of 0.88 (P=0.001). The TBMC was significantly decreased, with a mean z
score of -1.42 (P=0.0001). There was positive direct correlation between the BMI
and TBMC z-scores. There was no correlation between malabsorption and body
composition variables. CONCLUSION: Patients with clinically quiescent Crohn's
disease showed significant changes in body composition, with low BMI, significant
loss of FFM, and unchanged FM. However, when expressed as percentage of body
weight, FM was significantly increased. The TBMC was significantly reduced.
PMID- 9759953
TI - The inflammatory bowel disease questionnaire: a valid and reliable measure in
ulcerative colitis patients in the North East of England.
AB - BACKGROUND: The validity and reliability of the Inflammatory Bowel Disease
Questionnaire (IBDQ) needed to be confirmed before its use in the UK. METHODS:
The IBDQ was administered to 28 subjects with ulcerative colitis (UC) on 3
separate occasions over a period of 4 weeks, twice by an interviewer and once by
self-completion. Convergent and concurrent validity was assessed by using the
Colitis Activity Index (CAI) and the Short Form 36 Health Survey (SF-36). Test
retest reliability and internal consistency were also tested. RESULTS: There were
moderately high Pearson correlations between related IBDQ domains and SF-36
dimensions and also between the CAI score and the IBDQ Bowel domain and the SF-36
Pain dimension. Cronbach's alpha, corrected item-total correlations, and intra
class correlation coefficients were high. CONCLUSIONS: The IBDQ is a valid and
reliable health-related quality of life scale for use in patients with UC and is
suitable for use in the UK.
PMID- 9759954
TI - An orally administered growth factor extract derived from bovine whey suppresses
breath ethane in colitic rats.
AB - BACKGROUND: Lipid peroxidation is a potential mechanism of bowel damage in
colitis. The effect of oral consumption of a bovine whey-derived growth factor
extract (WGFE) on lipid peroxidation was assessed using the ethane breath test in
the dextran sulphate sodium (DSS) model of ulcerative colitis (UC) in rats.
METHODS: Groups of rats consumed water (control), 2% DSS in drinking water, 2%
DSS with a WGFE-supplemented diet, or 2% DSS plus prednisolone (1 mg x kg(-1) x
day(-1)) for 6 weeks, changing to sulphasalazine (100 mg x kg(-1) x day(-1)) for
the subsequent 4 weeks. Ethane breath tests were conducted on all animals on days
2, 4, 6, 8, and 10 (acute phase) and weeks 3, 6, and 9 (chronic phase) after
commencement of DSS consumption. RESULTS: There were no significant differences
in ethane production between any groups during the acute phase. Ethane was
significantly increased (P < 0.05) in rats consuming DSS alone in week 6 compared
with control but had decreased to control levels by week 9. WGFE and conventional
therapy were effective in suppressing ethane production in week 3. CONCLUSIONS:
WGFE is as effective as conventional therapies at limiting ethane production and
thus ostensibly colonic lipid peroxidation in the early phases of experimental
chronic UC.
PMID- 9759955
TI - Mucosal mitochondrial function and antioxidant defences in patients with gastric
carcinoma.
AB - BACKGROUND: Cancer cells have alterations in energy metabolism due to defective
mitochondrial function. This may be due to generation of excessive free radicals
and/or defective antioxidant enzyme systems. The aim of the present study was to
assess mitochondrial function and antioxidant defences in the gastric mucosa of
patients with gastric carcinoma (CA). METHODS: Gastric mucosal mitochondrial
function was assessed by means of the reduction of tetrazolium dye (MTT), and
levels of antioxidants such as glutathione S-transferase (GST), catalase,
superoxide dismutase (SOD), and thiols were measured in biopsy specimens taken
from the tumour mucosa (TM) and tumour-free (TF) mucosa, 2 cm away from the
tumour, in 49 patients with gastric CA and compared with that in 54 controls. In
a further 10 patients with gastric CA, these studies were done on TM and TF
mucosa 2 cm and > or = 5 cm away from the tumour. In 10 patients and 5 controls,
specimens were obtained for electron microscopy as well. Helicobacter pylori
infection was diagnosed by means of histology. RESULTS: MTT reduction and GST and
SOD activities were significantly decreased in TM and TF mucosa in patients with
CA compared with controls (P < 0.01). The levels of thiols and catalase activity
were significantly increased in CA as compared with controls (P < 0.01). H.
pylori positivity did not influence most of these variables but did give
significant decrease in MTT reduction in CA (TF) mucosa (P=0.01) and significant
increase in thiol levels in CA (TM) mucosa (P=0.04). Electron microscopy showed
mitochondrial alterations in tumour cells in all patients and in adjacent mucosa
of 10%-50% of the cells. CONCLUSIONS: 1) In gastric CA the cancer mucosal cells
and the non-involved cells adjacent to the tumour have defective mitochondrial
function, which may be due to altered antioxidant defences and possibly altered
free radical formation. 2) Ultrastructural mitochondrial abnormalities are shown
to parallel these biochemical abnormalities.
PMID- 9759956
TI - Pain patterns after distension of the gallbladder in patients with acute
cholecystitis.
AB - BACKGROUND: Visceral pain is characterized by poor pain localization and a
referred or radiating pain pattern. Its clinical importance in the abdomen is
stressed by the finding that about one-third of patients still complain of
abdominal pain after cholecystectomy. A better understanding of symptoms arising
from the gallbladder and the underlying pathophysiology is therefore desirable.
The aim of the present study was consequently primarily to characterize the
symptom patterns after distension of the gallbladder. Secondary aims were to
describe the pressure-volume relation in the gallbladder and the cystic duct
opening pressure. METHODS: Twelve patients (nine women, three men) treated with
cholecystostomy for acute cholecystitis were investigated. Simultaneous
cholescintigraphy and measurement of changes in intraluminal gallbladder pressure
after injections of saline through a gallbladder catheter were performed. After
each injection of saline the localization of pain and the presence of nausea and
vomiting were registered. The injections continued until the patient felt
abdominal pain necessitating cessation of the investigation or until the cystic
duct opened (visualized on cholescintigraphy). RESULTS: Distension of the
gallbladder caused pain in 10 of the 12 patients. In 70% the pain was localized
under the right costal margin or in the epigastrium. No mathematical formula
could describe the pressure-volume relation in the gallbladder. The cystic duct
opening pressure varied between 3 and 44 mmHg. CONCLUSIONS: Pain caused by
increased gallbladder pressure is localized mostly, but not always, under the
right curvature and in the epigastrium. A substantial variation in cystic duct
opening pressure was found.
PMID- 9759957
TI - Prevalence of intrapulmonary vascular dilatations in normoxaemic patients with
early liver cirrhosis.
AB - BACKGROUND: The aim of this study was to determine the prevalence of
intrapulmonary vascular dilatations (IPVD) in normoxaemic patients with early
liver cirrhosis and to compare their occurrence in progressive alcoholic versus
postviral hepatic insufficiency. METHODS: Pulmonary function tests and arterial
blood gas measurements were performed in 75 consecutive patients with cirrhosis
of alcoholic and postviral aetiology. Contrast-enhanced echocardiography was used
to identify IPVD. RESULTS: All patients were grade A or B in accordance with the
Child-Pugh modified classification. Arterial blood gas analyses showed
normoxaemia in all patients. Eight of 75 patients (10.7%) had a positive contrast
echocardiogram, all with a decreased diffusion capacity (D1CO < 75% of the
expected value). The abnormality was more prominent with advancing stage of liver
failure (4.5% in grade A versus 19.4% in grade B; P < 0.05) and more common in
patients with alcoholic cirrhosis (17.5% in alcoholic versus 2.9% in postviral
cirrhosis; P < 0.05). CONCLUSION: In normoxaemic patients with early liver
cirrhosis subclinical pulmonary vasodilatation, as assessed with contrast
echocardiography, can occur. The finding is more prominent in alcoholic cirrhosis
and possibly reflects an advancing degree of liver insufficiency.
PMID- 9759958
TI - Gallbladder contents and fasting gallbladder volumes during and after pregnancy.
AB - BACKGROUND: A high risk of developing sludge or gallstones has been associated
with pregnancy. The aim of this study was to relate the prevalence of sludge and
gallstones during and shortly after pregnancy to fasting gallbladder volume as an
indicator of gallbladder motility. METHODS: The population included 114
apparently healthy pregnant women from the Outpatient Clinic of Obstetrics of a
large regional hospital and from the practices of regional midwives.
Ultrasonography of the gallbladder was performed at weeks 15, 25, and 35 of
gestation and at week 3 and month 6 postpartum. RESULTS: At gestational week 15,
3 women had gallstones and 10 had sludge (mean volume, 33.8 ml), and 99 women had
a normal gallbladder (mean volume, 30.5 ml). At week 25, 1 woman with a normal
gallbladder formed gallstones and underwent cholecystectomy shortly after, and 22
women had sludge, of whom 13 had a normal gallbladder at first examination (mean
volume, 33.2 ml). In 88 women with normal gallbladders (of whom 2 had sludge at
week 15) mean volume was 31.9 ml. At week 35, 2 women had gallstones, and 21 had
sludge (mean volume, 30.5 ml). In the remaining 79 women the gallbladders were
clear (mean volume, 29.5 ml). Eight women developed sludge and two women
gallstones in normal gallbladders at week 25. Seven women with sludge at week 25
had a normal gallbladder at week 35. Three weeks postpartum only 10 of 100 women
had sludge (mean volume, 29.1 ml). Of these 10, 9 women had a normal gallbladder
at week 35. Twenty of 21 women with sludge at week 35 had normal gallbladders
week 3 postpartum. Gallstones found at week 35 had disappeared. In the women with
a normal gallbladder the mean volume was decreased to 19.7 ml (P < 0.0001). Six
months postpartum, sludge was found in 6 (mean volume, 18.4 ml) of 93 women (mean
volume, 20.3 ml), of whom 5 had a normal gallbladder at week 3 postpartum. Only
61 women showed a normal gallbladder at each examination of the study. No
differences in patient characteristics were found between women with normal
gallbladders and those with sludge or gallstones. CONCLUSIONS: Fasting
gallbladder volume was increased in all pregnant women. This could not explain
the formation of sludge or gallstones during gestation. Decrement of gallbladder
volumes after delivery was faster in normal, clear gallbladders. More than a
prerequisite, increased fasting gallbladder volume seemed to be a permissive
factor of pregnancy-associated gallstone formation.
PMID- 9759960
TI - Delayed mid-ileal perforation secondary to acute-on-chronic ischaemia after a
diagnostic colonoscopy.
AB - Perforation occurring at a remote site of the bowel after diagnostic colonoscopy
is rare. A 61-year-old man presenting with bloody diarrhoea underwent
colonoscopy. A dynamic ileus developed in less than 1 day, and mid-ileal
perforation occurred 7 days after the procedure. It is suggested that high air
pressure during colonoscopy further compromised the reduced blood flow in the mid
ileum, which had underlying chronic ischaemia, leading to perforation. Our
patient constitutes the first reported case of small-bowel perforation after
colonoscopy due to pre-existent ileal ischaemia.
PMID- 9759959
TI - Serum pancreatic enzymes in human immunodeficiency virus-infected children. A
collaborative study of the Italian Society of Pediatric Gastroenterology and
Hepatology.
AB - BACKGROUND: Numerous studies have shown pancreatic disease in adult human
immunodeficiency virus (HIV)-infected patients, but there are very few reports on
pediatric patients. Our aim was to determine the prevalence of increased serum
pancreatic enzyme levels and their relationship to clinical manifestations of
acute pancreatitis in HIV-infected children. METHODS: Forty-seven consecutive,
symptomatic HIV-infected children (24 male; median age, 7.3 years; range, 1-17
years) and 45 sex- and age-matched controls without gastroenterologic disease
were enrolled. In all subjects serum total amylase, pancreatic amylase, and
lipase were assayed with commercial kits. The following were recorded: disease
progression (CDC class), nutritional status (weight Z-score), CD4 lymphocyte
count, drug treatment during the previous 12 months, presence of opportunistic
infections, clinical evidence of acute pancreatitis (increased serum pancreatic
enzymes associated with vomiting, abdominal distention, and intolerance when
eating). RESULTS: Ten of 47 HIV patients had increased serum total amylase
values; however fewer patients had increased specific pancreatic enzymes: 6 of 47
for pancreatic amylase (range, 1.8- to 19.8-fold normal limit) and 7 of 47 for
lipase (range, 1.4- to 4-fold normal limit). Values were normal in all controls.
Two HIV patients with increased total amylase had clinically evident parotid
inflammation. None of the patients with increased serum pancreatic amylase and/or
lipase had clinical symptoms of acute pancreatitis. Regression analysis showed no
correlation between increased serum pancreatic enzyme levels and disease
progression (CDC class), immunologic status (CD4 count), nutritional status, drug
administration, or opportunistic infections. CONCLUSIONS: Fifteen per cent of HIV
infected children had biochemical evidence of pancreatic involvement; however,
this condition was unrelated to clinical signs of pancreatitis. Neither drug
administration nor opportunistic infections seem to determine the increased serum
pancreatic enzyme levels.
PMID- 9759961
TI - Helicobacter pylori infection and progression of gastric atrophy and intestinal
metaplasia.
PMID- 9759962
TI - Percutaneous ethanol injection therapy for hepatocellular carcinoma in patients
with ascites.
PMID- 9759963
TI - The cell division cycle and the pathophysiology of Alzheimer's disease.
AB - Evidence is growing of a role of apoptosis in neurodegenerative disorders
including Alzheimer's disease. Recent research indicates that cell cycle
disturbances may promote apoptosis in neurodegenerative diseases. In this
commentary we will discuss the control of the cell cycle in mammalian cells in
general and in the central nervous system in particular. We then summarize the
evidence for cell cycle perturbations in Alzheimer's disease and discuss the
possible significance these may have for the development of pathological changes
in this disease. Our working hypothesis is that, contrary to previous belief,
neurons in the adult human brain are capable of re-entering the cell division
cycle. The progression of the cell cycle is normally arrested at an early stage
and neurons are able to re-differentiate. However, in Alzheimer's disease the
cell cycle is allowed to progress into the G2 phase. At this stage re
differentiation is not possible and the neurons will suffer one of two fates:
either they will die via an apoptotic pathway or they may produce Alzheimer-type
pathology.
PMID- 9759964
TI - The spike trains of inhibited pacemaker neurons seen through the magnifying glass
of nonlinear analyses.
AB - This communication describes the new information that may be obtained by applying
nonlinear analytical techniques to neurobiological time-series. Specifically, we
consider the sequence of interspike intervals Ti (the "timing") of trains
recorded from synaptically inhibited crayfish pacemaker neurons. As reported
earlier, different postsynaptic spike train forms (sets of timings with shared
properties) are generated by varying the average rate and/or pattern (implying
interval dispersions and sequences) of presynaptic spike trains. When the
presynaptic train is Poisson (independent exponentially distributed intervals),
the form is "Poisson-driven" (unperturbed and lengthened intervals succeed each
other irregularly). When presynaptic trains are pacemaker (intervals practically
equal), forms are either "p:q locked" (intervals repeat periodically),
"intermittent" (mostly almost locked but disrupted irregularly), "phase walk
throughs" (intermittencies with briefer regular portions), or "messy" (difficult
to predict or describe succinctly). Messy trains are either "erratic" (some
intervals natural and others lengthened irregularly) or "stammerings" (intervals
are integral multiples of presynaptic intervals). The individual spike train
forms were analysed using attractor reconstruction methods based on the lagged
coordinates provided by successive intervals from the time-series Ti. Numerous
models were evaluated in terms of their predictive performance by a trial-and
error procedure: the most successful model was taken as best reflecting the true
nature of the system's attractor. Each form was characterized in terms of its
dimensionality, nonlinearity and predictability. (1) The dimensionality of the
underlying dynamical attractor was estimated by the minimum number of variables
(coordinates Ti) required to model acceptably the system's dynamics, i.e. by the
system's degrees of freedom. Each model tested was based on a different number of
Ti; the smallest number whose predictions were judged successful provided the
best integer approximation of the attractor's true dimension (not necessarily an
integer). Dimensionalities from three to five provided acceptable fits. (2) The
degree of nonlinearity was estimated by: (i) comparing the correlations between
experimental results and data from linear and nonlinear models, and (ii) tuning
model nonlinearity via a distance-weighting function and identifying the either
local or global neighborhood size. Lockings were compatible with linear models
and stammerings were marginal; nonlinear models were best for Poisson-driven,
intermittent and erratic forms. (3) Finally, prediction accuracy was plotted
against increasingly long sequences of intervals forecast: the accuracies for
Poisson-driven, locked and stammering forms were invariant, revealing
irregularities due to uncorrelated noise, but those of intermittent and messy
erratic forms decayed rapidly, indicating an underlying deterministic process.
The excellent reconstructions possible for messy erratic and for some
intermittent forms are especially significant because of their relatively low
dimensionality (around 4), high degree of nonlinearity and prediction decay with
time. This is characteristic of chaotic systems, and provides evidence that
nonlinear couplings between relatively few variables are the major source of the
apparent complexity seen in these cases. This demonstration of different
dimensions, degrees of nonlinearity and predictabilities provides rigorous
support for the categorization of different synaptically driven discharge forms
proposed earlier on the basis of more heuristic criteria. This has significant
implications. (1) It demonstrates that heterogeneous postsynaptic forms can
indeed be induced by manipulating a few presynaptic variables. (2) Each
presynaptic timing induces a form with characteristic dimensionality, thus
breaking up the preparation into subsystems such that the physical variables in
each operate as one
PMID- 9759965
TI - Cellular mechanisms underlying two muscarinic receptor-mediated depolarizing
responses in relay cells of the rat lateral geniculate nucleus.
AB - We used the whole-cell recording technique in an in vitro preparation to examine
the electrophysiological actions of the muscarinic receptors on relay cells in
the rat lateral geniculate nucleus. Drop application of the muscarinic agonist
acetyl-beta-methylcholine resulted in a slow depolarization that persisted for
several minutes. The response was insensitive to the nicotinic antagonist
hexamethonium, but was blocked by atropine, a muscarinic antagonist. The response
was also insensitive to blockade of synaptic transmission by tetrodotoxin,
indicating a direct muscarinic effect. The muscarinic depolarization consisted of
two components that were somewhat separated in time. The early portion of the
muscarinic response was mediated by a large inward current with little change in
input resistance, while the later portion was mediated by a small inward current
associated with a large increase in input resistance. Pharmacological agents were
used to distinguish the two components. Drop application of McN-A-343, an ml
receptor agonist, could only mimic the later component of the muscarinic
response. This was supported by the result that the later component was blocked
by low concentrations of pirenzepine. These data suggest that the ml receptor
only mediates the late component of the muscarinic response, while the early
component is mainly mediated by the m3 receptor. The idea that both ml and m3
receptors were involved in the muscarinic depolarization was further supported by
voltage-clamp analysis. This revealed that activation of the ml receptor was
associated with a decrease in an inward potassium current, IKleak, while
activation of the m3 receptor was likely associated with both a decrease in
IKleak and an increase in the hyperpolarization-activated cation current Ih. In
summary, our data suggest that muscarinic responses in geniculate relay cells
result from the activation of two receptors, which modulate IKleak and Ih. Given
the fact that the ascending aminergic systems also depolarize geniculate relay
cells via two receptors acting on IKleak and Ih, we concluded that ascending
activating systems use common mechanisms to enact the depolarizing form of
arousal in relay neurons.
PMID- 9759966
TI - Cholinergic excitation of dendrites in neocortical neurons.
AB - Discharge patterns were studied in response to iontophoretic application of
acetylcholine to the soma and dendrites of 128 neocortical pyramidal neurons of
layer V. Extracellular recordings were obtained from slices of the guinea-pig
parietal cortex. All responses found were excitatory and were better expressed in
spontaneously firing cells than in silent ones. Sensitivity to acetylcholine was
approximately the same at somatic and dendritic sites in all the cells.
Activation of muscarinic receptors gave rise to firing patterns with equal
latencies and intensities when applied to both soma and dendrites. The latter
suggests that membrane excitation elicited in dendrites by binding of
acetylcholine to muscarinic cholinoreceptors is likely to propagate towards the
soma through intracellular biochemical processes. Modulating effect of
acetylcholine on output firing patterns, elicited by dendritic application of
excitatory amino acids, included shortening of the somatic response latency and
increase of response intensity and duration. We propose that, in contrast to
glutamatergic excitation, the spread of cholinergic excitation along dendrites
involves intra-cellular chemical signalling and results in changing the
electrical properties of dendrites all over their length.
PMID- 9759968
TI - Multiple picrotoxinin effect on glycine channels in rat hippocampal neurons.
AB - The effect of picrotoxinin on glycine-induced chloride currents was studied in
dissociated rat hippocampal neuron culture in whole-cell and excised outside-out
patches. Picrotoxinin blocked the glycine induced chloride currents. The
picrotoxinin effect at 20 microM on glycine dose response relationship suggested
a competitive mechanism. However, at 1 mM, the picrotoxinin effect was largely
noncompetitive. In excised patches, glycine activated two types of channels
distinguished by a difference in conductances. The first group had single channel
conductances of around 47 pS and another around 100 pS. Occasionally, both types
of channels were found in the same excised patch. Low concentration of
picrotoxinin selectively blocked large conductance channels. At higher
concentrations of 0.5 to 1 mM, picrotoxinin blocked the small conductance
channels by a flickering block. These findings indicate that the whole-cell
glycine current in rat hippocampal neurons is mediated by at least two types of
channels. The two types of channels have distinct conductance, picrotoxinin
sensitivity and different mechanism of picrotoxinin block.
PMID- 9759967
TI - Histamine modulates high-voltage-activated calcium channels in neurons
dissociated from the rat tuberomammillary nucleus.
AB - The effects of histamine on high-voltage-activated Ca2+ channels in the
histaminergic neurons acutely dissociated from the rat tuberomammillary nucleus
were investigated in the nystatin-perforated patch recording mode under voltage
clamp conditions. Histamine suppressed the high-voltage-activated Ca2+ channel
currents in neurons which were positive for histidine decarboxylase with
immunocytochemistry. The half-maximum inhibitory concentration and maximum
inhibition were 2.6 x 10(-7) M and 16.6+/-1.90%, respectively. An H3 receptor
agonist, R(-)-alpha-methylhistamine, mimicked the response to histamine, and
thioperamide, an H3 receptor antagonist, inhibited the response to histamine. On
the other hand, neither 2-methylhistamine, an H1 receptor agonist, nor dimaprit,
an H2 receptor agonist, had a significant effect on the Ca2+ channel currents.
Pretreatment with pertussis toxin blocked the inhibitory effect of histamine on
Ca2+ channels, suggesting the involvement of Gi/Go proteins in the action of
histamine. Omega-conotoxin-GVIA, omega-agatoxin-IVA, nicardipine, and omega
conotoxin-MVIIC blocked the high-voltage-activated Ca2+ channel currents by 15.6,
4.3, 27.1, and 31.2% of the total current, respectively, suggesting the existence
of N-, P-, L-, and Q-type Ca2+ channels. A current that was insensitive to these
blockers was also found. This residual current, "R-type", was completely
suppressed by the addition of 200 microM Cd2+. Histamine significantly inhibited
both the N- and P-type current components among these five types of Ca2+ channel
currents. We concluded that histamine suppresses the N- and P-type Ca2+ channels
in histaminergic neurons through an H3 receptor which is linked to a pertussis
toxin-sensitive G-protein.
PMID- 9759969
TI - The effects of 17beta-estradiol on ischemia-induced neuronal damage in the gerbil
hippocampus.
AB - The effects of 17beta-estradiol, a potent estrogen, on ischemia-induced neuronal
damage, membrane depolarization and changes in intracellular Ca2+ concentration
were studied in gerbil hippocampi. The histological outcome evaluated seven days
after 3 min of transient forebrain ischemia in hippocampal CA1 pyramidal cells
was improved by high doses of 17beta-estradiol (30 microg, i.c.v. and 4 mg/kg,
i.p.), whereas low doses of 17beta-estradiol (3 and 10 microg, i.c.v.) showed no
protective effect. Administration of 17beta-estradiol did not affect the changes
in the direct current potential shift in ischemia in the hippocampal CA1 area at
any dosage. A hypoxia-induced intracellular Ca2+ increase was evaluated by in
vitro microfluorometry in gerbil hippocampal slices. Pretreatment of 17beta
estradiol (4 mg/kg, injected i.p. 1 h before decapitation) suppressed the
increase in the intracellular concentration of Ca2+ due to the in vitro hypoxia,
affecting both the onset of the increase and the extent. The in vitro hypoxia in
the Ca2+-free condition induced an elevation of the intracellular concentration
of Ca2+, although the increase was gradual. Pretreatment of 17beta-estradiol (4
mg/kg, i.p.) also inhibited this elevation. These findings imply that high doses
of 17beta-estradiol protect the neurons from ischemia by inhibiting the release
of Ca2+ from the intracellular Ca2+ stores, as well as by inhibiting the influx
of Ca2+ from the extracellular space.
PMID- 9759970
TI - Phencyclidine interferes with the hippocampal gating of nucleus accumbens
neuronal activity in vivo.
AB - The N-methyl-D-aspartate channel blocker phencyclidine is known to induce
psychotic episodes in normal subjects and exacerbate psychosis in schizophrenics;
however, its site of action is not clear. The prefrontal cortex, hippocampus, and
basal ganglia are brain regions that appear to play a role in the pathophysiology
of schizophrenia, and therefore are the most likely to be involved in the
psychotomimetic action of phencyclidine. In this study, systemic administration
of phencyclidine reduced the frequency and duration of the spontaneously
occurring depolarized plateaus observed in the membrane potential of accumbens
neurons recorded intracellularly in vivo. Furthermore, recordings from rats
pretreated with phencyclidine yielded proportionately fewer neurons showing
depolarized events compared with untreated animals. These results suggest that
phencyclidine may interfere with the generation of the depolarized ("up") state
of the accumbens neuron membrane potential, which we had previously shown is
dependent upon hippocampal input and is necessary for action potential discharge
in these neurons. This action of phencyclidine is proposed to impair the flow of
cortical information through the nucleus accumbens, and thereby mimic the
consequences of the hippocampal deficit proposed to contribute to the
pathophysiology of schizophrenia.
PMID- 9759971
TI - Axotomy-induced c-JUN expression in young medial septal neurons is regulated by
nerve growth factor.
AB - In the present study we investigated the axotomy-induced expression of the proto
oncogene c-jun in young rat medial septal neurons and its regulation by nerve
growth factor. First, medial septal neurons were retrogradely labelled by Fast
Blue injection into the hippocampus at postnatal day 1 (P1). Rats of different
developmental ages (P6, P9, P14, P21, P28 and P42) were then subjected to
bilateral fimbria-fornix transection resulting in the axotomy of septohippocampal
projection neurons. After the lesion, c-JUN immunoreactivity was observed in the
nuclei of axotomized medial septal neurons of all stages examined, suggesting
that c-JUN induction is an age-independent feature of axotomized medial septal
neurons. Double immunolabelling for choline acetyltransferase and c-JUN or
parvalbumin and c-JUN, respectively, revealed that both cholinergic and GABAergic
septohippocampal projection neurons express c-JUN after axotomy. In addition, a
co-localization of immunostaining for c-JUN and the neuropeptide galanin was
found after lesion, as both proteins were induced in the same medial septal
neurons following fimbria-fornix transection. Next, the regulation of c-JUN
expression in axotomized medial septal neurons was studied in organotypic
cultures of the medial septum. Axotomized medial septal neurons in culture did
not express c-JUN in contrast to the in vivo situation. With the concept that
nerve growth factor suppresses c-JUN expression, slice cultures of the medial
septum were treated with antibodies against nerve growth factor. This treatment
caused a dose-dependent increase in c-JUN-positive cells in these slice cultures.
Simultaneous addition of nerve growth factor and antibodies against nerve growth
factor resulted in the reversal of this effect. These data suggest an age
independent induction of c-JUN in axotomized medial septal neurons and its
regulation by nerve growth factor.
PMID- 9759972
TI - The non-synaptic expression of transforming growth factor-beta 2 is neurally
regulated and varies between skeletal muscle fibre types.
AB - In adult skeletal muscles, transforming growth factor-beta 2 is restricted to the
postsynaptic domain of the neuromuscular junction. The various putative functions
of this transforming growth factor-beta 2 predict different patterns of
transforming growth factor-beta 2 expression in denervated muscles. We therefore
denervated rat tibialis anterior, extensor digitorum longus and soleus muscles
and examined the expression of transforming growth factor-beta 2 using semi
quantitative reverse-transcription polymerase chain reaction and
immunohistochemistry. Denervation up-regulated transforming growth factor-beta 2
expression extrasynaptically with little or no effect on synaptic expression. The
up-regulation was detectable by one day, had become significant by three days and
remained elevated for at least two weeks. This proves that the transforming
growth factor-beta 2 associated with the neuromuscular junction is not under
neural control and is consistent with transforming growth factor-beta 2 being a
trophic factor for motoneurons. This pattern of transforming growth factor-beta 2
expression is similar to that described for other proteins associated with the
neuromuscular junction, notably the acetylcholine receptor subunit genes.
However, in contrast to the acetylcholine receptor subunit genes, the extent of
up-regulation of transforming growth factor-beta 2 varied between fibre types,
with the glycolytic IIB fibres being less affected than other fibre types.
PMID- 9759973
TI - Direct activation of the high-affinity nerve growth factor receptor by a non
peptide symmetrical polyanion.
AB - The high-affinity nerve growth factor receptor (gp140TrkA) is a tyrosine kinase
receptor. The dimeric ligand, nerve growth factor, activates the receptor by
stabilizing homodimer formation, which initiates transautophosphorylation.
Suramin is a symmetrical planar polyanionic molecule which is being used as a
novel experimental anti-neoplastic agent. Proposed mechanisms of the drug's anti
proliferative activity include blocking mitogenic stimulatory growth factors or
inhibition of tumor-specific cellular enzymes. In PC12 cells and in dorsal root
ganglion neurons, suramin has been shown to act as a partial agonist for
gp140TrkA. We now demonstrate direct activation of gp140TrkA by suramin using in
vitro protein kinase assays and receptor dimerization studies. Additionally,
activation of phosphatidylinositol-3-kinase by suramin and nerve growth factor
was observed with 10-min exposure. The addition of anti-nerve growth factor
antibodies along with suramin did not reduce the level of gp140TrkA
phosphorylation, excluding induction of an autocrine loop of nerve growth factor
release and activation. This demonstrates that a small polyanion can directly
activate gp140TrkA via receptor dimerization. Our study reveals a suramin-induced
homodimerization of gp140TrkA. This finding correlated with significant neurite
outgrowth in naive PC12 cells exposed to the drug. Studies will be initiated to
design structural analogs of suramin which possess neurotrophic properties with
no associated neurotoxicity.
PMID- 9759974
TI - Regulation of a site-specific phosphorylation of the microtubule-associated
protein 2 during the development of cultured neurons.
AB - The phosphorylation state of cytoskeletal proteins, including certain microtubule
associated proteins, may influence the development and plasticity of axons and
dendrites in mammalian neuron in response to appropriate extracellular stimuli.
In particular, high molecular weight microtubule-associated protein 2, has been
implicated in dendrite growth and synaptic plasticity and is thought to be
modulated by phosphorylation and dephosphorylation. We have previously determined
that threonines 1620/1623 on the microtubule-associated protein 2 molecule become
phosphorylated in vivo and are targets for proline-directed protein kinases in
vitro. Using the phosphorylated site-specific antibody 305, we now report the
decreased phosphorylation state of high molecular weight microtubule-associated
protein 2 during the development of cultured cerebellar granule neurons.
Phosphorylation of high molecular weight microtubule-associated protein 2 at this
site is significantly inhibited by lithium in short-term cultured neurons, which
suggests the implication of glycogen synthase kinase-3. In long-term cultured
neurons, it is also partially inhibited by PD098059, an inhibitor of
extracellular signal-regulated protein kinase activation, which indicates an
additional contribution of this kinase to high molecular weight microtubule
associated protein 2 phosphorylation at this stage. Both in short-term and long
term cultured neurons, okadaic acid augments high molecular weight microtubule
associated protein 2 phosphorylation at this site through the inhibition of
protein phosphatases 1 and/or 2A. Finally, glutamate receptor activation leads to
a dephosphorylation of high molecular weight microtubule-associated protein 2 at
this site which can also be effectively prevented by okadaic acid. These results
are consistent with the participation of glycogen synthase kinase-3,
extracellular signal-regulated protein kinases and protein phosphatases 1 and 2A,
in the regulation of microtubule-associated protein 2 phosphorylation within
living neurons, which may be modulated by extracellular signals like the
neurotransmitter glutamate.
PMID- 9759975
TI - Immunohistochemical evidence for dysregulation of the GABAergic system
ipsilateral to photochemically induced cortical infarcts in rats.
AB - Deficits of GABAergic transmission have been reported to occur in tissue
surrounding ischemic cortical lesions between a few days and several weeks after
the insult. In the present experiments, we used immunohistochemistry with
antibodies against parvalbumin and two major subunits of the GABA(A) receptor
(alpha1, alpha2) to characterize the events that underlie these changes at
different levels of circuit organization. Neocortical infarcts (2 mm diameter)
consistently affecting medial parts of the primary somatosensory cortex were
induced photochemically in adult male Wistar rats; animals were allowed to
recover for one week before perfusion-fixation. When compared to controls the
pattern of immunoreactivity had changed for the al subunit of the GABA(A)
receptor seven days after the insult. Ipsilateral to the ischemic lesions, we
found a decrease in staining intensity reaching up to 4 mm laterally, resulting
in a partial or complete absence of the normal laminar staining pattern. No
consistent changes were observed for the alpha2 subunit. Parvalbumin staining
revealed pathological alterations in a rim of tissue surrounding the infarct,
measuring up to 1 mm from the border of the infarcts. Parvalbumin-positive
interneurons in this region showed signs of degeneration; both a reduction of the
number of dendrites and, to a lesser extent and only immediately adjacent to the
ischemic lesions, a reduction of the number of parvalbumin-positive neurons was
readily apparent. The results provide evidence for both a differential regulation
of two GABA(A) receptor subunits and degenerative changes of parvalbumin
containing interneurons ipsilateral to cortical infarcts. The relevance of these
findings for mechanisms underlying long-term recovery, transient functional
deficits and postinfarct seizures warrants further investigation.
PMID- 9759976
TI - The role of nigrostriatal dopamine in metabotropic glutamate agonist-induced
rotation.
AB - Metabotropic glutamate receptors are a major class of excitatory amino acid
receptors. Eight metabotropic glutamate receptors subtypes have been cloned and
have been classified into three groups based on their amino acid sequence
homology, effector systems, and pharmacological profile. Previous results have
shown that striatal group I metabotropic glutamate receptor stimulation produces
vigorous contralateral rotation in intact rats, thought to be due to increased
striatal dopamine release. Examination of FOS-like immunoreactivity and local
cerebral glucose metabolism suggests that this occurs secondary to activation of
the subthalamic nucleus. We sought to determine the contribution of dopamine by
examining metabotropic glutamate receptor agonist-induced rotation in rats
following acute dopamine depletion by reserpine/alpha-methyl-para-tyrosine
treatment, or chronic dopamine depletion by 6-hydroxydopamine treatment. In
unilateral 6-hydroxydopamine lesioned rats, the group I metabotropic glutamate
receptor agonist (RS)-3,5-dihydroxyphenylglycine induced contralateral rotation
with a coincident increase in striatal 3,4-dihydroxyphenylacetic acid. The
rotation was attenuated by the group I antagonist 1-aminoindan-1,5-dicarboxylate.
Examination of FOS-like immunoreactivity and [14C]2-deoxyglucose uptake in
chronically dopamine depleted rats also revealed similar patterns to those seen
previously in intact rats. However, acutely dopamine depleted rats do not exhibit
metabotropic glutamate receptor agonist-induced rotation and show a different
pattern of [14C]2-deoxyglucose uptake, with no increase in glucose utilization in
the intermediate and deep layers of the superior colliculus. These results
suggest that there are compensatory changes under conditions of chronic dopamine
denervation which permit metabotropic glutamate receptor agonist-induced rotation
to occur, which may include dopamine receptor supersensitivity, increased
dopamine turnover, and/or changes in sensitivity of striatal group I metabotropic
glutamate receptors. The group III metabotropic glutamate receptor agonist L-(+)
2-amino-4-phosphonobutyrate induced contralateral rotation in 6-hydroxydopamine
lesioned rats, while it had no effect in intact rats. Additionally, examination
of FOS-like immunoreactivity revealed a distinct pattern following L-(+)-2-amino
4-phosphonobutyrate administration in 6-hydroxydopamine lesioned versus intact
rats. These results suggest that there is a change in the effect of striatal
group III stimulation under conditions of dopamine depletion.
PMID- 9759977
TI - Birth insult increases amphetamine-induced behavioral responses in the adult rat.
AB - We have previously reported that an apparently uncomplicated Caesarean section
birth produces long-term alterations in steady-state levels of dopamine in the
central nervous system of the rat. In addition, adult rats that had been born by
Caesarean section, either with or without acute global anoxia, showed markedly
greater dopamine release from the nucleus accumbens in response to repeated
stress, in comparison to vaginally born controls. The aim of the present study
was to test whether these birth complications also result in long-term changes in
behavior mediated by dopamine systems. For this, we investigated effects of a low
dose (0.5 mg/kg) of amphetamine on activity levels in three-month-old rats that
had been born vaginally (control), by rapid Caesarean section, or by Caesarean
section with 15 min of global anoxia. Amphetamine induced a significantly greater
increase in locomotor activity in animals born by Caesarean section or by
Caesarean section+ 15 min anoxia, in comparison to the drug's effects in
vaginally born controls. Behavioral responses were further analysed from video
recordings of the animals' behavior. In confirmation of automated activity
counts, both animals born by Caesarean section and by Caesarean section + 15 min
anoxia showed a significant increase in the duration and frequency of moving and
a decrease in the duration and frequency of standing, in comparison to vaginally
born controls. Animals delivered by Caesarean section showed a significant
increase in the duration of sniffing and a decrease in the duration and frequency
of grooming when compared to vaginally born controls. Animals delivered by
Caesarean section + 15 min anoxia showed a significant increase in the duration
and frequency of rearing, in comparison to controls. The pattern of behavioral
changes observed indicates that, as adults, animals born by Caesarean section and
by Caesarean section with added global anoxia both show heightened behavioral
responses to amphetamine, in comparison to vaginally born animals. These findings
highlight the sensitivity of dopamine pathways to variations in birth procedure
and add experimental support to epidemiological evidence implicating birth
complications in the pathophysiology of disorders involving central dopaminergic
neurons, such as schizophrenia.
PMID- 9759978
TI - Brain regional substrates for the actions of the novel wake-promoting agent
modafinil in the rat: comparison with amphetamine.
AB - Modafinil is a novel wake-promoting compound for which the mechanism and sites of
action are unknown. We examined the neural substrates in the brain for the
actions of modafinil using 2-deoxyglucose autoradiography and compared the
findings to those obtained with amphetamine. Modafinil showed a relatively
restricted pattern of changes in brain regional metabolic activity, while
amphetamine altered glucose utilization in a wide variety of brain regions. Both
modafinil and amphetamine increased glucose utilization in all subregions of the
hippocampus (subiculum, CA1-CA3 and dentate gyrus) and in the centrolateral
nucleus of the thalamus. Modafinil also increased glucose utilization in the
central nucleus of the amygdala, but amphetamine had no effect in this region.
Brain structures in which amphetamine increased metabolic rate but modafinil had
no effect included regions of the basal ganglia, other nuclei of the thalamus,
the frontal cortex, the nucleus accumbens, the ventral tegmental area and the
pontine reticular fields. These findings suggest that, while both modafinil and
amphetamine promote wakefulness, they act via distinctly different mechanisms.
Modafinil appears to act on a specific subset of brain pathways which regulate
sleep and wakefulness, whereas amphetamine affects a greater number of cerebral
structures involved in the regulation of these behavioral states. Modafinil also
lacks the pronounced effects on the extrapyramidal motor system which are
characteristic of amphetamine and other psychomotor stimulants, implying that the
effects of modafinil are not mediated by the dopamine system and that modafinil
may selectively increase wakefulness with fewer side effects.
PMID- 9759979
TI - Electrical and optical monitoring of alpha-latrotoxin action at Drosophila
neuromuscular junctions.
AB - Electrophysiological recording demonstrates that alpha-latrotoxin, a 125,000 mol.
wt component of black widow spider venom, promotes high frequency quantal
discharges at larval neuromuscular junctions of Drosophila. Concomitantly,
fluorescence imaging of presynaptic calcium ion activity reveals that this toxin
qualitatively elevates cytosolic ionized calcium in this preparation. These
activities of alpha-latrotoxin are selectively antagonized by a monoclonal
antibody, 4C4.1, that was previously shown to inhibit the action of this toxin in
PC-12 cells. However, 4C4.1 does not block the release-promoting activity of gel
filtered extracts of black widow spider venom. This indicates that black widow
spider venom has multiple components that promote quantal transmitter secretion
in invertebrates. This investigation demonstrates that alpha-latrotoxin is among
the active principles in black widow spider venom that enhance transmitter
release and raise cytosolic ionized calcium in Drosophila. These results suggest
that Drosophila, because of the relative ease of genetic manipulation, may be
useful to study the target protein(s) that mediate the binding and action of
alpha-latrotoxin at nerve endings. Moreover, the procedure that we report for
loading Drosophila nerve terminals with the calcium ion-sensing dye, Calcium
Crimson, may have utility for studying calcium dynamics in mutant alleles with
alterations in synapse development and function in this organism.
PMID- 9759980
TI - Quantitation of neurokinin 1 receptor internalization and recycling in guinea-pig
myenteric neurons.
AB - Agonist-induced endocytosis and recycling of G protein-coupled receptors
contributes to desensitization and resensitization of the receptors. In this
study, we have used fluorescence immunohistochemistry, confocal microscopy and
digital image analysis to quantify the proportion of receptor in the cytoplasm
and on the surfaces of nerve cells in the guinea-pig ileum. With these methods we
examined the dynamics of internalization of the neurokinin 1 receptor in response
to agonist, return of receptor to the cell membrane and its capacity to be re
internalized in response to further exposure to agonist. The basal level of
neurokinin 1 receptor immunoreactivity in the cytoplasm was 12-15% of total
cellular immunoreactivity. Concentration-response relations were generated for
neurokinin 1 receptor internalization after incubation of isolated ileum with 10(
11) to 10(-6) M substance P at 4 degrees C and warming to 37 degrees C for 20
min. The threshold concentration for cytoplasmic receptor to exceed baseline was
10(-11) M and the proportion of receptor in the cytoplasm increased with
increasing substance P concentration. The effect of two exposures to agonist was
studied using 10(-8) M and 10(-6) M substance P. After equilibration with
substance P at 4 degrees C for 1 h followed by 20 min at 37 degrees C with no
substance P, neurokinin 1 receptor immunoreactivity in the cytoplasm increased
significantly from 12% to 36+/-3% for incubation with 10(-8) M and to 64+/-3% for
10(-6) M. When return of receptor to the surface was blocked with monensin (10(
5) M), 90% of the receptor was in the cytoplasm after 1 h at 37 degrees C
following exposure to 10(-6) M substance P. After 60 min without substance P and
no monensin, receptor in the cytoplasm decreased to 19+/-2% (10(-8) M) and 38+/
4% (10(-6) M). A second period of equilibration with substance P at 4 degrees C
for 1 h followed by 20 min at 37 degrees C, without substance P, resulted in a
second wave of endocytosis; the fractions of receptor in the cytoplasm were 47+/
2% (10(-8) M) and 70 2% (10(-6) M). These results indicate that most of the
receptors on the cell surface are available for internalization and that the
receptors that return to the cell surface after endocytosis rapidly regain their
ability to bind ligand and undergo endocytosis.
PMID- 9759981
TI - Angiotensin receptor antagonism with losartan and the regression of left
ventricular hypertrophy.
PMID- 9759982
TI - Reflux nephropathy and hypertension.
AB - Renal scarring associated with vesico-ureteric reflux (VUR), most commonly
detected in young children, is associated with a significant risk of developing
hypertension in later life. Hypertension in reflux nephropathy contributes
significantly to morbidity including deterioration of renal function. The
mechanism of onset of hypertension is not clear although abnormalities of the
renin-angiotensin system and sodium/potassium ATPase activity have been described
in some cases. It is becoming clear that radiologically detectable renal scars or
small kidneys may histologically indicate a variety of diagnoses. Prediction of
the risk of developing hypertension in individual cases is difficult and
therefore regular follow-up remains the only current means of recognising these
subjects. Although prevention of renal scar development in children with VUR may
offer some benefit in reducing the incidence of hypertension, there is no uniform
action that can definitely achieve this, particularly in the very young, before
any urinary infection occurs. Primary VUR seems to be a disorder with mendelian
dominant inheritance and location of the gene may offer some hope of early
identification within certain families. Timely introduction of preventative
measures may then be possible even though reservations exist about their
effectiveness.
PMID- 9759983
TI - Effects of losartan on hypertension and left ventricular mass: a long-term study.
AB - This study evaluated the anti-hypertensive efficacy, tolerability and effects on
left ventricular mass of losartan, a selective angiotensin II receptor
antagonist, after 22 months in patients with essential hypertension. The study
included 77 hypertensive patients who were randomised at baseline to 22 months
double-blind once-daily treatment with losartan 50 mg (L group n = 44 patients,
mean age 54+/-9 years) or hydrochlorothiazide 25 mg (HCTZ group, n = 33 patients,
mean age 56+/-7 years). Routine haematology, blood chemistry, standard
electrocardiography, echocardiography and ambulatory non-invasive 24-h blood
pressure (BP) monitoring were performed at baseline and after 10 and 22 months.
The results showed good tolerability and a significant mean systolic and
diastolic BP reduction in all groups (L group: 22 mm Hg and 11 mm Hg; HCTZ group:
11 mm Hg and 7 mm Hg, respectively for systolic and diastolic mean BP). Moreover,
a remarkable reduction in left ventricular mass index was reached after 10 and 22
months only in the L group (L group: delta = -11 g/m2, P<0.02; HCTZ group: delta
= -5 g/m2, P= 0.38). In conclusion, losartan was well tolerated and produced a
significant reduction in BP and left ventricular mass in hypertensive patients
PMID- 9759984
TI - Captopril, but not nifedipine, improves endothelium-dependent vasodilation in
hypertensive patients.
AB - The present study aimed to investigate the influence of the angiotensin
converting enzyme (ACE)-inhibitor captopril and the Ca-antagonist nifedipine on
endothelium-dependent vasodilation (EDV) in the forearm of hypertensive patients.
Twenty-three middle-aged untreated hypertensive patients underwent evaluation of
EDV and endothelium-independent vasodilation (EIDV) in the forearm, by means of
local intra-arterial infusions of methacholine (MCh, evaluating EDV) and sodium
nitroprusside (SNP, evaluating EIDV), before and 1 h after intake of either
captopril (25 mg) or nifedipine (10 mg) in a randomised, double-blind fashion. A
matched normotensive control group was investigated at baseline conditions only.
Five of the hypertensives were also evaluated after 3 months of treatment with
captopril 25 mg twice daily in an open pilot study. First, the vasodilation
induced by methacholine (MCh), but not SNP, was significantly attenuated in the
hypertensive patients compared to the normotensive controls (P < 0.001 at MCh 4
microg/min). Second, although the two drugs induced a similar decline in blood
pressure (BP) 1 h after administration (-11 to 10 mm Hg/-8 to 7 mm Hg), captopril
significantly potentiated the vasodilator response to MCh (+32+/-13%, MCh 4 micr
og/min, P < 0.01) but not SNP, while nifedipine did not significantly alter the
response to either MCh or SNP. The improvement in vasodilator response to MCh
induced by captopril was closely related to the reduction in BP (r = 0.72, P <
0.01). Third, in the pilot study, 3 months of captopril treatment induced a
significant potentiation of the vasodilator response to MCh (+34+/-17%, MCh 4
microg/min, P < 0.05) in parallel with a significant BP reduction (-22+/-24/13+/
13 mm Hg, P < 0.05), while the response to SNP was unchanged. In conclusion, the
present study confirmed that essential hypertension is associated with a defect
in EDV. Furthermore, an improvement in EDV was seen in hypertensive patients
shortly after administration of captopril, but not nifedipine. In addition, a
significant beneficial effect on EDV was seen in a small pilot study during long
term treatment with captopril.
PMID- 9759985
TI - Vascular and neuroendocrine components in altered blood pressure regulation after
surgical repair of coarctation of the aorta.
AB - STUDY OBJECTIVE: To investigate potential vascular and neuroendocrine
determinants of altered blood pressure (BP) regulation in patients previously
operated on for aortic coarctation. DESIGN, SETTING AND PATIENTS: We
prospectively re-evaluated 45 patients operated on for aortic coarctation at
Strasbourg University Hospital over a 13-year period. Four of these patients were
less than 2 years old at the time of the operation and four were older than 20
years. Patient age and time since the operation were on average 21+/-13 years and
8+/-3 years, respectively. Surgery consisted of a resection with end-to-end
anastomosis for 18 patients, angioplasty (8), prosthesis (4) or sub-clavian flap
(15). RESULTS: Despite repair of the coarctation, about 40% of the patients
showed an abnormal BP status at rest. The majority of these patients had
uncomplicated borderline hypertension. The orthostasis test as well as the BP
circadian rhythm were frequently abnormal. While the ankle/arm systolic pressure
index measured at rest was generally within the normal range, diminished carotid
femoral pulse wave velocity was observed. Plasma adrenaline and aldosterone
levels were elevated in about 50% of the patients examined. CONCLUSIONS: These
new findings suggest that there are 'cause and effect' relationships between
aortic structural and functional vascular abnormalities, and augmented plasma
adrenaline and aldosterone in some patients after coarctation repair. These
phenomena are likely to be involved in altered BP regulation and might result in
recurrent hypertension.
PMID- 9759986
TI - Angiotensin-converting enzyme gene polymorphism in Nepal.
AB - It has recently been found that there were very few hypertensives in the
inhabitants of one Nepalese village, even though their salt consumption, per
capita, was as high as citizens in many western countries. To evaluate the
genetic factors involved in this phenomenon, we studied whether they had a
special genotype distribution of angiotensin-converting enzyme (ACE) gene I/D
polymorphism, which was recently reported to be involved in salt sensitivity. One
hundred and thirty-eight subjects were evaluated in Nepal. Only nine subjects
(6.5%) in this population were hypertensives (over 140/90 mm Hg) while consuming
11 g salt/day, which confirmed the previous results. The distribution of
genotypes and alleles of ACE gene I/D polymorphism was similar to that in the
Japanese and Chinese, who had five-times more hypertensives while consuming
almost as much salt as Nepalese, but significantly different from those in
Caucasians. The present study reports, for the first time, the genotype
distribution of ACE gene I/D polymorphism in Nepalese subjects. Furthermore, the
results suggest ACE gene polymorphism may not be involved in the 'salt
resistance' in this population.
PMID- 9759987
TI - The direct costs to the NHS of discontinuing and switching prescriptions for
hypertension.
AB - There is much evidence to suggest that the treatment of hypertension reduces the
risk of cardiovascular diseases and that it is cost-effective in most patients.
However, the effectiveness of treatment relies on compliance and maintenance of
treatment. Each pharmacological agent differs in terms of side effects. The
existence of side effects can result in poor compliance and switching between
treatments. A number of studies have reported high discontinuation rates for anti
hypertensive therapies. This potentially imposes costs on the health service. The
aim of this study is to use the MEDIPLUS data set to consider the cost arising
from switching and discontinuation of therapy. The analysis will assess the
resource costs in terms of extra GP visits and hospitalisations arising from
individuals switching and discontinuing treatments. The total costs of
hypertension were estimated to be around 76.5 m pound sterling per annum, of
which 26.9 m pound sterling can be attributed to patients who switch or
discontinue therapy.
PMID- 9759988
TI - Hypertension in the elderly: attitudes of British patients and general
practitioners.
AB - The perceptions of patients and GPs of the risk of stroke in treated and
untreated elderly hypertensives, and their attitudes towards anti-hypertensive
therapy were examined. To explore attitudes of patients to the management of
hypertension a qualitative approach was used, employing semi-structured
interviews, with subsequent thematic analysis of the transcriptions. A
questionnaire study of GPs' attitudes to the same subject was also conducted. The
elderly (n = 75) greatly overestimate the risks of hypertension and the benefits
of treatment. Most would accept anti-hypertensive therapy despite being informed
of the true risks, citing confidence in their doctor as the major determinant in
their decision. GPs (n = 121) were well informed of the risks and benefits, but
less than half adhere to current guidelines. GPs should be aware how much the
elderly overestimate the risks of hypertension and the benefits of its treatment.
When considering treating hypertension in this group, patient contributions in
the treatment decision-making process should be actively encouraged, especially
as many elderly hold a deferential attitude towards their doctor. Patients should
be informed of the risks of their disease and the benefits of treatment in terms
they understand. The use of visual aids helps patients to grasp the difficult
concepts of risk and benefit.
PMID- 9759989
TI - Ambulatory systolic blood pressure patterns in elderly hypertensives.
AB - In a recent study we found that patients with isolated systolic hypertension
(ISH) had two patterns of systolic blood pressure (SBP) elevations by ambulatory
BP monitoring (ABPM), sustained (S) and intermittent (I), the prognostic
significance of which seems to be different. In the present study we tried to
determine whether such patterns of SBP elevations may be detected among other
hypertensives as well. Twenty-eight elderly patients (mean age 65.5+/-5.1 years),
nine with ISH, 10 with systolodiastolic hypertension (SDH), and nine with white
coat hypertension (WCH), underwent ABPM. Average clinic BP in the ISH group was
184/83 mm Hg, in the SDH group 172/101 mm Hg, and in the WCH group 166/91 mm Hg,
where as the ABPM averages were 169/80, 167/95 and 132/73 mm Hg, respectively,
and differences held true for both daytime and night-time. Five ISH and four SDH
patients had S patterns on ABPM, while the other four ISH and six SDH patients
exhibited I patterns; none of the nine WCH subjects had either S or I patterns.
ECG revealed left ventricular hypertropy (LVH) and/or ischaemic changes in eight
patients with S patterns (ISH and SDH groups combined), as opposed to two
patients with I patterns and only one patient of the WCH group. This seems to
further suggest that an S pattern of SBP elevation on ABPM may have worse
prognostic implications than either an I pattern or no SBP elevation.
PMID- 9759990
TI - Blood pressure changes at the Dead Sea (a low altitude area).
AB - The Dead Sea (barometric pressure: 800 mm Hg) is an important balneotherapeutic
centre for chronic dermatologic and arthritic diseases. In the past, hypertensive
patients have complained sporadically of weakness and dizziness during a stay in
the Dead Sea. It was therefore recommended that hypertensives do not stay at
these health centres. The aim of our study was to investigate the changes in
blood pressure (BP) parameters of 72 hypertensive and normotensive osteoarthritic
and rheumatoid arthritic elderly patients during a 2-week stay in the Dead Sea,
and to further evaluate the effect of different balneotherapeutic means on these
BP changes. Following a primary BP assessment at the out-patient clinic (Beer
Sheva barometric pressure: 745 mm Hg), the patients were divided into four
groups: (1)thermomineral pool; (2)Dead Sea water baths; (3) combination of the
aforementioned treatments; and (4) controls (no balneotherapy). We demonstrated
that the systolic BP (SBP) of hypertensives and normotensives decreased by an
average of 17 mm Hg and that diastolic BP (DBP) decreased by an average of 8 mm
Hg from their basic clinic-measured values. These favourable results were
sustained during the first 10 days duration, and by the end of their stay they
had diminished slightly. Thermomineral water had an additional lowering effect on
the BP of the normotensives, but the SBP of hypertensives increased. Immediately
following Dead Sea bath immersion, we noted a temporary increase of SBP in
normotensives only. No patient, hypertensive or normotensive, complained of
dizziness, malaise, or any other complaint. In our experience, patients feel well
at low altitudes, and there is no justification in upholding hypertension as a
contraindication to balneotherapy in the Dead Sea.
PMID- 9759991
TI - Treatment of elderly patients with isolated systolic hypertension with isosorbide
dinitrate in an asymmetric dosing schedule.
AB - Nitrates decrease pulse pressure more than mean arterial pressure (MAP) and are
advocated for the treatment of isolated systolic hypertension (ISH). Nitrates
show drug tolerance during chronic treatment so an asymmetric dosing regimen may
prevent loss of effect of nitrates. This study investigates the anti-hypertensive
effect of isosorbide dinitrate (ISDN) given in a twice daily asymmetric dosing
regimen in elderly patients with ISH. After a 6-week placebo run-in period,
patients entered the double-blind study. Ten patients received placebo and 11
patients ISDN 20 mg b.i.d. for 8 weeks. This dose could be doubled once. Office
systolic and diastolic blood pressures (SBP/DBP) and ambulatory BP were measured.
Pulse pressure was calculated as SBP-DBP. Office pulse pressure was more reduced
during ISDN (17.9%) than with placebo (5%; P < 0.05). SBP and MAP decreased
compared to baseline, but the changes were not statistically significant between
the two groups. DBP tended to increase with ISDN compared to placebo. Mean 24-h,
mean daytime and mean night-time pulse pressure decreased after treatment with
ISDN (10.7%, 12.1%, 7.9%, respectively). Pulse pressure tended to decrease more
during the day than during the night with ISDN. No changes could be demonstrated
with placebo. In conclusion, pulse pressure decreased with ISDN, resulting in a
lower SBP without a decrease in DBP. The latter may preserve coronary perfusion
in ISH. With the asymmetric dosing regimen the decrease in pulse pressure was not
clear at night. Whether a decrease in nocturnal BP, in addition to the
spontaneous decrease, is advisable in ISH remains a matter of debate.
PMID- 9759992
TI - Valsartan and atenolol in patients with severe essential hypertension.
AB - The aim of this study was to evaluate the efficacy and tolerability of valsartan,
a new angiotensin II receptor antagonist, versus atenolol in the treatment of
severe primary hypertension. A total of 103 adult out-patients were randomised to
receive either valsartan 160 mg or atenolol 100 mg once daily for 6 weeks. If
necessary, additional blood pressure (BP) control could be provided as add-on
therapy. Both valsartan and atenolol decreased mean sitting diastolic BP (DBP)
and mean sitting systolic BP (SBP): least squares mean change from baseline in
DBP; valsartan, -20.0 mm Hg; atenolol, -20.4 mm Hg: in SBP; valsartan, -30.0 mm
Hg; atenolol, -25.5 mm Hg. There was no statistically significant difference
between the treatment groups. Add-on hydrochlorothiazide (HCTZ) 25 mg was
required by 97.2% of patients receiving atenolol and 83.6% of patients receiving
valsartan; additional verapamil SR 240 mg was also required by 58.3% of patients
receiving atenolol and 64.2% receiving valsartan. Valsartan was well tolerated,
with a comparable incidence of treatment-related adverse experiences in both
groups. In conclusion valsartan 160 mg is as well tolerated and effective as
atenolol 100 mg in lowering BP in severely hypertensive patients.
PMID- 9759993
TI - Cerebellar infarction as a complication of malignant hypertension.
PMID- 9759994
TI - Non-pharmacological treatment of hypertension: a survey of 2150 general
practitioners and internists.
PMID- 9759995
TI - Molecular alterations in bladder cancer.
AB - In recent years, significant information has been accumulated on the molecular
alterations that take place during development of transitional cell carcinoma
(TCC). A number of studies aimed at defining loss of heterozygosity have shown a
general chromosomal instability in TCC with loss of parts of chromosome 9 at
early stages of papillomas, and of chromosomes 11, 13, 3, 4, 8, 17 and 18 during
further development of the tumor. Oncogenes are activated, exemplified by
mutations in the ras gene family and overexpression of the c-erbB-2 gene, in a
minor fraction of tumors. Alterations of tumor suppressors (involved in control
of the cell cycle, DNA quality control and activation of apoptosis) seem to be
frequently involved. Among these p53 has a key role, and one p53 allele is
frequently lost in TCC followed by mutation of the remaining allele.These
alterations are correlated with survival, disease progression, invasion and
recurrence. Also frequently lost are the cell cycle control genes p16 and p15.
The predictive value of this has not yet been determined. Studies of
glycosylation genes have shown downregulation of the ABO gene, followed by loss
of ABO blood group structures and accumulation of the Lewis cell adhesion
molecules in high grade tumors. Functional proteome analysis has furthermore
identified biomarkers that are correlated with grade and stage. Molecular models
for TCC development can now be built, and clinical testing of these is urgently
needed.
PMID- 9759996
TI - Reciprocal expression of bcl-2 and p53 oncoproteins in urothelial dysplasia and
carcinoma of the urinary bladder.
AB - In order to investigate if and when the bcl-2 oncoprotein is activated in bladder
tumorigenesis and its relationship with p53 overexpression and patient survival,
we studied bcl-2 and p53 expression immunohistochemically in matched normal
urothelium, dysplasia and cancer specimens selected by step-sectioning from 54
radically resected bladders for non-metastatic transitional cell carcinoma (TCC).
In normal urothelium and mild dysplasia, bcl-2 was restricted to the basal cell
compartment, while in moderate and severe dysplasia its expression was detectable
also in the upper regions. Excess bcl-2 immunoreactivity was found in 27 (50%) of
carcinomas, and a larger proportion of high-grade TCCs showed bcl-2 expression
compared with that of low-grade TCCs (P < 0.05). Overexpression of p53 protein
showed a increasing trend toward the progression of bladder tumorigenesis (P <
0.01) and a significant reciprocal correlation was found between bcl-2 and p53
expression in either various dysplasias (P < 0.01) or carcinoma (P < 0.05). With
the evolution from mild dysplasia to carcinoma in individual cases, loss of bcl-2
expression was more frequently observed in superficial (P < 0.02) or low-grade
carcinoma (P < 0.05) than in muscle-invasive or high-grade carcinoma.
Furthermore, patients with negative immunostaining for both bcl-2 and p53 in
cancer lesions had a significantly more favorable prognosis compared with those
with positive immunostaining for the oncoproteins (P < 0.05), although bcl-2 by
itself did not predict patient survival. We suggest that aberrant activated bcl
2, which is seen earlier than p53, appears to facilitate bladder tumorigenesis
and to enhance tumor aggression in some extent.
PMID- 9759997
TI - 7-N-(2-([2-(gamma-L-glutamylamino)-ethyl]-dithio)-ethyl)-mitomycin C (KW-2149) is
more active than mitomycin C on chemonaive and drug-resistant urothelial
carcinoma cells.
AB - This in vitro study aimed to investigate the cytotoxic activity of 7-N-(2-([2
(gamma-L-glutamylamino)ethyl]dithio)ethyl)-mitomycin C (KW-2149) versus mitomycin
C (MMC) against cell lines from human transitional cell carcinoma (TCC). Direct
cytotoxicity of the two drugs was measured employing a colorimetric cytotoxicity
assay on chemonaive and chemoresistant cancer cell populations. The results
revealed that all cell lines (n = 19) were significantly more inhibited by
treatment (2 h, 96 h) with KW-2149 than by MMC (P < 0.03-0.001). pH 6.0 decreased
the stronger activity of KW-2149 (P < 0.013-0.004). Creatinine > or =10 mmol/l
and nitrosourea > or =100 mg/l also inhibited the activity of KW-2149
significantly. Tumor cells with relative drug-resistance against MMC (RT112-MMC:
55-fold) exerted minor cross-resistance to KW-2149 (fourfold). In conclusion, the
present in vitro data suggest KW-2149 to be a superior drug for intravesical
therapy of patients with primary or recurrent superficial bladder carcinoma.
Since pH and concentrations of creatinine and nitrosourea influence the activity
of KW-2149, patients are supposed to profit from neutralizing the urinary pH and
enhanced diureses.
PMID- 9759998
TI - Induction of drug-resistant bladder carcinoma cells in vitro: impact on
polychemotherapy with cisplatin, methotrexate and vinblastine (CMV).
AB - Residual tumor, tumor progression or relapse after chemotherapy of patients with
advanced or metastasized transitional cell carcinoma of the bladder (TCCB) are
suggested to reflect intrinsic drug resistance of cancer cells, or the
development of chemotherapy-resistant tumor cell populations. The present study
aimed to establish drug-resistant subculture cell lines from human TCCB, selected
for anticancer drugs, administered in the cisplatin, methotrexate and vinblastine
(CMV) polychemotherapy protocol. Tumor cells from chemonaive cell lines of human
TCCB (HT1376, TCCSUP) have been exposed to progressively increasing
concentrations of cis-diamminedichloroplatinum (II) (CDDP), methotrexate (MTX),
vinblastine (VBL) or etoposide (VP16). The resulting drug-resistant subculture
cell lines (HT1376-CDDP, HT1376-MTX, HT1376-VBL, HT1376-VP, TCCSUP-CDDP, TCCSUP
MTX, TCCSUP-VBL, TCCSUP-VP) were analyzed with regard to the achieved resistance
factor (RF) for the inductive anticancer agent, the acquisition of cross
resistance, DNA content, cell cycle distribution and cellular morphology.
Parental HT1376 cells were intrinsically less sensitive to all anticancer drugs
(1.7-50x), compared with TCCSUP cells. Relative resistance against the inductive
anticancer agents was similar for the final drug-resistant subculture cell lines
of both parental cell lines concerning CDDP and VP-16 (RF: 4-5x), but were
reciprocal for MTX and VBL, respectively. MTX led to much stronger resistance (RF
> 200) than the other drugs (RF < 10). Pleiotropic cross-resistances were
observed in six out of eight (75%) drug-resistant subculture cell lines. Highest
RF (50-500x) and frequency of cross-resistance (five of six cell lines) occured
for MTX, and the least from exposure to CDDP (one of six cell lines). Overall,
the results corroborated the central role of CDDP against urothelial carcinoma
whereas repetitive applications of MTX appeared to be a doubtful strategy.
Moreover, the experiments provide the largest panel so far of drug-resistant cell
lines of human TCCB. They represent an appropriate tool for basic research on
drug-resistance mechanisms, for the development and screening of future
anticancer drugs or to elaborate strategies to overcome drug resistance for those
patients who ultimately fail to respond to standard chemotherapy.
PMID- 9760000
TI - Cactus flower extracts may prove beneficial in benign prostatic hyperplasia due
to inhibition of 5alpha reductase activity, aromatase activity and lipid
peroxidation.
AB - The cactus flower is deemed to be helpful in benign prostatic hyperplasia (BPH)
therapy, although there is no published information regarding its clinical effect
in patients and on the mechanism of its biological activity. The present study
evaluated the ability of cactus flower extracts to exert an effect on BPH through
possible inhibition of such processes as lipid peroxidation, androgen
aromatization and testosterone reduction. Cactus flower extracts indeed inhibited
aromatase and 5alpha reductase activity in cultured foreskin fibroblasts, and
also in human placental and prostatic homogenates. The inhibitory activity in
both instances was associated with the dichloromethane or ethanol (methanol)
extracts, while a marked antioxidative activity was associated with the aqueous
extract. The finding that cactus flower extracts interfere concurrently in vitro
with aromatase and reductase activity as well as with free radical processes
suggests that these substances may prove beneficial in BPH treatment.
PMID- 9759999
TI - Expression of gonadotropin-releasing hormone (GnRH) and GnRH receptor mRNA in
prostate cancer cells and effect of GnRH on the proliferation of prostate cancer
cells.
AB - The purpose of this study was to determine the production of gonadotropin
releasing hormone (GnRH), the co-occurrence of GnRH receptors in prostate cancer
cells, and the effect of GnRH on prostate cancer cell proliferation. Four human
prostate cancer cell lines were studied. LNCaP is an androgen sensitive prostate
cancer cell line, DU-145 and PC-3 are androgen resistant, and TSU-Pr1 is
uncharacterized. The expression of GnRH and GnRH receptor mRNAs were assessed by
in situ hybridization and the effect of exogenous GnRH on proliferation of
prostate cancer cells was measured by thymidine incorporation assay. GnRH mRNA
expression, determined by in situ hybridization, was found in 83.48% of the
LNCaP, 89.7% of the TSU-Pr1, 86.2% of the PC-3 and 95.3% of the DU-145. Signals
of GnRH receptor mRNA were detected in more than 95% of the cells of all four
cell lines. The proliferation of the prostate cancer cells grown in media
supplemented with peptide hormone lacking charcoal-stripped serum was
significantly (P < 0.05) suppressed. No significant effect of GnRH on the
proliferation of all four prostate cancer cells was observed. In summary,
prostate cancer cells produced GnRH and its receptors, and exogenous GnRH
treatment did not affect the prostate cancer cell proliferation. The existence of
GnRH and GnRH receptor mRNA in the same cell suggests that the role of GnRH
produced by prostate cancer cells would be autocrine.
PMID- 9760001
TI - Quantitative analysis on the localization of chondroitin sulfate proteoglycan in
renal tissues of patients with calcium nephrolithiasis.
AB - Previous studies have shown a significant decrease of heparin sulfate
proteoglycan (HSPG) in the basement membrane of the glomerulus and the mucosa of
the ureter/renal pelvis in patients with calcium nephrolithiasis. In this study,
we looked at the localization of another influential proteoglycan, chondroitin
sulfate (CSPG), using similar study groups by indirect immunofluorescence
staining. Microscopic images were digitized and image analysis was used to
quantitate the staining intensity of CSPG present in the basement membrane of the
nephron. Our data showed significant loss of CSPG in the Bowman's capsule and the
basement membrane of the mucosa of the ureter/renal pelvis using Mann-Whitney U
Wilcoxon Rank Sum W test with P-values of 0.0043 and 0.0041, respectively.
However, absence of staining was noted in the basement membrane of the glomerulus
and no significant change in the basement membrane of the tubular epithelium was
observed. In conclusion, our results showed changes in the localization of CSPG
in the basement membrane of the nephron, accompanied with HSPG, which may
contribute to the pathological condition of calcium nephrolithiasis.
PMID- 9760002
TI - The effect of urease inhibitors on the encrustation of urethral catheters.
AB - Encrustation and blockage of indwelling urethral catheters is primarily brought
about by infection of the urinary tract by Proteus mirabilis or other urease
producing species. The bacteria colonise the catheter forming a biofilm community
within a polysaccharide matrix. The activity of the urease drives up the urinary
pH and causes the crystallisation of calcium and magnesium phosphates in the
biofilm. We have used a simple physical model of the catheterised bladder to
investigate the ability of urease inhibitors to control encrustation. It was
observed that acetohydroxamic acid (1.0 mg/ml) and fluorofamide (1.0 microg/ml)
restricted the increase in pH of P. mirabilis-infected urine from 9.1 to 7.6.
Significant reductions in the deposition of calcium and magnesium salts were also
recorded on the silicone catheters. Electron microscopy confirmed that
encrustation and occlusion of the catheter lumen was minimal in the presence of
the urease inhibitors. The data from this in vitro study suggests that urease
inhibitors, particularly fluorofamide, could have clinical applications in the
prevention of catheter encrustation and blockage.
PMID- 9760003
TI - Guiding spontaneous tissue regeneration for urethral reconstruction: long-term
studies in the rabbit.
AB - We designed long-term in vivo experiments to study rabbit urethral regeneration
and remodelling over a hyaluronan biodegradable prosthesis. Seven months after
the resection of a 1.5-cm-long tract of the urethra and its substitution with the
prosthesis, radiological analysis showed the disappearance of the implant and the
re-establishment of urethral continuity along the transmural defect. The
regenerated tissue remodelled around the implant and exhibited good
distensibility under pressure. Histological evaluation showed that the neo
urethra was lined with transitional epithelium and the stroma contained abundant
elastic fibres. An examination of the pattern of the major cytoskeletal and
cytocontractile proteins of smooth muscle cells and fibroblasts was able to
distinguish fibroblasts from smooth muscle cells and myofibroblasts in the neo
urethra. These experiments provide evidence for the potential, successful use of
biocompatible/bioresorbable devices for reconstructive surgery of the urethra.
PMID- 9760004
TI - Elevated tubular proteinuria, albuminuria and decreased urinary N-acetyl-beta-D
glucosaminidase activity following unilateral total ureteral obstruction in rats.
AB - Urinary tubular proteinuria and N-acetyl-beta-D-glucosaminidase (NAG) activity
has not yet been studied after unilateral total ureteral obstruction (UTO). The
aim of the study was (1) to evaluate in a longitudinal study (7 weeks) the
behaviour and the potential clinical value of tubular proteinuria and urinary NAG
activity after UTO; (2) to study the physiopathology of the non-obstructed
contralateral kidney by using these two different markers of tubular damage.
METHODS: in 28 female, adult Wistar rats (UTO: n = 16, sham: n = 12), tubular
proteinuria and urinary NAG activity were measured before and 1 and 5 weeks after
surgery. RESULTS: a significant (P < 0.01) increase in tubular
proteinuria/creatinine ratio and urinary creatinine and a decrease in urinary NAG
activity was found 1 week after UTO. All parameters normalized after 6 weeks.
Albuminuria increased progressively (P < 0.01) during the study. CONCLUSION:
tubular proteinuria increases during the first week following UTO in rats. The
initial increase of low molecular weight proteins following UTO is not due to
tubular damage as no parallel increase of urinary NAG was found. We suggest an
initial tubular overperfusion with primary urine, due to an increased single
nephron glomerular filtration and overruling the reabsorption capacity of the
proximal tubules.
PMID- 9760005
TI - CYP2E1 genotyping in renal cell/urothelial cancer patients in comparison with
control populations.
AB - OBJECTIVE: Genetic polymorphisms in enzymes involved in carcinogen metabolism
have been found to influence susceptibility to cancer. Ethanol-inducible CYP2E1
is an enzyme of major toxicological interest because it metabolizes several
drugs, precarcinogens, and solvents to reactive metabolites. In the present
investigation, we studied the cytochrome P450 2E1 genetic polymorphism in renal
cell/urothelial cancer patients in comparison with healthy control populations in
the regions of Jena and Halle in Germany. PATIENTS AND MATERIAL: DNA of
peripheral white blood cells was isolated both from 273 renal cell/urothelial
cancer patients and 298 controls from the regions of Jena and Halle. METHOD: We
focused on polymorphisms in the promoter region and intron 6 of the CYP2E1 gene.
The polymorphims were identified as restriction fragment length polymorphisms
(RFLPs) by polymerase chain reaction (PCR) and subsequently applying the
restriction enzymes PstI/RsaI and DraI. RESULTS: In the region of Jena as well as
of Halle, the frequency distributions of the PstI/RsaI, DraI, and combined DraI +
PstI/RsaI genotypes showed no significant differences between controls and renal
cell/urothelial cancer patients. We did not find significant differences between
Jena and Halle. 86.7% of all subjects with a homozygote PstI/RsaI genotype also
carried a homozygote DraI genotype, whereas 5.2% of all subjects with a
heterozygote PstI/RsaI genotype also carried a heterozygote DraI genotype. The
heterozygote genotype of PstI/RsaI polymorphism always determines the
heterozygote genotype of DraI polymorphism. Our results failed to demonstrate any
differences in the distribution of CYP2E1 polymorphisms between renal
cell/urothelial cancer patients and controls. CONCLUSION: Summing up, our results
show that CYP2E1 genotype cannot predict risk for renal cell/urothelial cancer in
the population from 2 different regions in Germany. The results demonstrate a
lack of association between CYP2E1 genetic polymorphism and renal cell
cancer/urothelial cancer.
PMID- 9760006
TI - Long-term therapy with policosanol improves treadmill exercise-ECG testing
performance of coronary heart disease patients.
AB - This study examined the effects of long-term lipid-lowering therapy with
policosanol on the clinical evolution, and exercise-ECG testing responses of 45
coronary heart disease (CHD) patients with myocardial ischemia, documented by
exercise 201T1-myocardial perfusion scintigraphy, in an overall randomized,
double-blind, placebo-controlled trial, made for different test endpoints.
Fifteen patients were treated with 5 mg of policosanol twice daily; another 15
patients were administered the same drug dose plus 125 mg aspirin; and the other
15 patients received placebo plus equal aspirin dose. They were followed for 20
months, previous baseline observations, with treadmill exercise-ECG, besides
serum lipid test. Beneficial changes on proportions among the 2 policosanol
groups and the placebo group, showed an increment on functional capacity class, a
decrement on rest and exercise angina, and a significant decrease in cardiac
events, and in ischemic ST segment response, especially in the policosanol plus
aspirin group (p = 0.05, X2(2df) = 5.8; p = 0.04, p = 0.02; Fisher). After
treatment, sets of mean changes revealed an increase on maximum oxygen uptake,
and a decline on double product simultaneously in both policosanol groups (p < or
= 0.02, p < or = 0.002; Pillais, Hotellings' T2), while the placebo group was
impaired. Aerobic functional capacity percent showed an increment in policosanol
groups (p < or = 0.05, paired T). Lipid levels improved as other endpoints
already reported. A supposed ergogenic effect of octacosanol, policosanol's main
active compound, was not detected with this design. These results show that
policosanol-treated CHD patients improved clinical evolution, and exercise-ECG
responses, owing to the amelioration of myocardial ischemia, even more when
administered with aspirin.
PMID- 9760007
TI - Endosulfan poisoning in Northern India: a report of 18 cases.
AB - Eighteen cases of endosulfan poisoning by accidental overexposure during spray,
admitted between October 1995 to September 1997, were observed and analyzed.
These accounted for approximately one third of the total number of poisoning
cases admitted in our unit during this period. Nausea, vomiting abdominal
discomfort, tonic and clonic convulsions, confusion, disorientation, and muscular
twitchings were cardinal manifestations. None of the patients succumbed to their
illness. Analysis of various incriminating factors revealed that accidental
overexposure was due to failure to adhere to the instructions for spray either
due to ignorance or due to illiteracy. All the patients avoided preventive
measures and developed toxicity both due to inhalation and absorption through
skin. Endosulfan (a chlordiene derivative) poisoning is gaining up momentum in
this part of world and has become an important matter for public health in India.
PMID- 9760008
TI - Drug-induced admissions to medical wards at Jordan University Hospital.
AB - The objective of this study was to determine the prevalence of drug-induced
disease necessitating hospital admission to Jordan University Hospital. This
study also attempted to identify the most commonly involved drugs as well as the
vulnerable groups of patients and the potential causes which favor the problem.
All admissions to Internal Medicine Department were screened for drug-induced
causality by detailed drug history and appropriate examination. The prevalence
rate of drug-induced admissions was 3.6%, 52% of them were females. Many of the
cases were of severe nature. Most of the cases were due to predictable effects of
the drugs used, which were mainly chemotherapeutic agents. The bone marrow was
the most affected body organ. Results are in agreement with reports published
elsewhere and can be explained by the fact that Jordan University Hospital is the
main teaching hospital in Jordan, has an intermediate location and is a referral
hospital for oncology-hematology service.
PMID- 9760009
TI - Influence of captopril, propranolol, and verapamil on arterial pulse wave
velocity and other cardiovascular parameters in healthy volunteers.
AB - OBJECTIVE: The effects of antihypertensive agents on cardiovascular parameters,
especially on arterial pulse wave velocity, remain largely unknown in
normotensive subjects. Therefore, the present investigation was designed to
evaluate acute effects of ACE inhibitor captopril,beta-adrenoceptor blocker
propranolol and calcium entry blocker verapamil on cardiovascular and ventilatory
function in healthy volunteers. MATERIAL: The influence of single doses of
captopril (25 mg), propranolol (40 mg), and verapamil (80 mg) on cardiovascular
function and exercise capacity were compared in healthy volunteers in a
randomized, double-blind, placebo-controlled fashion. METHODS: Cardiac output and
beat-by-beat blood pressure were estimated non-invasively before and after the
drug administrations by whole-body impedance cardiography and Finapres finger
blood pressure monitoring, respectively. Arterial pulse wave velocity was
obtained from the time delay between flow pulses measured from the root of the
aorta and the popliteal artery, and systemic vascular resistance was calculated
from cardiac output and mean arterial pressure. In addition, a progressive
maximal exercise test was performed after the treatments. RESULTS: Propranolol
reduced heart rate, cardiac output and arterial pulse wave velocity, and
increased systemic vascular resistance clearly more effectively than placebo. In
addition, captopril effectively decreased arterial resistance and pulse wave
velocity. However, the influence of verapamil on cardiovascular parameters did
not significantly differ from those observed in placebo-treated subjects.
Exercise peak heart rate, peak blood pressure, and minute ventilation were
reduced in subjects treated with propranolol, but not in those treated with
captopril and verapamil, when compared to placebo. CONCLUSIONS: Acute
administration of captopril and propranolol but not verapamil clearly modulated
cardiovascular parameters in rest, suggesting differential effects of these
compounds on cardiovascular function in healthy volunteers. These drugs seem to
have disparate effects on arterial pulse wave propagation as an indicator of
arterial compliance after short-term administration in healthy subjects.
Captopril and verapamil had no effect on cardiovascular and ventilatory function
during maximal exercise, while propranolol markedly altered also these variables
in the present study.
PMID- 9760010
TI - Pharmacokinetics of lubeluzole (Prosynap) after single intravenous doses in
healthy subjects.
AB - The single-dose pharmacokinetics of lubeluzole were investigated in 2 single
blind, placebo-controlled, dose-escalation studies in healthy male subjects. In
the first study, 6 subjects received an intravenous infusion of 2.5, 5, and 10 mg
lubeluzole. In the second study, a 15 mg dose of lubeluzole was administered to 6
subjects, of whom 5 also received 20 mg and 2 also 25 mg lubeluzole. Following
the infusion, plasma lubeluzole concentrations decayed biphasically, with a mean
distribution half-life (t1/2alpha) of 30 to 65 minutes and a mean terminal half
life (t1/2beta) of 15 to 24 hours. The results of the 2 studies indicate that
lubeluzole exhibits linear kinetics over the dose range tested in healthy male
subjects.
PMID- 9760011
TI - The duration of antidiuretic response of two desmopressin nasal sprays.
AB - The duration of antidiuretic response and pharmacokinetics of desmopressin were
investigated in 16 healthy, male overhydrated volunteers after intranasal
administration of 20 microg desmopressin (dDAVP). The antidiuretic activity was
determined by measuring urine osmolality and diuresis over a period of 24 hours.
Both study preparations were equally effective regarding a rapid onset of
activity and a highly reproducible extent of effect. Urine osmolalities, analyzed
as areas under the time curve (AUCosm) were similar for both nasal sprays. Urine
volumes were comparable. Bioequivalence was assessed for the primary criterion
AUCosm by a calculated mean ratio (test/reference) of 100.9% (90% confidence
interval ranging from 88.0% to 115.6%). Plasma levels of desmopressin, measured
by a specific and sensitive radioimmunoassay method, were already detectable 20
minutes after administration. The mean time courses showed a similar shape with
increased concentration levels for the test preparation. Consequently maximum
desmopressin plasma concentrations were different, showing high interindividual
variability. However, the times of reaching maximum plasma concentrations were
similar. AUC(0-24h) was significantly raised after treatment with the test
preparation (mean ratio of 127.9%; 90% confidence interval ranging from 106.6% to
153.5%). A subanalysis of the 2 reference batches with the two-sided t-test
procedure for parallel groups resulted in a mean ratio of 83.1% with a 90%
confidence interval ranging from 67.2% to 102.7%. The estimated ratios of the 2
batches of the reference preparation were borderline to the equivalence range. In
conclusion, both study preparations had the same pronounced biological effect
with different desmopressin bioavailabilities.
PMID- 9760012
TI - Effect of fat distribution on the pharmacokinetics of cortisol in obesity.
AB - OBJECTIVE: Patients with predominantly upper body obesity are at greater risk for
developing diabetes mellitus, hyperlipidemia, hypertension, and cardiovascular
disease. Little is known about the mechanisms involved in the regulation of
regional body distribution. It has been accepted that the accumulation of fat
into adipose tissue depends on regional metabolic regulation of adipocytes and
that glucocorticoids play a role in this mechanism. The aim of the present study
is to investigate how the pharmacokinetics of cortisol correlate to
intraabdominal and subcutaneous fat distribution in obese patients. METHODS: A
group of 24 obese patients (13 males and 11 females) were submitted to a CT scan
for intraabdominal and subcutaneous fat area evaluation. A 30-min cortisol
infusion (0.25 mg/kg) was administered and plasma cortisol was measured over 6
hours. RESULTS: Patients with larger intraabdominal fat areas were found to have
a higher cortisol clearance than those with lower intraabdominal fat areas.
Cortisol clearance (both, absolute and body-weight corrected) showed a
statistically significant correlation with intraabdominal fat area, either
expressed by waist-hip ratio or obtained by computerized tomography. CONCLUSIONS:
These findings indicate a more effective clearance capability for cortisol in
patients with central obesity resulting in lowered cortisol plasma levels despite
an increased cortisol secretion observed in this patient group.
PMID- 9760013
TI - Plasma coenzyme Q10 concentrations in breast cancer: prognosis and therapeutic
consequences.
AB - BACKGROUND: Coenzyme Q10 or ubiquinone is a redox component of the respiratory
chain, which may be involved in the pathogenesis of cancer. METHODS: In order to
better understand the role of this vitamin in the pathogenesis of breast cancer,
a clinical trial including 200 women hospitalized for the biopsy and/or the
ablation of a breast tumor was conducted. Ubiquinone plasma concentrations were
determined simultaneously with vitamin E plasma concentrations (as antioxidant
reference) by HPLC. RESULTS: A coenzyme Q10 deficiency was noted both in
carcinomas (80 patients) and non-malignant lesions (120 patients), while vitamin
E concentrations were within the normal range. A correlation was shown between
the intensity of the deficiency and the bad prognosis of the breast disease based
on high TNM and SBR values or the lack of estrogen receptors. However, neither
cathepsin D level nor adenopathy invasion was related to ubiquinone levels.
CONCLUSIONS: Since prooxidants may promote tumorigenesis, ubiquinone
supplementation in breast cancer could be relevant.
PMID- 9760016
TI - Seminal androgen concentrations and residual sperm cytoplasm.
AB - To explore a possible link between seminal androgen concentrations and residual
sperm cytoplasm, which constitutes one of the cytological anomalies of the
spermatozoon middle piece, testosterone (T), delta4-androstenedione, the
precursor of T during testicular androgen biosynthesis and the active metabolite
of T, dihydrotestosterone, were assayed in the seminal fluid of 37 patients. A
statistically significant correlation was found by linear regression (r = +0.380,
P = 0.020, y = 0.02x + 0.45) between seminal T concentrations and the percentage
of spermatozoa with a residual cytoplasmic droplet. Given the impact on fertility
of residual sperm cytoplasm, assessment of seminal T concentrations could provide
useful information on the fertility status of patients.
PMID- 9760015
TI - Antioxidant status in hyperphenylalaninemia.
AB - Abnormal oxidative stress was observed in some inborn errors of metabolism owing
to the accumulation of toxic metabolites leading to excessive free radical
production and to the influence of restricted diets on the antioxidant status.
Erythrocyte antioxidant enzymes activities and tocopherol concentrations were
measured in a group of phenylketonuric (n = 42) and mild-hyperphenylalaninemic (n
= 28) patients compared with 45 age-matched controls. We also determined plasma
selenium levels in these groups. We also evaluated the possible relationship
between antioxidant status and neuropsychological disorders. Erythrocyte
glutathione peroxidase (GSH-Px) activity was significantly lower (P < 0.001) in
both phenylketonuric and mild-hyperphenylalaninemic patients compared with the
control group, but no differences were observed between the two groups of
patients. Neuropsychological disturbances were more frequent in the group of PKU
patients with low GSH-Px activity than in PKU patients with normal GSH-Px. Low
GSH-Px activity might be explained in phenylketonuria as a result of a selenium
deficiency caused by a poor selenium intake or absorption, but not in mild
hyperphenylalaninemic patients with free diet. Selenium levels were normal in
both groups of patients, so low glutathione peroxidase activity in both
phenylketonuric and hyperphenylalaninemic groups might be influenced by other
factors, such as the consequences of an unbalanced amino acid profile, common to
both conditions.
PMID- 9760014
TI - Clinical efficacy and safety of beclomethasone dipropionate inhalation capsules
inhaled by Cyclohaler compared with Becotide Rotacaps inhaled by Rotahaler.
AB - The study was undertaken to compare the efficacy and safety of beclomethasone
dipropionate inhalation powder inhaled by Rotahaler (Becotide Rotacaps, Glaxo
Wellcome) and by Cyclohaler (Beclomethasone Cyclocaps, Pharmachemie). Both the
Cyclohaler and the Rotahaler are single-dose dry powder inhalation devices for
inhalation capsules. 182 asthma patients stabilized on inhaled beclomethasone
dipropionate 800 micrograms daily, were randomly assigned to treatment with 800
micrograms beclomethasone dipropionate inhaled by Rotahaler (91 patients) or
Cyclohaler (91 patients) in a double-blind manner, using the double-dummy method.
It was shown that the asthma remained stable during the 16-week study period with
both preparations. There were no statistically significant differences in the
pulmonary parameters (morning PEF, evening PEF, FEV1). The test/reference ratio
of the morning PEF (99.5%, CI 93.0% - 106.5%) was well within the equivalence
interval, which had been set a priori from 85% to 117.6%. There were no marked
differences between the Cyclocaps and Rotacaps group in symptom scores and
adverse events. A total of 12 patients had an asthma exacerbation: 8
exacerbations occurred in the Rotahaler group and 4 in the Cyclohaler group. The
difference was not statistically significant. The use of rescue medication was
somewhat higher in the Rotahaler group, but the difference did not reach
statistical significance. Significantly more patients (17 patients) withdrew from
the study in the Rotahaler group than in the Cyclohaler group (5 patients). In
conclusion, there was no difference in asthma control of patients treated with
Beclomethasone Cyclocaps inhaled by Cyclohaler and Becotide Rotacaps inhaled by
Rotahaler. Both preparations are therapeutically equivalent.
PMID- 9760017
TI - Determination of serum tetranectin: technical and clinical evaluation of three
sandwich immunoassays.
AB - The performance of two sandwich-type immunoassays for the determination of the
tumour marker tetranectin using monoclonal antibodies Hyb 130-13 and 130-14 as
catching layer was compared with the performance of a polyclonal assay.
Sensitivities were 0.4-0.6 microg/l, and intra- and inter-assay coefficients of
variation were < 10% in all assays. One-hundred-and-ten blood donors were
examined, and women had higher concentrations of tetranectin in serum than men
when measured with monoclonal assays (P < 0.05). In preoperative serum samples
from 43 patients with ovarian cancer, tetranectin concentrations were reduced (P
< 0.001), and the mean tetranectin concentration decreased with increasing FIGO
stage of the patients (P < 0.05). In sera from patients with ovarian cancer,
tetranectin concentrations were lower in the polyclonal assay than in the
monoclonal assays. This could, hypothetically, be explained by ligand-binding or
other conformational changes in tetranectin, influencing the antigenicity of the
molecule.
PMID- 9760018
TI - Production and certification of an enzyme reference material for creatine kinase
isoenzyme 2 (CRM 608).
AB - We describe the preparation of a lyophilized material containing purified human
creatine kinase 2 (CK-MB), and the certification of its catalytic concentration.
The material can be used to verify the comparability of results from different
laboratories, for intra-laboratory quality control, or for calibration of the
creatine kinase 2 catalytic concentration measurements. The enzyme was purified
from human heart by ethanol precipitation and chromatography successively on DEAE
Sephacel and Blue-Sepharose. The purified enzyme had a specific activity of 998.4
U/mg and was > 99% pure on polyacrylamide gel electrophoresis. The material was
examined for several possible contaminating enzymes, which were found to be
absent. The purified creatine kinase 2 had two subunits (B and M) with molecular
masses of 43,650 and 41,700 g/mol, respectively, and an isoelectric point at pH
5.8. The material was prepared by diluting the purified creatine kinase 2 in a
matrix containing 25 mmol/L PIPES buffer, pH 7.2, 2 mmol/L ADP, 5 mmol/L 2
mercaptoethanol, 154 mmol/L sodium chloride and 50 g/L human serum albumin,
dispensing it into vials and freeze-drying. The batch was shown to be
homogeneous. The loss of enzyme activity on storage at -20 degrees C is predicted
to be less than 0.18% per annum on the basis of accelerated degradation studies.
The catalytic concentration of creatine kinase in samples of the reconstituted
material is certified to be 67.2+/-1.8 U/L (1.12+/-0.03 microkat/L) when
measured, at 30 degrees C, by the Recommended Method of the International
Federation of Clinical Chemistry.
PMID- 9760019
TI - Expression and processing of recombinant human galactosylceramidase.
AB - Stable transformants of CHO cells that overexpress human galactosylceramidase
(GALC) were established. The GALC within the cell consisted of 50- and 30-kDa
proteins. The active GALC secreted into the culture medium in large amounts
consisted of the 80-kDa precursor enzyme. We confirmed that the precursor enzyme
was taken up by fibroblasts via the mannose-6-phosphate receptor and processed
into the 50- and 30-kDa fragments. Fragmentation was inhibited by the
lysosomotropic agents chloroquine and NH4Cl, suggesting that it occurs within the
lysosome. GALC mutations identified in globoid cell leukodystrophy suppressed
fragmentation. Neither the 50- or 30-kDa fragment expressed had GALC activity,
indicative that the entire structure is necessary for enzyme activity and that
fragments expressed separately cannot associate to form the active enzyme.
PMID- 9760020
TI - Noninvasive monitoring using serum amyloid A and serum neopterin in cardiac
transplantation.
AB - The monitoring of allograft function for cardiac transplant patients still relies
on endomyocardial routine biopsies. We investigated the diagnostic value of
noninvasive monitoring using the parameters serum amyloid A protein and serum
neopterin. The circulating levels of the acute phase reactant, amyloid A protein,
and the macrophage product, neopterin, were measured serially in 13 patients
after cardiac transplantation. The mean period of observation was 240 days. Nine
acute cardiac allograft rejections, five cases of viral infection and eight cases
of bacterial infection occurred. The levels of serum amyloid A protein and serum
neopterin remained low (x = 6.0 mg/dL and 12.6 nmol/L, respectively) during the
periods of stable graft function. In contrast, both parameters were significantly
elevated (p < 0.01) during the rejection episodes (x = 12.7 mg/dL and 38.0 nmol/L
for serum amyloid A protein and serum neopterin, respectively). For a reliable
differentiation between rejection and stable graft function, serum amyloid A
protein had a diagnostic accuracy of 84% (with a cut-off level of 10 mg/dL) and
serum neopterin had one of 75% (with a cut-off level of 23 nmol/L). However,
significant increases in the circulating levels of serum amyloid A protein and
serum neopterin were also observed during bacterial (x = 14.9 and 88 nmol/L,
respectively) and viral (x = 6.2 mg/dL and 44 nmol/L, respectively) infections.
The detection of immunological complications after cardiac transplantation using
serial measurements of serum amyloid A protein and serum neopterin is possible.
These parameters can be used to help in judging both the need and the optimal
timing for the otherwise frequent endomyocardial biopsies.
PMID- 9760021
TI - The stability of retinol, alpha-tocopherol, trans-lycopene, and trans-beta
carotene in liquid-frozen and lyophilized serum.
AB - The concentrations of retinol, alpha-tocopherol, and trans-beta-carotene in
lyophilized serum stored at -25 degrees C and -80 degrees C have been monitored
for 10 years. There was no evidence of degradation of any of these compounds over
the 10-year period. Retinol, alpha-tocopherol, and trans-beta-carotene were less
stable at -25 degrees C in liquid-frozen serum than they were in lyophilized
serum. At -80 degrees C, trans-beta-carotene levels were stable for up to 3 years
of storage in liquid-frozen serum. Both retinol and alpha-tocopherol appeared
stable in liquid-frozen serum for at least 5 years at -80 degrees C. The effect
of repeated freeze/thaw cycles on retinol, alpha-tocopherol, trans-lycopene, and
trans-beta-carotene in liquid-frozen and reconstituted lyophilized serum both
stored at -20 degrees C was also studied. Retinol, alpha-tocopherol, trans
lycopene, and trans-beta-carotene in reconstituted lyophilized serum stored at
20 degrees C were stable for at least 3 days with minimal (< 5) freeze/thaw
cycles.
PMID- 9760022
TI - Simultaneous measurement of catecholamines and kallikrein in urine using boric
acid preservative.
AB - Catecholamines, dopamine and the renal kallikrein-kinin system may participate in
the pathogenesis of hypertension. In the past these systems have been studied
independently in isolation. Attempts to study the systems together have been
hampered by incompatibility of the current urine preservatives for the two assays
involved. In order to measure acid-stable catecholamines and acid-labile
kallikrein enzyme together, we have established boric acid solution as a
preservative by comparing the stability of urinary catecholamines stored in it
with the commonly employed preservative, hydrochloric acid (HCl) as well as the
stability of urinary kallikrein in untreated urine with and without boric acid at
ambient temperatures for 24 and 48 h, and at -20 degrees C for 2 weeks and 1, 2
and 3 months. The stability of other common urine parameters including cortisol,
electrolytes, creatinine and protein, was also investigated after storage with
boric acid at ambient temperature for 24 h. Our results showed that there was a
good agreement between the measurements of urinary catecholamines stored in both
HCl and boric acid and that the latter did not interfere with measurements of
urinary kallikrein or other common urine parameters.
PMID- 9760023
TI - Comparison of indices for serum vitamin E status in healthy subjects.
PMID- 9760024
TI - Evaluation of cannabimimetic effects of structural analogs of anandamide in rats.
AB - Arachidonylethanolamide (anandamide), an endogenous ligand for the cannabinoid
receptor, binds competitively to brain cannabinoid receptors and shares many, but
not all, of the in vivo effects of delta9-tetrahydrocannabinol. In this study,
the cannabinoid effects of anandamide analogs in which the anandamide molecule
was altered were assessed in a drug discrimination model. Structural
manipulations of the anandamide molecule included saturation of the arachidonyl
moiety with fluorination (O-586), substitution for either the ethanolamide moiety
(O-612 and O-595) or C2' hydroxyl (O-585), and addition of a methyl group at
various positions (O-610, O-680, and O-689). Despite the low binding affinities
of the non-methylated compounds (Ki values > 2000 nM), all of the analogs had
previously shown cannabinoid activity in mice. In the present study, these
analogs were tested in a more pharmacologically specific delta9
tetrahydrocannabinol discrimination procedure in rats. This animal model is
predictive of the subjective effects of marijuana intoxication in humans. Whereas
delta9-tetrahydrocannabinol and an aminoakylindole fully substituted for the
training dose of 3 mg/kg delta9-tetrahydrocannabinol, anandamide and its non
methylated analogs were not cannabimimetic in this procedure. Methylation
appeared to increase binding affinity (Ki values < 150 nM) and efficacy; however,
the greatest substitution produced by the methylated analogs occurred only at
doses that decreased overall rates of responding, suggesting that these analogs
are not fully delta9-tetrahydrocannabinol-like. The rapid metabolism of
anandamide and some of its analogs undoubtedly contribute to the differences
between the pharmacological profiles of the anandamides and classical
cannabinoids. These results support the prediction that the subjective effects of
anandamide analogs that have been developed thus far would not be cannabimimetic
except at high doses.
PMID- 9760025
TI - Cannabinoids decrease acetylcholine release in the medial-prefrontal cortex and
hippocampus, reversal by SR 141716A.
AB - The effect of delta9-tetrahydrocannabinol, the psychoactive principle of
marijuana, and [R-(+)-(2,3-dihydro-5-methyl-3-[[4-morpholinylmethyl]pyrol[1,2,3-d
e-]-1,4-benzoxazin-6y)(1-naphthalenyl)methanone monomethanesulfonate] (WIN 55,212
2), a synthetic cannabinoid receptor agonist, on the acetylcholine output in the
medial-prefrontal cortex and hippocampus was studied by microdialysis in freely
moving rats. The administration of delta9-tetrahydrocannabinol (1 and 5 mg/kg
i.p.) and WIN 55,212-2 (5 and 10 mg/kg i.p.) produced a long lasting inhibition
of acetylcholine release in both areas. The inhibitory effect of delta9
tetrahydrocannabinol and WIN 55,212-2 was suppressed in both areas by the
specific cannabinoid CB1 receptor antagonist, [N-(piperidin-1-yl)-5-(4
chlorophenyl)-1-(2,4-dichlorophenyl)-4-me thyl-1H-pyrazole-3carboxamide]HCl (SR
141716A), at the dose of 0.1 mg/kg i.p., per se ineffective to modify basal
acetylcholine release. Most interestingly, SR 141716A alone at higher doses
increased acetylcholine release both in the medial-prefrontal cortex (3 mg/kg
i.p.) and hippocampus (1 and 3 mg/kg i.p.), suggesting that acetylcholine output
is tonically inhibited by endogenous cannabinoids. Since the inhibitory effect of
delta9-tetrahydrocannabinol is produced by doses within those relevant to human
use of marijuana, our results suggest that the negative effects of the latter on
cognitive processes may be explained by its ability to reduce acetylcholine
release in the medial-prefrontal cortex and hippocampus. Conversely, cannabinoid
receptor antagonists may offer potential treatments for cognitive deficits.
PMID- 9760026
TI - Effect of losartan on afferent nerve stimulation.
AB - The present study was undertaken to investigate the effects of losartan, a non
peptide angiotensin II subtype 1 (AT1) receptor antagonist, on both the pressor
responses elicited by stimulation of afferent vagal nociceptive fibres and the
involvement of the sympathetic nervous system (evaluated by plasma levels of
noradrenaline and its co-neurotransmitter neuropeptide Y) in dogs. Electrical
stimulation of the afferent fibres of the vagus (1, 5, 10 and 20 Hz) elicited a
frequency-dependent increase in blood pressure and heart rate. Plasma
noradrenaline levels only increased after stimulation at frequencies of 10 and 20
Hz. Plasma neuropeptide Y levels did not change. Losartan (10 mg/kg i.v.) induced
both a decrease in resting blood pressure and an increase in basal plasma levels
of noradrenaline and neuropeptide Y. Losartan failed to modify the magnitude of
the electrically-evoked pressor and positive chronotropic responses. The
angiotensin AT1 receptor antagonist elicited a fall in plasma noradrenaline
values after a 1 Hz stimulation and abolished the increase in plasma
noradrenaline levels induced by the 10 (but not 20) Hz stimulation. The data
suggest that angiotensin AT1 receptors are not directly involved in acute pressor
responses induced by stimulation of afferent vagal fibres. Moreover, the results
show that, besides its sympatho-inhibitory effect, losartan can exert a sympatho
excitatory action as shown by the increase in the plasma levels of both
noradrenaline and its coneurotransmitter, neuropeptide Y.
PMID- 9760027
TI - Acetylsalicylic acid potentiates the antinociceptive effect of morphine in the
rat: involvement of the central serotonergic system.
AB - Acetylsalicylic acid and morphine are the most widely distributed and most
frequently used drugs in the relief of pain, but their analgesic activity has
adverse side-effects. Mixtures containing these two drugs are frequently used to
relieve mild to moderate pain despite the paucity of relevant experimental
evidence so far published. We set out to study the possible antinociceptive
effect of a combination of subactive doses of the two drugs in rats. A
combination of low doses of acetylsalicylic acid (50 mg/kg i.p.) and morphine (3
mg/kg s.c.) was administered and the pain threshold was evaluated in the hot
plate and formalin tests, and 5-HT2 receptor binding capacity, 5
hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels were
measured in the cortex and pontine areas of the brain. The combination of
acetylsalicylic acid and morphine had an analgesic effect in both tests that was
associated with an increase in 5-HT levels and a decrease in 5-HT2 receptors in
the cortex. These effects were either completely abolished or partially prevented
by i.p. pretreatment with naloxone (1 mg/kg i.p.). Our results demonstrate that
subactive doses of acetylsalicylic acid and morphine can exert analgesic and
biochemical effects when given in combination in the rat and suggest an
involvement of serotonergic and opiatergic systems.
PMID- 9760028
TI - Opposing roles for dopamine D1 and D2 receptors in the regulation of hypothalamic
tuberoinfundibular dopamine neurons.
AB - The purpose of the present study was to characterize pharmacologically dopamine
D1 receptor-mediated inhibition of tuberoinfundibular dopamine neurons in males
rats, and to determine if inhibitory dopamine D1 receptors oppose stimulatory
dopamine D2 receptors and account for the inability of mixed dopamine receptor
agonists to alter the activity of these neurons. Tuberoinfundibular dopamine
neuronal activity was estimated by measuring the concentrations of the dopamine
metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the median eminence, the
region of the hypothalamus containing terminals of these neurons. Administration
of the dopamine D1 receptor agonist (+/-)-1 phenyl-2,3,4,5-tetrahydro-(1 H)-3
benzazepine-7,8-diol (SKF38393) decreased median eminence DOPAC and increased
plasma prolactin concentrations, whereas administration of the dopamine D1
receptor antagonist ((-)-trans,6,7,7a,8,9,13b-hexahydro-3-chloro-2-hydroxy-N
methyl-5H -benzo[d]naphtho-[2,1 b]azepine (SCH39166) increased median eminence
DOPAC concentrations but had not effect on plasma prolactin. The inhibitory
effect of SKF38393 on median eminence DOPAC concentrations was blocked by
SCH39166. These results demonstrate that acute activation of dopamine D1
receptors inhibits the activity of tuberoinfundibular dopamine neurons and
thereby increases prolactin secretion, and that under basal conditions dopamine
D1 receptor-mediated inhibition of tuberoinfundibular dopamine neurons is
tonically active. Administration of the dopamine D2 receptor agonist (5aR-trans)
5,5a,6,7,8,9,9a,10-octahydro-6-propyl-pyridol[2, 3-g]quinazolin-2-amine
(quinelorane) increased median eminence DOPAC concentrations, and SKF38393 caused
a dose-dependent reversal of this effect. Administration of the mixed dopamine
D1/D2 receptor agonist R(-)-10,11-dihydroxy-apomorphine (apomorphine) had no
effect per se, but blocked quinelorane-induced increases in DOPAC concentrations
in the median eminence. These results reveal that concurrent activation of
dopamine D1 and D2 receptors nullifies the actions of each of these receptors on
tuberoinfundibular dopamine neurons, which likely accounts for the lack of an
acute effect of mixed dopamine D1/D2 receptor agonists on these hypothalamic
dopamine neurons.
PMID- 9760029
TI - The difference in the inhibitory mechanisms of papaverine on vascular and
intestinal smooth muscles.
AB - Papaverine (0.3-100 microM) more potently inhibited phenylephrine (1 microM)
induced contraction than 65 mM K+-induced contraction of the aorta, while it
equally inhibited contractions induced by 65 mM K+ and carbachol (1 microM) in
ileal smooth muscle. In phenylephrine-treated aorta, papaverine (1-10 microM)
increased the cAMP and cGMP content. However, in carbachol-treated ileum, 30
microM papaverine partially increased the cAMP content while it maximally relaxed
the preparation. In fura2-loaded aorta, papaverine (0.3-10 microM) inhibited both
the contraction and the increase in intracellular Ca2+ level ([Ca2+]i) induced by
phenylephrine in parallel. However, papaverine inhibited carbachol-induced
contraction with only a small decrease in [Ca2+]i. Papaverine (1-30 microM)
inhibited the carbachol-induced increase in oxidized flavoproteins, an indicator
of increased mitochondrial oxidative phosphorylation, in ileal smooth muscle
whereas it did not change the phenylephrine-induced increase in the aorta. These
results suggest that papaverine inhibits smooth muscle contraction mainly by the
accumulation of cAMP and/or cGMP due to the inhibition of phosphodiesterase in
the aorta whereas, in ileal smooth muscle, papaverine inhibits smooth muscle
contraction mainly by the inhibition of mitochondrial respiration.
PMID- 9760030
TI - Effects of the optical isomers of verapamil on electrophysiological properties of
the heart in conscious dogs.
AB - We compared the cumulative dose-response relations of verapamil (0.1, 0.2 and 0.4
mg kg(-1)) in different R/S enantiomer ratios (100/0, 90/10, 80/20, 50/50 and
20/80) on the electrophysiological and hemodynamic characteristics of the heart
using the conscious dogs. A reduction of mean arterial pressure occurred with
20R/80S producing a 3-times greater decrease than 100R/0S, but an increase in
heart rate occurred with 20R/80S producing a 9-times greater increase than
100R/0S. Increased heart rate was concurrent with decreased mean arterial
pressure most prevalent with a higher ratio of S-isomer that produced a greater
reduction in mean arterial pressure and increase in heart rate at lower overall
verapamil doses. Atrio-ventricular conduction time increased 3-5 min after each
infusion, with 20R/80S producing a 4-times greater effect than 100R/0S. These
results indicate that the peripheral and cardiac electrophysiologic properties of
various nonracemic verapamil mixtures are mainly attributable to the
concentration of S-isomer.
PMID- 9760031
TI - Impaired endothelium-dependent relaxation in large, but not small arteries in
rats after coronary ligation.
AB - Vascular responses were studied in both large and small arteries of rats
following 8 weeks of heart failure produced by coronary ligation. Responses to
noradrenaline, acetylcholine and sodium nitroprusside were studied in isolated
thoracic aorta and mesenteric arteries. In the aorta, concentration-response
curves for noradrenaline were similar between heart failure and sham animals and
unaffected by the nitric oxide synthase inhibitor, NG-nitro-L-arginine (L-NOARG).
Relaxation by acetylcholine was impaired in heart failure rats (EC50-6.79 log M
heart failure vs. -7.15 log M sham). In the presence of L-NOARG, relaxation by
acetylcholine was completely abolished in rings from sham rats, whereas
constriction was observed in rings from heart failure rats. Relaxation by sodium
nitroprusside was not different between sham and heart failure rats. In
mesenteric arteries, responses to noradrenaline, acetylcholine and sodium
nitroprusside were not different between heart failure and sham rats. L-NOARG
reduced the maximum response to acetylcholine in both heart failure (82% to 50%)
and shams (89% to 49%) by a similar magnitude, with no effect on relaxation to
sodium nitroprusside. These data suggest that acetylcholine-induced relaxation is
impaired in the aorta, but not mesenteric arteries in rats with heart failure.
The mechanism is not solely due to impaired nitric oxide release and may be due
to acetylcholine-induced contraction.
PMID- 9760032
TI - Evidence for different 5-HT1B/1D receptors mediating vasoconstriction of equine
digital arteries and veins.
AB - 5-hydroxytryptamine (5-HT) is a potent vasoconstrictor of equine digital arteries
and veins which may play a role in the ischaemic disease, laminitis. The present
investigation compared the properties of 5-HT1B/1D receptors in arteries with
those in veins using isolated rings of equine digital blood vessels. The 5
HT1B/1D receptor-selective agonists, anpirtoline and sumatriptan were 17.9 and 10
times more potent and produced 4.1 and 5.6 times greater maximum contractions,
respectively, in veins when compared to arteries. Other agonists tested were of
equal potency and produced the same maximum responses in veins and arteries.
Propranolol competitively inhibited 5-HT1B/1D receptor mediated responses in
arteries, with a pKB of 6.7, but had no significant effects on responses in veins
at 1 microM. Metergoline competitively inhibited 5-HT1B/1D receptor mediated
responses in veins, with a pKB of 8.1, but had no significant effect in arteries
at 0.1 microM. These data suggest that 5-HT1B/1D receptors mediating
vasoconstriction in equine digital arteries are pharmacologically different to
those found in digital veins.
PMID- 9760034
TI - A comparison of the effects of capsaicin with inhibitory nerve stimulation in the
rat anococcygeus muscle in vitro.
AB - Capsaicin was used to test whether centrifugal activation of sensory fibres in
the rat anococcygeus muscle can contribute to non-adrenergic non-cholinergic
(NANC) relaxation of the muscle. In a solution containing 0.5 mM Ca2+ and in the
presence of carbachol (10 microM) capsaicin evoked a fast concentration-dependent
relaxation of the muscle that was usually followed by a smaller, slower, relaxant
response. The fast relaxant response was reduced when extracellular Ca2+ was
raised to 2.5 mM, desensitized after a single application of capsaicin and was
blocked by tetrodotoxin (1 microM) or ruthenium red (10 microM). The fast
response was greatly reduced by haemoglobin, by cold storage of the muscles or by
N-monomethyl-L-arginine (100 microM) in the absence but not in the presence of L
arginine (100 microM). It is concluded that centrifugal activation of sensory
fibres evokes a nitric oxide-mediated relaxation of the anococcygeus muscles that
probably contributes to electrically evoked NANC relaxation.
PMID- 9760033
TI - Blockade of beta-adrenoceptors enhances cAMP signal transduction in vivo.
AB - The aim of this study was to determine whether the blockade of beta-adrenoceptors
would enhance cAMP-mediated signal transduction processes in vivo. The
administration of the membrane permeable cAMP analogue, 8-(4-chlorophenylthiol)
cAMP (8-CPT-cAMP, 10 micromol/kg, i.v.) produced an increase in heart rate (+27
+/- 2%, P < 0.05), a fall in mean arterial blood pressure (-21 +/- 3%, P < 0.05)
and falls in hindquarter (-12 +/- 3%, P < 0.05) and mesenteric (-32 +/- 3%, P <
0.05) vascular resistances in pentobarbital-anesthetized rats. The beta
adrenoceptor antagonist, propranolol (1 mg/kg, i.v.) lowered heart rate (-12 +/-
3%, P < 0.05) but did not affect mean arterial blood pressure or vascular
resistances. The tachycardia, hypotension and vasodilation produced by 8-CPT-cAMP
were exaggerated after administration of propranolol (P < 0.05 for all
comparisons). The nitric oxide-donor, sodium nitroprusside (2 microg/kg, i.v.),
produced falls in mean arterial blood pressure and vascular resistances of
similar magnitude to those produced by 8-CPT-cAMP. These sodium nitroprusside
induced responses were unaffected by propranolol (P < 0.05 for all comparisons).
Sodium nitroprusside also produced a minor increase in heart rate (+5 +/- 1%, P <
0.05) which was abolished by propranolol. These findings suggest that 8-CPT-cAMP
directly increases heart rate and that blockade of beta-adrenoceptors enhances
the potency of cAMP within the heart and vasculature.
PMID- 9760035
TI - Oxytocin receptor binding and uterotonic activity of carbetocin and its
metabolites following enzymatic degradation.
AB - Metabolites of the analogue 1-deamino-1-carba-2-tyrosine(O-methyl)-oxytocin
(carbetocin) following incubation with a rat kidney homogenate were isolated and
their pharmacodynamic properties investigated. Apart from the parent compound two
metabolites were identified namely desGlyNH2-carbetocin (carbetocin metabolite I)
and desLeuGlyNH2-carbetocin (carbetocin metabolite II). Both carbetocin,
carbetocin metabolite I and carbetocin metabolite II displayed binding affinities
to the myometrial oxytocin receptor of a similar magnitude as oxytocin.
Carbetocin was found to have agonistic properties on isolated myometrial strips
and it was found to exert this effect through generation of inositol phosphates,
as is the case for oxytocin. However, maximal contractile effect of carbetocin
was approximately 50% lower than that of oxytocin (2.70 +/- 0.12 g compared to
5.22 +/- 0.26 g) and EC50 was approximately ten times higher (48.0 +/- 8.20 nM
compared to 5.62 +/- 1.22 nM). Neither carbetocin metabolite I nor carbetocin
metabolite II were able to contract isolated myometrial tissue. All three
compounds displayed antagonistic properties against oxytocin in vitro, with
carbetocin being the strongest inhibitor (pA2 = 8.21) and carbetocin metabolite
II (pA2 = 8.01) being stronger than carbetocin metabolite I (pA2 = 7.81). These
results indicate that carbetocin is a partial agonist/antagonist to the oxytocin
receptor while the two metabolites carbetocin metabolite I and carbetocin
metabolite II are pure antagonists. All three analogues bound to the myometrial
vasopressin V1 receptor, albeit with much lower affinities than to the oxytocin
receptor. Carbetocin metabolite II showed the weakest binding affinity of 33.7 +/
7.34 nM compared to 7.24 +/- 0.29 nM for carbetocin and 9.89 + 2.80 nM for
carbetocin metabolite I. Only carbetocin bound to the renal vasopressin V2
receptor though the binding affinity was very low (61.3 +/- 14.6 nM).
PMID- 9760036
TI - Differential effects of inhibitors of cyclooxygenase (cyclooxygenase 1 and
cyclooxygenase 2) in acute inflammation.
AB - The anti-inflammatory activity of drugs more selective for cyclooxgenase isoform
inhibition (cyclooxygenase 1, cyclooxygenase 2), were compared in rat carrageenin
induced pleurisy. Suppression of inflammation by cyclooxygenase 2-selective
inhibitors, NS-398 (N-[-2-cyclohexyloxy]-4-nitrophenyl methanesulphonamide) and
nimesulide (4-nitro-2-phenoxy-methanesulfonanilide), and by piroxicam and
aspirin, more selective for cyclooxygenase 1, was measured. Piroxicam and aspirin
significantly inhibited inflammatory cell influx, exudate and prostaglandin E2
formation, 6 h after carrageenin injection. Cyclooxygenase 2 inhibitors had
little effect on these parameters with NS-398 alone reducing prostaglandin E2
levels, but increasing levels of leukotriene B4. In contrast, at 3 h after
carrageenin injection, cyclooxygenase 2 inhibitors significantly inhibited all
inflammatory parameters however suppression with piroxicam and aspirin was
greater, and more pronounced than at 6 h. NS-398 and nimesulide dosing did not
reduce thromboxane B2 production from platelets isolated from rats with
carrageenin-induced pleurisy, demonstrating that at the doses used,
cyclooxygenase 2 inhibitors did not inhibit cyclooxygenase 1, as platelets
contain only this isoform. Therefore, in the rat carrageenin-induced pleurisy,
drugs more selective for the inhibition of cyclooxygenase 1 attenuate
inflammation over a wider time frame than cyclooxygenase 2-selective drugs,
suggesting a significant role for cyclooxygenase 1 in this model. Inhibition of
cyclooxygenase 2 by NS-398 however, resulted in an increase in the potent
chemoattractant leukotriene B4.
PMID- 9760037
TI - Bradykinin-evoked Ca2+ mobilization in Madin Darby canine kidney cells.
AB - We studied the mechanisms underlying the bradykinin-evoked changes in
intracellular calcium concentration ([Ca2+]i) in Madin Darby canine kidney (MDCK)
cells. Bradykinin evoked a [Ca2+]i transient in a dose-dependent manner, measured
by fura-2 fluorimetry and digital video imaging. The transient consisted of a
rise and a decay and [Ca2+]i returned to baseline without oscillations. External
Ca2+ influx occurred, as demonstrated by Mn2+ quench and external Ca2+ removal
measurements. Bradykinin acted by stimulating bradykinin B2 receptors as
evidenced by blockade by D-arginyl-L-arginlyl-L-prolyl-trans-4-hydroxy-L
prolylglycyl -3-(2-thienyl)-L-alanyl-L-seryl-D-1,2,3,4-tetrahydro-3
isoquinolineca rbonyl-L-(2alpha,3beta,7alphabeta)-octahydro-1 H-indole-2-carbonyl
L-arginine (HOE 140) but not by D-arginyl-L-arginlyl-L-prolyl-trans-4-hydroxy-L
proylglycyl- 3-(2-thienyl)-L-alanyl-L-seryl-D-1,2,3,4-tetrahydro-3
isoquinolinecar bonyl-L-(2alpha,3beta,7alphabeta)-octahydro-1 H-indole-2-carbonyl
([Des-Arg]HOE 140). The [Ca2+]i signal was abolished by 1-(6-((17beta-3
methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1 H-pyrrole-2,5-dione (U73122)
and partially inhibited by neomycin, implying mediation by phospholipase C. The
transient was initiated by a release of Ca2+ from internal stores since it was
abolished by pretreatment with thapsigargin or cyclopiazonic acid. The
mobilization of the internal Ca2+ store subsequently triggered a 1-[beta-[3-(4
methoxyphenyl)propoxy]-4-methoxyphenethyl]-1 H-imidazole hydrochloride (SKF
96365)-insensitive Ca2+ entry. Pretreatment with carbonylcyanide m
chlorophynylhydrozone and gly-phe-beta-naphthylamide did not alter the transient,
thus excluding the participation of mitochondria and lysosomes. Efflux via Ca2+
pumps contributed to the decay of the transient. Efflux via Na+/Ca2+ exchange or
sequestration by mitochondria and lysosomes was insignificant. The transient was
blunted by the protein kinase C activator phorbol 12-myristate 13-acetate, and
was enhanced by the protein kinase C inhibitors sphingosine and chelerythrine,
the protein kinase A inhibitor 2,5-di-(t-butyl)-1,4-hydroquinone, N-[2-(p
bromocinnamylamino)ethyl]5-isoquinolinesulfonamide (H-89), the agent 8
(diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), and agents that elevated
levels of 3',5'-cyclic guanosine monophosphate. The transient did not
heterologously desensitize with that evoked by ATP, ADP or UTP.
PMID- 9760038
TI - Tenidap enhances P2Z/P2X7 receptor signalling in macrophages.
AB - Tenidap is an anti-inflammatory drug whose mechanism of action is not fully
understood. It has been shown to block plasma membrane anion transport and to
decrease release of interleukin-1beta, probably via the inhibition of interleukin
1beta converting enzyme. In the present study we showed that: (a) tenidap
increases the sensitivity of mouse macrophages to cytotoxic effects mediated by
extracellular ATP; (b) tenidap increases lucifer yellow uptake through the
macrophage ATP receptor; (c) pretreatment with oxidised ATP, a blocker of the
P2Z/P2X7 receptor, inhibits cytotoxicity and lucifer yellow uptake due to the
combined effects of ATP and tenidap; (d) macrophages lacking the P2Z/P2X7
receptor are resistant to the synergistic effect of tenidap and ATP. The results
suggest that tenidap synergises with extracellular ATP for activation of the
P2Z/P2X7 receptor.
PMID- 9760039
TI - Agonist and antagonist actions of antipsychotic agents at 5-HT1A receptors: a
[35S]GTPgammaS binding study.
AB - Recombinant human (h) 5-HT1A receptor-mediated G-protein activation was
characterised in membranes of transfected Chinese hamster ovary (CHO) cells by
use of guanosine-5'-O-(3-[35S]thio)-triphosphate ([35S]GTPgammaS binding). The
potency and efficacy of 21 5-HT receptor agonists and antagonists was determined.
The agonists, 5-CT (carboxamidotryptamine) and flesinoxan displayed high affinity
(subnanomolar Ki values) and high efficacy (Emax > 90%, relative to 5-HT = 100%).
In contrast, ipsapirone, zalospirone and buspirone displayed partial agonist
activity. EC50s for agonist stimulation of [35S]GTPgammaS binding correlated well
with Ki values from competition binding (r = +0.99). Among the compounds tested
for antagonist activity, methiothepin and (+)butaclamol exhibited 'inverse
agonist' behaviour, inhibiting basal [35S]GTPgammaS binding. The actions of 17
antipsychotic agents were investigated. Clozapine and several putatively
'atypical' antipsychotic agents, including ziprasidone, quetiapine and
tiospirone, exhibited partial agonist activity and marked affinity at h5-HT1A
receptors, similar to their affinity at hD2 dopamine receptors. In contrast,
risperidone and sertindole displayed low affinity at h5-HT1A receptors and
behaved as 'neutral' antagonists, inhibiting 5-HT-stimulated [35S]GTPgammaS
binding. Likewise the 'typical' neuroleptics, haloperidol, pimozide, raclopride
and chlorpromazine exhibited relatively low affinity and 'neutral' antagonist
activity at h5-HT1A receptors with Ki values which correlated with their
respective Kb values. The present data show that (i) [35S]GTPgammaS binding is an
effective method to evaluate the efficacy and potency of agonists and antagonists
at recombinant human 5-HT1A receptors. (ii) Like clozapine, several putatively
'atypical' antipsychotic drugs display balanced serotonin h5-HT1A/dopamine hD2
receptor affinity and partial agonist activity at h5-HT1A receptors. (iii)
Several 'typical' and some putatively 'atypical' antipsychotic agents displayed
antagonist properties at h5-HT1A sites with generally much lower affinity than at
hD2 dopamine receptors. It is suggested that agonist activity at 5-HT1A receptors
may be of utility for certain antipsychotic agents.
PMID- 9760040
TI - Omega-3 polyunsaturated fatty acids--modulation of voltage-dependent L-type Ca2+
current in guinea-pig tracheal smooth muscle cells.
AB - Omega-3 polyunsaturated fatty acids have been reported to be associated with
favorable changes in the respiratory system. To determine one of the mechanisms
for this effect, membrane currents were recorded in guinea-pig tracheal myocytes
by using the whole-cell voltage clamp technique. Without EGTA in the patch
pipette containing the Cs-internal solution, command voltage pulses positive to
+0 mV from a holding potential of -60 mV elicited a voltage-dependent L-type Ca2+
current (I(Ca x L)) and a subsequent outward current. Upon repolarization, slowly
decaying inward tail currents were recorded. The outward currents and the inward
tail current were enhanced by methyl-1,4,-dihydro-2,6-dimethyl-3-nitro-4-(2
trigluromethylphenyl )-pyridine-5-carboxylate, and blocked by Cd2+ or nifedipine.
Inclusion of EGTA (5 mM) in the patch pipette also abolished these currents,
indicating that they were Ca2+-dependent. When [Cl-]o or [Cl-]i was changed, the
reversal potential of these currents shifted, thus behaving like a Cl(-)
sensitive ion channel. 4,4'-Diisothiocyanatostilbene-2,2'-disulphonic acid. a Cl-
channel blocker, inhibited the currents. The omega-3 polyunsaturated fatty acids
eicosapentaenoic acid (3-30 microM) and docosahexaenoic acid (30 microM)
suppressed I(Ca x L) and then inhibited I(Ca x Cl) in a reversible manner.
Similar inhibitory effects of eicosapentaenoic acid on I(Ca x L) were observed
with 5 mM EGTA in the patch pipette. Neurokinin A (1 microM) and caffeine (10 mM)
also transiently activated I(Cl x Ca), probably due to Ca2+ release from Ca2+
storage sites. Pretreatment of the cells with eicosapentaenoic acid markedly
suppressed the activation of I(Cl x Ca) by neurokinin A or caffeine. These
results suggest that omega-3 polyunsaturated fatty acids inhibit voltage
dependent L-type Ca2+ currents and also Ca2+-activated Cl- currents in tracheal
smooth muscle cells from the guinea-pig, which may play a role in modulation of
tracheal smooth muscle tone.
PMID- 9760041
TI - Antagonist binding profile of the split chimeric muscarinic m2-trunc/m3-tail
receptor.
AB - Recent evidence suggests that G-protein-coupled receptors can behave as multiple
subunit receptors, and can be split into parts, maintaining their binding
ability. Transfection of a truncated muscarinic m2 receptor (containing
transmembrane domains I-V, named m2-trunc) with a gene fragment coding for the
carboxyl-terminal receptor portion of the muscarinic m3 receptor (containing
transmembrane domains VI and VII, named m3-tail) results in the formation of a
binding site with a high affinity for the muscarinic ligand N
[3H]methylscopolamine. In this paper we analyse the antagonist binding profile of
this chimeric m2-trunc/m3-tail receptor in comparison with the wild-type
muscarinic m2 and m3 receptors. While many of the substances tested had an
intermediate affinity for the chimeric m2-trunc/m3-tail receptor compared with m2
and m3, some compounds were able to distinguish between the chimeric m2-trunc/m3
tail receptor on the one hand and the m2 or the m3 receptor on the other. Among
them, tripitramine (a high-affinity M2 receptor antagonist) bound to the m2
trunc/m3-tail receptor with the same affinity as m2, but it bound to the m3
receptor with a 103-fold lower affinity; pirenzepine (a selective muscarinic M1
receptor antagonist) bound to the chimeric receptor with an affinity that was 12-
and 3-fold higher than that of m2 and m3, respectively. The results of this study
demonstrate that the chimeric m2-trunc/m3-tail receptor has a pharmacological
profile distinct from that of the originating muscarinic m2 and m3 receptors.
PMID- 9760042
TI - Subtype-specific stimulation of [35S]GTPgammaS binding by recombinant alpha2
adrenoceptors.
AB - We measured agonist-stimulated binding of the stable GTP-analog guanosine-5'-O-(3
[35S]thiotriphosphate) ([35S]GTPgammaS) as a functional assay to monitor G
protein activation by recombinant human alpha2-adrenoceptor subtypes alpha2A,
alpha2B and alpha2C. (-)-Noradrenaline was a full agonist in all receptors.
Dexmedetomidine, UK14,304, clonidine and oxymetazoline showed subtype-selectivity
in efficacy. Dexmedetomidine was a full agonist at alpha2B and a partial agonist
at alpha2A; UK14,304 was a full agonist at alpha2A and a partial agonist at
alpha2B. Clonidine and oxymetazoline were weak partial agonists at the alpha2B
subtype, but appeared inactive at alpha2A and alpha2C. The [35S]GTPgammaS binding
assay provides functional information on pertussis toxin-sensitive G-protein
activation, complementing radioligand binding assays and conventional second
messenger assays.
PMID- 9760043
TI - Nitric oxide modulates sympathetic control of left ventricular contraction in
vivo in the dog.
AB - Recently, evidence has been presented that nitric oxide (NO) modulates myocardial
contraction induced by beta-adrenergic stimulation in vitro and in vivo. In this
study, we investigated whether inhibition of the L-arginine NO system augments
the positive inotropic response of the left ventricle to direct stimulation of
the sympathetic nerves in vivo in the dog. Electrical stimulation was applied to
the left stellate ganglion (LSG) for 1 min at submaximal (5 V, 2.5, 5 and 10 Hz)
and supramaximal intensities (10 V, 10 Hz) in twelve anesthetized and vagotomized
dogs. Next, in the same dogs, N(omega)-nitro L-arginine methylester (L-NAME) was
infused into the left anterior descending (LAD) coronary artery, and LSG
stimulation repeated using the same protocol. Finally, L-arginine was infused
into the LAD artery, and LSG stimulation repeated. We used the maximum of the
first derivative of left ventricular pressure (LV max d P/dt) as an index of the
myocardial contractility. Plasma epinephrine and norepinephrine concentrations
were measured in the coronary sinus at 5 V, 2.5 Hz before and after L-NAME
treatment in five of twelve dogs. L-NAME treatment significantly augmented the
inotropic response of the left ventricle (percent change in the LV max dP/dt) to
LSG submaximal stimulation trains from 164 +/- 13 to.212 +/- 21 (P < 0.03), from
187 +/- 15 to 234 +/- 25 (P < 0.05) and from 220 +/- 19 to 280 +/- 33% (P <
0.05), respectively. This response was reversed by L-arginine treatment. However,
the inotropic response to the supramaximal stimulation train did not change after
L-NAME and L-arginine treatment. L-NAME significantly increased plasma
norepinephrine concentration from 0.69 +/- 0.41 to 1.00 +/- 0.52 ng/ml without
changing plasma epinephrine concentration in the coronary sinus. It is concluded
that the inhibition of the L-arginine NO system augmented the positive inotropic
effect on the left ventricle during sympathetic nerve stimulation in normal dogs
in vivo.
PMID- 9760044
TI - Cholinesterases in cardiac ganglia and modulation of canine intrinsic cardiac
neuronal activity.
AB - Cholinergic neurotransmission plays a significant role in intrinsic cardiac
ganglia with the action of acetylcholine being terminated by acetylcholinesterase
(AChE, EC 3.1.1.7). Anatomical studies were performed to characterize neurons
associated with AChE and a closely related enzyme, butyrylcholinesterase (BuChE,
EC 3.1.1.8), in canine intrinsic cardiac ganglia. Histochemical staining for AChE
and BuChE in canine right atrial neurons showed that there were four neuronal
populations, namely, those that contained AChE only, BuChE only, both AChE and
BuChE, and those that did not contain either enzymes. The neuronal activity of
intrinsic cardiac neurons in response to substrates and inhibitors of
cholinesterases were studied in anesthetized dogs. The activity of intrinsic
cardiac neurons, as measured by changes in the number of action potentials,
increased by local application of acetylcholine. However, local application of
butyrylcholine led to a considerably greater increase in the activity of
intrinsic cardiac neurons. In keeping with the neurochemical heterogeneity in
intrinsic cardiac ganglia with respect to cholinesterases, the activity generated
by most butyrylcholine-sensitive neurons was not influenced by acetylcholine and
the activity generated by the most acetylcholine-sensitive neurons was not
influenced by butyrylcholine. This suggests that these two agents preferentially
influence different populations of intrinsic cardiac neurons. Enzyme kinetic
studies demonstrated that canine AChE preferentially catalyzed the hydrolysis of
acetylcholine while canine BuChE preferentially catalyzed the hydrolysis of
butyrylcholine. Cholinesterase inhibitors Ro 2-1250 and Ro 2-0638 inhibited both
canine cholinesterases, while huperzine A preferentially inhibited canine AChE
and ethopropazine inhibited canine BuChE. The activity of neurons in the
intrinsic cardiac ganglia significantly increased when Ro 2-1250 or Ro 2-0638 was
administered locally. The activity of neurons was not affected when huperzine A
or ethopropazine was administered, indicating that both cholinesterases must be
inhibited to increase neuronal activity. In summary, these data show that in
addition to AChE, intrinsic cardiac ganglia also contain distinct populations of
neurons that are associated with BuChE, and the activity generated by these
neurons is differentially influenced by their substrates. Because simultaneous
inhibition of AChE and BuChE leads to increased neuronal activity, it is
concluded that AChE- and BuChE-positive intrinsic cardiac neurons may act
synergistically to influence the overall tonic activity of intrinsic cardiac
ganglia.
PMID- 9760045
TI - Antagonist precipitated clonidine withdrawal in rat: effects on locus coeruleus
neurons, sympathetic nerves and cardiovascular parameters.
AB - The goal of the present study was to examine the effect of clonidine withdrawal
on the neural control of blood pressure. Rats were treated for 7-13 days with
clonidine via osmotic minipumps (200 microg kg(-1) day(-1), s.c.). Controls
received saline or were sham operated. Withdrawal was precipitated by the alpha2
adrenergic receptor (alpha2-AR) antagonist atipamezole. Most experiments were
done under halothane anesthesia. Chronic treatment with clonidine did not change
mean arterial pressure (MAP) or heart rate (HR) but raised femoral artery
resistance and the activity of locus coeruleus neurons slightly. Atipamezole
given to rats treated chronically with clonidine produced the following effects:
no change in MAP, severe tachycardia, sustained increase in splanchnic
sympathetic nerve discharge (SND; +75 +/- 13%), transient increase in lumbar SND
(+23 +/- 7%), ON-OFF activity pattern in the locus coeruleus (LC). The ON phase
of LC activity was synchronized with upswings of SND and with small changes in
MAP. A second alpha2-AR antagonist, methoxyidazoxan, produced effects identical
to those of atipamezole. Atipamezole given to control rats produced no effect on
MAP, HR, SND or LC activity. Atipamezole reversed the hypotension,
sympathoinhibition and bradycardia produced by acute administration of clonidine.
In awake rats treated chronically with clonidine, atipamezole did not change MAP
but produced arterial pressure lability and tachycardia. In conclusion, under
anesthesia, selective alpha2-AR antagonists elicit a clonidine withdrawal
syndrome that displays autonomic characteristics reminiscent of the spontaneous
withdrawal syndrome found in awake rats. The most prominent features of this
syndrome are tachycardia, sympathoactivation, lack of hypertension and an
oscillating activity pattern of brainstem neurons leading to abrupt changes in
SND and in MAP.
PMID- 9760046
TI - GABA- and glutamate-immunoreactive synapses on sympathetic preganglionic neurons
projecting to the superior cervical ganglion.
AB - Our previous work suggests that virtually all of the synapses on sympathetic
preganglionic neurons projecting to the rat adrenal medulla are immunoreactive
for either the inhibitory amino acid, gamma-aminobutyric acid (GABA) or the
excitatory amino acid, L-glutamate. To investigate whether or not this is true
for other groups of sympathetic preganglionic neurons, and to determine whether
or not the proportion of inputs containing each type of amino acid
neurotransmitter is the same for different groups of sympathetic preganglionic
neurons, we retrogradely labelled rat and rabbit sympathetic preganglionic
neurons projecting to the superior cervical ganglion and used post-embedding
immunogold on ultrathin sections to localise GABA- and glutamate
immunoreactivity. The cell bodies and dendrites of both rat and rabbit
sympathetic preganglionic neurons projecting to the superior cervical ganglion
received synapses and direct contacts from nerve fibres immunoreactive for GABA
and from nerve fibres immunoreactive for glutamate. In the rat, GABA was present
in 48.9% of the inputs to sympathetic preganglionic neurons projecting to the
superior cervical ganglion, and glutamate was present in 51.7% of inputs. Double
immunogold labelling for glutamate and GABA on the same section, as well as
labelling of consecutive serial sections for the two antigens, indicated that
GABA and glutamate occur in separate populations of nerve fibres that provide
input to rat sympathetic preganglionic neurons projecting to the superior
cervical ganglion. We now have shown that GABA or glutamate is present in
virtually all of the inputs to sympathetic preganglionic neurons projecting to
the superior cervical ganglion and in essentially all of the inputs to
sympathetic preganglionic neurons supplying the adrenal medulla. These findings
are consistent with the hypothesis that all fast synaptic transmission in central
autonomic pathways may be mediated by either excitatory or inhibitory amino
acids. Furthermore, we showed a statistically significant difference in the
proportion of glutamate-immunoreactive inputs between sympathetic preganglionic
neurons projecting to the superior cervical ganglion and sympathoadrenal neurons
(data from Llewellyn-Smith et al. [Llewellyn-Smith, I.J., Phend, K.D., Minson,
J.B., Pilowsky, P.M., Chalmers, J.P., 1992. Glutamate immunoreactive synapses on
retrogradely labelled sympathetic neurons in rat thoracic spinal cord. Brain Res.
581, 67-80]), with preganglionics supplying the adrenal medulla receiving more
excitatory inputs than those supplying the superior cervical ganglion. This
increased excitatory input to sympathoadrenal neurons may explain the predominant
activation of these neurons following baroreceptor unloading.
PMID- 9760047
TI - Neurochemical markers in the nervous plexus of the canine glottis.
AB - The structure of the nervous network and the distribution of tyrosine hydroxylase
(TH)- and various neuropeptide-containing nerves were immunohistochemically
studied in the glottis of the dog. The nervous network in the glottis revealed
apparent regional differences in morphology. The nervous network in the
cartilaginous vocal fold of the posterior glottis consisted of nerve bundles
running parallel to the edge of the vocal fold. Only a small number of nerve
bundles were observed in the anterior glottis, specifically in membranous vocal
fold. In the subepithelial layer of the posterior glottis, a moderate number of
galanin (GAL)-immunoreactive nerve fibers were observed, while only a few fibers
were present in the anterior glottis. Numerous vasoactive intestinal peptide
(VIP)-, GAL-, methionine-enkephalin (ENK)- and TH-immunoreactive nerve fibers
were observed within and around the laryngeal submucosal seromucous gland. Many
TH- and neuropeptide Y (NPY)-immunoreactive fibers were arranged around the blood
vessels. In the epithelia, free nerve endings with immunoreactivity for substance
P (SP) and calcitonin gene-related peptide (CGRP) was observed. Furthermore,
nerve cell bodies with SP-, VIP-, GAL-, ENK-, and NPY-immunoreactivity were
observed in the deep region of the submucosal layer. The results from the present
study suggest that there is autonomic regulation of the glottis. Regional
structural differences in the nervous network of the glottis may reflect
functional differences.
PMID- 9760048
TI - Calcium transients evoked by action potentials in the somata of chick ciliary
neurons.
AB - The effect of action potentials on the calcium concentration in the somata of
chick ciliary neurons ([Ca2+]s) was determined by loading these with the calcium
indicator calcium green-1. Following trains of 1-10 impulses (30 Hz) to the
postganglionic nerve, the [Ca2+]s increased rapidly and then declined along a
single exponential with a time constant of 0.70 +/- 0.04 s (fast phase). After
trains of 20 or 50 impulses, the elevated [Ca2+]s declined as the sum of two
exponentials, with time constants of 0.78 +/- 0.12 s (fast phase) and 4.0 +/- 0.4
s (moderate phase). After a 600-impulse postganglionic train of impulses, the
elevated [Ca2+]s declined quickly over about 1 s, and then as the sum of two
exponentials: that of the moderate phase and a slower component with a time
constant of 109 +/- 16 s (slow phase). Similar time courses were observed
following stimuli to the preganglionic nerve. Caffeine (3 mM) and ryanodine (20
microM) both sped the fast phase and slowed the moderate phase of [Ca2+]s
decline. Carbonyl cyanide m-chlorophenyl hydrazone (CCCP, 2 microM) slowed the
slow phase, without affecting the other phases of decline. These results are
discussed in relation to identifying the mechanisms responsible for these
different phases of Ca2+ removal.
PMID- 9760049
TI - Effect of intravenous administration of melatonin on the efferent activity of the
adrenal nerve.
AB - The effect of intravenous administration of melatonin on the efferent activity of
the adrenal nerve was investigated in the rat. Intravenous infusion of 1 or 2 ng
melatonin resulted in a decrease, and 10 or 20 ng or larger amount of melatonin
caused an increase in the efferent activity of the adrenal nerve. The least
effective dose for the suppressive activity of melatonin was 100 pg and the
response is dose-related. Administration of either 1 ng or 10 ng of melatonin did
not change the plasma glucose concentration until 30 min after the
administration. Hepatic vagotomy eliminates the inhibitory effect of melatonin.
These results suggest that melatonin sensors in the hepato-portal region and
melatonin receptors in the SCN play important roles in the regulation of
sympathetic outflow to the adrenal medulla.
PMID- 9760050
TI - A target specific pathway from nitric oxide synthase immunoreactive preganglionic
sympathetic to superior cervical ganglion neurons innervating the submandibular
salivary gland.
AB - The correlations between nitric oxide synthase (NOS)-immunoreactive (NOS-ir)
preganglionic sympathetic neurons (PSNs) in the thoracic spinal cord and the
neurons in the superior cervical ganglia (SCG) were studied with special
reference to target specificity. NOS-ir neurons were distributed in the
intermediate gray of the spinal cord and most numerous in the intermediolateral
subnucleus of the PSNs. NOS-ir PSNs received direct synaptic contacts from
tyrosine hydroxylase-ir, 5-hydroxytryptamine-ir, gamma-amino butyric acid-ir, and
phosphate-activated glutaminase-ir axons. A majority of PSNs projecting to SCG
were NOS-ir but some were NOS-negative. Large SCG neurons surrounded by a dense
network of NOS-ir axons from PSNs projected to the submandibular salivary gland.
NPY-ir small SCG neurons devoid of NOS-ir PSN innervation projected to blood
vessels. SIF cells in the SCG were NOS-negative and provided with a meshwork of
NOS-ir axons. The present results suggest a subpopulation of SCG neurons may be
concerned with a distinct functional category in the rat under the influence of
NOS-ir preganglionic sympathetic neurons.
PMID- 9760051
TI - Extrinsic denervation increases myenteric nitric oxide synthase-containing
neurons and inhibitory neuromuscular transmission in guinea pig.
AB - Enteric nerves can function normally without connections with the central nervous
system. A contributing component of the functional autonomy exhibited by enteric
nerves is their plasticity. In the present study, the number of nitric oxide
synthase-immunoreactive (NOS-ir) myenteric neurons and inhibitory neuromuscular
transmission were studied in extrinsically denervated ileal segments. Segments of
ileum were extrinsically denervated by crushing the mesenteric blood vessels
supplying a loop of ileum in anesthetized guinea pigs. Some unoperated animals
were treated with capsaicin or 6-hydroxydopamine (6-OHDA) to disrupt primary
afferent and sympathetic nerves, respectively. NOS-ir was localized using
indirect immunofluorescence. Nerve-mediated relaxations of longitudinal muscle
were studied in vitro using standard methods. At 7 weeks after extrinsic
denervation there was a 93% increase in the number of NOS-ir myenteric neurons.
The number of neurons containing detectable vasoactive intestinal peptide-ir
neurons was not changed after extrinsic denervation. Neurogenic relaxations
caused by 10, 20 and 50 Hz transmural stimulation were larger in extrinsically
denervated tissues compared to control tissues. The NOS antagonist, nitro-L
arginine (300 microM) inhibited neurogenic relaxations in control and
extrinsically-denervated tissues. Capsaicin- but not 6-OHDA-treatment mimicked
the effects of extrinsic denervation on NOS-ir and neurogenic relaxations of the
longitudinal muscle. Active or passive properties of the longitudinal muscle were
unaffected by extrinsic denervation. These data indicate that extrinsic
denervation is associated with an increase in the number of myenteric neurons
expressing detectable NOS-ir and potentiation of inhibitory transmission to
longitudinal muscle. This effect is due to loss of extrinsic sensory nerves.
PMID- 9760052
TI - Effect of generalised sympathetic activation by cold pressor test on cerebral
haemodynamics in healthy humans.
AB - There is no general agreement regarding several aspects of the role of the
sympathetic system on cerebral haemodynamics such as extent of effectiveness,
operational range and site of action. This study was planned to identify the
effect of a generalised sympathetic activation on the cerebral haemodynamics in
healthy humans before it is masked by secondary corrections, metabolic or
myogenic in nature. A total of 35 healthy volunteers aged 20-35 underwent a 5 min
lasting cold pressor test (CPT) performed on their left hand. The cerebral blood
flow (CBF) velocity in the middle cerebral arteries and arterial blood pressure
were recorded with transcranial Doppler sonography and with a non-invasive finger
cuff method, respectively. The ratio of arterial blood pressure to mean blood
velocity (ABP/Vm) and Pulsatility Index (PI) were calculated throughout each
trial. CPT induced an increase in mean ABP (range 2-54 mmHg depending on the
subject) and only a slight, though significant, increase in blood velocity in the
middle cerebral artery (+2.4 and +4.4% on ipsi- and contralateral side,
respectively). During CPT, the ratio ABP/Vm increased and PI decreased in all
subjects on both sides. These changes began simultaneously with the increase in
blood pressure. The increase in ABP/Vm ratio is attributed to an increase in the
cerebrovascular resistance, while the concomitant reduction in PI is interpreted
as due to the reduction in the compliance of the middle cerebral artery. The
results suggest that generalised increases in the sympathetic discharge, causing
increases in ABP, can prevent concomitant increases in CBF by acting on both
small resistance and large compliant vessels. This effect is also present when a
slight increase in blood pressure occurs, which suggests a moderate increase in
the sympathetic discharge, i.e. when ABP remains far below the upper limit of CBF
autoregulation.
PMID- 9760054
TI - Organ and development related difference in tissue norepinephrine concentrations
in Dahl rats.
AB - To determine organ and development related differences in tissue norepinephrine
concentration (tNE) in Dahl salt-sensitive (S) and -resistant (R) rats, we
measured the tNE of 16 organs, including the heart (left ventricle), kidney,
cerebrum, brain stem, stomach, jejunum, ileum, colon, spleen, pancreas, liver,
aorta, lung, bone, salivary gland, and muscle, at 1, 3, 5, 7, 9, 11 weeks old.
Large differences were found in tNE among the organs of both S and R rats,
ranging from 4.0 +/- 1.1 ng/g tissue (the bone of S rats) to 1234.8 +/- 32.5 ng/g
tissue (the salivary gland of R rats). tNE in R rats increased development
dependently in 12 of 16 organs, but did not significantly change in the other
three organs, and decreased in the bone. On the other hand, the development
dependent increase in tNE was suppressed in S rats, and the tNE values of S rats
were significantly lower than those of R rats in 14 of 16 organs. To eliminate
the baroreflexive effects on tNE, another group of 5-week-old S and R rats were
subjected to sinoaortic denervation (SAD) or the sham operation. The tNE was
measured in 10 organs in these animals at 9 weeks old. SAD did not alter the tNE
in most of the organs in both S and R rats. There was no significant differences
in mean arterial pressure (MAP) between S and R rats with baroreceptor intact at
9 weeks old. SAD slightly but significantly increased MAP in S rats, whereas not
in R rats. There was no significant differences in plasma NE concentration (pNE)
between S and R rats with the baroreceptor intact. SAD did not alter pNE in S or
R rats. These results demonstrate that variations of the tNE were dependent on
the organ and development. Many organs of S rats had lower tNE than those of R
rats. The developmental-dependent increases in tNE in S rats were suppressed,
compared with those in R rats. These tNE behaviors in S rats may not be related
to blood pressure or baroreflex sensitivity, but might be involved in an abnormal
sympathetic nerve activity.
PMID- 9760055
TI - Magnitude of skin vasomotor reflex represents the intensity of nociception under
general anesthesia.
AB - Because nociceptive stimuli induce the skin vasomotor reflex (SVmR), the
assessment of the SVmR would be a useful indicator to represent nociception. We
examined 39 adult patients for the relationship between the magnitude of the SVmR
and the intensity of nociceptive stimulus that induced the SVmR. Under oxygen
nitrous oxide (50%) and sevoflurane anesthesia, the SVmR was induced by an
electrical impulse to the ulnar nerve and detected by a laser Doppler flowmeter.
Study 1: under the end-tidal concentrations of sevoflurane at 1.2% (n = 10), 1.7%
(n = 9) or 2.2% (n = 10), the SVmR was tested by a 2-s, 50-Hz tetanic electrical
impulse with a current intensity changing (40, 50 or 60 mA) in a randomized
order. Study 2: under the end-tidal concentration of sevoflurane at 1.7% (n =
10), the SVmR testing was performed with a 50-mA, 50-Hz tetanic electrical
impulse with the current duration changing (2, 3 or 4 s) in a randomized order.
The studies demonstrated significant correlations of (1) the current intensity
which induces the skin vasomotor reflex (SVmR) vs. the magnitude of the SVmR
under the three different anesthesia depths, (2) the anesthesia depth vs. the
magnitude of the SVmR (inverse proportion) under the same current intensity and
(3) the duration of electrostimulation vs. the magnitude of the SVmR. Thus, the
SVmR could be helpful for the objective assessment of nociception and anti
nociceptive effects in individual cases.
PMID- 9760053
TI - I1-imidazoline receptors and cholinergic outflow to the airways.
AB - We examined the role of I1-imidazoline receptors in the control of airway
function, by testing the effects of systemic administration of the I1-imidazoline
agonist moxonidine on reflex responses of tracheal smooth muscle (TSM) tone to
either lung deflation or mechanical stimulation of intrapulmonary rapidly
adapting receptors. Experiments were performed in either alpha-chloralose
anaesthetized or decorticate, paralyzed and mechanically ventilated beagle dogs.
Moxonidine (10-100 microg/kg) administered via three different routes (the
femoral vein, muscular branch of superior thyroid artery, and vertebral artery)
attenuated TSM responses to stimulation of airway sensory nerve fibers by two
different ways, and caused a decrease in arterial pressure and heart rate. These
effects were dose-dependent, and were significantly reversed by efaroxan (an I1
imidazoline and alpha2-adrenergic blocker) administered via the vertebral artery.
Intravertebral efaroxan abolished the hemodynamic effects of moxonidine.
Intravenous moxonidine (10-100 microg/kg) did not alter airway smooth muscle
responses to electrical stimulation of the peripheral vagus nerve. In addition,
in vitro moxonidine (1-100 microg/ml) had no effect on contractile responses to
increasing doses of acetylcholine. These findings indicate that moxonidine may
act at a central site to suppress reflex airway constriction, even when given
into the systemic circulation. Given the presence of I1-imidazoline sites and
alpha2-adrenergic receptors in brain regions participating in airway reflexes,
these receptor classes may be involved in brainstem control of the cholinergic
outflow to the airways.
PMID- 9760056
TI - Expression and physiological actions of neuropeptide Y in guinea pig
parasympathetic cardiac ganglia.
AB - Guinea pig atrial whole mount preparations containing the parasympathetic cardiac
ganglia were used to establish the expression, distribution and actions of
neuropeptide Y (NPY) in atrial tissues. NPY-immunoreactive fibers densely
innervated the atrial myocardium and blood vessels. Fibers containing NPY also
innervated intrinsic parasympathetic cardiac neurons. Four percent of the cardiac
neurons, identified using microtubule associated protein-2 antiserum, were NPY
positive. An endogenous source of NPY was confirmed with reverse transcription
PCR which demonstrated the presence of proNPY mRNA. Sixty percent of the
parasympathetic cardiac neurons were hyperpolarized by local application of NPY.
NPY also decreased the amplitude and duration of the action potential after
hyperpolarization in 60% of the neurons and decreased the fast excitatory
postsynaptic potential in about 50% of the cells. These observations indicate
that NPY is anatomically positioned to directly alter the output of the
parasympathetic cardiac ganglia either by hyperpolarizing the cardiac neurons or
by decreasing the fast synaptic input which drives individual neurons.
PMID- 9760057
TI - Further characterization of stimulus interaction of cat carotid chemoreceptors.
AB - The hypothesis that the maximal response to pCO2 of carotid body chemoreceptors
would be the same regardless of pO2, if the receptor molecule behaves like a
hemoglobin molecule, was investigated using single or a few fiber carotid body
chemoreceptors in cats in vivo which were anesthetized and artificially
ventilated. In one series, graded levels of CO2 inhalation in steady-state at
p(a)O2 = 354 +/- 19 Torr showed a linear response from 1 to 20.1 +/- 2.3 imp/s
for p(a)CO2 increase from 32 to 178 +/- 18 Torr, and at p(a)O2 of 48 +/- 3.8
Torr, from 3.8 to 18.6 +/- 1.7 imp/s for p(a)CO2 increase from 21 to 109 +/- 11
Torr, levelling off thereafter. In another series of multi-fiber preparation,
close intra-arterial injection of blood plus saline containing pCO2 of about 270
Torr gave peak responses of 44 +/- 9, 42 +/- 6 and 42 +/- 7 imp/s at p(a)O2 of 40
+/- 4, 82 +/- 6 and 388 +/- 18 Torr, respectively. Thus, the chemosensory
responses to p(a)CO2 reached the same level of maximal activity regardless of
p(a)O2. Taken together, the maximal responses in both steady-state and transient
state to p(a)CO2 appeared to be the same at hypoxic and hyperoxic p(a)O2. This
stimulus-response relationship of the receptor molecule is analogous to O2-CO2
interaction with hemoglobin molecule with a Bohr effect, reaching a saturation
point at a finite pO2.
PMID- 9760058
TI - Pig, donkey and buffalo meat as a source of some coccidian parasites infecting
dogs.
AB - Experimental infection of dogs with meat samples (oesophagus, heart and
diaphragm) from each of 105 pigs, 11 donkeys and 17 Egyptian water buffaloes
indicated that they contained the infective stages of some coccidian parasites of
dogs. The dogs which were fed pig meat shed in their faeces Isospora ohioensis,
I. canis oocysts and Sarcocystis miescheriana sporocysts after prepatent periods
of 3-5, 4-7 and 9-10 days, respectively. The dogs which were fed donkey meat
excreted only I. ohioensis oocysts and Sarcocystis bertrami sporocysts after
prepatent periods of 3 and 11 days, respectively. However, the dogs which were
fed buffalo meat shed in their faeces I. ohioensis, I. canis and Hammondia
heydorni oocysts with prepatent periods of 1, 1 and 7 days, respectively.
PMID- 9760059
TI - Selection and development of a Spanish precocious strain of Eimeria necatrix.
AB - A precocious line of Eimeria necatrix (PEN E-281/20) with an abbreviated life
cycle was derived from a Spanish field strain (E-281) by repeated passages of the
first shed oocysts recovered from the caecal contents of previously infected
chickens. After 20 passages, the 'useful' prepatent period (time from infection
to obtaining sufficient oocysts to repassage) of the parasite was reduced by 30 h
(from 148 to 118 h). The earliest oocysts found in the caecal content were 114 h
postinfection (hpi), on the 19th passage. The pathogenicity of the parasite was
reduced in comparison with the parent strain, its immunogenicity against
homologous and heterologous strains was maintained and its reproductive capacity
was similar to or higher than that of the parent strain. Compared with the parent
strain, the second generation of schizonts was reduced in size (reduced
pathogenicity), third generation schizonts were bigger and with more merozoites
(maintenance of the reproductive index) and the life cycle progressed faster from
the second generation of schizonts (reduction of prepatent period). Complete
second schizogony, from trophozoites to mature schizonts was observed frequently
in the caeca of birds infected with both parent and precocious lines.
PMID- 9760060
TI - Diagnosis of porcine cysticercosis: a comparative study of serological tests for
detection of circulating antibody and viable parasites.
AB - Epidemiological studies of porcine cysticercosis require identification of pigs
harbouring viable Taenia solium cysticerci and estimates of the degree of
exposure to the parasite in the pig population destined for human consumption.
Identification of infected pigs with viable larvae is achieved through detection
of their secretory products. However, detectable levels of circulating antibody
may also be present in the absence of viable larvae. In this study, both types of
tests have been evaluated in groups of pigs experimentally infected with T.
solium. Detection of viable cysticerci was achieved using a monoclonal antibody
based (HP10) antigen capture assay. HP10 epitope-bearing antigens have now been
demonstrated in T. solium and T. crassiceps cyst fluid and excretion/secretions.
Serum antibodies were measured in ELISA assays using two parasite preparations as
antigens; T. solium cyst fluid and T. crassiceps cyst fluid antigens bearing the
HP10 epitope. Low-background values were obtained with sera from non-infected
animals in all the assays used. In heavily infected pigs, both antigens and
antibodies were detected at least 29 days and up to 200 days post-infection (pi),
while in lightly infected pigs antigen and antibodies were first observed between
61-97 days pi. Thus, the levels of the serum antigen and antibody varied with the
intensity of the infection.
PMID- 9760061
TI - Helminth and protozoan gastrointestinal tract parasites in captive and wild
trapped African non-human primates.
AB - The objective of this study was to investigate the gastro-intestinal (GIT)
parasites commonly occurring in captive and wild-trapped (WT) non-human primates
(baboons, vervets and Sykes) in Kenya and compare their prevalence. Three hundred
and fifteen faecal samples were subjected to a battery of diagnostic tests,
namely, direct smear, modified formal ether sedimentation, Kato thick smear,
Harada-Mori techniques for parasite detection and culture to facilitate nematode
larvae identification. Of these, 203 (64.4%) harboured helminths and 54 (17.1%)
had protozoa. The helminth parasites comprised Strongyloides fulleborni 141
(44.8%), Trichuris trichuira 200 (63.5,%), Oesophagostomum sp. 48 (15.2%),
Trichostrongylus sp. 73 (23.2%), Enterobius vermicularis 44 (14.0%), Schistosoma
mansoni 4/92 (4.3%) and Streptopharagus sp. 68 (21.6%). Protozoan parasites
consisted of Entamoeba coli 204 (64.8%), Balantidium coli 127 (40.3%) and
Entamoeba histolytica 78 (24.8%). Both WT and colony-borne (CB) primates had
similar species of parasites, but higher prevalences of protozoan infection were
observed in CB baboons while helminth infections were relatively more common in
WT primates. Some of the parasites observed in this study are reported to be
zoonotic in various parasitological literatures. Chemoprophylaxis and other
managerial practices were believed to be responsible for the lower worm
prevalence in CB primates. Similar intervention against protozoa and other agents
will not only improve primate health, but also increase safety to animal handlers
and colony workers.
PMID- 9760062
TI - Natural prevalence of infection with Ehrlichia (Cytoecetes) phagocytophila of
Ixodes ricinus ticks in Scotland.
AB - Ixodes ricinus nymphs and adults were collected from vegetation and from sheep at
four sites in Scotland typical of areas endemic for tick-borne fever in sheep
caused by infection with Ehrlichia (Cytoecetes) phagocytophila (Rickettsiales).
The great majority of ticks examined was from woodland sites adjacent to sheep
farms where there was a high probability of them feeding on roe deer (Capreolus
capreolus) in a non-domestic focus of infestation and infection. Ticks were
examined for infection by five methods. Batches of ticks were examined either by
feeding on susceptible sheep or by feeding on rabbits and then prepared as
stabilate which was inoculated into susceptible sheep. The sheep were monitored
for clinical signs of tick borne fever. Batches of ticks were examined by
polymerase chain reaction for Ehrlichia phagocytophila. Salivary glands were
dissected out and stained by the Feulgen method to detect Ehrlichia masses, and
were examined by indirect fluorescent antibody test. Each of the methods detected
infection in ticks and the prevalence of infection in nymphs with the various
methods ranged from >0.25% to 2.0%. Small samples of adults examined by Feulgen
staining of salivary glands indicated infection prevalences of 2.1% in males and
1.6% in females. It is considered that these low infection prevalences may be
typical of natural foci of infection where deer could be a major host of ticks
and E. phagocytophila.
PMID- 9760063
TI - Efficacy of ivermectin in a controlled release formulation against Psoroptes ovis
(Hering, 1838) gervais, 1841 (Acari: Psoroptidae) on sheep.
AB - Three trials including 42 sheep were conducted in Brazil or Germany to evaluate
the therapeutic (two trials) and prophylactic (one trial) efficacy of an
ivermectin controlled release capsule (CRC) against Psoroptes ovis infestation.
In one therapeutic trial naturally infested sheep were used while in the other
trials infestations were experimentally induced. In each trial half of the
animals were treated on Day 0 with one ivermectin controlled release capsule that
delivers ivermectin at a rate of 1.6 mg/day for approximately 100 days, that is
20 mcg/kg/day to a 80 kg animal, while the other half remained untreated. In both
therapeutic trials mites were counted in skin scrapings and their presence was
recorded at predilection sites one day before treatment and at weekly intervals
from Day 7 to Day 56. In the trial conducted to evaluate the prophylactic
efficacy the sheep were experimentally infested with P. ovis 21 and 28 days post
treatment and mites were counted and recorded at predilection sites on Days 42,
49 and 56. The ivermectin controlled release capsule was completely effective in
eliminating the P. ovis mites within 28 days of administration and it prevented
the establishment of an infestation of P. ovis induced 21 and 28 days after
administration.
PMID- 9760064
TI - Sex differences in the disposition of albendazole metabolites in sheep.
AB - Sex differences in the disposition of albendazole metabolites in sheep after oral
administration of 20 mg/kg of netobimin have been studied. Some kinetic
parameters of both metabolites show statistical differences between sexes; the
sulphoxide and sulphone t1/2beta and MRT were lower in male animals than in
females. Peak concentrations and AUC of sulphone metabolites were higher in males
suggesting a greater oxidation rate compared with females. Urine excretion of
albendazole metabolites, sulphoxide, sulphone, and amino sulphone appeared to be
greater in female sheep than in males, mainly the sulphoxide metabolite. These
differences between sexes can be caused by male sexual hormones, because
testosterone and progesterone can induce or inhibit the microsomal Cytochrome
P450 metabolism. Plasma protein-binding of albendazole sulphoxide and albendazole
sulphone has been studied between male and female sheep, also their binding to
sheep albumin and globulins. Both albendazole metabolites readily bind to sheep
albumin and globulins. Male animals show a significantly lower binding of
albendazole metabolites than females. These differences could be responsible for
the non-esterified fatty acids (NEFA) present in the plasma. Males have
significantly higher plasma levels of NEFA than females and which may compete
with albumin for binding to albendazole metabolites.
PMID- 9760065
TI - Seroprevalence of Taenia solium cysticercosis in pigs in a rural community of
Honduras.
AB - Several retrospective studies have shown that human Taenia solium cysticercosis
is endemic in Honduras, but very few reports of porcine cysticercosis in rural
communities have been published. To determine the local prevalence of this
disease in pigs, a serological survey has been undertaken in a rural community,
Salama, in the Department of Olancho in central Honduras. Eighty-five families
raising pigs in the community were randomly selected and sera were obtained from
pigs older than one month of age. The sera were examined by the enzyme-linked
immunoelectrotransfer blot assay (EITB). Of 192 porcine sera, 27.1% (52) were
positive by the EITB. Seropositivity did not correlate with age and sex by
statistical analysis. With respect to the number and the frequency of recognition
of the seven diagnostic glycoprotein bands in the EITB, 67.3% of the positive
serum specimens recognized only one band and 80.8% of them recognized GP42-39.
Since recognition of GP42-39 has been reported as a characteristic of late
infection, these results suggest that most of the seropositive pigs were in the
late stage of infection (more than 5-8 weeks postinfection). It seems that pigs
in this community may be infected with this parasite soon after the birth and be
in a hyperendemic steady state. In view of a high prevalence of antibodies to T.
solium in pigs or characteristics of the antigen detected by the EITB, the
infection pressure of T. solium appears to be very high in this community. This
is probably the case in most of the communities in Honduras.
PMID- 9760069
TI - Solitary intracranial plasmacytoma: case report and review of management.
AB - A rare occurrence of solitary intracranial plasmacytoma arising from the meninges
over the left hemisphere is reported. Clinical features and management of the
case are described with review of literature.
PMID- 9760066
TI - Growth inhibition of newly established human glioma cell lines by leukemia
inhibitory factor.
AB - We have established three new cell lines deriving from malignant human gliomas.
The cell lines were described in terms of both morphology and growth
characteristics. Most cells in all three cell lines expressed the neuroepithelial
marker protein GFAP. In terms of growth characteristics, the cells showed only
slight differences. The cell lines showed no expression of the neural form of the
c-src gene, pp60c-srcN, but did express the ubiquitous form, pp60c-src. The
established glioma cell lines were also examined for expression of members of the
neuropoietic cytokine family, CNTF and LIF, and their respective receptor
components CNTFRalpha, LIFRbeta and gp130. With the exception of CNTFRalpha both
the ligands and their receptor components were expressed in similar amounts in
all three cell lines. The presence of ligand and receptor prompted us to study
the effects of exogenously supplied factors on the growth of the glioma cell
lines. Whereas LIF induced a high c-fos expression, only low c-fos induction was
observed upon CNTF treatment. Accordingly, CNTF did not have any noticeable
effects on glioma cell growth in culture, while LIF mediated an inhibiting effect
on the growth of the three glioma cell lines in culture.
PMID- 9760070
TI - Clusters of histologic characteristics in children with infratentorial neuroglial
tumors. The Childhood Brain Tumor Consortium.
AB - Five quantitative histologic factors, differing linear combinations of 26
reliably recognized histologic features, account for much of the histologic
variance in 1068 children with infratentorial neuroglial tumors in the Childhood
Brain Tumor Consortium (CBTC) database. In this study, we used the scores on the
Spongy, Proliferative, Ring, Fibrillary, and Nuclear factors in cluster analyses
and identified 11 clusters of children's tumors. Each had statistically
significant differences in histology and relative histologic homogeneity. Three
clusters had ependymoma-like histologic features; 4 had astrocytoma-like
features; and 4 had primitive neuroectodermal-like (PNET or medulloblastoma)
features. Each cluster had a unique high/low mean factor score pattern. Multiple
operative and other clinical features characterized the three groups of clusters.
We used Kaplan-Meier survival models to test for differences in survival among
clusters and proportional hazards survival models to adjust for associated
covariates. Among the 'ependymoma' clusters the 5 year survival probability
ranged from 0.25 to 0.54. Among the 4 'astrocytoma' clusters, 5 year survival
probability ranged from 0.59 to 0.94. The 5 year survival probability for the
'medulloblastoma' clusters ranged from 0.20 to 0.44. Within the three groups,
clusters had differing covariates associated with survival. The tumor clusters
identified in this study ensure relatively homogeneous histologic subsets. The
five factor scores of a child's tumor provide the basis for finding the cluster
nearest to that tumor. We propose that this tumor clustering strategy be employed
for selection of children and for analyses of therapeutic clinical trials.
PMID- 9760067
TI - Chemosensitivity of human malignant glioma: modulation by p53 gene transfer.
AB - Loss of wild-type p53 activity is one of the most common molecular abnormalities
in human cancers including malignant gliomas. The p53 status is also thought to
modulate sensitivity to irradiation and chemotherapy. Here, we studied the effect
of a p53 gene transfer on the chemosensitivity of three human glioma cell lines
with different endogenous p53 status (LN-229, wild-type; LN-18, mutant; LN-308,
deleted), using the murine temperature-sensitive p53 val135 mutant. Expression of
mutant p53 enhanced proliferation of LN-308 cells but reduced proliferation in
the other cell lines. Expression of wild-type p53 caused reversible growth arrest
of all cell lines but failed to induce apoptosis. Growth arrest induced by wild
type p53 was associated with strong induction of p21 expression. Strong induction
of BAX expression and loss of BCL-2 expression, which are associated with p53
dependent apoptosis rather than growth arrest, were not observed. Wild-type p53
failed to sensitize glioma cells to cytotoxic drugs including BCNU, cytarabine,
doxorubicin, teniposide and vincristine. The combined effects of wild-type p53
gene transfer and drug treatment were less than additive rather than synergistic,
suggesting that the intracellular cascades activated by p53 and chemotherapy are
redundant. Unexpectedly, forced expression of mutant p53 modulated drug
sensitivity in that it enhanced the toxicity of some drugs but attenuated the
effects of others. These effects may represent a dominant negative effect of
mutant p53 in LN-229 cells which have wild-type p53 activity but must be
considered a gain of function-type effect in the other two cell lines which have
no wild-type p53 activity. Importantly, no clear-cut pattern emerged among the
three cell lines studied. We conclude that somatic gene therapy based on the
reintroduction of p53 will limit the proliferation of human malignant glioma
cells but is unlikely to induce clinically relevant sensitization to chemotherapy
in these tumors.
PMID- 9760068
TI - A dominant-negative mutant of the platelet-derived growth factor A-chain
increases survival of hamsters implanted intracerebrally with the highly invasive
CxT24-neo3 glioblastoma cell.
AB - Evidence is accumulating to suggest a role for PDGF in stimulating malignant
growth in astrocytoma, although it has been obtained using model systems (growth
in 2-dimensional cell culture, athymic nude mice) that do not assess the complex
interactions of these tumors with normal brain tissue. In the current study, the
highly invasive hamster glioblastoma cell line CxT24-neo3 was used as a model to
study the role of platelet-derived growth factor (PDGF) in mediating malignant
growth both in vitro and in vivo when implanted directly into the right lateral
ventricle of the brain. Co-expression of PDGF B-chain mRNA and PDGF alpha
receptors was detected in these cells, indicating potential for autocrine
activation of their growth. CxT24-neo3 cells transfected with wild-type and
receptor binding-deficient forms of the PDGF A- and B-chains displayed
alterations in their abilities to grow as three-dimensional spheroids, with
overexpression of wild-type B-chain resulting in increased spheroid formation,
but a decreased rate of spheroid growth. Influence of these PDGF polypeptides on
tumor invasion and survival time in vivo was evaluated following implantation of
these spheroids in the brain. While all hamsters implanted with control spheroids
died within 21 d (average 17 d), those implanted with cells expressing the
receptor binding-deficient A-chain survived for much greater periods of time
(average 80 d). Modest increases in survival were also seen in cells stably
expressing wild-type A-chain (25 d) and mutant B-chain (26 d) proteins. The
present study suggests an important role of PDGF in mediating the malignant
growth of the CxT24-neo3 cell line in cerebral cortex, possibly via paracrine
interactions with normal cortical cell types (i.e., glia, neurons).
PMID- 9760071
TI - Atypical and malignant meningiomas: an outcome report of seventeen cases.
AB - Limited data are available concerning the outcome of patients with atypical and
malignant meningiomas. We therefore analyzed the outcome of seventeen patients
with meningiomas (9 atypical; 8 malignant) at Thomas Jefferson University
Hospital between 1973 and 1996. Strict adherence to the 1993 WHO criteria for the
typing of CNS tumors was maintained. The median potential follow-up period for
all patients was 87 months. The age at diagnosis ranged from 22 to 72 (mean 51.8
years). There were 5 males and 12 females. The mean tumor diameter was 4.45 cm.
Of the 16 cases where the extent of surgical resection was known, 4 were partial
and 12 were complete resections. Six patients (35%) had dural or cortical
invasion by tumor. Fifteen patients received postoperative megavoltage photon
irradiation (mean 61 Gy). One of these fifteen pts. received an additional 20 Gy
with Au-198 implantation and 1 received post-radiation chemotherapy for recurrent
disease. The overall survival rate for all patients at 5 and 10 years were 87%
and 58% respectively. The 5- and 10-year survival rates for atypical meningiomas
were 87% and 58%; for malignant meningiomas the survival rates were 60% and 60%
respectively. Five patients (30%) have died. Three of these 5 patients initially
received less than 54 Gy to the tumor bed and have died of recurrent disease.
Local disease progression was documented in 11 patients (65%) after surgery and
in 3 patients (18%) after radiation. There was an improvement in performance
status in 3 (18%) patients with a decline and no change seen in 1 (6%) and 13
(77%) respectively after receiving radiation. There appeared to be no difference
in survival in patients as a function of dural or cortical invasion. Long term
survival is possible for patients with atypical and malignant meningiomas treated
with surgery and post-operative radiation. We are unable to distinguish a
difference in outcome between these two pathological entities. Dural and cortical
invasion were not associated with a decrease in survival. In addition, improved
tumor control and survival may be associated with increased radiation dose.
PMID- 9760072
TI - Synchronous radiochemotherapy in unfavorable brain tumors of children and young
adults.
AB - The prognosis of patients with incompletely resected malignant brain tumors is
almost fatal. In an attempt to improve the outcome of children and young adults
with unfavorable brain tumors an intensive multimodal therapeutic strategy was
developed combining simultaneous (hyper)fractionated external beam irradiation
and conventional adjuvant chemotherapy after initial surgery. 17 patients aged
between 2.10 and 25.11 years were entered into the study. 16/17 patients were
treated according to the German/Austrian Pediatric Brain Tumor Study Group
multicenter trial HIT '91. They are not protocol patients of this HIT '91 trial.
Induction chemotherapy consisted of 2 courses of ifosfamide (3 g/m2/d) on days 1
3, etoposide (150 mg/m2/d) on days 4-6, methotrexate (5 g/m2) on days 15 and 22,
cisplatin (40 mg/m2/d) and cytarabine (400 mg/m2/d) on days 29-31. Three weeks
after the last dose of cisplatin/cytarabine the second course of chemotherapy was
started. The last patient entered into the study received a modified therapy
containing ifosfamide, cisplatin and etoposide. Synchronously at a median of 12
days after initiation of chemotherapy 12/17 patients received local radiotherapy
(6000-7040 cGy) to the brain and 5/17 patients craniospinal irradiation (3520 cGy
with a tumor boost of 1400-2000 cGy). 4-6 weeks after completion of the second
course of chemotherapy maintenance therapy was started with carmustine (CCNU) (75
mg/m2) and carboplatin (400 mg/m2) each on day 1 and vincristine (1.5 mg/m2) on
day 1, 8, 15. This course was repeated eight times every six weeks. 9/17 patients
are alive at a median follow-up of 25 months (range 5-50) with 4 complete
remissions, 2 partial remissions and 1 stable disease lasting 42+ months. Two
patients, who initially had stable disease, progressed, but are still alive at
31+ and 41+ months after diagnosis. Median progression-free survival and median
overall survival is 19 and 36 months, respectively. Hematologic and methotrexate
induced toxicity were severe and resulted in one therapy-related death. However,
radiotherapy concomitant to chemotherapy appears to be an effective method of
treatment for brain tumors with poor prognosis, though toxicity is severe in some
cases.
PMID- 9760075
TI - Identification of CNS neurons innervating the rat prostate: a transneuronal
tracing study using pseudorabies virus.
AB - The spinal and brain neurons that innervate the rat prostate were identified
using the transneuronal tracing technique. Three groups of rats were prepared:
(1) nerve intact, (2) bilateral pelvic nerve cut and right hypogastric nerve cut
and (3) bilateral hypogastric nerve cut and right pelvic nerve cut. Pseudorabies
virus (PRV) was injected into the ventral prostate on the left side. After 2-4
days, the rats were perfused transcardially under deep anesthesia and the spinal
cord and brain removed. PRV-labelled cells were identified using
immunohistochemistry. After 3 days survival, sympathetic and parasympathetic
preganglionic neurons were labelled with PRV. In addition, spinal interneurons
were found in the dorsal gray commissure (DGC) of T13-S1. Rats with only one
hypogastric nerve intact resulted in spinal labelling of sympathetic
preganglionic neurons in the DGC and ipsilateral intermediolateral cell column
(IML). In addition, many spinal interneurons were found from L1 to L6 in the
medial gray. Rats with only one pelvic nerve intact displayed PRV-labelled cells
in the parasympathetic preganglionic nucleus ipsilateral to the injection site.
Spinal interneurons were present in the region of the IML and in the medial cord.
In the brain, areas predominately labelled with PRV included the nucleus
gigantocellularis and paragigantocellularis, raphe magnus, raphe pallidus, A5,
Barrington's nucleus, central gray, ventral tegmental area, the paraventricular
nucleus of the hypothalamus, lateral hypothalamus and medial preoptic area. These
data demonstrate the sympathetic and parasympathetic spinal circuits and
demonstrate the overlap of supraspinal innervation of the spinal interneurons.
PMID- 9760073
TI - Significant change in tests of neurological impairment in patients with brain
tumours.
AB - There is a need for valid objective tests of neurological improvement or
deterioration to more accurately define response or progression in phase II
studies of malignant glioma. The Edinburgh Functional Impairment Tests (EFIT)
incorporate objective measures of upper and lower limb function, memory and a
rating scale for dysphasia. We examined the intra-observer repeatability of the
(EFIT) 24 hours apart in 55 patients with brain tumors and stable neurological
disease and the inter-rater repeatability in 33 patients in the perioperative
period (54 dual assessments). Intra-observer studies of the four subtests, failed
to demonstrate any learning effect and showed close agreement. Inter-rater
studies were affected by a treatment effect (steroids) and identified slight
inter-rater bias for the ten meter walk. Altman-Bland plots showed that the level
of agreement was less good in patients with more severe impairment. Correction
for the severity of handicap was possible using a simple formulae: (timed tests:
[rater 1 - rater 2]/[rater 1 + rater 2], Williams Delayed Recall Test [WDRT]
(rater 1 - 2/81). Using this correction, all intra- and inter-rater variance of
patients tested within 12 hours were < 0.2. A change of > or = 0.2 for the timed
tests and WDRT, and a change in dysphasia score of > or = 2, represent a
significant change in impairment using the EFIT. The EFIT should be a useful
addition in phase II studies where objectively recording response or time to
progression is important.
PMID- 9760074
TI - Transitional cell carcinoma presenting as a solitary brain lesion: a case report
and review of the world literature.
AB - Transitional cell carcinoma of the urinary tract will account for roughly 50,000
new cases of cancer in the US this year. Metastatic involvement to the brain is
uncommon with this malignancy. When it does occur, it is usually in the setting
of widespread metastatic disease. A rare case of transitional cell carcinoma of
the bladder presenting as a solitary brain lesion is reported. In addition, we
reviewed the world literature regarding transitional cell carcinoma metastatic to
the central nervous system. Our review suggests that metastatic transitional cell
carcinoma of the central nervous system has become increasingly common as more
effective chemotherapeutic regimens have been developed to control the primary
disease. The recent literature also suggests that, much like other metastatic
disease to the brain, outcome and survival in patients without widespread disease
is improved by aggressive surgical and oncological management.
PMID- 9760076
TI - AT1 receptors mediate chronic central nervous system AII hypertension in rats fed
high sodium chloride diet from weaning.
AB - CNS angiotensin II (AII) hypertension is induced by chronic, low dose
intracerebroventricular (ICV) AII infusion only in rats raised on a relatively
high sodium chloride diet (250 meq kg(-1)food) from weaning. This experimental
model of hypertension is dependent upon renal sympathetic innervation and
associated with neurogenic sodium retention. This study determined whether AT1
and/or AT2 receptor subtypes in the CNS mediate this neurogenic ICV AII
hypertension. Rats were weaned at 21 days of age and fed a 1.5% sodium chloride
diet for 10-12 weeks. At adulthood, animals were instrumented with CNS lateral
ventricular cannulas, femoral arterial and vein catheters and housed in metabolic
pens for chronic study. Low dose ICV AII infusion (20 ng min(-1) )increased mean
arterial pressure by 12+/-2 mm Hg and decreased urinary sodium excretion for
three consecutive days. Subsequent ICV AT1 blockade with losartan abolished both
the pressor and antinatriuretic responses to low dose ICV AII. In contrast, ICV
AT2 receptor blockade with PD 123319 did not affect either angiotensin induced
pressor or antinatriuretic responses. Following cessation of ICV AII infusion,
arterial pressure and sodium excretion returned to values not significantly
different from control in both groups of rats. These data confirm that low dose
ICV AII causes hypertension and sodium retention in rats raised from early age on
moderately elevated sodium intakes. This AII mediated neurogenic hypertension and
antinatriuresis is transduced by activation of CNS AT1 receptors and not by
activation of central AT2 receptors.
PMID- 9760077
TI - Pharmacological properties of the CO2/H+-sensitive area in the ventral medullary
surface assessed by the effects of chemical stimulation on respiration.
AB - We recently discovered that CO2/H+-sensitive neurons in the ventral medullary
surface (VMS) are immunoreactive to glutamate, glutamic acid decarboxylase (GAD),
calcineurin and cAMP. We then tested the hypothesis that glutamate, GABA,
calcineurin and cAMP affect the activity of CO2/H+-sensitive neurons in the VMS.
Using male Wistar rats anesthetized with urethane and pentobarbital, we checked
for changes in relative tidal volume (VT) and respiratory frequency (f) in
response to injecting the VMS with a variety of test agents dissolved in mock
CSF. Respiratory changes occurred immediately and were dose-dependent. (1) 200
1600 pmol Glutamate increased VT but decreased f. The glutamate effect was never
abolished by concomitant injection of AP5, a NMDA receptor antagonist, but was
abolished by CNQX, an AMPA receptor antagonist, indicating predominance of AMPA
receptors in the CO2/H+-sensitive neurons in the VMS. (2) 200-1600 pmol GABA
decreased both VT and f. The GABA effect was never abolished by concomitant
injection of saclofen, a GABA(B) receptor antagonist, but was abolished by
bicuculline, a GABA(A) receptor antagonist, indicating predominance of GABA(A)
receptors in the CO2/H+-sensitive neurons in the VMS. (3) 4-32 microg
Calcineurin, a Ca2+/calmodulin-dependent protein phosphatase 2B, and 200-1600
pmol FK506, selective inhibitor of calcineurin, had no effect on respiration when
they were applied extracellularly, but 400-3200 pmol BAPTA-AM, an intracellular
Ca2+-chelating agent, decreased both VT and f, indicating involvement of
intracellular Ca2+ in the excitatory mechanisms of respiration. (4) 100-800 pmol
IBMX, an enhancer of intracellular cAMP, decreased both VT and f, indicating
involvement of cAMP in the inhibitory mechanisms of respiration. These results
indicate that the CO2/H+-sensitive neurons in the VMS contain glutamate and/or
GABA in cytoplasma, possess AMPA and/or GABA(A) receptors on surface of plasma
membrane, and compose the internal circuit, and that their activities are
regulated by Ca2+ and cAMP.
PMID- 9760078
TI - Efferent projection from the rostral ventrolateral medulla to the area postrema
in rats.
AB - The rostral ventrolateral medulla (RVLM) is a region of the brain primarily
involved in cardiovascular control. It receives information from several areas of
the brainstem, among which the area postrema (AP) and the nucleus of the solitary
tract (NTS). The medial subnuclei of the solitary tract (TS) project towards the
RVLM, providing cardiopulmonary information, and the AP serves information about
circulatory hormones. Although the efferent pathways are well known, it is not
the case for the connections from the RVLM towards the AP and the NTS. The
present study was designed to examine the efferent connections from the RVLM onto
the dorsal structures of the medulla: quantitatively by means of anatomical
techniques, and functionally by means of electrophysiological techniques.
Morphologically, Biocytin or Biotinylated dextran amine microinjections into the
RVLM were followed by labelling of many fibres running towards the bulbar
dorsomedial structures, with some pathways lying in the AP itself, or located in
its caudal vicinity. Conversely, when microinjections of Fast Blue (FB) were made
into the AP, FB-labelled cells could be observed within the RVLM.
Electrophysiologically, single shock stimulation carried on AP allowed
identification of axonal fibres issuing from somata located into the
cardiovascular neuronal pool in the RVLM. From these results, we can assume: (1)
the existence of dense efferent projection from RVLM to aspects of the dorsal
vagal complex, including the AP and, among this dense projection, (2) the
existence of some fibres terminating in, or crossing through the AP, and
identified as conveying baroreceptor-related information, in the rat.
PMID- 9760079
TI - Differential effects of anesthetics on sympathetic nerve activity and arterial
baroreceptor reflex in chronically instrumented rats.
AB - The effects of pentobarbital sodium, chloralose, and urethane on sympathetic
nerve activity and arterial baroreceptor reflex were examined using rats
chronically instrumented for recordings of blood pressure (BP), electrocardiogram
and renal sympathetic nerve activity (RSNA). Pentobarbital sodium (30 mg/kg,
i.v.) produced a decrease in BP with a transient decrease in heart rate (HR) and
no change in RSNA. Chloralose (50 mg/kg, i.v.) also caused a decrease in BP and
no change in HR and RSNA until a later increase in HR and RSNA, while urethane
(800 mg/kg, i.v.) increased BP, HR, and RSNA. Baroreceptor reflex function was
assessed by constructing a logistic function curve compiled from data obtained by
intravenous infusion in increasing doses of phenylephrine and sodium
nitroprusside. Both pentobarbital sodium and chloralose administration decreased
the gain of baroreceptor reflex control of both HR and RSNA. Urethane also
decreased the gain of baroreceptor reflex control of HR but elicited no change in
that of RSNA. These results suggest that different intravenously administered
anesthetics affect the peripheral sympathetic outflows in qualitatively and
quantitatively different manners.
PMID- 9760080
TI - Cholinergic vasoregulation in normal and adjuvant monoarthritic rat knee joints.
AB - The role of cholinergic nerves in joint vasomotor control was investigated in
normal and chronically inflamed rat knees. Joint inflammation was induced by
unilateral intraarticular injection of Freund's complete adjuvant and experiments
were performed on both the ipsilateral and contralateral joints one and three
weeks after treatment. Blood flow measurements of the exposed joints were
obtained using a laser Doppler perfusion imager which provides relative changes
in tissue perfusion. One week after adjuvant induction, basal perfusion in both
ipsilateral and contralateral joints was significantly reduced compared to
normal. At three weeks, ipsilateral knee perfusion had returned to normal,
however, contralateral blood flow showed no such sign of recovery. Topical
application of the muscarinic receptor antagonist atropine caused a fall in knee
joint basal perfusion suggesting that cholinergic nerves are inherently involved
in the physiological control of rat knee blood vessels. Acetylcholine chloride
(10(-13)-10(-8) mol) in normal rats produced a dose-dependent vasodilatation of
the articular microvasculature with the highest dose causing blood flow to
increase by about 85%. This dilator response was attenuated in the ipsilateral
monoarthritic joint at both one and three weeks post-injection while
contralateral joints showed a normal response to acetylcholine at both of the
time points tested. This study implicates cholinergic nerves in rat knee joint
vasoregulation, however, the impairment of this mechanism by chronic inflammation
could exacerbate the disease process by starving the joint of much needed
vascular nourishment. Furthermore, the preservation of cholinergic responses in
the contralateral knee despite a fall in basal perfusion suggests that
alternative non-cholinergic mechanisms may be responsible for the hypoaemia in
this joint.
PMID- 9760081
TI - Presynaptic muscarinic M1 and M2 receptor modulation of auriculotemporal nerve
transmission in the rat.
AB - Parotid secretory and vascular responses to electrical stimulation of the
parasympathetic innervation were measured in anaesthetized rats. Stimulation was
performed at 1, 10 and 40 Hz. Atropine (1.5 micromol/kg i.v.) almost abolished
the secretion to stimulation of peptide depleted nerves at 40 Hz, thus confirming
the existence of a pure cholinergic response. Atropine also reduced secretion by
74% during stimulation of non-depleted nerves at the same frequency. Selective
blockade by the muscarinic M1 receptor antagonist pirenzepine and by the
muscarinic M2 receptor antagonist methoctramine was found to occur at doses (50
nmol/kg i.v. and of 300 nmol/kg i.v., respectively) that did not inhibit the
responses to exogenous acetylcholine. In the presence of methoctramine, the nerve
evoked fluid responses were increased by 200% at 1 Hz independently of the total
number of impulses (10-300), suggesting that M2 receptor activation normally has
an inhibitory effect on transmitter release. The magnitude of the increase was
inversely related to frequency of stimulation, and changes in the secretory
responses occurred at 40 Hz only when non-depleted nerves were stimulated over
the longest period employed. The fluid response then increased by 35% and protein
concentration by 200%. The vasodilator responses increased at 1 and 10 Hz, but
not at 40 Hz. Pirenzepine reduced the secretory and vascular responses at 10 and
40 Hz but only during stimulation over short periods of time. This suggests that
M1 receptor activation normally has a facilitatory effect on neurotransmitter
release. During stimulation of non-depleted nerves at 10 Hz for 10 impulses, the
fluid response was reduced by 29% and the protein concentration by 26%. When the
peptide depleted nerves were stimulated at 10 Hz, pirenzepine also reduced the
fluid response (by 43%), but not the protein concentration. It is concluded that
the release of transmitter from postganglionic nerve fibres in the rat
auriculotemporal nerve is modulated by presynaptic muscarinic receptors.
Muscarinic M1 receptors normally facilitate cholinergic and peptidergic
transmission during short, intense stimulation. On the other hand, muscarinic M2
receptors normally inhibit cholinergic transmission at low frequencies; at higher
frequencies, peptidergic transmission is also inhibited, but only after some
delay.
PMID- 9760082
TI - Reexamination of custody restraint position and positional asphyxia.
AB - The use of the hogtie restraint (also known as hobble or prone maximal restraint)
by law enforcement and prehospital personnel has come under scrutiny because of
reports of sudden deaths in persons placed in this restraint position. Some
contend that this body position restricts chest and abdominal movement to the
point that individuals are at risk for hypoventilatory respiratory compromise and
"positional" asphyxiation. We review case reports of custody deaths in subjects
placed in the hogtie position, as well as related medical literature regarding
positional asphyxia. We also review the current research findings from human
physiology studies that have investigated the effects of the hogtie position on
respiratory and pulmonary function. We conclude that the hogtie restraint
position by itself does not cause respiratory compromise to the point of
asphyxiation and that other factors are responsible for the sudden deaths of
individuals placed in this position.
PMID- 9760083
TI - Vertebral artery trauma.
AB - Vertebral artery trauma is not commonly seen by forensic pathologists. The
experience of vertebral artery trauma at the Victorian Institute of Forensic
Medicine (30 cases) is summarized and reviewed in the light of the literature.
Causes of vertebral artery trauma are discussed. In case 1, the history and
timing of the injury raise the question as to whether the vertebral artery
dissection occurred before the episode of trauma, that is, was spontaneous or
resulted from trauma. Moreover, underlying vertebral artery disease was present,
raising the question as to how much trauma was needed to cause vertebral artery
dissection. In case 2, despite the history of head/neck trauma, a neurosurgeon
considered the subarachnoid hemorrhage was spontaneous, due most likely to
ruptured saccular aneurysm or arteriovenous malformation. In case 3, the
vertebral artery rupture was not diagnosed in the setting of multiple injuries.
Case 4 is an example of prolonged survival with delayed onset of symptoms
following vertebral artery trauma. Case 5 is an example of the not uncommon
scenario of homicidal vertebral artery trauma accounting for basal subarachnoid
hemorrhage, rapid collapse and death. Cases 1 and 4 indicate that relatively
normal activity may be possible following vertebral artery trauma in some cases
(at least for a time). Cases 1 and 4 are also examples of intracranial vertebral
artery dissection.
PMID- 9760084
TI - Air bag-associated injury to a child in the front passenger seat.
AB - We report the case of a 3.5-year-old front seat passenger who suffered
significant head and neck injuries as a result of air bag deployment in a
collision of <30 mph. These lesions included multiple abrasions of the lower half
of the face, nose, forehead, and right ear, torn frenula, conjunctival petechiae,
comminuted fractures of the left and right lateral frontal regions and right
parietal bone, diastatic fracture of the coronal suture, subgaleal and
subarachnoid hemorrhages, cortical contusions, subluxation of the
atlantooccipital joint, and fracture of the C4 vertebral body. These lesions are
consistent with trauma secondary to the deploying air bag and the head striking
the interior of the car. The findings in this case further support the Centers
for Disease Control and Prevention (CDC) guidelines of keeping children properly
restrained, preferably in the back seat, or as far as possible from air bags.
PMID- 9760085
TI - Problems in the interpretation of hemorrhage into neck musculature in cases of
drowning.
AB - To investigate the possible causes of unexplained hemorrhage into the neck
musculature in deaths due to drowning, all cases of drowning between the years
1985 and 1995 examined by members of the Department of Forensic Pathology,
University of Sheffield were reviewed. Cases were selected in which hemorrhage
was found within the neck musculature but in which no apparent explanation for
the hemorrhage, such as compression of the neck or trauma, was present. Eight
cases were identified from a total of 99 deaths from drowning. Postmortem
hypostasis was distributed in the back or diffusely in 6 cases and in the face in
3 cases. The degree of decomposition varied but was severe in only 1 case. A
raised blood alcohol level was detected in 3 cases. Anterior neck compartment
hemorrhage is probably due to hypostasis in a high proportion of cases. The
Prinsloo and Gordon artifact may be an operative factor in at least some cases.
Hemorrhage may result from violent neck movements during the process of drowning.
Apparent "bruising" of the neck musculature does not always indicate compression
of or trauma to the neck.
PMID- 9760086
TI - Injury patterns in a plastic (AR-1) baton fatality.
AB - Rubber and plastic bullets or batons have been used in countries outside the
United States for several years. These devices were designed to inflict nonlethal
force in riot control. The authors report a case of fatal injury sustained by an
elderly woman struck in the chest by a plastic baton, including the circumstances
surrounding this unusual incident, the autopsy findings and a review of the
literature.
PMID- 9760087
TI - A penny (or peso) for your thoughts: an unusual intermediate target.
AB - Intermediate targets becoming secondary projectiles in gunshot wounds is a well
recognized phenomenon. Secondary projectiles usually possess a fraction of the
kinetic energy compared to the primary projectile, leading to superficial wounds
of skin and soft tissue. We describe the case of a foreign object that was
propelled by the primary bullet with sufficient energy to penetrate not only skin
and soft tissue, but also temporal skull and brain. The report also examines the
energy requirements for an object to penetrate bone and unique radiographic
findings.
PMID- 9760088
TI - Toward an electronic death registration system in the United States: report of
the Steering Committee to Reengineer the Death Registration Process.
PMID- 9760089
TI - Forensic science program: a community effort.
AB - A forensic science program has been developed to assist the professional
community population in using a scientific approach in the investigation of
criminal offenses. The science of medicine and the principles of the law come
together to form a multidisciplinary group of professionals to instruct in the
collection of evidence after a crime has been committed. Specialists in these
areas include forensic pathologists, forensic anthropologists, forensic
odontologists, entomologists, and a radiologist with a specialty in forensics. No
longer can educators ignore the necessity of community involvement in the
apprehension and prosecution of the perpetrators of crime. This program is the
first to offer basic forensic science courses to professionals in a variety of
related fields.
PMID- 9760090
TI - The Abbreviated Injury Scale: application to autopsy data.
AB - Twenty autopsy reports, comprising 1 fall, 1 cutting, 1 burn, 1 drowning, 1
strangulation, 3 gunshot wound, and 13 traffic fatalities, were scored by the
Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS). The codes
were adequate for wounds of skin and long bones, and for most wounds of viscera.
The autopsy descriptions were more detailed than the coding criteria for
craniocerebral, cervicovertebral and muscular trauma, and less detailed for
thoracoabdominal visceral, and long bone trauma. Lung contusions and rib
fractures received scores that seemed unduly high, possibly reflecting the
greater sensitivity of autopsy diagnosis over clinical diagnosis for these
lesions. Complete hinge fractures of the skull base scored 4 (severe), which does
not reflect the almost universally lethal nature of the accompanying cerebral
concussion, which was itself not codeable. AIS scores were low and did not seem
to reflect the lethal outcome when the lethal mechanism was purely physiologic
and without a striking morphologic derangement, as in instances of cerebral or
cardiac concussion, compression of the neck, occlusive airway hemorrhage, and
visceral herniation into an adjacent body cavity. The scores were similarly low
when therapy was delayed or adverse. Low AIS and ISS scores in a fatality from
blunt or penetrating trauma may be useful retrospective clues to the presence of
purely physiologic death mechanisms or therapeutic problems.
PMID- 9760091
TI - Sudden death due to intravenous infusion of hair conditioner.
AB - A case of sudden death in a 14-year-old girl due to self administration of hair
conditioner through an intravenous infusion pump is described. This report
demonstrates difficulties that may occur in determining the manner of death in
such cases and outlines a specific danger that may occur when adolescents have
unsupervised access to intravenous infusion equipment.
PMID- 9760092
TI - Inadvertent intrathecal administration of potassium chloride during routine
spinal anesthesia: case report.
AB - During routine spinal anesthesia, an ampule of potassium chloride, instead of
bupivacaine, was mistakenly opened and inadvertently administered intrathecally
to a patient, resulting in pain, cramps, and death within 2.5 hours of injection.
We discuss the medicolegal implications of such an error and possible preventive
measures pertaining to this case.
PMID- 9760093
TI - Acute coronary artery thrombosis in a postpartum woman receiving bromocriptine.
AB - A 35-year-old postpartum woman who was receiving bromocriptine (Parlodel) for
only several days to suppress lactation experienced an episode of a seizure,
complained of chest pains, and died in the emergency department. At autopsy,
acute coronary thrombosis of the left main, left anterior descending, and
circumflex arteries was found. Cases of reported cardiac-related complications
associated with bromocriptine use in the puerperium are extremely rare. The
mechanism of bromocriptine-related acute coronary thrombosis is poorly understood
and warrants further scrutiny, because the synthetic brominated ergopeptide is
generally regarded as safe. The updated review of reports available in literature
mandates the acknowledgment of possible serious and even lethal cardiac events as
a result of untoward effects of bromocriptine.
PMID- 9760095
TI - Pericardial fluid postmortem: Comparative study of natural and violent deaths.
AB - Thanatochemistry is an increasingly important ancillary procedure in forensic
practice. Alterations are known to take place in biochemical components during
the postmortem period, particularly in the blood, and both research results and
their interpretation have been the object of some controversy. For that reason,
emphasis has been placed on the examination of fluids that are neither altered
nor contaminated as rapidly as blood after death. This study tested the
hypothesis that pericardial fluid (PF) may be a suitable medium for biochemical
analysis in corpses. The study sought to determine concentrations of urea,
creatinine, glucose, creatinine kinase 2, proteins, calcium, sodium, and
potassium, in the pericardial fluid of corpses. The study sample was divided into
two groups, natural deaths and violent deaths. Intergroup results were compared,
using Mann-Whitney's U test for paired data. No significant differences were
obtained between the natural death and violent death groups for the parameters
studied, with the exception of urea (p < .05). Further studies are required to
compare these results and create the possibility for new conclusions.
PMID- 9760094
TI - Amphetamine derivative fatalities in South Australia--is "Ecstasy" the culprit?
AB - OBJECTIVE: To analyze features of a series of fatalities caused by amphetamine
derivative designer drugs marketed as "Ecstasy" in South Australia, and to
identify reasons for the recent marked increase in number of these deaths.
MATERIALS AND METHODS: Following the death of a 26-year-old woman after alleged
ingestion of Ecstasy tablets, a retrospective search of files at State Forensic
Science, Adelaide and the South Australian State Coroner's Department was
undertaken from February 1992 to January 1997 to identify similar cases. RESULTS:
Six fatalities were found, all of which have occurred since September 1995 (M:F
ratio, 1:1; age range, 22 to 36 years; average age, 27.7 years). All individuals
had histories of recent ingestion of illegal drugs thought to be Ecstasy
(methylenedioxymethamphetamine, MDMA) at the time of purchase. Delay occurred in
seeking medical attention, despite severe symptoms. Causes of death involved
documented hyperthermia in 3 cases (temperatures of 41.5-46.1 degrees C), with
features of hyperthermia in one other case, and intracranial hemorrhage in
another. Drugs in toxic/lethal amounts identified at postmortem included
paramethoxyamphetamine (PMA) in all cases, amphetamine/methamphetamine in 4
cases, and methylenedioxymethamphetamine (MDMA or Ecstasy) in only 2 cases.
Interaction with a prescription medication (fluoxetine) may have occurred in 1
case. CONCLUSIONS: The number of deaths due to amphetamine derivatives apparently
due to substitution of PMA for MDMA (Ecstasy) have recently increased markedly in
Adelaide. Potential users should be warned that PMA has been associated with a
much higher rate of lethal complications than other designer drugs, and that no
guarantee can be made that tablets sold as Ecstasy are not PMA.
PMID- 9760096
TI - Automated coding of injuries from autopsy reports.
AB - Medical examiners have a unique database about trauma victims, many, if not most,
of whom died at the scene or in transit to a hospital and who, thus, never had
their injuries documented by trauma surgeons and so never entered into a local or
regional trauma registry. These trauma registries have assisted in assessing the
magnitude of traumatic injuries in the community and in evaluating the
community's emergency medical systems. Without information about those who are
dead at the scene or who die in transit, these trauma registries are incomplete
and the evaluations based on them inaccurate. The data about the 50% of trauma
victims who never enter the medical system are lacking in these registries. Such
information is present in the death investigation and autopsy reports in the
various medical examiner/coroner offices in the country. To access this important
information more easily in trauma registries, an expert computer system was
developed. This pilot study presents the results of using that system to gather
medical examiner data. Injury descriptions were abstracted from autopsy reports
of 50 consecutive nonhospitalized persons fatally injured in Mobile County,
Alabama and its environs. Injury descriptions for all cases were successfully
coded in International Classification of Disease, 9th Revision, Clinical
Modification (ICD-9-CM) and the Abbreviated Injury Scale (AIS-90) by an expert
system. For some cases the expert system "requested" and received clarifying
information, all of which was present in the medical records. This research
demonstrates the feasibility of gathering accurate and consistent information on
the estimated 50% of trauma deaths who do not reach a hospital and who are not
included in acute care registries. Without data on such patients, our evaluation
of trauma systems is incomplete and resources directed at prevention and
treatment may be misapplied.
PMID- 9760097
TI - Murder-suicide in central Virginia: a descriptive epidemiologic study and empiric
validation of the Hanzlick-Koponen typology.
AB - An empiric validation of a proposed typology of murder-suicide events was carried
out in the Central District of the Office of the Chief Medical Examiner of
Virginia for two cohorts, 1980 to 1984 and 1990 to 1994; use of a single typology
allows description of trends in these events over time, a unique aspect of this
study. For both cohorts, a total of 53 successful events with 63 victims (116
total deaths) was evaluated. A significant shift in the characteristics of
location, perpetrators, and victimology of such events between the two cohorts is
demonstrated: events changed from urban, multiple victim events with a majority
of white perpetrators to rural, dyadic events in which victims did not live with
perpetrators, the majority of whom were black. The results are compared with
published data, and the implications for use of this typology as a clinical
evaluation tool for prevention are addressed in light of current domestic
violence emphases in public health. Additionally, the need for prospective
tracking of these events is reiterated and use of the Hanzlick-Koponen typology
as the tool for such tracking is suggested.
PMID- 9760098
TI - Rate of aspartic acid racemization in bone.
AB - There are no reports on rates of amino acid racemization in bones. To investigate
the possibility of estimating age by evaluating amino acid residue racemization
in human bones, a heating experiment was performed and the rate of aspartic acid
racemization was determined using the Arrhenius equation. Assuming an annual mean
temperature of 15 degrees C, the rate constant (k) for aspartic acid racemization
in bone was calculated, and the racemization rate at 15 degrees C k (y) was
4.1036 x 10(-9)--much lower than that of dentin. These results suggest that it is
more difficult to accurately determine age by analyzing aspartic acid residues in
bone than in dentin.
PMID- 9760099
TI - The perfect crime: myth or reality?
AB - The primum movens of a forensic autopsy is to track down the crime. The perfect
crime can be defined as one which will never be suspected and/or one for which
the criminal will never be arrested. We have reported several cases that have
been adjudicated or are being adjudicated, and we show how actual homicides could
have been taken for accidental deaths, suicides, or even natural deaths.
PMID- 9760100
TI - Fatty liver in sudden infant death autopsies.
PMID- 9760101
TI - Homicidal poisoning by paraquat.
PMID- 9760102
TI - Nociceptin/orphanin FQ. A new opioid, a new analgesic?
AB - Opioids form the major class of strong analgesics. Endogenous opioids and their
receptors play important roles in central nervous system function. Thus, the
discovery of a new opioid peptide, nociceptin or orphanin FQ, and its receptor,
opioid receptor-like 1 (ORL-1) has caused considerable interest since this
transmitter system appears to exhibit a number of key differences to the other
opioids. Analgesia can be produced at spinal sites but there is compelling
evidence that the peptide may also have 'anti-opioid' actions in the brain.
Effects on auditory processing, pains from nerve injury coupled with an apparent
lack of motivational effects have important implications for novel therapy. This
review surveys the recent functional studies on this novel peptide.
PMID- 9760103
TI - Effect of 7-nitroindazole on body temperature and methamphetamine-induced
dopamine toxicity.
AB - The present study was undertaken to examine the role of temperature on the
ability of 7-nitroindazole (7-NI) to prevent methamphetamine-induced dopamine
(DA) neurotoxicity. Male Swiss-Webster mice received methamphetamine alone or in
combination with 7-NI at either room temperature (20+/-1 degrees C) or at 28+/-1
degrees C. At 20+/-1 degrees C, 7-NI produced hypothermic effects and afforded
total protection against methamphetamine-induced DA depletions in the striatum.
At 28+/-1 degrees C, 7-NI produced minimal effects on body temperature and failed
to prevent methamphetamine-induced DA reductions. These findings indicate that
the neuroprotection afforded by 7-NI is likely related to its ability to produce
hypothermia because agents that produce hypothermia and/or prevent hyperthermia
are known to attenuate methamphetamine-induced neurotoxicity.
PMID- 9760104
TI - Unspecific long-term potentiation can evoke functional segregation in a model of
area 17.
AB - It has been shown recently in rat hippocampus that the synapse specificity of
Hebbian long-term potentiation breaks down at short distances (< 100 microm).
Using a neural network model we show that this unspecific component of long-term
potentiation can be responsible for the robust formation and maintainance of
cortical organization during activity-driven development. When the model is
applied to the formation of orientation and ocular dominance in visual cortex,
addition of an unspecific component to standard Hebbian learning, in combination
with a tendency of left-eye and right-eye driven synapses to initially group
together on the postsynaptic neuron, induces the simultaneous emergence and
stabilization of ocular dominance and of segregated, oriented ON/OFF subfields.
Since standard Hebbian learning cannot account for the simultaneous stabilization
of both structures, unspecific LTP thus induces a qualitatively new behaviour.
Since unspecific LTP only acts between synapses which are locally clustered in
space, our results imply that details of the local grouping of synapses on the
dendritic arbors of postsynaptic cells can considerably influence the formation
of the cortical functional organization at the systems level.
PMID- 9760105
TI - Nociception activates Elk-1 and Sap1a following expression of the ORL1 receptor
in Chinese hamster ovary cells.
AB - Nociceptin stimulation of the ORL1 receptor expressed in Chinese hamster ovary
(CHO) cells results in the activation of the extracellular signal regulated
kinases ERK1 and ERK2. ERK1/ERK2 activation is inhibited by pertussis toxin, the
MEK inhibitor PD 98059 and by transient expression of alpha-transducin,
indicating that ORL1 up-regulation of these kinases occurs as a consequence of
the release of the G-protein betagamma complex following the activation of
pertussis-toxin sensitive Galphai-family G-proteins. Using specific reporter
genes we demonstrate that the transcription factors Elk-1 and Sapla are activated
in a pertussis toxin-sensitive manner as a consequence of ORL1 upregulation of
ERK1/ERK2 to induce changes in gene expression. The activation of these
transcription factors is also inhibited following treatment with PD 98059 and
following coexpression of alpha-transducin.
PMID- 9760106
TI - Mismatch negativity (MMN) as an index of auditory sensory memory deficit in cleft
palate and CATCH syndrome children.
AB - Our recent study demonstrated with the brain's automatic change-detection
response, the mismatch negativity (MMN) of the event-related potentials (ERPs),
that the duration of auditory sensory memory is significantly shorter in school
age children with CATCH syndrome than in healthy age-matched controls. One of the
characteristic symptoms of this syndrome, caused by a microdelection in
chromosome 22, is cleft palate. The most common problems in these children,
however, are learning difficulties and, according to our results, it is likely
that these problems are not due to the dysmorphology of peripheral speech
mechanisms only but are also caused by CNS dysfunctions. In the present study we
show with MMN that auditory sensory memory is also shortened in school-age
children with cleft palate but without the CATCH syndrome. It has been shown in
previous studies with neuropsychological tests that although children with cleft
palate have language and learning-related problems these difficulties are usually
less severe than those of CATCH children. Likewise the present study demonstrates
that the auditory sensory memory trace seems to decay more rapidly in CATCH
children than in children with cleft palate.
PMID- 9760108
TI - Abnormal mushroom body plasticity in the Drosophila memory mutant amnesiac.
AB - In Drosophila melanogaster, adult or larval rearing conditions influence brain
structure. In particular, larval density affects the number of fibers forming the
mushroom bodies, a neuropil structure involved in olfactory learning. The
mushroom bodies receive chemosensory inputs from the antennal lobes at the level
of the calyx. In this study we report that larval density affects calyx volume
measured shortly after eclosion from the pupal case. We observe that in the
memory mutant amnesiac this form of experience-dependent structural plasticity is
missing, whereas it is not affected in the learning mutant rutabaga and in the
memory mutant radish. Independent of the plasticity effect, the calyces are on
average slightly bigger than wild type in amnesiac and smaller in rutabaga flies.
PMID- 9760107
TI - NPY Y1 receptors in the dorsal periaqueductal gray matter regulate anxiety in the
social interaction test.
AB - We have reported previously that the NPY Y1 receptor antagonist BIBP3226 applied
into the dorsal periaqueductal gray matter (DPAG) has an anxiogenic-like effect
in the elevated plus-maze test in rats. In the present study the effects of
neuropeptide Y (NPY) Y1 receptor antagonists BIBP3226 (500 pmol) and 1229U91
(formerly also GR231118, GW1229 and EXBP68, 100 and 500 pmol) administered into
the DPAG were investigated in the social interaction test in rats. BIBP3226 and
1229U91 (both 500 pmol) significantly decreased the time spent in active social
interaction. These results provide additional evidence that NPY-ergic
neurotransmission in the DPAG may be involved in the modulation of anxiety
related behaviour and suggest that endogenous NPY, released under stressful
conditions in the DPAG, relieves anxiety via the NPY Y1 receptors. This is the
first report demonstrating the effect of NPY receptor active agent on social
behaviour.
PMID- 9760109
TI - Failure of localized head cooling to reduce brain temperature in adult humans.
AB - Non-invasive brain temperature measurements using proton magnetic resonance
spectroscopy were used to test the hypothesis that localized head cooling would
reduce brain temperature in 10 normal adult humans. Temperature reductions of the
head surface to 15.8+/-3.5 degrees C did not reduce brain temperature measured in
the superficial cortex (36.8+/-0.5 degrees C) or thalamus (36.6+/-0.7 degrees C),
as compared to measurements obtained with a head surface temperature of 34.7+/
1.6 degrees C (37.0+/-0.6 degrees C and 36.6+/-0.4 degrees C, respectively).
There was no change in the temperature gradient from the superficial to deep
brain locations in the presence or absence of head cooling, and brain temperature
did not decrease as a function of the duration of head cooling for periods up to
50 min. There was no correlation between the scalp surface (range: 10-38 degrees
C) and brain temperature at either the deep or superficial locations.
PMID- 9760110
TI - Kv1.1 channel antisense attenuates learning and modulation of dentate
polysialylated NCAM.
AB - The distribution and modulation of neural cell adhesion molecule polysialylation
state (NCAM PSA) and the consequence of antisense inactivation of the Kv1.1
potassium channel was investigated following avoidance learning in mice. PSA
immunoreactivity was most notable on cells at the inner denate border and in
cortical layer II. Task acquisition resulted in a significant 30% transient
increase in the frequency of dentate polysialylated neurons at the 12 h post
training time. In contrast, animals pretreated with the Kv1.1 antisense
oligonucleotide exhibited both attenuated recall avoidance latencies and
polysialylated cell frequency. As Kv1.1 is enriched on the dendrites of these
granule-like cells, the attenuated polysialylation response is considered
secondary to NCAM-mediated events during their transient synapse production in
the 6-8 h post-training period.
PMID- 9760111
TI - Attenuation of c-Fos basal expression in the cerebral cortex of aged rat.
AB - Cellular immediate early genes (IEG) such as c-fos were originally defined as
rapid and transient inducible gene, but their products show a varying degree of
basal expression in the brain of normal animals, suggesting that they also play a
role in the transcriptional control under physiological conditions. In this
study, we used an immunohistochemical method to investigate changes in the number
of c-Fos-immunoreactive cells in the cerebral cortex and hippocampal formation of
the aged rat. There was a remarkable decrease in the number of c-Fos
immunoreactive cells in the piriform and temporal cortex of aged rats compared
with young adult rats. There was a slight decrease in the number of c-Fos
immunoreactive cells in the parietal cortex of aged rat. In the hippocampal
complex, there were also decreases in the number of c-Fos-immunoreactive cells in
aged rat; the degree of decrease was most prominent in the dentate gyrus. This
report provides the first morphological evidence for decreased levels of basal c
Fos expression in some cerebral cortical areas and in the hippocampal complex of
aged rats.
PMID- 9760112
TI - Presynaptic modulation of Lymnaea neurons evoked by computer-generated spike
trains.
AB - To investigate the functional organisation and information processing in Lymnaea
neuronal networks, artificial spike trains were elicited in one of the main
respiratory interneurons (RPeD1) and the modulation of the firing patterns of
postsynaptic cells was examined. This was performed by precisely timing the
action potential generation of the presynaptic cell using a computer-controlled
voltage clamp amplifier (pattern clamp technique). Induced oscillation (0.1-0.4
Hz) in the firing pattern of RPeD1 spread to a large number of postsynaptic
cells, as clearly demonstrated by Fourier power spectra. At the same time, no
signs of precise (millisecond) spike timing was observed in the cells studied.
The results confirm that the neurons used in our experiments process information
as pure rate-coders.
PMID- 9760113
TI - Partial cloning and distribution of estrogen receptor beta in the avian brain.
AB - A partial estrogen receptor beta (ER-beta) cDNA was isolated from testicular
quail RNA by RT-PCR with degenerate primers specific to the rat ER-beta sequence.
A high expression of ER-beta was demonstrated by RT-PCR in the telencephalon,
diencephalon, pituitary, testis and kidneys of male quail but little or no
expression was detected in the cerebellum, pectoral muscle and adrenal gland. In
situ hybridization with a 35S-labelled oligoprobe in sections through the
preoptic area-rostral hypothalamus identified high expression in the medial
preoptic nucleus, bed nucleus striae terminalis and nucleus taeniae. These data
demonstrate the presence of an ER-beta in brain areas implicated in the control
of reproduction in a non-mammalian species.
PMID- 9760114
TI - Immunohistochemical localization of redox factor-1 (Ref-1) in Alzheimer's
hippocampus.
AB - Redox factor-1 (Ref-1) is a dual-function protein involved in both DNA repair and
transcriptional regulation. Ref-1 is modulated by cerebral ischemia and other
oxidative stressors, and also regulates the DNA-binding activities of
transcription factors implicated in Alzheimer's disease (AD)-related
neurodegeneration. The present study examined Ref-1 expression in the AD
hippocampus by immunohistochemistry. Although Ref-1 immunostaining was relatively
low in control brain sections, senile plaques and other plaque-like structures in
the AD brain were Ref-1-positive. Cells with increased Ref-1 immunoreactivity
were also observed in regions of neuronal injury. These results suggest that Ref
1 might contribute to senile plaque formation, and that overexpression of Ref-1
in injured neurons may be part of a response to oxidative stress and an attempt
to repair damaged DNA in AD.
PMID- 9760115
TI - Alpha and beta subunits of CaM-kinase II are localized in different neurons in
chick ciliary ganglion.
AB - The ciliary ganglion of the chicken contains only two types of neurons. Using
monoclonal antibodies against the alpha and the beta subunits of Ca2+/calmodulin
stimulated protein kinase II (CaMPK-II) we found that the alpha-subunit was
localized to the choroid neurons while beta subunit was associated with the
ciliary neurons. As both neurons receive their inputs from the oculomotor nerve,
while their postganglionic axons leave via different nerves, the ciliary ganglion
of the chicken is a neuronal system in which the functional differences between
alpha and beta CaMPK-II homopolymers in the regulation of synaptic transmission
can be investigated.
PMID- 9760116
TI - Multiple classes of the oligodendrocyte lineage are highly vulnerable to
excitotoxicity.
AB - We have recently shown that galactocerebroside (Gal-C)-expressing
oligodendrocytes are highly vulnerable to (AMPA)/kainate receptor-mediated death.
Here we examined the vulnerability of cells at different developmental stages of
the oligodendrocyte lineage to AMPA/kainate receptor-mediated excitotoxicity.
Oligodendrocyte precursor cells, pre-oligodendrocytes and mature oligodendrocytes
were killed by 24 h exposures to low concentrations of kainate (30-100 microM).
Death was attenuated by the AMPA/kainate receptor antagonist 6-nitro-7
sulfamoylbenzo(f)quinoxaline-2,3-dione (NBQX). The high vulnerability of
oligodendrocytes and their precursors to AMPA/kainate receptor excitotoxicity may
represent an important mechanism of white matter damage resulting from trauma or
ischemia in the perinatal and adult central nervous system (CNS).
PMID- 9760117
TI - CCK-8 inhibits ingestive behavior in rats with lateral hypothalamic 6-OHDA
lesions.
AB - Male rats were injected with 6-hydroxydopamine in the lateral hypothalamus and
tested for ingestive behavior starting on the day after the injection. The rats
did not eat food pellets but readily ingested an intraorally infused nutritive
solution. If given three daily intraoral infusions, 6-hydroxydopamine-treated
rats defended their body weight and were as sensitive to the inhibitory effect of
cholecystokinin octapeptide on intake as controls. Dopamine was reduced by 94% in
the dorsal striatum five days after the 6-hydroxydopamine injection.
Noradrenaline and serotonin were less markedly affected. Thus, while appetitive
ingestive behavior is disrupted, consummatory ingestive behavior and body weight
regulatory competence are only marginally affected by massive damage to forebrain
dopamine neural networks.
PMID- 9760118
TI - Purification of bovine P2 myelin protein with bound lipids.
AB - The P2 protein is a neuritogenic, small basic protein present in PNS myelin. It
belongs to the family of the cytoplasmic lipid-binding proteins and can be
incorporated in lipidic bilayers. P2 has been purified and crystallized only in
the lipid-free form. Here we show that the P2 protein can be purified with bound
lipids by applying to PNS myelin the same procedure that as used to purify lipid
bound myelin basic protein from CNS myelin. SDS-PAGE showed a single band of 16.5
kDa, and TLC showed the presence of most of the myelin lipids associated with the
protein. Lipid-bound P2 revealed different circular dichroism spectra from the
corresponding lipid-free form, indicating that lipids influence P2 conformation.
PMID- 9760119
TI - Rapid actions of insulin on sensory nerve function.
AB - The acute action of insulin on neurogenic flare was investigated using
iontophoresis. Twenty-five patients with insulin-dependent diabetes mellitus
(IDDM) and 25 age- and gender-matched controls were studied. Axon reflex
vasodilatation was evoked by transdermal iontophoresis of acetylcholine (ACh)
before and after skin treatment by the iontophoresis of insulin and measured
using laser Doppler velocimetry. Axon reflex responses were reduced in IDDM
patients compared with controls (p< 0.001) but were restored after the
iontophoresis of insulin. Insulin iontophoresis had no effect on the size of the
axon reflex response in control subjects (p > 0.05). This study confirms the
reduction of the ACh-induced flare in human patients with IDDM and has
demonstrated relatively rapid effects of insulin on this cutaneous neurogenic
response.
PMID- 9760121
TI - Development of glycinergic transmission in organotypic cultures from auditory
brain stem.
AB - We investigated whether glycinergic transmission develops organotypically in
auditory brain stem cultures. Slices of the medial nucleus of the trapezoid body
and the lateral superior olive were incubated in medium with a raised
extracellular K+ concentration. As in vivo, glycine receptor alpha1 subunit
immunoreactivity increased and became clustered on somata and proximal dendrites.
Together with organotypic expression of glycine transporter GLYT2, this indicates
that molecular components of glycinergic synapses form properly. In contrast,
glycinergic synaptic currents did not develop as in vivo: after 7 days in vitro
they were still similar to those at the time of culture preparation. We suggest
that for organotypic development of glycine receptors and transporters, Ca2+
influx due to elevated K+ is sufficient. The development of functional synaptic
transmission, however, may require patterned electrical activity.
PMID- 9760120
TI - Secondary inhibition of 2-ketoglutarate dehydrogenase complex by MPTP.
AB - The parkinsonism-inducing neurotoxin 1-methyl-4-phenylpyridine (MPP+) acts
through inhibition of complex I of the electron transport chain. Recent evidence
suggests that it may also act through inhibition of 2-ketoglutarate dehydrogenase
complex (KDHC). We confirmed this observation in isolated rat liver mitochondria
but found that this inhibition is prevented by preincubation with the radical
quencher, cysteine (Cys). KDHC is also inhibited by the NO generator S-nitroso-N
acetyl-penicillamine (SNAP) and this inhibition is similarly blocked by cysteine.
MPP+ may inhibit KDHC secondary through a radical-mediated event rather than
through direct interaction with KDHC.
PMID- 9760122
TI - Tissue-type plasminogen activator is not required for kainate-induced motoneuron
death in vitro.
AB - Spinal motoneurons are highly vulnerable to kainate both in vivo and in vitro.
Tissue-type plasminogen activator (tPA) and plasmin have recently been shown to
mediate kainate-induced neuronal death in the mouse hippocampus in vivo. The aim
of the present study was to determine whether tPA also mediates the kainate
induced death of motoneurons in vitro. A motoneuron-enriched neuronal population
was isolated from the ventral spinal cord of wild-type (WT) and tPA-deficient
(tPA-/-) mouse embryos. WT and tPA-/- neurons were cultured on WT and tPA-/-
spinal glial feeder layers, respectively. WT and tPA-/- co-cultures were
morphologically indistinguishable. Expression of tPA in WT co-cultures was
demonstrated using RT-PCR. WT and tPA-/- co-cultures were exposed to kainate for
24 h. The neurotoxic effect of kainate did not differ significantly between WT
and tPA-/- cultures. The plasmin inhibitor alpha2-antiplasmin did not protect WT
neurons against kainate-induced injury. These results indicate that the plasmin
system is not a universal mediator of kainate-induced excitotoxicity.
PMID- 9760123
TI - Widespread programmed cell death in early developing chick optic tectum.
AB - We demonstrate that widespread programmed cell death exists in proliferative
regions of chicken optic tectum during early development using a sensitive
fluorescent ISEL method (FISEL+) and antibody staining for an antigen in dying
cells. Several developmental stages from embryonic day (E) 3 to E18 were
examined. FISEL+-positive cells were rare before E7 and between E9 to E12.
However, massive labeling was observed in the ventricular zone (VZ) between
stages E7.5 and E8. At this time extensive cell migration is underway and many
labeled cells were found not only in the VZ (premigratory cells) but also in the
intermediate zone and tectal plate (migratory cells). Many labeled cells were
also found in upper tectal laminae at late developmental stages (E15 and E18).
PMID- 9760124
TI - Sex differences in brain regions activated by grammatical and reading tasks.
AB - Do the brains of men and women show similar patterns of functional organization
for language, or are men more strongly lateralized? We used PET to measure
cerebral blood flow (CBF) as men and women read real and nonce verbs, and
produced past tense forms. While the overall patterns of reaction time, error,
and brain activation were similar, there were also significant sex-related
differences in CBF patterns. During the past tense generation tasks, men showed
left-lateralized activation while women recruited bilateral perisylvian cortex,
confirming differences in functional laterality. During all tasks, women showed
higher activation in occipital and/or cerebellar regions, suggesting differences
in basic reading strategies. We conclude that sex differences in functional
cortical organization exist in the absence of significant behavioral differences.
PMID- 9760125
TI - Infusion of GDNF into the cerebral spinal fluid through two different routes:
effects on body weight and corticospinal neuron survival.
AB - Survival of axotomized adult rat corticospinal neurons (CSN) is supported by
glial cell line-derived neurotrophic factor (GDNF). We have evaluated the trophic
effects of intrathecally applied GDNF on CSN survival and rat body weight. Body
weight reduction is the major side effect of intracerebral neurotrophic factor
treatment. GDNF was tested at total doses of 30, 100 and 300 microg over 7 days
after axotomy via different application routes: intracerebroventricularly
(i.c.v.) and cisternally (cis). Animals injected i.c.v. displayed severe body
weight reduction at all doses tested but CSN rescue only at the highest dose. In
contrast, cis-infusion of GDNF promoted CSN survival at all doses and only the
highest dose reduced the body weight. These results show that intracisternal, but
not i.c.v., GDNF infusion at low doses can promote CSN survival without
negatively affecting rat body weight. This finding may have implications for the
clinic use of GDNF.
PMID- 9760126
TI - Lazaroid-enhanced survival of grafted dopamine neurons does not increase target
innervation.
AB - The lazaroid U-74006F enhances survival of grafted ventral mesencephalic neurons.
In this study the intraocular grafting model was used and survival and outgrowth
from fetal ventral mesencephalic grafts treated with U-74006F was evaluated in
nigrostriatal co-grafts. Fetal lateral ganglionic eminence was implanted into the
anterior eye chamber and left to mature. Fetal ventral mesencephalon was then
implanted and the eyes were treated with U-74006F. The lazaroid treatment
enhanced survival of tyrosine hydroxylase (TH)-positive neurons, but did not
enhance TH-positive nerve fiber growth into the striatal portions of the co
grafts. However, a marked increase in nerve fiber formation was found within the
ventral mesencephalic grafts. In conclusion, increased cell survival enhanced
nerve fiber formation within the ventral mesencephalic portion of the co-graft
and not, as expected, in the striatal part.
PMID- 9760127
TI - Neuropathological findings after intracerebral implantation of microdialysis
catheters.
AB - The neuropathological and immunocytochemical changes in the sheep forebrain
following 7 days of microdialysis, using a catheter approved for human use, are
described. There was no behavioural dysfunction and light microscopy revealed
mild astrogliosis and patchy macrophage infiltration immediately adjacent to the
catheter track. The surrounding neuropil was normal. There was one small
subcortical haemorrhage (10 x 1.5 mm). These findings are similar to those
following microdialysis in rodents and suggest that the risk of significant
damage to the human brain is low, that neuropathological changes in the brain
around the catheter should not interfere with local brain metabolism, and that
the catheter should be affixed in such a way as to minimize movement-induced
damage to the brain.
PMID- 9760128
TI - Prosaptide prevents hyperalgesia and reduces peripheral TNFR1 expression
following TNF-alpha nerve injection.
AB - This study demonstrated that hyperalgesia resulting from an intraneural injection
of the cytokine tumor necrosis factor-alpha (TNF) was prevented by preemptive
administration of a single dose of the prosaptide TX14(A) (200 microg/kg).
TX14(A) is a synthetic 14-mer peptide with neurotrophic and cytoprotective
activities. Efforts to elucidate TX14(A) antagonism of hyperalgesia concentrated
on determining the effect of TX14(A) on the up-regulation of the 55 kDa TNF
receptor (TNFR1) at the nerve injury site. It has been previously shown that
TNFR1 expression is upregulated following nerve injury and parallels the display
of nociceptive behavior. In our experiments, TNFR1 was decreased at the TNF nerve
injection site in TX14(A)-treated rats when compared to vehicle-treated or
control peptide-treated rats. Light microscopic evaluation of nerve injury site
tissue displayed qualitatively similar neuropathology in both treatment groups
during the time of peak hyperalgesia (day 3), but appeared more normal than
untreated nerves at day 7 (histological scoring, mean +/-s.d., 3.7+/-0.57 for
TX14(A)-treated and 5.67+/-0.5 for control peptide-treated). These results
suggest that TX14(A) decreased nociceptive behavior by attenuating both TNFR1
upregulation and Schwann cell activation in response to TNF injection. This
prosaptide neurotrophin may also moderate nerve degeneration or promote
regeneration. It is not known whether TX14(A) also acts rostral to the lesion
site.
PMID- 9760129
TI - Pituitary adenylate cyclase-activating peptide is upregulated in sensory neurons
by inflammation.
AB - The neuropeptide pituitary adenylate cyclase-activating peptide (PACAP) is
expressed in sensory neurons. Expression of several neuropeptides is up-regulated
in sensory neurons following inflammation. To examine whether also PACAP
expression is regulated by inflammation, PACAP expression in L5 dorsal root
ganglion (DRG) was determined, using in situ hybridization, after unilateral
adjuvant-induced inflammation in the rat paw. At 12 h and day 3, but not day 21,
the percentage of neurons expressing PACAP mRNA was greater in the innervating L5
DRG. Similarly, PACAP mRNA expression in individual neurons was higher in the
innervating L5 DRG at 12 h and day 3, but not day 21. Up-regulated PACAP
expression following adjuvant injection suggests a role for PACAP in
inflammation.
PMID- 9760130
TI - Viability and survival of hNT neurons determine degree of functional recovery in
grafted ischemic rats.
AB - We recently reported behavioral improvements following intrastriatal
transplantation of cryopreserved cultured human neuroteratocarcinoma-derived
cells (hNT neurons) in rats with cerebral ischemia induced by occlusion of the
middle cerebral artery. In the present study, the viability and survival of hNT
neurons were evaluated immediately prior to the transplantation surgery and at 3
months post-transplantation in ischemic rats. Cryopreserved hNT neurons were
routinely thawed, and trypan blue exclusion viability counts revealed 52-95%
viable hNT neurons before transplantation. Monthly behavioral tests, starting at
1 month and extending to 3 months post-transplantation, revealed that ischemic
animals that were intrastriatally transplanted with hNT neurons (approximately
40000) and treated with an immunosuppressive drug displayed normalization of
asymmetrical motor behavior compared with ischemic animals that received medium
alone. Within-subject comparisons of cell viability and subsequent behavioral
changes revealed that a high cell viability just prior to transplantation surgery
correlated highly with a robust and sustained functional improvement in the
transplant recipient. Furthermore, histological analysis of grafted brains
revealed a positive correlation between number of surviving hNT neurons and
degree of functional recovery. In concert with similar reports on fetal tissue
transplantation, we conclude that high cell viability is an important criterion
for successful transplantation of cryopreserved neurons derived from cell lines
to enhance graft-induced functional effects.
PMID- 9760131
TI - Immunolocalization of leukemia inhibitory factor in normal and denervated human
muscle.
AB - The cytokine leukemia inhibitory factor (LIF) stimulates myoblast proliferation
in vitro and vivo and is neurotrophic for motor neurons. In experimentally
reinnervated muscle, exogenous LIF application increases muscle mass through
myofiber hypertrophy. The goal of this study was to evaluate possible sources of
endogenous LIF in human muscle, and whether LIF immunoreactivity (-IR) was
detectable in specific myofiber types and/or re-expressed in human denervated
muscle. Our study shows that LIF-IR is constitutively detectable in type I
myofibers of normal human muscle. In acute and chronically denervated and
reinnervated human muscle, LIF-IR is found in all type I myofibers and in
addition in some atrophic and almost all angulated atrophic type II myofibers.
PMID- 9760132
TI - Medial nigral dopamine neurons have rich neurotrophin support in humans.
AB - To assess the action of neurotrophin in human dopaminergic neurons, we studied
the immunolocalization of neurotrophins or trks in human substantia nigra pars
compacta (SNc). The neuromelanin-containing neurons in the SNc showed
immunoreactivities for neurotrophins or trks, suggesting an autocrine/paracrine
regulation. Quantitative analysis revealed that the percentage of those
expressing NGF-like immunoreactivity (NGF-LI), BDNF-LI, NT3-LI, trkA-LI, trkB-LI,
or trkC-LI was 66%, 74%, 85%, 66%, 71% or 86%, respectively. The percentage of
cells expressing neurotrophins or trks was higher in the medial part than in the
lateral part of the SNc. The preferential expression of neurotrophin-trk systems
in the medial neurons may, at least partially, explain the differential
susceptibility in Parkinson's disease.
PMID- 9760133
TI - Sleep deprivation induces brain region-specific decreases in glutathione levels.
AB - Rats were deprived of sleep for 96 h by the platform technique and total
glutathione (GSHtau) levels were measured in seven different brain areas.
Glutathione levels were found to be significantly reduced in the hypothalamus of
sleep-deprived animals when compared with large platform (-18%) or home cage (
31%) controls. Deprived rats also had reduced GSHtau levels in thalamus compared
with home cage controls only. Glutathione levels did not differ among the three
groups in any of the other brain areas examined. These results indicate that
specific brain areas may be differentially susceptible to oxidative stress after
sleep deprivation. The apparent vulnerability of the hypothalamus to these
effects may contribute to some of the functional effects of sleep deprivation.
PMID- 9760135
TI - Distribution of catechol-O-methyltransferase expression in human central nervous
system.
AB - Catechol-O-methyltransferase (COMT, EC 2.1.1.6) is a ubiquitous enzyme crucial to
catechol metabolism. Two isoforms exist in the human central nervous system (CNS)
and they are encoded by two transcripts (1.3 and 1.5 kb) in most human tissues.
Using two alpha-32P-labeled probes, we found only the 1.5 kb transcript in all 16
regions of the human CNS using commercially available Northern blots. Spinal cord
had the highest and amygdala had the lowest levels of expression. The other CNS
regions shared a similar level of expression. The distributions of COMT gene
expression relative to whole brain between both probes were significantly
correlated. Our study shows that the expression of the 1.5kb transcript is
crucial for COMT activity in all regions of the human CNS.
PMID- 9760134
TI - Adenosine A2A receptors modify motor function in MPTP-treated common marmosets.
AB - Both adenosine A1 and A2 receptor populations are located in the striatum and can
modify locomotor activity, and they may form a therapeutic target for Parkinson's
disease (PD). Administration of the selective adenosine A2A antagonist (E)-1,3
diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-pu rine-2,6-dione (KW
6002) to MPTP-treated common marmosets increased locomotor activity. In contrast,
administration of the selective A1 receptor antagonist 1,3-dipropyl-8
cyclopentylxantine (DPCPX) had no effect on locomotion. Administration of the
adenosine A2A receptor agonist 2-[p-[2-(2-aminoethylamino) carbonylethyl]
phenethyl amino]-5'-N-ethylcarboxamidoadenosine (APEC) dose dependently
suppressed basal locomotor activity. A minimally effective dose of APEC (0.62
mg/kg, i.p) completely reversed the increase in locomotor activity produced by
administration of KW-6002. The adenosine A2A receptor appears to be an important
target for the treatment of basal ganglia disorders, particularly PD.
PMID- 9760136
TI - Proprioception acts as the main source of input in human S-I activation
experiments: a functional MRI study.
AB - During tactile exploration cells in human somatosensory cortex S-I receive input
from skin receptors and from proprioceptive feedback. To study the extent to
which these sources contribute to cell activation we used functional magnetic
resonance imaging (fMRI) in order to visualize the spatial extent and amplitude
of activation in S-I during active finger movement and passive stimulation of
finger tips. In all subjects (n = 6) we measured activation elicited by
unilateral single finger tapping (active task) and mechanical stimulation of the
palm of the index finger (passive task). In the finger tapping condition all
subjects showed a strict contralateral activation of somatosensory cortex S-I and
motor cortex M-I. In the passive stimulation experiment we found activation of
the contralateral somatosensory cortex S-I only. Although subjects were trained
to perform the finger movement with the same frequency and pressure in comparison
to the passive stimulation, the activation within S-I induced by finger movements
was always significantly larger than that induced by passive stimulation. This
result implies that activation of somatosensory cortex originates to a large
extent from proprioception while tactile input plays a minor role in S-I
excitation.
PMID- 9760137
TI - Stat3 and NFkappaB glial expression after excitotoxic damage to the postnatal
brain.
AB - The nuclear factor-kappa B (NFkappaB) and the signal transducer activator of
transcription 3 (STAT3), are putative transcription factors activated by growth
factors and cytokines, and involved in glial gene expression changes after
neuronal injury. Immunocytochemical analysis of NFkappaB and STAT3 from 2 h to 14
days after excitotoxic damage to the postnatal rat brain showed STAT3- and
NFkappaB-positive glial cells at 2 h post-lesion, increasing in number to reach a
maximum at day 1. Immunoreactivity then decreased but the glial scar remained
positive. Glial STAT3 immunoreactivity was located in the nucleus up to 1 day
post-lesion and in the nucleus, cytoplasm and cell processes from day 3. Glial
NFkappaB immunoreactivity was mainly cytoplasmatic.
PMID- 9760138
TI - Strong synergism between GABA(A) and glycine receptors on isolated carp third
order neurons.
AB - A strong synergistic interaction between the bicuculline-sensitive GABA receptor
(GABA(A) receptor) and the strychnine-sensitive glycine receptor was observed in
third-order neurons acutely isolated from crucian carp retina, with the use of
the whole-cell patch-clamp recording technique. In 58 of 153 cells, 10 microM
GABA or glycine separately applied to amacrine/ganglion cells failed to induce
any responses or only induced small currents (<20 pA), while co-application of
these two chemicals resulted in much larger responses (403.05+/-319.98 pA). The
current induced by the co-application was mediated by chloride channels, and both
GABA(A) and glycine receptors were involved in the potentiation. The underlying
mechanisms of this interaction and its possible physiological role are discussed.
PMID- 9760139
TI - 3-Nitropropionic acid-induced changes in the expression of metabolic and
astrocyte mRNAs.
AB - Systemic administration of 3-nitropropionic acid (3NPA) in rats produces
bilateral striatal lesions which are similar to those seen in Huntington's
disease (HD). We examined the effects of systemic 3NPA on the expression of
cytochrome oxidase (COX-II and COX-IV), succinate dehydrogenase (SDH) and
astrocytic glial fibrillary acidic protein (GFAP) mRNAs and on the activity of
COX and SDH as assessed by the density of histochemical staining. COX-II and COX
IV mRNA was reduced in rats with 3NPA-induced lesions, but not in those without,
whereas SDH, but not COX, staining was significantly and dose-dependently reduced
in both 3NPA treated groups. GFAP mRNA expression was increased in both intact
striatum and cortex but was absent from the lesion core.
PMID- 9760140
TI - Pre-exposure to alcohol does not sensitize to the rewarding effects of cocaine.
AB - The conditioned place preference (CPP) induced by cocaine 2.5 mg/kg was measured
in rats pre-exposed to ethanol (14 days with only 10% v/v ethanol followed by a
free choice between ethanol solution and water for 14 days). Rats were divided
according to their alcohol intake during the free choice period into low-drinking
(<3 g/kg per day), intermediate-drinking and high-drinking (> 4 g/kg per day)
rats. Cocaine-induced CPP was not modified in high-drinking rats relative to
controls. Low-drinking rats had a lower CPP than high-drinking rats and controls.
We conclude that pre-exposure to alcohol did not sensitize to the cocaine
rewarding effects, and that alcohol low-drinking rats showed the lowest
preference for cocaine.
PMID- 9760141
TI - Immunocytochemical localization of GDNF in primary afferents of the lumbar dorsal
horn.
AB - Immunocytochemistry was used to identify glial cell line-derived neurotrophic
factor (GDNF) in rat spinal cord. Strong GDNF labeling was found in fibers and
terminals in laminae I and II (outer) and to a lesser extent in the remaining
laminae. A few spinal ganglion cells also contained GDNF. After dorsal root
transection GDNF disappeared from the dorsal horn and after dorsal root ligation
there was accumulation of GDNF only on the ganglion side of the ligation. These
findings demonstrate anterograde transport of GDNF within primary afferent
fibers, which constitute the only source of GDNF labeling in the dorsal horn. The
strong presence of GDNF in the superficial dorsal horn may indicate that GDNF has
a role in pain transmission in the adult rat spinal cord.
PMID- 9760142
TI - Transitory expression of NADPH diaphorase (NOS) in axonal swellings after spinal
cord injury.
AB - To investigate the sites of nitric oxide synthase (NOS) expression after a spinal
cord (SC) injury, NADPH-d diaphorase histochemistry was performed in the SC of
adult rats sacrificed at different times from 1 h to 90 days after both SC
contusion or transection. NOS could first be seen 12 h after injury in axonal
swellings (AS) (club shaped structures at the tip of damage axons, associated
with tissue destruction). NOS expression reached a maximum 3 days after injury,
and gradually disappeared after 7 days. Finally, AS collapsed leaving behind
microcysts. NOS expression and the consequent production of nitric oxide could be
involved in the pathophysiology of the secondary damage, and/or could reflect a
failed attempt for axonal regeneration.
PMID- 9760143
TI - Characteristics of muscular contraction caused by magnetic stimulation.
AB - Characteristics of muscular contraction induced by magnetic stimulation were
studied using isolated gastrocnemius muscles of a frog. The figure-eight coil
position was regarded as 0 degrees when the direction of induced current was
parallel to the muscle fiber axis, and 90 degrees when the induced current was
perpendicular to the muscle fiber axis. Muscular contraction readily occurred
with lower outputs of magnetic stimulation at 0 degrees and 180 degrees, but it
was weak at 90 degrees and 270 degrees. Magnetic stimulation did not directly
induce muscular contraction but it acted on the synapses forming end plates to
muscle cells, and muscular contraction occurred if the direction of the eddy
current was parallel to the nerve which innervated the muscle cells.
PMID- 9760144
TI - Localization of a novel septin protein, hCDCrel-1, in neurons of human brain.
AB - Synaptic function is critical for cell-cell communication and the
characterization of proteins that function during vesicle formation, transport
and fusion events will yield further insight into the mechanisms of synaptic
transmission. We have cloned and characterized a gene product expressed in human
brain called hCDCrel-1. This protein is a new member of the septin family of gene
products that functions during cytokinesis in lower eukaryotes. In this study we
characterize the expression of the hCDCrel-1 gene and localize the hCDCrel-1
protein to neurons in adult human brain. hCDCrel-1 co-purifies with SNAP-25 and
synaptophysin marked synaptosomes, suggesting a novel function for this gene
family in the brain. Our data indicate that members of the septin family of
proteins may function in synaptic vesicle transport, fusion or recycling events
in the human brain.
PMID- 9760145
TI - Planum temporale asymmetries in great apes as revealed by magnetic resonance
imaging (MRI).
AB - The planum temporale (PT), a portion of Wernicke's area, is important for
linguistic functions in humans and is larger in the left compared to the right
hemisphere. In this study, we assessed the presence and size of the PT in a
sample of non-human primates including 21 great apes, four lesser apes, 11 Old
World monkeys and eight New World monkeys using magnetic resonance imaging. The
PT was measured in both the sagittal and coronal planes by use of multiplanar
reformatting software. The PT could only be identified in the sample of great
apes and not in the remaining non-human primate species. Within the great ape
sample, the PT was larger in the left hemisphere than in the right in a
statistical majority of the subjects. These results are consistent with the
notion that the PT evolved as a definable structure about 15 million years ago
and may have arisen as a result for selection for greater cortical folding which
in turn led to greater gyrification in larger brains.
PMID- 9760146
TI - Antisense strategies for the treatment of hematological malignancies and solid
tumors.
AB - If malignant growth is considered the result of abnormal gene expression, it is
reasonable to use antisense nucleic acids for the treatment of malignant
diseases. Antisense oligonucleotides can specifically down-regulate gene
expression, and a number of first-generation antisense compounds have entered
human clinical trials. In this review, some aspects relevant for the development
of antisense-based drugs, such as the selection of appropriate target sequences,
cellular delivery, and design of a clinical study, are described, using bcr-abl
oncogene-directed antisense oligonucleotides as an example. In addition,
potential target genes for antisense inhibition in hematology and oncology,
including oncogenes and adhesion molecules, are summarized. Down-regulation of
such adhesion molecules as members of the immunoglobulin superfamily and
integrins may provide new modalities for mobilization of CD34+ hematopoietic stem
cells into the peripheral blood. The review closes with an overview of ongoing
clinical trials in the treatment of malignant diseases by antisense
oligonucleotides.
PMID- 9760147
TI - Iron status in 268 Danish women aged 18-30 years: influence of menstruation,
contraceptive method, and iron supplementation.
AB - The aim of the present study was to evaluate the influence of menstruation,
method of contraception, and iron supplementation on iron status in young Danish
women, and to assess whether iron deficiency could be predicted from the pattern
of menstruation. Iron status was examined by measuring serum (S-) ferritin and
hemoglobin (Hb) in 268 randomly selected, healthy, menstruating, nonpregnant
Danish women aged 18-30 years. Iron deficiency (S-ferritin <16 microg/l) was
observed in 9.7%, of the women, iron deficiency anemia (S-ferritin < 13 microg/l
and Hb < 121 g/l) in 2.2%. Iron supplementation, predominantly as vitamin-mineral
tablets containing 14-20 mg of ferrous iron was used by 35.1%. The median serum
ferritin was similar in non-iron users and in iron users, whereas the prevalence
of iron deficiency was 12.6% in nonusers vs. 4.3% in users, the prevalence of
iron deficiency anemia 3.4% in nonusers vs. 0%, in users (p=0.17) In non-iron
supplemented women, S-ferritin levels were inversely correlated with the duration
of menstrual bleeding (rs= -0.25, p<0.001) and with the women's assessment of the
intensity of menstrual bleeding (r(s)= -0.27, p<0.001), whereas no such
correlations were found in iron-supplemented women. The results demonstrate that
even moderate daily doses of ferrous iron can influence iron status in women with
small iron stores. Women using hormonal contraceptives had menstrual bleeding of
significantly shorter duration than those using intrauterine devices (IUD) or
other methods. There was a high prevalence of small and absent body iron stores
in young women, suggesting that preventive measures should be focused on those
women whose menstruation lasts 5 days or longer, who have menstrual bleeding of
strong intensity, who use an IUD without gestagen, and who are blood donors.
PMID- 9760148
TI - Outcome of peripheral blood stem cell mobilization in advanced phases of CML is
dependent on the type of chemotherapy applied.
AB - High-dose chemotherapy with autologous transplantation of in vivo purged PBSC is
a novel investigational approach to treating chronic myelogenous leukemia (CML)
patients not responsive to conventional therapy with interferon-alpha (IFN-alpha)
and not eligible for allogeneic transplantation. PBSC mobilization using either
'5+2/7+3'-type chemotherapy or 'mini-ICE/ ICE' chemotherapy was investigated in
43 patients with advanced phases of Philadelphia (Ph)-positive CML. Thirty
patients were in late chronic phase (>12 months post diagnosis) and 13 patients
in accelerated phase (AP) or blast crisis (BC). Contamination with Ph-positive
cells was evaluated in harvests from 37/43 patients. The outcome of PBSC
mobilization was dependent on the type of chemotherapy administered: a complete
or major cytogenetic response (<35% Ph-positive metaphases) in leukapheresis
collections was obtained in ten of 15 patients treated with 'mini-ICE/ICE' but in
only three of 28 patients treated with '5 + 2/7 + 3' chemotherapy. One patient
(1/43) in blast crisis died during mobilization therapy (2%). Twenty-five
patients underwent PBSC transplantation and all of them engrafted successfully.
Transplantation-related mortality was 0%. The data show that in advanced phases
of CML the chance of harvesting Ph-negative peripheral blood stem cells depends
on the type of chemotherapy used for mobilization.
PMID- 9760149
TI - Time after bone marrow transplantation as an important variable for quality of
life: results of a cross-sectional investigation using two different instruments
for quality-of-life assessment.
AB - Quality of life (QoL) was investigated in 56 BMT recipients. The objective was to
compare QoL in terms of physical, emotional, and social functioning between
patients within the first year after BMT (n = 15) and patients who were alive
more than 1 year after BMT (n=41). The Functional Assessment of Cancer Therapy
Scale (FACT-BMT) and the EORTC-Quality of Life Questionnaire (EORTC-QLQ C30) were
used to evaluate QoL as perceived by the patients. Results show a significantly
reduced general QoL in patients within the first year after BMT. Specific
differences were identified on the dimensions of physical and emotional well
being and the symptom scales of appetite loss, fatigue, pain, dyspnea, and nausea
and vomiting. QoL improves significantly with time after BMT. We suggest that
there should be more integration of QoL expectancy into the pre-BMT information
process. Patients should be informed about potential deficits in physical and
emotional well-being within the first year after BMT. This could enhance insight
and compliance in the critical period early after BMT.
PMID- 9760150
TI - Effects of thrombopoietin on megakaryocyte colony formation from leukemic cells
at diagnosis and from marrow cells after induction chemotherapy for acute
leukemias.
AB - We have studied the effects of recombinant human thrombopoietin (TPO, mpl ligand)
on the megakaryocyte colony formation from control human bone marrow cells, human
leukemia cells at diagnosis, and human bone marrow cells after induction
chemotherapy for acute leukemias. In the control human bone marrow cells from
four adults and nine children who had localized malignancy and histologically
normal-looking marrow. TPO alone effectively stimulated megakaryocyte colony
formation, and interleukin-3 (IL-3) synergized this. In 17 patients (13 adults
and four children) with acute myeloid leukemia (AML) at diagnosis, TPO stimulated
leukemic colony formation in only one patient with FAB M7 subtype. In 11 children
with acute lymphoblastic leukemia (ALL) at diagnosis, TPO did not enhance
leukemic colony formation. After 17 courses of induction chemotherapy, nine for
AML and eight for ALL, TPO stimulated megakaryocyte colony formation to a level
of 51%, of that in the control human bone marrow cells. This may suggest that the
administration of TPO to patients with M7 subtype warrants caution, whereas it is
probably safe to give TPO at any time to patients with ALL. The administration of
TPO to patients with acute leukemias after induction chemotherapy could stimulate
megakaryocytopoiesis.
PMID- 9760151
TI - Early detection of chronic disseminated Candida infection in leukemia patients
with febrile neutropenia: value of computer-assisted serial ultrasound
documentation.
AB - Computer tomography (CT) is known to be as sensitive as magnetic resonance
imaging (MRI) in detecting fungal microabscesses in chronic disseminated
candidiasis. However, all imaging techniques have to be repeated in cases of
suspected fungal infection. Therefore, use of the CT or MRI scan is limited. Only
ultrasound (US) examinations can be repeated as often as needed. The disadvantage
of US is a lack of sufficient documentation. We analyzed the value of computer
assisted documentation in serial ultrasonography of leukemia patients with
suspected chronic disseminated candidiasis. From November 1996 until October
1997, a total of 220 ultrasound examinations (Kranzbuhler Logiq 500, 3.5 MHz
convex array) were performed in 58 patients undergoing intensive chemotherapy.
Initial US pictures were stored on a personal computer and compared with the live
US at the time of reevaluation in cases of persistent fever. Ultrasound detected
microabscesses in liver and/or spleen in eight of the 58 patients. Diagnosis was
confirmed by autopsy/biopsy (n = 6), blood culture (n = 1), and a significant
Candida antibody titer (n = 1). Focal lesions occurred only after neutrophil
recovery. However, a newly evolving nonhomogeneous, micronodular pattern of liver
and spleen occurred during febrile neutropenia in three patients, and two of
these developed focal lesions subsequently. Follow-up was easy, since US pictures
could be compared directly with stored examinations on screen. We conclude that
serial US is sensitive in detecting microabscesses in the liver or the spleen.
Computer-assisted US documentation proved to be a helpful tool for detection as
well as in the follow-up of patients with chronic disseminated candidiasis.
PMID- 9760152
TI - Type IV Ehlers-Danlos syndrome with platelet delta-storage pool disease.
AB - A case of type IV Ehlers-Danlos syndrome with a partial platelet delta-storage
pool disease is reported. The diagnosis of Ehlers-Danlos was clinical. The
platelet-dense granule deficiency was determined by ultrastructural platelet
morphology. Dense bodies were decreased in number, and most showed loss or
fragmentation of electron-dense material. Aggregation studies revealed a retarded
response to ristocetin and arachidonic acid, which was corrected with
desmopressin acetate-DDAVP.
PMID- 9760153
TI - Transient myeloproliferative disorder with 11q23 aberration in two neonates with
Down syndrome.
AB - Infants with Down syndrome may develop a transient myeloproliferative disorder
(TMD) with the features of acute leukemia but resolving in a spontaneous
remission. Chromosomal aberrations in addition to trisomy 21 have only rarely
been described. In many cases of infant acute leukemia band q23 of chromosome 11
is involved in nonrandom translocations, often resulting in a rearrangement of
the ALL-1 (MLL, HRX, HTRX 1) gene. Generally, this translocation carries a bad
prognosis. We describe two newborn girls with Down syndrome and TMD in whom the
constitutional trisomy 21 was combined with an acquired abnormality of chromosome
11. During the TMD the morphological and immunologic features were consistent
with those of megakaryoblastic leukemia. The chromosome 11 abnormalities were
del(ll)(q23), but rearrangements of the ALL-1 gene were not found. Our patients
had remissions that occurred spontaneously or after a mild chemotherapy. The
important finding is that additional chromosomal changes may occur during TMD in
Down syndrome. The fact that the abnormality was in region 11q23 raises the
question of whether the risk for developing leukemia is increased under these
conditions.
PMID- 9760154
TI - Molecular detection of a late-appearing BCR-ABL gene in a child with T-cell acute
lymphoblastic leukemia.
AB - Approximately 2-5% of children with newly diagnosed acute lymphoblastic leukemia
(ALL) have a Philadelphia (Ph) chromosome detectable on cytogenetic analysis,
which is associated with a poor prognosis. In rare ALL cases the Ph chromosome
may appear in leukemic cells during the course of the disease. We report here the
case of a 5.5-year-old male patient with T-ALL who was found to have the b2a2 BCR
ABL mRNA transcript by reverse transcriptase-polymerase chain reaction (RT-PCR)
at first marrow relapse. At the time of initial diagnosis, no BCR-ABL transcripts
had been detected by PCR in the patient's blood and marrow samples. Further
studies were performed using a competitive PCR titration assay and the
fluorescence in situ hybridization (FISH) method to monitor the leukemic clone.
Progression of the disease was associated with a higher BCR-ABL transcript level
and an increasing proportion of BCR-ABL-positive cells. Metaphase FISH analysis
identified the presence of the BCR-ABL fusion gene on a normal chromosome 22.
This study shows that a late-appearing Ph translocation in ALL may be
cytogenetically invisible. Quantitative RT-PCR and FISH techniques are
appropriate and efficient methods for detecting these rare ALL variants
expressing the BCR-ABL fusion gene and for estimating the level of residual
disease following treatment.
PMID- 9760155
TI - Sometimes it really is appendicitis: case of a CML patient with acute
appendicitis.
AB - We report on the case of a 24-year-old white man with a history of chronic
leukemia treated with unrelated bone marrow transplantation and chemotherapy who
was correctly diagnosed with appendicitis rather than typhlitis. The approach to
diagnosing an acute abdomen in the leukemic patient is discussed, with particular
focus on appendicitis vs. typhlitis. A focused CT scan proved to be instrumental
in making the correct diagnosis of appendicitis in our patient. The literature on
this topic for the past 30 years is reviewed. The purpose of our report is to
demonstrate that despite the recent trend toward diagnosing RLQ pain as typhlitis
which requires medical management, there are still instances where it 'really is'
appendicitis. Appendicitis, therefore, must always be ruled out in the leukemic
patient.
PMID- 9760156
TI - Bulky lymphadenopathy in acute myeloid leukemia.
AB - Two cases of acute myeloid leukemia (AML) presenting with bulky adenopathy are
reported. Both patients were febrile at admission and showed massive and diffuse
lymph node involvement, hepatomegaly, and splenomegaly. Erythematopapular
leukemic skin lesions were present in one case at the onset and developed in the
other at the time of relapse. Anemia, thrombocytopenia, and moderate leukocytosis
were present in both. The presence of immature cells in peripheral blood and bone
marrow allowed a rapid diagnosis of AML, FAB M1, in one patient. In the other
case, owing to the paucity of immature cells in peripheral blood and bone marrow,
lymph node biopsy with histology, imprint cytology, and immunocytochemistry were
essential for the diagnosis (AML, FAB M2, with trilineage dysplasia and
basophilic involvement). Both patients achieved complete remission (CR), followed
by an early relapse 3 months later. They underwent allogeneic bone marrow
transplantation (BMT) from HLA identical siblings. One patient is actually alive
and in CR at 6 months after BMT; the other patient showed a leukemic regrowth
after transplantation and died 4 months later.
PMID- 9760157
TI - Acute myelogenous leukemia (FAB AML-M1) in the setting of HIV infection and G-CSF
therapy: a case report and review of the literature.
AB - Although hematologic dysplasia is common in HIV disease, evolution to AML is
unusual. We report a case of AML in a patient with stage-C3 AIDS who had been
previously treated with granulocyte colony-stimulating factor (G-CSF). This 41
year-old black man presented with pancytopenia (Hg 8.6 g/dl, Hct 24.3%, platelets
16,000/mm3, WBC 0.6 x 10(3)/mm3) and hemoptysis. His peripheral smear manifested
19% blasts. His bone marrow biopsy was hypocellular (20%) with greater than 90%
blasts, which were positive for myeloperoxidase and Sudan black B. The blasts
were negative for nonspecific esterase. Immunophenotypic analysis by flow
cytometry showed the majority of cells to be of myeloid lineage, expressing CD13,
and CD45 at low intensity. In addition, there was aberrant expression of CD2 and
no expression of CD14 or CD4. The diagnosis of AML-FAB-M1 was made. The patient
refused chemotherapy. Of the rare cases of AML in HIV patients previously
reported in the literature, the majority were of the monocytic or myelomonocytic
subtype. This case is of special interest because of prior G-CSF therapy. In this
setting, the relationship between HIV, G-CSF, and subsequent AML is
controversial.
PMID- 9760158
TI - Cardiac involvement in HIV-related non-Hodgkin's lymphoma: a case report and
short review of the literature.
AB - We report a case of secondary heart involvement in AIDS-related primary lymphoma
of the liver. A worsening dyspnea led to the diagnosis of pericardial effusion,
and transesophageal echocardiography revealed the presence of large endocardial
ventricular masses. Clinical suspicion of a lymphomatous origin was confirmed at
the autopsy, which showed an extranodal dissemination pattern (heart, liver,
intestine, and lung). In AIDS patients, both primary and secondary lymphomatous
heart involvement are increasing in incidence. Clinical symptoms and signs are
vague. Since the hematogenous route is the most common pattern of involvement,
even extrathoracic lymphomas can present heart dissemination. Thus, it should be
suspected in lymphoma patients who present with even mild aspecific heart
symptoms. Appropriate imaging procedures include transesophageal echocardiography
and, if possible, ECG-gated MRI. A negative transthoracic echocardiograph does
not exclude the presence of myocardial tumor. Chemotherapy is only occasionally
beneficial, and the prognosis remains poor.
PMID- 9760159
TI - Extramedullary granulopoiesis mimicking recurrent lymphoma after prolonged
administration of human recombinant granulocyte colony-stimulating factor.
AB - Human recombinant granulocyte colony-stimulating factor (G-CSF) has become a
treatment of choice for neutropenia of diverse etiologies. We describe a 71-year
old man who, while receiving G-CSF for graft failure after peripheral blood stem
cell transplant, developed dramatic extramedullary granulopoiesis that mimicked
recurrent lymphoma.
PMID- 9760160
TI - Chlorambucil-induced pulmonary disease: a case report and review of the
literature.
AB - A 77-year-old man developed pneumonitis while on chlorambucil therapy for chronic
lymphocytic leukemia, with a cumulative dose of 2700 mg. The condition improved
promptly with the discontinuation of the drug and initiation of steroids. A case
report and review of the literature are presented in this paper.
PMID- 9760162
TI - Monofunctional platinum amine complexes destabilize DNA significantly.
AB - Both cis-[Pt(NH3)2(4-Me-Py)Cl]+ and trans-[Pt(NH3)2(4-Me-Py)Cl]+ bind DNA
covalently at the N7 site of guanine residues forming mono-dentate adducts.
However, like cisplatin and transplatin, only the cis isomer has anti-cancer
activity, whereas the trans-isomer does not. In order to understand the molecular
basis of the different activities associated with cis-[Pt(NH3)2(4-Me-Py)Cl]+ and
trans-[Pt(NH3)2(4-Me-Py)Cl]+, the interactions of these two platinum compounds
with the DNA heptamer CCTG*TCC:GGACAGG duplex (G* is the platinated guanine) have
been examined. The reaction rate of cis-[Pt(NH3)2(4-Me-Py)Cl]+ with the single
stranded CCTGTCC is significantly faster than that of the trans isomer. The
solution structure of the platinum-DNA adducts has been studied by two
dimensional NMR spectroscopy. Both the cis-platinum adducts and the trans
platinum adducts destabilize the DNA duplex significantly. The melting
temperature (Tm) of the platinated heptamer duplex is estimated to be 10 degrees
C lower than for the unplatinated duplex by NMR. At 2 degrees C, the base pairs
located on the 5' side of the oligonucleotide, beyond the platinum lesion site,
are disrupted. Over time, the platinum-DNA complex decomposes and the cis
[Pt(NH3)2(4-Me-Py)] platinum complex is gradually detached from DNA. No
interstrand crosslinking is observed. The biological implications of the
structural studies are discussed.
PMID- 9760161
TI - Rapid tumor lysis in a patient with B-cell chronic lymphocytic leukemia and
lymphocytosis treated with an anti-CD20 monoclonal antibody (IDEC-C2B8,
rituximab).
AB - In this report we present a patient with B-cell chronic lymphocytic leukemia who
developed an acute tumor lysis syndrome after administration of the human anti
CD20 antibody IDEC-C2B8 (RITUXIMAB) in standard dose of 375 mg/m2. IDEC-C2B8 has
been demonstrated to have only mild and tolerable side effects in patients with
follicular lymphoma. In these trials patients with lymphocytosis >5000/microl
were excluded. Physicians must be aware of this hitherto unreported phenomenon in
patients with high CD20-positive blood counts.
PMID- 9760163
TI - 800 MHz 1H NMR solution structure refinement of oxidized cytochrome c7 from
Desulfuromonas acetoxidans.
AB - The solution structure of Desulfuromonas acetoxidans cytochrome c7 has been
refined by using 1H-NMR spectra recorded at 800 MHz and by using pseudocontact
shifts in the final energy minimization procedure. The protein, composed of 68
amino acids, contains three paramagnetic heme moieties, each with one unpaired
electron. The largely distributed paramagnetism broadens the lines in several
protein parts. The structure is now relatively well resolved all over the
backbone by the use of 1315 meaningful NOEs and 90 pseudocontact shifts. The
statistical analysis of the structure indicates its satisfactory quality. The
protein-fold is quite similar to that of the analogous four-heme cytochromes c3
for those parts which can be considered homologous. The solvent accessibility and
the electrostatic potential surfaces surrounding the three hemes have been
analyzed in terms of their reduction potentials. The resulting magnetic
susceptibility anisotropy data obtained from pseudocontact shifts are analyzed in
terms of structural data.
PMID- 9760164
TI - Monitoring the conformational flexibility of cytochrome c at low ionic strength
by 1H-NMR spectroscopy.
AB - Horse heart cytochrome c at pH 7 and low ionic strength is present as two
conformers, as evidenced by 1H-NMR spectroscopy. The two structures have been
calculated using NOE and pseudocontact shift constraints. They have the same
folding patterns and are essentially equal, within the rmsd of the families. The
two average structures have rmsd values of 0.049 nm and 0.093 nm for the backbone
and the heavy atoms, respectively. Such a difference has been analyzed through a
detailed analysis of the NOEs. It appears that the species at low ionic strength
differs from the species present at high ionic strength by the displacement of
some external residues, such as Gln16, Ile81 and Glu90. Other changes are
monitored by the chemical shifts but they cannot be quantified at the present
level of resolution. Ionic-strength-dependent structural rearrangements may be
relevant with respect to the problem of molecular recognition.
PMID- 9760165
TI - Solution structure of the cellulose-binding domain of endoglucanase I from
Trichoderma reesei and its interaction with cello-oligosaccharides.
AB - The solution structure of a synthetic 38-residue cellulose-binding domain (CBD)
of endoglucanase I from Trichoderma reesei (CBD(EGI)) was determined by two
dimensional 1H-NMR spectroscopy. 100 structures were generated from a total of
599 NOE derived distance restraints and 28 phi and 14 chi dihedral angle
restraints. For the final set of 19 selected structures, the rms deviation about
the mean structure was 0.83+/-0.26 A for all atoms and 0.50+/-0.22 A for the
backbone atoms. The structure of CBD(EGI) was very similar to that of CBD of
cellobiohydrolase I from T reesei (CBD(CBHI)). The backbone trace of CBD(EGI)
followed closely the irregular triple-stranded antiparallel beta-sheet structure
of CBD(CBHI). Moreover, apart from the different side chains of Trp7 (CBD(EGI))
and Tyr5 (CBD(CBHI)), the cellulose-binding face of CBD(EGI) was similar to that
of CBD(CBHI) within the precision of the structures. Finally, the interaction
between CBD(EGI) and soluble sugars was investigated using cellopentaose and
cellohexaose as substrates. Experiments showed that the interactions between
CBD(EGI) and cellobiose units of sugars are specific, supporting the previously
presented model for the CBD binding to crystalline cellulose.
PMID- 9760166
TI - Structural characteristics of bullfrog (Rana catesbeiana) transthyretin and its
cDNA--comparison of its pattern of expression during metamorphosis with that of
lipocalin.
AB - Transthyretin, an extracellular thyroid-hormone-binding protein (THBP) in higher
vertebrates, is synthesized and secreted by the choroid plexus of all classes of
vertebrates, except fish and amphibians, and synthesized in the liver of
endothermic animals. Here, we report the nucleotide sequence of the cDNA for a
THBP found in plasma of bullfrog (Rana catesbeiana) tadpoles before the climax of
metamorphosis. The amino acid sequence clearly shows this protein to be an
amphibian transthyretin. The three-dimensional structure of bullfrog
transthyretin was derived using homology modeling. Compared with transthyretins
from other vertebrate species, bullfrog transthyretin is highly conserved at the
thyroid hormone-binding sites and other important structural regions of the
subunits. Bullfrog transthyretin mRNA was found in tadpole liver, but not in
tadpole choroid plexus. Thus, during evolution, synthesis of transthyretin in the
liver of metamorphosing amphibians preceded that in the choroid plexus of
reptiles, birds and mammals. It was previously observed that the protein most
abundantly synthesized and secreted by the choroid plexus in adult amphibians is
a lipocalin [Achen, M. G., Harms, P. J., Thomas, T., Richardson, S. J.,
Wettenhall, R. E. H. & Schreiber, G. (1992) J. Biol. Chem. 267, 23170-23174], in
contrast to transthyretin being the most abundantly synthesized and secreted
protein in the choroid plexus of mammals, birds and reptiles. Lipocalin mRNA was
found in large amounts in tadpole choroid plexus, but not livers.
PMID- 9760167
TI - An isopeptide bond splitting enzyme from Hirudo medicinalis similar to gamma
glutamyl transpeptidase.
AB - A new enzyme from Hirudo medicinalis capable of splitting gamma-glutamyl-p
nitroanilide and Glu--Lys-(N6-gamma-glutamyllysine) (isopeptidic bond between the
epsilon-amino group of lysine and the gammacarboxylic group of glutamic acid)
isopeptide bonds was purified. The protein was partially sequenced at the amino
acid level, and the complete nucleotide and amino acid sequences were determined
after cDNA cloning. The new enzyme has more than 60% similarity at the amino acid
level to vertebrate gammaglutamyl transpeptidase (gamma-GT). According to the
cDNA, the new protein has a molecular mass of 65 521 Da and a length of 600 amino
acids.
PMID- 9760168
TI - Interferon-gamma variants with deletions in the AB surface loop--flexibility is a
critical point for receptor binding.
AB - The receptor-binding AB loop of recombinant human interferon-gamma (IFN-gamma)
has multiple contacts with the extracellular part of the IFN-gamma receptor a
chain (IFN-gammaRalpha). We explored the possible length of truncated AB loops
and their conformations by molecular modelling. Deletions of two amino acids at
the tip of the loop were tolerated in the model without van der Waals collisions
of the AB loop with helix F. Based on these modelling results, two deletion
mutants were constructed by overlap-extension PCR mutagenesis: des-(A23, D24)-IFN
gamma and des-(N25, G26)-IFN-gamma. Both mutations were tolerated by the folding
pattern of recombinant human IFN-gamma, as proved by CD spectroscopy. The
stability of both mutants against cosolvent-induced unfolding was equal to that
of wild-type IFN-gamma. In contrast to the biophysical similarities of wild-type
and mutant IFN-gamma proteins, the biological activities of both mutants dropped
significantly. Antiviral activity and human leucocyte antigen (HLA)-DR induction
of des-(N25, G26)-IFN-gamma was 10% that of wild-type activity. des-(A23, D24)
IFN-gamma had only 1% remaining activity. Receptor-binding experiments confirmed
that both deletions had a negative influence on the affinity of recombinant human
IFN-gamma to its cellular receptor. We conclude from this combined molecular
modelling and mutagenesis experiments, that the reduced flexibility of the
truncated AB loop abrogates the possibility of the formation of a 3(10) helix in
the receptor-bound state as observed in the X-ray structure of the IFN
gammaRalpha-IFN-gamma complex.
PMID- 9760169
TI - Probing the inhibitor-binding site of aldose reductase with site-directed
mutagenesis.
AB - Aldose reductase (AR) has been implicated in the etiology of the secondary
complications of diabetes, and enzyme inhibitors have been proposed as
therapeutic agents. While effectively preventing the development of diabetic
complications in animals, results from clinical studies of AR inhibitors have
been disappointing, possibly due to poor potency in man. To assist in the design
of more potent and specific inhibitors, crystallographic studies have attempted
to identify enzyme-inhibitor interactions. Resolution of crystal complexes has
suggested that the inhibitors bind to the enzyme active site and are held in
place through hydrogen bonding and van der Waals interactions formed within two
hydrophobic pockets. To confirm and extend these findings we quantified inhibitor
activity with single, site-directed, mutant, human AR enzymes in which the apolar
active-site residues tryptophan 20, -79, -111 and phenylalanine 115 were replaced
with alanine or tyrosine, decreasing the potential for van der Waals
interactions. Consistent with molecular models, the inhibitory activity of
Tolrestat, Sorbinil and Zopolrestat decreased 800-2000-fold when tested with the
mutant enzyme in which Trp20 was replaced with alanine. Further, alanine
substitution for Trp111 decreased Zopolrestat's activity 400-fold, while
mutations to Trp79 and Phe115 had little effect on the activity of any of the
inhibitors. The alanine mutation at Trp111 had no effect on Tolrestat's activity
but decreased the activity of Sorbinil by about 1000-fold. These latter effects
were unanticipated based on the number of non-bonded interactions between the
inhibitors, Tolrestat and Sorbinil, and Trp20 and Trp111 that have been
identified in the crystal structures. In spite of these unexpected findings, our
results are consistent with the hypothesis that AR inhibitors occupy the enzyme
active site and that hydrophobic interactions between the enzyme and inhibitor
contribute to inhibitor binding stability.
PMID- 9760170
TI - The crystal structure of anionic salmon trypsin in complex with bovine pancreatic
trypsin inhibitor.
AB - The complex formed between anionic salmon trypsin (ST) and bovine pancreatic
trypsin inhibitor (BPTI) has been crystallised, and the X-ray structure has been
solved using the molecular replacement method. The crystals are hexagonal and
belong to space group P6(1)22 with lattice parameters of a = b = 83.12 A and c =
222.15 A. Data have been collected to 2.1 A and the structure has been refined to
a crystallographic R-factor of 20.6%. Catalysis by salmon trypsin is
distinguished by a Km value 20-fold lower than that for mammalian trypsins, and a
k(cat) twice as high. The present ST-BPTI complex serves as a model for the
Michaelis-Menten complex, and has been compared with corresponding bovine and rat
trypsin (RT) complexes. The binding of BPTI to salmon trypsin is characterised by
stronger primary interactions in the active site, and a somewhat looser secondary
binding.
PMID- 9760171
TI - Hypothermia enhances the biological activity of lipopolysaccharide by altering
its fluidity state.
AB - Lipopolysaccharides (LPS, endotoxin) of gram-negative bacteria are among the main
causes of sepsis and septic shock. In the present study, the influence of
temperature on the biological activity of LPS was investigated. Lowering the
temperature from 37 degrees C to 34.5 degrees C or to 30 degrees C significantly
enhances in vitro tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta
and IL-6 release induced by different LPS chemotypes and heat-inactivated
Escherichia coli. This cytokine-increasing effect of lowering the temperature is
highly mediated by serum proteins, particularly by LPS-binding protein (LBP) and
low-density lipoproteins (LDL). In contrast, cytokine production induced by the
superantigen toxic shock syndrome toxin-1 (TSST-1) from Gram-positive
Staphyloccoccus aureus decreases by around 70% at 30 degrees C as compared with
37 degrees C, corresponding to the expected effect of change in temperature and
regardless of the presence of serum proteins. In order to explain the unexpected
biological hypothermia effect with regard to LPS, the fluidity state of the lipid
A portion of LPS as one important physico-chemical property possibly involved was
investigated. The fluidity, determined by fluorescence polarization measurements,
was found to decrease with decreasing temperature. These data suggest that a low
fluid LPS chemotype is biologically more active than a more fluid one (and vice
versa). Statistical analysis of the results shows a strong correlation between
cytokine secretion and fluidity state of a given LPS chemotype (0.71 < r < 0.89,
all P<0.01). As a clinical consequence, these data may be one possible
explanation for the higher mortality rate of hypothermic Gram-negative sepsis.
PMID- 9760172
TI - Induction of the heat-shock response by antiviral prostaglandins in human cells
infected with human immunodeficiency virus type 1.
AB - Cyclopentenone prostaglandins inhibit the replication of several DNA and RNA
viruses, including retroviruses. The antiviral activity has been associated with
the induction of a 70-kDa heat-shock protein (HSP70), via activation of the heat
shock transcription factor (HSF) in infected cells. In the present study we
investigated the effect of prostaglandin A1 (PGA1) on the regulation of HSP70
gene expression as well as on viral RNA and protein synthesis in CEM-SS cells
during acute infection with human immunodeficiency virus type 1 (HIV-1). We
report that HIV-1 infection does not alter HSF activation by PGA1, whereas it
causes an increase in intracellular HSP70 mRNA levels, as a result of enhanced
HSP70 mRNA stability. We also show that, as reported in studies of different
virus/host cell models, PGA1 inhibits HIV-1 replication by acting at multiple
levels during HIV-1 infection. In addition to the previously reported block of
HIV-1 mRNA transcription, PGA1 was also found to inhibit viral protein synthesis.
These results, together with the fact that prostaglandins are used clinically in
the treatment of several diseases, open new perspectives in the search for novel
antiretroviral drugs.
PMID- 9760173
TI - Antiproliferative effects of SR31747A in animal cell lines are mediated by
inhibition of cholesterol biosynthesis at the sterol isomerase step.
AB - SR31747A is a new sigma ligand exhibiting immunosuppressive properties and
antiproliferative activity on lymphocyte cells. Only two subtypes of sigma
receptor, namely the sigma1 receptor and emopamil-binding protein, have been
characterised molecularly. Only the sigma1 receptor has been shown to bind (Z)N
cyclohexyl-N-ethyl-3-(3-chloro4-cyclohexylphenyl)pro pen-2-ylamine hydrochloride
(SR31747A) with high affinity. It was demonstrated that the SR31747A effect on
the inhibition of T-cell proliferation was consistent with a sigma1 receptor
mediated event. In this report, binding experiments and sterol isomerase assays,
using recombinant yeast strains, indicate that the recently cloned emopamil
binding protein is a new SR31747A-binding protein whose activity is inhibited by
SR31747A. Sterol analyses reveal the accumulation of a delta8-cholesterol isomer
at the expense of cholesterol in SR31747A-treated cells, suggesting that
cholesterol biosynthesis is inhibited by SR31747A at the delta8-delta7 sterol
isomerase step in animal cells. This observation is consistent with a sterol
isomerase role of the emopamil-binding protein in the cholesterol biosynthetic
pathway in animal cells. In contrast, there is no evidence for such a role of the
sigma1 receptor, in spite of the structural similarity shared by this protein and
yeast sterol isomerase. We have found that SR31747A also exerts anti
proliferative effects at nanomolar concentrations on various established cell
lines. The antiproliferative activity of SR31747A is reversed by cholesterol.
Sterol-isomerase overproduction enhances resistance of CHO cells. This last
observation strongly suggests that sterol isomerase is implicated in the
antiproliferative effect of the drug in established cell lines.
PMID- 9760174
TI - Subunits composition and allosteric control in Carcinus aestuarii hemocyanin.
AB - Carcinus aestuarii hemocyanin (Hc) exists in two aggregation forms at pH 7.5 and
20 mM Ca2+: 24S accounting for 90% of total hemocyanin and 16S accounting for
10%. Removal of metal cations by EDTA at neutral pH causes the complete
dissociation of 24S hemocyanin into two different 16S. At pH 9.2, 24S hemocyanin
dissociates into a pH stable 16S and a 5S component. The 5S component consists of
three monomeric fractions named CaeSS1 (10%), CaeSS2 (50%) and CaeSS3 (40%); the
latter fraction consisting of two isoforms. The fractions CaeSS1, CaeSS2 and
CaeSS3 have been studied as far as their reassociation properties to form
hexamers are concerned. We investigated the oxygen-binding properties of the
native form (24S), the mixture of the two 16S forms, the pH-stable 16S alone and
of purified subunit fractions to define the role of each species on the
expression of the allosteric behaviour of the 24S aggregate. The analysis of O2
binding data reveals that 24S-Hc can be well described by the modified Monod
Wyman and Changeaux-model (nested MWC-model), while the half-molecules (16S) bind
oxygen according to the simple MWC-model. The two hexameric 16S within the
dodecameric 24S hemocyanin can be regarded as nested allosteric units. They
behave as being functionally coupled in the T-states (tT and rT). In the R-states
(tR and rR) the two half-molecules seem to be functionally uncoupled since they
have the same values of oxygen binding constants as deduced for isolated 16S
hexamers.
PMID- 9760175
TI - Expression of a bioactive, single-chain choriogonadotropin in Dictyostelium
discoideum.
AB - Human choriogonadotropin (hCG) is a highly complex glycoprotein consisting of two
non-covalently associated subunits. We aimed for the expression of a single-chain
hCG in the soil amoebae Dictyostelium discoideum, a host which, in principle,
provides simple genetics in combination with complex protein synthesis. To limit
anticipated problems in mRNA translation, the first 30 bases of the coding
sequence were altered to conform to the Dictyostelium preferred codon usage. We
show that, immunologically, active single-chain hCG is indeed produced by
Dictyostelium. Furthermore, this single-chain hCG is able to bind to the human
luteinizing hormone/CG receptor and elicit a biological response. Its receptor
binding affinity is comparable to single-chain hCG produced by mammalian cells.
We conclude that Dictyostelium is able to express bioactive highly complex
heterologous glycoproteins.
PMID- 9760176
TI - Characterization of an acetyl-11-keto-beta-boswellic acid and arachidonate
binding regulatory site of 5-lipoxygenase using photoaffinity labeling.
AB - AKBA (acetyl-11-keto-beta-boswellic acid), a natural pentacyclic triterpene, is
an orally active leukotriene-synthesis inhibitor, which acts by a 5-lipoxygenase
directed, non-redox, non-competitive mechanism. It is the only leukotriene
synthesis inhibitor so far identified that inhibits 5-lipoxygenase activity as an
allosteric regulator and not by a reducing or competitive mechanism. To
characterize AKBA's effector site we prepared azido125I-KBA (4-azido-5-125iodo
salicyloyl-beta-alanyl-11-keto-beta-bo swellic acid) as a photoaffinity analogue,
which inhibited 5-lipoxygenase activity as efficiently as the lead compound and
specifically labeled human 5-lipoxygenase protein. The labeling of 5-lipoxygenase
by azido-125I-KBA strictly depended on the presence of calcium ([Ca2+]free > 500
nM) and was abolished by heat denaturation or by prior incubation with a series
of pentacyclic triterpenes (e.g., amyrin, beta-boswellic acid, AKBA and 18a
glycyrrhetinic acid). In contrast, 18-beta-glycyrrhetinic acid and competitive 5
lipoxygenase inhibitors (e.g., ZM-230,487 and L-739,010) did not affect labeling.
Arachidonic acid, in enzyme-activity-inhibiting concentrations, reduced
photoincorporation (IC50 about 10 microM), whereas a variety of other long-chain
fatty acids and their derivatives (e.g., arachidinic acid, arachidonic acid
methyl ester, lipoxins A4 and B4) had no effect. The inhibitory arachidonate
action on labeling was not affected by blocking the substrate-binding site by
micromolar amounts of the competitive inhibitor L-739,010. Therefore, we suggest
that AKBA binds in presence of calcium to a site which is distinct from the
substrate binding site of 5-lipoxygenase. The AKBA-binding site is likely to be
identical with a regulatory, second arachidonate binding site of the enzyme.
PMID- 9760177
TI - Dipeptidyl-peptidase IV-beta--further characterization and comparison to
dipeptidyl-peptidase IV activity of CD26.
AB - Dipeptidyl peptidase IV-beta (DPP IV-beta) is a novel protein which shows a
peptidase activity similar to the T-cell-activation antigen CD26. To further
characterize this DPP IV-beta and confirm its cell surface expression, we have
developed a purification strategy using the CD26- cell line C8166. The
purification process includes biotinylation of cell surface proteins before
preparation of cell extracts and processing by gel-filtration, ion-exchange and
lectin chromatographies. Consistent with the molecular mass of DPP IV-beta
estimated by gel-filtration chromatography, the final purified fraction,
manifesting a typical DPP IV activity, showed a major biotinylated 75-80-kDa band
in SDS/PAGE, thus suggesting the monomeric nature of this enzyme. Kinetic
parameters of DPP IV-beta and the sensitivity to a new family of irreversible DPP
IV inhibitors, were studied in comparison to CD26. Both enzymes followed a
Michaelis kinetics with different Km values for Gly-Pro-NH-Np (NH-Np, para
nitroanilide) hydrolysis (0.28+/-0.05 mM and 0.12+/-0.02 mM). More significant
differences were observed in the sensitivity to inhibitors, which exerted a much
higher activity on CD26 than on DPP IV-beta. These differences permitted us to
study DPP IV-beta expression in CD26-expressing cells, showing the expression of
this new enzyme in all lymphoid cells tested, and a rapid enhancement in
phytohemagglutinin-stimulated or protein-A-stimulated peripheral blood
mononuclear cells. Our results indicate that, although DPP IV-beta and CD26 are
coexpressed and manifest a typical DPP IV activity, there are distinct features
in their catalytic activities that may confer to each enzyme a complementary role
in peptide processing.
PMID- 9760178
TI - Changing transcription start sites in H-type alpha(1,2)fucosyltransferase gene
(FUT1) during differentiation of the human erythroid lineage.
AB - Recent studies have suggested that at least three transcription-initiation sites
were present in the human H-type alpha(1,2)fucosyltransferase gene (FUT1). In the
present study, we have investigated these transcription start sites of FUT1 in
undifferentiated leukemic cells (K562) that have erythroid characteristics, in
erythroleukemia cells (HEL), and in bone marrow cells. K562 cells used
exclusively exon 1 as the start site. While HEL cells used mainly exon 2 as the
start site, the major start site for bone marrow cells was within exon 7. In
addition, we investigated the transcription start site(s) in vascular endothelial
cells (ECV304) as an example of mature cells and found that the start site was
predominantly within exon 7. The promoter activities were found in the 5'
flanking regions of these three start sites after transfection of constructs with
luciferase reporter gene into K562 and HEL cells. These findings suggested that
the transcription start sites of FUT1 changed during differentiation of the
erythroid lineage and that the tissue-specific and stage-specific expressions of
the FUT1 were regulated by three distinct promoters. We also found that the 5'
flanking region of exon 2 (intron 1) consisted of repetitive sequences
(chromosome 19-specific 37-bp minisatellite repeats, Alu sequence and long
terminal repeat) and that the start site of exon 2 was within the long terminal
repeat. Thus, these repetitive sequences may play a role in the expression of the
FUT1.
PMID- 9760179
TI - The effect of two actin depolymerizing factors (ADF/cofilins) on actin filament
turnover: pH sensitivity of F-actin binding by human ADF, but not of Acanthamoeba
actophorin.
AB - Actin depolymerizing factor (ADF) from vertebrates and actophorin from
Acanthamoeba castellanii are members of a protein family that bind monomeric and
polymeric actin and have been shown by microscopy to sever filaments. Here, we
compare the properties of recombinant human ADF and actophorin using rabbit
muscle actin. ADF binds tenfold more strongly than actophorin to monomeric actin
(G-actin)-ATP, and both bind co-operatively to F-actin. ADF decorates filaments
below pH 7.3 and induces substantial depolymerization at higher pH values
[Hawkins, M., Pope, B., Maciver, S. K. & Weeds, A. G. (1993) Human actin
depolymerizing factor mediates a pH-sensitive destruction of actin filaments,
Biochemistry 32, 9985-9993], but, at all pH values tested, actophorin binds to
filaments in a similar manner to ADF at pH 6.5. Both proteins increase the
depolymerization rate at the pointed ends of gelsolin-capped filaments, but the
effect of ADF is more marked at pH 8.0. Both proteins accelerate the nucleating
activity when mixed with filamentous actin (F-actin), but not with gelsolin
capped filaments, and they rapidly decrease the lengths of filaments as evidenced
by electron microscopy. Both of these effects are best explained by a weak
severing activity. Our results are discussed in relation to earlier models and to
the structural changes observed when ADF binds F-actin [McGough, A., Pope, B.,
Chiu, W. & Weeds, A. (1997) Cofilin changes the twist of F-actin: implications
for actin filament dynamics and cellular function, J. Cell Biol. 138, 771-781].
We also discuss the relevance of these observations to their possible roles in
facilitating actin turnover in cells, thereby regulating filament dynamics in
cell motility.
PMID- 9760180
TI - Mutual conversion of fatty-acid substrate specificity by a single amino-acid
exchange at position 527 in P-450Cm2 and P-450Alk3A.
AB - The two eukaryotic fatty-acid hydroxylases P-450Cm2 and P-450Alk3A, which
represent CYP52A4 variants naturally occurring in the yeast Candida maltosa, were
characterized with respect to their substrate specificity. Whereas P-450Cm2 was
found to catalyse lauric acid omega-hydroxylation with greater efficiency, P
450Alk3A had higher palmitic acid turnover numbers compared to P-450Cm2,
resulting in ratios of lauric acid to palmitic acid turnover rates of nearly 11
and 3 for P-450Cm2 and P-450Alk3A, respectively. As shown by means of chimeric
enzymes and site-directed mutagenesis, the key residue determining these
differences in substrate specificity was found to be a single amino acid at
position 527. Interestingly, the mutual exchange of valine (P-450Cm2) and leucine
(P-450Alk3A) led to a direct transposition of specificity, suggesting that amino
acids at this site may determine the efficiency of fatty-acid hydroxylation
relatively independently of other active-site residues. This was further
supported by the finding that P-450Cm2 and P-450Alk3A with methionine at position
527 displayed almost identical hydroxylation activities. Moreover, methionine to
leucine substitutions at the corresponding alignment position in P-450Cm1
(CYP52A3), P-450Alk2A (CYP52A5) and P-450Alk5A (CYP52A9) altered the fatty-acid
specificity of these enzymes. In comparison to the structure of the bacterial P
450BM3 (CYP102), we propose that the amino acid at position 527 may serve to
close the substrate-binding pocket near to the haem in the fatty-acid-omega
hydroxylating P-450 of the CYP52 family.
PMID- 9760182
TI - Analysis of the ternary complex formation of human urokinase with the separated
two domains of its receptor.
AB - Human urokinase-type-plasminogen-activator receptor (uPAR) is a glycolipid
anchored membrane glycoprotein comprising three structurally similar domains. We
have succeeded in direct observation of the ternary complex formation of single
chain urokinase (scuPA) or its N-terminal fragment (ATF) with the separated
domain-1 (N-terminal domain) and domain-(2+3) (internal and C-terminal domain) of
human uPAR, by means of gel-filtration HPLC analysis. This complex was found to
consist of the three components in an equimolar ratio (thus referred to as the
three-part complex). To determine the nature of the interaction between these
components, cross-linking experiments involving various kinds of cross-linkers
and competitive binding assay on ELISA were performed. These experiments have
shown that each uPAR domain can bind directly to scuPA at low affinity, and that
both these domains contribute to the high-affinity binding between scuPA and uPAR
in a synergistic manner. It can be considered that the synergistic effect of
domain-1 and domain-(2+3) on scuPA binding would result from a conformational
change, and that this steric event might trigger the signal transduction reported
for scuPA/uPAR binding.
PMID- 9760181
TI - Solution structure of thanatin, a potent bactericidal and fungicidal insect
peptide, determined from proton two-dimensional nuclear magnetic resonance data.
AB - Thanatin is the first inducible insect peptide that has been found to have, at
physiological concentrations, a broad range of activity against bacteria and
fungi. Thanatin contains 21 amino acids including two cysteine residues that form
a disulfide bridge. Two-dimensional (2D) 1H-NMR spectroscopy and molecular
modelling have been used to determine its three-dimensional (3D) structure in
water. Thanatin adopts a well-defined anti-parallel beta-sheet structure from
residue 8 to the C-terminus, including the disulfide bridge. In spite of the
presence of two proline residues, there is a large degree of structural
variability in the N-terminal segment. The structure of thanatin is quite
different from the known structures of other insect defence peptides, such as
antibacterial defensin and antifungal drosomycin. It has more similarities with
the structures of various peptides from different origins, such as brevinins,
protegrins and tachyplesins, which have a two-stranded beta-sheet stabilized by
one or two disulfide bridges. Combined with activity test experiments on several
truncated isoforms of thanatin, carried out by Fehlbaum et al. [Fehlbaum, P.,
Bulet, P., Chernysh, S., Briand, J. P., Roussel, J. P., Letellier, L., Hetru, C.
& Hoffmann, J. (1996) Proc. Natl Acad. Sci. USA 93, 1221-1225], our structural
study evidences the importance of the beta-sheet structure and also suggests that
anti-Gram-negative activity involves a site formed by the Arg20 side-chain
embedded in a hydrophobic cluster.
PMID- 9760183
TI - Molecular analysis of Chs3p participation in chitin synthase III activity.
AB - Chitin is a minor but essential component of the cell wall of Saccharomyces
cerevisiae, with functions in septum formation in the vegetative life cycle and
also in conjugation and spore cell-wall synthesis in the sexual cycle. Of the
three chitin synthases present in yeast, chitin synthase III (CSIII) is
responsible for the synthesis of most of the chitin found in the cell, including
a chitin ring at early budding, chitin interspersed in the cell wall, and chitin
laid down during the sexual cycle. We have tagged Chs3p, the putative catalytic
subunit of CSIII, with the immunoreactive epitope of influenza virus
hemagglutinin to follow expression of the protein. Little correlation was found
between the levels of transcription and translation of Chs3p and in vivo
function, supporting our previous conclusion that regulation of CSIII occurs at
the posttranslational level. To identify possible regions of the protein involved
in catalysis or regulation, mutations were generated in the QRRRW 'signature
sequence' of chitin synthases. Arginine residue mutations in Chs3p, and in Chs1p
and Chs2p, resulted in a loss of both function in vivo and enzymatic activity.
Mutations in a serine residue adjacent to glutamine in Chs3p caused loss of
function in vivo with a moderate decrease in CSIII activity, suggesting a
regulatory role for the serine residue in chitin biosynthesis. Several
truncations in the unique hydrophilic carboxy-terminal region of Chs3p identified
a sequence of about 25 amino acids that is required for both function and in
vitro activity. Since this region is not present in Chs1 or Chs2, it may be
involved in the specific regulation of CSIII.
PMID- 9760184
TI - Molecular and pharmacological characterization of recombinant rat/mice N-methyl-D
aspartate receptor subtypes in the yeast Saccharomyces cerevisiae.
AB - The genes encoding the ionotropic N-methyl-D-aspartate (NMDA) receptor subunits
NR1a, NR2B and NR2D were cloned in the multi-copy yeast-Escherichia coli shuttle
vectors pMBO1 and pMB02. The protease-deficient yeast Saccharomyces cerevisiae
c13-ABYS-86 (leu-, ura-, his-) was transformed with the recombinant plasmids
pMBNR1a (leu+), pMBNR1a/pMBNR2D (ura+), pMBNR1a/pMBNR2D/ pMBNR2B (his+) or
pMBNR1a/pMBNR2A/pMBNR2B, respectively, and was used to express the different NMDA
receptor subunit genes. Western-blotting analysis with the specific NMDA receptor
antibodies showed a clear but differently strong expression of the recombinant
receptor proteins which were found to be only partially glycosylated in the cell
membranes of the recombinant yeast strains. By immunofluorescence microscopy
using the specific subunit antibodies and fluorescence-labeled secondary
antibodies, the distinctly expressed NR1a and NR2D subunits could be located in
the plasma membrane of the transformed yeast cells. Pharmacological
characterization of crude membrane preparations of the recombinant yeast cells
expressing 1-3 NMDA receptor subunits showed saturable binding of the glycine
antagonist [3H]MDL105,519 with different Kd values of 56.88+/-5.38 nM (NR1a),
1365.11+/-76 nM (NR1a/NR2D), 22.97+/-3.37 nM for NR1a/NR2B/NR2D and 7.4+/-1.2 nM
for NR1a/NR2A/NR2B. The bound capacities were 13.07+/-0.92 (NRla), 14.63+/-0.50
(NR1a/NR2D), 12.85+/-1.68 (NR1a/NR2B/NR2D) and 8.3+/-0.7 (NR1a/NR2A/NR2B) pmol/mg
membrane protein. The [3H]MDL105,519 binding was inhibited by the glycine
antagonist 5,7-dichlorokynurenate (DCKA), ethyl-2-carboxy-4.6-dichloro-3
indoleacetate (ECDI) and itself, but not by glycine, D-serine and 1-amino
cyclopropanecarboxylic acid (ACPC). Each of these recombinant receptor proteins
consisting both of NR1 and NR2 subunits also showed a specific binding site for
the NMDA agonist glutamate when using L-[3H]glutamate as a radioligand. Analysis
of saturation experiments revealed that this ligand binds to a specific site with
Kd values of 536+/-43, 688+/-60, and 856+/-48 nM for NR1a/NR2B, NR1a/NR2D, and
NR1a/NR2B/NR2D respectively.
PMID- 9760185
TI - Conserved sequence elements in human main type-H1 histone gene promoters: their
role in H1 gene expression.
AB - In man, the H1 class of histones consists of seven different isoforms, termed
H1.1-H1.5, H1t and H1o. Analysis of the promoters of the respective genes reveals
that all seven H1 gene promoters share conserved sequence elements: a TATA box at
around position -25 (relative to the transcription start site), a CCAAT motif at
about position -50 (except in the H1 promoter), an H1-box (AAACACA) around
position -110 (except in the H1.1 promoter), and the highly conserved motif
TGTGT/CTA (TG-box or CH1UE) at around nucleotide position -450 (except in the
H1.1 promoter). Analysis of the H1.3 gene promoter was carried out with reporter
gene assays (using the luciferase gene as a reporter gene) including stepwise
deletion and site-directed mutagenesis. In addition, electrophoretic mobility
shift assays were carried out for the analysis of protein/DNA interactions at
conserved promoter motifs. Mutation analysis indicates that the CH1UE motif is
involved in mediating the S-phase-dependent expression of the H1.3 gene.
Comparison of H1 promoters shows that the CCAAT-box is extended in each case by
CA. Mutational analysis indicates that only the CCAATCA heptanucleotide, but not
just the CCAAT sequence mediates the effect of this element in H1 gene promoters.
PMID- 9760186
TI - Fusion of two subunits does not impair the function of a [NiFeSe]-hydrogenase in
the archaeon Methanococcus voltae.
AB - [NiFe]-hydrogenases generally carry the bimetallic Ni-Fe reaction center on their
largest subunit. The [NiFeSe]-hydrogenase Vhu from Methanococcus voltae has an
unusual subunit composition. Some of the amino acids participating in the
formation of the reaction center are within a separate, very small subunit,
called VhuU. It consists of only 25 amino acids and contains the selenocysteinyl
residue, a ligand to the Ni atom. We have tested whether the special
configuration of the Vhu-hydrogenase is of particular biochemical relevance. We
have constructed a fusion subunit derived from the VhuA and VhuU subunits by
generating a gene fusion which was inserted into the chromosome of M. voltae by
gene replacement. The enzyme was purified and shown to be as active as the wild
type enzyme. M. voltae carries the genetic information for four different [NiFe]
hydrogenases. In addition to the Vhu-hydrogenase, a second selenium-containing
enzyme, Fru, has been purified. Two selenium-free enzymes, Vhc and Frc, are
homologues of Vhu and Fru, respectively. Their gene groups, vhc and frc are
transcribed only upon selenium depletion. The selenium-containing subunit VhuU
has been implicated in their negative regulation. However, cells containing the
fusion hydrogenase still exhibited normal regulation of the vhc andfrc promoter
activities as tested in reporter gene constructs. This indicates that the free
VhuU polypeptide is not required for the negative regulation of the vhc or frc
genes.
PMID- 9760187
TI - Biochemical characterization and crystal structure of a recombinant hen avidin
and its acidic mutant expressed in Escherichia coli.
AB - The mature hen avidin encoded by a synthetic cDNA was expressed in Escherichia
coli in an insoluble form. After resolubilization, renaturation and purification,
a recovery of about 20 mg/l cell culture was obtained. ELISA assays indicated no
apparent differences in biotin binding between the natural and recombinant
avidins. In addition, an acidic avidin mutant, bearing the substitutions Lys3-
>Glu, Lys9--> Glu, Arg26-->Asp and Arg124-->Leu of four exposed basic residues,
was produced. The protein, expressed and renatured as wild-type avidin, showed
unaltered biotin-binding activity. The acidic pI (approximately 5.5) and lack of
aggregation of the mutant allowed easy electrophoretic analysis under non
denaturing conditions of the protein alone and of its complexes with biotin,
biotinylated transferrin or peroxidase. Analysis of the sera from sensitized
subjects revealed that the avidin mutant has altered antigenicity. Both
recombinant avidins were crystallized and the three-dimensional structures solved
by molecular replacement and refined to 0.22 nm resolution. The three-dimensional
structures of the two recombinant molecules, in the absence of biotin and of
glycosylation, are fully comparable with those of the natural hen avidin
previously reported.
PMID- 9760188
TI - Two distinct forms of human mast cell chymase--differences in affinity for
heparin and in distribution in skin, heart, and other tissues.
AB - Chymase, a chymotrypsin-like protease secreted by human mast cells, is generally
considered to be a single enzyme. However, by heparin-agarose chromatography of
high-salt extracts of human skin, we have consistently resolved three peaks of
chymotryptic activity, eluting at 0.4 M NaCl (peak A), 1.0-1.2 M NaCl (peak B)
and 1.8-2.0 M NaCl (peak C), with peak B containing 75-90% of the recovered
activity. Each peak retained its identity upon rechromatography. The three peaks
of activity were similar in substrate specificity and inhibitor profile and
distinctly different from other chymotryptic enzymes, including cathepsin G and
the stratum corneum chymotryptic enzyme. Examination of different tissues
revealed that peak C was virtually absent from synovial tissue, was present as a
minor component in skin and heart, but constituted the predominant chymotryptic
activity in lung. Peaks B and C from skin tissue were further purified by
chromatography on Sephacryl S-200. Both had a molecular mass of 28-29 kDa,
yielded the N-terminal sequence reported for chymase, and on western blots
reacted with a panel of polyclonal, monoclonal and antipeptide antibodies against
chymase. Chymase C required higher concentrations of NaCl to overcome the
stimulatory effects of heparin than did chymase B, but had a similar pH profile.
Thus, human chymase exists in at least two distinct but similar forms, and the
differences in heparin binding and tissue distribution could have important
consequences for enzyme function.
PMID- 9760189
TI - Sulfated di-, tri- and tetraantennary N-glycans in human Tamm-Horsfall
glycoprotein.
AB - The primary structures of 32 sulfated di-, tri- and tetraantennary N-glycans of
human Tamm-Horsfall glycoprotein (THP) have been determined. THP was isolated
from the urine of one healthy male donor. The intact carbohydrate chains were
released by PNGase-F and fractionated via FPLC on Resource Q, HPLC on LiChrosorb
NH2, and high-pH anion-exchange chromatography on CarboPac PA-1.
Characterizations were performed using 500-MHz and 600-MHz 1H-NMR spectroscopy,
in combination with sialidase treatments. The type of characterized N-glycans
ranged from monosulfated to trisulfated N-glycans, whereby the sulfate groups
were present as 3-O-sulfated Gal (Gal3S) and 4-O-sulfated GalNAc (GalNAc4S). A
compilation of the established structures is shown below. [structure in text]
PMID- 9760190
TI - Structural and serological studies on a new acidic O-specific polysaccharide of
Proteus vulgaris O32.
AB - The following structure of the O-specific polysaccharide chain (O-antigen) of the
Proteus vulgaris 032 lipopolysaccharide (LPS) was established by 1H-NMR and 13C
NMR spectroscopy, including two-dimensional NOESY and H-detected 1H,13C
heteronuclear multiple-quantum coherence (HMQC) experiments: -->2)-alpha-L-RhapI
(1-->2)-alpha-L-RhapII-(1-->4)-beta-D-++ +GalpA(I)-(1-->3)-beta-D-GlcpNAc-(1-->4)
alpha-D-GalpA(II)-(1-- >. In addition, an O-acetyl group was detected, which,
most probably, is located at position 3 of a part of RhapI residues. Serological
studies, using rabbit polyclonal anti-(P. vulgaris 032) serum, homologous and
heterologous Proteus O-antigens and related artificial antigens, revealed the
importance of an a-D-GalA-associated epitope in manifesting the immunospecificity
of P. vulgaris 032 and substantiated serological relationships between the O
antigen studied and those of some other Proteus strains.
PMID- 9760191
TI - Beta-1,3-galactosyltransferase and alpha-1,2-fucosyltransferase involved in the
biosynthesis of type-1-chain carbohydrate antigens in human colon adenocarcinoma
cell lines.
AB - We studied the beta-1,3-galactosyltransferase (GalT) and alpha-1,2
fucosyltansferase (FT) involved in the biosynthesis of type-1-chain carbohydrate
antigens in human colon adenocarcinoma cell lines. We detected a GalT activity
able to use GlcNAc as acceptor and found that lacto-N-biose I (Galbeta1-3GlcNAc)
is the only reaction product. Such beta1,3GalT is kinetically similar to a pig
trachea enzyme involved in mucin synthesis. The specific activity is high in
cells that react strongly with anti-Lewis a and anti-Lewis b antibodies, and
undetectable in a cell line that lacks antibody reaction. Reverse-transcriptase
mediated PCR analysis followed by DNA sequencing indicated that secretor-type
alpha1,2FT is expressed in the cells, while the H type alpha1,2FT is not. The
apparent Km values for donor and acceptor substrates determined for alpha1,2FT
are similar to those of secretor-type alpha1,2FT and the specific activity
measured correlates with Lewis b antigen expression on the cell surface.
Moreover, some of the cell lines express Lewis y and H type 2 antigens,
indicating that secretor type alpha1,2FT is responsible for their synthesis.
Results suggest that biosynthesis of type-1-chain tumor-associated antigens in
human colon carcinoma cells is operated by secretor-type alpha1,2FT, as reported
in normal mucosa, and that beta1,3GalT activity may play a relevant role in its
control.
PMID- 9760193
TI - Localization of a gene for incomplete X-linked congenital stationary night
blindness to the interval between DXS6849 and DXS8023 in Xp11.23.
AB - Congenital stationary night blindness (CSNB) is a nonprogressive retinal disorder
characterized by night blindness, nystagmus, myopia, a variable decrease in
visual acuity, an abnormal electroretinographic response, and a disturbance in
dark adaptation. Two forms of X-linked CSNB have been defined, complete CSNB in
which rod function is extinguished, and incomplete CSNB in which rod function is
reduced but not extinguished, as seen by electroretinography and dark
adaptometry. In studying a large family of Mennonite ancestry, we have confirmed
linkage between the locus (CSNB2) for incomplete CSNB and genetic markers in the
Xp11 region. In particular, lod scores of 12.25 and 15.26 at zero recombination
were observed between CSNB2 and the markers DXS573 and DXS255. Detailed analysis
of critical recombinant chromosomes in this extended family have refined the
minimal region for the CSNB2 locus to the interval between DXS6849 and DXS8023 in
Xp11.23.
PMID- 9760192
TI - The SOX10/Sox10 gene from human and mouse: sequence, expression, and
transactivation by the encoded HMG domain transcription factor.
AB - The SOX genes form a gene family related by homology to the high-mobility group
(HMG) box region of the testis-determining gene SRY. We have cloned and sequenced
the SOX10 and Sox10 genes from human and mouse, respectively. Both genes encode
proteins of 466 amino acids with 98% sequence identity. Significant expression of
the 2.9-kb human SOX10 mRNA is observed in fetal brain and in adult brain, heart,
small intestine and colon. Strong expression of Sox10 occurs throughout the
peripheral nervous system during mouse embryonic development. SOX10 shows an
overall amino acid sequence identity of 59% to SOX9. Like SOX9, SOX10 has a
potent transcription activation domain at its C-terminus and is therefore likely
to function as a transcription factor. Whereas SOX9 maps to 17q, a SOX10 cosmid
has previously been mapped by us to the region 22q13.1. Mutations in SOX10 have
recently been identified as one cause of Waardenburg-Hirschsprung disease in
humans, while a Sox10 mutation underlies the mouse mutant Dom, a murine
Hirschsprung model.
PMID- 9760194
TI - Characterization of the human synaptogyrin gene family.
AB - Genomic sequencing was combined with searches of databases for identification of
active genes on human chromosome 22. A cosmid from 22q13, located in the
telomeric vicinity of the PDGFB (platelet-derived growth factor B-chain) gene,
was fully sequenced. Using an expressed sequence tag-based approach we
characterized human (SYNGR1) and mouse (Syngr1) orthologs of the previously
cloned rat synaptogyrin gene (RATSYNGR1). The human SYNGR1 gene reveals three
(SYNGR1a, SYNGR1b, SYNGR1c) alternative transcript forms of 4.5, 1.3 and 0.9 kb,
respectively. The transcription of SYNGR1 starts from two different promoters,
and leads to predicted proteins with different N- and C-terminal ends. The most
abundant SYNGR1 a transcript, the 4.5-kb form, which corresponds to RATSYNGR1, is
highly expressed in neurons of the central nervous system and at much lower
levels in other tissues, as determined by in situ hybridization histochemistry.
The levels of SYNGR1b and SYNGR1c transcripts are low and limited to heart,
skeletal muscle, ovary and fetal liver. We also characterized two additional
members of this novel synaptogyrin gene family in human (SYNGR2 and SYNGR3), and
one in mouse (Syngr2). The human SYNGR2 gene transcript of 1.6 kb is expressed at
high levels in all tissues, except brain. The 2.2-kb SYNGR3 transcript was
detected in brain and placenta only. The human SYNGR2 and SYNGR3 genes were
mapped by fluorescence in situ hybridization to 17qtel and 16ptel, respectively.
The human SYNGR2 gene has a processed pseudogene localized in 15q11. All
predicted synaptogyrin proteins contain four strongly conserved transmembrane
domains, which is consistent with the M-shaped topology. The C-terminal
polypeptide ends are variable in length, display a low degree of sequence
similarity between family members, and are therefore likely to convey the
functional specificity of each protein.
PMID- 9760195
TI - Japanese juvenile retinoschisis is caused by mutations of the XLRS1 gene.
AB - We investigated the XLRS1 gene in Japanese patients with retinoschisis (RS). All
exons of the XLRS1 gene were sequenced in 14 males, including a pair of
monozygotic twins, from 11 individual families with RS and five of their mothers
who are asymptomatic but diagnosed as carriers. Six kinds of missense mutations
and a nonsense mutation, including six novel mutations, were detected in all 14
patients and carriers. Mutations in the XLRS1 gene are also responsible for RS in
non-Caucasian patients. Most Japanese RS cases are caused by an XLRS1 gene
defect. A novel mutation, Glu72Lys, was found in four families, suggesting a
common mutation in the Japanese population. Clinical features of RS patients with
both the Glu72Lys and Pro193Leu mutations indicate that a genotype-phenotype
correlation is not recognized in RS.
PMID- 9760196
TI - Phenotypic variation in a family with mutations in two Hirschsprung-related genes
(RET and endothelin receptor B).
AB - Hirschsprung disease is a congenital malformation affecting 1 in 5000 live
births. The absence of parasympathetic neuronal ganglia (Meissner, Auerbach) in
the hindgut results in poor coordination of peristaltic movement, and a varying
degree of constipation. Four different genes have been implicated in the
pathogenesis of Hirschsprung disease: the RET tyrosine kinase receptor gene; one
of its ligands, the glial cell line-derived neurotrophic factor (GDNF) gene; the
endothelin receptor B (EDNRB) gene; and its ligand, endothelin-3 (EDN3).
Recently, combinations of mutations in two of these genes (RET and GDNF) have
been reported in Hirschsprung patients. We report a family with missense
mutations in both the RET gene (R982C) and the EDNRB gene (G57S). In this family,
three out of five members have the two mutations, but only one, a boy, has the
Hirschsprung disease phenotype. This illustrates the complexity of the molecular
background of Hirschsprung disease.
PMID- 9760197
TI - Missense mutation and hexanucleotide duplication in the PAX2 gene in two
unrelated families with renal-coloboma syndrome (MIM 120330).
AB - We present a family with autosomal-dominant inheritance of renal insufficiency
caused by renal hypoplasia in six individuals. In all affected individuals, signs
of optic disk dysplasia were detected, but most patients were asymptomatic. A
heterozygous missense mutation in the PAX2 gene causing a Gly75 to Ser
substitution was present in all affected individuals. A second, unrelated patient
presented with ocular complaints related to optic disk dysplasia, and had a
history of vesico-ureteral reflux. A heterozygous hexanucleotide duplication in
the PAX2 gene was detected leading to the duplication of GluThr at positions 74
and 75. The mutations in these two families are the first mutations in the PAX2
gene that do not lead to a truncated protein. Mechanistically, these mutations
are expected to result in abnormal folding of the PAX2 protein. These
observations further expand the spectrum of clinical features associated with
PAX2 mutations, and suggest that a distinct genetic disorder can be identified in
patients with renal dysplasia through a careful eye examination. As the ocular
manifestations in this syndrome are variable anomalies of retinal and optic disk
dysplasia, we prefer the term "papillo-renal syndrome".
PMID- 9760198
TI - A high proportion of mutations in the BRCA1 gene in German breast/ovarian cancer
families with clustering of mutations in the 3' third of the gene.
AB - We have analyzed 61 German breast and breast/ovarian cancer families for BRCA1
mutations using single-strand conformation polymorphism analysis (SSCP) followed
by sequencing. Forty-seven of the families had at least three cases (at least two
under 60 years) and 14 families had only two cases of breast/ovarian cancer (at
least one under 50 years). Twenty-eight families were breast/ovarian and 33 were
breast cancer-only families. Eighteen mutations in BRCA1 were detected in 11/28
breast/ovarian cancer families and 7/33 breast cancer families and none in the
families with only two cases. We identified 17 truncation mutations (8
frameshift, 7 nonsense and 2 splice variants) and one missense mutation. Seven of
these are novel and two, the 5382insC and 5622C-->T mutations, occurred in two
apparently unrelated families. The genotype of the two families with the 5382insC
mutation is compatible with the rare haplotype segregating with the 5382insC
mutation in different populations, further supporting its European origin. One
unclassified missense alteration, R841W, was found in one family but did not
segregate with the disease, suggesting that it is more likely a polymorphism. We
also report and discuss the sequence of several new unclassified single
nucleotide changes first identified by SSCP. Of the 18 mutations, 13 occurred in
the 3' third of the gene (end of exon 11-24) and ovarian cancers were found in
eight of these families.
PMID- 9760199
TI - Mutations in the pterin-4alpha-carbinolamine dehydratase (PCBD) gene cause a
benign form of hyperphenylalaninemia.
AB - Four patients with primapterinuria, postulated to be due to pterin-4alpha
carbinolamine dehydratase (PCD) deficiency, were diagnosed by biochemical and DNA
analysis. All four patients presented in the neonatal period with
hyperphenylalaninemia, and elevated neopterin and decreased biopterin levels in
the urine. These symptoms are common to 6-pyruvoyltetrahydropterin synthase
deficiency and thus there is a danger of misdiagnosis. In addition, all four
patients had elevated urinary excretion of primapterin (7-biopterin), the only
persistent biochemical abnormality. Analysis of fibroblast DNA from the patients
identified the following mutations in the PCBD gene: one patient homozygous for
the missense mutation E96K and one homozygous for the nonsense mutation Q97X,
both in exon 4; one compound heterozygote with the mutations E96K and Q97X; and
one patient with two different homozygous mutations: E26X in exon 2 and R87Q in
exon 4. In two families, the parents were investigated and found to be obligate
heterozygotes for particular mutations. One sibling was found to be unaffected.
These results further substantiate the idea that primapterinuria is associated
with mutations in the PCBD gene.
PMID- 9760200
TI - Nine novel germline mutations of STK11 in ten families with Peutz-Jeghers
syndrome.
AB - Peutz-Jeghers Syndrome (PJS) is an autosomal dominant hereditary disease
characterized by hamartomatous polyposis involving the entire bowel. Recently
STK11, a gene bearing a mutation responsible for PJS, was isolated. We
investigated the entire coding region of STK11 in 15 unrelated PJS families by
the PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism)
method and PCR-direct sequence analysis, and found nine different, novel
mutations among ten of those families. One nonsense mutation and five different
frameshift mutations (two families carried the same mutation), all of which would
cause truncation of the gene product, were found in seven families; mutations
found in five families were clustered within exon 6. Among these five mutations,
three occurred at the mononucleotide-repeat region (CCCCCC) of codons 279-281,
suggesting that this region is likely to be a mutational hotspot of this gene.
One of the remaining three families carried a 3-bp in-frame deletion that would
eliminate an asparagine residue within a kinase domain of the product; the other
two carried intronic mutations at or adjacent to the consensus dinucleotide
sequences of splice-acceptor or -donor sites, which were likely to lead to
aberrant splicing.
PMID- 9760201
TI - Molecular characterization and delineation of subtle deletions in de novo
"balanced" chromosomal rearrangements.
AB - To test the hypothesis that the phenotypic abnormalities seen in cases with
apparently balanced chromosomal rearrangements are the result of the presence of
cryptic deletions or duplications of chromosomal material near the breakpoints,
we analyzed three cases with apparently balanced chromosomal rearrangements and
phenotypic abnormalities. We characterized the breakpoints in these cases by
using microsatellite analysis by polymerase chain reaction and fluorescence in
situ hybridization analysis of yeast artificial chromosome clones selected from
the breakpoint regions. Molecular characterization of the translocation
breakpoint in patient 1 [46,XY,t(2;6)(p22.2;q23.1)] showed the presence of a 4-
to 6-Mb cryptic deletion between markers D6S412 and D6S1705 near the 6q23.1
breakpoint. Molecular characterization of the proximal inversion 7q22.1
breakpoint in patient 2 [46,XY,inv(7)(q22.1q32.1)] revealed the presence of a 4
Mb cryptic deletion between D7S651 and D7S515 markers. No deletion or duplication
of chromosomal material was found near the breakpoints in patient 3
[46,XX,t(2;6)(q33.1;p12.2)]. Our study suggests that a systematic molecular study
of breakpoints should be carried out in cases with apparently balanced
chromosomal rearrangements and phenotypic abnormalities, because cryptic
deletions near the breakpoints may explain the phenotypic abnormalities in these
cases.
PMID- 9760202
TI - A novel splice site mutation in the tissue inhibitor of the metalloproteinases-3
gene in Sorsby's fundus dystrophy with unusual clinical features.
AB - Sorsby's fundus dystrophy (SFD) is an autosomal dominant macular dystrophy which
is developed usually in the third or fourth decade of life, and is characterized
by central visual loss and nyctalopia due to fundus changes of exudative or
atrophic macular lesions. Its functional prognosis is usually poor because of
disciform macular scars and peripheral chorioretinal atrophies. To date, five
different mutations in the tissue inhibitor of the metalloproteinases-3 (TIMP3)
gene have been identified in families of a wide geographic origin, all of which
are missense mutations that cause replacement by cysteine of conserved amino
acids in the C-terminus of exon 5 of TIMP3. We have studied two Japanese families
with SFD, the first report from the Eastern world, and identified a novel 3'
splice site mutation in the TIMP3 gene, namely a single base insertion at the
intron 4/exon 5 junction which converts the consensus sequence CAG to CAAG in the
splice acceptor site. In addition, our patients displayed a distinctive clinical
expression in that they developed macular dystrophies at an approximately 30-year
later age of onset and preserved functional vision until later life with
essentially uninvolved peripheral retina. The present findings may provide some
insight into the genotype-phenotype relationship in SFD.
PMID- 9760203
TI - Genetics strongly determines the wall thickness of the left and right carotid
arteries.
AB - In 76 supposedly healthy families, we investigated the familial resemblance of
left and right carotid intima-media thickness (IMT) measured by B-mode
ultrasonography and the impact of the common apolipoprotein E (apo E)
polymorphism and the insertion/deletion polymorphism of the angiotensin
converting enzyme (ACE). Genetic factors accounted for about 30% of IMT
variation. The insertion/deletion ACE polymorphism did not influence carotid IMT,
whereas apoE polymorphism explained about 1.5% of only right carotid IMT
variability independently of cholesterol levels. The apo epsilon2 and apo
epsilon4 alleles were associated with lower right carotid IMT than was the apo
epsilon3 allele. We conclude that genetic factors strongly contribute to IMT
variability in healthy people and that the apo E polymorphism may be one of these
factors.
PMID- 9760205
TI - The Usher syndrome in the Lebanese population and further refinement of the USH2A
candidate region.
AB - Usher syndrome (USH) is an autosomal-recessive disease characterized by
neurosensory deafness and progressive retinitis pigmentosa. So far, three
clinical types of Usher syndrome have been defined, and are caused by defects at
more than eight loci. We report the linkage analysis of seven Lebanese families
with Usher syndrome, two with type I (USH1) and five with type II (USH2). We
demonstrate that one family is linked to the USH1C locus, a rare form of USH1
only reported in the French Acadian population. Linkage analysis of the five USH2
families with recently mapped loci allowed us to reduce the USH2A candidate
region to a very small interval flanked by D1S2646/D1S2629 and D1S2827.
Furthermore, haplotype comparison between the different families suggests a
founder effect for the USH2A mutation among the different Lebanese ethnic groups,
while a genetic heterogeneity is noted for Usher syndrome type I.
PMID- 9760206
TI - Linkage disequilibrium and linkage analysis of the glucose-6-phosphatase gene.
AB - Recent studies have indicated that the four most common mutations account for 78%
of mutant alleles in the glucose-6-phosphatase (G6Pase) gene. A significant
fraction of mutant alleles remain unidentified. Thus, informative polymorphic
markers are necessary for linkage analysis in carrier testing and prenatal
diagnosis in families where mutations can not be identified. The common mutations
appear to be ethnic-specific, suggesting that the individual mutations may have a
common founder. With the recent discovery of the nucleotide 1176 polymorphism, we
have studied whether these mutations are in linkage disequilibrium with the
polymorphism. The results of polymerase chain reaction/allele-specific
oligonucleotide analysis show that nucleotide 1 176 C is in linkage
disequilibrium with mutations R83 C and R83H, and with the splicing mutation 727G
->T. The 1176T polymorphism is in linkage disequilibrium with 459insTA. A GT
repeat polymorphism has also been found. However, its heterozygosity is low. The
1176 nucleotide polymorphic marker can be used in carrier and prenatal diagnosis
of GSD1a families that have unidentified mutations and are informative for this
marker.
PMID- 9760204
TI - Molecular cloning of the chromosomal breakpoint in the LIS1 gene of a patient
with isolated lissencephaly and balanced t(8;17).
AB - Karyotypic analysis of a patient exhibiting a phenotype of isolated
lissencephaly, and of her parents, revealed a de novo balanced translocation,
t(8;17)(p11.2; p13.3). Since the lissencephaly (LIS1) gene was known to be
located on 17p13.3, we investigated whether the translocation might involve this
gene. We performed Southern analysis using cosmid clones that contained genomic
sequences corresponding to LIS1, and found that the breakpoint was located within
intron 1. As sequence analysis of the parental chromosomes in the vicinity of the
breakpoint identified no additional putative transcripts, haploinsufficiency of
the LIS1 gene is likely to be solely responsible for the patient's lissencephaly.
Characterization of both breakpoints indicated a possible involvement of
repetitive sequences in the recombigenic process that led to the translocation.
PMID- 9760207
TI - Extensive polymorphism of the FUT2 gene in an African (Xhosa) population of South
Africa.
AB - The human secretor type alpha(1,2)fucosyltransferase gene (FUT2) polymorphism was
investigated in Xhosa and Caucasian populations of South Africa by polymerase
chain reaction-restriction fragment length polymorphism and DNA sequencing. Six
new base substitutions were found in the coding region of FUT2. A single base (C)
deletion at nucleotide 778, which led to a frame shift and produced a stop codon
at codon 275, was responsible for the enzyme inactivation. Three nonsynonymous
base substitutions, A40G (lle14Val), C379T (Arg127Cys), and G481A (Asp161Asn),
and two synonymous base substitutions, A375G (Glu125) and C480T (His160), were
also identified in functional alleles. As a result, seven new alleles, Se40,
Se481, Se40,481, Se357,480, Se357,379,480, Se375, and se357,480,778 were
identified. Population studies revealed that an allele containing a nonsense
mutation G428A (Trp143stop) (se428) was the common null allele in both Xhosa and
Caucasian populations, whereas an allele containing a missense A385T (Ile129Phe)
mutation (se357,385), which is the common null allele in Orientals, was found to
be absent from both populations. The heterozygosity rates of FUT2 genotypes were
as high as 0.75 in the Xhosa population and 0.65 in the Caucasian population.
Therefore, the extensive polymorphism and race specificity of the FUT2 gene make
it suitable for application as a new tool in genetic studies of modern human
evolutionary history.
PMID- 9760208
TI - A global survey of haplotype frequencies and linkage disequilibrium at the DRD2
locus.
AB - A four-site haplotype system at the dopamine D2 receptor locus (DRD2) has been
studied in a global sample of 28 distinct populations. The haplotype system spans
about 25 kb, encompassing the coding region of the gene. The four individual
markers include three TaqI restriction site polymorphisms (RSPs) -- TaqI "A",
"B", and "D" sites -- and one dinucleotide short tandem repeat polymorphism
(STRP). All four of the marker systems are polymorphic in all regions of the
world and in most individual populations. The haplotype system shows the highest
average heterozygosity in Africa, a slightly lower average heterozygosity in
Europe, and the lowest average heterozygosities in East Asia and the Americas.
Across all populations, 20 of the 48 possible haplotypes reached a frequency of
at least 5% in at least one population sample. However, no single population had
more than six haplotypes reaching that frequency. In general, African populations
had more haplotypes present in each population and more haplotypes occurring at a
frequency of at least 5% in that population. Permutation tests for significance
of overall disequilibrium (all sites considered simultaneously) were highly
significant (P<0.001) in all 28 populations. Except for three African samples,
the pairwise disequilibrium between the outermost RSP markers, TaqI "B" and "A",
was highly significant with D' values greater than 0.8; in two of those
exceptions the RSP marker was not polymorphic. Except for those same two African
populations, the 16-repeat allele at the STRP also showed highly significant
disequilibrium with the TaqI "B" site in all populations, with D' values usually
greater than 0.7. Only four haplotypes account for more than 70% of all
chromosomes in virtually all non-African populations, and two of those haplotypes
account for more than 70% of all chromosomes in most East Asian and Amerindian
populations. A new measure of the amount of overall disequilibrium shows least
disequilibrium in African populations, somewhat more in European populations, and
the greatest amount in East Asian and Amerindian populations. This pattern seems
best explained by random genetic drift with low levels of recombination, a low
mutation rate at the STRP, and essentially no recurrent mutation at the RSP
sites, all in conjunction with an "Out of Africa" model for recent human
evolution.
PMID- 9760209
TI - Variation of site-specific methylation patterns in the factor VIII (F8C) gene in
human sperm DNA.
AB - The methylation status of 12 CpG sites in three exons of the human factor VIII
(F8C) gene was examined by bisulphite genomic sequencing of human sperm DNA from
14 European Caucasians and Asians. Different CpG sites were found to vary in
their methylation status both within and between individuals. Strand differences
in methylation status were also detected at certain sites, a finding that could
reflect hemi-methylation. No evidence for systematic deviations in methylation
status were found between the two ethnic groups. Only a limited correlation was
observed between the level of methylation of specific CpG sites in sperm DNA and
their mutability, a finding that is probably attributable to the pattern of
methylation observed in mature spermatocytes not being representative of that of
the germline.
PMID- 9760210
TI - An ecological study of association between coronary heart disease mortality rates
in men and the relative frequencies of common allelic variations in the gene
coding for apolipoprotein E.
AB - Three common alleles, epsilon2, epsilon3, and epsilon4, of the gene coding for
apolipoprotein E (apoE) have been identified as predictors of interindividual
variation in measures of lipid and lipoprotein metabolism, and ultimately risk of
coronary heart disease (CHD), within many populations. Here we evaluated the
utility of the geographic distribution of these alleles for prediction of
interpopulation variation in average level of serum total cholesterol and other
traditional risk factors, and CHD mortality rate. We employed published estimates
of the relative frequencies of the three common apoE alleles, average levels of
risk factors such as serum total cholesterol, systolic and diastolic blood
pressure, body mass index, smoking prevalence and CHD mortality rate for nine
population-based samples of middle-aged males studied by the international WHO
MONICA Project. There was approximately a 10-fold difference between the highest
and lowest CHD mortality rate. Of the traditional risk factors, variation in the
average level of serum total cholesterol was the best predictor (approximately
33%) of the observed interpopulation variation in estimates of CHD mortality rate
(Pr=0.10). Variation in the relative frequency of the epsilon4 allele predicted
approximately 50% of interpopulation variation in average serum total cholesterol
level (Pr=0.02) and 75% of the variation in CHD mortality rate (Pr=0.002) when
information about variation in the other risk factors and the epsilon2 and
epsilon3 alleles is ignored. Furthermore, variation in the relative frequency of
the epsilon4 allele predicted approximately 40% of the variation in CHD mortality
rate (Pr=0.02) after considering the contribution of variation in average serum
total cholesterol level. Average serum total cholesterol level was estimated to
increase by 0.114 mmol/l (4.405 mg/dl), and CHD mortality rate by 24.5/100000,
for an increase of 0.01 in the relative frequency of the epsilon4 allele. The
predictive utility of the epsilon2 and epsilon3 alleles was considerably less
than that of the epsilon4 allele. For the sample of populations considered, the
geographic distribution of the apoE alleles can be a statistically significant
predictor of interpopulation variation in both the average serum total
cholesterol level and CHD mortality rate. In particular, the epsilon4 allele may
confer valuable ecological risk information.
PMID- 9760212
TI - Molecular characterization and mutational analysis of the human B17 subunit of
the mitochondrial respiratory chain complex I.
AB - Bovine NADH:ubiquinone oxidoreductase (complex 1) of the mitochondrial
respiratory chain consists of about 36 nuclear-encoded subunits. We review the
current knowledge of the 15 human complex I subunits cloned so far, and report
the 598-bp cDNA sequence, the chromosomal localization and the tissue expression
of an additional subunit, the B17 subunit. The cDNA open reading frame of B17
comprises 387 bp and encodes a protein of 128 amino acids (calculated Mr 15.5
kDa). There is 82.7% and 78.1% homology, respectively, at the cDNA and amino acid
level with the bovine counterpart. The gene of the B17 subunit has been mapped to
chromosome 2. Multiple-tissue dot-blots showed ubiquitous expression of the mRNA
with relatively higher expression in tissues known for their high energy demand.
Of these, kidney showed the highest expression. Mutational analysis of the
subunit revealed no mutations or polymorphisms in 20 patients with isolated
enzymatic complex I deficiency in cultured skin fibroblasts.
PMID- 9760211
TI - Genotype/phenotype correlation in affected individuals of a family with a
deletion of the entire coding sequence of the connexin 32 gene.
AB - X-linked Charcot-Marie-Tooth disease (CMTX) is a peripheral nerve disorder that
has been linked to mutations in the connexin 32 gene (Cx32). These mutations have
been shown to be genetically heterogeneous, though recurrences of specific
mutations in apparently unrelated families have been seen. The majority of
mutations have been shown to be missense, resulting in non-conservative amino
acid changes. A few mutations resulting in a premature termination of protein
translation, including both nonsense mutations as well as frameshifting
microdeletions, have been documented. We would like to report a deletion mutation
that appears to eliminate the entire coding sequence of the Cx32 gene, but which
has been shown to segregate with a clinical phenotype not unlike that seen in
individuals with a less severe alteration of the Cx32 gene. The causes at a
cellular level of the CMTX phenotype are still not fully clear, though there has
been speculation that these may involve a dominant negative effect where the
mutant connexin 32 suppresses the function of other connexins. Studies of
kindreds such as this, where in CMTX-affected males the Cx32 gene product is
totally absent, will help us to better understand the molecular mechanisms
underlying the clinical phenotype associated with this disorder.
PMID- 9760213
TI - The last 25 years -- the most highly cited papers.
PMID- 9760214
TI - From absolute to exquisite specificity. Reflections on the fuzzy nature of
species, specificity and antigenic sites.
AB - The term specificity is derived from the word species and shares with it an
inherent fuzziness based on the absence of sharp boundaries between closely
related entities. Antibody specificity is a ternary relational property which
refers to the antibody's capacity to discriminate between two or more epitopes.
There are no sharp boundaries between the individual overlapping epitopes that
constitute an antigenic site and there is also no clear-cut minimum difference in
binding affinity or in atomic positions at the epitope-paratope interface that
can serve as a yardstick for deciding that two epitopes or two paratopes are the
same or not. Immunology shares with the whole of empirical science the need to
handle fuzzy sets and concepts and this poses no threat to the unabated further
development of immunochemical analysis.
PMID- 9760216
TI - Computational models in immunological methods: an historical review.
AB - The utilization of computational models in immunology dates from the birth of the
science. From the description of antibody-antigen binding to the structural
models of receptors, models are utilized to bring fundamental understandings of
the processes together with laboratory measurements to uncover implications of
these data. In this review, an historical view of the role of computational
models in the immunology laboratory is presented, and short mathematical
descriptions are given of fundamental assays. In addition, the range of current
uses of models is explored -- especially as seen through papers which have
appeared in the Journal of Immunological Methods from volume 1 (1971/1972) to
volume 208 (1997). Each paper which introduced a new mathematical, statistical,
or computer simulation model, or introduced an enhancement to an instrument
through a model in those volumes is cited and the type of computational model
noted.
PMID- 9760215
TI - The increasing power of immunohistochemistry and immunocytochemistry.
AB - Since its introduction in the early 1940s, immunostaining technology has
developed in a remarkable way, and the applicability of immunohisto/cytochemical
probing methods will unquestionably continue to increase in several directions.
Immunofluorescence remains the most powerful and reliable immunohistochemical
approach for multicolour staining to evaluate co-localization of two or more
antigens in an objective manner. Moreover, the fluorescent colour signals exhibit
a relatively consistent relationship to the actual antigen concentration in the
test preparation and are hence better suited for quantitative computerized image
analysis than light-microscopic observations of immunoenzyme staining. On the
other hand, immunoenzyme methods are more economical with regard to reagent
consumption and are therefore ideal for the use in semiautomatic staining
machines. In addition, the superior morphological correlate provided by the
latter methods, makes them more attractive and adequate for most purposes in
diagnostic pathology laboratories. However, multicolour immunoenzyme staining
provides an easily obtainable and reliable result only when the antigens are
known a priori to be separately located, both because of technical problems and
because imbalanced colour mixing is difficult to evaluate in the light
microscope. All these aspects of immunohistochemistry are briefly reviewed in
this historical perspective coloured by the author's own experience.
PMID- 9760217
TI - Developments in immunological standardization.
AB - In the century since Paul Erlich's innovative immunological standardization work
with diphtheria anti-toxin, the field of immunological standardization has
expanded dramatically. Biological standards for a diverse range of immunological
substances have been produced e.g. immunoglobulins, complement components,
autoantibodies and blood group reagents. The concept of calibration of such
materials in biological units of potency is now widely accepted for many such
substances. Most recently much effort has been devoted to producing biological
standards for cytokines which can be used to calibrate and validate biological
assays for these analytes. Immunoassays have been found to be particularly
problematical from the standardization view point although provision of a single
international standard for distribution world-wide is clearly advantageous and
helps reduce assay variability. It is hoped that the considerable progress with
immunological standardization achieved during the past century will continue and
expand to ensure the validity of existing and new immunological assays which will
be required in the future.
PMID- 9760218
TI - WHO cytokine standardization: facilitating the development of cytokines in
research, diagnosis and as therapeutic agents.
AB - The development and widespread application of recombinant DNA technology has
dramatically increased the number of cytokines available for clinical evaluation.
New and novel cytokines are being discovered, cloned and entered into clinical
trials at such a rate that it is often the case that the biological activities of
these proteins are poorly understood during their development as therapeutic
agents. In addition, manufacturers of any one cytokine can produce the protein
from different cellular sources resulting in materials that exhibit markedly
different specific activities. When estimating the amount of biological activity
of different preparations with different specific activities by bioassay, mass
units cannot be used and biological activity is therefore expressed as
'biological potency units'. The biological unit requires definition by a standard
that is assay-independent (especially when measuring a particular type of
biological activity). In many cases, a variety of assay methods will be available
and the material chosen for a standard should ideally be suitable for use with as
many of them as possible. Once the unit is defined, this can be used in any
laboratory, thus providing a means of ensuring uniformity throughout the world in
the designation of potency of different biological preparations. The World Health
Organisation (WHO) standardization programme involves the production of
biologically stable, well characterised potency and immunoassay standards that
are available world-wide using a single international unitage. Over the years,
WHO international standards have been used to dramatically reduce the variation
in estimates of cytokine preparations within and between laboratories for
immunoassays and bioassays. WHO international standards are primary reference
preparations against which secondary, or working standards (including regional
standards, national standards, pharmacopoeial standards and in-house working
standards) can be calibrated.
PMID- 9760219
TI - Self-reactive antibodies (natural autoantibodies) in healthy individuals.
AB - Antibodies that are present in the serum of healthy individuals in the absence of
deliberate immunization with any antigen, are refered to as natural antibodies. A
vast majority of natural antibodies react with one or more self antigens and are
termed as natural autoantibodies. The importance of natural autoantibodies in
immune regulation has long been neglected, since tolerance to self was thought to
be primarily dependent on the deletion of autoreactive clones, rather than on
peripheral suppressive mechanisms. Clonal deletion and energy cannot account,
however, for the prevalence of natural autoreactivity among healthy individuals.
It is now well established that autoreactive antibodies and B cells, and
autoreactive T cells, are present in healthy individuals, and in virtually all
vertebrate species. Autoreactive repertoires are predominantly selected early in
ontogeny. Questions pertaining to the role of natural antibodies in the
regulation of the immune response and maintenance of immune homeostasis and to
the distinction between natural autoreactivity and pathological autoimmunity have
not been adequately addressed. Here, we focus on the current knowledge on the
physicochemical and functional properties of NAA in man, and the use of NAA for
therapeutic intervention. reserved.
PMID- 9760221
TI - Use of explant technology in the study of in vitro immune responses.
AB - The establishment of in vitro culture systems provides an accessible means to
study events within the immune system. In contrast to either dispersed suspension
or two-dimensional monolayer culture, the explantation of tissue fragments under
organ culture conditions is, to date, the only method which allows essential
three-dimensional cellular interactions to be maintained under conditions which
permit controlled experimental manipulation in vitro. Recent modifications of
explant technology, particularly within the area of fetal thymic organ culture,
now allow the controlled reassociation of defined cellular subsets and
manipulation of gene expression, under conditions where the functioning of both
lymphoid and stromal cell types closely resembles that in vivo.
PMID- 9760220
TI - Assays of leukocyte locomotion and chemotaxis.
AB - This review discusses the range of methods which are currently available for
measuring locomotion and chemotaxis of leukocytes in vitro, their history, and
some definitions of terms. Assays of the net migration of large cell populations,
such as the filter assay are the most popular and are useful for identifying
chemoattractant molecules, but give no direct information about how these
molecules influence the speed and direction of cell movement (chemokinesis and
chemotaxis). Visual assays including measures of orientation in gradients and
time-lapse filming give detailed information about cell paths and direct evidence
for chemotaxis and chemokinesis. The polarization assay is a useful visual
screening assay. Assays which simulate the situation in living tissues are
becoming more popular and include migration through collagen or fibrin gels or
through monolayers of vascular endothelium. Locomotion is a complex process, no
single assay gives full information and the use of more than one assay is
recommended.
PMID- 9760222
TI - Antibody engineering: comparison of bacterial, yeast, insect and mammalian
expression systems.
AB - Engineered antibody molecules, and their fragments, are being increasingly
exploited as scientific and clinical tools. However, one factor that can limit
the applicability of this technology is the ability to express large amounts of
active protein. In this review we describe the relative advantages and
disadvantages of bacterial, yeast, insect and mammalian expression systems, and
discuss some of the problems that can be encountered when using them. There is no
'universal' expression system, that can guarantee high yields of recombinant
product, as every antibody-based molecule will pose its own problems in terms of
expression. As a result the choice of system will depend on many factors,
including the molecular species being expressed, the precise sequence of the
individual antibody and the preferences of the individual investigator. However,
there are general rules with regards to the design of expression vectors and
systems which will help the investigator to make informed choices as to which
strategy might be appropriate for their application.
PMID- 9760223
TI - Recommendations for prevention and control of tuberculosis among foreign-born
persons. Report of the Working Group on Tuberculosis among Foreign-Born Persons.
Centers for Disease Control and Prevention.
AB - During 1986-1997, the number of tuberculosis (TB) cases among foreign-born
persons in the United States increased by 56%, from 4,925 cases (22% of the
national total) to 7,702 cases (39% of the national total). As the percentage of
reported TB cases among foreign-born persons continues to increase, the
elimination of TB in the United States will depend increasingly on the
elimination of TB among foreign-born persons. On May 16-17, 1997, CDC convened a
working group of state and city TB-control program staff, as well as
representatives from CDC's Division of TB Elimination and Division of Quarantine,
to outline problems and propose solutions for addressing TB among foreign-born
persons. The Working Group on Tuberculosis Among Foreign-Born Persons considered
a) epidemiologic profiles of TB cases among foreign-born persons, b) case
finding, screening, and preventive therapy for the foreign born, c) TB diagnosis
and management for the foreign born, d) opportunities for collaborations with
community-based organizations (CBOs) to address TB among the foreign born, and e)
TB-related training needs. The Working Group's deliberations and the resulting
recommendations for action by federal agencies, state and local TB-control
programs, CBOs, and private health-care providers form the basis of this report.
For each of the five topics of discussion, the group identified key issues,
problems, and constraints and suggested solutions in the form of recommendations,
which are detailed in this report. The Working Group made the following
recommendations: * The epidemiology of TB among foreign-born populations differs
considerably from area to area. To tailor TB-control efforts to local needs, TB
control programs should develop epidemiologic profiles to identify groups of
foreign-born persons in their jurisdictions who are at high risk for TB. * The
priorities of TB control among the foreign born should be the same as those for
control of TB among other U.S. populations - completion of treatment by persons
infected with active TB, contact tracing, and screening and provision of
preventive therapy for groups at high risk. Screening and preventive therapy
should be limited to areas where completion of therapy rates and contact-tracing
activities are currently adequate. * Based on local epidemiologic profiles,
selective screening should be conducted among populations identified as being at
high risk for TB. Screening should target groups of persons who are at the
highest risk for TB infection and disease, accessible for screening, and likely
to complete preventive therapy. The decision to screen for infection, disease, or
both should be based on the person's age and time in the United States, prior
screening, and locally available resources for the provision of preventive
therapy. * TB-control programs should direct efforts towards identifying
impediments to TB diagnosis and care among local foreign-born populations,
devising strategies to address these barriers, and maximizing activities to
ensure completion of treatment. * Providing TB preventive therapy and other TB
related services for foreign-born persons is often impeded by linguistic,
cultural, and health-services barriers. TB-control programs can help overcome
these barriers by establishing partnerships with CBOs and by strengthening
training and education efforts. Collaborations with health-service CBOs should
center on developing more complementary roles, more effective coordination of
services, and better use of existing resources for serving the foreign born. TB
related training should be linked to overall TB-control strategies for the
foreign born. Training and education should be targeted to providers, patients,
and community workers.
PMID- 9760224
TI - Bernstein's dynamic view of the brain: the current problems of modern
neurophysiology (1945).
PMID- 9760225
TI - Crystal structure and possible dimerization of the high-potential iron-sulfur
protein from Chromatium purpuratum.
AB - The crystal structure of the high-potential iron-sulfur protein (HiPIP) isolated
from Chromatium purpuratum is reported at 2.7 A resolution. The three HiPIP
molecules in the asymmetric unit of the crystals form one and one-half dimers.
Two molecules are related by a noncrystallographic symmetry rotation of
approximately 175 degrees with negligible translation along the dyad axis. The
third molecule in the asymmetric unit also forms a dimer with a second HiPIP
molecule across the crystallographic 2-fold symmetry axis. The Fe4S4 clusters in
both the crystallographic and noncrystallographic dimers are separated by
approximately 13.0 A. Solution studies give mixed results regarding the
oligomeric state of the C. purpuratum HiPIP. A comparison with crystal structures
of HiPIPs from other species shows that HiPIP tends to associate rather
nonspecifically about a conserved, relatively hydrophobic surface patch to form
dimers.
PMID- 9760226
TI - Possible arrangement of the five domains in human complement factor I as
determined by a combination of X-ray and neutron scattering and homology
modeling.
AB - Human factor I is a multidomain plasma serine protease with one factor I-membrane
attack complex (FIMAC) domain, one CD5 domain, two low-density lipoprotein
receptor (LDLr) domains, and one serine protease (SP) domain and is essential for
the regulation of complement. The domain arrangement in factor I was determined
by X-ray and neutron scattering on serum-derived human factor I (sFI) and
recombinant insect cell factor I (rFI). While the radii of gyration of both were
the same at 4.05 nm and both had overall lengths of 14 nm, the cross-sectional
radii of gyration were different at 1.70 nm for sFI and 1.57 nm for rFI. This
difference was attributed to their different means of glycosylation which is
complex-type for sFI and high-mannose-type for rFI. Homology models were
constructed for the FIMAC, LDLr, and SP domains of factor I using related crystal
structures, and CD5 was represented as a globular protein by referencing its
electron microscopy dimensions. In these models, 38 of the 40 Cys residues in
factor I were predicted to form internal disulfide bridges. The two remaining Cys
residues at the N terminus of the FIMAC domain and at the center of the first
LDLr domain were potentially not bridged. It was postulated that, if these two
Cys residues were bridged to each other, the FIMAC, CD5, and LDLr-1 domains would
form a compact triangular arrangement. This hypothesis was tested by automated
scattering curve fit searches based on 9600 bilobal models, setting the FIMAC,
CD5, and LDLr-1 domains as one lobe and the large SP domain as the other lobe.
The searches gave a single small family of similar structures with a separation
of 5.9 nm between the centers of the lobes which gave similar good X-ray and
neutron fits for both sFI and rFI, despite the different glycosylations of sFI
and rFI. These best-fit structures for factor I showed that this domain model is
plausible, and suggested that the SP and the CD5 and LDLr-1 domains may present
exposed surfaces in factor I whose roles are to interact separately with its
substrates C3b and C4b and with cofactor proteins.
PMID- 9760228
TI - Residues critical for formylglycine formation and/or catalytic activity of
arylsulfatase A.
AB - Sulfatases contain a unique posttranslational modification in their active site,
a formylglycine residue generated from a cysteine or a serine residue. The
formylglycine residue is part of a sequence that is highly conserved among
sulfatases, suggesting that it might direct the generation of this unique amino
acid derivative. In the present study residues 68-86 flanking formylglycine 69 in
arylsulfatase A were subjected to an alanine/glycine scanning mutagenesis. The
mutants were analyzed for the conversion of cysteine 69 to formylglycine and
their kinetic properties. Only cysteine 69 turned out to be essential for
formation of the formylglycine residue, while substitution of leucine 68, proline
71, and alanine 74 within the heptapeptide LCTPSRA reduced the formylglycine
formation to about 30-50%. Several residues that are part of or directly adjacent
to an alpha-helix presenting the formylglycine 69 at the bottom of the active
site pocket were found to be critical for catalysis. A surprising outcome of this
study was that a number of residues fully or highly conserved between all known
eukaryotic and prokaryotic sulfatases turned out to be essential neither for
generation of formylglycine nor for catalysis.
PMID- 9760227
TI - Structural basis for the recognition of carbohydrates by human galectin-7.
AB - Knowledge about carbohydrate recognition domains of galectins, formerly known as
S-type animal lectins, is important in understanding their role(s) in cell-cell
interactions. Here we report the crystal structure of human galectin-7 (hGal-7),
in free form and in the presence of galactose, galactosamine, lactose, and N
acetyl-lactosamine at high resolution. This is the first structure of a galectin
determined in both free and carbohydrate-bound forms. The structure shows a fold
similar to that of the prototype galectins -1 and -2, but has greater similarity
to a related galectin molecule, Gal-10. Even though the carbohydrate-binding
residues are conserved, there are significant changes in this pocket due to
shortening of a loop structure. The monomeric hGal-7 molecule exists as a dimer
in the crystals, but adopts a packing arrangement considerably different from
that of Gal-1 and Gal-2, which has implications for carbohydrate recognition.
PMID- 9760229
TI - Exploring a channel to the active site of copper/topaquinone-containing
phenylethylamine oxidase by chemical modification and site-specific mutagenesis.
AB - Copper amine oxidase contains an organic redox cofactor, 2,4, 5
trihydroxyphenylalaninequinone (topaquinone, TPQ), derived by the post
translational modification of a specific tyrosyl residue. To identify amino acid
residues participating in the biogenesis of TPQ in the recombinant
phenylethylamine oxidase from Arthrobacter globiformis, we have modified the
copper/TPQ-less apoenzyme and the copper/TPQ-containing holoenzyme with 4-fluoro
7-nitrobenzo-2-oxa-1, 3-diazole (NBD-F). In the apoenzyme modification, the Cu2+
dependent, self-processing formation of the TPQ cofactor was retarded in
accordance with the amount of NBD incorporated. The holoenzyme was also rapidly
inactivated by incubation with NBD-F. The inactivation was prevented almost
completely in the presence of an oxidation product from phenylethylamine,
phenylacetaldehyde. Furthermore, the reaction of an inhibitor, phenylhydrazine,
with TPQ was much slower in the NBD-labeled holoenzyme than in the native
holoenzyme. Sequence analysis of the NBD-labeled holoenzyme has identified Lys184
and Lys354 as the labeled sites. The two Lys residues are located close to the
entrance to a channel, which has been found by recent X-ray crystallographic
studies to be suitable for the movement of substrates and products to and from
the Cu2+/TPQ-active site buried in the protein interior (Wilce, M. C. J., et al.
(1997) Biochemistry 36, 16116-16133). However, site-specific mutant enzymes for
Lys184, Lys354, and the neighboring invariant His355 had normal capacities for
the TPQ formation in apoenzyme. These residues were also found to be dispensable
for catalytic activity of holoenzyme. Thus, modification of Lys184 and Lys354
with NBD-F presumably causes structural perturbations of the substrate channel or
steric hindrance for the access of small molecules to the active site through the
channel.
PMID- 9760230
TI - Nucleoside diphosphate kinase from bovine retina: purification, subcellular
localization, molecular cloning, and three-dimensional structure.
AB - The biochemical and structural properties of bovine retinal nucleoside
diphosphate kinase were investigated. The enzyme showed two polypeptides of
approximately 17.5 and 18.5 kDa on SDS-PAGE, while isoelectric focusing revealed
seven to eight proteins with a pI range of 7.4-8.2. Sedimentation equilibrium
yielded a molecular mass of 96 +/- 2 kDa for the enzyme. Carbohydrate analysis
revealed that both polypeptides contained Gal, Man, GlcNAc, Fuc, and GalNac
saccharides. Like other nucleoside diphosphate kinases, the retinal enzyme showed
substantial differences in the Km values for various di- and triphosphate
nucleotides. Immunogold labeling of bovine retina revealed that the enzyme is
localized on both the membranes and in the cytoplasm. Screening of a retinal cDNA
library yielded full-length clones encoding two distinct isoforms (NBR-A and NBR
B). Both isoforms were overexpressed in Escherichia coli and their biochemical
properties compared with retinal NDP-kinase. The structures of NBR-A and NBR-B
were determined by X-ray crystallography in the presence of guanine
nucleotide(s). Both isoforms are hexameric, and the fold of the monomer is
similar to other nucleoside diphosphate kinase structures. The NBR-A active site
contained both a cGMP and a GDP molecule each bound at half occupancy while the
NBR-B active site contained only cGMP.
PMID- 9760231
TI - Role of active site tyrosine residues in catalysis by human glutathione
reductase.
AB - Tyr114 and Tyr197 are highly conserved residues in the active site of human
glutathione reductase, Tyr114 in the glutathione disulfide (GSSG) binding site
and Tyr197 in the NADPH site. Mutation of either residue has profound effects on
catalysis. Y197S and Y114L have 17% and 14% the activity of the wild-type enzyme,
respectively. Mutation of Tyr197, in the NADPH site, leads to a decrease in Km
for GSSG, and mutation of Tyr114, in the GSSG site, leads to a decrease in Km for
NADPH. This behavior is predicted for enzymes operating by a ping-pong mechanism
where both half-reactions partially limit turnover. Titration of the wild-type
enzyme or Y114L with NADPH proceeds in two phases, Eox to EH2 and EH2 to EH2
NADPH. In contrast, Y197S reacts monophasically, showing that excess NADPH fails
to enhance the absorbance of the thiolate-FAD charge-transfer complex, the
predominant EH2 form of glutathione reductase. The reductive half-reactions of
the wild-type enzyme and of Y114L are similar; FAD reduction is fast
(approximately 500 s-1 at 4 degreesC) and thiolate-FAD charge-transfer complex
formation has a rate of 100 s-1. In Y197S, these rates are only 78 and 5 s-1,
respectively. The oxidative half-reaction, the rate of reoxidation of EH2 by
GSSG, of the wild-type enzyme is approximately 4-fold faster than that of Y114L.
These results are consistent with Tyr197 serving as a gate in the binding of
NADPH, and they indicate that Tyr114 assists the acid catalyst His467'.
PMID- 9760233
TI - Conformational changes occurring upon reduction and NO binding in nitrite
reductase from Pseudomonas aeruginosa.
AB - Nitrite reductase (NiR) from Pseudomonas aeruginosa (EC 1.9.3.2) (NiR-Pa) is a
soluble enzyme catalyzing the reduction of nitrite (NO2-) to nitric oxide (NO).
The enzyme is a 120 kDa homodimer, in which each monomer carries one c and one d1
heme. The oxidized and reduced forms of NiR from Paracoccus denitrificans GB17
(previously called Thiosphaera pantotropha) (NiR-Pd) have been described [Fulop,
V., et al. (1995) Cell 81, 369-377; Williams, P. A., et al. (1997) Nature 389,
406-412], and we recently reported on the structure of oxidized NiR-Pa at 2.15 A
[Nurizzo, D., et al. (1997) Structure 5, 1157-1171]. Although the domains
carrying the d1 heme are almost identical in both NiR-Pa and NiR-Pd oxidized and
reduced structures, the c heme domains show a different pattern of c heme
coordination, depending on the species and the redox state. The sixth d1 heme
ligand in oxidized NiR-Pd was found to be Tyr25, whereas in NiR-Pa, the
homologuous Tyr10 does not interact directly with Fe3+, but via a hydroxide ion.
Furthermore, upon reduction, the axial ligand of the c heme of NiR-Pd changes
from His17 to Met108. Finally, in the oxidized NiR-Pa structure, the N-terminal
stretch of residues (1-29) of one monomer interacts with the other monomer
(domain swapping), which does not occur in NiR-Pd. Here the structure of reduced
NiR-Pa is described both in the unbound form and with the physiological product,
NO, bound at the d1 heme active site. Although both structures are similar to
that of reduced NiR-Pd, significant differences with respect to oxidized NiR-Pd
were observed in two regions: (i) a loop in the c heme domain (residues 56-62) is
shifted 6 A away and (ii) the hydroxide ion, which is the sixth coordination
ligand of the heme, is removed upon reduction and NO binding and the Tyr10 side
chain rotates away from the position adopted in the oxidized form. The
conformational changes observed in NiR-Pa as the result of reduction are less
extensive than those occurring in NiR-Pd. Starting with oxidized structures that
differ in many respects, the two enzymes converge, yielding reduced conformations
which are very similar to each other, which indicates that the conformational
changes involved in catalysis are considerably diverse.
PMID- 9760232
TI - Ligand-induced conformational change in transferrins: crystal structure of the
open form of the N-terminal half-molecule of human transferrin.
AB - Serum transferrin binds ferric ions in the bloodstream and transports them to
cells, where they are released in a process involving receptor-mediated
endocytosis. Iron release is believed to be pH dependent and is coupled with a
large conformational change. To help define the steps in iron release, we have
determined the three-dimensional structure of the iron-free (apo) form of the
recombinant N-lobe half-molecule of human serum transferrin (ApoTfN) by X-ray
crystallography. Two crystal forms were obtained, form 1 with four molecules in
the asymmetric unit and form 2 with two molecules in the asymmetric unit. The
structures of both forms were determined by molecular replacement and were
refined at 2.2 and 3.2 A resolution, respectively. Final R-factors were 0.203
(free R = 0. 292) for form 1 and 0.217 (free R = 0.312) for form 2. All six
copies of the ApoTfN structure are essentially identical. Comparison with the
holo form (FeTfN) shows that a large rigid-body domain movement of 63 degrees has
occurred in ApoTfN, to give an open binding cleft. The extent of domain opening
is the same as in the N-lobe of human lactoferrin, showing that it depends on
internal constraints that are conserved in both proteins, and that it is
unaffected by the presence or absence of the C-lobe. Although the conformational
change is primarily a rigid-body motion, several local adjustments occur. In
particular, two iron ligands, Asp 63 and His 249, change conformation to form
salt bridges, with Lys 296 and Glu 83, respectively, in the binding cleft of the
apo protein. Both salt bridges would have to break for iron coordination to
occur. Most importantly, the structure, determined at a pH (5.3) that is close to
the pH of physiological iron release, indicates that protonation of His 249 is a
key step in iron release.
PMID- 9760234
TI - Neutron-scattering studies reveal further details of the Ca2+/calmodulin
dependent activation mechanism of myosin light chain kinase.
AB - Previously, we utilized small-angle X-ray scattering and neutron scattering with
contrast variation to obtain the first low-resolution structure of
4Ca2+.calmodulin (CaM) complexed with a functional enzyme, an enzymatically
active truncation mutant of skeletal muscle myosin light chain kinase (MLCK).
These experiments showed that, upon binding to MLCK, CaM undergoes a
conformational collapse identical to that observed when CaM binds to the isolated
peptide corresponding to the CaM binding sequence of MLCK. CaM thereby was shown
to release the inhibition of the kinase by inducing a significant movement of its
CaM binding and autoinhibitory sequences away from the surface of the catalytic
core [Krueger, J. K., Olah, G. A., Rokop, S. E., Zhi, G., Stull, J. T., and
Trewhella, J. (1997) Biochemistry 36, 6017-6023]. We report here similar
scattering experiments on the CaM.MLCK complex with the addition of substrates; a
nonhydrolyzable analogue of adenosine-triphosphate, AMPPNP, and a peptide
substrate for MLCK, a phosphorylation sequence from myosin regulatory light chain
(pRLC). These substrates are shown to induce an overall compaction of the
complex. The separation of the centers-of-mass of the CaM and MLCK components is
shortened (by approximately 12 A), thus bringing CaM closer to the catalytic site
compared to the complex without substrates. In addition, there appears to be a
reorientation of CaM with respect to the kinase upon substrate binding that
results in interactions between the N-terminal sequence of CaM and the kinase
that were not observed in the complex without substrates. Finally, the kinase
itself becomes more compact in the CaM.MLCK.pRLC.AMPPNP complex compared to the
complex without substrates. This observed compaction of MLCK upon substrate
binding is similar to that arising from the closure of the catalytic cleft in
cAMP-dependent protein kinase upon binding pseudosubstrate.
PMID- 9760235
TI - Mapping substrate-induced conformational changes in cAMP-dependent protein kinase
by protein footprinting.
AB - Upon binding of substrates the catalytic subunit (C) of cAMP-dependent protein
kinase (cAPK) undergoes significant induced conformational changes that lead to
catalysis. For the free apoenzyme equilibrium favors a more open and malleable
conformation while the ternary complex of C, MgATP, and a 20-residue inhibitor
peptide [PKI (5-24)] adopts a tight and closed conformation [Zheng, J., et al.
(1993) Protein Sci. 2, 1559]. It is not clear that binding of either ligand alone
is responsible for this conformational switch or whether both are required. In
addition, the catalytic subunit binds MgATP and inhibitor peptide
synergistically. The structural basis for this synergism is also not defined at
present. Using an Fe-EDTA-mediated protein footprinting technique, the
conformational changes associated with the binding of MgATP and the heat stable
protein kinase inhibitor (PKI) were probed by mapping the solvent-accessible
surface and structural dynamics of C. The conformation of the free enzyme was
clearly distinguished from the ternary complex. Furthermore, binding of MgATP
alone induced extensive conformational changes, both local and global, that
include the glycine-rich loop, the linker connecting the small and large lobes,
the catalytic loop, the Mg2+ positioning loop, the activation loop, and the F
helix. These changes, similar to those seen in the ternary complex, are
consistent with a transition from an open to a more closed conformation and
likely reflect the motions that are associated with catalysis and product
release. In contrast, the footprinting pattern of C.PKI resembled free C,
indicating minimal conformational changes. Binding of MgATP, by shifting the
equilibrium to a more closed conformation, "primes" the enzyme so that it is
poised for the docking of PKI and provides an explanation for synergism between
MgATP and PKI.
PMID- 9760236
TI - Structural basis of the Tanford transition of bovine beta-lactoglobulin.
AB - The structures of the trigonal crystal form of bovine beta-lactoglobulin variant
A at pH 6.2, 7.1, and 8.2 have been determined by X-ray diffraction methods at a
resolution of 2.56, 2. 24, and 2.49 A, respectively. The corresponding values for
R (Rfree) are 0.192 (0.240), 0.234 (0.279), and 0.232 (0.277). The C and N
termini as well as two disulfide bonds are clearly defined in these models. The
glutamate side chain of residue 89 is buried at pH 6.2 and becomes exposed at pH
7.1 and 8.2. This conformational change, involving the loop 85-90, provides a
structural basis for a variety of pH-dependent chemical, physical, and
spectroscopic phenomena, collectively known as the Tanford transition.
PMID- 9760237
TI - Anionic binding site and 2,3-DPG effect in bovine hemoglobin.
AB - It is generally believed that bovine hemoglobin (BvHb) interacts weakly with 2,3
diphosphoglycerate (2,3-DPG) in a chloride-free media and not at all in the
presence of physiological concentrations of chloride (100 mM). This lack of
interaction has raised several questions at both structural and evolutionary
levels. Results obtained in this study via 31P nuclear magnetic resonance (NMR)
show that, even in the presence of 100 mM chloride ions, 2,3-DPG does, in fact,
interact with bovine deoxy-Hb. This spectroscopic observation has been confirmed
by oxygen binding experiments, which have also shown that, under certain
conditions, chloride and 2,3-DPG may display a synergistic effect in modifying
the oxygen affinity of bovine hemoglobin. It could be that this synergistic
effect has its structural basis in a conformational modification induced by 2,3
DPG, possibly causing extra chloride anions to approach the positive charges
which constitute the anion binding site. Another possibility, not necessarily an
alternative, is the additional chloride binding site recently identified
[Fronticelli, C., Sanna, M. T., Perez-Alvarado, G. C., Karavitis, M., Lu, A.-L.,
and Brinnigar, W. S. (1995) J. Biol. Chem 270, 30588-30592] involving lysine
beta76 that in bovine Hb substitutes for the alanine residue present in human
hemoglobin. All of these findings are in agreement with the very low enthalpy of
oxygenation that characterizes bovine Hb when both chloride and 2,3-DPG are
present in concomitance. The results reported here clearly show that bovine
hemoglobin does react with 2, 3-DPG and is functionally affected by this organic
phosphate. Hence, the very low intraerythrocytic concentration of 2,3-DPG (0.5
mM) in adult bovine red blood cells is the result of metabolic adaptation which
cannot be explained solely by the different amino acid sequence at the level of
the 2,3-DPG binding site.
PMID- 9760238
TI - Identification of the binding surface on Cdc42Hs for p21-activated kinase.
AB - The Ras superfamily of GTP-binding proteins is involved in a number of cellular
signaling events including, but not limited to, tumorigenesis, intracellular
trafficking, and cytoskeletal organization. The Rho subfamily, of which Cdc42Hs
is a member, is involved in cell morphogenesis through a GTPase cascade which
regulates cytoskeletal changes. Cdc42Hs has been shown to stimulate DNA synthesis
as well as to initiate a protein kinase cascade that begins with the activation
of the p21-activated serine/threonine kinases (PAKs). We have determined
previously the solution structure of Cdc42Hs [Feltham et al. (1997) Biochemistry
36, 8755-8766] using NMR spectroscopy. A minimal-binding domain of 46 amino acids
of PAK was identified (PBD46), which binds Cdc42Hs with a KD of approximately 20
nM and inhibits GTP hydrolysis. The binding interface was mapped by producing a
fully deuterated sample of 15N-Cdc42Hs bound to PBD46. A 1H,15N-NOESY-HSQC
spectrum demonstrated that the binding surface on Cdc42Hs consists of the second
beta-strand (beta2) and a portion of the loop between the first alpha-helix
(alpha1) and beta2 (switch I). A complex of PBD46 bound to 15N-Cdc42Hs.GMPPCP
exhibited extensive chemical shift changes in the 1H,15N-HSQC spectrum. Thus,
PBD46 likely produces structural changes in Cdc42Hs which are not limited to the
binding interface, consistent with its effects on GTP hydrolysis. These results
suggest that the kinase-binding domain on Cdc42Hs is similar to, but more
extensive than, the c-Raf-binding domain on the Ras antagonist, Rap1 [Nassar et
al. (1995) Nature 375, 554-560)].
PMID- 9760239
TI - Activation of methylesterase CheB: evidence of a dual role for the regulatory
domain.
AB - The response regulator CheB functions within the bacterial chemotaxis system
together with the methyltransferase CheR to control the level of chemoreceptor
methylation, influencing the signaling activities of the receptors. CheB
catalyzes demethylation of specific methylglutamate residues introduced into the
chemoreceptors by CheR. CheB has a two-domain architecture consisting of an N
terminal regulatory domain joined by a linker to a C-terminal effector domain. In
the unphosphorylated state of the response regulator, the regulatory domain
inhibits the methylesterase activity of the effector domain. Upon phosphorylation
of a specific aspartate residue within the regulatory domain, the C-terminal
methylesterase activity is stimulated, resulting in the subsequent demethylation
of the chemoreceptors. We have investigated the mechanism of regulation of CheB
activity by the N-terminal regulatory domain. First, we have found that
phosphorylation of the N-terminal domain not only relieves inhibition of the C
terminal methylesterase activity but also provides an enhancement of this
activity above that seen for the C-terminal effector domain alone. Second, we
have identified mutations in CheB that show an enhancement of methylesterase
activity in the absence of phosphorylation. Most of these single-site mutations
are localized in the linker region joining the regulatory and effector domains.
On the basis of these observations, we propose a model for activation of CheB in
which phosphorylation of the regulatory domain results in a reorganization of the
domain interface, allowing exposure of the active site to the receptor substrate
and simultaneously stimulating methylesterase activity.
PMID- 9760240
TI - Solution structure of the catalytic domain of human stromelysin-1 complexed to a
potent, nonpeptidic inhibitor.
AB - The full three-dimensional structure of the catalytic domain of human stromelysin
1 (SCD) complexed to a novel and potent, nonpeptidic inhibitor has been
determined by nuclear magnetic resonance spectroscopy (NMR). To accurately mimic
assay conditions, the structure was obtained in Tris buffer at pH 6.8 and without
the presence of organic solvent. The results showed that the major site of enzyme
inhibitor interaction occurs in the S1' pocket whereas portions of the inhibitor
that occupy the shallow S2' and S1 pockets remained primarily solvent exposed.
Because this relatively small inhibitor could not deeply penetrate stromelysin's
long narrow hydrophobic S1' pocket, the enzyme was found to adopt a dramatic fold
in the loop region spanning residues 221-231, allowing occupation of the solvent
accessible S1' channel by the enzyme itself. This remarkable conformational fold
at the enzyme binding site resulted in constriction of the S1' loop region about
the inhibitor. Examination of the tertiary structure of the stromelysin-inhibitor
complex revealed few hydrogen-bonding or hydrophobic interactions between the
inhibitor and enzyme that can contribute to overall binding energy; hence the
resultant compact structure may in part account for the relatively high potency
exhibited by this inhibitor.
PMID- 9760241
TI - Site-directed mutants of rat testis fructose 6-phosphate, 2-kinase/fructose 2,6
bisphosphatase: localization of conformational alterations induced by ligand
binding.
AB - Site-directed mutagenesis was utilized to construct mutants, containing one or
two tryptophan residues, of the bifunctional enzyme fructose 6-phosphate,2-kinase
fructose 2,6-bisphosphatase. Two of the single-tryptophan mutants (W15 and W64)
had the tryptophan residue located in the kinase domain, which is in the N
terminal half, and two (W299 and W320) had the tryptophan residue located in the
phosphatase domain, which is in the C-terminal half. The double-tryptophan
mutants were W15/W64, W15/W299, W64/W299, and W299/W320. Dynamic polarization
data indicated that these tryptophan residues had varying degrees of local
mobility. Steady-state polarization data revealed energy transfer between the
tryptophan residues in the double mutant W299/W320 but not in the W15/W64,
W15/W299, or W64/W299 mutants, indicating the proximity of the W299 and W320
residues. The binding of fructose-6-phosphate resulted in a significant increase
in the anisotropy of the W15 mutants, but did not affect the anisotropies of any
of the other single-tryptophan mutants. Binding of fructose-2,6-bisphosphate also
significantly increased the anisotropy of W15. In the case of fructose-6
phosphate binding, the increased anisotropy was shown to be due to a restriction
of the tryptophan residue's local mobility in the presence of bound ligand, which
suggests that the N-terminus is located near the kinase active site. These
increases in anisotropies were used to estimate the dissociation constants of
fructose-6-phosphate and fructose-2,6-bisphosphate, which were 29 +/- 3 and 2.1
+/- 0.3 microM, respectively. These observations are considered in light of the
recently published crystal structure for this bifunctional enzyme.
PMID- 9760242
TI - The enzymatic properties of Octopus vulgaris hemocyanin: o-diphenol oxidase
activity.
AB - Hemocyanin and tyrosinase are dinuclear copper proteins capable of reversibly
binding dioxygen. Despite the great similarity of structure and properties of
their active site, the two proteins perform different biological functions
(oxygen transport/storage versus monooxygenase and oxidase activity). In this
paper, we show that Octopus vulgaris hemocyanin exhibits a tyrosinase-like
activity; namely, it is capable of utilizing dioxygen for the oxidation of o
diphenol to quinone. The reaction is specific for this isomer of diphenol, the
meta and para isomers being unreactive, and is strongly controlled by steric
factors. Dioxygen represents a cosubstrate of the reaction, and it is involved in
the catalytic turnover by binding to the dinuclear copper site of the protein to
form, under steady-state conditions, oxy-Hc, which is the active species. The
generation of semiquinone radicals, detected by EPR and by their reaction with
N,N,N',N'-tetramethyl-1,4-phenylenediamine, strongly supports a reaction
mechanism in which such radicals represent the reaction products of one-electron
oxidation of the substrate, quinone being generated by dismutation of
semiquinones. Met-Hc is regenerated by the substrate to the deoxy form. To close
the catalytic cycle, the proposed reaction mechanism also involves the
participation of two transient protein forms with the total oxidation state of
the active site (V and IV) intermediate between that of oxy-Hcy, [CuIIO22
CuII]VI, and deoxy-Hc, [CuICuI]II. A mathematical model has been elaborated to
describe the reaction kinetics. The differences in reaction mechanisms between
hemocyanin and tyrosinase are discussed in terms of accessibility to exogenous
molecules of their active sites.
PMID- 9760243
TI - Transactivation of the ApoCIII promoter by ATF-2 and repression by members of the
Jun family.
AB - It was shown previously that cytokines such as tumor necrosis factor-alpha that
stimulate signal transduction pathways involving transcription factors ATF-2 and
Jun repress apoCIII promoter activity in HepG2 cells. In the present study, DNase
I footprinting analysis established that ATF-2 protected three regions in the
apoCIII promoter. One region (-747/-726) present in the apoCIII enhancer is
within the previously identified footprint I and has overlapping boundaries with
the binding sites of Sp1 (-764/-742) and HNF-4 (-736/-714). The other two regions
represent new footprints and have been designated D/E (-219/-199) and B/C (-102/
75). The B/C region overlaps with the previously identified footprint B which
contains an HNF-4 binding site (-87/-63). Cotransfection experiments in HepG2
cells showed that ATF-2 transactivated the -890/+24 apoCIII promoter 1.6-fold. In
addition, mutations in the proximal D/E (-219/-199) and distal I (-747/-726) ATF
2-binding sites reduced the apoCIII promoter strength to 33 and 9% of control,
respectively, indicating that ATF-2 is a positive regulator of apoCIII gene
transcription. Cotransfections with ATF-2 and HNF-4 expression plasmids resulted
in additive transactivation of the apoCIII promoter. Furthermore, apoCIII
promoter constructs bearing mutations in the D/E and I ATF-2 binding sites were
efficiently transactivated by HNF-4, suggesting that these two factors contribute
independently to the apoCIII promoter strength. Members of the Jun family (c-Jun,
JunB, and JunD) caused a dose-dependent inhibition of the -890/+24 apoCIII
promoter activity. A synthetic promoter containing the apoCIII enhancer in front
of the minimal AdML promoter was also repressed by Jun. In contrast, apoCIII
promoter segments lacking the enhancer region were transactivated by Jun. The
findings suggest that homodimers of Jun or heterodimers of Jun with other AP-1
subunits could be responsible for the observed repression by interfering with the
function(s) of the apoCIII enhancer. Repression by Jun could be reversed in the
presence of ATF-2 and HNF-4, suggesting that ATF2 and possibly Jun/ATF-2
heterodimers exert a positive effect on apoCIII gene transcription, as opposed to
Jun homodimers or heterodimers with other AP-1 members. These findings suggest a
role for members of the Jun family and ATF-2 that participate in signal
transduction pathways in basal or induced apoCIII promoter activity in cells of
hepatic origin.
PMID- 9760244
TI - Photoaffinity labeling of homologous Met-133 and Met-139 amino acids of rabbit
and sheep sex hormone-binding globulins with the unsubstituted Delta 6
testosterone photoreagent.
AB - Purified rabbit and sheep sex hormone-binding globulins (SHBGs) were photolabeled
by Delta 6-testosterone. The maximal levels of specific incorporation were
respectively 0.33 and 0.30 mol of label/mol of homodimer. Tryptic cleavage of
photolabeled SHBGs gave a single radioactive peptide for rabbit SHBG and two
major radioactive peptides S1 and S2 for sheep SHBG. Edman sequencing of the
photolabeled peptide of rabbit SHBG revealed a single sequence corresponding to
peptidic fragment Leu-118-Lys-134. Subcleavage of this peptide with elastase led
to a single radioactive peptidic fragment corresponding to dipeptide Met-133-Lys
134, identified by mass spectrometry, while deletion of the C-terminal residue
with carboxypeptidase B showed that all the radioactivity remained on peptide Leu
118-Met-133, thus demonstrating that photolabeling occurred exclusively on Met
133, the only residue common to the two radioactive subcleaved peptides. Edman
sequencing of peptides S1 and S2 of sheep SHBG showed a same single sequence
corresponding to residues Gln-126-Arg-140 which contained no identifiable
phenylthiohydantoin derivative at cycle 14, thus indicating that in both cases
the corresponding Met-139 residue is the main site of photolabeling, as confirmed
for peptide S1 by the presence at this cycle of a major peak of radioactivity
while in peptide S2 the photoattachment of Delta 6-testosterone was found labile
in the conditions of sequencing. The photolabeled peptide S1 was characterized by
mass spectrometry which showed the covalent fixation of one mole of Delta 6
testosterone and the presence of a biantennary oligosaccharide attached at Asn
133, which suggests that the steroid-binding site is probably not deeply buried
in the SHBG homodimer.
PMID- 9760245
TI - The dimerization domain of potato spindle tuber viroid, a possible hallmark for
infectious RNA.
AB - Covalently closed circular (+) RNA of the potato spindle tuber viroid (PSTVd) can
efficiently dimerize noncovalently upon heating and slow cooling in the presence
of monovalent cations or Mg2+. In vitro transcription of subgenomic fragments
reveals that the ability to dimerize resides in the "upper strand" of its self
complementary rod-like structure. Nuclease probing of these fragments, namely,
molecules spanning either the upper or the lower strand of PSTVd, confirms the
existence of the previously proposed hairpins I-III, of which hairpin I might
contain noncanonical G.A and A.A base pairs. In addition, the upper and lower (+)
strands contain large hairpin loops consisting of stretches rich in either
adenosine or uridine. Dimerization of the upper (+) strand results in a nuclease
resistant core encompassing hairpin I and is inhibited by an antisense
oligonucleotide spanning the entire hairpin; this palindromic domain thus
represents the dimerization site. When upper and lower strands were heated and
cooled together, no annealing to a viroid-like duplex of both molecules occurs,
only dimerization of the upper strand. Therefore, the dimerization hairpin of
viroid RNA represents a unique conformational signal that is homologous to
similar regions in the human immunodeficiency virus and other retroviruses.
PMID- 9760246
TI - Structure and mucoadhesion of mussel glue protein in dilute solution.
AB - Purified mussel adhesive protein mefp-1 (Mytilus edulis foot protein 1) has been
studied regarding its state of oligomerization and gross conformation in dilute
solution. Sedimentation equilibrium in the analytical ultracentrifuge of a dilute
solution of protein (0.4 mg/mL) in acetate buffer at pH 4.5 and I = 0.10 M
yielded an apparent molecular weight (whole distribution weight average, Mw, app)
of 114 000 +/- 5000 via the "M" procedure, a value in almost exact agreement with
the monomeric molecular weight obtained by MALDI mass spectrometry. At this low
concentration, it is reasonable to assume thermodynamic ideality, i.e., Mw,app
approximately Mw. This result, together with plots of point weight average
apparent molecular weight versus concentration for three different loading
concentrations (0.4, 0.8, 1.0 mg/mL), clearly demonstrates that this protein is
essentially monomeric in dilute solution. Sedimentation velocity experiments
yielded an estimate of the sedimentation coefficient s020,w = 2.34 +/- 0.17 S,
which for M = 110 000 gives a frictional ratio f/f0 = 3.2 +/- 0.3. The
interpretation of this, in terms of an extended rather than globular conformation
for the structure of mefp-1 in dilute solution, is considered, within plausible
limits of molecular hydration, and models for the structure in solution are
considered, in light of the thermodynamic nonideality behavior of these molecules
and previously published circular dichroism data. The significance of these
observations in terms of the bioadhesive properties of mefp-1 is described, and
the very strong interaction in dilute solution with a mucin glycoprotein is
demonstrated.
PMID- 9760247
TI - The soluble granulocyte-macrophage colony-stimulating factor receptor's carboxyl
terminal domain mediates retention of the soluble receptor on the cell surface
through interaction with the granulocyte-macrophage colony-stimulating factor
receptor beta-subunit.
AB - The hematopoietic cytokine granulocyte-macrophage colony-stimulating factor (GM
CSF) mediates its activity through binding to cell-surface receptors. The high
affinity GM-CSF receptor (GMR) consists of two transmembrane-anchored subunits: a
ligand-specific, low-affinity subunit (GMRalpha); and a signal-transducing beta
subunit (GMRbeta). The human GMRalpha subunit also exists in a soluble isoform
(SOLalpha) which antagonizes GM-CSF activity in vitro. Previous studies by us
have shown that coexpression of SOLalpha and a mutated GMRbeta in BHK cells
results in retention of SOLalpha on the cell surface and the formation of an
intermediate affinity binding complex (Kd approximately 300 pM). This paper
investigates the mechanism of the retention of SOLalpha on the cell surface. The
data demonstrate that SOLalpha is anchored by a direct, ligand-independent
interaction with GMRbeta which also occurs when SOLalpha is coexpressed with wild
type GMRbeta. However, SOLalpha and wild-type GMRbeta form a complex which binds
GM-CSF with high affinity (Kd = 39 pM), indistinguishable from the binding
characteristics of the TMalpha/GMRbeta complex. The experiments further reveal
that the interaction between SOLalpha and GMRbeta is abrogated by removal of the
unique 16 amino acid carboxyl-terminal domain of SOLalpha. Specific mutation of
cysteine 323 in this carboxyl-domain to alanine also eliminates the cell-surface
retention of SOLalpha identifying this residue as being necessary for the
formation of the SOLalpha/GMRbeta complex.
PMID- 9760248
TI - Quantitative characterization of the binding of histamine by heparin.
AB - Tissue histamine is stored in mast cell granules, presumably as a histamine
heparin complex. Heparin is a polyelectrolyte, with a fraction of its anionic
charge neutralized by condensed counterions. The interaction of heparin with
histamine in aqueous solution was quantitatively characterized by 1H nuclear
magnetic resonance (NMR) spectroscopy. Binding constants were determined from
chemical shift-pH titration data for the C2H proton of the imidazolium ring for a
wide range of histamine, heparin, and Na+ concentrations. The results indicate a
binding stoichiometry of 1 histamine per heparin disaccharide repeat unit. The
binding is electrostatic, as indicated by the strong dependence of the binding
constant on Na+ concentration. From an analysis of the binding constants using
the counterion condensation theory of polyelectrolytes, it was determined that
the binding of H2A2+ results in displacement of 1.72 Na+ ions from the counterion
condensation volume of heparin and that H2A2+ makes 2 ionic interactions with
heparin. The displacement of Na+ from the counterion condensation volume of
heparin by H2A2+ was also studied by 23Na NMR. From 23Na spin-lattice relaxation
time data, it was determined directly that 1.78 Na+ ions are displaced per H2A2+
bound by heparin. The results are discussed in terms of the ion exchange process
which takes place when histamine is released by mast cells.
PMID- 9760249
TI - Membrane penetration of cytosolic phospholipase A2 is necessary for its
interfacial catalysis and arachidonate specificity.
AB - To determine the mechanism of calcium-dependent membrane binding of cytosolic
phospholipase A2 (cPLA2), we measured the interactions of cPLA2 with phospholipid
monolayers and polymerizable mixed liposomes containing various phospholipids. In
the presence of calcium, cPLA2 showed much higher penetrating power than
secretory human pancreatic PLA2 toward anionic and electrically neutral
phospholipid monolayers. cPLA2 also showed ca. 30-fold higher binding affinity
for nonpolymerized 2, 3-bis[12-(lipoyloxy)dodecanoyl]-sn-glycero-1
phosphoglycerol (D-BLPG) liposomes than for polymerized ones where the membrane
penetration of protein is significantly restricted. Consistent with this
difference in membrane binding affinity, cPLA2 showed 20-fold higher activity
toward fluorogenic substrates, 1-O-(1-pyrenedecyl)-2-arachidonoyl-sn-glycero-3
phosphocholine, inserted in nonpolymerized D-BLPG liposomes than the same
substrate in polymerized D-BLPG liposomes. Furthermore, cPLA2 showed much higher
sn-2 acyl group specificity (arachidonate specificity) and headgroup specificity
in nonpolymerized D-BLPG liposomes than in polymerized D-BLPG liposomes. Finally,
diacylglycerols, such as 1, 2-dioleoyl-sn-glycerol, selectively enhanced the
membrane penetration, hydrophobic membrane binding, and interfacial enzyme
activity of cPLA2. Taken together, these results indicate the following: (1)
calcium not only brings cPLA2 to the membrane surface but also induces its
membrane penetration. (2) This unique calcium-dependent membrane penetration of
cPLA2 is necessary for its interfacial binding and substrate specificity. (3)
Diacylglycerols might work as a cellular activator of cPLA2 by enhancing its
membrane penetration and hydrophobic membrane binding.
PMID- 9760250
TI - The influence of mutation at Glu44 and Glu56 of cytochrome b5 on the protein's
stabilization and interaction between cytochrome c and cytochrome b5.
AB - To characterize the roles played by Glu44 and Glu56 of cytochrome b5 in the
formation of the electrostatic complex between cytochrome c and cytochrome b5,
the Glu44, Glu56, or both sites were changed to alanine by site-directed
mutagenesis. The influence of these two residues on the protein stability was
probed by investigating the kinetic behaviors of protein denaturation in urea or
upon heating and the heme-transfer reactions between apo-myoglobin and the
variants of cytochrome b5. It has been found that when the Glu44 and/or Glu56 are
mutated to alanine, the protein stability increases slightly due to the fact that
the hydrophilic residue is changed to a hydrophobic one, resulting in the two
pairs of helices surrounding the heme taking a more compact conformation. The
difference in voltammetric behavior of cytochrome c, cytochrome b5, and its three
mutants, Cyt b5 E44A, E56A, and E44/56A, alone and in 1:1 protein complexes
demonstrates that both Glu44 and Glu56 of cytochrome b5 take part in the
electrostatic interaction with cytochrome c. The entropy changes, DeltaS
degreesrc and enthalpy changes, DeltaH degrees, derived from the temperature
dependence of the formal reduction potentials of each protein in different
protein systems suggest that, because of the mutual interaction with cytochrome
c, cytochrome b5 mutants, especially the E44A-containing mutants, in the protein
complexes suffer greater conformational changes upon reduction than that of the
wild type. The variation of these thermodynamic parameters indicates that the
strength of mutual interactions between cytochrome c and cytochrome b5 or its
mutants has the following order: Cyt c/Cyt b5 > Cyt c/Cyt b5 E56A > Cyt c/Cyt b5
E44A > Cyt c/Cyt b5 E44/56A.
PMID- 9760251
TI - N-tosyl-L-phenylalanine chloromethyl ketone, a serine protease inhibitor,
identifies glutamate 398 at the coenzyme-binding site of human aldehyde
dehydrogenase. Evidence for a second "naked anion" at the active site.
AB - Human aldehyde dehydrogenase isozymes were inactivated by N-tosyl-L-phenylalanine
chloromethyl ketone (TPCK), an inhibitor of chymotrypsin. The inactivation was a
first-order process that followed saturation kinetics. NAD and chloral when used
together protected against inactivation. In steady-state kinetics, TPCK produced
only slope effects versus varied NAD, both slope and intercept effects versus
varied glycolaldehyde were produced, indicating that TPCK reacted with the same
enzyme form with which NAD reacted. Ki values from steady-state kinetics and
saturation kinetics were comparable. Use of [3H]-labeled TPCK showed that
inactivation was associated with the incorporation of two molecules of TPCK per
molecule of enzyme. The label incorporation occurred into a single tryptic
peptide and also into a single chymotryptic peptide of the E1 isozyme.
Purification of labeled peptides, followed by sequencing, demonstrated that E398
of aldehyde dehydrogenase was labeled. Reaction of a haloketone, TPCK, with a
carboxyl group of E398 indicates that E398 occurs as a "naked anion" within the
molecule. This paper constitutes identification of the second (after E268) "naked
anion" at the active site of aldehyde dehydrogenase.
PMID- 9760252
TI - Kinetic studies on the removal of iron and aluminum from recombinant and site
directed mutant N-lobe half transferrins.
AB - Kinetic studies have been conducted in pH 7.4 Hepes buffer at 25 degreesC on the
removal of Fe(III) and Al(III) from the recombinant N-lobe half molecule of human
serum transferrin (Tf/2N) and from the R124A, K206A, and K296A mutants of this
protein. The rates of iron removal from Tf/2N by 3-hydroxypyridin-4-one
(deferiprone) and nitrilotriacetic acid (NTA) are essentially identical with
previous results on N-terminal monoferric transferrin (Tf-FeN). For both Tf/2N
and Tf-FeN, iron removal by deferiprone follows simple saturation kinetics, while
iron removal by NTA follows simple first-order kinetics. There is some
discrepancy between the two proteins with respect to iron removal by PPi, but
this may be due to differences in the chloride concentrations among different
studies. The addition of Fe(NTA)2 to R124A at ambient bicarbonate concentrations
forms the Fe-NTA-Tf ternary complex, but the usual Fe-CO3-Tf complex can be
formed by adding ferrous ion in the presence of a larger excess of bicarbonate.
This complex releases its iron very rapidly by a mechanism that is first-order
with respect to the ligand. This suggests that the first-order component of metal
release from transferrin involves the displacement of the synergistic carbonate
anion. Since iron removal from K206A and K296A at pH 7.4 is extremely slow,
studies have been conducted on the more labile Al3+ complexes of Tf/2N, K206A,
and K296A. The removal of Al3+ from Tf/2N by PPi follows the same complex kinetic
order with respect to the ligand concentration that is observed for iron removal,
while the removal of Al3+ from both K206A and K296A reverts to a simple
saturation process. The addition of perchlorate retards the removal of Al3+ from
both K206A and K296A, suggesting that these lysine residues are not associated
with the allosteric effects of inorganic anions on the rates of metal removal.
PMID- 9760253
TI - Oxidative modification of aldose reductase induced by copper ion. Factors and
conditions affecting the process.
AB - Bovine lens aldose reductase (ALR2) is inactivated by copper ion [Cu(II)] through
an oxygen-independent oxidative modification process. A stoichiometry of 2 equiv
of Cu(II)/enzyme mol is required to induce inactivation. While metal chelators
such as EDTA or o-phenantroline prevent but do not reverse the ALR2 inactivation,
DTT allows the enzyme activity to be rescued by inducing the recovery of the
native enzyme form. The inactive enzyme form is characterized by the presence of
2 equiv of bound copper, at least one of which present as Cu(I), and by the
presence of two lesser equivalents, with respect to the native enzyme, of reduced
thiol residues. Data are presented which indicate that the Cu-induced protein
modification responsible for the inactivation of ALR2 is the generation on the
enzyme of an intramolecular disulfide bond. GSH significantly interferes with the
Cu-dependent inactivation of ALR2 and induces, through its oxidation to GSSG, the
generation of an enzyme form linked to a glutathionyl residue by a disulfide
bond.
PMID- 9760254
TI - Novel function of the regulatory subunit of protein kinase A: regulation of
cytochrome c oxidase activity and cytochrome c release.
AB - There have been speculations that the regulatory (R) subunit of the cAMP
dependent protein kinase (PKA) may have other functions. A recent study has shown
that the catalytic (C) subunit of PKA may be regulated in a cAMP- and R subunit
independent manner. However, evidence linking a function to the R subunit apart
from inhibiting the C subunit has been elusive. In this report, interaction
cloning experiments showed that the RIalpha subunit association with the
cytochrome c oxidase subunit Vb (CoxVb) is cAMP-sensitive. Interaction was
detected with a GST-RIalpha fusion protein as well as by coimmunoprecipitation.
Transient treatment with cAMP-elevating agents inhibited cytochrome c oxidase in
Chinese hamster ovary (CHO) cells with a concomitant decrease in cytochrome c
levels in the mitochondria and an increase in its release into the cytosol.
Furthermore, mutant cells harboring a defective RIalpha show increased cytochrome
c oxidase activity and also constitutively lower levels of cytochrome c in
comparison to either the wild-type cells or the C subunit mutant. These results
suggest a novel mechanism of cAMP signaling through the interaction of RIalpha
with CoxVb thereby regulating cytochrome c oxidase activity as well as the
cytochrome c levels.
PMID- 9760255
TI - Analysis of the TPA regulatory element in the genomic poly(ADP-ribose) synthetase
gene in human leukemia U937 cells.
AB - The human leukemia U937 cells differentiate into monocyte/macrophage-like cells
when treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). We observed that
during this process, both protein and mRNA levels for PARS markedly decreased in
U937 cells. Through deletion analysis of the PARS regulatory gene, we found that
the sequence within the first intron region was responsible for the TPA-dependent
repression. Electrophoretic mobility shift assays (EMSAs) and Southwestern blot
analysis indicate that this element bound specifically to a nuclear protein. TPA
treatment abolished the binding of the protein in U937 cells but not in HeLa
cells. DNase I footprinting data show that the cis regulatory element is located
between residues 328 and 383. We further examined the function of this cis
element (BS207) in a basal promoter regulatory reporter construct and found that
this cis element (BS207) functions as an enhancer via the binding of an unknown
trans-acting factor. TPA treatment diminished the binding activity of the factor
in U937 cells, resulting in a decrease in the enhanced activity to the basal
level. These results suggest that abolishment of the binding of a special nuclear
protein to the first intron of the PARS gene is related to the TPA-responsive
downregulation of PARS in U937 cells.
PMID- 9760256
TI - Implication of the tRNA initiation step for human immunodeficiency virus type 1
reverse transcriptase in the mechanism of 3'-azido-3'-deoxythymidine (AZT)
resistance.
AB - There is a lack of correlation between biochemical studies and the observed
clinical resistance of AIDS patients on long-term AZT therapy. Mutant HIV-1
reverse transcriptase in the viral isolates from these patients shows a 100-fold
decrease in sensitivity to AZT whereas little or no difference is observed in
kinetic parameters in vitro using steady-state kinetic analysis. A pre-steady
state kinetic analysis was used to examine the binding and incorporation of 2'
deoxythymidine 5'-triphosphate (dTTP) and 3'-azido-3'-deoxythymidine 5'
triphosphate (AZTTP) by wild-type HIV-1 reverse transcriptase and a clinically
important AZT-resistant mutant form of the enzyme (D67N, K70R, T215Y, K219Q)
utilizing a physiologically relevant RNA 18-mer/RNA 36-mer primer-template
substrate. It was determined that with this RNA/RNA substrate there is a 2.6-fold
increase in the selection for incorporation of the natural nucleotide dTTP over
the unnatural nucleoside analogue AZTTP by AZT-resistant reverse transcriptase as
compared to its wild-type form. This observation indicates that the tRNALys
initiation step plays an important role in the development of drug resistance.
Furthermore, this result implies that the structural basis of AZT resistance in
HIV-1 reverse transcriptase involves the conformation of the RNA-DNA junction
(formed upon attachment of a deoxynucleotide to the RNA primer). Taken together,
these observations suggest a new pharmacological basis for the development of
more effective and novel AIDS drugs.
PMID- 9760257
TI - Structure and activity of the hairpin ribozyme in its natural junction
conformation: effect of metal ions.
AB - The natural form of the hairpin ribozyme consists of a four-way RNA junction of
which the single-stranded loop-carrying helices are adjacent arms. The junction
can be regarded as providing a framework for constructing the active ribozyme,
and the rate of cleavage can be modulated by changing the conformation of the
junction. We find that the junction-based form of the hairpin ribozyme is active
in magnesium, calcium, or strontium ions, but not in manganese, cadmium, or
sodium ions. Using fluorescence resonance energy transfer experiments, we have
investigated the global structure of the ribozyme. The basic folding of the
construct is based on pairwise helical stacking, so that the two loop-carrying
arms are located on opposite stacked helical pairs. In the presence of magnesium,
calcium, or strontium ions, the junction of the ribozyme undergoes a rotation
into a distorted antiparallel geometry, creating close physical contact between
the two loops. Manganese ions induce the same global folding, but no catalytic
activity; this change in global conformation is therefore necessary but not
sufficient for catalytic activity. Fitting the dependence of the conformation on
ionic concentration to a two-state model suggests that cooperative binding of two
ions is required to bring about the folding. However, further ion binding is
required for cleavage activity. Cobalt hexammine ions also bring about global
folding, while spermidine generates a more symmetrical form of the antiparallel
structure. Cadmium ions generate a different folded form, interpreted in terms of
close loop-loop association while the junction is unfolded. Sodium ions were
unable to induce any folding of the ribozyme, which remained slightly parallel.
These results are consistent with a folding process induced by the binding of two
group IIA metal ions, distributed between the junction and the loop interface.
PMID- 9760258
TI - Inhibitors of protein-RNA complexation that target the RNA: specific recognition
of human immunodeficiency virus type 1 TAR RNA by small organic molecules.
AB - TAR RNA represents an attractive target for the intervention of human
immunodeficiency virus type 1 (HIV-1) replication by small molecules. We now
describe three small molecule inhibitors of the HIV-1 Tat-TAR interaction that
target the RNA, not the protein. The chemical structures and RNA binding
characteristics of these inhibitors are unique for each molecule. Results from
various biochemical and spectroscopic methods reveal that each of the three Tat
TAR inhibitors recognizes a different structural feature at the bulge, lower
stem, or loop region of TAR. Furthermore, one of these Tat-TAR inhibitors has
been demonstrated, in cellular environments, to inhibit (a) a TAR-dependent, Tat
activated transcription and (b) the replication of HIV-1 in a latently infectious
model.
PMID- 9760259
TI - Actinomycin D inhibition of DNA strand transfer reactions catalyzed by HIV-1
reverse transcriptase and nucleocapsid protein.
AB - Actinomycin D was found to be a potent inhibitor of HIV-1 reverse transcriptase
catalyzed DNA strand transfer reactions. Using an oligonucleotide model system,
actinomycin D inhibition of DNA strand transfer was examined to elucidate the
mechanism of inhibition and further define the mechanism of DNA strand transfer.
Our results show that actinomycin D inhibits HIV-1 reverse transcriptase
catalyzed DNA strand transfer without inhibiting RNA-dependent or DNA-dependent
DNA polymerase activity. Actinomycin D was found to strongly inhibit annealing of
a primary DNA product to the DNA acceptor template, preventing the formation of a
key reaction intermediate. The HIV-1 nucleocapsid protein has been shown to
participate in catalytic events during reverse transcription including DNA strand
transfer. Recombinant nucleocapsid protein was used in conjunction with
actinomycin D in this model system to investigate how NC may participate in the
mechanism of inhibition by actinomycin D and in DNA strand transfer. The
inclusion of nucleocapsid protein was found to partially relieve both DNA
annealing and strand transfer inhibition caused by actinomycin D. This study
suggests a potential new mechanism for inhibiting retroviral replication by
preventing the formation of replication intermediates.
PMID- 9760260
TI - Ceruloplasmin copper induces oxidant damage by a redox process utilizing cell
derived superoxide as reductant.
AB - Oxidative damage by transition metals bound to proteins may be an important
pathogenic mechanism. Ceruloplasmin (Cp) is a Cu-containing plasma protein
thought to be involved in oxidative modification of lipoproteins. We have
previously shown that Cp increased cell-mediated low-density lipoprotein (LDL)
oxidation by a process requiring cell-derived superoxide, but the underlying
chemical mechanism(s) is (are) unknown. We now show that superoxide reduction of
Cp Cu is a critical reaction in cellular LDL oxidation. By bathocuproine
disulfonate (BCS) binding and by superoxide utilization, we showed that exogenous
superoxide reduces a single Cp Cu atom, the same Cu required for LDL oxidation.
The Cu atom remained bound to Cp during the redox cycle. Three avenues of
evidence showed that vascular cells reduce Cp Cu by a superoxide-dependent
process. The 2-fold higher rate of Cp Cu reduction by smooth muscle cells (SMC)
compared to endothelial cells (EC) was consistent with their relative rates of
superoxide release. Furthermore, Cp Cu reduction by cells was blocked by Cu,Zn
superoxide dismutase (SOD1). Finally, the level of superoxide produced by EC and
SMC was sufficient to cause the amount of Cu reduction observed. An important
role of Cp Cu reduction in LDL oxidation was suggested by results showing that
SOD1 inhibited Cp Cu reduction and LDL oxidation by SMC with equal potency, while
tumor necrosis factor-alpha stimulated both processes. In summary, these results
show that superoxide is a critical cellular reductant of divalent transition
metals involved in oxidation, and that protein-bound Cu is a substrate for this
reaction. The role of these mechanisms in oxidative processes in vivo has yet to
be defined.
PMID- 9760262
TI - Proton transfer reactions linked to rhodopsin activation.
AB - Purified bovine rhodopsin solubilized in dodecyl maltoside was photolyzed at 20
degreesC with 477 nm light, and difference spectra were collected at time delays
ranging from 10 micros to 10 ms after photolysis. Bromocresol purple was added to
the samples to detect pH changes in the aqueous environment due to changes in the
protonation state of rhodopsin. The data were analyzed using singular value
decomposition and global exponential fitting, which revealed three exponential
processes indicating the presence of at least four intermediates. Spectral
changes of the indicator dye were separated from those of rhodopsin, and proton
release and uptake rates were analyzed within the framework of rhodopsin
photoreaction kinetics. Proton release occurred during Lumi decay to Meta-I380
followed by uptake upon Meta-I380 decay and by a more significant proton uptake
with the time course of Meta-I480 decay. On the basis of the estimated number of
protons released and taken up in each step of the rhodopsin photoreaction, we
concluded that two forms of Meta-II are present. The two forms of Meta-II, Meta
IIa' and Meta-IIb, differ in protonation state from one another as do both from
the earlier, 380 nm absorbing form, Meta-I380.
PMID- 9760261
TI - The carboxyl-terminal tripeptide of the manganese-stabilizing protein is required
for quantitative assembly into photosystem II and for high rates of oxygen
evolution activity.
AB - The extrinsic manganese stabilizing protein of photosystem II is required for Mn
retention by the O2-evolving complex, accelerates the rate of O2 evolution, and
protects photosytem II against photoinhibition. We report results from studies of
the in vitro reconstitution of spinach photosytem II with recombinant manganese
stabilizing protein with C-terminal deletions of two, three, and four amino
acids. The deletions were the result of amber mutations introduced by site
directed mutagenesis. Removal of the C-terminal dipeptide (Glu-Gln) did not
diminish the ability of the manganese stabilizing protein either to rebind to or
to restore high rates of O2 evolution to photosystem II preparations depleted of
the native protein. Deletion of the C-terminal tripeptide (Leu-Glu-Gln) resulted
in weakened but specific binding of manganese stabilizing protein to photosystem
II and minimal recovery of O2 evolution activity. Removal of the C-terminal
tetrapeptide (Gln-Leu-Glu-Gln) eliminated the ability of the subunit to interact
stably with all of its available binding sites on photosystem II, as evidenced by
the fact that this mutant was totally inactive in restoring O2 evolution
activity. Evidence is presented to indicate that these mutational effects on the
binding and function of the manganese stabilizing protein may be due to major
changes in tertiary structure. The truncation mutations lacking either the C
terminal tri- or tetrapeptide exhibit apparent size increases of 25 and 40%,
respectively, when compared either to a mutant lacking the C-terminal dipeptide
or to the wild-type protein.
PMID- 9760264
TI - Kinetics of dimerization and interactions of p13suc1 with cyclin-dependent
kinases.
AB - The impact of p13suc1 on the conformation and regulation of cyclin-dependent
kinases (cdks) and cyclins was investigated by spectroscopic and rapid kinetic
approaches. In the absence of phosphorylation on cdks, p13suc1 formed stable
complexes, mainly stabilized by hydrophobic interactions, specifically with cdk2
and cdc2. The presence of cyclin A, associated with cdk2 or cdc2, increased the
stability of the interaction between cdk2 and p13suc1 by a factor of 2. However,
cyclin A did not modify the association rate of p13suc1 to cdk2, but the
dissociation rate, which was decreased 3-fold. Moreover, binding of p13suc1 to
cdk2 resulted in a 2-fold decrease in the release of nucleotide from cdk2,
indicating that p13suc1 induces a marked change in the structure of the
nucleotide binding site of cdks. On the basis of the structure of cdk2/CksHs1
complex and on our kinetic results, we propose that the binding of Cks proteins
to C-lobe of cdk2 is stabilized by the presence of cyclin A and that it may
modify the orientation of the loop carrying residues 14 and 15 and their
consequent access for dephosphorylation by cdc25 phosphatases. Finally, we have
shown that dimerization of p13suc1 in the presence of zinc abolishes its
interaction with cdks, which suggests that the binding of p13suc1 to cdk2 or
cdk2/cyclin A may be regulated by dimerization of p13suc1 in vivo.
PMID- 9760263
TI - Involvement of histidine 190 on the D1 protein in electron/proton transfer
reactions on the donor side of photosystem II.
AB - Flash-induced chlorophyll fluorescence kinetics from photosystem II in thylakoids
from the dark-grown wild type and two site-directed mutants of the D1 protein
His190 residue (D1-H190) in Chlamydomonas reinhardtii have been characterized.
Induction of the chlorophyll fluorescence on the first flash, reflecting electron
transport from YZ to P680(+), exhibited a strong pH dependence with a pK of 7.6
in the dark-grown wild type which lacks the Mn cluster. The chlorophyll
fluorescence decay, measured in the presence of DCMU, which reflects
recombination between QA- and YZox, was also pH-dependent with a similar pK of
7.5. These results indicate participation by the same base, which is suggested to
be D1-H190, in oxidation and reduction of YZ in forward electron transfer and
recombination pathways, respectively. This hypothesis was tested in the D1-H190
mutants. Induction of chlorophyll fluorescence in these H190 mutants has been
observed to be inefficient due to slow electron transfer from YZ to P680(+)
[Roffey, R. A., et al. (1994) Biochim. Biophys. Acta 1185, 257-270]. We show that
this reaction is pH-dependent, with a pK of 8. 1, and at pH >/=9, the
fluorescence induction is efficient in the H190 mutants, suggesting direct
titration of YZ. The efficient oxidation of YZ ( approximately 70% at pH 9.0) at
high pH was confirmed by kinetic EPR measurements. In contrast to the wild type,
the H190 mutants show little or no observable fluorescence decay. Our data
suggest that H190 is an essential component in the electron transfer reactions in
photosystem II and acts as a proton acceptor upon YZ oxidation. In the H190
mutants, this reaction is inefficient and YZ oxidation only occurs at elevated
pHs when YZ itself probably is deprotonated. We also propose that H190 is able to
return a proton to YZox during electron recombination from QA- in a reaction
which does not take place in the D1-H190 mutants.
PMID- 9760265
TI - A Raman spectroscopic characterization of bonding in the complex of horse liver
alcohol dehydrogenase with NADH and N-cyclohexylformamide.
AB - The binding of N-cyclohexylformamide (CXF) to the complex of horse liver alcohol
dehydrogenase with NADH mimics that of the Michaelis complex for aldehyde
reduction catalyzed by the enzyme. The Raman spectra of bound CXF and its 13C-
and 15N-substituted derivatives have been obtained using Raman difference
techniques, and the results are compared with CXF spectra in aqueous solution and
in methylene chloride. The results indicate that the amide N-H bond is trans to
the C=O bond of CXF both in solution and in the enzyme ternary complex. The C=O
stretch and N-H bending modes of the amide of CXF shift -16 and -9 cm-1,
respectively, in the enzyme ternary complex relative to that in aqueous solution
and -48 and 36 cm-1, respectively, relative to that in methylene chloride. Ab
initio normal mode calculations on various model systems of CXF show that the
observed frequency changes of the C=O stretch mode have contributions from the
frequency changes induced by the environmental changes near both the local C=O
bond and the remote N-H bond. The same is true for the observed N-H bending
frequency change. Our calculations also show that the environmentally induced
frequency changes are additive so that it is possible to determine the C=O
stretch (or N-H bending) frequency change that is due to the local interaction
change near the C=O (or N-H) bond from the observed frequency changes. On the
basis of these results and the empirical relationship between the C=O stretch
frequency shift and the interaction enthalpy change on the C=O bond developed
here, it is found that the C=O group of CXF in the enzyme/NADH/CXF complex binds
with a favorable interaction enthalpy of approximately 5.5 kcal/mol relative to
water. Similar analysis suggests that the N-H moiety of CXF is destabilized in
the ternary complex by about 1.5 kcal/mol relative to water but is stabilized by
about 1.5 kcal/mol relative to a hydrophobic environment. The analysis describes
quantitatively the binding of the C=O of CXF with the catalytic zinc and the
hydroxyl group of Ser-48 and the interaction of the N-H with the benzene ring of
Phe-93 of the enzyme.
PMID- 9760266
TI - Environment- and sequence-dependent modulation of the double-stranded to single
stranded conformational transition of gramicidin A in membranes.
AB - The role of the membrane lipid composition and the individual Trp residues in the
conformational rearrangement of gramicidin A along the folding pathway to its
channel conformation has been examined in phospholipid bilayers by means of
previously described size-exclusion high-performance liquid chromatography HPLC
based strategy (Bano et al. (1991) Biochemistry 30, 886). It has been
demonstrated that the chemical composition of the membrane influences the
transition rate of the peptide rearrangement from double-stranded dimers to beta
helical monomers. The chemical modification of Trp residues, or its substitution
by the more hydrophobic residues phenylalanine or naphthylalanine, stabilized the
double-stranded dimer conformation in model membranes. This effect was more
notable as the number of Trp-substituted residues increased (tetra > tri > di >
mono), and it was also influenced by the specific position of the substituted
amino acid residue in the sequence, in the order Trp-9 approximately Trp-13 > Trp
11 > Trp-15. Moreover, it was verified that nearly a full contingent of indoles
(Trp-13, -11, and -9) is necessary to induce a quantitative conversion from
double-stranded dimers to single-stranded monomers, although Trp-9 and Trp-13
seemed to be key residues for the stabilization of the beta-helical monomeric
conformation of gramicidin A. The conformation adopted for monomeric Trp --> Phe
substitution analogues in lipid vesicles resulted in CD spectra similar to the
typical single-stranded beta6.3-helical conformation of gramicidin A. However,
the Trp --> Phe substitution analogues showed decreased antibiotic activity as
the number of Trp decreased.
PMID- 9760268
TI - The helix-coil transition of DNA duplexes and hairpins observed by multiple
fluorescence parameters.
AB - The thermal denaturation of 8-20-bp DNA duplexes labeled with fluorescein and
tetramethylrhodamine at opposing 5'-ends was investigated by monitoring the
fluorescence intensity of the dyes, the fluorescence anisotropy of
tetramethylrhodamine, the fluorescence resonance energy transfer between
fluorescein and rhodamine, and, for the 20-bp duplex, the UV absorption. Melting
experiments with the single strands of the duplexes revealed that the single
strands can form hairpins stabilized by only a few base pairs. The thermal
denaturation curves of the duplexes were fitted well to an extended all-or-none
model assuming that only the fully base-paired duplex, the maximally base-paired
hairpin, and the random coil conformations are present simultaneously. The extent
of-melting versus temperature curves derived from the different spectroscopic
parameters are nearly identical, provided that the analysis of the baselines is
carried out correctly; the DeltaH and DeltaS of the dissociation compare well
with predictions based on nearest neighbor interaction values available in the
literature. Our results imply that for all the oligonucleotides other than the 34
bp oligomer, no partially melted intermediates other than hairpins are present in
the reaction mixture in amounts that can be detected by our methods. The melting
of the hairpins was also studied directly using single-stranded oligonucleotides.
The melting of a 34-bp duplex can be accounted for by a statistical zipper model.
PMID- 9760267
TI - Transient kinetic studies on the interaction of Ras and the Ras-binding domain of
c-Raf-1 reveal rapid equilibration of the complex.
AB - Transient kinetic methods have been used to analyze the interaction between the
Ras-binding domain (RBD) of c-Raf-1 and a complex of H-Ras and a GTP analogue.
The results obtained show that the binding is a two-step process, with an initial
rapid equilibrium step being followed by an isomerization reaction occurring at
several hundred per second. The reversal of this step determines the rate
constant for dissociation, which is on the order of 10 s-1. The lifetime of the
complex is therefore on the order of 50-100 ms, which is much shorter than the
lifetime of GTP at the active site of H-Ras as determined by the intrinsic GTPase
reaction. This suggests that multiple interactions of a single activated Ras
molecule and Raf can occur, the number being limited by the competing interaction
with GAP. The GDP complex of H-Ras binds more than 2 orders of magnitude more
weakly than the GTP-analogue complex, mainly due to a significant weakening of
the initial binding equilibrium reaction in the GDP state, thereby avoiding even
short-lived recruitment of Raf to the plasma membrane by the inactive Ras form.
PMID- 9760269
TI - Human cruciform binding protein belongs to the 14-3-3 family.
AB - Cruciform DNA has been implicated in the initiation of DNA replication. Recently,
we identified and purified from human (HeLa) cells a protein, CBP, with binding
specificity for cruciform DNA. We have reported previously that the CBP activity
sediments at approximately 66 kDa in a glycerol gradient. Here, photochemical
cross-linking studies and Southwestern analyses confirm that a 70 kDa polypeptide
interacts specifically with cruciform DNA. Microsequence analysis of tryptic
peptides of the 70 kDa CBP reveals that it is 100% homologous to the 14-3-3
family of proteins and shows that CBP contains the epsilon, beta, gamma, and zeta
isoforms of the 14-3-3 family. In addition to polypeptides with the
characteristic molecular mass of 14-3-3 proteins (30 and 33 kDa), CBP also
contains a polypeptide of 35 kDa which is recognized by an antibody specific for
the epsilon isoform of 14-3-3. Cruciform-specific binding activity is also
detected in 14-3-3 proteins purified from sheep brain. Immunofluorescene studies
confirm the presence of the epsilon, beta, and zeta isoforms of 14-3-3 proteins
in the nuclei of HeLa cells. The 14-3-3 family of proteins has been implicated in
cell cycle control, and members of this family have been shown to interact with
various signaling proteins. Cruciform binding is a new activity associated with
the 14-3-3 family.
PMID- 9760270
TI - Binding and reactivity of Candida albicans estrogen binding protein with steroid
and other substrates.
AB - In this report recombinant estrogen binding protein (EBP1), isolated originally
from Candida albicans as a result of its high affinity for 17beta-estradiol, has
been purified extensively using a modified affinity purification scheme
originally developed for a homolog of EBP1, old yellow enzyme (OYE). It is shown
that like OYE, the protein binds a variety of compounds with a phenolic
structure, including 17beta-estradiol, and compounds with an alpha, beta
unsaturated keto or aldehyde structure. In addition, EBP1 exhibits an NADPH
oxidoreductase activity, transferring electrons from NADPH to all alpha,beta
unsaturated ketones and aldehydes tested via the tightly bound FMN cofactor.
Analysis of the steady-state kinetics of these reactions indicate a tetra uni
ping-pong mechanism. Inhibition of the steady-state reaction by 17beta-estradiol
gives a Ki = 10 +/- 2 nM, and indicates exclusive binding of this steroid to the
enzyme in its oxidized state. In contrast, 19-nortestosterone binds to both
oxidized and reduced forms of the enzyme with dissociation constants of 600 +/-
100 and 650 +/- 90 nM, respectively. EBP1 also catalyzes a disproportionation
reaction with certain compounds, in which two molecules of a cylic alpha,beta
unsaturated ketone, including the steroid 19-nortestosterone, are individually
aromatized and reduced to the corresponding saturated ketone. Despite the
extensive similarity in sequence and enzymic activity, notable differences
between EBP1 and the OYE family of proteins exist with regard to the binding
behavior and reactivity with the two steroids tested here, estradiol and 19
nortestosterone.
PMID- 9760271
TI - Role of drug disposition in drug hypersensitivity: a chemical, molecular, and
clinical perspective.
PMID- 9760272
TI - Formation of a fluorescent adduct in the reaction of 2'-deoxyadenosine with a
malonaldehyde-acetaldehyde condensation product.
AB - Malonaldehyde (malondialdehyde, MDA) was reacted with 2'-deoxyadenosine in
buffered aqueous solution. HPLC analyses of the reaction mixtures showed that,
besides the two previously characterized N6-propenal (M1dA) and N6-oxazocinyl
(M3dA) adenine adducts, a third compound eluting at longer retention time was
formed. The compound generated a strong peak in the chromatogram recorded by a
fluorescence detector. The new compound was isolated by preparative C18
chromatography, and its structure was characterized by UV absorbance,
fluorescence emission, 1H and 13C NMR spectroscopy, and mass spectrometry. The
product was identified as 9-(2'-deoxyribosyl)-6-(3,5-diformyl-4-methyl-1, 4
dihydro-1-pyridyl)purine (M2AA-dA). The yield of the product was 0.8% following 7
days of reaction at 37 degreesC and pH 4.6. Lower yields were obtained at higher
pH conditions. By the addition of acetaldehyde, the yield increased about 10-fold
at all studied pH conditions. The adduct was most likely formed by an initial
condensation of two molecules of malonaldehyde with one molecule of acetaldehyde
followed by reaction of the condensation product with the exocyclic amino group
of 2'-deoxyadenosine. The identification of this adduct shows that acetaldehyde
may react with DNA bases also through an initially formed malonaldehyde
acetaldehyde condensation product.
PMID- 9760273
TI - Generation of antibodies to Di- and trichloroacetylated proteins and
immunochemical detection of protein adducts in rats treated with perchloroethene.
AB - Antibodies directed against chemical specific protein modifications are valuable
tools to detect and comparatively quantify protein modifications. Both Nepsilon
(dichloroacetyl)-L-lysine and Nepsilon-(trichloroacety)l-L-lysine have been
detected as modified amino acids in liver and kidneys of rats treated with
perchloroethene (PER) after proteolysis. These protein modifications are formed
by the interaction of reactive metabolites formed from PER with proteins. In this
study we developed monospecific antibodies to dichloroacetylated and to
trichloroacetylated amino acids to detect modified proteins in the target organs
of PER toxicity. These antibodies were prepared by immunization of rabbits with
modified keyhole limpet hemocyanin (KLH) coupled with either the dichloroacetyl
or trichloroacetyl moiety. Enzyme-linked immunosorbent assays (ELISA) indicated
that the polyclonal rabbit sera recognized dichloroacetylated or
trichloroacetylated rabbit serum albumin (RSA), but not unmodified protein.
Therefore, we further purified rabbit antisera on either Nepsilon
(dichloroacetyl)-L-lysine or Nepsilon-(trichloroacetyl)-L-lysine immobilized to
immunoaffinity columns to obtain monospecific antibodies. The potential of these
antibodies in the detection of di- and trichloroacetylated proteins and their
selectivity for the desired dichloroacetyl or trichloroacetyl group was
demonstrated in competitive enzme-linked immunosorbent assays with several
structurally related compounds. Anti-dichloroacetyl (anti-DCA) antibody binding
to dichloroacetylated RSA was inhibited by Nepsilon-(dichloroacetyl)-L-lysine
with an IC50 value of 150 microM whereas inhibition by Nepsilon
(monochloroacetyl)-L-lysine and Nepsilon-(trichloroacetyl)-L-lysine showed an
IC50 value of 100 mM. The binding of the anti-trichloroacetyl (anti-TCA) antibody
to trichloroacetylated RSA was inhibited by Nepsilon-(dichloroacetyl)-L-lysine
with an IC50 value of 80 mM. The inhibition by Nepsilon-(trichloroacetyl)-L
lysine was again 3 orders of magnitude stronger resulting in an IC50 value of 90
microM. Nepsilon-(acetyl)-L-lysine and unmodified RSA did not effect antibody
binding to the chemically modified antigen. The antibodies were also successfully
applied to detect modified proteins in subcellular fractions of liver and kidney
from PER treated rats demonstrated in immunoblot. Protein adduct formation from
different PER metabolism pathways was confirmed by the observation that the
majority of dichloroacetylated proteins were located in kidney mitochondria and
trichloroacetylated proteins were located in liver microsomes.
PMID- 9760274
TI - A novel vicinal lesion obtained from the oxidative photosensitization of TpdG:
characterization and mechanistic aspects.
AB - A new type of vicinal base lesion was isolated from the photosensitization of
TpdG in aerated aqueous solution. One- and two-dimensional NMR measurements were
used together with mass spectrometry to accurately characterize the new adduct.
Chemical detection of guanidine provided additional structural information on the
base moiety at the 3'-OH terminal end. Altogether the experiments results were
indicative of the occurrence of a covalent bonding between the pyrimidine ring on
the 5'-OH terminal end and the imidazole ring on the 3'-OH terminal end through a
methylene bridge. Photosensitization studies of TpdG, thymidine, and 2'
deoxyguanosine in the presence of either benzophenone, menadione, or riboflavin
associated with isotopic labeling experiments using enriched oxygen and water
provided relevant information on the mechanism of formation of the adduct. The
results of these experiments clearly demonstrated that the initial event leading
to the formation of the lesion is the abstraction of a hydrogen atom from the
methyl group of the thymine base moiety of TpdG. This is followed by the addition
of the methyl-centered radical to the C-4 atom of the guanine ring which gives
rise to the vicinal lesion after reaction with molecular oxygen and subsequent
rearrangement.
PMID- 9760275
TI - Interactions of Nickel(II) with histones: interactions of Nickel(II) with CH3CO
Thr-Glu-Ser-His-His-Lys-NH2, a peptide modeling the potential metal binding site
in the "C-Tail" region of histone H2A.
AB - A combined pH-metric and spectroscopic (UV/vis, CD, NMR) study of the Ni(II)
binding to CH3CO-Thr-Glu-Ser-His-His-Lys-NH2 (AcTESHHKam), a blocked hexapeptide
modeling a part of the C-terminal sequence of the major variant of histone H2A
(residues 120-125), revealed the formation of a pseudo-octahedral NiHL complex in
weakly acidic and neutral solutions. Ni(II) is bound to the peptide through
imidazole nitrogens on both of its histidine residues and the carboxylate of the
side chain of glutamic acid. At higher pH, a series of square-planar complexes
are formed. This process is accompanied by hydrolytic degradation of the peptide.
At pH 7.4, the peptide hydrolyzes in a Ni(II)-assisted fashion, yielding the
square-planar Ni(II) complex of SHHKam as the sole product detected by CD, MALDI
TOF MS, and HPLC. Quantitative analysis of complex stabilities indicates that the
-TESHHK- motif is a very likely binding site for carcinogenic Ni(II) ions in the
cell nucleus. The Ni(II)-assisted hydrolysis of the C-terminal chain of histone
H2A may provide a novel mechanism of genotoxicity combining the damage to the
nucleosome with the generation of further toxic Ni(II) species.
PMID- 9760276
TI - Activation of human polymorphonuclear leukocytes by products derived from the
peroxidation of human red blood cell membranes.
AB - Oxidation of red blood cell (RBC) ghost preparations initiated by tert-butyl
hydroperoxide (tBuOOH) was employed to explore the formation of lipid products
derived from endogenous phospholipids that specifically expressed biological
activity toward the human polymorphonuclear leukocyte (PMN). Common measure of
lipid peroxidation, thiobarbituric acid-reactive substances (TBARS) and the
increased absorbance at 235 nm consistent with the formation of conjugated
dienes, was observed following a 90-min incubation of RBC ghosts with tBuOOH.
Saponification of phospholipids and separation of the resultant fatty acids by RP
HPLC permitted direct mass spectrometric analysis of oxidized fatty acids.
Individual HPLC fractions were assayed for their ability to increase
intracellular free calcium ion concentrations in human PMN to guide structural
investigations. Two fractions were found to contain biologically active
components, and tandem mass spectrometric analysis of the abundant ions observed
in these fractions resulted in the characterization of several oxidized
polyunsaturated fatty acids derived from arachidonic and linoleic acids. The
major components in these fractions included 5-hydroxyeicosatetraenoic acid (5
HETE) and 5-hydroperoxyeicosatetraenoic acid (5-HpETE). The dose-dependent
increases in intracellular calcium in the neutrophil using synthetic 5(rac)-HETE,
5(rac)-HpETE, and 5-oxo-ETE were found to have EC50's of 250, 6, and 3 nM,
respectively. The quantity of 5-oxygenated arachidonate components present in
oxidized RBC was consistent with the observed biological response elicited by
fractions A and B. This study suggests that 5-HETE and 5-HpETE are abundant
products of lipid peroxidation of cellular membranes and that these racemic
products possess significant biological activity. Such compounds could play
important roles as mediators of the cellular response to toxicologic stimuli that
generate free radical species.
PMID- 9760277
TI - An improved 32P-postlabeling/high-performance liquid chromatography method for
the analysis of the malondialdehye-derived 1, N2-propanodeoxyguanosine DNA adduct
in animal and human tissues.
AB - Malondialdehyde (MDA) is a major lipid peroxidation product that is mutagenic and
tumorigenic. The MDA-modified DNA adduct, 3-(2-deoxy-beta-D-erythro
pentofuranosyl)pyrimido[1, 2-alpha]purin-10(3H)-one (M1G), has been detected in
human tissues and may be a marker of human cancer risk. In this paper, we
describe an improved 32P-postlabeling/HPLC method for sensitive detection and
quantitation of this MDA-modified 2'-deoxyribonucleotide adduct. Specific
improvements include (i) unequivocal structural identification of the
postlabeling products, both the 3', 5'-bisphosphate of M1G (MDA-3',5'-dGDP) and
the 5'-monophosphate of M1G (MDA-5'-dGMP); (ii) efficient separation of the 32P
postlabeling products by HPLC; and (iii) the incorporation of a synthetically
prepared MDA-modified DNA (or the 3'-monophosphate of M1G) with a known
modification level as an internal standard. This improved quantitative
methodology provides high intra- and inter-assay reproducibility and has been
applied to the analysis of this adduct in rodent and human samples.
PMID- 9760278
TI - Formation of 1,N6-etheno-2'-deoxyadenosine adducts by trans,trans-2, 4
Decadienal.
AB - trans,trans-2,4-Decadienal (DDE) is an important breakdown product of lipid
peroxidation. This aldehyde is cytotoxic to mammalian cells and is known to be
implicated in DNA damage. Therefore, attempts were made in this work to assess
the reactivity of DDE with 2'-deoxyadenosine (dAdo). It was shown that DDE is
able to bind to 2'-deoxyadenosine, yielding highly fluorescent products. Besides
1, N6-etheno-2'-deoxyadenosine (epsilondAdo), two other related adducts, 1-[3-(2
deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1-i]purin-7-yl]-1,2,3
octanetriol and 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2, 1
i]purin-7-yl]-1,2-heptanediol, were isolated by reverse phase high-performance
liquid chromatography and characterized on the basis of their UV, fluorescence,
nuclear magnetic resonance, and mass spectrometry features. The reaction
mechanism for the formation of the DDE-2'-deoxyadenosine adducts involves 2,4
decadienal epoxidation and subsequent addition to the N2 amino group of 2'
deoxyadenosine, followed by cyclization at the N-1 site. Adducts differ by the
length of carbon side chain and the number of hydroxyl groups. The present data
indicate that DDE can be epoxidized by peroxides, and the resulting products are
able to form several adducts with 2'-deoxyadenosine and/or DNA. Endogenous DNA
adduct formation can contribute to the already reported high cytotoxicity of DDE
to mammalian cells.
PMID- 9760279
TI - Selectivity of polycyclic inhibitors for human cytochrome P450s 1A1, 1A2, and
1B1.
AB - Human cytochrome P450s 1A1, 1A2, and 1B1 are known to have overlapping substrate
specificities. All are regulated in part by the Ah locus; P450 1A2 is expressed
essentially only in liver, but P450s 1A1 and 1B1 are both expressed in many
extrahepatic tissues. Twenty-five polycyclic hydrocarbons, many containing
acetylenic side chains, were examined as inhibitors of the three enzymes using 7
ethoxyresorufin O-deethylation as the enzyme assay in all cases. Several
compounds were inhibitory at low nanomolar concentrations. 1-(1-Propynyl)pyrene
and 2-(1-propynyl)phenanthrene nearly completely inhibited P450 1A1 at
concentrations at which no P450 1B1 inhibition was observed. 2-Ethynylpyrene and
alpha-naphthoflavone (7, 8-benzoflavone) nearly completely inhibited P450 1B1 at
concentrations at which no P450 1A1 inhibition was noted. All four of the above
compounds also inhibited P450 1A2. Several polycyclic hydrocarbons devoid of
acetylenic groups were also inhibitory with respect to all three P450s. Some of
the acetylenic compounds examined showed enhanced inhibition following
preincubation with the P450s in the presence of cofactors NADPH and O2. However,
of seven compounds (five acetylenes) tested with P450 1B1, only two [2
ethynylpyrene and 4-(1-propynyl)biphenyl] showed such evidence for mechanism
based inactivation. We conclude that (i) several polycyclic hydrocarbons and
their oxidation products are very inhibitory with respect to human P450s 1A1,
1A2, and 1B1; (ii) of these inhibitors only some are mechanism-based
inactivators; and (iii) some of the inhibitors are potentially useful for
distinguishing between human P450s 1A1 and 1B1.
PMID- 9760280
TI - Synthesis and characterization of bay region halohydrins derived from
Benzo[a]pyrene diol epoxide and their role as intermediates in halide-catalyzed
cis adduct formation.
AB - The bay region epoxide of benzo[a]pyrene (anti-BPDE) alkylates DNA to form
adducts with >98% trans stereochemistry. Halide ions catalyze this reaction;
however, this pathway is characterized by the formation of adducts with altered
cis stereochemistry. Bay region halohydrins are possible intermediates in these
reactions, but are too unstable to be isolated from aqueous solutions. However,
we successfully synthesized halohydrins in tetrahydrofuran (THF) by treatment of
anti-BPDE with the corresponding lithium halide salt in the presence of acetic
acid. Absorbance and CD spectroscopy clearly indicated the formation of chloro-,
bromo-, and iodohydrins. The structure and stereochemistry of the chlorohydrin
was established by NMR. Chloride addition is exclusively at the benzylic position
of the epoxide, and the stereochemistry of the C-9 and -10 positions is trans.
The long-wavelength absorbance band in the chloro-, bromo-, and iodohydrin is red
shifted 7, 13, and 22 nm, respectively, relative to the hydrolysis product of
anti-BPDE. The ellipticity of the same absorbance band in CD spectra of
enantiomerically pure halohydrins is opposite in sign compared to that of the
corresponding anti-BPDE enantiomer. The relative stability of these derivatives
is chlorohydrin > bromohydrin > iodohydrin. The chloro- and bromohydrins were
isolated, but the iodohydrin decomposed during this manipulation. The addition of
500 mM chloride decreased the hydrolysis rate of the chlorohydrin 4-fold in 50%
THF/buffer. Direct evidence for the transient formation of the iodohydrin in
aqueous buffer/acetone mixtures was obtained by absorbance spectroscopy. At 1 M
chloride, bromide, and iodide, alkylation of deoxyadenosine by anti-BPDE in
aqueous buffer yields 85, 91, and 92% cis adducts, respectively. In the absence
of halide, alkylation of deoxyadenosine in buffer by anti-BPDE, the chlorohydrin,
and the bromohydrin yields 32, 65, and 83% cis adducts, respectively.
PMID- 9760281
TI - Peroxynitrite-mediated nitration of tyrosine and inactivation of the catalytic
activity of cytochrome P450 2B1.
AB - The addition of peroxynitrite to purified cytochrome P450 2B1 resulted in a
concentration-dependent loss of the NADPH- and reductase-supported or tert
butylhydroperoxide-supported 7-ethoxy-4-(trifluoromethyl)coumarin O-deethylation
activity of P450 2B1 with IC50 values of 39 and 210 microM, respectively. After
incubation of P450 2B1 with 300 microM peroxynitrite, the heme moiety was not
altered, but the apoprotein was modified as shown by HPLC and spectral analysis.
Western blot analysis of peroxynitrite-treated P450 2B1 demonstrated the presence
of an extensive immunoreactivite band after incubating with anti-nitrotyrosine
antibody. However, the immunostaining was completely abolished after coincubation
of the anti-nitrotyrosine antibody with 10 mM nitrotyrosine. These results
indicated that one or more of the tyrosine residues in P450 2B1 were modified to
nitrotyrosines. The decrease in the enzymatic activity correlated with the
increase in the extent of tyrosine nitration. Further demonstration of tyrosine
nitration was confirmed by GC/MS analysis by using 13C-labeled tyrosine and
nitrotyrosine as internal standards; approximately 0.97 mol of nitrotyrosine per
mole of P450 2B1 was found after treatment with peroxynitrite. The peroxynitrite
treated P450 2B1 was digested with Lys C, and the resulting peptides were
separated by Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis
(SDS-PAGE). The amino acid sequence of the major nitrotyrosine-containing peptide
corresponded to a peptide containing amino acid residues 160-225 of P450 2B1,
which contains two tyrosine residues. Thus, incubation of P450 2B1 with
peroxynitrite resulted in the nitration of tyrosines at either residue 190 or 203
or at both residues of P450 2B1 concomitant with a loss of 2B1-dependent
activity.
PMID- 9760282
TI - In vitro inhibition of thyroid hormone sulfation by hydroxylated metabolites of
halogenated aromatic hydrocarbons.
AB - Earlier studies in our laboratory showed that hydroxylated metabolites of
polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), and dibenzofurans
(PCDFs) competitively inhibit thyroxine (T4) binding to transthyretin (TTR) and
type I deiodinase (D1) activity. In this study, we investigated the possible
inhibitory effects of hydroxylated metabolites of polyhalogenated aromatic
hydrocarbons (PHAHs) on iodothyronine sulfotransferase activity. Rat liver
cytosol was used as a source of sulfotransferase enzyme in an in vitro assay with
125I-labeled 3,3'-diiodothyronine (T2) as a model substrate. Increasing amounts
of hydroxylated PCBs, PCDDs, or PCDFs or extracts from incubation mixtures of
PHAHs and induced liver microsomes were added as potential inhibitors of T2
sulfotransferase activity. Hydroxylated metabolites of PCBs, PCDDs, and PCDFs
were found to be potent inhibitors of T2 sulfotransferase activity in vitro with
IC50 values in the low micromolar range (0.2-3.8 microM). The most potent
inhibitor of T2 sulfotransferase activity in our experiments was the PCB
metabolite 3-hydroxy-2,3',4, 4',5-pentachlorobiphenyl with an IC50 value of 0.2
microM. A hydroxyl group in the para or meta position appeared to be an important
structural requirement for T2 sulfotransferase inhibition by PCB metabolites.
Ortho hydroxy PCBs were much less potent, and none of the parent PHAHs was
capable of inhibiting T2 sulfotransferase activity. In addition, the formation of
T2 sulfotransferase-inhibiting metabolites of individual brominated diphenyl
ethers and nitrofen as well as from some commercial PHAH mixtures (e.g., Bromkal,
Clophen A50, and Aroclor 1254) was also demonstrated. These results indicate that
hydroxylated PHAHs are potent inhibitors of thyroid hormone sulfation. Since
thyroid hormone sulfation may play an important role in regulating free hormone
levels in the fetus, and PCB metabolites are known to accumulate in fetal tissues
after maternal exposure to PCBs, these observations may have implications for
fetal thyroid hormone homeostasis and development.
PMID- 9760283
TI - Chlorothioketene, the ultimate reactive intermediate formed by cysteine conjugate
beta-lyase-mediated cleavage of the trichloroethene metabolite S-(1,2
Dichlorovinyl)-L-cysteine, forms cytosine adducts in organic solvents, but not in
aqueous solution.
AB - Chlorothioketene has been suggested as a reactive intermediate formed by the
cysteine conjugate beta-lyase-mediated cleavage of S-(1,2-dichlorovinyl)-L
cysteine, a minor metabolite of trichloroethene. Halothioketenes are highly
reactive, and their intermediate formation may be confirmed by reactions such as
cycloadditions and thioacylations of nucleophiles. A precursor of
chlorothioketene, S-(1,2-dichlorovinyl)thioacetate, is readly accessible by the
reaction of dichloroethyne with thioacetic acid. In presence of base, S-(1,2
dichlorovinyl)thioacetate is cleaved to chlorothioketene. Chlorothioketene is not
stable at room temperature and was characterized after transformation to stable
products by reaction with compounds such as cyclopentadiene, N,N-diethylamine,
and ethanol. In organic solvents, the cleavage of S-(1, 2
dichlorovinyl)thioacetate in the presence of cytosine results in N4
acetylcytosine, N4-(chlorothioacetyl)cytosine, and small amounts of 3-(N4
thioacetyl)cytosine. No reaction products were seen with guanosine, adenosine,
and thymidine under identical conditions. When cytosine was reacted with S-(1,2
dichlorovinyl)thioacetate in aqueous solutions, only N4-acetylcytosine was
formed. N4-(Chlorothioacetyl)cytosine and 3-(N4-thioacetyl)cytosine were not
detected even when using a very sensitive method, derivatization with
pentafluorobenzyl bromide and electron capture mass spectrometry with a detection
limit of 50 fmol/microliter of injection volume. Aqueous solutions of DNA cleave
S-(1, 2-dichlorovinyl)thioacetate to give N4-acetyldeoxycytidine in DNA, but
chlorothioketene adducts of deoxynucleosides were also not detected in these
experiments. These results confirm the electrophilic reactivity of
chlorothioketene toward nucleophilic groups of DNA constituents in inert solvents
but also demonstrate that the formation of DNA adducts under physiological
conditions likely is not efficient. Therefore, DNA adducts may not represent
useful biomarkers of exposure and biochemical effects for trichloroethene.
PMID- 9760284
TI - DNA damage by tert-butoxyl radicals generated in the photolysis of a water
soluble, DNA-binding peroxyester acting as a radical source.
AB - The photolysis of the water-soluble perester 1 leads to tert-butoxyl radicals as
confirmed by EPR studies with the spin trap 5, 5-dimethylpyrroline N-oxide
(DMPO). In the presence of DNA, oxidative cleavage of the latter was demonstrated
by the formation of strand breaks in supercoiled pBR 322 DNA and by a substantial
decrease of the melting temperature of salmon testes DNA. Guanidine, released
from, for example, oxazolone and oxoimidazolidine on base treatment, was observed
with calf thymus DNA and 2'-deoxyguanosine. These DNA modifications were
effectively inhibited by the radical scavenger di-tert-butylcresol or the
hydrogen atom donor glutathione. Photosensitization by the arene chromophore was
excluded since the corresponding ester 2 caused no DNA damage, nor were the
photoproducts of the perester 1 active. The efficacy of the perester 1 in
oxidizing DNA derives from the fact that the tert-butoxyl radicals are
photolytically generated in the immediate vicinity of the DNA, due to
electrostatic binding of the cationic perester to the DNA, as confirmed by
fluorescence measurements. These results demonstrate that the photolysis of
perester 1 provides a suitable source of tert-butoxyl radicals in aqueous media,
a necessary prerequisite for biochemical investigations.
PMID- 9760285
TI - Mechanism for inhibition of thyroid peroxidase by leucomalachite green.
AB - The triphenylmethane dye, malachite green (MG), is used to treat and prevent
fungal and parasitic infections in the aquaculture industry. It has been reported
that the reduced metabolite of MG, leucomalachite green (LMG), accumulates in the
tissues of fish treated with MG. MG is structurally related to other
triphenylmethane dyes (e.g., gentian violet and pararosaniline) that are
carcinogenic in the liver, thyroid, and other organs of experimental animals. The
ability of LMG to inhibit thyroid peroxidase (TPO), the enzyme that catalyzes the
iodination and coupling reactions required for thyroid hormone synthesis, was
determined in this study. LMG inhibited TPO-catalyzed tyrosine iodination (half
maximal inhibition at ca. 10 microM). LMG also inhibited the TPO-catalyzed
formation of thyroxine in low-iodine human goiter thyroglobulin (half-maximal
inhibition at ca. 10 microM) using a model system that measures simultaneous
iodination and coupling. Direct inhibition of the coupling reaction by LMG was
shown using a coupling-only system containing chemically preiodinated
thyroglobulin as the substrate. Incubation of LMG with TPO, iodide, and tyrosine
in the presence of a H2O2-generating system yielded oxidation products that were
identified by using on-line LC/APCI-MS as desmethyl LMG, 2desmethyl LMG,
3desmethyl LMG, MG, and MG N-oxide. Similar products from LMG were observed in
incubations with TPO and H2O2 alone. These findings suggest that the anti-thyroid
effects (increased serum thyroid-stimulating hormone and decreased serum
thyroxine) observed in rats treated with LMG result from blockade of hormone
synthesis through alternate substrate inhibition and that chronic exposure could
cause thyroid follicular cell tumors through a hormonal mechanism. The observed
TPO-catalyzed oxidative demethylation of LMG to a primary arylamine also suggests
a genotoxic mechanism for tumor formation is possible.
PMID- 9760286
TI - The equine estrogen metabolite 4-hydroxyequilenin causes DNA single-strand breaks
and oxidation of DNA bases in vitro.
AB - Premarin (Wyeth-Ayerst) is the estrogen replacement treatment of choice and
continues to be one of the most widely dispensed prescriptions in North America.
In addition to endogenous estrogens, Premarin contains unsaturated equine
estrogens, including equilenin [1,3,5(10),6,8-estrapentaen-3-ol-17-one]. In
previous work, we showed that the equilenin metabolite 4-hydroxyequilenin (4
OHEN) can be autoxidized to 4-OHEN-o-quinone which readily entered into a redox
couple with the semiquinone radical catalyzed by NAD(P)H, P450 reductase, or
quinone reductase, resulting in generation of reactive oxygen species [Shen, L.,
Pisha, E., Huang, Z., Pezzuto, J. M., Krol, E., Alam, Z., van Breemen, R. B., and
Bolton, J. L. (1997) Carcinogenesis 18, 1093-1101]. As oxidative damage to DNA by
reactive oxygen species generated by redox active compounds has been proposed to
lead to tumor formation, we investigated whether 4-OHEN could cause DNA damage.
We treated lambda phage DNA with 4-OHEN and found that extensive single-strand
breaks could be obtained with increasing concentrations of 4-OHEN as well as
increasing incubation times. If scavengers of reactive oxygen species are
included in the incubations, DNA could be completely protected from 4-OHEN
mediated damage. In contrast, NADH and CuCl2 enhanced the ability of 4-OHEN to
cause DNA single-strand breaks presumably due to redox cycling between 4-OHEN and
the semiquinone radical generating hydrogen peroxide and ultimately copper
peroxide complexes. We also confirmed that 4-OHEN could oxidize DNA bases since
hydrolysis of 4-OHEN-treated calf thymus DNA and HPLC separation with
electrospray MS detection revealed oxidized deoxynucleosides, including 8
oxodeoxyguanosine and 8-oxodeoxyadenosine. Our data suggest that DNA single
strand breaks and oxidation of DNA bases by 4-OHEN could contribute to the
carcinogenic mechanism(s) of equine estrogens.
PMID- 9760287
TI - Modes of myocardial cell injury and cell death in ischemic heart disease.
PMID- 9760288
TI - Reduction of recurrent ischemia with abciximab during continuous ECG-ischemia
monitoring in patients with unstable angina refractory to standard treatment
(CAPTURE).
AB - BACKGROUND: In the CAPTURE (c7E3 Fab Anti Platelet Therapy in Unstable REfractory
angina) trial, 1265 patients with refractory unstable angina were treated with
abciximab or placebo, in addition to standard treatment from 16 to 24 hours
preceding coronary intervention through 1 hour after intervention. To investigate
the incidence of recurrent ischemia and the ischemic burden, a subset of 332
patients (26%) underwent continuous vector-derived 12-lead ECG-ischemia
monitoring. METHODS AND RESULTS: Patients were monitored from start of treatment
through 6 hours after coronary intervention. Ischemic episodes were detected in
31 (18%) of the 169 abciximab and in 37 (23%) of the 163 placebo patients (NS).
Only 9 (5%) of abciximab versus 22 (14%) of placebo patients had >/=2 ST episodes
(P<0.01). In patients with ischemia, abciximab significantly reduced total
ischemic burden (P<0.02), which was calculated alternatively as the total
duration of ST episodes per patient, the area under the curve of the ST vector
magnitude during episodes, or the sum of the areas under the curves of 12 leads
during episodes. Twenty-one patients (6%) suffered a myocardial infarction (MI)
(18) or died (3) within 5 days of treatment. The presence of asymptomatic and
symptomatic ST episodes during the monitoring period preceding coronary
intervention was associated with an increased relative risk of these events of
3.2 (95% CI 1.4, 7.4) and 4.1 (95% CI 1.4, 12.2), respectively. CONCLUSIONS:
Recurrent ischemia predicts MI or death within 5 days of follow-up. Treatment
with abciximab is associated with a reduction of frequent ischemia and a
reduction of total ischemic burden in patients with refractory unstable angina.
As such, patients with ischemia derive particularly high benefit from abciximab.
PMID- 9760289
TI - Risk profile and prediction of long-term ischemic stroke mortality: a 21-year
follow-up in the Israeli Ischemic Heart Disease (IIHD) Project.
AB - BACKGROUND: Multinational comparisons demonstrate marked ethnic and regional
variation in stroke mortality and risk-factor distribution. We assessed the role
of ethnicity and estimated the cumulative effect of multiple risk factors on long
term ischemic stroke mortality. METHODS AND RESULTS: Civil servants and municipal
employees in Israel (n=9734 men; age, >/=42 years), chosen by stratified sampling
in 6 prespecified areas of birth (those born in Israel and those who were
immigrants from 5 other regional-ethnic strata), were included in the Israeli
Ischemic Heart Disease (IIHD) Project. Over a 21-year follow-up period, age
adjusted mortality rates per 10 000 person-years attributed to ischemic stroke
(n=282; International Classification of Diseases [ICD]-9 codes 433 to 438) were
higher among immigrants to Israel from northern Africa and the Mideast (17.1 to
19.0), than from 3 parts of Europe (11.3 to 12.4). Crude rates per 1000 subjects
observed in those born in Asia or Africa (29.4 to 31.2) exceeded rates predicted
by risk-factor profiles (21.4 to 24.9). Adjusted hazard ratios were 3.00 for age
(per 10 years), 2.15 for left ventricular hypertrophy, 1.69 for systolic blood
pressure (BP, per 20 mm Hg), 1.86 for diabetes mellitus, 1.83 for peripheral
vascular disease, 1.79 for smoking (>20 cigarettes per day), 1.51 for coronary
heart disease, 1.16 for percent cholesterol contained in the HDL fraction (%HDL,
per 5% decrease), and 1.88 for diastolic BP (per 12 mm Hg; assessed in an
alternative model). Accounting for regression dilution bias and assessed from
repeat measurements, we found that hazard ratio estimates associated with
diastolic BP, systolic BP, and percent HDL (per increments described) increased
to 3.22, 2.23, and 1.23, respectively. Ischemic stroke mortality rates were 30
fold greater among subjects at the highest versus the lowest quintile of
predicted probability according to risk-factor profiles (81.2 versus 2.6 per 1000
subjects). CONCLUSIONS: Assessment of multiple risk factors provides useful
quantitative prediction of long-term ischemic stroke mortality risk. Regional
ethnic variations are consistent with a hypothesis that other, undetermined
inherent genetic or sociocultural factors act to increase ischemic stroke
mortality rates in immigrants to Israel from the Mideast and northern Africa over
that predicted by conventional risk factors.
PMID- 9760290
TI - S-nitrosoglutathione reduces the rate of embolization in humans.
AB - BACKGROUND: Antiplatelet agents presently used in the secondary prevention of
cardiovascular disease fail to prevent the majority of cases of recurrent stroke
and systemic embolization. An evaluation of the efficacy of new agents is
hampered by a lack of in vivo models in humans. Asymptomatic cerebral embolic
signals (ES) may be detected with the use of transcranial Doppler
ultrasonography. These signals are particularly common after carotid
endarterectomy, and this provides a situation in which new antiplatelet agents
can be evaluated. With this model, we determined the effectiveness of S
nitrosoglutathione (GSNO), a nitric oxide donor with relative platelet
specificity, in reducing cerebral embolization. METHODS AND RESULTS: Transcranial
Doppler ultrasound recordings from the ipsilateral middle cerebral artery were
made after carotid endarterectomy in 12 control patients and 12 patients
receiving intravenous GSNO from the induction of anesthesia until 2 hours after
skin closure. Recording times were 0.5 to 3.5, 6 to 7, and 24 to 25 hours after
skin closure. The Doppler signal was recorded onto tape, and analysis for ES was
performed, with the investigators blinded to treatment group. All patients
received aspirin 300 mg/d before surgery and 5000 IU of heparin during surgery.
The median (range) number of ES detected during the initial 3-hour postoperative
recording was markedly reduced in the GSNO group compared with the control group:
7.5 (0 to 61) versus 38.5 (1 to 219) (P=0.018). This difference persisted until 6
hours after surgery. CONCLUSIONS: Despite the administration of aspirin and
heparin, frequent embolization occurred and was markedly reduced after the
administration of GSNO. This demonstrates the potential use of platelet-specific
nitric oxide donors in the treatment of thromboembolic disease. This model of
cerebral embolism may allow determination of the effectiveness of new
antiplatelet agents in humans.
PMID- 9760291
TI - Prediction of 30-day mortality among patients with thrombolysis-related
intracranial hemorrhage.
AB - BACKGROUND: Limited information exists on risk factors for mortality after
thrombolysis-related intracranial hemorrhage. We wished to determine the
characteristics associated with 30-day mortality after thrombolysis-related
intracranial hemorrhage. METHODS AND RESULTS: We performed an observational
analysis within a randomized trial of 4 thrombolytic therapies, conducted in 1081
hospitals in 15 countries. Patients presented with ST-segment elevation within 6
hours of symptom onset. Our population was composed of the 268 patients who had
primary intracranial hemorrhage after thrombolysis. With univariable and
multivariable analyses, we identified clinical and brain imaging characteristics
that would predict 30-day mortality among these patients. CT or MRI were
available for 240 patients (90%). The 30-day mortality rate was 59.7%. Glasgow
Coma Scale score, age, time from thrombolysis to symptoms of intracranial
hemorrhage, hydrocephalus, herniation, mass effect, intraventricular extension,
and volume and location of intracranial hemorrhage were significant univariable
predictors. Multivariable analysis of 170 patients with complete data, 98 of whom
died, identified the following independent, significant predictors: Glasgow Coma
Scale score (chi2, 19.3; P<0. 001), time from thrombolysis to intracranial
hemorrhage (chi2, 15.8; P<0.001), volume of intracranial hemorrhage (chi2, 11.6;
P<0.001), and baseline clinical predictors of mortality in the overall GUSTO-I
trial (chi2, 10.3; P=0.001). The final model had a C-index of 0.931. CONCLUSIONS:
This model provides excellent discrimination between patients who are likely to
live and those who are likely to die after thrombolytic-related intracranial
hemorrhage; this may aid in making decisions about the appropriate level of care
for such patients.
PMID- 9760292
TI - Molecular basis of transient outward potassium current downregulation in human
heart failure: a decrease in Kv4.3 mRNA correlates with a reduction in current
density.
AB - BACKGROUND: Despite advances in medical therapy, congestive heart failure remains
a major cause of death in the developed world. A disproportionate number of the
deaths of patients with heart failure are sudden and presumed to be arrhythmic.
Heart failure in humans and in animal models is associated with prolongation of
the action potential duration (APD), the result of downregulation of K+ currents
prominently, the Ca2+-independent transient outward current (Ito). The mechanism
for the reduction of Ito in heart failure is unknown. The K+ channel alpha
subunit Kv4.3, a homolog of the Drosophila Shal family, is most likely to encode
all or part of the native cardiac Ito in humans. METHODS AND RESULTS: We used
ribonuclease protection assays and whole-cell electrophysiological recording to
study changes in the level of Kv4.3 mRNA and Ito in human tissues and isolated
ventricular myocytes, respectively. We found that the level of Kv4.3 mRNA
decreased by 30% in failing hearts compared with nonfailing controls.
Furthermore, this reduction correlated with the reduction in peak Ito density
measured in ventricular myocytes isolated from adjacent regions of the heart.
There was no significant change in the steady-state level of any other mRNA
studied (HERG, Kv1.4, Kir2.1, Kvss1.3, and the alpha1C subunit of the Ca2+
channel). mRNAs encoding Kv1.2, Kv1.5, and Kv2.1 were found in low abundance in
human ventricle. CONCLUSIONS: These data provide further support for the
hypothesis that Kv4.3 encodes all or part of the native cardiac Ito in humans and
that part of the downregulation of this current in heart failure may be
transcriptionally regulated.
PMID- 9760293
TI - Central vagotonic effects of atropine modulate spectral oscillations of
sympathetic nerve activity.
AB - BACKGROUND: Low-dose atropine causes bradycardia either by acting on the
sinoatrial node or by its effects on central muscarinic receptors increasing
vagal activity. Any central muscarinic effects of high-dose atropine on RR
interval are masked by peripheral muscarinic blockade at the sinoatrial node,
which causes tachycardia. Effects of central parasympathetic activation on
sympathetic activity are not known. METHODS AND RESULTS: Using power spectral
analysis of RR interval, intra-arterial blood pressure, respiration, and muscle
sympathetic nerve activity (MSNA), we examined the effects of both low (2
microgram/kg IV) and high (15 microgram/kg IV) doses of atropine. After low-dose
atropine, RR increased by 9+/-1% (P<0.0001), the low-frequency (LF) component (in
normalized units, NU) of RR variability decreased by -32+/-8%, and the high
frequency (HF)NU component increased (+74+/-19%); hence, LF/HF of RR variability
fell by 52+/-10% (all P<0.01). Although overall MSNA did not change, LFNU of MSNA
decreased (-15+/-5%), HFNU of MSNA increased (+31+/-3%), and LF/HF of MSNA fell (
41+/-8%) (all P<0.01). After high-dose atropine, LFNU of MSNA decreased (-17+/
12%), HFNU of MSNA increased (+22+/-3%), and LF/HF of MSNA fell (-51+/-21%) (all
P<0.02). CONCLUSIONS: Increasing central parasympathetic activity with low-dose
atropine is associated with an increase in the HF and a decrease in the LF
oscillations of both RR interval and MSNA variability. High-dose atropine
similarly induces an increase in the HF and a decrease in the LF components of
MSNA variability. Thus, central parasympathetic activation is able to modulate
the oscillatory characteristics of sympathetic nerve traffic to peripheral blood
vessels.
PMID- 9760294
TI - Dysfunctional voltage-gated K+ channels in pulmonary artery smooth muscle cells
of patients with primary pulmonary hypertension.
AB - BACKGROUND: Primary pulmonary hypertension (PPH) is a rare disease of unknown
cause. Although PPH and secondary pulmonary hypertension (SPH) share many
clinical and pathological characteristics, their origins may be disparate. In
pulmonary artery smooth muscle cells (PASMCs), the activity of voltage-gated K+
(KV) channels governs membrane potential (Em) and regulates cytosolic free Ca2+
concentration ([Ca2+]cyt). A rise in [Ca2+]cyt is a trigger of vasoconstriction
and a stimulus of smooth muscle proliferation. METHODS AND RESULTS: Fluorescence
microscopy and patch clamp techniques were used to measure [Ca2+]cyt, Em, and KV
currents in PASMCs. Mean pulmonary arterial pressures were comparable (46+/-4 and
53+/-4 mm Hg; P=0.30) in SPH and PPH patients. However, PPH-PASMCs had a higher
resting [Ca2+]cyt than cells from patients with SPH and nonpulmonary hypertension
disease. Consistently, PPH-PASMCs had a more depolarized Em than SPH-PASMCs.
Furthermore, KV currents were significantly diminished in PPH-PASMCs. Because of
the dysfunctional KV channels, the response of [Ca2+]cyt to the KV channel
blocker 4-aminopyridine was significantly attenuated in PPH-PASMCs, whereas the
response to 60 mmol/L K+ was comparable to that in SPH-PASMCs. CONCLUSIONS: These
results indicate that KV channel function in PPH-PASMCs is inhibited compared
with SPH-PASMCs. The resulting membrane depolarization and increase in [Ca2+]cyt
lead to pulmonary vasoconstriction and PASMC proliferation. Our data suggest that
defects in PASMC KV channels in PPH patients may be a unique mechanism involved
in initiating and maintaining pulmonary vasoconstriction and appear to play a
role in the pathogenesis of PPH.
PMID- 9760295
TI - Estimation of oxygen delivery in newborns with a univentricular circulation.
AB - BACKGROUND: The management of neonates with complex congenital anomalies depends
on careful interpretation of arterial blood gas values. Improved interpretation
of these oxygen parameters may allow clinicians to avoid unexpected
cardiovascular events. This study examined whether systemic oxygen delivery (DO2)
can be maximized by the use of indices derived from oxygen saturation
measurements in neonates with hypoplastic left heart syndrome. METHODS AND
RESULTS: For the single-ventricle heart with both circulations in parallel, we
used a previously developed computer simulation to obtain DO2 as a function of
systemic arterial (SaO2) and venous (SvO2) oxygen saturation, arteriovenous
oxygen difference (Sa-vO2), or pulmonary-to-systemic flow ratio (Qp/Qs). We also
examined the oxygen excess factor, SaO2/Sa-vO2 (Omega). We found that (1) slight
increases in SaO2 may be associated with large decreases in DO2. (2) Low values
for SvO2 indicate low values for DO2. (3) Curves for Sa-vO2 and Qp/Qs are
redundant in the data provided. (Qp/Qs, however, provides these data in more
physiologically relevant terms.) (4) High values for Qp/Qs (>4) are associated
with low DO2. (5) Estimating Qp/Qs from oxygen saturation measurements may result
in errors when pulmonary venous oxygen saturation is not available. (6)
Maximizing DO2 is extremely difficult using SaO2, SvO2, and Qp/Qs. (7) A linear
relationship exists between Omega and DO2, and this linear relationship is not
altered by changes in cardiac output. CONCLUSIONS: Patients with low SvO2 values
require attention. Ideally, after reducing Qp/Qs to <1.5, Omega might be a better
index to guide further therapy and maximize DO2. Interventions that increased
Omega would be considered beneficial, whereas interventions that decreased Omega
would be considered detrimental.
PMID- 9760296
TI - Whole-body hyperthermia provides biphasic cardioprotection against
ischemia/reperfusion injury in the rat.
AB - BACKGROUND: Hyperthermia increases cardiac tolerance to ischemia/reperfusion
injury 24 hours after the heat stress. Free radicals and redox mechanisms have
been implicated in such tolerance. However, the time course and its relation to
the induction of antioxidative enzymes in the protection induced by whole-body
hyperthermia against ischemia/reperfusion injury are unknown. METHODS AND
RESULTS: Hyperthermia was induced in anesthetized rats by placement in a
temperature-controlled water bath. After the defined recovery interval(s) at room
temperature, ischemia was induced by occlusion of the left coronary artery for 20
minutes, followed by reperfusion for 48 hours. The exposure to hyperthermia led
to a recovery interval- dependent, biphasic reduction in the incidence of
ventricular fibrillation during ischemia and in the size of the myocardial
infarct as determined after 48 hours of reperfusion. The time course of the late
phase (24- to 96-hour recovery interval) but not the early-phase (0.5 hour)
cardioprotection depended on the degree of hyperthermia. The time course of the
increase in myocardial manganese superoxide dismutase (Mn-SOD) activity
corresponded to that of the cardioprotective effects, although an increase in the
content of Mn-SOD and of heat shock protein 72 corresponded only to the late
phase effects. Administration of an antioxidant before hyperthermia abolished the
early- and late-phase cardioprotection and the increase in Mn-SOD activity.
CONCLUSIONS: THe activation of Mn-SOD mediated by free radical production during
hyperthermia is important in the acquisition of early-phase and late-phase
cardioprotection against ischemia/reperfusion injury in rats.
PMID- 9760297
TI - "Apoptotic" myocytes in infarct area in rabbit hearts may be oncotic myocytes
with DNA fragmentation: analysis by immunogold electron microscopy combined with
In situ nick end-labeling.
AB - BACKGROUND: Modes of cell death have been defined morphologically as apoptosis
and oncosis. Infarcted myocytes have been reported to show apoptosis, as revealed
by DNA fragmentation by DNA ladder and by in situ terminal deoxynucleotidyl
transferase-mediated dUTP nick end-labeling (TUNEL) at the light microscopic
level. We investigated whether TUNEL-positive infarcted myocytes have apoptotic
or oncotic ultrastructures by using electron microscopic TUNEL, which can
simultaneously observe the ultrastructure and DNA fragmentation of the same
myocytes. METHODS AND RESULTS: Thirty rabbits were divided into 5 groups (n=6
each) that were subjected to a sham operation or to 30-minute ischemia followed
by 0-minute, 30-minute, 2-hour, or 4-hour reperfusion of a coronary artery. In
the 2- and 4-hour reperfusion groups only, DNA electrophoresis showed a ladder
pattern, and the light microscopic TUNEL finding was positive in the nuclei of
myocytes localized in the infarcted area (6+/-2% and 11+/-3%, respectively).
Electron microscopic TUNEL showed that nuclei with a significant accumulation of
immunogold particles (indicating an electronic microscopic TUNEL-positive result)
were observed only in the infarcted myocytes with irreversibly oncotic
ultrastructures that were found in the hearts of the 2- and 4-hour reperfusion
groups (41+/-3% and 83+/-4%, respectively). Irreversibly oncotic myocytes
(indicated by swelling, inhomogeneously clumped chromatin in nuclei, dense bodies
in mitochondria, and/or ruptured plasma membranes) were also seen in the 0- and
30-minute reperfusion groups, which did not exhibit TUNEL-positive myocytes.
There was no evidence of apoptotic ultrastructures in the myocytes. CONCLUSIONS:
DNA fragmentation occurs in the myocytes that had already shown irreversibly
oncotic, but not apoptotic, ultrastructures with ischemia and/or reperfusion.
Therefore, DNA fragmentation itself does not always mean apoptosis, and so-called
apoptotic infarcted myocytes may belong to a category of cell death other than
apoptosis.
PMID- 9760298
TI - Effect of platelet activation on coronary collateral blood flow.
AB - BACKGROUND: The platelet products thromboxane A2 and serotonin have been shown to
cause constriction of well-developed coronary collateral vessels. This study was
performed to determine whether intravascular platelet activation produced with
platelet activating factor (PAF) can cause a decrease in coronary collateral
blood flow. METHODS AND RESULTS: Collateral vessel growth was induced by
embolization of a hollow stainless steel plug into the left anterior descending
coronary artery (LAD) of adult dogs. The animals were returned to the laboratory
3 to 6 weeks later for surgical instrumentation and measurement of collateral
blood flow. Collateral flow was assessed by measuring retrograde blood flow from
the cannulated collateral-dependent artery. PAF (10 nmol) was injected into the
left main coronary artery to allow products of platelet activation to reach
collateral vessels arising from the left coronary system. PAF caused a
vasoconstrictor response, which became maximal 3 minutes after injection and
resulted in a 40.3+/-7.4% decrease in retrograde blood flow (32.1+/-2.1 to 19.6+/
3.2 mL/min; P<0.05). By 15 minutes after the PAF injection, both retrograde blood
flow and transcollateral resistance had returned to normal. After pretreatment
with the thromboxane A2 receptor antagonist SQ30, 741, the vasoconstrictor
response to PAF was abolished and, in contrast to the decrease in retrograde
blood flow from PAF alone, a weak vasodilator effect was unmasked. CONCLUSIONS:
PAF caused a decrease in coronary collateral blood flow. This vasoconstrictor
response required the participation of thromboxane A2.
PMID- 9760299
TI - Gene therapy with extracellular superoxide dismutase attenuates myocardial
stunning in conscious rabbits.
AB - BACKGROUND: Administration of Cu/Zn superoxide dismutase (SOD) without catalase
fails to alleviate myocardial stunning, but extracellular SOD (Ec-SOD) may be
more effective because it binds to heparan sulfate proteoglycans on the cellular
glycocalyx. We therefore used in vivo gene transfer to increase systemic levels
of Ec-SOD and determined whether this gene therapy protects against myocardial
stunning. METHODS AND RESULTS: The cDNA for human Ec-SOD was cloned behind the
cytomegalovirus (CMV) promoter and incorporated into a replication-deficient
adenovirus (Ad5/CMV/Ec-SOD). Injection of this virus (2x10(8) pfu/kg IV) produced
high levels of Ec-SOD in the liver, which could be redistributed to the heart and
other organs by injection of heparin. Conscious rabbits underwent a sequence of
six 4-minute coronary occlusion/4-minute reperfusion cycles for 3 consecutive
days starting 3 days after intravenous injection of Ad5/CMV/Ec-SOD or
Ad5/CMV/nls/LacZ (negative control). Both groups were given heparin (2000 U/kg
IV) 2 hours before the first sequence of occlusions. The severity of myocardial
stunning was measured as the total deficit of LV wall thickening after the last
reperfusion. On day 1, the total deficit of wall thickening was markedly
decreased in Ad5/CMV/Ec-SOD rabbits versus controls and similar to that seen on
days 2 and 3 in controls. CONCLUSIONS: The results demonstrate that in vivo gene
transfer of the cDNA encoding Ec-SOD provides the heart with substantial
protection against myocardial stunning without the need for concomitant
administration of catalase. The present observations provide the basis for
controlling gene therapy at the posttranslational level and for simultaneously
protecting multiple organs from oxidant stress.
PMID- 9760300
TI - Lewis Atterbury Conner: appreciation and bibliography.
PMID- 9760301
TI - Progress in device technology.
PMID- 9760302
TI - Restrictive cardiomyopathy secondary to Fabry's disease.
PMID- 9760303
TI - Impact of laboratory molecular diagnosis on contemporary diagnostic criteria for
genetically transmitted cardiovascular diseases: hypertrophic cardiomyopathy,
long-QT syndrome, and marfan syndrome : A statement for healthcare professionals
from the councils on clinical cardiology, cardiovascular disease in the young,
and basic science, american heart association
PMID- 9760304
TI - Obesity : impact on cardiovascular disease
PMID- 9760305
TI - Comparison between the uptake of nitrous oxide and nitric oxide in the human
nose.
PMID- 9760306
TI - Comparison between the uptake of nitrous oxide and nitric oxide in the human
nose.
AB - The absorption of nitrous oxide (N2O) during unidirectional flow was compared
with the rate of uptake of nitric oxide (NO). At flow rates of 10, 20, and 60
ml/min from one nostril to the other, with the soft palate closed, the N2O
reached a steady-state rate of absorption in 5-15 min. The mean superficial
capillary blood flow (n = 5) calculated from solubility and the steady-state rate
of N2O absorption ranged from 13.3 to 15.9 ml/min. The relation between
absorption of N2O in the nose and capillary blood flow fits a ventilation
perfusion model used by others to describe uptake of inert, soluble gases in the
rat nose. By contrast, the rate of uptake of NO gas, which is chemically
reactive, is 25-31 times as great as predicted by just its blood-to-air partition
coefficient. Exogenous NO (16.9 parts/million) did not induce nasal vasodilation
as measured with laser Doppler and N2O absorption methods. The difference between
the measured rate of uptake of NO and the rate of uptake attributable to its
partition coefficient in blood at the rate of blood flow calculated from N2O
uptake is probably due to chemical reaction of NO in mucous secretions, nasal
tissues, and capillary blood.
PMID- 9760307
TI - Exertional fatigue, sleep loss, and negative energy balance increase
susceptibility to hypothermia.
AB - The purpose of this study was to determine how chronic exertional fatigue and
sleep deprivation coupled with negative energy balance affect thermoregulation
during cold exposure. Eight men wearing only shorts and socks sat quietly during
4-h cold air exposure (10 degreesC) immediately after (<2 h, A) they completed 61
days of strenuous military training (energy expenditure approximately 4,150
kcal/day, energy intake approximately 3,300 kcal/day, sleep approximately 4
h/day) and again after short (48 h, SR) and long (109 days, LR) recovery. Body
weight decreased 7.4 kg from before training to A, then increased 6.4 kg by SR,
with an additional 6.4 kg increase by LR. Body fat averaged 12% during A and SR
and increased to 21% during LR. Rectal temperature (Tre) was lower before and
during cold air exposure for A than for SR and LR. Tre declined during cold
exposure in A and SR but not LR. Mean weighted skin temperature (Tsk) during cold
exposure was higher in A and SR than in LR. Metabolic rate increased during all
cold exposures, but it was lower during A and LR than SR. The mean body
temperature (0.67 Tre + 0.33 Tsk) threshold for increasing metabolism was lower
during A than SR and LR. Thus chronic exertional fatigue and sleep loss, combined
with underfeeding, reduced tissue insulation and blunted metabolic heat
production, which compromised maintenance of body temperature. A short period of
rest, sleep, and refeeding restored the thermogenic response to cold, but thermal
balance in the cold remained compromised until after several weeks of recovery
when tissue insulation had been restored.
PMID- 9760308
TI - Increased GLUT-4 translocation mediates enhanced insulin sensitivity of muscle
glucose transport after exercise.
AB - The purpose of this study was to determine whether the increase in insulin
sensitivity of skeletal muscle glucose transport induced by a single bout of
exercise is mediated by enhanced translocation of the GLUT-4 glucose transporter
to the cell surface. The rate of 3-O-[3H]methyl-D-glucose transport stimulated by
a submaximally effective concentration of insulin (30 microU/ml) was
approximately twofold greater in the muscles studied 3.5 h after exercise than in
those of the sedentary controls (0.89 +/- 0.10 vs. 0.43 +/- 0.05 micromol . ml-1
. 10 min-1; means +/- SE for n = 6/group). GLUT-4 translocation was assessed by
using the ATB-[2-3H]BMPA exofacial photolabeling technique. Prior exercise
resulted in greater cell surface GLUT-4 labeling in response to submaximal
insulin treatment (5.36 +/- 0.45 dpm x 10(3)/g in exercised vs. 3.00 +/- 0.38 dpm
x 10(3)/g in sedentary group; n = 10/group) that closely mirrored the increase in
glucose transport activity. The signal generated by the insulin receptor, as
reflected in the extent of insulin receptor substrate-1 tyrosine phosphorylation,
was unchanged after the exercise. We conclude that the increase in muscle insulin
sensitivity of glucose transport after exercise is due to translocation of more
GLUT-4 to the cell surface and that this effect is not due to potentiation of
insulin-stimulated tyrosine phosphorylation.
PMID- 9760309
TI - Force heterogeneity in a two-dimensional network model of lung tissue elasticity.
AB - We have developed a model of forces developed in lung tissue in which the stress
bearing units are heterogeneous. Each element of the fiber network is composed of
an idealized elastin and collagen element in parallel. Elastin is represented by
linear springs and collagen by stiff strings that extend without resistance until
taut. The model can quantitatively account for the nonlinear shape of the length
tension curve of lung tissue strips when the knee lengths of the collagen fibers
are distributed according to an inverse power law. The novel feature of this
model is that as macroscopic strain increases the load is carried by
progressively fewer elements with progressively higher forces, and preferential
pathways of force transmission emerge within the matrix. The topology of these
self-organizing pathways of force transmission takes the rough appearance of
cracks, but, unlike real cracks, they represent the locus of force concentration
rather than force release.
PMID- 9760310
TI - Nonisometric behavior of fascicles during isometric contractions of a human
muscle.
AB - Fascicle length, pennation angle, and tendon elongation of the human tibialis
anterior were measured in vivo by ultrasonography. Subjects (n = 9) were
requested to develop isometric dorsiflexion torque gradually up to maximal at the
ankle joint angle of 20 degrees plantarflexion from the anatomic position.
Fascicle length shortened from 90 +/- 7 to 76 +/- 7 (SE) mm, pennation angle
increased from 10 +/- 1 to 12 +/- 1 degrees, and tendon elongation increased up
to 15 +/- 2 mm with graded force development up to maximum. The tendon stiffness
increased with increasing tendon force from 10 N/mm at 0-20 N to 32 N/mm at 240
260 N. Young's modulus increased from 157 MPa at 0-20 N to 530 MPa at 240-260 N.
It can be concluded that, in isometric contractions of a human muscle, mechanical
work, some of which is absorbed by the tendinous tissue, is generated by the
shortening of muscle fibers and that ultrasonography can be used to determine the
stiffness and Young's modulus for human tendons.
PMID- 9760311
TI - Expiratory flow limitation and intrinsic positive end-expiratory pressure in
obesity.
AB - Breathing at very low lung volumes might be affected by decreased expiratory
airflow and air trapping. Our purpose was to detect expiratory flow limitation
(EFL) and, as a consequence, intrinsic positive end-expiratory pressure (PEEPi)
in grossly obese subjects (OS). Eight OS with a mean body mass index (BMI) of 44
+/- 5 kg/m2 and six age-matched normal-weight control subjects (CS) were studied
in different body positions. Negative expiratory pressure (NEP) was used to
determine EFL. In contrast to CS, EFL was found in two of eight OS in the upright
position and in seven of eight OS in the supine position. Dynamic PEEPi and mean
transdiaphragmatic pressure (mean Pdi) were measured in all six CS and in six of
eight OS. In OS, PEEPi increased from 0.14 +/- 0.06 (SD) kPa in the upright
position to 0.41 +/- 0.11 kPa in the supine position (P < 0.05) and decreased to
0.20 +/- 0.08 kPa in the right lateral position (P < 0.05, compared with supine),
whereas, in CS, PEEPi was significantly smaller (<0.05 kPa) in each position. In
OS, mean Pdi in each position was significantly larger compared with CS. Mean Pdi
increased from 1.02 +/- 0.32 kPa in the upright position to 1.26 +/- 0.17 kPa in
the supine position (not significant) and decreased to 1. 06 +/- 0.26 kPa in the
right lateral position (P < 0.05, compared with supine), whereas there were no
significant changes in CS. We conclude that in OS 1) tidal breathing can be
affected by EFL and PEEPi; 2) EFL and PEEPi are promoted by the supine posture;
and 3) the increased diaphragmatic load in the supine position is, in part,
related to PEEPi.
PMID- 9760312
TI - Energy metabolism and interstitial fluid displacement in human gastrocnemius
during short ischemic cycles.
AB - Energy metabolism and interstitial fluid displacement were studied in the human
gastrocnemius during three subsequent 5-min ischemia-reperfusion periods
[ischemic preconditioning (IP)]. The muscle energy balance was assessed by
combining near-infrared spectroscopy (NIRS) and 31P-nuclear magnetic resonance
spectroscopy (31P-NMRS). The interstitial fluid displacement was determined by
combining NIRS and 23Na-NMRS. No changes in total energy consumption or in the
fractional contribution of the underlying energy sources (aerobic glycolysis,
anaerobic glycolysis, and Lohmann reaction) were observed in the muscle during
the tested IP protocol. Oxygen consumption in the muscle region of interest, as
estimated by NIRS, was approximately 8 micromol . 100 g-1 . min-1 and did not
change during IP. Phosphocreatine and ATP concentrations did not change over the
whole experimental period. A slight but significant (P < 0.05) increase in
intracellular pH was observed. Compared with the control, a 10% greater
interstitial fluid content per muscle unit volume was observed at the end of the
IP protocol. It is concluded that, at variance with cardiac muscle, repeated 5
min ischemia-reperfusion cycles do not induce metabolic changes in human
gastrocnemius but alter the interstitial fluid readjustment. The techniques
developed in the present study may be useful in identifying protocols suitable
for skeletal muscle preconditioning and to explain the functional basis of this
procedure.
PMID- 9760313
TI - Deposition and dispersion of 1-micrometer aerosol boluses in the human lung:
effect of micro- and hypergravity.
AB - We performed bolus inhalations of 1-micrometer particles in four subjects on the
ground (1 G) and during parabolic flights both in microgravity (microG) and in
approximately 1.6 G. Boluses of approximately 70 ml were inhaled at different
points in an inspiration from residual volume to 1 liter above functional
residual capacity. The volume of air inhaled after the bolus [the penetration
volume (Vp)] ranged from 200 to 1,500 ml. Aerosol concentration and flow rate
were continuously measured at the mouth. The deposition, dispersion, and position
of the bolus in the expired gas were calculated from these data. For Vp >/=400
ml, both deposition and dispersion increased with Vp and were strongly gravity
dependent, with the greatest deposition and dispersion occurring for the largest
G level. At Vp = 800 ml, deposition and dispersion increased from 33.9% and 319
ml in microG to 56.9% and 573 ml at approximately 1.6 G, respectively (P < 0.05).
At each G level, the bolus was expired at a smaller volume than Vp, and this
volume became smaller with increasing Vp. Although dispersion was lower in microG
than in 1 G and approximately 1.6 G, it still increased steadily with increasing
Vp, showing that nongravitational ventilatory inhomogeneity is partly responsible
for dispersion in the human lung.
PMID- 9760314
TI - Augmenting expiratory neuronal activity in sleep and wakefulness and in relation
to duration of expiration.
AB - Augmenting expiratory cells (n = 23) were recorded in the rostral medulla of five
cats in sleep and wakefulness. The objective was to determine the relationship of
their activity to the duration of expiration (TE) and, particularly, to TE in
rapid-eye-movement (REM) sleep, when expirations are short and may even cause
fractionated breathing. Correlation analysis (Kendall's tau) showed no consistent
relationship in any state between the breath-by-breath mean activity of
augmenting expiratory cells and TE. This result contradicts predications of an
inverse relationship between augmenting expiratory activity and TE. Some cells
(11 of 23) were more active in REM than in non-REM sleep and were active during
fractionated breathing. This suggests that fractionated breathing in REM sleep is
caused by short expiratory phases and not by intermittent inhibition of an
ongoing inspiration.
PMID- 9760316
TI - Genetic and other determinants of AMP deaminase activity in healthy adult
skeletal muscle.
AB - AMPD1 genotype, relative fiber type composition, training status, and gender were
evaluated as contributing factors to the reported variation in AMP deaminase
enzyme activity in healthy skeletal muscle. Multifactorial correlative analyses
demonstrate that AMPD1 genotype has the greatest effect on enzyme activity. An
AMPD1 mutant allele frequency of 13.7 and a 1.7% incidence of enzyme deficiency
was found across 175 healthy subjects. Homozygotes for the AMPD1 normal allele
have high enzyme activities, and heterozygotes display intermediate activities.
When examined according to genotype, other factors were found to affect
variability as follows: AMP deaminase activity in homozygotes for the normal
allele exhibits a negative correlation with the relative percentage of type I
fibers and training status. Conversely, residual AMP deaminase activity in
homozygotes for the mutant allele displays a positive correlation with the
relative percentage of type I fibers. Opposing correlations in different
homozygous AMPD1 genotypes are likely due to relative fiber-type differences in
the expression of AMPD1 and AMPD3 isoforms. Gender also contributes to variation
in total skeletal muscle AMP deaminase activity, with normal homozygous and
heterozygous women showing only 85-88% of the levels observed in genotype-matched
men.
PMID- 9760315
TI - Effects of hyperchloremia on blood oxygen binding in healthy calves.
AB - Three different levels of hyperchloremia were induced in healthy Friesian calves
to study the effects of chloride on blood oxygen transport. By infusion, the
calves received either 5 ml/kg of 0.9% NaCl (low-level hyperchloremia; group A),
5 ml/kg of 7.5% NaCl (moderate hyperchloremia; group B), or 7.5 ml/kg of 7.5%
NaCl (high-level hyperchloremia; group C). Blood was sampled from the jugular
vein and the brachial artery. Chloride concentration, hemoglobin content,
arterial and venous pH, PCO2, and PO2 were determined. At each time point (0, 15,
30, 60, and 120 min), the whole blood oxygen equilibrium curve (OEC) was measured
under standard conditions. In groups B and C, hyperchloremia was accompanied by a
sustained rightward shift of the OEC, as indicated by the significant increase in
the standard PO2 at 50% hemoglobin saturation. Infusion of hypertonic saline also
induced relative acidosis. The arterial and venous OEC were calculated, with body
temperature, pH, and PCO2 values in arterial and venous blood taken into account.
The degree of blood desaturation between the arterial and the venous compartments
[O2 exchange fraction (OEF%)] and the amount of oxygen released at tissue level
by 100 ml of bovine blood (OEF vol%) were calculated from the arterial and venous
OEC combined with the PO2 and hemoglobin concentration. The chloride-induced
rightward shift of the OEC was reinforced by the relative acidosis, but the
altered PO2 values combined with the lower hemoglobin concentration explained the
absence of any significant difference in OEF (% and vol%). We conclude that
infusion of hypertonic saline induces hyperchloremia and acidemia, which can
explain the OEC rightward shift observed in arterial and peripheral venous blood.
PMID- 9760317
TI - Differential responses to endurance training in subsarcolemmal and
intermyofibrillar mitochondria.
AB - To examine the effect of endurance training (6 wk of treadmill running) on
regional mitochondrial adaptations within skeletal muscle, subsarcolemmal (SS)
and intermyofibrillar (IMF) mitochondria were isolated from trained and control
rat hindlimb muscles. Mitochondrial oxygen consumption (VO2) was measured
polarographically by using the following substrates: 1 mM pyruvate + 1 mM malate
(P+M), 10 mM 2-oxoglutarate, 45 microM palmitoyl-DL-carnitine + 1 mM malate, and
10 mM glutamate. Spectrophotometric assays of cytochrome-c reductase and NAD
specific isocitrate dehydrogenase (IDH) activity were also performed. Maximal
(state III) and resting (state IV) VO2 were lower in SS than in IMF mitochondria
in both trained and control groups. In SS mitochondria, training elicited
significant 36 and 20% increases in state III VO2 with P+M and glutamate,
respectively. In IMF mitochondria, training resulted in a smaller (20%), yet
significant, increase in state III VO2 with P+M as a substrate, whereas state III
VO2 increased 33 and 27% with 2-oxoglutarate and palmitoyl-DL-carnitine + malate,
respectively. Within groups, cytochrome-c reductase and IDH activities were lower
in SS when compared with IMF mitochondria. Training increased succinate
cytochrome-c reductase in both SS (30%) and IMF mitochondria (28%). IDH activity
increased 32% in the trained IMF but remained unchanged in SS mitochondria. We
conclude that endurance training promotes substantial changes in protein
stoichiometry and composition of both SS and IMF mitochondria.
PMID- 9760318
TI - Patterned cardiovascular responses to sleep and nonrespiratory arousals in a
porcine model.
AB - Patients with obstructive sleep apnea experience marked cardiovascular changes
with apnea termination. Based on this observation, we hypothesized that sudden
sleep disruption is accompanied by a specific, patterned hemodynamic response,
similar to the cardiovascular defense reaction. To test this hypothesis, we
recorded mean arterial blood pressure, heart rate, iliac blood flow and vascular
resistance, and renal blood flow and vascular resistance in five pigs
instrumented with chronic sleep electrodes. Cardiovascular parameters were
recorded during quiet wakefulness, during non-rapid-eye-movement and rapid-eye
movement sleep, and during spontaneous and induced arousals. Iliac vasodilation
(iliac vascular resistance decreased by -29.6 +/- 4.1% of baseline) associated
with renal vasoconstriction (renal vascular resistance increased by 10.3 +/-
4.0%), tachycardia (heart rate increase: +23.8 +/- 3.1%), and minimal changes in
mean arterial blood pressure were the most common pattern of arousal response,
but other hemodynamic patterns were observed. Similar findings were obtained in
rapid-eye-movement sleep and for acoustic and tactile arousals. In conclusion,
spontaneous and induced arousals from sleep may be associated with simultaneous
visceral vasoconstriction and hindlimb vasodilation, but the response is
variable.
PMID- 9760319
TI - Superoxide dismutase restores endothelium-dependent arteriolar dilatation during
acute infusion of nicotine.
AB - We previously showed [Am. J. Physiol. 272 (Heart Circ. Physiol. 41): H2337-H2342,
1997] that nicotine impairs endothelium-dependent arteriolar dilatation. However,
mechanisms that accounted for the effect of nicotine on endothelium-dependent
vasodilatation were not examined. Thus the goal of this study was to examine the
role of oxygen radicals in nicotine-induced impairment of arteriolar reactivity.
We measured diameter of cheek pouch resistance arterioles (approximately 50
micrometer diameter) in response to endothelium-dependent (ACh and ADP) and
independent (nitroglycerin) agonists before and after infusion of vehicle or
nicotine in the absence or presence of superoxide dismutase. ACh, ADP, and
nitroglycerin produced dose-related dilatation of cheek pouch arterioles before
infusion of vehicle or nicotine. Infusion of vehicle, in the absence or presence
of superoxide dismutase (150 U/ml), did not alter endothelium-dependent or
independent arteriolar dilatation. In contrast, infusion of nicotine (2 microgram
. kg-1 . min-1) impaired endothelium-dependent, but not -independent, arteriolar
dilatation. In addition, the effect of nicotine on endothelium-dependent
vasodilatation was reversed by topical application of superoxide dismutase. We
suggest that nicotine impairs endothelium-dependent arteriolar dilatation via an
increase in the synthesis/release of oxygen-derived free radicals.
PMID- 9760320
TI - Important role of carotid afferents in control of breathing.
AB - The purpose of the present study was to determine the effect on breathing in the
awake state of carotid body denervation (CBD) over 1-2 wk after denervation.
Studies were completed on adult goats repeatedly before and 1) for 15 days after
bilateral CBD (n = 8), 2) for 7 days after unilateral CBD (n = 5), and 3) for 15
days after sham CBD (n = 3). Absence of ventilatory stimulation when NaCN was
injected directly into a common carotid artery confirmed CBD. There was a
significant (P < 0.01) hypoventilation during the breathing of room air after
unilateral and bilateral CBD. The maximum PaCO2 increase (8 Torr for unilateral
and 11 Torr for bilateral) occurred approximately 4 days after CBD. This maximum
was transient because by 7 (unilateral) to 15 (bilateral) days after CBD, PaCO2
was only 3-4 Torr above control. CO2 sensitivity was attenuated from control by
60% on day 4 after bilateral CBD and by 35% on day 4 after unilateral CBD. This
attenuation was transient, because CO2 sensitivity returned to control temporally
similar to the return of PaCO2 during the breathing of room air. During mild and
moderate treadmill exercise 1-8 days after bilateral CBD, PaCO2 was unchanged
from its elevated level at rest, but, 10-15 days after CBD, PaCO2 decreased
slightly from rest during exercise. These data indicate that 1) carotid afferents
are an important determinant of rest and exercise breathing and ventilatory CO2
sensitivity, and 2) apparent plasticity within the ventilatory control system
eventually provides compensation for chronic loss of these afferents.
PMID- 9760322
TI - Effects of ovariectomy and hindlimb unloading on skeletal muscle.
AB - Female rats (7-8 mo old, n = 40) were randomly placed into the intact control
(Int) and ovariectomized control (Ovx) groups. Two weeks after ovariectomy,
animals were further divided into intact 2-wk hindlimb unloaded (Int-HU) and
ovariectomized hindlimb unloaded (Ovx-HU). We hypothesized that there would be
greater hindlimb unloading-related atrophy in Ovx than in Int rats. In situ
contractile tests were performed on soleus (Sol), plantaris (Plan), peroneus
longus (Per), and extensor digitorum longus (EDL) muscles. Body weight and Sol
mass were approximately 22% larger in Ovx than in Int group and approximately 18%
smaller in both HU groups than in Int rats (Ovx x HU interaction, P < 0.05), and
there was a similar trend in Plan muscle (P < 0.07). There were main effects (P <
0.05) for both ovariectomy (growth) and hindlimb unloading (atrophy) on
gastrocnemius mass. Mass of the Per and EDL muscles was unaffected by either
ovariectomy or hindlimb unloading. Time to peak twitch tension for EDL and one
half relaxation times for Sol, Plan, Per, and EDL muscles were faster (P < 0.05)
in Ovx than in Int animals. The results suggest that 1) ovariectomy led to
similar increases of approximately 20% in body weight and plantar flexor mass; 2)
hindlimb unloading may have prevented ovariectomy-related muscle growth; 3)
greater atrophy may have occurred in Sol and Plan of Ovx animals compared with
controls; and 4) removal of ovarian hormonal influence decreased skeletal muscle
contraction times.
PMID- 9760321
TI - Effect of simulated microgravity on vascular contractility.
AB - Microgravity was simulated in Sprague-Dawley (SD) and Wistar (W) rats by using a
tail harness to elevate the hindquarters, producing hindlimb unweighting (HU).
After 20 days of HU treatment, blood vessels from both HU and control rats were
cut into 3-mm rings and mounted in tissue baths for the measurement of isometric
contraction. HU treatment decreased the contractile response to 68 mM K+ in
abdominal aorta from W rats. HU treatment also decreased the contraction to 68 mM
K+ in carotid arteries from both rat strains and in femoral arteries from W but
not SD rats. HU treatment reduced the maximal response to norepinephrine in all
arteries except the femoral from SD rats. HU treatment reduced the maximal
response of jugular vein from W rats to 68 mM K+ but had no effect on that
response in femoral vein from either rat strain. HU treatment also had no
significant effect on the maximal response to norepinephrine in veins. These
results demonstrate that HU treatment caused a nearly universal reduction of
contractility in arteries, but generally had no effect in veins.
PMID- 9760323
TI - Influence of acute lung volume change on contractile properties of human
diaphragm.
AB - The effect of stimulus frequency on the in vivo pressure generating capacity of
the human diaphragm is unknown at lung volumes other than functional residual
capacity. The transdiaphragmatic pressure (Pdi) produced by a pair of phrenic
nerve stimuli may be viewed as the sum of the Pdi elicited by the first (T1 Pdi)
and second (T2 Pdi) stimuli. We used bilateral anterior supramaximal magnetic
phrenic nerve stimulation and a digital subtraction technique to obtain the T2
Pdi at interstimulus intervals of 999, 100, 50, 33, and 10 ms in eight normal
subjects at lung volumes between residual volume and total lung capacity. The
reduction in T2 Pdi that we observed as lung volume increased was greatest at
long interstimulus intervals, whereas the T2 Pdi obtained with short
interstimulus intervals remained relatively stable over the 50% of vital capacity
around functional residual capacity. For all interstimulus intervals, the total
pressure produced by the pair decreased as a function of increasing lung volume.
These data demonstrate that, in the human diaphragm, hyperinflation has a
disproportionately severe effect on the summation of pressure responses elicited
by low-frequency stimulations; this effect is distinct from and additional to the
known length-tension relationship.
PMID- 9760324
TI - Effect of sodium in a rehydration beverage when consumed as a fluid or meal.
AB - To investigate the impact of fluid composition on rehydration effectiveness, 30
subjects (15 men and 15 women) were studied during 2 h of rehydration after a
2.5% body weight loss. In a randomized crossover design, subjects rehydrated with
water (H2O), chicken broth (CB: 109.5 mmol/l Na, 25.3 mmol/l K), a carbohydrate
electrolyte drink (CE: 16.0 mmol/l Na, 3.3 mmol/l K), and chicken noodle soup
(Soup: 333.8 mmol/l Na, 13.7 mmol/l K). Subjects ingested 175 ml at the start of
rehydration and 20 min later; H2O was given every 20 min thereafter for a total
volume equal to body weight loss during dehydration. At the end of the
rehydration period, plasma volume was not significantly different from
predehydration values in the CB (-1.6 +/- 1.1%) and Soup (-1.4 +/- 0.9%) trials.
In contrast, plasma volume remained significantly (P < 0.01) below predehydration
values in the H2O (-5.6 +/- 1.1%) and CE (-4.2 +/- 1.0%) trials after the
rehydration period. Urine volume was greater in the CE (310 +/- 30 ml) than in
the CB (188 +/- 20 ml) trial. Urine osmolality was higher in the CB and Soup
trials than in the CE trial. Urinary sodium concentration was higher in the Soup
and CB trials than in the CE and H2O trials. These results provide evidence that
the inclusion of sodium in rehydration beverages, as well as consumption of a
sodium-containing liquid meal, increases fluid retention and improves plasma
volume restoration.
PMID- 9760325
TI - Fiber type and citrate synthase activity in the human gastrocnemius and vastus
lateralis with aging.
AB - The purpose of this study was to determine whether enzymatic and histochemical
characteristics of human skeletal muscle are altered with aging. Tissues from the
vastus lateralis (VL) and gastrocnemius were analyzed for citrate synthase (CS)
activity and fiber type in 55 sedentary men (age range 18-80 yr). In this
population, CS activity in the gastrocnemius was negatively related to age (r =
0. 32, P < 0.05); there was no relationship in the VL. Treadmill-determined
maximal oxygen consumption was positively related (r = 0.40, P < 0.05) to CS in
the gastrocnemius but not in the VL. CS activity in the gastrocnemius was 24%
lower in the oldest (>/=60 yr, n = 10) vs. the youngest (=30 yr; n = 12) men;
there was no change in CS activity in the VL with aging. No changes in fiber type
were evident with age in either muscle. These data suggest a reduction in
oxidative enzyme activity in human skeletal muscle with the aging process; this
relationship may be muscle-group specific.
PMID- 9760326
TI - Endurance in high-fat-fed rats: effects of carbohydrate content and fatty acid
profile.
AB - The purpose of this experiment was to study endurance performance and substrate
storage and utilization in fat- or carbohydrate-fed rats. Ninety-nine rats were
randomly divided into three groups and over 4 wk were fed either a carbohydrate
rich [CHO; 10% total energy content in the diet (E%) fat, 20 E% protein, 70 E%
carbohydrate] diet or one of two fat-rich diets (65 E% fat, 20 E% protein, 15 E%
carbohydrate) containing either saturated (Sat) or monounsaturated fatty acids
(Mono). Each dietary group was randomly assigned to a trained (6 days/wk,
progressive to 60 min, 28 m/min at a 10% incline) or a sedentary group. Rats were
killed either before or after a treadmill endurance run to exhaustion. Training
increased endurance (206%), but diet composition did not affect endurance in
either trained or sedentary rats. beta-Hydroxyacyl-CoA dehydrogenase activity was
increased in fat-fed but not carbohydrate-fed rats (P < 0.05). Respiratory
exchange ratio during the initial phase of exercise was lower after the Mono
compared with the Sat diet (P < 0. 05) and higher after the CHO than the Sat diet
(P < 0.05). Thus adaptation to a high-fat diet containing a moderate amount of
carbohydrates did not induce enhanced endurance in either trained or untrained
rats; however, substrate utilization was modulated by both amount and type of
dietary fat during the initial stage of exercise in trained and sedentary rats.
PMID- 9760327
TI - Creatine supplementation and age influence muscle metabolism during exercise.
AB - Young [n = 5, 30 +/- 5 (SD) yr] and middle-aged (n = 4, 58 +/- 4 yr) men and
women performed single-leg knee-extension exercise inside a whole body magnetic
resonance system. Two trials were performed 7 days apart and consisted of two 2
min bouts and a third bout continued to exhaustion, all separated by 3 min of
recovery. 31P spectra were used to determine pH and relative concentrations of
Pi, phosphocreatine (PCr), and beta-ATP every 10 s. The subjects consumed 0.3 g .
kg-1 . day-1 of a placebo (trial 1) or creatine (trial 2) for 5 days before each
trial. During the placebo trial, the middle-aged group had a lower resting PCr
compared with the young group (35.0 +/- 5.2 vs. 39.5 +/- 5.1 mmol/kg, P < 0.05)
and a lower mean initial PCr resynthesis rate (18.1 +/- 3.5 vs. 23.2 +/- 6.0 mmol
. kg-1 . min-1, P < 0.05). After creatine supplementation, resting PCr increased
15% (P < 0.05) in the young group and 30% (P < 0.05) in the middle-aged group to
45.7 +/- 7.5 vs. 45.7 +/- 5.5 mmol/kg, respectively. Mean initial PCr resynthesis
rate also increased in the middle-aged group (P < 0.05) to a level not different
from the young group (24.3 +/- 3.8 vs. 24.2 +/- 3.2 mmol . kg-1 . min-1). Time to
exhaustion was increased in both groups combined after creatine supplementation
(118 +/- 34 vs. 154 +/- 70 s, P < 0.05). In conclusion, creatine supplementation
has a greater effect on PCr availability and resynthesis rate in middle-aged
compared with younger persons.
PMID- 9760328
TI - Moderate exercise increases postexercise thresholds for vasoconstriction and
shivering.
AB - The purpose of this study was to evaluate the effect of exercise on the
subsequent postexercise thresholds for vasoconstriction and shivering. On two
separate days, with six subjects (3 women), a whole body water-perfused suit
slowly decreased mean skin temperature (approximately 7.0 degreesC/h) until
thresholds for vasoconstriction and shivering were clearly established. Subjects
were then rewarmed by increasing water temperature until both esophageal and mean
skin temperatures returned to near-baseline values. Subjects either performed 15
min of cycle ergometry (65% maximal O2 consumption) followed by 30 min of
recovery (Exercise) or remained seated with no exercise for 45 min (Control).
Subjects were then cooled again. We mathematically compensated for changes in
skin temperatures by using the established linear cutaneous contribution of skin
to the control of vasoconstriction and shivering (20%). The calculated core
temperature threshold (at a designated skin temperature of 30.0 degreesC) for
vasoconstriction increased significantly from 36.64 +/- 0.20 to 36.89 +/- 0.22
degreesC postexercise (P < 0.01). Similarly, the shivering threshold increased
from 35.73 +/- 0.13 to 36.13 +/- 0.12 degreesC postexercise (P < 0.01). In
contrast, sequential measurements, without exercise, demonstrate a time-dependent
decrease in both the vasoconstriction (0.10 degreesC) and shivering (0.12
degreesC) thresholds. These data indicate that exercise has a prolonged effect by
increasing the postexercise thresholds for both cold thermoregulatory responses.
PMID- 9760329
TI - Endothelial modulation of neural sympathetic vascular tone in canine skeletal
muscle.
AB - The effect of nitric oxide synthase (NOS) inhibition and endothelin-A (ETA)
receptor blockade on neural sympathetic control of vascular tone in the
gastrocnemius muscle was examined in anesthetized dogs under conditions of
constant flow. Muscle perfusion pressure (MPP) was measured before and after NOS
inhibition (Nomega-nitro-L-arginine methyl ester; L-NAME) and ETA-receptor
blockade [cyclo-(D-Trp-d-Asp-Pro-D-Val-Leu); BQ-123]. Zero and maximum
sympathetic nerve activities were achieved by sciatic nerve cold block and
stimulation, respectively. In group 1 (n = 6), MPP was measured 1) before nerve
cold block, 2) during nerve cold block, and 3) during nerve stimulation.
Measurements under these conditions were repeated after L-NAME and then BQ-123.
The same protocol was followed in group 2 (n = 6) except that the order of L-NAME
and BQ-123 was reversed. MPP and muscle vascular resistance (MVR) increased after
L-NAME and then decreased to control values after BQ-123. MVR decreased after BQ
123 alone and, with the addition of L-NAME, increased to a level not different
from that observed during the control period. MVR fell during nerve cold block.
This response was not affected by administration of L-NAME followed by BQ-123,
but it was attenuated by administration of BQ-123 before L-NAME. The constrictor
response during sympathetic nerve stimulation was enhanced by L-NAME; no further
effect was observed with BQ-123, nor was the response affected when BQ-123 was
given first. These findings indicate that endothelin contributes to 1) basal
vascular tone in skeletal muscle and 2) the increase in skeletal muscle vascular
resistance after NOS inhibition. Finally, nitric oxide "buffers" the degree of
constriction in skeletal muscle vasculature during maximal sympathetic
stimulation.
PMID- 9760330
TI - Effect of endurance training on cardiac morphology in Alaskan sled dogs.
AB - The cardiac morphology of 77 conscious Alaskan sled dogs before and after 5 mo of
endurance training (20 km/day team pulling a sled and musher) was studied using
two-dimensional and M-mode echocardiography. Subgroups included dogs with at
least one season of previous training ("veterans") and dogs undergoing their
first season of training ("rookies"). Training resulted in a significant (P <
0.05) decrease in resting heart rate (-15%) and significant increases in
interventricular septal thickness (systole, 15%; diastole, 13%), left ventricular
(LV) internal dimension in diastole (LVIDd, 4%), LV free wall thickness in
systole (9%) and diastole (LVWd, 9%), and left atrial diameter (5%) in all dogs,
but the increase in LVWd was greater in rookies (16%) than in veterans (7%).
Training increased end-diastolic volume index (8%), LV mass index (24%), and
heart weight index (24%) and decreased the LVIDd-to-LVWd ratio (-6%) but did not
alter cardiac index. We conclude that increased LV mass attributable to LV
dilation and hypertrophy is associated with endurance training in Alaskan sled
dogs. Disproportionate LV wall thickening accompanying LV dilation suggests that
cardiac morphological changes are due to volume and pressure loading. These
training-induced changes are similar to those documented in human athletes
undergoing combined isometric and isotonic training and differ from studies of
dogs trained on treadmills.
PMID- 9760331
TI - Scaling of submaximal oxygen uptake with body mass and combined mass during
uphill treadmill bicycling.
AB - This study examined the scaling relationships of net O2 uptake [V(O2)(net) =
V(O2) - resting V(O2)] to body mass (MB) and combined mass (MC = MB + bicycle)
during uphill treadmill bicycling. It was hypothesized that V(O2)(net) (l/min)
would scale proportionally with MC [i.e., VO2(net) approximately M1.0C] and less
than proportionally with MB [i.e., V(O2)(net) approximately MB]. Twenty-five
competitive cyclists [73.9 +/- 8.8 and 85.0 +/- 9.0 (SD) kg for MB and MC,
respectively] rode their bicycles on a treadmill at 3.46 m/s and grades of 1.7,
3.5, 5.2, and 7.0% while V(O2) was measured. Multiple log-linear regression
procedures were applied to the pooled V(O2)(net) data to determine the exponents
for MC and MB after statistically controlling for differences in treadmill grade
and dynamic friction. The regression models were highly significant (R2 = 0.95, P
< 0.001). Exponents for MC (0.99, 95% confidence interval = 0.80-1.18) and MB
(0.89, 95% confidence interval = 0.72-1. 07) did not differ significantly from
each other or 1.0. It was concluded that the 0.99 MC exponent was due to
gravitational resistance, whereas the MB exponent was <1.0 because the bicycles
were relatively lighter for heavier cyclists.
PMID- 9760332
TI - O2 uptake kinetics after acetazolamide administration during moderate- and heavy
intensity exercise.
AB - Inhibition of carbonic anhydrase (CA) is associated with a lower plasma lactate
concentration ([La-]pl) during fatiguing exercise. We hypothesized that a lower
[La-]pl may be associated with faster O2 uptake (V(O2)) kinetics during constant
load exercise. Seven men performed cycle ergometer exercise during control (Con)
and acute CA inhibition with acetazolamide (Acz, 10 mg/kg body wt iv). On 6
separate days, each subject performed 6-min step transitions in work rate from 0
to 100 W (below ventilatory threshold, VE(T). Gas exchange was measured breath by breath. Trials were interpolated at
1-s intervals and ensemble averaged to yield a single response. The mean response
time (MRT, i.e., time to 63% of total exponential increase) for on- and off
transients was determined using a two- (VE(T)). Arterialized venous blood was sampled from a dorsal hand vein and
analyzed for [La-]pl. MRT was similar during Con (31.2 +/- 2.6 and 32.7 +/- 1.2 s
for on and off, respectively) and Acz (30.9 +/- 3.0 and 31.4 +/- 1.5 s for on and
off, respectively) for work rates VE(T), MRT was similar
between Con (69.1 +/- 6.1 and 50.4 +/- 3.5 s for on and off, respectively) and
Acz (69.7 +/- 5.9 and 53.8 +/- 3.8 s for on and off, respectively). On- and off
MRTs were slower for >VE(T) than for VE(T) exercise but was lower at the end of the
transition during Acz (1.4 +/- 0.2 and 7.1 +/- 0.5 mmol/l for VE(T)
respectively) than during Con (2.0 +/- 0.2 and 9.8 +/- 0.9 mmol/l for VE(T), respectively). CA inhibition does not affect O2 utilization at the onset
of VE(T) exercise, suggesting that the contribution of oxidative
phosphorylation to the energy demand is not affected by acute CA inhibition with
Acz.
PMID- 9760333
TI - Faster adjustment of O2 delivery does not affect V(O2) on-kinetics in isolated in
situ canine muscle.
AB - The mechanism(s) limiting muscle O2 uptake (VO2) kinetics was investigated in
isolated canine gastrocnemius muscles (n = 7) during transitions from rest to 3
min of electrically stimulated isometric tetanic contractions (200-ms trains, 50
Hz; 1 contraction/2 s; 60-70% of peak V(O2)). Two conditions were mainly
compared: 1) spontaneous adjustment of blood flow (Q) [control, spontaneous Q (C
Spont)]; and 2) pump-perfused Q, adjusted approximately 15 s before contractions
at a constant level corresponding to the steady-state value during contractions
in C Spont [faster adjustment of O2 delivery (Fast O2 Delivery)]. During Fast O2
Delivery, 1-2 ml/min of 10(-2) M adenosine were infused intra-arterially to
prevent inordinate pressure increases with the elevated Q. The purpose of the
study was to determine whether a faster adjustment of O2 delivery would affect
V(O2) kinetics. Q was measured continuously; arterial (Ca(O2)) and popliteal
venous (Cv(O2)) O2 contents were determined at rest and at 5- to 7-s intervals
during contractions; O2 delivery was calculated as Q x Ca(O2), and V(O2) was
calculated as Q x arteriovenous O2 content difference. Times to reach 63% of the
difference between baseline and steady-state VO2 during contractions were 23.8 +/
2.0 (SE) s in C Spont and 21.8 +/- 0.9 s in Fast O2 Delivery (not significant).
In the present experimental model, elimination of any delay in O2 delivery during
the rest-to-contraction transition did not affect muscle V(O2) kinetics, which
suggests that this kinetics was mainly set by an intrinsic inertia of oxidative
metabolism.
PMID- 9760334
TI - Peripheral O2 diffusion does not affect V(O2)on-kinetics in isolated insitu
canine muscle.
AB - To test the hypothesis that muscle O2 uptake (V(O2)) on-kinetics is limited, at
least in part, by peripheral O2 diffusion, we determined the V(O2) on-kinetics in
1) normoxia (Control); 2) hyperoxic gas breathing (Hyperoxia); and 3) hyperoxia
and the administration of a drug (RSR-13, Allos Therapeutics), which right-shifts
the Hb-O2 dissociation curve (Hyperoxia+RSR-13). The study was conducted in
isolated canine gastrocnemius muscles (n = 5) during transitions from rest to 3
min of electrically stimulated isometric tetanic contractions (200-ms trains, 50
Hz; 1 contraction/2 s; 60-70% peak V(O2)). In all conditions, before and during
contractions, muscle was pump perfused with constantly elevated blood flow (Q),
at a level measured at steady state during contractions in preliminary trials
with spontaneous Q x Adenosine was infused intra-arterially to prevent inordinate
pressure increases with the elevated Q x Q was measured continuously, arterial
and popliteal venous O2 concentrations were determined at rest and at 5- to 7-s
intervals during contractions, and V(O2) was calculated as Q x arteriovenous O2
content difference. PO2 at 50% HbO2 saturation (P50) was calculated. Mean
capillary PO2 (Pc(O2)) was estimated by numerical integration. P50 was higher in
Hyperoxia+RSR-13 [40 +/- 1 (SE) Torr] than in Control and in Hyperoxia (31 +/- 1
Torr). After 15 s of contractions, Pc(O2) was higher in Hyperoxia (97 +/- 9 Torr)
vs. Control (53 +/- 3 Torr) and in Hyperoxia+RSR-13 (197 +/- 39 Torr) vs.
Hyperoxia. The time to reach 63% of the difference between baseline and steady
state V(O2) during contractions was 24.7 +/- 2.7 s in Control, 26.3 +/- 0.8 s in
Hyperoxia, and 24.7 +/- 1.1 s in Hyperoxia+RSR-13 (not significant). Enhancement
of peripheral O2 diffusion (obtained by increased PcO2 at constant O2 delivery)
during the rest-to-contraction (60-70% of peak V(O2)) transition did not affect
muscle V(O2) on- kinetics.
PMID- 9760335
TI - Chemo- and baroresponses differ in African-Americans and Caucasians in sleep.
AB - To determine sleep effects on baro- and ventilatory responses to transient chemo-
and barostimulation in African-Americans and Caucasians, 26 nonobese normotensive
young subjects (13 African-Americans and 13 Caucasians) were studied awake and in
non-rapid-eye movement (NREM) and rapid-eye-movement sleep during induced
transient hypoxemia (N2), hypertension (phenylephrine, PE), and concomitant
hypoxemia and hypertension (N2 + PE). Arterial blood pressure was recorded by
plethysmographic volume clamp, minute ventilation by pneumotachograph, and
arterial O2 saturation by pulse oximeter. For all subjects, chronotropic
baroresponse (Deltapulse interval/Deltasystolic blood pressure, where Delta is
change) increased with NREM sleep (P = 0.007). Baroresponse slope was greater in
Caucasians than in African-Americans (ANOVA, P = 0.02). Hypoxemic ventilatory
response (Deltaminute ventilation/Deltaarterial O2 saturation) was greater in
African-Americans than in Caucasians in NREM sleep (P = 0.01), as was hypoxemic
attenuation of baroresponse (N2 + PE, P = 0.03). These data suggest sleep-related
differences in arterial chemo- and baroreceptor responses in normal young African
Americans and Caucasians, which may have implications concerning development of
systemic hypertension.
PMID- 9760336
TI - Effect of urokinase on disseminated intravascular coagulation.
AB - Our study evaluated the possible therapeutic effect of urokinase in treating the
microthrombiotic effects of disseminated intravascular coagulation by assisting
the activation of endogenous plasminogen. Twenty-six pigs were anesthetized,
intubated, mechanically ventilated, and surgically catheterized. Septic shock was
induced in all 26 pigs by an intravenous infusion of heat-killed Escherichia
coli. The pigs were divided into two sets of experiments: in experiment 2 (n =
14), one-half received an intravenous dose of urokinase 1 h after heat-killed E.
coli infusion and in experiment 3 (n = 12) one-half received an intravenous bolus
dose and a continuous drip of urokinase 2 h after heat-killed E. coli infusion.
The untreated pigs served as controls. Hemodynamic parameters, blood chemistries,
and blood gases were analyzed. Urokinase given 1 h after bacterial toxin infusion
significantly restored blood flow, resulting in an increase in cardiovascular and
pulmonary function and improved survival rate (43% control vs. 100% treated, 24-h
experimental period). Treatment given after 2 h showed some significant effect on
pulmonary function; however, within 10 h of E. coli infusion, mortality rates in
control and treated groups were 100 and 83%, respectively. Early administration
of urokinase after onset of disseminated intravascular coagulation restored blood
flow and helped resolve organ damage.
PMID- 9760337
TI - Spaceflight and development of immune responses.
AB - The NIH.R1 Space Shuttle experiment was designed to study the effects of
spaceflight on rodent development. Pregnant rats were flown on the Space Shuttle
for 11 days, and pregnant control rats were maintained in animal enclosure
modules in a ground-based chamber under conditions approximating those in flight.
Additional controls were in standard housing. The effects of the flight on
immunological parameters of dams, fetuses, and pups were determined.
Blastogenesis of spleen cells in response to mitogen was inhibited in flown dams
but was not inhibited in cells from their pups. Interferon-gamma production by
spleen cells showed a trend toward inhibition in flown dams but not in their
pups. The response of bone marrow cells to colony-stimulating factor showed a
trend toward inhibition after spaceflight in dams, but the response of fetus and
pup liver cells was not inhibited. Total serum IgG was not affected by
spaceflight. None of the examined immune parameters that were altered in rat dams
after spaceflight was found to be altered in their offspring.
PMID- 9760338
TI - Within-night variation in respiratory effort preceding apnea termination and EEG
delta power in sleep apnea.
AB - We studied the within-night variability of the maximum esophageal pressure
deflection before apnea termination (DPmax) in nine patients with severe
obstructive sleep apnea as an index of the arousal threshold and the mean
electroencephalogram (EEG) delta power for each 30 s as an index of the timing of
sleep cycles. Periodicity in the time variation of delta power and DPmax was
analyzed by determining their power spectral density and their relationship
determined by cross correlation. DPmax and delta power varied cyclically and in
phase with a major periodicity (major peak in power spectral density) of 117.6 +/
8.8 (SE) min. The correlation between the values of DPmax and delta power was
significant (P < 0.001) in each subject (mean r = 0.47 +/- 0.03), and the
coherence between DPmax and delta power at their dominant frequency was high.
Within cycles of non-rapid-eye-movement sleep, DPmax and delta power increased,
reaching peak values on average at or after midcycle. These findings suggest that
the arousal threshold to airway occlusion in patients with obstructive sleep
apnea varies cyclically during the night synchronous to the underlying cycles of
sleep.
PMID- 9760339
TI - Exercise-training-induced alterations in hepatic function in mares.
AB - The effects of exercise training on hepatic function in horses were determined by
studying the plasma clearance of antipyrine (20 mg/kg iv) in adult mares that
either underwent treadmill training for 5 wk (n = 7) or remained in box stalls
for the same time period (n = 6). Training consisted of treadmill exercise at 60%
(12 min/day) and 90% (3 min/day) of pretraining maximal oxygen consumption
(V(O2)max) for 6 days/wk for 5 wk. V(O2)max and velocity to obtain a blood
lactate concentration of 4 mmol/l were significantly increased (from 129 to 149
ml x min-1 x kg-1 and from 5.6 to 6.1 m/s, respectively) as a result of training.
The plasma clearance and volume of distribution of antipyrine increased
significantly in the trained group (from 5.5 to 6.4 ml x min-1 x kg-1 and from
813 to 881 ml/kg, respectively) and decreased significantly in the untrained
group. Elimination half-lives did not change as a result of training or box rest.
Increases in plasma antipyrine clearance were indicative of an increase in
hepatic metabolism of antipyrine. Increases in the volume of distribution of
antipyrine suggest that total body water increases as a result of exercise
training.
PMID- 9760340
TI - Individual variation in response to altitude training.
AB - Moderate-altitude living (2,500 m), combined with low-altitude training (1,250 m)
(i.e., live high-train low), results in a significantly greater improvement in
maximal O2 uptake (V(02)max) and performance over equivalent sea-level training.
Although the mean improvement in group response with this "high-low" training
model is clear, the individual response displays a wide variability. To determine
the factors that contribute to this variability, 39 collegiate runners (27 men,
12 women) were retrospectively divided into responders (n = 17) and nonresponders
(n = 15) to altitude training on the basis of the change in sea-level 5,000-m run
time determined before and after 28 days of living at moderate altitude and
training at either low or moderate altitude. In addition, 22 elite runners were
examined prospectively to confirm the significance of these factors in a separate
population. In the retrospective analysis, responders displayed a significantly
larger increase in erythropoietin (Epo) concentration after 30 h at altitude
compared with nonresponders. After 14 days at altitude, Epo was still elevated in
responders but was not significantly different from sea-level values in
nonresponders. The Epo response led to a significant increase in total red cell
volume and V(O2) max in responders; in contrast, nonresponders did not show a
difference in total red cell volume or V(O2)max after altitude training.
Nonresponders demonstrated a significant slowing of interval-training velocity at
altitude and thus achieved a smaller O2 consumption during those intervals,
compared with responders. The acute increases in Epo and V(O2)max were
significantly higher in the prospective cohort of responders, compared with
nonresponders, to altitude training. In conclusion, after a 28-day altitude
training camp, a significant improvement in 5,000-m run performance is, in part,
dependent on 1) living at a high enough altitude to achieve a large acute
increase in Epo, sufficient to increase the total red cell volume and V(O2)max,
and 2) training at a low enough altitude to maintain interval training velocity
and O2 flux near sea-level values.
PMID- 9760341
TI - Phosphocreatine hydrolysis during submaximal exercise: the effect of FIO2.
AB - There is evidence that the concentration of the high-energy phosphate metabolites
may be altered during steady-state submaximal exercise by the breathing of
different fractions of inspired O2 (FIO2). Whereas it has been suggested that
these changes may be the result of differences in time taken to achieve steady
state O2 uptake (V(O2)) at different FIO2 values, we postulated that they are due
to a direct effect of O2 tension. We used 31P-magnetic resonance spectroscopy
during constant-load, steady-state submaximal exercise to determine 1) whether
changes in high-energy phosphates do occur at the same V(O2) with varied FIO2 and
2) that these changes are not due to differences in V(O2) onset kinetics. Six
male subjects performed steady-state submaximal plantar flexion exercise [7.2 +/-
0.6 (SE) W] for 10 min while lying supine in a 1.5-T clinical scanner. Magnetic
resonance spectroscopy data were collected continuously for 2 min before
exercise, 10 min during exercise, and 6 min during recovery. Subjects performed
three different exercise bouts at constant load with the FIO2 switched after 5
min of the 10-min exercise bout. The three exercise treatments were 1) FIO2 of
0.1 switched to 0.21, 2) FIO2 of 0.1 switched to 1.00, and 3) FIO2 of 1.00
switched to 0.1. For all three treatments, the FIO2 switch significantly (P =
0.05) altered phosphocreatine: 1) 55.5 +/- 4.8 to 67.8 +/- 4.9% (%rest); 2) 59.0
+/- 4.3 to 72.3 +/- 5.1%; and 3) 72.6 +/- 3.1 to 64.2 +/- 3.4%, respectively.
There were no significant differences in intracellular pH for the three
treatments. The results demonstrate that the differences in phosphocreatine
concentration with varied FIO2 are not the result of different V(O2) onset
kinetics, as this was eliminated by the experimental design. These data also
demonstrate that changes in intracellular oxygenation, at the same work
intensity, result in significant changes in cell homeostasis and thereby suggest
a role for metabolic control by O2 even during submaximal exercise.
PMID- 9760342
TI - Effect of time-varying load on degree of bronchoconstriction in the dog.
AB - It is well established that the degree of airway smooth muscle shortening
produced by a given dose of bronchial agonist is greatly affected by lung volume.
The airways are tethered by parenchymal attachments, the tension of which
increases progressively with lung volume, thereby presenting a commensurately
increasing hindrance to smooth muscle contraction. Earlier studies (P. F. Dillon,
M. O. Aksoy, S. P. Driska, and R. A. Murphy. Science 211: 495-497, 1981)
presented evidence that smooth muscle contraction initially involves rapidly
cycling cross bridges, which then change to noncycling (latch) bridges. They also
suggested that most of the muscle shortening occurs during the early rapid cross
bridge phase. This implies that smooth muscle subject to a given load early in
contraction should shorten less than when it is subject to the same load later
on. An in vitro study (W. Li and N. L. Stephens. Can. J. Physiol. Pharmacol. 72:
1458-1463, 1994) obtained support for this notion. To test this hypothesis in
vivo, we measured the changes in lung impedance at 1 and 6 Hz produced in dogs by
a bolus intravenous injection of methacholine when lung volume was increased for
10 s at different times after injection. We found that the changes in mechanics
were greatly inhibited, whereas lung volume was elevated. However, when lung
volume was returned to its initial level, the lung mechanics continued to change
at a rate unaffected by the preceding volume change. We conclude that temporary
mechanical inhibition of airway smooth muscle shortening in the normal dog in
vivo merely delays an otherwise normal course of contraction.
PMID- 9760344
TI - Magnitude and time course of hemodynamic responses to Mueller maneuvers in
patients with congestive heart failure.
AB - To simulate the immediate hemodynamic effect of negative intrathoracic pressure
during obstructive apneas in congestive heart failure (CHF), without inducing
confounding factors such as hypoxia and arousals from sleep, eight awake patients
performed, at random, 15-s Mueller maneuvers (MM) at target intrathoracic
pressures of -20 (MM -20) and -40 cmH2O (MM -40), confirmed by esophageal
pressure, and 15-s breath holds, as apneic time controls. Compared with quiet
breathing, at baseline, before these interventions, the immediate effects [first
5 cardiac cycles (SD), P values refer to MM -40 compared with breath holds] of
apnea, MM -20, and MM -40 were, for left ventricular (LV) systolic transmural
pressure (Ptm), 1.0 +/- 1. 9, 7.2 +/- 3.5, and 11.3 +/- 6.8 mmHg (P < 0.01); for
systolic blood pressure (SBP), 2.9 +/- 2.6, -5.5 +/- 3.4, and -12.1 +/- 6.8 mmHg
(P < 0.01); and for stroke volume (SV) index, 0.4 +/- 2.8, -4.1 +/- 2.8, and -6.9
+/- 2.3 ml/m2 (P < 0.001), respectively. Corresponding values over the last five
cardiac cycles were for LVPtm 6.4 +/- 4.4, 5.4 +/- 6.6, and -4.5 +/- 9.1 mmHg (P
< 0.01); for SBP 6.9 +/- 4.2, -8.2 +/- 7.7, and -24.2 +/- 6.9 mmHg (P < 0.01);
and for SV index -0. 4 +/- 2.1, -5.2 +/- 2.8, and -9.2 +/- 4.8 ml/m2 (P < 0.001),
respectively. Thus, in CHF patients, the initial hemodynamic response to the
generation of negative intrathoracic pressure includes an immediate increase in
LV afterload and an abrupt fall in SV. The magnitude of response is proportional
to the intensity of the MM stimulus. By the end of a 15-s MM -40, LVPtm falls
below baseline values, yet SV and SBP do not recover. Thus, when -40 cmH2O
intrathoracic pressure is sustained, additional mechanisms, such as a drop in LV
preload due to ventricular interaction, are engaged, further reducing SV. The net
effect of MM -40 was a 33% reduction in SV index (from 27 to 18 ml/min2), and a
21% reduction in SBP (from 121 to 96 mmHg). Obstructive apneas can have adverse
effects on systemic and, possibly, coronary perfusion in CHF through dynamic
mechanisms that are both stimulus and time dependent.
PMID- 9760343
TI - Leg mass and lower body negative pressure tolerance in men and women.
AB - To explore the hypothesis that lower body muscle mass correlates with orthostatic
tolerance, 18 healthy volunteers (age 18-48 yr; 10 men, 8 women) underwent a
graded lower body negative pressure (LBNP) protocol consisting of six, 5-min
stages of suction up to 60 mmHg in 10-mmHg increments. Forearm blood flow, heart
rate, and blood pressure were measured, and forearm vascular resistance was
calculated. Leg muscle mass was assessed by dual-energy X-ray absorptiometry. All
subjects received standard intravenous hydration for at least 8 h before the
study. Six men and four women completed all stages of LBNP. Four men and four
women developed presyncopal symptoms, including marked bradycardia and/or
hypotension, at LBNP levels of 30 mmHg (n = 2;1 man, 1 woman), 40 mmHg (n = 2;1
man, 1 woman), and 50 mmHg (n = 4;2 men, 2 women). The presyncopal subjects had
leg muscle masses ranging from 19.5 to 25.2 kg in men and from 11.7 to 16.6 kg in
women. In subjects who completed all stages of LBNP, leg muscle mass ranged from
17.5 to 24.1 kg in men and from 10.4 to 18.0 kg in women. Leg muscle mass did not
differ between presyncopal subjects and those who completed the protocol.
Furthermore, there were no differences in the hemodynamic responses to LBNP
between subjects with low vs. high leg mass. These data suggest that leg muscle
mass is not a critical determinant of LBNP tolerance in otherwise healthy men and
women.
PMID- 9760345
TI - Stimulation of breathing by activation of pulmonary peripheral afferents in
rabbits.
AB - Respiratory response to selective activation of vagal afferents in the peripheral
airways was investigated in anesthetized, open-chest, and artificially ventilated
rabbits. Phrenic activity was used as an index of central respiratory drive
before and after injection of hypertonic saline (8.1%, 0.1 ml) into the periphery
of the lung to stimulate the afferents. The amplitude of "integrated" phrenic
activity and phrenic burst rate increased by 19 +/- 3.4 and 53.7 +/- 12.7% (n =
23; P < 0.001), respectively. The response peaked at 5.5 +/- 1.6 s and returned
to the baseline at 7 min (median) after the injection. The magnitude of the
response was positively related to the concentration of injected NaCl. The
response could not be elicited by injection of normal saline and was abolished by
vagotomy. Because artificial ventilation caused phrenic activity to be entrained
with the ventilator, respiratory drive was further assessed after the ventilator
was stopped. Again, neural hyperpnea and tachypnea were observed. Because
activation of a small fraction of the pulmonary peripheral afferents resulted in
vigorous stimulation of respiratory drive, we speculate that initiation of this
reflex may contribute to hyperpnea and tachypnea under both physiological and
pathophysiological conditions.
PMID- 9760346
TI - Effect of caffeine on metabolism, exercise endurance, and catecholamine responses
after withdrawal.
AB - In this study the effects of acute caffeine ingestion on exercise performance,
hormonal (epinephrine, norepinephrine, insulin), and metabolic (free fatty acids,
glycerol, glucose, lactate, expired gases) parameters during short-term
withdrawal from dietary caffeine were investigated. Recreational athletes who
were habitual caffeine users (n = 6) (maximum oxygen uptake 54.5 +/- 3.3 ml x kg
1 x min-1 and daily caffeine intake 761.3 +/- 11.8 mg/day) were tested under
conditions of no withdrawal and 2-day and 4-day withdrawal from dietary caffeine.
There were seven trials in total with a minimum of 10 days between trials. On the
day of the exercise trial, subjects ingested either dextrose placebo or 6 mg/kg
caffeine in capsule form 1 h before cycle ergometry to exhaustion at 80-85% of
maximum oxygen uptake. Test substances were assigned in a random, double-blind
manner. A final placebo control trial completed the experiment. There was no
significant difference in any measured parameters among days of withdrawal after
ingestion of placebo. At exhaustion in the 2- and 4-day withdrawal trials, there
were significant increases in plasma norepinephrine in response to caffeine
ingestion. Caffeine-induced increases in serum free fatty acids occurred after 4
days and only at rest. Subjects responded to caffeine with increases in plasma
epinephrine (P < 0.05) at exhaustion and prolonged exercise time in all caffeine
trials compared with placebo, regardless of withdrawal from caffeine. It is
concluded that increased endurance is unrelated to hormonal or metabolic changes
and that it is not related to prior caffeine habituation in recreational
athletes.
PMID- 9760347
TI - Caffeine, performance, and metabolism during repeated Wingate exercise tests.
AB - Investigations examining the ergogenic and metabolic influence of caffeine during
short-term high-intensity exercise are few in number and have produced
inconsistent results. This study examined the effects of caffeine on repeated
bouts of high-intensity exercise in recreationally active men. Subjects (n = 9)
completed four 30-s Wingate (WG) sprints with 4 min of rest between each exercise
bout on two separate occasions. One hour before exercise, either placebo (P1;
dextrose) or caffeine (Caf; 6 mg/kg) capsules were ingested. Caf ingestion did
not have any effect on power output (peak or average) in the first two WG tests
and had a negative effect in the latter two exercise bouts. Plasma epinephrine
concentration was significantly increased 60 min after Caf ingestion compared
with P1; however, this treatment effect disappeared once exercise began. Caf
ingestion had no significant effect on blood lactate, O2 consumption, or aerobic
contribution at any time during the protocol. After the second Wingate test,
plasma NH3 concentration increased significantly from the previous WG test and
was significantly higher in the Caf trial compared with P1. These data
demonstrate no ergogenic effect of caffeine on power output during repeated bouts
of short-term, intense exercise. Furthermore, there was no indication of
increased anaerobic metabolism after Caf ingestion with the exception of an
increase in NH3 concentration.
PMID- 9760348
TI - Ozone enhances excitabilities of pulmonary C fibers to chemical and mechanical
stimuli in anesthetized rats.
AB - Acute exposure to ozone (O3) enhances pulmonary chemoreflex response to
capsaicin, and an increased sensitivity of bronchopulmonary C-fiber afferent
endings may be involved. The present study was aimed at determining the effect of
O3 on the responses of pulmonary C fibers to chemical and mechanical stimuli. A
total of 31 C fibers were studied in anesthetized, open-chest, and vagotomized
rats. During control, right atrial injection of a low dose of capsaicin abruptly
evoked a short and mild burst of discharge [0.77 +/- 0.28 impulses (imp)/s, 2-s
average]. After acute exposure to O3 (3 parts/million for 30 min), there was no
significant change in arterial blood pressure, tracheal pressure, or baseline
activity of C fibers. However, the stimulatory effect of the same dose of
capsaicin on these fibers was markedly enhanced (6.05 +/- 0.88 impulses/s; P <
0.01) and prolonged immediately after O3 exposure, and returned toward control in
54 +/- 6 min. Similarly, the pulmonary C-fiber response to injection of a low
dose of lactic acid was also elevated after O3 exposure. Furthermore, O3 exposure
significantly potentiated the C-fiber response to constant-pressure (tracheal
pressure = 30 cmH2O) lung inflation (control: 0.19 +/- 0.07 imp/s; after O3: 1.12
+/- 0.26 imp/s; P < 0.01). In summary, these results show that the excitabilities
of pulmonary C-fiber afferents to lung inflation and injections of chemical
stimulants are markedly potentiated after acute exposure to O3, suggesting a
possible involvement of these afferents in the O3-induced changes in breathing
pattern and chest discomfort in humans.
PMID- 9760349
TI - Effect of exercise timing on postprandial lipemia and HDL cholesterol
subfractions.
AB - The purpose of the study was to examine the effect of exercise timing on
postprandial lipemia responses. Subjects were 21 recreationally trained men (ages
27 +/- 1.7 yr). Each subject performed four trials: 1) Control (fat meal only),
2) Post (exercise 1 h after a fat meal), 3) 1 h-Pre (exercise 1 h before a fat
meal), and 4) 12 h-Pre (exercise 12 h before a fat meal). In each trial, subjects
had a standard fat meal to induce postprandial hypertriglyceridemia. Blood
samples were taken at 0 h (immediately before the fat meal) and at 2, 4, 6, 8,
and 24 h after the meal. In the exercise trials, each subject exercised at 60% of
maximal O2 consumption for 1 h. The results indicated that triglyceride area
under the curve scores in premeal-exercise trials were lower (P < 0. 05) than
those in Post and Control. At 24 h, total high-density lipoprotein (HDL)
cholesterol in the premeal-exercise trials was higher (P < 0.05) than that at 0
h, whereas total HDL-cholesterol was not changed in Control and Post. At 24 h,
HDL subtype 2-cholesterol was higher (P < 0.05) in the premeal-exercise trials
than in Control, which did not differ from Post. These results suggest that
exercising before a fat meal may have a beneficial effect on the triglyceride
response and HDL metabolism, which may blunt atherosclerotic process induced by
the fat meal.
PMID- 9760350
TI - Effect of prolonged, heavy exercise on pulmonary gas exchange in athletes.
AB - During maximal exercise, ventilation-perfusion inequality increases, especially
in athletes. The mechanism remains speculative. We hypothesized that, if
interstitial pulmonary edema is involved, prolonged exercise would result in
increasing ventilation-perfusion inequality over time by exposing the pulmonary
vascular bed to high pressures for a long duration. The response to short-term
exercise was first characterized in six male athletes [maximal O2 uptake
(V(O2)max) = 63 ml x kg-1 x min-1] by using 5 min of cycling exercise at 30, 65,
and 90% V(O2) max. Multiple inert-gas, blood-gas, hemodynamic, metabolic rate,
and ventilatory data were obtained. Resting log SD of the perfusion distribution
(log SDQ) was normal [0.50 +/- 0.03 (SE)] and increased with exercise (log SDQ =
0.65 +/- 0.04, P < 0.005), alveolar-arterial O2 difference increased (to 24 +/- 3
Torr), and end-capillary pulmonary diffusion limitation occurred at 90% V(O2)max.
The subjects recovered for 30 min, then, after resting measurements were taken,
exercised for 60 min at approximately 65% V(O2)max. O2 uptake, ventilation,
cardiac output, and alveolar-arterial O2 difference were unchanged after the
first 5 min of this test, but log SDQ increased from 0.59 +/- 0.03 at 5 min to 0.
66 +/- 0.05 at 60 min (P < 0.05), without pulmonary diffusion limitation. Log SDQ
was negatively related to total lung capacity normalized for body surface area (r
= -0.97, P < 0.005 at 60 min). These data are compatible with interstitial edema
as a mechanism and suggest that lung size is an important determinant of the
efficiency of gas exchange during exercise.
PMID- 9760351
TI - Dynamics of lung collapse and recruitment during prolonged breathing in porcine
lung injury.
AB - Oleic acid (OA) injection, lung lavage, and endotoxin infusion are three commonly
used methods to induce experimental lung injury. The dynamics of lung collapse
and recruitment in these models have not been studied, although knowledge of this
is desirable to establish ventilatory techniques that keep the lungs open. We
measured lung density by computed tomography during breath-holding procedures.
Lung injury was induced with OA, lung lavage, or endotoxin in groups of six
mechanically ventilated pigs. After a stabilization period, repetitive computed
tomography scans of the same slice were obtained during prolonged expirations
with and without positive end-expiratory pressure and during prolonged
inspirations after 5 and 30 s of expiration. Lung collapse and recruitment
occurred mainly within the first 4 s of breath-holding procedures in all three
lung injury models, and some collapse and recruitment occurred even within 0.6 s.
OA-injured lungs were significantly more unstable than lungs injured by
bronchoalveolar lavage or endotoxin infusion. In this experimental setting,
expiration times <0.6 s are required to avoid cyclic alveolar collapse during
mechanical ventilation without extrinsic positive end-expiratory pressure.
PMID- 9760352
TI - Hormonal responses to consecutive days of heavy-resistance exercise with or
without nutritional supplementation.
AB - Nine resistance-trained men consumed either a protein-carbohydrate supplement or
placebo for 1 wk in a crossover design separated by 7 days. The last 3 days of
each treatment, subjects performed resistance exercise. The supplement was
consumed 2 h before and immediately after the workout, and blood was obtained
before and after exercise (0, 15, 30, 45, and 60 min postexercise). Lactate,
growth hormone, and testosterone were significantly (P = 0.05) elevated
immediately postexercise. The lactate response was significantly lower during
supplementation on days 2 and 3. Growth hormone and prolactin responses on day 1
were significantly higher during supplementation. After exercise, testosterone
declined below resting values during supplementation. Cortisol decreased
immediately postexercise on day 1; the response was diminished on days 2 and 3.
Glucose and insulin were significantly elevated by 30 min during supplementation
and remained stable during placebo. Insulin-like growth factor-I was higher
during supplementation on days 2 and 3. These data indicate that protein
carbohydrate supplementation before and after training can alter the metabolic
and hormonal responses to consecutive days of heavy-resistance exercise.
PMID- 9760353
TI - Effects of prior exercise on exercise-induced arterial hypoxemia in young women.
AB - Twenty-eight healthy women (ages 27.2 +/- 6.4 yr) with widely varying fitness
levels [maximal O2 consumption (VO2 max), 31-70 ml . kg-1 . min-1] first
completed a progressive incremental treadmill test to VO2 max (total duration,
13.3 +/- 1.4 min; 97 +/- 37 s at maximal workload), rested for 20 min, and then
completed a constant-load treadmill test at maximal workload (total duration, 143
+/- 31 s). At the termination of the progressive test, 6 subjects had maintained
arterial PO2 (PaO2) near resting levels, whereas 22 subjects showed a >10 Torr
decrease in PaO2 [78.0 +/- 7.2 Torr, arterial O2 saturation (SaO2), 91.6 +/-
2.4%], and alveolar-arterial O2 difference (A-aDO2, 39.2 +/- 7.4 Torr). During
the subsequent constant-load test, all subjects, regardless of their degree of
exercise-induced arterial hypoxemia (EIAH) during the progressive test, showed a
nearly identical effect of a narrowed A-aDO2 (-4.8 +/- 3.8 Torr) and an increase
in PaO2 (+5.9 +/- 4.3 Torr) and SaO2 (+1.6 +/- 1.7%) compared with at the end
point of the progressive test. Therefore, EIAH during maximal exercise was
lessened, not enhanced, by prior exercise, consistent with the hypothesis that
EIAH is not caused by a mechanism which persists after the initial exercise
period and is aggravated by subsequent exercise, as might be expected of exercise
induced structural alterations at the alveolar-capillary interface. Rather, these
findings in habitually active young women point to a functionally based mechanism
for EIAH that is present only during the exercise period.
PMID- 9760354
TI - Size constraints of telemeters in rats.
AB - This study was designed to determine the maximum-size subcutaneous telemeter that
would enable long-term and multichannel data collection in a 170-g rat for 90
days. In phase 1, rats with implants weighing 5 (2.5 cm3), 15 (7.5 cm3), 25 (12.5
cm3), 35 (17.5 cm3), or 45 (22.5 cm3) g were compared with sham-operated (SOC)
and nonoperated (NOC) control animals. Severe skin lesions, seromas, and lower
growth rates were observed in rats having implants >/=35 g. Thus, in phase 2,
rats implanted with 23.5 g (17.5 cm3; 11-g active telemeter and 12.5-g implant)
were compared with rats implanted with 11 g (6 cm3; telemeter only) and with the
SOC and NOC groups. No differences were found among implanted groups in mean
arterial pressure (MAP), heart rate (HR), subcutaneous temperature, or
spontaneous activity under standard housing conditions. All groups were more
active and had a higher MAP during the dark than the light phase of the daily
cycle. During 2 h of cold exposure (3 degreesC), both telemetered groups
exhibited similar changes in HR, MAP, temperature, and activity levels. Adrenal
glands were larger in the 23.5-g group (51 +/- 1.6 mg) than in the SOC (46 +/-
1.0 mg) and the NOC groups (41 +/- 2.0 mg). No other significant differences were
found in organ, muscle, or bone weights. These data verify the feasibility of
using 23.5-g (17.5 cm3) subcutaneous telemeters for chronic recordings in young
adult rats.
PMID- 9760356
TI - Determining bone and total body mineral content from body density and
bioelectrical response spectroscopy.
AB - We hypothesized that one could assess total body mineral (TBM) and bone mineral
content (BMC) from measurements of body density and bioelectrical response
spectroscopy (BRS)-determined total body water by using a three-compartment (3C)
model. We compared TBM and BMC computed from measurements of water (2H2O dilution
or BRS) and body density (underwater weighing) with [4-compartment (4C)] and
without (3C) mineral (dual X-ray absorptiometry) in 15 women and 16 men. BRS used
multifrequency or single-frequency estimates of water. Mean differences between
the 3C and 4C models ranged from -6.1 to 2.2%. Correlations between models were
0.82-0.91. Standard errors of the estimate of 8.5-9.3% were within the range of
those previously reported, i.e., 4.9-13%. Use of BRS did not significantly
decrease the strength of the correlations between the models. A significant mean
difference (only in women) was found only with 3C single-frequency BRS estimates
of TBM and BMC. We concluded that investigators can assess TBM and BMC 3C
multifrequency BRS estimates in men and women.
PMID- 9760355
TI - Time course of active and passive liquid and solute movement in the isolated
perfused rat lung model.
AB - The isolated perfused rat lung model (IL) is used to study alveolar epithelial
transport properties. Most of the previous studies have been done over a short
period of time and have not used the same preparation as a control and
intervention group. We evaluated whether the IL preparation could be used for a
prolonged period of time (5 h) and studied the rates of active Na+ transport,
lung liquid clearance, and passive movement of solutes. Active Na+ transport and
lung liquid clearance were stable from 1 to 5 h. The passive movement of small
solutes (Na+, mannitol) did not change significantly, and albumin movement
increased slightly at the fifth hour. Total RNA isolated from IL after 5 h was
intact, and the Na+-K+-ATPase activity in alveolar type II cells isolated at the
end of 5-h experiments was equal to Na+-K+-ATPase function from freshly isolated
alveolar type II cells. Finally, we measured the stimulatory effect of the beta
adrenergic-agonist terbutaline and the inhibitory effect of the Na+-K+-ATPase
antagonist ouabain by using the same animal as a control. Accordingly, the
isolated perfused lung model is functionally stable for at least 5 h, and it
could be utilized to evaluate the effect of different interventions by using the
same preparation.
PMID- 9760357
TI - Effects of hindlimb contraction on pressor and muscle interstitial metabolite
responses in the cat.
AB - We used the microdialysis technique to measure the interstitial concentration of
several putative metabolic stimulants of the exercise pressor reflex during 3-
and 5-Hz twitch contractions in the decerebrate cat. The peak increases in heart
rate and mean arterial pressure during contraction were 20 +/- 5 beats/min and 21
+/- 8 mmHg and 27 +/- 9 beats/min and 37 +/- 12 mmHg for the 3- and 5-Hz
stimulation protocols, respectively. All variables returned to baseline after 10
min of recovery. Interstitial lactate rose (P < 0. 05) by 0.41 +/- 0.15 and 0.56
+/- 0.16 mM for the 3- and 5-Hz stimulation protocols, respectively, and were not
statistically different from one another. Interstitial lactate levels remained
above (P < 0.05) baseline during recovery in the 5-Hz group. Dialysate phosphate
concentrations (corrected for shifts in probe recovery) rose with stimulation (P
< 0.05) by 0.19 +/- 0.08 and 0.11 +/- 0.03 mM for the 3- and 5-Hz protocols.
There were no differences between groups. The resting dialysate K+ concentrations
for the 3- and 5-Hz conditions were 4.0 +/- 0.1 and 3.9 +/- 0.1 meq/l,
respectively. During stimulation the dialysate K+ concentrations rose steadily
for both conditions, and the increase from rest to stimulation (P < 0.05) was
0.57 +/- 0.19 and 0.81 +/- 0.06 meq/l for the 3- and 5-Hz conditions,
respectively, with no differences between groups. Resting dialysate pH was 6.915
+/- 0.055 and 6.981 +/- 0.032 and rose to 7.013 (P < 0.05) and 7.053 (P < 0.05)
for the 3- and 5-Hz conditions, respectively, and then became acidotic (6. 905, P
< 0.05) during recovery (5 Hz only). This study represents the first time
simultaneous measurements of multiple skeletal muscle interstitial metabolites
and pressor responses to twitch contractions have been made in the cat. These
data suggest that interstitial K+ and phosphate, but not lactate and H+, may
contribute to the stimulation of thin fiber muscle afferents during contraction.
PMID- 9760358
TI - Clinical evaluation of two desensitizing agents for use under Class 5 silver
amalgam restorations.
AB - STATEMENT OF PROBLEM: Postoperative sensitivity is sometimes reported to be a
clinical problem after placement of silver amalgam restorations. PURPOSE: This
study compared postoperative sensitivity of Class 5 caries restored with amalgam
restorations and Copalite or DentinBloc cavity liners. MATERIAL AND METHODS: At
least 1 pair of amalgam restorations were placed in each of 16 patients and
tested for sensitivity at 5 time periods. RESULTS: Sensitivity was significantly
less with DentinBloc cavity liner (P < .05) at 24 hours, and 2 and 4 weeks. There
was a directional but nonsignificant effect (P > .05) in favor of DentinBloc
cavity liner at 1 and 16 weeks. CONCLUSION: DentinBloc cavity liner was more
effective than Copalite cavity liner in reducing sort term postoperative
sensitivity for amalgam restorations.
PMID- 9760359
TI - Necessity of bevels for box only Class II composite restorations.
AB - STATEMENT OF PROBLEM: The tooth preparation of a bevel is recommended to improve
marginal quality of a composite restoration. However, in small Class II
restorations, it is unclear if a bevel also contributed to a better marginal fit.
PURPOSE: This study investigated the influence of tooth preparation design on
microleakage of minimal posterior Class II composite restorations. MATERIAL AND
METHODS: Box-shaped Class II tooth preparations for posterior composite
restorations in maxillary premolars were restored with a total etch technique.
The tooth preparations were beveled or non-beveled and the box prepared at a
right angle cervically or additionally excavated. The facial and lingual box
margins were also either beveled or unbeveled. The teeth were thermocycled and
immersed in a dye solution. After sectioning specimens, dye penetration at the
facial and palatal margins was recorded. RESULTS: A bevel-reduced microleakage
both at the cervical and ascending walls. Enamel cracks were observed along
certain unbeveled margins as recorded in this study. The additional excavation
did not contribute to reduction of microleakage. CONCLUSIONS: Tooth preparation
of a bevel is recommended for an optimal marginal seal in small box-type Class II
composite restorations.
PMID- 9760360
TI - Dental luting agents: A review of the current literature.
AB - STATEMENT OF PROBLEM: The practice of fixed prosthodontic has changed
dramatically with the introduction of innovative techniques and materials.
Adhesive resin systems are examples of these changes that have led to the
popularity of bonded ceramics and resin-retained fixed partial dentures. Today's
dentist has the choice of a water-based luting agent (zinc phosphate, zinc
polycarboxylate, glass ionomer, or reinforced zinc oxide-eugenol) or a resin
system with or without an adhesive. Recent formulations of glass ionomer luting
agents include resin components (resin-modified glass ionomers), which are
increasingly popular in clinical practice. PURPOSE: This review summarizes the
research on these systems with the goal of providing information that will help
the reader choose the most suitable material. MATERIAL: The scientific studies
have been evaluated in relation to the following categories: (1)
biocompatibility, (2) caries or plaque inhibition, (3) microleakage, (4) strength
and other mechanical properties, (5) solubility, (6) water sorption, (7)
adhesion, (8) setting stresses, (9) wear resistance, (10) color stability, (11)
radiopacity, (12) film thickness or viscosity, and (13) working and setting
times. In addition, guidelines on luting-agent manipulation are related to
available literature and include: (1) temporary cement removal, (2) smear layer
removal, (3) powder/liquid ratio, (4) mixing temperature and speed, (5) seating
force and vibration, and (6) moisture control. Tables of available products and
their properties are also presented together with current recommendations by the
authors with a rationale.
PMID- 9760361
TI - A simple method of increasing the adhesion between resinous cements and tinplated
gold alloys: a pilot study.
AB - PURPOSE: This study: (1) tested 2 BIS-GMA resinous cements on tinplated gold
alloy surfaces with shearing forces to record their bond strengths, and (2)
determined whether storage of the tinplated surfaces in water before cementation
affected initial bond strengths. MATERIAL AND METHODS: The bond strengths of
Panavia Ex and Panavia 21 resinous cements to tinplated Type III gold alloy were
measured when subjected to shearing forces. Specimens were luted in pairs with
these cements. In one group, the cementation was performed after tinplating
procedures. In the other group, tinplated alloy surfaces were first stored in
water at 37 degrees C for 48 hours before cementation. RESULTS: A 3-fold increase
in bond strength values was recorded for tinplated specimens stored in water
before cementation with both cements, these differences were statistically
significant. Storage of the specimen in water before cementation appeared to
increase resistance of the alloy resin bond to failure with application of
shearing forces. CONCLUSION: This pilot study suggested that it would be
advantageous to age tinplated gold alloy surfaces in water for 48 hours before
cementation.
PMID- 9760362
TI - Shear bond strength of a titanium reinforced core material after using multistep
and single-step bonding agents.
AB - STATEMENT OF PROBLEM: Recently introduced single-step bonding agents reduce the
number of steps involved in the bonding process. Nevertheless, there are few
studies on the bond strengths obtained with these new systems. PURPOSE: This in
vitro study evaluated the shear bond strength of a titanium-reinforced cores
bonded with 5 multistep bonding systems (ScotchBond Multi-Purpose, OptiBond, All
Bond-2, Tenure, and ProBond) and 5 single-step bonding systems (Single-Bond,
OptiBond Solo, One-Step, Tenure Quik, and Prime & Bond 2.1). MATERIAL AND
METHODS: The experiment was divided into 10 groups with 10 specimens per group.
The shear bond strengths were evaluated after 24 hours on an MTS universal
testing machine with a crosshead speed of 6.35 mm/minute. RESULTS: A 2-way ANOVA
showed that All Bond-2 and One-Step recorded the highest means and differed
significantly from the Den-Mat systems (Tenure A&B and Tenure Quik), the Kerr
systems (OptiBond and Opti-Solo), and the Caulk systems (ProBond and Prime & Bond
2.1). ProBond and Prime & Bond 2.1 bonding systems had the lowest mean and
differed from the 3 other brands. Tenure A&B and Tenure Quik bonding systems and
OptiBond and Opti-Solo bonding systems did not differ from one another.
CONCLUSION: The single-step bonding agents did not produce an improvement in
shear bond strengths. The wide range of shear bond strength reported for the
single-step systems appeared to indicate that these bonding systems are technique
sensitive.
PMID- 9760363
TI - Development and clinical applications of a light-polymerized fiber-reinforced
composite.
AB - STATEMENT OF PROBLEM: After 0 years of intermittent reports in the literature,
the use of fiber reinforcement is just now experiencing rapid expansion in
dentistry. PURPOSE: This article describes the development and use of a
continuous, unidirectional fiber reinforced composite as a framework for the
fabrication of fixed prostheses. METHODS: By using various matrix materials and
fibers, a number of fiber-reinforced composite formulations were evaluated with
the goal of creating a system with optimized mechanical properties and handling
characteristics. Fiber-reinforced composite based on a light polymerized BIS-GMA
matrix has been used clinically to make 2-phase prostheses comprised of an
internal glass fiber-reinforced composite substructure covered by a particulate
composite. The clinical and laboratory procedures required for the fabrication
and use of reinforced composite fixed prostheses are described for laboratory
fabricated complete or partial coverage fixed prosthesis and chairside
prosthesis. RESULTS: Although additional clinical experience is needed, fiber
reinforced composite materials can be used to make metal-free prostheses with
excellent esthetic qualities.
PMID- 9760364
TI - Thickness of the remaining enamel after the preparation of cingulum rest seats on
maxillary canines.
AB - PURPOSE: This study evaluated the level of tissue removal that takes place on
enamel and dentin during cingulum rest seat preparation. MATERIAL AND METHODS: A
quantitative evaluation of the thickness of the remaining enamel of cingulum seat
preparations to receive removable partial denture rests was carried out in 20
maxillary canines with a light optical microscope. RESULTS: Thirty percent of the
preparations were overextended into dentinal tissue, and 85% had depths that were
insufficient to receive rests.
PMID- 9760365
TI - Retention of prefabricated attachments for implant stabilized overdentures in the
edentulous mandible: an in vitro study.
AB - STATEMENT OF PROBLEM: Bar and stud attachments are widely used to stabilize
overdentures on implants in the mandible. There is strong evidence that retention
of the attachment is an important factor for a patient's satisfaction. PURPOSE:
This study describes retentive forces and wear of commercially available
attachments of 4 implant systems (31, IMZ, Nobel Biocare, ITI Straumann) and 2
magnets (Steco). METHODS: Forces while removing the keyway portion of an
attachment in its path of insertion were measured with a platform load cell. A
total of 15,000 removals were performed to simulate fatigue. RESULTS: Retentive
forces ranged between 3 and 85 N. The fatigue test revealed an initial increase
of forces with some attachments. After 15,000 cycles, most of the attachments
showed little loss of retention compared with the initial retentive forces. It is
suggested that conventional fatigue tests with application of axial loads do no
simulate clinical fatigue adequately.
PMID- 9760366
TI - Feedback control during mastication of solid food textures--a clinical
experimental study.
AB - STATEMENT OF PROBLEM: On the basis of animal experiments, it has been
hypothesized that the dynamics of food reduction are controlled by peripheral
receptors. Studies on this subject in human beings are rare. PURPOSE: This study
investigated the influence of periodontal and joint proprioceptors on mastication
in human beings. MATERIAL AND METHODS: Both jaw joints and the chewing-side teeth
were consecutively anesthetized in a 6-person panel by chewing wine gum. The
effects on the kinematics, chewing force, and electromyographic activity were
measured. RESULTS: The results substantiate a positive feedback of periodontal
receptors for chewing force control. A substantial influence of joint receptors
on movement control could not be found. CONCLUSION: Despite the absence of
proprioception in both jaw joints and the periodontal receptors in the chewing
side, the characteristics of the measured kinematic and dynamic values remained
essentially unchanged.
PMID- 9760368
TI - Computer-assisted milling of dental restorations using a new CAD/CAM data
acquisition system.
AB - BACKGROUND: Recent technologic innovations have created possibilities for
restorative dentistry, such as computer-aided design and computer-aided
manufacturing (CAD/CAM). PURPOSE: This article presents a new CAD/CAM process
that has been developed for the fabrication of dental restorations. METHODS: This
process uses an improved imaging technique, successfully applied in other
industries. Imaging is accomplished with 2-dimensional line grids projected onto
an object, which allows for a mathematical reproduction of prepared and
unprepared tooth surfaces, including those that are outside the direct line of
light. The relative position of the sensor to the surface of the object is
controlled automatically. CONCLUSIONS: This system, which is undergoing clinical
testing, allows the generation of various types of highly accurate dental
restorations (inlays, onlays, crown, and fixed partial dentures) from a number of
different materials. Acquired digitized data points are directly translated from
the sensor to the electronic controls of the milling machine to provide various
manufacturing possibilities, including copy milling and accurate reproduction of
occlusal tooth surfaces in various materials.
PMID- 9760367
TI - Marginal fit and surface roughness of crowns made with an accelerated casting
technique.
AB - STATEMENT OF PROBLEM: Conventional investing and casting techniques following the
manufactures' recommendations are time-consuming. Accelerated casting techniques
have been reported, but their accuracy has not been adequately studied for
complete crown castings. PURPOSE: This study evaluated the marginal fit and
surface roughness of complete crowns made with a conventional and an accelerated
casting technique. MATERIALS AND METHODS: Part I of the study determined the mean
time interval required for each investment to reach its maximum exothermic
setting reaction temperature. Part II determined the marginal discrepancy of
standardized complete crowns cast in a high noble metal ceramic alloy, with the
use of four phosphate-bonded investments. A conventional technique (as
recommended by the manufacturer) was compared with an accelerated technique that
used 13- to 17-minute bench set time (as determined in part 1 for each
investment)_ and 15-minute wax elimination cycle in a 815 degrees C (1500 degrees
F) preheated furnace. Part III evaluated the surface roughness of castings made
with the same techniques as in part II. RESULTS: For the marginal discrepancy and
surface roughness, crowns fabricated with the accelerated casting technique were
not significantly (P > 0.05) different from those fabricated with the
conventional technique. CONCLUSION: The accelerated casting technique described
in this study could be a vital alternative to the time-consuming conventional
techniques.
PMID- 9760369
TI - Comparison of bond strengths of three denture base resins to treated nickel
chromium-beryllium alloy.
AB - PURPOSE: In-vitro bond strengths of 3 denture base resins (Trutone, Lucitone 199,
and Triad) to a nickel-chromium-beryllium removable partial denture alloy
(Ticonium) were tested with 3 surface pretreatments: sandblast, acid etch, and
Rocatec (silica blasting), with or without primers (Dentsply, CR inlay cement,
and Super Bond). MATERIAL AND METHODS: Lucitone 199 denture base resin bonded to
the nonprimed sandblasted alloy specimen served as the control group. Alloy
specimens were prepared, surface treated, and primed or not primed with primer.
The treated specimens were then packed and processed with the denture base resin.
Bonded specimens were stored in the distilled water at 37 degrees C for 24 hours,
and then debonded in tension. The force at which the bond failed was noted, and
bond strength was calculated in megapascals (MPa). Five replications for each
condition (180 specimens total) were tested. RESULTS: Significant differences in
bond strength were observed with primer, the most important factor, followed by
pretreatment and denture base resin. Without primer for all 3 denture base
resins, the Met-Etch and Rocatec treated group showed significantly higher bond
strengths than the sandblasted groups. For Trutone denture base resin, nonprimed
treated groups produced significantly higher bond strength than those for the
other 2 denture base resin, nonprimed treated groups produced significantly
higher bond strength than those for the other 2 denture base resins. The control
group had zero bond strength. For Dentsply primer, the Rocatec treated group
bonded to Lucitone 199 resin produced the highest bond strength value (14.8 +/-
1.8 MPa). For CR inlay cement, the Met-Etch and Rocatec treated groups for
Lucitone denture base resin demonstrated the highest bond strength (19.3 +/- 4.8
MPa, and 19.3 +/- 1.8 MPa, respectively). For super Bond primer, the Met-Etch
treated group for Trutone resin demonstrated the highest bond strength (19.8 +/-
6.2 MPa). CONCLUSIONS: Without primer, the control had the lowest bond strength
(0 MPa), and the Trutone groups showed the highest bond strength (11.7 +/- 4.1
MPa). Met-Etch and Rocatec treated groups produced higher bond strengths than the
sandblasted groups. The primed specimens demonstrated significantly higher bond
strengths than nonprimed specimens, except for Trutone resin, for which primed
specimens produced lower bond strengths than the nonprimed specimens.
PMID- 9760371
TI - An esthetically attractive twin-flex clasp for removable partial dentures.
AB - The cosmetic appearance of a removable partial denture is of great importance to
both the patient and the dentist. Traditional facial clasp arms are usually
unsightly. Other options are expensive and/or technically difficult, and may
require time-consuming maintenance. Furthermore, when these clasps are broken,
replacement of the entire removable partial denture may be required. This article
describes a procedure for making a simple but effective twin-flex clasp. The
clasp has excellent esthetics and can be readily adjusted or replaced.
PMID- 9760370
TI - The effect of prosthodontic treatment on alveolar bone loss: a review of the
literature.
AB - STATEMENT OF PROBLEM: Complete, fixed partial, removable partial, and implant
supported dentures have been used to comfortably and esthetically replace missing
teeth. However, it is not certain what effect these prostheses have on the
residual ridge. PURPOSE: This article compares various prosthetic treatments to
restore completely and partially edentulous mouths for their ability to preserve
residual alveolar bone. MATERIAL AND METHODS: A review of the literature was
performed to discuss the effects of tooth replacement on residual alveolar bone.
RESULTS: The literature seems to indicate that the presence of a dental
prosthesis affects the size and form of the residual alveolar ridge and bone.
CONCLUSION: An implant-supported fixed prosthesis to restore missing teeth in
partially or completely edentulous jaws seems to be the best means of preserving
residual alveolar bone.
PMID- 9760372
TI - A new gingival retraction impression system for a one-stage root-form implant.
AB - Displacement of soft tissue adjacent to an implant abutment is arduous.
Currently, gingival retraction cord is used before making an impression for
cement-retained implant restoration. This article presents a new impression
system for a cementable abutment/implant. The advantages of a cement-retained
implant crown are described. This system provides efficient and accurate
impressions.
PMID- 9760373
TI - The occlusal plane indicator: a new device for determining the inclination of the
occlusal plane.
AB - Accurate determination of the inclination of the occlusal plane is important in a
number of situations, and includes confirming the correct development of the
dentition in children, providing a basis for nonanatomic tooth design in the
preparation of fixed prostheses, and assisting in decisions as to whether to
perform intrusions or extrusions. This article describes a simple device for
determination of the inclination of the occlusal plane.
PMID- 9760374
TI - A new fully adjustable articulator system and procedure.
AB - This article presents a simple and efficient articulator to help with the
registration of maxillomandibular relationships, mounting casts, and subsequent
perfection of the occlusal scheme for various types of prosthodontic
restorations. The system (Individual Anatomo-Physiological system), which is
composed of the articulator and recommended procedures, allows for registration
of positions and trajectories of the mandible at the level of the patient's
occlusal plane. It is used to accurately transfer the records to the articulator.
A luminous signal shows the correct centric occlusal relationship and vertical
dimension, in both clinical and laboratory procedures. Interocclusal records are
used for semiadjustment of the articulator for provisional restorations and
stereographic records are used for full adjustment of the articulator for
definitive treatment.
PMID- 9760375
TI - It's never too late to quit.
PMID- 9760376
TI - Making sense of self-mutilation.
PMID- 9760378
TI - Better medication compliance in teenagers with ADHD.
PMID- 9760377
TI - Chronic headaches--more than just an aching head?
PMID- 9760379
TI - Childhood trauma and adult illness.
PMID- 9760380
TI - Updating what we know about depression in adolescents.
AB - 1. Despite an 80% increase in prescriptions written for antidepressants for the
treatment of pediatric depression, little empirical research has been done on the
effects of antidepressant therapy on children and adolescents. 2. What little
research has been done does not support the efficacy of antidepressants use in
children. Moreover, some antidepressants may actually be harmful to pediatric
populations. 3. Nurses have an obligation to keep abreast of the latest research
findings in the literature because the knowledge base changes daily.
PMID- 9760381
TI - The 5 R's of becoming a psychiatric nurse practitioner: rationale, readying,
roles, rules, and reality.
AB - 1. Psychiatric nurse practitioners (NPs) are advanced practice registered nurses
who deliver primary mental health and psychiatric care to clients and families.
2. Psychiatric NP curricula include advanced health assessment, pathology,
pharmacology, NP role development, and psychiatric-mental health content, such as
diagnosing and managing mental illnesses, providing therapies, and promoting
mental health. 3. The degree of prescriptive autonomy of psychiatric NPs is
determined by each state's Nurse Practice Act.
PMID- 9760383
TI - Expertise in caring: a source of power.
AB - 1. Caring generates power in relationships with patients and helps them to
evolve. 2. Caring is more than an emotional response. It is acting in ways that
demonstrate that people, relationships, and issues are important. 3. Continuity
of care providers across settings help yield positive outcomes for patients.
PMID- 9760382
TI - College students' AIDS risk perception.
AB - 1. Students in this study appraised their AIDS risk using their sexual and drug
use behavior as criteria, which accurately reflects their knowledge of HIV
transmission. 2. AIDS risk perceptions were not always congruent with the
students' self-reported sexual and drug use behavior. Some students reporting
high-risk behavior perceived their AIDS risk as "nil" or "small." 3. Perceived
riskiness of behavior increased as distance from the students increased. The
students viewed their friends' AIDS risk as moderately greater than their own
risk and their peers' risk even greater.
PMID- 9760384
TI - Listening to the voice hearers.
PMID- 9760385
TI - Audacious goals for health and biomedical informatics in the new millennium.
AB - The 1998 Scientific Symposium of the American College of Medical Informatics
(ACMI) was devoted to developing visions for the future of health care and
biomedicine and a strategic agenda for health and biomedical informatics in
support of those visions. This symposium focus was prompted by the many major
changes currently underway in health care delivery, education, and research, as
well as in our health and biomedical enterprises, and by the constantly
increasing role of information technology in both shaping and enabling these
changes. The three audacious goals developed for 2008 are a virtual health care
databank, a national health care knowledge base, and a personal clinical health
record.
PMID- 9760386
TI - Then and now and when.
AB - Since the 1970s, it has been clear that the health community needs to develop a
health care system that matches a person's needs with the expertise and
technology to address those needs. The logical solution is a multi-tiered system.
In such a system, physicians would provide second- and third-tier services and
other health professionals would provide first- and second-tier services. Medical
informatics should take on the challenge of supporting the decision to triage
patients from one tier of service to another. Triage decisions are different from
other decisions in health sciences because they take place early in the life of a
problem, when little information is available, and can be made safely if adjusted
to tolerate erring on the side of referral.
PMID- 9760387
TI - Directions for clinical research and genomic research into the next decade:
implications for informatics.
AB - Medical informatics is defined largely by its host disciplines in clinical and
biological medicine, and to project the agenda for informatics into the next
decade, the health community must envision the broad context of biomedical
research. This paper is a sketch of this vision, taking into account pressures
from changes in the U.S. health care system, the need for more objective
information on which to base health care decisions, and the accelerating progress
and clinical impact of genomics research. The lessons of modern genomics research
demonstrate the power of computing and communication tools to facilitate rapid
progress through the adoption of open community standards for information
exchange and collaboration. While aspects of this vision are speculative, it
seems clear that the core agenda for informatics must be the development of
interoperating systems that can facilitate the secure gathering, interchange, and
analysis of high-quality information and can gain leverage from worldwide
collaboration in advancing and applying new medical knowledge.
PMID- 9760389
TI - (Bio) medical informatics in the next decade.
AB - Even though medical informatics is most often viewed from the perspective of its
host disciplines in clinical and biologic medicine, it has an identity and agenda
of its own. This paper is an attempt to promote discussion about the long-term
role and agenda for medical informatics as a discipline into the next decade. The
discussion has two main lines of argument, one about the "engineering" goals of
informatics and the other about the "basic research" goals. These are, of course,
influenced by ongoing of developments in computing, communications, and software
infrastructures, but informatics is now mature enough that many of its goals
transcend these changes.
PMID- 9760388
TI - The networked health enterprise: a vision for 2008.
AB - Informatics and information technology hold the promise of a consumer-centered
health enterprise--one that provides quality care at a cost society is willing to
pay; one where need-based, adaptive, competency-based learning results in cost
effectiveness of health education; one where team-based health and learning on
demand, coupled with monitoring of process outcomes and network access to
expertise, guarantee quality. The barriers to this promise are the professional
guilds, the cross-subsidies that support the health enterprise of 1998, and the
lack of respect for privacy. Collectively, the informatics community needs to
develop a compelling vision that will galvanize the health community to action.
If the health community does not step up to this challenge, consumers will take
advantage of disintermediation. Empowered by the network, they will go outside
the system into hands that meet their needs.
PMID- 9760390
TI - Representing thoughts, words, and things in the UMLS.
AB - The authors describe a framework, based on the Ogden-Richards semiotic triangle,
for understanding the relationship between the Unified Medical Language System
(UMLS) and the source terminologies from which the UMLS derives its content. They
pay particular attention to UMLS's Concept Unique Identifier (CUI) and the sense
of "meaning" it represents as contrasted with the sense of "meaning" represented
by the source terminologies. The CUI takes on emergent meaning through linkage to
terms in different terminology systems. In some cases, a CUI's emergent meaning
can differ significantly from the original sources' intended meanings of terms
linked by that CUI. Identification of these different senses of meaning within
the UMLS is consistent with historical themes of semantic interpretation of
language. Examination of the UMLS within such a historical framework makes it
possible to better understand the strengths and limitations of the UMLS approach
for integrating disparate terminologic systems and to provide a model, or
theoretic foundation, for evaluating the UMLS as a Possible World--that is, as a
mathematical formalism that represents propositions about some perspective or
interpretation of the physical world.
PMID- 9760391
TI - A case study of the evolving software architecture for the FDA generic drug
application process.
AB - This primary goal of this project was to develop a software architecture to
support the Food and Drug Administration (FDA) generic drug application process
by making it more efficient and effective. The secondary goal was to produce a
scalable, modular, and flexible architecture that could be generalized to other
contexts in interorganizational health care communications. The system described
here shows improvements over the old system for the generic drug application
process for most of the defined design objectives. The modular, flexible design
that produced this new system offers lessons for the general design of
distributed health care information systems and points the way to robust
application frameworks that will allow practical development and maintenance of a
distributed infrastructure.
PMID- 9760392
TI - Arizona Telemedicine Program: implementing a statewide health care network.
AB - The Arizona Telemedicine Program was established in July 1996 by the Arizona
state legislature. The organizational center for the program is the Arizona
Health Sciences Center in Tucson. Key goals for the program include increased
access to specialty services for rural, underserved populations; development of
cost-effective telemedicine services; and expansion of opportunities for
education of health professionals in rural areas. The program provides several
levels of services based on both store-and-forward and real-time interactive
applications. The telecommunication infrastructures is provided by two methods:
The first is a private asynchronous transfer mode network established and
operated by program personnel. The second is dial-up access via the public
switched telephone network. After an extensive period of organization and vendor
evaluations, most of the private network was implemented between June and
December 1997. This paper describes experiences establishing the asynchronous
transfer mode network.
PMID- 9760393
TI - The structure of medical informatics journal literature.
AB - OBJECTIVE: Medical informatics is an emergent interdisciplinary field described
as drawing upon and contributing to both the health sciences and information
sciences. The authors elucidate the disciplinary nature and internal structure of
the field. DESIGN: To better understand the field's disciplinary nature, the
authors examine the intercitation relationships of its journal literature. To
determine its internal structure, they examined its journal cocitation patterns.
MEASUREMENTS: The authors used data from the Science Citation Index (SCI) and
Social Science Citation Index (SSCI) to perform intercitation studies among
productive journal titles, and software routines from SPSS to perform
multivariate data analyses on cocitation data for proposed core journals.
RESULTS: Intercitation network analysis suggests that a core literature exists,
one mark of a separate discipline. Multivariate analyses of cocitation data
suggest that major focus areas within the field include biomedical engineering,
biomedical computing, decision support, and education. The interpretable
dimensions of multidimensional scaling maps differed for the SCI and SSCI data
sets. Strong links to information science literature were not found. CONCLUSION:
The authors saw indications of a core literature and of several major research
fronts. The field appears to be viewed differently by authors writing in journals
indexed by SCI from those writing in journals indexed by SSCI, with more emphasis
placed on computers and engineering versus decision making by the former and more
emphasis on theory versus application (clinical practice) by the latter.
PMID- 9760395
TI - Recovery of Sarcocystis oocysts from a free-ranging wild dog (Lycaon pictus)
PMID- 9760396
TI - Elbow dysplasia in the dog: pathophysiology, diagnosis and control.
AB - Elbow dysplasia is a non-specific term denoting abnormal development of the
elbow. Elbow dysplasia encompasses the clinical and radiographic manifestation of
ununited anconeal process, fragmented medical coronoid process, osteochondritis
dissecans, erosive cartilage lesions and elbow incongruity. The net result is
elbow arthrosis, which may be clinically inapparent or result in marked lameness.
These conditions may be diagnosed by means of routine or special radiographic
views and other imaging modalities, or the precise cause of the arthrosis or
lameness may remain undetermined. Breeds most commonly affected are the
rottweiler, Bernese mountain dog, Labrador and golden retriever and the German
shepherd dog. Certain breeds are more susceptible to a particular form of elbow
dysplasia and more than 1 component may occur simultaneously. The various
conditions are thought to result from osteochondrosis of the articular or physeal
cartilage that results in disparate growth of the radius and ulna. Heritability
has been proven for this polygenic condition and screening programmes to select
suitable breeding stock have been initiated in several countries and have
decreased the incidence of elbow dysplasia.
PMID- 9760394
TI - Representing clinical guidelines in GLIF: individual and collaborative expertise.
AB - OBJECTIVE: An evaluation of the cognitive processes used in the translation of a
clinical guideline from text into an encoded form so that it can be shared among
medical institutions. DESIGN: A comparative study at three sites regarding the
generation of individual and collaborative representations of a guideline for the
management of encephalopathy using the GuideLine Interchange Format (GLIF)
developed by members of the InterMed Collaboratory. MEASUREMENTS: Using theories
and methods of cognitive science, the study involves a detailed analysis of the
cognitive processes used in generating representations in GLIF. The resulting
process-outcome measures are used to compare subjects with various types of
computer science or clinical expertise and from different institutions. RESULTS:
Consistent with prior studies of text comprehension and expertise, the
variability in strategies was found to be dependent on the degree of prior
experience and knowledge of the domain. Differing both in content and structure,
the representations developed by physicians were found to have additional
information and organization not explicitly stated in the guidelines, reflecting
the physicians' understanding of the underlying pathophysiology. The computer
scientists developed more literal representations of the guidelines; addition
were mostly limited to specifications mandated by the logic of GLIF itself.
Collaboration between physicians and computer scientists resulted in consistent
representations that were more than the sum of the separate parts, in that both
domain-specific knowledge of medicine and generic knowledge of guideline
structure were seamlessly integrated. CONCLUSION: Because of the variable
construction of guideline representations, understanding the processes and
limitations involved in their generation is important in developing strategies to
construct shared representations that are both accurate and efficient. The
encoded guidelines developed by teams that include both clinicians and experts in
computer-based representations are preferable to those developed by individuals
of either type working alone.
PMID- 9760397
TI - Lack of susceptibility of Ehrlichia canis to imidocarb dipropionate in vitro.
AB - In vitro antimicrobial susceptibility testing was used to compare the efficacy of
imidocarb dipropionate and doxycycline on the growth of Ehrlichia canis in DH82
cell cultures. Over a 9-day period there were no significant differences (p <
0.01) in the growth of E. canis in untreated control wells and those to which
imidocarb dipropionate was added at 1.2, 2.4, 4.8 or 12 micrograms/ml for the 1st
3 days. Average infection rates rose from 50 to 55% on day 0 to 100% on day 5 or
6. Doxycycline at 1 microgram/ml had residual or rickettsiocidal activity against
E. canis with the average percentages of DH82 cells infected declining from 51 to
24% while the organism was exposed to the drug (3 days) and from 21 to 2% in the
6 days following removal of the drug from the cell culture medium.
PMID- 9760398
TI - Urinary excretion of diethylstilbestrol in the ostrich.
AB - Stilboestrol tablets (20 x 1 mg) were given to 4 ostriches. Urine was collected
over a period of 8 days and stored frozen at-20 degrees C pending analysis.
Analyses were performed on a gas chromatograph-mass selective detector for the
presence of parent compound and/or metabolites. Diethylstilbestrol and its
metabolite, dienestrol, were detected in urine; dienestrol only for 1 day but
diethylstilbestrol for 8 days after administration. Residue analysis for the use
of diethylstilbestrol as growth promoter can be performed on the urine of
ostriches by scanning for parent compound only since it can be detected longer
than the metabolite.
PMID- 9760399
TI - Prevalence of gastro-oesophageal ulcers in grower-finisher pigs in the northern
province of South Africa.
AB - Ulceration of the gastric pars oesophagea is a common problem in intensive pig
production that is often detected at slaughter. A survey was carried out at the
Pietersburg abattoir in the Northern Province during a 6-month period. In total,
4320 pig stomachs were examined. Gastro-oesophageal ulcers were observed in 5.1%
of the stomachs, gastric erosion in 15.2%, and hyperkeratosis in 18.9%. Time of
slaughter was found to affect the prevalence of gastric lesions in the pig.
PMID- 9760400
TI - An outbreak of urticarial form of swine erysipelas in a medium-scale piggery in
Kiambu District, Kenya.
AB - This report concerns an outbreak that occurred during July/August 1997. Ten pigs
from a herd of 181 pigs in a medium-scale, semi-closed piggery in Kiambu
District, Kenya, contracted the clinical disease. The main clinical findings in
affected pigs included: fever (40.5-41.8 degrees C), prostration, inappetence,
dog-sitting posture, abortion, erythema and raised, firm to the touch and easily
palpated light pink to dark purple diamond-shaped to square/rectangular spots on
the skin around the belly and the back. Based on the pathognomonic skin lesions,
a clinical diagnosis of swine erysipelas was made. The diagnosis was confirmed by
the isolation of Erysipelothrix rhusiopathiae organisms from the blood and skin
biopsies taken from the affected pigs. Response to treatment with a combination
of procaine penicillin and dihydrostreptomycin at the dosage rate of 20,000 IU/kg
body weight (based on procaine penicillin) for 3 days was good and all the
affected pigs recovered fully. The farm was placed under quarantine to prevent
spread of the disease.
PMID- 9760401
TI - The zoonotic importance of Mycobacterium tuberculosis: transmission from human to
monkey.
AB - A case of zoonotic Mycobacterium tuberculosis infection in a marmoset (Callithrix
jacchus) is reported. Genomic typing of the relevant M. tuberculosis isolates
strongly suggests that the marmoset, which was kept as companion animal, acquired
the disease from an infected member in the household who had been treated for
pulmonary tuberculosis 8 years prior to this case.
PMID- 9760402
TI - Healthy animals: safe products: a healthier community.
PMID- 9760403
TI - [Toxicity study of sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino]
benzoyl] aminoacetate tetrahydrate (ONO-5046.Na) (1). Single-dose intravenous
toxicity studies in rats and dogs].
AB - Single-dose toxicity studies of sodium N-[2-[4-(2,2-dimethylpropionyloxy)
phenylsulfonylamino] benzoyl] aminoacetate tetrahydrate (ONO-5046.Na), a novel
neutrophil elastase inhibitor, were conducted in Sprague-Dawley (SD) rats and
beagle dogs. The rats of both sexes were administered ONO-5046.Na intravenously
at a single dose of 150, 300 or 450 mg/kg. The male dogs were also given ONO
5046.Na at a single dose of 75 or 150 mg/kg. In the rat study, hypoactivity,
bradypnea and paleness of limbs and pinna were observed at doses of 300 mg/kg and
above. In particular, one of six female rats in the 450 mg/kg group showed clonic
convulsion and died. In surviving animals, those signs disappeared within 3 hr
after administration. No effect on body weight gain was seen in either group.
Necropsy findings showed a slight foamy fluid in the bronchus, hemorrhage at the
right knee joint muscle, tendon and lung in a dead animal. In the dog study, no
effects on clinical signs, body weight, food consumption and blood biochemistry
were seen in any animals of the 75 and 150 mg/kg groups. It is concluded that the
approximate lethal doses are 450 mg/kg in rats and 150 mg/kg and above in dogs.
PMID- 9760405
TI - [Toxicity study of sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino]
benzoyl] aminoacetate tetrahydrate (ONO-5046.Na) (3). 4-week repeated dose
intravenous toxicity study in dogs with 4-week recovery test].
AB - 4-week repeated dose toxicity study with 4-week recovery test of sodium N-[2-[4
(2, 2-dimethylpropionyloxy) phenylsulfonylamino] benzoyl] aminoacetate
tetrahydrate (ONO-5046.Na), a novel neutrophil elastase inhibitor, was conducted
in beagle dogs. The dogs of both sexes were administered ONO-5046.Na
intravenously at a daily dose of 0 (vehicle control), 7.5, 15 or 30 mg/kg. In the
15 mg/kg female group and the 30 mg/kg male and female groups, transient
hypoactivity and ataxic gait were observed. It is considered that these symptoms
were attributed to the pharmacological effect of ONO-5046.Na. Also, in the 30
mg/kg male and female groups, erythrocyte, hematocrit and hemoglobin were
decreased. In the 30 mg/kg male group, lung weight was increased. However,
histopathological examination revealed there were no changes in any organs
including the lungs. There were no treatment-related changes in body weights,
food consumption, ophthalmology, occult blood in feces, urinalysis, blood
chemistry, electrocardiography, blood pressure, temperature, pulse rate, hepatic
and renal function or necropsy. These results indicate that the NOAEL of ONO
5046.Na in dogs in 15 mg/kg/day for both sexes in this study.
PMID- 9760404
TI - [Toxicity study of sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino]
benzoyl] aminoacetate tetrahydrate (ONO-5046.Na) (2). 4-week repeated dose
intravenous toxicity study in rats with 4-week recovery test].
AB - A 4-week repeated dose toxicity study with 4-week recovery test of sodium N-[2-[4
(2,2-dimethylpropionyloxy) phenylsulfonylamino] benzoyl] aminoacetate
tetrahydrate (ONO-5046.Na), a novel neutrophil elastase inhibitor, was conducted
in Sprague-Dawley (SD) rats. The rats of both sexes were administered ONO-5046.Na
intravenously at a daily dose of 0 (vehicle control and saline control), 18.75,
37.5, 75 or 150 mg/kg. ONO-5046.Na did not affect signs, body weight, food
consumption, ophthalmology, urinalysis, hematology, blood chemistry, organ
weights, necropsy or histopathology at any dose. These results indicate that the
NOAEL of (ONO-5046.Na in rats is 150 mg/kg/day for both sexes in this study.
PMID- 9760406
TI - [Toxicity study of sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino]
benzoyl] aminoacetate tetrahydrate (ONO-5046.Na) (4). 6-month repeated dose
intravenous toxicity study in rats with 1-month recovery test].
AB - A 6-month repeated dose toxicity study with 1-month recovery test of sodium N-[2
[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino] benzoyl] aminoacetate
tetrahydrate (ONO-5046.Na), a novel neutrophil elastase inhibitor, was conducted
in Sprague-Dawley (SD) rats. The rats of both sexes were administered ONO-5046.Na
intravenously at a daily dose of 0 (vehicle control), 18.75, 37.5 or 75 mg/kg.
ONO-5046.Na did not affect clinical signs, body weight, food consumption,
opthalmology, urinalysis, hematology, blood chemistry, organ weight, necropsy or
histopathology at any dose. These results indicate that the NOAEL of ONO-5046.Na
in rats is 75 mg/kg/day for both sexes in this study.
PMID- 9760408
TI - [Reproductive and developmental toxicity study of sodium N-[2-[4-(2,2
dimethylpropionyloxy) phenylsulfonylamino] benzoyl] aminoacetate tetrahydrate
(ONO-5046.Na (1). Fertility study in rats].
AB - Fertility study of sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino]
benzoyl] aminoacetate tetrahydrate (ONO-5046.Na), a novel neutrophil elastase
inhibitor, was conducted in Sprague-Dawley (SD) rats. ONO-5046.Na was
administered intravenously at doses of 18.75, 37.5 and 75 mg/kg/day to male rats
from 64 prior to mating, through the mating period and until necropsy, and to
female rats from 15 days prior to mating until Day 7 of gestation, in order to
examine its effects on fertility and reproductive performance of males and
females and the development of their fetuses. There were no changes attributable
to ONO-5046.Na in general signs, body weight, food consumption or autopsy
findings in males and females. No drug-related changes were observed in estrous
cycles, copulation and fertility indices in males and females. Pituitary weight
of dams was decreased in each of the ONO-5046.Na treated groups, but no
histopathological changes were observed in the pituitary. In the cesarean section
findings in dams, ONO-5046.Na had no effects on the number of corpola lutea, the
number of live fetuses, the implantation ratio, the resorbed and dead fetus
ratio, fetal or placental weight, or the incidences of external, skeletal or
visceral anomalies of the fetuses. From these results, it is considered that the
NOAEL of ONO-5046.Na is 75 mg/kg/day for general and reproductive toxicity in
males and females and for developmental toxicity in their fetuses.
PMID- 9760407
TI - [Toxicity study of sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino]
benzoyl] aminoacetate tetrahydrate (ONO-5046.Na) (5). 6-month repeated dose
intravenous toxicity study in dogs with 1-month recovery test].
AB - A 6-month repeated dose toxicity study with 1-month recovery test of sodium N-[2
[4-(2,2-dimethylpropionyloxy) phenylsulfonylamino] benzoyl] aminoacetate
tetrahydrate (ONO-5046.Na), a novel neutrophil elastase inhibitor, was conducted
in beagle dogs. The dogs of both sexes were administered ONO-5046.Na
intravenously at a daily dose of 0 (vehicle control), 7.5, 15 or 30 mg/kg. In the
15 mg/kg and above groups, transient ataxic gait was observed. It is considered
that this symptom could be attributed to the pharmacological effect of ONO
5046.Na. Macro- and microscopic hemorrhage at the injection site was observed in
the ONO-5046.Na treated groups. However, it is considered that these findings
could be attributed to the long-term repeated dosing procedure, and were not
toxic changes. There were no treatment-related changes in body weight, food
consumption, ophthalmology, urinalysis, hematology, blood chemistry,
electrocardiography and organ weights. These results indicate that the NOAEL of
ONO-5046.Na in dogs is 30 mg/kg/day for both sexes in this study.
PMID- 9760409
TI - [Reproductive and developmental toxicity study of sodium N-[2-[4-(2,2
dimethylpropionyloxy) phenylsulfonylamino] benzoyl] aminoacetate tetrahydrate
(ONO-5046.Na) (2). Study for effects on pre- and postnatal development in rats,
including maternal function].
AB - Prenatal and postnatal toxicity of sodium N-[2-[4-(2,2-dimethylpropionyloxy)
phenylsulfonylamino] benzoyl] aminoacetate tetrahydrate (ONO-5046.Na), a novel
inhibitor of human neutrophil elastase, was studied in Sprague-Dawley (SD) rats.
ONO-5046.Na was injected intravenously at doses of 0, 18.75, 37.5 and 75
mg/kg/day to pregnant rats from day 7 of pregnancy to day 20 after delivery. All
pregnant rats were allowed to deliver naturally for postnatal examination of
their offspring. No adverse effects on dams were observed in clinical signs, body
weight change, food consumption, pregnant, delivery or lactating performances.
ONO-5046.Na did not affect the postnatal development of offspring, including
birth index, survival index, physical and functional development, motor activity,
emotionality, learning ability and reproductive performance. From these results,
it is considered that the NOAEL of ONO-5046.Na is 75 mg/kg/day for dams and their
offspring.
PMID- 9760410
TI - [Reproductive and developmental toxicity study of sodium N-[2-[4-(2,2
dimethylpropionyloxy) phenylsulfonylamino] benzoyl] aminoacetate tetrahydrate
(ONO-5046.Na) (3). Teratogenicity study in rabbits].
AB - Teratogenicity of sodium N[2-[4-(2,2-dimethylpropionyloxy)
phenylsulfonylamino]benzoyl] aminoacetate tetrahydrate (ONO-5046.Na), a novel
inhibitor of human neutrophil elastase, was studied. ONO-5046.Na was injected
intravenously at doses of 0, 7.5, 15 and 30 mg/kg/day to pregnant Kbl: NZW
rabbits from day 6 to day 18 of pregnancy. All female rabbits were sacrificed on
day 29 of pregnancy and their fetuses were examined. There were no clinical signs
or death attributable to ONO-5046.Na. One dam in the control group and 3 dams in
the 30 mg/kg/day group aborted. Body weight gain in the 15 and 20 mg/kg/day
groups and food intake in the 30 mg/kg/day group were decreased during the
administration period. These changes had recovered by the end of the study.
Kidney weight was increased in the 30 mg/kg/day group. There were no effects of
ONO-5046.Na in necropsy findings at cesarean section in dams at any dose levels.
Developmental toxicity of ONO-5046.Na was not found at any dose levels. From
these results, it is considered that the NOAEL of ONO-5046.Na is 7.5 mg/kg/day
for pregnant animals and 30 mg/kg/day for fetuses.
PMID- 9760411
TI - [Effects of mesalazine on liver carcinogenesis in medium-term bioassay using
rats].
AB - A two stage carcinogenesis promotion test using phenobarbital (PB) as a positive
control was performed on mesalazine in rats (F344,male). Pathological and
immunohistological examinations were performed to examine the cell damage and
proliferation in the liver and kidneys. As the initiation treatment, groups 1,2,3
and 5 were administered 300 mg/kg diethylnitrosamine (DEN)dissolved in 0.9%
physiological saline, and group 4 was administered 5 ml/kg 0.9% physiological
saline once intraperitoneally. Then group 1 was orally administered a water
solution (5 ml/kg) containing 0.5% CMC-Na, and groups 2,3 and 4 similar water
solution but containing 150, 300 and 300 mg/kg mesalazine, respectively. Group 5
was administered 0.05% PB mixed in feed from weeks 2 to 8. Partial (2/3)
hepatectomy was performed in all 5 groups at week 3 after DEN administration. NO
clear differences between the groups were observed in general conditions, body
weight or amount of food consumption. The number or area-size of hepatic GST-P
positive altered cell foci revealed no significant differences between groups 1,2
and 3, but a significant increase in number and area-size was observed in group
5. No GST-P positive cell foci were detected in group 4. The number of altered
cell foci (H.E. staining) in the DENgroups administered mesalazine was the same
as that in group 1. Thus, mesalazine did not promote hepatocarcinogenesis in the
present experimental system. Statistically insignificant appearances of
basophilic and acidophilic changes were observed in the renal tubular epithelium
and mineral deposits in the renal papillary region and cortical margin region.
The PCNA labeling rate was significantly lower in group 4, corresponding with the
histological finding showing no proliferation of the renal tubular epithelium.
Judging from the above test results, mesalazine was likely to show neither a
promotion effect on the initiation induced by DEN nor cell proliferative activity
on the kidneys by administration for this experimental period.
PMID- 9760412
TI - Skin sensitization and photosensitization studies of hydrophobically modified
hydroxypropyl methylcellulose in guinea pigs.
AB - Skin sensitization and photosensitization tests of hydrophobically modified
hydroxypropyl methylcellulose (HM-HPMC), a new cellulose derivative used as a
thickener for topical pharmaceuticals, were conducted using guinea pigs. An
aqueous dispersion of HM-HPMC (3 w/v %) was applied in the tests. Skin reaction
was not observed in any animal in the HM-HPMC-treated group or control group. In
the photosensitization test, no skin reaction was found in any animal in the test
preparation group or the control group. It was concluded that HM-HPMC dispersion
does not exhibit skin sensitizing or photosensitizing activity under the
condition of this test.
PMID- 9760414
TI - Trace elements and apoptosis.
AB - It is known that apoptosis is considered to be responsible for selective deletion
of cells during embryogenesis, the homeostasis of cell populations in
continuously renewing tissues (i.e., serving as a counterbalance to mitosis), and
tissue involution in response to chemical or physical stimuli. There are many
publications on these questions. On the other hand, the intracellular processes
that contribute to apoptosis are incompletely understood. Therefore, the role of
apoptosis in the intracellular accumulation and outflow of minerals is of
considerable importance in light of both their essential functions and toxic
effects.
PMID- 9760413
TI - Thirteen-week repeated oral dose toxicity study of ecabapide, a gastroprokinetic
drug, in dogs and rats.
AB - Thirteen-week oral repeated dose toxicity of ecabapide, a gastroprokinetic drug,
was investigated in dogs at dosage levels of 50, 175 or 600 mg/kg, and in rats at
dosage levels of 25, 100, 400 or 1600 mg/kg. In dogs, vomiting, aqueous
salivation, body weight gain inhibition, and hemolytic anemia, together with an
increase in Heinz body formation, were observed at 175 and/or 600 mg/kg.
Histological examination revealed enhanced hemosiderin deposition in the liver
and spleen, retention of erythrocytes in the splenic sinus and enhanced
erythropoiesis in bone marrow at 175 and/or 600 mg/kg. In the rat study, although
increases in serum total protein, albumin and calcium, as well as increased liver
and kidney weights, were observed at 400 and/or 1600 mg/kg, no obvious
morphological changes were seen. The hemolytic anemia and an increased Heinz body
formation were not observed in rats, indicating a species difference. On the
basis of these results, the non-toxic dose of ecabapide was considered to be 50
mg/kg in dogs and 100 mg/kg in rats.
PMID- 9760415
TI - Organic and inorganic selenium supplementation to lactating mothers increase the
blood and milk Se concentrations and Se intake by breast-fed infants.
AB - The aim of this study was to determine the effect of selenium (Se)
supplementation to lactating women on Se concentrations and glutathione
peroxidase (GSH-Px) activities in blood components of mothers and breast-fed
infants and on milk Se levels and Se intake by breast-fed infants. Lactating
mothers were supplied for 3 months with 200 micrograms Se/day in the form of
yeast-Se (Y-Se) and sodium selenite. Initial blood and plasma Se levels of all
women (n = 67) were 76.6 and 53.2 micrograms/L, respectively. After 3 months Se
concentrations both in whole blood and in plasma from mothers and infants were
significantly higher than the initial values. Y-Se exerts a stronger effects than
selenite on blood and plasma Se levels. Initial milk Se concentration was 8.9
micrograms/L and after 1 month in both groups in reached a plateau at 14-16
micrograms/L. This resulted in an increase of Se intake in breast-fed infants
from 6.1 to a plateau of 11-13 micrograms Se/day. GSH-Px activities in plasma and
red cells of Y-Se group increased significantly and reached a plateau after 1 and
2 months, respectively, while in the selenite group the enzyme activities
increased steadily throughout the entire period of the study. Selenite exerts a
stronger effect on GSH-Px both in maternal and in infant blood components as
compared with Y-Se. In milk the GSH-Px activity in the Y-Se group did not change
during the study, while in the selenite group after 3 months it increased almost
2-fold compared to the initial value. In conclusion, this study shows that
organic Se causes higher Se deposition than did the inorganic form.
PMID- 9760416
TI - Effects of thiamin and methionine administration in preventing cadmium-induced
biochemical alterations and metal concentration in male rats.
AB - Thiamin or methionine supplementation was equally and moderately effective in
preventing the accumulation of cadmium in soft organs and alterations in a few
selected biochemical indices during concomitant administration. Adequate intake
of sulfur amino acid following methionine supplementation might increase the
bioavailability of glutathione, facilitating the prevention of the binding of
cadmium to different compartments and consequently reversing cadmium-induced
biochemical disorders. In the case of thiamine the possibility of formation of a
readily excretable complex between cadmium and thiamine or an increase in the
body's resistance to cadmium might be the beneficial factor.
PMID- 9760417
TI - Selenium, zinc and copper in plasma of patients with type 1 diabetes mellitus in
different metabolic control states.
AB - The Studies of selenium (Se), zinc (Zn) and copper (Cu) levels in diabetic
patients have led to contradictory findings as the possible relationship between
the degree of diabetic control and the changes in mineral contents. In the
present study the plasma Cu, Se, and Zn contents of diabetic patients and healthy
people were measured and the relationship between these contents and diabetic
metabolic control, as determined by glycosylated hemoglobin (HbA1c), was studied.
The mean plasma Se content in diabetic patients was significantly lower than in
controls (p < 0.01) and a negative correlation between the plasma contents of Se
and HbA1c was found. No statistically significant differences in plasma Zn
contents, either between patients with type 1 diabetes mellitus and control, were
found. A statistically significant sex difference in plasma Cu contents was
observed in the control population. In females, statistically significant
differences were found in plasma Cu contents between the control subjects and the
diabetic patients with medium or poor metabolic control, as well as between
diabetic patients with good and poor metabolic control. In males, the only
statistically significant differences were between the control subjects and
diabetic patients with poor metabolic control. The correlation between plasma
contents of Cu and HbA1c is not significant.
PMID- 9760418
TI - Study of the antioxidant effect of several selenium and sulphur compounds.
AB - Four selenium derivatives (sodium selenate, sodium selenite, selenourea and
selenomethionine) and the sulphur analogues (sodium sulfate, sodium sulfite,
thiourea and methionine), together with urea, were examined by means of
polarography to study their reactivity towards superoxide ion O2. In order that
experimental results could be applied to physiological conditions and to control
the electroreduction of oxygen, most reactions were carried out in model systems
(in the presence and in the absence of triphenyl phosphine oxide and at
increasing pH) which are briefly described and discussed. Sodium sulfite and
thiourea react with molecular oxygen; selenourea originates an anodic wave,
although under other pH conditions. Other compounds (selenate, selenite, seleno
methionine and methionine) display an interesting antioxidant capacity because
they catalyse the disproportion of the superoxide ion, as documented by the
increase in the limiting current. Methionine appears to be particularly efficient
in this respect, since it retains its catalytic ability in a poorly protic
environment. Experimental results support the view that exogenous compounds,
administered for particular purposes, can display unanticipated, and sometimes
positive, side effects.
PMID- 9760420
TI - Elements in autopsy liver tissue samples from Greenlandic Inuit and Danes. I.
Sulphur, chlorine, potassium and bromine measured by X-ray fluorescence
spectrometry.
AB - The purpose of this study was to measure the content of the elements Sulphur (S),
Chlorine (C1), Potassium (K) and Bromine (Br) in normal liver tissue samples from
Greenlandic Inuit using X-ray fluorescence spectrometry, and compare the results
with those obtained in normal liver tissue samples from Danes. Liver tissue
sample were obtained at autopsy from 50 Greenlandic Inuit (27 men, 23 women) with
a median age of 61 years (range 20-83) and from 74 Danes (44 men, 30 women) with
a median age of 52 years (range 15-87). In Inuit, the content of elements given
as median and (5-95 percentile) was: sulphur, 108.07 mmol/kg dry liver (86.78 -
169.44); chlorine, 92.16 mmol/kg dry liver (45.39-128.42); potassium, 181.66
mmol/kg dry liver (146.41-236.35); bromine, 0.0901 mmol/kg dry liver (0.0563
0.1589). In Danes, the corresponding values were: sulphur, 147.58 mmol/kg dry
liver (70.41-236.81); chlorine, 96.95 mmol/kg dry liver (54.01-162.52);
potassium, 198.40 mmol/kg dry liver (150.68-256.37); bromine, 0.1101 mmol/kg dry
liver (0.0701 - 0.4203). None of the elements displayed any significant gender
difference, neither in Inuit nor in Danes. Inuit had a lower liver content of
sulphur (p < 0.0001), potassium (p < 0.008) and bromine (p < 0.002) as compared
with Danes.
PMID- 9760419
TI - Chromium determination in osteoblast-like cell culture medium by catalytic
cathodic stripping voltammetry with a mercury microelectrode.
AB - A catalytic cathodic stripping voltammetric procedure for the determination of
total chromium in osteoblast-like cell culture medium using a mercury film
microelectrode (MFM) was optimised. The method is based on the pre-concentration
of the Cr(III)-diethylenetriaminepentaacetic acid (DTPA) complex by adsorption at
the potential of-1.00 V (vs. Ag/AgC1) in the presence of 10 x 10(-3) mol/L DTPA,
0.70 mol/L sodium nitrate, 0.04 mol/L sodium acetate and 1.0 x 10(-3) mol/L
potassium permanganate at pH 5.9-6.0. The limit of detection obtained for a 40 s
collection time was 2.80 x 10(-10) mol/L of chromium. The results achieved by
stripping voltammetry using the MFM were compared to those obtained by atomic
absorption spectrometry (AAS) to ensure the reliability of the electrochemical
method. This procedure proved to be an alternative to AAS and valuable in
biocompatibility studies performed in vitro using osteoblast-like cells.
PMID- 9760421
TI - Determination of nickel in saliva by electrothermal atomic absorption
spectrometry using various chemical modifiers with Zeeman-effect background
correction.
AB - The profile of nickel signal using electrothermal atomic absorption spectrometry
with deuterium and Zeeman-effect background correction is presented. The Zeeman
effect system of background correction offered definitive advantages and
therefore was used for the determination of nickel in saliva in the presence of
various isomorphous metals. The highest nickel absorbance values corresponded at
200, 300, 300, 300, 600, and 200 ng of Tb, Mg, Sm, Lu, Tm, and Pd, respectively.
On the other hand, the addition of Eu, Er, and Ho decreased the nickel signal.
The presence on each modifier alone does not eliminate the matrix interference.
However, the use of 200 ng of Pd in conjuction with 300 ng of Lu has a higher
sensitivity, offers an advantage against interference from the background of
saliva matrix and produces good recoveries (98 to 102% from unspiked and spiked
saliva samples). The limit of detection was 0.11 micrograms/L for a
characteristic mass of 16.6 pg of nickel using Pd-Lu as modifier. The within
batch precision varied between 0.8 and 1.5% relative standard deviations. The
analysis of thirty samples of whole saliva gave an average of 0.81 +/- 0.30 of
micrograms/L of Ni (range from 0.5 to 2.0 micrograms/L of Ni). The agreement
between the observed and certified values obtained from a Seronorm Blood Serum
Standard Reference Material was good.
PMID- 9760422
TI - [Biology and growth velocity of tumors of the globus jugulotympanicum and glomus
caroticum].
AB - BACKGROUND: Paragangliomas (glomus tumors) of the head and neck are rare tumors,
arising from the paragangliomatous tissue either of the carotid region or the
jugular or the tympanic region. This study was conducted to investigate the
possible differences in the tumor biology of these lesions depending on their
site of origin. METHODS: Nineteen specimens (10 jugulotympanic and 9 carotid
glomus tumors) were investigated by quantitative DNA measurements and
immunohistochemical assessment of proliferation markers (PCNA, Ki67), oncogenes
(p53, nm23), different cell surface antigenes (CD44 4/5 and 6, CD54, CD106), and
bcl 2 as a marker for apoptosis. RESULTS: Depending on the location of the tumors
these measurements revealed significant differences in tumor biology with higher
proliferation scores and a higher number of aneuploid tumors in those of the
carotid region, suggesting a more aggressive behavior compared to those of the
jugulotympanic region. CONCLUSIONS: The results also indicate a difference
between the two groups in the risk of developing metastases or recurrent disease.
They generally help to enhance our understanding of the biology of paragangliomas
of the head and neck.
PMID- 9760423
TI - [Jugulotympanic paraganglioma: therapy concepts under development].
AB - BACKGROUND: The operative treatment and radiation therapy of jugulotympanic
paragangliomas (JTP) are still a matter of controversial discussion. In spite of
various improvements during the last 50 years, selecting the appropriate
treatment modality (surgery, radiation, or observation) is still a challenge.
PATIENTS: During a 16-year period, 44 patients with 45 JTP (10 at level A/B and
35 at level C/D according to Fisch) were seen at the ENT-department in Fulda.
Forty-one cases were treated surgically. RESULTS: Complete resection was possible
for level A/B in 100% of the patients (n = 10). Residual tumor was demonstrated
for level C in 23% of the patients (5/22) and for level D in 40% (4/10) with a
median follow-up time of 69 months. In two cases residual tumor was treated by
radiation. Six patients with residual paraganglioma tissue were maintained under
observation without any evidence of tumor progression (median follow-up time 39
months). We report one death after the attempt to resect a large residual
paraganglioma that had already caused brain stem compression. A sufficient
duraplasty could not be achieved following radiation therapy. CONCLUSIONS:
Complete tumor resection of jugulotympanic paragangliomas of levels A and B is
often possible without injury to the cranial nerves. Extensive tumors present
difficulties in complete tumor resection and increase the risk of cranial nerve
injuries. Advanced paragangliomas therefore require an individualized therapeutic
regime including surgery, radiation therapy, and observation of tumor growth.
PMID- 9760424
TI - [Chronic mycoses of the paranasal sinuses--value of endonasal paranasal sinus
surgery].
AB - BACKGROUND: Many host factors even in immunocompetent patients may have an
influence on development of a fungal diseases within the paranasal sinuses.
Fungal sinusitis can occur in an acute form or more often to a chronic type of
the disease. These mainly relatively asymptomatic chronic forms and further
divided into a chronic noninvasive, chronic allergic, and chronic invasive
disease. Endonasal microsurgery has significantly changed the management of
chronic fungal sinusitis and allows adequate removal of pathologic tissue even in
advanced situations. The aim of this study was to analyze the efficacy of
endonasal surgery in chronic fungal sinusitis. MATERIAL AND METHODS: In a
retrospective study we assessed a group of 40 patients who had endonasal surgery
for chronic fungal sinusitis. Patient records, CT and MRI scans, microbiology and
histology as well as the postoperative clinical follow-up including endoscopic
photo documentation were evaluated over a period of 5 years. All patients
underwent endonasal surgery using endoscopic techniques. The microscopic was of
additional help in a few cases with extended disease and multiple dehiscences of
the skull base. RESULTS: Twenty-four patients had a chronic noninvasive of fungal
sinusitis and 16 patients had a chronic invasive form. All these patients
underwent endonasal surgery without external incision. The fungal disease was
erradicated in 39 cases, and revision surgery was required in only one case in
which involvement of the contralateral side was not initially detected. in two
cases scar tissue in the middle meatus was later excised but without evidence of
residual fungal disease. Only in 6 cases was antifungal chemotherapy required,
where the disease had spread into surrounding tissue or the patient had severe
symptoms. CONCLUSIONS: Endonasal microsurgical techniques are today the
appropriate approach for managing chronic fungal sinus disease even in severe
cases with radiologic evidence of expansion or invasion of surrounding tissue.
Additional antifungal chemotherapy is only rarely indicated, specifically when
the fungal disease invades surrounding tissue.
PMID- 9760425
TI - [Paranasal sinuses: only one of nature's games?].
AB - BACKGROUND: Many theories exist concerning the function of paranasal sinuses, but
it is rather difficult to definitively name the right one. Despite the fact that
many of them have been proved to be wrong, they are still used. THEORIES: Galen
postulated 2000 years ago that they were "porous bones", which helped with weight
reduction. Like Galen's theory, most of the others have been refuted as well. A
list of these refuted theories covers a range of postulated functions including a
relative warming or moistening of the breath, protection against high pressure in
the nasal region when sneezing, paranasal sinuses as a place of efficient mucus
production, or an aid for smelling, similar to the ethmoidal cells of the
porcupine. Others include an isolated function for protection against cold
climates and an aid for formulating sound by acting as a resonance chambers.
CONCLUSIONS: Two theories still remain. One says that the paranasal sinuses are
only the result of the evolutionary processes that have taken place in the skull
during human development. The other theory explain that the form of the paranasal
sinuses exists through the influence of the forces created during the act of
chewing. Small cavities appear as a result of the minimal energy created, and
these cavities can be found in the form of paranasal sinuses.
PMID- 9760426
TI - [Otogenic brain abscess].
AB - BACKGROUND: Otogenic complications are rare but typical following acute or
chronic ear infections like mastoiditis and cholesteatoma. A life-threatening
sequela is the otogenic brain abscess located in the temporal lobe or cerebellum.
PATIENTS: At the ENT Department of the Medical University of Hannover/Germany we
treated 8 patients suffering from otogenic brain abscesses in the temporal lobe
during the last three years. The average age of the 6 male and 2 female patients
was 48 years. In 5 patients the abscess developed due to a cholesteatoma with
superinfection. Three cases showed acute mastoiditis. All patients were operated
using an otosurgical retroauricular approach, in five cases a classical radical
mastoidectomy was performed. In two cases the abscess was reached via mastoidal
approach and was subsequently drained. In two other cases the abscess was drained
some days later by neurosurgical approach due to increased neurological symptoms.
The other patients were treated with high-dosed antibiotics under regular
clinical and radiological control. RESULTS: In 7 cases complete regression of the
abscess was achieved. Five patients were discharged without further otological or
central-nervous problems. One female patient developed severe meningitis with
generalized thrombosis of the central blood sinus system and died in central
circulatory failure. Two other patients developed a moderate psychopathologic
syndrome and were admitted to rehabilitation institutions. CONCLUSIONS: The
analysis of our patients shows that otogenic brain abscesses should be regarded
especially as a severe complication of the untreated cholesteatoma. It is
important to use modern imaging modalities like computer tomography or MRI for
early detection of the intracerebral lesion and to perform an early otosurgical
intervention. Under antibiotics and CT control, healing of this severe
complication can be achieved in most cases. However, the danger of acute and
chronic ear diseases has to be kept in mind in all medical disciplines.
PMID- 9760427
TI - [Long-term outcome after reconstruction of the cranial base with ionomer cement].
AB - BACKGROUND: Congenital, posttraumatic, inflammatory or tumours skull base lesions
with CSF leakage require reconstruction to mechanically stabilize the CNS and to
securely seal the CSF space. PATIENTS AND METHODS: Ionomeric cement was used from
1988 until 1994 in 44 patients for skull base reconstruction at the Department of
Otolaryngology-Head and Neck Surgery, University of Wurzburg. Thirty-five
patients were reexamined. The longest follow-up time was 8 years. The program for
the present follow-up study comprised a general ENT and neurological examination
as well as CT scans of the skull base, MRI tomography of the CNS, and the
determination of the aluminium plasma concentration. RESULTS: None of the
patients reexamined presented with complaints. Neurological examinations and MRI
tomography in all patients did not reveal any pathological finding related to
ionomeric cement application. Aluminium plasma concentrations in patients who
received ionomeric cement implantations were not significantly elevated when
compared to controls. General ENT examinations and CT scans in thirty-two
patients demonstrated regular postoperative findings. The cement at the anterior
skull base was not covered completely by mucosa in three patients. In one these
cases, CT scans revealed dislocation of the ionomeric cement so that revision
surgery was performed for removal. None of the patients to date presented with a
CSF leak. CONCLUSION: Long-term results of the present study show that ionomeric
cement is a suitable material for closure of osseous skull base lesions to
permanently seal the CSF space. These results, however, can only be obtained when
handling and application of the material is adequate. Unfortunately, the
production of ionomeric cement has been stopped since 1995 following four cases
of aluminium encephalopathy reported in the literature.
PMID- 9760430
TI - [Occupational medicine issues in Poland].
PMID- 9760428
TI - [Reconstruction of the forehead region with tabula externa of the skull].
AB - BACKGROUND: Calvarial bone graft is often used in reconstructive cranio-facial
surgery. As most common three different forms can be distinguished: outer-table
bone, full thickness grafts and composite flaps (bone with a periostal or
muscular pedicle). PATIENT AND METHOD: An extensive fibrous dysplasia of the
frontal region was removed in a 26 years old patient. Reconstruction was carried
out with alloplastic material achieving a good esthetic result. Recurrent seroma
and occurrence of a fistula demanded removal of the alloplastic material and en
bloc reconstruction of the forehead region was accomplished with a parietal outer
table graft. Within a follow-up time of one year a good esthetic and stable
reconstruction has been achieved. CONCLUSION: Split-thickness calvarial bone is
still a versatile graft in reconstruction of the forehead region. Although a low
rate of side effects in harvesting calvarial bone grafts are in general expected,
one has to be aware of dural lesions occuring in the donor site during
craniotomy.
PMID- 9760429
TI - [Interesting case no. 15. Double median neck cyst].
PMID- 9760431
TI - [Occupational lead poisoning in Poland].
AB - During the years 1970-1996, 8,414 cases (8,176 among men and 238 among women) of
lead poisoning, recognised as occupational disease, were registered with the peak
in 1972-1976 (500-800 cases per year). An in-depth analysis of 7,893 (men)
reported in the period between 1970 and 1992 revealed that repeated poisonings in
the same person were observed quite frequently. Among 4,556 men poisoned by lead
during the period under study, in every third men the disease was diagnosed at
least twice. Almost half of men with occupational lead poisoning received the
occupational disease certification after the exposure lasting less than five
years. The majority of persons poisoned by lead (64.3%) were employed in plants
located in the Katowice voivodship. More than half of men with occupational lead
poisoning (54.1%) was exposed to maximum concentrations of lead, exceeding MAC
values by two hundred times. A diminishing number of occupational lead poisoning
observed during the 1990s does not reflect a real-level of occupational exposure.
The majority of cases reported apply to large plants or industrial complexes
where the prevention of poisonings is rather well organised. But dispersed small
production and service enterprises, where acute cases of poisoning may lead to
irreversible organic changes create a great problem. One of the prerequisites for
effective prevention of occupational lead poisoning is to identify and to make a
complete inventory of workplaces where lead occurs, as well as to identify
workposts hazardous to worker's health, and to monitor lead concentrations in the
air.
PMID- 9760432
TI - [Prevention of vibration syndrome in selected occupational groups in the
metallurgy industry].
AB - Medical examinations were carried out in a group of 297 men exposed to hand-arm
vibration in the metallurgical industry. The group consisted of 93 rammers, 77
grinders and 127 chippers. The level of vibration at workposts was also measured.
The average occupational exposures exposed in years and total hours were as
follows: in the group of rammers - 14.5 yrs and 19,954 h; grinders - 15.2 yrs and
10,131 h; and chippers - 8.8 yrs and 5,444 h. The vibration-dose limit was
exceeded by 5.0, 0.96 and 1.1 times, respectively. Raynaud's phenomenon was found
significantly more frequent in chippers than in rammers or grinders. Medical
examinations showed the highest health risk among chippers and the lowest among
rammers. No correlation was found between intensity of mechanical vibration at
the workplace and the biological response in groups examined. The results of the
examinations provided evidence that different groups of workers require different
preventive programmes.
PMID- 9760433
TI - [Risk factors for premature birth. I. Analysis of selected factors in a group of
non-working women].
AB - Selected risk factors responsible for premature birth in a group of women non
employed professionally were discussed. The analysis included demographic (age,
education, marital status, maternal body weight, the number of previous
pregnancies, as well as spontaneous and artificial abortions reported in
interview), social (smoking, exposure to tobacco smoke, family economic status,
standard of living conditions, and facilities used in running the household), and
medical (maternal health status before and during pregnancy, and perinatal care)
factors, as well as work load at home. The authors found low maternal body
weight, genital bleeding during pregnancy and work overload at home to be the
most significant risk factors.
PMID- 9760434
TI - [Evaluation of binocular vision in persons employed at high work posts].
AB - The study covered 250 workers, aged 20-63 years, employed at workposts over 3
meters high. We analysed visual acuity, refraction, anterior segment, eye ground,
visual field, colour vision and binocular vision. The study revealed that 20% of
persons examined lack the stereoscopic vision ability. In conclusion it is
suggested to use combined methods in order to evaluate binocular vision and
certify ability to work at high workposts.
PMID- 9760435
TI - [Detection of antibodies to Borrelia burgdorferi among forestry workers in North
Eastern Poland].
AB - The purpose of the study was to assess the incidence of Borrelia burgdorferi
antibodies and clinical forms of Lyme borreliosis among forestry workers in north
eastern Poland. The group studied consisted of 1,466 persons (297 women and 1,169
men), aged 20-70 years. In 439 (23.81%) persons the presence of B. burgdorferi
antibodies was detected in serum, in 271 (18.49%) persons active Lyme borreliosis
was diagnosed and 78 (5.32%) persons were carriers of B. burgdorferi antibodies.
Arthritis (43.84%) and neuroborreliosis (32.95%) were found to be the most common
forms of borreliosis.
PMID- 9760436
TI - [Exposure to electromagnetic fields with frequencies of 50 Hz and changes in the
circulatory system in workers at electrical power stations].
AB - Bearing in mind a great diffusion of electromagnetic fields (EMF) with power-line
frequency (in Poland-50 Hz) both in the occupational and communal environments,
it is not surprising that possible health effects related to this exposure evoke
much interest. Electromagnetic fields may affect the circulatory and nervous
systems because of theoretical probability that electric impulses, generated by
external electric and magnetic fields, may disturb their functions. For this
reason we have decided to evaluate the functioning of the circulatory system in
persons occupationally exposed to power-line frequency electromagnetic fields by
employing the most up-to-date methods facilitating the in-depth diagnosis of the
circulatory system and neurovegetative mechanisms. The work presented focused on
the evaluation of electrocardiographic changes. The study covered 63 workers of
the transforming and distributing stations, aged 22-67 years (median 39 +/- 10),
employed under exposure for 2-43 years (median 15 +/- 10). The control group
consisted of 42 workers of radio link stations, aged 23-65 years (median 30 +/-
14), employed in the similar system but not exposed to EMF, with employment
duration of 1-42 years (median 13 +/- 4). All persons were subject to general
medical examinations, resting ECG, and 24 h Holter monitoring. In addition, the
level of exposure in individual workplaces was estimated following the
measurements of the intensity of electric and magnetic fields. In workers of
electromagnetic stations an increased risk for electrocardiographic disturbances
was revealed. Under conditions of exposure to electric fields, observed in
stations where workers were employed, the risk was increased by 10%.
PMID- 9760437
TI - [Evaluation of exposure to halothane and ethyl alcohol among technicians
responsible for maintenance of anesthesia equipment].
AB - The authors discuss the measurements of exposure to halotane and ethyl alcohol
among technicians responsible for maintenance of anaesthesiological instruments
that occurs at various stages of maintenance work and in an operating room.
PMID- 9760438
TI - [Absorption and dispersion of ultraviolet radiation in human skin].
AB - The study was carried out in a group composed of 48 men. The linear coefficient
and linear coefficient of dispersion of ultraviolet radiation (UVR) in the skin
was measured for different wavelengths. The mean values were determined for four
types of the skin in both ultraviolet A (UVA) and ultraviolet B (UVB) ranges from
280 to 400 nm. The skin ability to absorb UVR decreases rapidly with decreasing
wavelength. At wavelength of 280 nm, the coefficient of absorption changed within
the range from 105 cm-1 (skin type II) to 160 cm-1 (skin type V), however, at
wavelength of 400 nm it accounted only for 20 cm-1. A reciprocal relationship for
scattering was found. The coefficient of dispersion changed within the range from
3.5 cm-1 at wavelength of 280 nm to 12 cm-1 at wavelength of 400nm. The mechanism
based on absorption predominated at a shorter wave range (UVB), while at a longer
range (UVA) the scattering mechanism was more efficient.
PMID- 9760439
TI - [Limitations in using international occupational disease statistics for
comparative analysis].
AB - The comparability of international statistical data on the incidence of
occupational disease is discussed. The examples of some countries served to
present the reasons why the relevant data available in publications cannot be
often used as a frame of reference to comparative studies. The problem results
mainly from different definitions of the term "occupational disease" as they
frequently include in their context also these pathologies which are numbered
among work-related diseases. In addition, the authors highlighted the steps
undertaken by international organizations (World Health Organization,
International Labour Organization, and European Union) to unify both the
diagnostic procedures and the system of collecting and publishing of statistical
data on occupational diseases.
PMID- 9760440
TI - Progress in nephrotoxicology: from in vivo screening test to molecular
mechanisms.
PMID- 9760441
TI - Metallothionein transgenic and knock-out mouse models in the study of cadmium
toxicity.
AB - The role of MT in Cd toxicology has become clearer by the use of MT-I transgenic
and MT-I and -II knock-out animals. We have shown that: (1) MT-transgenic and
null mice have altered tissue MT protein levels; (2) MT-transgenic and -null mice
appear to be normal in other detoxifying systems examined, except for slight
alterations in tissue Zn concentration; (3) MT does not appear to inhibit Cd
absorption from the gastrointestinal tract, nor affect Cd tissue distribution;
(4) MT reduces the elimination of Cd from liver; (5) MT protects against acute
inorganic Cd-induced lethality and hepatotoxicity, and the mechanism of the
protection appears to be due to its ability to sequester Cd in the cytosol, thus
reducing the amount of Cd in critical organelles; (6) MT modulates Cd-induced
expression of protooncogene(c-jin) and tumor suppress genes (p53) in mouse liver;
(7) MT does not protect against CdMT-induced acute renal injury, and Zn-induced
protection against CdMT-induced acute nephrotoxicity does not appear to be
mediated through MT; (8) Chronic Cd administration produces renal injury inb MT
null mice, indicating that Cd-induced nephrotoxicity is not necessarily mediated
through the CdMT complex; (9) MT protects against chronic CdC12 nephropathy,
suggesting that intracellular MT is an important adaptive mechanism decreasing
CdC12 nephrotoxicity, and that a single injection of CdMT may not be a good model
to study chronic Cd nephropathy; (10) genetic background of mouse strains, rather
than constitutive MT levels, is a more important determinant for Cd-induced acute
testicular injury. In addition to Cd detoxication, MT-transgenic and MT-null mice
are also good models to determine other functions of MT. MT plays important roles
in maintaining Zn homeostasis and protection against Zn toxicity. Knock-out of
the MT gene also renders animals/cells more vulnerable to oxidative stress and
DNA alkylating agent-induced toxicity. Therefore, the MT-transgenic and knock-out
mouse models provide complementary approaches to those used previously, and have
greatly increased our understanding of the role of MT in Cd toxicology, as well
as other biological functions of MT.
PMID- 9760442
TI - Medium-term bioassays as alternative carcinogenicity test.
AB - A medium-term liver bioassay system for rapid detection of carcinogenic agents
using male F344 rats has been developed, in order to bridge the gap between long
term carcinogenicity tests and short-term screening assays. The system is
fundamentally based on the two-stage hypothesis of carcinogenesis: initiation
with diethylnitrosamine (200 mg/kg bw, i.p.) is followed by test chemical
administration during the second, in combination with 2/3 partial hepatectomy. It
requires only 8 weeks for animal experimental treatment and a further few weeks
for quantitative analysis of immunohistochemically-demonstrated glutathione S
transferase placental form positive hepatic foci. A total of 291
chemicals/substances have already been analyzed in this laboratory and the
efficacy of the system for hepatocarcinogens has thereby been well established.
This bioassay is particularly useful for dose-response and chemical mixture
studies, usually requiring large-scale experiments and also for evaluation of
chemopreventive agents. Another bioassay, a medium-term multiorgan bioassay
system, using 5 different chemical carcinogens, diethylnitrosamine (DEN), N
methylnitrosourea (MNU), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), 1,2
dimethylhydrazine (DMH) and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN), has
also been established for rapid detection of not only hepatocarcinogens, but also
other organ-target carcinogens. Rats were initially treated with a single i.p.
administration of 100 mg/kg DEN, 4 i.p. administrations of 20 mg/kg MNU, 4 s.c.
doses of 40 mg/kg DMH for 2 weeks and then 0.1% DHPN for 2 weeks. Test chemicals
are administered after the carcinogens exposure. Animals were sacrificed at the
end of week 36, and major organs were examined histologically. Carcinogenic
activities of test chemicals were compared between the test chemical treated
group and carcinogen exposures group (control group). It is increasingly becoming
regarded that these bioassays are useful methods and are appropriate alternative
tests systems for carcinogenicity risk assessment. Therefore, 'the International
Conference on Harmonization (ICH) of Technical Requirements for the Registration
of Pharmaceuticals for Human Use' has proposed that these two bioassays can be
used as "additional tests for carcinogenic activity in vivo."
PMID- 9760443
TI - The achievement and prospect of toxicology in China.
PMID- 9760444
TI - Regulation of DNA damage inducible rhp51+ gene, a rec A homolog from
Schizosaccharomyces pombe.
PMID- 9760445
TI - Neuromuscular toxicity of anticholinesterase agents.
PMID- 9760446
TI - Lead poisoning in waterfowl.
PMID- 9760447
TI - Cycad poisoning in cattle in Japan--studies on spontaneous and experimental
cases.
PMID- 9760448
TI - Pharmacogenetics of CYP2C subfamily in a Japanese population.
PMID- 9760449
TI - Aflatoxin B1 oxidation by human cytochrome P450s.
PMID- 9760450
TI - UDPGT cDNA expression and UDPGT1 in human liver.
AB - Following expression of UDPGTh1 and UDPGTh2 in Cos-1 cells, each isoform
metabolized three types of dihydroxy- or trihydroxy-substituted ring structures,
including the 3,4-catechol estrogen (4-hydroxyestrone), estriol and 17
epiestriol, and hyodeoxycholic acid (HDCA), but the UDPGTh2 isozyme was 100-fold
more efficient than UDPGTh1. UDPGTh1 and UDPGTh2 are 86% identical overall (76
differences out of 528 amino acids), including 55 differences in the first 300
amino acids of the amino terminus, a domain which confers isoform substrate
specificity. The data indicate a high level of conservation in the amino terminus
is not required for the preservation of substrate specificity. Analysis of
glucuronidation activity encoded by UDPGTh1/UDPGTh2 chimeric cDNAs constructed at
their common restriction sites, Sac I (codon 279), Nco I (codon 385), and Hha I
(codon 469), showed that nine amino acids between residues 385 and 469 are
important for catalytic efficiency, suggesting that this region represents a
domain which is critical for catalysis but distinct from that responsible for
aglycon selection. Screening of leukocyte DNA cosmid library with human UDPGT-Br1
(1-470 bps) or UDPGT-Br2 (1-450 bps) resulted in three overlapping clones, which
were isolated and mapped by endonucleases. Construction of subclones and DNA
sequencing, Southern blot analysis revealed that a cluster of 4 exons (132, 88,
220, 1032 bps in one clone) encodes the entire region of 3' identity shared
between human UDPGT-phenol, human UDPGT-Br1 and human UDPGT-Br2. A similar
strategy but using probes which correspond to the unique regions of human UDPGT
Br1 and human UDPGT-Br2 showed that the exon 1 of UGT1A and UGT1D encodes the
unique region of human UDPGT-Br1, and human UDPGT-Br2 and is located 5.6 and 49
Kb, respectively, upstream of the 4 common exons.
PMID- 9760451
TI - Genetic polymorphism of conjugating enzymes and cancer risk: GSTM1, GSTT1, NAT1
and NAT2.
PMID- 9760452
TI - Primary liver cancer: natural toxins and prevention in China.
PMID- 9760453
TI - Fine structural changes and apoptotic cell death by T-2 mycotoxin.
PMID- 9760454
TI - Monitoring of aflatoxin exposure by biomarkers.
AB - Epidemiological studies have demonstrated a strong association between exposure
to AFB1 and an increased incidence of human hepatocellular carcinoma (HCC). This
association has led to a need for accurate techniques relating AF exposure to an
individual's risk of developing disease. With the understanding of the
progressive processes of carcinogenesis, opportunities for the identification of
molecular biomarkers reflecting events from exposure through clinical disease are
provided. However, the development of biomarker methods to monitor human exposure
to AFs requires techniques which are sensitive, specific, and amenable to large
numbers of samples. To better understand the role of AF exposure with respect to
HCC incidence, immunoassays for the biological quantitation of free AFB1, its
metabolites, and its adduct macromolecules have been developed. ELISA appears to
offer a suitable method for use in epidemiological studies for monitoring short
term exposure to AFs, as it has the appropriate sensitivity and specificity.
However, the presence of substances that are presumably not AFs and which are
inhibitory in the ELISA system has necessitated the development of purification
techniques, usually based on adsorption onto Sep-Pak C18 cartridges and
immunoaffinity chromatography. Many protocols have been developed for the assay
of soluble AF metabolites in urine, milk and blood. However, these assays only
indicate recent exposure, whereas the presence of albumin-AFB1 adducts in
peripheral blood could present a useful material for assessing longer-term
exposure. Among the various possible biomarkers of AF exposure, the measurements
of AF-DNA and -protein adducts are of major interest because they are direct
products of damage to a critical cellular macromolecular target. In Thailand, AF
contamination of foods was reported to be high. More recent data using biomarkers
as measures of AF exposure will be discussed. The data from epidemiological
studies, AF exposure assessment using AF-albumin adduct and urinary AF level as
exposure markers as well as the prevalence of p53 mutation at codon 249 are all
suggestive of a limited importance of AF in the etiology of HCC in this country
compared to other areas, including parts of Africa and China. These results also
indicate that research on other potential hepatocarcinogens should not be
neglected.
PMID- 9760455
TI - Mycotoxins and health hazards: toxicological aspects and mechanism of action of
fumonisins.
PMID- 9760456
TI - How aspartame prevents the toxicity of ochratoxin A.
AB - The ubiquitous mycotoxin ochratoxin A (OTA) is found as a frequent contaminant of
a large variety of food and feed and beverage such as beer, coffee and win. It is
produced as a secondary metabolite of moulds from Aspergillus and Penicillium
genera. Ochratoxin A has been shown experimentally to inhibit protein synthesis
by competition with phenylalanine its structural analogue and also to enhance
oxygen reactive radicals production. The combination of these basic mechanisms
with the unusual long plasma half-life time (35 days in non-human primates and in
humans), the metabolisation of OTA into still active derivatives and glutathione
conjugate both potentially reactive with cellular macromolecules including DNA
could explain the multiple toxic effects, cytotoxicity, teratogenicity,
genotoxicity, mutagenicity and carcinogenicity. A relation was first recognised
between exposure to OTA in the Balkan geographical area and Balkan Endemic
Nephropathy (BEN) with a high incidence (nearly 50 times higher than normal) of
urinary tract tumours. Exposure rates of OTA are measurable in blood of humans
and animals and are established in several countries including Scandinavia,
Germany, France, Italy, Canada, Japan and Northern Africa mainly Tunisia and
Egypt. The impact of OTA exposure in non- endemic areas in the world is not
known, the rates of exposure being not correlated with the disease records,
especially in developed countries, due to lake of well- designed epidemiological
studies, genetic polymorphism and maybe to dietary contents of radical scavengers
and antioxidants. However the incidence and mortality rates of renal cancer are
increasing in European countries and Northern Africa which could be a global
resultant of human exposure to natural compounds in food such as mycotoxins and
especially ochratoxin A. In addition to special care to prevent the growth of
moulds and detoxification measures there was a need for the prevention of the OTA
induced toxic effects once the toxin is ingested. For this purpose several
compound have been studied including some therapeutic agents such as piroxicam
which cannot be proposed for a large scale use in humans for preventive purpose.
Among other compounds, Aspartame, already used as sweetener has shown a real
effectiveness in vivo confirmed largely in vitro. When rats exposed to OTA (289
micrograms/kg) by oral route every two days are given 25 mg/kg similarly for
several weeks, all the toxic effects including genotoxicity are very efficiently
prevented as shown for example by the disappearance of DNA- adducts in tissues
excised from treated animals. Aspartame is also effective in washing out the
toxin when given afterwards to animals intoxicated by the same oTA doses for
several weeks. In vitro, provided that it is added in cell culture medium before
OTA it prevent significantly the inhibition of protein synthesis and lipid
peroxidation induced by the toxin. Obviously the molecular mechanism mediating
the preventive effect of Aspartame is the delivery of phenylalanine by cleavage
of the peptide but also the direct effect of the peptide on the bending capacity
and transport of the toxin in vivo and in vitro. As a matter of fact when
Aspartame is given to animals or added in culture medium the amount of peptide
found unchanged (10-15%) may account for a preventive effect as entire peptide.
PMID- 9760457
TI - Current status of aflatoxin and its control in Thailand.
PMID- 9760458
TI - Toxicity of beta-amyloid peptide.
PMID- 9760459
TI - Excitatory amino acids and lead-induced neurotoxicity.
AB - The NMDA receptor non-competitive antagonist, [3H]MK-801, was used as a ligand
for an autoradiographic study to determine the effects of lead on NMDA receptor
in rat brain. Adult male rats were given lead acetate, 100 mg/kg, or sodium
acetate, 36 mg/kg (control), by i.p. for 7 days. Lead levels were detected in
blood (41.1 micrograms/dl) and brain (16.7-29.4 micrograms/g). Concentrations of
lead in various brain regions did not differ. [3H]MK-801 binding was
heterogeneous throughout the brain with the following order of binding densities:
hippocampal formation > cortex > caudate-putamen > thalamus > brainstem. Lead
exposure caused a decrease in [3H]MK-801 binding to NMDA receptors in the
hippocampal formation including CA2 stratum radiatum, CA3 stratum radiatum and
presubiculum, and in the agranular insular, cingulate, entorhinal, orbital,
parietal and perirhinal areas of cerebral cortex. In another experiment, female
rats were exposed pre- and post-natally from the 4th +/- 1 post conception day
with 1,000 ppm lead in their drinking water. This treatment continued after
weaning. No effects of lead on [3H]MK-801 binding were found at postnatal day
(PM) 28. However, lead caused a significant increase in [3H]MK-801 binding in the
hippocampus including CA1 and CA2, and in the occipital and temporal cortical
areas at PN 56 and at PN 112. Increases in [3H]MK-801 binding were also found in
entorhinal cortex and dentate gyrus at PN 112. The hippocampal formation is a
critical neural structure for learning and memory processes, whereas cortical and
subcortical regions are involved in the modulation of complex behavioral
processes. NMDA receptors have been shown to play a key role in synaptic
plasticity underlying learning and memory. Therefore, lead-induced alterations of
ligand binding to NMDA receptors in the hippocampal formation and cortical areas
may play a role in lead-induced neurotoxicity.
PMID- 9760460
TI - Mechanism of MPP(+)-induced cytotoxicity in human neuroblastoma SH-SY5Y.
PMID- 9760461
TI - Territrem: neurotoxicity and biotransformation.
PMID- 9760462
TI - Research on drug dependence and epidemiological investigation of drug abuse in
China.
PMID- 9760463
TI - Substance abuse in Taiwan and the role of clinical toxicology in its prevention
and treatment.
PMID- 9760464
TI - Drug abuse trends and epidemiological aspects of drug associated deaths in Korea.
PMID- 9760465
TI - Drug abuse and toxicological scene in Japan.
PMID- 9760466
TI - Toxicokinetic parameters in the management of poisoning: an example of
podophyllotoxin intoxication.
PMID- 9760468
TI - Toxicokinetics: concepts and applications.
PMID- 9760467
TI - Toxicokinetics and safety factors in risk assessment.
AB - For risk assessment of anticholinesterase pesticides, acetylcholinesterase
inhibition is a sensitive, reversible indicator of exposure. However, use of
smaller factors when data are available in human may not be justified in some
specific cases. Direct action of anticholinesterase on receptor sites at various
cell types in different target organs may yield to the more severe nature of
toxicity. At the present time, uncertainties exist due to our limited capability
to clarify many human diseases with complex etiology. The toxicokinetic models
available may not accommodate some type of toxicants which their mode of action
involve haemodynamic change or vascular cell injury. Anticholinesterase
pesticides are still widely used in many asian countries to control a variety of
pest species in agricultural practices. The physiology of the effects of these
agents are complex and appropriate uncertainty or "safety factors" are needed to
be acknowledged and taken into account from total exposure. Risk assessment of
anticholinesterase agents is related to complex biological system and we will
probably, never, at least in our lifetimes, know everything we would like to know
to assess risk. We can only do our best with current information available.
However, one should be extremely careful and holistic when applying these
uncertainties in risk assessment of anticholine-esterase pesticides.
PMID- 9760469
TI - Biochemical and pharmacological properties of thrombin-like protein from
Agkistrodon caliginosus.
PMID- 9760470
TI - Mutagenicity and antimutagenicity of flavonoids extracted from Millingtonia
hortensis L.
PMID- 9760471
TI - Pharmacology and toxicology of herbal medicine: subacute toxicity of commonly
used Chinese drugs.
PMID- 9760472
TI - Protective effect of a traditional medicine, shimotsu-to, on brain lesion in
rats.
PMID- 9760473
TI - Lead--the toxic metal to stay with human.
AB - Lead has been known to be toxic to most living things at high dose. It is found
naturally in earth and present in almost all parts of the environment, such as
foods, air, water, dust, soil, paint, and tissues of living organisms including
human. This metal is being used in various aspects including the manufacturing of
storage batteries, production of chemicals, paints and gasoline additives. It is
also used to make various metal products, e.g. sheet lead, solder, and pipes.
Human exposure to lead is mainly from foods and other environments. However, it
is expected that exposure to environmental lead is normally excessive and
produces toxic effects. The well-known and excessive environmental exposures are
air of industrial and heavy traffic areas. Use of leaded gasoline has caused the
main lead pollution for years in almost every big city. Therefore, city
inhabitants normally exposed to lead much more than those who live in the rural
area. The most vulnerable groups at risk to lead exposure are fetuses and
preschool age children. Young children in the 2-3 year-old age may be the most at
risk for exposure to contaminated soil. Adults are affected when exposure is
excessive in the working place and causing lead poisoning. Toxicities are mainly
on heme biosynthesis, neurological effects including encepharopathy, peripheral
neuropathy, and most importantly on I.Q. deficits. It also affects renal tissues
to produce acute and chronic nephropathy and elevated blood pressure. There are
studies of lead exposure of various means and the effects on human health, both
in children and adults. Lead in environment and human exposure are expected to
stay with us for long to come, due the still required lead use in many fields,
particularly the use of lead in storage batteries and others. The magnitude of
exposure will depend solely on the control of use by not allowing the
contamination of lead in our environment to be excessive.
PMID- 9760474
TI - Occupational and environmental lead poisoning: case study of a battery recycling
smelter in Taiwan.
AB - The rapid industrialization in Taiwan has caused both prosperity and
environmental pollution. The purpose of this study is to demonstrate a case of
both occupational and environmental lead poisoning. A patient of lead poisoning
initiated a survey of the battery recycling factory, which revealed that 31 of 64
workers suffered from lead poisoning. Children who attended a nearby kindergarten
showed a significant increase of blood lead up to 15-25 micrograms/dl and a mild
but significant decrease of IQ (intelligent quotient, by Binet-Simon scale) if
compared with children of a nonexposed but socioeconomically comparable
kindergarten. Outdoor workers of the nearby forging factory also showed a
significant increase of blood lead if compared with indoor workers or workers of
another nonexposed forging factory 20 Km away. Air sampling showed an average of
more than 10 micrograms/m3 in the kindergarten. Soil sampling and analysis also
revealed 400 folds increase of lead content, which decreased if the sample was
taken deep down to 15-30 cm or 350 meters away from the battery recycling
smelter. Moreover, after children were moved away from the pollution source,
follow-up examination performed 2.5 years later showed a significant decrease of
blood lead and partial recovery of IQ among them.
PMID- 9760475
TI - Effects of Mg and K deficiency on male and female mice.
PMID- 9760476
TI - Biological monitoring of metabolites of sarin and its by-products in human urine
samples.
AB - More than 20,000 passengers of Tokyo underground trains were intoxicated with
warfare toxic chemicals. Most of the patients examined had marked miosis and
decreased serum cholinesterase activity. Transient increase of serum CPK activity
after 3 days of the exposure was the another sign. We intensively analyzed the
metabolites in the urine of 4 patients. The following analytic results indicated
the exposure to sarin as well as contaminated compounds such as diisopropyl
methylphosphonate (DIMP), ethyl methylphosphonate fluoridate (EMPF, or
ethylsarin), diethyl methylphosphonate (DEMP), and ethyl isopropyl
methylphosphonate (EIMP). (1) Isopropanol (IPA) and ethanol (EtOH) were detected
of large quantities in the urine samples, and were thought to be derived from
sarin and the sarin counterpart, EMPF, DIMP, DEMP and EIMP. (2) Monoalkyl
methylphosphonic acids (isopropyl methylphosphonic acid (IMPA) and ethyl
methylphosphonic acid (EMPA) also were excreted in large amounts with taking the
similar excretion pattern of IPA and EtOH. (3) The metabolite only derived from
sarin and ethylsarin is F anions whose integral output in the urine was less than
the equimolar level of the excreted (IMPA + EMPA + IPA + EtOH). (4) Other
corroborative findings were low lethality: of more than 5,510 patients treated,
11 were acutely dead. (5) Nine exposed males had higher sister chromatid exchange
(SCE) rate (5.00 +/- 1.48/cell) than the control (3.81 +/- 0.697/cell), because
dialkyl methylphosphonates seemed to have alkylating activity and producing DNA
adducts. The SCE rate also increased after the in vitro exposure of lymphocytes
to dialkyl methylphosphonates.
PMID- 9760477
TI - Recent progress of the international harmonization of toxicological testing:
impact and implementation of ICH guidelines. International Conference
Harmonization.
PMID- 9760478
TI - Testing human pharmaceuticals for carcinogenic potential: new approach in ICH
process. International Conference Harmonization.
PMID- 9760479
TI - Harmonization of genotoxicity testing requirements for pharmaceuticals.
PMID- 9760480
TI - Recent progress of the international harmonization of toxicological testing:
toxicokinetics.
PMID- 9760481
TI - Registration of toxicologists in Europe.
AB - Recently several European Toxicological Societies have established national
toxicology registers. Such societies include the British, Dutch, Finnish, French,
Hungarian, and Swiss societies of toxicology. The basis for registration in these
societies is peer review evaluation of the applicants. A key-criterion for
acceptance is theoretical training covering the main areas of toxicology.
Furthermore, job experience is required. After reviewing the merits of the
applicant, the register then accepts the applicant to the register usually for
five years. As a consequence of this development, EUROTOX, European Societies of
Toxicology, has established a European Register of Toxicologists which will be
officially inaugurated during 1997. The register already contains more than two
hundred British, Dutch, Finnish, and German toxicologists. The European Register
of Toxicologists already has had an impact on the recognition of toxicology in
Europe, and will strive to promote toxicology education and professional status
in other parts of the world.
PMID- 9760483
TI - The recent situation and future perspectives of the certification of
toxicologists.
PMID- 9760482
TI - Recent situation and future perspectives of the certification of toxicologists.
PMID- 9760484
TI - Recent situation and future perspective of the certification of toxicologist in
Japan.
PMID- 9760485
TI - The present and future of poison control center in Taiwan.
AB - The PCC-Taiwan was founded in July 1985 under the auspices of the Department of
Health, Executive Yuan, and the Veterans General Hospital-Taipei, Republic of
China. It has served a population of 21 million inhabitants on a 24-hours basis.
It has also served as a referral center for treating poisoning cases nationwide,
a training center for physicians and consultants, and a center for Analytical
Toxicology. The average annual volume of telephone inquires to PCC is more than
four thousand in recent few years and continue to increase annually. The present
and future prospective of the PCC-Taiwan which have to be accomplished are: 1. to
propagate public education of poisoning prevention and increase the utility of
PCC before events of intoxication, 2. to establish, computerize and improve the
database and network of domestic poisonous products or natural toxins, including
herbs, 3. to establish an nationwide referral network for severely poisoned
patients or cluster poisoning events, 4. to build up a global collaborative work
with other poison centers.
PMID- 9760486
TI - Recent situation of prevention, preparedness and response to chemical accidents
in the Republic of Korea.
PMID- 9760487
TI - Recent situation of the poison center in Thailand.
PMID- 9760488
TI - Psychic dependent potential of dihydroetorphine.
PMID- 9760489
TI - Introduction to plant virology.
PMID- 9760490
TI - Introduction to classical crossprotection.
PMID- 9760491
TI - History of coat protein-mediated protection.
AB - A decade of research has proven that plants can be genetically engineered to
resist virus infection through expression of viral CP genes, as well as other
viral genes and sequences. Additional opportunities for development of resistant
plants will require research focused on mechanisms of protection, improvements in
expression vector design, and transformation of new crop species. As each of
these technologies is utilized singly or in combination to generate resistant
crop varieties, the full impact of such engineered resistance will be realized.
PMID- 9760492
TI - Geminivirus isolation and DNA extraction.
PMID- 9760493
TI - Caulimovirus isolation and DNA extraction.
PMID- 9760494
TI - Reovirus isolation and RNA extraction.
PMID- 9760495
TI - Procedures for plant rhabdovirus purification, polyribosome isolation, and
replicase extraction.
PMID- 9760496
TI - Hordeivirus isolation and RNA extraction.
PMID- 9760497
TI - Furovirus isolation and RNA extraction.
PMID- 9760498
TI - Tobravirus isolation and RNA extraction.
PMID- 9760499
TI - Tobamovirus isolation and RNA extraction.
PMID- 9760500
TI - Potexvirus isolation and RNA extraction.
PMID- 9760501
TI - Carlavirus isolation and RNA extraction.
PMID- 9760502
TI - Potyvirus isolation and RNA extraction.
PMID- 9760503
TI - Trichovirus isolation and RNA extraction.
PMID- 9760504
TI - Ilarvirus isolation and RNA extraction.
PMID- 9760505
TI - Bromovirus isolation and RNA extraction.
PMID- 9760506
TI - Cucumovirus isolation and RNA extraction.
PMID- 9760507
TI - Nepovirus isolation and RNA extraction.
PMID- 9760508
TI - Comovirus isolation and RNA extraction.
PMID- 9760509
TI - Carmovirus isolation and RNA extraction.
PMID- 9760510
TI - Tymovirus isolation and genomic RNA extraction.
PMID- 9760511
TI - Tombusvirus isolation and RNA extraction.
PMID- 9760512
TI - Luteovirus isolation and RNA extraction.
PMID- 9760513
TI - RNA analysis. Size and 3' end group determination.
PMID- 9760514
TI - RNA fractionation by density gradient centrifugation.
PMID- 9760515
TI - cDNA library construction for the lambda ZAP-based vectors.
PMID- 9760516
TI - PCR cloning of coat protein genes.
PMID- 9760517
TI - Antibody production.
PMID- 9760518
TI - Expression library screening.
PMID- 9760519
TI - In vitro transcription and translation.
PMID- 9760520
TI - Analysis of coat protein expression cassettes in protoplasts.
PMID- 9760521
TI - DNA sequencing.
PMID- 9760522
TI - Computer analysis of amino acid sequences. The case of plant virus capsid
proteins.
PMID- 9760523
TI - Preparation of coat protein-containing binary vectors for use in Agrobacterium
mediated transformation.
PMID- 9760524
TI - Potato transformation.
PMID- 9760525
TI - Transformation of tomato.
PMID- 9760526
TI - Tobacco transformation.
PMID- 9760527
TI - Genetic transformation of wheat.
PMID- 9760528
TI - Production of transgenic rice (Oryza sativa subspecies japonica cv. Taipei 309).
PMID- 9760529
TI - Molecular analysis of transgenic rice.
PMID- 9760530
TI - PCR analysis of transgenic tobacco plants.
PMID- 9760531
TI - Southern analysis of transgenic tobacco plants.
PMID- 9760532
TI - Detection and quantification of transcript RNA in transgenic plants using
digoxigenin-labeled cDNA probes.
PMID- 9760533
TI - Western analysis of transgenic plants.
PMID- 9760534
TI - Assaying levels of plant virus by ELISA.
PMID- 9760535
TI - Detection of plant RNA viruses by nonisotopic dot-blot hybridization.
PMID- 9760536
TI - Detection and quantification of plant viruses by PCR.
PMID- 9760537
TI - Assaying levels of virus with local lesion hosts.
PMID- 9760538
TI - Field testing resistance of transgenic plants.
PMID- 9760539
TI - Agronomic performance of transgenic plants.
PMID- 9760540
TI - Mechanisms of resistance. Expression of coat protein.
AB - Expression of viral CP genes in transgenic plants can lead to virus resistance by
interference of either the transcript or the protein with virus infection.
Dependence of resistance on CP accumulation can be most convincingly shown by
comparison of plants that accumulate CP with plants that accumulate a
nontranslatable CP transcript. Even in cases in which CP accumulation is
required, the degree of resistance does not always correlate with CP levels in
transgenic plants. In cases in which CPMR can be overcome by inoculation with
viral RNA instead of virions, interference with virion disassembly is the likely
cause of resistance. Classical crossprotection can also sometimes be overcome by
RNA inoculation, and, in this case, appears to work by a similar mechanism. There
is no evidence yet that CPMR is caused by a nonspecific plant defense response
that might be triggered by the accumulating CP. Measurement of virus accumulation
in protoplasts prepared from transgenic plants was used to show interference with
early events of virus infection. There is no clear evidence yet for inhibition of
local virus spread in transgenic plants. A reduced rate of virus accumulation in
inoculated leaves can usually also be explained with reduced rate of replication.
However, in the case of CPMR to CMV, it appears that early events, as well as
systemic spread, are affected. Reduced vector transmission of virus infection
from inoculated transgenic plants to nontransgenic plants has been observed. It
is not known whether this is just a consequence of lower virus levels in the
transgenic plants or whether direct interference with acquisition and
transmission by the vector is also involved. In addition to virion formation, CP
can function in different ways in plant virus infections. Replication, long
distance spread, and vector transmission can also depend on the presence of CP.
Expression of genes encoding nonfunctional CPs in transgenic plants can be tried
in order to interfere with normal CP function. Knowledge of CP function(s) in a
particular plant-virus interaction will be useful to design gene constructs.
Since CP accumulation levels in transgenic plants do not always correlate with
resistance, newly generated transgenic plant lines are now frequently tested for
virus resistance before further characterization. However, if the objective of a
transformation experiment is also to study the mechanism of CPMR, it is necessary
to determine transcript and protein levels in the transgenic plants. Gene
constructs encoding nontranslatable and antisense CP transcripts should be
included in the experiment. If possible, transgenic plants should be inoculated
with virions and viral nucleic acid, and replication in isolated protoplasts
should be determined.
PMID- 9760541
TI - Mechanisms of RNA-mediated resistance to plant viruses.
PMID- 9760542
TI - Detection of risks associated with coat protein transgenics.
PMID- 9760543
TI - Potential benefits of the transgenic control of plant viruses in the United
Kingdom.
PMID- 9760544
TI - [Vascular ischemic dementia].
AB - Observations are reported of the course and other interrelations between clinical
pattern and computer tomography results in 36 patients with vascular ischaemic
dementia. Attention is called to the frequency of transient dementia-like
disturbances following stroke and to the importance of the middle gyrus of the
left frontal lobe in the development of dementia manifestations. In cases with
slow progression of dementia symptoms and only scant neurological signs not
infrequently long-standing improvement or even complete remission of dementia
symptoms occur which sets them apart from mixed forms of dementia. The problem of
the occurrence of isolated dementia syndromes of sudden onset is discussed and
for them the term "stroke with dementia" is proposed.
PMID- 9760545
TI - [Carotid artery disease in patients with ischemic stroke. Results of year-long
observation conducted within the framework of prospective epidemiological
studies, Warsaw, 1991-1992].
AB - A cohort of 297 patients with ischaemic stroke were followed for one year.
Doppler ultrasonography, done in 219 patients (109 women and 110 men), aged 68.0
+/- 12.6, revealed a concomitant carotid artery occlusive disease (CAD) in 76
patients (34.7%), 34 women and 42 men, aged 66.5 +/- 11.1, 45 of them had high
grade stenosis (> 75%) or occlusion. Claudication, myocardial infarction and
hypercholesterolaemia diagnosed before the onset of stroke was found more often
in patients with CAD, 11.1%, 22.2% and 4.4% was versus 2.8%, 12.3% and 1.4% in
patients without CAD. Prevalence of other stroke risk factors, hypertension,
diabetes, angina in both groups of patients was similar. Severe stenosis or
occlusion was diagnosed more often among men (58%) and among smokers (55%), in
the group of patients without CAD than 48% and 42% respectively. The onset of
stroke was preceded more often by TIA--24% in group with CAD, versus 17% in
patients without CAD. Neurological state on admission, test by Stroke Severity
Scale and Weakness Score according to SDB, was similar in both groups of patients
but prognosis was worst among patients with CAD, 13.5% of them developed
recurrent stroke versus 7% in group without CAD. In Kaplan-Meier analysis one
year cumulative survival rates were lower in the group of the patients with
severe stenosis or occlusion.
PMID- 9760546
TI - [Clinical types of Guillain-Barre syndrome].
AB - A detailed history and the results of the physical examination of seven patients
with unusual and not typical Guillain-Barre syndrome were described. The patients
presented various levels of lesions and some signs and symptoms were not typical
of classic clinical features. The variety of the clinical picture suggests the
damage of nervous system in many places and at various levels, not only in the
peripheral nerves, but also in the central nervous system. The heterogeneity of
aetiology and aetiopathogenesis and immunological individual patient's reaction
probably is the cause of the involvement of different structures.
PMID- 9760547
TI - [Facial hemispasm: modern views on the etiology, pathogenesis and treatment.
Personal experience with botulinum A toxin treatment].
AB - The authors present current opinions on the etiology and strategies of treatment
of hemifacial spasm. In the vast majority of patients it is caused by compression
of facial nerve by redundant loops of vertebral and basilar arteries and their
branches. It was confirmed by neuroradiology imaging techniques and during
surgical interventions. In recent years a new, non-invasive method of treatment
has gained a wide approval--the local injections of botulinum toxin A into
contracting muscles is a highly effective (90%) and safe method of treatment. Our
own material (10 patients, 22 sessions) confirms it as well.
PMID- 9760548
TI - [The assessment of lamotrigine effectiveness in patients with drug-resistant
epilepsy].
AB - The aim of the study was to evaluate the efficacy of lamotrigine (LTG, Lamictal)
in patients with long-lasting epilepsy. The group of 11 patients, 4F, 7M aged 16
45 years, mean 31.3 years was included in the study. Complex partial seizures and
complex partial with sec. generalization ones occurred in 5 patients, only simple
and complex partial seizures in 4 and in 2 cases we observed primary generalized
nonconvulsive seizures. The mean seizure frequency was 20/month before LTG
treatment. The mean duration of epilepsy was 20 years. Monotherapy with
carbamazepine was used in 2 patients, 9 took 2 antiepileptic drugs. The time of
investigation and treatment was 4 months with 3 control visits. During LTG
treatment the number of conventional antiepileptic drugs was reduced in 7
patients. The dose of the basic antiepileptic drug was not changed. We evaluated
how LTG had influenced the frequency, severity and duration of seizures,
patients' mental state and adverse events appearance. Good result of treatment-
seizure frequency reduction at least 50%--was observed in 5 patients (45.5%),
moderate--seizure frequency reduction below 50%--in 1 patient (9%), bad result-
no change in seizure frequency or its increase--in 5 cases (45.5%). In 5 patients
the drug influenced positively seizure severity and duration. Beneficial
psychotropic effect of the drug was found in 2 patients with mental disturbances.
Adverse effects occurred in 3 patients. They were vertigo and ataxia in 1
patient, drowsiness in 1 case and dyspeptic symptoms in 1 patient. Adverse events
were mild and transient in 2 patients. In 1 patient with vertigo and ataxia they
resulted in the drug being discontinued after 3 month treatment. On the whole
lamotrigine shows a positive influence on the frequency, severity and duration of
seizures in some patients with therapy resistant epilepsy. The drug is well
tolerated and seems to have positive psychotropic effects.
PMID- 9760549
TI - [Hereditary sensorimotor neuropathy in electrophysiological studies].
AB - We performed clinical and electrophysiological studies in 42 children with
hereditary motor and sensory neuropathy type I and II (HMSN I and II) and in 103
members of their families. In 24 families with HMSN I the conduction velocity and
latency were markedly changed in the nerves innervating the distal muscles
(median, peroneal nerves) as well as proximal muscles (facial, axillary and
musculocutaneous nerves). The changes were uniform in all motor and sensory
nerves studied in a particular patient. The intensity of changes was similar in
members of their families even when the clinical abnormalities were minimal, thus
the degree of conduction velocity slowing was uniform within families. In adults
with HMSN I (group A i B) we found less marked slowing of nerve conduction as
compared to children (group P), the difference being significant (p < 0.001). It
may suggest a slow process of peripheral nerves maturation despite the existing
morbid condition. In patients of 18 families with HMSN II slight changes in
conduction velocity were found only in nerves innervating the distal muscles,
more evident in legs (peroneal and sural nerves). Conduction time of facial,
axillary and musculo-cutaneous nerves was normal. The values of nerve conduction
were not changing with patients' age. We recommend examining conduction time in
facial, axillary or musculocutaneous nerve as a useful procedure for
differentiation between HMSN I and II, especially in families with borderline
conduction values in the nerves innervating distal muscles.
PMID- 9760550
TI - [Prognostic significance of transient hyperglycemia in acute phase of ischemic
stroke].
AB - Experimental studies of different stroke models equivocally showed that
hyperglycaemia is responsible for the increase of infarct volume and mortality.
Similar results were obtained in several, but not all clinical studies. The aim
of the study was to assess the occurrence and prognosis of transient
hyperglycaemia in non-diabetic, acute ischaemic stroke patients. A consecutive
series of 204 patients admitted to the Stroke Unit within 48 hours after the
onset of the first-ever hemispheric ischaemic stroke, confirmed by CT and/or
autopsy, were included in the study. Blood samples for determination of glucose
level were obtained immediately after admission, on the 1-st, 2-nd, 3-rd, 5-th, 7
th and 14-th day of stroke. The fructosamine and HbA1 measurements were used to
exclude patients with previous glucose intolerance. The severity of stroke was
assessed according to Scandinavian Neurological Stroke Scale on admission, on the
first, 7-th, 14-th and 30-th day of stroke. Transient hyperglycaemia, defined as
at least one elevated glucose level in the first week of stroke with normal level
of HbA1 and fructosamine was found in 65 (31.9%) of patients. Patients with
transient hyperglycaemia did not differ from diabetics and normoglycaemic
according to age, gender, history of hypertension and other risk factors. 30 day
mortality in the group of patients with transient hyperglycaemia was
significantly higher than in normoglycaemic ( p. < 0.001) and diabetic patients.
Transient hyperglycaemic patients died earlier, mainly on the 7-th day after
admission whereas patients with normoglycaemia died mainly on the 18-th day (p <
0.0001). The main reason of death in hyperglycaemic patients were cardiac
complications (15/20), in normoglycaemic--the consequences of immobility (8/11)
(< 0.01). The results of our study showed that the transient hyperglycaemia
occurred in about one third of acute ischaemic stroke patients and resulted in
higher 30-day mortality.
PMID- 9760551
TI - [The usefulness of intraoperative high-frequency doppler flowmetry in surgeries
for intracranial aneurysms].
AB - The flowmeter enables estimation of blood flow velocity changes in small calibre
arteries. The authors examined blood flow velocity patterns in the vessels during
aneurysm operations and blood flow velocity and its disturbances inside aneurysm.
Evaluation technique, technical data of the flowmeter use are described and the
characteristics of the blood flow velocity picture in cerebral arteries obtained
by this method is presented. The presented method enables a very precise
estimation of blood flow velocity and detection of changes in flow patterns. The
method may become very helpful in identification of the vessels in other types of
cerebral surgery.
PMID- 9760552
TI - [The study of the role of intervertebral disc neovascularization and immune
response in the pathogenesis of lumbar discopathy].
AB - In adult humans moral intervertebral disc (id) is an avascular tissue and becomes
so called sequestrated autoantigen. Any acquired defect of anulus fibrosus may
potentially lead to contact of immunocompetent cells circulating in the blood
with id antigens thus inducing autoimmune reaction. 34 patients operated on
because of lumbar discopathy were studied. The id injury was divided into: a)
protrusion, B) simple prolapse, c) subligamentous prolapse, d) sequester. The
samples of surgically removed id were subjected to histopathological and
immunohistochemical study. Presence of granulation tissue, neovascularization and
humoral response (confirmed by immunopositive reaction to factor VIII and IgG)
was found in decreasing pattern in the following groups: I) sequesters, 2) simple
prolapses, and 3) subligamentous prolapses. Among protrusions there were only two
cases positive for IgG. A negative reaction to C3bR was seen in all the groups of
id. The obtained results suggest that immune reaction against lumbar id is rather
an effect than a cause of its herniation.
PMID- 9760553
TI - [Sleep apnea syndrome in acromegalic patients].
AB - The aim of this report was to analyse the sleep apnea rate and its clinical
picture in acromegaly patients before and after the surgical treatment. The
authors investigated both hormones levels and spirometric coefficients. They
found, that surgical removal of microadenoma from transphenoidal approach led to
the fast regression of the syndrome.
PMID- 9760554
TI - [Enzymatic activity in cerebrospinal fluid in the monitoring of the brain lesions
following intracranial tumors].
AB - After intracranial tumour surgery edema, ischaemic and haemorrhagic changes are
developing in the brain. It causes leakage of certain intracellular components
and enzymes into extracellular and cerebrospinal fluid. This study includes 46
patients operated on for cerebral tumours. Lumbar CSF was obtained in
postoperative course and the activity of AST, ALT, LDH, alpha HBDH, CK, gamma GT
and oxygen concentration were estimated. In the control group were 10 patients
suffering from sciatic pain and CSF was obtained during radiculography. For
diagnostic and prognostic purposes of biochemical markers statistical analyse
methods were employed and comparisons with clinical factors were carried out. In
conclusions we suggest that enzymes AST, alpha HBDH, CK and oxygen content give
valuable additional information of postoperative brain damage.
PMID- 9760555
TI - [Modern views on the pathogenesis of Wilson's disease].
AB - Wilson's disease is a rare, multiorganic genetically coded disorder, induced by
impaired copper transport. The recent identification of the disease gene and the
discovery of gene product--copper transporting P-type ATPase that is integrate
membranous protein has contributed greatly to better understanding of the
pathogenesis. This protein is probably essential for incorporation of copper into
ceruloplasmin and for its biliary excretion. Multiple mutations of Wilson's
disease gene are responsible for the excess of so called "free" copper which is
toxic to tissues. Copper toxicity involves first of all, functional disorders of
many enzymatic systems, particularly those of respiratory chain enzymes. In the
central nervous system, a special kind of copper toxicity is medicated by
astroglia, so that a direct, harmful effect of both copper and ammonia on the
brain is observed. The authors present a current review on biochemical mechanisms
of copper toxicity and physiopathological significance of the CNS astroglia in
Wilson's disease.
PMID- 9760556
TI - [The role of protein C in the pathogenesis of stroke].
AB - This paper presents the role of inhibitory protein C in the haemostatic
processes, types of its deficiency and current opinions concerning the role of
protein C deficiency in the pathogenesis of stroke. Deficiency of protein C (PC)
or activated protein C resistance (both hereditary and acquired) play a role in
pathogenesis of stroke, but not so great as it was thought until quite lately.
Isolated protein C deficiency in old patients does not increase the risk of
stroke. But in children hereditary deficiency of PC or activated PC resistance
are of great importance in pathogenesis of ischaemic or venous stroke. In the
presence of additional risk factors both in children and in adults deficiency of
PC may be an important condition leading to stroke occurrence.
PMID- 9760557
TI - [Severe meningoencephalitis in Borrelia burgdorferi infection].
AB - We present a case of borreliosis with severe impairment of central nervous
system. The patient a 43-year-old man, presented with neurological signs and
symptoms and severe psychiatric disorders. The diagnosis was established several
months after the onset of neurological signs. CSF examination revealed lymphocyte
pleocytosis and specific antibodies against B. burgdorferi in high titres. MRI of
the brain showed inflammatory lesions. Due to the treatment with antibiotics,
patient's state improved and pleocytosis in CSF disappeared. However, after 1-
year follow-up, specific antibodies were still present in high titres. Clinical
manifestations and the results of diagnostic procedures show multifocal
encephalitis in the acute phase of the disease and encephalopathy as a residual
syndrome.
PMID- 9760558
TI - [Abdominal migraine in adults].
AB - A case of a 35-year-old woman with abdominal migraine is presented. For four
years she had been suffering from abdominal pains occurring only at night, always
between 1 and 3 a.m. The patient always woke with abdominal pains and nausea.
Each time she had diarrhoea and vomited and found that this gave her relief from
the pain. Sometimes she lost consciousness for 1-2 minutes. After the attack she
felt very weak, her legs and feet became numb and she found it difficult to get
to sleep. The attacks and the fainting fits increased in frequency until she had
several a month. Numerous gastrological examinations did not reveal any
deviations from the normal. At the anti- epileptic consulting unit, abdominal
epilepsy was excluded (no abnormalities were found in the eeg and CT examinations
of the cranium). As a child she had paroxysmal abdominal pains. When the patient
was 10 years old, she had an attack lasting one week and though the pain was
severe on the left side, appendectomy was performed. Her mother suffers from
migraine with very severe head pains. The patient was referred to our consulting
unit where she was treated with Pizotifen in doses of 0.5 mg morning and noon and
1 mg in the evening for three months during which time she had no attacks. A few
weeks after discontinuing this treatment, the nocturnal attacks again occurred
though the pains were not so severe. She was then prescribed Nitrendipine, 5 mg
nightly, and the attacks ceased. However, the patient said that she had felt
better when taking Pizotifen.
PMID- 9760559
TI - [Diagnostic difficulties in a case of multifocal changes in the brain in
computerized tomography and in magnetic resonance imaging].
AB - This paper presents a case of multifocal metastases in the brain, which on the
basis of typical imaging magnetic resonance and computerized tomography suggested
possible parasitic changes (cerebral cysticercosis). On the basis of these
pictures cerebral cysticercosis was diagnosed, in spite in the absence of
serologic changes in blood and cerebrospinal fluid. The lack of improvement after
anticysticercosis drugs, the further course of the disease as well as new foci
located in other organs outside the brain, allowed to recognize numerous
metastases in the brain although until the end of the clinical observation the
primary lesion of the neoplasm was not found. The histopathological examination
of samples of brain tissue confirmed the diagnosis of numerous metastases of
poorly differentiated carcinoma.
PMID- 9760560
TI - [Subarachnoid hemorrhage due to conus medullaris ependymoma].
AB - A case of conus medullaris tumour (ependymoma) is reported in which the
presenting symptom was subarachnoid haemorrhage, which has left bladder
dysfunction. 70-year-old patient was admitted to the Department of Neurology due
to symptoms of conus medullaris lesion with retention of urine and diminished
pain sensitivity in perianal zona. He had been hospitalized 30 years ago due to
vomiting, headache and pain in lumbar region. The cerebrospinal fluid examination
confirmed the diagnosis of subarachnoid haemorrhage. Cerebral angiography failed
to show the source of bleeding. Myelography and spinal arteriography showed nor
tumour neither vascular malformation. Only MRI examination performed after 30
years following the first symptoms of tumour made possible the correct diagnosis-
tumour in vertebral canal at L1-L2 level compressing conus medullaris. Surgical
procedure confirmed the diagnosis. Histopathological examination--ependymoma
myxopapillare.
PMID- 9760561
TI - [Endoscopic brain surgery of intracranial cysts: report of 2 cases].
AB - Two cases are presented of intracranial cystic lesions, which were treated by the
neuroendoscopic method. In the two cases the patients' radiological and clinical
conditions improved. Neuroendoscopy is a very effective and safe method to treat
intracranial cystic lesions.
PMID- 9760562
TI - [A case of schizophrenia-like psychosis in a patient with arachnoid cyst].
AB - The aim of this report was the presentation of the extremely rare case of the
arachnoid cyst of the brain, with only psychiatric manifestation. According to
the literature and own experience the authors conclude, that the treatment of
these patients would be interdisciplinary, both neurosurgical and psychiatric.
PMID- 9760563
TI - [Response to the letter by Ewa Nachman, Mark Nachman and Halina Zblowska on the
paper "A contribution to the microanatomy of the initial segment of the long
middle artery (Heubner's)" published in Neurol. Neurosurg. Pol., 1997, 31, 4,
727...].
PMID- 9760564
TI - [Letter concerning the paper by Stefan Bayassi and Stefan Kopczynski: "Traumatic
intracranial hematomas: analysis of 54 cases" published in Neurol. Neurosurg.
Pol., 1997, 31, 4, 727...].
PMID- 9760565
TI - [Report on the congress on treatment and studies on multiple sclerosis, Istambul
(Turkey), Nov. 2-5, 1997].
PMID- 9760566
TI - [Report on the First training course of the Stroke Association of the Central
East Europe in Prague, Dec. 3-7, 1997].
PMID- 9760567
TI - Immunological tolerance. Introduction.
PMID- 9760568
TI - Mechanisms of peripheral T cell tolerance.
AB - Peripheral tolerance to self proteins is induced because these antigens are
presented to T lymphocytes under conditions that do not allow effective immune
responses to develop, or because the responses of the specific T cells are
tightly regulated. The two principal mechanisms of peripheral tolerance are
activation-induced cell death (AICD) and anergy. In CD4+ T lymphocytes, AICD is
induced by repeated stimulation, with high levels of interleukin (IL)-2
production. Under these conditions, the T cells co-express Fas (CD95) and Fas
ligand (FasL), and engagement of Fas triggers apoptotic death of the T cells.
Mice with defects in Fas, FasL, IL-2R alpha or beta chain exhibit defects in AICD
and develop autoimmune disease. The induction of T cell anergy is dependent on
the recognition of B7 co-stimulators by the inhibitory T cell counter-receptor,
CTLA-4. Failure of anergy is the likely basis for the fatal autoimmune disease of
CTLA-4 knockout mice. The single-gene defects that result in autoimmunity are all
defects in lymphocyte regulation, indicating that tolerance is often maintained
by the control of lymphocyte responses to self antigen. The existence of distinct
pathways of T cell tolerance suggest that different types of antigens induce
tolerance by distinct mechanisms.
PMID- 9760569
TI - B cell antigen receptor signalling in the balance of tolerance and immunity.
AB - The quantity and quality of signals from the B cell antigen receptor (BCR) drives
the positive and negative selection of B lymphocytes and establishes the balance
of tolerance and immunity. Experiments using immunoglobulin transgenic mice and
mutations in key BCR signalling components have given insight into how the
antigen receptor is tuned and how thresholds for qualitatively different outcomes
are established and maintained. This research also describes how genetic variants
can shift the balance between autoimmunity and tolerance.
PMID- 9760570
TI - The study of self-tolerance using murine haemoglobin as a model self antigen.
AB - T cell tolerance to self proteins involves both thymic and peripheral mechanisms.
We have used allotypic differences in murine haemoglobin (Hb) to study the
development of tolerance to the abundantly expressed self-protein. In Hb beta s/H
2k mice, the response to Hb beta d is directed against Hb beta d (64-76)
presented by I-Ek molecules. Using T cell hybridomas and clones specific for this
epitope, we have demonstrated that Hb(64-76)/I-Ek complexes and present on
antigen-presenting cells in all lymphoid organs including dendritic cells, B
cells and macrophages. In the thymus, the presence of these complexes results in
negative selection of transgenic T cells with high levels of Hb(64-76)/I-Ek
specific receptor. However, cells with intermediate levels of specific receptor
escape negative selection and can be found in the periphery. Under normal
circumstances these cells remain tolerant, but can be activated by mechanisms
which increase the number of Hb(64-76)/I-Ek complexes.
PMID- 9760571
TI - Tolerance and determinant hierarchy.
AB - The overall T cell response to a multideterminant antigen consists of the sum of
responses to a limited number of different determinants on the protein. Antigen
presenting cells (APCs) are crucial in delimiting the determinants on the protein
to which a response will be mounted. This influence is apparent at two levels.
First, the determinants that are generated and displayed by APCs in the thymus
are pivotal in shaping the T cell repertoire that will be available for
responding to antigen determinants in the periphery. Second, antigen processing
affects the selection of determinants that become displayed by the various
peripheral APC populations that are involved in inducing and promoting a T cell
response. We have studied the effect of the display hierarchy on tolerance
induction to individual determinants in transgenic mice expressing different
serum levels of hen egg lysozyme. We have also analysed aspects of the processing
machinery that contribute to shaping the hierarchy of determinant display on MHC
class II molecules: proteolysis and reduction of disulfide bonds.
PMID- 9760572
TI - Molecular genetic studies in lymphocyte apoptosis and human autoimmunity.
AB - Using a genetic approach, we have studied the molecular basis of human
autoimmunity with special emphasis on a disease that is due to defective
lymphocyte apoptosis. Recently, we and our collaborators have found that the
autoimmune/lymphoproliferative syndrome (ALPS), an inherited disease of children
comprising marked lymphoid hyperplasia and autoimmune manifestations, is due to
abnormalities in the CD95 gene that cause defective lymphocyte apoptosis. Our
recent investigations have shown that the mutations in most families with ALPS
cause either global or local changes in the structure of a cytoplasmic portion of
the molecule called the 'death domain'. These death domain alterations impair
binding of the adapter protein FADD/MORT1 and result in a failure to activate
apoptotic caspases after CD95 (Fas/APO-1) cross-linking. Mutations in apoptotic
caspases may also contribute to the pathogenesis of ALPS in individuals that have
no CD95 gene mutations.
PMID- 9760573
TI - A role for CTLA-4-mediated inhibitory signals in peripheral T cell tolerance?
AB - Occupancy of the antigen receptor is not sufficient for activation of naive T
cells--additional co-stimulatory signals are required that can be provided only
by 'professional' antigen-presenting cells. This two-signal model for T cell
activation has been thought to provide a mechanism for the induction and
maintenance of peripheral tolerance. Work over the past six years has
demonstrated that the relevant co-stimulatory receptor on T cells is the molecule
CD28. Recent data shows that the CD28 homologue CTLA-4 plays a role in negative
regulation of T cell responses. Here we suggest that CTLA-4 may also serve as an
attenuator of T cell-activating signals, raising the threshold of stimulation
required to obtain full activation. The inhibitory signals mediated by CTLA-4 may
provide an additional mechanism for the maintenance of peripheral tolerance.
PMID- 9760574
TI - Antigen-specific CD4+ T cells that survive after the induction of peripheral
tolerance possess an intrinsic lymphokine production defect.
AB - Injection of soluble foreign antigen without an adjuvant induces a state of
antigen-specific immunological unresponsiveness. We investigated the cellular
mechanisms that underlie this form of peripheral tolerance by physically tracking
a small population of ovalbumin (OVA) peptide/I-Ad-specific, CD4+ T cell receptor
(TCR) transgenic T cells following adoptive transfer into normal recipients.
Injection of OVA peptide in the absence of adjuvant caused the antigen-specific T
cells to proliferate for a brief period after which most of the T cells
disappeared. The remaining OVA-specific T cells had converted to a memory
phenotype but were poorly responsive in vivo as evidenced by a failure to
accumulate in the draining lymph nodes following immunization with OVA peptide in
adjuvant. These surviving T cells possessed a long-lasting, but reversible,
defect in Il-2 and TNF-alpha production and in vivo proliferation, but did not
gain capacity to produce Th2-type cytokines or suppress the clonal expansion of T
cells specific for another antigen. Therefore, some antigen-specific T cells
survive this peripheral tolerance protocol but are functionally unresponsive due
to an intrinsic activation defect.
PMID- 9760575
TI - Antigen-specific tolerance induction and the immunotherapy of experimental
autoimmune disease.
AB - Antigen-specific tolerance induction is the ultimate goal for specific
immunotherapy of autoimmune diseases. Here we will discuss recent experiments
designed to induce tolerance following mucosal administration of antigens in a
mouse model of experimental autoimmune encephalomyelitis (EAE). We were unable to
induce oral tolerance either with whole myelin, myelin basic protein (MBP) or the
immunodominant peptide antigen. Oral tolerance was possible, however, with an
analogue of the immunodominant peptide modified to increase its affinity for the
restricting major histocompatibility complex (MHC) antigen. By contrast,
intranasal deposition of peptide antigen proved highly effective for both
prevention and treatment of EAE. Prevention of disease was directly related to
the antigenic property of the peptide which, in itself, was related to affinity
for MHC. Notably, administration of a single peptide was shown to inhibit disease
involving multiple epitopes. We investigated the resulting bystander regulation
by studying the cellular basis of peripheral tolerance in a transgenic model.
These studies indicate that bystander regulation may be the consequence of
selective cytokine secretion.
PMID- 9760576
TI - Quantitative and qualitative control of antigen receptor signalling in tolerant B
lymphocytes.
AB - Lymphocyte antigen receptors, such as the B cell antigen receptor (BCR), have the
ability to promote or inhibit immune responses. This functional plasticity is
exemplified by BCR-induced mitosis in naive but not tolerant B cells and is
correlated with biochemical differences in the signals triggered by foreign and
self antigens. Acute stimulation of naive B cells with foreign antigen induces a
biphasic Ca2+ flux, and activates nuclear signalling through NF-AT, NF-kappa B,
JNK and ERK. In tolerant B lymphocytes, by contrast, self antigen triggers only a
low Ca2+ plateau, NF-AT and ERK. After removal from self antigen, the BCRs on
tolerant B cells reacquire the ability to stimulate a biphasic Ca2+ flux and to
promote proliferation. The differences in nuclear signalling between naive and
tolerant cells is brought about in part by differences in the magnitude of the
Ca2+ signal. A low, sustained Ca2+ signal, such as that seen in tolerant B cells,
activates NF-AT, whereas, a high but transient Ca2+ spike, which resembles that
triggered in naive B cells, activates NF-kappa B and JNK. These findings
demonstrate that the quantitative differences in Ca2+ signalling between naive
and tolerant B cells are reversible and contribute to the differential triggering
of nuclear signals. The activation of selected transcription factors may in turn
account for the different functional responses triggered in naive and tolerant
lymphocytes.
PMID- 9760577
TI - Tolerance induction with CD4 monoclonal antibodies.
AB - One of the major goals of therapeutic immunosuppression is to be able to use
short-term therapy to achieve long-term tolerance. Short courses of CD4
antibodies are able to create peripheral tolerance in a mature immune system. The
resulting tolerant state shows evidence of being dominant in that one can observe
the features of linked suppression, transferable suppression and infectious
tolerance in a variety of model systems. Only in the situation of administration
of high doses of marrow could one find evidence of central and peripheral
tolerance which had all the features of being deletional rather than regulatory.
These findings suggest that attaining dominant tolerance and linked suppression
may be the least invasive of all tolerance-inducing strategies for clinical
application.
PMID- 9760578
TI - A two-step model for the induction of organ-specific autoimmunity.
AB - Peripheral tolerance is considered to be a safeguard against autoimmunity but the
mere existence of anergic T cells renders them potentially dangerous. Using
transgenic mice that were tolerant to a foreign MHC class I antigen (Kb)
exclusively expressed in the liver, we investigated whether reversal of tolerance
in vivo would directly result in autoimmunity. Breaking of tolerance was achieved
by application of tumour cells expressing both Kb and interleukin 2. Despite the
fact that the respective mice were now able to reject Kb-positive grafts, the
reversed T cells did not infiltrate and attack the Kb-positive liver. However,
when the liver was 'conditioned' through an inflammatory reaction either by
irradiation or by infection with Listeria, massive T cell infiltration and liver
damage were observed in the reversed mice. The results show that at least two
steps are required for autoimmunity: (1) activation of antigen-specific T cells,
and (2) conditioning of the target organ. It will be important to determine the
factors leading to conditioning but it is likely that adhesion molecules are
involved. These experiments are not only of relevance for treatment of autoimmune
disease but also for tumour therapy.
PMID- 9760579
TI - Cross-presentation of self antigens to CD8+ T cells: the balance between
tolerance and autoimmunity.
AB - Upon encounter with foreign antigen, tissue-associated antigen-presenting cells
(APCs) migrate to draining lymph nodes to prime specific T cells. Using the
transgenic RIP-mOVA model, we recently demonstrated that self antigens derived
from peripheral tissues are constitutively transported to draining lymph nodes,
and can be presented in association with MHC class I molecules by a bone marrow
derived APC population. This form of class I-restricted presentation of exogenous
antigen has been referred to as cross-presentation and can induce activation and
proliferation of antigen-specific CD8+ T cells. In the absence of CD4+ T cell
help, activation of CD8+ T cells is inefficient, and cross-presentation leads to
peripheral deletion of autoreactive CD8+ T cells, acting as a mechanism to
maintain self-tolerance. If CD4+ T cell help is available, CD8+ T cell responses
to self antigens can be rendered immunogenic, leading to autoreactive responses.
Whether autoimmunity results from such responses also depends on the tissue
location of the antigen. In RIP-mOVA mice, which express the model antigen mOVA
(a membrane-bound form of ovalbumin) in the pancreatic beta cells and kidney
proximal tubules, OVA-specific CD8+ T cells, activated by cross-presentation,
infiltrated the pancreas and caused B cell destruction. Interestingly, however,
these cells did not infiltrate the kidney, suggesting that proximal tubular cells
are to some extent protected from immune destruction. Analysis of the role of
antigen concentration indicates that high doses were required for efficient cross
presentation, suggesting that this pathway is directed towards immune responses
to high-dose antigens, such as may be present during viral infection.
PMID- 9760580
TI - Tolerance induction in mature T lymphocytes.
AB - T lymphocytes with self-destructive capacity are often found in healthy
individuals, indicating efficient control mechanisms that prevent autoimmunity.
Recently, we were able to demonstrate the existence of peripheral tolerance in
double-transgenic mice expressing the foreign histocompatibility antigen H-2Kb
exclusively outside the thymus and a T cell receptor (Des.TCR) directed against
the Kb molecule. In mice expressing Kb only on keratinocytes anti-Kb T cells were
still present but failed to reject Kb-positive tissue grafts. This observation
would imply a continuous migration of naive T cells exported from the thymus into
non-lymphoid tissues where these fresh thymic emigrants would need to be
tolerized. However, this is in contrast to the view that migration to peripheral
tissues is restricted to activated T cells. To investigate whether there is a
continuous process of tolerization of naive T cells in adult DES.TCR x 2.4Ker-Kb
mice, 2.4Ker-Kb mice were crossed with Rag-2-deficient mice and reconstituted
with bone marrow cells of Des.TCR transgenic mice (Des.TCR x 2.4Ker-Kb.Rag-2-).
Tolerance was not observed in these chimeric mice. We conclude from these results
that in contrast to the neonate the adult physiological environment does not
allow tolerance induction to antigens expressed on keratinocytes in T cells newly
exported from the thymus. Furthermore, we have to postulate regulatory events
responsible for the maintenance of peripheral tolerance in the adult Des.TCR x
2.4Ker-Kb animals.
PMID- 9760581
TI - T lymphocyte-mediated control of autoimmunity.
AB - Autoreactive T cells can be readily identified in the peripheral lymphocyte pool
of both humans and experimental animals. Peripheral tolerance may be maintained
by regulatory/suppressor T cells which prevent the activation of autoantigen
specific cells. Mice thymectomized on day 3 of life (d3Tx) develop a wide
spectrum of organ-specific autoimmune diseases. Reconstitution of d3Tx mice with
CD4+ CD25+ T cells from normal mice prevents the development of disease.
Similarly, CD4+ CD25+ T cells prevent the transfer of disease by autoantigen
specific cloned T cells derived from d3Tx mice. Thus, regulatory T cells can
prevent both the induction and effector function of autoreactive T cells. In
vitro, the CD4+ CD25+ population is anergic to stimulation through the T cell
receptor (TCR) and suppresses the proliferative responses of normal CD4+ CD25-
cells by a contract-dependent mechanism. Suppression is not MHC-dependent, but
requires activation of the CD4+ CD25+ population. The mechanism of suppression in
vivo and the target antigen(s) of this unique regulatory population remain to be
characterized.
PMID- 9760582
TI - Resting energy expenditure and nitrogen balance in critically ill pediatric
patients on mechanical ventilation.
AB - Nutritional support is important in critically ill patients, with variable energy
and nitrogen requirements (e.g., sepsis, trauma, postsurgical state) in this
population. This study investigates how age, severity of illness, and mechanical
ventilation are related to resting energy expenditure (REE) and nitrogen balance.
Nineteen critically ill children (mean age, 8 +/- 6 [SD] y and range 0.4-17.0 y)
receiving total parenteral nutrition (TPN) were enrolled. We used indirect
calorimetry to measure REE. Expected energy requirements (EER) were obtained from
Talbot tables. Pediatric Risk of Mortality (PRISM) and Therapeutic Intervention
Scoring System (TISS) score were calculated. Total urinary nitrogen was measured
using the Kjeldahl method. PRISM and TISS scores were 9 +/- 5 and 31 +/- 6
points, respectively. REE was 62 +/- 25 kcal.kg-1.d-1, EER was 42 +/- 11 kcal.kg
1. d-1, and caloric intake was 49 +/- 22 kcal.kg-1.d-1. Nitrogen intake was 279
+/- 125 mg.kg-1.d-1, total urinary nitrogen was 324 +/- 133 mg.kg-1.d-1, and
nitrogen balance was -120 +/- 153 mg.kg-1.d-1. The protein requirement in this
population was approximately 2.8 g.kg-1.d-1. These critically ill children were
hypermetabolic, with REE 48% higher (20 kcal.kg-1.d-1) than expected. Nitrogen
balance significantly correlated with caloric and protein intake, urinary
nitrogen, and age, but not with severity of illness scores or ventilatory
parameters.
PMID- 9760583
TI - Lifestyle factors fail to explain the variation in plasma leptin concentrations
in women.
AB - To assess the relationship between circulating leptin concentrations, metabolic
parameters, and lifestyle factors such as alcohol intake, physical activity
level, smoking habits, and reproductive history, a cohort of 359 women was drawn
from a population-based study conducted in Victoria, Australia. The parameters
measured included body mass index (BMI); waist and hip circumference; blood
pressure; and fasting glucose, insulin, triacylglycerol, cholesterol, and leptin
concentrations. In addition, a self-administered questionnaire was used to assess
reproductive history, physical activity level, alcohol intake, and smoking
habits. Our results demonstrated that BMI, body weight, waist circumference, and
hip circumference were all strongly correlated with circulating leptin
concentrations in this population (r > 0.56, P < 0.001 in all cases). Waist/hip
ratio, triacylglycerols, insulin, glucose, and cholesterol were also associated
with leptin (P < 0.05), but there was no association between leptin and age,
height, or blood pressure. When these associations were adjusted for BMI, age,
glucose, and waist circumference were significantly associated with leptin. The
lifestyle factors examined did not help to explain the observed variation in
leptin concentrations between individuals when results were adjusted for degree
of adiposity and age.
PMID- 9760584
TI - Bioelectrical impedance analysis in human immunodeficiency virus-infected
patients: comparison of single frequency with multifrequency, spectroscopy, and
other novel approaches.
AB - Bioelectrical impedance (BIA), a prediction method for estimating body water
compartments and body cell mass (BCM), is being increasingly used in studies of
human immunodeficiency virus (HIV)-related wasting, but there are few validation
studies of the method in this group. The aim of this study is to examine the
relationship between impedance measurements and body water compartments in
patients with advanced HIV disease, and to investigate whether the newer
approaches of multifrequency BIA, BIA spectroscopy, logarithmic transformation
using a parallel circuit model, and direct calculation from electrical theory
offer any advantage over traditional single-frequency BIA. We measured total body
water (TBW) by deuterium dilution and extracellular water by bromide dilution in
33 patients with advanced HIV disease. Intracellular water and BCM were
calculated from these results. Impedance was measured over a range of frequencies
using a multifrequency analyzer. The relationship between impedance index at
various frequencies and body water compartments was assessed by correlation and
linear regression. We found that impedance index at higher frequencies had a
closer relationship to TBW (r = 0.86, standard error of the estimate [SEE] = 2.96
at 1000 kHz) and at lower frequencies a closer relationship to extracellular
water (ECW) (r = 0.47, SEE = 3.13 at 0 kHz) than the traditional 50 kHz
measurement (r = 0.84, SE = 3.11 for TBW; r = 0.44 SEE = 3.19 for ECW), but the
differences were marginal and not statistically significant. None of the other
novel approaches tested were significantly better than traditional single
frequency measurement. The 50 kHz equation for BCM developed in this study [BCM
(kg) = (0.360331 x Ht2/Z50) + (0.151123 x Wt)-2.95] may be useful to
investigators using BIA for hIV-wasting studies.
PMID- 9760585
TI - Total parenteral nutrition supplemented with medium-chain triacylglycerols
prevents atrophy of the intestinal mucosa in septic rats.
AB - Total parenteral nutrition (TPN) is associated with an increased incidence of
bacterial translocation (BT) compared with enteral nutrition because of the
disuse atrophy of the intestine. In this study, we assessed the effect of adding
medium-chain triacylglycerols (MCT) to TPN for the prevention of mucosal atrophy
in the intestine. Rats were subjected to either fat-free TPN, TPN with long-chain
triacylglycerols (LCT), or TPN with MCT for 5 d and nutrition parameters were
evaluated. In another set of rats receiving the same TPN regimen, 0.8 or 0.05
mg/kg endotoxin was administered on day 4. Survival was evaluated and BT to the
mesenteric lymph nodes, liver, and systemic blood was measured 24 h later. The
mucosal heights of the jejunum and ileum were evaluated concurrently. The
survival rate was significantly improved in the MCT group (P < 0.05) at the
endotoxin dose of 0.8 mg/kg. The nutrition condition presented by phospholipid,
total cholesterol, and total ketone body levels was the best in the MCT group
compared to the other groups. The intestinal villous height in the ileum was
significantly greater in the MCT group. However, the improvement of BT in MCT
group was not statistically significant. In this endotoxin-challenged rat model,
survival rate was improved by the supplementation of MCT. This effect may be
presented in some part by the improvement in nutrition condition and by the
prevention of mucosal atrophy in the intestine.
PMID- 9760586
TI - Automated, eight-cage indirect calorimetry in rats.
AB - We have constructed an automated, eight-cage indirect calorimeter (AIC) for the
measurement of energy expenditure in rats. We compared the measurements of
resting energy expenditure (REE) in rats during a 30-h fast obtained with the AIC
with those obtained with a manual indirect calorimetry (MIC) system. There was
both a high degree of correlation between the two techniques during the initial
18 h of the fast (r = 0.90, P < 0.05) and strong intertechnique agreement. REE
(AIC) decreased during the final 12 h of the 30-h fast (79.6 +/- 2.7-72.0 +/- 4.4
kcal.kg-0.75.d-1 [mean +/- SD, P < 0.01]). REE (MIC) did not show a significant
decrease during this part of the fast (79.7 +/- 2.6 - 75.2 +/- 4.7 kcal.kg-0.75.d
1 [P = NS]). During the final 12 h of the fast agreement between the two systems
gradually dissipated and correlation was poor (r = 0.375, P < 0.05). The
frequency of animal handling necessitated by MIC may have resulted in a stress
induced increase in metabolic work that would mask the animals' adaptive response
to starvation. This investigation demonstrates the advantages of the AIC and
calls into question the accuracy of manual methods under long-term starvation
conditions.
PMID- 9760587
TI - Alterations in N-acetylation of 3-methylhistidine in endotoxemic parenterally fed
rats.
AB - N-methylhistidine (3-meH) is endogenously released during muscle catabolism and
serves as a marker of protein turnover. In rats > 85% of 3-meH is excreted in the
urine as the N-acetyl derivative. It has been reported that the percent of non
acetylated 3-meH (NA-3-meH) varies minimally with stress. To further evaluate
these reports we randomized 39 male Sprague-Dawley rats (157-213 g) to receive
parenteral nutrition only (PN) or PN plus continuous infusion of Escherichia coli
026:B6 lipopolysaccharide at 6 (LPS-6) or 12 (LPS-12) mg.kg-1.d-1 for 48 h. All
animals received isocaloric and isonitrogenous PN 24 h before and throughout the
study with water ad libitum. Total 3-meH excretion was significantly increased (P
< 0.05) in the LPS-6 (470 +/- 136 micrograms/48 h) and LPS-12 (557 +/- 171
micrograms/48 h) groups versus the PN (331 +/- 126 micrograms/48 h) group. NA-3
meH differed significantly between the LPS-12 (218 /+- 89 micrograms/48 h, LPS-6
(94 +/- 48 micrograms/48 h), and PN (39 +/- 12 micrograms/48 h) groups (P <
0.05). Percent NA-3-meH increased significantly from 12.7 +/- 3.9% in the PN
group to 19.8 +/- 8.0 and 39.9 +/- 12.8% in the LPS-6 and LPS-12 groups,
respectively (P < 0.05). No significant changes in acetyl 3-meH were found
between groups. These data suggest that either saturation or inhibition of
acetylation pathways occurs with increasing levels of stress. Due to the
disproportionate increases in NA-3-meH and percent NA-3-meH during endotoxemia,
only total 3-meH should be used as an indicator of protein turnover in rats.
PMID- 9760588
TI - Bioactivation of the proximal food mutagen 2-hydroxyamino-1-methyl-6
phenylimidazo[4,5-b]pyridine (N-OH-PhIP) to DNA-binding species by human mammary
gland enzymes.
AB - We have investigated phase II activation of the food-derived mutagen 2
hydroxyamino-1-methyl-6-phenyl[4,5-b]pyridine (N-OH-PhIP) by cytosolic
acetyltransferase, sulfotransferase, and tRNA synthetase/kinase enzymes from
human breast tissue. Cytosol from homogenates of mammary gland tissue obtained
from breast-reduction surgery or mastectomy was incubated with and without enzyme
specific cofactors, and mutagen binding of calf thymus DNA was quantified by 32P
postlabeling. In addition, microsomal fractions of mammary epithelial cells from
some individuals were examined for prostaglandin H synthetase activation of N-OH
PhIP. Our results show that all four enzymes can participate in activating N-OH
PhIP, thus inducing PhIP-DNA adduct formation in human mammary cells. However,
not all individuals exhibited all these activities; instead each individual
showed a combination of one or more activation pathways. The present findings
demonstrate that the human mammary gland has the capacity to metabolically
activate a dietary mutagen by several enzyme systems, including
acetyltransferase, sulfotransferase, tRNA synthetase/kinase, and prostaglandin
hydroperoxidase catalysis.
PMID- 9760589
TI - Improvement of coronary artery disease in a patient with hyperhomocysteinemia:
report of a case.
PMID- 9760590
TI - Cytoprotective properties of melatonin: presumed association with oxidative
damage and aging.
AB - For years melatonin, a molecule widely produced in both the plant and animal
kingdom, was thought to function exclusively as a synchronizer of seasonal
reproduction, adjuster of the biological clock, sleep-inducing agent, and immune
system stimulator. More recently melatonin has also been found to be a free
radical scavenger and antioxidant. Although pharmacologic levels (higher than
those normally present endogenously) of melatonin possess substantial protective
activity against molecular damage inflicted by free radicals, its role as a
physiologic antioxidant is currently under active investigation. Toxic free
radicals have been implicated in a variety of age-associated degenerative
diseases, as well as in aging itself. Because melatonin production falls
substantially during aging, the loss of this antioxidant is theorized to be
instrumental in the degenerative processes associated with advanced age. The
exogenous administration of melatonin has been found to be effective in reducing
macromolecular damage that is normally seen in experimental models of age-related
disease. How effective melatonin will be in terms of deferring aging, however,
must await the outcome on subsequent studies.
PMID- 9760591
TI - Compatibility and stability of additives in parenteral nutrition admixtures.
AB - The addition of additives (electrolytes, trace elements, and vitamins) to
parenteral nutrition (PN) mixtures can lead to precipitation as a result of
physical incompatibilities and can lead to chemical degradation of individual
ingredients. The most significant cause of precipitation is excessive
concentrations of calcium phosphate. The most significant cause of chemical
instability is the oxidation of specific vitamins. The factors influencing
calcium phosphate solubility include the commercial amino acid source, the
calcium and phosphate salts used, temperature, magnesium concentration, and final
volume. Precipitation can be avoided by organic phosphates. Trace element
precipitation is most commonly caused by the formation of iron phosphate salts or
copper cysteinate in cysteine-containing amino acid infusions. The least stable
nutrient is ascorbic acid, which reacts with oxygen, and is catalyzed by copper
ions. Oxygen originates from PN ingredients, the filling process, air remaining
in the bag after filling, and oxygen permeation through the bag wall. Storage in
multilayered bags with reduced gas permeability can protect residual ascorbic
acid. Other chemical losses are caused by the reduction of thiamine by
metabisulfite, and photodegradation of daylight-sensitive vitamins, especially
retinol and riboflavin, during administration.
PMID- 9760592
TI - Bioelectrical impedance analysis in nutritional research.
PMID- 9760593
TI - Contribution by skeletal muscle to whole-body protein catabolism in critical
illness: usefulness of urinary 3-methylhisitidine excretion.
PMID- 9760594
TI - Food-derived carcinogens and breast cancer risk.
PMID- 9760595
TI - Antioxidants and aging: is melatonin a possible, practical new hope?
PMID- 9760596
TI - Dietary management of patients with hepatic encephalopathy in hospitals in the
United Kingdom.
PMID- 9760597
TI - Elimination of intraluminal colonization by antibiotic lock in silicone vascular
catheters.
PMID- 9760598
TI - Ceramides and ceramide metabolites in cell regulation: evidence for dietary
sphingolipids as inhibitors of colon carcinogenesis.
PMID- 9760599
TI - Lipid peroxidation of intravenous fat emulsions: a pharmaceutical issue with
clinical impact?
PMID- 9760600
TI - Diet and breast cancer.
PMID- 9760601
TI - Is downsizing and disbanding specialty care teams a counterproductive strategy
for cost reduction in health care?
PMID- 9760602
TI - Dietary supplements.
PMID- 9760603
TI - Evaluation of outcomes for patients with AIDS receiving home total parenteral
nutrition.
AB - This study evaluated the outcomes of patients with acquired immunodeficiency
syndrome (AIDS) provided home total parenteral nutrition (HTPN) when specific
criteria were used to initiate HTPN. Fifteen males who received HTPN and seven
males who consumed only an oral diet were studied. The HTPN patients received an
average of 55 kcal.kg-1.d-1 and 2.0 g of protein.kg-1.d-1 from HTPN and oral
diet. Non-HTPN patients consumed an average of 35 kcal.kg-1.d-1 and 1.2 g
protein.kg-1.d-1. Body weight (BW), lean body mass (LBM), and serum albumin (SA)
were measured when HTPN was initiated or initial nutrition counseling was
provided to the non-HTPN patients and again at the end of the study period. Over
the study period, the HTPN patients gained an average 5.5 kg of BW and 3.0 kg of
LBM, whereas the non-HTPN lost an average of 5.0 kg of BW and 3.0 kg of LBM. BW
and LBM may be used to assess the response to HTPN in AIDS patients.
PMID- 9760604
TI - Gastrostomy without laparotomy: a percutaneous endoscopic technique. 1980.
PMID- 9760605
TI - Combined phacoemulsification and trabeculectomy versus trabeculectomy alone: a
comparison study using mitomycin-C.
AB - BACKGROUND AND OBJECTIVE: To compare the results of combined phacoemulsification
and trabeculectomy (PEM/TRAB) plus mitomycin-C with those of trabeculectomy alone
(TRAB) plus mitomycin-C. PATIENTS AND METHODS: The authors retrospectively
reviewed 42 eyes in 38 consecutive patients who underwent combined PEM/TRAB with
mitomycin-C. An age-matched control group of 42 patients who underwent TRAB with
mitomycin-C during the same time period was randomly selected from 248
consecutive patients. All patients had a minimum of 12 months of follow-up.
RESULTS: Mean preoperative intraocular pressure (IOP) and number of glaucoma
medications were similar for the two groups (22.8 +/- 6.9 mm Hg vs 22.9 +/- 6.8
mm Hg, 2.12 +/- 0.8 vs 2.26 +/- 1.0 medications, combined PEM/TRAB vs TRAB,
respectively). Postoperative IOP was significantly lower at all follow-up
intervals. At final follow-up after a mean of 21.8 +/- 6.0 months, IOP averaged
13.9 +/- 5.1 mm Hg in the PEM/TRAB group and 12.3 +/- 4.7 mm Hg in the TRAB
group. Bleb survival was excellent in both groups, although slightly higher in
the TRAB group (37 of 42 PEM/TRAB vs 41 of 42 TRAB). Both groups required
significantly fewer glaucoma medications at final follow-up (0.38 +/- 0.6 vs 0.5
+/- 0.8, PEM/TRAB vs TRAB). Complications were similar between the two groups.
CONCLUSION: The success rate for combined PEM/TRAB appears to approach that of
TRAB alone.
PMID- 9760606
TI - Episcleral versus combined episcleral and intrascleral application of mitomycin-C
in trabeculectomy.
AB - BACKGROUND AND OBJECTIVE: To determine whether intrascleral exposure to mitomycin
C (MMC) improves the control of intraocular pressure (IOP), increases the
incidence of complications, or both. PATIENTS AND METHODS: The authors
retrospectively evaluated 38 eyes of 29 patients following the intraoperative
application of MMC (0.2 mg/ml; 5 minutes). In 21 eyes the MMC-soaked sponge was
applied to the intact episclera (episcleral group). In 17 eyes, two sponges, one
episcleral and the other intrascleral (sandwich group), were applied. The median
follow-up times were 19.0 (episcleral group) and 24.0 (sandwich group) months.
Outcome measures were the IOP, the number of medications, success rates, and the
incidence of complications. RESULTS: The only statistically significant
difference between the two groups was the 2-week postoperative IOP, which was
significantly lower in the episcleral group (P = .0314). CONCLUSION: Because
there is no additional benefit, the authors recommend that the intrascleral
application of MMC be avoided. However, they did not observe increased
complication rates when MMC was applied in this way.
PMID- 9760607
TI - Transscleral cyclophotocoagulation with the diode laser for neovascular glaucoma.
AB - BACKGROUND AND OBJECTIVE: To compare the outcome of transscleral
cyclophotocoagulation (TSCPC) using a diode laser with that of TSCPC using an
Nd:YAG laser in neovascular glaucoma. PATIENTS AND METHODS: The surgical outcome
of diode laser TSCPC was retrospectively compared with that of free-running mode
Nd:YAG laser (FR-YAG) TSCPC and continuous-wave mode Nd:YAG laser (CW-YAG) TSCPC.
Twenty-one eyes of 21 patients in the diode laser group, 9 eyes of 9 patients in
the FR-YAG group, and 9 eyes of 9 patients in the CW-YAG group were treated.
RESULTS: The Kaplan-Meier life-table analysis revealed that the probability (mean
+/- standard error) of successful intraocular pressure control with diode laser
TSCPC at 3 years postoperatively was 47.2 +/- 12.6% per operation and 55.9 +/-
16.3% per eye. Compared with the CW-YAG TSCPC, the diode laser TSCPC had a
significantly higher probability of success throughout the follow-up period.
Diode laser TSCPC was associated with improvements or preservation of visual
acuity in 16 of 21 eyes (76%), and was the best of the three laser sources.
Postoperative complications were minor following diode laser TSCPC. CONCLUSION:
Diode laser TSCPC appears to be as effective as FR-YAG TSCPC and better than CW
YAG TSCPC for treating neovascular glaucoma.
PMID- 9760608
TI - A trial of dorzolamide for glaucoma.
AB - BACKGROUND AND OBJECTIVE: To determine whether the effectiveness of dorzolamide
changes when the drug is used under routine clinical conditions versus the more
ideal conditions of a clinical trial. PATIENTS AND METHODS: A total of 118 eyes
of 65 patients were assessed. Nine patients (15 eyes) received dorzolamide only,
41 patients (74 eyes) received dorzolamide as an "add-on" medication, and 15
patients (29 eyes) received dorzolamide as a substitute for an oral carbonic
anhydrase inhibitor. RESULTS: At 1 month the intraocular pressure (IOP) had
decreased from 23.5 to 19.9 mm Hg in the patients receiving dorzolamide only,
from 18.6 to 16.4 mm Hg in the patients receiving dorzolamide as an add-on
medication, and from 17.7 to 16.0 mm Hg in the patients receiving dorzolamide as
a substitute for an oral carbonic anhydrase inhibitor. Similar decreases in IOP
were present at 3 and 6 months. Local drug reactions occurred in 3 patients. Five
patients stopped treatment because of severe symptoms of nausea and prostration.
CONCLUSION: Under routine clinical conditions, dorzolamide was effective as a
sole medication and as an add-on medication. It was at least as effective as oral
acetazolamide. Local drug reactions sometimes occurred, as did systemic
reactions.
PMID- 9760609
TI - Corneal refractive and endothelial changes following THC:YAG (holmium) laser
sclerostomy.
AB - BACKGROUND AND OBJECTIVE: To determine the effect of THC:YAG (holmium) laser
sclerostomy on corneal curvature and endothelial cell counts. PATIENTS AND
METHODS: One hundred twenty-five cases were reviewed for high postoperative
corneal astigmatism (> 5 D) or preoperative and postoperative endothelial cell
count measurements in eyes without preoperative evidence of corneal endothelial
compromise. RESULTS: Nine patients had keratometry reading at 2 to 3 months with
documented corneal astigmatic changes of 5.62 to 12 D (mean 7.27 +/- 2.16 D).
Sixteen eyes of 14 patients studied with specular microscopy had central mean
endothelial cell count reductions of 6.5% following THC:YAG laser sclerostomy.
The total energy applied correlated with the percentage reduction in endothelial
cell counts (r = .507, P = .045, n = 16, Spearman correlation). CONCLUSION:
Higher laser energy levels can result in high corneal astigmatism, which in some
cases may be persistent, and a reduction in endothelial cell count.
PMID- 9760610
TI - Ellipsoidal fitting of corneal topography data after arcuate keratotomies with
compression sutures.
AB - BACKGROUND AND OBJECTIVE: After paired arcuate keratotomies and compression
sutures (AK) for treatment of high postkeratoplasty astigmatism, corneal
topography tends to be irregular. The purpose of this study was to demonstrate a
mathematical method for approximation of discrete corneal topography power data
with an ellipsoid for better appreciation of the clinical outcome after AK.
PATIENTS AND METHODS: Thirty-one eyes of 28 consecutive patient who underwent AK
for excessive postkeratoplasty astigmatism were studied. Regular keratometry,
corneal topography (TMS-1), subjective refraction, and best-corrected visual
acuity (VA) were assessed preoperatively and at 1 week and 1 year
postoperatively. A simplex algorithm was applied for fitting an ellipsoidal
surface to raw corneal topography power data. A set of parameters (meridional
power, axis, and asphericity) were calculated. The cylinder of subjective
refraction was correlated with the keratometric readings, the simulated
keratometry (SimK) of the topography system, and the respective parameters of the
model surface. RESULTS: Keratometric astigmatism and the cylinder of the model
surface decreased from 8.1 +/- 3.2 and 7.9 +/- 2.9 D preoperatively to 4.5 +/-
2.1 and 5.3 +/- 2.0 D after 1 year, respectively. The asphericity in both
meridional cross sections changed from a prolate ellipse preoperatively to an
ablate ellipse at the early postoperative follow-up stage. Regarding the cylinder
axis, there was a significant correlation of the model surface with the
refractive cylinder at all examinations (P < .05), whereas there was no
significant correlation of the SimK axis and the refractive cylinder axis.
CONCLUSION: The approximation of corneal topography power data with an
ellipsoidal model surface renders reconstruction of clinically relevant corneal
topography parameters, including corneal asphericity with a marked data
compression. Even in markedly irregular corneal surfaces, such as after AK, the
correlation of amount/axis of refractive cylinder with the model surface
parameters is more accurate than it is with respective SimK values of corneal
topography analysis.
PMID- 9760611
TI - Capsule-bending ring for the prevention of capsular opacification: a preliminary
report.
AB - BACKGROUND AND OBJECTIVE: To report the preliminary results of a study on the
preventive effect of the capsule-bending ring on anterior and posterior capsule
opacification (ACO and PCO, respectively). PATIENTS AND METHODS: The ring is an
open, band-shaped, circular polymethylmethacrylate (PMMA) ring measuring 11 mm in
diameter with pre-tension (13 mm in diameter when the ring is open), 0.2 mm in
thickness, and 0.7 mm in width. To retain sharp edges, the ring is not polished.
The sharp edges should create a sharp, discontinuous capsular bend in the fornix,
which induces contact inhibition of migrating lens epithelial cells after
cataract surgery. This capsule-bending ring is inserted into the capsular fornix
following phacoemulsification, prior to the implantation of an intraocular lens
(IOL). In a multicenter trial, 100 patients were scheduled to undergo
phacoemulsification and IOL implantation in both eyes within 1 month. The
procedure was performed with the ring in 1 eye and without the ring in the other
eye of each patient. RESULTS: The anterior capsule was prevented from coming into
contact with the IOL, and ACO was significantly reduced in the eyes with the
ring, rendering the capsular opening larger 3 months after surgery. PCO was
obviously reduced on slit-lamp examination in the follow-up period up to 6
months, but needs to be evaluated during a longer period. CONCLUSION: This band
shaped, sharp-edged capsule-bending ring may be useful for cases that need good
fundus visualization for photocoagulation or expected vitreoretinal surgery and
for the prevention of PCO.
PMID- 9760612
TI - Digital palpation of intraocular pressure.
AB - BACKGROUND AND OBJECTIVE: Previous studies investigating the accuracy of digital
palpation through the eyelids to estimate intraocular pressure (IOP) have shown
disappointing results. In this study, the accuracy of digital assessment of IOP
by palpation of the bare cornea is investigated. MATERIALS AND METHODS: The IOP
of a cadaveric eye model was varied from 5 to 40 mm Hg in increments of 5 mm Hg.
Two examiners, one experienced and one inexperienced, digitally palpated the
corneas and estimated IOP. The results were compared before and after a 1-hour
training session. RESULTS: Prior to the training session, the experienced
examiner guessed correctly 46% of the time and was correct within 5 mm Hg 100% of
the time. The inexperienced examiner guessed correctly 21% of the time and was
within 5 mm Hg 62% of the time. After the training session, the experienced
examiner's score did not significantly (38% correct, 88% within 5 mm Hg, P = .05.
CONCLUSIONS: Digital assessment of IOP by palpation of bare cornea is accurate
when performed by experienced individuals. A minimal amount of training using the
eye model may improve one's accuracy.
PMID- 9760613
TI - Histologic effect of diode laser sclerostomy in human cadaver eyes.
AB - BACKGROUND AND OBJECTIVES: To study tissue effects and thresholds of efficacy in
producing a full-thickness scleral fistula in human eyes obtained from cadavers.
The effect of laser sclerostomies created with indocyanine green (ICG) was also
evaluated. MATERIALS AND METHODS: Ab externo laser sclerostomies were produced in
12 fresh human eyes obtained from cadavers using a 200-micron diameter fiber
optic connected to a diode laser system. Power settings were 500, 750, 1000,
1250, 1500, and 2000 mW with a constant duration of 100 and 200 ms. The same
diode laser settings were repeated in the tissues injected with ICG. RESULTS: The
laser sclerostomies were associated with heat coagulation damage adjacent to the
burn margins, with disruption of stromal collagen. Tissue damage was greater at
higher power and longer duration. Scleral injection of ICG prior to laser
sclerostomy did not enhance laser penetration. CONCLUSION: The diode laser can
create a sclerostomy in human sclera with an optimum level of 1500 mW and 100 ms.
ICG did not significantly enhance the ease of penetration or reduce the
association thermal damage to the sclera.
PMID- 9760614
TI - Treatment of total hyphema with relatively low-dose tissue plasminogen activator.
AB - The purpose of this study is to investigate the efficacy of tissue plasminogen
activator (tPA) in the treatment of total hyphema following ocular trauma or
intraocular surgery. Three patients (3 eyes) representing unresolved total
hyphema for more than 5 days and uncontrolled high intraocular pressure received
intracameral injections of 10 microgram of recombinant tPA. Intracameral tPA
injection resulted in complete resolution of hyphema in all 3 eyes. Resolution
occurred mostly within 24 to 48 hours after injection. Possible side effects of
tPA injection, such as increased intraocular pressure and corneal edema, were not
observed. However, 1 eye had vitreous hemorrhage after repeated injections of
tPA. Intracameral injection of tPA seems to be a safe and effective method for
the treatment of unresolved total hyphema. However, repeated intracameral tPA
injections may cause unwanted complications such as vitreous hemorrhage.
PMID- 9760615
TI - Corneal marginal ulcer in relapsing polychondritis: treatment with
keratoepithelioplasty.
AB - This article describes a case of corneal marginal ulcer caused by relapsing
polychondritis (RPC) that was treated with keratoepithelioplasty. The patient
underwent keratoepithelioplasty with lamellar keratoplasty in the left eye. No
relapse occurred in the nasal side in which corneal lenticules were grafted,
whereas vascular invasion developed in the temporal side in which no lenticules
were grafted. Keratoepithelioplasty was an effective surgical procedure to
prevent a recurrence of corneal marginal ulcer in a patient with RPC.
PMID- 9760616
TI - A pre-swedged silicone tube to simplify pigtail canaliculoplasty.
AB - Silicone intubation of the canalicular system is indicated for stenting following
canalicular trauma or surgery, or to dilate chronic stenosis of the punctum or
canaliculus. Monocanalicular systems are available, but bicanalicular intubation
is generally more stable and is particularly suitable for disease involving both
the upper and the lower punctae or canaliculae. Bicanalicular intubation can be
accomplished by intubating the entire lacrimal outflow system into the nose, or
more simply by intubating the canalicular system alone using a pigtail probe. To
use the pigtail probe to pass and fixate a segment of silicone tubing, the
silicone tube is passed using a monofilament suture. A pre-swedged silicone tube
segment on a monofilament suture has been designed to simplify the process of
pigtail probe intubation of the canalicular system.
PMID- 9760617
TI - Monomanual pupil stretcher.
AB - The monomanual pupil stretcher is a new instrument that allows the authors to
easily, quickly, and safely stretch the pupil. The specific features of the hooks
allow pupil stretching to be performed in a single maneuver and in a more
effective manner.
PMID- 9760618
TI - Hook and loop fastener on loose prisms assists in measuring ocular deviation.
AB - It is difficult to hold a pair of loose prisms in one hand. Doing so can lead to
inaccuracy, which worsens with large-angle exotropia or vertical deviations. The
authors applied a self-adhesive hooked Velcro (Velcro Sticky Back Tape, Velcro
USA Inc., Manchester, NH) strip to the base and the top of loose prisms. They
applied the complementary looped Velcro to a wooden bar. As a result, a pair of
prisms could be suspended horizontally and/or vertically while being held in one
hand. Forty consecutive patients undergoing strabismus surgery without adjustable
sutures were retrospectively studied to evaluate the accuracy of this method.
Clinical use confirmed its ease and convenience. Of 19 patients with exotropia
and 15 patients with esotropia (mean ages 41.9 and 15.7 years, respectively; mean
deviations 44.7 and 49.8 D, respectively), 4 patients with abducens paralysis,
and 2 patients with trochlear palsies, 1 surgery achieved less than 10 D of
residual deviation in all but 2 (5.9%). This simple, inexpensive system can
assist with the clinical evaluation of ocular deviation.
PMID- 9760619
TI - Conjunctival necrosis following the administration of subconjunctival
corticosteroid.
PMID- 9760620
TI - Influence of prosodic boundaries on comprehension of spoken English sentences.
AB - Three experiments investigated the role of prosody in the comprehension of
auditory sentences. In Exp. 1 an analysis of three novice talkers and one expert
talker verified the production parameters of one type of syntactic ambiguity and
showed that pitch cues were more prominent than duration cues. In Exp. 2, 16
listeners used prosodic information to make consistent decisions reliably about
phrase boundaries. In Exp. 3, 40 participants listened to sentences in which
prosody was inconsistent with later morphosyntactic information, indicated their
understanding, and then judged whether a visual target was related to the meaning
of the sentence. Inconsistent prosody slowed comprehension and contributed to
slower, less accurate judgments of sentence meaning. This suggests that prosodic
information contributes to the perception of spoken language and can affect
comprehension even when the syntactic structure indicated by prosody is
contradicted by subsequent morphosyntactic information.
PMID- 9760621
TI - Spatial ability in children's play with Lego blocks.
AB - Sex differences in spatial ability have been argued to originate from sex
differences in children's play preferences. Child (30 boys and 20 girls) were
asked to construct a specific three-dimensional model using Lego blocks and were
also given the Shepard and Metzler test of mental rotation. Those who completed
the Lego model scored significantly higher in spatial ability than those who did
not. Constructional ability was also related to errors made during the
construction of the model, but spatial ability was the best predictor of
completion of the model.
PMID- 9760622
TI - An examination of Shneidman's application of Henry Murray's classification of
needs to suicidal individuals.
AB - 30 suicidal deaths were examined for the presence of needs described by Henry
Murray. The most common needs identified were harmavoidance and infavoidance.
Other needs were present rarely and typically only in unusual suicides such as
double suicides or seppuku.
PMID- 9760623
TI - Verbal contextual generalization in children with and without learning
disabilities.
AB - Braine's (1963) model of language development emphasizes the use of auditory or
temporal processing so verbal contextual generalization can be produced. Recent
literature on auditory or temporal processing skills of children with learning
disabilities led to the prediction that these children would find it much more
difficult to generalize contextually than would children without learning
disabilities. The present study did not support this prediction. The implications
were discussed in view of research on auditory or temporal processing skills of
children with learning disabilities.
PMID- 9760624
TI - The sex ratio, suicide, and homicide in nations of the world.
AB - In a sample of 70 nations in 1980, those nations with higher proportion of males
relative to females were less developed.
PMID- 9760625
TI - Difficulty of a spatial task and sex difference in gains from practice.
AB - The influence of practice on a difficult spatial task in a small sample of 11 men
and 16 women was investigated. Participants were tested on a rotated embedded
figures task modified from the Gottschaldt Hidden Figure Test prior to being
given practice in identifying rotated and nonrotated embedded figures. One week
after the pretest and practice session, the posttest was given. In the small
sample studied, the number of correctly identified rotated figures on the
posttest was significantly increased relative to pretest scores for men and
women. However, the tendency for women to score higher than men after practice
was not significant.
PMID- 9760626
TI - SPECT (HMPAO) support for activation of the medial prefrontal cortices during toe
graphaesthesia.
AB - This experiment was designed to test the construct validity of psychometric
analyses that suggested a strong functional association between the accuracy for
toe graphaesthesia and selective activation of neurons within the medial
prefrontal regions. Single Photon Emission Computerized Tomography (SPECT)
profiles were obtained for three volunteers (2 men, 1 woman) after they had been
exposed to a toe graphaesthesia task or had been exposed to the control setting.
The two measurements for each participant were separated by at least one week.
Qualitative evaluation, using criteria employed for clinical diagnoses, of serial
coronal, sagittal, and horizontal sections clearly indicated a specific increase
in uptake of tracer within the rostral one-third to one-half of the medial
prefrontal cortices of all three subjects during the toe graphaesthesia task
compared to that during baseline conditions. The results are consistent with our
neuropsychological research which indicates that toe graphaesthesia may be an
accurate and useful indicator of the functional integrity of the medial surfaces
of the anterior cerebral hemispheres.
PMID- 9760627
TI - Speech-Sounds Perception Test: analysis of a randomized answer form.
AB - Responses to two forms of the answer sheet for the Speech-Sounds Perception Test,
the standard form and a revised form in which the error types were randomized,
were analyzed for 40 subjects. Although there was a statistically significant
difference between the forms, practically it was negligible.
PMID- 9760628
TI - Locomotion improves children's spatial search: a meta-analytic review.
AB - This meta-analysis quantitatively summarized the developmental influence and the
effects of locomotor experience as well as the benefits of locomotor practice,
locomotor assistance, and active searching patterns on children's search
performance. Based on specific criteria, a search of a database and reference
lists identified 19 studies, including 1,029 children (510 boys and 519 girls)
from 4 to 144 months of age. Outcome measures of spatial performance were
converted to 83 effect sizes that reflected the effects of specific experimental
characteristics. Analyses of variance indicated that with older children,
locomotor activities are more important to their spatial searching. Locomotor
status, searching patterns, locomotor assistance, test conditions, and test
reliability were identified as moderator variables. In addition, locomotor
training significantly improved children's spatial search. The results supported
the hypothesis that children's development of spatial search skills is influenced
by locomotor experience.
PMID- 9760629
TI - Do monkeys choose the more skillful hand in manual problem-solving?
AB - To investigate the relationship between manual skills and hand preference in 4
female Japanese monkeys (Macaca fuscata), the technique of concurrent
investigation of manual skills and hand preference was introduced. 4 female
Japanese monkeys were required to take food out of a pipe using the left hand and
right hand alternately. The performance time and the number of deviations from
alternate sequence were recorded as measure of manual skills and hand preference.
In the result, the preferred hand was not always consistently the skillful one;
however, only one subject tended to choose the more skillful hand in problem
solving, and another subject learned the alternate sequence of reaching. The
performances of two subjects indicated discrimination of both hands in Japanese
monkeys is possible.
PMID- 9760630
TI - Suicide in eminent persons.
AB - A review of several listings of famous historical figures indicated that
percentages of deaths due to suicide ranged from 0.3% to 13.3%, with a median of
2.9%.
PMID- 9760631
TI - Assessment of abilities in basketball: a preliminary study.
AB - Understanding the responding at two competitive levels of sports is prerequisite
for successful identification and selection of the best athletes. The present
study is a preliminary report about scores on 17 cognitive, perceptual, motor,
and psychological measures of 13 elite Greek basketball athletes (national team),
20 to 22 years of age, and 15 children on a national basketball team and 14 to 15
years of age. Longitudinal studies must be conducted for the identification of
the relationships among these measures and basketball performance and the
development of a model for selection of athletes.
PMID- 9760632
TI - Visuoperceptual speed of karate practitioners at three levels of skill.
AB - The Identical Pictures Test was administered to 50 male and 45 female volunteer
karateka who were classified by Fitts' level of learning and karate belt-rank
color system (kyu-dan) into three groups. A 2 (sex) x 3 (skill) analysis of
variance gave a significant difference for skill and sex. Over-all, the
practitioners in the autonomous stage (black belts) and the women had faster
visuoperceptual speed.
PMID- 9760633
TI - Dissociation between specific personal episodes and other aspects of remote
memory in a patient with hippocampal amnesia.
AB - In this paper, we describe some features of remote memory in a single-case, Y.K.,
with amnesic syndrome. His ability to access remote memory was investigated
through a variety of tests and then analyzed in terms of specific aspects of
remote memory, i.e., public events, personal semantic memory, and specific
personal episodes. Although Y.K. showed relatively good performance in recalling
public events, personal semantic memory, and general personal events, he was not
able to recall specific personal episodes over his entire life span. That is,
there appears a clear dissociation between recalling specific personal episodes
and other aspects of remote memory. This suggests he lacks "richness" in his
remote memory, which is probably necessary to maintain one's own identity.
PMID- 9760634
TI - Body perceptions of bulimic and nonbulimic groups.
AB - A brief survey measuring satisfaction with the body, concern for physical
appearance, and motivations for selection of clothing was administered to 30
women in a university-sponsored support group for bulimic students and 30 women
randomly selected from a college campus. No mean differences were found between
the groups on concern for physical appearance when in a social setting, but mean
differences were significant on satisfaction with weight, satisfaction with body
image, and concern for physical appearance when alone.
PMID- 9760635
TI - Reliability of two measures of health-related quality of life in patients with
multiple sclerosis.
AB - Multiple sclerosis is a chronic neurological disease which can cause a variety of
symptoms (motor and sensory impairment, visual problems, bladder and bowel
problems, sexual dysfunction, and decline in cognitive function). Both the
Medical Outcome Study Short Form-36, a generic questionnaire regarding health
related quality of life, and the Disability and Impact Profile, a similar
questionnaire developed for people with chronic diseases, are used regularly to
assess patients with multiple sclerosis. Over a 6-mo. interval 187 patients with
multiple sclerosis completed these questionnaires twice. Internal consistency of
both questionnaires at Times 1 and 2 was .60 or above for all eight scales of the
Medical Outcome Study Short Form-36 and five scales of the Disability and Impact
Profile. Estimates of test-retest reliability for three scales of the Medical
Outcome Study Short Form-36 were below .60, but for all scales of the Disability
and Impact Profile were .60 or higher. The two questionnaires appeared to be
reliable for our sample of patients with multiple sclerosis.
PMID- 9760636
TI - Life satisfaction, suicide, and homicide.
AB - In 1985 in 18 nations measures of life satisfaction in college students were not
associated with the suicide and homicide rates of 15- to 24-yr.-olds.
PMID- 9760637
TI - Men and women holding hands: whose hand is uppermost?
AB - This study explored the issue of whether status and power differences are
expressed in the way men and women hold hands. It was hypothesized that men's
hands would be upper in heterosexual handholding couples significantly more often
than women's. Also, to explore the possibility that height differences of
handholding partners might affect handholding position, all handholding couples
observed in this study were classified as couples with men and women of equal
height or couples where either the men or women were taller. A total of 1,006
handholing couples were observed, and men's hands were significantly more likely
to be the upper one in couples when men were taller than women and in couples
where men and women were of equal height, suggesting that, while height does
matter, it is less important for this handholding pattern than sex differences.
PMID- 9760638
TI - Reinterpreting telepathy as unusual experiences of empathy and charisma.
AB - Telepathy is often dismissed because it is judged to be contrary to the accepted
facts of social psychology. This article argues that what is called telepathy may
require nothing more than empathy and charisma and is reducible to these
sociopsychological constructs. Two studies explore this hypothesis. In the first
the proposed relationship is used to explain the sheep-goat effect. In the second
study scores on charisma and empathy are used as direct predictors of telepathy
scores. The results in combination support the interpretation of telepathy as
phenomenologically impressive social psychological events which in less dramatic
instances are termed empathy and charisma.
PMID- 9760639
TI - Effect of different quantities of variable practice on acquisition, retention,
and transfer of an applied motor skill.
AB - This investigation examined the effect of manipulating different quantities of
variable practice in the acquisition phase on the retention and transfer
performance of a dart throw. Participants in the Specific condition practiced a
total of 75 acquisition trials from a distance of 2.39 m. Participants in the
Specific + Variable condition practiced a total of 75 acquisition trials with 25
trials from distances of 1.47 m, 2.39 m, and 3.30 m. Participants in the Specific
+ Varplus condition practiced a total of 75 acquisition trials with 15 trials
from distances of 1.47 m, 1.93 m, 2.39 m, 2.84 m, and 3.30 m. Results of the one
way analysis of variance on the 24-hr. retention test from 2.39 m yielded no
significant differences among practice conditions for mean radial error. A one
way analysis of variance on the 24-hr. transfer test from 3.76 m indicated that
the Specific + Variable and Specific + Varplus conditions performed with
significantly smaller mean radial error than the Specific condition. The results
are discussed in regard to recent research and applicability to instructional
settings.
PMID- 9760640
TI - Effect of warning on feigned malingering on the WAIS-R in college samples.
AB - Research indicates claimant malingering of cognitive deficits to be common in
personal injury litigation. Efforts have been made to either detect such
tendencies or deter efforts at malingering. The present study examined whether
warning people that feigned malingering efforts would be detected results in more
valid profiles on the Wechsler Adult Intelligence Scale-Revised. Undergraduates
(N = 48) were randomly assigned to one of three conditions: feigned malingerers
without warning, feigned malingerers with warning, and controls. Analysis
indicated both feigned malingerer groups performed significantly worse than the
control group; however, feigned malingerers with warning did not perform
significantly better than those without warning. Unlike previous research using
the Wechsler Memory Scale-Revised, results did not support effectiveness of
warning in reducing feigned malingering scores.
PMID- 9760641
TI - Self-concept of academic ability as a function of sex, age, and academic
achievement among African adolescents.
AB - This study examined (a) sex and age variations for scores on Self-concept of
Academic Ability and academic achievement among 244 African adolescents attending
a coeducational high school and (b) correlations between scores on Self-concept
of Academic Ability and academic achievement by sex and age. No significant sex
differences were found, but there were significant age differences on the Self
concept scores and measures of English, science, and history but not in
mathematics. A significant positive correlation was found between Self-concept
scores and academic achievement for boys and girls and in all age groups, but the
magnitude of the correlations with achievement in mathematics was stronger among
boys than among girls.
PMID- 9760642
TI - The use of long guns for murder.
AB - In 1980, long guns were used relatively more often for murder in states which
were more rural and which had a greater proportion of hunters.
PMID- 9760643
TI - Time course analysis of the reverse-Stroop effect in Japanese Kanji.
AB - A reverse of the Stroop effect was obtained with Japanese kanji (logographic
script) but not with Japanese kana (syllabic scripts) by Morikawa in 1981. In the
present study, the normal effect on reaction times by word and color was altered
by presenting the words before or after the color. The reverse Stroop effect was
observed with kanji but not with kana even when the color was presented prior to
the word. It was shown that the difference between kanji and kana in the reverse
Stroop effect could not be explained by the relative speed of processing of word
and color and that the reading process of kanji is different from that of kana.
PMID- 9760644
TI - Selective effects of physical exercise on choice reaction processes.
AB - The aim of the present study was to examine the effects of an exercise of
moderate intensity (60% of maximal aerobic power) on specific information
processing mechanisms. 22 students completed 3 10-min. exercise bouts on a
bicycle ergometer. Concomitantly, participants performed six manual-choice
reaction tasks manipulating task variables (Signal Intensity, Stimulus-Response
Compatibility, and Time Uncertainty) on two levels. Reaction tests, randomly
ordered, were administered at rest and during exercise. A significant
underadditive interaction between Time Uncertainty and exercise was found for the
highest quartiles of the distribution of reaction times. No other interaction
effects were obtained for the other variables. These results reasonably support
that moderate aerobic exercise showed selective rather than general influences on
information processing.
PMID- 9760645
TI - Variation of suicide and homicide rates by longitude and latitude.
AB - State suicide rates in 1980 varied gradually, rather than abruptly, with
longitude, as did homicide rates with latitude.
PMID- 9760646
TI - Some relationships between skills in word-category recall and factors in adults'
aphasia.
AB - It has long been recognized that a basic dimension to the lexical organization of
the brain is semantic, and some brain mapping studies have indicated that the
brain fields are distinctly different from some grammatical classes. Findings
from the present investigation showed consistent relationships between 29 aphasic
adults' performances on tasks involving graphic and gestural skills and those
involving sequential recall of spoken words from different word categories. Each
adult received the Porch Index of Communication Abilities which relies upon the
physical manipulation of objects to assess verbal, gestural, and graphic
abilities. Scores on a test requiring recall of word strings of nouns, verbs,
adverbs, adjectives, or prepositions were used to predict the subscale scores
from the Graphic and Gestural factors of the index. Recall scores for verb and
preposition were predictive of the aphasic subjects' performances on the Graphic
subscale, and noun and preposition scores were predictors of subjects' scores on
the Gestural subscale. The results are related to other research showing that
verb and preposition skills are predictive of fine motor abilities of children
with communication disorders and brain-mapping studies. Some discussion centers
on possible overlapping functions of brain activity involving word categories,
language, and fine motor skills.
PMID- 9760647
TI - Sleep in relation to age, sex, and chronotype in Japanese workers.
AB - The Morningness-Eveningness Questionnaire and Life Habits Inventory were
administered to 622 Japanese workers matched for sex and age. We investigated the
distributions of the scores on the Morningness-Eveningness Questionnaire and
sleep-wake habits by age and sex. Subjects were classified into five age groups
and three chronotypes. The distributions and mean scores on the questionnaire
advanced slightly toward the Morning type from the young to the aged group. The
habitual bedtimes and waking times were significantly earlier in all the
chronotypes from the young to the aged group, and the preferred bedtimes and
waking times were also clearly earlier from the young to the aged group. The
length of sleep was shorter for the Evening than the Morning types, especially in
the group below 24 yr. The differences in habitual and preferred sleep length
were greater than 1 hour for all age groups, especially the two groups under 34
yr. The number of awakenings during night sleep increased from the young to the
aged group for all chronotypes. The older Evening type tended more toward
frequent napping and longer naptime. The variabilities of bedtime and sleep
length were larger for the young and Evening type than for the old group and
Morning types. Further, the mood upon waking and satisfaction with sleep length
were better in the aged Evening type than the young Morning type. The women under
44 yr. woke up earlier than the men of the same age, and the women of the 35-54
yr. groups had a shorter length of sleep than others. These may be related to
childcare and housework. These results indicated that the phase of circadian
rhythms had moved forward from the young to the aged group, and the individual's
rhythm, of those that were aged Morning types, showed better agreement with sleep
wake rhythms than did others.
PMID- 9760648
TI - Numbers of details in the reconstruction of an emotional narrative decrease
linearly as a function of time.
AB - 33 university students listened to a 5-min. ambiguous narrative about a young boy
(The Billy Story) while another 33 students did not. At the end of the final
examination for the course the students were promised a 2% bonus mark if they
could reconstruct the details of the story. Whereas only one student who heard
the story could not recall any details, 30% of the students (n = 9) who never
heard the story generated a false one. The numbers of accurate details recalled
by those who heard the story decreased linearly with the time (5 through 30
days). Five times the numbers of the women than men who heard the story
attributed the young boy's anomalous experience to sexual abuse.
PMID- 9760649
TI - Stress triggers of long, short, and variable sleep patterns.
AB - Sleep and stress patterns in 34 young adult sleepers were measured. Time series
analysis of sleep report measured 6- and 3-day patterns of light stress preceding
a change in sleep pattern for long (n = 15) and short or variable (n = 7 and 12)
sleepers, respectively.
PMID- 9760650
TI - Human classical conditioning of visual compound stimuli in paired-associate
tasks.
AB - College students in introductory psychology participated in four experiments to
investigate the salience of color versus figure elements of paired associates.
The study also reviewed the process of learning paired associates within the
context of first-order simultaneous classical conditioning. In Exp. 1, four
separate classes received different treatments concerning the position and type
of stimulus element (color of figure) they were instructed to recall. There were
seven trials with a 30-min. delay between the sixth and seventh trials. The
results indicated that the groups who were required to remember the figure
element of the pairs, significantly out-performed the color groups and also
learned the pairs much faster. Also, there was a sharp rise in mean correct
responses remembered after a 30-min. delay for the group required to recall the
color element of the paired associates. Exp. 2 was a within-subjects comparison
of the effectiveness of the color and figure elements as stimuli. Again, the
figures elicited more correct responses than colors. Exp. 3 tested the
effectiveness within subjects of the stimulus elements as response factors. As
responses, however, there were no significant differences in the number of
correct answers when recalling color or figure elements until the 30-min. delay
between Trials 6 and 7. As expected in Exp. 4, figures elicited significantly
more functional descriptions than did colors, suggesting that figures possess a
logographic nature which acts as a mnemonic device aiding in the memory of
stimuli and responses.
PMID- 9760651
TI - Joseph Richman's signs for distinguishing genuine from simulated suicide notes.
AB - Scores from two independent judges indicated that criteria derived from the
clinical experience of a suicidologist were successful in differentiating genuine
from simulated suicide notes.
PMID- 9760652
TI - Order of item difficulty on the WAIS-R picture arrangement subtest: data from a
traumatically brain-injured sample.
AB - Although the items within the WAIS-R subtests are presumed to be in ascending
order of difficulty, several studies have indicated that the Picture Arrangement
subtest items are out of order for clinical groups. The present study
retrospectively examined item difficulty and discrimination in the test data of
74 individuals who had been referred for neuropsychological assessment following
a traumatic brain injury. While results were not statistically significant,
qualitative analysis of partial credit scoring for four of the items indicated
some inconsistencies in the scoring rationale. Caution is recommended in the use
and interpretation of the Picture Arrangement tests scores in the assessment of
individuals with traumatic brain injury.
PMID- 9760653
TI - Revising and validating the random search model for competitive search.
AB - A random search model was fit to a total of 2592 visual search times on a single
target detection task. By using a competing homogeneous background and uniform
stimulus material, specifying viewing distance, controlling the presentation of
search task material, and eliminating some options for extreme search strategies,
very high correlation coefficients were found when a random search model was fit
to both the individual data and to pooled data. A response time parameter was
incorporated into the traditional random-search model and very good predictions
of search performance were obtained.
PMID- 9760654
TI - Clinical aspects associated with adjustment in unusual sleepers.
AB - Sleep behavior and self-reported adjustment of 93 young adult sleepers were
measured. The 34 unusual sleepers (short, long or variable) differed in
adjustment from controls. 7 short sleepers reported more intense, worrisome
responses than other unusual sleepers and controls.
PMID- 9760655
TI - Word-type effects in word-stem priming: evidence for semantic processing in the
perceptual representation system?
AB - While a presemantic Perceptual Representation System is believed to mediate
implicit memory tasks such as word-stem priming, clinical studies suggest
semantic information can be processed during priming. To clarify the nature of
this system, we investigated word-type effects in word-stem priming in a
nonclinical sample of 41 undergraduates who rated the pleasantness of threatening
and nonthreatening words, performed implicit and explicit memory tasks, and
completed measures of mood state. More nonthreatening words were primed and
scores on the Beck Depression Inventory were negatively correlated with
production of nonthreatening words. During cued recall, more threatening than
nonthreatening words were remembered and ratings of state anxiety were negatively
correlated with recall of nonthreatening words. Our findings support the
contention that semantic information is processed during priming and that mood
congruent biases also operate. These results may call for a reconceptualization
of the Perceptual Representation System.
PMID- 9760656
TI - Correlations between two Multidimensional Anxiety Scales for Children.
AB - The correlation between scores on two new anxiety questionnaires for children (ns
= 54 boys, 54 girls), the Screen for Child Anxiety Related Emotional Disorders
and the Multidimensional Anxiety Scale for Children was .72, with values for
subtests ranging between .35 and .63.
PMID- 9760657
TI - Vividness of visual and haptic imagery of movement.
AB - This study investigated the relationships between visual and haptic imagery of
movement. A total of 338 subjects, all university students aged between 18 and 26
years, completed the Vividness of Movement Imagery Questionnaire, which evaluates
capacity for visual imaging, and a modification of this questionnaire, the
Vividness of Haptic Movement Imagery Questionnaire, designed to evaluate capacity
for haptic imaging. Scores on the two questionnaires were significantly
correlated .60.
PMID- 9760658
TI - Color or brightness effects on grip strength?
AB - Research into the effects of color on grip strength has produced inconsistent
results, but studies show methodological problems, for example, the non
standardised reporting of stimulus colours, differing intertrial rests, and the
neglect of warm-up effects. The present study was designed to replicate the 1989
work by Hasson, et al. and also to examine potential brightness effects of
stimuli on grip strength. Analysis indicated brightness effects might confound
potential to produce Type I errors.
PMID- 9760659
TI - Defense Mechanism Test and electrodermal activity.
AB - Electrodermal activity was registered during examination with the Defense
Mechanism Test of 21 patients diagnosed with anxiety disorder, affective
disorder, or schizophrenic disorder. The test can be interpreted as a model
situation of how a person defends himself against a threat to avoid anxiety. We
used Andersson's modified version of the test and tested the hypothesis that
electrodermal activity should increase when there were responses categorised as
Anxiety and decrease when there were responses categorised as defences or when
the threat was correctly identified. We found significant increase in all
electrodermal variables in connection with responses categorised as Anxiety.
After exposures with responses categorised as Isolation, the maximal skin
conductance level and the magnitude of late nonspecific responses were
significantly decreased. After exposures when the threat was identified and thus
no longer subliminal, the electrodermal activity was significantly decreased. All
these findings support our hypothesis. After exposures with significantly
decreased. All these findings support our hypothesis. After exposures with
responses categorised as Denial all electrodermal variables were significantly
increased. Similarly in responses categorised as Repression, Introaggression, and
Disavowal or denial of hero's sex the frequency of late nonspecific responses
were significantly increased. The increased electrodermal activity could be due
to insufficient defence strategies as categorised in the Defense Mechanism Test.
PMID- 9760660
TI - Attitude towards aggression and creative functioning in patients with breast
cancer.
AB - Three projective personality tests were used to assess attitude to aggression
(The Identification Test), anxiety and defenses (The Meta-Contrast Technique) and
creative functioning (The Creative Functioning Test) in 70 patients with breast
cancer. Discriminant analyses were applied pro primo to characterize
psychologically patients with a better prognosis and patients with a poorer
prognosis. A second aim was to characterize psychologically older
(postmenopausal) and younger (premenopausal) women. Generally, high scores on the
Identification Test indicated maladaptive attitudes towards aggression among all
the patients. Patients with a poorer prognosis showed responses that in healthy
subjects indicate acknowledgement of aggressive impulses, perhaps suggesting lack
of "defenses" against such impulses among those patients. Another way to describe
it would be that patients with a better prognosis seem to have (normally
nonadaptive) "defenses" against aggressive impulses while those with poorer
prognosis have not. Surprisingly, the patients with a better prognosis (but not
those with a poorer prognosis) gave responses classified as depression in the
Meta-Contrast Technique. Typical of premenopausal patients were responses
classified as anxiety as well as reaction formation on the Identification Test.
Responses classified as adaptive defenses (isolation) were seen in the Meta
Contrast Technique. A surprising finding was that many of these patients were
characterized by high scores on the creativity test. These original statistically
significant findings of attitudes towards aggression and creative functioning in
breast cancer patients are discussed in relation to the underlying nature of
aggression and creativity.
PMID- 9760661
TI - Anticipatory cues can interfere with inhibitory operant behavior in the rat.
AB - In four separate experiments a total of 24 male rats were trained for 30 min.
daily in the same temporal order to inhibit their responses for at least 6 sec.
before a response-contingent reward was delivered (DRL-6 sec.). The rats tested
as the second group each day displayed about twice the number of errors (effect
size = 40%) shown by rats tested in the first or third groups. These results
suggest that anticipatory cues, acquired within two sessions, interfere with
response inhibition during an appetitive task for a limited time (between a few
minutes to about one hour). The results are consistent with the hypothesis that
learned anticipation of reward may decrease inhibitory mechanisms by facilitating
limbic lability.
PMID- 9760662
TI - Preliminary study on the effect of rocking on activities of persons with severe
mental and physical handicaps.
AB - In this preliminary observation, a group of seven mentally and physically
handicapped persons of chronological ages ranging from 15.4 yr. to 26.8 yr.
experienced 15 sec. of physical rocking. For the further analysis, the
poststimulus periods were classified into either those when the subjects'
spontaneous head, mouth, and body movements had increased from the prestimulus
period or those decreased. The median heart rates recorded in the poststimulus
period were not significantly different from those in the prestimulus period on
trials on which there was an observable increase in the rates of spontaneous
head, mouth, and body movements; however, the median heart rates decreased during
those trials on which a decrease in the rates of the movements occurred. Since it
is said that rocking heightens arousal of persons with mental and physical
handicaps, it is suggested that spontaneously emitted, aimless head, mouth, and
body movements attributed to low arousal were reduced by heightened arousal
rather than by a decline in participants' activities.
PMID- 9760663
TI - Reply to Greenberg's critique of Malik, et al.'s experiment on the method of
subliminal psychodynamic activation.
AB - Greenberg raised two issues concerning an experiment reported by Malik, et al. on
the method of subliminal psychodynamic activation. One relates to the
appropriateness of control and threshold stimuli and the other to the use of
subjective thresholds. Both concerns are addressed.
PMID- 9760664
TI - Perceptions of the heart-rate guide.
AB - Preliminary assessment was made concerning perceptions of the newly developed
heart-rate guide, devised as an educational tool to promote physical activity.
Unlike the traditional target heart-rate chart, the heart-rate guide illustrates
the value of low to moderate intensity physical activity. Following a brief
lecture about the Surgeon General's report on physical activity and health and
the usefulness of heart-rate charts and guides, 120 college students (M age 21.5
+/- 2.8 yr.) completed a self-report survey consisting of statements regarding
their use of target heart rates during exercise and their perceptions of the new
heart-rate guide as compared to the traditional heart-rate chart. 83% of the
subjects reported that the new guide better illustrated the findings from the
Surgeon General's report, 5% reported no difference between the guide and the
chart, and 12% reported that the chart better illustrated the report's findings
(p < .01). 48% never measure their heart rates when they exercise, 48% sometimes
measure their heart rates and 4% always do so (p < .01). While the new guide
should not replace the traditional chart, these results suggest that college
students perceive the heart-rate guide as a useful tool despite the fact that
only a small percentage of students regularly measure their heart rates when they
exercise.
PMID- 9760665
TI - Heights of U.S. Presidents: a trend analysis for 1948-1996.
AB - A Mann Trend Test yielded a trend in increased height for 10 U.S. Presidents from
1948-1996, consistent with previous findings that height is a heuristic for
dominance.
PMID- 9760666
TI - Short-term memory for faces: ageing and the serial position effect.
AB - Properties of short-term memory for faces (Exp. 1) were investigated in 40 young
and 30 elderly persons and compared with short-term memory for non-verbal shapes
(Exp. 2) with 30 new persons in a young group and an elderly one. Young subjects
displayed a U-shaped curve for both kinds of stimuli, and elderly subjects
displayed a U-shaped curve, but the recency effect was abolished for faces (in
one condition). This suggests a possible specific short-term store for faces.
PMID- 9760667
TI - Spiral maze performance in dementia.
AB - 58 patients with probable Alzheimer dementia and 58 with probable multi-infarct
dementia were given spiral mazes of differing complexity and 20 other
neuropsychological tests. When age and over-all neuropsychological functioning
were taken into account, spiral maze performance was poorer for patients with
multi-infarct dementia but there were no significant group differences related to
task complexity or indices of performance strategy.
PMID- 9760668
TI - Effects of melatonin in two individuals with Alzheimer's disease.
AB - Dementia has been associated with circadian rhythm disturbances expressed in
several dimensions including body temperature, hormonal concentrations, sleep and
wakefulness patterns, and rest-activity cycles. These disturbances may be the
result of a dampening in the amplitude of the circadian rhythm. One of the
symptoms associated with the aging process has been a decline in the amplitude of
the melatonin rhythm. Here, the results of melatonin administration to two
patients with Alzheimer's disease are presented. Melatonin administration
enhanced and stabilized the circadian rest-activity rhythm in one of the patients
along with some reduction of daytime sleepiness and an improvement in mood. The
other patient, who was characterized by less cognitive impairment, showed no
significant changes associated with melatonin ingestion. Interestingly, the
acrophase of rest-activity was delayed for about one hour in both patients. These
results suggest that melatonin may have beneficial effects in some patients with
Alzheimer's disease.
PMID- 9760669
TI - Threshold effect in visual perception of geometrical figures.
AB - Filtering of the input image has been shown to play a central role in several
aspects of visual perception. In our experiments in visual perception of the area
of geometrical figures the orientation in random dot patterns, and some visual
illusions, we have shown that a threshold effect inferred from the filtering of
the input image produces a perceptual error. This error has been explained by
using the concept of Image Function. The present paper is a brief review of our
experimental results and of the models we have proposed.
PMID- 9760670
TI - Self-esteem and injury in competitive field hockey players.
AB - A volunteer sample of 50 competitive field hockey players completed the
Coopersmith Self-esteem Inventory at pre- and postseason and prospectively
collected injury data over a 20-wk. season. Multiple regression analysis showed
no relationship between scores on Self-esteem and the number of injuries, the
participation time affected due to injury, and sex of players. Further multiple
regression analysis showed that frequency of the more severe injuries
significantly predicted scores on Self-esteem. This finding can be interpreted as
evidence of the relationship between low self-esteem and injury in sport.
PMID- 9760672
TI - Steven Stack's ecological studies of national suicide rates.
AB - The results of eight studies by Steven Stack on national suicide rates were
replicated using a data set for 1980; however, a multivariate data analysis
indicated that the many associations found by Stack reduced to one major
correlate of national suicide rates--females' participation in the labor force.
PMID- 9760671
TI - Effects of three stimulus parameters on eye position in cerebral palsied adults.
AB - Bilateral eye position was measured in 6 cerebral palsied adults to assess the
effects of stimulus dimensions (horizontal, vertical), amplitude (+/- 4 degrees,
+/- 6 degrees, +/- 8 degrees), and frequency (0.3, 0.5, 0.7 Hz) on saccadic and
pursuit movements. The head-free, corneal reflection method was used for 54 10
sec. trials of square, triangle, and sine wave stimuli. Shared variance between
each eye's position and the stimulus was tested by Wilcoxon T (dimension) and
Friedman analysis of variance (amplitude, frequency) showing that the effects of
saccadic and pursuit dimension and amplitude were individualized with regard to
subject and right and left eye positions. The bilateral eye position of 5 of 6
subjects was affected by saccadic frequency; pursuit frequency affected bilateral
eye position of 4 of 6 subjects. The lowest shared variance (critical difference
in ranks) was at 0.7 Hz. The results are discussed with regard to subjects'
disability, stimulus velocity, and frequency of directional reversal. Reversal
may be the most critical stimulus property.
PMID- 9760673
TI - Stroop interference is the result of comparable, not of differential processing
speeds of two stimulus dimensions.
AB - On a digit-counting Stroop task, processing of the slower, nonverbal, i.e.,
number, dimension was slowed further by a large-number set (6 to 9), as compared
with a small-number set (1 to 4). In the task, neutral symbols or conflicting
digits were arranged on a horizontal line (e.g.,@@, 444) and on two separate
sheets. Each sheet contained 120 stimulus arrays. Subjects counted out loud the
number of symbols or digits in each array, and their counting times for each
sheet were recorded. 23 subjects received the small-number set while 21 received
the large-number set. It was found that counting a large number of symbols took
significantly longer time (by 162 sec. per 120 stimulus arrays) than counting a
small number of symbols. Moreover, interference was nonexistent (2 msec. per
stimulus array) when a large number of conflicting digits were counted but was of
a typical magnitude (110 msec. per stimulus array) when a small number of
conflicting digits were counted. This suggests that Stroop interference is better
explained as the result of comparable, not of differential, processing speeds of
the two stimulus dimensions. Implications for the cause and the locus of Stroop
interference are discussed.
PMID- 9760674
TI - Renin inhibitors.
PMID- 9760675
TI - The discovery and development of angiotensin II antagonists.
PMID- 9760676
TI - Development of an orally active tripeptide arginal thrombin inhibitor.
PMID- 9760677
TI - Discovery and development of an endothelin A receptor-selective antagonist PD
156707.
AB - PD 156707 is a highly potent, selective antagonist of the ETA receptor that has
demonstrated efficacy in a number of different disease models. The next few years
will be exciting in the field of ET research as several compounds progress
through clinical development. It is our hope that the efficacy that data
demonstrated to date with PD 156707 will some day be translated into real hope
for the patients who are waiting beyond the confines of our research
laboratories.
PMID- 9760678
TI - Endothelin receptor antagonists.
PMID- 9760679
TI - LHRH antagonists.
AB - After almost two decades, the research on LHRH antagonists has produced a number
of decapeptides that are currently in clinical studies. The structures of these
antagonists, unlike the agonists, differ substantially from that of LHRH. Five of
the ten amino acids are unnatural and of D configuration. The structural
combination of a hydrophobic N-terminus (residues 1, 2, and 3) and a
basic/hydrophilic C-terminus (residues 6 and 8) was thought to be responsible for
some HR reactions encountered with the second generation of LHRH antagonists.
This side effect was greatly reduced by substituting the appropriate combination
of amino acids at positions 5, 6, and 8. The next hurdle in the drug development
of LHRH antagonists was solubility and aggregation. In the case of A-75998, water
solubility was improved by 12- to 25-fold via substitution of NMeTyr at position
5. However, based on DLS analysis, the aqueous solutions still contained some
large aggregates that were not visible to the naked eye. This formation of
aggregates was eliminated on formulating A-75998 in Encapsin. In men, a single
s.c. dose of 2 mg of A-75998 suppressed T to the castrate levels for over 30 hr.
Other LHRH antagonists including ganirelix and cetrorelix are also in phase I/II
clinical studies. Clinical studies with cetrorelix in prostate cancer; in vitro
fertilization, and benign prostate hypotrophy have been reported.
PMID- 9760680
TI - LHRH agonists.
PMID- 9760681
TI - Discovery and development of somatostatin agonists.
PMID- 9760682
TI - Factors impacting the delivery of therapeutic levels of pyrone-based HIV protease
inhibitors.
PMID- 9760683
TI - The integration of medicinal chemistry, drug metabolism, and pharmaceutical
research and development in drug discovery and development. The story of
Crixivan, an HIV protease inhibitor.
PMID- 9760684
TI - De novo design and discovery of cyclic HIV protease inhibitors capable of
displacing the active-site structural water molecule.
PMID- 9760685
TI - Discovery and development of the BHAP nonnucleoside reverse transcriptase
inhibitor delavirdine mesylate.
PMID- 9760686
TI - Famciclovir. Discovery and development of a novel antiherpesvirus agent.
PMID- 9760687
TI - The use of esters as prodrugs for oral delivery of beta-lactam antibiotics.
AB - It is apparent that the sequence of events that has been followed in the approach
to the discovery and development of a new beta-lactam prodrug has been similar in
many of the case histories we have studied and indeed similar to the approach we
have followed. Initially, we select a suitable series of prodrug moieties, which
either comprises totally novel structures or is deduced from the data bases
available (bearing in mind reports of potential toxicity) or both. The successful
preparation of these prodrugs and the studies undertaken to ensure they are of
known purity and stability is not easy and, as would be expected, is the initial
go/no-go decision. Usually, the next stage has involved the assessment of whether
or not bioavailability of the parent molecule is increased after administration
of the prodrug ester by gavage to laboratory animal species. The selection of
which species to use has very often been made according to which has the most
information available in those particular laboratories and in the literature. It
is this process that can be dishearteningly misleading as was demonstrated in
Table IV and Fig. 1. Increasing the range of animal species does not lead to a
better ability to predict bioavailability in humans. Hydrolysis studies are
important to ensure that any novel prodrug will hydrolyze in human tissues, and
also in the clarification of why a particular prodrug is not performing as
expected in animals. After selection, it is essential to determine where and how
rapidly hydrolysis takes place in the animal species to be used for safety
evaluation prior to the first bioavailability studies in humans. The assessment
of absolute oral bioavailability has not always been undertaken. This would seem
critical for studies in not only the selected animal species but also in humans.
In the absence of these data it is difficult to judge whether oral uptake can be
increased further by modifying the ester moieties and at the development stage to
determine whether or not modifications in formulation could increase
bioavailability. When the prodrug is being developed for an injectable beta
lactam already available for humans, there would be no problem, but it would be
an important consideration during the development of an entirely novel beta
lactam antibiotic for which no parenteral data are available in humans. Animal
data are not totally predictive. The development of prodrugs is not easy, as a
consequence of species differences in the properties of the prodrug superimposed
on those of the parent compound during the evaluation. However, technical
advances have enabled us to assay concentrations more precisely, determine basic
physicochemical properties more efficiently, understand absorption processes by
the use of in vitro systems, and analyze data far more comprehensively by the use
of ever-evolving computer software. The prodrug approach to increasing the oral
bioavailability of beta-lactam antibiotics has provided clinically valuable
agents and continues. Despite the inherent difficulties, knowledge gained over
the years, of the relationships between physicochemical and biological properties
of the parent compound and the intact prodrug ester, has contributed to the
design of novel prodrugs and a number of novel auxiliaries have been developed.
PMID- 9760688
TI - Hematoregulators. A case history of a novel hematoregulatory peptide, SK&F
107647.
PMID- 9760689
TI - Discovery and development of GG745, a potent inhibitor of both isozymes of 5
alpha-reductase.
PMID- 9760690
TI - Discovery of a potent and selective alpha 1A antagonist. Utilization of a rapid
screening method to obtain pharmacokinetic parameters.
PMID- 9760691
TI - Discovery of bioavailable inhibitors of secretory phospholipase A2.
AB - Substrate-mimetic inhibitors of sPLA2 with submicromolar in vitro potency were
discovered by use of a novel dual substrate screening strategy. In vivo
evaluation of selected inhibitors in the rat carrageenan paw edema model of
inflammation, however, indicated that in vitro potency was not a good predictor
of in vivo activity. Studies of the metabolic stability of early examples of
these inhibitors suggested that the metabolic lability of these compounds was a
major contributing factor to the observed weak in vivo activity. In an attempt to
achieve improved in vivo activity, we prepared and tested compounds designed to
overcome the observed metabolic instability. The design of the new compounds
involved two types of changes in the inhibitor molecules. First, the C-2 ester
moiety was replaced with an amide function so that direct cleavage by stomach
acid and blood esterases at this site was minimized. Second, omega-oxidation of
the decanamide moiety was eliminated by substitution of hydrogen with fluorine in
this position. Compounds containing fluorine in the terminal positions of the
alkyl chain retained sPLA2 inhibitory activity and also possessed improved in
vitro metabolic stability and pharmacokinetic parameters relative to
nonfluorinated inhibitors in this series. As exemplified by GW 4776, improvements
in metabolic stability alone, however, were not sufficient to ensure oral
activity. Thus, GW 4776 did not show oral activity in the carrageenan edema model
and had only modest activity after i.v. dosing in the same model. In fact, the
results for GW 9624 and GW 8219 suggested that factors in addition to potency of
sPLA2 inhibition and metabolism affect the observed in vivo activity. Despite the
fact that these two compounds varied only by a single oxygen-to-sulfur
substitution, one was active whereas the other was not. One possible explanation
for the observed variability is a compound-dependent difference in the rate of
equilibration into tissue. This possibility is relevant as both the carrageenan
paw edema model and the phorbol ester edema model involve a localized
inflammation. No measurements were made to assess differences in the distribution
of the different inhibitors between the blood and the localized site of
inflammation. In summary, a series of bioavailable inhibitors of sPLA2 was
prepared using an iterative approach that combined medicinal chemistry, in vitro
and in vivo evaluation of biological activity, and metabolic and pharmacokinetic
studies. Although some compounds in the series showed in vivo activity, the anti
inflammatory effect observed in animal models was modest and a decision was made
to abandon sPLA2 as a molecular target for the development of anti-inflammatory
agents.
PMID- 9760692
TI - The anxieties of drug discovery and development. CCK-B receptor antagonists.
PMID- 9760693
TI - CI-1015. An orally active CCK-B receptor antagonist with an improved
pharmacokinetic profile.
PMID- 9760694
TI - Orally active nonpeptide CCK-A agonists.
PMID- 9760695
TI - Orally active growth hormone secretagogues.
PMID- 9760696
TI - Dorzolamide, a 40-year wait. From an oral to a topical carbonic anhydrase
inhibitor for the treatment of glaucoma.
AB - Dorzolamide, on the basis of its pharmacological profile and lack of undesirable
side effects in safety assessment studies together with the fact that it could be
formulated in solution at 2%, underwent extensive clinical studies. Early
clinical studies in the development of dorzolamide have been described elsewhere
(Maren, 1995; Serle and Podos, 1995). In a 1-year study in which a comparison was
undertaken in patients for intraocular pressure lowering effects between 2%
dorzolamide administered three times daily, 0.5% betaxolol twice daily, and 0.5%
timolol twice daily, the peak reductions in intraocular pressure were 23, 21, and
25%, respectively. Tachyphylaxis did not develop to dorzolamide nor were
electrolyte and/or systemic side effects encountered (Strahlman et al., 1995).
The latter is consistent with results of a pharmacokinetic study in humans in
which plasma levels of dorzolamide were lower than the limit of detection (5
ng/ml) at a time when the red blood cell content of dorzolamide had reached
steady state which was appreciably less than the red blood cell content of the
enzyme (Biollaz et al., 1995). Patients taking 0.5% timolol twice daily received
either 2% dorzolamide twice daily or 2% pilocarpine four times daily for 6 months
and the additional reductions in intraocular pressure elicited by dorzolamide and
pilocarpine were very similar. However, pilocarpine usage resulted in a higher
discontinuation rate (Strahlman et al., 1996). In a separate study in which
dorzolamide and pilocarpine were compared at these dosage schedules, patients
preferred dorzolamide to pilocarpine by a ratio of over 7 to 1 in terms of
quality of life (Laibovitz et al., 1995). In summary, the quest for a topical,
ocular hypotensive, CA inhibitor, though time-consuming, was a successful one
with the introduction of dorzolamide into general clinical practice.
PMID- 9760697
TI - Discovery and development of novel melanogenic drugs. Melanotan-I and -II.
PMID- 9760698
TI - Experimental strategies to promote axonal regeneration after traumatic central
nervous system injury.
AB - A damage or pathological process that destroys the continuity of axons in the
mature central nervous system (CNS) has devastating consequences and produces
lasting functional deficits. One of the major challenges in this field is to
stimulate the regrowth of severed axons and reconstruction of pathways. Recent
progress in molecular and cell biology has resulted in an explosion of knowledge
on factors in the adult CNS being nonsupportive or even actively inhibitory to
axonal regrowth. The new findings have a strong impact on the development of new
therapeutic concepts directed to stimulate axonal regeneration. They give rise to
cautious optimism, showing that under some circumstances repair of a CNS lesion
is possible. In this review the authors summarize the current knowledge on the
factors and mechanisms involved in regeneration failure and provide an overview
of the current therapeutic approaches that may enable effective CNS regeneration
in the future.
PMID- 9760699
TI - Inflammation and glial responses in ischemic brain lesions.
AB - Focal cerebral ischemia elicits a strong inflammatory response involving early
recruitment of granulocytes and delayed infiltration of ischemic areas and the
boundary zones by T cells and macrophages. Infiltration of hematogenous
leukocytes is facilitated by an upregulation of the cellular adhesion molecules P
selectin, intercellular adhesion molecule-1 and vascular adhesion molecule-1 on
endothelial cells. Blocking of the leukocyte/endothelial cell adhesion process
significantly reduces stroke volume after transient, but not permanent middle
cerebral artery occlusion. In the infarct region microglia are activated within
hours and within days transform into phagocytes. Astrocytes upregulate
intermediate filaments, synthesize neurotrophins and form glial scars. Local
microglia and infiltrating macrophages demarcate infarcts and rapidly remove
debris. Remote from the lesion no cellular infiltration occurs, but astroglia and
microglia are transiently activated. Astrocytic activation is induced by
spreading depression. In focal ischemia neurons die acutely by necrosis and in a
delayed fashion by programmed cell death, apoptosis. Proinflammatory cytokines
such as tumor necrosis factor-alpha and interleukin-1 beta are upregulated within
hours in ischemic brain lesions. Either directly or via induction of neurotoxic
mediators such as nitric oxide, cytokines may contribute to infarct progression
in the post-ischemic period. On the other hand, inflammation is tightly linked
with rapid removal of debris and repair processes. At present it is unclear
whether detrimental effects of inflammation outweigh neuroprotective mechanisms
or vice versa. In global ischemia inflammatory responses are limited, but micro-
and astroglia are also strongly activated. Glial responses significantly differ
between brain regions with selective neuronal death and neighbouring areas that
are more resistent to ischemic damage.
PMID- 9760700
TI - The origin and differentiation of microglial cells during development.
AB - Some authors claim that microglia originate from the neuroepithelium, although
most now believe that microglial cells are of mesodermal origin, and probably
belong to the monocyte/macrophage cell line. These cells must enter the
developing central nervous system (CNS) from the blood stream, the ventricular
space or the meninges. Afterward microglial cells are distributed more or less
homogeneously through the entire nervous parenchyma. Stereotyped patterns of
migration have been recognized during development, in which long-distance
tangential migration precedes radial migration of individual cells. Microglial
cells moving through the nervous parenchyma are ameboid microglia, which
apparently differentiate into ramified microglia after reaching their definitive
location. This is supported by the presence of cells showing intermediate
features between those of ameboid and ramified microglia. The factors that
control the invasion of the nervous parenchyma, migration within the developing
CNS and differentiation of microglial cells are not well known. These phenomena
apparently depend on environmental factors such as soluble or cell-surface bound
molecules and components of the extracellular matrix. Microglial cells within the
developing CNS are involved in clearing cell debris and withdrawing misdirected
or transitory axons, and presumably support cell survival and neurite growth.
PMID- 9760701
TI - The cerebellum in the spatial problem solving: a co-star or a guest star?
AB - The experimental findings reviewed here indicate that the cerebellum has to be
added to the regions known to be involved in the spatial learning. Cerebellar
function is specifically linked to 'how to find an object' rather than 'where the
object is in the space'. In the Morris water maze (MWM) hemicerebellectomized
(HCbed) rats displayed a severe impairment in coping with spatial information,
displaying only peripheral circling. And yet, when the MWM cue phase was
prolonged, HCbed rats succeeded in acquiring some abilities to learn platform
position, even in a pure place paradigm, such as finding a hidden platform with
the starting points sequentially changed. Conversely, whether the searching
strategy was acquired preoperatively, no exploration deficit appeared. Thus,
cerebellar lesions appear to affect the procedural components of spatial
function, sparing the declarative ones. When intact animals were non-spatially
pre-trained and then HCbed, they exhibited an expanded scanning strategy,
underlining the cerebellar involvement in procedural component acquisition. By
testing HCbed rats in an active avoidance task, first without and then with a
request for right/left discrimination, lesioned rats displayed severe deficits.
Thus, besides a marked impairment in facing procedural components of spatial
processing, cerebellar lesion provokes deficits also in right/left discrimination
task. In conclusion, it is possible to propose the cerebellum as one part of a
large system that includes frontal, posterior parietal, inferior temporal
cortices, hippocampus and basal ganglia. These structures form an allocentric
spatial system and an egocentric control system, that interlock to process the
information involved in representing an object in the space.
PMID- 9760702
TI - The effects of Aconitum alkaloids on the central nervous system.
AB - Preparations of Aconitum roots are employed in Chinese and Japanese medicine for
analgesic, antirheumatic and neurological indications. The recent surge in use of
phytomedicine derived from traditional Chinese medicine as well as increasing
concerns about possible toxic effects of these compounds have inspired a great
deal of research into the mechanisms by which certain Aconitum alkaloids may act
on the central nervous system. The pharmacological effects of preparations of
Aconitum roots are attributed to several diterpenoid alkaloids. The main alkaloid
of these plants is aconitine, a highly toxic diterpenoid alkaloid which is known
to suppress the inactivation of voltage-dependent Na+ channels by binding to
neurotoxin binding site 2 of the alpha-subunit of the channel protein. In this
article the pharmacology of several structurally related Aconitum alkaloids is
highlighted and their therapeutic vs toxic potential is discussed. Neurochemical
and neurophysiological studies will be reviewed with emphasis on the effects of
the alkaloids in regions of the brain that have been implicated in pain
transmission and generation of epileptic activity. Considering the chemical
structure of the Aconitum alkaloids as well as their mechanism of action, a
subdivision in three groups becomes obvious: the first group comprises such
alkaloids which possess high toxicity due to two ester boundings at the diterpene
skeleton. The members of this group activate voltage-dependent sodium channels
already at resting potential and inhibit noradrenaline reuptake. Activation of
sodium channels and in consequence excessive depolarization with final
inexcitability and suppression of pain transmission account for their
antinociceptive properties. The second group comprises less toxic monoesters
which have been shown to possess strong antinociceptive, antiarrhythmic and
antiepileptiform properties due to a blockade of the voltage-dependent sodium
channel. Electrophysiological studies have revealed a use-dependent inhibition of
neuronal activity by these alkaloids. They seem to be competitive antagonists of
the group I-alkaloids. The third group of Aconitum alkaloids are lacking an ester
side chain in the molecule. Toxicity is markedly reduced when compared with the
two other groups. They fail to affect neuronal activity, but are reported to have
antiarrhythmic actions suggesting that they may have different affinities to
various subtypes of the alpha-subunit of the Na+ channel in brain and heart.
PMID- 9760703
TI - Release of neurotransmitters in the locus coeruleus.
AB - In the past 15 years the release of neurotransmitters and their metabolites in
the locus coeruleus (LC) has been studied by using three approaches:
microdialysis; push-pull superfusion; and voltammetry. These sophisticated
techniques, which render it possible to follow the time course and magnitude of
neurochemical changes in anaesthetized and conscious animals, have permitted
great strides towards understanding neurotransmission in the LC. It appears that
noradrenaline, known to be released in distant terminal fields, is also released
in the somatodendritic area of LC neurons in response to drugs and physiological
stimuli. Furthermore, determination of in vivo release enables the identification
of functionally important neurotransmitter systems involved in relaying and
integrating information reaching the LC via afferent neurons. As outlined in this
review, the release rates of glutamate, aspartate, gamma-aminobutyric acid,
glycine, 5-hydroxytryptamine and catecholamines, are modified in particular by
arousing and stressful stimuli, pain, changes in cardiovascular homeostasis, as
well as during opioid withdrawal or the sleep-wake-cycle. Profound interactions
also occur between some of the neurotransmitters released during these
situations. It appears that individual stimuli produce distinct neurochemical
changes which contribute to the regulation of neuronal LC activity. Stimuli that
activate LC neurons, such as pain, fall of blood pressure, noise, opiate
withdrawal, do not produce a uniform response but modality-specific release
patterns of excitatory and inhibitory neurotransmitters within the LC. From these
studies and from existing neuroanatomical and electrophysiological data our
knowledge of how neurotransmitters work in concert to regulate the functional
state of LC noradrenergic perikarya in physiological and pathophysiological
conditions is just emerging.
PMID- 9760704
TI - Potent suppressive activity of chlorophyll a and b from green tea (Camellia
sinensis) against tumor promotion in mouse skin.
AB - Potent antigenotoxic and anti-tumor promoting activities of chlorophyll a from
green tea (camellia sinensis) have been shown using in vitro cell culture
experiments (Okai Y. et al. (1996) Mutation Res., 370, 11-17). In the present
study, the authors analyzed in vivo effects of chlorophyll a and b from green tea
on tumor promotion in mouse skin in the following ways. 1. When chlorophyll a and
b from green tea were applied before each treatment by a tumor promoter, 12-O
tetradecanoyl-phorbol-13-acetate (TPA) on BALB/c mouse skin initiated by 7, 12
dimethylbenz [a] an-thracene (DMBA), they caused significant suppression in a
dose-dependent manner against BALB/c mouse skin tumorigenesis. 2. Chlorophyll a
and b showed significant suppressive effects against TPA-induced inflammatory
reaction such as edema formation in BALB/c mouse ear skin in a dose-dependent
fashion. These results suggest that chlorophyll a and b possess potent
suppressive activities against tumor promotion in mouse skin.
PMID- 9760705
TI - [AHP analysis of activities expected of public health nurses at a public health
center].
AB - The activities expected of Public Health Nurses (PHN) at a Public Health Center
(PHC) were evaluated by the AHP technique based on the results of a Focus Group
Discussion among 7 PHNs working in K PHC, Fukuoka. Among the five PHN activities,
"Collection and analysis of information" was evaluated as the most important,
followed by "Consultation", "Coordination of different sectors", "Control and
support of patients with chronic diseases", and "Health education for the
public". However, the investigated PHNs concluded that their knowledge of and
skill in doing "Collection and analysis of information" are insufficient. It is
therefore recommended that continuous training courses on statistics and
epidemiology be organized for the PHNs.
PMID- 9760706
TI - [A plan of the life-long learning support system of UOEH--possibility for the
introduction of distance learning system by the Internet].
AB - In order to keep up with the rapid advance in knowledge and skills in various
industrial sectors, the needs for the life-long learning has increased recently.
This is also the case for the University of Occupational and Environmental
Health, Japan, which has as its aim the education of occupational health
specialists. In fact, there are many universities and colleges which have
organized some post-graduate courses for the workers. However, most of these
courses are for workers who can come to classes in the daytime or evening. In the
case of UOEH, it is not enough to organize such type of classes in order to
respond to the social needs, because it has to offer an opportunity of life-long
learning for all occupational health specialists in all parts of Japan. In order
to solve this problem, it is recommended that a distance learning system based on
modern information technology such as the internet be organized. In this report,
the authors present the distance learning system of Wisconsin University in the
USA, and that of Tamagawa Gakuen University of Japan. After evaluating these two
systems, a plan for a life-long learning support system of UOEH is suggested,
which consists of a distance learning system based on the internet.
PMID- 9760707
TI - [Trends of the biological monitoring measurements from 1991 to 1995].
AB - Partial amendments to the Japanese Regulation on the Prevention of Lead Poisoning
and that of Organic Solvent Poisoning were made in 1989. As a result, the
measurement of blood lead and urinary delta-aminolevulinic acid (delta-ALA)
became indispensable items of the occupational health examination for workers who
handle lead. Also, the measurement of urinary metabolites of workers who handle
eight kinds of organic solvents (xylene, N,N-dimethylformamide, styrene,
tetrachloroethylene, 1,1,1-trichloroethane, trichloroethylene, toluene, and
normal-hexane) became mandatory. The results of the biological monitoring
mentioned above are classified into one of three categories, that is,
distribution 1, 2 and 3, according to the concentration of the determinants. In
this paper, the incidence of distribution 1, 2 and 3 of each determinant is
reported and its change from 1991 to 1995 is discussed. The incidence of
distribution 3 was 0.1-5.0% in each determinant. Although the ratio of
distribution 1, 2 and 3 seems to have been almost the same for 5 years some
determinants decreased their percentage of distribution 3. It is important to
utilize the biological monitoring results for the improvement of working
environments and working styles, and health management.
PMID- 9760708
TI - [Expertise in occupational health nursing (II)--Report on the 17th UOEH
International Symposium].
AB - Three hundred and fifty-two OHNs and collaborative persons from 17 countries and
the ILO assembled at UOEH to participate in the 17th UOEH International Symposium
to commemorate the inauguration of the UOEH School of Health Sciences from
October 20 to 22, 1997. The main theme of this Symposium was "Occupational Health
Nurse (OHM) Expertise." The Symposium was opened by greetings from Dr. Akira
Koizumi, followed by a message from ILO presented by Dr. G.H. Cappee, head of the
Medical Section Occupational Safety & Health Branch, ILO. Dr. Bonnie Rogers of
North Carolina University, Chapel Hill, and President of AAOHN, lectured on the
main theme of the Symposium, and Dr. M.A. Fingerhut gave a lecture on
"Partnership in Occupational Safety and Health." At the general sessions, 5
themes were discussed.--1) Partnership in Occupational Health, 2) Education and
Training of OHNs, 3) Intervention/Behavior to Disease Prevention and Health
Promotion, 4) How to Integrate Computing into Occupation Health Nursing and 5)
Cost/Benefit Effectiveness of Occupational Health Nursing. For all 5 sessions,
there were keynote lectures, oral and poster presentations. This report reviews
the lectures by Dr. B. Rogers on "Expertise in Occupational Health Nursing," by
Dr. Kuchinski on "Education and Training of Occupational Health Nurses in The
US," the presentation by Mrs. J. Fanchette, DIUST/GIT Service de Pathologie
Professionnelle Hospital Civil, France, on "Evaluation of An Interuniversity
Diploma Course Occupational Health Nurse Qualification," by Dr. K. June,
Soonchunhyang Univ., Korea, on "Transition of Occupational Health Nursing
Education in Korea" and finally, the lecture by Dr. F. Mitsuhashi on "Revisions
in the Industrial Safety and Health Law and Expected Models for Occupational
Health Nursing Staff."
PMID- 9760709
TI - [Is subjective health status a good predictor of work resumption?].
AB - The aim of the study is to investigate how persons with long term work-disability
due to low back pain assess their health status and how the subjective health
measurement influence work resumption (n = 663). Information on their subjective
health status at 42 days after start of work-disability is set in relation to the
outcomes "Continued work disability after 84 days" versus "work resumption". Bi-
and multivariate analysis show that information on the subjective health status
and the subjective work prognosis differs between both groups already after 42
days. The results show that the subjective health status in connection with the
subjective work prognosis is a good predictor for "Non-resumption of work", but
not a sufficiently good predictor for "Resumption to work".
PMID- 9760710
TI - [Economic evaluation in a trial of medically controlled prescription of narcotics
to dependent users (PROVE)].
AB - In the 1994-1996 trial of medically controlled prescription of narcotics to
dependent users, 800 places were ascribed to heroin substitutes and another 200
for methadone and morphine substitutes. The trial was evaluated with the aid of
an accompanying research. Among the results demonstrated in the evaluation was an
improvement of the health of the participants. The economic assessment was drawn
from observations of health effects within a sub-sample of 142 participants from
four centers. In a retrospective statistical survey, for each acute illness which
could be influenced through the trial, the number of diagnoses was recorded in
the first and thirteenth month after study entry. Also, based on a number of
representative cases for each of these acute illnesses, the resource use, i.e.
the types and numbers of medical products and services rendered to the patients,
was recorded. The results showed a clear decline in depressive episodes, skin
diseases, digestive system disorders as well as epileptic attacks and
intoxication. Treatment costs could be reduced from a total of CHF 94875.--to CHF
21,998.--/month or from CHF 22.27 to CHF 5.15/patient per day. The improvement of
somatic and psychic health due to the medically controlled prescription of
narcotics resulted in a benefit of CHF 17.11/person per day.
PMID- 9760711
TI - [Fractures in the elderly: are postal questionnaires sufficiently sensitive?].
AB - Within the European Prospective Osteoporosis Study the validity of a postal
questionnaire concerning fractures in the elderly was assessed. A sample of 144
men and women aged 50 to 84 hospitalized in an urban hospital due to fractures
within the past 12 months was investigated. Eight percent of the respondents
denied any recent fracture and turned out to be false negatives, less than
previously recorded. Mode and frequency of questioning seem to influence the
results. To assess fracture localisation, we used a graphical method (mannequin).
Due to various factors, one third of all localisations were incorrect.
PMID- 9760712
TI - Parturient haemoglobinuria in buffaloes--a review.
AB - Parturient haemoglobinuria is a disease of economic importance in buffalo rearing
countries in general and in India, Pakistan and Egypt in particular. This study
reviews the information on aetiology, epidemiology, clinical aspects and
treatment of parturient haemoglobinuria in buffaloes. The body of literature
reviewed suggests that phosphorus deficiency in the diet of affected animals
plays a major role in causing this disease, although the precise mechanism
involved is complex. The possible factors involved and their interplay, plus the
clinical picture of affected animals and the results of different preventive and
therapeutic regimes are discussed. The study also identifies areas for further
research.
PMID- 9760713
TI - Control of foot-and-mouth disease through vaccination and the isolation of
infected animals.
AB - Foot-and-mouth disease (FMD) within Saudi Arabian dairy herds has been controlled
for the past decade through vaccination. Data from 19 outbreaks on Saudi farms
has suggested that the durability of these vaccines extended for 2.5 months,
providing an 81-98% level of protection. Vaccination has nevertheless failed to
prevent the establishment and sometimes persistence of the disease. This is
probably because the highly contagious nature of FMD creates increasing levels of
viral excretion during an outbreak, and the co-habitation in Saudi farms of
affected/susceptible animals following diagnosis, predisposes the herds to re
infection. Pre-clinical excretion of the virus leads to the infection of
additional in-contact susceptible animals prior to diagnosis, so the isolation of
clinically infected animals does not guarantee a removal of infection. Saudi
Arabian farms are subdivided into managed farm pens and isolation (away from the
farm) of all animals in infected pens not only removes the infectious individuals
showing clinical signs, but also those that are sub-clinical and excreting virus.
Simulations suggest that removing all infectious animals from the herd
significantly reduces the per cent infected in the herd.
PMID- 9760714
TI - Evaluation of hyperimmune sera against goat pox viral antigens.
AB - Laboratory diagnosis of goat poxvirus (GPV) requires suitable diagnostic reagents
(sera and antigens). GPV-infected scab suspension has been used as antigen for
production of hyperimmune sera (HIS) by several workers (Pandey and Singh, 1972;
Tantawi et al., 1980; Sharma et al., 1988). This antiserum sometimes reacts non
specifically in routine laboratory tests such as the agar gel precipitation test
(AGPT) and counter-immunoelectrophoresis (CIE) (Sharma et al., 1988). Production
of specific goat pox antiserum involves its adsorption with healthy goat-skin
triturate. The present work evaluated various HIS raised against different
antigens of GPV in order to develop an antiserum for laboratory diagnosis of goat
pox infections without any non-specificity.
PMID- 9760715
TI - Isolation of Mycobacterium species from raw milk of pastoral cattle of the
Southern Highlands of Tanzania.
AB - A study to determine the secretion of Mycobacterium spp. in milk from indigenous
cattle was carried out in pastoral cattle reared in the Southern Highlands to
Tanzania. The study was aimed at elucidating the dangers associated with milk
borne zoonoses in a society where milk is normally consumed raw. Out of 805 milk
samples, 31 (3.9%) were positive for mycobacteria. There was a preponderance of
atypical mycobacteria (87%) whereas only two isolates (6.5%) were confirmed as M.
bovis. Atypical mycobacteria included: M. terrae (n = 7), M. fortuitum (n = 2),
M. flavescens (n = 13), M. gordonae (n = 1) and M. smegmatis (n = 4). Although
the number of M. bovis positive samples was low, the habit of pooling milk may
still pose great public health dangers to milk consumers in this part of the
world. Moreover, isolation of atypical mycobacteria should also be considered to
be a danger to human health in countries such as Tanzania, where the number of
people with lowered immunity due to HIV infection is on the increase.
PMID- 9760716
TI - Getah virus infection of Indian horses.
AB - An outbreak of disease, characterized by depression, anorexia, fever, limb oedema
and lymphocytopenia, occurred on a farm for thoroughbreds in India in 1990.
Twenty-six of the 88 horses on the farm were affected, predominantly adults.
Signs were present in affected horses for 7-10 days, and the outbreak lasted 21
days. Seven of the 26 affected horses were tested for exposure to Getah virus
using paired serum samples, acute and convalescent. Four of the 7 horses
seroconverted to Getah virus, and the other three showed a 4-fold or greater rise
in titre. The clinical and laboratory findings were similar, but not indentical,
to those described in natural and experimental infections in Japanese horses.
This is the first description of disease caused by Getah virus infection in
horses outside Japan. In addition serum samples from 152 horses from 3 regions of
India were evaluated for the presence of antibodies to Getah virus. The
seroprevalence was found to be 17%, indicating exposure to the virus elsewhere in
Indian horses.
PMID- 9760717
TI - Comparative evaluation of IHA and CIEP in the diagnosis of Toxocara vitulorum in
pregnant cows and buffaloes.
PMID- 9760718
TI - Prospects and strategies for genetic improvement of the dairy potential of
tropical cattle by selection.
AB - The import of genetic material and the use of crossbreeding to improve the dairy
merit of tropical cattle has been criticized for eroding the livestock genetic
resources of the tropics. An alternative is genetic improvement of the indigenous
cattle through selection. The objective of the present paper is to examine the
feasibility of this alternative. Constraints to genetic improvement of tropical
cattle through selection are discussed. Low reproductive rates and high calf
mortality reduce the intensity of selection. The generation interval, which is
long in cattle, is further prolonged by the late sexual maturity and the long
calving intervals in most tropical breeds. The most serious constraint is,
however, that the extensive milk recording schemes which support dairy cattle
breeding programmes in many temperate countries are almost non-existent in the
tropics. In this situation, the most realistic approach to improvement through
selection is to start with a single nucleus herd (or a group of cooperating
herds). Two alternative selection programmes (with and without progeny testing)
for a closed herd of 500 cows are outlined. The alternative which assumed no
progeny testing, i.e. selection of bulls on pedigree information only, gave the
fastest genetic improvement (predicted at 36 kg/year). By distributing breeding
bulls from the herd the genetic progress can be disseminated to the outside
population with a time lag of about two generations. A nucleus herd can supply
about 15 selected bulls per 100 cows in the herd per year, enough for a
population of several thousand cows.
PMID- 9760719
TI - 3,4-Bis(1-adamantyl)-1,2-dithiete: the first structurally characterized dithiete
unsupported by a ring or benzenoid frame.
AB - The structure determination of 3,4-bis(1-adamantyl)-1,2-dithiete, (C10H15)2C2S2
or C22H30S2, reported herein is the first crystallographic characterization of a
1,2-dithiete molecule unsupported by a benzenoid frame. Two independent molecules
exist in the asymmetric unit separated by a pseudo-inversion center. The S2C2
four-membered dithiete ring is planar, with a trapezoidal shape enforced by the
longer disulfide bond [average 2.086 (2) A] compared with the olefinic bond
[average 1.363 (6) A]. The adamantyl substituents differ from one another by
adopting slightly different rotational conformations with respect to the dithiete
ring. The quaternary C atoms of the adamantyl groups deviate only slightly from
the plane of the dithiete ring (average displacement of 0.023 A).
PMID- 9760720
TI - Ortho-(1-naphthoyl)benzoic acid.
AB - The title acid, C18H12O3, crystallized in the centrosymmetric space group C2/c
and exhibits carboxyl group hydrogen bonding of the cyclic dimer type about a
center of symmetry. The Odonor-Oacceptor distance in the hydrogen bond is 2.692
(2) A. In addition, seven C-H groups and the three O atoms in the molecule are
involved in significantly attractive C-H...O interactions with 11 neighbors,
forming a three-dimensional network. The carboxylic H atom is ordered, as are the
carboxylic O atoms.
PMID- 9760721
TI - The RNA folding problem: a variational problem within an adiabatic approximation.
AB - Biopolymer folding is an expeditious process taking place within timescales
incommensurably shorter than ergodic times. Furthermore, its robustness suggests
that the process must depend on a relatively coarse level of resolution of
conformation space. To account for these features while focusing on the RNA
context, we derive a variational principle formulated within an adiabatic
approximation obtained by integrating out fast-relaxing molecular motions.
Folding pathways are generated by means of a stochastic process which begets a
least effort principle reflecting a stepwise minimization of the conformational
entropy cost for each folding event with concurrent maximization of the base
pairing. This economy of the process is found to have kinetic consequences if we
treat base-pairing contact patterns (BPPs) adiabatically, that is, as quasi
equilibrium states: the probability distribution of overall folding timespans
associated to the process resolved at the BPP level is maximized at the
brachistochrone or overall least-time pathway for functionally-competent RNAs. In
turn, this pathway is shown to yield all the phylogenetically-conserved
structural features of the active conformation within biologically-relevant
timescales.
PMID- 9760722
TI - Calculation of concentrations of equilibrium components in an in vitro activity
test of vancomycin antibiotics and the possible mode of action.
AB - The vancomycin group of antibiotics is considered to act by binding the bacterial
cell wall mucopeptide precursor terminating in -L-Lys-D-Ala-D-Ala. The
dimerization of these antibiotics is also believed to play a role in the action.
In this paper, we analyzed the equilibria in the in vitro antibacterial activity
test of the vancomycin antibiotics both with and without the cell wall precursor
analogue di-acetyl-L-Lys-D-Ala-D-Ala (DALAA). Based on the equilibria and
concentration balance, we obtained 10 equations (seven quadratic equations and
three linear equations) containing 10 equilibrium concentrations which relate to
the antibiotic, cell wall precursor and DALAA. A computer program was written to
solve these equations from known dimerization constant and the binding constants
(both monomer and dimer) with DALAA of the antibiotic. The concentrations in the
test for vancomycin and eremomycin were obtained. The antibiotic activity of
these antibiotics may be quantitatively correlated with their dimerization
constants and the binding constants through the calculation. By analyzing the
calculated results, we concluded that the cell wall-bound dimer may be the major
contributor to the antibiotic activity in the case of eremomycin, while the cell
wall-bound monomer is possibly the determinant for the activity of vancomycin.
PMID- 9760723
TI - Excess counterion binding and ionic stability of kinked and branched DNA.
AB - We compute the excess number of counterions associated with kinked and branched
DNA, and the ionic stabilities of these structures as a function of chain length
and both sodium and magnesium salt concentration, using numerical counterion
condensation theory. The DNA structures are modeled as two or more finite lines
of phosphate charges radiating from the kink or junction center. The number of
excess counterions around the (40-90 degrees) kinked duplex is very small (at
most four). The geometries of large three- and four-way DNA junctions (with > 50
base pairs per arm) in solutions containing low to moderate NaCl concentrations,
by contrast, accumulate a substantial number of excess sodium ions (> 20) but no
more than 15 magnesium counterions. The excess number of counterions surrounding
the kinked linear chain and the branched DNA structures either remains invariant
or increases with chain length, tending to reach a plateau value. Open
configurations, such as the planar Y-shaped three-way junction (with three 120
degrees inter-arm angles) and the 90 degrees cross-shaped four-way junction, are
ionically more stable than compact geometries, such as pyramidal three-way
junctions and X-shaped four-way junctions, over the entire range of salt
concentration considered (10(-5)-10(-1) M NaCl or MgCl2). The ionic stabilities
of the compact forms increase with increasing salt concentration and become
comparable to those of the extended geometries at high salt (especially when
magnesium is the supporting salt).
PMID- 9760724
TI - New insights into microtubule structure and function from the atomic model of
tubulin.
AB - The structure of tubulin has recently been solved by electron crystallography of
zinc-induced tubulin sheets. Because tubulin was studied in a polymerized state,
the model contains information on the interactions between monomers that give
rise to the alpha beta dimer as well as contacts between adjacent dimers that
result in the structure of the protofilament. The model includes the binding site
of taxol, an anti-cancer agent that acts by stabilizing microtubules. The present
tubulin model gives the first structural framework for understanding microtubule
polymerization and its regulation by nucleotides and anti-mitotic drugs at the
molecular level.
PMID- 9760725
TI - General features of the recognition by tubulin of colchicine and related
compounds.
AB - The kinetic mechanisms of the binding to tubulin of colchicine and eight
different analogues have been studied to elucidate details of the recognition
mechanism. All of the analogues follow a two step binding mechanism i.e. binding
occurs via an initial step with low affinity, followed by an isomerisation of the
initial complex leading to the final high affinity state. For several analogues
the kinetic and thermodynamic data of both processes are compared here. For all
the analogues the delta G1 degree of initial binding at 25 degrees C varies
between -13.3 and -28.8 kJ. mol-1. For the second step delta G2 degrees varies
between -2.4 and -27 kJ. mol-1. These limited ranges of free energy change are,
however, obtained by a great variety of enthalpy changes and compensatory entropy
changes. Comparison of the data for the first and second steps indicates that
structural alterations of the drugs always change the thermodynamic parameters of
the two steps, and the changes in the first and the second steps are in opposite
directions. The fact that this range of experimental behaviour can be
incorporated into a general mechanism encourages the extension of these
investigations to other colchicine analogues and related compounds with potential
pharmaceutical applications.
PMID- 9760726
TI - Organisation and structure of microtubules and microtubule-motor protein
complexes.
AB - We present a short overview of the current status of work on the organisation and
structure of microtubules and of microtubule-motor protein complexes. At present
there is great interest in obtaining structural information that can help us to
understand the movement of the kinesin family of microtubule associated molecular
motors. Using electron cryomicroscopy and image reconstruction methods three
dimensional maps of microtubule-motor complexes have been obtained in the
presence of different nucleotides. We address a number of principles involved in
different aspects of this work.
PMID- 9760727
TI - Conformations of kinesin: solution vs. crystal structures and interactions with
microtubules.
AB - Recently, the molecular structures of monomeric and dimeric kinesin constructs in
complex with ADP have been determined by X-ray crystallography (Kull et al. 1996;
Kozielski et al. 1997 a; Sack et al. 1997). The "motor" or "head" domains have
almost identical conformations in the known crystal structures, yet the kinesin
dimer is asymmetric: the orientation of the two heads relative to the coiled-coil
formed by their neck regions is different. We used small angle solution
scattering of kinesin constructs and microtubules decorated with kinesin in order
to find out whether these crystal structures are of relevance for kinesin's
structure under natural conditions and for its interaction with microtubules. Our
preliminary results indicate that the crystal structures of monomeric and dimeric
kinesin are similar to their structures in solution, though in solution the
center-of-mass distance between the motor domains of the dimer could be slightly
greater. The crystal structure of dimeric kinesin can be interpreted as
representing two equivalent conformations. Transitions between these or very
similar conformational states may occur in solution. Binding of kinesin to
microtubules has conformational effects on both, the kinesin and the microtubule.
Solution scattering of kinesin decorated microtubules reveals a peak in intensity
that is characteristic for the B-surface lattice and that can be used to monitor
the axial repeat of the microtubules under various conditions. In decoration
experiments, dimeric kinesin dissociates, at least partly, leading to a
stoichiometry of 1:1 (one kinesin head per tubulin dimer; Thormahlen et al.
1998a) in contrast to the stoichiometry of 2:1 reported for dimeric ncd. This
discrepancy is possibly due to the effect of steric hindrance between kinesin
dimers on adjacent binding sites.
PMID- 9760728
TI - The role of the dynein stalk in cytoplasmic and flagellar motility.
AB - We have recently identified a microtubule binding domain within the motor protein
cytoplasmic dynein. This domain is situated at the end of a slender 10-12 nm
projection which corresponds to the stalks previously observed extending from the
heads of both axonemal and cytoplasmic dyneins. The stalks also correspond to the
B-links observed to connect outer arm axonemal dyneins to the B-microtubules in
flagella and constitute the microtubule attachment sites during dynein motility.
The stalks contrast strikingly with the polymer attachment domains of the
kinesins and myosins which are found on the surface of the motor head. The
difference in dynein's structural design raises intriguing questions as to how
the stalk functions in force production along microtubules. In this article, we
attempt to integrate the myriad of biochemical and EM structural data that has
been previously collected regarding dynein with recent molecular findings, in an
effort to begin to understand the mechanism of dynein motility.
PMID- 9760729
TI - Fluctuation driven transport and models of molecular motors and pumps.
AB - Non-equilibrium fluctuations can drive vectorial transport along an anisotropic
structure in an isothermal medium by biasing the effect of thermal noise (kBT).
Mechanisms based on this principle are often called Brownian ratchets and have
been invoked as a possible explanation for the operation of biomolecular motors
and pumps. We discuss the thermodynamics and kinetics for the operation of
microscopic ratchet motors under conditions relevant to biology, showing how
energy provided by external fluctuations or a non-equilibrium chemical reaction
can cause unidirectional motion or uphill pumping of a substance. Our analysis
suggests that molecular pumps such as Na,K-ATPase and molecular motors such as
kinesin and myosin may share a common underlying mechanism.
PMID- 9760730
TI - Limited flexibility of the inter-protofilament bonds in microtubules assembled
from pure tubulin.
AB - The superposition of the regular arrangement of tubulin subunits in microtubules
gives rise to moire patterns in cryo-electron micrographs. The moire period can
be predicted from the dimensions of the tubulin subunits and their arrangement in
the surface lattice. Although the average experimental moire period is usually in
good agreement with the theoretical one, there is variation both within and
between microtubules. In this study, we addressed the origin of this variability.
We examined different possibilities, including artefacts induced by the
preparation of the vitrified samples, and variations of the parameters that
describe the microtubule surface lattice. We show that neither flattening nor
bending of the microtubules, nor changes in the subunit dimensions, can account
for the moire period variations observed in 12 and 14 protofilament microtubules.
These can be interpreted as slight variations, in the range -0.5 A to +0.9 A, of
the lateral interactions between tubulin subunits in adjacent protofilaments.
These results indicate that the inter-protofilament bonds are precisely
maintained in microtubules assembled in vitro from pure tubulin. The fact that
the moire period is not affected by bending indicates that the local interactions
between tubulin subunits are sufficiently stiff to accommodate large deformations
of the microtubule wall.
PMID- 9760731
TI - Modeling elastic properties of microtubule tips and walls.
AB - Electron micrographs of tips of growing and shrinking microtubules are analyzed
and interpreted. The many shapes observed are all consistent with a simple
mechanical model, a flexible tube with competing intrinsic curvatures.
Observations are also consistent with growing and shrinking microtubules having
the same intrinsic curvature for protofilaments, the one observed in oligomers
peeling off shrinking microtubules. If this is so, the lateral bonds between
protofilaments are responsible for the difference between shapes of tips on
growing and shrinking microtubules.
PMID- 9760732
TI - Diffusion inside microtubules.
AB - Recent high-resolution analysis of tubulin's structure has led to the prediction
that the taxol binding site and a tubulin acetylation site are on the interior of
microtubules, suggesting that diffusion inside microtubules is potentially a
biologically and clinically important process. To assess the rates of transport
inside microtubules, predictions of diffusion time scales and concentration
profiles were made using a model for diffusion with parameters estimated from
experiments reported in the literature. Three specific cases were considered: 1)
diffusion of alpha beta-tubulin dimer, 2) diffusion/binding of taxol, and 3)
diffusion/binding of an antibody specific for an epitope on the microtubule's
interior surface. In the first case tubulin is predicted to require only
approximately 1 min to reach half the equilibrium concentration in the center of
a 40 microns microtubule open at both ends. This relatively rapid transport
occurs because of a lack of appreciable affinity between tubulin and the
microtubule inner surface and occurs in spite of a three-fold reduction in
diffusivity due to hindrance. By contrast the transport of taxol is much slower,
requiring days (at nM concentrations) to reach half the equilibrium concentration
in the center of a 40 microns microtubule having both ends open. This slow
transport is the result of fast, reversible taxol binding to the microtubule's
interior surface and the large capacity for taxol (approximately 12 mM based on
interior volume of the microtubule). An antibody directed toward an epitope in
the microtubule's interior is predicted to require years to approach equilibrium.
These results are difficult to reconcile with previous experimental results where
substantial taxol and antibody binding is achieved in minutes, suggesting that
these binding sites are on the microtubule exterior. The slow transport rates
also suggest that microtubules might be able to serve as vehicles for controlled
release of drugs.
PMID- 9760733
TI - A mathematical approach to cytoskeletal assembly.
AB - The cytoskeleton is a fundamental and important part of cell's structure, and is
known to play a large role in controlling the shape, function, division, and
motility of the cell. In recent years, the traditional biological and biophysical
experimental work on the cytoskeleton has been enhanced by a variety of
theoretical, physical and mathematical approaches. Many of these approaches have
been developed in the traditional frameworks of physicochemical and statistical
mechanics or equilibrium thermodynamic principles. An alternative is to use
kinetic modelling and couch the analysis in terms of differential equations which
describe mean field properties of cytoskeletal networks or assemblies. This paper
describes two such recent efforts. In the first part of the paper, a summary of
work on the kinetics of polymerization, fragmentation, and dynamics of actin and
polymers in the presence of gelsolin (which nulceates, fragments, and caps the
filaments) is given. In the second part, some of the kinetic models aimed at
elucidating the spatio-angular density distribution of actin filaments
interacting via crosslinks is described. This model given insight into effects
that govern the formation of clusters and bundles of actin filaments, and their
spatial distribution.
PMID- 9760734
TI - A computational model of ameboid deformation and locomotion.
AB - Traditional continuum models of ameboid deformation and locomotion are limited by
the computational difficulties intrinsic in free boundary conditions. A new model
using the immersed boundary method overcomes these difficulties by representing
the cell as a force field immersed in fluid domain. The forces can be derived
from a direct mechanical interpretation of such cell components as the cell
membrane, the actin cortex, and the transmembrane adhesions between the
cytoskeleton and the substratum. The numerical cytoskeleton, modeled as a dynamic
network of immersed springs, is able to qualitatively model the passive
mechanical behavior of a shear-thinning viscoelastic fluid (Bottino 1997). The
same network is used to generate active protrusive and contractile forces. When
coordinated with the attachment-detachment cycle of the cell's adhesions to the
substratum, these forces produce directed locomotion of the model ameba. With
this model it is possible to study the effects of altering the numerical
parameters upon the motility of the model cell in a manner suggestive of genetic
deletion experiments. In the context of this ameboid cell model and its numerical
implementation, simulations involving multicellular interaction, detailed
internal signaling, and complex substrate geometries are tractable.
PMID- 9760735
TI - Reliability of file-based retrospective ratings of psychopathy with the PCL-R.
AB - A rapidly emerging consensus recognizes Hare's Psychopathy Checklist-Revised (PCL
R; Hare, 1991) as the most valid and useful instrument to assess psychopathy
(Fulero, 1995; Stone, 1995). We compared independent clinical PCL-R ratings of 40
forensic adult male criminal offenders to retrospective file-only ratings. File
based PCL-R ratings, in comparison to the clinical ratings, yielded categorical
psychopathy diagnoses with a sensitivity of .57 and a specificity of .96. The
intraclass correlation (ICC) of the total scores as estimated by ICC(2,1) was
.88, and was markedly better on Factor 2, ICC(2,1) = .89, than on Factor 1,
ICC(2,1) = .69. The findings support the belief that for research purposes, file
only PCL-R ratings based on Swedish forensic psychiatric investigation records
can be made with good alternate-form reliability.
PMID- 9760736
TI - Assessment of adherence with multiple informants in pre-adolescents with spina
bifida: initial development of a multidimensional, multitask parent-report
questionnaire.
AB - Adherence to medical regimens was assessed in 67 pre-adolescents with spina
bifida (8- and 9-year-olds; 37 boys, 30 girls), with mother, father, teacher, and
health professional report. The Parent-Report of Medical Adherence in Spina
Bifida Scale (PROMASB) was developed and includes multidimensional scales for the
following tasks: catheterization, bowel care, skin care, medication, and
ambulation. With few exceptions, the PROMASB has adequate psychometric
properties. However, findings revealed modest to low correlations between
respondents. Mothers and fathers reported significantly more noncompliance than
teachers and health professionals. For the most part, all informants reported
that most children were compliant across all tasks. Additional analyses based on
qualitative data suggest that parents attribute compliance difficulties to
motivational as well as attentional-memory factors.
PMID- 9760737
TI - The impact of "managed care" on the practice of psychological testing:
preliminary findings.
AB - Although the impact of managed care constraints on assessment practices has
received recent attention, a review of the literature found no data-based
articles that address this issue. We report survey data on 137 members of the
National Register of Health Service Providers in Psychology (Council for the
National Register of Health Service Providers in Psychology, 1996) on current
testing practices. The majority (72%) reported that their use of tests has
changed in the last 5 years due to managed care directives. These clinicians are
doing less testing overall and restrict their pool of assessment instruments. The
Rorschach inkblot technique (Rorschach, 1942), the Thematic Apperception Test
(Murray, 1943), and the Wechsler Intelligence scales (Matarazzo, 1972) were the
instruments most noted for disuse. Apparently, practitioners are relying more on
short, brief self-report measures that tap targeted symptoms or problem areas,
and less on tests that demand considerable clinicians' time. Implications and
limitations of the findings are discussed.
PMID- 9760738
TI - Identifying psychological contributions to chronic pain complaints with the MMPI
2: the role of the K scale.
AB - Although the 1-3/3-1 Minnesota Multiphasic Personality Inventory (MMPI) code type
is traditionally interpreted as suggesting that somatic complaints are caused or
exacerbated by psychological factors, prior research has raised questions about
the validity of this interpretation for chronic pain patients. This study
examined alternative strategies for using the MMPI to identify psychological
contributions to chronic pain complaints. A sample of 125 chronic pain patients
completed the MMPI-2. They were also rated by clinical staff on a set of
descriptive statements reflecting psychological features that can contribute to
physical complaints. MMPI patterns that are traditionally used to identify these
features, such as the 1-3/3-1 code type, were not related to the ratings. A
relation was found between scores on the K scale and the ratings, where patients
with higher scores on the K scale (T > or = 56) received ratings suggesting less
of a psychological contribution to their pain complaints. The implications of the
findings for understanding the nature of the K scale are discussed.
PMID- 9760739
TI - Further validation for the Cramer Defense Mechanism Manual.
AB - This article presents psychometric properties of the Cramer Defense Mechanism
Manual (Cramer, 1991b) for the Thematic Apperception Test (Murray, 1943). The
developmental hierarchy of defenses originally postulated by Cramer was supported
in this cross-sectional sample. Gender differences and the validity of
distinguishing between "mature" and "immature" levels of defense were also
investigated. Findings for gender differences largely replicate those previously
reported by Cramer (1987, 1991a). Results also support the view of a
developmental hierarchy of defenses and the validity of distinguishing between
mature and immature levels of two of the three types of defenses.
PMID- 9760740
TI - Childhood celebrity, parental attachment, and adult adjustment: the young
performers study.
AB - The associations between celebrity, parental attachment, and adult adjustment
were examined among 74 famous, former young performers in television and film. As
adults, former young performers whose parents served as their professional
managers viewed their mothers as less caring and more overcontrolling than did
performers whose parents were not their managers. Other factors affecting the
quality of the parent-child relationship included dissatisfaction with money
management, poor peer support, the perception that involvement in acting was
determined by others, and the specific nature of professional experience.
Together, these variables accounted for 59% of the variance in perceived caring
and 40% of the variance in perceived autonomy support. The relation could not be
attributed to a generalized response bias, as attachment was unrelated to degree
of positive thinking. A Celebrity x Parental Attachment interaction indicated
that the quality of the parent-child relationship moderated the effects of
celebrity on adult adjustment: Among participants with good parental attachment,
there was no relation between professional experience and adjustment; however,
among participants with poor attachment, this relation was strong. Possible
implications for parenting child actors and analogous populations of talented
children in high-stress arenas are discussed.
PMID- 9760741
TI - The Rorschach Schizophrenia Index (SCZI): an examination of reliability,
validity, and diagnostic efficiency.
AB - In this study, we investigate the reliability, validity, and diagnostic
efficiency of the Rorschach Schizophrenia Index (SCZI) in relation to the
accurate identification of patients diagnosed with Diagnostic and Statistical
Manual of Mental Disorders (4th ed. [DSM-IV], American Psychiatric Association,
1994) schizophrenia or other psychotic disorder (PD) according to the
methodological recommendations offered by Wood, Nezworski, and Stejskal (1996).
Seventy-eight patients who were found to meet DSM-IV criteria for a PD or Axis II
disorder (PD = 33; borderline personality disorder = 23; Cluster A personality
disorders = 9; Cluster C personality disorders = 13) and 50 nonclinical
participants were compared on the SCZI. The results of this study indicate that
the SCZI is internally consistent and can be reliably scored. In addition, the
SCZI was used effectively in differentiating PD patients from patients with an
Axis II disorder and from the participants in the nonclinical sample. Also, the
SCZI variable was found to be empirically related to the presence of a DSM-IV
diagnosis of PD. Finally, this variable could be employed for classification
purposes in ways that were clinically meaningful in the diagnosis of a PD.
Conceptual and methodological issues are discussed in relation to the assessment
of psychosis.
PMID- 9760742
TI - Cognitive and affective representations of people and MCMI-II personality
psychopathology.
AB - Hibbard, Hilsenroth, Hibbard, and Nash (1995) found that affective, but not
cognitive, dimensions of object representations were related to the severity of
psychopathology among outpatients. In this study, the Social Cognition and Object
Relations Scale (Western, Barends, Leigh, Mendel, & Silbert, 1990) developed for
interview data (Relationship Episodes; Luborsky, 1990) was used to assess the
object representations of 33 men and 38 women entering psychotherapy. The Millon
Clinical Multiaxial Inventory-II was used to assess the personality traits of the
71 participants. The results support earlier findings that only affective
dimensions of object representations are related to outpatient personality
pathology.
PMID- 9760743
TI - A new perspective on gender orientation measurement with the MMPI-2: development
of the Masculine-Feminine Pathology Scale.
AB - A new scale of gender orientation for the MMPI-2 (Minnesota Multiphasic
Personality Inventory-II; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989)
called the Masculine-Feminine Pathology Scale, or Mfp, was developed as an
alternative to the available Mf, GM, and GF scales. It differs from previous
scales in its emphasis on symptomatic correlates of gender. Items were included
in the new scale if they (a) discriminated between male and female psychiatric
patients and (b) were likely to be indicators of psychopathology. Statistical
analyses suggested an acceptably reliable but factorially complex scale. When
used to predict clinician ratings of global psychopathology, the scale
demonstrated incremental validity over both the existing gender-related scales
and the traditional clinical scales. Scores at the "feminine" end of the Mfp
scale seem to reflect distress characterized by high levels of anxiety. Scores at
the "masculine" end of the Mfp scale suggest a more composed interpersonal
presentation, which may reflect an amoral attitude. It is suggested that the new
scale may prove superior to the existing gender role scales as a supplement to
other clinical scales. Avenues for future research with the Mfp scale are
discussed.
PMID- 9760744
TI - Self-concept in children: equivalence of measurement and structure across gender
and grade of Harter's Self-Perception Profile for Children.
AB - In this study, we tested a Dutch version of Harter's (1985) Self-Perception
Profile for Children for equivalence of measurement and structure across gender
and age (grade), using the LISREL confirmatory factor analytic model. The sample
consisted of 758 Flemish 4th, 5th, and 6th graders (8-13 years old, M = 10.5
years old). Support was found for equivalence of structure for boys and girls,
for 4th and 5th graders, and for 5th and 6th graders. Equivalence of measurement
was only partially found. The relation between items and factors was invariant
across gender and grade. The error of measurement however was not equivalent,
indicating that the items had not the same reliability for boys and girls and
across all grade groups.
PMID- 9760746
TI - Influence of temperature, pH and water activity on "in vitro" inhibition of
Penicillium glabrum (Wehmer) Westling by yeasts.
AB - Four different yeast species (Metschnikowia pulcherrima, Saccharomycopsis vini,
Kluyveromyces marxianus, Cryptococcus albidus), isolated from surface of grapes,
were evaluated for biocontrol potential against Penicillium glabrum. In order to
investigate the influence of temperature, pH, water activity and yeast cell
concentration on Penicillium glabrum inhibition, the individual effects and the
interaction of these factors were analyzed by means of a Central Composite Design
(CCD). All yeast species tested showed antagonistic effects which were more
pronounced at high cell concentrations. The other variables affected the
antagonistic effect differentially depending on the yeast species. Results of the
experimental design showed that the selective success of a competitive microflora
is under environmental control; moreover, when microbial cells are subjected to
multiple factors, the effects and the reciprocal interactions of the individual
variables cannot be independently evaluated.
PMID- 9760747
TI - Hansenula anomala as spoilage agent of cream-filled cakes.
AB - The aims of this work were to identify the causal agents of the sporadic off
odour occurrence in Italian cream-filled cakes and to investigate the yeasts
associated to various ingredients as well as the final products. In the overall
production of the considered confectionery, the phenomenon was linked to a
specific type of filled-cake such as the one having the hazel nut pastry as an
ingredient. This ingredient as well as the final products were characterized by
high frequencies of the spoilage yeast Hansenula anomala. This species, due to
attributes such as osmotolerance and the ability to produce high concentration of
ethyl acetate, could exercise a decisive role in the occurrence of the off
flavour.
PMID- 9760749
TI - Purification and characterization of four catechol 1,2-dioxygenase isozymes from
the benzamide-assimilating bacterium Arthrobacter species BA-5-17.
AB - When Arthrobacter sp. BA-5-17 was grown on benzamide, the bacterium synthesized
four different catechol 1,2-dioxygenase (CD, EC 1.13.11.1) isozymes (CD-I, II,
III-1, and III-2). We purified each CD to homogeneity by a series of column
chromatography. The molecular masses of the four CDs were between 68 and 72 kDa.
The enzymes were made up of two identical subunits each with the molecular mass
of 33 kDa. CD-I and II were indistinguishable in enzymatic properties tested.
Most properties of CD-III-1 were similar to those of CD-III-2. However, CD-III-1
had a marked adsorption peak at 325 nm, which disappeared in CD-III-2 as well as
in CD-I and II. CD-III-1 and III-2 were much more resistant to heating and
inhibitors than CD-I and II.
PMID- 9760750
TI - The low level expression of chloramphenicol acetyltransferase (CAT) mRNA in
Escherichia coli is not dependent on either Shine-Dalgarno or the downstream
boxes in the CAT gene.
AB - Recent studies have shown that the canonical Shine-Dalgarno (SD)-anti-SD
interaction is dispensable for the initiation of translation of certain mRNAs in
Escherichia coli. Alternative non-SD sequences (located upstream from the
initiation codon) and also downstream sequences ("downstream boxes")
complementary to 16S rRNA were found to be involved in the initiation of
translation of mRNAs devoid of either SD or any leader sequences. In this study
the chloramphenicol acetyltransferase (CAT) gene was modified to remove the 5'
terminal non-translated region and/or the two potential downstream boxes in the
CAT gene. Thus a series of ten CAT gene constructs was created and expressed in
E. coli under a strong constitutive promoter. The results showed that CAT mRNAs
devoid of both leader sequence nucleotides and the two downstream boxes in the
CAT gene remained active in vivo and produced CAT protein in sufficient amounts
for survival of the transformed cells at chloramphenicol concentrations up to 20
30 micrograms/ml.
PMID- 9760751
TI - Polyamine metabolism in Saccharomyces cerevisiae exposed to ethanol.
AB - Growth of the yeast Saccharomyces cerevisiae was unaffected by up to 24 h
exposure to ethanol concentrations ranging from 1% to 9%, but was reduced
following exposure to 12% ethanol. Concentrations of the polyamines putrescine,
cadaverine and spermidine were not affected by a 24 h exposure to 12% ethanol,
although there was a significant increase in spermine level. These changes were
accompanied by significant increases in the activities of the polyamine
biosynthetic enzymes ornithine decarboxylase (ODC) and S-adenosylmethionine
decarboxylase (AdoMetDC) and in the flux of label from ornithine into the
polyamines. Formation of the cadaverine derivatives aminopropylcadaverine and N,N
bis(3-aminopropyl)cadaverine was greatly increased in yeast exposed to 12%
ethanol for 24 h, probably via the action of ODC, AdoMetDC and the
aminopropyltransferases. Exposure to 12% ethanol also led to substantial
reductions in the uptake of putrescine and spermidine and the amino acid
methionine.
PMID- 9760752
TI - [Workshop meeting of the German Pharmaceutical Society. 10-12 March 1997.
Abstract].
PMID- 9760753
TI - National Scientific Medical Meeting. 27-28 March 1998. Abstracts.
PMID- 9760754
TI - [XV National Congress of the Spanish Society of Parenteral and Enteral Nutrition.
Alicante, 13-15 May 1998. Abstracts].
PMID- 9760755
TI - [6th Congress of the Union of Swiss Surgical Societies. Lausanne, Switzerland, 24
27 June 1998. Abstracts].
PMID- 9760756
TI - 1998 Receptor and ion channel nomenclature.
PMID- 9760757
TI - [Another look at the AIDS virus].
PMID- 9760758
TI - [Therapeutic approach to acute myeloid leukemia].
AB - The treatment of acute myeloid leukemia has evolved considerably over the past
decade. While induction therapy appears to have been almost standardized, there
continues to be an ongoing debate and controversy regarding the best form of post
remission therapy. Attempts are being made to identify patients at particular
risk of relapse to enable appropriate selection of best induction and post
remission therapies. In these respects, cytogenetics are useful. New concepts
include the use of growth factors, immunotherapy, MDR modulation and therapies
evolving from a better knowledge of the anomalies of the genes that cause
leukemia.
PMID- 9760759
TI - [Intestinal transplantation: a clinical reality in 1998].
AB - Each year, thousands of peoples die, suffering from an anatomical or functional
loss of their intestine; these patients would benefit from bowel transplantation;
the difficulties of bowel transplantation are as follows: 1. the physiological
characteristics of the small bowel, and the fact that denervation, lymphatics
interruption and ischemia, independently from rejection, may disturb its
function; 2. secondly, the organ is septic; thus, its transplantation causes
major infectious problems; 3. at last, the immunological characteristics of the
intestinal allograft. Bowel transplantation causes a two-way immunological
conflict, not only a standard rejection response, but also a graft-versus-host
disease, similar to that observed after bone marrow transplantation; this
reaction is caused by the lymphoid tissue conveyed within the bowel graft. The
introduction of a new immunosuppressive molecule, FK 506, in combination with
profound antibiotic prophylactic regimens, decontamination protocols and vigorous
anti-viral protection (against cytomegalovirus and Epstein-Barr), have
significantly improved the results. Bowel transplantation has recently reached
clinical application. The one-year survival rate of intestinal grafts reaches now
70%. Still, there is no doubt that, due to its microbiological and immunological
characteristics, the small bowel will remain the most challenging abdominal organ
to transplant.
PMID- 9760761
TI - [Evidence of new diagnostic and prognostic human astrocytoma tumor markers.
Potential therapeutic applications. I].
AB - This paper summarises different studies of our group whose aim to improve the
accuracy of prognostic values for patients with astrocytic tumors. Our approach
aims to optimise the conventional evaluation of astrocytic tumor malignancy by
means of the quantification of conventional morphological criteria, and the
production of biological variables related to DNA ploidy level. All these
quantitative variables have been generated by means of computer-assisted
microscopy and submitted to adapted data analysis methods. A series of 250
astrocytic tumors has been analysed, including 39 astrocytomas (AST), 47
anaplastic astrocytomas (ANA) and 164 glioblastomas (GBM) identified in
accordance with the WHO classification. This classification distinguishes between
tumor groups with relatively (AST), intermediary (ANA) and unfavorable (GBM)
prognoses. However, it does not take into account the high degree of
heterogeneity in each tumor group and may thus be poorly for individual case
prediction. In this context, our approach has been able to identify new entities
in the AST and ANA histological groups. These entities have established some
reference points on the biological continuum according to the sequence AST-->ANA-
>GBM and enable prognosis evaluation to be improved in astrocytic tumors.
PMID- 9760762
TI - [Evidence of new diagnostic and prognostic human astrocytoma tumor markers.
Potential therapeutic applications. II].
AB - Human astrocytic tumors grow into the normal brain parenchyma either as localized
tumors, or as highly diffuse neoplasms. The diffuse phenotype relates to a
specific sub-type of neoplastic astrocytes with a high motility and invasion
capacity. Motility features refer to locomotion while invasion features refer to
protease secretion. Our data reveal that several peptides belonging to the
gastrin/cholecystokinin peptide class are able to significantly (and in certain
cases very significantly) modify the level of tumor growth (at the level of cell
proliferation and/or cell death), of motility and of invasion in various
experimental models of human astrocytic tumors. We are synthesizing various
gastrin/cholecystokinin-related peptides in order to develop clinical
applications with which we want to inhibit astrocytic tumor growth, individual
neoplastic astrocytic motility and the invasion of the normal brain parenchyma.
PMID- 9760763
TI - [Chromosome sensitivity to bleomycin-induced damage in patients with laryngeal
cancer as a marker of genetic risk].
AB - An inter-individual variability in sensitivity to mutagen-induced genotoxicity
was studied in respect to an estimation of larynx cancer risk. Bleomycin induced
chromosome breaks were analysed in blood lymphocytes proliferating in vitro in a
group of 35 larynx cancer subjects and in 18 healthy controls. A significantly
higher index of chromosome breaks was found in larynx cancer subjects as compared
with the controls. The distribution of individual results indicates that subjects
oversensitive to bleomycine were identified only among laryngeal tumour patients.
A potential usage of bleomycin test in tumour prognosis is discussed.
PMID- 9760764
TI - [Surgical treatment of hypopharyngeal cancer: reconstructive methods].
AB - The paper presents a 26-year experience of the ENT Clinic of the Pomeranian
Medical Academy in Szczecin with 20 patients who underwent reconstruction of the
hypopharynx after resection for locally advanced carcinoma. The procedures were
carried out in years 1970-1995. The reconstructions included 7 musculomucosal
pedicle flaps obtained from the base of the tongue, 5 epiglottis pedicle flaps, 4
tubed pectoralis major musculocutaneous flaps, 1 vascular pedicle submandibular
gland flap, 1 deltopectoral flap, 1 skin flap and 1 island pectoralis major
musculocutaneous flap. An analysis of the procedures with emphasis on the
oncological and functional results indicates that each techniques has advantages
in specific circumstances. Guidelines for the application of the techniques are
described.
PMID- 9760765
TI - [The results of surgical treatment of patients with laryngeal carcinoma in years
1988-1989 in four departments of otorhinolaryngology].
AB - In a group of 579 patients with laryngeal carcinoma treated surgically in years
1988-1989 in four departments of otorhinolaryngology of the Medical Academies in
Poznan, Warsaw, Cracow and Lublin, 72% survived 3 years without recurrence and
59% survived 5 years. Similar results were obtained in years 1986-1987. The
authors discuss in detail the reasons for failures of the surgical treatment,
i.e.: supraglottic localization of the cancer, its extensiveness in the larynx,
the stage of clinical development, general condition of the patient,
effectiveness of the operation, regularity of postsurgical examination, the
degree of histological malignancy, blood transfusion during the operation,
distant metastases, little efficiency of medical service in early diagnosis of
laryngeal cancer, avoiding postsurgical radiation, subjective factors of the
patients and the choice of the optimal method of the treatment. Few patients can
be cured if the initial treatment fails.
PMID- 9760766
TI - [On fronto-anterior reconstructive laryngectomy].
AB - The paper describes improved fronto-anterior reconstructive laryngectomy using
liberated specifically pediculated and lowered glottis to replace the removed
anterior segment of the thyroid cartilage. The very technique as well as its
advantages are discussed. The main advantage of the method is that it makes use
of the pediculates, well vasculated glottal cartilage covered with cilliar
epithelium preserving the physiological direction of the cilliar movement. The
cartillage is significantly thicker than the free nasal septum cartilage
transplant used until recently. Post-operative discomfort is manifested by
temporary difficulties in swallowing connected with the covered glottis. The
procedure is technically uncomplicated, the vasculated cartilage heals very well
and the respiratory and phoniatric effects are satisfactory.
PMID- 9760767
TI - [Therapeutic effectiveness of Cedax in the treatment of selected acute upper
respiratory diseases].
AB - A group of 66 patients with acute inflammatory upper respiratory tract diseases
were examined in the ENT Department of Poznan Medical Academy between November
1996 and November 1997. Specimens for bacteriological cultures were collected
from the ear, nose and throat. The subjects were treated with ceftibuten.
Clinical improvement was reported in all cases. In 44 patients, ceftibuten
treatment eliminated pathogenic bacteria (as evidenced by microbiological
analysis).
PMID- 9760768
TI - [The role of imperfect fungi in etiopathogenesis of allergic rhinitis].
AB - In this paper the role of imperfect fungi in etiopathogenesis of perennial
rhinitis was examined. In a group of 26 patients the concentration of total IgE
and IgE specific of Candida albicans, Aspergillus fumigatus, Alternaria
alternata, Mucor racemosus and Cladosporum herbarum was signified.
Oversensibility to imperfect fungi was confirmed in 30.8% of patients: to Candida
albicans in 3.8%, to Aspergillus fumigatus in 11.5%, to Alternaria alternata in
3.8%, to Mucor racemosus in 7.6% and to Cladosporum herbarum in 3.8%.
PMID- 9760769
TI - [Efficiency evaluation of radiotherapy of recurrences after surgery in head and
neck cancer].
AB - An analysis of 200 consecutive patients with head and neck squamous cell cancer
treated after surgery with radiation at the Centre of Oncology, Maria Sklodowska
Curie Memorial Institute in Gliwice was performed. At the beginning of
radiotherapy recurrences were found in 67 (33.5%) patients. Recurrences were
diagnosed at the primary site exclusively in 30 patients, in lymph nodes only in
21 patients, in both localizations in 14 patients, and in 2 patients in the
tracheostomy. Conventional 60Co radiation treatment to the mean total dose of
62.5 Gy was applied. Three year disease-free survival probability was 22% for
patients with recurrences comparing to 54% for patients with no relapse. In the
group of patients with recurrences better prognosis was found for patients with
preoperatively early stages, and with early recurrences, located in the primary
tumour site, which completely responded to radiotherapy. High rate of recurrences
after surgery for head and neck cancer and low probability of recurrence control
with radiotherapy indicate the necessity of more careful qualification for
surgical treatment.
PMID- 9760770
TI - [Correlations between topography of the main structures of the temporal bone and
the location of the sigmoid sinus].
AB - Topographical relations between main structures of the temporal bone are
important for otosurgeons. There were reports aiming at establishing some laws in
the temporal bone building, that would allow to anticipate the location of the
important structures in the temporal bone. It is obvious nowadays that precise
and absolute rules do not exist. In the present study the aim was to estimate if
there are statistically significant correlations between some dimensional
parameters of the temporal bone. It was stated that the smaller the distance
between the sigmoid sinus and the external auditory meatus, the higher the
jugular bulb is situated. Coefficient in this correlation was 0.46. However, no
correlation was found between the location of the sigmoid sinus and the facial
nerve on one hand and the internal carotid artery on the other. It is important
for otosurgeons to know that the prominent sigmoid sinus does not determine
existence of a narrow facial recess.
PMID- 9760771
TI - [Histological and histochemical investigation of pathological laryngeal mucosa
with papillomatosis in children and adults].
AB - Papillomas of the larynx are the subject of numerous studies. They occur in two
forms (multiple and singular). The authors presented the results of histological
and histochemical investigations of larynx papillomas in 9 adults and 16
children. The studies comprised patients treated in the Clinic of Otolaryngology
in Wroclaw. Surgically removed lesions constituted the material for estimation.
Peculiar attention was paid to the degree of differentiation of tumours under the
microscope. The interdependence between intensification of reaction and degree of
epithelhyperplasia and strict connection of intensification of reaction with
quantity of dysplastic changes of epithelium were indicated by estimation of
enzymatic reactions. Histological studies disclosed marked morphological
differences between papillomas in children and adults. The correlation of
reactions to lactic dehydrogenase and NADH2-tetrazole reductase can be treated as
an expression of hyperplastic changes in the epithelium. What is more, the
reaction to lactic dehydrogenase may be regarded as a metabolic index of
malignancy.
PMID- 9760772
TI - [The role of human papillomavirus (HPV) infection in the pathogenesis of the
laryngeal cancer].
AB - In the paper the role of virus infection in carcinogenesis was presented.
Particular significance of human papillomavirus infection in the neoplastic
diseases, also in the laryngeal cancer was emphasized.
PMID- 9760773
TI - [Issues in total reconstruction of the auricle in microtia].
AB - The author's personal experience with 83 cases of auricular construction is
presented, as well as methods that have evolved through the last 3 decades. The
details of reconstructive procedure are discussed. Advisability of external ear
reconstruction in unilateral microtia is evaluated. The follow-up ranges from 2
to over 20 years. Major complications occurred in only 3% of cases and were
limited to the perioperative period. The significance of the emotional and
psychological benefits of the operation is emphasized. Photographic evidence is
presented, too.
PMID- 9760774
TI - [The use of the ox's vein for myringotomy of the ear].
AB - The study presents a modification of the method developed by Zini et al. to
prepare an ox's vein for a myringoplasty. The graft of the vein was pickled in a
trypsin solution, fixed in formaldehyde and stored in a 70% ethanol solution. It
was established that the incubation period of the vein in the trypsin solution
required to produce the best histological specimens for this purpose was 5 hours.
The preparation of the ox vein for a graft with the use of trypsin is relatively
simple and inexpensive. Xenografts of ox veins for use in myringoplasties in
humans are a good material and may be successfully used both in reconstructions
of large defects in the tympanic membrane and in operations to correct congenital
atresia of the ear.
PMID- 9760775
TI - [Diagnostic problems in coexistence of paranasal sinusitis with cerebral tumor].
AB - Differential diagnosis between the intracranial complications of paranasal
sinusitis and cerebral tumor belongs to very difficult tasks in otolaryngology
and neurosurgery. Complications of sinusitis, such as intracranial abscess
formation, are uncommon and often clinically unremarkable. The arising
difficulties are even greater in inflammatory intracranial complications of
sinusitis, giving symptoms similar to those of cerebral tumors. The illustrative
case report was presented.
PMID- 9760776
TI - [Mast cells in eosinophilic and neutrophilic nasal polyps. Cytological and
histological examinations].
AB - In 10 patients with nasal polyps mast cells were counted in smears and in polyp
tissues. In smears from neutrophilic polyps (n = 4) no mast cells were found, in
eosynophilic polyps (n = 6) mast cells were found on an average of 7.5%.
Histological examinations showed that an average number of mast cells in the
connective tissue was similar in both types of polyps. In the epithelial layer of
neutrophilic polyps the number of mast cells was slightly greater than in
eosynophilic polyps. In an atopic patient the number was 12 times greater than in
the other cases. No dependence was found between the number of mast cells in
smears and in the tissue.
PMID- 9760777
TI - [Acoustic rhinometry in the assessment of the topical treatment of upper
respiratory infections with fusafungin].
AB - The aim of the study was to estimate by means of acoustic rhinometry (AR) the
nasal blockade in 37 patients (5-73 years old, mean 32) with upper airways
infections treated by fusafungine. The examinations were carried out on the first
(D1) and seventh day (D7) of observation. Cross-sectional area (CA) mean values
of 3 cm sector laid back to C notch of AR curves (CA-C3) were selected to the
analysis. RESULTS: The mean value of CA-C3: in all patients it was 2.61 cm2 on D1
and 2.8 cm2 on D7; in rhinitis and sinusitis patients--2.23 cm2, in others--3.16
cm2; without nasal discharge--3.48 cm2, in others (with severe or medium)--2.53
cm2 and 2.48 cm2 respectively. 29 patients had nasal blockade (78.4%) with mean
CA-C3 = 2.34 cm2 (others--3.56, p < 0.05). During seven days the following
enlargement of CA-C3 was reported: 14.9% in all patients (p < 0.01); in viral
infections 24% (n = 14, p < 0.01), bacterial 14.3% (n = 11, NI); in nasal
blockade patients--15.22%, others--13.55% (p < 0.01). Mean value of CA-C3
increased by 37.7% in patients who demonstrated, according to the physicians,
"very good improvement", 5.7%--"good", 1.5%--"weak" (p < 0.05). There was also
enlargement of nasal cavities in CA-C3 in non-sneezers (p < 0.05) and medium
discharge symptom patients (p < 0.05). There was no statistical difference in
clinical and acoustic rhinometry results between patients treated with
fusafungine together with non-steroid anti-inflammatory drugs and patients
treated with fusafungine. CONCLUSION: AR is a good instrument to be used in the
objective assessment of the nasal blockade changes in people with infection of
the nasal mucosa and showed positive efficacy of fusafungine in the treatment of
upper airway infection.
PMID- 9760778
TI - [On the frequency of Meniere's disease occurrence].
AB - The authors estimated the frequency of Meniere's disease occurrence among
patients of Department of Otolaryngology, University School of Medicine in Lodz
in years 1986-1995. The incidence of Meniere's disease was evaluated as 0.46% of
all clinic patients and as 1.7% of cases which were treated for aural diseases.
Diagnosis was made on the basis of clinical symptomatology, exact medical
examination and audiologic tests. The function of vestibular organs was assessed
with the help of caloric tests with ENG recordings. Meniere's disease incidence
has been the subject of many epidemiological papers in literature but the exact
values are different. Perhaps it can be attributed to a variety of criteria
applied in defining Meniere's disease or to epidemiological differences.
PMID- 9760779
TI - [Juliusz Lempert (1890-1959): the author of the fenestration technique].
AB - Juliusz Lempert was born in 1890 in Poland. A few years later the poor Jewish
family emigrated to the United States. Lempert obtained his MD degree at Long
Island Medical College, and soon after that established a small hospital of his
own in Manhattan. Later he bought an old five-storey building and converted it
into a new otological medical center, which he called Endaural Hospital. His life
was rather difficult with the wave of antisemitism in the United States and the
adversity which he encountered so many times. However his contribution to the
microsurgical treatment of conductive deafness is immense. He elaborated and
introduced a new method of mastoidectomy and, first of all, fenestration--a new
one-stage surgical technique to be applied in cases of otosclerosis. This
precise, sophisticated operation revolutionized surgical treatment. With a
dentist's drill Lempert created a new window on the horizontal canal, in this way
the sound wave could stimulate the inner ear. He was to call it "fenestration nov
ovalis". Lempert was never a member of any ENT society and worked in his hospital
alone. When suddenly his only son was stricken with leukemia and died, Lempert
was completely broken, and never returned to this work. The next blows were new
operative methods of otosclerosis: stapes mobilisation introduced by Rosen and
stapedectomy by Shea. He never accepted these new techniques. It was a painful
experience for a surgical genius who had at so many times been hurt during his
life. He could not believe that his fenestration was definitely gone. Lempert
quickly deteriorated physically and mentally, and died in 1958.
PMID- 9760780
TI - [Voice function after chordectomy in patients with larynx carcinoma].
AB - The quality of voice was examined in 18 patients with larynx carcinoma before and
after chordectomy. Subjective and objective (spectrographic) methods were
applied. The larynx was examined in indirect laryngoscopy and videostroboscopy.
Significant voice pathology was found in patients before surgery when compared
with norm. Early phoniatric rehabilitation helped to achieve subjective
improvement of voice quality in patients after surgery.
PMID- 9760781
TI - [A rare case of multiple primary malignant neoplasms of parotid gland:
fibrosarcoma and squamous cell carcinoma].
AB - Primary multiple malignant neoplasms and multifocal neoplasms are a very complex
problem and therefore have been a topic of many articles. The mechanism of
origin, frequency of occurrence, co-existence of neoplasms in functionally
similar organs (uterus, mammary gland), heredity, a possibility of diagnostic and
therapy are the most interesting aspects. Frequency of multiple primary malignant
neoplasms occurrence is about 2-8% and still increases. Pathogenesis of
multifocal and multiple neoplasms has rarely been a subject of articles. A
simultaneous exposure of a tissue to damaging factors and special tissue
sensitivity are the main reasons for neoplasms origin in this group. The authors
present a rare case of parotid gland multiple neoplasm: fibrosarcoma and squamous
cell carcinoma, as well as discuss the diagnostics, therapy, and prognosis of
multiple neoplasms.
PMID- 9760782
TI - [Myxoedema after radiotherapy of the laryngeal cancer].
AB - In a 49-year-old woman carcinoma planoepithelialie akeratodes of the right vocal
cord was diagnosed. The lesion was removed with the Kleinasser's microsurgery
procedure. During telecobaltotherapy, temporary oedema of the face and the neck
as well as dysphagia appeared. Myxoedema due to insufficiency of the thyroid was
diagnosed after four months since the end of the radiotherapy. Substitutional
treatment resulted in the hormonal and clinical improvement of the patient.
PMID- 9760783
TI - [Selected etiological factors in the pathogenesis of subglottic laryngitis in
children].
PMID- 9760784
TI - [Evaluation of changes in the course of seasonal allergic nasal mucosa
inflammation].
PMID- 9760785
TI - [The rehabilitation program for the patients after cochlear implantation].
PMID- 9760786
TI - [Respiratory tract symptoms in school children exposed to indoor and outdoor air
pollution].
AB - The epidemiologic study has been carried out in 1129 nine-year old schoolchildren
in 4 city areas of Krakow, which differed in air pollution levels. Indoor air
quality was assessed by the presence of the environmental tobacco smoke, type of
domestic heating and the presence of molds or dampness on the walls. The
occurrence of two or more respiratory symptoms (chronic cough, chronic phlegm,
wheezing, dyspnea attacks, breathlessness or hay fever) was associated
significantly with the outdoor air pollution score (chi 2 for trend = 13.315,
df:1, p = .0000), with molds/dampness on the walls (OR = 2.16, 95% CI: 1.45-3.22)
and allergy in children (OR = 5.94, 95% CI: 4.12-8.59). Since the results have
shown the significant relationship between allergy and outdoor air pollution as
well, the study confirms that outdoor pollutants increase the risk of allergic
sensitization of young children.
PMID- 9760787
TI - [Usefulness of cryoapplication for bleeding after needle biopsy during fiberoptic
bronchoscopy].
AB - The protective role of superficial freezing (using a "spray" N2O cryoprobe) of
tracheobronchial tumours before fiberoptic biopsy was evaluated in 21 patients
with suspected lung cancer and high risk of bleeding. An excellent haemostatic
effect was observed in all but two patients despite 3-9 specimens taken into
histopathological examination. No serious complications besides a transient cough
in 5 patients were observed. So a new "spray" type cryoprobe was found useful in
protection against bleeding during bronchoscopy without negative influence on the
histopathological confirmation of malignancy.
PMID- 9760788
TI - [Evaluation of angiogenic activity in sera from patients with interstitial lung
diseases].
AB - Angiogenesis is a process of new blood vessels' formation occurring in many
physiological and pathological conditions. Neovascularisation is the principal
vascular response in chronic inflammation and concomitant fibrotic process.
Microvascular changes in various organ sites in sarcoidosis (BBS) and some of the
symptoms of the disease may be related to microangiopathy. Moreover, vascular
alterations were also observed in lung specimens from idiopathic pulmonary
fibrosis (IPF) and avian fanciers lung (AFL) patients. The present study was
aimed at testing the effects of serum from 43 patients with ILD (24 BBS, 8 AFL, 8
IPF, 3 DIPF--drug induced pulmonary fibrosis) and 11 healthy controls on
angiogenic capability of normal blood peripheral mononuclear cells (PBMC) in the
murine intradermal angiogenesis assay (according to Sidky and Auerbach). The data
demonstrated that sera from ILD patients significantly enhanced angiogenic
capacity of normal PBMC as compared to control sera (p < 0.001). The effect was
more pronounced for AFL patients than for BBS and IPF ones (p < 0.05). Sera from
DIPF did not stimulate angiogenesis compared to control sera. The data showed
that sera from ILD patients constitute sources of mediators participating in
angiogenesis. This phenomenon may play role in pathogenesis of chronic
immunological processes in lung.
PMID- 9760789
TI - [Complications after BCG vaccination in the urban section of Lodz in the years
1994-5].
AB - The purpose of this paper was to evaluate the incidence of complications after
BCG vaccination in children from urban area of Lodz in 1994-1995 and to give
their pathological and prognostic interpretation on the basis of immunological
and Groer allergometric examinations. The obtained data demonstrate that
postvaccinal complications occurred in 46 children, that is 0.7/1000 of
vaccinated population. They were observed mainly in newborns (45.7%), whereas
they were particularly rare in revaccinated six-year-old children (13%) and
schoolchildren (8.7%). In half of the cases there was an evidence of ulceration
and suppuration in the site of vaccination, in another half--suppuration of local
lymph nodes with or without fistula. Immunological and allergometric examinations
were carried out in 21 children with post-vaccinal complications and 21 children
with normal post-vaccinal period. In both groups the following were the subjects
of evaluation: values of B and T lymphocytes and their CD4 and CD8
subpopulations, lymphocytes proliferative response to mitogenic PHA doses and
tuberculin, as well as IgG, IgA and IgM levels. Immunological and allergometric
examinations indicated that immunosuppression was neither the cause nor the
effect of BCG complications.
PMID- 9760790
TI - [Staphylococcal pneumonia--analysis of material from patients treated at the
Hospital for Lung Diseases in the years 1981-1994].
AB - Retrospective analysis of staphylococcal pneumonia was made in 182 patients, aged
18-88 years /61% more than 60 years old/ treated in hospital in years 1981-1994.
Majority of these patients had various concomitant diseases, mostly chronic
bronchitis and lung cancer. Strains of Staphylococcus aureus were sensitive
mainly to amoxycillin--clavulanic acid, roxitromycin, amikacin, netilmicin,
clindamycin, cefamandol, chloramphenicol, rifampicin and resistant mostly to
penicillin /90% of strains/, ampicillin, tetracyclines. In many cases initial
antibacterial treatment was inadequate in relation to sensitivity pattern of
staphylococci--hence many changes of antibiotics were observed in the course of
the therapy. Newer antistaphylococcal drugs were applied only in the last years
of the study. Despite these therapeutical drawback outcome of staphylococcal
pneumonia was good in 85% of patients; 14% of patients died /mainly as a
consequence of comorbidities/. Successful therapy of staphylococcal pneumonia
requires early recognition of possibility of infection due to Staphylococcus
aureus and adjustment of drugs to probable or actual sensitivity of these
pathogens.
PMID- 9760791
TI - [The effect of nedocromil sodium on spontaneous production of histamine releasing
factor (HRF) by mononuclear blood cells in patients with nonatopic bronchial
asthma].
AB - The aim of the study was to evaluate the effect of 28-days antiinflammatory
treatment with nedocromil sodium (Ned.sod.) (Tilade-8 mg/24 hours) on nonspecific
bronchial hyperreactivity (PC20H in mg/ml) and spontaneous HRF activity
production by mononuclear blood cells in patients with nonatopic bronchial asthma
treated with beclomethasone dipropionate. The correlation between PC20H and HRF
was also examined. The study was performed in 10 subjects with mild and moderate
chronic, stable asthma in a double-blind, placebo-controlled way. Placebo and
Ned. sod were given through 4 weeks in a randomized way with 8 weeks wash-out
period. It was shown that Ned. sod. did not influence clinical asthma symptom
scores, ventilatory parameters and PC20H. No changes in the spontaneous
production of HRF activity were observed. The correlation between HRF activity
and PC20H assessed 4 times was not significant. The authors conclude that studies
with Ned. sod. in nonatopic asthma should be continued, but the dosage of the
drug ought to be bigger and the time of treatment should to be longer.
PMID- 9760792
TI - [Clinical evaluation of side effects during immunotherapy with Catalet T in
patients with hay fever].
AB - The aim of this study was to evaluate the frequency of side effects during
specific immunotherapy with Catalet T and to compare the frequency of side
effects between different groups of patients according to time of immunotherapy
continuation (from 1 to 5 years). The study was carried on 100 patients aged from
12 to 58 years. The tolerance of Catalet was good. 83% of investigated patients
finished the immunotherapy course with minimal or no side effects. The prevalence
of side effects was the same independently from the time of immunotherapy.
PMID- 9760793
TI - [Evaluation of the efficacy of nebulized salbutamol in exacerbation of chronic
asthma].
AB - The aim of the study was to evaluate the influence of nebulized salbutamol in low
doses (0.5 mg, 1 mg, 1.5 mg) on lung function in patients with acute severe
asthma. The study was performed in 30 patients--22 female and 8 male. Nebulized
salbutamol proved to be an effective bronchodilating drug which enables to
control exacerbations in asthmatic patients receiving conventional medical
treatment. The evaluation of effect of nebulized salbutamol should take into
account both subjective symptoms and (basic) spirometry parameters of airway
obstruction such as FEV1 PEF. This therapy can improve the efficacy of asthma
management.
PMID- 9760794
TI - [Diagnostic difficulties with detection of foreign bodies from the lower
respiratory tract--late detection].
AB - Five cases of aspirated foreign bodies in bronchial tree were described. The
clinical symptoms did not suggest the real cause of the illness and most of
patients did not remember the fact of foreign body aspiration. The foreign bodies
were removed during bronchofiberoscopy performed in local anaesthesia.
PMID- 9760795
TI - [Estimation of the value of a self-designed questionnaire in diagnosing patients
with suspected obstructive sleep apnea].
AB - We have investigated the use of our own sleep questionnaire as a screening test
for patients suspected of obstructive sleep apnoea (OSA). We examined 156
unselected patients (mean age 49.5 +/- 0.9 years) referred to our clinic because
of snoring or excessive daytime sleepiness. Each subject answered the
questionnaire and underwent full standard polysomonography (PSG). Diagnosis of
OSA, based on PSG, was established when AHI > 10. Significant correlations
between AHI and questionnaire questions were found for BMI (r = 0.54, p < 0.001),
questions considering snoring (r = 0.3, p < 0.001), questions considering apnoeas
during sleep, difficulties with falling asleep and nycturia (r = 0.21, p < 0.01)
and questions asking for dry mouth and tongue in the morning and excessive
daytime sleepiness (r = 0.16, p < 0.05). Sensitivity and specificity of
investigated questionnaire to confirm the disease were: 92% and 38%,
respectively. Evaluated questionnaire helps to select patients with severe form
of OSA demanding quick diagnosis and treatment.
PMID- 9760796
TI - [Hepatic tuberculosis].
AB - Tuberculosis of the liver can be the only manifestation of the disease or it may
be a part of disseminated process. Three cases of liver tuberculosis were
presented. In one of them the process was restricted to the liver and the
diagnosis was made only at autopsy. In two other cases, tuberculosis of the liver
was a part of disseminated process. In one of them the impairment of liver
function improved after therapy and in another one, in spite of therapy, the
patient died with signs of cardio-respiratory and hepatic insufficiency.
PMID- 9760797
TI - [Chronic inflammatory changes in the lung of an 8-year old boy].
AB - A case of pulmonary actinomycosis in the child is described. Firstly, tumor of
lung was suspected. Correct diagnosis was made after thoracotomy and histological
examination of material.
PMID- 9760798
TI - [Evaluation of penetrating heart wounds by echocardiography].
AB - The paper presents a rare case of a penetrating endocardial wound, managed
conservatively, in which echocardiography was used in the serial monitoring.
Heart injuries constitute about 6% of all chest injuries. Because of the
possibility of cardiac tamponade and the massive bleeding into the pleural
cavity, they are life-threatening. In such cases only surgical intervention gives
a chance to save the patient (5). It turns out, however, that patients with
normal echocardiogram and normal vital signs can be managed conservatively, with
echocardiographic monitoring.
PMID- 9760799
TI - [Disruption of the middle bronchus].
AB - Disruption of the middle lobe broncus as a result of blunt chest trauma is
described. Patient underwent emergency reconstructive operation. Follow-up
examination revealed normal postoperative chest radiogram but bronchoscopy showed
decreased patency of bronchial anastomosis. Perfusion lung scintigraphy showed
severely decreased perfusion of the entire right lung. Concomitant fracture of
right clavicle resulted in false joint which required surgical intervention 4
weeks after the chest trauma.
PMID- 9760800
TI - [Behcet's disease with pulmonary vessel involvement].
AB - The case of systemic vasculitis with involvement of pulmonary vessels was
described. 36-years white woman with cerebral vasculitis and recurrent uveitis 5
and 3 years ago, now was admitted to hospital because of the mouth ulceration and
lesions in the chest x-ray. After lung cancer exclusion, aneurysm of pulmonary
artery branch was confirmed by dynamic tomocomputer examination All mentioned
above manifestations were diagnosed as Behcet disease. Patient was treated with
prednison, cyclophosphamide and cyclosporine. Clinical effect was observed after
corticotherapy, but no improvement in chest X-ray picture was obtained also after
immunosuppression. Patient died because of pulmonary haemorrhage 7 years after
first symptoms of vasculitis and 2 years after first massive haemorrhage.
PMID- 9760801
TI - [Pneumonia as a nosocomial infection].
PMID- 9760802
TI - [Lung apex tumor].
PMID- 9760803
TI - [Fibrinolytic treatment of pulmonary embolism].
PMID- 9760804
TI - [The significance of scintigraphic, echocardiographic and electrocardiographic
left atrial transesophageal pacing in diagnosis of ischemic heart disease].
AB - The aim of the study was to compare the perfusion scintigraphy (using SPECT
method with Tc-99-MIBI) during left atrial transoesophageal pacing test (LAPT)
with pacing electrocardiography (ECG), echocardiography (ECHO) and
electrocardiography exercise test (ExT) in ischaemic heart disease (IHD)
diagnostics. The effect of LATP on heart haemodynamic parameters and the
correlation between scintigraphic, echocardiographic and electrocardiographic
parameters during LAPT test have been also assessed. Investigations were carried
out in 55 subjects (Group I: 36 patients with effort angina pectoris; group II:
controls: 19 clinically healthy subjects). Coronarography was performed in 24
patients 6 weeks before or after examinations. LATP test was analyzed with ECG,
ECHO and SPECT. Echocardiography did not increase significantly the LATP test
diagnostic value. Perfusion scintigraphy enhanced sensitivity and predictive
excluding value LATP test. These values were 93.3% v 62.9% and 90% v 59.3%
respectively. LATP test assessed with ECG, ECHO and perfusion scintigraphy
expressed significantly higher sensitivity and predicting excluding value in
comparison to ExT. LATP test analyzed in such way was characterized by 100%
sensitivity and 100% predicting excluding value. CONCLUSION: Combination of LATP
with electrocardiography, echocardiography and SPECT is a non-invasive high
quality method for ischaemic heart disease diagnostics.
PMID- 9760805
TI - [Granulocyte macrophage-colony stimulating factor (GM-CSF) in diagnosis and
monitoring of non-small cell lung cancer].
AB - Serum tumor markers may be helpful in early diagnosis of cancer, in the initial
assessment of the extent of the disease, and in monitoring the tumor growth or
tumor volume reduction once cancer has been diagnosed and treatment started.
Recent studies have focused on a new family of markers -hematopoietic growth
factors, especially on granulocyte-macrophage colony-stimulating factor (GM-CSF).
A number of investigations have shown autologous production of GM-CSF in various
human cell lines derived from melanoma, gastric or ovarian cancer, and in certain
tumors of nonhematopoietic origin. In this study serum level of GM-CSF was
measured using a sensitive sandwich ELISA system in 34 patients with non-small
cell lung cancer (NSCLC) before and 10, 30, 90, 180 and 270 days after surgical
operation. Additionally common accepted tumor markers such as CEA and CYFRA 21.1
were also assayed. Preoperative level of GM-CSF was significantly increased in
cancer patients relative to the normal sera (p < 0.02). Concentration of GM-CSF
and CYFRA 21.1 were decreased on 10th day, but CEA on 30th day after surgical
treatment, although upon comparison of pre- and postoperative tumor markers serum
levels significant difference was observed for CYFRA 21.1 (p < 0.05). Levels of
GM-CSF were increased in 85%, CEA in 62% and CYFRA 21.1 in 51%. The diagnostic
sensitivity and serum levels of GM-CSF were related to the stage of the disease
and the combined use of two markers increased the sensitivity compared with the
use of only one. These results suggest that GM-CSF, especially in the combination
with CYFRA 21.1., may be useful in the diagnostic and monitoring of patients with
NSCLC.
PMID- 9760806
TI - [Polymorphism of the ACE gene and left ventricular morphology and function in
patients with borderline, mild and moderate hypertension].
AB - It has been reported that the allel D of an insertion/deletion (I/D) polymorphism
of the angiotensin I converting enzyme (ACE) gene is associated with the
conditions of increased cardiovascular risk, including the left ventricular
hypertrophy and the dysfunction. We examined the relation between the genotype of
ACE gene and the left ventricular function in normotensives and in borderline,
mild and moderate hypertensives. We investigated 128 subjects, 47 first-diagnosed
untreated hypertensives and 81 normotensives. The M-mode and Doppler
echocardiography were used to quantify LV mass and function. The
insertion/deletion ACE polymorphism was identified using polymerase chain
reaction. Left ventricular indexes of the morphology and function were analyzed.
We compared ambulatory blood pressure profiles between all genotypes in both
groups. There were no significant differences in indexes of the left ventricular
hypertrophy in studied normotensives and borderline to mild hypertensives. Our
results indicate that allel I might be associated with selected parameters of
diastolic function, while allel D with selected parameters of systolic function,
of the left ventricle. Results of this study suggest also probable relation
between allel D and variability of the diastolic arterial pressure in both
investigated groups.
PMID- 9760807
TI - [Combined hemostatic defects in family members of symptomatic carriers of Leiden
mutations of factor V].
AB - The aim of the study was to determine the frequency of additional prothrombotic
defect in family members of 14 symptomatic, heterozygous carriers of factor V
Leiden mutation (FV Leiden). The FV Leiden was found in fifty-five from among 127
persons (43%). Thirty-two from 53 (68%) family carriers of FV Leiden had venous
thromboembolic disease at the time of examination. Combined defects were found in
6 out of 14 families (in 4 families coexistence of FV Leiden mutation with
protein S deficiency, in 1 with G20210 A mutation of prothrombin gene and in 1
with antithrombin III deficiency). Until now 63% (7/11) of combined defect
carriers (mean age 48.5 years) and 59% (24/42) of heterozygous FV Leiden carriers
(mean age 52.2 years) have been symptomatic. The thrombosis-free survival (Kaplan
Maier analysis) was comparable in combined and in single defect carriers groups.
PMID- 9760808
TI - [Erythropoietin in the pathogenesis of anemia in patients with multiple myeloma].
AB - Anemia is a common symptom in multiple myeloma (MM) patients but the pathogenesis
of it is still unknown. The aim of the study was to explain the causes of anemia
in MM patients. Peripheral blood count, bone marrow aspirate, iron and ferritin
level, serum erythropoietin (EPO) level, T cell subsets and in vitro CFU-E count
were analyzed in the group od 31 MM patients. Erythropoietin and iron deficiency
in the study group were not observed. EPO serum level was not significantly
different in patients with multiple myeloma and in comparison to patients with
sideroblastic anemia with solid tumors. Absolute CD8 T lymphocyte count was not
significantly increased in the study group. CFU-E colonies count in vitro was not
decreased in these patients. CONCLUSIONS: In the study group of the MM patients
anemia probably does not depend on EPO production. Diminished proliferative
response of erythropoietic cells on normal serum level of EPO and abnormal iron
utilisation probably occur in these patients. Replacement of normal
erythropoiesis by tumor plasma cells is probably not decisive.
PMID- 9760809
TI - [Surgical treatment of aortic valve disease in patients with severe left
ventricular failure].
AB - Two patients with aortic stenosis and severe left ventricle failure who underwent
aortic valve replacement with satisfactory outcome were presented. Case report.
PMID- 9760810
TI - [Difficulties in distinguishing left ventricular aneurysm from pseudoaneurysm.
Case report].
AB - A case of 51-year old female with large inferior left ventricular aneurysm
developed 3 months after myocardial infarction is presented. The patient
demonstrated advanced congestive heart failure and angina. Coronarography
revealed amputation of the distal part of 3 coronary vessels without possibility
of revascularisation. In ventriculography large inferior wall aneurysm was found.
Echocardiography strongly suggest the presence of pseudoaneurysm. During the
operation very large real aneurysm arising from inferior wall and apex was found.
Postoperative period was complicated by many cardiac and non cardiac events.
Authors discuss the problems of proper diagnostic and its influence on decision
about surgical management.
PMID- 9760811
TI - [Current opinions on the role of hemostatic factors in the pathogenesis of
coronary artery disease].
PMID- 9760812
TI - [Babesiosis-disease of humans and animals].
PMID- 9760813
TI - [Cytokines in multiple myeloma].
PMID- 9760814
TI - [The role of monocyte chemotactic peptide (MCP-1) in chronic renal allograft
rejection].
AB - Monocyte chemotactic peptide-1 (MCP-1) plays a key role as a mediator of
inflammatory infiltration, mainly composed with macrophages. Experimental studies
showed that macrophages and their products are pathogenetic factors of chronic
renal graft rejection (ch.g.r.). The objective of the present study was to
determine the role of MCP-1 in the pathogenesis of human renal ch.g.r. Examined
were 34 patients with ch.g.r. (Group I), 50 patients with a stable allograft
function (Group II), and 25 healthy subjects (control). Serum and urine levels of
MCP-1 were measured by ELISA. The serum level of MCP-1 was found to be higher in
transplant patients, than in control group, but this difference was not
significant. The serum level of MCP-1 showed a correlation with concentration of
triglycerides in both transplant patient groups. This may results from
overproduction of MCP-1 through cells of vascular wall affected by hyperlipidemic
microenvironment. Considering the lack of relationship between the serum and
urine levels of MCP-1, I decided attribute the urine levels of MCP-1 to the
secretion through the infiltrating cells and through the kidney cells. In
patients with ch.g.r. the urine levels of MCP-1 were significantly higher p <
0.001) than in patients with a stable graft function and control group. MCP-1
levels were particularly high (> 2000 pg/mg creatinine) in patients with enhanced
dynamics of ch.g.r. The MCP-1 levels were higher in those patients whose biopsies
described cellular infiltration (1385 + 820 pg/mg creatinine vs 680 + 280 pg/mg
creatinine). The urine level of MCP-1 showed a correlation with concentration of
serum creatinine, cholesterol, level of proteinuria and with arterial pressure in
ch.g.r. patients. Increased urine levels of MCP-1 and correlation of MCP-1 with
the activity of progressive deterioration of the graft function suggest important
role of this chemokine in the pathogenesis of ch.g.r., possibly by activating
macrophages and by stimulating their influx into the vascular wall, glomeruli and
interstitial tissue. Relationship of urinary MCP-1 excretion with arterial
hypertension and lipid disorder suggest that the effect of those risk factors for
a progressive deterioration of graft function manifest on the molecular level by
affecting the generation of MCP-1.
PMID- 9760815
TI - [Levels of 1,25-dihydroxyvitamin D3 concentration in renal venous blood serum of
patients with renovascular hypertension caused by unilateral renal artery
stenosis].
AB - Functionally significant, unilateral renal artery stenosis is characterized by
reduced renal perfusion and lateralization of both excretory and endocrine
function. The present study aimed to assess the influence of unilateral renal
artery stenosis on plasma 1,25-dihydroxyvitamin D3 level. In sixteen patients (10
males and 6 females) with unilateral renovascular hypertension blood samples for
estimation of plasma renin activity (PRA) and 1,25-dihydroxyvitamin D3
concentration were withdrawn from the renal vein of the ischaemic and normal
kidney, from the femoral artery and from the vena cava inferior distally to the
orifices of renal veins. Significantly elevated PRA (20.1 +/- 4.52 ng/ml/h vs 6.0
+/- 1.76 ng/ml/h, p < 0.005) but significantly reduced level of 1,25
dihydroxyvitamin D3 (99.25 +/- 4.8 pmol/l vs 115.75 +/- 6.7 pmol/l, p < 0.05)
were found in renal vein blood of the ischaemic kidney as compared with the
respective values of the normal kidney. No significant correlation was found
between PRA and 1.25-dihydroxyvitamin D3 irrespective of the site of blood
withdrawal. CONCLUSION: Renal ischaemia seems to exert a suppressive effect on
1,25-dihydroxyvitamin D3 synthesis by the kidney.
PMID- 9760816
TI - [Markers of bone formation and resorption in primary and secondary
hyperparathyroidism].
AB - Hyperparathyroidism, both primary and secondary in chronic renal failure, leads
to pathologic changes in the bones. Newly introduced markers of bone metabolism
enable to biochemically detect and evaluate these changes. The aim of our studies
was to perform determinations of serum osteocalcin as a marker of bone formation,
and C-terminal telopeptide of collagen I (ICTP) as a marker of bone resorption in
patients with excessive secretion of parathyroid hormone (PTH). Our studies
comprised of 15 patients with primary and 24 patients with secondary
hyperparathydroidism. In all patients serum PTH, osteocalcin and ICTP were
detected by radioimmunoassay; the correlations between PTH and osteocalcin as
well as between PTH and ICTP were also performed. Serum PTH was elevated in both,
primary and secondary hyperparathyroidism. In primary hyperparathyroidism serum
osteocalcin was moderately or definitely elevated, similarly serum ICTP was high.
Following surgical removal of a parathyroid adenoma, concomitantly with a drop in
serum PTH there was a rapid normalization of serum osteocalcin and ICTP.
Secondary hyperparathyroidism in uraemia was characterised by markedly elevated
serum osteocalcin and ICTP which surpassed the concentration of these markers in
primary hyperparathyroidism. There was a positive correlation between serum PTH
and osteocalcin levels, and a lower correlation between PTH and ICTP. From our
studies it is concluded that excessive secretion of PTH in primary and secondary
hyperparathyroidism stimulates bone formation and to higher degree--bone
resorption.
PMID- 9760817
TI - [The effect of pentoxifylline on oxidative metabolism in neutrophils primed with
tumor necrosis factor alpha in patients with stable angina pectoris].
AB - In 14 patients with stable angina pectoris we examined the effect of
pentoxifyline (PTX) on oxidative metabolism of TNF-alpha-priming neutrophils. The
control group consisted of 21 patients with stable angina pectoris without
pentoxifylline administration. Blood samples for examination were taken from
basilic vein (peripheral blood) and coronary sinus immediately before PTCA
procedure. In PTX-group was found the significant decrease in spontaneous CL of
TNF-alpha-priming neutrophils from coronary sinus blood (1231.0 +/- 119.4 mV x
min), in comparison to the control group (1374 +/- 124.4 mV x min). In PTX-group
was found the significant decrease in fMLP stimulated CL of TNF-alpha-priming
neutrophils from peripheral blood (4219.0 +/- 707.2 mV x min) and coronary sinus
blood (4322.0 +/- 664.4 mV x min), in comparison to the control group (5248.0 +/-
595.8 mV x min and 4973.0 +/- 536.5 mV x min; respectively). There were no
differences between both groups in PMA stimulated CL of TNF-alpha-priming
neutrophils.
PMID- 9760818
TI - [Levels of tumor necrosis factor alpha in serum of patients with
hyperlipoproteinemia IIB before and after micronized fenofibrate therapy].
AB - Tumor necrosis factor alpha (TNF alpha) secreted by activated macrophages
stimulates proliferation and migration of vascular smooth muscle in
atherogenesis. Up to now, the effect of fibrates on concentration of TNF-alpha
has not been investigated. The aim of this study was to estimate TNF-alpha plasma
concentration in healthy subjects before and after fenofibrate therapy in
patients with hyperlipoproteinaemia IIb and to correlate their levels with plasma
concentration of total cholesterol (TC), low density lipoproteins (LDL) and
apolipoprotein B (ApoB). METHODS: 10 patients with hyperlipoproteinaemia IIb were
treated with micronized fenofibrate (Lipanthyl 200 m-Fournier) for 1 month.
Cytokines levels before and after therapy was measured by the ELISA method with
Genzyme kits. RESULTS: The levels of lipid parameters at the onset study were as
follows: TC: 265.4 +/- 9.4 mg%, TG: 344 +/- 53 mg%, LDL: 167.2 +/- 4.7 mg%, and
ApoB: 1.62 +/- 0.05 g/l. After 1-month therapy with Lipanthyl 200 m the
parameters decreased: TC 206 +/- 16 mg% (p < 0.05), TG: 194 +/- 30 mg% (p <
0.05), ApoB: 1.43 +/- 0.04 g/l (p < 0.01), and LDL: 144.4 +/- 12.9 mg% (ns). The
decreased level of TC, TG and LDL correlated with the decreased concentration of
TNF alpha. Before treatment the TNF concentration was 19.2 +/- 1.6 pg/ml and was
higher than the concentration of control subjects (9.9 +/- 1.1 pg/ml, p < 0.01).
After 1-month therapy the level of TNF alpha in blood from patient was 9.2 +/-
1.0 pg/ml (p < 0.01). The results of this study indicate that the concentrations
of TNF alpha in plasma from hyperlipidemic patients are higher than
concentrations of healthy subjects. Fenofibrate decreased the levels of this
cytokine. This effect may be of significance for the treatment of HLPIIb and of
atherosclerosis prevention.
PMID- 9760819
TI - [Levels of L-carnitine in serum of patients with chronic renal failure treated by
hemodialysis (HD)].
AB - Low serum levels of the carnitine in chronic uremic patients treated by
hemodialysis is one of the causes of muscle weakness. In 50 patients with chronic
renal failure treated by HD and in 13 nondialyzed patients EMG and measurement of
nerve conduction velocity were performed. In 25 of 50 patients treated with HD
and in 13 non-dialyzed patients serum concentration of free and total carnitine
were measured. In HD patients serum level of carnitine was significantly lower as
compared to the control group of healthy subjects and to the nondialyzed
patients. In all patients the EMG investigations showed the traits of the
neurogenic atrophy of the muscles. The correlation between the amplitude of
muscle potentials and serum levels of carnitine suggests that the depletion of
carnitine may play a role in severity uremic myopathy.
PMID- 9760820
TI - [Evaluation of the rate for reaching steady state during oral propafenone therapy
in patients with ventricular arrhythmias].
AB - We prospectively evaluated reaching of steady state and clinical efficacy of
propafenone (PPF), class Ic antiarrhythmic agent, in 16 patients (pts) (age 46
69, mean 57 years) with symptomatic ventricular arrhythmias (Low class II and
IV). The majority (13 pts) had coronary artery disease. Drug was administered for
7 days (daily dose: 3 x 150 mg). Efficacy was defined as > 80% reduction of
ventricular premature complexes (VPC) and class IV elimination in 24-hours Holter
recording. Responders were continued on PPF for 3 weeks, in non-responders dose
was titrated to 900 mg a day for the next 7 days. After second Holter evaluation
the treatment was continued for 2 weeks in responders group. The non-responders
were switched to other drug. After 4 weeks final Holter monitoring was performed.
Serum concentration of PPF and its 2 metabolites: 5-hydroxy PPF and N-depropyl
PPF were determined in 2, 3, 4, 5, 6, 7th day, just before the morning dose (3 x
150 mg/day) in 9 pts. RESULTS: Trough serum concentrations of PPF differed in
high degree: 0-226 ng/ml (2nd day), 22-438 ng/ml (4th day), 42-614 ng/ml (6-7
day). An increasing tendency of serum concentrations of PPF was observed, so
steady-state was not reached. This great dispersion of concentration values is
because of non-linear metabolism and individual differences. Defined efficacy
critetion was achieved in 62% pts, 56% for lower dose. Mean frequency of VPC was
reduced by 86% in 24-hour Holter recording and per hour (p = 0.0011). Reduction
of couplets/24 h was 87% (p = 0.0175). Significant prolongation of PQ (14%, p =
0.009) and QRS (13%, p = 0.0052) were observed. Changes of QT interval were not
significant. One case of proarrhythmia was the cause of stopping the treatment.
CONCLUSIONS: Serum concentrations' values undermine common opinion, that steady
state can be reached after 1-2 days of treatment. High dispersion of serum levels
is the result of nonlinear metabolism of PPF and individual differences. In spite
of this the study showed defined antiarrhythmic efficacy in 62.5% pts. In this
group 90% success rate was achieved after lower dose 3 x 150 mg.
PMID- 9760821
TI - [Hematological problems in patients with bronchial cancer].
AB - Four patients with lung cancer and hematological disorders occurring in different
stages of the disease are presented. In three out of them cancer metastases were
found prior to the discovery of the primary focus. In two patients those
metastases were localized in the bone marrow resulting in the hematological
picture of the myelodysplastic syndrome and osteomyelofibrosis. In one of them
acute lymphoblastic leukemia developed after short-lasting remission involving
the regression of bone marrow metastases of the cancer. In one patient lymph node
enlargement, constitutional symptoms and laboratory signs of inflammation led to
the preliminary diagnosis of Hodgkin disease. In the remaining patient acute
leukemia resistant to chemotherapy developed 34 month after the diagnosis of lung
cancer. Our observations point to the necessity of the through diagnosis in every
case of hematologic abnormalities of unknown origin and the search of a possible
underlying malignancy.
PMID- 9760822
TI - [Patent ductus arteriosus (Botall). Modern treatment patterns in children and
adults].
PMID- 9760823
TI - [Watermelon stomach--etiopathogenesis, diagnosis, differentiation and treatment].
PMID- 9760824
TI - [Aminoglycoside antibiotics--should they be administered in a single dose?
Practical point of view].
PMID- 9760825
TI - [Professor Karel Horky awarded with the honorary medal of the Polish Society of
Internal Medicine].
PMID- 9760826
TI - [Mechanisms of multidrug resistance in tumor cells and analytical methods for its
detection].
AB - We reviewed mechanisms of multidrug resistance (MDR) phenotype in tumor cells and
evaluated analytical methods for detection of clinical MDR. A well-recognized
mechanism of MDR phenotype is the induction and increased expression of P
glycoprotein (P-gp) which is a 170 kDa cellular transmembrane protein encoded by
a multidrug-resistance 1 gene (MDR1) and works as a drug efflux pump. Cellular
MDR phenotype through P-gp/MDR1 can be detectable at protein level by: (1) using
immunohistochemical method, flow cytometric assay and Western blot analysis with
monoclonal antibodies against human P-gp, and (2) measuring Rhodamine 123 dye
efflux as a functional assay of P-gp. Molecular knowledge and recent technical
progress enable to determine MDR1 gene expression by RT-PCR-based analytical
methods as well as conventional quantification methods of gene expression such as
Northern blot analysis. In the evaluation of P-gp/MDR1 expression in clinical
samples, in which amount of materials was limited, utilization of simple and
sensitive methods like competitive RT-PCR assay might be efficacious for its
quantitative detection in clinical laboratories. Evidences which showed the
positive correlation between the expression of P-gp/MDR1 and clinical resistance
or refractoriness of tumor cells to anticancer drugs involved in MDR have been
accumulated and support the clinical importance of its detection to circumvent
resistance with alternate use of non-MDR drugs.
PMID- 9760827
TI - [Age-related changes of electrocardiographic wave].
AB - Magnetocardiograms (MCGs) were recorded by means of a second-derivative SQUID
(superconducting quantum interference device) magnetometer in 150 normal subjects
(25-34 years old, 30 cases; 35-44 years old, 30 cases; 45-54 years old, 30 cases;
55-64 years old, 30 cases; 65-74 years old, 30 cases) to investigate whether
cardiac current would change with age. Based on these MCG records at 36 points on
the anterior chest wall, isomagnetic maps during QRS wave were constructed, and
dipole moments was calculated mathematically. The amplitude of RV5 and SV1 + RV5
in ECG were larger in 65-74-year-old women compared to those in women of other
ages, and SV1 + RV5 was smaller in 45-74-year-old men compared to those in 25-44
year-old men. However, dipole moments deduced from MCG did not differ with age.
These results suggest that age-related changes in the amplitude of QRS wave in
ECG do not affect the change in electromotive force with aging.
PMID- 9760828
TI - [Association of bone mineral density with vitamin D receptor gene polymorphism-
changes in radial bone mineral density with long-term follow-up: longitudinal
study].
AB - Recent studies have shown that genetic effects on bone mineral density (BMD) and
bone turnover are related to vitamin D receptor (VDR) gene polymorphism. However,
discordant studies have been published and it is still not clear whether VDR
genotypes influence bone mass accretion and/or postmenopausal bone loss. To
assess allelic influence of the VDR gene on BMD, we determined changes in 1/6
radial-BMD by several repeat measurements in the same subjects for about ten
years and analyzed VDR polymorphism of BsmI restriction enzyme in 53 normal
healthy Japanese women (age: 50.3 +/- 4.7 years, mean +/- SD). Twenty-seven (age:
53.2 +/- 4.7 years) of the subjects were post-menopausal (POST group). Among
these 53 subjects, the distribution of bb, Bb and BB genotypes was 64.2%, 34% and
1.9%, respectively. The genotype frequencies in this study were very similar to
those in previous reports concerning other Japanese women. There was no
difference between the b group (women with bb genotype) and B group (women with
BB or Bb genotype) in age, body weight, height, body mass index (BMI), years
since menopause, serum osteocalcin and serum alkaline phosphatase values. In the
POST group, BMD of the B group at menopause was lower than that of the b group (p
< 0.05). About ten years after menopause, BMD did not differ significantly
between these groups because the decrease in BMD in the b group was larger than
that in the B group. Regarding changes in BMD in the POST group for four years
after menopause, BMD of the b group was significantly decreased compared with the
B group (p < 0.01). Our findings suggest that the differences in BMD by VDR
genotype were larger among pre- and pri-menopausal women and seemed to decrease
with years after menopause. It is suggested that there are other factors
influencing BMD and postmenopausal bone loss in elderly women.
PMID- 9760829
TI - [Characterization and problems regarding clinical reference ranges of aged
subjects on clinical chemistry].
AB - Various characteristic clinical laboratory testing data related to clinical
chemistry were collected from 11 institutes across the nation, and age-related
clinical reference values, reference intervals and within-subject biological
variations were calculated. Using these calculated results, characterization of
aged-related reference ranges and the method of determining an aged subject's
testing values were investigated. From these results, the following facts became
clear. Estimation of health-associated reference intervals for aged subjects was
very difficult. As the aged subject's reference values differ remarkably by sex
and age on several test items, sex- and age-related clinical reference values are
necessary. In case of the mass screening survey which utilizes preceding healthy
values, we should decide by within-subject biological variation. We usually use
reference ranges to decide whether the measured values are located within these
ranges, and must use a differential value to speculate regarding a particular
disease. These results indicate that multiple standard must be prepared for each
clinical laboratory testing value, and that it is ideal to be able to select a
suitable standard for the subjects state. To select a suitable standard
clinically, we need an expert system. For this purpose, much more basic data
concerning reference ranges, differential values and so on must be accumulated.
PMID- 9760830
TI - [Lipid peroxide and antioxidants in the elderly].
AB - Aging is associated with changes in physical characteristics and decline of many
physiological functions. The aging process have been described by various
theories, in particular the free radical theory of aging has received widespread
attention. It has been accepted that the oxidative stress or damage induced by
free radicals is related to aging. In this study, we determined the serum
concentration of lipid peroxide and antioxidant as biomarker for aging. Healthy
subjects were classified into 3 groups, elderly (65-), middle-aged (40-64) and
young group (20-39). Findings in the elderly were as follows: 1. Lipid peroxides
in the elderly group were significantly higher than those in the young group. 2.
Preventive antioxidant concentrations of superoxide dismutase, glutathione
peroxidase and albumin were lower than those in the young group, but
ceruloplasmin values increased and catalase activity was unchanged. 3. The total
antioxidant capacity of serum was slightly decreased. 4. Superoxide generation by
neutrophils while resting was significantly higher in the young group.
PMID- 9760831
TI - [A feature of hematological findings in myelodysplastic syndromes].
AB - Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis in
one or more hematopoietic lines with abnormal morphology and peripheral blood
cytopenia. Primary MDS are more common in elderly patients and rare in children
and young adults. The diagnosis of MDS in patients with unexplained cytopenias
requires careful morphologic evaluation of both the peripheral blood and bone
marrow cells. To examine which abnormalities detected by routine examination
suggest MDS, we analyzed the hematological findings of peripheral blood in
seventy-six cases of MDS. Anemia (> 60%), leukopenia (> 40%), thrombocytopenia (>
70%) as well as blast (> 40%) were often found. The prevalence of MDS was
relatively high in patients with morphological abnormalities such as elliptocyte,
dacryocyte, erythroblast, pseudo-Pelger-Huet anomaly, decreased secondary
granules and giant platelets. Careful attention should be paid to these findings
especially elderly patients, since these may provide clues to the diagnosis of
MDS.
PMID- 9760832
TI - [Gene therapy for hematological malignancies].
PMID- 9760833
TI - [Lactate metabolism and lactic acidosis].
AB - Lactate can be viewed as a metabolic dead end in that it can only be produced or
utilized via pyruvate. Lactate production is determined primarily by pyruvate
concentration and to a lesser extend by the redox state. Increased lactate
production may result from tissue hypoxia, alkalosis, catecholamine and alanine
transamination to pyruvate. Hyperlactatemia is observed in many pathological
conditions. Current diagnostic criteria for lactic acidosis are a pH less than
7.35 and lactate concentration greater than 5 to 6 mmol/l. In our study series,
malignancy was the most common underlying disease accompanied by lactic acidosis.
Organ failure, cardiovascular disease and diabetes mellitus were also common. The
prognosis of patients with these diseases were grave. In cases of lactic acidosis
associated with diabetes mellitus, alcoholic liver disease, rhabdomyolysis and
diabetic comas were noticeable as complications. Alcohol abuse was the most
common cause of lactic acidosis associated with diabetes mellitus. In these
cases, laboratory data showed prominent hyperlactatemia, hyperglycemia and
acidemia and elevated anion gap. The mortality rate in these cases was 36% and
higher in cases with organ failure. Treatment of lactic acidosis consists of
alkalization by sodium bicarbonate with carbicarb, insulin-glucose-infusion,
dichloroacetate therapy, tham administration, bicarbonate-buffered peritoneal
dialysis and high bicarbonate-containing dialysis.
PMID- 9760835
TI - [The role of chemokines such as RANTES in allergic disease].
AB - Much attention has recently been focused on the role of allergic inflammatory
reaction in asthma. Eosinophils are considered to be the major type of
inflammatory cell involved in bronchial asthma, since eosinophil-specific granule
proteins can damage bronchial mucosal cells. Chemokines related to the beta
subfamily, the so-called platelet factor 4 (PF4) superfamily have been shown to
stimulate human eosinophils or basophils, and are considered to be important
mediators of inflammation. RANTES may be released from activated platelets and is
considered to play an important role in various immune and allergic disorders.
RANTES is a potent chemoattractant for various inflammatory cells such as
eosinophils, as well as for memory T cells and monocytes, thus potentially
recruiting these cells from the circulation to an inflamed focus. Involvement of
eosinophils and T cells in bronchial asthma has also been reported. To extend our
understanding of the participation of eosinophils, T cells, and RANTES in the
pathogenesis of allergic disease, we demonstrated the important roles of
chemokines such as RANTES in allergic disease.
PMID- 9760836
TI - [Molecular mechanism of interleukin-8 gene expression].
AB - Evidence is accumulating that interleukin-8 (IL-8), discovered as a potent
neutrophil chemotactic factor, plays a crucial role in establishing acute
neutrophil-mediated inflammation by exerting various activities against non
leukocytic as well as leukocytic cells. Various types of cells can rapidly
produce a large amount of IL-8 upon stimulation with inflammatory stimuli, such
as lipopolysaccharide, IL-1, and tumor necrosis factor (TNF). However, IL-8
production is tightly regulated at several levels, particularly at the
transcriptional levels to prevent aberrant production. Our previous experiments
demonstrated that IL-8 gene transcription requires the cooperative activation of
a transcription factor, NF-kappa B, with an additional transcription factor, AP-1
or NF-IL6, depending on types of cells and stimuli. In addition, we recently
observed that infection with Helicobacter pylori or cytomegalovirus activated NF
kappa B, therapy inducing IL-8 protein secretion as well as IL-8 gene
transcription. Moreover, IL-8, in turn, enhanced cytomegalovirus replication and
infectious virion production. Collectively, these results suggest the potential
involvement of IL-8 in the pathology of bacterial or viral infection.
PMID- 9760837
TI - [The examination of apoE phenotypes in diabetic patients with peripheral
neuropathy].
AB - Apolipoprotein E (apoE), which is reported to recognize the low density
lipoprotein receptor and remnant receptor, mediates the delivery of cholesterol
and other lipids to the cells all over the body. There are several phenotypes
such as apoE2, apoE3 and apoE4. Recently, it is reported that apoE plays an
important role in neurite outgrowth. To determine whether apoE phenotype is
concerned in diabetic peripheral neuropathy, we investigated the incidence of
apoE phenotypes in diabetic patients with peripheral neuropathy. The occurrence
of retinopathy and nephropathy were not different in apoE2, apoE3 and apoE4.
However, the frequency of diabetic neuropathy was higher in apoE4 than apoE2 and
apoE3 (p < 0.05). Furthermore, as the stage of diabetic neuropathy advanced, the
incidence of apoE4 increased. From these results we conclude that apoE phenotype
influences the progress of diabetic peripheral neuropathy and that apoE4
contributes to the deterioration of diabetic peripheral neuropathy.
PMID- 9760838
TI - [Basic evaluation for new antimicrobial susceptibility testing of Mycobacterium
tuberculosis by bioluminescence assay of mycobacterial ATP].
AB - It has been reported that the number of living bacteria is correlated to their
ATP contents. Based on this, ATP measurement was applied to the susceptibility
test for Mycobacterium tuberculosis to antimicrobial agents. ATP was extracted
from the bacterial suspension prepared from M. tuberculosis H37Rv grown on 1%
Ogawa medium and measured by bioluminescent assay. The highest relative light
units (RLU) was obtained when ATP was extracted with the reagent supplied by
Kikkoman Inc. (Chiba, Japan) at 100 degrees C for 3 minutes. The amounts of ATP
recovered was constant at 100 degrees C for 8 minutes. The ATP contents
correlated well with the number of bacteria expressed as CFU. The ATP contents of
M. tuberculosis H37Rv inoculated into the Middlebrook 7H9 broth medium containing
antituberculous agents were measured at days of 0, 3, 5 and 7. The control
culture showed the time-dependent increase in the RLU values, while cultures
supplemented with antimicrobial agents reduced their ATP contents concomitant
with the concentrations of drugs. The growth of tubercle bacilli was expressed as
RLU ratio, the ratio of RLU in the drug-containing cultures to those in drug-free
ones. RLU ratio of 0.5 or less was determined as sensitive and the ratio of more
than 0.5 as resistant to drugs. The inoculum size of bacteria did not affect the
days giving RLU ratio below 0.5 or 0.3. Within 7 days, susceptibilities to drugs
could be determined. In conclusion, this test is simple, rapid, sensitive and
highly reproducible and useful for the assessment of susceptibility.
PMID- 9760839
TI - [Protein-RNA molecular mimicry].
PMID- 9760840
TI - [A bacterial RNA that functions both as a tRNA and an mRNA].
PMID- 9760841
TI - [Early events occurring during light signal transduction in plants].
PMID- 9760842
TI - [Dynamic structural changes of the linear chromosomes of streptomyces and the
origin and evolution of chromosomes].
PMID- 9760843
TI - [Mechanism of biological methane formation structure and function of methyl
coenzyme M reductase].
PMID- 9760844
TI - [Crystal structure of lambda-exonuclease].
PMID- 9760845
TI - [Optical oxygen sensing technology using methallo-porphyrins].
PMID- 9760846
TI - [Therapeutic goals for blood pressure in the press].
PMID- 9760847
TI - [Surgeons on trial].
PMID- 9760848
TI - [Food and health--an international perspective].
PMID- 9760849
TI - [Is methadone a solution?].
PMID- 9760850
TI - [Is methadone efficient? Methadone therapy versus evidence-based medicine].
PMID- 9760851
TI - [Aerobic capacity in children and adolescents--Nordic results over the past 45
years].
AB - The aim of this study was to reveal whether today's children and adolescents have
lower aerobic capacity compared with earlier studies. Aerobic capacity may be
defined as the highest amount of oxygen a subject is able to consume per unit of
time. Peak oxygen uptake (VO2peak) is often used as a measure of aerobic capacity
in children. VO2peak in 196 healthy children and adolescents of both sexes, aged
8-16 years, was measured on a graded treadmill test. The mean results of VO2peak
(l.min-1) showed only small differences compared with previous studies in
Scandinavia. There was, however, greater dispersion in the present study when the
VO2peak-values were corrected for weight (ml.kg-1.min-1) than in the earlier
studies. When compared to other countries in Europe, Norwegian subjects achieved
higher values. The reason may be due to either genetic differences or to a higher
level of physical activity among the Norwegian subjects.
PMID- 9760852
TI - [Blood pressure measurements using three different cuff sizes].
AB - The use of blood pressure cuffs containing bladders of appropriate size for the
arm is a known prerequisite for correct blood pressure measurements. The Tricuff,
containing three inflatable bladders of varying dimensions, one of which is
automatically selected to fit the arm circumference, was compared to a standard
cuff (12 x 35 cm) in 137 persons. In persons with large arms (circumference > or
= 32 cm) measurement with the Tricuff showed on average 19.2 mm Hg lower systolic
pressure and 12.9 mm Hg lower diastolic pressure than with the standard cuff. In
persons with small arms (< 32 cm) the corresponding differences were 9.0 mm Hg
and 7.5 mm Hg. Compared to the Tricuff, the standard cuff overestimates blood
pressure in people with a large arm circumference. Overestimation may also be
caused by the rubber bladder bulging more from below the standard soft nylon cuff
than what the firmer texture of the Tricuff allows, resulting in falsely high
values even in persons with normal arm circumference.
PMID- 9760853
TI - [Invagination in children].
AB - Although rare, childhood intussusception is one of the most common causes of
small bowel obstruction in infancy. In these very young patients it can sometimes
be difficult to interpret the clinical signs and symptoms correctly. This
retrospective study comprises 79 children (median age 7.5 months; 24% girls and
76% boys) who experienced 83 episodes of intussusception. At admission the
diagnosis made by the referring physicians could be confirmed in only about one
third of the cases. A barium enema was part of the inhospital diagnostic process.
Non-operative treatment was attempted in 70 patients (89%), and barium enema
reduction was successful in 64%. Laparotomy was required in 33 (42%) of the
patients. No mortality, bowel perforation, or any other major complications were
encountered. The diagnosis of childhood intussusception seems difficult to
achieve in many cases, and the interpretation of, at times vague clinical signs
and symptoms remains a challenge for all clinicians who are involved in the care
of these very young patients.
PMID- 9760854
TI - [Cerebral amyloid angiopathy].
AB - Cerebral amyloid angiopathy affects the cerebral vasculature selectively, and
there is no systemic amyloidosis. Amyloid is deposited in small and medium-sized
vessels of the cortex and leptomeninges. Cerebral amyloid angiopathy is a common
cause of spontaneous lobar haemorrhage in elderly patients. However, cerebral
amyloid angiopathy may have atypical clinical and radiological presentations. We
report on five patients (three males and two females, aged 43-77 years) with
histologically verified cerebral amyloid angiopathy. One patient experienced an
acute headache attack and classical lobar haemorrhage. The other patients had
various neurological symptoms and signs, such as seizure, disturbed vision,
pareses, aphasia, and dementia that were initially diagnosed as cerebral
infarction or tumour. Two patients with cerebral amyloid angiopathy and
granulomatous angiitis responded to immunosuppressive treatment.
PMID- 9760855
TI - [Ataxia due to vitamin E deficiency].
AB - Few metabolic or degenerative ataxias can be treated pharmacologically. However
ataxia due to vitamin E deficiency can be treated effectively with vitamin E
supplementation if it is diagnosed early. We describe two ataxic patients with
vitamin E deficiency where this was the definite or probable cause of the ataxia.
Both polyneuropathy and cerebellar dysfunction were found. The deficiency was due
to intestinal resection in one case, whereas the exact mechanism was unknown in
the other case. In one of the patients there was a clear improvement of the
ataxia after vitamin E supplementation, but this had to be taken for about six to
12 months. In the other patient the symptom progression was halted, but only
slight improvement was observed. This patient therefore underwent leftsided
stereotaxic thalamotomy, which markedly alleviated his rightsided ataxic
symptoms. We stress the importance of testing for vitamin E (alpha-tocopherol) in
all patients with ataxia where there is no other known cause.
PMID- 9760856
TI - [Female urethral diverticulum].
AB - Female urethral diverticulum is a rare condition. The reported incidence varies
from 1.4-5%, depending on the population studied. The correct diagnosis is often
delayed because of unspecific symptoms from the patients' lower urogenital tract.
The classic triad of female urethral diverticulum is dribbling of purulent
matter, dyspareunia and dysuria. The majority of patients have a palpable mass
located on the anterior vaginal wall. The presentation and management of 11 women
with urethral diverticulum who where admitted to the Surgical Department of the
Central Hospital in Akershus during the period 1.1. 1975 to 1.4. 1996 is
reviewed. Investigations included vaginal examination, urethrocystoscopy,
urography and urethrography with a double balloon catheter. A palpable mass was
found in all 11 patients. The urethrography was positive in eight out of ten
patients. Diverticulectomy was performed on nine patients. In follow-up
interviews from three months to 21 years after treatment, one patient was found
to suffer from incontinence after surgery, two patients noticed recurrence of
some symptoms, and six patients were completely relieved of their complaints.
PMID- 9760857
TI - [What effects does methadone maintenance treatment have on the rehabilitation of
heroin addicts?].
AB - The purpose of the study was to determine the effect of methadone maintenance
treatment on heroin addicts. By searching in Medline and Cochrane Library two
randomized controlled trials were found where methadone was the main intervention
in the rehabilitation of heroin addicts. The trials were found among more than
2,350 articles on various aspects of methadone and were the only ones that met
our criteria for inclusion in the study. The two studies comprised 347
participants. Both trials showed that methadone maintenance treatment had a
positive effect on continuing participation in the treatment programme. One of
the trials also showed that the treatment lowered the rates of opioid and cocaine
use. It is alarming that only two randomized controlled trials could be found
evaluating the effect of methadone maintenance treatment on the rehabilitation of
heroin addicts. No trials demonstrating the effect of the treatment on mortality,
crime, prostitution or risk behaviour related to communicable diseases were
found.
PMID- 9760858
TI - [Prehospital treatment of heroin intoxication in Oslo in 1996].
AB - The number of heroin overdoses among drug addicts in Oslo is increasing. In 1996
overdoses counted for 1,248 (12%) of all emergency call-outs by the ambulance
service. Heroin can cause fatal respiratory insufficiency, and in 1996 a total of
104 deaths related to heroin overdoses were reported in Oslo. Heroin overdoses
are treated on site by ambulance personnel. Advanced cardiopulmonary
resuscitation was started on 18 of the 79 addicts who were found unconscious, and
11 persons were treated successfully. A total of 846 drug addicts had to be given
the antidote naloxone, and among these 678 (80%) persons were found in a coma.
Only 29 persons had to be transported to hospital. Early treatment probably
prevented both morbidity and mortality, no time being wasted transporting the
patients to hospital. Ambulance personnel treat all drug addicts with the same
respect as they do other patients. They have no police escort; they are familiar
with the addicts and their environment and they have gained their confidence.
Prehospital treatment saves on health services resources, and should, in our
experience, be carried out in collaboration with a hospital or other health
institutions for mutual and optimal benefit.
PMID- 9760859
TI - [Air quality and microbiologic contamination in operating theatres].
AB - The present study concerns the air quality and microbiological contamination in
two newly built operating theatres; one with laminar air flow (LAF) equipment for
cardio-thoracic operations, and one with conventional ventilation for urological
operations. Both theatres had an identical number of air exchanges (17/h),
identical microclimatic conditions and they employed the same cleaning
procedures. In the LAF-ventilated operating theatre bacterial contamination of
the air was effectively reduced to less than 10 colony-forming units (CFU)/m3 in
all 125 samples (1 m3 per sample) tested. In most samples, 118/125, the bacterial
count was less than 5 CFU/m3, despite the presence of ten persons. The
conventionally ventilated theatre reached values up to 120 CFU/m3 during the most
active period of the day when approximately seven persons were present. The LAF
ventilation reduced both the content of particles in the air and contamination by
bacteria on the floor. In both theatres cleaning procedures had only a low impact
on CFU in the air and on the floor. The use of diathermia markedly increased the
level of small particles in the air, and this may influence the air quality in
the operating theatres.
PMID- 9760860
TI - [Folate and health--new knowledge and new recommendation].
AB - The dietary intake of folate in Norway is not optimal with regard to minimizing
the risk of birth defects (especially neural-tube defects), and poSsibly also
cardiovascular diseases and other diseases. The National Nutrition Council has
therefore initiated a project to evaluate the status of folate in Norway and to
recommend actions for necessary improvement. A protective effect of folic acid
supplements on neural-tube defects has been found in observational studies and
clinical trials. The effects of folate on cardiovascular diseases and cancer are
less certain. The estimated average intake of folate from foods in Norway is
lower than the recommended 300 micrograms per day for adult women and men, and
remarkably lower than the 400 micrograms per day recommended for pregnant and
lactating women. Thus, with the aim of minimizing the risk for neural-tube
defects, the National Nutrition Council now recommends that all women who are
planning pregnancy or who are likely to become pregnant have an intake of at
least 400 micrograms folate per day. Because it may be difficult to achieve this
through diet alone, and because an additional risk-lowering effect of folic acid
supplementation has been shown, a folic acid supplement of 400 micrograms per day
is recommended for this group. The supplement should be taken one month before
conception and during the first two months of pregnancy. Fortification of foods
with folate is not recommended because some groups may then exceed the
recommended upper intake level.
PMID- 9760861
TI - [Intrauterine nutrition].
AB - Foetal or intrauterine nutrition is a subject of increasing interest. There are
two main reasons for this. The first one is the observation that being born small
for gestational age is associated with increased risk of cardiovascular disease
and diabetes later in life. The second one is the discovery that nutritional
factors directly influence activity of genes. If nutritional inadequacies in the
foetal period permanently alter the expression of genes, the individual's
susceptibility to perinatal complications and diseases later in life may be
altered. The main causes of intrauterine malnutrition are poor maternal diet,
placental insufficiency, and impaired foetal usage of nutrients. The consequences
of foetal malnutrition may include intrauterine growth retardation, congenital
malformation, a variety of neurological dysfunctions, susceptibility to birth
asphyxia, and diseases later in life; all of these are important determinants of
health throughout life.
PMID- 9760862
TI - [Physicians cannot... A poster on reality orientation in health care].
PMID- 9760863
TI - [We have to take the Bristol business seriously].
PMID- 9760864
TI - [A-clinics and treatment of drug addicts].
PMID- 9760865
TI - [Risk of abuse when using zopiclone].
PMID- 9760866
TI - [Recruitment to medical research].
PMID- 9760867
TI - [Do the new instructions from the EU threaten children's health?].
PMID- 9760868
TI - Physical mapping and activity of ribosomal RNA genes in mussel Mytilus
galloprovincialis.
AB - In bivalve molluscs, NOR analysis was carried out by silver staining, and
extensive intra- and interindividual differences in the apparent number of NORs
were reported. In this work, we determine the physical mapping of 18S and 28S
ribosomal genes of the mussel M. galloprovincialis by fluorescence in situ
hybridization (FISH). We also apply silver staining to the same individuals in
order to determine if structural changes are involved in the heteromorphism
detected by this technique. Our results show that rDNA loci map on the telomeric
region of the long arm of two submetacentric-subtelocentric chromosome pairs. In
addition to variations in NOR expression, we found some cases of structural
variations that affect the number of rDNA loci between individuals and the
location of the rDNA locus between the cells of the individual. We suggest that
FISH should be applied to other bivalves to assess the variation of rDNA loci and
undertake more accurate interspecific comparisons.
PMID- 9760869
TI - Geographical divergence for quantitative traits in colonising populations of
Drosophila kikkawai from India.
AB - There are significant geographical variations for four quantitative traits among
eight natural populations of Drosophila kikkawai along the Indian latitudinal
transect (8.29 to 33 degrees N). Body weight, wing length, thorax length, and
ovariole number exhibit significant clinal variation with increase in latitutde.
Genetic correlations between all the four traits are significantly higher. Slope
values for body weight and wing length are higher (2.32 per degree latitude)
while lower for thorax length (0.70) and ovariole number (0.56). South Indian
populations are characterised by lower mean values but higher variances as well
as CV values as compared with northern populations. Multiple regression analyses
(on the basis of temperature related climatic variables) evidence significantly
higher association between all the four traits and coefficient of variation of
mean annual temperature (seasonal thermal amplitude; TCV). Thus, genetic
differentiations for quantitative traits in D. kikkawai are due to selective
pressure from variable seasonal environmental conditions occurring on the
southern tropical versus northern subtropical regions of the Indian subcontinent.
PMID- 9760870
TI - Five new cases of reciprocal translocation in the domestic pig.
AB - Five new cases of reciprocal translocation in the domestic pig are described.
Three of them, rep(3;5)(p1.3;q2.3), rep(6;13)(p1.5;q4.1) and
rep(13;17)(q4.1;q1.1) were found in boars with decreased litter size. The
remaining two were identified in animals karyotyped before reproduction: a young
boar, rep(4;6)(q2.1;q2.8), and a gilt, rep(2;14)(q1.3;q2.7). A parental origin by
inheritance of the translocations was established in cases 1, 4, and 5. A
decrease in prolificacy of 43% and 34% was estimated in cases 1 and 3,
respectively.
PMID- 9760871
TI - An unusual translocation between 12tel and 14q11 in a large kindred.
AB - In one couple investigated because of recurrent abortions, the female was found
to have an unusual translocation between the long arm of the telomeric region of
chromosome 12 and the long arm of the chromosome 14 at band q11. We studied ten
additional members of the family who were under the risk of the same chromosomal
rearrangement, and four of them were found to be carriers. The diagnosis of this
translocation was determined using different banding techniques and FISH. The
karyotype was found to be 45,XX,t(12;14)(qtel;q11).
PMID- 9760872
TI - The phylogenetic position of Drosophila eskoi deduced from P element and Adh
sequence data.
AB - PCR screening with primers specific for the T-, M-, and O-type P element
subfamilies was performed to investigate the interspecific distribution in 18
species and to reconstruct the phylogenetic history of the various types within
the obscura species group. T-type elements occur in D. ambigua, D. tristis, D.
obscura, D. subsilvestris, and D. eskoi. In the genomes of D. subobscura, D.
madeirensis, and D. guanche they are present in the form of terminally truncated
T-type derivatives. The wide distribution suggests that the T-type subfamily had
a long evolutionary history in the obscura lineage. In contrast, the patchy
occurrence of M- and O-type elements can be ascribed to four independent events
of horizontal invasion of different lineages. The cladogenesis of the obscura
group was investigated using a partial sequence of the Adh gene as a marker. In
contrast to earlier findings, the position of D. eskoi had to be revised. D.
eskoi appears as the closest relative of the D. ambigua clade, whereas D.
tsukubaensis is the sister taxon of the species pair D. bifasciata/D. imaii. This
result is in good accordance with the P element data, where high sequence
similarity (95%) was found among the T-type elements of D. eskoi and those of D.
ambigua and D. tristis.
PMID- 9760873
TI - Detailed genetic and physical mapping in the Sjogren-Larsson syndrome gene region
in 17p11.2.
AB - Sjogren-Larsson syndrome (SLS) is an autosomal recessive disorder characterised
by mental retardation, spasticity, and ichthyosis. In 1994, SLS was linked to
chromosome 17 and the gene causing the disorder was recently identified as fatty
aldehyde dehydrogenase (FALDH) located in 17p11.2. In this paper we present a
detailed genetic and physical map of the region surrounding the SLS/FALDH locus,
produced by using new microsatellite markers analysed on the extensive Swedish
family material, a radiation hybrid panel, and yeast artificial chromosomes
(YACs).
PMID- 9760874
TI - Comparative karyotype of pig and cattle using whole chromosome painting probes.
AB - The extent and distribution of conserved chromosomal segments between pig and
cattle chromosomes were established using hybridization of porcine chromosome
painting probes on bovine metaphases. A total of 44 segments of conserved synteny
were identified, resulting in a nearly complete coverage of the bovine karyotype.
This study provides new data on chromosome evolution of mammals.
PMID- 9760875
TI - Microdissection of pig chromosomes: dissection of whole chromosomes, arms and
bands for construction of paints and libraries.
AB - Chromosome microdissection is an important means to efficiently generate a large
number of markers from a desired region of a genome. The present study was
designed to initiate microdissection and amplification of DNA from whole
chromosomes, arms, or bands of porcine chromosomes. The following pig (SSC)
chromosomes/segments were scraped: SSC1p, SSC1q26-q2.13, SSC2q11-q14, SSC4q12
q25, SSC13, SSC13q12-q31, SSC13q32-q43, SSC13q32-q43, SSC15, and SSC16q21-q23.
After amplification and PCR-labelling, the DNA from the dissected segments were
painted back to normal metaphase chromosomes to test their identity.
Microdissection of some of the segments (on SSC4, 13 and 15) coincides with the
mapping of economically important traits. As a first step towards generation of
markers, microcloning of amplified product from SSC1p and SSC15 was carried out.
The libraries were screened with a (GT)15 oligonucleotide probe. Future prospects
of such a work in farm animals are discussed.
PMID- 9760876
TI - Phylogenetic status of brown bears Ursus arctos of Asia: a preliminary result
inferred from mitochondrial DNA control region sequences.
PMID- 9760877
TI - Immortalized mouse odontoblast cell line MO6-G3 application for in vitro
biocompatibility testing.
AB - PURPOSE: This study was designed to determine the usefulness of an established
stable immortalized mouse odontoblast cell line (MO6-G3) for dental material
biocompatibility testing. Using a standard toxicity assay based on cell
respiratory activity, the response to MO6-G3 cells was compared to the mouse
fibroblastic cell line, L929, presently used for dental materials testing. The
dental resin monomer TEGDMA was used as the dental material for the assay.
MATERIALS AND METHODS: Cell lines (1 x 10(3)/well) were plated in 96 well culture
plates and grown in DMEM supplemented with 10% FCS, 100 units/ml each of
penicillin and streptomycin, and 50 micrograms/ml ascorbic acid in an atmosphere
of 95% air and 5% CO2. Cells were exposed to TEGDMA resin monomer covering a dose
range of 1 x 10(-6) to 0.5 x 10(-3) M. Unexposed control cells, as well as cells
exposed to the DMSO vehicle in which the TEGDMA was dissolved, were included in
all assays. Cytotoxicity was evaluated by determining cell respiratory activity
spectrophotometrically using the tetrazolium compound WST-1. RESULTS: Statistical
analysis by ANOVA using Tukey's method for pair wise comparisons as the post hoc
test indicated toxic effects of TEGDMA at 1 x 10(-5) M in the odontoblast cell
line MO6-G3. By contrast, the monomer produced no toxic effects on the L929
fibroblast cell line after 24 hours of exposure, over the entire concentration
range tested. Furthermore, MO6-G3 cells exposed to a concentration of 0.5 x 10(
3) M were unable to recover from the effects of the exposure 48 hours after
removal of the resin. MO6-G3 cells exposed to 1 x 10(-4) and 0.5 x 10(-4) TEGDMA
recovered 40-50% and 75-80% of control respiratory activity respectively, 48
hours after removal of the resin. Respiratory activity by L929 cells exposed to
all TEGDMA concentrations tested was not different from the vehicle control 48
hours after removal of the resin.
PMID- 9760878
TI - Criteria for standardizing and increasing credibility of direct pulp capping
studies.
AB - There are many skeptics who condemn pulp capping but like to keep an eye on the
research progress being made. Considerable literature emphasizes the negative
aspects of vital pulp therapy and discourages its practice. Some clinicians and
investigators continue to condemn pulp capping therapy for the same reasons
reported in the literature 80 years ago despite the advances made in pulp
biology. Clinicians are well aware of the immediate and long-term success rates
after root canal therapy, but are less certain of the success of pulp capping. A
number of nagging questions plague clinicians, when confronted with the choice of
treatment. The research data on pulp capping is at times inadequate, confusing,
misleading or even incorrect and diminishes the confidence of the practitioner in
performing pulp capping.
PMID- 9760879
TI - Early and intermediate time response of the dental pulp to an acid etch technique
in vivo.
AB - PURPOSE: To present the ultrastructural features of the pulpal responses,
following the application of All-Bond 2 to acid-conditioned, deep, unexposed
coronal dentin and exposed pulps in human teeth. MATERIALS AND METHODS:
Cylindrical Class V cavities were prepared in human premolars. In the non
exposure group an attempt was made to prepare the floor of the cavity to +/- 0.5
mm from the pulp. In the exposure group, the pulps were intentionally exposed.
After hemostasis, the preparation was etched with 10% phosphoric acid. The teeth
were restored with All-Bond 2. Histological evaluation was done at 0-7, 28-35,
and > 90 days. RESULTS: A typical connective tissue response to injury was
observed in the majority of the specimens. Irreversible injury to the
odontoblasts closest to the site of cavity preparations resulted in the death of
these cells. This was followed by an early neutrophilic response, a subsequent
macrophage response and a fibroblastic response that led to the deposition of
either reparative dentin or calcific bridge formation by odontoblast-like cells.
However, another notable feature was the consistent observation of resin
particulates within the dentin-pulp complex. These resin particulates could have
been indirectly introduced into the pulp through the pertubation of the
junctional complexes or the death of the odontoblasts. They may also enter the
pulp directly through a pulpal exposure. In some specimens, the presence of these
resin particulates appeared to have triggered a foreign body response,
characterized by the presence of a mononuclear inflammatory infiltrate as well as
the appearance of multinuclear giant cells. The persistence of unresolved chronic
inflammation was associated with the lack of calcific bridge formation in these
specimens.
PMID- 9760880
TI - The disastrous effects of the "total etch" technique in vital pulp capping in
primates.
AB - PURPOSE: To determine by means of a histopathological study in sub-human primates
whether etching of an exposed pulp (the "Total Etch" technique) followed by
capping with dentin bonding agents is a viable clinical treatment modality.
MATERIALS AND METHODS: In six sub-human primates, 147 Class V preparations were
made for five experimental and two control groups. After exposing the pulps, the
preparations were intentionally contaminated, rinsed, dried and then disinfected
with a 2% chlorhexidine solution for 60 s. In the five experimental groups, the
entire preparation including the exposed pulp was etched with a 35% phosphoric
acid gel, which was rinsed after 20 s. This was followed by a second application
of chlorhexidine. In Groups 1-3, All Bond 2, ProBond and Permagen A&B dentin
bonding agents were applied as pulp capping materials. In Group 4, a light-cured
calcium hydroxide was tested while Group 5 was treated with a chemically-cured
calcium hydroxide. Groups 6 and 7, the controls, were also contaminated, rinsed,
dried and disinfected. After the exposed pulps had been protected with a
chemically-cured calcium hydroxide (Group 6) or a light-cured calcium hydroxide
(Group 7) the preparations were etched and restored with a bonded resin
composite. The effect of the above described treatments were evaluated at 5, 25
and 75 days. After sacrifice and routine histological preparation, histological
sections were graded among other parameters for inflammatory response, bridge
formation, maintenance of vitality, presence of dentin chips and evidence of
microleakage microorganisms. RESULTS: The 2% chlorhexidine applied immediately
after exposure was an effective hemostatic agent. After subsequent etching, the
hemostatic effectiveness was greatly reduced. Exposure size for all seven groups
ranged from 0.13-1.55 mm. The average at 5, 25 and 75 days measured 0.74, 0.66
and 0.77 mm, respectively. In the five experimental groups, the 25- and 75-day
groups had a total of 68 teeth of which 24 (35%) became non-vital and 23 (33%)
teeth demonstrated bridge formation. In the three experimental groups using a
bonding agent, the 25- and 75-day groups had a total of 40 teeth of which 18
(45%) became non-vital and 10 (25%) exhibited bridge formation. In the "No Etch"
control groups, the 25- and 75-day groups had 28 teeth of which two (7%) became
non-vital and 23 (82%) exhibited bridge formation. Microorganisms were found in a
large percentage of all groups, although their numbers were few. However, they
were present in vital and non-vital teeth, in the presence and absence of bridge
formation and had no direct bearing on the success or failure of the pulp capping
procedure.
PMID- 9760881
TI - Biocompatibility of primer, adhesive and resin composite systems on non-exposed
and exposed pulps of non-human primate teeth.
AB - PURPOSE: To evaluate the histologic response of 332 non-exposed and 127 exposed
monkey pulps applying nine adhesive systems. MATERIALS AND METHODS: Class V and
Class I cavities were used in non-exposed and exposed monkey pulps at the three
ISO usage time intervals. RESULTS: There were no histologic differences in pulp
responses among the nine adhesive systems used in either Class V and/or Class I
cavities when compared to pulp responses of Ca(OH)2 controls at the ISO time
intervals. The nine adhesive systems and resin composites are non-toxic to either
non-exposed or exposed pulps, being biologically compatible to pulp tissues when
placed on mechanical pulp exposures following hemorrhage control with a 2.5%
NaOCl and per manufacturers' directions. It is imperative that clinicians
understand the biological importance of hemorrhage control as well as the
technique sensitivity of hydrophilic primers in order to optimize the efficacy of
adhesives for clinical success against microleakage of bacterial factors.
PMID- 9760882
TI - Stamp out smokeless tobacco and snuff in baseball.
PMID- 9760883
TI - Painless dentistry. Fact or fiction?
PMID- 9760884
TI - Mistakes. The nexus to growth and learning.
AB - We dread mistakes because they are considered faults. The fear of making errors
keeps us from extending ourselves professionally. We are more inclined to stay
safe within the confines of current situations because there is comfort in its
certainty. We tolerate less than ideal conditions because even if we are not
prospering, we are, at least, not failing.
PMID- 9760885
TI - A dental examination of a T-rex.
PMID- 9760886
TI - Scuba diving dental risks.
PMID- 9760887
TI - Piercing news.
PMID- 9760888
TI - Coping with conflict.
PMID- 9760889
TI - Free money for dental school.
PMID- 9760890
TI - Understanding the biology of oral cancer and chemoprevention.
PMID- 9760891
TI - Mouthguards reduce injuries.
PMID- 9760892
TI - Associateships (Part 1): Landing a job.
PMID- 9760893
TI - The Pregnancy Discrimination Act.
PMID- 9760894
TI - A season for discontent.
PMID- 9760895
TI - Peri-implant microflora of implants with cemented and screw retained
suprastructures.
AB - The aims of this study were to compare clinical and microbiological features in
the peri-implant area of implants carrying either screw retained or cemented
suprastructures, and to investigate the relationship between the peri-implant
microflora, the microbiota on the inner surface of removable suprastructures, and
the periodontal microflora within the same subject. In 15 partially edentulous
patients with ITI implants used as abutments for crown and bridge
reconstructions, microbial samples were taken i) from the deepest periodontal
pocket of each quadrant, ii) from the sulcus of the implants and iii) from the
internal surface of the screw retained suprastructures. The samples were cultured
using continuous anaerobic techniques. Five patients were found with both screw
retained (S) and cemented (C) suprastructures. In these subjects the mean total
cultivable counts were significantly higher in peri-implant samples from group C
than in samples from group S. Furthermore, peri-implant samples of group S
yielded a higher proportion of coccoid cells in the darkfield microscope and
demonstrated absence of large spirochetes. From the 15 patients, Porphyromas
gingivalis was detected in 10% of the periodontal samples and in only one peri
implant sample. Prevotella intermedia was detected in 33% of the periodontal and
in 30% of the peri-implant samples. Fusobacterium spp. had a prevalence of 58% in
the periodontal samples and was recovered from 50% of the peri-implant samples.
Actinobacillus actinomycetemcomitans was not detected in any dental or peri
implant sample. In 1 case, however, the organism was recovered from the internal
surface of the suprastructure. Linear regression analysis showed a significant
relationship between the frequency of micro-organisms in peri-implant samples of
group S and in samples from the inner surface of the suprastructure. Furthermore,
there was a significant correlation between the incidence of micro-organisms in
dental samples and i) in peri-implant samples of group S and ii) in samples from
the internal suprastructure surface. These findings indicate, that the microbial
leakage through the gap between the suprastructure and the abutment plays an
important role in the bacterial colonization of the internal part of screw
retained crowns and bridges. The study furthermore confirms the impact of the
dental microflora on the microbial colonization of implants. This factor appears
to be more important than the mode of fixation of the suprastructure.
PMID- 9760896
TI - Evaluation of postsurgical crestal bone levels adjacent to non-submerged dental
implants.
AB - In most of the studies on long-term radiographic evaluations of crestal bone
levels adjacent to dental implants, no baseline radiographs taken immediately
postsurgically had been obtained. The aim of this study was to test the
reproducibility of a simple radiographic method for linear measurements of
changes in bone levels and to evaluate changes in crestal bone levels adjacent to
non-submerged ITI implants 1 year following the surgical procedure. From 128
patients enrolled in a clinical and radiographic longitudinal study 40 patients
also had radiographs taken immediately postsurgically. They were, however, not
obtained as "identical" images. The radiographs were mounted onto slides and
projected on a screen. Mesially and distally from 57 implants triplicate linear
measurements of the distance implant shoulder to bone crest were taken, using
known dimensions of the implants as internal reference distances. The median
difference of 213 (out of 228 possible) duplicate measurements was 0.00 mm
(ranging from -1.72 mm to +1.47 mm when comparing the second to the third
reading). Some 81% of the double measurements were within +/- 0.5 mm and the
precision was 0.30 mm. In the immediate postoperative radiographs the median
mesial bone level was located at 2.07 mm (distally 2.19 mm) from the implant
shoulder. A statistically significant amount of bone loss in the first year was
observed mesially (median = -0.78 mm) and distally (-0.85 mm) (Wilcoxon matched
pairs signed rank test P < or = 0.001). No statistically significant influence of
the implant location, the implant length, type of the implant (screw; cylinder)
was observed (Kruskal-Wallis P > 0.05). The age of the patients was not
correlated significantly to the amount of bone loss observed. In conclusion,
methodological limitations existed when evaluating linear bone changes in non
identical radiographs using reference dimensions of the implants. The amount of
postsurgical bone loss estimated in other studies was confirmed when using an
immediate postoperative radiograph as a baseline.
PMID- 9760897
TI - Five-year prospective follow-up report of the Astra Tech Dental Implant System in
the treatment of edentulous mandibles.
AB - This report of the 1st 2 prospective studies using the Astra Tech Implant System
and fixed detachable bridges for rehabilitation of mandibular edentulism,
presents clinical and radiographic data at the 5-year follow-up. The original
material comprised 109 subjects, 56 of whom had been included in the original
study, using the 1st generation Astra Tech Implant. Two subjects were excluded
and the 3-year follow-up report was based on the remaining 54 subjects and 310
fixtures. After some minor changes to the fixture and the abutment, the 2nd
generation Astra Tech Implant was used in 53 subjects and 308 fixtures. In all 16
subjects were lost to follow-up and the 5-year results are based on the remaining
91 subjects with 517 fixtures in function: 5 fixtures were lost due to mobility
at abutment installation and during the 1st year, 2 fixtures were removed due to
pain, and after 4 years in situ 1 fixture failed. As no clinical or radiographic
differences were obvious in the annual registrations of the 2 studies the results
have been combined. The fixed bridges were removed at 3 and 5 years to test each
fixture and none was mobile. The cumulative fixture survival rate at 5 years was
98.7% and the bridge survival rate was 100%. Of the sites 82% were plaque free,
and 96.8% showed no signs of inflammation. Over the 5-year period after bridge
insertion, i.e. from baseline registration, there was only minor deterioration in
marginal bone levels as measured on standardized intraoral radiographs: the mean
differences in mm and standard deviations (SD) were -0.09 (0.27) in the 1st year,
-0.20 (0.40) in the 3rd year, and -0.26 (0.53) in the 5th year. According to the
stringent clinical and radiographic criteria by Albrektsson and co-workers, the
successful treatment outcome and the survival rate in 91 subject over 5 years,
indicates that the Astra Tech Dental Implant System with fixed detachable bridges
is an appropriate method for rehabilitation of mandibular edentulism.
PMID- 9760898
TI - A 2-year report on maxillary and mandibular fixed partial dentures supported by
Astra Tech dental implants. A comparison of 2 implants with different surface
textures.
AB - In 50 partially edentulous patients, 133 (48 maxillary; 85 mandibular) Astra Tech
dental implants of 2 different surface textures (machined; TiO-blasted) were
alternately installed, supporting 52 fixed partial dentures (FPDs). Before
abutment connection 2 machined implants (1 mandibular; 1 maxillary) were found to
be non-osseointegrated and were replaced. Another implant could not be restored
due to a technical complication. Two FPDs were remade because of technical
complications, both because of abutment fractures. Thus, after 2 years in
function, the cumulative survival rates were 97.7% and 95.7% for implants and
prostheses, respectively. There was no statistically significant difference in
survival rate between the 2 types of implants, 100% (TiO-blasted) vs 95.3%
(machined), P = 0.24. After 2 years in function, when both jaw and type of
implants were combined, the mean (SD) marginal bone loss was 0.24 (0.69) mm. No
statistically significant difference in bone loss was found between the 2 types
of implant after 2 years of loading, 0.04 (0.82) mm, P > 0.30.
PMID- 9760899
TI - Inter- and intraobserver variability in radiographic bone level assessment at
Branemark fixtures.
AB - The aim was to determine inter- and intraobserver variability in radiographic
bone level assessments at Branemark fixtures and to study the influence of
various factors (radiographic density; projection geometry; jaw in which the
fixtures were inserted; degree of bone loss; time after fixture loading; and
number of radiographs of each fixture) on the variability. Intraoral radiographs
from bridge connection and 1- and 3-year check-ups from 15 upper and 15 lower
jaws (172 fixtures) were assessed by 6 observers. Measurements were taken from a
reference point on the fixture to the marginal bone level, and some were repeated
by all observers after 1 months. Results showed a small interobserver variation
(0.14 mm) with the intraobserver variation (0.08 mm) as its largest component.
The radiographic density and the degree of bone loss showed the strongest
influence on the interobserver variation. The only variable with a significant
effect on the intraobserver variation was the number of radiographs of each
fixture. Calculated confidence values showed that measurement reliability can be
improved by letting one observer or preferably more make several, independent
readings, allowing for the demonstration of minor differences in bone height over
time or between implant systems.
PMID- 9760900
TI - Influence of barrier occlusiveness on guided bone augmentation. An experimental
study in the rat.
AB - The present study was designed to test perforated and non-perforated barriers for
their ability to promote augmentation of bone tissue. More specifically, 1
totally occlusive barrier and 6 barriers with perforation sizes of about 10, 25,
50, 75, 100, and 300 microns and 1 group with no barriers placed (open test
chambers) were used to test the effect of a barrier's occlusiveness on the amount
and composition of augmented tissue over time. The skull of the rat was used as
the experimental area. Prefabricated, flexible silicone frames with an inferior
flange for peripheral sealing to the bone surface and a central vertical through
hole with a diameter of 3.6 mm and a height of 2 mm were used as test chambers.
The barriers were inserted to cover the superior opening of the through hole. The
healing periods were 4, 8, and 12 weeks. All test chambers exhibited newly formed
skull bone which was augmented over time. The placement of totally occlusive
barriers resulted in the slowest rate of bone tissue augmentation but in a highly
predictable manner, i.e., there were only small individual variations. Placement
of barriers with perforations exceeding 10 microns, on the other hand, resulted
in a faster rate of bone augmentation with larger individual variations and a
totally different augmentation pattern. A pronounced augmentation of calvarial
soft tissue from the sagittal suture of the skull as well as ingrowth of
suprabony connective tissue through the barriers were also observed. After 12
weeks of healing, no differences in the amount of augmented mineralized bone
related to perforation sizes > 10 microns were found. The open test chambers also
showed bone augmentation, although most of their volume was occupied by suprabony
connective tissue.
PMID- 9760901
TI - Bone healing capacity of titanium plasma-sprayed and hydroxylapatite-coated oral
implants.
AB - The influence of surface quality, in particular surface topography and implant
material, was evaluated by inserting titanium- and hydroxylapatite plasma-sprayed
coated implants into the maxilla of 10 goats. Three types of plasma-spray
coatings were applied to tapered, screw shaped implants; titanium plasma-spray
coating (TPS), titanium plasma-spray coating with additional acid passivation
(TPSA) and a bilayered coating (TPS/HA) consisting of titanium plasma-spray
coating (TPS) and a hydroxylapatite part (HA). In addition, as-machined implants
(TiM) were used as control. A total of 40 implants were inserted according a
balanced split plot design. At the end of a 3-month healing period, it appeared
that 5 implants (2 TPS, 1 TPSA, 1 TPS/HA and 1 TiM) were lost. Histological
examination revealed a stronger bone response to TPS/HA coated implants. Even the
TPS/HA coated implants induced bone formation on the part of the implant inserted
into the sinus. No signs of delamination of the TPS coatings were visible. The HA
part of the dual coating showed signs of degradation. Histomorphometrical
analysis confirmed these findings. A significant difference in bone contact (P <
0.05) was measured between the TPS/HA coated implants and the other types of
implants. Linear regression (r = 0.27) showed no correlation between the inscrew
values at the base line and the bone contact measurements 3 months after healing.
On the basis of these results, we can conclude that the chemical composition of
the HA coating has a positive influence on the bone reaction. The influence of
roughness is less evident.
PMID- 9760902
TI - Measurements of bone and frame-work deformations induced by misfit of implant
superstructures. A pilot study in rabbits.
AB - This in vivo study used a 3-D photogrammetric technique to measure distortion of
3 unit implant frame-works and bone surrounding osseointegrated implants after
securing misfitting superstructures to the implants. Four adult loop-eared
rabbits were provided with 3 implants each in the proximal part of 1 tibia each.
After a healing period of 8 weeks, a titanium frame-work was connected with a
misfit to the central implant. Three-dimensional photographs were taken before
and after securing the central screw, which induced a calculated mean preload of
246 N. Measurements and comparisons of the topography of the frame-works and
surrounding bone before and after tightening the central screw indicated a
complex and inconsistent deformation pattern. Generally, it could be observed
that the top edge of the central cylinder showed vertical movement towards the
bone of about 150 microns, always in combination with a rotation of the entire
super-structure. The head of the central implant seemed to show a corresponding
displacement towards the frame-work of about 50 to 200 microns. Bone deformation
was found to be basically localized between the implants, where compressions of
about half a millimetre were observed. This concentration of bone deformation as
a result of misfit may be one contributing factor to initial marginal bone loss,
occasionally observed after insertion of implant supported prostheses.
PMID- 9760903
TI - Antibiotic abuse: let's stop it now.
PMID- 9760904
TI - Practice management companies: illegally practicing dentistry?
PMID- 9760905
TI - Latex allergy: everyone's concern.
PMID- 9760906
TI - I-9 forms must be completed for all employees.
PMID- 9760907
TI - To buy or to lease?
PMID- 9760908
TI - Meet Dr. Michael Jennings new MDA President.
PMID- 9760909
TI - Has the dental profession become a dental industry?
PMID- 9760910
TI - Planning ahead for a secure, successful future.
PMID- 9760911
TI - Restorative considerations: comprehensive management of the embrasure space.
PMID- 9760912
TI - The physiologic restorative dimension.
PMID- 9760913
TI - How well do you know your patients?
PMID- 9760914
TI - Ethical dilemma. What would you do?
PMID- 9760915
TI - Ethical dilemma. What would you do?
PMID- 9760916
TI - Has competence replaced excellence?
PMID- 9760917
TI - Buonocore Memorial Lecture. Materials of the future: preservative or restorative?
PMID- 9760918
TI - Repairability of three resin-modified glass-ionomer restorative materials.
AB - The purpose of this study was to evaluate the repair shear bond strengths of
three resin-modified glass-ionomer restorative materials repaired at two
different times. Thirty specimens of Fuji II LC, Vitremer, and Photac-Fil were
prepared in cavities (2 mm x 7 mm) cut into acrylic resin cylinders. After the
initial fill, half of the specimens were repaired 5 minutes later and half 1 week
later. The specimens were stored in 37 degrees C distilled water when not being
repaired or tested. Repairs were made without any surface preparation of the
initial fill. Each specimen was mixed according to the manufacturer's directions,
placed in the preparation in 1-mm increments and photocured for 40 seconds. The
last increment was covered with a plastic strip and a glass slide before curing
to create a smooth surface. Repairs were accomplished by drying the specimen for
10 seconds, then adding the new material to the unprepared surface using a 3-mm
thick polytetrafluoroethylene mold. The specimens were thermocycled 500 times,
stored in 37 degrees C distilled water for 1 week, then loaded to failure in
shear at a rate of 0.5 mm/min. Data were analyzed using a one-way ANOVA and Z
value multiple comparison test to determine significant differences at the 0.05
significance level. Vitremer showed no significant difference in shear bond
strength for 5-minute and 1-week repair periods, while Fuji II LC and Photac-Fil
did. Repair bond strength of Vitremer was significantly greater than Fuji II LC
and Photac-Fil at both repair times. This study showed that time of repair
significantly affected the bond strength of two of the materials tested.
PMID- 9760919
TI - Repair of new-generation tooth-colored restoratives: methods of surface
conditioning to achieve bonding.
AB - The shear bond strength of repaired resin-modified glass-ionomer cements and
polyacid-modified composite resins after different methods of surface
conditioning was studied. For the resin-modified glass-ionomer cement, none of
the surface treatment methods had a significantly higher repair bond strength
than the control. For the polyacid-modified composite, the application of low
viscosity resin after treatment with maleic acid, polyacrylic acid, and air
abrasion appeared to be of paramount importance, for it enhanced bonding of the
repaired specimens.
PMID- 9760920
TI - Factors affecting light transmission of single-use, plastic light-curing tips.
AB - Recently, manufacturers introduced presterilized, single-use, plastic light
curing tips to be used either routinely or on patients with known or questionable
communicable health concerns. The purpose of this study was to examine the effect
of these single-use tips on light transmission compared to conventional fiber
optic bundles in a variety of commercial light-curing units. Also, the effects of
surface contact with the plastic tips (human tissues, reflective or opaque media,
and barrier films) were evaluated. Where applicable, single-use tips from two
sources (Caulk/Dentsply and Demetron) were placed in commercial curing units
(Optilux 150 and 500, MAX 100, Spectrum Curing Light, and 3M XL-3000), and the
intensity was compared to that of the conventional glass curing tip used with
that specific curing unit. Intensity readings were also made for 6 continuous
minutes using plastic tips in a high-intensity curing unit to simulate veneer
bonding. If the sides of the plastic tip came in contact with the operator's
fingers or the patient's tongue and/or cheek during a clinical procedure, a
lowering of transmitted light intensity resulted. The glow emitted from the sides
of the tip when in use may be annoying to the operator. To prevent this glare,
the operator may be tempted to treat the sides of the tip by painting, applying a
thin polymer barrier, abrasion, or wrapping in an opaque reflective material
(aluminum foil). A significant decrease in light intensity can result if plastic
curing tips contact oral tissues or bare hands. Application of thin polymer
barriers was found to significantly reduce light transmission value. Also,
surface modification (coating with paint or surface scratches) was found to
greatly reduce light intensity levels, while wrapping the tip in aluminum foil
produced a very small increase. Results indicated that transmitted light
intensity with use of plastic tips was dependent upon both the brand of plastic
tip tested and the different photocuring units. Either a slight increase or a
slight decrease in intensity was noted. Plastic tips did not degrade in
transmitted intensity when exposed to the heat produced during a simulated
veneering scenario. In summary, use of plastic, single-use light-curing tips can
provide adequate intensity for photoactivated restorative techniques; however,
the clinician must be aware of specific, clinically relevant limitations with
their use. Clinicians must also note that these tips are not designed for re-use.
PMID- 9760921
TI - Resin-infiltrated dentin layer formation of new bonding systems.
AB - The purpose of this study was to evaluate the resin-dentin interfacial morphology
and shear bond strength of several new and experimental dentin bonding systems
classified as single-bottle/total etch, multi-step/total etch, and self-etching.
Class 1 and 5 cavities were prepared from freshly extracted permanent molars and
restored with composite resin. Each bonded sample was cross sectioned and one
half was completely demineralized and deproteinized, while the other half was
polished along the cut surface to permit measurement of the thickness of resin
infiltrated dentin layer (RIDL) within intertubular dentin (iRIDL) and around the
peritubular walls (pRIDL) of resin tags by SEM. Shear bond strength was measured
for all the systems 2 minutes after photocuring. SEM showed iRIDL and resin tags
of different morphology depending on material and dentin location. The iRIDL was
thinner in superficial dentin and thicker in deep dentin. Peritubular RIDL
(pRIDL) was thinner than intertubular RIDL. Bond strength measurements varied
from 12 to 21 MPa, depending on the materials used. Self-etching primer systems
exhibited the highest bond strength, although one of the one-step/total etch
systems also yielded very high values. The contribution of pRIDL to adhesion onto
superficial dentin is limited by the small number of tubules. Single-component
bonding agents produced SEM morphology and bond strengths similar to those of
multi-step systems. Self-etching systems, despite their limited RIDL thickness,
produced the highest immediate bond strengths. Bond strength did not correlate
well with the thickness and morphology of RIDL.
PMID- 9760922
TI - Bonding of amalgam and a gallium alloy to bovine dentin.
AB - The shear bond strengths of an amalgam (Permite C) and a gallium alloy (Galloy)
to dentin, mediated by four dentin adhesives (Super-Bond D-Liner, Super-Bond D
Liner II, Paama 2, and Panavia 21), were investigated. Flat labial dentin
surfaces were prepared from bovine lower incisor teeth. A 3 mm-in-diameter area
of dentin was bonded according to each manufacturer's directions before placement
of Permite C or Galloy. The bonds were stressed in shear at a crosshead speed of
1 mm/min. The mean shear bond strengths were analyzed using one-way ANOVA and
Student's t-test, and fracture modes were assessed under X20 magnification and
analyzed using Kruskal-Wallis and Mann-Whitney U tests. Scanning electron
micrographs were taken of the bond interface of separate samples. The results
showed no significant difference among the bond strengths of Super-Bond D-Liner
(2.79 MPa, 2.69 MPa), Super-Bond D-Liner II (3.41 MPa, 2.65 MPa), and Paama 2
(0.70 MPa, 0.50 MPa) bonded to Permite C and Galloy (respective values in
parentheses); however, Panavia gave a significantly better bond with Permite C
(0.42 MPa) than with Galloy (0 MPa). Super-Bond D-Liner and Super-Bond D-Liner II
gave stronger bonds than Paama 2 and Panavia with both Permite C and Galloy. For
each dentin adhesive, there was no difference in fracture mode between Permite C
and Galloy. It was concluded that, since all bond strengths were very low, none
of the dentin adhesives tested would enhance the clinical retention of Permite C
or Galloy. However, although the use of Paama 2 with Galloy was originally
recommended by the manufacturer for dentin sealing purposes, no adhesion was
claimed.
PMID- 9760924
TI - Dental implantology through the millennium: a personal perspective and
commentary.
PMID- 9760923
TI - Intraoral repair of the fractured porcelain restoration.
AB - Until recently, there was no predictable technique for repairing the fractured
porcelain restoration. However, with the advent of many new products related to
bonding porcelain, there are techniques available today to repair fractured
porcelain with moderate expectations of success.
PMID- 9760925
TI - The implant quality scale: a clinical assessment of the health--disease
continuum.
AB - Implant success is as difficult to describe as the success criteria required for
a tooth. A range from health to disease exists in both conditions. The primary
criteria for assessing implant quality are pain and mobility. The presence of
either one greatly compromises the implant, and removal is usually indicated.
Probing depths may be related to the presence of local disease or pre-existing
tissue thickness before the implant was inserted. An increasing probing depth is
more diagnostic and signifies bone loss, gingival hyperplasia or hypertrophy.
Bone loss is usually evaluated best with probing rather than with radiographs.
The most common cause of bone loss during the first few years of function are
exaggerated factors of stress. The bleeding index is easily observed and
indicates inflammation of the gingiva. However, implant health status is not as
related to sulcular inflammation as would be the case for a natural tooth.
Implant failure is easier to describe and may consist of a variety of factors.
Any pain, vertical mobility, uncontrolled progressive bone loss, and/or
generalized periradiolucency warrant implant removal. Implant quality factors
were established by James and modified by Misch into an implant quality scale
which not only assesses the implant health-disease continuum, but relates
treatment and prognosis to the existing conditions.
PMID- 9760926
TI - The management of acrylic occlusal appliances in implant dentistry.
PMID- 9760927
TI - Autogenous bone grafts.
PMID- 9760928
TI - Simplicity is always best.
PMID- 9760929
TI - PST, the essential surgical template.
AB - The anticipated prosthesis now dictates the placement and angulation of the
implant, thereby improving the function and the aesthetics of the final result.
To establish a logical continuity between the surgical phases and the planned
prosthesis, it is essential to use a transfer device. The restorative clinician
can request a precise position and orientation of each implant with this
communication tool. However, it is difficult to use a conventional surgical
template following the soft tissue reflection and during preparation of implant
osteotomy. The proper positioning of each implant is difficult to achieve,
especially on a completely edentulous maxilla where restorations require even
more ideal implant placement.
PMID- 9760930
TI - The lessons of implant dentistry.
PMID- 9760931
TI - The Endopore implant-enhanced osseointegration with a sintered porous-surfaced
design.
AB - The Endopore implant provides a novel method for reliable fixation of endosseous
dental implants within the bone. Through the use of a porous-surfaced zone formed
by sintering Ti alloy particles of the appropriate size and under appropriate
processing conditions to a sold Ti alloy core of desired shape (tapered truncated
cone), an implant is now available that can be placed using a relatively simple
surgical procedure using either surgical burs or hand osteotomes. Of even greater
value is the suitability of this implant design for treatment of cases that
because of minimal bone height cannot be treated routinely using other currently
available implants. The high success rates experienced with significantly shorter
implant lengths compared with other designs indicate the appropriateness of this
system for difficult-to-treat cases. The Endopore system represents the next
generation of endosseous dental implants characterized by uncomplicated and
reliable treatment for a wider range of dentally-compromised patients. Its
history is founded on extensive and fully-documented research at the human
preclinical stage as well as human use experiences. The results during the past
nine years have confirmed the high expectations that those early studies
suggested.
PMID- 9760932
TI - Dental mutilation in southern African history and prehistory with special
reference to the "Cape Flats Smile".
AB - Southern Africa has a long history of dental mutilation in the form of dental
chipping and of intentional removal of anterior teeth. The first evidence is
found in the skeletons of Early Iron Age populations (ca. 1500 years before
present), but the incidence decreases in archaeological sites of more recent
origin. In modern times, dental mutilation appears to have been limited to the
people of the countries further north in Africa, but the one exception is the
presence of deliberate incisor removal amongst the communities of the Western
Cape. It is hypothesised in this paper that the modern practice in the Cape is
associated with youthful gangs in the poorer communities, and acts as part of a
rite of passage into adulthood. The "socio-sexual" theory, as reflected in such
names as the "passion gap", is shown to be both wrong and insulting. The name
"Cape Flats Smile" is recommended as a more appropriate and respectful term for
the phenomenon.
PMID- 9760933
TI - The treatment need of a group of senior dental students as assessed by the IOTN
and PAR indices.
AB - Recently the Index of Orthodontic Treatment Need (IOTN) and Peer Assessment
Rating (PAR) were introduced in the United Kingdom as a standard for future
epidemiological research in orthodontics. The purpose of this study was to assess
the suitability of these indices for South African epidemiological studies and to
evaluate the treatment need of a group of senior dental students. Examinations in
accordance with the IOTN and PAR were performed on 206 dental students by three
postgraduate orthodontic students. According to the Dental Health Component of
the IOTN 54.9 per cent of the sample had no treatment need, 26.7 per cent had a
moderate treatment need and 18.4 per cent had an urgent treatment need. 74.2 per
cent of the students were at the no-treatment-needed end of the aesthetic scale,
which compared poorly with the 88.5 per cent recorded by student self assessment.
The majority of dental students in this study were not in need of orthodontic
treatment. Certain occlusal traits common to negroids, such as bimaxillary
protrusion, are not represented in these assessment instruments and minor
adjustments may be needed to make the systems more applicable in these population
groups.
PMID- 9760934
TI - The Leaning Tower of Pisa syndrome.
PMID- 9760935
TI - New materials and techniques for endodontic-restorative treatment of a severely
damaged and compromised molar in one visit: a case report.
PMID- 9760936
TI - Guidelines for a code of ethics for dental publications. Federation Dentaire
Internationale World Dental Federation.
PMID- 9760937
TI - The International Association of Oral Pathologists ... where oral medicine and
oral pathology meet.
PMID- 9760938
TI - A successful combination of conflicting approaches to diastema closure--a case
report.
AB - The closure of anterior maxillary diastemas can be accomplished in several ways.
A case is reported where treatment initially consisted of the provision of
porcelain laminate veneer restorations, with an unsatisfactory result.
Subsequently, the restorations were reduced drastically in width and reshaped.
The tooth widths were calculated from tables of mean measurements. The spaces
were closed by orthodontic treatment and the original restorations were retained,
saving the patient considerable treatment.
PMID- 9760939
TI - Ocular complications of dental local anaesthesia.
PMID- 9760940
TI - Combination treatment of severe fluorosis.
PMID- 9760941
TI - A new device for the removal of crowns and bridges.
PMID- 9760942
TI - Optimal isolation for cementation with adhesive resin cement.
PMID- 9760943
TI - Lipoma of the floor of the mouth: report of an unusually large lesion.
AB - Although lipomas are common, benign tumours found in any part of the body, their
occurrence in the oral cavity is relatively rare. An unusual case of a large
lipoma appearing on the floor of the mouth in a 77-year-old male, is presented in
this paper. The unusual appearance in this case suggests that this tumour should
be included as a rare possibility in the differential diagnosis of swellings in
the floor of the mouth.
PMID- 9760945
TI - Guidelines for Peer Review. South African Dental Association.
PMID- 9760944
TI - Pre-floss that prosthesis.
PMID- 9760946
TI - Dental research scientist serving in two countries.
PMID- 9760947
TI - Funding college education for children.
PMID- 9760949
TI - Influenza vaccine, 1998-1999.
PMID- 9760948
TI - Two new antiplatelet drugs for angioplasty and acute coronary syndromes.
PMID- 9760950
TI - Gliadel wafers for treatment of brain tumors.
PMID- 9760951
TI - Lipid-modifying drugs.
PMID- 9760952
TI - Management of patients with unstable angina in a general cardiology unit.
AB - AIMS: To review the clinical management of patients with unstable angina and to
relate prospectively initial risk stratification, according to the Braunwald
criteria, to subsequent cardiovascular events. METHODS: From February to April
1996 we performed a three month prospective review of all patients with a
diagnosis of unstable angina admitted to the coronary care unit at Auckland
Hospital. RESULTS: One hundred and four patients (61% male), with a mean age of
64 years, were classified as high (58%), intermediate (41%) or low risk (1%) for
an adverse cardiac event. Twelve (12%) patients had a documented myocardial
infarction, of whom 11 were in the high-risk group (p = 0.038). During
hospitalisation there was one death. Twelve (12%) patients underwent inpatient
exercise testing, five of whom proceeded to a coronary angiogram prior to
hospital discharge. Twenty-two (21%) unstable patients underwent inpatient
angiography without prior exercise testing. Twenty-one (20%) patients required
revascularisation on the same admission: percutaneous coronary angioplasty (n =
14) or coronary artery bypass grafting (n = 7). Twelve of these 21 patients were
in the high-risk group (p = 0.999, NS). CONCLUSION: Patients admitted with
unstable angina had low inpatient mortality but a 12% rate of subsequent
myocardial infarction. Braunwald low-risk unstable angina patients were not
admitted to the coronary care unit. Braunwald high-risk patients were more likely
to develop a subsequent myocardial infarction. Stratification of patients into
intermediate or high-risk groups did not relate to initial medical management or
subsequent revascularisation. Thus, while this method of risk stratification may
predict cardiovascular events, it may be of limited clinical use in the New
Zealand environment.
PMID- 9760953
TI - The impact of reference pricing on clinical lipid control.
AB - AIM: Reference pricing has recently been introduced into New Zealand in an
attempt to curb rising pharmaceutical costs. Although budget savings may be
significant, the resulting alteration of established drug prescriptions has the
potential to cause harm. We undertook to assess the impact of these changes in
patients switching from simvastatin to fluvastatin following the introduction of
reference-based pricing in New Zealand. METHODS: The fasting lipid profiles of
262 patients in a defined geographic region were obtained after at least six
weeks of fluvastatin therapy. These were compared to mean lipid levels obtained
from laboratory databases for the patients while previously receiving
simvastatin. RESULTS: There was a significant increase in total cholesterol, LDL
cholesterol and triglyceride levels (p < 0.01). The elevation was less pronounced
where higher incremental doses of fluvastatin were used, although still
significant for LDL cholesterol and total cholesterol (p < 0.01). Those receiving
maximal therapy with fluvastatin experienced similar elevations in lipid as did
those on lower doses. CONCLUSION: The lipid elevations seen in this audit relate
both to the lesser potency of fluvastatin and underdosing. In this high risk
population, significant lipid elevations may conceivably produce an excess of
vascular events. The responsibility to the taxpayer should be weighed carefully
against the ethical responsibility to the individual patient and the potential to
do harm. Subtherapeutic treatment may prove more costly than all the savings from
reference pricing.
PMID- 9760954
TI - Non-insulin-dependent diabetes mellitus in New Zealand Maori: a relationship with
Class I but not Class II histocompatibility locus antigens.
AB - AIMS: To investigate the possibility of a relationship between the major
histocompatibility complex (MHC) and non-insulin-dependent diabetes mellitus
(NIDDM) in Maori. Such relationships have previously been shown in non-European
races with a high incidence of NIDDM. METHODS: We performed serological Class I
and PCR-SSP Class II HLA typing on 44 Maori with NIDDM and renal failure and
compared the results with normal Maori. RESULTS: A strong relationship with the
HLA-B40 groups of antigens (relative risk 5.1 chi 2 = 16.8, p < 0.001) was found;
this was mainly attributable to HLA-B48 and HLA-B60. There was no HLA Class II
relationship. CONCLUSION: The relationship with HLA-B40 antigens suggests that
the MHC or other genes on chromosome 6 play a role in NIDDM in Maori.
PMID- 9760955
TI - Practising dermatology via telemedicine.
AB - AIM: An interactive telemedicine service has been established between Taumarunui
Hospital and the Department of Dermatology at Waikato Hospital. The first one
hundred dermatological consultations were reviewed to see if the consultations
were satisfactory for medical staff and patients. METHODS: A proprietary video
conferencing system communicating via the Integrated Systems Digital Network was
used to conduct dermatological consultations. Data were collected regarding
waiting time, diagnosis and follow-up arrangements. Each patient was asked to
complete a questionnaire after the consultation. RESULTS: Of these consultations,
83 were newly referred patients and the rest were follow-ups. The median waiting
time for a new patient was 63 days. A variety of skin lesions (in 40 patients),
inflammatory eruptions (31) and infections (13) were diagnosed and managed.
Sixteen patients had to be seen at the base hospital for surgical treatment (7),
face-to-face diagnosis (3), patch testing (3), a second opinion (2), or for
personal reasons (1). The others were followed up locally. Savings in time and
cost to patients were noted particularly. CONCLUSION: Only about 20% of
consultations with new patients resulted in a further face-to-face appointment.
The majority of patients found the telelink acceptable. The data supported the
continuation and possible expansion of the dermatology telemedicine service.
However, improved image quality is desirable.
PMID- 9760956
TI - MMR immunisation coverage in Christchurch. Christchurch Immunisation Coordination
Committee.
AB - AIM: To measure measles-mumps-rubella (MMR) immunisation status of a birth cohort
at 18 months of age. METHOD: All children born in Christchurch in June, July and
August 1995 who were alive at 18 months of age (n = 999), were matched with MMR
immunisation benefit claims. Those not listed were traced. RESULT: The final
immunisation coverage rate was estimated at 85%. CONCLUSION: An 85% coverage rate
at 18 months fell well short of the Immunisation 2000 target of 95% coverage by
two years of age.
PMID- 9760957
TI - Is confidence in immunisation declining?
AB - There is no regular immunisation coverage information in New Zealand that is
reliable. Immunisation benefit data do provide an indication of trends. The
benefit data show a decline in coverage in 1997, after several years of improving
coverage. The reasons for the decline are not known, but media reports which
dented public and professional confidence in immunisation may have played a role.
PMID- 9760958
TI - General practitioner funding policy: from where to whither?
AB - Six public policy objectives relating to general practitioner (GP) funding since
1938 have been identified. They concern national health insurance, rural GP
shortages, care for the poor, health promotion, cost effectiveness and community
control. Each of these objectives is examined in turn, focusing on the extent to
which each has been met. In all cases past policies have been, at best, only
partially successful in meeting their objectives and have required little in the
way of dismantling prior to the introduction of new GP funding initiatives
subsequent to 1993. Theoretical principles relating to the development of
efficient and coherent public policy are discussed. New Zealand policy relating
to funding of GP services has rarely conformed to such principles. There is an
emerging consensus between social democrats and libertarians that targeted
programmes for the poor is the equitable and efficient way to proceed. A key
policy decision concerns the balance between planned primary care services for
low income groups and more traditional market style arrangements for others.
PMID- 9760959
TI - Unshackling the hospitals.
PMID- 9760961
TI - B. Ramamurthi.
PMID- 9760962
TI - Complete recovery from hemiplegia following excision of a giant basal ganglia
arteriovenous malformation.
AB - A young female harbored a large arteriovenous malformation (AVM) in the basal
ganglia associated with marked arteriovenous shunting. The complete recovery of
her neurological deficit subsequent to excision of the AVM illustrates the
reversibility of such severe cerebral impairment. Large lesions in the basal
ganglia often have been deemed inoperable. However, modern advances in
microsurgical techniques have provided the necessary illumination, magnification,
and instrumentation that was needed for the exposure and gentle resection of the
lesion in our patient.
PMID- 9760963
TI - A stereotactic approach to deep-seated central nervous system neoplasms using the
carbon dioxide laser.
AB - This report describes a technique in which deep-seated CNS neoplasms, the volume
and shape of which had been determined and stereotactically localized by computer
reconstruction of CT data, were vaporized with a carbon dioxide laser attached to
a stereotactic frame. The clinical results with 6 patients treated by this
technique are presented.
PMID- 9760964
TI - Treatment of brain tumors.
PMID- 9760965
TI - Wallenberg's syndrome caused by direct brainstem injury.
AB - A unique case of a shotgun wound producing a lateral medullary syndrome is
reported. Evidence indicating direct brainstem injury and not vascular injury is
presented. The long-term complications of this type of injury are stressed.
PMID- 9760966
TI - Traumatic transient Kluver-Bucy syndrome.
AB - A case of transient Kluver-Bucy syndrome after a gunshot wound through the head
is presented. We have found no other case of posttraumatic Kluver-Bucy syndrome
described in the literature. The original criteria for the syndrome are reviewed
and compared with findings in previously reported human cases.
PMID- 9760967
TI - What happened?
PMID- 9760968
TI - A comparison of results from center-median and basal thalamotomies for pain.
AB - In a personal series of 43 patients with chronic pain treated by thalamotomy, 23
patients had basal thalamotomy and 19 had center-median thalamotomy. Forty-nine
procedures were performed. The best results occurred in patients with pain in the
upper part of the body and in patients who had bilateral center-median
thalamotomy. Bilateral center-median thalamotomy was superior to basal
thalamotomy and had fewer side effects. Despite adverse reports, thalamotomy
remains a useful analgesic procedure.
PMID- 9760969
TI - Transseptal approach to the sella.
PMID- 9760970
TI - Tethered spinal cord in association with diastematomyelia.
AB - There is no good evidence that division of the filum terminale with simultaneous
removal of the central spur in patients with diastematomyelia improves their
eventual neurological status. We describe 5 patients in whom the filum was not
divided and who were later reported upon because of lack of improvement or
because of increasing neurological deficit. In 3 patients the division of a
congenitally short filum terminale resulted in no improvement; in the other 2,
symptoms were relieved following the division of adhesions at the site of
previous surgery.
PMID- 9760971
TI - Aggressive osteoblastoma associated with subgaleal hematoma.
AB - A 26-year-old man with a chronic subgaleal hematoma containing calcific elements
subsequently developed an aggressive osteoblastoma within the lesion. It is
presumed that the osseous elements associated with the chronic process underwent
neoplastic alteration. Such a lesion should be suspected in an individual with a
long-standing subgaleal hematoma who reports changes occurring with respect to
either size of the lesion or the development of tenderness.
PMID- 9760972
TI - A fast, simple, and satisfactory method of cranioplasty.
AB - A cranioplastic technique is described that is easy to do by making a series of
molds and an acrylic prosthesis identical to the bone segment.
PMID- 9760973
TI - An opportunity.
PMID- 9760974
TI - Symptomatic leptomeningeal metastases preceding other manifestations of occult
primary brain tumors.
AB - Rarely, primary brain tumors may present with signs and symptoms due to diffuse
multifocal leptomeningeal spread of tumor. These false localizing signs divert
attention from the primary tumor, which remains relatively silent. The two
patients reported here exemplify the confusing clinical pictures that may result.
PMID- 9760975
TI - Aneurysms of the proximal anterior cerebral artery.
PMID- 9760976
TI - An unusual case of penetrating head injury with excellent recovery.
AB - We report the remarkable case of the passage of a heavy metal rod through the
head of a 42-year-old man. The patient had an excellent outcome because of prompt
and efficient rescue efforts combined with transport to a major neurosurgical
trauma center. Reference is made to a somewhat similar case publicized over 130
years ago.
PMID- 9760977
TI - Intracranial epidermoid mimicking meningioma.
AB - A case of an epidermoid cyst in the frontal base which showed homogeneous high
density in noncontrast computed tomography, simulating a meningioma with
calcification, is reported. Operative findings and histological examination
suggested that this high density was caused by spontaneous hemorrhage into the
cyst.
PMID- 9760978
TI - Dermoid tumor.
PMID- 9760979
TI - The diagnosis of sacral lesions.
AB - Clinical courses are reviewed in 4 recent patients with sacral lesions, each of
whom was believed on initial clinical evaluation to have symptomatic herniations
of intervertebral discs. In each patient pain in the back tended to overshadow
radicular symptoms, and sphincteric disturbances were not prominent. Each patient
presented some related objective abnormality on general or neurologic
examination. The sacral lesion was invariably visible on technically satisfactory
plain roentgenograms of the spine and was obvious on sacral tomography.
Conventional myelography was useful in defining communication between the lesion
and the subarachnoid space, but otherwise typically it was only subtly and
nonspecifically abnormal. Computerized tomography (CT) proved to be the most
revealing radiographic technique, demonstrating bony detail as well as internal
structure and extent of the lesion; in conjunction with metrizamide myelography,
CT provided the most definitive anatomical study. The limited utility of
angiography in diagnosing these lesions is discussed, as are the respective
hazards of and indications for needle biopsy and open surgical exploration.
PMID- 9760980
TI - Amelanotic melanoma of the lung and brain with fenestrated intrinsic tumor
capillaries.
AB - Tissue from an amelanotic melanoma which involved the lung and brain was studied
by electron microscopy. Endothelial fenestrae were found in the intrinsic tumor
capillaries at both locations, a finding which does not appear to have been
previously reported for amelanotic melanoma. Pitfalls in the diagnosis of this
rare tumor are discussed.
PMID- 9760981
TI - Preoperative neurological status in predicting surgical outcome of spinal
epidural hematomas.
AB - The postoperative progress of 3 patients with spinal epidural hemorrhage, but
without spinal fracture or dislocation, is presented. From the literature, 158
cases were collected of spontaneous spinal epidural hematoma treated surgically.
Postoperative return of motor function was noted in 95.3%, 87%, and 45.3% of the
patients with incomplete sensorimotor, incomplete sensory but complete motor, and
complete sensorimotor lesions, respectively. Complete sensorimotor recovery
occurred in 41.9%, 26.1%, and 11.3% of these 3 groups of patients, respectively.
Recovery following surgical treatment depends on the severity of neurological
deficits before treatment. However, the absence of motor or sensorimotor
functions preoperatively does not necessarily indicate a poor prognosis.
PMID- 9760982
TI - Rathke's cleft cyst.
AB - Two cases of Rathke's cleft cyst which produced symptoms of compression of the
optic chiasm are described. The first case has been followed for five years since
the operation. No evidence of recurrence has been noticed. The prognosis after a
partial removal of the cyst wall seems to be good with this lesion. In the second
case, there was clinical and laboratory evidence of hypopituitarism and the CT
scan revealed suggestive findings to differentiate the cyst from a pituitary
adenoma.
PMID- 9760983
TI - Spinal Cord Injury Service in the VA.
PMID- 9760984
TI - Introduction: the ribonuclease A superfamily.
AB - In this multi-author issue several aspects of the ribonuclease A superfamily are
reviewed. This superfamily can be subdivided in a number of mammalian and other
vertebrate ribonuclease families. In the introduction chapter the titles of the
other contributions are presented. There is little uniformity in the nomenclature
of ribonucleases, caused in part by gene duplications, which have occurred
independently in several mammalian lineages, and which are nice examples for
explaining orthology and paralogy in molecular evolution.
PMID- 9760985
TI - The contribution of noncatalytic phosphate-binding subsites to the mechanism of
bovine pancreatic ribonuclease A.
AB - The enzymatic catalysis of polymeric substrates such as proteins, polysaccharides
or nucleic acids requires precise alignment between the enzyme and the substrate
regions flanking the region occupying the active site. In the case of
ribonucleases, enzyme-substrate binding may be directed by electrostatic
interactions between the phosphate groups of the RNA molecule and basic amino
acid residues on the enzyme. Specific interactions between the nitrogenated bases
and particular amino acids in the active site or adjacent positions may also take
place. The substrate-binding subsites of ribonuclease A have been characterized
by structural and kinetic studies. In addition to the active site (p1), the role
of other noncatalytic phosphate-binding subsites in the correct alignment of the
polymeric substrate has been proposed. p2 and p0 have been described as phosphate
binding subsites that bind the phosphate group adjacent to the 3' side and 5'
side, respectively, of the phosphate in the active site. In both cases, basic
amino acids (Lys-7 and Arg-10 in p2, and Lys-66 in p0) are involved in binding.
However, these binding sites play different roles in the catalytic process of
ribonuclease A. The electrostatic interactions in p2 are important both in
catalysis and in the endonuclease activity of the enzyme, whilst the p0
electrostatic interaction contributes only to binding of the RNA.
PMID- 9760986
TI - Biochemistry of frog ribonucleases.
AB - Frogs have unique pyrimidine base-specific RNases, with structures similar to
those of turtle, iguana and chicken RNases. Among the four frog RNases discussed
here, three from Rana pipiens, R. catesbeiana and R. japonica oocyte cells show
antitumour activity, and the latter two show lectin activity towards sialic acid
rich glycoproteins. In this review, (i) we compare their unique primary
structures with respect to the locations of their disulphide bridges, three
dimensional structure, base specificity and heat stability as compared with RNase
A, and (ii) we summarize current knowledge about the mode of action of lectin and
the antitumour activities of the three frog RNases.
PMID- 9760987
TI - Human extracellular ribonucleases: multiplicity, molecular diversity and
catalytic properties of the major RNase types.
AB - Human extracellular ribonucleases (RNase), together with other members of the
mammalian RNase A superfamily, can be classified into four different RNase
families on the basis of their structural, catalytic and/or biological
properties. Their occurrence and main distinctive features have been described,
and the information available on their catalytic properties has been analysed and
discussed in comparison with those of other animal RNases. On the basis of some
results obtained with various single- and double-stranded polyribonucleotides, it
has been proposed that while pancreatic-type (pt) RNases could be defined as
single-strand/pyrimidine 'preferring' ribonucleases, mammalian nonpancreatic-type
(npt) RNases may be referred to as single-strand/pyrimidine 'specific'
ribonucleases. In addition, some data concerning human nptRNases may support the
suggestion [Cuchillo et al. (1993) FEBS Lett. 333: 207-210] that the enzyme
'ribonuclease' should be reclassified as 'transferase'.
PMID- 9760988
TI - The eosinophil ribonucleases.
AB - The eosinophil ribonucleases, eosinophilderived neurotoxin (EDN/RNase 2) and
eosinophil cationic protein (ECP/RNase 3) are two closely related proteins with
intriguing functional and evolutionary properties. While both EDN and ECP
maintain the structural and catalytic residues typical of the RNase A
superfamily, the role of ribonuclease activity in the physiologic function of
these proteins remains unclear. The biochemistry and physiology of EDN, ECP and
the recently discovered ribonuclease k6 (RNase 6) will be reviewed in this
chapter.
PMID- 9760989
TI - Ribonuclease 4, an evolutionarily highly conserved member of the superfamily.
AB - The structural and enzymatic properties of RNase 4 are reviewed. This RNase shows
a much higher interspecies similarity (approximately 90%) than the other members
of the RNase A superfamily. The enzyme is ubiquitous, with the highest amounts
present in liver and lung. Its unique uridine specificity results from
alterations in and around the pyrimidine-binding site. In particular, the
shortened C-terminus and the side chains of Phe-42, Asp-80 and Arg-101 appear to
be involved. RNase 4 binds tightly to the intracellular RNase inhibitor, with a
Kd of 4 x 10(-15) M.
PMID- 9760990
TI - The angiogenins.
AB - The angiogenic and other biological functions of the angiogenins, members of the
pancreatic RNase superfamily of proteins, are reviewed in the context of their
primary and tertiary structures. The ribonucleolytic activity and interactions
with the placental ribonuclease inhibitor have seen much study in the last few
years. The mechanism of the angiogenic activity of angiogenin has recently been
postulated as involving multiple interactions with other proteins through
specific regions on the molecular surface of angiogenin. These molecular partners
include heparin, plasminogen, elastase, angiostatin, actin and most importantly a
170-kilodalton receptor on subconfluent endothelial cells. The existence of the
latter receptor was established in conjunction with a mitogenic activity of
angiogenin on subconfluent cells. The levels of angiogenin in various
physiological and disease states are summarized, including various studies on
pregnancy and angiogenin. Correlations are seen between states of enhanced
angiogenesis and angiogenin levels. An overview of the relationship of angiogenin
and the other RNases of the superfamily showed that their genes all are in
relative close proximity on human chromosome 14. Examination of the many
expressed sequence tags published in the public databanks, for angiogenin and the
other RNases, revealed that angiogenin and RNase-4 (the most evolutionarily
conserved RNase), share various identical 5'-untranslated regions on their sets
of messenger RNAs, suggesting that their genes are in very close proximity on
chromosome 14 and that they are products of differential splicing. This in turn
suggests that, in both humans and mice, expression of these two proteins is under
identical control, with obvious implications for their biological activities. The
evolutionary history of the angiogenins is examined briefly on the basis of the
protein sequences of the human, rabbit, pig, two bovine and four mouse
angiogenins, and two mouse angiogenin pseudogene sequences. The discrepancy
between the conventional requirement for conservatism in structure to allow
multimolecule interactions, and the actual fast-changing sequence of the
angiogenins, in concert with the wide-ranging activity even in birds, of human
angiogenin, is discussed.
PMID- 9760991
TI - The ribonuclease A superfamily: general discussion.
AB - Enzymic properties of members of the ribonuclease A superfamily, like the
activity on RNA, the preference for either cytosine or uracil in the primary
binding site B1, the preference for the other side of the cleaved phosphodiester
bond, the B2 site, and features of the two noncatalytic phosphate-binding sites
P0 and P2 are discussed in several articles in this multi-author review, and are
summarized in this closing article. A special feature of members of the
ribonucleases 1 family is their destabilizing action on double-stranded nucleic
acid structures. A feature of the ribonuclease A superfamily is the frequent
occurrence of gene duplications, both in ancestral vertebrate lineages and in
recently evolved taxa. Three different bovine ribonucleases 1 have been
identified in pancreas, semen and brain, respectively, which are the result of
two gene duplications in an ancestral ruminant. Similar gene duplications have
been identified in other ribonuclease families in several mammalian and other
vertebrate taxa. The ribonuclease family, of which the human members have been
assigned numbers 2, 3 and 6, underwent a still mysterious pattern of gene
duplications and functional expression as proteins with ribonuclease activity and
other physiological properties.
PMID- 9760992
TI - Bacterial nonspecific acid phosphohydrolases: physiology, evolution and use as
tools in microbial biotechnology.
AB - Bacterial nonspecific acid phosphohydrolases (NSAPs) are secreted enzymes,
produced as soluble periplasmic proteins or as membrane-bound lipoproteins, that
are usually able to dephosphorylate a broad array of structurally unrelated
substrates and exhibit optimal catalytic activity at acidic to neutral pH values.
Bacterial NSAPs are monomeric or oligomeric proteins containing polypeptide
components with an M(r) of 25-30 kDa. On the basis of amino acid sequence
relatedness, three different molecular families of NSAPs can be distinguished,
indicated as molecular class A, B and C, respectively. Members of each class
share some common biophysical and functional features, but may also exhibit
functional differences. NSAPs have been detected in several microbial taxa, and
enzymes of different classes can be produced by the same bacterial species.
Structural and phyletic relationships exist among the various bacterial NSAPs and
some other bacterial and eucaryotic phosphohydrolases. Current knowledge on
bacterial NSAPs is reviewed, together with analytical tools that may be useful
for their characterization. An overview is also presented concerning the use of
bacterial NSAPs in biotechnology.
PMID- 9760993
TI - The effect of monensin and chloroquine on the endocytosis and toxicity of
chimeric toxins.
AB - The toxicity of two conjugates containing ribosome-inactivating proteins (RIPs,
i.e. saporin and ricin-A chain x-linked to transferrin) has been measured on a
prostatic cancer line (PC3) naturally overexpressing the transferrin receptor, in
the presence of monensin and chloroquine. This paper investigates whether the
increased toxicity of Tf-RIPs induced by monensin and chloroquine may be due to
alterations of the normal endocytotic pathway of the complexes mediated by the
transferrin receptor. Monensin, besides inducing alkalinization of normally acid
intracellular compartments, causes an accumulation of the receptor-bound Tf-RIP
in a perinuclear region contiguous to the cisternae of the trans-Golgi network.
Chloroquine, though increasing the intracellular pH, seems not to modify the
endocytotic pathway of these chimeric molecules. We believe that the enhanced
toxicity of the Tf-RIPs may be related to intracellular alkalinization (i.e.,
endosomal or lysosomal pH) rather than to the effects on the recycling of
transferrin receptor-bound toxins. We conclude that the efficacy of chimeric
toxins may be modulated not only by the carrier used for their engineering but
also by addition of drugs able to influence the stability and activation of the
toxins inside the cell.
PMID- 9760994
TI - The V(D)J recombination activating protein RAG2 consists of a six-bladed
propeller and a PHD fingerlike domain, as revealed by sequence analysis.
AB - The RAG1 and RAG2 proteins play a crucial role in V(D)J recombination by
cooperating to make specific double-stranded DNA breaks at a pair of
recombination signal sequences (RSSs). However, the exact function they perform
has heretofore remained elusive. Using a combination of sensitive methods of
sequence analysis, we show here that the active core region of the RAG2 protein,
confined to the first three quarters of its sequence, is in fact composed of a
six-fold repeat of a 50-residue motif which is related to the kelch/mipp motif.
This motif, which forms a four-stranded twisted antiparallel beta sheet, is
arranged in a circular formation like blades of a propeller or turbine. Given the
known properties of the beta-propeller fold in mediating protein-protein
interactions, it is proposed that this six-laded propeller structure of the RAG2
active core would play a crucial role in the tight complex formed by the RAG1 and
RAG2 proteins and RSSs. Moreover, the presence of a plant homeodomain finger-like
motif in the last quarter of the RAG2 sequence suggests a potential interaction
of this domain with chromatin components.
PMID- 9760995
TI - Genetics of the febrile seizure susceptibility trait.
AB - Febrile seizures are the commonest form of convulsion, occurring in 2-5% of
infants in Europe and North America and 6-9% of infants in Japan. In large
families, the febrile seizure susceptibility trait is inherited by the autosomal
dominant pattern with reduced penetrance. In the other families, inheritance
appears to be multifactorial. Recent linkage studies provide evidence that
regions of chromosomes 8 and 19 contain febrile convulsions (FC) susceptibility
genes. This opens up the way to cloning a febrile seizure gene and determining
the contributions of these gene loci to febrile seizures in the sporadic cases
and the small families. Cloning a febrile seizure gene will make possible new
approaches to prevention and therapy. It will also be possible to determine
whether a febrile seizure gene contributes to other types of seizures.
PMID- 9760996
TI - Advances in pediatric neuroimaging.
AB - Magnetic resonance evaluation of the pediatric central nervous system is rapidly
improving in a number of ways: (1) anatomically with higher resolution; (2) with
greater sensitivity to pathological processes characterized by increased water
content utilizing fluid attenuated inversion recovery imaging (FLAIR); (3) with
greater speed of acquisition with ultrafast (1 s/image) and echo planar imaging
techniques (50 ms/image); (4) with measurement of cerebral blood flow as
perfusion; (5) with measurement of water proton dispersion (e.g. diffusion
imaging); (6) with measurement of biochemical components within tissues with
proton spectroscopy; and (7) with evaluation of cortical activation with
functional magnetic resonance imaging.
PMID- 9760997
TI - Neuronal intranuclear inclusion disease: neuropathologic study of a case.
AB - We report neuropathological findings in a 22-year-old man affected with neuronal
intranuclear inclusion disease. The inclusions affected to different extents the
various structures of the central nervous system, being more numerous in cerebral
cortex, inferior olives, hypoglossal and oculomotor nuclei. They
ultrastructurally differed from Marinesco bodies. In the neurons of the
substantia nigra, we occasionally observed intranuclear inclusions resembling the
so-called rodlets of Roncoroni. We did not observe inclusions in the
extraneuronal tissues. There was no apparent correlation between frequency of the
inclusions and neuronal loss. Intranuclear inclusions were found in many
morphologically normal neurons. We suggest that the intranuclear inclusions are
the marker of a distinctive disorder, even though their role in neuronal
degeneration remains to be clarified.
PMID- 9760998
TI - Fluoro-2-deoxyglucose (18FDG) PET scan of the brain in glutaric aciduria type 1:
clinical and MRI correlations.
AB - The clinical, PET (positron emission tomography) and MRI (magnetic resonance
imaging) findings of brain studies in eight patients, previously diagnosed to
have glutaric aciduria type 1, were retrospectively reviewed. The neurological
findings typically consisted of variable degrees of dementia and extrapyramidal
symptoms (dystonia, choreoathetosis and rigidity). Both MRI and PET showed
involvement of the putamina in all the patients. The PET scan demonstrated
lesions in the head of the caudate nuclei in all of the patients. Brain atrophy,
and in particular the characteristically-enlarged Sylvian fissures, was better
demonstrated by MRI. On the other hand, the cerebral cortex and thalamic
structures were found to be normal by MRI in all patients, whereas PET scan
showed decreased uptake in the cerebral cortex in seven, and in the thalami in
three patients. Correlation between imaging and clinical findings was found to be
good when both PET scan and MRI findings of the brain were taken into
consideration. Therefore, the functional (PET) and structural (MRI) studies of
the brain were complementary in the imaging evaluation of glutaric aciduria type
1.
PMID- 9760999
TI - Increased expression of beta-hexosaminidase alpha chain in cultured skin
fibroblasts from patients with carbohydrate-deficient glycoprotein syndrome type
I.
AB - Carbohydrate-deficient glycoprotein (CDG) syndrome type I is an autosomal
recessive multisystem disorder characterized by multiple serum glycoproteins with
deficient oligosaccharide chains. This characteristic under-glycosylation is
found in several serum glycoproteins. We studied secreted forms of lysosomal
enzymes, beta-hexosaminidase and alpha-fucosidase, in serum from the patients and
media of cultured fibroblasts. Both beta-hexosaminidase and alpha-fucosidase
activities were increased in sera from three CDG patients. The enzyme activity
staining using the fluorogenic substrate-4-methylumbelliferyl-alpha-L
fucopyranoside after polyacrylamide gel isoelectric focusing revealed abnormal
cathodal bands in sera from CDG patients. On the other hand, no abnormal secreted
forms of beta-hexosaminidase and alpha-fucosidase were detected in media from
cultured CDG fibroblasts by isoelectric focusing and sodium-dodecyl sulfate
polyacrylamide gel electrophoresis. However, SDS-polyacrylamide gel
electrophoresis and Western blotting analysis of beta-hexosaminidase using anti
beta-hexosaminidase A (anti-alpha + beta chains) antibody, showed an increase of
a 55-kDa mature form of the alpha chain. Northern blotting analysis identified an
increase in mRNA levels of beta-hexosaminidase alpha chain in CDG fibroblasts.
Although under-glycosylated fractions of these lysosomal enzymes were not
detected in cultured fibroblasts, it was suggested that intracellular processing
of these lysosomal enzymes in CDG patients might be altered.
PMID- 9761000
TI - Using postural reactions as a screening test to identify high-risk infants for
cerebral palsy: a prospective study.
AB - To clarify the predictive value of the seven more commonly used postural
reactions (PR) in the 1st year of life regarding the diagnosis of cerebral palsy
(CP), we prospectively examined 204 high-risk infants of whom 58 developed CP, 22
had developmental retardation (DR) and 124 were normal at follow-up at 3 years of
age. Abnormalities of five or more PR from the 1st month of life were correlated
with spastic CP, while five or six abnormal PR were also correlated with athetoid
CP. Three or less abnormal PR correlated with a normal outcome. All seven PR
tested were significantly abnormal in children with spastic CP from the 1st month
compared to normal children. Athetoid children demonstrated abnormalities of the
Peiper-Isbert (P-I) reaction and Vojta reaction from the 1st month and of the
vertical, horizontal and Collis vertical suspension from the 3rd month. Children
with DR had significantly abnormal Collis horizontal and Collis vertical
suspension, Vojta reaction and traction response from the 1st month and Peiper
Isbert reaction from the 3rd month. Ataxic children demonstrated significantly
abnormal traction response from the 1st month, Collis horizontal reaction from
the 7th month and Peiper-Isbert reaction from the 11th month. We conclude that
the examination of PR is a useful quantitative and qualitative diagnostic
screening tool for high-risk infants from the 1st month of life.
PMID- 9761001
TI - Adrenocorticotropic hormone therapy for infantile spasms alters pyruvate
metabolism in the central nervous system.
AB - To clarify the mechanism of action of adrenocorticotropic hormone (ACTH) in
treating infantile spasms, we evaluated the effects of ACTH on the metabolism of
pyruvate in the central nervous system (CNS) of children with infantile spasms.
We measured the levels of lactate and pyruvate in cerebrospinal fluid (CSF) and
serum, before and during ACTH treatment in 12 children with infantile spasms. We
evaluated statistically any correlation between the observed metabolic changes
and the clinical response of ACTH. ACTH therapy significantly elevated the levels
of lactate and pyruvate in the CSF and serum. The effect was not dose-dependent.
During ACTH therapy, the serum levels of lactate and pyruvate and the ratio of
lactate to pyruvate (L:P ratio) were unrelated to these levels in CSF. Patients
who showed a good initial response to treatment had a significantly higher CSF
level of pyruvate and a lower L:P ratio during therapy than did those with a poor
initial response. This is the first report that ACTH therapy administered for
infantile spasms alters pyruvate metabolism in the CNS. This metabolic change may
be involved in part in the action of ACTH in relieving infantile spasms.
PMID- 9761002
TI - Subdural hygroma in association with middle fossa arachnoid cyst: acetazolamide
therapy.
AB - Intracranial arachnoid cysts are cerebrospinal fluid-filled collections between
arachnoid layers. While many are silent, arachnoid cysts can become symptomatic
if there is sudden expansion, haemorrhage or rupture with the development of
subdural hygroma or subdural hematoma. Several studies have demonstrated the
association of arachnoid cysts with subdural hygroma and subdural hematoma. We
describe a 9-year-old girl with a moderate-sized middle-fossa arachnoid cyst and
bilateral frontal subdural hygroma presenting with raised intracranial pressure.
She was treated with acetazolamide which resulted in resolution of the subdural
hygroma and relief of symptomatology.
PMID- 9761003
TI - Workshop on Autonomic Function in Rett Syndrome. Swedish Rett Center Froson,
Sweden, May 1998.
PMID- 9761004
TI - The influence of inhaled corticosteroids on bone mineral density in asthmatic
children.
PMID- 9761005
TI - Asthma and atopy in Western and Eastern communities--current status and open
questions.
PMID- 9761006
TI - A safe, simple, standardized method should be used for sputum induction for
research purposes.
PMID- 9761007
TI - The COX-1/COX-2 balance in asthma.
PMID- 9761008
TI - Molecular mechanisms of leukotriene synthesis: the changing paradigm.
PMID- 9761009
TI - Bone mineral density and body composition in patients with airflow obstruction-
the role of inhaled steroid therapy, disease and lifestyle.
AB - BACKGROUND: Inhaled steroid therapy has been shown to be associated with low bone
mineral density (BMD) in asthmatic patients, but its effect in men has not been
specifically studied; and the relative importance of therapy, disease and
lifestyle leading to low BMD has not been investigated. OBJECTIVES: The study was
designed to compare BMD in women and men who had airflow obstruction (asthma or
COAD with or without inhaled steroid therapy) with normal controls. The role of
inhaled steroid treatment, disease severity and lifestyle was studied among
patients. METHODS: One hundred and fourty-four patients (106 on inhaled steroids
and 38 not on inhaled steroids) and 212 age-matched controls were studied. Body
composition and BMD (at the total body, hip and spine) were measured by dual-X
ray densitometry (DEXA). Forced expiratory volume (FEV1) was measured in
patients. A validated questionnaire was administered to measure lifestyle
factors. RESULTS: The body mass indices (BMI) (P < 0.001) and percentage of body
fat (P < 0.001) were higher among female patients on inhaled steroids than
controls. However, the BMD of the total body (P < 0.05) and spine (P < 0.001)
were significantly lower in premenopausal and postmenopausal women than controls,
respectively (P < 0.005). The BMD at the spine (P<0.01) and hip (P < 0.01) in
male patients were significantly lower than the controls. By multiple regression,
age and use of inhaled steroid was negatively associated with BMD at the hip (P <
0.01), but not at the spine (P>0.05). Cigarette smoking was associated with
significantly lower BMD at the femoral neck (P < 0.05), and a low dietary calcium
intake was associated with lower BMD at the spine (P<0.05). In women, use of
inhaled steroid was not associated with significantly lower BMD. CONCLUSION: Men
who had asthma and/or COAD had lower BMD, and this was not attributable entirely
to steroid use. Cigarette smoking and a low dietary calcium intake may partially
account for this difference. The difference in BMD between female patients and
controls, even in those taking inhaled steroid, was small.
PMID- 9761010
TI - Atopy and allergic disorders among adults in Tartu, Estonia compared with
Uppsala, Sweden.
AB - BACKGROUND: Recent studies in children and adults indicate that the prevalence of
atopy and allergic disorders is lower in previously socialist countries in
Eastern Europe compared with countries with a market economy while revealed risk
factors are similar. OBJECTIVES: To estimate the prevalence of atopy among adults
in Tartu, Estonia and to compare the prevalence of risk factors for atopy and
allergic respiratory diseases in Estonia and Sweden. METHODS: As a part of cross
sectional study-European Community Respiratory Health Survey-random samples of 20
44 year olds (n = 351 in Tartu and n = 470 in Uppsala) and persons of the same
age with asthma like symptoms or on current asthma medication according to a
postal questionnaire (n = 95 in Tartu and n = 201 in Uppsala) were interviewed
and circulating IgE antibodies were measured. RESULTS: The prevalence of atopy
was 19% in Tartu and 32% in Uppsala (P < 0.001). The prevalence of sensitization
to pollen was twice lower (11.5 vs 23.2; P<0.001) and the prevalence of pollen
associated asthma symptoms was four times lower (1.7 vs 6.8; P<0.001) in Tartu
than in Uppsala while sensitization to pollen was an equally large risk factor
for asthma in both centres. Age was inversely related to cat and pollen
associated symptoms of rhinoconjunctivitis in Uppsala (OR 0.6 and 0.7,
respectively, P < 0.05) but not in Tartu. CONCLUSIONS: The prevalence of atopy
was lower in Tartu, Estonia than in Uppsala Sweden. Perception of allergic
disorders seemed to be lower in Tartu than in Uppsala. Age did not influence the
prevalence of atopy nor allergic disorders in Tartu, while in Uppsala age was
inversely related to clinical allergy. This could suggest a cohort effect
underlying the increasing prevalence of allergy in Western Europe.
PMID- 9761011
TI - Induced sputum eosinophil cationic protein (ECP) measurement in asthma and
chronic obstructive airway disease (COAD)
AB - BACKGROUND: Induced sputum is a useful way to monitor airway inflammation in
asthma, but cell counts are time-consuming and labour intensive. OBJECTIVE: The
aim of this study was to evaluate a novel processing method using eosinophil
cationic protein (ECP) as a biochemical marker of sputum eosinophil number and
activation in subjects with asthma and other airway diseases. METHODS: Sputum was
dispersed with dithiothreitol and centrifuged to yield cell free supernatant and
a cell pellet. The pellet was treated with a cellular lysis buffer to release
cell-associated ECP. ECP was measured in sputum supernatant and in the lysed cell
pellet and was compared with sputum eosinophil counts in 31 adults with asthma,
chronic obstructive airway disease (COAD), bronchiectasis and healthy controls.
The ratio of supernatant to pellet ECP was evaluated as an index of eosinophil
degranulation. The effect of sputum processing reagents and storage time on ECP
measurement was also evaluated. RESULTS: ECP measured in the cell pellet lysate
correlated closely with sputum absolute eosinophil counts across a range of
subject groups (r = 0.72, P = 0.004). Sputum eosinophil counts were less well
correlated with supernatant ECP levels (r = 0.54, P < 0.05). Incubation with
dithiothreitol or lysis buffer did not influence ECP measurement and sputum ECP
levels were stable over a 6-9 month period. Sputum supernatant and pellet lysate
ECP concentrations were increased in stable asthma, asthma exacerbations and
COAD/bronchiectasis (P < 0.05). The ratio of supernatant to pellet ECP was used
as an index of eosinophil degranulation and found to be elevated in asthma
exacerbations, COAD and bronchiectasis, but not in stable asthma. CONCLUSION: The
measurement of ECP in the sputum cell pellet provides a reliable and efficient
estimate of sputum eosinophil counts which can potentially be used in clinical
trials and epidemiological surveys. The ECP ratio may be a useful marker of
eosinophil activation, and was increased in asthma exacerbation and COAD. The
increased ECP in COAD reflects a non-selective accumulation of eosinophils in
this condition.
PMID- 9761012
TI - Asthma, rhinitis and eczema in Maltese 13-15 year-old schoolchildren --
prevalence, severity and associated factors [ISAAC]. International Study of
Asthma and Allergies in Childhood.
AB - BACKGROUND: Allergic conditions, especially asthma, seem to be increasingly
common the world over. The International Study of Asthma and Allergies in
Childhood [ISAAC] was the first worldwide study carried out with standardized
questionnaires in order to create a reliable global map of childhood allergy.
OBJECTIVES: The Maltese Islands were one of the centres participating in this
study and in this paper the data obtained from 4184 13-15 year olds from 22 state
and three private schools [88.7% response rate], and also data obtained from some
added 'local' questions addressed to the same children, are included. in order to
evaluate the problem of allergic conditions in Maltese schoolchildren. RESULTS:
27.9% of the participants were wheezers 'ever' while 16% were current wheezers.
Of the latter children 15.1% were experiencing nocturnal wheezing at least once a
week and 22% had a wheezing episode severe enough to limit speech. Nasal problems
were present in 52.7% of these teenagers and 47.4% of all respondents persisted
with these symptoms up to the year of answering the questionnaire. Hayfever had
been diagnosed in 32.3% of all the children. 12.8% of respondents had a recurring
itchy rash suggestive of eczema for at least 6 months of their lives and 10% had
it currently. This was slightly lower than the global mean, unlike the case of
wheezing, which in Malta was more common than the world average, and rhinitis,
for which we had the second highest cumulative prevalence rate in the world.
Multiple variables such as gender, smoking, family history of atopy, pets, soft
furnishings and living in busy roads affected the prevalence and severity of the
allergic conditions studied. CONCLUSIONS: Allergic conditions are very common in
Maltese schoolchildren and are causing a lot of hardship to these same
youngsters. The results of this study should serve as a stimulus to try and
decrease this suffering through better management of these conditions, measures
to control possible detrimental factors and further research on asthma, allergic
rhinitis and eczema.
PMID- 9761013
TI - Dermatophagoides sp. and IgE anti-D. pteronyssinus and D. farinae detection in a
Venezuelan community at more than 2000 m above the sea level.
AB - BACKGROUND: It has been reported that the concentration of Dermatophagoides sp.
population, the main trigger of asthma in sensitized atopic subjects, is
inversely related with altitude and probably directly with humidity and that this
population are scarcely found over 1750 m above sea level. OBJECTIVE: We studied
the presence of Dermatophagoides sp. in a Venezuelan community between 2040 and
2600 m above sea level, and also the IgE response to D. pteronnyssinus and D.
farinae in atopic subjects living on that region. METHODS: The presence of
Dermatophagoides sp. was determined by microscopic identification of mites in
dust, obtained by brushing the mattresses surface in 93 randomly selected houses
between 2040 and 2600 m above sea level. The indoor relative humidity was also
measured. The specific IgE serum levels were studied in 65 subjects classified as
asthmatics, allergic non-asthmatics and non-allergic. RESULTS: A mean
concentration of 188 mites/g of room dust was determined in 82.4% of houses with
an indoor relative humidity ranging from 89% and 92% independently of altitude.
The density of Dermatophagoides sp. was sufficiently high to sensitize the atopic
subjects, IgE levels were 6.8 PRU mean value for asthmatic, against 0.38 PRU in
non-atopic. CONCLUSIONS: We conclude that: (a) Dermatophagoides sp. can be found
up to 2600 m above sea level in a Venezuelan neotropical region where a high
indoor relative humidity is characteristic of most dwellings; (b) sensitization
by D. pteronyssinus and D. farinae were demonstrated in atopic subjects resident
at that region.
PMID- 9761014
TI - Direct measurements of temperature and humidity in dust mite microhabitats.
AB - BACKGROUND: Up to 70% of atopic asthmatics have a positive skin test to the dust
mite allergen Der p 1. Reduction of dust mite numbers by lowering room humidity
control is one suggested technique for reducing dust mite allergen levels to
clinically acceptable levels. Trials of this technique in temperate climates have
reported mixed results. It has been speculated that one reason for this is that
humidity changes in room ambient air are not tightly linked to humidity changes
in the dust mite microenvironment (in the base of carpets, bedding, furniture
etc.). OBJECTIVE: To directly measure humidities and temperatures in dust mite
microenvironments and compare these to ambient conditions, and so gather data on
how the microclimates are influenced by room conditions and moisture and heat
sources, such as an occupant in a bed. METHODS: A special small humidity device
has been developed which can discriminate humidity changes over distances of
millimetres. With these devices microclimates have been measured in the base of
carpets, in layers through bedding, and in furniture. RESULTS: Measured base-of
carpet humidities were significantly higher than room humidities. Bedding
relative humidities show complex behaviour according to the distance separation
between the measuring point and the occupant. Immediately below the occupant, bed
relative humidities fall when the person enters the bed. Similar behaviour is
observed in a sofa. CONCLUSION: Some dust mite microclimates have been shown to
be very different from room conditions. Consequently, reduction of dust mite
numbers and allergen levels cannot be guaranteed by the controlling of room
humidities.
PMID- 9761015
TI - Food allergy to peanuts in France--evaluation of 142 observations.
AB - BACKGROUND: The increase in frequency of peanut allergy and fatal cases have been
reported. OBJECTIVES: The objective of this study is to document the severity of
food allergy to peanuts by evaluating the reactive dose of peanuts and to search
for the role of peanut oil. METHODS: This study is carried out on the basis of
142 observations collected according to the same diagnostic methodology in two
allergy centres in France. Skin-prick-tests were performed with peanut powder,
peanut oil and peanut oil proteinic extract. Labial provocation tests were
performed on 121 patients. The reactive dose of peanuts and the role of peanut
oil were determined by standardized oral provocation tests in 50 and 62 patients
respectively. The data are computerized and the data bank includes 509 food
allergic patients. RESULTS: Allergy to peanuts represents 28% of food allergies
and occurs under 1 year of age in 46% of cases, under 15 years of age in 93%. The
clinical features were atopic dermatitis (40%), angioedema (37%), asthma (14%),
anaphylactic shock (6%) and digestive symptoms (1.4%). The specific IgE were
class 3 or higher in 80% of cases. The total reactive dose was less than 100 mg
in 25% of cases, from 100 mg to 1 g in 62.5%. All patients reacted to a dose of
less than 7.1 g. The threshold of peanut reactivity was lower than the threshold
of egg reactivity. An allergy to peanut oil was demonstrated in 14 patients.
CONCLUSION: The severity of peanut allergy and the early onset of the occurrence
of this allergy is documented. The role of residual allergenic proteins in peanut
oil is established by positive skin-prick tests to proteic extracts from peanut
oil and by double-blind placebo-controlled challenges to peanut oil. The
increased consumption of allergens in the form of peanut oil and fats can
contribute to the occurrence or persistence of symptoms and may be suspected to
increase the risk of sensitisation.
PMID- 9761016
TI - Correlation between antigen-specific IL-2 response test and provocation test for
egg allergy in atopic dermatitis.
AB - BACKGROUND: The antigen-specific interleukin-2 response (AIR) test using
lymphocytes is effective in searching for the antigen which causes allergic
diseases and understanding their disease activity. OBJECTIVE AND METHODS: The
correlation between the raw egg oral provocation test and egg white antigen
specific interleukin-2 (IL-2) response test was investigated in 123 children with
infantile atopic dermatitis and 13 children with bronchial asthma. RESULTS: Among
the 83 who showed positive reactions to provocation, 75 also reacted positively
to the AIR test (sensitivity, 90.4%), while among the 53 children who showed
negative responses to antigen provocation, 45 produced negative responses to the
AIR test (specificity, 84.9%). The specificity of egg white IgE RAST score and
skin-prick test are 88.7 and 81.3% which are comparable to that of the AIR test.
However, their sensitivity was low (38.6 and 66.7%). In the patterns of symptom
developed in the provocation AIR displayed late and delayed type allergic
responses in addition to the immediate type which RAST reflected. The RAST
negative group composed of 98 patients included 51 (52.0%) who exhibited positive
reactions to the provocation test. Among these 44 responded positively to the AIR
test (86.3%). CONCLUSION: The AIR test is effective for screening egg white
antigen as part of the tests for antigens responsible for allergic diseases and
as a test to ascertain the relevant antigens, and that the conditions that could
not be diagnosed by RAST can be detected by the AIR test.
PMID- 9761017
TI - Allergenic and antigenic activity of peptide fragments in a whey hydrolysate
formula.
AB - BACKGROUND: Milk hydrolysates, although frequently used as substitutes in cases
of cow's milk allergy, show a reduced but never a complete abolishment of
antigenicity and allergenicity. OBJECTIVE: Our purpose was to determine the lower
molecular weight limit of peptides to elicit skin reactions and to bind IgE
antibodies in vitro. METHODS: Using FPLC, an ultrafiltrated whey hydrolysate, was
fractionated in different molecular weight fractions. Skin-prick tests were
performed with the hydrolysate and its fractions in five cow's milk allergic
children, and RAST inhibition tests were done using the serum of these children.
RESULTS: On the basis of the lowest extinction values between two peaks of the
chromatogram, seven fractions with molecular weights between 15000 and 125 Da
were obtained. Peptides of > 2600 Da elicited a clearly positive skin reaction
and inhibited IgE-binding, while peptides of < 1400 Da did not give any positive
skin reaction but were still able to inhibit to a small extent IgE-binding to the
hydrolysate. CONCLUSION: Our findings suggest that for skin reactivity peptides
of > 1400 Da are needed. The minimal molecular mass for IgE binding in vitro
appears to be situated between 1400 and 970 Da. Such peptides might be used to
develop a safe formula for patients reacting to milk hydrolysates or even for
tolerance induction.
PMID- 9761018
TI - Correlation among urinary eosinophil protein X, leukotriene E4, and 11
dehydrothromboxane B2 in patients with spontaneous asthmatic attack.
AB - Various kinds of cells and their mediators are thought to be involved in the
pathogenesis of bronchial asthma. However, changes in each mediator or
relationship among mediators during an asthmatic attack have not been well
documented. In this study, to clarify whether eosinophil protein X (EPX) is a
marker which is distinct from leukotriene E4 (LTE4), or 11-dehydrothromboxane B2
(11DTXB2), we measured the urinary excretion of EPX, LTE4, and 11DTXB2 in 14
asthmatics who were admitted to the hospital with either an acute asthmatic
attack or status asthmaticus. These patients included eight atopic and six non
atopic types of bronchial asthma, with a median age of 34.0 years. Urinary
excretion of EPX was significantly high on admission with the asthmatic attack,
and returned to control levels 175 [122 -384] microg/day when the patients were
in the improved state (1036-317 microg/day, P < 0.01). Similar findings were
observed in LTE4 (155-59 ng/day, P < 0.01) and 11DTXB2 (991-442ng/day, P<0.01).
No significant differences in values were observed between atopic and non-atopic
types of asthma in all three substances. When the individual data during the
attack state were analysed, a significant correlation was observed between
changes (%) in urinary EPX and those in urinary LTE4, but no such relationship
was observed between changes (%) in urinary EPX and those in urinary 11DTXB2.
These results suggest that measuring urinary EPX levels may be a useful marker
for the understanding and management of the disease.
PMID- 9761019
TI - GM-CSF, IL-5 and RANTES immunoreactivity and mRNA expression in chronic
hyperplastic sinusitis with nasal polyposis (NP).
AB - BACKGROUND: Eosinophils are a prominent feature of chronic hyperplastic sinusitis
with nasal polyposis (CHS/NP). Our previous studies showed that their presence
was associated with the expression of GM-CSF and RANTES mRNA. In allergic NP,
increased expression of IL-5 was also found. OBJECTIVE: We wished to examine
cytokine immunoreactivity for IL-5, GM-CSF and RANTES mRNA in allergic and non
allergic NP and compare immunoreactivity with expression of cytokine mRNA by in
situ hybridization. Methods NP were obtained from five allergic and eight non
allergic subjects with CHS/ NP. Middle turbinate tissue from eight normal
subjects were used as controls. Cell-associated cytokine mRNA was detected by in
situ hybridization (ISH). Cytokine immunoreactive cells were enumerated by
immunostaining. Colocalization immunostaining was also performed to identify
specific cell types producing IL-5. RESULTS: Immunostaining for GM-CSF, IL-5 and
RANTES protein was increased in both allergic and non-allergic NP compared with
control middle turbinates. Allergic polyps contained greater numbers of IL-5
immunoreactive cells (P = 0.01), whereas non-allergic polyps contained greater
numbers of GM-CSF immunoreactive cells (P = 0.04). Immunostaining was primarily
associated with inflammatory cells, but immunostaining for RANTES and, to a
lesser extent GM-CSF, was also seen in the epithelium. The density of
immunoreactive cells was variably correlated with cytokine mRNA+ cells (GM-CSF:
R=0.56, P=0.05; IL-5: R=0.76, P=0.003; and RANTES: R=0.89, P=0.0005).
Colocalization immunostaining revealed that the majority of IL-5 immunoreactive
cells in both allergic and non-allergic NP were T lymphocytes. However, allergic
NP contained greater numbers of IL-5+/CD3+ T lymphocytes and IL-5+ mast cells,
whereas non-allergic NP contained greater numbers of IL-5+ eosinophils.
CONCLUSION: We conclude that GM-CSF, IL-5 and RANTES are produced in increased
amounts in both allergic and non-allergic NP. Distinguishing features of non
allergic NP include fewer numbers of CD3 T lymphocytes, fewer IL-5+/CD3+ T
lymphocytes and greater numbers of IL-5+ eosinophils. These differences may
suggest different mechanisms of eosinophil accumulation and activation in
allergic vs non-allergic NP.
PMID- 9761020
TI - Association of pyrazolone drug hypersensitivity with HLA-DQ and DR antigens.
AB - BACKGROUND: In sensitive patients pyrazolone drugs can precipitate adverse
reactions ranging from urticaria and angioedema to anaphylactic shock, presumably
by immunological, IgE-mediated mechanism. However, up to now no genetic factors
influencing the development of allergic reaction have been reported in this type
of hypersensitivity. OBJECTIVE: The aim of our study was the investigation
whether the susceptibility to development of pyrazolone drugs hypersensitivity
(PDH) reactions was associated with HLA class II antigens. METHODS: To test this
hypothesis we studied the distribution of HLA-DR and DQ antigens in 26 pyrazolone
sensitive patients and control groups including unselected general population and
clearly defined atopic and non-atopic groups. RESULTS: Significantly higher
frequencies of DQ 7 and DR11 antigens were found in PDH group as compared with
control unselected population (RR= 16.48, P < 0.0001; P(cor)< 0.002 and RR =
4.57, P = 0.0002; Pcor = 0.003 for DQ and DR antigen respectively). Similarly,
statistically significant increased frequencies of DQ 7 and DR11 in patients with
PDH were observed compared with atopic control group (RR= 18.43, P < 0.0001; Pcor
<0.002 and RR= 6.33, P= 0.0007; Pcor =0.01, for DQ and DR antigen respectively).
However, in comparison to non-atopic control group only the frequency of DQ 7
antigen was significantly increased (RR = 15.42, P = 0.0001; Pcor = 0.0015). DQ 7
antigen was present in 46.1% of PDH patients compared with 4.9%, 4.4% and 5.3% in
the general population, atopic and non-atopic groups respectively, suggesting
pyrazolone hypersensitivity as a trait positively correlated with this HLA
antigen. CONCLUSION: Our data suggest a genetic predisposition to pyrazolone
hypersensitivity reactions, linked to HLA-DQ locus.
PMID- 9761021
TI - Oilseed rape allergy presented as occupational asthma in the grain industry.
AB - BACKGROUND: There have been several reports on respiratory allergic symptoms
induced by pollen of oilseed rape. To the best of our knowledge, this is the
first report dealing with oilseed rape dust mainly composed of seeds, as an
occupational allergen in the grain industry. In this paper, we present a case of
occupational asthma caused by oilseed rape dust from the Animal Feed Industry,
which proved to be induced by an IgE-mediated reaction. METHODS AND RESULTS: The
patient displayed positive responses to Dermatophagoides farinae as well as
oilseed rape dust extract. The bronchoprovocation test showed an early asthmatic
response to oilseed rape dust extract. Serum specific IgE antibody to oilseed
rape antigen was detected by enzyme-linked immunosorbent assay (ELISA). ELISA
inhibition test showed significant inhibitions with addition of oilseed rape
antigen. In order to further identify the allergenic components of extract,
sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and
immunoblot analysis were performed. Fourteen IgE-binding components ranging from
10 to 160kDa were detected within the oilseed rape extract. CONCLUSION: These
results suggest that the inhalation of oilseed rape dust, not pollen, can cause
IgE mediated bronchoconstriction in an exposed worker of the grain industry.
PMID- 9761022
TI - Participation of T lymphocytes in cutaneous allergic reactions to drugs.
AB - Immunological mechanisms implicated in drug allergic reactions are not yet well
understood, but there is 'in vivo' and 'in vitro' evidence that T lymphocytes are
involved in these hypersensitivity reactions. The cutaneous lymphocyte-associated
antigen (CLA) is the skin homing receptor and is involved in targeting a skin
selective memory T lymphocyte to cutaneous sites of chronic inflammation. We have
seen that CLA expression is increased in circulating T lymphocytes of patients
who develop a drug allergic cutaneous reaction, these cells are activated and
their CLA values tend to become normal in parallel with the disappearance of skin
symptoms, demonstrating that CD3+ CLA+ cells are involved in the immunological
mechanisms responsible for the pathogenesis of the chronic inflammation process
in cutaneous drug reactions.
PMID- 9761023
TI - Presentation of non-peptide antigens, in particular drugs, to specific T cells.
AB - Drugs are non-peptide antigens that can be recognized by specific T cells. It has
been thought for many years that small molecular compounds can only be
stimulating for T cells after covalent binding to MHC-embedded peptides. As most
drug-specific T cell clones can react to glutaraldehyde fixed antigen presenting
cells (APC), recognition of drugs by specific T cells does not require prior
uptake and processing of haptenated proteins by APC. In fact, activated T cell
clones can recognize drugs associated with the MHC-peptide complex in a non
covalent way. Such a binding is reminiscent of superantigen stimulations of T
cells.
PMID- 9761024
TI - Allergic hepatitis: a drug-mediated organ-specific immune reaction.
AB - Idiosyncratic toxicity (i.e. adverse reactions to drugs that occur only in
certain individuals) is a major concern in drug toxicity and drug development.
This type of adverse reaction may appear during the clinical use of a drug,
cannot easily be explained in terms of an exaggerated pharmacological side-effect
of the compound, and is very difficult to anticipate from the preclinical
studies. Hepatic idiosyncratic reactions fall within two categories: those that
are the consequence of an unusual metabolism of the drug (metabolic idiosyncrasy)
and those resulting from an immune-mediated cell injury to hepatocytes which have
been in contact with the drug previously (allergic hepatitis). In the former
case, the toxicity is dose-dependent, while in the latter, toxicity may appear
after several asymptomatic administrations of the compound (sensitization
period). The mechanisms that trigger the immune response have not yet been
precisely defined. Current understanding of how drug allergy arises is based
largely on the hapten hypothesis. Most drugs are not chemically reactive but can
be activated metabolically to reactive species which, after binding to cellular
macromolecules, become immunogenic and can elicit an effective immune response.
Presentation of drug-protein adducts by professional cells to TH lymphocytes,
and/or a direct association between the drug and MHC proteins of hepatocytes
could be involved in the activation of the immune system. As a consequence of
this, drug-directed antibodies and/or T-lymphocytes able to recognize drug
derived haptens arise which are responsible for the clinical manifestations of
the hepatitis. Drug-directed antibodies can be detected in sera of allergic
patients by solid-phase immunoassays. Sensitized T-lymphocytes can be shown by
hapten-induced cell proliferation experiments and by the early expression of CD69
antigen.
PMID- 9761025
TI - Metabolites and allergic drug reactions.
PMID- 9761026
TI - New aspects in betalactam recognition.
AB - The data presented in this review confirm that penicillin continues to be the
most well defined model for studying drug allergy. The identification of new
specificities has improved the understanding of allergy to penicillins, and
different well defined subgroups now exist. The capacity of humans to respond to
unique penicillin determinants has shown that although penicillin is a very small
molecule it can be recognized in different ways by different IgE antibodies.
These well defined models have left open the possibility that other betalactams
can also induce specific reactions which implies that for diagnostic purposes, in
addition to classical determinants, others are required for in vitro and/or in
vivo evaluation. When the different subgroups now recognized are compared, not
only are there differences in the manner of hapten recognition but also in the
evolution of the natural sensitivity and in the capacity for recognizing other
structures. The recognition of betalactams by T cells is also important and a
number of studies have shown that subjects respond specifically to some
aminopenicillins or cephalosporins with good tolerance to benzylpenicillin. The
confirmation that these responses can be a T-cell-mediated reaction have been
reported not only in vitro by the generation of T cell lines and T cell clones
but also in vivo doing skin biopsies in subjects who have developed different
types of delayed cutaneous reactions [44]. More studies are needed to determine
the structure of T cell epitopes and this will help for a better understanding of
both the IgE and IgG-mediated reactions.
PMID- 9761027
TI - Delayed hypersensitivity to aminopenicillins.
PMID- 9761028
TI - T-cell response in penicillin allergy.
AB - Drugs, such as antibiotics, become immunogenic only upon binding to proteins.
Among beta-lactams, penicillins constitute a typical example of allergy inducing
drugs in humans. Previous work on their immunological properties focused mainly
on the examination of IgE-mediated hypersensitivity reactions. However, drug
specific T-cell reactions are also involved in causing a serious allergic
inflammatory response. The experimental data on the reactivity of T cells with
penicillin G point to penicilloyl-modified, MHC-associated peptides as T-cell
epitopes. The recognition specificity of the respective T-cell receptors appears
to be directed at both, the backbone and the specific side-chain of penicillin.
In contrast, the sequence of the carrier peptides contribute as holder for the
haptenic determinant.
PMID- 9761029
TI - Beta-lactam crossreactivity.
PMID- 9761030
TI - Mechanisms implicated in adverse reactions to non-steroidal anti-inflammatory
drugs.
PMID- 9761031
TI - Severe delayed adverse reactions to non-steroidal anti-inflammatory drugs
(NSAIDs).
PMID- 9761032
TI - NSAIDS intolerance: clinical and diagnostic aspects.
PMID- 9761033
TI - New trends in aspirin sensitivity.
PMID- 9761034
TI - Hypersensitivity reactions to drugs in HIV-infected patients. Allergic evaluation
and desensitization.
PMID- 9761035
TI - General and epidemiological aspects of allergic drug reactions.
PMID- 9761036
TI - Acute drug desensitization.
AB - Evidence is accumulating that supports a role for acute desensitization for IgE
mediated drug allergy in those patients for whom no alternative drug exists.
While most of the studies have been performed in penicillin-allergic patients,
this procedure has been used safely in patients with IgE sensitivity to other
agents. In addition, it has been shown that modified desensitization protocols
may be effective in the prevention of other immune-mediated drug reactions, as
well. Thus, while much research remains to be done in this area, drug
desensitization will continue to be a powerful tool in the management of drug
allergy.
PMID- 9761037
TI - Diagnosis and pathogenesis of the anaphylactic and anaphylactoid reactions to
anaesthetics.
AB - Immediate adverse reactions to anaesthetics have an immune mechanism in more than
50% of the cases. They are mainly due to muscle relaxant drugs. A prospective
evaluation of tryptase, histamine and serotonin for diagnosing anaphylaxis to
anaesthetics was performed over 2 years. The sensitivity of each marker was at 60
70% and it reached 80% when combining tryptase and histamine. Specific IgE have
been already observed in serum from patients allergic to muscle relaxant,
thiopentone, morphine, phenoperidine, propofol and radio-contrast media. However,
the recent progress in the identification of drug epitopes by Sepharose-solid
drug phase IgE radioimmunoassay has to be reconsidered as non-specific binding of
hydrophobic drugs such as propofol to hydrophobic serum IgE has been observed
recently in patients with drug allergy. In addition, association of drugs such as
propofol and muscle relaxant may potentiate the mediator release by a non
elucidated mechanism.
PMID- 9761038
TI - Immunological investigation in hepatic drug reactions.
PMID- 9761039
TI - Protein haptenation by drugs.
PMID- 9761040
TI - 'In vivo' models of hapten generation.
PMID- 9761041
TI - The connection between basic research and clinical practice.
PMID- 9761042
TI - Factors affecting excitatory amino acid release following severe human head
injury.
AB - OBJECT: Recent animal studies demonstrate that excitatory amino acids (EAAs) play
a major role in neuronal damage after brain trauma and ischemia. However, the
role of EAAs in patients who have suffered severe head injury is not understood.
Excess quantities of glutamate in the extracellular space may lead to
uncontrolled shifts of sodium, potassium, and calcium, disrupting ionic
homeostasis, which may lead to severe cell swelling and cell death. The authors
evaluated the role of EEAs in human traumatic brain injury. METHODS: In 80
consecutive severely head injured patients, a microdialysis probe was placed into
the gray matter along with a ventriculostomy catheter or an intracranial pressure
(ICP) monitor for 4 days. Levels of EAAs and structural amino acids were analyzed
using high-performance liquid chromatography. Multifactorial analysis of the
amino acid pattern was performed and its correlations with clinical parameters
and outcome were tested. The levels of EAAs were increased up to 50 times normal
in 30% of the patients and were significantly correlated to levels of structural
amino acids both in each patient and across the whole group (p < 0.01). Secondary
ischemic brain injury and focal contusions were most strongly associated with
high EAA levels (27+/-22 micromol/L). Sustained high ICP and poor outcome were
significantly correlated to high levels of EAAs (glutamate > 20 micromol/L; p <
0.01). CONCLUSIONS: The release of EAAs is closely linked to the release of
structural amino acids and may thus reflect nonspecific development of membrane
micropores, rather than presynaptic neuronal vesicular exocytosis. The magnitude
of EAA release in patients with focal contusions and ischemic events may be
sufficient to exacerbate neuronal damage, and these patients may be the best
candidates for treatment with glutamate antagonists in the future.
PMID- 9761043
TI - A multicenter trial on the efficacy of using tirilazad mesylate in cases of head
injury.
AB - OBJECT: The authors prospectively studied the efficacy of tirilazad mesylate, a
novel aminosteroid, in humans with head injuries. METHODS: A cohort of 1120 head
injured patients received at least one dose of study medication (tirilazad or
placebo). Eighty-five percent (957) of the patients had suffered a severe head
injury (Glasgow Coma Scale [GCS] score 4-8) and 15% (163) had sustained a
moderate head injury (GCS score 9-12). Six-month outcomes for the tirilazad- and
placebo-treated groups for the Glasgow Outcome Scale categories of both good
recovery and death showed no significant difference (good recovery in the
tirilazad-treated group was 39% compared with the placebo group in which it was
42% [p=0.461]; death in the tirilazad-treated group occurred in 26% of patients
compared with the placebo group, in which it occurred in 25% [p=0.750]). Subgroup
analysis suggested that tirilazad mesylate may be effective in reducing mortality
rates in males suffering from severe head injury with accompanying traumatic
subarachnoid hemorrhage (death in the tirilazad-treated group occurred in 34% of
patients; in the placebo group it occurred in 43% [p=0.026]). No significant
differences in frequency or types of serious adverse events were shown between
the treatment and placebo groups. CONCLUSIONS: Striking problems with imbalance
concerning basic prognostic variables were observed in spite of the large
population studied. These imbalances concerned pretreatment hypotension,
pretreatment hypoxia, and the incidence of epidural hematomas. In future trials
of pharmacological therapy for severe head injury, serious consideration must be
given to alternative randomization strategies. Given the heterogeneous nature of
head injury and the identification of populations that do relatively well with
standard therapy, target populations with a higher risk for mortality and
morbidity may be more suitable for clinical trials of such agents.
PMID- 9761044
TI - Early changes in middle cerebral artery blood flow velocity after head injury.
AB - OBJECT: This study was designed to investigate the incidence of early
abnormalities in the cerebral circulation after head injury by relating the
results of the initial computerized tomography (CT) scan with transcranial
Doppler (TCD) ultrasound readings to see if the side of injury and the outcome
can be predicted by using these modalities. METHODS: Transcranial Doppler
ultrasound measurements were obtained in the emergency room in 22 head-injured
patients less than 3 hours after injury. The middle cerebral artery (MCA) was
insonated using a standard technique. The TCD measurements in each MCA were
examined individually; of 39 measurements, 22 (56%) showed a low mean blood flow
velocity, 27 (69%) demonstrated a high pulsatility index (PI), and 18 (46%)
showed both abnormalities. The side of the cerebrovascular abnormality measured
by TCD ultrasound did not appear to be an accurate predictor of the side of the
injury as determined on the initial CT scan. Of 13 patients in whom either a
space-occupying hematoma or signs of swelling were shown on the initial CT scan,
10 (77%) had an increased PI in one or both MCAs, which is an indication of high
flow resistance. CONCLUSIONS: Transcranial Doppler ultrasound examinations
performed while patients are in the emergency room may have a role in determining
treatment priorities, especially in those with multiple injuries.
PMID- 9761045
TI - Cerebral monitoring by means of oximetry and somatosensory evoked potentials
during carotid endarterectomy.
AB - OBJECT: Cerebral ischemia that occurs during carotid endarterectomy is commonly
monitored by means of somatosensory evoked potentials (SSEPs) and
electroencephalography (EEG). The authors conducted this study to determine
whether cerebral ischemia could also be reliably detected by cerebral oximetry.
METHODS: Twenty-nine patients who underwent carotid endarterectomy were monitored
by means of SSEPs, EEG, and cerebral oximetry with a model NIRO500 (20 patients)
or INVOS3100A (nine patients) oximeter. Changes in amplitude of SSEPs were graded
as follows: 0, no change; 1, decrease of less than 50%; 2, decrease of greater
than 50%; and 3, 100% decrease. As measured with the NIRO500 oximeter, closing
the common caro-tid artery decreased mean oxyhemoglobin levels twice as much (p <
0.005) in the group with SSEPs of 1 to 3 (-13.11+/-5.59 microM [mean+/-standard
deviation], 12 patients) as in the group with SSEPs of 0 (-6.22+/-5.59 microM,
eight patients). The rise in deoxyhemoglobin was also greater (p < 0.05). Two of
nine patients monitored with the INVOS3100A oximeter had SSEPs of 1 and 3, and
their regional saturation of oxygen (rSO2) values fell by -11.50 and -11.51,
respectively. In the remaining seven patients with SSEPs of 0, the rSO2 ranged
between -2.00 and -6.10 with no overlap with the group with SSEPs of I to 3. The
increase in oxyhemoglobin monitored using the NIRO500 oximeter and rSO2 monitored
using the INVOS3100A machine after opening the external carotid artery was less
than that seen after opening the internal carotid artery. Both types of oximeters
could detect cerebral ischemia but whereas false negatives occurred with the
NIRO500, none was observed with the INVOS3100A. Extracranial contamination was
also four times less frequent with the INVOS3100A than with the NIRO500 monitor.
CONCLUSIONS: The results indicate that at least as measured with the INVOS3100A
instrument, a decrease in rSO2 of -10 or more or a decrease below an rSO2 of 50
is indicative of cerebral ischemia of sufficient severity to decrease the
amplitude of SSEPs.
PMID- 9761046
TI - Arterial aneurysms associated with cerebral arteriovenous malformations:
classification, incidence, and risk of hemorrhage.
AB - OBJECT: The goal of this study was to develop a classification system for
aneurysms associated with arteriovenous malformations (AVMs) based on their
anatomical and pathophysiological relationships and to determine the incidence
and bleeding rates for these aneurysms as well as the effects of AVM treatment on
their natural history. METHODS: Of 632 patients with AVMs, intranidal aneurysms
were found in 35 (5.5%) and flow-related aneurysms in 71 (11.2%). Patients with
intranidal aneurysms presented more frequently with hemorrhage (72% compared with
40%, p < 0.001) and had a 9.8% per year risk rate of bleeding during follow-up
review. Twelve (17%) of the patients with flow-related aneurysms associated with
an AVM presented with hemorrhage from an aneurysm, whereas 15 (21%) bled from
their AVM. Seventeen patients underwent angiography after AVM treatment (mean
2.25 years). Of 23 proximal aneurysms, 18 (78.3%) were unchanged, four (17.4%)
were smaller, and one (4.3%) had disappeared, whereas four (80%) of five distal
aneurysms regressed completely and one was unchanged. Sixteen patients underwent
angiography after partial AVM treatment (mean 3.8 years). In cases with less than
a 50% reduction in the AVM, no aneurysms regressed, although two enlarged and
bled. In cases with greater than a 50% reduction in the AVM, two of three distal
aneurysms disappeared and five proximal aneurysms were unchanged. CONCLUSIONS:
Arterial aneurysms associated with cerebral AVMs may be classified as intranidal,
flow-related, or unrelated to the AVM nidus. Intranidal aneurysms have a high
correlation with hemorrhagic clinical presentation and a risk of bleeding during
the follow-up period that considerably exceeds that which would be expected in
their absence. Patients with flow-related aneurysms in association with an AVM
may present with hemorrhage from either lesion. Aneurysms that arise on distal
feeding arteries near the nidus have a high probability of regressing with
substantial or curative AVM therapy.
PMID- 9761047
TI - The descriptive epidemiology of craniopharyngioma.
AB - OBJECT: In this report the authors describe the epidemiology of
craniopharyngioma. METHODS: The incidence of craniopharyngioma in the United
States was estimated from two population-based cancer registries that include
brain tumors of benign and borderline malignancy: the Central Brain Tumor
Registry of the United States (CBTRUS) and the Los Angeles county Cancer
Surveillance Program. Information on additional pediatric tumors was available
from the Greater Delaware Valley Pediatric Tumor Registry (GDVPTR). The overall
incidence of craniopharyngioma was 0.13 per 100,000 person years and did not vary
by gender or race. A bimodal distribution by age was noted with peak incidence
rates in children (aged 5-14 years) and among older adults (aged 65-74 years in
CBTRUS and 50-74 years in Los Angeles county). Survival information was available
from GDVPTR and the National Cancer Data Base (NCDB), a hospital-based reporting
system. In the NCDB, the 5-year survival rate was 80% and decreased with older
age at diagnosis. Survival is higher among children and has improved in recent
years. CONCLUSIONS: Craniopharyngioma is a rare brain tumor of uncertain behavior
that occurs at a rate of 1.3 per million person years. Approximately 338 cases of
this disease are expected to occur annually in the United States, with 96
occurring in children from 0 to 14 years of age.
PMID- 9761048
TI - Metastatic brain tumors with dural extension.
AB - OBJECT: Twenty-two patients who had solitary metastatic brain tumors with dural
extension were treated surgically over a 3-year period. Their cases were reviewed
to characterize these lesions and to compare the patients with a similar cohort
in which there was no dural involvement. METHODS: The median age of the patients
was 58 years (range 11-68 years) and the male/female ratio was 12:10. The median
preoperative Karnofsky Performance Scale (KPS) score in the group was 90 (range
70-100). The most common histological diagnoses seen in these patients included
breast cancer, adenocarcinoma and squamous cell carcinoma of the lung, and renal
cell carcinoma. All patients underwent gross-total resection of the tumor and 86%
received radiation therapy. The median patient survival time was 11 months, with
a median time to recurrent intracranial disease of 19 months. Survival was
related to the histological diagnosis. Recurrent disease occurred in 41% of
cases. Leptomeningeal disease occurred in three patients (14%). The frequency and
time course of development of recurrent disease was not affected by dural
resection nor was survival. These results for patients having metastatic brain
tumors with dural extension were compared with those for a cohort of 26 patients
in which there were similar histological diagnosis, age, gender, and preoperative
KPS score were distributed similarly but in which each patient had a single
subcortical metastatic lesion. Those patients had a median survival of 10 months
and the median time to recurrence was not reached. Leptomeningeal disease
occurred in one patient (4%). CONCLUSIONS: To the authors' knowledge, this is the
first reported series of patients with metastatic brain tumors with dural
extension. Patients with this disease may be more likely to develop recurrences
along the dura and leptomeningeal disease, but the overall survival time in these
patients is not different from those patients with intraparenchymal lesions.
PMID- 9761049
TI - Detection of soluble E-selectin, ICAM-1, VCAM-1, and L-selectin in the
cerebrospinal fluid of patients after subarachnoid hemorrhage.
AB - OBJECT: The goal of this study was to explore whether the levels of soluble
adhesion molecules were elevated in cerebrospinal fluid (CSF) after subarachnoid
hemorrhage (SAH). This association was suggested by the known inflammatory
response in vasospasm and the role of vascular adhesion molecules in regulating
leukocytic adhesion to, and migration across, vascular endothelium. METHODS: A
prospective analysis was performed on CSF samples obtained in 17 patients who had
suffered a recent aneurysmal SAH and in 16 control patients by using quantitative
enzyme-linked immunosorbent assays for E-selectin, intercellular adhesion
molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and L-selectin.
Levels of soluble forms of E-selectin (p=0.0013), ICAM-1 (p=0.0001), and VCAM-1
(p=0.048) were found to be elevated in the CSF of patients after SAH compared
with levels in the CSF of norminal controls, patients with unruptured aneurysms,
and patients tested months after SAH occurred. In addition, individual patients
tested at the time of their initial ictus demonstrated a fall in adhesion
molecule levels over time. Levels of E-selectin (p=0.044) were highest in
patients who later developed moderate or severe vasospasm. CONCLUSIONS: Adhesion
molecules are known to be involved in white cell adherence to the endothelium and
subsequent diapedesis and migration in which a role in initiation of tissue
damage is postulated. The authors have demonstrated the elevation of three
adhesion molecules, with severely elevated levels of E-selectin seen in patients
who later develop vasospasm. A correlation with a role of vascular adhesion
molecules in the pathogenesis of cerebral vasospasm is suggested.
PMID- 9761050
TI - Changing central nervous system control following intercostal nerve transfer.
AB - OBJECT: The goal of this study was to find which central nervous system (CNS)
pathways are involved in volitional control over reinnervated biceps or pectoral
muscles. METHODS: Intercostal nerves (ICNs) were coapted to the musculocutaneous
nerve (MCN) or the medial pectoral nerve (MPN) in 23 patients with root avulsions
of the brachial plexus to restore biceps or pectoral muscle function. The
facilitatory effects of respiration and voluntary contraction on cortical motor
evoked potentials of biceps or pectoral muscles were used to study CNS control
over the reinnervated muscles. The time course of the facilitatory effect of
respiration and voluntary contraction differed significantly. In the end stage of
nerve regeneration, the facilitatory effect of voluntary contraction was
significantly larger than that of respiration, indicating that the CNS control
network over the muscle comes to resemble that of the recipient nerve (MCN or
MPN) rather than that of the donor nerve (ICN). CONCLUSIONS: The strengthening of
previously subthreshold synaptic connections in a CNS network connecting ICN to
MCN or MPN neurons may underlie changing excitability.
PMID- 9761051
TI - Occlusion of the sigmoid sinus after surgery via the presigmoidal-transpetrosal
approach.
AB - OBJECT: In this paper the authors report on sigmoid sinus occlusion as a surgical
complication in seven of 143 operations in which a presigmoidal-transpetrosal
approach was used. METHODS: Five patients (Cases 1-5) developed occlusion within
40 days after surgery, and in the remaining two (Cases 6 and 7) occlusion was
detected 5.4 and 6.4 years postsurgery by means of cerebral venography, which was
performed in 40 of the remaining 138 patients. Of the two patients with occlusion
of the hypoplastic transverse sinus, one (Case 1) did not develop symptoms and
the other (Case 2) developed brain edema with transient aphasia. Of the three
patients suffering from occlusion of the dominant sigmoid sinus, one (Case 3)
developed severe intracerebral hemorrhages and had a poor prognosis; one (Case 4)
developed profuse supra- and infratentorial brain edema with consciousness
disturbance; and the other (Case 5) developed hemorrhagic infarction in the
temporal lobe accompanied by aphasia. Two patients whose sinus occlusion was
detected later (Cases 6 and 7) did not develop symptoms and displayed well
communicated transverse sinuses. In Case 7, a dural arteriovenous malformation
formed at the site of the sinus occlusion. Laceration of the sigmoid sinus was
suspected as the cause of occlusion in Cases 2, 3, and 7; compression of the
sinus in Cases 5 and 6, sinus laceration and postoperative dehydration in Case 4;
and laceration and compression of the sinus in Case 1. CONCLUSIONS: Differences
in the clinical course among these patients were attributed to anatomical
variations in the venous system. Occlusion of the sigmoid sinus should be weighed
as a potential complication when selecting candidates for the presigmoidal
transpetrosal approach.
PMID- 9761052
TI - Poststroke pain control by chronic motor cortex stimulation: neurological
characteristics predicting a favorable response.
AB - OBJECT: The goal of this study was to identify the neurological characteristics
of patients with poststroke pain who show a favorable response to motor cortex
(MC) stimulation used to control their pain. METHODS: The neurological
characteristics of 31 patients treated by MC stimulation were analyzed. In 15
patients (48%), excellent or good pain control (pain reduction > 60%) was
achieved for follow-up periods of more than 2 years by using MC stimulation at
intensities below the threshold for muscle contraction. Satisfactory pain control
was achieved in 13 (73%) of 18 patients in whom motor weakness in the painful
area was virtually absent or mild, but in only two (15%) of the 13 patients who
demonstrated moderate or severe weakness in the painful area (p < 0.01). Muscle
contraction was inducible in the painful area in 20 patients when stimulated at a
higher intensity. No such muscle response was inducible in the remaining 11
patients, no matter how extensively the authors attempted to determine
appropriate stimulation sites. Satisfactory pain control was achieved in 14 (70%)
of the 20 patients in whom muscle contraction was inducible, but in only one (9%)
of the 11 patients in whom muscle contraction was not inducible (p < 0.01). No
significant relationship was observed between pain control and various sensory
symptoms, including the presence of hypesthesia, spontaneous dysesthesia,
hyperpathia, and allodynia, or the disappearance of the N20 component of the
median nerve-evoked somatosensory scalp potential. No significant relationship
existed between the effect of MC stimulation on the pain and stimulation-induced
phenomena, including paresthesia, improvement in motor performance, and
attenuation of involuntary movements. CONCLUSION: These findings suggest that the
pain control afforded by MC stimulation requires neuronal circuits that are
maintained by the presence of intact corticospinal tract neurons originating from
the MC. Preoperative evaluation of motor weakness of the painful area appears to
be useful for predicting a favorable response to MC stimulation in the control of
poststroke pain.
PMID- 9761053
TI - Fatal cyst formation after fetal mesencephalic allograft transplant for
Parkinson's disease.
AB - OBJECT: In recent years, fetal mesencephalic tissue transplant for the treatment
of Parkinson's disease (PD) has been demonstrated to hold promise, but potential
complications related to growth of allograft tissue have not been well described.
This report explores the development and possible causation of a fatal cyst
arising from a fetal transplant in the brain. METHODS: The authors report the
case of a 52-year-old woman who underwent bilateral putamenal fetal mesencephalic
allograft transplant for PD at another hospital. Twenty-three months later she
presented to the authors' institution in a coma. Admission computerized
tomography and magnetic resonance (MR) studies revealed a contrast-enhancing
mural nodule and associated large cyst arising from the left putamen and causing
brainstem compression. Despite surgical decompression of the cyst, the patient
did not regain consciousness. Biopsy and autopsy specimens were obtained, along
with an analysis of the cyst fluid. Genotyping of the nodule and the patient's
peripheral lymphocytes by using polymerase chain reaction-based microsatellite
analysis was also performed. Biopsy samples and autopsy histopathological studies
showed inflammatory cells, hemosiderin-laden macrophages, and astrocytosis.
Scattered neurons and multiple rests of choroid plexus were also noted. The cyst
had a thin wall and contained liquid that was identical in composition to
cerebrospinal fluid (CSF). Genotyping demonstrated the presence of alleles in the
nodule DNA that were not present in lymphocytic DNA, indicating that the nodule
contained allograft tissue. CONCLUSIONS: The authors hypothesize that the choroid
plexus tissue contained in the allograft resulted in CSF production and cyst
formation at the transplant site, ultimately leading to the patient's herniation
syndrome. The clinical history and large size of the mural nodule indicate slow
growth of this allograft site and cyst over time. This case demonstrates that
unusual patterns of tissue growth can occur in the brain after fetal tissue
transplant and emphasizes the need for long-term monitoring of posttransplant
patients by means of MR imaging. Cell sorting should be considered to ensure
transplant of pure neuronal and astroglial populations.
PMID- 9761054
TI - Transthoracic vertebrectomy for metastatic spinal tumors.
AB - OBJECT: Anterior approaches to the spine for the treatment of spinal tumors have
gained acceptance; however, in most published reports, patients with primary,
metastatic, or chest wall tumors involving cervical, thoracic, or lumbar regions
of the spine are combined. The purpose of this study was to provide a clear
perspective of results that can be expected in patients who undergo anterior
vertebral body resection, reconstruction, and stabilization for spinal metastases
that are limited to the thoracic region. METHODS: Outcome is presented for 72
patients with metastatic spinal tumors who were treated by transthoracic
vertebrectomy at The University of Texas M. D. Anderson Cancer Center. The
predominant primary tumors included renal cancer in 19 patients, breast cancer in
10, melanoma or sarcoma in 10, and lung cancer in nine patients. The most common
presenting symptoms were back pain, which occurred in 90% of patients, and lower
extremity weakness, which occurred in 64% of patients. All patients underwent
transthoracic vertebrectomy, decompression, reconstruction with
methylmethacrylate, and anterior fixation with locking plate and screw
constructs. Supplemental posterior instrumentation was required in seven patients
with disease involving the cervicothoracic or thoracolumbar junction, which was
causing severe kyphosis. After surgery, pain improved in 60 of 65 patients. This
improvement was found to be statistically significant (p < 0.001) based on visual
analog scales and narcotic analgesic medication use. Thirty-five of the 46
patients who presented with neurological dysfunction improved significantly (p <
0.001) following the procedure. Thirty-three patients had weakness but could
ambulate preoperatively. Seventeen of these 33 regained normal strength, 15
patients continued to have weakness, and one patient was neurologically worse
postoperatively. Of the 13 preoperatively nonambulatory patients, 10 could walk
after surgery and three were still unable to walk but showed improved motor
function. Twenty-one patients had complications ranging from minor atelectasis to
pulmonary embolism. The 30-day mortality rate was 3%. The 1-year survival rate
for the entire study population was 62%. CONCLUSIONS: These results suggest that
transthoracic vertebrectomy and spinal stabilization can improve the quality of
life considerably in cancer patients with spinal metastasis by restoring or
preserving ambulation and by controlling intractable spinal pain with acceptable
rates of morbidity and mortality.
PMID- 9761055
TI - Direct convective delivery of macromolecules to peripheral nerves.
AB - OBJECT: Although many macromolecules have treatment potential for peripheral
nerve disease, clinical use of these agents has been restricted because of
limitations of delivery including systemic toxicity, heterogeneous dispersion,
and inadequate distribution. In an effort to overcome these obstacles, the
authors examined the use of convection to deliver and distribute macromolecules
into peripheral nerves. METHODS: For convective delivery, the authors used a gas
tight, noncompliant system that provided continuous flow through a small silica
cannula (inner diameter 100 microm, outer diameter 170 microm) inserted into a
peripheral nerve. Increases in the volume of infusion (Vi) (10, 20, 30, 40, and
80 microl) of 14C-labeled (nine nerves) or gadolinium-labeled (two nerves)
albumin were infused unilaterally or bilaterally into the tibial nerves of six
primates (Macaca mulatta) at 0.5 microl/minute. The volume of distribution (Vd),
percentage recovery, and delivery homogeneity were determined using quantitative
autoradiography, an imaging program developed by the National Institutes of
Health, magnetic resonance (MR) imaging, scintillation counting, and kurtosis (K)
analysis. One animal that was infused bilaterally with gadolinium-bound albumin
(40 microl to each nerve) underwent MR imaging and was observed for 16 weeks
after infusion. The Vd increased with the Vi in a logarithmic fashion. The mean
Vd/Vi ratio over all Vi was 3.7+/-0.8 (mean+/-standard deviation). The
concentration across the perfused region was homogeneous (K=-1.07). The infusate,
which was limited circumferentially by the epineurium, followed the parallel
arrangement of axonal fibers and filled long segments of nerve (up to 6.8 cm).
Recovery of radioactivity was 75.8+/-9%. No neurological deficits arose from
infusion. CONCLUSIONS: Convective delivery of macromolecules to peripheral nerves
is safe and reliable. It overcomes obstacles associated with current delivery
methods and allows selective regional delivery of putative therapeutic agents to
long sections of nerve. This technique should permit the development of new
treatments for numerous types of peripheral nerve lesions.
PMID- 9761056
TI - Direct convective delivery of macromolecules to the spinal cord.
AB - OBJECT: Because of the limited penetration of macromolecules across the blood
spinal cord barrier, numerous therapeutic compounds with potential for treating
spinal cord disorders cannot be used effectively. The authors have developed a
technique to deliver and distribute macromolecules regionally in the spinal cord
by using convection in the interstitial space. METHODS: The authors designed a
delivery system connected to a "floating" silica cannula (inner diameter 100
microm, outer diameter 170 microm) that provides for constant volumetric inflow
to the spinal cord. A solution containing albumin that was either unlabeled or
labeled with carbon-14 or gadolinium was infused at various volumes (3, 6, 10,
20, 40, or 50 microl) at a rate of 0.1 microl/minute into the spinal cord dorsal
columns of nine swine and into the lateral columns of three primates (Macaca
mulatta). Volume of distribution (Vd), concentration homogeneity, and percentage
of recovery were determined using scintillation analysis, kurtosis calculation
(K), and quantitative autoradiography (six swine), magnetic resonance imaging
(one swine and three primates), and histological analysis (all animals).
Neurological function was observed for up to 3 days in four of the swine and up
to 16 weeks in the three primates. The Vd of 14C-albumin was linearly
proportional (R2=0.97) to the volume of infusion (Vi) (Vd/Vi=4.4+/-0.5; [mean+/
standard deviation). The increases in Vd resulting from increases in Vi were
primarily in the longitudinal dimension (R2=0.83 in swine; R2=0.98 in primates),
allowing large segments of spinal cord (up to 4.3 cm; Vi 50 microl) to be
perfused with the macromolecule. The concentration across the area of
distribution was homogeneous (K=-1.1). The mean recovery of infused albumin from
the spinal cord was 85.5+/-5.6%. Magnetic resonance imaging and histological
analysis combined with quantitative autoradiography revealed the albumin infusate
to be preferentially distributed along the white matter tracts. No animal
exhibited a neurological deficit as a result of the infusion. CONCLUSIONS:
Regional convective delivery provides reproducible, safe, region-specific, and
homogeneous distribution of macromolecules over large longitudinal segments of
the spinal cord. This delivery method overcomes many of the obstacles associated
with current delivery techniques and provides for research into new treatments of
various conditions of the spinal cord.
PMID- 9761057
TI - Role of transforming growth factor-beta1 in the pathogenesis of moyamoya disease.
AB - OBJECT: Prominent features of moyamoya disease are intimal thickening of the
cerebral arterial trunks and abundant angiogenesis for collateral blood supplies,
but its pathogenesis is still unknown. The aim of this study was to test the
possibility that transforming growth factor-beta1 (TGFbeta1) may play a role in
the pathogenesis of moyamoya disease. METHODS: The authors used reverse
transcription-polymerase chain reaction to analyze the expression level of
TGFbeta1 in smooth-muscle cells cultured from the superficial temporal arteries
(STAs) and measured the serum level of TGFbeta1 by using enzyme-linked
immunosorbent assay. Although the STA is not predominantly involved with moyamoya
disease, it has been used in studies of the pathogenesis of this disease. In this
report, the STAs from six patients with moyamoya disease and four with
arteriosclerotic cerebrovascular disease, along with sera from 14 patients with
moyamoya disease and 10 normal healthy volunteers, were studied. The expression
of TGFbeta1 was significantly higher in cultured smooth-muscle cells derived from
the STAs of patients with moyamoya disease than in those derived from the STAs of
patients with arteriosclerotic cerebrovascular disease (p < 0.05). The serum
level of TGFbeta1 was also significantly higher in patients with moyamoya disease
than in controls (p < 0.0005). CONCLUSIONS: Taking into account the functional
roles of TGFbeta1 in the expression of connective tissue genes and angiogenesis,
these investigators suggest that TGFbeta1 is associated with the pathogenesis of
moyamoya disease, including abundant neovascularization, although their findings
do not necessarily mean that TGFbeta1 is a causative factor in this disease.
PMID- 9761058
TI - The importance of accurate lesion placement in posteroventral pallidotomy. Report
of two cases.
AB - Pallidotomy has become a widely used treatment for medically refractory
Parkinson's disease. However, the optimal lesion size and location within the
pallidum have not yet been determined, and the role of repeated pallidotomy
remains undefined. The authors present two patients who had unsatisfactory
results after their first unilateral pallidotomy but attained dramatic and long
lasting improvement with repeated surgery. The results obtained in these cases
indicate that patients who have a good clinical outcome initially but relapse
rapidly after surgery should be considered for repeated pallidotomy if the
initial lesion was not placed in the optimal location.
PMID- 9761059
TI - Neuroradiological findings in adult cranially conjoined twins. Case report.
AB - The authors demonstrate the radiological anatomy and review the accepted
embryological theories in a case of total craniopagus. These 24-year-old female
cranially conjoined twins were studied with computerized tomography (CT) and CT
angiography, magnetic resonance (MR) imaging and MR angiography as well as
selective arterial digital subtraction (DS) angiography to clarify whether
surgical separation was possible. The neuroradiological findings are discussed,
taking into consideration both the embryological and surgical literature. The
malformation was classified as a total parietooccipitotemporal craniopagus.
Whereas CT angiography and MR imaging including MR angiography demonstrated a
common superior sagittal sinus, only selective arterial DS angiography revealed a
significant arterial and venous cross-flow between the two adjacent temporal
lobes. Selective intraarterial DS angiography is required in the
neuroradiological evaluation of complex malformations, even when the anatomy of
brain and skull can be well demonstrated with high-quality MR and CT studies.
PMID- 9761060
TI - Detection of Bartonella henselae by polymerase chain reaction in brain tissue of
an immunocompromised patient with multiple enhancing lesions. Case report and
review of the literature.
AB - The authors report the first DNA-based diagnosis of Bartonella henselae cultured
from a brain lesion in a patient with acquired immune deficiency syndrome. This
human immunodeficiency virus-infected patient presented with altered mental
status, fever, and diabetes insipidus. Magnetic resonance imaging revealed
multifocal parenchymal and leptomeningeal involvement, which was confirmed on
studies of tissue biopsy samples. Using the polymerase chain reaction and gene
sequencing techniques, the authors definitively demonstrated the presence of B.
henselae in the brain tissue biopsy specimen.
PMID- 9761061
TI - Subsidence of seizure induced by stereotactic radiation in a patient with
hypothalamic hamartoma. Case report.
AB - The authors report on a patient who exhibited intractable epilepsy due to an
inaccessible hypothalamic hamartoma and subsequently underwent stereotactic
radiosurgery. This 25-year-old man had a 24-year history of intractable gelastic
and tonic-clonic seizures. Magnetic resonance (MR) imaging performed at
examination as well as that performed 30 months earlier demonstrated a
nonenhancing and nonprogressive spherical mass, approximately 10 mm in diameter,
located on the patient's right side at the floor of the third ventricle. Focal
radiation treatment performed with a gamma knife unit administered 36 Gy to the
center and 18 Gy to the periphery of the lesion. This treatment resulted in an
improvement in seizure control. Before the patient underwent radiosurgery, he
suffered from three to six generalized seizures per month in spite of attentive
compliance with an anticonvulsant medication regimen. After irradiation of the
harmatoma, the frequency of the seizures transiently increased and then subsided
3 months posttreatment. The patient has been free of seizures for the last 21
months, with no neurological or endocrinological complications. Magnetic
resonance imaging performed 12 months posttreatment demonstrated complete
disappearance of the lesion.
PMID- 9761062
TI - Continuous hemodialysis for the management of acute renal failure in the presence
of cerebellar hemorrhage. Case report.
AB - In this report the authors describe the use of continuous venovenous hemodialysis
(CVVHD) in a medically unstable patient who suffered from a spontaneous
cerebellar hemorrhage. Conventional dialysis techniques carry the risk of
developing the dialysis disequilibrium syndrome (DDS) when performed in the
presence of a variety of intracranial diseases. The CVVHD technique was used
successfully in a morbidly obese, short-statured woman with a spontaneous
hypertensive intraparenchymal cerebellar hemorrhage. The woman experienced acute
renal failure several days after her hemorrhage and her general medical condition
prevented her from undergoing surgical evacuation. The CVVHD did not result in
elevations in intracranial pressure (ICP) and the patient made a full recovery
from both acute renal failure and life-threatening posterior fossa hemorrhage.
This case is noteworthy because of the absence of abnormally high ICP elevations
or development of DDS in a patient with a large acute posterior fossa
intraparenchymal brain hemorrhage and acute renal failure whose case was managed
with CVVHD in the acute period.
PMID- 9761063
TI - Death from a malignant cerebellopontine angle triton tumor despite stereotactic
radiosurgery. Case report.
AB - Malignant vestibular nerve tumors are rare: to date, only three cases have been
reported in the literature. The authors report a case of an eighth cranial nerve
tumor that progressed 5 years after stereotactic radiosurgery. The patient was a
44-year-old man who underwent stereotactic radiosurgery for a 27-mm
cerebellopontine angle tumor that was discovered on investigation of tinnitus and
hearing loss. He developed facial weakness after 5 years, and repeated imaging
revealed tumor enlargement. Despite complete microsurgical excision, the tumor
rapidly recurred locally and subsequently disseminated within the neuraxis. The
patient died 1 year after tumor progression was detected. Histopathological
analysis revealed a malignant spindle cell neoplasm with frequent mitotic
figures. The presence of positive rhabdoid elements on immunohistochemical
studies confirmed that it was a triton tumor. The authors review the relevant
literature concerning the classification and management of malignant vestibular
nerve tumors and discuss the implications of tumor progression after stereotactic
radiosurgery.
PMID- 9761064
TI - Primary cervical melanoma with brain metastases. Case report and review of the
literature.
AB - Primary intramedullary melanoma is a very rare tumor that occurs most frequently
in the middle or lower thoracic spinal cord. The authors present a case of
primary cervical cord melanoma that developed in a 62-year-old man who was
surgically treated and subsequently underwent radiation therapy. Clinical and
histogenetic features of this neoplasm and results of chemo-. radio-, and
immunotherapy are reported. Both "dysembryogenetic" and "mesodermal" hypotheses
on the origin of primary spinal melanoma are discussed.
PMID- 9761065
TI - Cavernous sinus syndrome during balloon test occlusion of the cervical internal
carotid artery. Report of two cases.
AB - The authors report the occurrence of ipsilateral transient cavernous sinus
syndrome during balloon test occlusion (BTO) of the cervical internal carotid
artery (ICA) and discuss the involved pathomechanisms. The authors reviewed their
series of 129 BTOs of the ICA performed between 1989 and 1996. Two patients
developed facial paresthesias and transient palsies of the third through sixth
cranial nerves during test occlusion of the cervical ICA. The tests were
performed prior to planned permanent carotid artery occlusion for the treatment
of a neck sarcoma in one patient and a giant cavernous carotid artery aneurysm in
the other. The patients' symptoms resolved with deflation of the balloon. When
the balloon was subsequently inflated above the inferior cavernous sinus artery
(ICSA), one of the patients complained of mild facial discomfort. There was no
contralateral weakness or mental status change during test occlusion in either
patient. Angiography demonstrated good filling of the ipsilateral intracranial
circulation via collateral vessels of the circle of Willis. In these two cases,
the cranial nerves in the cavernous sinus were likely supplied by the ICA via the
meningohypophyseal trunk and the ICSA. In each case, there was excellent blood
supply to the ipsilateral cerebral hemisphere; however, there was probably
inadequate retrograde filling of the cranial nerve collateral vessels located
where the meningohypophyseal trunk and ICSA originated. These cases emphasize the
importance of a patent external carotid artery-ICA connection for successful
cervical carotid artery occlusion. Neurological examination during BTO was
critical to interpret the clinical manifestations caused by the hemodynamic
changes.
PMID- 9761066
TI - Reconstruction of the vein of Labbe by using a short saphenous vein bypass graft.
Technical note.
AB - Protection of the vein of Labbe is a significant concern during surgery that
involves retraction of the temporal lobe. A cranial base surgical approach,
especially one via the presigmoid-petrosal route, carries considerable risk to
this venous complex. A case is presented in which a large dominant vein of Labbe
was injured during resection of a petroclival meningioma. This vein drained all
the sylvian venous circulation as well as the lateral temporal surface; no
connection to another venous system was noted. The vein was successfully
reconstructed using a short saphenous vein bypass graft. Significant
complications could have occurred without this reconstruction. The technique and
benefits of this type of reconstruction are discussed.
PMID- 9761067
TI - Intracranial vascular anastomosis using the microanastomotic system. Technical
note.
AB - The authors describe the use of a microanastomotic device to perform intracranial
end-to-end vascular anastomoses. Direct end-to-end anastomosis was performed
between the superficial temporal artery and branches of the middle cerebral
artery (MCA) in three patients. Two patients had moyamoya disease, with severe
proximal MCA disease, and one suffered an internal carotid artery occlusion with
poor collateral flow. All patients reported a history of recent ischemic
symptoms. Each anastomosis was accomplished in less than 15 minutes with
technically satisfactory results. Postoperative angiographic studies demonstrated
patency of the bypasses in all patients.
PMID- 9761068
TI - Infection of a Rathke's cleft cyst: a rare cause of pituitary abscess. Case
illustration.
PMID- 9761069
TI - Fibrolipomatous hamartoma of the median nerve. Case illustration.
PMID- 9761070
TI - Omental transplantation.
PMID- 9761071
TI - Chordoid meningioma.
PMID- 9761072
TI - Guidelines or potentially dangerous recommendations? The AANS/CNS Committee on
Assessment of Quality. American Association of Neurological Surgeons. Congress of
Neurological Surgeons.
PMID- 9761073
TI - Radiosurgery and microsurgery for AVMs.
PMID- 9761074
TI - Radiosurgery and microsurgery for AVMs.
PMID- 9761075
TI - Doppler ultrasound in subarachnoid hemorrhage.
PMID- 9761076
TI - Doppler ultrasound in subarachnoid hemorrhage.
PMID- 9761077
TI - Abciximab administration and outcome after intracoronary stent implantation.
AB - Although adjunctive abciximab therapy improves outcome after angioplasty or
atherectomy, there are few data demonstrating its benefit for intracoronary stent
implantation. We characterized patients receiving abciximab for stent placement
in our practice and determined the impact of abciximab on outcome. Abciximab was
introduced to our practice in April 1995 for percutaneous revascularization.
Demographic, clinical, and angiographic variables that were independently
associated with the use of abciximab for stent placement through 1996 (abciximab
era) were examined. We then examined among all patients receiving stents from
1992 through 1996 (preabciximab and abciximab eras) whether the use of abciximab
was independently associated with improved outcome (death, nonfatal Q-wave
myocardial infarction, coronary bypass surgery, or target vessel percutaneous
revascularization) in the hospital and at 30 days. The 30-day event rate was 7%
for those who did or did not receive abciximab. The following characteristics
were independently associated with the use of abciximab for stent placement in
the abciximab era: thrombus before stent placement (chi-square 50.5), > or =2
stents implanted (chi-square 10.8), stent in venous graft (chi-square 7.4),
calcific lesion (chi-square 5.8), and hypertension (chi-square 5.5). Among all
patients receiving stents in the preabciximab and abciximab eras (n=1,859), the
presence of these characteristics was independently associated with worse
outcome. Abciximab, however, did not improve outcome in the hospital (odds ratio
[95% confidence interval]=0.96 [0.58 to 1.58]) or at 30 days (0.87 [0.53 to
1.41]), even after adjusting for these characteristics. Abciximab for stent
placement was used in high-risk patients in our practice but was not associated
with improved outcome.
PMID- 9761078
TI - Comparison of coronary endothelial dynamics with electrocardiographic and left
ventricular contractile responses to stress in the absence of coronary artery
disease.
AB - Coronary artery endothelial dysfunction has been proposed as a cause of
myocardial ischemia and symptoms in patients with angina-like chest pain despite
normal coronary angiograms, especially those with ischemic-appearing ST-segment
depression during exercise (syndrome X). We measured coronary vasomotor responses
to acetylcholine (3 to 300 microg/min) in 42 patients (27 women and 15 men) with
effort chest pain and normal coronary angiograms who also had normal
electrocardiograms and echocardiograms at rest. All patients underwent treadmill
exercise testing and measurement of systolic wall thickening responses to
dobutamine (40 microg/kg/min) during transesophageal echocardiography. There were
no differences in the acetylcholine-stimulated epicardial coronary diameter (+5+/
13% vs +1+/-13%, p=0.386) and flow (+179+/-90% vs +169+/-96%, p=0.756), or in the
systolic wall thickening responses (+134+/-65% vs +118+/-57%, p=0.445) from
baseline values in the 12 syndrome X patients compared with the 30 patients with
negative exercise test results. In patients in the lowest quartile of coronary
flow responses to acetylcholine, dobutamine increased systolic wall thickening by
121+/-73%; 3 had ischemic-appearing ST-segment depression during this stress.
This contractile response to dobutamine was no different than the increase in
systolic wall thickening (129+/-48%, p=0.777) in patients in the highest quartile
of coronary flow responses, 3 of whom also had ischemic-appearing ST-segment
depression during this stress. Thus, coronary endothelial dysfunction in the
absence of coronary artery disease does not account for ischemic-appearing ST
segment depression in patients with chest pain despite normal coronary
angiograms. Further, coronary endothelial dysfunction is not associated with
myocardial contractile responses to stress consistent with myocardial ischemia.
PMID- 9761079
TI - Incremental prognostic value of serum levels of troponin T and C-reactive protein
on admission in patients with unstable angina pectoris.
AB - Management of unstable angina is largely determined by symptoms, yet some
symptomatic patients stabilize, whereas others develop myocardial infarction
after waning of symptoms. Therefore, markers of short-term risk, available on
admission, are needed. The value of 4 prognostic indicators available on
admission (pain in the last 24 hours, electrocardiogram [ECG], troponin T, and C
reactive protein [CRP]), and of Holter monitoring available during the subsequent
24 hours was analyzed in 102 patients with Braunwald class IIIB unstable angina
hospitalized in 4 centers. The patients were divided into 3 groups: group 1, 27
with pain during the last 24 hours and ischemic electrocardiographic changes;
group 2, 45 with pain or electrocardiographic changes; group 3, 30 with neither
pain nor electrocardiographic changes. Troponin T, CRP, ECG on admission, and
Holter monitoring were analyzed blindly in the core laboratory. Fifteen patients
developed myocardial infarction: 22% in group 1, 13% in group 2, and 10% in group
3. Twenty-eight patients underwent revascularization: 37% in group 1, 35% in
group 2, and 7% in group 2 (p <0.01 between groups 1 or 2 vs group 3). Myocardial
infarction was more frequent in patients with elevated troponin T (50% vs 9%,
p=0.001) and elevated CRP (24% vs 4%, p= 0.01). Positive troponin T or CRP
identified all myocardial infarctions in group 3. Only 1 of 46 patients with
negative troponin T and CRP developed myocardial infarction. Among the indicators
available on admission, multivariate analysis showed that troponin T (p=0.02) and
CRP (p=0.04) were independently associated with myocardial infarction. Troponin T
had the highest specificity (92%), and CRP the highest sensitivity (87%).
Positive results on Holter monitoring were also associated with myocardial
infarction (p=0.003), but when added to troponin T and CRP, increased specificity
and positive predictive value by only 3%. Thus, in patients with class IIIB
unstable angina, among data potentially available on admission, serum levels of
troponin T and CRP have a significantly greater prognostic accuracy than symptoms
and ECGs. Holter monitoring, available 24 hours later, adds no significant
information.
PMID- 9761080
TI - Risk stratification of patients with medically treated unstable angina using
exercise echocardiography.
AB - Functional testing is recommended for risk stratification of medically treated
patients with unstable angina. Exercise echocardiography is used in this
situation, but its safety and prognostic value are not well defined. The
objective of this study was to assess the incremental prognostic value of
exercise echocardiography in 226 consecutive patients (128 men, age 59+/-13
years) with medically treated unstable angina, who underwent exercise
echocardiography from 1991 to 1996. Clinical risk was designated as low in 108
patients, intermediate in 116, and high in 2 patients according to the unstable
angina practice guidelines. There were no major complications from the stress
tests. The exercise electrocardiogram was nondiagnostic in 57 patients (25%).
Ischemia was identified by exercise electrocardiography in 33 patients and
exercise echocardiography in 55 patients. Patients were followed for 29+/-18
months. After exclusion of 38 patients who underwent early revascularization, 28
patients had cardiac death, nonfatal infarction, and late (>3 months)
revascularization. Ischemia at exercise echocardiography was associated with a 24
month event-free survival of 81%, compared to 95% with negative exercise
echocardiography (p=0.02). A positive exercise electrocardiogram was associated
with a 24-month event-free survival of 84%, compared to 93% with negative
exercise electrocardiograms (p=0.08). In a Cox regression model, event-free
survival was predicted by ischemia at exercise echocardiography (relative risk
2.8, confidence interval: 1.3 to 6.3, p=0.05), but not at exercise
electrocardiography (relative risk 2.1, confidence interval 0.7 to 5.8, p=0.16).
PMID- 9761081
TI - Incremental prognostic value of adenosine myocardial perfusion single-photon
emission computed tomography in women with suspected coronary artery disease.
AB - Adenosine myocardial perfusion single-photon emission computed tomography (SPECT)
is now increasingly used for risk stratification of patients with known or
suspected coronary artery disease. However, the incremental prognostic value of
this test over clinical and historical information in a large series of women has
not been examined. Thus, we studied 923 consecutive women who underwent adenosine
technetium (Tc)-99m sestamibi myocardial perfusion SPECT and were followed-up for
a mean period of 26+/-8 months. During the follow-up period, 77 hard events (46
cardiac deaths and 31 nonfatal myocardial infarctions) occurred. The results of
the perfusion scan significantly risk stratified the population; patients with
normal scans had a low rate of nonfatal myocardial infarction and cardiac death
(< 1%/year of follow up). Patients with mildly abnormal scans had low cardiac
death rates (0.9%/year of follow up); these rates increased as a function of scan
abnormality (4.1% and 7.5% mortality per year of follow up in moderate and
severely abnormal scans). Cox proportional hazards analysis demonstrated that
after adjusting for prior myocardial infarction and diabetes mellitus (the most
predictive individual clinical variables [global chi-square=22.5, p <0.001]), as
well as heart rate at rest (the most predictive physiologic variable [chi
square=3.8; p=0.05]), the most predictive nuclear variable (summed stress score
[chi-square=48.5; p <0.0001]) added significant incremental prognostic
information (global chi-square increased from 22.5 to 56.2 [p <0.0001]). In
conclusion, adenosine myocardial perfusion SPECT added significant incremental
prognostic information to clinical and physiologic variables in women. Normal
scans were associated with an excellent prognosis. In contrast, patients with
moderately to severely abnormal scans were at a higher risk for future cardiac
events.
PMID- 9761082
TI - Invasive versus conservative strategies in unstable angina and non-Q-wave
myocardial infarction following treatment with tirofiban: rationale and study
design of the international TACTICS-TIMI 18 Trial. Treat Angina with Aggrastat
and determine Cost of Therapy with an Invasive or Conservative Strategy.
Thrombolysis In Myocardial Infarction.
AB - In the management of unstable angina and non-Q-wave acute myocardial infarction
(AMI), there is considerable debate regarding the use of invasive strategy versus
conservative strategy. The Thrombolysis In Myocardial Infarction (TIMI) III B
trial found similar clinical outcomes for the 2 strategies, but the Veterans
Administration Non-Q-Wave Infarction Strategies in-Hospital trial found a higher
mortality with the invasive strategy. Both these trials were conducted before
platelet glycoprotein IIb/IIIa inhibition and coronary stenting, both of which
improve clinical outcome. Thus, there is a need to reexamine the question of
which management strategy is optimal in the current era of platelet glycoprotein
IIb/IIIa inhibition and new coronary interventions. The Treat Angina with
Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy
(TACTICS-TIMI 18) trial is an international, multicenter, randomized trial that
is evaluating the clinical efficacy of early invasive and early conservative
treatment strategies in patients with unstable angina or non-Q-wave AMI treated
with tirofiban, heparin, and aspirin. Patients are randomized to an invasive
strategy, involving cardiac catheterization within 4 to 48 hours and
revascularization with angioplasty or bypass surgery if feasible, versus a
conservative strategy, where patients are referred for catheterization only for
recurrent pain at rest or provokable ischemia. The primary end point is death,
MI, or rehospitalization for acute coronary syndromes through a 6-month follow
up. The trial is also testing the "troponin hypothesis," that baseline troponins
T and I will be useful in selecting an optimal management strategy.
PMID- 9761083
TI - Effectiveness of once-nightly dosing of extended-release niacin alone and in
combination for hypercholesterolemia.
AB - We performed a multicenter, open-label study to determine the long-term safety
and efficacy of a new extended-release once-a-night niacin preparation, Niaspan,
in the treatment of hypercholesterolemia. Niaspan, 0.5 to 3.0 g once a night at
bedtime, was used alone or in combination with a statin (inhibitor of
hydroxymethylglutaryl coenzyme A reductase), a bile acid sequestrant, or both.
Patients included 269 hypercholesterolemic male and female adults enrolled in a
96-week study, and 230 additional adults for whom short-term safety data were
available. The dosages of Niaspan attained by 269 patients were 1,000 mg (95% of
patients), 1,500 mg (86%), and 2,000 mg (65%). After 48 weeks of treatment,
Niaspan alone (median dose 2,000 mg) reduced low-density lipaprotein (LDL)
cholesterol (18%), apolipoprotein B (15%), total cholesterol (11%), triglycerides
(24%), and lipoprotein(a) (36%), and increased high-density lipoprotein (HDL)
cholesterol (29%). Niaspan plus a statin lowered LDL cholesterol (32%),
apolipoprotein B (26%), total cholesterol (23%), triglycerides (30%), and
lipoprotein(a) (19%), and increased HDL cholesterol (26%). Reversible elevations
of aspartate aminotransferase or alanine aminotransferase more than twice the
normal range occurred in 2.6% of patients. One patient discontinued Niaspan
because of transaminase elevations. Intolerance to flushing, leading to
discontinuation of Niaspan, occurred in 4.8% of patients. The overall rate of
discontinuance due to flushing in this study combined with 2 previous randomized
trials was 7.3%. In the long-term treatment of hypercholesterolemia, Niaspan
produced favorable changes in LDL and HDL cholesterol, triglycerides, and
lipoprotein(a). Adverse hepatic effects were minor and occurred at rates similar
to those reported for statin therapy.
PMID- 9761084
TI - Comparison of metoprolol and sotalol in preventing ventricular tachyarrhythmias
after the implantation of a cardioverter/defibrillator.
AB - The purpose of this prospective study was to evaluate, on an intention-to-treat
basis, the efficacy of d,l-sotalol and metoprolol with regards to the recurrence
of arrhythmic events after implantable cardioverter defibrillator (ICD)
implantation. After ICD implantation, 70 patients were randomly assigned to
treatment with either metoprolol (mean dosage 104+/-37 mg/day in 35 patients) or
d,l-sotalol (mean dosage 242+/-109 mg/day in 35 patients). During follow up
ventricular tachycardia (VT), fast VT, and ventricular fibrillation (VF) episodes
were calculated. Metoprolol treatment led to a marked reduction in the recurrence
of arrhythmic events. Actuarial rates for absence of VT recurrence at 1 and 2
years were significantly higher in the metoprolol group compared with the d,l
sotalol group (83% and 80% vs 57% and 51%, respectively, p=0.016). The actuarial
rates for absence of fast VT or VF were 80% in the metoprolol group compared with
46% in the d,l-sotalol group (p=0.002). During a follow up of 26+/-16 months,
there were 3 deaths in the metoprolol group compared with 6 deaths in the d,l
sotalol group. Actuarial rates of overall survival were not significantly
different in the 2 groups (91% vs 83%, p=0.287). In this prospective, randomized,
controlled study the recurrence rate of ventricular tachyarrhythmias in patients
treated with metoprolol was lower than in patients treated by d,l-sotolol.
PMID- 9761085
TI - Effects of prostacyclin on the pulmonary vascular tone and cardiac contractility
of patients with pulmonary hypertension secondary to end-stage heart failure.
AB - Long-term administration of prostacyclin (PGI2) improves the hemodynamic state,
symptoms, and survival in patients with primary pulmonary hypertension, but it
increases mortality in patients with heart failure despite obvious hemodynamic
benefits when it is given acutely. We evaluated the mechanisms of action of PGI2
in patients with heart failure and secondary pulmonary hypertension. Nineteen
patients with end-stage heart failure and pulmonary hypertension, all candidates
for heart transplantation, underwent right- and left sided cardiac
catheterization with micromanometer-tipped catheters and were tested for PGI2 at
incremental doses. PGI2 infusion significantly improved pulmonary hemodynamics
with a 47% reduction in pulmonary vascular resistance (p=0.0003) and a doubling
of pulmonary artery compliance (p <0.0001), reflecting improvement in pulmonary
vascular tone. The dose of PGI2 necessary to reach this hemodynamic effect
correlated significantly to the baseline severity of pulmonary artery compliance
(r=0.54, p=0.01). Furthermore, PGI2 produced a significant positive inotropic
effect (contractile element maximum velocity increased from 1.10+/-0.09 to 1.33+/
0.13 circ/s, p <0.009). The hemodynamic effects of PGI2 infusion were independent
of the plasma and urinary levels of endogen prostaglandins. Thus, PGI2 at
therapeutic doses exerts a positive inotropic effect in patients with heart
failure, which may explain the increased mortality rate observed with the long
term use of PGI2 in this type of patient. The spectacular acute benefits on right
ventricular afterload, however, may be useful in unstable patients with heart
failure and secondary pulmonary hypertension or in transplanted patients with
acute right ventricular failure of the donor heart.
PMID- 9761086
TI - Increasing degrees of left ventricular filling impairment modulate left atrial
function in humans.
AB - We sought to investigate the changes in atrial reservoir, pump, and conduit
functions that are associated with increasing degrees of left ventricular filling
impairment. In 13 patients with an impaired relaxation type of filling and in 15
with restrictive patterns, the left atrial volume curve was constructed combining
Doppler and 2-dimensional echocardiography. Nine normal subjects served as
controls. Left atrial reservoir (defined as [maximum - minimum atrial volume]
minus the amount of blood flow reversal in the pulmonary veins with atrial
contraction), pump (defined by the volume of blood that enters the ventricle with
atrial contraction), and conduit functions (defined as left ventricular filling
volume - [left atrial reservoir plus pump volume]) were computed and each
expressed as a percentage of ventricular filling volume. The atrial reservoir
function was higher in the impaired relaxation group than in normal subjects
(49+/-8% vs 38+/-8%, p <0.01) but markedly lower in the restrictive group (27+/
8%, p <0.05). The reverse was true for conduit function, exaggerated in
restrictive group (54+/-12% vs 36+/-11% in normal subjects, p <0.01) but
minimized in patients with an impaired relaxation type of filling (14+/-9%, p
<0.001). The atrial pump contributed 19+/-6% of ventricular filling volume in
restrictives, 26+/-3% in normals (p <0.01), and 38+/-4% (p <0.001) in the
impaired relaxation group. We conclude that increased atrial response to early
stage left ventricular filling impairment is characterized by augmented reservoir
and pump functions, according to a Starling mechanism, which becomes hardly
effective at end-stage ventricular dysfunction when the limits of the atrial
preload reserve are reached. At this stage, conduit in the atrium takes
precedence.
PMID- 9761087
TI - Comparison of effects of ascorbic acid on endothelium-dependent vasodilation in
patients with chronic congestive heart failure secondary to idiopathic dilated
cardiomyopathy versus patients with effort angina pectoris secondary to coronary
artery disease.
AB - Impaired endothelium-dependent vasodilation has been reported to play an
important role in the pathogenesis of cardiovascular diseases such as coronary
artery disease (CAD) and congestive heart failure (CHF). However, the precise
mechanism of endothelial dysfunction has not been elucidated in these conditions.
To evaluate the role of oxidative stress in endothelial dysfunction, the effect
of antioxidant ascorbic acid on brachial flow-mediated, endothelium-dependent
vasodilation during reactive hyperemia and nitroglycerin-induced endothelium
independent vasodilation was examined with high resolution ultrasound in 12
patients with CHF caused by idiopathic dilated cardiomyopathy without established
coronary atherosclerosis and in 10 patients with CAD. Flow-mediated vasodilation
in CHF (4.4+/-0.5%) and CAD (4.0 - 0.8%) was significantly (p <0.05) attenuated
compared with that in 10 control subjects (9.6+/-0.9%). However, nitroglycerin
induced vasodilation was similar in 3 groups (13.7+/-1.3% in control, 13.9+/-1.1%
in CHF, 12.7+/-1.4% in CAD). Ascorbic acid could significantly improve flow
mediated vasodilation only in patients with CAD (9.1+/-0.9%) but not with CHF
(5.6+/-0.6%), and had no influence on nitroglycerin-induced vasodilation (13.6+/
1.1% in CHF, 14.0+/-1.3% in CAD). These results suggest that, in brachial
circulation, augmented oxidative stress mainly leads to endothelial dysfunction
in CAD but not in CHF caused by idiopathic dilated cardiomyopathy.
PMID- 9761088
TI - Likelihood of underreporting of outlet strut fracture from examination of the
Dutch Bjork-Shiley CC cohort.
AB - The Dutch Bjork-Shiley convexo-concave (BScc) cohort serves as a reference
population on the risk of outlet strut fracture and is being used to formulate
guidelines for prophylactic replacement. Fractures, however, may be undetected at
death. The aim of this study was to quantify the degree of underestimation of
strut fracture in the Dutch BScc cohort. Multivariate Cox regression analysis was
used to assess the relative and absolute risk of death from different causes
within 14 years. The unexplained "excess" mortality among 70 degrees BScc valve
recipients was attributed to unreported fatal strut fractures and used to
estimate its extent in this group, which then was extrapolated to the 60 degrees
BScc valve recipients. For 70 degrees BScc valve recipients, the adjusted hazard
ratio for death from all causes except strut fracture was 1.2 (95% confidence
interval [CI] 1.0 to 1.5). The 14-year absolute risks for 70 degrees and 60
degrees BScc valve recipients were 44% and 37%, respectively. Among 70 degrees
and 60 degrees BScc valve recipients, underreporting of fracture was estimated to
be 25% (95% CI 0 to 49) and 26% (95% CI 0 to 52), respectively. Estimates based
on sudden death and fatal congestive heart failure yielded essentially the same
results. Thus, underreporting of fatal strut fracture in the Dutch BScc cohort is
estimated to be approximately 25%. Hence, the risk and lethality of fracture of
BScc valves are underestimated and indications for prophylactic replacement
should be adjusted accordingly. For example, the advantage of valve replacement
in a 40-year-old patient with a 29-mm 60 micro BScc mitral valve would almost
double to 0.82 years.
PMID- 9761089
TI - Predictors of sudden cardiac death in hypertrophic cardiomyopathy.
AB - Patients with hypertrophic cardiomyopathy (HC) die suddenly. Proposed risk
factors for sudden cardiac death (SCD) in HC are youth, a family history of SCD,
syncope, and ventricular tachycardia. Hemodynamic variables have not convincingly
proved to be risk factors for SCD. Therefore, this study was designed to examine
predictors of SCD in a large number of patients with HC during long-term follow
up periods. The relation of studied variables (clinical, electrocardiographic,
echocardiographic, hemodynamic, and exercise test findings) to SCD in 309
patients with HC who were initially diagnosed during 1971 through 1994 (mean
follow-up 9.4 years) was examined by multivariate analysis. SCD occurred in 28
patients. Independent predictors of SCD were a smaller difference between peak
and rest systolic blood pressure during exercise testing (p=0.006), and higher
left ventricular outflow tract pressure gradient at rest (p=0.003). Exercise
related SCD occurred in 8 patients and exercise-unrelated SCD in 20 patients
(mean age 28 vs 47 years, p <0.05). Thus, patients of exercise-related SCD were
younger and had smaller increases in systolic blood pressure during exercise
testing, whereas patients with exercise-unrelated SCD were older and had higher
left ventricular outflow tract pressure gradient.
PMID- 9761090
TI - Risk stratification in patients with dilated cardiomyopathy: contribution of
Doppler-derived left ventricular filling.
AB - Dilated cardiomyopathy (DCM) is a major cause of mortality among patients with
heart failure. The aim of the present study was to investigate the independent
contribution of Doppler-derived left ventricular (LV) filling to the prediction
of survival in patients with DCM, of either ischemic or nonischemic origin, and
to derive a simple risk stratification score based on easily available clinical
and echocardiographic parameters. We followed 197 consecutive patients (159 men,
mean age 60+/-13 years) with an echocardiographic diagnosis of DCM (LV end
diastolic dimension >60 mm, fractional shortening <25%) over an average period of
62+/-13 months. The presumed etiology of DCM was ischemic in 52% of the patients.
During follow up, 69 patients died of cardiac causes and 41 required
transplantation. At 5 years, overall cardiac event-free survival was 55% and
freedom from death or heart transplantation was 43% (compared with 86% for the 5
year age- and sex-adjusted survival rate in our country). Kaplan-Meier survival
curves generated for different thresholds of the peak E velocity and the E/A
ratio indicated significant worsening of prognosis with increasing values of
these parameters in both ischemic and nonischemic patients. Using Cox stepwise
regression analyses, age (chi-square to remove 24.4; p <0.001), peak E velocity
(chi-square to remove=18.9; p <0.001), LV ejection fraction (chi-square to remove
6.4; p <0.011), and systolic blood pressure (chi-square to remove 4.5; p=0.034)
independently predicted cardiac deaths, whereas New York Heart Association (NYHA)
functional class (chi-square to remove 48.5; p < 0.001), LV ejection fraction
(chi-square to remove 19.1; p <0.001), E/A ratio (chi-square to remove 10.8; p
<0.001), and systolic blood pressure (chi-square to remove 5.8; p <0.016) were
independently associated with cardiac death or need for transplantation. Based on
these parameters, a risk score was elaborated, which allowed appropriate
classification of each individual patient into low- (5-year survival rate of
72%), intermediate- (46% survival rate), and high-risk groups (11% survival
rate). In conclusion, our data show that among the noninvasive parameters
commonly available in patients with either ischemic or nonischemic DCM, age, the
NYHA functional class, the LV ejection fraction, the systolic blood pressure, the
peak E velocity, and the E/A ratio provide relevant and independent information
regarding the risk of cardiac death or the need for heart transplantation.
PMID- 9761091
TI - Outcome of pregnancy following intervention for coarctation of the aorta.
AB - There are limited data regarding the outcome of pregnancy in women after
intervention for coarctation of the aorta (CoA). The Texas Children's Hospital
Cardiac Database was used to identify female patients with CoA born before 1980
who had undergone balloon angioplasty or surgery. Patients with Turner's syndrome
and cyanotic congenital heart disease were excluded. A chart review and telephone
interview were performed. Data collected included age at intervention, type of
intervention, the need for reintervention, functional status, number of
pregnancies, and pregnancy outcomes. Seventy-four patients met our criteria and
we were able to contact 52. Eighteen patients (39%) were pregnant a total of 36
times. There were 3 spontaneous and 4 elective abortions. Preeclampsia
complicated 4 pregnancies in 3 women (17% of primigravidas). One patient had
systemic hypertension. Eleven infants were delivered by Cesarean section. There
were 29 births, with an average weight of 3.0 kg. There were 5 preterm births, 4
to a teenage mother. Only 1 child (3%) had a congenital heart defect. Thus, in
women with an arm-to-leg blood pressure gradient of <20 mm Hg after CoA repair,
pregnancy is successful. The occurrence of congenital heart disease in the
offspring was 3%. Preeclampsia was similar to that in the general population.
PMID- 9761092
TI - Nosocomial infections in coronary care units in the United States. National
Nosocomial Infections Surveillance System.
AB - To describe the epidemiology of nosocomial infections in Coronary Care Units
(CCUs) in the United States, we analyzed data collected between 1992 and 1997
using the standard protocols of the National Nosocomial Infections Surveillance
(NNIS) Intensive Care Unit (ICU) surveillance component. Data on 227,451 patients
with 6,698 nosocomial infections were analyzed. Urinary tract infections (35%),
pneumonia (24%), and primary bloodstream infections (17%) were almost always
associated with use of an invasive device (93% with a urinary catheter, 82% with
a ventilator, 82% with a central line, respectively). The distribution of
pathogens differed from that reported from other types of ICUs. Staphylococcus
aureus (21%) was the most common species reported from pneumonia and Escherichia
coli (27%) from urine. Only 10% of reported urine isolates were Candida albicans.
S. aureus (24%) was the more common bloodstream isolate than enterococci (10%).
The mean overall patient infection rate was 2.7 infections per 100 patients.
Device-associated infection rates for bloodstream infections, pneumonia, and
urinary tract infections did not correlate with length of stay, number of
hospital beds, number of CCU beds, or the hospital teaching affiliation, and were
the best rates for comparisons between units. Use of invasive devices was lower
than in other types of ICUs. Overall patient infection rates were lower than in
other types of ICUs, which is largely explained by lower rates of invasive device
usage.
PMID- 9761093
TI - Use of harmonic imaging without echocardiographic contrast to improve two
dimensional image quality.
AB - The aim of this study was to determine whether harmonic imaging (HI) improves
endocardial visualization during 2-dimensional echocardiography without
echocardiographic contrast. HI differs from fundamental imaging (FI) by
transmitting ultrasound at one frequency and receiving at twice the transmitted
frequency. This technique has been used in conjunction with contrast
echocardiography to enhance myocardial contrast visualization. HI and FI were
sequentially performed in 20 patients. Images were digitally stored and
subsequently reviewed by 2 observers for the quality of endocardial
visualization. In addition, acoustic quantification was performed in both FI and
HI modes and endocardial tracking qualitatively judged. HI was compared with FI
during dobutamine stress echocardiography in 17 patients who were imaged at
baseline and peak stress. Overall, the harmonic images had less clutter and
better myocardial blood contrast. Individual segments were better visualized with
HI in 30% to 73% of cases. The acoustic quantification endocardial tracking was
rated better with HI in 67% of short-axis views and in 58% of apical 4-chamber
views. During dobutamine stress testing the overall number of interpretable
segments improved from 64% for FI to 84% with HI. Many segments traditionally
difficult to image were improved with HI. HI without the use of contrast agents
improved endocardial visualization during routine 2-dimensional echocardiography.
This improved endocardial visualization led to better endocardial tracking with
acoustic quantification and to more segments being clinically interpretable
during dobutamine stress testing.
PMID- 9761094
TI - "Rescue" abciximab for complicated percutaneous transluminal coronary
angioplasty.
AB - We studied the in-hospital outcome of 138 consecutive patients who received
abciximab as a "rescue" intervention for complicated coronary angioplasty in a
high-risk clinical setting. "Rescue" treatment with abciximab was associated with
clinical and angiographic success rates of 83% and 84%, respectively, whereas the
risk of bleeding was higher in patients of low body weight.
PMID- 9761095
TI - Clinical and angiographic outcome after stent placement for chronic coronary
occlusion.
AB - A consecutive series of 132 patients with total chronic coronary occlusions were
compared with 1,966 patients with stenotic lesions in terms of angiographic and
clinical outcome. We concluded that patients with chronically occluded coronary
lesions present a higher rate of target lesion revascularizations and
angiographic restenosis than patients with stenotic lesions.
PMID- 9761096
TI - Myocardial Doppler velocity imaging--a quantitative technique for interpretation
of dobutamine echocardiography.
AB - Myocardial Doppler velocity (MDV) imaging was evaluated as a quantitative method
for interpretation of dobutamine echocardiography by comparison with regional
wall motion abnormalities in 70 patients with known or suspected coronary artery
disease. Ischemic segments had the lowest increment of systolic MDV from rest to
peak dose, and using a peak MDV of <12 cm/s to define an abnormal response, the
sensitivity and specificity of MDV for ischemia was 86% and 96% for basal
segments, and 81% and 89% for mid segments.
PMID- 9761097
TI - Electrocardiographic correlates of absent septal q waves.
AB - Compared with 100 consecutive electrocardiograms with septal q waves, 100
consecutive electrocardiograms without septal Q waves were otherwise normal only
4 times (vs 28 times; p <0.001). The strongest electrocardiographic correlate was
QS in lead V1 (68 vs 4; p <0.001).
PMID- 9761098
TI - Comparison of double bolus urokinase versus front-loaded alteplase regimen for
acute myocardial infarction. Thrombolysis in Myocardial Infarction in Korea
(TIMIKO) study group.
AB - This study was performed to compare the double bolus urokinase regimen with the
front-loaded alteplase regimen for acute myocardial infarction. Double bolus
urokinase is an easy, safe, and effective thrombolytic regimen with comparable
results to standard front-loaded alteplase in acute myocardial infarction.
PMID- 9761099
TI - Increased QTc dispersion predicts lethal ventricular arrhythmias complicating
coronary angioplasty.
AB - This study found that increased QT dispersion just before angioplasty is an
useful marker to predict the risk for lethal ventricular arrhythmias during
angioplasty. The fact that successful coronary revascularization decreased QT
dispersion suggested that a part of increased QT dispersion is related to
myocardial ischemia.
PMID- 9761100
TI - Impact of heart rate and atrioventricular delay on left ventricular diastolic
filling in patients with dual-chamber pacing for sick sinus syndrome or
atrioventricular block.
AB - We examined the effect of left ventricular filling on different combinations of
programmable heart rate and atrioventricular delay in patients with dual-chamber
pacemakers. Pacing mode with heart rates of 60 beats/min and 156 ms of
atrioventricular delay induced a diastolic pattern that resembles more than
others the one observed in healthy subjects in sinus rhythm.
PMID- 9761101
TI - Usefulness of intravenous metoprolol to prevent syncope induced by head-up tilt.
AB - Intravenous metoprolol was found to be significantly more effective than placebo
in preventing head-up tilt-table induced neurally mediated syncope. The
reproducibility of acute tilt-table testing is only 63% and suggests caution in
the interpretation of acute drug testing during tilt-table studies.
PMID- 9761102
TI - A family study of anterior mitral leaflet thickness and mitral valve prolapse.
AB - To determine whether mitral valve prolapse (MVP) with or without mitral leaflet
thickening (> or =5 mm) represents distinct heritable conditions, 13 patients
with MVP with leaflet thickening and their relatives were compared with 67
patients with MVP with normal leaflets and their relatives. The 2 groups of
relatives had similar mitral leaflet thicknesses and similar long-term outcome,
arguing against the existence of a distinctive subtype of MVP characterized by
increased mitral leaflet thickness.
PMID- 9761103
TI - Results of transvenous buttoned device occlusion of patent ductus arteriosus in
adults. International Buttoned Device Trial Group.
AB - Examination of the immediate and follow-up results of transvenous buttoned device
occlusion of patent ductus arteriosus suggests that the method is feasible, safe,
and effective irrespective of the size and shape of the ductus. Although residual
shunts are present, they tend to disappear during follow-up, and complete
occlusion at the time of implantation may be achieved by incorporation of a
folding plug over the button loop of the device.
PMID- 9761104
TI - Effect of atenolol or metoprolol on arbutamine stress echocardiography in
patients suspected of having coronary artery disease.
AB - Arbutamine stress echocardiography was performed in 81 patients with suspected
coronary artery disease. Arbutamine infusion, using a dedicated closed-loop
delivery device, provided comparable myocardial stress in patients receiving beta
1 blockers versus those who were not.
PMID- 9761105
TI - Detecting exercise-induced ischemia in left bundle branch block using the
electrocardiogram.
AB - We compared 12-lead electrocardiographic changes during exercise in 41 patients
with left bundle branch block; 7 were nonischemic and 34 had coronary artery
obstruction > or =70% as detected by angiogram. ST depression of > or =0.5 mm
from baseline when measured at the J point in leads II and AVF (p=0.004) and an
increase of R-wave amplitude in lead II (p=0.05) significantly identified
ischemia.
PMID- 9761106
TI - Prediction of restenosis following percutaneous transluminal coronary
angioplasty: an important but elusive goal.
PMID- 9761107
TI - Dysfunction of the left atrium after cardioversion of atrial fibrillation.
PMID- 9761108
TI - A senior cardiologist does not have to be a senile cardiologist.
PMID- 9761109
TI - Dr. Howard B. Burchell is the greatest physiologic cardiologist of this century.
PMID- 9761110
TI - Does the size of the ventricular structure differ between Down's and non-Down's
patients, or between the Rastelli subtypes in complete atrioventricular septal
defect?
PMID- 9761111
TI - Plasminogen activator inhibitor-1 is an independent poor prognostic factor for
survival in advanced stage epithelial ovarian cancer patients.
AB - High levels of plasminogen activator inhibitor-1 (PAI-1) in tissue extracts have
been associated with poor prognosis in many epithelial cancers. Ovarian cancers
contain a higher concentration of PAI-1 than benign ovarian tumors or normal
ovaries. Reports, however, on the prognostic value of PAI-1 content in ovarian
cancers have been conflicting. We used immunohistochemistry to study the primary
and metastatic tissues from 131 epithelial ovarian cancer cases. This group has
been previously characterized for the expression of urokinase (uPA), uPA
receptor, PAI-2 and macrophage colony-stimulating factor (CSF-1). The intensity
and extent of staining for PAI-1 in the tumor epithelium was scored. Kaplan-Meier
curves of survival were compared using the log-rank test. The Cox regression
model was utilized for multivariate analysis. Approximately 50% of the primary
tumors and metastases expressed PAI-1. Among invasive stages III and IV patients,
those whose primary tumors expressed PAI-1 had a shorter overall survival. The
combination of strong expression of PAI-1 and expression of uPA was a highly
significant factor for short disease-free and overall survival. Similar results
were seen with the combination of high PAI-1 and low PAI-2 expression. Strong PAI
1 expression was significantly associated with expression of uPA receptor or CSF
I in the tumor epithelium, but not with standard clinical parameters, and was an
independent prognostic factor for poor survival on multivariate analysis. Our
results show that PAI-1 expression in the primary tumor epithelium is an
independent poor prognostic factor for survival, underscoring the tumor
protective role of PAI-1 in ovarian cancer biology.
PMID- 9761112
TI - Role of transforming growth factor beta3 in lymphatic metastasis in breast
cancer.
AB - Transforming growth factor-betas (TGFbetas) play a prominent role in tumour
growth and metastasis by enhancing angiogenesis and suppressing immune
surveillance. Despite the increased interest in the effect of TGFbetas on tumour
progression, little is known about the importance of TGFbeta3 and its receptor
CD105 in breast cancer. In the present study, we measured the plasma levels of
TGFbeta3, CD105-TGFbeta3 complexes and TGFbeta1 in 80 patients with untreated
early-stage breast cancer using an enhanced chemiluminescence ELISA method. Of
the 80 patients, 14 were histologically confirmed as having axillary lymph node
metastases, while the remainder had no evidence of lymph node involvement. The
results showed that levels of both TGFbeta3 and CD105-TGFbeta3 complex were
significantly elevated in patients with positive lymph nodes compared to those
without node metastasis. Furthermore, the levels of both TGFbeta3 and CD105
TGFbeta3 complex correlated with lymph node status. The only patient who died of
the disease had very high plasma levels of TGFbeta3 and CD105-TGFbeta3 complex
and positive lymph nodes; this patient developed lung metastases within 2 years
of diagnosis. No significant correlation was seen between either TGFbeta3 or
CD105-TGFbeta3 complex levels and tumour stage, size or histological grade.
Plasma TGFbeta1 levels were not correlated with node metastasis, tumour stage,
grade or size. Our data suggest that plasma levels of TGFbeta3 and CD105-TGFbeta3
complex may be of prognostic value in the early detection of metastasis of breast
cancer.
PMID- 9761113
TI - Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) proteolysis in
patients with colorectal cancer: possible association with the metastatic
potential of the tumor.
AB - The limited proteolysis of insulin-like growth factor (IGF)-binding protein
(IGFBP)-3 is a key event in the regulation of endocrine bioavailability of IGFs.
Here, we investigated IGFBP-3 and IGFBP-3 proteolysis in serum from patients with
colorectal cancer both before and at different times following surgery. In vivo
IGFBP-3 proteolysis, estimated by immunoblot analysis of IGFBP-3 fragments in
serum, and in vitro IGFBP-3 protease activity of serum, estimated by a 125I-IGFBP
3 degradation assay, allowed us to identify 2 groups of patients (IGF-M vs. IGF
NM) with respect to their status for mobilizing the IGF system. In IGF-M
patients, in vivo and in vitro IGFBP-3 proteolysis were significantly elevated
(156% and 181% of the age-matched control pool, respectively) and accompanied by
a decrease in intact IGFBP-3 (38% of the control pool). The IGFBP-3 proteolytic
processing was further increased in response to surgical ablation of the tumor
(mean increase 45-55%), then gradually returned to levels comparable with
controls. In contrast, IGF-NM patients exhibited a minimal alteration of in vitro
IGFBP-3 protease activity and even an inhibition of in vivo IGFBP-3 proteolysis,
whereas intact IGFBP-3 was unaltered when compared with controls. Moreover, this
pattern was not further significantly altered in response to the surgical stress.
None (0/6) of the IGF-M patients vs. 70% (5/7) of the IGF-NM patients developed a
metastatic disease (median duration of follow-up 26 months). Neither elevated
amounts of pro-IGF-II nor presence of detectable IGFBP-3 protease inhibitors in
the circulation could explain the observed suppression of IGFBP-3 proteolytic
processing in IGF-NM patients. These results indicate that inhibition of IGFBP-3
proteolysis and invasive properties of cancer cells are related in colorectal
cancer patients.
PMID- 9761114
TI - Heat shock protein expression and drug resistance in breast cancer patients
treated with induction chemotherapy.
AB - Heat shock proteins (Hsps) are induced in vitro by several cytotoxic drugs; in
human breast cancer cells these proteins appear to be involved in anti-cancer
drug resistance. The present report was designed to analyze whether chemotherapy
affects in vivo the expression of Hsp27, Hsp70, Hsc70 and Hsp90 in breast cancer
patients treated with induction chemotherapy and whether these proteins may be
determinants of tumor resistance to drug administration. We have analyzed 35
biopsies from breast cancer patients treated with induction chemotherapy.
Expression of the Hsps in the tumors was compared with (i) histological and
clinical responses to chemotherapy, (ii) tumor cell proliferation measured by
proliferating cell nuclear antigen (PCNA) immunostaining and nucleolar organizer
regions (AgNORs) staining and (iii) the expression of estrogen and progesterone
receptors. We also compared disease-free survival (DFS) and overall survival (OS)
with the expression of the Hsps studied. After chemotherapy, nuclear Hsp27 and
Hsp70 expression was increased and Hsp70 and Hsc70 cytoplasmic expression was
decreased. A high nuclear proportion of Hsp70 in tumor cells (>10%) correlated
significantly with drug resistance. We also observed that patients whose tumors
expressed nuclear or a high cytoplasmic proportion (>66%) of Hsp27 had shorter
DFS. The combination of Hsp27 and Hsp70 levels showed a strong correlation with
DFS. Neither the cellular proliferation nor the levels of steroid receptors
showed any significant difference before or after drug administration or during
follow-up of patients. Our results suggest that Hsp27 and Hsp70 are involved in
drug resistance in breast cancer patients treated with combination
chemotherapies.
PMID- 9761115
TI - Neopterin as a prognostic parameter in patients with squamous-cell carcinomas of
the oral cavity.
AB - Concentrations of neopterin, which is produced by human monocytes/macrophages
upon stimulation by interferon-gamma, were measured in urine specimens in 23
patients with squamous-cell carcinoma of the oral cavity at diagnosis and in 12
treated patients with the same disease when recurrence of the tumor was
recognized. Tumor histology and routine laboratory parameters were concomitantly
determined. Urinary neopterin values showed no statistically significant
correlation with tumor differentiation, tumor size or patient age, but they were
significantly higher in patients with a recurrent tumor. Patients were followed
for up to 4 years, and the ability of all variables to predict fatal outcome was
assessed. In univariate analysis, only neopterin (p = 0.01) and the variable
recurrent vs. first-diagnosed tumor were significant predictors of survival. In
multivariate analysis, a combination of neopterin (p < 0.01) and the variable
recurrent vs. first-diagnosed tumor (p = 0.06) was found to jointly predict
survival. Thus, urinary neopterin concentrations provide valuable prognostic
information in patients with squamous-cell carcinoma of the oral cavity.
PMID- 9761116
TI - The Epstein-Barr virus (EBV) major envelope glycoprotein gp350/220-specific
antibody reactivities in the sera of patients with different EBV-associated
diseases.
AB - gp350 of Epstein-Barr virus (EBV) induces a strong immune response in EBV
infected individuals, but relatively little is known about the clinical relevance
of this response in patients with different EBV-associated malignancies and other
diseases. Using our gp350-expressing cell clones, we studied gp350-specific
humoral immune responses in the sera of individuals with nasopharyngeal carcinoma
(NPC), chronic symptomatic EBV infection (CEI), Hodgkin's disease (HD), acute
infectious mononucleosis (IM) and healthy EBV-seropositive individuals (HI). The
titres of antibody-dependent cellular cytotoxicity (ADCC) antibodies were highest
in HI followed by CEI, HD and NPC. EBV-neutralizing (NA) and gp350-specific IgG
antibody profiles in these conditions were: CEI > HI > NPC > HD, whereas IgA
titres were the highest in NPC sera followed by CEI and HD. The sera from IM
patients were found to be negative for gp350-specific ADCC and IgA activities.
Sera from HI were also negative for gp350-specific IgA. A significant positive
correlation was found between serum gp350 IgA and viral capsid antigen IgA and a
significant negative one between IgM and ADCC titres. High IgA titres were also
found in CEI and EBV-genome positive HD in addition to NPC. Importantly, gp350
specific IgA titres were of prognostic value in NPC patients. Our data provide
new insights about the clinical relevance of gp350-specific immune responses in
these diseases.
PMID- 9761117
TI - CFTR deltaF508 carrier status, risk of breast cancer before the age of 40 and
histological grading in a population-based case-control study.
AB - There has been recent interest in the risk of various cancers in cystic fibrosis
(CF) patients and carriers of cystic fibrosis transmembrane conductance regulator
(CFTR) mutations. It has been proposed that a CFTR mutation may protect against
breast cancer, based on evidence that elevated extracellular adenosine
triphosphate (ATP) is known to inhibit breast cancer cell line growth and that
CFTR pumps ATP out of epithelial cells. A CFTR mutation would therefore result in
higher concentrations of serum ATP. A CFTR knockout mouse model had high serum
concentrations of ATP and showed reduced breast tumour implantibility and
decreased breast cancer growth rates. We have evaluated the relationship between
the deltaF508 CFTR mutation and the risk of breast cancer before the age of 40.
The deltaF508 CFTR mutation carrier rate in 272 cases (2.2%) was no different
from the carrier rate observed in 171 controls (1.8%). If there was a protective
effect resulting from the postulated elevation in serum ATP levels, tumours
arising in deltaF508 CFTR carriers would have been expected to be generally less
aggressive. When the histological features of the breast cancers with a deltaF508
CFTR mutation were reviewed and graded using a combined architectural and
cytological grading system, all were found to be grade III, poorly differentiated
tumours, contrary to the predictions. A combination of our data with other large
population-based samples of cases and controls is required to resolve this issue.
PMID- 9761118
TI - Chromosome 5 aberrations and genetic predisposition to lung cancer.
AB - In this study, we aimed to confirm the finding that chromosome 5 aberrations are
predisposing factors for lung cancer. The study population consisted of 118
previously untreated lung cancer patients and 101 healthy controls. Lymphocytes
were treated with bleomycin for 5 hr and then allowed to recover in a drug-free
medium for 48 hr. The mean number of cells with chromosome 5 abnormalities among
100 cells examined was significantly higher in patients (9.12) than in controls
(4.69) (p < 0.001). The most frequent aberration was a 5q deletion and the
breakpoints clustered at the 5q13-5q31 region. We then dichotomized the number of
induced chromosome 5 abnormalities in peripheral blood lymphocytes by the 75th
percentile in that of the controls. 103 (87.3%), of the 118 patients, but only 31
(30.7%) of the 101 controls, exhibited induced breaks above this point. After
adjustment for age, sex, ethnicity and smoking status, we found that the
sensitive group was at 14.4-fold increased risk for lung cancer. There was also a
significant (p < 0.01) gradient of increased risk for lung cancer with an
increasing number of chromosome 5 lesions. Therefore, chromosome 5 lesions,
especially those at 5q, may be a molecular target of carcinogens in the
development of lung cancer.
PMID- 9761119
TI - Quantitative analysis of p53 protein in non-small cell lung cancer and its
prognostic value.
AB - Accumulation of mutant p53 protein occurs frequently in human malignancies,
including 40-60% of non-small cell lung carcinomas. The implications of such p53
over-expression, usually assessed by immunohistochemical techniques, for the
prognosis of lung cancer patients remain undetermined. In this study, we used a
time-resolved immunofluorometric assay to measure p53 protein concentrations in
extracts prepared from 86 primary non-small cell lung tumours and examined the
associations between p53 protein levels (corrected for total protein) and other
clinico-pathologic variables, including post-surgical disease-free and overall
survival. Contingency tables analysed by chi2 tests revealed no significant
relationships between p53 status, defined by a median cut-off point, and patient
gender, age, disease stage, histologic grade and type, lymph node extension,
smoking history and administration of adjuvant chemotherapy or radiation.
However, multivariate Cox proportional hazard regression analysis demonstrated a
dose-response relationship between p53 concentration, expressed as a 4-level,
quartile-divided variable, and increased risk of relapse (p = 0.010) and death (p
= 0.016). Patients whose tumours contained p53 concentrations exceeding the
median value had over 3-fold higher risk of relapse (p = 0.002) and death (p =
0.007) than those whose tumours had lower p53 concentrations. We also provide
evidence suggesting that the impact of p53 on survival is greater in patients
with squamous cell carcinoma than in those with adenocarcinoma. Although the
latter finding needs confirmation, our results suggest that application of an
immunoassay of p53 protein on non-small cell lung tumour extracts may identify
patients at increased risk of unfavourable outcome.
PMID- 9761120
TI - Osteopontin expression in a group of lymph node negative breast cancer patients.
AB - The aim of this study was to examine the cellular distribution of osteopontin
(OPN) protein [by immunohistochemical (IHC) analysis] and mRNA [by in situ
hybridization (ISH)] in the primary tumors of lymph node negative (LNN) breast
cancer patients and to determine whether the level of immunodetectable OPN may be
associated with tumor aggressiveness. We examined OPN levels in tumors from 154
patients with LNN breast cancer who were followed for a median of 7 years (range
1.7-16.3 years). IHC staining for OPN was seen in tumor infiltrating macrophages
and lymphocytes in 70% of these tumors, and in the carcinoma cells themselves in
26%. ISH was performed to determine cellular distribution of OPN mRNA expression
in sections from selected tumors. OPN mRNA was detected in groups of tumor cells,
individual tumor cells and tumor infiltrating macrophages and lymphocytes.
Matched sections showed that some tumor cells with IHC staining for OPN protein
were also positive for OPN mRNA by ISH, in contrast with previous studies which
have shown OPN mRNA expression only in tumor infiltrating inflammatory cells. Our
results thus indicate that OPN protein can be produced by breast cancer cells in
vivo and suggest that it may also be taken up from the environment (i.e.,
secreted by inflammatory cells or other tumor cells). Tumor cell IHC staining
intensity was then assessed using a semiquantitative scoring system. Univariate
analysis showed tumor cell OPN positivity above an optimized cutpoint to be
significantly associated with decreased disease-free survival (DFS) and overall
survival (OS). The results of this pilot study thus suggest that the ability of
breast cancer cells to either synthesize OPN or to bind and sequester OPN from
the microenvironment may be associated with tumor aggressiveness and poor
prognosis.
PMID- 9761121
TI - Transmembrane 4 superfamily as a prognostic factor in pancreatic cancer.
AB - Several members of the transmembrane 4 superfamily (TM4SF) have been reported to
be related to tumor progression and metastasis. The aims of our study were to
clarify the relationship between TM4SF and pancreatic cancer and to determine the
prognostic significance of TM4SF in human pancreatic cancer. The mRNA levels for
MRP-1/CD9, KAI1/CD82 and ME491/CD63, which belong to the TM4SF gene family, were
evaluated in 40 resectable pancreatic adenocarcinomas using reverse transcriptase
PCR. MRP-1/CD9 gene expression was associated with lymph node status, and with
pathological status. Moreover, MRP-1/CD9 expression was inversely associated with
histo-pathological grading. KAI1/CD82 gene expression was inversely associated
with tumor status. ME491/CD63 gene expression, however, was conserved in all
pancreatic cancers. The overall survival rate for the 22 patients whose tumors
had decreased MRP-1/CD9 gene expression was strikingly lower than that for the 18
patients with MRP-1/CD9-positive tumors. The overall survival rate of the 15
patients who were KAI1/CD82-positive was significantly higher than that of the 25
patients with decreased KAI1/CD82 gene expression. In a multivariate analysis
using the Cox proportional hazards model, MRP-1/CD9 and KAI1/CD82 status was
found to be the most significant.
PMID- 9761122
TI - Association between genetic polymorphisms of glutathione S-transferase P1 and N
acetyltransferase 2 and susceptibility to squamous-cell carcinoma of the
esophagus.
AB - We examined the effect of genetic polymorphisms of phase-II enzymes, glutathione
S-transferase P1 (GSTP1) and N-acetyltransferase2 (NAT2) on susceptibility to
esophageal squamous-cell carcinoma To determine the genotypes of the 2
polymorphisms, PCR-based analysis was performed on samples from 66 Japanese
patients who had been histologically diagnosed as having esophageal squamous-cell
carcinoma, and 164 healthy Japanese controls. The frequency of the AA genotype of
GSTP1 was significantly higher in esophageal-cancer patients than in the controls
according to logistic-regression analysis (92% of the patients and 68% of the
controls; odds ratio (OR), 8.0; p = 0.0013). Also, more patients had the slow and
intermediate acetylator genotypes of NAT2 than the controls (15% and 38% vs. 10%
and 32% respectively; OR of the slow acetylator genotype, 4.2; p = 0.032; OR of
the slow plus intermediate acetylator genotypes, 2.9; p = 0.015). Polymorphisms
of GSTP1 and NAT2 may serve as genetic biomarkers for predicting susceptibility
to esophageal squamous-cell carcinoma.
PMID- 9761123
TI - Cox multivariate regression models for estimating prognosis of patients with
endometrioid adenocarcinoma of the uterine corpus who underwent thorough surgical
staging.
AB - The International Federation of Gynecology and Obstetrics (FIGO) adopted surgical
staging criteria in 1988. Many studies have shown that histologic grade, nuclear
grade, lymph-vascular space invasion and cell type are also important predictors
of survival. It has not been clarified, however, how to integrate these
histopathologic variables into the process of estimating individual prognosis. We
performed Cox multivariate regression analysis to create models that incorporate
various histopathologic factors for estimating the prognoses of patients with
endometrioid adenocarcinoma of the uterine corpus. Our study was based on data
from 206 patients who underwent complete surgical staging, including systematic
pelvic and para-aortic lymph node dissection. Two models resulted: one included
depth of myometrial invasion, para-aortic node metastasis and the number of sites
involved by the tumor among the cervix, ovary and pelvic lymph nodes (which we
designated as extracorporeal spread score, ECS) and the other incorporated
nuclear grade and lymph-vascular space invasion as variables. These 2 models
enabled the prognosis for patients with endometrioid adenocarcinoma to be
stratified into several levels according to hazard ratio. Comprehensive
integration of the histopathologic prognostic factors, categorized into those
relating to tumor extent and those relating to tumor virulence, should facilitate
the estimation of individual prognosis more accurately than FIGO staging alone.
PMID- 9761124
TI - Distribution pattern and risk factors of pelvic and para-aortic lymph node
metastasis in epithelial ovarian carcinoma.
AB - The distribution of lymph node metastasis and the clinicopathologic risk factors
for nodal involvement in ovarian carcinoma need to be clarified based on
systematic lymph node dissection. We studied 115 patients with ovarian carcinoma
who underwent systematic pelvic and para-aortic lymph node dissection between
1987 and 1997. The incidence and distribution of lymph node metastasis are
described and the clinico-pathologic risk factors for nodal involvement are
investigated. Based on the occurrence of lymph node metastasis in the early
stages, the incidence of solitary node involvement and the distribution of lymph
node metastasis, we conclude that the primary site of nodal involvement in
ovarian carcinoma is the para-aortic node (PAN), especially PAN superior to the
inferior mesenteric artery (IMA). By univariate analysis, clinical stage,
histologic type (mucinous vs. others), grade, multiple peritoneal metastases,
peritoneal cytology, volume of ascites and serum CA125 level were correlated with
overall incidence of lymph node metastasis. By performing a multivariate analysis
with the clinical stage excluded, it was revealed that grade and peritoneal
cytology were independent factors for PAN metastasis (p < 0.0025 and < 0.001,
respectively) and that multiple peritoneal metastases and PAN metastasis were
significant predictors of pelvic node metastasis (p < 0.01 and < 0.005,
respectively). In conclusion, the PANs superior and inferior to IMA should be
explored in staging of ovarian carcinoma that appears to be confined to the
ovaries. To determine accurately the extent of disease, both the para-aortic and
pelvic areas may need to be sampled or dissected in the case of ovarian carcinoma
involving the peritoneal surfaces.
PMID- 9761125
TI - Carcinomas of the renal pelvis associated with smoking and phenacetin abuse: p53
mutations and polymorphism of carcinogen-metabolising enzymes.
AB - Phenacetin abuse and smoking are established risk factors for transitional cell
carcinomas of the urinary tract. In the present study, we analysed exposure and
the clinical course of patients who underwent nephrectomy for transitional cell
carcinoma of the renal pelvis. PCR-SSCP of archival, paraffin-embedded
histological sections followed by direct DNA sequencing revealed that 29 of 89
(33%) renal pelvic carcinomas contained a p53 mutation. Double mutations were
found in 4 tumours and triple mutations in 1 tumour. The incidence of p53
mutations was significantly higher in tumours with grades 3 and 4 than in those
with grades 1 and 2 and higher in invasive than in non-invasive tumours.
Furthermore, patients with carcinomas carrying a p53 mutation showed poorer
survival than those without mutation. The type of p53 mutation in renal pelvic
carcinomas was similar to that reported for bladder cancer, G:C-->A:T transition
mutations being most frequent (45%, 33% of these at CpG sites), followed by G:C-
>T:A and G:C-->C:G transversions. The incidence and type of p53 mutation did not
differ significantly in patients with a history of phenacetin abuse, smoking or
neither of these habits. This was also true for G:C-->T:A transversions (17.5% of
mutations), which are considered typical of smoking-induced carcinomas at other
sites, e.g., lung, oral cavity and oesophagus. Our results indicate that the
frequency and pattern of p53 mutations are similar in transitional cell
carcinomas of the bladder and the renal pelvis and do not reflect exposure to
phenacetin and/or smoking. The frequency of genetic polymorphism in genes coding
for carcinogen-metabolising enzymes (CYP1A1, NAT1, GSTT1 and GSTM1) was also
independent of exposure. Although the sample size of our study does not allow
definite conclusions, these data are compatible with chronic tissue damage as a
causative factor in the evolution of urothelial carcinomas rather than pointing
to a direct mutagenic effect of phenacetin and tobacco-specific carcinogens.
PMID- 9761126
TI - Prognostic value of RET proto-oncogene point mutations in malignant and benign,
sporadic phaeochromocytomas.
AB - Somatic mutations in the RET proto-oncogene are involved in the pathogenesis of
an important subset (40-60%) of sporadic medullary thyroid carcinomas (MTCs) and
less frequently (0-31%) in benign, sporadic phaeochromocytomas. Since limited
data exist regarding the significance of somatic RET mutations in malignant
phaeochromocytomas, we analysed a multicentre series of proven malignant (i.e.,
metastasised) phaeochromocytomas. Analogous with MTCs, where RET mutations lead
to an aggressive behaviour, we hypothesised that somatic mutations would occur
more frequently in malignant than in benign phaeochromocytomas. Paraffin-embedded
tissue was available from 29 malignant and 27 benign phaeochromocytomas. Exons
10, 11 and 16 were analysed by non-radioactive single-strand conformation
polymorphism, heteroduplex gel electrophoresis, restriction enzyme digestion and
aberrant band patterns by non-isotopic sequencing. In only 1 of 29 malignant
phaeochromocytomas was a mis-sense mutation found (at codon 634 of exon 11),
whereas in 15% (4/27) of the benign tumours a point mutation was detected (in 3
tumours in exon 16 at codon 918 and in 1 tumour in exon 10 at codon 618). Absence
of these mutations in non-tumourous DNA proved their somatic origin. Contrary to
what has been reported for MTCs, oncogenic RET mutations are not associated with
an aggressive tumour behaviour in sporadic phaeochromocytomas.
PMID- 9761127
TI - Cytosol concentrations of CD44 isoforms in breast cancer tissue.
AB - The role of the adhesion molecule CD44 in the natural history of breast cancer is
controversial. We investigated the CD44 isoform CD44v5 and CD44v6 concentrations
in the cytosol of 90 breast cancer specimens, 9 fibroadenomas and 22 normal
breast tissue specimens by means of ELISA. CD44v5 and CD44v6 cytosol
concentrations were statistically significantly higher in breast cancer compared
with fibroadenoma and normal breast tissue (Mann-Whitney U-test, p = 0.009 and p
< 0.001, respectively). When CD44 isoforms were correlated with lymph node
involvement, histological grading, histological type, tumor stage and age at
diagnosis, we found no statistically significant correlation with any of the
investigated clinico-pathological parameters. In univariate and multivariate
analyses, CD44v5 and CD44v6 were of no prognostic relevance regarding disease
free survival in breast cancer patients (log-rank test, p = 0.16 and p = 0.08,
respectively). Our results indicate that CD44 isoforms are increased in samples
from tumors relative to normal tissue. Our data show that CD44v5 and CD44v6
isoform expression, although up-regulated by malignant transformation, is not
required to acquire a metastatic phenotype in breast cancer. Furthermore, our
data support the assumption that cytosolic CD44 isoforms are of no prognostic
relevance for disease-free survival of breast cancer patients.
PMID- 9761128
TI - Cytoplasmic accumulation of alpha-catenin is associated with aggressive features
in laryngeal squamous-cell carcinoma.
AB - Aberrations in the function of alpha-catenin (alpha-cat), the anchoring protein
of E-cadherin, are believed to cause dysfunction of the cadherin-catenin complex,
leading to disturbed cell-cell adhesion. It has been suggested that expression of
alpha-cat in human tumours might be a better indicator of aggressive phenotype
than expression of E-cadherin. The value of alpha-cat as a prognostic marker in
laryngeal squamous cell carcinoma (LSCC) is unclear. To determine the potential
prognostic significance of alpha-cat, paraffin-embedded samples from 159 patients
with invasive carcinoma left in the section and with long-term follow-up were
evaluated immuno-histochemically for alpha-cat expression, and the results were
related to histopathological grade, tumour stage and survival. Two patterns of
staining were observed: pure membranous staining (57%) and membranous staining
with cytoplasmic involvement (43%). Cytoplasmic involvement of alpha-cat was
associated with dedifferentiation, advanced tumour stage and nodal status. In
addition, supra-glottic tumours showed more often cytoplasmic involvement of
alpha-cat than glottic tumours. Patients with cytoplasmic involvement appeared to
have a trend towards poor overall survival, though without statistical
significance. These results suggest that cytoplasmic involvement of alpha-cat is
associated with aggressive behaviour and metastatic phenotype of LSCC.
PMID- 9761129
TI - Assessment of peripheral nerve function in an Ecuadorian rural population exposed
to pesticides.
AB - To explore the peripheral nervous system effects of regular agricultural
pesticide use, a cross-sectional survey was conducted in highland Ecuador.
Participants were 144 occupationally exposed farm members, 30 female farm members
with little direct exposure, and 72 unexposed local town residents, frequency
matched to the exposed people on age, sex, and education. Organophosphorus and
carbamate insecticides and dithiocarbamate fungicides accounted for the majority
of pesticide applications, with leaking backpack sprayers, minimal use of
personal protective equipment, and frequent dermal contact being the norm. In
polytomous logistic regression analyses, applicators had significantly greater
odds for more current peripheral nerve symptoms (odds ratio OR = 3.1), signs of
poor coordination (OR = 4.3), abnormal deep tendon reflexes (OR = 2.9), and
reduced power (OR = 2.1) compared to controls. Mean toe vibration threshold
scores, on a logarithmic scale, were significantly higher among applicators (beta
= 0.035) and those reporting previous pesticide poisonings (beta = 0.074). Such
indicators of peripheral nervous system effects may be due to a variety of
factors, including high pesticide exposure conditions.
PMID- 9761130
TI - Comparison of the effects of iodine and iodide on thyroid function in humans.
AB - Concerns have been raised over the use of iodine for disinfecting drinking water
on extended space flights. Most fears revolve around effects of iodide on thyroid
function. iodine (I2) is the form used in drinking-water disinfection. Risk
assessments have treated the various forms of iodine as if they were
toxicologically equivalent. Recent experiments conducted in rats found that
administration of iodine as I- (iodide) versus I2 had opposite effects on plasma
thyroid hormone levels. I2-treated animals displayed elevated thyroxine (T4) and
thyroxine/triiodothyronine (T/T3) ratios, whereas those treated with I- displayed
no change or reduced plasma concentrations of T4 at concentrations in drinking
water of 30 or 100 mg/L. The study herein was designed to assess whether similar
effects would be seen in humans as were observed in rats. A 14-d repeated-dose
study utilizing total doses of iodine in the two forms at either 0.3 or 1 mg/kg
body weight was conducted with 33 male volunteers. Thyroid hormones evaluated
included T4, T3, and thyroid-stimulating hormone (TSH). TSH was significantly
increased by the high dose of both I2 and I-, as compared to the control.
Decreases in T4 were observed with dose schedules with I- and I2, but none were
statistically significant compared to each other, or compared to the control.
This human experiment failed to confirm the differential effect of I2 on
maintenance of serum T4 concentrations relative to the effect of I- that was
observed in prior experiments in rats. However, based on the elevations in TSH,
there should be some concern over the potential impacts of chronic consumption of
iodine in drinking water.
PMID- 9761131
TI - Cytokine production by C57BL/6 mouse spleen cells is selectively reduced by
exposure to propanil.
AB - Numerous immunomodulatory effects are caused by propanil, an extensively used
postemergent herbicide. The T-dependent antibody response is suppressed after
exposure to propanil, raising the question of propanil's effect on T-helper-cell
populations. In the present study, we show that the production of several T-cell
cytokines is affected by propanil after in vivo or in vitro exposure. In vivo
exposure to propanil caused the reduction of interleukin (IL)-2, IL-6,
granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon (IFN)
gamma production in concanavalin A-stimulated spleen cell cultures established 2
d after exposure. IFN-gamma and GM-CSF production had recovered by d 4
postexposure; however, IL-2 and IL-6 levels continued to be depressed through d 7
postexposure. Continuous in vitro treatment of normal spleen cells with propanil
decreased IL-2, IL-6, GM-CSF, and IFN-gamma production after concanavalin A
activation. Pulsing normal spleen cell cultures with propanil for up to 8 h
before T-cell activation resulted in reduced IL-6 but not IL-2 or IFN-gamma
production. These data indicate that propanil can selectively inhibit spleen cell
cytokine production, which could contribute to the immunomodulatory effects
previously described.
PMID- 9761132
TI - Modulation of proto-oncogene expression by polychlorinated biphenyls in 3T3-L1
cell line.
AB - The effects of two substituted polychlorinated biphenyls, the 3,4,5,3',4,5' (PCB
169) and the 2,3,4,2',4',5' (PCB-138) forms, were examined on the expression of c
myc, c-jun, c-ras, and jun-b in 3T3-L1 cells. Northern blot analysis demonstrated
that the two PCBs, which exhibit a coplanar and di-ortho-substituted
configuration, activated these oncogenes differently. PCB-138 markedly induced
overexpression of ras, jun, and myc, whereas PCB-169 led to the overexpression of
jun-b. High-performance liquid chromatography analysis of the cell samples
treated in medium without serum revealed a higher intracellular concentration of
the 2,3,4,2',4',5'-hexachlorobiphenyl (hexaCB), whereas the 3,4,5,3',4'5'-hexaCB
reached the same concentration in the sonicated samples of cells with or without
serum. These results indicated that there was a relationship between PCB
structure, bioavailability, and the capacity to stimulate oncogene expression.
PMID- 9761133
TI - Subchronic toxicity of benzothiophene on rats following dietary exposure.
AB - The systemic and neurobehavioral effects of benzo[b]thiophene (routinely referred
to as benzothiophene) were studied in rats following 13-wk oral exposure. Male
(170 +/- 16 g) and female (146 +/- 12 g) Sprague-Dawley rats (10 animals per
group) were fed diet containing 0.5, 5, 50, or 500 ppm benzothiophene for 13 wk.
Control animals were given rat feed plus vehicle (corn oil) only. No clinical
signs of toxicity and neurobehavioral effects were observed using screening tests
that included cage-side observations, righting reflex, open field activities, and
forelimb and hindlimb grip strength. Elevated serum aspartate aminotransferase
activity and bilirubin level were observed in highest dose females. Except for a
statistically significant decrease in hematocrit in the highest dose males,
benzothiophene exerted no marked effects on hematological parameters.
Benzothiophene exposure did not result in alterations in hepatic alkaline
phosphatase activity, or the typical hepatic phase I (aniline hydroxylase,
ethoxyresorufin O-deethylase, pentoxyresorufin O-dealkylase, aminopyrine N
demethylase) and phase II (UDP-glucuronosyltransferase, glutathione S
transferase) drug-metabolizing enzyme activities. No significant elevation in
urinary ascorbic acid, protein, and N-acetylglucosaminidase activity was detected
in the treated animals. Peribiliary fibrosis was the most significant
histological change and occurred in the liver of females in the 50 and 500 ppm
groups. Mild epithelial hyperplasia in the renal pelvis was detected in the
majority of 5 and 50 ppm females, with epithelial hyperplasia in the urinary
bladder observed in the 50 ppm females. In males, increased incidence and
severity of mild binucleation of hepatocytes and mild thickening of the basement
membrane in kidney cortex were observed at 500 ppm. Benzothiophene was not
detected in the urine of high-dose animals at the termination of the experiment.
Based on the kidney, hepatic, and hematocrit changes, the no-observed-adverse
effect level (NOAEL) in the diet was determined to be 0.5 ppm (0.04 mg/kg/d) for
females and 50 ppm (3.51 mg/kg/d) for males.
PMID- 9761134
TI - Modulation of metal-induced cytotoxicity by maillard reaction products isolated
from coffee brew.
AB - Nondialyzable Maillard reaction products (MRPs) were recovered from three
different coffee brew extracts (i.e., brewed, boiled, instant) to evaluate the
efficacy of MRPs in modulating in vitro metal-induced cytotoxicity in C3H/10T1/2
mouse embryo fibroblast cells, cultured in the presence of Fe2+, Fe3+, or Cu2+
ions. Preliminary experiments were performed in an vitro linoleic acid emulsion
model system to characterize the anti- or pro-oxidant activity of coffee MRPs.
Cytotoxicity experimental protocols involved both the direct application of metal
ions and coffee MRPs to fibroblast cells, and the premixing of metal ions with
coffee MRPs at room temperature prior to incubating with fibroblast cells. Fe2+
and Cu2+ significantly lowered the colonization efficiency (CE) of cells at all
three concentrations (i.e., 0.1, 10, 50 microM) used. Similar Fe3+ activity was
observed only at 50 microM concentration. None of the coffee MRPs alone or
together with 0.1 and 10 microM of Fe2+ or Fe3+ produced cytotoxic effects during
direct application. The premixing step, however, significantly enhanced the CE of
cells compared to the control, denoting cytoprotection, only in the presence of
Fe2+. In addition, the application of MRPs with 0.1 or 10 microM of Cu2+
significantly lowered the CE of cells than the control, but enhanced the CE of
cells than the Cu2+ added control. These results corresponded directly with the
results of model linoleic acid emulsion test, thereby demonstrating that lipid
hydroperoxide generation is the source for fibroblast cell toxicity when MRPs are
added to cells together with metal ions. These results further indicate that
coffee MRPs can suppress in vitro metal-induced cytotoxicity to a certain extent
when Fe2+, Cu2+, or Fe3+ ions are present below a concentration of 50 microM,
possibly by chelating the metal ions. Ionic reducing capacity of coffee MRPs,
albeit small, may explain the potential for increased cytotoxicity at higher
coffee MRP concentrations.
PMID- 9761135
TI - Publication bias in nursing research.
PMID- 9761136
TI - Extended care referral after hospital discharge.
AB - The purpose of this study was to describe the influence of selected
organizational and medical factors on communication between hospitals and
extended care facilities (ECF) in the referral of elderly clients following
discharge from acute care. Using a tool with previously established reliability
and validity, 455 closed records of referral were purposively selected and
reviewed for the amount and type of information an ECF received upon referral, as
well as selected organizational and medical factors. Hospitals transferred
approximately three-fourths of the patient care data recommended in the
literature. Information contained in an ECF referral consisted primarily of
background and medical data, with some nursing care data and limited psychosocial
data. More information-rich referrals were generated by very large hospitals and
by specialty care units. Similarly, proprietary ECFs received more patient care
data than their not-for-profit counterparts. Research concerning patient care
communication between provider organizations across the health care delivery
system may assist nurses in developing better patient care information-management
systems.
PMID- 9761137
TI - Development and evaluation of the Osteoporosis Self-Efficacy Scale.
AB - The Osteoporosis Self-Efficacy Scale was developed as a measure of self-efficacy,
or confidence, for behaviors related to physical activity and calcium intake. An
item pool of 21 statements, responded to on a visual analog self-report format,
was reviewed by a panel of expert judges. The revised item stems were tested with
a sample of 201 women, ages 35 to 95. Concurrent data on sport, leisure, and
exercise activity and calcium in diet and dietary supplements were collected from
the respondents. Factor analysis of responses to the self-efficacy items revealed
a logical, theoretically meaningful two-factor structure, one for physical
activity and one for calcium intake. Internal consistency estimates for each of
the two factors were in the .90s. Convergent and discriminant validity analyses
as well as hierarchical regression analyses to explain self-reports of physical
activity and calcium intake were supportive. The final version of the brief,
psychometrically sound scale contains items reflecting initiation, maintenance,
and persistence at osteoporosis preventive behaviors; thus, the Osteoporosis Self
Efficacy Scale is a potentially beneficial research instrument.
PMID- 9761138
TI - The impact on quality of life of patient-related barriers to pain management.
AB - A stress-coping model of relationships between patients' beliefs about pain,
coping (analgesic use), pain severity, analgesic side-effects, and three quality
of life (QOL) outcomes was tested. Participants were 182 men and women with
cancer who completed valid and reliable self-report measures of relevant
variables. Antecedent variables (age and education) showed expected relationships
with beliefs. As predicted, beliefs were significantly related to analgesic use.
Analgesic use was inversely related to pain severity, but was not related to side
effect severity. Analgesic use was inversely related to impairments in QOL before
controlling for pain and side-effect severity, but not after these two variables
were controlled. Both analgesic side-effects and pain severity were related to
impaired QOL outcomes, including difficulty performing life activities, depressed
mood, and poor perceived health status.
PMID- 9761139
TI - A causal model of voluntary turnover among nursing personnel in long-term
psychiatric settings.
AB - Causal modeling was used to explore the processes by which individual
characteristics, job satisfaction, and intention to quit explain turnover among
nursing personnel in 29 Department of Veterans Affairs (VA) long-term psychiatric
settings. The sample consisted of 1,106 registered nurses (RNs), licensed
practical nurses (LPNs), and nurses' aides. We conceptualized turnover as a
multistage process linking social and experiential orientations, attitudes toward
the job, the decision to quit, and the behavior of actually quitting. Intention
to quit was the strongest direct predictor of turnover. Professional growth
opportunities and workload were important indirect predictors of turnover.
Dissatisfaction with work hazards and relationships with coworkers were both
indirect and direct predictors of turnover. Attitudes towards the job varied by
nursing group. LPNs and aides were less satisfied than RNs with autonomy and work
hazards. RNs were more dissatisfied with workload. We conclude that strategies to
promote retention need to address aspects of jobs tailored to specific nursing
groups.
PMID- 9761140
TI - Australian nurses' experiences and attitudes in the "Do Not Resuscitate"
decision.
AB - The effects of Australian nurses' (n=285) awareness of a "Do Not Resuscitate"
(DNR) policy and various practice settings on the DNR decision were examined. A
questionnaire, developed by the investigator, was used to gauge nurses'
experiences and attitudes in DNR practice. Decision making was not significantly
affected by nurses' awareness of a DNR policy in hospitals where a policy was
present. Although nurses believed that the patient, next-of-kin, and nurse should
play a predominant role in the DNR decision, medical staff were usually
responsible for the decision. Various strategies are suggested as to how nurses
could make a greater impact on the DNR decision.
PMID- 9761141
TI - Decision-making models in different fields of nursing.
AB - The purpose of this study was to identify the decision-making models used by
nurses in different fields of nursing and to find out which variables explain the
use of those models. The instrument for the project was developed on the basis of
existing decision-making theories and earlier studies on nurses' decision making.
The sample consisted of 483 Finnish nurses from five fields of nursing: long-term
care, short-term medical-surgical care, critical care, health care, and
psychiatric care. The statistical analyses consisted of factor analysis, factor
scores, and correspondence analysis. Five different models of nursing decision
making were identified. The nature of the nursing task and the nursing context
showed associations with decision making on all models. The structure of
knowledge and nurses' practical experience did not provide an explanation for
nurses' decision making on any model.
PMID- 9761142
TI - Development of the Rural-Urban Demand Indicator (RUDI).
AB - In this article we describe development of RUDI (Rural-Urban Demand Indicator), a
multivariate interval level measure of demand for health services. RUDI ranks
counties by population and purchasing power and was developed for use in a wide
variety of health-related research and for policy analyses. RUDI is based on
microeconomic theory and Grossman's (1972) extension of the theory, that the
family produces health and that the family's demand for health services is
derived from the demand for health. Two factors define RUDI: DEMOS (demographics)
and EWB (economic well-being). These two factors accounted for 66.2% of the
variance observed in 1990 census data. A variety of other analyses offer evidence
of known- groups, convergent, factorial, and predictive validity.
PMID- 9761143
TI - The call to experts in qualitative research.
AB - There are many researchers engaged in qualitative research who look to experts in
this mode of inquiry to validate their findings. But can any outsider, even an
"expert" in qualitative research, do this? Such an expert is unlikely to know the
data as well or to be as fully immersed in the project as the researcher. There
are different kinds of expertise that may be required for different phases and
purposes of research, and to satisfy different epistemological and ethical
concerns. Moreover, new modes of participatory research have complicated the role
of expert and the idea of expertise. Researchers must be judicious in their
claims to expert validation, and experts must move researchers away from a
preoccupation with validation toward craftsmanship and accountability to diverse
communities.
PMID- 9761144
TI - Management of the abnormal cervical smear and a historical review of cone biopsy
in Victoria.
PMID- 9761145
TI - Diagnosis and treatment of cervical intraepithelial neoplasia in a single visit.
AB - We evaluated the diagnostic and therapeutic efficacy of large loop excision of
the transformation zone (LLETZ) performed in the first visit (see and treat
policy) as compared to LLETZ treatment performed as an interval procedure. Data
of 248 patients were analyzed of which 206 patients had LLETZ. Two thirds of the
procedures were performed at the first visit. Of all the women who had the 'see
and treat policy' 94.9% were diagnosed to have cervical intraepithelial neoplasia
(CIN) on histology compared to 90.8% in the interval treatment group. A total of
3 (1.4%) patients were detected to have microinvasive carcinoma. There was no
difference in the immediate postoperative complication rate, overtreatment rate
and need of repeat treatment in both the groups. Single visit colposcopy and loop
treatment is a safe and effective option for treatment of cervical epithelial
abnormalities. The experience of the colposcopist is very important.
PMID- 9761146
TI - The use of large loop excision of the transformation zone in management problems
of cervical intraepithelial neoplasia.
AB - We studied 2 groups of women whose management is controversial: those with
cervical intraepithelial neoplasia (CIN) grade 2 or 3 on smear, but only CIN
grade 1 or no abnormality on target biopsy (Group 1), and those with persistent
CIN grade 1 on smear and up to CIN 1 on biopsy (Group 2). We set out to assess
whether large loop excision of the transformation zone (LLETZ) was an acceptable
method of treating these 2 groups of women. A review of 100 consecutive patients
was undertaken. There were 71 women in Group 1 and 29 women in Group 2. The LLETZ
procedures were performed under local analgesia and no immediate problems were
encountered. Delayed haemorrhage requiring vaginal packing and admission to
hospital occurred in 1 patient. In Group 1, histopathology of the LLETZ biopsies
showed CIN 2 or 3 in 29 (40.8%) of the women, CIN 1 in 24 (33.8%) and no CIN in
18 (25.3%), and in Group 2, CIN 2 or 3 was seen in 5 (17.2%) of the women, CIN 1
in 11 (37.9%) and no CIN in 13 (44.8%). At 12 months completed follow-up, 4
patients in Group 1 had recurrent CIN 1 or equivocal CIN 1 and 1 patient from
Group 2 had recurrent CIN 1, giving an overall recurrence rate of 5 of the 94
patients who completed follow-up (5%). We concluded that LLETZ was a useful
procedure in both groups. In Group 1 the provision of a histological diagnosis on
the LLETZ biopsy was a check on the accuracy of the cervical smear report. In
Group 2, LLETZ offered the advantage of rapidly returning the smear to normal in
most patients, and the diagnosis and treatment of those women who actually had a
high-grade lesion.
PMID- 9761147
TI - High prevalence of chlamydia and Pap-smear abnormalities in pregnant adolescents
warrants routine screening.
AB - A prospective cohort of pregnant adolescent patients who planned to deliver at 1
of 3 Perth metropolitan hospitals was studied; 1 subgroup of this cohort was
offered universal screening for cervical chlamydial infection and Pap-smear
abnormalities (screened), and the remainder of the cohort were offered screening
at the discretion of the attending medical staff (control). High prevalences of
both chlamydial infection (27%) and Pap-smear abnormalities (38%) were detected
in the screened cohort. The majority of Pap-smear abnormalities were inflammatory
atypia, but high-grade Bethesda lesions were also diagnosed. In the control
group, the prevalence of positive swabs and abnormal Pap-smear reports in those
tested was also high (22% and 35% respectively), but significantly fewer patients
were tested (18% and 33% respectively in the control group, compared to 92% and
94% in the screened group; both p<0.001). Screening and treatment of chlamydia
was associated with a significant decrease in the incidence of newborn febrile
morbidity (10% versus 25%; p=0.02). In view of the high prevalence of positive
results, it is cost-effective to offer universal screening in this setting.
Failure to introduce a specific screening policy can result in a significant
number of patients being denied the advantages of diagnosis and treatment.
PMID- 9761148
TI - The incidence of abnormal findings from intrapartum cardiotocogram monitoring in
term and preterm labours.
AB - A retrospective analysis of 514 consecutive labours delivering 530 babies over a
period of 18 months was conducted by a high-risk pregnancy team in a tertiary
teaching unit to compare the incidence of abnormal findings from intrapartum
monitoring between labours occurring before and at or after 34 weeks' gestation.
Those delivered by elective Caesarean section, or Caesarean section at the onset
of labour because of contraindications to labour and vaginal delivery, and those
with congenitally malformed fetuses were excluded. Tracings were scored using the
FIGO 1987 guidelines. Seventy-four labours and 83 babies delivered before 34
weeks, and 440 labours and 447 babies delivered after 34 weeks in the study.
There was a slightly higher incidence of suspicious CTG tracings (33.7% versus
19.6%, OR 2.66, 95% CI 1.6-4.4) in the preterm group, due mainly to decreased
baseline variability (p<0.001, OR 3.57, 95% CI 1.8-6.9), but the incidence of
other pathological patterns did not differ. Using the same set of criteria for
interpretation, there was a higher incidence of abnormalities from continuous
cardiotocogram monitoring in the preterm group compared to term labours, but the
intervention rate for fetal distress was not significantly increased. Appropriate
interpretative criteria for intrapartum monitoring of preterm labours should be
devised.
PMID- 9761149
TI - Accuracy of automated blood pressure recorders in pregnancy.
AB - Automated blood pressure recorders are used with increasing frequency by pregnant
women, mostly without proper evaluation of their accuracy. We compared blood
pressures (BP) recorded by 2 automated noninvasive devices, the Spacelabs 90207
ambulatory blood pressure monitor and the OMRON HEM 705 CP portable self
initiated device, with blood pressures recorded by routine sphygmomanometry in 79
pregnant women either considered 'at risk' for preeclampsia or with mild
hypertension in pregnancy. The Spacelabs device tended to overestimate systolic
BP by a mean 11 (SD=8) mmHg and diastolic BP by 5 (SD=7) mmHg for phase 5
pressure (p<0.001) but was similar to routine BPs for diastolic phase 4
pressures. The OMRON device tended to underestimate diastolic (phase 4) pressure
by 4 (SD=6) mmHg (p<0.001) but gave similar systolic and diastolic (phase 5)
pressures to routine sphygmomanometry. However, for both devices there was
considerable individual patient variability in accuracy. When using these devices
to record a limited number of blood pressure recordings, as in this study, we
suggest that individual comparison with mercury sphygmomanometry be made in each
pregnant woman before accepting the validity of these recordings.
PMID- 9761150
TI - Pregnancy and congenital heart disease--maternal and fetal outcome.
AB - Two hundred and seventy five pregnancies in patients with congenital heart
disease during 1980-1996 were analyzed retrospectively. Maternal and perinatal
outcome was compared in 251 pregnancies of women with acyanotic and 24
pregnancies of women with cyanotic heart disease. Congenital heart disease was
diagnosed during the index pregnancy in 26.1% of patients and the majority
(88.4%) were in NYHA classes 1 and 2. Atrial septal defect (27.7%) was the most
common lesion in women with acyanotic heart disease and the majority with
cyanotic heart disease had Eisenmenger syndrome, 13 of 21 (61.9%). Sixty
pregnancies occurred in patients with surgically corrected lesions (acyanotic,
56; cyanotic, 4). The incidences of abortions (8.3%), stillbirths (13.6%) and
small for gestational age (SGA) (36.4%) were higher in cyanotic heart disease
compared to acyanotic heart disease (stillbirth, 0.8%; SGA, 6.9%). There was a
statistically significant difference in mean maternal age, mean gestational age
and mean birth-weight in the surgically corrected and noncorrected lesions in
both acyanotic and cyanotic heart disease. There was 1 maternal death in a woman
with Eisenmenger syndrome.
PMID- 9761151
TI - Intrapartum fetal oxygen saturation monitoring in congenital fetal heart block.
AB - Conventional intrapartum electronic fetal heart rate monitoring is not
informative in certain fetal conditions because the electronically-monitored
fetal heart rate pattern is uninterpretable in terms of reflecting fetal
normoxia. Such fetal conditions include various cardiac dysrrhythmias and some
central nervous system abnormalities. Difficulties with intrapartum fetal welfare
surveillance in such conditions often lead to operative delivery as a
precautionary measure. We report 2 cases of intrapartum fetal oxygen saturation
monitoring in the presence of congenital complete heart block (CCHB), using the
Nellcor N400/FS14 oxygen saturation monitoring system. Mean intrapartum fetal
oxygen saturation (FSpO2) was 32% (SEM +/- 1%) in the first case and 48% (SEM +/-
0.3%) in the second case. In both cases, vaginal delivery of otherwise healthy
infants was achieved. Fetal pulse oximetry is a promising new technique which
directly measures fetal oxygenation without reference to fetal heart rate
patterns. It may assist in the intrapartum fetal welfare assessment in conditions
such as complete heart block, thereby helping to avoid otherwise unnecessary
operative delivery.
PMID- 9761152
TI - Induction of labour for post term pregnancy: an observational study.
AB - The aim of the study was to compare the 2 management protocols for postterm
pregnancy; elective induction of labour at 42 weeks' gestation and continuing the
pregnancy with fetal monitoring while awaiting spontaneous labour. A
retrospective observational study compared a cohort of 360 pregnancies where
labour was induced with 486 controls. All pregnancies were postterm (>294 days)
by an early ultrasound scan. Induction of labour was achieved with either
prostaglandin vaginal pessaries or gel or forewater rupture and Syntocinon
infusion. The control group consisted of women with postterm pregnancies who were
not induced routinely and who usually had twice weekly fetal assessment with
cardiotocography and/or ultrasound. Women who had their labour induced differed
from those who awaited spontaneous labour. Nulliparas (OR 1.54; 95% CI 1.24-1.83)
and married women (OR 1.76; 95% CI 1.45-2.06) were more likely to have their
labour induced. There was no association between the type of caregiver and
induction of labour. Induction of labour was associated with a reduction in the
incidence of normal vaginal delivery (OR 0.63, 95% CI 0.43-0.92) and an increased
incidence of operative vaginal delivery (OR 1.46; 95% CI 1.34-2.01). There was no
difference in the overall rate of Caesarean section. There was no difference in
fetal or neonatal outcomes. Parity had a major influence on delivery outcomes
from a policy of induction of labour. Nulliparas in the induced group had worse
outcomes with only 43% achieving a normal vaginal delivery (OR 0.78, 95% CI 0.65
0.95). In contrast for multiparas, the induced group had better outcomes with
less Caesarean sections (OR 0.88, 95% CI 0.81-0.96). This retrospective
observational study of current clinical practice shows that induction of labour
for postterm pregnancy appears to be favoured by nulliparous married women. It
suggests that induction of labour may improve delivery outcomes for multigravas
but has an adverse effect for nulliparas.
PMID- 9761153
TI - Use of a focussed teen prenatal clinic at a military teaching hospital: model for
improved outcomes of unmarried mothers.
AB - We evaluated the utility of a focussed, multidisciplinary adolescent clinic in
improving perinatal outcomes. The study population included all delivering
unmarried teenagers (13-19 years) from January 1, 1993 to December 31, 1995
attending the focussed adolescent obstetrical clinic compared to a similar cohort
of married teenagers (13-19 years), married 20-24 year-old patients, and
unmarried 20-24 year-old patients. There were no statistical differences in
chorioamnionitis, intrauterine growth retardation (IUGR), postpartum haemorrhage,
maternal weight gain, mean gestational age at delivery, preterm delivery rates
(<37 weeks), low birth-weight (<2,500 g), Caesarean delivery, postterm delivery
rates (>41 weeks), macrosomia (>4,000 g), placental abruption, chronic
hypertension, alcohol use, Apgar scores or stillbirth rates or neonatal death
rates among the 4 groups studied. Statistical differences were noted in mean
delivery weights (p<0.05), preeclampsia (p<0.004), gestational diabetes (p<0.01),
history of substance abuse (p<0.0001), tobacco use (p<0.0001), and forceps
delivery rates (p<0.004). However, in the teen cohort none of these differences
appeared to adversely affect perinatal outcomes in our patients. The focussed,
adolescent obstetrical clinic appears to provide perinatal morbidities equal to a
low-risk, general population generating better than expected outcomes for
pregnant teenagers.
PMID- 9761154
TI - Primipaternities in families: is the incidence of pregnancy-induced hypertensive
disorders in multigravidas an anthropological marker of reproduction?
AB - Pregnancy-induced hypertensive disorders (and especially preeclampsia) remain
nowadays the major problem of human reproduction as it occurs in at least 10% of
all world population births. It is a major cause of maternal-fetal mortality and
morbidity in developed and developing countries. This disease was until recently
classically considered as a disease of primigravidas with little recurrence in
multigravidas. Nevertheless, recent evidences in the last half decade suggest
that this disease is indeed a disease of first pregnancies, but at the level of a
couple (primipaternity) rather than only the mother's side (primigravidity).
Therefore, multigravidas share the risk with primigravidas in case of conception
with a new partner. We expose the biological plausibility of this new approach
(immunogenetic factors), and propose its epidemiological consequences with
proposals of future research for health workers or demographers working at the
level of populations. If pregnancy-induced disorders are disease of new couples,
then their patterns are probably very different according to the broad
reproductive patterns existing among different cultures (contraception,
matrifocality or patrifocality, age at marriage, changes of reproductive partners
et cetera).
PMID- 9761155
TI - Maternal and umbilical cord serum zidovudine levels in human immunodeficiency
virus infection.
AB - The aim of this study was to determine the maternal and umbilical cord serum ZDV
levels at delivery in HIV-1 infected parturients treated with a short-course ZDV
regimens in late pregnancy and labour. Serum ZDV and its metabolite were measured
by high-performance liquid chromatography. Concentrations of ZDV and its
metabolite in umbilical cord blood appeared similar to maternal concentrations.
There was a significant positive correlation between serum ZDV and its metabolite
in maternal and umbilical cord concentrations. At delivery, maintenance of
optimal virustatic ZDV concentration with oral antenatal and oral intermittent
intrapartum ZDV dosage regimen can be achieved in only 53% of cases. The regimens
used in this study were useful but not as effective as the ACTG 076 regimen with
an intravenous dose intrapartum plus the oral administration to the infants for 6
weeks.
PMID- 9761156
TI - Timing and mechanism of perinatal human immunodeficiency virus-1 infection.
AB - There is sufficient evidence indicating a higher vertical HIV-1 transmission rate
in the last trimester and during labour compared with the first trimester.
Antiretroviral therapy either single or in combination given to the mother during
the last trimester and delivery can reduce the viral load in the maternal
circulation. Vertical HIV-1 transmission during delivery can be minimized by
appropriate timing and route of delivery. Elective Caesarean section before the
onset of labour with an intact bag of forewaters provides the least mother-to
fetus microtransfusion compared to other modes of delivery. Since an effective
combination of HIV-1 immunoglobulin and HIV-1 vaccine given to the HIV-1 exposed
newborns to prevent HIV-1 transmission similar to the viral hepatitis B model is
not firmly established at present, postexposure antiretroviral prophylaxis and
nonbreast-feeding are advocated for infants born from the HIV-1 infected mothers.
In cases of advanced stage of maternal HIV-1 infection, and in developing areas
where malnutrition prevails, an adequate supply of essential micronutrients is
proposed as an adjunctive measure to reduce HIV-1 perinatal transmission.
PMID- 9761157
TI - Preterm infants 30-36 weeks' gestation in Victoria--where should they be
delivered?
AB - There is little doubt that very preterm infants <30 weeks' gestation should be
born in level-3 perinatal centres. For preterm infants 30-36 weeks' gestation,
however, the optimum place of birth is not so clear-cut. The aims of this study
of livebirths 30-36 weeks' gestational age born in Victoria were to determine: 1)
the proportions delivered outside level-3 centres, and 2) for infants born
outside level-3 centres, the proportions transferred after birth to a level-3
nursery in the first days after birth. Data on the number of livebirths 30-36
weeks' gestational age in Victoria in the 3 years 1994-1996, inclusive, were
supplied by the Victorian Perinatal Data Collection Unit. Data were obtained from
the Newborn Emergency Transport Service (NETS) on all transfers within the first
3 days after birth to a level-3 centre for infants born outside level-3 centres.
For the 3 years 1994-1996 there were 11,375 livebirths 30-36 weeks' gestational
age in Victoria. The proportion born outside a level-3 perinatal unit was 57.9%
overall, and rose with increasing gestational age, from 10.9% at 30 weeks to
69.0% at 36 weeks. Of the 6,587 livebirths outside a level-3 centre, 808 (12.3%)
were transferred within the first 3 days after birth by NETS to a level-3 centre,
the proportions falling with increasing maturity, being 73.7%, 48.5%, 28.4%,
26.9%, 18.8%, 11.8%, and 7.0% at 30, 31, 32, 33, 34, 35, and 36 weeks,
respectively. These data may help medical practitioners when determining the
place of delivery for infants 30-36 weeks' gestation.
PMID- 9761158
TI - Mid-trimester ultrasound diagnosis of isolated talipes equinovarus: accuracy and
outcome for infants.
AB - Seventeen fetuses were diagnosed with isolated congenital talipes equinovarus
(CTEV) on mid-trimester ultrasound at the Royal Women's Hospital, Melbourne,
between January, 1992 and December 1995. Sixteen of the 17 cases had an
amniocentesis performed and all karyotypes were normal. The remaining case was
phenotypically normal, except for a clubfoot. None of the pregnancies was
complicated by any of the recognized intrauterine environmental causes of CTEV.
Four of the babies were delivered prematurely and all survived the neonatal
period. Six (35%) infants did not have CTEV at birth, although 2 had postural
varus feet. Nine of the 11 infants who did have CTEV at birth were treated within
days of birth with plaster of Paris for periods of 6 to 12 weeks. Two infants
required no further treatment, 5 required orthotics and 2 required surgery. The
other 2 infants with CTEV at birth were treated with orthotics at 8 weeks of age.
All infants were considered to have an excellent result at the 2 year follow-up.
Seven (41%) of the prospective parents received antenatal counselling by an
orthopaedic surgeon and the lack of study on outcome following an ultrasound
diagnosis of CTEV was the impetus for our work.
PMID- 9761159
TI - Assessing the teratogenic potential of angiotensin-converting enzyme inhibitors
in pregnancy.
AB - To assess the teratogenic potential of angiotensin-converting enzyme (ACE)
inhibitors, we report on 20 prospective pregnancies and 85 identified from
articles in the literature. The anomaly rate was 20.6% in small series <10
entrants (95% CI 8.7-37.9%) and 1.4% in larger series > or =10 entrants (95% CI
0.03-7.3%) p=0.0016. The most consistent anomaly seen, skull hypoplasia, along
with renal dysfunction appear to be more related to prolonged or late pregnancy
exposure than to first trimester exposure. There is little supportive evidence
that ACE inhibitors (captopril or enalapril) are teratogenic. There seems to be
no absolute reason to discontinue these 2 medications prior to pregnancy, nor to
create anxiety when a patient is identified with the combination of early
pregnancy and treatment with these medications. There appears to be reason to
discontinue the medication in pregnancy but the adverse event rate cannot be
assessed because of inadequate prospective information.
PMID- 9761160
TI - Five successful deliveries following 9 consecutive spontaneous abortions in a
patient with Wilson disease.
PMID- 9761161
TI - Is it better to avoid urethral catheterization at hysterectomy and caesarean
section?
AB - This study involved 329 patients who had either a Caesarean section or a
hysterectomy. A comparison has been made between 70 patients who were never
catheterized and 251 who had a urethral catheter perioperatively. The absence of
recognized urinary tract infections in those without a catheter was significant
when compared with the 21 urinary infections identified in the catheterized group
(p<0.05). The absence of urinary tract infections in the uncatheterized group
clearly demonstrates the benefit of avoiding catheterization when possible.
PMID- 9761162
TI - Nonfreeing of the lower leaf of the rectus sheath at caesarean section: a
randomized controlled trial.
PMID- 9761163
TI - Transvaginal sacrospinous colpopexy for posthysterectomy vault prolapse.
AB - This study assesses the results of transvaginal sacrospinous colpopexy in the
treatment of posthysterectomy vault prolapse; 114 of 135 women were available for
follow-up between 8 months and 5 years after surgery. There was an initial
overall satisfaction rate of approximately 90% and this was maintained at 80%
even beyond 4 years. Those initially complaining of a lump or a swelling were
relieved of the symptom in almost 90% of cases. Those with a drag or ache were
cured in approximately 80% of cases. There was greatly improved bowel function in
approximately 60% of patients and in approximately 60% there was cure of stress
incontinence with additional buttressing sutures. Frequency and/or urgency was
relieved in over 50% of the group and there was more comfortable intercourse in
approximately 35% of those in whom this was a problem initially. As in previous
series, subsequent prolapse is more likely to be in the anterior vaginal wall and
there was an approximately 5% risk of this occurring over this period of follow
up. The variation in technique in this series in which nonabsorbable Ethibond
sutures were used to secure the vaginal vault to the sacrospinous ligament,
appears to provide better long-term vault support than previous reports in the
literature, without altering morbidity. Continuing follow-up will be required to
confirm that this will prove to be so in the longer term. This series therefore
confirms that the operation produces long-term support of the vaginal vault with
preservation of a functional vagina, and has a satisfactory success rate in the
relief of bladder and bowel symptoms associated with vault prolapse. However, it
also demonstrates that in this mostly aged group of patients there will be a
significant minority with limited relief of symptoms. It is important therefore
that appropriate preoperative counselling is carried out so that patients have
realistic expectations regarding the medium and long-term results of this
procedure.
PMID- 9761164
TI - Uterovaginal prolapse associated with rectal prolapse.
AB - A case of combined genital prolapse and rectal prolapse in a 55-year-old
multipara is reported. The mixed prolapse was treated by vaginal hysterectomy
with pelvic floor repair and laparoscopic rectopexy at the same sitting. The
feasibility of combined treatment of genital prolapse by the vaginal route and of
rectal prolapse by laparoscopic rectopexy is emphasized.
PMID- 9761165
TI - Uterus didelphys, a rare cause for tubal sterilization failure.
AB - Uterus didelphys is a rare congenital anomaly. It can result in a variety of
misadventures even in the hands of an expert. The present case reports uterus
didelphys as the cause for tubal sterilization failure. This is the first case of
this type seen in our institution in 35 years.
PMID- 9761166
TI - Massive mature solid teratoma of the ovary with gliomatosis peritonei.
AB - Glial implants on peritoneum and omentum may occur with mature solid teratoma of
the ovary (gliomatosis peritonei). The case of a 17-year-old girl is presented,
who had a massive solid ovarian teratoma with glial implants on visceral
peritoneum and omentum. The massive size of the tumour posed difficulty in
diagnosis. CT demonstrated a large teratoma. At laparotomy, the seedlings were
initially thought to be evidence of malignancy and hysterectomy was offered which
was refused by the parents. Oophorectomy was performed and the benign nature of
the tumour and implants was seen on histopathology. It is important to recognize
the benign nature of glial seedlings in such cases to avoid unnecessary extensive
surgery.
PMID- 9761167
TI - Ovarian dermoid cyst leakage--a cautionary tale.
AB - This case illustrates that when a dermoid cyst is punctured, an immediate
operative laparoscopy or laparotomy should be performed, along with lavage, to
avoid the problems associated with dermoid cyst contents spillage.
PMID- 9761168
TI - A casemix cost comparison of 2 treatments for ectopic pregnancy.
AB - In this paper a retrospective cost comparison between laparoscopic treatment of
ectopic pregnancy and conventional laparotomy under casemix funding has been
performed. The total mean cost of laparoscopic treatment was $2,930 while the
total mean cost of laparotomy was $4,259 per patient.
PMID- 9761169
TI - The use of reproductive health services by young women in Australia.
AB - Retrospective analysis of clinical data from 8 State/Territory Family Planning
Organizations (FPO) was conducted to determine the reproductive health services
used by young women. Between July, 1996 and June, 1997, a total of 185, 879
client visits were recorded at FPO clinics, of which 72,303 (39%) were by young
clients. The results showed that young women tended to use a combined oral pill,
postcoital pill and spermicides more than those older than 25 years (p<0.05).
Young women were also more likely to use services for management of sexually
transmitted disease (STD), counselling for HIV, STD and sexual assault (p<0.05).
However, there were considerable differences among the 3 groups of women:
Aboriginal clients, those who did not speak English at home, and those who were
born outside Australia. This study confirms that young women are using FPO
services especially for emergency/postcoital contraception, STD screening and
counselling. FPOs need to continue their existing role of providing reproductive
and sexual health services catering to the need of this special segment of the
population.
PMID- 9761170
TI - Total parenteral nutrition (TPN) and steroid usage in the management of
hyperemesis gravidarum.
PMID- 9761171
TI - Cord entanglement in monochorionic diamniotic twins.
PMID- 9761172
TI - Sacculation and retroversion of the gravid uterus in the third trimester.
PMID- 9761173
TI - Primary genital non-Hodgkin lymphoma.
AB - Although genital lymphoma either being an initial manifestation of occult nodal
disease or secondary involvement is not uncommon, extranodal lymphoma originating
primarily from the genitalia is quite rare. Here, we report a new case of primary
genital lymphoma involving the uterus and ovaries, but not the Fallopian tubes.
We also wish to emphasize that misdiagnosis of genital lymphoma, either
clinically or histologically can occur.
PMID- 9761174
TI - Re: The sign of stress incontinence--should we believe what we see?
PMID- 9761175
TI - Re: Transvaginal sacrospinous colpopexy--a new and easier way.
PMID- 9761176
TI - Use of the Shutt punch for transvaginal sacrospinous colpopexy.
PMID- 9761177
TI - Re: Transvaginal sonography of the endometrium in south Indian postmenopausal
women.
PMID- 9761178
TI - Re: Bleeding associated with vaginal hysterectomy.
PMID- 9761179
TI - Re: The debate regarding the risks of tocolytic agents.
PMID- 9761180
TI - Re: Bleeding associated with vaginal hysterectomy.
PMID- 9761181
TI - Molecular imprint polymers as highly selective stationary phases for open tubular
liquid chromatography and capillary electrochromatography.
AB - Chiral separations employing molecular imprint polymer (MIP) stationary phases in
both open tubular liquid chromatography (OT-LC) and capillary
electrochromatography (OT-CEC) are demonstrated. MIPs are highly crosslinked
polymers containing spatial and functionality memory of template molecules which
provide a higher degree of selectivity when used as stationary phases for
chromatographic separations. Thin films of molecular imprinted polymers bonded to
the inner walls of 25 microm ID fused-silica capillaries were prepared using an
in situ polymerization technique developed in our laboratory that allows the use
of conventional fused-silica capillaries with polyimide outer coatings. The
success rate in preparing such open tubular columns was about 70%. Methacrylic
acid and 2-vinyl pyridine were chosen as functional monomers, and either ethylene
dimethacrylate or trimethylol propane trimethacrylate was used as the
crosslinker. Toluene was employed as the porogen. Effects of polymerization
conditions on column preparation and chromatographic performance were studied.
Enantiomeric separations of D- and L-dansyl phenylalanines were achieved in both
OT-LC and OT-CEC modes with good selectivity and efficiencies. Both types of
separations may be performed on the same column using a single commercial
instrument.
PMID- 9761182
TI - Capillary electrochromatography of derivatized mono- and oligosaccharides.
AB - An octadecyl-silica (ODS) stationary phase with light surface coverage of
octadecyl ligands was introduced for capillary electrochromatography (CEC) at
moderate electroosmotic flow (EOF) velocity. The ODS stationary phase was
intentionally produced with light surface coverage in order to ensure a moderate
EOF velocity across the packed capillary column, thus allowing relatively rapid
analysis time. Despite the fact that the stationary phase leaves 75% of the
surface silanols unreacted, fused-silica capillary columns packed with this ODS
stationary phase exhibited reversed-phase behavior toward neutral alkylbenzene
homologous solutes using hydroorganic eluents. Closely related p
nitrophenylglycosides including some p-nitrophenyl-monosaccharides and p
nitrophenyl-maltooligosaccharides were readily separated on the ODS capillary
column within a relatively short analysis time. Also, alpha- and beta-anomers of
some p-nitrophenyl-monosaccharides were readily separated in the presence of a
small amount of borate buffer in the hydroorganic eluent.
PMID- 9761183
TI - Capillary electrochromatography with novel stationary phases. I. Preparation and
characterization of octadecylsulfonated silica.
AB - A novel silica-based stationary phase was developed for use in capillary
electrochromatography (CEC) at relatively high electroosmotic flow (EOF). The
silica was first bonded with a relatively hydrophilic layer bearing strong
sulfonic acid groups. To this charged polar sublayer, octadecyl functions were
covalently attached to yield the nonpolar top layer. This novel stationary phase,
referred to as octadecylsulfonated silica (ODSS), was packed in bare fused-silica
capillaries or in capillaries with the same coating as the sublayer on the silica
based stationary phase. The resulting packed columns were evaluated in CEC using
alkylbenzenes as the test model solutes. Good separations can be achieved in less
than 8 min, much faster than when using a regular octadecyl silica capillary
column. Due to the permanent negative charge provided by the sulfonated sublayer
on both the capillary walls and the silica particles, the magnitude of the EOF
remained more or less constant over a wide range of pH, and its magnitude can be
conveniently varied by the applied voltage.
PMID- 9761184
TI - Method development in pharmaceutical analysis employing capillary
electrochromatography.
AB - Capillary electrochromatography (CEC) has been employed to explore method
development for a series of structurally related polar neutral compounds of
pharmaceutical relevance. Capillaries with dimensions of 75 microm ID x 25 cm
length (34.5 cm total) were packed with Spherisorb ODS-1, Hypersil phenyl, and
Hypersil MOS (all 3 microm particles) and were compared in the reversed-phase
mode in order to determine which phase provided the best initial performance and
thus serve as the phase of choice for additional method development experiments.
The various separation parameters examined for their effect on efficiency, k',
resolution, and linear velocity included percent and type of organic modifier,
buffer concentration, voltage, and temperature. All separations were conducted
with an acidic mobile phase (aqueous mobile phase component, pH 3.0). The
separation efficiencies obtained were on the order of 200,000-260,000 plates/m,
which equates to reduced plate heights of 1.22 for columns packed with Spherisorb
ODS-1. Repeatable column-to-column separation performance was demonstrated.
PMID- 9761185
TI - Micellar electrokinetic chromatography: a convenient alternative to colorimetric
and high performance liquid chromatographic detection to monitor protease
activity.
AB - High performance capillary electrophoresis (HPCE) has been exploited as an
analytical method alternative to current procedures for the determination of
proteolytic activity of elastases from different sources. Due to some drawbacks
with capillary zone electrophoresis (CZE), the mode of operation employed for the
assay of elastolytic activity was micellar electrokinetic chromatography (MEKC).
Using a background electrolyte consisting of 35 mM sodium tetraborate, pH 9.3,
containing 65 mM SDS and 15% v/v methanol, separation of intact peptide substrate
from products of proteolytic reaction was easily achieved in a fused-silica
capillary of 50 cm effective length x 75 microm ID. This allowed us to determine
the rate of hydrolysis of substrates and to calculate the kinetic parameters Km
and k(cat) of the proteases investigated. A comparison of these data with those
obtained from high performance liquid chromatography (HPLC)-based experiments
showed that MEKC is a convenient technique for studying protease kinetics.
PMID- 9761186
TI - Development of separation systems for polynuclear aromatic hydrocarbon
environmental contaminants using micellar electrokinetic chromatography with
molecular micelles and free zone electrophoresis.
AB - Of four systems available from the literature, based on cyclodextrins,
dioctylsulfosuccinate, bile salts, and molecular micelles consisting of oligomers
of undecylenic acid, the most successful separation system in our hands is based
on the molecular micelles, oligomers of sodium undecylenic acid (OSUA). We have
employed organic additives of acetonitrile, acetone, and tetrahydrofuran in
achieving separations of polyaromatic hydrocarbons (PNAs) using molecular
micelles. Generally, successful separations are achieved with 20-40% composition
as the organic additive in an 8 mM borate buffer. We separated 16 PNAs with 20%
tetrahydrofuran in a system of 8 mM borate and 0.125 g/10 mL (ca. 6.25 mM) of
OSUA. Typical extracts of environmental samples contain additional analytes
besides the typical 16 target compounds. Among these are the nitrogen-containing
aromatics that can act as cations under conditions of low pH and additional
compounds that can act as anions under basic conditions in free-zone
electrophoresis. These additional classes of analytes are separated by capillary
zone electrophoresis/laser-induced fluorescence detection using a frequency
doubled laser operated at 257 nm.
PMID- 9761187
TI - Capillary electrophoresis chiral separations of basic compounds using cationic
cyclodextrin.
AB - Chiral separations of basic enantiomers were carried out by using a cationic
cyclodextrin (CD), quaternary ammonium beta-cyclodextrin (QA-beta-CD), under
counter-electroosmotic flow (counter-EOF) conditions. The special characteristics
of using a cationic CD to separate cationic enantiomers is that the EOF can be
reversed and the analyte-CD complexation is reduced. This is especially useful
for chiral separation of cationic compounds, which strongly bind with neutral and
anionic CDs (such as tricyclic amine compounds). The reduction in the binding
constants between the CD and the cationic enantiomers makes it easier to control
the optimum CD concentration. The application of the cationic CD also eliminated
the peak tailing problem caused by electrodispersion. The effect of pH and the
concentration of QA-betaCD on chiral separation has been studied. At pH 3.02, no
separation for any of the enantiomeric amines was observed. At pH 8.20, chiral
separation of some tricyclic compounds was achieved at very high resolution due
to the counter-EOF setup. At pH 11.6, most enantiomers were neutral and chiral
separation of some bicyclic compounds can be obtained.
PMID- 9761188
TI - Capillary electrophoresis, nuclear magnetic resonance and mass spectrometry
studies of opposite chiral recognition of chlorpheniramine enantiomers with
various cyclodextrins.
AB - Markedly different chiral separation abilities were observed for native beta
cyclodextrin (beta-CD), carboxymethyl-beta-CD (CM-beta-CD) and heptakis (2,3,6
tri-O-methyl)-beta-CD (TM-beta-CD) towards the enantiomers of (+/-)
chlorpheniramine ((+/-)-CHL) in capillary electrophoresis (CE). Native beta-CD
afforded almost baseline enantioseparation at a concentration of 18 mg/mL,
whereas only 1 mg/mL solution of CM-beta-CD was required for adequate
enantioseparation. TM-beta-CD allowed the nearly baseline enantioseparation only
at a concentration as high as 80 mg/mL. Moreover, the migration order of (+/-)
CHL in the presence of TM-beta-CD was opposite to that with beta-CD and CM-beta
CD. 1H and 13C-NMR spectroscopy and electrospray ionization mass spectrometry
(ESI-MS) have been used in order to obtain preliminary information about the
stoichiometry and the binding constants in the intermolecular diastereomeric
complexes of (+/-)-CHL with these CDs.
PMID- 9761189
TI - Chiral separation of alpha-amino acids by ligand-exchange capillary
electrophoresis using N-(2-hydroxy-octyl)-L-4-hydroxyproline as a selector.
AB - The direct chiral resolution of underivatized alpha-amino acids by capillary zone
electrophoresis (CZE) based on the principle of ligand exchange is described. An
N-(2-hydroxyoctyl)-L-4-hydroxyproline/Cu(II) complex was used as a chiral
selector. Besides amino acids containing aromatic residues, the basic amino acid
histidine was resolved. Baseline separations were obtained for all amino acids
investigated. The influence of selector concentration, electrolyte composition
and pH on the resolution was investigated. It was found that there is a
correlation between pI of the amino acids and the optimal pH.
PMID- 9761190
TI - Chiral separation of polychlorinated biphenyls by micellar electrokinetic
chromatography with sodium cholate.
AB - Micellar electrokinetic chromatography (MEKC) with one kind of bile salt (sodium
cholate) was used to separate three chiral polychlorinated biphenyls (PCBs; 84,
95, and 176), each one in its two enantiomers. Sodium cholate was used as chiral
surfactant in a 2-(N-cyclohexylamino) ethanesulfonic acid (CHES) buffer under
alkaline (pH 10) conditions containing urea (2 M). The influence of bile salt
concentration on the efficiency and the resolution between the two enantiomers of
PCBs 84 and 95 was established. The chiral separation of three PCBs was
successfully achieved in less than 30 min (approximately 23 min for PCB 176 and
approximately 29 min for PCBs 84 and 95).
PMID- 9761191
TI - Application of heparin to chiral separations of antihistamines by capillary
electrophoresis.
AB - A study of the chiral separations of antihistamines, including pheniramine,
chlorpheniramine, brompheniramine, carbinoxamine and doxylamine in capillary
electrophoresis (CE) was accomplished using heparin as a chiral additive (CA) and
phosphate buffer as the background electrolyte. Several factors were shown to
affect both the selectivity and the migration time, including concentration of
heparin, concentration of buffer, and the pH. A dual mechanism involving both
inclusion complexation and ionic interactions with heparin is thought to be
responsible for the chiral recognition. In the pH range of 2.6-3.5 and reversed
polarity, baseline resolutions were obtained using a wide range of buffer and
heparin concentrations. Typically, chiral resolution was obtained within 50 min.
PMID- 9761192
TI - Separation of neutral compounds by capillary electrokinetic chromatography using
polyethyleneimine as replaceable cationic pseudostationary phase.
AB - Polyethyleneimine (PEI, molecular weight 6 x 10(5) - 1 x 10(6)) is applied as a
positively charged pseudostationary phase for electrokinetic chromatography (EKC)
of uncharged mono- and oligophenols. EKC is carried out in PEI-coated fused
silica capillaries (with electroosmotic flow directed towards the anode) in 2-(N
morpholino)ethanesulfonic acid (MES) buffer (pH 7.0, 20 mM) with PEI added to the
solution in concentrations up to 0.70% w/v. The pseudostationary phase leads to a
retardation of the solutes mainly according to the number (and the position) of
the OH-groups of the separands, and is not influenced significantly by methyl
groups. For 0.70% w/v PEI solution, for instance, the relative retention, rho,
has values between 0.33 and 0.53. For the systems with the highest resolution of
the separands (0.25-0.30% PEI) 190,000 plates per meter are observed. The results
indicate that the separation selectivity is mainly caused by ion-dipole
interactions between the OH-groups of the solutes and the pseudostationary phase.
PMID- 9761193
TI - Use of scavenger beads to remove excess labeling reagents from capillary zone
electrophoresis samples.
AB - In many cases, samples for capillary zone electrophoresis (CZE) are derivatized
with a chromophore or fluorophore to enhance their detectability. To ensure
efficient labeling, a large excess of labeling agent is often used, which leads
to the presence of a large peak for unreacted reagent. Here we report that excess
reagent can be reacted with "scavenger beads" carrying an appropriate functional
group to remove it from the sample solution. We present examples of removal of
aminonaphthalene mono-, di-, and trisulfonic acid from mixtures in which they
were used to label mono- or oligosaccharides by reductive amination. Aldehyde
containing scavenger beads were made by oxidizing Sephadex G-50 beads with sodium
periodate. These were added to the labeling reaction mixtures after the reductive
amination of the sugars was complete. Almost complete elimination of the peak
from the labeling agent could be achieved.
PMID- 9761195
TI - Capillary electrophoresis of arsenic compounds with indirect fluorescence
detection.
AB - A capillary electrophoresis (CE)-indirect fluorescence detection method for
arsenic compounds is described. The five arsenic species, viz., arsenite
(As(III)), arsenate (As(V)), monomethylarsonate (MMA), dimethylarsinate (DMA) and
phenylarsonate (PhA), were efficiently separated by CE in 8 min with an 1.5 mM
fluorescein solution at pH 9.8. Fluorescein also functioned as a background
fluorophore for the indirect detection of these nonfluorescent arsenic species.
Linearity (r> or =0.996) of more than two orders of magnitude was generally
obtained. The relative standard deviation (RSD) values were in the ranges 0.4
0.7% and 2.2-8.2% for migration times and peak areas, respectively. The
concentration limits of detection (CLODs) for the arsenic compounds studied were
between 0.04 and 0.16 microg/mL (as arsenic). The detection sensitivity was
generally dependent upon the transfer ratio (TR, defined as the number of moles
of fluorescein ions displaced by one mole of analyte ions) of each arsenic
species. The applicability of the method for the analysis of ground water was
examined.
PMID- 9761194
TI - Capillary electrophoresis of anions at high salt concentrations.
AB - It is commonly thought that even a moderately high ionic concentration in the
background electrolyte (BGE) would lead to Joule heating and serious peak
distortion. However, we obtained very satisfactory separations of both inorganic
and organic anions in electrolyte solutions as high as 5 M sodium chloride using
direct photometric detection. Samples containing a 0.5 M concentration of a salt
can be analyzed directly by making the BGE concentration of the same salt even
higher to obtain electrostacking. The temperature in the center of the capillary
was calculated to be 49 degrees C when the current is at its maximum of 280
microA. The effect of various salts on electrophoretic and electroosmotic
mobility is discussed. Several examples are given of capillary electrophoresis
under high-salt conditions.
PMID- 9761196
TI - Characterization of micelles by capillary electrophoresis.
AB - A practical approach for the characterization of pure micelles, and binary or
ternary mixed micelles by capillary electrophoretic methods is presented.
Interest is focused on the determination of mobility and composition of the
micelles. The investigations are performed with bile salts, phosphatidylcholines
and fatty acids. Pure bile salt micelles are characterized with the help of
marking and displacement methods. Binary bile salt/phospholipid and ternary bile
salt/phospholipid/fatty acid micelles are analyzed using capillary
electrophoresis (CE) techniques with standard and improved UV detection, laser
induced fluorescence and electrospray ionization-mass spectrometry (ESI-MS). For
both the binary and the ternary systems, only one stable mixed micellar phase is
found with a high negative mobility.
PMID- 9761197
TI - The effect of blob size and network dynamics on the size-based separation of
polystyrenesulfonates by capillary electrophoresis in the presence of entangled
polymer solutions.
AB - This work focuses on the separation of standard polystyrenesulfonates (PSS), with
molecular masses (Mr) between 16 and 990 x 10(3) in capillaries filled with
semidilute (entangled) linear hydrophilic polymers. Contrary to cross-linked
chemical gels, which produce permanent networks, solutions of linear polymers
lead to dynamic networks. The analytical performances and migration mechanisms
are discussed on the basis of experiments performed in solutions of linear
polyethyleneoxides and derivatized celluloses of various molecular masses. The
influence of the mesh size and of the lifetime of the obstacles of the separating
network has been investigated in detail. The mesh size is assimilated to the blob
size of the separating polymer and is a decreasing function of its concentration.
The lifetime of the obstacles of the network, identified with the reptation time
of the polymer chain, characterizes its dynamics. This characteristic time
increases with both the molecular weight of the separating polymer and its
concentration. Its impact was first examined at fixed blob size. Then, the
influence of the blob size was studied while keeping the reptation time of the
network constant. By doing so, the existence of interactions between the solute
and the separating polymer or between the solute and capillary wall can be more
safely assessed. It appears that the reptation time of the mesh has a large
influence on the electrophoretic mobility of the PSSs under a threshold value,
which is of the order of magnitude of the time taken by the PSS to migrate on the
blob size. Also shown are separations using networks made up with mixtures of
polyethyleneoxides of the same nature and same mass concentration, but of very
different molecular masses. This latter approach allows one to adapt the
viscosity of the solution and the dynamics of the network, keeping the blob size
constant.
PMID- 9761198
TI - Analysis of antisense oligonucleotides by on-capillary isotachophoresis and
capillary polymer sieving electrophoresis.
AB - An attempt was made to evaluate the stability of an antisense oligonucleotide
against nucleases present in HBL 100ras cells. To detect nanomolar concentrations
of the oligonucleotide, a sensitive detection system was required. A combination
of capillary electrophoresis/laser-induced fluorescence (CE-LIF) with
fluorescence derivatization did not improve the sensitivity significantly and
also resulted in loss of separation of the derivatized sample. On-column
isotachophoresis for the preconcentration of oligonucleotide samples in DB-17
coated capillaries filled with hydroxyethyl cellulose solution could be an
alternative. The isotachophoresis (ITP) step allows injection of up to 40% of the
capillary volume without loss in peak resolution and peak efficiency. Using ITP
capillary polymer sieving electrophoresis (CPSE), the limit of quantitation at a
signal-to-noise ratio of 10 was 73 ng/mL for a 12-mer oligonucleotide. Using
these conditions, the gain in sensitivity was 125.
PMID- 9761199
TI - Subnanomolar detection limit for sodium dodecyl sulfate-capillary gel
electrophoresis using a fluorogenic, noncovalent dye.
AB - Picomolar limits of detection are obtained using the noncovalent, fluorogenic
dye, Sypro Red. The size separation of four commonly used sodium dodecyl sulfate
capillary gel electrophoresis (SDS-CGE) molecular weight markers with 8% linear
polyacrylamide (PAA) as the sieving matrix is used to construct a calibration
curve for molecular weight determinations. SDS-CGE purity and molecular weight
determination of purified chorismate mutase-prephenate dehydrogenase (CMPD) from
Escherichia coli is shown to be comparable in accuracy with slab gel SDS
polyacrylamide gel electrophoresis (SDS-PAGE). A migration time precision study
indicates excellent reproducibility. Sypro red labeling of SDS-bovine serum
albumin (SDS-BSA) complexes at nanomolar protein concentrations suggests assay
detection limits surpassing those of silver staining. This detectability exceeds
that achieved in previous SDS-CGE laser-induced fluorescence studies. This
approach is expected to be easily adapted for use with commercial polymer
formulations and automated instrumentation.
PMID- 9761200
TI - Sodium dodecyl sulfate-capillary electrophoresis of proteins in a sieving matrix
utilizing two-spectral channel laser-induced fluorescence detection.
AB - We report a method for protein labeling, separation by capillary electrophoresis
in a polymer sieving matrix, and detection by laser-induced fluorescence.
Different dyes are used to label standard and sample proteins. A two-spectral
channel detector resolves fluorescence from the sample and standards. Comparison
of the migration time of the sample and standards permits the precise
determination of molecular weight, irrespective of variations in run-to-run
migration times.
PMID- 9761201
TI - Nonaqueous capillary electrophoresis--its applicability in the analysis of food,
pharmaceuticals and biological fluids.
AB - The use of nonaqueous electrophoresis media for the application of capillary
electrophoresis in the analysis of food, pharmaceuticals and biological fluids is
reviewed. Some of the applications are discussed in detail and the benefits of
using nonaqueous media in these cases are outlined. Three new applications within
pharmaceutical analyses are presented. In these methods either a simple sample
pretreatment by dilution with methanol (determination of chlorhexidine in a
cream) or selective on-line capillary electrophoresis mass spectrometry (methods
for identification of seizure drugs or opium alkaloids) are used. The choice of
organic solvents and electrolytes for nonaqueous capillary electrophoresis are
discussed. Furthermore, validation data obtained using capillary electrophoresis
based on the nonaqueous principle are listed and discussed.
PMID- 9761202
TI - Nonaqueous capillary zone electrophoresis for separation of free fatty acids with
indirect fluorescence detection.
AB - The feasibility of combining nonaqueous capillary zone electrophoresis with
indirect fluorescence detection was studied for the efficient separation and
sensitive detection of ionizable hydrophobic substances which do not possess
practically suitable detection properties. Medium- and long-chain free fatty
acids, C6-C24, were selected as test compounds. The results showed that such a
wide range of medium- and long-chain free fatty acids could be separated between
any two consecutive homologs in one run and be detected at a level of about 0.01
0.02 mM in highly basic methanol/acetonitrile media containing fluorescein as
coion of background electrolyte for indirect fluorescence detection.
PMID- 9761203
TI - On-line capillary electrophoresis-electrospray ionization mass spectrometry using
a polymerized anionic surfactant.
AB - On-line capillary electrophoresis-electrospray ionization-mass spectrometry (CE
ESI-MS) has been used to determine the tricyclic antidepressant drugs
(imipramine, doxepin, and amitriptyline) as well as the beta-adrenergic blocker
drugs (propranolol and alprenolol). A CE-ESI-MS interface linking a manually
operated CE system and a Finnigan MAT-900 sector mass spectrometer (with an
Analytica electrospray ionization source) has been constructed in-house and
employed for this study. Although a water/methanol based capillary zone
electrophoresis (CZE) buffer was initially used to determine these analytes,
enhanced resolution was obtained by addition of a polymerized surfactant, i.e.,
poly-sodium undecylenic sulfate (poly-SUS), into the electrokinetic
chromatography (EKC) buffer. When a low concentration of this poly-SUS surfactant
was added to a volatile EKC buffer, these structurally similar cationic drugs
were EKC separated and on-line detected by ESI-MS.
PMID- 9761204
TI - Pressure-assisted and pressure-programmed capillary electrophoresis/electrospray
ionization time of flight-mass spectrometry for the analysis of peptide mixtures.
AB - Pressure assisting and pressure programming the inlet of the capillary
electrophoresis instrument were used for the analysis of peptide mixtures and
protein digests using capillary electrophoresis/electrospray ionization-mass
spectrometry (CE/ESI-MS). CE/ESI-MS of peptide mixtures and tryptic digests of
proteins was studied using three different types of capillary columns: (i) a
freshly aminopropylsilane (APS)-treated column, (ii) an untreated column, and
(iii) a degraded APS-treated column. To maintain a constant and adequate buffer
flow toward the CE capillary outlet for stable CE and ESI operation, low pressure
was applied to the inlet of the CE when an untreated or degraded APS capillary
was used. By programming the inlet pressure, CE/ESI-MS analysis time was reduced
to 1/3 of its original time. The utility of this technique is demonstrated by
CE/ESI-MS analysis of a hemoglobin variant (hemoglobin-S) and its tryptic
digests. Identification of the mutant peptide in the tryptic digest of hemoglobin
S was achieved by collision-induced dissociation (CID) of the protein digests
using CE/ESI time of flight-mass spectrometry (TOF-MS).
PMID- 9761205
TI - Enhanced sensitivity for sequence determination of major histocompatibility
complex class I peptides by membrane preconcentration-capillary electrophoresis
microspray-tandem mass spectrometry.
AB - Sequence analysis of antigenic major histocompatibility complex (MHC) class I
peptides requires minimizing sample loss and enhancing mass spectrometric
sensitivity. In order to facilitate such analyses, we have coupled on-line
membrane preconcentration-capillary electrophoresis (mPC-CE) with microspray mass
spectrometry (mPC-CE-microMS) and tandem mass spectrometry (mPC-CE-microMS/MS).
Specifically, cell lysate from approximately 10(9) EG-7 mouse tumor cells was
immunoprecipitated and the released MHC class I peptides were subjected to
reverse-phase HPLC. An HPLC fraction containing antigenic peptide(s) shown to
induce T-cell stimulation was subjected to mPC-CE-microMS. Approximately 10
microL (from 100 microL) of the fraction was pressure-injected and concentrated
on a styrenedivinylbenzene (SDB) impregnated membrane. The peptides were eluted
from the membrane with approximately 100 nL of 80% methanol, sandwiched between a
leading stacking buffer (LSB, also serving as CE separation medium) of
approximately 110 nL of 0.1% acetic acid in 10% methanol, and a trailing stacking
buffer (TSB) of approximately 110 nL of 0.1% NH4OH. On application of the CE
voltage the peptides are subjected to moving boundary transient isotachophoresis
and focused. The peptides were separated in a Polybrene-coated capillary with
application of -20 kV in reverse polarity mode and subsequently sprayed via an
emitter coupled to the CE capillary by a liquid junction containing a platinum
wire. An ion at m/z 482.3 was detected and subjected to mPC-CE-microMS/MS and
determined to be SIINFEKL, a peptide (OVA) known to be antigenic in the mouse
model system. Sensitivity enhancement over conventional mPC-CE-MS and MS/MS was
approximately 100-fold.
PMID- 9761206
TI - Capillary electrophoresis and capillary electrophoresis-electrospray-mass
spectroscopy for the analysis of heterocyclic amines.
AB - Fourteen heterocyclic amines (HAs) were analyzed by capillary electrophoresis
(CE) on a polyvinyl alcohol (PVA)-coated capillary column. The optimized
electrolyte is composed of 20 mM ammonium acetate, pH 3.0, and 20% methanol.
Similar conditions were applied in electrospray-mass spectrometry (CE-ES-MS). The
CE-ES-MS optimization procedure includes the position of the capillary in the
stainless steel interface, the flow of the sheath liquid and its composition.
PMID- 9761207
TI - Capillary electrophoresis interfaced to inductively coupled plasma mass
spectrometry for element selective detection in arsenic speciation.
AB - A method is presented to separate and detect six arsenic species by capillary
electrophoresis (CE) interfaced to inductively coupled plasma mass spectrometry
(ICP-MS). CE was used as a highly resolving separation system, whereas ICP-MS
served as an element selective detector providing low detection limits. The
special mode of operation included sample stacking and a differentiation of
separation and detection. This provided separation and detection of six As
species, uncharged and anionic, to be monitored within a single run. Detection
limits were calculated according to IUPAC recommendation at 15 microg As/L for As
(III), dimethyl arsinic acid (DA), monomethyl arsonic acid (MA) and As (V), or 65
microg As/L for arsenobetaine (AsB) and arsenocholine (AsC). Investigations were
focused on possibly occurring interferences, e.g., ArCl+ interference at the
monoisotope 75As. Finally, real samples from biomedical field (urine) and
environmental field (sewage sludge) were analyzed.
PMID- 9761208
TI - Electrochemical detection in capillary electrophoresis with dual-parallel on
capillary electrodes.
AB - A new approach for dual electrode electrochemical detection in capillary
electrophoresis (CEEC) is described. In this approach, two identical capillaries,
each containing an on-capillary electrode incorporated permanently onto its tip,
were paired together for simultaneous sample injection and detection. This
procedure permitted dual-parallel detection to be performed without the need for
painstaking alignment of the electrodes with respect to one another and to the
capillary outlet as is required for the off-capillary microelectrode systems
usually employed in CEEC. As a result, independent detection at two electrodes
held at different potentials or at two electrodes of different composition or
structure could be performed simply and with wide flexibility. Fabrication of on
capillary electrodes was carried out by sputter-coating the exit end of the
capillaries with a thin layer of Au or Pt. Dual electrode system performance was
demonstrated by separation and analysis of phenol and catechol samples. In
addition, the detection system was coupled with glucose oxidase for the selective
detection of glucose.
PMID- 9761209
TI - Fluorescence imaging of light absorption for axial-beam geometry in capillary
electrophoresis.
AB - A new method for investigation of axial-beam absorption detection for improved
detection limits in microcolumn separations is reported. The method is based on
fluorescence imaging of light absorption along a separation capillary. The
probing UV light is introduced at one end of the capillary and shows an
exponential fall-off along the capillary. As the UV light propagates through the
sample peaks, an additional loss in intensity will be observed. In order to view
the absorption profile along the capillary, a background fluorophore is added to
the buffer. A charge-coupled device (CCD) detector and imaging optics are placed
beside the capillary to view the capillary in a direction perpendicular to the
capillary. Signal integration is employed for consecutive exposures as well as
for neighboring detector pixels in order to increase the signal-to-noise ratio.
Measurements for stilbene 3 with sulforhodamine B as a background fluorophore are
presented. The characteristics of the detection method and potential improvements
are discussed.
PMID- 9761210
TI - A computer-controlled variable light attenuator for protection and autoranging of
a laser-induced fluorescence detector for capillary zone electrophoresis.
AB - Photodetectors have a limited range over which they can measure light intensities
for any particular setting. The intensity of light reaching the detector can be
kept within this range by using a liquid crystal variable light attenuator
controlled by a computer that continuously checks the amount of light reaching
the detector and adjusts the attenuation to an appropriate level. Using such a
system we have constructed an intensified charge-coupled device (ICCD) camera
based detector with a dynamic range of over six orders of magnitude which is
never exposed to damaging or saturating light levels.
PMID- 9761211
TI - Dual UV-absorbing background electrolytes for simultaneous separation and
detection of small cations and anions by capillary zone electrophoresis.
AB - The simultaneous separation and detection of small cations and anions by
capillary zone electrophoresis (CZE) with indirect ultraviolet (UV) detection was
successfully demonstrated in a background electrolyte (BGE) containing two UV
absorbing components. Benzylamine, imidazole, benzenesulfonic acid,
sulfosalicylic acid, and pyromellitic acid were tested as the components of the
BGE. The success of the simultaneous separation of the cations and anions is
dependent upon the proper selection of the electrolyte components and control of
the migration of the ions towards the detector. High pH is beneficial to the
detection of anionic analytes but not to the separation of cationic analytes
because of large electroosmotic flow produced under this condition. The upper pH
limit of the working pH range is confined by the pKa value of the cationic
component of the BGE. The influence of pH and total electrolyte concentration on
the electroosmatic flow (EOF) counteracted each other. This counteraction effect
imposes an upper limit on the change of total electrolyte concentration at
certain pH. It was found that the EOF should be larger by at least 10 x 10(-5)
cm2V(-1)s(-1) than the electrophoretic mobilities of the anions so that the
anions could be detected on the cathodic side within reasonable times and with
good peak shapes. In the imidazole-sulfosalicylic acid BGE, the detection limits
(signal to noise, S/N = 3) for the cations and anions ranged from 100 to 900 ppb.
In the benzylamine-pyromellitic acid BGE, K+, Na+, Li+, CH3 COO-, HPO4(2-), F-,
ClO3-, ClO4-, NO3-, NO2-, Cl- and SO4(2-) were separated within twelve minutes.
The strategies for selection of the electrolyte components of the binary BGE were
also discussed.
PMID- 9761212
TI - Capillary electrophoresis/laser-induced fluorescence detection of fluorescein as
a groundwater migration tracer.
AB - Capillary electrophoresis (CE) has been applied to the determination of the
groundwater migration tracer dye fluorescein based on laser-induced fluorescence
(LIF) detection and compared to determinations obtained with traditional
spectrofluorimetry. Detection limits of injected dye in the low parts per
trillion (ppt) ranges have been accomplished with both CE/LIF based on the Ar ion
laser and with a spectrofluorimeter. This approach was used for a real-world
problem in determining groundwater migration between adjacent Resource
Conservation and Recovery Act (RCRA) and Superfund sites by the Environmental
Sciences Division in response to regional needs and as application of new
analytical tools under development. Fluorescent dye was injected into source
wells and then was determined in monitoring wells by extracting pads that
adsorbed the dye or by directly determining the dye in the water using solid
phase extraction (SPE), a preconcentration technique. The approaches based on
CE/LIF exhibits increased specificity over existing approaches due to the
separation and unique migration time of the dye. Additional studies were aimed at
achieving sub-ppt levels in the water using solid-phase extraction and field
amplified injection techniques.
PMID- 9761213
TI - Factors influencing the choice of buffer in background electrolytes for indirect
detection of fast anions by capillary electrophoresis.
AB - The suitability of relatively slow (low absolute value of mobility) coanionic
buffers in background electrolytes (BGEs) for indirect photometric detection of
anions by capillary electrophoresis was investigated. As a model system, 2
(cyclohexylamino)ethanesulfonic acid (CHES) was used to buffer the indirect
detection electrolyte of sodium chromate. CHES (PKa 9.55) is a zwitterionic
molecule carrying a net negative charge depending on the pH (effective charge
0.5 at pH = pKa). Within its useful pH buffering range CHES acted as a competing
probe coanion. System peaks were induced which had deleterious effects on the
detection sensitivity of slow to medium mobility anions. The mobility of the
system peak was determined by the effective mobility of CHES, both of which
increased with increasing pH. The peaks of analytes that migrated near or on the
system peak were distorted and lost all quantitative properties. Analytes that
migrated after the system peak either were not detected or reversed their
responses. Analytes that migrated well before the system peak were unaffected.
Consequently, the suitability of slow coanionic buffers is limited either to (i)
fast anions or, (ii) a pH range much below the PKa, where the buffering capacity
is not optimal.
PMID- 9761214
TI - Capillary electrophoresis.
PMID- 9761215
TI - Evidence from urinary cortisol that maternal behavior is related to stress in
gorillas.
AB - By studying western lowland gorillas (Gorilla gorilla gorilla, n = 8) in
zoological gardens via ethological and non-invasive physiological techniques, we
have demonstrated that their postpartum maternal behavior is related negatively
to their postpartum urinary titers of cortisol. On the basis of this finding, it
is proposed that postpartum stress contributes to disrupted maternal behavior in
the gorilla in captivity. Morning urine samples were collected with a mean
sampling interval of 1.6 days from Day 14 prepartum to Day 14 postpartum (n = 11
pregnancies). Creatinine-indexed (Cr) urinary cortisol titers declined
significantly between Day 9 to 1 prepartum (0.634 +/- 0.014 microg/mg of Cr, mean
+/- SEM) and Day 1 to 6 postpartum (0.396 +/- 0.030 microg/mg of Cr, mean +/-
SEM; p < 0.01-0.001). For each pregnancy, the relative postpartum decline in
urinary cortisol was calculated as (microg of cortisol/mg of Cr Day 1 to
4)/(microg of cortisol/mg of Cr Day -4 to -1). Values ranged from 0.35 to 1.12,
were independent of absolute prepartum cortisol titers, and were interpreted as
evidence of inter-female differences in postpartum hypothalamo-pituitary-adrenal
axis activity and, therefore, postpartum stress. This postpartum stress index was
negatively correlated with the amount of time (0-100%) that females carried and
supported their 0-14 day-old infants in a ventral position during locomotion
(r(s) = -0.68, p < 0.05) and tended to be negatively correlated with the total
amount of time (0-100%) they spent in ventro-ventral contact with their infants
(r(s) = -0.58; p < 0.10). This study provides the first physiological evidence
that postpartum stress is an important etiologic factor in gorilla maternal
failure in captive environments.
PMID- 9761216
TI - Effect of prenatal stress on plasma corticosterone and catecholamines in response
to footshock in rats.
AB - The effect of prenatal stress was investigated on the sympathoadrenal response to
novelty and footshock by measuring the time course of the changes in circulating
corticosterone (COR) catecholamines and their metabolites. Pregnant rats were
subjected to noise and light stress, three times weekly on an unpredictable basis
throughout gestation. When the male offspring of stressed rats (PS) and those of
unstressed mothers (C) were 4.5-5 months of age, they were prepared with
indwelling catheters in the tail artery 24 h before the experiment. Resting
levels of plasma COR, noradrenaline (NA), adrenaline (AD), dihydroxyphenylglycol
(DHPG), dihydroxyphenylacetic acid (DOPAC), and dihydroxyphenylalanine (DOPA)
were measured. Further blood samples were taken within 3 min of their transfer to
the shock box, 1-2, 5, 15, and 45 min after footshock. Plasma COR was
significantly higher in PS than in C rats at rest, but those of adrenaline, NA,
and their metabolites did not differ in the two groups. Transfer of the rats to
the shock box increased plasma COR, NA, adrenaline, and dihydroxyphenylglycol in
both groups, and dihydroxyphenylalanine and dihydroxyphenylacetic acid only in PS
rats. All the catechols increased further 2-3 min after footshock, except
dihydroxyphenylalanine in PS rats. Plasma NA and dihydroxyphenylglycol levels
were significantly higher in PS than in C rats immediately after footshock,
indicating a greater activation of the sympathetic nervous system in PS rats. The
findings demonstrate for the first time that prenatal stress can induce long term
changes in the sensitivity of the sympathoadrenal system to stress.
PMID- 9761217
TI - Effect of American ginseng (Panax quinquefolium) on male copulatory behavior in
the rat.
AB - The effects of American ginseng (Panax quinquefolium) on male rat copulatory
behavior were investigated. Adult Sprague-Dawley rats were administered either
10, 50 or 100 mg/kg of Panax quinquefolium or a sesame oil vehicle per os (p.o.)
for 28 days and copulatory behavior parameters were measured. Ginseng-treated
male rats demonstrated a significant decrease in mount, intromission and
ejaculation latencies compared to vehicle controls. Hormone analyses revealed no
difference in plasma luteinizing hormone or testosterone levels between ginseng-
and vehicle-treated animals; however, plasma prolactin levels were significantly
reduced by all doses of ginseng tested. When male rats were treated with the 100
mg/kg dose of ginseng for 1, 14 or 28 days, mount and intromission latencies were
significantly reduced at 14 and 28 days of daily ginseng treatment, whereas
ejaculation latency was significantly reduced after 1 day of ginseng treatment
when compared to vehicle controls. Plasma prolactin levels were also
significantly decreased after 14 and 28 days of daily ginseng administration.
There were no differences in body weight or in testes, seminal vesicle, anterior
pituitary or spleen weights between ginseng- and vehicle-treated rats. These
results demonstrate that P. quinquefolium significantly facilitates male
copulatory behavior. The reduction in plasma prolactin levels suggests that
ginseng-induced alterations in dopaminergic neurotransmission may play a role in
the ability of P. quinquefolium to stimulate copulatory behavior in the male rat.
PMID- 9761218
TI - Intestinal fat suppressed intake of fat longer than intestinal sucrose.
AB - Although animals eventually stop eating when only experiencing the oro-sensory
stimuli from a food, they stop eating much more rapidly if they also receive
postgastric stimuli simultaneously. This suggests that the postgastric effects of
a nutrient influence the hedonic value of food or motivation to consume that
food, and thus, can influence food selection within the time frame of a meal. In
this experiment, rats were equipped with a gastric fistula and duodenal cannula.
This combination allowed them to receive the same oro-sensory stimuli, but
different postgastric nutrients. While ingesting either a fat (Intralipid) or
carbohydrate (sucrose) solution, both of which drained from the gastric fistula,
the rats received a duodenal infusion of either sucrose (10 mLs, 0.24 kcals/mL),
fat (10 mLs, 0.25 kcals/mL) or saline (10 mLs, 0 kcals/mL). While ingesting the
Intralipid, a duodenal infusion of fat suppressed intake quicker and longer than
an infusion of sucrose. While the animals ingested sucrose, sucrose and fat
suppressed intake equivalently.
PMID- 9761219
TI - Temporal dynamics of human masticatory sequences.
AB - Many motor behaviors produced by humans and other mammals are temporally
segmented. That is, sequences of rhythmic or repetitive behavior occur as a
series of brief, 2- to 4-s bouts separated from each other by pauses or posture
adjustments. Little is known about the physiological mechanisms underlying
temporal segmentation, although several hypotheses have been advanced.
Experimental and modeling studies are currently underway to gain insight into
this phenomenon. One of the problems hampering advancement is the lack of
relatively simple behavior models that can be studied in both humans and other
mammals. We have recently reported that temporal segmentation occurs in guinea
pig chewing sequences. Thus, it seems logical to explore whether temporal
segmentation occurs in human chewing sequences as well. Toward this end, the
current study evaluated the temporal dynamics of chewing sequences in humans.
Thirteen subjects were videotaped on campus eating areas during lunch-time. Inter
occlude intervals, i.e., time between maximum jaw closures, were calculated using
a custom computer program, which also recorded whether the interval represented a
chew or a pause in chewing. Chewing rate, pause durations, and chewing burst
durations, i.e., duration of continuous chewing uninterrupted by pauses, were
calculated. Median chewing burst duration for the sample was 2.91 s. This
corroborates other studies' findings of 3-s temporal segmentation in repetitive
movements. We conclude that automatic chewing sequences contain temporal
segmentation. Future work is required to gain insight into whether the
physiological mechanisms of this time-based phenomenon are similar among
different species.
PMID- 9761221
TI - Relationship of body energy status to inflammation-induced anorexia and weight
loss.
AB - The response to acute inflammation of rats at two levels of prior weight
reduction were compared with normal-weight rats to examine how prior alterations
in body energy status influence inflammation-induced anorexia and weight loss.
Specifically, body weights were either reduced by 6%, the level of weight loss
expected in normal-weight rats following induction of acute inflammation, or by
12%, a level 6% below that expected of the normal-weight rats. Rats were either
allowed to eat ad lib. on postinflammation Day 1 or were kept on food restriction
until Day 5, when anorexia was no longer expected to be present. As predicted,
normal-weight rats allowed to eat ad lib. beginning Day 1 displayed the most
severe anorexia. Total food intake of this group over the first 5 days following
inflammation induction was 33% less than the control (CON) group. Rats with 6%
prior weight reduction displayed a milder anorexia, eating only 15% less than the
CON group over the first 5 days. In contrast, rats with 12% prior weight
reduction ate the same amount of food as the CON group. Interestingly, similar
feeding patterns were observed in rats that resumed ad lib. feeding on Day 5. The
outcome of these various feeding patterns was to bring body weights of all the
inflammation groups to the same level, approximately 6% below CON group weights.
These results provide further evidence that proinflammatory mediators induce a
temporary reduction in the amount of body tissue (weight) spontaneously
maintained that is directly proportionate to the magnitude of insult.
PMID- 9761220
TI - Acute, early thermal experience alters weaning onset in rats.
AB - We hypothesized that first ingestion of solid food (weaning onset) would be
accelerated in young rats with advanced thermoregulatory development. To
manipulate the pups' thermoregulatory development, we exposed rat pups, but not
their dams, to a Cold (10 degrees C), Moderate (21 degrees C), or Warm (31
degrees C) ambience for 2 h/day from postnatal Day 2-14, expecting that early
exposure to cooler temperatures would accelerate development of thermoregulatory
capabilities and thus accelerate nest egression as well as onset of feeding.
Contrary to expectation, cold exposure was associated with a profile of
developmental delays in both growth and maturation. Pups in the Cold condition
began feeding later than pups with Moderate or Warm thermal experiences. We then
evaluated thermoregulatory status (mechanisms for heat production and temperature
conservation) on Day 15-16 (just prior to weaning onset). Thermogenesis, measured
by oxygen consumption, was unaltered by the thermal manipulation. In contrast,
pelage development (insulation) was altered. Pups in the Warm condition had
greater fur density and an increased frequency of longer hairs relative to pups
in the Cold condition. Although the developmental response to early cold exposure
was in the direction opposite to our predictions, the hypothesized relation of
thermoregulatory development to weaning onset was supported: Thermoregulatory
status correlated with weaning onset.
PMID- 9761222
TI - Increased flavor acceptance and preference conditioned by the postingestive
actions of glucose.
AB - In Experiment 1, rats were given daily 2-h access to chow and water and 20-h
access to flavored solutions (cherry or grape). On alternate days, one flavor
(CS+) was paired with intragastric infusions of 16% glucose and another flavor
(CS-) with IG water. In subsequent choice tests, the rats strongly preferred
(95%) the CS+ to the CS-. CS+ intake also greatly exceeded CS- intake during one
bottle training sessions (71 vs. 18 g/20 h). This increased acceptance was due to
both increased bout size and number. When CS+ was paired with IG water
(extinction test), CS+ bout size declined to CS- levels, while CS+ bout number
and total intake remained elevated. In Experiment 2, rats trained with sucrose
octa acetate and citric acid solutions also showed increased CS+ acceptance and
preference in one- and two-bottle tests, respectively. The rats also consumed
more CS+ than CS- during short-term (30 min/day) one-bottle tests and intraoral
intake tests under both deprived and ad lib. feeding conditions. These results
demonstrate that the postingestive actions of glucose can condition substantial
increases in flavor acceptance as well as flavor preference.
PMID- 9761223
TI - Evidence that oral and nutrient reinforcers differentially condition appetitive
and consummatory responses to flavors.
AB - Rats tend to increase their intake of a flavor that has previously been paired
with either sweet taste or with caloric repletion. However, it is unclear whether
such a change in intake is caused by changes in appetitive behaviors such as
orienting and approach, or changes in consummatory behaviors and oral
responsiveness. Also, it is unclear whether oral reinforcers (sweetness) and
postingestive reinforcers (nutrients) lead to the same kinds of behavioral
change. In the current experiments, weanling rats with oral and gastric cannulas
repeatedly experienced a flavor paired with either sweetness, high caloric
density, or neither. Rats were then tested for differences in appetitive
olfactory orienting and consummatory oral responsiveness elicited by the flavor.
Results suggest that oral reinforcement (sweetness) produces conditioning of
appetitive responding to the flavor, while postingestive reinforcement produces
conditioning of consummatory responding. A second experiment indicates that these
behavioral changes are specific increases in responsiveness conditioned by flavor
+ unconditioned stimulus (US) pairing, and are unlikely to be nonspecific effects
of daily unconditioned stimulus exposure.
PMID- 9761224
TI - Maltodextrin preloads reduce food intake without altering the appetiser effect.
AB - The effects of consumption of a soup preload with added maltodextrin, relative to
a no-maltodextrin control soup matched for sensory properties, on intake and the
pattern of changes in rated hunger and fullness during lunch were investigated in
24 male volunteers. Preloads were consumed 30 min before lunch and condition
order counterbalanced. Intake at lunch was reduced significantly by 77 g (407 kJ)
after the maltodextrin preload, and this reduced intake was associated with a
significant reduction in eating rate but not meal duration. Hunger ratings were
significantly lower, and fullness ratings significantly higher, at the start of
lunch after the maltodextrin compared with control preload. However, the pattern
of changes in subjective appetite once eating had started (assessed by analyzing
best-fit quadratic functions between rated appetite and actual intake) did not
differ between preloads. Neither the rated pleasantness of the lunch food at the
start of the test meal nor the pattern of change in pleasantness across the meal
differed between preloads. These results imply that the effect of maltodextrin
preloads on appetite is to reduce the general desire to eat, and possible
mechanisms for this effect are discussed.
PMID- 9761225
TI - Sustained stress disrupts the performance and acquisition of delayed alternation
in rats.
AB - The effects of sustained stress on acquisition and performance of a delayed
alternation task were studied in male rats. Rats lived 24 h per day in operant
cages where they earned all of their food via lever pressing. During the stress
portion of each experiment, one group of rats was able to avoid or escape
signaled intermittent footshock (Avoidance/Escape group), a second group (Yoked)
did not have control over shock termination, a third group never received shock
(Control). Shock trials were presented around-the-clock at approximately 5-min
intervals and the stress portion of each study lasted 1 week. We have previously
reported that rats tolerate this paradigm well and avoid/escape 99% of the shock
trials. Three experiments were conducted. In Experiment 1, rats learned the
delayed alternation task prior to stress onset; in Experiment 2, rats were
exposed to stress and the alternation task concurrently; in Experiment 3, rats
were stressed for 14 days prior to being required to perform the delayed
alternation task. In the first experiment, stress decreased both food intake and
the accuracy of responding during the first days of stress. In the second
experiment (acquisition), stressed rats required more days to reach asymptotic
performance on the alternation task. In Experiment 3, rats stressed for 14 days
prior to acquisition of the delayed alternation task performed similarly to
controls.
PMID- 9761226
TI - Age-related effects on reproductive function and sexual competition in the male
prosimian primate, Microcebus murinus.
AB - In the male lesser mouse lemur (Microcebus murinus), a polygamous long-day
breeder of which the life span may reach 12-14 years, the effects of aging on
socio-sexual relationships were studied on 44 captive animals of various ages. In
this primate, new dominance relationships must be established at the beginning of
each breeding season. During the breeding season induced by exposure to
artificial long days, preoestrous females were introduced into cages of paired
males to elicit sexual competition. Sexual behaviors, social interactions through
chemical signals, and dominance relationships were recorded in paired males
either of similar age (young or aged pairs), or of mixed ages. In all pairs,
competition for priority access to females always occurred and dominance
relationships were established unrelated to body weight. Although aged animals
exhibited significantly less number of sexual and aggressive behaviors, they
outranked younger males excepted when reaching oldest age. Independent of male's
age, the typical pattern of seasonal rhythm of testosterone was observed, but
aged males demonstrated a significant reduction in mean hormonal levels (25.5 +/-
2.8 ng/mL, n = 8) compared to young animals (50 +/- 2.7 ng/mL, n = 8). Moreover,
their hormonal response to photoperiod was phase-shifted leading to reduced
testosterone values when females entered oestrus. Despite the fact that
testosterone levels and sexual behaviors decreased with aging in this primate,
older males reached a dominant position, increasing thus their reproductive
success.
PMID- 9761227
TI - Assessing olfactory performance in an Old World primate, Macaca nemestrina.
AB - The present study demonstrates that an operant conditioning paradigm, originally
designed for assessing olfactory performance in a small New World primate, the
squirrel monkey, can successfully be adapted for use with a large Old World
primate, the pigtail macaque. Using a task designed to simulate olfactory-guided
foraging behavior, based on multiple discrimination of simultaneously presented
odor stimuli, we could show that Macaca nemestrina is able to learn to
discriminate between objects on the basis of odor cues. Moreover, they could
readily transfer to new S+ and S- stimuli and could remember the significance of
previously learned odor stimuli even after a 3-week break. Furthermore, we could
show that this method is suitable for obtaining reliable measures of olfactory
sensitivity. The few modifications of the original method employed here did not
affect essential features such as the mode of stimulus presentation (odorized
paper strips attached to manipulation objects) and the choice criterion (opening
or rejecting the odorized manipulation objects), thus for the first time enabling
valid interspecific comparisons of olfactory capabilities between a catarrhine
and a platyrrhine primate species. Our results indicate that M. nemestrina and
Saimiri sciureus are similar with regard to several measures of olfactory
performance, such as speed of initial task acquisition and ability to master
transfer tasks as well as their sensitivity to a food-related odorant.
PMID- 9761228
TI - Analysis of steroid hormone levels in female mice at high population density.
AB - Populations of predominantly female house mice (Mus musculus) were created by
placing virgin female mice in cages (0.045 m2 to 0.48 m2) with a single stud
male, and removing all ensuing male offspring at weaning. At maximum population
size, the females in these all-female/one-male populations exhibited male-like
aggressive behavior. Termination of the populations and subsequent measurement of
steroid hormone levels indicated that the aggressive females had high circulating
level of testosterone and corticosterone, and elevated baseline levels of
progesterone. The high levels of corticosterone could be lowered by
dexamethasone, but not the high levels of testosterone.
PMID- 9761229
TI - Flavor preferences conditioned by intragastric sugar infusions in rats: maltose
is more reinforcing than sucrose.
AB - Prior research indicates that glucose conditions much stronger flavor preferences
in rats than does fructose. This could occur because intestinal absorption of
fructose is much slower than that of glucose and because fructose malabsorption
may have aversive consequences. Fructose absorption is facilitated when glucose
is also present in the gut. The present study therefore compared the flavor
conditioning effects of maltose (a glucose + glucose disaccharide) to those of
sucrose (a glucose + fructose disaccharide). In Experiment 1, rats had different
flavors paired with intragastric infusions of 32% maltose (CS+M), 32% sucrose
(CS+S), and water (CS-) 23 h/day. In subsequent two-bottle tests, both CS+
solutions were strongly preferred to the CS-, but the CS+M was also preferred
(78%) to the CS+S. Experiment 2A revealed that the rats also learned to prefer a
CS+M to a CS+S when 16% sugar infusions were used. In Experiment 2B, the same
rats preferred a flavor paired with 16% maltose to a flavor paired with 8%
maltose. They did not reliably prefer a flavor paired with 16% sucrose to a
flavor paired with 8% maltose. These results demonstrate that the postingestive
actions of maltose are more reinforcing than those of sucrose. This indicates
that fructose is less reinforcing than glucose even when malabsorption is not a
factor. In contrast to their preference for the CS+M over the CS+S, the rats
preferred sucrose to maltose when drinking the sugars by mouth. Therefore, sugar
preferences mediated by oral taste receptors differ from those conditioned by
postoral nutrient detectors.
PMID- 9761230
TI - Vasopressin administration modulates anxiety-related behavior in rats.
AB - Experiments were performed to measure the influence of centrally and peripherally
applied arginine vasopressin (AVP) on anxiety-related behavior as indicated by
the elevated plus maze test. Central administration was performed into the septum
using a microdialysis technique. In initial experiments, the microdialysis probes
were characterized for substance application in vivo by means of 125I AVP,
measuring the substance-specific percent passover and the spatial distribution
around the microdialysis membrane within the brain. Both microdialysis
administration of 200 pg of AVP into the septum and and intraperitoneal
application of 500 ng of AVP induced an increase in the percentage of time spent
on the open arms of the elevated plus maze. The blockade of vasopressinergic
neurotransmission or neuromodulation into the septal area by 40 ng of the AVP
receptor antagonist d(CH2)5Thyr(Et)VAVP failed to induce a significant effect in
this respect. The observation that neither centrally nor peripherally applied AVP
influenced the locomotor activity on the elevated plus maze supports the
hypothesis that AVP is involved in the modulation of anxiety-related behavior in
rats.
PMID- 9761231
TI - The olfactory loss that accompanies an HIV infection.
AB - A number of studies have shown that HIV infection is associated with decreased
olfactory ability. Additionally, it has been hypothesized that a reduced odorant
identification may precede the advent of AIDS Dementia Complex (ADC). However, it
is not known whether changes in olfactory ability are a manifestation of
neurocognitive decline which may precede the appearance of AIDS Dementia Complex,
damage to the peripheral olfactory system from opportunistic infection, or
whether olfactory structures have a particular sensitivity to HIV. These issues
were addressed in a cross-sectional study examining variability in the
neuropsychological, neurological, otolaryngological, auditory, and olfactory
status in HIV-positive subjects. A stepwise regression provided evidence that the
ability to identify odorants was influenced by age, nasal structure and
pathology, neurocognitive ability, and level of AIDS Dementia Complex. On the
other hand, only nasal pathologies accounted for the variability in olfactory
thresholds. These data suggest that identification and thresholds tests may
reflect different olfactory pathologies. Additionally, these data suggest at
least part of the decline in olfactory ability accompanying an HIV infection may
be secondary to nasal pathologies. Because of their rapidly changing
neurocognitive status, HIV-positive patients represent an excellent group in
which to study the determinants of olfactory ability.
PMID- 9761232
TI - Synergy between amylin and cholecystokinin for inhibition of food intake in mice.
AB - Several gastrointestinal peptides which are secreted in response to nutrients
have been reported to suppress food intake. Amylin is a peptide hormone co
secreted with insulin from pancreatic beta-cells in response to nutrient stimuli.
Cholesystokinin (CCK) is secreted from duodenal and jejunal mucosal cells in
response to fat and protein. Amylin and CCK-8 have been reported to reduce food
intake in rodents when given centrally as well as peripherally. Amylin injected
intraperitoneally (i.p.) reduced food intake over the subsequent 30 min in
overnight fasted mice by a maximum of 57 +/- 6% with an ED50 of 0.93 nmol/kg
(3.63 microg/kg) +/- 0.34 log units. On a molar basis, this potency was similar
to that of CCK-8 (ED50 0.85 nmol/kg (0.97 microg/kg) +/- 0.28 log units; p =
0.93) which inhibited food intake by a maximum of 71 +/- 7%. When amylin and CCK
8 were injected i.p. as an amylin:CCK-8 mixture, immediately before presentation
of food in overnight fasted mice, food intake in the subsequent 30 min was
reduced by a maximum of 91%, an amount that was greater than that producable by
i.p. injection of amylin or CCK-8 alone. Isobolar analysis revealed a marked
synergy between amylin and CCK-8 in reducing food intake, such that statistically
ineffective doses of amylin and CCK, when combined, evoked near-maximal
inhibition of food intake. Because the typical physiological event is for amylin
and CCK both to be secreted in response to mixed meals, the synergy between them
could indicate a shared role in physiological appetite control.
PMID- 9761233
TI - Dietary protein restriction and selective preference for a protein-containing
diet in the golden hamster (Mesocricetus auratus).
AB - Two experiments were performed to examine protein appetite in golden hamsters
(Mesocricetus auratus). In Experiment 1, hamsters were maintained for 10 days on
either a protein-free or a nutritionally complete maintenance diet, and they were
also given access to protein-rich and carbohydrate-rich test diets for 6 h/day.
Hamsters maintained on the protein-free diet strongly preferred the protein test
diet, but hamsters on the complete diet showed no such preference even when their
caloric intake was matched to that of hamsters on the protein-free diet. In
Experiment 2, hamsters that had developed a preference for the protein test diet
while maintained on the protein-free diet were given Purina Chow for 25 days to
permit them to recover from their protein deficiency. When later maintained on
the complete diet, these hamsters did not demonstrate a preference for the
protein test diet when maintained on the complete diet, but did so when returned
to the protein-free maintenance diet. These findings indicate that dietary
protein restriction causes hamsters to develop a strong preference for a protein
rich diet and that this preference may be manifested only in response to a
physiological need for protein.
PMID- 9761234
TI - The relation between skin conductance level and plus-maze behavior in male mice.
AB - The present study examined the correlation between anxiety scores and skin
conductance level in 29 male Swiss Albino mice. Skin conductance (SC) was
recorded with the SC unit and IBM-AT computer. Anxiety scores of mice were
obtained from the elevated plus-maze test. The main result of the present study
indicates that SC levels (SCLs) are negatively correlated with plus-maze behavior
scores (both entries and time spent on the open arms). Our results are consistent
with the findings which suggests that the higher the anxiety level the higher the
SCL. This study further demonstrates the utility of SCL as a measurement for
identifying anxiety in mouse. The interrelation between SCLs and plus-maze scores
and possible explanations of the results are discussed.
PMID- 9761235
TI - Sleep patterns of the volcano mouse (Neotomodon alstoni alstoni).
AB - Sleep-waking patterns of the volcano mouse were studied under laboratory
conditions. This rodent exhibits four states of vigilance: active wakefulness
(Aw), quiet wakefulness (Qw), slow-wave sleep (SWS), and paradoxical (PS), or
rapid-eye movement (REM) sleep. These states present, in general, the classic
mammalian electrophysiological patterns. Although sleep periods were distributed
at any time of the nychthemeral cycle, they showed the tendency to concentrate
between 0800 and 2000 hours. The volcano mouse may be considered as a "good"
sleeper, because it shows a relatively high percentage of sleep from the total
recording time (TRT). Slow-wave sleep occupied 64.54 +/- 8.84% (mean +/- SD) of
the total recording time, while 7.56 +/- 1.31% corresponded to rapid-eye movement
sleep. The average duration of the rapid-eye movement sleep phase was 126.48 +/-
17.79 s, exhibiting an average recurrence of 49 +/- 9.28 phases throughout the
nychthemeral cycle. Mean duration of the sleep cycle was 9.23 +/- 2.36 min.
Quantitative data of the volcano mouse sleep may be considered adequate for its
body size and characteristic of an animal which sleeps in secure places under
free-living conditions.
PMID- 9761236
TI - AACC 50th anniversary retrospective. The evolution of immunoassay as seen through
the journal Clinical Chemistry. American Association for Clinical Chemistry.
PMID- 9761237
TI - Comprehensive analytical strategy for mutation screening in 21-hydroxylase
deficiency.
AB - Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease with a
wide range of clinical manifestations. It is most often caused by deficiency of
steroid 21-hydroxylase, reflecting any of a wide range of mutations in the 21
hydroxylase (CYP21) gene. A major challenge in molecular diagnostics of CAH is
the high homology between the CYP21 gene and the CYP21P pseudogene and the
phenomenon of apparent gene conversion, which inactivates the functional gene. In
this study we devised an improved stepwise diagnostic procedure involving
nonradioactive Southern blotting and direct DNA sequencing. This strategy led to
a successful elucidation of the molecular cause of the disease in 181 out of 182
unrelated alleles in a total of 91 clinically and biochemically characterized
patients. We were able to identify all classical known disease-causing mutations
of the 21-hydroxylase gene and a novel nonsense mutation (bp 670, A-->C, Y97X).
Our method also allows the reliable, secure diagnosis of the heterozygous
configuration and may therefore be used for pre-, peri-, and postnatal diagnosis
of CAH, even when informative data of the index patient are lacking. Furthermore,
it can be used to confirm the diagnosis of CAH in newborns detected in 17
hydroxyprogesterone screening programs.
PMID- 9761238
TI - Plasma concentration, kinetic constants, and gene polymorphism of angiotensin I
converting enzyme in centenarians.
AB - We have determined serum activity and kinetic constants of angiotensin I
converting enzyme (ACE), parallel to an insertion/deletion (I/D) polymorphism in
its gene, in French centenarians and controls 20-70 years of age because this
enzyme could have an impact on cardiovascular risk, and thus on longevity. Both
the ACE D allele and ACE D/D genotype were more frequent in centenarians in
comparison with controls, without sex-related differences nor significant
correlation with a cardiovascular pathology. In centenarians, I/D polymorphism
was correlated with circulating ACE activity (D/D genotype, 89.0 +/- 36.8 U/L;
I/D genotype, 63.5 +/- 26.0 U/L; and I/I genotype, 55.1 +/- 39.4 U/L). The
Michaelis constants for two substrates were identical whatever the genotype and
were not different between centenarians and controls, i.e., 0.30 +/- 0.03 mmol/L
for furylacryloyl-phenylalanyl-glycyl-glycine and 1.35 +/- 0.05 mmol/L for
hippuryl-histidyl-leucine; for the latter, the optimal pH and activating
concentration of chloride did not depend on I/D polymorphism. The maximal
velocities with both substrates reflected the distribution of serum ACE activity
as a function of the genotypes, in centenarians and in controls. In conclusion,
plasma ACE activity is subject to a similar genotypic influence in centenarians
as in adults 20-70 years of age; however, ACE itself appears to be functionally
similar for each genotype. Furthermore, the D allele as well as the higher serum
ACE activities associated with the D/D genotype cannot discriminate individuals
at high risk for cardiovascular diseases, major causes of mortality before the
age of 100 years.
PMID- 9761239
TI - New sensitive method for the detection of the A3243G mutation of human
mitochondrial deoxyribonucleic acid in diabetes mellitus patients by ligation
mediated polymerase chain reaction.
AB - An adenine-to-guanine mutation at nucleotide position (np) 3243 in the
mitochondrial tRNALeu(UUR) gene is closely associated with various clinical
phenotypes of diabetes mellitus. Because the mutation creates a new restriction
site for the restriction enzyme ApaI, the mutation is usually detected and
quantified by ApaI cleavage of the PCR products including np 3243. The
sensitivity of the conventional method is, however, 5-10% heteroplasmy. The
percentage of heteroplasmy of the mutation is usually highest in the affected
tissues and is much lower in peripheral blood cells, which are used most
frequently for the analysis. The sensitivity of the conventional method, however,
is not sufficient to detect the mutation from peripheral blood cells. Utilizing
ligation-mediated polymerase chain reaction, we have developed a feasible and
sensitive method to detect 0.01% heteroplasmy of the 3243 mutation in peripheral
leukocytes.
PMID- 9761240
TI - Evaluation of the lysosome-associated membrane protein LAMP-2 as a marker for
lysosomal storage disorders.
AB - For many lysosomal storage disorders, presymptomatic detection, before the onset
of irreversible pathology, will greatly improve the efficacy of current and
proposed therapies. In the absence of a family history, presymptomatic detection
can be achieved only by a comprehensive newborn screening program. Recently we
reported that the lysosome-associated membrane protein LAMP-1 was increased in
the plasma from approximately 70% of individuals with lysosomal storage
disorders. Here we report on the evaluation of a second lysosome-associated
membrane protein, LAMP-2, as a marker for this group of disorders. The median
concentration of LAMP-2 in the plasma of healthy individuals was 1.21 mg/L,
fourfold higher than the median LAMP-1 concentration (0.31 mg/L). LAMP-2 was
increased in >66% of patients with lysosomal storage disorders, and the increases
coincided with increased LAMP-1 concentrations. The reference intervals for LAMP
1 and LAMP-2 in blood spots taken from newborns were 0.20-0.54 mg/L (n = 1600)
and 0.95-3.06 mg/L (n = 1600), respectively. A high correlation was observed
between the concentrations of LAMP-1 and LAMP-2 in both control and affected
individuals. The higher concentrations of LAMP-2, relative to LAMP-1, in plasma
make LAMP-2 an attractive marker; however, the final selection will be dependent
on the availability of new diagnostic markers and their ability to detect
disorders currently not identified by LAMP-2.
PMID- 9761241
TI - K-ras mutations in stools and tissue samples from patients with malignant and
nonmalignant pancreatic diseases.
AB - Mutant-enriched PCR and reverse dot blot hybridization in microplates were
applied for examining K-ras status in stools and tissue samples from patients
with pancreatic tumors and chronic pancreatitis. In tissue samples, K-ras
mutations were found in 32 of 35 cases of ductal adenocarcinoma, in 5 of 7
periampullary cancers, in 1 cystadenocarcinoma, and in 3 of 5 patients with
chronic pancreatitis. In stools, mutated K-ras was seen in 10 of 25 cases of
ductal adenocarcinoma, in 1 case of cystadenocarcinoma, and in 2 of 6 cases of
chronic pancreatitis. These data indicate that the K-ras status of stool samples
may help identify pancreatic carcinoma and persons at risk for cancer
development; however, it does not allow discrimination of malignant from
nonmalignant diseases.
PMID- 9761242
TI - Chemical mismatch cleavage combined with capillary electrophoresis: detection of
mutations exon 8 of the cystathionine beta-synthase gene.
AB - Mutation detection by chemical mismatch cleavage (CMC) is based on the chemical
modification and cleavage at the site of mismatched C or T in heteroduplexes,
using hydroxylamine or osmium tetroxide (OsO4) as chemical probes. In the present
study, we evaluated CMC in combination with capillary electrophoresis (CE) by
determining the common T833C and G919A mutations in exon 8 of the cystathionine
beta-synthase gene in heterozygous and homozygous samples. A 186-bp fragment
encompassing exon 8 was amplified by PCR with both primers labeled with 5'
fluorescein. Labeled single strands of 40 and 61 nucleotides (nt) were formed
from the coding strand of the T833C sample and non-coding strand from the G919A
sample, respectively. These single-stranded DNA (ssDNA) products were analyzed
under denaturing conditions by CE with short-chain linear polyacrylamide as the
sieving matrix and were detected by laser-induced fluorescence (LIF), using a
sensitive, one-channel sheath-flow detector. The CE-LIF format afforded
relatively high resolution of ssDNA (down to 1 nt), precise size assessment of
CMC products, sensitive detection with small sample requirements, and fast
analysis. Thus, CMC combined with CE-LIF is suitable for screening of known
mutations, giving expected CMC products, but will also detect unknown mutations,
the locations of which are indicated by the fragment sizes.
PMID- 9761243
TI - The precursor form of the human kallikrein 2, a kallikrein homologous to prostate
specific antigen, is present in human sera and is increased in prostate cancer
and benign prostatic hyperplasia.
AB - Prostate-specific antigen (PSA, hK3) is a diagnostic marker for prostatic cancer
but lacks the specificity to sufficiently distinguish between prostatic cancer
and benign prostatic hyperplasia (BPH). Human glandular kallikrein 2 (hK2) has
been proposed as a potential diagnostic marker for prostate cancer that could
complement the current PSA test. Recently we demonstrated that proPSA is present
in prostate cancer sera. This study examines the expression of prohK2 in prostate
cells and its presence in human sera. Western blot analysis was used to assess
prohK2 expression in the human carcinoma cell line, LNCaP. A highly specific and
sensitive dual monoclonal immunoassay for prohK2 was developed and used to assess
the presence of prohK2 in human sera. prohK2 was detected in the spent media of
LNCaP cells. Furthermore, prohK2 was present at immunodetectable concentrations
in human sera, and its concentration was increased in prostatic cancer and BPH.
These results indicate for the first time that prohK2 is secreted by human
prostate cells and is a major component of uncomplexed (free) hK2 in human sera.
In addition, prohK2 in human sera is associated with prostate disease and thus
may be a useful marker for prostatic cancer and BPH.
PMID- 9761244
TI - Intra- and interindividual variability of carbohydrate-deficient transferrin,
gamma-glutamyltransferase, and mean corpuscular volume in teetotalers.
AB - Blood samples for determination of the biochemical alcohol markers carbohydrate
deficient transferrin (CDT) in serum, gamma-glutamyltransferase (GGT) in serum,
and erythrocyte mean corpuscular volume (MCV) were collected once every 1-2 weeks
over approximately 5 months from 10 female and 4 male teetotalers. Mean values
for serum CDT (using the CDTect assay) ranged from 9.9 to 29.4 units/L (median,
14.2 units/L), and the highest results were obtained in the women. The mean
values for serum GGT ranged from 0.15 to 0.49 microkat/L (median, 0.30
microkat/L, or 18 U/L) except for one woman with a very high mean of 3.07
microkat/L. For MCV, the mean values ranged from 79.5 to 91.5 fL. Two women
showed several CDT results above the upper reference limit (mean values, 27.6 and
29.4 units/L, respectively); however, their GGT and MCV values fell within the
reference intervals. One of these women exhibited an increased total transferrin
concentration (mean value, 5.38 g/L), which was possibly related to the use of
oral contraceptives and/or a low serum iron concentration. When the CDTect value
was expressed relative to total transferrin, a ratio within the reference
interval was observed for this woman but not for the other woman with increased
CDTect values. The present study demonstrates a considerable variation between
individuals in CDT, GGT, and MCV without drinking any alcohol. The results also
show that these baseline values are fairly constant over time within the same
individual.
PMID- 9761245
TI - Urinary free deoxypyridinoline by chemiluminescence immunoassay: analytical and
clinical evaluation.
AB - We evaluated an automated chemiluminescence immunoassay (CLIA) developed for the
measurement of urinary free deoxypyridinoline (DPD). The new DPD method by CLIA
is based on the competition of DPD with particle-bound pyridinoline for a limited
amount of monoclonal mouse anti-DPD antibody. Total imprecision (CV) was 3.2-9.0%
at 30-270 nmol/L. Regression analysis of urinary DPD concentration (second
morning-void) measured by CLIA (y) and enzyme immunoassay (EIA) for adult
volunteers (n = 449) with and without bone disease revealed a best fit equation
of: y = 1.08 +/- 0.03x - 1.15 +/- 0.98 nmol/L (r = 0.964, S(y/x) = 14 nmol/L).
CLIA and EIA methods were correlated with HPLC measurement of urinary free DPD (r
= 0.846 and 0.871, respectively). For healthy adults, the creatinine-normalized
excretion of DPD (mean +/- SD) measured by CLIA for 61 men (4.1 +/- 1.2 micromol
DPD/mol creatinine) and 76 premenopausal women (5.3 +/- 1.8 micromol DPD/mol
creatinine) did not differ significantly (P >0.05) from DPD excretion measured by
EIA, and both immunoassays showed a significant gender difference (P <0.001) in
reference intervals. In a clinical trial, DPD excretion (micromol DPD/mol
creatinine) measured by CLIA differed substantially from the reference population
for 54 untreated pagetic (12.7 +/- 8.0 SD), 255 untreated osteoporotic (7.5 +/-
4.1), 21 osteomalacic (12.4 +/- 8.5), 17 primary hyperparathyroid (9.4 +/- 4.4),
and 14 secondary hyperparathyroid (9.2 +/- 5.1) patients. Clinical sensitivities
of the CLIA and EIA methods range from 38% to 80% in bone disorders and limit the
use of the DPD measurement in disease detection. DPD excretion after pamidronate
treatment in a subgroup of the pagetic patients fell dramatically as assessed by
CLIA or EIA. We conclude that the automated CLIA method for DPD is a convenient
and reliable method that may aid in the evaluation and management of bone disease
and is applicable to high volume testing in the routine clinical laboratory.
PMID- 9761246
TI - Rapid, quantitative nonisotopic assay for telomerase activity in human tumors.
AB - Telomerase is a ribonucleoprotein enzyme that adds TTAGGG repeats onto human
telomeres, preventing their shortening. The activation of this enzyme is an
important step in cell immortalization and carcinogenesis and seems to represent
a new and promising marker in cancer diagnosis and management. Telomerase
activity is usually detected in cellular protein extract by the telomeric repeat
amplification protocol (TRAP) assay, which can provide only a qualitative
(presence/absence) evaluation. Here we present a modification of this method that
can provide quantitative information without requiring time-consuming post-PCR
procedures such as gel electrophoresis with radioactive materials and
autoradiography. The detection and measurement of telomerase activity is
performed by evaluating the amount of double-stranded DNA generated in the
telomerase reaction and PCR amplification, with the use of the sensitive DNA
fluorescent dye PicoGreen. In a subset of tumors, the presence of telomerase
activity was confirmed by the conventional TRAP assay. By this method we
evaluated telomerase activity in unselected groups of breast (n = 15), ovarian (n
= 12), endometrial (n = 12), gastric (n = 20), and renal (n = 12) carcinomas, in
meningiomas (n = 8), and in pheochromocitomas (n = 10). The results indicate
substantial differences of telomerase activity among cancer groups; however, a
large variability among patients of the same group is observed. Kidney, ovarian,
and breast carcinomas showed the highest mean values (31.8 +/- 28.9, 29.2 +/-
26.7, and 35.3 +/- 15.9 ng DNA/microg protein, respectively, mean +/- SD),
whereas gastric and endometrial cancers had a lower activity (17.2 +/- 8.8 and
13.5 +/- 7.9 ng DNA/microg protein, respectively). Very low or no detectable
telomerase activity was found in meningiomas (with the exception of one malignant
atypical variant) and pheochromocitomas (9.7 +/- 12.9 and 2.8 +/- 2.1 ng
DNA/microg protein, respectively). In conclusion, our method seems to be an
accurate and reasonable procedure for measuring telomerase activity in human
cancers.
PMID- 9761247
TI - Analytical and clinical performance characteristics of Tandem-MP Ostase, a new
immunoassay for serum bone alkaline phosphatase.
AB - The performance characteristics of the Tandem-MP Ostase assay, a new microplate
immunoassay for bone-specific alkaline phosphatase (bone ALP; EC 3.1.3.1) in
human sera, are described. Bone ALP is bound to streptavidin-coated microwells by
a single biotinylated anti-bone ALP monoclonal antibody. Antigen is detected by
the addition of p-nitrophenyl phosphate. The assay is performed at room
temperature in <90 min. Imprecision was 2.3-6.1% with a detection limit of 0.6
microg/L. Method comparison of bone ALP measurements with the Tandem-MP Ostase
assay and the mass-based Tandem-R Ostase assay (n = 285) indicated regression
statistics of Tandem-MP Ostase = 1.03 Tandem-R Ostase + 0.22 microg/L, S(y/x) =
4.0 microg/L, r = 0.97. Serum bone ALP values in apparently healthy men and in
pre- and postmenopausal women were also similar between the two Ostase assay
formats. Liver ALP reactivity determined using the slope and heat inactivation
methods was similar in both Ostase assays. Liver ALP reactivity ranged from 3
microg/L (heat inactivation) to 6 microg/L (slope method) per 100 U/L of liver
ALP activity, whereas bone ALP reactivity was 37 microg/L per 100 U/L of bone ALP
activity, indicating a liver ALP relative reactivity of 8.1-16.2%. Similar
results were obtained with the Alkphase-B bone ALP immunoassay. The Tandem-MP
Ostase bone ALP assay demonstrated increased concentrations of serum bone ALP in
conditions where bone metabolism is increased and showed a rapid, temporal
decrease in serum bone ALP in Paget disease patients on bisphosphonate therapy.
In conclusion, the Tandem-MP Ostase assay for serum bone ALP is a rapid, simple,
robust nonisotopic alternative to the Tandem-R Ostase immunoradiometric assay
that provides an accurate and sensitive assessment of bone turnover.
PMID- 9761248
TI - Measurement of LDL particle size in whole plasma and serum by high performance
gel-filtration chromatography using a fluorescent lipid probe.
AB - We have recently described a technique for measuring LDL size by high performance
gel-filtration chromatography (HPGC) with UV detection (Scheffer et al., Clin
Chem 1997;43:1904-12). A drawback of this method is the necessity of LDL
isolation before chromatography. We now describe a modification of this method
based on selective detection of lipoproteins by postcolumn labeling with
parinaric acid, a fluorescent lipid probe. Measuring the size of isolated LDL by
HPGC in 56 subjects, we obtained diameters of 25.72 +/- 0.60 nm with UV detection
and of 25.74 +/- 0.58 nm with fluorescence detection. The modified method is
suitable for LDL size measurement in whole plasma or serum. LDL sizes measured in
whole plasma correlated strongly with the respective values in isolated LDL (r =
0.976) but were on average 0.18 nm larger (P < 0.001). CVs for within- and
between-series imprecision were <0.25%. The present method requires only 5 microL
plasma or serum without sample preparation and is suitable for the unattended
analysis of large series of samples.
PMID- 9761249
TI - Enzyme immunoassay of urinary mevalonic acid and its clinical application.
AB - We have developed an enzyme immunoassay for mevalonic acid (MVA), using a
specific monoclonal antibody. The intra- and interassay coefficients of variation
calculated on two urine samples were 3.3% and 3.4%, respectively, in the
intraassay precision test and 3.5% and 6.9% in the interassay evaluation.
Pravastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase
inhibitor, was administered to nine healthy men, and in all cases, their MVA
excretion rates then decreased. The more MVA that was excreted in the urine
before the pravastatin administration, the greater a reduction of MVA excretion
was observed. The daily MVA excretions in healthy men (n = 120) and women (n =
105) were 2.32 micromol/day (SD, 0.82 micromol/day) and 1.85 micromol/day (SD,
0.47 micromol/day), respectively. In streptozotocin-induced diabetic rats (n =
14), the plasma cholesterol concentrations and MVA excretion rates were
increased, and a positive correlation was observed between the plasma cholesterol
and the urinary MVA concentrations.
PMID- 9761250
TI - Cyclosporin whole blood immunoassays (AxSYM, CEDIA, and Emit): a critical
overview of performance characteristics and comparison with HPLC.
AB - Assays with different specificity are used for cyclosporin monitoring in clinical
transplantation. A recent survey of 35 centers showed that 86% used immunoassays
for cyclosporin A (CsA). In consensus documents the following performance
criteria were recommended: (a) imprecision < or = 10% at 50 microg/L and < or =
5% at 300 microg/L; and (b) comparison with the reference method (HPLC) should
yield a slope of 0.9-1.1, an intercept of -15 to 15 microg/L, and S(y/x) < or =
15 microg/L. The newly developed CsA assays for the AxSYM (Abbott) and the CEDIA
(Boehringer Mannheim) as well as the Emit assay (Behring Diagnostica) were
evaluated. Results from samples of heart, kidney, and liver recipients (100
specimens each) were compared with a validated HPLC-ultraviolet detection method.
Between-series imprecision (CV) with commercial controls was 5.8% and 1.7% for
AxSYM (70 and 300 microg/L), 11% and 5.5% for CEDIA (90 and 200 microg/L), and
8.1% and 4.5% for Emit (63 and 172 microg/L). In the presence of 300 microg/L
parent CsA, cross-reactivities were (for AxSYM, CEDIA, and Emit, respectively)
7%, 4%, and none for AM1 (1 mg/L) and 12.6%, 25%, and 6% for AM9 (0.5 mg/L).
Comparison with HPLC showed in heart and kidney recipients an average
overestimation with the Emit and the CEDIA of approximately 22%, with
overestimation in the AxSYM of 32%. In liver recipients, the most challenging
patient group, the CEDIA and the AxSYM showed a mean overestimation of 43% and
47%, respectively, and the Emit differed by 31% compared with HPLC. None of the
immunoassays fully satisfied the performance criteria recommended in the
consensus documents. In terms of specificity, Emit ranks before CEDIA, which
ranks before AxSYM. Regarding imprecision, the ranking is AxSYM < Emit < CEDIA.
These limitations must be considered when using these assays for therapeutic drug
monitoring of CsA in clinical transplantation.
PMID- 9761251
TI - Development of a sensitive ELISA for human leptin, using monoclonal antibodies.
AB - A new, sensitive ELISA for human leptin in plasma and cerebrospinal fluid (CSF)
was developed, using monoclonal antibodies. The lower limit of detection of this
ELISA was 0.78 pg/assay. Both intra- and interassay imprecision values were <7%.
The dilution curves of plasma and CSF showed good linearity, and the recovery was
83.2-95.6%. There was good correlation between plasma leptin concentrations by
the ELISA and a commercially available RIA (r = 0.99). Our ELISA is advantageous
because it does not require radioisotopes, it produces results in hours rather
than days, and more importantly, it improves on the detection limit and plasma
interference of the RIA kit. The new ELISA enables measurement of low
concentrations of leptin, as are seen in CSF and in plasma of patients with
anorexia nervosa.
PMID- 9761252
TI - Hemoglobin Rambam (beta69[E13]Gly-->Asp), a pitfall in the assessment of diabetic
control: characterization by electrospray mass spectrometry and HPLC.
AB - Hemoglobin (Hb) Rambam, or beta69[E13]Gly-->Asp, has been identified in a German
woman also suffering from non-insulin-dependent diabetes mellitus and chronic
obstructive pulmonary disease. This is the first observation of this Hb variant
in a German family thus far. The detailed evaluation of its structure using
electrospray mass spectrometry revealed new minor glycohemoglobin components and
showed that the attachment of glucose to the beta NH2 terminus occurred at an
almost identical rate in both wild-type and mutant beta-chains. However, the
introduction of a carboxyl group at beta69 seems to increase the glycation of
epsilon-amino groups of lysine residues. The glycemic state in the propositus was
well reflected by the total glycohemoglobin concentrations but not by the Hb A1c
values, which did not reflect hemoglobin glycation in this patient. This case
demonstrates that Hb A1c cannot be used reliably in the management of diabetic
patients carrying Hb variants such as Hb Rambam. Functional studies of the whole
blood of the heterozygous carrier demonstrated extremely low oxygen affinity,
which may have been caused by increased 2,3-diphosphoglycerate related to chronic
obstructive pulmonary disease and hyperthyroidism. None of the clinical symptoms
could be directly associated to Hb Rambam.
PMID- 9761253
TI - The analog free testosterone assay: are the results in men clinically useful?
AB - Men with low testosterone concentrations are usually hypogonadal. However,
because variations in the testosterone transport protein, sex hormone-binding
globulin (SHBG), directly influence the total testosterone concentration,
confirmation of a low testosterone with a measurement of free testosterone or
"bioavailable" testosterone (BAT) is recommended. In the present study, we
examined the relationship of SHBG with free testosterone (Coat-A-Count assay,
Diagnostic Products) and with BAT in men (n = 29) and women (n = 28) who
participated in a study of the metabolic determinants of body composition. As
expected, total testosterone was strongly positively correlated with SHBG among
men (r = 0.68; P <0.01). Although the BAT was independent of SHBG in men (r =
0.02), SHBG was an important predictor of free testosterone (r = 0.62; P <0.01).
In contrast, in women serum concentrations of total testosterone (r = -0.26; P =
0.17), free testosterone (r = -0.30; P = 0.17), and BAT (r = -0.46; P = 0.013)
all tended to be lower with increasing SHBG. Free testosterone was nearly
perfectly positively correlated with total testosterone (r = 0.97) in men, among
whom free testosterone represented a relatively constant percentage of the total
testosterone (0.5-0.65%), and the percentage of free testosterone was unrelated
to SHBG. Thus the Coat-A-Count free testosterone concentration in men, like the
total testosterone concentration, is determined in part by plasma SHBG.
Accordingly, androgen deficiency may be misclassified with this assay in men with
low SHBG. Moreover, the previous findings of reduced free testosterone
concentrations with hypertension or hyperinsulinemia or as a risk factor for
developing type 2 diabetes, conditions in which SHBG is reduced, may have been
methodology-related.
PMID- 9761254
TI - CO-oximetry interference by perflubron emulsion: comparison of hemolyzing and
nonhemolyzing instruments.
AB - Perflubron emulsion is expected to be in clinical use soon as a non-hemoglobin
blood substitute. A preliminary report indicates that this new oxygen-carrying
fluorocarbon interferes with the measurements of CO-oximeters. Therefore, we have
quantified the interference that perflubron causes in the measurements of eight
widely used oximeters and CO-oximeters. The AVL Omni 6, CC270, IL482, IL682, and
OSM3 are conventional CO-oximeters that hemolyze blood samples before analyzing
them. In contrast, the AVOXimeters 1000 and 4000 and the IL Synthesis 35 make
their measurements without hemolyzing the samples. Because perflubron is expected
to be used most frequently on surgical patients in a hemodiluted state, we
conducted all tests on human erythrocytes suspended in plasma at a hemoglobin
concentration standardized to 70 g/L (7 g/dL) and with oxyhemoglobin saturation
set at 97%. When perflubron was added to the blood samples, the nonhemolyzing CO
oximeters were not seriously affected by perflubron concentrations in and above
the therapeutic range. In contrast, some of the hemolyzing CO-oximeters
experienced concentration-dependent interference in their measurements of all
analytes except total hemoglobin concentration. Thus, we conclude that the
nonhemolyzing CO-oximeters provide an effective means for determining whether a
hemolyzing CO-oximeter is experiencing clinically important interference in blood
from patients receiving perflubron.
PMID- 9761255
TI - Rapid pathogen detection using a microchip PCR array instrument.
AB - An array of PCR microchips for rapid, parallel testing of samples for pathogenic
microbes is described. The instrument, called the Advanced Nucleic Acid Analyzer
(ANAA), utilizes 10 silicon reaction chambers with thin-film resistive heaters
and solid-state optics. Features of the system include efficient heating and real
time monitoring, low power requirements for battery operation, and no moving
parts for reliability and ruggedness. We analyzed cultures of Erwinia herbicola
vegetative cells, Bacillus subtilis spores, and MS2 virions, which simulated
pathogenic microbes such as Yersinia pestis, Bacillus anthracis spores, and
Venezuelan equine encephalitis, respectively. Detection of microbes was achieved
in as little as 16 min with detection limits of 10(5)-10(7) organisms/L (10(2)
10(4) organisms/mL).
PMID- 9761256
TI - Reasons for a laboratory's inability to report results for requested analytical
tests.
PMID- 9761257
TI - Reference intervals for biochemistry parameters for evaluation of oxidative
stress in human sperm.
PMID- 9761258
TI - Evaluation and intermethod comparison of the Bio-Rad high-performance liquid
chromatographic method for plasma total homocysteine.
PMID- 9761259
TI - Use of real-time quantitative PCR to compare DNA isolation methods.
PMID- 9761260
TI - Addition of sodium fluoride to whole blood does not stabilize plasma homocysteine
but produces dilution effects on plasma constituents and hematocrit.
PMID- 9761261
TI - Verification of multichannel liquid dispenser performance in the 4-30 microL
range by using optical pathlength measurements in microplates.
PMID- 9761262
TI - Oligo(dT)-immobilized pipette tip: efficient new methodology for mRNA preparation
and direct gene amplification.
PMID- 9761263
TI - Genotyping in urine: an interesting tool for epidemiological studies.
PMID- 9761264
TI - False increase of cardiac troponin I with heterophilic antibodies.
PMID- 9761265
TI - Reference intervals for four biochemistry analytes in plasma for evaluating
oxidative stress and lipid peroxidation in human plasma.
PMID- 9761266
TI - Limit of quantification (functional sensitivity) of the new IMx Tacrolimus II
microparticle enzyme immunoassay.
PMID- 9761267
TI - Temporal changes of serum antioxidant concentrations in a patient with diabetic
ketoacidosis.
PMID- 9761268
TI - False-positive CDTect values in patients with low ferritin values.
PMID- 9761269
TI - Suitability of plastic collection tubes for cyclosporine measurements.
PMID- 9761270
TI - Response to a report on false-positive results in a methadone enzyme immunoassay.
PMID- 9761271
TI - Diagnostic criteria for diabetes mellitus.
PMID- 9761272
TI - Effect of antiresorptive therapy on day-to-day variation of urinary free
deoxypyridinoline excretion.
PMID- 9761273
TI - Association between chronic hepatitis C virus infection and increased neopterin
concentrations in blood donations.
PMID- 9761274
TI - Diurnal variability and in vitro stability of carbohydrate-deficient transferrin.
PMID- 9761275
TI - Desiccated coconut as a quality-control material in fecal fat measurements.
PMID- 9761276
TI - Extracellular matrix production regulation by TGF-beta in corneal endothelial
cells.
AB - PURPOSE: Production of extracellular matrix (ECM) by corneal endothelial cells is
related to physiologic functions and pathologic conditions and is regulated by
many cytokines, including transforming growth factor-beta (TGF-beta). In this
study, the molecular mechanism of ECM production regulation by TGF-beta was
investigated in cultured corneal endothelial cells. METHODS: The production of
ECM components (laminin and fibronectin) was detected in cultured corneal
endothelial cells by western blot analysis. To determine the signal transduction
pathways, mutant TGF-beta type I receptor (TbetaR-I) and/or Smad protein family
members (intracellular signal transducers in TGF-beta signaling) were
overexpressed by transfecting their cDNA into the cultured cells, and the effects
on ECM production were observed. RESULTS: The production of laminin and
fibronectin was stimulated by treatment with TGF-beta1 or TGF-beta2. After
transient transfection of cDNA of the constitutively active (CA) mutant of TbetaR
I, the production of laminin and fibronectin was stimulated even in the absence
of TGF-beta. The transfection of the dominant negative mutant of TbetaR-I
counteracted the effects of TGF-beta. These results confirm that TGF-beta
directly stimulates ECM production from corneal endothelial cells through TbetaR
I. The ECM production stimulation by TGF-beta or CA TbetaR-I was accelerated by
the overexpression of Smad2, Smad3, and/or Smad4 and inhibited by that of Smad7.
These results show that TGF-beta signals connected to ECM production are
regulated by Smad family members, located downstream of TbetaR-I. CONCLUSIONS:
The results of this study show that TGF-beta stimulates ECM production from
corneal endothelial cells through TbetaR-I and Smad family transducers.
PMID- 9761277
TI - Proteoglycan turnover in the sclera of normal and experimentally myopic chick
eyes.
AB - PURPOSE: The turnover of chick scleral proteoglycans from control and form-vision
deprived (myopic) eyes was compared in vivo and in explant cultures to determine
whether proteoglycan degradation is altered during the development of myopia and
to characterize the mechanism of proteoglycan turnover in the sclera. METHODS:
Seven-day-old chicks were radiolabeled via an intraperitoneal injection of 35SO4,
and monocular form deprivation was induced 48 hours later. After 1, 2, and 3
weeks of form deprivation, birds were killed, and the amount of 35SO4
proteoglycans remaining in different scleral regions was measured in control and
deprived eyes. Posterior sclera were also radiolabeled in organ culture
containing 35SO4, and radiolabeled scleral proteoglycans were chased into
unlabeled medium for 0 to 11 days. 35SO4-labeled proteoglycans within the scleral
matrix and those released into the medium were characterized by Sepharose CL-2B
chromatography and western blot analysis. RESULTS: The biological half-life of
scleral proteoglycans was significantly shorter within the posterior pole of form
deprived eyes (t1/2 = 7.212 days) compared with the same region of control eyes
(t1/2 = 9.619 days; P < 0.001), whereas no differences in turnover rates were
seen in the anterior sclera or equatorial sclera. When posterior scleral punches
were placed in organ culture, 35SO4-labeled proteoglycan turnover rates were
similar for control and form-deprived eyes. Chromatographic and western blot
analyses indicated that approximately 80% of the total 35SO4 within the posterior
sclera is incorporated into the aggrecan. Western blot analyses of aggrecan core
protein released into the medium by control and form-deprived scleral punches
indicated that the core protein was degraded into a series of smaller fragments
of Mr = 102 to 220 kDa. A specific antiserum (anti-FVDIPEN) detected the presence
of a 50-kDa C-terminal aggrecan fragment released into the medium, which was
generated by the action of the matrix metalloproteinase gelatinase A and/or
stromelysin. CONCLUSIONS: The turnover rate of 35SO4-labeled scleral
proteoglycans is vision dependent and is accelerated in the posterior sclera of
chick eyes during the development of experimental myopia. The loss of
proteoglycans from the scleral matrix involves proteolytic cleavage at various
sites along the aggrecan core protein through the action, at least in part, of
gelatinase A and/or stromelysin.
PMID- 9761278
TI - Raman detection of macular carotenoid pigments in intact human retina.
AB - PURPOSE: To develop and test a novel noninvasive optical technique suitable for
the objective measurement of macular carotenoid levels in human retina. METHODS:
A resonance Raman scattering apparatus was constructed to measure carotenoid
levels in flat-mounted human retinas and eyecups and in experimental animal eyes.
Light from an argon laser was used to resonantly excite the electronic absorption
of the carotenoid pigments, and scattered light was collected and analyzed by a
Raman spectrometer. After carotenoid Raman measurements were completed on the
retinal samples, macular carotenoid levels were determined by high-performance
liquid chromatography (HPLC). RESULTS: Carotenoid resonance Raman scattering
proved to be a highly sensitive and specific method for the noninvasive
measurement of macular pigments in the human retina. Signal strength scaled
linearly with actual macular carotenoid content as measured by HPLC. Our
apparatus was also used to record resonance Raman signals from xanthophyll
carotenoids stored in the retinal pigment epithelium of intact frog eyes.
CONCLUSIONS: This new noninvasive optical method will facilitate studies of
ocular carotenoid distributions and their role in degenerative diseases of the
eye and may allow for the rapid screening of carotenoid levels in large
populations at risk for vision loss from age-related macular degeneration, the
leading cause of blindness in the elderly in the United States. A prototype
clinical instrument is under development.
PMID- 9761279
TI - Rabbit Streptococcus pneumoniae keratitis model and topical therapy.
AB - PURPOSE: To develop a model for experimental Streptococcus pneumoniae keratitis
and to evaluate the chemotherapeutic efficacy of 12 common topical antibiotics in
vivo. METHODS: Five-hundred (CFUs of log-phase S. pneumoniae were injected into
the central corneal stroma of 36 eyes of 18 rabbits. After 0, 4, 8, 16, 24, and
48 hours, the in vivo growth was assayed as the CFU per cornea. Epithelial
removal (to promote antibiotic entry and mimic human keratitis) was evaluated.
Disc or tube dilution verification of the sensitivity or resistance of three S.
pneumoniae strains was performed: a penicillin sensitive ("S"), an intermediate
sensitive ("I"), and a resistant ("R") strain. Keratitis was established with S.
pneumoniae "S" in 65 eyes, S. pneumoniae "I" in 107 eyes, and S. pneumoniae "R"
in 78 eyes. Sixteen hours later, control corneas were harvested and the
epithelium removed from treatment corneas. Every half hour saline, penicillin,
gentamicin, bacitracin, ciprofloxacin, ofloxacin, erythromycin, vancomycin,
ceftriaxone, cefotaxime, or chloramphenicol was applied for 5 hours. One hour
later CFUs/cornea were assayed. RESULTS: After 24 hours, S. pneumoniae "S" and
"I" had proliferated to 9.18+/-6.65 x 10(6) CFUs and 9.26+/-6.90 x 10(6) CFUs.
Epithelial removal at 16 hours was not significant. The in vitro antibiotic
sensitivity was as expected. However, in vivo, penicillin, gentamicin, or
cefazolin sterilized S. pneumoniae "S." S. pneumoniae "R" responded best to
fortified gentamicin with or without vancomycin; all others antibiotics were
significantly less effective (P < 0.001). CONCLUSIONS: A small intracorneal S.
pneumoniae inoculum in rabbit corneas grew and was maintained for 24 hours (with
epithelial removal) to provide a model for testing antibiotic sensitivity in
vivo. Topical penicillin is best for treating keratitis from penicillin-sensitive
S. pneumoniae, whereas topical gentamicin or a combination of gentamicin and
vancomycin was most effective against penicillin-resistant S. pneumoniae.
PMID- 9761280
TI - Myofibroblast transformation of cat corneal endothelium by transforming growth
factor-beta1, -beta2, and -beta3.
AB - PURPOSE: Under certain pathophysiologic conditions, the corneal endothelium can
produce an abnormal posterior collagenous layer (PCL) that reduces light
transmission. Previous studies suggest that formation of PCLs can result from
transformation of endothelial cells to a proliferative myofibroblast phenotype.
The purpose of this study was to determine the potential role of transforming
growth factor (TGF)-beta on corneal endothelial transformation. METHODS: Three
corneal buttons (6-mm diameter) were obtained from each cornea of 28 adult cats.
After a 2-mm diameter mechanical scrape injury was made, each button was cultured
for 24, 48, or 72 hours in serum-free medium (SFM) or SFM supplemented with 10%
fetal calf serum, TGF-gamma1, TGF-beta2, TGF-beta3, basic fibroblast growth
factor (bFGF), or TGF-beta1 and bFGF. Buttons were single and double labeled
using phalloidin and antibodies to ZO-1, Ki67, fibronectin, alpha-smooth muscle
(SM) actin, and vinculin. Counts of Ki67-positive cells were used as a measure of
endothelial proliferation. RESULTS: Organ culture in TGF-beta1, beta2, or beta3
induced myofibroblast transformation of corneal endothelial cells, with formation
of stress fibers containing alpha-SM actin, loss of normal pericellular ZO-1
organization, development of extracellular fibronectin fibrils, and formation of
focal contacts as indicated by punctate vinculin staining. However, TGF-beta3 did
not stimulate endothelial proliferation above that in serum-free control samples.
Serum and bFGF each stimulated proliferation significantly, without inducing
myofibroblast transformation. A combination of TGF-beta1 and bFGF resulted in
both myofibroblast transformation and increased proliferation. CONCLUSIONS: These
results suggest that TGF-beta plays a key role in the loss of normal endothelial
differentiation, abnormal extracellular matrix synthesis, and myofibroblast
transformation, which can induce development of PCLs. However, other factors such
as bFGF seem to be required to stimulate concomitant proliferation of corneal
endothelium.
PMID- 9761281
TI - Investigation of multifocal visual evoked potential in anisometropic and
esotropic amblyopes.
AB - PURPOSE: To investigate the variation of visual evoked potential (VEP) function
at different eccentricities of the visual field in esotropic amblyopes and
anisometropic amblyopes. METHODS: Data from 5 esotropic amblyopic eyes, 6
anisometropic amblyopic eyes, and 45 control eyes were analyzed. A VERIS system
was used to generate a stimulus matrix containing 61 hexagons on a computer
monitor. Each hexagon of the display contained a number of small black and white
hexagonal patches that reversed in polarity during stimulation according to a
pseudorandom binary m-sequence. The VERIS system extracted the local responses by
cross-correlating the input and output signals. The latencies and amplitudes of
the responses from the central 8.6 degrees of arc in the visual field were
analyzed. RESULTS: In esotropic amblyopia, the multifocal VEP latency is
prolonged, and the amplitude is reduced in the central region of the visual
field. The mean amplitude is significantly smaller, and the mean latency is
significantly longer in the temporal visual field than in the nasal visual field.
In anisometropic amblyopia, latencies are markedly prolonged, and the amplitudes
of multifocal VEP are attenuated in the central region of the visual field, and
these effects are lessened in the periphery. CONCLUSIONS: The results are in
agreement with psychophysical studies reporting a greater foveal deficit in
amblyopia and a greater visual loss in the temporal field than in the nasal field
in esotropic amblyopia.
PMID- 9761282
TI - Two pore types in the inner-wall endothelium of Schlemm's canal.
AB - PURPOSE: It has been reported that fixation conditions significantly influence
the apparent pore density in the inner-wall endothelium of Schlemm's canal. In
the present study, the manner in which fixation conditions affect the two
subtypes of inner-wall pores, intracellular pores and intercellular (or border)
pores, was investigated. METHODS: Outflow facility was measured in enucleated
human eyes. Eyes were fixed under constant flow" or constant pressure conditions,
microdissected to expose the inner wall of Schlemm's canal, and prepared for
scanning electron microscopy. The density and diameter of the two subtypes of
pores in the inner wall were measured. RESULTS: Intracellular pore density
decreased with increasing postmortem time (P < 0.001) and increased with
increasing volume of fixative passed through the outflow pathway (P < 0.001),
whereas border pore density showed no dependence on these parameters (P > 0.25
and P > 0.15, respectively). Border pore density increased with increasing
fixation pressure (P < 0.005), even though intracellular pore density showed no
such dependence (P > 0.4). No correlation was found between outflow facility and
the predictions of Poiseuille's law, Sampson's law, or the funneling theory for
the hydraulic conductivity of the intracellular pores (P > 0.35) or the border
pores (P > 0.1). CONCLUSIONS: The intracellular and border pores form two
morphologically and functionally distinct populations in the inner wall of
Schlemm's canal. The dependence of intracellular pore density on postmortem time
and on volume of fixative passed through the outflow pathway suggests that these
pores are artifacts of tissue fixation or processing conditions. That border
pores do not depend on such conditions and that their presence is correlative
with perfusion pressure suggests that this population may be nonartifactual. New
histologic techniques for examining the inner wall of Schlemm's canal are
necessary to determine the in vivo state of inner-wall pores and how they
influence outflow facility.
PMID- 9761283
TI - Immunotolerance against a foreign antigen transgenically expressed in the lens.
AB - PURPOSE: To extend our knowledge concerning immunotolerance against autologous
lens crystallins, transgenic (Tg) mice that express a foreign antigen in their
lens were generated, and the immune response against the antigen in these mice
was analyzed. METHODS: Conventional techniques were used to generate lines of Tg
mice that express soluble (S-) or membrane-bound (M-) hen egg lysozyme (HEL)
under the control of the alphaA-crystallin promoter. The presence of HEL in
various organs was determined by the particle concentration fluorescence
immunoassay (PCFIA), and reverse transcription-polymerase chain reaction
technique was used to detect mRNA transcripts of the molecule. To examine the
development of immunity (or tolerance), Tg mice and their wild-type controls were
immunized with HEL (25 microg) in Freund's complete adjuvant and 14 days later
were tested for immune response against the antigen. Cellular immunity was
measured by the lymphocyte proliferation assay and cytokine production, and
humoral immunity was determined by enzyme-linked immunosorbent assay. RESULTS:
Eyes of the high copy number M-HEL Tg mice were dystrophic, with disrupted lens,
whereas no morphologic changes were detected in the eyes of the other Tg mouse
lines. All Tg mice exhibited tolerance to HEL by their cellular and humoral
immune compartments. The state of immunotolerance to HEL was retained in the Tg
mice for as long as 10 months after removal of the main depot of this protein, by
enucleation. Measurable amounts of HEL were found in the eyes of all Tg mice, but
the protein could not be detected in the serum or in other organs by the
sensitive PCFIA (with a threshold of 1 ng/ml). Yet, HEL mRNA was found in the
thymus of the Tg mice, suggesting that minute amounts of the protein are
expressed in this organ. CONCLUSIONS: The unresponsiveness to HEL in the Tg mice
seems to be due to a "central" mechanism of tolerance, mediated by a minuscule
amount of HEL in the thymus. Conversely, the much larger amounts of HEL in the
peripheral depot, the eyes, play a minor role if any in the tolerogenic process.
It is further proposed that a similar mechanism of central tolerance is
responsible for the immunotolerance against autologous lens crystallins.
PMID- 9761284
TI - Fluorescence and immunochemical studies of advanced glycation-related lens
pigments.
AB - PURPOSE: To establish whether advanced glycation is the major mechanism for
yellowing of lens proteins. METHODS: Synchronous fluorescence (SF) and
immunochemical assays were used to study glycation in vitro and in vivo. In the
in vitro study, advanced glycation end products (AGEs) were prepared and used as
antigens to induce antibodies to AGEs. The in vitro AGEs and classified nuclear
cataracts were analyzed by SF and immunochemical assays. RESULTS: In vitro AGEs
generated from various glycating agents and carrier proteins displayed strong SF
above 350 nm; the spectra were well resolved with major bands at 380 nm and 420
nm. Samples from human lenses manifested a band at 395 nm in addition to the two
bands shown by in vitro AGEs. SF intensity is greater for the water-insoluble
(WI) than water-soluble (WS) fraction, but both increased with increasing nuclear
color. The immunoreactivity data also showed that the WI fraction contained more
AGEs than the WS fraction and that the amount of AGEs increased with increasing
nuclear color. CONCLUSIONS: Fluorescence and immunoassays indicated that
pigmented AGEs contributed to yellowing of the crystalline lens nucleus.
PMID- 9761285
TI - Angiotensin II and insulin induce growth of ciliary artery smooth muscle: effects
of AT1/AT2 antagonists.
AB - PURPOSE: Abnormal growth of smooth muscle cells (SMCs) in small arteries of the
eye is associated with hypertension and diabetes, and the complications that they
induce. Migration and proliferation of SMCs into the intima are primary
mechanisms involved in neointima formation. In aortic SMCs, angiotensin II (AII)
induced proliferation is inhibited by angiotensin type 1 (AT1) receptor
antagonist. However, in small artery SMCs, in particular in the circulation of
the eye, the effects of AII on migration and proliferation are unknown. METHODS:
The effects of AII (10(-6) to 10(-10) M) on migration and proliferation of growth
arrested SMCs of porcine ciliary arteries were studied in the presence and
absence of insulin (5 x 10(-10) M) by assaying DNA synthesis (3H-thymidine
incorporation), cell number, and movement of SMCs across the membrane of a
modified Boyden chamber. RESULTS: In the absence of insulin, only high
concentrations (10(-6) to 10(-8) M) of AII induced DNA synthesis and increased
cell number (P < 0.05); however, in the presence of insulin (5 x 10(-10) M), AII
induced DNA synthesis and cell number at low concentrations (10(-10) M) and in a
concentration-dependent manner (P < 0.05). In contrast to proliferation, AII
induced SMC migration in a concentration-dependent manner in the absence of
insulin (P < 0.05). The AT1 antagonist CGP48933 (10(-8) to 10(-12) M), but not
the AT2 antagonist CGP42112 (10(-8) to 10(-12) M), inhibited AII (10(-8) M)
induced proliferation and migration in a concentration-dependent manner (P <
0.05). CONCLUSIONS: Our results suggest that AII is a potent mitogen for SMCs of
ophthalmic arteries, an effect that is enhanced in the presence of insulin, and
that it may be an important contributor to structural vascular changes in the
ophthalmic circulation in hypertension associated with non-insulin dependent
diabetes. The inhibition of AII-induced growth by an AT1 antagonist suggests that
these drugs may be important therapeutic tools to prevent structural vascular
changes in the ophthalmic vasculature under these conditions.
PMID- 9761286
TI - Regulation of corneal endothelial barrier function by adenosine, cyclic AMP, and
protein kinases.
AB - PURPOSE: To determine which processes or factors that regulate corneal hydration
are responsible for the hydration-modulating effects of adenosine. Influx of
fluid to the stroma and efflux to the aqueous humor are governed, respectively,
by the imbibition pressure of the stromal matrix and the transendothelial ionic
gradients determined by the permeability and active transport characteristics of
this monolayer. The focus of this study was to assess the effects of adenosine on
these endothelial parameters. METHODS: Isolated corneas freshly dissected from
rabbit eyes were used throughout. Active ion transport was assessed by
measurement of 86Rb+ uptake by the endothelial cells of intact corneas incubated
for 30 minutes in 25 mM HCO3(-)-Ringer with agents promoting corneal
deturgescence or corneal swelling. Intracellular and extracellular fluid in the
scraped endothelial cell mass was estimated from simultaneous counts of 3H
mannitol and 14C-urea, allowing calculation of tissue-to-medium (T-M) ratios of
86Rb+ in cell water. Permeability of the endothelium was determined by measuring
the efflux into the superfusate of 5-carboxyfluorescein (CF) applied to the
stroma of deepithelialized corneas superfused at the endothelial surface with the
same media described for 86Rb+ uptake. Thickness of these corneas and of others
fixed for scanning electron microscopy was monitored with a specular microscope.
RESULTS: In the control medium, 25 mM HCO3(-)-Ringer, 86Rb+ was accumulated to
yield a T-M ratio of 6.21. Neither adenosine nor other agents that increase
cyclic adenosine monophosphate (cAMP)--that is, forskolin and dibutyryl cAMP-
changed this value to a significant extent. Bumetanide had no effect, but ouabain
caused a decrease in T-M to 1.30, a 79% inhibition. Elimination of Na+ or HCO3-
also caused marked decreases in uptake. Permeability to CF in control medium was
3.40 x 10(-4) cm/min. A decrease of more than 20% (P < 0.05) was seen in the
presence of adenosine and cAMP promoters and also with the protein kinase
inhibitor H-8, whereas phorbol myristate acetate caused an increase to 4.50 x 10(
4) cm/min (P < 0.01). Ouabain caused no change, but blocked the effects of
adenosine. Reducing the Ca2+ concentration of the superfusing medium caused time
dependent increases in permeability to 4.57 at 15 to 45 minutes and 12.5 at 80 to
110 minutes. At the earlier time, this increase in permeability could be
prevented by the addition of adenosine or H-8. Elimination of Na+ or HCO3- ions
from the medium caused a small decrease in permeability and, like ouabain,
blocked the effect of adenosine. Changes in thickness of corneas were consistent,
in most cases, with the observed alterations in 86Rb+ uptake or permeability to
CF. Scanning electron microscopy showed contraction and rounding of endothelial
cells in low Ca2+ medium, with stretching of intercellular borders, features that
were largely eliminated when adenosine was also present. CONCLUSIONS: Adenosine,
through increasing cAMP, decreases permeability of the corneal endothelium. This
effect, rather than a change in the active transport (fluid pump) mechanism, is
responsible for the promotion of deturgescence and maintenance of lower steady
state thickness of corneas exposed to adenosine. The mechanism may involve the
phosphorylation state of cytoskeletal proteins and seems to be dependent on an
undisturbed environment of monovalent ions.
PMID- 9761287
TI - Mammalian orthologs of C. elegans unc-119 highly expressed in photoreceptors.
AB - PURPOSE: To characterize orthologous human and murine cDNAs isolated through
separate screens designed to identify genes expressed preferentially in retina.
METHODS: By screening bovine, murine, and human retinal cDNA libraries, human UNC
119 clones of two varieties and a murine cDNA clone corresponding to the most
abundant human transcript were isolated. Northern blot and reverse transcription
polymerase chain reaction analyses were used to determine tissue distribution of
UNC-119 expression; in situ hybridization localized it in retina to
photoreceptors. Fluorescence in situ hybridization was used to map the human
structural gene, and its intron- exon boundaries were elucidated by polymerase
chain reaction amplification and sequencing genomic DNA. RESULTS: UNC-119 was
expressed at high levels in photoreceptors and at low levels elsewhere. The most
abundant transcript encoded a protein of 240 amino acids with homology to
Caenorhabditis elegans UNC-119. Rat and human cDNAs of UNC-119 have been
previously reported as human retinal gene 4 and rat retinal gene 4 (HRG4 and
RRG4). An alternative splice form in humans arose from retention of the 3'-most
intron, seemed to be retina-specific, and encoded a protein of 220 amino acids.
The human structural gene mapped to 17q 1.2 and comprised at least five exons and
four introns. A patient with neurofibromatosis type 1, which also maps to
17q11.2, and cone-rod dystrophy was examined for a deletion of UNC-119 but no
abnormalities were found. CONCLUSIONS: Given its strong degree of evolutionary
conservation and abundant and nearly exclusive expression in photoreceptors, it
is likely that UNC-119 plays an important role in vision and is a strong
candidate gene for retinal diseases that map to 17q11.2.
PMID- 9761288
TI - Expression of cathepsin S antisense transcripts by adenovirus in retinal pigment
epithelial cells.
AB - PURPOSE: To show the production of sense or antisense transcripts by recombinant
adenoviruses, to investigate whether the transcripts produced were suitable for
downregulating the expression of the targeted gene, cathepsin S (CatS), and to
examine the effect of antisense transcript production on the biologic function of
retinal pigment epithelial (RPE) cells, including the regulation of endogenous
aspartic protease expression. METHODS: Ad.MLP.CatSAS, Ad.RSV.CatSAS, and
Ad.MLP.CatSS recombinant viruses were produced by homologous recombination. The
recombinant viruses were tested by restriction enzyme digestion to confirm the
orientation of the inserts. The expression of antisense transcripts was tested by
northern blot analysis. Western blot analysis was used to study the regulation of
the endogenous CatS protein in ARPE19 cells. The biologic effect of CatS
downregulation in ARPE19 cells was tested by proliferation and phagocytosis
assays, de novo cathepsin D (CatD) synthesis, and measurement of aspartic
protease activity. RESULTS: After characterization of the recombinant adenovirus
constructs, the production of antisense and sense CatS transcripts was shown in
ARPE19 cells. The transcripts appeared at approximately 1.9 kb 48 hours after
transduction, and the expression of the antisense transcripts was similar in
constructs carrying either the MLP or the RSV promoter. Western blot analysis
showed that ARPE19 cells transduced with Ad.MLP.CatSAS and Ad.RSV.CatSAS had no
detectable CatS. In contrast, there was a strong signal appearing at 24 kDa in
ARPE19 cells transduced with Ad.MLP.CatSS. ARPE19 cells were transduced to a high
level. The transduction of ARPE19 cells with the recombinant adenoviruses did not
affect the morphologic appearance of the cells, their proliferation, or their
phagocytosing ability. However, ARPE19 cells transduced by Ad.MLP.CatSAS
recombinant adenovirus showed a significant downregulation of de novo CatD
synthesis and a twofold decrease in aspartic protease activity. CONCLUSIONS:
Recombinant adenoviruses were shown to be suitable for producing antisense CatS
transcripts to modulate endogenous CatS expression in RPE cells. It is proposed
that CatS may play an important role, directly or indirectly, in the lysosomal
digestion of outer segments through the regulation of other lysosomal enzyme
activity, such as the expression of CatD.
PMID- 9761289
TI - Estrogen receptor expression in bovine and rat retinas.
AB - PURPOSE: To investigate the expression and distribution of estrogen receptor
protein and mRNA in bovine and rat retinas. METHODS: Western blot analysis with
an antiestrogen receptor monoclonal antibody (mAb) was used to detect estrogen
receptor protein in the bovine retina. Immunohistochemistry with an antiestrogen
receptor mAb and in situ hybridization with an oligodeoxynucleotide sequence
coding for estrogen receptor were applied to study the cellular distribution of
estrogen receptor protein and its mRNA in male bovine retina and rat retina of
both sexes. RESULTS: Estrogen receptor protein was detected in bovine retina by
Western blot analysis. Immunohistochemical staining with the antiestrogen
receptor mAb was widespread throughout the neural retina. Specific staining
showed extensive distribution localizing in the nerve fiber layer, the ganglion
cell layer, the inner nuclear layer, and the outer plexiform layer. Retinal
pigment epithelium and choroid were also stained with the antiestrogen receptor
mAb. By in situ hybridization, the expression of estrogen receptor mRNA was
predominantly observed in ganglion cell layer, the inner nuclear layer, and outer
portion of the outer nuclear layer. No significant difference was found between
male and female rats in the immunostaining of retinas with the antiestrogen
receptor mAb. CONCLUSIONS: This study provides the first evidence for the
presence of estrogen receptor in bovine and rat retinas. Expression of estrogen
receptor throughout the retina suggests that estrogen may have important
functions in the retina.
PMID- 9761290
TI - Vitreous treatment of retinal pigment epithelial cells results in decreased
expression of FGF-2.
AB - PURPOSE: Changes in gene expression were investigated after treatment of cultured
human retinal pigment epithelial (RPE) cells with vitreous. This may have
implications for proliferative diseases such as proliferative vitreoretinopathy.
METHODS: Cells were cultured in the presence or absence of human vitreous, and
gene expression was examined using the differential display polymerase chain
reaction technique. Differentially expressed RNAs were cloned, screened for
differential expression, and sequenced. The expression of one of these RNAs (that
for fibroblast growth factor [FGF]-2/basic FGF) was examined by in situ
hybridization and ribonuclease protection assays. The level of FGF-2 protein was
examined by immunoblot analysis. The effects of adding FGF-2 to cells cultured in
the presence of vitreous were examined. RESULTS: Treatment of low passage human
RPE cells with 25% vitreous resulted in the epithelial-to-fibroblast-like
morphologic changes reported by others and in the decreased expression of FGF-2
mRNA and FGF-2 protein. Addition of FGF-2 to cultures at the same time as
addition of vitreous prevented some of the effects of vitreous on these cells.
CONCLUSIONS: Vitreous treatment of RPE cells in culture results in decreased
expression of FGF-2 mRNA and protein. Because supplementation of FGF-2 prevents
some of the vitreous-mediated effects, this may indicate that modulation of FGF-2
levels by the vitreous may play an important role in the phenotypic changes seen
in RPE cells exposed to vitreous.
PMID- 9761291
TI - Intact sheets of fetal retina transplanted to restore damaged rat retinas.
AB - PURPOSE: The aim of this study was to establish a model for morphologic retinal
reconstruction after destruction of photoreceptors. METHODS: Rat embryos were
prelabeled by injection of bromodeoxyuridine (BrdU) into timed pregnant rats on 2
to 6 consecutive days. Pieces of fetal retinas (embryonic day [E] 17 to E22) were
embedded in growth factor-reduced matrigel for protection and stored in medium on
ice. With the use of a custom-mnade implantation tool, trimmed embedded pieces
were placed into the subretinal space of albino rats whose photoreceptors had
been damaged by continuous exposure to blue light for 3 to 4 days. RESULTS: Donor
cells were unequivocally identified by the BrdU label. Approximately 25% of
transplants in the subretinal space developed parallel layers, with photoreceptor
outer segments facing the host pigment epithelium. Transplants developed rosettes
if host pigment epithelium had been damaged, if trauma to the donor tissue
occurred during preparation or transplantation, and if the donor tissue was
misplaced into the choroid or into the epiretinal space on top of the host
retina. If the surgery was performed more than 4 weeks after the light damage,
continued degeneration of the host retina caused secondary pigment epithelium
damage, and transplants did not develop parallel layers of photoreceptor outer
segments. CONCLUSIONS: After transplantation to the subretinal space of a
degenerated retina, gel-protected fetal retina can develop parallel layers and
photoreceptor outer segments in contact with host pigment epithelium. Transplants
can develop good fusion with the inner retina of a photoreceptor-deficient
recipient.
PMID- 9761292
TI - The role of the p53 protein in the selective vulnerability of the inner retina to
transient ischemia.
AB - PURPOSE: To determine whether the p53 protein plays a role in the selective
vulnerability of the inner retina to transient ischemia. METHODS: Transient
retinal ischemia was induced using a high intraocular pressure (HIOP) model in
the Sprague-Dawley rat for 60 minutes. Histopathologic outcome was determined 7
days after ischemia. In addition, analysis for evidence for apoptosis (TdT-dUTP
terminal nick-end label [TUNEL] staining) and p53 protein expression
(immunohistochemistry) was performed at several points during the reperfusion
period. In a separate set of experiments, wild-type mice and two groups of
transgenic mice, one homozygous and the other heterozygous for the p53 null gene,
were also subjected to HIOP for 60 minutes, and histopathology was performed 7
days later. RESULTS: At 7 days subsequent to 60 minutes of ischemia in the rat,
there was marked thinning of the inner retinal layers. There were scattered TUNEL
positive cells within the inner retina, peaking at 24 to 48 hours and persisting
for at least 7 days. p53 immunochemistry demonstrated elevated protein levels
within the inner retina; this finding peaked at 24 to 48 hours but was no longer
present at 4 days after ischemia. TUNEL staining of the inner retina of the mouse
was most prominent 24 hours subsequent to ischemia but persisted at 48 hours.
Seven days subsequent to 60 minutes of ischemia in the wild-type and transgenic
mice, histopathologic evaluation demonstrated preservation of the retinal
histoarchitecture in the heterozygous group compared with the wild-type or
homozygous animals. CONCLUSIONS: These data further support the hypothesis that
the delayed cell death that occurs after transient retinal ischemia is, in part,
apoptotic. In addition, they suggest a role for the p53 protein in the selective
vulnerability of the inner retina to transient ischemia. p53 protein may be a
target for future therapeutic agents in the treatment of disorders of the retina
where ischemia plays a pathogenetic role.
PMID- 9761293
TI - Eye elongation during accommodation in humans: differences between emmetropes and
myopes.
AB - PURPOSE: The pathophysiology and pathogenesis of myopia are still a matter of
controversy. Exaggerated longitudinal eye growth is assumed to play an important
role in the development of myopia. A significant correlation between refraction
and amount of near-work has been reported. However, current knowledge of changes
of axial eye length with accommodation is limited because clinical ultrasound
biometry does not provide the precision and resolution required to thoroughly
investigate these phenomena. METHODS: Partial coherence interferometry (PCI), a
noninvasive biometric technique, uses laser light with short coherence length in
combination with interferometry to achieve precision in the micrometer to
submicrometer range and resolution of 10 microm. In the present study this
technique was used to investigate axial eye length changes in 11 emmetropic and
12 myopic eyes during monocular fixation at the far and near point. In 7
subjects, the contralateral eye has also been measured to investigate interocular
differences in eye elongation. RESULTS: All investigated eyes elongated during
accommodation. This elongation was more pronounced in emmetropes than in myopes
(P < 0.001). Mean accommodation-induced eye elongations of 12.7 microm (range,
8.6-19.2 microm) and 5.2 microm (range, 2.1-9.5 microm), corresponding to a
dioptric change of approximately -0.036 D and -0.015 D, were obtained for
emmetropes and myopes. No significant difference in accommodative amplitudes
between groups (5.1 +/- 1.2 D [range, 3.8-7.1 D] versus 4.1 +/- 2.0 D [range, 1.0
7.1 D]; P = 0.14) was detected. No significant interocular difference in
accommodation-induced eye elongation was revealed (P = 0.86). Also, a mean
backward movement of the posterior lens pole of 38 microm (range, 9-107 microm)
was observed in both study groups. CONCLUSIONS: The detected eye elongation can
be explained by the accommodation-induced contraction of the ciliary muscle,
which results in forward and inward pulling of the choroid, thus decreasing the
circumference of the sclera, and leads to an elongation of the axial eye length.
Finally, it was demonstrated that PCI, in contrast to clinical ultrasound, is
capable of characterizing eye length changes during accommodation in humans.
PMID- 9761294
TI - Extreme responsiveness of the pupil of the dark-adapted mouse to steady retinal
illumination.
AB - PURPOSE: To measure the dependence of the size of the pupils of mice on steady
retinal illumination. METHODS: Anesthetized C57BL/6 mice aged 7 to 8 weeks were
placed in a ganzfeld chamber in darkness, and in monochromatic (510 nm) and white
light whose intensity was varied more than 6 log units. The pupils of the mice
were photographed with an infrared video camera and recorded on videotape and the
pupil areas determined by digital image analysis of the video recordings.
RESULTS: Fully dark-adapted murine pupils had an area of 2.29 +/- 0.35 mm2. The
minimum pupil size at saturating intensity was 0.10 +/- 0.05 mm2. The steady
state pupil area declined to half its dark-adapted maximum when ganzfeld
luminance was 10(-5) scotopic candela (scot. cd) per meter squared. Pupil area
declined to 20% of the dark-adapted magnitude at approximately 10(-3) scot.
cd/m2. CONCLUSIONS: The mouse pupil can regulate retinal illumination by a factor
exceeding 20. The neural circuitry that determines steady state murine pupil size
is extremely sensitive to retinal illumination and under these experimental
conditions is controlled almost exclusively by rod signals. This follows, because
the ganzfeld illuminance (10(-5) scot. cd/m2) that causes the pupil to constrict
to half its dark-adapted value corresponds to only approximately 0.01
photoisomerization per rod per second, whereas 80% reduction in pupil area occurs
at approximately 1 photoisomerization per rod per sec. Based on this extreme
responsiveness to steady illumination, the hypothesis is proposed that the murine
pupil functions to protect a retinal circuit that can become saturated at
extremely low photon capture rates. General principles of dark-adapted retinal
circuitry support the identification of the first three neurons in the circuit as
the rod, the rod bipolar, and the AII-amacrine. The rod and rod bipolar neurons
do not approach saturation at the intensities at which the pupil constricts,
however, and it seems unlikely that the AII-amacrine does. Thus the retinal
neurons protected from saturation by the mouse pupil constrictions are probably
ganglion cells with large receptive fields that have sustained responses.
PMID- 9761295
TI - A new model of proliferative vitreoretinopathy.
AB - PURPOSE: To design a new model of proliferative vitreoretinopathy (PVR) that
would not rely on the addition of exogenous cells. The release of endogenous
cells from surrounding attachments seems to be an early event in the pathogenesis
of PVR. Because the proteolytic enzyme dispase dissociates tissues, the
hypothesis was that an intraocular injection of dispase could trigger events that
would cause PVR. The requirement for a surgical retinal break at the time of
dispase injection was also examined. METHODS: One eye of Dutch Belted rabbits was
injected with 0.003 U to 1.0 U dispase in the subretinal space or vitreous
cavity. Control rabbits received a saline injection. An intentional retinal tear
was created in animals in some groups. Observations were made for at least 10
weeks after surgery. RESULTS: Proliferative vitreoretinopathy developed in
response to subretinal or intravitreal dispase, with or without creation of a
controlled retinal break. Increased severity of PVR correlated with increasing
doses of dispase. Evidence of PVR included preretinal membranes, distortion of
myelin wings and retinal vessels, fixed retinal folds, and traction retinal
detachment. Proliferative vitreoretinopathy did not develop in saline-treated
control animals. CONCLUSIONS: Dispase initiated the development of PVR without
the addition of exogenous cells, growth factors, or cytokines typically found in
PVR membranes. A cascade of events was probably triggered by dispase, causing
native cells and factors to produce PVR. The dispase model of PVR was technically
easy to perform, permitted a clear view of the retina, and had a high success
rate in development of PVR.
PMID- 9761296
TI - Polyunsaturated fatty acids are lower in blood lipids of Usher's type I but not
Usher's type II.
AB - PURPOSE: Previous studies have shown that persons with retinitis pigmentosa and
Usher's syndrome have lower blood levels of long-chain polyunsaturated fatty
acids (PUFAs). In this study, the fatty acid composition of phospholipids from
plasma and red blood cells (RBCs) was compared in persons with Usher's syndrome
type I; Usher's syndrome type II; or no retinal disease (control subjects).
METHODS: Blood was drawn from fasting volunteers and separated into plasma and
RBCs by centrifugation. Lipids were extracted and phospholipids were obtained by
thin-layer chromatography. Fatty acid methyl esters were prepared and analyzed by
gas-liquid chromatography. RESULTS: There were no differences in plasma or RBC
phospholipid fatty acid composition between control subjects (n = 54) and persons
with Usher's syndrome type II (n = 20). However, all 20- and 22-carbon PUFA
levels from RBCs of persons with Usher's syndrome type I were lower than those
from control subjects and persons with Usher's Syndrome type II. Likewise, plasma
levels of 20:3n-6, 20: 5n-3, and 22:6n-3 were lower in Usher's syndrome type I
compared with the control group. In contrast, plasma levels of 18:1n-9 and RBC
levels of 16:0 and 18:1n-9 were higher in the group with Usher's syndrome type I.
CONCLUSIONS: Plasma and RBCs from Usher's syndrome type I, but not type II, have
lower levels of long-chain PUFAs than plasma and RBCs from control subjects.
PMID- 9761297
TI - Refractive error and age-related maculopathy: the Blue Mountains Eye Study.
AB - PURPOSE: To assess associations between refractive error (hyperopia, myopia, and
spherical equivalent [SEq]) and age-related maculopathy (ARM) in an older
population. METHODS: A population-based survey examined 3654 people aged 49 years
or older, 82% of whom were permanent residents in an area west of Sydney,
Australia. Participants had a detailed eye examination, including standardized
refraction and stereo macular photographs. ARM was diagnosed from blinded
photographic grading. Autorefractor measurements and subjective refraction were
used to assess SEq refractive error for each eye in diopters. Mean SEq of the two
eyes was used to define emmetropia, myopia, and hyperopia in each person.
RESULTS: After known ARM risk factors (age, sex, ARM family history, current
smoking) had been adjusted for, no association was found between mean SEq (two
eyes) and late ARM (odds ratio [OR], 1.0; 95% confidence interval [CI], 0.9-1.1).
However, a statistically significant increased risk of early ARM was found for
each diopter of increase in mean SEq (OR, 1.1; CI, 1.0-1.2). In logistic
regression models, moderate to high hyperopia was significantly associated with
increased early ARM risk (OR, 2.0; CI, 1.2-3.4). When a generalized estimating
equation model (GEE), which assessed the relationship at eye level while
accounting for the correlation between the two eyes, was used, this association
was marginally insignificant (OR, 1.3; CI, 0.9-1.9). No significant associations
were found between myopia and any ARM stage with either model. CONCLUSIONS: These
population-based data suggest a weak association between hyperopia and early ARM.
PMID- 9761298
TI - Effect of glutamate analogues and inhibitory neurotransmitters on the
electroretinograms elicited by random sequence stimuli in rabbits.
AB - OBJECTIVE: To study the origin of the different components of the
electroretinogram (ERG) elicited by a random binary m-sequence stimulus. METHODS:
Electroretinograms were recorded from pigmented rabbits before and after the
injection of glutamate analogues (2-amino-4-phosphono-butyric acid [APB; DL form]
and cis-2,3-piperidine-dicarboxylic acid [PDA]) and inhibitory neurotransmitters
(glycine and gamma-aminobutyric acid [GABA]) to abolish the contribution of
different cell types to the ERG. Two types of stimuli were used: conventional
full-field stimulation with short- and long-duration flashes and a random binary
m-sequence of flashes designed to mimic the pseudorandom binary m-sequence
stimulation used in the multifocal ERG technique. RESULTS: The effects of APB and
PDA on the first-order kernel of the random ERGs were similar to those on the
photopic short-flash ERG. Glycine and GABA minimized the oscillatory potentials
(OPs) of the photopic ERGs, and also reduced the amplitude of the positive wave
of the first-order kernel slightly but caused a large reduction in the amplitude
of the second-order kernel. CONCLUSIONS: The data suggest that the ON and OFF
bipolar cells contribute significantly to the photopic short-flash ERG, as
previously shown, and to the first-order kernel of the responses elicited by the
pseudorandom binary sequence stimuli. The second-order kernel and the OPs receive
a strong contribution from the cells of the inner retinal layers.
PMID- 9761299
TI - The vertical field border in hemianopia and its significance for fixation and
reading.
AB - PURPOSE: The existence of macular sparing, a central seeing area of several
degrees within the hemianopic field defect, has been controversial for a long
time, because inaccurate fixation during perimetry can produce ambiguous results.
The visual field border in hemianopia was studied to examine whether a vertical
strip of hemifield overlap described in monkeys exists in humans and whether
additional macular sparing could be found. METHODS: Vertical triplets of dots
were scanned on the retinas of eight patients (13 eyes) with hemianopia at
different eccentricity from the vertical meridian during strict simultaneous
fixation control using a scanning laser ophthalmoscope (SLO). Additionally, eye
movements were measured by SLO and by an infrared reflection system while
subjects read texts. RESULTS: Macular sparing of 2 degrees to 5 degrees and
absence of sparing were observed. The presence and amount of sparing influenced
fixation behavior, reading performance, and reliability of conventional
perimetry. The smaller the macular sparing, the less stable the fixation. In the
absence of sparing, either central unstable fixation with frequent saccades
toward the hemianopic side or eccentric fixation occurred, resulting in a shift
of the field defect toward the hemianopic side. A vertical strip of sometimes
partial perception was found in 12 eyes at 0.5 degrees from the midline.
CONCLUSIONS: Macular sparing and a slight vertical strip of hemifield overlap
exists in humans. Adaptive strategies like eccentric fixation and predictive
saccades improve reading performance and can augment rehabilitation.
PMID- 9761300
TI - Influences of chorion type on saccadic eye movements in twins.
AB - PURPOSE: The influence of genetic and prenatal environmental factors on
characteristics of saccadic performance were evaluated in young monozygotic (MZ)
twins (8-19 years old) of known chorion type. METHODS: Saccadic eye movements
were recorded using an infrared system. Saccadic latency, accuracy, and
parameters of amplitude-peak velocity exponential equation (main sequence) were
quantified. RESULTS: Intraclass correlations of saccadic parameters differed
significantly from zero for monochorionic and dichorionic MZ twins. The within
pair mean squares were significantly less, and intraclass correlations were
significantly higher in monochorionic than in dichorionic twins for latency and
were similar for other saccadic parameters (accuracy, slope of main sequence, and
peak velocity for 15 degrees saccades). CONCLUSIONS: These findings confirmed
previous reports that saccadic parameters of MZ twins are significantly
correlated and indicated that similarity of these parameters seen in MZ twins may
be driven both by genetic and by prenatal environmental factors.
PMID- 9761301
TI - In vivo demonstration of increased leukocyte entrapment in retinal
microcirculation of diabetic rats.
AB - PURPOSE: Leukocytes have been reported to be less deformable and more activated
in diabetes. It has also been suggested that they cause microvascular occlusions
that may cause diabetic microangiopathy. This study was designed to evaluate in
vivo leukocyte dynamics in the retinal microcirculation of diabetic rats.
METHODS: Streptozotocin (STZ)-induced diabetic rats 4 weeks after diabetes
induction and spontaneously diabetic Otsuka Long-Evans Tokushima Fatty (OLETF)
rats with 6 weeks' duration of diabetes were used in this study. Leukocyte
dynamics were observed with acridine orange digital fluorography, using a nuclear
fluorescent dye of acridine orange and high-resolution images from a scanning
laser ophthalmoscope. RESULTS: There was no significant difference in capillary
leukocyte velocity between the STZ-induced diabetic rats (1.27 +/- 0.12 mm/sec,
mean +/- SD) and nondiabetic control subjects (1.38 +/- 0.07 mm/sec) or between
OLETF rats (1.31 +/- 0.17 mm/sec) and the nondiabetic controls, Long-Evans
Tokushima Otsuka (LETO) rats (1.29 +/- 0.11 mm/sec). In contrast, the density of
leukocytes trapped in the retinal microcirculation was significantly elevated in
the STZ-induced diabetic (2.5-fold; P < 0.01) and the OLETF rats (2-fold; P <
0.01) compared with leukocyte density in the control subjects. CONCLUSIONS:
Pharmacologically induced and spontaneously diabetic rats showed increased
leukocyte entrapment in the living retina in the early stages of diabetes. In
light of the damaging potential of leukocytes, accumulation of leukocytes in
diabetic retinas from the preretinopathy stage could cause microvascular
occlusions and dysfunction, in turn causing diabetic retinopathy.
PMID- 9761302
TI - Matrix metalloproteinases and metalloproteinase inhibitors in choroidal
neovascular membranes.
AB - PURPOSE: Matrix metalloproteinases (MMP) are a family of extracellular matrix
degrading enzymes associated with the development of neovascularization. To
investigate the possible role of these enzymes in choroidal neovascularization,
the mRNA expression of MMPs and tissue inhibitors of metalloproteinases (TIMPs)
were analyzed in subfoveal fibrovascular membranes from patients with age-related
macular degeneration (AMD). METHODS: Surgically removed subfoveal fibrovascular
membranes from five eyes were analyzed for the expression of MMP and TIMP mRNA.
In situ hybridization anti-sense and sense riboprobes were generated using DNA
complementary to human collagenase (MMP-1), 72 kDa gelatinase (MMP-2),
stromelysin (MMP-3), 92-kDa gelatinase (MMP-9), TIMP-1, TIMP-2, and TIMP-3.
Vascular endothelial cells were detected using immunostaining for von Willebrand
factor. RESULTS: MMP-2 and MMP-9 mRNA were detected in all specimens. Most of the
membranes also expressed TIMP-1 and TIMP-3 mRNA, and two of the membranes
expressed TIMP-2 mRNA. MMP-2, TIMP-1, and TIMP-2 mRNA had a similar overall
distribution that was relatively uniform within the vascularized membrane stroma.
MMP-2 expression appeared to be localized mainly to the vascular endothelial
cells, whereas TIMP-1 and TIMP-3 were detected in other cell types such as
fibroblastlike cells. MMP-9 expression was distinctly expressed by cells at the
margins of the membranes and often in proximity to a thickened Bruch's membrane
like layer under the retinal pigment epithelial cells. TIMP-3 mRNA was strongly
expressed within the retinal pigment epithelial cell layer and also in the stroma
of one membrane. None of the membranes showed detectable MMP-1 or MMP-3
expression. CONCLUSIONS: The results support a role for MMPs in the development
of choroidal neovascularization in AMD. The localization of MMP-2 and MMP-9 to
the areas of new vessel formation and to the enveloping Bruch's-like membrane,
respectively, suggests that MMP-2 and MMP-9 may be cooperatively involved in the
progressive growth of choroidal neovascular membranes in AMD.
PMID- 9761303
TI - Choroidal blood flow in AMD.
PMID- 9761304
TI - Research on the human brain in an epilepsy surgery setting.
AB - Recent advances in our understanding of the fundamental mechanisms of epilepsy
have derived, to a large extent, from improvements in designing parallel human
and animal studies. This is the result not only of better animal models of human
epileptic phenomena, but of an increasing ability to carry out detailed invasive
studies on patients in the course of surgical treatment for medically refractory
epilepsy. In addition to interictal and ictal video-EEG recordings with chronic
depth and subdural electrodes, it is also possible to sample single-unit activity
with chronically implanted microelectrodes, and measure constituents of
extracellular fluid with chronically implanted microdialysis probes, using
protocols that in the past were possible only in the experimental animal
laboratory. Subsequent surgical resection provides tissue that can be used for
electrophysiological, morphological, biochemical, and molecular biological
investigations. Patients in epilepsy surgery facilities represent a precious
resource for research that should be utilized to the fullest extent possible by
basic scientists interested in mechanisms of epilepsy. It is particularly
important that invasive research be pursued now, because improved diagnostic
technology is greatly reducing the need for chronic intracranial electrode
recordings, and surgical approaches that do not yield tissue could be used more
commonly in the future. Therefore, the capacity to carry out invasive research in
the context of epilepsy surgery may diminish greatly over time. To take full
advantage of these opportunities, carefully designed iterative experimental
protocols are necessary to characterize abnormalities in the human epileptic
brain, to create appropriate experimental animal models to study these phenomena
in greater detail, and to return to the human brain to validate the clinical
relevance of observations made on animals. It is also important, however, to
recognize certain unavoidable limitations of human research, including ethical
considerations, variability inherent in the clinical setting, imprecision in
defining target areas, lack of control data, and small subject numbers, which
continue to make animal investigations essential to the achievement of our goals
of defining fundamental mechanisms of human epileptic phenomena.
PMID- 9761305
TI - Tuberous sclerosis-related gene expression in normal and dysplastic brain.
AB - Cortical dysplasia (CD) broadly defines a complex cerebral malformative lesion
associated clinically with intractable, pharmacoresistant epilepsy (including
infantile spasms), especially in infants and children. In CD, the spectrum of
structural brain abnormalities includes (at a minimum) neuronal dyslamination and
(in severe cases) neuronal cytomegaly with cytoskeletal alterations and the
presence of gemistocyte-like 'balloon cells'. In some CD variants, the
neuropathological features are essentially indistinguishable from those of a
tuber of tuberous sclerosis (TSC). Two genes associated with the autosomal
dominant, multi-system disorder TSC have recently been cloned: TSC2 (on
chromosome 16p13.3) encodes the protein tuberin and TSC1 (on 9q34) encodes
hamartin. Tuberin has been immunolocalized to neurons and possibly astrocytes in
normal brain and CD/TSC tubers, and is widely expressed in normal viscera; loss
of heterozygosity and tissue culture studies suggest it functions as a growth
suppressor. The TSC1 gene has been cloned within the last year and hamartin as
yet has no well-defined cellular function, though its protein product may also
function as a growth suppressor. This article focuses on the cellular
pathogenesis of CD and TSC brain lesions and how the two may be biologically
related. Studies of how TSC1 and TSC2 function in normal and dysplastic cerebral
neocortex may provide a paradigm for understanding the neurobiology of other
genes that determine epilepsy-associated cerebral malformations (e.g.
lissencephaly, double cortex).
PMID- 9761306
TI - Glutamate receptor mechanisms in human epileptic dysplastic cortex.
AB - Developmental disorders of neuronal migrations in the human brain are referred to
as 'cortical dysplasia', and current knowledge of cortical dysplasia is limited
to varied pathologic descriptions which lack specific investigations of glutamate
receptor mechanisms. In this study, immunocytochemistry was used to study the
expressions of glutamate receptor subunit proteins for NMDAR2A/B, NMDAR1 and AMPA
Glu-R2/3 in human brain resected for intractable epilepsy associated with
cortical dysplasia. Seventeen patients were studied with batch-matched glutamate
subunit reagents on adjacent 30-microm sections. The most striking microscopic
abnormalities identified in cresylecht violet stains were cortical
dyslaminations, disoriented neurons, and unexpectedly, very dark Nissl body
staining of those dysplastic neurons. NMDAR2A/B intensely labeled dysplastic
neurons, showing staining in both the cell bodies and dendritic profiles.
However, non-dysplastic neurons were not immunoreactive to NMDAR2A/B. Dysplastic
neurons were also labeled by antibodies selective to NMDAR1. Both dysplastic
neurons and non-dysplastic neurons were immunoreactive to AMPA GluR2/3. Our
results suggest that the epileptic hyperexcitability of dysplastic cortical
regions may result, at least in part, from the heteromeric coassembly and
expressions of NMDAR2A/B subunits with selectively expressed NMDAR1 splice
variants in dysplastic neurons. AMPA receptors are probably also essential but
not sufficient to explain the 'epileptic' properties of these dysplastic neurons.
A longer, detailed report of some of these findings have been previously
published (Ying et al., 1998. J. Neuropathol. Exp. Neurol. 57, 47-62).
PMID- 9761307
TI - Immunocytochemical investigation on dysplastic human tissue from epileptic
patients.
AB - In this report we describe three patients with developmental cortical
abnormalities (generally referred as cortical dysplasia), revealed by MRI and
operated on for intractable epilepsy. Tissue, removed for strictly therapeutic
reasons, was defined as the epileptogenic area by electroclinical data and stereo
EEG (SEEG) recordings. Tissue samples were processed initially for histology, and
selected sections were further processed for immunocytochemical investigation in
order to determine whether the region of cortical dysplasia was co-extensive with
the epileptogenic area. In two patients with nodular heterotopia, disorganized
aggregates of neurons (as revealed by neuronal cytoskeletal markers) were found
within the nodules. Both pyramidal and local circuit neurons were present in the
nodules, but no reactive gliosis was present. When nodules reached the cortex,
the cortical layers were disrupted. In the patient with localized cortical
dysplasia, a complete disorganization of the cortical lamination was found, and
numerous neurons were also present in the white matter. Disoriented pyramidal
neurons weakly labelled with cytoskeletal neuronal markers were also present but
no cytomegalic cells were found. One of the patients with nodular heterotopia
underwent only partial resection of both the 'epileptogenic area' and of the
lesion; this patient still presents with seizures. The other patient with nodular
heterotopia is seizure-free after a complete lesionectomy and excision of the
epileptogenic area. The third patient, with focal cortical dysplasia, had two
surgeries; she became seizure-free only after the excision of the epileptogenic
area detected by SEEG recording. The present data suggest that the dysplastic
areas identified by MRI should not be considered as the only place of origin of
the ictal discharges. From the neuropathological point of view, the focal
cortical dysplasia can be considered as a pure form of migrational disorder.
However, the presence of large aggregates of neurons interspersed within the
white matter, in the subcortical nodular heterotopia, suggests that a defect of
neuronal migration could be associated with an exuberant production of
neuroblasts and/or a disruption of mechanisms for naturally occurring cell death.
PMID- 9761308
TI - Altered connections between neocortical and heterotopic areas in
methylazoxymethanol-treated rat.
AB - We are currently investigating various treatments which could determine, in the
rat brain, structural abnormalities mimicking those reported in human brain
dysgeneses. We can induce the formation of neuronal heterotopia in the progeny of
rats by means of a double injection of the cytotoxic agent methylazoxymethanol
acetate (MAM) on embryonic day 15. We have now investigated the anatomical
connections of these heterotopia by means of anterograde and retrograde tract
tracing techniques. The induced heterotopia along the border of the lateral
ventricles shared common anatomical features with the periventricular nodules in
human periventricular or subcortical nodular heterotopia (PNH). The tract tracing
data demonstrated the existence of reciprocal connections between the neuronal
heterotopia and the ipsilateral and contralateral cortical areas, and the
presence of abnormal cortico-hippocampal and cortico-cortical connections. On the
basis of the connectivity patterns, it may be speculated that some cells in the
heterotopia could be neurons originally committed to the cortex, that were
interrupted in their migration by the MAM treatment. Given the common
morphological features seen in human PNH and MAM-induced brain heterotopia, the
anatomical and developmental analysis of MAM-treated rats may shed light on the
mechanisms by which human brain dysgeneses develop in human patients.
PMID- 9761309
TI - In utero irradiation of rats as a model of human cerebrocortical dysgenesis: a
review.
AB - Certain developmental abnormalities of the cerebral cortex are closely associated
with epilepsy in humans. Exposure of fetal rats to external gamma-irradiation
produces diffuse cortical dysplasia and neuronal heterotopia. These abnormalities
are the result of radiation-induced cell death coupled with continued cortical
development in an altered cellular environment. In vivo electroencephalography
studies in these animals have revealed an increased propensity for electrographic
seizures in the presence of the sedating agents, acepromazine and xylazine. In
vitro neocortical slices containing dysplastic cortex demonstrate enhanced
excitability, as compared to control neocortex, when inhibition that is mediated
by the A-type gamma-amino butyric acid receptor is blocked with bicuculline
methiodide. In utero irradiation of rats produces structural changes that mimic
some aspects of cerebral dysgenesis in humans and results in physiologic changes
that increase the animals' propensity for seizures. Similarities and differences
between the animal model and the human syndromes are discussed.
PMID- 9761310
TI - Excitability changes in freeze-induced neocortical microgyria.
AB - A freezing probe was placed on the skull of postnatal day (PN) 1 rats to induce
formation of a cerebrocortical microsulcus. Experimental studies were performed
on PN days 21-24. At that time point, Nissl-stained sections revealed the
presence of a microsulcus similar to that described in human dysplastic cortex.
Immunocytochemical staining for parvalbumin, calretinin and calbindin indicated a
significant decrease in the number of immunoreactive neurons within the
microsulcus and non-significant decreases in regions adjacent to the microsulcus.
Staining for the glial markers GFAP and vimentin was increased near the
microsulcus. Using in vitro brain slices, recordings were made in cortex adjacent
to the microsulcus. Epileptiform activity was observed in response to electrical
stimulation near the microsulcus. Analysis of the voltage dependence of evoked
epileptiform discharges suggested the presence of an inhibitory component. As
previously observed in non-lesioned animals, bath application of 4-aminopyridine
induced bicuculline-sensitive spontaneous burst discharges in the presence of
excitatory amino acid antagonists. These results suggest that cortical freeze
lesions associated with abnormal neuronal migration produce a chronic
hyperexcitable state. The findings are consistent with a mechanism involving an
alteration, not loss, of inhibition in this model.
PMID- 9761311
TI - Inhibitory function in two models of chronic epileptogenesis.
AB - Although drug-induced disinhibition is a potent method for producing acute
epileptogenesis, data with respect to possible disorders of GABAergic inhibitory
function in models of chronic epilepsy are incomplete and inconsistent. We
examined rat models of cortical post-traumatic epilepsy, and epileptogenic
cortical microgyri. Results suggest enhanced rather than decreased inhibitory
function in cortical networks in these preparations. In brain slices from
epileptogenic chronically isolated cortex, the frequency of spontaneous
inhibitory postsynaptic currents (sIPSCs) and miniature (m)IPSCs in layer V
pyramidal neurons is increased compared to control. In the epileptogenic zone
adjacent to the microgyrus, both spontaneous and stimulus-induced IPSCs are
larger in amplitude than control, and the frequency of sIPSCs is more dependent
upon glutamatergic excitation of interneurons than in control layer V neurons of
homotopic cortex. Immunocytochemical studies show that there is enhanced
immunoreactivity for several proteins in GABAergic interneurons of chronic
cortical isolations, and suggest that there may be sprouting of GABAergic axons
in the area of injury. This conclusion is supported by anatomic data showing an
approximate doubling of the number of presumed inhibitory synapses on somata of
layer V pyramidal neurons. These anatomic findings are consistent with the
increased frequency of mIPSCs on these neurons. Inhibition is robust in both of
these chronic models of epileptogenesis. Increased inhibitory electrogenesis
might be pictured as part of the epileptogenic process, e.g. a mechanism for
synchronizing the discharge of pyramidal neurons, or as a compensatory mechanism
that might prevent the development of abnormal activities in some cases, or limit
the intensity of epileptogenesis in others.
PMID- 9761312
TI - Interneurones are not so dormant in temporal lobe epilepsy: a critical
reappraisal of the dormant basket cell hypothesis.
AB - One axiom at the basis of epilepsy research is that there exists an imbalance
between excitation and inhibition. This abnormality can be achieved by an
increase of excitation on principal cells, a decreased inhibition (i.e.
disinhibition) or both. This review focuses on dysfunction of inhibition, and in
particular on the 'dormant basket cell hypothesis'. This hypothesis states that,
(1) interneurones are functionally disconnected from excitatory afferents,
resulting in hyperexcitability of principal neurones and loss of paired pulse
inhibition, (2) when properly activated, interneurones can still perform their
task, i.e. suppress epileptiform activity and restore paired pulse inhibition.
The aim of this review is to discuss the evidence in support of the 'dormant
basket cell hypothesis'. We will first discuss the rationale underlying the
hypothesis and the criteria needed to validate the hypothesis. We will then show
that, (1) the key experimental data offered in support of the hypothesis
(Bekenstein and Lothman, 1993. Dormancy of inhibitory interneurones in a model of
temporal lobe epilepsy. Science 259, 97-100; Sloviter, 1991. Permanently altered
hippocampal structure, excitability, and inhibition after experimental status
epilepticus in the rat: the 'dormant basket cell' hypothesis and its relevance to
temporal lobe epilepsy. Hippocampus 1, 41-66) are difficult to interpret, and (2)
recent recordings from interneurones in epileptic tissue argue against the
hypothesis. The 'dormant basket cell hypothesis' is then discussed in the broader
context of disinhibition.
PMID- 9761313
TI - 'Dormant' inhibitory neurons: do they exist and what is their functional impact?
AB - The concept of dormant interneurons is proving to be hard to define precisely. We
argue here that the term is best used as an operational description of
interneurons which are not lost from the epileptic brain, but which fail to
perform adequately. We present evidence for the existence of functionally dormant
interneurons in the tetanus toxin model of chronic epilepsy, and we explore the
roles of a partial dormancy (and also of charge-screening) in the acute low
magnesium model of epilepsy.
PMID- 9761314
TI - GABA(A) receptor function in epileptic human dentate granule cells: comparison to
epileptic and control rat.
AB - Using patch clamp recording techniques in dentate granule cells (DGCs) isolated
from patients undergoing temporal lobectomy for intractable epilepsy, we
investigated basic properties of GABA(A) receptors (GABA(A)Rs) and
pharmacological sensitivity of GABA-evoked currents to modulation by zinc and
benzodiazepines (BZ). Properties of human DGC GABA(A)Rs were compared to DGC
GABA(A)R properties in control and epileptic rats. Blockade of GABA evoked
currents by zinc was significantly enhanced in epileptic human relative to
control rat DGCs. Augmentation of the GABA(A)R current by the non-subunit
selective BZ agonist, clonazepam (CNZ) and by the BZ1 specific agonist, zolpidem
(ZOL), were not significantly different in human DGCs relative to control or
epileptic rat. GABA potency was significantly higher in epileptic human DGCs than
in control or epileptic rat DGCs. The significantly enhanced efficacy of zinc in
blocking GABA currents in epileptic human DGCs mirrors that seen in epileptic rat
DGCs, and was coupled with mossy fiber sprouting evident in both epileptic human
and rat dentate gyrus. The aberrant mossy fibers provide a novel zinc delivery
system within the epileptic dentate gyrus. The mossy fiber release of zinc onto
DGCs coupled with the enhanced zinc sensitivity of GABA(A)Rs in epileptic DGCs,
may lead to 'dynamic disinhibition' which could compromise inhibitory efficacy in
the epileptic rat and human hippocampus.
PMID- 9761315
TI - Expression of GABA(A) receptor subunits in the hippocampus of the rat after
kainic acid-induced seizures.
AB - The GABA(A) receptor is a ligand gated chloride channel consisting of five
membrane spanning proteins for which 13 different genes have been identified in
the mammalian brain. The present review summarizes recent work from our
laboratory on the characterization of the immunocytochemical distribution of
these GABA(A) receptor subunits in the rat brain and changes in immunoreactivity
and mRNA expression after kainic acid-induced status epilepticus. A heterogeneous
distribution of immunoreactive GABA(A) receptor subunits was observed. The most
abundant ones were: alpha1, alpha2, alpha4, alpha5, beta2, beta3, gamma2, and
delta. Alpha1, beta2, and gamma2 were about equally distributed in all subfields
of the hippocampus; alpha4- and delta-subunits were preferentially found in the
dentate molecular layer and in CA1; alpha2 was localized to the dentate molecular
layer and CA3; alpha5 was found in the dendritic areas of CA1 to CA3; and beta1
was preferentially seen in CA2. Alpha1, beta2, gamma2 and delta were highly
concentrated in interneurons. Kainic acid-induced seizures caused acute and
chronic changes in the expression of mRNAs and immunoreactive proteins. Acute
changes included decreases in alpha2, alpha5, beta1, beta3, gamma2 and delta mRNA
levels (by about 25-50%), accompanied by increases (by about 50%) in alpha1,
alpha4, and beta2 messages in granule cells (after 6-12 h). Chronic changes,
characterized by losses in mRNA and immunoreactive proteins in CA1 and CA3, are
undoubtedly due to seizure-related cell damage. However, compensatory expression
of alpha2 and beta3 subunits, especially in CA3b/c, was observed. Furthermore,
increases in mRNAs and immunoreactive proteins were seen for alpha1, alpha2
alpha4, beta1, beta2, beta3 and gamma2 in granule cells and in the molecular
layer of the dentate gyrus at 7-30 days after kainic acid injection. The changes
in the expression of GABA(A) receptor subunits, observed in practically all
hippocampal subfields, may reflect altered GABA-ergic transmission during
development of the epileptic syndrome. Increased expression of GABA(A) receptor
subunits in the dendritic field of granule cells and CA3 suggest that GABA-ergic
inhibition may be augmented at these levels. However, the lasting preservation of
alpha1-, beta2-, and gamma2-subunits in interneurons could provide a basis for
augmented inhibition of GABA-ergic interneurons, leading to net disinhibition.
PMID- 9761316
TI - Transcripts of the transposon mariner are present in epileptic brain.
AB - Mobile genetic elements termed transposons have been increasingly implicated in
human disease. The small transposon mariner is widespread within non-vertebrate
genomes and causes mutation by replication, excision, and insertion of itself
without an RNA intermediate. We find that human DNA contains about 60 copies of
this gene. Mariner transcripts are abundant in RNA prepared from sclerotic
epileptic hippocampi. In contrast, typically no mariner-specific RNA is detected
in non-sclerotic hippocampi from other epileptic patients or from autopsies. A
complete but non-functional copy was obtained using rapid amplification of cDNA
ends (RACE). This human mariner transcript is approximately 45% homologous to a
functional counterpart active in Drosophila, with a coding region of 1035 bases
flanked by 32 base inverted terminal repeats. The differential expression of
mariner transcripts within sclerotic hippocampi suggests the probable activity of
an autonomous element which by mutating critical genes could establish an
epileptogenic substrate in the hippocampus.
PMID- 9761317
TI - Hippocampal AMPA and NMDA mRNA levels and subunit immunoreactivity in human
temporal lobe epilepsy patients and a rodent model of chronic mesial limbic
epilepsy.
AB - This study compared temporal lobe epilepsy patients, along with kindled animals
and self sustained limbic status epilepticus (SSLSE) rats for parallels in
hippocampal AMPA and NMDA receptor subunit expression. Hippocampal sclerosis
patients (HS), non-HS cases, and autopsies were studied for: hippocampal AMPA
GluR1-3 and NMDAR1&2b mRNA levels using in situ hybridization: GluR1, GluR2/3,
NMDAR1, and NMDAR2(a&b) immunoreactivity (IR); and neuron densities. Similarly,
spontaneously seizing rats after SSLSE, kindled rats, and control animals were
studied for: fascia dentata neuron densities: GluR1 and NMDAR2(a&b) IR; and neo
Timm's staining. In HS and non-HS cases, the mRNA hybridization densities per
granule cell, as well as molecular layer IR, showed increased GluR1 (relative to
GluR2/3) and increased NMDAR2b (relative to NMDAR1) compared to autopsies.
Likewise, the molecular layer of SSLSE rats with spontaneous seizures
demonstrated more neo-Timm's staining, and higher levels of GluR1 and NMDAR2(a&b)
IR compared to kindled animals and controls. These results indicate that
hippocampal AMPA and NMDA receptor subunit mRNAs and their proteins are
differentially increased in association with spontaneous, but not kindled,
seizures. Furthermore, there appears to be parallels in fascia dentata AMPA and
NMDA receptor subunit expression between HS (and non-HS) epileptic patients and
SSLSE rats. This finding supports the hypothesis that spontaneous seizures in
humans and SSLSE rats involve differential alterations in hippocampal ionotrophic
glutamate receptor subunits. Moreover, non-HS hippocampi were more like HS cases
than hippocampi from kindled animals with respect to glutamate receptors;
therefore, hippocampi from kindled rats do not accurately model human non-HS
cases, despite some similarities in neuron densities and mossy fiber axon
sprouting.
PMID- 9761318
TI - Supragranular mossy fiber sprouting is not necessary for spontaneous seizures in
the intrahippocampal kainate model of epilepsy in the rat.
AB - In a previous study, we suggested a dissociation between spontaneous recurrent
epileptic seizures (SRS) and hippocampal supragranular mossy fiber sprouting
(MFS) in the pilocarpine model of epilepsy (PILO). One possible explanation,
would be that SRS in the PILO model do not originate in the hippocampus and thus
would not depend on MFS. In the present study, we investigated whether MFS is
necessary for the SRS that develop after a small intrahippocampal dose of kainic
acid (KA), a model where seizures are more likely to start in the hippocampus.
Intrahippocampal injections of KA were performed in rats, with and without the
concomitant administration of cycloheximide (CHX) (0.5 microg of KA and 6 microg
of CHX). After injection, recording electrodes were positioned in the same
stereotaxic location. Here again, CHX was able to completely block (5/8 animals)
MFS, visualized by neo-Timm staining, without altering the frequency and
intensity of spontaneous ictal and interictal EEG events. From these data, we can
conclude that, in the intra-hippocampal KA model, MFS is not necessary for the
occurrence of ictal events. We suggest that CHX can be used together with classic
epileptogenic agents, as a means to study temporal lobe epilepsy (TLE) without
the contributing effect of MFS--as seen in TLE patients with mass lesions in the
lateral temporal lobe.
PMID- 9761319
TI - Interaction between superficial layers of the entorhinal cortex and the
hippocampus in normal and epileptic temporal lobe.
AB - The entorhinal cortex (EC) is a major gateway for sensory information into the
hippocampal formation. The information flow from layer II and III of the medial
EC to the hippocampus is regulated in a frequency dependent manner. Spread of low
Mg2+-induced epileptiform activity from EC to hippocampus differs in slices
obtained from normal and kindled rats, and in adult versus juvenile rats. In
slices from normal rats, low Mg2+-induced epileptiform activity in the EC had
only moderate effects on the areas CA3 and CA1, apparently gated by powerful
inhibition in the dentate gyrus. In slices from kindled rats, and from juvenile
rats, there is facilitated propagation of the seizure-like events and late
recurrent discharges through the EC-hippocampal slice. Temporal lobe epilepsy is
associated with selective lesions in layer III of the medial EC. Such loss of
layer III cells of the medial EC during epilepsy may contribute to the
disturbance of frequency dependent information flow from the EC to the
hippocampus, and, therefore, to the cognitive impairments associated with these
disorders.
PMID- 9761320
TI - Functional anatomy of limbic epilepsy: a proposal for central synchronization of
a diffusely hyperexcitable network.
AB - The limbic/mesial temporal lobe epilepsy syndrome has been defined as a focal
epilepsy, with the implication that there is a well defined focus of onset,
traditionally centered around the hippocampus. The pathology of the hippocampus
in this syndrome has been well described and a number of physiological
abnormalities have been defined in this structure in animal models and humans
with epilepsy. However, anatomical and physiological abnormalities have also been
described in other limbic sites in this form of epilepsy. Previous studies have
shown broadly synchronized or multifocal seizure onset within the limbic system
of the animal models and human patients. We hypothesized that the epileptogenic
circuit for the initiation of seizures was distributed throughout the limbic
system with a possible central synchronizing process. In vitro studies showed
that multiple limbic sites in epileptic animals (hippocampus, entorhinal cortex,
piriform cortex and amygdala) have epileptiform changes with prolonged
depolarizations and multiple superimposed action potentials. In vivo studies
revealed that thalamic stimulation yields short latency excitatory responses in
the entorhinal cortex and hippocampus. In addition, in epileptic animals,
thalamic stimulation caused epileptiform responses in the hippocampus. Based on
the findings of this study and on previous anatomy and physiology reports, we
hypothesize that the process of seizure initiation involves broad circuit
interactions involving multiple independent limbic structures, and that the
midline thalamus may act as a physiological synchronizer. We offer a new proposal
for the functional anatomy of limbic epilepsy that takes widespread
hyperexcitability in the limbic system and the potential for thalamic
synchronization into consideration.
PMID- 9761321
TI - Local cerebral glucose utilization in adult and immature GAERS.
AB - In the present study, we compared the basal local cerebral metabolic rates for
glucose (LCMRglcs) both in Wistar rats with genetic absence epilepsy (GAERS:
genetic absence epilepsy rats from Strasbourg) and in control non epileptic (NE)
rats selected in our breeding colony. LCMRglc was measured both in immature rats
at postnatal day 21 (P21) at which age no spontaneous spike-and-wave discharges
can be recorded in GAERS and at the adult age (6 months) when GAERS fully express
thalamo-cortical spike-and-wave discharges recorded on the EEG. LCMRglcs were
measured in 24 structures by the quantitative [14C]2-deoxyglucose
autoradiographic technique. In adults GAERS, LCMRglc underwent a widespread
increase recorded in all brain structures except in mediodorsal and ventromedian
thalamus, and in the nucleus accumbens. These metabolic increases ranged from 17
to 50% over control levels in adult NE rats. In P21 GAERS, LCMRglc was similar to
that of P21 NE rats in 16 areas. It increased over control levels of NE rats in
two groups of structures. Metabolic increases were recorded in four limbic
structures (entorhinal and piriform cortices, hippocampus and basolateral
amygdala) where no spike-and-wave discharges were recorded in adult GAERS.
Increases in LCMRglcs were also located in the substantia nigra pars reticulata,
superior colliculus and globus pallidus which are structures involved in the
control of seizure activity. In conclusion, our data suggest that the
consequences of the genetic mutation(s) underlying the cellular and molecular
events responsible for the expression of spike-and-wave discharges in adult GAERS
is (are) able to increase metabolic activity in both limbic structures and the
nigral inhibitory system before the occurrence of spike-and-wave discharges.
PMID- 9761322
TI - The role of basal ganglia in the control of generalized absence seizures.
AB - During the last two decades, evidence has accumulated to demonstrate the
existence, in the central nervous system, of an endogenous mechanism that exerts
an inhibitory control over different forms of epileptic seizures. The substantia
nigra and the superior colliculus have been described as key structures in this
control circuit; inhibition of GABAergic neurons of the substantia nigra pars
reticulata results in suppression of seizures in various animal models of
epilepsy. The role in this control mechanism of the direct GABAergic projection
from the striatum to the substantia nigra and of the indirect pathway, from the
striatum through the globus pallidus and the subthalamic nucleus, was examined in
a genetic model of absence seizures in the rat. In this model, pharmacological
manipulations of both the direct and indirect pathways resulted in modulation of
absence seizures. Activation of the direct pathway or inhibition of the indirect
pathway suppressed absence seizures through disinhibition of neurons in the deep
and intermediate layers of the superior colliculus. Dopamine D1 and D2 receptors
in the nucleus accumbens, appear to be critical in these suppressive effects.
Along with data from the literature, our results suggest that basal ganglia
circuits play a major role in the modulation of absence seizures and provide a
framework to understand the role of these circuits in the modulation of
generalized seizures.
PMID- 9761323
TI - Spatio-temporal distribution of epileptiform activity in slices from human
neocortex: recordings with voltage-sensitive dyes.
AB - The spatio-temporal distribution of epileptiform activity was investigated in
slices from human temporal neocortex resected during epilepsy surgery. Activity
was recorded by use of a voltage-sensitive dye and an optical recording system.
Epileptiform activity was induced with 10 microM bicuculline and electrical
stimulation of layer I. In 10 slices from six patients investigated, epileptiform
activity spread across most of the slice. Largest amplitudes were located in
layer II/III. Epileptiform activity was characterized by long-lasting potentials
with slow rising phases and a low velocity of spread in the horizontal direction
(0.044 m/s). This spatio-temporal pattern of epileptiform activity in human
slices was similar to that found previously in neocortical slices from guinea
pigs with bicuculline. In four of nine human slices investigated under control
bath conditions (in non-epileptogenic medium), the spatio-temporal activity
patterns were similar to those of guinea pigs in non-epileptogenic medium. In the
remaining five human slices, however, the spread in the horizontal direction was
significantly larger (4188 microm) in non-epileptogenic medium than that found in
slices from guinea pigs (2171 microm). Activity in human slices showing such
'wide spread' in control bath conditions occasionally had characteristic features
of epileptiform activity. Further work will have to clarify whether these
epileptiform features reflect intrinsic epileptiform properties in human tissue
slices.
PMID- 9761324
TI - Amygdala damage in experimental and human temporal lobe epilepsy.
AB - The amygdala complex is one component of the temporal lobe that may be damaged
unilaterally or bilaterally in children and adults with temporal lobe epilepsy
(TLE) or following status epilepticus. Most MR (magnetic resonance) imaging
studies of epileptic patients have shown that volume reduction of the amygdala
ranges from 10-30%. In the human amygdala, neuronal loss and gliosis have been
reported in the lateral and basal nuclei. Studies in rats have more specifically
identified the amygdaloid regions that are sensitive to status epilepticus
induced neuronal damage. These areas include the medial division of the lateral
nucleus, the parvicellular division of the basal nucleus, the accessory basal
nucleus, the posterior cortical nucleus, and portions of the anterior cortical
and medial nuclei. Otherwise, other amygdala nuclei, such as the magnocellular
and intermediate divisions of the basal nucleus and the central nucleus, remain
relatively well preserved. Amygdala kindling studies in rats have shown that the
density of a subpopulation of GABAergic inhibitory neurons that also contain
somatostatin may be reduced even after a low number of generalized seizures.
While analyses of histological sections and MR images indicate that in
approximately 10% of TLE patients, seizure-induced damage is isolated to the
amygdala, more often amygdala damage is combined with damage to the hippocampus
and/or other brain areas. Moreover, recent data from rodents and nonhuman
primates suggest that structural and functional alterations caused by seizure
activity originating in the amygdala are not limited to the amygdala itself, but
may also affect other temporal lobe structures. The information gathered so far
on damage to the amygdala in epilepsy or after status epilepticus suggests that
local alterations in inhibitory circuitries may contribute to a lowered seizure
threshold and greater excitability within the amygdala. Furthermore, damage to
select nuclei in the amygdala may predict impairment of performance in behavioral
tasks that depend on the integrity of the amygdaloid circuits.
PMID- 9761325
TI - Antiepileptic effects of allopurinol on EL mice are associated with changes in
SOD isoenzyme activities.
AB - We have investigated the potential antiepileptic action of superoxide dismutase
(SOD) activities in the brain of the epileptic mutant EL mouse. EL mice which
experienced frequent seizures (EL[s]) had abnormally low levels of SOD isoenzyme
activity in the hippocampal area. Once epileptogenicity was established in these
animals, activity of cyanide-sensitive Cu,Zn-SOD was maintained at significantly
lower levels than in control mice. However, cyanide-insensitive Mn-SOD activity
was not different from non-epileptic controls. In EL mice which had not
experienced seizure provoking stimulations and exhibited no seizures (EL[ns])
there was moderately lower levels of SOD isoenzyme activities compared to
controls. In spite of the low level of Cu,Zn-SOD activity in EL[s] mice, the
Cu,Zn-SOD protein content was high in the hippocampus of these animals,
suggesting that inactive Cu,Zn-SOD might be induced during development. After
allopurinol (ALP) was given orally to EL[s] mice, Cu,Zn-SOD activities increased
dramatically in the hippocampus and seizure activity was decreased. Even after 48
h, when antiepileptic action of ALP was lost, the SOD activity was maintained at
the high level associated with initial ALP administration. EL[s] mice also showed
DNA fragmentation in the hippocampal CA1 region and the parietal cortex, detected
with in situ terminal transferase-mediated dUTP nick labeling with the aid of
alkaliphosphatase or peroxidase. The degree of DNA fragmentation was less severe
in EL[ns] mice. We propose that abnormalities in region specific Cu,Zn-SOD
isoenzyme activity might produce free radicals, leading to DNA fragmentations and
cell loss. This might contribute to hippocampal epileptogenesis in EL mice.
PMID- 9761326
TI - Hormonal and gestational parameters in female rats submitted to the pilocarpine
model of epilepsy.
AB - Endocrine and reproductive alterations are frequently reported to occur in women
with temporal lobe epilepsy as well as in female rats in different experimental
models of limbic seizures. As previously reported, women with epilepsy have lower
fertility rates than women without epilepsy (Tanganelli, P., Regesta, G., 1992.
Neurology (suppl.) 42 (5), 89-93; Cummings, L.N., Guidice, L., Morrel, M.J.,
1995. Epilepsia 36, 355-359). In order to investigate the possible substrate of
endocrine alterations in epilepsy, hormonal and gestational parameters were
studied in female rats submitted to the pilocarpine model of epilepsy. The
results demonstrated that the oestrus cycle is altered following pilocarpine
induced status epilepticus and such alteration lasted for several weeks.
Progesterone, LH and FSH levels decreased and estradiol levels increased
significantly during the period of spontaneous and recurrent seizures. The
frequency of seizures during pregnancy and lactation decreased. These results
document that significant changes in gonadal, hypophyseal and hypothalamic
hormones, as well as in sexual behaviour, occur following status epilepticus
induced by pilocarpine administration.
PMID- 9761327
TI - Osmolarity, ionic flux, and changes in brain excitability.
AB - The majority of modern epilepsy research has focused on possible abnormalities in
synaptic and intrinsic neuronal properties--as likely epileptogenic mechanisms as
well as the targets for developing novel antiepileptic treatments. However, many
other processes in the central nervous system contribute to neuronal excitability
and synchronization. Regulation of ionic balance is one such set of critical
processes, involving a complex array of molecules for moving ions into and out of
brain cells--both neurons and glia. Alterations in extracellular-to-intracellular
ion gradients can have both direct and indirect effects on neuronal discharge. We
have found, for example, that when hippocampal slices are exposed to hypo-osmotic
bathing medium, the cells not only swell, but there is also a significant
increase in the amplitude of a delayed rectifier potassium current in inhibitory
interneurons--an effect that may contribute to the increase in tissue
excitability associated with hypo-osmolar treatments. In contrast, antagonists of
the chloride co-transporter, furosemide or bumetanide, block epileptiform
activity in both in vitro and in vivo preparations. This antiepileptic effect is
presumably due to the drugs' ability to block chloride co-transport. Indeed,
prolonged tissue exposure to low levels of extracellular chloride have a parallel
action. These experiments indicate that manipulation of ionic balance may not
only facilitate epileptiform activities, but may also provide insight into new
therapeutic strategies to block seizures.
PMID- 9761328
TI - Properties of human glial cells associated with epileptic seizure foci.
AB - We studied physiological properties of glial cells from acute slices of biopsies
from patients operated for intractable mesio-temporal lobe epilepsy using whole
cell patch-clamp recordings. Cells were filled with Lucifer Yellow (LY) during
recordings to allow morphological reconstruction and immunohistochemical cell
identification. Seizure-associated astrocytes had complex, arborized, highly
branched processes giving them a stellate appearance, and cells stained intensely
for the intermediate filament GFAP as previously reported for 'reactive'
astrocytes. GFAP-positive astrocytes from epilepsy biopsies consistently
expressed voltage-activated, TTX-sensitive Na+ channels that showed fast
activation and inactivation kinetics. Unlike comparison astrocytes, derived from
tissues that were not associated with seizure foci, these astrocytes expressed
Na+ channels at densities sufficient to generate slow action potentials (spikes)
in current clamp studies. In these cells, the ratio of Na+ to K+ conductance was
consistently 3-4-fold higher than in comparison human or control rat astrocytes.
Four of 17 astrocytes from epilepsy patients versus 14/14 from control rat
hippocampus and four of five in comparison human tissue showed a lack of inwardly
rectifying K+ currents, which in normal astrocytes are implicated in the control
of extracellular K+ levels. These results suggest that astrocytes surrounding
seizure foci differ in morphological and physiological properties, and that glial
K+ buffering could be impaired at the seizure focus, thus contributing to the
pathophysiology of seizures.
PMID- 9761329
TI - Valproate selectively reduces the persistent fraction of Na+ current in
neocortical neurons.
AB - The effect of valproate (VPA) on Na+ currents (INa), was studied by means of
voltage clamp recordings using whole-cell patch clamp configuration in 21 acutely
dissociated neocortical neurons. Concentrations of VPA up to 200 microM failed to
induce any detectable decrease in fast INa (I(Naf)), but the persistent fraction
(I(NaP)) was significantly reduced by low VPA concentrations (10-30 microM),
corresponding to the lower values of the 'therapeutic' range in epileptic
patients. Since it is known that I(NaP) critically regulates the firing
properties of pyramidal neurons, it is suggested that the anticonvulsant
effectiveness of VPA is mainly due to its effect on I(NaP).
PMID- 9761330
TI - Effect of valproic acid on sodium currents in cortical neurons from patients with
pharmaco-resistant temporal lobe epilepsy.
AB - In a selected group of temporal lobe epilepsy patients with seizures refractory
to pharmacological treatment, pharmacological seizure control can be attained by
surgical resection of the epileptic zone. We investigated to what extent pharmaco
resistance is reflected in a reduced response at the cellular level, in neurons
acutely isolated from the temporal cortex resected in 20 patients. We studied the
effect of valproic acid (VPA) on the transient sodium current, measured under
whole-cell voltage-clamp conditions. We compared neurons from patients with
temporal lobe sclerosis (S) with neurons from patients without hippocampal
sclerosis (nS) and compared hippocampal CA1 neurons (CA) with neocortical neurons
(NC). We could not detect differences in the voltage dependence and kinetics of
sodium current activation and inactivation in any of the group comparisons. VPA
shifted the voltage dependence of steady-state inactivation (expressed as V(h,i)
in a Boltzmann fit) to more hyperpolarized levels. The shift induced by 2 mM VPA
was -5.1 +/- 0.7 mV in CA-S (n = 13), -5.1 +/- 0.7 mV in CA-nS (n = 25), -4.3 +/-
0.5 mV in NC-S (n = 17) and -4.9 +/- 0.5 mV in NC-nS (n = 16) The relation
between concentration and voltage shift had an EC50 of 1.4 +/- 0.2 mM VPA (n =
16) and a maximal shift of 9.6 +/- 0.9 mV. We conclude that pharmaco-resistance
in these patients is not associated with a changed modulation of the sodium
current by VPA. Results are discussed in the light of a reduced sodium current
modulation by carbamazepine in CA1 neurons of patients with hippocampal sclerosis
and of similar observations in the kindling model of epileptogenesis.
PMID- 9761331
TI - Voltage-dependent Ca2+ currents in epilepsy.
AB - Voltage-dependent Ca2+ channels (VCCs) represent one of the main routes of Ca2+
entry into neuronal cells. Changes in intracellular Ca2+ dynamics and homeostasis
can cause long-lasting cellular changes via activation of different Ca2+
dependent signalling pathways. We have investigated the properties of VCCs in
human hippocampal dentate granule cells (DGCs) using the whole-cell configuration
of the patch-clamp method. Classical high-threshold Ca2+ currents were composed
mainly of omega-CgTx-sensitive N-type and nifedipine-sensitive L-type currents
that were present in similar proportions. In addition, a Ca2+ current component
that was sensitive to low concentrations of Ni2+, but not to nifedipine or omega
conotoxin GVIA (omega-CgTx GVIA) was present. This latter component showed a half
maximal inactivation at more hyperpolarized potentials than high-threshold
currents and a more rapid time-dependent inactivation. This current was termed T
type Ca2+ current. Current components with similar pharmacological and kinetic
characteristics could be elicited in acutely isolated control rat DGCs. The
current density of high threshold and T-type Ca2+ components was significantly
larger in human DGCs and in the kainate model compared to DGCs isolated from
adult control rats. These differences in current density were not accompanied by
parallel differences in the voltage-dependence of VCCs. Taken together, these
data suggest that an up-regulation of Ca2+ current density may occur in
hippocampal epileptogenesis without consistent changes in Ca2+ current
properties.
PMID- 9761333
TI - Effect of nisin on heat injury and inactivation of Salmonella enteritidis PT4.
AB - The ability of heat injury to confer sensitivity to nisin in a Gram negative
pathogen was investigated. Injury and inactivation kinetics of Salmonella
enteritidis PT4 in the presence of nisin were determined in media, liquid whole
egg and egg white using cultural methods and capacitance monitoring to detect
injury. Addition of nisin in concentrations from 500 IU/ml to 2500 IU/ml in the
heating menstruum caused a reduction of required pasteurisation time of up to
35%, principally as a result of its effect on cells suffering damage during
heating. In egg white and liquid whole egg the organism's heat susceptibility was
greater than in nutrient broth, particularly in egg white which contained no fat
and had an alkaline pH. The effect of nisin on heat susceptibility was however
less pronounced than in nutrient broth due to its interaction with protein and
fat. Though nisin did not enhance the lethality of heat processes, injury is more
severe in egg white containing nisin, presumably as a result of its interaction
with antimicrobial factors in egg white.
PMID- 9761332
TI - Type E botulism associated with vacuum-packaged hot-smoked whitefish.
AB - On January 16, 1997 two Germans got botulism after eating hot-smoked Canadian
whitefish produced in Finland. The serum sample of one of the patients contained
6 MLD/ml of botulinum toxin. The type of toxin was identified as E by the toxin
neutralization test and the botulinum neurotoxin type E (BoNT/E) gene was also
amplified from the serum by polymerase chain reaction (PCR), but C. botulinum
could not be isolated from the positive serum sample. The remains of the hot
smoked whitefish eaten by the patients contained botulinum toxin detected by the
mouse bioassay and the BoNT/E gene as determined by PCR. C. botulinum was
isolated from the fish sample and it was confirmed to be type E by the mouse
bioassay and by PCR. Eleven other fish samples from the same lot did not contain
botulinum toxin nor any BoNT gene. The incriminated food was processed on the 9th
and 10th of January, 1997 from frozen whitefish imported to Finland from Canada.
The pulsed-field gel electrophoretic pattern of the isolated C. botulinum strain
resembled a reference strain of North American origin. It did not match any C.
botulinum strains isolated from the Baltic sea-bottom or from the fish caught in
the area indicating that the fish was contaminated by C. botulinum in Canada. The
conditions resulting in toxin production could not be identified. The safety
problems associated with vacuum-packaged hot-smoked fish seem to be of utmost
concern and the product is one of the most important botulism food vehicles
processed on an industrial scale. Temperature monitoring and the use of time
temperature indicators are to be recommended in order to ensure adequate storage
temperature from processing through to consumption. Allowing the use of nitrate
and nitrite together with sufficiently high NaC1 concentration in this particular
product should also be considered.
PMID- 9761334
TI - Combined effect of nisin and high hydrostatic pressure on destruction of Listeria
innocua and Escherichia coli in liquid whole egg.
AB - High hydrostatic pressure inactivation of Escherichia coli and Listeria innocua
inoculated in liquid whole egg was improved significantly (P < 0.05) with nisin
addition at concentrations of 1.25 and 5 mg/1. A reduction of almost 5 log10
units in E. coli counts and more than 6 log10 units for L. innocua was obtained
at 450 MPa and 5 mg/l of nisin. For this treatment, the two microorganisms were
not detectable after 1 month of storage at 4 degrees C. The amount of nisin added
did not affect E. coli inactivation at 300 MPa. For L. innocua, 5 mg/l of nisin
was more effective than 1.25 mg/l. Nisin showed no effect when samples were
stored at 20 degrees C after pressurization, except for samples with L. innocua
containing 5 mg/l of nisin and treated with 450 MPa.
PMID- 9761335
TI - The combined affects of modified atmosphere, temperature, nisin and ALTA 2341 on
the growth of Listeria monocytogenes.
AB - A cocktail of seven Listeria monocytogenes isolates of food, human and
environmental origin was used to assess the antilisterial activity of the
bacteriocins nisin and ALTA 2341 in combination with various atmospheres: air,
100% N2, 40% CO2:60% N2, or 100% CO2. Buffered tryptone soya broth (pH 6.0) was
used as the growth medium and incubation was at 4 degrees C (21 days) or 12
degrees C (7 days), or when temperature fluctuated between these values for
defined periods. It was observed that atmosphere alone influenced the growth rate
of L. monocytogenes, with 100% CO2 exerting the greatest inhibition. A 5 log
population increase was observed in all atmospheres after 7 days at 12 degrees C.
At 4 degrees C a 4-5 log population increase was observed in air, 100% N2 and 40%
CO2:60% N2 within 21 days. Growth was prevented by 100% CO2. In the presence of
nisin (400 IU/ml), an increase in the lag phase was observed before growth (5 log
population increase after 7 days) in all atmospheres at 12 degrees C. This effect
was enhanced at 4 degrees C where a maximum 2 log population increase was
observed in all atmospheres except 100% CO2, in which growth was prevented.
Increasing the concentration of nisin to 1250 IU/ml prevented L. monocytogenes
growth in all atmosphere combinations at 4 and 12 degrees C. Two concentrations
of ALTA 2341 were also tested. In the presence of 0.1% ALTA 2341 and at 12
degrees C, a 3-5 log population increase was observed in all atmospheres with the
exception of 100% CO2, which prevented L. monocytogenes growth. At 4 degrees C,
growth was observed in the combination of 0.1% ALTA 2341 and 100% N2 only (3 log
population increase). Use of a higher concentration of ALTA 2341 (1.0%) resulted
in a population decrease below the detection level within 24 h in all
atmosphere/temperature combinations. Re-growth occurred in the presence of 1.0%
ALTA 2341 in all atmospheres at 12 degrees C, and in combination with air or 100%
N2 at 4 C. When the effectiveness of either nisin or ALTA 2341 and atmosphere was
tested against L. monocytogenes as temperature fluctuated for periods between 4
and 12 degrees C, only the combination of 100% CO2 and 1.0% ALTA 2341 prevented
growth. Cells surviving exposure to nisin or ALTA 2341 were recovered from 28 of
the 32 combinations tested that contained bacteriocin. Nisin survivors remained
sensitive to the bacteriocin. ALTA 2341 survivors had become resistant to the
bacteriocin.
PMID- 9761336
TI - The antimicrobial activity of acidocin CH5 in MRS broth and milk with added NaCl,
NaNO3 and lysozyme.
AB - The ability of acidocin CH5, a bacteriocin from Lactobacillus acidophilus CH5 in
the form of neutralized and heated supernatant, to prevent the growth of the
indicator Lactobacillus delbrueckii subsp. lactis LTI 30 alone or together with
other antimicrobials was investigated. The inhibitory activity of acidocin CH5
was higher in MRS broth than in reconstituted skim milk (RSM). In MRS broth and
RSM, 1.92 and 32 AU acidocin CH5/ml, respectively, caused 97 and 89% inhibition
of the indicator Lactobacillus delbrueckii subsp. lactis LTI 30. The presence of
5 and 10% milk fat in RSM decreased the inhibitory activity of acidocin CH5 to 20
and 11%, respectively. The inhibitory activity of acidocin CH5 was also reduced
in the presence of NaCl, NaNO3 and lysozyme. In RSM the inhibition was weaker
with both acidocin CH5 and NaCl added compared with NaCl alone. In MRS broth the
inhibition was stronger with both acidocin CH5 and NaCl added compared with NaCl
alone. The inhibition of the indicator Lactobacillus delbrueckii subsp. lactis
LTI 30 was stronger with both NaNO3 and acidocin CH5 in MRS broth (but not in
RSM) than with only NaNO3 present, but the strongest level was obtained with
acidocin CH5 alone. Addition of acidocin CH5 and more than 30 mg/ml lysozyme to
MRS broth increased the level of inhibition above the level obtained by acidocin
CH5 alone. The indicator Lactobacillus delbrueckii subsp. lactis LTI 30 was also
sensitive to NaCl, NaNO3 and lysozyme in both MRS broth and RSM.
PMID- 9761337
TI - A novel modelling approach for predicting microbial growth in a raw cured meat
product stored at 3 degrees C and at 12 degrees C in air.
AB - To predict microbial growth during chill storage of a traditional Greek raw
sausage, a numerical model was developed and validated. In our novel approach,
the specific growth rate of each microbial population was calculated on the basis
of the main microbial populations grown in the sausage. In addition, the specific
destructive effect of the sausage ecosystem was introduced to evaluate microbial
growth. The model was integrated by the Runge-Kutta method and the parameter
values were optimised by the least squares method. Fitting of the model to the
experimental data derived from four sausage batches stored aerobically at 3 and
12 degrees C successfully described the microbial growth kinetics in the sausage
niche. Finally, the parameter values estimated by the fitting of the model on the
data set from each batch were used to predict microbial growth in the other
batches at both storage temperatures.
PMID- 9761338
TI - Molecular characterization of the Lactobacillus community in traditional
processing of Mozzarella cheese.
AB - The natural Lactobacillus community involved in traditional Mozzarella cheese
production has been investigated. The bacterial associations of whey, curd before
stretching and Mozzarella were analyzed using randomly amplified polymorphic DNA
(RAPD) to follow growth kinetics, and 16S rDNA sequencing to identify the
taxonomical position of isolated strains. Analysis of RAPD fingerprints revealed
that the Lactobacillus community was composed of 13 different biotypes and the
sequence analysis of 16S rDNA demonstrated that the isolated strains belong to L.
plantarum, L. fermentum, L. helveticus and L. casei subsp. casei. In addition,
two strains of Weissella hellenica were isolated on selective media for
lactobacilli. The four L. casei subsp. casei strains and W. hellenica contained
sequences related to the prtP gene coding for proteinase, and the highest
proteolytic activity in milk was found in one strain of L. casei subsp.casei.
PMID- 9761339
TI - Comparison of five typing methods for the epidemiological study of Listeria
monocytogenes.
AB - Five typing methods were compared in a study designed to adapt a strategy for
epidemiologically typing large numbers of Listeria monocytogenes strains. The
methods studied were serotyping, electrophoretic typing of esterases
(zymotyping), restriction fragment length polymorphism of ribosomal DNA
(ribotyping), random amplified polymorphic DNA (RAPD) and pulsed-field gel
electrophoresis (PFGE). Data were analysed by computer-assisted statistical
analysis. Included in the analysis were 35 strains of L. monocytogenes, including
14 epidemic strains isolated during outbreaks in France in 1992 and 1993, and 21
strains isolated from food and the environment. Five serotypes, eight zymotypes,
ten ribotypes, 13 RAPD patterns and 12 PFGE patterns were identified among the 35
strains. The most discriminating combination of typing methods was ribotyping and
PFGE typing [27 types, discriminatory index (D.I.) = 0.978]. A factorial analysis
of correspondence for each method differentiated the epidemic strains from the
environmental strains. This study shows that computer-assisted statistical
treatment of the data, combined with the use of discriminating typing methods, is
a powerful tool for the epidemiological analysis of Listeria monocytogenes.
PMID- 9761340
TI - Relationship between volatile components of citrus fruit essential oils and
antimicrobial action on Penicillium digitatum and penicillium italicum.
AB - This study examined the effect of volatile components of citrus fruit essential
oils on P. digitatum and P. italicum growth. The hydrodistilled essential oils of
orange (Citrus sinensis cvv. "Washington navel", "Sanguinello", "Tarocco",
"Moro", "Valencia late", and "Ovale"), bitter (sour) orange (C. aurantium),
mandarin (C. deliciosa cv. "Avana"), grapefruit (C. paradisi cvv. "Marsh
seedless" and "Red Blush"), citrange (C. sinensis x Poncirus trifoliata cvv.
"Carrizo" and "Troyer"), and lemon (C. limon cv. "Femminello", collected in three
periods), were characterized by a combination of GC and GC/MS analyses. The
antifungal efficacy of the oils was then examined at progressively reduced rates.
Findings showed a positive correlation between monoterpenes other than limonene
and sesquiterpene content of the oils and the pathogen fungi inhibition. The best
results were shown by the citrange oils, whose chemical composition is reported
for the first time, and lemon. Furthermore P. digitatum was found to be more
sensitive to the inhibitory action of the oils.
PMID- 9761341
TI - Molecular epidemiology of Salmonella serotype Enteritidis. Relationships between
food, water and pathogenic strains.
AB - A molecular epidemiology study of Salmonella serotype Enteritidis was carried out
by ribotyping performed with a mixture of PstI and SphI (PS ribotyping), and
randomly amplified polymorphic DNA (RAPD) typing conducted with the OPB17 primer.
A series, including 38 food and 25 water strains, which were epidemiologically
unrelated and collected in Spain over 1985-1996, was differentiated into 20 PS
ribotypes [discrimination index (DI) = 0.67], RAPD types (DI = 0.28), and by
combining both methods into 23 genomic groups (DI = 0.76). With ribotyping data
from the strains tested in this and in a previous work, including clinical and
reference strains, a similarity dendrogram was traced and the subsequent branches
and groupings were correlated with RAPD types, phage types and sources of origin.
At a similarity level of 55%, a major cluster (grouping five subclusters and
three single branches) and two minor clusters were revealed. Results supported
the fact that organisms representing, at least, 40 genomic groups are currently
circulating in Spain, but that only the organisms of five groups predominate and
these fall into a single subcluster or lineage. Organisms of these five groups
could be considered endemic, associated with food-borne human infections and, for
epidemiological purposes, can be differentiated by phage typing. The most
frequent phage types can be subdivided into genomic groups. Organisms of the
prevalent genomic groups and several less frequent ones were mainly associated
with poultry transmission and gastroenteritis as the major clinical forms, while
organisms of another two frequent groups were mainly associated with extra
intestinal infections, and organisms of four infrequent groups were only
collected from sewage or environmental waters.
PMID- 9761342
TI - A collaborative study on media for the enumeration of yeasts in foods.
AB - A collaborative study was made to evaluate the effectivity of a general purpose
medium, tryptone glucose yeast extract (TGY) agar on the detection and
enumeration of yeasts from food. Nine laboratories participated in the study and
compared five media (four kinds of TGY with different concentrations of glucose,
one of them without tryptone, and, for comparison, dichloran rose bengal
chloramphenicol (DRBC) agar). Six food samples were investigated by each
laboratory and 23 additional food samples were investigated individually by
different laboratories. No difference was found in the performance of media with
either the samples common to all laboratories or the various samples tested in
different ones. A medium consisting of tryptone, glucose and yeast extract, at
any concentration of glucose tested, appeared reliable for the detection and
enumeration of yeasts from foods, and its performance did not differ from that of
DRBC. Omission of tryptone as recommended by ISO provided an even simpler medium
of equally good performance. TGY without chloramphenicol may result in higher
total counts due to the development of bacteria. DRBC incubated in light results
in lower counts compared to that incubated in the dark.
PMID- 9761343
TI - Relation between the generation time and the lag time of bacterial growth
kinetics.
AB - In predictive microbiology, the relation between the lag time (Lag) and the
generation time (Tg) is commonly assumed to be proportional, as long as the pre
incubation environmental conditions remain constant. This relation was
statistically examined in nine published datasets. For every dataset, it was
roughly proportional. However, a more advanced study showed that the ratio Lag/Tg
was not totally independent of the environmental conditions. In particular, a
significant negative effect of the pH on this ratio was observed in five of the
nine datasets. For modeling the environmental dependence of microbial growth
parameters, some authors independently deal with Lag and Tg. Other authors only
model the environmental dependence of Tg, assuming Lag/Tg to be constant. These
two modeling methods were statistically compared for the nine datasets under
study. Results differed from one dataset to another. For some, the model
developed with a constant ratio Lag/Tg sufficed to describe the data, whereas for
the others, an independent modeling of Lag and Tg was more satisfactory.
PMID- 9761344
TI - Concentration of carbon dioxide in the water-phase as a parameter to model the
effect of a modified atmosphere on microorganisms.
AB - The effect of modified atmosphere packaging can mainly be attributed to the
bacteriostatic action of CO2. The dissolved CO2 in the water-phase of a food
product is strongly dependent on several intrinsic and extrinsic parameters and
will determine the effectiveness of a modified atmosphere packaging
configuration. The effect of pH, gas/product ratio, initial %CO2 in the gas
phase, lard content and storage temperature on the amount of dissolved CO2 was
screened in a preliminary experiment. The initial CO2-concentration in the gas
phase and the gas/product ratio turned out to be the two major factors
determining the amount of dissolved CO2. The initial pH also determined
significantly the final CO2-concentration in the broth. Temperature and lard
content were shown to have only a minor effect on the amount of dissolved CO2
compared to the above mentioned parameters. This demonstrates the importance of
the packaging configuration in the effectiveness of a modified atmosphere. In a
second step, a model was constructed to predict the amount of dissolved carbon
dioxide in modified BHI-broth as a function of the gas/product ratio, the initial
CO2-concentration and the temperature by means of Response Surface Methodology
(RSM). A second equation was also derived based on Henry's law and was shown to
be a powerful tool in the quantification of the effect of intrinsic and extrinsic
parameters on the CO2-solubility in food products. The possibility of the use of
the concentration of dissolved CO2 in the water-phase as a determinative factor
for the inhibitory effect of modified atmospheres was examined on Pseudomonas
fluorescens. Growth curves at 7 degrees C of P. fluorescens in different
packaging configurations (initial %CO2 and gas/product ratio) resulting in equal
amounts of dissolved CO2 were compared. P. fluorescens was shown to be similarly
inhibited by equal amounts of dissolved CO2-concentrations, independent of the
packaging configuration. This demonstrates the potential of the application of
the concentration of dissolved CO2 in the water-phase as a parameter to
characterise a modified atmosphere and its inhibition of certain microorganisms.
PMID- 9761345
TI - Microbial populations associated with commercially produced South African sorghum
beer as determined by conventional and Petrifilm plating.
AB - Microbial populations of 46 commercially produced sorghum beer samples from
retail outlets in Johannesburg, South Africa, were enumerated and characterized.
Aerobic plate counts, lactic acid bacteria counts and yeast counts were performed
by conventional and Petrifilm plating. Conventional methods yielded yeast counts
of 7.84 log CFU/ml, lactic acid bacteria counts of 6.44 log CFU/ml and aerobic
plate counts of 5.96 log CFU/ml. In comparison, Petrifilm counts were 7.85 log
CFU/ml for yeasts, 5.31 log CFU/ml for lactic acid bacteria and 5.34 log CFU/ml
for aerobic bacteria. Characterization of 419 predominant bacterial isolates from
Standard One Nutrient Agar, MRS Agar and corresponding Petrifilm plates yielded
88.0% lactic acid bacteria, 8.4% Bacillus species, 2.9% Micrococcus species and
0.7% Gram negative bacteria. Composition of predominant lactic acid bacteria
populations from Standard One Nutrient Agar and both types of Petrifilm plates
showed marginal differences. Increased proportions of heterofermentative lactic
acid bacteria were, however, isolated from conventional MRS Agar compared to the
modified Petrifilm product which represented the equivalent to MRS Agar.
PMID- 9761346
TI - A novel, selective synthetic acetamide containing culture medium for isolating
Pseudomonas aeruginosa from milk.
AB - A selective synthetic medium has been developed both in liquid (Z-broth) and
solid (Z-agar) forms for selective isolation of Pseudomonas aeruginosa from
foods. The simple, easy to prepare peptone-free synthetic medium contained
acetamide that is metabolized to ammonia and acetic acid providing nitrogen and
carbon supply. The medium contained no inhibitors. Selectivity of the liquid
medium was tested by inoculation of pure cultures of different bacteria belonging
to the groups Bacillus, Pseudomonas, Enterobacteriaceae and Staphylococcus. It
was found that the selectivity of the medium was complete for the examined range
of bacteria. However, a similar result was obtained when nitrofurantoin broth was
used. Applicability of the synthetic agar medium was also tested by a nation-wide
inter-laboratory test using two milk samples containing 10(3)/ml (sample I) and
10(5)/ml (sample II) Pseudomonas aeruginosa. According to this test, no
microbiologically relevant differences were found between the results obtained by
Z-agar and cetrimide-agar a frequently used selective agar in case of sample II.
However, a relevant and statistically significant difference was found in the
results of sample I in favour of the Z-agar, that could indicate the presence of
a low number of bacteria. Concerning repeatability and reproducibility, Z-agar
proved to be superior to cetrimide agar.
PMID- 9761347
TI - Bacteriocin production and competitiveness of Lactobacillus plantarum LPCO10 in
olive juice broth, a culture medium obtained from olives.
AB - A culture medium, named olive juice broth, which resembles the natural
environment of Lactobacillus plantarum in the traditional Spanish-style green
olive fermentation was obtained from green olives. In this medium, the
bacteriocin-producing L. plantarum LPCO10 strain was able to produce bacteriocin
throughout the incubation time (15 days). Bacteriocin purification from olive
juice broth was achieved by a protocol including ammonium sulphate precipitation
of cell-free, L. plantarum LPCO10 culture supernatants, and cation-exchange,
hydrophobic-interaction and reversed-phase chromatographies. In a series of mixed
cultures in olive juice broth, L. plantarum LPCO10 was able to dominate the
bacteriocin-sensitive L. plantarum 128/2 strain, whereas the non-bacteriocin
producing, LPCO10 strain derivative, L. plantarum 55-1 strain did not show such
capability. These results indicated that olive juice broth may be a valuable
experimental substitute for olive fermentation brine in gaining more knowledge
about the role of the bacteriocin-producing L. plantarum strains in the control
of the Spanish-style green olive fermentation.
PMID- 9761348
TI - Mathematical modeling to predict the bactericidal effect of processed vinegar on
Escherichia coli O157:H7.
AB - The combined effects of acetic acid, temperature and sodium chloride on
Escherichia coli O157:H7 inactivation were examined in processed vinegar. To
express their effects, quadratic polynomial models were applied. The logarithm
transformation of sodium chloride concentration provided a better fit of the data
than the use of a non-transformation value. On the basis of this finding, the
polynomial models should be distinguished into two types, i.e. the non-sodium
chloride model and the sodium chloride model, both of which had high R2 values
(0.988 and 0.978, respectively).
PMID- 9761349
TI - Impact of recurrent nephrotic syndrome after renal transplantation in young
patients.
AB - Recurrent disease is a frequent complication of patients transplanted for steroid
resistant nephrotic syndrome associated with focal segmental glomerulosclerosis.
Its long-term prognosis has rarely been studied. We examined 39 patients aged 4
25 (mean 13.5) years at the time of first transplantation (TX). Twelve of these
(30%) developed nephrotic syndrome after the first TX and 2 of 8 after the second
TX. The mean observation period from first TX to last observation with a
functioning graft or graft loss was 5.4 (0.1-19.3) years. We confirmed that
recurrent disease is associated with older age at onset of the primary disease,
shorter time from onset to end-stage renal disease, and diffuse mesangial
proliferation in the initial kidney biopsy. Remissions occurred in all 3 children
undergoing early repeated plasma exchange and in 1 adolescent following
introduction of cyclosporin A 7 years after TX. At last observation 42% of
relapsing and 48% of non-relapsing patients with a similar follow-up period had a
functioning first graft. Median first graft survival was almost identical in the
relapsing and the non-relapsing patients (4.3 vs. 4.2 years). Histological
lesions of focal glomerulosclerosis were detected in the posttransplant biopsies
of only 3 patients. In conclusion, young patients with nephrotic syndrome
associated with focal segmental sclerosis have a similar graft survival with and
without recurrence of the nephrotic syndrome.
PMID- 9761350
TI - Comparable renal graft survival in African-American and Caucasian recipients.
AB - In past years, many pediatric transplant centers found African-American renal
transplant recipients to have poor graft survival. Since 1991 anti-lymphocyte
induction therapy has been routinely used for pediatric cadaveric (CAD) and
living-related donor (LRD) renal allograft recipients at the University of
Tennessee, Memphis. Sixteen African-American first renal allograft recipients
received induction therapy: 11 CAD allografts (10 OKT3, 1 ATGAM) and five LRD
(all ATGAM). Sixteen Caucasian recipients received induction therapy; 3 CAD (all
OKT3), 1 living-unrelated donor (OKT3), and 12 LRD (9 ATGAM, 3 OKT3). Mean age at
renal transplantation was 11.8 and 10.5 years for African-American and Caucasian
recipients, respectively. Predicted graft survival (PGS) estimated by the Kaplan
Meier method for the African-American patients was 94% at both 1 and 3 years, and
for Caucasian patients was 94% and 85% at 1 and 3 years, respectively. Eleven
African-American CAD recipients had a PGS of 91% at 1 and 3 years. Renal
allograft survival for African-American and Caucasian pediatric recipients at our
center appears to be comparable. This could be due, in part, to the use of anti
lymphocyte induction therapy. However, other factors, such as improved compliance
or better immunological and pharmacological monitoring, may also have
contributed.
PMID- 9761351
TI - The ontogeny of the expression of K+ channel-like gene (CHIF) in the rat kidney
papilla.
AB - Recently, an IsK-like potassium (K+) channel corticosteroid-induced gene (CHIF)
was cloned. A high-K+ diet enhances, while a low-K+ diet decreases the expression
of this gene. The major expression of CHIF in the adult rat kidney is in the
papilla, where it is constitutive, in contrast to its inducibility by
corticosteroids and a low-salt diet in the rat colon. In order to further
understand the ontogeny of K+ clearance, we studied the presence of CHIF in the
kidney papilla in different stages of rat development. Total RNA from rat kidney
papillae of 1- to 3-day pre-labor unborn offspring, 2- to 3-day-old newborns, 10
day-old, 6-week-old, and 43-week-old rats underwent northern hybridization for
CHIF and the alpha-subunit of the Na+-K+-ATPase mRNA. Minor expression of CHIF
mRNA was found in fetal and newborn rat papillae, while older rats showed an age
related increase in gene expression. The expression of the alpha-sub unit of the
Na+-K+-ATPase was not age related. We conclude that CHIF is present in the rat
kidney papilla and the expression is related to age. The relative deficiency of
CHIF in the newborn may be one of the factors responsible for the reduced K+
clearance in is period.
PMID- 9761352
TI - Ovine AQP1: cDNA cloning, ontogeny, and control of renal gene expression.
AB - The cDNA for the ovine aquaporin 1 (AQP1) was obtained and found to be 97%, 88%,
and 85%, respectively, homologous to the bovine, human, and rat AQP1 cDNA. The
level of total kidney mRNA expressed as a ratio to glyceraldehyde-3-phosphate
dehydrogenase increased sevenfold from 60 days to 140 days of gestation (term=150
days) and reached adult values by 6 weeks after birth. Treatment of pregnant ewes
(and their fetuses) at 64 and 74 days of gestation with dexamethasone (0.76 mg/h
for 48 h) resulted in a small but statistically significant increase in AQP1 mRNA
only in the 74-day fetuses. By immunohistochemistry, it was shown that the
increase in AQP1 mRNA with dexamethasone resulted largely from an increase in
maturity of the inner zone of the fetal renal cortex (i.e., more tubules) as well
as stronger expression of AQP1 in proximal tubules and thin descending limbs of
loops of Henle. A similar effect occurred in fetuses infused for 3 days with
angiotensin I (6.7 microg/h) in the last third of gestation.
PMID- 9761353
TI - Expression of type IV collagen in the developing human kidney.
AB - The distribution of alpha1-6 chains of type IV collagen (alpha1-6(IV)) in human
fetal kidneys was examined by indirect immunofluorescence. By 11 weeks of
gestation, alpha1, 2, 3, 4, and 6(IV) were already present, but alpha5(IV)
appeared relatively late, at 21 weeks. Alpha1(IV) and alpha2(IV) were present in
all basement membranes, alpha3(IV) and alpha4(IV) were restricted to the
glomerular basement membrane and parts of the tubular basement membrane.
Alpha5(IV) was distributed in the glomerular basement membrane, Bowman's capsule,
and parts of the tubular basement membrane. Alpha6(IV) was present in the
Bowman's capsule, parts of the tubular basement membrane, and occurred in parts
of the glomerular basement membrane at the early capillary loop stage, but
disappeared during the later capillary loop stage.
PMID- 9761354
TI - Early sonographic aspects of kidney morphology in Bardet-Biedl syndrome.
AB - Bardet-Biedl syndrome is an autosomal recessive disorder characterized by
postaxial hexadactyly, obesity, mental retardation, pigmented retinopathy,
hypogonadism, and renal disease. Morphological changes are present in all areas
of the kidney, the renal medulla being the most frequently affected site. Cystic
and dysplastic changes are prevalent. Seven children from five families were
followed from birth through their 5th birthday. Serial renal sonography revealed
a number of characteristic features. Bilateral renal enlargement and increased
parenchymal echogenicity were present at birth. The usual corticomedullary
differentiation was absent. Pyramids were either not seen or deformed. With high
resolution ultrasonography, small cysts were detected at the corticomedullary
junction. After the 3rd month of life, there was a striking inversion of normal
echogenicity, the inner medulla became more echogenic and was demarcated from the
less-echogenic cortex. After 12 months, the kidney size regressed significantly.
Fetal lobulation persisted in some patients. In conclusion, ultrasonography is a
useful tool to evaluate the extent of renal lesions, but more importantly to
differentiate bilateral polycystic kidney diseases in the newborn period.
PMID- 9761355
TI - Benign methylmalonic acidemia in a sibship with distal renal tubular acidosis.
AB - Two male infants born to consanguineous parents were investigated for feeding
difficulties in the 1st month of life. Both were found to have distal renal
tubular acidosis (dRTA) with hypercalciuria. Nephrocalcinosis was present in the
first child but not in the second. Urinary organic acid profile demonstrated an
excess of methylmalonic acid (MMA) in both children in the absence of any other
organic acid. MMA mutase activity and propionate incorporation were normal. There
have been no neurological symptoms in either child. The first child has normal
growth and psychomotor development at 4 years. His brother, who also has
significant gastrooesophageal reflux, has failed to thrive and currently requires
nasogastric feeding and caloric supplements to maintain weight along the 3rd
percentile. Urinary and plasma MMA continue to be raised in both cases. The
association of increased urinary and plasma MMA and dRTA presenting in the 1st
month of life has not previously been reported and may represent a new syndrome
of autosomal recessive inheritance.
PMID- 9761356
TI - Kidney growth and renal function in unilateral multicystic dysplastic kidney
disease.
AB - The natural history of multicystic dysplastic kidney (MCDK) is not well
established. We analyzed kidney growth and renal function in 33 children with
prenatally diagnosed unilateral MCDK in a long-term study. The mean observation
period was 4.9 years with a range of 1-11.6 years. Abnormalities of the
contralateral kidney were found in 10 of 33 patients (30%): ureteropelvic
junction obstruction (5), ureterovesical junction obstruction (2), and
vesicoureteral reflux (3). In 6 children the dysplastic kidney had been removed.
Complete involution was observed in 48% and a decrease of size in 33% of 27
dysplastic kidneys. At the time of last examination, 27 of 29 children showed a
volume of the contralateral kidney above the normal range (>145%). Hypertrophy of
the contralateral kidney, defined as kidney length above 2 standard deviation
scores (SDS), was seen in 24% of 33 children at birth, thus showing that
hypertrophy of the contralateral kidney starts in utero and continues throughout
childhood. The extent of contralateral hypertrophy was independent of associated
abnormalities in this study. Mean creatinine was increased in the whole group
(mean +1.13 SDS). Calculated creatinine clearance in 21 patients over 2 years was
within normal limits, with a median of 102 ml/min per 1.73 m2 (range 84-143).
Based on the results of this and previous studies, nephrectomy cannot be
recommended in typical cases, but a regular follow-up of these patients seems
necessary.
PMID- 9761357
TI - Long-term nephrotoxicity of cisplatin, ifosfamide, and methotrexate in
osteosarcoma.
AB - The acute renal effects of chemotherapy are known, but long-term nephrotoxicity
has rarely been investigated. The aim of the present study was to assess long
term renal function in children and adolescents who received at-risk
chemotherapy, including cisplatin, ifosfamide, and methotrexate, to treat an
osteosarcoma. Renal function tests [creatinine clearance, microalbuminuria, and
renal excretion of sodium, potassium, chloride, calcium, magnesium (Mg),
phosphorus (P), and uric acid] were prospectively performed 5.4+/-2.2 (+/-SD)
years after chemotherapy (total cumulative dose: methotrexate 41+/-31 g/m2,
ifosfamide 39+/-14 g/m2, cisplatin 674+/-188 mg/m2) in 18 children and
adolescents. The results were compared with 13 normal volunteers matched for age
and sex. Creatinine clearance, which was greater than 80 ml/min per 1.73 m2 in
all patients, correlated with the total dose of ifosfamide (r=0.55, P<0.05) and
cisplatin (r=0.48, P<0.05). Microalbuminuria was noted in 4 patients.
Hypomagnesemia was present in 4 and hypercalciuria in 3 patients; renal excretion
of P, Mg, and uric acid was higher in patients than in controls. Glomerular
function was not significantly altered and only mild tubular dysfunction was
present. Since renal excretion of P and Mg were increased in patients compared
with normal volunteers and hypercalciuria was occasionally seen, divalent ion
disorders are the most-likely potential complications.
PMID- 9761358
TI - Acute interstitial nephritis presenting as presumed minimal change nephrotic
syndrome.
AB - Nephrotic syndrome (NS) secondary to drug-induced acute interstitial nephritis
(AIN) is well described in adult but is very rare in children. We report an
unusual case of AIN mimicking prototypical childhood minimal change NS. A 2-year
old girl on long-standing amoxicillin therapy for vesicoureteral reflux presented
with the acute onset of generalized edema, proteinuria, hypoalbuminemia,
hypercholesterolemia, and an inactive urinary sediment. She was placed on empiric
steroid therapy for presumed minimal change NS. When she did not respond to
steroids, a renal biopsy was performed and revealed AIN. Her NS resolved
completely with cessation of her amoxicillin therapy and concomitant tapering of
her steroids. This patient demonstrates that the association of AIN with NS
should be carefully considered in children on antimicrobials who develop NS, even
in the absence of the classic clinical features of AIN. In addition to the usual
work-up and care of a child with NS, in these patients consideration may also
need to be given to withdrawal of the potential precipitating agent.
PMID- 9761359
TI - Magnetic resonance imaging in acute pyelonephritis.
AB - The diagnosis of acute pyelonephritis in children remains a clinical challenge.
We assessed the feasibility of magnetic resonance imaging (MRI) detection of
pyelonephritis in four pediatric patients and compared the results with renal
cortical scintigraphy. MRI revealed areas of high signal intensity in the kidney
that coincided with photon-deficient regions in the radionuclide scans in two
children with acute pyelonephritis. These findings confirm work in experimental
animals and indicate that MRI can accurately detect acute pyelonephritis in
children.
PMID- 9761360
TI - Peritoneal loss of insulin-like growth factor-I and binding proteins in end-stage
renal disease.
AB - The kinetics of peritoneal transport of insulin-like growth factor (IGF) system
related proteins during dialysis is not well characterized. We studied temporal
changes in dialysate and serum concentrations of IGF-I and IGF-II as well as IGF
binding protein (BP)-1, -2, and -3 in ten children with end-stage renal disease
(ESRD) undergoing continuous cycling peritoneal dialysis (CCPD) during a 4-h
peritoneal equilibration test (PET). Dialysate concentrations of IGF-I, IGF-II,
and all three IGFBPs demonstrated a time-dependent increase during PET. Despite
their transport, the serum concentrations of these proteins did not change
significantly during the PET. Dialysate/serum ratios for IGF-I, IGF-II, and IGFBP
1, -2, and -3 were significantly increased at 2 h and increased further at 4 h,
at which time values averaged 1.3+/-0.2%, 3.1+/-0.5%, 6.2+/-1.0%, 2.4+/-0.2%, and
1.3+/-0.2% of serum levels, respectively. The transperitoneal clearance
(microl/min per 1.73 m2) of the three IGFBPs was inversely related to both their
molecular weight and plasma concentration. However, peritoneal clearance of IGF-I
and -II was similar to that of the larger and more-abundant IGFBP-3. Mass
transfer rates (microg/h per 1.73 m2) for the IGFs and their binding proteins
were directly proportional to their prevailing plasma concentration. Based on
estimates of mass transfer, only a small molar excess of IGFBPs was removed from
the circulation relative to the combined molar concentration of IGF-I and IGF-II.
Hence, it seems unlikely that any beneficial effect of CCPD on growth in children
with ESRD is mediated via a preferential loss of IGFBPs into the dialysate fluid.
PMID- 9761361
TI - Ammonia clearance by peritoneal dialysis and continuous arteriovenous
hemodiafiltration.
AB - We report the use of continuous arteriovenous hemodiafiltration (CAVHD) in a
neonate with severe hyperammonemia due to a urea cycle disorder. We compared the
ammonia clearance (C(NH3)) for peritoneal dialysis (PD) and CAVHD. C(NH3) for
CAVHD was 7.45 ml/min per m2 at a dialysate flow of 300 ml/h and was 10.55 ml/min
per m2 at a dialysate flow rate of 600 ml/h. The mean PD clearance was 2.15
ml/min per m2. Our data suggest that CAVHD is superior to PD for the removal of
plasma ammonia. We conclude that CAVHD should be considered a reasonable
alternative in the treatment of neonatal hyperammonemia in urea cycle disorders
when medical treatment fails.
PMID- 9761362
TI - Hemodialysis catheter placement and recirculation in treatment of hyperammonemia.
AB - A 2-year-old girl with carbamoyl phosphate synthetase deficiency underwent
emergency hemodialysis (HD) for treatment of acute life-threatening
hyperammonemia. HD was performed via catheters placed in each femoral vein
serving as vascular access. The tip of one of the catheters (aspirating line) was
in the left external iliac vein and the tip of the other catheter (the return
line) was in the inferior vena cava (IVC). High blood flow rates were used in
order to rapidly lower the blood ammonia (NH3) levels. However, unanticipated
marked recirculation in the IVC, between the dialysis aspirating and return
catheters, was encountered, preventing significant reduction in blood NH3. The
recognition of this problem, suggested solutions, and prevention are described.
PMID- 9761363
TI - Regulation of cell survival during renal development.
AB - Apoptosis occurs in an orchestrated fashion during kidney development. In
contrast, it is a relatively rare event in normal developed (adult) kidney.
However, a predictable pattern of apoptosis is observed in adult kidney in two
settings, during which parts of the developmental pattern are recapitulated.
These are regeneration following acute ischemic injury and the process of
cystogenesis in polycystic kidney disease. Apoptosis in kidney is regulated by
agents both intrinsic and extrinsic to the renal cell. The protooncogene b-cell
lymphoma/leukemia gene product-2 (bcl-2) is an important intrinsic factor. The
growth factor epidermal growth factor is an important extrinsic regulator. A
thorough understanding of the control of renal apoptosis during development and
recovery from ischemic injury and in cystogenesis may lead to new therapies to
prevent or ameliorate abnormalities of kidney formation, to enhance regeneration
following acute ischemic injury, and to slow the progression of renal failure in
polycystic kidney disease.
PMID- 9761364
TI - The clinical pharmacology of loop diuretics in the pediatric patient.
AB - The loop diuretics furosemide and bumetanide are frequently employed in the
pediatric population for the management of fluid overload in both acute and
chronic disease states. They act mainly by inhibiting sodium reabsorption in the
nephron at the thick ascending limb of Henle's loop. Important pharmacokinetic
differences between adults and infants include a reduced clearance and prolonged
half-life, that may cause accumulation of these agents to potentially toxic
levels if dosing intervals are not adjusted. Unfortunately, little is known about
the time required for maturation of loop diuretic elimination in older infants,
children, and adolescents. Similar to adults, limited pharmacodynamic evidence in
neonates suggests that a maximally efficient diuretic dose exists. Increasing the
diuretic dose beyond this maximum does not offer further benefit, but may
increase the risk of toxicity. Common problems encountered in the pediatric
patient as well as in adults are loop diuretic tolerance and resistance. Loop
diuretic dosing strategies aimed at overcoming these phenomena include
administration by continuous infusion, coadministration with albumin, and
coadministration with metolazone or thiazides. This article reviews the
pharmacology, pharmacokinetics, and pharmacodynamics of furosemide and bumetanide
in pediatric patients. A better understanding of the clinical pharmacology of the
loop diuretics should aid clinicians in the development of dosing regimens aimed
at producing adequate diuresis without promoting excessive diuretic tolerance.
PMID- 9761365
TI - Prothrombin fragment 1+2 during oral anticoagulation in congenital nephrotic
syndrome.
PMID- 9761366
TI - Transferrin saturation in pediatric hemodialysis.
PMID- 9761367
TI - Signal transduction in leucocytes via GPI-anchored proteins: an experimental
artefact or an aspect of immunoreceptor function?
AB - Membrane proteins anchored in the membrane via a glycolipid
glycosylphosphatidylinositol (GPI) as well as some glycolipids are able to
transduce signals and induce diverse functional responses in cells upon their
cross-linking via antibodies or natural ligands. In some cases this signaling
capacity seems to be due to associations of these molecules with specific
transmembrane proteins. GPI-anchored proteins are components of membrane
microdomains enriched in glycosphingolipids and cholesterol and devoid of most
transmembrane proteins. These membrane specializations are relatively resistant
to solubilization in solutions of some mild detergents at low temperatures. These
'GPI-microdomains' contain also cytoplasmic signaling molecules such as Src
family protein tyrosine kinases and trimeric G-proteins. Thus, at least some
signaling elicited upon cross-linking of GPI-anchored proteins and glycolipids
may be due to perturbation of the signaling molecules associated with these
microdomains. It is suggested that these specialized areas of the membrane rich
in signaling molecules interact with immunoreceptors (TCR, BCR, Fc receptors)
cross-linked upon their interactions with ligands and importantly contribute to
initiation of proximal phases of their signaling pathways.
PMID- 9761369
TI - A caspase inhibitor protects thymocytes from diverse signal-mediated apoptosis
but not from clonal deletion in fetal thymus organ culture.
AB - A family of caspases has been implicated as an effector in various forms of
apoptosis. The present study investigated whether this family of proteases is
involved in the induction of intrathymic clonal deletion in comparison with
apoptosis induced in the thymus by various signals. Potent apoptosis of
thymocytes was induced in fetal thymus organ cultures (FTOC) when FTOC were
treated with glucocorticoid, radiation, and anti-CD3 monoclonal antibody (mAb).
As a model of negative selection based on apoptotic clonal deletion, the
elimination of Vbeta8-expressing thymocytes was induced by inoculating
Staphylococcal enterotoxin B (SEB) into FTOC. Addition of a peptide-based caspase
inhibitor resulted in the protection of thymocytes from apoptosis induced by
glucocorticoid, radiation, and anti-CD3 mAb. In contrast, the same treatment
failed to prevent clonal deletion of Vbeta8high thymocytes. These results suggest
that different pathways of cell death operate in the thymus that may be
distinguished depending on the caspase/protease utilized in each pathway.
PMID- 9761368
TI - Establishment and characterization of pro-B cell lines from motheaten mutant
mouse defective in SHP-1 protein tyrosine phosphatase.
AB - Mice homozygous for the motheaten (Hcph(me)) mutation lack a functional SHP-1
protein tyrosine phosphatase, show severe immunologic dysregulation and die at an
early age. Severe pneumonitis in me/me mice is associated with abnormal
proliferation of macrophages and granulocytes. Overgrowth of macrophages in long
term cultures of me/me bone marrow has prevented analyses of lymphopoiesis in
vitro. To establish hematopoietic cell lines from me/me mice, we cultured me/me
bone marrow with the PA6 stromal cell line in the presence of antagonistic
antibody against the receptor (c-Fms) for macrophage colony stimulating factor (M
CSF). In these cultures, overgrowth of M-CSF-dependent macrophages was suppressed
by the antagonistic antibody and other hemopoietic cell lineages were generated
efficiently from me/me bone marrow. By using this culture system, we established
me/me pro-B cell clones (MEBs) with rearranged DH-JH but not VH-DJH. The growth
of MEB clones required IL-7 and c-Kit ligand, corresponding to normal pro-B cells
which express SHP-1. MEB cells were sensitive to starvation by either IL-7 or c
Kit ligand, resulting in apoptotic death. The present culture system, which
supports hematopoiesis of me/me bone marrow, provides useful tools for the
determination of the role of SHP-1 in signal transduction of B lymphopoiesis.
PMID- 9761370
TI - Donor-specific stimulation of peripheral blood mononuclear cells from recipients
of orthotopic liver transplants is associated, in the absence of rejection, with
type-2 cytokine production.
AB - In this study, we examined the cytokine production by human peripheral blood
mononuclear cells (PBM) from recipients of orthotopic liver transplants which had
been stimulated by donor-specific alloantigen. Levels of interleukin (IL)-2, IL
4, interferon (IFN)-gamma, IL-10 and transforming growth factor (TGF)-beta
produced in vitro from PBM of 15 transplant recipients at 5-7 months post
transplantation were analysed after donor-specific, third-party, or non-specific
stimulation. Mononuclear cell proliferation in response to stimulation and
cytokine mRNA from the cell cultures were assayed. Donor-specific antigen was
obtained from donor spleen cells which had been obtained and frozen in liquid
nitrogen at the time of organ retrieval. Third-party restimulation used
equivalent numbers of spleen cells pooled from the other 14 organ donors.
Cytokine production was correlated with the clinical condition of the patient,
including biopsy results when available, and biochemical data. The data show a
highly significant correlation between the donor-specific- and third-party-
stimulated IL-4 and IL-10 production from recipient PBM with stable liver graft
function as assessed by histopathology and/or biochemistry. This correlation was
independent of level of immunosuppression. These data strongly support a role for
IL-4 and/or IL-10 in the induction and/or maintenance of tolerance to human liver
allografts. Measurement of the levels of these cytokines from recipient PBM after
donor-specific antigen stimulation in vitro may be a useful test for monitoring
for acute allograft rejection.
PMID- 9761372
TI - Different effect of 1,25-dihydroxyvitamin D3 on replication of Mycobacterium
avium in monocyte-derived macrophages from human immunodeficiency virus-infected
subjects and healthy controls.
AB - Mycobacterium avium complex (MAC) is the most common cause of disseminated
bacterial infection in patients with acquired immune deficiency syndrome (AIDS)
and macrophage dysfunction is important both in the pathogenesis of AIDS- and MAC
infection. 1,25-Dihydroxyvitamin D3 (1,25D), the active metabolite of vitamin D,
has a number of effects on cell types of the immune system including
monocytes/macrophages. The present study was designed to investigate whether
1,25D supplementation in vitro could modulate MAC replication in macrophages from
HIV-infected patients. It was therefore of particular interest to examine whether
the effect of 1,25D differs between cells from HIV-infected patients and healthy
control subjects. After 3 and 7 days of infection, 1,25D supplementation
increased numbers of bacteria in cells from control subjects. In contrast, there
was no change or even a decrease in numbers of bacteria in cells from HIV
infected patients. These findings suggest that HIV infection may significantly
modulate the macrophage response to 1,25D stimulation, and that 1,25D may have
inhibitory effects on MAC replication in macrophages from HIV-infected patients.
PMID- 9761371
TI - Activation of CD4+ and CD8+ parasite -specific T-cells by macrophages infected
with live T. cruzi amastigotes.
AB - T. cruzi-infected macrophages are potential candidates for the presentation of
parasite antigens to T. cruzi-specific T lymphocytes. To assess this question, we
examine the ability of peritoneal exudate macrophages to process exogenous live
or dead parasites and to activate defined populations of T. cruzi-specific immune
T-cells. Macrophages infected with live amastigotes activated both lymph node
CD4+ and spleen CD8 + T-primed cells that proliferated and secreted cytokines.
Lymph node CD4+ T-cells produced IFN-gamma and IL-10 while CD8 + T-cells produced
IFN-gamma. In contrast, macrophages pulsed with dead parasites activated only
lymph node CD4+ T-cells, which proliferated and secreted IFN-gamma.
Interestingly, the immunization with heat-killed parasites primed mice for CD8+ T
cells which were expanded in vitro by recognition of infected macrophages. Taken
together, these results demonstrated that amastigote infected macrophages present
parasite peptides associated with MHC I and II molecules, activating both CD4 +
and CD8+ T-cells. Furthermore, the development of T. cruzi-specific CD8+ T-cells
in vivo using the immunization protocol with non-living parasites as described in
this report could be explored for further studies on the role of CTL in the
outcome of infection.
PMID- 9761373
TI - Nitric oxide-induced apoptotic cell death in the acute phase of Trypanosoma cruzi
infection in mice.
AB - Production of gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF
alpha) in Trypanosoma cruzi-infected mice results in the activation of inducible
nitric oxide synthase (iNOS) and in elevated nitric oxide (NO) synthesis, which
is important for the macrophage trypanocidal activity. However, NO has been shown
to be involved in suppression of host immunity. In the present investigation, we
studied the role of NO in inducing apoptosis in cells from BALB/c mice acutely
infected by T. cruzi. Splenocytes from infected mice had a reduced cell viability
and elevated levels of spontaneous apoptosis after 48 h in culture. Inhibition of
NO production by the addition of the L-arginine analog NG-monomethyl-L-arginine
(L-NMMA), or of monoclonal antibodies (mAbs) to IFN-gamma or TNF-alpha spleen
cells, partially restored cell viability and caused a decrease in the levels of
apoptosis in splenocytes from infected animals. Spleen cells from T. cruzi
infected mice had an apoptosis-specific pattern of internucleosomal DNA
fragmentation which was most marked at the ninth day after infection when the
plasma NO levels and parasitemia were increased. Treatment of infected mice with
L-NMMA, anti-TNF-alpha, or anti-IFN-gamma mAbs caused reduction of both NO
production and the amount of apoptotic cells, suggesting that NO plays a direct
role in the induction of apoptosis in vivo. Taken together, these data support
the hypothesis that, as well as modulating immunosuppression, NO produced by IFN
gamma and TNF-alpha activated macrophages plays a role in apoptosis induction
during the acute phase of experimental T. cruzi infection.
PMID- 9761374
TI - Natural killer cell mediated cytotoxicity against VERO target cells; the
suppressive effect of pentoxifylline.
AB - The K-562 cell line is widely known and used as a NK cell target. In this study
we report that VERO (African green monkey kidney epithelial cell line) is an
excellent target of the human NK cell cytotoxicity. Considerable cytotoxicity was
observed in a 4 h 51Cr release assay with nonadherent and immunomagnetically
separated CD56+ NK cells from PBMC. On the contrary, adding K-562 cells as cold
target to the assay the cytotoxicity significantly decreased. Using a standard
chromium-release assay the NK cell activity (NKCA) against VERO cells was
investigated in a population of healthy volunteers (mean value of cytotoxicity
was 26.6%) and compared with the values of cytotoxicity against K-562 target
cells (32.6%). The difference was not significant (P > 0.05). The suppressive
effect of PTX on in vitro NK cell activity was observed at concentration of 100
microg/ml using VERO target cells as well as K-562 cells. Our studies provide the
first evidence that the NK cell activity is suppressed in vitro by PTX using VERO
cells as NK target cells.
PMID- 9761375
TI - Long term safety and efficacy of intraperitoneal insulin infusion by means of
implantable pumps.
PMID- 9761376
TI - Testosterone and progesterone level alterations in the adult rat after retinoid
(retinol or retinoic acid) treatment (imprinting) in neonatal or adolescent age.
AB - Newborn rats were treated with a single dose of vitamin A (retinol), or with
three doses of retinoic acid (in the 1st, 3rd and 5th days). Serum testosterone
and progesterone level was measured in the four months old male and female rats,
respectively. Retinol significantly decreased both hormone levels, however
retinoic acid decreased the progesterone level only. In the second part of the
experiments adolescent rats (in the 6th and 7th week after birth) were treated
and measured similar to the newborns. In this case retinol significantly
diminished testosterone level, without influencing the progesterone level.
Retinoic acid decreased testosterone level and elevated progesterone level. The
results demonstrate the long lasting effects of retinoid treatments at a neonatal
or adolescent age, pointing also to the differences in the direction of the
effects. Considering that previously the receptorial and sexual-behavioral
effects of perinatal vitamin A treatments were observed, the experiments call
attention to such harmful influences of perinatal vitamin A treatments, which are
not manifested in morphological alterations.
PMID- 9761377
TI - Gene expression and roles of angiotensin II type 1 and type 2 receptors in human
adrenals.
AB - Although stimulation of aldosterone secretion is one of the functions of
angiotensin II, the gene expression and biological significance of the
angiotensin II receptor subtypes, AT1 and AT2, in the human adrenal have not been
characterized. We therefore investigated the transcription levels of the receptor
subtype genes and their roles in regulation of steroid secretion by human
adrenals. The expression of AT1 and AT2 receptor mRNA was assessed by reverse
transcription-polymerase chain reaction followed by Southern blot analysis in
normal adrenocortical tissues (n = 6) and a series of adrenal tumour tissues:
aldosterone-producing adrenocortical adenoma (n=6), Cushing's syndrome (n = 6)
and pheochromocytoma (n = 6). The role of the two receptor subtypes in steroid
secretion in vitro was examined by incubating the tissue with angiotensin II(1
microM) with or without the selective AT1 antagonist CV-11974 (1 microM). Both
AT1 and AT2 receptor mRNA transcripts were demonstrated in all of the human
adrenal tissues tested. Angiotensin II-induced aldosterone secretion was
suppressed 50% upon the addition of CV-11974. The selective AT2 agonist CGP-42112
increased aldosterone secretion by 55% over the control, which was not suppressed
by CV-11974. Angiotensin II and CGP-42112 did not affect cortisol secretion.
These results suggest that both AT2 and AT1 receptors may be involved in the
regulation of aldosterone secretion and tumorigenesis of the human adrenals.
PMID- 9761378
TI - Inhibitory effect of pentoxifylline on HLA-DR expression and glycosaminoglycan
synthesis by retrobulbar fibroblasts.
AB - OBJECTIVE: Glycosaminoglycan (GAG) production by retro-ocular fibroblasts (REF)
is increased in patients with thyroid-associated ophthalmopathy (TAO). Various
cytokines stimulate REFs to proliferate and elaborate GAG, free oxygen radicals
as well as induce HLA-DR expression on these cells. Pentoxifyllin (Ptx) regulates
the production of several cytokines including tumor necrosis factor alpha (TNF
alpha), interleukin-1 (IL-1) and, interferon gamma (IFN-gamma). We wished in this
study to determine whether Ptx modified the spontaneous and cytokine-induced GAG
synthesis by REF and IFN-gamma induced HLA-DR expression. DESIGN: REF derived
from extraocular muscles of healthy subjects were cultured without and with
cytokines (IFN-gamma, TNF alpha and IL-1) and the effect of Ptx on the production
of GAG by REF and HLA-DR expression was determined. MEASUREMENTS:
Glycosaminoglycan was measured by incorporation of (3H) glycosamine into GAG. HLA
DR expression was analyzed by fluorescence activated cell sorter. RESULTS: Both
spontaneous and cytokine induced GAG synthesis by REF was inhibited by Ptx (100,
500 and 1000 mg/l, respectively). IFN-gamma (50, 100 and 500 U/ml) induced a dose
dependent increase in the expression of HLA-DR molecules by REF. Ptx, which was
not toxic to REF, inhibited HLA-DR expression on those cells dose-dependently.
CONCLUSIONS: Our in vitro results suggest that Ptx reduces cytokine-induced GAG
production and HLA-DR expression by REF. It thus has potential as a therapeutic
agent which regulates the function of lymphocytes infiltrating the retro-orbital
tissues, and which are instrumental in TAO.
PMID- 9761379
TI - Influence of orchidectomy and ovariectomy on the blood-brain barrier permeability
during bicuculline-induced seizures.
AB - The changes in the permeability of the blood-brain barrier (BBB) during
bicuculline-induced seizures were investigated in ovariectomized female and
orchidectomized male rats. The rats were anesthetized with diethyl ether. Evans
blue, which was used as a BBB tracer, was injected into femoral vein 5 min before
administering bicuculline to induce grandmal seizures. Ten groups of rats were
studied: Group I: control female; Group II: control male; Group IIl: intact
female + bicuculline; Group IV: intact male + bicuculline; Group V:
ovariectomized female; Group VI: orchidectomized male; Group VII: ovariectomized
female + bicuculline; Group VIII: orchidectomized male + bicuculline (1.2 mg/kg,
i.v.); Group IX: ovariectomized female + estrogen + bicuculline; Group X:
orchidectomized male + estrogen + bicuculline. Adult male and female rats were
orchidectomized and ovariectomized 3 weeks before the experiments, or sham
operated under general anesthesia. During bicucculline-induced seizures, the mean
arterial blood pressure increased significantly in both intact and ovariectomized
and orchidectomized rats. BBB lesions were present in 80 percent of intact female
rats and 50 percent of ovariectomized rats after bicuculline-induced seizures.
This difference between intact and ovariectomized rats was found to be
significant (p < 0.01). There was no statistically significant change in the BBB
permeability between intact and orchidectomized rats after convulsion. Generating
seizures in both ovariectomized and orchidectomised rats, after administrating of
estrogen, did not lead to any significant alteration in BBB permeability. Our
results suggest that the extravasation of Evans blue albumin was most pronounced
in the brain of intact female rats when compared to ovariectomized rats after
bicuculline-induced seizures. After administrating estrogen, the decreased BBB
permeability values of ovariectomised rats could not reach the values in intact
rats.
PMID- 9761380
TI - Comparison of the effects of simmondsin and cholecystokinin on metabolism, brown
adipose tissue and the pancreas in food-restricted rats.
AB - In this study, we investigated the analogies between the physiological effects of
simmondsin, a satiety-inducing glycoside extracted from jojoba seeds, and the
gastro-intestinal satiation peptide, cholecystokinin. The effects of
intraperitoneal injection of the biological active CCK-octapeptide on the
pancreas, interscapular brown adipose tissue, growth performance and energy
metabolism in normal-fed, severely food intake-restricted (50 % of normal food
intake) or moderately food intake-restricted (65 % of normal food intake) growing
rats were compared to the effects of 0.25 % simmondsin mixed in the food,
inducing moderate food intake reduction (65 % of normal) in rats. Cholecystokinin
induced pancreatic hypertrophy. In normal fed rats, cholecystokinin had no effect
on brown adipose tissue or growth, while, in severely food intake-restricted
rats, it caused brown adipose tissue hypertrophy and reduced growth. In
moderately food intake-restricted rats, both cholecystokinin and simmondsin
induced pancreatic hypertrophy, increased brown adipose weight and metabolism and
caused a slight decrease in growth. We conclude that cholecystokinin may decrease
growth performance in fast growing severely food intake-restricted rats by
stimulating brown adipose tissue metabolism, probably because of protein shortage
induced by pancreatic hyperstimulation. Simmondsin has similar effects. These
results support the hypothesis that endogenous cholecystokinin is involved in the
effects of simmondsin in rats.
PMID- 9761381
TI - Xenotransplantation of adult porcine islets in diabetic mice. A study of UVB
irradiation, cryopreservation and immunosuppression on graft survival time.
AB - The major obstacle for successful xenotransplantation of islets to large animals
and human diabetics is the host rejection. To address the rejection problem, we
studied the efficacy of UV-B irradiation, cryopreservation and immunosuppression
on the in vivo functional time and immunogenicity of adult porcine islets (PI) in
outbred CD1 mice. Exposure of PI to UV-B irradiation between 300-1800J/M2 did not
affect the cellular viability as assessed by fluorescein diacetate or their daily
insulin secretion in vitro. Fresh PI normalized the blood glucose (BG) of
diabetic CD1 mice for 3.1+/-0.6 (n = 8, mean+/-SEM) days. Islets treated with
600J/M2 UV-B irradiation or cryopreservation had similar graft functional times
to fresh islets upon transplantation in diabetic CD1 mice. Immunosuppression with
cyclosporin A (CsA), antilymphocyte serum (ALS) and FK506 prolonged the
functional time of fresh pig islets to 7.9+/-0.9 (n = 9), 6.2+/-1.3 (n = 5) and
24.2+/-10.4 (n = 12) days, respectively. However, additional pretransplant
treatment with either UV-B irradiation or cryopreservation did not further
increase the functional time of pig islets in mice immunosuppressed with CsA.
Furthermore, there was no apparent difference in the frequency of appearance of
cytotoxic antibodies and antibody titers in the recipients of UV-B irradiated or
cryopreserved pig islet compared with non-treated islets. The UV-B irradiation
and cryopreservation of PI before transplantation with the present protocols did
not appear to have significant effect on the islet immunogenicity when assessed
by in vivo survival duration and anti-donor antibody titer production.
PMID- 9761382
TI - Nephrectomy decreases amylin and pramlintide clearance in rats.
AB - Amylin is a 37 amino acid hormone, co-secreted with insulin from the pancreatic
beta-cell in response to nutrient stimuli. Because the human amylin analog,
pramlintide, is being tested in patients with diabetes mellitus, a known risk
factor for nephropathy, we examined the role of the kidney on amylin and
pramlintide metabolism and action in functionally nephrectomized rats.
Nephrectomy markedly altered amylin metabolism: it increased incremental area
under the plasma amylin concentration curve 3.6-fold (P<0.001) and increased the
elimination half-life from 17+/-1 to 26+/-2 minutes (P < 0.01) after subcutaneous
injection of 100 microg amylin. Nephrectomy decreased plasma amylin clearance
from 20.3+/-1.1 to 7.9+/-0.4 mL/min (P < 0.0001). Thus, at these doses in the
rat, the kidney is important for metabolizing amylin and pramlintide.
PMID- 9761383
TI - Effects of rat amylin on renal function in the rat.
AB - Amylin is a peptide secreted from the pancreatic beta-cell along with insulin in
response to nutrient stimuli. Amylin has been reported to delay gastric emptying,
inhibit glucagon secretion and gastric acid secretion, increase plasma lactate,
plasma glucose and plasma renin activity, and decrease plasma calcium. Receptors
for amylin have been found in the rat nucleus accumbens and the kidney. In the
present experiments, amylin was administered to anesthetized rats by continuous
intravenous infusions at varied rates. Amylin significantly increased urine flow
at an infusion rate resulting in a plasma concentration of approximately 52 pM,
and at a concentration of approximately 193 pM, it increased sodium excretion,
glomerular filtration rate and renal plasma flow. Renal calcium and potassium
excretion were significantly elevated at plasma amylin concentrations of
approximately 52 pM and 193 pM, respectively. Higher concentrations of plasma
amylin decreased plasma calcium and potassium and blunted urinary excretion of
these electrolytes. Thus, of the renal responses tested, diuresis and natriuresis
appeared to be the most sensitive to infused amylin. These renal effects occurred
only at plasma concentrations above the normal range, but within the range of
concentrations reported in insulin resistant rats.
PMID- 9761384
TI - Peripheral plasma levels of beta-endorphin in alcoholics and highly trained
athletes and the relationship to a measure of central opioid tone.
AB - Human beta-endorphin-like immunoactivity was measured in highly trained athletes
(n = 10), alcoholics in the early phase of abstinence (n=9) and normal controls
(n=15) using the Nichols Allegro immunoradiometric assay. The assay was examined
for cross reactivity against related peptides, beta-lipotropin and human N-acetyl
beta-endorphin. Venous blood sampling was carried out in the morning at 0900 and
1100 hours in a fasting state. Using two-way analysis of variance there was a
significant effect of subject group on beta-endorphin concentration (p=0.029).
Post-hoc analysis using the Bonferroni t-test showed that the source of the
difference was the alcoholic group having significantly lower beta-endorphin
immunoreactivity (p < 0.05). There was no difference between the controls and the
athletes. There was a positive correlation between plasma beta-endorphin level at
1100 hours and the subsequent ACTH incremental response to naloxone in the group
as a whole (r=0.48, p=0.004). The assay showed 100% cross reactivity with beta
lipotropin and 73% cross reactivity with N-acetyl-beta-endorphin. We conclude
that alcoholics have reduced levels of beta-endorphin-like immunoactivity. While
beta-endorphin is known not to cross the blood-brain barrier, levels of plasma
beta-endorphin-like immunoactivity may indirectly reflect central opioid
activity.
PMID- 9761385
TI - Decreased in vitro IL-4 [corrected] and IL-10 production by peripheral blood in
first degree relatives at high risk of diabetes type-I.
AB - There is mounting evidence that the imbalance between Th1 and Th2 lymphocyte
subsets plays a key role in the development of autoimmune diabetes in NOD mice,
but it is also possible in humans. The aim of the present study was the
estimation of in vitro production of Th1 (INF-gamma, IL-2) and Th2-derived (IL-4,
IL-10) cytokines by peripheral blood in ICA and GADA positive first degree
relatives of Type-I diabetes patients, since they could represent primary events
triggering an immune-mediated islets destruction. The study was performed in 25
subjects at risk of insulin-dependent diabetes and 21 age- and sex-matched
healthy controls. Cytokine levels in supernatants of whole blood cultures with
PHA (10 microg/ml) were quantified by ELISA. We observed a lower concentration of
IL-4 in culture supernatants in ICA and GADA positive relatives as compared with
the control group, both at 48 h and at 72 h of incubation. Similarly, in the
prediabetic group, lower IL-10 levels at 48 and 72 h of culture were found. We
did not observe statistical differences in in vitro production of IL-2 and INF
gamma by peripheral blood in high risk diabetes mellitus subjects and healthy
controls. In subjects at increased risk of Type-I diabetes, levels of IL-4
positively correlated with those of IL-10. There were negative correlations
between IL-10 concentration after 48 h of incubation and levels of HbA1C. In
conclusion our study has shown decreased IL-4 and IL-10 production, but normal
secretion of Th1-derived cytokines by peripheral blood of prediabetic humans.
This could suggest that the early stage of autoimmune process in Type-I diabetes
in humans is associated with decreased function of Th2-cells rather than
overactivation of Th1 subset in the peripheral blood.
PMID- 9761386
TI - Power spectral analysis of variations in heart rate in patients with
hyperthyroidism or hypothyroidism.
AB - Power spectral analysis (PSA) of the variation in heart rate is useful in
determining the relative activity of the sympathetic and parasympathetic nerves.
In this study, PSA was used to investigate the relationship between abnormalities
in autonomic nerve function and the presence of thyroid disorders in patients
with autoimmune thyroid diseases. The low frequency (LF) or high frequency (HF)
components of R-R variations were determined by PSA. The coefficient of variation
of the R-R time intervals (CV(R-R)) was positively correlated with HF in healthy
subjects. In untreated hyperthyroid patients with Graves' disease, the CV(R-R)
and HF values were significantly lower than in healthy controls. Moreover, the
LF/HF ratio in patients with untreated Graves' disease was significantly higher,
and the LF/HF ratio in hypothyroid patients with Hashimoto's thyroiditis was
significantly lower than in healthy controls. A negative correlation was observed
between serum levels of free thyroid hormones (FT4 and FT3) and HF in Graves'
disease patients. In some hyperthyroid patients, antithyroid drug therapy or beta
blocker administration gradually restored reduced HF values. Present results
suggest that relative vagal nerve activity is reduced in hyperthyroid patients
and that this reduction is reversible according to the decrease in serum levels
of thyroid hormones.
PMID- 9761387
TI - Ultrasound transmission speed and ultrasound bone profile score (UBPS) of the
phalanges in normal women and women with osteoporosis.
AB - The distal metaphysis of the first phalanx of the fingers II-V is, like the
vertebral body, a useful site for the measurement of mineralisation and structure
of the bone because of the simultaneous presence of compact and trabecular bone.
With an ultrasound device (DBM sonic 1200, IGEA, Italy), we measured the adSOS
(the amplitude dependent speed of sound) and the UBPS (ultrasound bone profile
score), a score which is calculated from the graphic traces of the receiving
probe with an expert system which uses fuzzy-logic at phalanges II-IV, as well as
bone mineral density (BMD) at lumbar spine using dual X-ray absorptiometry (DXA).
Precision of the measurements was as follows: adSOS: short-time-CV% = 0.576, long
time-CV% = 1.1, SCV% = 5.9, RMSSD% = 1.825. UBPS: short-time CV% = 5.95. There
was no correlation between adSOS or UBPS and lumbar BMD (DXA). There was a
significant positive correlation between adSOS and UBPS, r = 0.804 (p<0.00001).
The validity of adSOS and UBPS was examined in 25 young and healthy women (mean
age: 33.4 year), 15 postmenopausal healthy women (mean age: 58.5 years), 17 women
with osteopenia, (mean age: 52.4 years), as defined by a t-score between -1 to
2.5 SD as lumbar BMD (DXA), and 20 women with osteoporosis and vertebral
fractures (mean age: 61.4 years). We compared the healthy postmenopausal women
and the women with osteoporotic vertebral fractures, the z-score of the adSOS was
below minus 1.5 SD and UBPS was below 40, sensitivity was 0.7 for adSOS, and 0.85
for UBPS, with a specificity 0.97 for adSOS, and of 0.93 for UBPS; positive
predictive value: adSOS: 0.93, UBPS: 0.85. AdSOS declined with age (r= 0.694,
p=0.021); the UBPS was not age dependent (r=-0.15, p = n.s.). The ROC-curve shows
a value of 0.96 for adSOS and 0.94 for UBPS. AdSOS and UBPS could discriminate
well between the healthy controls and the women with osteopenia or vertebral
fractures (p<0.00001). These results show that adSOS and UBPS are precise
parameters to be measured at the phalanges. The detection level of pathological
changes in osteoporosis are similar between adSOS and lumbar BMD (DXA) and
improved by using the UBPS. This might be explained by the influence of
structural changes in bone on UBPS, rather than change in bone mineral alone.
Prospective studies have to clarify the role of adSOS and UBPS in fracture
prediction.
PMID- 9761388
TI - The yeast genome and clinical genetics.
PMID- 9761389
TI - Genetic landmarks through philately--Gregor Johann Mendel (1822-1884).
PMID- 9761390
TI - Life expectancy in British Marfan syndrome populations.
AB - A total of 206 patients with Marfan syndrome were ascertained throughout genetic
clinics in Wales and Scotland during the period 1970-1990. There were 45 deaths
representing 22% of the cohort. Mean age at death was 45.3+/-16.5 years. 50%
median cumulative survival in the total cohort (n=206) was 53 years for males and
72 years for females. Multivariate analysis confirmed severity as the best
independent indicator of survival. These findings and survival curves will assist
in the counselling of British families and individuals with Marfan syndrome.
PMID- 9761391
TI - A gene-dosage PCR method for the detection of elastin gene deletions in patients
with Williams syndrome.
AB - Williams syndrome (WS) is a multisystem developmental disorder associated with
microdeletions at 7q11.23 that involve several genes, including the elastin gene.
Using genomic DNA from a panel of normal individuals and WS patients with
established hemizygosity of the elastin gene locus, we have developed a
quantitative polymerase chain reaction (PCR)-based gene-dosage assay that rapidly
detects the loss of one allele of the elastin gene. Using this procedure, we also
studied a family in which the proband was previously diagnosed with WS and her
mother with a balanced 7q translocation [t(7:11)(q34;q13)]. Using DNA isolated
from buccal smears obtained from several individuals in this family we were able
to establish normal disomy at 7q in all family members except for the proband, in
which we established hemizygosity at the elastin gene locus. We were also able to
successfully infer normal disomy in an unborn child in this family. The rapid
diagnostic procedure described here may have a variety of applications, including
fine mapping of deletion breakpoints at 7q11.23 associated with WS.
PMID- 9761392
TI - Neuropathological findings in Moebius syndrome.
AB - Pathological findings in two patients with Moebius syndrome and lethal fetal
akinesia sequence are described. In both patients a congenital brain stem
malformation with neuronal loss in the cranial nerve nuclei and tegmental
microcalcifications was observed. In one patient, the association with
splenogonadal fusion was observed, whilst in the second patient, the association
with tetraperomelia was present. As the association of peromelia and
splenogonadal fusion is a well-known association, the different combination of
splenogonadal fusion, peromelia and Moebius syndrome due to congenital brain stem
anomalies with necrosis might be the result of a disruptive phenomenon during a
prolonged vulnerable critical period in the 5th and 6th week of embryonic life.
The finding of olivary dysplasia in one case, reminiscent of olivary dysplasia in
Zellweger syndrome and in Miller Dieker syndrome, might suggest a primary
malformation underlying Moebius syndrome due to brain stem defects.
PMID- 9761393
TI - Molecular analysis of the BRCA2 gene in 16 breast/ovarian cancer Spanish
families.
AB - The recent isolated gene BRCA2 is responsible for about 45% of familial breast
cancer and the majority of male breast cancer families. In order to evaluate the
role of inherited BRCA2 mutations in Spanish families, the complete coding
sequence of the gene was screened by SSCP/sequencing in 16 high-risk
breast/ovarian cancer families. Four mutations were found that cause a premature
termination codon. Two of them have been reported elsewhere and one is a novel
mutation. In addition we have found seven polymorphisms, two of which have not
been previously described. One of the mutations, 936delAAAC was found in two of
our high-risk families. Because this mutation is considered as recurrent, we have
tried to estimate its frequency in our breast cancer population. A total of 127
moderate- high-risk families were screened for this mutation and it was also
found in another high-risk family. All the families carrying the 936delAAAC
mutation harboured part of a common haplotype shared by other reported carriers,
suggesting a possible founder effect for this mutation.
PMID- 9761394
TI - Spinal and bulbar muscular atrophy (SBMA): somatic stability of an expanded CAG
repeat in fetal tissues.
AB - Spinal and bulbar muscular atrophy (SBMA) is a rare X-linked motor neuron
degenerative disease caused by an expanded trinucleotide repeat. Unlike most
other trinucleotide repeat diseases, SBMA shows limited meiotic instability, and
evidence thus far indicates absence of somatic instability in adults. Data
regarding the presence of fetal tissue somatic mosaicism is unavailable. We
present a family in which a woman whose father had SBMA requested prenatal
testing. After informed consent. molecular genetic evaluation showed the male
fetus to carry the SBMA repeat elongation. Testing of fetal tissues after
elective pregnancy termination showed no somatic mosaicism in the CAG repeat
length. This is the first report of molecular genetic analysis of multiple
tissues in an affected fetus, and only the second report of prenatal diagnosis in
SBMA.
PMID- 9761395
TI - Polymorphic variants within the homeobox gene MSX1: a candidate gene for
developmental disorders.
PMID- 9761396
TI - Map refinement of the Usher syndrome type 1B gene, MYO7A, relative to 11q13.5
microsatellite markers.
AB - Usher syndrome (US) is clinically and genetically a heterogeneous group of
disorders characterized by the association of deafness with retinitis pigmentosa.
So far, eight genes responsible for US have been mapped, of which only the gene
responsible for the most common form, USH1B, has been identified. The USH1B is a
large gene containing 49 exons and encoding for an unconventional myosin-VIIA
(MYO7A). Mutation analysis within the MYO7A gene showed a wide variety of
mutations dispersed all over the gene. The present report refines the location of
the MYO7A gene relative to microsatellite markers mapped to this region, thereby
allowing a reliable and efficient carrier detection by linkage analysis.
PMID- 9761397
TI - Involvement of 9q22.1-31.3 region in pyloric stenosis.
PMID- 9761398
TI - The common features of patients with partial trisomy of the long arm of
chromosome 1.
PMID- 9761399
TI - Monozygotic monoamniotic twins discordant for urethral and anal atresia with
vesicorectal fistula: a favourable combination of defects.
PMID- 9761400
TI - Prevalence of high affinity IgE receptor [Fc epsilon RI beta] gene polymorphisms
in Kuwaiti Arabs with asthma.
PMID- 9761401
TI - Debriefing after psychological trauma.
PMID- 9761402
TI - The treatment of social phobia: a critical assessment.
AB - This article critically reviews the effects of psychological treatment (exposure,
cognitive restructuring, social skills training) and pharmacological treatment
(MAOIs, reversible MAOIs, anxiolytics and SSRIs) of social phobia. Only
controlled studies have been included, and their outcomes were assessed for
improvement in anxiety and avoidance, social functioning and clinical status.
Both psychological and pharmacological treatments resulted in a significant and
meaningful reduction in anxiety and, in most cases, a weakening of the tendency
to avoid. Although useful, the effects were not of such a magnitude as to result
in remission. Reduction in anxiety was long-lasting in patients treated by
psychological methods. The lessening of anxiety did not necessarily lead to
meaningfully improved social functioning. The combination of psychological and
pharmacological treatments was disappointing, and did not exceed the effects of
psychological treatments alone. However, the most promising medications were not
tested. Subtype of social phobia and additional diagnoses did not determine the
response to treatment.
PMID- 9761403
TI - Mental health expectancy: an indicator to bridge the gap between clinical and
public health perspectives of population mental health.
AB - Mental health indicators generally used in public health are derived from
mortality statistics, but they do not reflect the impact that disability due to
mental disorders has on population health. The present study proposes a global
indicator of population mental health which combines both mortality and morbidity
data. The data used were the results of a Health Interview Survey, including the
12-item version of the General Health Questionnaire, mortality life-tables for
the general population, and data from a two-step epidemiological study used to
assign the probability of case status. The results are calculated for the
Catalonia region in north-east Spain. Life expectancy and mental health
expectancies at all ages were found to be higher for women than for men. Men were
found to have a higher total life expectancy in good mental health. The
feasibility and potential areas of application of this generic mental health
index are discussed.
PMID- 9761404
TI - Depressive disorders among somatizing patients in primary health care.
AB - Unrecognized, untreated and undertreated depressive disorders incur inordinate
human and economic costs, despite the availability of an exclusive array of
clinical interventions. The aim of this study was to identify cases of masked
depression in primary health care, employing a two-stage design. In the first
stage, involving a study of 442 patients, the prevalence of recognized depression
was 1.8%. In the second step, 62 patients from stage 1 were investigated further
because of their high score on somatization tendency. In total, 41 of the 62
patients were found to have a mood disorder according to DSM-III-R, i.e. a major
depressive disorder or dysthymia. Two patients were found to have already had a
diagnosis of major depression assigned to them in stage 1, but they were joined
by 13 more patients. A further 26 patients were found to be suffering from
dysthymia, nine had adjustment disorders with depressed mood, and 12 patients
showed no signs of depressed mood. For the group suffering from a current episode
of major depression or dysthymia, the prevalence rate increased to 11.7% in the
initial total population after stage 2. The diagnostic category with the highest
rate of depressed patients was 'musculoskeletal diseases'. Patients with masked
depression had higher scores for alexithymia and psychasthenia than depressed
patients who were directly diagnosed.
PMID- 9761405
TI - Regional differences in the use of psychiatric hospital beds in Finland: a
national case-register study.
AB - We investigated the possible differences in the utilization of psychiatric
hospital beds among five social security areas in Finland, and the association
between the variables related to the psychiatric services and the use of hospital
beds. The use of hospital beds varied quite distinctly among these areas, as did
the total rate of in-patients, readmissions, and rates of in-patients with
psychotic and affective disorders. The treatment practices appeared to vary as
the length of stay (LOS) and the rate of committal differed regionally in a
significant manner. There was a significant positive correlation between the
total rate of in-patients and the rate of readmitted patients (r=0.92, P<0.001),
and a significant negative correlation between the number of visits per worker in
out-patient care and the rate of readmissions (r=-0.94, P<0.001).
PMID- 9761406
TI - A 16-year follow-up study of schizophrenia and related disorders in Sofia,
Bulgaria.
AB - A total of 60 patients with functional non-affective psychoses were assessed 16
years after their inclusion in the WHO co-ordinated study on reduction and
assessment of psychiatric disability. All patients at inclusion had a recent
onset of a psychotic disorder. About one-third of the patients had a good
outcome. The rest showed moderate to severe psychiatric symptoms and social
disability. Comparison with other similar studies suggested that our results show
a low mortality rate, high levels of clinical symptoms, high levels of social
disability and a low percentage of institutionalized patients. These findings are
discussed in the context of the high level of family involvement in patients'
care, which could reflect a cultural factor.
PMID- 9761407
TI - Repetition of parasuicide--ICD-10 personality disorders and adversity.
AB - Patients with a history of previous parasuicide were compared to those who had
made their first attempt. A scale for suicidal ideation derived from the Scaled
Version of the General Health Questionnaire was completed by patients. ICD-10
personality disorder diagnoses were derived from the Standardized Assessment of
Personality which was administered to knowledgeable informants. Logistic
regression showed that unemployment, increasing severity of suicidal ideation,
previous psychiatric treatment and borderline personality disorder increased the
risk of reports of previous parasuicide. Anankastic personality disorder
decreased the risk of reports of previous parasuicide. Unemployment and specific
personality disorders have independent risks for repetition of parasuicide.
Specific ICD-10 personality disorders may increase or decrease the risk for
repetition of parasuicide.
PMID- 9761408
TI - Suicides hidden among undetermined deaths.
AB - The research phase of the National Suicide Prevention Project in Finland (from 1
April 1987 to 31 March 1988) included medico-legal investigation and
psychological autopsy of all deaths suspected of being suicides, including 1397
official suicides and 61 undetermined deaths. In later analyses on suicide,
undetermined cases were excluded. This paper presents an analysis of all
officially classified undetermined deaths (n = 139) over the study period,
consisting of all the initially suspected suicides (n = 61) and the remaining
undetermined deaths (n = 78) where suicide could not be excluded. Poisoning by
solids or liquids and drowning were the most common causes of all undetermined
deaths. Suicidal intent was observed in 87% of undetermined deaths initially
suspected of being suicides. In addition, 31% of these subjects had previously
attempted suicide, and 34% had made suicidal threats. Depression was diagnosed in
23% of cases and alcohol dependence or abuse in 31% of cases. Undetermined deaths
resembled suicides and appeared to reduce the suicide rate by 10%.
PMID- 9761409
TI - Development and preliminary application of a new scale for assessing
dysfunctional working models of self and others (DWM-S) in severely disturbed
patients.
AB - Although several suggestions have been made concerning the content and
characteristics of cognitive/emotive schemata held by people with different
disorders, there is still a scarcity of suitable instruments for verifying or
measuring such constructs. This is particularly true of schemata postulated to be
present in patients with personality disorders or a schizophrenic disorder. This
article deals with the development of a new scale for assessing dysfunctional
internal working models of self and others (DWM-S) in psychiatric patients.
Preliminary results obtained in a sample of patients (n=110) and healthy subjects
(n=40) suggest that the scale has a highly satisfactory internal consistency
(Cronbach's alpha=0.97), and satisfactory test-retest reliability (rho
coefficient=0.90 in healthy subjects and 0.86 in patients). Moreover, the DWM-S
is able to discriminate between patients and healthy subjects and between
patients suffering from various disorders. Further studies are in progress to
assess the cross-national generalizability of the findings obtained so far.
PMID- 9761410
TI - A comparison of the performance of rating scales used in the diagnosis of
postnatal depression.
AB - The results of a study looking into the association between thyroid status and
depression in the postpartum period were reanalysed to explore the psychometric
properties of the rating scales employed. The performance of the Edinburgh
Postnatal Depression Scale was found to be superior to that of the Hospital
Anxiety and Depression Scale in identifying RDC-defined depression, and on a par
with the observer-rated Hamilton Rating Scale for Depression, which it also
matched for sensitivity to change in mood state over time. The anxiety subscale
of the Hospital Anxiety and Depression Scale performed well, reflecting the fact
that anxiety represents a prominent symptom in postnatal depression.
PMID- 9761411
TI - TCI temperamental scores in bulimia nervosa patients and normal women with and
without diet experiences.
AB - In order to distinguish the trigger and the factors maintaining bulimia nervosa
(BN), TCI temperamental scores were compared among BN patients, normal controls
without diet experiences (N-N), and normal controls with diet experiences (N-D).
On the novelty-seeking (NS) scale, the BN patients scored significantly higher
than the N-N subjects, but there was no significant difference between the BN
patients and the N-D subjects, and the N-D subjects scored higher than the N-N
subjects. These findings suggest that high NS scores are related to diet
experiences rather than chronic bulimic symptoms.
PMID- 9761412
TI - Behaviour/emotional problems in male juvenile delinquents and controls in Russia:
the role of personality traits.
AB - Recent studies based on the psychobiological theory of personality by Cloninger
postulate a relationship between certain personality traits and various
psychopathological manifestations. To test this theory, we administered the
Temperament and Character Inventory and the Youth Self-Report to 188 male
delinquents from a juvenile correction centre in Northern Russia, and to 111 age
matched male controls recruited from among schoolchildren. As assumed by previous
studies, psychological symptoms were primarily positively correlated with harm
avoidance and negatively correlated with self-directedness. At the same time, the
higher levels of aggressive and delinquent behaviour were positively correlated
with novelty-seeking and negatively correlated with co-operativeness. The
possible mechanisms underlying these findings are discussed.
PMID- 9761413
TI - Debriefing with brief group psychotherapy in a homogenous group of non-injured
victims of a terrorist attack: a prospective study.
AB - This study describes a follow-up of 15 non-injured women, all from the same socio
economic background, who were exposed to a terrorist attack in Israel. All of the
women participated in group debriefing with brief group psychotherapy, involving
six meetings during the first 2 months following the event. Two days after the
attack, and 2 months and 6 months after the event, the women were administered a
post-traumatic stress disorder (PTSD) diagnostic scale, the Impact of Event Scale
(IES) and the SCL-90. At 6 months, four subjects (27%) were diagnosed with full
PTSD. The IES showed significantly higher scores at the first measure than at the
other two measures. Furthermore, the phobic anxiety subscale score immediately
after the event was significantly associated with the General Severity Index of
the SCL-90 and the severity of PTSD symptomatology at 6 months. The present paper
discusses the effectiveness of psychological intervention following trauma, and
raises questions concerning the need to invest public resources in this kind of
intensive intervention. Suggestions are proposed regarding the desired emphasis
of the psychological treatment in order to improve its benefits to victims.
PMID- 9761414
TI - Personality disorders and relationship to personality dimensions measured by the
Temperament and Character Inventory in patients with obsessive-compulsive
disorder.
AB - The occurrence of personality disorders was investigated in 36 patients with
obsessive-compulsive disorder by means of the SCID Screen questionnaire. In
addition, the personality dimensions were explored by means of the Temperament
and Character Inventory (TCI). In total, 75% of the patients fulfilled the
criteria for a personality disorder according to the SCID Screen questionnaire,
mostly (55%) within cluster C. Several significant correlations were found
between the separate personality disorders (PD) and subscales of the TCI, the
most pronounced being between avoidant and obsessive-compulsive PD and novelty
seeking and self-directedness. Strong correlations were also found between self
directedness and paranoid and borderline PD. In multiple regressions where the
presence of PD in clusters A, B and C, respectively, were used as dependent
variables and where the separate subscales of the TCI were used as independent
variables, the multiple R reached 0.68, 0.76 and 0.80 in clusters A, B and C,
respectively. Thus 46-64% of the variance in the personality disorder clusters
could be explained by the TCI subscales.
PMID- 9761415
TI - Severity of psychiatric disorder in day hospital and in-patient admissions.
AB - This study assessed whether severity of psychiatric disorder varies across day
hospital and in-patient units according to local need, and whether severity of
disorder predicts length of stay and therefore costs. Data were collected for a
consecutive series of 2230 in-patients and 712 day patients using the Social
Behaviour Scale (data completed by nurses) and diagnosis and Clinical Global
Impression (CGI) (completed by doctors). Severity of illness of subjects admitted
to in-patient units, but not to day hospitals, was associated with under
privileged area score (UPA). Length of in-patient stay is most accurately
predicted by Clinical Global Impression and six other variables relating to
diagnosis, demographic status and individual hospital. Improved resource
allocation for mental health services could be achieved if severity of disorder
was routinely collected.
PMID- 9761416
TI - Marijuana precipitation of panic disorder with agoraphobia.
AB - We report the case of a 16-year-old adolescent with the onset of a panic disorder
with agoraphobia after a first panic attack during marijuana intoxication. There
was a good response to standard cognitive behavioural therapy for panic disorder.
PMID- 9761417
TI - Enhancement of immobility in mouse forced swimming test by treatment with human
interferon.
AB - We investigated the depression induced by human interferons using the forced
swimming test in mice. Intravenous (i.v.) administration of interferon-alpha s
(natural interferon-alpha, recombinant interferon-alpha-2a and recombinant
interferon-alpha-2b, 600-60000 IU/kg) increased the immobility time in the forced
swimming test in a dose-dependent manner, but natural interferon-beta and
recombinant interferon-gamma-1a did not affect the immobility time. The increase
in the immobility time induced by recombinant interferon-alpha-2b peaked at 15
min after dosing. Administration of recombinant interferon-alpha-2b (6000 IU/kg,
i.v.) once daily for 7 consecutive days increased the immobility time, but
natural interferon-beta and recombinant interferon-gamma-la did not. Recombinant
interferon-alpha-2b in combination with the anti-depressants imipramine (10
mg/kg, i.p.) and mianserin (20 mg/kg, i.p.) did not increase the immobility time.
These results suggest that interferon-alpha has a greater potential for inducing
depression than interferon-beta and -gamma, and that anti-depressants are
effective against interferon-alpha-induced depression.
PMID- 9761418
TI - Functional determination of oxytocin affinity in near-term pregnant rat
myometrium: effect of chronic hypoxia.
AB - We designed the present study to determine: (1) if phenoxybenzamine can be used
as an irreversible blocker for oxytocin receptors, and as such to determine
oxytocin affinity, (2) if prolonged hypoxic exposure alters oxytocin receptor
coupling efficacy of oxytocin receptors to post-receptor mediated mechanisms in
the rat myometrium. Rats were exposed to room air (control), or to continuous
hypoxia (10.5% O2) from day 19 through day 21 (2-day exposure). On day 21, one
uterine horn was removed and used for in vitro study of myometrial contractile
responses to oxytocin, while the other was used for oxytocin receptor analysis.
In normoxic tissues, phenoxybenzamine (20 microM) decreased the maximum
contractile response (EMAX) to oxytocin (155+/-17 vs. 66+/-19 g s/cm2) and
oxytocin binding sites (BMAX: 253+/-35 vs. 114.9+/-21.3 fmol/mg protein). A
similar degree of reduction in EMAX and BMAX were observed in hypoxic tissues.
The oxytocin dissociation constant (KA) in the normoxic rat was 2.8+/-0.7 nM,
which was not different from the chronic hypoxic rat (3.3+/-0.9 nM). Analysis of
receptor occupancy-response curves indicated no oxytocin receptor reserve in both
normoxic and hypoxic myometrium. However, for a given fraction of the total
oxytocin receptors occupied, hypoxic tissue elicited a lower contractile response
to oxytocin. We conclude that: (1) phenoxybenzamine is a useful tool to
functionally study oxytocin receptor kinetics, (2) prolonged hypoxic exposure
does not affect the oxytocin affinity, (3) no spare receptors for oxytocin are
present in the rat myometrium, and (4) prolonged exposure to hypoxia decreases
oxytocin receptor-effector coupling efficiency in rat myometrium.
PMID- 9761419
TI - External carotid effects of 2-(2-aminoethyl)-quinoline (D-1997) in
vagosympathectomized dogs.
AB - Serotonin (5-hydroxytryptamine; 5-HT) elicits external carotid vasoconstriction
in vagosympathectomized dogs via 5-HT1B/1D receptors and a mechanism unrelated to
the 5-HT1, 5-HT2, 5-HT3 and 5-HT4 types. In order to further explore the nature
of this novel mechanism, the canine external carotid effects of 2-(2-aminoethyl)
quinoline (D-1997), a novel 5-HT1 receptor agonist, were analyzed and compared
with those of 5-HT and sumatriptan. Intracarotid (i.c.) infusions of 5-HT, D-1997
and sumatriptan to vagosympathectomized dogs dose-dependently decreased external
carotid conductance, the rank order of agonist potency being 5-HT > sumatriptan >
D-1997. The effects to D-1997 were resistant to intravenous (i.v.) pretreatment
with 5-HT2 and 5-HT3/5-HT4 receptor antagonists. Remarkably, the effects induced
by lower (10-100 microg/min), but not higher (300-1000 microg/min), doses of D
1997 were blocked by high doses of methiothepin (1 and 3 mg/kg, i.v.), as
previously shown with 5-HT. In addition, GR-127935 (1-10 microg/kg, i.v.),
partially and dose-dependently antagonized D-1997-induced responses. However, the
effects of D-1997 remained unaltered after blockade of alpha- and beta
adrenoceptors, muscarinic, nicotinic, histamine and dopamine receptors, or
inhibition of 5-HT-uptake or cyclo-oxygenase, depletion of biogenic amines or
blockade of Ca2+ channels. These results may support our previous contention that
lower doses of 5-HT elicit external carotid vasoconstriction in
vagosympathectomized dogs by activation of 5-HT1B/1D receptors, whilst higher
doses of 5-HT stimulate a novel vasoconstrictor mechanism.
PMID- 9761420
TI - Persistent release of noradrenaline caused by anticancer drug 4'-epidoxorubicin
in rat tail artery in vitro.
AB - Anthracycline derivatives including 4'-epidoxorubicin are known to cause
cardiovascular side effects. In this study we examined the effects of 4'
epidoxorubicin on sympathetic nerves of rat tail artery in vitro. Treatment with
4'-epidoxorubicin at concentrations higher than 10 microM gradually increased the
resting tension of the arterial strips, an effect which was greatly enhanced by
subsequent addition of 10 microM cocaine. This increase of the resting tension by
4'-epidoxorubicin was prevented by prazosin, suppressed in the arterial strips of
reserpine-pretreated rats, and reduced by superoxide dismutase. However,
tetrodotoxin and histamine receptor antagonists (diphenhydramine and cimetidine)
failed to influence it. The contractile response to electrical sympathetic
stimulation was slightly attenuated by 30 microM 4'-epidoxorubicin. 4'
epidoxorubicin did not shift the concentration-response curve for noradrenaline.
In the superfusion experiments, the basal release of noradrenaline was increased
approximately five-fold by 30 microM 4'-epidoxorubicin, and this increase was not
inhibited by 0.1 microM prazosin, 0.5 microM tetrodotoxin, 10 microM cocaine or
Ca2+-free medium. Noradrenaline release evoked by electrical stimulation was
gradually suppressed by 30 microM 4'-epidoxorubicin treatment. These results
suggest that 4'-epidoxorubicin directly acts on the sympathetic nerve to cause
persistent release of noradrenaline in rat tail artery.
PMID- 9761421
TI - Effects of pilsicainide and propafenone on vagally induced atrial fibrillation:
role of suppressant effect in conductivity.
AB - The effects of pilsicainide on vagally induced atrial fibrillation and on
electrophysiological parameters were compared with those of propafenone in alpha
chloralose-anesthetized dogs. Conduction velocity, effective refractory period,
wavelength, averaged atrial fibrillation cycle length and activation sequence in
the right atrial free wall were determined before and after drug administration.
Pilsicainide (2 mg/kg/5 min and 3 mg/kg/h)(n=10) or propafenone (2 mg/kg/15 min
and 4 mg/kg/h)(n=10) was intravenously infused during stable atrial fibrillation
sustaining > 30 min. Pilsicainide terminated atrial fibrillation in nine dogs,
while propafenone did so in three (p < 0.01). After the drug, conduction velocity
was suppressed more in the pilsicainide than in the propafenone group(p < 0.01).
There was no difference in effective refractory period after drug between the two
groups. Mean wavelength was prolonged from 46.0 to 70.4 mm in the pilsicainide
group and from 45.0 to 110.8 mm in the propafenone (p < 0.01 vs. pilsicainide).
Activation mapping during atrial fibrillation showed Type II or III atrial
fibrillation as previously defined [Konings, K.T.S., Kirchhof, C.J.H.J., Smeets,
J.R.L.M., Wellens, H.J.J., Penn, O.C., Allessie, M.A., 1994. High-density mapping
of electrically induced atrial fibrillation in humans. Circulation. Vol. 89, pp.
511-521.] before the drug, and changed to Type I before atrial fibrillation
termination. Thus, pilsicainide was more effective to terminate vagally induced
atrial fibrillation than was propafenone despite a greater effect of propafenone
than of pilsicainide on wavelength. In this canine atrial fibrillation model, the
suppression of conduction velocity may play an important role in changing the
activation pattern of atrial fibrillation and thus, terminating atrial
fibrillation.
PMID- 9761422
TI - Effect of xanthine oxidase inhibition on endothelium-dependent and nitrergic
relaxations.
AB - The effects of inhibition of xanthine oxidase on responses mediated by nitric
oxide (NO) were examined using the selective xanthine oxidase inhibitors
allopurinol and 4-amino-6-hydroxypyrazolo[3,4-d]pyrimidine (AHPP). In rat aortic
rings precontracted with phenylephrine (1 microM), allopurinol (300 microM) and
AHPP (100, 300 microM) significantly reduced tone, an effect not seen after
inhibition of NO synthase with Nomega-nitro-L-arginine (NOLA 100 microM).
Relaxations produced by acetylcholine (0.01-10 microM) were significantly
enhanced by AHPP (100, 300 microM) but not by allopurinol. Nitrergic relaxations
in the rat anococcygeus muscle (field stimulation 1 ms pulses; 1 Hz: 10 s) were
not affected by either allopurinol or AHPP. However, relaxations produced by
exogenous NO (0.25 microM) were significantly enhanced by AHPP, allopurinol (100
microM) and superoxide dismutase (100 U/ml). Xanthine (500 microM) partially, but
significantly, reversed the enhancement produced by AHPP. These findings suggest
that superoxide generated by xanthine oxidase modulates the activity of basal and
stimulated NO derived from the rat aortic endothelium, but does not affect the
activity of the nitrergic transmitter in the rat anococcygeus muscle, despite its
ability to modulate responses to exogenous NO.
PMID- 9761423
TI - In vitro comparison of two NONOates (novel nitric oxide donors) on rat pulmonary
arteries.
AB - The pulmonary vasorelaxant properties of two NONOates (diazeniumdiolates) were
examined because this novel group of nitric oxide (NO) donors may be useful in
pulmonary hypertension. MAHMA NONOate ((Z)-1-?N-Methyl-N-[6-(N
methylammoniohexyl)amino]? diazen-1-ium-1,2-diolate) and spermine NONOate ((Z)- 1
?N-[3-aminopropyl]-N-[4-(3-aminopropylammonio)butyl]-amino?di azen-1-ium-1,2
diolate) decomposed at different rates (half-lives 1.3 min and 73 min,
respectively; 37 degrees C, pH 7.3) but generated the same total amount of NO.
They fully relaxed submaximally contracted ring preparations of main and
intralobar pulmonary arteries from rats. Responses were inhibited by the
guanylate cyclase inhibitor, ODQ (1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one).
Potency was not affected by choice of contractile spasmogen (phenylephrine,
endothelin-1, thromboxane-mimetic) or endothelium removal, and tolerance did not
develop; thus the drugs had properties important for use in pulmonary
hypertension. MAHMA NONOate was 10-40-fold more potent than spermine NONOate but
responses to spermine NONOate were more sustained (spermine NONOate > 60 min;
MAHMA NONOate < 7 min). It is concluded that the differences in potency and time
course reflect the different rates of NO generation by these NONOates.
PMID- 9761424
TI - Alpha2-adrenoceptors mediate the effect of dopamine on adult rat jejunal
electrolyte transport.
AB - The present study was aimed to characterise the effect of dopamine on rat jejunal
electrolyte transport and to evaluate the type of receptors and the intracellular
signalling mechanisms involved in the response. Stripped epithelial sheets were
mounted in Ussing chambers connected to an automatic voltage current clamp and
changes in the short circuit current (microA/cm2) were measured continuously as
an index of electrogenic ion transfer. Dopamine (0.1-100 microM) produced a
concentration dependent decrease in Isc with an EC50 of 1.4+/-0.1 microM: the
effect of dopamine was not changed by propranolol (1 microM), prazosin (1 microM
and 10 microM) or (+/-)-sulpiride (1 microM). but was completely abolished by
phentolamine (1 microM). The addition of phentolamine (0.3 microM) or yohimbine
(0.3 microM) produced a rightward shift of the dopamine concentration-dependent
curve with an increase in EC50 values up to 30.0+/-0.2 microM and 11.7+/-0.1
microM. respectively. The alpha2-adrenoceptor-selective agonist, UK14,304 (5
bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine), also produced a
concentration-dependent decrease in Isc with an EC50 of 0.04+/-0.01 microM; the
addition of yohimbine (0.3 microM) increased the EC50 value of UK14,304 to 0.68+/
0.01 microM. The addition of amiloride (100 microM), a Na+ channel blocker, to
the fluid bathing the apical side was found not to change the effect of dopamine
on Isc. 5-(N-ethyl-N-isopropyl)-amiloride (10 microM), a selective Na+/H+
exchanger inhibitor, partially antagonised the effect produced by 100 microM of
dopamine. The addition of ouabain (1 mM) to the fluid bathing the basal side,
antagonised the effect produced by 50 and 100 microM of dopamine. In contrast,
frusemide (1 mM) completely abolished the effect of all concentrations of
dopamine. Forskolin (10 microM) and N6,2'-O-dibutyryl cyclic AMP (1 mM) added to
both the apical and serosal sides completely abolished the effect of dopamine on
Isc. It is concluded that the dopamine antisecretory effects in the jejunum of
adult rats are mediated through alpha2-adrenoceptors. This effect is sensitive to
increases in intracellular cyclic AMP and is primarily dependent on the basal
Na+,K+,2Cl- -co-transport mechanism.
PMID- 9761425
TI - Effects of LEX032, a novel recombinant serine protease inhibitor, on N(G)-nitro-L
arginine methyl ester induced leukocyte-endothelial cell interactions.
AB - We studied the effects of LEX032, a novel serine protease inhibitor, on N(G)
nitro-L-arginine methyl ester (L-NAME) induced leukocyte-endothelium interactions
in vivo, utilizing intravital microscopy of the rat mesentery. Superfusion of the
rat mesentery with 50 microM L-NAME, a nitric oxide (NO) inhibitor, for 90 min
resulted in a significant and time-dependent increase in leukocyte rolling,
leukocyte adherence, and transmigration of leukocytes, compared to control rats
superfused with Krebs-Henseleit (K-H) solution. However, systemic administration
of LEX032 (15 mg/kg bolus injection followed by a 15 mg/kg per hour infusion) to
L-NAME superfused rats significantly attenuated leukocyte rolling and adherence
along the venular endothelium of the rat mesentery, and also inhibited
transmigration of leukocytes through the microvascular endothelial wall.
Moreover, no significant changes were observed in mean arterial blood pressure or
local venular shear rates following systemic administration of LEX032. Our data
demonstrate that systemic inhibition of serine proteases by LEX032 reduces
enhanced leukocyte-endothelium interactions provoked by inhibition of NO
synthesis. These results also explain some of the beneficial effects exerted by
serine protease inhibitors in ischemia-reperfusion and other inflammatory states.
PMID- 9761426
TI - Cyclooxygenase 2 expression by endothelin-1-stimulated mouse resident peritoneal
macrophages in vitro.
AB - Macrophages have been shown to produce endothelin and to play a role in the
pathogenesis of neural damage after cerebral ischemia or vasospasm after
subarachnoid hemorrhage. Cyclooxygenase 2 is induced during inflammation
following brain insult and participates in inflammation-mediated neurotoxicity.
However, it has not yet been established how endothelin-1 acts on cyclooxygenase
2 expression in macrophages. In the present study, we examined the effects of
endothelin-1 on cyclooxygenase 2 expression and prostaglandin E2 production, and
the effects of endothelin ET(A) and ET(B) receptor antagonists. Stimulation by
endothelin-1 ranging from 10(-11) to 10(-9) M time and dose dependently increased
the production of prostaglandin E2 and the expression of cyclooxygenase 2 protein
without changing that of cyclooxygenase 1 protein, an effect which was inhibited
by dexamethasone, nonsteroidal anti-inflammatory drugs and the selective
endothelin ET(B) receptor antagonist, BQ788 (N-cis-2,6-dimethylpiperidinocarbonyl
L-gamma-methyl-leucyl-D-L-me thoxycarbonyl-tryptophanyl-D-norleucine). The
selective endothelin ET(A) receptor antagonist, BQ123 [cyclo (D-Trp-D-Asp-Pro-D
Val-Leu)] also inhibited these reactions, but its potency was less than that of
the selective endothelin ET(B) receptor antagonist. Endothelin ET(A) and ET(B)
receptor antagonists had no effects on cyclooxygenase 2 protein expression and
prostaglandin E2 production in lipopolysaccharide-stimulated macrophages. We
conclude that endothelin-1 increases cyclooxygenase 2 protein expression and
prostaglandin E2 production via mainly endothelin ET(B) receptors and partly
endothelin ET(A) receptors in macrophages; however, lipopolysaccharide increases
both cyclooxygenase 2 protein expression and prostaglandin E2 production in
pacrophages without involving endothelin ET(A) or ET(B) receptor-mediated
processes.
PMID- 9761428
TI - Medium change amplifies mitogen-activated protein kinase-mediated prostaglandin
E2 synthesis in Swiss 3T3 fibroblasts.
AB - In Swiss 3T3 fibroblasts, changing the culture medium prior to stimulation
resulted in an augmentation of bradykinin-induced prostaglandin E2 synthesis. The
augmentation depended on the duration of the exposure to the fresh medium, with a
maximum effect at 1 h. Fetal calf serum in the fresh medium was essential for
augmented prostaglandin E2 synthesis. The medium change slightly augmented the
bradykinin-induced increase in intracellular free Ca2+ concentration and
phosphoinositide hydrolysis with a different time course from that for
prostaglandin E2 synthesis. 4',5,7-Trihydroxyisoflavone (genistein) and 3,4
dihydroxybenzylidene-malononitrile (tyrphostin 23), inhibitors of tyrosine
kinases, and 2'-amino-3'-methoxyflavone (PD98059), an inhibitor of mitogen
activated protein kinase (MAPK) kinase, attenuated the increase in prostaglandin
E2 synthesis. Bradykinin caused phosphorylation of cytosolic phospholipase A2 and
p42/p44 MAPK, which was augmented by the medium change. From the results, it is
concluded that activation of MAPK and cytosolic phospholipase A2 is involved in
the augmentation of prostaglandin E2 synthesis produced by the medium change.
PMID- 9761427
TI - Dialdehyde sesquiterpenes and other terpenoids as vanilloids.
AB - Selected naturally occurring unsaturated dialdehyde sesquiterpenes and related
bioactive terpenoids were assayed for vanilloid-like activity. Out of the 25
compounds tested, eight inhibited completely the specific binding of
[3H]resiniferatoxin by rat spinal cord membranes: binding affinities ranged from
0.6 microM for cinnamodial to 19.0 microM for hebelomic acid F. These values were
comparable to the binding affinity of capsaicin (2.7 microM). With the exception
of four ligands, compounds that inhibited resiniferatoxin binding to rat spinal
cord membranes were also pungent on the human tongue where they showed cross
tachyphylaxis with capsaicin. As expected from their reactive nature, these
compounds possess additional sites of action, as reflected in the complex
behavior of the stimulation of calcium influx by cinnamodial and cinnamosmolide
at high concentrations. This observation might explain the unexpectedly weak
membrane depolarization by cinnamodial compared to capsaicin. We conclude that a
range of sesquiterpene dialdehydes and related terpenoids, both pungent and non
pungent, may function as vanilloids. These compounds may represent a new chemical
lead for the development of vanilloid drugs, structurally unrelated to either
capsaicin or resiniferatoxin.
PMID- 9761429
TI - Cardiac surgery beyond the Urals.
PMID- 9761430
TI - Pulmonary artery stenosis after systemic-to-pulmonary shunt operations.
AB - OBJECTIVE: Systemic-to-pulmonary shunt operations are still required for
palliation of certain congenital heart defects. The aim of this study was to
analyze the incidence and etiology of the development of pulmonary artery
stenosis after these procedures. METHODS AND RESULTS: Pre- and post-operative
angiograms of 59 patients who underwent 54 peripheral and 12 central shunt
operations were analyzed retrospectively. Patients without prior cardiovascular
interventions (group I, n = 47) were differentiated from patients with prior
interventions (group II, n = 12). In group I, all peripheral shunts were inserted
contralaterally to the ductus arteriosus. Follow-up for all patients was 1.8
years (4 days-7.8 years). Pulmonary artery stenosis was diagnosed in 12/59
patients (20.3%, group I 12/47; group II 0) after a time interval of 4 days up to
5.3 years and only after Blalock-Taussig shunts (one classical, 11 modified)
(12/40 = 30%). The stenoses were located ipsilaterally to the shunt in 7/12 and
contralaterally in 5/12. Statistical analysis did not show any impact of age,
weight, sex, shunt type or size, pulmonary artery diameters, Nakata and McGoon
indices and prior interventions on the development of pulmonary artery stenosis.
However, a patent ductus arteriosus and administration of Prostaglandin E1 had a
significant impact on the development of pulmonary artery stenosis on the side of
the ductus arteriosus. CONCLUSION: Pulmonary artery stenosis is not a rare event
after systemic-to-pulmonary shunt operations. A patent ductus arteriosus with or
without administration of Prostaglandin E1 is related to pulmonary artery
stenosis on the side of the ductus arteriosus. Pulmonary artery stenosis on the
side of a peripheral shunt may be caused by inappropriate surgical technique,
increased intimal proliferation, or pulmonary artery kinking. Treatment depends
on severity of cyanosis and on further surgical plans.
PMID- 9761431
TI - Results of primary and two-stage repair of interrupted aortic arch.
AB - OBJECTIVE: Early results of primary and two-stage repair of interrupted aortic
arch have improved. Experience with different surgical approaches should be
analysed and compared. METHODS: Forty neonates and infants with interrupted
aortic arch underwent primary repair (19 patients) or palliative operation (21
patients). Twenty (50%) patients were followed-up for 5.1+/-4.3 years. All
patients were regularly examined with the aim of determining clinical
development, presence of residual lesions or complications and need for re
intervention. Aortic arch and the left ventricular outflow tract growth were
assessed by echocardiographic examination. Data from hospital and outpatient
department records were analysed. RESULTS: The early mortality was 61.9% after
palliative operations and 36.8% after the primary repair. Presence of
complications (P < 0.001), earlier year of surgery (P < 0.01), bad clinical
condition and acidosis (P < 0.05) represented statistically significant risk
factors for death in the whole series. In seven (87.5%) out of eight early
survivors, after the initial palliative operation, closure of ventricular septal
defect and debanding were done, and in three (37.5%) patients, re-operation for
aortic arch obstruction was also required. Out of 12 patients, after the primary
repair, one required early re-operation for persistent left ventricular outflow
tract obstruction and two needed late re-intervention for left bronchus
obstruction. In three (25%) patients, after the primary repair, left ventricular
outflow tract obstruction with a maximal systolic pressure gradient higher than
30 mmHg developed. At present, all 20 early survivors are alive. Five patients,
after palliative operation, are in NYHA class 1, but in three patients, who are
in class III or IV, the outcome is influenced by severe complications. All
patients after the primary repair are in class I or II. CONCLUSIONS: Our
experience confirmed better results after the primary repair of interrupted
aortic arch, which was associated with lower mortality, prevalence of severe
complications and need for re-intervention. Higher prevalence of subaortic
stenosis after primary repair could be explained by patient selection early in
our experience. We recommend the primary repair of interrupted aortic arch and
associated heart lesions in neonates, however, in unfavourable conditions an
individualised surgical approach with initial palliative surgery should be
considered.
PMID- 9761433
TI - Contribution of the interventricular septum to maximal right ventricular
function.
AB - OBJECTIVE: Maximal right ventricular (RV) function is influenced by left heart
hemodynamics, possibly mediated by the interventricular scpturn (IVS). We
examined the potential contribution of the IVS function to right heart function.
METHODS: In 12 canine isovolumic right heart preparations, incremental volumes
were introduced into a high compliance RV balloon until RV failure occurred.
Maximal RV developed pressure (RVDP) and maximal positive RV dP/dt were
determined with a working IVS at a constant left ventricular (LV) output of 2
l/min and at a constant mean arterial pressure of 80 mmHg. Thereafter the IVS was
thermally inactivated, and measurements were repeated using the same protocol.
RESULTS: At constant arterial pressure and constant LV output, thermal
inactivation of the IVS led to a significant decrease in maximal RVDP
(inactivated vs. working IVS: 36.1+/-9.8 vs. 56.8+/-16.2 mmHg, respectively, P <
0.001), and RV dP/dt (inactivated vs. working IVS: 720+/-220 vs. 1350+/-190
mmHg/s, respectively, P < 0.001). CONCLUSIONS: These results suggest that the
functional status of the IVS is a major determinant of maximal RV function. At
constant LV conditions and arterial pressure, an inactivated IVS leads to a
significant decrease in maximal RVDP and RV dP/dt under the conditions of this
study.
PMID- 9761432
TI - Myocardial protection by pressure- and volume-controlled continuous hypothermic
coronary perfusion in combination with Esmolol and nitroglycerine for correction
of congenital heart defects in pediatric risk patients.
AB - OBJECTIVE: This study assesses the technical applicability and the clinical value
of the continuous coronary perfusion with oxygenated blood as a method for
myocardial protection used for congenital heart surgery in pediatric risk
patients. METHODS: Thirty non-consecutive pediatric risk patients aged from 1
month to 16 years (mean 3.9 years; 11/30 patients aged <6 months) underwent open
heart procedures on the beating heart for simple and complex cardiac
malformations using a self designed perfusion system with pressure- and volume
controlled continuous hypothermic coronary perfusion (PVC-CONTHY-CAP) in
combination with ultra-short beta1-receptor blockade (Esmolol) and nitroglycerine
for myocardial protection. The following procedures were done: VSD patch closure
(n = 6), repair of total a-v canal with 'double patch' (n = 4), total repair of
tetralogy of Fallot (n = 7), correction of truncus arteriosus communis type IV (n
= 1), mitral valve reconstruction (n = 4), total cavo-pulmonary connection (n =
4), and Rastelli procedure (n = 4). RESULTS: The mean cardio-pulmonary bypass
time was 131.5 min (range: 44-245 min), the mean coronary perfusion time: 90.1
min (range: 13-202 min). The weaning off extracorporeal circulation was
uneventful in all patients, in 21 patients with low-dose and in nine patients
with moderate catecholamine support: the mean weaning time was 25 min (range: 7
58 min). The post-operative mean peak creatine kinase (CK-MB) value was 58 U/l,
(range: 14-202 U/l). The mean ICU stay in the cardiac surgery unit was 2.9 days,
(range: 1-10 days). The mean post-operative mechanical ventilatory support was 2
days (range: 6 h-9 days). Six patients developed thrombocytopenia with values <40
tsd/microl, four patients renal dysfunction, two patients ascites, five patients
heart rhythm disturbances, one patient neurological deficits. In three patients
(VSD closure: n = 2; age: 1 and 2 months; total a-v-canal: n = 1; age: 3 months)
re-do procedures for significant intraventricular shunt had to be done, in one
patient implantation of a permanent pacemaker system was necessary. One patient
died due to multiple organ failure after uneventful surgery (total cavo-pulmonary
connection for single ventricle). CONCLUSIONS: PVC-CONTHY-CAP can be successfully
used for repair of simple and complex congenital cardiac malformations. However,
in children less than 3 months of age, the transatrial repair of intraventricular
defects is technically much more demanding and challenging than under
conventional cardioplegic arrest and is possibly accompanied by an increased
incidence of residual or recurring intraventricular shunts.
PMID- 9761434
TI - Advantage of post-operative oral administration of UFT (tegafur and uracil) for
completely resected p-stage I-IIIa non-small cell lung cancer (NSCLC).
AB - OBJECTIVE: Although adjuvant therapy after surgery for non-small cell lung cancer
(NSCLC) has been reported to be ineffective, it has been recently reported in
prospective randomised studies conducted by two different groups in Japan that
oral administration of a 5-fluorouracil (5-FU) derivative drug, UFT (a
combination drug of tegafur and uracil) can improve the post-operative survival
[The Study Group of Adjuvant Chemotherapy for Lung Cancer (Chubu, Japan). A
randomized trial of postoperative adjuvant chemotherapy in non-small cell lung
cancer (the second cooperative study). Eu J Surg Oncol 1995;21:69-77; Wada, H.,
Hitomi, S., Teramatsu, T, West Japan Study Group for Lung Cancer Surgery.
Adjuvant chemotherapy after complete resection in non-small-cell lung cancer. J
Clin Oncol 1996;14:1048-1054]. To examine the efficacy of UFT as post-operative
adjuvant therapy, a retrospective study was performed. METHODS: A total of 655
consecutive patients who underwent complete tumor resection for pathologic stage
I-IIIa, NSCLC at the Department of Thoracic Surgery, Chest Disease Research
Institute, Kyoto University between 1976 and 1992 were retrospectively reviewed.
As post-operative adjuvant therapy, UFT was administrated to 98 patients (UFT
group), and was not administered to the other 557 patients (Control group).
RESULTS: The 5-year survival rate of the UFT group was 76.5%, which was
significantly better than that of the Control group (5-year survival rate: 58.6%,
P = 0.005). Stratified with pathologic stage, the efficacy of UFT was seen in the
p-stage I disease (5-year survival rate: 88.6% for the UFT group, 72.0% for the
Control group, P = 0.013) and in the p-stage IIIa, pN2 disease (5-year survival
rate: 54.3% for the UFT group, 37.5% for the Control group, P = 0.037).
Multivariate analysis of the prognostic factors also revealed the efficacy of UFT
(P = 0.004, 95% confidence interval of relative risk: 0.325-0.840). Post
operative intravenous chemotherapy or radiation therapy did not prove to be
significant factors affecting the prognosis. CONCLUSIONS: Efficacy of oral
administration of UFT as post-operative adjuvant therapy for completely resected
NSCLC was proposed. To confirm the efficacy, a prospective randomized study for a
more homogenous patient group is needed.
PMID- 9761436
TI - Repeat mediastinoscopy in the staging of lung cancer.
AB - OBJECTIVE: Despite technical difficulties due to mediastinal fibrosis, repeat
mediastinoscopy can be a valuable tool in the restaging of lung cancer. It
provides essential pathological information on mediastinal invasion when
selecting patients for surgical resection after induction chemotherapy in stage
IIIa disease. The aim of our study was to evaluate the feasibility, sensitivity
and accuracy of repeat mediastinoscopy. METHODS: From 1994 to 1997 we performed a
repeat mediastinoscopy in 15 patients (13 men, two women) with bronchogenic
carcinoma. Their age ranged from 49 to 75 years. (mean 64.7). Seven patients had
induction chemotherapy for a non-small cell bronchogenic carcinoma with positive
N2 nodes on mediastinoscopy. Four patients had a second primary contralateral
lung cancer, one had a locoregional recurrence of bronchogenic carcinoma. The
other three had a first mediastinoscopy for other reasons than lung cancer,
repeat mediastinoscopy being performed for staging of malignant disease. RESULTS:
In all 15 patients it was possible to perform a complete repeat mediastinoscopy.
In one patient repeat mediastinoscopy turned out to be false negative, so, in our
series, sensitivity was 87.5%, specificity 100% and accuracy 93.7%. CONCLUSION:
Previous mediastinoscopy is no contraindication for a repeat one. Repeat
mediastinoscopy offers valuable pathological information in restaging of lung
cancer.
PMID- 9761435
TI - CT-guided methylene-blue labelling before thoracoscopic resection of pulmonary
nodules.
AB - OBJECTIVE: Evaluation of the efficiency of our technique of methylene-blue
labelling of pulmonary nodules to facilitate thoracoscopic recognition and
excision. DESIGN: Patients with a peripheral pulmonary nodule smaller than 2.5 cm
and not in contact with the visceral pleura were included. Under
tomodensitometric guidance, the nodules were labelled with methylene-blue within
hours before thoracoscopic wedge resection. If frozen section revealed a primary
bronchial carcinoma, thoracotomy and classical resection were performed during
the same anesthesia. RESULTS: Between July 1992 and August 1996, 54 nodules were
removed in 51 patients. Labelling was performed between 75 and 270 min before
surgery and was complicated in 13 patients (25.4%) by a small pneumothorax
without any clinical consequence. Labelling allowed successful thoracoscopic
recognition of 50 nodules (92%) and thoracoscopic wedge resection was possible in
all but one cases (91%). Five patients (9%) required thoracotomy. Histology
showed a benign lesion in 22 cases, a primary lung carcinoma in 17 and a
metastases in 15. Twenty of the 22 benign nodules (91%) were removed without
thoracotomy. According to the protocol, 13 patients with a primary lung tumour
underwent lobectomy during the same session. There was no mortality nor morbidity
amongst patients who had thoracoscopy only. CONCLUSIONS: Our technique of
labelling peripheral pulmonary nodules with methylene-blue is very effective and
is not associated with any relevant complication. Thoracoscopic excision and
diagnosis is possible in more than 90% of the cases. We therefore recommend this
simple, low-cost and reliable technique for nodules not in contact with the
visceral pleura before thoracoscopic wedge resection.
PMID- 9761437
TI - Less invasive approaches for closed mitral commissurotomy.
AB - OBJECTIVE: Recently, closed mitral commissurotomy (CMC) has been reexplored due
to the concepts of less invasive valvular surgery. The feasibility of closed
mitral commissurotomy via port access or limited thoracotomy by aid
transesophageal echocardiography (TEE) was investigated in this clinical study.
METHODS: Between August 1996 and April 1998, 42 patients (32 women, ten men with
a mean age of 36.2+/-7.8 years) underwent less invasive CMC at the Kosuyolu Heart
and Research Hospital. CMC procedure were done through a limited (12-16 cm)
thoracotomy incision in 23 patients, a very limited or mini thoracotomy incision
(7-8 cm) in 11 patients and port access by aid TEE in eight patients.
Preoperative mean mitral valve area was calculated as 1.19+/-0.13 cm2 and mean
mitral valve gradient was measured as 14.8+/-3.2 mmHg. TEE provided information
about the mitral valve anatomy and functions during the procedure in all
patients. RESULTS: Commissurotomy was successfully performed in all patients. In
eight patients, a Tubbs dilator was inserted via port access at the 6th
intercostal space from a 3-cm incision. Incision by guidance of TEE and CMC could
be performed without thoracotomy in five patients. In three patients of the port
access group, a very limited thoracotomy was required to perform CMC by digital
guidance. Postoperative mean MVA was 2.37+/-0.29 cm2, minimal mitral gradient was
5.3+/-1.7 mmHg. In eleven patients, minimal mitral regurgitation was observed.
The operations and postoperative period were free of complications in all
patients. Following an average 12+/-2.8 h intensive care unit period, all
patients were discharged after an average of 3.4+/-0.8 days of hospitalization.
CONCLUSION: Limited thoracotomy has less detrimental structural effects in
patients. Port access by aid TEE approach to CMC may offer less invasiveness,
lower cost effectiveness and be an alternative to percutaneous balloon mitral
valvotomy.
PMID- 9761438
TI - Tissue engineering of heart valves--human endothelial cell seeding of detergent
acellularized porcine valves.
AB - OBJECTIVE: Tissue engineering of heart valves represents a new experimental
concept to improve current modes of therapy in valvular heart disease. Drawbacks
of glutaraldehyde fixed tissue valves or mechanical valves include the short
durability or the need for life-long anticoagulation, respectively. Both have in
common the inability to grow, which makes valvular heart disease especially
problematic in children. The aim of this study was to develop a new methodology
for a tissue engineered heart valve combining human cells and a xenogenic
acellularized matrix. METHODS: Porcine aortic valves were acellularized by
deterging cell extraction using Triton without tanning. Endothelial cells were
isolated in parallel from human saphenous veins and expanded in vitro. Specimens
of the surface of the acellular matrix were seeded with endothelial cells.
Analysis of acellularity was performed by light microscopy and scanning electron
microscopy. Cell viability following seeding was assayed by fluorescence staining
of viable cells. RESULTS: The acellularization procedure resulted in an almost
complete removal of the original cells while the 3D matrix was loosened at
interfibrillar zones. However the 3D arrangement of the matrix fibers was grossly
maintained. The porcine matrix could be seeded with in vitro expanded human
endothelial cells and was maintained in culture for up to 3 days to document the
formation of confluent cultures. CONCLUSIONS: Porcine aortic valves can be almost
completely acellularized by a non-tanning detergent extraction procedure. The
xenogenic matrix was reseeded with human endothelial cells. This approach may
eventually lead to the engineering of tissue heart valves repopulated with the
patients own autologous cells.
PMID- 9761439
TI - The effects of mechanical cardiac stabilization on left ventricular performance.
AB - OBJECTIVE: Mechanical cardiac stabilization is beneficial for precise coronary
anastomoses on the beating heart. However, the effect of mechanical cardiac
stabilization on hemodynamics, left ventricular performance, and the degree of
injury to underlying tissue are uncertain. METHODS: Twelve swine (20-30 kg)
underwent median sternotomy and a mechanical stabilizing device (United States
Surgical, Norwalk, CT) was positioned astride a segment of left anterior
descending coronary artery (LAD). Coronary blood flow was measured by Doppler.
Sonomicrometry crystals were placed distal to the stabilizer in a region of
myocardium subtended by the LAD, and a left ventricular micromanometer was
inserted. Regional myocardial function was determined using the preload
recruitable stroke work (PRSW) relationship. Data were acquired at three time
points: 20 min before (PRE) and after placing the stabilizer (EXPT); and 20 min
after removing the stabilizer (POST). Tissue subjacent to the stabilizer was then
biopsied. Means +/- standard deviation are reported. RESULTS: The mechanical
stabilizer caused a decrease in cardiac output from 4.2+/-1.5 to 3.6+/-1.3 l/min
(P < 0.05), which returned to baseline values after its removal. Regional
myocardial function (percent systolic shortening and MW and x-intercept of the
PRSW relationship) was unchanged. Blood pressure, heart rate, and LAD blood flow
remained constant. Histologic findings included a layer of myocyte necrosis less
than 1 mm in depth immediately beneath the stabilizer. CONCLUSIONS: These data
demonstrate that mechanical stabilization of the LAD may temporarily decrease
cardiac output. This is not attributed to impaired contractility or ischemia, but
is secondary to direct ventricular compression with reduced stroke volume. Injury
to underlying tissue is negligible.
PMID- 9761440
TI - Soluble adhesion molecules in reperfusion during coronary bypass grafting.
AB - OBJECTIVE: Adhesion of activated leukocytes to the endothelial cells as a result
of myocardial ischaemia/reperfusion during open chest coronary artery surgery has
been shown to be involved in the development of tissue damage. Activated
leukocytes adhere to endothelium via adhesion molecules expressed by both cell
types, resulting in the impairment of coronary capillary flow. Upon cell
activation, adhesion proteins may be released in the soluble form to circulating
blood. The purpose of our study was to verify whether myocardial
ischaemia/reperfusion occurring during coronary artery bypass grafting results in
release of the soluble adhesion molecules VCAM-1, ICAM-1, E-selectin and L
selectin into the circulation. METHODS: Plasma levels of the soluble adhesion
molecules were measured in vein, arterial and coronary sinus blood samples taken
from 15 patients undergoing coronary artery bypass grafting (CABG). Blood samples
for estimations were collected during the procedure: before aorta cross-clamping,
at the beginning of reperfusion and 30 min after reperfusion. Soluble adhesion
molecules levels were measured by standard ELISA assays. RESULTS: Mean plasma
levels of soluble VCAM-1 in arterial samples increased significantly at the
beginning of reperfusion and 30 min after reperfusion. In contrast, soluble L
selectin plasma levels in arterial samples remained unchanged. In coronary sinus
samples, levels of soluble ICAM-1 significantly increased 30 min after
reperfusion. Moreover, in coronary sinus samples collected 30 min after
reperfusion, soluble ICAM-1 levels were significantly higher than in arterial
samples obtained at the same time. The mean concentration of soluble E-selectin
in samples obtained from coronary sinus decreased significantly 30 min after
reperfusion. Moreover, plasma levels of soluble E-selectin in coronary sinus
samples obtained 30 min after reperfusion were significantly decreased compared
with these observed in arterial samples collected at the same time. CONCLUSIONS:
The reperfusion of ischaemic myocardium during CABG results in a significant
increase in plasma levels of the soluble endothelial adhesion molecules VCAM-1
and ICAM-1 and significant decrease in soluble E-selectin plasma levels. L
selectin plasma levels during CABG procedure remain unchanged. We propose that
the increased plasma concentrations of soluble VCAM-1 and ICAM-1 are a result of
endothelial cell activation during ischaemia/reperfusion following bypass
surgery.
PMID- 9761442
TI - Preconditioning of the latissimus dorsi muscle in cardiomyoplasty: vascular delay
or chronic electrical stimulation.
AB - OBJECTIVES: In standard single stage cardiomyoplasty (CMP), the latissimus dorsi
muscle (LDM) is not preconditioned prior to surgery. We hypothesized that
latissimus dorsi preconditioning by vascular delay or by chronic electrical
stimulation would result in an improved LV hemodynamic function early (14 days)
after CMP. METHODS: Mongrel dogs had preconditioning of the latissimus dorsi by a
vascular delay procedure followed by CMP 14-18 days later (group I VD). Dogs in
group II underwent 4 weeks of chronic stimulation (CS) of the latissimus dorsi (2
V/30 Hz, six bursts/min) followed by CMP. The latissimus dorsi muscle was fully
stimulated from 48 h after cardiomyoplasty in both groups (2 V/30 Hz, three
bursts/min). Two weeks after myoplasty, injecting 2.0-3.0 x 10(5) 90 microm latex
microspheres in the left main coronary artery induced global cardiac dysfunction.
Hemodynamic function was then evaluated for latissimus dorsi muscle assisted (S)
beats and non-stimulated beats (NS) in each group by measuring peak systolic
aortic pressure (AOP), left ventricular pressure (LVP) and end diastolic pressure
(LVEDP), and by calculating maximum and minimum dP/dt. RESULTS: Dogs with
vascular delay of the latissimus dorsi showed a marked increase for all
hemodynamic indices (AOP: 23.9+/-2.5%, LVP: 23.5+/-2.2%, max dP/dt: 49.4+/-3.3%)
for LDM assisted (S) beats compared to non-stimulated beats (P < 0.001). Animals
with chronic electrical training did not demonstrate a significant increase in
any hemodynamic parameter with LDM stimulation. CONCLUSION: Preconditioning the
LDM may play an important role in providing early cardiac assistance in CMP.
Preconditioning the LDM with vascular delay resulted in improving performance of
the LDM with consistent increases in LV hemodynamics. This was not observed after
preconditioning with chronic electrical stimulation. Vascular delay of the
latissimus dorsi can significantly improve muscle performance in CMP and could
provide hemodynamic assistance early after surgery.
PMID- 9761441
TI - Discrete subaortic stenosis: an acquired heart disease.
AB - OBJECTIVE: To determine the anatomic variables in the left ventricular outflow
tract in patients with subaortic stenosis. METHODS: Between 1982 and 1996, 36
patients were operated on with the 'discrete' form of subaortic stenosis (DSS).
The mean time of follow up was 7.4 years with a range of 4 months-14 years. There
were 25 male and 11 female patients. Mean age at operation was 7.1 years with a
range of 9 months-47 years. RESULTS: At the time of surgery, the mitral valve
apparatus and interventricular septum were found to be rotated 60-90 degrees in a
counterclockwise fashion with anterior displacement into the left ventricular
outflow tract in 30 (83%) patients. Subaortic ridge resection with a deep septal
myectomy was performed in 32 patients and the remaining four patients had
subaortic ridge resection alone. The reoperation free rate at 5 and 10 years were
74+/-9% and 60+/-12%, respectively. Reoperations for recurrent disease were
performed in 10 (27.7%) patients. No operative or late follow up deaths were
encountered. CONCLUSION: We conclude that DSS is an acquired disease due to a pre
existing anatomic alteration in the mitral valve apparatus and interventricular
septum. In addition, recurrence rates are high and physicians should not be
mislead by the benign nomenclature its name implies.
PMID- 9761443
TI - Does bronchial artery revascularization influence results concerning
bronchiolitis obliterans syndrome and/or obliterative bronchiolitis after lung
transplantation?
AB - OBJECTIVE: To study the frequency of histological obliterative bronchiolitis and
clinical bronchiolitis obliterans syndrome after en bloc double lung
transplantation with bronchial artery revascularization and bilateral lung
transplantation without bronchial artery revascularization. METHODS: Primary en
bloc double lung transplantation with bronchial artery revascularization using
the internal mammary artery as conduit was performed in 62 patients. The
frequencies of obliterative bronchiolitis and bronchiolitis obliterans syndrome
have been established from transbronchial biopsies and lung function
measurements. Results have been analyzed in relation to the arteriographic
success of bronchial artery revascularization and have been compared to results
from Stanford University, obtained through personal communications. RESULTS:
Survival after 1, 2, 3, 4 and 5 years was 85, 81, 69, 69, and 69%, respectively.
Fifteen patients developed bronchiolitis obliterans syndrome while seven
developed obliterative bronchiolitis. Survival was superior for patients with
bronchial artery revascularization classified as complete or incomplete bilateral
versus incomplete hemilateral, incomplete poor or failed (P = 0.016, log-rank
test). For patients surviving > or = 3 months post-transplant, the post-operative
baseline FEV1 was lower for patients who later developed bronchiolitis obliterans
syndrome compared to patients who did not (P = 0.007). The development of
bronchiolitis obliterans syndrome and obliterative bronchiolitis were both
correlated to observation time post-transplant but not to the number of
rejections or infections when corrected for observation time. CONCLUSIONS: In a
subgroup of lung transplant patients, a process in the transplanted lungs,
eventually leading to bronchiolitis obliterans syndrome diagnosis, seems to start
in the donor during the transplantation and/or in the early post-operative cause.
A comparison with results after bilateral lung transplantation without bronchial
artery revascularization suggests that good direct bronchial artery
revascularization may postpone the onset of bronchiolitis obliterans syndrome and
obliterative bronchiolitis. The positive trend motivates further use of direct
bronchial artery revascularization in lung transplantation.
PMID- 9761444
TI - Warm ischemic time tolerance after ventilated non-heart-beating lung donation in
piglets.
AB - OBJECTIVE: The availability of lungs for transplantation could be ameliorated
with the use of organs retrieved from ventilated non-heart-beating donors
(VNHBD). The aim of this work is to determine the limit to tolerable in situ warm
ischemia time (WIT) for lung grafts after circulation is stopped. METHODS: Twenty
piglets underwent left lung allotransplantation. Animals were randomly allocated
based on the donor's status before lung harvesting into the following study
groups: Sham (n = 5), Heart-beating donors-non-warm ischemia; I-30 (n = 5), I-60
(n = 5) and I-90 (n = 5), VNHBD-WIT of 30, 60 and 90 min, respectively. Right
pulmonary artery and bronchus were permanently occluded one hour after
transplantation. Assessment of pulmonary function was monitored hourly by
hemodynamic, oxygenation and pulmonary mechanic measurements during a period of 6
h after reperfusion. Lung grafts were weighed pre- and post-transplantation.
RESULTS: Cold ischemic time was similar for all groups, and averaged 80.1+/-2.7
min. Final mean lung weight was significantly greater in VNHBD (92.5+/-3.1 g vs.
Sham values 75.6+/-2.4 g, P < 0.01). After right lung exclusion, hemodynamic
changes consisted of a sustained increase in pulmonary vascular resistance and a
reduction in cardiac output. Lung mechanics also modified, with a rise in airway
resistance and a fall in compliance. CONCLUSIONS: Post-transplantation lung graft
function from VNHBD with up to 90 min of WIT, is equivalent to those achieved by
grafts harvested after heart-beating donation. This method may be a promising
strategy of increasing the pulmonary donor pool.
PMID- 9761445
TI - Aortic valve stenosis causing a left-to-right shunt in persistent left superior
vena cava communicating with the left atrium.
AB - This study demonstrated a rare anomaly of a persistent left superior vena cava
draining into the left atrium in a patient with developing left-to-right shunt
caused by bicuspid aortic stenosis. The venous system, including the coronary
sinus, was otherwise normal. We believe that, in this anatomic situation, a
marked increase in left ventricular impedance caused a moderate left-to-right
shunt from the left atrium into the left innominate vein. At operation, the
aortic valve was replaced with a mechanical prosthesis and the anomalous vein was
ligated. The convalescence was uneventful.
PMID- 9761446
TI - Open surgery for removal of a failing Gianturco stent with reversed sleeve
resection of the right middle and lower lobes.
AB - Although the use of a metallic stent in the treatment of benign tracheobronchial
stenosis has been reported as a useful and safe technique, the incorporation of
wire stents into the airway may be irreversible and is associated with problems.
The authors' experience in a patient with incorrectly positioned metallic stent
in the right main bronchus, which was successfully treated with bronchial sleeve
resection, is presented.
PMID- 9761447
TI - Stent implantation for post-Mustard systemic venous obstruction.
AB - In this paper, we report on the use of stents in the treatment of late-onset post
Mustard systemic venous obstruction in three patients with clinical signs of
obstructive caval syndrome. After unsuccessful balloon dilation, Palmaz-Schatz
stents were implanted at the veno-atrial junction. Further dilation has been
achieved using high-pressure balloons. Vessel diameter increased from 4.4+/-1.8
to 13+/-1.7 mm (P < 0.05) and the trans-stenotic pressure gradient dropped from
8+/-6 to 0 mmHg (P < 0.01), with clinical improvement. After 26+/-4 months of non
invasive follow-up, no signs of recurrent stenosis were observed. Stent
implantation is effective in the treatment of systemic venous obstruction after
Mustard operation.
PMID- 9761448
TI - A multivesicular cardiac hydatid cyst with hepatic involvement.
AB - Cardiac hydatid cyst is an uncommon lesion, mostly caused by Echinococcus
granulosus. Occurrence of the disease in man appears to be limited geographically
to areas where close and continuous contact exists between domesticated
carnivores such as dogs and ungulates such as cattle and sheep. Generally cardiac
hydatid cysts are univesicular. Here we report our clinical and surgical
experience of treatment in a case of a multivesicular cardiac hydatid cyst with
hepatic involvement.
PMID- 9761449
TI - Surgical approach for cardiac surgery in a patient with tracheostoma.
AB - The thoracic approach for cardiac surgery in a patient with a tracheostoma can
result in difficult problems, such as mediastinitis, stoma necrosis or inadequate
operative exposure. We present a distinct approach consisting of an incision at
the second intercostal space, transverse sternum transection and longitudinal
median sternotomy to the xiphoid process, performed for coronary artery bypass
grafting and aortic valve replacement, in a patient with previous tracheotomy.
This approach permitted adequate surgical exposure for cardiopulmonary bypass,
aortic valve replacement and coronary revascularization procedures.
PMID- 9761450
TI - Images in cardio-thoracic surgery. Giant benign localized fibrous tumor of the
pleura.
PMID- 9761451
TI - A case of extreme negative intrathoracic pressure.
PMID- 9761452
TI - The glutamate transporter, GLT-1, is expressed in cultured hippocampal neurons.
AB - There are multiple subtypes of Na+-dependent glutamate transporters. Several
studies suggest that EAAC1 and EAAT4 are expressed in neurons, while GLT-1 and
GLAST expression is thought to be restricted to glia. In the present study,
expression of GLT-1 and EAAC1 was examined in cultured rat hippocampal neurons
using single cell mRNA amplification and immunocytochemistry with subtype
specific antibodies. GLT-1 and EAAC1 mRNAs were observed in all neurons examined.
Neuronal phenotype was confirmed in these cells by expression of neurofilament
(NF-L) mRNA and absence of glial fibrillary acidic protein (GFAP) mRNA. EAAC1
immunoreactivity was observed in essentially all cells which expressed neuron
specific enolase (NSE) and GLT-1 immunoreactivity was detected in the majority
(approximately 90%) of NSE-positive cells. Consistent with the glial expression
of GLT-1, GLT-1 immunoreactivity was also observed in NSE-negative cells. These
studies provide evidence that GLT-1 expression is not intrinsically restricted to
glial cells, but can occur in neurons under certain circumstances.
PMID- 9761453
TI - Interferon beta-1b inhibits reactive oxygen species production in peripheral
blood monocytes of patients with relapsing-remitting multiple sclerosis.
AB - We studied the rate of reactive oxygen species (ROS) production by monocytes 'ex
vivo' in a cohort of healthy individuals, in a group of MS patients undergoing
treatment with interferon beta-1b and another group of MS patients who refused
treatment with interferon beta-1b. The rate of ROS production in healthy
individuals was slightly lower than in non-treated MS patients. The lower rate of
ROS production was obtained in monocytes of MS patients treated with interferon
beta-1b. These results indicate that the treatment of relapsing-remitting MS
patients with interferon beta-1b rendered the NADPH oxidase of the monocytes less
sensitive to trigger reactive oxygen species (ROS).
PMID- 9761454
TI - A new procedure for determining ganglioside GD3 a potential glial cell activation
marker in cerebrospinal fluid.
AB - Increased amounts of ganglioside GD3 [II3 (NeuAc)2-LacCer], associated with
reactive gliosis, have been documented in a variety of neurodegenerative
disorders. GD3 expression has also been reported in microglial cells, not only
during development but also in reactive states, where the glial activation is
considered to be part of the repair process. It is important to find markers in
cerebrospinal fluid that will enable us to identify damage and register changes
in pathological processes within the brain. A sensitive and practically
applicable method for determination of GD3 ganglioside in cerebrospinal fluid has
been developed. The procedure, which includes extraction, purification on silica
gel and thin-layer enzyme-linked immunostaining, also allows determination of
sulphatide, a marker of demyelinating processes, in the same portion of CSF. The
method has been applied to CSF samples from 101 normal individuals aged 2-83
years. The GD3 concentration was found to be significantly correlated to age and
reflecting the concentrations within the brain. GD3 ganglioside analysis by means
of this method might be useful for studying glial changes during brain maturation
as well as in brain disorders.
PMID- 9761456
TI - A2a adenosine receptors: guanine nucleotide derivative regulation in porcine
striatal membranes and digitonin soluble fraction.
AB - We report the characterization of A2a adenosine receptors (A2aARs) in porcine
striatal membranes and their solubilization (25%) by the detergent digitonin.
After solubilization, the drug specificity and equilibrium [3H]CGS-21680 ([3H]2
(4-(2-carboxyethyl)phenylethylamino)-5'-N-ethyl-carboxamido -adenosine) binding
parameters were virtually identical to those obtained in intact membranes,
indicating a conservation of the binding site after the removal of receptors from
their lipid environment. Gel filtration on a calibrated Superdex 200 HR column
revealed a main [3H]CGS-21680 binding peak with an apparent molecular weight of
171,000+/-9000 Da. In membranes, Scatchard analysis of saturation data carried
out in a wide range of radioligand concentration (1-100 nM) resulted in a
biphasic curve and, in accordance with the two binding sites model, yielded a Kd1
= 7.4+/-0.5 and Kd2 = 53.1+/-3.6 nM, a Bmax1 = 186+/-15 fmol/mg protein and a
Bmax2 = 285+/-20 fmol/mg protein, respectively. In the presence of guanosine-5'-O
(3-thiotriphosphate) (GTPgamma[S]) a shift from two affinity states to a single
one was evidenced (Kd = 28.5+/-5.9 nM) and a Bmax value of 504+/-10 fmol/mg
protein found. In the soluble extract, only one high-affinity state was detected
(Kd = 19.3+/-1.1 nM and Bmax = 285+/-20 fmol/mg protein) and, in the presence of
GTPgamma[S]), a two site model likewise provided a significantly (P < 0.01)
better fit (Kd1 = 13.9+/-1.2 nM and Kd2 = 72.1+/-6.9 nM, Bmax1 = 125+/-10 fmol/mg
protein and Bmax2 = 375+/-19 fmol/mg protein, respectively). These results
suggest a close relation between the receptor and G protein solubilized as a
functional unit and open the way to its purification.
PMID- 9761455
TI - Intracerebroventricular administration of quinolinic acid induces a selective
decrease of inositol(1,4,5)-trisphosphate receptor in rat brain.
AB - [3H]inositol(1,4,5)-trisphosphate (IP3) binding studies have shown decreased
[3H]IP3 binding to brain tissue in several neurodegenerative diseases, including
Alzheimer's and Huntington's diseases. In addition, previous results obtained
from brains of Alzheimer patients indicated a reduction of IP3-receptor protein
correlated to neuronal loss. The neurotoxic effect of the glutamate receptor
agonist quinolinic acid (QUIN) was therefore examined with respect to the level
of IP3-receptor immunoreactivity in rat brain. Neuronal lesions were estimated
with antibodies to marker proteins for striatal medium-sized spiny neurons
(dopamine- and cyclic AMP-regulated phosphoprotein, Mr 32,000; DARPP-32),
synaptic vesicles (synaptophysin), mitochondria (phosphate-activated glutaminase;
PAG) and glial cells (glial fibrillary acidic protein; GFAP). Injection of QUIN
into rat neostriatum induced a massive loss of striatal medium-sized spiny
neurons, and led to a comparable loss of IP3-receptor and PAG immunoreactivity,
suggesting a neuronal localisation of both these proteins. In an effort to induce
less pronounced excitotoxic damage, intracerebroventricular infusion of QUIN was
performed. Following this lesion, the neostriatum showed a negligible loss of
DARPP-32 immunoreactivity (-11+/-5%), but contained only 43+/-3% of IP3-receptor
immunoreactivity levels compared to controls. In the hippocampus, cerebellum and
entorhinal cortex, the IP3-receptor loss was less pronounced. The decrease in the
level of IP3-receptor immunoreactivity appears to be selective with respect to
the other proteins studied, and the IP3-receptor thus shows extreme sensitivity
to QUIN neurotoxicity in the neostriatum.
PMID- 9761457
TI - Acetylcholinesterase at high catalytic efficiency and substrate specificity in
the optic lobe of Eledone moschata (Cephalopoda: Octopoda): biochemical
characterization and histochemical localization.
AB - In the optic lobe of the cephalopod mollusc Eledone moschata, two
acetylcholinesterase forms I and II were detected, both showing a marked active
site specificity with differently sized substrates. Catalytic efficiency
(kcat/Km) of the prevailing form II is similar to that of acetylcholinesterases
from vertebrate nervous system. Enzyme forms I and II were co-purified from a
high-salt-Triton X-100 soluble extract of optic lobe by consecutive affinity
chromatographies on procainamide- and concanavalin A-Sepharose columns and then
separately obtained by preparative density gradient centrifugation. According to
gel-filtration chromatography, sedimentation analysis and SDS-PAGE, the major
form II is an amphiphilic globular dimer (135-136 kDa, 6.3-7.4 S) of monomers (66
kDa) S-S linked between terminal segments. Phosphatidylinositol anchors give cell
membrane insertion, self-aggregation and detergent (Triton X-100, Brij 97)
interaction. Form I, characterized only in part owing to its small amount, showed
molecular size (129 kDa) and sedimentation coefficient (7.5 S) similar to those
of form II; it is likely to be attached to the cell membrane by electrostatic
interactions. Both forms behaved similarly with various inhibitors and underwent
excess-substrate inhibition. The results obtained suggest a common origin of both
form I and II from a single gene. The former could be a degradation product of
the prevailing one (II), which is likely to be functional in cholinergic
synapses.
PMID- 9761458
TI - Mouse interleukin-6 stimulates the HPA axis and increases brain tryptophan and
serotonin metabolism.
AB - Neuroendocrine and neurochemical responses were studied following administration
of recombinant mouse IL-6 (mIL-6) to mice. Intravenous (iv) or intraperitoneal
(ip) injection of mIL-6 caused a rapid and short-lived activation of the
hypothalamo-pituitary-adrenocortical (HPA) axis, as indicated by increases in
plasma ACTH and corticosterone, with peak responses around 30-60 min. These
responses contrast with those to ip mIL-1beta which is substantially more potent
and induces a greater response which does not peak until about 2 h following ip
administration. Unlike IL-1 and lipopolysaccharide (LPS), IL-6 had no detectable
effect on norepinephrine metabolism. However, tryptophan concentrations were
elevated in most brain regions studied 1-2 h following iv mIL-6, and 2 h
following ip mIL-6, significantly later than the peak HPA response. 5
hydroxyindoleacetic acid (5-HIAA) and the ratio of 5-HIAA to serotonin (5-HT)
were elevated at around the same time in the brain stem, and occasionally in
other brain regions. These responses were observed at doses of mIL-6 as low as
0.25 microg, and near maximal effects were achieved by 0.5 microg. Recombinant
human IL-6 elicited similar responses, but was significantly less potent. Heat
treated mIL-6 elicited none of the responses. Serum amyloid A protein (SAA)
concentrations were not elevated until 4 h after iv or ip mIL-6 administration,
suggesting that the neuroendocrine and neurochemical changes were not secondary
to an acute phase protein response. Intracerebroventricular injection of mIL-6
also elevated tryptophan and 5-HIAA in the hypothalamus and brain stem.
Pretreatment of mice with the cyclooxygenase inhibitor, indomethacin, or the
nitric oxide synthase inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME)
did not attenuate the mIL-6 induced neuroendocrine or neurochemical responses.
However, the ganglionic blocking drug, chlorisondamine, prevented the increases
in tryptophan and 5-HIAA:5-HT ratios. IL-6 may contribute to the HPA and
indoleaminergic responses to LPS and IL-1. It is possible that the increases of
tryptophan and serotonin metabolism may contribute to some of the biological
effects of IL-6.
PMID- 9761459
TI - Complex polyamine effects on [3H]MDL 105,519 binding to the NMDA receptor glycine
site.
AB - Several studies have suggested that polyamines modulate the interaction of
glycine with the NMDA receptor. We have further investigated the effects of
polyamines using the NMDA receptor glycine site antagonist [(E)-3-(2-phenyl-2
carboxyethenyl)-4,6-dichloro-1H-indole-2-carbox ylic acid] ([3H]MDL 105,519).
[3H]MDL 105,519 binding assays were performed using well washed membranes
prepared from frozen rat brains. The polyamines spermine and spermidine increased
the fraction of non-specific binding (determined by the addition of 1 mM glycine)
in the [3H]MDL 105,519 binding assay from 40-60% when spermine or spermidine
concentration was increased from 1 to 100 microM. Polyamine agonists spermine,
spermidine and 1,5-(diethylamino)piperidine (30 microM) did not have a
significant effect on displacement of [3H]MDL 105,519 binding by glycine or
glycine site antagonists. Similarly, the polyamine antagonist arcaine did not
have a significant effect on displacement of [3H]MDL 105,519 binding by glycine
or glycine site antagonists. However, spermidine significantly depressed the
potency of MDL 105,519 in displacing [3H]dizocilpine binding. These data suggest
that [3H]MDL 105,519 may preferentially bind to a polyamine insensitive form of
the NMDA receptor.
PMID- 9761461
TI - Diverse effects of mild and potent goitrogens on blood-brain barrier nutrient
transport.
AB - Populations living in goitre endemic areas consume foods rich in a variety of
goitrogens of different potencies and some are severely hypothyroid. Recently we
observed in Wistar/NIN rats that chronic feeding of KSCN to dams produced only a
moderate hypothyroidism and decreased the transport of 2-deoxy-D-glucose (2-DG)
across the blood-brain barrier (BBB) in the offspring. The present studies were
conducted to assess whether severe hypothyroidism would have greater effect on
BBB nutrient transport. It has now been observed that weaning the pups of KSCN
fed dams on to KSCN diet for four weeks had no further effect either on their
thyroid status or the BBB 2-DG transport. However, feeding KSCN to rats through
two generations produced somewhat severe hypothyroidism in F2 pups than that in
F1 pups. Interestingly, unlike in F1 pups, the BBB transport of all the three
nutrients tested (2-DG, Leu and Tyr) was significantly decreased in F2 pups,
albeit to a small extent (10-15%). On the other hand the potent goitrogen: methyl
mercaptoimidazole (MMI) even on short term feeding to pregnant dams produced very
severe hypothyroidism in the offspring [Serum T4:0.55+/-0.09 microg/dl vs 4.96+/
0.85 in controls]. Surprisingly, the BBB transport of 2-DG, Leu, Tyr and also
sucrose, the background marker, was significantly increased in these pups (20
30%). The diverse effects of goitrogen-induced moderate and severe hypothyroidism
observed here on the BBB nutrient transport probably suggest different mechanisms
for iodine deficiency disorders of different aetiologies and hence the need for
discrete approaches for their management.
PMID- 9761460
TI - Comparison of the effects of hydrogen peroxide, 4-hydroxy-2-nonenal and beta
amyloid (25-35) upon calcium signalling.
AB - The neurotoxic beta-amyloid (Abeta) peptide fragment Abeta(25-35) has been
suggested to exert its deleterious effects on cells via production of hydrogen
peroxide. In human platelets and in the presence of DMSO to prevent production of
hydroxyl radicals from hydrogen peroxide, both Abeta(25-35) and hydrogen peroxide
were found to increase intracellular calcium levels. Hydrogen peroxide in
addition reduced the calcium response to thrombin, whereas this was not seen with
Abeta(25-35). A similar pattern of effects to those seen with hydrogen peroxide
were also seen with the neurotoxic aldehyde lipid peroxidation product 4-hydroxy
2-nonenal (HNE). The initial increase in calcium produced by hydrogen peroxide
was not affected by EGTA, but was partially prevented by dithiothreitol. The
calcium response to Abeta(25-35) [which was also seen with Abeta(1-40) and
Abeta(1-42) but not with the inactive peptide Abeta(40-1)] consisted of an EGTA
sensitive and an EGTA-resistant component, of which the latter was also sensitive
to DTT. Hydrogen peroxide increased basal phosphoinositide breakdown in rat brain
miniprisms and decreased the responses to noradrenaline, carbachol and veratrine.
The specific binding of [3H]inositol-1,4,5-trisphosphate ([3H]Ins(1,4,5)P3) to
its receptor recognition site in human platelet membranes was increased by
Abeta(25-35) but remained unchanged following hydrogen peroxide treatment. It is
concluded that under conditions where production of hydroxyl radicals from
hydrogen peroxide is blocked, hydrogen peroxide and Abeta(25-35) produce their
effects on calcium by affecting the mobilisation of intracellular calcium. The
qualitative differences in the calcium responses of these two agents can be
explained (a) by an additional effect of Abeta(25-35) upon calcium entry and (b)
by differences in their effects upon the Ins(1,4,5)P3 receptor.
PMID- 9761462
TI - Expression of G-protein subtypes in cultured cerebral endothelial cells.
AB - This paper describes Western-blotting evidence for the presence of various
guanine nucleotide binding proteins, G-proteins in cultured rat cerebral
endothelial cells (CECs) and two immortalized cerebral endothelial cell lines,
RBE4 and GP8. By using specific antibodies raised against known sequences of
appropriate G-protein types that were previously characterized, we demonstrated
the presence of Gsalpha, Gi2alpha, Gi3alpha, Gq/11alpha, Goalpha and Gbeta in
cell lysates of primary cultures of CECs, and plasma membranes of RBE4 and GP8
cells. The appearance of Goalpha proteins in CECs might be of special importance,
since they were not detected in peripheral endothelial cells in previous studies.
Isoproterenol and bradykinin displayed significant, dose-dependent stimulation of
[35S]GTPgammaS binding above basal values. This assay, reflecting the GDP-GTP
exchange reaction on Galpha-subunits by receptor agonists, suggested that there
were functional, G-protein coupled beta-adrenergic and bradykinin receptors in
these systems. No significant stimulation of [35S]GTP7gammaS binding was noted
with serotonin under our experimental conditions. Since stimulation of
[35S]GTPgammaS binding by isoproterenol and bradykinin was additive, it was
concluded that different Galpha proteins were activated by these two ligands. In
analogy to other systems, activation of Gs is most likely by isoproterenol, while
Gi and/or Gq/11 proteins might be activated by bradykinin receptors. The possible
significance of the receptors and G-proteins detected is being discussed in the
functioning of cerebral endothelium, and thus the blood-brain barrier.
PMID- 9761464
TI - Immunohistochemical localization of taurine in the retina of developing and adult
human and adult monkey.
AB - The localization of taurine in the retina of fetal (12-25 weeks of gestation),
postnatal (five-month-old infant) and adult human (35- and 65-year-old) was
examined by immunohistochemistry. Additionally, retinas of fresh adult monkey,
which served as positive controls, were employed. No immunoreactivity was found
in the fetal retinas from 12-15 weeks of gestation. At 1617 weeks of gestation,
the ganglion cells and some of their axons were conspicuously labelled for
taurine. At 18-19 weeks, Muller glial endfeet, the inner plexiform layer, some
amacrine and putative horizontal cells and photoreceptors showed moderate
immunoreactivity. With further development at 20-21 and 24-25 weeks of gestation,
the immunoreactivity was prominent in Muller cell endfeet, some bipolar cells and
in horizontal cells that were aligned in a row in the inner nuclear layer, close
to the fovea. At both fetal stages, the photoreceptors and horizontal cells
showed strong immunoreactivity. In the postnatal infant retina, taurine
immunoreactivity was present in some amacrine cells and photoreceptor inner
segments and nuclei, but not in ganglion and horizontal cells, which was also the
pattern noted in the adult monkey and human retinas. With development, a shift in
the intensity of taurine immunoreactivity was noted towards the outer retina. The
expression of taurine immunoreactivity in most fetal retinal neurons implies a
role for this amino acid in the normal development as well as maturation of human
retina.
PMID- 9761463
TI - Alterations of striatal cholinergic receptors after lesioning of the substantia
nigra.
AB - Dopamine deficiency syndrome is known to cause cholinergic hyperactivity.
Therefore, it was hypothesized that the said phenomenon may be due to enhanced
cholinergic receptor functions. In the present study we examined the changes in
striatal dopaminergic and cholinergic receptors in unilateral substantia nigra
lesioned rats that showed vigorous ipsilateral rotation (total turns > 300) in
response to apomorphine (1 mg kg(-1) ip). [3H] Spiperone ([3H]-SP) and [3H]
quinuclidinyl benzilate ([3H]-QNB) bindings were performed in the striata of the
lesioned animals. There was no significant difference in the dissociation
equilibrium constant values (Kd) between the lesioned and non-lesioned sides.
However, a significant difference in the maximum receptor density (Bmax) of both
[3H]-SP and [3H]-QNB bindings was observed between the lesioned and non-lesioned
sides. The Bmax of [3H]-SP binding was significantly decreased on the lesioned
side, whereas the Bmax of the [3H]-QNB binding was significantly increased. These
results support the hypothesis that deficiencies of the dopaminergic system cause
overactivity of the cholinergic system in the striatum.
PMID- 9761465
TI - Increases in levels of brain-derived neurotrophic factor mRNA and its promoters
after transient forebrain ischemia in the rat brain.
AB - Expression of brain-derived neurotrophic factor (BDNF) may play a role in the
mechanism of neuronal cell death after cerebral ischemia. We investigated the
changes in levels of mRNAs encoding BDNF and its promoters in the rat brain after
transient forebrain ischemia. Transient forebrain ischemia was induced by
occlusion of bilateral common carotid arteries and systemic hypotension for 8
min. The alterations in BDNF gene expression in the hippocampus and in the
cerebral cortex were examined by in situ hybridization using a mouse BDNF cDNA
probe and cDNA probes including exon-specific promoters. BDNF transcripts were
rapidly enhanced after the ischemic insult, both in the hippocampus and the
cerebral cortex. NBQX suppressed the enhanced gene expression of BDNF markedly in
the dentate gyrus (DG). In contrast, MK-801 had little effect on BDNF expression.
In the piriform cortex, MK-801 or NBQX reduced the expression only moderately.
After the ischemic insult, promoter specific BDNF 5'-exon I and exon III were
increased remarkably in the DG. The increase in exon I in DG was suppressed
partially by MK-801 and NBQX, while the increase in exon III in CA3 was
suppressed by MK-801 but that in DG was not suppressed by either antagonist. In
the piriform cortex, exon III was increased remarkably and this increase was not
influenced by either agonist. These results suggest that the gene expression of
BDNF was enhanced by transient ischemia both in the hippocampus and the cerebral
cortex and that the cerebral ischemia stimulated at least two different promoter-
and neuron type-specific pathways regulating expression of the BDNF gene mediated
by glutamate receptors of non-NMDA type and NMDA type.
PMID- 9761466
TI - Class-directed structure determination: foundation for a protein structure
initiative.
AB - The recent sequencing of many complete genomes, combined with the development of
methods that allow rapid structure determination for many proteins, has changed
the way in which protein structure determinations can be approached. One-by-one
determinations of individual protein structures will soon be augmented by class
directed structure analyses in which a group of proteins is targeted and
structures of representative members are determined and used to represent the
entire group. Such a shift in approach would be the foundation for a broad
protein structure initiative targeting classes of proteins important for
biotechnology and for a fundamental understanding of protein function.
PMID- 9761467
TI - Kinetic epitope mapping of the chicken lysozyme.HyHEL-10 Fab complex: delineation
of docking trajectories.
AB - The rate constants, k(on), for the formation of hen (chicken) lysozyme (HEWL).
Fab-10 complexes have been determined for wild-type (WT) and epitope-mutated
lysozymes by a homogeneous solution method based on the 95% reduced enzymatic
activity of the complex. The values fall within a narrow 10-fold range [(0.18 to
1.92) x 10(6) M(-1)s(-l)]. The affinity constants, K(D), cover a broader, 440
fold, range from 0.075 to 33 nM. Values of K(D) as high as 7 microM were obtained
for the complexes prepared from some mutations at HEWL positions 96 and 97, but
the associated kinetic constants could not be determined. The values of k(on) are
negatively correlated with side-chain volume at position 101HEWL, but are
essentially independent of this parameter for position 21HEWL substitutions. The
multiple mutations made at positions 21HEWL and 101HEWL provide sufficient
experimental data on complex formation to evaluate phi values [phi =
(deltadeltaGon)/(deltadeltaG(D))] at these two positions to begin to define
trajectories for protein-protein association. The data, when interpreted within
the concept of a two-step association sequence embracing a metastable encounter
complex intermediate, argue that the rate determining step at position 21HEWL
(phiavg = 0.2) is encounter complex formation, but the larger phi(avg) value of
0.36 experienced for most position 101HEWL mutations indicates a larger
contribution from the post-encounter annealing process at this site for these
replacements.
PMID- 9761468
TI - Quantitative evaluation of the chicken lysozyme epitope in the HyHEL-10 Fab
complex: free energies and kinetics.
AB - The hen (chicken) egg-white lysozyme (HEWL) epitope for the monoclonal antibody
HyHEL-10 Fab (Fab-10) was investigated by alanine scan mutagenesis. The
association rate constants (k(on)) for the HEWL Fab-10 complexes were obtained
from the homogenous solution method described in the preceding paper (Taylor et
al., 1998). A new method for determining the dissociation rate constant (k(off))
for the complex, by trapping nascent free antibody with an inactive HEWL mutant
is described. The values of k(on) fall within a factor of 2 of the wild-type (WT)
HEWL value (1.43+/-0.13 X 10(6)M(-1)s(-1)), while the increases in k(off)more
nearly reflect the total change in free energies of the complex (deltadeltaG(D)).
The dissociation constants (K(D)) were measured directly in those cases where
satisfactory kinetic data could not be obtained. The Y20A, K96A, and K97A
HEWL.Fab-10 complexes are destabilized by more than 4 kcal/mol compared to the WT
complex. The R21A, L75A, and D101A antibody complexes are moderately destabilized
(0.7 < deltadeltaG(D)< or = 1.0 kcal/mol). Additional mutations of the "hotspot"
residues (Tyr20, Lys96, Lys97) were constructed to probe, more precisely, the
nature of their contributions to complex formation. The results show that the
entire hydrocarbon side chains of Tyr20 and Lys97, and only the epsilon-amino
group of Lys96, contribute to the stability of the complex. The value of
deltadeltaG(D) for the R21A mutant complex is a distinct outlier in the Arg21
replacement series demonstrating the importance of supplementing alanine scan
mutagenesis with additional mutations.
PMID- 9761469
TI - Conversion of a beta-strand to an alpha-helix induced by a single-site mutation
observed in the crystal structure of Fis mutant Pro26Ala.
AB - The conversion from an alpha-helix to a beta-strand has received extensive
attention since this structural change may induce many amyloidogenic proteins to
self-assemble into fibrils and cause fatal diseases. Here we report the
conversion of a peptide segment from a beta-strand to an alpha-helix by a single
site mutation as observed in the crystal structure of Fis mutant Pro26Ala
determined at 2.0 A resolution. Pro26 in Fis occurs at the point where a flexible
extended beta-hairpin arm leaves the core structure. Thus it can be classified as
a "hinge proline" located at the C-terminal end of the beta2-strand and the N
terminal cap of the A alpha-helix. The replacement of Pro26 to alanine extends
the A alpha-helix for two additional turns in one of the dimeric subunits;
therefore, the structure of the peptide from residues 22 to 26 is converted from
a beta-strand to an alpha-helix. This result confirms the structural importance
of the proline residue located at the hinge region and may explain the mutant's
reduced ability to activate Hin-catalyzed DNA inversion. The peptide (residues 20
to 26) in the second monomer subunit presumably retains its beta-strand
conformation in the crystal; therefore, this peptide shows a "chameleon-like"
character since it can adopt either an alpha-helix or a beta-strand structure in
different environments. The structure of Pro26Ala provides an additional example
where not only the protein sequence, but also non-local interactions determine
the secondary structure of proteins.
PMID- 9761470
TI - Anatomy of protein pockets and cavities: measurement of binding site geometry and
implications for ligand design.
AB - Identification and size characterization of surface pockets and occluded cavities
are initial steps in protein structure-based ligand design. A new program, CAST,
for automatically locating and measuring protein pockets and cavities, is based
on precise computational geometry methods, including alpha shape and discrete
flow theory. CAST identifies and measures pockets and pocket mouth openings, as
well as cavities. The program specifies the atoms lining pockets, pocket
openings, and buried cavities; the volume and area of pockets and cavities; and
the area and circumference of mouth openings. CAST analysis of over 100 proteins
has been carried out; proteins examined include a set of 51 monomeric enzyme
ligand structures, several elastase-inhibitor complexes, the FK506 binding
protein, 30 HIV-1 protease-inhibitor complexes, and a number of small and large
protein inhibitors. Medium-sized globular proteins typically have 10-20
pockets/cavities. Most often, binding sites are pockets with 1-2 mouth openings;
much less frequently they are cavities. Ligand binding pockets vary widely in
size, most within the range 10(2)-10(3)A3. Statistical analysis reveals that the
number of pockets and cavities is correlated with protein size, but there is no
correlation between the size of the protein and the size of binding sites. Most
frequently, the largest pocket/cavity is the active site, but there are a number
of instructive exceptions. Ligand volume and binding site volume are somewhat
correlated when binding site volume is < or =700 A3, but the ligand seldom
occupies the entire site. Auxiliary pockets near the active site have been
suggested as additional binding surface for designed ligands (Mattos C et al.,
1994, Nat Struct Biol 1:55-58). Analysis of elastase-inhibitor complexes suggests
that CAST can identify ancillary pockets suitable for recruitment in ligand
design strategies. Analysis of the FK506 binding protein, and of compounds
developed in SAR by NMR (Shuker SB et al., 1996, Science 274:1531-1534),
indicates that CAST pocket computation may provide a priori identification of
target proteins for linked-fragment design. CAST analysis of 30 HIV-1 protease
inhibitor complexes shows that the flexible active site pocket can vary over a
range of 853-1,566 A3, and that there are two pockets near or adjoining the
active site that may be recruited for ligand design.
PMID- 9761471
TI - Effects of salt bridges on protein structure and design.
AB - Theoretical calculations (Hendsch ZS & Tidor B, 1994, Protein Sci 3:211-226) and
experiments (Waldburger CD et al., 1995, Nat Struct Biol 2:122-128; Wimley WC et
al., 1996, Proc Natl Acad Sci USA 93:2985-2990) suggest that hydrophobic
interactions are more stabilizing than salt bridges in protein folding. The lack
of apparent stability benefit for many salt bridges requires an alternative
explanation for their occurrence within proteins. To examine the effect of salt
bridges on protein structure and stability in more detail, we have developed an
energy function for simple cubic lattice polymers based on continuum
electrostatic calculations of a representative selection of salt bridges found in
known protein crystal structures. There are only three types of residues in the
model, with charges of -1, 0, or + 1. We have exhaustively enumerated
conformational space and significant regions of sequence space for three
dimensional cubic lattice polymers of length 16. The results demonstrate that,
while the more highly charged sequences are less stable, the loss of stability is
accompanied by a substantial reduction in the degeneracy of the lowest-energy
state. Moreover, the reduction in degeneracy is greater due to charges that pair
than for lone charges that remain relatively exposed to solvent. We have also
explored and illustrated the use of ion-pairing strategies for rational
structural design using model lattice studies.
PMID- 9761472
TI - Uclacyanins, stellacyanins, and plantacyanins are distinct subfamilies of
phytocyanins: plant-specific mononuclear blue copper proteins.
AB - The cDNAs encoding plantacyanin from spinach were isolated and characterized. In
addition, four new cDNA sequences from Arabidopsis ESTs were identified that
encode polypeptides resembling phytocyanins, plant-specific proteins constituting
a distinct family of mononuclear blue copper proteins. One of them encodes
plantacyanin from Arabidopsis, while three others, designated as uclacyanin 1, 2,
and 3, encode protein precursors that are closely related to precursors of
stellacyanins and a blue copper protein from pea pods. Comparative analyses with
known phytocyanins allow further classification of these proteins into three
distinct subfamilies designated as uclacyanins, stellacyanins, and plantacyanins.
This specification is based on (1) their spectroscopic properties, (2) their
glycosylation state, (3) the domain organization of their precursors, and (4)
their copper-binding amino acids. The recombinant copper binding domain of
Arabidopsis uclacyanin 1 was expressed, purified, and shown to bind a copper atom
in a fashion known as "blue" or type 1. The mutant of cucumber stellacyanin in
which the glutamine axial ligand was substituted by a methionine (Q99M) was
purified and shown to possess spectroscopic properties similar to uclacyanin 1
rather than to plantacyanins. Its redox potential was determined by cyclic
voltammetry to be +420 mV, a value that is significantly higher than that
determined for the wild-type protein (+260 mV). The available structural data
suggest that stellacyanins (and possibly other phytocyanins) might not be
diffusible electron-transfer proteins participating in long-range electron
transfer processes. Conceivably, they are involved in redox reactions occurring
during primary defense responses in plants and/or in lignin formation.
PMID- 9761473
TI - Electrostatic interactions in the acid denaturation of alpha-lactalbumin
determined by NMR.
AB - alpha-Lactalbumin (alpha-LA) undergoes a pH-dependent unfolding from the native
state to a partially unfolded state (the molten globule state). To understand the
role of electrostatic interactions in protein denaturation, NMR and CD pH
titration experiments are performed on guinea pig alpha-LA. Variation of pH over
the range of 7.0 to 2.0 simultaneously leads to the acid denaturation of the
protein and the titration of individual ionizable groups. The pH titrations are
interpreted in the context of these coupled events, and indicate that acid
denaturation in alpha-LA is a cooperative event that is triggered by the
protonation of two ionizable residues. Our NMR results suggest that the critical
electrostatic interactions that contribute to the denaturation of alpha-LA are
concentrated in the calcium binding region of the protein.
PMID- 9761474
TI - The de novo design of a rubredoxin-like Fe site.
AB - A redox center similar to that of rubredoxin was designed into the 56 amino acid
immunoglobulin binding B1 domain of Streptococcals protein G. The redox center in
rubredoxin contains an iron ion tetrahedrally coordinated by four cysteine
residues, [Fe(S-Cys)4](-1),(-2). The design criteria for the target site included
taking backbone movements into account, tetrahedral metal-binding, and
maintaining the structure and stability of the wild-type protein. The optical
absorption spectrum of the Co(II) complex of the metal-binding variant is
characteristic of tetrahedral chelation by four cysteine residues. Circular
dichroism and nuclear magnetic resonance measurements reveal that the metal-free
and Cd(II)-bound forms of the variant are folded correctly and are stable. The
Fe(III) complex of the metal-binding mutant reproduces the optical and the
electron paramagnetic resonance spectra of oxidized rubredoxin. This demonstrates
that the engineered protein chelates Fe(III) in a tetrahedral array, and the
resulting center is similar to that of oxidized rubredoxin.
PMID- 9761475
TI - Structural/functional properties of the Glu1-HSer57 N-terminal fragment of human
plasminogen: conformational characterization and interaction with kringle
domains.
AB - The Glu1-Val79 N-terminal peptide (NTP) domain of human plasminogen (Pgn) is
followed by a tandem array of five kringle (K) structures of approximately 9 kDa
each. K1, K2, K4, and K5 contain each a lysine-binding site (LBS). Pgn was
cleaved with CNBr and the Glul-HSer57 N-terminal fragment (CB-NTP) isolated. In
addition, the Ile27-Ile56 peptide (L-NTP) that spans the doubly S-S bridged loop
segment of NTP was synthesized. Pgn kringles were generated either by proteolytic
fragmentation of Pgn (K4, K5) or via recombinant gene expression (rK1, rK2, and
rK3). Interactions of CB-NTP with each of the Pgn kringles were monitored by 1H
NMR at 500 MHz and values for the equilibrium association constants (Ka)
determined: rK1, Ka approximately 4.6 mM(-1); rK2, Ka approximately 3.3 mM(-1);
K4, Ka approximately 6.2 mM-'; K5, K, 2.3 mM(-1). Thus, the lysine-binding
kringles interact with CB-NTP more strongly than with Nalpha-acetyl-L-lysine
methyl ester (Ka < 0.6 mM(-l), which reveals specificity for the NTP. In
contrast, CB-NTP does not measurably interact with rK3. which is devoid of a LBS.
CB-NTP and L-NTP 1H-NMR spectra were assigned and interproton distances estimated
from 1H-1H Overhauser (NOESY) experiments. Structures of L-NTP and the Glul-Ile27
segment of CB-NTP were computed via restrained dynamic simulated annealing/energy
minimization (SA/EM) protocols. Conformational models of CB-NTP were generated by
joining the two (sub)structures followed by a round of constrained SA/EM. Helical
turns are indicated for segments 6-9, 12-16, 28-30, and 45-48. Within the Cys34
Cys42 loop of L-NTP, the structure of the Glu-Glu-Asp-Glu-Glu39 segment appears
to be relatively less defined, as is the case for the stretch containing Lys5O
within the Cys42-Cys54 segment, consistent with the latter possibly interacting
with kringle domains in intact Glul-Pgn. Overall, the CB-NTP and L-NTP fragments
are of low regular secondary structure content-as indicated by UV-CD spectra- and
exhibit fast amide 1H-2H exchange in 2H2O, suggestive of high flexibility.
PMID- 9761476
TI - Lysine-50 is a likely site for anchoring the plasminogen N-terminal peptide to
lysine-binding kringles.
AB - Interactions between the kringle 4 (K4) domain of human plasminogen (Pgn) and
segments of the N-terminal Glu1-Lys77 peptide (NTP) have been investigated via 1H
NMR at 500 MHz. NTP peptide stretches devoid of Lys residues but carrying an
internal Arg residue show negligible affinity toward K4 (equilibrium association
constant Ka < 0.05 mM(-1)). In contrast, while most fragments containing an
internal Lys residue exhibit affinities comparable to that shown by the blocked
Lys derivative Nalpha-acetyl-L-lysine-methyl ester (Ka approximately 0.2 mM(-1),
peptides encompassing Lys50O consistently show higher Ka values. Among the
investigated linear peptides, Nalpha-acetyl-Ala-Phe-Tyr-His-Ser-Ser-Lys5O-Glu-Gln
NH2 (AcAFYHSK5OEQ-NH2) exhibits the strongest interaction with K4 (Ka
approximately 1.4 mM(-1)), followed by AcYHSK50EQ-NH2 (Ka approximately 0.9 mM(
1)). Relative to the wild-type sequence, mutated hexapeptides exhibit lesser
affinity for K4. When a Lys50 --> Ser mutation was introduced (==> AcYHSS50EQ
NH2), binding was abolished. The Ile27-lle56 construct (L-NTP) contains the Lys50
site within a loop constrained by two cystine bridges. The propensity of
recombinant Pgn K1 (rK1) and K2 (rK2) modules, and of Pgn fragments encompassing
the intact K4 and K5 domains, for binding L-NTP, was investigated. We find that L
NTP interacts with rK1, rK2, K4, and K5-all lysine-binding kringles-in a fashion
that closely mimics what has been observed for the Glul-HSer57 N-terminal
fragment of Pgn (CB-NTP). Thus, both the constellation of kringle lysine binding
site (LBS) aromatic residues that are perturbed upon complexation of L-NTP and
magnitudes of kringle-L-NTP binding affinities (rK1, Ka approximately 4.3 mM(-1);
rK2, Ka approximately 3.7 mM(-1; K4, Ka approximately 6.4 mM(1); and K5, Ka
approximately 2.1 mM(-1)) are essentially the same as for the corresponding
kringle-CB-NTP pairs. Molecular modeling studies suggest that the Glu39-Lys50
stretch in NTP generates an area that complements, both topologically and
electrostatically, the solvent-exposed kringle LBS surface.
PMID- 9761477
TI - Human nucleotide excision repair protein XPA: extended X-ray absorption fine
structure evidence for a metal-binding domain.
AB - The ubiquitous, multi-enzyme, nucleotide excision repair (NER) pathway is
responsible for correcting a wide range of chemically and structurally distinct
DNA lesions in the eukaryotic genome. Human XPA, a 31 kDa, zinc-associated
protein, is thought to play a major NER role in the recognition of damaged DNA
and the recruitment of other proteins, including RPA, ERCC1, and TFIIH, to repair
the damage. Sequence analyses and genetic evidence suggest that zinc is
associated with a C4-type motif, C105-X2-C108-X17-C126-X2-C129, located in the
minimal DNA binding region of XPA (M98-F219). The zinc-associated motif is
essential for damaged DNA recognition. Extended X-ray absorption fine structure
(EXAFS) spectra collected on the zinc associated minimal DNA-binding domain of
XPA (ZnXPA-MBD) show directly, for the first time, that the zinc is coordinated
to the sulfur atoms of four cysteine residues with an average Zn-S bond length of
2.34+/-0.01 A. XPA-MBD was also expressed in minimal medium supplemented with
cobalt nitrate to yield a blue-colored protein that was primarily (>95%) cobalt
associated (CoXPA-MBD). EXAFS spectra collected on CoXPA-MBD show that the cobalt
is also coordinated to the sulfur atoms of four cysteine residues with an average
Co-S bond length of 2.33+/-0.02 A.
PMID- 9761478
TI - The structure of serine hydroxymethyltransferase as modeled by homology and
validated by site-directed mutagenesis.
AB - We describe a model for the three-dimensional structure of E. coli serine
hydroxymethyltransferase based on its sequence homology with other PLP enzymes of
the alpha-family and whose tertiary structures are known. The model suggests that
certain amino acid residues at the putative active site of the enzyme can adopt
specific roles in the catalytic mechanism. These proposals were supported by
analysis of the properties of a number of site-directed mutants. New active site
features are also proposed for further experimental testing.
PMID- 9761479
TI - A test of the relationship between sequence and structure in proteins: excision
of the heme binding site in apocytochrome b5.
AB - The water-soluble domain of rat hepatic holocytochrome b5 is an alphabeta protein
containing elements of secondary structure in the sequence beta1-alpha1-beta4
beta3-alpha2-alpha3-beta5- alpha4-alpha5-beta2-alpha6. The heme group is enclosed
by four helices, a2, a3, a4, and a5. To test the hypothesis that a small b
hemoprotein can be constructed in two parts, one forming the heme site, the other
an organizing scaffold, a protein fragment corresponding to beta1-alpha1-beta4
beta3-lambda-beta2-alpha6 was prepared, where lambda is a seven-residue linker
bypassing the heme binding site. The fragment ("abridged b5") was found to
contain alpha and beta secondary structure by circular dichroism spectroscopy and
tertiary structure by Trp fluorescence emission spectroscopy. NMR data revealed a
species with spectral properties similar to those of the full-length apoprotein.
This folded form is in slow equilibrium on the chemical shift time scale with
other less folded species. Thermal denaturation, as monitored by circular
dichroism, absorption, and fluorescence spectroscopy, as well as size-exclusion
chromatography-fast protein liquid chromatography (SEC-FPLC), confirmed the
coexistence of at least two distinct conformational ensembles. It was concluded
that the protein fragment is capable of adopting a specific fold likely related
to that of cytochrome b5, but does not achieve high thermodynamic stability and
cooperativity. Abridged b5 demonstrates that the spliced sequence contains the
information necessary to fold the protein. It suggests that the dominating
influence to restrict the conformational space searched by the chain is
structural propensities at a local level rather than internal packing. The
sequence also holds the properties necessary to generate a barrier to unfolding.
PMID- 9761480
TI - Amide proton exchange measurements as a probe of the stability and dynamics of
the N-terminal domain of the ribosomal protein L9: comparison with the intact
protein.
AB - Amide H/D exchange rates have been measured for the N-terminal domain of the
ribosomal protein L9, residues 1-56. The rates were measured at pD 3.91, 5.03,
and 5.37. At pD 5.37, 18 amides exchange slowly enough to give reliable rate
measurements. At pD 3.91, seven additional residues could be followed. The
exchange is shown to occur by the EX2 mechanism for all conditions studied. The
rates for the N-terminal domain are very similar to those previously measured for
the corresponding region in the full-length protein (Lillemoen J et al., 1997, J
Mol Biol 268:482-493). In particular, the rates for the residues that we have
shown to exchange via global unfolding in the N-terminal domain agree within the
experimental error with the rates measured by Hoffman and coworkers, suggesting
that the structure of the domain is preserved in isolation and that the stability
of the isolated domain is comparable to the stability of this domain in intact
L9.
PMID- 9761481
TI - Distance geometry generates native-like folds for small helical proteins using
the consensus distances of predicted protein structures.
AB - For successful ab initio protein structure prediction, a method is needed to
identify native-like structures from a set containing both native and non-native
protein-like conformations. In this regard, the use of distance geometry has
shown promise when accurate inter-residue distances are available. We describe a
method by which distance geometry restraints are culled from sets of 500 protein
like conformations for four small helical proteins generated by the method of
Simons et al. (1997). A consensus-based approach was applied in which every inter
Calpha distance was measured, and the most frequently occurring distances were
used as input restraints for distance geometry. For each protein, a structure
with lower coordinate root-mean-square (RMS) error than the mean of the original
set was constructed; in three cases the topology of the fold resembled that of
the native protein. When the fold sets were filtered for the best scoring
conformations with respect to an all-atom knowledge-based scoring function, the
remaining subset of 50 structures yielded restraints of higher accuracy. A second
round of distance geometry using these restraints resulted in an average
coordinate RMS error of 4.38 A.
PMID- 9761482
TI - Compactness of the kinetic molten globule of bovine alpha-lactalbumin: a dynamic
light scattering study.
AB - During folding of globular proteins, the molten globule state was observed as an
equilibrium intermediate under mildly denaturing conditions as well as a
transient intermediate in kinetic refolding experiments. While the high
compactness of the equilibrium intermediate of alpha-lactalbumin has been
verified, direct measurements of the compactness of the kinetic intermediate have
not been reported until now. Our dynamic light scattering measurements provide a
complete set of the hydrodynamic dimensions of bovine alpha-lactalbumin in
different conformational states, particularly in the kinetic molten globule
state. The Stokes radii for the native, kinetic molten globule, equilibrium
molten globule, and unfolded states are 1.91, 1.99, 2.08, and 2.46 nm,
respectively. Therefore, the kinetic intermediate appears to be even more compact
than its equilibrium counterpart. Remarkable differences in the concentration
dependence of the Stokes radius exist revealing strong attractive but repulsive
intermolecular interactions in the kinetic and equilibrium molten globule states,
respectively. This underlines the importance of extrapolation to zero protein
concentration in measurements of the molecular compactness.
PMID- 9761483
TI - Electrostatic coupling to pH-titrating sites as a source of cooperativity in
protein-ligand binding.
AB - This paper describes an alternative mechanism for the cooperative binding of
charged ligands to proteins. The ligand-binding sites are electrostatically
coupled to protein side chains that can undergo protonation and deprotonation.
The binding of one ligand alters the protein's protonation equilibrium in a
manner that makes the the binding of the second ligand more favorable. This
mechanism requires no conformational change to produce a cooperative effect,
although it is not exclusive of conformational change. We present a theoretical
description of the mechanism, and calculations on three kinds of systems: A model
system containing one protonation site and two ligand-binding sites; a model
system containing two protonation sites and two ligand-binding sites; and
calbindin D9k, which contains two Ca2+-binding sites and 30 protonation sites.
For the one-protonation-site model, it is shown that the influence of the
protonation site can only be cooperative. The competition of this effect with the
anticooperative effect of ligand-ligand repulsion is studied in detail. For the
two-protonation site model, the effect can be either cooperative or, in special
cases, anticooperative. For calbindin D9k, the calculations predict that six
protonation sites in or near the ligand-binding sites make a cooperative
contribution that approximately cancels the anticooperative effect of Ca2+-Ca2+
repulsion, accounting for more than half of the total cooperative effect that is
needed to overcome repulsion and produce the net cooperativity observed
experimentally. We argue that cooperative mechanisms of the kind described here
are likely when there is more than one ligand-binding site in a protein domain.
PMID- 9761484
TI - Architecture of beta-barrel membrane proteins: analysis of trimeric porins.
AB - We have analyzed the known three-dimensional structures of trimeric porins from
bacterial outer membranes. The distribution of surface-exposed residues in a
direction perpendicular to the membrane is similar to that in helical membrane
proteins, with aliphatic residues concentrated in the central 20 A of the
bilayer. Outside these residues is a layer of aromatic residues, followed by
polar and charged residues. Residues in the trimer interface are more conserved
than residues not in the interface. By comparing the interface and noninterface
residues, an interface preference scale has been derived that may be used as a
basis for predicting interface surfaces in monomer models.
PMID- 9761485
TI - Characterization of recombinant human cathepsin B expressed at high levels in
baculovirus.
AB - The lysosomal cysteine protease cathepsin B has been studied intensely for many
years because of its unique characteristics and its potential involvement in
disease states. A reproducible, high yield expression system for active
recombinant protein is key to biochemical and biophysical studies as well as
rational drug design. Although several microbial and mammalian expression systems
for recombinant human cathepsin B have been described, these have been limited by
low or variable yields. Further, in some of these systems hyper-glycosylation of
the enzyme near the active site affects its activity. We describe a baculovirus
expression system and purification scheme that solve all of these problems.
Yields of active, protected enzyme were reproducibly in excess of 25 mg/L. Since
this protein was not hyper-glycosylated, it had greater activity than cathepsin B
produced in yeast systems as indicated by a threefold increase in Kcat. In
addition, the biophysical properties of the baculovirus-expressed cathepsin B, as
measured by dynamic light scattering, were more amenable to crystallographic
study since the data indicated proteins of more uniform size. Therefore, this
system for the production of recombinant human cathepsin B constitutes a major
improvement in both quantity and quality over those previously reported. Further,
we demonstrate that the manner of expression and purification of this enzyme has
profound effects on its kinetic and physical parameters.
PMID- 9761486
TI - Pride and prejudice: the discovery of the primer for glycogen synthesis.
PMID- 9761487
TI - Lectins: from obscurity into the limelight.
PMID- 9761488
TI - Menin and MEN 1 gene: a model of tumour suppressor system.
PMID- 9761489
TI - Hypertension in patients with cerebrovascular accident. To treat or not to treat?
PMID- 9761490
TI - The renal risks of high-dose intravenous immunoglobulin treatment.
PMID- 9761491
TI - Polymorphonuclear neutrophils in acute renal failure: new insights.
PMID- 9761492
TI - Angiodysplasia in the renal patient: how to diagnose and how to treat?
PMID- 9761493
TI - Recirculation, a seemingly simple concept.
PMID- 9761495
TI - Renal function and renal disease in males or females--vive la petite difference.
PMID- 9761494
TI - What place diuretics in long-term CAPD?
PMID- 9761496
TI - Kt/V or solute removal index: problems in measuring and interpreting the results.
PMID- 9761497
TI - The clotted central vein catheter for haemodialysis.
PMID- 9761498
TI - How is the annual congress of your society managed? (Reflection on the ethics and
finances of medical congresses).
PMID- 9761499
TI - The impact of early normalization of haematocrit by erythropoietin on renal
damage in the remnant kidney model.
AB - BACKGROUND: Correction of anaemia in moderate to advanced renal failure is still
a matter of debate because of postulated detrimental effects of erythropoietin on
the progression of renal damage. METHODS: The renal effects of early
normalization of haematocrit (Htc) by erythropoietin (rHuEpo) were investigated
from the time of 5/6 nephrectomy up to 8 weeks post-intervention in three groups
of remnant kidney model rats: untreated controls (CON), rats receiving 100 UI/kg
body-wt of rHuEpo i.p. twice a week (EPO), and rats receiving rHuEpo in which
periodic phlebotomies maintained Htc similar to the value of the control group
(PHL). The latter group was included to evaluate the direct effects of rHuEpo on
renal damage, i.e. independent from Htc correction. RESULTS: Two weeks after
renal ablation (basal), Htc decreased in CON and PHL rats (from 49.3+/-1.4% to
43.2+/- 1.1, P < 0.05 and from 49.6+/-1.1 to 43.3+/-1.5%, P<0.05 respectively),
while it remained consistently normal in EPO rats (48.9+/-1.2% to 48.9+/-1.50/%,
P<0.05 vs other groups). Thereafter Htc did not change throughout the remaining
period in all groups. At the end of the study, with respect to basal, resting
blood pressure increased significantly by the same extent in CON (+ 13+/-2%) and
EPO rats (+ 15+/-5%), while it remained constant in PHL rats. Notably, creatinine
clearance significantly decreased in CON (-53+/-8% 8 vs basal) and EPO (-38+/-8%
vs basal), while it did not change in PHL rats. Likewise the degree of
proteinuria as well as renal morphologic alterations and glomerular
hypertrophy/sclerosis was similar in CON and EPO rats, and was significantly more
severe than in the phlebotomized group. The only difference detected between CON
and EPO group was the greater mesangial hypercellularity in rHuEpo-treated rats.
CONCLUSION: In uraemic rats, chronic treatment with rHuEpo aimed at normalization
of Htc beginning the early stage of renal failure does not inevitably account for
a rise in systemic blood pressure. In addition, neither erythropoietin per se nor
the correction of haematocrit accelerates the progression of renal damage when
blood pressure remains constant.
PMID- 9761500
TI - Cellular apoptosis and proliferation in experimental renal fibrosis.
AB - BACKGROUND: The progression of chronic renal failure (CRF) is associated with the
progressive deletion of renal cells along with the fibrosis of the kidney. We
have studied the role of programmed cell death (apoptosis) in the progression of
experimental CRF and renal scarring. METHODS: The sub-total (5/6th) nephrectomy
(SNx) model of CRF was studied in adult male Wistar rats, with renal tissue
collected from experimental and control animals on days 7, 15, 30, 60, 90, and
120 post SNx (n = 6 per group). These were examined for morphological signs of
apoptosis by light and electron microscopy. Further, we stained the nuclear
chromatin by the acridine orange fluorescent method and detected signs of DNA
cleavage by endonucleases via the principal of TUNEL staining (ApopTag). Rates of
cellular proliferation were measured simultaneously by immunohistochemical
staining for the proliferating cell nuclear antigen (PCNA). In addition, cell
division was monitored by counting of morphologically mitotic motifs detectable
by light microscopy. RESULTS: Progressive renal insufficiency associated with
glomerulosclerosis and tubulointerstitial fibrosis took place in the majority of
SNx rats. In these animals, we noted a marked and progressive increase in the
number of apoptotic glomerular, tubular as well as interstitial cells. The most
significant apoptotic changes were seen in the tubules of remnant kidneys peaking
at day 120 post-SNx. At this stage, the increase in apoptosis compared to
controls was 10.33+/-2.67 (M+/-SEM) fold for glomerular cells (P< or =0.006),
26.20+/-4.56 fold for tubular cells (P < 0.0001) and 4.66+/-0.81 fold for
interstitial cells (P< or =0.001). Parallel changes in the number of PCNA
positive renal cells were observed. Maximal PCNA staining was seen at day 120
when the increase with respect to controls was 14.00+/-4.93 fold (P< or = 0.05)
for glomerular cells, 60.01+/-12.20 fold (P< or =0.05) for tubular cells and
28.59+/-4.45 fold (P< or = 0.05) for interstitial cells. As expected, the number
of cells undergoing division and detectable by conventional light microscopy was
lower at any time point to those expressing PCNA. We also observed a close
correlation between the severity of tubular atrophy and tubulointerstitial
fibrosis with the rate of tubular apoptosis (r=0.970, R2 =0.941, P< or =0.001).
CONCLUSIONS: We have shown a time-dependent increase in apoptosis and PCNA
antigen positive staining in the sub-total nephrectomy model of chronic renal
failure correlating with the progression of renal fibrosis. PCNA staining did not
match analysis for mitosis and was considered to overestimate the number of
proliferating cells in the tissue. With this reservation in mind and taking into
account the relative time-frames in vivo of apoptosis and proliferation;
apoptosis potentially outweighs proliferation by a factor of 2 8-fold, when
examined over the same time period. Consequently, even small changes in the
finite numbers of apoptotic cells become highly significant. Our results have
shown the definite role of apoptosis within progression of renal damage and
highlighted how it may contribute to the progression of tubular atrophy and play
a role in the pathogenesis of tubulo-interstitial scarring.
PMID- 9761501
TI - Fosinopril ameliorates exogenous cholesterol-induced incipient glomerular lesions
in obese Zucker rats. Effects on eicosanoid secretion.
AB - BACKGROUND: To date, the role of dietary cholesterol as a risk factor for some
diabetic nephrophathy, such as mesangial expansion and glomerular lesions, is
unknown. Controversy also exists regarding the effects of prostaglandin-induced
changes in glomerular haemodynamics on the appearance of glomerulosclerosis.
METHODS: We have used obese Zucker rats (OZRs) as a model of early nephrophathy
to evaluate the effect of hypercholesterolaemic diet on glomerular prostaglandin
secretion and on the development of glomerular lesions. Due to the role of
angiotensin II (Ang II) in glomerular haemodynamics, we have also evaluated its
effects on glomerular eicosanoid secretion. Furthermore, as it has been suggested
recently by clinical studies that angiotensin-converting enzyme inhibitors
(ACEIs) reduce serum lipids associated with proteinuria, we have also evaluated
the effect of the ACEI, fosinopril, both in vivo and in vitro, using 24 h
glomeruli cultures. RESULTS: Results showed that a cholesterol-rich diet
significantly increased serum cholesterol, proteinuria and glomerular eicosanoid
secretion, and caused macrophage-ED1 cell deposits in the glomerular mesangium.
Segmentary lesions only appeared in those rats with the highest percentage of
glomerular xanthomatous (macrophage-ED1) cells. Ang II, per se, caused a marked
rise in glomerular prosaglandin E2 and thromboxane B2. The inhibition of Ang II
synthesis with fosinopril reduced all the parameters listed above, whereas Ang II
(10(-6)M) increased the secretion of TxB2 and tended to increase PGE2 secretion
in glomerular culture. CONCLUSIONS: In conclusion, exogenous cholesterol per se
may contribute to nephropathy by increasing eicosanoid secretion, serum lipid
profile, urinary protein excretion and the development of glomerular lesions.
Fosinopril reduced all these parameters probably by its effects on Ang II.
PMID- 9761502
TI - Effects of testosterone on glomerular growth after uninephrectomy.
AB - BACKGROUND: Renal functional prognosis is consistently more adverse in male
individuals with renal disease. Male animals develop more marked proteinuria and
glomerulosclerosis in several models of renal damage. Renal and glomerular growth
are important permissive factors for progression of renal failure. PURPOSE OF THE
STUDY: To investigate the influence of testosterone on renal and glomerular
growth. DESIGN: Renal compensatory growth after uninephrectomy (UNX) was chosen
as a model of renal growth. The effect of testosterone was assessed in control
male, in orchidectomized (OX) male, and in ovariectomized (OV) female SD rats.
Observation time was 10 months. MEASUREMENTS: Albuminuria by nephelometry;
glomerular diameter, glomerular tuft area, renal zonal analysis by quantitative
stereology. Testosterone and dihydroxytestosterone by gas chromatography and RIA.
RESULTS: In sham-operated male rats, testosterone administration did not change
the (left) kidney:body-weight ratio after uninephrectomy. In contrast, in OX male
rats, testosterone administration caused a significant increase in kidney:body
weight ratio and in albuminuria. In these animals, glomerular diameter and outer
stripe width were significantly lower in OX rats than in sham-operated controls.
Glomerular volume and outer stripe width in OX animals were significantly higher
after uninephrectomy (UNX) and were further increased in OX-UNX animals by
administration of testosterone. Similar effects on glomerular diameter, cortical
width (single) kidney:body-weight ratio were seen when OV female rats were
treated with testosterone. CONCLUSION: After gonadal ablation, administration of
testosterone amplifies compensatory glomerular and tubular growth in
uninephrectomized male and female rats, i.e. testosterone is a permissive factor.
Stimulation of glomerular growth may favour development of glomerulosclerosis.
PMID- 9761503
TI - High-calcium intake abolishes hyperoxaluria and reduces urinary crystallization
during a 20-fold normal oxalate load in humans.
AB - BACKGROUND: The aim of the study was to test whether increasing dietary calcium
intake lowers intestinal oxalate absorption and thereby prevents hyperoxaluria
and urinary crystallization during a 20-fold normal oxalate load in healthy
subjects. METHODS: Fourteen healthy male volunteers (age 23-44 years, BMI 21.5
27.7 kg/m2) collected 24-h urines while on free-choice diet as well as on two
standardized diets. The latter contained 2545 kcal, 2500 ml of mineral water, 102
g of protein, 13.6 g of sodium chloride and 2220 mg of oxalate (approximately 20
fold content of an average diet). Subjects were studied twice while on the
standardized diet, once while eating a normal amount of calcium (1211 mg/day,
oxalate-rich diet), and once while eating 3858 mg of calcium/day (calcium and
oxalate-rich diet). RESULTS: Compared with the free-choice diet (322+/-36
micromol/d), UOx x V increased to 780+/-72 micromol/d on the oxalate-rich diet
(P=0.001) and fell again to 326+/-31 micromol/d on calcium and oxalate-rich diet
(P=0.001 vs oxalate-rich diet). Urinary glycolate (a metabolic precursor of Ox)
always remained below the upper limit of the normal range and did not change
between different diets, indicating that changes in UOX x V reflect respective
variations in intestinal absorption of Ox. Uca x V was 4.60+/-0.45 mmol/d on the
free-choice diet and 3.20+/-0.32 mmol/d on the oxalate-rich diet (P=0.011 vs free
choice diet); it increased to 7.28+/-0.74 mmol/d on the calcium- and oxalate-rich
diet (P=0.001 vs free-choice and oxalate-rich diets). As indicated by the AP
(CaOx) index (Tiselius), urinary supersaturation did not vary significantly
between the three diets. In freshly voided morning urines (studied in 8/14
subjects) on the oxalate-rich diet, CaOx crystals or crystal aggregates of up to
80 microm diameter were found in 5/8 urines, whereas this never occurred on the
free-choice diet and only t once on the calcium- and oxalate-rich diet.
CONCLUSION: . Increasing calcium intake while eating Ox-rich food prevents
dietary hyperoxaluria and reduces CaOx crystallization in healthy subjects. This
further illustrates that dietary counseling to idiopathic calcium-stone formers
should ensure sufficient calcium intake, especially during oxalate-rich meals.
PMID- 9761504
TI - Adverse effects of chronic low level lead exposure on kidney function--a risk
group study in children.
AB - BACKGROUND: Children have been considered a risk group for lead (Pb) toxicity,
mainly because of neurophysiological or neuro-cognitive deficits following Pb
exposure. Blood Pb levels (b-Pb) of 100 microg/l currently have been defined as
the lowest adverse effect level. The aim of this study was to compare, with the
help of urinary markers, the kidney function of children with b-Pb just above
this threshold with that of unexposed children, to assess from a nephrological
point of view whether the current threshold is justified and whether children
really are a particularly vulnerable risk group in terms of Pb-induced kidney
damage. METHODS: In a cross-sectional study, 112 children, either from unexposed
areas (controls, n=50) or Pb-contaminated areas (n=62), the latter partly with a
known history of elevated b-Pb, were examined. Twenty nine urinary or serum
markers mostly related to the function or integrity of specific nephron segments
were determined (e.g. filtered plasma proteins, tubular enzymes, tubular
antigens, eicosanoids). RESULTS: b-Pb were 39+/-13 microg/l in controls and 133+/
62 microg/l in exposed children. The main findings were increased excretion rates
of prostaglandins and thromboxane B2, epidermal growth factor, beta2
microglobulin and Clara cell protein in the exposed children. A relationship
between b-Pb and the prevalence of values above the upper reference limits was
observed. CONCLUSIONS: With the help of urinary markers, nephron segment-specific
effects of chronic low-level Pb exposure could be detected in children. The
pattern of effects on glomerular, proximal and distal tubular and interstitial
markers was similar to that previously observed in adults. The changes, however,
occur at lower b-Pb levels than in adults. The current threshold appears to be
justified also from a nephrological point of view, and children can indeed be
considered a special risk group.
PMID- 9761505
TI - Diurnal blood pressure variation and albuminuria in normotensive patients with
insulin-dependent diabetes mellitus.
AB - BACKGROUND: Abnormalities of the systemic blood pressure are closely associated
with the development of diabetic nephropathy. Our aim was to examine the
relationship between diurnal blood pressure pattern and albuminuria in insulin
dependent normotensive diabetic patients before the development of overt
nephropathy. METHODS: Urinary albumin excretion rates were determined by
radioimmunoassay, and 24-h ambulatory blood pressure monitoring was performed.
Means and diurnal index was calculated for systolic, diastolic and mean arterial
blood pressure, for day-time, night-time, and the whole day. The results of the
normoalbuminuric (n = 39) and microalbuminuric (n = 29) groups are compared, and
correlation of the blood pressure parameters with albuminuria is analysed.
RESULTS: Twenty-four hours and night-time mean blood pressures were significantly
higher, diurnal indices characterizing the night-time blood pressure drop were
smaller in the microalbuminuric group. With multiple regression analysis a
significant positive correlation was found between albumin excretion rates and 24
h mean systolic blood pressure and a significant negative correlation between
albumin excretion rates and the diurnal index of mean arterial pressure (r2=
0.40, P<0.0001). In the normoalbuminuric group 1 (2.6%) patient, in the
microalbuminuric group 7 (24.1%/) were 'non-dippers'. CONCLUSION: We conclude
that in normotensive insulin-dependent diabetic patients the night-time decrease
of blood pressure is smaller if microalbuminuria is present. Higher nocturnal
blood pressure load is associated with the increase of albuminuria, even before
the onset of overt diabetic nephropathy or hypertension.
PMID- 9761506
TI - Renal haemodynamic responses to a chicken or beef meal in normal individuals.
AB - BACKGROUND: In normal subjects, protein loading with soybean meal does not
produce the same renal haemodynamic effects as those observed with a beef meal.
The renal responses of an acute protein load in the form of chicken meal is
unknown. METHODS: To examine whether the renal response to a chicken meal differs
from that to beef, we studied the renal function of eight normal healthy
volunteers before and after a protein load with each of these meals. In a
crossover randomized study, we measured the glomerular filtration rate (GFR;
inulin clearance), renal plasma flow (RPF; para-aminohippurate clearance) and,
plasma amino acid and glucagon levels. We also determined the amino acid content
of a sample of chicken and beef. RESULTS: GFR and RPF increased significantly 2 h
after both the chicken and beef meals (chicken, 98+/-13 vs 119+/-18 and 476+/-123
vs 570+/-99 ml/min/1.73 m2; beef, 107+/-14 vs 122+/-16 and 501+/-118 vs 560+/-97
ml/min/1.73 m2, for GFR and RPF at basal and 2 h respectively, P<0.05). Renal
vascular resistance decreased and the filtration fraction remained unchanged
after both protein loads. The changes induced by the protein challenges in the
plasma amino acid and glucagon levels were not different between the two protein
sources. The amino acid contents of chicken and beef samples were similar.
CONCLUSION: In normal subjects, chicken and beef meals induced a similar degree
of hyperfiltration.
PMID- 9761507
TI - Optimal design of a two-sample test for assessing [125I]iothalamate plasma
clearance in peritoneal dialysis.
AB - BACKGROUND: Plasma clearance of a tracer in peritoneal dialysis (PD) can be used
to assess treatment adequacy without labour-intensive fluid collections. Accuracy
and precision of plasma clearance estimates by the bolus injection technique
depend on the estimation accuracy of the area under the concentration curve and
the measurement precision of plasma concentrations. The first source of error is
due to oversimplified, e.g. monoexponential, descriptions of plasma disappearance
curves. The second source of error arises from the propagation of measurement
errors to the parameter estimates. METHODS: The theoretical bias of parameter
estimates is determined first for a monoexponential approximation of a
biexponential disappearance curve and as a function of the first sampling time at
which mixing is still incomplete. The precision of plasma clearance estimates,
expressed as coefficient of variation, is then described as a function of the
experimental variables and of the standard deviation of measurement error. This
allows the determination of the optimal two-sample test that yields most precise
estimates of plasma clearance. RESULTS: The optimal two-sample schedules for
assessing plasma clearance of [125I]iothalamate in PD patients vary between
subjects according to individual clearances and distribution volumes. Our results
suggest collecting the first sample 120 min, and the second 2-4 days, after the
bolus injection. CONCLUSIONS: The proposed two-sample test is suitable to be used
in clinical routine for assessment of adequacy of PD treatment but requires a
priori estimation of individual tracer kinetics and of laboratory measurement
errors. A fixed design with the first sample taken after 120 min and the second
sample collected 3 days after the bolus injection should yield the best
performance.
PMID- 9761508
TI - Hyperleptinaemia of end-stage renal disease is corrected by renal
transplantation.
AB - BACKGROUND: Previous studies have reported that patients with end-stage renal
disease (ESRD) have elevated plasma leptin concentrations, but the cause and
significance of the elevations are unknown. We studied leptin concentrations in
29 adults undergoing renal transplantation, to determine if restoration of renal
function reduced leptin concentrations in ESRD. METHODS: Leptin concentrations
were measured by radioimmunoassay in plasma specimens collected within 1 week
before transplant, 6 days post-transplant, and 60 days post-transplant. RESULTS:
Mean plasma leptin concentrations were higher in both male and female ESRD
patients compared with a control population of similar age and body mass index
(BMI), but most of the disparity was due to a minority of patients with grossly
elevated concentrations; the majority of ESRD patients had normal or near-normal
leptin concentrations after accounting for their adiposity with BMI. Six days
after successful renal transplantation, average plasma leptin concentrations
decreased to control levels. The grossly elevated pretransplant concentrations in
a minority of patients were greatly reduced in relation to BMI, and the reduction
persisted to 60 days post-transplant. The decrease in creatinine with transplant
did not correlate with the decrease in leptin. CONCLUSIONS: These results
demonstrate that restoration of renal function in ESRD patients reduces
hyperleptinaemia, which provides further evidence of a cause/effect relationship
between impaired renal function and abnormal leptin metabolism.
PMID- 9761509
TI - Plasma leptin concentration in kidney transplant patients during the early post
transplant period.
AB - BACKGROUND: Leptin, is produced by adipose tissue and is presumed to be involved
in the regulation of appetite and energy balance. The kidneys are involved in the
inactivation of circulating leptin, and elevated plasma leptin concentrations
were reported in uraemic patients. Finally, glucocorticosteroids as used in
transplanted patients stimulate leptin secretion. METHODS: The present study
aimed to asses the relationship between plasma leptin concentration and kidney
graft function in the early post-transplant period. We studied 40 successfully
transplanted haemodialysed uraemic patients (27 males, 13 females, mean age 34.3
+/- 1.6 years, mean body mass index 22.5 +/- 0.5 kg/m2). The circadian rhythm of
leptinaemia and insulinaemia was assessed twice: 2-4 days after kidney
transplantation and 1 day before discharge from the hospital when graft function
was good. Plasma leptin concentration was measured at 8 am, 4 pm, and 12 pm. The
control group consisted of 21 healthy subjects (13 males, 8 females, mean age
39.4+/-2.5 years, mean body mass index 24.1 +/-0.7 kg/m2). RESULTS: Before kidney
transplantation, patients had elevated plasma leptin and insulin levels. A
positive correlation was found between BMI and leptinaemia and BMI and
insulinaemia, respectively. An inverse relationship was found between leptinaemia
and age. Successful kidney transplantation was followed by a significant decline
of leptinaemia i.e. from 21.5 +/- 0.1 vs 7.1 +/- 1.3 ng/ml. Kidney
transplantation did not influence the circadian rhythm of leptinaemia.
CONCLUSION: Leptinaemia was not related to the excretory graft function or
immunosuppression. In addition to renal excretory function, other factors must be
involved in the post-transplant decline of leptinaemia.
PMID- 9761510
TI - Low-density lipoprotein subfraction profiles in chronic renal failure.
AB - BACKGROUND: Small low-density lipoprotein (LDL) particle size, a newly recognized
risk factor for cardiovascular disease in the general population, is frequently
associated with hypertriglyceridaemia, the predominant plasma lipid abnormality
present in uraemia. METHODS: Plasma lipids and LDL subfraction profiles were
examined in 33 non-dialysed patients with chronic renal failure (predial), 40
patients on continuous ambulatory peritoneal dialysis (CAPD), 42 haemodialysis
patients (HD), 47 renal transplant recipients (RTR), and 44 controls. LDL
subfractions separated by gel electrophoresis were scored by densitometric
analysis (higher scores indicate profiles comprising smaller particles). RESULTS:
All groups with renal failure had significantly elevated (mean+/-SD) LDL scores
(predial 1.36+/-0.6, CAPD 1.71+/-0.9, HD 1.68+/-0.9, RTR 1.92+0.8 vs control
0.87+0.4, all P<0.001), this being the only lipid abnormality detected in the
predialysis patients. In CAPD and HD patients, LDL scores were associated with
serum triglyceride (r=0.81, P<0.001 and r=0.70, P<0.001 respectively),
cholesterol (r=0.55, P<0.001 and r=0.49, P<0.01) and HDL-cholesterol (r= -0.43,
P<0.01 and r= -0.51, P<0.01), whilst no such relationship was seen in the
predialysis and RTR groups, suggesting that other factors were important.
CONCLUSIONS: The presence of small LDL particles appears to be an early and
unexplained feature of the uraemic dyslipidaemia. This abnormality persists after
renal transplantation and may represent an important atherogenic risk factor.
PMID- 9761511
TI - In vivo and in vitro neurotoxic action of plasma ultrafiltrate from uraemic
patients.
AB - BACKGROUND: In order to investigate the aetiology of uraemic neuropathy, we
evaluated the neurotoxic activity of plasma from uraemic patients. To this end we
prepared a concentrate (1:1000) of 2-60 kDa MW compounds from paired filtration
dialysis ultrafiltrate and evaluated its activity on peripheral nerve conduction
in vivo and in vitro. METHODS: The in vivo neurotoxicity was tested on rat
sciatic nerve by intraneural injection of the uraemic concentrate, followed, 1 to
6 days later, by electrophysiological assessment of motor response and maximum
conduction velocity. In vitro experiments were performed on isolated frog sciatic
nerve in the presence of uraemic concentrate, and the neurotoxicity was evaluated
from the rate of the decrease in the amplitude of the evoked maximal action
potential. RESULTS: In the in vivo experiments, the sciatic nerves injected with
the uraemic concentrate showed a decrease in maximum conduction velocity and a
progressive impairment in evoked motor response. In the in vitro experiments
uraemic concentrate induced a dose-dependent neurotoxic effect. CONCLUSIONS: Our
study demonstrates the presence in plasma of uraemic patients of a compound of 2
60 kDa MW with neurotoxic activity.
PMID- 9761512
TI - Bone markers in the diagnosis of low turnover osteodystrophy in haemodialysis
patients.
AB - BACKGROUND: Renal osteodystrophy includes a number of low and high turnover bone
histologic patterns which require a bone biopsy for their full identification.
The role of intact PTH and several classical and more recent bone markers in the
non-invasive diagnosis of renal bone disease in patients with CRF in HD requires
further definition since available published data are limited. METHODS: In
addition to intact PTH, alkaline phosphatase (AP) and osteocalcin (BGP), bone
alkaline phosphatase isoenzyme (BALP), tartrate resistant acid phosphatase
(TRAP), C-terminal cross-linked peptide of collagen type 1 (ICTP) and
deoxypyridinoline (DPD) were measured in the serum of 41 patients on
haemodialysis, subjected at the same time to transiliac bone biopsy for
histomorphometric, histodynamic and aluminium histochemical examination.
Histodynamic evaluation following double tetracycline label, was carried out in
37 patients. The patients had no evidence of active cytolytic and cholestatic
liver disease and a history of very limited aluminium exposure. RESULTS: The
patients had differing degrees of hyper-parathyroidism, with intact PTH ranging
from normal to very elevated levels. Serum values of the markers BGP, ICTP and
DPD, normally excreted through the kidneys, were on average very high. The
correlation coefficients of the humoral parameters vs dynamic variables, such as
BFR/BS, were high. The highest values were: intact PTH 0.798, AP 0.900, BALP
0.891, ICTP 0.807. The patients, grouped in low turnover osteodystrophy (LTO; 9),
mixed osteodystrophy (MO; 9) and prevalent hyperparathyroidism (HP; 23), showed
significant difference in the levels of most humoral and static and dynamic
parameters (ANOVA). Bone aluminium histochemistry was negative in all cases.
Discrimination of LTO patients from the other groups by humoral parameters, at
the highest value of accuracy, showed 100% sensitivity and 93.7% specificity with
a cut-off of 12.9 ng/ml for BALP; 88.9% sensitivity and 93.7% specificity with a
cut-off of 21.5 ng/ml for DPD, and 88.9% sensitivity and 90.6% specificity with a
cut-off of 79.7 pg/ml for intact PTH. The other markers had lower values. A
standardized z-score approach for evaluation of all humoral parameters was also
carried out. Using all variables, a correct classification of MO/HP and of LTO
was possible in 93.8 and 88.9% of the cases, respectively. Predictive power was
96.8 and 80%, respectively for MO/HP and LTO. When the only variables used were
intact PTH and BALP, a correct classification of MO/HP and LTO was possible in
90.6% and 88.9%, respectively. Predictive value of MO/HP was 96.7% and for LTO
72.7%. Predictive values using PTH and AP were 96.3% and 57.2%, respectively.
CONCLUSION: Intact PTH and several relatively new bone markers are of certain
value in the non-invasive diagnosis of renal osteodystrophy. However some of the
humoral markers carry the same quality of information and the use of intact PTH
and BALP may be adequate in the discrimination of bone histologic patterns. In
cases exempt from liver disease, PTH and AP may be used as a less costly
alternative. Bone biopsy could be chiefly limited to cases with borderline
humoral values and to all those with a suspected aluminium overload.
PMID- 9761513
TI - Effect of RenaGel, a non-absorbed, calcium- and aluminium-free phosphate binder,
on serum phosphorus, calcium, and intact parathyroid hormone in end-stage renal
disease patients.
AB - BACKGROUND: Control of dietary phosphate absorption in end-stage renal disease
patients is essential to prevent the deleterious sequelae of phosphorus
retention. Efficacy of currently available calcium- and aluminium-containing
phosphate binders is constrained by the side-effects associated with the
absorption of calcium and aluminium. The current study examined the efficacy of
RenaGel, a calcium- and aluminium-free, polymeric phosphate binder, in end-stage
renal disease patients. METHODS: Administration of calcium- or aluminium
containing phosphate binders ceased during a 2-week washout period. RenaGel, at
starting doses of one, two, or three 500-mg capsules three times per day with
meals, was administered for 8 weeks. RenaGel dose was titrated up 1 capsule per
meal at the end of each 2-week period if necessary to achieve phosphorus control.
A second 2-week washout period followed the end of RenaGel treatment. RESULTS:
Mean serum phosphorus rose from a pre-washout level of 6.9 mg/dl (2.23 mmol/l) to
8.1 mg/dl (2.62 mmol/l) at the end of the initial 2-week washout. With RenaGel
treatment, serum phosphorus declined and returned to pre-washout levels after 4
weeks. Serum phosphorus reached a nadir of 6.5 mg/dl (2.10 mmol/l) after 7 weeks
of RenaGel treatment. Serum phosphorus rose to 8.2 mg/dl (2.65 mmol/l) 2 weeks
after cessation of RenaGel treatment. As anticipated, calcium declined during the
initial washout period when calcium-based phosphate binders were stopped for the
majority of patients. The rise in serum phosphorus and decline in serum calcium
during washout resulted in an increase in median intact parathyroid hormone
(iPTH) levels from 292 pg/ml to 395 pg/ml. iPTH fell to 283 pg/ml after 6 weeks
of RenaGel treatment despite a persistently lower serum calcium. RenaGel
treatment also reduced serum total and LDL cholesterol by 25 mg/dl (0.65 mmol/l)
and 23 mg/dl (0.59 mmol/l) respectively. CONCLUSIONS: RenaGel appears to be an
effective phosphate binder free of calcium and aluminium. Phosphorus control with
two to four RenaGel capsules per meal appears to result in comparable phosphorus
lowering seen with calcium- or aluminium-based phosphate binders. RenaGel may
offer an alternative for the control of phosphorus retention in end-stage renal
disease patients.
PMID- 9761514
TI - Haemodialysis dose is independent of type of surgically-created vascular access.
AB - BACKGROUND: In the United States, the use of polytertraflouroethylene (PTFE)
graft compared with native arteriovenous fistula (AVF) for haemodialysis vascular
access has been increasing despite a greater than twofold higher incidence of
thrombosis and infection associated with PTFE grafts. METHODS: We studied 214
haemodialysis patients with not more than two revisions of their vascular access,
to determine whether any relationship exists between the type of haemodialysis
vascular access and dialysis dose assessed primarily by urea reduction ratio (per
cent reduction in blood urea nitrogen concentration after a dialysis session).
Serum albumin concentration was used as a secondary outcome measure of dialysis
adequacy. Urea reduction ratio and predialysis serum albumin concentration were
measured at onset of study and at 4-week intervals and mean values were
calculated for each subject. RESULTS: The 214 patients (118 males, 96 females)
included 173 Blacks (81%), 26 Whites (15%), and 15 Hispanics (7%), of mean (+/
SD) age 55.6+/-15.5 years. Of these 214 subjects, 111 (52%) had a native AVF,
while 103 (48%) had a PTFE graft. Both mean urea reduction ratio (native AVF=69
+/-6.7% vs PTFE graft=70+/-7.3%; P=0.31), and mean serum albumin concentration
(native AVF=4.02+/-0.39 g/dl vs PTFE graft=4+/-0.33 g/dl; P= 0.59) were
equivalent in both groups. Separate multiple logistic regression analyses with
type of vascular access as one of the independent variables, found no significant
relationship between type of vascular access and either a urea reduction ratio >
65% (P= 0.67), or a serum albumin concentration >4g/dl (P=0.89), after adjustment
for age of vascular access, access revision, location of access, dialyser urea
clearance, length of dialysis treatment, body weight, and age. CONCLUSION: We
conclude that PTFE grafts do not permit delivery of better dialysis than native
AVF. The increasing use of PTFE grafts in the United States does not have any
clinical justification.
PMID- 9761515
TI - Acute effects of haemodialysis on cutaneous microcirculation in patients with
peripheral arterial occlusive disease.
AB - BACKGROUND: Peripheral arterial occlusive disease (PAOD) is an increasing problem
in patients on maintenance haemodialysis. Alterations in microvascular perfusion
accompany and complicate arteriosclerosis of large vessels and might contribute
to the disease process. The aim of the study was to investigate the acute effects
of haemodialysis on the cutaneous microcirculation in 26 patients with and
without intermittent claudication. METHODS: Cutaneous perfusion was assessed by
measuring transcutaneous oxygen pressure (tcPO2) and skin temperature at the
dorsum of the foot. After standardized cooling to 15 degrees C of a 2cm2 skin
area, the time to reach baseline skin temperature was evaluated as an indirect
parameter of reactive hyperaemia. RESULTS: During haemodialysis, tcPO2 dropped
significantly in both groups. The decrease in tcPO2 was more pronounced in
patients with PAOD (20% vs 15% n.s.). The reactive hyperaemia response was
reduced significantly in patients with intermittent claudication indicated by a
prolonged time to reach baseline skin temperature after cooling. Values of tcPO2
and reactive hyperaemia did not reach baseline values at the end of haemodialysis
in either group. CONCLUSIONS: Nutritive skin perfusion is impaired during
haemodialysis. These changes are more pronounced in patients with PAOD and
persist after dialysis. These findings are relevant for the treatment of patients
with vascular disease on maintenance haemodialysis.
PMID- 9761516
TI - Renal insufficiency after heart transplantation: a case-control study.
AB - BACKGROUND: In Rotterdam 304 heart transplants have been performed since 1984.
End-stage renal failure, necessitating renal replacement therapy, has developed
in 24 patients (8%) after an interval of 25-121 months (median 79 months). After
starting renal replacement therapy one-year survival was only 60%. Overall
survival after heart transplantation, however, was favourable: 5 and 10 year
survival rates of 79% and 50% respectively. METHODS: A case-control study was
performed to identify possible risk factors in cases who went on to develop end
stage renal failure compared to controls. RESULTS: We found that renal failure
was not limited to elderly patients with ischaemic heart disease, but also
occurred in young patients having dilated cardiomyopathy. A significant rise in
the serum creatinine was found in cases compared to controls as early as 3 months
after transplantation. Cyclosporin dose and trough levels were not different
between cases and controls. Neither were there differences in the use of calcium
antagonists or other antihypertensive drugs, allopurinol or diuretics. Rejection
incidence was also similar between the two groups. CONCLUSIONS: Renal failure
after heart transplantation is a long term complication of cyclosporin use that
is not limited to elderly patients with ischaemic heart disease. Cyclosporin dose
and trough levels in the cases were not different from patients maintaining
stable good renal function, indicating that cyclosporin nephrotoxicity is the
result of an individually determined susceptibility to cyclosporin. Suggestions
for future strategies to prevent renal failure are given.
PMID- 9761517
TI - The effect of felodipine on renal function and blood pressure in cyclosporin
treated renal transplant recipients during the first three months after
transplantation.
AB - BACKGROUND: Due to their vasodilatory effect, calcium antagonist may have a
renoprotective against cyclosporin (CsA)-induced nephrotoxicity and rise in blood
pressure (BP) seen in renal transplantation. METHODS: In order to evaluate the
effect of the calcium antagonist felodipine on renal function and BP during
cyclosporin treatment, 79 CsA-treated renal transplant recipients were
investigated during the first 3 months after transplantation in a randomized,
double-blind, placebo-controlled study with two parallel groups. Felodipine (ER
tablets, 10 mg) or placebo was given prior to transplantation and each day during
the study period. The patients were assessed twice, i.e. at 4-6 weeks and at 10
12 weeks after transplantation. Renal plasma flow (RPF) and glomerular filtration
rate (GFR) were measured by constant infusion technique. Tubular function was
estimated from clearance of lithium. RESULTS: At 6 weeks after transplantation,
felodipine caused a significantly higher RPF [felodipine: 219 +/- 70 ml/min;
placebo: 182+/-56 ml/min (mean+/-1 SD); P=0.03]. No differences were found in
GFR, filtration fraction (FF), tubular sodium handling, or sodium excretion.
Felodipine lowered BP significantly. At 12 weeks after transplantation,
felodipine caused a significantly higher GFR (felodipine: 49+/-18 ml/min;
placebo: 40+/-16 ml/min; P=0.05) and RPF (felodipine: 225+/-77 ml/min; placebo:
175+/-48 ml/min; P<0.01). No difference was found in FF. Felodipine lowered BP
significantly. No differences were found with regard to duration of primary
anuria, hospitalization time, number of rejection episodes, plasma creatinine day
7 post-transplant, or treatment doses of CsA. CONCLUSIONS: It is concluded that
in renal transplant recipients treated with CsA, felodipine significantly
increased both GFR and RPF 3 months after transplantation when compared with
placebo, despite a concomitant lowering of BP. A possible antagonizing affect of
felodipine against CsA-induced nephrotoxicity in these patients is suggested.
PMID- 9761518
TI - Automated peritoneal dialysis: a Spanish multicentre study.
AB - BACKGROUND: A prospective sequential study on continuous ambulatory peritoneal
dialysis (CAPD) and three techniques of automated peritoneal dialysis (APD) was
conducted to assess peritoneal clearances, the influence of peritoneal
permeability on nocturnal APD clearances and the suitability of the peritoneal
equilibration test (PET) for predicting clearances on APD. METHODS: After
performing a PET, a series of clinical, biochemical and dialysis adequacy markers
were evaluated after 2 months on CAPD, continuous cycling peritoneal dialysis
(CCPD) and tidal volume peritoneal dialysis (TPD) with 50% and 25% tidal volumes.
Forty five patients participated and 33 completed the study. RESULTS: Serum urea
and creatinine decreased significantly whereas haemoglobin and glucose increased.
Mean peritoneal urea clearance (1/week) was 55.40+/-8.76 on CAPD, 74.82+/-12.62
on CCPD, 69.20+/-14.63 on TPD (tidal 50%) and 66.89+/-13.23 on TPD (tidal 25%);
mean creatinine clearance (1/week/1.73 m2) was 42.80 +/- 9.95, 52.19 +/- 11.11,
51.31 +/- 13.3 and 49.17 +/- 11.83, respectively. Both clearances were
significantly lower on CAPD than on APD (P<0.001). CCPD was the automated
technique that provided the best nocturnal urea clearance (P<0.01). Nocturnal
creatinine clearance did not show significant differences between CCPD and TPD
(tidal 50%), being better with both techniques than with TPD (tidal 25%). There
were statistically significant differences between nocturnal dialysate to plasma
(D/P) ratios and those corresponding to the nearest times in the PET. The urea
D/P ratio at 180 min and the creatinine D/P ratio at 240 min of the PET were the
parameters that better estimated nocturnal clearances on APD. CONCLUSIONS: This
study confirms that TPD does not improve the results of CCPD. Significant
differences between D/P ratios during actual nocturnal cycles and PETs were
observed.
PMID- 9761519
TI - Icodextrin use in CCPD patients during peritonitis: ultrafiltration and serum
disaccharide concentrations.
AB - BACKGROUND AND METHODS: In a randomized study on the biocompatibility of
icodextrin (I) versus glucose (G) in CCPD we used icodextrin or glucose for the
long daytime dwell. During the night-time dwells glucose was used in all
patients. In case of peritonitis icodextrin was continued. In all patients
ultrafiltration (UF) was recorded and serum icodextrin metabolites were
determined every 3 months and during peritonitis in I-users when available.
RESULTS: Thirty-eight patients ( 19 G, 19 I) entered the study and suffered 30
peritonitis episodes (16 G, 14 I). During peritonitis (P), daytime dwell UF
decreased significantly in G (P=0.001), but remained stable in I patients
compared to non-peritonitis (NP) episodes. Total 24-h UF decreased in G (P=0.001)
and in I patients (P=0.04), as the result of a decreased daytime UF and night
time UF, respectively. There was no difference in the used glucose concentrations
during the P versus NP episodes. In five I-patients serum disaccharides increased
from 0.05+/-0.01 to 1.26+/-0.23mg/ml during follow up. During peritonitis serum
disaccharide concentrations did not increase further (1.47+/-0.24 mg/ml, P=
0.56). In I patients total carbohydrate minus glucose rose to 5.72 +/- 1.2 mg/ml
during follow up, and to 6.63 +/- 1.04 mg/ml during peritonitis (P=0.7). These
concentrations are comparable to CAPD patients despite the longer dwelltime in
CCPD (8-10 versus 14-16 h, respectively). Adverse reactions attributable to
icodextrin were not encountered. CONCLUSIONS: In contrast to glucose, icodextrin
preserved the daytime dwell ultrafiltration during peritonitis. Serum icodextrin
metabolites increased during icodextrin use, but remained stable during
peritonitis. Adverse effects were not observed.
PMID- 9761520
TI - Lipid profile in haemodialysis patients treated with recombinant human
erythropoietin.
AB - BACKGROUND: The long-term effect of recombinant human erythropoietin (rhEPO) on
the blood-lipid profile has not been well documented. The aim of this study was
to evaluate whether rhEPO therapy affects the lipid pattern. METHODS: A group of
102 maintenance haemodialysis patients were treated for 2 years with rhEPO given
intravenously at the end of the dialysis session. Attempts were made to keep the
haemoglobin (Hb) at 10-11 g/dl and/or the haematocrit (Hct) at 30-35%. Twenty
maintenance haemodialysis patients not treated with rhEPO were examined as
controls. Total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides,
apolipoproteins A1 and B, and lipoprotein (a)[Lp (a)] were assessed at baseline
(without rhEPO), and 1 and 2 years after the beginning of treatment. Hb, Hct and
ferritin were measured monthly, and Kt/v was evaluated monthly and kept above
1.1. RESULTS: During follow-up, in both groups, there was a significant increase
in Apo A1 and no significant changes in the other lipid parameters. In the
treated group, Hb and Hct increased significantly after the fourth month of
treatment. CONCLUSIONS: Erythropoietin therapy does not affect significantly the
levels of total cholesterol, LDL- and HDL-cholesterol, triglycerides, Apo B and
Lp (a) in maintenance hemodialysis patients.
PMID- 9761521
TI - Peritoneal protein loss in children with nephrotic syndrome during peritoneal
dialysis.
AB - BACKGROUND: The passage of proteins across the glomerular filtration barrier is
mainly determined by the size of the protein. In nephrotic syndrome (NS) the
glomerular permselectivity is affected, causing proteinuria. Some authors suggest
the existence of a generalized basement membrane defect. The permeability
characteristics of the peritoneal basement membrane in children with NS are not
known. METHODS: The transperitoneal transport of proteins with a different
molecular weight (beta2-microglobulin MW 11800 D, albumin MW 69000 D, IgG MW
160000 D, and alpha2-macroglobulin MW 820000 D) was studied in a study group
(group A) consisting of six stable nephrotic children (three with
glomerulosclerosis and three with congenital nephrotic syndrome, one of them with
mesangial sclerosis) and compared to a control group (group B) consisting of
eight stable children on peritoneal dialysis. After a dwell of 6 h with Dianeal
1.36% dialysate and serum samples were collected. For each patient the dialysate
to plasma (D/P) ratios of the four proteins were calculated. The D/P ratios of
the nephrotic patients in group A were compared to the D/P ratios of the patients
in the control group B. Data were expressed as mean +/- SD. RESULTS: The values
for the D/P ratios (in percentage) of beta2-microglobulin, albumin, IgG and
alpha2-macroglobulin in group A were 19.6+/-9.9, 2.7+/-1.7, 1.6+/-0.9, and 0.5+/
0.4, compared to 24.9+/-10.2, 4.0+/-2.3, 2.2 +/- 1.2, and 0.7 +/- 0.3 in the
control group B. The ratios were plotted against MW on a double logarithmic
scale. In all patients a linear relationship between molecular weight and D/P
ratio of the proteins was obtained. The D/P ratios of the study group did not
differ significantly from the control group. CONCLUSION: We conclude that the
size selectivity of the capillary permeability is not affected in the peritoneal
membrane in children with NS due to glomerulosclerosis and congenital nephrotic
syndrome.
PMID- 9761522
TI - Methylenetetrahydrofolate-reductase gene C677T variant and kidney-transplant
survival.
AB - BACKGROUND. Hyperhomocysteinaemia, a risk factor for atherosclerosis, is common
in haemodialysis and renal-transplant patients. As atherosclerotic lesions in
hyperhomocysteinaemia resemble those of chronic allograft injury, we examined the
hypothesis that the C677T variant of the methylenetetrahydrofolate reductase
(MTHFR) gene, which is linked to elevated plasma homocysteine levels in patients
with renal failure, determines renal allograft survival. METHODS: DNA was
prospectively collected from 336 patients undergoing renal transplantation in our
clinic between 1988 and 1994 and their corresponding donors. Patient and
allograft survival was analysed by blinded review of all case records over a
follow-up period of 36 months. Additionally, we recruited 83 patients surviving
with a functional kidney allograft for at least 10 years (mean: 156, range 120
240 months). MTHFR-C677T genotype was determined by a PCR-RFLP technique. The
influence of genotype on transplant survival was analysed by Kaplan-Meyer life
table analysis and two-tailed global log-rank testing. RESULTS: Frequency of the
MTHFR-C677T allele in the cohort group was identical in recipients (0.35) and
donors (0.34), and comparable to that in the longterm allograft survivors (0.37).
Furthermore, life-table analysis revealed a similar allograft survival over 36
months between the genotype groups (CC 74%, CT 69%, TT 75%). Other risk factors
including donor and recipient age, hypertension, body-mass index, and number of
rejection therapies were evenly distributed between the different genotype
groups. CONCLUSIONS: These findings do not support the hypothesis that the C677T
variant of the MTHFR gene is an important determinant of renal-transplant
survival.
PMID- 9761523
TI - Acute renal failure in Henoch-Schonlein purpura due to interstitial haemorrhage
of the kidney.
PMID- 9761524
TI - Relapsing nephrotic syndrome in a patient with Kimura's disease and IgA
glomerulonephritis.
PMID- 9761525
TI - Prolonged acute renal failure after i.v. immunoglobulin therapy in the refeeding
phase of anorexia nervosa.
PMID- 9761526
TI - Severe renal failure and polyneuritis induced by foscarnet.
PMID- 9761527
TI - Tolosa-Hunt syndrome in uraemic patients undergoing maintenance haemodialysis.
PMID- 9761528
TI - The dialysed patient with both Castleman disease and Kaposi sarcoma.
PMID- 9761529
TI - Diabetic muscle infarction: an unusual cause of leg swelling in a diabetic on
continuous ambulatory peritoneal dialysis.
PMID- 9761530
TI - Massive haemoperitoneum due to rupture of splenic infarct during CAPD.
PMID- 9761531
TI - Isolated urinary aspergillosis in a renal transplant recipient.
PMID- 9761533
TI - Acute renal failure due to severe Landry-Guillain-Barre syndrome.
AB - BACKGROUND: Blood urea nitrogen (BUN) >60 mg/dl has been reported to occur
commonly in patient's with severe Landry-Guillain-Barre syndrome. AIMS: To find
out the cause for this high BUN we compared the renal function tests of 30
consecutive cases with severe Landry-Guillain-Barre syndrome to those of 30
controls. RESULTS: Acute renal failure occurred in seven patients with Landry
Guillain-Barre syndrome and none of the control group. Acute renal failure was
found more in cases with Landry-Guillain-Barre syndrome compared to controls
(P=0.0049). Six out of seven cases with Landry-Guillain-Barre syndrome and acute
renal failure had dysautonomia and became oliguric while being in a hypotensive
state. Of 30 patients with Landry-Guillain-Barre syndrome seven cases died. From
eight patients with dysautonomia six cases who had acute renal failure died. The
mortality rate was higher in cases with dysautonomia and acute renal failure (P =
0.0001 and 0.00001, respectively). Interestingly no glomerular disease was found.
CONCLUSION: In conclusion acute renal failure can occur commonly in cases with
severe Landry-Guillain-Barre syndrome particularly in those with dysautonomia,
causing high mortality.
PMID- 9761532
TI - Isolated cerebral aspergillosis without a portal of entry--complete recovery
after liposomal amphotericin B and surgical treatment.
PMID- 9761534
TI - The patient with a clotted PTFE graft developing fever.
AB - Haemodialysis access graft infection is easily recognizable when local symptoms
(warmth, swelling, pain, or drainage) predominate, and endocarditis is a well
established complication of infected grafts. We report a case of bacterial
endocarditis complicating silent infection in clotted haemodialysis access graft.
It is suggested that, clotted non-functioning grafts may be the harbingers of
silent infection, and should be suspected as the source of infection in every
haemodialysis patient that presents with fever, even in the absence of clinical
signs of graft site infection.
PMID- 9761535
TI - The dialysis patient with persisting elevation of bone alkaline phosphatase after
parathyroidectomy.
PMID- 9761536
TI - A reflection on endoscopic resection.
PMID- 9761537
TI - Segmental glomerulopathy of early rejection.
PMID- 9761538
TI - Iatrogenic hyperkalaemia--points to consider in diagnosis and management.
PMID- 9761539
TI - Bright's disease and albuminuria as seen by the famous neurologist Jean-Martin
Charcot.
PMID- 9761540
TI - Preservation of renal function: the spectrum of effects by calcium channel
blockers.
PMID- 9761541
TI - Systemic amyloidosis secondary to xantogranulomatous pyelonephritis.
PMID- 9761542
TI - Exclusion of the uteroglobin gene as a candidate for fibronectin glomerulopathy
(GFND)
PMID- 9761543
TI - Nephrotic syndrome associated with chronic lymphocytic leukaemia.
PMID- 9761544
TI - Recurrent ventricular tachycardia complicating atypical haemolytic-uraemic
syndrome.
PMID- 9761545
TI - Systemic lupus erythematosus and thrombocytopenic purpura in two members of the
same family following hepatitis B vaccine.
PMID- 9761546
TI - Interstitial nephritis and retinitis pigmentosa.
PMID- 9761547
TI - Protein C administration in meningococcal septicaemia.
PMID- 9761548
TI - Autosomal dominant polycystic kidney disease presenting with prolonged
macrohaematuria and perinephric haematoma.
PMID- 9761549
TI - Unmasking of thyrotoxicosis after initiation of regular haemodialysis treatment?
PMID- 9761550
TI - Importance of dry-weight assessment in well-being, appetite, nutritional status,
and anaemia correction in haemodialysis patients.
PMID- 9761551
TI - Tissue factor pathway inhibitor and tissue factor in HD and CAPD.
PMID- 9761552
TI - Audit of quality of hospital haemodialysis in Scotland. The Scottish Renal
Registry.
PMID- 9761553
TI - Delayed renal function and allograft survival: does the type of post transplant
dialysis influence outcome?
PMID- 9761554
TI - Discontinuing trimethoprim-sulfamethoxazole prophylaxis does not lead to
increased risk of rejection in renal transplant patients with stable graft
function.
PMID- 9761555
TI - Transient hyperphosphatasaemia in a 7-year-old boy following renal
transplantation.
PMID- 9761556
TI - Three-dimensional analysis of cleft palate topology in newborn infants with
reference to the cranial skeleton.
AB - OBJECTIVE: To describe a method of determining the three-dimensional topology of
the palatal crest relative to a reproducible anthropomorphic coordinate system in
newborn infants with unilateral cleft palate. For this purpose, physical models
of the maxilla and face were analyzed by computer morphometry. DESIGN: The study
was limited to infants referred to the craniofacial center during the first 11
days after birth. SETTING: The study was performed at a craniofacial center
servicing a large geographic area. PARTICIPANTS: The method was applied to 12
infants with unilateral cleft lip, alveolus, and palate (eight patients with left
side clefts and four with right-side clefts). MAIN OUTCOME MEASURES: The three
dimensional topology of the palatal crest referenced to an anthropometric
coordinate system was the primary outcome measure. The anthropometric reference
system is defined by the tragus points and the midpoint of a line connecting the
endocanthia. RESULTS: The topology of the maxillary crests of the patients was
characterized by considerable variability. The center of the premaxilla as
defined by the attachment of the frenulum was frequently displaced by several
millimeters from the midsagittal plane. The displacement was to the left in
infants with right-side clefts and to the right in infants with left-side clefts.
The premaxilla can be rotated by more than 30 degrees relative to the normal
position. No significant retroposition of the minor segment as determined by the
location of the tuber points was found. Several morphometric anomalies were found
to be correlated linearly. CONCLUSIONS: We propose that the morphologic
deviations are in part caused by the neuromotor activity of the tongue and of the
interrupted M. orbicularis oris. The data can serve as the starting point for a
longitudinal study of craniofacial development in children with cleft palate and
for studies on the efficacy of different therapeutic approaches.
PMID- 9761557
TI - Quantitative description of the morphology of the human palate by a mathematical
equation.
AB - OBJECTIVE: To derive a three-dimensional mathematical description of normal human
hard tissue palatal size and shape. METHODS: The maxillary dental casts of 30
adolescents free from respiratory problems, who had a complete (28 teeth)
permanent sound dentition with normal occlusion, were studied. The x, y, z
coordinates of several standardized palatal and dental landmarks were obtained
with a computerized three-dimensional digitizer. Palatal landmarks were used to
derive a mathematical equation of palatal shape in the frontal and sagittal
planes. Palatal width, length, frontal and sagittal heights, and sagittal slope,
as well as dental arch transverse and anteroposterior dimensions, were computed.
RESULTS: Neither the size nor the shape of the palate was significantly
influenced by gender. Only the intercanine distance was larger (p < .025) in
males than in females. CONCLUSIONS: Data collected in the present investigation
could represent a first database for the quantitative description of normal human
palatal morphology in subjects with a complete permanent dentition.
PMID- 9761558
TI - A retrospective comparison of craniofacial form in Northern Irish children with
unilateral cleft lip and palate.
AB - OBJECTIVE: This study evaluated the craniofacial form of a sample of Northern
Irish children with unilateral cleft lip and palate (UCLP). The quality of the
outcomes achieved was compared with the outcomes reported for the six centers
involved in the European multicenter study (Mars et al., 1992; Molsted et al,
1992). DESIGN: Retrospective analysis. PATIENTS: All children born with complete
skeletal UCLP in Northern Ireland during the years 1983 to 1987. MAIN OUTCOME
MEASURES: Cephalometric analysis was used to determine the craniofacial form and
soft tissue profile. The quality of the dental arch relationships was
independently assessed using the Goslon ranking system. RESULTS: The sample
comprised 25 children with complete skeletal UCLP who had cephalometric
radiographs and study casts recorded at a mean age of 9.4 years (range, 8 to 11
years). Cephalometric analysis revealed no important skeletal differences between
the Northern Irish UCLP children and the published results from the six Eurocleft
centers. The soft tissue profile of the Northern Irish UCLP children was
significantly more convex than the soft tissue profile recorded for center D in
the Eurocleft study. The Goslon ranking system revealed that 18 (72%) of the
Northern Irish UCLP children had good or satisfactory dental arch relationships.
CONCLUSIONS: No clinically important differences were detected between the mean
cephalometric skeletal parameters of the Northern Irish UCLP children and those
published for the six cleft centers involved in the Eurocleft study. On average,
the Northern Irish UCLP children were found to differ significantly from
Eurocleft's center D in their soft tissue facial contour and sagittal lip
profile. The quality of the dental arch relationships of the Northern Irish
sample was between the best and the less good Eurocleft centers.
PMID- 9761559
TI - HONC measures in 4- to 6-year-old children. Horii Oral Nasal Coupling Index.
AB - OBJECTIVE: To collect normative data using Horii's Oral Nasal Coupling Index
(HONC) from 4- to 6-year-old children without cleft palate to be used in the
evaluation of young children with cleft palate. In addition, to determine whether
HONC values in children are similar to those of adults and thus show that the
HONC ratio successfully normalizes nasal accelerometric signals across age,
gender, and vocal intensity. DESIGN: Measurement of accelerometric and acoustic
signals from novel nasal and nonnasal utterances, which the children repeated
after the experimenter. Measurements also included four sustained [m]
productions, which were used to calibrate correction factors used to equate nasal
and oral signals during a sustained [m] production. SETTING: Laboratory at a
state university. PARTICIPANTS: Ten girls and 10 boys, aged 4 to 6 years, with
normal speech, language, and hearing. RESULTS: Differences of 13 dB (HONC) were
found to separate nasal from nonnasal sentences. No significant difference in
HONC score was found across gender for nasal/nonnasal sentences and [m]
productions. The correction factors generated during [m] calibration procedures
did not differ between girls and boys. CONCLUSIONS: Horii Oral Nasal Coupling
Index differences between nasal and nonnasal utterances appear to be valid and
reliable measures in both children and adults for detection of disorders of nasal
resonance.
PMID- 9761560
TI - Electromyographic investigation of masticatory muscles in unilateral cleft lip
and palate patients with anterior crossbite.
AB - OBJECTIVE: To evaluate the characteristics of masticatory muscle activity in
operated unilateral cleft lip and palate (UCLP) patients with anterior crossbite
compared with normal individuals. SUBJECTS: Sixteen male and 13 female Chinese
patients with UCLP and anterior crossbite. Fifteen male and 13 female Chinese
individuals without cleft abnormalities served as a control group. DESIGN:
Electromyographic activity of the masseter muscles and anterior temporalis
muscles was recorded bilaterally in different mandibular positions using bipolar
surface electrodes. RESULTS: Compared to noncleft controls, patients with UCLP
demonstrated (1) higher activation levels of masseter and temporalis muscles in
the rest position, (2) lower potential function of masseter and temporalis, (3)
inharmonious activity of the masticatory muscles during mandibular border
movement, (4) a higher asymmetry index of the masseter and temporalis muscles,
and (5) longer silent periods of the two muscles. CONCLUSIONS: The function of
masticatory muscles is different in patients with UCLP with anterior crossbite.
Muscle function should be considered when evaluating cleft patients for
orthodontic treatment and orthognathic surgery.
PMID- 9761561
TI - Muscle fiber type distribution in the normal human levator veli palatini muscle.
AB - OBJECTIVE: This study examined the muscle fiber type distribution within the
normal adult levator veli palatini muscle. METHODS: Levator veli palatini muscle
tissue was harvested from the palates of 12 (seven female, five male) adult
noncleft cadavers. Adjacent sections were stained for adenosine triphosphatase at
pH 10.4 or 4.2. After mounting, magnifying, and photographing, Type I versus Type
II fiber types were differentiated by the intensity of, or by the inhibition of,
staining of matched fibers at each pH level. Type I fibers stained light at pH
10.4 and dark at pH 4.2, while Type II fibers stained light at pH 4.2 and dark at
pH 10.4. MAIN OUTCOME MEASURES: The number of fibers counted for each specimen
ranged from 60 to 616. The numbers of Type I and Type II stained fibers appearing
in each muscle tissue sample were determined and expressed as a percentage of the
total number of fibers identified. A few identified fibers could not be labelled
as either Type I or Type II. RESULTS: The overall proportion of Type I fibers,
averaged across all specimens, was 59.8%. Male specimens had 67.4% Type I fibers
and 31.8% Type II fibers, while female specimens had 54.4% Type I fibers and
44.4% Type II fibers. CONCLUSIONS: Observed fiber type distributions were similar
to those reported for other articulatory muscles, but differed slightly from
previously reported distributions for normal levator veli palatini. The
distributions observed in this study provide a baseline against which to relate
fiber type data from the levator veli palatini of cleft palates to the functional
status of the velopharyngeal mechanism.
PMID- 9761562
TI - Adverse outcomes following endoscopic repair of a fetal cleft lip using an ovine
model.
AB - OBJECTIVE: The purpose of this study was to determine if endoscopic techniques
could be used to repair an epithelialized lip cleft with accuracy and with an
outcome comparable to fetuses treated through an open hysterotomy. INTERVENTIONS
AND RESULTS: In contrast to previous open fetal cleft lip repairs in the same
model, none of the five fetuses reported here had a good aesthetic result.
Although there was no evidence of scar histologically, the edges of the lip were
poorly approximated. The epithelial lining and underlying dermis of the wound
margins were notably inverted. The orbicularis oris muscle, which had been
reapproximated, appeared thin and hypoplastic. Most of the vermilion elements
were poorly aligned, and in one animal, there was a complete dehiscence of the
repair. CONCLUSIONS: In a more representative model of cleft lip that is not an
acute lip wound, in utero endoscopic suture repair of the ovine lip gave a poor
result using current technology. Only a meticulously performed, multilayered,
open repair of a cleft appears to give a good cosmetic and functional outcome.
Further studies to improve the endoscopic repair as our technology advances are
therefore warranted.
PMID- 9761563
TI - Survey of dentists' experience with cleft palate children in Chile.
AB - OBJECTIVE: This study was designed to study the experience of dentists with
children with palatal clefts seeking treatment in Santiago, Chile. DESIGN: A 13
item questionnaire was sent to 203 pediatric and general dentists treating
children. Of the 141 dentists who voluntarily completed the questionnaire, 118
were selected for this study. These professionals worked in private and public
health centers in the Santiago, Chile, metropolitan area. RESULTS AND
CONCLUSIONS: The results showed that a majority of dentists had treated a low
number (1 to 3) of cleft palate children in the previous years, using a
combination of preventive-curative and radical treatments. Although a majority
reported that there were no differences in the treatment of the cleft and
noncleft children, a majority had problems during the course of treatment. The
results suggest the need for more current information about the care of cleft
children.
PMID- 9761564
TI - Spontaneous cleft palate in a newborn gorilla (Gorilla gorilla gorilla).
AB - OBJECTIVE: We report the first case of cleft palate in a newborn male gorilla
(Gorilla gorilla gorilla). CASE HISTORY AND RESULTS: The full-term infant was
born to clinically healthy, wild-caught parents and survived 5 days. Autopsy
disclosed a unilateral cleft palate, moderate scalp hemorrhage (birth versus
postnatal trauma), cerebral edema, and a sterile fibrin vegetation in the heart.
The palate was also shorter and narrower than expected, and the biorbital breadth
was reduced; otherwise, growth and development appeared normal. Standard cranial
and intraoral radiographs and three-dimensional reconstructions of computerized
tomographic (CT) scans provided thorough and noninvasive methods of studying the
craniofacial complex and extracranial skeleton. By this technique, major findings
were: intact premaxilla, interpremaxillary, and premaxillary/maxillary sutures;
intramaxillary cleft with ipsilateral choanal atresia; mildly asymmetric inferior
turbinates; and normal nasal septum and vomer. CONCLUSIONS: Except for choanal
atresia, cleft palate was not associated with other major craniofacial or
extracranial anomalies in this case. Choanal atresia has been observed at times
with cleft palate, but to our knowledge, the association has not been reported in
nonhuman primates. Cleft palate, with or without cleft lip, has been recognized
in a variety of nonhuman primates, including the lemur, marmoset, tamarin,
squirrel monkey, and macaque. Some occurrences are spontaneous, while others are
syndromic and/or arise from genetic or teratogenic influences. Each mode of
presentation is poorly understood in nonhuman primates, but in this case, the
absence of relevant environmental or parental history suggests that the
occurrence was spontaneous. Anatomic studies of nonhuman primates are
particularly valuable when they involve endangered species and will hopefully
increase our understanding of the pathogenesis and etiology of congenital
disorders, as well as other relationships between nonhuman primates and humans.
PMID- 9761565
TI - A comparison of two different bone-harvesting techniques for secondary alveolar
bone grafting in patients with cleft lip and palate.
AB - OBJECTIVE: To compare the outcome of the trephine with open hip surgery for
alveolar bone grafting in cleft lip and palate surgery. DESIGN: The study was
retrospective. The radiographs were assessed blindly and on two separate
occasions 1 week apart. SETTING: University Teaching Hospital. PATIENTS,
PARTICIPANTS: In one group (group A), a trephine was used; in the other (group
B), open hip surgery was employed. Group A was comprised of 16 patients (nine
with unilateral and seven with bilateral clefts of the lip and palate) and group
B, 13 patients (eight unilateral and five bilateral). The prime entry criterion
for inclusion in the study was that the canine tooth had erupted into the graft
site. INTERVENTIONS: A long cone periapical radiograph was taken of the erupted
canine tooth in the graft site. MAIN OUTCOME MEASURE: The radiographs were graded
from type I to type IV, as described by Bergland et al. (1986a). A comparison was
also made of the eruption of the canine, postoperative morbidity, and length of
stay in hospital for each group. RESULTS: There was no statistically significant
difference in the interdental bone height (p=.61, Mann-Whitney U test). In group
A, all patients had a satisfactory clinical outcome (type I or II), and in group
B, only one patient had an unsatisfactory result (type III). The spontaneous
eruption of the canine and the number of nights spent in the hospital were also
similar for both groups. However, no patients in group A suffered postoperative
complications, whereas three patients in group B reported either a limp or
postoperative infection of the hip. CONCLUSION: Both techniques produced
satisfactory repair of the bony defect, but the open hip surgery resulted in
greater postoperative morbidity.
PMID- 9761566
TI - Salvaging the failed pharyngoplasty: intervention outcome.
AB - OBJECTIVE: This paper reports on the rates of failure of operations (pharyngeal
flap and sphincter pharyngoplasty) performed for management of velopharyngeal
dysfunction, and outcome following their revision. DESIGN: Anatomic abnormalities
associated with unacceptable vocal resonance and nasal air escape following
pharyngeal flap and sphincter pharyngoplasty were critiqued. The results of
primary pharyngeal flap were evaluated for 65 patients, and the results of
primary sphincter pharyngoplasty were evaluated for 123 patients. All patients
were treated for velopharyngeal dysfunction. The definition of surgical failure
was based on persistent hypernasality and/or nasal turbulence on perceptual
speech evaluation, and incomplete velopharyngeal closure on instrumental
evaluation, at least 3 months postoperatively. SETTING: All patients were
evaluated and managed at the Cleft Palate and Craniofacial Deformities Institute,
St. Louis Children's Hospital, a tertiary cleft care center. PATIENTS,
PARTICIPANTS: All patients had failed surgical management initially, either with
pharyngeal flap or sphincter pharyngoplasty, and all underwent repeat
preoperative and postoperative perceptual speech evaluations; real-time lateral
phonation fluoroscopy including still reference views; and flexible nasendoscopy
of the velopharynx using standard speech protocols. INTERVENTIONS: Revisional
surgery for both procedures consisted of either tightening of the sphincter
pharyngoplasty or pharyngeal flap port(s) or reinsertion of the sphincter
pharyngoplasty or pharyngeal flaps following dehiscence. MAIN OUTCOME MEASURES:
The main outcome measure was normalcy of velopharyngeal function, i.e.,
elimination of perceptual hypernasality and instrumental evidence of complete
velopharyngeal closure. The rates of pharyngeal flap failure and sphincter
pharyngoplasty failure were determined for those patients requiring surgical
revision. RESULTS: Thirteen of 65 patients (20%) who underwent primary pharyngeal
flap required revisional surgery. Of these 13 patients, eight were managed
successfully with a single revisional operation. The remaining five patients
(38%) continued to exhibit velopharyngeal dysfunction and underwent a second
revision consisting of tightening or augmentation of the lateral ports. Speech
results were satisfactory in all patients so treated; however, hyponasality with
no other airway morbidity occurred in all five. Twenty of 123 patients (16%) who
underwent primary sphincter pharyngoplasty required surgical revision. Of these
20 patients, 17 were managed successfully. For both procedures, the principal
cause of failure was partial or complete flap dehiscence. CONCLUSIONS: Rates of
primary pharyngeal flap failure are roughly equivalent to rates of primary
sphincter pharyngoplasty failure. Pharyngeal flap and sphincter pharyngoplasty
failures can be salvaged with revisional surgery, which can provide a
velopharyngeal mechanism capable of complete closure. Revisional surgery is
usually associated with denasal speech.
PMID- 9761568
TI - Transmission of mutans streptococci between mothers and children with cleft lip
and/or palate.
AB - OBJECTIVE: The aim of this study was to investigate the transmission of
Streptococcus mutans between children with cleft lip and/or palate and their
mothers. DESIGN: Saliva samples of 21 mother-child pairs were collected and
cultured on plates containing a selective growth medium for mutans streptocci. At
least five separate colonies of each colony morphotype were isolated. A
polymerase chain reaction (PCR) with randomly chosen primers was used to type the
isolates. RESULTS: The number of morphotypes and PCR types was significantly
lower in the children than in the mothers. Significant correlations were found
between the number of morphotypes and PCR types, in the children as well as in
the mothers. In only 38% of the mother-child pairs were the same PCR types found
in mother and child. CONCLUSIONS: This suggests that S. mutans had been
transmitted from mother to child in one-third of the population studied. No
correlations were found among the number of colony-forming units, the number of
colony-colony-morphotypes, and the number of PCR types of the mothers and
transmission. Similar PCR types in mother and child were found significantly more
often in children who had more than one PCR type. The results indicate that
transmission of S. mutans from mother to child is not frequent in children with
oral cleft. This may have consequences for preventive treatment of cleft lip
and/or palate children and their mothers.
PMID- 9761567
TI - Branchio-oculo-facial syndrome with cleft lip and bilateral dermal thymus.
AB - OBJECTIVE: The objective of this study was to demonstrate that the branchiooculo
facial (BOF) syndrome is a cervicocephalic neural crest maldevelopment. RESULTS:
Using an embryologic study, we linked the clinical features and the level of the
neural crest deficiency. We report here two cases of BOF syndrome with a
particular branchial cleft presenting as bilateral supernumerary thymus glands on
the surface of the skin; one of the cases was associated with tetralogy of
Fallot. One patient underwent lip reconstruction at 4 months, combined with
excision of bilateral auricular pits and superior labial fistula. The other
patient had a surgical correction of the tetralogy of Fallot, and at 2 months,
the two stages of the lip reconstruction were performed, combined with bilateral
auricular pit excision. Both patients have shown normal developmental patterns to
date. CONCLUSION: The BOF syndrome must be considered as a neurocristopathy at
different levels, with a tiny mesencephalo-prosencephalic lesion and a severe
rhombencephalic lesion that includes seven consecutive hindbrain segments, from
rhombomere 2 to rhombomere 8.
PMID- 9761569
TI - Dilatation of the infrarenal aneurysm neck after endovascular exclusion of
abdominal aortic aneurysm.
AB - PURPOSE: To determine the fate of the infrarenal aneurysm neck and suprarenal
aorta after endovascular exclusion of abdominal aortic aneurysms (AAAs). METHODS:
Thirty-four patients underwent endovascular AAA repair between January 1994 and
December 1995 using custom-made stent-grafts constructed from polyester graft
material and modified self-expanding Gianturco Z-stents sutured to the graft
orifices. Thirty-one patients were available for follow-up. Pre- and
postimplantation diameters were measured using spiral computed tomography in the
infrarenal aneurysm neck and the suprarenal aorta at the level of the superior
mesenteric artery (SMA). RESULTS: The mean follow-up time was 25 months. There
was a significant increase of the diameter of the infrarenal aneurysm neck (+
1.65 mm, p = 0.002), but not in the aorta at the level of the SMA (+0.52 mm, p =
0.100). There was no difference in the change in diameter in the infrarenal neck
in the group with a stent adjacent to the level of measurement (n = 20) compared
with the group without an adjacent stent (n = 11, p = 0.790). There was no
correlation between preimplantation size of the infrarenal neck and its diameter
change (r = 0.14, p = 0.488). There was no correlation (r = 0.10, p = 0.603) or
association (chi-square test, p = 0.211) between aortic diameter change at the
level of the SMA and the infrarenal neck. CONCLUSIONS: This investigation shows a
significant dilatation of the infrarenal aneurysm neck, but not in the suprarenal
aorta, after endovascular AAA repair with this device. The clinical significance
of these findings is unclear. Whether such a dilatation in the infrarenal
aneurysm neck may affect the long-term attachment of stent-grafts remains to be
shown in the future.
PMID- 9761570
TI - Changes in referral practice, workload, and operative mortality after
establishment of an endovascular abdominal aortic aneurysm program.
AB - PURPOSE: To determine the change in referral practice following establishment of
an endovascular abdominal aortic aneurysm (AAA) program. METHODS: A prospective
audit of all elective admissions for AAA was established in January 1994 at the
initiation of an endovascular AAA program. A comparison was made between this
cohort and the elective AAA repairs performed between 1981 and 1993. RESULTS:
Since January 1994, 213 AAA patients (177 men; median age 73 years, range 54 to
88) have been referred for potential endovascular aneurysm repair. To date, 142
patients have undergone elective surgery (41 endovascular and 101 conventional).
Between 1981 and 1993, 304 patients (255 men; median age 69 years, range 45 to
86) had elective aneurysm repair. Comparison of the two time periods has revealed
significant increases in the number of tertiary referrals (41.8% versus 9.5%, p <
0.01), annual operations (50 versus 23, p < 0.05), and overall mortality (12%
versus 6.7%, p < 0.05), the latter attended by a significant increase in
cardiorespiratory comorbidity. CONCLUSIONS: The higher elective AAA mortality
rate since the establishment of an endovascular program reflects a change in
referral practice and may be directly attributable to an increase in the number
of high-risk patients. An endovascular AAA program has clinical and financial
implications for the hospital concerned.
PMID- 9761571
TI - Experience with the Stentor endograft at four Italian centers.
AB - PURPOSE: To report the outcome of an Italian multicenter trial of endovascular
abdominal aortic aneurysm (AAA) exclusion using the Stentor device. METHODS:
Between April 1995 and July 1996, 66 patients (63 men; average age 69 years,
range 53 to 84) with infrarenal AAAs meeting the inclusion criteria were
enrolled. The average diameter of the aneurysm was 4.6 cm (range 4.2 to 7). Three
(4.5%) of the 66 AAAs were anastomotic aneurysms. RESULTS: Sixteen (25%) tubular
and 50 (76%) bifurcated endograft procedures were attempted; 4 (6.1%) were
converted and 1 terminated owing to technical faults with the bifurcated graft's
second limb. One tube graft was too short and failed to exclude an anastomotic
aneurysm. Sixty (91%) endograft procedures were completed successfully. Six
(9.1%) vascular complications occurred, three in one patient who subsequently
died of pulmonary embolism 72 hours postoperatively (1.5% mortality). There were
four (6.1%) proximal endoleaks; two sealed spontaneously in < 1 month, and a
third was converted (7.6% conversion rate). The fourth is being observed.
Clinical success (aneurysm exclusion with no death or endoleak) at 30 days was
86.3% (57/66). In the 23-month follow-up of 57 eligible patients, 2 patients died
of unrelated causes and 1 graft limb thrombosed, requiring a crossover femoral
bypass. One patient was converted to surgical repair at 5 months postoperatively
when increasing aneurysm size signaled an undisclosed endoleak (1.8% late
conversion rate). Five other secondary endoleaks were treated with endovascular
techniques. CONCLUSIONS: The Stentor was technically feasible in 10% to 40% of
AAA candidates in this study, although deployment of the second limb was
problematic in the bifurcated device. Introduction of the second-generation
Vanguard endograft brought this study to an end.
PMID- 9761573
TI - Spiral CT angiography versus aortography in the assessment of aortoiliac length
in patients undergoing endovascular abdominal aortic aneurysm repair.
AB - PURPOSE: To compare measurements of aortoiliac length obtained with spiral
computed tomographic angiography (CTA) and aortography in patients undergoing
endovascular aneurysm repair. METHODS: The distances from the lower-most renal
artery to the aortic bifurcation and from the aortic bifurcation to the common
iliac artery (CIA) bifurcation were measured using both CTA and aortography in
108 patients with abdominal aortic aneurysms. RESULTS: The level of agreement
between CTA and aortography was high, with 69% of aortic and 76% of iliac
measurements within 1 cm and > 90% within 2 cm of each other. Mean differences
were -0.35 +/- 1.20 cm and 0.25 +/- 1.10 cm, respectively, for aortic and iliac
lengths. Aortography overestimated renal artery to aortic bifurcation length in
comparison to CTA (p = 0.003), particularly in patients with large aneurysms (>
6.5 cm) and lumen diameters > 4.5 cm (p < 0.0001). Measurements of CIA length
were shorter by aortography than CTA (p = 0.02). CONCLUSIONS: There is a high
level of agreement between CTA and aortography in the measurement of aortoiliac
length, but aortography overestimates renal artery to aortic bifurcation length
in patients with large-diameter aneurysms and wide aneurysm lumens. CTA is
sufficiently accurate in the majority of cases to be used as the sole basis for
the construction of endovascular grafts.
PMID- 9761572
TI - Torsion and kinking of unsupported aortic endografts: treatment by endovascular
intervention.
AB - PURPOSE: To describe the management strategies used to deal with twisted aortic
endografts. METHODS AND RESULTS: Two patients with successfully excluded aortic
aneurysms developed symptoms referable to previously undetected twists in their
endografts (one EndoVascular Technologies [EVT] and one customized aortomonoiliac
device). The limb graft occlusion in the EVT graft was treated surgically with a
femorofemoral bypass, but the aortomonoiliac endograft was salvaged with
percutaneous implantation of a Wallstent. During another aortomonoiliac
procedure, suboptimal flow through the endograft was traced to contortion of the
endograft as it passed over an angulated proximal aneurysm neck. An X-large
Palmaz stent was deployed to support the graft at this point. CONCLUSIONS:
Unsupported aortic endografts may develop twists and kinks during deployment that
can lead to low outflow and graft occlusion. Endovascular techniques are
available to repair these defects postoperatively, although more precise
intraoperative assessment tools may identify these problems so that they can be
corrected at the initial intervention.
PMID- 9761574
TI - Percutaneous endoluminal treatment of iliac occlusions: long-term follow-up in
105 patients.
AB - PURPOSE: To evaluate the long-term results of percutaneous recanalization
techniques in occluded iliac arteries. METHODS: Percutaneous recanalization was
attempted in 105 patients (97 men; mean age 56 years, range 34 to 80) with iliac
occlusions using thrombolysis (n = 15), excimer laser (n = 4), mechanical
thrombectomy (n = 16), balloon angioplasty alone (n = 23), and angioplasty plus
stenting (n = 69). The majority of lesions (n = 72) were in the common iliac
artery (CIA); 33 were in the external iliac artery (EIA). RESULTS: The primary
recanalization rate was 88% (92/105) independent of location (EIA: 90%, CIA: 86%)
and lesion length, but dependent on age of thrombus (< 3 months: 100%, > 3
months: 79%, p < 0.02). Complications included 5 (4.8%) cases of distal embolism
treated by thromboaspiration or Fogarty balloon embolectomy. Seven (6.7%) early
thromboses were treated surgically. Primary and secondary patency rates were
calculated at 6 years for all 105 cases and for the 92 recanalized lesions using
life-table analysis. Overall, primary patency was 52% (CIA: 58%, EIA: 34%) and
secondary 66% (CIA: 74%, EIA: 40%). Lesions < 6 cm had a primary patency of 70%,
while those > 6 cm had a 31% rate (p < 0.01). Secondary patencies were 86% and
42%, respectively (p < 0.01). Among recanalized lesions, the primary patency was
61% (CIA: 69%, EIA: 38%) and secondary 77% (CIA: 88%, EIA: 45%; p < 0.05).
Lesions < 6 cm had a primary patency rate of 72%, while longer lesions had a
primary rate of 44% (p < 0.04); secondary patencies were 89% and 59%,
respectively (NS). Primary patency without stent was 57% and with stent 65% (NS);
secondary patency without stent was 71% and with stent 82% (NS). CONCLUSIONS:
Percutaneous recanalization of iliac occlusions represents a true alternative to
vascular surgery and a first-line treatment option. Stents have a tendency to
improve long-term results and are recommended for routine use in chronic iliac
occlusions.
PMID- 9761575
TI - Outpatient endovascular intervention: is it safe?
AB - PURPOSE: To evaluate the feasibility and safety of outpatient percutaneous
endovascular intervention in the treatment of arterial occlusive disease.
METHODS: The records of 134 patients who underwent 151 outpatient endovascular
procedures between 1992 and 1997 were reviewed retrospectively. According to
established protocol, focal lower limb (n = 145) and subclavian (n = 6) arterial
lesions requiring relatively straightforward endoluminal interventions were
appropriate for outpatient management provided the patients were free of
significant comorbidities. A percutaneous transfemoral approach was used for
lower limb lesions, while subclavian angioplasty was performed via a brachial
access. Heparin anticoagulation was administered conservatively. Patients were
discharged 3 hours after sheath removal. RESULTS: The majority (98%) of patients
were discharged as planned. Three (2%) patients were observed overnight in the
hospital for treatment of acute iliac artery thrombosis, puncture-site bleeding,
and suboptimal angioplasty. No patient required hospitalization following
discharge. Periprocedural morbidity was confined to 2 (1.5%) groin hematomas and
1 (0.7%) femoral pseudoaneurysm. CONCLUSIONS: Outpatient endovascular
intervention appears safe; however, proper case selection and technical
excellence are inseparable components for the success of this strategy.
PMID- 9761577
TI - Carotid plaque characterization: helpful to endarterectomy and endovascular
surgeons.
PMID- 9761576
TI - Carotid plaque characterization using digital image processing and its potential
in future studies of carotid endarterectomy and angioplasty.
AB - PURPOSE: To corroborate the validity of a computerized methodology for evaluating
carotid lesions at risk for stroke based on plaque echogenicity. METHODS: The
records of 96 carotid endarterectomy patients (59 men; median age 69.5 years,
range 52 to 83) with stenoses > 50% were studied retrospectively. Forty-one
patients (43%) had been symptomatic preoperatively. All patients had undergone
computed tomography (CT) to detect infarction in the carotid territory and a
duplex scan to measure carotid stenosis. Plaque echogenicity was analyzed by
computer, expressing the echodensity in terms of the gray scale median (GSM). The
incidence of CT-documented cerebral infarction was analyzed in relation to
symptomatology, percent stenosis, and echodensity. RESULTS: Symptoms correlated
well with CT evidence of brain infarction: 32% of symptomatic patients had a
positive CT scan versus 16% for asymptomatic plaques (p = 0.076). The mean GSM
value was 56 +/- 14 for plaques associated with negative CT scans and 38 +/- 13
for plaques from patients with positive scans (p < 0.0001). However, there was no
difference in the GSM value between plaques with > or < 70% stenosis.
Furthermore, the incidence of CT infarction was 40% in the cerebral territory of
carotid plaques with a GSM value < 50 and only 9% in those with a GSM > 50 (p <
0.001). CONCLUSIONS: Computerized analysis of plaque echogenicity appears to
provide clinically useful data that correlates with the incidence of cerebral
infarction and symptoms. This method of analyzing plaque echolucency could be
used as a screening tool for carotid stent studies to identify high-risk lesions
better suited to conventional surgical treatment.
PMID- 9761578
TI - Assessment of apparent vena caval penetration by the Greenfield filter.
AB - PURPOSE: To examine and elucidate the mechanisms for apparent "penetration" by
Greenfield vena caval filters. METHODS: Two filters were placed in the inferior
venae cavae (IVC) of four immature sheep and followed with cavography for 1 year.
Two animals underwent computed tomography (CT) and laparoscopic examination. At
necropsy, the vena cava and adjacent structures of all four animals were examined
grossly and histologically. RESULTS: Based upon cavography and CT imaging, all
filters appeared to penetrate the vena cava at 12 months. However, at
laparoscopy, no hooks or limbs were exposed, and the pericaval tissues remained
intact; each hook or limb was within the adventitia or encapsulated in scar
tissue. Histology of the tissue at the hook sites revealed remodeling of the
intimal surface of the IVC and thinning of the adventitia. CONCLUSIONS: Based
upon these data, we hypothesize that the vena cava gradually adapts by medial and
adventitial thinning and myointimal remodeling to the radial force exerted by a
filter. This process allows increase in the filter base diameter while
maintaining the integrity of the cava and protecting adjacent structures.
PMID- 9761579
TI - Femoral artery exposure for endovascular aneurysm repair through oblique
incisions.
AB - PURPOSE: To offer an alternative technique for accessing the femoral artery prior
to endovascular grafting. TECHNIQUE: An oblique incision is made over the medial
half of the inguinal ligament and continues to the femoral sheath, which is
opened longitudinally. The distal external iliac artery and proximal common
femoral artery are isolated. A tiny stab wound is made distal to the primary
wound for femoral artery puncture and catheter access. CONCLUSIONS: Using an
oblique incision at the level of the inguinal ligament optimizes exposure for
endograft insertion and may minimize the frequency of serious wound
complications.
PMID- 9761580
TI - A method for adjusting a malpositioned bifurcated aortic endograft.
AB - PURPOSE: To report the successful application of a method to adjust a
malpositioned bifurcated stent-graft after endovascular aortic aneurysm repair.
METHOD AND RESULTS: A 62-year-old male patient underwent endovascular repair of a
5.1-cm abdominal aortic aneurysm (AAA) with a Vanguard bifurcated stent-graft.
After complete deployment of the stent-graft, the intraoperative completion
angiogram disclosed unexpected occlusion of the left renal artery. Intra-aortic
adjustment of the bifurcated graft was possible with a crossover guidewire, which
was pulled caudally. The method worked perfectly to restore blood flow to the
left renal artery. The patient is well 16 months postoperatively without any
evidence of endoleak or graft migration; the left renal artery remains open.
CONCLUSIONS: A technique is demonstrated for intra-aortic repositioning of a
bifurcated stentgraft to correct insufficient deployment. If required, this
technique should be attempted before conversion to an open procedure.
PMID- 9761581
TI - Troubleshooting maldeployed aortic endografts.
PMID- 9761582
TI - Aortoenteric fistula caused by a ruptured stent-graft: a case report.
AB - PURPOSE: To report a case of aortoenteric fistula secondary to endovascular
abdominal aortic aneurysm (AAA) exclusion using the Stentor bifurcated
endovascular graft. METHODS AND RESULTS: Seventeen months after a successful
endovascular AAA procedure, a male patient developed upper gastrointestinal
bleeding. An aortoenteric fistula was diagnosed. At operation, the endograft
fabric was found to be ruptured in an area of suture disruption between the
nitinol stents. Coincidentally, a pre-existing inflammatory process might have
caused adhesions between the bowel and the aortic wall, predisposing to fistula
formation. The patient recovered after placement of a conventional aortic graft.
CONCLUSIONS: Suture disruption between the internal support stents is a
recognized complication in the first-generation Stentor device. Although the case
described here is probably not typical of the consequences of this sequela, it
does reinforce the need for continual periodic imaging to check for signs of
graft disruption in Stentor endografts.
PMID- 9761583
TI - Late failure of early-model endografts: a complication whose time has come?
PMID- 9761584
TI - Late aortic arch perforation by graft-anchoring stent: complication of
endovascular thoracic aneurysm exclusion.
AB - PURPOSE: To describe a fatal case of late aortic perforation by an endograft
anchoring stent. METHODS AND RESULTS: A 69-year-old woman presented 2 years after
thoracoabdominal aneurysm repair with a 9-cm dilatation of the descending
thoracic aorta proximal to the conventional aortic graft. A 38-mm Dacron graft
with multiple Gianturco Z-stents sutured inside was placed transluminally across
the aortic arch such that part of the uncovered portion of the proximal stent was
partially across the left subclavian orifice. Four months later, the patient died
from massive hemorrhage. Autopsy showed that the uncovered portion of the
proximal stent had perforated the aortic arch. CONCLUSIONS: This case stresses
the need for low-profile stent-grafts and smaller, more flexible introducer
systems. Anchoring stents must be flexible, less traumatic, and strong enough to
create a watertight seal even in tortuous vessels. To avoid aortic arch damage by
thoracic stent-grafts, the proximal stent should be fully covered by the fabric.
PMID- 9761585
TI - Endovascular repair of aortic aneurysms in the the presence of a horseshoe
kidney.
AB - PURPOSE: To report two cases of endovascular aortic aneurysm exclusion in
patients with a horseshoe kidney. METHODS AND RESULTS: Two male patients, one
with a known horseshoe kidney and history of multiple previous laparotomies,
presented with abdominal aortic aneurysms of approximately 6-cm diameter. Each
was treated with a tapered aortomonoiliac polytetrafluoroethylene graft secured
proximally with a Palmaz balloon-expandable stent. The endograft was sutured
distally to a Dacron femorofemoral crossover graft. An anomalous renal vessel was
sacrificed in one case. The aneurysms were successfully excluded, and the
patients recovered without sequelae. CONCLUSIONS: Endovascular repair should be
considered as a treatment option in patients with aortic aneurysm in the presence
of a horseshoe kidney, particularly if the renal vasculature can be wholly
preserved.
PMID- 9761586
TI - Hypercoagulability and the management of anticoagulant therapy in surgical
patients: review and recommendations.
PMID- 9761587
TI - Symposium overview: the use of delayed matching-to-sample procedures in studies
of short-term memory in animals and humans.
AB - Behavioral paradigms applicable for use in both human and nonhuman subjects for
investigating aspects of working/short-term memory are presented with a view
towards exploring their strengths, weaknesses, and utility in a variety of
experimental situations. Such procedures can be useful in teasing out specific
aspects of mnemonic processes including discrimination, encoding, and retention.
Delayed matching-to-position, delayed matching-to-sample (DMTS), and titrating
matching-to-sample procedures are highlighted. Additionally, the application of
DMTS tasks in preclinical and clinical settings is presented: drug effects on
memory processes can be explored preclinically in animal models; normative data
have been developed in human populations where they have been used in adults to
explore the relationships between mnemonic processes and specific clinical
entities such as Parkinsonism, senile dementia of the Alzheimer's type,
schizophrenia, and depression. Studies in children indicate that encoding and
retention processes improve rapidly in the early years, plateauing prior to
puberty. Noninvasive imaging techniques such as positron emission tomography
(PET) indicate that activity in specific brain areas is associated with DMTS task
performance and may serve to confirm roles for such structures in mnemonic
processes.
PMID- 9761588
TI - Comparison of the behavior of the curly tail and CBA mouse on a neurologic scale.
AB - ct/ct mice are a mutation of the CBA strain with a high incidence of spina bifida
(SB). Because humans with SB can exhibit abnormal behavior, we compared ct/ct and
CBA mice using a neurologic assessment tool. ct/ct mice are more active and
engage in more climbing, and stereotypical and compulsive behavior. When
stimulated during cage removal ct/ct mice react more vigorously. ct/ct mice react
more vigorously to a novel stimulus, and will vigorously search for a stable
surface during visual placement. In the open field ct/ct mice crossed more lines
and reared more than CBA. ct/ct mice demonstrated deficient performance in a
modified Morris water maze. No differences were noted for other behaviors tested.
The results argue that the mutation that produces SB in ct/ct mice also alters
brain structure or chemistry. This is consistent with the findings in humans
where SB can produce a variety of behavioral anomalies, most notably
hyperactivity, attentional disorders, learning disabilities, and developmental
lags.
PMID- 9761589
TI - Cognitive and sensorimotor functions in 6-year-old children in relation to lead
and mercury levels: adjustment for intelligence and contrast sensitivity in
computerized testing.
AB - Within a larger environmental health screening program neurobehavioral measures
were taken in 384 6-year-old children (mean age 74 months) in the cities of
Leipzig, Gardelegen, and Duisburg. Lead concentrations in venous blood samples
(PbB) and urinary mercury excretion in 24-h samples (HgU) were measured as
markers of environmental exposure by electrothermal AAS. Dependent variables
included two subtests from the WISC [vocabulary (V) and block design (BD)] as
well as five tests from the NES2 [pattern comparison, pattern memory, tapping,
simple reaction time, and the continuous performance test (CPT; child version)].
In addition, visual functions [visual acuity (TITMUS-test) and contrast
sensitivity (FACT)] were tested as covariates. The overall average PbB (geometric
mean) was 42.5 microg/l (upper 95% value = 89 microg/l). The overall average
mercury excretion (HgU) was 0.16 microg/24 h. Whereas no significant or
borderline associations between HgU and any of the target variables was found,
significant negative associations were observed between PbB and verbal
intelligence (WISC vocabulary but not WISC Block Design) and false-positive
responses (false alarms), as well as false-negative responses (miss) in the CPT.
Whereas parental education was the most important confounder for WISC
performance, visual contrast sensitivity and computer familiarity also proved
predictive for performance in several computer-based NES subtests. It is
concluded that non-IQ measures, namely measures of sustained attention, are
negatively affected in children with 95% of blood-lead levels below 90 microg/l,
even after adjustment for intelligence and contrast sensitivity, whereas the
causative role of lead in altering IQ functions remains somewhat equivocal,
because important covariates could not be controlled for.
PMID- 9761590
TI - Ethanol inhibition of brain ornithine decarboxylase activity in the postnatal
rat.
AB - The purpose of this study was to determine the relationship between ornithine
decarboxylase activity (ODC; a marker for perturbed cell development), the blood
alcohol level, and alcohol-induced microencephaly in the developing rat brain
after binge treatment with ethanol vapour. By manipulating ethanol flow we were
able to adjust vapour concentrations (24-65 mg ethanol/l air) such that an acute
exposure of ethanol vapour for 3 h resulted in a range of blood alcohol levels
(2.3-5.5 mg/ml). Acute studies showed that ethanol dose-dependently inhibited rat
hippocampal and cerebellar ODC activity at PND4-PND10. There was a significant
correlation between the blood alcohol level and degree of inhibition at all ages
tested. Chronic treatment from PND4 to PND9 caused a significant decrease in both
brain to body weight ratio and in hippocampal and cerebellar ODC activities at
PND10. These results indicate that ethanol-induced disruption in ODC could play a
significant role in ethanol's teratogenic effects during early postnatal
development.
PMID- 9761591
TI - Enhancement of cocaine-induced hyperthermia fails to elicit neurotoxicity.
AB - The neurotoxic potential of cocaine when administered under conditions conducive
to the initiation of hyperthermia was investigated. Rats were administered
cocaine at ambient temperatures of 22 degrees C or 30 degrees C. To determine the
thermal response, body temperatures were measured every 30 min and the total
thermal response (TTR), representing the area under the temperature vs. time
curve, was calculated. Saline administered at 22 degrees C or 30 degrees C
resulted in a normal thermal response (TTR = 9.8+/-0.9 and 11.2+/-0.9,
respectively). Cocaine administration resulted in ambient temperature-dependent
hyperthermia. Cocaine (4 x 25 mg/kg) administered at 22 degrees C resulted in a
TTR of 15.1+/-0.9 whereas cocaine (4 x 15 or 25 mg/kg) administered at 30 degrees
C resulted in TTRs of 22.2+/-0.9 and 21.9+/-0.8, respectively. Regardless of the
dose or thermal response, cocaine administration did not result in depletion of
dopamine (DA) or serotonin (5-HT) in the caudate-putamen. Cocaine administration
also failed to induce an increase in the concentration of glial fibrillary acidic
protein (GFAP), a marker for neurotoxicity. These results demonstrate that
hyperthermia does not promote cocaine-induced neurotoxicity in the rat caudate
putamen.
PMID- 9761592
TI - Influence of chronic fluorosis on membrane lipids in rat brain.
AB - Brain membrane lipid in rats were analyzed after being fed either 30 or 100 ppm
fluoride for 3, 5, and 7 months. The protein content of brain with fluorosis
decreased, whereas the DNA content remained stable during the entire period of
investigation. After 7 months of fluoride treatment, the total brain phospholipid
content decreased by 10% and 20% in the 30 and 100 ppm fluoride groups,
respectively. The main species of phospholipid influenced by fluorosis were
phosphatidylethanolamine, phosphatidylcholine, and phosphatidylserine. The fatty
acid and aldehyde compositions of individual phospholipid classes were unchanged.
No modifications could be detected in the amounts of cholesterol and dolichol.
After 3 months of fluoride treatment, ubiquinone contents in brain were lower;
however, at 7 months they were obviously increased in both groups of fluoride
treatment. The results demonstrate that the contents of phospholipid and
ubiquinone are modified in brains affected by chronic fluorosis and these changes
of membrane lipids could be involved in the pathogenesis of this disease.
PMID- 9761593
TI - Prenatal sulfur dioxide exposure induces changes in the behavior of adult male
mice during agonistic encounters.
AB - Sulfur dioxide (SO2) is one of the most important pollutants of the western
countries, responsible for several cardiopulmonary diseases in humans. SO2
affects both young and adult people, causing low work productivity with social
and economical costs extremely high for the communities. To test whether or not
SO2 produces changes in social and/or agonistic behavior of laboratory animals,
outbred CD-1 male mice were prenatally exposed to different SO2 concentrations
(0, 5, 12, or 30 ppm) up to pregnancy day 14. At adulthood, following a 4-week
isolation period, they underwent an aggressive encounter with CD-1 male opponents
of the same age, body weight, and isolation condition (single 20-min session).
The levels of several responses such as tail rattling, freezing, and defensive
postures were reduced by the treatment, particularly during the initial period of
the agonistic encounter, whereas offensive and attack behaviors were not
significantly modified. In addition, rearing and social investigation increased.
Overall, the present results indicate that prenatal SO2 exposure can alter mouse
social/agonistic behavior, apparently acting on the approach phase toward the
opponent and suggestive of changes in the animals' capability to cope with
threatening dangerous situations.
PMID- 9761594
TI - Perinatal delta9-tetrahydrocannabinol exposure did not alter dopamine transporter
and tyrosine hydroxylase mRNA levels in midbrain dopaminergic neurons of adult
male and female rats.
AB - We have recently demonstrated that the magnitude of L-3,4-dihydroxyphenylacetic
acid (DOPAC) lowering effect caused by amphetamine in midbrain dopaminergic
neurons of adult rats was lesser in animals that had been perinatally exposed to
delta9-tetrahydrocannabinol (delta9-THC) than controls. In the present study, we
have examined whether this loss in the responsiveness to amphetamine might be due
to changes at the level of dopamine transporter (DAT), the main molecular site
for the action of amphetamine, following the perinatal exposure to delta9-THC. To
this end, we have analyzed DAT mRNA levels, by using in situ hybridization, in
the substantia nigra and ventral tegmental area, the areas where cell bodies of
DAT-containing midbrain neurons are located, of adult male and female rats that
had been perinatally exposed to delta9-THC. In addition, we also analyzed mRNA
levels of tyrosine hydroxylase (TH), the rate-limiting enzyme in DA synthesis.
Results were as follows. Both adult male and female rats that had been
perinatally exposed to delta9-THC exhibited similar mRNA levels to controls for
both DAT and TH in the substantia nigra as well as in the ventral tegmental area.
This observation makes it difficult to support the idea that the differences
found in adulthood after pharmacological challenges were caused by irreversible
changes at the level of gene expression for these two key proteins.
PMID- 9761595
TI - Long-term effects of early cocaine exposure on the light responsiveness of the
adult circadian timing system.
AB - Early cocaine exposure is associated with a wide variety of neurobehavioral and
teratogenic effects. The current study was conducted to determine the long-term
effects of such exposure on the hamster circadian timing system. The circadian
system drives rhythms in a tremendous diversity of physiological, behavioral, and
endocrine functions. The fetal circadian pacemaker has recently been shown to
express a functional D1 dopamine system that is involved in maternal-fetal
entrainment. Maternally administered cocaine, acting on the fetal clock, could
therefore potentially have long-lasting effects on exposed offspring. Pregnant
SCN-lesioned hamsters or their pups, maintained in constant dim illumination
(DD), were administered cocaine (30 mg/kg, SC, N = 10 litters) or saline vehicle
(N = 5 litters) from embryonic (E) day 15 [day of mating = E0] through postnatal
(P) day 5. Upon weaning (P21), cocaine- and saline-treated offspring were placed
in individual running wheels for a period of 5-6 weeks. Individuals were then
challenged with 1-h light pulses at three circadian times (CT7, CT14, CT18).
Cocaine-treated litters had a statistically significant mean phase advance of
+0.32 h at CT14 compared with the mean phase delay of 2.13 h of the saline
treated litters. No significant differences were seen at the other two circadian
times, although there was heterogeneity in the responses among cocaine-treated
animals. This represents the first demonstration of an effect of perinatal
cocaine on the circadian timing system. Together with the recent demonstration of
D1 receptors in the human SCN, these findings raise the possibility that
gestational cocaine abuse by humans may also lead to later disturbances in the
circadian timing system.
PMID- 9761596
TI - Alcohol-induced inhibition of cocaine metabolism and the formation of
cocaethylene in neonatal rats.
AB - Due to the significant species differences in the timing of different stages of
brain development, to study the effects of drugs during the period equivalent to
the third trimester in humans it is necessary to administer the drugs to neonatal
rats. rather than in utero. In this study, we investigated the pharmacokinetic
interactions between alcohol and cocaine. Such information is critical in
understanding the roles of alcohol and cocaine in mediating neuroteratogenesis.
Sprague-Dawley rat pups (10 days old) were given IP injections of alcohol (3.3 or
5.0 g/kg) and/or cocaine (40 mg/kg). At 20, 60, or 100 min (60 and 100 min for
3.3 g/kg alcohol only) after injections, 20 microl of tail blood was collected
for blood alcohol concentration (BAC) determination. Immediately after tail blood
collection, blood was collected and pooled for determinations of blood cocaine
(BCC), benzoylecgonine (BBC), and cocaethylene concentration (BCEC). The slopes
of the ascending BAC curves were unaffected in the presence of cocaine. BCC
levels declined significantly as a function of time after the peak level at 20
min postinjection time. BCC levels were unchanged in pups receiving 3.3 g/kg
alcohol, but the levels were significantly higher in 5.0 g/kg pups 20 min after
injections. BBC concentrations were reduced to nearly 50% in the presence of
alcohol (both doses) 20 min after injections. BCEC was detected at all time
points when both alcohol and cocaine were injected. Taken together, these
findings indicated that the enzymatic systems involved in converting cocaine to
cocaethylene were functional at an early postnatal age, and the metabolism of
cocaine was affected by the presence of alcohol in neonatal rats.
PMID- 9761598
TI - Editorial
PMID- 9761597
TI - Proglumide, a cholecystokinin receptor antagonist, exacerbates beta, beta'
iminodipropionitrile-induced dyskinetic syndrome in rats.
AB - The present investigation was undertaken to study the effect of proglumide, a
cholecystokinin (CCK) receptor antagonist, on iminodipropionitrile (IDPN)-induced
excitation, chorea, and circling (ECC) syndrome in rats. The animals were exposed
to IDPN in the dose of 100 mg/kg/day IP for 9 days. Proglumide (PG) was
administered IP daily 1 h before IDPN in the doses of 250, 500, and 750 mg/kg
body weight in three different groups of rats. The animals were observed daily
for neurobehavioral abnormalities including dyskinetic head movements, circling,
tail hanging, air righting reflex, locomotor activity, and contact inhibition of
the righting reflex. After behavioral studies, blood and brain samples were
collected for the analysis of malondialdehyde (MDA), conjugated dienes, vitamin
E, and glutathione peroxidase (GSH-Px). The temporal bones were also collected
for inner ear histopathology. Our results showed that proglumide significantly
and dose-dependently exacerbated the incidence and the severity of IDPN-induced
ECC syndrome during the treatment period as well as up to 3 weeks of postdosing.
Administration of IDPN produced a significant increase in MDA and conjugated
dienes and a decrease in vitamin E and GSH-Px, suggesting the role of oxygen
derived free radicals (ODFR) in IDPN-induced neurotoxicity. Concomitant treatment
with proglumide potentiated IDPN-induced oxidative stress. The histopathology of
the inner ear showed significantly high degeneration of sensory hair cells in the
crista ampullaris of the rats treated with IDPN plus proglumide compared to IDPN
alone-treated animals. Further studies are warranted to determine the role of CCK
in nitrile toxicity and drug-induced dyskinesia.
PMID- 9761599
TI - [Isolation of Vibrio cholerae O1 from aquatic environments and foods in
Pernambuco State, Brazil].
AB - Incidence of Vibrio cholerae O1 was studied in 2,585 samples from different
aquatic environments and 91 from foods in Pernambuco State, northeastern Brazil,
from 1992 to 1994. A total of 193 (7.21%) samples of V. cholerae were isolated
with a higher prevalence of the Inaba serovar (183-94.8%) than the Ogawa serotype
(10-5.1%). All isolates were classified as biotype El Tor, and resistance
patterns to antibiotics showed that all strains were susceptible tetracycline.
Some 70 random samples of Vibrio cholerae proved toxigenic, including all the
Ogawa serovars. Incidence of V. cholerae O1 in river water and sewage (86.0%)
pointed to fecal contamination as the most common source and vehicle for rapid
spread of the microorganism in the aquatic environment. The vibrio was isolated
in 2.1% of all food examined, which was less than expected.
PMID- 9761600
TI - [Air pollution and living conditions: a geographical analysis of health risk in
Volta Redonda, Rio de Janeiro, Brazil].
AB - Air pollution is a widely recognized hazard to human health. In industrial cities
the emission of toxic gases and particulate matter into the atmosphere compounds
the pollution problem caused by circulation of vehicles, often creating hazardous
public health situations. The goal of this study was to analyze patterns in
pollution and living conditions in Volta Redonda and identify more vulnerable
areas and population groups. Volta Redonda is a city near Rio de Janeiro with
250,000 inhabitants and Brazil's main steel industrial complex. The presence of
several factories in the city, especially the huge CSN steel plant, contributes
to increased air pollution levels, to the point that this city is one of the most
heavily polluted in the country. The methodology applied to identify areas and
groups of people most vulnerable to this sort of pollution utilized a GIS
software. The study showed that the northwestern area of Volta Redonda had the
worst environmental and living conditions.
PMID- 9761601
TI - [Prenatal care in Pelotas, Rio Grande do Sul, Brazil, 1993].
AB - All 5304 births in the hospitals of Pelotas, Rio Grande do Sul, Brazil in 1993
were studied. Neonates were examined and their mothers were interviewed regarding
sociodemographic conditions, family income, reproductive health, and medical care
during pregnancy. Ninety-five per cent of women received prenatal care. The mean
number of physician visits during pregnancy was 7 and the majority of the women
(84.7%) began visits before the fifth month of pregnancy. Women who did not
receive prenatal care were from the lowest socioeconomic stratum and were mostly
adolescents or over 40 years of age. Incidence of low birth weight in this group
was 2.5 times that of the group with more than five visits (p>0.001). Perinatal
mortality rate was 50.6/1000 in the group without prenatal care and 15.8/1000 in
the group with more than five visits. With regard to utilization of health care,
the study shows that twenty-five per cent of women with high gestational risk
received inadequate prenatal care. The rate was less than 10% in the group of
women with low gestational risk. These results suggest the need for improvement
in the quality of prenatal care with special attention for mothers with high
gestational risk.
PMID- 9761602
TI - [Effects of survival bias on the prevalence of malnutrition in six-year-old
children in Brazil, based on the national survey on health and nutrition, 1989].
AB - Child growth as measured by anthropometric indicators is an important tool for
assessing children's nutritional status and society's developmental stage. This
study uses the height-for-age indicator with the cutoff point at -2 Z to estimate
prevalence of malnutrition in a population of six-year-old children included in
the Brazilian National Survey on Health and Nutrition (PNSN). Prevalence
variability was analyzed according to gender, trimestral age range, per capita
family income, and region of residence. Based on estimates of mortality rates for
children under five whose deaths could be ascribed to malnutrition, the survival
bias correction was performed using the Boerma methodology. This correction, in
turn, was more conspicuous within the low-income and less-developed segment of
the population. There was an increase in the number of malnourished children in
relation to those surviving at the time of investigation. When comparing less and
more developed areas of the country (the Northeast and Southeast, respectively),
we observed that malnutrition prevalence rates within the six-year-old group
showed no change in the Southeast region, while in the Northeast they increased
from 26% to 34%, thus representing a 31% increase in the malnutrition rate.
Therefore, in absolute figures, these rates account for the addition of 90,100
children to the malnourished group.
PMID- 9761603
TI - [Overpricing and affordability of drugs: the case of essential drugs in Mexico].
AB - Accessibility and availability of drugs has been a matter of great concern for
health services all over the world, especially for less developed countries. The
World Health Organization has devoted considerable time to this matter, as
evidenced in several documents and policies, such as model lists of essential
drugs and the strategy "Health for All by the Year 2000". The WHO policy for
essential drugs has been widely accepted, and the WHO List of Essential Drugs is
now in the ninth revised edition. Although the essential drug policy has been
well-accepted by health agencies and NGOs, the pharmaceutical industry has not
proven willing to produce essential drugs at affordable prices. The purpose of
this study is to examine price levels of essential drugs in Mexico. The
evaluation was performed through a comparison of international and national
prices for leading drugs in the respective therapeutic categories and included in
the WHO model list of essential drugs. The study shows clearly that prices of
essential brand-name drugs in Mexico are very high. Per capita consumption has
remained stable despite a sharp decrease in the Mexican GDP since 1995. The
article discusses the reasons for this and proposes measures to deal with the
problem.
PMID- 9761604
TI - [Intestinal parasitism in a Parakana indigenous community in southwestern Para
State, Brazil].
AB - To determine the occurrence and epidemiological aspects of intestinal parasites
among the Parakana indigenous people in the Paranatinga settlement (in the
eastern Amazon Region), parasitological tests were performed in April 1992 and
February 1995. One fresh stool specimen was obtained and immediately processed
using the Hoffman and direct methods. Some 126 samples were obtained in April
1992 (from a total population of 215 individuals). Some 80. 2% (101) of those
tested were infected with at least one species of intestinal parasite. Hookworms
were found in 33.3%, Ascaris lumbricoides 42.8%, Trichuris trichiura 0.8%, and
Strongyloides stercoralis 5.6%. Entamoeba histolytica and Giardia lamblia
protozoans were found in 65.0% and 46.8% of those tested, respectively. A second
parasitological survey was performed on 174 individuals (from a population of
253) in February 1995. 88.5% were infected. Note that prevalence in February 1995
was higher than in April 1992 (p=0.04). It was lower for hookworms, E.
histolytica, and G. lamblia, with no S. stercoralis (p<0.05). Despite provision
of health care in the Paranatinga community, prevalence of intestinal parasites
is still extremely high, suggesting that primary and secondary health care should
be increased immediately to increase the efficacy of prevention of intestinal
parasites.
PMID- 9761605
TI - [The national health system and health policies in the Brazilian dentistry
literature, 1986-1993].
AB - The Brazilian scientific literature on social and preventive dentistry from 1986
to 1993 was identified and analyzed to verify whether themes of papers referred
to health policy and the national health system. Published scientific articles
were used as the unit of analysis for the study. An analytical survey was
conducted considering the following variables, amongst others: author's
institutional affiliation; author's title; author's areas of interest; type of
research; type of article; and research funding sources. Articles reviewed were
published between the First and Second National Oral Health Conferences. There
were 386 articles published in 19 journals, by at least 866 authors. More than
75% of the studies came from public universities. RGO was the largest publisher
in this field, followed by Revista da APCD. Original articles accounted for 56.7%
of the studies, while 30.3% were reviews and essays. The majority of the authors
were from the State of Sao Paulo. Male writers predominated. A 'quantitative
deficiency' was identified, since scientific production remained below 50% of its
potential. Health policy was considered a specific issue in only 3 articles
(0.8%) while 7 (1.8%) discussed the national health system.
PMID- 9761606
TI - Caffeine intake and pregnancy outcomes: a meta-analytic review.
AB - Epidemiological publications on the relationship of caffeine to birth weight and
duration of human pregnancy, from 1966 to 1995, were searched through Medline.
Each study was treated as the stratification variable, and its weight average was
proportional to the inverse of its variance. Twenty-six studies were located.
Among the twenty-two studies on birth weight, eleven were on mean birth weight,
nine on low birth weight (LBW), and four on intrauterine growth retardation
(IUGR). Combined analysis of mean birth weight study results showed a significant
decrease in birth weight of nearly 43g among newborns of the heaviest caffeine
consuming mothers. LBW, IUGR, and preterm delivery displayed significant
homogeneity in the test results, indicating that a pooled estimate should not be
taken as na adequate measure. The high heterogeneity of the available literature
on the effects of caffeine on LBW, IUGR, and preterm delivery prevents estimation
of reliable pooled estimates through meta-analysis. Further assessment of
caffeine intake during pregnancy is needed in future research.
PMID- 9761608
TI - [Policy and collective health: a reflection on scientific production (1976
1992)].
AB - This study systematizes the theoretical and conceptual foundations in the field
of Collective Health that have provided the basis for scientific production in
the health policy area. The primary research source is the literature produced in
two different contexts in this field, i.e., that of its emergence per se and the
scope of the so-called Health Reform. The authors highlight the main concepts and
theoretical references from the social sciences used in analyzing the health
policy theme, identifying analytical distinctions, concepts pertaining to policy,
the state, and health, and changes in the central categories from the various
studies. Their analysis of this history indicates a reshaping of the theoretical
frame of reference, giving greater flexibility to the structural determinism and
macrosocial approach characterizing a major portion of academic production in the
context from which the field emerged and thereby questioning the hegemony of the
Marxist paradigm. In relation to more recent production, the authors emphasize
the incorporation of new analytical references, thus providing greater complexity
to the relationship between the social sciences and the field of Collective
Health.
PMID- 9761607
TI - [Poverty, demographic growth, and birth control: a critique of Peter Singer s
ethical perspective on the relationship between rich and poor].
AB - This article analyzes the relationship between population growth and ethical
principles relating to poverty. The paper is a critical approach to the thesis
presented by Peter Singer in his book Practical Ethics. The first part briefly
examines the principal topics of his thesis. The author then analyzes the basis
of Singer's theory with respect to the following questions: 1. Is overpopulation
the main reason for poverty? Is it possible to establish an association between
the poverty phenomenon and population growth? 2. Is Singer s demographic
perspective valid? 3. Can problems of resource distribution be ignored when
talking about poverty from an ethical perspective? 4. Is it true that birth
control policy was successfully implemented in Mexico, Colombia, and Brazil? 5.
Does Singer s position on population growth have a negative influence on the
"collective imagination"? The paper concludes by suggesting some useful arguments
for understanding an ethical perspective towards poverty.
PMID- 9761609
TI - [Methodological issues in epidemiological studies of repetitive strain injuries].
AB - Repetitive strain injuries (RSI) are a major public health problem with social
and economic repercussions. This article presents a critical review of the
published literature on RSI. The vast majority of the studies conducted in the
last two decades were cross-sectional and exploratory. Results are difficult to
interpret due to such methodological problems as lack of standardization and
accuracy in identification of cases, inclusion of cases with potentially
different diseases, varying levels of severity in the same study, lack of
distinction between prevalent and incident cases, lack of precision in the
definition and measurement of exposure, and confounding, besides the built-in
constraint of cross-sectional studies for inferring causality. Some of these
problems result from our insufficient knowledge of upper-limb soft tissue
disorders and the absence of reliable diagnostic tests. Such problems could be
addressed by studies whose design considered and stratified cases according to
certainty and specificity of diagnosis.
PMID- 9761610
TI - [Secular trends in the stature of Brazilian Navy recruits born from 1940 and
1965].
AB - The present paper reports data on secular trends in the stature of Brazilian Navy
recruits born from 1940 to 1965. The final sample included 3269 individuals aged
18.00-18.99. Statistics performed were: ANOVA (one-way and two-way), Sheffe test,
simple linear regression between stature and year of birth, and multiple linear
regression adjusting for level of schooling (beta coefficient) and chi-square.
Results indicated a progressive growth trend in stature of 0.1 cm/yr. for the
country as a whole. The trend was also observed for nearly all regions and two
out of three levels of schooling and can be explained by improvement in some of
the country's health indicators. One important characteristic was a higher level
of schooling observed among Navy recruits, suggesting that these individuals
represent a highly select group, and that therefore data on the Navy cannot be
applied directly to the Brazilian population as a whole.
PMID- 9761611
TI - [Trends in HIV/AIDS-related knowledge, attitudes, and practices in a Rio de
Janeiro slum population].
AB - The study aims to evaluate the present stage of knowledge, attitudes, and
behavior related to HIV/AIDS in the population of Rio de Janeiro's Rocinha slum,
the target of a control program over the last 6 years. We interviewed two hundred
and ten people of both sexes, ranging from 13 to 49 years of age, and the results
were compared with those of a study conducted in 1990 with the same methodology
and sample size. The analysis showed an association between single males and more
preventive behavior. Misconceptions about the role of mosquito bites and blood
donation in the transmission of HIV persist, almost in the same proportion.
Comparing the two samples, there was a significant increase in the role of
HIV/AIDS education provided by schools, and the study also identified an increase
in the rates and regularity of condom use. More efforts should be made to reduce
misconceptions about HIV transmission and the vulnerability of couples. The study
also highlights the need for more consistent policies related to condom
distribution to the general population.
PMID- 9761612
TI - [Health promotion and education: a diagnosis of sanitation conditions using
participatory research and community education (Sao Joao dos Queiroz -
Quixada/Ceara, Brazil)].
AB - This study was conducted in a rural community, Sao Joao dos Queiroz, a township
in the county of Quixada, Ceara, Brazil, using a combination of participatory
research and community education in compliance with the health promotion
reference and principles of the 1986 Ottawa Charter. The project was joined by
representatives of several local government institutions and organizations from
the grassroots community movement. The theme generating the research, as defined
by an assembly meeting of the community association, was a diagnosis of
sanitation conditions in the community. The starting point was the assessment of
local conditions. Results showed adverse local conditions in sanitation,
literacy, income, and employment. Suggestions for solving the problems were
organized so as to be included in the planning agenda for local health policies.
Evaluation was procedural and enriched with daily research activities. The
problem-solving pedagogical approach developed during the educational process
contributed to a critical reconstruction, appropriation, and sharing of the
resulting knowledge.
PMID- 9761613
TI - [Linkage of environmental and health data: health risk analysis of the Rio de
Janeiro water supply by using geographical information systems].
AB - Exposure assessment of population groups is based on linkage of environmental and
health data. This relationship can be hard to establish due to spatial and
temporal lags in data sets. Environmental data generally refer to scattered
sampling points, while epidemiological data integrate periods of time within
administrative territories. GIS can be used as a basis for organizing health
related and environmental data sets. We examined potential health risk in the Rio
de Janeiro city water supply based on the overlay of information layers
containing data on the presence and quality of water supply services. We used
census tracts as the primary georeferenced data, since they contain information
on how households are supplied, water supply pipes, sources, and reservoirs, and
water quality according to the monitoring program. Population groups exposed to
risks were located and quantified using spatial operations among these layers and
adopting different risk criteria. The main problems related to water supply are
located on the northern slope of the Tijuca Mountain Range (involving the absence
or poor quality of water) and in the western area of the city of Rio, where the
population relies on alternative water supply sources. The different origins,
objectives, and structures of data have to be analyzed critically, and GIS can be
used as a data validation tool as well as an instrument for detailed
identification of inconsistencies.
PMID- 9761614
TI - [Identifying areas of epidemiological stratification in an onchocerciasis focus
in Yanomami territory, Roraima, Brazil].
AB - In this paper, aimed at suitable planning, analysis, and follow-up of treatment,
control, and eradication in a human onchocerciasis program, were studied 27
geographic areas and examined 3,974 inhabitants. Four epidemiological areas with
different prevalences were identified and stratified.
PMID- 9761616
TI - [An anthropological investigation of old age and concepts concerning arterial
hypertension].
AB - Anthropology and sociology are joining epidemiology, clinical investigation, and
pathophysiology in studies on the aging process of the Brazilian population. The
objectives of the present study were: a) to identify the concepts of the elderly
population of the municipality of Araraquara, Sao Paulo, Brazil, towards the
etiology of arterial hypertension (AH) and the relevance of the different signs
and symptoms that accompany the disease; b) to improve elderly people's concepts
towards the relevance and utilization of different treatment categories for AH.
Structured interviews were conducted with 29 individuals, the majority aged 60
years or over, who were being treated for hypertension at the Araraquara
municipal gerontology outpatient clinic in August 1996. Patients were properly
informed by the health team about problems related to AH, as clearly perceived in
the discourse of the elderly. Folkloric concepts pertaining to etiology also
appeared in the interviews and should be taken into consideration in the
implementation of health education activities. Care provided by an
interdisciplinary team was valued by the elderly. The most frequent complaint was
the lack of free distribution of prescription medication for AH at the clinic.
PMID- 9761615
TI - [Surveillance of phytotherapeutic drugs in the state of Minas Gerais. Quality
assessment of commercial samples of chamomile].
AB - Marketing of medicinal plants and phytotherapeutic products is spreading all over
the world. In order to assess the commercialization of medicinal plants and
phytotherapeutic products in the State of Minas Gerais, we identified and tested
for the presence of adulterants and active ingredients in 27 samples of
chamomile. All the samples consisted of Matricaria recutita flowers, but they
were badly fragmented, a result of excessive handling and poor preservation. All
samples contained contaminants, and insects were observed in 63% of the samples
sold in drugstores. Only 50% of the samples in each group had the essential oils
needed to produce antiinflammatory activity. Flavonoids and other phenolic
constituents with a spasmolytic effect were detected in only 20% of the samples
from each group. Results with chamomile indicated the poor quality with which
medicinal plants and phytotherapeutic products are marketed and confirm the need
for surveillance of such products in Brazil.
PMID- 9761617
TI - [Quality control in primary health care. I - Consumer satisfaction].
AB - In this paper, the first of a series dealing with the development of a
methodology for assessing quality of ambulatory care, a sample of 270 outpatients
from the same health center were presented with a list of 12 questions. Although
different versions of the questionnaire were tested, we found a high degree of
agreement between the results. The findings indicate that the parameter
"satisfaction" lends itself readily to measurement, thus becoming a useful
instrument for guiding active intervention.
PMID- 9761618
TI - [An alternative for brazilian nutritional policy?].
AB - This article focuses on the alternative nutrition policy as a public policy
issue. It discusses such important and controversial questions as the efficacy
and safety of multimixture. It also analyzes six epidemiological studies focusing
on the evaluation of the reliability of results. The article concludes that the
numerous ambiguities, gaps, and contradictions in knowledge concerning
alternative nutrition do not support the incorporation of this intervention
proposal as a food and nutritional policy for Brazil.
PMID- 9761620
TI - [Hunger and mental illness].
AB - Based on a recently-published article on the triad of drought, hunger, and mental
illness, in which the main idea is that destitution may be leading to behavioral
disorders in the drought-plagued population of the Brazilian Northeast, we
reflect on what this so-called 'madness' may represent for this group of people.
We attempt to analyze the issue from various disciplinary perspectives, going
beyond merely causal explanations and taking into account that the reported
disorders entail meanings following the articulation of cognitive, affective, and
experiential elements founded on the social and cultural relations of
individuals. From this point of view, the respective discourse assumes other
interpretations, showing that illness is a singular process of construction.
PMID- 9761619
TI - [Foucault, Derrida, and the history of madness: notes on a controversy].
AB - The publication of the book Folie et Deraison. Histoire de la Folie a l'Age
Classique (1961), by Michel Foucault, sparked a debate between the author and
philosopher Jacques Derrida during the 1960s and 70s. Derrida criticized the
methodological proposal and organization of the History of Madness presented by
Foucault in the foreword to the first edition. The controversy appears to have
motivated the author to withdraw this same foreword from the second edition. The
purpose of this article is to analyze some current points in this controversy. It
also presents a research agenda for an understanding of the reasons leading
Foucault to take this stance.
PMID- 9761621
TI - Analysis of the Multilayer Thickness Relationship for Water Vapor and Nitrogen
Adsorption.
AB - Six silica gels, where each gel had a characteristic calibrated pore size (40
4000 A), have been characterized both by water vapor and nitrogen adsorption
isotherms. From these results, it was concluded that two-thirds of the silica
surface is hydrophobic. The selection of wide pores (>300 A) has enabled the
determination of both the water and nitrogen t-curves for porous silica. It was
observed that the development of the multilayer was identical in the wide pores
irrespective of their size between 300 and 4000 A. The porous silica t-curve for
water coincided exactly with the t-curve of nonporous adsorbents provided that
their BET C constants were similar. For nitrogen t-curves, a matching BET C
constant ensured similarity only in the monolayer region, above which divergence
progressively increased, becoming important close to saturation. The effect of
the t-curve choice on the pore size distribution was established. A t-curve
displaying reduced adsorption had a tendency to shift the pore-size distribution
to lower dimensions, toward the micropore region. As a consequence, the cumulated
surface area obtained from the BJH model gave increasingly higher values than the
BET nitrogen surface area. However, the pore-size distribution was shifted to
higher pore sizes when the selected t-curve was above the natural t-curve. Errors
as much as 25% were detected for the mean pore radius and cumulated surface area
for certain literature t-curves. A comparison of the water and the nitrogen t
curves indicated a crossover point when the water multilayer thickness became
greater than the nitrogen thickness. Such behavior lends support to the
cooperative adsorption mechanism for water vapor once a fixed number of water
molecules (two layers) are present on the surface. Copyright 1998 Academic Press.
PMID- 9761622
TI - Electrorotation of Deformable Fluid Droplets.
AB - An equilibrium phase separated ternary system of polystyrene
(PS)/polydimethylsiloxane (PDMS)/p-xylene was prepared, and the PS-rich phase was
dispersed as droplets in a matrix of the PDMS-rich phase. The system was placed
between vertical electrodes and the droplets rotated around a vertical axis
perpendicular to the electric field direction in 4-8-kV cm-1 DC fields; in 2-4-kV
cm-1, 0.1-Hz AC fields; and in 4-kV cm-1, 1-MHz AC fields, in some cases
stopping, restarting, and changing the direction of rotation. They rotated less
than a quarter of a turn back and forth in 1-10-Hz, 2-4-kV cm-1 fields and did
not rotate at all in 1-kHz fields. Rotational velocities measured in the DC field
were in agreement with an existing theory; those measured in the 0.1-Hz AC field
and estimated in the 1-MHz AC field were in direct disagreement with a different
existing theoretical treatment. When the PDMS-rich droplets were dispersed into a
matrix of the PS-rich phase, the droplets elongated in the field direction in a 2
kV/cm, 0.1-Hz electric field. Occasionally a portion of the matrix phase broke
off into the PDMS-rich droplet, rotated for a while, and then rejoined the matrix
phase. Copyright 1998 Academic Press.
PMID- 9761623
TI - Discrete Charge Distributions in Dielectric Droplets.
AB - The electrospray ion source has recently revolutionized mass spectrometry by
allowing researchers to produce gaseous ions of very large molecular weights such
as proteins and polymers. The process by which these high-molecular-weight ions
are produced, however, is not very well understood. The purpose of the present
work is to study the fields in the vicinity of each charge in order to shed some
light on the ion formation process for charged dielectric droplets. An important
feature of this work, therefore, is the treatment of the charge as discrete
rather than continuous. The picture that emerges is of discrete charges in a
dielectric droplet thermally oscillating around a potential well, located
slightly below the droplet surface. The charges produce localized electrostatic
pressures on the droplet surface that are higher (15.5 and 70% for dielectric
constants of 80 and 20, respectively) than expected if the charge distribution
were continuous. These high localized pressures could locally stretch the surface
and result in the emission of ions or small charged droplets. The magnitude of
these localized pressures is a function of the number of charges and the
dielectric constant of the droplet. Copyright 1998 Academic Press.
PMID- 9761624
TI - Anodic Surface Treatment on Carbon Fibers: Determination of Acid-Base Interaction
Parameter between Two Unidentical Solid Surfaces in a Composite System.
AB - An interpretation based on more precise linear free energy relationships is
proposed for the determination of the acid-base interaction of a solid surface,
in the context of inverse gas chromatography at infinite dilution. This work
leads to the evaluation of acid-base interaction parameter, Ia-b, between two
constitutive elements in a composite system. In this work, the acid-base
interaction parameters between fibers and matrix are greatly correlated with the
results of the interfacial shear strength carried out on single fibers and the
interlaminar shear strength of the composites. As an experimental result,
electrochemical treatment of fiber surfaces significantly appears essential to
the improvement of the acid-base character in a way expected from the nature of
the electrolytes used during the treatment. Copyright 1998 Academic Press.
PMID- 9761625
TI - Surface Behavior of Spread Sodium Eicosanyl Sulfate Monolayers.
AB - The surface behavior of spread sodium eicosanyl sulfate monolayers is
characterized by determining the dilational moduli from different pi/A isotherms
and from surface stress relaxation experiments in the short-time range (<10 min).
The elasticities derived from the pi/A isotherms differ depending on the
experimental conditions. The quasi-equilibrium isotherm displays a plateau in the
range of coexistence of the condensed and the expanded phases and strong
increases caused by the formation of a solid-like phase. In contrast,
nonequilibrium pi/A isotherms yield effective elasticities showing a maximum
within the phase coexistence range. The formation of a solid phase cannot be
detected because of the onset of monolayer collapse. Different stress relaxation
experiments were carried out for monolayer compression and dilation using
transient drop volume jumps. Depending on the experimental run, these experiments
lead to consistent and complementary results with those derived from pi/A
isotherms under comparable conditions. The stress recoveries yield a relaxation
time, a dilation viscosity, and a parameter characterizing the homogeneity of the
relaxation process. The stress relaxation is interpreted accounting for both the
nonequilibrium between the monolayer and the bulk phase and the nonequilibrium
within the monolayer. The influence of alkylsulfate hydrolysis on the presented
results was checked. It was found that within the time scale of the experiments
no influence of hydrolysis could be detected. Copyright 1998 Academic Press.
PMID- 9761626
TI - Low-Rate Dynamic Contact Angles on Poly(methyl methacrylate) and the
Determination of Solid Surface Tensions.
AB - Low-rate dynamic contact angles of nine liquids on a poly(methyl methacrylate)
(PMMA) polymer are measured by an automated axisymmetric drop shape analysis
profile (ADSA-P). It is found that two liquids dissolved the polymer on contact.
From the experimental contact angles of the other seven polar and nonpolar
liquids, it is found that the liquid-vapor surface tension times cosine of the
contact angle changes smoothly with the liquid-vapor surface tension (i.e.,
gammalnucos theta depends only on gammalnu for a given solid surface). The
dependence of gammalnucos theta on gammasnu is explicitly illustrated by
replacing the solid surface from the PMMA to other methacrylate polymers: such a
procedure shifts the curves in a very regular manner. Thus, because of Young's
equation, gammasl depends only on gammalnu and gammasnu. This contact angle
pattern is in harmony with those from other inert and noninert (polar and
nonpolar) surfaces. The solid-vapor surface tension of PMMA calculated from the
equation of state approach for solid-liquid interfacial tensions is found to be
38.5 mJ/m2, with a 95% confidence limit of +/-0.5 mJ/m2 from the experimental
contact angles of the seven liquids. Copyright 1998 Academic Press.
PMID- 9761627
TI - New Carbon-Silica Composite Adsorbents from Elutrilithe.
AB - Carbon-silica composite adsorbents with high surface area and pore volume were
prepared from natural elutrilithe. The elutrilithe was chemically activated with
K2CO3 at 1123 K and then dissolved in water. The textural and adsorptive
properties of the composite adsorbents can be adjusted by varying the pH and
concentration of the sol mixture and the gel aging temperature. Composite
adsorbents prepared at low concentration have high adsorption capacities for both
water (43.4%) and cyclohexane (32.0%), exceeding those of ordinary commercial
silica gel and active carbon. The adsorbents prepared at high concentration are
more hydrophobic in nature, with adsorption capacities for water and cyclohexane
of 18.5 and 41.5%, respectively. The composite adsorbents are resistant to
repetitive adsorption and regeneration cycles. Copyright 1998 Academic Press.
PMID- 9761628
TI - Changes in Hydration Properties of Silica Gel in a Process of Its Carbonization
by Pyrolysis of Acetylacetone Zn (Ti) Acetylacetonates.
AB - Changes in hydration properties of different compounds in a process of formation
of a complex adsorbent comprising carbon and TiO2 or Zn2SiO4 on its surface were
studied by 1H NMR spectroscopy under conditions of a liquid phase freezing.
Adsorbents were synthesized on the basis of a mesoporous silica gel, the surface
of which was covered with a carbon layer formed in a process of a high
temperature pyrolysis of acetylacetone. Titanium oxide and zinc silicate on the
surface of a parent silica gel were formed by a pyrolysis of acetylacetonates of
the corresponding metals. It has been revealed that the main types of surface
active sites for the adsorbed water molecules on the carbosil surface are the
systems of condensed benzene nuclei of a carbon component of the surface and
hydroxyl groups of silica surface. Zn2SiO4 and TiO2 have been formed in a process
of pyrolysis of the corresponding metal acetylacetonates. Water bound with the
oxide component of the carbosil surface exceeds 80% of the total amount of the
adsorbed water. The carbon component of the surface is localized mainly in the
narrowest pores. A minimum value in the free surface energy was recorded for the
carbosil sample. Copyright 1998 Academic Press.
PMID- 9761629
TI - A Study of the Aggregation Behavior of Hexyltrimethylammonium Bromide in Aqueous
Solution.
AB - The self-association of n-hexyltrimethylammonium bromide (C6TAB) in aqueous
solution has been examined as a function of temperature and electrolyte
concentration. The critical micelle concentration (CMC) and the degree of
counterion binding (beta) were determined by conductivity measurement at
temperatures over the range 288.15-318.15 K. Ultrasound velocity measurements
were used to obtain the CMC in water and in a range of concentrations of
electrolyte (0.1 to 0.6 mol kg-1 NaBr) and static light scattering to obtain the
aggregation number and the degree of counterion binding in water at 298.15 K. The
enthalpy change on micellization in water was measured by microcalorimetry.
Apparent adiabatic compressibilities were calculated from a combination of
density and ultrasound velocity measurements. Changes in the thermodynamic
properties on micellization were determined by applying the mass action model;
good agreement was found between experimental and theoretical enthalpy changes.
From comparison with the properties of other n-alkyltrimethylammonium bromides it
has been shown that the CMC of C6TAB in water is lower than that predicted from
the linear relationships between CMC and the number of carbon atoms in the alkyl
chain. Similarly, the standard Gibbs energy of micellization is less negative
than predicted, and the degree of counterion binding is much lower than for other
CnTABs. It is suggested that the anomalous behavior of C6TAB is a consequence of
the more highly organized core of the aggregates of very low aggregation number
(3-4) and the high degree of exposure of the micellar components to the aqueous
environment. Copyright 1998 Academic Press.
PMID- 9761630
TI - Effect of Polyoxybutylene Chain Length on the Surface Activity of Butylene Oxide
Ethylene Oxide Block Copolymers.
AB - Block copolymer surfactants (RBE) obtained by the addition of ethylene oxide to n
butyl, n-hexyl, n-octyl, and n-decyl ethers of mono- to tetrabutylene glycol are
described. The surface activity of these nonionic surfactants has been
determined, i.e., critical micelle concentration (CMC), surface excess
concentration, Gamma, surface area demand per molecule, A, surface tension at
CMC, gammaCMC, and DeltaG degreesads. A linear decrease of log CMC vs number of
oxybutylene units in a copolymer molecule is observed. The change in the work of
cohesion per oxybutylene group when passing from a molecular into a micellar
state, calculated from the Shinoda equation, is 0.99-0.92 kT for the studied
compounds. The equivalent of CH2 in the aliphatic alcohol group is 1.06-1.15
oxybutylene units. Surface properties of these surfactants, i.e., cloud point,
wetting ability, contact angle, and foam height, have also been determined.
Copyright 1998 Academic Press.
PMID- 9761631
TI - Effect of Surface Mobility on Collision of Spherical Drops.
AB - The collision of two spherical liquid drops is considered which allows the effect
of coalescence on the formation and stability of dispersions to be studied. An
analytical solution is derived for the variation in the hydrodynamic force with
the approach velocity and the separation thickness during the impact in terms of
the drop diameter, allowing for the effect of induced flow inside the drops.
Setting this force equal to the rate of change of momentum of the drops enables
the variation with time in the separation between the drops to be obtained in
terms of the initial approach velocity, drop diameter, and viscosity ratio. The
analysis also yields the time variation in the force and approach velocity. For a
given impact velocity, the separation thickness decreases with time until a
minimum value is reached, which decreases as the impact velocity and the
viscosity ratio of the continuous and dispersed phases increase. Previous authors
have only obtained the variation in the approach velocity with the unknown
variable force and separation thickness during the impact and therefore could not
obtain the variation in the separation thickness with time. Knowing this
variation enables the possibility of coalescence during impact to be
investigated. Coalescence is influenced by the minimum separation thickness
attained at low impact velocities and by drop deformation and inertial drainage
at high velocities. Copyright 1998 Academic Press.
PMID- 9761632
TI - Removal of Fluoride from Aqueous Solution by Using Alum Sludge.
AB - The ability of treated alum sludge to remove fluoride from aqueous solution has
been investigated. The studies were carried out as functions of contact time,
concentration of adsorbent and adsorbate, temperature, pH, and effect of
concentrations of other anions. The data indicate that treated alum sludge
surface sites are heterogeneous in nature and that fits into a heterogeneous site
binding model. The optimum pH for complete removal of fluoride from aqueous
solution was found to be 6. The rate of adsorption was rapid during the initial 5
minutes, and equilibrium was attained within 240 minutes. The adsorption followed
first-order rate kinetics. The present system followed the Langmuir adsorption
isotherm model. The loading factor (i.e., the milligram of fluoride adsorbed per
gram of alum sludge) increased with initial fluoride concentration, whereas a
negative trend was observed with increasing temperature. The influence of
addition of anions on fluoride removal depends on the relative affinity of the
anions for the surface and the relative concentrations of the anions. Copyright
1998 Academic Press.
PMID- 9761633
TI - Removal of Organic Films From Rotating Disks Using Aqueous Solutions of Nonionic
Surfactants: Effect of Surfactant Molecular Structure.
AB - In prior work, we examined the removal of abietic acid films from rotating
fiberglass laminate disks by aqueous solutions of a nonionic surfactant. A three
stage cleaning mechanism was found, consisting successively of solubilization,
shear-driven cleaning, and roll-up. We extend this work by exploring the
influence of the surfactant molecular structure on the kinetics of the cleaning
process. Five different poly(ethylene glycol) alkyl ether surfactants (CxEy) were
used. Both the alkyl (x) and ethoxy (y) chain lengths were varied. Not all of the
surfactants exhibited a three-stage cleaning mechanism. It was found that for
surfactants with relatively high solubilization rates, the shear-driven cleaning
stage did not occur. The selection of the most efficient surfactant depends on
whether the surfactant concentration is below or above its critical micelle
concentration (CMC). At submicellar concentrations, faster cleaning is obtained
by surfactants that can induce shear-driven removal. At concentrations above the
CMC, it is found that surfactant efficiency for a fixed alkyl or ethoxy chain
length increases as the surfactant becomes more hydrophilic. This is attributed
in part to the lower viscosity that the film achieves with the more hydrophilic
surfactants due to their partitioning into the film, as well as their ability to
carry water into the film. Copyright 1998 Academic Press.
PMID- 9761634
TI - Influence of Surfactant Structure on the Drainage of Nonionic Surfactant Foam
Films.
AB - The stability of vertical liquid films produced from aqueous solutions of
polyoxyethylene alkyl ether (CnEm) was studied by monitoring the dynamic surface
tension (gammat) and aqueous core thickness of a vertical foam film (d2) measured
by FT-IR. The temperature dependence of the drainage patterns of the liquid films
was clarified for CnE8 (n = 10, 12, 14, and 16) solutions. It was found that the
critical thickness (Drup) where the film rupture happens increased with
increasing temperature in the case of C10E8 and C12E8, while Drup remarkably
decreased and finally formed a black film in the case of C14E8 and C16E8
solutions within the measured temperature range. In addition, a delay in the film
drainage occurred in these systems, which was caused by the stabilization of the
films via the Marangoni effect proved by dynamic surface tension measurements. On
the other hand, heterogeneous ethoxylated dodecyl ethers (C12Em) modified with a
hydrophilic group showed a remarkable increment of Drup under dynamic conditions
without the Marangoni stabilization in the foam film. Adding a hydrophobic group
at the end of the polar head produces a large area per molecule and causes a
large increase in the surface coverage of the air bubbles. However, a less
structured surface coverage facilitated the breaking of the foam during the Ross
and Miles test. These results indicate that under dynamic conditions, the
Marangoni effect and the hydrophobic interaction at the surface become important
for foam film rupture. Copyright 1998 Academic Press.
PMID- 9761635
TI - Acid-Base Properties and Heavy and Alkaline Earth Metal Adsorption on the Oxide
Solution Interface: Non-Electrostatic Model.
AB - A new approach was applied to the description of acid-base properties and heavy
and alkaline earth metal adsorption on the oxide-solution interface. The acid
base properties of hematite have been determined at different temperatures. The
adsorption of protons and hydroxyl ions on the hematite surface has a temperature
independent character. The proton and hydroxyl ion adsorption in NaCl media was
explained by the reactions. &tbond;H2O + H3O+ + Cl- = &tbond;H2OHCl + H2O
&tbond;OH2 + OH- + Na+ = &tbond;OHNa + H2O. The modified equation of the Frumkin
Fouler-Guggenheim isotherm was used to simulate the experimental data (theta,
relative adsorption): log[thetaHCl/(1 - thetaHCl)] - log[H+] - log[Cl-] = log
KoHCl + log BH[NthetaHCl/(1 + (N - 1)thetaHCl)]; log[thetaNaOH/(1 - thetaNaOH)] -
log[Na+] - log[OH-] = logKoNaOH + logBOH[NthetaNaOH/(1 + (N - 1)thetaNaOH)]. The
model parameters were log BH = -4.92 +/- 0.1, log BOH = -2.61 +/- 0.05, N = 3.25
+/- 0.2. The site density of the hematite surface was determined to be 3.8 +/-
0.1 u moles/m2. The values of the constants were log KoHCl (25-100 degreesC) =
9.50 +/- 0.1; log KoNaOH (25-100 degreesC) = 5.93 +/- 0.1. Copyright 1998
Academic Press.
PMID- 9761636
TI - Study of Copper Complexes Absorbed on a Silica Gel Surface Chemically Modified
with 5-Amino-1,3,4-thiadiazole-2-thiol.
AB - The isotherms of adsorption of CuX2 (X = Cl-, Br-, ClO-4) by silica gel
chemically modified with 5-amino-1,3,4-thiadiazole-2-thiol were studied in
acetone and ethanol solutions, at 25 degreesC. The following equilibria constants
(in L mol-1) were determined: (a) CuCl2, 3.2 x 10(3) (ac), 2.5 x 10(3) (eth); (b)
CuBr2, 2.9 x 10(3) (ac), 2.3 x 10(3) (eth); (c) Cu(ClO4)2, 1.8 x 10(3) (ac), 1.2
x 10(3) (eth); ac, acetone; eth, ethanol. The electron spin resonance spectra of
the surface complexes indicated a tetragonal-distorted structure in the case of
lower degrees of metal loading on the chemically modified surface. The d-d
electronic transition spectra showed that for the ClO-4 complex, the peak of
absorption did not change for any degree of metal loading and for Cl- and Br-
complexes, the peak maxima shifted to higher energy with lower metal loadings.
Copyright 1998 Academic Press.
PMID- 9761637
TI - Electrostatic Interactions in Adsorbed Protein Layers Probed by a Sedimentation
Technique.
AB - A simple centrifugation technique has been used to determine the thicknesses of
layers of alphaS1-casein and beta-casein adsorbed onto monodisperse polystyrene
latex particles. The influence of electrostatic interactions within the layers on
their thickness and stabilizing ability is investigated by varying the ionic
strength of the suspension or by including calcium ions, known to bind
specifically to the caseins. Copyright 1998 Academic Press.
PMID- 9761638
TI - The Effects of Flocculation on the Propagation of Ultrasound in Dilute Kaolin
Slurries.
AB - A broadband ultrasonic spectrometer has been used to measure ultrasonic
attenuation and phase velocity dispersion as functions of frequency in kaolin
suspensions over a range of solid volume fractions from phi = 0.01 to phi = 0.08
and over a pH range from 3 to 9. The Harker and Temple theory was used to
simulate ultrasound propagation in the suspension, using measured slope
viscosity, particle size, and size distribution. Simulated results for ultrasonic
attenuation and phase velocity agree well with measured values. Both sets of
results agree well and show that for volume fractions above phi approximately
0.05 attenuation and velocity dispersion increase for increasing floc size,
whereas for volume fractions below phi approximately 0.05 attenuation and
velocity dispersion both decrease. It is proposed that the mechanism for this
change in behavior around phi approximately 0.05 involves changes in floc density
and floc size distribution with phi and pH. Copyright 1998 Academic Press.
PMID- 9761639
TI - Aggregation Behavior of Sugar Surfactants in Aqueous Solutions: Effects of
Temperature and the Addition of Nonionic Polymers.
AB - The aggregation behavior, critical micelle concentration (cmc) and micelle
aggregation number (N), of dodecyl maltoside (DM), octyl glucoside (OG), and
Hecameg has been investigated in water and in water plus one of the three water
soluble polymers, polyoxyethylene (POE), polyoxypropylene (POP), and polyvinyl
pyrrolidone (PVP), by means of florescence probing and time-resolved fluorescence
quenching. The cmc of DM in water increased with temperature and showed a slight
increase in the presence of POE. The aggregation number N of DM micelles was
nearly independent of concentration (0.25-1 wt %) and temperature (16-60
degreesC). It remained invariant upon addition of 2 wt % POE or PVP but decreased
slightly upon addition of the more hydrophobic POP. With increasing temperature,
the cmc of OG decreased, went through a shallow minimum at around 35 degreesC,
and increased. Addition of POE slightly increased the cmc in the whole
temperature range. The aggregation number of OG micelles showed a fairly flat
maximum at around 30 degreesC, and was unaffected by the presence of 2 wt % POE
or PVP. However, N showed a complex dependence on temperature in the presence of
POP, with lower values than in pure water below 15 degreesC, and rapidly
increasing quencher-dependent values above this temperature. Hecameg was
characterized by N-values nearly independent of temperature and concentration.
Intermicellar exchanges of probe and/or quencher were observed with OG and
Hecameg, but not with DM. The above results are compared to those for the
nonionic ethoxylated surfactants. The effect of various parameters on the micelle
aggregation number, the micelle polydispersity, the occurrence of sugar
surfactant/nonionic polymer interactions, and the mechanisms responsible for the
observed intermicellar exchanges are discussed. Copyright 1998 Academic Press.
PMID- 9761640
TI - 1H NMR Self-Diffusion in Polymer-Surfactant Nanocapsules and Cryogels with
Enzyme.
AB - The multicomponent self-diffusion in nanocapsules and cryogel biocatalytic
systems containing alpha-chymotrypsin has been studied with the NMR-PGSE method
at various temperatures and compared with the diffusion of such systems without
enzyme. Unilamellar vesicles have been formed in water after "coating" with Brij
97 of the poly-(N,N-diallyl-N,N-didodecyl ammonium bromide), poly-DDAB,
nanocapsules. The latter have been obtained by UV-irradiation of reversed
hydrated micelles from DDAB in cyclohexane. Cryogels were made from poly(vinyl
alcohol), PVA, aqueous solutions by a freezing-thawing cyclic process. Both
compartmented systems were used as vehicles of the enzyme entrapped in inner
aqueous cavities. The activation energies of self-diffusion for both these
systems have been calculated. These data contain information concerning
morphology and molecular packing. Encapsulation of alpha-chymotrypsin in the poly
DDAB/Brij-97 vesicles and the PVA cryogel lowers the Ds values for all molecules
and shifts the cloud point toward the lower temperature. On the contrary, the
syneresis point for the PVA cryogel is shifted for 8 degrees toward the higher
temperature by the entrapment of the enzyme. Besides, entrapment of alpha
chymotrypsin in the cryogel promotes the increase of the Ea values for the PVA
chain on 1.5 kJ/mol below the syneresis point. Such a difference indicates the
influence of the H-bond system of PVA hydroxyl groups and water molecules on the
interference of the protein globule. Entrapment of alpha-chymotrypsin leads to
consolidation of this H-bond system. Copyright 1998 Academic Press.
PMID- 9761641
TI - Compositional Homogeneity of Liposomal Membranes Investigated by Capillary
Electrophoresis.
AB - Capillary electrophoresis has been demonstrated to be a new powerful tool for
investigating the compositional homogeneity of liposomal membranes composed of
phospholipids and guest molecules. In the case of charged components distributed
heterogeneously on membranes, electropherograms show several distinguishable
peaks even with monodisperse size distributions of liposomes because each
liposomal particle carries a different amount of charge. The heterogeneity of
noncharged components, when the lipids and the guest components have
significantly different molar absorptivities at two different wavelengths, can
also be judged from the signal ratio observed at the two wavelengths using a
photodiode array detector. This new method can be used for the quality control of
liposomal products. Copyright 1998 Academic Press.
PMID- 9761642
TI - The Role of Ionic Surfactants in Compression Dewatering of Alum Sludge.
AB - This work has experimentally investigated the characteristics of filtration
followed by consolidation dewatering of an alum sludge, with especial attention
to the effects of adding ionic surfactants (SDS or CTAB). The filtration and
consolidation stages at a pressure of 3000 psi were discussed separately. The
efficiency of filtration is enhanced in the presence of surfactant molecules;
however, the cationic surfactant (CTAB) raises the consolidation rate while the
anionic surfactant (SDS) retards it. A newly proposed rheological model has been
employed for interpreting the consolidation data. CTAB would not alter markedly
the moisture distribution in the sludge, but SDS does increase markedly the
amount of the tightly bound moisture by diminishing the portion occupied by pore
water. The possible role of surfactants in the sludge flocs is considered. Both
surfactants can be used as conditioning aids during the filtration stage.
However, the applications of SDS to the consolidation stage are not encouraged.
Copyright 1998 Academic Press.
PMID- 9761643
TI - Effect of Interfacial Tension on the Formation of the Gradient Morphology in
Polymer Blends.
AB - In order to investigate the effect of interfacial tension on the formation of
gradient phase morphology in polymer blends, a saponification reaction was
carried out in this study to obtain several kinds of EVA with different contents
of -OH groups. These EVAs with different -OH contents, namely with different
polarities, were then blended with PP, and thus a series of PP/EVA blends with
different interfacial tensions was obtained. The same initial droplet size could
be obtained for PP/EVA blends with different interfacial tensions during
compounding through adjusting the degree of saponification of EVA. It was found
that all these PP/EVA blends could form a gradient morphology in the vertical
section of the samples as PP/EVAc blends. Using a computer image analyzer, the
vertical distributions of the dispersed droplet size and the EVAc component in
each blend were determined. The results showed that the EVA droplet size and the
EVA component increased in the vicinity of the sample surface with increasing
interfacial tension of the blends; i.e., the greater the interfacial tension
between PP and EVA, the larger the gradient tendency in the blend. Copyright 1998
Academic Press.
PMID- 9761644
TI - Effect of Nonionic Surfactant on the Deformation and Breakup of a Drop in an
Electric Field.
AB - We have examined deformation and breakup of fluid drops suspended in another
immiscible fluid under the action of an electric field. The contiguous fluids are
incompressible Newtonian and the fluid-fluid interface is populated by nonionic
surfactant molecules. The presence of the nonionic surfactant affects both the
degree of deformation and the modes of breakup through the so-called Marangoni
flow resulting from its nonuniform distribution on the interface. The drop is
deformed into either a prolate or an oblate spheroid depending upon the
electrical properties of the fluids and sustains a steady-state shape until the
electrical Weber number is above a certain critical value. Two distinctively
different modes of the drop breakup are observed depending on the surfactant
concentration. When the interface is clean or contaminated by a very small amount
of surfactant molecules, the drop bursts into several small droplets after
forming bulbous ends. There exists a certain range of the surfactant
concentration in which tip-steaming is a prevalent drop breakup mode. If the
surfactant concentration exceeds this range, the breakup mode goes back to the
fragmentation with bulbous end formation. This shows that, although not
pronounced in the small deformation limit, nonuniformity in the surfactant
distribution is a decisive factor for the breakup mechanism of a prolate
spheroid. The results also show that when the drop deforms into an oblate
spheroid, the effect of nonuniform distribution of surfactant can be significant.
Copyright 1998 Academic Press.
PMID- 9761645
TI - Surface Structure and Properties of Calcium Hydroxyapatite Modified by
Hexamethyldisilazane.
AB - The surface of synthetic calcium hydroxyapatite Ca10(PO4)6(OH)2 (CaHAP) particles
was treated by repeated modification with hexamethyldisilazane [(CH3)3Si]2NH
(HMDS) in hexane and thermal treatment and the surface of the modified CaHAP was
characterized by various means. No remarkable change in XRD patterns or in
particle shape by the modification was observed. The width of the CaHAP particles
gradually increased with repeating the modification. FTIR results indicated that
HMDS reacted with surface P-OH groups of CaHAP to yield surface Si-(CH3)3 groups.
The surface of the modified CaHAP was hydrophobic. The surface Si-(CH3)3 groups
turned to three kinds of surface Si-OH groups by treating the modified materials
at 500 degreesC in air. These formed surface Si-OH groups and the remaining
surface P-OH groups reacted with HMDS by repeating the modification, resulted in
the increase of the surface Si atoms. The modified material having surface Si
(CH3)3 or Si-OH groups adsorbed much less CO2 than the unmodified one. Copyright
1998 Academic Press.
PMID- 9761646
TI - The Denaturation of Lysozyme Layers Adsorbed at the Hydrophobic Solid/Liquid
Surface Studied by Neutron Reflection.
AB - We have studied the adsorption of lysozyme layers at a hydrophobic silicon water
interface using specular neutron reflection. The hydrophobic surface was obtained
by self-assembly of a densely packed monolayer of octadecyltrichlorosilane (OTS)
onto the natural silica layer on the smooth surface of a (111) silicon block. The
effect of pH on the adsorbed lysozyme layer was examined at a constant lysozyme
concentration of 0.03 g dm-3 and at a constant ionic strength of 0.02 M.
Reflectivity profiles at different pH show that adsorption is irreversible with
respect to pH, the composition and structure of the final layer being dependent
on the route by which the pH was achieved. The adsorbed protein layer was found
to divide into approximately two regions, a densely packed thin layer next to the
OTS surface and a diffuse thicker layer extending into the bulk solution. None of
the dimensions of this structure corresponds to those of the globular protein in
solution, suggesting that, unlike its adsorption at the hydrophilic silica/water
interface, lysozyme is denatured at the OTS/water surface. The irreversible
adsorption is explained by the combined interaction of the hydrophobic attraction
of the hydrophobic fragments in lysozyme to the OTS surface and electrostatic
repulsion within the adsorbed layer. The hydrophobic surface induces the exposure
of hydrophobic fragments from the lysozyme assembly. The thickness of the dense
layer suggests that the denatured protein adsorbs in the form of peptide chains
with the hydrophobic amino acid side chains attached to the OTS surface with the
hydrophilic side chains extending into the bulk solution. Since lysozyme is more
stable at pH 7 than at pH 4, the difference in initial adsorption is dominated by
the greater relative stability of lysozyme to denaturation at the higher pH. A
change of pH from 7 to 4 reduces the stability of the protein to unfolding and
results in more adsorption than when the pH is changed in the opposite direction.
Solution pH also affects the net charges within the hydrophilic tail region and
the structural distribution of the tail region was found to vary with pH.
Copyright 1998 Academic Press.
PMID- 9761647
TI - Effect of Co-Adsorbed Surfactant on the Structure of Self-Assembled Monolayer of
Thiol on Polycrystalline Gold.
AB - The structure and formation kinetics of a self-assembled monolayer (SAM) of long
chain alkane thiol in the presence and absence of an anionic surfactant like
sodium dodecyl sulfate (SDS) has been studied using impedance, cyclic
voltammetic, and quartz crystal microbalance (QCM) measurements. The comparison
of these results, especially the ionic permeability of the monolayer, suggests a
composite monolayer where both the surfactant and thiol molecules are
cooperatively adsorbed to form distinct surfactant patches. This is further
substantiated by the voltammetric experiments with redox probe in solution. A
gradual change in the double layer capacitance value for the thiol monolayer
alone (1.4 uF/cm2) to the composite monolayer (6.7 uF/cm2) and to the surfactant
alone (11 uF/cm2) further supports the nature of the mixed monolayer. The
kinetics of monolayer formation also shows interesting changes as revealed by the
QCM studies, where a phase transition from simple to composite monolayer has been
observed around an approximate coverage of 0.44. The same growth scheme is also
observed for 1-pentanethiol, naphthalene disulfide, and diphenyl disulfide,
suggesting that the mechanism appears to be general. Copyright 1998 Academic
Press.
PMID- 9761648
TI - Direct Determination of the Dependence of the Surface Shear and Dilatational
Viscosities on the Thermodynamic State of the Interface: Theoretical Foundations.
AB - Recent developments in nonlinear optical techniques for noninvasive probing of a
surfactant influenced gas/liquid interface allow for the measurement of the
surfactant surface concentration, c, and thus provide new opportunities for the
direct determination of its intrinsic viscosities. Here, we present the
theoretical foundations, based on the Boussinesq-Scriven surface model without
the usual simplification of constant viscosities, for an experimental technique
to directly measure the surface shear (us) and dilatational (kappas) viscosities
of a Newtonian interface as functions of the surfactant surface concentration.
This ability to directly measure the surfactant concentration permits the use of
a simple surface flow for the measurement of the surface viscosities. The
requirements are that the interface must be nearly flat, and the flow steady,
axisymmetric, and swirling; these flow conditions can be achieved in the deep
channel viscometer driven at relatively fast rates. The tangential stress balance
on such an interface leads to two equations; the balance in the azimuthal
direction involves only us and its gradients, and the balance in the radial
direction involves both us and kappas and their gradients. By further exploiting
recent developments in laser-based flow measuring techniques, the surface
velocities and their gradients which appear in the two equations can be measured
directly. The surface tension gradient, which appears in the radial balance
equation, is incorporated from the equation of state for the surfactant system
and direct measurements of the surfactant surface concentration distribution. The
stress balance equations are then ordinary differential equations in the surface
viscosities as functions of radial position, which can be readily integrated.
Since c is measured as a function of radial position, we then have a direct
measurement of us and kappas as functions of c. Numerical computations of the
Navier-Stokes equations are performed to determine the appropriate conditions to
achieve the requisite secondary flow. Copyright 1998 Academic Press.
PMID- 9761649
TI - The Interfacial Polarization-Induced Electrorheological Effect.
AB - The Wagner theory, which describes the interfacial polarization in heterogeneous
systems, was employed to model the electrorheological (ER) effect under the
presumption that the shear stress increment is induced by the interfacial
polarization. The currently observed experimental facts, such as the yield stress
of some ER fluids, decreases with the applied field frequency increasing or the
environment temperature decreasing, while that of other fluids increases with the
frequency decreasing or temperature increasing; the strongest ER effect is
usually observed in the suspension with the dispersed particle conductivity
around 10(-7) S/m; the particle dielectric loss tangent of a good ER fluid
usually is above 0.10 at 1000 Hz; and the fluid with a high conductive particle
usually has a short response time, can be satisfactorily understood with the
extended Wagner model. The Wagner-polarization-induced maximum yield stress of a
heterogeneous-type ER fluid is estimated around 7 kPa under the presumption that
the dielectric constants of the solid particle and the liquid medium are 10 and
2, respectively, the particle volume fraction is 35%, and the applied electric
field strength is 3 kV/mm. It is concluded that the ER effect may substantially
correlate with the Wagner polarization, which would help in understanding the
mechanism of the ER effect and would provide a strategy for designing high
performance ER fluids. Copyright 1998 Academic Press.
PMID- 9761650
TI - The Interfacial Chemistry of the Grignard Reaction: The Composition of the Film
Formed on Air-Exposed Magnesium.
AB - X-ray photoelectron spectroscopy has been used to monitor the composition of the
surface film formed when a clean Mg metal is subjected to pretreatments that
simulate exposure to ambient environments. The results indicate that an as
received (commercial) Mg metal contains a surface covered by a film constituted
predominantly by magnesium hydroxide and a smaller but appreciable quantity of
magnesium bicarbonate. These observations have important ramifications in the
mechanistic description of the Grignard reaction since the interaction between Mg
metal and an alkyl halide must contend with the surface hydroxide and bicarbonate
films. Copyright 1998 Academic Press.
PMID- 9761651
TI - Comparison of the Adsorption of o-Phthalate on Boehmite (gamma-AlOOH), Aged gamma
Al2O3, and Goethite (alpha-FeOOH).
AB - This work is concerned with the adsorption of o-phthalate (1,2
benzenedicarboxylate) at the water-metal (hydr)oxide interface. Previously
published infrared spectroscopic, potentiometric, and adsorption data
characterizing the boehmite (gamma-AlOOH) system are compared with new data
collected for o-phthalate adsorption on aged gamma-Al2O3 and goethite (alpha
FeOOH). The study focuses on identifying bonding mechanisms, stoichiometries, and
stabilities of the formed complexes, and comparing these among the three systems.
Furthermore, the effects of ionic strength and composition of the ionic medium
are investigated. The infrared spectroscopic data provided direct, molecular
level evidence for the existence of two dominating surface complexes on all three
solids. One was shown to be a deprotonated outer-sphere species and the other was
an inner-sphere surface complex. The inner-sphere complexes on the three solids
were structurally related, and they were tentatively assigned to a mononuclear,
chelating structure involving both carboxylate groups. The outer-sphere complexes
were shown to increase in relative importance at high pH and low ionic strengths,
while low pH and high ionic strengths favored the inner-sphere complexes. The
information gained from the infrared spectroscopic investigations was used as
qualitative input in the formulation of the surface complexation models. New
models, based on the extended constant capacitance approach, were presented for
the o-phthalate/aged gamma-Al2O3 and o-phthalate/goethite systems. Copyright 1998
Academic Press.
PMID- 9761652
TI - Aggregation of Silver Hydrosols Prepared in Air.
AB - The chemistry involved in the preparation and activation of silver hydrosols was
monitored by pH, potential, and surface charge measurements, by absorption
spectra in the visible region, and by surface-enhanced Raman spectroscopy (SERS).
The activation, displayed by a red-shift of the colloid absorption at 392 nm,
corresponds to a partial aggregation of elementary silver particles as displayed
by transmission electron micrographs. The participation of carbonate species in
the chemistry of hydrosols handled in air was made obvious by titration with
strong acids. The colloid destabilization was performed either with protons, by
adding strong non-complexing acids (HNO3, HClO4), or with low concentrations of
Cu2+. In contrast, HCl determined a stabilization of hydrosols related to the
complexing affinity of Cl- toward silver. The successive addition of Cu(NO3)2 and
HCl allowed a balance between all the chemical reactions and a very efficient
activation process. Whereas the chemical reactants used are nominally inorganic,
at total concentrations lower than 10(-3) M, the activated hydrosols display
anomalous SER spectra which were previously assigned to organic molecules.
Copyright 1998 Academic Press.
PMID- 9761653
TI - Dispersion Properties of Silicon Nitride Powder Coated with Yttrium and Aluminium
Precursors.
AB - A coated silicon nitride (Si3N4) powder with yttria and alumina precursors as
sintering additives was prepared by a heterogeneous precipitation method. The
rheological and electrophoretic properties of the suspensions obtained from the
coated (CO) powder were investigated and compared with those of pure Si3N4 powder
and of the mechanically mixed (MM) powders of Al2O3, Si3N4, and Y2O3. The results
showed that the CO powder calcined at 500 degreesC exhibited improved dispersion
properties compared with the pure Si3N4 powders. The CO powder possessed the
surface character of Al2O3 and Y2O3 particles, that made it easier to process in
aqueous media, yielding a higher solid loading than the pure Si3N4 powder. These
improvements were attributed to a change in the resultant interaction forces
between particles from attractive (pure Si3N4, and MM powders) to repulsive in
the case of the CO powder. A homogeneous distribution of sintering additives in
the Si3N4 matrix was obtained. Copyright 1998 Academic Press.
PMID- 9761654
TI - Covalent Grafting of Phenylphosphonate Groups onto the Interlamellar Aluminol
Surface of Kaolinite.
AB - Kaolinite (K) was reacted with phenylphosphonic acid (PPA) in a water:acetone
(1:1 V/V) solution (molar ratio 1 K:3 PPA), at 95 +/- 5 degreesC for different
periods of time. Two different compounds (white powders) were identified but only
one was isolated as a single phase and characterized by X-ray diffraction (powder
method), thermal analysis (TG-DSC), Fourier-transformed infrared spectroscopy,
and chemical analysis. The first compound showed a layer expansion of 7.86 A and
the second, a layer expansion of 9.29 A, obtained as a decomposition product.
Both compounds are consistent with the grafting of the phenylphosphonate group to
the layers of kaolinite. The compounds have a formula of Al2Si2O5(OH)(HO3PPh)3.0
. 2H2O, as determined by thermal (water and total organic matter loss) and
chemical (C content) analysis, respectively. Copyright 1998 Academic Press.
PMID- 9761655
TI - Measurements of Contact Angles between an Oil-Water Interface and a Fiber by the
ACDPAC Technique.
AB - The ACRPAC (Analysis of Capillary Rise Profile Around a Cylinder) method was
modified and extended to measure the contact angles between an oil-water
interface and a fiber. Basically, the accurate image of the partial capillary
depression profile was acquired and digitized by applying computer digital image
processing and analysis techniques. The contact angle was determined by finding
the best fit of the theoretically predicted profile, i.e., the curve representing
a solution of the Laplace equation of capillarity, to the physically observed
liquid-liquid interface. This analysis of the capillary depression profile around
a cylinder (ACDPAC) technique was used to measure the contact angles of different
water-oil interfaces on cylindrical glass fibers pre-coated with FC725. The
wettability of the fiber-water-oil systems with varying oil and aqueous phases
was examined. In particular, the wetting effects of a cationic surfactant
cetyltrimethylammonium bromide (CTAB) and an anionic surfactant sodium dodecyl
sulfate (SDS) dissolved in the aqueous phase were studied by using the ACDPAC
technique. The oil phases tested were two dimethyl siloxane liquids, silicone oil
A-type and silicone oil B-type. Copyright 1998 Academic Press.
PMID- 9761656
TI - Biosorption of Heavy Metal Ions to Brown Algae, Macrocystis pyrifera,
Kjellmaniella crassiforia, and Undaria pinnatifida.
AB - A fundamental study of the application of brown algae to the aqueous-phase
separation of toxic heavy metals was carried out. The biosorption characteristics
of cadmium and lead ions were determined with brown algae, Macrocystis pyrifera,
Kjellmaniella crassiforia, and Undaria pinnatifida. A metal binding model
proposed by the authors was used for the description of metal binding data. The
results showed that the biosorption of bivalent metal ions to brown algae was due
to bivalent binding to carboxylic groups on alginic acid in brown algae.
Copyright 1998 Academic Press.
PMID- 9761657
TI - Colloidal Particles at Water-Glass Interface: Analyzing Videomicroscopic Data.
AB - Direct videomicroscopic observations provide a powerful tool for investigations
on the deposition of colloidal particles at liquid-solid interfaces. However, the
technique is also capable of producing artefacts caused mainly by limited
resolution. In the present contribution we discuss the possibilities and
limitations of videomicroscopic observations, focussing thereby on an application
example, namely particle deposition from flow in a parallel plate channel in the
presence of a repulsive barrier. We outline algorithms for the determination of
the relevant quantities, indicate the pitfalls, and provide correction formulas.
Special attention is paid to the kinetics of particle release, namely to the
accurate determination of the distribution of the times the particles spend
adhering to the surface. In our example the kinetics of the release is found to
be highly nonexponential, but an adequate fit of the measured distribution of
adhesion times is obtained with a stretched exponential exp[-(betatau)nu], where
nu approximately 0.5 and beta approximately 3 x 10(-5) s-1. Copyright 1998
Academic Press.
PMID- 9761658
TI - Colloidal Particles at Water-Glass Interface: Deposition Kinetics and Surface
Heterogeneity.
AB - Videomicroscopy in combination with evanescent field illumination is applied to
study the sorption of colloidal particles from flow in a parallel plate channel
on a glass surface. The experiments, carried out in the presence of a repulsive
electrostatic barrier, reveal surprisingly complex results: The glass surface,
though optically flat and well cleaned, is not homogeneous, but rather the
sorption occurs at a limited number of preferred sites. Moreover, these sites are
not static: new sites keep appearing at random positions on the observed surface
and disappearing at a rate of kd = 1.3 x 10(-5) s-1. These findings can be
understood within a simple model that takes into account slow but inevitable
dissolution of the glass surface. The bulk glass contains potential adsorbers,
which are continuously being exposed by the dissolution process and act as
transient adsorption sites, before being washed off by the flowing buffer
solution. Copyright 1998 Academic Press.
PMID- 9761659
TI - Colloidal Particles at Solid-Liquid Interfaces: Mechanisms of Desorption
Kinetics.
AB - We study the sorption of colloids on equally charged surfaces. Our focus is on
the time scale from hours to weeks, where adsorption is not an irreversible
process but interplays with (spontaneous) desorption. Using model calculations,
we show how the desorption kinetics is influenced by readsorption, a potential
barrier, a secondary potential minimum, local variation of the potential, and
bond aging. In the experimental part we present results of in situ observation of
the sorption kinetics of polystyrene latex particles onto a glass surface.
Combining the evanescent field method with video microscopy, we were able to
identify the particle arrival and departure times individually and therefrom
determine the adhesion time distribution function. The nonexponentiality of this
function can be explained by a gamma distribution of the potential depth at the
binding sites as well as by logarithmic bond aging. Copyright 1998 Academic
Press.
PMID- 9761660
TI - Experimental Evidence of the Effect of Evaporation-Condensation on Thermal
Marangoni Flows in Aqueous Fatty Alcohol Solutions.
AB - The static surface tension (final sigmae) of aqueous solutions of a fatty alcohol
versus temperature exhibits a minimum. Thus, a temperature gradient which is
created at the free surface of such a solution at temperatures higher than that
of the minimum (final sigmae) should induce a surface flow from the cold area to
the hot one. This was indeed observed even at temperatures much lower than that
of the minimum. A possible explanation is the evaporation of alcohol at the hot
area where the surface tension increases, and its condensation on the cold area
where the surface tension decreases, the alcohol being tranported by the gas
phase. The thickness of the gas phase over the liquid could play a role in the
observed flows. A device was built in which the thickness of the gas phase could
be adjusted. Experiments performed with a 6.2 x 10(-3) m solution of n-heptanol
indicate a lowering of the surface velocity where the thickness of the gas phase
is reduced. Copyright 1998 Academic Press.
PMID- 9761661
TI - The Influence of a Dynamic Stern Layer on the Primary Electroviscous Effect.
AB - The theory developed by Watterson and White (Watterson, I. G., and White, L. R.,
J. Chem. Soc., Faraday Trans. 2 77, 1115 (1981)) to calculate the primary
electroviscous coefficient of a suspension of charged spherical colloidal
particles has been extended, by considering the presence of a dynamic Stern layer
onto the particle surface, following the method developed by Mangelsdorf and
White (Mangelsdorf, C. S., and White, L. R., J. Chem. Soc. Faraday Trans. 80,
2859 (1990)) for electrophoresis. The presence of mobile ions causes the primary
electroviscous coefficient to decrease compared to when the Stern layer ions are
inmobile. A separate dependence of the primary electroviscous coefficient on
kappa-1 (Debye length) and a (particle radius) has been found. Copyright 1998
Academic Press.
PMID- 9761662
TI - Dehydration of Hydrated Bilayer of Dipalmitoylphosphatidylcholine Caused by
Beryllium Ion: Evidence from a Differential Scanning Calorimetry of Bilayer Phase
Transition.
AB - The effect of polyvalent metal ions Be2+, Mg2+, Ca2+, Sr2+, Ba2+, and La3+ on the
phase transition behavior of hydrated bilayer of dipalmitoylphosphatidylcholine
(DPPC) was investigated by differential scanning calorimetry (DSC) in relation to
their ability to induce the aggregation of DPPC vesicles. The addition of the
metal ions other than Be2+ provided DSC thermograms characteristic to a fully
hydrated DPPC bilayer. By the addition of Be2+, the endothermic peak associated
with the bilayer phase transition was shifted to that corresponding to partially
dehydrated DPPC bilayer, which was reported by Kodama et al. (Biochem. Biophys.
Acta 689, 567, 1982). This demonstrates that Be2+ causes dehydration of DPPC head
group in hydrated bilayer and supports the speculation that the unusual property
of Be2+ to induce the aggregation of PC vesicles is attributed to the destruction
of repulsive hydration force due to the partial dehydration of vesicular surface.
Copyright 1998 Academic Press.
PMID- 9761663
TI - The Effect of Polar Head Charge Delocalization on Micellar Aggregation Numbers of
Decylpyridinium Salts, Revisited.
AB - The distribution of charge in an isomeric series of decylpyridinium bromide
surfactants is calculated using the AM1 semiempirical quantum mechanical
molecular model. The aggregation numbers of the surfactants are shown to increase
with a decrease in the residual partial charge in the alkyl tails, suggesting a
change in the packing of the surfactants. The critical micelle concentration
increases with a decrease in the partial charge of the head groups, indicating
increased solubility of the surfactant molecule as charge is more widely
distributed throughout the molecule. Copyright 1998 Academic Press.
PMID- 9761664
TI - The zeta-Potential of Silicone Oil Droplets Dispersed in Aqueous Solutions.
AB - An experimental method to measure the zeta-potential of small liquid droplets
dispersed in another immiscible liquid was presented in this paper. Basically, a
liquid droplet was held stationary in a test cell by applying a proper static
electric field. An existing theory shows that the electrical force experienced by
the droplet can be related to the zeta-potential of the liquid droplet. Thus the
zeta-potential can be determined from the force balance among the electrical
force, the gravitational force, and the buoyancy force being exerted on the
stationary droplet. This electrical suspension method was applied to study the
effects of pH values, ionic features, and concentrations of three electrolytes
and two ionic surfactants on the zeta-potential of the silicone oil (No. 1)
droplets. Copyright 1998 Academic Press.
PMID- 9761665
TI - Characterization of Concentrated Magnetic Colloids by Measurements of Frequency
Dependence of AC Magnetic Susceptibility.
AB - The AC magnetic susceptibility frequency dependence in the range 10 Hz-10 kHz is
used to study concentrated magnetic colloids. Different theoretical and empirical
models are used to describe the frequency dependence. The magnetic analogue of
the Cole-Cole model is found to be most suitable. Values of the model fitting
parameters and the relaxation time distribution provide information about the
dispersability, viscoelastic properties, and interparticle interactions in the
magnetic colloids. Copyright 1998 Academic Press.
PMID- 9761666
TI - Effective Charge on Polymer Colloids Obtained Using a Renormalization Model.
AB - Static light scattering has been used to study the electrostatic interaction
between colloidal particles. Experiments were carried out using a latex with a
very small diameter, allowing structure determination at high particle
concentration. The obtained effective charge characterizing this interaction is
found to be smaller than the bare charge determined from titration. A
renormalization model connecting both values has been used. The agreement between
the renormalized charge and that obtained from scattering data seems to point out
that this model operates well. Copyright 1998 Academic Press.
PMID- 9761667
TI - 13C-NMR Evidence on Amphiphile Lifetime in Reverse (Water-in-Oil) Micelles Formed
by a Poloxamer Block Copolymer.
AB - The dynamics of exchange between amphiphile assembled in reverse (water-in-oil)
micelles and unimer (free in solution) amphiphile were probed by 13C-NMR
spectroscopy in a ternary isothermal system consisting of a poly(ethylene oxide)
poly(propylene oxide) block copolymer (poloxamer), water, and xylene. An upper
bound was obtained for the lifetime of a block copolymer molecule within the
reverse micelle, using the theoretical treatment of exchange phenomena in NMR
which is based on extensions of the Bloch equations. Copyright 1998 Academic
Press.
PMID- 9761668
TI - Telomeric interactions result in the formation of intramolecular circles behaving
as topologically constrained.
AB - The gene-sized macronuclear DNA molecules of hypotrichous ciliates carry
telomeric sequences of homogenous length. Incubation of these molecules at low
concentrations in the presence of monovalent cations (K+, Na+, Cs+) leads to the
formation of intramolecular circles. They can be visualized on one or two
dimensional agarose gels only when KCl is present in the gel. From their
electrophoretic behavior on agarose gels as well as on density gradients it can
be concluded that they are topologically constrained. Digestion of macronuclear
DNA with S1 as well as various exonucleases indicate that both the 3' overhang
and the 5' C-rich strand of the telomeric repeat is involved in these
interactions. Several models of these interactions are discussed.
PMID- 9761669
TI - Implications for function and therapy of a 2.9 A structure of binary-complexed
antithrombin.
AB - The crystal structure of a binary complex of human antithrombin with a peptide of
the same sequence as its reactive loop (P14-P3) has been determined at 2.9 A. The
peptide binds as the middle strand s4A in the A beta-sheet, homologously to that
of the reactive loop in the latent and cleaved forms of antithrombin. Peptide
binding results in the complete expulsion of the hinge region of the loop from
the A beta-sheet although the conformation differs from that of heparin-activated
antithrombin. The 36-fold increase in the rate of reaction of the binary complex
with factor Xa indicates that full loop expulsion alone is not sufficient for
complete heparin activation of antithrombin but that this is also dependent on
the overall conformation of the molecule. Previous studies have demonstrated that
reactive loop peptides can block or reverse the polymerisation of serpins
associated with cirrhosis and thrombosis. The antithrombin binary complex
structure defines the precise localisation of the blocking peptide in a serpin
and provides the basis for rational drug design for mimetics that will prevent
polymerisation in vivo and so ameliorate the associated disease.
PMID- 9761670
TI - Regulation of the Caenorhabditis elegans gut cysteine protease gene cpr-1:
requirement for GATA motifs.
AB - Expression of the Caenorhabditis elegans cysteine protease gene cpr-1 is
regulated both spatially and temporally. In situ hybridisation and Northern blot
analysis have shown that this gene is expressed exclusively in gut cells of all
developmental stages except the embryo. We now show by transgenic transformation
with cpr-1/lac Z reporter gene constructs that a sequence contained within the
cpr-1 5' flanking region can direct this spatial and temporal expression.
Deletion analysis of the cpr-1 promoter indicates that as little as 212 bp of
upstream sequence is sufficient for this expression, although more upstream
sequence may be involved in quantitative regulation of expression. Mutation of
two GATA-like sequence elements at positions -51 and -147 upstream of the
transcription start site ablates all expression, indicating an essential role in
cpr-1 regulation. A concatemer of the cpr-1 -147 GATA motif placed upstream of
minimal promoter/lac Z reporter gene constructs results in strong reporter gene
expression in gut cells of larval stages and also in embryos. Weak expression is
also detected in hypodermal cells. This pattern is reversed in the adult stage
with strong expression in hypodermal cells and weaker expression in gut cells.
Our findings suggest that spatial and temporal regulation of the cpr-1 gene is
complex and involves activation by a GATA-like transcription factor.
PMID- 9761671
TI - Multiple oligomerisation domains in the IS911 transposase: a leucine zipper motif
is essential for activity.
AB - Structure-function relationships involved in oligomerisation of the transposase
OrfAB of the bacterial insertion sequence IS911 have been investigated. Site
directed mutagenesis and sequential deletion coupled with immunoprecipitation
have led to the definition of three regions of the protein capable of promoting
multimerisation. These include a region predicted to assume a coiled-coil
conformation, which is shown to be essential for activity, promoting correct
multimerisation of the N-terminal domain of OrfAB and sequence-specific binding
to the IS911 terminal inverted repeats mediated by this domain. This region
presents the structural and functional characteristics of the leucine zipper
motif described in eukaryotic proteins. The two other regions are located further
towards the C-terminal end of the protein, adjacent to the leucine zipper and in
the region that carries the conserved catalytic DD(35)E motif.
PMID- 9761672
TI - Sequence-dependent extrusion of a small DNA hairpin at the N4 virion RNA
polymerase promoters.
AB - Bacteriophage N4 virion RNA polymerase promoters contain five to seven-base
inverted repeats separated by three bases and centered at position -12 from the
site of transcription initiation. We have previously shown that these inverted
repeats extrude as hairpins at physiological superhelical densities in a Mg(II)
dependent manner. Mg(II)-dependent hairpin extrusion at promoters P1 and P2
displays quantitative differences in reactivity to structural probes at different
DNA superhelical densities, with extrusion at P2 being more favored at low
superhelical density. Analyses of mutant promoters using structure-specific
probes revealed that specific sequences, at the closing base-pair of the hairpin
and at the loop (i.e. 5'-C-GXA-G-3' where X=G, A, T), are required for extrusion
of the small promoter hairpins at physiological superhelical density. The
sequence-dependent requirements for extrusion of the small N4 promoter hairpins
may be generally applicable for other such sequences found both in prokaryotic
and eukaryotic genomes.
PMID- 9761673
TI - Towards the design of rare cutting restriction endonucleases: using directed
evolution to generate variants of EcoRV differing in their substrate specificity
by two orders of magnitude.
AB - The restriction endonuclease EcoRV cleaves DNA highly specifically within GATATC
sequences. In order to create EcoRV variants that have an extended recognition
site we have employed a semi-rational random mutagenesis/selection procedure.
Twenty-two amino acid residues were subjected to random mutagenesis and about 500
EcoRV variants representing three generations of mutants were screened. Among
these some highly active variants that strongly prefer AT-flanked cleavage sites
(e.g. S183A/Q224R, T93S/I103F/S183A/T222S or N97T/S183A/T222S) and others that
prefer GC flanks (e.g. K104N/A181T) were identified. As wild-type EcoRV does not
discriminate between these cleavage sites, the generation of these variants
represents a significant first step towards redesigning EcoRV to become an 8 or
10 bp cutter. Such enzymes, only very rarely found in nature, could be extremely
helpful for the manipulation of large DNA fragments.
PMID- 9761674
TI - The first step: activation of the Semliki Forest virus spike protein precursor
causes a localized conformational change in the trimeric spike.
AB - The structure of the particle formed by the SFVmSQL mutant of Semliki Forest
virus (SFV) has been defined by cryo-electron microscopy and image reconstruction
to a resolution of 21 A. The SQL mutation blocks the cleavage of p62, the
precursor of the spike proteins E2 and E3, which normally occurs in the trans
Golgi. The uncleaved spike protein is insensitive to the low pH treatment that
triggers membrane fusion during entry of the wild-type virus. The conformation of
the spike in the SFVmSQL particle should correspond to that of the inactive
precursor found in the early stages of the secretory pathway. Comparison of this
"precursor" structure with that of the mature, wild-type, virus allows
visualization of the changes that lead to activation, the first step in the
pathway toward fusion. We find that the conformational change in the spike is
dramatic but localized. The projecting domains of the spikes are completely
separated in the precursor and close to generate a cavity in the mature spike.
E1, the fusion peptide-bearing protein, interacts only with the p62 in its own
third of the trimer before cleavage and then collapses to form a trimer of
heterotrimers (E1E2E3)3 surrounding the cavity, poised for the pH-induced
conformational change that leads to fusion. The capsid, transmembrane regions and
the spike skirts (thin layers of protein that link spikes above the membrane)
remain unchanged by cleavage. Similarly, the interactions of the spikes with the
nucleocapsid through the transmembrane domains remain constant. Hence, the
interactions that lead to virus assembly are unaffected by the SFVmSQL mutation.
PMID- 9761675
TI - Surface analysis of the photosystem I complex by electron and atomic force
microscopy.
AB - Two-dimensional (2D) crystals of the photosystem I (PSI) reaction center from
Synechococcus sp. OD24 were analyzed by electron and atomic force microscopy.
Surface relief reconstructions from electron micrographs of freeze-dried
unidirectionally shadowed samples and topographs recorded with the atomic force
microscope (AFM) provided a precise definition of the lumenal and stromal PSI
surfaces. The lumenal surface was composed of four protrusions that surrounded an
indentation. One of the protrusions, the PsaF subunit, was often missing. Removal
of the extrinsic proteins with the AFM stylus exposed the stromal side of the PSI
core, whose surface structure could then be imaged at a resolution better than
1.4 nm. This interfacial surface between core and extrinsic subunits, had a
pseudo-2-fold symmetry and protrusions that correlated with the surface helices e
and e' or were at the sites of putative alpha-helix-connecting loops estimated
from the 4 A map of the complex. The molecular dissection achieved with the AFM,
opens new possibilities to unveil the interfaces between subunits of
supramolecular assemblies.
PMID- 9761676
TI - The nature of antibody heavy chain residue H6 strongly influences the stability
of a VH domain lacking the disulfide bridge.
AB - Monoclonal antibody mAb 03/01/01, directed against the musk odorant traseolide,
carries a serine residue instead of the conserved Cys H92 in the heavy chain
variable domain, and is thus lacking the highly conserved disulfide bridge. We
investigated the energetic consequence of restoring the disulfide bond and the
nature of residue H6 (Glu or Gln), which is poised to interact with Ser H92 in
the recombinant scFv fragment obtained from this antibody. In the scFv fragment
derived from this antibody, the stabilizing effect of Gln H6 over Glu was found
to be as large as the effect of reintroducing the disulfide bond. We have
analyzed the conformation and hydrogen bond pattern of Gln H6 and Glu H6 in
antibodies carrying these residues and suggest mechanisms by which this residue
could contribute to VH domain stability. We also show that the unpaired cysteine
H22 is buried, and conforms to the expected VH structure. The antibody appears to
have acquired two somatic mutations (Ser H52 and Arg H66), which had been
previously characterized as having a positive effect on VH stability. The overall
domain stability is the decisive factor for generating functional, disulfide-free
antibody domains, and several key residues play dominant roles.
PMID- 9761677
TI - Fragile X DNA triplet repeats, (GCC)n, form hairpins with single hydrogen-bonded
cytosine.cytosine mispairs at the CpG sites: isotope-edited nuclear magnetic
resonance spectroscopy on (GCC)n with selective 15N4-labeled cytosine bases.
AB - Here, we provide a direct proof that the formation of hairpins by (GCC)n at the
5'-UTR of the FMR-1 gene offers a mechanism for CpG hypermethylation associated
with the fragile X syndrome. For this, we have performed hetero-nuclear (15N-1H)
magnetic resonance spectroscopy to probe the structure of the CpG sites in the
(GCC)n hairpins that are 15N-labeled at the amino (N4) groups of specific
cytosine bases. Analyses of chemical shift, pH-induced chemical exchange, and NOE
pattern of the (15N-labeled) amino protons of cytosine bases reveal that the
cytosine bases at the CpG sites are intrahelical and well-stacked with the
neighboring G.C base-pairs in the stem of these hairpins and probably form single
hydrogen-bonded C.C mispairs. Measurements of pH-dependent 1H line-width also
demonstrate that the C.C mispairs are more susceptible to open-closure than the
G.C base-pairs. Thus, the Cs at the CpG sites of the (GCC)n hairpin are "flipped
out" more easily to the activated state than those in the corresponding Watson
Crick duplex, (GCC)n. (GGC)n and this makes the hairpin a better target for
methylation by the human methyltransferase, the enzyme that methylates the Cs at
the CpG sites.
PMID- 9761678
TI - Three-dimensional structure of O-acetylserine sulfhydrylase from Salmonella
typhimurium.
AB - The last step in cysteine biosynthesis in enteric bacteria is catalyzed by the
pyridoxal 5'-phosphate-dependent enzyme O-acetylserine sulfhydrylase. Here we
report the crystal structure at 2.2 A resolution of the A-isozyme of O
acetylserine sulfhydrylase isolated from Salmonella typhimurium. O-acetylserine
sulfhydrylase shares the same fold with tryptophan synthase-beta from Salmonella
typhimurium but the sequence identity level is below 20%. There are some major
structural differences: the loops providing the interface to the alpha-subunit in
tryptophan synthase-beta and two surface helices of tryptophan synthase-beta are
missing in O-acetylserine sulfhydrylase. The hydrophobic channel for indole
transport from the alpha to the beta active site of tryptophan synthase-beta is,
not unexpectedly, also absent in O-acetylserine sulfhydrylase. The dimer
interface, on the other hand, is more or less conserved in the two enzymes. The
active site cleft of O-acetylserine sulfhydrylase is wider and therefore more
exposed to the solvent. A possible binding site for the substrate O-acetylserine
is discussed.
PMID- 9761679
TI - Catalytic competence of O-acetylserine sulfhydrylase in the crystal probed by
polarized absorption microspectrophotometry.
AB - The reactions of the pyridoxal 5'-phosphate-dependent enzyme O-acetylserine
sulfhydrylase with the substrate O-acetyl-L-serine and substrate analogs have
been investigated in the crystalline state by single-crystal polarized absorption
microspectrophotometry. This approach has allowed us to examine the catalytic
competence of the enzyme in different crystalline states, one of which was used
to determine the three-dimensional structure; experimental conditions were
defined for the accumulation of catalytic intermediates in the crystal suitable
for crystallographic analyses.O-Acetyl-L-serine reacts with the enzyme in one of
the crystal forms leading via a beta-elimination reaction to the accumulation of
the alpha-aminoacrylate Schiff base, absorbing maximally at 320 and 470 nm, as in
solution. The dissociation constant for the alpha-aminoacrylate Schiff base is in
the millimolar range, 500-fold higher than in solution, suggesting that crystal
lattice interactions may oppose functionally relevant conformational changes. The
dissociation constant exhibits a bell-shaped dependence on pH centered at pH 7.
At this pH the alpha-aminoacrylate species slowly decays with time (30% decrease
in 24 hours). The alpha-aminoacrylate intermediate readily reacts with sodium
azide, an analog of sulfide, the natural nucleophilic agent, to give a new amino
acid and the native enzyme, indicating that the crystalline enzyme catalyzes the
overall beta-replacement reaction as in solution. In other crystal forms,
including that used for the X-ray investigation, O-acetyl-L-serine either has an
even higher dissociation constant or causes crystal damage upon binding. When the
crystalline enzyme reacts with either L-cysteine or L-serine, the external
aldimine intermediate is formed. The dissociation constants for both substrate
analogs are closer to those observed in solution and are modulated by pH as in
solution. Findings demonstrate that O-acetylserine sulfhydrylase is catalytically
competent in the crystal although some regions of the molecule, likely involved
in an open-closed transition induced by O-acetyl-L-serine binding, may have a
limited flexibility. The accumulation in the crystal of both the external
aldimine and the alpha-aminoacrylate intermediate makes feasible their structural
determination and, therefore, the elucidation of the catalytic pathway at the
molecular level.
PMID- 9761680
TI - Unexpected binding mode of tick anticoagulant peptide complexed to bovine factor
Xa.
AB - The structure of recombinant tick anticoagulant peptide (rTAP) complexed to
bovine factor Xa at 3.0 A resolution reveals the structural basis for the
specificity and the high affinity of rTAP. Three N-terminal residues, Tyr501,
Asn502 and Arg503, play a critical role in the complex formation as suggested by
earlier mutagenic studies and the ornithodorin-thrombin complex. Unexpectedly,
the side-chain of Tyr501 is located in the S1 pocket, although factor Xa favors
arginine as a P1 residue. Arg503 is located at the aryl binding pocket and forms
a salt-bridge with Glu97 of factor Xa. The autolysis loop, which is disordered in
the uninhibited factor Xa structure, is involved in the formation of the complex
as a part of the secondary binding site. The C-terminal helix of rTAP interacts
with factor Xa as a secondary binding determinant. The N-terminal residues of
rTAP reorganize during the formation of the factor Xa-rTAP complex from the
conformation found in the solution into an extended conformation. The presence of
the secondary binding site confirms the proposed two-step kinetic mechanism based
on the results of a mutagenesis study.
PMID- 9761681
TI - Structure of the capsid of Pf3 filamentous phage determined from X-ray fibre
diffraction data at 3.1 A resolution.
AB - We have recorded X-ray diffraction patterns at 3.1 A resolution from magnetically
aligned fibres of the Pf3 strain of filamentous bacteriophage (Inovirus). The
patterns are similar to patterns from the higher-temperature form of the Pf1
strain, indicating that the Pf3 and Pf1 virions have the same helix symmetry and
similar protein subunit shape. This is of particular interest, given that the
primary structures of the two protein subunits are quite different; and the
nucleotide/protein subunit ratio in the Pf3 virion is more than twice that in
Pf1, indicating important differences in DNA packaging. We have built a molecular
model of the Pf3 protein capsid based on the model of Pf1, and refined it against
the diffraction data using simulated annealing. The refinement confirms that the
two structures are similar, which may reflect a fundamental motif of alpha-helix
packing. However, there are some differences between the structures: the Pf3
subunit appears to be completely alpha-helical, beginning at the N terminus,
whereas the first few residues of the Pf1 subunit are not helical; and the
structure of the C-terminal region of the Pf3 subunit at the inner surface of the
tubular capsid indicates that DNA/protein interactions in this virion may involve
both aromatic side-chains and positively charged side-chains, whereas those in
the Pf1 virion involve predominantly only the latter. In the course of this work,
we have developed new approaches to refinement and validation of helical
structures with respect to continuous transform fibre diffraction data.
PMID- 9761682
TI - Three-dimensional structure of H-2Dd complexed with an immunodominant peptide
from human immunodeficiency virus envelope glycoprotein 120.
AB - The crystal structure of the mouse major histocompatibility complex (MHC) class I
molecule H-2Dd with an immunodominant peptide, designated P18-I10 (RGPGRAFVTI),
from human immunodeficiency virus envelope glycoprotein 120 was determined at 3.2
A resolution. A novel orientation of the alpha3 domain of Dd relative to the
alpha1/alpha2 domains results in significantly fewer contacts between alpha3 and
beta2-microglobulin compared with other MHC class I proteins. Four out of ten
peptide residues (P2 Gly, P3 Pro, P5 Arg and P10 Ile) are nearly completely
buried in the Dd binding groove. This is consistent with previous findings that
Dd exploits a four-residue binding motif comprising a glycine at P2, a proline at
P3, a positively charged residue at P5, and a C-terminal hydrophobic residue at
P9 or P10. The side-chain of P5 Arg is directed toward the floor of the
predominantly hydrophobic binding groove where it forms two salt bridges and one
hydrogen bond with Dd residue Asp77. The selection of glycine at P2 appears to be
due to a narrowing of the B pocket, relative to that of other class I molecules,
caused by Arg66 whose side-chain folds down into the binding cleft. Residue P3
Pro of P18-I10 occupies part of pocket D, which in Dd is partially split by a
prominent hydrophobic ridge in the floor of the binding groove formed by Trp97
and Trp114. Residues P6 through P9 form a solvent-exposed bulge, with P7 Phe
protruding the most from the binding groove and thereby probably constituting a
major site of interaction with T cell receptors. A comparison of H-2Dd/P18-I10
with other MHC class I/peptide complexes of known structure provides insights
into the possible basis for the specificity of the natural killer cell receptor
Ly-49A for several related class I molecules.
PMID- 9761683
TI - Differences in the intersubunit contacts in triosephosphate isomerase from two
closely related pathogenic trypanosomes.
AB - The aligned amino acid sequences of TIM from Trypanosoma cruzi (TcTIM) and
Trypanosoma brucei (TbTIM) have a positional identity of 68%. The two enzymes
have markedly similar catalytic properties. Agents that interact with their
interface Cys inhibit TcTIM and TbTIM; and those TIMs that lack this Cys (such as
human TIM) are largely or completely insensitive to these agents. The
susceptibility of TcTIM to the agents is approximately 100 times higher than that
of TbTIM. To ascertain the cause of this large difference, the crystal structure
of TcTIM was solved at 1.83 A resolution. The two enzymes are very similar
homodimers. In TcTIM and TbTIM their respective Cys, 15 or 14, forms part of the
dimer interface. In both, the contacts of the Cys with residues of the other
subunit are almost identical. Nevertheless, there are noteworthy differences
between the two; the existence of glutamine 18 in TbTIM instead of glutamic acid
in TcTIM at the beginning of helix 1 decreases the contacts between this portion
of the protein and helix 3 of the other subunit. In addition, TcTIM has proline
at position 24 in the first helix of the TIM barrel; this is absent in the other
TIM. Pro24 disrupts the regular helix arrangement, making the pitch of this helix
1.2 A longer than in TbTIM. When Pro24 of TcTIM was substituted for Glu, the
sensitivity of TcTIM to sulfhydryl reagents increased about fivefold, possibly as
a consequence of an increase in the space between the first portion of helix 1
and helix 3 of the other subunit. Therefore, it may be concluded that the
geometry of the latter region is central in the accessibility to agents that
perturb the interface Cys. In human TIM this region is more compact.
PMID- 9761684
TI - A structural homologue of colipase in black mamba venom revealed by NMR floating
disulphide bridge analysis.
AB - The solution structure of mamba intestinal toxin 1 (MIT1), isolated from
Dendroaspis polylepis polylepis venom, has been determined. This molecule is a
cysteine-rich polypeptide exhibiting no recognised family membership. Resistance
to MIT1 to classical specific endoproteases produced contradictory NMR and
biochemical information concerning disulphide-bridge topology. We have used
distance restraints allowing ambiguous partners between S atoms in combination
with NMR-derived structural information, to correctly determine the disulphide
bridge topology. The resultant solution structure of MIT1, determined to a
resolution of 0.5 A, reveals an unexpectedly similar global fold with respect to
colipase, a protein involved in fatty acid digestion. Colipase exhibits an
analogous resistance to endoprotease activity, indicating for the first time the
possible topological origins of this biochemical property. The biochemical and
structural homology permitted us to propose a mechanically related digestive
function for MIT1 and provides novel information concerning snake venom protein
evolution.
PMID- 9761685
TI - Backbone dynamics of the CDK inhibitor p19(INK4d) studied by 15N NMR relaxation
experiments at two field strengths.
AB - The four members of the INK4 gene family, p16(INK4a), p15(INK4b), p18(INK4c) and
p19(INK4d), are known to bind to and inhibit the closely related cyclin-dependent
kinases CDK4 and CDK6 as part of the regulation of the G1/S transition in the
cell division cycle. Loss of INK4 gene product function, and particularly that of
p16(INK4a), is found in human cancer. 15N NMR relaxation rates of p19(INK4d) were
analyzed using the reduced spectral density mapping method. Most of the backbone
of p19(INK4d) exists in a well-defined structure of limited conformational
flexibility on the nanosecond to picosecond time-scales. Introducing appropriate
scaling to account for the effects of anisotropy, a considerable amount of
exchange broadening was found for several residues throughout the sequence,
especially residues in the second ankyrin repeat and in the beginnings and ends
of loops connecting ankyrin repeats. A possible mode of binding between
p19(INK4d) and CDK4 and CDK6 could therefore involve the loop segments of
p19(INK4d). The average overall correlation time taumeff was determined to be
13.6 ns, reflecting the tendency of p19(INK4d) to aggregate.
PMID- 9761686
TI - The solution structure of a cytotoxic ribonuclease from the oocytes of Rana
catesbeiana (bullfrog).
AB - RC-RNase is a pyrimidine-guanine sequence-specific ribonuclease and a lectin
possessing potent cell cytotoxicity. It was isolated from the oocytes of Rana
catesbeiana (bull frog). From analysis of an extensive set of 1H homonuclear 2D
NMR spectra we have completed the resonance assignments. Determination of the
three-dimensional structure was carried out with the program X-PLOR using a total
of 951 restraints including 814 NMR-derived distances, 61 torsion angles, and 76
hydrogen bond restraints. In the resultant family of 15 best structures, selected
from a total of 150 calculated structures, the root-mean-square deviation from
the average structure for the backbone heavy-atoms involved in well-defined
secondary structure is 0.48 A, while that for all backbone heavy-atoms is 0.91 A.
The structure of RC-RNase consists of three alpha-helices and two triple-stranded
anti-parallel beta-sheets and folds in a kidney-shape, very similar to the X-ray
crystal structure of a homolo gous protein, onconase isolated from Rana pipiens.
We have also investigated the interaction between RC-RNase and two inhibitors,
cytidylyl(2'-->5')guanosine (2',5'-CpG) and 2'-deoxycytidylyl(3'-->5')-2'
deoxyguanosine (3',5'-dCpdG). Based on the ligand-induced chemical shift changes
in RC-RNase and the NOE cross-peaks between RC-RNase and the inhibitors, the key
residues involved in protein-inhibitor interaction have been identified. The
inhibitors were found to bind in a "retro-binding" mode, with the guanine base
bonded to the B1 subsite. The His103 residue was found to occupy the B state with
the imidazole ring pointing away from the active site. The structure coordinates
and the NMR restraints have been deposited in the Brookhaven Protein Data Bank
(1bc4 and 1bc4mr, respectively).
PMID- 9761687
TI - HIV-1 rev nuclear export signal binding peptides isolated by phage display.
AB - The human immunodeficiency virus type 1 (HIV-1) Rev protein is absolutely
essential in the viral replication cycle, where it induces the production of
viral structural proteins. Rev functions in part by inducing the nuclear export
of incompletely spliced mRNA species specified by the presence of an RNA element,
the Rev response element (RRE). Several proteins implicated in RNA processing and
nucleo-cytoplasmic transport have been shown to interact with Rev, however, their
exact roles remain unknown. To map potential protein recognition sites within the
Rev structure, we have screened a phage library, displaying random 15-mer
peptides, and isolated clones exhibiting similar sequences that specifically
interact with Rev. The binding sites on Rev of the corresponding synthetic
peptides were characterised by protein footprinting, involving partial
proteolysis of radioactively end-labelled Rev protein. Two of the peptides
produced a significant footprint within the nuclear export signal of Rev, raising
the possibility that they mimic the binding of cellular protein factors
implicated in nuclear export.
PMID- 9761688
TI - Short elastin-like peptides exhibit the same temperature-induced structural
transitions as elastin polymers: implications for protein engineering.
AB - Elastin is a major protein component of the vascular wall and is responsible for
its unusual elastic properties. Polymers of its repeating VPGVG sequences have
been synthesised and shown to exhibit an inverse temperature transition where, as
temperature rises, the polymer collapses from an extended chain to a beta-spiral
structure with three VPGVG units per turn, each pentamer adopting a type II beta
turn conformation. These studies, however, have not established whether the
temperature-driven conformational change is an intrinsic property of the
individual pentameric sequences or a global, co-operative effect of many
pentamers within the beta-spiral structure. Here, we examine by circular
dichroism the behaviour of elastin-like peptides (VPGVG)n, where n varies between
1 and 5. Remarkably, we find that all lengths of peptide undergo an extended left
and right arrow beta-turn transition with increasing temperature, suggesting that
the induction of the beta-spiral occurs at the level of single pentameric units.
The origin of this effect is a positive DeltaS term for the transition. At 35
degreesC, the average transition midpoint temperature, the value of TDeltaS is
about 15 kcal mol-1. With larger oligomers (n=3), there is only a modest rise in
DeltaS, suggesting that the dominant entropic effect resides within the monomer
and that interactions between these units make only a small contribution to the
energetics of the transition. Charges at the termini, and residue replacements or
additions, regulate the transitions for the short peptides in a manner similar to
that observed for the longer polymers. The behaviour of the same peptides in
trifluoroethanol and SDS solutions is consistent with formation of the beta-turn
being driven by interactions between non-polar groups. The significance of this
behaviour for the rational design of temperature-induced responses in proteins is
discussed.
PMID- 9761689
TI - Equilibrium and kinetics of the folding of equine lysozyme studied by circular
dichroism spectroscopy.
AB - The equilibrium unfolding and the kinetics of unfolding and refolding of equine
lysozyme, a Ca2+-binding protein, were studied by means of circular dichroism
spectra in the far and near-ultraviolet regions. The transition curves of the
guanidine hydrochloride-induced unfolding measured at 230 nm and 292.5 nm, and
for the apo and holo forms of the protein have shown that the unfolding is well
represented by a three-state mechanism in which the molten globule state is
populated as a stable intermediate. The molten globule state of this protein is
more stable and more native-like than that of alpha-lactalbumin, a homologous
protein of equine lysozyme. The kinetic unfolding and refolding of the protein
were induced by concentration jumps of the denaturant and measured by stopped
flow circular dichroism. The observed unfolding and refolding curves both agreed
well with a single-exponential function. However, in the kinetic refolding
reactions below 3 M guanidine hydrochloride, a burst-phase change in the circular
dichroism was present, and the burst-phase intermediate in the kinetic refolding
is shown to be identical with the molten globule state observed in the
equilibrium unfolding. Under a strongly native condition, virtually all the
molecules of equine lysozyme transform the structure from the unfolded state into
the molten globule, and the subsequent refolding takes place from the molten
globule state. The transition state of folding, which may exist between the
molten globule and the native states, was characterized by investigating the
guanidine hydrochloride concentration-dependence of the rate constants of
refolding and unfolding. More than 80% of the hydrophobic surface of the protein
is buried in the transition state, so that it is much closer to the native state
than to the molten globule in which only 36% of the surface is buried in the
interior of the molecule. It is concluded that all the present results are best
explained by a sequential model of protein folding, in which the molten globule
state is an obligatory folding intermediate on the pathway of folding.
PMID- 9761690
TI - Peptide models of local and long-range interactions in the molten globule state
of human alpha-lactalbumin.
AB - alpha-Lactalbumin, a small calcium-binding protein, forms an equilibrium molten
globule state under a variety of conditions. A set of four peptides designed to
probe the role of local interactions and the role of potential long-range
interactions in stabilizing the molten globule of alpha-lactalbumin has been
prepared. The first peptide consists of residues 20 through 36 of human alpha
lactalbumin and includes the entire B-helix. This peptide is unstructured in
solution as judged by CD. The second peptide is derived from residues 101 through
120 and contains both the D and 310 helices. When this peptide is crosslinked via
the native 28 to 111 disulfide to the B-helix peptide, a dramatic increase in
helicity is observed. The crosslinked peptide is monomeric, as judged by
analytical ultracentrifugation. The peptide binds 1-anilinonaphthalene-8
sulphonate (ANS) and the fluorescence emission maximum of the construct is
consistent with partial solvent exposure of the tryptophan residues. The peptide
corresponding to residues 101 to 120 adopts significant non-random structure in
aqueous solution at low pH. Two hydrophobic clusters, one involving residues 101
through 104 and the other residues 115 through 119 have been identified and
characterized by NMR. The hydrophobic cluster formed by residues 101 through 104
is still present in a smaller peptide containing only residues 101 to 111 of
alpha-lactalbumin. The cluster also persists in 6 M urea. A non-native, pH
dependent interaction between the Y103 and H107 side-chains that was previously
identified in the acid-denatured molten globule state was examined. This
interaction was found to be more prevalent at low pH and may therefore be an
example of a local interaction that stabilizes preferentially the acid-induced
molten globule state.
PMID- 9761691
TI - Prediction and structural characterization of an independently folding
substructure in the src SH3 domain.
AB - Previous studies of the conformations of peptides spanning the length of the
alpha-spectrin SH3 domain suggested that SH3 domains lack independently folding
substructures. Using a local structure prediction method based on the I-sites
library of sequence-structure motifs, we identified a seven residue peptide in
the src SH3 domain predicted to adopt a native-like structure, a type II beta
turn bridging unpaired beta-strands, that was not contained intact in any of the
SH3 domain peptides studied earlier. NMR characterization confirmed that the
isolated peptide, FKKGERL, adopts a structure similar to that adopted in the
native protein: the NOE and 3JNHalpha coupling constant patterns were indicative
of a type II beta-turn, and NOEs between the Phe and the Leu side-chains suggest
that they are juxtaposed as in the prediction and the native structure. These
results support the idea that high-confidence I-sites predictions identify
protein segments that are likely to form native-like structures early in folding.
PMID- 9761692
TI - Crystal structure of carbonic anhydrase from Neisseria gonorrhoeae and its
complex with the inhibitor acetazolamide.
AB - The crystal structure of carbonic anhydrase from Neisseria gonorrhoeae has been
solved to a resolution of 1.78 A by molecular replacement using human carbonic
anhydrase II as a template. After refinement the R factor was 17.8%
(Rfree=23.2%). There are two molecules per asymmetric unit (space group P21), but
they have essentially identical structures. The fold of the N. gonorrhoeae enzyme
is very similar to that of human isozyme II; 192 residues, 74 of which are
identical in the two enzymes, have equivalent positions in the three-dimensional
structures. This corresponds to 85% of the entire polypeptide chain of the
bacterial enzyme. The only two cysteine residues in the bacterial enzyme, which
has a periplasmic location in the cell, are connected by a disulfide bond. Most
of the secondary structure elements present in human isozyme II are retained in
N. gonorrhoeae carbonic anhydrase, but there are also differences, particularly
in the few helical regions. Long deletions in the bacterial enzyme relative to
human isozyme II have resulted in a considerable shortening of three surface
loops. One of these deletions, corresponding to residues 128 to 139 in the human
enzyme, leads to a widening of the entrance to the hydrophobic part of the active
site cavity. Practically all the amino acid residues in the active site of human
isozyme II are conserved in the N. gonorrhoeae enzyme and have similar structural
positions. However, the imidazole ring of a histidine residue, which has been
shown to function as a proton shuttle in the catalytic mechanism of the human
enzyme, interacts with an extraneous entity, which has tentatively been
identified as a 2-mercaptoethanol molecule from the crystallization medium. When
this entity is removed by soaking the crystal in a different medium, the side
chain of His66 becomes quite mobile. The structure of a complex with the
sulfonamide inhibitor, acetazolamide, has also been determined. Its position in
the active site is very similar to that observed in human carbonic anhydrase II.
PMID- 9761694
TI - The wallace brey symposium
PMID- 9761693
TI - Structural and functional roles of heme binding module in globin proteins:
identification of the segment regulating the heme binding structure.
AB - To investigate structural and functional significance of a newly proposed
structural unit in globins, the "heme binding module", we synthesized a "heme
binding module"-substituted chimeric globin and characterized its function and
structure. In our previous study we proposed that the heme binding module,
corresponding to the segment from Leu(F1) to Phe(G5) in hemoglobin alpha-subunit,
plays a key role in constructing the heme proximal structure in globins. The
replacement of the heme binding module in myoglobin with that of hemoglobin alpha
subunit converted the absorption spectra into that of the alpha-subunit, and, in
the resonance Raman spectra, the vibration mode characteristic of myoglobin
completely disappeared after the module replacement. The hyperfine-shifted NMR
resonances for the cyanide-bound form of the module-substituted myoglobin also
revealed that the orientation of the axial histidine is close to that of the
alpha-subunit rather than that of myoglobin, while the deviations of the
resonance positions of the NMR signals from the amino acid residues located in
the distal site were subtle, supporting the preferential structural alterations
in the heme proximal site. The present finding for the structural alterations in
the module-substituted myoglobin confirms that the heme binding module can be a
segment regulating the heme proximal structure in globin proteins.
PMID- 9761695
TI - Intravascular and intracellular hepatic relaxivities of superparamagnetic
particles: an isolated and perfused organ pharmacokinetics study.
AB - The relative contributions of intravascular and intracellular compartments to the
proton transverse relaxation of the isolated and excised rat liver were
determined during the phagocytosis of superparamagnetic particles. The evolution
of the proton transverse magnetization of the organ perfused with increasing
doses of starch-coated magnetic microspheres was followed up using a Carr-Purcell
Meiboom-Gill sequence with various echo times. From the multiexponential fit of
the echo train, the amplitudes and the relaxation rates R2 of the liver tissue
were obtained. The results clearly indicate that shortly after contrast medium
administration, an internalization takes place which can be followed by the rapid
and biphasic evolution of the transverse relaxation rate of the water protons. A
very fast decaying component looking like an initial loss of the magnetization is
observed together with an increase of the relaxation rate of the remaining water
tissue. This regime is strongly dependent on both the echo time and the iron
concentration, a behavior characteristic of the agglomeration of magnetic
particles. The examination of the liver tissues by electron microscopy shows that
this clustering arises in cytoplasmic vacuoles.
PMID- 9761696
TI - Image-based reduction of artifacts in multishot echo-planar imaging.
AB - The method to reduce the ghost artifact in echo-planar imaging (EPI) using a
phase correction derived from the image data (M. H. Buonocore and L. Gao, Magn.
Reson. Med. 38, 89 (1997)) is generalized to multishot (interleaved) EPI, where
the artifact takes the form of multiple ghosts. The method is shown to be much
more sensitive to noise when applied to standard interleaved data than is the
case with single-shot EPI, because the calculation must be based on high-order
ghosts of low intensity. A modified interleaving scheme is proposed for multishot
EPI in which the initial trajectory direction alternates in consecutive shots and
the number of shots is odd. With this scheme, only a single ghost shifted by one
half of the field of view appears just as in the single-shot EPI, and the image
based phase correction can be applied with the usual sensitivity to noise.
PMID- 9761697
TI - In vivo 3D localized 13C spectroscopy using modified INEPT and DEPT.
AB - The 3D localized 13C spectroscopy methods LINEPT and LODEPT, which are
modifications of INEPT and DEPT, are proposed. As long as a 13C inversion pulse
(180-degree pulse) is applied at 1/(4J) before the proton echo time in LINEPT and
a 13C excitation pulse (90-degree pulse) is applied at 1/(2J) before the proton
echo time in LODEPT, the proton echo time can be set to any value longer than
1/(2J) in LINEPT and longer than 1/J in LODEPT. As a result, the proton and the
13C pulses can be applied separately and these proton pulses can be made slice
selective pulses. These localization features of LINEPT and LODEPT were evaluated
using a phantom consisting of a cylinder filled with ethanol placed inside
another cylinder filled with oil, and localized ethanol spectra could be
obtained. In vivo 3D localized 13C spectra from the brain of a monkey could be
obtained using decoupled LINEPT, and glutamate C-4 appeared directly after the
administration of glucose C-1, followed by the appearance of glutamate C-2, C-3
and glutamine C-2, C-3, C-4.
PMID- 9761698
TI - Evolution strategy optimization for selective pulses in NMR
AB - We present a first set of improved selective pulses, obtained with a numerical
technique similar to the one proposed by Geen and Freeman. The novelty is
essentially a robust and efficient "evolution strategy" which consistently leads,
in a matter of minutes, to "solutions" better than those published so far. The
other two ingredients are a "cost function," which includes contributions from
peak and average radiofrequency power, and some understanding of the peculiar
requirements of each type of pulse. For example, good solutions for self
refocusing pulses and "negative phase excitation pulses" (which yield a maximum
signal well after the end of the pulse) are found, as may have been predicted,
among amplitude modulated pulses with 270 degrees tip angles. Emphasis is given
to the search for solutions with low RF power for selective excitation,
saturation, and inversion pulses. Experimental verification of accuracy and power
requirements of the pulses has been performed with a 4.7 T Sisco imager.
Copyright 1998 Academic Press.
PMID- 9761699
TI - A high-precision carbon-13 shift thermometer for the temperature range 100-300 K
AB - The first carbon-13 shift thermometer for the temperature range of 100-300 K is
based on the very rapid equilibration of a pair of semibullvalene valence
tautomers. The temperature dependence of the equilibrium constant is reflected in
strongly temperature-dependent shift differences Deltadelta between averaged
signals, e.g., d(Deltadelta)/dT = 0.051 ppm K-1 at 300, 0.087 ppm K-1 at 200, and
0. 175 ppm K-1 at 110 K for the quaternary carbon atoms C2 and C6. At 37
temperatures T, which were measured with calibrated platinum resistance
thermometers, shift differences Deltadelta were taken from nondecoupled carbon-13
spectra recorded from solutions of 1 in mixtures of chlorodifluoromethane and
deuterated dimethyl ether without spinning. The least-squares fit of these
Deltadelta vs T data to a polynomial equation of the fourth degree (Eq. [5], r2 =
0. 9999) allows the calculation of temperatures from measured shift differences
with a standard deviation of 0.46 K and an estimated error of about 1 K. The
heating effects of WALTZ-16 decoupling and the influence of solvents on
Deltadelta are investigated. A comparison with existing NMR thermometers
demonstrates the superior performance of the new carbon-13 shift thermometer with
respect to precision and the accessible temperature range. Copyright 1998
Academic Press.
PMID- 9761700
TI - Diffusion measurements using radiofrequency field gradient: artifacts, remedies,
practical hints
AB - The two major advantages of experiments carried out with radiofrequency (RF)
field-gradient NMR are the instrumental simplicity and the insensitivity to
background static magnetic field gradients. These features combined with large RF
gradients, which became available only recently, should make this technique
especially attractive for molecular translational diffusion studies. However, a
critical evaluation of the method shows that under some circumstances (small
and/or heterogeneous samples, weak diffusion coefficients, very short relaxation
times) the quality of measurements may be affected by a number of artifacts.
Their origin has been investigated and several remedies have been considered; in
particular, a new improved sequence is presented. The success of various
experimental tests demonstrates the efficiency of the proposed solutions which
thus open the way to much wider application fields. Copyright 1998 Academic
Press.
PMID- 9761702
TI - Direct determination of motional correlation times by 1D MAS and 2D exchange NMR
techniques
AB - One- and two-dimensional static and magic-angle spinning (MAS) exchange NMR
experiments for quantifying slow (tauc > 1 ms) molecular reorientation dynamics
are analyzed, emphasizing the extent to which motional correlation times can be
extracted directly from the experimental data. The static two-dimensional (2D)
exchange NMR experiment provides geometric information, as well as exchange time
scales via straightforward and model-free application of Legendre-type
orientational autocorrelation functions, particularly for axially symmetric
interaction tensors, as often encountered in solid-state 2H and 13C NMR. Under
conditions of MAS, increased sensitivity yields higher signal-to-noise spectra,
with concomitant improvement in the precision and speed of correlation time
measurements, although at the expense of reduced angular (geometric) resolution.
For random jump motions, one-dimensional (1D) exchange-induced sidebands (EIS)
13C NMR and the recently developed ODESSA and time-reverse ODESSA experiments
complement the static and MAS two-dimensional exchange NMR experiments by
providing faster means of obtaining motional correlation times. For each of these
experiments, the correlation time of a dynamic process may be obtained from a
simple exponential fit to the integrated peak intensities measured as a function
of mixing time. This is demonstrated on polycrystalline dimethylsulfone, where
the reorientation rates from EIS, ODESSA, time-reverse ODESSA, and 2D exchange
are shown to be equivalent and consistent with literature values. In the
analysis, the advantages and limitations of the different methods are compared
and discussed. Copyright 1998 Academic Press.
PMID- 9761701
TI - 2D CP/MAS 13C isotropic chemical shift correlation established by 1H spin
diffusion.
AB - A new 2D solid-state CP/MAS 13C NMR exchange experiment for through-space
isotropic chemical shift correlation is proposed and demonstrated. Through-space
correlation is established via a second cross polarization from 13C to 1H and
subsequent 1H spin diffusion. A third cross polarization results in the final 13C
13C isotropic chemical shift correlation. The 1H spin diffusion time is a
variable parameter allowing different mean square magnetization displacements to
be probed. Experimental results on mixtures of differently 13C-labeled alanine
and polyethylene indicate that this site-selective 2D technique can be used to
characterize domain sizes and proximities over a wide range of length scales (1
200 nm) in solids such as polymers or biological materials.
PMID- 9761703
TI - Fourier reconstruction as a valid alternative to filtered back projection in
iterative applications: implementation of Fourier spectral spatial EPR imaging.
AB - The qualitative equivalence between the Fourier reconstruction (FR) algorithm and
the filtered back projection (FBP) algorithm is demonstrated when all the
different phase errors that can occur in FR are eliminated. The causes of phase
errors are underlined and methods to eliminate them are presented. The practical
comparison between FR and FBP has been evaluated on a numerical test image and
the results are reported, demonstrating the qualitative equivalence. FR has the
advantage of being very computationally efficient. In fact, the time spent to
obtain the FR image was 1/20 of that used to obtain the FBP image. Because of the
computational efficiency of FR and the good quality of the results obtained, an
iterative version of FR has been used to implement the spectral-spatial imaging
(SSI) algorithm in the field of electron paramagnetic resonance imaging (EPRI).
An experimental example, demonstrating its good performance, is reported.
PMID- 9761705
TI - A new method for the determination of the dynamic isotope effect and the
deuterium quadrupole coupling constant in liquids
AB - Using a self-consistent NMR method, it is now possible to determine both the
deuterium quadrupole coupling constant as well as the rotational dynamic isotope
effect in liquids. We successfully tested the method on benzene for temperatures
between 280 K and 293 K. The average value of 185(3) kHz for the coupling
constant is compared with measurements in solid state and gas phase. As might be
expected for liquids without hydrogen bonds, no difference can be detected. A
rotational dynamic isotope effect of 6(3)% is observed. This value is
significantly smaller than 20(5)%, the only other result reported in the
literature. The results are corrected for the influence of vibrational motion.
Copyright 1998 Academic Press.
PMID- 9761704
TI - Localized spectroscopy from anatomically matched compartments: improved
sensitivity and localization for cardiac 31P MRS in humans.
AB - Several pioneering studies have demonstrated that localized 31P NMR spectroscopy
of the human heart might become an important diagnostic tool in cardiology. The
main limitation is due to the low sensitivity of these experiments, allowing only
crude spatial resolution. We have implemented a three-dimensional version of
SLOOP ("spectral localization with optimal pointspread function") on a clinical
instrument. SLOOP takes advantage of all available a priori information to match
the size and the shape of the sensitive volumes to the anatomical structures in
the examined subject. Thus, SLOOP reduces the contamination from adjacent organs
and improves the sensitivity compared to conventional techniques such as ISIS or
chemical shift imaging (CSI). Initial studies were performed on six healthy
volunteers at 1.5 T. The good localization properties are demonstrated by the
absence of resonances from blood in the heart spectra, and by PCr-free spectra
from the liver. Compared to conventional CSI, the signal-to-noise ratio of the
SLOOP heart spectra was improved by approximately 30%. Taking into account the
varying excitation angle in the inhomogeneous B1 field of the surface coil, the
SLOOP model computes the local spin saturation at every point in space.
Therefore, no global saturation correction is required in the quantitative
evaluation of local spectra. In this study, we found a PCr/gamma-ATP ratio in the
left ventricular wall of 1.90 +/- 0.33 (mean +/- standard deviation).
PMID- 9761706
TI - Improved estimation of CSA-dipolar coupling cross-correlation rates from
laboratory-frame relaxation experiments
AB - We have investigated the underlying assumptions in estimating cross-correlation
rates between chemical shift anisotropy (CSA) and dipolar coupling mechanisms in
a scalar-coupled two-spin IS system, from laboratory frame relaxation
experiments. It has been shown that for an arbitrary relaxation delay, the
difference in relaxation rates of the individual components of an in-phase (or
antiphase) doublet is not related to the CSA-dipolar coupling cross-correlation
rate in a simple way. This is especially true in the case where the difference in
the decay rates of the in-phase and antiphase terms of the density matrix becomes
comparable to the magnitude of the scalar coupling between the two spins.
Improved means of extracting cross-correlation rates in these cases are
presented. Copyright 1998 Academic Press.
PMID- 9761707
TI - A vector model of adiabatic decoupling
AB - A vector model of adiabatic decoupling is enunciated for an IS-coupled system of
two spin-(1/2) heteronuclei in the high-power limit of ideal adiabatic pulses.
The observed S-spin magnetization evolves according to a time-dependent coupling
that scales as the z component of an I-spin vector which evolves due to the
applied decoupling irradiation. Simple analytical expressions are derived both on
and off resonance for the reduced coupling during an ideal sech/tanh inversion
pulse and for the resulting signal when either in-phase or antiphase
magnetization is present at the start of decoupling. The resulting model allows
one to readily envision decoupling experiments, make accurate estimates of
sideband intensity, and assess the relative performance of different decoupling
schemes. The utility of the model is further demonstrated by applying it to
several recently proposed methods for reducing sidebands. In the limit of ideal
adiabatic pulses, the predictions of the vector model are almost identical to
those of quantum mechanics. At the lower RF power levels used in practical
adiabatic decoupling applications, where the pulses are no longer perfectly
adiabatic, phase cycles are employed to achieve performance that approximates the
ideal limits derived here, so the vector model is more generally applicable, as
well. These limits establish standards for future determination of the most
efficient parameters for practical applications of broadband adiabatic decoupling
in a single transient. Copyright 1998 Academic Press.
PMID- 9761708
TI - Calibration of STUD+ parameters to achieve optimally efficient broadband
adiabatic decoupling in a single transient
AB - To provide the most efficient conditions for spin decoupling with least RF power,
master calibration curves are provided for the maximum centerband amplitude, and
the minimum amplitude for the largest cycling sideband, resulting from STUD+
adiabatic decoupling applied during a single free induction decay. The principal
curve is defined as a function of the four most critical experimental input
parameters: the maximum amplitude of the RF field, RFmax, the length of the
sech/tanh pulse, Tp, the extent of the frequency sweep, bwdth, and the coupling
constant, Jo. Less critical parameters, the effective (or actual) decoupled
bandwidth, bweff, and the sech/tanh truncation factor, beta, which become more
important as bwdth is decreased, are calibrated in separate curves. The relative
importance of nine additional factors in determining optimal decoupling
performance in a single transient are considered. Specific parameters for
efficient adiabatic decoupling can be determined via a set of four equations
which will be most useful for 13C decoupling, covering the range of one-bond
13C1H coupling constants from 125 to 225 Hz, and decoupled bandwidths of 7 to 100
kHz, with a bandwidth of 100 kHz being the requirement for a 2 GHz spectrometer.
The four equations are derived from a recent vector model of adiabatic
decoupling, and experiment, supported by computer simulations. The vector model
predicts an inverse linear relation between the centerband and maximum sideband
amplitudes, and it predicts a simple parabolic relationship between maximum
sideband amplitude and the product JoTp. The ratio bwdth/(RFmax)2 can be viewed
as a characteristic time scale, tauc, affecting sideband levels, with tauc
approximately Tp giving the most efficient STUD+ decoupling, as suggested by the
adiabatic condition. Functional relationships between bwdth and less critical
parameters, bweff and beta, for efficient decoupling can be derived from Bloch
equation calculations of the inversion profile for a single sech/tanh pulse.
Residual splitting of the centerband, normally associated with incomplete or
inefficient decoupling, is not seen in sech/tanh decoupling and therefore cannot
be used as a measure of adiabatic decoupling efficiency. The calibrated
experimental performance levels achieved in this study are within 20% of
theoretical performance levels derived previously for ideal sech/tanh decoupling
at high power, indicating a small scope for further improvement at practical RF
power levels. The optimization procedures employed here will be generally
applicable to any good combination of adiabatic inversion pulse and phase cycle.
Copyright 1998 Academic Press.
PMID- 9761709
TI - Unambiguous correlations of backbone amide and aliphatic gamma resonances in
deuterated proteins.
AB - Two 3D NMR pulse sequences that correlate aliphatic gamma carbon resonance
frequencies to amide proton and nitrogen chemical shifts in perdeuterated
proteins are presented. The HN(COCACB)CG provides only interresidue
connectivities (NH(i) and Cgamma(i-1)) while the HN(CACB)CG detects both the
inter- and intraresidue (NH(i) and Cgamma(i) or Cgamma(i-1)) correlations. These
two experiments are useful for sequential assignments and the identification of
residue type from the Cgamma shifts. Spectra acquired on a perdeuterated 53-kDa
protein illustrate the sensitivity and utility of these experiments.
PMID- 9761710
TI - Pulsed field gradient selection in two-dimensional magic angle spinning NMR
spectroscopy of dipolar solids
AB - The utility of gradient selection in MAS spectroscopy of dipolar solids is
explored in two examples. In the first, rotor-synchronized gradients of
appropriate strength and duration are applied to select 1H double-quantum
coherences. The resulting DQ MAS spectrum of adamantane is compared with that
acquired by the corresponding phase-cycling technique. As a second example, a 1H
2D exchange MAS experiment is performed on an elastomer sample. In this
experiment, a gradient is applied to remove undesired coherences that would
otherwise distort the spectrum for short mixing times. The diagonal-peak
intensities in the resulting spectrum show a linear decrease with increasing
mixing time indicating cross-relaxation by slow chain motions as the relevant
process. Both types of experiments demonstrate the potential of gradient
selection techniques for MAS spectroscopy of dipolar solids. Copyright 1998
Academic Press.
PMID- 9761711
TI - High magnetic field consequences on the NMR hyperfine shifts in solution
AB - Pseudocontact shifts arise from the isotropic reorientational average of the
dipolar coupling between unpaired electron and nuclei, in the presence of
magnetic susceptibility anisotropy. The effect of residual orientation due to
high magnetic fields on pseudocontact shifts is evaluated here. The effect is
found to be smaller and of opposite sign with respect to another novel effect of
high magnetic fields on hyperfine shifts due to saturation of the electron spin
magnetic moment as described by the Brillouin equation. Copyright 1998 Academic
Press.
PMID- 9761713
TI - Meetings calendar
PMID- 9761712
TI - Measurement of dipolar couplings for methylene and methyl sites in weakly
oriented macromolecules and their use in structure determination.
AB - A simple and effective method is described for simultaneously measuring dipolar
couplings for methine, methylene, and methyl groups in weakly oriented
macromolecules. The method is a J-modulated 3D version of the well-known [1H-13C]
CT-HSQC experiment, from which the J and dipolar information are most accurately
extracted by using time-domain fitting in the third, constant-time dimension. For
CH2-sites, the method generally yields only the sum of the two individual 13C-1H
couplings. Structure calculations are carried out by minimizing the deviation
between the measured sum, and the sum predicted for each methylene on the basis
of the structure. For rapidly spinning methyl groups the dipolar contribution to
the splitting of the outer 13C quartet components can be used directly to
constrain the orientation of the C-CH3 bond. Measured sidechain dipolar couplings
are in good agreement with an ensemble of NMR structures calculated without use
of these couplings.
PMID- 9761715
TI - The cysteine-string domain of the secretory vesicle cysteine-string protein is
required for membrane targeting.
AB - The post-translational addition of palmitic acid residues to cysteine-string
protein (Csp) was originally thought to form the basis for membrane association
of this secretory-vesicle protein. However, subsequent work showed that chemical
depalmitoylation of Csp does not result in its release from membranes. We have
confirmed these findings and employed [3H]palmitate labelling of PC12 cells to
demonstrate that Csp1 remains associated with membranes following the complete
removal of palmitic acid residues. Although palmitoylation is not essential for
the stable membrane association of Csp, its role in membrane targeting has not
been assessed. To examine this, we constructed a Csp mutant protein with seven
cysteines replaced by serines in the cysteine-string domain. In contrast to wild
type Csps, this mutant protein was not targeted to membranes when expressed in
PC12 or HeLa cells. We conclude that although a palmitoylated cysteine-string
domain is not required for stable membrane association of Csp, it is essential
for initial membrane targeting.
PMID- 9761716
TI - Circe's haemoglobins, pig-human hybrids: functional characterization and
structural considerations.
AB - We report the isolation and the functional characterization of alpha and beta
chains from pig (Sus scropha domesticus) haemoglobin, as well as of the pig-human
hybrid haemoglobins, alpha2(h)beta2(p) and alpha2(p)beta2(h) (i.e. Circe's
haemoglobins), obtained by mixing the purified alpha and beta pig chains
respectively with the corresponding partner human chains. Their functional
properties have been compared with those of both parental haemoglobins in order
to obtain information on the role of the different subunits and of their inter
relationships, both at the structural and functional levels. The results indicate
that the functional properties of both hybrids are closer to those of the
parental haemoglobin that provides the beta chains, confirming the major role of
the beta chains in determining the oxygen affinity and the modulation mechanisms
of the tetrameric molecule. This is supported by the thermodynamic properties,
since the very low DeltaH of oxygen binding that characterizes pig haemoglobin
and the alpha2(h)beta2(p) hybrid haemoglobin may be taken as the reflection of
specific structural properties of pig beta chain.
PMID- 9761714
TI - Genetic engineering in mice: impact on insulin signalling and action.
AB - The expression of a number of genes encoding key players in insulin signalling
and action, including insulin, insulin receptor (IR), downstream signalling
molecules such as insulin receptor substrate-1 (IRS-1) and IRS-2, glucose
transporters (GLUT4, GLUT2) and important metabolic enzymes such as glucokinase,
has now been altered in transgenic or knockout mice. Such mice presented with
phenotypes ranging from mild defects, revealing complementarity between key
molecules or pathways, to severe diabetes with ketoacidosis and early postnatal
death. Insulin action could also be improved by overproduction of proteins acting
at regulatory steps. The development of diabetes by combining mutations, which
alone do not lead to major metabolic alterations, validated the 'diabetogenes'
concept of non-insulin-dependent diabetes mellitus. Genes encoding insulin-like
growth factors (IGF-I and IGF-II) and their type I receptor (IGF-IR) have also
been disrupted. It appears that although IR and IGF-IR are both capable of
metabolic and mitogenic signalling, they are not fully redundant. However, IR
could replace IGF-IR if efficiently activated by IGF-II. Studies with cell lines
lacking IR or IGF-IR lend support to such conclusions. Concerning the issues of
specificity and redundancy, studies with cell lines derived from IRS-1-deficient
mice showed that IRS-1 and IRS-2 are also not completely interchangeable.
PMID- 9761717
TI - Purification and characterization of autophagosomes from rat hepatocytes.
AB - To investigate the properties and intracellular origin of autophagosomes, a
procedure for the purification and isolation of these organelles from rat liver
has been developed. Isolated hepatocytes were incubated with vinblastine to
induce autophagosome accumulation; the cells were then homogenized and treated
with the cathepsin C substrate glycyl-l-phenylalanine 2-naphthylamide to cause
osmotic disruption of the lysosomes. Nuclei were removed by differential
centrifugation, and the postnuclear supernatant was fractionated on a
discontinuous Nycodenz density gradient. The autophagosomes, recognized by their
content of autophagocytosed lactate dehydrogenase (LDH), could be recovered in an
intermediate-density fraction, free from cytosol and mitochondria. Finally, the
autophagosomes were separated from the endoplasmic reticulum and other membranous
elements by centrifugation in a Percoll colloidal density gradient, followed by
flotation in iodixanol to remove the Percoll particles. The final autophagosome
preparation represented a 24-fold purification of autophagocytosed LDH relative
to intact cells, with a 12% recovery. The purified autophagosomes contained
sequestered cytoplasm with a normal ultrastructure, including mitochondria,
peroxisomes and endoplasmic reticulum in the same proportions as in intact cells.
However, immunoblotting indicated a relative absence of cytoskeletal elements
(tubulin, actin and cytokeratin), which may evade autophagic sequestration. The
autophagosomes showed no enrichment in protein markers typical of lysosomes (acid
phosphatase, cathepsin B, lysosomal glycoprotein of 120 kDa), endosomes (early
endosome-associated protein 1, cation-independent mannose 6-phosphate receptor,
asialoglycoprotein receptor) or endoplasmic reticulum (esterase, glucose
regulated protein of 78 kDa, protein disulphide isomerase), suggesting that the
sequestering membranes are not derived directly from any of these organelles, but
rather represent unique organelles (phagophores).
PMID- 9761718
TI - The insertion of human apolipoprotein H into phospholipid membranes: a monolayer
study.
AB - Apolipoprotein H (ApoH) is a plasma glycoprotein isolated from human serum. The
interactions of ApoH with lipid membrane were reported to be essential for its
physiological and pathogenic roles. In this paper we studied the ability of ApoH
to insert into phospholipid membranes using the monolayer approach. The results
show that ApoH is surface active and can insert into the lipid monolayers. The
insertion ability of ApoH is stronger when a higher content of negatively charged
lipids is present in the membrane. The acidic-pH and low-ionic-strength
conditions will also enhance ApoH insertion, but these factors may not have much
influence on the final insertion ability of ApoH, suggesting that, in the
mechanism of ApoH insertion, not only electrostatic forces, but also hydrophobic
interactions, are evidently involved. Modification by heat inactivation and
reduction/alkylation does not change the critical insertion pressure (pic) of
ApoH, suggesting a stable domain, maybe a linear sequence motif, but not the
native three-dimensional structure of ApoH, is responsible for its insertion. The
extent to which insertion of ApoH into phospholipid membranes may facilitate the
'immune cleaning' of plasma liposomes is discussed.
PMID- 9761719
TI - Oxidation of DNA bases, deoxyribonucleosides and homopolymers by peroxyl
radicals.
AB - DNA base oxidation is considered to be a key event associated with disease
initiation and progression in humans. Peroxyl radicals (ROO. ) are important
oxidants found in cells whose ability to react with the DNA bases has not been
characterized extensively. In this paper, the products resulting from ROO.
oxidation of the DNA bases are determined by gas chromatography/MS in comparison
with authentic standards. ROO. radicals oxidize adenine and guanine to their 8
hydroxy derivatives, which are considered biomarkers of hydroxyl radical (HO.)
oxidations in cells. ROO. radicals also oxidize adenine to its hydroxylamine, a
previously unidentified product. ROO. radicals oxidize cytosine and thymine to
the monohydroxy and dihydroxy derivatives that are formed by oxidative damage in
cells. Identical ROO. oxidation profiles are observed for each base when exposed
as deoxyribonucleosides, monohomopolymers and base-paired dihomopolymers. These
results have significance for the development, utilization and interpretation of
DNA base-derived biomarkers of oxidative damage associated with disease
initiation and propagation, and support the idea that the mutagenic potential of
N-oxidized bases, when generated in cellular DNA, will require careful
evaluation. Adenine hydroxylamine is proposed as a specific molecular probe for
the activity of ROO. in cellular systems.
PMID- 9761720
TI - Stimulation of gene expression in neonatal rat ventricular myocytes by Ras is
mediated by Ral guanine nucleotide dissociation stimulator (Ral.GDS) and
phosphatidylinositol 3-kinase in addition to Raf.
AB - Treatment of cultured neonatal ventricular myocytes with oncogenic Ras increases
their size and stimulates the re-expression of genes which are normally
restricted to the fetal stage of ventricular development, including atrial
natriuretic factor (ANF) and skeletal muscle (SkM)-alpha-actin. To determine
which signalling pathways mediate these responses, myocytes were transfected with
oncogenic (V12) Ras mutants which interact selectively with different effectors
and their effects on luciferase (LUX) reporter plasmids were examined. V12 human
Ras (V12HRas), itself, activated ANF-LUX 9. 6-fold, whereas mutants of V12HRas,
which selectively stimulate Ral guanine nucleotide dissociation stimulator
(Ral.GDS) (E37G), c-Raf (D38E) and phosphatidylinositol 3-kinase (PI-3-K; Y40C)
enhanced ANF-LUX expression 3.0-, 3.7- and 1.7-fold respectively. The full
response of ANF-LUX to V12HRas was restored by using a combination of the
individual effector domain mutants. Likewise, SkM-alpha-actin-LUX expression was
activated 12.0-, 3.5-, 4.5- and 3. 0-fold by V12HRas, E37G, D38E and Y40C
respectively, and a similar pattern of activation was also observed using a c-fos
serum-response element-LUX reporter gene. Cell size was also increased by each of
the mutants, but simultaneous expression of all three mutant constructs was
needed to reconstitute the full effect of V12HRas on cell size (50% increase).
Transfection with a constitutively active mutant of PI-3-K (p110K227E) stimulated
ANF-LUX, SkM-alpha-actin-LUX, c-fos-serum-response element-LUX and Rous sarcoma
virus-LUX by 3.1-, 3.2-, 2.1- and 2.9-fold respectively, but the co-transfected
cytomegalovirus-beta-galactosidase reporter gene was activated to a similar
extent (1.9-fold). These results suggest that Raf, Ral.GDS and PI-3-K can all
transduce transcriptional responses to V12HRas, but that the specific induction
of genes associated with the hypertrophic response is not mediated through PI-3
K.
PMID- 9761721
TI - Modulation of RGD sequence motifs regulates disintegrin recognition of alphaIIb
beta3 and alpha5 beta1 integrin complexes. Replacement of elegantin alanine-50
with proline, N-terminal to the RGD sequence, diminishes recognition of the
alpha5 beta1 complex with restoration induced by Mn2+ cation.
AB - Several recent studies have demonstrated that the amino acid residues flanking
the RGD sequence of high-affinity ligands modulate their specificity of
interaction with integrin complexes. The present study has addressed the role of
the residues flanking the RGD sequence in regulating the recognition by
disintegrin of the alphaIIb beta3 and alpha5beta1 complexes by construction of a
panel of recombinant molecules of Elegantin (the platelet aggregation inhibitor
from the venom of Trimerasurus elegans) expressing specific RGD sequence motifs.
Wild-type Elegantin (ARGDNP) and several variants including Eleg. AM (ARGDMP),
Eleg. PM (PRGDMP) and Eleg. PN (PRGDNP) were expressed as glutathione S
transferase (GST) fusion proteins in Escherichia coli. The inhibitory efficacies
of the panel of Elegantin variants were analysed in platelet adhesion assays with
substrates immobilized with fibrinogen and fibronectin. Elegantin molecules
containing an Ala residue N-terminal to the RGD sequence (wild-type Elegantin and
Eleg. AM) showed strong inhibitory activity towards alphaIIbbeta3-dependent
platelet adhesion on fibronectin, whereas a Pro residue in this position (Eleg.
PM and Kistrin, the inhibitor from the venom of Calloselasma rhodostoma)
engendered lower activity. The decreased activity could not be attributed to a
decrease in the affinity of the disintegrin for the alphaIIb beta3 complex
because both Eleg. AM and Eleg. PM had similar Kd (app) values. In contrast,
Elegantin molecules into which a Met residue was introduced in place of the Asn
residue C-terminal to the RGD sequence showed 10-13-fold elevated inhibitory
activity towards platelet adhesion on fibrinogen and this was maintained with
either a Pro or Ala residue N-terminal to the RGD sequence. In experiments with
the alpha5 beta1 complex on K562 cells, the inhibitory efficacies of the panel of
Elegantin molecules were analysed under two different cation conditions. First,
in the presence of Ca2+/Mg2+, K562 cell adhesion on fibronectin was inhibited
equally well by Elegantin and Eleg. AM but inhibited poorly by Eleg. PM and
Kistrin. In contrast with platelets, the decreased inhibitory efficacy of the
PRGDMP disintegrins was due to poor recognition of the alpha5 beta1 complex. In
the presence of Mn2+ cation, K562 cell adhesion on fibrinogen was observed in an
alpha5 beta1-dependent manner. Under these conditions both PRGD and ARGD
containing disintegrins were strong inhibitors of K562 cell adhesion on
fibrinogen and this was due to a markedly improved recognition of the alpha5
beta1 complex by the PRGD molecules. These observations demonstrate the pivotal
role of the amino acids flanking the RGD sequence for disintegrin recognition of
integrin complexes and highlight the subtle nature by which integrin-ligand
binding specificity can be modulated by both cation and adhesive motif.
PMID- 9761722
TI - The mouse ADP-ribosylation factor-like 4 gene: two separate promoters direct
specific transcription in tissues and testicular germ cell.
AB - ADP-ribosylation factor-like protein 4 (ARL4) is a Ras-related GTPase that has
been cloned from the 3T3-L1 preadipocyte cell line as an adipocyte-specific cDNA
[Schurmann, Breiner, Becker, Huppertz, Kainulainen, Kentrup and Joost (1994) J.
Biol. Chem. 269, 15683-15688]. The Arl4 gene maps to the proximal region of mouse
chromosome 12 linked to Lamb1-1, Hfhbf1 and Sos2. Compared with all other known
genes of Ras-related GTPases, the genomic organization of Arl4 is unusual in that
its entire coding region, the 3' untranslated region (UTR) and most of the 5' UTR
are located on a single exon. This structure suggests that Arl4 has evolved by
retroposition of an Arf (ADP-ribosylation factor) or Arf-like gene. Isolation of
the 5' UTR by rapid amplification of cDNA ends (RACE)-PCR revealed heterogeneous
transcription initiation sites in alternative exons 1. Both 5'-flanking regions
exhibited promoter activity when expressed in COS-7 cells, indicating that the
expression of Arl4 is directed by two separate promoters. mRNA transcribed under
the control of the downstream promoter was isolated by RACE-PCR from all
investigated tissues. In contrast, the upstream promoter seems to drive
specifically the expression of Arl4 in adult testis. Hybridization of rat testis
in situ indicated that Arl4 is expressed in germ cells of puberal and adult
testis, but not in prepuberal testis, suggesting that Arl4 is involved in sperm
production.
PMID- 9761723
TI - Cloning and characterization of GETS-1, a goldfish Ets family member that
functions as a transcriptional repressor in muscle.
AB - An Ets transcription factor family member, GETS-1, was cloned from a goldfish
retina cDNA library. GETS-1 contains a conserved Ets DNA-binding domain at its N
terminus and is most similar to ternary complex factor (TCF) serum-response
factor protein-1a (SAP-1a). GETS-1 is expressed in many tissues, but is enriched
in retina and brain. As with the TCFs SAP-1a and ets-related protein (ERP),
overexpression of the GETS-1 promoter suppresses nicotinic acetylcholine receptor
epsilon-subunit gene expression in cultured muscle cells. A consensus Ets binding
site sequence in the promoter of the epsilon-subunit gene is required for GETS-1
mediated repression. GETS-1 repressor activity is abrogated by overexpression of
an activated Ras/mitogen-activated protein kinase (MAP kinase) or by mutation of
Ser-405, a MAP kinase phosphorylation site in GETS-1. Fusion proteins created
between GETS-1 and the Gal4 DNA-binding domain show that, like other TCFs, GETS-1
contains a C-terminal activation domain that is activated by a Ras/MAP kinase
signalling cascade. Interestingly, mutation of Ser-405 located within this
activation domain abrogated transcriptional activation of the fusion protein.
PMID- 9761725
TI - The rate of sphingomyelin synthesis de novo is influenced by the level of
cholesterol in cultured human skin fibroblasts.
AB - Plasma membrane sphingomyelin (SM) is known to affect the cellular distribution
of cholesterol. The aim of this work was to examine how SM homoeostasis in human
skin fibroblasts is affected by alterations in the level of cholesterol in the
cell. The cellular cholesterol level was decreased by exposing cells to 2
hydroxypropyl-beta-cyclodextrin, and increased by exposing cells to cholesterol
methyl-beta-cyclodextrin inclusion complexes. A lowering of the cellular
unesterified cholesterol content by 20% was shown to increase the incorporation
of [14C]palmitic acid into SM by 70%. Subsequently, the cellular SM mass was
shown to be increased (24% increase after a 24 h period). Since l-cycloserine
completely abolished the increased incorporation of [14C]palmitic acid into SM in
cholesterol-depleted cells, we concluded that the de novo synthesis of the
sphingosine backbone of SM was activated in cholesterol-depleted cells. This
conclusion was further verified by performing a cell-free assay of serine C
palmitoyltransferase (SPT) in cholesterol-depleted cells, which showed that the
activity of the enzyme was increased by 30% after cholesterol depletion. Most of
the newly synthesized SM in cholesterol-depleted cells was susceptible to
degradation by sphingomyelinase, indicating that it was transported efficiently
to the cell surface. Loading of fibroblasts with cholesterol had essentially the
opposite effects on SM homoeostasis to those of cholesterol depletion, i.e. 20
30% decreased incorporation of [14C]palmitic acid into SM and decreased activity
of SPT. The results of this study show that cellular cholesterol levels have
marked effects on the homoeostasis of SM.
PMID- 9761724
TI - Functional analysis of the T-cell-restricted protein tyrosine kinase Txk.
AB - T lymphocytes express a range of tyrosine kinases that are involved in signalling
processes driving cell activation, proliferation and differentation. Two tyrosine
kinases expressed only in T cells, the Itk/Emt and Txk gene products, are members
of the Tec family of kinases. The role of Tec kinases in cellular function is
poorly understood, although a Tec kinase specific to B cells, Btk, is essential
for B-cell development. To explore the contribution of the T-cell-specific Tec
kinases to lymphocyte function, we have expressed human Txk in the baculovirus
system and conducted the first characterization of its activity. We find that Txk
exhibits a substrate preference in vitro quite distinct from that of the major T
cell kinases Lck and ZAP70, suggesting that Tec-family kinases might act on a
distinct range of substrates. We also investigated the interactions of Txk with
the cytoplasmic domains of the key signalling molecules CD3zeta, CD28 and CTLA4
and find that none of these are phosphorylated by Txk, nor are they ligands for
the SH2 or SH3 domains of Txk. We conclude that it is unlikely that Txk has a
role in the early signal transduction events associated with these key pathways
controlling T-cell activation.
PMID- 9761727
TI - Evidence for the presence of multiple forms of Sph kinase in human platelets.
AB - The intracellular distribution of sphingosine (Sph) kinase activity was examined
in human platelets. A large proportion (72%) of the total activity was found to
be associated with the membrane fraction, and the membrane-associated fraction
had higher specific activity compared with the cytosolic enzyme. Most of the
membrane-associated activity could be extracted with 1 M NaCl. The cytosolic
activity was unstable upon heat treatment, with 80% of the activity being lost
during incubation at 45 degreesC for 1 h, whereas the NaCl-extractable fraction
was stable under the same conditions. When subjected to Mono Q column
chromatography, the cytosolic fraction produced two activity peaks and the NaCl
extractable fraction gave a single peak. These three Sph kinase activities showed
different responses to stimulation by beta-octylglucoside and inhibition by N, N
dimethylsphingosine and l-threo-dihydrosphingosine, suggesting the presence of
multiple enzyme forms in human platelets.
PMID- 9761726
TI - Effect of nutritional state on the formation of a complex involving insulin
receptor IRS-1, the 52 kDa Src homology/collagen protein (Shc) isoform and
phosphatidylinositol 3'-kinase activity.
AB - The Src homology and collagen protein (Shc) is tyrosine phosphorylated in
response to insulin; however, evidence for its interaction with insulin receptor
(IR) in normal tissues is missing. Interactions between IR, Shc and regulatory
subunits of the phosphatidylinositol 3'-kinase (PI 3'-kinase) were characterized
in the present study in liver and muscles of chickens submitted to various
nutritional states. A chicken liver Shc cDNA fragment encoding a 198 amino acid
long fragment, including the phosphotyrosine binding domain was sequenced. It
shows 89% homology with the corresponding human homologue. The amounts of the
three Shc isoforms (66, 52 and 46 kDa) and Shc messenger were not altered by the
nutritional state. Shc tyrosine phosphorylation was decreased by fasting in both
liver and muscle. Importantly, Shc was immunoprecipitated by IR antibody (mostly
the 52 kDa isoform) or by alphaIRS-1(mostly the 46 kDa isoform). IR-Shc
association was decreased by fasting and restored by refeeding. In liver,
alphaShc immunoprecipitated the three forms of regulatory subunits of PI 3'
kinase and a PI 3'-kinase activity which was decreased by fasting. In muscle,
alphaShc immunoprecipitated only the p85 isoform; the associated PI 3'-kinase
activity was not altered by the nutritional state. Conversely, in both tissues
anti-p85 antibody precipitated only the 52 kDa Shc isoform. In liver, antibodies
to insulin receptor substrate-1 (alphaIRS-1), Shc or IR immunoprecipitated the
three regulatory subunits of PI 3'-kinase and an equal PI 3'-kinase activity,
without any residual activity left in the supernatants, suggesting the presence
of a large complex involving IR, IRS-1, Shc (mainly the 52 kDa isoform) and PI 3'
kinase activity. The presence of another complex containing IRS-1 and the 46 kDa
Shc isoform, but no PI 3'-kinase activity, is suggested.
PMID- 9761728
TI - Characterization of the hypertonically induced tyrosine phosphorylation of
erythrocyte band 3.
AB - Human erythrocyte band 3 becomes rapidly phosphorylated on tyrosine residues
after exposure of erythrocytes to hypertonic conditions. The driving force for
this phosphorylation reaction seems to be a decrease in cell volume, because (1)
changes in band 3 phosphotyrosine content accurately track repeated changes in
erythrocyte volume through several cycles of swelling and shrinking; (2) the
level of band 3 phosphorylation is independent of the osmolyte employed but
strongly sensitive to the magnitude of cell shrinkage; and (3) exposure of
erythrocytes to hypertonic buffers under conditions in which intracellular
osmolarity increases but volume does not change (nystatin-treated cells) does not
promote an increase in tyrosine phosphorylation. We hypothesize that shrinkage
induced tyrosine phosphorylation results either from an excluded-volume effect,
stemming from an increase in intracellular crowding, or from changes in membrane
curvature that accompany the decrease in cell volume. Although the net
phosphorylation state of band 3 is shown to be due to a delicate balance between
a constitutively active tyrosine phosphatase and constitutively active tyrosine
kinase, the increase in phosphorylation during cell shrinkage was demonstrated to
derive specifically from an activation of the latter. Further, a peculiar
inhibition pattern of the volume-sensitive erythrocyte tyrosine kinase that
matched that of p72syk, a tyrosine kinase already known to associate with band 3
in vivo, suggested the involvement of this kinase in the volume-dependent
response.
PMID- 9761729
TI - Energy requirements for two aspects of phospholipid metabolism in mammalian
brain.
AB - Previous estimates have placed the energy requirements of total phospholipid
metabolism in mammalian brain at 2% or less of total ATP consumption. This low
estimate was consistent with the very long half-lives (up to days) reported for
fatty acids esterified within phospholipids. However, using an approach featuring
analysis of brain acyl-CoA, which takes into account dilution of the precursor
acyl-CoA pool by recycling of fatty acids, we reported that half-lives of fatty
acids in phospholipids are some 100 times shorter (min-h) than previously
thought. Based on these new estimates of short half-lives, palmitic acid and
arachidonic acid were used as prototype fatty acids to calculate energy
consumption by fatty acid recycling at the sn-1 and sn-2 positions of brain
phospholipids. We calculated that the energy requirements for reacylation of
fatty acids into lysophospholipids are 5% of net brain ATP consumption. We also
calculated ATP requirements for maintaining asymmetry of the aminophospholipids,
phosphatidylserine and phosphatidylethanolamine across brain membrane bilayers.
This asymmetry is maintained by a translocase at a stoichiometry of 1 mol of ATP
per mol of phospholipid transferred in either direction across the membrane. The
energy cost of maintaining membrane bilayer asymmetry of aminophospholipids at
steady-state was calculated to be 8% of total ATP consumed. Taken together,
deacylation-reacylation and maintenance of membrane asymmetry of
phosphatidylserine and phosphatidylethanolamine require about 13% of ATP consumed
by brain as a whole. This is a lower limit for energy consumption by processes
involving phospholipids, as other processes, including phosphorylation of
polyphosphoinositides and de novo phospholipid biosynthesis, were not considered.
PMID- 9761730
TI - Evidence for a major structural change in Escherichia coli chorismate synthase
induced by flavin and substrate binding.
AB - Chorismate synthase (EC 4.6.1.4) catalyses the conversion of 5
enolpyruvylshikimate 3-phosphate (EPSP) into chorismate, and requires reduced FMN
as a cofactor. The enzyme can bind first oxidized FMN and then EPSP to form a
stable ternary complex which does not undergo turnover. This complex can be
considered to be a model of the ternary complex between enzyme, EPSP and reduced
FMN immediately before catalysis commences. It is shown that the binding of
oxidized FMN and EPSP to chorismate synthase affects the properties and structure
of the protein. Changes in small-angle X-ray scattering data, decreased
susceptibility to tryptic digestion and altered Fourier-transform (FT)-IR spectra
provide the first strong evidence for major structural changes in the protein.
The tetrameric enzyme undergoes correlated screw movements leading to a more
overall compact shape, with no change in oligomerization state. The changes in
the FT-IR spectrum appear to reflect changes in the environment of the secondary
structural elements rather than alterations in their distribution, because the
far-UV CD spectrum changes very little. Changes in the mobility of the protein
during non-denaturing PAGE indicate that the ternary complex may exhibit less
conformational flexibility than the apoprotein. Increased enzyme solubility and
decreased tryptophan fluorescence are discussed in the light of the observed
structural changes. The secondary structure of the enzyme was investigated using
far-UV CD spectroscopy, and the tertiary structure was predicted to be an alpha
beta-barrel using discrete state-space modelling.
PMID- 9761731
TI - Mammalian cell polyamine homeostasis is altered by the radioprotector WR1065.
AB - Mammalian cells become more susceptible to radiation-induced death and
mutagenesis when restricted in their production of the natural polyamines
putrescine, spermidine and spermine. The effects of polyamine deprivation are
reversed by N-(2-mercaptoethyl)-1, 3-diaminopropane (WR1065), a simple aminothiol
that has been extensively studied for its radioprotectant properties. Because
this compound and its oxidized derivative WR33278 bear some resemblance to the
polyamines, it was hypothesized that radioprotection by WR1065 or its metabolites
is derived, at least in part, from their ability to supplement the natural
polyamines. To evaluate the ability of these aminothiol compounds to emulate
polyamine function in intact cells, rat liver hepatoma (HTC) cells were treated
with radioprotective doses of WR1065; the ability of this compound to affect
various aspects of normal polyamine metabolism was monitored. Although cellular
WR1065 was maintained at levels exceeding those of the polyamines, this
aminothiol did not have any polyamine-like effect on the initial polyamine
biosynthetic enzyme, ornithine decarboxylase, or on polyamine degradative
reactions. On the contrary, treatment with relatively low levels of WR1065
resulted in an unexpected increase in putrescine and spermidine synthesis. WR1065
treatment enhanced the stability, and consequently the activity, of ornithine
decarboxylase. This stabilization seems to result from a WR1065-induced delay in
the synthesis of antizyme, a critical regulatory protein required in the feedback
modulation of polyamine synthesis and transport. The increase in cellular
spermidine induced by WR1065 might explain its antimutagenic properties, but is
probably not a factor in protection against cell killing by radiation. This is
the first evidence that compounds can be designed to control polyamine levels by
targeting the activity of the regulatory protein antizyme.
PMID- 9761732
TI - The effects of a Ca2+ chelator and heavy-metal-ion chelators upon Ca2+
oscillations and activation at fertilization in mouse eggs suggest a role for
repetitive Ca2+ increases.
AB - During fertilization in mouse eggs, the sperm triggers a series of intracellular
Ca2+ oscillations that lead to egg activation, as indicated by pronuclear
formation. We show that Ca2+ oscillations in fertilized mouse eggs can be
inhibited by addition of either the Ca2+ chelator 1,2-bis-(o-aminophenoxy)ethane
N,N,N',N'-tetra-acetic acid acetoxymethyl ester (BAPTA-AM) or the heavy-metal-ion
chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) plus
dithiothreitol (DTT). Both treatments inhibited Ca2+ oscillations, but they had
different effects upon egg activation. Blocking Ca2+ oscillations with BAPTA-AM
after the occurrence of just two Ca2+ spikes resulted in most eggs forming
pronuclei. However, we found that BAPTA-AM-treated fertilizing eggs showed a
decreased rate of protein synthesis, which by itself can promote egg activation.
In contrast, blocking Ca2+ oscillations with TPEN plus DTT was accompanied by the
inhibition of egg activation with no significant effect on protein synthesis. In
eggs that were fertilized and then treated with TPEN plus DTT, there was a
correlation between the number of Ca2+ spikes and the proportion of eggs that
formed pronuclei, as well as between the number of Ca2+ spikes and the time taken
for pronuclear formation and the first mitosis to occur. The addition of TPEN
plus DTT did not block the generation of Ca2+ spikes or pronuclear formation when
eggs were artificially stimulated by electroporation pulses. These data suggest
that TPEN plus DTT inhibits pronuclear formation in fertilizing eggs via the
inhibition of Ca2+ oscillations and that the number of Ca2+ spikes may regulate
egg activation.
PMID- 9761733
TI - Susceptibility towards intramolecular disulphide-bond formation affects
conformational stability and folding of human basic fibroblast growth factor.
AB - The conformational stability and the folding properties of the all-beta-type
protein human basic fibroblast growth factor (hFGF-2) were studied by means of
fluorescence spectroscopy. The results show that the instability of the
biological activity of hFGF-2 is also reflected in a low conformational stability
of the molecule. The reversibility of the unfolding and refolding process was
established under reducing conditions. Determination of the free-energy of
unfolding in the presence of reducing agents revealed that the conformational
stability of hFGF-2 (DeltaGH2Oapp congruent with21 kJ. mol-1, 25 degreesC) is low
compared with other globular proteins under physiological conditions (20-60
kJ.mol-1). However, the conformational stability of hFGF-2 is particularly low
under non-reducing conditions. This instability is attributed to intramolecular
disulphide-bond formation, rendering the molecule more susceptible to denaturant
induced unfolding. In addition, denaturant-induced unfolding of hFGF-2 renders
the protein more susceptible to irreversible oxidative denaturation. Experimental
evidence is provided that the irreversibility of the unfolding and refolding
process in the absence of reducing agents is linked to the formation of an
intramolecular disulphide bond involving cysteines 96 and 101.
PMID- 9761734
TI - Phosphatidylinositol 4-kinase, but not phosphatidylinositol 3-kinase, is present
in GLUT4-containing vesicles isolated from rat skeletal muscle.
AB - Insulin stimulates the rate of glucose transport into muscle and adipose cells by
translocation of glucose transporter (GLUT4)-containing vesicles from an
intracellular storage pool to the surface membrane. This event is mediated
through the insulin receptor substrates (IRSs), which in turn activate
phosphatidylinositol (PI) 3-kinase isoforms. It has been suggested that insulin
causes attachment of PI 3-kinases to the intracellular GLUT4-containing vesicles
in rat adipose cells. Furthermore, it has also been shown that GLUT4-containing
vesicles in adipose cells contain a PI 4-kinase. In the present study we
investigate whether GLUT4-containing vesicles isolated from rat skeletal muscle
display PI 3-kinase and/or PI 4-kinase activities. Insulin stimulation caused a
rapid increase (5-15-fold increase compared with control) in the intracellular
cytosolic IRS-1-associated PI-3 kinase activity. This PI 3-kinase activity was
also present in a membrane preparation containing the insulin-regulatable pool of
GLUT4 transporters. However, when GLUT4-containing vesicles were isolated by
immunoprecipitation from basal and insulin-stimulated (3 min) skeletal muscle,
the vesicles displayed PI 4-kinase, but not PI 3-kinase, activity. Insulin did
not regulate the PI 4-kinase activity in the GLUT4-containing vesicles. In
conclusion, GLUT4-containing vesicles from rat skeletal muscle contain a PI 4
kinase, but not a PI 3-kinase. It is suggested that, in skeletal muscle, insulin
causes activation of the IRS/PI 3-kinase complex in an intracellular membrane
compartment associated closely with the GLUT4-containing vesicles, but not in the
GLUT4-containing vesicles themselves.
PMID- 9761735
TI - Voltammetric studies of the reactions of iron-sulphur clusters ([3Fe-4S] or [M3Fe
4S]) formed in Pyrococcus furiosus ferredoxin.
AB - Reactions of the [3Fe-4S] cluster and various metallated [M3Fe-4S] adducts co
ordinated in the ferredoxin from the hyperthermophile Pyrococcus furiosus have
been studied by protein-film voltammetry, bulk-solution voltammetry, solution
kinetics and magnetic CD (MCD). The [3Fe-4S] cluster exhibits two couples, [3Fe
4S]+/0 and [3Fe-4S]0/2-. Film voltammetry is possible over a wide pH range (2-8),
revealing that the [3Fe-4S]+/0 couple shows a complex pH dependence with
pKred1=2.8, pKox=4.9 and pKred2=6.7. From MCD, pKred1 corresponds with
protonation of [3Fe-4S]0 to give a spectroscopically distinct species, as
reported for ferredoxins from Azotobacter and Sulfolobus. The status of the
disulphide/disulphydryl entity makes no significant difference to the data (given
for the -S-S- form). Formation of the hyper-reduced [3Fe-4S]2- state is observed,
requiring 3H+ for the overall 3e- reduction of [3Fe-4S]+, the change therefore
being electroneutral. By comparison with the ferredoxin from Desulfovibrio
africanus, uptake of Fe(II) and other M(II) by [3Fe-4S]0 to give [M3Fe-4S]
clusters is slow (t1/2>10 min at room temperature, slower still if the protein is
adsorbed on the electrode), whereas reaction with Tl(I) to produce [Tl3Fe-4S] is
very rapid (t1/2<<1 s), suggesting that co-ordination of Tl does not require
reorganization of the protein structure. Rates of formation of [3Fe-4S] from
[M3Fe-4S] adducts increase sharply at high potentials, showing that metal release
involves a labile 'super-oxidized' [M3Fe-4S]3+ state.
PMID- 9761736
TI - Sulphated glycosaminoglycans prevent the neurotoxicity of a human prion protein
fragment.
AB - Although a number of features distinguish the disease isoform of the prion
protein (PrPSc) from its normal cellular counterpart (PrPC) in the transmissible
spongiform encephalopathies (TSEs), the neuropathogenesis of these diseases
remains an enigma. The amyloid fibrils formed by fragments of human PrP have,
however, been shown to be directly neurotoxic in vitro. We show here that
sulphated polysaccharides (heparin, keratan and chondroitin) inhibit the
neurotoxicity of these amyloid fibrils and this appears to be mediated via
inhibition of the polymerization of the PrP peptide into fibrils. This provides a
rationale for the therapeutic effects of sulphated polysaccharides and suggests a
rapid in vitro functional screen for TSE therapeutics.
PMID- 9761737
TI - Secondary structure analysis of the putative membrane-associated domains of the
inward rectifier K+ channel ROMK1.
AB - The inward rectifier K+ channels contain two putative membrane-spanning domains
per subunit (M1, M2) and a 'pore' (P) region, which is similar to the H5 domain
of voltage-gated K+ channels. Here we have used Fourier transform infrared (FTIR)
and CD spectroscopy to analyse the secondary structures of synthetic peptides
corresponding to the M1, M2 and P regions of ROMK1 in aqueous solution, in
organic solvents and in phospholipid membranes. A previous CD study was unable to
provide any structural data on a similar P peptide [Ben-Efraim and Shai (1997)
Biophys. J. 72, 85-96]. However, our FTIR and CD spectroscopic analyses indicate
that this peptide adopts an alpha-helical structure when reconstituted into
dimyristoyl phosphatidylcholine vesicles and lysophosphatidyl choline (LPC)
micelles as well as in trifluoroethanol (TFE) solvent. This result is in good
agreement with a previous study on a peptide corresponding to the pore domain of
a voltage-gated K+ channel [Haris, Ramesh, Sansom, Kerr, Srai and Chapman (1994)
Protein Eng. 7, 255-262]. FTIR spectra of the M1 peptide in LPC micelles
displayed a strong absorbance characteristic of an intermolecular beta-sheet
structure, suggesting aggregation of the M1 peptide. Sucrose gradient
centrifugation was used to separate aggregated peptide from peptide incorporated
into micelles in an unaggregated manner; subsequent analysis by FTIR suggested
that the M1 peptide adopted an alpha-helical structure when incorporated into
phospholipid membranes. FTIR and CD spectra of the M2 peptide in phospholipids
and high concentrations of TFE suggest that this peptide adopts an alpha-helical
structure. The structural data obtained in these experiments have been used to
propose a model for the structure of the membrane-associated core (M1-P-M2) of
the inward rectifier K+ channel protein.
PMID- 9761738
TI - Human MUC5AC mucin dimerizes in the rough endoplasmic reticulum, similarly to the
MUC2 mucin.
AB - Biosynthetic studies on the human MUC5AC mucin were performed by
immunoprecipitations with antisera recognizing only the non-O-glycosylated
apomucin in the colon adenocarcinoma cell line LS 174T. Pulse-chase studies and
subcellular fractionations showed that MUC5AC formed dimers in the rough
endoplasmic reticulum within 15 min of the initiation of biosynthesis. No non-O
glycosylated species larger than dimers were identified. The dimerization was N
glycosylation-dependent, because tunicamycin treatment significantly lowered the
rate of dimerization. When the biosynthesis of MUC5AC apomucin was compared with
that of MUC2 apomucin, also produced in the LS 174T cell line, both apomucins
were assembled in similar ways with respect to their rates of dimerization with
and without inhibition of N-glycosylation. No heterodimerization was observed
between the human MUC5AC and the MUC2 apomucins despite the extensive sequence
similarities in the positions of the cysteine residues in the C-termini proposed
to be involved in mucin dimerization.
PMID- 9761739
TI - Cytosolic deglycosylation process of newly synthesized glycoproteins generates
oligomannosides possessing one GlcNAc residue at the reducing end.
AB - Recent studies on the mechanism of degradation of newly synthesized glycoproteins
suggest the involvement of a retrotranslocation of the glycoprotein from the
lumen of the rough endoplasmic reticulum into the cytosol, where a
deglycosylation process takes place. In the studies reported here, we used a
glycosylation mutant of Chinese hamster ovary cells that does not synthesize
mannosylphosphoryldolichol and has an increased level of soluble oligomannosides
originating from glycoprotein degradation. In the presence of anisomycin, an
inhibitor of protein synthesis, we observed an accumulation of glucosylated
oligosaccharide-lipid donors (Glc3Man5GlcNAc2-PP-Dol), which are the precursors
of the soluble neutral oligosaccharide material. Inhibition of rough endoplasmic
reticulum glucosidase(s) by castanospermine led to the formation of
Glc3Man5GlcNAc2(OSGn2) (in which OSGn2 is an oligomannoside possessing two GlcNAc
residues at its reducing end), which was then retained in the lumen of
intracellular vesicles. Thus they were protected during an 8 h chase period from
the action of cytosolic chitobiase, which is responsible for the conversion of
OSGn2 to oligomannosides possessing one GlcNAc residue at the reducing end
(OSGn1). In contrast, when protein synthesis was maintained in the presence of
castanospermine, glucosylated oligomannosides (Glc1-3Man5GlcNAc1) were recovered
in cytosol. Except for monoglucosylated Man5 species, which are potential
substrates for luminal calnexin and calreticulin, the pattern of oligomannosides
was similar to that observed on glycoproteins. The occurrence in the cytosol of
glucosylated species with one GlcNAc residue at the reducing end implies that the
deglycosylation process that generates glucosylated OSGn1 from glycoproteins
occurs in the cytosol.
PMID- 9761741
TI - Crystal structure of the family 7 endoglucanase I (Cel7B) from Humicola insolens
at 2.2 A resolution and identification of the catalytic nucleophile by trapping
of the covalent glycosyl-enzyme intermediate.
AB - Cellulose is the major polysaccharide component of the plant cell wall and the
most abundant naturally produced macromolecule on Earth. The enzymic degradation
of cellulose, by cellulases, is therefore of great environmental and commercial
significance. Cellulases are found in 12 of the glycoside hydrolase families
classified according to their amino acid sequence similarities. Endoglucanase I
(Cel7B), from the soft-rot fungus Humicola insolens, is a family 7 enzyme. The
structure of the native form of Cel7B from H. insolens at 2.2 A resolution has
been solved by molecular replacement using the known Trichoderma reesei
cellobiohydrolase I [Divne, Stahlberg, Reinikainen, Ruohonen, Pettersson,
Knowles, Teeri and Jones (1994) Science 265, 524-528] structure as the search
model. Cel7B catalyses hydrolysis of the beta-1,4 glycosidic linkages in
cellulose with net retention of anomeric configuration. The catalytic nucleophile
at the active site of Cel7B has been identified as Glu-197 by trapping of a 2
deoxy-2-fluorocellotriosyl enzyme intermediate and identification of the labelled
peptide in peptic digests by tandem MS. Site-directed mutagenesis of both Glu-197
and the prospective catalytic acid, Glu-202, results in inactive enzyme,
confirming the critical role of these groups for catalysis.
PMID- 9761740
TI - Phosphatidylinositol 3'-kinase associates with an insulin receptor substrate-1
serine kinase distinct from its intrinsic serine kinase.
AB - Serine phosphorylation of insulin receptor substrate-1 (IRS-1) has been proposed
as a counter-regulatory mechanism in insulin and cytokine signalling. Here we
report that IRS-1 is phosphorylated by a wortmannin insensitive
phosphatidylinositol 3'-kinase (PI 3-kinase)-associated serine kinase (PAS
kinase) distinct from PI 3-kinase serine kinase. We found that PI 3-kinase immune
complexes contain 5-fold more wortmannin-insensitive serine kinase activity than
SH2-containing protein tyrosine phosphatase-2 (SHP2) and IRS-1 immune complexes.
Affinity chromatography of cell lysates with a glutathione S-transferase fusion
protein for the p85 subunit of PI 3-kinase showed that PAS kinase associated with
the p85 subunit of PI 3-kinase. This interaction required unoccupied SH2
domain(s) but did not require the PI 3-kinase p110 subunit binding domain. In
terms of function, PAS kinase phosphorylated IRS-1 and, after insulin
stimulation, PAS kinase phosphorylated IRS-1 in PI 3-kinase-IRS-1 complexes.
Phosphopeptide mapping showed that insulin-dependent in vivo sites of IRS-1
serine phosphorylation were comparable to those of PAS kinase phosphorylated IRS
1. More importantly, PAS kinase-dependent phosphorylation of IRS-1 reduced by 4
fold the ability of IRS-1 to act as an insulin receptor substrate. Taken
together, these findings indicate that: (a) PAS kinase is distinct from the
intrinsic serine kinase activity of PI 3-kinase, (b) PAS kinase associates with
the p85 subunit of PI 3-kinase through SH2 domain interactions, and (c) PAS
kinase is an IRS-1 serine kinase that can reduce the ability of IRS-1 to serve as
an insulin receptor substrate.
PMID- 9761742
TI - Atypical protein kinase Clambda binds and regulates p70 S6 kinase.
AB - p70 S6 kinase (p70 S6K) has been implicated in the regulation of cell cycle
progression. However, the mechanism of its activation is not fully understood. In
the present work, evidence is provided that an atypical protein kinase C (PKC)
isotype, PKClambda, is indispensable, but not sufficient, for the activation of
p70 S6K. Both the regulatory and kinase domains of PKClambda associate directly
with p70 S6K. Overexpression of the kinase domain without kinase activity or the
regulatory domain of PKClambda results in the suppression of the serum-induced
activation of p70 S6K. In addition, two types of dominant-negative mutants of
PKClambda, as well as a kinase-deficient mutant of p70 S6K, suppress serum
induced DNA synthesis and E2F activation. The overexpresion of the active form of
PKClambda, however, fails to activate p70 S6K. These results suggest that
PKClambda is a mediator in the regulation of p70 S6K activity and plays an
important role in cell cycle progression.
PMID- 9761744
TI - Effects of cholesterol depletion by cyclodextrin on the sphingolipid microdomains
of the plasma membrane.
AB - Sphingolipid microdomains are thought to result from the organization of plasma
membrane sphingolipids and cholesterol into a liquid ordered phase, wherein the
glycosylphosphatidylinositol (GPI)-anchored proteins are enriched. These domains,
resistant to extraction by cold Triton X-100, can be isolated as buoyant membrane
complexes (detergent-resistant membranes) in isopycnic density gradients. Here
the effects of methyl-beta-cyclodextrin (MBCD), a specific cholesterol-binding
agent that neither binds nor inserts into the plasma membrane, were investigated
on the sphingolipid microdomains of lymphocytes. MBCD released substantial
quantities of GPI-anchored Thy-1 and glycosphingolipid GM1, and also other
surface proteins including CD45, and intracellular Lck and Fyn kinases. From
endothelial cells, MBCD released GPI-anchored CD59, and CD44, but only a
negligible amount of caveolin. Most MBCD-released Thy-1 and CD59 were not
sedimentable and thus differed from Thy-1 released by membrane-active cholesterol
binding agents such as saponin and streptolysin O, or Triton X-100. Unlike that
released by Triton X-100, only part of the Thy-1 molecules released by MBCD was
buoyant in density gradients and co-isolated with GM1. Finally, treatment of
Triton X-100-isolated detergent-resistant membranes with MBCD extracted most of
the cholesterol without affecting the buoyant properties of Thy-1 or GM1. We
suggest that (1) MBCD preferentially extracts cholesterol from outside, rather
than within the sphingolipid microdomains and (2) this partly solubilizes GPI
anchored and transmembrane proteins from the glycerophospholipid-rich membrane
and releases sphingolipid microdomains in both vesicular and non-vesicular form.
PMID- 9761743
TI - Involvement of a local fenton reaction in the reciprocal modulation by O2 of the
glucagon-dependent activation of the phosphoenolpyruvate carboxykinase gene and
the insulin-dependent activation of the glucokinase gene in rat hepatocytes.
AB - H2O2 mimicked the action of periportal pO2 in the modulation by O2 of the
glucagon-dependent activation of the phosphoenolpyruvate carboxykinase (PCK) gene
and the insulin-dependent activation of the glucokinase (GK) gene. H2O2 can be
converted in the presence of Fe2+ in a Fenton reaction into hydroxyl anions and
hydroxyl radicals (.OH). The hydroxyl radicals are highly reactive and might
interfere locally with transcription factors. It was the aim of the present study
to investigate the role of and to localize such a Fenton reaction. Hepatocytes
cultured for 24 h were treated under conditions mimicking periportal or
perivenous pO2 with glucagon or insulin plus the iron chelator desferrioxamine
(DSF) or the hydroxyl radical scavenger dimethylthiourea (DMTU) to inhibit the
Fenton reaction. PCK mRNA was induced by glucagon maximally under conditions of
periportal pO2 and half-maximally under venous pO2. GK mRNA was induced by
insulin with reciprocal modulation by O2. DSF and DMTU reduced the induction of
PCK mRNA to about half-maximal and increased the induction of GK mRNA to maximal
under both O2 tensions. Hydroxyl radical formation was maximal under arterial
pO2. Perivenous pO2, DSF and DMTU each decreased the formation of .OH to about
70% of control. The Fenton reaction could be localized in a perinuclear space by
confocal laser microscopy and three-dimensional reconstruction techniques. In the
same compartment, iron could be detected by electron-probe X-ray microanalysis.
Thus a local Fenton reaction is involved in the O2 signalling, which modulated
the glucagon- and insulin-dependent PCK gene and GK gene activation.
PMID- 9761745
TI - Purification and biochemical characterization of a poly(ADP-ribose) polymerase
like enzyme from the thermophilic archaeon Sulfolobus solfataricus.
AB - A poly(ADP-ribose) polymerase-like enzyme, detected in a crude homogenate from
Sulfolobus solfataricus by means of activity and immunoblot analyses, was
purified to electrophoretic homogeneity by a rapid procedure including two
sequential affinity chromatographies, on NAD+-agarose and DNA-Sepharose. The
latter column selected specifically the poly(ADP-ribosyl)ating enzyme with a 17%
recovery of enzymic activity and a purification of more than 15000-fold. The
molecular mass (54-55 kDa) assessed by SDS/PAGE and immunoblot was definitely
lower than that determined for the corresponding eukaryotic protein. The enzyme
was proved to be thermophilic, with a temperature optimum of approx. 80 degreesC,
and thermostable, with a half-life of 204 min at 80 degreesC, in good agreement
with the requirements of a thermozyme. It displayed a Km towards NAD+ of 154+/-50
microM; in the pH range 6.5-10.0 the activity values were similar, not showing a
real optimum pH. The enzyme was able to bind homologous DNA, as evidenced by the
ethidium bromide displacement assay. The product of the ADP-ribosylating reaction
co-migrated with the short oligomers of ADP-ribose (less than 6 residues) from a
eukaryotic source. Reverse-phase HPLC analysis of the products, after digestion
with phosphodiesterase I, gave an elution profile reproducing that obtained by
the enzymic digestion of the rat testis poly(ADP-ribose). These results strongly
suggest that the activities of the purified enzyme include the elongation step.
PMID- 9761746
TI - Identification of glu-277 as the catalytic nucleophile of Thermoanaerobacterium
saccharolyticum beta-xylosidase using electrospray MS.
AB - Thermoanaerobacterium saccharolyticum beta-xylosidase is a member of family 39 of
the glycosyl hydrolases. This grouping comprises both retaining beta-d
xylosidases and alpha-l-iduronidases. T. saccharolyticum beta-xylosidase
catalyses the hydrolysis of short xylo-oligosaccharides into free xylose via a
covalent xylosyl-enzyme intermediate. Incubation of T. saccharolyticum beta
xylosidase with 2,4-dinitrophenyl 2-deoxy-2-fluoro-beta-d-xyloside resulted in
time-dependent inactivation of the enzyme (inactivation rate constant ki=0.089
min-1, dissociation constant for the inactivator Ki=65 microM) through the
accumulation of a covalent 2-deoxy-2-fluoro-alpha-d-xylosyl-enzyme, as observed
by electrospray MS. Removal of excess inactivator and regeneration of the free
enzyme through transglycosylation with either xylobiose or thiobenzyl xyloside
demonstrated that the covalent intermediate was kinetically competent. Peptic
digestion of the 2-deoxy-2-fluoro-alpha-d-xylosyl-enzyme intermediate and
subsequent analysis by electrospray ionization triple-quadrupole MS in the
neutral-loss mode indicated the presence of a 2-deoxy-2-fluoro-alpha-d-xylosyl
peptide. Sequence determination of the labelled peptide by tandem MS in the
daughter-ion scan mode permitted the identification of Glu-277 (bold and
underlined) as the catalytic nucleophile within the sequence IILNSHFPNLPFHITEY.
PMID- 9761747
TI - Sialomucin complex at the rat ocular surface: a new model for ocular surface
protection.
AB - The ocular surface, which is among the most accessible and vulnerable tissues in
mammals, is protected by a complex tear film composed of lipid, aqueous and mucin
layers. In spite of its importance, the molecular nature of the mucin
contribution remains uncertain. Since membrane mucins have been implicated in the
protection of other epithelia, we have analysed rat corneal and conjunctival
tissues for sialomucin complex (SMC), a membrane mucin found at the apical
epithelial cell surfaces in the airway and uterus. Using Northern and Western
blot analyses, SMC expression was found in both ocular tissues, being
particularly abundant in the cornea. In contrast with the other known membrane
mucin, MUC1, SMC was localized more heavily towards the apical surface of the
epithelial cells. SMC in ocular surface epithelia was produced in both soluble
and membrane forms, the latter being found predominantly in the most superficial
cells and at apical surfaces. The soluble form was found loosely adsorbed to
apical cell surfaces, particularly of the cornea, as indicated by a mild rinsing
protocol. Finally, the tear fluid contained substantial amounts of SMC. From
these results, we propose a new model for tear mucin components in which SMC is
expressed at the apical ocular surface in both membrane-bound and adsorbed
soluble forms to provide a direct protective barrier. SMC secreted into the tear
fluid may also participate in maintaining the stability of the preocular tear
film by acting with other secreted mucins to determine the physical properties
and protective behaviour of the tear film.
PMID- 9761748
TI - The function of cell adhesion molecules in lung inflammation: more questions than
answers.
PMID- 9761749
TI - Expression of Fas (CD95) and FasL (CD95L) in human airway epithelium.
AB - The cell surface molecule Fas (CD95) is a member of the tumor necrosis factor
receptor family. Ligation of the Fas receptor can lead to induction of apoptosis
in inflammatory cells. It has been suggested that expression of the Fas receptor
and its ligand (FasL) in airway epithelium may modulate the inflammatory response
commonly found in asthmatic lungs. We examined Fas and FasL expression on primary
human tissues, on bronchial epithelial cells in primary culture, and on the
immortalized human airway epithelial cell line, 1HAEo-. Receptor and ligand
expression were demonstrated using multiple antibodies and multiple techniques,
including immunohistochemistry, flow cytometry, Western blots, and reverse
transcription-polymerase chain reaction (RT-PCR). Immunohistochemical staining
demonstrated that both columnar and basal cells of intact human lung tissues
expressed cell surface Fas and FasL. In addition, both primary cultured and
immortalized 1HAEo- cells expressed cell surface Fas and FasL, as demonstrated by
flow cytometry; expression of Fas and FasL was confirmed at the transcription
level using RT-PCR and, for additional confirmation of FasL, using Western blots.
We demonstrate that both Fas and FasL are expressed by human airway epithelial
cell subtypes. Expression of these molecules may play an important role in
regulation of the inflammatory response.
PMID- 9761750
TI - Increased endothelial cell expression of platelet-endothelial cell adhesion
molecule-1 during hyperoxic lung injury.
AB - Lung injury is a frequent consequence of oxygen (O2) therapy administered to
newborns and adults with respiratory distress. Acute exposure to hyperoxia
results in a well-described pathophysiologic response in the lungs. Because
inflammation is an important component of pulmonary O2 toxicity, we have an
interest in identifying the inflammatory mediators that increase during
hyperoxia. Platelet-endothelial cell adhesion molecule-1 (PECAM-1), a member of
the immunoglobulin superfamily that is expressed at the junctions between
endothelial cells, is essential to the transendothelial migration of leukocytes.
We hypothesized that increased expression of PECAM-1 occurs in pulmonary
endothelial cells during hyperoxic lung injury. Adult mice were exposed to 100%
O2 for up to 96 h. We analyzed PECAM-1 expression by RNA blot hybridization, in
situ hybridization, and immunohistochemistry. A increase in PECAM-1 mRNA was seen
as soon as 2 d of hyperoxia relative to unexposed control mice. PECAM-1 mRNA and
protein were found in endothelial cells of both large and small arteries. The
expression of PECAM-1 in capillary vessels was further confirmed using in situ
hybridization at the electron microscope level. This increase in PECAM-1
expression coincided with the appearance of leukocytes in lung tissue. These
observations suggest that PECAM-1 expression is a relatively early step in the
inflammation cascade, and intervention at this phase may be critical to the
prevention of further damage.
PMID- 9761751
TI - Expression of heterogeneous nuclear ribonucleoprotein A2/B1 changes with critical
stages of mammalian lung development.
AB - Recent reports have demostrated a link between expression of members of the
family of heterogeneous nuclear ribonucleoproteins (hnRNPs) and cancer.
Overexpression of hnRNP A2/B1 correlated with the eventual development of lung
cancer in three different clinical cohorts. We have studied the expression of
hnRNP A2/B1 messenger RNA (mRNA) and protein during mammalian development. The
expression of hnRNP A2/B1 mRNA and protein are parallel but change dynamically
during critical periods in mouse pulmonary development. hnRNP A2/B1 is first
detected in the lung in the early pseudoglandular period, peaks at the beginning
of the canalicular period, and remains high during the saccular (alveolar)
period. In mouse and rat, hnRNP A2/B1 expression is first evident in the earliest
lung buds. As lung development progresses, the cuboidal epithelial cells of the
distal primitive alveoli show high levels of the ribonucleoprotein, which is
almost undetectable in the proximal conducting airways. The expression of hnRNP
A2/ B1 is restricted in mature lung. Similar dynamic pattern of expression
through lung development was also found in rat and human lung. Upregulated
expression of hnRNP A2/B1 at critical periods of lung development was comparable
to the level of expression found in lung cancers and preneoplastic lesions and is
consistent with hnRNP A2/B1 overexpression playing an oncodevelopmental role.
PMID- 9761752
TI - Differential expression of fibroblast growth factor receptors 1 to 4 and ligand
genes in late fetal and early postnatal rat lung.
AB - To characterize fibroblast growth factor (FGF) gene expression in the late fetal
(days E18 to E22) and early postnatal lung (days P0 to P28), when the alveolar
region undergoes extensive growth and reorganization, we analyzed the expression
of four FGF receptors and six ligands. FGF receptor 1 (FGFR1) RNA levels were
first low (E18) before rising late in the postnatal period (P28). FGFR2 RNA
levels were detected early (at E18) and then increased (E20-P0) before falling
(P2) to below later postnatal levels (P6 to P28). FGFR3 RNA levels were low at
first (E18) and then increased, with peak levels in the days after birth (P2 to
P10). FGFR4 RNA levels, barely detected in fetal lung (E18 to E22), increased at
birth (P0) and remained high postnatally (P2 to P28). In fetal lung, FGF2 (basic
FGF) RNA expression levels were low and FGF1 (acidic FGF) RNA levels were not
detected: low RNA levels of each ligand were detected postnatally (P7 to P28).
FGF3 to 5 and FGF7 RNA were not detected in fetal or postnatal lung. With in situ
hybridization, predominantly the smooth muscle cells of large vessels expressed
FGFR1 and 4 mRNA; the epithelial cells of large airways expressed FGFR1, 2, and
4; and alveolar cells expressed FGFR2, 3, and 4. Analysis of protein expression
first identified FGF2 localized to the basement membrane of large airways and
branching epithelial buds, to mesenchymal cells associated with buds, to the
putative smooth muscle cells of large airways and vessels, and to pleural- and
mesenchymal-associated cells (E18). Immediately before birth, this pattern of
expression persisted (E20 to E22), with FGF2 also being expressed by putative
smooth muscle cells of smaller airways and vessels (E22). After birth (P0 to
P28), FGF2 expression remained relatively high in the smooth muscle cells of
large and small vessels and in pleural cells; in airway smooth muscle cells and
in most cells in the alveolar region, however, although FGF2 expression persisted
in some cells, its intensity decreased with time.
PMID- 9761754
TI - Expression of lumican in human lungs.
AB - The collagen-elastin-proteoglycan (PG) matrix is the key constituent of lung
parenchyma and plays a major role in the mechanical behavior of lung tissues.
However, the exact composition of the PG matrix in lungs has not yet been fully
determined. In the present study we report the expression of leucine-rich repeat
PGs in adult human lungs. PG extraction was performed on peripheral lung tissue
from patients undergoing therapeutic lung resections. The samples were analyzed
by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting
using antipeptide antisera specific to human lumican, decorin, biglycan, and
fibromodulin. Control experiments to verify antiserum reactivity were performed
with an extract of adult human articular cartilage, which is known to contain all
four PGs. In all lung extracts analyzed, a single component of molecular weight
65 to 90 kD was detected for lumican. Decorin, biglycan, and fibromodulin were
either not detected or were barely detectable in the lung extracts, but were
readily visualized in the cartilage samples. Immunohistochemistry showed that
lumican was diffusely present in peripheral lung tissue, mainly in vessel walls.
These results suggest that lumican is a major component of the PG matrix in adult
human lungs.
PMID- 9761753
TI - Oxygen toxicity in mouse lung: pathways to cell death.
AB - Mice exposed to 100% O2 die after 3 or 4 d with diffuse alveolar damage and
alveolar edema. Extensive cell death is evident by electron microscopy in the
alveolar septa, affecting both endothelial and epithelial cells. The damaged
cells show features of both apoptosis (condensation and margination of chromatin)
and necrosis (disruption of the plasma membrane). The electrophoretic pattern of
lung DNA indicates both internucleosomal fragmentation, characteristic of
apoptosis, and overall degradation, characteristic of necrosis. Hyperoxia induces
a marked increase in RNA or protein levels of p53, bax, bcl-x, and Fas, which are
known to be expressed in certain types of apoptosis. However, we did not detect
an increased activity of proteases belonging to the apoptosis "executioner"
machinery, such as CPP32 (caspase 3), ICE (caspase 1), or cathepsin D.
Furthermore, administration of an ICE-like protease inhibitor did not
significantly enhance the resistance to oxygen. Additionally, neither p53
deficient mice nor lpr mice (Fas null) manifested an increased resistance to
hyperoxia-induced lung damage. These results show that both necrosis and
apoptosis contribute to cell death during hyperoxia. Multiple apoptotic pathways
seem to be involved in this, and an antiapoptotic strategy does not attenuate
alveolar damage.
PMID- 9761755
TI - T and B cell independence of endothelial cell adhesion molecule expression in
pulmonary granulomatous inflammation.
AB - A pulmonary Cryptococcus neoformans (Cne: strain 52D, ATCC24067) infection model
in mice was used to examine the possible role for T cell-mediated immunity in
regulating vascular adhesion molecules on lung endothelium during development of
granulomatous inflammation. Resolution of pulmonary Cne infection in C.B-17 mice
begins by Day 14 following intratracheal inoculation and depends on T cell
mediated recruitment of monocytes followed by their activation. C.B-17 scid/scid
(SCID) mice mount a less exuberant pulmonary inflammatory response, recruit fewer
monocytes into their lungs, and fail to clear the infection. Recruitment of
leukocytes into infected tissue is mediated by both the interaction of adhesion
molecules expressed on the surface of activated vascular endothelial cells with
ligands on circulating cells, and the directed response of these leukocytes to
chemotactic factors. The kinetics of expression of the endothelial cell adhesion
molecules E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and
intercellular adhesion molecule-1 (ICAM-1), all previously shown to regulate
monocyte recruitment, were examined in the lungs of infected C.B-17 and SCID mice
during pulmonary infection to determine if T cells were necessary for their
upregulation. Immunohistochemical analysis showed that upregulation of E
selectin, VCAM-1, and ICAM-1 did not differ significantly between C.B-17 and SCID
mice at any time during infection. Maximal expression in C.B-17 and SCID mice was
noted between Days 5 and 7 for all three molecules and preceded maximal influx of
leukocytes into the lung. Thus, the inability of SCID mice to recruit optimal
numbers of monocytes into infected lungs was not the result of a failure to
express the critical adhesion molecules early in infection, but likely reflected
absence of immune dependent chemotactic factors.
PMID- 9761756
TI - Glucocorticoid-induced apoptosis of dendritic cells in the rat tracheal mucosa.
AB - Dendritic cells are antigen-presenting cells that constitutively express high
levels of major histocompatibility complex class II (Ia) antigen on their plasma
membrane. Previous studies have shown that the number of dendritic cells in the
rat airway mucosa decreases rapidly after glucocorticoid treatment. We sought to
determine whether apoptosis contributes to this steroid-induced cell decrease.
Dendritic cells in tracheal whole mounts were revealed by immunoperoxidase
staining using the OX-6 (anti-Ia) monoclonal antibody. In untreated rats, a dense
network of Ia-immunoreactive (Ia+) cells with highly branched cytoplasmic
processes was observed just beneath the tracheal epithelium (1,405 +/- 140
cells/mm2 mucosa; mean +/- SEM, n = 6). In rats treated with dexamethasone (10
mg/kg, intraperitoneally), four distinct changes in dendritic cell morphology
were evident 4 to 8 h after injection: (1) appearance of large Ia+ granules in
cytoplasmic processes, (2) narrowing of cytoplasmic processes, (3) loss of Ia
immunoreactivity from the cell surface, and (4) fragmentation of cells into small
Ia+ bodies. These changes accompanied a 56% decrease in the number of Ia+ cells
over 8 h. The contribution of apoptosis to this decrease in Ia+ cells was
determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end
labeling (TUNEL) of nucleosomal DNA fragments in histologic sections. The number
of TUNEL+ bodies increased from a control value of 174 +/- 47 bodies/mm2 mucosa
to 2,108 +/- 294 bodies/mm2 mucosa at 4 h and 936 +/- 343 bodies/ mm2 mucosa at 8
h (n = 4 rats per time point). The location of TUNEL+ bodies closely corresponded
to that of Ia+ cells stained in adjacent histologic sections. We conclude that
apoptosis contributes to the rapid decrease in airway dendritic cells after
glucocorticoid treatment.
PMID- 9761758
TI - SP-A2 gene expression in human fetal lung airways.
AB - In the present study, we characterized surfactant protein (SP)-A messenger RNA
(mRNA) in mid-trimester human fetal trachea and bronchi. SP-A protein was
localized by immunocytochemistry to scattered epithelial cells in the airway
surface epithelium and in submucosal glands of the fetal trachea and bronchi. SP
A mRNA (2.2 kb) was detected by Northern blot analysis in human fetal trachea, as
well as in primary and more distal bronchi. The levels of detectable SP-A mRNA
were highest in the upper airways and were decreased in smaller bronchi in
comparison. SP-A mRNA was barely detectable in the distal fetal lung tissue. In
contrast, SP-A mRNA was abundant in cultured explants of distal human fetal lung
tissue. SP-A1 and SP-A2 mRNA were detected by primer extension analysis in adult
human lung tissue and in cultured human fetal lung explants. Only SP-A2 mRNA was
detected in RNA isolated from human fetal trachea and bronchi. SP-A mRNA was
localized by in situ hybridization in the fetal trachea and bronchi in scattered
cells in the surface epithelium and, most prominently, in submucosal glands. Our
results suggest that SP-A2, and not SP-A1, is produced in the human fetal
tracheal and bronchial epithelium and in submucosal glands.
PMID- 9761757
TI - Proliferation of human non-small-cell lung cancer cell lines: role of interleukin
6.
AB - Interleukin-6 (IL-6) is involved in regulation of the immune response, acute
phase reaction, and cell proliferation. The aim of this study was to investigate
whether IL-6 is implicated in cell proliferation of human non-small-cell lung
cancer (NSCLC) cell lines. We analyzed IL-6 messenger RNA (mRNA) and protein
expression in eight NSCLC cell lines: A549, Calu3, Calu6, H23, H522, H810, H1155,
and H1299. The A549, Calu3, Calu6, and H23 cell lines expressed IL-6 mRNA and
protein. In these cell lines, fetal calf serum (FCS) significantly increased cell
proliferation as assessed by thymidine incorporation. In the presence of IL-6
antisense oligonucleotides, both proliferation and IL-6 synthesis were
downregulated. In contrast, IL-6 mRNA and protein could not be detected in the
NSCLC cell lines H522, H810, H1155, and H1299. In these NSCLC cell lines, FCS
only marginally increased cell proliferation and IL-6 antisense oligonucleotides
did not affect cell proliferation. The addition of neither exogenous IL-6 nor
neutralizing anti-IL-6 antibodies affected cell proliferation in any of the
experiments. Our data thus provide evidence that intracellular IL-6 is required
in the control of cell proliferation in a subset of human NSCLC cell lines. We
suggest the existence of two subtypes of NSCLC, an IL-6-dependent and an IL-6
independent type.
PMID- 9761759
TI - Allergen immunotherapy inhibits airway eosinophilia and hyperresponsiveness
associated with decreased IL-4 production by lymphocytes in a murine model of
allergic asthma.
AB - In the present study, we investigated whether allergen immunotherapy is effective
in a murine model with immunologic and pathophysiologic features reminiscent of
allergic asthma. Ovalbumin-sensitized mice received increasing (1 microgram to 1
mg) subcutaneous doses of ovalbumin twice a week for 8 wk according to a semirush
immunotherapy protocol as used in allergic patients. During immunotherapy, an
initial rise in serum levels of ovalbumin-specific antibodies (immunoglobulin
[Ig]G1, IgE, IgG2a) occurred, after which IgE levels decreased sharply
concomitant with an increase in IgG2a levels. The increase in IgG2a levels, with
the decline in IgE levels, suggests that during immunotherapy interferon-gamma
production is increased or interleukin (IL)-4 production is decreased. After
immunotherapy, inhalation challenge of the mice with ovalbumin revealed almost
complete inhibition (98%, P < 0.01) of eosinophil infiltration into
bronchoalveolar lavage and airway hyperresponsiveness (100% at 320 microgram/kg
methacholine, P < 0.05) compared with sham-treated animals. In addition, IL-4
production of thoracic lymph node cells stimulated with ovalbumin in vitro was
largely reduced (60%, P < 0.05) after immunotherapy. Thus, effective
immunotherapy in this animal model appears to be due to modulation of antigen
specific T cells. Similar effects on airway symptoms and IL-4 production can be
obtained within 1 wk by three injections of the highest dose of ovalbumin (1 mg).
This animal model will be used as a preclinical model to improve allergen
immunotherapy and to gain more insight into the mechanisms involved.
PMID- 9761760
TI - Tumor necrosis factor-alpha stimulates human Clara cell secretory protein
production by human airway epithelial cells.
AB - Clara cell secretory protein (CCSP), or CC10, is an inhibitor of secretory
phospholipase A2 which may be produced by phagocytic cells and by a variety of
other cells in the airway. Tumor necrosis factor-alpha (TNF-alpha) is capable of
activating phospholipases and inducing the expression of a variety of genes in
the airway epithelium which may modulate the airway inflammatory response.
Therefore, it was of interest to determine whether this proinflammatory cytokine
could induce the production of a counterregulatory protein such as CCSP which
might modulate the production of eicosanoid mediators in the airway. Using a
human bronchial epithelial cell line (BEAS-2B), CCSP messenger RNA (mRNA) levels
were detected by ribonuclease protection assay. TNF treatment of these cells
increased CCSP mRNA levels in a time- and dose-dependent manner. The CCSP mRNA
level increased in response to TNF-alpha (20 ng/ml) stimulation after 8 to 36 h
with the peak increase at 18 h. Immunoblotting of CCSP protein released into the
culture media demonstrated that TNF-alpha induced the synthesis and secretion of
CCSP protein in a time-dependent manner over 8 to 18 h. The results of a CCSP
reporter gene activity assay, nuclear run-on assay, and CCSP mRNA half-life assay
indicated that the TNF-alpha-induced increases in CCSP gene expression are
regulated at the post-transcriptional level. We conclude that TNF-alpha induces
airway epithelial cell expression of human CCSP protein and may modulate airway
inflammatory responses in this manner.
PMID- 9761761
TI - Expression of the human integrin beta6 subunit in alveolar type II cells and
bronchiolar epithelial cells reverses lung inflammation in beta6 knockout mice.
AB - Inactivation of the integrin beta6 subunit gene in mice resulted in an unexpected
phenotype-functionally significant inflammation of the skin and lungs. These
findings suggested a role for ligation of the alphav beta6 integrin on epithelial
cells in downregulating epithelial inflammation. However, the results of gene
inactivation could have been due to inactivation of adjacent genes and provided
no information about the role of this integrin in specific populations of
epithelial cells. In the current study, we used transgenic mice constitutively
expressing the human beta6 subunit in alveolar type II cells and bronchiolar
epithelial cells to examine directly the significance of alphav beta6 in these
cells. Expression of this transgene largely inhibited the increases in airspace
lymphocytes and macrophages and the lymphocyte and macrophage activation caused
by inactivation of the beta6 subunit gene, and reduced the peribronchial and
perivascular accumulations of lymphocytes. In the genetically mixed mice used for
this study, we identified airway eosinophilia as an additional effect of beta6
inactivation. This effect was also partially inhibited by limited expression of
the human transgene. These results definitively identify a role for distal lung
epithelial alphav beta6 in downregulating pulmonary inflammation and suggest that
interventions augmenting beta6 expression or function in these cells could
influence the course of inflammatory lung diseases.
PMID- 9761762
TI - The effect of chloride concentration on human neutrophil functions: potential
relevance to cystic fibrosis.
AB - Recently, some investigators have observed elevated concentrations of chloride in
the airway surface fluid (ASF) overlying respiratory epithelia from cystic
fibrosis (CF) patients compared with ASF overlying non-CF epithelia. Others have
shown that this elevated ASF salt concentration can inactivate human beta
defensin-1, an antimicrobial peptide secreted by respiratory epithelia. This
could impair the primary epithelial defense against bacteria in the CF airway,
thereby forcing a greater reliance on polymorphonuclear leukocyte (PMN)-mediated
defenses. Pseudomonas aeruginosa (Psa) flourishes in the CF airway despite the
presence of abundant PMN. We therefore investigated whether elevated ASF chloride
concentration in CF might also compromise PMN function. We employed a cell
culture model in which halide concentrations and osmolarity were varied
independently. We examined the effects of chloride concentration on three aspects
of PMN function: recruitment of PMN to the airway (production of interleukin-8
[IL-8]), PMN antimicrobial activity (killing of Psa), and PMN clearance from the
airways (apoptosis and lysis). We found that exposure to elevated chloride
concentration increased PMN synthesis of IL-8, decreased PMN killing of Psa, and
accelerated PMN apoptosis and lysis. In CF airways, elevated chloride therefore
could contribute to the increased number of PMN recruited into the airways, the
increased survival of Psa, and the increased quantity of toxic mediators released
by PMN into the airways. These effects of elevated chloride on PMN function may
provide another causal link between loss of cystic fibrosis transmembrane
conductance regulator function and CF lung disease.
PMID- 9761763
TI - Hypoxia-induced interleukin-6 and interleukin-8 production is mediated by
platelet-activating factor and platelet-derived growth factor in primary human
lung cells.
AB - Hypoxia has been shown to induce the expression of different growth factors,
cytokines, and proinflammatory mediators, including platelet-derived growth
factor (PDGF), interleukin-6 (IL-6), interleukin-8 (IL-8), and platelet
activating factor (PAF) in animal models. PAF and PDGF are thought to play
important roles in vascular remodeling and have been shown to induce expression
of IL-6 and IL-8 genes under normoxic conditions. We hypothesize that de novo
synthesis of IL-6, IL-8, and cell proliferation is enhanced in human pulmonary
cells under hypoxic cell culture conditions. We further assumed an important role
of PAF and/or PDGF in hypoxia-induced cell activation. Using cultures of primary
human pulmonary fibroblasts and pulmonary vascular smooth muscle cells (VSMC) we
show that hypoxia (3% O2) induced transcription and translation of IL-6 (4- to 5
fold) and IL-8 (5- to 6-fold) in both cell types. Hypoxia-induced expression of
IL-6 was suppressed by 50% to 60% in the presence of the PAF antagonist WEB2170,
or neutralizing anti-PDGF antibodies. In addition, we demonstrate that hypoxia
induces a threefold increase of cell proliferation of fibroblasts and a twofold
increase of VSMC proliferation. Similar to the effect on IL-6 and IL-8 synthesis,
WEB2170 or neutralizing anti-PDGF antibodies downregulated hypoxia-induced
proliferation of fibroblasts and VSMC by 50%. Our data show that PAF and PDGF are
important mediators for hypoxia-induced cell activation and cytokine release in
the human lung. We therefore hypothesize that IL-6 and IL-8 contribute to the
progression of lung diseases associated with hypoxia, and that both
proinflammatory factors, PAF and PDGF, are involved in hypoxia-dependent
expression of IL-6 and IL-8 in human pulmonary fibroblasts and VSMC.
PMID- 9761764
TI - Characterization of the gene and promoter for RTI40, a differentiation marker of
type I alveolar epithelial cells.
AB - In an effort to understand the processes that establish and maintain the
differentiated state of the alveolar epithelium, we have analyzed the gene for
rat type I cell 40 kD protein (RTI40), an apical integral plasma membrane protein
expressed in type I but not type II alveolar epithelial cells. The RTI40 gene
spans 35 kilobase pairs; it contains 6 exons and at least 6 rat Identifier
repetitive elements. Three exons encode the predicted RTI40 extracellular domain
and one encodes the single transmembrane spanning domain. The final exon encodes
one amino acid followed by a stop codon. RTI40 gene transcription starts
downstream from a TATA homology, which is immediately adjacent to putative
binding sites for thyroid transcription factor 1 and Sp1. In H441 cell
transfections, mutagenesis of a 5'-flanking fragment (-2496 to +104) revealed two
regions that contribute to promoter activity: -1247 through -795 and -163 through
-81. Heterologous promoter fusion experiments suggest that a cooperative
interaction between these regions activates transcription. In transfected type II
cells, deletion across the proximal region produced a 6-fold drop in promoter
activity, whereas deletion across the distal region was without apparent effect.
These results provide a foundation to analyze further the factors that govern
alveolar epithelial cell phenotype.
PMID- 9761765
TI - Induction of the lung myofibroblast PDGF receptor system by urban ambient
particles from Mexico City.
AB - Platelet-derived growth factor (PDGF) and its receptor system regulate
mesenchymal cell proliferation. We recently reported that emission-source fly-ash
particles and asbestos fibers induce the PDGF alpha-receptor through a macrophage
dependent pathway, and upregulation of this receptor greatly enhances the
mitogenic response of lung myofibroblasts to PDGF (Lindroos and colleagues, Am.
J. Respir. Cell Mol. Biol. 1997;16:283-292). In the present study we investigated
the effect of particulate matter <= 10 micrometers in size (PM10) from the
southern, central, and northern regions of Mexico City on PDGF receptor induction
and compared these urban, ambient particles with Mt. St. Helen's volcanic ash
particles as a negative control. All Mexico City PM10 samples, but not volcanic
ash, stimulated rat alveolar macrophages to secrete a soluble, upregulatory
factor(s) for the PDGF alpha-receptor on early passage rat lung myofibroblasts.
The macrophage-derived upregulatory activity was blocked by the interleukin (IL)
1 receptor antagonist. The ability of PM10 to stimulate IL-1beta release was
blocked in part by a recombinant endotoxin neutralizing protein (rENP).
Lipopolysaccharide/endotoxin (LPS) and vanadium, both constituents that were
present within these PM10 samples, also stimulated macrophages to secrete
factor(s) that upregulated PDGF-Ralpha on lung myofibroblasts. Direct exposure of
myofibroblasts to PM10 also elicited upregulation of the PDGF alpha-receptor, and
this effect was blocked by rENP and mimicked by LPS, but not vanadium. These
findings suggest that PM10 particles induce expression of the PDGF receptor
system through macrophage-dependent and -independent mechanisms involving
endotoxin and metals.
PMID- 9761766
TI - Identification and characterization of high molecular-mass mucin-like
glycoproteins in the plasma membrane of airway epithelial cells.
AB - A previous lectin binding study demonstrated the presence of high molecular-mass
mucin-like glycoproteins (HMGP) on the surface of hamster tracheal surface
epithelial (HTSE) secretory cells (Proc. Natl. Acad. Sci. USA 1987;84:9304). In
the present study, we intended to isolate and characterize these HMGP from the
plasma membrane of the primary HTSE cells and then to determine whether or not
these membrane HMGP are Muc-1 mucins, a type of mucins originally discovered on
the surface of some carcinomas. A subcellular fraction enriched with the plasma
membrane was obtained using a sucrose density gradient centrifugation. This
fraction contained high molecular-mass glycoconjugates which were excluded from
Sepharose CL-4B gel. Biochemical characterization of these glycoconjugates
revealed the following characteristics: (1) susceptibility to both pronase and
mild alkaline treatments, but totally resistant to proteoglycan-digesting
enzymes; (2) partitioning in the detergent phase of Triton X-114 and resistance
to digestion by phosphatidylinositol phospholipase C or D; (3) a buoyant density
of 1.5 g/ml based on CsCl density gradient centrifugation; (4) polydispersity in
terms of both size and charge density; and (5) lack of immunoreactivity with an
anti-Muc-1 mucin antibody. We conclude that the plasma membrane of HTSE cells at
confluence contains HMGP, which seem to be the integral membrane proteins but
different from Muc-1 mucins, and that these membrane HMGP appear to share some
similarities with secreted mucins in terms of size and charge.
PMID- 9761767
TI - Human eosinophils constitutively express a functional interleukin-4 receptor:
interleukin-4 -induced priming of chemotactic responses and induction of PI-3
kinase activity.
AB - Similar to interleukin-3 (IL-3), IL-5, and granulocyte macrophage colony
stimulating factor (GM-CSF), IL-4 can be secreted by several cell types involved
in allergic inflammatory reactions, and therefore can affect eosinophil function
similarly. In this study, we investigated the presence of an IL-4 receptor (IL
4R) on human eosinophils. When two different monoclonal antibodies (mAbs) against
the IL-4R alpha-chain (IL-4Ralpha) were used, fluorescent-activated cell sorter
analysis revealed the presence of an IL-4Ralpha on both eosinophils of normal
donors and atopic dermatitis patients. In addition, the expression of the IL-2R
gamma-chain, a functional component of the IL-4R in some cell types, was
demonstrated. The IL-4Ralpha appeared to be expressed constitutively, and
stimulation with cytokines IL-2, IL-3, IL-5, GM-CSF, and interferon-gamma did not
further increase IL-4Ralpha expression. Evidence for an IL-4Ralpha was further
substantiated by mRNA analysis. Both Northern blot analysis and reverse
transcriptase/polymerase chain reaction revealed the presence of mRNA for the IL
4Ralpha in eosinophils from normal individuals and AD patients. Furthermore, we
demonstrated that both IL-4 and IL-13 were capable of inducing PI-3 kinase
activity in human eosinophils. Because this activation could be inhibited by an
IL-4Ralpha mAb, we conclude that both cytokines can activate human eosinophils
through binding to a receptor complex comprising the IL-4Ralpha and-yet to be
identified-associated proteins. In addition, the involvement of IL-4 in
functional responses was studied. IL-4 appeared to "prime" eosinophils to respond
chemotactically toward regulated on activation, normal T cells expressed and
secreted, but did not affect platelet-activating factor-induced chemotaxis. Taken
together, these data show the presence of a functional IL-4R on human
eosinophils.
PMID- 9761769
TI - http://www.fasebj.org
PMID- 9761768
TI - Surfactant protein-A-deficient mice are susceptible to Pseudomonas aeruginosa
infection.
AB - To determine the role of surfactant protein-A (SP-A) in host defense, the murine
SP-A locus was targeted by homologous recombination to produce mice lacking SP-A.
SP-A-/- and wild-type mice were infected with mucoid Pseudomonas aeruginosa by
intratracheal instillation. Pulmonary bacterial loads were greater in SP-A-/-
than in wild-type mice, with increased numbers of mucoid P. aeruginosa in lung
homogenates at 6 and 24 h after infection. Pulmonary infiltration with
polymorphonuclear leukocytes (PMN) was similar in both groups; however, an
earlier influx of PMN into the lung occurred in the SP-A-/- mice. The number of
bacteria phagocytosed by alveolar macrophages was decreased in the SP-A-/- mice
at 1 h after infection. Superoxide-radical generation by PMN was similar for the
SP-A-/- and wild-type mice, but nitrite levels were increased in SP-A-/- mice.
Concentrations of tumor necrosis factor-alpha, interleukin-6, and macrophage
inflammatory protein-2 (proinflammatory cytokines) were greater in
bronchoalveolar lavage fluid at 2 h after infection in SP-A-/- mice. SP-A plays
an important role in the pathogenesis of mucoid P. aeruginosa infection in the
lung in vivo by enhancing macrophage phagocytosis and clearance of bacteria, and
by modifying the inflammatory response.
PMID- 9761770
TI - Molecular mimicry and immune-mediated diseases.
AB - Molecular mimicry has been proposed as a pathogenetic mechanism for autoimmune
disease, as well as a probe useful in uncovering its etiologic agents. The
hypothesis is based in part on the abundant epidemiological, clinical, and
experimental evidence of an association of infectious agents with autoimmune
disease and observed cross-reactivity of immune reagents with host 'self'
antigens and microbial determinants. For our purpose, molecular mimicry is
defined as similar structures shared by molecules from dissimilar genes or by
their protein products. Either the molecules' linear amino acid sequences or
their conformational fits may be shared, even though their origins are as
separate as, for example, a virus and a normal host self determinant. An immune
response against the determinant shared by the host and virus can evoke a tissue
specific immune response that is presumably capable of eliciting cell and tissue
destruction. The probable mechanism is generation of cytotoxic cross-reactive
effector lymphocytes or antibodies that recognize specific determinants on target
cells. The induction of cross-reactivity does not require a replicating agent,
and immune-mediated injury can occur after the immunogen has been removed a hit
and-run event. Hence, the viral or microbial infection that initiates the
autoimmune phenomenon may not be present by the time overt disease develops. By a
complementary mechanism, the microbe can induce cellular injury and release self
antigens, which generate immune responses that cross-react with additional but
genetically distinct self antigens. In both scenarios, analysis of the T cells or
antibodies specifically engaged in the autoimmune response and disease provides a
fingerprint for uncovering the initiating infectious agent.
PMID- 9761771
TI - Interactions between scatter factors and their receptors: hints for therapeutic
applications.
AB - The scatter factors, which include hepatocyte growth factor and macrophage
stimulating protein, stand out from other cytokines because of their uncommon
biological properties. In addition to promoting cell growth and protection from
apoptosis, they are involved in the control of cell dissociation, migration into
extracellular matrices, and a unique process of differentiation called 'branching
morphogenesis'. Through the concerted regulation of these complex phenomena,
scatter factors promote development, regeneration, and reconstruction of normal
organ architecture. In transformed epithelia, scatter factors can mediate tumor
invasive growth, a harmful feature of neoplastic progression in which cancer
cells invade surrounding tissues, penetrate across the vascular walls, and
eventually disseminate throughout the body, giving rise to systemic metastases. A
much-debated issue in basic biology, which has strong implications for
experimental medicine, is how to dissociate the favorable effects of growth
factors from their adverse ones. Accordingly, to find agonists or antagonists
with potential therapeutic applications is a crucial undertaking for current
research. Domain-mapping analyses of growth factor molecules can help to isolate
specific structural requirements for the induction of selective biological
effects. Based on the observation that certain growth factors must undergo
posttranslational modifications to exert a full response, it is possible to
interfere with their activation mechanisms to modulate their functions. Finally,
the identification of cell type-specific coreceptors able to potentiate their
activity allows drawing of a functional body map, where some organs or tissues
may be more responsive than others to growth factors. This review is focused on
how, and to what extent, scatter factors can behave 'well' or 'badly' according
to their molecular structure, the way they are activated, and the way they
interact with cell surface receptors and coreceptors.
PMID- 9761772
TI - Cys-scanning mutagenesis: a novel approach to structure function relationships in
polytopic membrane proteins.
AB - The entire lactose permease of Escherichia coli, a polytopic membrane transport
protein that catalyzes beta-galactoside/H+ symport, has been subjected to Cys
scanning mutagenesis in order to determine which residues play an obligatory role
in the mechanism and to create a library of mutants with a single-Cys residue at
each position of the molecule for structure/function studies. Analysis of the
mutants has led to the following: 1) only six amino acid side chains play an
irreplaceable role in the transport mechanism; 2) positions where the reactivity
of the Cys replacement is increased upon ligand binding are identified; 3)
positions where the reactivity of the Cys replacement is decreased by ligand
binding are identified; 4) helix packing, helix tilt, and ligand-induced
conformational changes are determined by using the library of mutants in
conjunction with a battery of site-directed techniques; 5) the permease is a
highly flexible molecule; and 6) a working model that explains coupling between
beta-galactoside and H+ translocation. structure-function relationships in
polytopic membrane proteins.
PMID- 9761773
TI - Tissue-specific effects of in vivo adenosine receptor blockade on glucose uptake
in Zucker rats.
AB - Previous studies have shown that treatment of obese Zucker rats with the
adenosine receptor antagonist 1,3-dipropyl-8-(p-acrylic) phenyl xanthine
(BWA1433) improves intraperitoneal glucose tolerance. In this study, a euglycemic
hyperinsulinemic clamp was performed on obese (fa/fa) and lean (Fa/fa) Zucker
rats that had been treated orally with BWA1433 or vehicle for 1 wk. A constant
infusion of [3H]glucose was initiated in fasted animals to measure basal whole
body glucose kinetics. No differences in glucose concentration or rates of
glucose production/disappearance were observed between lean or obese animals with
or without BWA1433. During the euglycemic hyperinsulinemic clamp, whole body
glucose disposal in obese Zucker rats was only 22% of that observed in lean
animals. BWA1433 treatment increased glucose disposal by 88% in obese Zucker
rats. At the end of the clamp, [14C]-2-deoxyglucose was injected to determine
tissue-specific differences in glucose uptake. Gastrocnemius, soleus, heart, and
liver of untreated obese animals had significantly lower glucose uptake than lean
controls under hyperinsulinemic conditions. BWA1433 treatment of obese animals
increased glucose uptake in gastrocnemius and soleus muscles by 44 and 47%,
respectively. Conversely, BWA1433 treatment decreased glucose uptake in adipose
tissue by 54 and 49% in obese and lean Zucker rats, respectively. In summary,
BWA1433 improves glucose tolerance by increasing glucose uptake in skeletal
muscle while decreasing glucose uptake by adipose tissue. This study suggests
that insulin resistance in obese Zucker rats is tissue specific and that
signaling from adenosine receptors may be a factor contributing to tissue
specific insulin resistance.
PMID- 9761774
TI - Characterization of human PLD2 and the analysis of PLD isoform splice variants.
AB - Phospholipase D (PLD) cleaves phosphatidylcholine in response to a variety of
cell stimuli to release phosphatidic acid, which is associated with a number of
cellular responses including regulated secretion, mitogenesis, and cytoskeletal
changes. Recent advances in this field include the reports of cDNA sequences for
two mammalian PLD isoforms: human PLD1 and rodent PLD2. We report the
characterization of cDNA encoding human PLD2. In these experiments, we uncovered
alternate splice variants of both human isoforms and evaluated the relative
abundance of these messages by reverse transcriptase polymerase chain reaction,
thereby indicating the physiologically relevant forms. Further, Northern
hybridization experiments defined the tissue distribution of the human PLD
messages. Human PLD1 does not appear to be an abundant message in any tissue
tested whereas levels of human PLD2 mRNA apparently were higher and more
variable. The specific activity and regulation of recombinant human PLD2 are
indistinguishable from that of recombinant mouse PLD2. Analysis of the amino acid
sequences of both human isoforms revealed important putative Pleckstrin homology
domains and identified additional members of the PLD gene family that help to
delimit the catalytic domain. The presence of Pleckstrin homology domains in the
PLDs resolves several contradictory observations regarding PLD regulation and the
domain structure of the proteins.
PMID- 9761775
TI - The amino acid transport system y+L/4F2hc is a heteromultimeric complex.
AB - 4F2hc is an almost ubiquitous transmembrane protein in mammalian cells; upon
expression in Xenopus laevis oocytes, it induces amino acid transport with
characteristics of system y+L. Indirect evidence fostered speculation that
function requires the association of 4F2hc with another protein endogenous to
oocytes and native tissues. We show that expression of system y+L-like amino acid
transport activity by 4F2hc in oocytes is limited by an endogenous factor and
that direct covalent modification of external cysteine residue(s) of an oocyte
membrane protein blocks system y+L/4F2hc transport activity, based on the
following. 1) Induction of system y+L-like activity saturates at very low doses
of human 4F2hc cRNA (0.1 ng/oocyte). This saturation occurs with very low
expression of 4F2hc at the oocyte surface, and further increased expression of
the protein at the cell surface does not result in higher induction of system y+L
like activity. 2) Human 4F2hc contains only two cysteine residues (C109 and
C330). We mutated these residues, singly and in combination, to serine (C109S;
CS1, C330S; CS2 and C109S-C330S, Cys-less). Mutation CS2 had no effect on the
expressed system y+L-like transport activity, whereas C109S-containing mutants
(CS1 and Cys-less) retained only partial y+L-like transport activity (30 to 50%
of wild type). 3) Hg2+, the organic mercury compounds pCMB, and the membrane
impermeant pCMBS almost completely inactivated system y+L-like induced by human
4F2hc wild type and all the mutants studied. This was reversed by ss
mercaptoethanol, indicating that external cysteine residue(s) are the target of
this inactivation. 4) Sensitivity to Hg2+ inactivation is increased by
pretreatment of oocytes with ss-mercaptoethanol or in the C109S-containing
mutants (CS1 and Cys-less). The increased Hg2+ reactivity of C109S-containing
mutants supports the possibility that C109 may be linked by a disulfide bond to
the Hg2+-targeted cysteine residue of the associated protein. These results
indicate that 4F2hc is intimately associated with a membrane oocyte protein for
the expression of system y+L amino acid transport activity. To our knowledge,
this is the first direct evidence for a heteromultimeric protein structure of an
organic solute carrier in mammals.
PMID- 9761776
TI - In vitro reconstruction of a human capillary-like network in a tissue-engineered
skin equivalent.
AB - For patients with extensive burns, wound coverage with an autologous in vitro
reconstructed skin made of both dermis and epidermis should be the best
alternative to split-thickness graft. Unfortunately, various obstacles have
delayed the widespread use of composite skin substitutes. Insufficient
vascularization has been proposed as the most likely reason for their unreliable
survival. Our purpose was to develop a vascular-like network inside tissue
engineered skin in order to improve graft vascularization. To reach this aim, we
fabricated a collagen biopolymer in which three human cell types keratinocytes,
dermal fibroblasts, and umbilical vein endothelial cells were cocultured. We
demonstrated that the endothelialized skin equivalent (ESE) promoted spontaneous
formation of capillary-like structures in a highly differentiated extracellular
matrix. Immunohistochemical analysis and transmission electron microscopy of the
ESE showed characteristics associated with the microvasculature in vivo (von
Willebrand factor, Weibel-Palade bodies, basement membrane material, and
intercellular junctions). We have developed the first endothelialized human
tissue-engineered skin in which a network of capillary-like tubes is formed. The
transplantation of this ESE on human should accelerate graft revascularization by
inosculation of its preexisting capillary-like network with the patient's own
blood vessels, as it is observed with autografts. In addition, the ESE turns out
to be a promising in vitro angiogenesis model.
PMID- 9761777
TI - Rapid insulinotropic effect of 17beta-estradiol via a plasma membrane receptor.
AB - Impaired insulin secretion is a hallmark in both type I and type II diabetic
individuals. Whereas type I (insulin-dependent diabetes mellitus) implies ss-cell
destruction, type II (non-insulin dependent diabetes mellitus), responsible for
75% of diabetic syndromes, involves diminished glucose-dependent secretion of
insulin from pancreatic beta-cells. Although a clear demonstration of a direct
effect of 17beta-estradiol on the pancreatic ss-cell is lacking, an in vivo
insulinotropic effect has been suggested. In this report we describe the effects
of 17beta-estradiol in mouse pancreatic ss-cells. 17beta-Estradiol, at
physiological concentrations, closes K(ATP) channels, which are also targets for
antidiabetic sulfonylureas, in a rapid and reversible manner. Furthermore, in
synergy with glucose, 17beta-estradiol depolarizes the plasma membrane, eliciting
electrical activity and intracellular calcium signals, which in turn enhance
insulin secretion. These effects occur through a receptor located at the plasma
membrane, distinct from the classic cytosolic estrogen receptor. Specific
competitive binding and localization of 17beta-estradiol receptors at the plasma
membrane was demonstrated using confocal reflective microscopy and
immunocytochemistry. Gaining deeper knowledge of the effect induced by 17beta
estradiol may be important in order to better understand the hormonal regulation
of insulin secretion and for the treatment of NIDDM. receptor.
PMID- 9761778
TI - Targeting of gliadin peptides, CD8, alpha/beta-TCR, and gamma/delta-TCR to Golgi
complexes and vacuoles within celiac disease enterocytes.
AB - Celiac disease (CD) is characterized by autodestruction of enterocytes after
exposure of genetically susceptible individuals to dietary gluten. To define the
transport pathways of proteins involved in the celiac immune response, we wished
to determine the subcellular compartments of the intestinal mucosa where wheat
gliadin peptides colocalize with receptors of T lymphocytes, including alpha/beta
TCR, gamma/delta-TCR, and CD8. Semithin and ultrathin frozen section of jejunal
biopsies from CD patients and controls were used to perform immunofluorescence
and immunogold labeling as well as in situ hybridization experiments. In patients
with active CD, we detected gliadin peptides in vacuoles and Golgi complexes of
enterocytes. CD8, alpha/beta-TCR, and gamma/delta-TCR were found in vacuoles and
Golgi complexes within these gliadin-containing enterocytes in addition to the
surface of intraepithelial and mucosal T lymphocytes. In contrast, we observed
that the localization of CD4, CD3, T cell-restricted intracellular antigen (TIA),
and leukocyte common antigen (LCA) was restricted to lymphocytes in CD patients.
We further detected labeling signals for gliadin peptides, CD8, alpha/beta-TCR,
and gamma/delta-TCR at the basal membrane of enterocytes that were interdigitated
by extensions of lymphocytes. In situ hybridization experiments revealed that CD8
and gamma/delta-TCR were not expressed by CD enterocytes. We conclude that CD8,
alpha/beta-TCR, and gamma/delta-TCR are targeted to Golgi complexes and vacuoles
of small intestinal enterocytes in active CD. The observed process may be
involved in the pathogenesis of CD enterocytes. We propose a mechanism for the
uptake of CD8, alpha/beta-TCR, and gamma/delta-TCR by the basolateral membrane of
small intestinal enterocytes.
PMID- 9761779
TI - Testosterone mediates expression of the selenoprotein PHGPx by induction of
spermatogenesis and not by direct transcriptional gene activation.
AB - Selenium deficiency is known to be associated with male infertility, and the
selenoprotein PHGPx has been shown to increase in rat testis after puberty and to
depend on gonadotropin stimulation in hypophysectomized rats [Roveri et al.
(1992) J. Biol. Chem. 267, 6142 6146]. Exposure of decapsulated whole testis,
however, failed to reveal any transcriptional activation or inhibition of the
PHGPx gene by testosterone, human chorionic gonadotropin, or forskolin.
Nevertheless, it was verified that the specific activity of PHGPx in testis, but
not of cGPx, correlated with sexual maturation. Leydig cell destruction in vivo
by ethane dimethane sulfonate (EDS) resulted in a delayed decrease in PHGPx
activity and mRNA that could be completely prevented by testosterone
substitution. cGPx transiently increased upon EDS treatment, probably as a result
of reactive macrophage augmentation. In situ mRNA hybridization studies
demonstrated an uncharacteristic low level of cGPx transcription in testis,
whereas PHGPx mRNA was abundantly and preferentially expressed in round
spermatids. The data show that the age or gonadotropin-dependent expression of
PHGPx in testis does not result from direct transcriptional gene activation by
testosterone, but is due to differentiation stage-specific expression in late
spermatids, which are under the control of Leydig cell-derived testosterone. The
striking burst of PHGPx expression at the transition of round to elongated
spermatids suggests an involvement of this selenoprotein in sperm maturation.
PMID- 9761780
TI - Induction of the stress response with prostaglandin A1 increases I-kappaBalpha
gene expression.
AB - I-kappaBalpha is an intracellular protein that functions as a primary inhibitor
of the proinflammatory transcription factor NF-kappaB. Induction of the stress
response with heat shock was previously demonstrated to induce I-kappaBalpha gene
expression. Because the stress response can also be induced by nonthermal
stimuli, we determined whether induction of the stress response with
prostaglandin A1 (PGA1) would induce I-kappaBalpha gene expression. Treatment of
human bronchial epithelium (BEAS-2B cells) with PGA1 induced nuclear
translocation of heat shock factor 1, thus confirming that PGA1 induces the
stress response in BEAS-2B cells. Induction of the stress response with PGA1
increased I-kappaBalpha mRNA expression in a time-dependent manner and increased
I-kappaBalpha peptide expression. Transient transfection assays involving a human
I-kappaBalpha promoter-luciferase reporter construct demonstrated that induction
of the stress response with PGA1 activated the I-kappaBalpha promoter. Induction
of the stress response with PGA1 and concomitant induction of I-kappaBalpha were
associated with inhibition of TNF-alpha-mediated secretion of interleukin 8 and
with inhibition of TNF-alpha-mediated nuclear translocation and activation of NF
kappaB. These data demonstrate that induction of the stress response, by a
nonthermal stimulus, increases I-kappaBalpha gene expression by a mechanism
involving activation of the I-kappaBalpha promoter. Coupled with previous data
demonstrating heat shock-mediated induction of I-kappaBalpha gene expression,
these data suggest that I-kappaBalpha may be considered to be one of the stress
proteins. The functional consequences of stress response-mediated I-kappaBalpha
gene expression may involve attenuation of cellular proinflammatory responses.
PMID- 9761781
TI - Divergent effects of exercise on metabolic and mitogenic signaling pathways in
human skeletal muscle.
AB - The molecular signaling mechanisms by which muscle contractions lead to changes
in glucose metabolism and gene expression remain largely undefined. We assessed
whether exercise activates MAP kinase proteins (ERK1/2, SEK1, and p38 MAP kinase)
as well as Akt and PYK2 in skeletal muscle from healthy volunteers obtained
during and after one-leg cycle ergometry at approximately 70% VO2max. Exercise
led to a marked increase in ERK1/2 phosphorylation, which rapidly decreased to
resting levels upon recovery. Exercise increased phosphorylation of SEK1 and p38
MAP kinase to a lesser extent than ERK1/2. In contrast to ERK1/2, p38 MAP kinase
phosphorylation was increased in nonexercised muscle upon cessation of exercise.
Phosphorylation of the transcription factor CREB was increased in nonexercised
muscle upon cessation of exercise. Exercise did not activate Akt or increase
tyrosine phosphorylation of PYK2. Thus, exercise has divergent effects on
parallel MAP kinase pathways, of which only p38 demonstrated a systemic response.
However, our data do not support a role of Akt or PYK2 in exercise/contraction
induced signaling in human skeletal. Activation of the different MAP kinase
pathways by physical exercise appears to be important in the regulation of
transcriptional events in skeletal muscle.
PMID- 9761782
TI - The agouti gene product inhibits lipolysis in human adipocytes via a Ca2+
dependent mechanism.
AB - Overexpression of the murine agouti gene results in obesity. The human homologue
of agouti is expressed primarily in human adipocytes, and we have shown
recombinant agouti protein to increase adipocyte intracellular Ca2+([Ca2+]i) and
thereby stimulate lipogenesis. However, since recent data demonstrate that
increasing adipocyte [Ca2+]i may also inhibit lipolysis, we have investigated the
role of agouti-induced [Ca2+]i increases in regulating lipolysis in human
adipocytes. Short-term (1 h) exposure to recombinant agouti (100 nM) protein had
no effect on basal lipolysis, although longer term treatment (24 h) caused a 60%
decrease in basal lipolysis (P<0.0001). Short-term agouti treatment totally
inhibited ACTH-induced lipolysis (P<0.05). Since melanocortin receptors (MCR) are
involved in some actions of agouti, we next determined whether agouti's
antilipolytic effect is exerted through competitive antagonism of the ACTH
receptor (MCR-2). Forskolin (1 microM), an adenylate cyclase activator, induced a
48% increase in lipolysis in human adipocytes (P<0.05); this effect was reversed
by 100 nM agouti (P<005), demonstrating that the antilipolytic effect of agouti
is distal to the ACTH receptor. To determine the role of [Ca2+]i in the
antilipolytic effect of agouti, human adipocytes were treated with KCl or
arginine vasopressin to stimulate voltage- and receptor-stimulated Ca2+ influx,
respectively. Both agents caused inhibition of forskolin-induced lipolysis
(P<0.005). Furthermore, agouti's antilipolytic effect was also blocked by the
Ca2+ channel blocker nitrendipine. These data demonstrate that agouti exerts a
potent antilipolytic effect in human adipocytes via a Ca2+-dependent mechanism.
This effect, combined with agouti-induced lipogenesis, represents a coordinate
control of adipocyte lipid metabolism that may contribute to an agouti-induced
obesity syndrome.
PMID- 9761783
TI - Oxidative DNA damage measured in human lymphocytes: large differences between
sexes and between countries, and correlations with heart disease mortality rates.
AB - The 'antioxidant hypothesis' proposes that vitamin C, vitamin E, carotenoids, and
other antioxidants occurring in fruit and vegetables afford protection against
heart disease and cancer by preventing oxidative damage to lipids and to DNA,
respectively. To test elements of this hypothesis, we have measured blood levels
of dietary antioxidants, and 8-oxodeoxyguanosine (8-oxo-dG) concentrations in
lymphocyte DNA, in healthy men and women from five European countries: France,
Ireland, The Netherlands, Spain, and the U.K. Volunteers, aged 25 45, all
nonsmokers, gave blood samples before and after a 12-wk carotenoid
supplementation regime. Vitamin C was measured in plasma and vitamin E and
carotenoids were measured in serum by high-performance liquid chromatography
(HPLC). 8-oxo-dG was assayed by HPLC (with coulometric detection) in DNA isolated
from lymphocytes from the same blood samples. Mean values were calculated for
groups of volunteers at each sampling time according to country, sex, and
supplementation (between 9 and 24 individual samples contributing to each mean).
We found that 8-oxo-dG levels in lymphocyte DNA vary significantly according to
sex and country. A low mean 8-oxo-dG concentration is seen in DNA of women from
all five countries, and of men from France and Spain. 8-oxo-dG is significantly
higher (up to about threefold) in lymphocyte DNA from men in Ireland and the U.K.
Oxidative DNA damage is not significantly affected by carotenoid supplementation;
nor is there any association with mean baseline levels of antioxidants, which are
generally similar in the five countries. The five countries sampled lie on an
axis from northern to southern Europe with a steep gradient in terms of premature
heart disease. There is a strong association between premature coronary heart
disease mortality in men and the mean levels of 8-oxo-dG for the five countries
(r = 0.95, P < 0.01). Women have low coronary heart disease mortality rates,
which do not correlate with 8-oxo-dG. In terms of cancer deaths, only colorectal
cancer in men shows a significant positive correlation (r = 0.91, P < 0.05), and
stomach cancer in women is negatively correlated with DNA oxidation (r = -0.92, P
= 0.01).
PMID- 9761784
TI - Membrane-bound calmodulin in Xenopus laevis oocytes as a novel binding site for
melatonin.
AB - Melatonin has been suggested as a physiological antagonist of calmodulin. In this
work, we have characterized melatonin binding sites in Xenopus laevis oocyte
membranes. Binding of [125I]melatonin by X. laevis oocyte membranes fulfills all
criteria for binding to a receptor site. Binding was dependent on time,
temperature, and membrane concentration and was stable, reversible, saturable,
and specific. The binding site was also pharmacologically characterized.
Stoichiometric studies showed a high-affinity binding site with a Kd of 1.18 nM.
These data are in close agreement with data obtained from kinetic studies
(Kd=0.12 nM). In competition studies, we observed a low-affinity binding site
(Kd=63.41 microM). Moreover, the binding site was characterized as calmodulin.
Thus, binding was dependent on calcium and blocked by anti-CaM antibodies in a
concentration-dependent manner. Calmodulin inhibitor chlorpromazine also
inhibited binding of the tracer. From these results, it is suggested that
membrane-bound calmodulin acts as a melatonin binding site in Xenopus laevis
oocytes, where it might couple cellular activities to rhythmic circulating levels
of melatonin. This hypothesis correlates with the previous findings describing
melatonin as a physiological antagonist of calmodulin.
PMID- 9761785
TI - Putative susceptibility markers of coronary artery disease: association between
VDR genotype, smoking, and aromatic DNA adduct levels in human right atrial
tissue.
AB - Cancer and cardiovascular diseases share risk factors such as smoking, and the
onset of both diseases have been suggested to have a common mechanistic basis.
The binding of carcinogens to DNA (carcinogen-DNA adducts), genetic polymorphisms
in carcinogen-detoxifying enzymes glutathione S-transferases (GSTs), and genetic
polymorphisms in the vitamin D receptor (VDR) are among the candidates for
modifiers of cancer risk. We determined whether these biomarkers could be related
to individual characteristics of patients suffering from cardiovascular diseases.
For that purpose, DNA from the right atrial appendage of 41 patients who
underwent open heart surgery was analyzed for smoking-related DNA adducts and
polymorphisms in GSTM1, GSTT1, and VDR genes. Statistical analysis was used to
identify any patient's characteristics associated with these molecular markers.
Our results showed that heart tissue of cigarette smokers contained a variety of
aromatic DNA adducts in significantly elevated levels compared to ex-smokers
(P<0.01) or nonsmokers (P<0.001). A linear relationship was observed between DNA
adduct levels and daily cigarette smoking (rs=0.73; P=0.0003). Since cardiac
myocytes are terminally differentiated cells that have lost their ability to
divide and seemingly have limited DNA repair capacities, their levels might
accumulate with time and thereby affect heart cell function or viability.
Substantial interindividual differences between DNA adduct levels were observed,
and persons with severe coronary artery disease (CAD), as assessed by coronary
angiography, had higher DNA adduct levels than persons with no or mild CAD
(P=0.04). As polymorphisms in GST genes have been shown to modulate DNA adduct
levels and risk for lung cancer in smokers, we explored for the first time
whether the GST polymorphisms could also explain deviating heart DNA adduct
levels and CAD risk. However, no relation could be found between these
covariants. In contrast, a VDR genotype, which has been associated with decreased
serum levels of the active hormonal form of vitamin D and increased risk for
certain cancers, seemed to be related to severity of CAD (P=0.025). Our findings
support the hypothesis that smoking-related DNA damage may be involved in the
onset of cardiovascular diseases and suggest that VDR genotype may be a useful
susceptibility marker of CAD.
PMID- 9761787
TI - Auxin signaling. Homing In with targeted genetics
PMID- 9761786
TI - In vitro modulation of primate coronary vascular muscle cell reactivity by
ovarian steroid hormones.
AB - Susceptibility to drug-induced coronary vasospasm in rhesus monkeys increases
after removal of the ovaries and can be normalized by adding back physiological
levels of estradiol-17ss (E2) and/or natural progesterone (P) in vivo as reported
recently by our group. Furthermore, the reactivity status (Ca2+ and protein
kinase C responses) of freshly isolated and primary culture coronary artery
vascular muscle cells (VMC) mimic the intact coronary artery responses to 5-HT +
U46619. Since coronary reactivity is maintained in the isolated VMC, we
hypothesized that the reactivity state inherent in the VMC was modulated directly
by ovarian steroids in vitro as in the whole animal. To test this hypothesis, we
treated hyperreactive VMC from ovariectomized (ovx) monkeys in vitro with E2 or P
and measured VMC reactivity to combined stimulation with 5-HT and U46619, as
determined by the amplitude and especially the duration of intracellular Ca2+
signals, as well as protein kinase C (PKC) activation/translocation. VMC were
treated for 12 96 h with 3 100 pg/ml E2 (10 365 pM) and/or 0.3 3 ng/ml P (0.95
9.5 nM). Hyperreactive responses to the combination of 5-HT and U46619 in
untreated VMC were significantly and dose-dependently reduced by treatment in
vitro with physiological levels of either E2 or P for at least 24 h. Both the
early transient and late sustained increases in intracellular Ca2+ and PKC
translocation were blunted, and the effects of 0.2 nM E2 and 3.2 nM P were
specifically antagonized by the receptor blockers ICI 182,780 (200 nM) and RU486
(15 nM), respectively. Antibodies to the estrogen receptor and progesterone
receptor labeled nuclei in VMC, which were also positively labeled by a smooth
muscle myosin heavy chain monoclonal antibody. These data indicate that natural
ovarian steroids directly reduce hyperreactive 5-HT and thromboxane A2-stimulated
Ca2+ and PKC responses of coronary artery VMC from surgically menopausal rhesus
macaques. We hypothesize that vascular hyperreactivity, which may be a critical
factor involved in the increased incidence of coronary artery vasospasm and
ischemic heart disease in postmenopausal women, can be normalized by E2 and/or P
through direct actions on coronary artery vascular muscle cells.
PMID- 9761788
TI - Nodule parenchyma-specific expression of the sesbania rostrata early nodulin gene
SrEnod2 is mediated by its 3' untranslated region
AB - The early nodulin Enod2 gene encodes a putative hydroxyproline-rich cell wall
protein and is expressed exclusively in the nodule parenchyma cell layer. The
latter finding suggests that the Enod2 protein may contribute to the special
morphological features of the nodule parenchyma and to the creation of an oxygen
diffusion barrier. The Enod2 gene of the stem-nodulating legume Sesbania rostrata
(SrEnod2) is induced specifically in roots by the plant hormone cytokinin, and
this induction occurs at a post-transcriptional level. Here, we characterize the
cis determinant(s) in the SrEnod2 locus responsible for nodule parenchyma
specific expression and show that the 3' untranslated region (UTR) of the SrEnod2
gene is both required and sufficient for directing chimeric reporter gene
expression in the nodule parenchyma of transgenic Lotus corniculatus plants.
Moreover, we show that the SrEnod2 3' UTR does not act as a tissue-specific
enhancer element. By conducting a detailed deletion analysis of the 5' and 3'
SrEnod2 regions, we delimited the minimal promoter of the SrEnod2 gene, and it
appears that the 5' flanking sequences are not essential for nodule parenchyma
specific expression. This finding is in contrast with the report that the 5'
upstream region of the soybean Enod2 gene directs nodule parenchyma-specific
expression, indicating that different mechanisms may be involved in regulating
the expression of these two genes. We definitively demonstrate that the cis
element(s) for tissue-specific expression is located within the 3' UTR of a plant
nuclear gene.
PMID- 9761789
TI - Ribozymes targeted to stearoyl-ACP delta9 desaturase mRNA produce heritable
increases of stearic acid in transgenic maize leaves.
AB - Ribozymes are RNAs that can be designed to catalyze the specific cleavage or
ligation of target RNAs. We have explored the possibility of using ribozymes in
maize to downregulate the expression of the stearoyl-acyl carrier protein
(Delta9) desaturase gene. Based on site accessibility and catalytic activity,
several ribozyme constructs were designed and transformed into regenerable maize
lines. One of these constructs, a multimer hammerhead ribozyme linked to a
selectable marker gene, was shown to increase leaf stearate in two of 13 maize
lines. There were concomitant decreases in Delta9 desaturase mRNA and protein.
The plants with the altered stearate phenotype were shown to express ribozyme
RNA. The ribozyme-mediated trait was heritable, as evidenced by stearate
increases in the leaves of the R1 plants derived from a high-stearate line. The
increase in stearate correlated with the presence of the ribozyme gene. A
catalytically inactive version of this ribozyme did not produce any significant
effect in transgenic maize. This is evidence that ribozymes can be used to
modulate the expression of endogenous genes in maize.
PMID- 9761790
TI - Involvement of an ABC transporter in a developmental pathway regulating hypocotyl
cell elongation in the light
AB - In the dark, plant seedlings follow the skotomorphogenetic developmental program,
which results in hypocotyl cell elongation. When the seedlings are exposed to
light, a switch to photomorphogenetic development occurs, and hypocotyl cell
elongation is inhibited. We have manipulated the expression of the AtPGP1 (for
Arabidopsis thaliana P glycoprotein1) gene in transgenic Arabidopsis plants by
using sense and antisense constructs. We show that within a certain light fluence
rate window, overexpression of the AtPGP1 gene under the control of the
cauliflower mosaic virus 35S promoter causes plants to develop longer hypocotyls,
whereas expression of the gene in antisense orientation results in hypocotyls
shorter than those occurring in the wild type. In the dark, hypocotyls of
transgenic and wild-type plants are indistinguishable. Because the AtPGP1 gene
encodes a member of the superfamily of ATP binding cassette-containing (ABC)
transporters, these results imply that a transport process is involved in a
hypocotyl cell elongation pathway active in the light. The AtPGP1 transporter is
localized in the plasmalemma, as indicated by immunohistochemical techniques and
biochemical membrane separation methods. Analysis of the AtPGP1 expression
pattern by using reporter gene constructs and in situ hybridization shows that in
wild-type seedlings, AtPGP1 is expressed in both the root and shoot apices.
PMID- 9761791
TI - The plant U1 small nuclear ribonucleoprotein particle 70K protein interacts with
two novel serine/arginine-rich proteins.
AB - The U1 small nuclear ribonucleoprotein particle (U1 snRNP) 70K protein (U1-70K),
one of the three U1 snRNP-specific proteins, is implicated in basic and
alternative splicing of nuclear pre-mRNAs. We have used the Arabidopsis U1-70K in
the yeast two-hybrid system to isolate cDNAs encoding proteins that interact with
it. This screening has resulted in the isolation of two novel plant
serine/arginine-rich (SR) proteins, SRZ-22 and SRZ-21 (SRZ proteins). Neither the
N-terminal region nor the arginine-rich C-terminal region of U1-70K alone
interact with the SRZ proteins. The interaction of U1-70K with the SRZ proteins
is confirmed further in vitro using a blot overlay assay. The plant SRZ proteins
are highly similar to each other and contain conserved modular domains unique to
different groups of splicing factors in the SR family of proteins. SRZ proteins
are similar to human 9G8 splicing factor because they contain a zinc knuckle,
precipitate with 65% ammonium sulfate, and cross-react with the 9G8 monoclonal
antibody. However, unlike the 9G8 splicing factor, SRZ proteins contain a glycine
hinge, a unique feature in other splicing factors (SC35 and ASF/SF2), located
between the RNA binding domain and the zinc knuckle. SRZ-22 and SRZ-21 are
encoded by two distinct genes and are expressed in all tissues tested with varied
levels of expression. Our results suggest that the plant SRZ proteins represent a
new group of SR proteins. The interaction of plant U1-70K with the SRZ proteins
may account for some differences in pre-mRNA splicing between plants and animals.
PMID- 9761792
TI - age Mutants of Arabidopsis exhibit altered auxin-regulated gene expression.
AB - An Arabidopsis transgenic line was constructed expressing beta-glucuronidase
(GUS) via the auxin-responsive domains (AuxRDs) A and B (BA-GUS) of the PS-IAA4/5
gene in an indoleacetic acid (IAA)-dependent fashion. GUS expression was
preferentially enhanced in the root elongation zone after treatment of young
seedlings with 10(-7) M IAA. Expression of the BA-GUS gene in the axr1, axr4, and
aux1 mutants required 10- to 100-fold higher auxin concentration than that in the
wild-type background. GUS expression was nil in the axr 2 and axr 3 mutants. The
transgene was used to isolate mutants exhibiting altered auxin-responsive gene
expression (age). Two mutants, age1 and age2, were isolated and characterized.
age1 showed enhanced sensitivity to IAA, with strong GUS expression localized in
the root elongation zone in the presence of 10(-8) M IAA. In contrast, age2
exhibited ectopic GUS expression associated with the root vascular tissue, even
in the absence of exogenous IAA. Morphological and molecular analyses indicated
that the age1 and age2 alleles are involved in the regulation of gene expression
in response to IAA.
PMID- 9761793
TI - Photoinduction of flower identity in vegetatively biased primordia.
AB - Far-red light and long photoperiods promote flowering in Arabidopsis. We report
here that when 30-day-old vegetative plants were induced with a continuous light
treatment enriched in far-red light, flowers developed directly from previously
initiated primordia. Specifically, plants induced with our continuous
incandescent-enriched (CI) treatment produced an average of two primary-axis
nodes with a leaf/flower phenotype, indicating that approximately two
leaf/paraclade primordia per plant produced an individual flower from tissue that
typically would differentiate into a paraclade (secondary inflorescence). Assays
for APETALA1::beta-glucuronidase activity during the CI photoinduction treatment
indicated that the floral meristem identity gene APETALA1 was transcriptionally
activated in primordia with a leaf/paraclade bias and in primordia committed to
leaf/paraclade development. APETALA1::beta-glucuronidase activity levels were
initially highest in young primordia but were not correlated strictly with
primordium fate. These results indicate that primordium fate can be modified
after primordium initiation and that developing primordia respond quantitatively
to floral induction signals.
PMID- 9761794
TI - The Arabidopsis DIMINUTO/DWARF1 gene encodes a protein involved in steroid
synthesis.
AB - We have identified the function of the Arabidopsis DIMINUTO/DWARF1 (DIM/DWF1)
gene by analyzing the dim mutant, a severe dwarf with greatly reduced fertility.
Both the mutant phenotype and gene expression could be rescued by the addition of
exogenous brassinolide. Analysis of endogenous sterols demonstrated that dim
accumulates 24-methylenecholesterol but is deficient in campesterol, an early
precursor of brassinolide. In addition, we show that dim is deficient in
brassinosteroids as well. Feeding experiments using deuterium-labeled 24
methylenecholesterol and 24-methyldesmosterol confirmed that DIM/DWF1 is involved
in both the isomerization and reduction of the Delta24(28) bond. This conversion
is not required in cholesterol biosynthesis in animals but is a key step in the
biosynthesis of plant sterols. Transient expression of a green fluorescent
protein-DIM/DWF1 fusion protein and biochemical experiments showed that DIM/DWF1
is an integral membrane protein that most probably is associated with the
endoplasmic reticulum.
PMID- 9761795
TI - Developmental control of telomere lengths and telomerase activity in plants.
AB - Telomere lengths and telomerase activity were studied during the development of a
model dioecious plant, Melandrium album (syn Silene latifolia). Telomeric DNA
consisted of Arabidopsis-type TTTAGGG tandem repeats. The terminal positions of
these repeats were confirmed by both Bal31 exonuclease degradation and in situ
hybridization. Analysis of terminal restriction fragments in different tissues
and ontogenetic stages showed that telomere lengths are stabilized precisely and
do not change during plant growth and development. Telomerase activity tested by
using a semiquantitative telomerase repeat amplification protocol correlated with
cell proliferation in the tissues analyzed. Highest activity was found in
germinating seedlings and root tips, whereas we observed a 100-fold decrease in
telomerase activity in leaves and no activity in quiescent seeds. Telomerase also
was found in mature pollen grains. Telomerase activity in tissues containing
dividing cells and telomere length stability during development suggest their
precise control during plant ontogenesis; however, the telomere length regulation
mechanism could be unbalanced during in vitro dedifferentiation.
PMID- 9761796
TI - A mutant of Arabidopsis lacking a chloroplastic isoamylase accumulates both
starch and phytoglycogen.
AB - In this study, our goal was to evaluate the role of starch debranching enzymes in
the determination of the structure of amylopectin. We screened mutant populations
of Arabidopsis for plants with alterations in the structure of leaf starch by
using iodine staining. The leaves of two mutant lines stained reddish brown,
whereas wild-type leaves stained brownish black, indicating that a more highly
branched polyglucan than amylopectin was present. The mutants were allelic, and
the mutation mapped to position 18.8 on chromosome 1. One mutant line lacked the
transcript for a gene with sequence similarity to higher plant debranching
enzymes, and both mutants lacked a chloroplastic starch-hydrolyzing enzyme. This
enzyme was identified as a debranching enzyme of the isoamylase type. The loss of
this isoamylase resulted in a 90% reduction in the accumulation of starch in this
mutant line when compared with the wild type and in the accumulation of the
highly branched water-soluble polysaccharide phytoglycogen. Both normal starch
and phytoglycogen accumulated simultaneously in the same chloroplasts in the
mutant lines, suggesting that isoamylase has an indirect rather than a direct
role in determining amylopectin structure.
PMID- 9761797
TI - rbcL Transcript levels in tobacco plastids are independent of light: reduced dark
transcription rate is compensated by increased mRNA stability.
AB - The plastid rbcL gene, encoding the large subunit of ribulose-1, 5-bisphosphate
carboxylase, in higher plants is transcribed from a sigma70 promoter by the
eubacterial-type RNA polymerase. To identify regulatory elements outside of the
rbcL -10/-35 promoter core, we constructed transplastomic tobacco plants with
uidA reporter genes expressed from rbcL promoter derivatives. Promoter activity
was characterized by measuring steady state levels of uidA mRNA on RNA gel blots
and by measuring promoter strength in run-on transcription assays. We report here
that the rbcL core promoter is sufficient to obtain wild-type rates of
transcription. Furthermore, the rates of transcription were up to 10-fold higher
in light-grown leaves than in dark-adapted plants. Although the rates of
transcription were lower in the dark, rbcL mRNA accumulated to similar levels in
light-grown and dark-adapted leaves. Accumulation of uidA mRNA from most rbcL
promoter deletion derivatives directly reflected the relative rates of
transcription: high in the light-grown and low in the dark-adapted leaves.
However, uidA mRNA accumulated to high levels in a light-independent fashion as
long as a segment encoding a stem-loop structure in the 5' untranslated region
was included in the promoter construct. This finding indicates that lower rates
of rbcL transcription in the dark are compensated by increased mRNA stability.
PMID- 9761798
TI - Identification of residues in a hydrophilic loop of the Papaver rhoeas S protein
that play a crucial role in recognition of incompatible pollen.
AB - The self-incompatibility response involves S allele-specific recognition between
stigmatic S proteins and incompatible pollen. This response results in pollen
inhibition. Defining the amino acid residues within the stigmatic S proteins that
participate in S allele-specific inhibition of incompatible pollen is essential
for the elucidation of the molecular basis of the self-incompatibility response.
We have constructed mutant derivatives of the S1 protein from Papaver rhoeas by
using site-directed mutagenesis and have tested their biological activity. This
has enabled us to identify amino acid residues in the stigmatic S proteins of P.
rhoeas that are required for S-specific inhibition of incompatible pollen. We
report here the identification of several amino acid residues in the predicted
hydrophilic loop 6 of the P. rhoeas stigmatic S1 protein that are involved in the
inhibition of S1 pollen. Mutation of the only hypervariable amino acid, which is
situated in this loop, resulted in the complete loss of ability of the S protein
to inhibit S1 pollen. This clearly demonstrates that this residue plays a crucial
role in pollen recognition and may also participate in defining allelic
specificity. We have also established the importance of highly conserved amino
acids adjacent to this hypervariable site. Our studies demonstrate that both
variable and conserved amino acids in the region of the S protein corresponding
to surface loop 6 are key elements that play a role in the recognition and
inhibition of incompatible pollen in the pollen-pistil self-incompatibility
reaction.
PMID- 9761799
TI - Inefficient reinitiation is responsible for upstream open reading frame-mediated
translational repression of the maize R gene.
AB - Maize R genes encode a small family of transcriptional activators of several
structural genes in the anthocyanin biosynthetic pathway. The 5' leader region of
most R genes contains a 38-codon upstream open reading frame (uORF) that
previously was shown to be responsible for the repression of downstream gene
expression in a transient transformation assay. In this study, we report that the
5' leader also can repress translation of the downstream luciferase gene both in
the rabbit reticulocyte translation system and in transgenic rice plants. The
ability to visualize the uORF peptide after in vitro translation permits
quantification of both products of dicistronic mRNAs. Similarly, the construction
of transgenic rice plants expressing wild-type and mutant constructs permits the
quantification and correlation of steady state mRNA levels and reporter gene
activities. Using these assays, we demonstrate directly that translation of the
uORF is required for repression, that increasing translation of the uORF peptide
decreases downstream gene expression, and that repression is unaffected by either
subtle or gross changes in the uORF peptide. Rather, we find that ribosomes that
translate the uORF reinitiate inefficiently and that the intercistronic sequence
downstream of the uORF mediates this effect.
PMID- 9761800
TI - Arabidopsis mutants impaired in cosuppression.
AB - Post-transcriptional gene silencing (cosuppression) results in the degradation of
RNA after transcription. A transgenic Arabidopsis line showing post
transcriptional silencing of a 35S-uidA transgene and uidA-specific methylation
was mutagenized using ethyl methanesulfonate. Six independent plants were
isolated in which uidA mRNA accumulation and beta-glucuronidase activity were
increased up to 3500-fold, whereas the transcription rate of the 35S-uidA
transgene was increased only up to threefold. These plants each carried a
recessive monogenic mutation that is responsible for the release of silencing.
These mutations defined two genetic loci, called sgs1 and sgs2 (for suppressor of
gene silencing). Transgene methylation was distinctly modified in sgs1 and sgs2
mutants. However, methylation of centromeric repeats was not affected, indicating
that sgs mutants differ from ddm (for decrease in DNA methylation) and som (for
somniferous) mutants. Indeed, unlike ddm and som mutations, sgs mutations were
not able to release transcriptional silencing of a 35S-hpt transgene. Conversely,
both sgs1 and sgs2 mutations were able to release cosuppression of host Nia genes
and 35S-Nia2 transgenes. These results therefore indicate that sgs mutations act
in trans to impede specifically transgene-induced post-transcriptional gene
silencing.
PMID- 9761801
TI - Targeting of active sialyltransferase to the plant Golgi apparatus.
AB - Glycosyltransferases in the Golgi apparatus synthesize cell wall polysaccharides
and elaborate the complex glycans of glycoproteins. To investigate the targeting
of this type of enzyme to plant Golgi compartments, we generated transgenic
Arabidopsis plants expressing alpha-2,6-sialyltransferase, a glycosyltransferase
of the mammalian trans-Golgi cisternae and the trans-Golgi network. Biochemical
analysis as well as immunolight and immunoelectron microscopy of these plants
indicate that the protein is targeted specifically to the Golgi apparatus.
Moreover, the protein is predominantly localized to the cisternae and membranes
of the trans side of the organelle. When supplied with the appropriate
substrates, the enzyme has significant alpha-2,6-sialyltransferase activity.
These results indicate a conservation of glycosyltransferase targeting mechanisms
between plant and mammalian cells and also demonstrate that glycosyltransferases
can be subcompartmentalized to specific cisternae of the plant Golgi apparatus.
PMID- 9761802
TI - A comparison of active and simulated chiropractic manipulation as adjunctive
treatment for childhood asthma.
AB - BACKGROUND: Chiropractic spinal manipulation has been reported to be of benefit
in nonmusculoskeletal conditions, including asthma. METHODS: We conducted a
randomized, controlled trial of chiropractic spinal manipulation for children
with mild or moderate asthma. After a three-week base-line evaluation period, 91
children who had continuing symptoms of asthma despite usual medical therapy were
randomly assigned to receive either active or simulated chiropractic manipulation
for four months. None had previously received chiropractic care. Each subject was
treated by 1 of 11 participating chiropractors, selected by the family according
to location. The primary outcome measure was the change from base line in the
peak expiratory flow, measured in the morning, before the use of a
bronchodilator, at two and four months. Except for the treating chiropractor and
one investigator (who was not involved in assessing outcomes), all participants
remained fully blinded to treatment assignment throughout the study. RESULTS:
Eighty children (38 in the active-treatment group and 42 in the simulated
treatment group) had outcome data that could be evaluated. There were small
increases (7 to 12 liters per minute) in peak expiratory flow in the morning and
the evening in both treatment groups, with no significant differences between the
groups in the degree of change from base line (morning peak expiratory flow,
P=0.49 at two months and P=0.82 at four months). Symptoms of asthma and use of 3
agonists decreased and the quality of life increased in both groups, with no
significant differences between the groups. There were no significant changes in
spirometric measurements or airway responsiveness. CONCLUSIONS: In children with
mild or moderate asthma, the addition of chiropractic spinal manipulation to
usual medical care provided no benefit.
PMID- 9761803
TI - A comparison of physical therapy, chiropractic manipulation, and provision of an
educational booklet for the treatment of patients with low back pain.
AB - BACKGROUND AND METHODS: There are few data on the relative effectiveness and
costs of treatments for low back pain. We randomly assigned 321 adults with low
back pain that persisted for seven days after a primary care visit to the
McKenzie method of physical therapy, chiropractic manipulation, or a minimal
intervention (provision of an educational booklet). Patients with sciatica were
excluded. Physical therapy or chiropractic manipulation was provided for one
month (the number of visits was determined by the practitioner but was limited to
a maximum of nine); patients were followed for a total of two years. The
bothersomeness of symptoms was measured on an 11-point scale, and the level of
dysfunction was measured on the 24-point Roland Disability Scale. RESULTS: After
adjustment for base-line differences, the chiropractic group had less severe
symptoms than the booklet group at four weeks (P=0.02), and there was a trend
toward less severe symptoms in the physical therapy group (P=0.06). However,
these differences were small and not significant after transformations of the
data to adjust for their non-normal distribution. Differences in the extent of
dysfunction among the groups were small and approached significance only at one
year, with greater dysfunction in the booklet group than in the other two groups
(P=0.05). For all outcomes, there were no significant differences between the
physical-therapy and chiropractic groups and no significant differences among the
groups in the numbers of days of reduced activity or missed work or in
recurrences of back pain. About 75 percent of the subjects in the therapy groups
rated their care as very good or excellent, as compared with about 30 percent of
the subjects in the booklet group (P<0.001). Over a two-year period, the mean
costs of care were $437 for the physical-therapy group, $429 for the chiropractic
group, and $153 for the booklet group. CONCLUSIONS: For patients with low back
pain, the McKenzie method of physical therapy and chiropractic manipulation had
similar effects and costs, and patients receiving these treatments had only
marginally better outcomes than those receiving the minimal intervention of an
educational booklet. Whether the limited benefits of these treatments are worth
the additional costs is open to question.
PMID- 9761804
TI - Effect of nebulized ipratropium on the hospitalization rates of children with
asthma.
AB - BACKGROUND: Anticholinergic medications such as ipratropium improve the pulmonary
function of patients with acute exacerbations of asthma, but their effect on
hospitalization rates is uncertain. METHODS: We conducted a randomized, double
blind, placebo-controlled study of 434 children (2 to 18 years old) who had acute
exacerbations of moderate or severe asthma treated in the emergency department.
All the children received a nebulized solution of albuterol (2.5 or 5 mg per
dose, depending on body weight) every 20 minutes for three doses and then as
needed. A corticosteroid (2 mg of prednisone or prednisolone per kilogram of body
weight) was given orally with the second dose of albuterol. Children in the
treatment group received 500 microg (2.5 ml) of ipratropium bromide with the
second and third doses of albuterol; children in the control group received 2.5
ml of normal saline at these times. RESULTS: Overall, the rate of hospitalization
was lower in the ipratropium group (59 of 215 children [27.4 percent]) than in
the control group (80 of 219 [36.5 percent], P=0.05). For patients with moderate
asthma (indicated by a peak expiratory flow rate of 50 to 70 percent of the
predicted value or an asthma score of 8 to 11 on a 15-point scale),
hospitalization rates were similar in the two groups (ipratropium: 8 of 79
children [10.1 percent]; control: 9 of 84 [10.7 percent]). For patients with
severe asthma (defined as a peak expiratory flow rate of <50 percent of the
predicted value or an asthma score of 12 to 15), the addition of ipratropium
significantly reduced the need for hospitalization (51 of 136 children [37.5
percent], as compared with 71 of 135 [52.6 percent] in the control group;
P=0.02). CONCLUSIONS: Among children with a severe exacerbation of asthma, the
addition of ipratropium bromide to albuterol and corticosteroid therapy
significantly decreases the hospitalization rate.
PMID- 9761805
TI - Bilateral orchiectomy with or without flutamide for metastatic prostate cancer.
AB - BACKGROUND: Combined androgen blockade for the treatment of metastatic prostate
cancer consists of an antiandrogen drug plus castration. In a previous trial, we
found that adding the antiandrogen flutamide to leuprolide acetate (a synthetic
gonadotropin-releasing hormone that results in medical ablation of testicular
function) significantly improved survival as compared with that achieved with
placebo plus leuprolide acetate. In the current trial, we compared flutamide plus
bilateral orchiectomy with placebo plus orchiectomy. METHODS: We randomly
assigned patients who had never received antiandrogen therapy and who had distant
metastases from adenocarcinoma of the prostate to treatment with bilateral
orchiectomy and either flutamide or placebo. Patients were stratified according
to the extent of disease and according to performance status. RESULTS: Of the
1387 patients who were enrolled in the trial, 700 were randomly assigned to the
flutamide group and 687 to the placebo group. Overall, the incidence of toxic
effects was minimal; the only notable differences between the groups were the
greater rates of diarrhea and anemia with flutamide. There was no significant
difference between the two groups in overall survival (P=0.14). The estimated
risk of death (hazard ratio) for flutamide as compared with placebo was 0.91 (90
percent confidence interval, 0.81 to 1.01). Flutamide was not associated with
enhanced benefit in patients with minimal disease. CONCLUSIONS: The addition of
flutamide to bilateral orchiectomy does not result in a clinically meaningful
improvement in survival among patients with metastatic prostate cancer.
PMID- 9761806
TI - Images in clinical medicine. Curschmann's spirals.
PMID- 9761807
TI - Parkinson's disease. First of two parts.
PMID- 9761808
TI - Care of patients undergoing hemodialysis.
PMID- 9761809
TI - Case records of the Massachusetts General Hospital. Weekly clinicopathological
exercises. Normal reference laboratory values.
PMID- 9761810
TI - What role for chiropractic in health care?
PMID- 9761812
TI - Correction: Outcomes in Patients with Acute Non-Q-Wave Myocardial Infarction
Randomly Assigned to an Invasive as Compared with a Conservative Management
Strategy.
PMID- 9761811
TI - Direct visualization of antigen-specific cytotoxic T cells--a new insight into
immune defenses.
PMID- 9761813
TI - Comparative studies of protein crystallization by vapour-diffusion and microbatch
techniques.
AB - Numerous reports have been published in the literature which describe the
crystallization of macromolecules by a variety of crystallization methods,
including the vapour-diffusion and microbatch techniques. This topical review
compares the results of examples of proteins which were crystallized by both
vapour-diffusion and microbatch methods. The inherent features of the vapour
diffusion and microbatch methods are discussed and some specific conditions where
one method appears more favourable than the other are reported. Guidelines for
the conversion of crystallization conditions from vapour diffusion to microbatch
(and vice versa) are also presented.
PMID- 9761814
TI - Water molecules hydrogen bonding to aromatic acceptors of amino acids: the
structure of Tyr-Tyr-Phe dihydrate and a crystallographic database study on
peptides.
AB - The crystal structure of Tyr-Tyr-Phe dihydrate contains a hydrogen bond formed
between a water molecule and the Phe side chain. The geometry is centered with a
distance of 3.26 A between the water O atom and the aromatic centroid. In a
database study on hydrated peptides, four related examples are found which
exhibit a wide variability of hydrogen-bond geometries. The intermolecular
surroundings of the water molecules are inspected, showing that they are
typically involved in complex networks of conventional and non-conventional
hydrogen bonds. Possible relevance for protein hydration is given.
PMID- 9761815
TI - Structure and proposed amino-acid sequence of a pepsin from atlantic cod (Gadus
morhua).
AB - The crystal structure of a pepsin from the gastric mucosa of Atlantic cod has
been determined to 2.16 A resolution. Data were collected on orthorhombic
crystals with cell dimensions a = 35.98, b = 75.40 and c = 108.10 A, on a FAST
area-detector system. The phase problem was solved by the molecular-replacement
method using porcine pepsin (PDB entry 5PEP) as a search model. The structure has
been refined to a crystallographic R factor of 20.8% using all reflections
between 8.0 and 2.16 A, without prior knowledge of the primary sequence. The
resulting crystal structure is very similar to the porcine enzyme, consisting of
two domains with predominantly beta-sheet structure in the same sequential
positions as the enzyme from pig. In the course of the model building, 122
residues were substituted and two residues deleted from the starting model to
give a polypeptide chain of 324 amino acids and a sequence identity of 57.7% with
the pig pepsin. No carbohydrate residues were located. Sequence alignment with
available aspartic proteinases, indicates that the fish enzyme seems to be more
related to mammalian gastric pepsins than to the mammalian gastricsins and
chymosins, lysosomal cathepsin D's and a pepsin from tuna fish. The amino-acid
composition of the cod enzyme, however, is more in accordance with the cathepsin
D's.
PMID- 9761816
TI - X-ray structure of the ZnII beta-lactamase from Bacteroides fragilis in an
orthorhombic crystal form.
AB - beta-Lactamases are extracellular or periplasmic bacterial enzymes which confer
resistance to beta-lactam antibiotics. On the basis of their catalytic
mechanisms, they can be divided into two major groups: active-site serine enzymes
(classes A, C and D) and the ZnII enzymes (class B). The first crystal structure
of a class B enzyme, the metallo-beta-lactamase from Bacillus cereus, has been
solved at 2.5 A resolution [Carfi, Pares, Duee, Galleni, Duez, Frere & Dideberg
(1995). EMBO J. 14, 4914-4921]. Recently, the crystal structure of the metallo
beta-lactamase from Bacteroides fragilis has been determined in a tetragonal
space group [Concha, Rasmussen, Bush & Herzberg (1996). Structure, 4, 823-836].
The structure of the metallo-beta-lactamase from B. fragilis in an orthorhombic
crystal form at 2.0 A resolution is reported here. The final crystallographic R
is 0.196 for all the 32501 observed reflections in the range 10-2.0 A. The
refined model includes 458 residues, 437 water molecules, four zinc and two
sodium ions. These structures are discussed with reference to Zn binding and
activity. A catalytic mechanism is proposed which is coherent with metallo-beta
lactamases being active with either one Zn ion (as in Aeromonas hydrophila) or
two Zn ions (as in B. fragilis) bound to the protein.
PMID- 9761817
TI - Accelerated X-ray structure elucidation of a 36 kDa muramidase/transglycosylase
using wARP.
AB - The X-ray structure of the 36 kDa soluble lytic transglycosylase from Escherichia
coli has been determined starting with the multiple isomorphous replacement
method with inclusion of anomalous scattering at 2.7 A resolution. Subsequently,
before any model building was carried out, phases were extended to 1.7 A
resolution with the weighted automated refinement procedure wARP, which gave a
dramatic improvement in the phases. The electron-density maps from wARP were of
outstanding quality for both the main chain and the side chains of the protein,
which allowed the time spent on the tracing, interpretation and building of the X
ray structure to be substantially shortened. The structure of the soluble lytic
transglycosylase was refined at 1.7 A resolution with X-PLOR to a final
crystallographic R factor of 18.9%. Analysis of the wARP procedure revealed that
the use of the maximum-likelihood refinement in wARP gave much better phases than
least-squares refinement, provided that the ratio of reflections to protein atom
parameters was approximately 1.8 or higher. Furthermore, setting aside 5% of the
data for an Rfree test set had a negative effect on the phase improvement. The
mean WwARP, a weight determined at the end of the wARP procedure and based on the
variance of structure factors from six individually refined wARP models, proved
to be a better indicator than the Rfree factor to judge different phase
improvement protocols. The elongated Slt35 structure has three domains named the
alpha, beta and core domains. The alpha domain contains mainly alpha-helices,
while the beta domain consists of a five-stranded antiparallel beta-sheet flanked
by a short alpha-helix. Sandwiched between the alpha and beta domains is the core
domain, which bears some resemblance to the fold of the catalytic domain of the
previously elucidated 70 kDa soluble lytic transglycosylase from E. coli. The
putative active site is at the bottom of a large deep groove in the core domain.
PMID- 9761818
TI - Melting points of lysozyme and ribonuclease A crystals correlated with protein
unfolding: a Raman spectroscopic study.
AB - The effects of a temperature increase on monoclinic and tetragonal lysozyme
single crystals were investigated by polarizing microscopy, X-ray diffraction and
laser Raman spectroscopy. To prevent dissolution, the mother liquor was removed,
and the crystals were covered by the oil poly-(chlorotrifluoroethylene). Upon
heating, their macroscopic shape was stable beyond 453 K but a change (or loss)
of birefringence was observed around 352 and 367 K for the tetragonal and
monoclinic crystal forms, respectively, which is associated with tighter packing
and higher crystal forces in monoclinic lysozyme. Raman spectral changes in the
amide I and amide III regions indicated denaturation of the protein within the
crystalline environment at temperature where birefringence changes, and
differences in the S-S band suggest that in monoclinic lysozyme, denaturation is
accompanied with disruption of some S-S bonds. Comparison with thermal
denaturation and gel formation (beta-aggregation) of lysozyme in solution
indicates that intermolecular interactions are mainly involved in the
stabilization of the denatured lysozyme crystals. The behavior of ribonuclease A
is very different. This protein unfolds and refolds reversibly in solution and
its crystals melt at the unfolding temperature at 333 K, i.e. loss of structure
induces breakdown of crystal lattice and macroscopic shape. Although the crystal
lattice of proteins is stabilized by only few intermolecular contacts, its
breakdown with increasing temperature is primarily a result of thermal unfolding
of the polypeptide chains.
PMID- 9761819
TI - A comparison of two algorithms for electron-density map improvement by
introduction of atomicity: skeletonization, and map sorting followed by
refinement.
AB - A comparison has been made of two methods for electron-density map improvement by
the introduction of atomicity, namely the iterative skeletonization procedure of
the CCP4 program DM [Cowtan & Main (1993). Acta Cryst. D49, 148-157] and the
pseudo-atom introduction followed by the refinement protocol in the program suite
DEMON/ANGEL [Vellieux, Hunt, Roy & Read (1995). J. Appl. Cryst. 28, 347-351].
Tests carried out using the 3.0 A resolution electron density resulting from
iterative 12-fold non-crystallographic symmetry averaging and solvent flattening
for the Pseudomonas aeruginosa ornithine transcarbamoylase [Villeret, Tricot,
Stalon & Dideberg (1995). Proc. Natl Acad. Sci. USA, 92, 10762-10766] indicate
that pseudo-atom introduction followed by refinement performs much better than
iterative skeletonization: with the former method, a phase improvement of 15.3
degrees is obtained with respect to the initial density modification phases. With
iterative skeletonization a phase degradation of 0.4 degrees is obtained.
Consequently, the electron-density maps obtained using pseudo-atom phases or
pseudo-atom phases combined with density-modification phases are much easier to
interpret. These tests also show that for ornithine transcarbamoylase, where 12
fold non-crystallographic symmetry is present in the P1 crystals, G-function
coupling leads to the simultaneous decrease of the conventional R factor and of
the free R factor, a phenomenon which is not observed when non-crystallographic
symmetry is absent from the crystal. The method is far less effective in such a
case, and the results obtained suggest that the map sorting followed by
refinement stage should be by-passed to obtain interpretable electron-density
distributions.
PMID- 9761820
TI - Crystallization and structure solution of p53 (residues 326-356) by molecular
replacement using an NMR model as template.
AB - The molecular replacement method is a powerful technique for crystal structure
solution but the use of NMR structures as templates often causes problems. In
this work the NMR structure of the p53 tetramerization domain has been used to
solve the crystal structure by molecular replacement. Since the rotation- and
translation-functions were not sufficiently clear, additional information about
the symmetry of the crystal and the protein complex was used to identify correct
solutions. The three-dimensional structure of residues 326-356 was subsequently
refined to a final R factor of 19.1% at 1.5 A resolution.
PMID- 9761821
TI - Crystallization and preliminary structural studies of Scilla campanulata lectin
complexed with alpha1-6 mannobiose.
AB - Recent work has shown that Scilla campanulata agglutinin from bluebell bulbs has
a strong affinity for alpha(1,3)- and alpha(1,6)-linked mannosyl residues and
possesses moderate antiretroviral activity. This lectin has been crystallized by
the hanging-drop method of vapour diffusion complexed with the disaccharide
mannose-alpha1,6-D-mannose. The crystals are in the space group P21212 with unit
cell dimensions a = 70.63, b = 92.79 and c = 47.25 A, and with a dimer in the
asymmetric unit. The crystals diffract X-rays to beyond 1.5 A resolution at 277 K
and are stable in an X-ray beam. Data to 1.6 A resolution have been collected
using a MAR image-plate system at a synchrotron source and the structure of the
complex has been solved by the molecular replacement method.
PMID- 9761823
TI - Crystallization and preliminary X-ray analysis of the 12S form of
phosphofructokinase from Saccharomyces cerevisiae.
AB - The tetrameric 12S form of yeast phosphofructokinase, obtained by limited
proteolytic cleavage of the native enzyme, was crystallized under a variety of
conditions. The crystals have been characterized in the X-ray beam and are
suitable for crystallographic studies.
PMID- 9761822
TI - Expression, purification, crystallization and crystallographic characterization
of dimeric and monomeric human neutrophil gelatinase associated lipocalin (NGAL).
AB - Crystals of the monomeric and dimeric forms of human neutrophil gelatinase
associated lipocalin have been grown in hanging-drop vapor-diffusion trials using
PEG as a precipitating agent with recombinant protein expressed in a baculovirus
based system. Crystals of monomeric NGAL belong to the cubic space group P432
with lattice constants a = b = c = 126.6 A; crystals of dimeric NGAL belong to
the tetragonal space group P41212 (or its enantiomorph P43212) with lattice
constants a = b = 54.14 and c = 121.56 A. Isomorphous crystals of the NGAL dimer
can be grown in the presence of ligand: the tripeptide N-formyl-Met-Leu-Phe.
PMID- 9761824
TI - Crystallization and preliminary X-ray analysis of the Tet-repressor/operator
complex.
AB - Three crystal forms of the repressor protein TetR class D in complex with the
palindromic 17 bp operator sequence containing T overhangs on both sides were
obtained by hanging-drop vapor-diffusion methods using PEG 4000 and PEG
monomethylether 5000 as precipitants. Although the crystallization conditions
were very similar, up to three different crystal forms were observed in the same
drop. The space groups are monoclinic C2, P21 and hexagonal P6122. The asymmetric
units of the latter two crystal forms contain one repressor-operator complex. The
crystal structures of these forms were solved by molecular replacement using the
Tet-repressor molecule of the complex with tetracycline as a search model.
PMID- 9761825
TI - Crystallization and preliminary crystallographic study of a component of the
Escherichia coli tol system: TolB.
AB - TolB from Escherichia coli is part of the Tol system used by the group A colicins
to penetrate and kill cells. A TolB derivative tagged with six histidines was
overexpressed, purified by chelation on a nickel affinity column and crystallized
using the SAmBA software to define the optimal crystallization protocol. The
crystals belong to the monoclinic system, space group P21 with unit-cell
parameters a = 64.48, b = 41.06, c = 78.41 A, beta = 110.78 degrees. Frozen
crystals diffract to 1.9 A resolution. Screening for heavy-atom derivatives both
on the native TolB and various cysteine-substituted mutants is in progress. In
addition, a selenomethionine-substituted protein is being produced in order to
use the MAD method for structure determination.
PMID- 9761826
TI - Crystallization and preliminary X-ray analysis of tyrosine aminotransferase from
Trypanosoma cruzi epimastigotes.
AB - Tyrosine aminotransferase from Trypanosoma cruzi has been crystallized from PEG
4000 at pH 6.8. The crystals belong to the monoclinic space group P21 and have
lattice constants of a = 59.1, b = 103.0, c = 77.8 A, beta = 113.1 degrees for a
data set measured at 138 K. The presence of a non-crystallographic twofold axis
together with a Matthews parameter Vm of 2.5 A3 Da-1 indicates that the
asymmetric unit contains one dimeric molecule. The crystals diffract to at least
2.7 A and are stable in the X-ray beam in a shock-frozen state. Native data sets
have been collected at temperatures of 285 and 138 K using a Siemens X1000
detector on a rotating-anode generator.
PMID- 9761827
TI - Crystallization and preliminary X-ray analysis of human platelet profilin
complexed with an oligo proline peptide.
AB - Profilin is an actin-monomer binding protein that regulates the distribution and
dynamics of the actin cytoskeleton. Profilin binds poly-L-proline and proline
rich peptides in vitro and co-localizes with proline-rich proteins in focal
adhesions and at the site of actin tail assembly on the surface of intracellular
parasites such as Listeria monocytogenes. The crystallization of the complex
between human platelet profilin (HPP) and an L-proline decamer [(Pro)10] is
reported here. Diffraction from these crystals is consistent with the space group
P21212 with unit-cell constants a = 68.25, b = 97.64, c = 39.10 A. The crystals
contain two HPP molecules per asymmetric unit and diffract to 2.2 A.
PMID- 9761828
TI - Crystallization and preliminary X-ray studies of sialidase L from the leech
Macrobdella decora.
AB - Functional monomeric 83 kDa sialidase L, a NeuAcalpha2-->3Gal-specific sialidase
from Macrobdella leech, was expressed in Escherichia coli and readily
crystallized by a macroseeding technique. The crystal belongs to space group P1
with unit-cell parameters a = 46.4, b = 69.3, c = 72.5 A, alpha = 113.5, beta =
95.4 and gamma = 107.3 degrees. There is one molecule per unit cell, giving a Vm
= 2.4 A3 Da-1 and a solvent content of 40%. Native and mercury-derivative data
sets were collected to 2.0 A resolution. Threading and molecular-replacement
calculations confirmed the existence of a bacterial sialidase-like domain.
PMID- 9761829
TI - Crystallization of the catalytic domain of Clostridium cellulolyticum CeLF
cellulase in the presence of a newly synthesized cellulase inhibitor.
AB - The catalytic domain of the CeIF processive endocellulase, a family 48 glycosyl
hydrolase from Clostridium cellulolyticum has been crystallized in the presence
of a newly synthesized inhibitor (methyl 4-S-beta-cellobiosyl-4-thio-beta
cellobioside), by vapour diffusion, using PEG as a precipitant. The protein
crystallizes in the orthorhombic P212121 space group and diffracts to a
resolution of 2.0 A. The unit-cell parameters are a = 61.4, b = 84.5, c = 121.9
A.
PMID- 9761830
TI - Crystallization and preliminary crystallographic investigation of porcine
quinolinate phosphoribosyltransferase.
AB - Quinolinate phosphoribosyltransferase (QPRT), purified from hog liver, has been
crystallized using PEG 8000 as the precipitant. The crystals form long hexagonal
rods in the space group P6322 with cell dimensions a = b = 121.7, c = 94.5 A.
Based on the unit-cell dimensions and the calculated molecular mass of 33 500 Da,
the Matthews coefficient suggests one molecule per asymmetric unit (Vm = 3.45 A3
Da-1; 64% solvent). Three native data sets were collected to a resolution of 2.5
A and merged to provide a set that is 94.7% complete, with an Rsym value of 9.6%.
PMID- 9761831
TI - Crystallization and preliminary X-ray crystallographic analysis of the helicase
domain of hepatitis C virus NS3 protein.
AB - The NS3 protein of hepatitis C virus (HCV) is thought to be essential for viral
replication. The N-terminal domain of the protein contains protease activity and
the C-terminal domain contains nucleotide triphosphatase and RNA helicase
activity. The RNA helicase domain of HCV NS3 protein was purified by using
affinity-column chromatographic methods, and crystallized by using the microbatch
crystallization method under oil at 277 K. The crystals belong to primitive
trigonal space group P3121 or P3221 with cell dimensions of a = b = 93.3, c =
104.6 A. The asymmetric unit contains one molecule of the helicase domain, with
the crystal volume per protein mass (Vm) of 2.50 A3 Da-1 and solvent content of
about 50.8% by volume. A native data set to 2.3 A resolution was obtained from a
frozen crystal indicating that the crystals are quite suitable for structure
determination by multiple isomorphous replacement.
PMID- 9761832
TI - Crystallization of Arthrobacter sp. strain 1C N-(1-D-carboxyethyl)-L-norvaline
dehydrogenase and its complex with NAD+
AB - The novel NAD+-linked opine dehydrogenase from a soil isolate Arthrobacter sp.
strain 1C belongs to an enzyme superfamily whose members exhibit quite diverse
substrate specificites. Crystals of this opine dehydrogenase, obtained in the
presence or absence of co-factor and substrates, have been shown to diffract to
beyond 1.8 A resolution. X-ray precession photographs have established that the
crystals belong to space group P21212, with cell parameters a = 104.9, b = 80.0,
c = 45.5 A and a single subunit in the asymmetric unit. The elucidation of the
three-dimensional structure of this enzyme will provide a structural framework
for this novel class of dehydrogenases to enable a comparison to be made with
other enzyme families and also as the basis for mutagenesis experiments directed
towards the production of natural and synthetic opine-type compounds containing
two chiral centres.
PMID- 9761833
TI - Crystallization and preliminary X-ray diffraction studies of bleomycin-binding
protein from bleomycin-producing Streptomyces verticillus.
AB - A bleomycin-binding protein (BLMA) produced by bleomycin-producing Streptomyces
verticullus was crystallized in a form suitable for X-ray diffraction analysis
using the vapor-diffusion method. Crystals were grown at pH 5.7, in 0.2 M NH4
actate and 0.1 M Na acetate, using 30% PEG 4000 as a precipitant. They belong to
the orthorhombic system, with space group P21212, cell dimensions a = 54. 90, b =
67.94, c = 35.60 A, and one BLMA molecule in the asymmetric unit. The crystals
diffract X-rays well and the diffraction intensity data was collected up to 1.5 A
resolution with a merging R value of 0.054 at beamline 6B of the Photon Factory.
The diffraction data set is 94% complete.
PMID- 9761834
TI - Crystallization and preliminary X-ray diffraction studies of a family 26 endo
beta-1,4 mannanase (ManA) from Pseudomonas fluorescens subspecies cellulosa.
AB - Crystals of an endo-beta-1,4-mannanase (1,4-beta-D-mannohydrolase, E. C.
3.2.1.78) from Pseudomonas fluorescens sub species cellulosa have been grown by
the hanging-drop technique at 291 K over a period of one to two weeks to maximal
dimensions of 0.17 x 0.17 x 0.25 mm. These crystals belong to the space group R32
(or R3) with cell dimensions of a = b = 155.4 and c = 250.8 A (hexagonal setting)
and contain three (six) molecules in the asymmetric unit. The crystals diffract
to at least 3.2 A using a laboratory source and are suitable for structure
determination.
PMID- 9761835
TI - Crystallization and preliminary X-ray analysis of the periplasmic receptor (PotF)
of the putrescine transport system in Escherichia coli.
AB - The primary receptor (PotF) of the putrescine transport system in E. coli has
been crystallized by the hanging-drop vapor-diffusion technique. The crystals
belong to the space group P21212 with unit-cell dimensions a = 269.4, b = 82.33
and c = 93.74 A. The crystals diffract beyond 2.2 A with a rotating-anode X-ray
source. A complete data set from the native crystals has been collected and
processed at 2.3 A resolution. Two heavy-atom derivatives have been prepared from
the same Pt compound at 293 and 277 K. The difference Patterson maps revealed
completely different major heavy-atom sites between these two derivatives.
PMID- 9761836
TI - The FNR-like domain of the Escherichia coli sulfite reductase flavoprotein
component: crystallization and preliminary X-ray analysis.
AB - The FNR-like domain of the Escherichia coli sulfite reductase flavoprotein
subunit was crystallized using the hanging-drop technique, with PEG 4000 as
precipitant. The crystals belong to space group P3112 or enantiomorph, with unit
cell parameters a = b = 171.0, c = 152.1 A. A solvent content of 75% was
determined by a calibrated tetrachloromethane/toluene gradient which corresponds
to three monomers per asymmetric unit. A 3 A resolution native data set was
collected at beamline W32 of LURE, Orsay, France.
PMID- 9761837
TI - Crystallization and preliminary crystallographic analyses of pokeweed antiviral
protein from seeds.
AB - Pokeweed antiviral protein from seeds (PAP-S) is a ribosome inactivating protein
which has lowest toxicity and highest inhibition activity as opposed to other
pokeweed antiviral proteins and its three potential glycosylation sites (10, 44,
255) were shown to bind to N-acetylglucosamine. Good quality crystals of PAP-S
were grown at high protein concentration (100 mg ml-1) and high temperature (306
K). The crystals have space group I222 and cell parameters a = 78.7, b = 85.2 and
c = 93.0 A. An X-ray diffraction data set with resolution up to 1.8 A was
collected. This high-resolution data will help to locate the sugars bound to the
protein and provide accurate structural data for understanding structure-function
relationships of PAP-S.
PMID- 9761838
TI - Crystallization of a complex between a novel C-terminal transmitter, HPt domain,
of the anaerobic sensor kinase ArcB and the chemotaxis response regulator CheY.
AB - The histidine-containing phosphotransfer (HPt) domain at the C-terminus of the
anaerobic sensor kinase ArcB has been cocrystallized with the chemotaxis response
regulator CheY by a hanging-drop vapor-diffusion method. Crystals belong to space
group P212121 with unit-cell dimensions a = 55.32, b = 76.29 and c = 83.89 A,
with one molecule in the crystallographic asymmetric unit. The crystals diffract
to 2.7 A resolution. This is the first crystallization of a protein-protein
complex formed by a transmitter domain of sensor kinase and a receiver domain of
response regulator in the two-component signal-transduction system.
PMID- 9761839
TI - Expression, purification and crystallization of the catalytic subunit of protein
kinase CK2 from Zea mays.
AB - The catalytic (alpha) subunit of protein kinase CK2 (CK2alpha) was originally
cloned and overexpressed in the Escherichia coli strain pT7-7/BL21(DE3). The
protein has been purified to homogeneity and crystallized. The crystals belong to
the monoclinic space group C2, they have unit-cell parameters a = 142.6, b =
61.3, c = 45.6 A, beta = 103.3 degrees and diffract X-rays to at least 2.0 A
resolution. The calculated crystal packing parameter is Vm = 2.47 A3 Da-1
suggesting that one CK2alpha molecule is contained in the asymmetric unit and
that the solvent content of the unit cell is 50%.
PMID- 9761840
TI - Crystals of bovine heart ubiquinol-cytochrome c reductase diffracting X-rays up
to 2.8 A resolution at 276 K.
AB - Bovine heart ubiquinol-cytochrome c reductase stabilized with sucrose monocaplate
was crystallized with polyethylene glycol as the precipitant at 277 K. X-rays
diffracted by the crystal were detected up to 2.8 A resolution at 266 K, without
using a synchrotron source. The space group and cell dimensions are P61 or P65
and a = b = 128.5 and c = 715.7 A, respectively.
PMID- 9761841
TI - Preliminary X-ray crystallographic studies of a newly defined human theta-class
glutathione transferase.
AB - Human theta-class glutathione S-transferases (GST's) appear to play a critical
role in the metabolism of a variety of environmental pollutants but in some cases
the products of the reaction are carcinogenic. Crystals of a human theta-class
GST, namely hGSTT2-2, have been grown from polyethylene glycol by the hanging
drop vapour-diffusion method. The crystals belong to the trigonal space group
P3121 with cell dimensions of a = b = 94.0 and c = 120.5 A. They contain two
monomers in the asymmetric unit and diffract to 3.0 A resolution.
PMID- 9761842
TI - Romit profile analysis for molecular replacements.
AB - A new procedure for evaluation of molecular replacement has been examined by
using an R factor calculated from the probe structure with some omitted parts
(Romit). It has been demonstrated that changes in Romit from the conventional R
factor for the whole structure are sensitive to the local fitness in the omitted
region even for large molecules such as proteins. Their profile, plotted against
residues, is effective for distinguishing the most probable one from several
solutions. In addition, this profile analysis exhibits useful information for
model building.
PMID- 9761843
TI - Structure of sulfur-substituted rhodanese at 1.36 A resolution.
AB - 1.36 A resolution X-ray diffraction data have been recorded at 100 K for bovine
liver sulfur-substituted rhodanese, using synchrotron radiation. The crystal
structure has been refined anisotropically to a final R factor of 0.159 (Rfree =
0.229) for 53034 unique reflections. The model contains 2327 protein atoms and
407 solvent molecules, with a good geometry. The high resolution allows full
details for helices, beta-sheets, tight turns and of all inter- and
intramolecular interactions stabilizing the enzyme molecule to be given. The
situation at the active site is described, particularly in regard to the network
of hydrogen bonds made by Sgamma and Sdelta of the sulfur-substituted catalytic
Cys247 and surrounding groups and solvent molecules. The replacement of the
precipitant ammonium sulfate with cryoprotectants in the crystal-suspending
medium led to the removal of the sulfate ion from the enzyme active site. Only
limited changes of the enzyme structure have been found as a result of the
drastic change in the crystal medium.
PMID- 9761844
TI - Miscellaneous algorithms for density modification.
AB - Various algorithms are described, developed for the dm density modification
package, which have not been described elsewhere. Methods are described for the
following problems: determination of the absolute scale and overall temperature
factor of a data set, by a method which is less dependent on data resolution than
Wilson statistics; an efficient interpolation algorithm for averaging and its
application to refinement of averaging operators; a method for the automatic
determination of averaging masks.
PMID- 9761846
TI - Structure of d(CACGCG).d(CGCGTG) in crystals grown in the presence of ruthenium
III hexammine chloride.
AB - Hexammine ions are strong inducers of the transition from the B-form to the left
handed Z-form in DNA. Here the structure of d(CACGCG). d(CGCGTG) obtained from
crystals grown from a drop containing [Ru(NH3)6]Cl3 is reported. The structure is
clearly characterized as Z-DNA. When compared with the structure of
d(CACGCG).d(CGCGTG)/MgCl2 and that of d(CGCGCG)2, subtle differences are seen,
most noticeably in the water structure. Since stable well diffracting crystals
grow easily in the presence of [Ru(NH3)6]Cl3 and since this ion is not visible in
the electron density it is concluded that the ion plays a non-specific role in
stabilizing Z-DNA.
PMID- 9761847
TI - Structure of a basic phospholipase A2 from Agkistrodon halys Pallas at 2.13 A
resolution.
AB - The basic phospholipase A2 isolated from the venom of Agkistrodon halys Pallas
(Agkistrodon blomhoffii Brevicaudus) is a hemolytic toxin and one of the few
PLA2's capable of hydrolyzing the phospholipids of E. coli membranes in the
presence of a bactericidal/permeability-increasing protein (BPI) of neutrophils.
The crystal structure has been determined and refined at 2.13 A to an R factor of
16.5% (F > 3sigma) with excellent stereochemistry. A superposition of the two
molecules in the asymmetric unit gives an r. m.s. deviation of 0.326 A for all
Calpha atoms. The refined structure allowed a detailed comparison with other PLA2
species of known structures. The overall architecture is similar to those of
other PLA2's with a few significant differences. One of which is in the region
connecting the N-terminal helix and the Ca2+-binding loop. Unexpectedly, the
conformation of the peptide plane Cys29-Gly30 in the Ca2+-binding loop is very
different to that of other PLA2's. The amide NH of Gly30 does not point toward
the proposed site for stabilization of the tetrahedral intermediate oxyanion of
the substrate analogue. The structure includes four residues which occur less
frequently in other PLA2's. His1, Arg6 and Trp70 located at the interfacial
recognition site may play an important role in the interaction with aggregated
substrates, while Trp77 contributes to the hydrophobic interactions between the
beta-wing and the main body of the molecule. This structure analysis reveals that
two clusters of basic residues are located at or near the interfacial recognition
site, forming an asymmetric positively charge distribution. In contrast to the
acidic isoform, the present enzyme is a dimer in the crystalline state. The
special phospholipid hydrolysis behaviors are discussed in the light of the
structure determined.
PMID- 9761848
TI - Refinement of triclinic hen egg-white lysozyme at atomic resolution.
AB - X-ray diffraction data have been collected at both low (120 K) and room
temperature from triclinic crystals of hen egg-white lysozyme to 0.925 and 0.950
A resolution, respectively, using synchrotron radiation. Data from one crystal
were sufficient for the low-temperature study, whereas three crystals were
required at room temperature. Refinement was carried out using the programs
PROLSQ, ARP and SHELXL to give final conventional R factors of 8.98 and 10.48%
for data with F > 4sigma(F) for the low- and room-temperature structures,
respectively. The estimated r.m.s. coordinate error is 0.032 A for protein atoms,
0.050 A for all atoms in the low-temperature study, and 0.038 A for protein atoms
and 0.049 A for all atoms in the room-temperature case, as estimated from
inversion of the blocked least-squares matrix. The low-temperature study revealed
that the side chains of 24 amino acids had multiple conformations. A total of 250
waters, six nitrate ions and three acetate ions, two of which were modelled with
alternate orientations were located in the electron-density maps. Three sections
of the main chain were modelled in alternate conformations. The room-temperature
study produced a model with multiple conformations for eight side chains and a
total of 139 water molecules, six nitrate but no acetate ions. The occupancies of
the water molecules were refined in both structures and this step was shown to be
meaningful when assessed by use of the free R factor. A detailed description and
comparison of the structures is made with reference to the previously reported
structure refined at 2.0 A resolution.
PMID- 9761849
TI - Rfree and the rfree ratio. I. Derivation of expected values of cross-validation
residuals used in macromolecular least-squares refinement.
AB - The last five years have seen a large increase in the use of cross validation in
the refinement of macromolecular structures using X-ray data. In this technique a
test set of reflections is set aside from the working set and the progress of the
refinement is monitored by the calculation of a free R factor which is based only
on the excluded reflections. This paper gives estimates for the ratio of the free
R factor to the R factor calculated from the working set for both unrestrained
and restrained refinement. It is assumed that both the X-ray and restraint
observations have been weighted correctly and that there is no correlation of
errors between the test and working sets. It is also shown that the least-squares
weights that minimize the variances of the refined parameters, also approximately
minimize the free R factor. The estimated free R-factor ratios are compared with
those reported for structures in the Protein Data Bank.
PMID- 9761850
TI - Structure of holo-glyceraldehyde-3-phosphate dehydrogenase from Palinurus
versicolor refined at 2 A resolution.
AB - The crystal structure of holo-glyceraldehyde-3-phosphate dehydrogenase from
Palinurus versicolor, South China sea lobster, was determined and refined at 2 A
resolution to an R factor of 17.1% and reasonable stereochemistry. The structure
refinement has not altered the overall structure of GAPDH from this lobster
species. However, some local changes in conformation and the inclusion of ordered
solvent model have resulted in a substantial improvement in the accuracy of the
structure. Structure analysis reveals that the two subunits including NAD+ in the
asymmetric unit are remarkably similar. The thermal differences between the two
subunits found in some regions of the NAD+-binding domain may originate from
different crystallographic environments rather than from an inherent molecular
asymmetry. In this structure, the side chain of Arg194 does not point toward the
active site but forms an ion pair with Asp293 from a neighboring subunit.
Structural comparisons with other GAPDH's of known structure reveal that obvious
contrast exists between mesophilic and thermophilic GAPDH mainly in the catalytic
domain with significant conformational differences in the S-loop, beta7-strand
and loop 120-125; the P-axis interface is more conserved than the R- and Q-axis
interfaces and the catalytic domain is more conserved than the NAD+-binding
domain. Some possible factors affecting the thermostability of this enzyme are
tentatively analyzed by comparison with the highly refined structures of
thermophilic enzymes.
PMID- 9761851
TI - 1.76 A structure of a pyrimidine start alternating A-RNA hexamer r(CGUAC)dG.
AB - The crystal structure of the alternating RNA r(CGUAC)dG with a 3'-terminal deoxy
G residue has been determined at 1.76 A resolution. The crystal belongs to the
orthorhombic space group C2221, unit-cell dimensions a = 29.53, b = 44.61 and c =
94.18 A, with two independent duplexes (I and II) per asymmetric unit. The
structure was solved by the molecular-replacement method. The final R factor was
18.8% using 4757 reflections in the resolution range 8.0-1.76 A. The model
contains a total of 496 atoms and 85 solvent molecules. The two duplexes form the
repeating unit and stack in the usual head-to-tail (5',3'/5',3') fashion into a
pseudocontinuous helical column. Almost all of the 2'-hydroxyl groups are engaged
in the three modes of water-mediated interactions to the base N3/O2 atoms, the
sugar O4' atoms and the backbone phosphates. Thus, the 2'-hydroxyl group of RNA
is probably contributing to the stability of the duplexes.
PMID- 9761852
TI - Structure of the DNA decamer d(GGCAATTGCG) contains both major- and minor-groove
binding G.(G.C) base triplets.
AB - The crystal structure of the decamer d(GGCAATTGCG) has been determined at 2.4 A
resolution. The central eight bases of each DNA single-strand base pair with a
self-complementary strand to form an octamer B-DNA duplex. These duplexes lie end
to-end within the unit cell. The terminal 5'-G and G-3' bases of each decamer
strand are unpaired, and interact with the neighbouring duplexes via interactions
within both the major and minor groove. This results in base triplets of the type
G-(G.C) and G*(G.C), with the third guanine base binding to a Watson-Crick G.C
base pair from the major groove and the minor groove, respectively. The triplet
interaction of the type G-(G.C) involves Hoogsteen hydrogen-bonding interactions
between the two guanine bases. The minor- and major-groove base triplet
interactions which exist within this structure act to stabilize the d(GCAATTGC)2
B-DNA octamer duplex.
PMID- 9761853
TI - Structural evidence for the aromatic-(i+1) amine hydrogen bond in peptides: L-tyr
L-tyr-L-Leu monohydrate.
AB - In crystalline Tyr-Tyr-Leu monohydrate, an aromatic-(i+1) amine hydrogen bond is
observed, that is a weak hydrogen-bond-type interaction between an aromatic side
chain and N-H of the next peptide group in the main chain. Unlike the better
investigated aromatic-(i+2) amine hydrogen bonds, which can adopt almost ideal
geometries, the geometry of the discussed interaction is very distorted because
of steric constraints. Presumably, this kind of weak hydrogen bond is only formed
as a last resort if N-H finds it impossible to engage in the much stronger
conventional hydrogen bonding with O-atom acceptors.
PMID- 9761854
TI - Structure of the Kunitz-type soybean trypsin inhibitor (STI): implication for the
interactions between members of the STI family and tissue-plasminogen activator.
AB - The Kunitz-type soybean trypsin inhibitor (STI) has played a key role in the
early study of proteinases, having been used as the main substrate in the
biochemical and kinetic work that led to the definition of the standard mechanism
of action of proteinase inhibitors. A partial structure of STI complexed with
porcine trypsin has previously been reported, in which the first 93 residues of
the inhibitor, including the region of contact with trypsin, were relatively well
defined, whereas for the remaining part of the peptide chain only some Calpha
atoms were located. The structure of the inhibitor in its free form has now been
determined by molecular replacement to 2.5 A, using the coordinates of the
homologous Erythrina trypsin inhibitor as a search model. When the refined atomic
coordinates of STI are compared with the partial model previously available, the
conformation of the reactive-site loop and its position with respect to the main
body of the molecule does not change when the inhibitor interacts with trypsin.
There are instead, despite the high similarity in the overall tertiary structure,
significant differences between STI and Erythrina trypsin inhibitor (ETI) in the
region which is in contact with the enzyme in the STI:trypsin crystal structure.
Some of these differences can explain the unique specificity of ETI and its
ability to inhibit the fibrinolytic enzyme tissue-type plasminogen activator.
PMID- 9761855
TI - Atomic resolution structure of human HBP/CAP37/azurocidin.
AB - Crystals of human heparin binding protein (HBP) diffract to 1.1 A when flash
frozen at 120 K. The atomic resolution structure has been refined anisotropically
using SHELXL96. The final model of HBP consists of 221 amino-acid residues of 225
possible, three glycosylation units, one chloride ion, 15 precipitant ethanol
molecules and 323 water molecules. The structure is refined to a final
crystallographic R factor of 15.9% and Rfree(5%) of 18.9% using all data. A
putative protein kinase C activation site has been identified, involving residues
113-120. The structure is compared to the previously determined 2.3 A resolution
structure of HBP.
PMID- 9761856
TI - On the choice of an optimal wavelength in macromolecular crystallography.
AB - Potential benefits of using short X-ray wavelengths for protein crystal data
collection arise from a reduction in absorption errors and a decrease in
radiation damage of a sample. On the other hand, at longer wavelengths one may
benefit from an increase in scattering efficiency of a crystal and an increase in
intensity of an incident beam at a given synchrotron beamline. For small and
frozen crystals the negative effects of absorption and radiation damage would be
minimized which may shift the balance of interests towards the use of longer
wavelengths. Experiments carried out at EMBL beamlines at DESY (Hamburg) show an
advantage of using wavelengths longer than 1 A for data collection from crystals
of up to 0.5 mm.
PMID- 9761857
TI - Direct phase determination in protein electron crystallography: aquaporin channel
forming integral membrane protein.
AB - The location of helix sites in the projected structure of the aquaporin channel
forming integral membrane protein from bovine red blood cells was determined by
multisolution direct methods to a mean accuracy of +/-1.9 A, based on hk0
electron diffraction data extending to 6 A. The structure was assumed to be
composed of pseudo-atoms, corresponding to the helix cross sections, and after re
scaling, normalized structure factors were used to order summation operatorn
triples according to the A values. Initial phases were found by symbolic addition
with algebraic unknowns. Probable solutions could be isolated by an overall
Luzzati test for density flatness and restrictions on local density extremes. The
best solution was identified by matching Patterson functions, generated from the
trial map density sites, to the one calculated from observed intensities.
PMID- 9761858
TI - Macromolecular crystal annealing: overcoming increased mosaicity associated with
cryocrystallography.
AB - Although cryogenic data collection has become the method of choice for
macromolecular crystallography, the flash-cooling step can dramatically increase
the mosaicity of some crystals. Macromolecular crystal annealing significantly
reduces the mosaicity of flash-cooled crystals without affecting molecular
structure. The process, which cycles a flash-cooled crystal to ambient
temperature and back to cryogenic temperature, is simple, quick and requires no
special equipment. The annealing process has been applied to crystals of several
different macromolecules grown from different precipitants and using a variety of
cryoprotectants. The protocol for macromolecular crystal annealing also has been
applied to restore diffraction from flash-cooled crystals that were mishandled
during transfer to or from cryogenic storage. These results will be discussed in
relation to crystal mosaicity and effects of radiation damage in flash-cooled
crystals.
PMID- 9761859
TI - Structure determination of a 16.8 kDa copper protein at 2.1 A resolution using
anomalous scattering data with direct methods.
AB - The structure of rusticyanin, an acid-stable copper protein, has been determined
at 2.1 A resolution by direct methods combined with the single-wavelength
anomalous scattering (SAS) of copper (f" = 3.9 e-) and then conventionally
refined (Rcryst = 18.7%, Rfree = 21.9%). This is the largest unknown protein
structure (Mr approximately /= 16.8 kDa) to be determined using the SAS and
direct-methods approach and demonstrates that by exploiting the anomalous signal
at a single wavelength, direct methods can be used to determine phases at typical
(approximately 2 A) macromolecular crystallographic resolutions. Extrapolating
from the size of the anomalous signal for copper (f" approximately 4 e-), this
result suggests that the approach could be used for proteins with molecular
weights of up to 33 kDa per Se (f"max++ = 8 e- at the 'white line') and 80 kDa
for a Pt derivative (f"max = 19 e- at the 'white line', L3 edge). The method
provides a powerful alternative in solving a de novo protein structure without
either preparing multiple crystals (i.e. isomorphous heavy-atom derivative plus
native crystals) or collecting multi-wavelength anomalous diffraction (MAD) data.
PMID- 9761860
TI - Crystallization and preliminary X-ray study of saporin, a ribosome-inactivating
protein from Saponaria officinalis.
AB - Single crystals of the protein saporin isolated from the seeds of S. officinalis
have been grown by the vapor-diffusion method using ammonium sulfate as
precipitant. The crystals are tetragonal, space group P4122 (P4322), with cell
dimensions a = b = 67.53 and c = 119. 67 A, and diffract to 2.0 A resolution on a
rotating-anode X-ray source. The asymmetric unit contains one molecule,
corresponding to a volume of the asymmetric unit per unit mass (Vm) of 2.38 A3 Da
1.
PMID- 9761861
TI - Purification, crystallization and preliminary X-ray diffraction studies of
retinal dehydrogenase type II.
AB - One enzyme which catalyzes the last step of the formation of the hormone retinoic
acid from vitamin A (retinol) is retinal dehydrogenase type II (Ra1DH2). Ra1DH2,
expressed in the Escherichia coli BL21(DE3) strain, was purified and crystallized
using ammonium sulfate as a precipitant. These crystals belong to the space group
P212121 (a = 108, b = 150, c = 168 A, alpha = beta = gamma = 90 degrees).
PMID- 9761863
TI - Purification, crystallization and preliminary X-ray analysis of the Escherichia
coli phytase.
AB - A recombinant form of Escherichia coli phytase, which hydrolyzes phytic acid into
phosphate and myo-inositol, has been expressed, purified and crystallized.
Crystals have been obtained by the method of bulk crystallization in 10 mM sodium
acetate buffer (pH 4.5) without using a conventional precipitant. The enzyme
crystallized in space group P21, with unit-cell dimensions a = 74.9, b = 72.2, c
= 82.4 A, and beta = 92.0 degrees. Crystals diffract to at least 2.2 A at a
rotating-anode X-ray source and a 2.3 A resolution data set has been collected,
giving completeness of 98.0% and an Rsym of 0.072. Assuming there are two phytase
molecules in the asymmetric unit, the solvent content is calculated to be 42.1%.
A self-rotation function shows a clear twofold non-crystallographic symmetry
relating two molecules of E. coli phytase in the asymmetric unit.
PMID- 9761862
TI - Crystallization of human complement component C5.
AB - Human complement component C5 has been crystallized using a low-salt batch
technique. The crystals are large hexagonal bi-pyramids often larger than 1.5 mm.
Although these crystals were grown in low salt (0.1 M NaCl), they are remarkably
stable for at least 2 months at 281 K and they are not dissolved in aqueous
buffers containing up to 2 M sodium chloride. The space group is P3121 or P3221,
and the cell parameters were determined to be a = 144.9, b = 144.9, c = 243.1 A;
alpha = 90 degrees, beta = 90, gamma = 120 degrees. At room temperature and cryo
temperatures the crystals diffract at best to 6 A using rotating-anode X-ray
sources. Using synchrotron radiation with cryoprotection using 40%(v/v) PEG 400
the resolution limit can be extended to 3.3 A. In both cases the crystals show
significant anisotropy, with relatively weaker reflections at higher resolution
in the a*b* plane.
PMID- 9761864
TI - Crystallization and preliminary X-ray crystallographic studies of the native and
chemically modified anion-selective porin from Comamonas acidovorans.
AB - Omp32, the strongly anion-selective porin from Comamonas acidovorans, has been
crystallized. Two crystal forms were observed, both of which belong to space
group R3, but exhibit different cell dimensions a = b = 106.7, c = 140.6 A
(crystal form I) and a = b = 87.1, c = 135.3 A (crystal form II) with one trimer
per asymmetric unit. The crystals diffract to 2.2 and 2.3 A resolution,
respectively. Omp32 was chemically modified by introducing negative charges
through succinylation. The number and positions of the individual modifications
were determined using mass spectrometry and X-ray crystallography. Chemically
modified porins yielded crystals of a third form, also of space group R3 but with
cell constants of a = b = 109.3 and c = 263.2 A (crystal form III), showing a
virtually doubled c axis. Crystals of form III diffract to 3.5 A resolution.
PMID- 9761865
TI - Crystallization and preliminary crystallographic studies of chloroplast NADP
dependent malate dehydrogenase from Flaveria bidentis.
AB - Crystals of chloroplast NADP-dependent malate dehydrogenase have been grown both
with and without the cofactor NADP present. The enzyme has a molecular weight of
43 kDa per subunit and exists as a dimer in solution. The crystals diffract to
2.8 A and belong to the space group P3221 with cell dimensions a = 148.1, c =
65.5 A.
PMID- 9761866
TI - Crystallization and preliminary X-ray analysis of IND, an enzyme with indole
oxygenase activity from Chromobacterium violaceum.
AB - IND, a redox flavoprotein from Chromobacterium violaceum has been crystallized in
the presence and absence of NADH. The crystals belong to the space group P41212
or its enantiomorph P43212 with a = 73.9 and c = 153.6 A. There is one molecule
per asymmetric unit and the crystals diffract beyond 2.1 A resolution.
PMID- 9761867
TI - Crystallization and preliminary X-ray diffraction analysis of aspartate
aminotransferase from Saccharomyces cerevisiae.
AB - Diffraction-quality crystals of S. cerevisiae cytoplasmic aspartate
aminotransferase have been obtained by the hanging-drop vapor-diffusion method in
the presence of pyridoxal phosphate and maleic acid, sodium acetate, ammonium
acetate and polyethylene glycol. The crystals have the symmetry of the
orthorhombic space groups P212121 or P21212 with unit-cell dimensions a = 130.2,
b = 134.6 and c = 98.7 A. Square rod-shaped crystals with dimensions of
approximately 0.2 x 0.2 x 0.5 mm diffract to spacings of 2 A. The calculated
value of the Matthews coefficient, Vm = 2.4 A3 Da-1, is consistent with four
subunits of aspartate aminotransferase per asymmetric unit.
PMID- 9761868
TI - Crystallization and preliminary X-ray studies of allophycocyanin from red alga
Porphyra yezoensis.
AB - Allophycocyanin from red alga Porphyra yezoensis has been crystallized in three
crystal forms. Form 1 crystals with space group P4132 or P4332 and cell
parameters a = 286 A, alpha = 90 degrees were obtained by using isopropanol as
precipitant. These crystals did not diffract beyond 5.8 A and could not be used
in structure analysis. Form 2 crystals were obtained when crystallization
conditions were slightly changed by adding 0.2 M magnesium chloride. The space
group of form 2 was not determined because it was difficult to get large single
crystals. Form 3 crystals were obtained by using ammonium sulfate as precipitant.
The space group of form 3 is R32 with cell dimensions a = b = 105.3, c = 189.4 A
and one alpha beta unit in the asymmetric unit. These crystals diffract up to
2.06 A resolution and are suitable for structure determination by molecular
replacement methods.
PMID- 9761869
TI - Scilla campanulata agglutinin crystallized in complex with the trimannoside alpha
D-man-(1-->6)-[alpha-D-man-(1-->3)]-alpha-D-Man.
AB - The monocot mannose-specific lectin, Scilla campanulata agglutinin (SCA), from
bluebell bulbs has a strong affinity for alpha1,3- and alpha1,6-linked mannosyl
residues. SCA has been co-crystallized with the trisaccharide alpha-D
mannopyranosyl-(1-->6)-alpha-D-mannopyranosyl-(1-->3)-alpha-D -mannopyranoside
?alpha-D-Man-(1-->6)-[alpha-D-Man-(1-->3)]-alpha-D-Man?, the core structure of
biantennary N-linked oligosaccharides. Crystals of the complex were obtained by
the hanging-drop vapour-diffusion technique. A complete data set to 2.5 A
resolution has been collected at 100 K, using a MAR image-plate system at a
synchrotron source, from crystals which belong to the space group C2 with unit
cell dimensions a = 99.38, b = 119.86, c = 77.10 A and beta = 105.56 degrees. Use
of a CCD detector with cryo-cooled crystals improved the resolution to 2.3 A. A
molecular replacement solution, with the 2.5 A data set, using the native SCA as
a search model was obtained, with six subunits per asymmetric unit.
PMID- 9761870
TI - Preliminary X-ray crystallographic study of wild-type and mutant ribulose-1,5
bisphosphate carboxylase/oxygenase from Chlamydomonas reinhardtii.
AB - Ribulose-1,5-bisphosphate carboxylase/oxygenase is the key enzyme for
photosynthesis. The wild-type and mutant (amino-acid substitutions in the
catalytically important loop 6 region) enzymes from Chlamydomonas reinhardtii, a
unicellular green alga, were crystallized. Wild-type, single-mutant (V331A) and
two double-mutant (V331A/T342I and V331A/G344S) proteins were activated with
cofactors CO2 and Mg2+, complexed with the substrate analog 2'-carboxyarabinitol
1,5-bisphosphate, and crystallized in apparently isomorphous forms. Unit-cell
determinations have been completed for three of the enzymes. They display
orthorhombic symmetry with similar cell parameters: wild type a = 130.4, b = 203.
3, c = 208.5 A; single mutant (V331A) a = 128.0, b = 203.0, c = 207. 0A; and
double mutant (V331A/T342I) a = 130.0, b = 202.1, c = 209.7 A. Crystals of the
wild-type and single-mutant (V331A) enzymes diffracted to approximately 2.8 A. A
small crystal of the double-mutant (V331A/T342I) enzyme diffracted to
approximately 6 A. A partial data set (68% complete) of the wild-type protein has
been collected at room temperature to about 3.5 A.
PMID- 9761871
TI - Characterization, crystallization and preliminary X-ray investigation of
glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic archaeon
Sulfolobus solfataricus.
AB - Recombinant Sulfolobus solfataricus glyceraldehyde-3-phosphate dehydrogenase has
been purified and found to be a tetramer of 148 kDa. The enzyme shows dual
cofactor specificity and uses NADP+ in preference to NAD+. The sequence has been
compared with other GAPDH proteins including those from other archaeal sources.
The purified protein has been crystallized from ammonium sulfate to produce
crystals that diffract to 2.4 A with a space group of P43212 or P41212. A native
data set has been collected to 2.4 A using synchrotron radiation and cryocooling.
PMID- 9761872
TI - Crystallization and preliminary diffraction studies of pentaerythritol
tetranitrate reductase from Enterobacter cloacae PB2.
AB - Pentaerythritol tetranitrate (PETN) reductase of Enterobacter cloacae PB2, a
flavoprotein involved in the biodegradation of the explosive PETN, ethylene
glycol dinitrate (EGDN) and glycerol trinitrate (GTN), was purified from an
overexpressing strain of E. coli and crystallized at 293 K using the sitting-drop
vapour-diffusion method. Diffraction data can be seen at 1.8 A. The primitive
orthorhombic cell has a monomer in the asymmetric unit. Preliminary molecular
replacement calculations have been performed using a search model based on Old
Yellow enzyme.
PMID- 9761873
TI - Crystallization of 5-keto-4-deoxyuronate isomerase from Escherichia coli.
AB - 5-Keto-4-deoxyuronate isomerase from Escherichia coli has been crystallized after
partial purification. The isomerase was found to be enriched in preparations of
an unrelated recombinant protein. Crystals of the isomerase were obtained from
two different precipitants despite the fact that the recombinant protein
represented roughly 90% of the total protein present. The crystals diffract to
2.7 A resolution and are suitable for a structure determination. The role of the
isomerase in E. coli is uncertain, as E. coli is not known to degrade the
polysaccharides which are potential sources of 5-keto-4-deoxyuronate.
PMID- 9761874
TI - Crystallization and preliminary X-ray studies of Pseudomonas putida histidine
ammonium-lyase.
AB - Histidine ammonium-lyase from P. putida was expressed in Escherichia coli,
purified to homogeneity, and crystallized by the vapour-diffusion method using
polyethylene glycol 3350 as the precipitant. The crystals, which diffract to at
least 2.5 A resolution, exhibit the symmetry of space group P212121, with unit
cell parameters a = 89.7, b = 138.2 and c = 164.8 A. The asymmetric unit contains
a tetramer, and the crystals have a Vm value of 2.41 A3 Da-1.
PMID- 9761876
TI - Crystallization and preliminary X-ray analysis of beta-glucan exohydrolase
isoenzyme ExoI from barley (Hordeum vulgare).
AB - Crystals of a beta-glucan exohydrolase purified from extracts of young barley
seedlings have been obtained by vapour diffusion in the presence of ammonium
sulfate and polyethylene glycol. The enzyme exhibits broad substrate specificity
against (1,3)-, (1,3;1,4)- and (1,3;1,6)-beta-glucans, and related
oligosaccharides. Crystal dimensions of up to 0.8 x 0.4 x 0.6 mm have been
observed. The crystals belong to the tetragonal space group P41212 or P43212.
Cell parameters are a = b = 102.1 and c = 184.5 A, and there appear to be eight
molecules in the asymmetric unit. The crystals diffract to at least 2.2 A
resolution using X-rays from a rotating-anode generator.
PMID- 9761875
TI - Preliminary crystallographic investigations of recombinant GDP-4-keto-6-deoxy-D
mannose epimerase/reductase from E. coli.
AB - The GDP-4-keto-6-deoxy-D-mannose epimerase/reductase (GM_ER) isolated from E.
coli has been overexpressed as a GST-fusion protein and purified to homogeneity.
The enzyme, an NADP+(H)-binding homodimer of 70 kDa, is responsible for the
production of GDP-L-fucose. GM_ER shows significant structural homology to the
human erythrocyte protein FX, which is involved in blood-group glycoconjugate
biosynthesis, displaying 3,5 epimerase/reductase activity on GDP-4-keto-6-deoxy-D
mannose. GM_ER has been crystallized in a trigonal crystalline form, containing
one molecule per asymmetric unit, suitable for high-resolution crystallographic
investigations.
PMID- 9761877
TI - Subcloning, crystallization and preliminary X-ray analysis of the signal receiver
domain of ETR1, an ethylene receptor from Arabidopsis thaliana.
AB - The signal receiver domain of ETR1, an ethylene receptor from Arabidopsis
thaliana, has been subcloned and expressed in E. coli and purified by affinity
chromatography. Crystals of both native and a selenomethionine-substituted form
of the receiver domain have been obtained. Native crystals grew in 1.6 M Li2SO4
and 0.1 M HEPES pH 7. 5 and once flash-frozen diffract to 2.1 A resolution. They
belong to space group P41212 with unit-cell dimensions a = b = 48.4, c = 112.3 A.
PMID- 9761878
TI - Preliminary X-ray analysis of a C2-like domain from protein kinase C-delta.
AB - C2 domains are intracellular modules of approximately 130 residues that are found
in many proteins involved in membrane trafficking and signal transduction. They
are known to serve a variety of roles including binding ligands such as calcium,
phospholipids and inositol polyphos-phates as well as interacting with larger
macromolecules. Although originally identified in the Ca2+-dependent protein
kinase C isoforms (PKC), initially no C2 domain was evident within the Ca2+
independent isoenzymes. A recent study identified a divergent C2 domain in
several novel, Ca2+-independent PKCs (delta, epsilon, eta and straight theta),
located at their N-termini in a region previously referred to as a variable
domain zero (Vo) [Ponting & Parker (1996). Protein Sci. 5, 2375-2390]. The
functional importance of this domain in the context of the novel PKCs is at
present not well understood though it has been implicated in substrate
recognition. The expression, crystallization and preliminary crystallographic
analysis of recombinant Vo domain (residues 1-123) from PKC-delta is reported
here. Crystals were obtained from incomplete factorial screens after removal of
the histidine tag used to aid purification. These crystals diffracted to Bragg
spacings of approximately 3 A using a rotating-anode source and to 1.9 A using
synchrotron radiation. The crystals have cell parameters of a = 60.7, b = 120.9
and c = 40.7 A and systematic absences consistent with the orthorhombic space
group P212121. To facilitate structure determination we have prepared,
characterized and crystallized selenomethionine-substituted material.
PMID- 9761879
TI - Crystallization and preliminary X-ray analysis of ferric enterobactin receptor
FepA, an integral membrane protein from Escherichia coli.
AB - Diffraction-quality crystals have been obtained of the integral membrane protein
ferric enterobactin receptor (FepA) from the outer membrane of Escherichia coli.
Crystals were grown using the zwitterionic detergent lauryldimethylamine oxide
(LDAO), the precipitants polyethylene glycol (PEG) 1000 and sodium chloride, and
the additive heptane-1,2,3-triol; they have the symmetry of the orthorhomic space
group C2221 with a = 112.2, b = 137.2 and c = 135. 4 A and diffract to 2.5 A
resolution. The crystals were flash-cooled and a preliminary data set was
collected at 103 K. The crystals are suitable for three-dimensional structure
analysis.
PMID- 9761880
TI - Structure of type III antifreeze protein at 277 K.
AB - Fish antifreeze proteins (AFP's) depress the freezing point of blood and other
body fluids below that of the surrounding seawater by binding to and inhibiting
the growth of seed ice crystals. The high-resolution crystal structure of type
III AFP, determined at room temperature, reveals a remarkably flat surface
containing most of the ice-binding residues [Jia et al. (1996). Nature (London),
384, 285-288]. Since AFP's function at temperatures close to 273 K, it is
important to know whether the structure determined at room temperature undergoes
any change at much lower temperature. Therefore, type III AFP has been
crystallized at 277 K and its structure determined. Although crystallization
conditions at 277 K were similar to those at approximately 295 K, crystal growth
took much longer at the lower temperature. Crystals grown at the two temperatures
were isomorphous. Initial crystals appeared within 40-50 d and grew to their
final size in about 8-12 months, instead of a couple of days at approximately 295
K. The type III antifreeze protein structure from crystals grown at 277 K was
essentially the same as that determined at approximately 295 K, with the
exception of some minor changes in side-chain conformation. The result is an
indication that temperature has a minimal effect on the structure of type III
AFP, thus lending increased physiological validity to the room-temperature
structure which was used for the initial ice-binding modelling.
PMID- 9761881
TI - Protein crystals orientation in a magnetic field.
AB - Nucleation and crystal growth of hen egg-white lysozyme, bovine pancreatic
trypsin inhibitor and porcine pancreatic alpha-amylase were carried out in the
presence of a magnetic field of 1.25 T produced by small permanent magnets.
Crystals were oriented in the magnetic field, except when heterogeneous
nucleation occurred. The orientation of protein crystals in the presence of a
magnetic field can be attributed to the anisotropic diamagnetic susceptibility of
proteins resulting from the large anisotropy of the alpha-helices due to the
axial alignment of the peptide bonds.
PMID- 9761882
TI - A general phasing algorithm for multiple MAD and MIR data.
AB - A phasing algorithm is presented for combining multiple wavelength anomalous
dispersion (MAD) data from multiple types of anomalous scatterers, either in the
same or in different derivative crystals, as well as for combining MAD data with
multiple isomorphous replacement (MIR) data from different derivative crystals. A
heavy-atom phasing and refinement program originally written by Rossmann [(1967)
HATOMLSQ program, Purdue University, West Lafayette, Indiana, USA] has been
modified to refine the parameters that define the anomalous and isomorphous
scatterers and to determine protein phases by using all MAD and MIR derivatives
simultaneously. The technique allows for appropriate weighting of every data set,
including the native data, which contains neither an anomalous nor an isomorphous
component. This method is a generalization of currently used heavy-atom methods.
Numerical tests are presented for different experimental scenarios, including a
double MAD experiment on the same crystal (diffraction data at two absorption
edges), combination of two MAD experiments on different crystals, and combination
of MAD data with MIR data from multiple crystals. An appendix shows how the Karle
equations used in MAD phasing can be reformulated as a particular case of this
algorithm.
PMID- 9761883
TI - Structure of balhimycin and its complex with solvent molecules.
AB - Balhimycin is a naturally occurring glycopeptide antibiotic, related to
vancomycin which acts by binding nascent bacterial cell-wall peptide ending in
the sequence D-Ala-D-Ala. Crystals of balhimycin are monoclinic, space group P21,
a = 20.48 (10), b = 43.93 (21), c = 27.76 (14) A, beta = 100.5 (5) degrees with
four independent antibiotic molecules, three molecules of 2-methyl-2,4
pentanediol, two citrate ions, three acetate ions and 127.5 water molecules in
the asymmetric unit. With an asymmetric unit larger than those of the smallest
proteins and a solvent content of about 32%, the crystals have similar
diffraction properties to those of small proteins. 27387 unique reflections were
collected using synchrotron radiation. The structure was solved by a standard
protein technique, the molecular-replacement method, using ureido-balhimycin as
search model. The anisotropic refinement against all F2 data between 0.96 and 45
A converged to a conventional R value of 11.27% with R1= Sigma||Fo|
|Fc||/Sigma|Fo| for the 24623 data with I > 2sigma(I) and 12.58% for all 27387
data. The four monomers possess fairly similar conformations (r.m.s. deviation
0.7 A). Two antibiotic molecules form a tight dimer with antiparallel hydrogen
bonds between the peptide backbone as well as between the vancosamine residues
and the peptide backbone. In each of the two dimers, one binding pocket is
occupied by a citrate ion and the other by an acetate ion. The dimer units are
linked in the crystal by hydrogen bonds to form infinite chains.
PMID- 9761884
TI - Data compression for diffraction patterns.
AB - Efficient coding (lossless) and compression (lossy) of diffraction patterns is
important in protein crystallography experiments because of storage and
transmission limitations. The goal is to reduce the bit-rate significantly while
keeping diffraction peak intensity distortion at an acceptable level. This paper
presents an overview of coding and compression techniques more or less adapted to
such problems. A large part of this study is dedicated to time-frequency
transform based compression algorithms and some of their extensions. Wavelet
based software has been developed and tested. Results are compared with the
discrete cosine transform (DCT) and other classical algorithms. These tools seem
attractive and very promising for analyzing and compressing signals with
singularities and transient phenomena such as diffraction peaks. Tests were
performed on a standard protein crystallography data set coming from the CCD
detector of D2AM beamline at the European Synchrotron Radiation Facility at
Grenoble. These were compressed with DCT and wavelet-based algorithms. It appears
that alterations of the result of the processing of restored images remain very
weak for compression rates up to 10. These preliminary results indicate that the
proposed wavelet method is a good standard technique for efficient compression of
diffraction patterns.
PMID- 9761885
TI - Stationary crystal diffraction with a monochromatic convergent X-ray source and
application for macromolecular crystal data collection.
AB - A diffraction geometry utilizing convergent X-rays from a polycapillary optic
incident on a stationary crystal is described. A mathematical simulation of the
resulting diffraction pattern (in terms of spot shape, position and intensity) is
presented along with preliminary experimental results recorded from a lysozyme
crystal. The effective source coverage factor is introduced to bring the
reflection intensities onto the same scale. The feasibility of its application to
macromolecular crystal data collection is discussed.
PMID- 9761886
TI - Low-resolution structural characterization of the arginine repressor/activator
from Bacillus subtilis: a combined X-ray crystallographic and electron
microscopical approach.
AB - Attempts to determine the X-ray crystal structure of the intact homohexameric
arginine repressor/activator from B. subtilis have so far been unsuccessful. The
major problem appears to be the lack of an isomorphous heavy-atom derivative with
a manageable number of substitution sites. Here it is shown how electron
microscopy of thin three-dimensional crystals, the same as those used for the X
ray crystallographic studies, made it possible (i) to obtain experimental support
for some conclusions drawn on the basis of X-ray data alone, (ii) to determine
the low-resolution distribution of electron density in several different
crystallographic projections, and (iii) to obtain a tentative low-resolution
model of the whole hexamer.
PMID- 9761887
TI - Effects of microheterogeneity in hen egg-white lysozyme crystallization.
AB - In earlier sodium dodecylsulfate-polyacylamide gel electrophoresis (SDS-PAGE)
studies it has been found that commonly utilized commercial hen egg-white
lysozyme (HEWL) preparations contained 0.2-0.4 mol% covalently bound dimers. Here
it is shown, using high-performance capillary electrophoresis (HPCE), that HEWL
contains, in addition, two differently charged monomers in comparable amounts. To
explore the origin of these microheterogeneous contaminants, purified HEWL
(PHEWL) has been oxidized with hydrogen peroxide (0.0026-0.88 M) at various pH
levels between 4.5 and 12.0. Optical densitometry of oxidized PHEWL (OHEWL) bands
in SDS-PAGE gels shows that hydrogen peroxide at 0.88 M in acetate buffer pH 4.5
increased the amount of dimers about sixfold over that in commercial HEWL. OHEWL
had, in addition to one of the two monomer forms found in HEWL and PHEWL, three
other differently charged monomer forms, each of them representing about 25% of
the preparation. SDS-PAGE analysis of OHEWL yielded two closely spaced dimer
bands with Mr = 28000 and 27500. In addition, larger HEWL oligomers with Mr = 1.7
million and 320000 were detected by gel-filtration fast protein liquid
chromatography with multiangle laser light scattering detection. Non-dissociating
PAGE in large pore size gels at pH 4.5 confirmed the presence of these large
oligomers in HEWL and OHEWL. Increased microheterogeneity resulted in substantial
effects on crystal growth and nucleation rate. On addition of 10 microgram-1 mg
ml-1 OHEWL to 32 mg ml-1 HEWL crystallizing solutions, both the number and size
of forming crystals decreased roughly proportionally to the concentration of the
added microheterogeneity. The same effect was observed in HEWL solutions on
addition of 0.03-0.3 M hydrogen peroxide. Repartitioning of the dimer during
crystallization at various temperatures between 277 and 293 K was analyzed by SDS
PAGE. The crystals contained = 25%(w/w) of the oligomers in the solution, with
no apparent temperature dependence of the repartitioning.
PMID- 9761889
TI - Error estimates of protein structure coordinates and deviations from standard
geometry by full-matrix refinement of gammaB- and betaB2-crystallin.
AB - Faster workstations with larger memories are making error estimation from full
matrix least-squares refinement a more practicable technique in protein
crystallography. Using minimum variance weighting, estimated standard deviations
of atomic positions have been calculated for two eye lens proteins from the
inverse of a least-squares normal matrix which was full with respect to the
coordinate parameters. gammaB-crystallin, refined at 1.49 A yielded average
errors in atomic positions which ranged from 0.05 A for main-chain atoms to 0.27
A for unrestrained water molecules. The second structure used in this work was
that of betaB2-crystallin refined at 2.1 A resolution where the corresponding
average errors were 0.08 and 0.35 A, respectively. The relative errors in atomic
positions are dependent on the number and kinds of restraints used in the
refinements. It is also shown that minimum variance weighting leads to mean
square deviations from target geometry in the refined structures which are
smaller than the variances used in the distance weighting.
PMID- 9761888
TI - Application of known triplet phases in the crystallographic study of bovine
pancreatic trypsin inhibitor. II: study at 2.0 A resolution.
AB - Direct methods strengthened by the application of about 130 triplet phases,
assumed known with a mean error of about +/- 20 degrees, were used to re
determine the structure of BPTI with data at 2.0 A resolution. The triplet phases
served to shift the mean direction and enhance the concentration parameter in the
corresponding Cochran distributions. These phases were used in combination with
the partial structure extracted from successive density maps to control the
gradual expansion and refinement of Fourier coefficients. Single phases were
developed iteratively from tangent-formula estimation following the path of the
convergence map. The a priori triplet phase information was sufficient to
initiate solution of the structure at 2.0 A.
PMID- 9761890
TI - Crystallographic study of azurin from Pseudomonas putida.
AB - Azurin from Pseudomonas putida is a blue copper protein which functions as an
electron carrier. Two crystal forms of azurin were grown, one in the presence and
the other in the absence of zinc acetate; each belongs to space group P21 and
contains two molecules per asymmetric unit. The zinc-free crystals have cell
dimensions a = 43.25, b = 50.65, c = 54.60 A, beta = 107.79 degrees, while the
crystals grown from zinc-containing solution have cell dimensions a = 40.76, b =
51.22, c = 54.96 A, beta = 103.12 degrees. The latter crystals were found to have
four zinc ions incorporated into the crystal lattice. Both crystal structures
were solved by the molecular-replacement method using the program MERLOT. The
search model was the structure of azurin from Alcaligenes denitrificans. The
crystallographic R factor for native azurin is 0.169 (Rfree = 0. 257) from 8 to
1.92 A resolution, while that for zinc azurin is 0. 181 (Rfree = 0.248) from 10
to 1.6 A resolution; for each structure the root-mean-square deviation in bond
lengths from ideal values is 0.007 A. In both crystal structures the Cu atom
forms three strong bonds in the equatorial plane, two with Ndelta1 from His46 and
His117, and one with the thiolate S atom of Cys112. Two longer axial approaches
are made by the Sgamma from Met121 and the carbonyl O atom from Gly45. This
results in a distorted trigonal bipyramidal co-ordination around the Cu atom. It
further confirms the presence of a weak fifth bond to the copper in P. putida
azurin, as with other azurin structures described at high resolution. The Ndelta1
atom of His35 is protonated, as it is in the low-pH form of azurin from
Pseudomonas aeruginosa but unlike the low-pH form of the azurins from Alcaligenes
denitrificans or Alcaligenes xylosoxidans. In each crystal form the two molecules
of azurin in the asymmetric unit are related by a local twofold axis and form a
dimer stabilized by the interaction of a pair of hydrophobic patches surrounding
the partially exposed His117 side chain. In the other known azurin crystal
structures, analogous dimer formation is observed, but with different relative
orientations of the molecules. The four zinc ions introduced during
crystallization of zinc azurin are bound to the protein and participate in five-
and sixfold ligand coordination with no affect on the copper binding site. The
zinc ligands are Ndelta from His, carboxylate O atoms from Asp and Glu, Ogamma
from Ser and water molecules. One of the zinc ions, located on a non
crystallographic twofold axis, links the dimers of the asymmetric unit into
continuous chains parallel to the crystallographic (-101) direction and is
primarily responsible for the altered unit-cell parameters. Two of the other zinc
ions bind to His83, one in each molecule.
PMID- 9761891
TI - Crystallization of NAD+-dependent phenylalanine dehydrogenase from Nocardia
sp239.
AB - The NAD+-dependent phenylalanine dehydrogenase from Nocardia sp239 has been
crystallized by the hanging-drop method of vapour diffusion using ammonium
sulfate as the precipitant. Two crystal forms were obtained in the presence and
absence of the enzyme substrates phenylpyruvic acid or phenylalanine and its
coenzyme NADH. Crystals of the native protein belong to the hexagonal system,
with the space group being one of the enantiomorphic pair P6122 or P6522. The
cell dimensions are a = b = 111.0, c = 174.5 A, alpha = beta = 90 and gamma = 120
degrees. Crystals grown from the protein co-crystallized with its substrates all
belong to the trigonal system, space group P3121 or P3221, with unit-cell
dimensions of a = b = 88.1, c = 112.6 A, alpha = beta = 90 and gamma = 120
degrees. Preliminary protein-sequencing experiments have established that this
enzyme is related to the octameric PheDH's which are members of the wider
superfamily of amino-acid dehydrogenases. However, gel-filtration studies suggest
that this enzyme is active as a monomer. The full determination of the three
dimensional structure of this phenylalanine dehydrogenase will add to the
understanding of the molecular basis of the differential substrate specificity
within this enzyme superfamily. In turn this will contribute to the rational
design of an amino-acid dehydrogenase which could be used for the diagnosis of
phenylketonuria and for the chiral synthesis of high-value pharmaceuticals.
PMID- 9761892
TI - Crystallization and preliminary X-ray analysis of tetanus neurotoxin C fragment.
AB - Two crystal forms of recombinant tetanus neurotoxin C fragment have been
obtained. The C fragment corresponds to the C-terminal 451 amino-acid residues of
tetanus neurotoxin and is the subunit responsible for receptor binding by the
toxin. Both forms belong to space group P212121. Form I has unit-cell dimensions
of a = 71.3, b = 79.7, c = 94.0 A and produces thin plate crystals. Form II has
unit-cell dimensions of a = 67.4, b = 79.7, c = 91.1 A and produces thick rod
shaped crystals. Diffraction data to 2.6 A have been collected from form II
crystals.
PMID- 9761893
TI - Crystallization of the alpha-hemolysin heptamer solubilized in decyldimethyl- and
decyldiethylphosphine oxide.
AB - Crystals of the alpha-hemolysin heptamer, a transmembrane pore-forming toxin from
Staphylococcus aureus, have been grown using the nonionic detergents n
decyldimethyl- and n-decyldiethylphosphine oxide, phosphorus homologs of the
ionic amine oxide detergents. Five crystal forms were obtained, one of which
diffracted X-rays to 3 A resolution. This crystal form displayed elements of
pseudo mm symmetry in screened precession photographs yet it was triclinic with
unit-cell dimensions a = 173, b = 173, c = 102 A, alpha = 92.6, beta = 94.8,
gamma = 90.2 degrees.
PMID- 9761894
TI - Crystallization and preliminary analysis of chondroitinase AC from Flavobacterium
heparinum.
AB - Chondroitinase AC (E.C. 4.2.2.5) overexpressed in its host, Flavobacterium
heparinum, was crystallized by vapor diffusion using polyethylene glycol methyl
ether as precipitant. It crystallizes in the space group P43212 or its
enantiomorph with a = b = 87.1 and c = 193.1 A and one molecule in the asymmetric
unit. Crystals diffract to a maximum of 2.5 A resolution on a rotating-anode
source. Screening for heavy-atom derivatives identified a lead compound that
binds to a single site on the protein. Further screening is in progress.
PMID- 9761895
TI - Crystallization and preliminary X-ray diffraction studies of phospho
adenylylsulfate (PAPS) reductase from E. coli.
AB - PAPS reductase from E. coli is involved in sulfur metabolism and catalyses the
reduction of phospho-adenylyl-sulfate (PAPS) to sulfite. The protein has been
cloned, overexpressed and purified from E. coli. Crystallization experiments
resulted in crystals suitable for X-ray diffraction. The crystals belong to the
orthorhombic space group C2221 with cell dimensions a = 81.9, b = 97.4, c = 109.5
A, and contain one molecule per asymmetric unit. At cryogenic (100 K)
temperatures the crystals diffract to a resolution limit of 2.7 A using a
rotating anode and to 2.0 A at a synchrotron source.
PMID- 9761896
TI - Crystallization and preliminary X-ray diffraction analysis of cytochrome c' from
Rubrivivax gelatinosus at 1.3 A resolution.
AB - Cytochrome c' from the purple non-sulfur phototrophic bacterium Rubrivivax
gelatinosus has been crystallized by vapour diffusion at pH 5, 6.3 and 8, in
sodium acetate, sodium citrate, and Tris-HCl buffers, respectively. Crystals
grown at pH 5 and 6.3 diffract, respectively, to 2.0 A (298 K) and 1.4 A (100 K)
using synchrotron radiation. Data up to 1.3 A resolution with 99.8% completeness
were collected at 100 K on a crystal grown at pH 8. The space group is P3121 or
P3221, and the unit-cell parameters are a = b = 69.63, c = 123.63 A.
PMID- 9761897
TI - 1.2 A refinement of the Kunitz-type domain from the alpha3 chain of human type VI
collagen.
AB - The recombinant Kunitz-type domain (C5) of human collagen alpha3(VI) chain was
previously described at 1.6 A resolution at room temperature. By changing the
crystallization conditions and using synchrotron radiation, we are able to record
diffraction data to 1.2 A resolution for crystals of the same space group at 291
K. The protein-water-ion model has been refined anisotropically against these new
data using the program SHELXL93; the results converged to an R factor of 15.0%,
with all data between 7 and 1.2 A. The final electron-density map reveals a clear
chain tracing with a few disordered residues and five residues out of 58 that
present alternate conformations. The Cys14-Cys38 bond presents the less
frequently observed left-hand conformation (chi1 = -60 degrees). The solvent
molecules and a phosphate ion are well ordered with an average B of 38 A2. The
high-resolution structure reveals the N and C termini which were missing from the
1.6 A structure.
PMID- 9761898
TI - 1.85 A resolution structure of the zinc (II) beta-lactamase from Bacillus cereus.
AB - Class B beta-lactamases are wide spectrum enzymes which require bivalent metal
ions for activity. The structure of the class B zinc-ion-dependent beta-lactamase
from Bacillus cereus (BCII) has been refined at 1.85 A resolution using data
collected on cryocooled crystals (100 K). The enzyme from B. cereus has a
molecular mass of 24 946 Da and is folded into a beta-sandwich structure with
helices on the external faces. The active site is located in a groove running
between the two beta-sheets [Carfi et al. (1995). EMBO J. 14, 4914-4921]. The 100
K high-resolution BCII structure shows one fully and one partially occupied zinc
sites. The zinc ion in the fully occupied site (the catalytic zinc) is
coordinated by three histidines and one water molecule. The second zinc ion is at
3.7 A from the first one and is coordinated by one histidine, one cysteine, one
aspartate and one unknown molecule (most likely a carbonate ion). In the B.
cereus zinc beta-lactamase the affinity for the second metal-ion is low at the pH
of crystallization (Kd = 25 mM, 293 K; [Baldwin et al. (1978). Biochem. J. 175,
441-447] and the dissociation constant of the second zinc ion was thus apparently
decreased at the cryogenic temperature. In addition, the structure of the apo
enzyme was determined at 2.5 A resolution. The removal of the zinc ion by
chelating agents causes small changes in the active-site environment.
PMID- 9761899
TI - Molecular replacement using DNA helical symmetry.
AB - The efficiency of molecular-replacement methods in the structure analysis of B
DNA is markedly increased if a knowledge of the structural properties and helical
symmetry of B-DNA is incorporated into molecular-replacement procedures. The
separation of the most significant or most robust parameters, such as the
location of helices in the unit cell, from the less well defined parameters, such
as rotation around the helix axis, further improves the reliability of molecular
replacement and avoids frameshift errors in the positioning of the model. This
approach has been applied successfully to solve novel structures of four B-DNA
decamers in various space groups.
PMID- 9761900
TI - Structure of the complex of bovine pancreatic phospholipase A2 with a transition
state analogue.
AB - The 1.89 A resolution structure of the complex of bovine pancreatic phospholipase
A2 (PLA2) with the transition-state analogue L-1-O-octyl-2-heptylphosphonyl-sn
glycero-3-phosphoethanolamine (TSA) has been determined. The crystal of the
complex is trigonal, space group P3121, a = b = 46.58 and c = 102.91 A and
isomorphous to the native recombinant wild type (WT). The structure was refined
to a final crystallographic R value of 18.0% including 957 protein atoms, 88
water molecules, one calcium ion and all 31 non-H atoms of the inhibitor at 1.89
A resolution. In all, 7 726 reflections [F>2sigma(F)] were used between 8.0 and
1.89 A resolution. The inhibitor is deeply locked into the active-site cleft and
coordinates to the calcium ion by displacing the two water molecules in the
calcium pentagonal bipyramid by the anionic O atoms of the phosphate and
phosphonate group. The hydroxyl group of Tyr69 hydrogen bonds to the second
anionic O atom of the phosphate group while that of the phosphonate group
replaces the third water, 'catalytic' water, which forms a hydrogen bond to
Ndelta1 of His48. The fourth water which also shares Ndelta1 of His48 is
displaced by the steric hinderance of the inhibitor. The fifth conserved
structural water is still present in the active site and forms a network of
hydrogen bonds with the surrounding residues. The structure is compared to the
other known TSA-PLA2 complexes.
PMID- 9761901
TI - 1.72 A resolution refinement of the trigonal form of bovine pancreatic
phospholipase A2.
AB - The trigonal crystal structure of the recombinant bovine pancreatic phospholipase
A2 has been re-refined at a slightly higher resolution (1.72 A). The crystals are
trigonal, space group P3121, unit-cell parameters a = b = 46.78 and c = 102.89 A
and are isomorphous to the previous structure. The structure was refined to a
final crystallographic R value of 19.5% (Rfree = 28.4%) using 10 531 reflections.
A total of 106 solvent molecules were included in the refinement compared with
the earlier refinement which contains only 85 water molecules and 8 925
reflections at 1.8 A resolution. The root-mean-square deviation from the ideal
bond lengths and bond angles is considerably better in the present refinement.
The active site is extended ( approximately 14 A) from Ala1 to the calcium. The
three catalytic residues (Asp99, His48 and the catalytic water) are connected by
the conserved structural water and the N-terminal Ala1 on one side, and by the
calcium through an equatorial water on the other. The water molecules play a role
in the activity of the enzyme PLA2. The Ala1 end of the extended active site
performs the activation of the phospholid membranes while the opposite end
performs the hydrolysis of the monomeric phospholids.
PMID- 9761902
TI - Structure of azurin I from the denitrifying bacterium Alcaligenes xylosoxidans
NCIMB 11015 at 2.45 A resolution.
AB - Azurin I from Alcaligenes xylosoxidans NCIMB 11015 (AzN-I) was crystallized by
using PEG 4000 as a precipitant. The crystals belong to the monoclinic crystal
system and have a space group C2 with the unit-cell parameters of a = 130.67, b =
54.26, c = 74.55 A, and beta = 95.99 degrees. The structure of AzN-I has been
solved by the molecular replacement method. Azurin II from the same bacterium
(AzN-II) was chosen as the initial structural model. The final crystallographic R
value is 17.3% and free R value is 23.6% for 10958 reflections at a resolution of
2.45 A. The root-mean-square deviations for main-chain atoms range between 0.19
and 0.26 A among the four independent molecules in the asymmetric unit. The Cu
atom is coordinated to Ndelta of His46 and His117 at 2.0 (1) and 1.9 (1) A, and
to Sgamma of Cys112 at 2.2 (1) A, while the carbonyl O atom of Gly45 and Sdelta
of Met121 coordinate axially to Cu atom at 2.5 (1) and 3.1 (1) A, respectively.
The Cu-N and Cu-S distances of AzN-I are quite similar to those of AzN-II,
however, the Cu-SO (Gly45) bond length in AzN-I is 0.25 A shorter than the
counterpart in AzN-II. The results have been used to discuss the differences in
the spectra of these two proteins.
PMID- 9761903
TI - Human carboxyhemoglobin at 2.2 A resolution: structure and solvent comparisons of
R-state, R2-state and T-state hemoglobins.
AB - The three-dimensional structure and associated solvent of human carboxyhemoglobin
at 2.2 A resolution are compared with other R-state and T-state human hemoglobin
structures. The crystal form is isomorphous with that of the 2.7 A structure of
carboxyhemoglobin reported earlier [Baldwin (1980). J. Mol. Biol. 136, 103-128],
whose coordinates were used as a starting model, and with the 2.2 A structure
described in an earlier report [Derewenda et al. (1990). J. Mol. Biol. 211, 515
519]. During the course of the refinement, a natural mutation of the alpha
subunit, A53S, was discovered that forms a new crystal contact through a bridging
water molecule. The protein structure shows a significant difference between the
alpha and beta heme geometries, with Fe-C-O angles of 125 and 162 degrees,
respectively. The carboxyhemoglobin is compared with other fully ligated R-state
human hemoglobins [Baldwin (1980). J. Mol. Biol. 136, 103-128; Shaanan (1983). J.
Mol. Biol. 195, 419-422] with the R2-state hemoglobin [Silva et al. (1992). J.
Biol. Chem. 267, 17248-17256] and with T-state deoxyhemoglobin [Fronticelli et
al. (1994). J. Biol. Chem. 269, 23965-23969]. The structure is similar to the
earlier reported R-state structures, but there are differences in many side-chain
conformations, the associated water structure and the presence and the position
of a phosphate ion. The quaternary changes between the R-state carboxyhemoglobin
and the R2-state and T-state structures are in general consistent with those
reported in the earlier structures. The location of 238 water molecules and a
phosphate ion in the carboxyhemoglobin structure allows the first comparison of
the solvent structures of the R-state and T-state structures. Distinctive
hydration patterns for each of the quaternary structures are observed, but a
number of conserved water molecule binding sites are found that are independent
of the conformational state of the protein.
PMID- 9761904
TI - Structure refinement against synchrotron Laue data: strategies for data
collection and reduction.
AB - The synchrotron Laue technique has been applied to high-resolution structure
refinement of the ribotoxin, restrictocin [Yang & Moffat (1996). Structure, 4,
837-852]. By employing carefully designed data-collection strategies and the data
reduction algorithms incorporated in the software system LaueView [Ren & Moffat
(1995a). J. Appl. Cryst. 28, 461-481; Ren & Moffat (1995b). J. Appl. Cryst. 28,
482-493], a set of high-resolution Laue data with a completeness and accuracy
comparable to excellent monochromatic data was obtained. Through detailed
comparison with the monochromatic data and electron-density maps derived from the
Laue data, optimum data-collection and reduction strategies were identified and
the application of Laue diffraction techniques to conventional crystallographic
refinement was demonstrated.
PMID- 9761905
TI - Structure analysis of two CheY mutants: importance of the hydrogen-bond
contribution to protein stability.
AB - The crystal structures of two double mutants (F14N/V21T and F14N/V86T) of the
signal transduction protein CheY have been determined to a resolution of 2.4 and
2.2 A, respectively. The structures were solved by molecular replacement and
refined to final R values of 18.4 and 19.2%, respectively. Together with urea
denaturation experiments the structures have been used to analyse the effects of
mutations where hydrophobic residues are replaced by residues capable of
establishing hydrogen bonds. The large increase in stabilization (-12.1 kJ mol-1)
of the mutation Phe14Asn arises from two factors: a reverse hydrophobic effect
and the formation of a good N-cap at alpha-helix 1. In addition, a forward
backward hydrogen-bonding pattern, resembling an N-capping box and involving
Asn14 and Arg18, has been found. The two Val to Thr mutations at the hydrophobic
core have different thermodynamic effects: the mutation Val21Thr does not affect
the stability of the protein while the mutation Val86Thr causes a small
destabilization of 1.7 kJ mol-1. At site 21 a backward side chain-to-backbone
hydrogen bond is formed inside alpha-helix 1 with the carbonyl O atom of the i -
4 residue without movement of the mutated side chain. The destabilizing effect of
introducing a polar group in the core is efficiently compensated for by the
formation of an extra hydrogen bond. At site 86 the new Ogamma atom escapes from
the hydrophobic environment by a chi1 rotation into an adjacent hydrophilic
cavity to form a new hydrogen bond. In this case the isosteric Val to Thr
substitution is disruptive but the loss in stabilization energy is partly
compensated by the formation of a hydrogen bond. The two crystal structures
described in this work underline the significance of the hydrogen-bond component
to protein stability.
PMID- 9761907
TI - Determination of the relative precision of atoms in a macromolecular structure.
AB - Several real-space indices and temperature factors are compared with respect to
their correlation with atomic positional error and their ability to indicate
atoms and residues with the worst of subtle errors. The best index, rED, is a
correlation coefficient between model and map electron densities, similar to one
proposed earlier, but incorporating two improvements. Firstly, resolution is
accounted for explicitly by calculating the model electron density by Fourier
transformation of resolution-truncated scattering factors. Secondly, the
deviation between model and map electron densities is assigned to neighboring
atoms according to their contribution to the electron density of each grid point.
With maps of various qualities, rED is the single index with best correlation to
atomic error with grouped or individual atoms, and it is the most reliable
indicator of poor residues. With poorer omit maps, imprecision of individual
atoms is best diagnosed by a combination of low rED or high B factor. With the
improved methods, 60-70% of the least precise atoms can detected in a fully
refined structure. Similarly, 40-80% of the least precise atoms of an unrefined
model can be detected by comparison with an isomorphous replacement map. This is
useful in assessing and improving the quality of a model, but not sufficient to
confidently validate all atoms of a structure at sub-atomic resolution.
PMID- 9761908
TI - A translation-function approach for heavy-atom location in macromolecular
crystallography.
AB - A method for locating heavy atoms in the unit cell of macromolecular crystals by
a full-symmetry translation function is described. The approach has been
implemented in the program TRAHALO and tested on experimental isomorphous and
anomalous data.
PMID- 9761909
TI - Crystallization and preliminary X-ray investigation of the complex of RNase Sa
with wild-type barstar.
AB - RNase Sa, an extracellular ribonuclease produced by Streptomyces aureofaciens, is
inhibited by barstar, the natural protein inhibitor of barnase, the ribonuclease
of Bacillus amyloliquefaciens. The complex of RNase Sa with wild-type barstar was
crystallized by hanging-drop vapour diffusion. It was shown by sodium dodecyl
sulfate polyacrylamide gel electrophoresis that RNase Sa and barstar are present
in equimolar proportions in the crystals. The crystals are in the hexagonal space
group P65 with unit cell dimensions a = b = 56.95, c = 135.8 A. They diffract to
1.7 A resolution at the DESY synchronton source. The asymmetric unit contains one
molecule of the complex.
PMID- 9761910
TI - Crystallization of two hCG-specific monoclonal antibody fragments.
AB - The Fab fragments of two monoclonal antibodies (Fab3A2, Fab6A) raised against
epitopes of human chorionic gonadotrophin (hCG) have been crystallized using the
vapour-diffusion technique. The Fab3A2 antibody recognises an epitope on the C
terminal peptide of the beta-subunit and the Fab6A a conformational epitope of
hCG. Both Fab crystals grow as hexagonal rods from ammonium sulfate solutions.
The Fab3A2 crystals belong to space group P3121 with a = b = 74.84, c = 198.2 A
and diffract to 1.33 A at the ESRF. The Fab6A crystals are in the space group
P3221 with a = b = 129.53, c = 74.40 A and diffract to 2.7 A at the Daresbury
SRS. One Fab molecule per asymmetric unit is present in both crystals.
PMID- 9761911
TI - Crystallization of the alanine dehydrogenase from Phormidium lapideum.
AB - Amino-acid dehydrogenases catalyse the interconversion of their respective amino
acids to the corresponding keto acid, with concomitant reduction of NAD or NADP.
The enzymes phenylalanine, glutamate, leucine and valine dehydrogenase all share
a similar three-dimensional subunit structure and a high degree of sequence
similarity, indicating that they belong to an enzyme superfamily related by
divergent evolution. In contrast, alanine dehydrogenase shows no sequence
similarity with any of these enzymes despite catalysing a reaction with the same
chemistry and thus it is predicted that it possesses a different three
dimensional structure. The alanine dehydrogenase from Phormidium lapideum has
been crystallized in space group R32, cell dimensions a = b = 123.1 and c = 184.8
A, with a monomer in the asymmetric unit. The structure determination of this
enzyme will shed light on how nature has evolved two different systems to carry
out the same reaction.
PMID- 9761912
TI - Crystallization and preliminary high-resolution X-ray diffraction analysis of
native and beta-mercaptoethanol-inhibited urease from Bacillus pasteurii.
AB - Hexagonal crystals of urease from Bacillus pasteurii have been obtained by vapour
diffusion at 293 K in 20 mM Tris-HCl, neutral pH, containing 50 mM Na2SO3.
Isomorphous crystals of urease inhibited with beta-mercaptoethanol were also
obtained by including 4 mM of the inhibitor in the enzyme solution. Crystals of
the native and inhibited enzyme diffract respectively to 2.00 A (96.7%
completeness) and to 1.65 A (98.7% completeness) using synchrotron X-ray
cryogenic (100 K) conditions. The space group is P6322 for both forms, and the
unit-cell parameters are a = b = 131.36, c = 189. 76 A for native urease and a =
b = 131.34, c = 190.01 A for inhibited urease. Under the same conditions, single
crystals of B. pasteurii urease inhibited with acetohydroxamic acid, cisteamine,
and phenylphosphorodiamidate were also obtained.
PMID- 9761913
TI - Crystallization and preliminary X-ray diffraction studies of homoserine
dehydrogenase from Saccharomyces cerevisiae.
AB - Recombinant homoserine dehydrogenase from Saccharomyces cerevisiae has been
crystallized in three different forms. Crystals of the apo-enzyme belong to the
tetragonal space group P4 and have unit-cell-dimensions a = b = 130 and c = 240
A. The resolution limit for these crystals is 3.9 A. Crystals of homoserine
dehydrogenase grown in the presence of the co-factor NAD+ have the tetragonal
space group P41212 or its enantiomorph P43212. The unit-cell dimensions for these
crystals are a = b = 80.4 and c = 250.2 A, and the observed resolution limit is
2.2 A. Protein crystals grown in the presence of the product L-homoserine and the
inert NAD+ analogue 3-aminopyridine adenine dinucleotide belong to the monoclinic
space group P21 with unit-cell parameters a = 58.8, b = 104.2, c = 120.7 A, beta
= 91.9 degrees. This last crystal form has a diffraction limit of 2.7 A
resolution.
PMID- 9761914
TI - Preliminary X-ray crystallographic analysis of a novel maltogenic amylase from
Bacillus stearothermophilus ET1.
AB - A novel maltogenic amylase from Bacillus stearothermophilus ET1, which has a dual
activity of alpha-1,4- and alpha-1,6-glycosidic bond cleavages and alpha-1,6
glycosidic bond formation, was crystallized by using the hanging-drop vapor
diffusion method. The best crystals were obtained by employing a high
concentration of protein (56 mg ml-1) and a precipitant containing 22% glycerol,
1.6 M ammonium sulfate in 0.1 M Tris-HCl (pH 8.5). Native diffraction data to
2.66 A resolution have been obtained from crystals flash-frozen at 110 K. The
crystals belong to the space group P212121 with unit-cell dimensions of a =
77.62, b = 121.23, c = 244. 29 A, and contain three or four protomers per
asymmetric unit. Structure determination by multiple isomorphous replacement is
in progress.
PMID- 9761915
TI - Crystallization and preliminary X-ray analysis of a member of a new family of
pectate lyases, PeIL from Erwinia chrysanthemi.
AB - PeIL, a pectate lyase (E.C. 4.2.2.9) from E. chrysanthemi 3937 that is not
homologous to the lyases with known structures, has been purified and
crystallized by the hanging-drop method using a variety of organic solvents as
precipitant. Elongated lathes grown from poly(ethylene glycol) plus isopropanol
belong to the space group P212121 with cell dimensions a = 55.5, b = 58.2, c =
16.4 A with a single molecule in the asymmetric unit. Although complete data sets
have been collected to 2.3 A resolution, these crystals diffract to at least 1.9
A resolution and are suitable for structure determination. Chunky plates grown
using other organic solvents as the precipitant diffracted to 3 A resolution and
were partially characterized as a second orthorhombic crystal form with space
group P21212 and cell dimensions a = 119.1, b = 140.5 and c = 105.4 A, suggesting
four molecules in the asymmetric unit.
PMID- 9761916
TI - Crystallization of an intact GST-estrogen receptor hormone binding domain fusion
protein.
AB - Crystals of an intact GST-estrogen receptor hormone binding domain fusion protein
have been grown from solutions of MPD. The crystals grew as clusters of thin
plates and needles of maximum dimensions 100 x 20 x 1 micrometer but were
unsuitable for X-ray diffraction analysis. However, examination by electron
microscopy shows an ordered lattice in which the protein molecules are clearly
visible. Image analysis of electron micrographs of the protein crystals revealed
electron stain-excluding density which showed a two-domain trimeric structure in
projection, with each molecule of dimensions 12.0 x 5.0 nm diameter. The use of
GST-fusion proteins in crystallisation are discussed.
PMID- 9761917
TI - Crystallization of the NADP-dependent beta-keto acyl carrier protein reductase
from Escherichia coli.
AB - The NADP-dependent beta-keto acyl carrier protein reductase (BKR) from E. coli
has been crystallized by the hanging-drop method of vapour diffusion using
poly(ethylene glycol) of average molecular weight 1450. The crystals belong to
the hexagonal space group P6122 or P6522 with unit-cell dimensions a = b = 67.8,
c = 355.8 A. Calculated values for Vm and consideration of the packing suggest
that the asymmetric unit contains a dimer. BKR catalyses the first reductive step
in the elongation cycle of fatty-acid biosynthesis. It shares extensive sequence
homology with the enzyme which catalyzes the second reductive step in the cycle,
enoyl acyl carrier protein reductase (ENR), and thus provides an opportunity to
study the evolution of enzyme function in a metabolic pathway. The structure
determination will permit the analysis of the molecular basis of its catalytic
mechanism and substrate specificity.
PMID- 9761918
TI - Crystallization and preliminary X-ray diffraction studies of the catalytic core
of acetyl xylan esterase from Trichoderma reesei.
AB - Acetyl xylan esterase is involved in the biodegradation of hemicellulose. It
cleaves O-acetyl groups from xylan, which is the most abundant hemicellulose in
nature. The catalytic core of acetyl xylan esterase from T. reesei has been
crystallized and X-ray diffraction data at 2.3 A collected. The crystal belongs
to the triclinic space group P1 with unit-cell parameters a = 50.3, b = 62. 1, c
= 40.0 A, alpha = 110.1, beta = 113.6 and gamma = 97.9 degrees. The asymmetric
unit contains two molecules.
PMID- 9761919
TI - Crystallization and preliminary diffraction studies of the extracellular region
of human p58 killer cell inhibitory receptor (KIR2).
AB - Molecules of the human killer cell inhibitory receptor (KIR) family, which belong
to the immunoglobulin superfamily (IgSF), are expressed on the surface of natural
killer (NK) cells and some subsets of T cells. These receptors function to
mediate the inhibition or activation of cytotoxic activity by recognizing HLA
class I molecules on the target cell. The extracellular region of a p58 KIR
specific for HLA-Cw1,3,7 (KIR2) has been overproduced in Escherichia coli and
purified. The recombinant KIR2 has been crystallized in 9-10% poly(ethylene
glycol) methyl ether (average Mr = 8000), 50mM HEPES, 8% ethylene glycol, 0.5%
octyl-beta-glucoside, pH 7.5, at 294 K using the sitting-drop vapour-diffusion
method. Preliminary X-ray diffraction studies reveal the space group to be
hexagonal (P6122 or P6522) with lattice constants a = b = 95.3, c = 130.8 A. A
native data set (3 A resolution) has been collected at the Photon Factory (lambda
= 1.0 A).
PMID- 9761920
TI - Crystallization and preliminary X-ray studies of hORF6, a novel human antioxidant
enzyme.
AB - HORF6 is a member of the novel antioxidant enzyme family found in humans. A
recombinant form of hORF6 expressed and purified from E. coli has been
crystallized by the hanging-drop method using various PEG's as precipitating
agents. HORF6 crystallizes in two different monoclinic space groups, P21 and C2.
The P21 crystals have unit-cell dimensions of a = 47.85, b = 75.17, c = 63.30 A
and beta = 110.21 degrees and contain two monomers per asymmetric unit, while the
C2 crystals have unit-cell dimensions of a = 165.27, b = 95.44, c = 166.44 A and
beta = 128.97 degrees and contain more than six monomers per asymmetric unit. The
P21 crystals with the smaller unit cell diffract X-rays better and behave well
for the X-ray analysis. A native data set from a single crystal of the P21 space
group gas been collected to 2.0 A resolution.
PMID- 9761921
TI - Crystallization and preliminary X-ray diffraction studies of E. coli
porphobilinogen synthase and its heavy-atom derivatives.
AB - Porphobilinogen synthase (PBGS) catalyzes the condensation of two identical
substrate molecules, 5-aminolevulinic acid (ALA), in an asymmetric manner to form
porphobilinogen. E. coli PBGS is an homooctameric enzyme. The number of active
sites is not clear, but each subunit binds one ZnII ion and one MgII ion.
Diffraction-quality crystals of native E. coli PBGS have been obtained, and unit
cell dimensions (a = 130.8, c = 144.0 A) are reported. These crystals diffract to
about 3.0 A resolution.
PMID- 9761922
TI - Preliminary X-ray crystallographic analysis of Bowman-Birk trypsin inhibitor from
barley seeds.
AB - Bowman-Birk trypsin inhibitor from barley seeds has been crystallized at room
temperature using polyethylene glycol as precipitant. The crystal is tetragonal,
belonging to the space group P41212 (or P43212), with unit cell parameters of a =
b = 62.48 and c = 94.63 A. The asymmetric unit contains one molecule of Bowman
Birk trypsin inhibitor with corresponding crystal volume per protein mass (Vm) of
2.89 A3 Da-1 and the solvent content of 57% by volume. The crystals diffract to
at least 1.9 A Bragg spacing upon exposure to synchrotron X-rays. X-ray data to
1.9 A have been collected from a native crystal.
PMID- 9761923
TI - Crystallization and preliminary X-ray studies on the hyperstable 3
isopropylmalate dehydrogenase from the thermoacidophilic archaeon Sulfolobus sp.
strain 7.
AB - 3-Isopropylmalate dehydrogenase from the thermoacidophilic archaeon, Sulfolobus
sp. strain 7, has been crystallized by the vapor-diffusion method. The crystals
were grown from a solution containing ammonium sulfate, 2-methyl-2,4-pentanediol
and magnesium chloride. The crystallization requires 2-methyl-2,4-pentanediol to
avoid twinning of the crystals. The crystal belongs to the orthorhombic system
with the space group P2221 and unit-cell dimensions a = 67.9, b = 93.3 and c =
134.1 A.
PMID- 9761924
TI - Purification, crystallization and preliminary X-ray diffraction studies on the
thermostable catechol 2,3-dioxygenase of Bacillus stearothermophilus expressed in
Escherichia coli.
AB - The thermostable catechol 2,3-dioxygenase of Bacillus stearothermophilus has been
crystallized. The crystal is probably in the space group I222 with unit-cell
dimensions of a = 70.87, b = 74.60 and c = 133.69 A. A native data set has been
collected with a completeness of 96% at 2.22 A resolution and an Rmerge value of
0.091.
PMID- 9761925
TI - Crystallization and preliminary X-ray analysis of thiaminase I from Bacillus
thiaminolyticus: space group change upon freezing of crystals.
AB - Thiaminase I (Mr = 42 100) from B. thiaminolyticus, expressed in E. coli, has
been crystallized by the vapor-diffusion method. Three crystal forms, two of
which grew from 0.1 M sodium acetate (pH = 4.6), 0.2 M ammonium sulfate and
30%(w/v) PEG 2000, have been examined by X-ray analysis. One crystal form
diffracted to 2.5 A at room temperature, was orthorhombic, and had unit-cell
edges of a = 87.7, b = 120.5 and c = 76.7 A with space group P212121. A self
Patterson map showed a strong peak indicating noncrystallographic translational
pseudosymmetry with (u, v, w) = (0.03, 0.0, 0.5). When these crystals were frozen
at liquid-nitrogen temperatures, a second crystal form was observed which had
unit-cell dimensions a = 85.5, b = 117.5 and c = 36.6 A with space group P21212.
A third crystal form grew from 0.1 M Tris (pH = 8.5), 0.2 M sodium acetate
trihydrate and 28%(w/v) PEG 6000 to produce orthorhombic crystals of space group
P212121 with cell edges of a = 114.4, b = 123.1 and c = 92.5 A.
PMID- 9761926
TI - Expression, purification, crystallization and crystallographic characterization
of the human MHC class I related protein MICA.
AB - Crystals of the human MHC-encoded molecule MICA, a homologue of MHC class I
proteins, have been grown in hanging-drop vapor-diffusion trials using ammonium
sulfate as a precipitating agent with recombinant protein expressed in a
baculovirus-based system. Cryo-preserved crystals of MICA belong to the cubic
space group F4132 with lattice constants a = b = c = 260.7 A and diffract to a
resolution limit of 3.0 A when cryo-preserved. These crystals do not diffract
when handled conventionally.
PMID- 9761927
TI - Preliminary X-ray analysis of a new crystal form of the vanadium-dependent
bromoperoxidase from Corallina officinalis.
AB - A new crystal form of the vanadium-dependent bromoperoxidase from Corallina
officinalis has been obtained. The crystals exhibit a 'teardrop' morphology and
are grown from 2 M ammonium dihydrogen phosphate pH and diffract to beyond 1.7 A
resolution. They are in tetragonal space group P4222 with unit-cell dimensions of
a = b = 201.9, c = 178.19 A, alpha = beta = gamma = 90 degrees. A 2.3 A
resolution native data set has been collected at the Hamburg Synchrotron. A
mercury derivative data set has also been collected, and the heavy-atom positions
have been determined. The self-rotation function and the positions of the heavy
atoms are consistent with the molecule being a dodecamer with local 23 symmetry.
PMID- 9761928
TI - Expression, crystallization and preliminary X-ray analysis of ligand-free human
glutathione S-transferase M2-2.
AB - Human glutathione-S-transferase M2-2 (hGSTM2-2) was expressed in Escherichia coli
and purified by GSH-affinity chromatography. The recombinant enzyme and the
protein isolated from human tissue were indistinguishable based on
physicochemical, enzymatic and immunological criteria. The catalytically active
dimeric hGSTM2-2 was crystallized without GSH or other active-site ligands in two
crystal forms. Diffraction from form A crystals extends to 2.5 A and is
consistent with the space group P21 (a = 53.9, b = 81.5, c = 55.6 A, beta =
109.26 A) with two monomers in the asymmetric unit. Diffraction from form B
crystals extends to 3 A and is consistent with a space group P212121 (a = 57.2, b
= 80.7, c = 225.9 A) with two dimers in the asymmetric unit. This is the first
report of ligand-free mu-class GST crystals, and a comparison with liganded
complexes will provide insight into the structural consequences of substrate
binding which are thought to be important for catalysis.
PMID- 9761929
TI - Enhanced electron-density envelopes by extended solvent definition.
AB - Extended delineation of water molecules, monitored using Rfree values, afforded
considerable improvement in quality of electron-density maps for structure
determination of mammalian class I and E. coli class II aldolases. Augmented
solvent definition results in an additional decrease in Rfree values of 3-4% and
is reflected in significantly enhanced electron-density envelopes enabling
tracing of amino-acid sequences through regions of otherwise discontinuous or
weak electron density.
PMID- 9761930
TI - Polymorphous crystallization and diffraction of threonine deaminase from
Escherichia coli.
AB - The biosynthetic threonine deaminase from Escherichia coli, an allosteric
tetramer with key regulatory functions, has been crystallized in several crystal
forms. Two distinct forms, both belonging to either space group P3121 or P3221,
with different sized asymmetric units that both contain a tetramer, grow under
identical conditions. Diffraction data sets to 2.8 A resolution (native) and 2. 9
A resolution (isomorphous uranyl derivative) have been collected from a third
crystal form in space group I222.
PMID- 9761931
TI - An improved procedure for the preparation of X-ray diffraction-quality crystals
of cytochrome p450cam.
AB - A procedure for the crystallization of recombinant cytochrome P450cam has been
developed which avoids the difficulties inherent in the glass-capillary free
interface diffusion method reported previously. The surface mutation, Cys334-
>Ala (C334A), originally designed to prevent dimer formation and thus improve
routine handling of the enzyme, facilitates crystallization by the hanging-drop
vapour-diffusion technique. Crystals of (C334A)P450cam grow within 48 h and
diffract to beyond 1.2 A at 100 K in-house on a Siemens multiwire area detector.
Data have been collected from the camphor-bound form to 1.35 A.
PMID- 9761932
TI - Crystallographic studies of casein kinase I delta toward a structural
understanding of auto-inhibition.
AB - A recombinant form of mammalian casein kinase I delta (CKIdelta) containing the
catalytic domain and an auto-inhibitory domain was expressed in Escherichia coli,
purified and crystallized. X-ray data were collected to 2.4 A resolution, and the
crystals belong to space group C2221. Molecular replacement using the structure
of the catalytic domain of CKIdelta yielded strong electron density for residues
in the model, but no interpretable density was found for the inhibitory domain. A
conserved intermolecular contact suggests the formation of dimers which would
inhibit the activity of this protein kinase.
PMID- 9761933
TI - Expression, purification, crystallization and preliminary X-ray diffraction
analysis of human uroporphyrinogen decarboxylase.
AB - A recombinant human uroporphyrinogen decarboxylase (E.C. 4.1.1.37, UROD) has been
expressed in Escherichia coli and purified to homogeneity. Crystals grew by the
hanging-drop vapor-diffusion technique from a starting solution containing 1.5 mg
ml-1 protein. The crystals belong to the trigonal space group P3121 or its
enantiomer P3221 and diffract to 3 A resolution. The unit-cell parameters are a =
b = 103.4, c = 75.7 A and gamma = 120 degrees. The asymmetric unit contains one
molecule. Preliminary structural predictions suggest for the protein a TIM-barrel
type tertiary structure.
PMID- 9761934
TI - A flash-annealing technique to improve diffraction limits and lower mosaicity in
crystals of glycerol kinase.
AB - A flash-annealing method has been developed that increases the diffraction
limits, and simultaneously decreases the mosaicity of glycerol kinase crystals.
This technique utilizes brief thawing and rapid freezing cycles of the crystal in
the cold nitrogen stream. The effective resolution limits increased almost by 0.8
A, from 3.6 to 2.8 A, and mosaicity values halved.
PMID- 9761935
TI - Benefits of pharmacological knowledge in the design and monitoring of cancer
chemotherapy.
AB - Prescribing chemotherapy is a difficult task, because of drug resistance, which
prevents all tumors to respond to a given protocol and because of drug toxicity,
which is generally unavoidable but which must be limited to acceptable levels.
The therapeutic window of anticancer drugs is very narrow and clinicians have to
try to optimize the individual doses and schedules of the drugs to be
administered. They can rely upon simple anthropometric features, such as body
weight or surface area; they can also take into account the physiological status
of the patient: age, liver and kidney function, genetic characteristics of drug
metabolism, etc. The best way for dose adaptation lies in the establishment of
pharmacokinetic/pharmacodynamic relationships, i.e., between the behavior of a
drug in the body and its efficacy and toxicity. When it is established that the
optimal effect of a drug is related to a given parameter, such as the area under
the curve plotting plasma concentration vs. time (AUC), it becomes possible to
administer the drug with the dose allowing to obtain the target parameter value.
Individual dose adaptation can be achieved thanks to the study of the
pharmacokinetics of a test dose preceding that of the therapeutic dose, or by the
measure of drug plasma levels, either at steady state during a protracted
infusion, or from cycle to cycle during repetitive protocols. Population analysis
now allows the adaptation of anticancer drug dosing from a minimum knowledge of
individual pharmacokinetic features, together with other characteristics of the
patients such as age, gender or physiological functions.
PMID- 9761936
TI - BMD188, A novel hydroxamic acid compound, demonstrates potent anti-prostate
cancer effects in vitro and in vivo by inducing apoptosis: requirements for
mitochondria, reactive oxygen species, and proteases.
AB - A newly synthesized cyclic hydroxamic acid compound, BMD188 [cis-1-hydroxy-4-(1
naphthyl)-6-octylpiperidine-2-one], was found to induce the apoptotic death of
cultured prostate cancer cells by activating caspase-3. Orally administered
BMD188 significantly inhibited the primary growth of prostate cancer cells
(Du145) orthotopically implanted into SCID mice. Mechanistic studies indicated
that BMD188 did not alter the protein levels of several Bcl-2 family members. In
contrast, the BMD188 effect required three essential factors: reactive oxygen
species (ROS), the mitochondrial respiratory chain function, and proteases.
First, the apoptosis-inducing effect of BMD188 could be blocked by ROS scavengers
such as Desferal. Second, both BMD188-induced PARP cleavage as well as PC3 cell
apoptosis could be dramatically inhibited by several complex-specific
mitochondrial respiration blockers. The involvement of mitochondria was also
supported by the observations that BMD188 dramatically altered the mitochondrial
distribution and morphology without affecting the cellular ATP levels. Finally,
the apoptosis-inducing effect of BMD188 in PC3 cells could be significantly
inhibited by serine protease inhibitors (TPCK and TLCK) as well as by caspase
inhibitors (zVAD-fmk and DEVD-CHO). Collectively, the present study suggests that
BMD188 and its analogs may find clinical applications in the treatment of
prostate cancer patients by inducing apoptotic death of prostate cancer cells.
PMID- 9761937
TI - Combined in vitro effect of marijuana and retrovirus on the activity of mouse
natural killer cells.
AB - Both marijuana and retroviruses impair natural killer (NK) cell functions. No
data on their simulataneous effects are available. Similarities to human AIDS
induced early by Friend leukemia complex (FLC) and its replication competent
helper Rowson-Parr virus (RPV) provides a mouse model to study drug-virus action.
Leukemia susceptible BALB/c and resistant C57BL/6 mice were infected, then at
time intervals their nylon wool-separated splenocytes were exposed to
tetrahydrocannabinol (THC) for 3h. Natural killer (NK) cell activity against Yac
1 cells was assayed by 51Cr-release for 4 and 18h. Recovery of splenocytes was
found to be suppressed by FLC, but in BALB/c only by RPV. After a transient
enhancement in C57BL/6 by FLC, NK cell activity of both mice became suppressed
early (2 to 4 days), normalized subsequently and enhanced late (11 to 14 days)
postinfection. A moderate increase in BALB/c, no change in C57BL/6 were induced
by low (1-2.5 microgram/ml) THC doses. NK cell activity of BALB/c became
suppressed exponentially by higher (5-10 microgrtam/ ml) THC doses in 18h as
compared to 4h assays, while its proportional and moderate impairment was seen in
C57BL/6. The magnitude of NK cell activity of infected mice was determined by
THC: enhancement or impairment followed those of untreated, infected
counterparts, but on the level of THC-treated cells. Low doses hardly, high doses
additively influenced NK cells of infected BALB/c. THC hardly affected very early
and late enhancement in NK cell activiy of FLC infected C57BL/6, but augmented
RPV induced suppression late in 18h assays. Genetic factors similar to endotoxin
resistance, altered cytokine profile might determine these effects. Similar
phenomena in humans might result in earlier manifestation of AIDS.
PMID- 9761938
TI - EBER oligonucleotide RNA in situ hybridization in EBV associated neoplasms.
AB - In virus associated diseases identification of viruses in cells can contribute to
the understanding of the pathogenesis and may also help to establish the
diagnosis. In the present communication, the effects of the microwave
pretreatment (MWP) and that of the proteinase-K enzymatic predigestion (PKD) on
EBER RNA oligonucleotide in situ hybridization (EBER-RNA-ISH) (EBER: Epstein-Barr
Encoded-(Early)-RNA) were studied. The efficacy of two EBV detecting methods,
latent membrane protein-1 (LMP-1) immunohistochemistry and EBER-RNA-ISH were also
compared. Our results show that microwave pretreatment enhances the intensity of
the ISH signals and preserves significantly better the structure of the tissues
compared with enzymatic predigestion. EBER-RNA-ISH, mainly in the nasopharyngeal
carcinoma cases, showed a more frequent positivity than the immunohistochemical
reaction for LMP-1, however in case of the Warthin's tumor only the LMP-1 protein
was expressed.
PMID- 9761939
TI - Fibrinolytic activity of earthworms extract (G-90) on lysis of fibrin clots
originated from the venous blood of patients with malignant tumors.
AB - u-PA is secreted by the most malignant tumors. As a response to u-PA synthesis
surrounding cells synthetize inhibitors of plasminogen activators for tissue
protection. Plasminogen activators were found also in earthworm tissue. From the
tissue homogenate of earthworm Eisenia foetida the glycolipoprotein mixture named
G-90 was isolated. It contains two serine proteases (P I, P II) with fibrinolytic
and anticoagulative activities. The fibrinolytic activity of G-90, P I and P II
was tested in an in vitro euglobulinic test applied to fibrin clot from blood
plasma of patients suffered from malignant tumors. G-90 and above-mentioned
proteases applied in this study showed euglobulinic time proportionally with the
concentrations of added substances. The influence of G-90 on the fibrinolysis
rate does not depend only on its concentration, but depends too on histological
type of tissue (organ) where the malignant tumors are located. Enzyme P I and P
II do not show this activity.
PMID- 9761940
TI - Corpus amylaceum (polyglucosan body) in the peripheral olfactory system.
AB - Peripheral part of the olfactory system (bulb and tract) was investigated for the
occurrence of corpus amylaceum (CA) (polyglucosan body) in 296 (281 pathological
and 15 control cases) autopsied human brains. No significant differences were
found in the incidence between the various age groups above 40 years or between
different disease groups and the controls. The predominance of CA in the
olfactory tract and its loose correlation with age at this localization over 40
years of age could be resulted by various factors, including the extremely rich
astrocytic and capillary network in the intermediate zone, and the proximity of
the olfactory tract to the external environment, which may result in the
protective role of CA. The role of stress was proved by the HSP-60 positivity of
CA.
PMID- 9761941
TI - A new method to localize acid phosphatase using the confocal laser-scanning
microscope.
AB - The aim of the study was to work out a technique for the detection of acid
phosphatase enzyme activity by confocal laser-scanning microscope using the
histochemical acid phosphatase detection method (after Barka and Anderson 1962,
modified by Bowen and Lewis 1985) routinely used for light microscopy. The
density and the distribution of enzyme reaction product is dependent on the
incubation time, as shown by different confocal images or ELISA reader. The
inhibition of the enzyme activity with metal ions shows the same profile known
from the literature. This staining method seems to be useful to demonstrate
subcellular distribution of the enzyme in the lysosomes and in the Golgi
apparatus.
PMID- 9761942
TI - A novel in vitro system to study extravasated tumor cell-induced angiogenesis.
AB - Angiogenesis, the formation of new blood vessels from preexisting ones, is a
fundamental stage in the metastatic pathway. For the primary tumor, this
neovascularization provides nutrients and oxygen as well as a route by which
metastatic tumor cells gain access to the circulatory system. Among these
metastatic tumor cells, there are subgroups of cells that express an angiogenesis
inducing cells phenotype (AICs) as well as others that do not. Tumor cells not
expressing the angiogenesis-inducing cells phenotype (non-AICs) invade new
tissues and remain as dormant micrometastases unless they accompany AICs. Thus,
either alone or with non-AICs, angiogenesis-inducing cells form rapidly growing,
clinically detectable metastases. Much of the current research in this area is
concentrated on the vascularization of primary tumors, but the regulation of
angiogenesis by extravasating or invading tumor cells has not being extensively
studied. We have developed a working model, which demonstrates that human
metastatic prostate cancer cells (PC-3) appear to induce human vascular
endothelial cells (HUVECs) to translocate across a Matrigel-coated 8 mm membrane.
The parameters of this model (i.e. pore size, seeding-cell density, seeding
times) were established using highly invasive murine melanoma cells (B16F10)
seeded on murine microvascular endothelial cells (CD3). We have further modified
our model in order to include a host compartment made of collagen gel, in order
to mimic the in vivo site of metastases-induced angiogenesis.
PMID- 9761944
TI - Phenotypes of T cells in the gut.
PMID- 9761946
TI - Mucosal T cell-epithelial cell interactions.
PMID- 9761945
TI - T-cell receptor usage in the intestine.
PMID- 9761947
TI - Beta 7 integrins and their ligands in lymphocyte migration to the gut.
PMID- 9761943
TI - Tumor and endothelial cell invasion of basement membranes. The matrigel
chemoinvasion assay as a tool for dissecting molecular mechanisms.
AB - The spread of cancer cells from a primary tumor to distant organs is the major
cause of death of cancer patients. Metastatic lesions are often resistent to
cancer therapy because of the progressive phenotypic changes that they have
undergone. Several genetic and epigenetic factors, both in the cell and in the
host, contribute to the development of tumor progression towards metastases. In
this review we will analyze the steps involved in tumor metastases, which can be
potential targets for anti-metastatic therapy. One of the most critical events in
cancer metastasis is the invasion of basement membranes. An assay which we
developed over ten years ago, the matrigel "chemoinvasion" assay, has been a
useful tool for studying the mechanisms involved in tumor and endothelial cell
invasion of basement membranes and for the screening of anti-invasive agents.
Here we will describe the assay and review some of the major results obtained
with it.
PMID- 9761948
TI - Gamma delta T cells: bodyguards and/or sleepers in the gut.
PMID- 9761950
TI - Lamina propria T cells.
PMID- 9761949
TI - Thymus-independent development of gut T cells.
PMID- 9761951
TI - T cells in mouse models of gut inflammation.
PMID- 9761952
TI - T-cell response to orally administered antigens and its role in the treatment of
autoimmune diseases.
PMID- 9761953
TI - T-cell response to inhaled antigen.
PMID- 9761955
TI - Th1 and Th2 cells and immunity to intestinal helminths.
PMID- 9761954
TI - Role of T cells in asthma.
PMID- 9761956
TI - T cell and cytokine regulation of the IgA response.
PMID- 9761957
TI - Introduction to cell volume regulatory mechanisms.
PMID- 9761958
TI - Cell volume-regulated cation channels.
PMID- 9761959
TI - Cell volume-sensitive chloride channels.
PMID- 9761960
TI - Mechanisms of osmolyte release.
PMID- 9761961
TI - Sensors and signal transduction in the activation of cell volume regulatory ion
transport systems.
PMID- 9761962
TI - Activation of protein kinases upon volume changes: role in cellular homeostasis.
PMID- 9761964
TI - Approaches to identifying cell volume-regulated genes.
PMID- 9761963
TI - Intracellular signaling in response to osmotic stress.
PMID- 9761965
TI - The cytoskeleton in cell volume regulation.
PMID- 9761966
TI - Cell volume regulatory ion transport in cell migration.
PMID- 9761968
TI - Cellular osmoregulation in kidney medulla.
PMID- 9761967
TI - Cell volume in cell proliferation and apoptotic cell death.
PMID- 9761969
TI - Osmoregulation of liver cell function: signalling, osmolytes and cell
heterogeneity.
PMID- 9761970
TI - Volume regulation and 'cross-talk' in sodium-absorbing epithelial cells.
PMID- 9761972
TI - Swelling-activated release of excitatory amino acids in the brain: relevance for
pathophysiology.
PMID- 9761971
TI - Pathophysiology of abnormal cell volume in human red cells.
PMID- 9761973
TI - Coronary artery disease in dialysis patients.
PMID- 9761974
TI - Bacterial infections after renal transplantation.
PMID- 9761975
TI - The use of mycophenolate mofetil (Cellcept) in renal transplantation.
PMID- 9761976
TI - The impact of residual renal function on the adequacy of peritoneal dialysis.
PMID- 9761977
TI - Tacrolimus in kidney transplantation.
PMID- 9761978
TI - Renal disease in the elderly.
PMID- 9761979
TI - Hypertension in the transplanted patient.
PMID- 9761982
TI - Beobachtungsstudien im Rahmen eines naturheilkundlichen Klinikverbunds. teil i:
methoden und ubersicht der ergebnisse in den beteiligten kliniken.
PMID- 9761981
TI - Saliva Collection with Salivettes(R) Is a Sympathetic Stimulus.
PMID- 9761980
TI - Morbidity and mortality on maintenance haemodialysis.
PMID- 9761985
TI - Ozontherapy as a Possible Biological Response Modifier in Cancer.
PMID- 9761983
TI - Methodological Standards and Problems in Preclinical Homoeopathic Potency
Research.
PMID- 9761986
TI - Der aktuelle Stand der Ozontherapie - Empirie und Grundlagenforschung.
PMID- 9761987
TI - Zu den Arbeiten von Bocci und Beck et al.
PMID- 9761988
TI - Antwort der Autoren.
PMID- 9761989
TI - Beobachtungsstudien im Rahmen eines naturheilkundlichen Klinikverbunds.
PMID- 9761990
TI - Naturheilverfahren bei einer Patientin mit chronischer Bronchitis und asthmoider
Reaktion.
PMID- 9761991
TI - Ein auditorisches neurophysiologisches Interventionsverfahren bei Migrane - Eine
offene Anwendungsbeobachtung.
PMID- 9761992
TI - Die Wirkung wassriger Torffraktionen auf die kontraktile Aktivitat von glatter
Muskulatur.
PMID- 9761993
TI - In-vivo-und In-vitro-Versuche zur Erforschung der Wirkungsentfaltung von
Homoopathika.
PMID- 9761994
TI - Beobachtungsstudien im Rahmen eines naturheilkundlichen Klinikverbunds.
PMID- 9761995
TI - Zum Dynamikbegriff Hahnemanns.
PMID- 9761996
TI - Apoptose-Induktion and DNA-Stabilisierung durch Viscum album L.
PMID- 9761998
TI - Chronisch-entzundliche Darmerkrankungen (Colitis ulcerosa; Enteritis regionalis
Crohn): Atiologie und Therapieergebnisse unter Anwendung der bioenergetischen
Funktionsdiagnostik und der Magnetfrequenzakupunktur.
PMID- 9761997
TI - Versuche zur Detektion von Wirkungsunterschieden zwischen Potenz und
gleichkonzentrierter Verdunnung.
PMID- 9761999
TI - Beobachtungsstudien im Rahmen eines naturheilkundlichen Klinikverbunds.
PMID- 9762000
TI - Major Multi-National Pharmaceutical Companies and Complementary Medicine.
PMID- 9762001
TI - Craniofacial growth and dental maturation in short children born small for
gestational age: effect of growth hormone treatment. Own observations and review
of the literature.
AB - Short children born small for gestational age (SGA) may be candidates for
treatment with growth hormone (GH). We examined craniofacial growth and dental
maturation in a cohort of short SGA children. The general growth failure of these
children is reflected to a differential extent within the craniofacial complex.
As a group, these children have a small retrognathic face with a relatively
increased lower anterior face height; in contrast to skeletal maturation, dental
age is not delayed. GH treatment in short prepubertal SGA children leads to
craniofacial catch-up growth, which is particularly pronounced in regions where
interstitial cartilage is involved, the result being that the facial profile
becomes less convex; dental maturation does not appear to be influenced by GH
treatment. In conclusion, in short SGA children, GH treatment does not only
result in an increase of body stature but also in a trend towards normalization
of craniofacial growth and this without notable advancement of dental maturation.
PMID- 9762002
TI - Potential role for growth hormone in human lactation insufficiency.
AB - In order to evaluate the galactopoietic response to rhGH in mothers of normal
babies with idiopathic lactation insufficiency arising in the early postpartum
period, we performed a preliminary, randomised, single blind trial of 3 different
doses of hGH: either 0.05, 0.1, or 0.2 IU/kg/day to a maximum of 16 IU/day, for 7
days. Total 24-hour milk production was determined in each mother 1 day prior to
initiating therapy and on the last day of therapy. Milk production rose by 36.0
+/- 12.6% in the group receiving 0.2 IU/kg/day (n = 6) but by only 4.7 +/- 9.7%,
(p < 0.04) in the combined lower dose group (n = 10). In conclusion, these data
suggest that moderate dose hGH therapy in mothers with lactation insufficiency
can improve galactopoiesis.
PMID- 9762003
TI - Congenital hypothyroidism screening in the West Bank: a test case for screening
in developing regions.
AB - Screening for congenital hypothyroidism (CH) among the Arab population of the
West Bank began in May 1987 as part of the neonatal screening program in Israel.
In the West Bank many infants are born at home or are released from the hospital
on the 1st day after birth and thus cannot be screened. However, we tried to
reach the infants before the age of 1 month at the maternal and child health
centers, where they receive immunization. In this screening program, 64% of the
infants were sampled by the 1st week and 93% by 3 weeks of life. In contrast to
the screening in Israel, where thyroxine determination is followed by thyroid
stimulating hormone measurement, in the West Bank thyroid-stimulating hormone was
tested first in order to decrease the recall rates. From June 1990 to February
1994, 49,694 infants were screened in the West Bank, of whom 24 with CH were
detected (an incidence of 1:2,070). From January 1987 to February 1994, 28,938
infants were screened in East Jerusalem, of whom 20 with CH were detected
(incidence 1:1,447). There were differences between the incidence rates in the
various districts. The incidence rates were higher than those reported from
industrialized countries, but similar to those found in Saudi Arabia. This may be
due to the high degree of consanguineous marriages among Arab populations and to
environmental factors. In conclusion, in spite of the many difficulties, both
practical and political, CH screening in the West Bank is feasible. Although
screening all newborns shortly after birth is not possible, this study shows that
a high percentage of them can be screened at a time when they can still be
effectively treated. Our results could be used in due time as a baseline for a
future independent screening program.
PMID- 9762004
TI - Steroid receptor mRNA levels in human corpus luteum.
AB - To understand the biology of sex steroids in the human corpus luteum, the
expression of estrogen receptor alpha, progesterone receptor, and androgen
receptor mRNA levels was determined by semiquantitative reverse-transcription
polymerase chain reaction-Southern blot analysis. Expression of all receptor
mRNAs was detected in all samples analyzed. Each steroid receptor mRNA level was
significantly lower (p < 0.05) during the late secretory phase than that during
the early or the mid-secretory phase of the endometrium. These findings support
the concept of a local role for sex steroids in modulating the function and life
span of the human corpus luteum.
PMID- 9762005
TI - Does a positive oestrogen feedback on the hypothalamic-pituitary axis exist
concurrently with a defective testosterone feedback in Klinefelter's syndrome?
AB - The oestrogen provocation and GnRH challenge tests were carried out in 5 subjects
with Klinefelter's syndrome who had no history of previous hormonal therapy. The
oestrogen provocation test consisted of an intramuscular injection of 10 mg of
oestradiol valerate and blood samples were collected daily from day 0 to day 5.
In 2 subjects, three GnRH challenge tests were carried out before (day 0) and on
days 2 and 4 after the intramuscular injection of oestradiol valerate. During
each GnRH challenge test, 7 blood samples were collected at 30-min intervals, 30
min and immediately before and for 150 min after the bolus dose of GnRH. Plasma
concentrations of FSH, LH, testosterone and oestradiol were measured by
established radioimmunoassays. Plasma levels of oestradiol rose significantly a
day following the intramuscular injection of 10 mg of oestradiol valerate,
reaching a peak on day 2 and then falling significantly to lower levels by days 4
and 5, although these levels were still significantly higher than the
corresponding baseline levels. In the presence of high levels of oestradiol, the
high basal levels of FSH were significantly suppressed, and remained suppressed
throughout the 5 days of the study. LH, on the other hand, had a biphasic
response; an initial significant suppression by day 1 persisting to day 3, but by
days 4 and 5 a rebound in basal LH levels was noted. However, the levels on day 5
were not significantly higher than baseline levels. The pituitary responsiveness
as far as the LH and FSH secretions were concerned reflected the baseline levels.
The results of the present study refuted the claim that a positive oestrogen
feedback exists in men including Klinefelter's syndrome as a result of the
removal of or reduced testosterone. In addition, the attenuated testosterone
feedback in Klinefelter's syndrome is responsible for the greatly amplified
pituitary responsiveness to the trophic action of GnRH and this, in part, may be
responsible for the elevated levels of FSH and LH seen in such patients.
PMID- 9762006
TI - Plasma levels of insulin-like growth factor (IGF)-I, IGF-II and IGF-binding
protein-3 in the evaluation of childhood growth hormone deficiency.
AB - BACKGROUND: Traditionally, measurement of plasma IGF-I and more recently of IGFBP
3 are used to distinguish GHD from idiopathic short stature in slowly growing
children, using a single blood sample. In earlier studies it was claimed that
IGFBP-3 was superior to IGF-I, but more recently doubts around this claim have
arisen. The role of serum IGF-II has never been studied extensively. On
theoretical grounds, it can also be hypothesized that molar ratios of these
peptides might be of additional value. DESIGN: Retrospective, multicentre, cohort
study. PATIENTS: 96 children evaluated for short stature. METHODS: Serum IGF-I,
IGF-II, IGFBP-3 and various molar ratios were, after correction for age and sex
using SD scores, compared to the maximum serum GH peak after two standard
provocation tests using four different methods (t-test, chi2, likelihood ratios
and ROC curves). In addition, the correlations between these parameters and the
short-term (1 year) and long-term (3 years) response to GH therapy were
calculated. RESULTS: IGF-I performed better than IGFBP-3, but the best results
were achieved by the molar ratio IGF-I:IGF-II. However, IGFBP-3 correlated better
with the short-term response to GH therapy than IGF-I or the ratios, and none of
the parameters investigated was found to be related to the response of long-term
GH therapy.
PMID- 9762007
TI - Regulation of PTP-1 and insulin receptor kinase by fractions from cinnamon:
implications for cinnamon regulation of insulin signalling.
AB - Bioactive compound(s) extracted from cinnamon potentiate insulin activity, as
measured by glucose oxidation in the rat epididymal fat cell assay. Wortmannin, a
potent PI 3'-kinase inhibitor, decreases the biological response to insulin and
bioactive compound(s) from cinnamon similarly, indicating that cinnamon is
affecting an element(s) upstream of PI 3'-kinase. Enzyme studies done in vitro
show that the bioactive compound(s) can stimulate autophosphorylation of a
truncated form of the insulin receptor and can inhibit PTP-1, a rat homolog of a
tyrosine phosphatase (PTP-1B) that inactivates the insulin receptor. No
inhibition was found with alkaline phosphate or calcineurin suggesting that the
active material is not a general phosphatase inhibitor. It is suggested, then,
that a cinnamon compound(s), like insulin, affects protein phosphorylation
dephosphorylation reactions in the intact adipocyte. Bioactive cinnamon compounds
may find further use in studies of insulin resistance in adult-onset diabetes.
PMID- 9762008
TI - Insulin-like growth factor I receptors are expressed by the enteroendocrine cell
line STC-1: relationship with proliferation and cholecystokinin expression.
AB - Receptors for insulin-like growth factors (IGF-I and IGF-II) are expressed in
mammalian intestinal epithelium. No information on the presence of IGF receptors
in intestinal endocrine cells is available. We tested for IGF-I receptors the
endocrine cell line STC-1, which synthesizes and processes cholecystokinin (CCK)
among other peptides, and assessed the effects of IGF-I on cell growth and CCK
content. Cell monolayers in serum-free culture medium specifically bound
[125I]IGF-I. Scatchard analysis was consistent with a single class of high
affinity binding sites (KD = 0.91 nM; Bmax = 4,700 sites/cell). In competitive
binding assays, unlabeled IGF-I, IGF-II and insulin displaced in a dose-dependent
manner [125I]IGF-I binding with the following potencies (KI): IGF-I (0.74 nM) >
IGF-II (3 nM) >> insulin (1 microM). Affinity cross-linking with [125I]IGF-I
using disuccinimidyl suberate and SDS-PAGE under reducing conditions yielded a
polypeptide band with apparent Mr 130,000, consistent with the alpha-subunit of
the IGF-I receptor. IGF-I and IGF-II (0.3-30 nM) dose-dependently stimulated
[3H]thymidine incorporation, with a maximal response of 110% above basal. IGF-II
was approximately 10-fold less potent than IGF-I, suggesting a mediation through
IGF-I receptors. In addition, the numbers of cells treated with 3 nM IGF-I
amounted to 116, 130 and 159% of control values after 1, 2 and 4 days of
incubation, respectively (p < 0.05). A significant increase in the cell CCK
contents was observed after a 48-hour exposure to 3 or 30 nM IGF-I. These results
demonstrate IGF-I receptor expression by the enteroendocrine cell line STC-1. IGF
I stimulates proliferation in short-term experiments, and increases intracellular
levels of CCK.
PMID- 9762009
TI - Hypergonadotropic hypogonadism in a 3-year-old girl with blepharophimosis,
ptosis, and epicanthus inversus syndrome.
AB - We report on ovarian dysfunction in a 3-year-old girl with blepharophimosis,
ptosis, and epicanthus inversus syndrome (BPES). A gonadotropin releasing hormone
test showed hyperresponses of luteinizing hormone (<0.2-->7.2 mIU/ml) and
follicle-stimulating hormone (7.1-->44.8 mIU/ml), and a human menopause
gonadotropin test yielded no estradiol response (13-->11 pg/ml). The results
suggest that primary ovarian failure in type I BPES can take place in early
childhood.
PMID- 9762010
TI - Hypothalamic-pituitary-adrenal axis suppression and inhaled corticosteroid
therapy. 1. General principles.
AB - The safety of long-term inhaled corticosteroid therapy at commonly prescribed
doses is an issue of growing concern to physicians and international regulatory
bodies. This is so because long-term use of these drugs has become the mainstay
of chronic asthma management and their introduction now is widely recommended in
official treatment guidelines at the 'mild persistent' stage of asthma, where
regular daily therapy is first begun. In addition to more frequent use of inhaled
corticosteroids, there is a further trend to use higher doses of existing inhaler
therapies and to use the newer and more potent compounds that have recently
become available. At the same time as these developments have been taking place,
there has not been a concurrent move to a more rigorous examination of the safety
profile of these inhaled corticosteroid treatments - especially to assess their
effects on the hypothalamic-pituitary-adrenal (HPA) axis. Most safety data with
respect to HPA axis effects have been derived from testing methods that are
limited in their ability to detect HPA system impairment and, more seriously,
that can give the impression of functional integrity in the HPA axis when there
may be moderate (or even greater) impairment. In this first part of a two-part
review of the HPA axis effects of inhaled corticosteroids and of how these
effects should be assessed, we examine the currently used and the currently
available testing methodologies and also review the present state of knowledge
concerning the structure and function of the HPA axis and the effects of its
suppression. It is clear that there are state-of-the-art tests to assess in a
discriminating manner the safety profile of inhaled corticosteroids. These tests
have been insufficiently employed, including during the drug development process,
yet they are readily available, relatively inexpensive and can detect adrenal
suppression before the appearance of clinical effects. In part 2 of this review
we examine what can be learned about the effects of inhaled corticosteroid
therapy on the HPA axis from the limited amount of reliable published information
from clinical and pharmacological studies describing their use and safety.
PMID- 9762011
TI - Hypothalamic-pituitary-adrenal axis suppression and inhaled corticosteroid
therapy. 2. Review of the literature.
AB - In the first part of this two-part review it was noted that inhaled
corticosteroids had become the mainstay of treatment for chronic asthma and yet
the effects of long-term use of these compounds on the hypothalamic-adrenal
pituitary (HPA) axis were largely being determined by testing methods of limited
reliability, especially by morning plasma cortisol measurements. It was
established in our examination of the published literature and in our
presentation of current knowledge of the structure and function of the HPA axis
that safe, accurate and discriminating techniques to assess the functional status
of the HPA axis were available. It was concluded that two state-of-the-art tests
that have been insufficiently used were the ACTH stimulation test and measurement
of the 24-hour integrated serial plasma cortisol concentrations. These two tests
can detect adrenal suppression before the appearance of clinical effects. For
part 2 of this review we conducted an exhaustive search of the English language
clinical and pharmacological literature on the use of inhaled corticosteroids
from 1988 until the present time to identify studies in which one or both of
these testing methods have been used. We present our analysis of this limited
number of studies to determine what accurately can be known of the HPA axis
safety profile of three of the most commonly used and investigated inhaled
corticosteroids - beclomethasone dipropionate, budesonide and fluticasone
propionate. The first finding of significance was that only 50 reports were
identified in which information on the HPA axis safety effects of orally inhaled
steroids in asthma patients or in clinical pharmacological studies met our
inclusion requirements. By analysis of the data presented in these reports we
were able to reach the following conclusions: (1) inhaled corticosteroids
administered chronically, and prudently, within recommended dose ranges do not
endanger the functioning of the HPA axis, (2) the increasing tendency to use
higher doses of inhaled corticosteroids on the assumption that there are clear
dose-response benefits and no adverse HPA axis effects from long-term high-dose
regimens is misguided and not supported by reliable published information, (3)
the corollary - that higher corticosteroid potencies (as measured, for example,
by skin-blanching activity) can have greater therapeutic effect in lung tissue
without greater concomitant systemic activity - is a flawed concept, and (4) the
limited clinical and pharmacological data support our part 1 conclusions that
discriminating techniques to assess the functional HPA axis status should be an
integral part of the drug development process and that further HPA axis function
studies are required on existing inhaled corticosteroids - if they lack a
rigorous testing history or long-term record of clinical safety.
PMID- 9762012
TI - Cellular signaling mechanisms for stimulation of growth hormone secretion and
growth hormone primary transcripts by immunosuppressant agents, FK506 and
cyclosporin A, in cultured rat pituitary cells.
AB - Although an immunosuppressant, FK506, has been known to stimulate growth hormone
(GH) release from rat somatotropes, the cellular signaling mechanism is unknown.
In the present study, intracellular signaling pathways were investigated for
FK506- and cyclosporin A (CsA)-induced GH release in cultured rat anterior
pituitary cells. Northern and Western blot analysis revealed that the FK506
binding protein (FKBP12) and the CsA-binding protein (cyclophilin A) exist at the
mRNA and protein level in the rat anterior pituitary tissue. FK506 and CsA
increased GH release in a dose-dependent manner and inhibited calcineurin (CaN)
activity in the cultured pituitary cells. The third immunosuppressant, rapamycin
(RP), inhibited the FK506-induced GH release, although RP alone had no effect.
Protein kinase A (PKA) inhibitors, H-89 and HA-1004 and EGTA blocked FK506- and
CsA-induced GH release. TGF-beta did not alter basal GH release, but inhibited
FK506-induced GH release. GH primary transcripts were increased by FK506, and the
effects were blocked by H-89 and HA-1004. These results suggest that the
immunosuppressants, FK506 and CsA, stimulate GH release by inhibiting CaN
activity which results in the activation of the PKA system in the rat
somatotropes. TGF-beta receptors might be involved in FK506-induced GH release as
a separate pathway. FK506 also stimulates GH primary transcripts via a PKA
dependent mechanism in a manner similar to its effects on GH release.
PMID- 9762013
TI - Effects of a long-term inhalation of fragrances on the stress-induced
immunosuppression in mice.
AB - The aim of this study was to determine the effects of the long-term application
of various fragrances on the suppression of immune response induced by high
pressure stress in mice. The immune response was analyzed based on plaque-forming
cell (PFC) count, using mice sensitized with sheep red blood cells. The decreased
PFC involving thymic involution induced by high-pressure stress in mice was
restored by exposing the stressed mice to tuberose, lemon, oakmoss and labdanum
for 24 h following exposure to stress. The decreased PFC and thymic involution
from stress were restored by exposure to lemon and oakmoss, but not to tuberose
and labdanum when the mice were exposed to those fragrances continuously for 3
weeks before the stress was given, followed by exposure to the same fragrances
for 24 h after the stress. The decreased PFC and thymic involution from stress
were restored by exposure to lemon and labdanum for 24 h after the stress, but
not to tuberose over 3 weeks before the stress was given. These data suggest that
the neuroimmunomodulatory effects of fragrances may be affected by tolerance
depending on the kinds of fragrances in the case of a long-term application.
PMID- 9762014
TI - The restraint stress-induced elevation in plasma interleukin-6 negatively
regulates the plasma TNF-alpha level.
AB - Although a considerable amount of evidence has shown that physical and
psychological stress elevates the plasma interleukin 6 (IL-6) levels, the
physiological significance of such an elevation remains to be elucidated. In this
study, in order to determine whether the restraint stress-induced elevation of
plasma IL-6 contributes to the activation of the hypothalamic-pituitary-adrenal
axis, and whether or not such elevation can affect the inflammatory processes,
the plasma levels of ACTH, corticosterone, interleukin-1 (IL-1), and tumor
necrosis factor-alpha (TNF-alpha) in mice pretreated with anti-IL-6 antibody (MP5
20F3 monoclonal antibody) were compared with those in mice pretreated with rat
IgG (control antibody) both during and after stress. Both the anti-IL-6-antibody-
and control-antibody-pretreated mice showed the same extent of plasma ACTH and
corticosterone increases during stress, and no significant difference was found
between the two groups of animals. On the other hand, the level of plasma TNF
alpha in the anti-IL-6-treated animals was also significantly higher than that in
the control animals both immediately after cessation of stress and 60 min after
the cessation of the 120-min period of restraint. Plasma IL-1 activity, however,
did not reach a detectable level in either group of animals at any time point
examined. These results thus indicate that the restraint-stress-induced elevation
of plasma IL-6 negatively regulates the plasma TNF-alpha levels and may thus
contribute to the maintenance of homeostasis.
PMID- 9762015
TI - Repeated in vivo hydrocortisone treatment promotes a dual modulation of
cytokeratin expression by mouse thymic epithelial cells.
AB - Previous studies showed that a single dose of hydrocortisone in mice was able to
transiently upregulate the expression of cytokeratins (CKs) 3 and 10 by medullary
epithelial cells of the mouse thymus. Herein we studied these cells (specifically
recognized by immunocytochemistry with the anti-CK monoclonal antibody KL1)
following a series of repeated injections of the glucocorticoid hormone. A
progressive dual (up and down) modulation of KL1+ medullary epithelial cells was
observed with a late appearance of KL1 immunoreactivity in the thymic cortex. The
data indicate that a single versus repeated exposure to high doses of
glucocorticoid hormone may trigger different circuits regulating intrathymic CK
expression. Lastly, the model described herein may be regarded as promising in
studies concerning the effect of repeated stress conditions upon the thymus.
PMID- 9762016
TI - Nicotine for pyoderma gangrenosum.
PMID- 9762017
TI - Evaluation of clinical criteria for diagnosis of bullous pemphigoid. French
Bullous Study Group.
AB - OBJECTIVE: To check the potential usefulness of clinical criteria for the
diagnosis of bullous pemphigoid when state-of-the-art techniques such as Western
immunoblotting, immunoprecipitation, and indirect immunofluorescence on salt
split skin or direct immunoelectron microscopy are not available. DESIGN:
Comparison of the clinical criteria between 2 groups (with and without bullous
pemphigoid) as defined by immunoelectron microscopy used as standard criterion,
in a prospective study. Multivariate logistic regression analysis was carried out
by including all items that were statistically significant (at P < .05 level) in
univariate analysis. SETTING: Five dermatology departments in teaching hospitals.
PATIENTS: The 231 patients studied had subepidermal autoimmune bullous diseases
with linear IgG or C3 deposits in the basement membrane zone (157 with bullous
pemphigoid, 33 with cicatricial pemphigoid, 30 with epidermolysis bullous
acquisita, 5 with lupus erythematosus, and 6 others). A second set of patients
was used to calculate predictive values. RESULTS: The multivariate logistic
stepwise analysis resulted in a final set of predictors that included only 4
items: absence of atrophic scars, absence of head and neck involvement, absence
of mucosal involvement, and age greater than 70 years. No additional variables
met the .05 significance level to enter into the model. If 3 of these 4
characteristics were present, a diagnosis of bullous pemphigoid could be made
with a sensitivity of 90% and a specificity of 83%; these predictive values were
calculated on a sample of 70 new cases. CONCLUSIONS: With and estimated incidence
of bullous pemphigoid among subepidermal autoimmune bullous diseases of 80%, the
presence of 3 of the 4 significant criteria allows the diagnosis of bullous
pemphigoid, with a positive predictive value of 95%. Our set of clinical criteria
thus allows the diagnosis of bullous pemphigoid with good validity for both
clinical practice and therapeutic trials.
PMID- 9762018
TI - Disease associations in polymorphous light eruption. A long-term follow-up study
of 94 patients.
AB - OBJECTIVES: To examine the long-term outcome of polymorphous light eruption (PLE)
in a large patient population and to evaluate associated conditions, especially
lupus erythematosus, during the course of the disease. DESIGN: A questionnaire
based follow-up study an average of 32 years after onset of PLE. The study was
complemented by clinical examination of the patients with PLE similarly studied
16 years earlier or now reporting equal or worse PLE symptoms compared with the
1978-1979 follow-up or any symptoms suggesting an autoimmune disease. SETTING: A
dermatologic clinic in a university hospital. PATIENTS: Ninety-four of the
original cohort of 138 patients with PLE (87% of living patients) returned the
questionnaire, and 46 (84%) of the 55 patients invited volunteered for clinical
examination. INTERVENTION: None. MAIN OUTCOME MEASURES: Clinical characteristics
of PLE and clinical laboratory findings referring to associated diseases,
especially lupus erythematosus. RESULTS: Twenty-three (24%; 95% confidence
interval [CI], 16%-34%) of the 94 patients were cured, 48 (51%; 95% CI, 41%-62%)
experienced milder symptoms, and 23 (24%; 95% CI, 16%-34%) experienced equal or
worse symptoms than in the 1978-1979 follow-up. At least 1 autoimmune disease was
diagnosed at some point in 14 patients (15%; 95% CI, 12%-29%) (in 13 [18%] of the
female patients) and lupus erythematosus specifically in 2 (2%; 95% CI, 0%-7%)
(in 2 [3] of the female patients). The prevalence of a thyroid disease was 14%
(13 patients) (95% CI, 8%-23%). CONCLUSION: Polymorphous light eruption is a long
standing slowly ameliorating disease with some tendency to development of
autoimmune disease or thyroid disorder, especially in female patients, but the
risk for lupus erythematosus is not increased.
PMID- 9762019
TI - Managed care and the treatment of skin disease, 1995. Continued growth and
emerging dominance.
AB - OBJECTIVE: To document changes in type of financing for office-based visits for
the treatment of common skin conditions and to dermatologists. DESIGN: Data from
a national survey of visits to office-based practitioners conducted by the
National Center for Health Statistics were used. The stratified sampling
technique permits estimation of the total number of office visits with specific
characteristics in the United States. SETTING: A national probability sample of
visits to office-based practitioners occurring in 1995. SUBJECTS: In 1995, 36,875
visits were sampled. Of these, 2121 were for common skin problems to any
physician and 1886 were visits for any reason to dermatologists. MAIN OUTCOME
MEASURES: The distribution source of payment and presence of managed care
arrangements for office visits for common skin problems and to dermatologists.
INTERVENTION: None. RESULTS: In 1995, preferred provider and health maintenance
organizations provided payment for 34% of all ambulatory care and 38% of office
visits for common skin complaints. CONCLUSION: Managed care is already the
dominant mechanism of payment for the treatment of skin disease for many patient
groups and in many areas of the country. Preferred provider organizations are
much more likely to employ dermatologists to provide care of common skin problems
than are health maintenance organizations. If the recent trends continue, by year
2000 most patients seen by dermatologists will be seen under the auspices of
managed care systems.
PMID- 9762021
TI - Topical tacrolimus is not effective in chronic plaque psoriasis. A pilot study.
AB - BACKGROUND: Cyclosporine for the treatment of psoriasis constitutes a new
approach. Alternative systemic cyclosporine derivatives have been studied to find
an immunosuppressive drug with fewer adverse effects. Tacrolimus is one of these
new immunosuppressive drugs. Systematically, it has been proven effective in
treating psoriasis. A topical formulation of tacrolimus is attractive because it
has fewer adverse effects and is useful for a large group of patients. We report
for the first time on the efficacy of nonocclusive topical tacrolimus in the
treatment of psoriasis. OBSERVATIONS: After a washout phase of 2 weeks, patients
were randomized to receive 0.005% calcipotriol ointment twice daily, placebo
ointment once daily, or 0.3% tacrolimus ointment once daily. One psoriatic plaque
was treated with a surface area of 40 to 200 cm2. Efficacy was estimated using
the local psoriasis severity index. The reduction in the local psoriasis severity
index score after 6 weeks was 62.5% in the calcipotriol group, 33.3% in the
tacrolimus group, and 42.9% in the placebo group. CONCLUSIONS: There was no
statistically significant difference between the efficacy of tacrolimus and
placebo ointment (P = .77). Calcipotriol ointment, applied twice daily, had a
better effect than tacrolimus ointment and placebo ointment once daily.
PMID- 9762020
TI - Reports by patients and dermatologists of skin cancer preventive services
provided in dermatology offices.
AB - OBJECTIVE: To learn how often patients receive skin cancer preventive services in
dermatologists' offices. DESIGN: Survey of dermatology patients and
dermatologists. SETTING: Dermatology practices of full-and part-time faculty at a
midwestern medical school. PARTICIPANTS: Patients were randomly selected from
clinical sessions of 11 dermatologists. Of 200 patients enrolled, 162 (81%)
responded to the survey. Ten (91%) of the dermatologists responded, and 4
additional dermatologists from the faculty were also surveyed. MAIN OUTCOME
MEASURES: Patients' and dermatologists' reports of the provision of skin cancer
prevention counseling and screening for skin cancer. RESULTS: Most patients (93%)
had been informed about the risks of sun exposure, but for only 27% was a
dermatologist the main source of information. Although 76% of patients had seen a
dermatologist at least twice in the last 5 years, only 34% reported that they had
ever received a total-body screening examination for skin cancer. Most patients
(55%) would like to learn more about skin cancer prevention, and responded that
they would learn best from a brochure (43%) or from a dermatologist (42%). All
dermatologists believed that some skin cancer preventive services should be
provided to each patient, but they varied widely in the proportion of their white
adult patients to whom they provided such services. For example, with respect to
counseling about sunscreens, the same number of dermatologists (4 [29%])
responded that they counsel 25% or less of their patients, and more than 75% of
their patients. CONCLUSION: There is wide variation in how often skin cancer
preventive services are provided in dermatologists' offices.
PMID- 9762022
TI - Treatment of pemphigus with gold.
AB - BACKGROUND: Although gold has been reported to be useful in treating pemphigus
vulgaris, its use has waned in recent years because of concerns regarding
efficacy and toxicity. OBJECTIVE: To review 26 patients with pemphigus who were
treated with intramuscular gold over a 10-year period. RESULTS: Gold was
effective in 62% of patients as a primary treatment for pemphigus or as a steroid
sparing agent. An average of 3 months of therapy was required before the daily
prednisone dosage could be halved. Four patients were free of disease and stopped
receiving all therapy at the conclusion of the study. Toxic effects due to gold
therapy developed in 42% of patients and all adverse effects resolved with its
cessation. CONCLUSIONS: While toxic effects limit the use of gold in many
patients with pemphigus, it may be effective in treating a large percentage of
patients who otherwise are unable to reduce their steroid requirement. Because of
its delayed onset of action, patients treated with gold usually require systemic
steroids when therapy is initiated. Controlled, prospective trials are needed to
further evaluate the efficacy of gold and its potential steroid-sparing effects.
PMID- 9762023
TI - Human herpesvirus 6 infection as a risk factor for the development of severe drug
induced hypersensitivity syndrome.
AB - BACKGROUND: Drug-induced hypersensitivity syndrome is characterized by a severe,
potentially fatal, multiorgan hypersensitivity reaction that usually appears
after prolonged exposure to certain drugs. Its delayed onset and clinical
resemblance to infectious mononucleosis suggest that underlying viral infections
may trigger and activate the disease in susceptible individuals receiving these
drugs. OBSERVATIONS: A 60-year-old woman developed an itchy, generalized,
erythematous, confluent rash on the 39th day of receiving allopurinol therapy.
Even after she discontinued treatment with allopurinol, her skin lesions
progressed to severe blistering skin eruption. After the patient started oral
prednisone therapy, her skin lesions resolved with desquamation. After complete
resolution, rechallenge with allopurinol led to the development of an
erythematous eruption. Titers of human herpesvirus 6 IgG antibodies dramatically
increased with the development of the eruption. The results of a polymerase chain
reaction and in situ hybridization indicated the presence of human herpesvirus 6
in the skin lesions, although human herpesvirus 7 DNA was detected only by in
situ hybridization. CONCLUSION: Reactivation of human herpesvirus 6, possibly in
concert with human herpesvirus 7, can contribute to the development of a severe
drug-induced hypersensitivity syndrome.
PMID- 9762024
TI - Severe hypersensitivity syndrome due to sulfasalazine associated with
reactivation of human herpesvirus 6.
AB - BACKGROUND: A severe adverse reaction to sulfasalazine therapy has been
associated with hypersensitivity syndrome, the clinical features of which are
similar to infectious mononucleosis. No serologic evidence of viral infections
has been reported with this syndrome; however, human herpesvirus 6 infection has
not been specifically investigated, which could cause an infectious
mononucleosislike syndrome. OBSERVATIONS: We report 2 cases of hypersensitivity
syndrome induced by the use of sulfasalazine. The clinical features of the
syndrome appeared 18 and 32 days after administration of sulfasalazine. Clinical
signs included a maculopapular rash progressing to exfoliate erythroderma, fever,
and lymphadenopathy. Leukocytosis, atypical lymphocytes, liver dysfunction, and
renal disturbance were also observed. In 1 patient, human herpesvirus 6 variant B
was isolated from peripheral blood mononuclear cells, and in both patients anti
human herpesvirus 6 IgG titers increased considerably. CONCLUSIONS: Two cases of
hypersensitivity syndrome due to sulfasalazine use were associated with the
reactivation of human herpesvirus 6, which may be a required cause of
hypersensitivity syndrome.
PMID- 9762025
TI - Infantile pyramidal protrusion as a manifestation of lichen sclerosus et
atrophicus.
AB - BACKGROUND: A perineal infantile lesion previously described as "skin tag/fold"
had recently been named infantile perianal pyramidal protrusion. It appears on
the perineal median raphe of girls as a pyramidal soft tissue swelling, covered
by smooth, red or rose-colored skin. Its pathogenesis is unknown. As in the case
of other perianal lesions, knowledge about it is important, as concern about
signs of child abuse grows. OBSERVATIONS: Four girls, 2 of them sisters, with
infantile perianal pyramidal protrusion were studied. Three of these girls showed
subtle clinical evidence of classic lichen sclerosus et atrophicus on first
examination. The other girl developed vulvar lesions of lichen sclerosus et
atrophicus months after the diagnosis of infantile perianal pyramidal protrusion.
All 4 protrusions disclosed histopathological findings diagnostic of lichen
sclerosus et atrophicus. CONCLUSIONS: Infantile perianal pyramidal protrusion is,
at least in some patients, a peculiar form of lichen sclerosus et atrophicus that
can precede other, more characteristic manifestations. We suggest changing the
name to the more precise infantile perineal protrusion. Knowledge of this
hitherto unrecognized clinical form of lichen sclerosus et atrophicus can help to
explain anogenital symptoms and avoid its misinterpretation as a sign of sexual
abuse.
PMID- 9762026
TI - Congenital cutaneous defects as complications in surviving co-twins. Aplasia
cutis congenita and neonatal volkmann ischemic contracture of the forearm.
AB - BACKGROUND: During twin pregnancies, several complications may result in the
death of a co-twin depending on the date of death. We describe herein 2 infant
survivors of monozygotic twin pairs with 2 distinct possible complications: a
aplasia cutis congenita and Volkmann ischemic contracture. OBSERVATIONS: One
infant had extensive aplasia cutis congenita with an associated monozygotic co
twin who died at 3 months of gestation, and the other child had a localized arm
defect due to Volkmann ischemic contracture and brain damage, with a co-twin who
died at approximately 6 weeks of gestation. CONCLUSIONS: Congenital cutaneous
defects may result in the death of a co-twin. The most common of these defects is
aplasia cutis congenita associated with a fetus papyraceus or a dead fetus
related to ischemic/thrombotic events in the placenta and fetus. Volkmann
ischemic contracture is rare in the newborn but can cause neonatal cutaneous
defects. The cause of Volkmann ischemic contracture in newborns is unknown;
however, our second observation suggests the possible role of a dead fetus.
PMID- 9762027
TI - Waldenstrom macroglobulinemia-induced bullous dermatosis.
AB - BACKGROUND: Waldenstrom macroglobulinemia is a plasma cell dyscrasia of
undetermined cause characterized by the monoclonal proliferation of
lymphoplasmacytes in the bone marrow, lymph nodes, and spleen and elevated
circulating levels and tissue deposition of monoclonal IgM produced by these
aberrant cells. Rarely, cutaneous manifestations of this disease have been
reported. OBSERVATIONS: We report the case of a patient with bullous dermatosis
induced by Waldenstrom macroglobulinemia and demonstrate the subepidermal
location of the separation and the presence of IgM and kappa light chains by
immunoperoxidase, immunofluorescent techniques, and electron microscopy with
immunogold staining. Immunoblotting revealed a strong band at the 290-kd area.
CONCLUSIONS: The demonstration of the separation in the upper dermis at the site
of IgM deposits suggests that these deposits may be an etiologic factor in this
rare manifestation.
PMID- 9762028
TI - Bullous pemphigoid. The latest in diagnosis, prognosis, and therapy.
PMID- 9762029
TI - Chronic plaques in a patient with ataxia telangiectasia. Cutaneous granulomatous
lesions in a patient with AT.
PMID- 9762030
TI - Tumor of the right shoulder in a newborn. Bossed hemangioma with telangiectasia
and peripheral pallor.
PMID- 9762031
TI - Skin ulcers associated with a tender and swollen arm. Pyoderma gangrenosum (PG)
in association with chronic recurrent multifocal osteomyelitis (CRMO).
PMID- 9762032
TI - Perianal dermatitis in a child. Perianal streptococcal dermatitis (PSD).
PMID- 9762034
TI - Human herpesviruses 6 and 7. New roles yet to be discovered?
PMID- 9762033
TI - Do we have time for the change?
PMID- 9762035
TI - Mergers, separations, and transformations of dermatology residency training
programs: a resident's perspective.
PMID- 9762036
TI - Don't dispense with dispensing.
PMID- 9762037
TI - Who should care for hospitalized patients with severe skin disease?
PMID- 9762038
TI - The proper future for medical dermatology.
PMID- 9762039
TI - Declining interest in medical dermatology.
PMID- 9762040
TI - No evidence of HHV-8 infection in patients with pemphigus vulgaris/foliaceus.
PMID- 9762041
TI - Adverse effects of spironolactone therapy in women with acne.
PMID- 9762042
TI - Anaphylaxis to intradermal triamcinolone acetonide.
PMID- 9762043
TI - Alopecia areata has low plasma levels of the vasodilator/immunomodulator
calcitonin gene-related peptide.
PMID- 9762044
TI - Helicobacter pylori eradication in patients with chronic urticaria.
PMID- 9762045
TI - Nail bed dyschromia secondary to docetaxel therapy.
PMID- 9762046
TI - Unilateral abdominal distention following herpes zoster outbreak.
PMID- 9762047
TI - Treatment of acyclovir-resistant, foscarnet-unresponsive HSV infection with
topical cidofovir in a child with AIDS.
PMID- 9762048
TI - Genetic analysis of a trichoepithelioma and associated basal cell carcinoma.
PMID- 9762049
TI - [Vena cava umbrella filter: complications and treatment].
AB - BACKGROUND AND OBJECTIVE: Increasing numbers of vena canal filters are being
implanted to prevent pulmonary embolism, which are mainly the consequence of deep
vein and pelvic vein thrombosis. Can a filter be removed again in case of
complications arising from it? What is the risk of such operative explantation?
What is the subsequent risk of pulmonary embolism? PATIENTS AND METHODS: In nine
patients (5 males, 4 females; mean age 45 (30-39 years) who had vena caval
filters implanted because of thromboembolism despite anticoagulation,
complications due to the filter required its operative removal and thrombectomy
of the large veins 3 days to 48 months after implantation in the inferior vena
cava (IVC). One inguinal arteriovenous fistula (due to perforation of rods of a
displaced filter) were closed. The patients' case note were retrospectively
analysed and eight of the nine patients' were reexamined according to a
standardized procedure a mean of 20 months after removal of the filter. RESULTS:
Explantation of the filter had been successful in all patients. But there were
two nonfatal postoperative complications: a pulmonary embolus and a paradoxical
cerebral embolus. In one patient a segmental stenosis of the IVC with
retroperitoneal collateral circulation was found at operation. All but one of 16
pelvic veins that had thrombectomies performed at the time of filter explanation
were patent, as were the IVCs in seven of the eight re-examined patients. None of
the patients had evidence of postoperative pulmonary embolism. CONCLUSIONS: Vena
caval filters can be explanted with a low operative risk. After removal and
venous thrombectomy, implantation of another caval filter is unnecessary. As
anticoagulation properly monitored is almost always an effective measure in the
prevention of pulmonary thromboembolism, filter implantation should be performed
only on the strictest indication, as an ultimate step.
PMID- 9762050
TI - [Anal gland carcinoma with osteoblastic metastases].
AB - HISTORY AND CLINICALLY FINDINGS: A 52-year-old woman was admitted because of anal
pain of 6 weeks duration. Physical examination was unremarkable except for a
cherry-sized swelling, painful to pressure, on rectal examination. As the
erythrocyte sedimentation rate and C-reactive protein were increased (69/115 and
12.1 mg/dl, respectively) and abscess was diagnosed. Carcinoembryonic antigen was
within normal limits. INVESTIGATIONS: At rectoscopy a fluctuating abscess-linked
swelling was found at 3 cm and a submucous tumour at 5 cm from the anus.
TREATMENT AND COURSE: The abscess was cut open and at the level of the dentate
line a submucous adenocarcinoma about 3 cm in diameter was resected. A small
residual tumour was removed by abdomino-perineal rectal extirpation. As
histologically it was an adenocarcinoma not of colorectal type, without
relationship to rectal mucosa but in close contact to the anal glands, and the
further course did not indicate a metastasis from another primary tumour, the
diagnosis of anal gland adenocarcinoma was established. A local recurrency was
resected 6 months later, followed by combined radio- and chemotherapy. A diffuse
osteoblastic metastasis was discovered later and the patient died 21 months after
diagnosis. CONCLUSION: An osteoblastic metastasis from an anal gland carcinoma,
as occurred in this case, has not been previously reported.
PMID- 9762051
TI - [Primary varices of the colon. A rare cause of gastrointestinal bleeding].
AB - HISTORY: A 34-year-old patient presented with a two-day history of passing bright
red blood with his stools. There was no contributory past or family history and
he had no accompanying symptoms. INVESTIGATIONS: Colonoscopy revealed many
varices in the colon and terminal ileum without an active source of bleeding.
Angiography failed to demonstrate any bleeding or vascular anomaly in the
splanchnic region. Abdominal ultrasound and gastroscopy as well as biochemical
tests did not indicate portal hypertension or liver cirrhosis. TREATMENT AND
COURSE: On the night of admission there was a renewed fall in haemoglobin
concentration. Emergency colonoscopy again failed to discover a source of
bleeding. After transfusion of four units of erythrocyte concentrate the further
course was uneventful. 8 months and 3 years later there were further episodes of
marked bleeding per rectum. At the latest admission no source for the bleeding
was found but there was some blood oozing in the sigmoid colon. Biochemical tests
were unremarkable. The large varices were again seen in the colon and terminal
ileum. Gastroscopy, Doppler sonography of the liver and repeat abdominal
sonography again failed to demonstrate portal vein thrombosis, liver cirrhosis or
portal hypertension. CONCLUSION: In case of colonic varices the differential
diagnosis should include portal hypertension with chronic liver disease, portal
vein thrombosis, vascular anomalies or postoperative complications. The treatment
of primary varices, which are rare, is conservative.
PMID- 9762052
TI - [Diagnosis of extracranial carotid stenosis].
PMID- 9762053
TI - [Left heart assist device or heart transplantation? New strategies for the
treatment of terminal heart insufficiency].
PMID- 9762054
TI - [Danger for exposure of waste collection and removal workers to infectious
agents].
PMID- 9762055
TI - Oral anticoagulants.
PMID- 9762056
TI - Attention deficit hyperactivity disorder: focus on genetics.
PMID- 9762057
TI - Restructuring hospital services.
PMID- 9762058
TI - Peer review on the Internet: launching eMJA peer review study 2.
PMID- 9762059
TI - Paediatric rotavirus gastroenteritis: where to now in prevention and treatment?
PMID- 9762060
TI - Effectiveness of anticoagulation among patients discharged from hospital on
warfarin. The Newcastle Anticoagulation Study Group.
AB - OBJECTIVES: To examine the effectiveness of anticoagulation among patients
discharged from hospital on warfarin in the care of general practitioners (GPs).
DESIGN AND SETTING: A historical cohort with questionnaires to patients
discharged from a major metropolitan teaching hospital and their GPs.
PARTICIPANTS: Patients discharged between 1 February 1995 and 31 January 1996
identified from hospital pharmacy records as being prescribed warfarin, and their
treating GPs. MAIN OUTCOME MEASURES: Frequency of testing and levels of
international normalised ratio of prothrombin time (INR) within six months of
discharge; level of INR aimed at by GP; complication rates; and patient knowledge
about anticoagulation. RESULTS: Replies were received from 242 (68%) patients and
pathology records were examined for 195 (81%) of these. The median gap between
INR measures was seven days. The median of the median INR level for each patient
was 2.4 (rising to 2.7 in patients with an artificial heart valve); 24% of
observed patient time was spent at an INR level of less than 2.0, 54% between 2.0
and 2.9, 18% between 3.0 and 3.9 and 4% at an INR level of 4.0 or more. There
were five confirmed major complications (equivalent to 5 per 100 patient-years).
Twenty-seven per cent of patients answered at least eight of the 10 knowledge
questions correctly: education level predicted knowledge, but there was no
relationship between knowledge and INR level. CONCLUSIONS: Among this unselected
group of patients whose anticoagulation was managed by GPs, there was a high
frequency of laboratory testing. INR levels were controlled safely and
complication rates were comparable with those in published reports.
PMID- 9762061
TI - Re-engineering the elective surgical service of a tertiary hospital: a historical
controlled trial.
AB - OBJECTIVE: To study the clinical effects of re-engineering the processes
associated with elective surgery. DESIGN: A prospective, historical controlled
trial. Control patients were enrolled from March 1995 to January 1996, and
postintervention patients from February 1996 to October 1996. SETTING: A major
teaching, tertiary care hospital (Prince of Wales Hospital, Sydney). PATIENTS:
224 patients (123 before and 101 after the intervention) undergoing elective
herniorrhaphy of laparoscopic cholecystectomy who lived in the local area.
INTERVENTION: Introduction of a re-engineered surgical service consisting of
preadmission assessment and education, admission on day of surgery, and postacute
care after discharge. There were no changes to the operative methods or infection
control procedures. MAIN OUTCOME MEASURES: Length of stay, operative
complications, pain scores and patient satisfaction. RESULTS: The risk of a
patient suffering one or more complications was reduced in the postintervention
group (postintervention v. control patients: 25.7% v. 38.2%; relative risk [RR],
0.66; 95% confidence interval [CI], 0.44-0.98; P = 0.035) because of a reduced
risk of wound infections (5.0% v. 16.3%; RR, 0.30; 95% CI, 0.12-0.78; P =
0.0075). Other complications (perioperative or postoperative) and pain scores
were unchanged. Patients treated by the re-engineered service had a significantly
shorter length of stay, reported a higher level of satisfaction with the
preoperative and postdischarge care, and were more likely to say that they would
have the same treatment again (92.9% v 82.6%; P = 0.037). CONCLUSIONS: Re
engineering surgical services, with an associated reduction in length of stay,
does not lead to a deterioration in care and may decrease postoperative
complications and increase patient satisfaction.
PMID- 9762062
TI - Rotavirus infection and rates of hospitalisation for acute gastroenteritis in
young children in Australia, 1993-1996.
AB - OBJECTIVE: To determine rates of hospitalisation of young children for acute
gastroenteritis in Australia, and to estimate the proportion of these admissions
caused by rotavirus infection. DESIGN: Analysis of hospital admission records,
and parallel, prospectively collected data on rotavirus-positive admissions.
SETTING: Hospitals admitting young children in all Australian States and
Territories in 1993-1996. PATIENTS: All children under five years admitted to
hospital for acute gastroenteritis (International Classification of Diseases,
ninth revision principal diagnosis codes 003.0, 004.0-009.3 and 558.9). MAIN
OUTCOME MEASURES: Rate of hospital admission per 1000 children per year by State,
and the proportion of admissions caused by rotavirus infection. RESULTS: There
were almost 20,000 hospital admissions annually in Australia for acute
gastroenteritis in children under five years, at an average rate of 15/1000. An
estimated 50% of these were attributable to rotavirus infection, implying a rate
of hospitalisation for rotavirus-related gastroenteritis of 7.5/1000/year. Among
children under two years this rate was 11.6/1000. Rotavirus incidence rates
generally followed a typical seasonal pattern in temperate regions of the
country, with sharp peaks in mid to late winter. Rates of hospitalisation varied
markedly, even between States with apparently similar patterns of disease, while
the incidence in the Northern Territory was 3-5 times higher than other States.
CONCLUSIONS: Rotavirus-related gastroenteritis is a major cause of hospital
admissions in young children, and large savings to the healthcare system are
possible if it can be prevented at reasonable cost. Variation in treatment
practices between States may be worth studying in greater detail as another
source of potential savings.
PMID- 9762063
TI - A life-threatening anaphylactoid reaction to polyvalent snake antivenom despite
pretreatment.
AB - A 44-year-old man suffered a life-threatening anaphylactoid reaction to
polyvalent snake antivenom, although he had been given the recommended
pretreatment. Further research is needed to determine if pretreatment is
necessary.
PMID- 9762065
TI - "Pharmaceutical security": a new research agenda?
PMID- 9762064
TI - Systematic review of Propionibacterium acnes resistance to systemic antibiotics.
AB - OBJECTIVE: To document changes in the prevalence of resistance of
Propionibacterium acnes to antibiotics used for treating acne. DATA SOURCES:
MEDLINE and EMBASE were searched for publications on P. acnes resistance to
systemic antibiotics. The search strategy mapped "acne" or "acne vulgaris" with
the terms "antibiotic resistance" or "drug resistance, microbial". Only papers
published in English during 1976 to 1997 were included in the search. STUDY
SELECTION: 53 publications met the search criteria. The search output was refined
by selecting papers that specifically addressed P. acnes resistance patterns.
Additional studies (not included in the search output) were identified from
review articles and references of the retrieved articles. Twelve articles were
reviewed. DATA EXTRACTION: Data on the prevalence of antibiotic-resistant
propionibacteria, the incidence of individual resistance phenotypes, mixed
resistance, and correlation between poor therapeutic response and resistant
propionibacteria were extracted. DATA SYNTHESIS: Research since 1978 has
suggested an association between poor therapeutic response and antibiotic
resistant propionibacteria. The overall incidence of P. acnes antibiotic
resistance has increased from 20% in 1978 to 62% in 1996. Resistance to specific
antibiotics varied and was most commonly reported with erythromycin and
clindamycin, tetracycline and doxcycline, and trimethoprim. Resistance to
minocycline is rare. CONCLUSIONS: In many patients with acne, continued treatment
with antibiotics can be inappropriate or ineffective. It is important to
recognise therapeutic failure and alter treatment accordingly. The use of long
term rotational antibiotics is outdated and will only exacerbate antibiotic
resistance.
PMID- 9762066
TI - Magnetic resonance cholangiopancreatography: non-invasive imaging for the biliary
tree and pancreatic duct.
AB - Producing images similar to those acquired by the invasive procedures of
endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous
transhepatic cholangiography, magnetic resonance cholangiopancreatography (MRCP)
is indicated in patients who are unable to undergo ERCP or have had previously
unsuccessful ERCP. It is used increasingly in non-invasive evaluation of the
pancreaticobiliary tree in cases where the need for intervention during ERCP is
expected to be low. MRCP may help in identifying anomalous biliary anatomy or
choledocholithiasis before laparoscopic cholecystectomy, and in deciding between
percutaneous or endoscopic treatment for patients with obstructive jaundice to
decrease the rate of failed ERCP procedures.
PMID- 9762067
TI - Premature closure of the fetal ductus arteriosus after maternal use of non
steroidal anti-inflammatory drugs. Adverse Drug Reactions Advisory Committee.
PMID- 9762068
TI - Irritable bowel syndrome.
PMID- 9762069
TI - Hazards of hot water use for plaster of Paris slabs.
PMID- 9762070
TI - Should there be an accredited ethics committee system for centralised review of
multicentre clinical research?
PMID- 9762071
TI - Should there be an accredited ethics committee system for centralised review of
multicentre clinical research?
PMID- 9762072
TI - Should there be an accredited ethics committee system for centralised review of
multicentre clinical research?
PMID- 9762073
TI - Should there be an accredited ethics committee system for centralised review of
multicentre clinical research?
PMID- 9762074
TI - Prescription use by patients with concession cards.
PMID- 9762075
TI - General internal medicine in Australia and New Zealand--a renaissance.
PMID- 9762076
TI - Infant pertussis deaths in New South Wales 1996-1997.
PMID- 9762077
TI - Sporotrichosis in a Queensland bushwalker.
PMID- 9762078
TI - "Fisting" as a cause of vaginal bleeding.
PMID- 9762080
TI - Circular dichroic analysis of protein conformation: inclusion of the beta-turns.
AB - The mean residue ellipticity, [theta], at any wavelength, lambda, of a protein in
aqueous solution is expressed as [theta]lambda = fH[theta]H infinity(1-k/n) + f
beta[theta]beta + ft[theta]t + fR[theta]R with two constraints: 1 > or = fj > or
= 0 and sigma fj = 1. The subscripts H, beta, t, and R refer to the helix, beta
form, beta-turn, and unordered form. The fractions, fj's, of 15 proteins are
based on X-ray crystallography, ft refers to the net beta-turn after cancelling
those residues having dihedral angles of opposite sign. The [theta]H infinity of
an infinite helix and its chain-length dependence factor, k, were computed from
the myoglobin data (Chen et al., 1974, Biochemistry 13, 3350). The average number
of residues per helical segment, n, for 15 proteins was about 10, which can be
used for proteins of unknown structure. The reference spectra of other three
structural elements are computed by a least-squares method. Once the reference
spectra are chosen, the same equation above can be used to estimate the fractions
of the secondary structure of a protein from its CD data points between 190 and
240 nm at 1-nm intervals. The computed helical content is usually good to
excellent (concanavalin A is a notable exception). Inclusion of the beta-turn in
the analysis improves the correlation for the estimates of the beta-form, but the
computed beta t values are not significantly correlated with the X-ray results.
Matrix formulation proves the equivalence of the least-squares method and the
integral curve-fitting.
PMID- 9762079
TI - Preparative gel electrophoresis: detection, excision, and elution of protein
bands from unstained gels.
AB - Methods are described for localizing proteins in unstained gels and accurately
excising the regions containing them. A gel elutor, which is all glass with
Lucite fittings, is also described. The elutor removes proteins from gels with a
high yield and concentrates the protein in a small volume. The elutor is simple
and very easy to use. A way is presented for avoiding the oxidation of methionine
and cysteine during preparative electrophoresis.
PMID- 9762081
TI - A new method to characterize saturation functions by their first four moments.
AB - The calculation of the first four moments of saturation functions is proposed as
a method to describe the properties of enzymes or receptors models. The values of
these moments in the case of the Langmuir or Michaelis-Menten equation and the
Hill equation are reviewed. They have been calculated for the second degree Adair
equation and in the case of binding site heterogeneity. A method for
generalization to cases of greater complexity is also proposed. The advantage of
this method over the classical ones--graphical representations and derivation of
coefficients like nH, [L]0.9/[L]0.1 ...--is essentially that the moments are
defined by one single value independently of any particular model for the whole
of the saturation curve.
PMID- 9762082
TI - Improved radioisotopic assay for cytidine 5'-triphosphate synthetase (EC
6.3.4.2).
AB - An improved radioassay for cytidine 5-triphosphate synthetase is reported which
employs thin-layer chromatographic methods and provides a number of advantages
over previously available techniques. (i) The method resolves the nucleotides and
the degradation products generated during the time course of the enzymatic
reaction by ascending chromatography employing polyethyleneimine cellulose
plastic-backed sheets. (ii) Determinations of CTP formed and all nucleotide pairs
generated during kinetic analysis of CTP synthetase are greatly simplified,
further facilitating the detection of extraneous enzymatic activities. (iii) The
sensitivity of the assay is enhanced and as little as 50 pmol of product formed
was readily detected in supernatant fluids. This was made possible, in part, by
the addition of NaF and phosphoenolpyruvate which together maintain the
nucleotide triphosphates in the reaction mixture. (iv) A large number of samples
can be handled at one time with highly reproducible results. The synthesis of CTP
from UTP by enzyme preparations from rat liver, hepatomas, and Salmonella
typhimurium LT2 was quantitated with this method.
PMID- 9762083
TI - A simple technique for the measurement of unidirectional calcium influx at the
mucosal surface of organ-cultured embryonic chick duodenum.
AB - Unidirectional calcium influx can be measured by application of a filter paper
blotter saturated with a 45Ca-labeled buffer solution to the mucosal surfaces of
slit-open embryonic chick duodena which had been cultured mucosal side up on
stainless-steel grids. The results obtained with this simple technique support
the contention of a direct involvement of a vitamin D-induced calcium-binding
protein in the transport of calcium across the mucosal surface. Permeability and
inulin space measurements validate the method for measurement of calcium influx
at initial velocity and obviate concern for "unstirred layer" effects. Kinetic
analyses indicate a two step influx process, one saturable at about 5 mM calcium
and the other essentially unsaturable.
PMID- 9762084
TI - A quick hydroxyapatite chromatography technique especially adapted for work with
DNA networks.
AB - During the renaturation of DNAs large networks build up which cannot be eluted
from hydroxyapatite under standard fractionation conditions (60 degrees C, 0.5 M
PB). This is a serious problem especially in plant-DNA renaturation studies as
hyperpolymers may comprise more than half of the renatured DNA mass even at
moderately long initial fragment lengths and low C0t values. Utilizing the acid
solubility of hydroxyapatite a method is outlined which will recover the total
double-stranded DNA fraction and will prepare the column for the next
fractionation in one quick operation. As the method is time saving compared to
the standard hydroxyapatite fractionation procedure its general application may
prove to be useful.
PMID- 9762085
TI - Preparation of lipid-free protein extracts of egg yolk.
AB - 1-Butanol extraction of chicken egg yolk homogenates containing 1 M NaCl yields
lipid-free aqueous solutions of egg yolk proteins. These solutions, after
dialysis, can be applied to a variety of chromatographic media without clogging.
Although some proteins are denatured by this procedure, most of the water-soluble
proteins remain in solution, including biotin-binding protein and riboflavin
binding protein.
PMID- 9762086
TI - Assay of delta-aminolevulinic acid synthetase in homogenates of mouse, rat, and
human liver: species differences in requirement for an exogenous succinyl-CoA
generating system.
AB - Conditions required for optimal assay of low levels of activity of hepatic delta
aminolevulinic acid synthetase have been studied, comparing dilute homogenates of
mouse, rat, and human livers. The assay method used was a modification of that
described by Ebert et al. (Biochim, Biophys, Acta (1970) 208, 236-250), and
livers were studied from both untreated animal and human subjects and subjects
pretreated with porphyrinogenic compounds. In homogenates of mouse and human but
not rat liver, maximal rates of delta-aminolevulinic acid formation required
addition to the incubation mixture of an exogenous system for succinyl-CoA
generation. The requirement for this generating system was increased if livers
from pretreated subjects were frozen and stored prior to assay, suggesting that
the endogenous capacity for succinyl-CoA generation was more labile than delta
aminolevulinic acid synthetase under these conditions. Of the metabolic
inhibitors tested (F-, malonate, and arsenite), only F- (100 mM final
concentration) enhanced activity. Increasing the permeability of mitochondria by
quick freeze-thawing of fresh homogenates just before assay did not increase the
rate of delta-aminolevulinic acid formation.
PMID- 9762087
TI - Chromatographic separation and automated analysis of flavanols.
AB - Flavanols from barley or hops were separated chromatographically and assayed
automatically by reaction with the chromogen, 4-dimethylaminocinnamaldehyde. For
separating the flavanols on Sephadex G-25, gradient elution with water-methanol
mixtures was necessary. The chromogen was specific for flavanols and well suited
to AutoAnalyzer methods. The method appears generally applicable in flavanol
analysis of plant materials.
PMID- 9762088
TI - The resolution of membrane proteins based upon size, charge, and hydrophobicity.
AB - Currently available systems for resolving membrane proteins are based only on
size and charge differences. Recently, it has been shown that Triton-urea-acetic
acid gels which separate proteins on the basis of charge, size and hydrophobicity
are capable of resolving proteins differing only by the substitution of a single
neutral amino acid. We have applied this new method to the resolution of
bacterial envelope proteins. Conditions for optimal resolution of different
bacterial envelope proteins were determined by electrophoresis through transverse
urea and Triton X-100 gradient gels. We have also correlated the components
resolved in this system with those resolved by classical sodium dodecyl sulfate
gel electrophoresis by using two-dimensional slab gels combining the two systems.
Furthermore, envelope protein fractions from different species and strains of
bacteria were compared to identify specific proteins. This system appears to be a
promising method for investigating envelope proteins which are due to missense
mutations.
PMID- 9762089
TI - Chromatographic purification of soluble elastin.
AB - An improved method for extraction and purification of soluble elastin from aortas
of copper-deficient swine has been devised. It depends upon the use of both
acidic and neutral protease inhibitors during preparation. Collagen is first
precipitated with acetic acid. A two-step separation and purification of elastin
from the collagen-free extract is based on absorption of the acidic proteins on
DEAE-cellulose and gel filtration through agarose. The protein recovered is
homogeneous by gel electrophoresis. It has the molecular weight (75,000) and
amino acid composition of the soluble elastin from the same source prepared by
repeated coacervation.
PMID- 9762090
TI - A volume adapter for use in a B-XIV zonal rotor.
AB - A simple adapter for reducing the chamber volume of B-XIV-type rotors is
described. The adapter consists of a disk-like body, which occupies the lower
part of the rotor chamber, and an aluminum sleeve with four septa. The modified
rotor has a volume of 272 ml and has proved very suitable for rate-sedimentation
analysis of small amounts of biological material. The modified rotor is operated
as is a standard B-XIV rotor.
PMID- 9762091
TI - A modified orcinol test for the specific determination of RNA.
AB - The standard orcinol test for estimating RNA is modified and developed as a
specific method for the determination of RNA in the presence of DNA and proteins.
The main differences in the procedure of the modified test when compared to that
of the standard test are preincubation of the samples with H2SO4 before addition
of the orcinol reagent, decreased concentration of orcinol, no addition of
FeCl3.6H2O, and quantitation of RNA at its maximum absorbance under these
conditions at 500 nm where interferences from DNA and proteins were minimal.
PMID- 9762092
TI - Preparation, isolation, analysis, and characterization of 3-benzo[a]pyrenyl-beta
D-glucopyranosiduronic acid: a metabolite of 3-hydroxybenzo[a]pyrene with
potentially high carcinogenic activity.
AB - The aglycone, 3-hydroxybenzo[a]pyrene, was metabolized to 3-benzo[a]pyrenyl-beta
D-glucopyranosiduronic acid in the presence of uridine 5'-diphosphoglucuronic
acid and rabbit liver microsomes. The course of the biosynthetic reaction was
followed by fluorimetry and reverse-phase, paired-ion high pressure liquid
chromatography (HPLC). Also, the HPLC system was used to analyze for glucuronide
and 3-hydroxybenzo[a]pyrene during the isolation procedure. The existence of a
glucuronide of 3-hydroxybenzo[a]pyrene was determined by radiotracer and enzymic
techniques, utilizing the HPLC system. Field desorption and direct inlet mass
spectral techniques were used to characterize the 3-hydroxybenzo[a]pyrene
glucuronide.
PMID- 9762093
TI - Quantitation of human globin chain synthesis by cellulose acetate
electrophoresis.
AB - We have developed a method for the separation and quantitation of human alpha-,
beta-, and gamma-globins utilizing cellulose acetate electrophoresis. The
relative rates of synthesis of globin chains in reticulocytes in peripheral blood
is determined by: (i) incubating intact cells with [35S]methionine; (ii)
preparing globin from the hemolysates; (iii) performing electrophoresis of the
globin on cellulose acetate strips; and (iv) autoradiography or direct
determination of the radioactivity incorporated into each globin chain. The
method is simple and rapid, requires only small amounts of hemolysate (30
micrograms of globin), and provides excellent resolution and reproducible
quantitation of alpha-, beta A-, beta S-, and gamma-globin chains for up to 24
peripheral blood samples at one time. Measurements by this method in patients
with thalassemia variants and sickle-cell disorders correlate well with analysis
of the same samples by carboxymethyl cellulose chromatography. This methodology
may permit more widespread analysis of globin synthesis in the thalassemia
syndromes and may also be useful in the analysis of globins synthesized from
human globin mRNA in cell-free systems.
PMID- 9762095
TI - Protoheme extraction from plant tissue.
AB - A method for reproducibly estimating the protoheme content of plant tissues has
been developed. The tissue sample is homogenized in 80% acetone to remove
pigments and lipids; protoheme is then extracted from the tissue residue with 2%
HCl in acetone and quantitatively transferred into diethyl ether. After
evaporation of the ether, the residue is dissolved in alkaline pyridine, and the
protoheme concentration is estimated from a dithionite-reduced-minus-ferricyanide
oxidized spectrum. When compared to some other methods, this procedure gives
consistently higher yields.
PMID- 9762094
TI - The enzymic synthesis of beta-[32P]UDP-N-acetylglucosamine.
AB - Cells of Micrococcus sp. 2102 incorporate inorganic [32P]phosphate from the
medium into the sugar-phosphate polymer of the wall. Controlled acid hydrolysis
of sodium dodecyl sulphate-extracted cells gives N-acetylglucosamine 6-[32P]
phosphate which can be purified by ion-exchange chromatography and incubated with
UTP in the presence of crude preparations of phosphoacetylglucosamine mutase from
Neurospora crassa and UTP:N-acetylglucosamine 1-phosphate phosphotransferase from
Bacillus licheniformis which act in concert to synthesise beta-[32P]UDP-N
acetylglucosamine.
PMID- 9762096
TI - Measurement of polyadenylic acid by hybridization with polyuridylic acid: a
source of error due to the lability of tritiated polyuridylic acid in
trichloroacetic acid.
AB - During brief exposure to trichloroacetic acid at 0 degree C, significant amounts
of tritiated polyuridylic acid are converted to acid-soluble products. The loss
of polymeric radioactivity is dependent on both acid concentration and the time
of exposure to acid. When trichloroacetic acid precipitation is used to recover
the tritiated polyuridylic acid present in a hybrid with polyadenylic acid,
significant underestimates of the hybridized radioactivity can occur because of
the lability of tritiated polyuridylic acid. Conditions are given which minimize
the lability and permit quantitative recovery of tritiated polyuridylic acid by
trichloroacetic acid precipitation.
PMID- 9762097
TI - A simple method for the elimination of amine contaminants in buffers for single
column amino acid analysis in physiological samples at picomole levels.
PMID- 9762099
TI - A rapid method for the isolation of intracytoplasmic membranes from
Rhodopseudomonas sphaeroides using an air-driven ultracentrifuge.
AB - A method has been developed for the isolation intracytoplasmic (ICM) vesicles
(chromatophores) from Rhodopseudomonas sphaeroides using an air-driven
ultracentrifuge. Application of conventional techniques used for preparative
scale equipment to the air-driven ultracentrifuge allows the rapid isolation of
ICM vesicles from reduced quantities of starting material. Sodium dodecyl
sulfatepolyacrylamide gel electrophoresis profiles of ICM vesicles isolated in
this fashion are essentially indistinguishable from those isolated by
conventional means.
PMID- 9762098
TI - Action of endo-alpha-N-acetyl-D-galactosaminidase on synthetic glycosides
including chromogenic substrates.
AB - The synthetic glycosides, p-nitrophenyl- and o-nitrophenyl-2-acetamido-2-deoxy-3
O-beta-D-galactopyranosyl-alpha- D-galactopyranosides, were found to be effective
chromogenic substrates for an endo-alpha-N-acetyl-D-galactosaminidase. We did not
experience any problems when these substrates were used for the screening of
column fractions during the purification of the endoenzyme from Diplococcus
pneumoniae culture filtrates. However, it should be pointed out that a
combination of exo-beta-galactosidase, capable of cleaving beta 1-->3 linkages,
and an exo-alpha-N-acetyl galactosaminidase would also liberate nitrophenol from
the above substrates. The enzyme had no action on several other synthetic
glycosides tested indicating the strict specificity of this enzyme for the
disaccharide Gal beta-->GalNAc linked via an alpha-linkage to the aglycone. The
enzyme was inactive when the aglycone was methanol but shows activity against the
glycosides of phenol, nitrophenols, serine, and threonine. The use of p
nitrophenyl-2-acetamido-2-deoxy-3-O-beta -D-galactopyranosyl-beta-D
galactopyranoside, which is a competitive inhibitor of the endoenzyme, as an
affinity ligand for the purification of the enzyme is described.
PMID- 9762100
TI - Automatic collector of expired 14CO2 for liquid scintillation counting.
AB - A filtration technique was employed to trap 14CO2 continuously for liquid
scintillation counting. Devices for delivering scintillator and ethanolamine
solutions were combined symmetrically with two fritted-glass aspirators for
alternating operation. The collector was regulated by a fraction collector timer.
Trial and animal tests indicated that the described method was efficient,
reliable, and more convenient for frequent collection over long periods than
alternative methods. The automatic collector was used for metabolic studies of [1
14C] arachidonic acid in rats kept in metabolic cages and the results were
processed by multicompartmental analysis.
PMID- 9762101
TI - Direct physical measurements on substituted agarose gels: evidence for
intercalation of gel-bound ethidium into transfer RNA.
AB - The cation of the salt ethidium bromide (3,8-diamino-5-ethyl-6
phenylphenanthridinium bromide) has been covalently linked to an agarose matrix
through an intermediate 3,3'-diaminodipropylaminosuccinyl spacer arm. Partition
binding and visible absorption spectral measurements on the gel were used to
monitor the binding of transfer RNA to the covalently bound ethidium group.
Direct fluorescence measurements of the formation of the gel-bound complex
indicate that this binding involves the intercalation of the ethidium groups into
the tRNA molecule. Dissociation of the ethidium-tRNA complex was monitored as a
function of sodium chloride concentration by both direct solution spectral
measurement of the released tRNA and by fluorescence quenching measurements of
the dissociation of the intercalation complex. The derivatized gel has been shown
to be capable of the fractionation of tRNA species by elution with a positive
salt gradient under column flow conditions.
PMID- 9762102
TI - Mercury contamination during pH measurement and its effect on creatine kinase
activity.
AB - Inhibition of activity of the enzyme creatine kinase occurs when small volumes of
assay mixtures have their pH measured using a combination pH electrode prior to
addition of the enzyme. This inhibition can be attributed to diffusion of ionic
mercury from the calomel reference electrode through the saturated potassium
chloride salt bridge and the ground glass-liquid junction to the test solution.
The concentration of mercury accumulating in a solution by this process can be
sufficient to affect the activity of an enzyme, and EDTA cannot be used
successfully to scavenge mercury ion and avoid the inhibition.
PMID- 9762103
TI - Removal of sodium dodecyl sulfate from proteins.
AB - Effective removal of sodium dodecyl sulfate from proteins in water or sodium
phosphate buffer was achieved by column chromatography using the ion-retardation
resin AG11A8. An average recovery of 83% protein was obtained, while 0.1 to 1.4
moles of sodium dodecyl sulfate remained on each mole of protein.
PMID- 9762104
TI - N-thiobenzoylsuccinimide as thioacylating reagent in the sequential analysis of
peptides by the solid phase technique.
AB - N-Thiobenzoylsuccinimide is synthesized and proposed as a new thioacylating
reagent. Its use in sequential solid phase degradation of peptides is examined.
PMID- 9762105
TI - Determination of acetaldehyde in rat blood by the use of rat liver aldehyde
dehydrogenase.
AB - A method has been developed for the determination of low concentrations of
acetaldehyde in rat blood. The method involves extraction of blood in perchloric
acid followed by a fluorimetric determination of acetaldehyde in neutralized
extracts by the use of a low K(m) aldehyde dehydrogenase isolated from rat liver
mitochondria. Acetaldehyde concentrations down to 2 to 3 microM could be detected
in blood samples of 0.1 ml containing high concentrations of ethanol (10-40 mM).
Due to its simplicity, sensitivity, and the use of a low-cost fluorimeter, this
enzymatic method should be a valuable complement to gas chromatographic methods
for acetaldehyde determination.
PMID- 9762106
TI - The characterisation of thiobarbituric acid reactivity in human plasma and urine.
AB - The specificity of the thiobarbituric acid reaction (TBA) has been investigated
using techniques of high-performance thin-layer chromatography and
spectrofluorimetry. It was found that malondialdehyde (MDA) derived from
different lipid and nonlipid origins formed the same MDA-TBA complex. This
complex could be separated from other TBA-reactive compounds by both
chromatography and spectrofluorimetry. Normal human plasma and urine both formed
an MDA-TBA complex along with other TBA-reactive compounds. In plasma this was
associated mainly with phosphatidylcholine and appeared to be peroxidic in
reaction. Urine, however, contained polar MDA-forming compounds probably
resulting from the oxidation of 2-deoxyaldoses during the acid-heating stage of
the TBA test.
PMID- 9762107
TI - Assessment of counting efficiencies for labeled protein and other macromolecules
in filter disk assays.
AB - A several-fold greater counting efficiency is observed for protein labeled with
[3H]leucine than for free [3H]leucine using a conventional filter disk assay. A
similar, though less marked, effect is noted for 14C-labeled molecules. These
results are comparable to those reported by others for counting efficiencies of
labeled DNA and deoxynucleotides and illustrate the generality of this effect
with regard to macromolecules and their low-molecular weight precursors. This
phenomenon, presumably due to differences in the distribution of large and small
molecules within filters, gives rise to errors in the quantitation of
macromolecule synthesis if a counting efficiency identical to that of the
precursor is assumed to apply. A convenient method for determining counting
efficiencies of various molecules bound to filters is presented which eliminates
this problem.
PMID- 9762108
TI - Automated analysis of common basic amino acids, mono-, di-, and polyamines,
phenolicamines, and indoleamines in crude biological samples.
AB - A fully automated, fast, and sensitive method for the separation of common basic
amino acids and mono-, di-, and polyamines as well as phenolic- and indoleamines
is described. Picomole level determination of hydroxytryptophan, tryptophan,
histidine, lysine, ethanol amine, arginine, noradrenaline, diaminopropane,
putrescine, histamine, cadaverine, dopamine, hexamethylenediamine, agmatine,
tyramine, phenethylamine, serotonin, 5,6-dihydroxytryptamine, 5
methoxytryptamine, tryptamine, spermidine, and spermine is carried out by ion
exchange column chromatography on a single sample in 170 min of total analysis.
This method is well suited for crude extracts without preliminary purification,
thus reducing preparative losses. The reproducibility of the method has been
studied and the percentage recovery of the different compounds after column
chromatography is reported. Its application to crude samples from different
biological sources such as microorganisms, vegetables, platelets, and urine is
presented. This method could serve as a powerful tool for the analysis of these
amino compounds in which there is currently a considerable interest.
PMID- 9762109
TI - Staphylococcal protein A-sepharose columns and the characterization of measles
virus-specific polypeptides in persistently infected cells.
AB - Viral polypeptides in extracts prepared from [35S]methionine-labeled human
epithelial carcinoma cells persistently infected with measles virus were reacted
with virus-specific antisera. Microcolumns of staphylococcal protein A linked to
Sepharose were used to isolate antigen-antibody complexes that contained few
contaminating host polypeptides. Measles virus polypeptides in these complexes
could be identified readily on sodium dodecyl sulfate-polyacrylamide gels even
when antiserum with low reactivity toward the viral antigens was used.
PMID- 9762110
TI - Analytical micro-preparative electrophoresis: quantitation of phosphoglucose
isomerase isoenzymes.
AB - A simple micro-preparative electrophoresis apparatus is described using a thin
vertical slab gel and continuous elution through a narrow horizontal slot.
Phosphoglucose isomerase (PGI) isoenzymes in lysates of 0.2 to 100 microliters of
erythrocytes were separated using this system and their activities determined
using an on-line, air-segmented, continuous flow assay. Ninety-five percent
recovery of the separated isoenzymes after electrophoresis was achieved and the
factors influencing recovery of PGI and hemoglobin were investigated. Thus,
quantitative recovery has been achieved without any loss of resolution. Up to 29
successive separations of PGI isoenzymes have been carried out on a single gel.
PMID- 9762111
TI - Vitamin D3 in plasma: quantitation by mass fragmentography.
AB - Combined gas chromatography-mass spectrometry with multiple-ion detection is used
to quantitate vitamin D3 in plasma samples. Extensive cleanup of the plasma
extract prior to analysis is required before mass fragmentographic analysis is
possible, i.e., solvent extraction, digitonin precipitation, Lipidex column
chromatography, and derivatization. Low resolution mass fragmentography is
performed by monitoring simultaneously the molecular ions of the
heptafluorobutyric esters of the all-trans isomer of vitamin D3 and
dihydrotachysterol2, which is used as an internal standard. This new method uses
5 ml of plasma and it is specific and sensitive to 600 pg of vitamin D3. This
assay shows that in plasma of normal adult subjects there is a vitamin D3
concentration of 5 to 11 ng/ml, lower than those values reported for biological
and competitive protein binding assays. Specifically the method described offers
potential as an eventual reference method.
PMID- 9762112
TI - A new method for allantoin determination and its application in allantoin
determination in Agrostemma githago L. Seed.
AB - We have established several optimal conditions for qualitative and quantitative
allantoin determination by applying Ehrlich's reagent. The limit of detection for
allantoin determination amounts to 5 x 10(-6) mM. Allantoin is determined
quantitatively by measuring the absorbance at 440 nm (from 300 to 1000
micrograms/ml). The color of the complex becomes stable by standing for 10 min at
room temperature. We have used these conditions for allantoin determination in
Agrostemma githago seed.
PMID- 9762113
TI - Numerical analysis of thermal denaturation of nucleic acids.
AB - Denaturation of DNA molecules by stepwise incrementation of the temperature leads
to melting profiles showing a fine structure, composed of individual melting
modes. A method is described by which quantitative physical information brought
by the modes can be extracted from the melting profile. Related problems such as
data editing and smoothing are also discussed.
PMID- 9762114
TI - Sources of error in the channels ratio method for efficiency determination in
liquid scintillation counting.
AB - The reliability of the channels ratio method for determining counting efficiency
in liquid scintillation counting was investigated. It was found that the
efficiency of counting gels, cloudy samples, two-phase samples, samples in which
the radioactive material was precipitating, and samples on solid supports could
not be reliably determined from a normal quench correction curve. A curve
constructed from external standard channels ratios was unreliable when mixing
different vial sizes and sample volumes, but one constructed from sample channels
ratios was not. It was also found that variation in instrument performance can
result in large errors unless samples and standards are counted together.
Statistical error changed relatively little within the range of ratios 0.3 to
0.8.
PMID- 9762115
TI - A further modified tissue homogenizer.
PMID- 9762116
TI - Characterization of density gradients prepared by freezing and thawing a sucrose
solution.
AB - Density gradients of sucrose can be prepared in large numbers by successive
freezing and thawing of sucrose solutions. Gradients of other solute molecules,
such as salt and detergents, also form and this could affect subsequent
sedimentation behavior of some molecules. However, the sedimentation behavior of
native and denatured DNA of bacteriophage lambda was essentially isokinetic under
the conditions used thus making these gradients comparable with ones prepared
manually, at least for preparative sedimentation work with nucleic acids.
PMID- 9762118
TI - Quantitation of nanogram amounts of protein using [3H]dinitrofluorobenzene.
PMID- 9762117
TI - A simplified procedure for organic phosphorus determination from phospholipids.
AB - We describe an improved method for the determination of organic phosphorus from
phospholipids. It is the combination of a very fast mineralization step followed
by the estimation of liberated phosphate by means of malachite green. This method
is accurate, simple, and sensitive.
PMID- 9762119
TI - Zone collector and transfer device for thin-layer chromatography.
PMID- 9762120
TI - Automated assay of glycosidases.
AB - The Technicon Basic Auto Analyzer sampler system was modified for simultaneous
sampling of glycosidase(s) and substrate-buffer solutions. The inexpensive
modification allows performance of automated enzyme analyses and enzyme kinetic
studies with minimal consumption of substrate and/or enzyme.
PMID- 9762121
TI - A simple procedure for regeneration of an organomercurial agarose column.
PMID- 9762122
TI - An improved synthesis of malonyl-coenzyme A.
AB - A method for the synthesis of [14C]malonyl-Coenzyme A starting with 10 mumol of
[14C]malonate is reported. The synthesis is accomplished with yields of 48 +/- 4%
(1 sigma, n = 6) using a procedure which does not require the isolation or
purification of any intermediates.
PMID- 9762123
TI - A program which automatically quantitates gel electrophoretic autoradiograms.
AB - The use of a computer-coupled film scanner to measure and analyze autoradiograms
of gel electropherograms is described. A program has been written which fits
Gaussian curves to the complex band pattern that constitutes a density profile
without the need for estimated parameters in the input. The great majority of the
fits are satisfactory. This program, which is written in FORTRAN, runs on a
small, inexpensive computer. Another program which approximates a Gaussian least
squares fit has been run for comparison; this procedure can also be used to
refine occasional unsatisfactory fits. Finally, a program has been written which
sums the density profile within specified limits, so that the integrated
intensities of bands due to isolated protein components may be found.
PMID- 9762124
TI - Automated activation energy.
AB - A method and equipment used for automated determination of activation energies on
a single sample are described. Essentially identical results are obtained in both
automated and manual methods. The automated method is particularly valuable for
minimizing the amounts of enzyme, substrate, and time required. Further, errors
in repetitive pipetting and calculation are eliminated.
PMID- 9762125
TI - A single-column amino acid analysis method which resolves hexosamines and several
cysteine derivatives.
AB - A single-column amino acid analysis method is presented for use in structural
studies of glycoproteins. The system gives excellent resolution of glucosamine,
galactosamine, cysteic acid, CM-cysteine, AE-cysteine, the internal standard
norleucine, and all amino acids normally present in protein hydrolysates.
PMID- 9762126
TI - Chromatographic determination of angiotensin-converting enzyme and angiotensinase
activity.
AB - An analytical method utilizing an automatic amino acid analyzer is described for
the separation, identification, and measurement of 5 to 50 nmol of angiotensin I,
angiotensin II, [Des-Phe8]angiotensin II, Phe-His-Leu, His-Leu, isoleucine,
leucine, tyrosine, and phenylalanine. Aminex A-5 cation-exchange resin (0.9 x 15
cm) is sequentially eluted with three sodium citrate buffers: pH 3.25, 0.2 N; pH
4.85, 0.54 N, and pH 6.5, 0.39 N at 60 and 80 degrees C. Reaction with ninhydrin
is used for detection. This chromatographic system was used to determine
angiotensin-converting enzyme activity and the angiotensinase activity of rabbit
brain endopeptidase B. In each assay, the unhydrolyzed substrate and both
products were measured simultaneously in one step without pretreatment of the
hydrolysate. Products were recovered in 1:1 molar ratios and the overall recovery
of an hydrolyzed substrate of products was quantitative.
PMID- 9762127
TI - A new, fast, and very sensitive bioluminescence assay for phospholipases A and C.
AB - A new, simple, and very sensitive assay for phospholipase A and C is described.
The assay is based on the bioluminescence developed by the mutant of the
bacterium Beneckea harveyi as a response to myristic acid released from
dimyristoyl phosphatidylcholine by either phospholipase A or by a phospholipase C
lipase coupled system. It is possible to assay these enzymes at a rate
corresponding to a release of as little as 1 to 2 pmol of myristic acid per
minute.
PMID- 9762128
TI - Isolation of circular viral and complementary strand DNA from bacteriophage f1
duplex replicative-form DNA.
AB - A general method has been developed for the large scale isolation of intact,
circular, single-stranded DNA molecules of each strand from supercoiled duplex
DNA. The method involves the conversion of the supercoiled duplex DNA to singly
nicked, relaxed duplex DNA; denaturation of the duplex DNA; separation of
circular DNA molecules from linear DNA molecules; and separation of circular plus
and minus strands. All separations involve zone sedimentation. No isopycnic
gradient centrifugation is required. The last step in the purification, the
separation of plus and minus strands, can be easily adapted for small scale
analytical measurements of the amounts of plus and minus strand DNA.
PMID- 9762129
TI - Analytical techniques for cell fractions. XXIII. A stable thermal gradient device
for heat denaturation studies on proteins.
AB - The ISO-DALT two-dimensional electrophoretic system (1,2), based on the method of
O'Farrell (3), is capable of performing large numbers of analysis on complex
mixtures of proteins. However, both separations employed are carried out under
dissociating or denaturing conditions and no enzyme activities are readily
observable in the analyzed proteins. In order to identify the spots corresponding
to particular enzymes, it is therefore necessary to employ some nondestructive
resolving technique first and as a second step to perform both enzyme and two
dimensional electrophoretic analyses on the fractions generated. By correlating
enzyme activity with intensity of various spots on the two-dimensional gels
throughout the series of initial fractions, identifications, can be made. This
approach, unlike the more direct immunoprecipitation methods (4), requires the
running of large numbers of enzyme analyses and two-dimensional gels and some
convenient initial resolving procedure. Convenient and rapid techniques for the
analyses (5,6) and gels (1,2) have been described previously in this series and
elsewhere. This paper deals with the use of selective denaturation in a
temperature gradient as an initial resolving procedure and describes a simple
thermal gradient device for generating such a gradient.
PMID- 9762130
TI - Purification of small peptides labeled with Bolton-Hunter reagent.
AB - A method utilizing high-voltage electrophoresis on paper is described whereby a
pentapeptide (Asp-Ser-Asp-Pro-Arg) labeled with Bolton-Hunter reagent is
separated from hydrolyzed reagent and unreacted peptide and is recovered from the
electrophoretogram in high yield. The general applicability to other peptides is
discussed.
PMID- 9762131
TI - An improved assay for hexokinase activity in human tissue homogenates.
AB - An improved method has been developed for the assay of hexokinase (EC 2.7.1.1)
levels in human tissue homogenates. The enzyme is quantitated by the
spectrophotometric measurement, at 340 nm, of NADPH formed according to the
reaction scheme: [formula: see text] In tissue homogenates a number of enzymes
are present which can interfere with the assay by reacting with substrates or
products of the assay reactions. In the described procedure hexokinase is assayed
directly in homogenates under conditions in which the effect of possible
contaminating enzymes (glucose dehydrogenase, EC 1.1.1.47; glucose 6-phosphatase,
EC 3.1.3.9; glucose phosphate isomerase, EC 5.3.1.9; 6-phosphogluconate
dehydrogenase EC 1.1.1.44; and NADP-reducing enzymes) are eliminated. Precision
studies on the assay gave within-day reproducibility of 4.3% (CV) on a tissue
having a mean activity of 1.68 U/g of tissue, and day-to-day variability of 15%
(CV) for a tissue averaging 1.83 U/g of tissue.
PMID- 9762132
TI - An agarose gel electrophoretic method for analysis of sulfated glycosaminoglycans
of cultured cells.
AB - Agarose disc gel electrophoresis has been adapted to achieve the separation of
the major sulfated glycosaminoglycans produced by cells in culture. By use of
buffers containing barium ion, mixtures of chondroitin sulfate, dermatan sulfate,
and heparan sulfate are well resolved into discrete bands. The technique can be
used preparatively as well as analytically to separate quantities of
glycosaminoglycans up to a milligram in a 6-mm diameter gel.
PMID- 9762133
TI - A simplified polyacrylamide gel electrophoresis apparatus for simultaneous
application of multiple buffer systems or detergent combinations.
AB - A previous design of an apparatus for the simultaneous fractionation by
polyacrylamide gel electrophoresis in 10 different buffer systems (1) was
replaced by a greatly simplified new design, employing small, cylindrical buffer
partitions within the lower buffer reservoir and/or upper buffer reservoir of a
conventional, temperature-regulated polyacrylamide gel electrophoresis apparatus
for cylindrical gels. The apparatus was tested in application to the problem of
simultaneous polyacrylamide gel electrophoresis in different buffer systems with
the purpose of optimizing the operative pH for a particular fractionation
problem. It was also applied to fractionations in a single buffer system to which
various combinations of ionic and nonionic detergents were admixed.
PMID- 9762134
TI - Quantitation of methionyl peptides in nanomole quantities by a fluorometric
method.
AB - A quantitative and highly specific method to determine low concentrations of
methionyl peptides, which do not contain tryptophan or cysteine residues, has
been developed. The method is based on the stoichiometry and selectivity of N
chlorosuccinimide (NCS) towards methionine and N-acetyltryptophan. N
Chlorosuccinimide reacts with N-acetyltryptophan in a 1:1 ratio to produce the N
acetyl-2-oxindolealanine--a derivative essentially devoid of fluorescence. The
decrease in fluorescence intensity is approximately linear with respect to the
NCS concentration. Preincubation of NCS with methionine or methionyl peptide
consumes a stoichiometric amount of the reagent and the unreacted NCS is
quantitated by the decrease in fluorescence intensity resulting upon incubation
of the mixture with 1 eq of N-acetyltryptophan. Less than 1 nmol of methionyl
peptide can be accurately quantitated by this method.
PMID- 9762135
TI - Synthesis of UDP-N-[1-14C]acetyl D-glucosamine and UDP-N-[1-14C]acetyl-D
galactosamine from [1-14C]acetate.
AB - Procedures for the preparation of UDP-N-[1-14C]acetyl-D-glucosamine and UDP-N-[1
14C]acetyl-D-galactosamine with very high specific activities are described. The
overall yield based on the amount of [1-14C]acetate used is greater than 80%. The
N-acetyl-D-glucosamine-alpha-1-phosphate used in this synthesis is prepared by
phosphorylation of tetraacetyl-D-N-acetylglucosamine with crystalline phosphoric
acid. N-acetyl-D-glucosamine-alpha-1-phosphate is then deacetylated in anhydrous
hydrazine with hydrazine sulfate as a catalyst. D-glucosamine-alpha-1-phosphate
is N-acetylated with [14C]acetate using N-ethoxycarbonyl-2-ethoxy-1,2
dihydroquinoline as the coupling agent. The acetylated product is coverted to the
UDP derivative with yeast UDP-N-acetyl-D-glucosamine pyrophosphorylase. UDP-N-[1
14C]acetylgalactosamine is prepared by acetylation of UDP-galactosamine using [1
14C]acetate and N-ethoxy-carbonyl-2-ethoxy-1,2-dihydroquinoline. UDP
galactosamine is prepared enzymatically using galactokinase and galactose-1
phosphate uridyltransferase. The labeled products, isolated and characterized by
ion-exchange and paper chromatography, were active as substrates in glycosyl
transferase systems.
PMID- 9762136
TI - Comparison of dark-field and bright-field incident illumination for in vivo
measurements of reduced pyridine nucleotides.
AB - Bright-field and dark-field illumination techniques for in vivo measurements of
reduced pyridine nucleotide fluorescence were compared in 15 rats during periods
of normocapnia, hypocapnia, hypercapnia, and anoxia. Parameters investigated
included fluorescence, cortical reflectance, cortical blood flow, and
electroencephalograms. In normal brain, with preserved autoregulation, reduced
pyridine nucleotide fluorescence was constant through a wide range in Pa(CO2),
cortical blood flow, and cerebral blood volume in animals studied using vertical
illumination (bright-field) techniques. There was a marked increase in reduced
pyridine nucleotide fluorescence at death from anoxia. Artifacts were reduced by
monochromators for excitation, emission, and reflected light; low-intensity
vertical excitation energy and high-sensitivity recording instrumentation; and a
small avascular (123 microns) field. Potential sources of error include
photodecomposition, hemoglobin interference from absorption and reflectance, and
light scattering. Vertical excitation techniques using a small field appeared to
give more reliable and reproducible results than circumferential techniques using
a larger field of observation.
PMID- 9762137
TI - Quantitative Limulus lysate assay for endotoxin activity: aggregation of
radioiodinated coagulogen monomers.
AB - This communication describes a modification of the Limulus lysate assay which
allows precise quantitation of picograms of bacterial lipopolysaccharide
activity. The method measures the incorporation of 125I-labeled coagulogen
monomers into the lysate clot as a function of lipopolysaccharide concentration.
The method is more precise and requires less lysate than the previously described
quantitative assays for endotoxin activity.
PMID- 9762138
TI - Measurement of S-adenosyl-L-methionine levels by SP Sephadex chromatography.
AB - Cation-exchange chromatography with sulfopropyl Sephadex was used to measure the
levels of S-[methyl-3H]adenosyl-L-methionine synthesized by L1210 cells in vitro.
Separation of S-[methyl-3H]adenosyl-L-methionine from [methyl-3H]methionine and
other metabolites was achieved by stepwise elution with varying concentrations of
HCl.
PMID- 9762139
TI - S1 nuclease-specific nicking of mitochondrial DNA containing displacement loops.
AB - Conditions are described in which the single strand-specific nuclease S1
selectively nicks mitochondrial DNA containing displacement loops without nicking
supercoiled mitochondrial DNA. Using these conditions, the percentage of
molecules containing displacement loops can be easily and accurately determined.
This method is superior to the traditional electron microscopic examination for
assessing the frequency of displacement loop-containing molecules. In addition,
this method permits the determination of the relative specific activities of
displacement loop and nondisplacement loop-containing mitochondrial DNA after
various radioactive labeling protocols. S1 nuclease is shown to cleave the
displaced strand of the displacement loop, to partially degrade the 7S-initiation
strand, but not to cleave the parental template strand complementary to the 7S
initiation strand. The final product is a nicked circular molecule with at least
two breaks localized within the displacement loop region in only one of the two
parental strands.
PMID- 9762140
TI - The effect of thiodiglycol and dithiothreitol on the alkaline hydrolysis products
of certain amino acid phenylthiohydantoins.
AB - The thiazolinone and phenylthiohydantoin derivatives of most amino acids can be
hydrolyzed with alkaline dithionite to generate the free amino acid. The
acidification of this hydrolysate with 3 N HCl containing thiodiglycol leads in
the case of glutamic acid, glutamine, aspartic acid, asparagine, and S-carboxy
methylcysteine to the generation of ninhydrin-reacting components having the
chromatographic properties of other amino acids. The use of dithiothreitol
instead of thiodiglycol appears to be more satisfactory in most instances.
PMID- 9762142
TI - The determination of similarities in amino acid composition among proteins
separated by two-dimensional gel electrophoresis.
AB - A simple and rapid procedure has been developed to determine similarities in
amino acid composition among cellular proteins separated by two-dimensional gel
electrophoresis. Cells in tissue culture are simultaneously labeled with two
different amino acids each tagged with a different radioisotope. The proteins are
then separated on two-dimensional gels and their location on the gels determined
by Coomassie-blue staining or autoradiography. Elution of the protein from the
appropriate region of the gel followed by liquid scintillation counting yields an
isotope ratio which reflects the ratio of the two amino acids in the protein.
Examples of the use of this technique in analyzing mutant proteins, proteins
altered by carbamylation, and cell proteins with similar amino acid composition
(e.g., actin and tubulin) are given.
PMID- 9762141
TI - Separation of acetic and propionic acid analogs of L-thyroxine and L
triiodothyronine by thin-layer chromatography.
AB - A thin-layer chromatographic method is described for the separation of the acetic
and propionic acid analogs of thyroxine and triiodothyronine, which are
inseparable by currently available methods. The separation is achieved on silica
gel H in a solvent system consisting of methylacetate-2.5% ammonia (w/v) (95:5
v/v). The complete analysis takes 2 h.
PMID- 9762143
TI - A rapid, enzymatic assay for the measurement of inorganic pyrophosphate in animal
tissues.
AB - A simple, rapid enzymatic assay for the determination of inorganic pyrophosphate
in tissue and plasma has been developed using the enzyme pyrophosphate--fructose
6-phosphate 1-phosphotransferase (EC 2.7.1.90) which was purified from extracts
of Propionibacterium shermanii. The enzyme phosphorylates fructose-6-phosphate to
produce fructose-1,6-bisphosphate using inorganic pyrophosphate as the phosphate
donor. The utilization of inorganic pyrophosphate is measured by coupling the
production of fructose-1,6-bisphosphate with the oxidation of NADH using fructose
bisphosphate aldolase (EC 4.1.2.13), triosephosphate isomerase (EC 5.3.1.1), and
glycerol-3-phosphate dehydrogenase (NAD+)(EC 1.1.1.8). The assay is completed in
less than 5 min and is not affected by any of the components of tissue or plasma
extracts. The recovery of pyrophosphate added to frozen tissue powder was 97 +/-
1% (n = 4). In this assay the change in absorbance is linearly related to the
concentration of inorganic pyrophosphate over the curvette concentration range of
0.1 microM to 0.1 mM.
PMID- 9762144
TI - A radioimmunoassay for tetrahydrocortisol.
AB - A radioimmunoassay for urinary tetrahydrocortisol (THF) is described. Antibodies
were produced in rabbits against a THF-monohemisuccinate:bovine serum albumin
conjugate. The radioimmunoassay procedure involves enzymic hydrolysis of the
urine, extraction with ethyl acetate, radioimmunoassay, and separation of free
from bound steroid with Somogyi reagents. The antibody showed some cross-reaction
with tetrahydro substance S (36%) which does not occur in urine in appreciable
amounts and with tetrahydrocortisone (10%) which does. An analysis of monkey
urine extracts before and after tlc purification revealed that the THF antibody
was specific enough to permit assay of urines for THF during stress experiments
without a purification step. THF values obtained correlated very highly with 17
hydroxycorticosteroid values on the same urines obtained from monkeys during a
chair restraint experience (r = 0.97). Also for comparison purposes these same
urines were assayed for free THF, total cortisol, and free cortisol. The free
(unconjugated) steroids showed the greatest percentage increase over basal
levels.
PMID- 9762145
TI - Colorimetric determination of succinic acid using yeast succinate dehydrogenase.
AB - An enzymatic method for the rapid determination of succinic acid in biological
fluids was developed utilizing yeast mitochondria as a source of succinate
dehydrogenase. The yeast enzyme catalyzes a complete stoichiometric reduction of
2- (p-iodophenyl)-3-(p-nitrophenyl)-5-tetrazolium chloride to a red formazan. The
formazan is extracted into ethylacetate and its absorbance measured at 490 nm.
The method is simple, specific, reproducible, and very sensitive (0.01 to 0.14
mumol). The yeast enzyme can be stored in liquid nitrogen for periods of at least
30 days with no significant change in specific activity. In this respect it is
superior to a variety of succinate dehydrogenase preparations from animal
tissues. The method was applied to measurement of succinic acid excreted by
nonproliferating yeast cells metabolizing glucose. Derepressed yeast cells
secreted several-fold as much succinic acid as repressed cells submitted to
identical test conditions.
PMID- 9762146
TI - Preservation of algal and higher plant ribosomal RNA integrity during extraction
and electrophoretic quantitation.
AB - Isolation of high molecular weight ribosomal RNA from the wall-less alga
Olisthodiscus luteus and the angiospermous plant Sauromatum guttatum is
described. It has been found that a buffer which contains magnesium must be used
to successfully isolate Olisthodiscus rRNA whereas the isolation of intact
Sauromatum rRNA requires a buffer system containing a high amount of the chelator
EDTA. Sauromatum but not Olisthodiscus extracts were contaminated with
ribonuclease unless the inhibitor diethylpyrocarbonate was used during the
ribonucleic acid extraction procedure. Nuclease levels were monitored by
coincubating [3H]-labeled Escherichia coli ribosomal RNA with the experimental
RNA samples. The effects of detergents on the isolation and quantitation of RNA
are presented, and methods to avoid loss of highly thermolabile plant ribosomal
RNA species are discussed.
PMID- 9762147
TI - A simple method for synthesizing [gamma-32P]nucleoside triphosphates using
[32P]acetylphosphate and acetate kinase.
AB - A simple, rapid, and inexpensive method is described for the synthesis of gamma
32P-labeled ribo- or deoxyribonucleoside triphosphates. The procedure involves
chemical synthesis of [32P]acetylphosphate and subsequent phosphorylation of
nucleoside diphosphates using acetate kinase (EC 2.7.2.1) and a final
purification step. The entire procedure is performed 8 h or less.
PMID- 9762148
TI - Colorimetric assay of sialic acid by a methyl-3-benzothiazolinone-2-hydrazone
reactant.
AB - A colorimetric assay of sialic acid has been developed in which bound sialic acid
is oxidized by periodic acid so as to quantitatively release formaldehyde. In the
second step of the reaction formaldehyde reacts with methyl-3-benzothiazolinone-2
hydrazone, giving a colored compound. This method does not require a prior
hydrolysis and presents the advantage of great accuracy.
PMID- 9762149
TI - Isolation of protein subunits by coupling to an insoluble matrix: analysis of
interactions and application to G-actin.
AB - A criterion has been devised for the assessment of intermolecular contacts
between protein subunits coupled to a gel matrix. After reversible coupling by
way of disulfide groups to Sepharose 4B, the system is exposed to a bifunctional
reagent. The protein is then released by reduction, and the proportion of dimers
and higher oligomers formed by cross-linking is determined by gel
electrophoresis, followed by densitometry of the stained gels. Experiments were
performed with G-actin coupled to dithio-2-dipyridyl Sepharose 4B. At low
concentration of coupled protein, no species other than the monomer were
obtained; under these conditions any intermolecularly cross-linked species would
represent pre-existing associated states coupled to the matrix. At higher protein
concentrations dimers and higher species progressively appear. Their proportion
is much higher than predicted on the basis of a random statistical distribution
of coupled molecules throughout the accessible internal volume of the matrix. It
follows that protein-protein contacts can occur either because of high
flexibility of the polysaccharide chains of the matrix, or because the protein is
partly (but not wholly) present as a shell on the surface of the beads. With Affi
gel 10, which has N-hydroxysuccinimide ester coupling groups, similar experiments
were performed, taking advantage of the degradation of the matrix under
relatively mild acid conditions. In this case the degree of cross-linking was
much lower than in the Sepharose 4B system at the same protein concentration.
However, this medium proved unsatisfactory for the measurement of interactions of
the bound actin with other muscle proteins present in the mobile phase. The
results with Sepharose 4B support the validity of previous studies on interaction
of monomeric actin with other muscle proteins.
PMID- 9762150
TI - Estrogen determination using liquid chromatography with precolumn fluorescence
labeling.
AB - A liquid chromatography procedure is described for the determination of some
estrogens using fluorescence detection. The estrogens are labeled by precolumn
derivatization with 5-dimethylaminonaphthalene-1-sulfonylchloride (dansyl
chloride) and chromatographed on a reversed-phase, C-18 column with a mobile
phase consisting of methanol, water, and acetic acid. The eluted analytes are
measured with a fluorescence detector using excitation and emission wavelengths
of 350 and 540 nm, respectively. The chief advantage of this new procedure is its
sensitivity, requiring smaller amounts of sample to detect and quantitate
estrogens in biological materials. We could detect less than 400 pg of estriol.
With our procedure, this corresponded to about 25 ng in the final reaction
mixture, before derivatization. The use of smaller sample volumes could improve
this limit. Linearity for dansylated estriol, estrone, and estradiol was
excellent over the estrogen range below 100 micrograms in the sample. This
corresponds to approximately 1.7 micrograms on the column. Within-run precision
was better than 5% for the full extraction and derivatization procedure for
estriol from pregnancy urine samples. Chromatography is complete within 10 min
for dansylated estriol, estrone, and estradiol.
PMID- 9762151
TI - A rapid method for hemoglobin chain recombination.
AB - A rapid method for hemoglobin chain recombination which gives a homogeneous
product was developed. The method utilizes a small carboxymethylcellulose column
as a medium for chain recombination and concentration of the hemoglobin.
Equimolar amounts of p-hydroxymercuribenzoate derivatives of alpha- and beta
chains were mixed with 300 x molar excess of beta-mercaptoethanol over the p
hydroxymercuribenzoate groups. After 10 min of incubation in an ice bath, the
mixture was adjusted to pH 5.85, and was loaded on a carboxymethylcellulose
column. The column was washed with 10 mM phosphate buffer-1 mM Na2EDTA-47 mM beta
mercaptoethanol, pH 5.85 and then with 10 mM phosphate buffer, pH 5.85. The
hemoglobin was eluted from the column by use of 15 mM K2HPO4. The hemoglobin was
homogeneous on polyacrylamide gel electrophoresis and had a visible spectrum,
electrophoretic mobility, and number of -SH groups comparable to those shown by
control hemoglobin.
PMID- 9762152
TI - Interaction of antibody with antigen immobilized on polystyrene latex beads:
characterization by density gradient centrifugation.
AB - Isopycnic banding by density gradient centrifugation was used to measure density
changes in complexes formed by the interaction between antigen and antibody
immobilized on polystyrene latex beads (diameter, 0.109 +/- 0.0025 micron).
Measurements of density changes allowed calculation of the interacting masses
under the given experimental conditions. Interaction equilibrium constants and
free energy change for two sets of reactions, bovine IgG and anti-bovine IgG
(rabbit) IgG and rabbit IgG and anti-rabbit IgG (goat) IgG systems, were
calculated from isopycnic banding density gradient centrifugation runs. The
procedure demonstrates a new method of obtaining quantitative information on
antigen-antibody interactions.
PMID- 9762153
TI - Arylamidation and arylation by the carcinogen N-2-fluorenylacetamide: a sensitive
and rapid radiochemical assay.
AB - N-acetoxy-N-arylacetamides, which are generally considered as an ultimate
carcinogenic form of the corresponding N-arylacetamides, react with the cellular
macromolecules (nucleic acids, proteins, etc.) to give two types of adducts: (I)
arylamidation and (II) arylation addition products. In this paper, we present a
radiochemical determination of the amount of N-2-fluorenylacetamide bound to DNA
via arylamidation or arylation, respectively. This assay is based upon the
difference of stability under weak alkali hydrolysis conditions (0.1 N NaOH, 75
degrees C, 2 h) of the specifically 14C-labeled N-acetyl group of the N-2
fluorenylacetamide residue linked to the macromolecule either via arylamidation
or arylation. Native DNA which has been reacted with N-acetoxy-N-2
[14C]acetylaminofluorene exhibits 16% of the fluorene adducts linked to the bases
via arylation. On the other hand, denatured DNA reacts with the fluorene
derivative to give almost only arylamidation addition products.
PMID- 9762154
TI - A new chromogenic substrate for angiotensin-converting enzyme.
AB - The compound para-nitrobenzyloxycarbonylglycyl-(S-4-nitrobenzo-2-oxa- 1,3
diazole)-L-cysteinylglycine [NO2ZGly(S-NBD)CysGly] with an absorption maximum at
423 nm is readily hydrolyzed by angiotensin-converting enzyme (EC 3.4.15.1.
peptidlyldipeptide hydrolase) to yield the S-benzfurazan derivative of
cysteinylglycine. An internal S-->N shift occurs immediately to yield the N
benzfurazan derivative which in turn reacts with the sulfhydryl reagent 4,4'
dithiodipyridine to produce the mixed disulfide with an intense absorption at 461
nm. The maximum difference in molar absorptivity of 13,000 M-1 cm-1 occurs at 470
nm.
PMID- 9762155
TI - An artifact produced by boiling adenyl cyclase reaction mixtures prior to the
cyclic AMP-radioimmunoassay.
AB - An artifact of procedure has been detected in the adaptation of the cAMP
radioimmunoassay to the analysis of adenyl cyclase activity. When reaction
mixtures containing ATP and MgCl2 were boiled to terminate the enzyme assay, a
cAMP-like decrease in antigen-binding was found. This decrease was dependent upon
the presence of ATP, was linear to at least 5 min of boiling time, and could be
destroyed with the addition of commercial phosphodiesterase. As significant
levels of the nonenzymatically formed product resulted only when samples were
boiled, alternative methods of terminating cyclase reactions are suggested.
PMID- 9762156
TI - Molar absorbance of tRNA.
AB - Examination of some published values suggests that the concentration of most
tRNAs can be evaluated on the basis of epsilon 260 = 7200/base, in magnesium
buffer.
PMID- 9762157
TI - Modification of aspartic acid residues to induce trypsin cleavage.
AB - 1,2-Diaminoethane and diaminomethane were coupled to aspartic acid residues in
small peptides by means of a water-soluble carbodiimide. The resulting modified
side chains sufficiently resembled lysine for trypsin to cleave the peptides.
Similar modification of glutamic acid residues in peptides gave little or no
susceptibility to trypsin.
PMID- 9762158
TI - [Superficial cancer of the stomach at the dawn of the XXI century].
PMID- 9762159
TI - [Superficial cancer of the stomach in the area of Calvados from 1978 to 1990.
Epidemiology and prognostic factors].
AB - AIMS OF THE STUDY: The 5-year survival rate of gastric cancer is less than 20% in
cancer registries. The prognosis of early gastric cancer is much better but this
diagnosis is rare in Europe. The aim of the study was to evaluate the prognosis
and trends in the incidence of early gastric cancer in the area of Calvados
(France) during a 13-year period. METHODS: Between 1978 and 1990 the Digestive
Cancer Registry of Calvados recorded 1,160 new cases of gastric cancer. The
diagnosis of early gastric cancer was defined according to the Japanese
Gastroenterological Society criteria. Prognostic factors were determined with
univariate and multivariate analysis. RESULTS: One hundred patients had early
gastric cancer (8.6%). This rate did not change significantly during the period.
The mean age was 64.2 +/- 1.5 in males and 64.8 +/- 2.2 in females and 39% of
patients were older than 70. A precancerous condition was present in 56% of cases
on the surgical specimen. A total gastrectomy was performed in 23% of cases and a
subtotal gastrectomy in 72% of cases. The postoperative mortality was 5% and the
5-year relative survival was 86.8% +/- 4.6. Univariate and multivariate analysis
found a better prognosis in patients younger than 75 or in patients with a
superficial or excavated gross appearance compared with those older than 75 or
with a protruded type. Lymph node metastasis, depth of invasion, size of the
tumor and histologic differentiation did not influence significantly the outcome.
CONCLUSION: According to the data of the Cancer Registry of Calvados the
proportion of Early Gastric Cancer was low and did not change between 1978 and
1990. The prognosis of EGC is good, mainly altered in elderly and in cases with a
protruded type.
PMID- 9762160
TI - [Superficial cancer of the stomach: evolution of their characteristics over a 20
year period in one population].
AB - OBJECTIVES: The aim of this study was to analyse the incidence, treatment and
prognosis of early gastric cancer in a population-based series and to draw a
picture of time trends. METHODS: Over a 20-year period (1976-1995), 80 early
gastric cancers were diagnosed in the Cote-d'Or area (493,000 residents).
Incidence rates were calculated by sex, age groups and 5-year periods. Prognostic
factors were determined using the Kaplan-Meier method and the Cox model. RESULTS:
Age-standardized incidence rates were 0.8/100,000 in men and 0.3/100,000 in
women. Incidence increased slightly over time (NS) and their proportion among
gastric cancers increased from 3.4% (1976-1980) to 7.9% (1991-1995) (P < 0.01).
Among these cancers, 25 were intramucosal (31.3%), 55 were submucosal (68.8%) and
8 had lymph node metastases (10.0%). Overall 21 patients (24.1%) had already been
treated for a peptic ulcer. The 5-year crude survival rate was 63.1% and the
corresponding net survival rate was 86.3%. Lymph node metastases, location, sex
and cancer extension and age were independent prognostic factors. CONCLUSIONS:
Though it is on the increase, the proportion of early gastric cancers remains low
among gastric cancers. This study confirms the importance of performing a
gastroscopy with biopsy upon each bout of ulcer and that the prognosis is lower
than suggested by hospital based series.
PMID- 9762161
TI - [Are self-expanding metallic esophageal prostheses an effective treatment for
malignant stenosis of the esophagus? A prospective study of 32 cases].
AB - The treatment of esophageal carcinoma is frequently palliative. The aims of this
prospective study were to evaluate the functional results of covered self
expanding esophageal metal stents in patients with malignant obstruction of the
esophagus and to compare two models of stent. PATIENTS AND METHODS: From April
1994 to August 1996, 32 patients were treated with 35 metal stents (Cook Z Stent
Wilson Cook: n = 21; Ultraflex Boston Scientific: n = 14). Ten patients had a
fistula. Previous treatment was effective in 30 patients. Initial score of
dysphagia was 2.68 +/- 0.7. Initial score of Karnofsky was 60 +/- 10%. The metal
stents could be placed in 100% of cases. The 30-day mortality was 0%. The
morbidity of device placement of metal stents was 28%. The treatment of fistulas
was effective without complication in 100% of cases. At month 3, we observed a
significant decrease of dysphagia score (0.43 +/- 0.25) and a significant
increase of Karnofsky score (75 +/- 10%) (P < 0.001). The mean duration of
hospitalization was 5.4 +/- 1.3 days. During mean follow-up of 18 +/- 3.5 months,
14 patients (44%) died. Any difference concerning mortality and functional
results was observed between 2 kinds of metal stents. We only observed a
significant decrease of retrosternal pain in patients treated with Ultraflex
prothesis. CONCLUSION: Self-expanding esophageal metal stents are a simple and
effective palliative treatment of malignant obstruction of the esophagus.
However, their high cost need other cost-efficacy studies to define their
indications.
PMID- 9762162
TI - Plasma cholecystokinin and neurotensin after an ordinary meal in humans. A
prolonged time study.
AB - BACKGROUND/AIM: Ingestion of a meal causes the release of cholecystokinin and
neurotensin into the circulation, but little is known about the duration of this
release. METHODS: Six healthy volunteers were studied. Blood samples for
cholecystokinin, neurotensin and gastrin assessment were drawn before and after
consumption of a typical Italian lunch. Postprandial samples were obtained every
hour for a total of 10 hours. All peptides were measured using previously
validated radioimmunoassays. RESULTS: Ingestion of the meal caused a prompt and
significant increase in plasma levels of all three peptides. Cholecystokinin
remained elevated for about 7 hours and then tended to return towards basal
values, whereas the increase of neurotensin persisted for the entire period of
the study (10 hours). Gastrin remained elevated for about 5 hours and then
declined. The integrated CCK and gastrin responses during the initial
postprandial hours were greater than those in the late hours, whereas the
integrated neurotensin response during the initial hours was lower than that in
the late hours. CONCLUSIONS: The results indicate that, after an ordinary meal,
cholecystokinin is released into the circulation for about 7 hours, much longer
than previously reported (3-4 hours). The release of neurotensin begins soon
after the meal and persists even longer, for at least 10 hours. Possible
physiological implications of these findings are discussed.
PMID- 9762164
TI - [Hepatitic C in a prison environment: is screening necessary?].
PMID- 9762163
TI - [Randomized therapeutic trials in the treatment of acute pancreatitis: 1986
1996].
PMID- 9762165
TI - [Auto-immune cholangiopathies].
PMID- 9762166
TI - [Liver resection in patients with polycystic liver disease].
AB - OBJECTIVES: Polycystic liver disease is sometimes responsible for chronic
symptoms linked to hepatomegaly which can result in acute complications such
hemorrhage or infection of cysts. The aim of this retrospective study was to
evaluate the results of partial hepatic resection in patients with symptomatic or
complicated polycystic liver disease. METHODS: Twelve patients (11 women and one
man, mean age 49) with diffuse polycystic liver disease were treated by partial
liver resection (left lateral lobectomy in 7, left hepatectomy in 4, and extended
right hepatectomy in 1). Four patients had terminal renal failures and three had
chronic haemodialysis. Median follow-up was 34 months. RESULTS: Ascites occurred
postoperatively in 10 patients (83%) and was long-lasting (> 2 weeks) in 5; all
patients with end-stage renal failure had long-lasting ascites. One of them died
on the 40th postoperative day of ascites infection. Another patient with end
stage renal failure died two years postoperatively from chronic disabling ascites
and malnutrition while awaiting kidney transplantation. The 10 other patients
were markedly improved after partial liver resection, including a marked decrease
in hepatomegaly, and the disappearance of chronic symptoms and cystic
complications. This beneficial effect was incomplete in the two surviving
patients with end-stage renal failure until kidney transplantation was performed.
CONCLUSION: These results suggest that partial liver resection is a highly
effective treatment in patients with symptomatic polycystic liver disease,
preferably before the onset of end-stage renal failure.
PMID- 9762167
TI - [Infection with hepatitis C virus in a prison environment. A prospective study in
Loos-lez-Lille, France].
AB - OBJECTIVES: The aim of this study was to assess the prevalence of hepatitis C
virus (HCV) markers, and risk factors of contamination in a prison population.
PATIENTS AND METHODS: Eight hundred and six prisoners were prospectively
included, at the moment of their imprisonment, between December 1st 1995 and May
31st 1996. Each prisoner was included in a group "drug abusers" or "non drug
abusers" based on a clinical examination. Serum anti-HCV antibodies were tested
in each group. Other risk factors were also analysed (type of drug abuse, share
of syringes and needles, blood transfusion, haemodialysis, and hemophilia).
RESULTS: Among the 806 prisoners, 30.3% were anti-HCV positive. Four hundred and
thirty nine prisoners (54.4%) were placed in the "drug abuser" group and 367
(45.5%) in the "non drug abuser" group. In the first group, 55.6% were anti-HCV
positive (80% of the prisoners who were intravenous drug users and 10.8% for the
others) and 4.2% were anti-HCV positive in the second group. CONCLUSIONS: Half of
the prisoners entering our center were drug abusers and half were anti-HCV
antibody positive. HCV infection is a major public health problem in prison.
PMID- 9762168
TI - [Role of mitochondria in drug-induced hepatotoxicity].
PMID- 9762169
TI - [Role of sex steroids and their receptors in the pathophysiology of
hepatocellular carcinoma].
PMID- 9762170
TI - [Diagnosis of mediastinal neuro-endocrine tumor using endosonography guided
transesophageal puncture biopsy].
AB - Histologic diagnosis of tumors of the mediastinum is mandatory for therapeutic
management. The location and the variety of tumors are responsible for diagnostic
difficulties. Endosonography guided fine-needle biopsy is an efficient and safe
procedure for the diagnosis of peridigestive masses. We report the case of a
patient with a neuroendocrine tumor of the mediastinum revealed by a mass
syndrome. The diagnosis was performed by endosonography guided needle biopsy.
PMID- 9762172
TI - [Autoimmune cholangitis successfully treated with corticotherapy. One case].
AB - Autoimmune cholangitis is a rare cause of chronic liver disease which has
recently been described and associates the clinical, biological, and histological
patterns of primary biliary cirrhosis without serum anti-mitochondrial
antibodies. We report a case of this disease in a 67-year-old female. The patient
presented with jaundice and marked biological cholestasis associated with
pulmonary fibrosis and salivary and lacrymal sicca syndrome. Serum anti-smooth
muscle antibodies were found without anti-mitochondrial antibodies.
Corticotherapy resulted in rapid improvement of clinical and hepatic
abnormalities, as well as of pulmonary lesions. The patient was still healthy 18
months later, with low dose corticotherapy. This report emphasizes the possible
effectiveness of corticotherapy in autoimmune cholangitis.
PMID- 9762171
TI - [Benign intraductal papillary-mucinous tumors of the pancreas with a 30-year
follow-up].
AB - Intraductal papillary mucinous tumors of the pancreas are rare and characterised
by a malignant potential. Their natural history is unknown. We report a case of
intraductal papillary mucinous tumor of the pancreas, that was still benign
although the first symptom was appeared 30 years before the diagnosis. This case
report demonstrate the possible slow course of these tumors, for which malignant
degeneration is unpredictable.
PMID- 9762173
TI - [Diaphragm of cervical esophagus and autoimmunity].
PMID- 9762174
TI - [Vitamin C and diarrhea].
PMID- 9762175
TI - [Clostridium difficile pseudo-membranous colitic secondary to taking diclofenac].
PMID- 9762176
TI - [Intracystic biochemical and tumor markers in a case of pseudo-papillary and
solid tumor of the pancreas: pay attention to the interpretation].
PMID- 9762177
TI - [von Hippel-Lindau presenting as acute pancreatitis secondary to multiple
pancreatic cysts].
PMID- 9762178
TI - [Association of dermatomyositis and hepatocellular carcinoma. One case One case].
PMID- 9762179
TI - [Murderous impulses in two patients with chronic hepatitis C treated with
interferon alpha].
PMID- 9762180
TI - [Cibenzoline-induced acute hepatitis].
PMID- 9762181
TI - [Hemoperitoneum due to spontaneous splenic rupture: a rare complication of
primary cytomegalovirus infection].
PMID- 9762182
TI - [Meta-analysis or large randomized trial, that is the question].
PMID- 9762183
TI - [Hepatotoxicity of antituberculosis drugs: practical implications for
monitoring].
PMID- 9762184
TI - [Proposition of a code of ethics in clinical research].
PMID- 9762185
TI - [Percutaneous cholecystostomy. A study of 30 patients].
AB - OBJECTIVE AND METHODS: The treatment of acute cholecystitis or angiocholitis is
often difficult in elderly or very ill patients. The aim of this retrospective
study was to assess the efficacy and the results of ultrasound guided
percutaneous cholecystostomy in patients with acute cholecystitis or biliary
tract obstruction and anesthetic or surgical contraindications. RESULTS: Thirty
patients (25-93 years, 16 men and 14 women) were included in this study.
Ultrasound guided percutaneous cholecystostomy was successful on the septic
syndrome in 27 patients; endoscopic sphincterotomy was performed in 6 patients
after clinical improvement. A failure of the procedure on sepsis was observed in
3 patients: cholecystectomy was performed after cardiac improvement in one
patient, and 2 patients died. Two other patients died of extradigestive diseases.
No serious complication related to cholecystostomy was observed. CONCLUSION:
Ultrasound guided percutaneous cholecystostomy is a safe and simple procedure. It
can be done at bedside and has low morbidity and mortality. It can be considered
as a definitive treatment, or a temporary one with secondary surgical or
endoscopic management.
PMID- 9762186
TI - [Mechanisms of drug resistance in digestive tract cancer].
PMID- 9762187
TI - [Bile acid transport by the liver].
PMID- 9762188
TI - [Pancreatic cancer or chronic pancreatitis?].
PMID- 9762189
TI - [Diagnostic value of serum Ca 19-9 antigen in chronic pancreatitis and pancreatic
adenocarcinoma].
AB - OBJECTIVES: The value of serum Ca 19-9 dosage for pancreatic carcinoma diagnosis
has been studied in heterogeneous series. The effect of the complications of
chronic pancreatitis and pancreatic carcinoma on serum Ca 19-9 value has not been
assessed precisely. The aims of this study were to assess: a) the value of Ca 19
9 to differentiate benign from malignant pancreatic disease; b) the influence of
complications (particularly, cholestasis). METHODS: The studied population
included 179 patients: 126 with chronic pancreatitis (25 females, 101 males, 45
with cholestasis) and 53 with pancreatic carcinoma (27 females, 26 males, 37 with
cholestasis). RESULTS: At 37 UI/mL threshold, the specificity and sensitivity of
Ca 19-9 were 53 and 95%, respectively. Cholestasis was associated with a
significant increase of Ca 19-9 in patients with chronic pancreatitis but not in
those with pancreatic carcinoma. At 300 UI/mL threshold, the specificity and
sensitivity of Ca 19-9 were 95 and 81% in patients without cholestasis and 87 and
81% in those with cholestasis, respectively. Diabetes mellitus was associated
with a significant increase of Ca 19-9 only in patients with chronic pancreatitis
without cholestasis. Pancreatic calcifications, pseudocysts, cirrhosis, pleural
effusion or ascites were not associated with significant variation of Ca 19-9.
CONCLUSION: In patients with pancreatic disease, 300 UI/mL threshold is the most
accurate to differentiate benign from malignant disease, whatever the presence of
cholestasis.
PMID- 9762190
TI - [6-mercaptopurine levels and study of blood lymphocyte subsets during
azathioprine treatment of Crohn's disease].
AB - OBJECTIVES: Our aim was to study the relationships between clinical efficacy of
azathioprine, 6-mercaptopurine pharmacokinetics and changes in peripheral blood
lymphocyte subpopulations induced by azathioprine treatment in Crohn's disease.
METHODS: Twenty-three patients were prospectively followed up for 1 year.
Peripheral blood counts, total lymphocytes, CD3+, CD4+, CD8+, CD25+, CD16+CD56+,
CD57+ and CD19+ lymphocyte subpopulations were carried out, using flow cytometry,
during azathioprine treatment. Pharmacokinetic studies were performed at day 8
and month 3 by measuring 6-mercaptopurine plasma concentration after an oral dose
of azathioprine (2 mg/kg). Results were compared in responders (no activity and
no steroids) and non-responders. RESULTS: The decrease in peripheral blood
leukocytes and neutrophils was significant after 1 month, reaching 49% and 48% of
the pre-treatment values at 1 year; the one of lymphocytes was significant after
6 months and reached 41% at 1 year. Percentages of CD3+, CD4+, CD8+, CD57+,
CD16+CD56+ and CD19+ lymphocytes remained unchanged whereas percentage of CD25+
lymphocytes increased from 10% to 28% (P < 0.01). There was a high inter and
intraindividual variability of 6-mercaptopurine peak plasma concentration and
area under the curve. No significant difference was found between responders (n =
14) and non responders (n = 7) for pharmacokinetic parameters and lymphocyte
subpopulations; there was no correlation between lymphocyte subpopulation changes
and 6-mercaptopurine pharmacokinetics. CONCLUSION: Monitoring of 6-mercaptopurine
plasma concentration and blood lymphocyte subpopulations is of little value in
Crohn's disease patients treated with azathioprine.
PMID- 9762191
TI - [Prognostic factors in operable epidermoid esophageal cancers].
AB - OBJECTIVE: The aims of the study were to determine the prognostic factors on
overall survival in patients with resectable squamous cell esophageal carcinoma.
POPULATION: Two hundred and ninety three patients with stage I and II tumor were
included in a phase III clinical trial that compared surgery alone to
preoperative chemoirradiation. Eighteen parameters issued from clinical,
biological radiological and pathological characteristics were included in
univariate and multivariate analysis. RESULTS: The overall survival was
influenced by: quality of surgical resection tumor response, nodal involvement on
the CT-scan, tumor length and tumor location. Three groups of patients could be
identified on two simple clinical preoperative variables. The first group:
patients without dysphagia with or without nodal involvement on the CT-scan. The
second group: patients with dysphagia and without nodal involvement on the CT
scan. The third group: patients with dysphagia and with nodal involvement with CT
scan. The 5 years survival rates were 34% for the first group, 23% for the second
group and 0% for the third group. CONCLUSION: The identification of prognostic
factors is valuable for the stratification of patients in future therapeutic
studies.
PMID- 9762192
TI - [Crohn's disease and blood vessels].
PMID- 9762193
TI - [Consensus conference. Prevention, diagnosis and treatment of colon cancer].
PMID- 9762195
TI - [Adult idiopathic ductopenia. 1 case].
AB - Idiopathic adult ductopenia is very rare. We report one case in a 30-year-old
man, whose clinical course was characterized by jaundice and pruritus. Laboratory
investigations revealed cholestasis and polyclonal hypergammaglobulinemia. Serum
antinuclear, antimitochondrial, and anti-smooth muscle antibodies and serological
markers for viral hepatitis were negative. Endoscopic retrograde cholangiography
showed no liver or biliary tract abnormalities. Histological examination of a
liver specimen showed a vanishing bile duct syndrome and moderate portal
infiltration with lympho-histiocytic cells; there were no granulomas. Liver
transplantation was performed due to rapid development of cirrhosis. The
differential diagnosis of idiopathic adult ductopenia with small duct primary
sclerosing cholangitis, auto-immune cholangiopathy, and non syndromic paucity of
intrahepatic bile ducts is unclear.
PMID- 9762196
TI - [Severe hemorrhagic gastritis of radiation origin].
AB - Severe gastric complications due to radiotherapy are uncommon, in particular
hemorrhagic gastritis. A high total dose and, above all, high daily fraction
appear to be the main risk factors in gastric injuries. A case of hemorrhagic
gastritis induced by radiotherapy requesting a total gastrectomy is reported. The
patient was treated for a primary gastric non-Hodgkin's lymphoma. Hemorrhagic
gastritis occurred despite a low total dose (40 Gy) and 2 Gy daily fractions.
Upper gastrointestinal endoscopy and repeated biopsies are usually insufficient
to exclude a tumor recurrence. Endoscopic ultrasonography may argue for a
recurrence or for radiation lesions. As the conservative treatment is usually
ineffective, these gastrointestinal radiation injuries ought to be treated
surgically. Besides it allows to ascertain the benign nature of radiation
lesions.
PMID- 9762197
TI - [A case of digestive epilepsy with late diagnosis: a disease not to be
disregarded].
AB - Digestive epilepsy is a rare disease, poorly recognized by gastroenterologists.
Its diagnosis requires a compatible clinical presentation, the absence of
concomitant organic digestive disease, and an effective and long-lasting response
to specific anticonvulsant agents. We report a case of digestive epilepsy due to
a meningioma of the right parietal lobe in a 79-year-old woman suffering from
headaches, vertigo, sweating and abdominal pain for at least 14 years. Initial
diagnosis was irritable bowel syndrome. A meningal syndrome led to neurological
work-up showing cerebral meningioma. The recurrent paroxysmal abdominal pain was
interpreted as manifestations of digestive epilepsy, and effective and long
lasting treatment was obtained with carbamazepine. After analysis of the
determining elements in this case, the epidemiology, pathophysiology, diagnostic
work-up, therapy, and differential diagnosis of digestive epilepsy are discussed.
PMID- 9762198
TI - [The synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome, a rare
extra-digestive manifestation of Crohn's disease. Presentation of 1 case and
review of the literature].
AB - We report the case of a 33-year-old man with a severe Crohn's disease since the
age of sixteen. He presented with acne and palmoplantar pustulosis associated
with a right knee synovitis. Investigations revealed a major axial bone
condensation. The association synovitis-acne-pustulosis-hyperostosis-osteitis
leaded to the diagnosis of SAPHO syndrome associated with Crohn's disease.
PMID- 9762199
TI - [Cost of hemostatic treatment of hemorrhage due to esophageal varices rupture].
PMID- 9762200
TI - [Acute autochtonus hepatitis E in Lorraine].
PMID- 9762201
TI - [Hepatocellular carcinoma complicating agenesis of the portal vein].
PMID- 9762202
TI - [Retrogastric abscess secondary to gastric varices obturation with
cyanoacrylate].
PMID- 9762203
TI - [Severity of Hirschsprung's disease in the adult].
PMID- 9762204
TI - [Pneumopericardium and drug-induced ulcer in an intrathoracic Nissen
fundoplication].
PMID- 9762205
TI - [Primary melanoma of the small intestine].
PMID- 9762206
TI - [Opiod antagonists and treatment of cholestatic pruritus].
PMID- 9762207
TI - [Proctology teaching: impossible reality? Creation of a Complementary Special
Study Diploma of Medico-surgical Proctology].
PMID- 9762208
TI - [What is the role of endo-rectal echography in monitoring of patients operated on
for rectal cancer?].
PMID- 9762209
TI - [Adjuvant chemotherapy for colon adenocarcinoma in the county of Cote-d'Or].
AB - OBJECTIVES: The aim of this study was to assess the use of adjuvant chemotherapy
in colon adenocarcinomas on a population basis and determine which factors could
modulate its prescription. METHODS: The influence of time of diagnosis, age, sex,
place of residence, health care pattern, tumor location and number of metastatic
lymph nodes was investigated from the 1988 to 1995 data from the Registry of
Digestive Cancers in Cote-d'Or (France). Each independent variable was given an
odds-ratio (OR). RESULTS: An adjuvant chemotherapy was performed for 0.9% of 231
Dukes'A cancers, 3.8% of 367 Dukes'B and 16.7% of 264 Dukes'C. For the latter,
the prescription of adjuvant chemotherapy was influenced by time of diagnosis
(from 1.3% in 1988-89 to 35.8% in 1994-95; OR = 228 for period 1994-95 compared
with the first period), age (the proportion of treated patients under 75 years of
age has increased from 2.2% in 1988-89 to 57.9% in 1994-95; OR = 30.1 for
patients younger than 75 years compared with older ones) and health care pattern
(OR = 0.21 for treatment in non university hospitals and 0.06 in the private
sector compared with university hospitals. CONCLUSION: In spite of an increasing
proportion of patients treated by adjuvant chemotherapy for Dukes'C colon
cancers, this treatment of proved effectiveness has not yet reached its full
development.
PMID- 9762210
TI - [Cisplatin, 5-FU and preoperative radiotherapy in esophageal epidermoid cancer.
Multicenter phase II FFCD 8804 study].
AB - OBJECTIVES: The aim of this study was to analyze the efficacy and tolerance of
preoperative radiochemotherapy in esophageal squamous cell carcinoma. Patterns of
recurrence and prognostic factors were also studied. PATIENTS AND METHODS: This
multicentric phase II trial included patients deemed operable. Preoperative
treatment associated 5-FU 800 mg/m2/d by continuous infusion, cisplatin 20
mg/m2/d and radiotherapy 3 Gy/d D 1-5 and D 22-26. Resection was planned 50 to 60
days after the beginning of therapy. RESULTS: Seventeen centers accrued 96
patients, mean age 55.4 years. According to UICC 1978 classification: stage I
13%, stage II 53% and stage III 30%. Mean follow-up was 73 months. Pre-operative
treatment was delivered at full dose in half of the patients. Ten percent of the
patients did not receive the second cycle. Toxicity reached grade 3 in 23% and
grade 4 in 7% of the patients. Two preoperative deaths occurred. Curative
resection was performed in 82% of the patients. Operative mortality was 9%.
tumors were sterilized on the operative specimen in 20% of the patients and
microscopic remnants were observed in 13%. Preoperative clinical work-up
overestimated histologic response in 10% of the cases underestimated it in 29%.
After 2 years, a recurrence was observed in 56% of the patients: loco-regional in
30%, metastases in 19% and both in 7%. Median survival was 17 months and survival
rates were 58% at 1 year and 25% at 5 years. Four prognostic factors influenced
survival in multivariate analysis (Cox model): hematological toxicity grade 3 or
4, no complete response, circumferential extension > 2/3 and nodes visible on CT
scan. Factors positively influencing complete response were in multivariate
analysis: a fungating tumor, weight loss < 8% and a full dose preoperative
treatment. CONCLUSION: In this study, preoperative treatment associating 5-FU
cisplatin and radiotherapy allowed a high resectability rate, with one third of
patients achieving complete or nearly complete histologic response. A randomized
study is warranted to know whether this combined treatment is better than surgery
alone.
PMID- 9762211
TI - [When should patients with bleeding peptic ulcer resume oral intake? A randomized
controlled study].
AB - OBJECTIVES: Patients presenting with bleeding peptic ulcers are often kept
fasted. The contribution of feeding in bleeding recurrence rate is unknown. The
aim of this prospective controlled study was to evaluate the effect of early
feeding in (a) the bleeding peptic ulcer recurrence rate and (b) the outcome of
patients with severe bleeding peptic ulcer. PATIENTS-METHODS: From January
through December 1995, all consecutive patients admitted for active bleeding from
peptic ulcer were included. All patients underwent emergency endoscopic injection
with adrenaline around and into the base of the ulcer and were randomized in two
groups. Group A patients (n = 12) received milk on day 1, mixed warm feeding on
day 2 and normal diet from day 3, Group B patients (n = 14) were nil by mouth
until day 3, then received milk on day 4, mixed warm feeding on day 5, and normal
diet from day 6. Twenty-six patients (17 men, 9 women, mean age 71 years) were
included. RESULTS: On day 0, both groups (group A vs group B) were comparable
(mean +/- SD): hemoglobin (8.8 +/- 2.7 vs 8.1 +/- 2.0 g/dL), transfusion
requirements in the first 24 h after admission (2.2 +/- 2.0 vs 2.1 +/- 1.4
units), localization of ulcers (duodenal ulcer: 8 vs 9, gastric ulcer : 4 vs 5).
There were no significant differences in group A and group B for bleeding ulcer
recurrence rate (0 vs 1 patient) and transfusion requirements (2.6 +/- 2.1 vs 3.3
+/- 2.1 units). Hospital stay was significantly shorter in group A (6.8 +/- 2.1
days) than in group B (9.9 +/- 3.7 days), P = 0.01. CONCLUSION: These results did
not provide any evidence of advantages of fasting in patients with active
bleeding peptic ulcer treated by endoscopic sclerotherapy. Early feeding did not
worsen outcome in patients with active bleeding peptic ulcer and reduced hospital
stay.
PMID- 9762212
TI - [Surgical morbidity of segmental colectomy ideally performed via laparotomy for
complicated colonic diverticulosis].
AB - OBJECTIVES: The appraisal of morbidity and mortality for one stage elective
colectomy for complicated diverticulosis is difficult and often overestimated,
due to the rarity of reports addressing this question. Our results for 100
patients on a recent 30 month period were studied retrospectively. METHODS: One
hundred patients were electively operated in a one-stage procedure for
complicated diverticulosis in a single institution from January 1993 to June
1995. There were 66 females and 34 males (range: 31-81 years) with a mean age of
61 years. Main indications for surgery were repeated attacks (34 patients),
chronic inflammatory mass (26 patients) and stenosis (22 patients). Seventy-eight
patients had already been admitted for diverticulitis prior to surgery. There
were 13 surgeons including 6 seniors and 7 fellows. RESULTS: There was no
mortality. Morbidity was 14% surgical and medical complications accounting for 8%
and 6% respectively. One patient had an anastomotic fistula treated
conservatively and another patient was reoperated on for early postoperative
occlusion There was no perioperative bleeding requiring transfusion. There were
no surgical trauma of spleen or uretera. Mean hospital stay was 10 days.
CONCLUSION: This study of a collective surgical experience demonstrates that
elective one stage left colectomy for benign disease is safe, without mortality
and with low morbidity.
PMID- 9762214
TI - [Clinical and Biological Gastroenterology: evaluation of Hepatology division,
1995 to 1997].
PMID- 9762213
TI - [Cholesterol crystal embolization in the digestive tract].
PMID- 9762215
TI - [Antibiotic prophylaxis of ascitic fluid infection].
PMID- 9762217
TI - [Pro-inflammatory cytokines in the pathogenesis of alcoholic hepatitis].
PMID- 9762216
TI - [Adult multi-nuclear cell hepatitis. A study in 17 patients].
AB - OBJECTIVES: Giant-cell hepatitis is rare in adults and its significance has not
been clarified. We report the clinical and histological characteristics and
outcome in a group of adult patients with giant-cell hepatitis. METHODS:
Seventeen patients with giant-cell hepatitis, hospitalized in our unit between
1976 and 1992, were studied retrospectively. Giant-cell hepatitis was defined as
at least two hepatocytes with four or more nuclei per cell on liver biopsy.
Clinical and biochemical parameters, liver histology, and the serological profile
of HAV, HBV, HCV, HIV, HSV, EBV, CMV, and paramyxovirus were evaluated.
Paramyxovirus immunochemistry was performed in 6 liver biopsies. RESULTS: There
were 11 females and 6 males, an average of 48 years old (range: 29-80). Four
patients had a well-defined etiology: acute hepatitis B infection with a
favorable outcome in 2 cases, clometacine induced-hepatitis resulting in death
from liver failure in one case, and chronic hepatitis B and C in one patient with
AIDS. Among the 13 patients in which the etiology could not be determined,
histologically defined acute hepatitis was observed in 8 and chronic hepatitis in
5. Nine patients were treated with immunosuppressive drugs. One patient was lost
to follow-up. Eight patients responded to treatment, but 5 patients progressed to
cirrhosis between 5 months and 7 years. Two of the 4 patients with unexplained
liver disease who did not receive any treatment died of liver failure.
CONCLUSION: In patient with acute or chronic hepatitis without an identified
cause (with or without autoimmune abnormalities), the presence of giant-cell
hepatitis seems to have a similar evolution as active autoimmune hepatitis. The
poor prognosis of these patients suggests that early immunosuppressive treatment
is justified.
PMID- 9762218
TI - [MRI cholangiopancreatography].
PMID- 9762219
TI - [Abdominal echography (pelvis excluded) as first approach: indications. Working
Group of the National Accreditation and Health Evaluation Agency].
PMID- 9762220
TI - [Abdominal emergencies in type IV ehlers-Danlos syndrome].
AB - Ehlers-Danlos syndrome denotes a group of inherited connective tissue diseases
comprising nine types. Type IV Ehlers-Danlos syndrome is the most life
threatening form. It is characterized by a type III collagen deficiency resulting
in arterial fragility and death from vascular rupture or bowel perforation. This
disease involves a col 3A1 gene mutation. We report the case of a 44 year-old
woman with type IV Ehlers-Danlos syndrome. The medical history of our patient
included bowel necrosis and two vascular ruptures. We indicate data required to
establish Ehlers-Danlos syndrome diagnosis and guidelines for patient management.
PMID- 9762221
TI - [Paraneoplastic intestinal pseudo-obstruction revealing small cell lung
carcinoma: "the anti-Hu syndrome"].
AB - A 67-year-old woman was admitted for intestinal pseudoobstruction associated with
peripheral sensitive neuropathy. Jejunal biopsies performed during laparotomy,
showed axonal degeneration and lympho-plasmocytic infiltration in myenteric
plexus. High titer of seric anti-Hu antibodies suggested a paraneoplastic
syndrome. Thoracic CT scan showed mediastinal lymph nodes. Their histological
examination confirmed the diagnosis of metastatic small-cell lung carcinoma. Her
condition gradually deteriorated despite supportive parenteral nutrition,
chemotherapy, steroids and intravenous immunoglobulins. She died 12 months after
the onset of symptoms.
PMID- 9762222
TI - [Cap polyposis: a rare syndrome].
AB - We report a case of inflammatory cap polyposis of the colon, a rare syndrome,
affecting the rectosigmoid. It was observed in a context of mucous diarrhea.
Endoscopic and radiological features consisted of elevated and umbilicated
nodular lesions. Histology revealed polypoid lesions containing elongated crypts
with superficial abrasions, covered by inflammatory and fibrinoid material.
Etiopathogenesis of this new syndrome is unknown.
PMID- 9762223
TI - [Suicidal impulses in patients with chronic viral hepatitis C during or after
therapy with interferon alpha].
AB - We report 5 cases of psychiatric side effects in patients treated with alpha
interferon for chronic viral C hepatitis. The first case includes depression with
suicidal impulses without a suicide attempt; there was a positive rechallenge of
interferon. In the second and third cases, depression occurred during interferon
therapy, but has not disappeared after interferon withdrawal. In the 4th and 5th
cases, depression occurred after interferon withdrawal. Overall, suicide was
attempted in 4 cases after interferon withdrawal and was responsible for 2
deaths. The prevalence of suicide attempts during the 6 to 12 months of
interferon therapy was 0% compared to 1.3% during the 6 months after interferon
therapy (P < 0.05) in 306 patients with chronic hepatitis C treated by interferon
in our local area network during the same period. IN CONCLUSION: a) depression
does not always disappear after interferon is discontinued; b) regular
psychiatric follow-up is justified during treatment with interferon; c)
psychiatric supervision should be continued, even more frequently after
interferon withdrawal; d) the increased risk of psychiatric side-effect due to
interferon as well as their severity suggest interferon should be administered
with caution; e) the role of interferon can only be evaluated in controlled
studies including the incidence and predictive value of emotional disorders.
PMID- 9762224
TI - [Probable choroid metastasis of an esophageal adenocarcinoma that regressed with
chemotherapy].
PMID- 9762225
TI - [Perineal anaerobic necrotizing cellulite after preoperative radiotherapy for
rectal cancer].
PMID- 9762226
TI - [Lymphocytic colitis and ticlopidine].
PMID- 9762227
TI - [Lymphocytic colitis likely attributable to use of vinburnine (Cervoxan)].
PMID- 9762228
TI - [Veno-occlusive disease after prolonged treatment with senecionine (Hemoluol)].
PMID- 9762229
TI - Symptomatic liver injury probably related to sertraline.
PMID- 9762230
TI - [Colonic cancer: why have a consensus conference in 1998?].
PMID- 9762231
TI - [Colonic cancer: descriptive epidemiology and high-risk groups].
PMID- 9762232
TI - [Diet and colorectal carcinogenesis: clues for primary prevention].
PMID- 9762233
TI - [Do aspirin or nonsteroidal anti-inflammatory drugs decrease the risk of
colorectal cancer?].
PMID- 9762234
TI - [Conditions necessary for carrying out a screening program].
PMID- 9762235
TI - [Colorectal cancer screening. Present status in France].
PMID- 9762236
TI - [Strategy of screening for patients at high risk of colorectal neoplasm].
PMID- 9762237
TI - Screening for colorectal cancer with Hemoccult-II in the average risk population.
PMID- 9762238
TI - [What are the costs of an efficient screening strategy for colonic cancer?].
PMID- 9762239
TI - [Consequences of legal medicine in incidence of colonic cancer screening].
PMID- 9762240
TI - [Colonic cancer screening: legal aspects of organization and liability].
PMID- 9762241
TI - [Colonic cancer: change in circumstances and techniques of diagnosis in France
between 1990 and 1995].
PMID- 9762242
TI - [Which explorations are useful for colonic cancer diagnosis?].
PMID- 9762243
TI - [Pretherapeutic evaluation of colonic cancer].
PMID- 9762244
TI - [Therapeutic management of colonic cancer in France].
PMID- 9762245
TI - [What are the modalities of elective surgery for colonic cancer? Which items are
to be included in the operative report?].
PMID- 9762246
TI - [Emergency management for colonic cancer].
PMID- 9762247
TI - [Prognosis of colonic cancer in population based studies].
PMID- 9762248
TI - [What histo-prognostic factors are useful in making a therapeutic decision in
colonic cancer?].
PMID- 9762249
TI - [Recommendations for pathologic reporting of resected colonic neoplasms].
PMID- 9762250
TI - [Which adjuvant treatments and what are their indications following resection for
cure in colonic cancer?].
PMID- 9762251
TI - [Management of malignant polyps].
PMID- 9762253
TI - [Should a recurrence be searched for in colonic cancer patients resected for
cure? If so, by what means?].
PMID- 9762252
TI - [Which endoscopic follow-up for resected colonic cancer?].
PMID- 9762254
TI - [Colonic cancers with visceral metastasis (synchronous or metachronous): which
surgical treatment to offer?].
PMID- 9762255
TI - [Colonic cancers: which surgical treatment should be proposed for extra-colonic
invasion and locoregional recurrence?].
PMID- 9762256
TI - [Chemotherapy in locally advanced or metastatic colonic cancer].
PMID- 9762257
TI - [Diet and nonsteroidal anti-inflammatory drugs: role in prevention of colorectal
cancer].
PMID- 9762258
TI - [Is colorectal cancer screening feasible and useful?].
PMID- 9762259
TI - [Which techniques are useful for diagnosis of colonic cancer and for therapeutic
choice?].
PMID- 9762260
TI - [What are the standards of curative surgical treatment of colonic cancer?
Scheduled and emergency surgical procedures. Prognostic factors helpful for
therapeutic decision making].
PMID- 9762261
TI - [What should be done after curative surgery for adenocarcinoma of the colon?].
PMID- 9762262
TI - [Position of adjuvant and palliative chemotherapy in colonic cancer treatment].
PMID- 9762263
TI - [Surgical treatment of locally advanced and/or metastatic colonic cancers].
PMID- 9762265
TI - [Hepatocellular carcinoma in the non-cirrhotic liver: renewed interest].
PMID- 9762266
TI - [Epidemiology of hepatitis C virus infection in 1,304 HCV positive patients:
variations according to the origin of transmission and year of diagnosis].
AB - The evolution of epidemiological data on hepatitis C virus infection is poorly
documented and thus the impact of screening is difficult to evaluate. AIM: To
study epidemiological variations based on the origin of transmission and the year
of diagnosis of hepatitis C virus infection. METHODS: The files of all 1304
patients seen in the hepatology unit of the Rennes University Hospital were
analyzed (retrospectively before and prospectively after October 1995) in
relation to epidemiological features. RESULTS: Despite widespread screening which
is the source of 60% of the diagnoses, the total number of new cases of hepatitis
C infection per year has not increased. Compared to patients diagnosed in the
first years following the discovery of the virus, patients recently identified
were younger (42 +/- 14 years) and frequently drug addicts (40%).
Aminotransaminases were normal in 20% of cases. The frequency of cirrhosis has
declined (17%). There has been a decrease in the proportion of patients who
undergo liver biopsy (50%) and treatment with interferon (one third of patients).
CONCLUSIONS: The impact of screening on the number of newly treated patients
seems to be lower than previously predicted.
PMID- 9762267
TI - [Apoptosis in normal and diseased liver].
PMID- 9762268
TI - [Duplex Doppler sonography of splanchnic circulation in man. Clinical and
physiological importance].
PMID- 9762269
TI - [Diagnosis of Helicobacter pylori infection is still a timely issue].
PMID- 9762270
TI - [Comparison of quantifying Helicobacter pylori gastric infection by culture,
histology and C13 urea breath test].
AB - OBJECTIVES: In Helicobacter pylori infection, the bacterial burden may play a
role in the pathogenesis of gastric or duodenal ulcerated lesions. It could also
influence the results of antimicrobial therapy. No simple test has been validated
to quantify Helicobacter pylori density. The aim of this study was to determine
the value of histology and/or 13C-urea breath test to quantify the infection as
compared with quantitative culture, taken as a reference method. PATIENTS AND
METHODS: Biopsies samples were taken from the antrum at endoscopy in 72 patients.
Thirty-seven patients with positive urease test at 20 minutes were enrolled in
the study. Bacterial density was evaluated from biopsies by quantitative culture
and semi-quantitative histological examination (score from 0 to 3). The bacterial
density was evaluated as well by 13C-urea breath test from the proportion of
13CO2 in exhaled air (delta 13CO2) at 20, 40, and 60 minutes as compared with the
basal level. RESULTS: The bacterial density, evaluated by quantitative culture
ranged from 5 CFU to 110,000 CFU per mg of tissue. By histology, a score 1 was
found in 5 patients, a score 2 in 17, and a score 3 in 15. delta of 13CO2
measured by 13C-urea breath test ranged from 0.2 to 117.5, from 0.2 to 102, and
from 0.6 to 66.7 at 20, 40 and 60 minutes respectively. The quantity of bacteria
measured by culture was not significantly higher for these with a score of 3 as
compared with those with a pooled score of 1 and 2 (P < 0.05). No significant
correlation was found between the results of quantitative culture and these of
breath test. CONCLUSION: In practice, evaluation of bacterial burden by a
histological score seems only accurate for the most severe density (score 3). The
13C-urea breath test does not allow a reliable quantitative evaluation.
PMID- 9762271
TI - [A 1993-1995 epidemiological survey of home parenteral nutrition in approved
centers for adults in France].
AB - OBJECTIVES: A 1993-1995 three year epidemiological survey of home parenteral
nutrition was performed through in France in approved centers for adults.
METHODS: Data were retrospectively collected each year on a standardized
questionnaire focussing on indications and short term outcome. RESULTS: All
centers (n = 14) participated in the study and 524 new adult patients were
recruited. The overall incidence was unchanged at 3.75 patients/10(6) adults.
Indications for AIDS rose (8 to 18%) whereas other indications were stable.
Prevalence increased by 19%: 4.40 adults/10(6) patients at 01.01.1996. At six
months, the probability to stay on treatment was 19.5% for AIDS and cancer
indications but 52% for others, whereas death rates were 59% and 9% respectively.
CONCLUSIONS: For both cancer and AIDS indications, short-term treatment was due
to a poor prognosis. For other diagnosis, complicated with a short bowel in 51%
of cases, prognosis was excellent but associated with treatment dependency. The
latter point focuses on the need for additional treatments in irreversible
intestinal failure.
PMID- 9762272
TI - [Use of a medium and long chain triglyceride mixture for parenteral nutrition in
a university hospital: results of an internal audit].
AB - OBJECTIVES: The aim of this study was to determine whether a medium and long
chain triglyceride mixture for parenteral nutrition is used in accordance with
indications and contraindications in hospital practice. METHODS: Patient data
recorded in 30 consecutive patients included illness, nutritional status,
laboratory findings before nutrition as well as indications and contraindications
for parenteral nutrition. RESULTS: When expressed in g.kg-1.day-1 maximal
recommended doses of the mixture were exceeded in 32% but there was no excess
when expressed in g.kg-1.hr-1. Serious hepatic insufficiency was present in 11%
of the patients, 38% had hypertriglyceridemia and one had serious coagulopathy.
There were 3 contraindications for the mixture. CONCLUSION: Indications for using
this emulsion were respected, but there were contraindications in 45% of the
cases. These contraindications are however questionable as is the daily dosage.
Because the mixture seems better for use in many cases of parenteral nutrition,
it would appear best to discuss the prescription case by case.
PMID- 9762273
TI - [Colonic polyps considered unresectable by endoscopy. Removal by combinations of
laparoscopy and endoscopy in 65 patients].
AB - OBJECTIVE: To determine to what extent segmental colectomy could be avoided in
patients with polyps though to be endoscopically unresectable by using
combination laparoscopy and endoscopy. METHODS: Sixty-five patients referred for
colonic polyps though to be unresectably by conventional endoscopy were studied.
After analysis of the endoscopic findings, endoscopy was performed in a
medicosurgical unit when possible, otherwise a surgical procedure was performed
consisting of laparoscopy followed by colonoscopy. Therapeutic strategy depended
on laparoscopic and endoscopic findings. RESULTS: Segmental colectomy was avoided
in 44 patients (67.7%). Among them, 20 were treated by simple endoscopic polyp
removal, 12 by laparoscopy-assisted colonoscopic polypectomy, 9 by laparoscopic
wedge colonic resection and 3 by colotomy after colonic exteriorization and polyp
resection. Laparoscopic or laparoscopy-assisted segmental colectomy was performed
in 16. Segmental colectomy by laparotomy was necessary in 5. No complication
occurred. CONCLUSION: Segmental colectomy for unresectable colonic polyps could
be avoided in more than half of the patients using laparoscopy and colonoscopy
combinations.
PMID- 9762274
TI - [Microscopic colitis].
PMID- 9762275
TI - [Serum markers for breast and colorectal cancers. Working group reunited by the
National Health Agency for Accreditation and Evaluation (NHAAE)].
PMID- 9762276
TI - [Massive hepatic necrosis secondary to treatment of hepatocellular carcinoma by
percutaneous alcoholization].
AB - Fatal complications of percutaneous ethanol injection for the treatment of
hepatic tumors are rare events. We report a case of massive hepatic necrosis
after treatment by percutaneous ethanol injection of a 4 cm diameter
hepatocellular carcinoma, which resulted in the death of the patient. The
mechanism of this complication was probably an intratumoral aterioportal shunt,
which allowed ethanol to spread through the blood vessels.
PMID- 9762277
TI - [Duodenal hematoma, acute pancreatitis, and hemoperitoneum after endoscopic
hemostasis for duodenal ulcer].
AB - Therapeutic endoscopy is followed by complications in less than 5% of cases. We
report a case of an intramural duodenal hematoma after local endoscopic injection
of 28 mL of adrenaline 1/10,000 for a bleeding duodenal peptic ulcer. This
hematoma was associated with acute pancreatitis and was revealed by a
hemoperitoneum.
PMID- 9762278
TI - [Extension of an acinar cell pancreatic carcinoma with cystic changes invading
the Wirsung canal].
AB - We report a case of acinar cell carcinoma of the pancreas with misleading cystic
changes. A 32-year-old woman presented with symptoms suggesting acute
pancreatitis on chronic pancreatitis. The abdominal computed tomography and the
endoscopic retrograde pancreatography demonstrated hypertrophy of the pancreatic
head associated with global dilatation of main pancreatic duct and secondary
canals and a 5 cm communicating cyst. A intraductal papillary-mucinous tumor was
suggested. Microscopic findings showed a poorly differentiated adenocarcinoma.
Six months later, a liver metastasis was detected. The microscopic appearance was
different, suggesting acinar cell carcinoma, confirmed by immunohistochemistry.
Only two other cases of acinar cell carcinoma with cystic component have been
reported in the literature.
PMID- 9762279
TI - [Hepatitis C virus reinfection after an intravenous drug injection].
PMID- 9762280
TI - [Umbilical metastasis of an hepatocellular carcinoma].
PMID- 9762281
TI - [Diffuse colon linitis secondary to a gastric adenocarcinoma. Detected during
diarrhea treated with octreotide].
PMID- 9762282
TI - [Acute anorectal lesions after a hot-water enema].
PMID- 9762283
TI - [Ticlopidine, diarrhea and lymphocytic colitis].
PMID- 9762284
TI - [Ano-perineal endometriosis with external sphincter involvement: a rare
disorder].
PMID- 9762285
TI - [In which circumstances is push-type video-enteroscopy really useful?].
PMID- 9762286
TI - [Comparison of push-type endoscopy and barium transit study of the small
intestine in digestive bleeding and unexplained iron-deficiency anemia].
AB - OBJECTIVES: A radiological examination of the small bowel is often performed in
case of gastrointestinal bleeding of obscure origin. More recently, push-type
enteroscopy has been reported as a valuable tool in this indication. The purpose
of this study was to compare the diagnosis efficiency of these two procedures.
METHODS: From February 1994 to February 1996, 40 patients (mean age: 52 years)
with obscure gastrointestinal bleeding (iron-deficiency anemia without obvious
cause of blood loss or malabsorption: n = 17; macroscopic gastrointestinal
bleeding: n = 23) were examined by small bowel follow-through and push-type
enteroscopy (jejunoscopy n = 19; double way examination n = 21). Each patient had
negative upper and lower gastrointestinal tract endoscopies prior to small bowel
examinations. RESULTS: Small bowel follow-through revealed only one lesion
potentially responsible for blood loss (2.5%), corresponding to a jejunal
leiomyoma. Push-type enteroscopy detected small bowel lesions potentially
responsible for blood loss in 6 patients (15%). The lesions were located in the
jejunum in 5 cases (arteriovenous malformations: n = 3; metastasis: n = 1;
leiomyoma: n = 1), in the ileum in 1 case (leiomyoma). The efficiency of push
type enteroscopy for the detection of a small bowel lesion was of 22% in case of
macroscopic bleeding and of 6% in case of iron-deficiency anemia. Push-type
enteroscopy also revealed lesions previously undetected by gastroscopy or
colonoscopy in 8 patients (20%). CONCLUSION: Push-type enteroscopy was more
effective than small bowel follow-through to detect the origin of obscure
gastrointestinal bleeding. Push-type enteroscopy revealed a cause of bleeding in
35% of patients, located in the small bowel in only 15% of the patients.
PMID- 9762287
TI - [Gene p53 mutations and overexpression of p53 protein in tumors of the Vater's
ampulla].
AB - OBJECTIVES AND METHODS: New prognostic markers for tumors of the ampulla of Vater
which could distinguish aggressive lesions would be highly useful. The aim of
this study was to evaluate the abnormal expression of p53 protein in a series of
34 ampullomas with the monoclonal antibody DO7 directed against p53 protein.
Mutations of exons 5 to 8 of p53 gene were also detected by PCR followed by
denaturating gel electrophoresis and sequencing. RESULTS: One of 5 adenomas (20%)
and 16 of 29 adenocarcinomas (55%) were p53 positive by immunohistochemistry. A
constant feature was the presence of p53 positive glands in the surrounding
dysplastic mucosa of p53 positive infiltrative lesions. There was no correlation
between p53 immunostaining and tumor stage. Among the 19 tumors analyzed, 6
mutations were detected. CONCLUSION: p53 gene mutations and p53 protein
immunoreactivity are frequently present in ampullomas. Because these alterations
are not correlated to tumor extension and occur at an early stage in the
carcinogenesis, their detection does not appear to be contributive for diagnosis
of ampullary tumors.
PMID- 9762288
TI - [Therapeutic approach of French practitioners to rectal cancer].
AB - OBJECTIVES: Improvements in treatment of rectal cancer have enabled a better
control of locoregional disease. Our objective was to describe the therapeutic
decisions of different specialists implied through clinical cases and the
influence of their professional characteristics. METHODS: In spring 1996, a
questionnaire was mailed to a random sample of 621 French physicians, presenting
3 clinical cases of rectal cancer at different stages. The present analysis deals
with a clinical case concerning a 46 year-old man bearing a T3N0 tumor, at 7 cm
from the anal verge. Statistical analysis (uni and multivariate, by logistic
regression) was performed with SPSS software. RESULTS: Three hundred fifty two
exploitable responses were returned (response rate: 57%). Half of the physicians
chose a pluridisciplinary decision modality. There were differences according to
the speciality (P < 0.003), to the type of practice (public/private) (P < 10(-4))
and to the proximity of specialized units (P = 0.03). Therapeutic attitudes
consisted in a combination of radiotherapy and surgery (RT-SU) for 95% of the
physicians. The therapeutic choice was in agreement with the French consensus
conference for 71% of physicians. Two main attitudes emerged for this clinical
case: exclusive RT-SU combination (43.5%) and RT-SU with optional or systematic
chemotherapy (CT) (52%). The latter choice appeared to be closely dependent on
medical speciality (P = 0.0004) and background (P = 0.002). CONCLUSION: Decision
making is mainly related to the place of work, whereas the therapeutic attitude
depends on physicians' own characteristics. Until 1990, multiple therapeutic
options for rectal cancer were performed in France. Nowadays, for a T3N0 tumor,
the argumentation is rather focused on the indication of CT combined with the
standard RT-SU treatment. Results from ongoing controlled studies will help
update consensual recommendations.
PMID- 9762289
TI - [Intestinal inflammation and motility].
PMID- 9762290
TI - Predictive factors of variceal bleeding control by emergency sclerotherapy.
Multicenter Group.
AB - OBJECTIVES: Acute bleeding from esophageal varices is a major complication of
cirrhosis. Despite the large number of published studies no predictive factors of
control of bleeding have been identified. We assessed the clinical and biological
factors predictive of bleeding control within the first 2 weeks after a bleeding
episode in a homogeneous group of patients enrolled in a large multicenter trial,
who underwent a standardized emergency sclerotherapy session. METHODS: 101
patients with cirrhosis were enrolled. All had endoscopy-proven variceal
bleeding, and the interval between hematemesis or melena and emergency
sclerotherapy was always less than 24 hours. A second sclerotherapy session and
other methods for the prevention of rebleeding were allowed after 5 days.
RESULTS: Treatment failed in 16 patients after 24 hours and in a total of 33
patients after 15 days. Three of the 17 variables included in multivariate
logistic analysis were associated with failure at 24 hours: encephalopathy (P =
0.006, OR = 4.0), blood transfusion prior to sclerotherapy (P = 0.012, OR = 6.2)
and previous propranolol therapy (P = 0.022, OR = 4.6). Two variables were
associated with failure between 24 hours and day 15 in patients successfully
controlled after 24 hours: an interval between the onset of bleeding and
sclerotherapy of less than 12 hours (P = 0.010) and blood transfusion (P =
0.018). After 15 days, three variables were associated with failure in a
multivariate Cox model: encephalopathy (P = 0.0025, OR = 2.3), time to
sclerotherapy (P = 0.022, OR 2.3) and blood transfusion before sclerotherapy (P =
0.0005, OR = 4.0). CONCLUSION: Encephalopathy, the severity of bleeding, assessed
in terms of transfusion requirements, and the time between clinically overt
bleeding and sclerotherapy are the main predictive factors of failure of the
control of bleeding after emergency sclerotherapy for acute bleeding from
esophageal varices.
PMID- 9762291
TI - [Autoimmune hepatitis induced by fibrates].
AB - AIM: Long term treatment by fibrates could induce chronic hepatitis associated
with auto-antibodies. The aim of this study was to assess the features of this
hepatitis. METHODS: Baseline clinical and biological features, and liver biopsy
in 5 patients with fibrate-induced chronic hepatitis were studied, as well as
their outcome. RESULTS: At enrollment, patients (4 men, mean age 65 years) had
highly (n = 3) or mildly (n = 2) increased serum aminotransferase activity,
hypergammaglobulinemia and high titers of anti-nuclear antibodies (with
homogenous fluorescence in 3 cases). Liver biopsies demonstrated a lympho
plasmocytic infiltrate in all cases. Hepatocellular necrosis was multilobular in
2 cases, and mild to moderate, located in lobular and periportal areas in 3
cases. Cirrhosis was found at presentation in 3 cases and developed within a few
months in the 2 other patients. After discontinuation of fibrates,
aminotransferase activity normalized within 6 weeks either spontaneously (n = 3)
or under immunosuppressive treatment (n = 2). Immunosuppression was rapidly
withdrawn in 2 patients (< 18 months) without relapse, while one patient was
treated for 4 years because of relapse after early withdrawal. A second liver
biopsy performed 6 months after discontinuation of fibrates in an untreated
patient showed no inflammation or necrosis. CONCLUSION: These observations
suggest that fibrates could trigger chronic liver disease resembling type I auto
immune chronic hepatitis, which resolves after drug withdrawal.
PMID- 9762292
TI - [Polarity of epithelial cells of the liver. Cellular and molecular mechanisms,
and pathologic changes].
PMID- 9762293
TI - [Myotomy for esophageal muscular hypertrophy with eosinophil infiltration of the
esophagus associated with toxocariasis revealed by esophageal motor disorder].
AB - We report the case of a 61-year-old-man with an eosinophilic esophagitis with
esophageal motor disorder associated with toxocariasis. He complained of non
cardiac chest pain and had eosinophilia leading to the detection of Toxocara
canis infection. Pain persisted despite treatment of toxocariasis. Basal
manometry was normal but ambulatory 24-hour manometry-pHmetry showed diffuse
esophageal spasm. Ultrasonography showed a thickening of the esophageal
musculature in the two inferior thirds of the esophagus. After failure of
treatment with sodium cromoglycate steroids and esophageal dilatation, calcium
antagonists were partially effective. A long esophageal myotomy was performed
permiting the disappearance of symptoms. The histological examination of a side
myotomy biopsy showed an eosinophilic infiltration of the esophageal muscle
layer. This observation leads to discuss the possible relation between
toxocariasis, the esophageal motor disorder and the eosinophilic infiltration of
the esophageal muscle layer.
PMID- 9762294
TI - [Dysphagia revealing Crohn's disease].
AB - Esophageal involvement in Crohn's disease is uncommon. We report here a case with
pre-eminent esophageal symptoms and numerous tuberculoid granulomas at
histopathological examination. This is an opportunity to review the differential
diagnoses and to describe the clinical, endoscopic and histopathological features
of this localisation.
PMID- 9762295
TI - [Macroaspartate aminotransferase. Study of 5 cases and review of the literature].
AB - Aspartate aminotransferase can exist as a macroenzyme, which has a higher
molecular mass than the corresponding enzyme normally found in serum under
physiologic or pathological conditions. This macroenzyme is often an
immunoglobulin complexed-enzyme and induces persistently increased serum
aspartate aminotransferase activity without any corresponding liver or muscle
damage. We report 5 patients with isolated and persistent increased serum
aspartate aminotransferase activity in whom a macroenzyme has been detected. Of
these 5 cases, four were apparently healthy subjects and the last had chronic
active hepatitis. Electrophoresis of aspartate aminotransferase isoenzymes of the
subjects' serum showed an abnormal band migrating between mitochondrial and
cytosolic aspartate aminotransferase. In 3 cases, the macrocomplex consisted of
aspartate aminotransferase and immunoglobulin G, as shown by the
immunoprecipitation method. In the patient with chronic active hepatitis, the
macroenzyme disappeared after liver transplantation. As macroaspartate
aminotransferase and others macroenzymes, may persist for months or even years,
it is important for clinicians to be aware of their existence to avoid
unnecessary invasive or costly procedures.
PMID- 9762296
TI - [Role of intravenous erythromycin in the preparation for endoscopy in case of
upper digestive hemorrhage].
PMID- 9762298
TI - [Endoscopic treatment of refractory hemorrhagic and ulcerated radiation proctitis
by a new electrocoagulation technique].
PMID- 9762297
TI - [Minocycline involvement in two cases of acute pancreatitis].
PMID- 9762299
TI - [Biliary ileus preceded by hematemesis: role of the tomodensitometry assessment].
PMID- 9762301
TI - [Alcoholism recurrence after liver transplantation for alcoholic cirrhosis].
PMID- 9762300
TI - [Bone marrow aplasia complicating viral hepatitis A with significant cholestasis:
a case report].
PMID- 9762302
TI - [Predictive value of clinico-biological factors in the diagnosis of lithiasis of
the common bile duct].
PMID- 9762303
TI - [Lithiasis of the common bile duct: ultrasonography, computed tomography, and
magnetic resonance cholangiography. Indications and results].
PMID- 9762304
TI - [Lithiasis of the common bile duct: endoscopic ultrasonography. Results and
indications].
PMID- 9762305
TI - [Endoscopic treatment of lithiasis of the common bile duct. Results and
indications].
PMID- 9762306
TI - [Surgical treatment of lithiasis of the common bile duct].
PMID- 9762307
TI - [Cost-effectiveness of various diagnostic and therapeutic approaches to lithiasis
of the common bile duct].
PMID- 9762308
TI - [Assessment of the quality of care and its development in France].
PMID- 9762309
TI - [Evidence-based medicine. Methodology for the development of medical and
professional recommendations. Research Group on the Digestive System (GRAD)].
PMID- 9762310
TI - [Which precautions should be taken in case of hepatitis C? From the statement of
the question to the dissemination of the response in a consensus conference].
PMID- 9762311
TI - [Evaluation of professional practices with the medical audit method].
PMID- 9762312
TI - [Conditions of development of the DBS/DH circular dated April 2, 1996 concerning
endoscope disinfection procedures in health care sites].
PMID- 9762313
TI - [Problems encountered with the application of the DGS/DH circular dated April 2,
1996 (concerning endoscope disinfection procedures) in hepato-gastroenterology
practice].
PMID- 9762314
TI - [Introduction to digestive tract pain].
PMID- 9762315
TI - [Pharmacologic approach to chronic pain. Recent findings].
PMID- 9762316
TI - [Management of pain in endoscopy: are there "gentle" alternatives to
anesthesia?].
PMID- 9762317
TI - [Management of chronic severe digestive tract pain].
PMID- 9762318
TI - [Visceral sensitivity and digestive functional disorders. Clinical significance
and therapeutic perspectives].
PMID- 9762319
TI - [Abdominal pain of metabolic and systemic origin].
PMID- 9762320
TI - [Surgical treatment of anal incontinence].
PMID- 9762321
TI - [Therapeutic approaches to rectal prolapse].
PMID- 9762322
TI - [Treatment of anal fistula].
PMID- 9762323
TI - [Anal fissure: new physiopathologic and therapeutic concepts].
PMID- 9762324
TI - [Hemorrhoid disease].
PMID- 9762325
TI - [Perineal neurologic pain].
PMID- 9762326
TI - [Liver transplantation in France. Current and future status, seen by the French
Establishment of Grafts].
PMID- 9762327
TI - [Influence of apolipoprotein E polymorphism in alcoholic cirrhosis].
AB - OBJECTIVE: To assess whether the polymorphism of apolipo-protein E was associated
with the development of alcoholic cirrhosis and could influence the severity of
liver injury evaluated by the Child-Pugh score. METHOD: We investigated 75
alcoholic patients with a histological diagnosis of cirrhosis, with negative HBV,
HCV serology and a control group of 54 subjects. Polymorphism of apolipoprotein E
was performed using PCR. RESULTS: There was no difference for the allele
frequency and the genotype in the cirrhotic group and the control group.
Cirrhotic patients with allele epsilon 2 had higher concentration of albumin (P =
0.01) and a higher level of apolipoprotein AII (P < 0.05) than those with allele
epsilon 3. They also had a higher concentration of apolipoprotein AI than
cirrhotic patients with allele epsilon 3 and epsilon 4 (P = 0.01). There was a
statistical difference between the three genotype groups for prothrombin time (P
= 0.01). There was no statistical difference between the three genotype groups
for Child-Pugh score. CONCLUSIONS: Polymorphism of apolipoprotein E was not
associated with the development of alcoholic cirrhosis. However patients with
allele epsilon 2 had better hepatocellular function.
PMID- 9762328
TI - [Helical CT of the liver. Principles and applications].
PMID- 9762329
TI - [Homogeneous groups of patients in Crohn's disease: reality or imagination?].
PMID- 9762330
TI - [Colonic involvement in ileal Crohn's disease].
AB - OBJECTIVES: To determine the risk and predictive factors for colonic extension in
patients with ileal Crohn's disease. METHODS: One hundred and fifty patients with
ileal Crohn's disease and no specific colonic lesions on initial colonoscopy were
studied retrospectively (median follow-up: 51 months). RESULTS: Twelve patients
(8%) developed colonic lesions. Ten-year cumulated risks (95% confidence
interval) for colonic extension were 17.2% (range: 5.8-28.6) in the whole group,
and 22.4% (range: 8.7-36.1) in the group of 86 patients with repeated
colonoscopy. Young age at diagnosis was the only factor predicting colonic
extension. Seven patients with colonic extension required immunosuppressive
therapy but none underwent surgery. CONCLUSION: Ileal Crohn's disease has a low
tendency for colonic extension. Colonic extension has no major prognostic
implications.
PMID- 9762331
TI - [Comparison of long-term course of perforating and non-perforating Crohn
disease].
AB - OBJECTIVES: To evaluate the influence of the indication of the first surgical
procedure on the prognosis of Crohn's disease. METHODS: We compared
retrospectively the long-term course of 179 patients operated on for a
perforating disease and 322 patients operated on for a nonperforating disease.
Mean follow-up was 11 years and 2 months in the two groups. RESULTS: Forty of 179
(25%) and 106 of 322 (33%) patients with perforating and nonperforating diseases
underwent a second intestinal resection, respectively. The patients who had been
operated on for a perforating disease were significantly more often reoperated on
for the same indication, and conversely. Patients with perforating diseases
experienced less second resections (actuarial rates: 37 +/- 11% vs 51 +/- 8% at
ten years respectively), less post-surgical handicaps (mean index 24.9 vs 27.9),
and fewer patients required immunosuppressive drugs (25 vs 35%). CONCLUSION: Long
term prognosis of perforating Crohn's disease does not appear to be more severe
than that of nonperforating disease.
PMID- 9762332
TI - [Gastrin-17 and G17-gly induce proliferation of LoVo cells through the CCK
B/gastrin receptor].
AB - BACKGROUND AND METHODS: Recent studies suggest that glycine-extended gastrin (G17
gly) stimulates in vitro proliferation of the pancreatic cell line AR4-2J,
through selective receptors distinct from the CCK-B/G-receptor mediating the
effects of amidated gastrin (G17). The aims of our study were to examine the
effects of G17 and G17-gly on the growth of the colorectal cancer cell line LoVo
and to determine the receptor involved by using selective receptor-antagonist.
RESULTS: Both G17 and G17-gly stimulated [3H]-thymidine incorporation in a
concentration-dependent fashion. Maximal stimulation (153 +/- 18% and 166 +/- 17%
of control, p < 0.01) was achieved with 10 nM G17 and 100 nM G17-gly,
respectively. These stimulations were fully prevented by the presence of 10 pM
YM022, a G/CCK B receptor-antagonist, but unaffected by L364,718, a CCK A
receptor-antagonist. Basal growth of LoVo cells was inhibited by YM022 and
stimulated by L364,718. CCK A and G/CCK B receptors mRNA were detected in the
cells. Gastrin immunoreactivity was detected in the cells (16 pM) and in the
extracellular medium (4.5 pM). CONCLUSION: Both G17 and G17-gly stimulate LoVo
cells growth through the activation of a gastrin/CCK B receptor. The evidence for
secreted gastrin and CCK A and B receptors mRNA may further suggest the existence
of an autocrine loop involving a stimulatory gastrin/CCK B receptor.
PMID- 9762333
TI - [Physiology and dysfunction of the upper esophageal sphincter].
PMID- 9762334
TI - [Central nervous system involvement in hepatitis C virus infection].
AB - Few well-documented cases of central nervous system involvement in patients with
hepatitis C virus infection have been reported. We describe three patients (two
men and one woman) with cerebral involvement (ischemia and/or hemorrhage).
Hepatitis C virus infection was confirmed in all patients by polymerase chain
reaction detection of hepatitis C virus RNA. These three cases document the
occurrence of central nervous system involvement in patients with hepatitis C
virus infection and mixed cryoglobulinemia. Cerebral involvement may be the
initial manifestation of hepatitis C virus infection.
PMID- 9762335
TI - [Epiphysis-metaphysis bone ischemia in hemorrhagic rectocolitis and Crohn's
disease].
AB - Aseptic osteonecrosis is a rare extraintestinal manifestation in patients with
inflammatory bowel disease; its true prevalence is not precisely known. Steroid
treatment undoubtedly participates in the pathophysiology of avascular
osteonecrosis, however, other factors like hypercoagulability may be involved.
Two cases of bilateral osteonecrosis of the knees--the first occurring during the
course of ulcerative colitis, the second in a patient presenting with Crohn's
disease--are described. Specific location of the lesions and regression of
symptoms, as well as the importance of magnetic resonance imaging for early
recognition of osteonecrosis, are noteworthy.
PMID- 9762336
TI - [Reversible nephrotic syndrome in Crohn's disease complicated with renal
amyloidosis].
AB - A 24-year-old woman suffered from ano-rectal Crohn's disease and nephrotic
syndrome due to glomerular amyloidosis AA. She received azathioprine and
colchicine for two years. Both Crohn's disease and nephrotic syndrome resolved.
However amyloid renal lesions were still present. This course is exceptional, and
leads to a discussion of the treatment of amyloidosis associated with Crohn's
disease.
PMID- 9762337
TI - [Ileocolic linitis in Crohn's disease].
AB - Intestinal cancer is uncommon in Crohn's disease but the risk of developing such
a tumor is increased. Linitis plastica of the small bowel or colon is very rare.
We report a case of ileocolonic linitis plastica which occurred 21 years after an
ileocecal resection for Crohn's disease. Partial small bowel obstruction in
relation with stricture of the preanastomotic loop prompted us to suspect disease
recurrence. The tumor was not diagnosed either on preoperative work-up, or during
surgery but only on the histological examination of the resected specimen.
Palliative chemotherapy with 5 FU and folinic acid was performed. The patient was
asymptomatic after a 17-month follow-up. This observation focuses on the clinical
signs and course of linitis plastica. It also illustrates the difficulty of tumor
diagnosis in Crohn's disease. Malignant transformation must be suspected if signs
of active disease re-occur after a lengthy quiescent period.
PMID- 9762338
TI - [Risk factors of hepatitis C virus contamination among patients admitted at the
Emergency Service of the Picardie Hospitals. Role of screening carried out
according to the recommendations of the General Direction of Health].
PMID- 9762339
TI - [Hepato-biliary involvement in lambliasis].
PMID- 9762340
TI - [Esophageal tubular duplication in the adult].
PMID- 9762341
TI - [Duodenal diaphragm-like stenosis caused by the long-term use of aspirin].
PMID- 9762342
TI - [A new treatment for hemorrhagic complications associated with severe liver
disease?].
PMID- 9762343
TI - Multifactorial mechanisms of drug resistance in tumor cell populations selected
for resistance to specific chemotherapeutic agents.
PMID- 9762345
TI - Characterization of PKC isozyme specific functions in cellular signaling.
PMID- 9762344
TI - Cancer cell heparanase activity associated with invasion and metastasis.
PMID- 9762347
TI - The role of multiple enzyme activation in metabolic flux control.
PMID- 9762346
TI - Novel advances in the regulation of signal transduction activity.
PMID- 9762348
TI - Regulation of mitogen-activated protein kinase cascades in the heart.
AB - Using primary cultures of neonatal rat ventricular myocytes and isolated adult
rat hearts as models, we have characterized extensively the regulation of MAPKs
in the heart. The ERKs are activated primarily by GPCR agonists acting through
PKC. These agonists can also activate the JNKs although the mechanism is unclear.
Cellular stresses stimulate strong activation of the JNKs, but also cause some
stimulation of ERKs. Activation of p38-MAPK has so far only been demonstrated in
intact adult hearts subjected to stresses and probably leads to activation of
MAPKAPK2. Both cellular stresses and GPCR agonists induce phosphorylation of c
Jun, but only the latter causes upregulation of c-Jun protein.
PMID- 9762349
TI - Regulation of secretory type-II phospholipase A2 and of lysophosphatidic acid
synthesis.
AB - Secretory non-pancreatic phospholipase A2 (sPLA2), also called type II-PLA2, is
produced in large amounts under inflammatory conditions, thus accumulating in
inflammatory fluids. Since the enzyme is virtually inactive on phospholipids from
intact cells, we have searched for conditions allowing the action of sPLA2 on
membrane phospholipids. Based on an in vitro model, our studies suggest that only
those membranes where the transverse distribution of phospholipids has been
disturbed offer a convenient surface able to interact with the enzyme, which then
achieves significant degradation of all glycerophospholipids. This results in the
accumulation of various lysophospholipids such as lysophosphatidylcholine,
lysophosphatidylethanolamine and lysophosphatidylserine. However,
lysophosphatidic acid (LPA) can also be generated under these conditions
involving accumulation of phosphatidic acid in the cytoplasmic leaflet of the
membrane, followed by its transfer to the outer monolayer. Since LPA is now
considered as a novel phospholipid mediator, this pathway deserves further
studies concerning mainly platelets, the main source of LPA identified so far.
PMID- 9762350
TI - Exploring the mechanistic aspects of mitomycin antibiotic bioactivation in
Chinese hamster ovary cells overexpressing NADPH:cytochrome C (P-450) reductase
and DT-diaphorase.
AB - We have directly demonstrated the involvement of human NADPH: cytochrome c (P
450) reductase in the aerobic/hypoxic differential toxicity of mitomycin C and
porfiromycin in living cells by varying only this enzyme in a transfected cell
line. In the same manner, we have implicated rat DT-diaphorase in the aerobic and
hypoxic activation of mitomycin C, but found only a minor role for this enzyme in
the aerobic activation of porfiromycin. DT-Diaphorase does not cause the
production of an aerobic/hypoxic differential toxicity by mitomycin C, but rather
activates this agent through an oxygen insensitive pathway. The evidence suggests
that DT-diaphorase activates mitomycin C more effectively than porfiromycin, with
porfiromycin being preferentially activated through a one-electron reductive
pathway. The therapeutic potential of mitomycin antibiotics in the treatment of
cancer can be envisioned to be enhanced for those tumors containing elevated
levels of the bioreductive enzymes. However, cytogenetic heterogeneity within the
tumor cell population and the various environmental factors which impact on
bioreductive enzyme function, including pH and oxygen tension, may subvert this
approach. Moreover, if high tumor levels of a drug activating enzyme reflect high
levels in the normal tissues of the patient, normal tissue damage may also be
enhanced with possibly no improvement in the therapeutic ratio. Approaches
utilizing gene therapy, whereby a specific bioreductive catalyst is introduced
into the tumor cell population via a targeting vehicle to activate a particular
prodrug, may be more effective in that not only will the prodrug of choice be
specifically activated in the tumor, but the source of the catalyst, be it
bacterial, rodent, or human, will not be important. In fact, in the case of DT
diaphorase and mitomycin C, the rat form of the enzyme could be advantageous
because it is more effective in activating mitomycin C than is the human form of
this enzyme. Assuming targeted gene delivery to malignant cells, a non-host
enzyme which is more effective at activating mitomycin C than the analogous host
enzyme might also result in less drug activation in normal tissue and, hence,
less normal tissue toxicity.
PMID- 9762352
TI - Post-genomic science: converting primary structure into physiological function.
PMID- 9762351
TI - Multiple folate enzyme inhibition: mechanism of a novel pyrrolopyrimidine-based
antifolate LY231514 (MTA).
AB - Extensive biochemical and pharmacological evidence indicates that LY231514 is a
novel antifolate antimetabolite. LY231514 is transported into cells mainly
through the reduced folate carrier system and extensively metabolized to
polyglutamated forms. The polyglutamates of LY231514 inhibit at least three key
folate enzymes: TS, DHFR, and GARFT, and to a lesser extent AICARFT and C1
tetrahydrofolate synthase. The combined effects of the inhibition exerted by
LY231514 at each target give rise to an unusual end-product reversal pattern at
the cellular level that is distinct from those of other inhibitors such as
methotrexate and the quinazoline antifolates. The metabolic effects exerted by
LY231514 on the folate and nucleotide pools are also quite distinct from those of
MTX and LY309887. The efficient polyglutamation, longer cellular retention and
the multiple folate enzyme inhibition mechanism may all have contributed directly
to the exciting antitumor responses now observed in Phase I and II studies. The
multitargeted inhibition mechanism of LY231514 is particularly intriguing. This
new level of mechanistic insight, which has evolved from the study of LY231514,
challenges the traditional concept and paradigm of antifolate drug discovery and
development which focused on developing very potent and selective inhibitors of
single folate enzyme targets, such as DHFR, TS or one of the enzymes along the de
novo purine biosynthetic pathway. Given the complex nature of folate metabolism
and the critical role of folates in maintaining the physiological functions of
living systems, it is completely reasonable to suspect that agents which can
interfere at multiple sites in the folate pathway may trigger and cause more
biochemical imbalance in the cellular DNA and RNA synthesis of malignant cells
than agents that act on a single point (Fig. 5). In conclusion, LY231514 (MTA) is
a new generation antifolate antimetabolite demonstrating inhibitory activity
against multiple folate enzymes including TS, DHFR and GARFT. In current phase II
studies, MTA is broadly active as a single agent and is showing very encouraging
antitumor activity in multiple solid tumors including colorectal, breast and non
small cell lung cancers (38-43). The every three week dosing schedule has proven
to be convenient and easy to administer and the clinical toxicities of LY231514
seem to be well tolerated. More advanced and extensive clinical trials of
LY231514 are currently in progress.
PMID- 9762353
TI - Towards the structure-based design of oligonucleotide therapeutics.
PMID- 9762354
TI - AH receptor-controlled transcriptional regulation and function of rat and human
UDP-glucuronosyltransferase isoforms.
AB - Transcriptional regulation and function of rat and human PAH-inducible UDP
glucuronosyltransferase (UGT) isoforms have been studied. 1. At least two PAH
inducible UGT isoforms are expressed in a variety of tissues, the rat isoforms
UGT1A6 and UGT1A7, and the human isoforms UGT1A6 and UGT1A9. 2. For the rat and
human UGT1A6 isoforms two modes of tissue- and cell-specific regulation were
found, PAH-inducible and constitutive expression. 3. Transient transfection
studies, using human UGT1A6/CAT fusion constructs and colon carcinoma Caco-2
cells, revealed that PAH induction of human UGT1A6 is mediated by the Ah
receptor. 4. Cell-expressed UGT isoforms were used to study their function in PAH
metabolism. Rat UGT1A7 and human UGT1A9 appear to be more efficient than the
corresponding UGT1A6 isoforms in catalyzing glucuronide formation of PAH phenols
and diphenols. Several isoforms may act together in the formation of
benzo(a)pyrene-3.6-diol diglucuronide, the major glucuronide found in rat bile.
The results suggest complex modes of transcriptional regulation of PAH-inducible
UGTs. They also suggest a major role of these UGT isoforms in detoxication of
PAHs.
PMID- 9762355
TI - Gene expression and regulation of N-acetylglucosaminyltransferases III and V in
cancer tissues.
PMID- 9762356
TI - Novel physiological functions of cathepsins B and L on antigen processing and
osteoclastic bone resorption.
AB - Lysosomal cathepsin B plays an essential role in the processing of ovalbumin as
an exogenous antigen to produce the complex between antigenic-peptide and major
histocompatibility-complex class II. Administration of cathepsin B inhibitors, E
64, CA-074 and vitamin B6, caused the strong suppression of the Th-2 type immune
responses. We found that pyridoxal phosphate (PAP), a coenzyme form of vitamin
B6, inhibits the activities of cathepsin B and L in vitro and vitamin B6
administration induces the inhibition of the lysosomal cathepsin activities in
vivo. The production of an antigenic epitope (I323-R339) of ovalbumin by antigen
presenting cells was suppressed by cathepsin B specific inhibitors. The ovalbumin
dependent production of immunoglobulins (IgE and IgG1) and of the corresponding
interleukin (IL-4) was suppressed by cathepsin B inhibitors, while the production
of IgG2a and interferon (INF-gamma) was increased. The switch of helper T
lymphocyte functions from the type-2 to the type-1 may be induced by the
cathepsin B inhibition. The experimental bone pit formation, i.e., osteoclastic
bone collagen degradation test, induced by parathyroid hormone was markedly
suppressed by the administration of pyridoxal, because of the inhibition of
cathepsin L type cysteine proteases in bone.
PMID- 9762357
TI - A role for the amino terminus of human topoisomerase I.
AB - These studies indicate that SV40T antigen binds the amino terminus of human top1
both in vitro and in vivo. Additional in vitro data suggest that the interaction
between these two proteins does not require DNA as an intermediary. Taken
together with the finding that the amino terminus of top 1 binds the putative
helicase nucleolin, these results implicate helicase binding as a general
function of the amino terminus of human top1. Binding of top1 by helicases may be
important in the management of structural alterations in DNA produced by
helicases. The potential importance of helicase-topoisomerase interactions has
been highlighted by recent data indicating that the protein defective in Bloom's
syndrome is a helicase with a yeast homologue that is known to bind
topoisomerases.
PMID- 9762358
TI - Regulation of apoptosis in Xenopus egg extracts.
PMID- 9762359
TI - Vasculature and microenvironmental gradients: the missing links in novel
approaches to cancer therapy?
AB - This paper illustrates how the concept of the malignant cell per se as the prime
and only target in cancer therapy may be erroneous. The micro-vasculature evoked
to satisfy nutritional requirements of solid tumors, and the inadequacy of this
nutrition for all tumor cells, provide novel targeting concepts. The vascular
architecture and the microenvironmental gradients (VAMP) will differ from one
tumor to another and may determine whether current therapies succeed or fail.
Many agents have a different toxicity or mode of action at the pathophysiological
oxygen tensions that prevail in solid tumors. This warrants more attention. The
hypoxic cell or the immature proliferating endothelial cell may provide tumor
specificity that is more general than, and greater than, that conferred by the
process of malignant transformation. The poor vasculature of solid tumors is
often regarded as a problem by the oncologist. It limits the access of cytotoxic
drugs, monoclonal antibodies, cytokines, etc. It also leads to hypoxic
radioresistance because of diffusion limited chronic hypoxia and perfusion
limited intermittent hypoxia, resulting from transient vessel closure. However,
it can also be seen as a potential target, since prolonged vessel occlusion can
lead to an avalanche of cell death. Strategies to prevent further expansion of
the vascular network (anti-angiogenesis) should stabilize tumors and prevent
further growth. Vascular targeting, aiming to damage the microvascular function
and cause occlusion, can lead to extensive cell death. The target may relate to
the excessive proliferation of endothelial cells in tumors or to abnormal
functional aspects, such as altered cell shape (influencing permeability)
adhesiveness to leukocytes or steps in the coagulation cascade. These
microvascular features and microenvironmental gradients, and the phenotypic
consequences of them, have been relatively neglected. The altered milieu and
inadequate neovasculature is a common feature of all types of solid tumor,
whereas the genetic changes that can give rise to a malignancy are very variable,
from tumor site to site and even within a site from individual to individual. It
seems, therefore, that therapies that could be of widespread general
applicability might more easily be found from the micro-environmental or anti
vascular approaches than from gene therapy targeted at specific oncogenes. This
approach will require cross fertilisation between scientists from quite disparate
backgrounds, whose paths seldom cross, and who may not read, or even scan, each
other's literature. If the endothelium or the low oxygen tension in subsets of
tumor cells are the key to successful cancer treatment in mice, there are
considerable implications for screening methods in vitro and for predictive and
prognostic tests made on homogenized tumor samples.
PMID- 9762360
TI - The physiological role of glucokinase binding and translocation in hepatocytes.
AB - The compartmentation of glucokinase in the hepatocyte is regulated by the
extracellular glucose concentration and by substrates that alter the
concentration of fructose 1-phosphate in the hepatocyte. At low glucose
concentrations, that mimic the fasted state, glucokinase is sequestered in an
inactive state bound to the 68 kDa regulatory protein in the nucleus. In these
conditions the rate of glucose phosphorylation is less than 15% of the total
glucokinase activity. An increase in extracellular glucose concentration, within
the range occurring in the portal vein in the absorptive state, or low
concentrations of fructose or sorbitol (precursors of fructose 1-phosphate),
cause the translocation of glucokinase from the nucleus to the cytoplasm and this
is associated with a corresponding increase in glucose phosphorylation. The
effect of glucose on translocation is mimicked by mannose which is also
phosphorylated by glucokinase as well as by competitive inhibitors of glucokinase
(mannoheptulose and 5-thioglucose) which are not phosphorylated. Various lines of
evidence suggest that the action of these analogues is most likely due to binding
to an allosteric or non-catalytic site. The saturation curve of glucose
phosphorylation in intact hepatocytes is sigmoidal with an S0.5 of approximately
20 mM and a Hill coefficient approximately 2. This saturation curve can be
explained by the activity of glucokinase in the cytoplasmic compartment.
Translocation of glucokinase from the nucleus to the cytoplasm in response to
precursors of fructose 1-phosphate (which cause dissociation of glucokinase from
the regulatory protein) is associated with stimulation of glucose
phosphorylation, glycolysis and glycogen synthesis. Using Metabolic Control
Analysis to determine the Control Coefficient (Control Strength) of cytoplasmic
(free) glucokinase on glucose metabolism it can be shown that the free
glucokinase activity has a very high control strength on glycogen synthesis
(CFGKJ > 1), indicating a major role of translocation of glucokinase in the
control of hepatic glycogen synthesis. Overexpression of glucokinase in
hepatocytes by adenovirus-mediated glucokinase overexpression is associated with
a marked increase in glycogen synthesis. The relation between glycogen synthesis
and enzyme overexpression is sigmoidal with an enzyme concentration causing half
saturation (S0.5) in the physiological range. The high Control Coefficient of
glucokinase on hepatic glycogen synthesis explains the abnormalities of hepatic
glycogen synthesis in patients with a single mutant allele of the glucokinase
gene (Maturity Onset Diabetes of the Young, type 2).
PMID- 9762361
TI - Tumor necrosis factor-alpha mediated activation of signal transduction cascades
and transcription factors in 3T3-L1 adipocytes.
AB - We have previously demonstrated that exposure of fully differentiated 3T3-L1
adipocytes to TNF results in an activation of at least two separate signal
transduction pathways: 1. the sphingomyelinase leading to generation of ceramide
and 2. the proliferative and cell growth regulating p44/42 MAP kinase cascade. In
the current study we extend those observations and examine the ability of both
TNF and ceramide to activate the stress/cytokine activated p38 MAPK, the JNK and
JAK-STAT pathways. Interestingly, the p38 MAP kinase was observed to be
constitutively active and its phosphorylation status (activation) was not altered
with either TNF or ceramide treatment. Analysis of the JNK and JAK-STAT pathways
also demonstrated an absence of TNF-induced activation. Similar results were
obtained when the adipocytes were treated with a cell permeable analog of
ceramide. However, the adipocytes were observed to respond to TNF with a rapid
alteration in the GSH-GSSG equilibrium in a manner consistent with a cellular
response to an oxidative stress. This response may mediate the TNF-induced
metabolic disturbances observed in the adipose cell.
PMID- 9762362
TI - Inositides in the nucleus: taking stock of PLC beta 1.
AB - The nucleus was shown to be a site for inositol lipid cycle which can be affected
by treatment of quiescent cells with growth factors such as IGF-I. In fact, the
exposure of Swiss 3T3 cells to IGF-I results in a rapid and transient increase in
nuclear PLC beta 1 activity. In addition, several other reports have shown the
involvement of PLC beta 1 in nuclear signalling in different cell types. Indeed,
PLC beta 1 differs from the PLC gamma and della isozymes in that it has a long
COOH-terminal sequence which contains a cluster of lysine residues that are
critical for association with the nucleus. Although the demonstration of PtInsP
and PtdInsP2 hydrolysis by nuclear PLC beta 1 established the existence of
nuclear PLC signalling, the significance of this autonomous pathway in the
nucleus has yet to be thoroughly clarified. By inducing both the inhibition of
PLC beta 1 expression by antisense RNA and its overexpression we show that this
nuclear PLC is essential for the onset of DNA synthesis following IGF-I
stimulation of quiescent Swiss 3T3 cells. Moreover, using a different cell
system, i.e. Friend erythroleukemia cells induced to differentiate towards
erythrocytes, it has been evidenced that there is a relationship between the
expression and activity of nuclear PLC beta 1 and the association of PI-PT alpha
with the nucleus in that, when PLC activity ceases, in differentiated and resting
cells at the same time there is a dramatic decrease of the association of PI-PT
alpha with the nucleus.
PMID- 9762363
TI - Nuclear inositol signaling: a structural and functional approach.
PMID- 9762364
TI - Cobalamin-dependent methionine synthase and serine hydroxymethyltransferase:
targets for chemotherapeutic intervention?
AB - Chemotherapeutic drugs targeted at folate-dependent reactions have typically been
directed at a limited number of target enzymes: dihydrofolate reductase,
thymidylate synthase, and GAR and AICAR transformylase. This review discusses two
other potential targets for chemotherapeutic inhibition: cobalamin-dependent
methionine synthase and serine hydroxymethyltransferase. Brief reviews of the
catalytic properties of these two enzymes are presented, and possible strategies
for chemotherapeutic intervention are discussed.
PMID- 9762365
TI - Comparison of proliferating cell nuclear antigen expression in odontogenic
keratocyst and ameloblastoma: an immunohistochemical study.
AB - Proliferating cell nuclear antigen (PCNA) is a nuclear protein synthesized in the
late G1 and S phase of the cell cycle, and immunohistochemical detection of the
protein represents a useful marker for the proliferating fraction of cells in
tissue specimens. PCNA expression was studied in odontogenic keratocysts (n = 15)
and ameloblastomas (n = 46) using an avidin-biotin-peroxidase complex method on
routinely processed paraffin sections. The percentage of PCNA-positive cells
determined by point counting was significantly lower in the ameloblastomas (mean
9.4%, standard deviation (SD) 11.0) than in odontogenic keratocysts (mean 29.9%,
SD 24.0). In ameloblastomas, the mean percentage of PCNA-positive cells was
lowest in the acanthomatous pattern and highest in plexiform pattern. The mean
percentage of PCNA-positive cells in plexiform pattern was non-significantly
higher than that in follicular pattern. The mean percentage of PCNA-positive
cells in plexiform and follicular patterns was significantly higher than that in
cystic and acanthomatous patterns. The frequency of PCNA-positive cells was
significantly higher in the peripheral cells of follicular and plexiform patterns
than in the central cells of both patterns (p < 0.01). Therefore, peripheral
cells were regarded as reserve cell of central cells. The mean percentage of PCNA
positive cells in the epithelial lining of odontogenic keratocyst was not
significantly different from those in the peripheral cells of follicular and
plexiform patterns of ameloblastoma. In contrast, the odontogenic keratocyst
exhibited a mean percentage of PCNA-positive cells which was statistically higher
than that in other histological elements of ameloblastomas. The present study
suggests that odontogenic keratocyst is regarded as benign odontogenic tumour.
PMID- 9762366
TI - Nuclear and nucleolar image analysis of human breast epithelial cells transformed
by benzo[a]pyrene and transfected with the c-Ha-ras oncogene.
AB - Changes in nuclear and nucleolar morphometric parameters were investigated by
image analysis procedures in human breast MCF-10F epithelial cells expressing
different stages of the tumourigenic progression after benzo[a]pyrene (BP)
transformation (BP1, BP1-E, and BP1-E1 cell lines), and additionally transfected
with the c-Ha-ras oncogene (BP1-Tras cell line). Nuclear pleomorphism was evident
in all the transformed cells. The analysis of different morphometric parameters
did not show a clear relationship between specific nuclear and nucleolar changes
and the expression of the different stages of the tumourigenesis, with the
exception of the nucleolar size, which could be associated to the expression of
the tumourigenic phenotype, and a nucleolar area/nuclear area ratio, which
discriminated the immortalized, the transformed, and the tumourigenic phenotypes
from one another. The nuclear morphometric data established for the BP
transformed cells and for the cells additionally transfected with the c-Ha-ras
oncogene were suggestive of complex and distinct morphofunctional mechanisms
involving the in vitro transformation of the MCF-10F cells. The nuclear changes
found in the BP1-Tras cell line were assumed to be related to the additional
effects and/or enhanced genomic instability induced by transfection with the ras
oncogene.
PMID- 9762367
TI - Detection of c-erbB-2 mRNAs using dig-labelled oligonucleotide probe with in situ
hybridisation in human breast carcinoma: comparison with immunohistochemical
results.
AB - Amplification and overexpression of the c-erbB-2 oncogene are of prognostic
significance in human breast cancer. Overexpression of c-erbB-2 is the result of
gene amplification. However, increased transcript levels of c-erbB-2 are also
detected in the absence of gene amplification. In this study for the detection of
the overexpression mRNA in situ hybridisation (ISH) and immunohistochemistry
(IHC) were used. Our aim was to develop the suitable mRNA ISH protocol for
formalin-fixed paraffin-embedded material and to compare the localisation of
transcripts and protein products in 20 primary breast carcinomas. Sections were
immunostained with monoclonal c-erbB-2 antibody. In ISH method digoxigenin
labelled oligoprobe was used for the detection of c-erbB-2 mRNAs. We determined
optimal condition for the ISH procedure (e.g., probe concentration, digestion,
post washing). c-erbB-2 protein overproduction was detected in 11/20 cases with
IHC. The mRNA signals were observed in malignant cell cytoplasm in 6/20 cases by
ISH. ISH positive signals were found in only one case without detected
overexpression of the protein. There were cell to cell variations in the
hybridisation signals even within individual tumours. The ISH and IHC positive
signals for c-erbB-2 was observed mostly in infiltrating ductal carcinomas that
belong to aggressive lesions.
PMID- 9762368
TI - Fast-FISH detection and semi-automated image analysis of numerical chromosome
aberrations in hematological malignancies.
AB - A new fluorescence in situ hybridization (FISH) technique called Fast-FISH in
combination with semi-automated image analysis was applied to detect numerical
aberrations of chromosomes 8 and 12 in interphase nuclei of peripheral blood
lymphocytes and bone marrow cells from patients with acute myelogenous leukemia
(AML) and chronic lymphocytic leukemia (CLL). Commercially available alpha
satellite DNA probes specific for the centromere regions of chromosome 8 and
chromosome 12, respectively, were used. After application of the Fast-FISH
protocol, and microscopic images of the fluorescence-labelled cell nuclei were
recorded by the true color CCD camera Kappa CF 15 MC and evaluated quantitatively
by computer analysis on a PC. These results were compared to results obtained
from the same type of specimens using the same analysis system but with a
standard FISH protocol. In addition, automated spot counting after both FISH
techniques was compared to visual spot counting after standard FISH. A total
number of about 3,000 cell nuclei was evaluated. For quantitative brightness
parameters, a good correlation between standard FISH labelling and Fast-FISH was
found. Automated spot counting after Fast-FISH coincided within a few percent to
automated and visual spot counting after standard FISH. The examples shown
indicate the reliability and reproducibility of Fast-FISH and its potential for
automatized interphase cell diagnostics of numerical chromosome aberrations.
Since the Fast-FISH technique requires a hybridization time as low as 1/20 of
established standard FISH techniques, omitting most of the time consuming working
steps in the protocol, it may contribute considerably to clinical diagnostics.
This may especially be interesting in cases where an accurate result is required
within a few hours.
PMID- 9762369
TI - DNA aneuploidy by flow cytometry is an independent prognostic factor in gastric
cancer.
AB - In the present study the prognostic value of both DNA ploidy and the
proliferative activity of tumour cells were studied in a series of 76 consecutive
patients suffering from gastric tumours. DNA ploidy and the proliferative index
(as measured by the percentage of S-phase cells) were determined by flow
cytometry using fresh tumour specimens. The presence of DNA aneuploid clones by
flow cytometry was detected in 62% of the cases (mean DNA index of 1.63 +/- 0.46;
range 1.08-2.92), the mean proportion of S-phase cells being of 18.4 +/- 11.5%.
In comparison with diploid cases, aneuploid tumours showed a higher proliferative
activity (cases with more than 15% S-phase cells: 18.4% versus 6.1%, p = 0.0001)
as well as a higher incidence of node involvement (95% versus 68%, p = 0.001). By
contrast, no significant differences were detected with respect to sex, age,
histologic grade and type, clinical stage, tumour size and the incidence of
extranodal involvement. Upon grouping the patients according to the proportion of
S-phase cells no significant differences were observed for the clinical and
biological parameters explored except for an association between a high
percentage of S-phase cells and the presence of DNA aneuploidy (40% versus 96%, p
= 0.0001). Regarding survival the presence of DNA aneuploidy was significantly
associated with poor outcome as compared to the diploid cases (median of 15
versus 26 months, p = 0.005). By contrast, the proportion of S-phase cells did
not predict patients's outcome. Multivariate analysis of prognostic factors
showed that the presence of DNA aneuploidy (p = 0.003) together with the
histologic type (p = 0.03) and the existence of extranodal metastases (p = 0.05)
were the best combination of prognostic factors for survival prediction.
PMID- 9762370
TI - Cell proliferation activity and prognostic index in squamous cell lung carcinoma.
AB - Flow Cytometry (FC) has been incorporated into cancer research in relation to its
prognostic value together with histological parameters and TNM stages. We have
studied by means of FC the cell cycle of 132 samples from male patients with
Squamous Cell Lung Carcinoma (SQCLC). All of the patients received curative
surgery and the clinical follow-up was 60 months. The clinical and cytometric
parameters were evaluated in order to predict the patients' outcome. The presence
of tumoural recurrence and the tumoural stage showed statistical significance
associated with survival. The multivariant analysis reveals radiotherapy (p =
0.004) as protective variable and the high S-phase fraction (SPF) (p = 0.001) and
stage IIIA (p = 0.012) as risk factors. The SPF appears as an independent
prognostic factor for overall survival time. We can build a prognostic index
representative of different prognostic groups, which allows us to improve the
individual monitoring of these patients.
PMID- 9762371
TI - Stress ulcer prophylaxis in medical ICU patients: annual utilization in relation
to the incidence of endoscopically proven stress ulceration.
AB - OBJECTIVE: To measure changes in the proportion of medical intensive care unit
(MICU) patients prescribed pharmacologic stress ulcer prophylaxis therapy over a
4-year period in relation to the incidence of stress-related ulceration detected
by endoscopy at our institution. DESIGN: Retrospective 4-year review of pharmacy
and endoscopy databases. SETTING: A 35-bed MICU. PATIENTS: Patients (n = 2941)
admitted to the MICU for longer than 24 hours, between January 1, 1993, and
December 31, 1996, without acute gastrointestinal hemorrhage on admission.
METHODS: Records were reviewed to identify patients prescribed pharmacologic
stress ulcer prophylaxis (> 24 h of sucralfate or a histamine2-receptor
antagonist [H2RA]), and patients with evidence of stress ulceration during
endoscopy. RESULTS: The number of patients per year receiving stress ulcer
prophylaxis significantly (p < 0.001) decreased between 1993 and 1996: 1993,
492/693 (71%); 1994, 478/798 (60%); 1995, 295/670 (44%); 1996, 164/780 (21%).
There was no difference between years in the median duration of stress ulcer
prophylaxis therapy or the proportion of patients receiving sucralfate versus
H2RA therapy. There was no difference (p = 0.91) between years in the annual
incidence of definite or possible stress-related ulceration: 1993, 6/693 (0.87%);
1994, 5/798 (0.63%); 1995, 6/670 (0.90%); 1996, 5/780 (0.64%). CONCLUSIONS: The
incidence of endoscopically proven stress-related ulceration has remained
unchanged over the past 4 years in our MICU despite significantly fewer patients
receiving pharmacologic stress ulcer prophylaxis therapy.
PMID- 9762372
TI - Effect of a dual-lumen peripheral catheter on the delivery of known incompatible
medications.
AB - OBJECTIVE: To determine the degree to which a dual-lumen peripheral catheter
prevented precipitation of solutions known to be incompatible due to pH during
simultaneous infusion in an in vitro model. METHODS: An in vitro model was
devised to simulate peripheral venous blood flow from an antecubital source to
systemic circulation. Ondansetron was simultaneously infused with fluorouracil,
aminophylline, sodium bicarbonate, and ampicillin sodium in concentrations
reflective of clinical conditions into the Twin Cath 20/22 (the dual-lumen
catheter used in this experiment). Study solutions were primed with the prepared
drug solution and administered for 15 minutes. Phase I used Normosol-R as the
diluent to gather preliminary data; phase II used human plasma. All samples were
obtained immediately before the start of the infusion and at 5, 10, and 15
minutes during the infusion, and 5 minutes after the infusion. Samples were
visually inspected at each time point for precipitation and analyzed in duplicate
by the appropriate stability-indicating HPLC method (except for sodium
bicarbonate). Compatibility was defined as no visual evidence of precipitation
and no more than 15% mean change in final versus initial concentration. RESULTS:
Phase I experiments showed immediate precipitation in Normosol-R within the
venous flow. However, in phase II, because of the buffering capacity that plasma
proteins add to plasma, no precipitation occurred. All the drug combinations used
in this study have been reported to be incompatible at the concentrations tested;
however, we detected no incompatibilities. CONCLUSIONS: The results of this study
indicate that using a dual-lumen peripheral catheter, such as the Twin Cath, may
allow solutions incompatible due to pH to be administered simultaneously.
PMID- 9762373
TI - Pharmacoeconomic analysis of using Sinemet CR over standard Sinemet in
parkinsonian patients with motor fluctuations.
AB - OBJECTIVE: To compare the costs of pharmacotherapy in patients with Parkinson's
disease before and after converting from standard Sinemet to extended-release
Sinemet CR. DESIGN: Investigators retrospectively reviewed records of patients
converting from Sinemet to Sinemet CR for efficacy and total drug costs. Cost
effectiveness was evaluated retrospectively from data collected in prospective
Sinemet CR efficacy trials. SETTING: Parkinson's disease clinic at a tertiary
care university teaching hospital. PATIENTS: 100 patients with motor fluctuations
who had undergone an initial 6-month course of Sinemet therapy, followed by a 6
month course of Sinemet CR. MAIN OUTCOME MEASURES: Total cost was measured as the
cost of Sinemet formulations plus the costs of other antiparkinson medications.
Differences in pre- and postconversion costs were compared by using the paired,
two-tailed Student's t-test. A substudy of 39 patients on the cost-effectiveness
of conversion measured the ratio of daily medication costs to the daily hours
"on" without chorea. RESULTS: While total daily medication costs after conversion
increased by 21%, patients experienced either a comparable or an improved degree
of disease control with Sinemet CR. Patients who were also taking selegiline were
able to decrease selegiline expense by 20%. The costs of other adjunctive
medications did not differ significantly after conversion. The cost-effectiveness
analysis revealed an increase in postconversion on time by 2.2 hours (p =
0.0001), accompanied by a $2.85 decrease in total cost per hour on without chorea
(p = 0.11). CONCLUSIONS: Although Sinemet CR is more costly, it may be more cost
effective in patients with motor fluctuations. Some patients may be able to
reduce adjunctive medications.
PMID- 9762374
TI - Concomitant rash and blood dyscrasias in geriatric psychiatry patients treated
with carbamazepine.
AB - BACKGROUND: Rashes and blood dyscrasias are disconcerting adverse effects
associated with carbamazepine therapy. Rashes are quite common, as are mild blood
dyscrasias, such as mild leukopenias. Fortunately, severe rashes and blood
dyscrasias are rare. There are few reports on the relationship between
carbamazepine-induced rashes and blood dyscrasias, including a prospective study
in which rash appeared concomitantly with leukopenia and/or thrombocytopenia in
10 patients, two case reports in which simultaneous rash and agranulocytosis
occurred, and two case reports in which rashes served as harbingers of fatal
aplastic anemia. CASE REPORTS: We report two cases of concomitant rashes and
blood dyscrasias in geriatric psychiatry patients receiving carbamazepine therapy
for bipolar disorder. One patient was found to have a severe leukopenia within
several days after rash onset. The other patient was discovered to have a severe
leukopenia and thrombocytopenia within about a month after rash onset.
DISCUSSION: Current hematologic monitoring guidelines for carbamazepine rely
heavily on the recognition of signs and symptoms of blood dyscrasias by
clinicians and patients. We believe that our cases support the suggestion that
patients who develop rashes receive more vigilant monitoring of the complete
blood count, should carbamazepine therapy by continued. Given the currently
available case reports and the fact that the incidence of drug-induced blood
dyscrasias increases with advanced age, this recommendation may be particularly
relevant for geriatric patients. CONCLUSIONS: Further study is required to
establish whether carbamazepine-induced concomitant rashes and blood dyscrasias
are valid associations insofar as monitoring is concerned.
PMID- 9762375
TI - Minocycline-associated tooth staining.
AB - OBJECTIVE: To describe a case of tooth discoloration in an adult after
minocycline treatment for arthritis. CASE SUMMARY: A 68-year-old white women
presented with blue-black staining of her lower anterior teeth after 4 months of
minocycline therapy for arthritis. Her other medications are not known to cause
discoloration of teeth. While the patient continued taking minocycline, her
dentist was not able to remove the discoloration. Within 1 month after
discontinuation of the minocycline, the dentist was able to remove the
discoloration entirely. DISCUSSION: Minocycline, a synthetic derivative of
tetracycline, has been shown to cause abnormal pigmentation of the skin, thyroid
gland, nails, bone, sclera, and conjunctiva in adults. It also has been shown to
cause tooth discoloration in a few patients. This case is unusual in that the
tooth discoloration disappeared after discontinuing minocycline therapy.
CONCLUSIONS: This complication of minocycline is more commonly thought of in the
pediatric population. However, clinicians need to be aware of this adverse drug
reaction, as this agent may be used increasingly in the treatment of adults with
arthritis.
PMID- 9762376
TI - Isoniazid-induced psychosis.
AB - OBJECTIVE: To report a suspected case of isoniazid-induced psychosis in a 31-year
old woman. CASE SUMMARY: A 31-year-old white woman without a prior psychiatric
history presented with psychotic symptoms suspected to be related to prophylactic
treatment with isoniazid after she tested positive to a tuberculin (purified
protein derivative) test. The psychotic symptoms resolved partially after
isoniazid was discontinued and completely after treatment with olanzapine was
begun. The patient remained symptom-free 11 months after discharge from the
hospital. DISCUSSION: Cases of isoniazid-related psychiatric disorders reported
in the literature include psychosis, obsessive-compulsive neurosis, and mania.
With the increasing prevalence of tuberculosis in the US, more people are
expected to receive treatment for tuberculosis. Pyridoxine deficiency may play a
role in the pathogenesis of isoniazid-induced psychosis. Such deficiency states
may be detected indirectly by measuring urinary metabolites of tryptophan.
CONCLUSIONS: Clinicians should be aware of this adverse effect of isoniazid and
that it may present with a broad clinical picture.
PMID- 9762378
TI - Issues surrounding tight glycemic control in people with type 2 diabetes
mellitus.
AB - OBJECTIVE: To review the prospective evidence surrounding the issue of tight
glycemic control in people with type 2 diabetes mellitus and resultant long-term
complications. DATA SOURCE: Conference proceedings and a MEDLINE search (1966
February 1998) identified pertinent English-language publications on type 2
diabetes in humans. Key search terms included insulin resistance, diabetes
mellitus, non-insulin-dependent, macrovascular complications, microvascular
complications, and intensive glycemic control. STUDY SELECTION: Selection of
prospective epidemiologic and clinical studies were limited to those focusing on
the management of type 2 diabetes. All articles with pertinent information
relevant to the scope of this article were reviewed. DATA SYNTHESIS: The
pathophysiology of type 1 and type 2 diabetes differ; however, both share chronic
complications that significantly affect morbidity and mortality. People with type
1 diabetes have an absolute deficiency of insulin, whereas people with type 2
diabetes have varying degrees of insulin resistance and an inadequate
compensatory insulin secretory response. The Diabetes Control and Complications
Trial (DCCT) has clearly indicated that intense control of blood glucose in type
1 diabetes prevents and slows the progression of microvascular (i.e.,
retinopathy, nephropathy) and neuropathic complications. The Kumamoto study
showed similar results in nonobese patients with type 2 diabetes. Intense insulin
therapy in both populations has proven advantageous, thus supporting a common
pathophysiologic process for the microvascular and neuropathic complications.
Trends were seen toward fewer macrovascular (atherosclerotic disease)
complications in the intensive insulin arm of the DCCT. Conversely, trends were
seen toward an increase in macrovascular complications in the VA Cooperative
study in people with type 2 diabetes using intensive insulin therapy. This may
suggest a discordance in the pathophysiology of macrovascular disease between
type 1 and type 2 diabetes. Additionally, it remains uncertain whether tight
glycemic control prevents the onset or slows the progression of macrovascular
disease. Two studies (the University Group Diabetes Program and the Veterans
Affairs Cooperative Study on Glycemic Control and Complications in Type 2
Diabetes) to date have examined pharmacotherapy options for patients with type 2
diabetes and resultant macrovascular complications. It has yet to be determined
whether any therapeutic intervention will decrease the morbidity and mortality of
macrovascular disease in this population. CONCLUSIONS: In type 2 diabetes,
limited prospective evidence does support tight glycemic control to help prevent
or slow the progression of microvascular and neuropathic complications. It is
uncertain whether tight glycemic control decreases macrovascular complications
and which pharmacotherapeutic agent(s) is/are the best options. However, therapy
that improves glucose control in combination with aggressive risk factor
management should be initiated and enforced in patients with type 2 diabetes in
an effort to reduce long-term complications.
PMID- 9762377
TI - Rhabdomyolysis after correction of hyponatremia due to psychogenic polydipsia
possibly complicated by clozapine.
AB - OBJECTIVE: To report a case of rhabdomyolysis related to rapid correction of
hyponatremia attributable to compulsive drinking of water, possible complicated
by clozapine use. CASE SUMMARY: A 42-year-old white man treated with clozapine
for schizophrenia was admitted for a generalized seizure. Marked hyponatremia due
to psychogenic polydipsia was present. He developed a marked elevation of
creatine kinase concentrations after correction of hyponatremia with hyperosmolar
sodium solution, without clinical signs of rhabdomyolysis. DISCUSSION:
Rhabdomyolysis associated with hyponatremia due to water intoxication has been
reported in 17 patients to date. A possible explanation may lie within the
framework of the calcium-sodium exchange across the skeletal muscle cell
membrane. By increasing muscle cell permeability, clozapine treatment may
possibly enhance the destruction of muscle cells. CONCLUSIONS: Hyponatremia due
to water intoxication and concurrent use of clozapine should be considered in the
differential diagnosis of rhabdomyolysis, especially in the severely
psychiatrically disabled population.
PMID- 9762379
TI - Novel antipsychotics and patient care in state hospitals.
AB - OBJECTIVE: To review and highlight the opportunities and challenges of
pharmacologic advances in the use of antipsychotics for the state hospital
system. METHODS: A critical review was performed of studies published either as
articles or abstracts, on the use of novel antipsychotics, particularly as they
relate to the patient population within the state mental hospital system.
FINDINGS: The recent availability of new antipsychotic medications within state
facilities has resulted in more progressive treatment, reduced recidivism (and
consequently cost savings), and preliminary evidence of preferential and superior
treatment response in specific patient subgroups (e.g., those with aggression).
At the same time, inpatient pharmacy budget increases and uncertainty in guiding
the use of novel antipsychotics have influenced the availability of these agents
in state hospitals. CONCLUSIONS: State hospital services have, by and large,
embraced the developments in pharmacotherapy of schizophrenia. Optimal use of
these new agents in this population requires additional information on their
relative efficacy in specific patient subgroups.
PMID- 9762380
TI - Update on drug interactions with azole antifungal agents.
AB - OBJECTIVE: To review and update the incidence, mechanism, and clinical relevance
of drug interactions with itraconazole, ketoconazole, and fluconazole. DATA
SOURCES: Literature was identified by MEDLINE search (from January 1990 to May
1997) using the name of each antifungal and the term "interaction" as MeSH
headings. Abstracts were identified by literature citation and by review of
Interscience Conference on Antimicrobial Agents and Chemotherapy from 1995 to
1996. STUDY SELECTION: Randomized, controlled, double-blind studies were
emphasized; however, uncontrolled studies and case reports were also included. In
vitro data were selected from literature review and citations. DATA EXTRACTION:
Data were evaluated with respect to study design, clinical relevance, magnitude
of interaction, and recommendations provided. DATA SYNTHESIS: The incidence of
fungal infections and consequent azole antifungal usage continues to increase. By
virtue of their antifungal mechanism (i.e., inhibition of cytochrome P450 fungal
enzyme systems), azoles have been investigated and implicated in several drug
interactions. The magnitude of interactions can vary from trivial to potentially
fatal, and also vary with specific azole and interactant. CONCLUSIONS: The azole
antifungal agents represent a commonly used class of agents with a broad range of
potential interactions. Recent data have increased our understanding of drug-
drug interactions with azoles. Pharmacists are in a unique position to identify
these interactions and to intervene to decrease their morbidity and improve
patient care.
PMID- 9762381
TI - Management of end-stage renal disease in children.
AB - OBJECTIVE: To review the medical literature on management of end-stage renal
disease (ESRD) and its complications in the pediatric patient. DATA SOURCES AND
STUDY SELECTION: MEDLINE searches (1970-1997) of the English-language literature.
Clinical trials and reviews of drug therapy management were included, and
bibliographies were reviewed for relevant articles. DATA SYNTHESIS: Principles of
renal replacement therapy in children have been expanded to include maintenance
of fluid and electrolyte balance and to manage the complications of ESRD in
children. Types of renal replacement and their complications are reviewed.
Complications of ESRD are reviewed with emphasis on drug therapy management of
anemia of chronic renal failure, growth retardation, and hypertension. A
discussion of the use of vitamins and supplements to maintain bone and mineral
homeostasis is provided, and specific recommendations for vaccination of children
with ESRD are given. CONCLUSIONS: Children with end-stage renal failure present a
unique challenge to the pharmacist. Renal replacement therapy for children with
ESRD involves some form of dialysis and an intensive medication regimen.
Complications must be treated with appropriate drug therapy. Drug therapy must be
monitored closely for dosage adjustment, clinical response, drug interactions,
and toxicity. Patients and families must receive continuous education and follow
up to encourage compliance. The pharmacist must work closely with the healthcare
team to optimize drug therapy and improve patient education and compliance.
PMID- 9762382
TI - Medication bezoars: a literature review and report of a case.
AB - OBJECTIVE: To describe a case of a medication bezoar and to review the clinical
presentation, diagnosis, risk factors, pathogenesis, complications, and treatment
of medication bezoars. DATA SOURCES AND STUDY SELECTION: A MEDLINE search
(January 1966-December 1997) of the English-language literature pertaining to
bezoars was performed. These articles were scanned, and literature specifically
discussing medication bezoars was selected. Additionally, the reference sections
of pertinent review and case reports were scanned for additional relevant
literature. DATA SYNTHESIS: Bezoars are concretions of foreign material within
the body. In the case of medication bezoars, these concretions occur within the
digestive tract and are composed of medications and/or medication vehicles.
Rarely, however, is bezoar formation solely due to a medication. In nearly all
reported cases the patient had one or more significant risk factors that
contributed to bezoar formation. The exact method by which medications bezoars
form is dependent on the particular type or combination of medications involved.
Bezoar formation may be associated with significant complications for the patient
due to the presence of the bezoar and because of the effects of the medication
within the bezoar. Treatment of medication bezoars depends largely on the
location and the cause of the bezoar. CONCLUSIONS: Medication bezoars are a rare
but potentially serious complication of medication use in certain patients. These
patients often present with signs and symptoms consistent with an obstruction of
the gastrointestinal tract and represent an even greater diagnostic challenge due
to the rarity of this complication. These patients also face significant
complications from both the bezoar and the medication within the bezoar. To date,
treatment of medication bezoars involves mainly physical manipulation of the
bezoar through lavage, endoscopic removal, or, in most cases, surgical removal.
PMID- 9762383
TI - Drug and environmental factors associated with adverse pregnancy outcomes. Part
II: Improvement with folic acid.
AB - OBJECTIVE: To provide a comprehensive review of periconceptional folic acid
supplementation and factors affecting folate supplementation trials. DATA
SOURCES: A MEDLINE search was conducted through December 1997. Additional sources
were obtained from Current Contents and citations from the references obtained.
Search terms included folate, folic acid, neural tube defect, spina bifida, and
anencephaly. STUDY SELECTION: Relevant animal and human studies examining the
effects of folate were reviewed. DATA EXTRACTION: Data collected included: type
of study, folate dosing, dietary folate intake, serum and red blood cell folate
concentrations, type of defect(s) studied, vitamin usage, parental risk factors,
factors affecting trial results. DATA SYNTHESIS: Nine key factors have been
identified that affect outcomes of folic acid supplementation trials. Daily doses
of 0.8 mg decreased the occurrence and doses of 4 mg decreased the recurrence of
neural tube defects in randomized clinical trials. Since lower folic acid doses
were effective in nonrandomized trials, research is needed to determine the
lowest effective dosage. Other benefits involving pregnancy outcome are
suggested. CONCLUSIONS: Women of childbearing age should take a daily folic acid
supplement to reduce the risk of pregnancies resulting in infants with a neural
tube defect and other potential adverse pregnancy outcomes. Further health
benefits from folic acid supplementation are reviewed in Part III of this series.
PMID- 9762384
TI - Providing patients with written medication information.
AB - OBJECTIVE: To review the literature and provide recommendations for the
development and dissemination of written medication information to patients and
their care providers. DATA SOURCES: A MEDLINE search (1966-1997) of the English
language literature was performed to identify articles pertaining to the
development or use of written medication information. A search of the Internet
was conducted by using Yahoo as the guide and "medication information" as the
search term. Additional resources were obtained through texts, bibliographies,
and catalogs from medical publishers. DATA EXTRACTION: Reports documenting the
creation and use of written medication information systems were reviewed, as well
as studies of readability and reading skills assessment. Examples of materials
available for purchase by laypeople and healthcare providers were also examined.
DATA SYNTHESIS: Current statistics support the widespread availability of written
medication information for patients and care providers. The goal set forth by the
Food and Drug Administration of having 75% of patients receive written
information by the year 2000 appears achievable. However, there are still many
issues to address. Content is not standardized, and materials are frequently
written at reading levels higher than that of the average patient. The
development and use of resources requiring only minimal reading skills and an
increase in the availability of materials written in Spanish are needed.
CONCLUSIONS: Written medication information provides a useful addition to
counseling by healthcare professionals. A wide variety of prepared materials is
available, as well as resources for those interested in developing tools for a
specific patient, population, or setting. Healthcare professionals should be
aware of the limitations of some resources. Content and readability must be
appropriate for the intended audience for these tools to serve a useful role in
patient education.
PMID- 9762385
TI - Calcium in corticosteroid-induced osteoporosis.
PMID- 9762386
TI - Treatment of croup with glucocorticoids.
AB - Croup is a common upper airway disease in children that can range from mild and
self-limiting to severe and fulminating. Typical treatment in the past has been
mist therapy, although its effectiveness is still being debated. Studies have
been published evaluating the efficacy of oral, nebulized, and intramuscular
dexamethasone and nebulized budesonide, in a number of combinations and
concentrations, in patients ranging in age from 3 to 72 months. The majority of
the subjects in the studies were males and more than one-third of the patients in
one study previously had croup. The studies have consistently pointed out that
the use of oral, intramuscular, and nebulized steroids have been beneficial in
patients with varying severity of croup. Nebulized budesonide has been shown to
be effective, but is not currently available in the US. Based on this
information, intramuscular or oral dexamethasone has been shown to be effective
and, in some studies, safe and could be administered to patients presenting with
moderate-to-severe croup.
PMID- 9762387
TI - Clinical aspects of gene therapy.
PMID- 9762388
TI - Indomethacin is inappropriate for use in the geriatric population.
PMID- 9762389
TI - Comment: use and abuse of flunitrazepam.
PMID- 9762390
TI - Comment: hyponatremia with venlafaxine.
PMID- 9762391
TI - [When and how to treat sarcoidosis].
PMID- 9762392
TI - [Smoking prevention in the school: results of a 3-year program].
AB - Tobacco use poses one of the greatest health problems at school. Its prevention
through health education should be assumed up by all members of the school
community and health personnel (especially family and respiratory physicians). We
designed an anti-tobacco program lasting three years aimed at all the students of
the 6th, 7th and 8th grades at school as well as those in the pre-university
years that was implemented in a rural area. This study reports the results of the
attitudes of the 610 students (256 boys and 354 girls, between 11 and 20 years
old) collected at the end of the program. 59.4% of the boys and 44.1% of the
girls reported having smoked on some occasion. The mean age at the time of the
first contact with tobacco was 11.8 +/- 2.4 years, this being significantly
different between the boys and the girls. The main reasons for starting to smoke
tobacco were quoted as peer pressure (57.1%) and curiosity (55.5%). That their
parents smoked was only adduced as a reason by 29.5% of the students. Knowledge
of the harmful effects of tobacco was limited and only 57% related tobacco
smoking to lung cancer and only 41% to coronary pathology. At the end of the
program 13.6% of the students involved smoked. 93.9% of those who quit smoking
related this event to the program. Of those still smoking, 63.6% said they would
like to quit. This justifies the need to reinforce the knowledge that will allow
them to switch attitudes and stop smoking. Intervention programs in school
populations have proved to be useful in the struggle to decrease smoking among
school children. If an adolescent can avoid smoking it is likely that s/he will
not smoke in adulthood. It is necessary to further develop this type of anti
tobacco program as reflected in this paper.
PMID- 9762393
TI - [Thoracic stab wounds].
AB - Stab wounds are the most common cause of open chest wounds in our setting, with
an incidence far higher than either wounds caused by firearms or bull horns. We
describe a series of 49 patients, 44 (89.8%) men and 5 (10.2%) women. Mean age
was 31 years. The 49 patients had suffered 72 stab wounds to the chest, of which
30 (41.6%) were penetrating and 42 (58.3%) were non penetrating. The lesions
observed were 11 (22.4%) cases of pneumothorax, 10 (20.4%) of hemopneumothorax, 6
pulmonary lesions, 2 heart wounds and 1 extensively damaged diaphragm. Twenty
four patients with non penetrating wounds and 8 with penetrating wounds were
treated conservatively. It was subsequently necessary to drain the chest of only
one. Of the remaining penetrating wounds, drains were inserted in six immediately
and 11 underwent surgery. Complications developed in only 9 cases. One patient
died as a result of abdominal lesions resulting from stab wounds directly to the
abdomen. We are in favor of conservative management. Indications for more
aggressive intervention are hypovolemic shock, cardiac tamponade or significant
loss of fluid through the thoracic drain.
PMID- 9762394
TI - [Characteristics of tuberculosis in a tertiary hospital during the years 1993
1996. Influence of the coinfection with HIV].
AB - To assess and compare epidemiological factors, clinical and radiological signs,
laboratory results and drug resistance in patients with tuberculosis (TB) with
and without AIDS. Retrospective study of TB diagnosed bacteriologically between
January 1993 and December 1996 at Hospital Universitario La Fe. Annual rates were
41.7, 47.1, 34.6 and 43.8 per 100,000 inhabitants in 1993 to 1996, respectively.
AIDS was present in 22.4%. TB was pulmonary in 87% and 49.4% in patients without
and with AIDS, respectively. Incidence was higher in the 25 to 34 age range.
Prior contact with TB patients was established in 19.2% of cases. Pulmonary TB in
patients with AIDS presented with normal lung X-rays in 30.1%; 16.2% of these had
positive sputum cultures. Pulmonary cavitation was evident in 32.6% of TB
patients without AIDS and 6.8% of those with AIDS. Pulmonary TB was diagnosed by
culture of sputum taken at the time of admission in 25.9% of non AIDS patients
and in 12.4% of patients with AIDS. Extrapulmonary TB was diagnosed by culture in
most cases. Such forms predominated among TB plus AIDS patients, with most cases
being ganglial and urogenital. Overall drug resistance was 8.3% (7.4% non
AIDS/11.5% AIDS). Primary resistance (PR) was 6.3% and 7.1%, PR to hydrazides was
5% and 5.4%, and secondary resistance was 32.4% and 33.3%. Drug resistance in non
AIDS and AIDS patients, was associated with a history of TB and past treatment (p
< 0.009), prior contact with TB patients (p < 0.004) and pulmonary cavitatin (p <
0.02). TB with AIDS tends to occur in a younger population, is often
extrapulmonary or with atypical lung involvement. Drug resistance is similar in
patients with and without AIDS.
PMID- 9762395
TI - [Relationship between tobacco smoke exposure and the concentrations of
carboxyhemoglobin and hemoglobin].
AB - To determine the carboxyhemoglobin (CO-Hb) predictive intervals in active and
passive smokers and to obtain an equation expressing the relation of CO-Hb to
number of cigarettes smoked, we studied 233 outpatients referred to an urban
university hospital for arterial gas measurement. Patients were excluded if they
were receiving oxygen therapy or had been hospitalized in the two months before
the study. The patients were classified as non smokers (57), passive smokers
(54), smokers of less than 11 cigarettes (22), smokers of 11 to 20 (41) smokers
of 21 to 40 (44) and smokers of over 40 (15). All patients answered a
questionnaire on exposure to tobacco smoke or other sources of CO. Blood gases
and co-oximetry were measured in all patients. Mean CO-Hb and 95% confidence
intervals were 1.53% (0.78-1.85%) in smokers and 2.59% (1.89-3.29%) in passive
smokers. The linear equation that best expressed the relationship was CO-Hb =
0.153 x number of cigarettes + 1.1 exposure to other sources (1 or 0) + 1.39 (SD
0.84)%. Hemoglobin level was significantly higher in the two groups smoking more
than 21 cigarettes. We conclude that the predictive intervals is 1.9% in non
smokers who are not exposed to other sources of CO. Passive smokers have
significantly higher levels of CO-Hb than non smokers. Heavy smokers have
polycythemia.
PMID- 9762396
TI - [Respiratory disease in the immigrant].
PMID- 9762397
TI - [Antipneumococcal vaccines. Old controversies and new indications (II)].
PMID- 9762398
TI - [Atypical carcinoid tumor of the thymus].
AB - We report a male patient with atypical carcinoid tumor diagnosed by anterior
mediastinotomy and biopsy after a mass was observed by chance on a chest film.
The presence of neuroendocrine markers, notably chromogranin, cytokeratin,
synapto-physin and neuro-specific enolase, facilitated diagnosis. Because the
tumor was infiltrative, full surgical excision and radiotherapy to the
mediastinum (50 Gy) were provided. We describe the incidence, clinical
presentation, diagnosis, treatment and prognosis of these tumors.
PMID- 9762399
TI - [Benign fibrous mesothelioma: report of 8 cases].
AB - Benign fibrous mesothelioma (BFM) is a primary, isolated tumor of the pleura. In
80% of patients the tumor originates in the visceral pleura. BFM is rare and
localized malignant mesothelioma, whose prognosis and treatment is significantly
different, must be considered as a differential diagnosis. We report 8 cases of
BFM excised by thoracotomy. In 6 asymptomatic patients, diagnosis was based on
radiological images. One patient with a large tumor suffered dyspnea, acropachia
and hypertrophic osteoarthropathy. The last patient experienced long-lasting
chest pain even though the tumor was small (3 x 3 x 1 cm). Diagnosis was before
thoracotomy in 3 cases, 2 by punch biopsy (tru-cut) and the other by
thoracoscopy. The results of pleural fluid analysis were nonspecific in 2 of the
3 cases in which pleural effusion was present. Thoracotomy allowed removal of the
entire tumor in all patients.
PMID- 9762400
TI - [Esophagocele: a complication of the bipolar exclusion of the esophagus].
PMID- 9762401
TI - [Cavitated chronic eosinophilic pneumonia with increased serum IgE. Is its
differentiation from Churg-Strauss vasculitis possible?].
PMID- 9762402
TI - [Cystic pulmonary disease: a rare form of sarcoidosis].
PMID- 9762403
TI - [Cervical pulmonary hernia].
PMID- 9762404
TI - [Directly observed treatment of tuberculosis].
PMID- 9762405
TI - A proposed estimate of the tumor aggressiveness of human breast cancer using
radiorespirometry.
AB - The relationships between carcinomatous aggressiveness and the glucolytic
metabolism, namely the rate of 14CO2 production from [U-14C] glucose, are
obtained from human breast tissues using radiorespirometry. The values are
estimated as the initial velocity (V) expressed in eta 14CO2 x min-1 x g-1 of
fresh tissues by [U-14C] glucose metabolism. The aggressiveness of the breast
carcinomatous is diagnosed by the SBR grade system. As two control normal
tissues, (V) are 0.86 to 0.90 from non-cancer patients. In carcinomatous tissues
(Vc), there is an increase from 1.53 to 3.14, but in the corresponding
surrounding non-cancer tissues (Vn) these show a decrease from 2.20 to 0.22 for
SBR I, SNR II to SBR III. The ratio between (Vc) and (Vn) are found, according to
carcinomatous aggressiveness, as 1.45 to 1.54, 1.69, 2.35 to 2.86 and 4.82 to
10.38 respectively for SBR I, lobular carcinoma, SBR II and SBR III; while the
ratio is 1.04 for the normal tissue which come from non-cancer patients. The
above results suggest the possibility of assessing the carcinomatous
aggressiveness by radiorespirometry before a histopathological diagnosis, even in
a lower aggressiveness as in SBR I cases which are difficult to diagnose and
manage.
PMID- 9762406
TI - Constitutive nitric oxide synthase in Saccharomyces cerevisiae.
AB - After removing nonspecific immunoreactivities from crude extract by
immunoaffinity chromatography, an immunoreactive-band at 60 kDa of constitutive
nitric oxide synthase (cNOS) from Saccharomyces cerevisiae was detected by
Western blot using mouse monoclonal anti-neuronal NOS (cNOS). The activity of
yeast cNOS, which was prepared by either histone-agarose chromatography or anti
neuronal NOS immunoprecipitation, was monitored by the formation of citrulline.
Yeast cNOS was activated in the presence of calmodulin and arginine, whereas it
was inhibited by L-NAME, a mammalian NOS inhibitor. Moreover, actinomycin-D
decreased the extracellular and the intracellular levels of nitrate and nitrite
which had been converted from NO. The results suggest that cNOS occurs in
unicellular eukaryotes and the enzyme activity can be regulated.
PMID- 9762407
TI - The potential role for CDC42 protein from rat brain cytosol in phospholipase D
activation.
AB - Phospholipase D (PLD) has been extracted from rat brain membranes and
chromatographically enriched 70-fold. From the rat brain cytosol, Cdc42 with a Mr
of about 24,000 and ADP-ribosylation Factor (Arf) with a Mr of about 18,000 have
been purified to near homogeneity. PLD was activated better by purified cytosolic
Arf than by the other small G proteins tested. Cdc42 purified from rat brain
cytosol showed 70% of PLD activation activity exerted by cytosolic Arf,
suggesting that Cdc42 may be one of the major G proteins involved in the
activation of membrane-associated PLD. While Cdc42 or RhoA exhibited synergistic
activation of PLD when administered in conjunction with Arf, Cdc42 and RhoA
showed an additive effect when used together. It is possible that Arf and Rho
family proteins may have different interaction sites on PLD. These findings
support a role for GTP-binding proteins of the Rho family as well as Arf in the
activation of membrane-associated PLD and further suggest that Cdc42 may be a
major G protein involved in the PLD activation in rat brain.
PMID- 9762408
TI - Lower arachidonic acid content and preferential beta-oxidation of arachidonic
acid over palmitic acid in tumour cell lines as compared to normal lymphoid
cells.
AB - In several studies certain polyunsaturated fatty acids (PUFA) have been shown to
be selectively tumouricidal or suppressive of tumour cell proliferation. The
mechanism behind this phenomenon likely involves peroxidation of the PUFA and
generation of free radicals to which tumour cells seem to be more sensitive than
normal cells. In this report we have measured the total lipid content in
separated lymphoid cells and several tumour cell lines, among which, T-cell
leukaemia, monocytic leukaemia, melanoma, fibrosarcoma, lung carcinoma and colon
adenocarcinoma are included. Generally these tumour cell lines contain only one
half to one third of the relative amount of arachidonic acid (AA) as compared to
freshly prepared lymphocytes and monocytes or lymphocytes kept in culture.
Furthermore, when we measured the beta-oxidation in long term incubation of [1
14C] AA and compared it with that of [1-14C] palmitic acid we found that several
of the tumour cell lines showed a preference for AA over palmitic acid in the
tumour cell lines whereas the opposite was observed for normal lymphoid cells.
PMID- 9762409
TI - A human B cell line AF10 expressing HIL-17.
AB - AF10, a human B cell line, is a mycoplasma-free variant cloned from the human IgE
myeloma cell line U266. Total RNA isolated from the AF10 cells was used as
template for RT-PCR, and a specific product of about 411bp corresponding to the
coding region of hIL-17 lack of a leading sequence obtained. The sequence of the
RT-PCR product is the same to that reported in the literature. The expressed rhIL
17 in E. coli can induce 10- to 15-fold increase of IL-6 secretion by mouse
fibroblast 3T3 cells. It is for the first time until now that hIL-17 messager has
been detected in B cell. There may exist some potential relationship between hIL
17 and myeloma cells.
PMID- 9762410
TI - Hepatic and renal metallothionein induction following single oral administration
of gallium arsenide in rats.
AB - Metallothionein genes (MT) are inducible by a variety of agents, including heavy
metals. We report the induction of MT expression by gallium arsenide (GaAs), a
superior intermetallic semiconductor material at two time intervals following
single oral exposure in rats. The data is also supplemented with two additional
groups exposed to gallium (III) as gallium oxide and arsenic (III) as sodium
arsenite to determine which of the two moieties in GaAs is responsible for any
such possible effects. The results indicate that GaAs administration does
significantly induces MT in hepatic tissues accompanied by an increase in
cytosolic glutathione, arsenic, zinc and copper concentration. It thus proves
that arsenic moiety is chiefly responsible for such an effect.
PMID- 9762411
TI - Spin trapping for nitric oxide produced in LPS-treated mouse using various new
dithiocarbamate iron complexes having substituted proline and serine moiety.
AB - Four dithiocarbamate derivatives of 4-substituted L-proline and N-methyl-L-serine
were synthesized, and their iron complexes were prepared in Tris-HCl buffer
solution. These complexes were used as spin trapping reagents for nitric oxide in
ESR spectrometry, and compared with each other in regard to their spin trapping
properties in vivo. When the synthesized complexes were injected to
lipopolysaccharide-treated mice intravenously, the nitric oxide adducts were
detected both in the liver and in the blood except N-dithiocarboxy-4
(methoxymethyl)oxy-L-proline iron complex, whose nitric oxide adduct was detected
mostly in the blood. When the exogenous nitric oxide adduct of this complex was
injected, it was not detected in the liver, too. It is considered that this
complex can trap nitric oxide in the blood by excluding the accumulation of the
nitric oxide adduct in the liver.
PMID- 9762412
TI - Modulation of MAP kinase signaling and growth characteristics by the
overexpression of protein kinase C in NIH3T3 cells.
AB - This study was performed to examine effects of the overexpression of protein
kinase C (PKC) isoforms (i.e., beta I, beta II, gamma, delta, eta, and zeta) on
mitogen-activated protein (MAP) kinase (Erk-1 and -2) signaling and growth
characteristics of NIH3T3 cells. Phorbol ester (PMA) activated endogenous and
ectopically expressed PKC alpha, beta I, beta II, gamma, delta, epsilon, and eta.
Overexpression of the examined PKC isoforms enhanced PMA-induced MAP kinase
activation. Potentiation of MAP kinase activation was also observed upon
stimulation of cells with platelet-derived growth factor (PDGF) although there
was no indication for the activation PKC isoforms by PDGF. Inhibition of PKC
blocked PMA- but not PDGF-induced MAP kinase activation. Thus, potentiation of
PDGF-induced MAP kinase activation appears to be independent to PKC activity,
while PMA-induced MAP kinase activation requires PKC activity. The ability of PKC
isoforms to potentiate MAP kinase activation is not related to the growth
characteristics of cells because individual PKC isoforms differentially regulated
maximum density and proliferation of cells.
PMID- 9762413
TI - RGD-containing trypsin with both platelet aggregation inhibitory activity and
proteolytic activity.
AB - Arg-Gly-Asp (RGD) motif mediates cell adhesion as a major determinant in
interactions of disintegrins with cell surface receptors. In order to obtain a
mutant trypsin with both high affinity to integrins and retained proteolytic
activity, RGDS and RGD were inserted into a rigid turn region and a flexible loop
of trypsin, respectively. Wild type trypsin and substituted mutant trypsins,
37RGDS and 77RGD, were expressed in E. coli and purified. Kinetic properties,
autolytic stability as well as platelet aggregation inhibitory activity of both
37RGDS and 77RGD were determined. 37RGDS and 77RGD give retained proteolytic
activities of 34% and 87%, respectively, and both become less stable to
autolysis. 37RGDS shows an obvious inhibition rate of 29% for platelet
aggregation and 77RGD gives a rather weak rate of 14% at the same protein
concentration of 3.5 microM, while the wild type trypsin shows no inhibitory
activity.
PMID- 9762414
TI - Effect of cholesterol/phospholipid ratio on stimulatory GTP-binding protein
function.
AB - The effect of different cholesterol/phospholipid (C/P) ratios on the coupling
function between stimulatory GTP-binding protein(Gs) and adenylyl cyclase (AC) in
proteoliposomes, and its relationship to the conformational change of Gs were
investigated. The results showed that Gs activities of both binding GTP gamma S
and stimulating adenylyl cyclase were the highest in proteoliposomes with a
proper content of cholesterol similar to physiological situation while the lowest
with higher cholesterol content similar to pathological situation. In addition,
the conformational change of Gs in proteoliposomes was also detected by steady
state and nanosecond time-resolved fluorescence using acrylodan as a probe. It is
suggested that a proper C/P ratio similar to physiological situation regulates
the function of Gs by inducing a change in the physical state of lipid bilayer,
which would favor the formation of a suitable conformation of Gs with higher
activities of both binding GTP and stimulating adenylyl cyclase. But if C/P ratio
is higher, such as in pathological situation, this is unfavorable for motion of
Gs in membrane, which results in inhibition of Gs function significantly.
PMID- 9762415
TI - Monoclonal antibodies directed against lipopolysaccharide of Legionella
pneumophila serogroup 1.
AB - The monoclonal antibodies (MAbs) against lipopolysaccharide of virulent strain of
Legionella pneumophila serogroup 1 were produced. Three most productive hybrid
clones (5F4, 5F10 and 2C9) were selected from fusions of mouse myeloma cells with
spleen cells from BALB/c mice, immunized with bacterial outer membrane antigens.
All generated clones were IgG-secreting. The MAbs had narrow strain specificity
and showed no cross-reactions with other unrelated bacterial species. These
antibodies were tested in sandwich ELISA. The results suggest that the MAbs could
be used for diagnostic purposes.
PMID- 9762416
TI - TNF alpha-induced aerobic synthesis of ATP on plasma membranes of target cells.
The relation to the expression of the nuclear oncogene c-myc.
AB - The accumulation of ATP by preparations of plasma membranes enriched particles
(PMEP) isolated from rat hepatocytes, murine splenocytes and human T-lymphocytes
has been investigated after the binding of human and murine tumour necrosis
factors (TNF alpha) to their specific receptors. The TNF alpha-induced expression
of the nuclear oncogene c-myc in intact hepatocytes has been also studied. TNF
alpha induced the marked biosynthesis of ATP on PMEP of hepatocytes and
splenocytes within the first minute of incubation. The biosynthesis of ATP was
independent of the activity of adenylate kinase and only occurred in the presence
of all the components of aerobic phosphorylation and the electron acceptor,
cytochrome C or diferric transferrin. The level of ATP on PM correlated with the
degree of expression of the nuclear oncogene c-myc in the same target cells.
Adriamycin totally suppressed the biosynthesis of ATP on PM and simultaneously
inhibited the expression of c-myc. The ATP synthesized on PM is suggested to be
involved in transduction of the proliferative or growth signal to the cell
nucleus.
PMID- 9762417
TI - Epitope mapping of anti-troponin I monoclonal antibodies.
AB - Two groups of monoclonal antibodies (MAbs) specific to human cardiac troponin I
(cTnI) were generated by immunization of mice by isolated cTnI (group I, 16 MAbs)
or by the whole troponin complex (group II, 15 MAbs). Two sets of overlapping
decapeptides covering the complete sequence of cTnI were prepared and used for
epitope mapping by SPOT technique. Majority of MAbs (28 out of 31) interacts with
synthetic peptides thus indicating that they recognize liner epitopes. MAbs
raised against isolated cTnI preferentially recognize epitopes located at the N-
or C-terminal ends of cTnI. Nine out of fifteen MAbs raised against whole
troponin complex interact with epitopes located in the N-terminal part of cTnI.
Generation of MAbs recognizing both isolated cTnI and cTnI inside of troponin
complex and mapping their epitopes provides reliable detection of TnI in serum of
patients with acute myocardial infarction.
PMID- 9762418
TI - The effect of interferon therapy on erythrocyte membrane Na+,K+ ATP activity in
patients with chronic hepatitis B and C virus infections.
AB - In order to evaluate the effect of alpha interferon on erythrocyte membrane
Na+,K+ ATPase (EC 3.6.1.37) activity, 10 patients with chronic hepatitis B virus
(HBV) infection and 8 patients with chronic hepatitis C virus (HCV) infection
were investigated. Erythrocyte membrane Na+,K+ ATPase activity was determined in
controls and in patients with HBV and HCV infection. Na+,K+ ATPase activity was
significantly less in untreated patients with (HBV) infection (n = 20; 0.134 +/-
0.073 mumol of phosphate produced per milligram of protein per hour) and (HCV)
infection (n = 11; 0.144 +/- 0.049) when compared to the controls (n = 10; 0.219
+/- 0.055). Among these subjects patients were treated with interferon and
following treatment, significant elevation of Na+,K+ ATPase activity was seen in
patients with HCV (n = 8; 0.183 +/- 0.044; P = 0.049) and HBV (n = 10, 0.213 +/-
0.095, P = 0.0069) infections when compared with the pre-treatment values (n = 8;
0.152 +/- 0.050) and (n = 10, 0.131 +/- 0.083), respectively. Normalization of
serum alanin amino transferase levels (ALT) at treatment cessation was seen in 8
of 10 (%80) HBV infected patients of whom 2 of 8 (%25) had sustained ALT
responses within three months after the end of treatment. In HCV infected
patients 1 of 8 (%12.5) had sustained response following treatment. At the end of
treatment, although Na+,K+ ATPase was restored in both of the patients groups,
relative changes in enzyme activity in relation to relative reduction in ALT
levels as a response to IFN therapy were not correlated.
PMID- 9762419
TI - Activation of apoptotic caspase-3 and nitric oxide synthase-2 in buccal mucosa
with chronic alcohol ingestion.
AB - Apoptosis, the process of programmed cell death, involves activation of caspase
proteases cascade that remains under the regulatory control of nitric oxide. In
this study, we investigated the activity of a key apoptotic protease, caspase-3,
and the expression of nitric oxide synthase-2 (NOS-2) associated with buccal
epithelial cells apoptosis induced by chronic ethanol diet. The assays revealed
that a 7.9-fold enhancement in buccal epithelial cells apoptosis, observed in the
alcohol diet group, was accompanied by a 37.6-fold increase in caspase-3 activity
and a 10.1-fold increase in NOS-2. Furthermore, the expression of NOS-2 showed a
positive correlation (r = 0.92) with the extent of changes induced in caspase-3
activity. These results implicate caspase-3 in the process of alcohol-induced
epithelial cells apoptosis, and point towards participation of NOS-2 in the
amplification of the cell death signaling cascade.
PMID- 9762420
TI - A comparative study by a single chromatographic procedure of glycolytic
regulatory kinase isozymes in rat erythroid cells as a function of
differentiation-maturation process.
AB - The isozymes of three glycolytic regulatory kinases: hexokinase,
phosphofructokinase and pyruvate kinase are fractionated by a single ion exchange
chromatographic procedure on DEAE-cellulose. Enriched-erythroblast bone marrow
cells showed two heterogeneous peaks, each consisting of two overlapping peaks:
one major and one minor peak, but only two isozymes were observed in
reticulocytes and erythrocytes. Phosphofructokinase showed multiple isozymic
forms in the three cell populations, but while in erythroblasts the main one
eluted in the last fractions, in reticulocytes and erythrocytes it eluted in the
early fractions. Pyruvate kinase showed a main early activity peak with a
shoulder in erythroblasts, reticulocytes and erythrocytes but the response to the
allosteric effectors (fructose-1,6-bisphosphate and ATP) suggests the presence of
different pyruvate kinase isozymes in reticulocytes and erythrocytes.
PMID- 9762421
TI - Glutathione metabolism and glutathione S-conjugate export ATPase (MRP1/GS-X pump)
activity in cancer. I. Differential expression in human cancer cell lines.
AB - Mg(2+)-dependent vanadate-sensitive glutathione S-conjugate ATPase (GS-X pump)
activity is a common feature of some ATP-binding cassette (ABC) transporters,
such as the multidrug resistance-associated protein (MRP1) gene product, that
exports biologically active electrophiles after their conjugation with
intracellular glutathione (GSH) from normal and cancer cells. Antitumor
electrophiles (e.g. naturally occurring cyclopentenone prostaglandins and
anticancer chemicals) can be intracellularly conjugated with GSH via a
glutathione S-transferase catalyzed reaction and be eliminated through GS-X pumps
thus threatening cancer chemotherapeutics. Since different sensitivities to
antitumor electrophiles are shown by different cell types, the ability of several
human cancer cell lines to produce and export S-(2,4-dinitrophenyl)-glutathione
(DNP-SG) conjugate through the GS-X pump, using whole cells and inside-out
membrane vesicle preparations, is investigated. Different cancer cell lines
exhibited characteristically different GS-X pump activity. In particular, HEp-2
larynx carcinoma cells possess an elevated DNP-SG export rate through the GS-X
pump compared with HeLa, K562, U937 or HL-60 cells, which exhibit the lowest
activity. The differences in DNP-SG export rates are not due to decreased
glutathione S-transferase activity or impaired de novo synthesis of GSH. The
findings suggest that the GS-X pump may be involved in the modulation of the
biological activity of both naturally occurring electrophiles and anticancer
drugs. The differential expression of GS-X pumps may lead to an improved
understanding of multidrug resistance and may be exploited in the development of
new therapeutic strategies for the treatment of cancer patients.
PMID- 9762422
TI - Glutathione metabolism and glutathione S-conjugate export ATPase (MRP1/GS-X pump)
activity in cancer. II. Cell-to-cell variability, relation with cellular
activation state and functional absence of GS-X pump in lymphocytes.
AB - A severe complication in late-stage cancer patients is host immunosuppression. It
is suggested that overproduction of the highly cytostatic and cytotoxic
antiproliferative cyclopentenone prostaglandins (CP-PGs) within the plasma of
cancer-bearing subjects may contribute to immunosuppression. Lymphoid tissues of
Walker 256 tumor-bearing rats accumulate large amounts of CP-PGs while the tumor
tissue itself does not. Moreover, tumor cells may present differential
sensitivity to CP-PGs due to the expression of the multidrug resistance
associated protein (MRP1) gene product which shows a Mg(2+)-dependent vanadate
sensitive glutathione S-conjugate export ATPase (GS-X pump) activity that
extrudes CP-PGs from cells as glutathione S-conjugates. In this study, the
possibility that deficient GS-X pump activity in immune cells that may be
involved in the accumulation of CP-PGs is investigated. Rat lymph node
lymphocytes do not exhibit any notable activity even when mitogen-stimulated.
Conversely, although rat peritoneal resident (quiescent) or thioglycollate
stimulated (inflammatory) macrophages exhibit low GS-X pump activity, Bacillus
Calmette-Guerin (BCG)-activated macrophages show a notable rise in the activity
of the ATPase, suggesting that the cellular activation state may modulate GS-X
pump activity/expression and that, under appropriate stimuli (e.g., during immune
response) macrophages may provide a self-defense against electrophilic CP-PGs by
forming GS-conjugates that can be extruded from cells through the GS-X pump. ras
oncogene expression may be linked with MRP1/GS-X pump expression/activity, since
C2C12 promyoblasts transformed by v-H-ras transfection doubled GS-X pump
activity. These results support the proposition that the accumulation of CP-PGs
and the immunosuppression of tumor-bearing subjects may be attributed to a lack
of GS-X pump activity/expression in lymphocytes.
PMID- 9762423
TI - Effects of the antiproliferative cyclopentenone prostaglandin A1 on glutathione
metabolism in human cancer cells in culture.
AB - Homeostatic mechanisms for the maintenance of glutathione (GSH) are fundamental
in the provision of a cellular defense against electrophilic/oxidant challenges.
Cyclopentenone prostaglandins (CP-PGs) are powerful antiproliferative endogenous
substances that may act as electrophilic regulating compounds, by virtue of the
presence of an alpha,beta-unsaturated carbonyl group in the cyclopentane ring.
Nevertheless, differential resistance to CP-PG cytotoxic/cytostatic effect has
been reported in different cell types. It is reported that the
activity/expression of gamma-glutamylcysteine synthetase (gamma-GCS, the rate
limiting enzyme in GSH biosynthesis) can be inducibly activated by electrophiles,
including CP-PGs. The response of the human cancer strains HEp-2 (larynx
carcinoma) and HL-60 (promyelocytic leukemia) cells to treatment with the CP-PG
PGA1 in culture was investigated by evaluating the time-course of GSH synthesis
and activity of enzymes of GSH metabolism, other than gamma-GCS, after PGA1
addition. HEp-2 cells, being more resistant to PGA1 cytotoxic and cytostatic
effects, have basal GSH levels that were 2.4-fold higher than that of HL-60
cells. The activities of GSH S-transferase (GST), glutathione reductase (GSRd)
and glutathione peroxidase (GSPx) are constitutively higher in HL-60 cells than
in HEp-2 cells (respectively, 17.0-, 28.5- and 12.3-fold). When challenged with
PGA1, both cell types exhibited a dose-dependent rise in GSH content that was
maximal 18 h after PGA1 addition and was preceded by a rise in GST and GSRd
activities in both cell types (at 12 h). GSPx activity increased only in HEp-2
(PGA1 evoked a 93.4%-inhibition in HL-60 cells). Moreover only HEp-2 cells
exhibited early capacity to enhance GSH content (1-2 h just after PGA1 addition).
These results and earlier data showing that leukemia cells are sensitive to CP-PG
treatment suggest that deficiencies in GSH metabolism may be strategically in
therapeutic approaches to the treatment of human leukemias.
PMID- 9762424
TI - A new PCR-based approach to a fast search of a wide spectrum of cry genes from
Bacillus thuringiensis strains.
AB - A pair of highly degenerated primers was adapted to carry out a single-step PCR
detection of any known and probably unknown cry genes of classes cry1, cry4 and
cry9 encoding for 130 kDa protein delta-endotoxins in the natural Bacillus
thuringiensis (BT) strains. The Southern hybridization of the product has
demonstrated that essentially remote cry-genes like cry1Aa and cry9A (cryIG)
could be represented in the single amplificate if they are simultaneously present
in the genome of the analyzed strain. Four genes were detected by the proposed
scheme in the BT ssp. galleriae 11-67. One of them, gene cry1Ga1 was originally
found and cloned using the PCR-amplification product obtained from the genomic
DNA of this strain as a probe. The new gene was completely identical to one
cloned by B. Lambert (unpublished, EMBL accession number Z22510) and essentially
related to cryIM (EMBL accession number Y09326), renamed according to the new
nomenclature as cry1Ga2.
PMID- 9762425
TI - Anchored oligo(dT) primers for automated dye terminator DNA sequencing.
PMID- 9762426
TI - Rapid DNA purification from agarose gels using 96-well format, centrifuge-driven
filtration.
PMID- 9762427
TI - Sodium vanadate treatment as a shortcut following alkaline phosphatase cleavage.
PMID- 9762428
TI - Photographic recording of fluorescent DNA bands on agarose gels.
PMID- 9762429
TI - Allele-specific, inverse-PCR amplification for genotyping MN blood group.
PMID- 9762430
TI - PCR-mediated mutagenesis in sequences recalcitrant to homogeneous amplification.
PMID- 9762431
TI - Repetitive elements amplified during differential display.
PMID- 9762432
TI - Use of Staphylococcus aureus protein-A sub-domains as a tag for the sensitive
detection of recombinant fusion proteins.
PMID- 9762433
TI - Purification of Ig-fusion proteins from medium containing Ig.
PMID- 9762434
TI - Inexpensive motion detectors for quantification of animal activity.
PMID- 9762435
TI - Simple blocking system for use with maleimide-labeled nucleic acid probes.
PMID- 9762436
TI - Clinical cancer trial information and specimen resources.
PMID- 9762437
TI - Peak height pattern in dichloro-rhodamine and energy transfer dye terminator
sequencing.
AB - Establishing the pattern in peak heights within local sequence contexts improves
the accuracy of base calling and the identification of DNA sequence variations in
dye-terminator cycle sequencing. We have systematically examined pairs of
sequence-tagged sites (STSs) that vary at only a single nucleotide to determine
how base changes influence the peak heights of neighboring bases in sequencing
traces generated by two recently commercialized dye-terminator chemistries, the
dichloro-rhodamine (dRhodamine) and the energy transfer (BigDye) terminators. For
sequencing traces generated with the dRhodamine terminators, the peak height of a
particular base in 28 of 64 possible 3-base windows (44%) can be predicted by
knowing just one or two bases 5' to the base in question. For those generated
with the BigDye terminators, the peak height of a particular base in 23 of 64
possible 3-base windows (36%) can be predicted by knowing the local sequence
context. When the peak heights are binned slightly differently, 75% (48 out of 64
cases) of the base peaks generated by both dRhodamine and BigDye terminators fall
in the middle half, confirming that the peak patterns of these two new dye
terminator chemistries are much more even than those found in the original
rhodamine dye terminator sequences.
PMID- 9762438
TI - Rapid acquisition of unknown DNA sequence adjacent to a known segment by
multiplex restriction site PCR.
AB - The determination of unknown DNA sequences around a known locus has important
applications in molecular genetics, specifically in genomic walking and genome
mapping. Several PCR-based methods have been reported to address this issue, but
they often involve multiple, time-consuming steps. We have previously described a
technique known as restriction site PCR (RS-PCR) that allows sequence acquisition
faster than the existing methods. The method involves PCR using four separate
universal primers that are representative of given restriction enzyme sites (RS
primers), and a specific primer from one end of the known sequence. We have now
significantly improved the technique by mixing the four universal primers into
one PCR tube with the first specific primer. This is followed by a nested PCR
with the mixed RS primers and an internal specific primer, after which the
product is sequenced by direct automated sequencing. The technique, called
multiplex RS-PCR (mRS-PCR), is reproducible and can be used to obtain unknown
sequence adjacent to known sequences in both the upstream and downstream
directions. We illustrate the application of mRS-PCR in the acquisition of
approximately 780 bp of genomic sequence starting from a known sequence of
approximately 120 bp. Multiplex RS-PCR appears to be the fastest of all methods
that address the issue of unknown sequence retrieval adjacent to a known region.
PMID- 9762439
TI - Highly sensitive northern hybridization using a rapid protocol for downward
alkaline blotting of RNA.
AB - A simple and fast RNA gel blot procedure is described that uses 50 mM NaOH to
simultaneously transfer and fix RNA to a positively charged nylon membrane. The
RNA is transferred in a downward direction, and transfer is routinely completed
within 2.5 h. The resulting blots give increased sensitivity over existing
methods without affecting RNA integrity and can be used in both radioactive and
nonradioactive detection procedures.
PMID- 9762440
TI - Limitations for purification of murine interleukin-18 when expressed as a fusion
protein containing the FLAG peptide.
AB - As a strategy to purify recombinant murine Interleukin (IL)-18, we cloned the
mature coding region of this protein into the pFLAG-1 expression system. The
intent was to use the FLAG peptide "tag" as an amino terminal addition to IL-18
so that purification of this fusion protein (FLAG-IL-18) on anti-FLAG antibody
affinity columns could be performed. While significant amounts of recombinant IL
18 were present in E. coli lysates, only a small portion of this material could
be recovered on immunoaffinity columns conjugated with an anti-FLAG antibody.
Surprisingly, the majority of recombinant IL-18 present in E. coli (strain JM83)
bacterial lysates did not contain the FLAG peptide and therefore did not bind to
immunoaffinity columns conjugated with an anti-FLAG antibody. However, we found
that the BL21 strain of E. coli, which has reduced endogenous protease activity,
could express the majority of recombinant IL-18 as the fusion protein, FLAG-IL
18. Taken together, these studies show that it is necessary to consider whether
protease sites formed at the FLAG-protein junction can be easily cleaved by the
bacterial strain used to express the fusion protein.
PMID- 9762441
TI - Isolation of differentially expressed genes by combining representational
difference analysis (RDA) and cDNA library arrays.
AB - The difference products (DP) of representational difference analyses (RDA) were
used as hybridization probes on cDNA arrays. The effectivity of RDA products
obtained with increasing driver/tester ratios (DP 1 = 100:1, DP 2 = 800:1 and DP
3 = 400,000:1) to isolate differentially expressed genes was compared with the
effectivity of conventional differential hybridizations. Pacreatic cancer and
control tissues were used as a test system to isolate differentially expressed
genes. The use of RDA products as hybridization probes showed two major
advantages: (i) a reliable identification of true differential signals; and (ii)
only one autoradiograph had to be analyzed, which eliminated the need for a
laborious subtraction of signal intensities obtained with different cDNA probes.
Increasing driver/tester ratios in iterative rounds of RDA delivered more
specific results, though the total yield of differential clones was gradually
reduced. In this situation, the intermediate RDA product DP 2 provided the best
compromise.
PMID- 9762442
TI - Fission yeast expression vectors adapted for positive identification of gene
insertion and green fluorescent protein fusion.
AB - A pYZ series of fission yeast expression vectors, derivatives of the pREP series,
was designed to allow positive identification of cloned gene insertion and fusion
to the green fluorescent protein (GFP) gene for in vivo analysis of gene
expression. To validate this new vector system, the human immunodeficiency virus
type 1 (HIV-1) vpr gene of viral isolate pNL4-3 was expressed in the pYZ1N
vector. Vpr-induced phenotypic changes were the same as those observed with vpr
expressed from pREP1N. Consistent with observations in mammalian cells, a Vpr-GFP
fusion protein localizes on the nuclear membrane of fission yeast cells.
Additionally, we were able to detect a naturally occurring mixture of vpr genes
from a plasma sample of an HIV-infected pediatric long-term surviving patient.
These pYZ vectors expedite gene cloning for general purposes and are particularly
suited for largescale random gene screening.
PMID- 9762443
TI - Quantitation of mixed-base populations of HIV-1 variants by automated DNA
sequencing with BODIPY dye-labeled primers.
AB - Direct DNA sequencing of human immunodeficiency virus type 1 (HIV-1) pol and env
gene regions was characterized for accuracy and precision. Restricted maximum
likelihood (REML) analysis of molecular clone reconstruction experiments using a
primer-walking strategy showed that the BODIPY and BODIPY energy-transfer (BET)
dye primers sets were significantly more accurate in quantitating heterogenous
base mixtures than the fluorescein/rhodamine dye primers. Of the three sets
examined, the BET dye primers were the most accurate. The improved accuracy
correlated with the reduced emission band-widths of BODIPY and BET dye primers
and the more uniform signal intensities of BET dye primers. However, comparing %
coefficients of variation (CV) for the three dye primer sets, revealed that
BODIPY dye primers gave better precision than both BET and fluorescein/rhodamine
dye primer sets. Several sequence-dependent motifs were identified that showed
specific nucleotide-biased incorporation and were determined to be the major
variable component of the total %CV. Taken together, these results show that
BODIPY and BET direct DNA sequencing can accurately and precisely characterize
complex mixed-base populations.
PMID- 9762444
TI - Large DNA fragment sizing using native acrylamide gels on an automated DNA
sequencer and GENESCAN software.
AB - We have investigated the potential of the PE Applied Biosystems Model 373
Automated DNA Sequencer and GENESCAN software to size minisatellite alleles
ranging in size from 230 bp to 2.5 kbp. We report on the use of a native (non
denaturing) acrylamide gel system and fluorescent dUTP labeling of PCR products.
The observed variability in size calling ranged from +/- 0.4-bp standard
deviation (SD) at the lower end of the size range to +/- 37.5-bp SD for the
largest allele. Both within-gel and between-gel variability in sizing increased
with larger alleles, in particular when sizes exceeded 2 kbp. Size-calling
differences were observed dependent on the method used to fluorescently label the
PCR products and with the fluorescent dye type and concentration used in
incorporation. The benefits and limitations of the current GENESCAN software in
sizing large DNA fragments are also discussed.
PMID- 9762445
TI - DAF optimization using Taguchi methods and the effect of thermal cycling
parameters on DNA amplification.
AB - Taguchi methods, which are widely applied in industrial process design, were used
to optimize DNA amplification finger-printing (DAF). Quadratic loss functions
that penalize deviations from prediction values and L9 (3(4)) and L18 (3(8))
orthogonal arrays revealed effects and interactions of amplification reaction
components and thermal cycling parameters. Analysis of variance (ANOVA)
decomposed the contribution of individual factors to the experimental response
(amplification yield and product number), while verification experiments
established that optimum conditions were predictable, verifiable and
reproducible. While several amplification components (primer, magnesium and
enzyme) conditioned the amplification reaction, annealing temperature and time
were the only important thermal cycling contributing factors. The Taguchi
strategy defined a robust and transportable amplification protocol based on high
annealing temperatures (typically 48 degrees C) and primer concentrations
(typically 8 microM), which can be applied to the fingerprinting of a wide range
of DNA templates of plant and fungal origin. The general strategy of robust
experimental design holds potential as an optimization tool for other methods in
molecular biology.
PMID- 9762447
TI - DNA nicks and increased sensitivity of DNA to fluorescence in situ end labeling
during functional spermiogenesis.
AB - Terminal transferase can be used to quantitate DNA strand breaks in situ by
labeling free 3'-hydroxyl ends with exogenous nucleotides. Endogenous nicks in
DNA temporally appear and disappear during functionally significant structural
rearrangements of chromatin. Fluorescence in situ end labeling of mouse and rat
testicular cells demonstrated that functional spermiogenesis is associated with
abundant DNA nicks that occur in elongating spermatids, most likely as a result
of nucleoprotein changes during terminal differentiation. Detectable DNA breaks
were not observed in round spermatids and epididymal sperm.
PMID- 9762448
TI - lambda RNA internal standards quantify sensitivity and amplification efficiency
of mammalian gene expression profiling.
AB - There is an increasing interest in being able to document simultaneous levels of
multiple mRNAs from limited amounts of mammalian tissue. The combination of
amplified antisense RNA (aRNA) and reverse Northern blot analysis is one
technology that allows the measurement of relative levels of multiple mRNAs.
However, potential problems exist with this approach, such as (i) unknown
amplification efficiencies and sensitivity of detection, (ii) an inherent 3' bias
of amplified products and (iii) cross-hybridization of homologous mRNAs with the
gene targets. Each of these potential problems was addressed experimentally by
the use of poly(A) RNA internal standards synthesized from lambda phage (lambda)
DNA. The results showed detection levels of as few as 10 copies of the poly(A)
RNA internal standards. The internal standards aid in the optimization of
reaction conditions and also reduce dependence on traditional "housekeeping"
genes whose mRNA levels might or might not change. The overall results of these
experiments highlight and extend the general usefulness of amplified antisense
aRNA and reverse Northern blot analysis to study mRNA expression profiles.
PMID- 9762446
TI - Selective propagation of retinal pericytes in mixed microvascular cell cultures
using L-leucine-methyl ester.
AB - Endothelial cell (EC) propagation has been simplified by developing cell-specific
selection criteria. Methods commonly used for selectively isolating EC include:
(i) differential sieving of disaggregated tissue, (ii) differential plating of
cells on extracellular matrices, (iii) lectin affinity isolation of cell
populations and (iv) fluorescence-activated cell sorting of cells labeled with a
carbocyanine dye of acetylated low-density lipoprotein (DiI-Ac-LDL). Few criteria
for selectively propagating pericytes (PC) are currently available. Nonspecific
esterases exhibit a high degree of multiplicity when compared with other
mammalian isozymes and may be suitable for the identification and selective
propagation of cells of the microvasculature. Evaluation of esterase isotype
expression in PC and EC by zymography indicates PC contain alpha-naphthyl acetate
and alpha-naphthyl butyrate hydrolyzing esterases as well as dipeptidyl peptidase
I, while EC only contain alpha-naphthyl acetate esterase. The cytotoxic response
of PC and EC to various amino acid esters is assessed by monitoring vital dye
uptake and by light microscopy. Several amino acid esters are cytotoxic to both
cell types, whereas 50 mM L-leucine methyl ester (L-Leu OMe) is toxic to EC but
not to PC. This amino acid ester is also toxic to mesothelial and retinal
pigmented epithelial cells, other common contaminants of PC cultures. Analysis of
protein composition by two-dimensional gel electrophoresis indicates that L-Leu
OMe does not stimulate expression of stress response proteins in PC. Thus, L-Leu
OMe can be utilized to cultivate PC selectively from mixed cell populations.
PMID- 9762449
TI - Mutation typing using electrophoresis and gel-immobilized Acrydite probes.
AB - A new electrophoresis technology for hybridization-based sequence detection and
mutation typing is described. Intrinsic to this approach is copolymerization of
specially modified oligonucleotide probes directly into polyacrylamide gels.
Electrophoresis of single-stranded samples through gels containing specific
immobilized probes results in hybridization-mediated capture of complementary
targets. By increasing gel temperature or including denaturants in the buffer,
the method can be used to type single-nucleotide polymorphisms. The method can
easily be adapted to type mutations in PCR-amplified samples. Acrydite gel
technology will also be useful for many other applications, including
hybridization-based diagnostics, analysis of gene expression and purification of
nucleic acids from biological samples.
PMID- 9762450
TI - Measurement of isolated myocyte volume using the Coulter models Z2 and ZM/C256: a
comparison of instrument function.
AB - Changes in cardiac structure that depart from normal have generally been termed
"remodeling". Assessment of ventricular remodeling at the cellular level should
include measurement of myocyte dimensions. A well-established and reliable method
to assess myocyte remodeling uses isolated cells and the Coulter
Counter/Channelyzer system. The new Coulter Model Z2 has numerous modifications
and improvements from the Model Z predecessor(s) interfaced to a pulse-height
analyzer (e.g., channelyzer). Improvements of the Model Z2 over older instruments
include: (i) elimination of the mercury manometer with accompanying oil
displacement pump; (ii) reduced size and weight; (iii) a higher degree of
mechanization and automation; (iv) inclusion of an advanced comprehensive
statistical package and (v) a substantial reduction in cost. The purpose of this
study was to determine if the newly modified instrument produces the same results
as the previous instrument combinations, which were shown to produce reliable
cell volume data from irregularly shaped cells such as cardiac myocytes.
PMID- 9762451
TI - Aetiology of oral cancer: alcohol.
AB - The effect of alcohol alone on the oral mucosa and its association with the
development of oral cancer is difficult to establish, principally because alcohol
consumption histories are difficult to verify, alter over time, both with respect
to beverage type and quantity, and are frequently confounded by tobacco use. This
review considers the various pathways by which alcohol may exert such an
influence. Namely, due to topical exposure (e.g. direct effect on cell membranes,
altered cell permeability, variation in enzymes that metabolise alcohol) and/or
systemic effects (e.g. nutritional deficiency, immunological deficiency,
disturbed liver function). Finally, the numerous papers that have sought to
establish the relative risk for oral cancer in association with alcohol intake
are reviewed.
PMID- 9762452
TI - Proliferative activity and loss of function of tumour suppressor genes as
'biomarkers' in diagnosis and prognosis of benign and preneoplastic oral lesions
and oral squamous cell carcinoma.
AB - Oral cancer is a disease of the elderly and is closely connected with cigarette
smoking and alcohol consumption. Since the successful introduction of
multidisciplinary treatment, the survival rate has not changed. Because of the
high mortality and potentially disfiguring treatment, today's efforts are aimed
at eliminating risk factors, chemoprophylaxis, improvement in diagnostic
procedures, and understanding of the genetic mechanisms of oral carcinogenesis.
Immunohistochemical and molecular biology analysis of biopsy tissue and cell
lines of preneoplastic and neoplastic lesions that originate from the oral mucosa
have shown that alterations in tumour suppressor genes such as p53 and Rb gene
may have an important role in oral carcinogenesis and may be potentially useful
prognostic 'biomarkers' in oral carcinogenesis. Statistical analysis of
immunohistochemical data from 216 patients did not identify significant or
consistent differences of p53, MDM2, or RB expression with respect to stage of
disease, malignant transformation, metastatic node involvement, recurrence, or
survival. Nevertheless, p53 overexpression seems to correlate strongly with
histological progression of the disease, which confirms the importance of p53
alterations in oral carcinogenesis. Overexpression of p53 is usually found in the
less differentiated proliferating cells in benign and malignant oral lesions.
Assessment of the proliferating activity is possible by immunohistochemical
staining with monoclonal antibodies against proliferating nuclear antigen and Ki
67. Statistical analysis shows that overexpression of p53 combined with high
proliferative activity predicts a less favourable course of disease in oral
squamous cell carcinoma.
PMID- 9762453
TI - Orthognathic surgery: the patients' perspective.
AB - It is often thought that patients seek combined orthodontic and surgical
treatment for predominantly aesthetic reasons, with functional concerns being
secondary. To find out whether patients were more satisfied with appearance than
function after treatment, all 165 patients who had orthognathic operations during
the 11-year period 1983-94 were sent a questionnaire; 139 responded (84%). Rating
on a visual analogue scale showed a high level of satisfaction for both
appearance (mean score 6.78) and function (mean score 7.24) (Wilcoxon test, P =
0.046). This indicates that orthognathic surgery is not merely done for aesthetic
reasons, but is important when combined with orthodontic treatment in correcting
severe malocclusions, which appreciably improve the ability to chew.
PMID- 9762454
TI - Fibrous dysplasia of the craniomaxillofacial region: current clinical
perspectives.
AB - Fibrous dysplasia is a benign fibro-osseous disease of bone of unknown etiology.
Its occurrence in the craniomaxillofacial skeleton is frequent and varies in
severity from an asymptomatic monostotic lesion to polyostotic involvement
resulting in progressive functional deficit and aesthetic problems. With the
advent of refined instrumentation and craniofacial surgical techniques, a more
aggressive, non-disabling approach to these benign yet deforming fibro-osseous
growths is possible. In some patients, complete excision of the involved bone
with graft reconstruction of the resultant defect with primary autogenous bone
may be possible. Lifelong continuous ongoing monitoring of the involved region is
required throughout the patient's life.
PMID- 9762455
TI - The use of computer-generated three-dimensional models in orbital reconstruction.
AB - In this paper we describe the application of three-dimensional (3D) imaging and
computer-generated models in the management of orbital deformity. The technique
was found to be particularly useful in posttraumatic deformity and fibrous
dysplasia involving the orbit. Further application was found in cases of
radiation hypoplasia, high facial cleft, and facial atrophy. Funding restrictions
necessitate appropriate selection of cases when using new and expensive 3D
imaging rather than traditional and less expensive methods. To remain within a
realistic budget only those patients who will clearly benefit from the third
dimension compared with traditional methods of assessment and management should
be selected. These include patients requiring precise reduction or secondary
reconstruction in which there is a matched normal anatomical component for
comparison. This application is also only beneficial where the planned
reconstruction is dimensionally stable.
PMID- 9762456
TI - Vascularity of the dental pulp after segmental osteotomy in the chacma baboon
(Papio ursinus).
AB - OBJECTIVE: To assess the vascularity of the dental pulp after segmental
operations with and without interpositional autogenous bone grafting. DESIGN:
Experimental study. SETTING: University Department, South Africa. ANIMALS: 26
chacma baboons. INTERVENTIONS: Maxillary and mandibular posterior segmental
osteotomies were perfused with barium sulphate 3, 6, 12 and 18 months
postoperatively. The animals were killed at 3, 6, 12 and 18 months after surgery
and perfused with barium sulphate. Barium-filled vessels were counted in
histological sections from 189 control and experimental teeth. MAIN OUTCOME
MEASURE: Number of blood vessels. RESULTS: Blood vessel counts in mandibular
teeth in osteotomy segments ranged from 0 to 1.15 compared with 2.27 to 4.58 in
control teeth, while in maxillary teeth counts ranged from 0.54 to 2.22 for
experimental teeth and 3.3 to 4.65 for controls. For both jaws, the numbers of
vessels in experimental teeth gradually increased between 3 and 18 months but
remained less than those in control teeth. Numbers of blood vessels were similar
in graft and no-graft groups but both were less than half the counts in control
teeth. CONCLUSION: Blood flow is present in the teeth at all times after
posterior segmental osteotomy but there is a risk of ischaemia.
PMID- 9762457
TI - Reconstruction of the extremely resorbed mandible with interposed bone grafts and
placement of endosseous implants. A preliminary report on outcome of treatment
and patients' satisfaction.
AB - During recent decades many surgical techniques have been developed to enlarge the
denture-bearing area of the mandible. Most of these techniques improved retention
and stability of the lower dentures only temporarily. Since the advent of
endosseous implants to stabilize overdentures, combinations of augmentation
procedures and placement of endosseous implants have been introduced to restore
the severely resorbed mandible. In this study we describe the preliminary results
of such a combined approach using sandwich osteotomy with an autogenous bone
graft (iliac crest) followed by placement of four endosseous implants in the
interforaminal region in 10 women. After a mean follow-up period of 31 months
(range 19-57) several variables were measured including condition of the peri
implant tissues, radiographic bone changes and patient satisfaction. The first
results indicate that the technique described offers a solid base for implant
stabilized overdentures: no implants were lost, the peri-implant tissues were in
good condition, bone loss was limited, and patients were satisfied. Future
studies will evaluate the permanence of these results.
PMID- 9762458
TI - Treatment of the edentulous mandible with a vestibuloplasty combined with
Intramobil Zylinder implants: a 5-year follow-up.
AB - The long-term success of endosseous implants is related to healthy peri-implant
tissues. Attached keratinized mucosa does not seem important for the prevention
of soft tissue complications. Prevention of muscle attachment near the implants,
however, seems more decisive for maintaining a favourable peri-implant
environment. We treated 150 patients from 1990-91 with two Intramobil Zylinder
implants and modified vestibuloplasty, 65 of whom were randomly selected for
evaluation at 1 year; 48 of the 65 were also seen at 5 years. The vestibuloplasty
was done by the technique of Pichler and Trauner, to prevent muscle pull and to
create a thin layer of mucosa around the implants, and endosseous osseointegrated
implants were inserted. The results show an adequately depended vestibulum with
no muscle pull around the implants and significantly lower pocket depth after 5
years of follow-up compared with similar studies.
PMID- 9762459
TI - Immunocytochemistry of fine-needle aspirates from central giant cell granuloma.
AB - Fine needle aspiration biopsy (FNAB) is an important technique in the diagnosis
of oral and maxillofacial conditions. We describe here the cytological and
immunocytological findings in four patients with central giant cell granuloma.
All the aspirates showed mononuclear cells associated with many giant cells. We
conclude that immunocytochemical examination of FNAB specimens helps to confirm
the provisional clinical diagnosis of central giant cell granuloma.
PMID- 9762460
TI - Diagnostic imaging in two cases of recurrent maxillary ameloblastoma: comparative
evaluation of plain radiographs, CT and MR images.
AB - We report detailed clinical and imaging findings of two patients with recurrent
maxillary ameloblastoma. In one patient the recurrent tumour presented at follow
up examination 5 years after the initial operation. The other patients had a far
advanced recurrent tumour with maxillary destruction extending into the adjacent
normal structures including the infratemporal fossa, infraorbital fissure,
masticator space and the left ethmoid sinus. The findings on conventional
radiography including panoramic, posteroanterior and Waters' projection, and the
findings of computed tomography (CT) and magnetic resonance (MR) imaging were
evaluated using the following three variables: artefact degradation, lesion
detectability, and conspicuity. The results suggested that MR imaging was the
best imaging method for visualization of the tumours, followed by contrast
enhanced CT. These two cases show that maxillary ameloblastoma can be difficult
to control when it extends to the adjacent normal structures after destroying the
maxilla. MR imaging was essential to establish the exact extent of the advanced
maxillary ameloblastoma.
PMID- 9762461
TI - Cutaneous sinus tract of dental origin--imaging with a dental CT software
programme.
PMID- 9762462
TI - Synovial chondromatosis of the temporomandibular joint.
PMID- 9762463
TI - Langerhans' cell histiocytosis.
PMID- 9762464
TI - Re: Pratt et al. Controversies in third molar surgery: the national view on
review strategy. Br J Oral Maxillofac Surg 1997; 35: 319-322.
PMID- 9762465
TI - Pathological fracture of the mandible treated with diphosphonates.
PMID- 9762466
TI - Microtubule depolymerization induces stress fibers, focal adhesions, and DNA
synthesis via the GTP-binding protein Rho.
AB - Microtubule depolymerization has multiple consequences that include actin stress
fiber and focal adhesion assembly, increased tyrosine phosphorylation and DNA
synthesis. Similar effects induced by serum, or agents such as lysophosphatidic
acid, have previously been shown to be mediated by the GTP-binding protein Rho.
We have investigated whether the effects of microtubule depolymerization are
similarly mediated by Rho and show that they are blocked by the specific Rho
inhibitor, C3 transferase. Because microtubule depolymerization induces these
effects in quiescent cells, in which Rho is largely inactive, we conclude that
microtubule depolymerization leads to activation of Rho. The activation of Rho in
response to microtubule depolymerization and the consequent stimulation of
contractility suggest a mechanism by which microtubules may regulate
microfilament function in various motile phenomena. These range from growth cone
extension to the development of the contractile ring during cytokinesis, in which
there are interactions between the microtubule and microfilament systems.
PMID- 9762467
TI - Localisation of a novel adhesion blocking epitope on the human beta 1 integrin
chain.
AB - Members of the beta 1 integrin family mediate cellular adherence to a wide range
of extracellular and cell surface associated ligands. Conformational changes have
been shown to be associated with integrin activation and ligand binding. Some
studies suggest that there may be a restricted region of the beta 1 integrin that
serves as the target for regulatory antibodies which can inhibit or stimulate
integrin function. Here we identify an inhibitory epitope that is located at a
distinct sight from that suggested for other inhibitory antibodies. Three
different adhesion blocking antibodies, JB1A, C30B, and D11B bind to a peptide
corresponding to residues 82-87 of the mature beta 1 chain. Mn++ inhibited the
binding of JB1A to purified beta 1 integrin. In contrast the binding of several
other antibodies to beta 1 were not influenced by these conditions. JB1A binding
to purified peptide was also inhibited by Mn++ suggesting that it related to
interference with the antibody function rather than a cation dependent change in
the epitope. Our data 1) directly demonstrates the peptide sequence recognised by
three adhesion blocking antibodies to the human beta 1 integrin chain 2)
identifies a novel epitope located at residues 82-87, distinct from that of
previously described regulatory epitopes 3) characterises a Mn++ sensitive
antibody integrin interaction. Collectively, these results indicate the existence
of multiple regulatory sites on the beta 1 integrin molecule.
PMID- 9762468
TI - Binding of the alpha 2 integrin I domain to extracellular matrix ligands:
structural and mechanistic differences between collagen and laminin binding.
AB - The alpha 2 beta 1 integrin functions as a cell surface receptor for collagen on
some cells and as both a collagen and laminin receptor on a more restricted
subset of cell types including endothelial and epithelial cells. The alpha 2
integrin subunit I domain binds collagen in a divalent cation-dependent manner.
In contrast, I domain binding to laminin occurs via both divalent cation
dependent and -independent mechanisms. Saturable binding was observed in the
presence of either Mn2+ or EDTA, although the extent of binding in Mn2+ was twice
that observed in EDTA. Half-maximal binding occurred at about 22 nM I domain in
either case. Whereas laminin binding was significantly enhanced by Mn2+, with
half-maximal binding occurring at 1.9 mM Mn2+, Mg2+ was much less effective.
Deletion of the N-terminal 35 residues of the I domain, including the DXSXS
portion of the MIDAS motif, caused a significant diminution of laminin binding
activity. Laminin binding by the I domain was significantly inhibited by the
alpha 2 beta 1 function-blocking antibody 6F1 in the presence of either EDTA or
Mn2+. The non-function-blocking antibody 12F1 had no effect. In contrast to the
binding of the alpha 2 integrin I domain to collagen, the laminin binding
activity of the I domain was not enhanced by the addition of the first EF hand
motif of the integrin.
PMID- 9762469
TI - A mutation in alpha-catenin disrupts adhesion in clone A cells without perturbing
its actin and beta-catenin binding activity.
AB - Cadherin mediated cell-cell adhesion requires cytoplasmic connections to the
cytoskeleton mediated by alpha-catenin. Original descriptions of the catenins, as
well as our own in vitro studies, have suggested that this connection was
mediated by the interaction of alpha-catenin to actin. Loss of adhesion in the
human colon carcinoma cell line "Clone A" is the result of an internal deletion
mutation of 158 residues near the N-terminus of the protein resulting in an 80 kD
mutated protein. Transfection of these cells with the full length protein
restores the normal adhesive phenotype. We have characterized this mutant protein
in efforts to understand the normal function of alpha-catenin and, in particular,
the region deleted in the Clone A mutant. Co-precipitation experiments using
whole cell lysates indicate that the mutant form of alpha-catenin binds beta
catenin and plakoglobin, and can form a structural complex with E-cadherin via
these interactions. Actin co-sedimentation assays show that the recombinant
mutant binds and bundles F-actin and binds both actin and beta-catenin
simultaneously, as seen with wild type alpha-catenin. These results suggest that
the stabilization of the E-cadherin-catenin complex may be mediated by factors
beyond its direct interaction with actin. We conclude that a region near the N
terminus of alpha-catenin mediates additional interactions between the adhesive
complex and the cytoskeleton that are critical for functional adhesion.
PMID- 9762470
TI - Protein phosphatase 1 delta is associated with focal adhesions.
AB - In all mammalian cells protein phosphatase-1 (PP1) exists in three isoforms,
defined as alpha, gamma 1 and delta. Immunofluorescence studies with isoform
specific antibodies indicated that delta, but not alpha or gamma 1, is enriched
at focal adhesions in HeLa cells, fibroblasts, endothelial cells and
keratinocytes. This was confirmed also by interference reflection microscopy,
which indicated that PP1 delta was in areas of tight adhesion of the membrane to
the extracellular matrix at sites where the microfilament cytoskeleton is
organized. In all the cell types so far considered the PP1 delta in focal
adhesions represented only a small aliquot of the total PP1 delta, which was
predominantly localized to the nucleus. The association of PP1 delta to focal
adhesions was confirmed by the co-immunoprecipitation of PP1 delta with the focal
adhesion kinase pp125FAK and with the alpha v integrin. Comparison between the
amount of PP1 delta associated with focal adhesion proteins and that of PP1 delta
recovered in an anti-PP1 delta immunoprecipitate confirmed that only a minor
amount of the enzyme was associated with the focal adhesions. Since some focal
adhesion proteins are phosphorylated on Ser/Thr, it is likely that PP1 delta may
be involved in the regulation of focal adhesion functions and particularly in the
signaling pathway generated by cell-substratum adhesion.
PMID- 9762471
TI - Adhesive interactions of human multiple myeloma cell lines with different
extracellular matrix molecules.
AB - Multiple myeloma represents a human B cell malignancy which is characterized by a
predominant localization of the malignant cell clone within the bone marrow. With
the exception of the terminal stage of the disease the myeloma tumor cells do not
circulate in the peripheral blood. The bone marrow microenvironment is believed
to play an important role in homing, proliferation and terminal differentiation
of myeloma cells. Here we have studied the expression of several extracellular
matrix (ECM) molecules in the bone marrow of multiple myeloma patients and
analyzed their adhesive capacities with four different human myeloma-derived cell
lines. All ECM molecules analyzed (tenascin, laminin, fibronectin, collagen types
I, III, V and VI) could be detected in bone marrow cryostat sections of multiple
myeloma patients. Adhesion assays showed that only laminin, the microfibrillar
collagen type VI and fibronectin were strong adhesive components for the myeloma
cell lines U266, IM-9, OPM-2 and NCI-H929. Tenascin and collagen type I were only
weak adhesive substrates for these myeloma cells. Adhesion to laminin and
fibronectin was beta 1-integrin-mediated since addition of anti-beta 1-integrin
antibodies could inhibit the binding of the four different cell types to both
matrix molecules. In contrast, integrins do not seem to be involved in binding of
the myeloma cells to collagen type VI. Instead, inhibition of binding by heparin
suggested that membrane-bound heparan sulfate proteoglycans are responsible
ligands for binding to collagen type VI. Adhesion assays with several B-cell
lines resembling earlier differentiation stages revealed only weak interactions
with tenascin and no interactions with collagen type VI, laminin or fibronectin.
In summary, the interactions of human myeloma cells with the extracellular matrix
may explain the specific retention of the plasma cells within the bone marrow.
PMID- 9762472
TI - Expression profile of vascular cell adhesion molecule-1 (CD106) in inflammatory
foci using rhenium-188 labelled monoclonal antibody in mice.
AB - Rhenium (Re)-188 is a generator (W-188/Re-188) produced high energy beta-emitter
suitable for radionuclide therapy (T1/2 is 16.9 hrs and Emax 2.1 MeV (range 11
mm)). We have labelled monoclonal antibody (MAb) raised against vascular cell
adhesion molecule-1 (VCAM-1) with Re-188 using glucoheptonate chelation technique
and SnCl2 as reducing agent. The labelling efficiency, free perrhenate and
reduced Re were controlled with thin layer chromatography and the purification of
Re-188-MoAbs was performed using gel filtration. Our results indicate that Re-188
labelled antibodies remain in vitro stable and the labelling purity is > 90%. We
also have applied these Re-188-MoAbs for detection of inflammatory disease in a
mouse. The effective half-lives of organs of interest after an injection of Re
188-anti-VCAM1 were as follows: blood 5.2 hr, kidney 4.7 hr, and liver 9.6 hr. Re
188-anti-VCAM-1 was found to accumulate mainly in kidney and liver. One hour
after the injection, the kidney contained in average as high as 12.5% and the
liver 2.8 ID/g tissue. After 6 hr, the kidney contained 5.5% ID/g and the liver
2.6% ID/g. At 24 hr, the kidney uptake was 0.5% ID/g and the liver uptake 0.8%
ID/g, respectively. The inflamed foci, subcutaneous lesions in the footpad skin,
were visualized using gamma camera. From the distribution data the uptakes in the
inflamed foci as follows: at 1 hr 2.18 (inflammation) and 1.72% ID/g (control),
at 6 hr 1.42 (inflammation) and 0.85% ID/g (control), and at 24 hr 0.17
(inflammation) and 0.084% ID/g (control), respectively. Anti-VCAM-1 MAb showed
better targeting as compared to control MoAbs in inflammation (caused by E.coli
lipoplysaccaride). In conclusion, Re-188 is suitable for MAb labelling, and MAb
against VCAM-1 may be used for detection of local inflammatory disease.
PMID- 9762473
TI - Tendinopathy: an Achilles' heel for athletes and clinicians.
PMID- 9762474
TI - Long-term restoration of deficits in bone mineral density is inadequate in
premenopausal women with prior menstrual irregularity.
AB - OBJECTIVE: To investigate change in bone mineral density (BMD) in premenopausal
women (age, 29-46 years), some of whom were marathon runners with a history of
menstrual irregularity. DESIGN: Longitudinal follow-up. SETTING: University
medical school. PARTICIPANTS: We investigated 8 sedentary controls (SC) and 19
marathon runners (12 with regular menses (R) and 7 with a history of irregularity
(OA) 11.7 +/- 7.9 years before follow-up). MAIN OUTCOME MEASURES: BMD (g/cm2) of
lumbar spine (LS) and proximal femur were determined at baseline and follow-up (3
5 years later). We calculated a menstrual history index (MHI) (estimated
periods/year since age 13). RESULTS: Body mass, age at menarche, and femoral BMD
were not statistically different. Follow-up LS BMD (g/cm2) was lower (p < 0.01)
in OA (0.936 +/- 0.060) than in R (1.043 +/- 0.103) and SC (1.094 +/- 0.077),
even when covarying for age or both age and mass. No group changed BMD
significantly with time. Current MHI was lower (p < 0.001) in OA (9.7 +/- 1.4)
than in R (11.3 +/- 0.5) and SC (11.8 +/- 0.4). MHI for the teenage years was
lower in OA than in SC but not in R. OA had significantly lower MHI than did R
and SC for the third and fourth decades. Only MHI during the third decade
correlated significantly with LS BMD for all subjects. CONCLUSIONS: Restoration
of LS BMD deficit in women with prior menstrual irregularity aged over 30 is slow
and may never reach the same level as age-related controls; secondly, this may be
the result of both bone loss in the third decade of life and reduced acquisition
during adolescence.
PMID- 9762475
TI - Development, implementation, and validation of the Canadian Intercollegiate Sport
Injury Registry.
AB - PURPOSE: To outline the development and implementation of the Canadian
Intercollegiate Sport Injury Registry (CISIR), to examine its validity, including
the data collection forms, the recording of athlete exposure, and the mechanism
of injury, and to determine the ability of the CISIR to meet its stated
objectives of assessing rates and risk of injury. DESIGN: Prospective cohort
study. SETTING: Canadian intercollegiate athletics. SUBJECTS: 344 varsity
football players from five western Canadian universities. ASSESSMENT OF RISK
FACTORS AND OUTCOME MEASURES: Three data collection instruments were developed to
capture the principle types of information forming the cornerstones of the CISIR:
a medical form for preseason assessment of risk factors, a weekly exposure sheet
(WES) for the documentation of daily individual athlete participation, and an
individual injury report form (IIRF) for collection of injury-related
information. Design and implementation input was provided by therapists and
physicians through initial meetings, pilot testing, site visits, questionnaire,
and final consensus meeting. The completeness of injury reporting was assessed
through cross-referencing with participation time loss data. An item analysis was
conducted on the principal elements of the IIRF. The categorization of
participation itself was also examined, as was the diagnostic agreement between
the therapists and physicians involved in data collection. The recorded mechanism
of injury was compared with that noted through a video analysis for game-related
injuries. Lastly, a test analysis was conducted to extract data and compute rates
and risks of injury. RESULTS: This developmental phase was successful, with 99.7%
subject enrollment, high therapist satisfaction, and good flow of data. A
relational database, incorporating dual-entry data verification, was designed and
functioned well. The collection process revealed that 100% of the WESs were
submitted, and the data therein was 99.7% complete. The injuries resulting in
participation time loss were recorded on an IIRF 97.9% of the time. The exposure
(participation) codes were thought to be overly precise, and a simplification of
these categories is suggested. The diagnostic agreement between physicians and
therapists was 70%. It was possible to validate game exposures, but no standard
was identified to permit validation of the categories of exposure. Likewise, the
mechanism of injury as recorded by the therapists was thought to be more precise
than the video analysis. After two modifications in the table structure of the
relational database, it was possible to extract data relating to rates and risks
of injury. CONCLUSIONS: This study demonstrated a high degree of validity for
many elements of the CISIR. One limitation was that no reference standard existed
for some components, limiting some aspects of validity assessment. With the
suggested revisions, the CISIR represents the current standard in athletic injury
reporting in terms of individual injury risk assessment. This system will be used
in the future to explore the prediction and prevention of sport injuries.
PMID- 9762476
TI - Hormonal responses to endurance training and overtraining in female athletes.
AB - OBJECTIVE: To examine different hormonal responses to heavy endurance training
and overtraining in female athletes. DESIGN: Submaximal and maximal treadmill
tests, self-report mood measures, and stress hormone analyses were repeated at
baseline, after 4 weeks and at the end of 6 to 9 weeks of experimental intensive
training and after 4 to 6 weeks of recovery. SUBJECTS: Fifteen healthy female
endurance athletes increased their intensive training volume by 130% and base
training volume by 100% (ETG, n = 9) or served as controls (CG, n = 6). MAIN
OUTCOME MEASURES: Maximal oxygen uptake (VO2max), mood dynamics, blood
catecholamines, cortisol and testosterone at rest and after submaximal and
maximal exercise, and nocturnal urine catecholamines. RESULTS: Five females from
the ETG demonstrated an over-training state (OA subgroup) at the end of the
training period. Their VO2max decreased (mean +/- SEM) from 53.0 +/- 2.2 ml.kg
1.min-1 (range, 46.8-59.2) to 50.2 +/- 2.3 ml.kg-1.min-1 (range, 43.8-56.6) (p <
0.01). Maximal treadmill performance expressed as oxygen demand decreased (mean
+/- SEM) from 56.0 +/- 1.6 ml.kg-1.min-1 (range, 51.5-60.5) to 52.2 +/- 1.1 ml kg
1.min-1 (range, 49.1-55.3) (p < 0.01). Maximal heart rate also decreased (mean +/
SEM) from 190 +/- 1 bpm (range, 185-197) to 186 +/- 2 bpm (range, 184-193) (p <
0.05), and the athletes experienced mood disturbances. Plasma adrenaline levels
at maximal and noradrenaline at submaximal work rate decreased during the last 2
to 5 training weeks (p < 0.05), and serum cortisol levels at maximal work rate
decreased during the first 4 training weeks (p < 0.05) in the ETG. Plasma
adrenaline at maximal work rate decreased during the first 4 training weeks (p <
0.05) in the OA subgroup. There were no changes in the CG. Individual hormonal
response types to heavy training and overtraining were found. CONCLUSIONS:
Hormone responses to exercise load are superior in indicating heavy training
induced stress when compared with resting hormone levels. These responses
indicated decreased sympathoadrenal and/or adrenocortical activity (or exhaustion
of the adrenal gland or the central nervous system). Individual hormonal profiles
are needed to follow up training effects. Marked individual differences were
found in training- and overtraining-induced hormonal changes.
PMID- 9762477
TI - Injuries in runners: a prospective study of alignment.
AB - OBJECTIVE: To determine if measurable lower extremity alignment is a risk factor
for overuse running injuries. DESIGN: Prospective cohort study. SETTING: Thirty
two week marathon training program. PATIENTS OR PARTICIPANTS: Three hundred fifty
five volunteers from the marathon training program began the study; 255 finished
the study. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Past training and injury
history was determined by questionnaire, and five lower extremity alignment
measures were performed at the beginning of the training program: arch index
(AI), heel valgus (HV), knee tubercle-sulcus angle (TSA), knee varus (KV), and
leg-length difference (LLD). Overuse injuries, incurred by the runners and
categorized by anatomic parts, were recorded during the training period. RESULTS:
Ninety subjects experienced overuse injuries. Multivariate analyses with stepwise
Poisson regression showed few consistent relationships between alignment and
overuse injury rates. Higher AI was protective against overall injuries and knee
injuries; higher HV was protective against knee and foot injuries; higher TSA was
associated with shin injuries; higher KV was associated with shin injuries; and
low LLD was associated with more overall injuries. CONCLUSIONS: Minor variations
in lower extremity alignment do not appear conclusively to be major risk factors
for overuse injuries in runners. Because of the study limitations and the likely
multifactorial nature of running injuries, further study is suggested, perhaps in
more novice runners.
PMID- 9762478
TI - Discordant public perception of doping in elite versus recreational sport in
Switzerland.
AB - OBJECTIVE: To assess public awareness of performance-enhancing drug use, that is,
doping in sport in Switzerland. DESIGN: Representative telephone survey in
September 1995. SETTING: Two of the three Swiss linguistic areas (French and
German), representing 96% of the entire Swiss population. SUBJECTS: A total of
1201 respondents between 18 to 74 years old, selected by stratified random
sampling. MAIN OUTCOME MEASURES: Perception of the doping problem in elite versus
recreational sport, estimated prevalence of doping in different sports, parents'
decisions to keep children out of sport because of doping. RESULTS: The use of
doping in sport was perceived as a "somewhat serious problem" or "very serious
problem" by 84% of the respondents for elite sport and by 44% for recreational
sport (p < 0.01 for difference). Doping was mostly perceived to represent a
physical health problem or an ethical problem. Track and field (79%) and cycling
(27%) were most often cited as sports having doping problems, and 35% of the
respondents believed that > 60% of bodybuilders use doping. The black market
(91%), athletes and trainers (80%), and fitness centers (74%) were the most
frequently mentioned sources of doping substances. Thirteen of 14 parents would
not dissuade their children from participating in sport because of a concern
about the problems of doping. CONCLUSIONS: The Swiss population perceives a high
prevalence of doping in sports. There is a clear distinction, however, made by
the respondents between the estimated prevalence of doping in elite sport, seen
overwhelmingly as a "very serious problem" or "somewhat serious problem," and
recreational sport, in which doping is less often seen as a problem. Doping is
considered a serious threat to health and ethics in sport, but despite this
judgment, only a few parents would hold back their children from sport because of
the risks of doping.
PMID- 9762479
TI - Two measures of physical activity as predictors of bone mass in a young cohort.
AB - OBJECTIVE: To compare the association of two measures of physical activity with
bone mass in healthy children and young adults, as part of a larger study on bone
mineral acquisition in youth. DESIGN: Cross-sectional observation study. SETTING:
General community, outpatient study. PARTICIPANTS: Subjects included 103 non
Hispanic white female (n = 54) and male (n = 49) healthy volunteers aged 9 to 25
years. MAIN OUTCOME MEASURES: Self-reported physical activity was measured by a 3
day activity diary of all activities and a questionnaire designed to capture
recreational activities throughout the year. Activity was expressed as hours per
week of weight-bearing and non-weight-bearing activity. Bone mass at the hip,
spine, and whole body was measured by dual x-ray absorptiometry. RESULTS: The
activity measures were not well correlated with each other. In males, weight
bearing and non-weight-bearing activity reported in 3-day diaries was positively
associated with bone mass at the hip, spine, and whole body (p < 0.05). Among
females, only weight-bearing activity measured by the yearly questionnaires was
significantly positively associated with bone mass (p < 0.05). In males and
females, weight-bearing activity was more highly correlated with bone mineral
than was non-weight-bearing activity. In addition, the associations between
activity and bone mass varied by skeletal site. CONCLUSIONS: The association
between physical activity and bone mass varied both in direction and in
significance depending on the physical activity instrument used. Gender
differences were observed in the associations between specific activity
instruments, type of activity (weight-bearing and non-weight-bearing), and bone
mass at different skeletal sites. Variability associated with the two physical
activity measures may contribute to discrepant findings in this study and in the
literature.
PMID- 9762480
TI - Prospective evaluation of history and physical examination: variables to
determine radiography in acute ankle injuries.
AB - OBJECTIVE: This study investigated history and physical findings among 74
patients with acute ankle injuries in order to determine factors significantly
associated with fractures, excluding avulsion fragments < 3 mm in size, and
syndesmosis injuries and to determine factors that necessitate radiography.
DESIGN: This was a prospective study performed during a 12-month period. After
recording history and physical examination data, a gestalt prediction of a
positive or negative radiographic result was made before the patient underwent
ankle radiography. Analysis then determined factors important for radiography.
PATIENTS AND SETTING: Patients who presented to a sports medicine center with an
acute ankle injury were enrolled in the study after meeting the enrollment
criteria. MAIN OUTCOME MEASURES: Before analysis, predictions for injury were
based on accepted indicators. Outcome measures, factors that would indicate the
need for radiography, were formulated after data collection and statistical
analysis. RESULTS: Radiographic findings showed nine fractures and three widened
syndesmoses as well as 15 minor ligamentous avulsions. Statistical analysis
showed significant association (p < 0.05) of fracture with previous ankle
fracture, syndesmosis pain with external rotation stress testing, and pain along
the middle third of the distal fibula, from anterior to posterior. Syndesmosis
injuries had a significant association with pain during external rotation stress
testing. CONCLUSIONS: Although additional investigation with larger patient
numbers would be beneficial, this study highlights the importance of history of
previous fracture, pain on the distal mid-fibula or mid-tibia, and pain with
external rotation. Furthermore, if these three variables are prospectively
applied as criteria for radiography, a 55% reduction in radiography would result
with 100% sensitivity. Finally, experienced sports medicine physicians had a 100%
sensitivity, 68% specificity, 100% negative predictive value, and 39% positive
predictive value for prediction of clinically significant fractures or
syndesmosis injuries.
PMID- 9762481
TI - Electromyographic investigation of stretching: the effect of warm-up.
AB - OBJECTIVE: To compare the fine wire electromyographic (EMG) firing patterns
during static stretches in the biceps femoris, soleus, and gastrocnemius before
and after warm-up as well as over time. DESIGN: Experimental single group pretest
posttest design. SETTING: Biomechanics research laboratory. PARTICIPANTS: Sixteen
healthy volunteers 23 to 36 years of age with no history of lower extremity
injury. INTERVENTION: Subjects performed one hamstring stretch and four calf
stretches for 90 seconds, bicycled for 30 minutes as a warm-up, and stretched
again. MAIN OUTCOME MEASURE: EMG was recorded at time 0, 30, 60, and 90 seconds
during the stretches before and after warm-up. Recorded values were normalized to
EMG during maximum manual muscle testing (MMT). A two-way analysis of variance
with repeated measures (p < 0.05) was done to compare EMG activity during
stretching before and after warm-up as well as over time. RESULTS: Low EMG
activity was seen for all muscles (< 20% MMT). It was constant over the time of
the stretch for all muscles, but it increased in the soleus during the bent knee
stretch position. There was a statistically significant decrease in the EMG
activity after the warm-up for the gastrocnemius using the traditional and heel
off stretching positions and for the soleus using the heel off stretching
position (p < 0.05). The biceps femoris EMG activity showed no significant
differences before and after warm-up. CONCLUSIONS: EMG activity during static
stretching was low. Overall, the EMG activity remained constant with time for a
given stretch position. EMG of the soleus and gastrocnemius was significantly
less after warm-up for some stretches, whereas the EMG activity of biceps femoris
showed no differences before and after warm-up.
PMID- 9762482
TI - The effect of a needle biopsy of the vastus lateralis on isokinetic muscular
performance.
AB - OBJECTIVE: To determine the acute effects of a needle muscle biopsy of the vastus
lateralis on knee extension and flexion strength and endurance. DESIGN: Pretest
posttest design. Testing order of right or left leg was randomly determined.
SETTING: Research Laboratory, University of Alberta, Edmonton Alberta, Canada.
PARTICIPANTS: The subjects were 8 female and 11 male volunteers who were
recreationally active. The mean age, height, and weight were 23 +/- 5 years,
174.6 +/- 9.2 cm, and 73.5 +/- 7.3 kg, respectively. INTERVENTION: Isokinetic
testing for knee extension and flexion was performed on both legs before and
after a biopsy of the right vastus lateralis muscle. MAIN OUTCOME MEASURES: Knee
extension and flexion peak torque measured at an angular velocity of 1.05 rad.s
1. Mean torque during 25 consecutive maximal contractions at 3.14 rad.s-1 for
knee extension and flexion exercise. RESULTS: There was a significant decrease in
right knee extension peak torque after the biopsy of the vastus lateralis muscle.
No other differences were noted. CONCLUSIONS: These findings demonstrated an
acute inhibition of knee extension peak torque but not endurance because of a
muscle biopsy of the involved musculature.
PMID- 9762484
TI - Treatment of spondylolysis with external electrical stimulation and bracing in
adolescent athletes: a report of two cases.
PMID- 9762483
TI - How effective is exercise training for the treatment of hypertension?
AB - OBJECTIVE: Exercise is often recommended as therapy for hypertension, yet its use
is not widespread among clinicians. Reasons include uncertainty regarding its
efficacy, the relative importance of the exercise prescription determinants
(intensity and frequency), or confounding variables including patient
characteristics such as age and gender. This review will present the evidence for
exercise as a treatment for hypertension using a search of the English language
literature from January 1966 to January 1998. DATA SOURCES: A search of MEDLINE
articles using the MESH headings and textwords of blood pressure, hypertension,
exercise, and exertion as well as hand searches in related articles and cross
referencing. DATA EXTRACTION AND SYNTHESIS: Identified articles were reviewed for
their design characteristics, and specific attention was made of the subject
characteristics, the exercise training protocol, the magnitude of the blood
pressure-lowering response, and the influence of pharmacologic treatment on blood
pressure lowering. RESULTS: A total of 39 studies representing random and
nonrandom designs using predominantly walking-jogging exercise were identified.
These studies showed reductions in blood pressure (systolic blood
pressure/diastolic blood pressure) of -13/ -18 mm Hg in hypertensive patients.
Most of the antihypertensive effect of exercise training was observed after 10
weeks, whereas training more than three times per week or for more than 50
minutes did not confer added benefit. Lower intensity exercise resulted in
greater blood pressure reduction than did high intensity exercise. No gender
differences in the antihypertensive effect of exercise were observed although
most studies were performed in men. Although few studies were performed in older
patients, there did not appear to be an age-dependent antihypertensive effect of
exercise. There was a paucity of literature regarding the interaction of
pharmacologic therapy and exercise in hypertensive patients. CONCLUSIONS: The
results support the use of exercise as an effective therapy in hypertension.
Studies were generally lacking in adequate control groups. Future research
opportunities are many and should include studies using ambulatory monitoring and
stratification of patients with different degrees of hypertension, undergoing
different pharmacologic regimens.
PMID- 9762485
TI - Arachnoid cyst and subdural hygroma in a high school football player.
PMID- 9762486
TI - Atlantoaxial dislocation in a sumo wrestler.
PMID- 9762487
TI - Anomalous first rib in a high school wrestler.
AB - A combination of noninvasive treatment modalities applied with basic
biomechanical principles of motion was successful in treating an athlete with
rare underlying skeletal anomalies. Back strains with recurrence or atypical
findings require further workup. With such cervical rib anomalies, an athlete
needs to be examined for thoracic outlet syndrome.
PMID- 9762488
TI - Aminoglycoside ear drop ototoxicity: a topical dilemma?
PMID- 9762489
TI - Frey's syndrome and parotid surgery.
PMID- 9762490
TI - The treatment of hypertonicity of the pharyngo-oesophageal segment after
laryngectomy.
PMID- 9762491
TI - Suction diathermy adenoidectomy.
AB - This technique uses a combination of monopolar diathermy and suction to perform a
controlled resection of the adenoids in a near bloodless field. A clear view of
the entire resection is obtained with a mirror. There is minimal blood loss and
postoperative haemorrhage rate is extremely low. The authors describe the
technique used and discuss their experience.
PMID- 9762492
TI - The effectiveness of voice therapy for patients with non-organic dysphonia.
AB - Forty-five patients diagnosed as having non-organic dysphonia were assigned in
rotation to one of three groups. Patients in one group received no treatment and
acted as a control group. Patients in the other two groups received a programme
of either 'indirect' therapy or 'direct with indirect' therapy, respectively. A
self-report questionnaire of vocal performance, observed ratings of voice
quality, and computer-derived acoustic measurements (signal-to-noise ratio, pitch
perturbation and amplitude perturbation) were carried out on all patients before
and after treatment to evaluate the changes in voice quality over time. There was
a significant difference between the three groups on the self-report
questionnaire, voice quality ratings and pitch perturbation measurements (P = <
0.05). Thirteen out of 15 control patients showed no significant change on any of
the measures. Seven patients who received indirect treatment showed significant
improvement in voice quality following treatment. Fourteen out of 15 patients who
received direct treatment showed significant improvement in voice quality.
PMID- 9762493
TI - Improved survival in patients with head and neck cancer in the 1990s.
AB - It is generally felt amongst the medical profession and the lay public that
cancer is being treated more successfully than in the past. This is certainly
true for childhood malignancies and leukaemia but evidence that significantly
improved survival is occurring in the common solid tumours is lacking. Since 1963
the University of Liverpool Department of Otolaryngology/Head and Neck Surgery
has collected data on all patients with head and neck tumours presenting to the
department. The present study investigates patients with histologically proven
squamous cell carcinoma of the four main sites: larynx, hypopharynx, oral cavity
and oropharynx. From 1963 until the end of 1989, 2738 patients were seen by the
department and from 1990 a further 717 patients have been seen. Since 1990
patients have tended to be in better general physical condition but, on the other
hand, have tended to have more advanced disease at the primary site. The
department has latterly tended to see fewer laryngeal cancers and more cancers of
the oropharynx. Significantly fewer patients have presented with neck node
metastases. Multiple logistic regression suggests that the most significant
difference between the two groups is the great reduction in neck node recurrence
rates in the group of patients seen since 1990 (P = 0.0001). The recurrence of
tumours at the primary site since 1990 has been 35% compared with 41% before
1990, and recurrence in the neck nodes since 1990 has been 12%, compared with 15%
before 1990. These differences are significant (P = 0.0141 and P = 0.0494,
respectively). When studying survival in the 1960s, 1970s and 1980s, the 5-year
cure rate was 50%, whereas since 1990 the figure has risen to 60% tumour-specific
5-year survival--a significant difference. A similar effect was noted in observed
survival. This improvement in cure rate occurred for all four main sites. The
results were confirmed by Cox's proportional hazards model where year of
treatment was highly significantly associated with improved survival (P =
0.0001). It has been demonstrated that locoregional recurrence has improved since
1990 and this is reflected in improved survival figures. Although there are
differences in the parameters of tumours referred before 1990 and since 1990,
multivariate analysis suggests that the improvement in neck node recurrence rates
may be responsible for this improved survival rate. Multivariate analysis for
survival also suggests that the improvement in cure rates is independent of
compounding variables and dependent on the year of presentation of the tumour.
This improved survival may be related to factors, such as the administration of
radical postoperative radiotherapy.
PMID- 9762495
TI - The contemporary practice of functional endoscopic sinus surgery: a nationwide
survey.
AB - Recent years have seen a rapid growth in the practice of functional endoscopic
sinus surgery (FESS). Its introduction into clinical practice has, however, been
conspicuous by an absence of good scientific evidence that it is superior to
previous techniques. This postal questionnaire survey aimed to identify the
diversity in the practice of FESS at a national level and, as a result,
highlights areas of patient management requiring standardization. All full
members of the British Association of Otolaryngologists--Head and Neck Surgeons
(BAO-HNS) were contacted, 64% responded: 14% of surgeons do not always perform
preoperative computerized tomography (CT) scanning; only 25% use grading systems
for symptoms and/or CT assessment; a wide variety of topical agents are used both
before and after operation; nearly half (47%) no longer operate principally under
endoscopic vision but via TV monitors; and the majority of surgeons review
patients more than 1 week after surgery with a minority advocating earlier
postoperative assessment.
PMID- 9762494
TI - The prevalence of exostoses in the external auditory meatus of surfers.
AB - Fifty-four surfers and 38 surf life savers were examined and questioned in order
to determine the prevalence of exostoses. Seventy-three per cent had evidence of
body exostoses in the external auditory meatus. Forty per cent had their ear
canals narrowed by 50% or more. The relationship between the number of years
spent surfing or life saving and the extent of canal stenosis was highly
significant (P < 0.00001). Left and right ears were affected equally in this
series and the obstruction appears to begin after approximately 7 years and is
further aggravated by continued surfing. Over 90% of subjects who had
participated for longer than 10 years had some evidence of exostoses. There was
no significant association between the number of days per year or the number of
hours per day spent surfing and the development of surfer's ear in this sample.
Those who participated in their water sport over winter had significantly more
exostoses than those who did not (P < 0.0001). Those who lived in the South
Island (colder water) had more surfer's ear than those in the North Island
(warmer water).
PMID- 9762496
TI - Structured assessment of the consequences of composite resection.
AB - A structured quality of life questionnaire was developed as an instrument for the
assessment of the functional, physical, psychosocial, and counselling problems in
patients treated surgically for an oropharyngeal cancer. The questionnaire was
tested in a pilot study in a relatively homogeneous group of 15 selected patients
(all of whom had a comparable surgical defect, i.e. a composite resection of the
oropharynx and neck, and had undergone an identical reconstruction method, i.e. a
pedicled pectoralis major myocutaneous flap). All but two patients were
irradiated as well. A high reliability (Crombach's alpha) was found in most of
the applied subscales, indicating good internal consistency of the different
questions. Significant correlations were found between several quality of life
dimensions. The most frequently reported complaints concerned problems related to
eating, speaking, and facial disfigurement. Problems with mastication, oral
transport, and swallowing prohibited 11 patients returning to their normal diet.
Regarding speech, 11 patients reported decreased intelligibility, in eight this
was due to some degree of rhinolalia aperta. A significant association was found
between moderate intelligibility and anxiety about speaking in public (P < 0.05).
Eleven patients felt that the surgery had caused considerable facial
disfigurement. For five of them this had a negative influence on their social
interactions and activities outdoors. Thus, the consequences of the surgical
treatment of oropharyngeal cancer can be assessed in a systematic and formal way
with this specially designed structured questionnaire. Despite the small sample
size, the selection of a homogeneous patient group appeared to give significant
information, and to establish meaningful correlations.
PMID- 9762497
TI - Matrix metalloproteinase-2 and matrix metalloproteinase-9 in cholesteatoma and
deep meatal skin.
AB - A qualitative and quantitative study of the presence of Matrix metalloproteinase
2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9) in cholesteatoma was performed.
Ten cholesteatoma and four deep meatal skin specimens were analysed for
gelatinase activity at molecular weights corresponding to MMP-2 and MMP-9 using
Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS PAGE) Zymography.
Gelatinase activity at 72 kDa and 92 kDa was investigated. Western blotting was
employed using primary monoclonal antibodies to provide a qualitative assessment
of MMP-2 and MMP-9. Non-parametric data analysis using the Mann-Whitney U test
did not show a significant difference in expression of MMP-2 (P = 0.51) or MMP-9
(P = 0.14) between the two tissue types. Western blotting showed the presence of
both MMP-2 and MMP-9 in the majority of specimens, both cholesteatoma and deep
meatal skin.
PMID- 9762498
TI - Chest computerized tomography scanning in patients presenting with head and neck
cancer.
AB - Between 1 to 16% of patients with head and neck squamous cell carcinoma (HNSCC)
have synchronous tumours; the majority (> 50%) occurring within the lung.
Previous studies have relied upon endoscopy and chest radiographs. The aim of
this study was to determine the incidence of synchronous intrapulmonary tumours
in this group of patients using computerized tomography (CT) scanning. Over 36
months, 111 consecutive patients were assessed at presentation by contrast
enhanced CT scanning from the skull base to the diaphragm. Chest scans showed
intrapulmonary lesions in 17 patients and 10 have, with time, been confirmed as
neoplastic. These allowed treatment of three primary bronchial carcinomas
following radical treatment of the index tumour and cancellation of radical
treatment in five patients with metastases. Two patients with possible metastases
at presentation underwent radical treatment to the index tumour with subsequent
follow-up confirming metastatic chest disease. All 10 patients eventually died of
either locoregional or metastatic disease. This is one of the first prospective
reports of chest scanning in patients with head and neck cancer. An additional
chest scan in this group, many of whom undergo a staging scan of the neck,
requires an extra 10 min with no further contrast and in this study yielded a
synchronous tumour rate of 9%.
PMID- 9762499
TI - Vocim analysis of laryngeal images: is breathiness related to the glottic area?
AB - The aim of this study was to determine the relationship between glottic space and
breathy voice. Using a new computerized method of analysing the glottic area of
video images with the Vocim computer system, 16 patients with a vocal cord palsy
and 31 with non-organic dysphonia were examined. The quality of the breathy voice
was assessed and correlated with the size of the glottic space during phonation.
There was a positive (r = 0.70) correlation between glottic area and breathy
voice in vocal cord palsy. There was no correlation (r = 0.002) in non-organic
dysphonia. Therefore in this study population, for vocal cord palsy, glottic area
is the dominant feature in determining voice quality. This relationship is not
maintained in non-organic dysphonia.
PMID- 9762500
TI - Laser Assisted Uvulopalatoplasty: an objective evaluation of the technique and
results.
AB - The operation of Laser Assisted Uvulopalatoplasty (LAUP) as described by Kamami
is now becoming more commonly used in the treatment of snoring and obstructive
sleep apnoea. The authors have treated 95 snoring patients, varying the lengths
of the soft palate incisions and percentage of uvula excised. All operations were
carried out under general anaesthesia using a CO2 laser. Pilot studies showed
incisions that are 25% of the distance between the free edge of the soft palate
to the hard palate junction and excision of 50% of the uvula give good results
with minimal complications. A further study using these parameters was conducted
and postoperative evaluation including polysomnography confirmed this procedure
to be effective in reducing snoring levels both subjectively and objectively.
PMID- 9762501
TI - Ototoxicity and topical eardrops.
AB - Topical aminoglycoside ear drops are theoretically acknowledged to be potentially
ototoxic when administered in the presence of a tympanic membrane perforation.
Although the development of clinical ototoxicity appears to be rare, nine well
documented and incontrovertible cases (12 ears in total) of iatrogenic topical
vestibulotoxicity are presented, representing the largest series in the English
language world literature to date. All patients were treated with the topical
gentamicin-containing ear drops Garasone, (betamethasone sodium phosphate and
gentamicin sulphate) for prolonged periods. Toxicity was found to be primarily
vestibular rather than cochlear. Further review of five previously reported cases
in addition to the findings from another four patients identified with topical
ototoxicity are described. Although compensation occurred in unilateral cases the
disability in bilateral cases was typically severe and often resulted in
litigation.
PMID- 9762502
TI - Histological analysis of the greater auricular nerve and its use as a graft.
AB - Many factors are involved in successful nerve grafting. Morphometric similarity
between donor and recipient nerve is one of these factors. A histological study
was undertaken to determine the suitability of the greater auricular nerve as a
graft in head and neck surgery. Nerves were obtained from fresh human cadavers
and evaluated for length, total cross-sectional area, total fascicular cross
sectional area and fascicular number, at three separate points along the nerve.
Comparisons were made with similar studies of the sural and facial nerve. The
study confirms the clinical view that the greater auricular nerve is ideal when
short sections of graft are required in head and neck surgery.
PMID- 9762503
TI - Power-frequency fields and cancer.
AB - There is a widespread public perception that exposure to "EMF" is linked to
cancer. This concern stems largely from a few epidemiological studies that appear
to show an association between cancer and residence near power lines. However,
the epidemiological evidence for such a link falls far short of that needed to
conclude that a causal relationship exists, and examination of the biophysics
leads to the conclusion that biological effects are implausible at the field
strengths encountered in environmental settings. In a case such as this, where
the epidemiological evidence for a link between an agent and a disease is weak to
nonexistent and the effect is biophysically and/or biochemically implausible,
laboratory evidence becomes critical for risk evaluation. The mechanisms of
carcinogenesis are sufficiently well established that laboratory studies can be
used to assess whether an agent has carcinogenic potential. There are
approximately 100 published reports that have looked for evidence that power
frequency fields have genotoxic or epigenetic activity. These studies have found
no replicated evidence that power-frequency fields have the potential to either
cause or contribute to cancer. Of the few studies that have shown some evidence
for carcinogenic activity, most have used exposure conditions with little
relevance to real world exposure, none have been replicated, and many have failed
direct attempts at replication. In conjunction with the epidemiology and
biophysics, this leads to the conclusion that a causal association between power
frequency fields and cancer is not only unproven, but rather unlikely.
PMID- 9762504
TI - Biomedical concerns in wireless communications.
AB - The last decade witnessed rapid development of new communication technologies and
their broad acceptance at large. Digital wireless telephones are the most popular
example of these technologies. There are two aspects of these technologies that
are related to human health and therefore biomedical engineering. First, antennas
of some devices are in close proximity to the user's head, thus possibly
producing locally excessive energy deposition. Second, radiofrequency (RF)
signals emitted are amplitude modulated at extremely low frequencies, potentially
eliciting different biological effects from those of unmodulated RF radiation.
Recent progress in addressing these two issues is reviewed in this article.
Another area of research and concern not covered here is electromagnetic
interference (EMI) with medical devices. Considerable research has been conducted
on the development of a new method for numerical and experimental evaluation of
the spatial distribution of the power deposition in tissue. Improved implantable
electric field probes and automated scanning systems are presently available.
With respect to numerical evaluation of electric fields in tissue, the finite
difference time domain (FDTD) technique has proven to be a useful and accurate
tool. These developments also are critical in view of the regulatory requirements
now imposed on mobile/portable transmitters. Similarly, significant research
effort on biological effects of modulated fields has been undertaken. Most of the
studies are still in progress, and further research agendas have been proposed.
PMID- 9762505
TI - Evolution of the cohort study.
PMID- 9762506
TI - Outcomes in cohort studies.
PMID- 9762507
TI - Methodological issues for biomarkers and intermediate outcomes in cohort studies.
PMID- 9762508
TI - Exposure measurement in cohort studies: the challenges of prospective data
collection.
AB - Cohort study designs have several advantages over case-control studies in terms
of exposure measurement. If exposure measurement occurs before disease
occurrence, cohort studies are much less prone to differential measurement error.
Prospective data collection should also reduce measurement error due to poor
recall of past exposures. The primary drawback of cohort studies is the large
sample size leading to high data collection costs. Several approaches to reduce
such costs have been discussed in this presentation, such as selection of lower
cost measurement methods and fully measuring the exposure only on a subsample of
the cohort (e.g., nested case-control design). However, other innovative
approaches to reduce costs are needed. In addition, study reviewers should also
consider that the higher costs are justified in relation to the several benefits
of this study design, which include not only less measurement error, but also
less susceptibility to selection bias and often the ability to study multiple
disease outcomes. Improving the accuracy of exposure measurement is increasingly
important for cohort studies as we move on to the study of exposures that are
difficult to measure or to those with lower relative risks of disease. In such
studies, attenuation of the relative risk by the effects of measurement error can
lead to failure to detect an association between exposure and disease. The
validity of exposure measurements could be improved by a better understanding of
the biologically active agent and etiologically important time period of the
exposure-disease relation, and by incorporating these into the measure. Long-term
cohort studies which cover the etiologically relevant time period could improve
the accuracy of measures of exposures by use of repeated biologic measures or
repeated updates of self-reported exposures. Measurement error also can be
reduced by judicious choice of a cohort to study and by careful attention to
quality control procedures. Continued emphasis on the evaluation and improvement
of the measurement properties of instruments used in epidemiologic studies will
improve the validity of the results of cohort studies.
PMID- 9762509
TI - Retaining and tracking cohort study members.
AB - The only way to ensure that losses to follow-up have not biased study results is
to keep all losses to an absolute minimum. Since more complete follow-up leads to
the identification of additional disease events, the effort spent in locating
cohort members also improves the precision as well as the validity of the study
results. This presentation reviewed approaches for maximizing retention and
minimizing loss to follow-up, including the importance of communicating the
expectations of participation and collecting personal information at baseline,
conducting frequent personal and mail contact, and providing incentives for
participation. Response rates can be increased by repeated attempts to contact
each cohort member using a range of approaches (e.g., telephone, mail, personal
contacts) and by other procedures specific to mailed questionnaires, telephone
interviews, or in-person visits. Lost participants can be traced by use of the
NCOA system and contact with other local, state, and national sources. Finally,
for those participants who are unable or unwilling to continue or who cannot be
found, proxy interviews and/or use of the National Death Index may provide
information on the outcomes of interest and vital status. Additional research
evaluating the efficacy of the various approaches to retention and tracking is
needed to help investigators learn how to best apply study resources to retain
and keep track of the largest possible number of cohort members.
PMID- 9762510
TI - Quality assurance and quality control in longitudinal studies.
AB - As we have presented, it is evident that cohort studies are confronted with their
own special, non-trivial issues of quality assurance and quality control. Such
studies are typically large-scale designs and involve an extensive amount of data
to be collected and processed, the quality of which depends on a variety of
factors related to study personnel and equipment. The fact that data are
collected over an extended period of time and at several centers greatly
increases the magnitude of the data processing task, significantly increasing the
likelihood of discrepancies and measurement error in the data. As presented in
tables 1 and 2, the quality assurance and quality control procedures span the
entire course of the study and include a multitude of tasks. Such tasks are
delegated to various committees and/or are undertaken by participating centers,
all of which must take responsibility for understanding, implementing, and
following through on all procedures that maximize data quality. The quality of
the quality assurance/quality control process is highly correlated with the
quality of the communication within and between centers and all researchers.
Maintaining standardization of procedures across centers and long-term stability
of equipment and analytic procedures are integral components of quality control.
In conclusion, the magnitude of the quality control process in a multicenter
longitudinal study should not be underestimated, requiring a significant
commitment of study resources. The quality control process is key to the
integrity of the study, and an integral part of the design of the study. In a
well-designed study, with a good quality control process and dedication to the
process by the research team, the validity of the conclusions of the cohort study
can be established.
PMID- 9762511
TI - Population-based cohort studies.
PMID- 9762512
TI - Approaches for conducting large cohort studies.
PMID- 9762513
TI - Developments in occupational cohort studies.
PMID- 9762514
TI - Use of computerized record linkage in cohort studies.
PMID- 9762515
TI - New techniques for the analysis of cohort studies.
PMID- 9762516
TI - Perspective: cohort studies.
PMID- 9762517
TI - The biological significance of plasmalogens in defense against oxidative damage.
AB - The phospholipid class of plasmalogens is ubiquitously found in considerable
amounts as a constituent of mammalian cell membranes and of plasma lipoproteins.
Plasmalogens are more susceptible to oxidative reactions compared to their fatty
acid ester analogues, due to the reactivity of their enolether function. Studies
on plasmalogen-deficient cell lines lead to the proposal that these ether lipids
serve as endogenous antioxidants. No clear conclusions regarding the
antioxidative effects of plasmalogens could be drawn from studies in patients of
different ages with peroxisomal deficiency disorders. A defective peroxisomal
plasmalogen synthesis is not necessarily associated with other defects in the
metabolism of peroxisomes, as has been established in a cell line recently. In
different mammalian tissues a decrease of plasmalogens with age was described.
Moreover, an accumulation of plasmalogen oxidation products was measured in brain
of old cattle compared to young ones. In pathologic conditions associated with
oxidative stress like in spinal cord ischemia and reperfusion, plasmalogen levels
varied inversely according to the oxidative burden. Oxidation products of
plasmalogens increased with time of ischemia in infarcted porcine heart tissue.
Enrichment of lipoproteins with plasmalogens increased their oxidative
resistance, which was diminished in the case of LDL particles in patients with
coronary arteriosclerosis. In red cell membranes plasmalogens were reduced with
donor age and in hyperlipidemia. Under lipid lowering therapy with lovastatin an
increase was observed, indicating a possible antioxidative impact of this
treatment. Taken together, there is good evidence that plasmalogens are effective
as endogenous antioxidants. However, more experimental approaches not confounded
by other lipolytic processes are needed to establish this role of plasmalogens.
PMID- 9762518
TI - The importance of inflammatory mechanisms in Alzheimer disease.
AB - Lesions in such chronic neurodegenerative disorders as Alzheimer disease (AD),
Parkinson disease, the parkinsonism dementia complex of Guam, and amyotrophic
lateral sclerosis have associated with them a variety of proteins known to be
involved in inflammatory processes. This is particularly true of AD, where
inflammatory reactions are thought to be important contributors to the neuronal
loss. Proteins present include complement proteins, complement inhibitors, acute
phase reactants, inflammatory cytokines, proteases, and protease inhibitors.
Studies of cultured human astrocytes and microglia, obtained from postmortem
brain, have established that nearly all of these proteins are produced by one or
another of these cell types. Human neurons also produce many inflammatory
proteins and their inhibitors, creating complex interactions. Accumulations of
amyloid and extracellular tangles apparently act as irritants, causing the
activation of complement, the initiation of reactive changes in microglia, and
the release of potentially neurotoxic products. Such products include the
membrane attack complex, oxygen free radicals, and excess glutamate. Twenty
epidemiological studies that have been published to date indicate that
populations taking antiinflammatory drugs have a significantly reduced prevalence
of AD or a slower mental decline. One small clinical trial with indomethacin
showed arrest of the disease over a six-month period. Therapeutic intervention in
key inflammatory processes holds great promise for the amelioration of AD and
possibly other neurodegenerative disorders.
PMID- 9762519
TI - Human urothelial carcinomas--a typical disease of the aged: the clinical utility
of human chorionic gonadotrophin in patient management and future therapy.
PMID- 9762520
TI - The two-process model of cellular aging.
AB - To understand the mechanism of aging at the cellular level, cellular senescence
has been extensively studied as an experimental model of aging in vitro. Although
several hypotheses have been proposed for the mechanism of cellular senescence,
none of them could give a comprehensive framework to the mechanism. In this
study, we showed our results of extensive computer simulation designed to
identify possible molecular models of cellular senescence. By examining
representative cases of various molecular models, we elucidated the requirements
for the plausible mechanism of cellular senescence. Based on these simulation
results, we proposed a new molecular model of cellular senescence--the two
process model. In this model, we assumed that two independent, but time-aligned
regulatory processes functioned in individual cells. We defined these two
processes as S- and C-processes. The S-process mainly determines the rate of
decline in the proliferative potential of the cell population. The simulation
results suggested that the growth-inhibitory cell-to-cell interaction was
required to drive the S-process. The C-process determines the latent
proliferative potential of individual cells. The effector genes for the C-process
are suggested to be regulated by a certain threshold-type mechanism. Both growth
kinetics and senescence-associated gene expression were generated with high
accuracy by the combined effect of these two processes. We also succeeded in
simulating the effects of simian virus 40 large T antigen and its inducible
variant on cellular senescence. From these theoretical considerations, we discuss
the validity of the two-process model and the possible involvement of the
heterochromatin structure as a determinant of the replicative lifespan of cells.
PMID- 9762521
TI - A strategy for identifying biomarkers of aging: further evaluation of hematology
and blood chemistry data from a calorie restriction study in rhesus monkeys.
AB - We examined a dataset derived from a battery of hematology and blood chemistry
tests to identify candidate biomarkers of aging in a sample of 33 male rhesus
monkeys (Macaca mulatta) ranging in age from 4-27 years. About half this sample
comprised an experimental group subjected to 30% calorie restriction for six to
seven years compared to the control group fed the same nutritionally fortified
diet to approximate ad lib levels. Variables that met the following criteria were
selected: (1) longitudinal change within the cohorts of control monkeys; (2)
cross-sectional correlation with age across the adult lifespan in the control
group; (3) stability of individual differences within all groups; and (4) no
obvious redundancy with other selected variables. Five variables emerged from
this step-wise selection, including the percentage lymphocytes, and serum levels
of alkaline phosphatase, albumin, creatinine, and calcium. These variables were
then submitted to a principal component analysis, which yielded a single
component accounting for about 58% of the total variance. Based on this marked
degree of covariance, these candidate biomarkers of aging could be combined into
a biological age score (BAS) for the control and experimental groups. When
chronological age was regressed onto BAS, the slopes of the control and
experimental groups could be compared. Although a trend toward a slower aging
rate in calorie-restricted monkeys was apparent, this analysis did not detect a
statistically significant difference in the rate of aging between these groups
estimated by this index. Despite this result, a logical strategy was confirmed
for expanding the search for candidate biomarkers of aging to apply to this and
to other studies assessing interventions that purport to affect the rate of aging
in long-lived species.
PMID- 9762522
TI - Effect of high-glucose concentrations on the expression of collagens and
fibronectin by fibroblasts in culture.
AB - Extracellular matrix macromolecules such as collagen and fibronectin are
progressively altered during aging and age-related diseases like diabetes. We
investigated the effect of high-glucose concentration (mimicking diabetic
conditions) and the influence of in vitro cell aging [comparing 4th-passage
fibroblasts (P4) to 15th-passage fibroblasts (P15)] on collagen and fibronectin
synthesis. Fibroblasts were incubated at postconfluency with radiolabeled
precursors, [3H] proline for collagen, [35S] methionine for fibronectin. We
report that in control conditions (5 mM glucose) collagen III production
increased with in vitro cell aging. High glucose concentrations (10 and 15 mM)
increased specifically collagen III synthesis both at the mRNA and protein
levels, without alteration of collagen I production in P4 and P15 cells.
Fibronectin synthesis was also increased both during in vitro cell aging and in
high glucose-treated P4 fibroblasts. Taken together, these data suggest
similarities between changes of phenotypic expression of collagen and fibronectin
induced by in vitro cell aging and conditions imitating diabetes.
PMID- 9762523
TI - Identification of altered expression of ADP/ATP translocase during cellular
senescence in vitro.
AB - In this study, we have used the mRNA differential display technique to
investigate the changes in gene expression that occur in the process of cellular
aging. A number of cDNAs whose corresponding mRNAs are either increasingly or
decreasingly expressed in senescent cells were thereby isolated. Through DNA
sequencing, one of these differentially displayed mRNAs was identified as
mitochondrial ADP/ATP translocase. The altered expression of ADP/ATP translocase
in different stages of senescent fibroblasts was further confirmed by Northern
blots and semiquantitative RT-PCR. Our results demonstrate that expression of
ADP/ATP translocase is progressively decreased during the process of in vitro
cellular senescence. Further analyses with MTT assays indicate that the decreased
expression of ADP/ATP translocase in senescent cells is in parallel with the
decline of mitochondrial functions, suggesting that altered expression of this
important mitochondrial enzyme might play an active role in the process of
cellular senescence.
PMID- 9762524
TI - The effect of exercise training in cold on shivering and nonshivering
thermogenesis in adult and aged C57BL/6J mice.
AB - To understand the mechanisms of improvement of cold-induced heat production in
aged mice following exercise training, the relative contributions of shivering
and nonshivering thermogenesis to cold-induced metabolic responses were assessed
in adult and aged C57BL/6J male mice, which inhabited sedentarily at room
temperature, or were subjected either to a regimen of moderate intensity exercise
training at 6 degrees C, or to sedentary repeated exposures to the same
temperature. The main findings were that (1) aged mice had greater cold-induced
nonshivering thermogenesis, but lower shivering than adult mice; (2) exercise
training in a cold environment enhanced cold-induced nonshivering thermogenesis
in adult mice, but suppressed it in aged animals; (3) exercise training in a cold
environment increased shivering thermogenesis in both age groups, but this
increase was much greater in aged mice; (4) the increase of cold-induced
shivering thermogenesis was mainly responsible for increased cold tolerance in
aged mice after exercise training in a cold environment.
PMID- 9762525
TI - Age-associated differences in neutrophil oxidative burst (chemiluminescence).
AB - Phagocytic defensive functions consist of a sequence of events, including
migration, phagocytosis, secretion, and the release of reactive oxygen species
(ROS). The last of these (also called "oxidative burst") has not received due
attention in the elderly, even though it can be considered the most important
event in the process of killing an invading microorganism. The aim of the present
study was to investigate the oxidative burst activity of polymorphonuclear
neutrophil leukocytes (PMNs) in relation to age, using a technique that
specifically identifies ROS production: luminol-amplified chemiluminescence
(LACL). Besides the use of LACL, a particular feature of the study was the use of
five rather than just one or two different stimulants: two particulate (Candida
albicans and zymosan) and three soluble ones [N-formyl-methionyl-leucyl
phenylalanine (fMLP), phorbol 12 myristate 13 acetate (PMA), and
polyanetholesulfonate (liquoid)]. This approach allowed us to observe a dichotomy
between the effects of Candida and zymosan (particulates), which were not
significantly different in the elderly subjects compared to the young controls,
and those of fMLP, PMA, and liquoid (solubles), which showed a significant
reduction in LACL in the elderly group. Considering the different results
obtained with the various stimulants adopted that are all believed to have NADPH
oxidase as a common final target of oxidative burst, it may be postulated that
aging can influence the different transductional pathways in different ways.
PMID- 9762526
TI - Environmental influence on age-related changes of human lymphocyte membrane
viscosity using severe combined immunodeficiency mice as an in vivo model.
AB - Peripheral blood lymphocytes (PBL) of healthy elderly people show increased
plasma membrane viscosity compared to young subjects, that inversely correlates
with lymphocyte proliferation after mitogen stimulation in vitro. Maintenance of
a constant membrane viscosity, which is necessary for proper cell function, is
crucially dependent on the membrane lipid composition. The cellular lipid
metabolism, and thus lymphocyte function, may be subject to modulation by diet or
drugs. To study the susceptibility of membrane viscosity to environmental
conditions, we established an in vivo model using severe combined
immunodeficiency (SCID) mice: human peripheral blood lymphocytes from healthy
young and old subjects were engrafted for three days intraperitoneally into SCID
mice to offer identical environmental conditions. First, we demonstrate that
human lymphocytes can take up and utilize murine lipoproteins: engrafted human
PBL can participate in the mouse lipid metabolism, and an exchange of membrane
lipids in vivo is, therefore, possible. Second, plasma membrane viscosity was
determined before and after engraftment: before engraftment, PBL from the elderly
showed a significantly higher membrane viscosity than that from young controls,
but this difference vanished during engraftment into SCID mice, wherein cells
from both age groups exhibited nearly identical values. It was, therefore,
concluded that lymphocyte membrane viscosity is influenced by environmental
factors, and that the age-related increase is, in principle, reversible.
PMID- 9762527
TI - Effect of dehydroepiandrosterone (DHEA) on intestinal mucosal immunity in young
adult and aging rats.
AB - The present study assesses the effectiveness of oral DHEA on the intestinal
mucosal immune response in aging rats. Young adult (6 months) and aging (21
months) female rats received powdered rat chow with or without 0.2% DHEA for 23
days. The animals were immunized intraduodenally with either cholera toxin (CTx)
or vehicle alone and boosted two weeks later. Seven days after boosting, serum,
bile, small intestinal tissue, and liver were collected for analysis. Anti-CTx
IgA antibody titers were measured in serum and bile and the concentration of anti
CTx antibody containing cells (ACCs) in the small intestinal lamina propria and
liver were determined by quantitative immunohistochemistry. Intergroup
comparisons indicated that there was only one significant difference in serum and
none in bile anti-CTx IgA titers between CTx-immunized animals fed DHEA or the
diet alone. Immunohistochemical analysis determined that the density and
distribution patterns of ACCs within the lamina propria were unaffected by DHEA.
Both DHEA-treated and control young immunized animals exhibited similar numbers
of ACCs. Only 40% of the aging rats responded to intraduodenal immunization with
CTx, as determined by the presence of ACCs in the intestine, regardless of the
presence or absence of DHEA in the diet. These data suggest that DHEA in the diet
does not enhance the intestinal mucosal immune response to intraduodenal CTx in
either young adult or aging rats.
PMID- 9762528
TI - Norepinephrine kinetics in older women: relationship to physical activity and
blood pressure.
AB - The sympathetic nervous system participates in the regulation of carbohydrate,
lipid, and energy metabolism, and has been implicated in the pathogenesis of
hypertension and obesity. Increased sympathetic nervous system activity with age
may alter disease risk and contribute to the development of certain chronic
diseases. Thus, we examined possible determinants of sympathetic nervous system
activity in older normotensive women from infusions of tritiated norepinephrine
(NE) to estimate rates of norepinephrine appearance and clearance. A secondary
aim was to examine the association between norepinephrine kinetics and mean
supine arterial blood pressure. Twenty-two older women (65.7 +/- 5.7 years) were
characterized for resting NE kinetics, body composition, body fat distribution,
peak aerobic capacity, leisure time physical activity energy expenditure (LTA),
dietary carbohydrates, and daily energy intake. Analysis of univariate
correlations revealed that only the LTA was significantly correlated with plasma
NE appearance (r = 0.54, p < 0.01). Stepwise regression analysis identified LTA
as the only significant predictor of plasma NE appearance rate with a total R2 =
0.29. The waist-to-hip ratio was selected as the only significant predictor of
mean arterial blood pressure with an R2 = 0.30. When forced into the model,
plasma NE appearance explained only 1% of the unique variance in mean arterial
blood pressure. In summary, we found that: (1) higher levels of physical activity
are related to higher plasma NE appearance in older women; (2) greater central
body fatness is an independent predictor of mean arterial blood pressure; and (3)
plasma NE appearance rate is a minor contributor to variation in mean arterial
blood pressure in older, normotensive women.
PMID- 9762529
TI - Health care and the market.
PMID- 9762530
TI - Caring for "difficult" patients.
PMID- 9762531
TI - Caring for "difficult" patients.
PMID- 9762532
TI - Remodelling IRBs.
PMID- 9762533
TI - Deaf culture, cochlear implants, and elective disability.
AB - The use of cochlear implants, especially for prelingually deafened children, has
aroused heated debate. Members and proponents of Deaf culture vigorously oppose
implants both as a seriously invasive treatment of dubious efficacy and as a
threat to Deaf culture. Some find these arguments persuasive; others do not. And
in this context arise questions about the extent to which individuals with
disabilities may decline treatments to ameliorate disabling conditions. When they
do so, to what extent may they call upon society to provide supportive services
and accommodations?
PMID- 9762534
TI - Multiplex genetic testing. The Council on Ethical and Judicial Affairs, American
Medical Association.
AB - As panels of multiple genetic tests become increasingly available, clinicians
face new challenges in helping patients understand the nature of these tests.
Diagnostic tests for conditions that inevitably lead to disease, "susceptibility"
tests that reveal heightened risk of disease, and tests for carrier status raise
different concerns about informed consent and pose different needs for
counseling. Clinicians must understand the implications of different kinds of
tests, and of different arrays of tests in multiple panels, if multiplex tests
are to be used wisely in clinical practice.
PMID- 9762535
TI - Meaning what you sign.
PMID- 9762536
TI - Should psychiatrists serve as gatekeepers for physician-assisted suicide?
PMID- 9762537
TI - What could have saved John Worthy?
PMID- 9762538
TI - Autonomy and assisted suicide. The execution of freedom.
AB - Proponents of assisted suicide who base their arguments on autonomy err in ways
that are little attended to. In the absence of a substantive theory of the good,
in neither a descriptive nor an ascriptive sense can the concept of autonomy
distinguish those acts that should be morally prohibited from those that may be
permitted. And to impose a particular theory of the good, whether individual
liberty or the sanctity of life, violates the autonomy of those who do not share
a commitment to that theory.
PMID- 9762539
TI - Adam and the implant.
PMID- 9762540
TI - Cash up front.
PMID- 9762541
TI - Grading and scoring in histopathology.
AB - In many areas of histopathology a nominal category, such as a diagnosis of breast
carcinoma, does not give enough information for the referring clinician to make
decisions about patient prognosis and treatment. Therefore scoring and grading
systems have been developed which provide additional information. This article
reviews the principles behind these systems with particular reference to the
relationships between the natural clustering (or nonclustering) of cases and the
imposition of arbitrary class boundaries on such distributions. The difference
between real numbers and the ordinal categorical numeric labels, which are often
produced by histopathology scoring systems, is discussed. The reproducibility of
scoring and grading systems is reviewed and generic suggestions are given for
developing new systems and for their validation.
PMID- 9762542
TI - Gains and losses of CD44 expression during breast carcinogenesis and tumour
progression.
AB - AIMS: This study was performed to investigate whether the CD44 immunophenotype of
breast lesions correlates with the clinical evolution and prognosis of breast
cancer. METHODS AND RESULTS: One-hundred and fifty-two routinely processed
normal, benign and malignant breast tissue samples were investigated by the
following monoclonal antibodies: CD44s (F10-44-2), CD44v3 (3G5), CD44v4 (11.10),
CD44v5 (VFF-8), CD44v6 (VFF-18), CD44v7 (VFF-9), CD44v9 (11-24) after wet
autoclave pretreatment for antigen retrieval. We found that: (1) in normal breast
tissues luminal epithelial cells lacked detectable CD44 in contrast to basal
cells, which constitutionally expressed CD44s, v3, v5 v6 and v9 isoforms; (2) in
the intraductal compartment of benign hyperplastic lesions, there was scattered
or focal staining for CD44s, v5, v6, v7 and v9 isoforms; (3) in neoplastic
lesions restricted neo-expression of CD44v3 and v4 was detected; and (4) the CD44
immunophenotype of invasive breast carcinomas was influenced largely by
differentiation grade, steroid receptor status of the tumours and significantly
correlated with metastatic involvement of the axillary lymph nodes. CONCLUSIONS:
Qualitative and quantitative changes of CD44 expression are implicated in early
stages of breast carcinogenesis. The restricted neo-expression of certain CD44
isoforms in breast neoplasias suggests that CD44 might be a potential target for
future antibody-based tumour therapy.
PMID- 9762543
TI - Apoptosis in nasopharyngeal carcinoma as related to histopathological
characteristics and clinical stage.
AB - AIMS: We investigated the significance of apoptosis, using the terminal
deoxynucleotidyl transferase mediated dUTP-digoxigenin nick end-labelling method,
in nasopharyngeal carcinoma biopsy samples. METHODS AND RESULTS: The apoptotic
index (AI) in 50 nasopharyngeal carcinomas was compared with various
histopathological features and clinical stage. Also, the AI was correlated with
p53, bcl-2 and Ki67 expression by immunohistochemistry. In histopathological
studies, the AI was significantly higher in mixed cellular type (MC) than in
keratizing squamous cell type (KS) and spindle cell type (SC) (P < 0.001) which
worsens prognosis. In tumour stage analyses, AI was higher in early stage (stage
2 and 3) than in high stage (stage 4). In addition, there was a significant
correlation between the AI and p53 expression (P < 0.001) but not with
proliferative activity (P = 0.15). In NPC containing p53 protein positive tumour
cells, there was a significantly higher apoptotic rate. CONCLUSIONS: These
findings indicate that apoptosis is related to type and stage of nasopharyngeal
carcinoma. They also confirm the role of p53 in regulating tumour apoptosis.
PMID- 9762544
TI - Apoptosis and expression of bcl-2 protein are inverse factors influencing tumour
cell turnover in primary carcinoid tumours of the lung.
AB - AIMS: This study evaluates potential regulating factors in primary pulmonary
carcinoid tumours, 16 typical and four atypical samples, with special emphasis on
apoptosis and the bcl-2 gene family. Furthermore, p53-related oncogenes were
analysed in a search for associated biological parameters. METHODS AND RESULTS:
The in-situ end-labelling technique (ISEL) was used to determine apoptotic cells,
in addition to immunohistochemical methods, which were used to investigate the
expression of the Ki67 antigen (avidinbiotin complex (ABC) method) and bcl-2, bcl
x, p53, p21/waf1, p27 and mdm-2 proteins (catalysed reporter deposition (CARD)
technique). The incidence of apoptotic tumour cells was significantly enhanced in
typical carcinoids. The bcl-2 protein was expressed to a higher degree in
atypical carcinoids, which displayed a higher proliferative capacity as well. In
contrast, bcl-x was observed predominantly in so-called typical carcinoids. The
tumour cell turnover index was the most distinguishing parameter between both
entities. All carcinoid tumours failed to show a staining for p53, p21/waf. p27
and mdm-2 proteins. CONCLUSIONS: The different biological behaviour of the
carcinoid tumours under study seems to be influenced by the bcl-2 gene family
preventing programmed cell death. We speculate that this results in a more
aggressive course in atypical carcinoid tumours.
PMID- 9762546
TI - Skeletal muscle regeneration mimicking rhabdomyosarcoma: a potential diagnostic
pitfall.
AB - AIMS: We report three cases of skeletal muscle regeneration, of which two
mimicked a small round cell tumour, especially a rhabdomyosarcoma. METHODS AND
RESULTS: One case presented as an intramuscular mass, located in the right
quadriceps of a 12-year-old male; the second patient was a 25-year-old football
player who complained of painful left peroneus muscles; the third patient was a
22-year-old male who underwent an amputation of the right thigh 5 days after
right leg amputation due to limb crush. Histologically, muscle biopsy specimens
showed a proliferation of small round cells, either infiltrating the striated
muscle in a diffuse manner or growing within and around necrotic myofibres.
Immunohistochemically and ultrastructurally, the cellular population was composed
of two types of cells: phagocytic cells the nuclei of which occasionally showed a
wreathlike arrangement around necrotic myofibres resulting in structures
resembling Langhans-type multinucleated giant cells, and proliferating satellite
cells showing enlarged nuclei, prominent nucleoli, mitotic figures, myogenic
differentiation and fusion features in order to form regenerating myotubes.
CONCLUSIONS: Muscle regeneration is a benign process that may occasionally mimic
a small round cell proliferation resembling a lymphoma or an alveolar
rhabdomyosarcoma with which it should not be confused.
PMID- 9762545
TI - Differentiation of desquamative interstitial pneumonia (DIP) from pulmonary
adenocarcinoma by immunocytochemistry.
AB - AIM: After a misdiagnosis of pulmonary adenocarcinoma as desquamative
interstitial pneumonia (DIP), we investigated whether immunohistochemical markers
could differentiate these conditions. METHODS AND RESULTS: Three cases of DIP and
one pulmonary adenocarcinoma masquerading as DIP were studied by light and
electron microscopy. All cases were mucin-negative. The cases of DIP were CD68
positive but cytokeratin-negative. The adenocarcinoma was cytokeratin-positive
(AE1/3 and CAM5.2), as well as showing some CD68-positive cells. Markers for
carcinoma (CEA, Ber-EP4, and Leu M1) were negative in all cases.
Ultrastructurally the adenocarcinoma appeared to be derived from Type II
pneumocytes. CONCLUSION: Before a diagnosis of DIP is made, cytokeratin markers
should be used.
PMID- 9762548
TI - Metallothionein expression in carcinoma of the gallbladder.
AB - AIMS: Metallothioneins (MT) are sulphur-rich, low molecular-weight, intracellular
metal-binding proteins with a possible role in carcinogenesis of some human
tumours. Metallothionein expression in gallbladder cancer has not been studied
previously. METHODS AND RESULTS: Immunohistochemical expression of
metallothionein was studied in 42 gallbladders (27 cases of carcinoma of the
gallbladder, eight chronic cholecystitis and seven cases of normal gallbladder).
Metallothionein expression was significantly higher in cases with carcinoma of
the gallbladder (70.37%) as compared to chronic cholecystitis (25%) and normal
gallbladders (0%). There was a trend suggestive of increasing MT expression with
increasing histological dedifferentiation of carcinoma of the gallbladder.
CONCLUSIONS: The increased expression of MT in cases of carcinoma of the
gallbladder may represent an increased exposure to heavy metals, which are known
carcinogens, and may have a role in gallbladder carcinogenesis. Metallothionein
over-expression in carcinoma of the gallbladder may be relevant to the poor
prognosis and chemoresistance seen in these cases.
PMID- 9762547
TI - Relationship between interleukin-6 and proliferation and differentiation in
cholangiocarcinoma.
AB - AIMS: Interleukin-6 (IL-6) has been implicated as a mediator of growth control in
several human neoplasms. The significance of IL-6 expression in human
cholangiocarcinoma was examined in this study. METHODS AND RESULTS: IL-6
expression was examined in 43 surgically resected cholangiocarcinomas and a
cholangiocarcinoma cell line CCKS1, derived from abdominal metastasis of
moderately differentiated adenocarcinoma, by immunohistochemical and in-situ
hybridization techniques. In non-neoplastic bile ducts, IL-6 was constitutively
but weakly expressed. In surgical cases of cholangiocarcinoma, IL-6 was
frequently and strongly expressed in the cytoplasm of well-differentiated
cholangiocarcinoma, while its expression was decreased, and less intense or
absent in moderately and poorly differentiated areas, respectively. IL-6 mRNA was
detected in the cytoplasm of carcinoma cells of two cases of cholangiocarcinomas
positive for IL-6. IL-6 was detected in hepatic bile from two cholangiocarcinoma
cases studied. The proliferation antigen Ki67 was found to be more frequently
expressed in IL-6 negative carcinoma cells than in IL-6 positive carcinoma cells
(P < 0.01). In cultured carcinoma cells line CCKS1, IL-6, IL-6 mRNA and IL-6
receptor alpha chain were detected in the cytoplasm of carcinoma cells,
suggesting an autocrine effect of IL-6 on carcinoma cells. CONCLUSION: IL-6
expression is inversely related to cell proliferation and positively related to
differentiation in cholangiocarcinoma.
PMID- 9762549
TI - Histological demarcation of lateral borders: an unsupportable criterion for
distinguishing malignant melanoma from Spitz naevus and compound naevus.
AB - AIMS: The objective of this study was to determine the validity of sharpness of
lateral margins (an important component of the pattern analysis method) as a
criterion for the histological distinction of naevi from malignant melanoma.
METHODS AND RESULTS: The sharpness of lateral borders in a series of
histologically unequivocal malignant melanomas, Spitz naevi and compound naevi,
chosen at random from dermatopathology slide archives, was determined. The
incidence of poor demarcation of lateral borders in malignant melanomas was about
equal to that of Spitz naevi and was significantly less than in compound naevi.
The sharpness of lateral borders frequently varies with level of sectioning.
CONCLUSIONS: The proposal that malignant melanomas have a significantly greater
incidence of poor demarcation of lateral borders than benign melanocytic
neoplasms (Spitz naevi and compound naevi) was shown to be without validity on
cited empirical grounds as well as theoretical grounds (the lack of constancy of
pattern from a 3-dimensional standpoint).
PMID- 9762550
TI - Familial mediterranean fever and acute myocardial infarction secondary to
coronary vasculitis.
AB - AIMS: We report a case study to elucidate the pathogenesis of polyarteritis
nodosa (PAN) type vasculitis, a rare complication of familial mediterranean fever
(FMF). METHODS AND RESULTS: A woman with amyloidosis complicating FMF underwent a
cadaveric renal transplantation and 5 years later suffered an acute myocardial
infarction secondary to an isolated coronary vasculitis. CONCLUSIONS: The
histopathological findings of the vasculitis were not in keeping with PAN. We
postulated that the pathogenesis of vasculitis in FMF is different from that of
the classic PAN and might be similar to the mechanism of the serosal
inflammation.
PMID- 9762551
TI - Appendiceal inflammation in ulcerative colitis.
AB - AIMS: Previous uncontrolled reports have suggested that appendiceal inflammation
may occur as a discontinuous lesion in ulcerative colitis. This study aims
semiquantitatively to compare the prevalence and histological features of
appendiceal inflammation in patients with ulcerative colitis and Crohn's disease,
using colonic carcinoma and acute appendicitis specimens as controls. METHODS AND
RESULTS: Surgical pathology records and original histological slides for the
period 1980-1994 were examined. The prevalence of appendiceal inflammation in
ulcerative colitis (24/50, 48%), was higher than in colonic carcinoma (5/65, 8%,
P < 0.001), but was similar to that in Crohn's disease (14/27, 52%). Appendiceal
inflammation with caecal sparing was seen in nine out of 24 specimens with
ulcerative colitis (37%), two out of nine (22%) with Crohn's disease and five out
of 65 (8%) with colonic carcinoma. Inflamed appendixes from patients with
inflammatory bowel disease showed histological features typical of ulcerative
colitis and Crohn's disease rather than acute appendicitis and were significantly
less likely to have transmural inflammation. There had been a previous
appendicectomy in 3% of ulcerative colitis patients compared with 8% of colonic
carcinoma specimens and 21% (P < 0.01) Crohn's disease controls. CONCLUSION: In
ulcerative colitis, as in Crohn's disease, appendiceal inflammation commonly
occurs as a skip lesion and histologically resembles the colonic disease rather
than acute appendicitis. The low prevalence of appendicectomy supports the
hypothesis that the appendix itself may have a central role in the pathogenesis
of ulcerative colitis.
PMID- 9762552
TI - Applications of the microbiopsy technique in non-cervical cytology: where
cytology and histology meet.
AB - AIM: To evaluate a recently developed technique allowing the removal and
processing for histology of thick tissue fragments, called microbiopsies, from
noncervical cytology specimens. METHODS AND RESULTS: Forty-five non-cervical
smears from malignant tumours which contained microbiopsies were selected and
processed. Sufficient sections could be cut in most cases for haematoxylin and
eosin and an extensive panel of immunostaining. Seventy-one per cent of
histological slides from the microbiopsies were representative of the tumour and
confirmed the diagnosis. In 29% of the cases they were too small, contained non
representative tissue or showed extensive necrosis. Surprisingly, immunostaining
results were at least the same and often better than those observed in routine
formalin-fixed, paraffin-embedded tissue. Immunostaining profiles allowed
distinction of tumour subtypes. Antigen retrieval techniques could be avoided in
all cases. CONCLUSIONS: Application of the microbiopsy technique in routine
cytology smears containing microbiopsies is helpful, particularly in those cases
in which the diagnosis is not clear on the basis of the cytology smear and in
cases in which there are not enough cytology slides for immunohistochemical
examination.
PMID- 9762553
TI - Pigmented squamous cell carcinoma of nasal cavity.
PMID- 9762554
TI - Primary extraskeletal osteosarcoma of the penis with a malignant fibrous
histiocytoma-like component.
PMID- 9762555
TI - Hepatoid adenocarcinoma of the stomach with extensive neuroendocrine
differentiation and a coexisting carcinoid tumour.
PMID- 9762556
TI - Inverted papilloma-like transitional cell carcinoma of the uterine cervix.
PMID- 9762557
TI - Malignant fibrous histiocytoma in a child's hand.
PMID- 9762558
TI - Paratesticular composite tumour of epididymal-like and mucinous cells of low
malignant potential.
PMID- 9762559
TI - Intestinal nematode parasites, cytokines and effector mechanisms.
AB - Laboratory models of intestinal nematode infection have played an important role
in developing our understanding of the immune mechanisms that operate against
infectious agents. The type of helper T cell response that develops following
infection with intestinal nematode parasites is critical to the outcome of
infection. The early events that mediate polarisation of the helper T cell
subsets towards either Th1 or Th2 during intestinal nematode infection are not
well characterised, but it is likely that multiple factors influence the
induction of a Th1 or Th2 type response, just as multiple effector mechanisms are
involved in worm expulsion. Costimulatory molecules have been shown to be
important in driving T helper cell development down a specific pathway as has the
immediate cytokine environment during T cell activation. If helper T cells of the
Th2 type gain ascendancy then a protective immune response ensues, mediated by
Th2 type cytokines and the effector mechanisms they control. In contrast, if an
inappropriate Th1 type response predominates the ability to expel infection is
compromised. Equally important is the observation that multiple potential
effector mechanisms are stimulated by nematode infection, with a unique
combination operating against the parasite depending on nematode species and its
life cycle stage. Despite the close association between intestinal nematode
infection and the generation of eosinophilia, mastocytosis and IgE it has been
difficult to consistently demonstrate a role for these effector cells/molecules
in resistance to nematode parasites, although mast cells are clearly important in
some cases. It therefore seems that, in general, less classical Th2 controlled
effector mechanisms, which remain poorly defined, are probably important in
resistance to nematode parasites. Thus, our understanding of both the induction
and effector phases remains incomplete and will remain an intense area of
interest in the coming years.
PMID- 9762560
TI - Recent studies on the reproductive biology of the schistosomes and their
relevance to speciation in the Digenea.
AB - The members of the family Schistosomatidae, dioecious Digenea, are discussed with
regard to their distribution, intermediate and definitive host-parasite
relationships. The biological species concept is considered together with the
difficulties of its application to Schistosoma spp. and the Digenea. The
correlation between pairing of adult schistosomes, physical and sexual
development and the maintenance of reproductive potential is emphasised.
Development of the female reproductive system does not depend upon species
specific pairing. In some combinations, e.g., Schistosoma haematobium/Schistosoma
intercalatum and Schistosoma bovis/Schistosoma curassoni, a specific mate choice
system apparently does not exist, whereas it does in other combinations, e.g.,
Schistosoma mansoni/Schistosoma intercalatum. In mixed infections change of mate
may occur and when the opportunity arises heterospecific pairs of worms will
change partners to conspecific pairs. Interspecific pairing in adult schistosomes
will lead to either hybridisation or parthenogenesis. Yet the majority of
schistosomes that inhabit the same definitive host maintain their genetic
identity: specific mate recognition, site selection within the host and
heterologous immunity have been suggested as isolating mechanisms. Experimental
intraspecific crosses have enabled evaluation of the degree to which some
populations separated and became reproductively isolated through pre-mating
isolating mechanisms, indicative of incipient speciation, e.g., the Lower Guinea
and Zaire strains of S. intercalatum. The occurrence and significance of
parthenogenesis in schistosomes and other species of Digenea are discussed. The
consequences of interspecific mating interactions in schistosomes with regard to
parasite epidemiology, interspecific competition and genetic heterogeneity are
debated. Geographical isolation and host specificity represent important pre
zygotic isolating mechanisms. It is suggested that site selection within the host
and heterologous immunity may both reduce interspecific genetic interchange when
digenean parasites utilise the same definitive host.
PMID- 9762561
TI - Relative concentrations of heavy metals in the parasites Ascaris suum (Nematoda)
and Fasciola hepatica (Digenea) and their respective porcine and bovine
definitive hosts.
AB - The concentrations of lead and cadmium determined by electrothermal atomic
absorption spectrometry were significantly higher in the liver and kidney,
respectively, of pigs than in their intestinal nematode parasites Ascaris suum.
There was no clear pattern in the distribution of lead within the ascarids, but
cadmium concentrations were highest in the intestine. A parallel investigation of
cattle naturally infected with the liver fluke, Fasciola hepatica, revealed
interesting differences. Although the cadmium content of F. hepatica was
considerably lower than that in the tissues of cattle, the concentration of lead
in the digenean was on average 172, 53 and 115 times higher than in the muscle,
kidney and liver of the host. Furthermore, there was a significant positive
correlation between the weight of individual F. hepatica and their lead burden.
The lack of appreciable heavy-metal accumulation in A. suum is consistent with
results for the nematode Anguillicola crassus in fish. However, although lead
concentrations in the liver fluke F. hepatica were considerably elevated above
host tissue levels, the degree of heavy-metal accumulation was relatively low
when compared to that of acanthocephalans and cestodes of fish.
PMID- 9762562
TI - Comparison of the levels of intra-specific genetic variation within Giardia muris
and Giardia intestinalis.
AB - The extent of intra-specific genetic variation between isolates of Giardia muris
was assessed by allozyme electrophoresis. Additionally, the levels of allozymic
variation detected within G. muris were compared with those observed between
members of the two major assemblages of the morphologically distinct species
Giardia intestinalis. Four isolates of G. muris were analysed. Three (Ad-120,
150, -151) were isolated from mice in Australia, while the fourth (R-T) was
isolated from a golden hamster in North America. The 11 isolates of G.
intestinalis (Ad-1, -12, -2, -62, representing genetic Groups I and II of
Assemblage A and BAH-12, BRIS/87/HEPU/694, Ad-19, -22, -28, -45, -52,
representing genetic Groups III and IV of Assemblage B) were from humans in
Australia. Intra-specific genetic variation was detected between G. muris
isolates at four of the 23 enzyme loci examined. Similar levels of variation were
found within the genetic groups that comprise Assemblages A and B of G.
intestinalis. These levels of intra-specific variation are similar to those
observed within other morphologically-distinct species of protozoan parasites. We
suggest that the magnitude of the genetic differences detected within G. muris
provides an indication of the range of genetic variation within other species of
Giardia and that this can be used as a model to delineate morphologically similar
but genetically distinct (cryptic) species within this genus.
PMID- 9762563
TI - Blood clotting disorders during experimental sarcocystiosis in calves.
AB - The effects of experimental infection of calves with Sarcocystis cruzi on the
blood coagulation cascade were investigated. Calves were inoculated orally with 1
x 10(5) sporocysts (group S1, n = 6) or with 5 x 10(5) sporocysts of S. cruzi
(group S2, n = 3). A group of eight calves served as non-infected controls (group
C). The animals were bled once during the first 4 weeks of infection and twice a
week thereafter until day 40 p.i. The following parameters were measured:
activated partial thromboplastin time, prothrombin time, thrombin time, reptilase
time, thrombin coagulase time, factors XII, XI, X, IX, VIII:C, VII, V,
prekallikrein, fibrinogen, alpha 2-antiplasmin, antithrombin III, alpha 1
antitrypsin, alpha 2-macroglobulin, haematocrit, haemoglobin, numbers of
erythrocytes and thrombocytes. The infected calves developed acute sarcocystiosis
from 25 (S1) or 29 (S2) days p.i. onwards. During the acute disease,
antiproteases tended to elevated values and thrombocyte counts were generally
reduced. In group S1 prolonged prothrombin time and reduced activities of factors
VII or V were found. In group S2 accelerated prothrombin time and activated
partial thromboplastin time, as well as elevated factor X activities, were
recorded even before the onset of clinical disease at 19 days p.i. While
prothrombin time returned to normal levels thereafter, activated partial
thromboplastin time remained short. Activities of factor V, factor VII and factor
X were significantly reduced in group S2 at the onset of acute sarcocystiosis,
and one of the three calves died at 29 days p.i. The other parameters were not
significantly affected by either dose of infection. No evidence for a classical
disseminated intravascular coagulation syndrome could be found; however, it was
demonstrated that S. cruzi alters plasma coagulation in a dose-dependent way.
PMID- 9762564
TI - Incompatibility of Protopolystoma xenopodis (Monogenea: Polystomatidae) with an
octoploid Xenopus species from southern Rwanda.
AB - Protopolystoma xenopodis is an oviparous monogenean occurring as an adult in the
urinary bladder of the clawed toad Xenopus laevis. Oncomiracidia invade the
host's kidneys where juveniles develop, subsequently migrating to the definitive
site. In central Africa, the tetraploid X. laevis occurs in sympatry with
octoploid congeners, including Xenopus wittei, believed to be the hybrid
derivatives of X. laevis- and Xenopus fraseri-like parental lineages. Twenty
laboratory-raised, naive specimens of an X. wittei-like species from southern
Rwanda were each exposed to 30 embryonated P. xenopodis eggs (at 20 degrees C)
and screened for parasite egg production until 9 months post-exposure. These
toads failed to support the development of gravid parasites (comparable
experimental procedures produce at least 35% prevalence of patent infection in
the natural host X. laevis). Further X. wittei aff. (n = 26) and X. laevis (n =
17) were exposed to P. xenopodis oncomiracidia and dissected at variable times
post-exposure: larvae were able to invade the kidneys of X. wittei aff. and began
feeding and morphological development. Severe mortality of juveniles occurred in
both natural and unnatural hosts between invasion and 39 days post-exposure.
However, while small numbers of parasites persisted in X. laevis, no stages were
found in X. wittei aff. beyond 39 days. Present data demonstrate the
incompatibility of P. xenopodis with X. wittei aff. and are consistent with a
hypothesis that specificity in Protopolystoma-Xenopus systems is determined
primarily by the ability of juveniles to complete development in the host's
kidneys.
PMID- 9762565
TI - Reproductive interference in concurrent infections of two Protopolystoma species
(Monogenea: Polystomatidae).
AB - The prevention of interspecific reproductive interference is one possible
explanation for spatial niche divergence between congeneric monogeneans. However,
there is little direct evidence that reproductive interactions with other species
are potentially deleterious to the majority of parasitic platyhelminths. Xenopus
fraseri-like clawed toads from lowland rainforest in eastern Democratic Republic
of Congo are infected by two species of polystomatid monogenean, Protopolystoma
fissilis and Protopolystoma ramulosus. Both occur as adults in the host urinary
bladder, and exhibit identical copulatory structures and similar body sizes. The
small area of the habitat in relation to parasite body size makes close proximity
inevitable in concurrent infections. Eggs were collected from five naturally
infected hosts: two of these harboured concurrent infections, and three were
infected with P. fissilis only. Eggs from concurrent infections showed reduced
viability (57.6% embryonation, n = 413) compared with those from P. fissilis-only
infections (85.2%, n = 439). This effect may be due to some form of reproductive
interference, possibly failure to develop following interspecific cross
fertilisation.
PMID- 9762566
TI - Viable Cryptosporidium parvum oocysts exposed to chlorine or other oxidising
conditions may lack identifying epitopes.
AB - The intestinal protozoan parasite Cryptosporidium parvum is a known cause of
water-borne disease in humans. The detection of Cryptosporidium oocysts in water
samples relies upon the use of fluorescently labelled antibodies, preferably
using flow cytometry and epifluorescence microscopy. Here we demonstrate that
four commercially available antibodies recognise a similar set of immunodominant
epitopes on the oocyst wall. These epitopes appear to be carbohydrate in nature
and are labile to chlorine treatment and oxidising conditions. Sodium
hypochlorite and sodium meta-periodate reduced the ability of the antibodies to
detect Cryptosporidium oocysts. Damage to the epitopes did not necessarily reduce
the viability of oocysts. This finding may be important for the water industry,
where naturally occurring oxidising conditions or sanitizing treatments could
produce viable oocysts that are undetectable using standard protocols.
PMID- 9762567
TI - A comparison of three different dihydroartemisinin formulations for the treatment
of acute uncomplicated falciparum malaria in Thailand.
AB - We compared the safety and efficacy of three formulations of dihydroartemisinin
for the treatment of acute uncomplicated falciparum malaria in patients who
received a total dose of 600 mg dihydroartemisinin over 5 days. The first group
was treated by dihydroartemisinin produced and formulated in the People's
Republic of China, the second group was treated by dihydroartemisinin produced in
Vietnam but formulated by the Government Pharmaceutical Organization of Thailand
and the third group was treated by dihydroartemisinin produced and formulated by
the Government Pharmaceutical Organization of Thailand. All patients were
admitted to hospital to evaluate safety and efficacy for a total of 28 days. By
the third day of treatment, most patients were blood-smear negative for parasites
and none had serious adverse effects. Minor symptoms such as nausea, dizziness
and headache were similar in the three groups and disappeared after 3 days of
treatment. One-hundred and thirty-three patients completed the 28-day follow-up
period. The cure rates of groups I, II and III were 80%, 85% and 92%,
respectively (P > 0.02). There were no significant differences in fever clearance
or parasite clearance among the three groups. We conclude that the three
formulations of dihydroartemisinin produced and formulated in different countries
were safe and effective in treating uncomplicated falciparum malaria acquired in
Thailand.
PMID- 9762568
TI - Sequence analysis of the major piroplasm surface protein gene of benign bovine
Theileria parasites in east Asia.
AB - Relatively benign Theileria parasites are widespread among cattle in East Asia.
Although the parasites are presumed to be of the Theileria sergenti/Theileria
buffeli/Theileria orientalis group, their taxonomic status and epidemiology have
not been well defined. In the present study, theilerial DNA samples were
collected from various East Asian countries, including Japan, Korea, Taiwan, and
China. DNA sequences encoding a major piroplasm surface protein were amplified by
polymerase chain reaction, followed by cloning into a plasmid vector. More than
20 DNA clones derived from parasite DNA of a single infected animal were examined
for their restriction-fragment-length polymorphism, showing that they were
classified into four major types. Sequence analysis revealed six types of DNA
sequences encoding major piroplasm surface protein with homologies of between 75
and 91%. Of the six sequences, four were identical to those previously reported,
while the other two appeared to be new sequences. Among the DNA clones derived
from a single infected animal, two to three distinct sequences were often found.
Phylogenetic analysis of the six major piroplasm surface protein sequences
indicates that five of the six are closely related to each other, and that all
are distantly related to the homologous genes of Theileria annulata and Theileria
parva. The results suggest that, in addition to those described as T. sergenti/T.
buffeli/T. orientalis, there may be some undefined Theileria species distributed
in East Asia, and that many cattle are infected with mixed populations of
geographically variable Theileria parasites.
PMID- 9762569
TI - In vitro expression of a recombinant paramyosin of Ancylostoma caninum.
AB - The objective of this study was to characterise a recombinant antigen of
Ancylostoma caninum that had been identified by immunoscreening with selected
antisera described elsewhere. In vitro expression of clone 341 produced a protein
with an apparent molecular mass of approximately 34 kDa which was recognised in
Western blots by antisera against whole worms and antisera against esophagi from
adult worms, but not by sera from experimentally infected dogs or rabbits. DNA
sequencing showed a cDNA of 1176 bp coding for a 34-kDa protein, similar to the
size identified in the immunoblot. DNA database comparison revealed an 80-82%
homology with the Caenorhabditis elegans unc-15 gene coding for paramyosin. The
deduced aa sequence of clone 341 showed 95% homology with the paramyosin aa
sequence of C. elegans. Affinity purified antibodies against the recombinant
protein recognise a protein with an apparent molecular mass of 97 kDa of A.
caninum muscle tissue fraction which is in accordance with the molecular mass of
paramyosin from Schistosoma mansoni and Schistosoma japonicum.
PMID- 9762570
TI - Use of P-glycoprotein gene probes to investigate anthelmintic resistance in
Haemonchus contortus and comparison with Onchocerca volvulus.
AB - A P-glycoprotein gene probe from the sheep parasitic nematode Haemonchus
contortus was developed and used to analyse restriction fragment length
polymorphisms between susceptible isolates and isolates resistant to either
benzimidazole; levamisole and benzimidazole; or benzimidazole, ivermectin and
closantel. No polymorphism could be correlated with any of the different
resistances. A P-glycoprotein gene probe was also isolated from the human
nematode parasite Onchocerca volvulus and an Onchocerca-specific PCR was
developed.
PMID- 9762571
TI - The phylogenetic position of Udonella (Platyhelminthes).
AB - Phylogenetic analysis of molecular data from complete 18S rRNA and partial 28S
rRNA genes, of a variety of platyhelminths, places the enigmatic Udonella
caligorum firmly as a monopisthocotylean monogenean. Both maximum parsimony and a
modified distance measure, operating under a maximum likelihood model, gave
identical solutions for each data set. These data further support morphological
evidence from ultrastructural studies indicating the neodermatan affinities of
Udonella, namely shared features in sensory receptors, surface tegument, sperm
structure and spermiogenesis. The molecular data reject the class Udonellidea and
the placement of udonellids as sister-group to the Neodermata. As shown
previously with molecular data, the monogeneans appear as a paraphyletic
assemblage comprising strongly monophyletic Monopisthocotylea and
Polyopisthocotylea. Their relationships with the trematodes and cestodes are not
resolved with 28S rDNA or 18S rDNA alone.
PMID- 9762572
TI - A comparison of the first internal transcribed spacer of ribosomal DNA in seven
species of Trichostrongylus (Nematoda: Trichostrongylidae).
AB - The first internal transcribed spacer (ITS-1) of the ribosomal DNA of seven
species of Trichostrongylus was sequenced. The length of ITS-1 in the different
species varied from 387 to 390 bases. The G + C content of the ITS-1 sequences
were approximately 42%. Little or no intraspecific variation was detected in the
three species. Trichostrongylus axei, Trichostrongylus colubriformis and
Trichostrongylus vitrinus, for which multiple isolates from different
geographical regions were sequenced. In contrast, the level of ITS-1 sequence
differences between species ranged from 1.3% to 5.7%. The greatest sequence
differences were detected between T. tenuis, the parasite species which infects
birds and the six species found in mammals. Some of the nucleotide differences
occurred at sites corresponding to recognition sites for restriction
endonucleases. These results are compared with previous data obtained for the
second internal transcribed spacer (ITS-2). The ITS-1 data indicate that this
region of rDNA may also be useful for systematic studies in trichostrongylid
nematodes.
PMID- 9762573
TI - Phylogeny of benign Theileria species from cattle in Thailand, China and the
U.S.A. based on the major piroplasm surface protein and small subunit ribosomal
RNA genes.
AB - The major piroplasm surface protein and small subunit ribosomal RNA genes of
benign Theileria species isolated from cattle in China, Thailand and the U.S.A.
were amplified by polymerase chain reaction, cloned and sequenced. The major
piroplasm surface protein genes of these three isolates were more than 89%
identical at amino-acid level. Several deletions in the gene from the Thai
isolate led to considerable structural change through frame shifts of the major
piroplasm surface protein. Phylogenetic analyses based on both of the major
piroplasm surface protein and small subunit ribosomal RNA genes suggest that
there may be a second cosmopolitan benign Theileria species infecting cattle in
addition to the Theileria sergenti/buffeli/orientalis complex.
PMID- 9762574
TI - Protein supplementation improves the performance of parasitised sheep fed a straw
based diet.
AB - A study was made of the benefits of protein supplementation for parasitised and
non-parasitised lambs. Sixty, 5-month-old crossbred wether lambs were placed in
individual pens indoors for 9 weeks. Half of the animals were experimentally
dosed with 1500 Haemonchus contortus larvae per head per week and were fed ad
libitum and the other half were worm-free, pair-fed controls. Diets were
formulated to be iso-energetic (9.0 MJ of calculated metabolisable energy per kg
dry matter) with five levels of protein (10, 13, 16, 19 and 22% crude protein).
These diets were based on oaten chaff, with barley, cotton-seed meal, urea and
mineral mix (except for the 22% crude protein diet which did not contain barley).
Dietary crude protein content increased live-weight gain, feed intake, rumen
fluid ammonia-N, packed cell volume, eosinophil counts and antibody responses to
H. contortus L3 antigen and decreased faecal worm egg counts significantly.
Infection did not significantly affect packed cell volume of animals on diets
with 16, 19 and 22% crude protein content. We conclude that extra dietary protein
can prevent the adverse effects of H. contortus infection on animal production.
PMID- 9762575
TI - In vitro antifilarial activity of organometallic complexes against infective
larvae of Molinema dessetae and adult females of Brugia pahangi.
AB - New organometallic complexes having protozoocidal properties were evaluated for
their in vitro antifilarial activity using two models: infective larvae of
Molinema dessetae and adult females of Brugia pahangi. The compound most active
on the M. dessetae model was Ir(I)-COD-pentamidine tetraphenylborate with an EC50
= 6 +/- 1 microM after 7-day-incubation. In the 2-aminobenzothiazole series,
Ruthenium was more potent than Iridium for antifilarial activity. A
dithiocarbamate function significantly enhanced the antifilarial activity. The
compounds derived from benzimidazole were inactive whatever the metal (Iridium or
Rhodium). The other compounds exhibited EC50 ranging from 10 to 31 microM. On
adult female Brugia pahangi in vitro, Pt-DDH-N-acetylleucine, Pt-diminazene and
Pd-Cl4-piperazine at 20 microM began to kill both microfilariae and the
developing embryos within the mothers on day 2. The compounds, except for Pd-Cl4
piperazine, killed the adults after 5 days. Rh-Cl-2-chloropyridine caused obvious
slowing of the adults from day 3 onward but did not affect the viability of
adults, microfilariae or developing embryos. In vivo antifilarial investigations
are necessary to appreciate the real advantage of heavy metal complexes in the
experimental treatment of filariasis.
PMID- 9762576
TI - Rodent malaria prophylaxis by transdermal delivery of primaquine.
AB - The efficacy of a new transdermal delivery system of primaquine in order to
obtain causal prophylaxis against sporozoite-induced Plasmodium yoelii infection
was evaluated. A single administration of a 1.0 cm2 transdermal delivery system
containing 5.0 mg of primaquine was able to protect 100% of treated mice. This
result suggests that the transdermal route may be a very interesting approach for
malaria prophylaxis and should encourage further studies in order to determine
the absolute bioavailability of the drug as well as its dose-effect relationship.
PMID- 9762577
TI - Seasonal variation of gastrointestinal nematodes of sheep in the region of
Joannina, Greece.
AB - Parasitological and growth studies on two groups of naturally infected sheep,
with or without anthelmintic treatment, from the age of 3 months to 2 years were
carried out in the region of Joannina, Greece. A split-plot design was used so
that each group, consisting of seven pure-bred Boutsiko and seven cross-bred
Boutsiko with Karamaniko (F1) lambs, grazed separate parasitologically equivalent
pasture plots. Faecal egg counts, pasture larval counts, plasma pepsinogen levels
and live weight were recorded monthly. Infective larvae on each pasture plot
increased during autumn and winter. Mean faecal egg counts for strongyle-type
eggs were higher in the non-treated than the treated group and in the cross than
the pure-bred sheep. Mean plasma pepsinogen levels were higher during autumn of
the second year of the study. The results of the study suggest that the factors
affecting the epidemiology of gastrointestinal nematodes of naturally infected
sheep during grazing in the region of Joannina include anthelmintic treatment,
host genotype and season, while the effectiveness of anthelmintic treatment in
this study, as applied in the area, was questionable.
PMID- 9762578
TI - Canine neosporosis: clinical signs, diagnosis, treatment and isolation of
Neospora caninum in mice and cell culture.
AB - Clinical signs, diagnosis, treatment and isolation of Neospora caninum from two
littermate dogs are described. Three of six pups from a Labrador bitch developed
paralysis. Neosporosis was diagnosed ante mortem by serological examination in
two of the affected pups. At necropsy, tissue cysts were seen in unstained smears
and in histologic sections of their brains. Tissue cysts were often thin-walled
(approximately 1 micron) but antigenically and ultrastructurally identified as N.
caninum. Furthermore, N. caninum (isolates NC-4, NC-5) was isolated in mice and
in cell cultures inoculated with neural tissues of these two dogs. Serological
diagnosis of neosporosis using a variety of tests is discussed.
PMID- 9762579
TI - Monoclonal antibodies to Toxoplasma gondii strain 119 identify recently isolated
Danish strains as one group.
AB - Four mAb raised against the Danish Toxoplasma gondii strain 119, were selected by
screening hybridoma supernatants by indirect immunofluorescence against
tachyzoites of the RH strain in order to obtain strain-restricted markers. Strain
restriction extended beyond discrimination of the 119 and RH strains, as
demonstrated on a further six T. gondii reference strains [BK and GT1 (group A),
NTE and 561 (group B), and NED and C56 (group C)]. The bradyzoite-specific mAb,
4.3, reacted to the GT1, NTE and 561 strains, but not to the BK, NED or C56
strains. The tachyzoite-specific mAb, 4.25, reacted to all strains tested except
the RH strain, while mAb 5.1 reacted to tachyzoites of strains NTE and 561, but
not to those of the BK, GT1, NED or C56 strains. Monoclonal antibody 5.15 reacted
with the same strain restriction as monoclonal antibody 5.1, but to bradyzoites
as well as tachyzoites. A T. gondii strain collection representative for a small
geographic area (Denmark) was established within a short time span from a variety
of animal species. Using the mAb as typing reagents to this Danish strain
collection, all 36 animal and two human strains were identified as having the
same reaction pattern as strains 119, NTE and 561.
PMID- 9762580
TI - Prenatal protein restriction alters synaptic mechanisms of callosal connections
in the rat visual cortex.
AB - Mild prenatal protein malnutrition, induced by reduction of the casein content of
the maternal diet from 25 to 8%, calorically compensated by the addition of
excess carbohydrates, leads to so-called "hidden" malnutrition in the rat. This
form of malnutrition results in normal body and brain weights of pups at birth,
but in significant alterations of their central nervous system neurochemical
profiles. Since severe forms of prenatal malnutrition induce morpho-functional
deficits on callosal interhemispheric communication together with brain
neurochemical disturbances, we evaluated, in rats born from mothers submitted to
an 8% casein diet, the potassium-induced release of [3H]-noradrenaline in visual
cortex slices, as well as functional properties of callosal-cortical synapses by
determining cerebral cortical excitability to callosal inputs and fatigability
and temporal summation of transcallosal evoked responses. Rats born from mothers
submitted to a 25% casein diet served as controls. At birth prenatally
malnourished pups had significantly higher cortical percent net noradrenaline
release (14.79 +/- 1.11) than controls (9.14 +/- 1.26). At 45-50 days of age,
rehabilitated previously malnourished rats showed, when compared to controls; (i)
significantly reduced percent net noradrenaline release in the visual cortex
(4.50 +/- 0.52 vs 11.31 +/- 1.14); (ii) decreased cortical excitability to
callosal inputs as revealed by significantly increased chronaxie (607.2 +/- 82.8
microseconds vs 351.3 +/- 47.7 microseconds); (iii) enhanced fatigability of
transcallosal evoked responses as revealed by significantly decreased stimulus
frequency required to fatigate the responses (4.9 +/- 0.8 Hz vs 9.2 +/- 1.3 Hz);
and (iv) decreased ability of callosal-cortical synapses to perform temporal
summation, as revealed by significantly reduced percent response increment to
double-shock (54.2 +/- 6.2 vs 83.0 +/- 11.0, for a 3.2-ms interstimulus time
interval). These changes, resulting from mild prenatal protein restriction, are
discussed in relationship to developmental processes leading to the formation of
synaptic contacts between callosal axons and their appropriate cortical target
during perinatal age.
PMID- 9762581
TI - Morphological and morphometrical changes in dorsal root ganglion neurons
innervating the regenerated lizard tail.
AB - The variations occurring in neurons from dorsal root ganglia that provide
innervation to the regenerated tail of the lizard (vicarious ganglia) are
analysed. Vicarious ganglion neurons, when compared to control ganglion neurons
(i.e. ganglia from the same animal that were not involved in the reinnervation
process), show a size increase of the soma (cell hypertrophy) which applies to
all cell types and subtypes. No statistically significant differences in the
relative percentage of neurofilament-poor (type D) and neurofilament-rich (type
L) neurons were found between vicarious dorsal root ganglia compared to controls
in all animals. On the contrary, within L neuron sub-types, a statistically
significant increase in sub-type L2 (very rich in neurofilaments), and the
appearance of sub-type L3 neuron which is not detectable in controls, were
demonstrated in vicarious dorsal root ganglia. In spite of these variations in
size and percentage distribution, no structural and ultrastructural differences
of the various cell types and sub-types are detectable, except for the appearance
of the sub-type L3 neurons. However, this neuron sub-type might not be considered
specific of hypertrophy since the same morphological features have been observed,
in normal conditions, in lizard dorsal root ganglia from cervical and lumbar
spinal levels that provide innervation to limb plexuses.
PMID- 9762582
TI - Endogenous modulators of brain Na+,K(+)-ATPase at early postnatal stages of rat
development.
AB - The presence of endogenous modulators (peaks I and II) of synaptosomal Na+, K(+)
ATPase activity from adult rat cerebral cortex was previously suggested. In this
study, the presence of such modulators at different postnatal stages of rat
development was examined and their effect was tested on Na+, K(+)-ATPase
activity. Synaptosomal membrane Na+, K(+)-ATPase activity was enhanced 20-30% by
peak I and inhibited 70-75% by peak II obtained from 4-, 10-, 20- and 35-40-day
old rats. A fraction purified from peak II by anionic exchange HPLC (termed II-E)
highly inhibits enzyme activity and behaves as a ouabain-like factor. Inhibitory
activity of a 4-day-old II-E fraction proved higher than the corresponding
fraction obtained from adult rats. Since expression of cerebral Na+, K(+)-ATPase
has been shown to increase 10-fold during development whereas peak II
concentration was observed to remain constant, and given the higher potency of
purified neonatal II-E fraction, the effect of the latter may be greater at early
postnatal stages of development than during adult life. It is suggested that the
II-E fraction, which contains an ouabain-like factor, may play a role in neuronal
development.
PMID- 9762583
TI - Arachidonate transport through the blood-retina and blood-brain barrier of the
rat after reperfusion of varying duration following complete cerebral ischemia.
AB - The permeability-surface area product (PS) of [1-14C]arachidonate at the blood
retina and blood-brain barrier was determined by short carotid perfusion in young
Wistar rats 1 or 6 h after recovery period following complete cerebral ischemia
induced by temporary cardiac arrest. For the retina and structures of visual
system, hypothalamus and olfactory bulb there was no significant difference over
sham-operated rats among mean PSs. For cortex, hippocampus and striatum,
significant increases were found at both time intervals of recovery after cardiac
arrest. The ischemia-reperfusion model was characterized by a significant
increase in tissue conjugated diene in the hippocampus and microsomal
lysophosphatidylcholine acyltransferase activity in the cortex. Consistent with
these findings, we also show ultrastructural evidence mainly represented by
partial opening of interendothelial junctions and mild signs of tissue edema in
surrounding neuropil, suggesting barrier leakiness predominantly in the cortex,
hippocampus and striatum but almost absent in the retina microvessels. Our
results indicate that ischemia-reperfusion does affect influex through blood
brain barrier into regional structures of rat central nervous system of
arachidonate, a metabolic substrate and lipid mediator rapidly incorporated into
microcapillary and brain lipids. The data also suggested that: (i) reactive
oxyradicals were moderately generated during the early phase of ischemic
reperfusion process in the rat; (ii) after reperfusion, in vitro susceptibility
of different brain regions to iron-induced peroxidation was highest in the
hippocampus and lowest in the cortex and striatum; (iii) membrane phospholipid
repair mechanisms were activated at the same time.
PMID- 9762584
TI - Differences in myelination between spinal cord and corticular tissue transplanted
intraocularly in rats.
AB - This paper compares the myelination in rat cortex and spinal cord transplanted on
the embryonic day (E) 12, 14, 16, 18, 20 and right after birth (P0) into the
anterior eye chamber of adult rats. Myelinated fibers were not observed in either
cortical or spinal cord transplants of E12. When transplanted on E14, abundant
myelinated fibers developed in the spinal cord and gathered at the periphery of
the transplants as a "white matter". In the grafted cortex myelinated fibers were
found when transplantation occurred on E16 or later. The myelinated fibers,
however, remained scarce or formed only narrow bundles. The number and
distribution of myelinated fibers did not depend on the donor's age between E16
and P0: even in the latter case transplanted cortex were found without
myelination. The differences could be attributed to the different development of
the cortical and spinal cord oligodendrocytes and to the different intrinsic
organization of the grafted samples.
PMID- 9762585
TI - Developmental regulation of mouse brain monomeric acetylcholinesterase.
AB - Acetylcholinesterase (AChE) molecular forms were studied during mouse brain
development. Mouse embryos expressed a monomeric (G1) and a tetrameric (G4) AChE
form. Our results indicate that G4 AChE expressed at embryonic day (ED) 9 and
ED15 could be purified by acridinium-Sepharose chromatography and shared similar
biochemical and kinetic properties with the adult form. However, the G1 form
expressed at either embryonic stage did not bind to acridinium, was not inhibited
by excess substrate, and possessed higher K(m) and lower Vmax values than the
adult G1 form. Two peripheral anionic binding site inhibitors, fasciculin and
propidium, had a significantly lower affinity for the monomeric form at ED9.
Results are discussed in terms of the biological significance of the embryonic G1
form, and its resemblance to the AChE activity found, associated with the senile
plaques present in the brains of Alzheimer's patients.
PMID- 9762587
TI - The real and imagined harmful effects of rewards: implications for clinical
practice.
AB - In recent years, a number of researchers and social critics have cautioned
against the widespread application of behavioral interventions on the grounds
that the philosophy of behaviorism is fundamentally manipulative and damaging to
creative and intrinsically motivated behavior. Most central to their arguments
are concerns about the harmful effects of "extrinsic" rewards. Though concerns
about the allegedly harmful effects of "rewards" on intrinsically motivated
actions may have been partially allayed by a recent meta-analysis, proponents of
the view that intrinsic interest is eroded by the delivery of contingent rewards
will likely continue to attest to the dangers of operant conditioning and its
application to human behavior. The present manuscript addresses the content of
claims about the harmful effects of extrinsic rewards. While consideration is
given to the existing behavior therapy literature and its treatment of "natural"
versus "arbitrary" rewards, some surprising convergences between the views of
self-determination theorists and behavioral practitioners are noted.
PMID- 9762586
TI - Brain-derived neurotrophic factor stimulates neurite outgrowth in a calretinin
enriched neuronal culture system.
AB - A calretinin enriched cell culture system which comprised approximately 40% of
the total neuronal population of the E14 rat embryo was established from the
region of the thalamic eminence (TE), and the effects of several neurotrophins on
the neurite growth of calretinin-immunoreactive (CR-IR) neurons was investigated.
A 4-day treatment of BDNF significantly increased the ratio of CR-IR to
microtubule-associated protein 2-immunoreactive neurons at concentrations between
50 and 250 ng/ml. IGF-I at 100 ng/ml and TGF-alpha at 250 ng/ml also increased
this ratio. None of the neurotrophins examined increased the number of primary
neurites. BDNF did, however, increase the number of secondary neurites. BDNF
treated primary and secondary neurites were also significantly longer than
neurites from neurons in control cultures. IGF-I elicited an increase in primary
neurite length, but did not affect either number or length of secondary neurites.
TGF-alpha had no effect on either number or length of the primary and secondary
neurites. These results indicate that the maturation and development of CR-IR
neurites is specifically affected by BDNF. It is suggested that BDNF increases
the CR concentration above the threshold of detection by immunohistochemistry in
cells and stimulates the sprouting of secondary CR-IR neurites.
PMID- 9762588
TI - Generalized anxiety disorder in dysfunctional families.
AB - The purpose of this study was to investigate the relation between persistent
prolonged dysfunction in parents and the development of Generalized Anxiety
disorder (GAD). Initially, 940 adult subjects from a general practice were
studied. Thirty-two parents aged 24 to 61 yr diagnosed with GAD served as the
experimental group, while 117 healthy normal parents aged 24-66 yr made up the
control group. The rate of dysfunctional families with parents diagnosed with GAD
was significantly higher than in families with parents not diagnosed with GAD.
Family dysfunction was associated with parents' age both in men and in women. GAD
was not connected with (1) parents' age, (2) education, (3) employment, (4)
country of origin or (5) number of children in the family. There was no
significant difference between men and women in onset and duration of GAD.
Implications for diagnostic and treatment issues are discussed.
PMID- 9762589
TI - Emotional response at the time of a potentially traumatizing event and PTSD
symptomatology: a preliminary retrospective analysis of the DSM-IV Criterion A-2.
AB - DSM-IV added an emotional response component to the definition of Criterion A for
PTSD. The present study investigated the relationship between retrospective
reports of emotional responses (fear, helplessness, and horror) and disrupted
emotional responses ("numbing") at the time of a potentially traumatizing event
and reports of PTSD symptomatology among undergraduate participants. We found
that, of the DSM-IV criteria, only helplessness was significantly correlated with
post-traumatic symptomatology. Reports of peritraumatic emotional numbing
uniquely predicted subsequent PTSD symptomatology beyond coincident emotional
responses, suggesting that further research is needed to explore the various
dimensions of peritraumatic emotional response relevant to the development of
PTSD.
PMID- 9762590
TI - Making sense of schizophrenic symptoms; delusional statements and behavior may be
functional in purpose.
AB - The present paper describes the use of a functional analysis in attempting to
make sense of symptomatic delusional statements and behaviors that people
diagnosed with schizophrenia present. The three categories that are used to
classify symptoms are: (1) positive reinforcement function, (2) negative
reinforcement function, and (3) mislabeling of private events. The paper presents
a number of clinical cases whose symptoms are representative of each category.
Each case is then functionally treated as a result of its "category"
characteristics, thus basing treatment on the hypothesized function (or reason)
for the symptom.
PMID- 9762591
TI - A review of behavioral and pharmacological treatments for habit disorders in
individuals with mental retardation.
AB - This paper reviews the prevalence and behavioral and pharmacological treatment
outcome studies for habit disorders exhibited by individuals with mental
retardation. The treatment-outcome studies target the habit disorders identified
previously by researchers including nervous habits (nail biting, bruxism, and
trichotillomania), motor and vocal tics, and Tourette's disorder. The paucity of
behavioral treatments and the lack of controlled pharmacological research
warrants further experimental evaluation of treatments for habit disorders
affecting individuals with mental retardation. Conclusions and recommendations
for future research are made.
PMID- 9762592
TI - The evaluation of heart rate biofeedback using a multi-element design.
AB - This experiment used the integration of a multi-element design with a second
baseline to isolate the effect of biofeedback on the control of a target
response, heart rate. The results of the experiment indicate that contingent
visual heart rate feedback was instrumental in specifically facilitating the
control of heart rate and that control was not mediated by the effects of changes
in overall arousal level as measured by skin conductance. These results encourage
the experimental analysis of biofeedback using single case designs. Further, the
design presented herein offers a clinically and experimentally useful methodology
for biofeedback research.
PMID- 9762593
TI - Behavioral treatment of obsessive-compulsive disorder in African Americans:
clinical issues.
AB - African Americans with obessive-compulsive disorder are underrepresented in
behavioral treatment outcome studies. This paper consists of a clinical
discussion of issues arising during the treatment with exposure plus response
prevention of two African-American women with obessive-compulsive disorder.
Clinical issues, such as excessive shame, insanity fears, and a sense of
uniqueness, complicated the treatment process. However, both clients made
significant improvement as assessed by behavioral testing, target ratings and the
Yale-Brown Obsessive-Compulsive Scale.
PMID- 9762594
TI - Two-phase treatment of panic disorder and posttraumatic stress disorder with
associated personality features resulting from childhood abuse: case study.
AB - The treatment of a women diagnosed with panic disorder with Agoraphobia and
posttraumatic stress disorder and maladaptive personality features resulting from
childhood sexual and physical abuse is described. The treatment consisted of nine
sessions of cognitive behavior therapy (CBT) for Panic Disorder with Agoraphobia
and nine sessions of implosive therapy (IT) for Posttraumatic Stress Disorder.
CBT decreased scores on the clinical scales of the Personality Assessment
Inventory (PAI), but did not reduce revised Impact of Event Scale (IES) scores,
or Dimensional Assessment of Personality Problems-Basic Questionnaire (DAPP-BQ).
IT decreased scores on the IES and the DAPP-BQ, and further reduced scores on the
PAI. The results are discussed with regard to Levis' (1985) implosive theory of
psychopathology, which suggests that psychopathology can be explained by
Pavlovian conditioning of serial cues and instrumentally conditioned avoidance
responses.
PMID- 9762595
TI - Dismantling simplified regulated breathing: a case of a bilingual stutterer.
AB - In this case study of a 28-year-old bilingual male, the Simplified Regulated
Breathing treatment for stuttering was further dismantled. Implementing
noncontingent diaphragmatic breathing in one treatment session, stuttering was
reduced in both English (his second language) and Russian (his native language),
while his words per minute increased. In addition, the implementation of
treatment resulted in a decrease in secondary struggle behaviors associated with
stuttering. The results were seen as socially valid and the treatment was seen as
acceptable to the participant. Implications of this case study are presented.
PMID- 9762596
TI - Neonatal onset in fatty acid oxidation disorders: how can we minimize morbidity
and mortality?
PMID- 9762597
TI - Diagnosis of isovaleric acidaemia by tandem mass spectrometry: false positive
result due to pivaloylcarnitine in a newborn screening programme.
AB - Tandem mass spectrometric analysis of acylcarnitines and amino acids has been
applied in newborn screening programmes for the detection of several inborn
errors of metabolism. We report a false positive result for isovaleric acidaemia
in a newborn screening programme using this method. The newborn screening sample
showed a very prominent signal corresponding to the mass of isovalerylcarnitine.
Repeat samples (age 6 days) of blood and urine showed similar results. However,
urine organic acids were normal. Acylcarnitine analysis in blood, breast milk and
urine of the mother also showed a prominent signal of the same mass. Gas
chromatography-mass spectrometry of the methyl esters demonstrated that the
signal in the patient's urine was due to the presence of pivaloylcarnitine, which
is isomeric with isovalerylcarnitine. The patient's mother was receiving an
antibiotic containing a derivative of pivalic acid to treat a urinary tract
infection. Follow-up samples in the patient and the mother confirmed a decrease
in the levels of pivaloylcarnitine, concomitant with the discontinuation of the
treatment. We conclude that pivaloylcarnitine can give a false positive result
for isovaleric acidaemia in newborns whose mothers are on treatment with
pivoxilsulbactam-containing antibiotics.
PMID- 9762598
TI - Variable clinical presentation in three patients with 3-methylglutaconyl-coenzyme
A hydratase deficiency.
PMID- 9762599
TI - Methylmalonic acidaemia with bilateral globus pallidus involvement: a
neuropathological study.
AB - A 16-month-old boy was hospitalized because of a 1-day history of severe
ketoacidosis with lethargy, hypotonia, vomiting, and important dyspnoea. Organic
acid assay by gas chromatography-mass spectrometry confirmed the diagnosis of
methylmalonic acidaemia (MMA). On the sixteenth day, he developed an acute
extrapyramidal disorder. The CT scan of the brain disclosed bilaterally symmetric
lucency of basal ganglia. He died at 17 months of age. Post-mortem
neuropathological examination, showed severe necrosis with spongiosis, cystic
cavitation and numerous lipid-laden macrophages of the globi pallidi, and mild
spongiosis of subthalamic nuclei, mammillary bodies, portion of internal capsule
adjacent to globus pallidus, superior cerebellar peduncles and tegmentum of
brainstem. Pallidal infarction, a focal ischaemic lesion, demonstrates that
ischaemia/energy depletion may be important in the etiology of the neuropathology
of MMA.
PMID- 9762600
TI - Lactic acidosis in long-chain fatty acid beta-oxidation disorders.
AB - Among the many disorders of fatty acid beta-oxidation known today, the disorders
of long-chain fatty acid oxidation are the most severe and life-threatening. One
remarkable abnormality, not observed in, for instance, medium-chain acyl-CoA
dehydrogenase deficiency, is the moderate to severe lactic acidaemia in long
chain fatty acid beta-oxidation-deficient patients, suggesting that oxidation of
pyruvate is also compromised. In order to understand the underlying basis of the
lactic acidaemia in these patients, we have studied the formation of L-lactate
and pyruvate in cultured skin fibroblasts incubated with D-glucose. All long
chain fatty acid beta-oxidation-deficient cell lines studied were found to show a
moderate elevation of lactate when compared with control and medium-chain acyl
CoA dehydrogenase-deficient fibroblasts. Interestingly, differences were found
between cells deficient in long-chain 3-hydroxyacyl-CoA dehydrogenase and very
long-chain acyl-CoA dehydrogenase, suggesting that saturated acyl-CoA esters and
their 3-hydroxyacyl-CoA derivatives affect pyruvate metabolism differently.
PMID- 9762601
TI - Hunter disease in the Spanish population: molecular analysis in 31 families.
AB - Mucopolysaccharidosis type II (Hunter disease) is an X-linked disorder due to
deficiency of the lysosomal enzyme iduronate 2-sulphatase. Here we report an
update of molecular studies in 31 Spanish families with Hunter disease. We found
a total of 22 novel small mutations (7 reported previously by our group), and 4
large deletions or rearrangements. Particularly relevant are two mutations, one
showing an alternatively spliced product although the normal splice site is
conserved; the other mutation results in an amino acid change that most likely
modifies regulation of expression of the IDS gene. Except for large gene
alterations and for the G374sp mutation already described, we could not establish
a clear phenotype-genotype correlation. Mutation G374sp is the point mutation
most frequent in our population (10%) and is always associated with mild
phenotype. Our molecular analyses carried out in a relatively large series of
patients with Hunter disease contribute to the identification of new mutations
and reinforce the conclusions drawn in other populations about the genotype
phenotype correlation and the gene distribution of mutations.
PMID- 9762602
TI - Generalized peroxisomal disorder in male twins: fatty acid composition of serum
lipids and response to n-3 fatty acids.
AB - Male, identical twins presented with hypotonia, hypoglycaemia, dysmorphic facies,
feeding problems, discoloured stools, hepatomegaly, and nephrolithiasis. Elevated
blood levels of very long-chain fatty acids and bile acids suggested a
peroxisomal disorder. Plasmalogen biosynthesis in cultured fibroblasts was
reduced. Morphologically distinct peroxisomes were undetectable in liver. Twin 1
suffered from nephrocalcinosis and severe infection, and died at 18 months of
age. Twin 2 was blind and physically severely retarded with epilepsy, but
survived up to the age of 5 years. Studies of the fatty acid composition of serum
lipids showed barely detectable values of eicosapentaenoic (EPA) and
docosahexaenoic acid (DHA). During long-term treatment with these n-3 fatty
acids, started at age 10 months, the fatty acid profile of the serum lipids was
improved or normalized. Since n-3 fatty acids are essential elements in normal
development, notably of the nervous system, we suggest that treatment with EPA
and DHA should be started as early as possible in general peroxisomal disorders.
PMID- 9762603
TI - Hyperinsulinism and hyperammonaemia.
PMID- 9762605
TI - Complications of lysinuric protein intolerance must be treated with
immunosuppressive drugs.
PMID- 9762604
TI - Neonatal medium-chain acyl-CoA dehydrogenase deficiency presenting with very high
creatine kinase levels.
PMID- 9762606
TI - Adult-onset arginase deficiency.
PMID- 9762608
TI - Recurrent nonimmune hydrops fetalis associated with carbohydrate-deficient
glycoprotein syndrome.
PMID- 9762607
TI - Anaemia and thrombocytopenia due to haemophagocytosis in a 7-month-old boy with
galactosialidosis.
PMID- 9762609
TI - 3-Methylglutaconic aciduria associated with hepatosplenomegaly, macrocytic
anaemia, fever episodes, recurrent infections, cervical lymphadenopathy and
progressive decrease of physical performance.
PMID- 9762610
TI - A family with Leigh syndrome caused by the rarer T8993C mutation.
PMID- 9762611
TI - Succinyl-CoA:acetoacetate transferase deficiency. Identification of a new case;
prenatal exclusion in three further pregnancies.
PMID- 9762612
TI - A fucosidosis patient with relative longevity and a missense mutation in exon 7
of the alpha-fucosidase gene.
PMID- 9762614
TI - In vivo methods useful for therapy monitoring in lactic acidosis.
PMID- 9762613
TI - Homocystinuria (methylenetetrahydrofolate reductase deficiency) and mutation of
factor V gene.
PMID- 9762616
TI - MS-PCR assay to detect 677C-->T mutation in the 5,10-methylenetetrahydrofolate
reductase gene.
PMID- 9762615
TI - Medium-chain acyl-CoA dehydrogenase deficiency in Spain.
PMID- 9762617
TI - The NHS is 50: the first 25 years.
PMID- 9762618
TI - A physician's reflections on 50 years of the NHS.
PMID- 9762619
TI - The development of public health medicine.
PMID- 9762620
TI - The NHS: the next 50 years.
PMID- 9762621
TI - Emerging viral diseases.
PMID- 9762622
TI - Tuberculosis: an international perspective.
PMID- 9762623
TI - Drug resistant tuberculosis in adults and its treatment.
PMID- 9762624
TI - Meningitis and meningococcal septicaemia.
PMID- 9762626
TI - Wasted words.
PMID- 9762627
TI - Genetic counselling and testing in Europe.
AB - The Genetic Enquiry Centre in Manchester has designed a three-pronged health
services research programme to address current issues in genetics. The issues
are: whether doctors who are not trained in genetics can manage the genetic
problems they meet in their practice; whether there are enough resources in
specialist centres to cope with current and imminent referrals; and whether
providers of primary care recognise genetic problems and refer patients
appropriately. The three studies providing the basis of the programme--the
National Confidential Enquiry into Counselling for Genetic Disorders, the
Concerted Action on Genetics Services in Europe and the Primary Care for Genetics
Patients study--are discussed. The first two provide unique views of genetic
counselling in the UK and of the access to and quality of health services for
patients with or at risk of genetic disorders throughout Europe, and make
recommendations based on their findings. The third is a continuing study that
aims to determine the effects of patterns of referral and care in the different
healthcare systems in Europe. Although it is unlikely that there will ever be
enough medical geneticists to cope with the consequences of genetic advances on
health services that are largely unprepared, specialist genetic centres are the
natural core resource for future multi-specialty genetic services. This will give
clinical geneticists an extended role complementary to that of diagnosing rare
syndromes.
PMID- 9762625
TI - Community acquired pneumonia.
AB - CAP affects all ages but predominantly the elderly. The microbial aetiology is
diverse and rarely established at the time of admission. Initial management
includes assessment of severity, correction of dehydration and imbalances of gas
exchange, and prompt administration of antibiotic. The regimens will vary by risk
factor and severity assessment. Mortality remains high, especially in those
requiring intensive care. Prevention includes control of underlying disease,
smoking and ethanol abuse, and the appropriate use of influenza and pneumococcal
vaccines.
PMID- 9762628
TI - Reducing waiting times in lung cancer.
AB - BACKGROUND: Concern exists over delays in the management of lung cancer patients.
Maximum waiting times and a multidisciplinary team (MDT) approach have been
recommended in several recent national reports. OBJECTIVE: Having implemented a
MDT approach, we wished to assess whether national recommendations were
achievable and to identify the major factors causing delays. METHODS: Prospective
survey over five months of all new referrals with suspected lung cancer,
documenting waiting times at all stages from referral to definitive treatment.
RESULTS: Of the total of 92 patients, 57 were outpatients (67% seen within one
week, 89% within two weeks of receipt of referral) and 35 were inpatients (all
seen within two working days). Patient age did not influence waiting times to
first being seen or to investigation. The result of the initial diagnostic test
was received within two weeks of first being seen in 86% of patients. All
patients received definitive treatment within recommended times from diagnosis.
Delays in the early part of the care pathway were largely due to potentially
remediable service factors, but unavoidable patient related factors were
important in some prolonged diagnostic delays. CONCLUSIONS: National
recommendations on waiting times are achievable in a high proportion of cases.
The probable importance of the MDT approach is discussed.
PMID- 9762629
TI - Comparison of the views of junior doctors, consultants and managers on work and
training.
AB - OBJECTIVE: To determine the views of junior hospital doctors on their working
conditions, NHS reforms and training, and to compare their views with those of
consultants and managers. SUBJECTS: A questionnaire was distributed to 52 junior
doctors, 19 consultants and 14 middle or senior grade managers in an acute NHS
trust. CONCLUSIONS: Junior doctors had strong feelings about several areas
covered in the questionnaire; in particular, more structured training without the
requirement to undertake a higher degree would be welcomed. Shift systems are
unpopular and the reduction of 'non-medical' tasks with a reduction in work
intensity is perceived to be more important than further reductions in hours
available for work.
PMID- 9762630
TI - Do general practitioners know when living wills are legal?
AB - BACKGROUND: There is growing public awareness of living wills or advance
directives. Patients who wish to make advance directives may approach general
practitioners (GPs) for advice. However, many GPs are unaware of the correct
legal status of living wills. METHODS: Questionnaires were sent to 270 GPs in
London and Winchester, asking seven questions about the current legal status of
living wills. RESULTS: Of the 214 GPs (79%) who returned questionnaires, only 104
(49%) were aware that some types of advance directives could carry legal force.
Many of the GPs who did know that living wills could be legally binding were
unable correctly to answer further questions on the practicalities of the law;
for example, 26% were wrong in believing that a lawyer had to draw up a living
will, and 13% incorrectly believed that a doctor was legally required to give any
treatment requested by a patient in a living will. CONCLUSIONS: Half of the GPs
surveyed were unaware that living wills currently have legal force and most of
the rest were unaware of important details of the law. More attention needs to be
given to the education of doctors in this area.
PMID- 9762631
TI - Successful medical treatment of peptic pyloric stenosis: Dr Sippy revisited.
AB - BACKGROUND: Surgery and balloon dilatation are perceived by many as the principal
treatments for peptic pyloric stenosis. We questioned whether, with the
availability of modern acid suppressant treatment, this was still appropriate or
whether patients could be managed with medical treatment alone. METHODS:
Seventeen consecutive patients with peptic pyloric stenosis were treated with
endoscopic gastric drainage, followed by oral omeprazole in 15 or cimetidine in
two. Gastric emptying half times for solids and liquids were assessed in 11 of
the 17 patients when they had become asymptomatic. RESULTS: Endoscopic drainage
and medical treatment successfully relieved symptoms in all 17 patients, although
the gastric emptying studies in 11 patients still showed prolongation in eight.
Symptoms resolved completely after a mean of 28 days. Five patients relapsed when
changed from omeprazole to cimetidine treatment, but all responded to re-starting
omeprazole. Four patients remain well on cimetidine alone. CONCLUSIONS: Medical
treatment preceded by endoscopic gastric drainage was effective in all patients
in this series and may be the preferred choice of treatment in patients with
pyloric stenosis.
PMID- 9762632
TI - Prescribing alcohol in a general hospital: 'not everything in black and white
makes sense'.
AB - The policies and practicalities of prescribing alcohol for inpatients at a
teaching hospital were examined. Sources of information easily available to
hospital medical staff were searched for guidance on the prescription of alcohol.
No guidance relevant to clinical practice was found. Current practice in a single
hospital was examined using a semistructured staff interview. While nurses and
doctors suggested a wide range of indications for prescribing alcohol, most of
these are not supported by evidence and for some, such as alcoholism and
depression, alcohol would be contra-indicated. The persistence of alcohol
prescribing in hospital is based on tradition rather than evidence of its
effectiveness. It sends an undesirable message to patients who may be suffering
from alcohol-related medical disorders, and it is time to discontinue this
outdated clinical practice.
PMID- 9762633
TI - The enigma of autonomic failure in diabetes.
AB - The extent of autonomic failure in diabetes and the damage that results both in
terms of structure and function is seldom realised. This article focuses on the
consequences of autonomic denervation of several different forms of smooth
muscle, notably those of arterial wall, vas deferens, stomach, iris and bronchial
wall. The clinical implications of these changes are described, in particular the
problems arising from vascular (and vas deferens) calcification and abnormalities
of vascular reactivity; insulin-induced postural hypotension and the splanchnic
circulation; the anaemia of autonomic neuropathy from failure of erythropoietin
production; gastromyopathy as a cause of gastroparesis; iritis as a symptom
related to diabetic autonomic neuropathy (DAN); the concept of an autoimmune
basis for DAN; and failure of bronchial reactivity and respiratory arrests in
DAN. The importance of clinical observation leading to clinical experiment and
research, together with the stimulation of ideas by collaboration with clinical
colleagues in other disciplines is emphasised throughout.
PMID- 9762634
TI - The end of medical history?
PMID- 9762635
TI - Shared care in HIV and AIDS: shifting care or shifting costs?
PMID- 9762636
TI - Medical problems in obstetric practice.
PMID- 9762637
TI - A European exchange scheme.
PMID- 9762638
TI - Evidence-based medicine.
PMID- 9762639
TI - The future of general medicine.
PMID- 9762640
TI - Increased illness experience preceding chronic fatigue syndrome.
PMID- 9762641
TI - Fail-safe screening programme.
PMID- 9762642
TI - Emerging infectious diseases': meeting the challenge. Introduction.
PMID- 9762643
TI - The future of infectious diseases.
PMID- 9762644
TI - Emerging and resurgent pathogens in New York City.
PMID- 9762645
TI - The evolution of virulence and emerging diseases.
AB - Insights into the evolution of virulence may aid efforts to control or even
prevent emerging diseases. Specifically, dangerous pathogens can be distinguished
from those that pose relatively little threat by identifying characteristics that
favor intense exploitation of hosts by pathogens, hence causing high virulence.
Studies to date have implicated several such characteristics, including
transmission by vectors, attendants, water, and durable propagules. These
insights may improve the return on investments in disease control by directing
effort and resources to the most-dangerous emerging pathogens. The approach also
should help us to identify those control measures that will guard against the
future emergence of dangerous pathogens, even those that have not yet been
identified.
PMID- 9762647
TI - Overview: surveillance and sentinel systems.
PMID- 9762646
TI - Social, behavioral, and demographic factors in emerging infections.
PMID- 9762648
TI - Household-related variables and reported illness in street vendors and their
children in a South African city.
PMID- 9762649
TI - Mortality in Hartford, Connecticut: a comparison with the South Bronx, New York.
AB - Very high mortality rates have been reported in large inner-city areas such as
the South Bronx and Harlem in New York City, but also may occur in smaller US
urban areas. Using published death rates for the South Bronx as the standard, the
standardized mortality ratio was slightly lower than 1.00 for Hartford,
Connecticut (population 139,739 in 1990), but more than 1.00 for three
impoverished Hartford census tracts that contained public housing projects.
Compared with the South Bronx, death rates in Hartford were lower for human
immunodeficiency virus (HIV), injury-homicide, and alcohol-drugs, but higher for
hypertension-stroke (in all three tracts) and cancer (in two of the three
tracts). Variations in patterns of causes of death among impoverished US urban
areas have implications for planning epidemiologic studies and targeting
interventions.
PMID- 9762650
TI - Addiction treatment: promoting a medical approach to substance use.
PMID- 9762652
TI - Commentary on "Active immunization against poliomyelitis".
PMID- 9762651
TI - Active immunization against poliomyelitis. April 2, 1953.
PMID- 9762653
TI - Decreasing cryptosporidiosis among HIV-infected persons in New York City, 1995
1997.
PMID- 9762654
TI - Neuropathology in multiple sclerosis: new concepts.
AB - Multiple sclerosis lesions are characterized by inflammation, demyelination and a
variable degree of axonal loss. The patterns of inflammation in MS lesions are
compatible with a T-lymphocyte mediated immune reaction. The formation of
demyelinated plaques, however, seem to require additional immunological
mechanisms. In this review evidence is discussed for a pathogenetic role of
demyelinating antibodies, toxic macrophage products, cytotoxic T-cells as well as
metabolic disturbances of oligodendrocytes. It is suggested that the pathological
heterogeneity regarding the patterns and extent of demyelination, remyelination
and axonal loss may be the outcome of variable dominant immunopathogenetic
mechanisms in different multiple sclerosis patients.
PMID- 9762655
TI - Cerebrospinal fluid--physiology, analysis and interpretation of protein patterns
for diagnosis of neurological diseases.
AB - The state of the art in routine CSF analysis is reviewed with particular
reference to multiple sclerosis regarding: (1) The physiology and pathophysiology
of blood-CSF barrier function and dysfunction with the CSF flow rate as main
modulator of blood- and brain-derived protein concentrations in CSF; (2) The
neuroimmunological aspects regarding (a) patterns of disease-related
immunoglobulin class response (IgG, IgA, IgM) in actual Reiber graphs with
reference to specific parameters and optional tests, and (b) the oligoclonal,
polyspecific antibody synthesis in brain; (3) Particular marker proteins in CSF
and blood for differential diagnosis of neurological diseases; (4) Mathematical
base for evaluations of CSF data with an example of a multiple sclerosis patient
for calculation of intrathecal immunoglobulin and antibody synthesis as well as
Antibody Index.
PMID- 9762656
TI - Composite cerebrospinal fluid score in relapsing-remitting and secondary
progressive multiple sclerosis.
AB - We investigated whether cerebrospinal fluid (CSF) analysis may differentiate
between relapsing-remitting (RR) and secondary progressive (SP) multiple
sclerosis (MS). In 17 RR and 16 SP patients we determined: albumine CSF/PB ratio;
mononuclear cell (MNC) number, CD4+, CD8+, and B1+ subsets, CD4+/CD8+ ratio; IgG,
IgG index, IgM, IgM index, complement components C3 and C4, and C3 and C4
indexes; myelin basic protein; neuron-specific enolase (NSE); S100; and lactate.
For each parameter the statistical distance was calculated. Then, using linear
discriminant analysis, we computed a discriminant score, including only variables
with a P value less than or equal to 0.15: albumin CSF/PB ratio, MNC number, IgM,
IgM index, C3, C4, NSE, S100, and lactate. The discriminant score allocated all
17 RR patients to the RR group and 15 of 16 SP patients to the SP group. We
conclude that RR and SP MS patients differ with respect to CSF profile and that
in individual patients a composite CSF score may differentiate between RR and SP
MS.
PMID- 9762657
TI - The intrathecal, polyspecific and oligoclonal immune response in multiple
sclerosis.
AB - We report an extended set of neuroimmunological data detected in cerebrospinal
fluid (CSF) from n = 267 patients with definite multiple sclerosis (MS). Known
frequencies of oligoclonal IgG (98%), frequencies of intrathecal fractions of
IgG, IgA and IgM (72%, 9% and 20%, respectively) were confirmed and quantitated
as intrathecal fractions, IgIF or CSF concentrations, IgLOC. Eighty-nine per cent
of the patients had a combined 'MRZ-reaction', i.e. intrathecal antibody
synthesis (Antibody Index, AI > 1.4) against measles, rubella and/or varicella
zoster virus. Frequencies of single antibodies decreased from measles (78%) to
rubella (60%), VZV (55%) and HSV (28%). This MRZ-reaction, indicating a chronic
autoimmune type disease already at time of first clinical symptoms, is less
sensitive but more specific than detection of oligoclonal IgG. With increasing
intrathecal IgG synthesis the number of different locally synthesized antibody
species were increased as well as the amount per species (increased mean AI
values). The concentration of MRZ antibodies in CSF represents together about 2%
of intrathecally synthesized total IgG. But, as a very particular result the
ratio of intrathecally synthesized specific antibody/intrathecally synthesized
JgG was 5-fold higher (0.24-0.85%) compared to the corresponding ratio in blood
(0.06-0.17%) of MS patients. This difference between brain ratio and blood ratio
is discussed to be indicative for the anti-MRZ antibody forming B-lymphocyte
subset in blood migrating into brain at earlier time of pathophysiological start
of disease. These results give a concise explanation of neuroimmunological
aspects in MS, not understood so far.
PMID- 9762658
TI - CSF-enriched antibodies do not share specificities among MS patients.
AB - The specificity of the oligoclonal immunoglobulins found in MS CSF is unknown. We
have previously shown that random peptide libraries displayed on phage can be
used to identify specific ligands for CSF antibodies. Here we describe the use of
this tool in the attempt to identify MS-specific CSF-enriched antibody
reactivities with potential pathogenic, diagnostic or prognostic value. Applying
different experimental strategies, several ligands reacting with CSF-enriched
antibodies were identified. When tested against a panel of 55 MS patients, none
of the ligands found were recognized by antibodies shared by any two patients. We
used the selected peptides to demonstrate the stability in time of CSF-enriched
antibodies notwithstanding disease progression.
PMID- 9762659
TI - Myelin basic protein in CSF as indicator of disease activity in multiple
sclerosis.
AB - There is an evident need for a quantitative laboratory marker for ascertaining
disease activity and treatment effects in multiple sclerosis (MS) patients.
Activity of the disease process in MS is accompanied by myelin breakdown and
appearance of myelin basic protein (MBP) in cerebrospinal fluid (CSF). In this
paper MBP in CSF of relapsing-remitting (RR) MS patients is reviewed. MBP in CSF
is a fragment containing an epitope corresponding to amino acid residues 45-89 of
the native molecule. From several relevant studies about CSF MBP in RR MS the
following relations can be concluded: CSF MBP levels in active MS patients are
frequently increased (45-100%), remain increased until 5 to 6 weeks after onset
symptoms and are higher in polysymptomatic exacerbations and correlate with
number of gadolinium-enhanced (Gd) lesions on MRI, severity of relapses, EDSS
score and CSF intrathecal IgM synthesis. After an intravenous methylprednisolone
treatment the increased CSF MBP levels return to normal values and reduction in
CSF MBP is related to reduction in EDSS score, number of Gd lesions and CSF
intrathecal IgM synthesis.
PMID- 9762660
TI - MBP, anti-MBP and anti-PLP antibodies, and intrathecal complement activation in
multiple sclerosis.
AB - Intrathecal immunoglobulin synthesis and activation of the complement cascade
occurs in patients with multiple sclerosis (MS). The present study aimed at
further studying the relation between intrathecal immunoglobulin synthesis and
complement activation. We compared total intrathecal synthesis of IgA, IgG, and
IgM, the number of cells secreting anti-myelin basic protein (MBP) and anti
proteolipid protein (PLP) antibodies of the IgG isotype and intrathecal
activation of the complement cascade in patients with possible onset symptoms of
MS (n = 18) or clinically definite MS (n = 30). Early activation of the
complement cascade correlated with intrathecal synthesis of IgM. Intrathecal IgG,
IgA and IgM synthesis also correlated weakly with the presence of cells secreting
anti-MBP or anti-PLP autoantibodies. Full activation of the complement cascade
did not correlate with any measures of intrathecal antibody synthesis. These
findings suggest a complex relation between different immunoglobulin isotypes and
complement activation which may have similarly complex roles in the pathogenesis
of MS.
PMID- 9762661
TI - Can CSF predict the course of optic neuritis?
AB - To discuss the implications of CSF abnormalities for the course of acute
monosymptomatic optic neuritis (AMON), various CSF markers were analysed in
patients being randomly selected from a population-based cohort. Paired serum and
CSF were obtained within a few weeks from onset of AMON. CSF-restricted
oligoclonal IgG bands, free kappa and free lambda chain bands were observed in
17, 15, and nine of 27 examined patients, respectively. Sixteen patients showed a
polyspecific intrathecal synthesis of oligoclonal IgG antibodies against one or
more viruses. At 1 year follow-up five patients had developed clinically definite
multiple sclerosis (CDMS); all had CSF oligoclonal IgG bands and virus-specific
oligoclonal IgG antibodies at onset. Due to the relative small number studied at
the short-term follow-up, no firm conclusion of the prognostic value of these
analyses could be reached. CSF Myelin Basic Protein-like material was increased
in only two of 29 patients with AMON, but may have potential value in reflecting
disease activity, as the highest values were obtained among patients with CSF
sampled soon after the worst visual acuity was reached, and among patients with
severe visual impairment. In most previous studies of patients with AMON
qualitative and quantitative analyses of CSF IgG had a predictive value for
development of CDMS, but the results are conflicting.
PMID- 9762662
TI - Immune pathogenesis of multiple sclerosis. Brain autoimmune reactivity and its
control by neuronal function.
PMID- 9762663
TI - Are there any body fluid markers of brain atrophy in multiple sclerosis?
AB - The weak correlation between inflammatory activity and disease progression in
patients with multiple sclerosis has shifted the emphasis from inflammatory
monitoring to the investigation of the pathological processes of demyelination,
axonal loss, and gliosis. New magnetic resonance imaging (MRI) techniques that
have been developed to measure these processes appear very promising. This paper
will briefly discuss potential body fluid markers of axonal loss, gliosis and
demyelination, as the pathological substrates of brain atrophy, their function
and the principles behind their future study in patients with multiple sclerosis.
PMID- 9762664
TI - Data on cytokine mRNA expression in CSF and peripheral blood mononuclear cells
from MS patients as detected by PCR.
AB - Reverse transcription polymerase chain reaction (RT-PCR) was used to amplify the
mRNA coding for different cytokines in peripheral blood mononuclear cells (PBMC)
and cerebrospinal fluid (CSF) cells from 18 multiple sclerosis (MS) patients as
compared with 21 other neurological patients. mRNA levels were quantitated by
radioactive hybridization of the PCR products. Expression of tumor necrosis
factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-10 mRNA was
elevated in CSF cells of MS patients. In many MS patients, both proinflammatory
and immunoregulatory cytokine messages were detected in the CSF compartment. Such
immune reactivity of CSF cells, as opposed to PBMC, was not associated with
higher clinical activity of the disease. Expression of the B7.1 accessory
molecule mRNA was similarly investigated. In the CSF, it was detected only in
some clinically active MS cases and in other inflammatory diseases.
PMID- 9762665
TI - Therapy with antibodies against CD40L (CD154) and CD44-variant isoforms reduces
experimental autoimmune encephalomyelitis induced by a proteolipid protein
peptide.
AB - Interactions between mononuclear cells are required for the formation of
inflammatory infiltrates in the CNS and the activation of cellular effector
functions provoking demyelination in MS. Membrane-expressed costimulatory
molecules are crucial to such interactions. We therefore investigated whether two
costimulatory molecules, CD40L (CD154, expressed on activated CD4-possible T
cells) and selected CD44-variant isoforms (expressed on activated CD4-positive T
cells), are targets for immunotherapy in MS. The model of experimental autoimmune
encephalomyelitis (EAE) induced in SJL-mice by immunization with a peptide
derived from the proteolipid protein (PLP139-151) was optimized to address these
questions. A previous observation that anti-CD40L (CD154) monoclonal antibodies
can effectively prevent EAE in this model was confirmed, and extended by
demonstrating that CD40 is expressed by cells of the monocytic lineage
infiltrating the spinal cord. In vivo treatment with antibody against the
standard isoform of CD44 (CD44s or CD44H) did not affect disease burden. In
contrast, combined treatment with antibodies against the isoforms CD44v6, v7 and
v10, which are thought to be involved in inflammatory processes, reduced the
disease burden considerably. In addition, CD44v10-expressing cells were detected
in the spinal cord. These data support the idea that CD40-CD40L interactions form
a target for immunotherapy of MS, and indicate that cells expressing CD44v6, v7
and/or v10-containing isoforms have such potential as well.
PMID- 9762666
TI - T cell receptor V beta 5 and V beta 17 clonal diversity in cerebrospinal fluid
and peripheral blood lymphocytes of multiple sclerosis patients.
AB - To better characterize the cellular immune response taking place in the MS
central nervous system, we investigated the blood and CSF T cell receptor (TCR) V
beta 5 and V beta 17 repertoire in HLA-typed patients with recently diagnosed MS
or other neurological diseases (OND). Using a RT-PCR based technique, we analysed
directly ex vivo the CDR3 size of TCR beta chains utilizing V beta 5 (eight
patients with MS and one with OND) or V beta 17 (eight patients with MS and six
with OND) gene segments on paired blood-CSF samples. Globally, the analysis of V
beta 5-J beta and V beta 17-J beta repertoire showed a less diverse pattern in
the CSF samples than in the corresponding peripheral blood lymphocytes both in MS
and in OND patients. However, we did not detect any recurrent clonal expansion
within the V beta 5+ T cells in MS patients, underlining the potential limits of
V beta 5-based immunotherapy in MS. We found an expanded T cell population using
the same V beta 17-J beta 1.6 combination with identical CDR3 length in the CSF
of three MS patients and none of the control patients. These results suggest
selective expansion of T cells expressing this segment gene in the MS central
nervous system.
PMID- 9762667
TI - Monocyte activation in multiple sclerosis.
AB - Monocytes, macrophages, and microglia have a central role in the CNS inflammation
of MS. Monocytes are important in the earliest events in MS. Peripheral blood
monocytes secrete prostaglandins before MS attacks. During clinical activity
monocyte activation markers increase and IL-1 and TNF-alpha levels are elevated.
Other monocyte products such as IL-10 reduce inflammation. IL-10 mRNA in MNC is
increased during stable disease. Manipulation of monokine secretion and
expression of monocyte surface proteins are reasonable approaches for immune
therapy of MS.
PMID- 9762668
TI - Cytokines in multiple sclerosis: pro-inflammation or pro-remyelination?
AB - The targets of the inflammatory response in multiple sclerosis (MS) are myelin
and the myelin producing cells, oligodendrocytes. The infiltration of activated
immune cells and recruitment of endogenous glia lead to the destruction of myelin
and oligodendrocytes, a process that is compounded by the release of cytokines by
infiltrating cells. Recent evidence suggests that key cytokines that are
responsible for the destruction of myelin may also mediate the process of
remyelination and repair. It appears that both inflammatory and repair processes
are governed by the temporal and spatial relation of cytokines to their targets.
PMID- 9762669
TI - Time-course analysis of CD25 and HLA-DR expression on lymphocytes in interferon
beta 1b-treated multiple sclerosis patients.
AB - To identify immunological markers that could be used to monitor relapsing
remitting multiple sclerosis (RRMS) course/activity during interferon beta 1b
(IFN beta 1b) therapy, we longitudinally studied HLA-DR and CD25 expression by T
lymphocytes in 15 IFN beta 1b-treated RRMS patients. Peripheral blood T cell
subsets were analysed before therapy (T0), and after 1 (T1), 2 (T2), 3 (T3), 6
(T4) and 12 (T5) months after therapy initiation. HLA-DR expression and the
CD3+HLA-DR+ T cell number showed a peculiar trend in almost all (14/15) the
patients: a significant decrease at T1 and T2 followed by a return to pre
treatment levels from T3 to T5. At T1 and T2, eight patients showed an up
regulation of CD25 on CD4, as well as an increase in the CD4+CD25+ cell number.
However, a marked, significant reduction of this T cell subset was observed in
all the patients at T3, followed by the progressive return to pre-treatment
values from T4 to T5. All the patients developed anti-IFN beta 1b 'binding'
antibodies within the first three months of therapy. Our findings demonstrate
that: (1) the expression of HLA-DR and CD25 on T cells, as well as the number of
circulating CD3+HLA-DR+ and CD4+CD25+ cells, are only transiently reduced in vivo
in IFN beta 1b-treated RRMS patients, (2) the expression of HLA-DR and CD25 on T
lymphocytes cannot be used to monitor MS course/activity during IFN beta 1b
therapy, (3) the long-lasting beneficial effect of IFN beta 1b on RRMS reported
in the literature cannot be explained by the down-regulation of MHC class II
antigens and/or interleukin-2 receptor expression induced by this cytokine.
PMID- 9762670
TI - Correlation of soluble adhesion molecules in blood and cerebrospinal fluid with
magnetic resonance imaging activity in patients with multiple sclerosis.
AB - Several studies have reported a positive correlation between levels of soluble
adhesion molecules in serum or cerebrospinal fluid and cranial MRI activity. We
performed a cross-sectional study in 46 patients with newly diagnosed MS and
determined levels of soluble intercellular adhesion molecule-I (sICAM-I) as well
as vascular cell adhesion molecule-I (sVCAM-I) in correlation to the number and
area of gadolinium enhancing lesions on cranial magnetic resonance images (MRI).
The data revealed a significant positive correlation between sVCAM-I serum levels
and gadolinium enhancing lesions. In addition, CSF to serum ratios for sICAM-I
and sVCAM-I correlated to MRI activity. In patients with a single enhancing
lesion (SEL) there was a negative correlation between the QsCAM and the distance
of the SEL to the ventricles. As these adhesion molecules are stable and markers
of disease activity in MS, we further investigated sVCAM-I serum levels during
treatment with interferon beta-Ib (Betaferon). Significant increases in serum
levels for sVCAM-I in patients receiving Betaferon were associated with a
favourable treatment response after 1 year in 17 out of 19 patients and
correlated to decreased MRI activity, whereas stable or reduced sVCAM-I levels
occurred more often in non-responders (five out of six patients). Therefore it
can be hypothesized that soluble adhesion molecules are released from cerebral
endothelial cells as an early immunoregulatory activity of the immune system to
reduce cellular traffic across the blood brain barrier and this is further
enhanced by IFN-beta treatment.
PMID- 9762671
TI - Serum soluble intercellular adhesion molecule-I in MS: relation to clinical and
Gd-MRI activity and to rIFN beta-Ib treatment.
AB - The validity of serum sICAM-I levels to assess Multiple Sclerosis (MS) activity
was evaluated in 49 untreated definite relapsing-remitting (RR) patients. sICAM-I
levels were significantly (P = 0.0009) higher in the 'clinically active' group
(No 22) than in the 'clinically inactive' (No 27), whereas no different values
were found between patients with Gd-enhancing lesions at MRI (Gd-positive) (No
32) and patients without such lesions (Gd-negative) (No 17) independently of
their clinical activity. Among the 'clinically active' MS, the Gd-positive (No
16) subgroup showed significant (P < 0.05) lower sICAM-I levels when compared to
the Gd-negative (No 6) subgroup, but higher (P = 0.009) than those of the
'clinically inactive Gd-positive' (No 16) patients. The sICAM-I levels did not
differ between the two 'clinically inactive' subgroups Gd-positive (No 16) and Gd
negative (No 11). Finally the clinically active Gd-negative (No 6) showed sICAM-I
levels higher (P = 0.002) than the clinically inactive Gd-negative (No 11). The
specificity of high serum sICAM-I levels (above M +/- 2 s.d. of control values)
to assess the disease activity in MS resulted higher (100%) using clinical than
Gd-MRI activity (76%) as gold standard. The changes induced by 1 year recombinant
Interferon-beta-Ib (rIFN beta-Ib) treatment on sICAM-I serum levels were also
longitudinally investigated in 36 of the 49 RR MS. sICAM-I levels at baseline
significantly increased in the first 2 months (baseline vs 1st month P < 0.0001
and 1st vs 2nd month P = 0.02), persisted at high levels without any significant
change after 3 months, showed a temporary decrease at 6 months, then
significantly increased again at 9 and 12 months. Fourteen patients experienced
relapses, with a total of 20 relapses, during the whole treatment duration. The
mean relapse/rate and the frequency of patients with Gd-positive MRI scans
resulted significantly higher in the first semester compared to the second
semester of treatment. This study adds further insights into the validity of
serum sICAM-I to assess disease activity in MS and on the immunomodulatory
properties of rIFN beta-Ib.
PMID- 9762672
TI - Monitoring multiple sclerosis course and activity with TNF-alpha.
PMID- 9762673
TI - Relapse markers in multiple sclerosis: are in vitro cytokine production changes
reflected by circulatory T-cell phenotype alterations?
AB - In vitro tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma)
and interleukin-2 (IL-2) production, serum neopterin levels, and T-lymphocyte
subpopulations were determined on a monthly basis in 22 MS patients. We found
increased in vitro TNF-alpha production from 4 weeks on prior to the day of an
exacerbation. There was a significant correlation with in vitro IFN-gamma
release, the absolute blood monocyte count and the serum neopterin levels,
suggesting that monocytes stimulated by IFN-gamma play an important role in the
TNF-alpha production. Serial analysis of in vitro TNF-alpha production proved to
be a helpful tool in predicting relapses in MS patients. Furthermore, elevated
levels of IFN-gamma and IL-2 after stimulation with OKT3 during exacerbations
were demonstrated. These increases were not reflected by changes in T-lymphocyte
subpopulations. However, significant differences in T-cell subsets were observed
between controls and relapsing progressive patients.
PMID- 9762674
TI - In vitro cytokine profiles as indicators of relapse activity and clinical course
in multiple sclerosis.
AB - In vitro production of tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL
2), IL-4, IL-6, IL-10 and oligoclonal IgG (IgG OB) was evaluated in the aim to
investigate their profile in correlation with multiple sclerosis (MS) clinical
activity and clinical course. Whole blood stimulation with lipopolysaccharide or
concanavalin A was performed in 61 patients presenting with relapsing-remitting,
relapsing-progressive or chronic progressive MS; treatments received were: none,
azathioprine (AZA), cyclosporin, cyclophosphamide, subcutaneous interferon-beta
1a (IFN-beta 1a) and corticosteroids (CST). The cinetics of cytokine production
showed that (i) in the absence of treatment, TNF-alpha and IL-6 dropped
respectively after and during the periods surrounding relapse, while IL-4 was
increasing before and IL-10 after relapse; (ii) with AZA, TNF-alpha and IL-6
lowered before exacerbation, IL-4 prolonged high levels after and IL-10 before
relapse; (iii) with IFN-beta 1a, IL-10 was already increasing before relapse, and
TNF-alpha was higher after relapse. When cytokine levels were analysed
independently from MS clinical activity, the use of AZA inhibited IgG OB and TNF
alpha synthesis (P = 0.002) but increased IL-4 (P = 0.0024), whereas IFN-beta 1a
stimulated TNF-alpha and inhibited IgG OB and IL-4 production. CST inhibited TNF
alpha, IL-6, IL-4 and IgG OB synthesis. This study stresses both the weight of
clinical parameters and of methodology used in results obtained in cytokine
analysis in MS.
PMID- 9762675
TI - Myelin reactive T cells in the autoimmune pathogenesis of multiple sclerosis.
AB - Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous
system (CNS) leading to demyelination. Although it is widely accepted that
demyelination in MS results from an active inflammatory process, the cause of the
inflammation is still not completely resolved. Findings in experimental
autoimmune encephalomyelitis (EAE), an animal model of MS, and observations in
human MS have led to the hypothesis that MS is an autoimmune disease mediated by
autoreactive T cells with specificity for myelin antigens. The identity of the
brain antigen(s) which is (are) the primary target(s) of the autoimmune process
is not known, but current evidence indicates that myelin basic protein (MBP) is a
likely candidate. In this paper we will overview some of the experimental
evidence suggesting that MBP reactive T cells hold a central position in the
pathogenesis of MS, and discuss some of the currently tested therapeutic
strategies in MS which are directed towards the pathogenic MBP reactive T cells.
Although there appears to be no direct correlation between anti-MBP T cell
responses and clinical disease activity, some recent observations suggest that
monitoring of anti-MBP T cell responses could be helpful to study immunological
efficacy of experimental immunotherapies in MS.
PMID- 9762676
TI - The potential role of nitric oxide in multiple sclerosis.
AB - Nitric oxide (.NO) and its reactive derivative peroxynitrite (ONOO-) have been
implicated in the pathogenesis of multiple sclerosis (MS). They are cytotoxic to
oligodendrocytes and neurones in culture by inhibiting the mitochondrial
respiratory chain (complexes II/III and IV) and inhibiting certain key
intracellular enzymes. Recently .NO has been implicated as a possible
aetiological factor in reversible conduction block in demyelinated axons.
Inducible nitric oxide synthase (iNOS) is upregulated in the central nervous
system of animals with experimental allergic encephalomyelitis (EAE) and in
patients with MS. In some EAE models inhibiting iNOS activity decreases disease
severity whilst in other models disease activity is exacerbated. Raised levels of
nitrate and nitrite, stable end-products of .NO/ONOO-, are found in the
cerebrospinal fluid, serum and urine of patients with MS. CSF levels of nitrate
and nitrite correlate with blood-brain-barrier dysfunction, which suggests that
.NO may play a role in inflammatory blood-brain-barrier dysfunction. In a
longitudinal study on 24 patients with relapsing remitting and secondary
progressive MS, raised serum nitrate and nitrite levels correlated with a
relapsing course and infrequent relapses. However, no correlation was found
between raised serum levels of nitrate and nitrite and MRI activity, disease
progression, or the development of cerebral atrophy. In autoimmune mediated CNS
demyelinating disease .NO may be a double-edged sword, mediating tissue damage on
the one hand and on the other hand modulating complex immunological functions
which may be protective.
PMID- 9762677
TI - A unique population of circulating autoantibodies promotes central nervous system
remyelination.
AB - In previous studies we demonstrated that the humoral immune response directed
against unique central nervous system (CNS) antigens enhanced CNS remyelination
in the Theiler's virus experimental model of multiple sclerosis (MS). To expand
on this observation, a mouse IgM kappa monoclonal antibody (mAb) which enhances
CNS remyelination, was raised against normal mouse spinal cord homogenate.
Characterization of this mAb revealed that it is polyreactive towards variety of
intracellular antigens but also reacts to an unidentified surface antigen on
oligodendrocytes. The mAb is encoded by germline immunoglobulin genes without
somatic mutations consistent with the observation that it is a natural
autoantibody. Recently we generated another mouse IgM kappa mAb raised against
normal spinal cord homogenate, which also promotes CNS remyelination. Further
characterization revealed that both mAbs which promote remyelination have similar
binding characteristics. Conventionally Abs which recognize normal CNS
components, especially oligodendrocytes or myelin, have been considered to be a
disease marker or be involved in the pathogenesis of MS. However, we have
identified a unique population of circulating autoantibodies which are beneficial
for myelin repair. Therefore this observation indicates the need to reevaluate
autoantibody production against myelin components in CSF and blood as markers of
disease activity versus repair in MS.
PMID- 9762678
TI - A gene therapy approach to treat demyelinating diseases using non-replicative
herpetic vectors engineered to produce cytokines.
AB - A successful gene therapy approach in organ-specific autoimmune diseases, such as
multiple sclerosis (MS), encompasses the inhibition of the autoreactive T cells
or the modification of the target organ cells by the introduction of exogenous
'protective' genes. In MS, an autoimmune disease of the central nervous system
(CNS), the inciting autoantigen is still unknown and therefore the isolation of
autoreactive T cells may only be inferential. At present, gene therapy approaches
in MS should therefore aim to the modification of the target organ. Possible
candidate genes to be transferred within the CNS of MS patients are those coding
for anti-inflammatory cytokines (i.e. interleukin-4, interleukin-10, transforming
growth factor beta) which have been shown to ameliorate demyelinating diseases at
least in experimental models. However, a limiting factor for this therapy is the
difficulty to reach the CNS. A gene therapy approach using viral vectors able to
infect post-mitotic cells, such as those present within the CNS, without inducing
toxic reactions, may overcome this limitation. We propose to use non-replicative
herpetic vectors, which represent a viable gene-transfer alternative to the
classical retroviral and adenoviral vectors. Key advantages are their size, able
to accommodate multiple foreign genes, and their ability to infect post-mitotic
cells such as those present within the CNS. We first transferred a gene coding
for interleukin-4 within the CNS of mice undergoing experimental allergic
encephalomyelitis, an animal model for MS, using non-replicative Herpes Simplex
Virus type 1-derived vectors. We found that this approach ameliorates the disease
course and delays the disease onset. The establishment of this technique to
deliver anti-inflammatory cytokines within the CNS using herpetic vectors should
clarify the role of individual cytokines in the demyelinating process and allow
assessment of whether gene therapy using herpetic vectors is a feasible and safe
approach to treat human demyelinating disorders.
PMID- 9762679
TI - Are there indicators of remyelination in blood or CSF of multiple sclerosis
patients?
AB - Knowing the mechanisms and the times of remyelination is not only an intriguing
scientific challenge but it has also important consequences on the therapeutic
approach to multiple sclerosis (MS). The neural-cell adhesion molecule (N-CAM)
shows tempting suggestions about its possible involvement in reparative
mechanisms, and, finally, in remyelination. In fact, its levels progressively
increase in the cerebrospinal fluid (CSF) of acute MS patients, paralleling the
progressive clinical improvement after the attack. Some information is also given
about the ciliary neurotrophic factor (CNTF), whose CSF levels were found to be
increased in MS patients who were recovering from an acute exacerbation.
PMID- 9762680
TI - Disease activity and the immune set in multiple sclerosis: blood markers for
immunotherapy.
AB - There is no established immunological marker of multiple sclerosis activity,
which reflects the poor understanding of the immunopathogenesis of multiple
sclerosis. Passive measurement of the levels of soluble inflammatory markers,
whose half lives are usually measured in minutes and hours, can only indicate the
extent of instantaneous inflammation, which is known to fluctuate in multiple
sclerosis. We favour measurement of immune responses in vitro. As healthy
individuals have T cell reactivities to myelin proteins that are postulated to be
pathogenic in multiple sclerosis, we prefer non-antigen specific mitogen and
recall antigen assays as immunological markers. We illustrate their use in the
treatment of 27 patients with multiple sclerosis using a pulse of humanised anti
lymphocyte (CD52) antibody that caused prolonged T cell depletion. The mitogen
induced proliferation, and secretion of IFN-gamma, from peripheral blood
mononuclear cells in vitro was significantly reduced after treatment, suggesting
that immune responses had been modulated. Such observations will only gain
credence as an outcome measure if they are shown to correlate with clinical or
radiological measures of multiple sclerosis activity. Perhaps more importantly,
aspects of the pathogenesis of multiple sclerosis may be revealed by close
immunological surveillance of patients undergoing experimental treatments.
PMID- 9762681
TI - The expression of integrins on activated T-cells in multiple sclerosis. Effect of
intravenous methylprednisolone treatment.
AB - We studied the effect of intravenous methylprednisolone (MP) on the expression of
the integrins, LFA-1 and VLA-4, on activated blood T-lymphocytes in 17 patients
with relapses of clinically definite relapsing-remitting MS. MP treatment did not
induce changes in the expression of CD3, CD4, DR, LFA-1 or VLA-4 markers when
measured in the total population of lymphocytes in MS patients in relation to
treatment. Treatment influenced neither the LFA-1 nor VLA-4 positive cells within
the CD3+ population. MP treatment clearly decreased the DR+ CD3+ cells (P < 0.01)
and the percentage of DR+ CD3+ lymphocytes bearing VLA-4 (P < 0.01). However,
this was not the case when we studied the percentage of lymphocytes which
expressed LFA-1. Glucocorticoids did not influence the mean intensity of the
expression of the two integrins quantified in either total or DR+ CD3+
lymphocytes. Although, further research seems warranted to investigate a possible
effect of MP on lymphocyte integrin function, this work corroborates the idea
that MP treatment may interfere with the mechanisms of T-cell migration into CNS,
thus modulating the activity of multiple sclerosis.
PMID- 9762682
TI - Myelin basic protein-like material in the urine of multiple sclerosis patients:
relationships to clinical and neuroimaging changes.
AB - Urinary myelin basic protein-like material (MBPLM) represents material which is
cross-reactive with a cryptic epitope in peptide 84-89 of human myelin basic
protein. While normally present at moderate levels in the adult, these levels
rise higher in patients who have secondary progressive multiple sclerosis (MS).
The increase in urine MBPLM correlates with the burden of disease detected by T2
weighted cranial magnetic resonance imaging. There is no correlation between
urinary MBPLM and acute disease activity in relapsing-remitting MS. The first
major need for improving the clinical utility of measurements of MBPLM in urine
in MS patients is to delineate its exact chemical features so that assays may be
improved and a potential biological role of the MBPLM better understood. The
second major task is to apply the group data accumulated and apply them to
individual patients. This could prove to be means to individually direct
treatment and determine its effectiveness.
PMID- 9762683
TI - Urinary markers of disease activity in multiple sclerosis.
AB - Numerous markers of disease activity, representing different aspects of the
inflammatory cascade and pathogenic process in multiple sclerosis, can be
detected in the urine. Urinary monitoring provides distinct advantages over blood
and cerebrospinal fluid: it is easier to collect, allows frequent sampling and
acts as a natural integrator by capturing the excretion of a substance over a
prolonged period of time. We will discuss the principles, advantages, and
pitfalls of urinary monitoring in relationship to multiple sclerosis.
PMID- 9762684
TI - Free light chains in multiple sclerosis urine.
AB - We measured free kappa (kappa) and lambda (lambda) light chains in urine from
patients with definite multiple sclerosis (MS), other neurologic diseases (OND),
and normal controls by using an enzyme linked immunosorbent assay. Both kappa and
lambda light chains were higher in MS than OND or controls. In seven of eight
relapsing-remitting (R-R) MS patients serial studies showed that urinary kappa
chains were elevated during periods of worsening, and decreased during clinical
recovery. In contrast, the levels of kappa chains did not correlate with clinical
activity in 10 progressive (P) MS patients. Further correlation of urinary light
chains with neurologic evaluations in R-R and P MS patients over a longer period
are needed to determine their clinical and biological relevance.
PMID- 9762685
TI - Identification of brain atrophy with MRI in MS.
PMID- 9762686
TI - Neurophysiological and cognitive markers of disease evolution in multiple
sclerosis.
AB - Both evoked potentials and cognitive tests may provide useful information which
cannot be derived from the clinical observation. For this reason, there have been
some attempts to use EPs in monitoring the natural history of the disease and in
assessing the efficacy of therapeutic trials. However, no conclusion can be
derived from the few available data. Although MRI is more sensitive than EPs in
revealing new lesions in brain, cerebellum and brainstem, EPs are more sensitive
in revealing optic nerve and spinal cord lesions. Moreover, the poor relationship
between brain MRI abnormalities and disability has raised the possibility that
cognitive evaluation may be an additional sensitive marker of brain involvement
over time. Since the gold standard for the assessment of disease activity is
uncertain, it is therefore advisable that frequent MRI, EPs and cognitive
assessment may integrate clinical outcomes measured by conventional scales, both
in the study of the natural disease course and in monitoring clinical trials.
PMID- 9762687
TI - Body fluid markers to monitor multiple sclerosis: the assays and the challenges.
AB - The need for reliable markers of disease activity in multiple sclerosis (MS) to
better guide basic research, diagnosis, treatment, and monitoring of therapy is
well-recognized. A recent European Charcot Foundation Symposium (Body fluid
markers for course and activity of disease in multiple sclerosis (Madrid, Spain,
October 2-4, 1997) organized by the European Charcot Foundation and the Fundacion
Espanola de Esclerosis Multiple (the Spanish Multiple Sclerosis Foundation)
brought together experts in the field to review the state of the art for the
technology measuring markers in body fluids. An array of different approaches was
presented to measure a wide diversity of classic and novel marker molecules,
including cytokines, adhesion molecules, myelin compounds, and free antibody
light chains, in either blood, urine, or cerebrospinal fluid. Here, recent
progress in these approaches is assessed in the context of distinct
pathophysiological stages of the disease, the requirements which such molecules
and assays should ideally meet, and the practical and conceptual challenges which
they face. Recommendations for further improvements are described.
PMID- 9762688
TI - Intracellular bacteria in protozoa.
AB - Intracellular bacteria in humans are typically detrimental, and such infections
are regarded by the patients as accidental and abnormal. In protozoa it seems
obvious that many bacteria have coevolved with their hosts and are well adapted
to the intracellular way of life. Manifold interactions between hosts and
intracellular bacteria are found, and examples of antibacterial resistance of
unknown mechanisms are observed. The wide diversity of intracellular bacteria in
protozoa has become particularly obvious since they have begun to be classified
by molecular techniques. Some of the bacteria are closely related to pathogens;
others are responsible for the production of toxins.
PMID- 9762689
TI - Neuronal control of mammalian vocalization, with special reference to the
squirrel monkey.
AB - Squirrel monkey vocalization can be considered as a suitable model for the study
in humans of the neurobiological basis of nonverbal emotional vocal utterances,
such as laughing, crying, and groaning. Evaluation of electrical and chemical
brain stimulation data, lesioning studies, single-neurone recordings, and
neuroanatomical tracing work leads to the following conclusions: The
periaqueductal gray and laterally bordering tegmentum of the midbrain represent a
crucial area for the production of vocalization. This area collects the various
vocalization-triggering stimuli, such as auditory, visual, and somatosensory
input from diverse sensory-processing structures, motivation-controlling input
from some limbic structures, and volitional impulses from the anterior cingulate
cortex. Destruction of this area causes mutism. It is still under dispute whether
the periaqueductal region harbors the vocal pattern generator or merely couples
vocalization-triggering information to motor-coordinating structures further
downward in the brainstem. The periaqueductal region is connected with the
phonatory motoneuron pools indirectly via one or several interneurons. The
nucleus retroambiguus represents a crucial relay station for the laryngeal and
expiratory component of vocalization. The articulatory component reaches the
orofacial motoneuron pools via the parvocellular reticular formation. Essential
proprioceptive feedback from the larynx and lungs enter the vocal-controlling
network via the solitary tract nucleus.
PMID- 9762690
TI - Analysis of laughter and speech sounds in Italian and German students.
PMID- 9762691
TI - Orientation-reversal and phase-reversal visual evoked potentials in full-term
infants with brain lesions: a longitudinal study.
AB - The onset and maturation of visual cortical mechanisms can be recorded by using
steady-state visual evoked potentials. The aim of this study was to evaluate and
compare orientation-reversal (OR) and phase-reversal (PH) VEP as indicators of
the maturation of cortical function in a population of fullterm infants with
brain lesions on neonatal MRI. Forty-six infants with brain lesions on neonatal
MRI were tested on both PH and OR VEP at 8 reversals/second at the age of 5
months and, if the responses were not significant, at a lower temporal frequency
(4 reversals/second). Children whose VEPs were not significant at 5 months were
tested longitudinally at 6, 9, 12 and 18 months. The results showed that 23 of
the 46 infants (50%) did not show significant responses at 5 months and that
while in 7 of the 23 (14% of the whole cohort) the responses became significant
between 5 and 12 months, in the other 16 infants (34%) the VEP responses were
persistently abnormal. Children with focal lesions, such as focal infarction or
haemorrhages, tended to show normal or only mildly delayed VEP while more
generalised lesions, such as the ones seen in infants with hypoxic-ischaemic
encephalopathy grade 2 and 3, tended to be associated with abnormal VEP
responses. The involvement of the optic radiations and occipital cortex was not
always associated with abnormal VEP responses but the concomitant involvement of
the basal ganglia was always associated with abnormal VEP. We were also able to
demonstrate that VEP can be also used as a prognostic indicator: while normal OR
VEP are reliably associated with a normal visual and neurodevelopmental outcome,
abnormal 4 OR or 8 PH at 5 months are consistently associated with abnormal
outcome.
PMID- 9762692
TI - Characterization of the mitochondrial genome in childhood multiple sclerosis. I.
Optic neuritis and LHON mutations.
AB - The occurrence of optic neuropathy in patients with MS-like disorders who carry
one of the pathogenetically significant LHON mutations as well as the higher
incidence of maternal transmission in familial cases of MS support the hypothesis
that mitochondrial genes may be implicated in susceptibility to MS. We sequenced
the entire mtDNA of six children with MS who developed optic neuritis as early
and prominent visual involvement. The analysis revealed a high degree of
nucleotide variations relative to the standard mtDNA sequence. After excluding
various synonymous nucleotide changes and common neutral polymorphisms, eight
discrete novel missense mutations within the protein coding, tRNA or rRNA genes
were detected. None of the eight polymorphic sites were found in common between
the patients with MS. Of particular interest was the observation that five of six
children carried a total of nine secondary LHON mutations at nucleotide positions
4216, 4917 or 13708. We conclude that variation in mtDNA is unlikely to
contribute to genetic predisposition for MS. However, secondary LHON mutations
may be regarded as additional risk factor for developing prominent optic nerve
involvement. The association of individual sets of mtDNA variations with
phenotypic presentation in certain subgroups of MS patients remains to be
clarified.
PMID- 9762693
TI - Correlation between neonatal cranial ultrasound, MRI in infancy and
neurodevelopmental outcome in infants with a large intraventricular haemorrhage
with or without unilateral parenchymal involvement.
AB - During a 7-year-period, 1625 infants of 34 weeks gestation or less were enrolled
in a prospective ultrasound (US) study. One hundred and eleven (6.8%) infants
developed a large intraventricular haemorrhage (IVH) with or without unilateral
parenchymal involvement (PI). Fifty-six of these 111 infants survived (50.4%) and
in 23 (41%) of them a magnetic resonance imaging (MRI) study was performed beyond
12 months corrected age. There appeared to be a good agreement between neonatal
ultrasound findings and MRI changes noted in infancy. Of the 10 cases with a
large IVH without PI (group A), seven had a VP shunt with complete decompression
of previously enlarged ventricles. Six of these seven infants had periventricular
hyperintensity (PVHI) but none developed cerebral palsy (CP). Two of the ten
cases without a VP shunt had irregular ventricular enlargement (VE) with PVHI in
one. Both developed CP. Seven cases showed thinning of the corpus callosum. Of
the 13 cases with a large IVH associated with PI (group B), the site of the PI
could still be recognised on MRI and the degree of communication of the
porencephalic cyst (PC) with the lateral ventricles correlated well with neonatal
US findings. On MRI, VE was present in only 6 cases. Wallerian degeneration was
present in 9/13 infants and all but one developed a hemiplegia. In 12/13 cases
there was thinning of the corpus callosum, either focal or diffuse. PVHI was
present in all infants. In 6/13 PVHI was only present around the PC.
Neurodevelopmental outcome differed for both groups. CP was only present in 2/10
infants in group A, compared to 11/ 13 in group B. Global delay, in the absence
of CP, was more common in infants with a large IVH than in those with associated
PI. CONCLUSION: Combining neonatal US with MRI in infancy enhances our
understanding of the long-term effects of severe haemorrhagic brain lesions,
occurring in preterm infants.
PMID- 9762694
TI - Clinical observations in autosomal recessive spastic paraplegia in childhood and
further evidence for genetic heterogeneity.
AB - Among our 23 families (32 cases) with autosomal recessive hereditary spastic
paraplegia (AR-HSP) all presenting in childhood, 9 families had the "pure" form.
Occasional patients with this form had upper extremity hyperreflexia, pes cavus
and sphincter disturbances, even at the early stages. Fourteen families were
classified as the "complicated" types which manifested with mental retardation
and cerebellar abnormalities. The evolution and severity was variable, but was
generally consistent within families. Carriers (parents) did not manifest any
signs. A total of 5 multiplex families with "complicated" type were used to test
for a genetic heterogeneity to the region on chromosome 8p12-q13 where the "pure"
AR-HSP has been mapped previously. No evidence in favor of linkage was detected
in 3 of our families, thus we further supported genetic heterogeneity for AR-HSP.
PMID- 9762695
TI - Altered antioxidant enzyme activities in children with a serious adverse
experience related to valproic acid therapy.
AB - Specific oxidative metabolites of valproic acid (VPA) have been associated with
the clinically defined toxicity of the drug. To investigate the role of enzymatic
detoxification in clinical toxicity, we compared activities of five antioxidant
enzymes in 15 patients with a serious adverse experience (SAE) related to VPA
therapy, to enzyme activities measured in 35 patients with good clinical
tolerance of VPA, and 50 healthy, age-matched subjects. These enzymes included
glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), glutathione
transferase, superoxide dismutase, and catalase in erythrocytes; and GSH-Px in
plasma. We also determined levels of Se, Cu, and Zn, trace elemental cofactors
for these enzymes, in plasma from each individual. In patients with a VPA
associated SAE, GSH-Px was significantly depressed and GSSG-R was significantly
elevated relative to values for the other groups. Selenium and zinc
concentrations were lower in SAE patients than in controls. These findings may
indicate a role for selenium dependent antioxidant activity in individual
susceptibility to an SAE related to VPA therapy.
PMID- 9762696
TI - Early and late onset manifestations of cerebral vasculitis related to varicella
zoster.
AB - Varicella-zoster associated cerebral vasculitis (VZCV) as a cause of cerebral
infarction has hitherto been considered a rare condition. Ischemic stroke in
previously healthy children has occurred during recovery from chickenpox or has
been attributed to virus reactivation among immunosuppressed patients. The
clinical, radiologic and immunologic findings in four children with VZCV will be
reported. Clinical manifestations included sudden onset of hemiparesis, motor
aphasia and disturbed consciousness in previously healthy children. Only one
child had a history of chickenpox six weeks prior to the onset of stroke, whereas
a latency period of up to four years between chickenpox and the onset of stroke
was found in the other three children. Diagnosis of VZCV was confirmed repeatedly
by demonstrating intrathecal production of varicella-zoster IgG antibodies in
three children or a four-fold increase of varicella-zoster serum IgA-antibodies
in one child. Intrathecal production of antibodies against other latent viruses
and borreliosis could be excluded. PCR for varicella on CSF, performed in two
patients, remained negative. No intrathecal production of varicella-zoster
antibodies has been found in a control group of twenty clinically healthy
children (age range from 2-18 years) with a previous varicella infection. During
follow-up two children recovered completely whereas two children still suffer
from serious neurological deficits. Immunological investigations, performed in
three children, showed circulating immune-complexes with slightly lowered
complement concentrations in two patients. In addition a lowered T-helper/T
suppressor cell ratio of unknown origin was found in three children. These
immunological findings will be discussed in the light of the pathophysiology of
VZCV.
PMID- 9762697
TI - Quantification of cyclical fluctuations in cerebral blood volume in healthy
infants.
AB - Cyclical fluctuations in cerebral blood flow velocity in Doppler measurements are
a well known phenomenon. In 1992 Livera et al have shown in one patient, that
cyclical fluctuations of cerebral blood volume could be measured with near
infrared spectroscopy (NIRS). The aim of the present study was a quantification
of the amplitude of cyclical fluctuations of cerebral blood volume (represented
by total haemoglobin [Hbtot]) in a large number of healthy infants. Furthermore
changes of oxygenated haemoglobin (HbO2) and deoxygenated haemoglobin (Hb) were
investigated. Measurements were done during two hours of undisturbed daytime
sleep. Fifty-eight infants (30 male, 28 female) were included in the study. All
but one infant showed cyclical fluctuations. For quantification of cyclical
fluctuations only periods during quiet sleep with excellent tracing quality were
used. A number of 7894 cycles was analyzed for each of the three NIRS parameters.
The median amplitude of the cycling fluctuations was: delta Hbtot 1.1 mumol/l,
delta HbO2 1.1 mumol/l, and delta Hb 0.2 mumol/l. The frequency was changing
within a range of 3 to 6 cycles/minute. Polynominal regression analysis showed
that the relationship of delta HbO2 and delta Hbtot was distinctively stronger
compared to the relationship of delta Hb and delta Hbtot. In conclusion we think
that these data represent "normal ranges" for parameter fluctuations in long-time
NIRS tracings.
PMID- 9762698
TI - A craniospinal enterogenous cyst: case report.
AB - An enterogenous cyst of the craniospinal region producing medullary compression
is reported in a 4.5-year-old boy. The patient presented with stiffness of the
neck and headache, but otherwise without neurological deficits. Magnetic
resonance imaging (MRI) demonstrated a high-intensity mass extending from the
cerebellomedullary cisterna to the second cervical vertebra flattening the
medulla and the upper cervical cord. Complete recovery ensued following total
excision of the cyst. Histologically, the cyst was lined by a single layer of PAS
positive columnar epithelium. Presentation of this unusual case is discussed
together with a review of the literature.
PMID- 9762699
TI - Aplasia of the depressor anguli oris muscle: a rare cause of congenital lower lip
palsy?
AB - Congenital unilateral lower lip palsy (CULLP) with or without additional
malformations is a well-known limited variation of congenital unilateral facial
palsy. Some electromyographical studies referred to a hypoplasia or an aplasia of
the depressor anguli oris muscle. However, no attempt has been made to
investigate the cause for this mimical disorder by using imaging procedures. We
examined the occurrence of the depressor anguli oris muscle in 7 patients
presenting with congenital lower lip palsy by using B-scan sonography. In 6 of
the patients, the muscle was well-developed on the affected side, but only in one
patient the muscle seemed to be completely absent. Thus, in the majority of
cases, hypoplasia or aplasia of the depressor anguli oris muscle is obviously not
the reason for this mimical disorder. This observation may be important with
regard to a possible therapeutic management.
PMID- 9762700
TI - Familial congenital horizontal gaze paralysis and kyphoscoliosis.
AB - Congenital horizontal gaze paralysis is a rare disorder which may be associated
with severe scoliosis of early onset. We present the clinical findings of two
sisters with this syndrome. The additional finding of a unique pericentric
inversion of chromosome 12 is considered to be incidental. Every child with
congenital horizontal gaze paralysis should be evaluated for a possibly
associated scoliosis. If present, a diagnosis of this presumably autosomal
recessive syndrome can be made with appropriate treatment and genetic counseling.
PMID- 9762702
TI - Age-related changes in the cytoarchitectonics of the human sensorimotor cortex.
AB - The projection zones of the movement analyzer show a level of maturity which is
required for maintaining the self-regulatory processes in children from the first
days of life [4, 8]. The cytoarchitectonics of the motor zone of the cerebral
cortex have been studied in a small number of people and at limited ages [1, 2,
4, 10]. One of the leading age-related changes consists of changes in neuronal
and interneuronal connections, which have significant influences on the systems
organization of the brain and its function as an integral organ. Pyramidal
neurons are regarded as the main universal type of cortical neuron, in which the
structure of the receptive surface supports transmission of a wide range of
polymodal signals [1]. Large pyramidal neurons in layers III and IV can establish
connections with all the neurons in a column of cells, which apparently leads to
complete and reliable functional interactions between neurons [1, 6]. The aim of
the present work was to study the quantitative changes in pyramidal neurons in
layers III and IV in various fields of the human sensorimotor cortex from birth
to the age of 20 years.
PMID- 9762701
TI - Changes in neurotransmitters in multiple sclerosis.
AB - Patients with multiple sclerosis were found to have increased cerebrospinal
fluid, noradrenaline, and excitatory amino acid (glutamate and aspartate) levels,
with increased blood glutamine, asparagine, and glycine levels. An association
was found between these biochemical parameters and the nature and severity of
neurological symptoms, as well as with the course of the disease.
Neurotransmitters are proposed to have a role in the pathogenesis of multiple
sclerosis, particularly in the biochemical mechanisms of the relationship between
the nervous and immune systems, as well as in the neurochemical mechanisms
underlying the development of neurological deficit.
PMID- 9762703
TI - Differentiation of neurons in the locus ceruleus after allotransplantation into
previously denervated white rat hippocampus.
PMID- 9762704
TI - Age-related changes in oxytocinergic neurosecretory cells in the accessory
magnocellular neuroendocrine nuclei of the hypothalamus in rats.
PMID- 9762706
TI - Adaptive regulation of the nonlinear dynamics of electrical activity of the
brain.
AB - A programmable system was used to provide contingent reinforcement of EEG cycles
corresponding to a selected criterion in a dynamic regime. Use of automated
reinforcing stimulation of emotionally positive zones of the hypothalamus led to
a significant increase in the number of cycles with the characteristics specified
by the dynamic regime within the dominant EEG frequency bands. This effect lasted
for some time after withdrawal of reinforcing stimulation, and then died down
gradually. These changes in the EEG activity structure did not occur in
conditions of nonassociated hypothalamic stimulation. Pseudoreinforced background
EEG cycles showed complex nonlinear dynamics with competitive interactions
between processes in which the large dimensionality of the attractor was
difficult to interpret because of indeterminacy in the trends of the dominant
process. In contingent hypothalamic stimulation, the form of the correlation
integral changed towards a predominance of a single nonlinear process determining
all the activity recorded. In fact, a single dominant nonlinear process was
formed, which became responsible for the entire dynamics of the system with
concordance of its internal structure.
PMID- 9762705
TI - Ribonuclease improves the state of hippocampal sections in the post-ischemic
period.
AB - Living hippocampal slices from Wistar rats were used to study the dynamics of
changes in population electrical responses in field CA1 to electrical stimulation
of Shaffer collaterals during the development of ischemia (imposed by exclusion
of oxygen and glucose from the perfusion solution). These studies showed that
during ischemia, addition of ribonuclease (a blocker of protein synthesis) to the
perfusion solution resulted in a significantly smaller increase in the latent
period of the response and slowed the onset of the reduction in the amplitude of
the evoked potential, and promoted faster recovery of the response after the
ischemia session ended. It is suggested that the reduction in protein synthesis
due to ribonuclease preserved energy reserves in the nerve tissue, which in turn
promoted more complete recovery of neuron function in the post-ischemic period.
PMID- 9762707
TI - Role of enkephalinergic brain structures in regulating motivated behavior in rats
with lesioned serotoninergic neurons.
AB - The behavioral effects of injections of enkephalin into the substantia nigra or
dorsal raphe nucleus were studied in rats with lesioned serotoninergic
structures. Lesions were produced by intracerebral administration of the
neurotoxin 5,7-dihydroxytryptamine. Treated rats showed normalization of
conditioned drinking reflex extinction. It is proposed that there is a tight
connection between the normalizing effects of enkephalin on rat behavior in
conditions of deficient brain serotoninergic system function and increases in the
efficiency of presynaptic inhibition of dopaminergic neurons.
PMID- 9762708
TI - Conditioned reflex release of dopamine in the nucleus accumbens after disruption
of the hippocampal formation in rats.
AB - Vital intracerebral microdialysis combined with HPLC with electrochemical
detection was used to study changes in dopamine release in the nucleus accumbens
during the development and realization of an emotional conditioned response in
hooded rats with lesions to the hippocampal formation. These studies showed that
one month after bilateral administration of ibotenic acid into the hippocampal
formation, rats had weakened emotional responses to contextual stimuli. The
process of development of the conditioned reflex was accompanied by higher-level
and longer-lasting release of dopamine in the nucleus accumbens than in sham
operated rats. Dopamine release levels in the nucleus accumbens during
realization of the conditioned reflex to contextual stimuli in rats with
hippocampal lesions and sham-operated rats were identical.
PMID- 9762709
TI - Role of the cholinergic systems of the dorsal and ventral striatum of the rat
brain in controlling learned movements.
AB - Comparative studies were performed of the effects of injections of a cholinergic
agonist (carbachol) and antagonist (scopolamine) into the ventral and dorsal
striatum on the performance of a learned movement involving prolonged maintenance
of extension of the forelimb in rats. Doses of carbachol (0.03-3.00 micrograms)
into the ventral striatum were accompanied by increases in the numbers of
movements with prolonged maintenance of extension with application of pressure
against an obstacle, with a simultaneous decrease in the percentage of rapid
nonreinforced movements (by an average of 18.8%). Injections into the dorsal
striatum disrupted slow movements which were not reinforced during training, on a
background of stable performance of the learned reflex. Doses of scopolamine (0.3
3.0 micrograms) into both the dorsal and ventral parts of the striatum produced
increases (by 22.7 +/- 8.2% and 68.9 +/- 14.3%) in the numbers of rapid
nonreinforced movements typical of the repertoire of untrained animals. These
data led to the suggestion that the cholinergic system of the ventral striatum is
involved in the maintenance of forelimb muscle tone in rats during the
performance of movements in which pressure is applied to an obstacle. The
cholinergic system of the dorsal striatum does not have this property, but plays
a significant role in the process of learning new sensory-controlled movements.
PMID- 9762710
TI - Adenylate cyclase system of the rat striatum: regulatory properties and the
effects of gangliosides.
AB - The activity and regulatory properties of the adenylate cyclase system of the rat
striatum were studied. Agents such as Gpp(NH)p, forskolin, and NaF were found to
show classical in vitro stimulation of adenylate cyclase activity in the striatum
membrane fraction. Dosage of rats with a preparation containing gangliosides (30
mg/kg, 6 i.p. injections) led to prolonged reductions in basal striatal adenylate
cyclase activity. Two weeks after ganglioside administration, enzyme activity was
reduced by 48% and remained lower than in controls (by 18%) even a month after
injections. In vitro studies of the effects of gangliosides on adenylate cyclase
activity in whole brain and striatal synaptosomes from rats showed that
gangliosides have modulating actions on the adenylate cyclase system of the
striatum, mainly due to changes in the catalytic function of the enzyme itself,
and have no significant effect on the GTP-binding center of G-protein.
PMID- 9762711
TI - Morphofunctional studies of the interactions of the glutamatergic, cholinergic,
and dopaminergic systems in the neostriatum.
AB - Morphological, electrophysiological, and behavioral experiments were used to
study the interactions of the glutamatergic, cholinergic, and dopaminergic
systems in the neostriatum of white rats with unilateral lesions of the
mesostriatal dopaminergic system induced by 6-hydroxydopamine. The neostriatum
was shown to contain both synaptic and interneuronal nonsynaptic interactions
between these neurochemical systems. It is suggested that glutamate, which is
present in excess in conditions of prolonged dopamine deficiency, has toxic
effects on corticoneostriatal synaptic connections.
PMID- 9762712
TI - Possible mechanisms of delay in initiation of voluntary movements.
AB - Studies were made of psychomotor responses and accompanying cortical evoked
potentials in healthy subjects and patients with Parkinson's disease.
Measurements showed that delays in a variety of psychomotor responses resulted
from delays in movement initiation. The frontal regions showed increases in the
N2 component of evoked potentials and delayed development of P3 waves. It is
suggested that delayed initiation of movements in patients with Parkinson's
disease might be associated with strengthening of frontal inhibitory systems,
preventing the onset of movements.
PMID- 9762713
TI - Effects of electrical stimulation of the caudate nucleus on functionally
identified neurons of the sensorimotor cortex in the cat brain.
AB - Paired stimulation was used to study the effects of the caudate nucleus on the
specific and nonspecific responses of projection neurons of the sensorimotor
cortex in the cat brain. Caudal influences on the neurons being studied had
insignificant effects on specific peripheral evoked responses. Nonspecific
peripherally evoked activity was in most cases inhibited by caudate spike
activity, and the pattern of evoked activity underwent significant modulation in
conditions of a constant type of peripherally evoked response. It is suggested
that the caudate nucleus acts as a filter of proprioceptive information in the
cortex or in pathways to the cortex: specific corticopetal information is passed
unchanged, while nonspecific signals are predominantly inhibited or significantly
modulated.
PMID- 9762714
TI - Activation of the cholinergic system of the striatum improves the differentiation
of sound signals by dogs.
PMID- 9762715
TI - Effects of lesions to the parafascicular nuclei of the thalamus on the
development of a conditioned active escape reflex in rats.
PMID- 9762716
TI - Effects of lesioning of the parafascicular nucleus of the thalamus on an operant
food-procuring reflex in rats.
PMID- 9762717
TI - Spatial organization of afferent inputs to the limbic cortex in rats and cats.
PMID- 9762718
TI - Residual lesions of operant behavior in monkeys following recovery from MPTP
induced Parkinson-like syndrome.
PMID- 9762719
TI - Role of atrial natriuretic peptide in the development of arterial hypertension in
patients with pubertal hypothalamic syndrome.
AB - The role of a depressor factor, atrial natriuretic peptide, in the development of
arterial hypertension in adolescents with pubertal hypothalamic syndrome was
studied in 52 patients and 13 healthy males aged 13-24 years. The duration of
disease was 2-11 years. Radioimmunological methods were used to measure plasma
atrial natriuretic peptide, plasma renin activity, and serum aldosterone.
Patients with borderline arterial hypertension were found to have a significant
reduction in their atrial natriuretic peptide levels, and this correlated
directly with the renin-aldosterone system, demonstrating insufficiency of the
depressor system in patients with pubertal hypothalamic syndrome and the
involvement of atrial natriuretic peptide in the development of arterial
hypertension, along with disturbances in the functional relationship between
atrial natriuretic peptide and the renin-aldosterone system.
PMID- 9762720
TI - Desensitization of the post-synaptic membrane of neuromuscular synapses induced
by spontaneous quantum secretion of mediator.
AB - Experiments on isolated frog neuromuscular junctions in voltage-clamped
conditions demonstrated increases in the probability of spontaneous release of
quanta of mediator, resulting in increases in the K+ ion concentration in the
perfusion solution, and changes in the endplate miniature current amplitude
induced by increased quantum generation were studied. Factors promoting the
desensitization of the post-synaptic cholinergic membrane (inhibition of
acetylcholinesterase and addition of proadifen) to levels greater than a certain
(critical) frequency of endplate miniature current of the order of 50 spikes/sec
were found to result in accumulation of activity and progressive reductions in
the sensitivity of the post-synaptic membrane to the mediator acetylcholine.
PMID- 9762721
TI - Effects of delta-sleep-inducing peptide in cerebral ischemia in rats.
AB - Experimental studies were carried out to investigate the neuroprotective effects
of delta sleep-inducing peptide in animals with cerebral ischemia induced by
bilateral compression of both carotid arteries, and to compare the efficacy of
this peptide with that of MK-801. These studies led to the conclusion that the
peptide had pronounced anti-ischemic effects, which were evident within 24 h and
consisted of reductions in the severity of postural abnormalities in rats with
bilateral cerebral ischemia, along with a reduction in lethality. Comparison of
the efficacies of peptide and MK-801 showed the peptide to have the greater
neuroprotective effect. These results are regarded as providing an experimental
basis for using the peptide as a therapeutic agent in patients with stroke.
PMID- 9762722
TI - Question of time in studies of the neuronal correlates of behavior.
PMID- 9762723
TI - Role of the functional state of the central nervous system in the mechanism
forming responses from the peripheral and central parts of the visual analyzer.
AB - Chronic experiments on rabbits showed that changes in the functional state of the
central nervous system induced by Nembutal and changes in the brainstem reticular
formation induced by aminazine had significant effects on the formation of the
early receptor potential, a-wave, and oscillatory potentials of retinal ERG
signals, as well as on oscillatory potentials in the superior colliculi and
visual cortex. Nembutal inhibited the formation of the early receptor potential,
the a-wave, and the second and third ERG oscillatory potentials, and had similar
effects on the oscillatory potentials of the superior colliculi and the visual
cortex. Only the first oscillatory potential was enhanced in all visual system
structures. Aminazine had long-lasting enhancing effects on the formation of the
early receptor potential and the a-wave and on the oscillatory potentials of the
retina, superior colliculi, and visual cortex. This enhancement may be associated
with "release" of the retina and central structures from the constant inhibitory
influences of the brainstem reticular formation.
PMID- 9762724
TI - Blood flow dynamics in different layers of the somatosensory region of the
cerebral cortex on the rat during mechanical stimulation of the vibrissae.
AB - The present work reports studies of the quantitative spatial and temporal
characteristics of changes in local blood flow in different layers of the
somatosensory cortex of rats during adequate mechanical stimulation of the
vibrissae. Studies were performed using 34 Wistar rats. Skull trepanning was
performed under urethane (1 g/kg) anesthesia. Television-guided microscopy was
used to introduce a set of three platinum electrodes (100 microns in diameter,
with tip diameters of 30-40 microns) into the somatosensory cortex projection
zone of the vibrissae. The first and third electrodes were positioned in cortical
layers I-III and IV-VI and the central electrode was used to generate hydrogen
within the tissue. Electrode positions were confirmed histologically after
experiments. Animals were placed on artificial ventilation and one or all
vibrissae were stimulated at a frequency of 3 Hz for 60 sec, with interstimulus
intervals of 3 min. Changes in the local blood flow were measured during
stimulation and for 1 min afterwards, using the hydrogen clearance method, and
brain tissue impedance was also measured. There was a small (up to 5-7%)
reduction in blood flow in the first seconds of stimulation, which was followed
15-25 sec later by an increase and subsequent return to initial when stimulation
stopped. The increases in blood flow during stimulation of all vibrissae were by
24.2 +/- 6.7% (n = 36) in layers IV-VI and 24.5 +/- 5.6% (n = 34) in layers I
III; increases in response to stimulation of single vibrissae were by 19.4 +/-
7.4% (n = 28) and 17.8 +/- 6.4% (n = 28) respectively. The dynamics of impedance
changes corresponded to those of blood flow changes. Thus, heterogeneity was
found in changes of local brain blood flow in different layers of the
somatosensory cortex during increases in cortical functional activity.
PMID- 9762725
TI - Effects of transcranial micropolarization of the frontal cortex on the state of
motor and cognitive functions in extrapyramidal pathology.
PMID- 9762726
TI - Mechanisms of drug transfer across the human placenta.
AB - In this review we summarized literature data on the mechanisms of human placental
drug transport studied in the isolated perfused placental cotyledon, placental
membrane vesicles or trophoblastic cell cultures. Overall human placental drug
transport rarely exceeds the transfer of flow-dependent and membrane-limited
marker compounds. Interestingly, relatively often placental drug transfer
appeared to be much smaller, indicating impaired trans-placental transport,
depending on the physico-chemical characteristics of the drug or placental
factors such as tissue binding or metabolism. Although in perfusion studies
overall human placental drug transport occurs by simple diffusion, at the
membrane level several drug transport systems have been found, mainly for drugs
structurally related to endogenous compounds.
PMID- 9762727
TI - Clinical pharmacokinetics of antimicrobial drugs in cystic fibrosis.
AB - The disposition of many drugs in cystic fibrosis is abnormal compared with
healthy individuals. In general, changes include an increased volume of
distribution expressed in liters per kg bodyweight for highly hydrophilic drugs
such as aminoglycosides, and, to a lesser extent, for penicillins and
cephalosporins, together with an increased total body clearance. The main reason
for the increased volume of distribution is the increased amount of lean tissue
per kg bodyweight, since patients with CF are generally undernourished and have a
paucity of adipose tissue. The reason for the increased renal clearance is less
clear. Increased glomerular filtration and tubular secretion have been observed.
Protein binding generally is unaltered in CF. The fluorquinolones and vancomycin
show no altered pharmacokinetics in CF although gastro-intestinal absorption may
be delayed for fluorquinolones. Sulphamethoxazole shows increased clearance due
to an increased acetylation and, in the case of trimethoprim, renal clearance is
increased compared with healthy individuals. As a consequence, drugs that show
increased clearance, will lead to reduced serum concentrations and smaller AUCs
and therefore CF patients require larger doses per kg bodyweight.
PMID- 9762728
TI - Clinical pharmacokinetics of camptothecin topoisomerase I inhibitors.
AB - In this review the clinical pharmacokinetics of camptothecin topoisomerase I
inhibitors, an important new class of anticancer drugs, is discussed. Two
prototypes, topotecan and irinotecan, are currently marketed in many European
countries and the USA for the treatment of patients with ovarian and colorectal
cancer, respectively. Other camptothecin derivatives, including lurtotecan, 9
aminocamptothecin (9-AC) and 9-nitrocamptothecin (9-NC), are at different stages
of clinical development. The common property of camptothecin analogues is their
action against DNA topoisomerase I, but beyond this similarity the compounds
differ widely in terms of antitumour efficacy, pharmacology, pharmacokinetics and
metabolism. We review chemistry, mechanism of action, stability and bioanalysis
of the camptothecins. Dosage and administration, status of clinical application,
pharmacokinetics, pharmacodynamics and drug interactions are discussed.
PMID- 9762729
TI - Medication control in hospitals: a practical approach to the problem of drug-drug
interactions.
AB - An important task of pharmacists is medication control by screening the
medication of an individual patient. Many computerized drug interaction screening
programs are available, but they all have their drawbacks. Screening without a
computerized program is possible, but very time-consuming. In contrast to daily
living at home, the patient in a hospital setting is carefully monitored and
relevant biochemical parameters are regularly checked. Many potential drug
interactions are countered immediately by changing (dosage of) medication. The
aim of our study was to determine the number of drug-drug interactions and
(pseudo)double medications on the internal, pulmonary and cardiological ward in
order to discuss them with the physicians. During this discussion the clinical
relevance of interactions was determined. We conclude that the number of
clinically relevant interactions and (pseudo)double medication is limited, but
that the role of the pharmacist is an important one, especially with regard to
medication, that is not regularly used on a ward. Potential drug interactions
should be predicted and dealt with by close teamwork of physician and pharmacist
at the moment medication is prescribed.
PMID- 9762730
TI - Evaluation of nurses' errors associated in the preparation and administration of
medication in a pediatric intensive care unit.
AB - The objectives of this study were to determine the frequency and the types of
errors which occur regarding the preparation and the administration of medication
and to identify the main causes of these errors in a pediatric intensive care
unit (PICU) at the University Hospital in Lausanne (Switzerland). In this
prospective study, based on the observation of nurses' activities, the data were
collected over a period of 10 weeks. The error classification was based on the
American Society of Hospital Pharmacy (ASHP) definitions. The frequency of errors
was calculated as the sum of all noted errors divided by the total administered
drugs, plus the sum of all omitted drugs, multiplied by 100. The sum of all given
doses plus all omitted doses gives the 'total opportunity for errors'. This total
was 275 and the total frequency of errors was 26.9%. The most frequent errors
were wrong-time errors (32.4%), wrong-administration-technique errors (32.4%) and
preparation errors (23.0%). In relation with other studies conducted under
comparable conditions, a lesser number of omissions and wrong-time errors were
observed. On the contrary, administration-technique and dose-preparation errors
were more frequent at our hospital. A program of systematic assistance and survey
by professional pharmacists could improve the quality of the preparation and
administration of medication in the PICU.
PMID- 9762731
TI - A multi-level model of data with repeated measures of the effect of lamb
diarrhoea on weight.
AB - Over a 1-year period, data were collected from three flocks of sheep. A total of
213 lambs were examined routinely from birth to 32 kg (2178 examinations in
total). Diarrhoea was seen in lambs of all ages but did not appear to make them
systemically ill. The effect of diarrhoea on lamb weight was investigated using
MLn, a multi-level modeling program. The data were set at three hierarchical
levels: level one, the repeated examinations on each lamb; level two, the lamb;
and level three, the litter. Age, the quadratic of age, litter size, sex and farm
of origin, all had significant effect on the weight of the lambs. There was also
significant random variation in examinations within lambs, between individual
lambs and between litters of lambs. There was a reduction in absolute weight of
lambs for each week until four weeks after an episode of diarrhoea.
PMID- 9762732
TI - Prevalence of and risk factors for shedding of Cryptosporidium parvum in Holstein
Freisian dairy calves in central Mexico.
AB - A total of 31 dairy farms from three states in central Mexico were selected for
this study in order to determine the prevalence of and risk factors for
Cryptosporidium parvum shedding in young Holstein Freisian calves. Fecal samples
were obtained once from each calf for acid-fast staining for detection of C.
parvum oocysts. Information on each calf and on each dairy's management practices
regarding the maternity pen, calf hutches and calf feeding was obtained by
personal interview using a standardized questionnaire. Of the 31 dairies, 29 had
one or more calves shedding C. parvum oocysts. The overall point prevalence was
25% (128/512). Dairy calves from the states of Hidalgo, Jalisco, and Mexico had
overall point prevalences of 28% (51/185), 29% (33/112) and 20% (44/215),
respectively. Day of age was strongly associated with the risk of shedding C.
parvum oocysts, with a maximum risk of shedding at approximately 15 days of age.
Using mixed-effects logistic regression with herd as the random effect, feeding
starter grain to calves, sweeping out the maternity pen, and using hay bedding in
the maternity pen were significantly associated with increased odds of shedding
C. parvum oocysts. We speculate that the association between feeding starter
grain to calves and the higher odds of shedding C. parvum is linked to an
increased duration rather than a higher incidence density of shedding. In
addition, the association between sweeping the maternity pen and the increased
odds of shedding C. parvum may be attributable to dairy personnel using the same
broom for cleaning calf hutches and the maternity pen, thereby cross
contaminating oocysts from infected to newborn calves.
PMID- 9762733
TI - A review of the feeding-health-production complex in a dairy herd.
AB - Diseases may be an important link in the relationship between feeding and
production in a dairy herd. The low frequency of relevant disorders calls for
studies on survey data on a large population. However, this approach suffers from
lack of detailed herd feeding data and consequently only few have studied feeding
as a risk factor for disease. Therefore, we reviewed information from various
studies to integrate what is known of the feeding-health-production complex in a
dairy herd. The need for putting together information from different sources, the
herd effects, and the fact that the effect of one factor cannot be kept constant
for investigation in a real-life dynamic herd call for a conceptual model as a
framework for the review. The complexity is minimized to allow the representation
of important elements. Within-cow relationships (such as feeding-disease
relationships, disease interrelationships, and disease-production relationships)
are reviewed specifically for: ketosis, milk fever, displaced abomasum, acidosis,
sole ulcers and laminitis, and bloat. The major feeding management factors
involved are concentrate feeding (level and how it is provided) and
overconditioned cows. Disease interrelationships are important. Generalization of
production loss from diseases is complicated due to the variety of estimates and
measures used.
PMID- 9762734
TI - Multiple change-point analysis applied to the monitoring of Salmonella prevalence
in Danish pigs and pork.
AB - In the nation-wide Salmonella Control Program in Denmark, the occurrence of
Salmonella enterica in pork, pigs at slaughter and herds is monitored. The
objective of the present study was to retrospectively evaluate changes in sero
prevalence of meat juice samples and in the occurrence of Salmonella enterica in
pork in 1995 and 1996. Three sets of data were used in this work: (1) serological
test results of meat juice samples from pigs at slaughter (approximately 14000
samples per week); (2) bacteriological test results of pork (approximately 550
samples per week); and (3) data on the salmonella level of all Danish herds with
an expected kill of over 100 pigs per year. The change-point analysis was applied
to detect the change-points that divided the study period into intervals in which
the prevalence was constant and to estimate the average prevalences in those
intervals. Progress in the Danish Salmonella Control Program was visualised when
using the results of the change-point analysis (1995-96) as baseline prevalences
and compared with the current year (1997). The change-point analysis provided an
indication of a seasonal pattern in salmonella occurrence with lower sero
prevalence in summer than in winter. The sero-prevalence (percent positive meat
juice samples) might be a better predictor of prevalence in pork than the
proportion of herds with moderate or high sero-prevalence.
PMID- 9762735
TI - Proportional morbidity rates of enteropathogens among diarrheic dairy calves in
central Spain.
AB - Faecal samples from 218 diarrheic dairy calves in 65 dairy herds, selected by
convenience, were screened for the presence of rotavirus, coronavirus,
Cryptosporidium spp., F5+ Escherichia coli and Salmonella spp. Animals surveyed
were from 1 to 30 days old. Cryptosporidium and rotavirus were the most commonly
detected agents (52.3% and 42.7% of the samples positive, respectively). F5+ E.
coli was detected in the faeces of 11.9% of the calves and bovine coronavirus was
detected in the faeces of 7.3% of the calves. Salmonella spp. was only found in
the faeces of two calves (0.9%). Mixed infections with two or more agents
occurred in 28% of the calves. Concurrent infection of rotavirus and
Cryptosporidium was found in 21.6% of the calves. Two tests were used for the
detection of rotavirus (a commercial ELISA and PAGE), F5+ E. coli (ELISA and
bacterial culture) and Cryptosporidium (ELISA and microscopy). The validity of
the commercial ELISA for the detection of rotavirus, F5+ E. coli and
Cryptosporidium in faeces from diarrheic calves was evaluated using PAGE,
bacterial culture and microscopy as gold standard, respectively. The ELISA showed
a very low sensitivity (28.6%) for the detection of F5+ E. coli compared to
bacterial culture.
PMID- 9762736
TI - Epidemiologic features of equine Leptospira interrogans of human significance.
AB - Leptospirosis is a zoonotic bacterial disease caused by Leptospira interrogans.
There is a serologic evidence that horses are exposed to L. interrogans and, as a
shedder of these organisms, can be a threat to humans. We examined risk factors
associated with the risk of testing seropositive to three L. interrogans serovars
(L. icterohaemorrhagiae, L. grippotyphosa, and L. canicola) in the horses of New
York State, in order to understand the epidemiology of the disease and suggest
strategies to control and prevent equine leptospirosis. To carry out this study,
blood samples were collected from a random sample of 2551 horses and tested for
the presence of antibodies to the above serovars using the microscopic
agglutination test. Samples with a titer $100 were considered positive. Clinical
and demographic data were collected on each horse, the farms' management
practices and ecology. Logistic regression analysis was used to develop a
multivariate indexing system and to identify factors significantly associated
with the risk of leptospirosis. Four indices were developed based on the possible
sources of exposure: rodent exposure index; wildlife exposure index; soil and
water index; and management index. The soil and water index was significantly
associated with the risk of exposure to all three serovars. Management was
positively associated with L. icterohaemorrhagiae and L. canicola. Density of
horses turned out together was positively associated with the risk of exposure to
L. grippotyphosa. We concluded that indirect exposure of horses to L. interrogans
through contaminated soil and water appears to be significantly associated with
the risk of exposure to all three serovars. Management appears to play an
important role in the exposure to L. interrogans. Modification of management
practices might reduce the horses' risk of exposure and hopefully minimize the
human hazards.
PMID- 9762738
TI - A biomechanical study of anterior thoracolumbar screw fixation.
AB - STUDY DESIGN: The pullout strength of unicortical and bicortical screws in
thoracic and lumbar vertebral bodies was measured as a function of bone mineral
density. OBJECTIVES: To determine the influence of bone mineral density and screw
insertion technique on the stability of anterior thoracolumbar spine screw
fixation. SUMMARY OF BACKGROUND DATA: No previous study has addressed the
specific technique of screw insertion or stability of screw fixation in the
anterior spine. METHODS: Fifty-one human thoracic vertebral bodies were tested in
pullout with 6.55-mm cancellous screws inserted using unicortical and bicortical
techniques. RESULTS: Pullout force increased exponentially with increasing bone
mineral density for unicortical and bicortical screws. Bicortical screws were
significantly stronger in resisting pullout than unicortical screws. CONCLUSION:
Advancing an anterior vertebral body screw to engage the second cortex increases
resistance to pullout by 25-44%, depending on vertebral bone mineral density. The
difference in resistance between unicortical and bicortical techniques was
smaller in specimens with low mineral densities.
PMID- 9762737
TI - A new culture system to study the metabolism of the intervertebral disc in vitro.
AB - STUDY DESIGN: This study determined whether entrapment of a rabbit intervertebral
disc in alginate gel helped to promote the retention of normal metabolic
activities by the nucleus pulposus and anulus fibrosus in tissue culture.
OBJECTIVES: To establish an in vitro culture system to study the metabolism of
the intervertebral disc as a whole integral organ. SUMMARY OF BACKGROUND DATA: In
vitro studies of the metabolism of intervertebral discs have been scarce because
of the difficulties involved in maintaining the integrity of the tissues,
especially that of the nucleus pulposus, in culture medium. METHODS: Rabbit
intervertebral discs were embedded in alginate gel and maintained in culture for
as long as 1 month. At weekly intervals, experiments were performed to measure
the rate of proteoglycan synthesis and to characterize proteoglycans newly
synthesized by cells in the anulus fibrosus and nucleus pulposus. In addition, at
these same time intervals, the contents of sulfated proteoglycans, antigenic
keratan sulfate, hyaluronan, and collagen in these two intervertebral disc
tissues were measured to evaluate tissue integrity. Intervertebral discs cultured
in medium alone were used as controls and analyzed in parallel. RESULTS: The
anulus fibrosus and nucleus pulposus of intervertebral discs cultured in alginate
gel sustained a higher rate of proteoglycan synthesis and maintained a higher
content of extracellular matrix components than the respective controls at all
times. CONCLUSIONS: This new alginate tissue culture system should prove useful
for studying the metabolism of whole intervertebral discs.
PMID- 9762739
TI - A biomechanical study of Jefferson fractures.
AB - STUDY DESIGN: Fifteen specimens of the first cervical vertebra were tested by the
application of pure tensile forces to failure. Seven specimens had intact
transverse ligaments, and eight had transection of the transverse ligament before
testing. Specimens were tested to failure by the rapid application of laterally
directed tensile force to the ring; this force then was exerted through the
lateral masses to simulate the mechanism of injury for this fracture as proposed
by Jefferson. OBJECTIVES: To measure the biomechanical characteristics of the C1
ring, including the fracture patterns created with tensile loading, and to
describe the influence of the transverse ligament on the behavior of the ring as
it failed under tension. SUMMARY OF BACKGROUND DATA: Jefferson fractures have
been reproduced in the laboratory by subjecting head and neck preparations to
axial load. However, no previous detailed biomechanical studies of the fracture
characteristics of the isolated C1 vertebra have been reported. METHODS:
Specimens were tested to failure by rapid application of laterally directed
tensile forces to the ring. RESULTS: Eleven two-part and three three-part
fractures occurred. The mean tensile strength of the atlas was found to be 2,280
N. The average deformation required to fracture the C1 ring was 1.57 mm. The
total energy absorbed by the ring averaged 1.99 N-m. There was no statistically
difference between those specimens with the transverse ligament intact and those
without a transverse ligament. CONCLUSIONS: The results of this study show that
fractures of the C1 ring of greater than two parts can occur with pure tensile
loading. The ring will fracture with as little as 1 mm of deformation.
PMID- 9762740
TI - Functional outcome of surgically and conservatively managed dens fractures.
AB - STUDY DESIGN: Fifty-seven patients with dens fractures were identified from 1986
to 1996 at the authors' institution. Forty-six were available for reevaluation by
two independent observers with a mean follow-up period of 26 months. OBJECTIVE:
To determine by age and fracture type which treatment regimen provided the best
functional outcome in patients with dens fractures. SUMMARY OF BACKGROUND DATA:
There were no Type I fractures, but there were 37 Type II and 20 Type III
fractures. Twenty-nine patients were under 60 years of age, and 28 were 60 years
and older. Six patients had been treated by immediate C1-C2 posterior fusion, and
five received treatment with a Philadelphia collar only. Forty-six patients were
placed in a halo thoracic immobilizer with a symptomatic nonunion rate of 19.5%.
These patients ultimately required posterior cervical fusion. METHODS: Final
functional outcome, level of pain, and cervical range of motion were all
statistically evaluated using multivariate analysis (Wilcoxon's two-sample test).
The influence of age, fracture type, and treatment method were determined.
RESULTS: There were no cases of short- or long-term neurologic deterioration in
any of the patients in the study group. There was a significantly higher rate of
complications associated with halo use in the older population. Pain scores were
higher in Type II fractures and in patients treated conservatively with halo
immobilization, especially those patients over 60 years of age. No statistically
significant difference in these parameters were found. Older patients treated
surgically did not have a better functional outcome score than those treated
nonoperatively (P < 0.8). Persons over 60 years of age treated in a halo had a
significantly (P < 0.05) decreased range of motion when compared with younger
patients treated similarly. CONCLUSION: Patients over 60 years of age with a dens
fracture had a higher complication rate and lower cervical range of motion when
treated conservatively with a halo. Final functional outcome and overall pain
levels, however, did not differ significantly by age group or treatment modality.
PMID- 9762741
TI - The ability of lumbar medial branch blocks to anesthetize the zygapophysial
joint. A physiologic challenge.
AB - STUDY DESIGN: Randomized, controlled, single blinded study. OBJECTIVES: To
determine the physiologic effectiveness of lumbar medial branch blocks. SUMMARY
OF BACKGROUND DATA: Zygapophysial joint pain can be diagnosed by anesthetization
of the joint or its nerve supply (the medial branch divisions of the dorsal
rami). The physiologic effectiveness of lumbar medial branch blocks has been
assumed but not proven. METHODS: Eighteen asymptomatic individuals were randomly
assigned to either L4-L5 or L5-S1 zygapophysial joint injections with contrast
medium until capsular distention elicited pain without extracapsular contrast
spread. One week later, 15 blinded individuals underwent two randomized saline or
2% lidocaine medial branch injections that correlated to the innervation of the
previously injected joint. Medical branch injections were performed such that
inadvertent venous uptake was avoided in 14 individuals. Thirty minutes after
medial branch injections, these 14 individuals underwent repeat capsular
distention of the same zygapophysial joint provoked the prior week in an attempt
to elicit another painful response. RESULTS: All five control individuals who
received saline medial branch injections felt pain on repeat capsular distention.
Nine individuals received 2% lidocaine medial branch blocks; eight felt no pain,
and one felt pain on repeat capsular distention. CONCLUSIONS: There was a
significant effect of 2% lidocaine (versus saline) medial branch injections on
anesthetization of the zygapophysial joint when venous uptake was avoided during
these injections. When properly performed, lumbar medial branch blocks
successfully inhibit pain associated with capsular distention of the lumbar
zygapophysial joints at a rate of 89%.
PMID- 9762742
TI - Regional correspondence between the ventral portion of the lumbar intervertebral
disc and the groin mediated by a spinal reflex. A possible basis of discogenic
referred pain.
AB - STUDY DESIGN: Lumbar peripheral nerves were examined to determine whether they
were responsive to electrical stimulation of the ventral portion of the lumbar
disc in anesthetized rats. OBJECTIVES: To confirm by electrophysiologic means the
neural correspondence between the ventral portion of the lumbar disc and the
groin. SUMMARY OF BACKGROUND DATA: Patients with a degenerated lumbar disc
occasionally report groin pain. However, its pathogenesis has not been
investigated. The authors of the current study found that chemical stimulation of
the ventral portion of rat lumbar disc caused cutaneous plasma extravasation in
the groin, and thereby hypothesize the neural relation between the lumbar disc
and the groin. METHODS: The ventral portion of rat L5-L6 disc was electrically
stimulated, and the elicited action potentials were recorded from the
iliohypogastric, genitofemoral, lateral femoral cutaneous, sural, and sciatic
nerves. The roles of the lumbar sympathetic trunks and spinal cord in the
generation of the action potentials were examined. RESULTS: Action potentials
were elicited principally in the genitofemoral nerve; the action potentials of
the genitofemoral nerve were not influenced by transection of the cervical spinal
cord, whereas they disappeared immediately after death, which indicates that they
are induced by a spinal reflex. The action potentials were reduced considerably
after destruction of the lumbar sympathetic trunks, suggesting that they comprise
an afferent path of the reflex. CONCLUSIONS: The ventral portion of the lumbar
disc had spatial relation to the groin area via a spinal reflex. Such a relation
suggests that a disorder in the ventral portion of the lumbar disc may be a
possible source of groin referred pain.
PMID- 9762743
TI - The Saskatchewan health and back pain survey. The prevalence of low back pain and
related disability in Saskatchewan adults.
AB - STUDY DESIGN: Population-based, cross-sectional, mailed survey. OBJECTIVES: To
determine the lifetime, 6-month period, and point prevalence of low back pain and
its related disability among Saskatchewan adults and to investigate the presence
and strength of selective response bias. SUMMARY OF BACKGROUND DATA: There have
been many reports of the prevalence of low back pain in different populations,
and the estimates vary widely depending on case definition. However, most studies
fail to differentiate between trivial and disabling back pain, which raises the
issue of the usefulness of these estimates. No studies have yet documented the
prevalence of graded low back pain severity and its related disability in a North
American, general, population-based survey. METHODS: The Saskatchewan Health and
Back Pain Survey was mailed to a probability sample of 2184 Saskatchewan adults
between 20 and 69 years of age. Fifty-five percent of the eligible population
responded to the survey. Respondents were compared with nonrespondents, and the
presence of selective response bias by back pain status was investigated by wave
analysis. The point and lifetime prevalence of low back pain was determined by
simple questions, and the 6-month period prevalence of low back pain was
determined by the Chronic Pain Questionnaire. All estimates were age standardized
to the Saskatchewan population. RESULTS: The authors estimate that at the time of
the survey 28.4% (95% confidence interval, 25.6-31.1) of the Saskatchewan adult
population were experiencing low back pain, and 84.1% (95% confidence interval,
81.9-86.3) had experienced it during their lifetime. Overall, 48.9% (95%
confidence interval, 45.9-52.0) of the population had experienced low
intensity/low-disability low back pain in the previous 6 months, 12.3% (95%
confidence interval, 10.3-14.4) had experienced high-intensity/low-disability low
back pain, and an additional 10.7% (95% confidence interval, 8.8-12.5) had
experienced high-disability low back pain in the previous 6 months. There was
little variation in the estimates over age groups, but women experienced more
high-disability back pain than men. There was no evidence of selective response
bias by low back pain status in the survey. CONCLUSION: Low-intensity/low
disability low back pain is a common problem in the general population.
Approximately 11% of the adult population studied had been disabled by low back
pain in the previous 6 months.
PMID- 9762744
TI - Degenerative displacement of lumbar vertebrae. A 25-year follow-up study in
Framingham.
AB - STUDY DESIGN: The authors assessed degenerative lumbar displacement in a
population-based cohort of 217 men and 400 women who had lateral lumbar
radiographs performed at the mean age of 54 years and again at 79 years, and who
had completed interviews on back symptoms and functional performance in
connection with the follow-up examination. OBJECTIVES: To assess the prevalence
and incidence of degenerative slippage and its association with back pain and
physical disability. SUMMARY OF BACKGROUND DATA: Degenerative displacement of
lumbar vertebrae may cause instability, nerve root compression, and spinal
stenosis. Its incidence in the older population and association with back pain
and disability are unknown. METHODS: The authors assessed the prevalence and
incidence of degenerative slippage from lateral lumbar radiographs performed 25
years apart and its association with back pain and physical disability from
interviews performed in connection with the follow-up examination. RESULTS: At
the follow-up examination, 23 (12%) men and 100 (25%) women had developed
degenerative slippage exceeding 3 mm; two of them had this already at the
baseline. A forward displacement was found in 8 men and 76 women (P < 0.0001 for
difference between the genders) and a backward one in 16 men and 35 women. On
average, forward slip was 18% +/- 5.5, and backward slip, 15% +/- 4.0 of the
anteroposterior diameter of the vertebra below. At the time of the second lumbar
radiograph, 39 (32%) of the subjects with slippage, compared with 90 (19%) of the
controls, had pain, aching, or stiffness in their back on most days (P = 0.001).
After adjustment for endplate sclerosis, which was also related to pain (P =
0.015), slippage still had association with daily back symptoms (P = 0.009).
However, subjects with slippage had not experienced more back symptoms during the
preceding year or in earlier ages of life, and they did not report more
disability than the controls. CONCLUSIONS: Degenerative displacement of lumbar
vertebrae is common in an older population and is associated with increased
prevalence of daily back symptoms. However, two thirds of the subjects with
degenerative displacement do not report ongoing back symptoms, and the disorder
is also unrelated to long-term back pain and physical disability.
PMID- 9762745
TI - One-year follow-up comparison of the cost and effectiveness of chiropractic and
physiotherapy as primary management for back pain. Subgroup analysis, recurrence,
and additional health care utilization.
AB - STUDY DESIGN: A randomized trial was conducted in which patients with back and
neck pain, visiting a general practitioner, were allocated to chiropractic or
physiotherapy. OBJECTIVES: To compare outcome and costs of chiropractic and
physiotherapy as primary treatment for patients with back and neck pain, with
special reference to subgroups, recurrence rate, and additional health care use
at follow-up evaluation 12 months after treatment. SUMMARY OF BACKGROUND DATA:
Earlier studies on the effect of spinal manipulation have shown inconsistent
results. Mostly they include only short-term follow-up periods, and few cost
effectiveness analyses have been made. METHODS: A group of 323 patients aged 18
60 years who had no contraindications to manipulation and who had not been
treated within the previous month were included. Outcome measures were changes in
Oswestry scores, pain intensity, and general health; recurrence rate; and direct
and indirect costs. RESULTS: No differences were detected in health improvement,
costs, or recurrence rate between the two groups. According to Oswestry score,
chiropractic was more favorable for patients with a current pain episode of less
than 1 week (5%) and physiotherapy for patients with a current pain episode of
greater than 1 month (6.8%). Nearly 60% of the patients reported two or more
recurrences. More patients in the chiropractic group (59%) than in the
physiotherapy group (41%) sought additional health care. Costs varied
considerably among individuals and subgroups; the direct costs were lower for
physiotherapy in a few subgroups. CONCLUSIONS: Effectiveness and costs of
chiropractic or physiotherapy as primary treatment were similar for the total
population, but some differences were seen according to subgroups. Back problems
often recurred, and additional health care was common. Implications of the result
are that treatment policy and clinical decision models must consider subgroups
and that the problem often is recurrent. Models must be implemented and tested.
PMID- 9762746
TI - Sequential or simultaneous, same-day anterior decompression and posterior
stabilization in the management of vertebral osteomyelitis of the lumbar spine.
AB - STUDY DESIGN: A retrospective clinical study of patients with vertebral
osteomyelitis of the lumbar spine necessitating surgical treatment. All patients
underwent sequential (same-day) or simultaneous anterior decompression and
posterior stabilization of the involved vertebrae. OBJECTIVE: To evaluate the
efficacy and clinical out-come of sequential or simultaneous anterior and
posterior surgical approaches in the management of vertebral osteomyelitis of the
lumbar spine. SUMMARY OF BACKGROUND DATA: Anterior approach alone and staged
anterior decompression and posterior stabilization have been advocated as the
surgical treatment methods of choice for patients with vertebral osteomyelitis of
the lumbar spine. The drawbacks of the latter management plan are the necessity
to use external support or the delayed patient mobilization and the need for
additional anesthesia and surgical trauma. Sequential (same-day) anterior and
posterior approaches are used regularly in the surgical management of scoliosis
and other spinal deformities. It would appear advantageous to also use the same
strategy (i.e., combined same-day double approaches) in the management of
vertebral osteomyelitis of the lumbar spine. METHODS: Ten consecutive patients
who had a diagnosis of vertebral osteomyelitis of the lumbar spine underwent
combined (same-day) anterior and posterior approaches either in a sequential or
simultaneous manner. Indications for surgery included neurologic deficit, abscess
formation, instability with localized kyphosis formation, and failure of
nonoperative treatment. Patients were evaluated clinically and radiographically
after surgery. RESULTS: All 10 patients had uneventful surgery. Only one patient
required a second surgical procedure because of expulsion of the anterior bone
graft and pull-out of instrumentation. All patients were mobilized within the 2
days immediately after surgery. At the mean follow-up examination 30 months after
surgery, all patients had regained their motor function and prior ambulatory
status. CONCLUSIONS: Patients with lumbar osteomyelitis necessitating surgery can
undergo combined, same-day surgery either in a sequential or simultaneous manner.
This is a safe and efficient way to control the infection and stabilize the
affected segments, allowing for early mobilization of these sick elderly
patients.
PMID- 9762747
TI - L5 root compression caused by degenerative spinal stenosis of the L1-L2 and L2-L3
spaces.
AB - STUDY DESIGN: A severe bilateral L5 root lesion associated with spinal stenosis
at L1-L2 and L2-L3 is described. OBJECTIVE: To describe clinical findings and the
difficulty in obtaining a correct diagnosis of L5 Root Compression. SUMMARY OF
BACKGROUND DATA: The disorder reported in this study has not been reported
previously. Only one similar case has been described in the literature: an L5
root compression at L1-L2 caused by disc herniation. METHODS: Diagnosis was
obtained by using computed tomography scanning, magnetic resonance imaging, and
computed tomography myelography. The findings at L5-S1 were minimal to justify
the patient's clinical symptoms, but a detailed study of the upper levels
revealed spinal stenosis at L1-L2 and L2-L3, which could have been causing L5 and
S1 root compression. A decompressive laminectomy and partial facetectomy in both
levels were performed. RESULTS: The patient's pain and claudication disappeared,
and clinical symptoms associated with the right L5 root improved. The left L5
root deficit remained stable. CONCLUSION: An unusual case of L5 root compression
caused by degenerative stenosis of L1-L2 and L2-L3 is described.
PMID- 9762749
TI - Costal osteochondroma. A rare cause of spinal cord compression.
AB - STUDY DESIGN: Report of a rare cause of spinal cord compression: costal
osteochondroma. OBJECTIVE: To describe a very rare cause of spinal cord
compression, costal osteochondroma, which was present in a 16-year-old girl with
a history of hereditary multiple exostoses. SUMMARY OF BACKGROUND DATA: Only four
cases of expansion of costal osteochondroma into the spinal canal through an
intervertebral foramen have been reported previously. METHODS AND RESULTS: The
origin of the osteochondroma at the head of the right 12th rib, the invasion of
the spinal canal through the right T12-L1 intervertebral foramen, and the
compression of the spinal cord were shown on computed tomography and magnetic
resonance imaging. The exact extent of the osteochondroma, particularly the
cartilage cap, was delineated accurately by magnetic resonance imaging. Complete
excision followed by full recovery occurred 19 months after surgery. CONCLUSION:
Magnetic resonance imaging is the preferred method of investigation in cases of
osteochondroma related to spine, because it allows for better pre-operative
planning and helps to prevent incomplete excision of the tumor.
PMID- 9762748
TI - Lumbar intervertebral disc involvement in chronic lymphocytic leukemia. A case
report.
AB - STUDY DESIGN: Report of a patient with a rare location of a solid chronic
lymphocytic leukemic mass of an intervertebral lumbar disc. OBJECTIVES: To
illustrate the previously undescribed discovertebral involvement of chronic
lymphocytic leukemia and to discuss the diagnostic difficulties. SUMMARY OF
BACKGROUND DATA: Chronic lymphocytic leukemia primarily involves lymph nodes,
spleen, liver, and bone marrow. Bone lesions are rare in chronic lymphocytic
leukemia and usually consist of areas of osteopenia. Spinal involvement in
chronic lymphocytic leukemia is rare, and only two cases of spinal cord
compression attributable to an extradural solid mass composed of leukemic cells
have been reported. Intervertebral disc involvement in chronic lymphocytic
leukemia has not been reported previously. METHODS: The clinical findings,
radiographs, histology, treatment, and follow-up results are presented. RESULTS:
Radiographs and magnetic resonance imaging studies showed partial collapse of
vertebrae L2 and L3, with destruction and protrusion of the intervertebral disc
L2-L3 with dura compression. Treatment consisted of radiotherapy followed by en
bloc resection of vertebrae L2 and L3 stabilized with stackable cages and
anterior fixation with Kaneda bars. Intervertebral disc infiltration with
leukemic cells of B-cell origin was confirmed through histologic examination and
immunohistochemical studies of a biopsy and resection specimen. Twenty months
after treatment the patient was still in remission and fully mobilized.
CONCLUSIONS: Intervertebral disc involvement in cases of chronic lymphocytic
leukemia is rare. Its presence should be considered in patients with back pain
and neurologic symptoms who had been treated for this form of leukemia in the
past. Differentiation with infectious spondylodiscitis can be difficult.
Histology is necessary to confirm diagnosis.
PMID- 9762751
TI - Intraoperative electromyography during thoracolumbar spinal surgery.
AB - Intraoperative electromyography can provide useful information regarding
lumbosacral nerve root function during thoracolumbar spinal surgery. Free-running
electromyography provides continuous feedback regarding the location and
potential for surgical injury to the lumbosacral nerve roots within the operative
field. Stimulus-evoked electromyography can confirm that transpedicular
instrumentation has been positioned correctly within the bony cortex. However,
electromyography has a number of potential limitations, which are discussed in
this article along with improved methods to increase the overall efficacy of
intraoperative electromyography, including: 1) Electromyography is sensitive to
blunt lumbosacral nerve root irritation or injury, but may provide misleading
results with "clean" nerve root transection. 2) Electromyography must be recorded
from muscles belonging to myotomes appropriate for the nerve roots considered at
risk from surgery. 3) Electromyography can be effective only with careful
monitoring and titration of pharmacologic neuromuscular junction blockade. 4)
When transpedicular instrumentation is stimulated, an exposed nerve root should
be stimulated directly as a positive control whenever possible. 5) Pedicle holes
and screws should be stimulated with single shocks at low-stimulus intensities
when pharmacologic neuromuscular blockade is excessive. 6) Chronically compressed
nerve roots that have undergone axonotmesis (wallerian degeneration) have higher
thresholds for activation from electrical and mechanical stimulation. 7) Hence,
whenever axonotmetic nerve root injury is suspected, the stimulus thresholds for
transpedicular holes and screws must be specifically compared with those required
for the direct activation of the adjacent nerve root (and not published guideline
threshold values).
PMID- 9762750
TI - Herophilus of Alexandria (325-255 B. C.). The father of anatomy.
AB - Herophilus (325-255 B. C.) is one of the group that has been called the great
Greek physicians. All members of this group lived during the last 400 years of
Greek intellectual leadership and the first 200 years of Roman domination.
Herophilus was born in the Greek town of Chalcedon. He received his medical
training under Praxagoras, a famous physician and anatomist who taught at the
Hippocratean medical school on the island of Cos (Kos). He moved to Alexandria,
Egypt, as a young man and lived there for the rest of his life. With his younger
contemporary, Erasistratus, he did the first ever scientific human cadaveric
dissections for a short period of no more than 30-40 years. Human dissection then
was forbidden and was not allowed again for 1800 years. It seems that only these
two physicians ever performed human dissection until the Renaissance, around 1530
A. D. The anatomic and physiologic discoveries of Herophilus were phenomenal. As
Hippocrates is called the Father of Medicine, Herophilus is called the Father of
Anatomy. Most would argue that he was the greatest anatomist of antiquity and
perhaps of all time. The only person who might challenge him in this assessment
is Vesalius, who worked during the 16th century A. D.
PMID- 9762752
TI - Saskatchewan health and back pain survey.
PMID- 9762753
TI - Lumbar lordosis: effects of sitting and standing.
PMID- 9762754
TI - Postoperative pain control after lumbar spine fusion.
PMID- 9762755
TI - Observations made during school screening for scoliosis in Greece.
PMID- 9762756
TI - Milk quality survey to include Mycobacterium paratuberculosis.
PMID- 9762757
TI - Effects of quarantine on cats and their owners.
AB - The effects of quarantine on 16 cats and their owners were assessed by means of
four questionnaires completed by the owners at the beginning of their cat's stay
in quarantine, three months later, and two weeks and three months after the cats
left quarantine. Changes in body condition were evident in two-thirds of the cats
during and at the end of quarantine but not three months later. Mid-way through
quarantine, the owners considered their cats were less attached to them, less
relaxed, more excitable, more aggressive, more nervous and less playful than
before quarantine. When they left quarantine the cats were friendlier, more
affectionate and more timid, and three months later they were more affectionate,
more nervous and more vocal than before quarantine. When they left quarantine and
three months later the cats spent more time with their owners than before
quarantine. Most owners visited their cats once or twice a month; the location of
the cattery and the limited opening hours restricted the number of visits they
made.
PMID- 9762758
TI - Comparison of pethidine, buprenorphine and ketoprofen for postoperative analgesia
after ovariohysterectomy in the cat.
AB - Sixty cats which underwent an ovariohysterectomy were randomly allocated into
four treatment groups. One group (controls) received no analgesics
postoperatively, and the others received either a single dose of buprenorphine
(0.006 mg/kg) intramuscularly, or pethidine (5 mg/kg) intramuscularly, or
ketoprofen (2 mg/kg) subcutaneously. The analgesia obtained after each treatment
was assessed by three measures. There were significant differences between the
groups both for the requirement for intervention analgesia (P = 0.0008) and for
the overall clinical assessment (P = 0.0003) with ketoprofen requiring least
intervention analgesia and having the best overall clinical assessment, followed
by buprenorphine then pethidine. The control group required the most intervention
analgesia and had the worst overall clinical assessment. Visual analogue scale
scoring for pain produced significant differences between the groups from one
hour after the operation, with the cats which were given ketoprofen tending to
have lower pain scores than the other groups.
PMID- 9762759
TI - Inhibition of antigen-induced cutaneous responses of ponies with insect
hypersensitivity by the histamine-1 receptor antagonist chlorpheniramine.
AB - A whole-body extract of Culicoides impunctatus induced a biphasic increase in
oedema formation in ponies with insect hypersensitivity, with maxima after one
and eight hours. The Culicoides antigen did not induce similar responses in
ponies with no previous history of the disease. In insect-hypersensitive ponies
the local administration of chlorpheniramine (12 micrograms) completely inhibited
oedema formation in response to histamine (0.04 microgram) and to Culicoides
antigen (0.5 microgram) at one hour, and the response to Culicoides antigen at
eight hours was inhibited by 63 per cent. Chlorpheniramine also partially
inhibited the accumulation of eosinophils and neutrophils induced by Culicoides
antigen after two hours.
PMID- 9762760
TI - Persistence of the activity of topical ivermectin against biting lice (Bovicola
bovis).
AB - To assess the persistence of the activity of topical ivermectin against a natural
challenge with biting lice (Bovicola bovis), 90 mixed-breed cattle that had been
treated to remove lice, were blocked by bodyweight within sex and randomly
allocated to three treatments: untreated control, doramectin at 200 micrograms/kg
by subcutaneous injection, and ivermectin at 500 micrograms/kg by topical
application. Forty-five pens were blocked into three groups of 15, and the blocks
of pens were randomly allocated to three 14-day challenge periods starting 21, 28
and 35 days after treatment. There were five pens per treatment for each
challenge period, and one B bovis-infested donor calf was introduced into each
pen containing two principal calves at the start of the challenge period for that
block of pens. The calves were examined thoroughly for B bovis seven, 14 and 21
days after the introduction of the donors. There were no significant differences
between the control and doramectin groups for the numbers of animals infested, or
the geometric mean louse counts at the final examination for any of the challenge
periods. At the final examination for each challenge period, the louse counts of
the cattle treated with topical ivermectin were all zero, and significantly (P <
0.05) fewer cattle treated with topical ivermectin were infested than either the
controls or cattle treated with doramectin.
PMID- 9762761
TI - Laryngeal rhabdomyoma in a golden retriever.
AB - A three-year-old male golden retriever had had progressive dyspnoea, exercise
intolerance, stridor, and a modified bark for five months. A mass 2 cm in
diameter was present dorsal to the right side of the larynx. Histological
examination revealed cross-striations in some elongated cells, consistent with a
diagnosis of rhabdomyoma, a diagnosis which was confirmed by positive
immunohistochemical staining for myoglobin and desmin. The mass could not be
removed without total laryngectomy and a permanent tracheostomy and the dog was
euthanased.
PMID- 9762762
TI - Influence of concurrent BVDV infection on the IgM response of calves
experimentally infected with bovine respiratory syncytial virus.
PMID- 9762763
TI - Natural reactivation of caprine herpesvirus 1 in latently infected goats.
PMID- 9762764
TI - Congenital stenosis of the preputial orifice in a dog.
PMID- 9762765
TI - BVPA guidelines on antimicrobial resistance.
PMID- 9762767
TI - Importance of personal insurance.
PMID- 9762766
TI - Recall of Droplix.
PMID- 9762768
TI - Homoeopathy and clinical trials.
PMID- 9762769
TI - 'Twitchiness' in miniature wirehaired dachshunds.
PMID- 9762770
TI - What is your diagnosis?
PMID- 9762771
TI - Being more positive about negative ventilation?
PMID- 9762772
TI - Immunoglobulin A in asthma: friend or foe?
PMID- 9762773
TI - Negative pressure ventilation versus conventional mechanical ventilation in the
treatment of acute respiratory failure in COPD patients.
AB - This case-control study was aimed to evaluate the effectiveness of negative
pressure ventilation (NPV) versus conventional mechanical ventilation (CMV) for
the treatment of acute respiratory failure (ARF) in patients with chronic
obstructive pulmonary disease (COPD) admitted to a respiratory intermediate
intensive care unit (RIICU) and four general intensive care units (ICU). Twenty
six COPD patients in ARF admitted in 1994-95 to RIICU and treated with NPV
(cases) were matched according to age (+/-5 yrs), sex, causes triggering ARF,
Acute Physiology and Chronic Health Evaluation (APACHE) II score (+/- 5 points),
pH (+/-0.05) and arterial carbon dioxide tension (Pa,CO2) on admission with 26
patients admitted to ICU and treated with CMV (controls). The primary end points
of the study were inhospital death for both groups and the need for endotracheal
intubation for cases. The secondary endpoints were length and complications of
mechanical ventilation and length of hospital stay. The effectiveness of matching
was 91%. Mortality rate was 23% for cases and 27% for controls (NS), five cases
needed endotracheal intubation, four of whom subsequently died. The duration of
ventilation in survivors was significantly lower in cases than in controls, with
a median of 16 h (range 2-111) versus 96 h (range 12-336) (P<0.02), whereas the
length of hospital stay was similar in the two groups, with a median of 12 days
(range 2-47) for cases vs 12 days (range 3-43) (NS) for controls. No
complications were observed in cases, whereas three controls developed infective
complications. These results suggest that negative pressure ventilation is as
efficacious as conventional mechanical ventilation for the treatment of acute
respiratory failure in patients with chronic obstructive pulmonary disease and
that it is associated with a shorter duration of ventilation and a similar length
of hospital stay compared with conventional mechanical ventilation.
PMID- 9762774
TI - Measurement of overinflation by multiple linear regression analysis in patients
with acute lung injury.
AB - Strategies to optimize alveolar recruitment and prevent lung overinflation are
central to ventilatory management of patients with acute lung injury (ALI). The
recent description of overinflation using multilinear regression analysis of
airway pressure (Paw) and flow (V') data allows a functional assessment of lung
mechanics. However, this technique has not been studied in ALI patients. During
15 positive end-expiratory pressure (PEEP) trials in 10 ALI patients, respiratory
elastance was partitioned into volume-independent (E1) and volume-dependent
(E2VT) components, where Paw=(E1+E2VT)V+RrsV'+Po; where V is volume, VT is tidal
volume, Rrs is respiratory resistance and Po is static recoil pressure at end
expiration (equivalent to total PEEP). Then, %E2 was calculated as
(100E2VT)/(E1+E2VT); a measure of lung overinflation when %E2>30%. Alveolar
recruitment, assessed as a PEEP-induced increase in V>50 mL at a constant Paw
occurred in 14 of 15 trials (299+/-34 mL, mean+/-SEM), but was independent of the
degree of lung inflation. Lung overinflation was common (six of 15 clinically set
PEEP levels) and occurred despite a dynamic elastic distending pressure (Pel,dyn)
<30 cmH2O during 18 of 36 PEEP titrations. During a PEEP titration the resultant
%E2 was directly related to delta(peak airway pressure-Po) (rs=0.86, p<0.001) and
delta(Pel,dyn-Po) (rs=0.89, p<0.001). The 95% predictive intervals for a 2 cmH2O
change in either driving pressure were %E2 values of 30.4-68.1% and 32.8-69.2%,
respectively. Single or continuous measurement of %E2 (a measure of lung
inflation) is a readily available method for titrating ventilatory parameters.
Further, during a positive end-expiratory pressure titration a change in
ventilatory driving pressure > or =2 cmH2O is indicative of overinflation.
PMID- 9762775
TI - Efficacy of Curosurf in a rat model of acute respiratory distress syndrome.
AB - Curosurf, a natural lung surfactant, is considered a potential candidate for
improving the treatment of acute respiratory distress syndrome (ARDS). To
investigate this in a rat model of early-stage ARDS, Curosurf (62.5, 125 or 250
mg x kg(-1)) was administered by intratracheal bolus at 10 or 24 h following an
intratracheal lipopolysaccharide (LPS; 1.6 mg x kg(-1)) challenge. Survival,
respiratory frequency (fR), lung wet weight (LWW), total protein and cell
differentiation in bronchoalveolar lavage fluid (BALF) were assessed. Curosurf
treatment at 10 h after LPS challenge resulted in 100% survival at both 62.5 and
125 mg x kg(-1); at a dose of 250 mg x kg(-1) administered at 10 h after LPS, 1
out of 6 animals died. At a dose of 125 mg x kg(-1) Curosurf administered at 24 h
after LPS, 1 out of 6 animals died. In contrast, only 35% of animals survived
when not treated with Curosurf. Curosurf treatment resulted in an improved fR and
in a significantly decreased LWW, total protein and number of polymorphonuclear
cells in BALF. In conclusion, Curosurf treatment improved respiratory frequency
and decreased mortality, pulmonary oedema and inflammation. As the decreased
mortality was observed in spontaneously breathing nonoxygenated animals, the
results cannot be extrapolated to human artificially ventilated acute respiratory
distress syndrome patients with the expectation of a decreased mortality. The
results suggest, however, that Curosurf may be an important therapeutic measure
in early-stage acute respiratory distress syndrome.
PMID- 9762776
TI - Elevation of specific immunoglobulin A antibodies to both allergen and bacterial
antigen in induced sputum from asthmatics.
AB - The antigenic specificity and pathogenetic significance of immunoglobulins in
airway secretion from asthmatic patients have not been established. Elevated
levels of B-cells and immunoglobulin (Ig)A antibodies have been reported in
sputum of asthmatics and these levels correlated with the eosinophil counts and
levels of degranulated cytotoxic proteins from eosinophils. This study aimed to
investigate the antigen specificity and possible pathogenetic significance of
antibodies in airway secretion from asthmatic patients. Specific IgA and IgG
antibodies to both allergen (Dermatophagoides farinae) and bacterial antigen
(capsular polysaccharide antigen from Streptococcus pneumoniae) were measured in
sputum from 16 atopic asthmatic patients sensitized to D. farinae and 12
nonatopic, nonasthmatic controls by enzyme-linked immunosorbent assay. Sputum was
induced by inhalation of hypertonic saline. Eosinophil cationic protein (ECP)
levels in sputum from asthmatic patients were measured by the Pharmacia CAP
system. Levels of IgA to both D. farinae and S. pneumoniae and IgG to D. farinae
in the sputum from asthmatic patients were significantly higher than those from
controls (p<0.005). No significant difference was found in the levels of IgG to
S. pneumoniae between the two groups. In asthmatic patients, there were
significant correlations between IgA to D. farinae and S. pneumoniae (r=0.76,
p=0.003). Sputum ECP levels correlated significantly with IgA to D. farinae
(r=0.55, p=0.03) and S. pneumoniae (r=0.56, p=0.03) and IgG to D. farinae
(r=0.52, p=0.04), but not with IgG to S. pneumoniae in asthmatic patients. In
conclusion, specific immunoglobulin A antibodies to both allergen and bacterial
antigen were elevated in induced sputum from atopic asthmatics and their possible
involvement in eosinophil degranulation was suggested.
PMID- 9762777
TI - Increased peak expiratory flow variation in asthma: severe persistent increase
but not nocturnal worsening of airway inflammation.
AB - Asthma at night is characterized by a nocturnal increase in airway obstruction.
It has been hypothesized that nocturnal asthma results from an increase in airway
wall inflammation at night. However, studies on inflammatory cells in
bronchoalveolar lavage (BAL) fluid and bronchial biopsies have produced
conflicting data. This study assessed inflammatory cell numbers at 16:00 h and
04:00 h in bronchial biopsies of 13 healthy controls, 15 asthmatic patients with
peak expiratory flow (PEF) variation < or =15% and 10 asthmatic patients with PEF
variation >15%. There was no significant increase at night in the number of CD3,
CD4, CD8, CD25, AAI (tryptase) and EG2-immunopositive cells in the submucosa in
both groups. Numbers of EG2-positive cells in the two asthmatic groups were
significantly higher than in healthy controls, both at 16:00 h (p<0.05) and 04:00
h (p<0.01). The number of EG2, CD4 and CD25-positive cells at 04:00 and 16:00 h
tended to be higher in asthmatics with a PEF variation >15% than in asthmatics
with PEF variation < or =15%. At 04:00 h the median numbers of EG2-positive cells
(per mm basement membrane) in subjects with PEF variation >15% and < or =15% were
6 and 3 cells, respectively, and at 16:00 h 4 and 25 cells respectively.
Increased nocturnal airway obstruction is not associated with increased numbers
of inflammatory cells in the bronchial submucosa at night. Apparently, asthmatic
patients with a peak expiratory flow variation >15% suffer from a higher overall
severity of bronchial inflammation at night and during the day.
PMID- 9762778
TI - Sputum eosinophilia is more closely associated with airway responsiveness to
bradykinin than methacholine in asthma.
AB - Hyperresponsiveness of the airways to various spasmogenic stimuli is a
characteristic feature of bronchial asthma. However, the association between the
different stimuli to which asthmatic airways are hyperresponsive and airways
inflammation is not completely understood. We have investigated the relationship
between airway inflammation and airway hyperresponsiveness in asthma, as assessed
by bronchoprovocation tests to methacholine and bradykinin, two well defined
bronchoconstrictor agonists. Sputum induction by hypertonic saline and
methacholine and bradykinin challenges were performed in 14 nonsmoking subjects
with mild-to-moderate asthma. Airway responsiveness to either agonist did not
correlate with sputum neutrophils, lymphocytes, and macrophages. Whilst the
absolute number of eosinophilia failed to be significantly related to
methacholine responsiveness (r=-0.47; p=0.09), it correlated markedly and
significantly with provocative concentration of methacholine causing a 20% fall
in forced expiratory volume in one second (r=0.72; p<0.01). When expressed as %
of total cell counts, sputum eosinophils correlated with both types of
responsiveness (r=-056; p=0.04 and r=-0.76, p<0.001, respectively). Although the
concentration of eosinophil cationic protein (ECP) in the sputum correlated with
the absolute numbers of eosinophils (r=0.62; p<0.02), no correlation was found
between ECP levels and the airway responsiveness to any of the agonists tested.
In subjects with mild-to-moderate asthma, airway responsiveness to bradykinin is
more strongly associated with the magnitude of eosinophilic inflammation in the
airways than methacholine. This finding underlines the selectivity of diverse
agonists in assessing airway hyperresponsiveness and cellular inflammation in
asthma.
PMID- 9762780
TI - Characteristics of asthma in the elderly.
AB - Asthma occurs more frequently in the elderly than is usually appreciated and may,
therefore, be underdiagnosed and undertreated. This study evaluated the
relationship between asthma symptoms and the degree of airflow obstruction in
elderly and young asthmatics. Fifteen young asthmatics (<65 yrs) (group A), 15
aged >65 yrs with onset of symptoms before 65 yrs (group B), and 15 aged >65 yrs
with onset of symptoms after 65 yrs (group C), were studied. Patients used daily
diary cards, during 2 weeks, to record inhaled beta2-agonist consumption and
severity of asthma symptoms. Long-standing asthma was associated with a
significantly lower forced expiratory volume in one second as compared with
recent onset asthma. The asthma-symptom score was highest in group A, lower in
group B and significantly lower in group C. When symptoms were related to the
degree of obstruction (asthma index), it was higher in the young asthmatics than
in both groups of elderly patients. In conclusion, elderly patients with long
standing asthma had more severe airway obstruction than patients with recently
acquired disease. Older patients particularly those with long-standing disease
complained less about asthma symptoms. Within the various groups of patients,
subjective symptoms of asthma were negatively related to asthma duration.
PMID- 9762779
TI - Individual use of antiasthmatic drugs in the European Community Respiratory
Health Survey.
AB - A previous analysis of drug utilization in the European Community Respiratory
Health Survey found that only between 8 and 29% of subjects with asthma-related
symptoms were using antiasthmatic medication in the different areas studied. The
aim of this analysis was to investigate which variables were related to
individual use of antiasthmatic medication in different geographical areas.
Thirty-three centres in 14 countries were analysed, in which a total of 16,854
people (52.1% females, mean age 33.8 yrs, range 20-48) underwent a structured
interview, measurement of specific immunoglobin E, spirometry and methacholine
challenge test. The use of antiasthmatic drugs in individuals was, in most
countries, independently related to asthma-related respiratory symptoms,
bronchial hyperresponsiveness (BHR) and atopy. In all countries smokers with
respiratory symptoms were less likely to be using antiasthmatic drugs than
nonsmokers and exsmokers. In four of 14 countries females were significantly more
likely to use antiasthmatic medication than males, while age and socioeconomic
status were unrelated to medication. The use of inhaled anti-inflammatory drugs
was positively related to symptoms, BHR and atopy and negatively related to
current smoking. In conclusion, in many countries smokers were less likely to be
using antiasthmatic drugs than were nonsmokers with comparable levels of symptoms
and bronchial hyperresponsiveness. Age and socioeconomic status were unrelated to
medication, while in some countries females were more likely than males to use
antiasthmatic medication.
PMID- 9762781
TI - Protective effect of respiratory devices in farmers with occupational asthma.
AB - To the authors' knowledge there have been no previous reports on the protection
afforded by powered filtering respirators in farmers with occupational asthma
attributed to the inhalation of organic dust. In order to investigate this
question, 26 farmers with occupational asthma were challenged with an exposure to
work-related dusts for up to 60 min. This resulted in highly significant
increases in airway resistance (Raw), thoracic gas volume (TGV) and specific
airway resistance (sRaw) compared to baseline values. After a mean period of 21
weeks the farmers were subjected to a second challenge, this time wearing a
protective respiratory device (RD) with a P2 filter. Significant increases in
Raw, TGV and sRaw were again observed, but on average these were 50-80% smaller
than the increases seen when RDs were not worn. These differences were found to
be statistically significant. This shows that the use of a respiratory device in
farmers suffering from occupational asthma reduces the development of bronchial
obstruction but does not prevent it. The use of this kind of respiratory device
cannot substitute for the proper management of asthma since the devices do not
offer complete protection.
PMID- 9762782
TI - Tolerability to high doses of formoterol and terbutaline via Turbuhaler for 3
days in stable asthmatic patients.
AB - This randomized, double-blind, crossover study in two parts compared tolerability
to high doses of formoterol (Oxis Turbuhaler) with that of high doses of
terbutaline (Bricanyl Turbuhaler). After Holter monitoring at home, 12 patients
were treated with 4+4+4 doses of formoterol Turbuhaler, 6 microg x dose(-1),
(total daily metered dose 72 microg) or 4+4+4 doses of terbutaline Turbuhaler,
0.5 mg x dose(-1) (daily dose 6 mg) given in the morning, after lunch and in the
evening, for 3 consecutive days. After a one week washout period at home,
patients received the alternative treatment. Thereafter, 15 other patients
received 8+6+6 doses of formoterol Turbuhaler (total daily metered dose 120
microg) or 8+6+6 doses of terbutaline Turbuhaler (daily dose 10 mg). Pulse,
cardiac frequency, blood pressure, serum potassium, electrocardiogram and forced
expiratory volume in one second (FEV1) were registered at regular intervals and
Holter monitoring was applied during all 4 treatment days. Terbutaline 6 mg
showed significantly greater systemic effects than formoterol 72 microg on pulse,
blood pressure, cardiac frequency and QTc (QT interval corrected for heart rate).
Terbutaline 10 mg had significantly greater effects than formoterol 120 microg on
serum potassium levels, pulse, cardiac frequency and QTc. No differences in FEV1
levels were found. Both drugs were safe and generally well tolerated on both dose
levels. In conclusion, high doses of formoterol Turbuhaler over 3 days were
generally safe and well tolerated. Daily doses of 6 mg and 10 mg terbutaline
Turbuhaler were systemically more potent than 72 microg and 120 microg
formoterol, respectively. The safety margin thus appears to be wide if patients
happen to use extra doses of formoterol in addition to those prescribed for
regular use.
PMID- 9762783
TI - Subsensitivity to bronchoprotection against adenosine monophosphate challenge
following regular once-daily formoterol.
AB - Regular treatment with inhaled long-acting beta2-agonists leads to subsensitivity
to their bronchoprotective effects, although the effect of dosing frequency on
this subsensitivity is not known. The aim of this study was to assess whether a
once-daily dosing regimen with formoterol might be associated with a lesser
degree of subsensitivity. In a randomized placebo-controlled double-blind, double
dummy crossover study 10 asthmatics treated with inhaled steroids (mean age 31
yrs, forced expiratory volume in one second (FEV1) 82% predicted) received 1 week
of treatment with: formoterol dry powder 24 microg twice daily (08:00 and 20:00
h); formoterol 24 microg once daily (20:00 h); or identical placebo. Adenosine
monophosphate (AMP) bronchial challenge was performed 12 h after the first and
the last dose of each treatment. There was significant loss of protection with
formoterol twice daily between the first and last dose (geometric mean
provocative concentration causing a 20% fall in FEV1 (PC20)): 475 versus 129 mg x
mL(-1) (a 3.7-fold loss, p=0.006) and with formoterol once daily: 367 versus 127
mg x mL(-1) (a 2.9-fold loss, p=0.005), compared with placebo: 71 versus 75 mg x
ml(-1) (nonsignificant). There was no significant difference in the degree of
loss of protection between formoterol once and twice daily. For first-dose
protection there was a significant difference between active treatments and
placebo, but after the last dose the residual protection between active
treatments and placebo was not significant. Thus, in patients taking inhaled
corticosteroids, regular formoterol 24 micreog once daily induces a similar
degree of subsensitivity to adenosine monophosphate bronchial challenge as with
formoterol 24 microg twice daily. This in turn suggests that even with a 24-h
dosing interval there is the development of tolerance to formoterol by prolonged
occupancy of airway beta2-adrenoceptors.
PMID- 9762784
TI - Effect of theophylline on CD11b and L-selectin expression and density of
eosinophils and neutrophils in vitro.
AB - The nonspecific phosphodiesterase inhibitor theophylline, widely used in asthma
therapy, may cause a decrease in inflammatory responses of airways. In asthma,
eosinophils migrate to the airway wall and become activated. Activated
eosinophils are characterized by low cell density, as well as increased
expression of CD11b and reduced expression of L-selectin, two adhesion molecules
involved in transendothelial migration. To study the anti-inflammatory effect of
theophylline on granulocyte adhesion molecules in vitro, the platelet-activating
factor (PAF)-induced density shift was determined by density centrifugation and
the modulation of CD11b and L-selectin expression by flow cytometry on
eosinophils and neutrophils in human whole blood. A relatively high concentration
of theophylline (10(-3) M) inhibited the increase in the percentage of hypodense
eosinophils and neutrophils in whole-blood samples after PAF stimulation in
vitro. A more pharmacological concentration (10(-4) M) inhibited the CD11b
upregulation and L-selectin shedding induced by PAF (10(-7) M) on both
eosinophils and neutrophils. The effect of isoproterenol on the inhibitory effect
of theophylline was mainly additive, but a small synergistic effect could not be
excluded. In conclusion theophylline can attenuate eosinophil and neutrophil
activation in vitro at the level of adhesion molecule expression and changes in
cell density. This may have implications for transendothelial migration of these
cells in asthma.
PMID- 9762785
TI - Four years' experience of intravenous colomycin in an adult cystic fibrosis unit.
AB - Nearly all strains of Pseudomonas aeruginosa are sensitive to colomycin
sulphomethate, but studies in the 1970s using large doses demonstrated
significant renal and neurotoxic side-effects and it is not now commonly used. In
this study colomycin (2 megaunits i.v. t.d.s.) has been used extensively in adult
cystic fibrosis (CF) patients and its use reviewed to determine its efficacy and
safety profile. Fifty-two CF patients (28 male, 24 female; mean age 26 yrs, range
17-39 yrs) received 135 courses (mean two courses each, range 1-7, median length
14 days) of i.v. colomycin (2,414 patient days in total). It was used in
combination with one other i.v. antibiotic in 114 courses (85%) and with two
others in 18 (13%). In all cases there was significant improvement in spirometry
(pretreatment forced expiratory volume in one second (FEV1) % predicted mean
44.4, range 10-101; post-treatment mean 51.3, range 14-108; p<0.0001). No patient
had any neurotoxicity but one developed a skin rash and myositis. There was no
change in renal function (urea mean pretreatment 4.1 mmol x L(-1) (sD 1.4), mean
post-treatment 43 (2.2), p=NS; creatinine mean pretreatment 77.9 mmol x L(-1)
(15.3), mean post-treatment 803 (21.6), p=NS). In the authors' experience
intravenous colomycin sulphomethate in moderate doses is an effective and safe
antipseudomonal antibiotic which is easy to administer. Other clinicians should
consider its use in patients with cystic fibrosis.
PMID- 9762786
TI - Leukocyte counts and macrophage phenotypes in induced sputum and bronchoalveolar
lavage fluid from normal subjects.
AB - It is unclear whether leukocytes in induced sputum (IS) and bronchoalveolar
lavage (BAL) represent the same cell populations. To compare leukocyte counts and
macrophage phenotypes and investigate any measurable dithiothreitol (DTT)
mediated effect on macrophage immunocytochemical staining results, IS and BAL
samples from nine healthy smokers and seven nonsmokers were examined. BAL and IS
samples were processed and cell viability and cell counts were assessed. The
macrophages were characterized by seven monoclonal antibodies (RFD1, RFD7, CD11b,
CD54, CD68, CD71 and HLA-DR) using an indirect immunoalkaline phosphatase method.
Intraindividual comparison of IS and BAL showed that IS samples from smokers and
nonsmokers contained a lower total cell count (p<0.01 smokers, p<0.05
nonsmokers), a lower percentage of macrophages (both p<0.05) and a higher
percentage of neutrophils (both p<0.05) than BAL samples. In addition, nonsmokers
sputum samples contained a lower proportion of lymphocytes (p<0.05) than BAL. The
macrophage expression of RFD7 and CD71 was higher in smokers sputum samples (both
p<0.05) than in BAL, while nonsmokers sputum macrophages showed a higher
expression of CD54 and CD71 (both p<0.05) than BAL macrophages. DTT-incubated BAL
samples showed no difference in macrophage antigen expression from BAL samples
not exposed to DTT. In conclusion, the relative proportions of leukocytes and the
macrophage phenotypes differed between induced sputum and bronchoalveolar lavage
suggesting that the methods provide samples from different lung compartments,
inhabited by cells with different phenotypes.
PMID- 9762787
TI - Expression of leukocyte integrins and tissue factor in mononuclear phagocytes.
AB - Coagulation is intimately involved in the pathology of inflammation. The
leukocyte beta2-integrins have several functions, including serving as receptors
for coagulation factor X and fibrinogen. Tissue factor (TF) is a receptor for
factor VII and a very potent trigger of coagulation. The intention of this study
was to examine a possible coexpression of beta2-integrins (CD11b/CD18 and
CD11c/CD18) and the procoagulant TF in alveolar macrophages (AM) and blood
monocytes, i.e. cells of the same differentiation lineage. The expression of
beta2-integrins in human AM isolated by bronchoalveolar lavage and in blood
monocytes was analysed by flow cytometry, whereas TF activity was analysed in a
one-stage clotting assay. In monocytes, TF activity, CD11b and CD11c expression
were highly inducible by lipopolysaccharide (LPS), with a 13-, 19- and four-fold
increase, respectively. In AM, TF and beta2-integrins were all constitutively
expressed, but the expression could not be further enhanced by LPS stimulation.
CD11b and CD11c expression varied inversely with the cell size of AM, in contrast
to TF activity which is known to be proportional to AM cell size. In vitro
expression of beta2-integrins and tissue factor in lipopolysaccharide-stimulated
blood monocytes seems to be intimately coregulated, whereas the expression of
these receptors in alveolar macrophages seems to be unresponsive to
lipopolysaccharide. These results indicate that blood monocytes and alveolar
macrophages have different roles and use different mechanisms in cell-induced
fibrin formation.
PMID- 9762788
TI - Effects of alkaline protease or restrictocin deficient mutants of Aspergillus
fumigatus on human polymorphonuclear leukocytes.
AB - Several substances including proteases and restrictocin have been suggested as
candidates for virulence determinants in invasive pulmonary aspergillosis.
However, the roles of such substances are not well understood. This study
compared the in vitro suppressive effects of Aspergillus fumigatus culture
filtrates (ACFs), on the functions of human polymorphonuclear leukocytes (PMNLs),
the principal cells in the host defence against aspergillus hyphae, from a
clinically isolated wild-type and isogenic mutant strains which lack production
of elastolytic alkaline protease (Alp) and/or restrictocin. ACFs were obtained by
culturing conidia of each strain in Medium- 199 at 37 degrees C for 5 days. ACFs
of the wild-type significantly (p<0.01) suppressed chemotaxis, superoxide anion
(O2-) release and PMNL-mediated hyphal damage, compared with the control (Medium
199). ACFs of the mutant strains that lack Alp or restrictocin significantly
(p<0.01) suppressed chemotaxis and O2(-)-release, but did not suppress hyphal
damage, compared with the control. The wild-type significantly (p<0.01)
suppressed chemotaxis of PMNLs compared with the mutant strains lacking Alp or
restrictocin, whereas there were no significant differences in suppression of O2(
)-release and hyphal damage by PMNLs. ACF of a mutant strain that lacks both Alp
and restrictocin had much less activity, but significantly (p<0.01) suppressed
chemotaxis of PMNLs compared with the control. In conclusion, alkaline protease
and restrictocin may play roles in the suppressive effect of Aspergillus
fumigatus culture filtrates on the functions of human polymorphonuclear
leukocytes. Other antiphagocytic substances produced by Aspergillus fumigatus
remain to be identified.
PMID- 9762789
TI - Neutrophils induce damage to respiratory epithelial cells infected with
respiratory syncytial virus.
AB - The mechanisms by which respiratory syncytial virus (RSV) infection induces
bronchiolitis and airway disease are unclear. The presence of large numbers of
polymorphonuclear leukocytes (PMN) in the airways of infants with RSV infection
suggests a potential role of PMN in airway injury associated with RSV infection.
To investigate the potential role of neutrophils in RSV bronchiolitis, human
alveolar type II cells (A549 cells) were infected with different doses of RSV for
6-48 h. A 51Cr-releasing assay was used to measure PMN-induced damage and image
analysis was used to determine PMN adhesion and detachment of epithelial cells.
The results showed that RSV infection of epithelial cells enhanced PMN adherence
in a dose- and time-dependent pattern, RSV infection alone could damage and
detach epithelial cells to a limited extent and PMN significantly augmented RSV
infection-induced damage and detachment of epithelial cells. These data suggest
that respiratory syncytial virus infection of respiratory epithelial cells
enhances neutrophil adhesion to the epithelium and that activated neutrophils
augment the damage and detachment of epithelium infected with the virus.
Polymorphonuclear leukocytes may contribute to the pathogenesis of respiratory
syncytial virus airway disease by inducing epithelial damage and cell loss.
PMID- 9762790
TI - Th2 cytokines exert a dominant influence on epithelial cell expression of the
major group human rhinovirus receptor, ICAM-1.
AB - Intercellular adhesion molecule (ICAM)-1 is a cell receptor important in both
human rhinovirus (HRV) attachment and immune effector cell mobilization. The
level of expression of ICAM-1 by epithelial cells (EC) therefore plays a crucial
role in the intricate biological phenomena underlying viral binding, host
infection and consequent inflammatory events. As T-helper (Th)2 lymphocytes
predominate within the asthmatic airway, the influence was evaluated of Th2
associated mediators in the modulation of ICAM-1 expression on uninfected and HRV
infected EC. H292 EC were cultured in vitro, with varying concentrations of
interleukin (IL)-4, IL-5, IL-10 and IL-13 for 24 h and then infected with live
HRV-14. Surface ICAM-1 expression was assessed by immunocytochemistry. Infection
with HRV-14 resulted in a twofold increase in ICAM-1 expression. IL-4, IL-5, IL
10 and IL-13 produced a 2.7-5.1-fold enhancement of ICAM-1 expression of
uninfected cells and caused approximately a further twofold increase in infected
cells over the expression induced by HRV infection itself. Interferon-gamma in
combination with each Th2-associated cytokine only slightly reduced, but did not
override, the Th2-induced level of ICAM-1 expression on both uninfected and virus
infected EC. These data suggest that the effects of Th2-associated cytokines on
intercellular adhesion molecule-1 expression and recovery of infectious virus are
dominant over the effects of the Th1-associated cytokines such as interferon
gamma. Since the airway mucosa in atopic asthma is predominantly infiltrated by
Th2 lymphocytes, these results could explain both the increased susceptibility to
human rhinovirus infection in asthmatic patients and the associated exacerbation
of asthma symptoms.
PMID- 9762791
TI - Tracking of lung function parameters and the longitudinal relationship with
lifestyle.
AB - The purpose of this study was to analyse tracking (i.e. relative stability over
time/predictability of future values by early measurements) of lung function
parameters and their longitudinal relationship with lifestyle (smoking, alcohol
consumption, daily physical activity, neuromotor and cardiopulmonary fitness, and
dietary intake of retinol and polyunsaturated fatty acids (PUFA)). Data were
obtained from the observational Amsterdam Growth and Health Study, a longitudinal
study with six repeated measurements between ages 13-27 yrs (n=167). The
statistical analyses were carried out with generalized estimating equations. The
following "stability" coefficients were found: for forced vital capacity (FVC) in
males 0.66 (95% confidence interval (CI): 0.54-0.77) and in females 0.51 (95% CI:
0.43-0.60); for forced expiratory volume in one second (FEV1) in males 0.65 (95%
CI: 0.50-0.80), in females 0.53 (95% CI 0.46-0.60); for peak expiratory flow
(PEF) in both males and females 0.41 (95% CI: 0.31-0.51). Positive relationships
were found between alcohol consumption and FVC and FEV1 and between neuromotor
fitness and PEF and (only for males) with FVC and FEV1. Physical activity was
inversely related to PEF and the intake of PUFA positively related to FVC and
FEV1. Smoking was related to a decrease in FVC and FEV1; changes in physical
activity positively correlated to changes in FVC. In conclusion, high to moderate
stability/tracking was observed for forced vital capacity and forced expiratory
volume in one second; for peak expiratory flow it was slightly lower. Preventive
strategies regarding improvements of lung function should focus on smoking
cessation and improving daily physical activity.
PMID- 9762792
TI - Impaired ventilatory function and elevated insulin levels in nondiabetic males:
the Normative Aging Study.
AB - Lower levels of baseline ventilatory function have consistently been associated
with increased risk of cardiovascular mortality in prospective studies, but the
underlying mechanisms are not known. Increased risk of coronary heart disease is
associated with higher serum insulin levels. This report examines the
relationship between ventilatory function and indirect measures of insulin
resistance. Cross-sectional data from 922 nondiabetic participants in the
Normative Aging Study were analysed using multiple linear regression models with
adjustment for potential confounders. Forced vital capacity (FVC) and forced
expiratory volume in one second (FEV1) were examined in relation to indicators of
insulin resistance, i.e. fasting insulin and the fasting insulin resistance index
(FIRI). Diabetics were excluded because impaired insulin secretion interferes
with the validity of these as measures of insulin resistance. Fasting insulin and
FIRI were negatively correlated with FVC and FEV1 (all p< 0.001). These
associations persisted after adjusting for potential confounders including age,
height, body mass index, waist to hip circumference ratio, physical activity,
alcohol intake and smoking in separate multiple linear regression models, for
both insulin (all p< or =0.0008) and FIRI (all p< or =0.0001). Negative cross
sectional associations between ventilatory function and indirect measures of
insulin resistance were found in nondiabetic males. Insulin resistance may
contribute to the previously unexplained association between ventilatory function
impairment and cardiovascular mortality. Mechanisms underlying the relationship
between insulin resistance and decreased ventilatory function remain to be
elucidated.
PMID- 9762793
TI - Baseline ventilatory function predicts the development of higher levels of
fasting insulin and fasting insulin resistance index: the Normative Aging Study.
AB - A consistent but as yet unexplained association between baseline ventilatory
function and risk of coronary heart disease (CHD) has been reported from many
prospective studies. Insulin-resistant states are associated with increased risk
of CHD. Forced vital capacity (FVC), forced expiratory volume in one second
(FEV1) and maximal mid-expiratory flow rate (MMEF) at study entry were examined
as predictors for indirect measures of insulin resistance after a mean follow-up
interval of 20.9 yrs in 1050 nondiabetic male subjects in the Normative Aging
Study. Males in the top quintile of insulin or fasting insulin resistance index
(FIRI) levels at follow-up were defined as being relatively insulin resistant.
FVC was negatively associated with risk of being relatively insulin resistant
using the insulin (p=0.002) or FIRI (p=0.0001) criteria at follow-up in logistic
regression models adjusting for baseline age, body mass index, fat distribution
pattern and cigarette smoking. Similar associations were found for FEV1 and MMEF.
Additional adjustment for baseline postcarbohydrate challenge glucose levels made
little difference to the results, suggesting that baseline glucose intolerance
was not a significant source of bias. These findings are consistent with the
possibility that insulin resistance may be one of the factors mediating the
previously unexplained prospective association between impairment of ventilatory
function and risk of mortality from coronary heart disease.
PMID- 9762794
TI - Time to peak tidal expiratory flow and the neuromuscular control of expiration.
AB - The ratio of the time needed to reach peak tidal expiratory flow (tPTEF) and the
duration of expiration (tE) is used to detect airflow obstruction in young
children. tPTEF is decreased in patients with asthma, but knowledge about the
physiological determinants of this parameter is scarce. This study examined the
relationship between tPTEF and postinspiratory activities of inspiratory muscles
and evaluated the effects of changing sensory information from the lung. Airflow
patterns and electromyographic (EMG) activity of inspiratory muscles were
recorded in seven spontaneously breathing, anaesthetized cats. The trachea was
cannulated and, as a result, the larynx and upper airways were bypassed. Changes
in postinspiratory muscle activity were induced by changing afferent sensory
nerve information (by cooling the vagus nerves, by administration of histamine
and by additional application of continuous positive airway pressure (CPAP)).
Durations of postinspiratory activities of the diaphragm and intercostal muscles
(characterized by their time constants tau diaphr and tau interc) correlated
strongly with tPTEF (r=0.85 and 0.77, respectively). Tau diaphr, tau interc and
tPTEF were significantly increased during cooling of the vagus nerves (4-8
degrees C) compared with values at 22 and 37 degrees C (p<0.05). Conversely,
administration of histamine and CPAP caused significant decreases in tau diaphr,
tau interc and tPTEF, which were absent during cooling of the vagus nerves. In
conclusion, the time needed to reach peak tidal expiratory flow is highly
influenced by the activities of inspiratory muscles during the early phase of
expiration which, in turn, depend on the activities of vagal receptors in the
lung.
PMID- 9762795
TI - Acute effects of hypoxaemia, hyperoxaemia and hypercapnia on renal blood flow in
normal and renal transplant subjects.
AB - The aim of this investigation was to study noninvasively the effects of
hypoxaemia, hyperoxaemia and hypercapnia on renal blood flow in normal subjects
and renal allograft recipients, i.e. with denervated kidneys. By comparing these
two groups, the influence of renal innervation on any resulting changes in renal
blood flow could be ascertained. Nine normal and eight renal allograft recipients
were studied. Each subject inhaled the following gas mixtures in order: room air,
10% O2 (hypoxaemia), 10% O2 + baseline CO2 (isocapnic hypoxaemia), 10% O2 + high
CO2 (hypercapnic hypoxaemia), 100% O2 (hyperoxaemia), 100% O2 + baseline CO2
(isocapnic hyperoxaemia) and 100% O2 + high CO2 (hypercapnia hyperoxaemia). Using
Doppler ultrasonography, the pulsatility index (PI), an index of renovascular
resistance, was measured at the various gas inhalation levels. In normal
subjects, the renovascular resistance increased in response to hypoxaemia, with a
greater increase in response to hypercapnic hypoxaemia. Hyperoxaemia caused a
decrease in renovascular resistance but this was abolished with the addition of
CO2. There was a similar pattern in the PI response to the different gas
inhalations in the renal transplant subjects, but these responses were attenuated
in comparison with those of the normals. In conclusion, renal denervation does
not completely abolish the renovascular responses to inhaled oxygen and carbon
dioxide.
PMID- 9762796
TI - In vivo hypoxic exposure impairs metabolic adaptations to a 48 hour fast in rats.
AB - Hypoxia is well known to affect carbohydrate metabolism through its action on
liver function and thus on glucose homeostasis. The aim of this study was to
examine the carbohydrate, lipid and protein metabolic responses to 48 h of
hypoxia, as well as the hormonal adaptations using both normoxic controls and
hypoxic animals in the fasted state to standardize for the marked hypophagia
observed in response to hypoxia. Hypoxia exposure (inspiratory oxygen fraction
(FI,O2) = 0.1) resulted in a greater weight loss (-23 +/- 3.6% versus -16 +/- 2%
in controls, p<0.001). Hypoxia plus fasting led to a significant increase in
plasma glucose, lactate, insulin and catecholamine concentrations, while the
increase in free fatty acid and beta-hydroxybutyrate was abolished. Changes in
plasma amino acid patterns were not affected by hypoxia. Liver glycogen depletion
was significantly less pronounced in the hypoxic group, while phosphoenolpyruvate
carboxykinase (a key enzyme of liver gluconeogenesis) activity and transcription
enhancements were abolished by hypoxia. Overall, hypoxic exposure in rats fasted
for 48 h resulted in a unique pattern that differed from responses to injury or
fasting per se. Oxygen seems to play a central role in the metabolic adaptation
to fasting, from gene expression to weight loss. Since hypoxaemia associated with
fasting has detrimental effects on nutritional balance, the present observations
may be clinically relevant in the setting of acute exacerbation with hypoxaemia
for chronic respiratory disease.
PMID- 9762797
TI - Mouth occlusion pressure, CO2 response and hypercapnia in severe chronic
obstructive pulmonary disease.
AB - The resting mouth occlusion pressure 0.1 s after onset of inspiration (P0.1) and
minute ventilation (V'E) and their response to CO2 in patients with chronic
obstructive pulmonary disease (COPD) remain controversial. The ventilatory drive
and the factors that predict resting arterial CO2 tension (Pa,CO2) were studied
in 19 eucapnic and 14 hypercapnic severe COPD patients, and 20 controls. The CO2
response was evaluated by the Read technique. The V'E, and P0.1 as a function of
end-tidal CO2 tension (Pet,CO2) was used to study the ventilatory
(deltaV'E/deltaPet,CO2) and P0.1 response (deltaP0.1/deltaPet,CO2). In the
patients, respiratory muscle function and pleural occlusion pressure 0.1 s after
onset of inspiration (Ppl,0.1) were evaluated with simultaneous measurement of
pleural (Ppl) and gastric (Pga) pressures. Hypercapnic patients had lower forced
vital capacity (FVC), forced expiratory volume in one second (FEV1), and arterial
O2 tension (Pa,O2). Resting P0.1 was higher in patients than in controls, whereas
deltaP0.1/deltaPet,CO2 was similar in the three groups. There was no difference
in resting P0.1 (3.6+/-2.0 versus 4.3+/-2.8 kPa (2.7+/-1.5 versus 3.2+/-2.1
cmH2O), p=0.2) and Ppl,0.1 (1.4+/-2.3 versus 5.2+/-3.3 kPa (4.08+/-1.7 versus
3.9+/-2.5 cmH2O), p=0.22) between eucapnic and hypercapnic COPD, whereas
deltaV'E/deltaPet,CO2 was lower in the hypercapnic group (0.29+/-0.24 versus
0.66+/-0.5 L x min(-1) x kPa, p<0.001). By logistic regression only FEVI and
increased diaphragmatic load, and not respiratory drive, predicted resting
Pa,CO2. Irrespective of CO2 level, baseline central drive (represented by the
mouth occlusion and pleural pressures) and CO2 response are preserved in most
patients with severe chronic obstructive pulmonary disease. Effective ventilation
is inadequate in the more severely obstructed patients and this results in
hypercapnia. Neuroventilatory coupling failure is an attractive explanation for
chronic hypercapnia in these patients.
PMID- 9762798
TI - Use of mouth pressure twitches induced by cervical magnetic stimulation to assess
voluntary activation of the diaphragm.
AB - There is a need for a simple method to assess the adequacy of diaphragm
activation during voluntary inspiratory efforts in patients with suspected
respiratory muscle weakness. We have compared mouth (Pmo,t), oesophageal (Poes,t)
and transdiaphragmatic (Pdi,t) twitch pressure elicited by cervical magnetic
stimulation (CMS) in five normal men (mean (SD) age 32.2 (1.8) yrs) on two
separate study days. Single magnetic stimuli were delivered at functional
residual capacity during relaxation and during graded voluntary inspiratory
efforts against a closed airway. As voluntary-effort transdiaphragmatic and
oesophageal pressure increased, Pdi,t and Poes,t decreased linearly (r range,
respectively, 0.82-0.98 and 0.87-0.95). During relaxation, Pmo,t was unreliable
due to the poor transmission of intrathoracic pressure, but during inspiratory
efforts, the relation between voluntary mouth pressure and Pmo,t was also linear
(r range 0.84-0.95). On average, our subjects voluntarily generated 99, 100 and
102% of the maximum transdiaphragmatic, oesophageal and mouth pressures predicted
by the respective linear regression equations. Pmo,t was correlated to both
Poes,t and Pdi,t during inspiratory efforts, but not during relaxation. These
studies confirm that twitch pressures induced by CMS during inspiratory efforts
can be assessed at the mouth in normal subjects, providing a simple and non
invasive technique for assessing diaphragm activation during voluntary
inspiratory efforts. Potentially, this technique could be made more sensitive and
accurate and applied to detect submaximal efforts in patients.
PMID- 9762799
TI - Pulmonary haemodynamics in obstructive sleep apnoea: time course and associated
factors.
AB - Changes in pulmonary artery pressure within an obstructive apnoea and elevations
of transmural pulmonary artery pressure (Ppa,tm) towards the end of apnoea are
well known. The purpose of our study was to examine which factors contribute to
the increase of Ppa,tm in an apnoea. In addition, the time course of Ppa,tm and
associated factors during a sleep study was investigated. We analysed the
association of changes in arterial oxygen saturation (Sa,O2), oesophageal
pressure (Poes) to estimate intrathoracic pressure, systolic blood pressure
(BPsys) to estimate left ventricular afterload, apnoea duration and the change in
Ppa,tm (deltaPpa,tm) during the course of obstructive apnoeas. Consecutive
apnoeas in nonrapid eye movement (NREM)-sleep at the beginning, the middle and
the end of the sleep study were analysed in six patients with obstructive sleep
apnoea. The mean systolic Ppa,tm was 28.0+/-12.1 mmHg at the beginning of apnoea
and 38.6+/-15.5 mmHg at the end (deltaPpa,tm 10.5+/-7.4 mmHg; p<0.0001).
DeltaSa,O2 (p<0.0001; odds ratio (OR) 1.45; confidence interval (CI) 1.20-1.76)
and deltaPoes (p<0.0001; OR 1.22; CI 1.11-1.34) were independently associated
with deltaPpa,tm in a multiple regression analysis. Apnoea duration as well as
deltaPoes, deltaPpa,tm and deltaSa,O2 were all significantly higher (p<0.05) in
apnoeas at the middle of the sleep study than at the beginning or the end. In
conclusion, hypoxaemia and mechanical factors as an increase in negative thoracic
pressure contribute to elevations of the transmural pulmonary artery pressure
during an obstructive apnoea. The time course of pulmonary haemodynamics within a
steep study reveals that the highest transmural pulmonary artery pressure occurs
in the middle of the night with no progressive increase towards the end of the
sleep study.
PMID- 9762800
TI - Value of beat-to-beat blood pressure changes, detected by pulse transit time, in
the management of the obstructive sleep apnoea/hypopnoea syndrome.
AB - Two important aspects of a respiratory sleep study are a measure of inspiratory
effort and an estimate of the number of arousals. These can be derived from an
indirect estimate of beat-to-beat blood pressure (BP), pulse transit time (PTT).
This study investigated the reproducibility of inspiratory BP falls (reflecting
inspiratory effort), and BP arousals derived from PTT, and the contribution they
could make to the management of the obstructive sleep apnoea/hypopnoea syndrome
(OSAHS). Overnight PTT was recorded at home in 40 patients being investigated for
OSAHS, and a second PTT recording was made in the sleep laboratory with full
polysomnography. Patients were divided into three groups according to the
severity of their sleep disorder, and a third PTT recording was made at home in
13 patients subsequently established on nasal continuous positive airway pressure
(CPAP). The reproducibility between the home and laboratory studies was
reasonable (r=0.87 for inspiratory BP falls, r=0.81 for BP arousals). Both
derivatives showed a clear progression through the three patient groups, which
returned to normal on treatment. The differences between the groups were
significant (p<0.001 for inspiratory BP falls, p=0.0014 for BP arousals).
Receiver operator characteristic curves, used to compare polysomnography
variables and PTT variables, confirmed that the PTT variables were as good as
apnoea-hypopnoea index (AHI), >4% arterial oxygen saturation dip rate and
electroencephalography micro-arousals at dividing patients into two groups,
either requiring nasal CPAP or not requiring CPAP. Pulse transit time can provide
a noninvasive estimate of inspiratory effort and a measure of arousals that
together document disease severity and response to treatment and may be useful in
managing obstructive sleep apnoea/hypopnoea syndrome.
PMID- 9762801
TI - Maximum rate of change in oesophageal pressure assessed from unoccluded breaths:
an option where mouth occlusion pressure is impractical.
AB - The mouth occlusion pressure 100 ms after onset of inspiration (P0.1) is
considered a clinically useful measure of the combined output of the respiratory
centre and muscle pump. However, theoretical and practical difficulties can arise
when using P0.1 in the assessment of patients with severe chronic obstructive
pulmonary disease (COPD). It was hypothesized that the maximum rate of change in
oesophageal pressure (dPoes,max/dt) may be an alternative to P0.1. To test this
hypothesis P0.1 was compared with mean dPoes,max/dt measured from neighbouring
unoccluded breaths in five normal subjects during CO2 rebreathing. In all
subjects a close correlation was found between both dPoes,max/dt and P0.1 and
carbon dioxide tension (PCO2). In six patients with severe COPD performing
exhaustive treadmill walks, dPoes,max/dt was found to increase progressively with
walking time. Mean dPoes,max/dt at the start was 6.2 cmH2O x 100 ms(-1) and at
the finish was 18.7 cmH2O x 100 ms(-1) (p<0.03). In conclusion, the maximum rate
of change in oesophageal pressure measured from unoccluded breaths could be an
alternative in circumstances where it is not feasible to use measurements of the
mouth occlusion pressure 100 ms after onset of inspiration.
PMID- 9762802
TI - A simple breathing circuit minimizing changes in alveolar ventilation during
hyperpnoea.
AB - Many clinical and research situations require maintenance of isocapnia, which
occurs when alveolar ventilation (V'A) is matched to CO2 production. A simple,
passive circuit that minimizes changes in V'A during hyperpnoea was devised. It
is comprised of a manifold, with two gas inlets, attached to the intake port of a
nonrebreathing circuit or ventilator. The first inlet receives a flow of fresh
gas (CO2=0%) equal to the subject's minute ventilation (V'E). During hyperpnoea,
the balance of V'E is drawn (inlet 2) from a reservoir containing gas, the carbon
dioxide tension (PCO2) approximates that of mixed venous blood and therefore
contributes minimally to V'A. Nine normal subjects breathed through the circuit
for 4 min at 15-31 times resting levels. End-tidal PCO2 (Pet,CO2) at rest, 0, 1.5
and 3.0 min were (mean+/-SE) 5.1+/-0.1 kPa (38.1+/-1.1 mmHg), 4.9+/-0.1 kPa
(36.4+/-1.1 mmHg), 5.0+/-0.2 kPa (37.8+/-1.6 mmHg) and 5.0+/-0.2 kPa (37.6+/-1.4
mmHg) (p=0.53, analysis of variance (ANOVA)), respectively; without the circuit,
Pet,CO2 would be expected to have decreased by at least 2.7 kPa (20 mmHg). Six
anaesthetized, intubated dogs were first ventilated at control levels and then
hyperventilated by stepwise increases in either respiratory frequency (fR) from
10 to 24 min(-1) or tidal volume (VT) from 400 to 1,200 mL. Increases in fR did
not significantly affect arterial CO2 tension (Pa,CO2) (p=0.28, ANOVA). Only the
highest VT decreased Pa,CO2 from control (-0.5 +/- 0.3 kPa (-3.4 +/- 2.3 mmHg),
p<0.05). In conclusion, this circuit effectively minimizes changes in alveolar
ventilation and therefore arterial carbon dioxide tension during hyperpnoea.
PMID- 9762803
TI - Respiratory bronchiolitis in smokers with spontaneous pneumothorax.
AB - Respiratory bronchiolitis (RB) is defined by the accumulation of pigmented
macrophages in the lumen and wall of respiratory and membranous bronchioles of
smokers. The aim of this study was to determine whether spontaneous pneumothorax
was associated with a high prevalence of RB. Seventy-nine consecutive patients
who underwent a surgical procedure (thoracotomy or thoracoscopy) for recurrence
or persistence of primary spontaneous pneumothorax despite thoracic drainage were
studied retrospectively. RB was found in 70 of 79 (88.6%) smokers operated for
spontaneous pneumothorax. Associated interstitial pathological abnormalities were
present in 53 of 79 cases (67.1%). In nine patients, the pathological lesions
were severe and resembled desquamative interstitial pneumonia. Emphysematous
lesions were present in about one-third of the patients. Although the possible
pathophysiological consequences of respiratory bronchiolitis remain speculative,
this study demonstrates the high prevalence of this pathological abnormality in
patients with pneumothorax requiring surgical treatment.
PMID- 9762804
TI - Many faces of pulmonary aspergillosis.
AB - Aspergillus is a ubiquitous fungus. It is commonly isolated as an upper
respiratory tract saprophyte and is the most frequent contaminant in laboratory
specimens. Because species of aspergillus are omnipresent, one must be cautious
in ascribing a causal role to the fungus obtained from patients. Aspergillus has
low pathogenicity for humans and animals and rarely invades the immunologically
competent host. Although the fungus can affect any organ system, the respiratory
tract is involved in >90% of afflicted patients. Pulmonary aspergillosis,
depending whether the host is atopic or immunosuppressed, may be classified under
four categories: allergic or hypersensitivity syndromes, saprophytic
colonization, invasive (infective) dissemination, and chemical or toxic
pneumonitis. These entities differ clinically, radiologically, immunologically,
and in their response to various therapeutic agents. An increased awareness, an
aggressive approach to securing the diagnosis, and instituting early and
appropriate therapy are needed to reduce the high morbidity and mortality caused
by many of the aspergillus-related syndromes.
PMID- 9762806
TI - Deep breathing and awake apnoea in a patient who had recurrent hypoxaemia and
hypercapnia without sleep apnoea.
AB - A 21 yr old with deep breathing and awake apnoea, who had recurrent hypoxaemia
and hypercapnia without sleep apnoea, was presented. Although the organic
abnormality responsible for the breathing disturbance was not found,
administration of acetazolamide facilitated several breaths between sighs, and
the patient's hypoxaemia with hypercapnia improved. Some patients who have
abnormalities in the cortical control of breathing that cannot be detected by
present methods of examination may experience some improvement in breathing with
the administration of chemical stimulants such as acetazolamide.
PMID- 9762805
TI - Sarcoidosis: immunopathogenetic concepts and their clinical application.
AB - Our understanding of the immunopathogenesis of sarcoidosis has been advanced by
studies of bronchoalveolar lavage cells. Activated macrophages and T-cells have
been identified in different compartments of the sarcoid lung and the
characteristics of the activation suggest that the cells become activated in the
course of a normal immune response. The immune cells communicate via a cytokine
network and the measuring of cytokine levels yields subgroups of sarcoidosis
patients with different courses of the disease indicating different states of
activation of the disease-mediating immune cells. The causative agent of
sarcoidosis has not yet been identified; however, some of the described
mechanisms can be clinically applied either to detect patients at risk of
deterioration or to develop new therapeutic strategies. Using these approaches
methotrexate, pentoxifylline and thalidomide have been identified as drugs which
effectively suppress sarcoid inflammation and the serum level of soluble
interleukin-2 receptors has been delineated to be a serum marker of sarcoid
inflammation. Furthermore, analysing the pulmonary cytokine network in
sarcoidosis will yield new staging parameters possibly supplying prognostic
information and guiding therapeutic intervention.
PMID- 9762807
TI - A case of respiratory muscle weakness due to cytochrome c oxidase enzyme
deficiency.
AB - Mitochondrial myopathy is a rare cause of dyspnoea and respiratory failure,
usually presenting in infancy. We describe a 27 yr old woman with a partial
cytochrome c oxidase enzyme deficiency causing respiratory muscle weakness and
respiratory failure. The onset was acute, with no preceding respiratory symptoms.
The patient was successfully treated with bilevel positive airway pressure
therapy.
PMID- 9762808
TI - Polypoid bronchial lesions due to Scedosporium apiospermum in a patient with
Mycobacterium avium complex pulmonary disease.
AB - A 69 yr old female was hospitalized for further examination of abnormal shadows
on chest radiographs. She had a history of tuberculous pleurisy, rheumatoid
arthritis and gold-induced interstitial pneumonia. On admission she still
suffered from rheumatoid arthritis. A chest computed tomography scan on admission
showed clusters of small nodules in subpleural regions of both lungs combined
with bronchiectasis. Mycobacterium avium complex was cultured repeatedly from the
sputum. Bronchoscopic examination disclosed white-yellow polypoid lesions in the
orifice of the left B4 bronchus. Cultures of the brushing specimen of the
polypoid lesions and bronchial aspirates from the B4 bronchus yielded smoky-grey
mycelial colonies that were later identified as Scedosporium apiospermum. It was
concluded that the polypoid bronchial lesions due to Scedosporium apiospermum
were formed in the preexisting dilated bronchus caused by Mycobacterium avium
complex pulmonary disease.
PMID- 9762809
TI - Half-night polysomnography: how is it compared to full-night polysomnography?
PMID- 9762810
TI - Sarcoid granulomatosis after zirconium exposure with multiple organ involvement.
PMID- 9762811
TI - Dermatology resources on the internet: a practical guide for dermatologists.
PMID- 9762812
TI - Tinea versicolor.
PMID- 9762813
TI - The prognosis of patients with basal and squamous cell carcinoma of the skin.
PMID- 9762814
TI - Amyopathic dermatomyositis in Hong Kong -- association with nasopharyngeal
carcinoma.
AB - BACKGROUND: Amyopathic dermatomyositis (ADM) is a rare variant of dermatomyositis
(DM) in which there is no apparent muscle involvement at initial presentation,
but clinical and laboratory evidence of myopathy may appear later. Like DM, it
has a known association with malignancy. OBJECTIVE: To record the occurrence of
ADM in Hong Kong during the period from January 1988 to June 1996, and to
establish the types of carcinoma with which it is associated. METHODS: The
records of all patients diagnosed with ADM in three major dermatology clinics in
Hong Kong were retrospectively studied to confirm the diagnosis and to look for
any associated malignancy at any stage of the disease. RESULTS: Between 1988 and
1996, six patients in Hong Kong (five men and one woman; mean age, 50 years)
fulfilled the criteria of ADM. During a follow-up period ranging from 20 to 90
months (average, 35.6 months), none developed any evidence of myositis.
Associated malignancy was found in the five male patients. There were three cases
of nasopharyngeal carcinoma (NPC), one case of non-small cell carcinoma of the
lung, and one case of metastatic carcinoma of the cervical lymph node of unknown
primary. No carcinoma had developed in the female patient during a follow-up
period of 90 months. CONCLUSIONS: There is a strong association between ADM and
NPC in Hong Kong.
PMID- 9762815
TI - Relapsing cutaneous polyarteritis nodosa associated with streptococcal
infections.
AB - BACKGROUND: Polyarteritis nodosa is an aggressive, often fatal form of vasculitis
associated with multi-organ involvement. Cutaneous polyarteritis nodosa is
purported to be a more benign form of this disorder with involvement limited to
the skin. METHODS: The identification of a female patient from childhood to
adulthood documenting repeated episodes of cutaneous polyarteritis nodosa
following bouts of recurrent streptococcal pharyngitis. RESULTS: Repeated bouts
of streptococcal pharyngitis at ages 11, 28, and 33 years were followed by
episodes of cutaneous polyarteritis nodosa, documented by histopathologic skin
changes and clinical presentation, and confirmed by therapeutic management.
CONCLUSIONS: Various infectious and non-infectious conditions have been linked
both to the initiation and relapse of this disease. We describe a patient with
recurrent episodes of cutaneous polyarteritis nodosa spanning a period of over 20
years with each episode appearing to be linked to a prior streptococcal
infection.
PMID- 9762816
TI - Erythema nodosum and associated diseases. A study of 129 cases.
AB - BACKGROUND: Erythema nodosum (EN) is associated with many infectious diseases.
The purpose of this study was to evaluate the relative prevalence of associated
diseases in a large series of EN, and to review the previously described causes
of EN. MATERIALS AND METHODS: A total of 157 inpatients with a diagnosis of EN
made in Strasbourg, France between 1960 and 1995 were studied retrospectively,
but only 129 patients with confirmed EN were evaluated. A biopsy was taken in 30
patients with atypical clinical symptoms. Chest radiography, blood cell count,
throat swab, and anti-streptolysin dosage were performed systematically. Viral
investigations and serodiagnoses for various bacterial infections were carried
out in approximately half of the patients. All investigations were analyzed
retrospectively and compared with the world literature. RESULTS: The female: male
ratio was 5 : 1 and the mean age was 31 years. We found 28% confirmed
streptococcal infections, 11% sarcoidosis, 1.5% enteropathies, 1.5% Chlamydia
infections, 0.8% Mycoplasma infections, 0.8% Yersinia infections, 0.8% hepatitis
B, and 0.8% tuberculosis (one case). The causative factor could not be determined
in 55% of patients. CONCLUSIONS: Our data confirm the predominance of
streptococcal infections and sarcoidosis among patients with EN. Tuberculosis has
virtually disappeared, since the last case was observed in 1962. Various viral or
bacterial diseases are rarely associated with EN, but all patients were not
thoroughly investigated. A large and prospective study should be performed in
order to determine the true prevalence of associated diseases in EN. In the
absence of specific symptoms, exhaustive investigations are not cost-effective.
PMID- 9762817
TI - Skin diseases in Bamako (Mali).
AB - BACKGROUND: Skin diseases have only recently been considered as a possible public
health problem in developing countries. Data supporting this matter are scarce.
The aim of this study is to report the experience of a specialized dermatologic
center in Bamako (Mali) in order to complete two previous studies conducted in
the Bamako area: a prevalence study in the general population and a study in
nonspecialized health centers of Bamako. It is our intention to provide a
comprehensive picture of the problem of skin diseases in an African developing
country. METHODS: We retrospectively collected all cases of skin diseases
diagnosed during consultations provided at the Institut Marchoux in Bamako, the
only center specializing in dermatology in Mali, during the year 1993. RESULTS: A
total of 10,575 new outpatients were seen with 10,889 skin diseases. The main
skin diseases registered were as follows: infectious dermatoses (41% of all
diagnoses, including scabies (16.6%), superficial mycoses (13.6%), and primary
pyoderma (5.6%)), dermatitis (20.4%), papular urticaria (4.4%), acne (4.2%),
pityriasis alba (3.6%), keratoderma (3.6%), and urticaria (3%). Typical tropical
infectious diseases accounted for only 1% of all diagnoses. CONCLUSIONS: It
appears that certain skin diseases (mainly scabies and pyoderma) are an important
health problem for the population of the Bamako area. Public health policies
should be implemented in order to manage this problem rationally.
PMID- 9762818
TI - Frequency of pre-existing actinic keratosis in cutaneous squamous cell carcinoma.
AB - BACKGROUND: Controversy over the rate of malignant transformation of actinic
keratosis (AK) into cutaneous squamous cell carcinoma (SCC) has generated
considerable debate regarding the importance of treating all such precancers to
preclude their transofrmation. Current changes in US healthcare policy will deny
many individuals access to certain simple and effective treatment modalities for
precancerous lesions. OBJECTIVE: Our purpose was to determine whether there is a
significant association between the presence of cutaneous SCC and pre-existing
AK. METHODS: One hundred and sixty five consecutive cases of cutaneous SCC,
retrieved from the files of a university-affiliated dermatopathology laboratory
serving north-central Florida, were selected for review by a single
dermatopathologist (D.M.). Hematoxylin and eosin stained skin tissue slides were
examined under light microscopy for the presence of AK in close proximity to, or
giving rise to, cutaneous SCC. RESULTS: Of the 165 cutaneous SCC cases reviewed,
82.4% (136 out of 165) were found to have concomitant AK giving rise to and/or in
close proximity to SCC. Of the 136 AK-positive SCC cases, 26.7% (44) were
identified as superficial SCC arising within an AK (AKSSCC) and 55.7% (92) had AK
in close proximity to SCC (AK + SCC). Close proximity is defined to include AK
changes located directly adjacent to (on the shoulder of) SCC, to a maximum
distance of 8 mm away. CONCLUSIONS: The 82.4% prevalence of concomitant AK and
cutaneous SCC in our biopsy population suggests a strong correlation between
these two lesions. The fact that 26.7% of these lesions had SCC arising from AK
highlights the importance of early recognition and effective treatment for AK.
PMID- 9762819
TI - Detection and differentiation of causative fungi of onychomycosis using PCR
amplification and restriction enzyme analysis.
AB - BACKGROUND: Onychomycosis, a fungal nail infection, has become one of the most
important dermatophytoses. Unfortunately, a predictably successful diagnostic
approach to onychomycosis does not yet exist. OBJECTIVE: The purpose of this
study was to develop a deoxyribonucleic acid (DNA)-based diagnostic method to
improve the sensitivity and specificity of the detection and differentiation of
the pathogenic fungi of onychomycosis. METHODS: We attempted to detect fungi in
the nail using polymerase chain reaction (PCR) primer systems that were designed
in conserved sequences of the small ribosomal subunit 18S-rRNA genes shared by
most fungi, and differentiated between species by restriction enzyme analysis of
the amplified product. RESULTS: Fragments of the gene coding for 18S-rRNA were
amplified successfully from medically important fungi species, but not from
normal nails. Restriction fragment length polymorphism patterns using HaeIII
endonuclease were sufficiently different to allow the recognition of individual
species. CONCLUSIONS: The PCR-restriction enzyme analysis method appears to be a
more sensitive detection and identification technique for onychomycosis than
conventional methods, and has considerable diagnostic value.
PMID- 9762820
TI - Unusual presentation of cutaneous vasculitis.
PMID- 9762821
TI - Kasabach-Merritt syndrome in two successive pregnancies.
PMID- 9762822
TI - Pachydermoperiostosis with cutaneous squamous cell carcinomas.
PMID- 9762823
TI - Follicular cysts and hyperkeratoses in early mycosis fungoides.
PMID- 9762824
TI - Solitary hyperpigmented island in a sea of elastosis (anelastosis).
PMID- 9762825
TI - Localized hyperhidrosis treated with aluminum chloride in a salicylic acid gel
base.
PMID- 9762826
TI - A comparison of the efficacy of oral fluconazole, 150 mg/week versus 50 mg/day,
in the treatment of tinea corporis, tinea cruris, tinea pedis, and cutaneous
candidosis.
PMID- 9762827
TI - Response of segmental vitiligo to 0.05% clobetasol propionate cream.
PMID- 9762828
TI - Early repeeling--a matter of time.
AB - BACKGROUND: Repeeling after a short interval in medium-depth or deep peeling is
considered by most experts as hazardous, and is generally contraindicated. Most
experts recommend an interval of 6 months or more before repeating the same level
of peel. The results are presented of four patients who underwent repeeling after
a short interval. METHODS AND RESULTS: All four patients were dissatisfied with
their first peel (medium-depth peel performed with trichoroacetic acid (TCA)
35%). Repeelings were performed using two methods: TCA 30-35% (Cases 1-3) and
unoccluded Baker phenol peel (Case 4). On three occasions (Cases 1-3), the
patients underwent three peelings at short intervals. All four cases gave
excellent objective results. CONCLUSIONS: The risk of a second peel shortly after
the first is not as high as indicated in the literature, and should not be
automatically ruled out. In a selected group of patients who, for various
reasons, be persuaded to wait, repeeling after a short interval (2-3 weeks) may
solve certain problems and may even make the difference between an unhappy
patient and a satisfied one. In performing repeeling after a short interval, one
should take into consideration that the skin, particularly the keratin layer, is
thinner, so that the degree of penetration of the second peel solution and the
peel depth will be greater. It is possible that the scarring reported after
repeeling is a result of the disregard of this important factor and,
consequently, the use of too high a concentration of peel solution in the second
peel procedure.
PMID- 9762830
TI - Wound measurement by computer-aided design (CAD): a practical approach for
software utility.
PMID- 9762829
TI - Pustular eruption in a malaria patient treated with chloroquine.
PMID- 9762831
TI - Eccrine squamous syringometaplasia in a patient with phytophotodermatosis.
PMID- 9762832
TI - Balneotherapy for rheumatic diseases at the Dead Sea.
PMID- 9762834
TI - Longitudinal melanonychia associated with fluconazole therapy.
PMID- 9762833
TI - Porphyria cutanea tarda in a human immunodeficiency virus-infected patient:
treatment with N-acetyl-cysteine.
PMID- 9762835
TI - Ensuring the survival of the clinician-scientist.
PMID- 9762836
TI - Cell cycle proteins in glomerular disease.
PMID- 9762837
TI - Are there new activity markers of glomerular inflammation? A renal pathologist's
view.
PMID- 9762838
TI - Molecular genetics and clinical phenotype in heritable disorders of tubular Na+
transport.
PMID- 9762839
TI - Molecular pathophysiology of inborn renal Na+ transport defects.
PMID- 9762840
TI - Pathogenetic and regenerative mechanisms in acute tubular necrosis.
PMID- 9762841
TI - Histological characteristics of interstitial renal allograft rejection.
PMID- 9762842
TI - Cloning of a human renal p-aminohippurate transporter, hROAT1.
PMID- 9762843
TI - Cytoskeletal basis for epithelial polarity.
PMID- 9762844
TI - Cell volume-regulated gene transcription.
PMID- 9762845
TI - Angiotensin II receptors in the kidney.
PMID- 9762846
TI - Neural control of kidney function.
PMID- 9762847
TI - Epithelial sodium channel and its implication in the control of blood pressure.
PMID- 9762848
TI - Atomic force microscopy on living cells: aldosterone-induced localized cell
swelling.
PMID- 9762849
TI - Transforming growth factor beta signal transduction in the kidney.
PMID- 9762850
TI - G proteins and hypertension.
PMID- 9762851
TI - Regulation of NO synthesis in endothelial cells.
PMID- 9762852
TI - Determination of glomerular permselectivity: is it useful for diagnosis and
clinical management of patients with glomerular disease?
PMID- 9762853
TI - Injury mechanisms in vasculitis.
PMID- 9762854
TI - Target blood pressure in the treatment of essential hypertension.
PMID- 9762855
TI - Pregnancy-induced alterations in renal function.
PMID- 9762856
TI - Tubulotoxic mechanisms of ochratoxin A.
PMID- 9762857
TI - Endothelial cell markers in vasculitis.
PMID- 9762858
TI - New diagnostic and therapeutic aspects in IgA nephropathy.
PMID- 9762859
TI - NKF-DOQI guidelines--will they change the treatment of dialysis patients in
Germany? National Kidney Foundation. Dialyses Outcomes Quality Initiative.
PMID- 9762860
TI - Causes of coronary heart disease in patients on renal replacement therapy.
PMID- 9762861
TI - Epidemiology, pathogenesis and therapeutic modalities in hemolytic-uremic
syndrome.
PMID- 9762862
TI - Prothrombotic risk factors and acute kidney transplant rejection.
PMID- 9762863
TI - Effects of botulinum neurotoxin type A on the expression of gephyrin in cat
abducens motoneurons.
AB - In this study, we investigated the effects of long-term synaptic blockade on
postsynaptic receptor clustering at central inhibitory glycinergic synapses. High
doses of botulinum neurotoxin type A injected in the lateral rectus muscle
completely abolishes inhibitory postsynaptic potentials onto abducens motoneurons
within 2 days postinjection, and transmission remains blocked for at least 2
months. Using this model, we analyzed the expression of gephyrin, a glycine
receptor clustering protein, on the membrane of motoneuron somata after botulinum
neurotoxin type A injection in their target muscle. Immunofluorescence or
electron microscopy immunohistochemistry revealed gephyrin-immunoreactive
clusters (most < 0.5 microm in diameter) densely covering the surface of control
abducens motoneurons. Ultrastructurally, presynaptic terminals containing
flattened synaptic vesicles (F terminals) were found associated with multiple
gephyrin-immunoreactive postsynaptic densities (average 1.24 gephyrin clusters/F+
profile). No significant changes in gephyrin-immunoreactive clusters were
observed at 5 days postinjection, but we found significant reductions (25-40%) in
the density of gephyrin clusters 19 and 35 days postinjection. Hence, the
physiological alterations reported in this model precede structural changes on
postsynaptic receptor cluster density. The decrease in gephyrin-immunoreactive
clusters was paralleled by reductions in synaptic covering (F+ terminals per 100
microm of membrane). Presumed inactive F+ terminals that remained attached to the
motoneuron surface displayed normal gephyrin-immunoreactive clusters; however,
the pre- and postsynaptic membranes in between synaptic active zones frequently
appeared separated by enlarged extracellular spaces. We concluded that
postsynaptic receptor cluster dissolution seemed more directly related to
terminal retraction than to inactivity alone.
PMID- 9762864
TI - Cortical connections of the dorsomedial visual area in new world owl monkeys
(Aotus trivirgatus) and squirrel monkeys (Saimiri sciureus).
AB - The dorsomedial visual area (DM) is an extrastriate area that was originally
described in owl monkeys as a complete representation of the visual hemifield in
a heavily myelinated wedge of cortex just rostral to dorsomedial visual area V2.
More recently, connections of DM in owl monkeys have been described (Krubitzer
and Kaas [1993] J. Comp. Neurol 334:497-528). As part of an effort to determine
whether DM exists in other primates, we compared the architecture, connections,
and visual topography of DM in owl monkeys and the presumptive DM in squirrel
monkeys. In both species of New World monkeys, the DM region was more heavily
myelinated than adjacent cortex, and this region was connected with the first and
second visual areas, the middle temporal area (MT), the medial area, the ventral
posterior parietal area, the dorsointermediate area, the dorsolateral area, the
ventral posterior and ventral anterior areas, the medial superior temporal area,
the fundal area of the superior temporal sulcus, the inferior temporal cortex,
and frontal cortex in or near the frontal eye field. In squirrel monkeys, both
blob and interblob regions of V1 contributed equally to DM, whereas the blob
regions provided most of the projections to V1 in owl monkeys. In squirrel
monkeys, connections were also found with cortex on the ventral surface in the
ventral occipital temporal sulcus. In owl monkeys and squirrel monkeys,
connections were with both the upper and lower visual field representations in
V1, V2, and MT, demonstrating that DM contains a complete representation of the
visual field. These similarities in architecture, connections, and retinotopy
argue that DM is a visual area of both owl and squirrel monkeys.
PMID- 9762865
TI - Combinatorial odor discrimination in the brain: attractive and antagonist odor
blends are represented in distinct combinations of uniquely identifiable
glomeruli.
AB - The rules governing the central discrimination of odors are complex and poorly
understood, but a growing body of evidence supports the hypothesis that olfactory
glomeruli may represent functionally distinct coding modules in the brain.
Testing this hypothesis requires that both the functional characteristics and the
spatial position of the glomerulus under study be uniquely identifiable. To
address these questions, we examined a specialized array of glomeruli (the
macroglomerular complex; MGC) in the antennal lobe of male moths that receives
input from olfactory receptor cells tuned specifically to female-released
odorants that either promote upwind flight (conspecific sex pheromones) or
inhibit it (interspecific antagonists). By using a three-dimensional
reconstruction method based on high-resolution laser-scanning confocal
microscopy, we generated precise spatial maps of the MGC glomeruli in two related
noctuid species with similar pheromone chemistry, Heliothis virescens and
Helicoverpa zea. To determine the breadth of tuning of individual MGC glomeruli
in processing information about these social signals, we used intracellular
recording and staining methods to examine the responses of projection (output)
neurons that innervate MGC glomeruli and that each project an axon to higher
integrative centers. In both species, a close correspondence was found between
the odor specificity of the projection neurons and the glomerulus (or glomeruli)
supplied by them. The binary blend of pheromone components for each species was
represented by neural activity in only two distinct glomeruli in both H.
virescens and H. zea. Odorants that antagonize upwind flight when they are added
to the respective pheromonal blends evoked excitatory activity in output neurons
restricted to a third glomerulus in the MGCs of both species. In summary, these
results suggest that the selective activation of different combinations of
functionally distinct MGC glomeruli is a general means for discriminating these
specific attractant and antagonist chemical signals in the brain.
PMID- 9762866
TI - Expression of insulin-like growth factors and corresponding binding proteins
(IGFBP 1-6) in rat spinal cord and peripheral nerve after axonal injuries.
AB - Insulin-like growth factors (IGFs) exert trophic effects on several different
cell types in the nervous system, including spinal motoneurons. After peripheral
nerve injury, the increased expression of IGFs in the damaged nerve has been
suggested to facilitate axonal regeneration. Here we have examined the expression
pattern of mRNAs encoding IGF-1 and and -2, IGF binding proteins (IGFBPs) 1-6 in
the rat spinal cord and peripheral nerve in three lesion models affecting lumbar
motoneurons, i.e., sciatic nerve transection, ventral root avulsion, and a cut
lesion in the ventral funiculus of the spinal cord. The expression was also
studied in enriched Schwann cell and astrocyte cultures. The injured sciatic
nerve expressed IGF-1 and IGF-2 as well as IGFBP-4 and IGFBP-5, whereas central
nervous system (CNS) scar tissue expressed IGF-1, IGFBP-2, and IGFBP-5. IGFBP-6
mRNA was strongly upregulated in spinal motoneurons after all three types of
lesions. IGFBP-6-like immunoreactivity was present in motoneuron cell bodies,
dendrites in the ventral horn, and axons in the sciatic nerve. In line with the
in vivo findings, cultured Schwann cells expressed IGF-1, IGF-2, IGFBP-4, and
IGFBP-5 mRNAs, whereas cultured astrocytes expressed IGF-1, IGFBP-2, and IGFBP-5
mRNAs. These findings show that IGF-1 is available for lesioned motoneurons both
after peripheral and central axonal lesions, whereas there are clear differences
in the expression patterns for IGF-2 and some of the binding proteins in CNS and
peripheral nervous system (PNS) scar tissue. The robust upregulation of IGFBP-6
mRNA in lesioned motoneurons suggests that this binding protein may be of special
relevance for the severed cells.
PMID- 9762867
TI - Cellular distribution of ferritin subunits in postnatal rat brain.
AB - The normal development of the brain requires finely coordinated events, many of
which require iron. Consequently, iron must be available to the brain in a timely
manner and in a bioavailable form. However, the brain also requires stringent
mechanisms to protect itself from iron-induced oxidative damage. The protein that
is best suited to making iron available but also adequately protecting the cell
is the intracellular iron storage protein ferritin. Typically, ferritin is
composed of 24 subunits of H and L chains, which are functionally distinct. This
study was undertaken to determine the expression of ferritin subunits during
normal development of the postnatal rat brain. There is a shift in ferritin
containing cell types during development from predominantly microglia at
postnatal day 5 (PND 5) to predominantly oligodendrocytes by PND 30. At PND 5,
microglia are found throughout gray and white matter areas of the brain, but only
amoeboid microglia in discrete foci in the subcortical white matter are ferritin
positive. At PND 15, some oligodendrocytes in the subcortical white matter
express ferritin, but the majority of ferritin-containing cells within white
matter are still microglia. By PND 30, the predominant ferritin-containing cell
type within white matter are oligodendrocytes. Generally, the cellular
distribution of both ferritin subunits were identical with one major exception; H
ferritin, but not L-ferritin, was present in neuronal nuclei in the cortex. These
data suggest that microglia play a role in brain iron homeostasis during normal
postnatal development and may influence myelination by competing with
oligodendrocytes for iron.
PMID- 9762868
TI - Postmortem tracing reveals the organization of hypothalamic projections of the
suprachiasmatic nucleus in the human brain.
AB - The suprachiasmatic nucleus (SCN) is a small structure considered to be the site
of the major circadian pacemaker of the mammalian brain. Disturbances in human
biological clock function may occur in several diseases, such as Alzheimer's
disease, sleep problems, and seasonal depression. Since basic knowledge of the
anatomical connections of the human SCN is limited due to the lack of suitable
neuroanatomical tracing methods, the understanding of physiological mechanisms of
human SCN function has obviously been hampered. In the present study, the
hypothalamic connections of the human SCN were revealed for the first time with a
newly developed in vitro postmortem anterograde tracing method. The human SCN was
found to be connected with nuclei in the hypothalamus that are involved in
hormone secretion, cardiovascular regulation, and behavior activity. These human
SCN projections appear to follow the same general patterns as those in the rodent
brain. This homology may indicate an evolutionary conservation of the SCN
projections from rodent to human. Through these connections, the human SCN may
transmit its circadian information to regulate hormone secretion, body
temperature, and behavioral functions as it does in animal species. In addition,
the postmortem tracing technique may be a valuable tool that will contribute to
our understanding of anatomical connections in the human brain, and may have
other applications in the research on the physiology and pathology of the human
brain.
PMID- 9762869
TI - Synaptic changes in the perineal motoneurons of aged male rats.
AB - Cholera toxin-horseradish peroxidase (CT-HRP) was injected into the
bulbocavernosus muscles of young (2 months of age) and old (19-20 months of age)
male rats, and animals were killed 2 days later. The spinal cords containing the
spinal nucleus of the bulbocavernosus (SNB) were dissected, processed with a
modified tetramethylbenzidine method for visualization of retrogradely
transported CT-HRP, and examined ultrastructurally. Neuronal structures apposing
the membranes of 120 CT-HRP-labeled SNB motoneurons were analyzed by measuring
the percentage of somatic membranes covered by synaptic contacts, synaptoid
contacts, and neuron-neuron contacts. Most of the neuronal structures in the
young and old SNB motoneurons consisted of synaptic contacts. The mean percentage
of somatic membranes covered by synapses in old rats was significantly smaller
than that in young ones. Size and number of synaptic contacts per unit length of
somatic membranes in old animals were also significantly reduced. Plasma levels
of testosterone in old males were significantly smaller than those in young ones.
These age-related changes in synaptic inputs to SNB motoneurons and plasma levels
of androgen seem to correlate with aging of the SNB system.
PMID- 9762870
TI - Increased number and size of dendritic spines in ipsilateral barrel field cortex
following unilateral whisker trimming in postnatal rat.
AB - The barrel field area of the primary somatosensory cortex of rodents is a fertile
ground for investigating experience-dependent plasticity and its mechanisms,
because the neurons in its layer IV are distributed in groups (barrels) which
correspond somatotopically to the vibrissae of the contralateral facial pad.
After removal of three rows of whiskers from the right facial pad of young rats
during the first two postnatal months, we looked for eventual changes in
dendritic spine number and morphology in the corresponding barrels ipsi- and
contralateral to the deprivation. Intact littermate controls were also examined.
Spine number was determined by means of the unbiased disector method in electron
micrographs from serial thin sections processed for post-embedding gamma
aminobutyric acid (GABA) immunocytochemistry. The volume and surface area of
spine head, surface area of postsynaptic density and length of spine neck were
measured from computerized three-dimensional reconstructions. Even though there
was no significant side-to-side difference in the numerical density of dendritic
spines in the experimental animals, the total number of spines in the ipsilateral
barrels had increased by 67%, in view of the greater thickness of layer IV on
this side. Moreover, spine head volume and surface area of postsynaptic densities
were increased, and the length of spine neck was reduced in the ipsilateral
compared to the contralateral cortex, and similar differences were noticeable
between ipsilateral and control cortex. These changes apparently involved not
only the predominant population of relatively small, dendritic spines innervated
by asymmetrical synaptic terminals, but also the relatively small contingent of
larger spines receiving symmetrical synapses formed by GABA terminals. The most
likely explanation for such ipsilateral changes was an increased use of the
intact (contralateral) facial pad during postnatal life, in keeping with the
notion that activation of a peripheral sensory apparatus during the early
postnatal period may have profound effects on the neuronal morphology and
structural design of the primary somatosensory cortex. A possible mechanism in
this case might be the excessive early activation of thalamic afferents,
resulting in increased production of trophic factors, such as brain-derived nerve
growth factor.
PMID- 9762871
TI - Cells of origin of the trigeminohypothalamic tract in the rat.
AB - Recent studies have demonstrated that a large number of spinal cord neurons
convey somatosensory and visceral nociceptive information directly from cervical,
lumbar, and sacral spinal cord segments to the hypothalamus. Because sensory
information from head and orofacial structures is processed by all subnuclei of
the trigeminal brainstem nuclear complex (TBNC) we hypothesized that all of them
contain neurons that project directly to the hypothalamus. In the present study,
we used the retrograde tracer Fluoro-Gold to examine this hypothesis. Fluoro-Gold
injections that filled most of the hypothalamus on one side labeled approximately
1,000 neurons (best case = 1,048, mean = 718 +/- 240) bilaterally (70%
contralateral) within all trigeminal subnuclei and C1-2. Of these neurons, 86%
were distributed caudal to the obex (22% in C2, 22% in C1, 23% in subnucleus
caudalis, and 18% in the transition zone between subnuclei caudalis and
interpolaris), and 14% rostral to the obex (6% in subnucleus interpolaris, 4% in
subnucleus oralis, and 4% in subnucleus principalis). Caudal to the obex, most
labeled neurons were found in laminae I-II and V and the paratrigeminal nucleus,
and fewer neurons in laminae III-IV and X. The distribution of retrogradely
labeled neurons in TBNC gray matter areas that receive monosynaptic input from
trigeminal primary afferent fibers innervating extracranial orofacial structures
(such as the cornea, nose, tongue, teeth, lips, vibrissae, and skin) and
intracranial structures (such as the meninges and cerebral blood vessels)
suggests that sensory and nociceptive information originating in these tissues
could be transferred to the hypothalamus directly by this pathway.
PMID- 9762872
TI - Combining studies using effect sizes and quality scores: application to bone loss
in postmenopausal women.
AB - This article presents a random effects model that uses effect sizes (ES) and
quality scores to integrate results from investigations. An empirical example is
given with data obtained from a meta-analysis on the effectiveness of physical
activity in the prevention of bone loss in healthy postmenopausal women. A
Medline search was performed to locate relevant studies published in French or
English between January 1966 and May 1996. Three independent reviewers extracted
data from studies. Effect sizes were calculated according to the method of Hedges
and Olkin. A modified version of Chalmers' scale was utilized to calculate
quality scores. DerSimonian and Laird's method with incorporation of the quality
scores was used to estimate the overall effect size. Quality scores and the
inverse of the variances were included as weights when combining studies. The
overall estimate and standard error (SE) of the effect of physical activity on
spinal bone mineral density loss in healthy postmenopausal women was ESoverall =
0.4263 (1.1361). When compared to other meta-analysis methods such as the fixed
effects model and the model of DerSimonian and Laird without the quality score
(DL), the new model generated comparable estimators (fixed effects model's
ESoverall (SE) = 1.2724 (0.0139), DLs ESoverall (SE) = 0.3958 (1.2370)). Due to
the heterogeneity that existed between studies, a random effects model was more
appropriate then a fixed effects model. However, it resulted in wider confidence
intervals, as expected. It was shown empirically that the model using quality
scores generated narrower confidence intervals than the model of DL alone. The
inclusion of covariates such as quality scores in meta-analyses permits the
quantification of the variation between studies.
PMID- 9762873
TI - Using binary logistic regression models for ordinal data with non-proportional
odds.
AB - The proportional odds model (POM) is the most popular logistic regression model
for analyzing ordinal response variables. However, violation of the main model
assumption can lead to invalid results. This is demonstrated by application of
this method to data of a study investigating the effect of smoking on diabetic
retinopathy. Since the proportional odds assumption is not fulfilled, separate
binary logistic regression models are used for dichotomized response variables
based upon cumulative probabilities. This approach is compared with polytomous
logistic regression and the partial proportional odds model. The separate binary
logistic regression approach is slightly less efficient than a joint model for
the ordinal response. However, model building, investigating goodness-of-fit, and
interpretation of the results is much easier for binary responses. The careful
application of separate binary logistic regressions represents a simple and
adequate tool to analyze ordinal data with non-proportional odds.
PMID- 9762874
TI - Selective opportunistic screening for hypercholesterolemia in primary care
practice.
AB - OBJECTIVES: To assess the performance of selective opportunistic screening in a
primary care group practice. DESIGN: Cross-sectional survey of coronary heart
disease risk factors and retrospective chart audit of cholesterol testing.
SETTING: Capitation-funded primary care group practice in Ontario, Canada.
SUBJECTS: 7785 enrolled patients between the ages of 20 and 69 years.
INTERVENTION: Protocol-based selective opportunistic screening program for
hypercholesterolemia of 45 months duration. MAIN OUTCOME MEASURES: Targeting
(proportion of screening tests that were appropriate), coverage (proportion of
those meeting screening criteria who had a screening test performed), over
screening (proportion of those not meeting screening criteria who had a screening
test performed), and screening ratio (likelihood that a screening test was
performed on an individual who met screening criteria rather than one who failed
to meet screening criteria). RESULTS: 64.7% of patients tested met the practice
criteria for screening. 37.7% of patients who met the practice screening criteria
were tested and 24.9% of those not meeting practice screening criteria had a
cholesterol test performed. The screening ratio was 1.52. CONCLUSION: Our
findings bring into question the effectiveness of opportunistic approaches to
preventive care.
PMID- 9762875
TI - Testing the measurement properties of the Short Form-36 Health Survey in a frail
elderly population.
AB - The Short Form-36 Health Survey (SF-36) is a widely used measure of health
related quality of life, however, its suitability for frail older persons is not
well documented. This study examines the measurement properties of the SF-36 in a
frail older patient population. Patients consecutively admitted to two geriatric
services (n = 146) were administered the SF-36 and comparative measures on
admission and discharge. Internal consistency (0.75-0.91) and test-retest
reliability (0.24-0.80) did not meet standards for clinical application of the
tool. Four subscales were moderately correlated with comparative measures
(Physical Function 0.53 to -0.76; Bodily Pain -0.61; Vitality -0.58; Mental
Health -0.63). The results of effect size, standardized response mean, and
relative efficiency statistics were consistent in documenting only minimal change
for the SF-36 subscales. The SF-36 appears to be reliable and valid, although its
ability to monitor clinical change for frail older patients is questionable.
PMID- 9762876
TI - Predictors of sex hormone levels among the elderly: a study in Greece.
AB - This study examines the relationship between a series of epidemiologic parameters
(age, height, body mass index (BMI), smoking, alcohol consumption, and coffee
drinking) and serum concentrations of testosterone, estradiol, sex hormone
binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS). Among 52
healthy, elderly Greek men, we observed that serum levels of DHEAS decreased with
increasing age [19% decline per 5-year increase in age, 95% CI, -2.1-(-33.5)],
obesity [48% decline for BMI >30 kg/m2 compared to <27 kg/m2, CI, -15.7-(-68.7)],
and current smoking [37% decline compared to nonsmokers, CI, -9.5-(-57.2)].
Estradiol concentrations increased with increasing BMI [77.1% increase for BMI
>30 kg/m2 compared to <27 kg/m2, CI, -12.0-256.3], alcohol drinking [66% increase
for > or = 7 glasses/week compared to <7 glasses/week, CI, 4.4-164.4], and coffee
drinking [59% increase for > or = 14 cups/week compared to > or = 14 cups/ week,
CI, -0.5-155.9], and decreased among current smokers [40% decline compared to
nonsmokers, CI, -64.9-0.8]. SHBG was marginally positively associated with
increasing age [13% increase per 5 years, CI, -0.5-29.6]. Testosterone was
significantly related only to current smoking [27% decline compared to
nonsmokers, CI, -45.4-(-3.1)]. These findings suggest that several variables
appear to be associated with sex steroid levels and the influence of these
findings on the occurrence of hormone-related conditions warrants further
exploration.
PMID- 9762877
TI - Effectiveness of cataract surgery in Barcelona, Spain site results of an
international study. Barcelona I-PORT investigators. International Patient
Outcomes Research Team.
AB - OBJECTIVES: To describe the impact of cataract surgery on visual function and
health status in terms of clinical indicators as well as perceived health and
functional capacity, and to identify patient characteristics and differences in
clinical management that might affect outcomes. SUBJECTS AND METHODS:
Observational longitudinal study of a cohort of 218 patients aged 50 or older
undergoing first eye cataract surgery. Patients were evaluated pre- and
postoperatively by clinical examinations (visual acuity [VA], ocular and medical
comorbidity) and standardized telephone interviews. Main outcome measures
included: the VF-14 Visual Function Index, the Cataract Symptom Score (CSS), the
Sickness Impact Profile (SIP), and global measures of patients' trouble and
satisfaction with vision. RESULTS: Significant improvement in all outcomes
measures were observed at 4 months postoperatively (P < 0.001). However, the
proportion of improved patients varied according to the outcome considered: VA
(87%), CSS (72%), VF-14 (62%), and SIP (38%). Patient characteristics associated
with higher a level of improvement were: worse preoperative visual function (VA,
CSS, VF-14) (P < 0.001), less ocular comorbidity (P < 0.05), less postoperative
complications (P < 0.05) and better preoperative general health status (SIP) (P <
0.01). The differences in clinical management were not associated with the
outcomes (effectiveness) of surgery. CONCLUSIONS: A large proportion of patients
benefit from cataract surgery, the greatest gain corresponding to visual function
rather than to general health status. Since effectiveness of surgery is unrelated
to operative procedures, less costly practices (i.e., day case surgery and loco
regional anesthesia) should be promoted.
PMID- 9762878
TI - Clinical outcomes of localized melanoma of the foot: a case-control study.
AB - The controversy over whether melanoma of the foot has a poorer prognosis than
melanoma of the leg remains unresolved. This investigation used a case-control
design to address this issue. This design consisted of a survival analysis of 119
cases with localized melanoma of the foot and 238 controls with localized
melanoma of the leg that were matched on prognostic factors including tumor
thickness, ulceration, surgical treatment, gender, year of diagnosis, and age.
There was a statistically significant difference between the survival rates of
cases and controls. The 5-year survival rate for cases was 74.3% compared to
85.2% for controls. At 10 years, the survival rate was 63.6% for cases and 77.2%
for controls. Cases experienced a higher percentage of distant recurrences than
controls. These results imply that patients with melanoma of the foot have a
poorer survival than patients with melanoma of the leg after controlling for
prognostic factors.
PMID- 9762879
TI - Appendectomy in Sweden 1989-1993 assessed by the Inpatient Registry.
AB - We analyzed all appendectomies in Sweden 1989-1993 (n = 60,306) recorded in the
national Inpatient Registry. Our focus was on diagnostic accuracy, incidence rate
of appendicitis, perforative appendicitis, and length of stay by day of admission
and hospital category. The incidence rate of appendectomy decreased by 9.8% in
women compared to 4.1% in men. Since the number of patients with an end diagnosis
of appendicitis remained almost constant, diagnostic accuracy increased each
year. This was more pronounced in women than men, seen in all hospital
categories, and was higher for those admitted during periods of low capacity
(weekends/ holidays). Perforated appendicitis did not increase. Duration of
hospital stay decreased continuously, especially among the oldest. We found no
indications of an increased frequency of complications, such as increases in the
incidence rate of perforations or in the length of stay.
PMID- 9762880
TI - Health status measurement in Toxic Oil Syndrome.
AB - Toxic Oil Syndrome (TOS) is a previously unreported condition which affected more
than 20,000 people in Spain in 1981 and whose natural history is unknown. In 1993
94, a stratified random sample of 1400 survivors was drawn to measure their
health status through clinical examination and their self-perception of well
being through the Nottingham Health Profile Questionnaire (NHPQ). Two-thirds of
the sample population responded; indirect estimates suggest that selection bias
was limited. Clear and intermediate signs of neuropathy were found in one-fifth
and one-half of the patients, respectively. One-fourth and one-sixth showed some
degree of scleroderma and contractures. All conditions were more frequent in
women than in men and in age >50 than in younger ages. Although no concurrent
control group was included in the study, prevalences of these conditions are well
above expectations and are largely attributable to TOS. NHPQ scores increased
with age in both sexes up to age 50, after which they reached a plateau (with
values around 48 in men and 62 in women). Scores were associated to the
occurrence of peripheral neurological changes, contractures, and scleroderma-like
conditions. A multivariate analysis indicated age, sex, and severity of
neurological conditions as major determinants of the NHPQ scores. This overall
pattern of findings is peculiar to TOS and differs from the typical post-disaster
nonspecific syndrome.
PMID- 9762881
TI - Effect of the method of administration, mail or telephone, on the validity and
reliability of a respiratory health questionnaire. The Spanish Centers of the
European Asthma Study.
AB - The European Community Respiratory Health Survey (ECRHS), a multinational survey,
assesses and compares the prevalence of asthma among subjects, aged 20 to 44, in
several European areas. In Spain, some participating centers have used mail and
telephone as methods of questionnaire administration. The objective of the
present study was to determine whether the validity and reliability of the
questionnaire differed by method of administration. Reliability of the
questionnaire was measured with the kappa index and the odds ratio of agreement,
and validity with the sensitivity and specificity. This study found differences
in the reliability of the questionnaires although these differences were more
related to the questions themselves than to the method of administration. Among
men, but not women, mailed questionnaires were more sensitive and telephone
questionnaires more specific. We hypothesize that these differences in validity
were due to the self-selection to more severe symptomatic subjects replying
earlier and therefore to the mailed questionnaire. Combining different methods of
administration was useful as it increased participation and was an adequate
procedure to obtain information of good quality.
PMID- 9762882
TI - Assessing the feasibility of using computerized pharmacy refill data to monitor
antidepressant treatment on a population basis: a comparison of automated and
self-report data.
AB - This article compares self-report and automated data as measures of dose and
duration of antidepressant use in order to assess the feasibility of using
automated pharmacy data in a disease management context. We used self-report and
computerized refill data to identify two treatment failures-premature
discontinuation of the medication and sub-optimal dosages-at time points 1 and 4
months after initiation of antidepressant therapy. The sources showed modest
agreement regarding identification of current users at 1 month (kappa = .33);
agreement was high at 4 months (kappa = .72). Agreement regarding dosage adequacy
was also higher later in treatment, with kappas of .52 and .65 at 1 and 4 months,
respectively. The two sources showed high agreement on an overall measure of
acute phase treatment adequacy (kappa = .80). Data completeness was another
outcome, with data on current users and overall treatment adequacy generally
available from computerized files, data on dose less so. Automated pharmacy data
appear to be a feasible means of monitoring treatment adequacy and quality of
care as part of a disease management approach to improving care for populations
of patients.
PMID- 9762883
TI - Division of the colorectum into anatomic subsites: why and where?
PMID- 9762884
TI - Cancer and complexity: correlations and complementarity.
PMID- 9762885
TI - Local treatment of abdominal wound reduces tumor implantation.
AB - BACKGROUND AND OBJECTIVES: Pneumoperitoneum increases the trocar-site tumor
implantation rate using a human colon cancer cell line in a hamster model. The
purpose of this study was to determine whether local treatment of trocar sites
with potential tumoricidal agents can inhibit tumor implantation after
pneumoperitoneum. METHODS: GW-39 human colon cancer cells (0.5 ml of 2.5% v/v;
8.0 x 10(5) cells) were injected throughout the abdomen of 133 Golden Syrian
hamsters through a midline incision. The animals were randomized to receive
either untreated 5-mm trocars in each abdominal quadrant (group I control, n =
49), trocars dipped in 10% povidone-iodine (group II, n = 53), or trocars coated
with 1% silver sulfadiazine (group III, n = 51). The midline wounds were also
coated with the respective agents before closing. Pneumoperitoneum was then
maintained at 10 mmHg for 10 min, after which the trocar wounds were closed. In
group II, the trocar sites were treated with a coat of povidone-iodine after the
trocars were withdrawn and before closing. Gross and microscopic tumor implants
were analyzed at 7 weeks postoperatively. RESULTS: The rate of tumor cell
implantation at trocar sites was reduced from 93% (172/184) in the control group
to 75% (126/168) and 78% (141/180) in groups II and III, respectively (P <
0.0001). Fewer palpable tumors were detected in groups II and III (40% and 23%,
respectively) than in the control group (72%, P < 0.0001). Mean tumor mass in
group III (0.4+/-0.1 g), but not in group II (1.0+/-0.2 g), was significantly
less than that in the control group (1.3+/-0.1 g, P < 0.01). Overall tumor
involvement of the larger midline wound was similar for all groups (I = 80%, II =
79%, III = 71%). However, palpable tumors were identified more frequently in
group I (67%) than in groups II and III (43%, P < 0.05; 22%, P < 0.01,
respectively). CONCLUSION: Pretreatment of abdominal wounds with povidone-iodine
or silver sulfadiazine can reduce tumor implantation after pneumoperitoneum in a
hamster model.
PMID- 9762886
TI - Lymph node status assessment for gastric carcinoma: is the number of metastatic
lymph nodes really practical as a parameter for N categories in the TNM
Classification? Tumor Node Metastasis.
AB - BACKGROUND AND OBJECTIVES: The anatomical extent of nodal metastasis has been
replaced by the number of metastatic nodes as a key indicator of prognosis (pN
categories) in the fifth edition of Tumor Node Metastasis Classification for
gastric carcinoma by the International Union Against Cancer. The rate of
metastatic nodes among all the nodes harvested is also a good prognostic factor.
The object of this study is to evaluate which of the three parameters for the
assessment of nodal status is the most appropriate for use in the stage
classification. METHODS: Retrospective survival analyses were performed in 656
consecutive patients with advanced gastric carcinoma who underwent D2
lymphadenectomy and for whom histopathologic data of more than 20 lymph nodes
were available. RESULTS: Although all three systems served well to classify the
patients into distinct groups in terms of survival curves, stratification by the
number of metastatic nodes was vulnerable to stage migration because of
differences in the number of lymph nodes harvested. Such stage migration was not
evident for the other two parameters. CONCLUSIONS: Lymph node metastatic rate can
be recommended as an internationally applicable parameter for lymph node
involvement of gastric carcinoma.
PMID- 9762887
TI - Expression of insulin-like growth factor receptor, IGF-1, and IGF-2 in primary
and metastatic osteosarcoma.
AB - BACKGROUND AND OBJECTIVES: We have previously shown that insulin-like growth
factor (IGF)-responsive murine sarcomas demonstrate inhibition of local and
metastatic disease growth when implanted in an IGF-deficient host animal. In this
experiment, we tested whether IGF receptor (IGF-R) and ligands were expressed in
human primary and metastatic osteosarcomas. METHODS: Fifty-two specimens of human
osteosarcoma tumor from 48 patients were assayed for IGF-R, IGF-1, and IGF-2
using reverse transcriptase polymerase chain reaction. RESULTS: Twenty-one of 46
tumors analyzed had levels of expression of IGF-R greater than or equal to the
positive control cell line. Twenty-seven of 44 expressed levels of IGF-1 greater
than or equal to the positive control, as did 21 of 38 cases assayed for IGF-2.
No differences were found between 40 primary tumor samples and 12 metastatic
lesions in mean levels of IGF-R, IGF-1, or IGF-2. There was a moderately strong
correlation between expression of IGF-R and IGF-1, suggesting that autocrine
stimulation may be an important mechanism for stimulation of osteosarcoma
proliferation. CONCLUSIONS: A significant proportion of osteosarcoma tumors
express IGF-R and ligands. Higher levels of expression were not correlated with
metastatic lesions.
PMID- 9762888
TI - Evaluation of argyrophilic nucleolar organizer region and proliferating cell
nuclear antigen in colorectal cancer.
AB - BACKGROUND AND OBJECTIVES: Information on cellular proliferation is gaining
importance for predicting prognosis in several cancers. To clarify the
clinicopathological significance of argyrophilic nucleolar organizer region
(AgNOR), proliferating cell nuclear antigen (PCNA), and DNA ploidy pattern, we
studied their correlations with clinicopathological factors in colorectal cancer.
METHODS: Fifty-two patients with colorectal cancer were examined by AgNOR
staining, immunohistochemical study of PCNA expression, and DNA flow cytometry.
RESULTS: The AgNOR score and the PCNA labeling rate (PCNA LR) were significantly
higher in patients with deep invasion (P = 0.0072, P = 0.0355), liver metastasis
(P = 0.0022, P = 0.0001), and Dukes D classification (P = 0.0002, P = 0.0001)
than in patients without these factors. In patients with high AgNOR score (>3.83)
or with high PCNA LR (>48.8), prognosis was significantly worse (P = 0.0002, P =
0.0123) than in those with low AgNOR score (<3.83) or in those with low PCNA LR
(<48.8), respectively. No significant association was observed between AgNOR
score and PCNA LR. Combined analysis revealed that the survival curve for
patients with high AgNOR score and high PCNA LR was significantly lower (P =
0.0156) than that for patients with high AgNOR score and low PCNA LR. There was
no significant correlation between DNA ploidy pattern and clinicopathological
findings. CONCLUSIONS: PCNA LR and AgNOR score were correlated not only with
local progression but also with metastasis. Their determination provided useful
prognostic information, and these parameters are probably independent. Their
simultaneous determination was useful for accurate evaluation of prognosis. The
value of DNA ploidy pattern was uncertain.
PMID- 9762889
TI - Colorectal sarcoma: analysis of failure patterns.
AB - BACKGROUND AND OBJECTIVES: Colorectal sarcomas (CRS) are rare and their treatment
remains controversial, especially for those located in the rectum. The aim of
this paper is to evaluate our experience, with special emphasis on the failure
pattern after surgical therapy alone or combined with postoperative radiotherapy.
MATERIALS AND METHODS: The medical records and histological slides of 13 CRS
patients treated between 1986 and 1996 were reviewed retrospectively. RESULTS:
The patients included eight males and five females, with a median age of 54
years; nine of their primary tumors were located in the rectum, and four in the
colon. The histologies were leiomyosarcoma in nine cases and malignant fibrous
histiocytoma in four cases. Surgical treatment consisted of anatomical colectomy
(four); local excision (three); abdominoperineal resection (APR)(two); low
anterior resection (LAR)(two); LAR en bloc with the prostate (one), and total
pelvic exenteration (one). One operative death occurred. The median size of the
tumors was 8 cm (range, 5-40). The tumors were graded as low, three, and high,
ten. The median follow-up was 24 months. Eight patients in the overall group
developed recurrences as follows: local, three; local and distant, three, and
distant, two. Five out of nine patients with rectal sarcoma received adjuvant
postoperative radiotherapy (PRT). Local recurrence occurred in 20% (1/5) of those
who received PRT, and in 100% (3/3) of those who did not. The overall 5-year
survival was 40%, and the 5-year survival for patients with low-grade tumors was
66%, as compared with 22% for those with high-grade tumors. CONCLUSIONS: The
patterns of failure in CRS are combined in both local and distant sites. However,
our results suggest that in rectal sarcoma, the use of surgery + PRT may reduce
the local recurrence rate; in selected patients, it may allow for anal sphincter
preservation.
PMID- 9762890
TI - Therapeutic significance of palliative operations for gastric cancer for survival
and quality of life.
AB - BACKGROUND AND OBJECTIVES: There have been few reports on the objective
assessment of quality of life (QOL) in patients with gastric cancer following
palliative operations. The benefit of a palliative operation for survival and QOL
of patients with gastric cancer is not clear. METHODS: Survival and hospital-free
survival (HFS), which is considered to be one objective indicator of QOL, were
studied in 95 patients undergoing palliative operations for gastric cancer.
Univariate and multivariate analyses were used to determine the clinicopathologic
factors potentially related to survival of patients. RESULTS: In univariate
analysis, palliative gastrectomy and absence of peritoneal dissemination were
significantly correlated with better survival. The significance of palliative
gastrectomy for survival was, therefore, evaluated for various degrees of
peritoneal dissemination: P0 no dissemination; P1, metastasis to the adjacent
peritoneum; P2, a few scattered metastases to the distant peritoneum; and P3,
numerous metastases. Survival and achievement of HFS for 3 months or longer were
higher following palliative gastrectomy than gastrojejunostomy. Among
gastrectomies, however, total gastrectomy performed in patients with P2 or P3
showed a poorer outcome for survival and HFS than total gastrectomy performed
with P0 or P1 and distal gastrectomy. CONCLUSIONS: As a palliative measure,
gastrojejunostomy and total gastrectomy performed with P2 or P3 peritoneal
dissemination had no beneficial effect on the prolongation of survival or
improvement of QOL of patients with gastric cancer.
PMID- 9762891
TI - Fluorodeoxyuridine causes bilomas after hepatic cryotherapy.
AB - BACKGROUND AND OBJECTIVES: Hepatic cryotherapy is a method of in situ
cytodestruction used for unresectable liver tumours that can be combined with
regional cytotoxic administration. We have used intra-arterial chemotherapy with
5-fluorouracil (5-FU) after hepatic cryotherapy but changed to 5
fluorodeoxyuridine (FUDR) because of the arterial toxicity of 5-FU. A new
complication was seen. METHODS: A retrospective case note study was performed of
130 patients who had undergone hepatic cryotherapy followed by regional
chemotherapy at our centre. Seven patients received FUDR; 123 received 5-FU.
RESULTS: Biloma at the cryotherapy sites was seen in three patients in the FUDR
group; two other patients in this group had other types of hepatic collection.
Our previous experience with intra-arterial 5-FU in 123 patients after hepatic
cryotherapy showed no evidence of this syndrome. CONCLUSIONS: Intra-arterial FUDR
should not be used after hepatic cryotherapy, at least during the immediate
postoperative period.
PMID- 9762892
TI - Richter hernia of the stomach.
AB - A case report is presented of Richter hernia of the stomach, after en bloc
excision of multiple organs for sarcoma of the left upper quadrant of the
abdomen. To our knowledge this is the first case reported in the literature. The
conditions for the development of this hernia are : (1) the freeing of the
greater curvature of the stomach (following removal of the spleen and tail of the
pancreas); and (2) fascial dehiscence following a left thoracoabdominal incision
involving rib resection.
PMID- 9762893
TI - Surgical management of adrenal metastases from lung cancer.
AB - BACKGROUND AND OBJECTIVES: Adrenal metastases from lung cancer usually indicate
systemic disease and incurability. However, a small subset of patients with
isolated adrenal metastases may achieve long-term survival with aggressive
surgical resection of the adrenal gland. To clarify the role of adrenalectomy for
metastatic lung cancer, we undertook a review of the published literature on this
topic. METHODS: The English-language medical literature was searched for papers
reporting surgical resection of adrenal metastases from lung cancer. Eleven
articles were retrieved and their data pooled for analysis. RESULTS: Sixty
patients (including seven previously reported from our institution) formed the
basis of this collective review. Thirty-two patients pooled from small series and
case reports had a median survival of 24 months, and approximately one-third were
5-year survivors. Twenty-eight patients reported in two large series had a less
favorable survival (approximately 14 months median survival). CONCLUSIONS:
Surgical resection of isolated adrenal metastases from lung cancer appears to
have a modest survival advantage over nonoperative therapy, and it occasionally
results in long-term survival. However, the relatively encouraging survival
results reported in the literature could be related to careful patient selection
for this aggressive therapy, publication bias in favor of positive treatment
outcomes, or a combination of the two. Nevertheless, the results are encouraging
enough to justify further investigation of this aggressive treatment strategy.
Practical guidelines for management are proposed.
PMID- 9762894
TI - Identification of mouse crystallins in 2D protein patterns by sequencing and mass
spectrometry. Application to cataract mutants.
AB - The eye lens proteins of the mouse were separated into 1940 polypeptide spots by
two-dimensional electrophoresis in large gels. All 16 crystallins ubiquitous in
mammals were identified by protein sequencing and mass spectrometry except for
(gamma)-F, which shows an almost identical sequence with (gamma)-E. Two
crystallins, (beta)-A2 and (gamma)-S, were shown for the first time to occur in
the mouse lens. An investigation of the murine cataract mutant Cat2(nop)((gamma)
B gene) demonstrated that a monogenic mutation might affect a broad spectrum of
proteins.
PMID- 9762895
TI - Genomic structure and promoter analysis of the p62 gene encoding a non
proteasomal multiubiquitin chain binding protein.
AB - p62 is a novel immediate early response gene encoding a ubiquitin chain binding
protein. To investigate the mechanism of p62 gene expression, we isolated and
characterized the 20 kb long human p62 gene. The p62 gene contains seven introns
and eight exons. The splice sites conformed to the GT/AG rule, except introns 6
and 7 which used the unusual GC dinucleotides. The p62 promoter is TATA-less, and
357 nucleotides of the 5'-flanking region contain basic machineries for
transcription. A reporter gene linked to 1800 nucleotides of the 5'-flanking
region was rapidly activated by various extracellular signals. The presence of a
CpG island as well as multiple binding sites for SP-1, AP-1, NF-kappaB, and Ets-1
family in the promoter region supports the regulated activation of the p62 gene.
PMID- 9762896
TI - Expression of alternatively spliced human latent transforming growth factor beta
binding protein-1.
AB - Latent transforming growth factor beta binding protein-1 (LTBP1) is important in
regulating the localisation and activation of transforming growth factor
beta(TGFbeta). Three forms of LTBP1 mRNA have previously been described, LTBP1L,
LTBP1S and LTBPdelta53. Here, we have analysed the LTBP1 coding sequence and
identified two other spliced forms, LTBP1delta55 and LTBP1delta41. LTBP1delta55
is a short form of LTBPIL which lacks 55 amino acids including two consensus N
glycosylation sites and LTBP1delta41 is a form of LTBP1 which lacks the 12th EGF
like repeat. Furthermore, sequencing of genomic clones showed that splicing to
generate LTBP1L occurs using an intra-exonic 3' splice acceptor site in the first
coding exon of LTBP1S and that LTBP1delta55 arises from the alternative use of an
exonic 3' splice acceptor site at the end of the following intron. LTBP1delta41
arises from skipping the exon which encodes the 12th EGF-like repeat.
LTBP1delta55 and LTBP1delta41 mRNA are expressed in a wide variety of human
tissues but the proportions of each splice form vary in the tissues.
PMID- 9762897
TI - Isolation and sequence of cDNA encoding the motilin precursor from monkey
intestine. Demonstration of the motilin precursor in the monkey brain.
AB - The motilin precursor cDNA has been isolated and sequenced from a cDNA library
prepared from monkey small intestine. The sequence indicates a 345 bp open
reading frame, a 63 bp 5' untranslated region and a 154 bp 3' untranslated
region. The sequence encodes a 115 amino acid motilin precursor composed of a 25
amino acid signal peptide, the 22 amino acid motilin peptide and a 68 amino acid
motilin associated peptide (MAP). Compared with the human motilin precursor cDNA,
there are two amino acid substitutions in the signal peptide, one in motilin and
four in the MAP. The presence of the motilin precursor in hypothalamus,
hippocampus and cerebellum was demonstrated by RT-PCR.
PMID- 9762898
TI - Age-related increased susceptibility of high-density lipoproteins (HDL) to in
vitro oxidation induced by gamma-radiolysis of water.
AB - In the present study, we investigated the age-related susceptibility of high
density lipoproteins (HDL) to oxidation. HDL were obtained from healthy,
normolipidemic young, middle-aged and elderly subjects. Oxidation of HDL was
induced in vitro by oxygen free radicals generated by water gamma-radiolysis, and
followed by the decrease of endogenous vitamin E and the formation of conjugated
dienes and thiobarbituric acid-reactive substances, as well as the alterations of
apolipoproteins A-I/A-II. The resistance of HDL to oxidation, evaluated by the
length of the lag phase, decreased with aging. This increased oxidizability of
HDL with aging could have a dramatic impact on the development of atherosclerosis
in the elderly population.
PMID- 9762899
TI - Novel defensin subfamily from spinach (Spinacia oleracea).
AB - Antimicrobial peptides (So-D1-7) were isolated from a crude cell wall preparation
from spinach leaves (Spinacia oleracea cv. Matador) and, judged from their amino
acid sequences, six of them (So-D2-7) represented a novel structural subfamily of
plant defensins (group IV). Group-IV defensins were also functionally distinct
from those of groups I-III. They were active at concentrations < 20 microM
against Gram-positive (Clavibacter michiganensis) and Gram-negative (Ralstonia
solanacearum) bacterial pathogens, as well as against fungi, such as Fusarium
culmorum, F. solani, Bipolaris maydis, and Colletotrichum lagenarium. Fungal
inhibition occurred without hyphal branching. Group-IV defensins were
preferentially distributed in the epidermal cell layer of leaves and in the
subepidermal region of stems.
PMID- 9762900
TI - The mystery of the trichothecene 3-O-acetyltransferase gene. Analysis of the
region around Tri101 and characterization of its homologue from Fusarium
sporotrichioides.
AB - The trichothecene 3-O-acetyltransferase gene, Tri101, plays a pivotal role for
the well-being of the type B trichothecene producer Fusarium graminearum. We have
analyzed the cosmids containing Tri101 and found that this resistance gene is not
in the biosynthetic gene cluster reported so far. It was located between the UTP
ammonia ligase gene and the phosphate permease gene which are not related to
trichothecene biosynthesis. These two 'house-keeping' genes were also linked in
Fusarium species that do not produce trichothecenes. The result suggests that the
isolated occurrence of Tri101 is attributed to horizontal gene transfer and not
to the reciprocal translocation of the chromosome containing the gene cluster.
Interestingly, 3-O-acetylation was not always a primary self-defensive strategy
for all the t-type trichothecene producers; i.e. the type A trichothecene
producer Fusarium sporotrichioides did not acetylate T-2 toxin in vivo although
the fungus possessed a functional 3-O-acetyltransferase gene. Thus Tri101 appears
to be a defense option which the producers have independently acquired in
addition to their original resistance mechanisms.
PMID- 9762901
TI - Inhibition of glycosaminoglycan modification of perlecan domain I by site
directed mutagenesis changes protease sensitivity and laminin-1 binding activity.
AB - Glycosaminoglycan attachment to perlecan domain I (173 residues) was completely
prevented by site-directed mutagenesis of Ser-65, Ser-71 and Ser-76 as shown by
recombinant production in mammalian cells. This did not interfere with the proper
folding of the domain's SEA module but enhanced its sensitivity to neutral
proteases. Lack of substitution also abolished binding to the two major heparin
binding sites of laminin-1.
PMID- 9762902
TI - Isolation, characterization and synthesis of a novel paradaxin isoform.
AB - We report the isolation of a novel pardaxin isoform from the toxic secretion of
the Red Sea Moses sole (Pardachirus marmoratus). Mass spectrometrical analysis of
the newly purified peptide revealed a different primary structure compared to the
previously known pardaxin isoforms. Sequence analysis disclosed an aspartic acid
residue instead of glycine at position 31 of the new isoform. According to the
novel sequence, a synthetic Asp-31-peptide was compared with the native compound
as well as with synthetic Gly-31-pardaxin. The isolated Asp-31-pardaxin isoform
and its synthetic analog exhibited identical elution properties during reverse
phase HPLC, as well as similar dose-dependent lytic effects on human erythrocytes
at a concentration of 10(-6) to 10(-5)M. The hemolytic activity of Asp-31
pardaxins was lower than that of Gly-31-pardaxin and no synergistic effect
between these peptides was found. The additional negative charge introduced by
Asp-31 is likely to affect the selectivity of pardaxin pores towards a variety of
ions.
PMID- 9762903
TI - ATP-dependent copper transport by the Menkes protein in membrane vesicles
isolated from cultured Chinese hamster ovary cells.
AB - The Menkes (MNK) protein is a vital component of copper homeostasis in mammalian
cells. In this paper we provide the first biochemical evidence that the MNK
protein functions as a copper-translocating P-type ATPase in mammalian cells. The
enzyme activity in membrane vesicles prepared from Chinese hamster ovary cells
overexpressing MNK was ATP-dependent, correlated with the amount of MNK and
followed Michaelis-Menten kinetics with respect to copper. The copper transport
was observed only under reducing conditions suggesting MNK transports Cu(I). This
study opens the way to detailed structure-function studies and assessment of
functional MNK derived from patients with Menkes disease.
PMID- 9762904
TI - Mitochondrial Hsp70 cannot replace BiP in driving protein translocation into the
yeast endoplasmic reticulum.
AB - To determine whether mitochondrial hsp70 (mHsp70) could substitute for the
endoplasmic retuculum (ER) Hsp70 (BiP) during protein translocation, we assembled
ER-derived reconstituted proteoliposomes supplemented with either protein. We
found that only BiP restored translocation in kar2 mutant vesicles and stimulated
translocation approximately 3-fold in wild type proteoliposomes. mHsp70
associated poorly with both a BiP binding (DnaJ) domain of Sec63p and an ER
precursor, and its ATPase activity was poorly enhanced upon incubation with the
DnaJ domain. In contrast, BiP bound to the Sec63p-DnaJ domain in an ATP-dependent
manner and its ATPase activity was stimulated significantly by this polypeptide.
We conclude that mHsp70 is unable to support protein translocation into the ER
because it fails to associate productively with Sec63p and a precursor.
PMID- 9762905
TI - Effect of CRF and related peptides on calcium signaling in human and rodent
melanoma cells.
AB - Corticotropin releasing factor (CRF) induces a rapid, within seconds, and dose
dependent increase in the intracellular Ca2+ in both human and hamster melanoma
cells. This effect is inhibited by depletion of extracellular calcium using 3 mM
EGTA and is attenuated by the CRF receptor antagonist, alpha-helical-CRF(9-41).
Other peptides of the CRF superfamily, sauvagine and urocortin, also induce
increases in cytoplasmic calcium concentration but at higher concentrations than
CRF. We conclude that malignant melanocytes express CRF receptors, which are
coupled to activation of plasma membrane calcium channels.
PMID- 9762906
TI - Structure of the human transcription factor TFIIF revealed by limited proteolysis
with trypsin.
AB - In this study, the human general transcription factor IIF (TFIIF), a heteromeric
complex of RAP74 and RAP30 subunits, was subjected to limited proteolysis with
trypsin. The central region of RAP74 was demonstrated to be highly sensitive to
trypsin while both the N- and C-terminal regions contained trypsin-resistant
structures. In contrast, RAP30 digestion occurred after proteolysis of RAP74. The
digestion pattern of RAP74 recruited into the preinitiation complex showed no
marked difference from that of IIF, while RAP30 in the complex was protected from
trypsin. These results indicate that RAP74 apparently contains three structural
domains, the central one of which is externally surfaced and unstructured, but
RAP30 is internally wrapped by RAP74. Furthermore, the accessibility of the
central region of RAP74 is unaltered in the minimal preinitiation complex, while
RAP30 is involved in promoter recognition through its DNA binding activity.
PMID- 9762907
TI - Okadaic acid-induced apoptosis of HL60 leukemia cells is preceded by
destabilization of bcl-2 mRNA and downregulation of bcl-2 protein.
AB - We have studied the actions of the protein phosphatase inhibitor okadaic acid
(OA) on the expression of bcl-2 in HL60 human leukemia cells. OA induced
downregulation of bcl-2 mRNA and protein prior to the induction of apoptosis.
Downregulation of bcl-2 mRNA levels did not result from actions of OA on the bcl
2 upstream negative response element. Nuclear run-off analyses confirmed that OA
did not affect bcl-2 gene transcription. However, OA caused a rapid increase in
the rate of degradation of bcl-2 mRNA. Therefore, OA induces down-regulation of
bcl-2 expression via destabilization of its transcript. The constitutive action
of an OA-sensitive protein phosphatase may therefore maintain HL60 cell survival
by blocking bcl-2 mRNA degradation.
PMID- 9762908
TI - A second isoform of gonadotropin-releasing hormone is present in the brain of
human and rodents.
AB - Gonadotropin-releasing hormone-I (GnRH-I), present in the mammalian hypothalamus,
regulates reproduction. In this study we demonstrate, for the first time, that an
additional isoform of GnRH, [His5, Trp7, Tyr8] GnRH-I (GnRH-II) is present in the
brain of the mouse, rat and human. Human and rat brain extracts contain two
isoforms of GnRH, GnRH-I and GnRH-II, which exhibited identical chromatographic
properties to the respective synthetic peptides, in high performance liquid
chromatography. Using immunohistochemical techniques we have found that GnRH-II
is present in neuronal cells that are localized mainly in the periaqueductal area
as well as in the oculomotor and red nuclei of the midbrain. It is of interest to
note that in the hypogonadal mouse, although the GnRH-I gene is deleted, GnRH-II
is present. Substantial concentrations of GnRH-II are also present in the
hypothalamus and stored in the human pituitary stalk or in the mouse median
eminence. By using reverse transcription (RT)-PCR we have also found that while
GnRH-II is not expressed in the cerebellum, it is expressed in all three
structures of the brain stem: midbrain, pons and medulla oblongata.
PMID- 9762909
TI - cDNA cloning of Brassica napus malonyl-CoA:ACP transacylase (MCAT) (fab D) and
complementation of an E. coli MCAT mutant.
AB - The GenBank database was searched using the E. coli malonyl CoA:ACP transacylase
(MCAT) sequence, for plant protein/cDNA sequences corresponding to MCAT, a
component of plant fatty acid synthetase (FAS), for which the plant cDNA has not
been isolated. A 272-bp Zea mays EST sequence (GenBank accession number:
AA030706) was identified which has strong homology to the E. coli MCAT. A PCR
derived cDNA probe from Zea mays was used to screen a Brassica napus (rape) cDNA
library. This resulted in the isolation of a 1200-bp cDNA clone which encodes an
open reading frame corresponding to a protein of 351 amino acids. The protein
shows 47% homology to the E. coli MCAT amino acid sequence in the coding region
for the mature protein. Expression of a plasmid (pMCATrap2) containing the plant
cDNA sequence in Fab D89, an E. coli mutant, in MCAT activity restores growth
demonstrating functional complementation and direct function of the cloned cDNA.
This is the first functional evidence supporting the identification of a plant
cDNA for MCAT.
PMID- 9762910
TI - Growth factor protection against cytokine-induced apoptosis in neonatal rat
islets of Langerhans: role of Fas.
AB - Treatment of neonatal rat islets of Langerhans with combined cytokines
(interleukin-1beta 10(-10) M, tumour necrosis factor-alpha 10(-10) M, interferon
gamma 5 U/ml) led to extensive cell death, which was potentiated by Fas
activation with the anti-Fas cytolytic antibody JO2. Pre-treatment with insulin
(25 ng/ml) or insulin-like growth factor-1 (10(-8)M) gave only partial protection
against cell killing, but prevented the Fas-mediated component. In the absence of
cytokine treatment, Fas-mediated killing was not observed.
PMID- 9762912
TI - Fatty acids as natural uncouplers preventing generation of O2.- and H2O2 by
mitochondria in the resting state.
AB - Both natural (laurate) and artificial (m-chlorocarbonylcyanide phenylhydrazone;
CCCP) uncouplers strongly inhibit O2.- and H2O2 formation by rat heart
mitochondria oxidizing succinate. Carboxyatractylate, an ATP/ADP antiporter
inhibitor, abolishes the laurate inhibition, the CCCP inhibition being
unaffected. Atractylate partially releases the inhibition by laurate and
decelerates the releasing effect of carboxyatractylate. GDP is much less
effective than carboxyatractylate in releasing the laurate inhibition of reactive
oxygen species (ROS) formation. Micromolar laurate concentrations arresting the
ROS formation cause strong inhibition of reverse electron transfer from succinate
to NAD+, whereas State 4 respiration and the transmembrane electric potential
difference (delta psi) level are affected only slightly. It is suggested that (i)
free fatty acids operate as natural 'mild uncouplers' preventing the
transmembrane electrochemical H+ potential difference (delta muH+) from being
above a threshold critical for ROS formation by complex I and, to a lesser
degree, by complex III of the respiratory chain, and (ii) it is the ATP/ADP
antiporter, rather than uncoupling protein 2, that is mainly involved in this
antioxidant mechanism of heart muscle mitochondria.
PMID- 9762911
TI - The effects of SNAP/SNARE complexes on the ATPase of NSF.
AB - The ATPase of the N-ethylmaleimide sensitive factor (NSF) appears to be central
to the events that culminate in vesicle-target membrane fusion. Complexes
containing different combinations of NSF, alpha-SNAP, Vamp-2 (synaptobrevin 2),
syntaxin 1, and SNAP-25 were reconstituted and then tested for their effect on
the ATPase of NSF. While NSF interacts with all alpha-SNAP-containing complexes,
only the alpha-SNAP/t-SNARE complex significantly stimulated ATPase activity.
This stimulation was dependent on increasing SNAP/t-SNARE complex and was
saturable. The apparent stimulation of ATPase activity is due to a 10-fold
increase in initial hydrolysis rate. Complex containing both v- and t-SNAREs
bound significantly more alpha-SNAP but did not stimulate the ATPase of NSF.
PMID- 9762914
TI - Intestinal lactase-phlorizin hydrolase (LPH): the two catalytic sites; the role
of the pancreas in pro-LPH maturation.
AB - Brush border lactase-phlorizin hydrolase carries two catalytic sites. In the
human enzyme lactase comprises Glu-1749, phlorizin hydrolase Glu-1273. The
proteolytic processing of pro-lactase-phlorizin hydrolase by (rat) enterocytes
stops two amino acid residues short of the N-terminus of 'mature' final, brush
border lactase-phlorizin hydrolase. Only these two amino acid residues are
removed by luminal pancreatic protease(s), probably trypsin.
PMID- 9762913
TI - Enthalpy of captopril-angiotensin I-converting enzyme binding.
AB - High-sensitivity titration calorimetry is used to measure changes in enthalpy,
heat capacity and protonation for the binding of captopril to the angiotensin I
converting enzyme (ACE; EC 3.4.15.1). The affinity of ACE to captopril is high
and changes slightly with the pH, because the number of protons linked to binding
is low. The determination of the enthalpy change at different pH values suggests
that the protonated group in the captopril-ACE complex exhibits a heat
protonation of approximately -30 kJ/mol. This value agrees with the protonation
of an imidazole group. The residues which may become protonated in the complex
could be two histidines existing in two active sites, which are joined to the
amino acids coordinated to Zn2+. Calorimetric measurements indicate that
captopril binds to two sites in the monomer of ACE, this binding being
enthalpically unfavorable and being dominated by a large positive entropy change.
Thus, binding is favored by both electrostatic and hydrophobic interactions. The
temperature dependence of the free energy of binding deltaG degrees is weak
because of the enthalpy-entropy compensation caused by a large heat capacity
change, deltaCp =-4.3+/-0.1 kJ/K/mol of monomeric ACE. The strong favorable
binding entropy and the negative deltaCp indicate both a large contribution to
binding due to hydrophobic effects, which seem to originate from dehydration of
the ligand-protein interface, and slight conformational changes in the vicinity
of the active sites.
PMID- 9762915
TI - Effects of a time-varying strong magnetic field on transient increase in
cytosolic free Ca2+ induced by bradykinin in cultured bovine adrenal chromaffin
cells.
AB - We tested the effects of exposure to a time-varying magnetic field changing
between 0.07 and 1.7 T at an interval of 3 s on transient increase in
intracellular Ca2+ stimulated by bradykinin in bovine adrenal chromaffin cells.
Addition of bradykinin induced the increase in intracellular Ca2+ within a few
minutes. The exposure to the magnetic field perfectly suppressed the increase in
intracellular Ca2+ in Ca2+-free medium. The inhibition occurred for 15 min when
the maximum magnetic flux density was more than 1.4 T. These results suggest that
the exposure inhibits Ca2+ release from intracellular Ca2+ stores.
PMID- 9762916
TI - Activation of caspase-3-like protease by digitonin-treated lysosomes.
AB - Apoptosis, a naturally occurring programmed cell death or cell 'suicide', has
been paid much attention as one of the critical mechanisms for morphogenesis and
tissue remodeling. Activation of cysteine aspartases (caspases) is one of the
critical steps leading to apoptosis. Although a mitochondria-mediated pathway has
been postulated to be one of the activation mechanism of caspase-3, another
subcellular compartment might be involved in the activation of the enzyme. The
present study shows that the supernatant fraction of digitonin-treated lysosomes
strongly activates Ac-DEVD-CHO inhibitable caspase-3-like protease. Activation of
caspase-3-like protease by digitonin-treated lysosomal fractions was specifically
suppressed by leupeptin and E-64, inhibitors of cysteine protease. These results
indicate that leakage of lysosomal cysteine protease(s) into the cytosolic
compartment might be involved in the activation of caspase-3-like protease.
PMID- 9762917
TI - NSF is required for the brefeldin A-promoted disassembly of the Golgi apparatus.
AB - N-Ethylmaleimide-sensitive factor (NSF) is required for multiple pathways of
vesicle-mediated protein transport. Microinjection of a monoclonal anti-NSF
antibody almost completely blocked brefeldin A-promoted Golgi disassembly without
affecting the rapid release of beta-COP, a subunit of the Golgi coat proteins
(COPI), from the Golgi apparatus. Similar results were obtained using a dominant
negative NSF which is known to compete with endogenous NSF. The present results
suggest that an NSF-mediated step is present in the brefeldin A-promoted
disassembly of the Golgi apparatus.
PMID- 9762918
TI - The Pzh1 protein phosphatase and the Spm1 protein kinase are involved in the
regulation of the plasma membrane H+-ATPase in fission yeast.
AB - We have previously shown that the mutation of the Schizosaccharomyces pombe PPZ
like protein phosphatase encoded by the gene pzh1+ results in increased tolerance
to sodium and in hypersensitivity to potassium ions. A similar phenotype has also
been reported for deletants in the spm1/pmk1 gene, encoding a mitogen-activated
protein (MAP) kinase. We have found that the sodium tolerance phenotype of pzh1
deletants is stronger than that of spm1 mutants, and both effects are additive.
Therefore, most probably both gene products mediate different pathways on sodium
tolerance. In our hands, mutation of the kinase does not alter the tolerance to
potassium, but it yields cells more tolerant to magnesium ions. While in budding
yeast the mutations are synthetically lethal, fission yeast cells lacking both
the phosphatase and the kinase genes are viable. Interestingly, their ability to
export H+ to the medium is greatly impaired (although not that of pzh1 or spm1
single mutants). We have observed that, although the amount of the H+-ATPase in
the plasma membrane is not altered, the activity of the enzyme is lower than
normal and cannot be induced by glucose. These observations suggest that the
activity of the H+-ATPase in fission yeast might be regulated by phospho
dephosphorylation mechanisms that might involve the pzh1+ and spm1+ gene
products.
PMID- 9762919
TI - Heterologous expression of human H1 histones in yeast.
AB - The complete set of seven human H1 histone subtype genes was heterologously
expressed in yeast. Since Saccharomyces cerevisiae lacks standard histone H1 we
could isolate each recombinantly expressed human H1 subtype in pure form without
contamination by endogenous H I histones. For isolation of the H1 histones in
this expression system no tagging was needed and the isoforms could be extracted
with the authentic primary structure by a single extraction step with 5%(0.74 M)
perchloric acid. The isolated H1 histone proteins were used to assign the subtype
genes to the corresponding protein spots or peaks after two-dimensional gel
electrophoresis and capillary zone electrophoresis, respectively. This allowed us
to correlate transcriptional data with protein data, which was barely possible
until now.
PMID- 9762920
TI - Two distinct classes of rat intestinal mucosal enzymes incorporating putrescine
into protein.
AB - Tissue-transglutaminase (t-TGase) is a family of calcium-dependent enzymes. A
Ca2+-independent soluble enzyme, in addition to t-TGase, capable of incorporating
polyamines into proteins was demonstrated in rat intestinal mucosa. The Ca2+
independent enzyme was stimulated 2- to 5-fold by Fe2+ and Co2+ ions but
inhibited by Cu2+ and Zn2+ ions. The Ca2+-stimulated t-TGase activity was
inhibited by divalent ions in the following order: Zn2+, Fe2+ >Co2+ > Cu2+. The
opposite effects of EGTA, Fe2+ and Co2+ on these two enzyme activities indicate
that they are two distinct classes of enzymes. Competition studies demonstrated
differential preferences of the two enzymes for substrates. The Ca2+-dependent
enzyme preferred putrescine, monodansylcadaverine > cadaverine, spermidine,
spermine > 1,10-diaminodecane > triethylbutylamine. On the other hand, the Ca2+
independent enzyme preferred putrescine > cadaverine > spermine, I,10
diaminodecane > spermidine > monodansylcadaverine > triethylbutylamine. Further
studies with divalent ions excluded the possible association of this novel Ca2+
independent enzyme with diamine oxidase. Finally, the Ca2+-independent enzyme had
a higher affinity for putrescine (Km = 0.02 mM) than did Ca2+-dependent t-TGase
(0.2 mM). As judged by gel filtration on HiPrep Sephacryl 200 column, the Ca2+
independent enzyme had a molecular weight of approximately 48 kDa, the intestinal
Ca2+-dependent t-TGase was about 188 kDa while that of testicular t-TGase was
about 96 kDa. In conclusion, the Ca2+-independent enzyme is stimulated by cobalt
or ferric ions, and selectively incorporates aliphatic diamines or polyamines
with symmetric amino groups. The observed Ca2+-independent enzyme activity is not
related to diamine oxidase or its products. With a 10 times greater affinity for
putrescine, the calcium-independent, 48-kDa intestinal enzyme may mediate
polyamine function better than calcium dependent, 188-kDa intestinal tissue
transglutaminase in the intestinal mucosa.
PMID- 9762921
TI - NMDA-receptor antagonist requirements in conantokin-G.
AB - A series of variants of the neuroactive 17-residue gamma-carboxyglutamate-(Gla)
containing polypeptide, conantokin-G (con-G), were synthesized with the intention
of determining those features that were important for its N-methyl-D-aspartate
(NMDA) receptor-targeted antagonist activity and for adoption of its divalent
cation-dependent alpha-helical conformation. Employing the binding of
[3H]dizolcipine (MK-801) as an assay for open receptor ion channels in rat brain
membranes, which displays inhibition by con-G (IC50 = 0.48 microM), it was found
that replacement by an Ala residue of Gla4 led to complete inactivation of the
peptide, whereas a similar replacement of Gla3 resulted in a 20-fold decreased
potency. Ala substitutions for Gla10 and Gla14 did not substantially affect
[3H]MK-801 binding. This same substitution at Gla7 appeared to slightly enhance
binding. Ala replacements of non-Gla residues demonstrated that four of them,
viz. Glu2, Leu5, Gln9, and Ile12, possessed at least 200-fold decreases in
inhibitory potency, whereas similar replacements at Gly1, Leu11, and Arg13
resulted in peptides with 8- to 12-fold increases in the IC50 values. The
remaining amino acid residues tested in the single Ala replacement series showed
no significant changes in the inhibitory characteristics of wild-type con-G.
Additional studies with carboxyl-terminal truncated peptides revealed that the
carboxyl-terminal 4 amino acids were unimportant for this activity. There was no
strict correlation of inhibition of [3H]MK-801 binding with the ability of these
peptides to form cation-dependent alpha-helices. Peptides with notably low alpha
helical content in the presence of these cations were lacking at least one, or
both, of Gla10 and Gla14. Con-G[Gla3,4,7,10,14E] and con-G[Gla7,10,14E] were the
only peptides that remained in a completely random conformation upon metal ion
addition.
PMID- 9762922
TI - Cloning, expression, and localization of a novel gamma-adaptin-like molecule.
AB - We describe the cloning, expression, and localization of gamma2-adaptin, a novel
isoform of gamma-adaptin. The predicted human and mouse gamma2-adaptin proteins
are approximately 90 kDa and 64.4% and 61.7%) identical to gamma-adaptin,
respectively. gamma2-Adaptin was localized to the Golgi, its localization
distinct from gamma-adaptin. The membrane association of gamma- and gamma2
adaptin could further be distinguished by differential sensitivity to the fungal
metabolite brefeldin A, gamma2-adaptin binding being insensitive to drug
treatment. Together, these results suggest that gamma2-adaptin plays a role in
membrane transport distinct from that played by gamma-adaptin.
PMID- 9762923
TI - Membrane potential generation coupled to oxidation of external NADH in liver
mitochondria.
AB - Oxidation of added NADH by rat liver mitochondria has been studied. It is found
that exogenous NADH, when oxidized by rat liver mitochondria in sucrose hypotonic
medium supplemented with Mg2+ and EGTA, generates a membrane potential (delta
psi) even in the absence of added cytochrome c. ADP and phosphate decrease delta
psi, the effect being reversed by oligomycin. Rotenone and myxothiazol do not
inhibit delta psi generated by oxidation of exogenous NADH. Added cytochrome c
increases the rate of the exogenous NADH oxidation and coupled delta psi
formation. In sucrose isotonic medium, or in hypotonic medium without Mg2+,
exogenous NADH fails to stimulate respiration and to form a membrane potential.
In the presence of Mg2+, exogenous NADH appears to be effective in delta psi
generation in isotonic sucrose medium if mitochondria were treated with
digitonin. In isotonic KCl without Mg2+, oxidation of exogenous NADH is coupled
to the delta psi formation and MgCl2 addition before mitochondria prevents this
effect. In hypotonic (but not in isotonic) sucrose medium, Mg2+ makes a portion
of the cytochrome c pool reducible by exogenous NADH or ascorbate. It is assumed
that (i) hypotonic treatment or digitonin causes disruption of the outer
mitochondrial membrane, and, as a consequence, desorption of the membrane-bound
cytochrome c in a Mg2+-dependent fashion; (ii) incubation in isotonic KCI without
Mg2+ results in swelling of mitochondrial matrix, disruption of the outer
membrane and cytochrome c desorption whereas Mg2+ lowers the K+ permeability of
the inner membrane and, hence, prevents swelling; (iii) desorbed cytochrome c is
reduced by added NADH via NADH-cytochrome b5 reductase and cytochrome b5 or by
ascorbate and is oxidized by cytochrome oxidase. The role of desorbed cytochrome
c in oxidation of superoxide and cytoplasmic NADH as well as possible relations
of these events to apoptosis are discussed.
PMID- 9762924
TI - Identification of a dynein molecular motor component in Torpedo electroplax;
binding and phosphorylation of Tctex-1 by Fyn.
AB - The microtubule protein Tctex-1 was cloned from Torpedo electroplax, a
biochemical model of the neuromuscular junction, using the unique domain of Fyn
in the yeast two hybrid system. Binding of Tctex-1 and Fyn also occurred in
vitro. Torpedo Tctex-1 was contained within the molecular motor protein dynein. A
Src class kinase was also complexed with dynein. Tctex-1 was enriched in electric
organ vs. skeletal muscle, was present in the postsynaptic membrane, and
coprecipitated with the acetylcholine receptor. The sequence of Tctex-1 contained
a tyrosine phosphorylation motif and Tctex-1 could be phosphorylated by Fyn in
vitro and in vivo. These data demonstrated that Tctex-1-containing dynein is a
cytoskeletal element at the acetylcholine receptor-enriched postsynaptic membrane
and suggested that Tctex-1 may be a substrate for Fyn.
PMID- 9762925
TI - Cancer epidemiology 50 years later.
PMID- 9762926
TI - Can cancer risks be altered by changing nutritional traditions?
PMID- 9762927
TI - Cancer surveillance in the U.S.: can we have a national system?
AB - Cancer-related services are consuming ever-increasing health resources; along
with this trend, health care costs are rising. As health care planners,
researchers, and policymakers formulate strategies to meet this challenge, they
are looking to cancer registries and the health information system built around
them as collectors of the most extensive information regarding cancer treatment
in the U.S. Currently, there are multiple programs collecting and reporting data
regarding cancer incidence, morbidity, mortality, and survival. This report
profiles cancer surveillance efforts in the U.S. and describes the National
Coordinating Council for Cancer Surveillance, which was organized in 1995 to
facilitate a collaborative approach among the organizations involved.
PMID- 9762929
TI - Immunohistochemical evaluation of thymidylate synthase in gastric carcinoma using
a new polyclonal antibody: the clinical role of thymidylate synthase as a
prognostic indicator and its therapeutic usefulness.
AB - BACKGROUND: Before this study was conducted, the clinical and therapeutic
significance of immunohistochemical evaluation of thymidylate synthase (TS) in
patients with gastric carcinoma had not yet been clarified. METHODS: TS was
immunohistochemically evaluated in 134 gastric carcinomas using anti-TS antibody.
TS expression, 11 clinicopathologic variables, and survival were studied, and the
correlations among them were investigated. RESULTS: The groups with high and low
TS levels consisted of 56 and 78 patients, respectively. Granular cytoplasmic
staining patterns of tumor cells were produced by immunohistochemical staining of
the gastric carcinoma tissues. The grade of TS staining was significantly
correlated with three clinicopathologic variables: depth of invasion, peritoneal
metastasis, and stage of the carcinoma (P < 0.05). A univariate analysis revealed
that the 5-year survival was significantly better for the low TS group than for
the high TS group (P < 0.05): 65.2% for the low TS group and 43.2% for the high
TS group. The group with high grade TS staining who received chemotherapy because
of the advanced stage of their disease had worse prognoses even if they received
adjuvant chemotherapy. A multivariate analysis revealed that four variables
(peritoneal metastasis, lymphatic invasion, liver metastasis, and TS staining
grade) independently contributed to survival (P < 0.05). The hazard ratio for the
group with low grade TS staining was 0.464 compared with the group with high
grade staining. CONCLUSIONS: The immunohistochemical evaluation of TS using this
anti-TS antibody may be clinically and therapeutically useful in determining the
prognosis of gastric carcinoma patients.
PMID- 9762928
TI - Salivary gland malignant myoepithelioma: a clinicopathologic and
immunohistochemical study of ten cases.
AB - BACKGROUND: Malignant myoepithelioma (MME) of the salivary gland, also known as
myoepithelial carcinoma, is rare and its biologic behavior has not been clarified
fully. METHODS: Ten cases of MME were analyzed for their clinicopathologic
features and immunohistochemical characteristics, focusing on prognostic factors
and tumor differentiation. In addition, six cases of benign myoepithelioma (BME)
also were examined for comparison. RESULTS: The ten patients with MME (3 men and
7 women) ranged in age from 48-81 years (mean, 61.9 years). Seven cases of MME
arose in the parotid salivary gland, two in the submandibular salivary gland, and
one in minor salivary glands of the soft palate. In the current series, the
incidence of MME was 0.45% among 1945 cases of major salivary gland tumors. Seven
cases of MME developed from a benign preexisting tumor (six in pleomorphic
adenoma and one in BME). Four of nine patients with MME died of the disease and
two patients developed a recurrence. It was shown that MMEs were comprised of one
cell type or a combination of two cell populations; these included, in order of
incidence, epithelioid, spindle, and plasmacytoid cells. Patients with MME with
marked cellular pleomorphism and perineural invasion had a poor prognosis.
Immunohistochemically, putative myoepithelial markers such as muscle actins,
cytokeratin 14, vimentin, and calponin, and S-100 protein were expressed highly
in MME. High and low molecular weight cytokeratins and epithelial membrane
antigen also frequently were positive in MME. p53 expression was observed in five
MME cases, four of which either recurred or were fatal. Cellular proliferative
activity assessed by mitotic count and the Ki-67 labeling index was significantly
higher in MME cases than in BME cases. In limited cases, such cellular
proliferative activity was shown to have prognostic value. Ultrastructurally, the
tumor cells displayed certain myoepithelial characteristics. CONCLUSIONS: MME is
a rare salivary gland tumor showing clinicopathologic diversity and presenting
with various stages of myoepithelial differentiation. Histologic aggressiveness,
marked cellular pleomorphism, p53 expression, and high cell proliferative
activity were found to be correlated with a poor clinical outcome.
PMID- 9762930
TI - Multifocal occurrence of gastric carcinoma in patients with a family history of
gastric carcinoma.
AB - BACKGROUND: Smoking and alcoholic beverage drinking habits as well as a family
history of cancer are well known risk factors for the multifocal occurrence of
squamous cell carcinoma of the esophagus and the head and neck region. However,
the role of these risk factors in multiple gastric carcinoma remains to be
clarified. The purpose of this study was to examine the risk factors for multiple
gastric carcinoma. METHODS: The smoking and drinking habits as well as the family
history of 157 patients with synchronous multiple gastric carcinoma and 157
patients with solitary gastric carcinoma who were similar with regard to gender,
age, stage of the tumor, and year of admission were investigated. The risk of a
multiple occurrence of gastric carcinoma also was elevated using the odds ratio
(OR). RESULTS: The ORs of a multifocal occurrence of gastric carcinoma in
patients who currently smoked and drank alcoholic beverages were 1.1 and 0.8,
respectively, although the ORs were not related to the quantity of smoking or
drinking. In patients with a close relative with gastric carcinoma the OR was 2.1
(95% confidence interval [CI], 1.3-3.7). In those patients with > or =2 close
relatives with gastric carcinoma, the OR increased to 5.1 (95% CI, 1.2-21.1).
Conversely, no significant elevation in the ORs was recognized regarding a family
history of other cancers. CONCLUSIONS: In this study, a family history of gastric
carcinoma was found to be clearly associated with the multifocal occurrence of
gastric carcinoma; however, no significant correlation between the multifocal
occurrence of gastric carcinoma in these patients and their smoking and drinking
habits was recognized.
PMID- 9762931
TI - A clinicopathologic study of mucinous gastric carcinoma including multivariate
analysis.
AB - BACKGROUND: Mucinous gastric carcinoma (MGC) is a rare subtype of gastric
adenocarcinoma, and its clinical and pathologic features are still controversial.
To clarify the significance of this subtype of carcinoma, the authors conducted a
case-control study to investigate the clinicopathologic characteristics of MGC
and determine whether this mucin-producing histologic type is associated with a
worse prognosis than other gastric carcinomas. METHODS: Twenty-two cases of MGC
and 46 patients with nonmucinous gastric carcinoma (NGC) were included. Patients
were evaluated on the basis of age, gender, tumor size, location, depth of tumor
invasion, histologic differentiation, lymph node involvement, organ metastasis,
stage at presentation, surgical curability, adjuvant chemotherapy and radiation
therapy. To determine whether the MGC itself was an independent prognostic
factor, a multivariate analysis was performed with the Cox proportional hazards
model. RESULTS: The MGC patients were found to have larger tumors (P < 0.001),
tumors more often located in the upper stomach (P < 0.05), more serosal invasion
(P < 0.05), more lymph node involvement (P < 0.05), greater frequency of advanced
stage disease (P < 0.01), and lower 5-year survival rates (P < 0.05) than NGC
patients. There was no significant correlation between the subtypes of
differentiation of MGC and other data, including the prognosis. Multivariate
analysis showed that clinically important predictive factors were serosal
invasion and disease stage at diagnosis. The mucinous histologic type itself was
not an independent factor for poor prognosis. CONCLUSIONS: The overall survival
rate for patients with MGC was worse than that for patients with NGC. The poor
prognosis was correlated with more advanced stage at diagnosis and more frequent
serosal invasion, not with the mucinous histologic type.
PMID- 9762932
TI - Rectal epithelial proliferation in persons with or without a history of adenoma
and its association with diet and lifestyle habits.
AB - BACKGROUND: Rectal epithelial proliferation (REP) measurements are used as a
biomarker of risk for colorectal neoplasia and response to chemoprevention. The
authors evaluated REP in screenees with and without a history of adenoma and its
association with demographic and adenoma characteristics, diet, and other
lifestyle habits. METHODS: Long term lifestyle habits were evaluated and
proliferation assessed by in vitro bromodeoxyuridine labeling of rectal biopsies
in 223 screenees, 132 of whom had adenomas removed > 3 years previously. Analyses
included the total population, screenees with a previous history of adenomas and
adenoma free screenees separately, and a subgroup of 55 matched adenoma cases and
controls. RESULTS: Crypt proliferation measurements were not elevated in
screenees with a history of adenomas compared with adenoma free screenees (mean
total labeling index [LI] of 4.8% and 4.9%, respectively). This was confirmed by
the case-control analysis, in which the LI of the most superficial crypt
compartment was lower in the adenoma cases (P=0.05). Moreover, their total LI
correlated negatively with the number of adenomas removed previously (P < 0.01).
Proliferation was more frequent in the most superficial crypt compartments of
female adenoma free screenees than in female screenees with a history of adenomas
(P=0.02), and in men age > 65 years compared with younger men (P=0.06). In the
total population, negative Spearman rank correlations were found between total LI
and long term dietary intake of calcium (correlation coefficient [r]=-0.15;
P=0.02), LI of the two most superficial crypt compartments and intake of fiber
(r=-0.18; P=0.01), water (r=-0.12; P=0.08), and carbohydrates (not significant).
A positive correlation was found between LI of the most superficial crypt
compartment and cigarette smoking (r=0.4; P=0.02). CONCLUSIONS: REP measurements
did not discriminate between screenees with a history of adenomas and adenoma
free screenees. Long-term lifestyle habits, gender, and age were associated with
REP levels and need to be considered when evaluating human intervention studies.
PMID- 9762933
TI - Adenocarcinoma of the pancreas: detection of occult metastases in regional lymph
nodes by a polymerase chain reaction-based assay.
AB - BACKGROUND: Stage I (T1-2NOM0) adenocarcinoma of the pancreas is associated with
a 5-year survival rate of 15-25%. Despite apparently curative resection and
pathologic staging indicating localized disease, these cancers recur. The authors
hypothesized that there exists microscopic regional disease that is not detected
by surgical exploration or routine histopathology. METHODS: Because 90-95% of
pancreatic cancers exhibit codon 12 K-ras mutations, the authors examined
regional lymph nodes for mutated K-ras as a marker of metastasis. DNA was
extracted from paraffin embedded archival specimens (primary tumors and
histologically negative lymph nodes) of patients with Stage I pancreatic
adenocarcinoma. The target region of K-ras was amplified by polymerase chain
reaction (PCR) and tested for codon 12 mutation by BstN1 restriction digestion
(restriction fragment length polymorphism [RFLP]) that recognized normal but not
mutated sequences. Cell lines that harbored normal or mutated K-ras and resected
jejunum or gallbladder were used as controls. The regional lymph nodes of 22
patients whose tumors harbored mutated K-ras were tested. RESULTS: Dilution
experiments with normal and mutant control cell line DNA demonstrated an assay
sensitivity for mutated K-ras of 0.1%. Mutated K-ras was found in at least 1
regional lymph node in 16 (73%) of 22 patients with pathologic Stage I pancreatic
adenocarcinoma, which suggested metastases not detected by routine
histopathology. DNA sequence analysis was performed in four patients and
confirmed identical point mutations in the primary tumor and accompanying
PCR/RFLP positive lymph nodes. CONCLUSIONS: Pathologic examination of regional
lymph nodes in pancreatic adenocarcinoma specimens fails to detect metastases in
many patients. Lymph node micrometastasis is one reason for the poor survival
rates observed among patients with Stage I cancers. PCR/RFLP may have a role in
staging early pancreatic cancers.
PMID- 9762934
TI - Bombesin/gastrin-releasing peptide antagonists RC-3095 and RC-3940-II inhibit
tumor growth and decrease the levels and mRNA expression of epidermal growth
factor receptors in H-69 small cell lung carcinoma.
AB - BACKGROUND: Antagonists of bombesin/gastrin-releasing peptide (BN/GRP) have been
developed to block the autocrine stimulatory effect of BN/GRP on tumors such as
small cell lung carcinoma (SCLC). Although several studies have addressed the
intracellular events that follow the formation of the receptor-ligand complex,
the mechanism of action of BN/GRP antagonists remains unclear. METHODS: In this
study the authors investigated the effect of synthetic BN/GRP antagonists RC-3095
and RC-3940-II on tumor growth and the expression of epidermal growth factor
receptors (EGF-R) in H-69 SCLC. Athymic nude mice xenografted with H-69 SCLC were
treated subcutaneously for 5 weeks with RC-3095 and RC-3940-II at the dose of 10
microg/animal/day. RESULTS: RC-3095 decreased tumor volume by approximately 50%
(P < 0.05) and RC-3940-II by 70-60% (P < 0.01). Tumor burden also was
significantly decreased in the groups treated with RC-3095 and RC-3940-II.
Receptor analyses demonstrated high affinity binding sites for BN/GRP and EGF on
the untreated H-69 SCLC tumors. After treatment with RC-3095 and RC-3940-II, the
concentration of receptors for BN/GRP was decreased by 29.0% and 36.5%,
respectively (both, P < 0.01) compared with controls, and EGF-R levels were
reduced by 62.3% and 63.0%, respectively (both, P < 0.01). Reverse transcriptase
polymerase chain reaction and Southern blot analyses revealed that the levels of
mRNA for EGF-R in tumors were lowered by 31% (P < 0.05) and 43% (P < 0.01),
respectively, after treatment with RC-3095 and RC-3940-II. CONCLUSIONS: This
study indicates that the inhibition of growth of H-69 SCLC by BN/GRP antagonists
RC-3095 and RC-3940-II is accompanied by a marked decrease in the levels and mRNA
expression of EGF-R.
PMID- 9762935
TI - Remission induction therapy of untreated acute myeloid leukemia using a non
cytarabine-containing regimen of idarubicin, etoposide, and carboplatin.
AB - BACKGROUND: The safety and efficacy of idarubicin, etoposide, and carboplatin as
remission induction therapy for patients younger than 60 years with untreated
acute myeloid leukemia was studied as an alternative to standard regimens based
on cytarabine plus anthracycline. METHODS: Eligible patients received idarubicin
(36-40 mg/m2), etoposide (500 mg/m2), and carboplatin (1000-1500 mg/m2) over 5
days. Those who achieved complete remission received a single course of
cytarabine 1.5 gm/m2 every 12 hours for a total of 12 doses. D-xylose absorption
was studied as a marker for cytotoxic therapy-induced gut mucosal damage.
Cytogenetic and immunophenotyping studies were performed at the time of diagnosis
and examined for prognostic importance. RESULTS: Remission was achieved in 29
(67%) of 43 patients with a single induction course. The median leukemia free and
overall survival times were 15.4 months (95% CI 6.5-24.2) and 12.5 months (95% CI
5.9-19.1), respectively. Induction mortality was 14%. Karyotype (normal, simple,
or complex vs. very complex) was the strongest predictor of remission (79% vs.
25%, P=0.01), leukemia free survival (odds ratio [OR] 19.3, 95% CI 2.7-138.9),
and overall survival (OR 5.4, 95% CI 2.1-13.9). Dose-limiting gut mucosal
toxicity was greatest during Weeks 2 and 3. Bloodstream infections occurred in
49% of patients at a median of 12 days. Grade 3-4 diarrhea, nausea, stomatitis,
esophagitis/dysphagia, and vomiting developed in 33%, 26%, 23%, 9%, and 2% of
cases, respectively, at a median of 17, 16, 11, 15.5, and 21 days, respectively.
CONCLUSIONS: This regimen was active in adults younger than 60 years with
untreated acute myeloid leukemia and normal, simple, or complex karyotypes.
Remission duration was confounded by karyotype. Mucosal toxicity limited the
tolerability of this regimen. These adverse effects might be overcome by
increasing the intensity of postremission therapy and modifying the dosing
schedule.
PMID- 9762936
TI - Tumor-associated antigen TA-90 immune complex assay predicts subclinical
metastasis and survival for patients with early stage melanoma.
AB - BACKGROUND: TA-90 is a tumor-associated antigen first identified in the urine and
sera of patients with metastatic melanoma. In the early stages of disease, TA-90
is present in circulating immune complexes (ICs) that may be detected with an
antigen specific enzyme-linked immunosorbent assay (ELISA). In this study, the
authors evaluated the efficacy of the TA-90 IC assay in detecting subclinical
metastasis of early stage melanoma and predicting the survival of patients with
this disease. METHODS: Archival sera were collected preoperatively from 114
patients who underwent wide excision with or without regional lymphadenectomy in
the treatment of clinical Stage I melanoma. Sera were analyzed for TA-90 IC in a
blinded fashion, and results were correlated with the patient's clinical course
as determined by database and chart review. Subclinical metastases were
considered present at the time of surgery if the lymphadenectomy specimen was
pathologically positive and/or the patient subsequently developed recurrence.
RESULTS: The TA-90 IC assay predicted subclinical metastasis in 43 of 56 patients
(P < 0.0001), with 14 false-positive and 13 false-negative results. Sensitivity
and specificity for the detection of occult metastasis were 77% and 76%,
respectively. Positive and negative predictive values were 75% and 77%,
respectively. Fifteen of 18 tumor positive regional lymph node basins (83%) and
34 of 46 recurrences (74%) were accurately predicted when considered
independently (P < 0.004). Preoperative TA-90 IC status was also highly
correlated with survival: 5-year overall and disease free survival rates were 63%
and 46%, respectively, for the TA-90 IC positive group, compared with 88% and
82%, respectively, for the TA-90 IC negative group (P=0.0001). A multivariate
analysis with standard prognostic variables identified preoperative TA-90 IC
status as a strong, independent prognostic factor for both overall and disease
free survival. CONCLUSIONS: To the authors' knowledge, TA-90 is the first tumor
marker that accurately predicts subclinical metastatic disease and survival for
patients with early stage melanoma. For this reason, the TA-90 IC assay has the
potential to improve dramatically the prognostic evaluation of patients with this
disease. Its role in postoperative risk stratification and early detection of
recurrence is being evaluated in a prospective study.
PMID- 9762937
TI - Complications of axillary lymph node dissection for carcinoma of the breast: a
report based on a patient survey.
AB - BACKGROUND: Axillary lymph node dissection is commonly performed as part of the
primary management of breast carcinoma. Its value in patient management, however,
has recently been questioned. Few studies exist that document long term
complications. METHODS: Four hundred thirty-two patients with Stage I or II
breast carcinoma who were free of recurrence 2-5 years after surgery were
identified. A cross-sectional survey was conducted to determine the prevalence of
long term symptoms and complications as perceived by the patient, and patient and
treatment factors that may have predicted complications were determined. Three
hundred thirty of the 432 (76%) completed a mailed, self-administered
questionnaire. In addition, the medical records of the 330 patients were
reviewed. Patient and treatment factors were analyzed with logistic regression.
RESULTS: Numbness was reported by 35% of patients at the time of the survey. Pain
was noted in 30%, arm swelling in 15%, and limitation of arm movement in 8%.
Eight percent reported episodes of infection or inflammation at some point since
the diagnosis of breast carcinoma. The majority of symptoms were mild and
interfered minimally with daily activities. Younger age (P=0.001) was associated
with more frequent reporting of pain. Numbness was more common in younger
patients (P=0.004) as well as in those with a history of smoking (P=0.012). There
was a positive association of limitation of arm motion with adjuvant tamoxifen
therapy (P=0.016). Arm swelling was associated with both younger age (P=0.004)
and greater body surface area (P=0.008). Radiation therapy was associated with a
higher frequency of infection or inflammation in the arm and/or breast (P=0.001).
CONCLUSIONS: Mild symptoms, especially pain and numbness, are common 2-5 years
after axillary lymph node dissection. The frequency of inflammation or infection
in patients treated with radiation to the breast or chest wall after an axillary
lymph node dissection may be greater than previously appreciated. Severe
complications or symptoms that have a major impact on daily activities are
uncommon. These findings should help health care providers and their patients
with breast carcinoma weigh the pros and cons of axillary lymph node dissection.
PMID- 9762938
TI - A proposed glossary of terminology related to the surgical treatment of vulvar
carcinoma.
AB - BACKGROUND: The authors' objective was to provide a glossary of terminology
related to the surgical treatment of invasive vulvar carcinoma. There is
currently no consensus in the literature regarding the names of the surgical
procedures used to treat this disease. METHODS: A surgical glossary should be
supported by clear definitions and acceptance of notions related to topographic
anatomy that are specific to the surgical practice. A critical review of the
classic, chiefly used Italian, French, German, and English textbooks of anatomy
revealed some discrepancies and lack of uniformity in descriptions of vulvar and
inguinal fascial structures and lymph nodes, which represent the principal
landmarks of surgical treatment. In the proposed glossary, the descriptions of
these anatomic landmarks integrate classic anatomic knowledge, data from recent
gynecologic studies of inguinal anatomy, and the clinical experiences of the
authors. RESULTS: The glossary is composed of 16 surgical definitions, which are
divided into 3 main sections of terminology describing the surgical treatment of
the: 1) vulva, 2) inguinal lymph nodes, and 3) pelvic lymph nodes. The
fundamental objective behind the glossary is to describe the area and the depth
of the surgical procedure. Three determinants of the area (local, partial, and
total) and three determinants of the depth of surgery (superficial, simple, and
deep) were used to arrive at the fully articulated definitions in the glossary.
CONCLUSIONS: The authors are aware that the proposed glossary should not be
considered a definitive one; however, it could serve as a good basis for further
debate. The terms employed in the glossary are accompanied by anatomic and
descriptive references to help avoid confusion and promote better understanding
among gynecologic oncologists who are involved in the treatment of vulvar
carcinoma.
PMID- 9762939
TI - Expression of p150 in cervical neoplasia and its potential value in predicting
survival.
AB - BACKGROUND: A recently cloned novel p150 protein was found to be overexpressed in
human breast carcinoma. To the authors' knowledge, no data on p150 expression in
any other human tumors have been published previously. METHODS: To investigate
whether the expression of p150 correlated with the clinicopathologic stages of
cervical neoplasms or the prognoses of patients with these neoplasms, the authors
conducted an immunohistochemical study of archival formalin fixed, paraffin
embedded specimens. Seventy-two precancerous lesions (CIN), 75 clinical Stage IB
invasive squamous carcinomas, and 20 samples of normal squamous epithelia were
included. In addition to p150, the Ki-67 labeling index was assessed as a
proliferation parameter. The presence of human papillomavirus was analyzed by in
situ DNA hybridization. RESULTS: A significant association of p150 with the grade
of atypia in cervical neoplasms was demonstrated. The highest expression of p150
was observed in low grade CIN, with subsequently decreasing expression in high
grade CIN and invasive carcinoma. For patients with invasive carcinoma, p150 was
significantly correlated with clinical outcome. Patients with high expression of
p150 had a better prognosis than those with low p150. Those with regional lymph
node metastasis and significant p150 expression had longer relapse free survival
than those with insignificant p150 expression. Women whose carcinomas
demonstrated vascular space invasion or high microvessel density survived longer
when p150 was clearly expressed. p150 behaves as a potential tumor marker during
early cervical carcinoma development and is later turned off as cells proceed to
more advanced stages of their malignant phenotypes. CONCLUSIONS: p150 is a
molecular parameter that might become useful in predicting disease progression
and determining the prognoses of patients with invasive cervical carcinoma.
PMID- 9762940
TI - Angiogenesis in adenocarcinoma of the uterine cervix.
AB - BACKGROUND: Angiogenesis is essential for tumor growth, progression, and
metastases. Microvessel density (MVD), a measure of tumor angiogenesis, has been
found to have prognostic significance in many tumor types for predicting
metastasis and survival. METHODS: Between 1979-1989, 56 cases of FIGO Clinical
Stage I and II adenocarcinoma of the uterine cervix treated by hysterectomy were
reviewed histologically. All hysterectomy specimens were stained
immunohistologically for factor VIII-related antigen. MVD was counted in a x200
field (0.785 mm2 per field) in the most active area of neovascularization.
Results were expressed as the highest number of microvessels identified within
any single x200 field. MVD and several other prognostic parameters were examined
for correlation with progression free survival (PFS) and overall survival (OS) by
a multivariate analysis according to the Cox proportional hazards model. RESULTS:
In early adenocarcinoma of the uterine cervix, MVD was increased significantly in
invasive areas compared with adjacent nonneoplastic areas (median: 62.5 [range,
30-105] vs. median: 36.5 [range, 23-47]; P=0.0003). MVD also was significantly
correlated with ascites cytology (P=0.0377). There was no correlation between
microvessel count and lymph node status, depth of invasion, disease stage, lymph
vascular space invasion, grade, or parametrial involvement. Patients with high
MVD (> or=75) had significantly worse PFS and OS than those with low MVD (< 75)
(log rank test, P=0.0180 and 0.0199, respectively). Multivariate analysis showed
that MVD correlated significantly and independently with PFS and OS. CONCLUSIONS:
In adenocarcinoma of the cervix, MVD is an independent prognostic factor for PFS
and OS.
PMID- 9762941
TI - Endocrine tumors of the cervix: morphologic assessment, expression of human
papillomavirus, and evaluation for loss of heterozygosity on 1p,3p, 11q, and 17p.
AB - BACKGROUND: Cervical endocrine tumors are rare lesions, with a varied diagnostic
nomenclature. A recent consensus meeting proposed a standardized terminology.
This study evaluated: 1) applicability of histopathologic guidelines; 2) evidence
of loss of heterozygosity (LOH) at selected sites; and 3) the presence of human
papillomavirus (HPV) detected by nonisotopic in situ hybridization (ISH).
METHODS: Thirty-eight cases (patient age range, 19-88 years; mean, 48 years) were
retrieved. Outcome data were available for 32 patients. Classification was based
on architectural and cytologic features. Tissue was available from 15 cases for
LOH analysis with D3S1234(3p14), D3S1289(3p21), THRB(3p24), TP53(17p13),
D1S468(1p36), and INT-2(11q13). In ten cases, tissue was analyzed by nonisotopic
ISH with HPV probes for types 6/11, 16/18, and 31/33. RESULTS: Tumors were
divided into four groups: small cell carcinoma (SCC) (n=25); large cell
neuroendocrine carcinoma (LCNC) (n=5); SCC with focal LCNC differentiation (n=3),
and carcinoid tumor (n=5). Tumors defined as exclusively or predominantly SCC had
a particularly poor prognosis, with 20 patients dead of disease (<6 years after
diagnosis) and 6 alive with disease (after <3 years of follow-up). LOH at various
3p loci (3p14, 3p21, and 3p24) was observed in eight cases. One patient
demonstrated LOH on 17p(TP53). Eight of ten cases assessed by ISH showed nuclear
staining using a combined HPV-16/18 probe. CONCLUSIONS: Cervical endocrine tumors
are highly aggressive and can be subdivided into definable categories. LOH at 3p
loci is a frequent finding, as is nuclear staining with a combined HPV-16/18
probe. LOH at 17p(TP53 locus) appears to be relatively uncommon, suggesting that
p53 mutations may not be developmentally significant.
PMID- 9762942
TI - Expression of ras, c-myc, and p53 proteins in cervical intraepithelial neoplasia.
AB - BACKGROUND: The development of cervical carcinoma is influenced by multiple
factors, including the presence of certain high risk types of human
papillomavirus. The purpose of the current study was to investigate possible
cooperating genetic changes by examining the expression of p53, p62 myc, and p21
ras in cervical biopsy specimens. METHODS: Three hundred and ninety-five cervical
biopsy specimens representing normal through high grade cervical intraepithelial
neoplasia (CIN) were screened by immunohistochemistry for expression of p53,
p62myc, and p21ras. RESULTS: Neither the proportion of tissues staining positive
for a given protein nor the staining patterns within the epithelial layers
differed significantly among normal or CIN biopsy samples. However, grade
specific nuclear staining of p21ras was found in the cells of 10 lesions that
were classified as CIN I by histology. CONCLUSIONS: These results established the
normal distribution and expression patterns of p53, p62myc, and p21ras within 395
cervical biopsy samples representing normal through CIN III histology. The
expression of these proteins (e.g., staining intensity and layer of epithelium
staining positive) is similar in normal tissues and those demonstrating all
grades of CIN.
PMID- 9762943
TI - Postchemotherapy residual masses in germ cell tumor patients: content, clinical
features, and prognosis. Medical Research Council Testicular Tumour Working
Party.
AB - BACKGROUND: In a retrospective study that included a detailed histopathologic
review, the clinicopathologic features of patients with germ cell tumors (GCT)
and resectable residual masses after chemotherapy were assessed. METHODS:
Histologic material from 153 patients was available for review. Recorded details
included primary histologic diagnosis, location, size and number of metastases,
marker levels before and after chemotherapy, and completeness of surgical
excision. A median of seven histologic sections per resection were reviewed by
two pathologists independently (and together when disagreement occurred). In each
case, details were recorded regarding fibrosis, necrosis, hemorrhage, embryonal
carcinoma (undifferentiated teratoma), yolk sac tumor, choriocarcinoma
(trophoblastic tumor), differentiated teratoma (mature and immature), dysplasia
in somatic tissues, and non- germ cell tumor (GCT) malignancies. The percentage
of the sample that each of these components comprised was also estimated.
RESULTS: The median postchemotherapy follow-up time was 7 years, and 38 of 153
patients (25%) experienced disease progression. In a multivariate analysis,
incomplete resection of all residual masses (in 38 patients) and the presence of
malignant elements (in 23 patients) were independent risk factors for
progression. In the subset of patients in whom all masses were completely
resected, the presence of embryonal carcinoma (undifferentiated teratoma) was the
single most significant risk factor for progression. Seven percent of patients
had this factor, which was associated with a 2-year progression free survival
rate of 12.5%, compared with 88.0% where this component was absent. CONCLUSIONS:
Progression free survival can be predicted well by the completeness of excision
of residual masses and the presence of malignant germ cell elements. The latter
confers a relatively poor prognosis even if all of these elements are completely
resected.
PMID- 9762944
TI - Ovarian transposition by laparoscopy before radiotherapy in the treatment of
Hodgkin's disease.
AB - BACKGROUND: The use of inverted Y irradiation in the treatment of Hodgkin's
disease with pelvic lymph node involvement can cause iatrogenic early menopause
in young women as a result of ovarian exposure to radiation. Ovarian
transposition protects the ovaries by removing them from the irradiation field.
This surgical procedure, initially performed by laparotomy, can now be done by
laparoscopy. METHODS: During the period July 1994 to April 1996, laparoscopic
ovarian transposition was performed on 4 young women with Hodgkin's disease 1
week before inverted Y radiotherapy. The surgical procedure, complications,
length of hospitalization, and hormonal, clinical, and biologic results were
evaluated. RESULTS: The mean duration of hospitalization was 4 days, and there
were no postoperative complications. Iatrogenic menopause did not occur in any of
the patients during the mean follow-up period of 20.75 months (range, 6-35
months; median, 20 months). CONCLUSIONS: Laparoscopy offers many advantages over
laparotomy for ovarian transposition. This procedure, which can be performed
without opening the abdominal wall, is highly efficient, requires only a short
period of hospitalization, and leads to few postoperative complications.
Laparoscopy is an attractive alternative to laparotomy for ovarian transposition
in young women with advanced Hodgkin's disease who require pelvic radiotherapy.
PMID- 9762945
TI - Progress in improving diet to reduce cancer risk.
AB - BACKGROUND: In an effort to decrease cancer risk among the population, national
health objectives for the year 2000 included recommendations to decrease intake
of dietary fat and alcohol and increase intake of fruits, vegetables, and grains.
The purpose of this article is to assess trends in the intake of these dietary
components relative to the national health objectives. METHODS: National food
supply data and food consumption survey data were reviewed for their
appropriateness for monitoring intake trends. Recent data from both sources are
described and interpreted. RESULTS: Americans have made modest but important
improvements in their diets in recent years and may meet the "Healthy People
2000" dietary objectives aimed at decreasing cancer risk. Intake of fruits,
vegetables, and grains are higher, and those of fat and alcohol are lower than
they were at the beginning of the decade. These trends are consistent with recent
improvements in mortality rates for those cancer sites with the strongest
associations with diet: the colon/rectum, prostate, and breast. CONCLUSIONS:
Although the average intake of fruits, vegetables, and grain products is higher,
it should be noted that the objective represents the minimum recommendations.
Within each of these major food groups, further improvements can be made. In
addition, special efforts should be made to guide children toward improvements in
their diets and to monitor the diets of children and other subgroups.
PMID- 9762946
TI - Oral glutamine reduces the duration and severity of stomatitis after cytotoxic
cancer chemotherapy.
AB - BACKGROUND: Mouth sores and/or difficulty swallowing are common and painful
consequences of cytotoxic chemotherapy for cancer. In previous studies oral
glutamine was found to protect animals from the effects of whole abdominal
radiation and methotrexate-induced enteritis. Glutamine also was found to reduce
oral mucositis in a nonrandomized pilot study in humans. Therefore, the authors
attempted to determine the efficacy of oral glutamine in a randomized, double
blind, crossover trial in cancer patients receiving chemotherapy. METHODS: Twenty
four patients (16 children and 8 adults) received glutamine or placebo (glycine)
suspension (2 g amino acid/M2/dose twice daily) to swish and swallow on days of
chemotherapy administration and for at least 14 additional days. Patients
completed a calendar indicating days of mouth pain associated with each
chemotherapy course and the effect of mouth pain on oral intake. RESULTS: Paired
data indicated significant amelioration of stomatitis associated with glutamine
administration after chemotherapy. The duration of mouth pain was 4.5 days less
in chemotherapy courses in which glutamine supplementation was compared with
placebo (Wilcoxon's signed rank test, P=0.0005). The severity of oral pain also
was reduced significantly when glutamine was provided with chemotherapy (the
amount of days mucositis restricted oral intake to soft foods [> or =Grade 2;
Modified Eastern Cooperative Oncology Group grading system] was 4 days less with
glutamine compared with placebo; Wilcoxon's signed rank test, P=0.002).
CONCLUSIONS: Low dose oral glutamine supplementation during and after
chemotherapy significantly reduced both the duration and severity of chemotherapy
associated stomatitis. Oral glutamine appears to be a simple and useful measure
to increase the comfort of many patients at high risk of developing mouth sores
as a consequence of intensive cancer chemotherapy.
PMID- 9762947
TI - Epidemiology of osteosarcoma and Ewing's sarcoma in childhood: a study of 305
cases by the Children's Cancer Group.
AB - BACKGROUND: The Children's Cancer Group conducted a case-control study to
determine the role of a broad range of environmental and familial factors in the
etiology of Ewing's sarcoma and osteosarcoma in children. These factors included
radiation exposure and, for children with osteosarcoma, parental exposure to
beryllium. METHODS: The parents of 152 children with osteosarcoma and 153
children with Ewing's sarcoma were interviewed by telephone. Controls were
obtained by random digit dialing and were matched to cases by age and race.
RESULTS: Female osteosarcoma patients had earlier onset of breast development
(age 11.4 vs. 11.8 years, P=0.03) and menarche (age 12.1 vs. 12.5 years, P=0.002)
but no significant differences in growth, whereas male osteosarcoma patients were
similar in age at the onset of secondary sexual characteristics but reported
significantly less weight gain during their growth spurt (6.6 vs. 11.7 kg,
P=0.003). For children with Ewing's sarcoma, the growth spurt began earlier (age
12.1 vs. 12.7 years, P=0.12) and resulted in less weight and height gain (5.2 vs.
9.7 kg, P=0.002, and 10.2 vs. 12.7 cm, P=0.02, respectively) for males, but no
differences were observed among females. For factors not related to growth and
development (including a wide range of occupational, medical, and household
exposures), there was little evidence of an etiologic role with respect to either
tumor type. CONCLUSIONS: Differences between cases and controls with respect to
growth and development showed no consistent pattern. This study did not identify
any important risk factors for either type of childhood bone tumor.
PMID- 9762948
TI - A Phase I study of granulocyte-macrophage-colony stimulating factor/interleukin-3
fusion protein (PIXY321) following ifosfamide, carboplatin, and etoposide therapy
for children with recurrent or refractory solid tumors: a report of the
Children's Cancer Group.
AB - BACKGROUND: This Phase I trial was developed to determine the safety, biologic
activity, and effects on hematopoietic recovery of PIXY321 following ifosfamide,
carboplatin, and etoposide chemotherapy for children with recurrent or refractory
solid tumors. METHODS: Children (age < 22 years at diagnosis) received ifosfamide
1800 mg/m2/day x 5 days, carboplatin 400 mg/m2/day x 2 days, and etoposide 100
mg/m2/day x 5 days, followed by daily subcutaneous administration of PIXY321.
Dose-limiting toxicity was defined as Grade IV toxicity related to PIXY321.
Pharmacokinetic and endogenous cytokine production studies were conducted during
Course 1, and peripheral blood (PB) progenitor cell and receptor expression
studies were conducted during Course 1 when the white blood cell count recovered
to > or=1000/mm3. RESULTS: Twenty-four children received ifosfamide, carboplatin,
and etoposide chemotherapy plus PIXY321, the latter at doses of 500 /g/m2/day
(n=3), 750 microg/m2/day (n=6), 1000 microg/m2/day (n=9), or 500 microg/m2/twice
a day (n=6). PIXY321 was well tolerated, with only 1 dose-limiting toxicity
(chills, occurring at a dose of 750 microg/m2/day). The maximum tolerated dose
was not reached in this study. The median days to absolute neutrophil count
recovery (> or =1000/mm3) and platelet recovery (>100,000/mm3) during Course 1
following PIXY321 (1000 microg/ m2/day) were 22 days (range, 5-33 days) and 20
days (range, 5-31 days), respectively. There was a 2500, 5000, 3000, and 390%
increase in PB granulocyte-macrophage colony-forming units, erythrocyte blast
forming units, granulocyte erythrocyte macrophage and megakaryocyte colony
forming units, and CD34+ cells, respectively. CONCLUSIONS: In summary, this
pediatric Phase I trial demonstrated that PIXY321 was well tolerated by children
and resulted in platelet recovery a median of 20 days after ICE chemotherapy and
an increase in the number of PB progenitor cells above baseline. However, based
on recent negative results with PIXY321 in randomized Phase II/III trials
involving adult subjects, PIXY321 is not currently available for future trials
involving children.
PMID- 9762949
TI - Prenatal exposure to metronidazole and risk of childhood cancer: a retrospective
cohort study of children younger than 5 years.
AB - BACKGROUND: To evaluate the role of in utero exposure to metronidazole (a
carcinogen in some animal models) and the risk of subsequent cancer, the authors
conducted a retrospective cohort study of childhood cancer. METHODS: The cohort
included 328,846 children younger than 5 years born to women enrolled in
Tennessee Medicaid at any time between the last menstrual period (LMP) and the
date of delivery. The cohort was identified by linking files of Tennessee
Medicaid mothers ages 15-44 years and children and the children's birth and death
certificates for the period January 1, 1975 through December 31, 1992. Exposure
data were obtained from Medicaid pharmacy records and exposure was defined as
filling a metronidazole prescription that had at least a day's supply between the
30 days prior to the LMP and the date of delivery. Study cases were cohort
children diagnosed with a first primary cancer before age 5 years, identified by
linking the cohort with a statewide childhood cancer database for the study
period. RESULTS: Cohort members contributed 1,172,696 person-years of follow-up
for analysis, with children exposed (8.1%) and not exposed (91.9%) in utero to
metronidazole contributing 79,716 and 1,092,980 person-years, respectively. Of
952 children younger than 5 years in the statewide cancer database, 175 met study
eligibility criteria. Of these, 42 had leukemia, 30 had central nervous system
(CNS) tumors, 28 had neuroblastoma, and 75 had other cancers. Using Poisson
regression modeling, children exposed to metronidazole in utero had no
significant increase in adjusted relative risk (RR) for all cancers (RR: 0.81;
95% confidence interval [95% CI], 0.41-1.59), leukemia (no exposed case), CNS
tumors (RR: 1.23; 95% CI, 0.29-5.21), neuroblastomas (RR: 2.60; 95% CI, 0.89
7.59), and other cancers (RR: 0.57; 95% CI, 0.18-1.82). CONCLUSIONS: The authors
conclude that although there was no increase in risk for all cancers associated
with in utero exposure to metronidazole, the observed increased risk for
neuroblastomas, although not significant, requires further evaluation.
PMID- 9762950
TI - Detection of chromogranin A mRNA in small cell lung carcinoma using a new, highly
sensitive in situ hybridization method with a non-radioisotope oligonucleotide
probe.
PMID- 9762951
TI - The amnestic prodrome of Alzheimer's disease.
PMID- 9762952
TI - The perception of phantom limbs. The D. O. Hebb lecture.
AB - Almost everyone who has a limb amputated will experience a phantom limb--the
vivid impression that the limb is not only still present, but in some cases,
painful. There is now a wealth of empirical evidence demonstrating changes in
cortical topography in primates following deafferentation or amputation, and this
review will attempt to relate these in a systematic way to the clinical
phenomenology of phantom limbs. With the advent of non-invasive imaging
techniques such as MEG (magnetoencephalogram) and functional MRI, topographical
reorganization can also be demonstrated in humans, so that it is now possible to
track perceptual changes and changes in cortical topography in individual
patients. We suggest, therefore, that these patients provide a valuable
opportunity not only for exploring neural plasticity in the adult human brain but
also for understanding the relationship between the activity of sensory neurons
and conscious experience. We conclude with a theory of phantom limbs, some
striking demonstrations of phantoms induced in normal subjects, and some remarks
about the relevance of these phenomena to the question of how the brain
constructs a 'body image.'
PMID- 9762953
TI - Presymptomatic cognitive deficits in individuals at risk of familial Alzheimer's
disease. A longitudinal prospective study.
AB - A longitudinal study of asymptomatic individuals at risk of autosomal dominant
familial Alzheimer's disease was performed to assess the earliest clinical and
neuropsychological features of the disease. Over a 6-year period, 63 subjects
underwent serial assessments. During the study, 10 subjects developed symptoms of
episodic memory loss and subsequently progressed to fulfil criteria for possible
or probable Alzheimer's disease. The mean time (+/-SD) from first assessment to
the appearance of symptoms was 2.6+/-1.4 years. The subjects who remained well
were similar to those who became clinically affected in terms of age, family
history and initial Mini-Mental State Examination. Individuals who later became
clinically affected already had significantly lower verbal memory (P=0.003) and
performance IQ (P=0.030) scores at their first assessment, when they were
ostensibly unaffected. Subsequent assessments showed progressive decline in
multiple cognitive domains. Blinded assessment of serial imaging revealed the
appearance of diffuse cerebral and medial temporal lobe atrophy in subjects only
once they were clinically affected. These findings imply that in familial
Alzheimer's disease cognitive decline predates symptoms by several years and that
verbal memory deficits precede more widespread deterioration. This may have
implications for the detection and treatment of Alzheimer's disease at an early
stage.
PMID- 9762954
TI - Competition between past and present. Assessment and interpretation of verbal
perseverations.
AB - Perseveration consists of the inappropriate repetition of a preceding behaviour
when a new adapted response is expected. We have developed statistical tools that
make it possible to reveal such perseverations, assess their significance and
study their finer characteristics, such as their temporal course and impaired
processing level. This approach is illustrated and evaluated through analyses of
naming errors produced by three patients with impairments affecting different
stages of the processing chain leading from visual perception to speech
production. These examples of perseverations include the intrusion not only of
whole words (patient R.A.V.) but also of isolated phonemes (patient D.U.M.) or of
visual features (patient Y.M.) from previous trials. In all cases, the
probability that an error is a perseveration from a previous trial is an
exponentially decreasing function of the lag between the two trials considered.
This suggests that perseverations reflect a decaying internal variable, such as
an internal level of activation of previous utterances. Based on these empirical
results, we put forward a tentative mechanism for the generation of
perseverations: whenever a given processing level is deprived of its normal
input, persistent activity inherited from previous trials is no longer overcome
by current input, and is revealed in the form of perseverations.
PMID- 9762955
TI - Quantitative MRI in patients with idiopathic generalized epilepsy. Evidence of
widespread cerebral structural changes.
AB - In patients with idiopathic generalized epilepsy (IGE), visual inspection of
routine MRI is normal. However, pathological studies have shown microdysgenesis
in grey and white matter in a large percentage of autopsies from cases of IGE.
Recently, widespread structural changes not evident on visual inspection of high
resolution MRI have been shown using quantitative MRI in patients with apparently
focal cerebral dysgenesis. We sought to determine whether similar quantitative
changes might be present in patients with IGE, reflecting possible underlying
structural abnormalities. Twenty patients with juvenile myoclonic epilepsy, 10
patients each with childhood absence epilepsy and juvenile absence epilepsy, five
patients with tonic-clonic seizures on awakening and 30 control subjects had T1
weighted volume acquisition MRI scans on a 1.5T GE scanner. The cerebral
hemispheres were segmented semi-automatically, allowing the comparison of
normalized cortical and subcortical matter volumes between groups, and
investigation of the regional distribution of cortical and subcortical matter in
individual subjects. Patients with IGE had significantly larger cortical grey
matter volumes than control subjects. Significant abnormalities of the regional
distribution of cerebral grey and subcortical matter were found in eight out of
20 patients with juvenile myoclonic epilepsy, one out of 10 patients with
childhood absence epilepsy, four out of 10 patients with juvenile absence
epilepsy and two out of five patients with tonic-clonic seizures on awakening,
but in none of the 30 control subjects. Using MRI-segmentation, we identified
widespread cerebral structural changes in patients with various IGE syndromes.
Quantitative MRI supports the existence of structural abnormalities in patients
with IGE.
PMID- 9762956
TI - Three cortical stages of colour processing in the human brain.
AB - We used the technique of functional magnetic resonance imaging to chart the
colour pathways in the human brain beyond V4. We asked subjects to view objects
that were dressed in natural and unnatural colours as well as their achromatic
counterparts and compared the activity produced in the brain by each condition.
The results showed that both naturally and unnaturally coloured objects activate
a pathway extending from V1 to V4, though not overlapping totally the activity
produced by viewing abstract coloured Mondrian scenes. Normally coloured objects
activated, in addition, more anterior parts of the fusiform gyrus, the
hippocampus and the ventrolateral frontal cortex. Abnormally coloured objects, by
contrast, activated the dorsolateral frontal cortex. A study of the cortical
covariation produced by these activations revealed that activity in large parts
of the occipital lobe covaried with each. These results, considered against the
background of previous physiological and clinical studies, allow us to discern
three broad cortical stages of colour processing in the human brain. The first is
based on V1 and possibly V2 and is concerned mainly with registering the presence
and intensity of different wavelengths, and with wavelength differencing. The
second stage is based on V4 and is concerned with automatic colour constancy
operations, without regard to memory, judgement and learning. The third stage,
based on the inferior temporal and frontal cortex, is more concerned with object
colours. The results we report, as well as the schema that we suggest, also allow
us to reconcile the computational theory of Land, implemented without regard to
cognitive factors such as memory and learning, and the cognitive systems of
Helmholtz and Hering, which view such factors as critical in the determination of
colours.
PMID- 9762957
TI - Autosomal dominant cerebellar ataxia type I. MRI-based volumetry of posterior
fossa structures and basal ganglia in spinocerebellar ataxia types 1, 2 and 3.
AB - Twenty-six patients suffering from autosomal dominant cerebellar ataxia type I
were subjected to a genotype-phenotype correlation analysis using molecular
genetic assignment to the genetic loci for spinocerebellar ataxia type 1, 2 or 3
(SCA1, SCA2, SCA3) and MRI-based volumetry of posterior fossa structures and
basal ganglia nuclei. There was significant atrophy of the cerebellum and
brainstem in all three SCA mutations compared with a group of 31 age- and sex
matched controls. Comparison between the SCA groups showed that cerebellar and
brainstem atrophy was more severe in SCA2 than in SCA1 and SCA3. Putaminal and
caudate volume was reduced only in SCA3, but not in SCA1 and SCA2. A set of three
morphological criteria was defined that enabled us to assign all SCA2 and SCA3
patients correctly to the underlying genotype. In contrast, these criteria did
not distinguish SCA1 from SCA2 and SCA3. Regression analysis failed to reveal a
significant association between CAG repeat length and the volumes of the
respective brain structures in any of the SCA mutant types. The present data
provide in vivo evidence that SCA2 and SCA3 lead to distinct patterns of brain
atrophy, while the atrophy changes in SCA1 overlap with both SCA2 and SCA3.
PMID- 9762958
TI - The role of the human motor cortex in the control of complex and simple finger
movement sequences.
AB - We evaluated the effects of high-frequency repetitive transcranial magnetic
stimulation (rTMS) over the primary motor cortex (M1) at different stimulus
intensities on finger sequences of varying complexity. Eighteen subjects played
unimanual finger sequences of different complexity on an electronic piano. For
each finger sequence, 16 notes were played to the 2 Hz beat of a metronome. After
the first four notes, rTMS was applied to the scalp location overlying the hand
motor representation for approximately 2 s. Accuracy and timing errors were
analysed. Stimulation over the M1 had a differential effect on sequences of
different complexity. Stimulus intensities capable of disrupting the performance
of a complex sequence did not affect simple sequences. To disrupt simple
sequences, the stimulus strength had to be augmented. This effect was
characteristic of the contralateral M1 position (five other scalp locations were
also stimulated). It is argued that the differential effect of rTMS on simple and
complex sequences is probably due to interference with M1 function. Interference
with the lateral premotor cortex (PMC) may play an additional role. The
particular relevance of the M1 is supported by results in a patient with PMC
stroke. The present findings suggest that the human M1 plays a greater role in
the performance of complex than of simple finger movement sequences. One possible
explanation could be that the human M1 is not only an executive motor area but
can also contribute to movement sequence organization.
PMID- 9762959
TI - Regional sympathetic function in high spinal cord injury during mental stress and
autonomic dysreflexia.
AB - Centrally mediated sympathetic stimulation of subjects who have suffered a spinal
cord injury (SCI) does not activate the decentralized part of the body below the
level of the lesion, whereas experimental data indicate an exaggerated response
above the level of the lesion. SCI subjects may exhibit an autonomic dysreflexia
reaction following afferent stimulation below the level of the lesion. In order
to investigate the function of the sympathetic nervous system above and below the
level of the lesion, regional noradrenaline spillover was measured by means of
steady-state isotope dilution technique above (forearm) and below (leg) the level
of the lesion at baseline, during mental stress and following bladder stimulation
in nine SCI subjects (mean age 41 years; level of injury C7-T4; mean duration of
injury 13.8 years). The results from the SCI subjects were also compared with
those from 10 weight- and age-matched control subjects, both at rest and during
mental stress. Body composition was determined by dual energy X-ray
absorptiometry scanning and arm/leg blood flow by occlusion plethysmography. At
baseline, total and regional noradrenaline spillover did not differ between the
groups. Mental stress increased mean arterial pressure in both groups. Heart rate
(76 versus 64 beats/min; P < 0.05) and arm noradrenaline spillover (2.73 versus
1.71 pmol/min/100 g; P < 0.05) increased more in spinal cord injury subjects than
in control subjects, whereas total body (2826 versus 3783 pmol/min; P < 0.01) and
leg noradrenaline spillover (0.23 versus 0.41 pmol/min/100 g; P < 0.05) increased
only in the control group. During bladder stimulation, SCI subjects reacted with
a marked increase in mean arterial pressure and leg noradrenaline spillover (from
0.06 to 0.91 pmol/min/100 g; P < 0.05) and their leg blood flow decreased.
Regional and total noradrenaline clearance were similar in the two groups. In
conclusion, peripheral afferent stimulation below the level of the lesion in
spinal cord injury subjects gives rise to a marked noradrenaline spillover from
the decentralized part of the sympathetic nervous system suggesting a remaining,
but qualitatively altered, neuronal function. Centrally mediated stimulation
induced an exaggerated response above the level of the lesion.
PMID- 9762960
TI - Writing disorders in Italian aphasic patients. A multiple single-case study of
dysgraphia in a language with shallow orthography.
AB - We report results of a writing task given to 53 mildly to moderately aphasic
Italian subjects. The task was designed to test the writing performance along the
subword-level routine for the spelling of regular words and non-words, and along
the lexical routine for the spelling of irregular words. The aim of the study was
to identify the incidence of different dysgraphic subtypes in Italian, a language
that is considered to have shallow orthography. Its spelling, however, is not
completely free of ambiguity. A five-part writing task was used: (i) words with
regular one-sound-to-one-grapheme conversion; (ii) words with regular syllabic
conversion; (iii) words with ambiguous transcription; (iv) loan-words; and (v)
non-words. For regular words, the effects of word length and word frequency, and
of the variables determining the complexity of the acoustic-to-phonological
conversion (continuant versus plosive phones; consonant-vowel sequence versus
doubled consonants or consonant clusters) were also considered. Patients'
performances were classified according to the presence of a dissociation between
(i) regular words and non-words, (ii) regular words and words with unpredictable
spellings, and (iii) one-to-one and syllabic conversions. The 53 aphasic patients
span the whole spectrum of dysgraphic taxonomy. Thirty-nine patients, in
particular, manifested a dissociated pattern of performance. Eighteen patients
showed a prevalent surface dysgraphic pattern and seven a phonological one, while
11 patients showed a mixed pattern (i.e. a better performance for regular words
than for ambiguous words or regular non-words). Three patients showed a specific
deficit for regular syllabic conversion rules only. A high rate of 'mixed
dysgraphia' suggests either a mutual interaction of the two impaired routines
when regular words are written, or two separate functional lesions: one at the
level of the auditory-to-phonological conversion procedure, the other at the
level of the orthographic output lexicon.
PMID- 9762962
TI - Reciprocal inhibitory visual-vestibular interaction. Visual motion stimulation
deactivates the parieto-insular vestibular cortex.
AB - The vestibular system--a sensor of head accelerations--cannot detect self-motion
at constant velocity and thus requires supplementary visual information. The
perception of self-motion during constant velocity movement is completely
dependent on visually induced vection. This can be linear vection or circular
vection (CV). CV is induced by large-field visual motion stimulation during which
the stationary subject perceives the moving surroundings as being stable and
himself as being moved. To determine the unknown cortical visual-vestibular
interaction during CV, we conducted a PET activation study on CV in 10 human
volunteers. The PET images of cortical areas activated during visual motion
stimulation without CV were compared with those with CV. Hitherto, CV was
explained neurophysiologically by visual-vestibular convergence with activation
of the vestibular nuclei, thalamic subnuclei and vestibular cortex. If CV were
mediated by the vestibular cortex, one would expect that an adequate visual
motion stimulus would activate both the visual and vestibular cortex. Contrary to
this expectation, it was shown for the first time that visual motion stimulation
with CV not only activates a medial parieto-occipital visual area bilaterally,
separate from middle temporal/medial superior temporal areas, it also
simultaneously deactivates the parieto-insular vestibular cortex. There was a
positive correlation between the perceived intensity of CV and relative changes
in regional CBF in parietal and occipital areas. These findings support a new
functional interpretation: reciprocal inhibitory visual-vestibular interaction as
a multisensory mechanism for self-motion perception. Inhibitory visual-vestibular
interaction might protect visual perception of self-motion from potential
vestibular mismatches caused by involuntary head accelerations during locomotion,
and this would allow the dominant sensorial weight during self-motion perception
to shift from one sensory modality to the other.
PMID- 9762961
TI - Limb-girdle muscular dystrophy in Guipuzcoa (Basque Country, Spain).
AB - The concept of limb-girdle muscular dystrophy (LGMD) is changing rapidly due to
the advances in molecular genetics. Recently, seven different gene loci have been
described, demonstrating that limb-girdle muscular dystrophy is a heterogeneous
syndrome, which includes different diseases with a similar phenotype. In isolated
populations which have little genetic exchange with neighbouring populations, an
accumulation of cases may be found. We carried out an epidemiological study in
Guipuzcoa, a small mountainous Basque province in northern Spain, and found the
highest prevalence rate of LGMD described so far: 69 per million. Genetic studies
demonstrated that 38 cases corresponded to the LGMD2A type, due to calpain-3 gene
mutations. Only one patient with alpha-sarcoglycanopathy was found, and in 12
patients the genetic defect was not identified. Moreover, the particular calpain
3 mutation predominant in Basque chromosomes (exon 22, 2362AG-->TCATCT), has only
been rarely found in the rest of the world. This observation strongly suggests a
founder effect in the indigenous population of Guipuzcoa. The clinical
characteristics of the patients with calpain-3 gene mutations were quite
homogeneous and different from the other groups (sarcoglycanopathy and unknown
gene defect), allowing for a precise clinical diagnostic. The disease onset was
between the ages of 8 and 15 years, in most cases in the pelvic girdle, and the
patients became wheelchair-bound between 11 and 28 years after onset. No
pseudohypertrophy of calves or contractures were observed. No clear correlations
were found between the nature and site of the mutation and the resulting
phenotype.
PMID- 9762963
TI - The spatial distribution of visual attention in hemineglect and extinction
patients.
AB - We studied the visual field distribution of speed and accuracy of manual
responses to small brief light flashes, in patients with left hemineglect or
extinction resulting from right hemisphere vascular lesions and in brain-damaged
and healthy control subjects. All patients with right hemisphere lesions showed a
greater impairment in both the speed of response and the detection rate in the
contralesional than in the ipsilesional hemifield. This interfield difference
increased with the eccentricity of stimulus presentation and was especially
pronounced in neglect patients who showed a paradoxical increase in speed of
response and detection rate at increasingly larger eccentricities in the
ipsilesional hemifield. We hypothesize that both the contralesional slowing down
and the ipsilesional speeding up of the response depends upon an exaggerated
gradient of attention towards the ipsilesional hemifield. To assess whether these
abnormalities concern automatic or controlled attentional processes, in a second
experiment, we manipulated the predictability of the side of the stimulus
presentation by using blocked rather than randomized stimulus presentations. This
resulted in a speeding up of responses in both hemifields thus showing that the
patients were able to focus attention to the side of stimulus presentation
voluntarily. However, there was no modification of the contra-ipsilesional
differences which, therefore, are likely to be related to abnormal automatic
processes rather than controlled attention.
PMID- 9762964
TI - Precision grip and Parkinson's disease.
AB - In order to investigate sensorimotor processing and force development in
Parkinson's disease, 16 patients, four patients with hemiparkinsonism and 12 age
matched normal subjects were assessed during lifting and holding of an object in
a precision grip between thumb and forefinger, or holding the object in this grip
at a fixed height above a table. In the former case, object loading could be
changed between lifts without warning. In the latter case, unexpected step load
changes to the object were applied to the object with a torque motor. All
procedures could be applied with or without visual control of the hand and the
object. Normal subjects lifted an unpredictable load employing the grip force
parameters used in the preceding lift. If a load change was encountered, the
parameters became adapted to the new conditions during the lift, modulating grip
forces to match the loading. Parkinsonian patients retained this strategy and the
ability to regulate grip forces according to load. Under all conditions, however,
parkinsonian subjects developed abnormally high grip forces in both the lift and
the hold phase, although the ratio of these forces remained normal. Lifting
height was normal in parkinsonian subjects, but the duration of the lifting task
was significantly prolonged, due to a marked slowing in the rate of grip force
development in the lead-up to object lift-off and to prolongation of the movement
phase. Forewarning of object loading, with or without visual control, did not
reduce timing deficits or improve the rate of grip force development. However, it
did allow parkinsonian subjects to reduce the safety margin significantly.
Responses to step load changes imposed during holding without visual control
showed minor abnormalities in the parkinsonian patients: onset latencies and EMG
activity in the first dorsal interosseus and thenar muscles were normal up to 140
ms after displacement. Subsequent EMG activity in the first dorsal interosseus
remained largely normal, but activity later in the slip response (140-210 ms),
subject to voluntary influence, was reduced in the thenar muscle. Differences
were less marked under visual conditions, but remained significant. We concluded
that the internal parameter set for lifting an object in a precision grip and the
automatic processes adapting precision grip to actual conditions are intact in
Parkinson's disease. However, parkinsonian subjects generate abnormally high grip
forces and require longer than normal subjects to complete a lift, particularly
with lighter loads. This deterioration in performance reflects both reduced
effectiveness of sensorimotor processing and impairment in the rate of force
development in Parkinson's disease.
PMID- 9762965
TI - Neurophysiological evidence of neuroplasticity at multiple levels of the
somatosensory system in patients with carpal tunnel syndrome.
AB - The human somatosensory cortex (S1) is capable of modification after partial
peripheral deafferentation, but it is not known whether spinal and brainstem
changes contribute to this process. We recorded spinal, brainstem and cortical
somatosensory evoked potentials following ulnar nerve stimulation in patients
affected by unilateral carpal tunnel syndrome with EMG evidence of chronic
alterations in median nerve sensorimotor conduction at the wrist lasting at least
4 weeks, and compared them with those from the unaffected hand and with those
obtained in a control group. Amplitudes of spinal N13 and brainstem P14
potentials following stimulation of the ulnar nerve ipsilateral to the
deafferented median nerve were greater than those following stimulation of the
contralateral ulnar nerve. Side-to-side amplitude differences in N13 and P14 were
greater in patients than in the control group. Parietal N20 and P27 potentials,
supposedly generated in S1, were also significantly increased. The present
results suggest that a chronic pathological modification of peripheral
sensorimotor inputs is associated with changes in neural activity at multiple
sites of the somatosensory system. Changes in spinal and brainstem structures
could contribute to the mechanisms subserving changes in the S1. Changes in
synaptic strength and unmasking inputs secondary to disconnection of the normally
dominant inputs to the 'median nerve' cortex may be the mechanisms underlying
ulnar nerve SEP changes.
PMID- 9762966
TI - Interhemispheric neural summation in the absence of the corpus callosum.
AB - One subject with full forebrain commissurotomy (L.B.), two with callosotomy (J.W.
and M.E.), one with callosal agenesis (R.B.) and 10 normal subjects performed a
simple reaction time task in which visual stimuli were either presented singly in
one or other visual field, or in both visual fields simultaneously. Reaction
times were faster to double stimuli than to single ones, but in the normal
subjects this 'redundancy gain' did not exceed that predicted by probability
summation (the horse-race model). In the four subjects lacking the corpus
callosum, the gain did exceed that predicted by probability summation when the
stimuli were brighter than the background, implying subcortical neural summation.
In the three surgical cases (L.B., J.W. and M.E.) the gain was greatly diminished
when the stimuli were equiluminant with the background, suggesting that neural
summation occurred at the collicular level. In normal subjects, callosal transfer
may ensure that at least some degree of interhemispheric neural summation occurs,
even with unilateral input. The acallosal subject (R.B.) was anomalous in that
neural summation was not diminished by equiluminance.
PMID- 9762967
TI - Just when you think you've seen it all: the imaging evolution.
PMID- 9762968
TI - The situation of diagnostic radiology training programs and their graduates in
1997.
AB - OBJECTIVE: In light of concerns about the job market, the American College of
Radiology studied the employment situation of 1997 graduates from diagnostic
radiology training programs and the status and plans of these programs. MATERIALS
AND METHODS: In an April-May 1997 survey and in a December 1997 follow-up, the
American College of Radiology asked a 50% random sample of diagnostic radiology
residency directors about their programs and about the employment situation of
their 1997 residency and fellowship graduates. Of those surveyed, 89% responded.
We compared these findings with those from a similar 1996 survey. The test of
statistical significance was p < or = .05. RESULTS: All diagnostic residency and
fellowship graduates who wanted to work were employed within 6 months after
graduation. Approximately 95% of graduates had positions that directors believed
to reasonably match their training and personal employment goals. Outcomes were
similar across all fellowship fields except nuclear medicine, a field in which
graduates had greater difficulty finding jobs. The completed plus planned changes
in program size will lead to a 13-14% reduction in the annual number of
graduates. As in previous years, by late April to mid May 1997, 93% of beginning
year residency slots were filled. However, the percentage of beginning residents
who are international medical graduates increased. In 1997, residency program
directors were more optimistic about graduates' job prospects than in 1996, and
there was a statistically significant increase from 1996 in the proportion of
fellowship graduates, according to directors, who had found jobs that fit their
goals and training. CONCLUSION: Unemployment continues to be low. The 1997 job
market has improved over the 1996 job market, but job prospects in nuclear
medicine continue to be more problematic than in other subspecialties.
PMID- 9762969
TI - Constructing a curriculum vitae: the radiologist's resume.
PMID- 9762970
TI - False-negative core biopsy of the breast.
PMID- 9762971
TI - Preston Hickey lecture. We are radiologists.
PMID- 9762972
TI - Current concepts in contrast media-induced nephropathy.
PMID- 9762973
TI - Correlation of dynamic contrast-enhanced MR imaging with histologic tumor grade:
comparison of macromolecular and small-molecular contrast media.
AB - OBJECTIVE: The endothelial integrity of microvessels is disrupted in malignant
tumors. Quantitative assays of tumor microvascular characteristics based on
dynamic MR imaging were correlated with histopathologic grade in mammary soft
tissue tumors. MATERIALS AND METHODS: A spectrum of tumors, benign through highly
malignant, was induced in 33 female rats by administration of N-ethyl-N
nitrosourea, a potent carcinogen. Dynamic contrast-enhanced MR imaging was
performed using a small-molecular contrast medium (gadopentetate, molecular
weight = 0.5 kDa) and a macromolecular contrast medium (albumin-(Gd-DTPA)30,
molecular weight = 92 kDa) at an interval of 1-2 days. Permeability surface area
product (PS), as estimated by the corresponding endothelial transfer coefficient
(K(PS)), and fractional plasma volume (fPV) were calculated for each tumor and
each contrast agent using a two-compartment bidirectional kinetic model. MR
imaging microvascular characteristics were correlated with histopathologic tumor
grade. RESULTS: Tumor permeability to macromolecular contrast medium,
characterized by K(PS), showed a highly positive correlation with tumor grade (r2
= .76, p < 10(-10)). K(PS) values were zero for all benign and some low-grade
carcinomas, greater than zero in all other carcinomas, and increased in magnitude
with higher tumor grade. A considerably smaller but significantly positive
correlation was found between fPV and tumor grade using macromolecular contrast
medium (r2 = .25, p < .003). No correlation between K(PS) or fPV values and tumor
grade was found using gadopentetate (r2 = .01, p > .95 and r2 = .03, p > .15,
respectively). CONCLUSION: Quantitative tumor microvascular permeability assays
generated with macromolecular MR imaging contrast medium correlate closely with
histologic tumor grade. No significant correlation is found using small-molecular
gadopentetate.
PMID- 9762974
TI - The role of helical CT in the assessment of cervical spine injuries.
PMID- 9762975
TI - The cost-effectiveness of oblique radiography in the exclusion of C7-T1 injury in
trauma patients.
AB - OBJECTIVE: The purpose of our study was to compare the cost-effectiveness of
bilateral oblique radiography with that of CT for excluding C7-T1 injury in
trauma patients. MATERIALS AND METHODS: Using a historical cohort model, we
retrospectively studied two distinct groups of trauma patients. In the first
group, which included 196 patients, CT was performed to show C7-T1 anatomy when
this region was not adequately revealed on initial three-view cervical spine
radiography. In the second group, which included 129 patients, routine three-view
radiography was complemented by bilateral oblique views. If these five views
failed to adequately reveal C7-T1 anatomy, CT was then performed to show the
cervicothoracic junction. Using Medicare reimbursement data, we then compared the
cost-effectiveness of CT with that of oblique radiography in terms of cost per
cervical spine imaged completely to the level of C7-T1. RESULTS: In the first
group, 50 (26%) of 196 patients underwent CT when C7-T1 anatomy was not
adequately revealed on routine three-view cervical spine radiography. In the
second group, only 17 (13%) of the 129 patients required CT when five-view
radiography failed to adequately reveal C7-T1 anatomy. This difference was
statistically significant (p < .01). The cost per completely imaged cervical
spine was $92.00 when bilateral oblique radiographs were routinely obtained,
compared with $116.28 per completely imaged cervical spine when these views were
not obtained. CONCLUSION: Because bilateral oblique radiography appears to be
cost-effective for the exclusion of cervical spine injuries, we suggest that it
be performed routinely.
PMID- 9762976
TI - MR imaging of tears of discoid lateral menisci.
AB - OBJECTIVE: The purpose of this study was to determine the positive predictive
value (PPV) for diagnosis of discoid lateral meniscal tear using MR imaging and
to describe various patterns of such tears in the knee. SUBJECTS AND METHODS: MR
reports of 77 patients (10-67 years old) who underwent prospective MR imaging
that led to a diagnosis of discoid lateral meniscal tear were correlated with
arthroscopic results. MR images obtained in 71 patients confirmed to have discoid
lateral meniscial tear were retrospectively reviewed for the presence, site, and
pattern of discoid lateral meniscal tear, including type of displacement of the
torn segment. MR abnormalities were correlated with arthroscopic findings.
RESULTS: For the prospective MR interpretations, the PPV for discoid meniscus was
92%. PPV for discoid meniscal tear was 57%. PPVs for individual types of discoid
meniscal tears were 46% (peripheral tear, 19/41), 76% (peripheral tear with
horizontal tears, 16/21), 56% (horizontal tear, 5/9), 50% (transverse tear, 1/2),
67% (horizontal tear combined with transverse tear, 2/3), and 100% (longitudinal
tear, 1/1). Peripheral tear alone and peripheral tear with horizontal tear were
the most common types of tears (n = 20, 28%). Multiple tears (n = 34, 48%) were
common. Displacement of the torn segments was seen in 51 patients (72%).
CONCLUSION: MR imaging has a low PPV for diagnosing discoid lateral meniscal
tear. Peripheral tear alone and peripheral tear with horizontal tear were the
most common types of tears, and displacement of the torn segment was frequent.
PMID- 9762977
TI - Normal and abnormal medial meniscocapsular structures: MR imaging and sonography
in cadavers.
AB - OBJECTIVE: The purpose of this study was to develop imaging criteria for the
diagnosis of meniscocapsular separation by correlating findings on MR imaging, MR
arthrography, and sonography of normal and abnormal medial meniscocapsular
structures with corresponding anatomic sections in cadavers. MATERIALS AND
METHODS: Eight cadaveric knee specimens were examined with MR imaging, MR
arthrography, and sonography before arthroscopy. In six specimens the following
lesions were arthroscopically created: meniscocapsular separation (n = 3), medial
collateral ligament (MCL) tear (n = 3), tear of the meniscofemoral extension of
the deep MCL (n = 2), and coronary ligament tear (n = 2). After arthroscopy, all
imaging studies were repeated. The specimens were sectioned for correlation with
imaging studies. RESULTS: MR findings that correlated with meniscocapsular
separation were interposition of fluid between the meniscus and the MCL,
irregular meniscal outline, and increased distance between the meniscus and the
MCL. On MR arthrography meniscocapsular separation correlated with interposition
of contrast medium between the meniscus and the MCL. Tears of the meniscofemoral
extension of the deep MCL were best shown on MR arthrography. Sonography showed
deep and superficial MCL lesions but did not show meniscocapsular separations.
CONCLUSION: In arthroscopically created meniscocapsular separation, the lesion is
suggested on MR images when fluid is interposed between the meniscus and the MCL,
when the meniscal outline is irregular, or when the distance between the meniscus
and the MCL is increased. On MR arthrograms, a meniscocapsular separation is
suggested when contrast medium is interposed between the meniscus and the MCL.
Sonography does not allow accurate diagnosis of meniscocapsular separation.
PMID- 9762978
TI - Elastofibroma dorsi: prevalence in an elderly patient population as revealed by
CT.
AB - OBJECTIVE: We wanted to determine the prevalence and appearance of elastofibroma
dorsi in an elderly patient population (n = 258) who underwent CT of the chest
for reasons other than to evaluate posterolateral chest wall pain, stiffness, or
a mass. CONCLUSION: Five elastofibromas were detected in four patients; none of
these elastofibromas were noted at initial examination. Our study suggests that
the prevalence of elastofibroma dorsi revealed by CT is 2%, which is lower than
the 11-24% found in autopsy series but higher than expected for such a rare
tumor. Elastofibroma dorsi typically has a layered appearance on CT; however, in
our study, homogeneous soft-tissue attenuation was noted. The diagnosis is often
missed prospectively. Familiarity with the location and imaging appearance of
elastofibroma dorsi may enhance detection and characterization of posterolateral
chest wall masses in elderly patients.
PMID- 9762979
TI - Vascular leiomyoma of an extremity: MR imaging-pathology correlation.
AB - OBJECTIVE: The objective of our study was to analyze MR images of vascular
leiomyoma of the extremity and to compare these images with histopathologic
findings to determine if a correlation exists. CONCLUSION: T2-weighted MR images
of vascular leiomyoma of an extremity showed a mass with mixed areas that were
both hyper- and isointense to skeletal muscle and also revealed a hypointense
rim; these images correlate with histopathologic findings of smooth muscle,
vessels, fibrous tissue, an intravascular thrombus, and a fibrous capsule.
PMID- 9762981
TI - Osteonecrosis of the knee in an HIV-infected patient.
PMID- 9762980
TI - Rapid diagnosis and treatment of a traumatic atlantooccipital dissociation.
PMID- 9762982
TI - CT colonography with three-dimensional problem solving for detection of colonic
polyps.
AB - OBJECTIVE: We performed CT colonography in patients referred for conventional
colonoscopy, interpreted the axial images, and used commercially available
software to reconstruct endoluminal perspective views to differentiate polyps
from folds. SUBJECTS AND METHODS: We prospectively examined 44 patients (27 men
and 17 women; mean age, 58 years old) with CT colonography by interpreting the
axial images and using three-dimensional rendering for problem solving only. The
CT scans were interpreted by two radiologists who were unaware of patients'
histories as revealed by colonoscopic findings. The findings on colonography were
compared with those of conventional colonoscopy to determine sensitivity,
specificity, time spent on interpretation, and confidence of interpretation.
RESULTS: Colonoscopy showed normal findings in 28 patients and 22 polyps in the
remaining 16 patients. Six polyps were 8 mm or larger, three were 5-7 mm, and 13
were 5 mm or smaller. The findings of the two observers revealed an overall
sensitivity of 50% and 38%, respectively, and a specificity of 93% and 86%,
respectively. Sensitivity for polyps larger than 8 mm was 83% and specificity was
100% for both observers. The average amount of time spent on interpretation was
28 min 30 sec (range, 14-65 min). Both observers used the endoluminal view for
differentiating folds from polyps in 23 (52%) of 44 patients, which had only
minimal impact on interpretation time. CONCLUSION: CT colonography can be
performed and the images interpreted using currently available hardware and
software by initially using the axial images to search for polyps of significant
size. Endoluminal views should be used only when necessary to help distinguish
normal folds from fixed raised lesions that are suggestive of polyps.
PMID- 9762983
TI - Using unenhanced helical CT with enteric contrast material for suspected
appendicitis in patients treated at a community hospital.
AB - OBJECTIVE: We evaluated the accuracy of unenhanced helical CT with enteric
contrast material in the diagnosis of appendicitis in children and adults treated
at a community hospital. SUBJECTS AND METHODS: Over an 8-month period, 100
consecutive patients with right lower quadrant pain and suspected appendicitis
were prospectively evaluated. Thin-collimation helical CT scanning was performed
after administration of enteric contrast material. CT interpretations were
correlated with surgical pathology (45 patients) and clinical follow-up (55
patients). RESULTS: The findings of 33 CT scans were interpreted as positive for
appendicitis (29 true-positives and four false-positives), and the findings of 67
were interpreted as negative for appendicitis (66 true-negatives and one false
negative). Sensitivity was 97%, specificity was 94%, accuracy was 95%, positive
predictive value was 88%, and negative predictive value was 99%. In the 67 CT
scans with negative findings for appendicitis, an alternative diagnosis was made
for 36 patients (54%). CONCLUSION: Unenhanced helical CT with enteric contrast
material for the evaluation of appendicitis can be implemented in a community
hospital. In our study, such imaging achieved excellent accuracy.
PMID- 9762984
TI - Small-bowel perforation by a foreign body.
PMID- 9762985
TI - Performing radiologic gastrostomy or gastrojejunostomy in patients with malignant
ascites.
AB - OBJECTIVE: We describe our protocol for performing decompression radiologic
gastrostomy and gastrojejunostomy in patients with ascites and small-bowel
obstruction. We also assess the technical success rate, the complications, and
the morbidity and mortality in 45 patients who underwent radiologic gastrostomy.
MATERIALS AND METHODS: Forty-five consecutive patients with ascites associated
with metastatic ovarian cancer underwent a radiologic gastrostomy or
gastrojejunostomy with gastropexy. Six patients underwent gastrostomy, and 39
patients underwent gastrojejunostomy. Locking catheters were placed using the
Seldinger technique after gastropexy in all patients. Paracentesis was performed
before gastrostomy or gastrojejunostomy. Additional serial paracenteses were
performed after the procedure when reaccumulation of ascites close to the site of
gastropexy was detected on follow-up sonography. RESULTS: Forty-five procedures
were attempted. The technical success rate was 97.8%. The complication rate was
15.6%. Three major complications (6.7%) and four minor complications (8.9%)
occurred. One procedure-related death (2.2%) occurred 16 days after
gastrojejunostomy. CONCLUSION: Radiologic gastrostomy and gastrojejunostomy can
be performed safely in patients with ascites if the patients undergo paracentesis
first and if the reaccumulation of ascites is prevented after tube placement. In
patients with ascites, gastropexy plays an important role in preventing
pericatheter leakage. Ascites and peritoneal carcinomatosis should not be
considered contraindications for radiologic gastrostomy or gastrojejunostomy.
PMID- 9762986
TI - Abdominal manifestations of posttransplantation lymphoproliferative disorder.
AB - The abdominal manifestations of posttransplantation lymphoproliferative disorder
show wide variability with potential involvement of all organ systems. The
radiologist should be aware of this entity when evaluating patients who have
undergone transplantation; both clinical and radiologic findings can mimic other
disease processes. Suggestive lesions should prompt a search for additional areas
of involvement. In our experience, although sonography can reveal
posttransplantation lymphoproliferative disorder of the abdominal viscera, CT
more adequately depicts the full extent of disease involvement. Distinguishing
between monomorphic and polymorphic subtypes, though important for treatment
planning, is not possible by imaging characteristics alone. Therefore, tissue
diagnosis is warranted.
PMID- 9762987
TI - Gas lock obstruction of the colon: Ogilvie's syndrome revisited.
PMID- 9762988
TI - Peritoneal encapsulation: CT appearance.
PMID- 9762989
TI - Hepatic cavernous hemangioma: sonographic patterns and speed of contrast
enhancement on multiphase dynamic MR imaging.
AB - OBJECTIVE: Our purpose was to investigate a correlation between the speed of
contrast enhancement in patients with hepatic cavernous hemangioma revealed by
dynamic MR imaging and the internal echo pattern revealed by sonography.
MATERIALS AND METHODS: Forty-five patients underwent multiphase IV contrast
enhanced dynamic MR imaging that revealed 71 hepatic cavernous hemangiomas less
than 4 cm in diameter; the MR findings were compared with the sonographic
findings in these patients. On MR imaging, the hemangiomas were classified as
rapid-, intermediate-, and slow-enhancing. We classified sonographic features as
hypoechoic, iso- or mixed-echoic, and hyperechoic according to the relative
echogenicity seen between lesions and the surrounding hepatic parenchyma.
Sonographic patterns and MR imaging findings of individual lesions were then
compared. RESULTS: Rapid-enhancing hemangiomas revealed on dynamic MR imaging
tended to be hypoechoic on sonography (18/24, 75%; p = .0143), and lesions that
were slow-enhancing on MR imaging tended to be hyperechoic (26/29, 90%; p <
.0001). Hypoechoic lesions on sonography tended to be rapid-enhancing on dynamic
MR imaging (18/18, 100%). Likewise, hyperechoic lesions on sonography tended to
be slow-enhancing on MR imaging (26/33, 79%; p = .0009). CONCLUSION: In most
patients with hepatic cavernous hemangiomas, we found that the speed of contrast
enhancement on multiphase dynamic MR imaging enabled us to predict the echo
pattern in sonography and vice versa.
PMID- 9762990
TI - MR cholangiography in primary sclerosing cholangitis.
AB - OBJECTIVE: The purpose of this study was to evaluate the ability of MR
cholangiography to reveal the characteristics of biliary abnormalities found in
primary sclerosing cholangitis. CONCLUSION: Our results suggest that MR
cholangiography could be useful in the diagnosis of primary sclerosing
cholangitis. Slightly dilated peripheral bile ducts unconnected to the central
ducts in several hepatic segments are a characteristic MR sign of primary
sclerosing cholangitis. However, other studies are necessary to establish the
usefulness of MR cholangiography in relation to other imaging techniques for
evaluating primary sclerosing cholangitis.
PMID- 9762992
TI - Immediate increase in arterial blood flow in embolized hepatic segments after
portal vein embolization: CT demonstration.
AB - OBJECTIVE: This study was conducted to determine whether an immediate change
occurs in the blood flow distribution in hepatic segments after segmental portal
vein embolization. CONCLUSION: We found an immediate change in the distribution
of blood flow in the liver after embolization; with portal vein embolization, we
found an immediate increase in the hepatic artery blood flow in the affected
segments.
PMID- 9762991
TI - Percutaneous hepatic infarction therapy for hepatocellular carcinoma.
AB - OBJECTIVE: We percutaneously injected ethanol into small vessels afferent to
tumor nodules to induce hepatic infarction in areas of tumor caused by
hepatocellular carcinoma. CONCLUSION: Percutaneous hepatic infarction therapy
holds promise as a new method of treating large hepatocellular carcinoma.
PMID- 9762993
TI - Techniques for transjugular intrahepatic portosystemic shunt revision.
PMID- 9762994
TI - Use of a new percutaneous thrombolytic device for percutaneous removal of biliary
stones.
PMID- 9762995
TI - Unenhanced helical CT of ureteral stones: a replacement for excretory urography
in planning treatment.
AB - OBJECTIVE: The purpose of this study was to determine whether unenhanced helical
CT alone can be used for diagnosis and treatment planning of patients with
obstructing ureteral stones. MATERIALS AND METHODS: Medical records of 100
patients with ureteral stones and a clearly discernible clinical outcome who had
undergone unenhanced helical CT were reviewed to determine the number of
urography procedures and results of excretory urograms performed within 72 hr of
helical CT. CT scans were then reviewed by two radiologists for six findings: in
plane stone diameter, z-axis stone diameter, location of stone, periureteral
stranding, hydronephrosis, and perinephric fluid. Seventy-one patients passed
stones spontaneously, and 29 patients required intervention including basket
retrieval, extracorporeal shock-wave lithotripsy, laser lithotripsy, or a
combination of the three treatments. Data were analyzed to determine those
findings that correlated with the need for intervention. RESULTS: Five excretory
urograms were obtained, all of which agreed with findings revealed by CT.
Excretory urography added no information. CT findings of in-plane diameter (p <
.001), z -axis diameter (p < .001), and location of stone (p = .003) all
significantly correlated with the need for intervention. CONCLUSION: Helical CT
can be used in place of excretory urography to plan treatment of patients with
flank pain caused by obstructing ureteral stones. Stones that are larger than 5
mm, located within the proximal two thirds of the ureter, and seen on two or more
consecutive CT images are more likely to require endoscopic removal, lithotripsy,
or both.
PMID- 9762996
TI - Characterization of urinary calculi: in vitro study of "twinkling artifact"
revealed by color-flow sonography.
AB - OBJECTIVE: The "twinkling artifact" is a color-flow sonographic artifact
described behind calcifications and presenting as a random color encoding in the
region where shadowing would be expected on gray-scale images. Our purpose was to
study the relationship between this twinkling artifact seen behind urinary stones
on color-flow sonography and the morphology or biochemical composition of these
urinary stones. MATERIALS AND METHODS: Forty-seven urinary stones were studied in
vitro with color-flow sonography. Transmit frequency, color gain, velocity range,
color filters, focal depth, and depth of field were changed during scanning. The
twinkling artifact was graded 0 when absent, 1 when present but occupying a
portion of acoustic shadowing, and 2 when occupying the entire acoustic
shadowing. Stones were studied under a binocular magnifying glass to characterize
the surface, and infrared spectrophotometry was used to determine the chemical
composition. RESULTS: Calculi of calcium oxalate dihydrate and calcium phosphate
always produced a grade 1 or grade 2 twinkling artifact. Absence of artifact was
noted only for calcium oxalate monohydrate and urate stones. In 100% of grade 0
calcium oxalate stones, the monohydrate compound was predominant (>93%). In 100%
of grade 2 calcium oxalate stones, the dihydrate compound was predominant (>75%).
For calcium oxalate stones, the surface pattern was correlated with their
composition. Sensitivity and specificity for absence of artifact, as indicative
of calcium oxalate monohydrate, were 60% and 83%, respectively, for all stones
and 56% and 100%, respectively, only for radiopaque stones. CONCLUSION: An in
vitro relationship exists between the twinkling artifact and the morphology of
urinary stones. Color-flow sonography could play a role in detecting dense
calcium oxalate monohydrate calculi, which in turn may help predict
fragmentability.
PMID- 9762997
TI - Cystic teratomas of the ovary: diagnostic value of sonography.
AB - OBJECTIVE: This study was undertaken to determine if the diagnosis of cystic
teratomas of the ovary can be made by experienced sonologists using only specific
associated sonographic features. MATERIALS AND METHODS: Two sonologists
independently reviewed the sonograms of 252 adnexal masses. For each mass, each
sonologist recorded sonographic features using a standardized checklist, which
included four descriptions associated with cystic teratomas. From a list of
diagnostic possibilities, each reviewer chose one specific conclusion, with
emphasis on achieving the highest combination of sensitivity and positive
predictive value for any particular diagnosis. The sensitivity, positive
predictive value, and positive likelihood ratio for the diagnosis of cystic
teratoma were evaluated for each sonographic finding and for each sonologist's
interpretation. RESULTS: Of the 252 masses, 74 cystic teratomas were found, 55 of
which showed two or more associated sonographic features. Each reviewer had a 98%
positive predictive value with 85% sensitivity for the diagnosis and
identification of cystic teratomas (positive likelihood ratio = 152). The
positive predictive value was 100% when an adnexal mass had two or more
sonographic features associated with dermoid masses. The positive predictive
value for individual sonographic features associated with dermoid masses was 80%
for a shadowing echodensity, 75% for regionally bright echoes, 50% for
hyperechoic lines and dots, and 20% for a fluid-fluid level. CONCLUSION: An
adnexal mass showing two or more of the sonographic features associated with
cystic teratomas can be confidently diagnosed as a cystic teratoma.
PMID- 9762998
TI - Renal lymphoma: spectrum of CT findings and potential mimics.
AB - Renal lymphoma has a broad spectrum of imaging manifestations. Typical patterns
of renal lymphoma include multiple renal masses, solitary masses, diffuse
infiltration, and invasion from contiguous retroperitoneal disease. Isolated
perirenal disease is probably the most atypical form of renal lymphoma and has a
variety of appearances, including small curvilinear densities and soft-tissue
nodules or plaques. In general, the CT diagnosis of renal lymphoma is not
difficult because most patients already have a known diagnosis of lymphoma.
Nevertheless, it is important to be familiar with both the typical and the
atypical manifestations of renal lymphoma because numerous disease processes,
normal variants, and artifacts may potentially mimic renal lymphoma.
PMID- 9762999
TI - Kaposi's sarcoma involving a transplanted kidney: CT findings.
PMID- 9763000
TI - Endovascular occlusion with a new mechanical detachable coil.
AB - OBJECTIVE: Metallic coils have been used for vascular embolization for many years
but controlled-release coils have only recently become commercially available.
Most of these devices are microcoils that were manufactured primarily for the
packing of intracerebral aneurysms; therefore, they lack radial force and are not
ideal agents for the occlusion of high-flow lesions such as pulmonary
arteriovenous malformations (PAVMs). The objective of this study was to review
our experience with a new detachable coil based on the conventional Gianturco
Wallace coil. SUBJECTS AND METHODS: The new detachable coil was initially used
for the treatment of varicocele in 20 patients. Subsequently, the coil was used
in 48 patients during 90 procedures for the treatment of PAVMs. RESULTS: A total
of 548 coils were used. Complete occlusion of the testicular vein was achieved in
all patients with varicocele. Successful occlusion of the PAVM being treated was
achieved in all patients, and no instances of recanalization were documented in
any of the patients who returned for follow-up angiography. Forty-one coils had
to be removed completely from the catheter before detachment because of
inappropriate size or position. Eight coils failed to detach easily, and six of
these had to be removed. Most of these device failures were associated with
kinking of the screw thread mechanism between the coil and the delivery wire.
CONCLUSION: The Jackson detachable coil allows safer, more accurate, and more
distal embolization of PAVMs than is possible with nondetachable coils.
Complications associated with its use have been few.
PMID- 9763001
TI - Venous rupture complicating hemodialysis access angioplasty: percutaneous
treatment and outcomes in seven patients.
AB - OBJECTIVE: To evaluate percutaneous treatment options for preserving hemodialysis
access after angioplasty-related venous rupture, we retrospectively reviewed the
charts for all dialysis access angioplasties performed over a 33-month period.
Seven cases of venous rupture after venous angioplasty were identified (four men
and three women; mean age, 63.5 years). Treatment included observation only (n =
1), a second prolonged balloon inflation at the rupture site (n = 2), stent
insertion (n = 5), and manual graft occlusion (n = 1). Treatment was successful
in eliminating contrast extravasation in all patients while maintaining immediate
graft function in six out of seven patients. None of the patients required
emergent surgical intervention. The mean primary and secondary patency rates of
the salvaged grafts after intervention were 2.3 and 9.3 months, respectively.
Five of seven access sites were still patent at the most recent follow-up.
CONCLUSION: Prolonged balloon inflation or placement of a stent may salvage
hemodialysis access in most patients after angioplasty-related venous rupture.
Primary and secondary patency have proven to be satisfactory.
PMID- 9763002
TI - Effect of anatomic distribution of pulmonary emboli on interobserver agreement in
the interpretation of pulmonary angiography.
AB - OBJECTIVE: This study examines the anatomic distribution of emboli on pulmonary
angiography and attempts to determine the relationship of vessel size to
interobserver agreement, two factors having important implications in comparing
pulmonary angiography with cross-sectional imaging for pulmonary embolism.
MATERIALS AND METHODS: One hundred twenty-five consecutive pulmonary angiograms
were reviewed retrospectively by three interventional radiologists. Initial
interpretations were recorded and compared to determine interobserver agreement
on a per-patient and per-embolus basis. Discordant interpretations were reviewed
by all radiologists for a consensus interpretation. RESULTS: Unanimous per
patient agreement occurred in 91% (114/125) of initial interpretations. The
largest artery containing acute pulmonary embolism was segmental or larger in 24
patients (83% of patients with acute positive findings, 19% of all patients) and
subsegmental in only five patients (17% and 4%, respectively). On a per-patient
basis, initial interobserver agreement averaged 45% and unanimous consensus
agreement was achieved for 79% of patients having isolated subsegmental pulmonary
embolism. Consensus readings altered initial per-patient interpretations for 30%
of patients having only subsegmental pulmonary embolism; per-embolus
interpretations were altered for 37% of all subsegmental emboli. CONCLUSION:
Subsegmental emboli occurring as isolated findings are relatively rare.
Approximately one third of subsegmental emboli and one third of patients having
isolated subsegmental emboli may be initially misdiagnosed on pulmonary
angiography. Objections to cross-sectional imaging for pulmonary embolism based
on the inability to detect subsegmental pulmonary embolism when compared with
pulmonary angiography should be reexamined with this data in mind.
PMID- 9763003
TI - Assessment of lung volumes using helical CT at inspiration and expiration:
comparison with pulmonary function tests.
AB - OBJECTIVE: This study was designed to determine lung volumes using inspiratory
and expiratory helical CT with two-dimensional (2D) and three-dimensional (3D)
postprocessing and to compare the accuracy of those measurements with pulmonary
function test results. SUBJECTS AND METHODS: Seventy-two patients with suspected
pulmonary disease underwent unenhanced helical CT (slice thickness, 8 mm; pitch,
2; increment, 8 mm) at deep inspiration and expiration. Lung volumes were
determined using either a 2D approach (semiautomatic segmentation; thresholds,
1024 and -200 H) or a 3D technique (double-threshold seeded volumes of interest;
thresholds, -1024 H [lower] and -900, -500, 400, -300, or -200 H [upper]).
Pulmonary function tests were available for correlation in all cases. RESULTS:
Using inspiratory helical CT, we underestimated total lung capacity by 12%, which
had a good correlation (r = .89) with static lung volumes. Volume revealed by
expiratory helical CT was equivalent to intrathoracic gas volume, which also
exhibited a good correlation (r = .88). However, using expiratory helical CT, we
overestimated residual volume by 850 ml with a rather good correlation (r = .77).
An emphysema index revealed moderate correlation with the relative forced
expiratory volume in 1 sec (inspiration, r = -.66; expiration, r = -.54), whereas
the expired volume showed a moderate correlation with the absolute forced
expiratory volume in 1 sec (r = .65). The 2D approach showed lower absolute
volumes than the 3D technique (mean, 3.6%; r = .99). In the 3D technique, lower
upper thresholds led to reduced volumes (170 ml/100 H). CONCLUSION: Inspiratory
and expiratory helical CT show high correlation with static lung volumes. The 3D
technique (-1024 to -200 H) is recommended for absolute estimation of lung
volumes.
PMID- 9763004
TI - Real-time CT fluoroscopy: usefulness in thoracic drainage.
AB - OBJECTIVE: The purpose of our study was to review the application of real-time CT
fluoroscopy in the drainage of localized pleural and mediastinal collections.
SUBJECTS AND METHODS: Between July 1996 and August 1997, 20 patients with 10
loculated pleural effusions, two mediastinal fluid collections, and 12 focal
pneumothoraces were treated using CT fluoroscopy. The patient population was 25
77 years old and included 14 men and six women. Methods of drainage included
using a modified Seldinger technique with a guidewire and serial dilators in 10
patients and a single-stick trocar technique in the remaining 14. Total room
time, procedure time, and CT fluoroscopy time were recorded. RESULTS: All 24
collections were successfully evacuated using either real-time or interrupted
real-time CT fluoroscopy. The real-time capability of CT fluoroscopy proved
particularly useful for rapid placement of drainage tubes in patients who were
unable to cooperate with breathing instructions and in patients who had a narrow
window of access. Average total room time was 65 min. Average procedure time was
32 min, and average CT fluoroscopy time was 143 sec. CONCLUSION: CT fluoroscopy
permits rapid drainage of intrathoracic collections. CT fluoroscopy is a
particularly useful treatment for patients who are unable to perform breath
holding or in whom access to the drainage site is difficult.
PMID- 9763005
TI - Imaging of oncologic patients: benefit of combined CT and FDG PET in the
diagnosis of malignancy.
AB - OBJECTIVE: The purpose of this study was to assess the benefit of combined CT and
18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in diagnosing
malignancy. MATERIALS AND METHODS: The records of 26 patients with intraabdominal
and intrathoracic neoplasms who underwent CT and FDG PET between January 1995 and
September 1996 were retrospectively reviewed. Most of these patients had
inconclusive findings on prior CT for the diagnosis of malignancy. Only sites of
potential malignant disease were included in the data analysis. Presence or
absence of malignancy was confirmed by histopathology or follow-up CT. Three
observers experienced in abdominal imaging used CT findings alone to estimate
level of suspicion (1 = definitely not malignant to 5 = definitely malignant) for
primary or recurrent neoplasms (n = 21), distant metastases (n = 25), and
neoplastic nodal involvement (n = 18). Six weeks later the three observers
reviewed the same CT examinations supplemented with FDG PET and reestimated
suspicion of malignancy. Receiver operating characteristic methodology was used
to analyze the results. Sensitivity, specificity, positive and negative
predictive values, and accuracy in diagnosis of malignant disease were calculated
using level 4 (probable malignancy) as the cutoff for the presence of disease.
RESULTS: The mean area under the receiver operating characteristic curve,
indicating successful diagnosis of malignancy, was .82 for CT alone and .92 for
CT with FDG PET (p < .05). The accuracies for diagnosis of primary or recurrent
neoplasms, distant metastases, and neoplastic nodal involvement were 62%, 68%,
and 83%, respectively, for CT alone and 81% (p = .06), 88% (p = .03), and 89% (p
> .25), respectively, for CT with FDG PET. Also, supplemental FDG PET imaging
improved observer confidence and accuracy in diagnosing recurrent neoplasm in
four (36%) of 11 patients who had undergone surgery or chemoradiation and in
diagnosing four (29%) of 14 extrahepatic sites that had potential metastases.
CONCLUSION: Diagnosis of malignancy in oncologic patients is significantly
improved when CT is supplemented with FDG PET. Combined imaging is particularly
helpful in the evaluation of potential recurrence in previously treated patients
and for diagnosing extrahepatic lesions that may be distant metastases.
PMID- 9763006
TI - MR lymphangiography in infants, children, and young adults.
AB - OBJECTIVE: Our objective was to offer a preliminary description of MR
lymphangiography; its uses and limitations; and its findings in infants,
children, and young adults. SUBJECTS AND METHODS: Twenty-nine patients underwent
32 MR lymphangiographic examinations for evaluation of vascular malformations,
other masses, soft-tissue swelling, gigantism, fluid accumulation, or pain. MR
lymphangiography was based on a heavily T2-weighted fast spin-echo sequence and a
maximum-intensity-projection algorithm. We assessed the axial and off-axial
lymphatic channels in conjunction with MR venography to help differentiate veins
from lymphatics. Correlation was made with published lymphangiograms and anatomic
diagrams to assist interpretation and (when available) with histologic specimens
(n = 11) for validation. RESULTS: Presumed lymphatic channels were seen
universally, although 14 examinations showed incomplete venous signal
suppression. Lymphatic channels appeared normal in eight children and in 20 of
the 21 asymptomatic contralateral limbs. Ten patients had an increased number and
size of off-axial channels, including seven children with large, diffuse low-flow
vascular malformations. Enlarged axial and off-axial channels were seen in five
patients, four of whom had Klippel-Trenaunay syndrome. Six patients, each with an
extensive hemangioendothelioma, Klippel-Trenaunay syndrome, Gorham syndrome, or
unilateral body edema, showed absence or interruption of axial channels.
CONCLUSION: MR lymphangiography appears to be a useful noninvasive technique to
study superficial and deep lymphatic channels in children with local or diffuse
vascular lesions or swelling of extremities. Its limitations notwithstanding, the
technique may offer further insight into the nature of vascular anomalies, may
direct therapy, and may predict prognosis.
PMID- 9763007
TI - Echodense spinal subarachnoid space in neonates with progressive ventricular
dilatation: a marker of noncommunicating hydrocephalus.
AB - OBJECTIVE: Our purpose was to evaluate the frequency and clinical significance of
echogenic debris in the spinal subarachnoid space of neonates at risk for
progressive ventricular dilatation. SUBJECTS AND METHODS: Spinal sonography was
performed on 15 neonates with severe intracranial hemorrhage (n = 10) or
bacterial meningitis (n = 5). Spinal sonography also was performed on 16 control
neonates. Images were analyzed for the presence and location of echogeric debris
within the thoracolumbar subarachnoid space. Lumbar punctures were performed on
all 31 neonates, and CSF was analyzed for cell count and protein content. Ten of
15 neonates required ventricular drainage procedures. RESULTS: Progressive
ventricular dilatation occurred in 11 of 15 neonates with intracranial hemorrhage
or meningitis. Echogenic debris was present in the thoracolumbar subarachnoid
space on spinal sonography in every neonate with progressive ventricular
dilatation compared with none of the 16 control neonates (p < .0001 by chi-square
analysis). In addition, the 11 neonates with echogenic subarachnoid space had
significantly higher protein and RBC contents in the lumbar CSF (p < .04).
CONCLUSION: Echogenic subarachnoid space revealed by sonography is associated
with progressive ventricular dilatation after severe intracranial hemorrhage or
bacterial meningitis and is caused by high protein and RBC contents in the
subarachnoid space. This finding may be helpful in identifying neonates who will
not benefit from serial lumbar punctures for treatment of hydrocephalus.
PMID- 9763008
TI - Cerebral 1H MR spectroscopy and neuropsychologic status of patients with hepatic
encephalopathy.
AB - OBJECTIVE: Our objective was to assess the metabolite levels (myo-inositol [ml],
choline [Cho], creatine [Cr], glutamate or glutamine [Glx], and N-acetyl-L
aspartate [NAA]) visible on 1H MR spectroscopy in patients with subclinical and
mild hepatic encephalopathy before and after liver transplantation and to
correlate these data with the results of neuropsychiatric tests and related
clinical findings. SUBJECTS AND METHODS: A stimulated-echo sequence was used to
localize a single voxel in the parietal region. Seventeen patients and 13 healthy
volunteers were investigated. Nine of the 17 patients also were investigated
after liver transplantation. A battery of neuropsychologic tests also was
administered to patients to assess frontal, memory, and motor functions. RESULTS:
Before liver transplantation, significant reductions in mI:Cr (51%) and Cho:Cr
(11%) and a significant increase in Glx:Cr (20%) were observed in patients
compared with the respective ratios in healthy subjects. Patients also were
significantly impaired on neuropsychologic tests measuring frontal and motor
performance, but not memory. Impairment on the frontal index showed a significant
correlation with mI:Cr levels; likewise, performance on the motor index showed a
significant correlation with serum ammonia levels before transplantation. MR
spectroscopy after liver transplantation showed changes in the metabolite ratios
compared with the pretransplantation status. Even though the Glx:Cr ratios
decreased after transplantation, the mI:Cr ratio remained lower than those of
healthy subjects. CONCLUSION: The relationship of changes in the metabolite
ratios recorded from a voxel in the posteromedial parietal lobe to the
neuropsychologic findings before and after liver transplantation is a major
finding.
PMID- 9763009
TI - Usefulness of CT and MR imaging in the diagnosis of acute Wernicke's
encephalopathy.
AB - OBJECTIVE: In this study, we analyzed the sensitivity and specificity of CT and
MR imaging in the diagnosis of acute Wernicke's's encephalopathy. SUBJECTS AND
METHODS: Three groups of subjects were studied: 15 patients with acute Wernicke's
encephalopathy; 15 asymptomatic alcoholics; and 15 control subjects. Studies
included clinical and laboratory examinations as well as CT and MR imaging of the
brain. RESULTS: On CT scans, two patients with Wernicke's encephalopathy (13%)
and no asymptomatic alcoholics showed low-density abnormalities in the
paraventricular regions of the thalamus (p = .2414). On MR imaging, increased T2
signal of paraventricular regions of the thalamus was observed in seven patients
(46%) with Wernicke's encephalopathy and one asymptomatic alcoholic (6%) (p <
.01), and increased T2 signal of periaqueductal regions of the midbrain in six
patients (40%) with Wernicke's encephalopathy and one asymptomatic alcoholic (6%)
(p < .05). However, no significant differences were observed in the prevalence of
mamillary body shrinkage between alcoholics with Wernicke's encephalopathy (six
[40%]) and asymptomatic chronic alcoholics (four [27%]). The sensitivity of MR
imaging in revealing evidence of this disease was 53% and the specificity, 93%.
CONCLUSION: MR imaging is useful in confirming the diagnosis of acute Wernicke's
encephalopathy. However, the absence of abnormalities on MR imaging does not
exclude this diagnosis. CT proved not useful in the diagnosis of Wernicke's
encephalopathy.
PMID- 9763010
TI - The hippocampus: normal anatomy and pathology.
AB - The hippocampus is a complex and fascinating region of the brain that has
enormous clinical significance. Specifically, small imaging abnormalities may
cause major symptoms. We believe that the detection of these lesions will be
improved if imaging clinicians have an organized reference that facilitates
identification of the cellular zones that comprise the hippocampus.
PMID- 9763011
TI - MR imaging in a patient with homocystinuria.
PMID- 9763012
TI - Helical CT for initial imaging of pulmonary embolus.
PMID- 9763013
TI - Circumscribed lesions seen at screening mammography.
PMID- 9763014
TI - Transvaginal sonography in postmenopausal women with bleeding.
PMID- 9763015
TI - More on standards of care.
PMID- 9763016
TI - More on informed consent.
PMID- 9763017
TI - Re: Chest radiography after placement of internal jugular central venous access
devices.
PMID- 9763018
TI - More on sonographic features in the differentiation of fibroadenoma and invasive
ductal carcinoma.
PMID- 9763019
TI - Aortic dissection versus penetrating aneurysm.
PMID- 9763020
TI - Heartburn redux.
PMID- 9763021
TI - Insignificance of small loculated pneumothoraces after core biopsies of
peripheral lung lesions using the Temno biopsy needle.
PMID- 9763022
TI - A rare cause of respiratory failure: Echinococcus of the pulmonary artery.
PMID- 9763023
TI - Disseminated Bartonella henselae (cat-scratch disease): appearance of multifocal
osteomyelitis with MR imaging.
PMID- 9763024
TI - Three-dimensional sonography in diagnosing trisomy 18.
PMID- 9763025
TI - Isolated uterine relapse in a child with acute lymphoblastic leukemia.
PMID- 9763026
TI - An unusual sonographic finding in Caroli's disease.
PMID- 9763027
TI - Frozen section of thyroid? Just say no.
PMID- 9763028
TI - Alpha-L-fucose: a potentially critical molecule in pathologic processes including
neoplasia.
AB - Alpha-L-fucose is a 6-carbon deoxyhexose that is commonly incorporated into human
glycoproteins and glycolipids. It is found at the terminal or preterminal
positions of many cell-surface oligosaccharide ligands that mediate cell
recognition and adhesion-signaling pathways. These include such normal events as
early embryologic development and blood group recognition and pathologic
processes including inflammation, infectious disease recognition, and neoplastic
progression. Fucosylated oligosaccharide ligands mediate cell-cell adhesion
through binding to cell-surface selectins (calcium-dependent binding proteins)
and calcium-dependent interactions with other cell-surface carbohydrate
counterligands. A number of fucose-containing "natural ligands" are common to
inflammatory and malignant cell processes. We review evidence that alpha-L-fucose
is critically important for cell-cell and cell-matrix adhesion in a variety of
normal and pathologic processes, particularly neoplasia. Current results suggest
that alpha-L-fucose provides the essential structure that enables carbohydrate
ligands to bind to selectins and to carbohydrate counterligands and thereby alter
cellular homeostasis.
PMID- 9763029
TI - Bcl-2 oncoprotein positivity and high MIB-1 (Ki-67) proliferative rate are
independent predictive markers for recurrence in prostate carcinoma.
AB - Predicting the clinical behavior of prostate carcinoma can be difficult; one
approach is to identify molecular prognostic markers. We evaluated proliferative
rate (MIB-1 antibody) and expression of bcl-2, p53, and retinoblastoma (pRB)
proteins, which have cell cycle-related functions, in 208 consecutive radical
prostatectomy specimens. Values were correlated with histopathologic parameters
(Gleason tumor score, tumor amount, capsule invasion, and involvement of surgical
margins, seminal vesicles, or lymph nodes) and with recurrence-free survival (4
year median follow-up). A high MIB-1 proliferative rate was associated with all
of the measured histopathologic parameters, p53 overexpression with tumor amount,
and pRB expression with positive lymph nodes. pRB and p53 expression levels were
not associated with differences in recurrence-free survival. A high MIB-1
proliferative rate and bcl-2 positivity were associated with increased
recurrence, both considered individually, and also independently and additively
when examined together and with the most predictive histopathologic factors
(Gleason tumor score and seminal vesicle involvement). MIB-1 proliferative rate
and bcl-2 positivity may prove to be useful markers for poor prognosis in
prostate carcinoma.
PMID- 9763030
TI - Histochemical analysis of mucous cells of congenital adenomatoid malformation of
the lung: insights into the carcinogenesis of pulmonary adenocarcinoma expressing
gastric mucins.
AB - Adenocarcinomas expressing gastric mucins often are accompanied by ectopic
gastric mucosa or pyloric metaplasia. We have previously described mucinous
bronchioloalveolar carcinoma (mucinous BAC) producing gastric mucins. In the lung
tissue, mucous cells seemingly similar to gastric mucous cells are present in
congenital adenomatoid malformation (CAM). We assessed 26 cases of CAM
morphologically and histochemically. Mucous cells were detected in 12 of 26
cases. These mucous cells displayed papillary growth in cystic spaces and
proliferated along alveolar walls. Mucous cells in the papillary, configuration
stained with galactose oxidase cold thionine Schiff reaction, and those in
indented portions stained with paradoxical concanavalin A stain in all 8 cases
and with pepsinogen II in 5 of 8 cases, which were available for histochemical
analysis. Pepsinogen I was negative. Mucous cells in CAM were identical to those
of pyloric mucosa and could be considered candidates for the origin of mucinous
BAC producing gastric mucins.
PMID- 9763032
TI - Four-color flow cytometric immunophenotypic determination of peripheral blood
CD4+ T-lymphocyte counts: a comparison of validity and cost-effectiveness with a
two-color method.
AB - The clinical usefulness of monitoring CD4+ T-lymphocyte counts in patients
infected with HIV is now well established. The need for accurate, rapid, and cost
effective methods for making these determinations is evident. Recent technologic
advances have allowed for the development of a system for the determination of
CD4+ T-lymphocyte counts by simultaneous 4-color flow cytometry. A new 4-color 2
tube flow cytometric method for analyzing CD4+ T-lymphocyte subsets in whole
blood was compared with a standard 2-color 5-tube method. The new method provides
results almost identical to those of the well-established 2-color method used in
our clinical laboratory. Statistical analyses indicate very low variability in
CD4+ counts between the 2 methods, strongly supporting the usefulness of this new
procedure. In addition, the 4-color procedure provides a 15% reduction in the
materials cost per test compared with the 2-color method, as well as a marked
reduction in the time expenditure of flow cytometry technologists.
PMID- 9763031
TI - Comparison of intraoperative cytology with frozen sections in the diagnosis of
thyroid lesions.
AB - We retrospectively studied the usefulness of intraoperative cytology (IOC) and
frozen section (FS) in the rapid diagnosis of 68 thyroid lesions. In 14 cases of
papillary thyroid carcinoma, IOC correctly diagnosed 13 cases, while FS correctly
diagnosed 11 cases. There was no significant difference in sensitivities, and
both methods had similar specificities. In 21 cases of colloid nodule, IOC was
slightly more sensitive than FS; IOC correctly diagnosed 16 cases, while FS
correctly diagnosed 15 cases. However, the specificity of IOC was only 71%, but
was 98% for FS. Of 17 follicular adenomas, FS diagnosed 16 as follicular
neoplasms and misdiagnosed only 1 as a colloid nodule. By contrast, IOC
misdiagnosed 9 follicular adenomas as colloid nodules, most of which were
macrofollicular variants with abundant colloid. Of 11 follicular carcinomas, FS
diagnosed all as follicular neoplasms, while IOC misdiagnosed 3 as colloid
nodules. While IOC is not as accurate as FS in the diagnosis of colloid nodules
and follicular neoplasms, it is highly sensitive and specific in the diagnoses of
papillary carcinoma and performance of the technique is rapid and easy. In an
intraoperative setting, IOC is a useful adjunct to FS in screening thyroid
nodules for the presence of papillary carcinoma.
PMID- 9763033
TI - Lymphoid lesions of the gastrointestinal tract: a histologic, immunophenotypic,
and genotypic analysis of 49 cases.
AB - The diagnosis of gastrointestinal (GI) lymphoid infiltrates can be challenging
when based only on conventional microscopic assessment. When marked cytologic
atypia is present, a diagnosis of malignant neoplasm is readily made; however,
the distinction between a low-grade malignant neoplasm and a reactive process is
much more difficult. If unfixed tissue is available, immunohistologic or
genotypic methods that are usually aimed at defining B-lymphocytic monotypism can
be applied. However, paraffin-embedded tissue has generally been deemed
unsuitable for these techniques. We assessed the value of a panel of
immunohistochemical stains and a seminested polymerase chain reaction (PCR) for
the analysis of lymphoid infiltrates in routinely processed GI biopsy specimens
from 49 archival cases, including morphologically benign, indeterminate, and
overtly malignant lesions. Clinical outcome was used as the retrospective
diagnostic standard; end points were death (of lymphomatous disease or otherwise)
and clinical evidence of lymphoma. According to light microscopic criteria, 19
cases were classified as benign, 17 as malignant, and 13 as atypical.
Immunophenotyping correctly identified 28 of 31 benign and 14 of 18 malignant
lesions (7 cases had an indeterminate immunoprofile). Genotypic analysis
correctly identified 12 of 18 malignant and 29 of 31 benign lesions, but spurious
monoclonal bands were produced by PCR amplification of 2 of the latter 31 cases.
No single technique exists for correct categorization of all paraffin-embedded
specimens of GI lymphoid infiltrates. We recommend a sequential approach to the
use of available diagnostic modalities.
PMID- 9763034
TI - A cutaneous agranular CD2- CD4+ CD56+ "lymphoma": report of two cases and review
of the literature.
AB - We report 2 cases of agranular CD2- CD4+ CD56+ non-Hodgkin lymphoma in which skin
seemed to be the primary site. A 21-year-old woman's initial symptom was a skin
nodule on the right cheek. She also had tumors in the nasopharynx, and the bone
marrow subsequently became involved. No lymphadenopathy was present. She
experienced complete remission after dose-intensified therapy with
cyclophosphamide, hydroxydaunomycin, vincristine [Oncovin], and prednisone
(CHOP), but the disease relapsed in the central nervous system 6 months later. An
81-year-old man experienced an 11-month history of skin nodules in the left
forearm. On admission, he had a bone marrow infiltration of lymphoma cells. He
died of pneumonia during chemotherapy. The malignant cells of the 2 patients had
similar morphologic features, with a monocytoid nucleus and no cytoplasmic
granules. The cells in both cases showed a unique phenotype: CD2-, CD3-, CD4+,
CD8-, CD13-, CD14-, CD34-, CD16-, CD56+, CD57-, HLA-DR-positive. Staining for
peroxidase and alpha-naphthyl butyrate esterase was negative. The T-cell receptor
beta, gamma, delta, IgH, kappa, lambda genes were of germ line configurations.
The DNA of Epstein-Barr virus was not detected from the bone marrow cells by
polymerase chain reaction. Only 3 other cases with similar phenotypes have been
reported; all had skin lesions. Although the origin of these cells remains
unknown, we propose that this is a distinct clinicopathologic entity.
PMID- 9763035
TI - Cocaine and cocaethylene binding to human milk.
AB - The binding of cocaine and its ethyl analog, cocaethylene, to human milk was
studied using equilibrium dialysis at 4 degrees C. For cocaine, a low-affinity,
high-capacity binder was noted (equilibrium constant of association, Ka, 3.12 x
10(3) L/mol; concentration of binding sites, B0, 3.85 x 10(-4) mol/L), as well as
a very low affinity, high-capacity binder (Ka, 7.54 x 10(2) L/mol; B0, 1.42 x 10(
3) mol/L). For cocaethylene, 2 low-affinity, high-capacity binders were
suggested: a stronger (Ka, 3.79 x 10(3) L/mol; B0, 3.27 x 10(-4) mol/L) and a
weaker (Ka, 1.84 x 10(3) L/mol; B0, 8.91 x 10(-4) mol/L) binder The low-affinity,
high-capacity binder for cocaine and cocaethylene seems to be albumin, while the
weaker nonspecific binding may be due to lipids. Up to 55% of cocaine and up to
61% of cocaethylene were bound to milk; such binding, coupled with the lower pH
of milk (6.9) relative to that of serum (7.4), may enhance the mammary secretion
of these 2 basic drugs, having important consequences for the nursing infant.
PMID- 9763036
TI - Evaluation of a rapid homogeneous method for direct measurement of high-density
lipoprotein cholesterol.
AB - We evaluated the performance of a direct Liquid N-geneous HDL-C assay (N-HDL;
Genzyme Diagnostics, Cambridge, Mass) and compared it with a Centers for Disease
Control and Prevention (CDC) modified reference procedure (M-REF) and
phosphotungstic acid (PTA) precipitation method in patients with
normotriglyceridemia (triglyceride level, <400 mg/dL) and hypertriglyceridemia
(triglyceride level, > or =400 mg/dL). Excellent intra-assay and interassay
coefficients of variation were obtained (<2.0%) using the N-HDL assay. The N-HDL
and PTA assays correlated well with M-REF in normotriglyceridemic samples. In
hypertriglyceridemic samples, however, the N-HDL method exhibited better
correlation with M-REF than the PTA assay. In addition, compared with M-REF, the
mean absolute percentage bias of N-HDL was lower than the PTA assay in
normotriglyceridemic (4.9% vs 5.8%) and hypertriglyceridemic (5.4% vs 12.9%)
samples. Hemolysis, ascorbic acid, and bilirubin did not interfere with the N-HDL
assay. On the basis of these findings, the N-HDL assay compares favorably with
the modified CDC reference method and seems superior to the PTA assay. It also
has the advantage of being suited for complete automation and, thus, would prove
useful in large clinical laboratories.
PMID- 9763037
TI - Prospective study of serum protein capillary zone electrophoresis and
immunotyping of monoclonal proteins by immunosubtraction.
AB - Capillary zone electrophoresis and immune adsorption were evaluated for
identification of serum protein abnormalities and immunotyping of monoclonal
proteins. A 7-capillary, electrophoresis instrument and solid phase
immunosubtraction reagents were used in a prospective study of 1,518 patients.
Serum protein electrophoresis was performed by agarose gel electrophoresis and
capillary electrophoresis and interpreted with regard to identification of
abnormalities consistent with monoclonal gammopathies. The agarose gel
electrophoresis had a sensitivity and specificity of 91% and 99%, respectively,
whereas capillary electrophoresis gave results of 95% and 99%. Immunotyping of
the monoclonal proteins was performed by immunofixation and immunosubtraction.
Capillary electrophoresis was more sensitive than agarose gel electrophoresis for
the identification of monoclonal proteins in serum. In addition, the
immunosubtraction method seems technically simpler and more automated than
immunofixation and represents a useful additional approach for immunotyping
monoclonal proteins.
PMID- 9763038
TI - A conflict of interest?
PMID- 9763039
TI - Human sensitivity vs automation.
PMID- 9763040
TI - The blood supply in 1984.
PMID- 9763041
TI - Routine ultrasound is the method of choice for dating pregnancy.
PMID- 9763042
TI - Misoprostol for all?
PMID- 9763043
TI - Continuing medical education: an opportunity for bringing about change in
clinical practice.
PMID- 9763044
TI - The reproductive system after childhood cancer.
PMID- 9763045
TI - Folates in the periconceptional period: are women getting enough?
AB - OBJECTIVE: To examine the prevalence of folic acid supplementation prior to
conception and in the first trimester of pregnancy, and to identify
sociodemographic variables associated with the use of supplements. DESIGN:
Observational study. SETTING: District general hospital in the south in England.
POPULATION: Nine hundred and sixty-three randomly selected pregnant nulliparous
caucasian women recruited from May 1994 to February 1996 inclusive. METHODS:
Questionnaire administered at approximately 16 weeks gestation. MAIN OUTCOME
MEASURES: Intakes of supplemental folic acid before conception and during
pregnancy. RESULTS: 31.5% (303/963) (95% CI 28.5-34.4) of pregnant women reported
using supplements containing folic acid prior to conception. The proportion using
pre-conceptional folic acid increased by approximately 1% per month during the 22
months of the study. 38.1% (367/962) (35 1 to 41.2) of women began taking folic
acid only after the confirmation of pregnancy, and this proportion appeared
constant over time. Young age, smoking and low educational attainment were
statistically significant predictors of failure to use folic acid both before and
during pregnancy. CONCLUSIONS: Use of folic acid before conception in nulliparous
women is much higher than the 2% to 3% reported in earlier studies of all
pregnant women, and appears to be increasing. However, many women still only
begin taking folic acid after conception, despite current health education
strategies. New approaches, focusing on women who are currently least likely to
take folic acid those who are young, are of low educational backgrounds, and are
smokers - may now be required. Given the inevitably of unplanned pregnancies,
efforts must also be made to increase the currently static uptake of folic acid
immediately after the confirmation of pregnancy.
PMID- 9763046
TI - Choosing options for ultrasound screening in pregnancy and comparing cost
effectiveness: a decision analysis approach.
AB - OBJECTIVE: To compare the cost effectiveness of different programmes of routine
antenatal ultrasound screening to detect four key fetal anomalies: serious
cardiac anomalies, spina bifida, Down's syndrome and lethal anomalies, using
existing evidence. DESIGN: Decision analysis was used based on the best data
currently available, including expert opinion from the Royal College of
Obstetricians and Gynaecologists, Working Party and secondary data from the
literature, to predict the likely outcomes in terms of malformations detected by
each screening programme. SETTING: Results applicable in clinics, hospitals or GP
practices delivering antenatal screening. MAIN OUTCOME MEASURE: The number of
cases with a 'target' malformation correctly detected antenatally. RESULTS: There
was substantial overlap between the cost ranges of each screening programme
demonstrating considerable uncertainty about the relative economic efficiency of
alternative programmes for ultrasound screening. The cheapest, but not the most
effective, screening programme consisted of one second trimester ultrasound scan.
The cost per target anomaly detected (cost effectiveness) for this programme was
in the range 5,000 pound silver-109,000, pound silver but in any 1000 women it
will also fail to detect between 3.6 and 4.7 target anomalies. CONCLUSIONS: The
range of uncertainty in the costs did not allow selection of any one programme as
a clear choice for NHS purchasers. The results suggested that the overall
allocation of resources for routine ultrasound screening in the UK is not
currently economically efficient, but that certain scenarios for ultrasound
screening are potentially within the range of cost effectiveness reached by
other, possibly competing, screening programmes. The model highlighted the
weakness of available evidence and demonstrated the need for more information
both about current practice and costs.
PMID- 9763048
TI - Partogram action line study: a randomised trial.
AB - OBJECTIVE: To assess the effect of three different partograms on caesarean
section and maternal satisfaction. DESIGN: Prospective randomised clinical trial.
SETTING: Regional teaching hospital in North West of England. PARTICIPANTS: Nine
hundred and twenty-eight primigravid women with uncomplicated pregnancies who
presented in spontaneous labour at term. INTERVENTIONS: The women were randomised
to have their progress of labour recorded on a partogram with an action line 2, 3
or 4 hours to the right of the alert line. If the progress reached the action
line, a diagnosis of prolonged labour was made. Prolonged labour was managed
according to the standard ward protocol. MAIN OUTCOME MEASURES: Primary:
Caesarean section rate and maternal satisfaction; secondary: need for
augmentation, duration of labour, analgesia, cord blood gas analysis, postpartum
haemorrhage, number of vaginal examinations, Apgar score and admission to special
care baby unit. RESULTS: Caesarean section rate was lowest when labour was
managed using a partogram with a 4-hour action line. The difference between the 3
and 4-hour partograms was statistically significant (OR 1 8, 95% CI 1.1-3.2),
but the difference between 2 and 4 hours was not (OR 1.4, 95% CI 0.8-2.4). The
women in the 2-hour arm were more satisfied with their labour when compared to
the women in the 3-hour (P < 00001) and 4-hour (P <00001) arm. CONCLUSION: Our
data suggest that women prefer active management of labour. It is possible that
partograms which favour earlier intervention are associated with higher caesarean
section rate. As the evidence on which to base the choice of partograms remains
inconclusive further research is required.
PMID- 9763047
TI - A randomised placebo controlled trial of oral misoprostol in the third stage of
labour.
AB - OBJECTIVE: To compare oral misoprostol 400 microg with placebo in the routine
management of the third stage of labour. DESIGN: A double-blind placebo
controlled trial. Setting The labour ward of an academic hospital in
Johannesburg, South Africa with 7000 deliveries per annum. PARTICIPANTS: Low-risk
women expected to deliver vaginally. METHODS: Women in labour were randomly
allocated to receive either misoprostol 400 microg orally or placebo after the
birth. Conventional oxytocics were given immediately if blood loss was thought to
be more than usual. Postpartum blood loss in the first hour was measured by
collection in a special flat plastic bedpan. Side effects were recorded. MAIN
OUTCOME MEASURES: Measured blood loss > or = 1000 ml within the first hour after
birth. Use of additional oxytocics. RESULTS: The groups were well matched.
Measured blood loss > or = 1000 ml occurred in 15/250 (6%) after misoprostol and
23/250 (9%) after placebo (relative risk 0.65; 95% confidence interval 0.35
1.22). The difference may have been reduced by the greater use of conventional
oxytocics in the placebo group, which was statistically significant for
intravenous oxytocin infusion (2.8% vs 8.4%, relative risk 0.33, 95% confidence
interval 0.14-0.77). Shivering was more common in the misoprostol group (19% vs
5%, relative risk 3.69; 95% confidence interval 2.05-6.64). CONCLUSIONS:
Shivering has been shown in this study to be a specific side effect of
misoprostol administered orally in the puerperium. No serious side effects were
noted. Misoprostol shows promise as a method of preventing postpartum
haemorrhage. Because of the potential benefits for childbearing women,
particularly those in developing countries, further research to determine its
effects with greater certainty should be expedited.
PMID- 9763049
TI - Maternal intensive care and near-miss mortality in obstetrics.
AB - OBJECTIVE: To determine the level of near-miss maternal mortality and morbidity
due to severe obstetrical complications or maternal disease in a tertiary
maternity hospital. DESIGN: Retrospective review. SETTING: A free-standing
maternity hospital delivering 5500 infants per year. METHODS: The information
coded in the perinatal database concerning women who had required transfer for
critical care to a general hospital was reviewed for the 14 year period 1980 to
1993. The complications necessitating transfer and the specialised consultants
and services required were noted. RESULTS: Over 14 years there were 76,119 women
delivered with two maternal deaths (2.6/100,000). Fifty-five women required
transfer for critical care (0.7/1000). The main reasons for transfer were
hypertensive disease (25%), haemorrhage (22%) and sepsis (15%). Transfer to an
intensive care unit was required by 80%, and the remainder were transferred to
specialised medical or surgical units. Twenty different specialist groups were
consulted. The 55 patients spent 280 days in critical care and 464 days hospital
after-care (mean 13 days, range 3-92). CONCLUSION: A review of near-miss maternal
mortality helps delineate the continuing threats to maternal health and the type
of support services most commonly required.
PMID- 9763050
TI - Severe acute maternal morbidity: a pilot study of a definition for a near-miss.
AB - OBJECTIVE: To test the application of a clinical definition of severe acute
maternal morbidity. DESIGN: A one-year prospective descriptive multi-centre
study. SETTING: Kalafong and Pretoria Academic hospitals, catering for the
delivery of indigent women in the Pretoria Health Region. METHODS: A 'near-miss'
describes a patient with an acute organ system dysfunction, which if not treated
appropriately, could result in death. The case notes of women fitting this
definition and all maternal deaths were analysed and compared. OUTCOME MEASURE:
Determine the primary obstetric factors and the organ systems that failed.
Identification of episodes of sub-standard care and missed opportunities. Results
One hundred and forty-seven near misses and 30 maternal deaths were identified.
The commonest reasons for a near-miss were: emergency hysterectomy in 42 women
(29%); severe hypotension in 40 (27%); and pulmonary oedema in 24 (16%). The most
common initiating obstetric conditions were hypertension in 38 women (26%);
haemorrhage in 38 (26%); and abortion or puerperal sepsis in 29 (20%). The
primary obstetric factors amongst the maternal deaths were: hypertension (33%);
sepsis (27%); and maternal medical diseases (17%) in 10, 8 and 5 women
respectively. Sub-standard care was identified in 82 cases. Breakdown in the
health care administration was identified in 33, and patient-orientated missed
opportunities on 34 occasions. CONCLUSION: The definition of severe acute
maternal morbidity identified nearly five times as many cases as maternal death.
This definition allows for an effective audit system of maternal care because it
is clinically based, the definition is robust and the cases identified reflect
the pattern of maternal death.
PMID- 9763052
TI - The impact of rubella immunisation on the incidence of rubella, congenital
rubella syndrome and rubella-related terminations of pregnancy in South
Australia.
AB - OBJECTIVES: To describe the impact of rubella immunisation on the incidence of
rubella, congenital rubella syndrome and rubella-related terminations of
pregnancy in South Australia, and to identify factors associated with a re
emerging problem. DESIGN AND METHODS: A population-based descriptive study using
data from South Australian notifications of disease, births and terminations of
pregnancy, the rubella immunisation programme, antenatal rubella antibody
screening and paediatric hospital case records. SETTING: South Australia
(population 1.48 million people; 20,000 births per year). MAIN OUTCOME MEASURES:
Incidence of rubella (age-sex specific), congenital rubella syndrome and rubella
related terminations of pregnancy; antenatal rubella sero-positive rates; rubella
immunisation uptake rates. RESULTS: Rubella notification rates in 1990-1996 were
significantly higher for males than females for ages 15-34 years. There were five
cases of congenital rubella syndrome notified in 1980-1996 compared with at least
20 confirmed or compatible cases in 1965-1979. Rubella-related terminations of
pregnancy are now rare, with the last termination for maternal rubella being in
1993. The antenatal rubella sero-positive rate in 1995 was 96.7%, but was
significantly lower among Asian women born overseas (78.6% among those 30 years
or older). Vaccination uptake rates in schoolgirls decreased between 1990 and
1994 (91.2% to 86.9%). CONCLUSIONS: Since the introduction of rubella
immunisation, the incidence of rubella infection among women of reproductive age,
and of rubella-related terminations, has fallen. Congenital rubella syndrome has
not been notified since 1990 but its risk persists with a recent increase in
rubella notifications, a fall in school immunisation rates, a relatively low
antenatal sero-positive rate among older Asian women born overseas and the trend
towards giving birth at older ages. Effective immunisation programmes must be
maintained, particularly in schools and for young children and migrant women.
PMID- 9763051
TI - Does an early postnatal check-up improve maternal health: results from a
randomised trial in Australian general practice.
AB - OBJECTIVES: To investigate whether a visit to a general practitioner one week
after discharge results in less depression, increased breastfeeding rates,
improved patient wellbeing, fewer physical problems and greater satisfaction with
general practice care than the traditional six week postnatal check-up. DESIGN: A
randomised controlled trial. SETTING: Rural and metropolitan Victoria, Australia.
Population Women giving birth at one rural and one metropolitan hospital between
February and December 1995 inclusive. METHODS: All women received a letter and
appointment date to see a general practitioner for a check-up: the intervention
group for one week after hospital discharge, the control group for six weeks
after birth. A mail-out survey was conducted at three and six months after birth,
including Edinburgh Postnatal Depression Scale and Short Form 36. RESULTS:
1017/1407 (72.3%) women giving birth at participating hospitals were eligible for
the trial: 683 (67.2%) gave informed consent. The average response rate to postal
follow up at three and six months was 67.5%. No significant differences were
found between the groups in: Edinburgh Postnatal Depression and Short Form 36
scores; number of problems; breastfeeding rates; or satisfaction with general
practitioner care. Women in the intervention group were less likely to attend for
their check-up (76.4% vs 88.4%; P = 0.001), more likely to discuss labour and
birth at their check-up (OR= 1.77, 95% CI 1.17-2.68), less likely to have a
vaginal examination (OR = 0.51; 95%, CI 0.34-0.77) or pap smear (OR = 0.34; 95%
CI = 0.22-0.52) at their check; more likely to report difficulties with low milk
supply (OR= 1.72; 95% CI = 1.12-2.66) and adjusting to the demands of a new baby
(OR = 1.76; 95% CI 1.13 2.74), more likely to talk to a general practitioner
about their baby (68.2% vs 58.0%; P=0.02) and less likely to consult a hospital
doctor about their baby (7.3% vs 14.0%, P = 0.02). CONCLUSIONS: To make
clinically important improvements in maternal health more is required than early
postnatal review.
PMID- 9763053
TI - Neonatal mortality amongst Scottish preterm singleton births (1985-1994).
AB - OBJECTIVE: To provide a valid estimate of singleton neonatal mortality based on
birthweight and gestational age at delivery. DESIGN: Record linkage of maternity
data and neonatal mortality data. SETTING: Scotland, UK. POPULATION: All
singleton preterm deliveries from 24 to 36 weeks inclusive between 1985 and 1994.
MAIN OUTCOME MEASURE: Neonatal death. RESULTS: There were 625,646 liveborn
singleton deliveries over the study period, of which 33,912 were preterm (5.4%).
The overall neonatal mortality in the preterm group was 41/1000 and the data have
been presented by both gestational age and birthweight. The neonatal mortality
rate fell with advancing gestation from 795/1000 live births at 24 weeks to
9/1000 live births at 36 weeks and was higher at the extremes of birthweight for
a given gestational age. There was a significant increase in the proportion of
babies delivered iatrogenically over the study period (chi test for trend P <
0.001). CONCLUSION: This is the largest recent series to consider neonatal
mortality using both birthweight and gestational age. These figures will be of
use in obstetric management when elective preterm delivery is considered, and for
providing prognostic guidance following preterm delivery.
PMID- 9763054
TI - Preterm and term births of small for gestational age infants: a population-based
study of risk factors among nulliparous women.
AB - OBJECTIVE: To study risk factors for small for gestational age (SGA) infants by
gestational age among nulliparous women and to estimate mortality rates among SGA
and appropriate-for-gestational-age (AGA) infants by gestational age. DESIGN: A
population-based study from the Swedish Medical Birth Register. Setting Sweden
1992 1993. POPULATION: Liveborn singleton infants to nulliparous women (n =
96,662). MAIN OUTCOME MEASURES: Crude and adjusted odds ratios of risk factors
for SGA by gestational age. Rates of neonatal and postneonatal mortality.
RESULTS: Older maternal age (> or = 30 years) was foremost associated with
increased risks of very and moderately preterm SGA (> or = 32 weeks and 33-36
weeks, respectively), but also with term SGA (> or = 37 weeks). Risks of SGA
increased with decreasing maternal height at all gestational ages. Smoking
increased the risks of moderately preterm and term SGA. Short maternal education
increased the risk of preterm SGA and low pre-pregnancy body mass index slightly
increased the risk of term SGA. Pre-eclampsia and essential hypertension foremost
increased the risk of very preterm SGA (OR = 40.5 and 32.4, respectively) and
moderately preterm SGA (OR = 17.4 and 10.6, respectively), but also increased the
risk of term SGA. Neonatal and postneonatal mortality rates of SGA infants were
substantially influenced by gestational age, and mortality rates were
consistently higher among preterm SGA infants compared with AGA infants.
CONCLUSIONS: Risk factors for SGA and mortality rates among SGA infants vary by
gestational age. A subdivision of risk factors by gestational age adds knowledge,
particularly about risks of preterm SGA, where the highest rates of mortality
were observed.
PMID- 9763055
TI - Is cystic ovarian endometriosis an asymmetric disease?
AB - OBJECTIVE: To investigate whether asymmetry exists in the left- and right-handed
distribution of ovarian cystic lesions in a large series of women with
endometriosis. DESIGN: Retrospective evaluation of a case series. SETTING:
Tertiary care and referral academic centre for the study and treatment of
endometriosis. POPULATION: A total of 1054 consecutive women undergoing first
line surgical treatment for endometriosis in an eight-year period. METHODS: Data
were collected on indication for the intervention, age at surgery, parity and
disease stage as well as side and size of ovarian endometriomas. MAIN OUTCOME
MEASURE: Frequency of left- and right-sided ovarian endometriomas. RESULTS:
Histologically confirmed endometriotic ovarian cysts were present in 561 women,
which were on the left side in 255 instances, on the right in 148, and bilateral
in 158. In the patients with unilateral endometriomas, the observed proportion of
left cysts (255/403, 63%; 95% confidence interval, 58% to 68%) was significantly
different from the expected proportion of 50%, (chi2(1), 28.41, P<0.001).
Including also the bilateral endometriotic cysts gave a total of 413/719 (57%)
left-sided and 306/719 right-sided endometriomas. The magnitude of these
proportions did not vary appreciably during the eight years considered. The
difference in proportion of left- and right-sided endometriotic cysts was
virtually similar in subgroups of women with different indications for surgery.
Cyst side was not related to age, parity or cyst diameter. CONCLUSIONS: The
finding of a lateral asymmetry in the occurrence of ovarian endometriotic cysts
is compatible with the anatomical differences of the left and right hemipelvis
and supports the menstrual reflux theory.
PMID- 9763057
TI - Vaginal misoprostol alone is effective in the treatment of missed abortion.
PMID- 9763056
TI - Do routine antibiotics after loop diathermy excision reduce morbidity?
AB - OBJECTIVE: To evaluate whether routinely giving an antibiotic after loop
diathermy excision of the cervical transformation zone reduced post-operative
vaginal loss. DESIGN: Prospective, randomised, double-blind placebo controlled
parallel study. PARTICIPANTS: Five hundred women undergoing loop diathermy
excision in a colposcopy clinic. INTERVENTION: Administration of either ofloxacin
400 mg (2x200 mg) once daily for 5 days or an identical placebo. MAIN OUTCOME
MEASURE: Vaginal loss, assessed using a pictorial chart. RESULTS: No significant
difference in post-operative vaginal loss was found. CONCLUSION: Routine
antibiotic prophylaxis after loop diathermy excision is not justified.
PMID- 9763058
TI - Pregnancy and homozygous beta thalassaemia major.
AB - Nine pregnant women with homozygous beta-thalassaemia major followed a strict
transfusion regimen to maintain their haemoglobin level > 10 g/dl. One pregnancy
was terminated because of concern about desferrioxamine teratogenicity and
another ended in miscarriage at 11 weeks. All other women were delivered by
elective caesarean section between 37 and 38 weeks. There were no obstetric
complications or perinatal deaths.
PMID- 9763059
TI - Influence of chemotherapy for gestational trophoblastic disease on subsequent
pregnancy outcome.
AB - The aim of this study was to determine the influence of cytotoxic chemotherapy on
subsequent reproductive performance. Details of post-treatment reproductive
intent and outcome were requested from 1211 survivors registered at The Charing
Cross Hospital gestational trophoblastic disease centre; a response rate of 96%
was achieved. Seven hundred and twenty-eight women had tried to become pregnant;
607 reported at least one live birth, 73 conceived but had not registered a live
birth, and 48 did not conceive. No differences were apparent between the 392
women who received methotrexate as single agent chemotherapy and the 336 treated
with multi-agent chemotherapy. Women who had registered a live birth were younger
(P < 0.0001) and the duration of follow up was significantly less among those who
did not achieve pregnancy at all (P < 0.0003). A higher than expected rate of
caesarean section and stillbirth was recorded. The chemotherapy protocols used by
this unit have minimal impact on the subsequent ability to reproduce.
PMID- 9763060
TI - Vaginal delivery following combined pelvic renal and pancreatic transplant.
PMID- 9763061
TI - Retrievable inferior vena cava filter for thrombolic disease in pregnancy.
PMID- 9763062
TI - Retrievable inferior vena cava filter for thrombolic disease in pregnancy.
PMID- 9763063
TI - Routine ultrasound dating has not been shown to be more accurate than the
calendar method.
PMID- 9763064
TI - A study of the quality of perinatal autopsy in the former Northern region.
PMID- 9763065
TI - Magnesium sulphate: a review of clinical pharmacology applied to obstetrics.
PMID- 9763066
TI - Magnesium sulphate: a review of clinical pharmacology applied to obstetrics.
PMID- 9763067
TI - Renal dysplasia: the risks and consequences of leaving dysplastic tissue in situ.
PMID- 9763068
TI - Early experience with intraoperative cavernous nerve stimulation with penile
tumescence monitoring to improve nerve sparing during radical prostatectomy.
AB - OBJECTIVES: To determine if intraoperative stimulation of the cavernous nerves
while monitoring changes in penile tumescence to map the course of these nerves
would result in an improvement in nerve sparing and erectile function after
radical prostatectomy. METHODS: Patients were eligible for this pilot study if
they were undergoing a radical prostatectomy and were candidates for a nerve
sparing approach. Erectile function was assessed by patient self-reporting and
questionnaire before surgery and by patient self-reporting periodically 12 months
after surgery. A cavernous nerve stimulator and tumescence-monitoring device was
used during radical prostatectomy to identify the course of the cavernous nerves
and guide the surgeon in avoiding nerve damage. Patients were monitored for any
evidence of complications and/or adverse events for 1 year from time of surgery.
RESULTS: Twenty-six patients were recruited to the trial. Nerve stimulation and
tumescence monitoring was performed in 23 patients. Twenty-one of 23 patients
demonstrated a tumescence response to intraoperative nerve stimulation. Nineteen
of 21 patients reported erectile function preoperatively. Seventeen (89%) of 19
patients demonstrated a tumescence response during surgery. Sixteen (94%) of the
17 patients who demonstrated a response to nerve stimulation and for whom the
surgery was guided by the tumescence response reported the ability to have
erections after surgery. No side effects due to the use of the device were
reported. Only 3 (12%) of 25 patients had positive margins confined to the
lateral margin and/or apex whose modifications associated with nerve sparing
could conceivably have altered margin status. CONCLUSIONS: These clinical data
suggest that an intraoperative tumescence response to cavernous nerve stimulation
may guide the surgeon in preserving cavernous nerves and improving erectile
function after radical prostatectomy.
PMID- 9763069
TI - Laparoscopic renal cryoablation: initial clinical series.
AB - OBJECTIVES: To present the technique and short-term results of retroperitoneal
laparoscopic renal cryoablation. METHODS: Ten patients underwent laparoscopic
renal cryoablation of 11 exophytic renal tumors ranging in size from 1.5 to 3 cm
identified on computed tomography. Tumors were located at the upper (3), middle
(5), or lower (3) pole of the kidney. Three patients had a solitary kidney. A 3
port retroperitoneal laparoscopic approach was used to create renal cryolesions.
Puncture cryoablation was performed with a 4.8-mm cryoprobe. Real-time,
endoscopic, steerable, color Doppler ultrasound was used to monitor the evolving
cryolesion. All patients have completed a minimum follow-up of 3 months (mean
5.5, range 3 to 9). RESULTS: Cryoablation was technically successful in all 10
patients (11 tumors). Under ultrasound guidance, the ice ball was intentionally
created up to 1 cm beyond the tumor edge with the aim of achieving negative
margins. Mean surgical time was 2.4 hours, cryoablation (double freeze-thaw) time
12.9 minutes, cryoprobe tip temperature -186 degrees C, and blood loss 75 mL.
Systemic temperature remained unaltered. Hospital stay was less than 23 hours in
9 of 10 patients. Follow-up magnetic resonance imaging at 1 day and 1, 2, and 3
months identified the punched-out, nonenhancing, spontaneously resorbing, renal
cryolesion. Follow-up biopsies of the cryoablated tumor site were negative for
cancer in the 3 patients who have undergone the biopsy. CONCLUSIONS: The initial
series of laparoscopic renal cryoablation is presented. The retroperitoneoscopic
approach, by avoiding the peritoneal cavity, minimizes the chances of the bowel
coming in contact with the evolving cryolesion, and the potential sequelae
thereof. Laparoscopic renal cryoablation is currently developmental and long-term
data are awaited. Nevertheless, it is potentially an attractive addition to
available nephron-sparing surgical techniques.
PMID- 9763070
TI - Single-dose oral ciprofloxacin versus placebo for prophylaxis during transrectal
prostate biopsy.
AB - OBJECTIVES: To determine whether antimicrobial prophylaxis could prevent
infections after transrectal needle biopsy of the prostate using automated biopsy
devices. METHODS: We conducted a prospective, randomized, double-blind,
multicenter trial in which a total of 537 patients received either oral
ciprofloxacin 500 mg or placebo before transrectal needle biopsy of the prostate.
Repeated urine cultures and urinalysis were obtained at 2 to 6 days after biopsy
and 9 to 15 days after biopsy. The primary determinant of efficacy was
bacteriologic response (bacteriuria [more than 10(4) colony-forming units
(CFU)/mL] versus no bacteriuria) at the 9- to 15-day follow-up evaluation.
RESULTS: Two hundred twenty-seven (84%) of 269 ciprofloxacin patients and 230
(86%) of 268 placebo patients were valid for efficacy analysis in which a mean of
four biopsies was performed. Six ciprofloxacin-treated (3%) and 19 placebo
treated (8%) patients had bacteriuria (more than 10(4) CFU/mL) after the
procedure (P = 0.009). Six ciprofloxacin recipients (3%) and 12 placebo
recipients (5%) had clinical signs and symptoms of a urinary tract infection
(UTI) (P = 0.15). In addition, no ciprofloxacin-treated patients compared with 4
placebo-treated patients (2%) were admitted to the hospital for febrile UTI after
the procedure. Ciprofloxacin reduced the expected net costs of treating
infectious complications after biopsy by $23 per patient for an overall annual
savings of $68,195 in the five study groups when compared with placebo.
CONCLUSIONS: Single-dose oral ciprofloxacin reduced bacteriuria after biopsy
compared with placebo in patients undergoing transrectal prostatic biopsy and
provided an economic advantage. In addition, this study establishes the actual
rate of bacteriuria after transrectal needle biopsy of the prostate without
antibiotic prophylaxis to be 8% with a clinical rate of UTI of 5% and a
hospitalization rate of 2%.
PMID- 9763071
TI - Laser therapy of squamous cell dysplasia and carcinoma of the penis.
AB - OBJECTIVES: To analyze the influence of etiologic factors and practical issues
regarding the merits, limitations, and long-term results of aggressive laser
treatment of premalignant and malignant squamous cell lesions of the penis.
METHODS: Preparation of genital skin with 5% acetic acid and mapping biopsies of
lesions and the surrounding field-of-change were performed in 52 men evaluated
and subsequently treated with laser during a 10-year period. Most men (81%) were
or had been smokers, and many (46%) had female sexual partners infected with
human papillomavirus. Carbon dioxide laser was used for low-stage lesions;
potassium-titanylphosphate/532 or neodymium:yttrium-aluminum-garnet laser was
used for more histologically advanced lesions. Not only the lesions but also the
entire human papillomavirus-induced field-of-change was treated. Circumcision was
performed simultaneously in 28 previously uncircumcised patients. RESULTS: All
lesions demonstrated aceto-whitening and histologic changes of human
papillomavirus infection. Human papillomavirus DNA was detected in 93.5% of the
specimens from 31 patients studied. Of the 52 patients, 22 (42%) had dysplastic
premalignant penile intraepithelial neoplasia, and the remaining 30 (58%) had
squamous cell carcinoma. Forty-four patients were available for follow-up from 12
to 117 months (average 58). Overall, 5 patients (11.4%) experienced a recurrence:
3 were successfully re-treated with laser, and 2 patients underwent partial
penectomy, 1 of whom with squamous cell carcinoma Stage T2 died of metastatic
disease. CONCLUSIONS: Aggressive laser therapy of the visible lesions and of the
entire dysplastic premalignant field-of-change produces excellent cosmetic
results. The entire penis and, therefore, its full sexual functional potential
are preserved. The low rate of local recurrence over the long term in all but
deeply invasive (T2) lesions compares favorably with the outcome of other, more
conventional therapies. Irrespective of therapeutic approach, close and long-term
surveillance of all patients and counseling for their sexual partners are
mandatory.
PMID- 9763073
TI - Detection of adrenal and retroperitoneal masses in a general health examination
system.
AB - OBJECTIVES: To investigate the detection rate of adrenal and retroperitoneal
masses other than kidney diseases in a general health examination system.
METHODS: From May 1991 through February 1996, 41,357 subjects participated in the
general health examination system in our hospital. Approximately 80% of
participants were 40 to 59 years old. For all participants, transabdominal
ultrasound (US) was performed by five expert examiners using an Aloka SSD-650
with a 3.5-MHz convex-type transducer. When US revealed abnormal lesions on the
adrenal gland and in the retroperitoneal space, we recommended that participants
be examined with computed tomography (CT), with a slice width of 5 mm. RESULTS:
Forty-three participants (0.1%) had abnormal findings on US. Of the 28 of those
who underwent CT examination to confirm the lesions, 12 had adrenal and
retroperitoneal masses. The detection rate was 0.029% of total participants and
42.9% of those who underwent CT examination. Clinical diagnoses were primary
aldosteronism (1), preclinical Cushing syndrome (2), nonfunctioning
adrenocortical tumor (5), pheochromocytoma (1), ganglioneuroma (1), adrenal cyst
(1), and retroperitoneal neurinoma (1). False-positive results were dominant on
the left side of the body (right 3, left 13). A deformed or accessory spleen (3),
a cyst on the upper pole of the kidney (2), bowel air (2), and a pancreatic cyst
(1) were misdiagnosed as adrenal lesions on US. CONCLUSIONS: The low detection
rate of adrenal and retroperitoneal masses by US does not support screening for
the diseases in healthy subjects. However, if it is done as part of a general
health examination, examiners should attentively observe not only the kidneys but
also the adrenal gland and retroperitoneal space because clinically important
diseases may be detected.
PMID- 9763072
TI - Retroperitoneal and pelvic extraperitoneal laparoscopy: an international
perspective.
AB - OBJECTIVES: To assess technical preferences and current practice trends of
retroperitoneal and pelvic extraperitoneal laparoscopy. METHODS: A questionnaire
survey of 36 selected urologic laparoscopic centers worldwide was performed.
RESULTS: Twenty-four centers (67%) responded. Overall, 3988 laparoscopic
procedures were reported: transperitoneal approach (n = 2945) and
retroperitoneal/extraperitoneal approach (n = 1043).
Retroperitoneoscopic/extraperitoneoscopic procedures included adrenalectomy (n =
74), nephrectomy (n = 299), ureteral procedures (n = 166), pelvic lymph node
dissection (n = 197), bladder neck suspension (n = 210), varix ligation (n = 91),
and lumbar sympathectomy (n = 6). Mean number of total laparoscopic procedures
performed in 1995 per center was 41 (range 5 to 86). Major complications occurred
in 49 (4.7%) patients and included visceral complications in 26 (2.5%) patients
and vascular complications in 23 (2.2%). Open conversion was performed in 69
(6.6%) patients, electively in 41 and emergently in 28 (visceral injuries, n =
16; vascular injuries, n = 1 2). Retroperitoneoscopy/extraperitoneoscopy is
gaining in acceptance worldwide: in 1993, the mean estimated ratio of
transperitoneal laparoscopic cases versus retroperitoneoscopic/
extraperitoneoscopic cases per center was 74:26; however, in 1996 the ratio was
49:51. CONCLUSIONS: Retroperitoneoscopy and pelvic extraperitoneoscopy are
important adjuncts to the laparoscopic armamentarium in urologic surgery. The
overall major complication rate associated with
retroperitoneoscopy/extraperitoneoscopy was 4.7%.
PMID- 9763074
TI - Nephron-sparing surgery for renal angiomyolipoma.
AB - OBJECTIVES: Angiomyolipoma (AML) is a benign renal tumor that may require
treatment because of associated local complications. The present study was
undertaken to evaluate the efficacy of nephron-sparing surgery (NSS) in the
management of renal AML, with respect to the long-term preservation of renal
function and absence of tumor recurrence. METHODS: From 1980 to 1997, 27 patients
underwent NSS for treatment of renal AML. The clinical presentation, surgical
approach, and outcome in these patients were analyzed. Surgical treatment for
renal AML was indicated because of associated symptoms, size of 4.5 cm or
greater, and/or suspicion of renal malignancy. RESULTS: In symptomatic patients
(52%) the most common presenting signs or symptoms were pain (50%),
retroperitoneal hemorrhage or shock (43%), hematuria (36%), hypertension (7%),
palpable mass (7%), and anemia (7%). Two patients had tuberous sclerosis. Fifteen
patients had a solitary functioning kidney (group I), 6 patients had an impaired
contralateral kidney (group II), and 6 patients had a normal contralateral kidney
(group III). All operations were performed in situ. There were no operative
deaths. All operated kidneys functioned postoperatively, and no patient required
dialysis. The mean postoperative serum creatinine level in groups I, II, and III
was 1.81, 0.98, and 0.97 mg/dL, respectively. No patients have developed
recurrent AML, related symptoms, or required dialysis with follow-up to 177
months (median 39). CONCLUSIONS: When surgical treatment for renal AML is
indicated, NSS can be performed with a high success rate even in patients with a
very large tumor involving a solitary kidney.
PMID- 9763075
TI - Partial nephrectomy: alternative treatment for selected patients with renal cell
carcinoma.
AB - OBJECTIVES: To analyze the experience and the results of partial nephrectomy in a
single institution over the last 10 years in order to optimize patient selection
and minimize morbidity. METHODS: This is a retrospective chart review of 64
patients (mean age 56.6 years, range 18 to 88; 43 men, 21 women) who underwent 66
partial nephrectomies at the Brigham and Women's Hospital between 1987 and 1997.
Preoperatively, 62% of the patients had no symptoms, whereas 38% had pain and/or
hematuria. The indications were elective in 23 patients, solitary kidney in 28
(14 with bilateral asynchronous tumor), bilateral synchronous tumor in 7, von
Hippel-Lindau disease with normal contralateral kidney in 3, lymphoma in 3, and
other indications in 2 patients. Surgery was performed for solid or indeterminate
renal mass suspected of being renal cell carcinoma in 58 patients. RESULTS: The
most common final pathologic diagnosis was renal cell carcinoma in 47 procedures.
One or more complications occurred after 18 procedures (15 with solitary kidney
and 3 in patients with normal contralateral kidney) or 27% of the patients. The
most common complication was an increased creatinine level (two times the
baseline), occurring in 10 procedures (15.1%). Transfusion was necessary in 37 of
66 procedures (56%), and the mean blood loss was 836 cc (range 100 to 3200).
Regarding renal function, 85% of the patients had a minimal increase in
creatinine of less than 0.5 mg/dL after surgery (all patients with a normal
contralateral kidney are in this group); 3 patients required either temporary (n
= 1) or permanent (n = 2) dialysis. Other complications are also described. The
mean length of stay among 65 patients was 6.5 days (range 3 to 14). The
differences between length of stay, blood loss, and tumor size were statistically
significant between the solitary kidney group and the elective indications group
(P < 0.001). CONCLUSIONS: Nephron sparing surgery is feasible and relatively safe
in patients with a normal contralateral kidney. Awareness of potential
complications should aid in the selection of appropriate patients for this
procedure.
PMID- 9763076
TI - Pleurotomy, pneumothorax, and surveillance during living donor
nephroureterectomy.
AB - OBJECTIVES: To determine the incidence of and risk factors associated with
pneumothorax after donor nephroureterectomy and to determine the utility of
postoperative chest roentgenography. METHODS: A retrospective review was made of
130 living donor nephroureterectomies performed at one institution (Yale-New
Haven Hospital) using an extraperitoneal flank incision. RESULTS: Incidental
pleurotomy occurred in 11 cases (8.5%). Rib resection was associated with
pleurotomy. Patient age, sex, and side of operation were not associated with
pleurotomy. Ten (91 %) of the 11 cases were identified intraoperatively. One
unrecognized pneumothorax was identified postoperatively with chest
roentgenography; no specific intervention was necessary. CONCLUSIONS: The
extraperitoneal flank incision poses a significant risk for pneumothorax. Most
pneumothoraces will be recognized intraoperatively. No adverse effects were noted
secondary to pneumothorax.
PMID- 9763078
TI - Use of magnetic resonance urography.
AB - OBJECTIVES: Magnetic resonance urography (MRU) is a new technique that uses
heavily weighted T2 coronal images with fat suppression pulse. Urine appears
white on MRU, resembling an intravenous urogram (IVU). Contrast agents are not
necessary. This study describes the use of MRU in the diagnosis and treatment of
patients with hematuria. METHODS: One hundred six patients with microscopic or
gross hematuria and 6 normal volunteers underwent MRU between 1992 and 1995. A
modified, heavily weighted T2 technique with intravenous administration of
furosemide and ureteral compression was used. Thirty-two patients had other
imaging techniques as well for comparison. RESULTS: MRU provided high-resolution
images in almost all cases; 73 (69%) had a normal MRU. Significant findings in
the 33 patients with abnormalities included renal cysts in 17 (51%), renal cell
carcinoma in 6 (18%), transitional cell carcinoma in 5 (15%), ureteropelvic
junction obstruction in 3 (9%), and stones causing obstruction in 6 (18%). Five
patients with renal failure also had good visualization of the entire urinary
tract. MRU was comparable to other imaging modalities except in identifying
nonobstructing calculi. CONCLUSIONS: MRU provides an alternative to conventional
imaging of the urinary tract, especially in those patients who have
contraindications to ionizing radiation and contrast agents. Improvements in
resolution, technique, and cost have to be addressed before it can be used
regularly in urologic practice.
PMID- 9763077
TI - Prognostic factors, recurrence, and survival in transitional cell carcinoma of
the upper urinary tract: a 30-year experience in 252 patients.
AB - OBJECTIVES: To review a large single-center experience of patients treated for
upper tract transitional cell carcinoma (TCC) with extended follow-up in order to
identify patterns of recurrence, assess patient outcomes, and determine the
impact of traditional prognostic factors. METHODS: We reviewed 252 patients
treated surgically for upper tract TCC with a median follow-up of 64 months. Most
patients (77%) underwent nephroureterectomy, whereas 17% were treated with a
parenchymal sparing approach. Traditional prognostic factors including age, sex,
tumor stage, grade, location, and type of surgical treatment were analyzed with
respect to disease recurrence and survival. RESULTS: Disease relapse occurred in
67 patients (27%) at a median time of 12.0 months. Recurrences were local in the
retroperitoneum (9%), the bladder (51%), remaining upper tract (18%), or distant
in the lung, bone, or liver (22%). The 6 patients with local relapse were among
the 73 patients with pT3 or pT4 tumors, and all died of TCC at a median time from
diagnosis of 37 months. Significant prognostic factors for recurrence by
univariate analysis were tumor grade (P = 0.0014) and stage (P = 0.0001). On
multivariate analysis, only tumor stage (P = 0.017) and treatment modality (P =
0.020) were predictors of recurrence. Actuarial 5-year disease-specific survival
rates by primary tumor stage were 100% for Ta/cis, 91.7% for T1, 72.6% for T2,
and 40.5% for T3. Patients with primary Stage T4 tumors had a median survival of
6 months. Although tumor stage and grade correlated with disease-specific
survival on univariate analysis, only patient age (P = 0.042) and stage (P =
0.0001) were significant on multivariate analysis with the type of surgical
procedure performed approaching significance (P = 0.0504). CONCLUSIONS: Primary
tumor stage and surgical procedure performed (radical versus parenchymal sparing)
are important predictors of disease recurrence. Patient age and tumor stage were
the only predictors of disease-specific survival on multivariate analysis with
the type of surgical procedure approaching significance. Radical
nephroureterectomy achieves excellent local control even in the setting of
locally advanced (pT3 or T4) disease. The major clinical feature in this setting
is distant failure, and the development of effective systemic therapy is needed
to improve the outcome in these patients.
PMID- 9763079
TI - Use of ureteroscopy and holmium:YAG laser in patients with bleeding diatheses.
AB - OBJECTIVES: To assess the safety and efficacy of ureteroscopy and holmium laser
in patients with known bleeding diatheses and upper tract calculi or transitional
cell carcinoma (TCC). METHODS: Eight patients with stone disease and 1 patient
with upper tract TCC were treated ureteroscopically with the holmium laser. The
mean age was 58.3 years (range 42 to 74). Six patients were receiving Coumadin,
with a mean international normalized ratio (INR) of 2.1 (normal INR less than
1.1). Two patients were thrombocytopenic, and 1 had von Willebrand's disease.
None of the bleeding diatheses were corrected before surgery. Semirigid or
flexible ureteroscopes were used to access the ureter or intrarenal collecting
system. The holmium laser was used to fragment calculi or ablate tumor. RESULTS:
Only 1 patient had a postoperative bleeding complication related to the
procedure, involving an episode of oliguria secondary to a small ureteral clot.
This cleared without surgical intervention. Another patient developed an episode
of epistaxis after administration of ketorolac for pain. Six of 7 patients who
underwent laser fragmentation for calculi were stone free on follow-up
intravenous urogram at 1 month, and no tumor recurrence was noted in the patient
with TCC (follow-up of 4 months). CONCLUSIONS: Ureteroscopy allowed excellent
access to all regions of the upper tracts, and holmium laser fragmentation of
calculi or ablation of tumor was effective in managing each particular problem.
Use of the holmium laser with ureteroscopic access provides a safe and acceptable
combination for treating upper tract pathology in patients with uncorrected
bleeding diatheses. As a result, these patients can avoid added costs of extended
hospital stay and risks associated with transfusions.
PMID- 9763080
TI - Validation of a harmonized Spanish version of the IPSS: evidence of equivalence
with the original American scale. International Prostate Symptom Score.
AB - OBJECTIVES: To validate the use in Spain of a linguistically harmonized Spanish
version of the International Prostate Symptom Score (IPSS Sp), and to compare it
with the original American scale (IPSS Am). METHODS: Validity and reliability
were studied in 59 patients with benign prostatic hyperplasia (BPH) (age >50
years) and 68 control subjects without BPH (age 18 to 49 years). Construct
validity was assessed by correlating IPSS Sp scores with the EuroQol-5D (EQ-5D),
the Psychological General Well-Being Index (PGWBI), and item 8 (quality of life)
of the IPSS. Discriminatory power was assessed by calculating the area under the
receiver operating characteristic (ROC) curve. Reliability was evaluated using
the test-retest method, and internal consistency was assessed using Cronbach's
alpha. Sensitivity to change was expressed as the effect size in preintervention
versus postintervention scores in 26 additional patients with BPH (age >50 years)
who underwent transurethral resection of the prostate. RESULTS: Correlations of
the IPSS Sp were -0.07 to 0.36 with EQ dimensions; -0.29 with the EQ visual
analogue scale score; 0.14 to 0.41 with PGWBI dimensions; and 0.72 with item 8 of
the IPSS. ROC area was 0.95 +/- 0.02 (standard error). Using a cutoff point of 7,
sensitivity was 83% and specificity was 98%. Test-retest reliability was 0.92 and
Cronbach's alpha was 0.79. Mean preoperative and postoperative IPSS Sp scores
were 25.56 and 8.48, respectively (P < 0.001 ). Overall effect size was 2.52.
These results are similar to those of the original American scale. CONCLUSIONS:
This Spanish translation of the IPSS is valid, reliable, and sensitive to
clinical change and has demonstrated equivalent psychometric properties to the
original American instrument. Scores obtained with the two instruments can
therefore be reliably compared and aggregated when statistically appropriate.
PMID- 9763081
TI - Interstitial cystitis in men.
AB - OBJECTIVES: To determine the personal characteristics, the mode of presentation,
the duration of the delay in diagnosis, the number of misdiagnoses, the means to
achieve diagnosis, and previous treatment provided for a group of men with
interstitial cystitis (IC). METHODS: A chart review of 29 men diagnosed with IC
at our facility from 1988 to 1996 was performed. Basic demographic data,
historical information, laboratory findings, and endoscopic and biopsy results
were tabulated. RESULTS: IC in this series of men was diagnosed at a mean age of
67.3 years. There was approximately a 4-year diagnostic lag between presentation
and diagnosis. The most common prior erroneous diagnoses were prostatitis in 48%
and benign prostatic hypertrophy (BPH) in 38% of the men. Ulcers were encountered
cystoscopically in about 70% and biopsy specimens uniformly showed nonspecific
chronic cystitis at the time of diagnosis. CONCLUSIONS: IC should be considered
in the differential diagnosis of voiding disorders accompanied by irritative
symptoms and pelvic pain in older men. The diagnosis should be especially
considered in men who are refractory to the usual treatments for BPH and
prostatitis. Cystoscopy and bladder distention under anesthesia provided the most
useful objective information in our hands. Biopsy is useful to rule out
inflammatory cancer but adds little to the diagnosis of IC.
PMID- 9763082
TI - Position-related changes in voiding dynamics in men.
AB - OBJECTIVES: To investigate by urodynamic study position-related changes in
uroflowmetry and postvoid residual urine volume (PVR) in men because altered
bladder function in the supine position may be a predisposing factor for urinary
tract infections in the institutionalized elderly. METHODS: Two healthy men, 34
and 59 years of age and living at home, and 53 nursing home residents (mean age
71.8 years, range 46 to 92) were evaluated with uroflowmetry in the standing and
recumbent positions (lying on the left or right side); corresponding PVRs were
measured by transabdominal ultrasonic bladder scanning. The two healthy men were
monitored longitudinally with multiple recordings in both voiding positions, and
the nursing home residents were subjected to two observations: one measurement of
the variable parameters in either position. Differences were considered to be
significant at P < 0.05. RESULTS: The 34-year-old man performed 51 3 flows (368
standing and 145 recumbent). The mean of all the peak flow rates in the upright
(28.2 +/- 4.2 mL/s) versus the recumbent (16.8 +/- 4.1 mL/s) position revealed a
highly significant difference (P = 0.0001). Sixteen urinary flows and
corresponding PVRs were completed by this subject in either voiding position. The
difference between PVRs in the standing (13.1 +/- 14.7 mL) versus recumbent (15.3
+/- 17.5 mL) position was not statistically significant. The 59-year-old man
completed 156 flows (128 standing and 28 recumbent). A highly significant
difference was noted between the mean of all peak flows in the upright (18.9 +/-
4.1 mL/s) versus recumbent (12.6 +/- 2.0 mL/s) position (P = 0.0001). Thirty
seven urinary flows and corresponding PVRs were completed by this individual (10
PVRs were determined after voiding in the standing and 27 after voiding in the
recumbent position). No significant difference was noted between PVRs in the
standing (24.6 +/- 34.4 mL) versus recumbent (16.5 +/- 60.0 mL) position. In the
nursing home residents, the difference between the mean peak flow rates in the
standing (14.5 +/- 8.6 mL/s) versus recumbent (12.4 +/- 6.7 mL/s) position also
reached statistical significance (P = 0.0084). The difference between PVRs in the
standing (60.5 +/- 125.6 mL) versus recumbent (84.8 +/- 186.2 mL) position barely
reached statistical significance (P = 0.0497). CONCLUSIONS: The urinary flow rate
decreases in the recumbent position. Bedridden residents may be predisposed to
urinary tract infections because of alterations in voiding dynamics in the supine
position. This area needs further study.
PMID- 9763083
TI - A prostate gland volume of more than 75 cm3 predicts for a favorable outcome
after radical prostatectomy for localized prostate cancer.
AB - OBJECTIVES: Both the benign and malignant prostatic epithelial components of the
prostate gland contribute to the serum prostate-specific antigen (PSA) level.
Therefore, for a given PSA, the presence of benign hyperplastic prostate tissue
(BHPT) may indicate a lower cancer burden. This study was performed to assess the
impact of varying amounts of BHPT on PSA failure free (bNED) survival after
radical prostatectomy for localized prostate cancer. METHODS: Cox regression
multivariable analyses were performed to assess the ability of the clinical
stage, PSA, biopsy Gleason score, and prostate gland volume to predict time to
postoperative PSA failure in 885 patients. RESULTS: In addition to the PSA (P <
0.0001), biopsy Gleason score of 8 to 10 (P < 0.0001) and of 7 (P = 0.05), and
clinical Stage T2c,3a (P < 0.0001) and T2b (P = 0.0016), the prostatectomy
prostate gland volume (P < 0.0001) was a significant predictor of time to
postoperative PSA failure. Patients with a prostatectomy prostate gland volume
greater than 75 cm3 had a 100% 4-year bNED survival and favorable pathologic
characteristics (pathologic Stage T2, 85%; prostatectomy Gleason score 6 or less,
78% and 7, 22%; and negative margins, 95%) despite a preoperative PSA of 10 to 20
ng/mL and more than 20 ng/mL in 28% and 13% of these men, respectively. In 75% of
these cases, lead time bias because of PSA driven repeat biopsies provided an
explanation. CONCLUSIONS: Lead time bias because of PSA driven repeat biopsy
accounted for the high 4-year bNED survival and favorable pathologic findings for
most patients who had prostate cancer coexisting in a prostate gland comprised of
BHPT and a total gland volume in excess of 75 cm3. An additional explanation is
needed, however, for the remaining patients.
PMID- 9763084
TI - Prostate-specific membrane antigen expression is greatest in prostate
adenocarcinoma and lymph node metastases.
AB - OBJECTIVES: Prostate-specific membrane antigen (PSMA) is an integral membrane
protein highly specific for the prostate. PSMA may be clinically useful for
predicting outcome in patients with prostate cancer. We compared the expression
of PSMA in prostate adenocarcinoma and lymph node metastases in a large series of
patients with node-positive cancer. METHODS: We studied 232 patients with node
positive adenocarcinoma who underwent bilateral pelvic lymphadenectomy and
radical retropubic prostatectomy at the Mayo Clinic between 1987 and 1992.
Immunohistochemistry was performed using monoclonal antibody 7E11-5.3 directed
against PSMA. For each case, the percentage of immunoreactive cells in benign
prostate tissue, adenocarcinoma, and lymph node metastases was estimated in 10%
increments. Intensity was recorded using a scale of 0 to 3 (0 = no staining, 3 =
highest). RESULTS: Cytoplasmic immunoreactivity for PSMA was observed in all
cases in benign epithelium and cancer, and most lymph node metastases. The number
of cells stained was lowest in benign epithelium; cancer and lymph node
metastases were similar (46.2% +/- 27.5% versus 79.3% +/- 18.5% versus 76.4% +/-
26.1%, respectively; all pairs P < 0.05). Intensity of staining was greatest in
primary cancer and lowest in lymph node metastases. CONCLUSIONS: PSMA is
expressed in benign prostatic epithelium and primary cancer in all cases and in
98% of cases with lymph node metastases. Expression of PSMA was greatest in
primary cancer for both percentage and intensity of immunoreactive cells. PSMA
expression allows the identification of benign and malignant prostatic epithelium
and may be a potentially valuable marker in the treatment of patients with
prostate cancer.
PMID- 9763085
TI - Efficacy of one dose fluoroquinolone before prostate biopsy.
AB - OBJECTIVES: To demonstrate the efficacy of a simple preparation for prostate
biopsy (PBX) and to determine its potential cost savings. METHODS: One hundred
fifty consecutive PBXs were performed using a Fleet enema and a single oral dose
(300 mg) of ofloxacin as the pre-PBX preparation. RESULTS: Of the 150 PBXs we
performed, only 1 (0.67%) patient developed a urinary tract infection.
CONCLUSIONS: A simple and inexpensive pre-PBX preparation proved to be successful
in preventing infectious complications and is presented as a potential model for
inclusion in clinical pathways for diagnosing adenocarcinoma of the prostate.
PMID- 9763086
TI - Variability in patient preparation for prostate biopsy among American urologists.
AB - OBJECTIVES: To assess the variability in patient preparation for prostate biopsy
(PBX) among practicing American urologists. METHODS: A survey was sent to 900
practicing American urologists randomly selected by the American Urological
Association computer files. The survey asked about their pre-PBX protocol.
RESULTS: Approximately 63% (568 of 900) of the surveys were returned and showed
considerable differences in pre-PBX protocol among those urologists. The pre-PBX
regimen included prophylactic antibiotics in 98.6% and a cleansing rectal enema
in 81%. Eleven different antibiotics were used, with 20 different doses and 23
different timing-duration regimens. CONCLUSIONS: The pre-PBX preparation is not
standardized among American urologists.
PMID- 9763087
TI - Relationship of ultrasound staging and bilateral biopsy positivity to outcome in
stage T1c prostate cancer treated with radiotherapy.
AB - OBJECTIVES: The strict definition of Stage T1c prostate cancer is that the tumor
is not palpable on digital rectal examination (DRE) or seen on imaging studies
such as ultrasound. The inclusion of ultrasound imaging was brought about without
an understanding of the relationship between ultrasound upstaging and prognosis.
We have also noticed that in clinical practice, treatment decisions are made on
the basis of the finding of bilateral versus unilateral biopsy positivity. The
objectives in this study were to determine the prognostic significance of
upstaging by transrectal ultrasound (TRUS) to uT2 or uT3, and unilateral versus
bilateral biopsy positivity in patients with Stage T1c cancer as determined by
DRE (DRE-Stage T1c patients). METHODS: Between 1987 and 1995 there were 643
patients with DRE-Stage T1-T2 prostate cancer treated with external beam
radiotherapy; 24 had T1a, 76 had T1b, 183 had T1c, 133 had T2a, 168 had T2b, and
59 had T2c. Of these, 135 DRE-Stage T1c patients underwent ultrasound staging and
122 underwent bilateral prostate biopsies. All had pretreatment prostate-specific
antigen values (PSAs) available and no patient received adjuvant androgen
ablation. The median pretreatment PSA was 9.1 ng/mL, median radiotherapy dose was
66.0 Gy, and median follow-up was 41 months. Post-treatment failure was defined
as disease recurrence and/or two elevations in PSA on consecutive follow-up
visits. RESULTS: The 5-year freedom from failure rate for DRE-Stage T1c patients
(71%) was not significantly different from that of DRE-Stage T1b (65%) or DRE
Stage T2a (71%) patients. There was a trend (P = 0.1) toward a worse outcome for
DRE-Stage T2b/T2c patients compared with DRE-Stage T1b/T1c/T2a patients. The
distribution of DRE-Stage T1c patients by ultrasound staging was 29 with uT1c, 88
with uT2, and 18 with uT3 findings. Twenty percent of patients had bilateral
positive biopsy specimens. In univariate and multivariate analyses, the only
correlates of patient outcome were pretreatment PSA (P < or = 0.002) and
isocenter dose (P = 0.03). TRUS upstaging had no effect on freedom from failure;
uT1c patients had about the same risk of relapse or a rising PSA as uT2 or uT3
patients. Patients with bilateral positive prostate biopsy specimens had about
the same prognosis as those with unilateral positive biopsy specimens.
CONCLUSIONS: For patients with DRE-Stage T1c prostate cancer, the data indicate
that ultrasound staging and bilateral biopsy positivity are not predictive of
outcome for patients treated with external beam radiotherapy and treatment
decisions should not be based on these parameters.
PMID- 9763088
TI - Estimation of prostate cancer volume by multiple core biopsies before radical
prostatectomy.
AB - OBJECTIVES: To investigate whether tumor volume, an important prognostic factor
in prostate cancer, could be estimated from the amount of cancer in multiple core
biopsies. METHODS: In 80 men, transrectal ultrasound-guided biopsies were taken
from focal lesions detected by ultrasound and 8 to 10 standardized positions,
including sextant biopsies (apex, midmedial, base) and midlateral and transition
zone biopsies. The cancer length in the biopsies was measured. After radical
prostatectomy, the prostates were totally embedded, whole-mounted, and tumor
volume was measured planimetrically. RESULTS: The tumor volume correlated
significantly with the total cancer length of all biopsies (r = 0.56) and of the
sextant biopsies (r = 0.39). It was found that midlateral and transition zone
biopsies provided independent information when included in a multiple regression
model with tumor volume as the dependent variable and the sextant biopsies as
explanatory variables. All men (n = 6) with less than 3 mm cancer length in only
one positive biopsy and a Gleason score less than 7 had a tumor volume less than
1 mL. Nine of 10 men with less than 7 mm of cancer in one positive biopsy and
Gleason score less than 7 had tumors smaller than 1 mL. Sextant biopsies did not
reliably predict cancer volumes less than 1 mL. CONCLUSIONS: The cancer yield of
8 to 10 biopsies correlated better with the volume of prostate cancer than
sextant biopsies. This extended biopsy protocol could be used to predict cancers
of less than 1 mL in volume.
PMID- 9763089
TI - Repeat transrectal ultrasound-guided prostate biopsy: a strategy to improve the
reliability of needle biopsy grading in patients with well-differentiated
prostate cancer.
AB - OBJECTIVES: Gleason grade from prostate needle biopsy (PNB) specimens is
important in guiding therapeutic decision making in patients with localized
prostate cancer. Recent data from our institution suggest a significant
discordance between Gleason grading from PNB versus the actual pathologic grade
at radical prostatectomy (RRP). Of most concern is that a substantial proportion
of patients with Gleason score of 6 or less from PNB actually have Gleason score
of 7 or more at RRP. Under classic measurement theory, one useful way to improve
the reliability of an inherently unreliable test is to repeat it. We investigated
this strategy in an effort to reduce undergrading errors. METHODS: The control
group of patients (n = 51) from our neoadjuvant androgen deprivation protocol was
used as the test (two-biopsy) group in this study. These patients underwent two
separate PNBs before RRP. We used the highest Gleason score from the two biopsies
in these patients and compared the error rates with a concurrent group of
patients treated at our institution (n = 226) who had only one set (single-biopsy
group) of prostate biopsies. All pathologic slides were reviewed at our
institution. Any PNB grade of 6 or less that was scored as 7 or more on final
pathology was considered significant. RESULTS: Mean age, prostate-specific
antigen levels, and stage distribution were not significantly different between
these two groups. In the single-biopsy group, 165 patients had PNB Gleason score
of 6 or less. Of these patients, 63 (38%) had final pathologic grade of 7 or
more. In the two-biopsy group, 37 patients had PNB Gleason score of 6 or less. Of
these patients, only 7 (19%) had final pathologic grade of 7 or more (P = 0.04).
CONCLUSIONS: Prostate rebiopsy minimizes the inherent unreliability of PNB
derived grade and should be considered for patients in whom watchful waiting or
nomogram-based therapy has been selected.
PMID- 9763090
TI - Evaluation of staging lymphadenectomy in prostate cancer.
AB - OBJECTIVES: To prospectively evaluate a clinical algorithm that predicts nodal
status in patients with prostate cancer and to assess the impact on the outcome.
METHODS: Between September 1988 and December 1994, 192 patients with organ
confined prostate cancer and considered surgical candidates for radical perineal
prostatectomy (RPP) were stratified using the algorithm: prostate-specific
antigen (PSA) 20 ng/mL or less, Gleason score 7 or lower, and clinical Stage T2a
or lower. Patients failing any of these criteria were placed in the high-risk
group and underwent a pelvic lymphadenectomy. Patients who satisfied all the
criteria were placed in the low-risk group and underwent RPP without evaluation
of the pelvic lymph nodes. Another contemporaneous cohort of patients (n = 65)
underwent pelvic lymphadenectomy and radical retropubic prostatectomy (RRP)
without use of the algorithm and were used as a control group. Patients were
monitored for at least 24 months. RESULTS: In the RPP group, 177 patients were
considered low risk according to the algorithm and were not offered staging
lymphadenectomy before surgery, whereas 15 patients were categorized as high risk
for metastasis and underwent staging lymphadenectomy. In the RRP and
lymphadenectomy group, 41 patients were considered at low risk and 24 at high
risk of disease spread according to the algorithm. In the RPP group, low-risk
patients (no lymphadenectomy) had a PSA recurrence rate (27%) similar to that of
low-risk patients in the RRP group with negative lymph nodes (29%), P = 0.8.
Similarly, high-risk patients with negative lymph nodes in both groups had a
similar recurrence rate (53% for RPP and 50% for RRP). Univariate logistic
regression analysis showed that PSA was the most significant predictor for
disease recurrence (P = 0.0004) followed by preoperative Gleason scores (P =
0.02) and clinical stages (P = 0.03). Multivariate stepwise analysis demonstrated
that Gleason score and clinical stage did not add to the prediction of recurrence
over PSA alone. CONCLUSIONS: Staging lymphadenectomy can be omitted in low-risk
patients without deleterious effects on the outcome as measured by PSA
recurrence.
PMID- 9763091
TI - Bladder neck prop using vaginal wall island for intrinsic sphincteric deficiency
in elderly patients: a new technique.
AB - OBJECTIVES: A simple new technique, using a trapezoid island of vaginal wall, is
described for elderly female patients undergoing transvaginal pelvic prolapse
repair and suffering from stress urinary incontinence secondary to intrinsic
sphincteric deficiency. METHODS: Fifteen elderly women underwent bladder neck
prop in association with other pelvic prolapse surgery. The mean follow-up period
was 20 months. RESULTS: Twelve of 14 patients (85.7%) were dry. One patient was
lost to follow-up. CONCLUSIONS: Bladder neck prop provided urethral and bladder
neck compression and support. The major advantage of this approach is avoiding
extensive dissection and/or abdominal incision in elderly female patients.
PMID- 9763092
TI - Patient perspective of long-term outcome of augmentation cystoplasty for
neurogenic bladder.
AB - OBJECTIVES: Although the urologic outcomes of augmentation cystoplasty for
neurogenic bladder dysfunction are well known, additional information about the
patient perspective is needed. The aim of this study was to assess patient
perspective using a standardized questionnaire. METHODS: Fifty-nine patients, who
had undergone augmentation enterocystoplasty as part of reconstruction mainly to
correct hyperactive bladders and incontinence, were subjected to a questionnaire
after a median of 76.1 postoperative months. The questionnaire addressed
medications, catheterization, incontinence, bowel dysfunction, and satisfaction
with urinary tract management. The urologic outcomes regarding upper and lower
tract changes, complications, and reinterventions were documented as well.
RESULTS: The patients experienced a significant increase in bladder capacity and
decrease in pressure at capacity (P < 0.0001). Normal upper tracts remained
normal and there was either improvement or stabilization of hydronephrosis.
Twenty-four patients (40.6%) had one or more complications, with 21 requiring
reinterventions. Twenty-five percent of patients required the reintervention
within the first 25 months, and the median time to reintervention was almost 10
years. Thirty-five patients took medications such as anticholinergics,
antidiarrheals, or antibiotics. Fifty-six patients were treated with clean
intermittent catheterization (CIC) at a mean interval of 4.6 hours. Seven
patients had some difficulty with CIC. Thirty-nine patients (67%) were dry, and
17 had mild and 3 severe incontinence. Eleven patients (18.6%) reported bowel
dysfunction, although 7 had it preoperatively. Almost all patients were very
satisfied with their urologic management. CONCLUSIONS: The high degree of patient
satisfaction attests to the value of the procedure. The complication and
reintervention rates underscore the importance of long-term follow-up.
PMID- 9763093
TI - Stimulated pressure profile at rest: a noninvasive method for assessing urethral
sphincter function.
AB - OBJECTIVES: To validate a method for assessing urethral sphincter muscle function
by recording rises in intraurethral pressure during repetitive pudendal nerve
stimulations. METHODS: A supine urethral pressure profile at rest was performed
on 12 stress-continent and 28 stress-incontinent patients during repetitive
pudendal nerve stimulations applied near the ischial spine, and the intraurethral
pressure increases were calculated for each third of the urethral functional
length. RESULTS: No significant difference in intraurethral pressure increases
was seen between continent and stress-incontinent women. On the various
regression curves, the intraurethral pressure increases showed a significant
correlation with maximal urethral closure pressure values at rest and at stress
(r = 0.36 to 0.54) and with the patient's age (r = 0.46), but not with pudendal
nerve conduction times to the urethral sphincter on either side (r = 0.14 and
0.19). CONCLUSIONS: This method (1) measures intraurethral pressure increases
that correlate well with the anatomic location of the urethral sphincter muscle,
(2) shows there is no significant difference between them in continent and stress
incontinent patients, except in patients with a low-pressure urethra, and (3)
demonstrates that they correlate well with the maximal urethral closure pressure
and the patient's age, but not with pudendal motor latencies to the urethral
sphincter. This method gives us a mapping of the urethral sphincter activity,
explaining why some patients with a low-pressure urethra have less urinary loss
than others with the same urethral closure pressure.
PMID- 9763094
TI - Clinical aspects of vasectomies performed in the United States in 1995.
AB - OBJECTIVES: Currently, no surveillance system collects data on the numbers and
characteristics of vasectomies performed annually in the United States. This
study provides nationwide data on the numbers of vasectomies and the use of no
scalpel vasectomy, various occlusion methods, fascial interposition, and
protocols for analyzing semen after vasectomy. METHODS: A retrospective mail
survey (with telephone follow-up) was conducted of 1800 urology, family practice,
and general surgery practices drawn from the American Medical Association's
Physician Master File and stratified by specialty and census region. Mail survey
and telephone follow-up yielded an 88% response rate. RESULTS: In 1995,
approximately 494,000 vasectomies are estimated to have been performed by 15,800
physicians in the United States. Urologists performed 76% of all vasectomies, and
nearly all (93%) urology practices performed vasectomies in 1995. Nearly one
third (29%) of vasectomies in 1995 were no-scalpel vasectomies, and 37% of
physicians performing no-scalpel vasectomies taught themselves the procedure. The
most common occlusion method in 1995 (used for 38% of all vasectomies) was
concurrent use of ligation and cautery. In 1995, slightly less than half (48%) of
all physicians surveyed interposed the fascial sheath over one end of the vas
when performing a vasectomy. Protocols for ensuring azoospermia varied: 56% of
physicians required one postvasectomy semen specimen; 39% required two, and 5%,
three or more. CONCLUSIONS: No-scalpel vasectomy, used by nearly one third of
U.S. physicians, has become an accepted part of urologic care. Physicians'
variations in occlusion methods, use of fascial interposition, and postvasectomy
protocols underscore the need for large scale, controlled, and statistically
valid studies to determine the efficacy of occlusion methods and fascial
interposition, as well as whether azoospermia is the only determination of a
successful vasectomy.
PMID- 9763095
TI - Testicular sperm extraction for nonobstructive azoospermia: results of a
multibiopsy approach with optimized tissue dispersion.
AB - OBJECTIVES: Testicular sperm extraction (TESE) is an effective procedure to
retrieve sperm from some men with nonobstructive azoospermia (NOA). To optimize
treatment effectiveness, we have reviewed our experience with TESE for NOA to
better understand technical factors needed for sperm retrieval and lead to an
optimized approach to TESE. METHODS: Eighty-one men with confirmed NOA underwent
attempted TESE using an open technique under optical magnification. Each testis
sample was dispersed and examined in the operating room. Sequential biopsy
attempts were made until sperm were visualized or until further biopsies were
thought to jeopardize testicular blood flow. In 20 patients, standard biopsy and
initial mechanical dispersion of the seminiferous tubules were compared with the
passage of tissue through a 24-gauge angiocatheter after initial dispersion to
quantitate spermatozoal yield. RESULTS: Overall, 47 (58%) of 81 patients who
underwent TESE had direct intraoperative visualization of spermatozoa. The
average number of biopsy attempts for all patients was 8.9 and for patients with
sperm isolated 6.4 (P = 0.002). Passage of the testicular tissue suspension
through a 24-gauge angiocatheter increased sperm retrieval in matched tissue
specimens from 83,000 to 390,000 or 470% over that achieved with standard
dispersion alone (P = 0.005). An initial, substantive tissue biopsy revealed
sperm in only 23 (28%) of 81 patients. Using this approach with sequential
biopsies under optical magnification, no patient had evidence of testis injury or
devascularization. CONCLUSIONS: Because multiple TESE procedures can cause
transient and permanent alterations in testicular function, it is imperative to
perform TESE as safely and as efficiently as possible. We suggest that open TESE
with optical magnification provides a safe method of retrieving sperm. A single
biopsy for extraction is inadequate to detect spermatozoa for men with NOA. Use
of the needle dispersion technique with passage of testicular tissue through an
angiocatheter enhances detection of sperm and could potentially reduce the need
for subsequent biopsies. An algorithm to minimize biopsies and allow sperm
retrieval is presented.
PMID- 9763096
TI - Percutaneous nephrolithotomy in infants and preschool age children: experience
with a new technique.
AB - OBJECTIVES: To develop a less invasive method for performing percutaneous
nephrolithotomy (PCNL) with the intent of decreasing the morbidity of the
procedure in young children. METHODS: A novel percutaneous renal access technique
("mini-perc") was developed using an 11F peel-away vascular access sheath. Tract
dilation and insertion of the sheath into the collecting system was performed
with a single pass over an access wire. PCNL was performed using pediatric
instruments and electrohydraulic lithotripsy. Sheath design improvements were
implemented that make it specific for pediatric PCNL. RESULTS: Eleven procedures
have been performed with the 11F sheath. Patient age ranged from 2 to 6 years
(mean 3.4) and weight from 5 to 24 kg (mean 12.5). The average stone burden was
1.2 cm2. Mean procedure time, estimated blood loss, and length of hospitalization
were 203 minutes, 25 mL, and 6 days, respectively. Six (85%) of 7 patients are
currently stone free with an average follow-up of 12 weeks. No patient required
transfusion, developed urosepsis, or had a procedure-related complication. One
procedure was performed in an outpatient setting with no postoperative
nephrostomy tube. CONCLUSIONS: The 11F "mini-perc" technique was successful in
rendering 85% of patients stone free with minimal morbidity. Its advantages over
obtaining access with standard 24 to 34F access sheaths include a smaller skin
incision, single-step dilation and sheath placement, good working access for
pediatric instruments, variable length, and lower cost. In addition, the
hypothesized decrease in renal and body wall trauma may result in less pain,
reduced severity or risk of complications, and shorter hospital stays including
the possibility of performing "tubeless" outpatient PCNLs. Further study is
needed to confirm these possibilities.
PMID- 9763098
TI - 20th biannual meeting of the Society for Fetal Urology.
PMID- 9763097
TI - Cecoappendicovesicostomy: conduit-lengthening technique for use in continent
urinary reconstruction.
AB - OBJECTIVES: To describe a conduit-lengthening technique for use in continent
cutaneous appendicovesicostomy (Mitrofanoff procedure). METHODS: Fifteen
consecutive patients (4 male, 11 female) with a mean age of 14.2 years underwent
tubularized cecal augmentation as a means to lengthen the catheterizable conduit
while performing continent cutaneous appendicovesicostomy. RESULTS: All patients
successfully underwent appendiceal lengthening by tubularizing the cecum, thus
creating a continent cutaneous cecoappendicovesicostomy. With a mean follow-up of
18.7 months, all patients have a working catheterizable conduit. One case of
stomal stenosis occurred, producing a 6.7% conduit-related complication rate.
CONCLUSIONS: Cecoappendicovesicostomy is a safe and useful means of conduit
lengthening for patients undergoing continent cutaneous appendicovesicostomy
(Mitrofanoff procedure).
PMID- 9763099
TI - Images in clinical urology. Suture nidus as a cause for renal nephrolithiasis.
PMID- 9763100
TI - Images in clinical urology. Venous cavernous hemangioma of the testis.
PMID- 9763102
TI - Radical prostatectomy in patients with indwelling inflatable penile prosthesis.
AB - Patients with impotence who have undergone placement of an inflatable penile
prosthesis (IPP) and then subsequently are diagnosed with carcinoma of the
prostate (CaP) present a surgical dilemma. We performed radical retropubic
prostatectomy on 3 patients with clinically localized CaP and an indwelling IPP.
At laparotomy all 3 patients had the IPP reservoir relocated to facilitate
dissection. In each case the reservoir was relocated to the left hypogastrium
within the extraperitoneal space without disrupting the vacuum tubing system.
There were no complications related to IPP, no IPP was injured, and each IPP was
reactivated successfully 6 weeks after surgery.
PMID- 9763101
TI - Bilateral adrenal cortical adenomas in primary hyperaldosteronism.
AB - Bilateral adrenal cortical adenomas in the presence of primary hyperaldosteronism
is an extremely rare condition. We present a case of primary hyperaldosteronism
in which a unilateral hypersecreting aldosterone-producing adenoma coexisted with
a large, contralateral adrenal mass ultimately found to be consistent with
cortical adenoma. Management consisted of total adrenalectomy and enucleation of
adenoma from the opposite adrenal. The patient is normotensive 3 years after
surgery. Enucleation as a successful approach to hyperfunctioning cortical
adenomas is proposed.
PMID- 9763103
TI - Repair of penile rupture through a high-scrotal midline raphe incision.
AB - We report a case of penile rupture after a self-inflicted injury, which was
repaired through a 4-cm midline raphe incision in the high-scrotal position. A
single injury to the right lateral corpora cavernosum was identified and
repaired. This incision allows for exposure of all three corporal bodies and
results in excellent cosmesis. Creating artificial tumescence with intracorporal
saline injection can be useful in identifying small or multiple sites of corporal
injury. This may obviate the need for performing a routine degloving procedure,
which results in unnecessary dissection, increased edema, and potential visible
scarring of the penile skin.
PMID- 9763105
TI - Androgen induction of DNA synthesis in the rat penis.
AB - OBJECTIVES: The androgen sensitivity of the mammalian penis has long been
appreciated. However, the precise biochemical and structural sequelae of
alterations in testosterone, and the mechanisms thereof, remain to be elucidated.
Recently, the androgen dependence of rat penile erectile tissue was further
clarified at our institution, where the induction of apoptosis was demonstrated
in response to castration. In continuity, we report the results of a follow-up
study of the regenerative capacity of the regressed, castrated rat penile
erectile tissue when testosterone is replenished. METHODS: Three groups of rats
were used: normal control rats, castrated without testosterone replenishment, and
castrated with subsequent testosterone replenishment. In the third group,
castrated rats were given testosterone and killed at 24-hour intervals over 4
days. Specimens of the penis, small bowel, and prostate were obtained from all
animal groups. Immunohistochemical identification of intraperitoneally
administered 5-bromo-2'-deoxyuridine, a thymidine analogue, was performed to
detect new DNA synthesis. The incorporation of this molecule into high molecular
weight nuclear DNA served as a measure of DNA synthesis and, hence, cellular
proliferation. RESULTS: Testosterone-replenished castrated rat penile stromal
cells, both cavernosal and spongiosal, showed more enhanced proliferative
activity than those of both castrated unreplenished and uncastrated control rats.
Trichrome staining permitted the differentiation of responsive cell subsets.
Various cell types were found to respond to replenished testosterone, including
myocytes, fibrocytes, endothelial cells, and Schwann cells. Pronounced DNA
synthesis occurred as early as 48 hours after the replenishment of testosterone.
For purposes of technique validation, sections of small bowel were examined, in
which glandular crypt cells would be expected to show rapid turnover. The nuclei
of these bowel sections stained in all animal groups throughout the experiment,
thus validating the staining technique. The technique of castration and
testosterone replenishment was validated by confirming the known response of rat
ventral prostate to androgen withdrawal and replenishment. CONCLUSIONS: Our
findings provide evidence that testosterone induces cellular proliferation and
new DNA synthesis in the penile erectile tissue of castrated rats. This response
to testosterone is not limited to one cell type, but rather is multicellular.
PMID- 9763106
TI - History of direct vision internal urethrotomy.
AB - Throughout medical history, the treatment of urethral strictures ranged from
catheterization, the insertion of bougies, and the application of caustics to
different methods of dilation, blind internal urethrotomy, and open surgery. The
rise of endoscopy in the 19th century added the possibility of direct vision
internal urethrotomy to this therapeutic spectrum. The development of this
endourologic method is recapitulated from the first report in 1865 to the gold
standard of cold knife urethrotomy in 1971 and later modifications (eg, advanced
laser techniques).
PMID- 9763104
TI - Hematuria and death secondary to aortoureteric fistula.
AB - Ureteroarterial fistulae are extremely rare after previous vascular surgery.
Eight cases have been described in the English literature. This is the first
example of a vascular communication between the aorta and the ureter. All
previous cases were ureteroiliac fistulae. Known hydronephrosis in the presence
of prior vascular grafting and heavy hematuria should alert the clinician to the
possibility of a ureteroarterial fistula.
PMID- 9763107
TI - Management of possible sexual, injecting-drug-use, or other nonoccupational
exposure to HIV, including considerations related to antiretroviral therapy.
Public Health Service statement. Centers for Disease Control and Prevention.
AB - The most effective methods for preventing human immunodeficiency virus (HIV)
infection are those that protect against exposure to HIV. Preventive behaviors
include sexual abstinence, sex only with an uninfected partner, consistent and
correct condom use, abstinence from injecting-drug use, and consistent use of
sterile equipment by those unable to cease injecting-drug use. Some healthcare
providers have proposed offering antiretroviral drugs to persons with
unanticipated sexual or injecting-drug-use HIV exposure to prevent transmission.
However, because no data exist regarding the efficacy of this therapy for persons
with nonoccupational HIV exposure, it should be considered an unproven clinical
intervention. Health-care providers and their patients may opt to consider using
antiretroviral drugs after nonoccupational HIV exposures that carry a high risk
for infection, but only after careful consideration of the potential risks and
benefits and with a full awareness of the gaps in current knowledge. To address
concerns related to providing antiretroviral agents to persons after
nonoccupational HIV exposure, CDC convened a meeting in July 1997 of scientists,
public health experts, clinicians, members of professional associations,
representatives from industry, ethicists, and members of affected communities.
This report reviews the topics raised at the meeting, provides background
information on patient management options, and presents considerations for
antiretroviral therapy.
PMID- 9763108
TI - Ex vivo expansion of immature 4-hydroperoxycyclophosphamide-resistant progenitor
cells from G-CSF-mobilized peripheral blood.
AB - The application of ex vivo expansion to cell products pharmacologically purged in
vitro may provide sufficient numbers of cells for rapid engraftment in a product
with reduced tumor burden. To pursue this possibility we evaluated the effect of
4-hydroperoxycyclophosphamide (4-HC) treatment on granulocyte colony-stimulating
factor-mobilized peripheral blood stem cells (G-PBSC) and their subsequent
expansion potential. A small number of G-PBSC CD34+ cells are resistant to 4-HC
and are phenotypically and functionally immature. 4-HC-resistant G-PBSC cells are
CD34+ bright, CD38+/-, DR(lo), CD13(lo), CD33-, CD71-, and rhodamine dull. In six
experiments, treating G-PBSC with 60 microg/mL of 4-HC at 37 degrees C for 30
minutes reduced the number of colony-forming units (CFUs) per 5000 CD34+ cells by
96.3% (from 1333 +/- 137 to 46.5 +/- 11). This purging also reduced the frequency
of 5-week long-term culture initiating cells (LTC-ICs) from 1/39 (range 1/27 to
1/62) to <1/1680 (range 1/1180 to 1/2420). Ex vivo expansion cultures were used
to compare the proliferative potential of treated and untreated CD34+ cells.
These cells were cultured with either the HS-5 stromal cell line serum-deprived
conditioned media supplemented with 10 ng/mL kit ligand (HS-5CM/KL) or a
recombinant growth factor mix (GFmix) containing 10 ng/mL each of interleukin
(IL)-1, IL-3, IL-6, KL, granulocyte colony-stimulating factor, granulocyte
macrophage colony-stimulating factor, and 3 U/mL of erythropoietin. Culturing
untreated CD34+ G-PBSC with 10% HS-5CM/KL increased total nucleated cells by 460
fold after 15 days. Progenitors, which were measured as CFUs, also increased by
47-fold over the same period. More significantly, culturing the 4-HC-treated
CD34+ cells with HS-5/KL increased CFUs 98-fold and the nucleated cells increased
4573-fold. The absolute number of CFUs present after expansion of the 4-HC
resistant cells with HS-5CM/KL was threefold higher than that detected before
purging and significantly higher than that obtained with GFmix. These data
indicate that G-PBSC contain a very immature pool of cells not detectable using
the 5-week LTC-IC assay, but have extremely high proliferative potential.
Additionally, pharmacological purging of G-PBSC greatly reduces mature cells
while retaining an immature population. Also significant is the finding that
supernatant from the HS-5 bone marrow stromal cell line plus KL can fully
regenerate progenitors from the 4-HC-resistant CD34+ G-PBSC.
PMID- 9763110
TI - CD20 is a molecular target for scFvFc:zeta receptor redirected T cells:
implications for cellular immunotherapy of CD20+ malignancy.
AB - The CD20 molecule was evaluated as a B-cell lymphoma target epitope for T cells
expressing a CD20-specific single-chain FvFc-zeta (scFvFc:zeta) chimeric
receptor. A cDNA construct consisting of a murine kappa leader sequence, CD20
specific scFv, human immunoglobulin (Ig) G1 hinge-C(H)2-C(H)3, the human CD4
transmembrane, and the intracellular signaling domain of the human CD3 complex's
zeta chain was synthesized by polymerase chain reaction splice-overlap extension.
The human CD4+ Jurkat cell line was electroporated with the CD20-specific
scFvFc:zeta construct cloned into the mammalian expression vector pcDNAneo.
Western blot analysis of transfectant whole cell lysate with an anti-zeta
antibody demonstrated the expression of both endogenous zeta and the chimeric
receptor protein, with a mobility consistent with the expected molecular weight
of 66 kD under reducing conditions; nonreduced lysate revealed a chimeric
receptor complex of approximately 132 kD. The scFvFc:zeta receptor was present on
the cell surface as detected by flow cytometry of T-cell transfectants stained
with an anti-mouse Fab-specific antibody and anti-human Fc gamma-specific
monoclonal antibody. Coculture of Jurkat transfectants with CD20+ lymphoma cells
resulted in the accumulation of interleukin (IL)-2 in culture supernatants as
detected by ELISA. IL-2 production was triggered by the specific interaction
between the CD20 molecule and the scFvFc:zeta as IL-2 was not detected in
cultures with mock transfected Jurkat cells or CD20- stimulator cells.
Furthermore, IL-2 production was inhibited by the addition of a soluble anti-CD20
monoclonal antibody to cocultured Jurkat transfectants and CD20+ stimulator
cells. The capacity of CD20 to trigger the lytic machinery of scFvFc:zeta
expressing cytotoxic T lymphocytes (CTLs) was assessed using the murine allo
specific CD8+ CTL clone 2c. CD20-specific redirected cytolytic activity against
human lymphoma targets was observed with 2c transfectants in a 4-hour chromium
release assay. These results demonstrate that CD20 can serve as a target epitope
for scFvFc:zeta receptor-expressing T cells.
PMID- 9763109
TI - c-Kit and CD38 are expressed by long-term reconstituting hematopoietic cells
present in the murine yolk sac.
AB - Murine fetal liver (FL) and adult bone marrow (BM) hematopoietic stem cells
(HSCs) are characterized by cell surface expression of CD38 and c-kit. Because
murine yolk sac (YS) HSC activity precedes the initiation of FL hematopoiesis, we
investigated whether YS-derived HSCs also expressed c-kit and CD38. c-Kit+ CD38+
lineage- cells derived from day 9 YS as well as adult BM were found to be
enriched in high proliferative potential colony-forming cells. c-Kit+ CD38+
lineage- YS or adult BM cells were capable of long-term reconstitution (>6
months) of busulfan-conditioned newborn or lethally irradiated adult mice,
respectively. In contrast, c-kit+ CD38- lineage- populations from both tissues
were enriched in lineage-committed progenitors and had no long-term HSC activity.
We concluded that c-kit and CD38 are cell surface markers of HSCs expressed
throughout murine ontogeny.
PMID- 9763111
TI - Effect of CD34+ peripheral blood progenitor cell dose on hematopoietic recovery.
AB - The CD34+ cell surface antigen is expressed on progenitor cells required for
blood stem cell transplantation. The number of cells expressing CD34+ can be used
to assess the peripheral blood progenitor cell (PBPC) graft quality and predict
hematopoietic recovery after engraftment. Because there is considerable
variability among centers in the determination of CD34+ cell counts,
standardizing flow cytometry methodology is essential. It is necessary to define
a minimum safety threshold CD34+ cell dose for hematopoietic cell
transplantation. This minimum dose would define a cell number in the graft, below
which a proportion of patients would be expected to have delayed hematopoietic
recovery or failure to engraft. We reviewed data from numerous studies. Although
1-2 x 10(6) CD34+ cells/kg can be considered an adequate graft, available data
suggested that doses >5 x 10(6) CD34+ cells/kg were associated with more rapid
engraftment and a lower probability of graft failure. The risk of delayed
recovery was inversely related to CD34+ cell dose. Delayed recovery may result in
greater transfusion requirements, longer hospitalization, increased antibiotic
use and growth factor support, and higher health care costs. The extent of prior
chemotherapy and radiation treatment are major risk factors for poor PBPC
collection. To achieve an optimal CD34+ cell yield, PBPC collection should be
initiated early during therapy. PBPC collection should be coordinated with the
anticipated number of chemotherapy cycles, duration of chemotherapy, interval
between chemotherapy and apheresis, need for radiotherapy, and exposure to the
more progenitor cell-toxic drugs such as carmustine or busulfan.
PMID- 9763112
TI - Understanding molecular biology.
AB - Vascular disease is more commonly being studied at a molecular level. The
knowledge derived is being applied to our understanding of clinical vascular
disease processes and reconstruction outcome. Furthermore, applications are
increasingly found for diagnosis and even intervention. The fundamental concepts
and techniques involved in molecular biology are presented.
PMID- 9763113
TI - The pathophysiology of atherosclerosis.
AB - Complications resulting from advanced atherosclerosis are the most common
indication for vascular reconstructive surgery. Atherosclerosis is a systemic
disease affecting the entire arterial tree, but lesions involving the coronary,
extracranial cerebral, and lower extremity circulations have the most clinical
significance for surgeons. The pathogenesis of atherosclerosis involves a complex
series of events, similar to a chronic inflammatory process, with the formation
of atherosclerotic plaque as the end result. Injury to the endothelial cell of
the artery, resulting in endothelial cell dysfunction, is the first step in the
process. Activated endothelial cells attract leukocytes and vascular smooth
muscle cells (VSMC), which accumulate and proliferate in the arterial wall. These
cellular components produce an excessive amount of connective tissue matrix. The
ultimate end point is the formation of a mature fibrous plaque. Symptoms occur
when advanced lesions are complicated by plaque rupture, hemorrhage into the
plaque, emboli, or thrombosis. A thorough understanding of the pathogenesis of
atherosclerosis is essential for the development of strategies for the prevention
of the disease, and for the development of new and effective treatments.
PMID- 9763115
TI - Peptide growth factors and signal transduction.
AB - Cell differentiation and proliferation are influenced by peptide growth factors.
These peptide molecules are important in maintaining the normal development and
growth of animal cells; in addition, they have been found to play a major role in
disease states. The role of growth factors in the development of arteriosclerosis
and intimal hyperplasia is of great interest to us as physicians taking care of
patients with peripheral vascular disease. Factors such as platelet-derived
growth factor (PDGF), fibroblast growth factor (FGF), insulin, insulin-like
growth factor-I (IGF-I), and transforming growth factors alpha and beta (TGF
alpha and beta) have been found to play important roles in controlling the
progression of cells in the cell cycle. Furthermore, various growth factors have
been found to influence the motility of cells, particularly vascular smooth
muscle cells (VSMCs).
PMID- 9763114
TI - Myointimal hyperplasia: basic science and clinical considerations.
AB - The mechanical injury caused by a bypass procedure or angioplasty of the coronary
or peripheral arteries can initiate and maintain the process of myointimal
hyperplasia. Myointimal hyperplasia is of great clinical importance. The
development of the hyperplastic lesion at the outflow anastomosis of a prosthetic
bypass or in autogenous saphenous vein bypass placed in the arterial system is
responsible for most bypass failures. It is also the primary cause of restenosis
after coronary angioplasty. Myointimal hyperplasia is a complex pathological
process of the vascular system characterized by an abnormal proliferation of
smooth muscle cells of the vascular wall. Proliferating smooth muscle cells
migrate to the subendothelial area and form the hyperplastic lesion, which causes
stenosis and obstruction of the vascular lumen. The pathogenesis of myointimal
hyperplasia remains under investigation. However, it has been established that
both mechanical and chemical factors may induce this process. Arterial injury is
believed to stimulate the production of growth factors, such as platelet-derived
growth factor (PDGF), which have been shown to stimulate the proliferation of
arterial smooth muscle cells and the formation of the hyperplastic lesion in the
vascular system. These growth factors and cytokines have been found to be
secreted by a variety of cells, including endothelial cells, macrophages,
platelets, and arterial smooth muscle cells. Blocking the effects of growth
factors such as PDGF or fibroblast growth factor (FGF), by the administration of
their antibodies, has been shown to limit the development of the hyperplastic
lesion. In this article, we begin with the basic physiology of myointimal
hyperplasia. We then address possible therapeutic considerations for the future.
PMID- 9763116
TI - Risk factors and their role in the diseases of the arterial wall.
AB - The leading cause of death and disability in developed nations is
atherosclerosis. Multiple risk factors, including hyperlipidemia, cigarette
smoking, diabetes mellitus, and hypertension, predispose to the development of
atherosclerosis. The mechanisms by which these risk factors exacerbate
atherosclerosis involve the potentiation of endothelial and smooth muscle cell
dysfunction as well as disturbances in coagulation. These mechanisms are
discussed in detail in this chapter. Understanding the pathophysiology of how
risk factors accelerate the progression of atherosclerosis will aid the clinician
in attempts to treat the atherosclerotic patient.
PMID- 9763117
TI - Arterial hemodynamics and wall mechanics.
AB - Arterial hemodynamics and wall mechanics are important considerations for the
vascular clinician for a number of reasons. Hemodynamics and wall mechanics both
have been shown to be affecters of disease formation. It is important for the
practicing vascular surgeon to know how disease affects both blood flow and wall
mechanics and to understand the consequence of hemodynamics on arterial
reconstructions. In this article, we summarize the basic concepts of arterial
hemodynamics and wall mechanics as they relate to the development of arterial
pathology. A few practical mathematical relationships and examples are provided
for both illustration and utilization. We also discuss the use of computer models
for the estimation of wall stresses in individual abdominal aortic aneurysms.
PMID- 9763118
TI - Vasomotor tone and the role of nitric oxide.
AB - Vasomotor tone is the end result of a complex set of interactions that control
relaxation and contraction of blood vessels. The critical role of nitric oxide
(NO) in modulating vasomotor tone has become increasingly apparent over the last
15 years. A phenomenal amount of resources have been invested in the study of
this simple molecule, and the volume of scientific literature that has resulted
is astounding. In this review, we discuss the pertinent physiology and
biochemistry of NO as it relates to the control of vasomotor tone. Methods of
measuring NO in basic science and clinical settings are outlined, and the
derangements of endothelial NO production and release (endothelial dysfunction)
in pathophysiologic and disease states are discussed. Finally, potential
therapies aimed at preserving endothelial function and augmenting NO production
also are reviewed.
PMID- 9763119
TI - The formation of aneurysms.
AB - Arterial aneurysms account for a significant proportion of the various diseases
treated by the vascular surgeon. Refinements of surgical technique have reduced
the morbidity and mortality, yet, we have no effective medical therapy to prevent
the growth of small aneurysms. Although the pathogenesis of aneurysmal disease
has received attention, the complex nature of the process has not been fully
elucidated. The emergence of new and refined techniques in the fields of
immunology, biochemistry, cell biology, and genetics has advanced the
understanding of the dynamic interactions within a diseased vessel. Although past
work was descriptive, investigators are now studying the role of the local
inflammatory infiltrates and the destructive proteolytic enzymes they produce and
regulate. The clinical observations we make regarding the familial tendency of
abdominal aortic aneurysms (AAA) underscores the importance of research directed
at identifying an aneurysm-related gene. As new pieces are added to the puzzle
and the picture of AAA pathogenesis becomes more clear, we can expect the
development of new therapeutic measures directed at controlling the critical
matrix changes, and thus the growth of small AAA, as well as screening methods
searching for AAA-associated genes.
PMID- 9763120
TI - Microvascular pathophysiology of skeletal muscle ischemia-reperfusion.
AB - Ischemia-reperfusion injury is a continuing challenge to vascular surgeons.
Microvascular factors and mechanisms underlying edema and compartment syndrome
provide a useful end point for analysis and planning of therapy. We review the
pivotal role of endothelium-leukocyte interactions and of cytokines in the
genesis of postischemic damage in muscle. Clinical considerations and future
directions based on research and practice are presented.
PMID- 9763121
TI - Gene therapy.
AB - Gene therapy for vascular disease is in the beginning stages. Each year
investigators are increasing our understanding of the molecular and cellular
biology of vascular disease and its complications. Our genes exert exquisite
control over the expressed molecular pattern that results in biological function
and pathology. Gene transfer techniques can be used to affect the pattern of gene
expression. Gene therapy is a powerful tool that will allow specific manipulation
of the genetic cascade that determines biological function. Gene transfer
techniques should help to define the molecular mechanisms involved in vascular
pathology, such as atherosclerosis and its complications. Currently, gene therapy
has only reached clinical trials, but this new technology will likely play a
major role in our treatment of vascular problems in the future. An understanding
of the significance of this new technology is important for both health care
providers and patients.
PMID- 9763122
TI - Improved detection of capripoxvirus in biopsy samples by PCR.
AB - A simple test based on the polymerase chain reaction (PCR) was used to detect
capripoxvirus DNA in tissue culture supernatants and biopsy samples. The identity
of the PCR products was confirmed by restriction enzyme analysis. The test has
greater sensitivity and good specificity compared to an antigen trapping enzyme
linked immunosorbent assay which uses a detector antibody raised against a
recombinant capripoxvirus-specific antigen. The reagents for the PCR-based test
are all available commercially and the test provides a valuable addition to the
current methods of virus detection.
PMID- 9763123
TI - Growth characteristics of fowl adenovirus type 8 in a chicken hepatoma cell line.
AB - Fowl adenoviruses, many of which appear to be non-pathogenic, are ubiquitous in
birds. In addition, the genome of these viruses is large, making them ideal
candidates for construction as vectors for foreign genes. Current methods to
cultivate fowl adenoviruses use primary cell cultures derived from embryonated
chicken eggs. In order to provide a more suitable culture method, the growth of
fowl adenovirus type 8 (FAdV-8) was investigated in CH-SAH, a continuous hepatoma
cell line. A one step growth curve demonstrated release of extracellular virus
beginning by 18 h p.i. and with a final yield about 100 fold higher than that in
chicken embryo liver cells. Viral DNA synthesis was first detected 8 h prior to
this. The CH-SAH cell line supported the production of progeny viruses similar to
the wild-type virus after being transfected with purified FAdV-8 DNA. This study
demonstrated that the continuous hepatoma cell line is an appropriate in vitro
host for FAdV-8.
PMID- 9763124
TI - PCR ELISA for the quantitative detection of Epstein-Barr virus genome.
AB - A highly sensitive and nonradioactive microplate hybridization assay for the
detection of Epstein-Barr virus (EBV)-specific polymerase chain reaction (PCR)
product was developed. The PCR product is labelled by adding digoxigenin-dUTP
directly to the reaction mixture and, after denaturation, is captured by a
microtitre plate coated with an extravidin-linked biotinylated probe. Captured
products are reacted with a peroxidase-conjugated anti-digoxigenin antibody and
detected using tetramethylbenzidine. The assay detected less than ten EBV genomes
in a background EBV-negative DNA of 0.75 microg and, when tested on clinical
samples, it was able to define the viral load in throat washings of patients with
acute infectious mononucleosis, immunosuppressed patients with HIV infection, and
rare normal individuals who shed the virus in the oropharynx.
PMID- 9763125
TI - Colourimetric PCR-based detection of monodon baculovirus in whole Penaeus monodon
postlarvae.
AB - The development of a nested polymerase chain reaction (PCR) assay is described to
detect low concentrations of monodon baculovirus (MBV) DNA from total Penaeus
monodon postlarval DNA. A modified DNA extraction procedure was also developed to
circumvent problems associated with co-purification of PCR inhibitors in total
DNA extracted from whole postlarvae. This method involved mechanical disruption
of frozen prawn material immediately followed by phenol extraction at high
temperature. An assessment of the sensitivity of the assay demonstrated detection
down to eight viral genome equivalents. The PCR was shown to be specific for MBV
DNA by not amplifying prawn DNA or DNA preparations of Baculovirus penaei (BP),
white spot baculovirus (WSBV), bennettae baculovirus and insect Autographica
californica nuclear polyhedrosis virus (NPV). A colourimetric method of PCR
product detection was used to simplify final analysis.
PMID- 9763126
TI - Development of a rapid and sensitive quantitative assay for rotavirus based on
flow cytometry.
AB - A very sensitive and accurate flow cytometry (FC) based method have developed to
quantitate rotavirus infection in MA104 cells. Confluent cell monolayers were
infected with serial dilutions of rotavirus SA11. After infection, the cells were
recovered with the aid of trypsin and then reacted with monoclonal antibody M60
(specific for the rotavirus outer capsid protein, VP7), followed by a second
antibody (anti-mouse IgG-FITC). A FACScan FC was used to estimate the number of
infected cells, as well as the level of infection. Viral infection was optimised
by varying the concentration of trypsin used in the maintenance medium. The FC
method enables many cells to be screened quickly for infectivity, and can detect
low levels of virus. This method can be adapted to monitor the presence of other
viruses in clinical and environmental samples without the need for prolonged
periods of adaptation to growth in tissue culture.
PMID- 9763127
TI - Recombinant Jembrana disease virus proteins as antigens for the detection of
antibody to bovine lentiviruses.
AB - Jembrana disease virus (JDV) is a recently identified bovine lentivirus causing
an acute severe disease syndrome in banteng cattle (Bos javanicus) and a milder
disease syndrome in Bos taurus cattle in Indonesia. The virus is closely related
genetically to the previously identified bovine lentivirus, bovine
immunodeficiency virus (BIV). Recombinant clones were produced which contained
the capsid (CA) and transmembrane (TM) subunits of the respective gag and env
open reading frames of JDV. The proteins were expressed as fusions to the
glutathione-s-transferase (GST) enzyme in Escherichia coli and purification was
achieved using affinity chromatography via immobilized reduced glutathione. The
soluble recombinant CA and TM antigens of JDV were reacted in western immunoblots
with both serum antibodies from JDV-infected Bos javanicus cattle and Bos taurus
cattle immunized with BIV. The recombinant CA protein of JDV reacted equally well
with both the JDV and BIV antisera. The recombinant TM protein of JDV also
reacted with antibody from the JDV infected cattle and with the BIV antisera. The
results indicated conservation of immunogenic epitopes of the CA and TM proteins
of the two viruses. The production of the recombinant proteins should enable the
development of rapid and sensitive serological tests for JDV and BIV, and tools
for further study of the immune response to JDV and the differential epidemiology
of JDV infections in cattle.
PMID- 9763128
TI - Comparative detection of classical swine fever virus in striated muscle from
experimentally infected pigs by reverse transcription polymerase chain reaction,
cell culture isolation and immunohistochemistry.
AB - Classical swine fever (CSF) is a highly contagious viral disease, which can be
transmitted by CSFV-contaminated swill. In 1993, four CSF outbreaks in
Switzerland were caused presumably by feeding pigs with improperly heated swill.
The aim of the investigations was to find a suitable method for CSFV detection in
striated muscle samples of infected pigs in order to allow routine testing of
meat for virus contamination. The sensitivity of virus detection in striated
muscle was compared with the detection in target organs. Using reverse
transcription polymerase chain reaction (RT-PCR), cell culture isolation and
immunohistochemistry on samples from 14 experimentally infected pigs, CSFV was
detected in target organs of ten, and in striated muscle of six pigs,
respectively. Overall, only 58% of muscle samples from CSFV-positive animals were
positive by RT-PCR and 40% by virus isolation in cell culture, whereas the virus
was detected in target organs of these pigs. Virus detection from striated muscle
was primarily successful in severely diseased animals infected with highly
virulent CSFV strains. It is concluded that striated muscle is not suitable for
sensitive CSFV detection, and additional organs have to be examined for reliable
diagnosis.
PMID- 9763129
TI - Comparison of RNA hybridization, hemagglutination assay, titration of infectious
virus and immunofluorescence as methods for monitoring influenza virus
replication in vitro.
AB - Rapid and sensitive methods for the monitoring of influenza virus replication in
vitro are needed to address several research questions. Four methods based on
different principles were compared: the hemagglutination (HA) assay, the
measurement of virus infectivity titers in culture supernatants, the enumeration
of infected cells by immunofluorescence and RNA hybridization techniques using
digoxigenin (DIG) labeled RNA probes. To this end, MDCK cells were infected at
different multiplicities of infection (moi) with a recent influenza A virus
(A/Netherlands/18/94 H3N2) and the kinetics of virus replication were monitored
with these four assays. At high moi, virus released into the culture supernatant
of infected cells was detected by the HA assay 12 h post infection, whereas at
lower moi (< or = 0.01) the first HA activity was not detected before 24 h post
infection. The measurement of infectious viruses in the culture supernatant
proved to be more sensitive, since 4-12 h post infection newly produced virus was
detected depending on the moi used. This finding was in agreement with results
obtained by the immunofluorescence assay using an antibody preparation specific
for the nucleoprotein: single infected cells could be detected as early as 4 h
post infection. At this time point, positive signals were also obtained when
mRNA/cRNA specific hybridization was carried out for the NP gene segment, but not
for viral NP RNA or RNA specific for the hemagglutinin, which were only detected
at later time points after infection. Thus, besides direct measurement of
infectious virus and immunofluorescence, RNA hybridization proved to be a
sensitive assay for monitoring influenza virus replication in vitro.
PMID- 9763130
TI - The GPRIME package: computer programs for identifying the best regions of aligned
genes to target in nucleic acid hybridisation-based diagnostic tests, and their
use with plant viruses.
AB - The GPRIME (Group PRIMEr design) programs examine aligned sets of gene sequences
to discover homologous regions to be targeted in diagnostic tests. The core
program moves a 'window' over the aligned sequences and calculates, at each
window position, a 'redundancy value', namely the number of sequences that would
represent all permutations of the variable sequence positions within that window.
Regions with minimal redundancy values may then be targeted in diagnostic tests
based on oligonucleotide hybridisation. The likely specificity of tests targeting
such regions can be assessed by searching the international databases with those
regions using FASTA. The GPRIME programs, which include programs for designing
primers to distinguish between two sub-sets of a group of aligned sequences, can
be obtained from http://life.anu.edu.au/software.html. We have used GPRIME to
design redundant primers for RT-PCR tests to detect all potexviruses and
tobamoviruses, and then used these, together with a previously reported pair of
primers for the Potyviridae, to screen some Australian orchid collections. Two
orchid viruses previously reported from Australia were found; cymbidium mosaic
potexvirus was common, but odontoglossum ringspot tobamovirus was not. In
addition the recently described ceratobium mosaic potyvirus was found to be
common, and three other novel potyviruses were also found.
PMID- 9763131
TI - A simplified immunoassay based on measles virus recombinant hemagglutinin protein
for testing the immune status of vaccinees.
AB - Simplified tests based on recombinant antigens are considered to be important for
monitoring immunity against measles virus (MV). The hemagglutinin protein (H) is
the main target for neutralising and protective antibodies. We produced a
recombinant MV-H protein, in a high-yield mammalian expression system based on
the Semliki Forest virus replicon. The antigenicity of this recombinant protein
was investigated with monoclonal antibodies and its suitability for measuring the
immune status of vaccinees was tested in a large cohort by ELISA (H-ELISA). The
results were evaluated against neutralisation (NT) and hemagglutination
inhibition (HI) titers and MV-specific IgG measured in a commercial whole-virus
based ELISA (MV-ELISA, Enzygnost). The H-ELISA correlated better with HI (r=0.78)
and NT titers (r=0.80), than the MV-ELISA (HI, r=0.58; NT, r=0.59). In contrast
to the MV-ELISA, the H-ELISA detected no false-positive sera (P < 0.02) and the
number of false-negative sera was significantly lower in the H-ELISA than in the
MV-ELISA (4/378 vs. 15/378; P < 0.025). The performance of the H-ELISA did not
deteriorate significantly when, instead of background corrected net values,
uncorrected raw O.D. values of the H-antigen were considered, or when early time
points (30 min) were evaluated. These results demonstrate that the recombinant H
ELISA detects efficiently non-immune individuals among vaccinees, despite their
relatively low MV-antibody levels. A simplified format with single value
measurements did not result in loss of sensitivity or specificity and its
performance compared favorably with commercial ELISAs based on whole virus.
PMID- 9763133
TI - A new and simple method for concentration of enteric viruses from water.
AB - A new type of electropositive filter media particle was tested to adsorb
bacteriophage f2 and enteric viruses from tap water. 3 x nutrient broth (pH 7.2)
was used to elute the adsorbed viruses, and the eluate was reconcentrated by
polyethylene glycol (Mw 6000) precipitation with a final concentration of 10%
(wt./vol.). The adsorption of bacteriophage was reliable and efficient, and not
affected by the pH value, temperature, turbidity and organic materials in water.
This method gave a recovery of Polio 1 virus 96.0% for small-volume tap water;
88.7% for large-volume water; and gave a comparable recovery of HAV, Coxsackie B3
and Echo 7 from tap water. The concentration method need not acidify virus
containing water, add exogenous multivalent cation salts, or require expensive
equipment.
PMID- 9763132
TI - Human monoclonal anti-HCMV neutralizing antibody from phage display libraries.
AB - Human cytomegalovirus (HCMV) infection in immunocompromised patients causes
considerable morbidity and mortality. Although ganciclovir prophylaxis reduces
the incidence of HCMV disease, severe side effects raise serious problems. Thus,
the development of new strategies for prophylaxis are clearly needed, and human
monoclonal antibodies offer a potential alternative. We describe the cloning,
using the phage display system, of a recombinant human Fab fragment against HCMV.
A phage display library with 4 x 10(6) clones was panned three times against
lysates of HCMV-infected cells, and screened by ELISA. Of six antigen-binding
clones, one monoclonal antibody reacted strongly to HCMV. In immunostaining
analysis, this Fab was able to stain HCMV-infected cells from 24 h post-infection
(pi) through to 96 h pi, but not at 6 h pi. In the presence of cytosine
arabinoside, HCMV-infected cells were not stained, even at 24 h pi. These results
indicate that an HCMV protein that was recognized by the Fab was synthesized in
the late phase of infection. In addition, this Fab exhibited neutralizing
activity: at 1 microg/ml it reduced HCMV plaque formation by 50%. The Fab was
able to neutralize three HCMV strains, but it did not neutralize HSV-1 or -2
infection.
PMID- 9763134
TI - Differentiation among isolates of prunus necrotic ringspot virus by transcript
conformation polymorphism.
AB - A method based on differences in electrophoretic mobility of RNA transcripts made
from polymerase chain reaction (PCR) products was used for differentiation among
virus isolates. A T7 RNA polymerase promoter was attached to amplified prunus
necrotic ringspot virus (PNRSV) sequences by PCR. The PCR products then served as
a template for transcription. Single-stranded transcripts originated from
different PNRSV isolates varied in electrophoretic mobility in polyacrylamide
gels, presumably because of transcript conformation polymorphism (TCP). This
procedure was applied for the differentiation of PNRSV isolates.
PMID- 9763135
TI - Total chemical synthesis of the 3' untranslated region of the hepatitis C virus
with long oligodeoxynucleotides.
AB - Hepatitis C Virus (HCV) is the major causative agent of chronic hepatitis. Since
it has been difficult to obtain full-length cDNA clones of HCV including the 3'
untranslated region (UTR) that give rise to replication competent virus, we
generated the 3'UTR by a modified protocol of total chemical synthesis (TCS) with
overlap-extension-PCR using four long oligodeoxynucleotides. A synthetic cDNA
fragment of about 340 nucleotides (nt) in length was generated, subcloned and
sequenced. This approach represents a rapid and easy alternative to RT-PCR from
infectious serum and may be a highly valuable method to generate partial cDNA
clones of HCV and other viruses including defined variants.
PMID- 9763136
TI - Dysfunctional filtering blebs.
AB - Guarded filtration surgery, is commonly used to control the intraocular pressure
(IOP) in glaucomatous patients. Filtration surgery lowers the IOP by creating a
fistula between the inner compartments of the eye and the subconjunctival space
(i.e., filtering bleb). There are several options to improve the function of
filtering blebs and to prevent their failure. However, improvement of IOP control
after guarded filtration procedures is associated with a higher frequency of bleb
related complications. Early (e.g., bleb leak, excessive filtration, flat
anterior chamber, filtration failure) and late (e.g., bleb leak, excessive
filtration and hypotony, symptomatic blebs, bleb encapsulation, filtration
failure, bleb infection) complications associated with filtering procedures
should be managed adequately to prevent further problems. Techniques to improve
the function of filtering blebs and to treat postoperative complications have
progressed over the past decade.
PMID- 9763137
TI - Conjunctival melanoma in the black population.
AB - Melanoma of the conjunctiva is a rare, unilateral malignancy primarily affecting
middle-aged whites; the annual average age-adjusted incidence rate is 0.012 per
100,000 population. Although conjunctival melanoma in the black population is
extremely rare, cases have been reported. Melanoma of skin in blacks has a
predilection for nonsun-exposed, nonpigmented sites such as mucous membranes,
palms, and soles. Primary acquired melanosis may lead to the development of
melanoma even in blacks. Primary acquired melanosis in the black population may
be difficult to differentiate from racial melanosis clinically and
histopathologically. Early diagnosis through awareness and education can help
improve the survival of black patients with conjunctival melanoma.
PMID- 9763139
TI - Surgical correction of moderate myopia: which method should you choose? I. Radial
keratotomy will always have a place.
AB - This set of "Viewpoints" articles examines the relative merits of radial
keratotomy (RK), photorefractive keratectomy (PRK), and laser assisted in-situ
keratomileusis (LASIK). Drs. Rowsey and Morley review advances in RK techniques,
long-term results, and complications, and explain why RK will remain a viable
method for correction of moderate myopia, notably its minimal cost. Drs. Steinert
and Bafna review both PRK and LASIK, discussing techniques and results and
comparing their advantages and disadvantages with each other and with RK. Dr.
Dutton, as "Viewpoints" section editor, summarizes clinical, technologic, and
economic aspects of all three techniques, concluding that all will find a place
among refractive surgeons for some time to come.
PMID- 9763138
TI - Age-related macular degeneration: a review of experimental treatments.
AB - Age-related macular degeneration (AMD) is the leading cause of irreversible
visual loss in the USA. Laser photocoagulation of choroidal neovascular membranes
(CNVMs) in exudative AMD is currently the only well-studied and widely accepted
treatment modality. It is beneficial for only a small minority of patients who
show well-demarcated "classic" CNVMs, and it destroys normal retinal tissue,
creates a scotoma, and is associated with an unacceptably high CNVM persistence
and recurrence rate. Consequently, investigators have attempted to develop new
modalities for treatment of CNVMs. These treatment modalities can be grouped into
four major categories: photodynamic therapy; pharmacologic inhibition of CNVM
formation with antiangiogenic agents; surgical intervention, including excision
of subfoveal CNVMs; and radiation therapy. All of these experimental treatment
modalities are directed toward destroyiing CNVMs, the end result of the exudative
process, and all have limitations. The ideal treatment of the future must be
based on the pathogenesis of the disease at a stage well before CNVMs develop.
Investigations in nonexudative AMD are currently focusing on several major areas.
Epidemiologic factors, such as genetics, sunlight, and nutrition, are being
evaluated in several large studies, including the Age-Related Eye Disease Study,
with the possibility of ultimately limiting the risk of AMD through behavior
modification. Laser treatment of drusen is being evaluated as a means of limiting
the risk of CNVM formation, although mixed results have been reported in the
small number of studies to date. Choroidal perfusion abnormalities have been
described in AMD, and some investigators postulate that altering blood flow may
limit the risk of CNVM formation. No perfusion-treatment trials have been
completed to date.
PMID- 9763140
TI - Unilateral eyelid ptosis and a red eye.
AB - A 56-year-old woman presented with a unilateral ptosis induced by a nonembedded
soft contact lens of approximately 2 years' duration. The unilateral ptosis most
likely resulted form localized inflammation and the physical presence of the soft
contact lens. The patient's symptoms resolved completely after double lid
eversion and lens removal.
PMID- 9763141
TI - A remembrance of Edward Vail Lapham Brown.
AB - E. V. L. Brown's ophthalmic legacy is based on his clinical research
accomplishments, including his research centered around the causes of uveitis and
his exhaustive studies on refractive errors in childhood, as well as his devotion
to teaching, training a corps of carefully trained observers who were meticulous
in their diagnostic techniques and surgical skills. This article presents a brief
history of E. V. L. Brown's life and recreates what it was like to be a resident
under this distinguished ophthalmologist at the University of Chicago Eye Clinic
50 years ago.
PMID- 9763142
TI - Strain rate as a controlling influence on adaptive modeling in response to
dynamic loading of the ulna in growing male rats.
AB - To test the hypothesis that the rate of change of strain to which a bone is
subjected is an important determinant to the subsequent functionally adaptive
modeling response, the ulnae of growing male rats were subjected to dynamic axial
loading in vivo for a short period each day over 2 weeks. Due to the longitudinal
curvature of the ulna, such axial loading leads to both compression and bending.
The left ulna in three groups of rats was loaded cyclically between 1 and 20 N in
a trapezoidal pattern to produce dynamic, longitudinal compressive strains of
0.004 (-4000 microstrain) at the medial midshaft with one of three strain rates:
low (+/-0.018 sec(-1); n = 7); moderate (+/-0.030 sec(-1); n = 7); and high (+/
0.100 sec(-1); n = 8). These strain rates span the range recorded from strain
gauges bonded to the bone at this site during a variety of normal activities. At
the end of the experiment, the loaded ulnae were slightly, but significantly,
shorter than their contralateral controls (2.7% to 5.6% mean change in length; p
< 0.0001). This effect was most marked at lower strain rates, associated with an
increased load-bearing time. The pattern of adaptive modeling along the bone
shaft was similar for all groups, each showing a reduced rate of periosteal
expansion proximally, and increased periosteal new bone production distally. This
distal increase was achieved through enhanced periosteal bone formation on the
lateral (tension) cortex, and arrest of resorption, with conversion to formation
on the medial (compression) surface. The modeling response to axial loading
therefore involves complex location-dependent increases and decreases in both
formation and resorption. The high-strain-rate group demonstrated a 54% greater
osteogenic response than the moderate-strain-rate group, which in turn showed a
13% larger response than the low-strain-rate group. Rate of strain change is
therefore a major determinant of the adaptive osteogenic/antiresorptive response
to mechanical load. Across the physiological range, a high rate of strain change
provides a greater osteogenic stimulus than the same peak strain achieved more
slowly.
PMID- 9763143
TI - Validation of quantitative backscattered electron imaging for the measurement of
mineral density distribution in human bone biopsies.
AB - The measurement of bone mineral density (BMD) using X-rays is usually employed to
monitor the mineral content in a given portion of bone. However, this method
cannot differentiate between changes in bone volume or in degree of
mineralization of the bone matrix. In contrast to BMD, bone mineral density
distribution (BMDD), as measured on bone sections by quantitative backscattered
electron imaging (qBEI), is able to distinguish differences in the degree of
mineralization. For routine clinical research, we have validated the method of
calibration and standardization of the backscattered electron (BE) signal. Carbon
and aluminum were used as reference materials for BE gray levels and osteoid and
apatite for calcium concentration. Experiments were performed to get knowledge
about precision (intraassay variance-instrumental stability and interassay
variance-reproducibility) and accuracy (standardization) of this method as well
as the biological variance (intraindividual and interindividual) in human bone.
On transiliac biopsies or necropsies from 20 individuals having had accidental
death (13 females, 7 males, age 30-85 years) BMDD measurements were conducted.
The patients' medical history as well as the histomorphology of these bones
showed no evidence of metabolic bone disease. For instance, the standard
deviations of the weighted mean calcium concentrations were <0.3%, <0.4%, <0.9%,
and <2.6% of the mean for the intraassay, interassay, intraindividual, and
interindividual variations, respectively. In addition, a mean BMDD histogram for
transiliac bone specimens was calculated from the 20 aforementioned individuals.
The method used allows detection of the degree of mineralization independently
from the actual bone volume, a result that seems to be of special interest in the
assessment of the effect of treatments for osteoporosis. The power of this
technique is demonstrated by using bone from a patient with a metabolic bone
disease. In this case of osteomalacia due to celiac disease, the mean calcium
concentration in the bone matrix was reduced by 19.3% as compared with normal.
PMID- 9763144
TI - Parathyroid hormone induces interleukin-6 heterogeneous nuclear and messenger RNA
expression in murine calvarial organ cultures.
AB - The cytokine, interleukin-6 (IL-6), is produced by osteoblasts and may in part
mediate parathyroid hormone (PTH)-stimulated bone resorption. The goals of the
present study were: (1) to examine PTH induction of IL-6 expression in 7-day-old
mouse calvarial organ cultures; (2) to assess the role of intracellular signaling
pathways in this model; and (3) to determine whether PTH regulates IL-6
expression by a transcriptional mechanism. Northern blot analysis of calvarial
RNA showed that PTH(1-34) at 0.1-100 nmol/L induced IL-6 mRNA at 0.5 h with a
peak at 2 h. Forskolin at 10 micromol/L and 8-bromocyclic-AMP at 3 mmol/L also
induced IL-6 mRNA with a peak at 2 h. Phorbol myristate acetate induced IL-6
expression, whereas ionomycin and PTH(3-34) amide, an N-terminal-truncated PTH
analog that has reduced ability to activate the cAMP-PKA pathway, were much less
effective. PMA pretreatment of calvariae greatly blocked IL-6 mRNA induction by a
subsequent dose of PMA and decreased induction by PTH and forskolin to a much
lesser extent. A reverse-transcriptase polymerase chain reaction (RT-PCR) assay
was used to measure IL-6 heterogeneous nuclear RNA (hnRNA) and mRNA. A 5' primer
spanning exons 1 and 2 and a 3' primer complementary to exon 5 of the murine IL-6
gene were used to detect IL-6 mRNA as a 638 bp product. A 5' primer corresponding
to intron 4 of the murine IL-6 gene and the 3' primer were used to detect IL-6
hnRNA as a 370 bp product. RT-PCR of total calvarial RNA showed that the
induction of IL-6 hnRNA by PTH and other agonists was similar to their induction
of IL-6 mRNA. These data support the conclusion that PTH transcriptionally
induces IL-6 gene expression in murine calvarial organ cultures mainly through
the cAMP-PKA signaling pathway.
PMID- 9763145
TI - Effect of clodronate treatment on established bone loss in ovariectomized rats.
AB - The ability of clodronate to prevent bone loss and weakening of bone strength was
studied in adult rats with established osteopenia. Six-month-old female Sprague
Dawley rats were randomized into 13 groups. One group was killed at the start of
the study, nine groups were ovariectomized (ovx), and three groups sham-operated
(sham). After 4 months, the ovx rats were given either clodronate or vehicle
subcutaneously (s.c.), once a week for 3 or 6 months, the cumulative doses of
both dosing regimens being 36, 84, and 300 mg/kg. Clodronate reduced the increase
in bone turnover as evidenced by serum osteocalcin and urinary deoxypyridinoline.
Cancellous bone loss was more severe in distal femur than in lumbar vertebral
body already at 4 months after ovx. Cortical osteopenia of femoral middiaphysis
was significant at 7 and 10 months after operation and was in accordance with the
impaired bending strength of the femoral shaft. In the tibia, the bending
strength was, by contrast, increased at each timepoint after ovx. In distal
femur, higher values of cancellous bone volume (BV/TV) were found after 6 months
of clodronate treatment than in ovx/vehicle-treated rats. In lumbar vertebrae,
only the lowest dose of clodronate slightly counteracted the ovx-induced further
decrease in BV/TV, but reduced, at all dosages, the impairment of lumbar
vertebral compression strength. The maximum load of femoral neck did not differ
between vehicle-treated ovx and sham groups after clodronate treatment, but
clodronate reduced the weakening of femoral shaft. A further increase in the
bending strength of the tibia was found after clodronate treatment. There was a
positive correlation between bending strength and ash weight in both the tibia
and the femur. Histomorphometry further showed that long-term use of clodronate
does not impair bone mineralization or affect modeling-dependent bone formation.
In conclusion, clodronate treatment clearly slows down the progress of bone loss
and prevents further weakening of bone strength in femoral shaft and vertebrae,
even though it cannot completely reverse the effects of ovariectomy-induced
changes in established osteopenia.
PMID- 9763146
TI - Growth hormone increases vertebral and femoral bone strength in osteopenic,
ovariectomized, aged rats in a dose-dependent and site-specific manner.
AB - The aim of the study was to assess the effect of growth hormone (GH) as
restorative therapy in an aged, ovariectomized rat model with established
osteopenia. The study was planned as a dose-response study, and four different
skeletal sites were investigated by mechanical testing and measurements of bone
mass and dimensions. Twelve-month-old virgin F344 rats were divided into eight
groups with ten animals per group: (1) sham operated (sham); (2) ovariectomized
(ovx); (3) sham + solvent vehicle (sv); (4) ovx + sv; (5) ovx + GH 50 microg/kg
body weight/day; (6) ovx + GH 1.25 mg/kg body weight/day; (7) ovx + GH 2.5 mg/kg
body weight/day; and (8) ovx + GH 5.0 mg/kg body weight/day. Groups 1 and 2 were
killed after 3 months to establish that bone loss had occurred due to ovx. One
month later, the remaining groups began 3 months of treatment, at the end of
which the animals were also killed. The effects of ovariectomy (ovx) and GH
therapy were measured at four skeletal sites: lumbar vertebrae; femoral
diaphysis; femoral neck; and distal femoral metaphysis. Ovariectomy induced a
significant loss of bone strength at all sites apart from the femoral neck. The
loss was most pronounced at the distal femoral metaphysis. GH was able to reverse
the ovx-induced loss of strength at the vertebral site in a dose-dependent
manner. At the femoral diaphyseal site, GH not only reversed the ovx-induced
changes but increased load values significantly above sham level. However, at the
distal femoral metaphysis, which is dominated by cancellous bone, only partial
reversal was seen after GH treatment. The lowest GH dose had no significant
effect at any site tested. We conclude that GH treatment can reestablish
vertebral bone loss due to ovariectomy in a dose-dependent manner. The
restorative effect is only partial at the distal femoral metaphysis even at a
high dose. At skeletal sites with less pronounced ovx-induced bone loss (femoral
neck and diaphysis), GH treatment increased bone strength to sham level or above
sham level. Therefore, the effect of ovariectomy is dependent upon the skeletal
site investigated, and the effect of GH treatment is dependent on both the
skeletal site and the size of the ovx-induced bone loss at this site.
PMID- 9763147
TI - Prednisolone prevents decreases in trabecular bone mass and strength by reducing
bone resorption and bone formation defect in adjuvant-induced arthritic rats.
AB - We examined the effects of prednisolone (PSL) administration in normal female
Sprague Dawley rats and adjuvant-induced arthritic rats at the age of 6 weeks.
Rats were intramuscularly injected with PSL twice a week at doses of 0 (control),
10, 30, 90, or 270 mg/kg body weight (b.w.). In the normal rats, serum
osteocalcin level at 14 days and serum carboxyterminal pyridinoline cross-linked
telopeptide of type 1 collagen (1CTP) level at 28 days in the 270 mg/kg dose
group was lower than the respective value in control animals. The BMC and the
trabecular bone formation rate (BFR/BS) of the lumbar body (L-4) in the 270 mg/kg
dose group at 14 and 28 days were significantly lower than the values in the
control rats. In the arthritic rats, however, serum osteocalcin levels in the PSL
treated groups did not differ compared with arthritic controls. The serum 1CTP
levels in all of the PSL-treated groups were significantly reduced at 28 days.
The age-dependent increases in the L4 BMC, BMD, and L-3 ultimate compressive load
values were maintained. The BFR/BS values in the 90 mg/kg and 270 mg/kg dose
groups were significantly higher than those in the arthritic control rats. The
trabecular osteoclast number and surface values in all of the PSL-treated groups
were significantly lower than the values in arthritic controls. These data
demonstrate that PSL administration prevented reduction in bone mass and strength
of the lumbar trabecular bone in adjuvant-induced arthritic rats by reducing the
increase in bone resorption and the decrease in bone formation at both the local
and systemic levels.
PMID- 9763148
TI - Effects on bone of oral hormone replacement therapy initiated 2 years after
ovariectomy in young adult monkeys.
AB - The purpose of this study was to determine the effects of oral estrogen
replacement therapy with conjugated equine estrogens (CEE), alone or in
combination with continuous medroxyprogesterone acetate (MPA), on lumbar spine
bone mineral content (BMC) and density (BMD) and on serum chemistries in
ovariectomized cynomolgus monkeys when therapy is initiated following a 2 year
hypoestrogenic period. Study design was done in the form of a randomized, placebo
controlled, nonhuman primate paraclinical trial. Monkeys were subjects in an
experiment designed to study the effects of a lipid-lowering diet combined with
hormone replacement therapy on atherosclerosis. Initially, they were
ovariectomized and fed a high-fat diet for 24 months. They were then were
allocated to three treatment groups by stratified randomization and were fed a
diet containing reduced dietary fat for an additional 28 months. Treatment groups
consisted of: (1) an untreated group (ovx, n = 24); (2) a CEE-treated group (CEE,
n = 19); and (3) a CEE plus continuous MPA group (CEE + MPA, n = 20). Lumbar
spine BMC and BMD values were measured by dual-energy x-ray absorptiometry at
baseline and 4, 10, 16, 22, and 28 months of treatment. Serum chemistries were
relevant to bone metabolism at 22 and 28 months. Rates of gain in BMC and BMD
were greater (p < 0.05) in hormone-supplemented animals (groups 2 and 3) than in
untreated ovx animals during the first 16 months of treatment, resulting in
increased BMC and BMD measurements in these groups. Serum markers of bone
metabolism were significantly lower (p < 0.05) in the hormone-treated groups
(groups 2 and 3) compared with ovx animals after 22 and 28 months of treatment,
indicating reductions in bone turnover rate. Oral estrogen replacement with CEE
at doses similar to those taken by women leads to significantly increased BMC and
BMD in monkeys, even when therapy is begun 2 years after ovariectomy. Most of the
increase occurred during the first 16 months of treatment. The addition of MPA to
the CEE regimen provided no additional benefit.
PMID- 9763149
TI - Allelic variation at the interleukin-1 receptor antagonist gene is associated
with early postmenopausal bone loss at the spine.
AB - Genetic factors play an important role in determining bone mineral density (BMD)
in later life, with the genetic influence mediated through effects on both peak
mass and on age- and menopause-related bone loss. At menopause there is an
increase in the production and activity of various cytokines and growth factors
within the bone microenvironment. The activity of interleukin-1 (IL-1), a
powerful stimulant of osteoclastic bone resorption, is increased in estrogen
deficient states with increased production of IL-1 and inhibition of the IL-1
receptor antagonist (IL-1ra). Treatment with IL-1ra blocks the bone loss
associated with ovariectomy in animals and the IL-1 receptor antagonist gene (IL
1RN) is therefore a potential candidate gene for the regulation of postmenopausal
bone loss. We examined the relationship between annual rates of change in BMD
over 5 years and an 86 bp variable number tandem-repeat polymorphism of the IL
1RN gene in 108 early postmenopausal women. All women were within 5 years of a
natural menopause at the study's onset, healthy, and not on hormone replacement
therapy or other medication known to affect bone metabolism. BMD was measured
annually over the 5 year study period at the lumbar spine and femoral neck using
dual-energy X-ray absorptiometry. Three alleles were identified (A1 = 4 repeats,
A2 = 2 repeats, A3 = 5 repeats), with five genotypes observed: A1A1 (41.7%), A1A2
(45.4%), A2A2 (6.5%), A1A3 (2.8%), and A2A3 (3.7%). For analysis, alleles were
collapsed into a biallelic system grouping the A1 and A3 alleles. There was no
significant relationship between the IL-1RN genotypes and baseline bone mass at
either the spine or hip. IL-1RN genotype was significantly associated with annual
rates of change in spinal bone mass (p < 0.05), and this finding remained
significant after adjustment for age, weight, and baseline BMD. Carriage of at
least one copy of the A2 allele was associated with reduced bone loss at the
spine (mean change in BMD +/- SD: -0.81 +/- 1.46%/year) when compared with
noncarriage of the A2 allele (mean change -1.38 +/- 1.48%/year), p = 0.05. We
therefore conclude that allelic variation at the IL-1RN locus is associated with
differential rates of early postmenopausal bone loss at the spine. Further
research will be required to clarify the mechanisms underlying these findings and
to determine whether this association translates into a significant long-term
effect on BMD and fracture in later life.
PMID- 9763150
TI - Three-dimensional confocal images of microdamage in cancellous bone.
AB - The accumulation of microdamage in bone may contribute to loss of bone quality in
osteoporosis, and the role of microdamage in the etiology of fatigue fractures is
unknown. Microdamage created during testing, ex vivo, can increase the fragility
of bone by decreasing the load necessary to cause fracture. Microdamage can also
accumulate in vivo, but its influence on bone fragility is unknown. To date,
stained microcracks are the only criteria to have been correlated with bone
mechanics, leaving the influence of ultrastructural damage on bone fragility open
for scrutiny. Staining en bloc has identified three morphological features in the
tissue, discrete microcracks, cross-hatch staining, and diffuse staining. The
relationship between these features and their identification as microdamage
remains equivocal. The purpose of this study was to investigate the three
dimensional nature of microdamage in cancellous bone and also to describe stained
microcracks, cross-hatch staining, and diffuse staining and to determine whether
they all relate to microdamage in bone. Laser scanning confocal microscopy that
provides improved spatial resolution over bright-field microscopy was used to
visualize bone damage. It was found that crack surface density was highly
correlated with crack density (r = 0.95, p < 0.0001), suggesting that the crack
surface of preexisting cracks increases as new cracks are formed or
submicroscopic cracks become visible under bright-field microscopy. Cross-hatch
staining and diffuse staining included ultra-microcracks about 10 microm in
length. The ultra-microcracks in cross-hatch staining were organized in bands and
surrounded by diffuse staining. This study demonstrates that damage in bone
occurs over a wide range and that discrete microcracks, cross-hatch staining, and
diffuse staining are all indicative of bone damage. The diffuse staining still
evident in association with the ultra-microcracks seen in cross-hatch staining
and diffuse staining is probably due to damage at a still smaller scale than we
have been able to investigate.
PMID- 9763152
TI - Comparison of two methods for measuring orientation.
AB - At the Department of Dental Radiology of ACTA, the line fraction deviation (LFD)
method was developed to measure orientation on radiographic trabecular patterns.
This article explains the measurement of the LFD index of orientation in a
downscaled model. When investigations began to produce noteworthy results, the
need for deeper understanding of the method and the resulting diagrams increased.
Because it had previously been applied on rather complex patterns originating
from bone it seemed worthwhile to study simpler images as well, which might yield
a more intuitive understanding of the diagrams. Moreover, it seemed useful to
compare the new LFD method with the well-accepted mean intercept length (MIL)
method. Fifty images originating from cancellous bone structures and 25 drawings
were analyzed. The results show that the MIL method tends to produce ellipses
(not only on images originating from bone), and also that the LFD method is more
sensitive to anisotropy.
PMID- 9763151
TI - Bone loss in Great Britain and Japan: a comparative longitudinal study.
AB - Hip fracture incidence is lower in Japan than in the West. Although differences
have been found in peak bone mass and hip geometry between white and Japanese
populations, these do not fully explain the difference in hip fracture rates.
Variation in the rates of involutional bone loss may be an additional
contributing factor. We address this issue in a prospective epidemiological study
comparing bone loss rate among elderly people in Britain and Japan. Two
population-based studies of bone loss rate in a British and a Japanese cohort
were performed. Annual bone loss rates were obtained for 172 Hertfordshire men
and 143 Hertfordshire women of mean age 66 years, and a questionnaire
administered to obtain information on known confounding lifestyle factors. Eighty
six Japanese men and 90 Japanese women of mean age 69 years completed a similar
study in Taiji, Japan. British men and women were heavier than Japanese men and
women. Differences in lifestyle were also evident; the British men were less
likely to smoke and the women more likely to consume alcohol than their Japanese
counterparts. The British population also spent more time walking outdoors.
Statistically significant differences between the two populations were apparent
in baseline bone mineral density at lumbar spine (p < 0.05) and trochanter (p <
0.001) in men and women with Japanese subjects having lower values. There were
also significant differences in bone density at the femoral neck (p < 0.001)
between British and Japanese males. Men gained bone at the lumbar spine over the
follow-up period in both populations. Bone loss rates were generally greater in
the British female population than in Japanese women: the difference was
statistically significant at the femoral neck (p < 0.05) and femoral trochanter
(p < 0.001). These differences all remained significant after adjustment for
differences in age between the two populations. Japanese subjects appear to have
lower peak bone mass, but slower bone loss rates in later life than their
European counterparts. These differences in bone loss rate help to explain the
relatively low hip fracture rates found in Japan.
PMID- 9763153
TI - Declining health care provision to adolescents and the need for considering
culturally competent interventions.
PMID- 9763154
TI - Pediatricians' approach to the health care of lesbian, gay, and bisexual youth.
AB - The present study investigates the complex physician-patient relationship between
pediatrician and lesbian, gay, or bisexual youth. Sixty pediatricians completed
the questionnaire. The respondents' answers indicated a need and desire for
further training of pediatricians about the health care of these youth.
PMID- 9763155
TI - Access to health care for Latina adolescents: a critical review.
PMID- 9763157
TI - Adolescent health care experience of gay, lesbian, and bisexual young adults.
AB - METHODS: Subjects were 102 self-identified gay, lesbian, and bisexual youth aged
18-23 years. A confidential self-administered survey elicited demographic
information, sexual orientation information, health care experiences, subjects'
understanding of medical confidentiality during ages 14-18 years, and their
suggestions for improving care to gay and lesbian adolescents. RESULTS: Two
thirds of subjects never discussed sexual orientation with their provider but
reported a desire to do so. Fewer than one-half of subjects remembered being
informed about their right to medical confidentiality; those who reported being
so informed were three times more likely to have discussed their sexual
orientation with their provider. Over 70% of subjects who reported not being
informed about their right to medical confidentiality stated that they would have
been more likely to discuss sexual orientation with their provider had they been
so informed. Only 13 of subjects had disclosed their sexual orientation to their
health care providers. Of these, only half of the males received information on
human immunodeficiency virus prevention. CONCLUSIONS: Health care providers may
be failing to fully address issues of confidentiality and sexual orientation with
adolescents, despite a decade of increased information on adolescent
homosexuality.
PMID- 9763156
TI - Condom use by Hispanic and African-American adolescent girls who use hormonal
contraception.
AB - PURPOSE: The purpose of the present study was to examine condom use by teens who
use hormonal contraceptives [i.e., Depo-Provera, Norplant, or oral contraceptives
(OCs)]. METHODS: This is a cross-sectional study of 578 Hispanic and African
American female adolescents between the ages of 12 and 21 years who came to a
reproductive health care clinic. A paper-and-pencil questionnaire which addressed
sexual behaviors, sexual history, and communication about sexuality was
distributed to adolescent girls attending the clinic. Several important analyses
included only those who had been sexually active in the last 4 weeks (n = 452).
RESULTS: Adolescents who used OCs [odds ratio (OR) 1.7], long-acting agents
(i.e., Depo-Provera or Norplant) (OR 1.6), were less likely to have used a condom
in the last 4 weeks than teens whose only method of birth control was condoms.
Only those teens who had previously been diagnosed with a sexually transmitted
disease (STD) were more likely to have used a condom (OR .67 for not using a
condom). Overall, condom use by teens in this sample was low, with only 19%
reporting that they "always" use a condom, and 47% of the teens who had been
sexually active in the last 4 weeks reporting that they had not used a condom at
least once during that time. CONCLUSIONS: This study provides data which suggest
that adolescent girls who use hormonal contraceptives are less likely to use
condoms than other sexually active teens. Therefore, when prescribing hormonal
contraception to prevent pregnancy, clinicians must provide appropriate
counseling to mitigate against the potential to increase the risk of STDs.
PMID- 9763158
TI - The sexual practices of Asian and Pacific Islander high school students.
AB - PURPOSE: To describe the sexual behaviors, beliefs, and attitudes of Asian and
Pacific Islander California high school students and to compare them to other
racial/ethnic groups. METHODS: Data were collected from an anonymous self
administered survey of 2026 ninth to 12th graders in a Los Angeles County school
district; 186 of the respondents described themselves as Asian and Pacific
Islander. The survey was conducted in April 1992. RESULTS: A higher percentage of
Asian and Pacific Islander adolescents (73%) compared with African-American (28%,
p < .001), Latino (43%, p < .001), white (50%, p < .001), and other (48%, p <
.001) adolescents had never had vaginal intercourse. Asian and Pacific Islander
adolescents were less likely than other adolescents to report having engaged in
heterosexual genital sexual activities during the prior year, including
masturbation of or by a partner, fellatio with ejaculation, cunnilingus, and anal
intercourse. Few students in any group reported homosexual genital sexual
activities. Asians and Pacific Islanders who had had vaginal intercourse were
more likely than most other groups to have used a condom at first vaginal
intercourse, but Asians and Pacific Islanders had not used condoms more
consistently over the prior year. Asians and Pacific Islanders were more likely
to expect parental disapproval if they had vaginal intercourse and less likely to
think that their peers had had vaginal intercourse. CONCLUSIONS: Asian and
Pacific Islander high school students in one California school district appear to
be at lower sexual risk than other racial/ethnic groups. However, a large
minority are engaging in activities that can transmit disease and lead to
unwanted pregnancy. Therefore, current efforts to develop culturally sensitive
clinical and community-based approaches to sexual risk prevention should include
Asians and Pacific Islanders.
PMID- 9763159
TI - Delayed first pregnancy among African-American adolescent smokers.
AB - PURPOSE: This study aimed to compare rates of adolescent pregnancy among African
American adolescents who began smoking as adolescents with those who did not.
METHODS: Cross-sectional data on 1042 primiparous African-American women enrolled
in a randomized clinical trial of nurse home visitation were examined. The
independent variable, adolescent smoking, was defined as a report of smoking
before the age of 18 years. The outcome variable was adolescent pregnancy,
defined as first pregnancy before the age of 18 years. Logistic regression was
used to control for potential confounders. RESULTS: After adjustments for drug
use, use of contraception, frequency of coitus, and sexually transmitted
diseases, women who smoked during adolescence had a 50% lower risk of becoming
pregnant as an adolescent [odds ratio of 0.46 (95% confidence interval [CI] 0.27
0.76)]. When time to first pregnancy was examined as a continuous variable,
adolescent smoking was associated with a delay in pregnancy of 22.6 months (95%
CI 16.8-29.2). CONCLUSIONS: Teen smoking appears to be associated with a
significantly lower rate of adolescent pregnancy among African-Americans.
Although the nature of this relationship is unclear, this finding suggests the
need for linkage between smoking prevention and adolescent pregnancy prevention.
PMID- 9763160
TI - Sexual orientation, sexual behaviors, and pregnancy among American Indian
adolescents.
AB - PURPOSE: A recent study found a disproportionate number of pregnancies among Euro
American lesbian and bisexual adolescents compared to heterosexual peers.
American Indian adolescents have reported higher prevalence of
gay/lesbian/bisexual orientations than Euro-Americans; do they also report higher
prevalence of pregnancy? METHODS: The study assessed prevalence of teen pregnancy
and related factors by sexual orientation among sexually experienced, reservation
based American Indian adolescent males (n = 2056) and females (n = 1693) who
participated in a national school-based survey in 1991. Self-reported orientation
was classified as heterosexual, gay/lesbian/bisexual, and "unsure" of
orientation. RESULTS: Gay/bisexual males were more likely than other males to
report early heterosexual intercourse (<14 years), more consistent contraception,
and a higher prevalence of abuse and running away (p < 0.05 to p < 0.0001).
Likewise, lesbian/bisexual females were more likely to report early onset of
heterosexual intercourse, more frequent intercourse, and running away. Sexual or
physical abuse did not vary by orientation for females. Prevalence of pregnancy
also did not vary by orientation (males, 18.6% gay/bisexual vs. 10.4% "unsure"
vs. 11.8% heterosexual; females, 25.0% lesbian/bisexual vs. 22.1% "unsure" vs.
21.9% heterosexual). For lesbian/bisexual females, no variables were
significantly associated with pregnancy history; for "unsure" females, pregnancy
was associated with contraceptive frequency and early onset of heterosexual
activity. For heterosexual females, age, intercourse frequency, and physical
abuse were associated. For gay/bisexual males, intercourse frequency, ineffective
contraception, and physical abuse were associated with involvement in a
pregnancy; for "unsure" and heterosexual males, most items except ineffective
contraception were related to pregnancy involvement history. CONCLUSIONS:
Although prevalence of pregnancy is similar, findings show group differences in
associated risk factors by sexual orientation. Interventions to reduce pregnancy
among American Indian adolescents should include assessment of sexual orientation
and behavioral risk factors.
PMID- 9763161
TI - Biplanar chevron osteotomy.
AB - We retrospectively reviewed the results of using a biplanar chevron osteotomy
performed on patients who presented with hallux valgus deformities with an
increased distal metatarsal articular angle (DMAA). The study included 17 feet
(14 patients) of 12 women and 2 men. The average follow-up was 33 months. The
average American Orthopaedic Foot and Ankle Society Hallux Metatarsophalangeal
Interphalangeal Clinical Rating Score was 91. Ten of the 14 patients (13 of 17
feet) stated that they would choose to undergo the procedure again. The hallux
valgus angle was improved from an average of 22 degrees to 18 degrees, the
intermetatarsal angle from 11 degrees to 9 degrees, and the DMAA from 16 degrees
to 9 degrees. We have demonstrated this procedure to be useful in the treatment
of symptomatic bunion deformities with an increased DMAA.
PMID- 9763162
TI - Modified Mitchell osteotomy for hallux valgus.
AB - From 1988 to 1995, 96 patients (161 feet) underwent a modified Mitchell distal
metatarsal osteotomy performed for mild-to-moderate hallux valgus. On AP x-rays
of the standing foot, the average intermetatarsal angle was corrected from 15
degrees to 9 degrees, and the first metatarsophalangeal angles were corrected
from an average of 41 degrees to 15 degrees. Criteria for evaluation of clinical
results included relief of pain, appearance of foot, and shoe wear. After an
average follow-up of 38 months, the overall satisfaction rate was 92.5%.
Complications included 13 pin tract infections, two delayed unions, and two
correction losses. The most common late sequela was transfer metatarsalgia of the
lesser toes, which occurred in 20 feet (12.4%), leading to some dissatisfaction.
The Mitchell osteotomy can be used on cases with less than 20 degrees of
intermetatarsal angle, offering a stable construct with easy postoperative care.
PMID- 9763163
TI - Traumatic extrusion of the talus (missing talus).
AB - Complete dislocation of the talus is an extremely rare injury. We report on a
case that was treated according to a surgical technique described by Gunal et al.
According to this technique, a pseudarthrosis is created between the tibia and
the calcaneus by transposing and fixing the medial malleolus laterally and
displacing the entire foot anteriorly. The result was considered to be initially
unsatisfactory. At the 2-year follow-up examination, the outcome was considered
to be satisfactory. This was attributed to preservation of motion and stability
in the new mortise.
PMID- 9763164
TI - Metastatic prostate carcinoma to the foot with magnetic resonance imaging and
pathologic correlation.
AB - Metastases to the bones of the foot from prostate carcinomas are rare and usually
are associated with diffuse metastatic disease. The authors encountered a patient
who presented with prostate carcinoma metastases limited to the right foot.
Magnetic resonance imaging correlation in this case demonstrated normal marrow
signal in the surrounding bones of the foot and increased vascularity of the
foot.
PMID- 9763165
TI - Effects of exercise on Achilles tendon healing in a rat model.
AB - The effects of motion, or lack of it, on Achilles tendon healing are not well
defined. We have recently shown that immobilization has a detrimental effect on
tendon healing in a rat model. The aim of this experiment was to determine
whether enforced exercise had an additional beneficial effect on the mechanical
and functional recovery of divided Achilles tendons in rats. Male Sprague-Dawley
rats were randomly allocated into a nonexercise and an exercise group (N = 10 for
each group). In both groups the right Achilles tendon was surgically transected.
The left, uninjured lower limb served as an internal control. Both groups of
animals were housed under identical conditions with the exception that the
exercise group swam for 15 minutes per day. Functional performance was determined
from the measurement of hindpaw prints of walking rats preoperatively and on
alternate postoperative days. On day 15, the animals were killed and weighed, and
biomechanical evaluations were performed on both the injured and uninjured
Achilles tendon constructs. There were no differences in weight at time of death.
All animals had an initial functional deficit that returned to near-normal by day
15. There were significant differences in the morphological and the mechanical
properties of the healing Achilles tendon constructs at day 15 when comparing the
injured with the uninjured Achilles tendon constructs. Supplemental exercise,
however, had no effect on the functional or mechanical recovery of injured or
uninjured Achilles tendons in the rat model.
PMID- 9763166
TI - Use of ultrasonography versus magnetic resonance imaging for tendon abnormalities
around the ankle.
AB - A prospective study was performed on 28 patients who underwent surgery for tendon
disorders around the ankle. Preoperatively, all patients had real-time, high
resolution ultrasonography performed with a 7.5 or 10 mHz transducer. Twenty of
these patients also had a preoperative magnetic resonance imaging (MRI)
examination of the ankle. A total of 54 tendons were inspected intraoperatively,
revealing a total of 24 intrasubstance or complete tendon tears. These surgical
findings were compared with the ultrasound and MRI findings, from which the
sensitivity, specificity, and accuracy were calculated for both modalities.
Ultrasound produced results with a sensitivity measurement of 100%, specificity
of 89.9%, and accuracy of 94.4%. MRI produced results with a sensitivity
measurement of 23.4%, specificity of 100%, and accuracy of 65.75%. Ultrasound
results were more sensitive and accurate than MRI in the detection of ankle
tendon tears in our study.
PMID- 9763167
TI - Healing times of diabetic ulcers in the presence of fixed deformities of the foot
using total contact casting.
AB - In a diabetic foot, ulcers can lead directly to the loss of a limb, and they may
be life threatening if the patient is not provided effective intervention
directed at healing. This study reports on the healing times of diabetic
neuropathic plantar ulcers in the presence of fixed deformities of the foot using
the ambulatory method of total contact casting (TCC). In this study, 21 subjects
with chronic diabetes mellitus, plantar ulcers, and fixed deformities of the foot
were put in casts, and their progress was followed until the ulcers were
completely healed. Results indicated that all of the ulcers healed. The average
time to healing was 67 +/- 29 days. Ulcers located in the forefoot, midfoot, and
rearfoot healed in an average of 35 +/- 12 days, 73 +/- 28 days, and 90 +/- 12
days, respectively. The location of the ulcer and the presence and location of a
fixed deformity of the foot strongly correlated with and was predictive of
healing time using TCC. The location of the ulcers and the location of the fixed
deformities of the foot should always be considered by providers of
rehabilitation who treat diabetic neuropathic foot ulcers using TCC.
PMID- 9763168
TI - Charcot restraint orthotic walker.
AB - Five patients (three with insulin dependent diabetes mellitus (IDDM), one with
noninsulin dependent diabetes mettlitus (NIDDM), and one with hereditary
sensorimotor neuropathy (HSMN)) with stage 1 Charcot's neuroarthropathy involving
the midfoot and or subtalar and ankle joints were fitted with a Charcot restraint
orthotic walker (CROW). The rationale for this orthotic management was to
maintain a plantigrade foot for ambulation and to protect the joints and skin by
the uniform transfer or distribution of weight over the foot until the time when
the pathology reached the stage of coalescence. The patients were able to fully
bear weight and to ambulate with the CROW. All patients noted varying measures of
improvement in symptoms and function at an average 12-month follow-up. The CROW
is a useful orthosis in the armamentarium for treating neuroarthropathy of the
pedal joints.
PMID- 9763169
TI - Atypical medial dislocation of the first metatarsophalangeal joint.
AB - Medial dislocation of the great toe without fracture or sesamoid separation is an
unusual event. We are reporting such a case which occurred in a man after a motor
vehicle accident. The patient was treated with closed reduction and cast
immobilization. The patient recovered all his activities after 30 days. Three
year follow-up showed a complete recovery, clinically and radiographically, with
only slight radiographic signs of osteoarthritis, which was present also in the
contralateral foot.
PMID- 9763170
TI - Posterior tibial tendon tears in young competitive athletes: two case reports.
AB - Unlike the Achilles tendon, the posterior tibial tendon does not typically
undergo acute rupture. We report two cases of posterior tibial tendon tears
occurring in young, athletic individuals (<30 years old) that required operative
intervention before the patients could return to competitive sports. We believe
that these are the first two reports of posterior tibial tendon tears occurring
in this population without the patient having a prior history of steroid
injections in the tendon. The tears we observed and described at surgical
exploration were chronic and degenerative in nature. We also comment on our
approach to treatment of posterior tibial tendon injuries in the athletic
population.
PMID- 9763171
TI - Great toe neuroarthropathy: a report of two cases.
AB - Two cases of diabetic neuroarthropathy of the great toe are presented. The
differential diagnosis is emphasized, and the literature regarding this unusual
site for symptomatic disease is reviewed.
PMID- 9763173
TI - Replantation of the great toe: two case reports.
AB - We performed two replantations of the great toe in children less than 4 years of
age. Both cases were successful, and there was no complaint of pain or
disturbance in gait, postoperatively. Good results seemed to be based on mobility
of the metatarsophalangeal joint and on sensation in the replanted toe. In our
opinion, all traumatic amputations of the great toe in children should be
replanted, if the conditions of the foot and amputated toe allow vascular and
neural reattachment.
PMID- 9763172
TI - Delayed aseptic swelling after fixation of talar neck fracture with a
biodegradable poly-L-lactide rod: case reports.
AB - A 63-year-old woman complained of acute swelling and pain in her ankle at 15
months, after fixation of a talar neck fracture with poly-L-lactide rods.
Roentgenographic and laboratory data revealed no abnormalities, but T1-weighted
magnetic resonance imaging showed a diffuse area of low intensity in the talus.
After nonweightbearing for 1 month, local findings had disappeared and the area
of low intensity shown by magnetic resonance imaging had decreased without
surgical treatment. Although there have been some reports of aseptic swelling or
synovitis after fixation of a fracture with polyglycolide rods or screws, there
has been no report of such cases with poly-L-lactide rods or screws.
PMID- 9763174
TI - Fractures of the lateral process of the talus: two case reports and a
comprehensive literature review.
AB - Fractures of the lateral process of the talus are frequently overlooked and
should be considered in the differential diagnosis of patients with acute and
chronic ankle pain. Early diagnosis is emphasized in all series reviewed in the
literature to prevent long-term complications. Thorough radiographic evaluation
is necessary to determine the need for operative vs. nonoperative management.
Small nondisplaced fractures are treated with cast immobilization, whereas large
or displaced fractures usually require open reduction and internal fixation.
Comminution of fragments may necessitate surgical excision. To achieve the best
possible results, a timely diagnosis is required, and it is our belief that early
treatment has better overall results.
PMID- 9763175
TI - Hyperdorsiflexion sign in tears of the tendo Achillis.
PMID- 9763176
TI - Treatment of diabetic (neuropathic) foot ulcers with two-stage debridement and
closure.
PMID- 9763177
TI - Acoustic analysis of induced vocal stress by means of cognitive workload tasks.
AB - The purpose of this study was to determine the acoustic effects on voice of three
tasks of cognitive workload and their possible relationship to stress. Acoustic
analysis was used to measure stress and workload in four experimental tasks and
two experiments. In the first experiment, subjects performed cognitive workload
tasks under a stressful condition, performing the tasks as rapidly as possible
without errors and with the knowledge that any errors committed would reduce
their grade in a course. The second condition was to perform the same tasks but
without the condition of stress related to the final grade. Four testing
conditions were included. One was a baseline measure in which subjects spelled
the Spanish alphabet. The second was the reading of a tongue twister, the third
was the reading of a tongue twister with delayed auditory feedback, and the
fourth was spelling the Spanish alphabet in reverse order. In each condition the
subjects prolonged the vowel /a/ for, approximately 5 sec. All subjects performed
a test to determine their overall level of anxiety. The results suggest that in
conditions of experimentally induced stress there is an increase in the
fundamental frequency (F0) relative to baseline, an increase in jitter and
shimmer, an increase in the high-frequency harmonic energy, and a decrease in
spectral noise.
PMID- 9763178
TI - Vocal fold strain and vocal pitch in singing: radiographic observations of
singers and nonsingers.
AB - The relationship between vocal fold strain and vocal pitch in singers and
nonsingers singing a rising pitch series has been indirectly investigated by
means of lateral radiographs. Nonsingers tend to exhibit more strain than
singers. To standardize the degree of strain, an index of strain per semitone is
proposed. The semitone strain indicates the average amount of strain per 1
semitone of pitch increase or decrease. The index has been shown to be affected
by several factors: gender, singing training, singing technique, voice class,
age, and status of muscle function. Observations suggest that similar groups of
individuals occupy different positions on the stress-strain curve, indicated by
their semitone strain values.
PMID- 9763179
TI - Laryngeal airway resistance in teachers with vocal fatigue: a preliminary study.
AB - A noninvasive pressure-flow technique was used to compare laryngeal airway
resistances in nine female classroom teachers with symptoms of vocal fatigue and
seven teachers without symptoms of vocal fatigue. Data were collected two times
per day on the Monday, Wednesday, and Friday of a typical work-week. No
significant between-group differences were found, but two within-group
differences were notable. Airflow in the fatigued subjects decreased across the
sampling period (p = .0009). In the controls, air pressure increased across the
sampling period (p = .021). These findings suggest that both groups may have
reacted to vocal demands during the week by employing two different strategies to
maintain habitual laryngeal airway resistance: laryngeal adjustments alone or
laryngeal adjustments plus increased respiratory drive. The first strategy,
employed by the fatigued subjects, may have been less efficient, thereby
provoking conditions associated with their vocal fatigue.
PMID- 9763180
TI - Direct measurement of subglottic pressure and laryngeal resistance in normal
subjects and in spasmodic dysphonia.
AB - This study tested the accuracy of indirect methods of measurement of laryngeal
airway resistance in normal subjects and in spasmodic dysphonia (SD). The
indirect method assumes that subglottic air pressure remains constant during the
voiced segment of a syllable. In this study subglottic air pressure was directly
measured via puncture of the cricothyroid membrane in seven normal subjects and
seven subjects with SD. The true laryngeal airway resistance was calculated and
compared with airway resistance measured using indirect techniques based on
intraoral air pressure. In five of the seven normal subjects, subglottic air
pressure did not remain constant during the voiced segment. As a result, the
error produced using indirect method of calculating average laryngeal resistance
for the normal subjects varied from -44% to +50%. For SD subjects the error
ranged from -49% to +22%. In general, the indirect technique overestimated
laryngeal airway resistance in normal subjects and underestimated the resistance
in subjects with SD.
PMID- 9763181
TI - Laryngeal adduction in resonant voice.
AB - The primary question in this study was whether subjects with nodules and subjects
with healthy larynges would produce "resonant voice" with a similar laryngeal
configuration. A second question regarded whether the electroglottographic closed
quotient (EGG CQ) could be used to noninvasively distinguish resonant from other
voice types. Twelve adult singers and actors served as subjects, including 6
persons with healthy larynges and 6 persons with nodules. Performers were used as
an attempt to maximize token validity and stability. Subjects produced repeated
tokens of resonant, pressed, normal, and breathy voice during sustained vowels.
Laryngeal adduction was directly estimated using blinded, ordinal, visual
perceptual ratings based on videoscopic views of the larynx. EGG CQs were further
calculated based on separate trials. The perceptual ratings indicated that
subjects in both groups produced resonant voice with a barely adducted or barely
abducted laryngeal configuration that was distinct from configurations for
pressed and breathy (but not normal) voice. Previous literature suggests that
this configuration may be relevant in many cases of voice therapy (1). Average
CQs distinguished resonant from pressed voice, but inconsistently distinguished
resonant from breathy voice. Further CQs were reliably different across healthy
subjects and subjects with nodules. Thus, the utility of this measure to
noninvasively estimate resonant voice may be limited, particularly without
ongoing subject-specific calibration procedures.
PMID- 9763182
TI - Voice problems among teachers: differences by gender and teaching
characteristics.
AB - This study describes the effects of teaching activities on voice problems in male
(n = 274) and female teachers (n = 280). Over 38% of the teachers studied
complained that teaching had an adverse impact on their voice and 39% of those
had cut back teaching activities as a result. Compared to males, female teachers
more frequently reported a voice problem (38% vs. 26%, p<.05), acute (p<.05), and
chronic (p<.05) voice problems, six specific voice symptoms, and five symptoms of
physical discomfort. However, there were no gender differences in the perception
that a voice problem adversely affected their current or future teaching career.
For every type of course taught, women had a higher probability of reporting
voice problems compared to men: odds ratio (OR) = 1.7-2.1. Compared with other
courses, the teaching of physical education also was associated with an increased
risk of developing a voice problem (OR = 3.7, 95% CI: 1.4-9.4) independent of
gender, age, hours/day, or years taught. This is the first study to show that in
the same occupation, females report a higher frequency of vocal symptoms than
males even when teaching characteristics and years employment are similar.
PMID- 9763183
TI - Unilateral cricothyroid contraction and glottic configuration.
AB - It is frequently stated that unilateral cricothyroid muscle (CT) paralysis can be
diagnosed by physical examination, noting rotation of the glottis, and shortening
and vertical displacement of the ipsilateral vocal fold. These signs, however,
are inconsistently observed, and there is considerable controversy regarding the
direction of glottic rotation. To determine the effects of CT contraction on
three-dimensional glottic configuration, we performed computerized tomography on
cadaver larynges before and after simulated CT contraction. Radiopaque makers
were used to compute distances. Unilateral CT contraction equally increased the
length of both membranous vocal folds, and rotated the posterior glottis less
than 1 mm. CT contraction neither adducted the vocal processes, nor significantly
their altered vertical level. These results suggest that unilateral CT paralysis
cannot be diagnosed on the basis of any clinically apparent change in glottal
configuration.
PMID- 9763184
TI - Voice range in superior laryngeal nerve paresis and paralysis.
AB - Evaluation of Physiologic Frequency Range (PFR) and Musical Frequency Range (MRP)
of Phonation was performed on 56 adults (singers and nonsingers) presenting with
superior laryngeal nerve (SLN) paresis or paralysis confirmed by laryngeal
electromyography. The most common etiology was neuritis (69.7%), followed by
iatrogenic and unknown causes,each accounting for 10.2% of cases, and finally
trauma (8.9%). Both female and male singers with SLN paresis or paralysis had
significantly higher PFR and MPR than nonsingers. Female classical singers
presented PFR and MPR of up to 10 semitones (ST) higher than nonclassical singers
and nonsingers. The lowest PFR and musical ranges were found in patients with SLN
paresis associated with recurrent laryngeal nerve paresis or paralysis. The
authors suggest that voice range measurement is a useful parameter for analyzing
the effects of SLN paresis or paralysis on voice and that it may also assist in
measuring outcome following voice therapy.
PMID- 9763185
TI - The vocal athlete and endotracheal intubation: a management protocol.
AB - Endotracheal intubation is associated with significant laryngeal sequelae that
range in severity from mild hoarseness to life-threatening tracheal stenosis.
Although the most severe trauma appears to be related to prolonged intubation,
even short-term intubation (< 1 day) can adversely affect laryngeal and vocal
function. Concern is warranted for all intubated patients, but particularly for
the vocal athlete whose livelihood and identity depend on optimal vocal function.
It is proposed that the vocal athlete faced with endotracheal intubation risk
warrants careful multidisciplinary management. A number of intubation risk
factors have been identified in the literature; however, clinical management of
vocal athletes who undergo intubation has not been addressed. In medical settings
where adverse intubation outcomes can lead to litigation, this clinical
management protocol is expected to improve the probability of favorable voice
outcome following endotracheal intubation.
PMID- 9763186
TI - Laryngeal injuries after short- versus long-term intubation.
AB - Forty-five patients were seen over a 5-year period with laryngeal injuries
following endotracheal intubation (ETI). The mean duration of ETI was 5.6 days (2
hours to 37 days). Patients intubated for less than 24 hours were most likely to
present with a vocal fold immobility or an anterior glottic web. Long-term
intubation was associated with the development of subglottic stenoses and
granulomas. Patients with vocal fold immobility were seen more often after ETI
for surgical reasons and had a significantly higher incidence of previous
intubation and tobacco usage. Subglottic stenoses were seen in younger patients
intubated for medical reasons and associated with nasogastric tubes and longer
periods of intubation.
PMID- 9763187
TI - Voice changes in women treated for endometriosis and related conditions: the need
for comprehensive vocal assessment.
AB - Hormonal treatments which have an androgenic effect have the potential to cause
vocal changes. The changes in vocal fold structure and voice quality are
considered to be irreversible. To date, studies have documented subjective vocal
changes or documented single cases without detailed, baseline voice assessments.
The impact on laryngeal function of women taking these androgenic treatments
requires further detailed, objective assessment. The need for increased awareness
of the actions of androgenic hormones on womens' voices, and the benefits of a
thorough voice assessment are discussed.
PMID- 9763188
TI - The biomechanics of the medialization laryngoplasty (thyroplasty type 1) in an ex
vivo canine model.
AB - The biomechanics of medialization laryngoplasty are not well understood. An
excised canine larynx model was used to test the effects of various sized silicon
implants. The vocal fold length, position, and tension were measured.
Medialization laryngoplasty did not affect vocal fold length. At the mid
membranous vocal fold, larger shims resulted in greater medialization and
tension. Medialization laryngoplasty neither medialized nor stiffened the vocal
process to resist lateralizing forces. We conclude that medialization
laryngoplasty provides bulk and support for defects of the membranous region of
the vocal fold, but does not appear to close a posterior glottal gap. The
selection of a surgical procedure to treat glottal incompetence should take into
account the unique biomechanical properties of the anterior (membranous vocal
folds) and posterior (cartilaginous portion) glottis.
PMID- 9763189
TI - Laryngeal rebalancing for the treatment of arytenoid dislocation.
AB - In almost every type of functional laryngeal operation a successful result hinges
on the surgeon's ability to control the muscular and ligamentous forces that act
upon the vocal folds. Most of the time these forces are small in relation to the
manipulations and resections performed. Occasionally, the forces are significant
relative to the problem encountered, resulting in a failed surgery. Of all the
many conditions that fit in to this latter description, perhaps the best example
in arytenoid dislocation. Dislocation of the arytenoid is usually secondary to
trauma with the majority of reported cases resulting from some type of anesthetic
misadventure. Two types of dislocation have been described, anteromedial and
posterolateral, each with a different mechanism of causation. This paper concerns
itself with the more common anteromedial variety and its treatment using
botulinum toxin.
PMID- 9763190
TI - Does botulinum toxin alter laryngeal secretions and mucociliary transport?
AB - Localized botulinum toxin injection disrupts cholinergic transmission and has
potential to cause focal dysautonomia. Mucociliary transport and laryngeal
secretions are thought to be mediated in part by autonomic, cholinergic
transmission. We questioned whether patients who receive Botox injection for
adductor spasmodic dysphonia (ADSD) report postinjection symptoms possibly
related to altered mucociliary clearance or laryngeal secretions. Medical
histories, audiotaped interviews, and symptom ratings were retrospectively
examined for 29 patients with ADSD who were followed after one or more Botox
injections. Patients had received bilateral, percutaneous Botox injections of 2.5
units using an EMG-guided approach. One or more weeks after injection, four
patients reported either burning, tickling, or irritation of the larynx/throat,
excessive thick secretions, or dryness. Symptoms recurred with subsequent
injections in two patients and were not associated with swallowing difficulty.
These symptoms are consistent with, but not diagnostic of, the known effects of
botulinum toxin on cholinergic, autonomic transmission.
PMID- 9763191
TI - Towards a unified theory of immunity: dendritic cells, stress proteins and
antigen capture.
AB - In less than a decade, the archetypal view that the immune system exists
primarily to distinguish "self" from "non-self" has been replaced by the paradigm
that the immune system functions primarily to distinguish dangerous from non
dangerous antigens. This change is in part due to the recent reassertion of the
importance of so-called innate immunity, which consists of non-specific
components of the immune system such as macrophages that are active prior to
exposure to antigens (In contrast, so-called acquired immunity depends upon the
generation of B and T lymphocytes that are produced after exposure to the
antigens and are specific for the antigens). The paradigm shift is also due to
the recent proposal of the "danger model" of the immune system, which provides a
conceptual mechanism by which the immune system might distinguish dangerous from
non-dangerous antigens. The role of dendritic cells (DCs) in activating T
lymphocytes is key to both innate immunity and the danger model. The purpose of
this commentary is to add an additional piece to the emerging picture of immune
system function by suggesting that heat-shock, or stress, proteins play a central
role in the activation of T lymphocytes by DCs. The uptake of stress proteins-
whose expression is induced by monokines in the earliest phases of the innate
immune response--by DCs might constitute a "danger" signal. However, through such
a mechanism, DCs may capture antigens bound to stress proteins and improve their
ability to present the antigens to other components of the immune system, such as
cytotoxic T-cells. Invoking stress proteins to amplify the immune response in
this manner can explain how animals can mount an effective primary immune
response to an antigen despite having few T lymphocytes specific for that
antigen. Finally, the "affinity-maturation" of antibody following a primary
immune response would enable the much more efficient, specific antigen-capture by
high affinity antibodies in a secondary immune response, resulting in a rapid and
specific response or "memory" on re-exposure to the pathogen.
PMID- 9763192
TI - Phosphorylation of an envelope-associated Hsp70 homolog in amyloplasts isolated
from cultured cells of sycamore (Acer pseudoplatanus L.).
AB - The presence of Hsp70 and Hsp60 molecular chaperones in amyloplasts isolated from
cultured sycamore cells was analyzed by immunoblotting. Hsp70 homologs were
located in both amyloplast envelope and stromal fractions, but no Hsp60 homologs
were detected in any of the different suborganellar fractions. Incubation of
whole amyloplasts or their envelope fraction with Mg2+ gamma-32P-ATP resulted in
a rapid phosphorylation of the envelope-associated Hsp70 homolog, which
constitutes a major target of phosphorylation in these plastids.
PMID- 9763193
TI - Human oral mucosa studies with varying blood glucose concentration by non
invasive ATR-FT-IR-spectroscopy.
AB - During the last few years infrared spectrometry has been investigated as a non
invasive clinical tool for improved understanding of in-vivo processes. Oral
mucosa has been suggested as an especially suited subject for drug delivery and
in vivo monitoring of endogenous body metabolites due to histological and
physicochemical reasons. The attenuated total reflection (ATR) technique was used
to characterize the outmost epidermal layer of human oral mucosa by means of
Fourier-transform infrared spectroscopy. The penetration depth of the probing
radiation in the mid-infrared fingerprint region, using a ZnSe-crystal for the
horizontal ATR accessory, is in the order of a few micrometers so that microlayer
information can be obtained by such a technique. Spectra of outer human lip and
saliva components are presented for comparison. For several test persons, lip
spectra were recorded during oral glucose tolerance tests. The individually
varying blood glucose concentration was followed by means of frequent blood
testing. Variability of the outmost microlayer has been studied using factor
analysis of the ATR inner-lip spectra. There is no clear evidence that blood
glucose concentration can be followed by ATR-spectroscopy of oral mucosa. Non
invasive spectroscopic methods exploiting trace signals require special attention
paid to the variability due to person-to-person differences and changes in
physiological conditions.
PMID- 9763194
TI - Detection of DNA amplification in human renal cell carcinoma cell lines using
restriction landmark genomic scanning.
AB - Gene amplification, which has often been observed in various human cancers,
appears to be associated with the development and progression of malignant
phenotypes. However, in renal cell carcinoma (RCC), conventional analytic methods
requiring specific primers and probes have revealed infrequent amplification of
known oncogenes. We attempted to determine if gene amplification was truly
uncommon in RCC. The genomic DNAs extracted from 5 human RCC cell lines were
examined by restriction landmark genomic scanning (RLGS), a two-dimensional gel
analysis which allows evaluation of approximately 2,000 radiolabelled DNA
fragments. By this method, we detected 24 distinct spots commonly amplified in at
least 2 RCC cell lines compared to normal kidneys. Comparing the present results
with chromosomal assigned-RLGS, approximately one half of these DNA fragments
proved to be located on chromosome 2, 5 or 7. Our data suggest that amplification
of unknown genes is likely to occur in RCC cell lines.
PMID- 9763195
TI - Elevated expression of chitinase 1 and chitin synthesis in myosin II-deficient
Saccharomyces cerevisiae.
AB - To determine if the attached cells formed in Myosin II-deficient Saccharomyces
cerevisiae result from deficient chitinase 1 (CTS1) expression, the activity of
chitinase 1 was assayed. Secretion of this enzyme was not prevented by a MYO1
gene deficiency, and soluble and cell wall-associated Cts1p activity were
increased approximately 5-fold and 20-fold, respectively, in these cells. The
increase in soluble activity was correlated with an increase in enzyme levels.
Likewise, intracellular chitinase activity was increased approximately 22-fold,
and the chitin content of cell walls was elevated 2-fold. These data suggest that
the origin of myo1-associated phenotypes is not due to deficient chitinase
expression and may instead be due to a deregulation of cell wall metabolism in
these cells.
PMID- 9763196
TI - An endogenous retrovirus with nucleic acid sequences similar to those of the
multiple sclerosis associated retrovirus at the human T-cell receptor alpha,
delta gene locus.
AB - Retroviruses are suspected to be involved in the pathogenesis of autoimmune
diseases, such as multiple sclerosis (MS). Here, we describe a complete
cartography of a novel human endogenous retroviral sequence with a pol domain
which shares a high homology with the pol sequence of the multiple sclerosis
associated retrovirus (MSRV). Since this new endogenous retroviral sequence is
located in the close vicinity of the locus of the human gene coding for the T
cell receptor (TcR) alpha and delta chains on chromosome 14, it could be of
potential interest for the understanding of MS pathogenesis.
PMID- 9763197
TI - SR4987 and L1210 cell lines: two models in which cholera toxin susceptibility
does not correlate with cAMP accumulation and ganglioside content.
AB - The CT-mediated signaling mechanisms have been widely used as a tool for helping
the knowledge of the more complex mechanisms regulating cell growth and
proliferation in which gangliosides are involved as receptors and cAMP as second
messenger. In the present study we compare the susceptibility of two murine cell
lines (SR-4987 stromal cells and L1210 leukemic cells) to inhibitory effect of
cholera toxin (CT) on cell growth and correlate their sensitivity to CT with
ganglioside content and intracellular cAMP accumulation. The results indicate a
very different response of the two cell lines to CT treatment. L1210 cells (which
contain GM1a ganglioside) are sensitive to the inhibiting activity of CT (IC50 in
the clonogenic assay = 10(-9) M) but no cAMP accumulation was observed after the
treatment. SR-4987 cells (which lack GM1a) show a dramatic increase of
intracellular cAMP without any inhibition of cell growth following the CT
treatment until 10(-8) M. However, after SR4987 cells have incorporated GM1a they
became susceptible to CT (with a IC50 value = 10(-11) M). The comparison of these
results with our previous studies on WEHI-3B leukemia cells confirms the
remarkable heterogeneity of cell sensitivity to the growth inhibition by CT by
emphasizing that this inhibition is the final event of very different mechanisms
in which CT binding to a specific ganglioside seems to be necessary and
sufficient whereas cAMP accumulation may not be coupled with the
antiproliferative effect of CT.
PMID- 9763199
TI - A model to study c-myc and v-H-ras induced prostate cancer progression in the
Copenhagen rat.
AB - Normal rat prostate epithelial cells (EPYP-1) were isolated and immortalized with
the Simian Virus-40 (SV40) large T-antigen, and transfected with the v-H-ras
(EPYP-1-ras) and the c-myc oncogenes (EPYP-1-myc; EPYP-1-ras-myc) to serially
create a step-wise model of tumor development in the rat prostate. Pronounced
morphological differences were observed between EPYP-1 and the transfected
sublines. The immortal epithelial cells (EPYP-1) maintained a cuboidal shape with
orderly, contact mediated inhibition of growth. Oncogene transfected clones
displayed a spindle shaped structure with multiple overlapping pseudopodia.
Transfected cells also exhibited a greater degree of dysplasia, loss of contact
inhibition growth and the upregulation of an epithelial tumor marker, cytokeratin
18. All cells exhibited anchorage independent and androgen independent growth. In
vivo, EPYP-1 cells and EPYP-1-myc and formed slowly growing non-metastatic,
benign tumors in immune compromised mice, while EPYP-1-ras and EPYP-1-ras-myc
transfected cells produced rapidly growing, malignant tumors in similar animals.
This model augments the hypothesis that tumor initiation and progression can be
caused by as few as two discrete genetic events. In addition, the "normal" rat
prostate epithelium and transfected daughter cell lines represent a tumor model
system with distinct, well understood genetic alterations: activation of ras and
myc. This model will be a valuable addition to the current cell lines used in the
investigation of prostate cancer carcinogenesis.
PMID- 9763198
TI - Liver glycogenin activity in diabetic and adrenalectomized rats.
AB - The glycogen concentration in liver is altered in various pathophysiologic
states. In fasted rats, it is higher in diabetic, and lower in adrenalectomized
rats compared to control animals. In fed rats, it is lower in diabetic, and
little changed in adrenalectomized animals compared to controls. We were
interested in determining whether the activity of glycogenin, a self
glycosylating protein that initiates the synthesis of new glycogen molecules,
could explain these differences in liver glycogen concentration. Glycogenin
activity was measured by the incorporation of 14C-glucose from UDP-U-14C-glucose
into an acid-precipitable product before and after amylase treatment of liver
extracts. The glycogenin activity was similar in normal, diabetic and
adrenalectomized fasted animals, regardless of the hepatic glycogen
concentration. In fasted rats, glycogenin was present predominantly as the free
form of the enzyme, i.e., not attached to an amylase-digestible glycan,
presumably glycogen. In contrast, in fed rats, the majority, if not all of the
glycogenin was incorporated into a glycogen-like (proteoglycan) molecule.
Proteoglycan synthase activity, previously identified in normal fed rats, also
was present in diabetic and adrenalectomized fed rats, and the activity was
similar. Thus, the altered ability to store hepatic glycogen in diabetic fed and
fasted and adrenalectomized fasted rats cannot be explained by decreases in
glycogenin or proteoglycan synthase activities, at least as measured using the
present assays.
PMID- 9763200
TI - Platelet releasate treatment improves skin healing in diabetic rats through
endogenous growth factor secretion.
AB - Although impaired skin wound healing in diabetes is a well established
phenomenon, virtually nothing is known of its underlying mechanism. We have
demonstrated that diabetic skin exhibited a significant deficiency in total
mitogenic activity, notably a diminution in FGF1, FGF2 and TGFbeta-like
molecules. We postulated that impaired skin healing could be explained by a
decreased expression of endogenous growth factors that could be compensated by a
platelet releasate (PR) added in situ. Histological studies showed that PR
treatment improved tissue repair and restored disturbed healing steps observed in
untreated diabetic rat skin although reepithelialization was not altered. Our
data demonstrate that PR treatment induces important modulations of the quantity
and the kinetic of secretion of endogenous growth factors in the wounds. Although
exogenous factors present in PR could no longer be quantified in the wounds after
3 days, our results indicated that factors contained in PR may have: 1) a direct
and immediate effect on the growth of neodermal cells, combined to 2) a long term
stimulation of endogenous growth factor synthesis in situ during cutaneous wound
healing in diabetic rats.
PMID- 9763202
TI - The effects of ceramide and its analogues on the secretion of the mucocyst
content of Tetrahymena.
AB - Monoclonal antibody to Geodia lectin is bound by the mucocyst content of
Tetrahymena. By using this (fluorescent-labelled) antibody and confocal
microscopy, the actual state of the mucocyst (position, resting, filling or
extruding) can be studied. Treatment with C2 ceramide and non-hydroxy fatty acid
caused a rapid depletion of mucocyst material. Another ceramide analogue,
psychosine caused fusion of mucocysts. In these cases--in contrast to the
controls--the contractile vacuole was filled with mucocyst material and this was
seen in the tubules in contact with the contractile vacuoles. Hydroxy fatty acid
ceramide, sphingomyelin and sphingosine-1-phosphate were ineffective. As the
former materials influence also the cytoskeleton, while the latter do not, the
cytoskeleton is presumed to have a mediatory effect. Neither the connection of
contractile vacuoles with tubular structures nor mucocyst fusion have been
described before.
PMID- 9763201
TI - Tissue distribution and subcellular localization of a G-protein activated
phosphoinositide 3-kinase. An immunohistochemical study.
AB - We studied by light-and electron microscopic immunohistochemical techniques the
anatomical distribution and subcellular localization of a G-protein activated
phosphoinositide 3-kinase gamma (PI3Kgamma) in several tissues of rat, mouse, dog
and man. Using monospecific polyclonal antisera and monoclonal antibodies to the
enzyme protein PI3Kgamma immunoreactivity was detected in rat and mouse
neutrophils, prostate, kidney, exocrine pancreas, salivary glands (parotid gland)
as well as in dog and human exocrine pancreas and parotid gland. No
immunoreactive material was found in Langerhans islet cells and in the nervous
tissue. Fine structural analysis of PI3Kgamma immunoreactivity revealed
immunolabeling of the basolateral membrane of rat kidney tubular cells and
certain cells in the parenchyma of the glandular part of rat prostate gland. Our
morphological data suggest a possible involvement of the enzyme in cellular
transport phenomena and a regulatory influence in secretory processes.
PMID- 9763203
TI - Electrophysiological effects of felbamate.
AB - Felbamate is a broad spectrum antiepileptic drug recently introduced into
clinical practice for controlling seizures in patients affected by Lennox-Gastaut
epilepsy, complex partial seizures or otherwise intractable epilepsies. However,
the cellular mechanisms by which the drug exerts its anticonvulsant actions are
not fully understood. The aim of the present article is to outline the possible
mechanisms of action of felbamate as suggested by findings obtained with
electrophysiological approaches.
PMID- 9763204
TI - Anti-angiogenic effect of TGFbeta in aqueous humor.
AB - Neovascularization is mediated by various factors in ocular tissues. Recent
studies have emphasized the role of vascular endothelial growth factor in the
induction of angiogenesis. We have previously reported that aqueous humor (AH)
suppressed vascular endothelial cell growth and angiogenesis. We speculated that
the anti-angiogenic effect of AH is mediated by transforming growth factor beta
(TGFbeta). In order to clarify the presence of TGFbeta in bovine AH, we applied
it on the heparin-sepharose affinity column and prepared two fractions (bound and
unbound fractions). We measured TGFbeta concentration in each fraction and
examined how the anti-TGFbeta antibody decreased the inhibitory effect of AH on
human umbilical vein endothelial cell growth and on in vitro angiogenesis. We
found the presence of TGFbeta2, but not TGFbeta1, in the heparin bound fraction,
and the inhibitory effect was detected in the heparin-bound fraction. Anti
TGFbeta antibody completely and dose-dependently extinguished the inhibitory
effect of AH. We propose that the inhibitory effect of AH on endothelial cell
growth and in vitro angiogenesis are both mediated by TGFbeta2. Our results
indicate TGFbeta2 is normally present in AH and protects the eye tissue against
abnormal neovascularization.
PMID- 9763205
TI - Stereoselective metabolism of bisoprolol enantiomers in dogs and humans.
AB - To clarify the mechanism of the species difference in the metabolism of
bisoprolol enantiomers, in vitro metabolic studies were performed using dog liver
microsomes and human cytochrome P450 (CYP) isoforms. The O-deisopropylation of
bisoprolol enantiomers showed biphasic kinetics in dog liver microsomes. The
intrinsic clearance (Vmax/Km) for O-deisopropylation of R(+)-bisoprolol was
higher than S(-)-isomer in both high-affinity and low-affinity components. The
R/S ratio of the intrinsic clearance in high- and low-affinity components was
1.34 and 1.65, respectively. The inhibition studies in dog liver microsomes using
CYP isoform-selective inhibitors indicated that the O-deisopropylation of both
bisoprolol enantiomers was mediated via the CYP2D and CYP3A subfamily, and
suggested that high-affinity oxidation was dependent on CYP2D. The kinds of CYP
subfamilies in dogs, which contribute to the metabolism of bisoprolol
enantiomers, were the same as those in humans. The intrinsic clearance for O
deisopropylation of R(+)bisoprolol by human recombinant CYP2D6 was also different
from that of S(-)-enantiomers (R/S:1.50). However, unlike the dog microsomes, the
intrinsic clearance by the human recombinant CYP3A4 did not show a
stereoselective difference. Therefore, the species difference in the R/S ratio of
metabolic clearance for the oxidation of bisoprolol enantiomers (dog > human) is
mainly due to the species difference in the stereoselectivity of one of the
cytochrome P450 subfamilies (CYP3A).
PMID- 9763206
TI - Melatonin decreases mRNA for histone H4 in thymus of young rats.
AB - The antiproliferative properties of melatonin have been previously demonstrated
for several normal and tumoral tissues. In a recent report we have shown that
melatonin is able to inhibit programmed cell death in thymus both, in vivo and in
vitro. Given that other authors have related programmed cell death and cell
proliferation and that no previous reports on melatonin and cell division exist
on thymus, we decide to study the possible antiproliferative effect of melatonin
in this organ measured as the levels of mRNA for the histone H4. We found that
melatonin inhibits cell division on thymus when administered chronically both, at
high (500 microg/body weight) and low (50 microg/body weight) dose. We also found
a circadian rhythm of the mRNA for histone H4, opposed to the one previously
described for melatonin, supporting the negative regulation by this hormone of
cell division on thymus. A single dose of melatonin (50 microg/body weight) was
not able to decrease the levels of mRNA for H4 in the time-points studied but
after two hours of its administration. Finally, we report the inhibitory effect
of melatonin in the cell proliferation of Harderian gland, brain, lung and
kidney.
PMID- 9763207
TI - Multiple nitric oxide sources in neurogenic plasma extravasation in rat hindpaw
skin.
AB - The contribution of nitric oxide (NO) to capsaicin-evoked plasma extravasation
was studied in rat hindpaw skin. Two inhibitors of NO synthase were used: 7
nitroindazole, with a selectivity for nerve-derived NO, and the L-arginine
derivative, N(omega)-nitro-L-arginine (L-NOARG), which is a non-selective
inhibitor. Plasma extravasation was induced by intraplantar injection of 5
microg/50 microl capsaicin and measured by the Evans blue leakage technique. Both
acute and chronic administration of 7-nitroindazole significantly reduced
capsaicin-evoked plasma extravasation in rat hind-paw skin, whereas L-NOARG
enhanced it. This enhancement was abolished non-stereospecifically by either L-
or D-arginine. Our results suggest that NO production from different sources
yields a complex action in maintaining the endothelial integrity in neurogenic
plasma extravasation.
PMID- 9763208
TI - Diabetes-induced impairment of macrophage cytokine release in a rat model:
potential role of serum lipids.
AB - Diabetes (type I and type II) affects approximately 13 million people in the
United States. Delayed and incomplete healing of wounds can be a major problem
for diabetic patients. Macrophages are an important cell in the complex process
of wound repair representing the major source of cytokines throughout the wound
healing process. Cytokines mediate many of the cellular responses critical to
timely wound repair. It has been suggested that diabetes impairs wound healing
through disruption of local cytokine production. We previously demonstrated that
platelet-derived growth factor B chain (PDGF-B) levels are deficient at the wound
site of diabetic rats. In the present study, we measured the levels of several
marker cytokines released from cultured peritoneal macrophages of diabetic,
nondiabetic hyperlipidemic, and normal rats. The diabetic condition was
associated with a generalized reduction of macrophage cytokine release.
Nondiabetic hyperlipidemic animals demonstrated similar cytokine reduction
supporting the hypothesis that elevated serum lipids are the primary determinants
of diabetes-induced reductions in macrophage cytokine release. Thus, manipulation
of serum lipids may be a therapeutically useful modality for controlling
macrophage cytokine release in the inflammatory and/or wound environment.
PMID- 9763209
TI - Ethanol-induced activation of the hypothalamic-pituitary-adrenal axis in a mouse
model for binge drinking: role of Ro15-4513-sensitive gamma aminobutyric acid
receptors, tolerance, and relevance to humans.
AB - A mouse model for binge drinking has been developed in this laboratory, and
several aspects of this model have been characterized. Many of the
immunosuppressive effects of ethanol (EtOH) in this model seem to be mediated by
activation of the hypothalamic-pituitary-adrenal (HPA) axis and consequent
increases in the concentration of glucocorticoids, catecholamines, and perhaps
other immunosuppressive mediators. The purpose of the work described here is to
examine three important issues regarding the EtOH-induced neuroendocrine response
in this model: 1) Are Ro15-4513-sensitive gamma aminobutyric acid type A (GABA-A)
receptors involved in activation of the HPA axis by EtOH? 2) Does daily
administration of EtOH produce tolerance with regard to activation of the HPA
axis or with regard to suppression of natural killer cell activity? 3) Is the HPA
axis activated by similar blood EtOH concentrations in humans and in the mouse
model? Ro15-4513, a partial inverse agonist of GABA-A receptors, did not affect
EtOH-induced increases in blood corticosterone levels. This suggests that Ro15
4513-sensitive GABA-A receptors are not involved in EtOH-induced activation of
the HPA axis and that inhibition of corticosterone production is not the
mechanism by which Ro-15-4513 blocks EtOH-induced immunosuppression. To evaluate
tolerance, mice were given a daily dose of EtOH (6.5 g/kg by gavage) or vehicle
(water) for 10 days. Control groups received vehicle or EtOH only on the last day
of the experiment. At the optimum time after EtOH administration serum
corticosterone and splenic NK cell activity were measured. The results indicate
no significant alterations in the response to EtOH of mice exposed to EtOH for 10
days compared to those exposed only once. To compare the HPA axis response of
mice and humans, lower EtOH dosages than generally used in our model were
administered to mice, and the corticosterone response was compared to published
data for humans who had similar ranges of blood EtOH levels. The results suggest
that humans and mice exhibit activation of the HPA axis only when blood EtOH
levels exceed approximately 0.14%. Together these results further characterize a
mouse model for binge drinking that seems to provide a reasonable representation
of many aspects of binge drinking in humans.
PMID- 9763211
TI - mRNA levels of the hypoxia inducible factor (HIF-1) and DNA repair genes in
perinatal asphyxia of the rat.
AB - Hypoxia inducible factor 1 (HIF-1) is a transcription factor which is expressed,
when mammalian cells are subjected to hypoxia, activating the transcription of
genes encoding proteins thought important for maintaining oxygen hemostasis. The
aim of the study was to evaluate HIF-1 mRNA levels in a non-invasive model of
perinatal asphyxia (PA). Brain was taken for studies on HIF-1 alpha and beta 10
min following the asphyctic period. To rule out influences by the redox status we
also determined antioxidant enzyme mRNA levels for superoxide dismutase,
catalase, glutathion peroxidase and performed electron spin resonance studies. To
study the link to protein phosphorylation as previously proposed, we evaluated
mRNA levels for protein kinase C. As DNA breaks were reported to occur in PA, we
determined mRNA levels of two genes representing DNA nucleotide excision repair,
ERCC2 and ERCC3, and a DNA repair gene involved in the repair of oxidation
mediated DNA damage, XRCC1. mRNAs for HIF-1 were not detectable following 5-20
minutes of asphyxia. The antioxidant enzymes did not show any changes during the
asphyctic periods either and electron spin resonance failed to detect the
presence of the hydroxyl radical. PKC significantly decreased with the length of
the asphyctic period. ERCC2 and XRCC1 mRNAs were inducible during the acute phase
of asphyxia indicating early repair phenomena. HIF-1 may not be relevant for
periods of PA up to 20 minutes, the maximal survival time in our model. Neonatal
factors may be responsible for that phenomenon although we cannot rule out that
HIF-1 changes may occur at the protein level.
PMID- 9763210
TI - In vivo and in vitro antiinflammatory activity of saikosaponins.
AB - Buddlejasaponin I and saikosaponin 1 and 2, biologically active compounds from
Scrophularia scorodonia and Bupleurum rigidum respectively, exert potent in vivo
antiinflammatory effects on mouse ear edema induced by phorbol myristate acetate
(PMA). The effects of these compounds on swelling and other inflammatory
parameters are described. In screening for in vitro effects of saikosaponins on
cellular systems generating cyclooxygenase (COX) and lipoxygenase (LOX)
metabolites, we observed that most saikosaponins showed a significant effect. The
action is more marked on LOX metabolite LTC4. Our data support the inhibition of
arachidonic acid metabolism as one of the biochemical mechanisms that might be
the rationale for the putative antiphlogistic activity of these saikosaponins.
PMID- 9763213
TI - Peribronchial lymphocyte activation in bleomycin-induced lung injury.
AB - The role of lymphocytes in bleomycin (Bleo)-induced lung injury remains obscure.
In normal hamsters, peribronchial lymphatic tissue (PBLT) has been found to
contain a large population of T lymphocytes responsive to interleukin 2 (IL-2)
but not to IL-4. Lung injury induced by a single intratracheal instillation of
Bleo in hamsters has been ameliorated by cyclosporin A (CyA). In the present
study, using this model, PBLT-derived lymphocyte function was explored for 28
days after Bleo instillation. Increase in PBLT lymphocytes occurred at five time
points investigated, reaching highest values on day +7 (p < 0.0025). Cell
proliferation in response to concanavalin A was enhanced, while IL-2 +/- the
mitogen had no effect. In contrast to its inactivity in the normal hamster, in
the Bleo-injured animal IL-4 alone induced T cell proliferation (p = 0.0077) on
day +7. CyA therapy initially suppressed and delayed recovery of the number of
lymphocytes and their activation. The results of this study suggest the existence
of a vulnerable period in Bleo-induced lung injury and indicate that lymphocytes
participate in the pathogenesis of the insult to the tissue. The unresponsiveness
to IL-2 and the emergence of cellular response to IL-4 indicate immune deviation
in PBLT-derived T cells.
PMID- 9763212
TI - Heterologous regulation of muscarinic and beta-adrenergic receptors in rat
cardiomyocytes in culture.
AB - Previous work indicated that hyperstimulation of muscarinic receptors brings
about profound changes not only in the density of the muscarinic receptors, but
also of the beta-adrenoceptors in rat heart atria in vivo. We have now
investigated whether a similar receptor cross-regulation occurs in cardiomyocytes
in vitro. Cardiomyocytes from 3-4 day old rats were exposed to chemical agents on
days 5-6 in culture. Densities of muscarinic and beta-adrenergic receptors were
measured according to the binding of N-[3H]methylscopolamine and [ H]CGP 12177,
respectively, to cell surface membranes and cell homogenates. Exposure of cells
to the muscarinic agonist carbachol (1 mmol/l) brought about a profound decrease
in the number of muscarinic receptors. The number of beta-adrenoceptors displayed
biphasic changes, being augmented after 24 h (by 20-45% on the cell surface and
by 29% in the homogenate) and diminished after 48 h and 72 h (after 48 h,
decrease by 44-75% on the cell surface and by 36% in the homogenate). These
effects of carbachol were not prevented by dimethylaminopropyl-bis
indolylmaleimide, the inhibitor of protein kinase C. Exposure of cells to the
beta-adrenoceptor agonist isoprenaline (0.1 mmol/l) strongly diminished the
number of beta-adrenoceptors on the cell surface and in the homogenate. The
density of muscarinic receptors on the cell surface was diminished by 24-43%
after 24 h exposure to isoprenaline and unchanged after 48 h, whereas the
concentration of muscarinic receptors in the homogenate was unchanged after 24 h
and increased by 20% after 48 h. The isoprenaline-induced decrease in the density
of cell surface muscarinic receptors could not be simulated by forskolin and was
not abolished by the protein kinase A inhibitors Rp-cAMPS and HA-1004. Dibutyryl
cyclic AMP diminished the density of cell surface muscarinic receptors more than
that of the beta-adrenergic receptors. Our data reveal a novel phenomenon of a
biphasic change (an increase followed by a loss) in the density of beta
adrenoceptors during exposure of cardiocytes to carbachol. Activation of beta
adrenoceptors brings about less conspicuous changes in the density of muscarinic
receptors. The observed phenomena of receptor cross-regulation cannot be
explained by simple activations of protein kinases A and C.
PMID- 9763214
TI - A selective inhibitor of intestinal ACAT, EAB309 suppresses both intestinal and
hepatic cholesterol output and stimulates chylomicron removal.
AB - The effect of a novel inhibitor of acylcoenzyme A:cholesterol acyltransferase (EC
2.3.1.26, ACAT), EAB309 (EAB) on plasma lipid metabolism was studied in
cholesterol-fed rats. Orally administered EAB was not detected in the portal vein
or the liver but distributed exclusively in the intestine, suggesting that this
agent selectively inhibits intestinal ACAT. The rats were fed with either a
cholesterol-diet or a cholesterol-diet containing 0.005% EAB (w/w) ad. libium for
three weeks. ACAT activity in intestinal microsomes was significantly inhibited
in EAB-treated rats. Hepatic ACAT activity was also decreased in EAB-treated
rats, however, this was attenuated by the addition of excess cholesterol to the
liver microsome, indicating that substrate availability is tightly associated
with this enzyme's activity and the inhibition of hepatic ACAT by EAB is not
direct. Incorporation of [3H]-cholesterol to cholesteryl ester (CE) in mesenteric
lymph were markedly suppressed by EAB treatment. Chylomicrons (CMs) were doubly
labeled with [3H]-vitamin A and [14C]-triglyceride (TG) in EAB-treated or non
treated rats and injected into normal chow-fed rats. The CMs from EAB-treated
rats were cleared faster from the plasma and taken up more by the liver compared
with the CMs from non-treated rats. The content of CE in newly secreted VLDL was
remarkably decreased by EAB treatment without affecting TG output. These results
demonstrate that EAB, a novel inhibitor of intestinal ACAT, significantly
suppresses both intestinal and hepatic CE output and stimulates CM removal. This
suggests that the inhibition of intestinal ACAT can subsequently suppress hepatic
ACAT by decreased CE delivery from the intestine to the liver.
PMID- 9763215
TI - Enzymology of mitomycin C metabolic activation in tumour tissue: implications for
enzyme-directed bioreductive drug development.
AB - Mitomycin C (MMC) is the prototype bioreductive DNA alkylating agent. To exploit
its unique properties and maximize patient responses, different therapeutic
approaches have been investigated. Recently, the focus has concentrated on
monitoring the levels of the proteins metabolizing the drug and relating these to
activity in a regimen referred to as enzyme-directed bioreductive drug
development. To be successful, it is important to understand the enzymology of
metabolic activation not only in cell lines but also in solid tumour models. A
general mechanism of action for MMC has now emerged that is activated regardless
of the source of reducing equivalents, comprising three competing pathways that
give rise to unique reactive intermediates and different DNA adducts.
Partitioning into the pathways is dictated by chemical considerations such as pH
and drug concentration. DT-diaphorase stands out in this mechanism, since it is
much less effective at metabolizing MMC at neutral pH. At least five different
enzymes can catalyse MMC bioreduction in vitro, and as many activities may be
present in solid tumours, including a series of novel mitochondrial reductases
such as a cytochrome P450 reductase. Competition between reductases for MMC
appears to be based solely on protein levels rather than enzyme kinetics.
Consequentially, DT-diaphorase can occupy a central role in MMC metabolic
activation since it is often highly overexpressed in cancer cells. Although a
good correlation has been observed in cell lines between DT-diaphorase expression
and aerobic cytotoxicity, this does not hold consistently in vivo for any single
bioreductive enzyme, suggesting revision of the enzyme-directed hypothesis as
originally formulated.
PMID- 9763216
TI - Skeletal muscle-specific calpain, p49: structure and physiological function.
AB - Recent studies indicate that calpain, a cytosolic Ca2+-dependent protease,
constitutes a large family comprising ubiquitous, tissue-specific, and atypical
calpains. p94 is a homologue of the catalytic large subunit of calpain, expressed
predominantly in skeletal muscle. Recently, p94 has been found to interact with
connectin/titin, a muscle elastic protein, and its gene has been identified as
being responsible for limb-girdle muscular dystrophy type 2A. The loss of
function of a calpain species eventually leads to the activation of proteases
including other calpain species responsible for muscle degradation. p94 does not
form a complex with the small subunit of calpain (30K), but exists as a
homodimer. This, together with other results, led us to consider a novel
mechanism for the activation of calpain, a Ca2+-induced subunit rearrangement.
PMID- 9763217
TI - New therapeutic prospects for the glycosphingolipid lysosomal storage diseases.
AB - The glycosphingolipid (GSL) lysosomal storage diseases result from mutations in
the genes that encode the enzymes required for glycosphingolipid catabolism
within lysosomes. They are relatively rare diseases, but are frequently severe in
terms of their pathology. Many involve progressive neurodegeneration, and in the
most severe forms result in death in early infancy. The therapeutic options for
treating these diseases are limited, and for the majority of these disorders
there are currently no therapies available. To date, most research has focused on
correcting the genetic lesion by gene therapy or by augmenting the enzyme
activity deficient in these patients by introducing fully functional enzyme. This
can be achieved by bone marrow transplantation or intravenous infusion of
purified or recombinant enzyme (enzyme replacement). Gene therapy and enzyme
replacement therapy are disease specific, and pharmacological approaches for the
treatment of these disorders have not been fully explored. In this commentary,
the problems associated with disease therapy are discussed, and a pharmacological
agent (N-butyldeoxynojirimycin) is presented for the potential generic treatment
of this family of disorders. Successful prevention of glycosphingolipid storage
in a mouse model of Tay-Sachs disease suggests that this strategy merits clinical
evaluation.
PMID- 9763218
TI - Antiproliferative effect of deferiprone on the Hep G2 cell line.
AB - Iron is an essential element in cellular metabolism and the growth of all living
species, and is involved in DNA replication. The risk of hepatocellular carcinoma
development is associated with an increase in iron availability. The aim of the
present work was to investigate the effect of an oral iron chelator, deferiprone
(CP20), on HepG2 cell-line proliferation in culture. HepG2 cell cultures were
maintained in the absence of fetal calf serum (FCS) and in the presence or not
(control cultures) of CP20 at the concentrations of 50 or 100 microM;
deferoxamine (DFO) was used as an iron chelator reference. Cell proliferation was
investigated by the analysis of DNA synthesis using [3H] methyl-thymidine
incorporation and of the cell cycle by flow cytometry. Iron chelation efficiency
in the culture model was studied by analyzing the effect of CP20 on radioactive
iron uptake, intracellular ferritin level, and transferrin receptor expression.
CP20, at the concentration of 50 or 100 microM, inhibited DNA synthesis after 48
hr of incubation and induced an accumulation of the cells in the S phase of the
cell cycle. Iron chelators inhibited cellular iron uptake, decreased
intracellular ferritin level, and increased transferrin receptor protein and mRNA
levels. Our results show that CP20 as well as deferoxamine inhibit HepG2 cell
proliferation and block cell cycle in the S phase.
PMID- 9763219
TI - Down-regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA levels
and synthesis in syrian hamster C100 cells by the oxidosqualene cyclase inhibitor
[4'-(6-allyl-ethyl-amino-hexyloxy)-2'-fluoro-phenyl]-(4-bromophenyl)-me thanone
(Ro 48-8071): comparison to simvastatin.
AB - In vivo inhibition of 2,3-oxidosqualene:lanosterol cyclase (OSC, E.C. 5.4.99.7)-
the enzyme which catalyzes the cyclization of monooxidosqualene to lanosterol-
does not result in elevated 3-hydroxy-3-methylglutaryl CoA reductase (HMGR)
activity. This trait is attributed to increased levels of oxysterols, produced
upon partial inhibition of OSC, that suppress HMGR and other sterol-responsive
genes. The OSC inhibitor [4'-(6-allyl-ethyl-amino-hexyloxy)-2'-fluoro-phenyl]-(4
bromopheny l)-methanone (Ro 48-8071) was shown earlier to lower low-density
lipoprotein (LDL) cholesterol in hamsters with no increase in hepatic HMGR, in
contrast to simvastatin. To delineate the regulatory mechanism(s) by which Ro 48
8071 reduces cholesterol synthesis without raising HMGR levels, Syrian hamster
C100 cells were incubated with either Ro 48-8071 or simvastatin, and their
effects on cholesterol synthesis and LDL uptake, as well as on HMGR mRNA levels
and rates of synthesis, were determined. Using RNase protection and
radioimmunoprecipitation assays, we found that, in the absence of LDL in the
culture medium, both HMGR mRNA levels and synthesis were reduced with
concentrations of Ro 48-8071 inhibiting cholesterol synthesis by 50-75%, whereas
LDL uptake was either reduced or unchanged. In contrast, simvastatin, at
concentrations inhibiting cholesterol synthesis by the same 50-75%, increased
both HMGR mRNA levels and synthesis, as well as LDL uptake. In the presence of
LDL, HMGR mRNA levels and synthesis along with LDL uptake were little affected
after incubation with Ro 48-8071. Still, simvastatin markedly increased both HMGR
mRNA levels and synthesis in cells incubated in the presence of LDL, leaving LDL
uptake unaffected. These data suggest that inhibition of OSC by Ro 48-8071
results in an indirect down-regulation of HMGR mRNA levels and synthesis.
PMID- 9763220
TI - Modifications of oxido-reductase activities in adriamycin-resistant leukaemia
K562 cells.
AB - Adriamycin (ADR), a well-known antitumoral drug, interacts with DNA (nuclear and
mitochondrial) and cardiolipin. Moreover, ADR induces numerous mitochondrial
modifications in sensitive cells. However, no results have yet been obtained as
to the repercussions of drug effects on oxido-reductase activities in ADR
resistant cells. To analyze mitochondrial damage induced by ADR treatment, we
investigated lactate content, oxygen consumption, respiratory chain activities,
and cytochrome content in ADR-sensitive K562 cells and two ADR-resistant variants
(K562/R0.2 and K562/R0.5 cells). Biochemical investigations in ADR-resistant
cells showed several mitochondrial modifications (in comparison to the parental
cell line) according to the variant line and the physiologic state. More
particularly, in K562/R0.5 cells cytochrome c (cyt c) oxidase (COX; EC 1.9.3.1)
activity and cytochrome aa3 content dramatically decreased since cells enter into
the stationary phase. Regardless of the number of multidrug-resistant cell
subcultures in ADR-free medium, the cytochrome c oxidase activity in the
stationary phase remained unchanged, indicating an irreversible effect of the
drug. These alterations could correspond to several modifications of the nuclear
and/or mitochondrial genome(s) following acquisition of the ADR resistance
phenotype by K562 cells.
PMID- 9763221
TI - Insulin-like growth factor 1 (IGF-I) effects on sex-specific cytochrome P450
enzymes in normal and hypophysectomised male rats.
AB - The role of growth hormone (GH) in the regulation of the sex-differentiated rat
cytochrome P450 (CYP) enzymes has been extensively studied. However, little is
known about the involvement of insulin-like growth factor I (IGF-I) as a mediator
in this regulation. We wanted to study if IGF-I had effects on sex-differentiated
CYP enzymes and to compare the effects of IGF-I to the effects of GH. IGF-I, GH
or saline was administered continuously via osmotic minipumps to normal and
hypophysectomised rats for seven days. After treatment, the expression of several
sex-differentiated liver enzymes (CYP2C11, CYP2C12), the female-dominant steroid
5alpha-reductase, and the male-dominant CYP3A2 enzyme was studied at mRNA,
protein and/or functional levels. Our results demonstrate that IGF-I has marked
effects on the sex-specific expression of CYP2C11 and CYP2C12. The effects of IGF
I were similar to those of GH. In contrast, in hypophysectomised rats IGF-I gave
effects opposite to those observed after GH treatment to normal rats on the CYP3A
associated cortisol 6beta-hydroxylation. No effects of IGF-I on the steroid
5alpha-reductase activity were observed.
PMID- 9763222
TI - Purification and characterization of protease activated by sulfur mustard in
normal human epidermal keratinocytes.
AB - A membrane-bound protease induced by sulfur mustard in cultured normal human
epidermal keratinocytes (NHEK) was purified and partially characterized. Maximum
enzyme stimulation occurred at 16 hr after normal human epidermal keratinocytes
were exposed to 300 microM sulfur mustard. Purification to homogeneity of the
protease was accomplished by Triton X-100 solubilization, ultracentrifugation,
and dialysis, followed by ion-exchange chromatography through DEAE-cellulose and
finally hydrophobic column chromatography through phenyl Sepharose. Analysis of
the purified enzyme by SDS-PAGE revealed a single polypeptide at the 80 kDa
region. Further investigation of biochemical properties showed that a synthetic
serine-specific Chromozym TRY peptide and the physiological protein laminin were
good substrates for this enzyme. Moreover, this enzyme was inhibited mostly by
the serine-protease inhibitors leupeptin and di-isopropyl fluorophosphate and not
by the cysteine protease inhibitor E-64 or the metalloprotease inhibitor 1,10
phenanthroline (Component H, CH), indicating the serine protease nature of this
enzyme. This enzyme had a pH optimum in the range of 7.0 to 8.0. Amino acid
sequencing of the purified enzyme revealed that this enzyme belongs to the
endopeptidase family (serine protease), and is homologous with a mammalian-type
bacterial serine endopeptidase that can preferentially cleave K-X, including K-P.
These results suggest that serine-protease stimulation may be one of the
mechanisms of mustard-induced skin blister formation, and that some specific
serine-protease inhibitors may be useful for the treatment of this sulfur mustard
toxicity.
PMID- 9763223
TI - Differential inducibility of specific mRNA corresponding to five CYP3A isoforms
in female rat liver by RU486 and food deprivation: comparison with protein
abundance and enzymic activities.
AB - The induction of cytochrome P450 3A (CYP3A) protein and mRNA by RU486 [17beta
hydroxy-11beta-(4-dimethylaminophenyl)-17alpha-1-pro pyl-estra-4,9-dien-3-one]
treatment and food deprivation in female rat liver was studied using Western
blotting and competitive reverse transcription-polymerase chain reaction (RT
PCR). CYP3A apoprotein levels increased in response to food deprivation and to
RU486 treatment, and the combination of RU486 treatment plus food deprivation had
an apparent additive effect. Food deprivation and RU486 treatment also caused
increases in CYP3A1, CYP3A18, and CYP3A23 mRNA, and the combined effects of these
treatments on each of these mRNA forms were synergistic. CYP3A2 mRNA was not
detected in any of the treatment groups, and there was a lack of concordance
between CYP3A9 mRNA levels and the specific messages corresponding to the other
CYP3A isoforms. CYP3A9 mRNA levels were highest in food-deprived animals, whereas
RU486 inhibited CYP3A9 mRNA expression and suppressed the induction effect of
food deprivation. Food deprivation and RU486 treatment each separately caused
increased microsomal diazepam C3-hydroxylase activity, and the combined effects
of these treatments on this monooxygenase were additive. In contrast, the [N
methyl-14C]erythromycin demethylase activity of the fasted, RU486-treated group
of rats did not differ from that of the untreated group, and kinetic analyses
revealed that both groups of animals exhibited similar Km and Vmax values. These
results suggest that CYP3A9 may be primarily responsible for erythromycin N
demethylation and that the isoforms induced by the combination of fasting and
RU486 administration are CYP3A1, CYP3A23, and, to a lesser extent, CYP3A18.
PMID- 9763224
TI - Inhibition of calcineurin by the tyrphostin class of tyrosine kinase inhibitors.
AB - Because of their similarity to tyrosine, members of the tyrphostin family of
tyrosine kinase inhibitors were tested as possible inhibitors of the protein
serine/threonine phosphatase calcineurin. Calcineurin was inhibited by
tyrphostins A8 (also designated AG10), A23 (AG18), and A48 (AG112) with p
nitrophenyl phosphate as substrate. The IC50 values estimated with this substrate
were 21, 62, and 30 microM for A8, A23, and A48, respectively. Two other
tyrphostins, A46 (AG99) and A63 (AG13), did not inhibit calcineurin at
concentrations up to 200 microM. Similar inhibition was observed with tyrphostins
A8 and A23 using a phosphopeptide substrate (1.0 mM). Tyrphostin A8 showed
competitive inhibition against p-nitrophenyl phosphate as the substrate, with an
inhibition constant of 18 microM, comparable to the IC50 value. Possible chemical
and structural features influencing inhibition are discussed based on a
comparison of the structures of the tyrphostins tested.
PMID- 9763225
TI - Difference in H2O2 toxicity between intact renal tubules and cultured proximal
tubular cells.
AB - The present study was undertaken to examine the response to H2O2 and t
butylhydroperoxide (t-BHP) in various in vitro model systems of renal proximal
tubules: rabbit renal cortical slices, freshly isolated rabbit proximal tubules,
rabbit primary cultured proximal tubular cells, and opossum kidney (OK) cells. t
BHP increased lactate dehydrogenase release and lipid peroxidation in a
concentration-dependent manner over the concentration range of 0.2 to 3 mM in
cortical slices, whereas H2O2 caused a similar concentration-dependent increase
in both parameters at 5-100 mM. The sensitivity of isolated tubules to both
peroxides was similar to that of cortical slices. In primary cultured cells and
OK cells, however, the cytotoxicity of H2O2 was identical to that of t-BHP. The
cytotoxicity of t-BHP was not different among all the systems examined. The
specific activity of catalase in cortical slices was similar to that of isolated
tubules, but it was much higher than that of primary cultured cells or opossum
kidney cells. Glutathione (GSH) peroxidase activity was not different among all
the systems examined. The expression of catalase mRNA in cortical slices and
isolated tubules was higher than that in primary cultured cells, whereas those of
superoxide dismutase, glutathione peroxidase, or beta-actin were not different
among the systems. These results indicate that intact proximal tubules are more
resistant to H2O2 than are cultured proximal tubular cells, and the resistance is
due to a higher specific activity of catalase resulting from the increased
expression of its mRNA.
PMID- 9763226
TI - S9788 modulation of P-glycoprotein- and Multidrug-related protein-mediated
multidrug resistance by Servier 9788 in doxorubicin-resistant MCF7 cells.
AB - Inherent or acquired resistance to multiple natural drugs, termed multidrug
resistance (MDR), represents a major obstacle to chemotherapy. Expression of P
glycoprotein (P-gp) in MCF7mdr and MCF7R resistant cells was detected by reverse
transcription-polymerase chain reaction (RT-PCR) and Western blot analysis.
MCF7R, but not the MDR1 gene-transfected MCF7mdr cells, expressed multidrug
related protein (MRP) concomitantly. Efficacy of an MDR modulator, designated as
Servier 9788 (S9788), was estimated by doxorubicin (Dox) sensitization, Dox
incorporation, and functional rhodamine 123 assay on MCF7 cell lines. Results
showed that S9788 modulates the P-gp-associated MDR of MCF7mdr cells as well as
the Multidrug-related protein-associated MDR of MCF7R cells.
PMID- 9763227
TI - Differential sensitivities of recombinant human topoisomerase IIalpha and beta to
various classes of topoisomerase II-interacting agents.
AB - A series of topoisomerase-interacting antitumour agents were tested for their
ability to differentially inhibit the catalytic activity of either topoisomerase
(TOPO) IIalpha or beta, as judged by a DNA decatenation assay. The alpha form,
relative to the beta isoform, proved 1 to 3 times more sensitive to
nonintercalating complex-stabilizing TOPO II-interacting agents (etoposide and
derivatives) and up to 18 times more sensitive to non-complex-stabilizing
inhibitors of TOPO II ((+/-)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane [ICRF 159]
and meso-2,3-bis(3,5-dioxopiperazine-1-yl)butane [ICRF 193]). However, the beta
form of the enzyme appeared 1 to 3 times more sensitive to intercalating TOPO II
interacting agents (daunorubicin, aclarubicin and mitoxantrone). A possible
implication of these data are that tumours preferentially expressing either the
alpha or the beta isoform may be differentially responsive to various classes of
TOPO II-interacting agents.
PMID- 9763228
TI - Co-administration of polyanions with a phosphorothioate oligodeoxynucleotide (CGP
69846A): a role for the scavenger receptor in its in vivo disposition.
AB - The effects of co-administering polyanions on the pharmacokinetics of a 20-mer
phosphorothioate oligodeoxynucleotide (CGP 69846A), and the role of scavenger
receptors in its in vivo disposition, have been investigated. Following i.v.
administration, CGP 69846A was rapidly cleared from the plasma and distributed
amongst high (e.g. kidney, liver, spleen), low (e.g. skeletal muscle) and
negligible (e.g. brain) accumulating tissues. In addition it was shown that: 1)
dextran sulphate co-administration has a dose-dependent effect on the disposition
of CGP 69846A; 2) CGP 69846A undergoes renal filtration and renal accumulation
largely results from tubular reabsorption; 3) cross-inhibition studies are
consistent with CGP 69846A being recognized by scavenger receptors in vitro and
in vivo; and 4) the scavenger receptor may be an important determinant for the in
vivo disposition of CGP 69846A in mice. These studies contribute toward an
increased understanding of the mechanism underlying the pharmacokinetic behaviour
of phosphorothioate oligodeoxynucleotides.
PMID- 9763229
TI - Selective sites for polyamine binding to rabbit intestinal brush-border
membranes.
AB - The intestinal polyamine transporters have not yet been identified. Our aim was
to characterize specific polyamine binding sites in rabbit intestinal brush
border membranes (IBBM) as a starting step for identification of polyamine
transporters. This was investigated at 4 degrees and at low membrane
concentration. Saturation isotherms for [3H]putrescine (PUT) binding indicated a
single population of sites (puT) with a dissociation equilibrium constant Kd of
3.8 microM and a density of sites Bmax of 58 pmol/mg of protein. [3H]spermidine
(SPD) binding also involved only one class of sites (spD), albeit with a lower
affinity (Kd = 106 microM) and higher abundance (Bmax = 1240 pmol/mg of protein)
than puT. On the contrary, [14C]spermine (SPM) bound two classes of sites (spM1
and spM2) differing in their affinity (Kd = 2.5 and 31.4 microM) and abundance
(Bmax = 467 and 1617 pmol/mg of protein, respectively). Membrane association of
SPM at 4 degrees was much faster than that of SPD and PUT, both of which
proceeded at a similar rate. In contrast to PUT and SPD dissociation, SPM
dissociation at 23 degrees did not follow a first-order reaction. Specifically
bound [3H]PUT, unlike [3H]SPD and [14C]SPM, dissociated at 23 degrees
independently of the addition of nonradioactive polyamine. Methylglyoxal-bis
(guanylhydrazone) was an extremely potent inhibitor of PUT binding (Ki = 3.2 +/-
1.5 nM), but as with PUT and cadaverine (CAD), it did not alter [3H]SPD and
[14C]SPM binding substantially. The intestinal brush-border membrane may contain
at least three sites specific for polyamine binding and exhibiting different
ligand selectivity. Site puT might be associated with the transport system
already described for intestinal uptake of PUT.
PMID- 9763230
TI - Superoxide scavenging effect of Ginkgo biloba extract on serotonin-induced
mitogenesis.
AB - We have reported previously that serotonin (5-HT) stimulates the mitogenesis of
bovine pulmonary artery smooth muscle cells (SMCs) through active transport of 5
HT and cellular signaling that includes elevation of superoxide (O2.-) and
enhancement of protein tyrosine phosphorylation. Ginkgo biloba extract 501 (EGb
501), which has been demonstrated to act as an antioxidant, was found to block
both the elevated O2.- and the proliferative and hypertrophic influences of 5-HT
on SMCs, but not to directly inhibit the associated activation of NAD(P)H oxidase
or the stimulation of phosphorylation of GTPase-activating protein (GAP). A
similar effect of Ginkgo biloba extract 501 occurred on Chinese hamster lung
fibroblasts (CCL-39), where 5-HT receptor, as opposed to transporter, action has
been associated with mitogenesis. We conclude from these studies that Ginkgo
biloba extract 501 quenches O2.- formation by 5-HT, thereby blocking its
mitogenic effect. Stimulation of protein tyrosine phosphorylation of GAP by 5-HT
appears to precede the elevation of O2.-.
PMID- 9763231
TI - Generation of eicosanoids from 15(S)-hydroxyeicosatetraenoic acid in blood
monocytes from steroid-dependent asthmatic patients.
AB - The aim of this study was to investigate eicosanoid metabolism by human
peripheral blood monocytes (PBM) from steroid-dependent asthmatic patients as
compared to control subjects and untreated asthmatic patients. Eicosanoid
biosynthesis by PBM isolated from venous blood using Percoll gradient
centrifugation was evaluated following stimulation of 5 x 10(6) cells with
calcium ionophore A23187, with or without exogenous 15(S)-hydroxyeicosatetraenoic
acid (15(S)-HETE), and analyzed by reverse phase high performance liquid
chromatography (RP-HPLC). Without 15(S)-HETE, PBM synthesized leukotriene B4
(LTB4) only (40 +/- 12 ng and 59 +/- 11 ng for untreated and steroid-dependent
asthmatics, respectively). In the presence of 15(S)-HETE, PBM produced six-fold
smaller amounts of leukotriene B4 (P < 0.0001). They also released 5(S),15(S)
dihydroxyeicosatetraenoic acid (5(S),15(S)-diHETE) in similar amounts for all the
populations, whereas low amounts of lipoxins (LXs) were produced by PBM from
asthmatics only (2.7 +/- 0.7 ng and 4.6 +/- 2.8 ng for untreated and steroid
dependent asthmatics, respectively). Moreover, PBM were also able to release an
unknown compound containing conjugated triene chromophore. Cells from steroid
dependent asthmatic patients synthesized this unknown metabolite in higher
amounts than controls and untreated asthmatics (133 +/- 18 ng vs 52 +/- 19 ng and
68 +/- 15 ng, respectively, P < 0.02). This work shows for the first time that
human PBM are able to metabolize 15(S)-HETE and lead to lipoxins and to an
unknown metabolite, with the amounts of the latter being enhanced by long-term
corticosteroid treatment.
PMID- 9763233
TI - Seat pressure measurement technologies: considerations for their evaluation.
AB - Interface pressure measurement has generated interest in the automotive industry
as a technique which could be used in the prediction of driver discomfort for
various car seat designs, and provide designers and manufacturers with rapid
information early on in the design process. It is therefore essential that the
data obtained are of the highest quality, relevant and have some quantitative
meaning. Exploratory experimental work carried out with the commercially
available Talley Pressure Monitor is outlined. This led to a better understanding
of the strengths and weaknesses of this system and the re-design of the sensor
matrix. Such evaluation, in the context of the actual experimental environment,
is considered essential.
PMID- 9763232
TI - Regenerative response in acute renal failure due to vitamin E deficiency and
glutathione depletion in rats.
AB - In this study, we investigated some factors contributing to renal regeneration
after acute renal failure (ARF) induced by vitamin E (VE) deficiency and
glutathione (GSH) depletion. Acute renal failure was induced by feeding rats a
vitamin E-deficient diet for 6 weeks and then injecting buthionine sulfoximine
(BSO), a glutathione-depleting agent. The level of hepatocyte growth factor
(HGF), a renotropic factor for regeneration in the kidney, showed a transient
increase at 5 hr after the BSO treatment. Subsequently, renal ornithine
decarboxylase (ODC) activity, a marker of G1 phase, and labeling index (LI) of
proliferating cell nuclear antigen (PCNA), a marker of DNA synthesis (S phase),
reached peaks at 10 and 53 hr after the injection, respectively. Thus, it appears
that the increase in ornithine decarboxylase activity and subsequent elevation in
proliferating cell nuclear antigen labeling index following the increase in the
hepatocyte growth factor level in the kidneys are closely related to the renal
regenerative response after acute renal failure.
PMID- 9763234
TI - Guidelines for force-travel combinations of push button switches for older
populations.
AB - Current demographic trends indicating that older persons will comprise an
increasingly larger proportion of our population points to the need for paying
closer attention to age-related disabilities in designing products and
environments capable of accommodating this population. This study addresses the
development of design guidelines for push-button switches associated with a
variety of consumer products commonly used by older persons. Three groups, each
consisting of 12 male and female subjects, participated in the study, with all
subjects over the age of 50 and the average age being 70 years. The groups were
categorized on the basis of whether subjects were able-bodied, had arthritis
affecting their hands or fingers, or had hand tremor; these categories were
validated through the use of functional assessment tools. A scheme was developed
to categorize commercially available switches based on force-travel combinations,
and an experiment was conducted to assess the subject's ability to momentarily
and continuously operate the switches, as well as to derive the subjective
preferences for these switches. Based on observations from behavioral strategies,
and graphical and statistical analysis of preferences, a set of design guidelines
was proposed to enable consumer product designers and manufacturers to better
accommodate the needs of both able-bodied and functionally impaired older adults.
PMID- 9763235
TI - Connotation of hazard for signal words and their associated panels.
AB - The present study examined the ability of signal words (e.g. DANGER) and their
associated panels to convey hazard-level information, both individually and
redundantly. Subjects constructed signs on a computer for 30 different scenarios.
The use of signal words and panels was observed as a function of the level of
hazard associated with the scenario. The results show that (a) the connoted level
of hazard for signal words is not perceived as most standards suggest, (b)
certain panel components (e.g. colour and symbols) are most critical in conveying
hazard-level information, (c) no current set of standards or recommendations
specifies panel formats which use these panel components optimally, and (d) the
use of signal word panels was not necessarily based on the choice of signal word
or on the level of hazard for the particular scenario. The results suggest the
need for a re-evaluation of current signal word hierarchies.
PMID- 9763236
TI - Torque resistance of the passive tissues of the trunk at axial rotation.
AB - Sitting in a twisted working posture is common when driving an agricultural
tractor in the field. To be able to twist backwards, the driver has to overcome
the torque from the passive tissues (passive resistance). The purpose of this
investigation was to determine the relationship between passive resistance at
axial rotation and twisting angle of the trunk when a person is seated. Ten
healthy tractor drivers and 10 healthy office workers were passively twisted
about the cranio-sacral axis with simultaneous measurements of the torque needed
to twist them and the twisting angle. Surface electromyogram was used to control
the relaxation of the muscles of the subjects. An exponential function was fitted
to the data, which shows that passive resistance increases progressively with
twisting angle. No significant differences in trunk passive resistance due to the
subject's occupation, direction of twist or their interactions could be found.
The fitted function is useful when assessing the load in the trunk in tractor
driving, but also for other occupational activities where the trunk is twisted.
PMID- 9763237
TI - Musculoskeletal disorders among dentists and variation in dental work.
AB - The purpose was to assess risk factors in dentistry which may contribute to
musculoskeletal disorders. A questionnaire was used to identify common work
tasks, and to estimate one year prevalence for troubles (65% for the
neck/shoulder, 59% for the low back). In a field study working postures and
electromyography (shoulder/neck) were registered during the three most common
work tasks. Prolonged neck flexion and upper arm abduction were found, as well as
high static muscle activity levels (splenius and trapezius muscles). No
differences between work tasks were found regarding postures, frequencies of
movements or muscle activity. Alterations between the three work tasks do not
produce sufficient variation to reduce musculoskeletal load on the neck and
shoulders.
PMID- 9763238
TI - The role of 'know-how' in maintenance activities and reliability in a high-risk
process control plant.
AB - Using observation of a maintenance operator's activity and 'the history' that it
produced as a basis, we will discuss the role of 'know-how' in maintenance
activities, and particularly the problems raised by putting this knowledge into
words. Second, we will underline the contribution of this know-how to the
operational reliability of the facilities and we will investigate its being taken
into account in work instructions. With such issues as a basis, we will conclude
with the need for ergonomists to develop modes of interviewing to help people to
put know-how into words, so that it is recognized and considered in maintenance
activity organization.
PMID- 9763239
TI - Human factors in technology replacement: a case study in interface design for a
public transport monitoring system.
AB - This paper describes ergonomic issues raised during a project to provide a
replacement real-time bus route control system to a large public transport
company. Task and system analyses highlighted several deficiencies in the
original system architecture, the human-machine interfaces and the general
approach to system management. The eventual live prototype replaced the existing
original system for a trial evaluation period of several weeks. During this
period a number of studies was conducted with the system users in order to
measure any improvements the new system, with its ergonomic features, produced
over the old. Importantly, the results confirmed that (a) general responsiveness
and service quality were improved, and (b) users were more comfortable with the
new design. We conclude with a number of caveats which we believe will be useful
to any group addressing technology impact in a large organisation.
PMID- 9763240
TI - An ergonomic approach to public squatting-type toilet design.
AB - This paper reports a case study on public squatting-type toilet design, which was
undertaken with a special emphasis on ergonomic considerations. A field survey on
the use of public toilets in Taipei reveals that almost half of the subjects take
a non-sitting posture while using the sitting-type public toilets and 86% of the
subjects agreed that the squatting-type public toilets better satisfy sanitary
requirements. An experiment was conducted to determine relevant anthropometric
data for a redesign of squatting-type toilets. One of the variables studied was
the effect of the footstep slope on squatting comfort. A total of 80 subjects as
tested on four footstep slopes: 0 degrees, 15 degrees, 30 degrees and 45 degrees.
Their heart rates were measured before and after the test, and their subjective
evaluations of squatting comfort were also recorded. The 15 degrees slope was
found to be preferred. These findings were then used in design development where
mock-ups were presented to subjects for evaluation, then modifications were made
and further tests conducted for verification. The result shows that the ergonomic
approach is feasible recommended to be adopted in the process of product design
of such facilities.
PMID- 9763241
TI - Developmental toxicity of metal chelating agents.
AB - Chelation therapy is the basis for the treatment of metal poisoning. A number of
chelating agents have been widely used since the 1950s. Since these agents can be
potentially given to a metal-intoxicated pregnant woman, their intrinsic
developmental toxicities are a matter of concern. While the embryo/fetal toxic
effects of some chelators have been reported to occur at doses higher than those
currently given in the medical treatment of metal poisoning, according to
experimental data the potential use of other metal antidotes is controversial. In
those cases, the benefits and risks of usage should be carefully weighed. The
developmental toxicity of known chelators of clinical interest is presented here.
Chelating agents were divided according to the following structurally related
categories: polyaminocarboxylic acids, chelators with vicinal -SH groups, beta
mercapto-alpha-aminoacids, hydroxamic acids, ortho-hydroxycarboxylic acids, and
miscellaneous agents. Since it has been demonstrated that the teratogenic
potential of most chelators is, at least in part, due to induced trace element
deficiencies, the advisability of mineral supplements during chelation treatment
is also discussed.
PMID- 9763242
TI - Is benzodiazepine use during pregnancy really teratogenic?
AB - Benzodiazepines (BDs) have a widespread use among people suffering from anxiety.
These drugs easily cross the placenta and may affect the developing embryo and
fetus. The literature is divided as to whether BD may cause an increase in
spontaneous abortions or congenital anomalies. From the years 1988 to 1996, 756
women called the Israeli TIS concerning exposures to BD prior to or during
pregnancy. Of 599 women who called us during pregnancy, we have follow-up
information on 460 pregnancies (76.6%). The incidence of congenital anomalies
(3.1%) was not different from that found in 424 control pregnancies (2.6%). There
was a significantly higher incidence of induced abortions (14.1% vs. 4.7%, P =
0.00) and of spontaneous abortions (8.7% vs. 5.2%, P = 0.01). From an examination
of our results, it does not appear that BD during pregnancy caused an increase in
the incidence of birth defects. There was no specific defect in the offspring.
The increase in the rate of induced abortions is probably related to the
counseling of the callers, and the increase in spontaneous abortions seems to be
a result of the lower gestational age at the time of counseling in the women
exposed to BD. It is unknown whether BD could be responsible for developmental or
behavioral problems, which are observed only at a later stage.
PMID- 9763243
TI - Transplacental pharmacokinetics of cocaine and benzoylecgonine in plasma and hair
of rhesus monkeys.
AB - There is large variability in the rate and extent of fetal damage from cocaine in
humans; however, the sources of such variability are not presently known. In
order to study the relationship between maternal cocaine pharmacokinetics at the
end of pregnancy and maternal or infant cocaine and benzoylecgonine hair
concentrations at birth, ten rhesus monkeys were administered cocaine
intramuscularly throughout pregnancy. Cocaine and benzoylecgonine hair
concentrations were determined at birth and correlated with maternal
pharmacokinetics during pregnancy. There were no correlations between either
maternal cocaine Cmax or AUC0-infinity and maternal and infant hair cocaine or
benzoylecgonine concentrations. There were no significant correlations between
maternal hair benzoylecgonine concentrations and either maternal benzoylecgonine
AUC0-120 (r = 0.60; P = 0.07) or benzoylecgonine Cmax (r = 0.60; P = 0.07). No
correlations existed between infant hair benzoylecgonine concentrations and
either maternal benzoylecgonine AUC0-120 (r = 0.30; P = 0.40) or benzoylecgonine
Cmax (r = 0.30; P = 0.40). Also, no correlation was found between maternal
cocaine dose and maternal or infant cocaine and benzoylecgonine hair
concentrations. In comparison to toxicants such as nicotine and carbon monoxide
for which there is a good correlation between maternal systemic exposure and
neonatal concentrations, the lack of a similar relationship for cocaine is
consistent with the role of the placenta in contributing to the variability in
the amounts of cocaine reaching the fetus and hence, potentially to the risk of
adverse fetal outcome.
PMID- 9763245
TI - The effect of zinc supplementation on the effects of lead on the rat testis.
AB - With increasing concerns about environmental pollution, the interaction of
micronutrients with toxic metals is of great interest. The present study was
designed to investigate testicular effects of lead following concomitant
administration of zinc. Lead was administered orally as lead acetate (50 mg/kg
b.w.) daily for 3 months to male Portan rats with or without zinc (1 mg/kg b.w.
as zinc sulphate). The control group was given the same volume of distilled
water. Endpoints included lead concentration in various body organs as well as in
the reproductive system, including testicular subfractions; the testicular
enzymes superoxide dismutase (SOD) and catalase; the marker enzyme delta
aminolevulinic acid dehydratase (delta-ALAD); and testicular histoarchitecture.
The concentrations of lead in bone, kidney, prostate, testis, liver, epididymis,
spleen, seminal vesicles, and blood were significantly higher in lead-treated
rats. Lead deposition was reduced in animals that received supplemental zinc.
There was a 30% reduction in lead deposition in the testis when zinc was
coadministered. At the subcellular level, there was differential accumulation of
lead; the nucleus preferentially took up the metal after lead treatment alone,
while zinc coadministration shifted lead accumulation to the mitochondria. A
significant decrease in delta-ALAD and in SOD activity was seen in the testis
with lead treatment. Coadministration of zinc prevented these decreases, at least
partially. Zinc coadministration did not prevent the inhibition of catalase
observed with lead treatment. Histologically, the alterations in the testis with
lead treatment alone were more pronounced compared to animals in which zinc was
supplemented. Improvement in the inhibition of delta-ALAD and in the ubiquitous
cellular enzyme SOD suggests less testicular tissue damage due to detoxification
of free radicals. In conclusion, zinc supplementation ameliorates lead-induced
testicular damage both at the cellular and subcellular level. The protective
effect may be due to differential distribution of lead, either because of
competition between lead and zinc or displacement of lead by zinc.
PMID- 9763244
TI - Dysmorphogenic effects of a specific protein kinase C inhibitor during
neurulation.
AB - Protein kinase C (PKC) plays a key role in signal transduction and is an
important mediator of events throughout development. However, no information
exists regarding the effect of a specific PKC inhibitor on mammalian
embryogenesis during neurulation. This investigation was undertaken to examine
the effects of a specific inhibitor of PKC, as well as inhibitors of other
important kinases, on cultured mouse embryos. CD-1 mouse embryos (3 to 6 somite
stage) were exposed to bisindolylmaleimide I (a specific PKC inhibitor) as well
as specific inhibitors of PKA, PKG, and MAP kinase kinase for 24 h. The PKC
inhibitor was a potent embryotoxicant and elicited malformations at
concentrations as low as 0.01 microM. Inhibitors of other kinases also produced
malformations but at much higher concentrations than those required to produce
similar defects with the PKC inhibitor. These data suggest that PKC plays an
important role in mammalian neurulation. Further research is required to clarify
the mechanism by which PKC inhibition at this developmental stage produces
malformations and the potential effects of environmental toxicants with PKC
inhibitory properties on this signal transduction pathway.
PMID- 9763246
TI - Behavior and reproductive function of rat male offspring treated prenatally with
5-bromo-2'-deoxyuridine.
AB - 5-Bromo-2'-deoxyuridine (BrdU) was administered intraperitoneally to Sprague
Dawley rats at doses of 50 mg/kg/d on Days 9 through 15 and at 100 mg/kg/d on
Days 16 through 20 of gestation. Dams were allowed to deliver naturally. Male
offspring were subjected to a variety of pre- and postweaning behavioral tests:
surface righting, negative geotaxis, open field test, Biel maze test, wheel cage
test, and shuttlebox avoidance test. After puberty, masculine sexual behavior was
observed. Male offspring of dams treated with BrdU on Days 9 through 15 of
gestation showed an accelerated negative geotaxis reflex and increased ambulation
and rearing in open field, while those of dams treated on Days 16 through 20 of
gestation showed normal activity. Offspring of dams treated on Days 9 through 15
of gestation showed a higher activity level in the wheel cage than offspring of
dams treated on Days 16 through 20 of gestation. In the Biel maze, offspring of
dams treated on Days 9 through 15 of gestation showed impaired learning and
memory. In the shuttlebox avoidance response, offspring of dams treated on Days 9
through 15 of gestation moved significantly more than offspring of dams treated
on Days 16 through 20 of gestation. Masculine sexual behavior was markedly
reduced in male offspring of dams treated on Days 9 through 15 of gestation.
However, no significant differences between groups in blood pressure nor heart
rate were noted. We conclude that male offspring of dams treated with BrdU on
Days 9 through 15 of gestation are hyperactive without hypertension and that
these offspring show an impairment of masculine sexual behavior, i.e.,
hyposexuality.
PMID- 9763247
TI - Influence of organochlorine pesticides on transmembrane potential, oxidative
activity, and ATP-induced calcium release in cultured bovine oviductal cells.
AB - The present study investigated the effects of the pesticides DDT, MXC, and
gammaHCH on transmembrane potential, oxidative activity, cytotoxicity and ATP
induced intracellular Ca2+ release in cultured bovine oviductal cells.
Transmembrane potential, oxidative activity, and cytotoxicity were assessed using
the fluorescent dyes bis-oxonol, dihydrorhodamine 123, and propidium iodide (PI),
respectively, and measured spectrofluorometrically in a microplate reader. The
cultured cells were loaded with Ca2+-sensitive fluorochrome fura-2-AM, and
cytosolic free calcium ([Ca2+]i) was monitored by a microscope image analysis
system. A dose-dependent increase in depolarization and changes of oxidative
activity were observed over a concentration range of 8 to 128 microM DDT and MXC
compared to nonexposed controls. At a concentration of 16 microM DDT or MXC, the
oxidative activity and depolarization of cells were significantly enhanced
compared to controls, but most of the cells were intact as indicated by the fact
that PI-staining was not significantly increased. Trypan-blue staining indicated
that the viability of oviductal cells decreased significantly when exposed to
concentrations of 64 and 128 microM DDT or MXC. ATP-mediated enhancement of
[Ca2+]i in cells was almost completely inhibited after incubation with 128 microM
DDT for 3 h at 37 degrees C. This response was reduced to approximately 50% after
incubation of the cells with MXC at 128 microM; lindane did not significantly
interfere with the above physiologic parameters.
PMID- 9763248
TI - Influence of organochlorine pesticides on maturation and postfertilization
development of bovine oocytes in vitro.
AB - The aim of this study was to perform a dose-response test to determine whether
bovine oocytes exposed to dichlorodiphenyltrichloroethane (DDT),
hexachlorocyclohexane (gammaHCH), or methoxychlor (MXC) in vitro would exhibit
changes in maturation rates, cleavage rates at Day 2, or blastocyst rates at Day
7 to 8 after fertilization in vitro (IVF). All three pesticides affected
maturation and degeneration rates in a dose-dependent manner, but to different
extents. Higher concentrations of pesticides were associated with higher rates of
chromatin degeneration. Because the maturation of bovine oocytes was depressed in
a dose-dependent manner, the fertilizability and further embryonic development of
in vitro matured oocytes was studied at the lowest previously tested
concentration (7.25 microg/mL) only. No significant difference in fertilization
rates was seen between unexposed control and treated groups. The cleavage rates
did not differ among groups 48 h after IVF. The number of morulae and blastocysts
on Day 7 to 8 after IVF, which is commonly used as a parameter for normal
development, was significantly different between control and DDT- and gammaHCH
treated groups, but not between the control and MXC groups. The pesticides did
not differ significantly among themselves. These results show that the tested
pesticides decrease the rate of normal oocyte maturation in vitro in a dose
dependent manner. The effect of the lowest concentration of pesticides is seen
only after Day 7 of embryo development.
PMID- 9763249
TI - Arterial reconstruction in the ischemic hand and wrist: effects on microvascular
physiology and health-related quality of life.
AB - Patients were evaluated before and after arterial reconstruction surgery (1) to
define the physiology of the digital microcirculation in chronic subcritical
ischemia, (2) to demonstrate the short-term effects of successful arterial
reconstruction on microvascular flow, and (3) to document the effects of surgery
on symptoms, function, and health-related quality of life. Arterial insufficiency
was the result of a proximal reconstructible occlusive lesion, 1 or more distal
unreconstructible occlusions, and secondary reactive vasospasm. Microvascular
physiology was evaluated by monitoring digital temperatures, microvascular
perfusion (laser Doppler fluxmetry) and perfusion patterns (laser Doppler
perfusion patterns (laser Doppler perfusion imaging). Following successful
vascular reconstruction, digital temperatures and microvascular perfusion
improved significantly, approaching control levels. Although cold sensitivity was
unchanged, symptoms decreased and upper extremity function and health-related
quality of life improved after successful proximal reconstruction in patients
with 2-level arterial occlusion.
PMID- 9763250
TI - Major replantation versus revision amputation and prosthetic fitting in the upper
extremity: a late functional outcomes study.
AB - The functional outcomes of amputated arms that were either replanted or had a
prosthesis were compared. In addition, factors that influenced the functional
outcome of replants were evaluated. The Carroll test was used to evaluate
functional capacity of 22 successful upper extremity replantations at or proximal
to the wrist as well as 22 amputees (at similar levels) fitted with a variety of
prosthetic devices. The outcome was excellent or good in 8 (36%) replanted limbs.
This proportion was statistically higher than those grades in the prosthetic
group. When the groups were more closely matched (adults with below elbow
injuries), the replantation group had 6 (50%) good or excellent outcomes and the
prosthetic group had none. An analysis of covariance of the replantations
demonstrated a statistical association between a better outcome in younger
patients with more distal injuries. This study indicates that replantation
produces superior functional results compared with amputation and a prosthesis.
PMID- 9763252
TI - Vascular anatomy of the ulna.
AB - The vascular anatomy of the ulna was studied. Ten fresh-frozen upper extremity
specimens were injected with India ink and latex solution. The extraosseous
anatomy was dissected. The intraosseous anatomy was evaluated after treatment
with the modified Spalteholtz technique. The proximal periarticular portion of
the ulna was supplied by numerous, very small periarticular branches running in
the capsule. A major intramedullary nutrient vessel arose from the ulnar artery
or ulnar recurrent artery in all specimens and entered at the base of the
coronoid. The ulnar artery gave off a common interosseous artery that branches
into posterior and anterior interosseous vessels that course distally on the
interosseous membrane. The interosseous vessels were critical for they supply the
only observed vascular branches to the ulna diaphysis. The anterior interosseous
vessel supplied on average 7 branches (range, 3-11 branches) to the ulna
diaphysis spaced at generally regular 2-cm intervals, with the number of branches
decreasing in the distal third. The posterior interosseous artery supplied an
average of 11 branches (range, 9-14 branches) to the ulna diaphysis spaced at 1
cm intervals. The distal ulna metaphysis was supplied by terminal branches of the
anterior interosseous artery. The ulnar head was supplied by small branches off
the ulnar artery proper. In summary, the blood supply to the ulna diaphysis was
dependent on segmental vessels provided by the anterior and posterior
interosseous vessels. No dominant intramedullary vessel was observed in the
diaphysis. The interosseous vessels should be protected when treating a ulna
fracture or a nonunion, or when performing an osteotomy.
PMID- 9763251
TI - The effect of transdermal nicotine on digital perfusion in reformed habitual
smokers.
AB - The effects of transdermal nicotine-assisted smoking cessation on digital
perfusion and health-related quality of life were assessed in 10 chronic smokers.
Components of digital blood flow were evaluated by digital temperature and laser
Doppler fluxmetry before, during, and after a standardized cold challenge.
Nutritional flow was measured by vital capillaroscopy; a quantitative perfusion
profile was obtained by laser Doppler perfusion imaging. A battery of validated
measures were used to evaluate health-related quality of life. The microvascular
response of smokers was evaluated before smoking cessation and at 2 and 7 days
after smoking cessation and was compared with the response of nonsmoking
controls. Results demonstrated that a (1) cutaneous microvascular perfusion was
lower in smokers than nonsmokers, (2) the acute administration of transdermal
nicotine did not decrease cutaneous perfusion, (3) smoking cessation and
transdermal nicotine normalized digital microvascular perfusion by 7 days, and
(4) transdermal nicotine and smoking cessation did not negatively impact health
related quality of life.
PMID- 9763253
TI - The histologic anatomy of the volar plate.
AB - The volar plate (VP) is critical to the stability of the proximal interphalangeal
joint. This study clarifies the macro- and micro-architectural structure of the
VP and correlates these findings with its functional properties. Microscopic
evaluation of cadaver specimens revealed a trilaminar structure of the VP with
differential orientation and organization of collagen fibers in the volar,
central core, and dorsal check rein sections of the plate. This description
differs from the existing literature and adds to the understanding of the
functional properties of the VP. The most important finding is a dense "basket
weave" of collagen fibers oriented in 2 perpendicular planes within the central
core of the VP. This orientation may contribute primarily to the resistance of
the VP to both longitudinal and torsional stress. This study adds to the
understanding of the histologic basis for the function of the VP and the
mechanisms involved in its injury.
PMID- 9763254
TI - Palmar fracture dislocation of the proximal interphalangeal joint.
AB - Palmar fracture dislocation of the proximal interphalangeal joint is uncommon.
Thirteen patients treated for this injury were retrospectively reviewed. There
were 9 acute injuries. Seven were treated by closed reduction and percutaneous
pin fixation and 2 were treated by open reduction and internal fixation. The 4
chronic injuries (more than 1 month after injury) were treated with open
reduction and soft tissue reconstruction. The length of follow-up averaged 55
months. Eight patients were free from pain. Postoperative proximal
interphalangeal motion averaged 91 for the acute injuries and 70 degrees for the
chronic injuries. Follow-up radiographic findings were notable for an increased
height of the middle phalangeal base in 6 patients, articular irregularity in 4,
and residual subluxation in 2; however, these changes did not correlate with the
clinical results. Complications included loss of reduction in 1 patient,
progressive swan neck deformity in 1, and development of an average 25 degrees
extension lag of the distal interphalangeal joint in 5.
PMID- 9763255
TI - In situ osteotomy for extra-articular malunion of the proximal phalanx.
AB - Eleven patients had correction of extra-articular malunions of the proximal
phalanx by in situ osteotomy stabilized with a dorsal plate, which healed within
7 weeks. The patients' average age was 27 years; 8 of the patients were male.
After an average follow-up period of 35 months (range, 25-54 months), all the
patients had correction of the overlapping or scissoring of the digits during
flexion. The rotation deformity improved from 17 degrees to 2 degrees and the
angular deformity present in 6 patients improved from 14 degrees to 0 degrees.
None of the patients lost motion. On average, the patients improved from 85
degrees to 100 degrees flexion for the proximal interphalangeal joint and from 45
degrees to 55 degrees for the distal interphalangeal joint.
PMID- 9763256
TI - Complications and range of motion following plate fixation of metacarpal and
phalangeal fractures.
AB - Eighty-two patients with 105 metacarpal and/or phalangeal fractures stabilized
with plates were retrospectively reviewed to assess complications and outcomes.
Despite stable fixation and early mobilization, major complications were
encountered in 36% of fractures, especially with phalangeal and open fractures.
Complications included stiffness, nonunion, plate prominence, infection, and
tendon rupture. Forty-eight of 63 (76%) metacarpal fractures and 44 of 66 (67%)
closed fractures had a final range of motion greater than 220 degrees; however,
only 4 of 37 (11%) phalangeal fractures and 8 of 34 (24%) open fractures achieved
this outcome. Despite technical advances in plate design and instrumentation,
including lower-profile titanium plates, complications occur commonly with
metacarpal and phalangeal fractures, leading to a high incidence of
unsatisfactory results. We do not condemn plate fixation, and attribute many of
our unsatisfactory results to the frequent use of plates in open and phalangeal
fractures.
PMID- 9763257
TI - The Stener lesion revisited: a case report.
AB - Proximal displacement of a ruptured ulnar collateral ligament of the
metacarpophalangeal joint of a thumb (Stener lesion) can result in chronic
instability if left untreated. Rupture without displacement generally leads to
complete recovery. An associated fracture can give information about the position
of the ruptured ligament. However, 2 cases are presented demonstrating that
displacement of the ligament can occur in the absence of displacement of the bony
fragment. This suggests that physical examination is required to determine
stability with injuries to the ulnar structures of the thumb metacarpophalangeal
joint.
PMID- 9763258
TI - Isolated closed rupture of the bony insertion of the flexor digitorum
superficialis tendon: an unusual case.
AB - We describe a case of isolated rupture of the flexor digitorum superficialis
tendon due to middle phalangeal cortical bone avulsion with a 4-month delay in
treatment. X-ray examination revealed an area of calcification in the flexor
tendon sheath proximal to the proximal interphalangeal joint. Excision of the
bone fragment and surrounding scar tissue corrected nearly all the 60 degrees
extension lag at the proximal interphalangeal joint, which was the most notable
functional loss.
PMID- 9763259
TI - Limited surgical treatment of de Quervain's disease: decompression of only the
extensor pollicis brevis subcompartment.
AB - A septum between the abductor pollicis longus tendon and the extensor pollicis
brevis (EPB) tendon in the first extensor compartment is frequently encountered
during surgical treatment of de Quervain's disease. It was hypothesized that de
Quervain's disease was secondary to EPB entrapment and the decision was made to
decompress only the EPB subcompartment. Twenty-two patients were treated with
this method. Sixteen patients had a septum in the first extensor compartment and
6 patients had a single canal. After surgery, all patients had complete relief of
pain and tenderness over the first extensor compartment. The results of
Finkelstein's test were negative in all cases. We conclude that de Quervain's
disease is secondary to EPB entrapment. In those cases with a septum, it is
sufficient to decompress only the EPB subcompartment.
PMID- 9763260
TI - Motor collateral sprouting through an end-to-side nerve repair.
AB - The outcome of end-to-side repair of peripheral nerves was investigated. The
sciatic nerve in 10 male Sprague-Dawley rats was dissected to its tibioperoneal
junction. The nerve to the medial gastrocnemius muscle, branching from the tibial
nerve, was ligated at its origin and divided. Its distal end was sutured to an
epineurial window on the side of the intact tibial nerve 1 cm distally. At 12
weeks, physiologic evaluation of the medial gastrocnemius muscle and analyses of
histologic preparations of nerve and muscle were performed. The results showed
that reinnervation successfully occurred in 8 rat media gastrocnemii. The mean
weight of the reinnervated medial gastrocnemius was 73% of the contralateral
normal muscle, the mean muscle fiber cross-sectional area of the reinnervated
muscle was 72%, and the force of contraction was 60%. Analyses of histologic
preparations revealed evidence of myelinated axons in the medial gastrocnemius
nerve and no evidence of damage to axons of the donor tibial nerve.
PMID- 9763261
TI - The anatomy of the recurrent branch of the median nerve.
AB - One hundred one fresh-frozen cadavers were dissected under loupe magnification to
spatially define the origin of the recurrent branch of the median nerve and to
define its course with respect to the distal edge of the transverse carpal
ligament (TCL). The spatial orientation, number, and course of the recurrent
branch was carefully determined. Calipers were used to measure the distance
between the recurrent branch and the TCL. Histologic analysis of the fascia
surrounding the recurrent nerve was performed. The recurrent branch of the median
nerve was classified into 3 types. Type I passed through the TCL; it is rare,
occurring in 7% of the specimens. Type II nerves (74%) passed distal to the TCL
through separate obliquely oriented fascia that originated on the TCL and
inserted on the undersurface of the palmar aponeurosis. Type 111 (19%) passed
distal to the TCL, but did not pass through the obliquely oriented fascia. The
distance from the distal edge of the TCL was significantly different between the
3 types. Ninety-nine percent of recurrent branches originated either from the
central portion of the median nerve or just radial to it. There were no ulnar
origins. Four cadavers (4%) had more than 1 recurrent branch. The variability in
the literature on the anatomy of the recurrent branch can be accounted for by
failure to properly identify the TCL as being separate from the obliquely
oriented fascia distal to the TCL through which the nerve frequently penetrates.
Histologic analysis confirmed a difference between the TCL and these oblique
fibers that can surround the recurrent nerve. This study concludes that the
transligamentous branch (type I) is uncommon and the reported high incidence of
branches passing through the TCL can be explained by mistakenly combining
recurrent nerve types I and II.
PMID- 9763262
TI - Differential latency testing: a more sensitive test for radial tunnel syndrome.
AB - A modification of the standard electrodiagnostic test was developed in an effort
to provide a more sensitive electrodiagnostic evaluation in radial tunnel
syndrome. Radial motor nerve latency recordings were obtained in 3 different
forearm positions: neutral, passive supination, and passive pronation. The
maximal difference in these recordings, the differential latency, in 25 patients
with radial tunnel syndrome of greater than 6 months duration (test group) was
compared with those in 25 asymptomatic volunteers (control group). Differential
latency recordings were obtained in all patients in the test group before and
after surgery. Radial nerves that were compressed demonstrated a significantly
greater differential latency (0.44+/-0.12 ms) versus controls (0.12+/-0.008 ms).
Following radial nerve decompression, differential motor latencies in the test
group decreased below control values, demonstrating a resolution of the provoked
electrical response with a postoperative differential latency of 0.07+/-0.05 ms.
Our results demonstrate the differential motor latency of the radial nerve to be
a sensitive electrodiagnostic tool in patients with radial tunnel syndrome. A
differential latency of > or =0.30 ms was considered indicative of radial tunnel
syndrome.
PMID- 9763263
TI - The results of revision carpal tunnel release following previous open versus
endoscopic surgery.
AB - This study compared the outcomes of revision open carpal tunnel release following
previous open versus endoscopic release to determine whether revision surgery has
different results based on the type of initial surgical treatment. Thirty
revision carpal tunnel releases were performed in 13 wrists that had previous
endoscopic release and in 17 wrists with prior open release. At a follow-up visit
an average of 30 months after surgery, self-assessment questionnaires
demonstrated improved or complete symptom relief in 77% of the postendoscopic
release group versus 47% in the previous open release group. Combining both
groups, 18% of workers' compensation patients improved after revision surgery
compared with 84% of those with conventional insurance (p < .05). Patients having
persistent or recurrent symptoms following a previous endoscopic carpal tunnel
release have a greater chance of symptom improvement or resolution compared with
patients who had previous open carpal tunnel surgery. Our results support the
observation that a higher incidence of incomplete release of the carpal tunnel is
found with endoscopic surgery than with open release.
PMID- 9763264
TI - Distance between the median nerve and ulnar neurovascular bundle: clinical
significance with ultrasonographically assisted carpal tunnel release.
AB - In ultrasonographically assisted carpal tunnel release, the zone of the
transverse carpal ligament between the median nerve and ulnar neurovascular
bundle is of significance because proximity of the cutting device to these
structures depends on its width. In this study, we measured the width of the zone
at 5 levels in 60 wrists from 54 patients with surgery-indicated idiopathic
carpal tunnel syndrome. The width of the 5 levels ranged from 2.8 to 11.2 mm
(mean, 7.1 mm) at the hook of the hamate, 3.0 to 12.5 mm (mean, 7.9 mm) at the
distal one fourth of the carpal tunnel, 2.8 to 12.4 mm (mean, 8.0 mm) at the
midsection of the tunnel, 1.5 to 13.0 mm (mean, 7.4 mm) at the proximal one
fourth of the tunnel, and 5.3 to 17.2 mm (mean, 10.2 mm) at the wrist crease.
These widths were not significantly correlated with radiographic measurements of
the hand (cord of the radiocarpal joint arc, carpal height, third metacarpal, and
hand length). We conclude that there is considerable variation of the width among
individuals. Based on our clinical experience (3 wrists of 3 patients in this
study), patients with a width of < or =3 mm at any level should be screened out
preoperatively by wrist imaging. Our findings also may be of use to surgeons
performing endoscopic carpal tunnel release.
PMID- 9763265
TI - Malignant melanoma extending along the ulnar, median, and musculocutaneous
nerves: a case report.
AB - We analyzed a case of malignant melanoma that resembled malignant peripheral
nerve sheath tumor with marked neurotropism. The subungual tumor in the right
ring finger extended along the ulnar nerve for a distance of 30 cm, as well as
along the median and musculocutaneous nerves, with lymph nodal metastases. The
tumor consisted of interlacing spindle-shaped cells with large nuclei and
distinct nucleolei. Immunohistochemically, the tumor cells were diffusely
positive for S-100 protein. Five years after forequarter amputation, the patient
is alive without disease. Malignant melanoma has the potential of invading
several major peripheral nerves and must be distinguished from malignant
peripheral nerve sheath tumor, which rarely metastasizes to regional lymph nodes.
PMID- 9763266
TI - First metacarpal subsidence during pinch after ligament reconstruction and tendon
interposition basal joint arthroplasty of the thumb.
AB - Trapeziectomy, ligament reconstruction and tendon interposition arthroplasty is
one of the most commonly performed procedures to address pain and instability due
to osteoarthritis at the basal joint of the thumb. To determine the effect of
stress on first metacarpal subsidence, 15 ligament reconstruction and tendon
interposition basal joint arthroplasties were evaluated after a mean follow-up of
32 months. Radiographs were obtained of the arthroplasty at rest and then with
maximal effort key pinch stress, which is known to subject the first
carpometacarpal joint to considerable axial compression stress. Compared with the
preoperative x-rays, the first metacarpal had subsided 21% of the arthroplasty
space at rest. Under stress, the first metacarpal was found to subside another
10.5% in height. No subluxation of the metacarpal base could be detected. Key
pinch strength improved 17% from the preoperative strength. Tip-to-tip pinch
strength improved 17% from the preoperative measurement. Grip strength improved
17% from the preoperative measurement. Grip strength was 9% greater than the
preoperative grip strength. There was no statistical association between the
amount of first metacarpal subsidence and follow-up key pinch, tip pinch, or grip
strength. With axial compressive loading of the arthroplasty, such as in lateral
pinch, there is some further proximal migration of the first metacarpal, but this
is minimal and does not correlate with functional outcome.
PMID- 9763267
TI - Reconstruction of the scapholunate ligament in a cadaver model using a bone
ligament-bone autograft from the foot.
AB - This study is an investigation of a new procedure in which the scapholunate
interosseous ligament (SLIL) is reconstructed using a bone-ligament-bone
autograft from the foot. After investigation, the dorsal medial portion of the
navicular-first cuneiform ligament (NFCL) was chosen for testing as a potential
donor since it is similar in length and thickness to the SLIL and it is easily
harvested with minimal potential donor site morbidity. Eight SLILs and NFCLs were
harvested from fresh-frozen cadavers. Biomechanical extensometry testing was
performed using an Instron 1000 machine. A 5-mm-wide central portion of the NFCL
was tested since this width was compatible with the technical aspects of
reconstructing the SLIL. Both ligaments were tested for elastic properties,
including stiffness, load to failure, and deformation to failure. Mean length of
the NFCL was 7.6 mm (range, 5.5-8.5 mm). Stiffness of the NFCL was 10.6 x 10(5)
Nm (range, 8.0-13.0 Nm) compared with 14.4 x 10(5) Nm for the SLIL (range, 10.0
19.5 Nm). Peak load to failure for the NFCL was 1,980 N (range, 1,530-2,940 N)
compared with 2,940 N for the SLIL (range, 1,780-4,050 N). Total elongation to
failure for the NFCL was 2.50 mm (range, 1.7-3.2 mm) compared with 3.2 mm for the
SLIL (range, 2.1-5.2 mm). Thus, the biomechanical characteristics of the NFCL
were found to be very similar to those of the SLIL. Having established the
biomechanical similarities of the 2 ligaments, we are currently using the NFCL to
reconstruct the sectioned SLIL in a fresh-frozen cadaver model. Early results
suggest that this procedure is feasible for restoration of normal kinematics of
the wrist.
PMID- 9763268
TI - Wrist arthrodesis after failed wrist implant arthroplasty.
AB - Wrist arthroplasty has not achieved large success to date, and there are patients
with failures in their procedures who will need arthrodesis. We review our
experience in revising a wrist implant arthroplasty to an arthrodesis with a
block graft of fresh-frozen allograft femoral head or iliac crest bone graft.
Fixation was achieved with an intramedullary Steinmann pin. Ten patients with 12
failed wrist implants required wrist arthrodesis; 7 had wrist arthrodesis with a
bulk allograft femoral head, 4 with an iliac crest bone autograft, and 1 without
a bone graft. After an average follow-up period of 5 years, all patients were
pain free and fusion had been achieved. Complications included 1 patient with
acute carpal tunnel syndrome, 2 patients with nonunions requiring secondary bone
grafting procedures, and 2 patients requiring revisions of their intramedullar
pins. In both nonunions, iliac crest bone graft was used for the initial
arthrodesis. All the patients were satisfied. Arthrodesis after failed wrist
implant arthroplasty is a satisfactory procedure, and a fresh-frozen allograft
can be used effectively in wrist fusion.
PMID- 9763269
TI - Arthroscopic evaluation of radial osteotomy for Kienbock's disease.
AB - To determine whether osteoarthritic changes of the perilunate articular cartilage
improve following radial osteotomy for Kienbock's disease and correlate with
clinical results, arthroscopic examination was performed in 18 patients
concurrently with radial osteotomy and at the time of removal of implants after
an average of 21 months. Clinical results were satisfactory. All patients
improved the preoperative level of pain. Wrist function was improved in range of
motion and grip strength. Radiographic findings also demonstrated prevention of
further collapse of the lunate. However, follow-up arthroscopic examination
revealed progression of osteoarthritis in the area of the lunate in two thirds of
the cases. There was no correlation between arthroscopic observations and
clinical results. A long-term follow-up period is therefore advocated for
evaluation of radial osteotomy because of the possibility of additional
progression of osteoarthritic changes.
PMID- 9763271
TI - Pressure distribution in the distal radioulnar joint.
AB - Measurement of the pressure distribution within the distal radioulnar joint was
performed in fresh cadaver forearms at varying positions of forearm rotation.
Axial loads of 0 N, 36 N, and 89 N were applied to the wrist flexors and
extensors. At neutral forearm rotation and application of 89 N axial load, an
average of 12.5% of the sigmoid notch area was in contact with the ulna. Analysis
of the pressure plots reveals that in pronation, the pressure was concentrated in
the dorsal portion of the sigmoid notch and that in supination the pressure was
distributed in the palmar portion.
PMID- 9763270
TI - Ulnar shortening for triangular fibrocartilage complex tears associated with
ulnar positive variance.
AB - Twenty-five patients with triangular fibrocartilage complex (TFCC) tears
associated with ulnar positive variance who did not respond to conservative
management were treated by ulnar shortening. The follow-up period averaged 35
months. All patients complained of pain, restricted forearm rotation, and
weakness of grip. Arthroscopy was performed in 23 of 25 wrists to assess the
status of the TFCC and the degree of the degenerative change of the proximal
aspect of the lunate and triquetrum. Arthroscopic findings consisted of 15 class
1 and 8 class 2 tears according to Palmer's classification. When the TFCC showed
a traumatic flap tear, only the torn flap was removed arthroscopically. Ulnar
shortening averaged 3 mm. Transverse osteotomies healed in all patients at a mean
postoperative time of 7 weeks. Twenty-three patients had either complete relief
or occasional mild pain of the wrist. Two patients with persistent pain had
additional procedures performed. Postoperative x-ray films revealed slight
degenerative changes at the distal radioulnar joint in 7 patients. Complications
included 1 reflex sympathetic dystrophy and 2 fractures through the osteotomy
site after early plate removal. Ulnar shortening is a useful procedure for TFCC
tears associated with ulnar positive variance.
PMID- 9763272
TI - Un-united fractures of the distal radius: a report of 12 cases.
AB - The treatment of 12 distal radius nonunions in 11 patients over a 24-year period
is presented. The average age of the patients was 55 years (range, 35-72 years).
The comorbid medical conditions in the patients with these fractures included
diabetes mellitus, peripheral vascular disease, psychiatric disorders,
alcoholism, peripheral neuropathy, scleroderma, and morbid obesity. Nine of the
un-united fractures in 8 patients had insufficient metaphyseal bone to allow
internal fixation; 6 of these fractures were treated with a wrist arthrodesis.
Three un-united fractures in 3 patients had sufficient supporting bone to permit
correction of the nonunion and preservation of the radiocarpal joint. Three
nonunions in 3 patients were treated without further surgery. Bony union was
achieved in all 9 nonunions managed operatively (6 wrist arthrodeses and 3 open
reductions).
PMID- 9763273
TI - Recurrent dorsal angulation of the distal radius fracture during dynamic external
fixation.
AB - Thirty-three fractures of the distal radius treated with a dynamic external
fixator (that allowed for wrist motion between 2 to 4 weeks after surgery) were
analyzed, focusing on loss of fracture reduction during external fixation.
Fractures with preoperative dorsal angulation greater than 20 degrees and those
involving the distal radioulnar joint had a significantly larger loss of
reduction of dorsal angulation (8.9 degrees and 6.9 degrees, respectively) than
fractures with less severe preoperative dorsal angulation or those with an intact
distal radioulnar joint (3.0 degrees and 2.6 degrees, respectively). In contrast,
preoperative radial shortening (>2 mm) and involvement of the radiocarpal joint
did not significantly increase the loss of dorsal angulation. Neither of the 2
dynamic external fixation systems studied consistently stabilized Colles'
fractures with preoperative dorsal angulation of greater than 20 degrees or
involvement of the distal radioulnar joint.
PMID- 9763274
TI - Load relaxation and forces with activity in Hoffman external fixators: a clinical
study in patients with Colles' fractures.
AB - A small-frame Hoffman external fixation bar instrumented with strain gauges to
quantify bending and torsional forces was applied to 4 patients with a displaced
metaphyseal fracture of the distal radius. Measurements were taken during surgery
as well as at 1, 3, and 6 weeks after surgery during activities of daily living
and hand therapy mobilization. Radiographs also were taken before and after
reduction and at each subsequent visit. Force decay occurred after reduction of
the fracture, averaging only 26% of the initial distraction forces by 5 minutes.
These forces plateaued and did not significantly change over the subsequent 40
minute observation period. There was no correlation between carpal height index
and the forces measured in the external fixator. Significant changes in external
fixator forces were measured during activities of daily living and hand therapy
mobilization, but these returned to baseline after the activities were performed.
The most provocative activities studied were twisting a doorknob and lifting
heavy objects. These activities should be performed with caution by patients with
unstable distal radial fractures.
PMID- 9763275
TI - Pseudoaneurysm of the ulnar artery occurring after fracture of the distal radius
and ulna: a case report.
AB - A case of pseudoaneurysm of the ulnar artery occurring after distal radius and
ulna fracture is presented. This case illustrates an uncommon complication
following a fairly common injury.
PMID- 9763276
TI - Forearm muscle activation during power grip and release.
AB - The position of the hand during power grip is well-described, but the normal
phasic activity of the extrinsic forearm muscles during power grip and release is
unknown. People with neurologic impairment may have inadequate power grip or
release because of abnormal muscle timing. This study describes the timing of the
forearm muscles in 10 normal subjects during power grip and release, which was
evaluated using electromyography. During power grip, subjects had consistent
timing patterns for extrinsic finger motors and different but individually
consistent patterns for wrist motors. This finding supports our hypothesis that
different individuals habitually use a specific motor strategy and an intact
central nervous system allows them to change their motor strategy to adapt to new
environmental parameters.
PMID- 9763277
TI - The effect of shear stress on fibroblasts derived from Dupuytren's tissue and
normal palmar fascia.
AB - This study examines the real-time intracellular calcium changes of palmar fascia
from normal and Dupuytren's diseased fibroblasts in response to shear stress. The
real-time cytosolic calcium changes were measured using fluorescence microscopy
image processing. The preconfluent primary cultured cells were exposed to 1
minute of flow at 25 dyne/cm2 after a 2-minute baseline of no flow. Additionally,
the cells were exposed to an influx of Hank's buffered saline solution with 2%
newborn bovine serum to examine the response to serum-born (chemical) agonists.
Cytosolic calcium changes were measured as the percentage change over the 2
minute baseline of the mean [Ca2+]i peak. The mean change of the peak [Ca2+]i
response of the normal palmar fascia was significantly greater than that of the
cells from the Dupuytren's nodular and perinodular tissue. The response to the
chemical agonist showed a robust but not statistically different response between
the 3 cell types. Our work supports the hypothesis that palmar fascia responds to
mechanical stress, specifically laminar fluid flow. These findings may help to
explain that an underlying abnormality in the cells of the palmar fascia may be
expressed by exposure to laminar fluid flow, a physical signal, rather than a
chemical agonist.
PMID- 9763278
TI - Simplified Sauve-Kapandji procedure.
PMID- 9763279
TI - Unit of measurement: newton (N) versus kilogram force (kgf)
PMID- 9763282
TI - Staged opposition transfer.
PMID- 9763281
TI - Pain responses in patients with upper-extremity disorders.
PMID- 9763280
TI - Pain responses in patients with upper extremity disorders.
PMID- 9763283
TI - Physeal growth arrest of the distal phalanx of the thumb in an adolescent
pianist: a case report.
PMID- 9763284
TI - Organisation and informational content of the Theileria parva genome.
AB - When compared with other Apicomplexan organisms, Theileria parva has an
exceptionally small, 10-12 Mbp, genome. There are only 4 chromosomes, each in the
Mbp range, and a complete physical map, based on SfiI linking data, is available
for each one. A number of genes and cDNAs have been mapped to specific SfiI
fragments. Telomeres consist of the simple repeat sequence typical of chromosomal
ends but sub-telomeric homologies do not extend beyond 5 kbp. The only dispersed
repetitive sequences identified to date are minisatellites, but these are found
on a subset of SfiI fragments. There are clusters of distinct multicopy sequences
which contain ORFs. However, the majority of parasite protein coding genes are
present in a single copy. They have a compact structure, exhibit a bias in codon
usage and non-translated regions are small. Introns, if present, are unusually
short. Overall, the genome contains remarkably little repetitive, non-coding DNA.
The parasite mitochondrial DNA is linear in structure, has a limited protein
coding capacity and fragmented rRNA genes and its telomeres contain inverted
repeat sequences.
PMID- 9763285
TI - Characterization of developmentally-regulated activities in axenic amastigotes of
Leishmania donovani.
AB - Leishmania donovani is an obligatory intracellular parasite which cycles between
the midgut of sand flies (extracellular promastigote) and the phagolysosomes of
mammalian macrophages (intracellular amastigote). Promastigotes have been readily
cultured, whereas axenic cultures of amastigotes have only recently been
developed. A new method for in vitro differentiation of L. donovani promastigotes
into amastigotes is presented, in which promastigotes are exposed to
environmental changes that mimic the in vivo process. First, promastigotes are
subjected to 37 degrees C + 5% CO2 for 24 h, and then are shifted to pH 5.5.
Under these conditions, differentiation is completed within 120 h. In the reverse
process, amastigotes are induced to differentiate back to promastigotes by
transferring them to promastigote growth conditions (medium 199 at pH 7.4 and 26
degrees C). Axenic amastigotes closely resemble animal-derived amastigotes. They
manifest all seven proteins of the amastigote-specific A2 gene family. They down
regulate lipophosphoglycan (LPG) synthesis and do not express it on their
surface. LPG is up-regulated 2 h after inducing amastigotes to differentiate to
promastigotes. Within 6 h, parasites resume the promastigote level of this
molecule, although differentiation is completed only after 48 h. Axenic
amastigotes also express amastigote-like metabolic activities of proline uptake,
as well as thymidine and proline incorporation. In conclusion, the results
indicate that the method developed for in vitro differentiation of L. donovani
promastigotes to amastigotes is efficient and yields organisms resembling animal
derived amastigotes. Being able to induce in vitro differentiation of L. donovani
provides us with an excellent tool to study Leishmania development and
differentiation.
PMID- 9763286
TI - Characterisation of a Cryptosporidium parvum-specific cDNA clone and detection of
parasite DNA in mucosal scrapings of infected mice.
AB - A cDNA library was constructed using total RNA extracted from oocysts and
sporozoites of the protozoan parasite Cryptosporidium parvum. The expression
library was screened with an anti-C. parvum antiserum and a clone, Cp3.4, with a
2043 bp insert, was extracted. Southern blot analysis demonstrated a single copy
gene that was located on a 1.6 Mb chromosome. The gene was found to be C. parvum
specific as Cp3.4 did not cross-hybridise with chromosomal DNA from three other
apicomplexan parasites. The cDNA encodes a polypeptide with a predicted membrane
helix at its C-terminal end which is flanked by stretches of acidic amino acids.
Overall, the polypeptide has a low isoelectric point (pI) of 3.94. A total of 21
glycine/proline-rich octapeptides were identified which represented variations of
a consensus sequence. The function of this protein is yet unknown. Using Cp3.4
specific PCR primers, this C. parvum gene could be amplified from as little as
0.8 pg of purified parasite DNA in a single polymerase chain reaction. Less than
0.1 ng of DNA from the ileum mucosa of immunosuppressed adult mice that had been
infected with C. parvum oocysts was required to detect the parasites. In non
immunosuppressed mice that were infected and which did not shed oocysts in
numbers detectable by acid-fast staining, parasite development could be detected
in 25 ng of total mucosa DNA. This PCR approach may be a valuable technique for
the detection of parasite infections in situations where conventional staining
methods fail, such as chronic, low-grade infections or the detection of parasites
in potential reservoir hosts.
PMID- 9763287
TI - Phylogenetic analysis of Theileria and Babesia equi in relation to the
establishment of parasite populations within novel host species and the
development of diagnostic tests.
AB - The divergence of parasites is important for maintenance within an established
host and spread to novel host species. In this paper we have carried out
phylogenetic analyses of Theileria parasites isolated from different host
species. This was performed with small subunit ribosomal RNA sequences available
in the data bases and a novel sequence amplified from Theileria lestoquardi DNA.
Similar phylogenetic studies were carried out with sequences representing the
major merozoite/piroplasm surface antigen (mMPSA) from the data base, and novel
sequences representing 2 mMPSA alleles from T. lestoquardi, a full length
sequence of a Theileria taurotragi mMPSA gene and partial sequences of two new
allelic variants of the Babesia equi mMPSA gene homologue. The analysis indicated
that the pathogenic sheep parasite T. lestoquardi has most probably evolved from
a common ancestor of T. annulata. Interestingly, the level of mMPSA sequence
diversity found for T. lestoquardi was surprisingly low, while diversity between
the B. equi sequences was higher than that found within any of the classical
Theileria species. The possible implications of these results for the
establishment of Theileria parasites within novel species are discussed.
Extensive cross-reactivity of a range of antisera was found when tested against
recombinant mMPSA polypeptides from different Theileria (including B. equi)
species. The cross-reactivity between mMPSA polypeptides and sequence diversity
are relevant for the development of species specific diagnostic tests.
PMID- 9763288
TI - Hgm1, a novel male-specific gene from Heterodera glycines identified by
differential mRNA display.
AB - The plant parasitic nematode Heterodera glycines is amphimictic: populations
consist of both male and female individuals that reproduce sexually. However,
under conditions of environmental stress, unbalanced male and female sex ratios
are found. This observation requires an explanation of how sexual fate is
determined in these nematodes. As a step towards identifying genes that are
differentially regulated between male and female nematodes we have used cDNA
differential display to screen for male-specific cDNA sequences. These studies
have led to the isolation of a full-length male specific cDNA, Hgm1, that is up
regulated in H. glycines males. Sequence analysis of this cDNA reveals that it
represents a novel gene which encodes a 49.5 kDa acidic protein with a pI of 4.72
and a predicted 21 amino acid leader sequence. Neither the nucleotide nor the
predicted amino acid sequence of this gene show any homology to sequences in the
databases suggesting that Hgm1 is a previously uncharacterised gene. Here we
report the isolation, molecular characterisation and expression profile of Hgm1.
PMID- 9763289
TI - Biochemical and molecular properties of the Trypanosoma brucei alternative
oxidase.
AB - The protozoal parasite Trypanosoma brucei depends on a mitochondrial non
cytochrome terminal oxidase known as the trypanosome alternative oxidase (TAO) in
its mammalian host. We have recently cloned the cDNA from T. brucei bloodstream
form and have characterized a 33 kDa mitochondrial protein as TAO. Here we report
that the TAO is a single copy gene in T. brucei and its expression is down
regulated at the level of transcript abundance during differentiation from the
bloodstream to the procyclic trypanosomes. Like other alternative oxidases (AOXs)
cloned from different plants and fungi, TAO possesses the conserved sequences at
the centrally located predicted membrane spanning domains and the signature
sequence at the C-terminal hydrophilic domain for a pair of putative iron binding
motifs (E-X-X-H). Phylogenetic analysis of the deduced protein sequences of eight
different alternative oxidases cloned from different plants and fungi revealed
that TAO is more closely related to the alternative oxidases of the fungi clade
than that of plants. TAO has been functionally expressed in Escherichia coli. In
the first of the two putative iron binding motifs, site-directed mutagenesis of
E215 to A, L, N and Q resulted in the loss of the ability of the TAO gene to
complement the heme deficiency of the E. coli mutants (SASX41B and GE1387) by
conferring on them a CN-insensitive pathway of respiration. The conservative
substitution of E215 by aspartate and histidine reduced the growth of the E. coli
auxotrophs by approximately 80%. The mutations apparently did not have any effect
on the stability of the expressed protein as revealed by the immunoblot analysis
of the bacterial protein using TAO monoclonal antibody, which we have developed.
Together, these points suggest that E215 plays an important role in the function
of TAO. The steady state level of TAO mRNA is down-regulated in the procyclic
stage presumably accounting for the low levels of TAO protein in these forms.
PMID- 9763290
TI - Divergent evolutionary constraints on mitochondrial and nuclear genomes of
malaria parasites.
AB - Genetic variation among malaria parasites has important consequences with regard
to drug resistance, pathogenicity, immunity, transmission, and speciation. In
this regard, malaria parasites have been shown to display a high degree of inter-
and intra-species genetic divergence. The nuclear genomes of Plasmodium
falciparum, Plasmodium yoelii, and Plasmodium gallinaceum are vastly divergent
yet share a similar codon usage and total A/T content of approximately 82%. This
is in contrast to other primate-specific species including P. vivax which have an
A/T content of approximately 67%. To assess the effects of this evolutionary
divergence on the conservation of gene content, organization, and codon usage in
the mitochondrial DNA (mtDNA) of malaria parasites, we have cloned and sequenced
the mitochondrial genome of Plasmodium vivax, and compared it with the mtDNAs of
P. falciparum, P. yoelii, and P. gallinaceum. The P. vivax mitochondrial genome
was found to be 5990 base pairs in length, and displayed a gene organization
identical to that of P. falciparum, P. yoelii, and P. gallinaceum. Furthermore,
there was a remarkable 90% conservation of sequence identity between the
mitochondrial genomes of all four species. As an example of intra-species
conservation, comparison of mtDNAs from two independently cloned P. falciparum
isolates, Malay Camp and C10, revealed only a single nucleotide substitution. A/T
content of the P. vivax mitochondrial genome was found to be identical to other
species of Plasmodium, hence, we have postulated that the mitochondrial genomes
of malaria parasites were refractory to the evolutionary shifts in nucleotide
content seen among the nuclear genomes of malaria parasites. Among different
Plasmodium species, the second position of mitochondrial codons were found to be
the least prone to substitutions and displayed a significant bias in pyrimidines.
These aspects of mitochondrial codon usage were distinct from the nuclear genome
and may reflect functional aspects of decoding by the mitochondrial translational
system.
PMID- 9763291
TI - Identification of stage-regulated and differentiation-enriched transcripts during
transformation of the African trypanosome from its bloodstream to procyclic form.
AB - Trypanosoma brucei undergoes dramatic stage-specific changes in surface antigen
expression, metabolic development, cellular morphogenesis and cell-cycle control.
These events can be studied in detail during the transition between the
bloodstream stumpy stage and the tsetse fly midgut procyclic form. This
differentiation can be induced in vitro, is synchronous in the population and
there are abundant markers for stage-regulated and differentiation events. We
have used this differentiation system to investigate the role of de novo
transcription during different phases of this well-characterised cellular
transformation. Our experiments implicate early transcriptional involvement in
shedding of the variable surface glycoprotein coat, cell restructuring and cell
cycle re-entry. The synchrony of differentiation has also been exploited to
identify transcripts which define distinct regulated processes during this
differentiation. The transcripts identified provide good coverage of the
different molecular regulation events that accompany this life-cycle
transformation. These included a surface antigen gene (encoding procyclin/PARP),
a cell cycle regulated component (encoding histone H2B), a homologue of the
Leishmania activated protein kinase C receptor (LACK) and a putative gene for sub
unit VI of cytochrome c oxidase.
PMID- 9763292
TI - Selection for activation of a new variant surface glycoprotein gene expression
site in Trypanosoma brucei can result in deletion of the old one.
AB - The African trypanosome Trypanosoma brucei expresses the active variant surface
glycoprotein (VSG) gene in a telomeric VSG gene expression site. We have
generated trypanosomes with a neomycin resistance gene inserted behind an active
VSG gene expression site promoter, and a hygromycin resistance gene behind a
silent one. By alternating drug selection, we could select for trypanosomes that
had switched between the two marked VSG gene expression sites. Surprisingly,
trypanosomes that had activated a new VSG gene expression site had often lost the
old one. Using polymerase chain reaction (PCR), we screened large numbers of
switched trypanosomes and found that sequences lost invariably included the drug
marker near the promoter, as well as the telomeric VSG gene many tens of
kilobases away. We postulate that stable activation of a new expression site
requires silencing of the old one. If silencing does not occur at a sufficient
rate by normal switch-off, stable activation of the new site can only occur if
the old site is lost in random deletion events. The fact that we pick up these
normally infrequent deletions, indicates that inactivation of the old VSG
expression site could be rate limiting during switching in our strain of T.
brucei.
PMID- 9763294
TI - The mini-exon gene: a genetic marker for zymodeme III of Trypanosoma cruzi.
PMID- 9763293
TI - The mitochondrial genome of Onchocerca volvulus: sequence, structure and
phylogenetic analysis.
AB - The complete DNA sequence of the mitochondrial genome of Onchocerca volvulus is
described. The O. volvulus mitochondrial genome is 13747 bp, slightly smaller
than the mitochondrial genomes of the nematodes Ascaris suum and Caenorhabditis
elegans, and the smallest metazoan mitochondrial DNA molecule reported to date.
The O. volvulus mitochondrial genome contains genes for two ribosomal RNAs, 22
transfer RNAs and 12 proteins. Consistent with the small size of the genome, four
gene pairs overlap and eight contain no intergenic regions. Only 17 intergenic
regions are found, ranging in size from 1 to 46 bp. As in C. elegans and A. suum,
the O. volvulus mitochondrial genome lacks an open reading frame encoding ATPase
subunit 8, and all genes are apparently transcribed in the same direction.
However, the mitochondrial gene order of O. volvulus differs from that of A.
suum, C. elegans and other metazoan mitochondrial genomes. A total of 20 of the
22 transfer RNAs encoded in the O. volvulus mitochondrial genome have the
potential to fold into secondary structures lacking the TpsiC arm, as has been
reported in other nematodes. The genome exhibits a striking codon bias, with
15/20 amino acids having a single codon preference of > 70%.
PMID- 9763295
TI - Purification and characterization of UDP-N-acetylglucosamine pyrophosphorylase
from encysting Giardia.
PMID- 9763297
TI - Construction and characterisation of a genomic PAC library of the intestinal
parasite Cryptosporidium parvum.
PMID- 9763296
TI - Cloning and characterization of Leishmania tarentolae adenine
phosphoribosyltransferase.
PMID- 9763298
TI - Plasmodial serine repeat antigen homologues with properties of schizont cysteine
proteases.
PMID- 9763299
TI - Telomeric features of Theileria parva mitochondrial DNA derived from cycle
sequence data of total genomic DNA.
PMID- 9763300
TI - An RCC1-type guanidine exchange factor for the Ran G protein is found in the
Plasmodium falciparum nucleus.
PMID- 9763301
TI - Adenylate cyclases in keratinocytes: FRSK cells express types I, II, III, IV, VI
and VIII, and 1,25(OH)2D3, retinoic acid and TPA augment forskolin-induced cyclic
AMP accumulation in the absence of altered isozyme expression.
AB - Molecular cloning analysis has detected at least nine adenylate cyclase isozymes
in mammalian tissues. Using fetal rat skin keratinocytes (FRSK), we investigated
adenylate cyclase expression and its modulation by 1,25-dihydroxyvitamin D3
(1,25(OH)2D3), a retinoid (Ro10-1670), and 12-O-tetradecanoylphorbol-13-acetate
(TPA). Reverse transcription polymerase chain reaction (RT-PCR) indicated that
FRSK contain adenylate cyclases I, II, III, IV, VI and VIII. Treatment with
1,25(OH)2D3 (1 x 10(-7) M), Ro10-1670 (1 x 10(-6) M), and TPA (100 ng/ml)
resulted in increased forskolin-induced cyclic AMP accumulation by FRSK cells and
normal human keratinocytes (NHK). Quantitative RT-PCR and Western blot analysis,
however, detected no alteration in mRNA and protein levels of each adenylate
cyclase isozyme for at least 48 h. These results indicate that FRSK contain at
least six (I, II, III, IV, VI and VIII) adenylate cyclase isozyme mRNAs,
suggesting a complex regulatory mechanism of cyclic AMP generation in
keratinocytes. Although 1,25(OH)2D3, Ro10-1670, and TPA augmented forskolin
induced cyclic AMP accumulation, they do not seem to affect the expression of
specific adenylate cyclase isozymes by FRSK cells.
PMID- 9763302
TI - Inhibition of skin 11beta-hydroxysteroid dehydrogenase activity in vivo
potentiates the anti-inflammatory actions of glucocorticoids.
AB - Synthetic forms of glucocorticoids (GCs) with high potency are widely used to
treat a number of dermatological conditions having an inflammatory or autoimmune
etiology. While GCs are generally effective in their ability to suppress
inflammatory processes, their chronic use can lead to detrimental systemic side
effects. In this report, we describe a method by which the localized
antiinflammatory potential of the natural GC cortisol can be significantly
augmented without increasing the risk of negative systemic effects. 11Beta
hydroxysteroid dehydrogenase (11beta-HSD) is a naturally occurring enzyme in the
skin. 11Beta-HSD functionally converts biologically active 11-hydroxy GCs to
their biologically inactive 11-keto metabolites, thereby limiting the ability of
GCs to mediate antiinflammatory activities. By topically applying specific
inhibitors of 11beta-HSD in conjunction with low doses of GCs, the
antiinflammatory properties of cortisol can be significantly potentiated. It was
observed that the generation of the effector phase of contact hypersensitivity
(CH) responses could be suppressed by this combined treatment under conditions
where the 11beta-HSD inhibitor alone, or cortisol alone were only minimally
effective. Only the combined treatment was effective at inhibiting the
progression of an ongoing CH response.
PMID- 9763303
TI - Differential response of basal keratinocytes in a human skin equivalent to
ultraviolet irradiation.
AB - The human skin equivalent (HSE) provides a convenient model system for studying
the cellular responses of basal keratinocytes to UV irradiation. HSEs,
constructed by overlaying a collagen-fibroblast matrix with epidermal cells, were
raised to an air-liquid interface to promote epidermal differentiation. HSEs were
exposed to ultraviolet radiation from a 500-W Hot Quartz Hanovia therapeutic
sunlamp, at a total dose of 100 J/m2. The HSEs were then frozen every 4 h over a
48-h period and cryosectioned. For each time period, the expression of beta1
integrin and cyclin E, p53, or Bcl-2 were quantified using dual
immunolocalization. Basal cells expressing beta1 integrin were divided into two
subpopulations, denoted beta1high or beta1low. The proportion of beta1high
keratinocytes expressing Bcl-2 and cyclin E increased significantly 4 and 8 h,
respectively, after exposure to UV; during the subsequent 16 h, this basal cell
subpopulation expressed p53. By contrast, significant numbers of beta1low basal
keratinocytes expressed p53, but not Bcl-2. These results suggest that beta1high
and beta1low populations of basal epidermal cells in HSEs respond differently to
UV irradiation.
PMID- 9763304
TI - Alpha-MSH regulates interleukin-10 expression by human keratinocytes.
AB - Normal human keratinocytes (HKC) are able to synthesize alpha-MSH. Because the
production of alpha-MSH by HKC is induced significantly by ultraviolet B
radiation, the involvement of keratinocyte-derived alpha-MSH in UV-induced
immunosuppression has been suggested. The induction of the antiinflammatory
cytokine IL-10 in monocytes is a major mechanism in the antiinflammatory actions
of alpha-MSH. In the present study, HKC were investigated for their ability to
produce IL-10 after alpha-MSH stimulation. HKC were obtained from the skin of
human female breast sections and either left untreated or treated with 0.01 or
0.1 microg/ml alpha-MSH for different times. Using RT-PCR, HKC were shown to
express IL-10 mRNA even under basal conditions, and treatment with alpha-MSH
increased expression. Only minimal concentrations of IL-10 protein were detected
in supernatants from the alpha-MSH-stimulated cultures. To the best of our
knowledge this is the first report of IL-10 expression by cultured HKC after
alpha-MSH stimulation. Further studies are needed to determine the biological and
therapeutic relevance of these findings.
PMID- 9763305
TI - Histamine enhances UVB-induced IL-6 production by human keratinocytes.
AB - Histamine, an important mediator in immediate-type hypersensitivity, is elevated
in the skin of patients with atopic dermatitis and is considered to play a
pathogenic role in atopic dermatitis. In this study, to elucidate the mechanism
of sun exposure-induced exacerbation of skin lesions in atopic dermatitis, we
examined the effect of histamine on proinflammatory cytokine production of
keratinocytes induced by ultraviolet (UV) B irradiation. Cultured human
keratinocytes were irradiated with 30 mJ/cm2 of UVB and incubated with histamine
over the concentration range 10(-7) to 10(-4) M, and the IL-1alpha and IL-6
released into the medium were measured using an ELISA. Histamine weakly
stimulated IL-6 production by itself. However, together with UVB, it
synergistically enhanced IL-6 production and the amount of IL-6 mRNA as estimated
by reverse-transcription polymerase chain reaction (RT-PCR). Histamine had a dose
dependent effect which was maximal at a concentration of 10(-5) M, and had no
effect on the kinetics of IL-6 production. In contrast, histamine had no effect
on IL-1alpha production by keratinocytes. The effect of histamine was completely
blocked by pyrilamine, an H1 receptor antagonist, and mimicked by the H1 receptor
agonist, 2-methylhistamine. Whereas the H2 receptor antagonist, cimetidine,
slightly inhibited the effect of histamine and the effect of the H2 receptor
agonist, 4-methylhistamine, was minute. These results show that histamine
augments UVB-induced IL-6 production by keratinocytes predominantly via the H1
receptor at the level of transcription. This suggests a contributory role for
histamine in the exacerbation of atopic dermatitis induced by sun exposure.
PMID- 9763306
TI - Histopathological assessment of localized proliferation in cases of Bowen's
disease using immunostaining and a laser cytometer.
AB - In order to evaluate the localized proliferative activity of intratumor cells in
Bowen's disease using tissue sections, skin specimens from ten patients were
compared with skin samples from seven normal individuals for their expression of
proliferating cell nuclear antigen (PCNA), Ki-67 immunostaining and intranuclear
DNA contents, quantitated with a laser cytometer (LCM). In normal epidermis, the
largest proportion of PCNA- and Ki-67-positive cells was observed in the basal
cell layer, with the amounts decreasing through the suprabasal cell layer towards
the prickle cell layer. Examination by LCM also revealed the highest average
fluorescence intensity of individual nuclei in the basal cell layer and, as with
the immunohistological parameters, reducing towards the upper layer of the
epidermis. In the Bowen's disease tissue sections, the largest proportion of PCNA
and Ki-67-positive cells was found in contact with the basement membrane (base
of the tumor), with lower amounts in the center of the tumor nest and in the
marginal epidermis. The average fluorescence intensities of individual nuclei
were in line with these results. These results show that tumor cells distributed
in Bowen's disease tumor nests have different proliferative activities depending
on their location.
PMID- 9763307
TI - The genetic basis of "Scarsdale Gourmet Diet" variegate porphyria: a missense
mutation in the protoporphyrinogen oxidase gene.
AB - The porphyrias are disorders of porphyrin or porphyrin-precursor metabolism that
result from inherited or acquired aberrations in the control of the porphyrin
heme biosynthetic pathway. Variegate porphyria (VP), one of the acute hepatic
porphyrias, is characterized by a partial reduction in the activity of
protoporphyrinogen oxidase (PPO), and recently, mutations in the PPO gene on
chromosome 1q22-23 have been described. Our purpose was to identify the
underlying genetic lesion in a severely affected patient with VP and to detect
the silent mutation carriers in her family. The disease in this patient was
precipitated by carbohydrate restriction as outlined in the "Scarsdale Gourmet
Diet". Our mutation detection and confirmation strategy included PCR, automated
sequencing, and restriction enzyme digestion. We identified a missense mutation
in the patient and five family members. The mutation consisted of a previously
unreported C-to-T transition in exon 5 of the PPO gene, resulting in the
substitution of arginine by cysteine, designated R152C. This arginine residue is
evolutionarily highly conserved in humans, mice, bacteria, yeast, and plants,
indicating the importance of this residue in PPO. Our study established that a
missense mutation in the PPO gene was the underlying mutation in this patient
with VP and explained the occurrence of the phenotype in this family.
PMID- 9763308
TI - A study on Epstein-Barr virus in erythema multiforme.
PMID- 9763309
TI - Influence of topical tretinoin on skin lipid production in vivo.
PMID- 9763310
TI - The glycoprotein of the carcinoembryonic antigen (CEA) gene family expressed on
epithelial keratinocytes in viral warts.
PMID- 9763311
TI - Expression of melanoma-associated antigens in short-term melanoma cultures
detected by RT-PCR and subsequent ELISA.
PMID- 9763312
TI - Morphological and genetic characterisation of Cryptosporidium oocysts from
domestic cats.
AB - Faecal samples were collected from domestic cats in the metropolitan area of the
city of Perth, Western Australia, and screened for the presence of
Cryptosporidium by both microscopy and PCR. Of 162 samples screened, two were
positive for Cryptosporidium (a prevalence of 1.2%). Sample Ct33 was from an 18
month-old female and sample Ct131 from a 12-month-old female. Morphological
studies revealed oocysts with an average size of 4.6 x 4.0 microm, smaller in
size than isolates typically seen in humans (5.0 x 4.5 microm). Sequence analysis
of PCR products showed sequences from cat isolates to be different to previously
sequenced human and calf isolates, with cat isolates exhibiting 8.1% sequence
divergence from these isolates. Phylogenetic analysis grouped the cat isolates
into a distinct group, separate from other C. parvum isolates and Cryptosporidium
species. These results lend support to the existence of a cat-adapted
Cryptosporidium strain or species.
PMID- 9763313
TI - Comparison of three ELISA tests for seroepidemiology of bovine fascioliosis.
AB - The aim of the present study was to compare the sensitivity, specificity and
usefulness of the DIG-ELISA, DOT-ELISA and Indirect ELISA tests for determining
the seroprevalence of fasciolosis in cattle under tropical conditions in Mexico.
To standardize the tests, positive and negative sera to F. hepatica from 88
Holstein Freisian adult cows located in an enzootic area of fascioliosis and 88
crossbred adult cattle from a fluke-free area were used. For the epidemiological
study, 85 crossbred cattle between 1 to 7 years of age were used. Animals were
bled every two months, from March 1995 to September 1996 and the sera obtained
were stored at -70 degrees C, until used. Indirect ELISA showed a sensitivity of
96.5% and a specificity of 98.8%, DIG-ELISA 97.5% and 80.0% and DOT-ELISA 93.1%
and 95.4%, respectively. During 1995, Indirect ELISA yielded the highest levels
of IgG anti-F. hepatica antibodies. However, in 1996, after animal treatment with
triclabendazole, DIG-ELISA tended to show higher percentages of antibody-positive
animals, but it was not significantly different (p>0.05) from the other tests.
Comparisons made in parallel to the faecal sedimentation test demonstrated that
all serological tests detected higher percentages of positive animals. Only one
serum out of ten (10%) of Paramphistomum spp. cross-reacted with the DOT-ELISA
test, but no cross-reaction was observed with sera from animals with other
parasites. All ELISA tests were highly sensitive and specific; they may be
recommended for use in seroepidemiological surveys for F. hepatica.
PMID- 9763314
TI - Coproantigens: early detection and suitability of an immunodiagnostic method for
echinococcosis in dogs.
AB - In the present study immunodiagnostic tests for Echinococcus granulosus-specific
coproantigens have been evaluated. The techniques are based on polyclonal
antisera collected from dogs experimentally infected with E. granulosus
protoscoleces. ELISA, Countercurrent immunoelectrophoresis (CCIEP) and Immunodot
were evaluated for their application in coprodiagnosis. The level of
coproantigens was detectable on day 7 post-infection and reached a maximum level
on day 56 as detected by ELISA. Very high O.D values were obtained when faecal
samples of 7-8 weeks post-infection were used. Besides this, immunodot and CCIEP
were also tested and the 4th week post-infection samples gave significant
reactions. It is evident from the results that ELISA was more sensitive and
detected the coproantigens as early as the first week post-infection whereas
immunodot and CCIEP detected coproantigens later. The latter methods are rapid,
cost-effective and can be used to diagnose suspect cases of echinococcosis under
field conditions. Thus, it is suggested that future studies should be aimed at
early detection of echinococcosis by a rapid and cost-effective immunodot test.
PMID- 9763315
TI - Identification and semi-quantitation of Ostertagia ostertagi eggs by enzymatic
amplification of ITS-1 sequences.
AB - A region within the first internal transcribed spacer (ITS-1) of the ribosomal
DNA repeat of Ostertagia ostertagi has been identified that is 408 base pairs
(bp) in length and is comprised of a 2 x 204 bp repeat. Universal polymerase
chain reaction (PCR) primers which span this region, as well as a portion of the
5.8S rDNA, generate a 1011 bp fragment using genomic DNA from O. ostertagi.
However, these same primers generate only a 600 bp (approximate) fragment using
DNA from Haemonchus contortus, Cooperia oncophora and Oesophagostomum radiatum,
as well as other species within the genus Ostertagia. When DNA samples derived
from adult parasites of the different genera were mixed and simultaneously
amplified, the O. ostertagi component could be identified within the mixed DNA
populations. Furthermore, a correlation was observed between relative
fluorescence intensities of the 1011 bp and the 600 bp PCR fragments and the
percentage of O. ostertagi DNA within a mixture of parasite DNAs. A similar high
correlation was obtained between the percentage of O. ostertagi DNA and percent
O. ostertagi eggs in feces containing eggs of other nematode genera. This
resulted in the generation of a protocol that can determine the percentage of O.
ostertagi eggs within a mixed population of gastrointestinal nematode eggs.
Results indicate a detection equivalent to 0.05 eggs.
PMID- 9763316
TI - Field efficacy of doramectin pour-on against naturally-acquired, gastrointestinal
nematodes of cattle in North America.
AB - Seven studies were conducted under field conditions in North America to evaluate
the therapeutic efficacy of doramectin in a pour-on formulation at a dosage of
500 microg/kg (1 ml/10 kg) for cattle harboring naturally-acquired infections of
gastrointestinal nematodes, including species of Haemonchus, Ostertagia,
Trichostrongylus, Bunostomum, Cooperia, and Oesophagostomum. In each study, 40 to
100 cattle were randomly allocated to a saline- or doramectin-treated group in a
tiered manner based on Day -7 bodyweight. On Day 0, the cattle received either
saline or doramectin topically, according to their treatment group. Weather and
safety observations were made following treatment. No adverse reaction to
treatment was observed at any time during these studies. Fecal egg count (FEC)
determinations were carried out on each animal on Days -7, 0, 7, 14, and 21.
Reductions in FEC for the doramectin-treated animals compared to saline-treated
cattle were > or = 96.0% by Day -7 and > or = 99.0% on Days 14 and 21 for each
study. Across all studies regardless of weather conditions, the reduction by Day
21 for the doramectin-treated animals compared to saline controls was 99.7% (p <
or = 0.0001) and compared to pretreatment levels in doramectin-treated cattle was
99.9% (p < or = 0.0001). Doramectin pour-on should provide a useful new treatment
for controlling nematode parasites of cattle.
PMID- 9763317
TI - Canine filariasis. Importance and transmission in the Baix Llobregat area,
Barcelona (Spain).
AB - Field and laboratory studies were performed in order to assess the degree of
canine dirofilariasis caused by Dirofilaria immitis (Leidy) in the Baix Llobregat
region, a fluvial area near Barcelona, Spain. A total of 188 dogs were sampled
between May and August of 1994. Three main areas were chosen: the Western Delta,
the Eastern Delta and the Northern zone. Simultaneously, a mosquito sampling
programme was carried out with CO2 light traps, to search for infective larvae
(L3) of D. immitis. Of the 188 dogs sampled, 38 were positive for at least one of
the three filaria found: D. immitis 12.8%, Dipetalonema reconditum (Grassi) 3.7%
and Dipetalonema dracunculoides (Cobbold) 2.7%. Only 1.1% showed a mixed
infection of both D. immitis and D. dracunculoides. Although Dirofilaria repens
Raillet et Henry has been found in Spain, it was not found in this study.
Comparing the three zones of the Baix Llobregat, the Eastern Delta showed the
highest level of D. immitis (35.3%), probably due to the presence of Aedes
caspius (Pallas). Despite the effort in sampling the mosquito population, D.
immitis was not found in any of the 2001 females dissected, belonging to 5
species.
PMID- 9763319
TI - Course of the endogenous developmental phase of selected Eimeria species in
pheasants.
AB - The localization and duration of developmental stages of Eimeria colchici and
Eimeria duodenalis were studied histologically. The prepatent period of the most
pathogenic species from the caeca of pheasants--Eimeria colchici--was 6 days. The
patent period began on the 7th day and finished on the 11th day post-infection
with the maximum production of oocysts on days 8-9. In the case of Eimeria
duodenalis the prepatent period was shorter--4 days, and the duration of the
patent period was 3-4 days without a significant increase in oocyst production.
PMID- 9763318
TI - Use of a mathematical model to study the control measures of the cattle tick
Boophilus microplus population in New Caledonia.
AB - Boophilus microplus is a common cattle tick of great economic importance in
various tropical and subtropical countries like New Caledonia. The proposed model
describes the population dynamics of female Boophilus microplus in the absence of
resistant ticks. It is a system of six difference equations which can be
mathematically analyzed. The analysis of the system shows the great importance of
the eigenvalue denoted by lambda1. The population of ticks increases if lambda1 <
1 and decreases if lambda1 > 1. The lambda1 eigenvalue depends, in particular, on
the parasitic surviving rate and encounter rate between the larvae and the cows.
The treatments decrease the parasitic surviving rate as the agronomic measures
decrease the encounter rate. This model permits to quantify the conditions of
treatments (or of the efficacy of a vaccine) and of agronomic measures by which
the populations are controlled. It shows that the different treatment rhythms and
the presence or not of the wild or domestic refuges plays a major role on the
dynamics of tick population.
PMID- 9763320
TI - Neosporosis in a dog in Italy.
AB - Clinical neosporosis was diagnosed in a 2-month-old Pit Bull Terrier from Italy.
Neospora caninum tachyzoites were found in semitendinosus muscle with myositis.
The diagnosis was confirmed by immunohistochemical staining with anti-N. caninum
specific antibodies. This is the first report of systemic neosporosis in dogs
from Italy.
PMID- 9763321
TI - Limited role of lagomorphs (Oryctolagus cuniculus and Lepus capensis) in the
dispersion of parasite nematodes of ruminants.
AB - Rabbits (Oryctolagus cuniculus) and hares (Lepus capensis) were investigated
under natural conditions for infection with ruminant nematodes, either in the
condition of close contact with sheep (south-east of France) or unknown contact
with ruminants (central region and French Champaign). Rabbits and hares were
poorly infected with sheep digestive tract nematodes: Trichostrongylus
colubriformis (second record) was encountered in one site and Trichostrongylus
capricola (a first record) in another site, at very low intensity. Small sheep
lungworms (Neostrongylus linearis and Cystocaulus ocreatus) were not recorded in
rabbits grazing common pasture with sheep. Although transmission remained limited
between lagomorphs and ruminants, it could play a role in the transfer of
nematode isolates resistant to anthelmintics from one farm to another.
PMID- 9763322
TI - Experimental infection of inbred mouse strains with Spironucleus muris.
AB - Four inbred mouse strains: BALB/c ByJ, 129/J, C3H/HeJ, and DBA/lJ, differing in
major histocompatibility type, were orally inoculated with 2 x 10(5) infectious
cysts of Spironucleus muris. Fecal samples were collected for fecal cyst output
prior to infection, and on days 2, 6, 7, 8, 9, 11, 13, 15, and 17 after
infection. Following necropsy, formalin-fixed intestinal sections were examined
for the presence of trophozoites. On post-inoculation days 6 and 8, mice of the
129/J strain shed significantly (p<0.05) fewer cysts than other strains. This
pilot study suggests that major histocompatibility haplotype may influence
susceptibility of inbred mouse strains to S. muris.
PMID- 9763323
TI - Evaluation of 2 methods to assess gingival bleeding in smokers and non-smokers in
natural and experimental gingivitis.
AB - The purpose of the present study was to compare the bleeding tendency as elicited
by probing the marginal gingiva (BOMP) and probing to the bottom of the pocket
(BOPP) in smokers and non-smokers in natural gingivitis and during experimental
gingivitis. 11 smokers (sm) and 14 non-smokers (nsm) were recruited. When they
had less than 20% approximal bleeding sites, they entered a 14-day trial period
of 'experimental gingivitis'. Subjects returned 30 days later, after resuming
normal oral hygiene procedures, for a final gingival assessment. A split-mouth
design was chosen using 2 contra-lateral quadrants for each index (being either
BOMP or BOPP). A consistently higher bleeding score of approximately 10% was
observed by probing to the bottom of the pocket. At day 14 with both indices, a
significant difference between smokers and non-smokers was detected (BOMP:
sm=15%, nsm=30%; BOPP: sm=27%, nsm=44%). The increment between gingival health
and experimental gingivitis was significantly higher in non-smokers than in
smokers but comparable for both indices (BOMP: sm=8%, nsm=23%; BOPP: sm=9%,
nsm=26%). Probing to the bottom of the pocket results in significantly more
bleeding in gingival health and gingivitis as compared to probing of the marginal
gingiva. This shows that evaluation of the gingival condition with BOMP, the
method of choice with respect to gingivitis, can be used as a parameter for
inflammation when comparing smokers and non-smokers. The suppressed inflammatory
response to plaque accumulation, as observed in smokers, indicates that they
should be identified as a separate group when they participate as panelists in
(experimentally induced) gingivitis studies.
PMID- 9763324
TI - Evaluation of the incidence of gingival abrasion as a result of toothbrushing.
AB - The aims of the present study were: (1) to establish the incidence of gingival
abrasion as a result of toothbrushing, using a manual and electric toothbrush;
(2) to establish the influence of filament end-rounding on the incidence of
gingival abrasion and the efficacy of toothbrushing; (3) to assess whether the
speed of the electric brush has a feedback-effect on the brushing force used and
to correlate the incidence of gingival abrasion with force. 2 experiments were
carried out. In the first experiment, 50 subjects brushed for 3 weeks every other
day with either a manual (Butler 411) or an electric toothbrush (Braun/Oral-B
Ultra Plaque Remover-D9). All received brief instructions and were asked to
abstain from oral hygiene 24 hrs before their appointment. After disclosing the
teeth and gums with Mira-2-Tone solution, plaque and gingival abrasion were
assessed. Next, the panelists brushed in a random split-mouth order. After
brushing and a second disclosing, plaque and abrasion were re-assessed. The
results showed that the incidence of gingival abrasion was comparable for the
manual and the D9. Using a similar design as in experiment no. 1, in experiment
no. 2 a new group of 47 subjects brushed for 3 weeks alternating between the
Braun/Oral-B Plaque Remover-D7 and D9. At the appointment, the subjects first
brushed in a split-mouth order with the D9 with 2 different types of endrounding.
Plaque and abrasion were assessed. Immediately following this brushing exercise,
the subjects re-brushed with the D7 (2800 rot/min) and the D9 (3600 rot/min)
during which brushing force was measured. The results of this experiment showed
that endrounding has no effect on plaque removal but does effect the incidence of
gingival abrasion. Brushing force is not influenced by the speed of the brushhead
and no correlation with the incidence of gingival abrasion was observed. In
conclusion, the results of this study show that gingival abrasion is not
influenced by brushing force, but is affected by filament endrounding.
PMID- 9763325
TI - Root conditioning using EDTA gel as an adjunct to surgical therapy for the
treatment of intraosseous periodontal defects.
AB - The aim of this clinical study was to compare the treatment outcome following
root surface conditioning using an EDTA gel preparation in conjunction with
surgical therapy with that following conventional flap surgery in periodontal
intraosseous defects. 36 patients, each of them contributing one intraosseous
defect > or =4 mm in depth participated. Defect sites had a probing pocket depth
> or =5 mm and bled on probing following hygienic treatment phase. No furcation
involvement or endodontic complications were present. In the EDTA group, 18
consecutive patients, defects were treated by root conditioning with EDTA gel for
3 minutes in combination with surgical therapy. In the control group, 18
patients, conventional flap surgery was performed without root conditioning.
Chlorhexidine rinsings 0.2% were prescribed following surgery for 2-3 weeks with
modified oral hygiene instruction. A strict recall program was implemented
including professional prophylaxis and oral hygiene reinforcement every 4-6 weeks
until 6-month re-evaluation. Baseline probing pocket depths and defect depths of
7.1+/-1.3 mm and 6.9+/-1.6 mm in the EDTA group and 7.6+/-1.9 mm and 6.6+/-1.7
mm, respectively, in the control group were measured. 6-month clinical results
showed a significant probing attachment level gain of 1.8+/-1.5 mm and 1.0+/-1.7
mm in the EDTA and control groups respectively. A probing bone gain of 1.0+/-1.3
mm in the EDTA group was measured with a non-significant gain of 0.4+/-1.2 mm in
the control group. Radiographic analysis confirmed these results. There were no
statistically significant differences in treatment outcome between the group
treated by root conditioning in combination with flap surgery and conventional
flap surgery alone.
PMID- 9763326
TI - Low stimulation of peripheral lymphocytes, following in vitro application of
Emdogain.
AB - Fast tissue regeneration after therapeutic manipulations is a central problem of
periodontology, oral surgery and trauma of the periodontal tissues, including
bone. Several products, which augment tissue regeneration, have been manufactured
and assayed in clinical practice with positive results. Emdogain is a recent
addition in this field, as a tissue-regenerating product. The substance is a
derivative of amelogenin, obtained from porcine embryonic tissues. At the present
time, it is not known whether the substance can induce a local (due to the uptake
of the substance) or systemic immune response. The aim of the present study was
to evaluate, in vitro, the ability of Emdogain to influence, in vitro, the immune
system. Peripheral blood lymphocytes, isolated for 10 healthy donors, were
cultured in the presence of various concentrations of the substance, in order to
determine the rate of cell proliferation, the expression of surface antigens and
the production of cytokines and immunoglobulins. Under our experimental
conditions, Emdogain produced a slight increase of the proliferation of
lymphocytes, restricted to the CD25 (IL-2 receptor) fraction of the CD4 positive
T-lymphocytes, and a concomitant decrease of CD19 positive B-lymphocytes. Other
cell fractions (CD8 positive T-cells, B-cells and NK-cells) were not affected.
Under our conditions too, immunoglobulin and cytokin (IL-2 and IL-6) production
was not modified, even after a 3-day application of concentrations much higher
than those used in clinical practice. Our data suggest that Emdogain slightly
induce an immune response, restricted to the activated fraction of CD4 T
lymphocytes in vitro.
PMID- 9763327
TI - The mucosal attachment at different abutments. An experimental study in dogs.
AB - The present experiment was performed to examine if the material used in the
abutment part of an implant system influenced the quality of the mucosal barrier
that formed following implant installation. 5 beagle dogs were included in the
study. The mandibular premolars and the 1st, 2nd and 3rd maxillary premolars were
extracted. Three fixtures of the Branemark System were installed in each
mandibular quadrant (a total of 6 fixtures per animal). Abutment connection was
performed after 3 months of healing. In each dog the following types of abutments
were used: 2 "control abutments" (c.p. titanium), 2 "ceramic abutments" (highly
sintered Al2O3), 1 "gold abutment", and 1 "short titanium abutment". This "short
titanium abutment" was provided with an outer structure made of dental porcelain
fused to gold. Following abutment connection a plaque control program was
initiated and maintained for 6 months. The animals were sacrificed and perfused
with a fixative. The mandibles were removed and each implant region was
dissected, demineralized in EDTA and embedded in EPON. Semithin sections
representing the mesial, distal, buccal and lingual aspects of the peri-implant
tissues were produced and subjected to histological examination. The findings
from the analysis demonstrated that the material used in the abutment portion of
the implant influenced the location and the quality of the attachment that
occurred between the periimplant mucosa and the implant. Abutments made of c.p.
titanium or ceramic allowed the formation of a mucosal attachment which included
one epithelial and one connective tissue portion that were about 2 mm and 1-1.5
mm high, respectively. At sites where abutments made of gold alloy or dental
porcelain were used, no proper attachment formed at the abutment level, but the
soft tissue margin receded and bone resorption occurred. The abutment fixture
junction was hereby occasionally exposed and the mucosal barrier became
established to the fixture portion of the implant. It was suggested that the
observed differences were the result of varying adhesive properties of the
materials studied or by variations in their resistance to corrosion.
PMID- 9763328
TI - A controlled multicenter study of adjunctive use of tetracycline periodontal
fibers in mandibular class II furcations with persistent bleeding.
AB - The aim of this randomized single-blind multicenter controlled clinical trial was
to clinically evaluate the effectiveness of adjunctive local controlled drug
delivery in the control of bleeding on probing in mandibular class II furcations
during maintenance care. 127 patients presenting with a class II mandibular
furcation with bleeding on probing were included in the study. They had been
previously treated for periodontitis and were participating in supportive care
programs in periodontal specialty practices. Treatments consisted of scaling and
root planing with oral hygiene instructions (control) and scaling and root
planing and oral hygiene combined with local controlled drug delivery with
tetracycline fibers (test). The following outcomes were evaluated at baseline and
3 and 6 months after therapy at the furcation site: bleeding on controlled force
probing (BOP), probing pocket depth (PD) and clinical attachment levels (CAL).
Levels of oral hygiene and smoking status were also assessed. Both test and
controls resulted in significant improvements of BOP and PD at 3 and 6 months.
The test treatment, however, resulted in significantly better improvements: BOP
decreased by 52% in the control group and by 70% in the test group at 3 months;
at 6 months, however, the difference was no longer significant. The test
treatment resulted in a 0.5 mm greater reduction of PD than the control at 3
months, the improvement was highly significant but its duration did not extend
until the 6 months evaluation. No differences were observed in terms of changes
in CAL. These data indicate that addition of tetracycline fibers to mechanical
therapy alone resulted in improved control of periodontal parameters during
periodontal maintenance of class II mandibular furcations. Short duration of the
effect, however, requires further investigations to optimize conservative
treatment of these challenging defects.
PMID- 9763329
TI - Evaluation of tetracycline fiber therapy with digital image analysis.
AB - The aims of the present study were to assess radiographically the effects of
scaling/root planing combined with antibiotic therapy using tetracycline fibers
(TCF): (I) on alveolar bone density and linear descriptors and (II) on
supracrestal soft tissue density. 19 subjects with generalized adult
periodontitis (with at least 20 teeth present, at least 4 teeth with pockets >4
mm and bleeding upon controlled force probing) and high cultural counts of
Porphyromonas gingivalis were recruited from a pool of 57 patients. The full
mouth treatment group (FT) consisted of 10 patients, who underwent a full mouth
supra-gingival scaling and prophylaxis treatment and were instructed to rinse 2x
daily with a 0.1% chlorhexidine solution. 1 week later, tetracycline
hydrochloride-containing fibers (Actisite periodontal fiber) were applied around
all teeth. After 7-12 days, the fibers were removed and all teeth were scaled and
root planed under local anaesthesia. The chlorhexidine rinsing continued for
another 2 months. In 9 subjects (local treatment group LT), 2 teeth with
periodontal lesions with pocket probing pepth (PPD) > or =5 mm were treated by
placement of tetracycline fibers, which remained in place for 7 to 12 days. Upon
removal of the fibers, scaling and root planing was performed on these 2 teeth,
while the rest of the dentition remained untreated, and no chlorhexidine rinse
was applied. 2 of the untreated teeth revealing similar periodontal lesions were
chosen to represent sites affected by untreated periodontitis (NT). In this
group, a limited local treatment was performed (2 teeth) with the inherent
potential for recolonization from the untreated pocket sites. Standardized
periapical radiographs were obtained from the 4 monitored sites within each
patient at baseline (before treatment) and 2 and 6 months thereafter. One
radiograph was exposed in a standard way for bone assessment. The second
radiograph was underexposed, at about a 1/5 of the original exposure time to
allow the evaluation of soft tissue. Mean changes in the linear parameters and
changes in density (CADIA) observed at multiple sites within each patient and
treatment group were used as the best estimate of treatment outcome. Over the
observation period of 6 months, a significant difference in bone height changes
was found between the untreated sites (median loss -0.29 mm) and the sites from
full-mouth treated patients (median gain 0.24 mm, p=0.008). When comparing the
baseline to the 6 months radiographs, a loss in bone density was observed for the
untreated group (median=-2.13 CADIA). Both treatment groups revealed a gain in
density (median=1.58 and 2.43 CADIA for the locally and the full-mouth treated
groups, respectively). Differences in density were significant, both between the
nontreated and locally treated sites (p=0.026) and between the nontreated sites
and the sites from the full mouth treated patients (p=0.002). The analysis of the
soft tissues showed a similar pattern of changes in density to those seen in the
bone defect. At 2 months, there was a tendency for loss in density for the
nontreated group (median=-0.17 CADIA) that continued over the 6 month period
(median=-0.31 CADIA). A significant increase in density was observed for the full
mouth treated sites (median=1.57 and 0.64 CADIA for the 2 and 6 months
radiographs, respectively). A significant increase was also observed for the
locally treated group when compared to the untreated sites (median=0.13 and 0.10
CADIA for the 2 and 6 months radiographs, respectively). Comparing untreated
sites with full-mouth treated sites, a significant difference was observed for
CADIA measurements (p<0.001). No significant difference was observed comparing
locally treated and untreated sites (p=0.24). It was concluded that scaling and
root planing combined with TCF therapy can result in increased bone density and
alveolar bone height. Full-mouth treatment seemed to result in more pronounced
gains compared to local tre
PMID- 9763331
TI - High levels of soluble intercellular adhesion molecule-1 (ICAM-1) in crevicular
fluid of periodontitis patients with plaque.
AB - The intercellular adhesion molecule-1 (ICAM-1) is a membrane-bound molecule
involved in cell-cell adhesive interactions which is upregulated on inflammatory
epithelial cells. The levels of soluble ICAM-1 (sICAM-1) shed into the gingival
crevicular fluid (GCF) were studied in healthy patients and patients with
gingivitis, adult periodontitis or rapidly progressive periodontitis, using an
ELISA technique. Clinical parameters including plaque index, gingival index,
probing depth, and bleeding on probing were recorded following careful sampling
of GCF with standardised filter strips. In GCF, sICAM-1 levels were higher for
patients with plaque (p=0.04) and for patients with inflammation (p=0.02), but
did not correlate with disease classifications. These results suggest that
elevated GCF sICAM-1 levels may represent increased shedding of this molecule in
the interstitial fluid as a result of membrane-bound ICAM-1 upregulation on ICAM
1 gingival-bearing cells in relation with plaque accumulation and inflammation.
PMID- 9763330
TI - 6-month use of 0.2% delmopinol hydrochloride in comparison with 0.2%
chlorhexidine digluconate and placebo. (I). Effect on plaque formation and
gingivitis.
AB - A double-blind, randomised, 6-month clinical trial with parallel group design in
149 patients with gingivitis was conducted to study the efficacy and safety of
delmopinol hydrochloride 2 mg/ml (0.2% w/v, Decapinol Mouthwash) used for partly
supervised mouthrinsing in comparison with chlorhexidine digluconate 2 mg/ml
(0.2% w/v, Hibitane Dental, ICI Pharmaceuticals, UK) and placebo as an addition
to normal oral hygiene. Assessments of efficacy were performed using the plaque
index and bleeding on probing (BOP). Delmopinol showed 22% lower plaque index
scores than placebo after 3 months (p<0.01) and 13% lower scores after 6 months.
The corresponding figures for chlorhexidine were 38% (p<0.001) and 38% (p<0.001)
after 3 and 6 months, respectively. Bleeding on probing was reduced for
delmopinol in comparison with placebo by 11% after 3 months and by 18% (p<0.05)
after 6 months. For chlorhexidine the corresponding figures were 18% (p<0.01) and
22% (p<0.01) after 3 and 6 months, respectively. While chlorhexidine showed
greater plaque reduction than delmopinol (p<0.01 at 6 months), no statistically
significant difference was reached between these two solutions regarding BOP.
Both active solutions showed an increased amount of dental calculus in comparison
with placebo. A transient anaesthetic sensation in the oral mucosa and taste
affection were commonly reported adverse events in both the delmopinol and the
chlorhexidine groups. The number of patients withdrawn from treatment due to
adverse events or lack of cooperation was 7 in the chlorhexidine group, 4 in the
placebo group and 1 in the delmopinol group. The results showed that rinsing with
either 0.2% delmopinol hydrochloride or 0.2% chlorhexidine digluconate twice
daily for 60 secs for 6 months results in less plaque formation and gingivitis
than rinsing with placebo. Mouthrinsing with the 0.2% delmopinol hydrochloride
solution was well accepted in this study.
PMID- 9763332
TI - Subgingival microflora and treatment in prepubertal periodontitis associated with
chronic idiopathic neutropenia.
AB - Prepubertal periodontitis affects both primary and permanent dentition. The
purpose of this study was to examine the composition of subgingival microflora of
the permanent dentition in an 11-year-old Caucasian female, who had premature
exfoliation of her deciduous teeth on her 5th year of age, and the response of
this condition to the antibiotic therapy and supportive periodontal care.
Gingival tissues were highly inflamed and alveolar bone loss was detected
radiographically. The girl had experienced frequent upper respiratory tract
infections, tonsilitis and recurrent otitis media. Her mother had history of
early onset periodontitis associated with chronic idiopathic neutropenia. Blood
chemistry tests and immunological examinations were also performed. Subgingival
plaque samples were collected from the proximal sites of permanent molars,
incisors, canines and maxillary premolars. 27 different microbial species were
isolated from the subgingival microflora. Among the predominant species were
Porphyromonas gingivalis (17.6%-7.3%), Prevotella intermedia (12.4%-4.7%),
Capnocytophaga sputigena (14.4%-10.4%), Capnocytophaga ochracea (13.2%-6.9%) and
Actinobacillus actinomycetemcomitans (9.3%-5.5%). Periodontal treatment consisted
of scaling, root planing in conjunction with antibiotic administration of
Augmentin 312.5 mg and Flagyl 200 mg, each t.i.d. for 10 days. 3 weeks after the
antibiotic therapy, bacterial samples were collected from the same sites. All the
periodontal pathogens were recovered in lower levels and A.actinomycetemcomitans
was almost eliminated in the 3-week period. The evaluation of clinical indices at
3, 6 and 12 months showed that periodontal treatment in conjunction with
antibiotics was effective and rapidly followed by marked clinical improvement.
The microbiological monitoring at 3, 6 and 12 months after antibiotic treatment
and each time prior to supportive periodontal care, revealed that the periodontal
pathogens fluctuated in low levels even 12 months after treatment and could be
maintained at low level by supportive periodontal care at 3-month intervals.
PMID- 9763333
TI - MRI anatomy of white matter layers around the trigone of the lateral ventricle.
AB - MRI was obtained in eight normal volunteers and seven patients with brain oedema
around the trigone. In addition to the conventional sequences, diffusion-weighted
and intravoxel-incoherent-motion images using motion-proving anteroposterior
and/or lateral direction gradients were obtained to show the white matter
pathways better. Coronal proton-density-weighted images showed three thin
relatively high-intensity layers in addition to the tapetum and the internal and
external sagittal strata. Although they have not been confirmed anatomically, the
thin layer between the internal and the external sagittal strata was corroborated
by diffusion-weighted and intravoxel-incoherent-motion images, and by
characteristics of the spread of oedema into the sagittal stratum. We propose
that this layer be named the central sagittal lamina. The other two layers medial
and lateral to the sagittal stratum were outside, but in contact with the medial
and lateral parts of the sagittal stratum, respectively. We provisionally named
them medial and lateral sagittal laminae; they were not evident on any other
images. The low-intensity layer on T2-weighting was the internal sagittal
stratum. The optic radiation, comprising the external sagittal stratum, appeared
as an intermediate to slightly high-intensity layer on T2-weighted images and a
low-intensity layer on T1-weighted images as did the corticospinal tract in the
posterior internal capsule.
PMID- 9763334
TI - Fast fluid-attenuated inversion-recovery imaging: first experience with a 3D
version in epilepsy.
AB - We developed a 3D version of fast fluid-attenuated inversion-recovery imaging
(FLAIR) which provides images with a slice thickness of 1.5 mm. We present our
initial experience with 3D fast FLAIR in patients with epilepsy. We compared 3D
fast FLAIR (slice thickness 1.5 mm), 2D fast FLAIR (slice thickness 5 mm) and a
3D spoiled GRASS (IRSPGR) sequence (slice thickness 1.5 mm) in 10 patients with
lesional epilepsy (head injury 1, hippocampal sclerosis 2, low-grade glioma 2,
dysembryoplastic neuroepithelial tumour 2, polymicrogyria 1, perinatal infarct 1
and presumed thrombosed aneurysm 1). Both 2D and 3D fast FLAIR sequences yielded
higher conspicuity for lesions than the T1-weighted IRSPGR sequence, except in
the patient with polymicrogyria. The extent of the lesion, in particular that of
low-grade tumours, was best assessed on 3D fast FLAIR images. 3D fast FLAIR may
be a useful additional tool especially for imaging low-grade tumours.
PMID- 9763335
TI - Transcranial duplex sonography of middle cerebral artery stenosis: a comparison
of colour-coding techniques--frequency- or power-based Doppler and contrast
enhancement.
AB - The main limitation of transcranial colour-coded duplex sonography (TCCD) is the
inadequate acoustic window, which prevents transtemporal identification of the
basal cerebral arteries in up to 30% of cases, especially in the elderly. TCCD
with different colour-coding techniques, including frequency-based colour-flow
(CFD) or power (PD) Doppler sonography, used alone or in combination with
contrast media, were used in 23 patients with middle cerebral artery (MCA)
stenosis. In 10 patients a contrast medium (400 mg/ml SHU 508 A) was administered
because of inadequate colour-coded visualisation with TCCD. The data were
compared with angiographic methods. Digital subtraction angiography (DSA)
revealed 2 low-grade, 11 middle-grade and 10 high-grade stenoses in the M1
segment. With TCCD, we found a 7.7% higher blood flow velocity (systolic peak
velocity) than with transcranial duplex sonography without colour-coding because
of visual angle correction and a 20% higher systolic peak velocity using contrast
enhancement. CFD did not differ from PD in identification of low- and middle
grade MCA stenoses, but PD alone revealed two more cases of high-grade stenosis
than CFD. The contrast medium increased diagnostic confidence in 8 of 10 cases.
Only 2 of 23 MCA stenoses (9%) could not be shown using TCCD.
PMID- 9763337
TI - Assessment of T2- and T1-weighted MRI brain lesion load in patients with
subcortical vascular encephalopathy.
AB - Previous cross-sectional studies in patients with subcortical vascular
encephalopathy (SVE) have shown little or no correlation between brain lesion
load and clinical disability, which could be due to the low specificity of T2
weighted MRI. Recent studies have indicated that T1-weighted MRI may be more
specific than T2-weighted MRI for severe tissue destruction. We studied 37
patients with a diagnosis of SVE and 11 normal controls with standardised T1- and
T2-weighted MRI. All patients underwent detailed clinical assessment including a
neuropsychological test battery and computerised gait analysis. Both the T2- and
T1-weighted total MRI lesion loads different between patients and controls
different, particularly T1. The ratio of T2-/T1-weighted lesion load was lower in
controls than in patients. There was no overall correlation of T1- or T2-weighted
lesion load with clinical disability, but group comparison of patients with
severe and mild clinical deficits showed different lesion loads. We suggest that
T1- and T2-weighted MRI lesion loads demonstrate relevant structural abnormality
in patients with SVE.
PMID- 9763336
TI - MRI assessment of cerebral blood volume in patients with brain infarcts.
AB - MRI perfusion studies have focussed mainly on acute ischaemia and
characterisation in ischaemia. Our purpose was to analyse regional brain
haemodynamic information in acute, subacute, and chronic ischaemia. We performed
16 examinations of 11 patients on a 1.5 T MR images. Conventional and dynamic
contrast-enhanced imaging were employed in all examinations. For the dynamic
susceptibility sequences, a bolus (0.2 mmol/kg) of gadopentetate dimeglumine was
injected. Reconstructed regional relative cerebral blood volume (rCBV) maps,
bolus maps, and conventional images were analysed by consensus reading. In all
examinations decreases in rCBV were observed in the lesions. The distribution of
regional rCBV in lesions was heterogeneous. The rCBV of the periphery of the
lesions was higher than that at their center. There was a correlation between the
time since onset and abnormalities on the rCBV map and T2-weighted images (T2WI).
In the early stage of acute stroke, the abnormalities tended to be larger on the
rCBV than on T2WI. Many patterns of bolus passage were observed in ischaemic
regions. rCBV maps provide additional haemodynamic information in patients with
brain infarcts.
PMID- 9763338
TI - MRI of germinomas arising from the basal ganglia and thalamus.
AB - We reviewed the MRI findings of germinomas originating from the basal ganglia,
thalamus or deep white matter in 13 patients with 14 germinomas, excluding those
in the suprasellar or pineal regions. Ten cases were confirmed as germinomas by
stereotaxic biopsy, three by partial and one by total removal of the tumour.
Analysis was focussed on the location and the signal characteristic of the
tumour, haemorrhage, cysts within the tumour and any other associated findings.
Thirteen of the tumours were in the basal ganglia and one in the thalamus.
Haemorrhage was observed in seven patients, while twelve showed multiple cysts.
Associated ipsilateral cerebral hemiatrophy was seen in three patients. The
signal intensity of the parenchymal germinomas was heterogeneous on T1- and T2
weighted images due to haemorrhage, cysts and solid portions. We also report the
MRI findings of germinomas in an early stage in two patients.
PMID- 9763339
TI - Meningeal involvement in Behcet's disease: MRI.
AB - Behcet's disease is a multisystem disease that involves the central nervous
system up to half of cases. Presentation with neurologic symptoms occurs in 5% of
cases and cerebral venous thrombosis is one of its major manifestations. A
feature not previously reported is progressive meningeal thickening with
involvement of both optic nerves. We report a patient with cerebral venous
thrombosis, meningeal thickening and contrast enhancement on MRI. This patient
had two other unusual features: positive antineutrophil cytoplasmic antibodies
and later development of central diabetes insipidus.
PMID- 9763340
TI - MRI in a patient with congenital agammaglobulinaemia.
AB - MRI in a 17-year-old boy with known congenital agammaglobulinaemia (CA)
demonstrated signs of chronic leptomeningeal inflammation with thickened,
enhancing meninges. Furthermore, high signal was found symmetrically on T2
weighted images in the frontal and parietal white matter. The patient presented
with severe general brain dysfunction and recent cerebellar ataxia. Extensive
investigation did not reveal a causal agent. This case shows that MRI can be
helpful in establishing the presence of pathological changes in cases where
laboratory results are negative.
PMID- 9763341
TI - MRI in chronic toluene abuse: low signal in the cerebral cortex on T2-weighted
images.
AB - MRI may be helpful in showing brain toxicity associated with chronic toluene
inhalation. We report clinical and MRI findings over 3 years in a man with
gradual neurologic decline secondary to toluene abuse. Cerebral atrophy most
prominently involved the corpus callosum and cerebellar vermis. On T2-weighted
images, loss of gray-white matter contrast, diffuse supratentorial white matter
high-signal lesions, and low signal in the basal ganglia and midbrain were seen.
In addition, MRI showed abnormal labor cortical low signal on T2-weighted images,
most prominent in the primary motor and visual cortex. This cortical T2
shortening, not previously described in this condition, may reflect iron
deposition.
PMID- 9763342
TI - Intraventricular B-cell lymphoma from the breast.
AB - We report an unusual case of massive intraventricular spread of B-cell lymphoma
of the breast, presenting with rapidly progressive ataxia and impaired cognition
with need for ventriculostomy. Rapid resolution followed intravenous
dexamethasone and radiation therapy.
PMID- 9763343
TI - Sacral haemangioma as a cause of coccydynia.
AB - We report a 55-year-old woman with coccydynia due to a sacral mass. The
histological diagnosis was haemangioma. The MRI findings and the unusual location
of this lesion are discussed.
PMID- 9763344
TI - Case report: glomus tumour of the nasal cavity and paranasal sinuses.
AB - Glomus tumours are relatively rare in the head and neck. We present a glomus
tumour of the nasal cavity and paranasal sinuses in a 55-year-old man and
describe the CT appearances of this tumour and its histopathology.
PMID- 9763345
TI - Effects of systemic heparinization on the thrombogenicity of hydrophilic and
nonhydrophilic catheters in a swine model.
AB - We assessed the effect of systemic heparinization on the in-vivo thrombogenicity
of various micro- and guiding catheters in a swine model. Microcatheters were
placed through 6-F guiding catheters into the common carotid arteries of swine
for 30-min (short-term) and 90-min (medium-term) periods, with and without
systemic heparinization. At the end of the placement period the microcatheters
were retracted through the guiding catheters and fixed for scanning electron
microscopy (SEM). Guiding catheters were harvested after 5 h placement, with and
without systemic heparinization, by retraction through 8-F sheaths and fixed for
SEM. The surfaces of both hydrophilic and nonhydrophilic microcatheters all
demonstrated more accumulation of debris during placement without than with
systemic heparinization. The difference was primarily in the amount of fibrillary
material on the catheter surface. The guiding catheters also demonstrated
increased debris accumulation without systemic heparinization. This suggests
that, even when using relatively nonthrombogenic catheters, systemic
heparinization is indicated during cerebral angiography.
PMID- 9763346
TI - Magnetic resonance angiography in patients with acute stroke treated by local
thrombolysis.
AB - Although magnetic resonance angiography (MRA) is accepted for showing chronic
intracranial stenotic or occlusive lesions, the method has not been practically
examined in patients with acute cerebral ischaemia. We carried out three
dimensional time-of-flight MRA in six patients with acute ischaemia treated by
local thrombolysis, and compared the findings with those of digital subtraction
angiography (DSA). In all patients, MRA before thrombolysis clearly demonstrated
the occluded arteries, which corresponded precisely to those shown by DSA. In
four patients with complete recanalisation of the occluded vessels after
thrombolysis, the recanalisation could be demonstrated by postoperative MRA. In
one patient with reocclusion of the recanalised artery, repeat MRA also
demonstrated the reocclusion, confirmed by DSA. These results suggest that MRA
may be helpful for noninvasive investigation before and after thrombolysis.
PMID- 9763347
TI - Neuroradiological practices in Europe: Working ESNR Committee on
Neuroradiological Practices in Neuroradiology. European Society of
Neuroradiology.
AB - In order to achieve an overview of neuroradiology in Europe a questionnaire was
sent to all ESNR National Delegates. The answers received were submitted to a
data-based analysis, leading to the conclusion that neuroradiology is an
expanding discipline among neurological sciences.
PMID- 9763348
TI - Laboratory diagnosis of hereditary thrombophilia.
AB - Genetic defects of antithrombin (AT) or one of the components of the protein C
pathway are associated with hereditary thrombophilia. Laboratory assays are
currently available to diagnose and type hereditary thrombophilia due to
deficiency or dysfunction of one of the anticoagulant factors antithrombin (AT),
protein C (PC) and protein S (PS), and APC resistance without the need of DNA
analysis. There are no functional tests for the prothrombin mutant G20210A and
thrombomodulin mutations, which can be diagnosed by a PCR-based test or by gene
analysis, respectively. Hereditary AT deficiency is classified in a quantitative
type I and three functional type II deficiencies affecting the reactive site
(RS), heparin binding site (HBS), or pleiomorphic site of the AT protein. All
four types of hereditary AT deficiencies can be diagnosed by a heparin cofactor
assay and one immune assay in combination with crossed immunoelectrophoresis of
the AT protein. The combination of an enzyme-linked immunoadsorbent assay (ELISA)
and a functional Protac-APTT-based assay for PC will detect quantitative type I
and dysfunctional type II PC deficiencies. There is a significant overlap in PC
antigen and functional levels between heterozygotes of PC deficiency and normals
leaving a gray zone of uncertainty in differentiating congenital PC deficiency
and normal individuals. Accurate diagnosis of hereditary PS deficiency should be
a combination of tests aimed to measure free PS activity and antigen and total PS
antigen levels. APTT-, Xa-, and RVVT-based APC-resistance tests, when test
plasmas are diluted in factor V deficient plasma, have increased in sensitivity
and specificity to 100% for the discrimination of normal individuals from
heterozygotes and homozygotes for factor V Leiden. The RVVT-based APC-resistance
test provides better separation of factor V Leiden and normals in the various
clinical settings, lupus anticoagulant in particular. The modified APC-resistance
tests also claim a separation between heterozygotes and homozygotes for factor V
Leiden in the normal population, asymptomatic subjects, and thrombosis patients.
Below a certain cut-off level, a minor overlap of normalized APC ratios between
heterozygotes and homozygotes for factor V Leiden of thrombosis patients has been
shown in one study, which still points to the need to perform the more time
consuming and expensive DNA test to identify heterozygotes from the more
clinically significant homozygotes. The prothrombin-based APC-resistance test,
which measures thrombin activated factor Va in highly diluted test plasma,
appears to be the most sensitive and specific of all APC-resistance tests and
separates normal individuals from heterozygotes and heterozygotes from
homozygotes for factor V Leiden without the need of confirmation by a DNA test.
PMID- 9763349
TI - Screening test for thrombophilic patients: which tests, for which patient, by
whom, when, and why?
AB - In the past two decades, several mechanisms leading to thrombophilia have been
elucidated, and corresponding laboratory tests developed. At a time of financial
constraints, it is crucial to distinguish between the tests of proven value
(which can modify the therapeutic attitude toward the patient and/or his family)
from those of unproven value. We have listed in the first category determination
or measurement of factor V Leiden, factor II G20210A, antithrombin, protein C,
protein S, as well as antiphospholipid antibodies and hyperhomocysteinemia. A
combined clinical and laboratory approach taking into account the history of the
patient and his family, the prevalence of the defects, and also the accuracy of
the tests should allow tailoring a laboratory testing program to each individual
patient. It is essential to keep in mind that the more difficult task is not to
perform the tests, but to consider who will benefit from testing both for
prevention and therapy of venous thromboembolism. The present review provides
answers to some of these issues. These answers should, however, be considered as
provisional because new findings and study results will certainly modify them in
the future.
PMID- 9763350
TI - Molecular biology and pathophysiology of APC resistance: current insights and
clinical implications.
AB - APC resistance is often associated with the occurrence of a single point mutation
in factor V (factor VLeiden) at a predominant cleavage site for the natural
anticoagulant, activated protein C (APC). In this article we will discuss the
effects of this mutation (Arg506-->Gln) on the down-regulation of factor Va
cofactor activity and on thrombin formation by APC in model systems and in
plasma. Our studies on the effects of APC on thrombin formation in plasma
resulted in the development of a new method for the screening of APC resistance
that is based on measurement of the effect of APC on the endogenous thrombin
potential (the time integral of thrombin generated in clotting plasma). It
appeared that sensitivities for APC determined via this method were considerably
affected by the use of oral contraceptives (OC) and that women who use OC become
acquired APC resistant. The fact that acquired APC resistance in women who use
third-generation OC was more pronounced than in users of second-generation OC may
explain the further increased risk for venous thrombosis associated with the use
of third-generation OC.
PMID- 9763351
TI - The anticoagulant potential of the protein C system in hereditary and acquired
thrombophilia: pathomechanisms and new tools for assessing its clinical
relevance.
AB - The diagnosis of the procoagulant system is routinely based on activated partial
thromboplastin time (APTT) and PT results indicating only a bleeding tendency.
Routine screening tests for thrombophilia providing an objective measure of the
anticoagulant potential of the blood are still lacking. Only antithrombin is
determined quite frequently. The recent findings of activated protein C (APC)
resistance have demonstrated the importance of the PC anticoagulant system in
inherited thrombophilia. A vast body of evidence from in vitro and animal
experiments as well as from recent clinical studies is presented revealing that
the PC system potential plays a major role in maintaining the hemostatic balance
at a variety of clinical conditions. It is suggested that acquired defects in the
PC system are an underestimated cause for clinically induced venous thrombosis.
New screening assays for the PC system potential are presented, which already
indicate quite well congenital as well as acquired interferences of the PC system
potential.
PMID- 9763352
TI - A protein C pathway (PCP) screening test for the detection of APC resistance and
protein C or S deficiencies.
AB - A new automated method for screening defects in the Protein C Pathway (PCP) was
evaluated. The "PCP test" is based on a phospholipid-rich Russells viper venom
reagent, insensitive to heparin and lupus anticoagulants. To minimize
interference from other clotting variables, ratios of the clotting time with and
without the addition of a protein C activator were usually determined. Plasma
samples from healthy volunteers, patients untreated or on oral anticoagulants,
patients with factor V Leiden with and without treatment, and patients with
protein C and/or S deficiencies were tested. Mixing patient plasmas 1:1 with
individual plasmas deficient in factor V, protein C or S was evaluated for
identifying the nature of defects by shortening the screening test. The PCP test
was found to be sensitive to APC resistance due to factor V Leiden and by mixing
with factor V deficient plasma was also useful despite the effects of oral
anticoagulants. Results in the group of patients with previous low protein C or S
levels suggest that the method has a better sensitivity to protein C than to
protein S deficiency. The automated test was simple to use and gave a between-run
coefficient of variation below 3% on normal plasmas.
PMID- 9763353
TI - Factor V:Q506 mutation-resistance to activated protein C (APC): clinical
implications with respect to family screening.
AB - Resistance to activated protein C (APC), which is almost exclusively caused by a
point mutation in the factor V gene (FV:Q506 mutation or FV Leiden) is a recently
discovered, prevalent risk factor for the occurrence of venous thromboembolism.
It is unknown whether relatives of known patients with this mutation should be
screened for the presence of the mutation and what the consequences for
asymptomatic carriers would be. This paper addresses the possible benefits and
disadvantages of family screening of patients with venous thromboembolism who
carry the mutation. Possible prophylactic strategies are discussed and weighed on
the basis of estimated incidence rates of venous thromboembolism that are deduced
from known relative risks and available population studies.
PMID- 9763354
TI - Epidemiology of factor V Leiden: clinical implications.
AB - Inherited resistance to activated protein C (APC) has been recently recognized as
a novel cause underlying venous thrombophilia. In most cases APC resistance is
due to a single point mutation in the factor V gene leading to a replacement of
Arg506 with Gln (factor V Leiden). Factor V Leiden allele is present in about 5%
of the Caucasian individuals (Europeans, Jews, Israeli Arabs, and Indians) and is
virtually absent in Africans, Asians, and races with Asian ancestry such as
Amerindians, Eskimos, and Polynesians; this suggests a single origin of the
mutation, which has been proven by haplotype analysis. A low prevalence of the
mutation (1%) was noticed in African-Americans for recent racial admixture.
Factor V Leiden presents not a major role as risk factor for arterial thrombosis,
while it is present in 18% of Caucasian patients with venous thrombosis. This
high incidence prevalence mirrors the incidence in the corresponding general
populations and can be even higher in some areas according to the ethnic
background. Conversely, factor V Leiden is usually not found in non-Caucasian
thrombotic patients; this could give reason of the lower incidence of venous
thrombotic disease in Africa and Asia in comparison with Europe. Therefore,
screening for factor V Leiden is suggested for all Caucasian individuals with
previous venous thrombosis; inclusion criteria for the screening should not be
stringent because clinical manifestations associated with the mutant genotype can
be also mild or secondary to circumstantial risk factors or manifesting at
advanced age. Factor V Leiden can act also as concurrent risk factor in
individuals with deficiency of natural inhibitors or mild hyperhomocysteinemia.
So far, screening for the mutation in individuals with no history of thrombosis
is recommended only for relatives of proband patients identified as carriers; the
available data do not justify indiscriminate screening before risk situations
such as oral contraceptives intake, pregnancy, or high-risk surgery.
PMID- 9763355
TI - Hyperhomocysteinemia and atherothrombotic disease.
AB - Hyperhomocysteinemia is an independent risk factor for atherothrombotic disease.
The mechanism by which homocysteine induces atherosclerosis and thrombosis is not
fully understood. Data on arterial histology in humans with homocystinuria and
mild hyperhomocysteinemia are limited. In vitro studies as well as studies in
animals and humans indicate that hyperhomocysteinemia induces dysfunction of the
vascular endothelium, with loss of endothelium-dependent vasodilation and
endothelial antithrombotic properties, and proliferation of vascular smooth
muscle cells, which are key processes in current models of atherogenesis and
thrombosis. One of the hypotheses is that homocysteine can lead to cellular
dysfunction through a mechanism involving oxidative damage but future studies in
humans are needed to confirm this. Studies in hyperhomocysteinemic vascular
patients have shown that endothelial antithrombotic properties appear to be more
severely impaired than in similar patients with normohomocysteinemia.
Furthermore, impaired endothelium-dependent vasodilation has been observed in
clinically healthy hyperhomocysteinemic subjects in whom no abnormalities were
found in endothelial antithrombotic properties. Future studies involving
homocysteine-lowering treatment in hyperhomocysteinemic patients with vascular
disease and in clinically healthy hyperhomocysteinemic subjects are necessary to
investigate the mechanisms by which homocysteine causes atherothrombotic
disorders in humans.
PMID- 9763356
TI - Hyperhomocysteinemia and venous thrombosis.
AB - In recent years hyperhomocysteinemia has been established as a new risk factor
for neural tube defects, arterial cardiovascular disease, and venous thrombosis.
Concerning vascular problems, it first became clear that hyperhomocysteinemia
might be (though not proven) a risk factor for arterial disease as observed in
case-control studies, as well as in prospective analysis. More recently, the
subject of hyperhomocysteinemia and venous thrombosis has received much
attention. In this article, we discuss the issue of hyperhomocysteinemia, in
general, the known causes of hyperhomocysteinemia and the association with venous
thrombosis. Special attention is given to the value of the methionine loading
test to diagnose hyperhomocysteinemia. An association of venous thrombosis and
hyperhomocysteinemia has now been documented in several case control studies, but
only in one prospective analysis. Thus far, there is limited evidence for a
causal relationship for mild hyperhomocysteinemia in venous thrombosis. Briefly,
the possible mechanisms of how hyperhomocysteinemia can lead to venous thrombosis
are discussed. The article ends with therapeutic options to treat
hyperhomocysteinemia (hyperhomocysteinemia can easily be treated with vitamins)
and the description of a study that is presently being undertaken in an
international multicenter design. This placebo-controlled study might resolve the
question of whether lowering of homocysteine levels is of any clinical relevance
in preventing recurrent venous thrombosis.
PMID- 9763357
TI - Rapid D-dimer assays to exclude deep venous thrombosis and pulmonary embolism:
current status and new developments.
AB - Studies measuring the fibrin degradation product D-Dimer (DD) using enzyme-linked
immunosorbent assays (ELISA) in patients suspected of deep venous thrombosis
(DVT) or pulmonary embolism (PE) suggest that it is possible to exclude DVT/PE
when the DD level is below a certain cut-off value. However, ELISA methods are
time-consuming, bare high costs, and are only available in experienced
laboratories. For this reason several rapid and less costly DD assays have been
recently developed. This article reviews the current literature about rapid latex
and ELISA DD assays in the diagnostic approach of DVT and PE. Two new latex
assays seem suitable in clinical practice. The most extensively studied assay is
the so-called SimpliRed DD, an autologous red cell agglutination test that can be
performed on fresh whole blood. For DVT a sensitivity (Sens) and a negative
predictive value (NPV) of 89-100% and 95-100%, respectively, have been reported,
for PE 94-100% and 98-100%, respectively. The second test, Tinaquant, is a
quantitative latex assay. Sens and NPV for DVT of 99% and 93% have been reported
in one study. Two rapid ELISA assays have been investigated. The most extensively
studied is the VIDAS DD assay, a fully automated quantitative ELISA method. Sens
and NPV of 94-100% and 92-100% for DVT and both 100% for PE have been reported.
For the other rapid ELISA, Instant IA DD, Sens and NPV of 92-93% and 76-77% have
been reported for DVT. The last one is a qualitative assay giving only positive
or negative results. These results show that low concentrations of plasma DD
measured by especially SimpliRed or VIDAS DD, might be used to reliably rule out
DVT or PE in clinically suspected patients. Tinaquant seems promising and has to
be evaluated further. As for standard ELISA, increased DD concentrations are of
no use because of the low specificity of the assays. Future studies should assess
the clinical usefulness of both assays in management trials under routine
conditions, in the frame of clinical decision-making diagnostic processes to
prove that withholding further noninvasive testing and/or anticoagulants in
patients with a low or negative DD is safe. Strategies to identify patients with
false-negative results should be developed.
PMID- 9763358
TI - Rational diagnosis of deep vein thrombosis (RADIA DVT) in symptomatic outpatients
with suspected DVT: simplification and improvement of decision rule analysis for
the exclusion and diagnosis of DVT by the combined use of a simple clinical
model, a rapid sensitive D-dimer test and compression ultrasonography (CUS).
AB - The diagnosis of deep vein thrombosis (DVT) in outpatients is difficult to
establish. The classical clinical signs of DVT are unspecific and found in
several other conditions besides DVT. Therefore, these patients are subjected to
elaborate, expensive invasive or noninvasive procedures that actually confirm DVT
in only 20-30% of patients in this setting. A prospective management decision
study, based on a pretest clinical probability (PCP) estimation, compression
ultrasonography (CUS), and a rapid enzyme-linked immunoadsorbent assay (ELISA) D
dimer test, is proposed. The PCP model of Wells allows for reasonably accurate
classification of patients into low, moderate and high probability for suffering
DVT. Combined with CUS, high predictability is achieved. The D-dimer assays
presently available can be rapidly performed and are accurate to a high degree,
especially in ruling out DVT. It is proposed to establish a "Rational Diagnosis
of Deep Vein Thrombosis (RADIA DVT)" model to be tested in a large number of
patients with suspected DVT. This model would be less expensive to perform and
likely yield a highly accurate diagnosis on the basis of which anticoagulant
therapy could be initiated or withheld.
PMID- 9763359
TI - The place of D-dimer testing in an integrated approach of patients suspected of
pulmonary embolism.
AB - When a patient is suspected of having pulmonary embolism (PE), the first
procedure performed in most institutions is lung scintigraphy. Here we propose an
alternative diagnostic strategy based on the following sequential combination of
procedures: clinical assessment, D-dimer measurement, ultrasonography of lower
limbs, and lung scan. This integrated approach may rule out PE in the majority of
outpatients suspected of PE and permits district hospitals without lung-scan
facilities to manage approximately 50% of outpatients without referral. D-dimer
alone will exclude PE in about 30% of patients at low cost. This stepwise
strategy is especially useful because only 20-35% of patients suspected of PE
really have the disease. Thus, in the majority of patients, ruling out the
disease has replaced ruling in the disease.
PMID- 9763360
TI - Rational diagnosis of pulmonary embolism (RADIA PE) in symptomatic outpatients
with suspected PE: an improved strategy to exclude or diagnose venous
thromboembolism by the sequential use of a clinical model, rapid ELISA D-dimer
test, perfusion lung scan, ultrasonography, spiral CT, and pulmonary angiography.
AB - A prospective management decision analysis for the exclusion and diagnosis of
pulmonary embolism (PE) based on pre-test clinical probability (PCP) estimation
for PE, a rapid ELISA D-dimer test, perfusion lungscan (P-scan), CUS, spiral CT,
and pulmonary angiography is proposed. The modified PCP model for PE of Wells et
al. allows reasonably accurate classification of patients with no, low, moderate,
and high probability for PE. The combined rational use of the evidence-based
noninvasive imaging techniques P-scan, CUS, and spiral CT with the rapid ELISA D
dimer test and PCP will reduce the need for invasive pulmonary angiography to
perhaps 10 to 15% of patients, who initially presented with suspected PE. A
Rational Diagnosis of Pulmonary Embolism (RADIA PE) model is proposed for testing
in a large multicenter study of patients with suspected PE.
PMID- 9763361
TI - Of muscles, merosin, and migration.
PMID- 9763362
TI - . . . But will it play in Peoria?
PMID- 9763363
TI - Detection of perineural spread: fat is a friend.
PMID- 9763364
TI - No drug is benign.
PMID- 9763365
TI - Intracranial angioplasty: a little science enters into the mix.
PMID- 9763366
TI - Neuroimaging manifestations and classification of congenital muscular
dystrophies.
AB - BACKGROUND AND PURPOSE: Recent work has shown that up to 50% of patients with
congenital muscular dystrophies (CMDs) have abnormalities of the brain that can
be detected by brain MR imaging. We attempted to determine whether brain MR
imaging is useful for the diagnosis and classification of patients with CMDs.
METHODS: The brain MR studies of 12 patients with biopsy-proved CMDs were
reviewed retrospectively. Using information available in the literature regarding
associated brain anomalies as a guide, an attempt was made to classify the
patients in terms of "pure" CMD, CMD with occipital agyria, Fukuyama CMD, muscle
eye-brain disease, or Walker-Warburg syndrome. RESULTS: All the patients were
easily classified into one of four groups: pure CMD (four patients), Fukuyama CMD
(four patients), muscle-eye-brain disease (two patients), or Walker-Warburg
syndrome (two patients). Patients with pure CMD had diffuse central cerebral
hypomyelination with mild pontine and cerebellar hypoplasia. Patients with
Fukuyama CMD had diffuse central cerebral hypomyelination, cerebellar
polymicrogyria (with or without cysts), frontal polymicrogyria, a variable degree
of hypoplasia of the pons and cerebellar vermis, and a variable occipital
cobblestone cortex. Patients with muscle-eye-brain disease had cerebellar
polymicrogyria (with or without cysts), absence of the septum pellucidum, diffuse
cerebral cortical dysplasia, pontine and cerebellar vermian hypoplasia, patchy
hypomyelination, and variable callosal hypogenesis and hydrocephalus. Patients
with Walker-Warburg syndrome had diffuse cerebral cobblestone cortex, absence of
cerebral and cerebellar myelin, cerebellar polymicrogyria (with or without
cysts), pontine and cerebellar vermal hypoplasia, hydrocephalus, and variable
callosal hypogenesis. CONCLUSION: MR imaging shows distinctive brain anomalies
that allows patients with CMD to be classified into four distinct groups that are
consistent with known disorders.
PMID- 9763367
TI - MR of the normal neonatal brain: assessment of deep structures.
AB - BACKGROUND AND PURPOSE: MR imaging is a powerful tool for studying the anatomy of
and the developmental changes that occur in the brain. The purpose of this
project was to determine which structures can be distinguished on standard spin
echo MR sequences of a normal neonatal brain and with what frequency they can be
identified. METHODS: The T1- and T2-weighted spin-echo MR images of 12 term
neonates, all of whom had normal neonatal courses and were neurologically and
developmentally normal at age 12 months, were reviewed retrospectively. All
structures that differed in signal intensity from unmyelinated gray matter and
unmyelinated white matter were recorded. RESULTS: In general, myelinated gray
matter structures, such as cranial nerve nuclei and other nuclei of the brain
stem and deep cerebrum, were the structures best seen on T2-weighted images. Most
of these nuclei were seen in 75% to 100% of our subjects on T2-weighted images.
They were seen less well on T1-weighted images. Myelinated white matter
structures, particularly axonal tracts, were the structures best seen on T1
weighted images. The medial and lateral lemnisci, median longitudinal fasciculus,
optic tracts, superior and inferior cerebellar peduncles, and the posterior limbs
of the internal capsules were seen in 75% to 100% of our subjects on T1-weighted
images. Except for the posterior limbs of the internal capsules, these structures
were seen less well on T2-weighted images. CONCLUSION: A large number of small
structures, such as the nuclei of the brain stem and deep cerebral nuclei, can be
routinely identified on standard spin-echo MR imaging sequences. A knowledge of
these structures is essential to proper interpretation of imaging studies in
neonates and infants.
PMID- 9763368
TI - Contrast-enhanced three-dimensional fast imaging with steady-state precession
(FISP) MR angiography of supraaortic vessels: preliminary results.
AB - BACKGROUND AND PURPOSE: The purpose of this study was to assess the effectiveness
of contrast-enhanced fast three-dimensional (3D) MR angiography in depicting both
the carotid and vertebral arteries in their cervical portions and to compare MR
angiography with conventional angiography for the evaluation of arteriosclerotic
disease. METHODS: Twenty-seven patients with ischemic cerebral events in the
anterior (n = 18) and posterior (n = 9) circulation underwent contrast-enhanced
3D MR angiography in the coronal plane. MR angiograms were examined in a blinded
fashion by two observers independently. Stenosis was classified according to the
appearance of the residual lumen (no stenosis, mild stenosis, moderate stenosis,
severe stenosis, occlusion). Conventional angiography was used as the standard of
reference. RESULTS: Proximal great vessels and carotid siphons were not
assessable on MR angiograms in 35% of cases owing to limited coverage. All
cervical and petrous segments of the internal carotid arteries (ICAs) and 93% of
the extracranial vertebral arteries were assessable. Flow-related artifacts were
observed in seven cases of severe stenosis, including three with signal void at
the site of narrowing and four with signal loss in the distal ICA. Interobserver
agreement was good and significant. Overall agreement between 3D MR angiography
and conventional angiography was good for the anterior and posterior circulations
despite a tendency toward overestimation of stenoses on MR angiograms. Clinically
relevant stenoses and occlusions were correctly identified on 3D MR angiograms,
providing good sensitivity and specificity. CONCLUSION: Contrast-enhanced 3D MR
angiography is a promising tool for assessing arteriosclerotic lesions of
supraaortic vessels. Further studies with larger groups are required to determine
its value for patient care.
PMID- 9763369
TI - Abnormal origin of the vertebral artery from the common carotid artery.
AB - An abnormal origin of the vertebral artery from the common carotid artery (VA-CC)
may occur on the right or left side with different embryonic mechanisms. We
describe a patient with a double developmental anomaly, a right VA-CC and a right
aortic arch. The rotation of the aortic arch caused a "twist" of the embryonic
mechanisms of VA-CC and misdirected the differential diagnosis of the embryonic
mechanisms at first glance. We discuss the pivotal points in differentiating the
embryonic mechanisms of VA-CC.
PMID- 9763370
TI - Imaging of perineural tumor spread from palatal carcinoma.
AB - Carcinomas of the hard or soft palate are known to spread perineurally along
palatine branches of the maxillary nerve. Imaging of perineural tumor spread from
the palate has been underemphasized in the imaging literature. We report the
findings from eight patients in whom spread from primary cancers of the palate
was seen along the palatine nerves. Indications of perineural spread include
enlargement or excessive enhancement of a nerve, or abnormal density/signal
intensity, enhancement, or widening of the pterygopalatine fossa, cavernous
sinus, or Meckel's cave.
PMID- 9763371
TI - Osseous anatomy of the pterygopalatine fossa.
PMID- 9763372
TI - Sudden hearing loss: frequency of abnormal findings on contrast-enhanced MR
studies.
AB - BACKGROUND AND PURPOSE: Our purpose was to determine the frequency of abnormal
findings on contrast-enhanced high-resolution MR imaging studies in patients with
sudden hearing loss. METHODS: Seventy-eight consecutive patients with sudden
hearing loss underwent contrast-enhanced MR imaging of the temporal bone,
cerebellopontine angle, and brain. Additional tests included audiologic
examination, electrocochleography, fistula tests, and serologic tests for viral
agents and autoimmune disorders. RESULTS: Probable causes of the sudden hearing
loss in these patients included viral or immune-mediated disease, Meniere
disease, vascular disorder, syphilis, neoplasm, multiple sclerosis, and
perilymphatic fistula. Twenty-four (31%) of the 78 patients were found to have
abnormal imaging results early in the course of their work up and treatment.
CONCLUSION: The prevalence of abnormal findings on contrast-enhanced MR studies
is higher than previously reported in patients with sudden hearing loss.
PMID- 9763373
TI - Spontaneous labyrinthine hemorrhage in sickle cell disease.
AB - We report the clinical and MR imaging findings in two African-American patients
with manifestations of sickle cell disease affecting the inner ear. Both suffered
sudden-onset sensorineural hearing loss and vestibular symptoms, and both had
high labyrinthine signal on T1-weighted MR images attributed to labyrinthine
hemorrhage. Follow-up studies of the first patient revealed a decrease in
abnormal vestibular signal. Careful attention to the labyrinth on T1-weighted MR
images can reveal vestibulocochlear clinical findings in sickle cell patients,
with important implications for management and prognosis.
PMID- 9763374
TI - Choroidal hemangioma: MR findings and differentiation from uveal melanoma.
AB - BACKGROUND AND PURPOSE: The aim of this study was to establish the MR imaging
characteristics of choroidal hemangioma and to compare them with those of uveal
melanoma. METHODS: Among 41 patients examined at 1.5 T (4-cm surface coil, T1
weighted and fast spin-echo T2-weighted sequences), 25 had uveal melanoma and 16
had circumscribed choroidal hemangioma. After i.v. bolus injection of
gadopentetate dimeglumine, dynamic and T1-weighted sequences were acquired.
RESULTS: In patients with choroidal hemangioma, uniform signal characteristics
were detected on fast T2-weighted images. In 15 of 16 patients with choroidal
hemangioma, lesions were isointense with vitreous on fast spin-echo T2-weighted
images, whereas lesions in 24 of 25 patients with uveal melanoma were
hypointense. Signal characteristics of uveal melanoma and hemangioma did not
differ significantly on plain T1-weighted images. Enhancement was earlier and
much stronger for circumscribed choroidal hemangioma than for uveal melanoma.
After i.v. bolus application of gadopentetate dimeglumine, the increase of signal
intensity was higher for circumscribed choroidal hemangioma (signal intensity
ratio, 5.8) than for uveal melanoma (signal intensity ratio, 2.2). CONCLUSION:
Circumscribed choroidal hemangioma may be difficult to differentiate from
melanoma by ophthalmologic examination. Differentiation may not be possible if
direct viewing of uveal space-occupying lesions is hampered by opaque vitreous
media. The characteristic findings on fast spin-echo T2-weighted MR images and
early enhanced images aid in differentiating choroidal hemangioma from uveal
melanoma.
PMID- 9763375
TI - Superior blowout fracture of the orbit: the blowup fracture.
AB - We describe a patient who sustained a blowout fracture of the superior orbital
roof without an orbital rim fracture. The initial CT study (obtained with 10-mm
thick sections) did not show herniation of the intraorbital fat into the anterior
cranial fossa; however, thin (3-mm-thick) direct orbital sections showed a
fracture of the midportion of the superomedial orbital roof with displacement of
the fracture fragment into the anterior cranial fossa.
PMID- 9763376
TI - Traumatic subluxation of the globe into the maxillary sinus.
AB - We report a case of complete traumatic subluxation of the globe into the
maxillary sinus as documented by CT. The cornea sustained a mild epithelial
abrasion but the globe was otherwise intact without signs of trauma.
PMID- 9763377
TI - An unusual cause of otalgia.
PMID- 9763378
TI - Neurotoxic potential of gadodiamide after injection into the lateral cerebral
ventricle of rats.
AB - PURPOSE: Results of a previous report showed that, if administered by
intraventricular injection to access tissue normally protected by the blood-brain
barrier, gadopentetate dimeglumine produced acute excitation, persistent ataxia,
and widespread brain lesions in rats at 5-micromol/g brain but not at 3.8
micromol/g brain. The present study using gadodiamide was undertaken to see
whether the effects were agent-specific. METHODS: Rats, surgically prepared with
a lateral ventricular cannula, were administered a slow injection at 2 microL/min
of gadodiamide into the lateral ventricle, and behavioral and neuropathologic
changes were noted. RESULTS: Both gadodiamide and gadopentetate dimeglumine
produced focal and generalized myoclonus over several hours. Gadodiamide did not
produce the medium-term tremor or persistent ataxia seen after treatment with
gadopentetate dimeglumine. Neuropathologic changes developed over 1 to 3 days and
took three distinct forms: vacuolated thalamic lesions closely resembling those
produced by gadopentetate dimeglumine; small but similar vacuolated symmetrical
caudate lesions not produced by gadopentetate dimeglumine; and severe swelling
and astrocytic hypertrophy and hyperplasia in the cerebellar vermis, again not
produced by gadopentetate dimeglumine. Unlike gadopentetate dimeglumine,
gadodiamide produced no spinal cord lesions. The cerebellar changes were seen at
1.25-micromol/g brain and above, behavioral changes at 2.5-micromol/g brain and
above, and thalamic and caudate lesions at 10-micromol/g brain, the maximal dose
used. Markedly reducing the rate of injecting the same volume over 28 hours
prevented the acute excitation but did not reduce the severity of the morphologic
effects. CONCLUSION: The acute excitatory effects of high intraventricular doses
of gadopentetate dimeglumine and gadodiamide are similar and appear to be
attributable to local action at the infusion site, but differences exist between
the two agents in the character and topography of the distant morphologic
changes. The cerebellum was the brain area most sensitive to gadodiamide in this
experimental model. It is unlikely that gadodiamide would gain access to the
brain at these tissue doses when used intravenously for conventional clinical
imaging, but our experimental model suggested that it had some unexpectedly
specific neuropathologic potential.
PMID- 9763379
TI - Hemodynamic effects of middle cerebral artery stenosis and occlusion.
AB - BACKGROUND AND PURPOSE: Middle cerebral artery (MCA) stenosis and occlusion may
cause ischemic symptoms through both hemodynamic and embolic mechanisms. The
purpose of this investigation was to determine the hemodynamic effects of these
lesions. METHODS: Ten patients with angiographically confirmed symptomatic
occlusion (n = 5) or stenosis (n = 5) of the M1 segment of the MCA were studied
by clinical examination, arteriography, and positron emission tomography (PET).
Arterial supply to the distal MCA territory was classified from a review of the
angiogram as being through the stenosis or from pial collaterals from anterior or
posterior cerebral arteries. Regional measurements of cerebral blood flow,
cerebral blood volume, cerebral rate of oxygen metabolism, oxygen extraction
fraction, and ratio of cerebral blood volume/cerebral blood flow (mean vascular
transit time, MTT) were obtained using PET. Hemodynamic status was categorized
from PET scans as stage 0, normal hemodynamics; stage 1, autoregulatory
vasodilatation (increased MTT); or stage 2, increased oxygen extraction fraction.
RESULTS: Of five patients with MCA occlusion, three had autoregulatory
vasodilatation (stage 1) and two had increased oxygen extraction fraction distal
to the lesion (stage 2). The MCA territory was supplied solely by pial
collaterals in all five patients. Four of the five patients with focal MCA
stenosis had normal hemodynamics (stage 0). One patient had stage 1 hemodynamic
status. Blood flow to the MCA territory was through the stenosis in all patients;
no pial collaterals were identified. CONCLUSION: The frequency of hemodynamic
compromise in patients with MCA occlusion is high. Pial collateralization is not
a specific sign of increased oxygen extraction fraction in patients with MCA
occlusion.
PMID- 9763380
TI - MR detection of hyperacute parenchymal hemorrhage of the brain.
AB - BACKGROUND AND PURPOSE: The detection of hemorrhage in acutely ill patients is
crucial to clinical management. The MR features that allow diagnosis of
intracerebral hematomas of less than 24 hours' duration are described and the
mechanistic basis of these features is investigated. METHODS: The clinical MR
features of seven confirmed hyperacute intracerebral hematomas were compared with
those of experimentally induced hematomas in a rat model in which detailed
analyses of iron metabolism and morphometry were performed. RESULTS: In all
patients and all animals, a hypointense rim on T2-weighted spin-echo images that
was less marked on T1-weighted spin-echo images was seen surrounding a central
isointense or heterogeneous region of hyperacute hematoma. Histologically, the
clot showed interdigitation of intact erythrocytes and tissue at the hematoma
tissue interface without significant hemosiderin, ferritin, or phagocytic
activity. Biochemically, the iron from the extravasated blood was present only as
heme proteins within the first 24 hours. CONCLUSION: The hypointense rim on T2
weighted images, and to a lesser extent on T1-weighted images, is a distinctive
feature of hyperacute hematoma. This pattern is consistent with magnetic
susceptibility variations of paramagnetic deoxygenated hemoglobin within intact
erythrocytes at a microscopically irregular tissue-clot interface. The detection
of hemorrhage is important in the management of patients with acute stroke.
PMID- 9763381
TI - Small rosarylike infarctions in the centrum ovale suggest hemodynamic failure.
AB - BACKGROUND AND PURPOSE: Lesions in the centrum ovale may be classified as
microangiopathic (lacunar) lesions and hemodynamic infarctions. To distinguish
between them, a size of more than 2 cm has been postulated for hemodynamic
infarctions. The reliability of this criterion was assessed with MR imaging.
METHODS: In 16 patients with unilateral or bilateral occlusion or high-grade
stenosis of the internal carotid artery (ICA), CO2 testing revealed an
ipsilateral hemodynamic failure. Each hemisphere in these patients was assessed
separately for the presence and size of centrum ovale lesions. RESULTS: Five of
the 16 patients suffered from large cortical infarctions with a probable embolic
pathogenesis. In the remaining 11 patients (22 hemispheres), a hemodynamic
failure was found in 15 hemispheres, due to occlusion (13 hemispheres) or high
grade ICA stenosis (two hemispheres). MR imaging revealed centrum ovale
infarctions with a size of more than 2 cm in three of the 15 hemispheres. In
eight hemispheres, multiple small lesions (< 1.5 cm; three to 30 per hemisphere)
could be found with a rosarylike or sickle-shaped distribution. In none of these
eight cases did MR images show lacunar infarctions in the typical regions of the
brain. CONCLUSION: Our results favor the assumption that the MR finding of
multiple small (< 1.5 cm) rosarylike lesions in the centrum ovale seems to be
typical in patients with hemodynamic failure due to severe ICA disease.
PMID- 9763382
TI - Acute postictal cerebral imaging.
AB - BACKGROUND AND PURPOSE: Imaging of postictal patients is performed to investigate
causes of seizure, such as space-occupying lesions or other "structural"
processes; however, abnormalities may be found that reflect physiological or
pathologic alterations due to seizure activity. The purpose of this study was to
determine the brain imaging findings in patients in the immediate postictal
period who presented with altered mental status or weakness. METHODS: Ten
patients who were examined for postictal neurologic derangement were studied
(nine by CT and one by MR imaging) within 12 hours of ictus. Four of the CT
studies and the one MR study included administration of contrast material. Follow
up examinations were performed 1 day to 11 months later. These studies were
reviewed retrospectively. RESULTS: CT findings included focal gyral swelling
(10/10), effacement of adjacent cortical sulci (2/10), decreased gyral
attenuation by CT (8/9), and mild to moderate gyral enhancement after injection
of contrast material (5/5). MR imaging findings included gyral swelling,
increased signal intensity on T2-weighted images, and enhancement after injection
of contrast agent. The abnormalities were located in the frontal lobes (9/10,
with bilateral involvement in 6/10), the parietal lobes (4/10), the temporal
lobes (2/10), and the occipital lobe (1/10). Follow-up studies revealed complete
or subtotal reversal of these abnormalities. CONCLUSION: Although there are
numerous causes of gyral swelling and enhancement, such as infarction and
neoplasm, if these conditions are reversible and correspond to clinical findings,
then the differential diagnosis is narrowed to postictal change, reversible
ischemia, complicated migraine, or resolved inflammation/infection.
PMID- 9763383
TI - MR identification of white matter abnormalities in multiple sclerosis: a
comparison between 1.5 T and 4 T.
AB - BACKGROUND AND PURPOSE: Although MR spectroscopy and functional MR imaging of the
brain have been successful at 4 T, conventional fast spin-echo imaging of the
brain at 4 T has not been adequately evaluated. The purpose of this study was to
compare the detection of white matter abnormalities in multiple sclerosis (MS) at
1.5 T and 4 T. METHODS: Fifteen patients with clinically definite MS were imaged
at both 1.5 T and 4 T within a 1-week period. Comparison was made between fast
spin-echo long-TR images at both field strengths. Pulse sequences were tailored
to maximize resolution and signal-to-noise ratio in clinically relevant imaging
times (< 7 min). Four interpreters independently reviewed the images obtained at
both field strengths in separate sessions and evaluated them for lesion
identification, size, characterization, and subjective resolution. Differences in
interpretations at 1.5 T and 4 T were subsequently recorded. RESULTS: Images
obtained at 4 T showed a mean of 88 more lesions as compared with images obtained
at 1.5 T. All the lesions measured less than 5 mm and were typically aligned
along perivascular spaces. Twenty-five consensually identified lesions on 4-T
images were not seen at all on 1.5-T images. Moreover, 4-T images showed 56
additional consensually identified lesions, which were indistinct and seen only
in retrospect on 1.5-T images. These lesions were frequently (n = 48) identified
in large confluent areas of white matter signal intensity abnormality at 1.5 T.
All observers also agreed that 4-T images subjectively enhanced the perception of
normal perivascular spaces and small perivascular lesions. CONCLUSION: MR imaging
at 4 T can depict white matter abnormalities in MS patients not detectable at 1.5
T through higher resolution with comparable signal-to-noise ratio and imaging
times.
PMID- 9763384
TI - MR findings in growth hormone deficiency: correlation with severity of
hypopituitarism.
AB - BACKGROUND AND PURPOSE: Growth hormone deficiency may present as an isolated
deficit (IGHD) or in association with multiple deficiencies (MPHD). Previous
studies have not compared the MR imaging findings with the severity of
hypopituitarism. Our purpose was to determine whether MR imaging can distinguish
between IGHD and MPHD. METHODS: Forty-four patients with growth hormone
deficiency who were examined by MR imaging were included in this retrospective
study. On the basis of the endocrinologic findings, 21 were determined to have
IGHD and 23 to have MPHD. The presence, size, location, and morphologic
characteristics of the stalk, the neurohypophysis, and the adenohypophysis were
recorded in each case. Findings in the two groups were compared. Statistical
significance was determined by t-test. RESULTS: The stalk was normal in one
patient with IGHD and in none of those with MPHD; it was truncated or thin in 19
patients with IGHD (90%) and in only one with MPHD (4%); it was absent in 22
patients with MPHD (96%) and in only one patient with IGHD (5%). These
differences between the two groups were highly significant. In 81% of the IGHD
patients and in 91% of the MPHD patients the location of the neurohypophysis was
ectopic. This difference between the two groups was not significant. Among IGHD
patients, the adenohypophysis was of normal size in 13 patients (62%), small in
six (29%), and absent in two (9%); the corresponding findings in MPHD patients
were seven (30%), six (26%), and 10 (44%). CONCLUSION: The majority of IGHD
patients had a truncated or thin stalk and a normal or small adenohypophysis. An
absent stalk and adenohypophysis are characteristic of MPHD. MR imaging can
contribute to the prediction of the pattern and severity of hypopituitarism in
patients with growth hormone deficiency.
PMID- 9763385
TI - Differential aging of the human striatum: a prospective MR imaging study.
AB - BACKGROUND AND PURPOSE: Advancing age is associated with declines in motor
function; understanding age-related changes in the basal ganglia, therefore, is
imperative for comprehension of such functional changes. The purpose of this
study was to examine the age, sex, and hemispheric differences in volume of the
caudate nucleus, the putamen, and the globus pallidus. METHODS: In a sample of
148 healthy right-handed adults (18-77 years old) with no evidence of age-related
motor disorders, we estimated the volume of the head of the caudate nucleus, the
putamen, and the globus pallidus from MR images. RESULTS: The analyses revealed
bilateral age-related shrinkage of the head of the caudate nucleus and the
putamen in both sexes. In men, the age-related shrinkage of the caudate was
stronger on the left, whereas, in women, the opposite trend was evident. In both
sexes, age-related shrinkage of the right putamen was greater than of its left
counterpart. The mild bilateral age-related shrinkage of the globus pallidus was
observed only in men. In both sexes, we observed significant rightward asymmetry
in the putamen, significant leftward asymmetry in the caudate, and no asymmetry
in the globus pallidus. CONCLUSIONS: Bilateral age-related shrinkage of the
neostriatum is found in healthy adults. The shrinkage of the globus pallidus is
less pronounced and may be restricted to men only.
PMID- 9763386
TI - Abnormal cerebral activation associated with a motor task in Tourette syndrome.
AB - BACKGROUND AND PURPOSE: In Gilles de la Tourette syndrome, PET scanning and EEG
suggest an abnormal organization of the sensorimotor cortex and basal ganglia.
The purpose of this study was to use functional MR imaging to study activation in
the sensorimotor cortex in patients with Tourette syndrome. METHODS: From echo
planar images acquired during intermittent performance of a finger-tapping task,
the location of activated pixels was determined by means of conventional signal
processing methods. In five patients with Tourette syndrome and five healthy
volunteers, the number of activated pixels in the sensorimotor cortices and
supplementary motor areas were counted. The area over which the activation was
distributed was calculated. RESULTS: In the five patients, the average number of
pixels activated during the finger-tapping task in the sensorimoter cortices and
supplementary motor area (69.4 pixels) exceeded that in the volunteers (49.2
pixels). The difference was significant. The area over which the pixels was
distributed was significantly larger (25.4 vs 13.8 cm2). CONCLUSION: Motor
function is organized differently in patients with Tourette syndrome than in
healthy subjects.
PMID- 9763387
TI - Integral and shell-MIP display algorithms in MR and CT three-dimensional models
of the brain surface.
AB - BACKGROUND AND PURPOSE: Our purpose was to demonstrate the use of integral and
shell maximum intensity projection (shell-MIP) display algorithms in the 3-D CT
and MR depiction of cerebral gyral and surface venous anatomy and disorders.
These new algorithms are compared against MIP and shaded-surface-display (SSD)
algorithms. METHODS: Integral and shell-MIP displays were generated from a
specified number of proximal surface voxel layers in a 3-D model. Algorithmic
models were compared on nine contrast-enhanced spoiled gradient-recalled
acquisition in a steady state (SPGR) MR venograms for brain surface anatomic
identification and detail. Seven CT venograms were compared for conspicuity of
filling defects. Twelve contrast-enhanced preoperative planning 3-D MR models
were rated for neurosurgical utility. RESULTS: A shell-MIP score of 7.00 and an
integral score of 6.78 represented the highest mean subjective MR gyral quality
(1-10 scale) followed by an SSD score of 3.89 and an MIP score of 1.06. Mean
confidence scores for MR central sulcus identification (1-10 scale) were shell
MIP, 7.67; integral, 7.00; SSD, 3.22; and MIP, 1.00. Mean superficial venous
quality MR ratings (1-10 scale) were shell-MIP, 8.22; MIP, 7.39; integral, 7.00;
and SSD, 3.72. The mean number of cortical veins draining into each side of the
superior sagittal sinus on MR was as follows: MIP, 6.19; integral, 6.06; shell
MIP, 5.94; and SSD, 3.81. Mean confidence scores for filling defect
identification on CT venograms (1-5 scale) revealed a shell-MIP score of 4.36 and
an integral score of 4.29 to be superior to a MIP score of 3.00. In selected
cases, 3-D presurgical planning, prior to tumor resection, was clinically useful.
CONCLUSION: Integral and shell-MIP are useful 3-D display algorithms for
simultaneous display of superficial cerebral veins and gyri on MR images and of
thrombosis on CT venograms.
PMID- 9763388
TI - Iatrogenically induced cortical blindness associated with leptomeningeal
enhancement.
AB - Leptomeningeal enhancement is usually infective or neoplastic in origin. We
present a case in which a patient received total parenteral nutrition via a
catheter unknowingly placed within the right vertebral artery. We postulate that
the hyperosmolar nature of the infused solution induced temporary osmotic
disruption of the blood-brain barrier, resulting in cortical blindness associated
with localized leptomeningeal enhancement.
PMID- 9763389
TI - Follow-up study after intracranial percutaneous transluminal cerebral balloon
angioplasty.
AB - BACKGROUND AND PURPOSE: Our objective was to find the specific angiographic
characteristics of atherosclerotic lesions that indicate suitability for
intracranial percutaneous transluminal cerebral balloon angioplasty (PTCBA).
METHODS: Forty-two clinically symptomatic patients with 42 hemodynamically
significant intracranial lesions (>70% stenosis) were treated by PTCBA between
January 1992 and May 1996. Before treatment, the patients were assigned to three
groups according to the angiographic characteristics of the lesions, as follows:
type A, short (5 mm or less in length) concentric or moderately eccentric lesions
less than totally occlusive; type B, tubular (5 to 10 mm in length), extremely
eccentric or totally occluded lesions, less than 3 months old; and type C,
diffuse (more than 10 mm in length), extremely angulated (>90 degrees) lesions
with excessive tortuosity of the proximal segment, or totally occluded lesions,
and 3 months old or older. The patients were followed up for a period of 1 month
to 6 years to compare the results of PTCBA treatment among the three groups.
Primary end points were death, stroke, or bypass surgery. RESULTS: The clinical
success rates for the type A, B, and C groups were 92%, 86%, and 33%,
respectively. Cumulative risks of fatal or nonfatal ischemic stroke or
ipsilateral bypass surgery in type A, B, and C groups were 8%, 26%, and 87%,
respectively. The cumulative risk of 8% among patients in the type A group
appeared to be smaller than in studies reported in the literature. CONCLUSION:
PTCBA for intracranial simple (type A) lesions yields a favorable clinical
outcome for symptomatic patients.
PMID- 9763390
TI - Carotid artery balloon angioplasty and stenting (CABAS): a neuroradiologic
perspective.
PMID- 9763391
TI - Thromboembolic events associated with the treatment of cerebral aneurysms with
Guglielmi detachable coils.
AB - BACKGROUND AND PURPOSE: The purpose of this study was to document the prevalence,
radiologic appearance, and treatment of thromboembolic events related to GDC
embolization of cerebral aneurysms. METHODS: The clinical and radiologic records
of all patients undergoing GDC treatment of intracranial aneurysms at our
institution were reviewed. All cases in which unexpected complications occurred
were selected. Those complications related to presumed thromboembolic events were
analyzed. RESULTS: Of 59 patients (60 aneurysms) treated with GDCs, 17 (28%)
experienced thromboembolic events. Seven patients had transient ischemic attacks
and 10 had strokes. In 10 patients, the deficits occurred during or immediately
after the procedure; in the rest, the complications were delayed. In six
patients, all radiologic investigations were negative for infarction and in seven
patients, CT scans showed new ischemic lesions. In four patients, MR imaging
alone showed infarcts, and in four of nine patients who underwent subsequent
angiography, acute ischemic findings were demonstrated. Eight patients were
treated with volume expansion, eight with full heparinization, and one patient
underwent intraarterial thrombolysis. Clinical outcome was excellent or good in
14 of 17 patients, with only three patients (5%) incurring permanent neurologic
deficits. CONCLUSION: Thromboembolic events related to GDC treatment may be more
common than has been reported in the literature. In our experience, this rate was
28%, with persisting deficits in 5%. These events can occur after uncomplicated
procedures and may be unaccompanied by radiologic findings. Clinical outcome is
usually favorable.
PMID- 9763393
TI - Endovascular treatment of basilar tip aneurysms after direct puncture of the
vertebral artery.
AB - Basilar aneurysms that are not amenable to standard endovascular treatment via
the femoral approach because catheterization is difficult pose a rare but serious
problem. We present two cases of basilar tip aneurysms successfully treated by
the endovascular route after direct puncture of the right vertebral artery. In
both patients, the left vertebral artery was tortuous, small, and irregular, and
the ostium of the right vertebral artery was not accessible by the femoral
approach.
PMID- 9763392
TI - Transcranial Doppler sonographic monitoring during cerebral aneurysm
embolization: a preliminary report.
AB - BACKGROUND AND PURPOSE: The wide application of embolization in the treatment of
aneurysms has created the need for an intraprocedural means to anticipate a poor
outcome by monitoring hemodynamic changes in the brain. METHODS: Transcranial
Doppler sonography was used to monitor flow velocity in the middle cerebral
artery (MCA) in 23 patients undergoing embolization with Guglielmi detachable
coils (GDCs) of either incidental or symptomatic intracranial aneurysms.
Sonographic values were recorded from the ipsilateral MCA at the beginning,
middle, and end of the interventional procedure and 24 hours afterward. RESULTS:
No complications occurred in 15 patients. In these cases, sonography showed an
average decrease in MCA flow velocity of 2.7% after GDC application, returning to
baseline at the end of treatment and then increasing by about 17% 24 hours later.
In four patients with vasospasm on posttreatment angiograms, MCA flow velocity
increased to values higher than 120 cm/s after GDC application, returning to
baseline after 24 hours. In four patients with ischemic complications (two
transient ischemic attacks, one stroke, one vascular death), MCA flow velocity
decreased more than 30% and did not return to preoperative values within 24
hours. CONCLUSION: The application of transcranial Doppler sonographic monitoring
during endovascular treatment may help to identify patients at risk for
posttreatment cerebral ischemia.
PMID- 9763394
TI - Collateral circulation and outcome after basilar artery thrombolysis.
AB - BACKGROUND AND PURPOSE: This study was undertaken to examine the relationship
between collateral flow and outcome after local intraarterial thrombolytic
treatment for basilar artery thrombosis. METHODS: Twenty-four patients with
symptomatic basilar thrombosis were treated with intraarterial urokinase.
Angiograms at the time of treatment were analyzed to characterize collateral
flow. The number of posterior communicating arteries (PCoAs) and the degree of
collateral filling of the basilar artery were then compared with symptom duration
before treatment, with Glasgow Coma Scale (GCS) score at the time of treatment,
with 90-day modified Rankin score, and with 90-day survival status. RESULTS: Of
the 20 patients who had carotid artery injections at the time of the thrombolytic
procedure, two had no PCoA, eight had one PCoA, and 10 had two PCoAs. Nine had no
collateral opacification of the basilar artery, six had collateral opacification
of the distal basilar artery, and five had collateral opacification of the distal
and proximal basilar artery. Ninety-day survival was 38%; 25% of patients had
good neurologic outcomes. No correlation was found between the number of PCoAs
and symptom duration, pretreatment GCS score, survival, or neurologic outcome.
Duration of symptoms before treatment was longer in patients with collateral flow
to the basilar artery. Basilar artery collateral flow did not correlate with
survival, but it did correlate with neurologic outcome for the 12 patients with
middle or distal basilar artery thrombus in whom collateral flow to the basilar
artery was assessed (83% with collateral flow had good neurologic outcomes, but
only 17% without collateral flow had good outcomes). All six patients with
proximal basilar artery thrombus in whom collateral flow was assessed died,
independent of the collateral flow observed. CONCLUSION: In symptomatic acute
basilar artery thrombosis, neurologic outcome was better after intraarterial
thrombolysis in patients who had collateral filling of the basilar artery, except
in cases of proximal basilar thrombosis. Patients with collateral filling of the
basilar artery also tolerated longer symptom duration.
PMID- 9763395
TI - The use of electrolytically detachable coils in treating high-flow arteriovenous
fistulas.
AB - BACKGROUND AND PURPOSE: High-flow arteriovenous fistulas (AVFs) are commonly
treated by using an endovascular approach with a variety of materials. The use of
a Guglielmi electrolytically detachable coil (GDC) provides the ability to
reposition or remove the coil if its position is not optimal and may minimize the
risk of coil migration or distal embolization. This study reports our experience
in using these coils alone or in combination with other materials in the
treatment of intracranial and cervical high-flow fistulas. METHODS: Twelve
patients with AVFs were treated with GDCs via the transvenous or transarterial
transfistulous routes. The six dural AVFs treated transvenously were also treated
transarterially, and the GDCs were combined with fibered coils in three of these
patients and in two other patients with pial AVFs. All patients have been
clinically followed up for 12 to 48 months (mean, 28 months). RESULTS:
Angiographic obliteration was obtained in all 12 patients. The fistulas have
remained closed in 11 patients, as ascertained by angiographic confirmation in
two patients and by clinical examination in nine patients. The one patient with
recurrence experienced neurologic improvement and refused further treatment. GDCs
required repositioning before detachment in seven patients, and no migration
occurred after detachment. CONCLUSION: GDCs are useful for the treatment of high
flow AVFs. They afford more control in the placement of coils and may provide an
anchoring point for more thrombogenic materials.
PMID- 9763396
TI - Performance characteristics of microcatheter systems in a standardized tortuous
pathway.
AB - BACKGROUND AND PURPOSE: Published reports of controlled experiments designed to
evaluate the performance of over-the-wire microcatheter systems are rare and have
often been based on subjective impressions from small clinical series. This
investigation was designed to compare the load forces required to propel state-of
the-art, hydrophilically coated microcatheters from each of four manufacturers
through a standardized tortuous pathway constructed of polytetrafluoroethylene
tubing. METHODS: Currently available hydrophilically coated microcatheters were
provided by four manufacturers. A 20-cm long, three-dimensional pathway
simulating the intracranial carotid circulation was constructed of 0.065-in.
(inner diameter) polytetrafluoroethylene tubing and immersed in a water bath at
37 degrees C. Testing was performed using an Instron tabletop load frame fitted
with a 2-lb load cell. Durability and load force tests were conducted using a
0.014-in. stainless steel noncoated guidewire, with the wire tip protruding 1 cm
beyond the catheter tip. At least four samples of microcatheters from each
manufacturer were tested. RESULTS: Extensive trackability testing of the
guidewire alone established reproducible performance with maximum load forces of
less than 8 g. Maximum gram forces for the four reinforced microcatheters were
not greatly different, measuring between 9 and 14 g. Excessive buckling of the
only nonreinforced catheter was initially overcome early in the pathway in a
staccato, stepwise fashion. After reaching a critical load, however, the catheter
and guidewire prolapsed. CONCLUSION: All reinforced microcatheters tested
established good and reproducible performance in our model. Reinforced
microcatheters provided superior trackability over the one nonreinforced device
tested.
PMID- 9763397
TI - Presumed venous infarction in spinal decompression sickness.
AB - We describe the serial MR imaging findings in a patient with spinal decompression
sickness. In the acute phase, the spinal cord was swollen, with increased T2
signal in the posterior part of the column; 1 month later, marked contrast
enhancement was noted in the same location; and 2 months later, the swelling and
T2 signal had decreased. MR imaging may facilitate the early diagnosis of spinal
decompression sickness.
PMID- 9763398
TI - Comparison of in vivo and in vitro deposition of rhodamine and fluorescein in
hair.
AB - A direct differentiation of the internal and external drug-deposition pattern
into hair was made using two fluorescent dyes and fluorescence microscopy after
systemic administration to mice or external exposure of untreated hair. Mice (23
days old, C57 and Balb/C) were administered either rhodamine or fluorescein
intraperitoneally at varied doses on 3 consecutive days of 3 weeks, and hair was
sampled 1 week later. Another group was given 10 mg/kg rhodamine or 100 mg/kg
fluorescein and sampled at time points from 5 min to 168 hr. The time courses of
external deposition of rhodamine and fluorescein into untreated hair were
examined after hair was soaked in 0.1 mg/ml solutions at pH 3, pH 6, and pH 9
aqueous buffer or methanol. The hair was then extracted in pH 6 phosphate buffer
or methanol for 24 hr. In vivo accumulation was distinguishable as fluorescent
bands along the length of the hair for rhodamine and fluorescein. The pattern of
in vivo deposition appears to arise from the rapid accumulation within the cortex
and medulla, with little deposition evident in the cuticle. Neither phosphate
buffer nor methanol washes affected the intensity of fluorescence in the hair.
External loading of rhodamine into the hair resulted in staining of the junctions
of cuticle scales. This pattern persisted even after 12 hr of solution exposure.
Extraction with pH 6 phosphate buffer or methanol did not remove rhodamine.
Fluoroscein followed a similar pattern, with maximum fluorescence when hair was
loaded in pH 6 100mM phosphate buffer and nominal staining when loaded in pH 9
100 mM Tris buffer or methanol. Soaking the hair in pH 6 buffer, but not
methanol, removed some fluorescein. These results demonstrate that compounds in
the circulation can rapidly diffuse into the forming cortex and medulla, where
rapid associations occur with elongating intermediate filaments specific to the
medulla and cortex. These compounds can become significantly occluded within the
mature matrix and are resistant to removal in aqueous or methanolic solutions.
PMID- 9763399
TI - Disposition of L-732,531, a potent immunosuppressant, in rats and baboons.
AB - L-732,531 is a semi-synthetic analog of the macrolide tacrolimus (Prograf(R)).
Like tacrolimus, L-732,531 is a potent immunosuppressant. In this study, its
absorption, distribution, metabolism, and excretion were studied in rats and
baboons. In rats, its blood and plasma levels were similar, whereas in baboons,
its blood levels were, on average, twice as high as those in plasma. This was
consistent with the in vitro blood-to-plasma ratio of L-732, 531, which in these
two species, as well as in humans, was much lower than that of tacrolimus and
showed a minimal concentration dependence. After iv administration to rats, the
blood and plasma clearance of L-732,531 decreased from approximately 60 ml/min/kg
at 0.2 mg/kg to 30 ml/min/kg when dosed at 1 and 3 mg/kg. After oral
administration, plasma area under the concentration vs. time curve (AUC) and
maximal plasma concentration (Cmax) increased more than proportionally to the
dose. At 1, 5, and 15 mg/kg, plasma AUC was 29, 466, and 2832 ng.hr/ml,
respectively, and Cmax was 10, 129, and 304 ng/ml, respectively. Bioavailability,
although compromised by nonlinear kinetics, was estimated to be between 8% and
18%. In baboons, the clearance of L-732,531 was lower than that in rats,
especially when calculated from blood concentrations (12 ml/min/kg at 0.2 mg/kg
and 8 ml/min/kg at 1 mg/kg). After oral dosing, baboon plasma AUC and Cmax were
much lower than those in rats, but as in rats, they increased more than
proportionally with increasing doses. The bioavailability of L-732,531 in baboons
was estimated at 3%, 9%, and 24% when animals were dosed at 5, 15, and 26 mg/kg
po, respectively. After oral administration of [3H]L-732,531 at 5 mg/kg,
approximately 32% of the radioactivity was recovered in bile and urine of rats,
compared with 9% in baboons. High-performance liquid chromatography profiles of
rat and baboon plasma, bile, urine, and feces indicated that L-732,531 was
metabolized extensively to a complex mixture of products. Some intact parent drug
was observed in feces of orally dosed animals, indicating incomplete absorption.
In vitro, L-732,531 was metabolized more extensively by baboon liver microsomes
than rat or human microsomes. Its metabolism in human liver microsomes was shown
to be catalyzed primarily by cytochrome P450 3A isozymes.
PMID- 9763401
TI - Identification of the human liver cytochrome P450 enzymes involved in the in
vitro metabolism of a novel 5-lipoxygenase inhibitor.
AB - In vitro studies were conducted to identify the hepatic cytochrome P450 (CYP)
forms involved in the oxidative metabolism of [14C]ABT-761 and its N
dehydroxylated metabolite, [14C]ABT-438, by human liver microsomes. The two
compounds were metabolized by parallel pathways, to form the corresponding
methylene bridge hydroxy metabolites. There was no evidence of sulfoxidation
and/or ring hydroxylation. Over the ABT-761 and ABT-438 concentration ranges
studied (1-300 microM), the rate of NADPH-dependent hydroxylation was linear with
respect to substrate concentration ([S]) and did not conform to saturable
Michaelis-Menten kinetics. Under these conditions ([S] < KM), the intrinsic
clearance (Vmax/KM) of ABT-438 was 10-fold higher than that of ABT-761 (1.7 +/-
0.8 vs. 0.17 +/- 0.06 microl/min/mg, mean +/- SD, N = 3 livers). The
hydroxylation of both compounds was shown to be highly correlated (r = 0.83, p <
0.01, N = 11 different human livers) with CYP3A-selective erythromycin N
demethylase activity, and the correlation between ABT-761 hydroxylation and
tolbutamide hydroxylase (CYP2C9-selective) activity (r = 0.63, p < 0.05, N = 10)
was also statistically significant. Ketoconazole (2.0 microM), a CYP3A-selective
inhibitor, inhibited the hydroxylation of both compounds by 53-67%, and
sulfaphenazole (CYP2C9-selective) decreased activity by 10-20%. By comparison,
alpha-naphthoflavone, a known activator of CYP3A, stimulated the hydroxylation of
ABT-761 (8-fold) and ABT-438 (4-fold). In addition, the abundance-normalized
rates of cDNA-expressed CYP-dependent metabolism indicated that hydroxylation was
largely mediated (66-86%) by CYP3A(4). Therefore, it is concluded that the
hydroxylation of ABT-761 and ABT-438 (=10 microM) is primarily mediated by
CYP3A, although CYP2C9 may play an ancillary role.
PMID- 9763400
TI - Metabolism of carvedilol in dogs, rats, and mice.
AB - The excretion and biotransformation of carvedilol [1-[carbazolyl-(4)-oxy]-3-[(2
methoxyphenoxyethyl)amino]-2-p ropanol], a new, multiple-action, neurohormonal
antagonist that exhibits the combined pharmacological activities of beta
adrenoreceptor antagonism, vasodilation, and antioxidation, were investigated in
dogs, rats, and mice. Carvedilol was absorbed well, and biliary secretion was
predominant in each species. Carvedilol was metabolized extensively in each
species, and elimination of unchanged compound was minor in bile duct
catheterized rats and dogs. In dogs, glucuronidation of the parent compound and
hydroxylation of the carbazolyl ring, with subsequent glucuronidation, were the
major metabolic pathways. Rats showed the simplest metabolite profile; the
primary metabolites were formed by hydroxylation of the carbazolyl ring, with
subsequent glucuronidation. Mice displayed the most complicated metabolite
profile; glucuronidation of the parent compound and hydroxylation of either the
carbazolyl or phenyl ring, with subsequent glucuronidation, were the major
metabolic routes. O-Dealkylation was a minor pathway in all species examined.
PMID- 9763402
TI - Biodistribution and clearance of 125I-labeled C-reactive protein and 125I-labeled
modified C-reactive protein in CD-1 mice.
AB - Iodinated forms of C-reactive protein (CRP), soluble modified CRP (mCRP-sol), and
suspended mCRP (mCRP-susp) were injected iv into CD-1 mice, for analysis of their
pharmacokinetics (PK) and biodistribution (BD). The plasma half-life of 125I-CRP,
measured as 4.7 hr, agrees closely with previous reports. The PK and BD
characteristics for 125I-mCRP-sol and 125I-mCRP-susp were comparable to each
other and were distinctly different from those measured for CRP. Whereas
approximately 50% of 125I-CRP was recoverable from plasma 5 min after injection,
only approximately 5% of 125I-mCRP was similarly recoverable. The estimated
volume of distribution at steady state calculated for either form of 125I-mCRP
was approximately 10-fold greater than that calculated for 125I-CRP (23. 4-27.6
and 2.4 ml, respectively). The estimated mean residence times for 125I-mCRP were
approximately 2 times longer than that measured for 125I-CRP (9.5-11.5 hr,
compared with 4.9 hr). At both 4- and 24-hr time points, substantial amounts of
125I-mCRP were selectively distributed in the bone marrow. At 24 hr,
approximately 25% of the injected 125I-mCRP-sol and 125I-mCRP-susp was localized
to the bone marrow (corresponding to 92% of injected dose/g of tissue). At this
time point, only 8% (or 27%/g) of 125I-CRP was localized to the bone marrow.
Overall, the data presented indicate that 1) mCRP has PK and BD characteristics
distinct from those of CRP; 2) injected mCRP, although it is rapidly cleared from
the general circulation, accesses large body areas and is selectively localized
to the bone marrow; and 3) all forms of CRP appear to be excreted in the urine.
PMID- 9763403
TI - Disposition of the antipsychotic agent CI-1007 in rats, monkeys, dogs, and human
cytochrome P450 2D6 extensive metabolizers. Species comparison and allometric
scaling.
AB - The disposition of CI-1007 (I), an antipsychotic dopamine agonist, was studied
after iv or po administration to rats, monkeys, and dogs and po administration to
human cytochrome P450 2D6 extensive metabolizers (EMs). I was extensively
metabolized after po administration, with high hepatic clearance (CL) values and
negligible urinary excretion. Values for systemic plasma CL (28-40 ml/min/kg)
suggested hepatic plasma flow-limited CL. The oral CL of I was similar among the
species. Strong correlation was achieved in interspecies scaling for CL. After
oral administration of [14C]I, the major route of 14C elimination in rats was in
the bile (64%), followed by feces (29%) and urine (3.2%). Fecal excretion (64%)
was the major route of 14C elimination in monkeys, followed by urine (14%). Three
hydroxy metabolites, i.e. PD 147693 (II), PD 149394 (III), and PD 155144 (IV),
and two sulfates, i.e. PD 163637 (VI) and PD 163639 (VIII), were identified in
monkey plasma, urine, or feces. VIII was the major metabolite excreted in monkey
urine, and VI was the major component in feces. Trace amounts of II, VI, and VIII
were detected in the plasma and urine of human EMs but not in rats or dogs. II is
an active metabolite that was present in all species. After oral administration,
observed maximal plasma concentration and AUC values for II were higher than the
corresponding values for I in dog plasma, approximately 20-40% of the values for
I in monkeys and human EMs, and <5% of the values for I in rat plasma. Although
the metabolic profiles differ among species, strong correlation was achieved in
allometric scaling because the elimination of I from the body is mainly limited
by hepatic blood flow.
PMID- 9763404
TI - Comparative inhibition of human cytochromes P450 1A1 and 1A2 by flavonoids.
AB - Flavonoids are a class of dietary phytochemicals that modulate various biological
activities. The effects of flavone and five hydroxylated derivatives on the
methoxyresorufin O-demethylase activity catalyzed by cDNA-expressed human
cytochromes P450 (CYP)1A1 and 1A2 were examined. Flavone was a less potent
inhibitor of CYP1A1 (IC50 = 0.14 microM) than CYP1A2 (IC50 = 0.066 microM). Four
hydroxylated flavone derivatives (3-hydroxy-, 5-hydroxy-, 7-hydroxy-, and 3,7
dihydroxyflavone) were also potent inhibitors of CYP1A1 (IC50 < 0.1 microM) and
CYP1A2 (IC50 < 0.3 microM). For CYP1A1, 7-hydroxyflavone exhibited a competitive
mode of inhibition, with a Ki value of 0.015 microM and 6-fold selectivity for
CYP1A1 over CYP1A2. 3,5,7-Trihydroxyflavone (galangin) showed the highest potency
toward CYP1A2. The inhibition by galangin of the methoxyresorufin O-demethylase
activity of CYP1A2 was mixed-type, with a Ki value of 0.008 microM. Galangin
showed 5-fold selectivity in its inhibition of CYP1A2 over CYP1A1. The results
indicate that some flavonoids have high potencies and selectivities for
inhibition of CYP1A isozymes. This may have important implications for cancer
prevention, as well as other pharmacological and toxicological effects of these
compounds.
PMID- 9763405
TI - Metabolism of alpha-phosphonosulfonate squalene synthase inhibitors. I.
Disposition of a farnesylethyl alpha-phosphonosulfonate and ester prodrugs in
rats.
AB - The disposition of I [(E,E)-6,10,14-trimethyl-1-phosphono-5,9, 13-pentadecatriene
1-sulfonic acid] and its mono- (II), di- (III), and triester (IV) prodrugs in
rats was studied with 14C-labeled compounds. After iv administration of I (15
micromol/kg), radioactivity in plasma was measurable up to 96 hr and averaged 0.
026 microg-eq/ml. I accounted for >50% of the radioactivity in plasma and had an
apparent half-life of 4 hr. After oral administration of the same dose, the
maximal plasma concentration of radioactivity averaged 0.108 microg-eq/ml at 6
hr. In 96 hr, 19 and 73% of the iv dose and 2 and 97% of the po dose was excreted
in urine and feces, respectively. The absorption was 2.4%, based on the plasma
data. In 12 hr after an iv dose of I to bile duct-cannulated rats, 41 and 14% of
the dose was excreted in bile and urine, respectively. I accounted for 51% of the
radioactivity in bile and a negligible amount in urine. At 12 hr after iv dosing,
liver retained 31% of the dose. No accumulation of radioactivity in bone was
observed. I (3%) and II (6%) were poorly absorbed. Enhanced absorption was
observed for III (80%) and IV (45%). No I or metabolites of I were found in bile
or urine of rats dosed with the prodrugs. The structures of two metabolites each
for I, III, and IV were proposed. Together, they accounted for >80% of the
radioactivity in urine and approximately 50% of the radioactivity in bile for
each compound. Metabolism appeared to occur primarily at the farnesyl moiety,
presumably by the same pathways as for farnesyl-1-pyrophosphate.
PMID- 9763406
TI - Sulfhydryl-dependent biotransformation and macromolecular binding of 1,2-dibromo
2,4-dicyanobutane in blood.
AB - 1,2-Dibromo-2,4-dicyanobutane (BCB) is a broad-spectrum microbicide used
commercially in consumer products. The objectives of this study were to elucidate
the biotransformation of BCB, characterize its ability to covalently bind
macromolecules, and predict the possible toxicological ramifications of such
events. After iv administration of [14C]BCB to male Fischer 344 rats, 14C
equivalents were observed to bind gradually to blood constituents. By 48 hr,
approximately 12% of the total dose was covalently bound. At no time was parent
compound detected in the blood. However, the debrominated BCB metabolite 2
methyleneglutaronitrile (MGN) was observed. In vitro experiments revealed that
BCB was extremely labile and was readily debrominated in fresh whole blood,
erythrocyte preparations, and buffered glutathione (GSH) solutions. In each case,
the formation of MGN was inhibited by the alkylation of free sulfhydryls with N
ethylmaleimide (NEM). For every 1 mol of BCB converted to MGN, 2 mol of GSH were
oxidized to glutathione disulfide (GSSG) (BCB + 2 GSH --> MGN + GSSG + 2 HBr).
The oxidation of free sulfhydryls during the conversion of BCB to MGN caused
erythrocyte hemolysis (EC50 approximately 1 mM) in isolated preparations.
Hemolysis was increased by coincubation of BCB with NEM (EC50 approximately 0.3
mM) and was decreased by coincubation with GSH (EC50 > 3 mM). However, MGN did
not cause hemolysis of erythrocytes, even at concentrations 10-fold higher than
the EC50 of BCB. In vitro experiments also demonstrated that incubation with
either BCB or MGN resulted in significant macromolecular binding to the
erythrocyte fraction of the blood (approximately 80%). Incubation with NEM
resulted in a significant decrease in binding for both BCB (11.3% bound) and MGN
(29.5% bound). Because BCB is rapidly debrominated in whole blood, it appears
that MGN is the reactive species responsible for macromolecular binding. From
these studies, we conclude that the conversion of BCB to MGN is mediated by a
free sulfhydryl-dependent biotransformation pathway. Furthermore, BCB
biotransformation is required for erythrocyte binding, and the consumption of
free sulfhydryls associated with the biotransformation of BCB is responsible for
hemolysis.
PMID- 9763407
TI - Absorption, distribution, metabolism, and excretion of atevirdine in the rat.
AB - Atevirdine mesylate (U-87201E) is a highly specific nonnucleoside inhibitor of
human immunodeficiency virus type 1 reverse transcriptase. The absorption,
metabolism, and excretion of atevirdine were investigated in male and female
Sprague-Dawley rats after oral administration of nonradiolabeled atevirdine
mesylate at doses of 20 mg/kg/day or 200 mg/kg/day for 8 days, with
[14C]atevirdine mesylate single doses of 10 mg/kg or 100 mg/kg on study days 1
and 10. The distribution of [14C]atevirdine mesylate was also evaluated by whole
body autoradiography in male and female Sprague-Dawley, pregnant Sprague-Dawley,
and male Long-Evans rats after a single 10 mg/kg oral dose. Plasma levels of
atevirdine and its N-desethyl and O-desmethyl metabolites were determined by high
performance liquid chromatography (HPLC) with ultraviolet detection, urine and
feces were profiled for atevirdine and metabolites by HPLC with radiochemical
detection, major metabolites in urine were isolated and identified by nuclear
magnetic resonance and mass spectrometry, and minor urinary metabolites were
identified by liquid chromatography/mass spectrometry. Atevirdine was rapidly
absorbed. The pharmacokinetics of atevirdine were nonlinear. Gender differences
in the pharmacokinetics and metabolism of atevirdine were observed, consistent
with the involvement of cytochrome P450 3A. Atevirdine effectively crossed the
blood-brain barrier and had a high rate of maternal-fetal transfer. At the low
doses, <2% of the dose was excreted as unchanged parent drug, while atevirdine
constituted 9%-25% of the dose at the high doses. The metabolism of atevirdine
was extensive in the rat and involved N-deethylation, O-demethylation,
hydroxylation at the C-6 position of the indole ring, and hydroxylation of the
pyridine ring.
PMID- 9763408
TI - Uroporphyrinogen oxidation catalyzed by human cytochromes P450.
AB - Porphyria cutanea tarda is associated with excess hepatic production of
uroporphyrin. Oxidation of uroporphyrinogen to uroporphyrin was previously
demonstrated to be specifically catalyzed by cytochrome P450 (CYP) 1A2. Here, we
investigated the ability of human CYP1A2 to catalyze uroporphyrinogen oxidation
(UROX). UROX activity in human liver microsomes was maximally only 10% of the
activity in microsomes from livers of untreated mice. There was a poor
correlation of UROX activity with methoxyresorufin demethylation, an activity
catalyzed predominantly by CYP1A2 and strongly correlated with immunodetectable
CYP1A2. With CYP forms expressed in HepG2 cells, the methoxyresorufin
demethylation and (ethoxyresorufin deethylation) activities of murine and human
CYP1A2 forms were similar, but UROX activity catalyzed by human CYP1A2 was only
15-20% of the activity catalyzed by murine CYP1A2. Human CYP1A1, CYP1A2, and
CYP3A4 expressed in lymphoblastoid cells all catalyzed UROX. In insect cells,
CYP1A2 was more active in catalyzing UROX than was CYP1A1, CYP2E, CYP3A4, or
CYP3A5. Human CYP1A2 expressed in Escherichia coli as a fusion protein with rat
CYP oxidoreductase also catalyzed UROX. Reconstituted human CYP1A2 and CYP3A4
were active in catalyzing UROX, with reconstituted CYP1A2 having the highest
specific activity obtained in this study. From inhibitor studies, it was
concluded that some of the UROX activity in the insect cell microsomes was
attributable to expressed CYP and some to an unidentified source. These results
indicate that human CYP1A2 is active in catalyzing UROX but has lower activity
than the murine orthologue. The results also indicate that most of the UROX
activity found in human liver microsomes is not due to CYP1A2.
PMID- 9763409
TI - Catalytic properties of an expressed cytochrome P450 2B1 from a Wistar-Kyoto rat
liver cDNA library.
AB - Cytochrome P450 2B1 clones were isolated from a phenobarbital-induced Wistar
Kyoto (WKY) hepatic cDNA library and were found to contain a Glu-322 --> Val
substitution, compared with wild-type 2B1 from Sprague-Dawley rats. After
heterologous expression in Escherichia coli and purification, activities of this
2B1 E322V variant were determined for ethoxycoumarin and androstenedione. The
total activities and metabolite profiles did not differ between 2B1 E322V and
wild-type 2B1 for these substrates. In addition, similar rate constants of
inactivation were observed with the mechanism-based inactivators chloramphenicol,
N-(2-p-nitrophenethyl)chlorofluoroacetamide, and 9-ethynylphenanthrene. These
results suggest that the Glu-322 --> Val alteration in the 2B1 WKY variant does
not significantly affect 2B1 activity. However, another clone obtained from the
cDNA library contained two additional substitutions: Val-103 --> Ala and Glu-424
-> Lys. As residue 103 is within a predicted substrate recognition site (SRS-1),
it was of interest to determine whether the Val --> Ala substitution conferred
any unique catalytic activities on 2B1. No differences in the metabolism of
ethoxycoumarin or androstenedione were observed. However, the Val-103 --> Ala
alteration caused an approximately threefold decrease in the rate constant of
inactivation for 9-ethynylphenanthrene in comparison with either 2B1 E322V or
wild-type 2B1. Based on computer modeling, residue 103 is predicted to be near
the active site but at a distance greater than 5A from 9-ethynylphenanthrene. Our
results suggest that the Val-103 --> Ala alteration may have an indirect
influence on the susceptibility of P450 2B1 to mechanism-based inactivators.
PMID- 9763410
TI - Effect of androgen administration during puberty on hepatic CYP2C11, CYP3A, and
CYP2A1 expression in adult female rats.
AB - This biochemical and pharmacokinetic investigation was undertaken to evaluate the
effects of androgen administration during puberty on sex-dependent cytochrome
P450 (CYP or P450) enzyme expression in adult female rats. Hepatic testosterone
2alpha-hydroxylase activity and CYP2C11 and CYP3A protein levels were elevated in
prepubertally ovariectomized rats injected subcutaneously with testosterone
enanthate at 35-49 days of age and killed 41 days after discontinuation of
treatment. In contrast, testosterone 6beta- and 7alpha-hydroxylase activities and
CYP2A1 protein content were not affected. The increase in CYP2C11 and CYP3A was
likely not due to circulating testosterone because plasma testosterone was
undetectable. The calculated elimination half-life was 51 +/- 6 hr (mean +/- SE)
after testosterone enanthate administration. By 80 days after treatment, CYP2C11
and CYP3A levels were no longer increased. To determine if CYP2C11 expression was
responsive to a more periodic pattern of androgen release, ovariectomized rats
were injected subcutaneously once or twice daily with unesterified testosterone
(elimination half-life was 2.0 +/- 0.3 hr, mean +/- SE). Once- or twice-daily
dosing (5 or 2.5 micromol/kg/injection, respectively) during days 35-49 of age
did not increase the mean CYP2C11 expression in 90-day-old female rats, although
testosterone 2alpha-hydroxylase activity and CYP2C11 protein content were
elevated in three of the eight rats injected twice daily. Neither dosing regimen
increased CYP3A or decreased CYP2A1 expression. In summary, the results indicate
that treatment with testosterone enanthate during puberty resulted in a prolonged
but reversible increase in hepatic expression of CYP2C11 and CYP3A.
PMID- 9763411
TI - Immunohistochemical localization of UDP-glucuronosyltransferases in rat brain
during early development.
AB - Extrahepatic glucuronidation, such as that in the central nervous system (CNS),
may play a very important role in xenobiotic disposition and may serve to protect
the CNS from potentially toxic xenobiotics. UDP-glucuronosyltransferase (UGT) 1A6
is an important catalyst for phenol and polycyclic aromatic hydrocarbon
glucuronidation. Studies were designed to determine the immunohistochemical
localization of UGT1A6 and the steroid-reactive UGTs 2B2 and 2B3 in brain regions
throughout the rat development. Neuronal cells, such as pyramidal cells, in
sections from cerebral cortex and hippocampus displayed intensive UGT1A6-specific
staining. UGT1A6-specific staining was also found in neuronal cells throughout
the cerebral cortex, as well as in the cerebellar white matter. Glial cells
revealed no apparent staining. In addition, staining for UGT1A6 was seen in
choroid plexus at a later developmental stage. Although UGT1A6 staining was
evident, brain sections analyzed for UGT2B2 and UGT2B3 immunoreactivity showed no
significant staining. These results provide the first definitive evidence for the
presence and cellular localization of UGT1A6, in neurons of developing rat brain,
whereas UGT2B2 and UGT2B3 were not detected.
PMID- 9763413
TI - Major cytochrome P450 enzyme responsible for oxidation of secondary alcohols to
the corresponding ketones in mouse hepatic microsomes. Oxidation of 7-hydroxy
delta8-tetrahydrocannabinol to 7-oxo-delta8-tetrahydrocannabinol.
AB - The oxidative activities of 7alpha- and 7beta-hydroxy-Delta8-tetrahydrocannabinol
(7alpha- and 7beta-hydroxy-Delta8-THC) to 7-oxo-Delta8-THC in hepatic microsomes
of mice were significantly increased by the treatment of mice with dexamethasone
or phenobarbital. A cytochrome P450 enzyme, named P450MDX-B, was purified from
hepatic microsomes of dexamethasone-treated mice, and its apparent molecular mass
was estimated to be 51,000. The NH2-terminal amino acid sequence of P450MDX-B was
the same as that of CYP3A11. The oxidative activities of 7alpha- and 7beta
hydroxy-Delta8-THC were 2.55 and 4.92 nmol/min/nmol P450, respectively. The
antibody against P450MDX-B almost completely inhibited the oxidative activities
of 7alpha- and 7beta-hydroxy-Delta8-THC in mice. These results indicate that
P450MDX-B (CYP3A11) is a major enzyme responsible for the oxidation of 7alpha-
and 7beta-hydroxy-Delta8-THC to 7-oxo-Delta8-THC in mouse liver.
PMID- 9763412
TI - Regulation of hepatic cytochrome P450 2C11 by transforming growth factor-beta,
hepatocyte growth factor, and interleukin-11.
AB - Injection of rats with bacterial lipopolysaccharide down-regulates P450 (P450)
2C11 (2C11) mRNA to about 20% of its control levels after only 6 hr, and this
level is maintained for at least 48 hr. Although we and others have demonstrated
that this effect may be at least partially mediated by the cytokines interleukin
1, interleukin-6, and tumor necrosis factor-alpha, as well as by glucocorticoids,
the time courses and potencies of 2C11 repression by each single mediator
suggested that no cytokine alone is responsible for the entire time course of
2C11 suppression during inflammation. Here, we show that transforming growth
factor-beta, hepatocyte growth factor, and interleukin-11 are potent inhibitors
of 2C11 expression. In all three cases, 0.1 ng/ml was enough to down-regulate
2C11 mRNA levels to 50% of control. Interleukin-8, a cytokine that is secreted
during the acute phase response but does not influence the liver acute phase
response, did not affect 2C11 expression. The various mediators have different
time courses of 2C11 down-regulation, indicating that the roles of each may be
different at different phases of the response.
PMID- 9763414
TI - Human biotransformation of bropirimine. Characterization of the major bropirimine
oxidative metabolites formed in vitro.
AB - Bropirimine (2-amino-5-bromo-6-phenyl-4-pyrimidinone) is a member of a class of
antineoplastic agents known as aryl pyrimidinones. In human liver microsomal
incubations, bropirimine oxidative metabolism is characterized by the formation
of three metabolites. Mass spectrometric analysis of the incubation mixture
revealed three bropirimine oxidative metabolites, identified as the bropirimine
dihydrodiol, p-hydroxybropirimine, and m-hydroxybropirimine. In vitro studies
using human liver microsomes and recombinant cytochrome P450 isoforms were
performed to identify the P450 enzyme(s) responsible for bropirimine oxidation.
Coincubation with the selective CYP1A2 inhibitor alpha-naphthoflavone abolished
bropirimine metabolism in human liver microsomes. Furthermore, when screened
against a panel of cDNA expressed cytochrome P450 enzymes (CYP1A2, CYP2C9,
CYP2C19, CYP2D6, CYP2E1, and CYP3A4), bropirimine was metabolized to both p- and
m-hydroxybropirimine exclusively in incubations with cDNA-expressed CYP1A2
microsomes. Mechanistic studies using cDNA-expressed CYP1A2 microsomes fortified
with microsomal epoxide hydrolase revealed that all three bropirimine oxidative
metabolites appear to be the result of a common arene oxide, which serves as a
substrate for microsomal epoxide hydrolase to generate the dihydrodiol or
rearranges to yield p- and m-hydroxybropirimine.
PMID- 9763415
TI - Gene targeting studies begin to reveal the function of neurofilament proteins.
PMID- 9763416
TI - Transcription sites are not correlated with chromosome territories in wheat
nuclei.
AB - We have determined the relationship between overall nuclear architecture,
chromosome territories, and transcription sites within the nucleus, using three
dimensional confocal microscopy of well preserved tissue sections of wheat roots.
Chromosome territories were visualized by GISH using rye genomic probe in
wheat/rye translocation and addition lines. The chromosomes appeared as elongated
regions and showed a clear centromere-telomere polarization, with the two
visualized chromosomes lying approximately parallel to one another across the
nucleus. Labeling with probes to telomeres and centromeres confirmed a striking
Rabl configuration in all cells, with a clear clustering of the centromeres, and
cell files often maintained a common polarity through several division cycles.
Transcription sites were detected by BrUTP incorporation in unfixed tissue
sections and revealed a pattern of numerous foci uniformly distributed throughout
the nucleoplasm, as well as more intensely labeled foci in the nucleoli. It has
been suggested that the gene-rich regions in wheat chromosomes are clustered
towards the telomeres. However, we found no indication of a difference in
concentration of transcription sites between telomere and centromere poles of the
nucleus. Neither could we detect any evidence that the transcription sites were
preferentially localized with respect to the chromosome territorial boundaries.
PMID- 9763417
TI - Large-scale chromosomal movements during interphase progression in Drosophila.
AB - We examined the effect of cell cycle progression on various levels of chromosome
organization in Drosophila. Using bromodeoxyuridine incorporation and DNA
quantitation in combination with fluorescence in situ hybridization, we detected
gross chromosomal movements in diploid interphase nuclei of larvae. At the onset
of S-phase, an increased separation was seen between proximal and distal
positions of a long chromsome arm. Progression through S-phase disrupted
heterochromatic associations that have been correlated with gene silencing.
Additionally, we have found that large-scale G1 nuclear architecture is
continually dynamic. Nuclei display a Rabl configuration for only approximately 2
h after mitosis, and with further progression of G1-phase can establish
heterochromatic interactions between distal and proximal parts of the chromosome
arm. We also find evidence that somatic pairing of homologous chromosomes is
disrupted during S-phase more rapidly for a euchromatic than for a
heterochromatic region. Such interphase chromosome movements suggest a possible
mechanism that links gene regulation via nuclear positioning to the cell cycle:
delayed maturation of heterochromatin during G1-phase delays establishment of a
silent chromatin state.
PMID- 9763418
TI - Mutational analysis of the structure and localization of the nucleolus in the
yeast Saccharomyces cerevisiae.
AB - The nucleolus in Saccharomyces cerevisiae is a crescent-shaped structure that
makes extensive contact with the nuclear envelope. In different chromosomal rDNA
deletion mutants that we have analyzed, the nucleolus is not organized into a
crescent structure, as determined by immunofluorescence microscopy, fluorescence
in situ hybridization, and electron microscopy. A strain carrying a plasmid with
a single rDNA repeat transcribed by RNA polymerase I (Pol I) contained a
fragmented nucleolus distributed throughout the nucleus, primarily localized at
the nuclear periphery. A strain carrying a plasmid with the 35S rRNA coding
region fused to the GAL7 promoter and transcribed by Pol II contained a rounded
nucleolus that often lacked extensive contact with the nuclear envelope.
Ultrastructurally distinct domains were observed within the round nucleolus. A
similar rounded nucleolar morphology was also observed in strains carrying the
Pol I plasmid in combination with mutations that affect Pol I function. In a Pol
I-defective mutant strain that carried copies of the GAL7-35S rDNA fusion gene
integrated into the chromosomal rDNA locus, the nucleolus exhibited a round
morphology, but was more closely associated with the nuclear envelope in the form
of a bulge. Thus, both the organization of the rDNA genes and the type of
polymerase involved in rDNA expression strongly influence the organization and
localization of the nucleolus.
PMID- 9763419
TI - The perinucleolar compartment and transcription.
AB - The perinucleolar compartment (PNC) is a unique nuclear structure localized at
the periphery of the nucleolus. Several small RNAs transcribed by RNA polymerase
III and two hnRNP proteins have been localized in the PNC (Ghetti, A., S. Pinol
Roma, W.M. Michael, C. Morandi, and G. Dreyfuss. 1992. Nucleic Acids Res. 20:3671
3678; Matera, A.G., M.R. Frey, K. Margelot, and S.L. Wolin. 1995. J. Cell Biol.
129:1181- 1193; Timchenko, L.T., J.W. Miller, N.A. Timchenko, D.R. DeVore, K.V.
Datar, L. Lin, R. Roberts, C.T. Caskey, and M.S. Swanson. 1996. Nucleic Acids
Res. 24: 4407-4414; Huang, S., T. Deerinck, M.H. Ellisman, and D.L. Spector.
1997. J. Cell Biol. 137:965-974). In this report, we show that the PNC
incorporates Br-UTP and FITC-conjugated CTP within 5 min of pulse labeling.
Selective inhibition of RNA polymerase I does not appreciably affect the
nucleotide incorporation in the PNC. Inhibition of all RNA polymerases by
actinomycin D blocks the incorporation completely, suggesting that Br-UTP
incorporation in the PNC is due to transcription by RNA polymerases II and/or
III. Treatment of cells with an RNA polymerase II and III inhibitor induces a
significant reorganization of the PNC. In addition, double labeling experiments
showed that poly(A) RNA and some of the factors required for pre-mRNA processing
were localized in the PNC in addition to being distributed in their previously
characterized nucleoplasmic domains. Fluorescence recovery after photobleaching
(FRAP) analysis revealed a rapid turnover of polypyrimidine tract binding protein
within the PNC, demonstrating the dynamic nature of the structure. Together,
these findings suggest that the PNC is a functional compartment involved in RNA
metabolism in the cell nucleus.
PMID- 9763420
TI - Characterization of the kinetochore binding domain of CENP-E reveals interactions
with the kinetochore proteins CENP-F and hBUBR1.
AB - We have identified a 350-amino acid domain in the kinetochore motor CENP-E that
specifies kinetochore binding in mitosis but not during interphase. The
kinetochore binding domain was used in a yeast two-hybrid screen to isolate
interacting proteins that included the kinetochore proteins CENP-E, CENP-F, and
hBUBR1, a BUB1-related kinase that was found to be mutated in some colorectal
carcinomas (Cahill, D.P., C. Lengauer, J. Yu, G.J. Riggins, J.K. Wilson, S.D.
Markowitz, K.W. Kinzler, and B. Vogelstein. 1998. Nature. 392:300-303). CENP-F,
hBUBR1, and CENP-E assembled onto kinetochores in sequential order during late
stages of the cell cycle. These proteins therefore define discrete steps along
the kinetochore assembly pathway. Kinetochores of unaligned chromosome exhibited
stronger hBUBR1 and CENP-E staining than those of aligned chromosomes. CENP-E and
hBUBR1 remain colocalized at kinetochores until mid-anaphase when hBUBR1
localized to portions of the spindle midzone that did not overlap with CENP-E. As
CENP-E and hBUBR1 can coimmunoprecipitate with each other from HeLa cells, they
may function as a motor-kinase complex at kinetochores. However, the complex
distribution pattern of hBUBR1 suggests that it may regulate multiple functions
that include the kinetochore and the spindle midzone.
PMID- 9763421
TI - Fab1p is essential for PtdIns(3)P 5-kinase activity and the maintenance of
vacuolar size and membrane homeostasis.
AB - The Saccharomyces cerevisiae FAB1 gene encodes a 257-kD protein that contains a
cysteine-rich RING-FYVE domain at its NH2-terminus and a kinase domain at its
COOH terminus. Based on its sequence, Fab1p was initially proposed to function as
a phosphatidylinositol 4-phosphate (PtdIns(4)P) 5-kinase (). Additional sequence
analysis of the Fab1p kinase domain, reveals that Fab1p defines a subfamily of
putative PtdInsP kinases that is distinct from the kinases that synthesize
PtdIns(4,5)P2. Consistent with this, we find that unlike wild-type cells,
fab1Delta, fab1(tsf), and fab1 kinase domain point mutants lack detectable levels
of PtdIns(3,5)P2, a phosphoinositide recently identified both in yeast and
mammalian cells. PtdIns(4,5)P2 synthesis, on the other hand, is only moderately
affected even in fab1Delta mutants. The presence of PtdIns(3)P in fab1 mutants,
combined with previous data, indicate that PtdIns(3,5)P2 synthesis is a two step
process, requiring the production of PtdIns(3)P by the Vps34p PtdIns 3-kinase and
the subsequent Fab1p- dependent phosphorylation of PtdIns(3)P yielding
PtdIns(3,5)P2. Although Vps34p-mediated synthesis of PtdIns(3)P is required for
the proper sorting of hydrolases from the Golgi to the vacuole, the production of
PtdIns(3,5)P2 by Fab1p does not directly affect Golgi to vacuole trafficking,
suggesting that PtdIns(3,5)P2 has a distinct function. The major phenotypes
resulting from Fab1p kinase inactivation include temperature-sensitive growth,
vacuolar acidification defects, and dramatic increases in vacuolar size. Based on
our studies, we hypothesize that whereas Vps34p is essential for anterograde
trafficking of membrane and protein cargoes to the vacuole, Fab1p may play an
important compensatory role in the recycling/turnover of membranes deposited at
the vacuole. Interestingly, deletion of VAC7 also results in an enlarged vacuole
morphology and has no detectable PtdIns(3,5)P2, suggesting that Vac7p functions
as an upstream regulator, perhaps in a complex with Fab1p. We propose that Fab1p
and Vac7p are components of a signal transduction pathway which functions to
regulate the efflux or turnover of vacuolar membranes through the regulated
production of PtdIns(3,5)P2.
PMID- 9763422
TI - Sorting mechanisms regulating membrane protein traffic in the apical transcytotic
pathway of polarized MDCK cells.
AB - The transcytotic pathway followed by the polymeric IgA receptor (pIgR) carrying
its bound ligand (dIgA) from the basolateral to the apical surface of polarized
MDCK cells has been mapped using morphological tracers. At 20 degreesC dIgA-pIgR
internalize to interconnected groups of vacuoles and tubules that comprise the
endosomal compartment and in which they codistribute with internalized
transferrin receptors (TR) and epidermal growth factor receptors (EGFR). Upon
transfer to 37 degreesC the endosome vacuoles develop long tubules that give rise
to a distinctive population of 100-nm-diam cup-shaped vesicles containing pIgR.
At the same time, the endosome gives rise to multivesicular endosomes (MVB)
enriched in EGFR and to 60-nm-diam basolateral vesicles. The cup-shaped vesicles
carry the dIgA/pIgR complexes to the apical surface where they exocytose. Using
video microscopy and correlative electron microscopy to study cells grown thin
and flat we show that endosome vacuoles tubulate in response to dIgA/pIgR but
that the tubules contain TR as well as pIgR. However, we show that TR are removed
from these dIgA-induced tubules via clathrin-coated buds and, as a result, the
cup-shaped vesicles to which the tubules give rise become enriched in dIgA/pIgR.
Taken together with the published information available on pIgR trafficking
signals, our observations suggest that the steady-state concentrations of TR and
unoccupied pIgR on the basolateral surface of polarized MDCK cells are maintained
by a signal-dependent, clathrin-based sorting mechanism that operates along the
length of the transcytotic pathway. We propose that the differential sorting of
occupied receptors within the MDCK endosome is achieved by this clathrin-based
mechanism continuously retrieving receptors like TR from the pathways that
deliver pIgR to the apical surface and EGFR to the lysosome.
PMID- 9763423
TI - An atypical PKC directly associates and colocalizes at the epithelial tight
junction with ASIP, a mammalian homologue of Caenorhabditis elegans polarity
protein PAR-3.
AB - Cell polarity is fundamental to differentiation and function of most cells.
Studies in mammalian epithelial cells have revealed that the establishment and
maintenance of cell polarity depends upon cell adhesion, signaling networks, the
cytoskeleton, and protein transport. Atypical protein kinase C (PKC) isotypes
PKCzeta and PKClambda have been implicated in signaling through lipid metabolites
including phosphatidylinositol 3-phosphates, but their physiological role remains
elusive. In the present study we report the identification of a protein, ASIP
(atypical PKC isotype-specific interacting protein), that binds to aPKCs, and
show that it colocalizes with PKClambda to the cell junctional complex in
cultured epithelial MDCKII cells and rat intestinal epithelia. In addition,
immunoelectron microscopy revealed that ASIP localizes to tight junctions in
intestinal epithelial cells. Furthermore, ASIP shows significant sequence
similarity to Caenorhabditis elegans PAR-3. PAR-3 protein is localized to the
anterior periphery of the one-cell embryo, and is required for the establishment
of cell polarity in early embryos. ASIP and PAR-3 share three PDZ domains, and
can both bind to aPKCs. Taken together, our results suggest a role for a protein
complex containing ASIP and aPKC in the establishment and/or maintenance of
epithelial cell polarity. The evolutionary conservation of the protein complex
and its asymmetric distribution in polarized cells from worm embryo to mammalian
differentiated cells may mean that the complex functions generally in the
organization of cellular asymmetry.
PMID- 9763425
TI - Why are two different cross-linkers necessary for actin bundle formation in vivo
and what does each cross-link contribute?
AB - In developing Drosophila bristles two species of cross-linker, the forked
proteins and fascin, connect adjacent actin filaments into bundles. Bundles form
in three phases: (a) tiny bundles appear; (b) these bundles aggregate into larger
bundles; and (c) the filaments become maximally cross-linked by fascin. In
mutants that completely lack forked, aggregation of the bundles does not occur so
that the mature bundles consist of <50 filaments versus approximately 700 for
wild type. If the forked concentration is genetically reduced to half the wild
type, aggregation of the tiny bundles occurs but the filaments are poorly ordered
albeit with small patches of fascin cross-linked filaments. In mutants containing
an excess of forked, all the bundles tend to aggregate and the filaments are
maximally crossbridged by fascin. Alternatively, if fascin is absent, phases 1
and 2 occur normally but the resultant bundles are twisted and the filaments
within them are poorly ordered. By extracting fully elongated bristles with
potassium iodide which removes fascin but leaves forked, the bundles change from
being straight to twisted and the filaments within them become poorly ordered.
From these observations we conclude that (a) forked is used early in development
to aggregate the tiny bundles into larger bundles; and (b) forked facilitates
fascin entry into the bundles to maximally cross-link the actin filaments into
straight, compact, rigid bundles. Thus, forked aligns the filaments and then
directs fascin binding so that inappropriate cross-linking does not occur.
PMID- 9763424
TI - Small espin: a third actin-bundling protein and potential forked protein ortholog
in brush border microvilli.
AB - An approximately 30-kD isoform of the actin-binding/ bundling protein espin has
been discovered in the brush borders of absorptive epithelial cells in rat
intestine and kidney. Small espin is identical in sequence to the COOH terminus
of the larger ( approximately 110-kD) espin isoform identified in the actin
bundles of Sertoli cell-spermatid junctional plaques (Bartles, J.R., A. Wierda,
and L. Zheng. 1996. J. Cell Sci. 109:1229-1239), but it contains two unique
peptides at its NH2 terminus. Small espin was localized to the parallel actin
bundles of brush border microvilli, resisted extraction with Triton X-100, and
accumulated in the brush border during enterocyte differentiation/migration along
the crypt-villus axis in adults. In transfected BHK fibroblasts, green
fluorescent protein-small espin decorated F-actin-containing fibers and appeared
to elicit their accumulation and/or bundling. Recombinant small espin bound to
skeletal muscle and nonmuscle F-actin with high affinity (Kd = 150 and 50 nM) and
cross-linked the filaments into bundles. Sedimentation, gel filtration, and
circular dichroism analyses suggested that recombinant small espin was a monomer
with an asymmetrical shape and a high percentage of alpha-helix. Deletion
mutagenesis suggested that small espin contained two actin-binding sites in its
COOH-terminal 116-amino acid peptide and that the NH2-terminal half of its forked
homology peptide was necessary for bundling activity.
PMID- 9763426
TI - Clb5-associated kinase activity is required early in the spindle pathway for
correct preanaphase nuclear positioning in Saccharomyces cerevisiae.
AB - In Saccharomyces cerevisiae, a single cyclin-dependent kinase, Cdc28, regulates
both G1/S and G2/M phase transitions by associating with stage-specific cyclins.
During progression through S phase and G2/M, Cdc28 is activated by the B-type
cyclins Clb1-6. Because of functional redundancy, specific roles for individual
Clbs have been difficult to assign. To help genetically define such roles,
strains carrying a cdc28(ts) allele, combined with single CLB deletions were
studied. We assumed that by limiting the activity of the kinase, these strains
would be rendered more sensitive to loss of individual Clbs. By this approach, a
novel phenotype associated with CLB5 mutation was observed. Homozygous cdc28
4(ts) clb5 diploids were inviable at room temperature. Cells were defective in
spindle positioning, leading to migration of undivided nuclei into the bud.
Occasionally, misplaced spindles were observed in cdc28-4 clb5 haploids;
additional deletion of CLB6 caused full penetrance. Thus, CLB5 effects proper
preanaphase spindle positioning, yet the requirement differs in haploids and
diploids. The execution point for the defect corresponded to the time of Clb5
dependent kinase activation. Nevertheless, lethality of cdc28-4 clb5 diploids was
not rescued by CLB2 or CLB4 overexpression, indicating a specificity of Clb5
function beyond temporality of expression.
PMID- 9763427
TI - Motile properties of vimentin intermediate filament networks in living cells.
AB - The motile properties of intermediate filament (IF) networks have been studied in
living cells expressing vimentin tagged with green fluorescent protein (GFP
vimentin). In interphase and mitotic cells, GFP-vimentin is incorporated into the
endogenous IF network, and accurately reports the behavior of IF. Time-lapse
observations of interphase arrays of vimentin fibrils demonstrate that they are
constantly changing their configurations in the absence of alterations in cell
shape. Intersecting points of vimentin fibrils, or foci, frequently move towards
or away from each other, indicating that the fibrils can lengthen or shorten.
Fluorescence recovery after photobleaching shows that bleach zones across fibrils
rapidly recover their fluorescence. During this recovery, bleached zones
frequently move, indicating translocation of fibrils. Intriguingly, neighboring
fibrils within a cell can exhibit different rates and directions of movement, and
they often appear to extend or elongate into the peripheral regions of the
cytoplasm. In these same regions, short filamentous structures are also seen
actively translocating. All of these motile properties require energy, and the
majority appear to be mediated by interactions of IF with microtubules and
microfilaments.
PMID- 9763428
TI - Rapid movements of vimentin on microtubule tracks: kinesin-dependent assembly of
intermediate filament networks.
AB - The assembly and maintenance of an extended intermediate filament (IF) network in
fibroblasts requires microtubule (MT) integrity. Using a green fluorescent
protein-vimentin construct, and spreading BHK-21 cells as a model system to study
IF-MT interactions, we have discovered a novel mechanism involved in the assembly
of the vimentin IF cytoskeleton. This entails the rapid, discontinuous, and MT
dependent movement of IF precursors towards the peripheral regions of the
cytoplasm where they appear to assemble into short fibrils. These precursors, or
vimentin dots, move at speeds averaging 0.55 +/- 0.24 micrometer/s. The vimentin
dots colocalize with MT and their motility is inhibited after treatment with
nocodazole. Our studies further implicate a conventional kinesin in the movement
of the vimentin dots. The dots colocalize with conventional kinesin as shown by
indirect immunofluorescence, and IF preparations from spreading cells are
enriched in kinesin. Furthermore, microinjection of kinesin antibodies into
spreading cells prevents the assembly of an extended IF network. These studies
provide insights into the interactions between the IF and MT systems. They also
suggest a role for conventional kinesin in the distribution of non-membranous
protein cargo, and the local regulation of IF assembly.
PMID- 9763430
TI - Disruption of the NF-H gene increases axonal microtubule content and velocity of
neurofilament transport: relief of axonopathy resulting from the toxin beta,beta'
iminodipropionitrile.
AB - To investigate the role of the neurofilament heavy (NF-H) subunit in neuronal
function, we generated mice bearing a targeted disruption of the gene coding for
the NF-H subunit. Surprisingly, the lack of NF-H subunits had little effect on
axonal calibers and electron microscopy revealed no significant changes in the
number and packing density of neurofilaments made up of only the neurofilament
light (NF-L) and neurofilament medium (NF-M) subunits. However, our analysis of
NF-H knockout mice revealed an approximately 2.4-fold increase of microtubule
density in their large ventral root axons. This finding was further corroborated
by a corresponding increase in the ratio of assembled tubulin to NF-L protein in
insoluble cytoskeletal preparations from the sciatic nerve. Axonal transport
studies carried out by the injection of [35S]methionine into spinal cord revealed
an increased transport velocity of newly synthesized NF-L and NF-M proteins in
motor axons of NF-H knockout mice. When treated with beta,beta'
iminodipropionitrile (IDPN), a neurotoxin that segregates microtubules and
retards neurofilament transport, mice heterozygous or homozygous for the NF-H
null mutation did not develop neurofilamentous swellings in motor neurons, unlike
normal mouse littermates. These results indicate that the NF-H subunit is a key
mediator of IDPN-induced axonopathy.
PMID- 9763429
TI - Neurofilament-dependent radial growth of motor axons and axonal organization of
neurofilaments does not require the neurofilament heavy subunit (NF-H) or its
phosphorylation.
AB - Neurofilaments are essential for establishment and maintenance of axonal diameter
of large myelinated axons, a property that determines the velocity of electrical
signal conduction. One prominent model for how neurofilaments specify axonal
growth is that the 660-amino acid, heavily phosphorylated tail domain of
neurofilament heavy subunit (NF-H) is responsible for neurofilament-dependent
structuring of axoplasm through intra-axonal crossbridging between adjacent
neurofilaments or to other axonal structures. To test such a role, homologous
recombination was used to generate NF-H-null mice. In peripheral motor and
sensory axons, absence of NF-H does not significantly affect the number of
neurofilaments or axonal elongation or targeting, but it does affect the
efficiency of survival of motor and sensory axons. Loss of NF-H caused only a
slight reduction in nearest neighbor spacing of neurofilaments and did not affect
neurofilament distribution in either large- or small-diameter motor axons. Since
postnatal growth of motor axon caliber continues largely unabated in the absence
of NF-H, neither interactions mediated by NF-H nor the extensive phosphorylation
of it within myelinated axonal segments are essential features of this growth.
PMID- 9763431
TI - Requirement of heavy neurofilament subunit in the development of axons with large
calibers.
AB - Neurofilaments (NFs) are prominent components of large myelinated axons. Previous
studies have suggested that NF number as well as the phosphorylation state of the
COOH-terminal tail of the heavy neurofilament (NF-H) subunit are major
determinants of axonal caliber. We created NF-H knockout mice to assess the
contribution of NF-H to the development of axon size as well as its effect on the
amounts of low and mid-sized NF subunits (NF-L and NF-M respectively).
Surprisingly, we found that NF-L levels were reduced only slightly whereas NF-M
and tubulin proteins were unchanged in NF-H-null mice. However, the calibers of
both large and small diameter myelinated axons were diminished in NF-H-null mice
despite the fact that these mice showed only a slight decrease in NF density and
that filaments in the mutant were most frequently spaced at the same
interfilament distance found in control. Significantly, large diameter axons
failed to develop in both the central and peripheral nervous systems. These
results demonstrate directly that unlike losing the NF-L or NF-M subunits, loss
of NF-H has only a slight effect on NF number in axons. Yet NF-H plays a major
role in the development of large diameter axons.
PMID- 9763432
TI - Regulated targeting of BAX to mitochondria.
AB - The proapoptotic protein BAX contains a single predicted transmembrane domain at
its COOH terminus. In unstimulated cells, BAX is located in the cytosol and in
peripheral association with intracellular membranes including mitochondria, but
inserts into mitochondrial membranes after a death signal. This failure to insert
into mitochondrial membrane in the absence of a death signal correlates with
repression of the transmembrane signal-anchor function of BAX by the NH2-terminal
domain. Targeting can be instated by deleting the domain or by replacing the BAX
transmembrane segment with that of BCL-2. In stimulated cells, the contribution
of the NH2 terminus of BAX correlates with further exposure of this domain after
membrane insertion of the protein. The peptidyl caspase inhibitor zVAD-fmk partly
blocks the stimulated mitochondrial membrane insertion of BAX in vivo, which is
consistent with the ability of apoptotic cell extracts to support mitochondrial
targeting of BAX in vitro, dependent on activation of caspase(s). Taken together,
our results suggest that regulated targeting of BAX to mitochondria in response
to a death signal is mediated by discrete domains within the BAX polypeptide. The
contribution of one or more caspases may reflect an initiation and/or
amplification of this regulated targeting.
PMID- 9763433
TI - Bax-induced cytochrome C release from mitochondria is independent of the
permeability transition pore but highly dependent on Mg2+ ions.
AB - Bcl-2 family members either promote or repress programmed cell death. Bax, a
death-promoting member, is a pore-forming, mitochondria-associated protein whose
mechanism of action is still unknown. During apoptosis, cytochrome C is released
from the mitochondria into the cytosol where it binds to APAF-1, a mammalian
homologue of Ced-4, and participates in the activation of caspases. The release
of cytochrome C has been postulated to be a consequence of the opening of the
mitochondrial permeability transition pore (PTP). We now report that Bax is
sufficient to trigger the release of cytochrome C from isolated mitochondria.
This pathway is distinct from the previously described calcium-inducible,
cyclosporin A-sensitive PTP. Rather, the cytochrome C release induced by Bax is
facilitated by Mg2+ and cannot be blocked by PTP inhibitors. These results
strongly suggest the existence of two distinct mechanisms leading to cytochrome C
release: one stimulated by calcium and inhibited by cyclosporin A, the other Bax
dependent, Mg2+ sensitive but cyclosporin insensitive.
PMID- 9763434
TI - Transition from caspase-dependent to caspase-independent mechanisms at the onset
of apoptotic execution.
AB - We have compared cytoplasmic extracts from chicken DU249 cells at various stages
along the apoptotic pathway. Extracts from morphologically normal "committed
stage" cells induce apoptotic morphology and DNA cleavage in substrate nuclei but
require ongoing caspase activity to do so. In contrast, extracts from frankly
apoptotic cells induce apoptotic events in added nuclei in a caspase-independent
manner. Biochemical fractionation of these extracts reveals that a column
fraction enriched in endogenous active caspases is unable to induce DNA
fragmentation or chromatin condensation in substrate nuclei, whereas a caspase
depleted fraction induces both changes. Further characterization of the
"execution phase" extracts revealed the presence of an ICAD/DFF45 (inhibitor of
caspase-activated DNase/DNA fragmentation factor)- inhibitable nuclease
resembling CAD, plus another activity that was required for the apoptotic
chromatin condensation. Despite the presence of active caspases, committed stage
extracts lacked these downstream activities, suggesting that the caspases and
downstream factors are segregated from one another in vivo during the latent
phase. These observations not only indicate that caspases act in an executive
fashion, serving to activate downstream factors that disassemble the nucleus
rather than disassembling it themselves, but they also suggest that activation of
the downstream factors (rather than the caspases) is the critical event that
occurs at the transition from the latent to active phase of apoptosis.
PMID- 9763435
TI - Modulation of calcium current in arteriolar smooth muscle by alphav beta3 and
alpha5 beta1 integrin ligands.
AB - Vasoactive effects of soluble matrix proteins and integrin-binding peptides on
arterioles are mediated by alphav beta3 and alpha5 beta1 integrins. To examine
the underlying mechanisms, we measured L-type Ca2+ channel current in arteriolar
smooth muscle cells in response to integrin ligands. Whole-cell, inward Ba2+
currents were inhibited after application of soluble cyclic RGD peptide,
vitronectin (VN), fibronectin (FN), either of two anti-beta3 integrin antibodies,
or monovalent beta3 antibody. With VN or beta3 antibody coated onto microbeads
and presented as an insoluble ligand, current was also inhibited. In contrast,
beads coated with FN or alpha5 antibody produced significant enhancement of
current after bead attachment. Soluble alpha5 antibody had no effect on current
but blocked the increase in current evoked by FN-coated beads and enhanced
current when applied in combination with an appropriate IgG. The data suggest
that alphavbeta3 and alpha5 beta1 integrins are differentially linked through
intracellular signaling pathways to the L-type Ca2+ channel and thereby alter
control of Ca2+ influx in vascular smooth muscle. This would account for the
vasoactive effects of integrin ligands on arterioles and provide a potential
mechanism for wound recognition during tissue injury.
PMID- 9763436
TI - Cre-loxP-mediated inactivation of the alpha6A integrin splice variant in vivo:
evidence for a specific functional role of alpha6A in lymphocyte migration but
not in heart development.
AB - Two splice variants of the alpha6 integrin subunit, alpha6A and alpha6B, with
different cytoplasmic domains, have previously been described. While alpha6B is
expressed throughout the development of the mouse, the expression of alpha6A
begins at 8.5 days post coitum and is initially restricted to the myocardium.
Later in ontogeny, alpha6A is found in various epithelia and in certain cells of
the immune system. In this study, we have investigated the function of alpha6A in
vivo by generating knockout mice deficient for this splice variant. The Cre- loxP
system of the bacteriophage P1 was used to specifically remove the exon encoding
the cytoplasmic domain of alpha6A in embryonic stem cells, and the deletion
resulted in the expression of alpha6B in all tissues that normally express
alpha6A. We show that alpha6A-/- mice develop normally and are fertile. The
substitution of alpha6A by alpha6B does not impair the development and function
of the heart, hemidesmosome formation in the epidermis, or keratinocyte
migration. Furthermore, T cells differentiated normally in alpha6A-/- mice.
However, the substitution of alpha6A by alpha6B leads to a decrease in the
migration of lymphocytes through laminin-coated Transwell filters and to a
reduction of the number of T cells isolated from the peripheral and mesenteric
lymph nodes. Lymphocyte homing to the lymph nodes, which involves various types
of integrin-ligand interactions, was not affected in the alpha6A knockout mice,
indicating that the reduced number of lymph node cells could not be directly
attributed to defects in lymphocyte trafficking. Nevertheless, the expression of
alpha6A might be necessary for optimal lymphocyte migration on laminin in certain
pathological conditions.
PMID- 9763439
TI - Use of a beta1 integrin-deficient human T cell to identify beta1 integrin
cytoplasmic domain sequences critical for integrin function.
AB - T cell activation rapidly and transiently regulates the functional activity of
integrin receptors. Stimulation of CD3/T cell receptor, CD2 or CD28, as well as
activation with phorbol esters, can induce within minutes an increase in beta1
integrin-mediated adhesion of T cells to fibronectin. In this study, we have
produced and utilized a mutant of the Jurkat T cell line, designated A1, that
lacks protein and mRNA expression of the beta1 integrin subunit but retains
normal levels of CD2, CD3, and CD28 on the cell surface. Activation-dependent
adhesion of A1 cells to fibronectin could be restored upon transfection of a wild
type human beta1 integrin cDNA. Adhesion induced by phorbol 12-myristate 13
acetate-, CD3-, CD2-, and CD28 stimulation did not occur if the carboxy-terminal
five amino acids of the beta1 tail were truncated or if either of two well
conserved NPXY motifs were deleted. Scanning alanine substitutions of the carboxy
terminal five amino acids demonstrated a critical role for the tyrosine residue
at position 795. The carboxy-terminal truncation and the NPXY deletions also
reduced adhesion induced by direct stimulation of the beta1 integrin with the
activating beta1 integrin-specific mAb TS2/16, although the effects were not as
dramatic as observed with the other integrin-activating signals. These results
demonstrate a vital role for the amino-terminal NPXY motif and the carboxy
terminal end of the beta1 integrin cytoplasmic domain in activation-dependent
regulation of integrin-mediated adhesion in T cells. Furthermore, the A1 cell
line represents a valuable new cellular reagent for the analysis of beta1
integrin structure and function in human T cells.
PMID- 9763437
TI - Fibronectin matrix regulates activation of RHO and CDC42 GTPases and cell cycle
progression.
AB - Adherent cells assemble fibronectin into a fibrillar matrix on their apical
surface. The fibril formation is initiated by fibronectin binding to the
integrins alpha5 beta1 and alphav beta3, and is completed by a process that
includes fibronectin self-assembly. We found that a 76- amino acid fragment of
fibronectin (III1-C) that forms one of the self-assembly sites caused disassembly
of preformed fibronectin matrix without affecting cell adhesion. Treating
attached fibroblasts or endothelial cells with III1-C inhibited cell migration
and proliferation. Rho-dependent stress fiber formation and Rho-dependent focal
contact protein phosphorylation were also inhibited, whereas Cdc42 was activated,
leading to actin polymerization into filopodia. ACK (activated Cdc42-binding
kinase) and p38 MAPK (mitogen-activated protein kinase), two downstream effectors
of Cdc42, were activated, whereas PAK (p21-activated kinase) and JNK/SAPK (c-Jun
NH2-terminal kinase/ stress-activated protein kinase) were inhibited. III1-C
treatment also modulated activation of JNK and ERK (extracellular signal
regulated kinases) in response to growth factors, and reduced the activity of the
cyclin E-cdk2 complex. These results indicate that the absence of fibronectin
matrix causes activation of Cdc42, and that fibronectin matrix is required for
Rho activation and cell cycle progression.
PMID- 9763438
TI - In vitro reconstitution of microtubule plus end-directed, GTPgammaS-sensitive
motility of Golgi membranes.
AB - Purified Golgi membranes were mixed with cytosol and microtubules (MTs) and
observed by video enhanced light microscopy. Initially, the membranes appeared as
vesicles that moved along MTs. As time progressed, vesicles formed aggregates
from which membrane tubules emerged, traveled along MTs, and eventually generated
extensive reticular networks. Membrane motility required ATP, occurred mainly
toward MT plus ends, and was inhibited almost completely by the H1 monoclonal
antibody to kinesin heavy chain, 5'-adenylylimidodiphosphate, and 100 microM but
not 20 microM vanadate. Motility was also blocked by GTPgammaS or A1F4- but was
insensitive to A1C13, NaF, staurosporin, or okadaic acid. The targets for
GTPgammaS and A1F4- were evidently of cytosolic origin, did not include kinesin
or MTs, and were insensitive to several probes for trimeric G proteins. Transport
of Golgi membranes along MTs mediated by a kinesin has thus been reconstituted in
vitro. The motility is regulated by one or more cytosolic GTPases but not by
protein kinases or phosphatases that are inhibited by staurosporin or okadaic
acid, respectively. The pertinent GTPases are likely to be small G proteins or
possibly dynamin. The in vitro motility may correspond to Golgi-to-ER or Golgi-to
cell surface transport in vivo.
PMID- 9763441
TI - The role of topoisomerase II in meiotic chromosome condensation and segregation
in Schizosaccharomyces pombe.
AB - Topoisomerase II is able to break and rejoin double-strand DNA. It controls the
topological state and forms and resolves knots and catenanes. Not much is known
about the relation between the chromosome segregation and condensation defects as
found in yeast top2 mutants and the role of topoisomerase II in meiosis. We
studied meiosis in a heat-sensitive top2 mutant of Schizosaccharomyces pombe.
Topoisomerase II is not required until shortly before meiosis I. The enzyme is
necessary for condensation shortly before the first meiotic division but not for
early meiotic prophase condensation. DNA replication, prophase morphology, and
dynamics of the linear elements are normal in the top2 mutant. The top2 cells are
not able to perform meiosis I. Arrested cells have four spindle pole bodies and
two spindles but only one nucleus, suggesting that the arrest is nonregulatory.
Finally, we show that the arrest is partly solved in a top2 rec7 double mutant,
indicating that topoisomerase II functions in the segregation of recombined
chromosomes. We suggest that the inability to decatenate the replicated DNA is
the primary defect in top2. This leads to a loss of chromatin condensation
shortly before meiosis I, failure of sister chromatid separation, and a
nonregulatory arrest.
PMID- 9763440
TI - The role of glucosidase I (Cwh41p) in the biosynthesis of cell wall beta-1,6
glucan is indirect.
AB - CWH41, a gene involved in the assembly of cell wall beta-1,6-glucan, has recently
been shown to be the structural gene for Saccharomyces cerevisiae glucosidase I
that is responsible for initiating the trimming of terminal alpha-1,2-glucose
residue in the N-glycan processing pathway. To distinguish between a direct or
indirect role of Cwh41p in the biosynthesis of beta-1,6-glucan, we constructed a
double mutant, alg5Delta (lacking dolichol-P-glucose synthase) cwh41Delta, and
found that it has the same phenotype as the alg5Delta single mutant. It contains
wild-type levels of cell wall beta-1,6-glucan, shows moderate underglycosylation
of N-linked glycoproteins, and grows at concentrations of Calcofluor White (which
interferes with cell wall assembly) that are lethal to cwh41Delta single mutant.
The strong genetic interactions of CWH41 with KRE6 and KRE1, two other genes
involved in the beta-1,6-glucan biosynthetic pathway, disappear in the absence of
dolichol-P-glucose synthase (alg5Delta). The triple mutant
alg5Deltacwh41Deltakre6Delta is viable, whereas the double mutant
cwh41Deltakre6Delta in the same genetic background is not. The severe slow growth
phenotype and 75% reduction in cell wall beta-1,6-glucan, characteristic of the
cwh41Deltakre1Delta double mutant, are not observed in the triple mutant
alg5Deltacwh41Deltakre1Delta. Kre6p, a putative Golgi glucan synthase, is
unstable in cwh41Delta strains, and its overexpression renders these cells
Calcofluor White resistant. These results demonstrate that the role of
glucosidase I (Cwh41p) in the biosynthesis of cell wall beta-1,6-glucan is
indirect and that dolichol-P-glucose is not an intermediate in this pathway.
PMID- 9763443
TI - Ste6p mutants defective in exit from the endoplasmic reticulum (ER) reveal
aspects of an ER quality control pathway in Saccharomyces cerevisiae.
AB - We are studying the intracellular trafficking of the multispanning membrane
protein Ste6p, the a-factor transporter in Saccharomyces cerevisiae and a member
of the ATP-binding cassette superfamily of proteins. In the present study, we
have used Ste6p as model for studying the process of endoplasmic reticulum (ER)
quality control, about which relatively little is known in yeast. We have
identified three mutant forms of Ste6p that are aberrantly ER retained, as
determined by immunofluorescence and subcellular fractionation. By pulse-chase
metabolic labeling, we demonstrate that these mutants define two distinct
classes. The single member of Class I, Ste6-166p, is highly unstable. We show
that its degradation involves the ubiquitin-proteasome system, as indicated by
its in vivo stabilization in certain ubiquitin-proteasome mutants or when cells
are treated with the proteasome inhibitor drug MG132. The two Class II mutant
proteins, Ste6-13p and Ste6-90p, are hyperstable relative to wild-type Ste6p and
accumulate in the ER membrane. This represents the first report of a single
protein in yeast for which distinct mutant forms can be channeled to different
outcomes by the ER quality control system. We propose that these two classes of
ER-retained Ste6p mutants may define distinct checkpoint steps in a linear
pathway of ER quality control in yeast. In addition, a screen for high-copy
suppressors of the mating defect of one of the ER-retained ste6 mutants has
identified a proteasome subunit, Hrd2p/p97, previously implicated in the
regulated degradation of wild-type hydroxymethylglutaryl-CoA reductase in the ER
membrane.
PMID- 9763442
TI - Highly stoichiometric, stable, and specific association of integrin alpha3beta1
with CD151 provides a major link to phosphatidylinositol 4-kinase, and may
regulate cell migration.
AB - Here we describe an association between alpha3beta1 integrin and transmembrane-4
superfamily (TM4SF) protein CD151. This association is maintained in relatively
stringent detergents and thus is remarkably stable in comparison with previously
reported integrin-TM4SF protein associations. Also, the association is highly
specific (i.e., observed in vitro in absence of any other cell surface proteins),
and highly stoichiometric (nearly 90% of alpha3beta1 associated with CD151). In
addition, alpha3beta1 and CD151 appeared in parallel on many cell lines and
showed nearly identical skin staining patterns. Compared with other integrins,
alpha3beta1 exhibited a considerably higher level of associated
phosphatidylinositol-4-kinase (PtdIns 4-kinase) activity, most of which was
removed upon immunodepletion of CD151. Specificity for CD151 and PtdIns 4-kinase
association resided in the extracellular domain of alpha3beta1, thus establishing
a novel paradigm for the specific recruitment of an intracellular signaling
molecule. Finally, antibodies to either CD151 or alpha3beta1 caused a
approximately 88-92% reduction in neutrophil motility in response to f-Met-Leu
Phe on fibronectin, suggesting an functionally important role of these complexes
in cell migration.
PMID- 9763444
TI - Fibroblast growth factor (FGF) soluble receptor 1 acts as a natural inhibitor of
FGF2 neurotrophic activity during retinal degeneration.
AB - Fibroblast growth factors (FGF) 1 and 2 and their tyrosine kinase receptor (FGFR)
are present throughout the adult retina. FGFs are potential mitogens, but adult
retinal cells are maintained in a nonproliferative state unless the retina is
damaged. Our work aims to find a modulator of FGF signaling in normal and
pathological retina. We identified and sequenced a truncated FGFR1 form from rat
retina generated by the use of selective polyadenylation sites. This 70-kDa form
of soluble extracellular FGFR1 (SR1) was distributed mainly localized in the
inner nuclear layer of the retina, whereas the full-length FGFR1 form was
detected in the retinal Muller glial cells. FGF2 and FGFR1 mRNA levels greatly
increased in light-induced retinal degeneration. FGFR1 was detected in the radial
fibers of activated retinal Muller glial cells. In contrast, SR1 mRNA synthesis
followed a biphasic pattern of down- and up-regulation, and anti-SR1 staining was
intense in retinal pigmented epithelial cells. The synthesis of SR1 and FGFR1
specifically and independently regulated in normal and degenerating retina
suggests that changes in the proportion of various FGFR forms may control the
bioavailability of FGFs and thus their potential as neurotrophic factors. This
was demonstrated in vivo during retinal degeneration when recombinant SR1
inhibited the neurotrophic activity of exogenous FGF2 and increased damaging
effects of light by inhibiting endogenous FGF. This study highlights the
significance of the generation of SR1 in normal and pathological conditions.
PMID- 9763445
TI - A late mitotic regulatory network controlling cyclin destruction in Saccharomyces
cerevisiae.
AB - Exit from mitosis requires the inactivation of mitotic cyclin-dependent kinase
cyclin complexes, primarily by ubiquitin-dependent cyclin proteolysis. Cyclin
destruction is regulated by a ubiquitin ligase known as the anaphase-promoting
complex (APC). In the budding yeast Saccharomyces cerevisiae, members of a large
class of late mitotic mutants, including cdc15, cdc5, cdc14, dbf2, and tem1,
arrest in anaphase with a phenotype similar to that of cells expressing
nondegradable forms of mitotic cyclins. We addressed the possibility that the
products of these genes are components of a regulatory network that governs
cyclin proteolysis. We identified a complex array of genetic interactions among
these mutants and found that the growth defect in most of the mutants is
suppressed by overexpression of SPO12, YAK1, and SIC1 and is exacerbated by
overproduction of the mitotic cyclin Clb2. When arrested in late mitosis, the
mutants exhibit a defect in cyclin-specific APC activity that is accompanied by
high Clb2 levels and low levels of the anaphase inhibitor Pds1. Mutant cells
arrested in G1 contain normal APC activity. We conclude that Cdc15, Cdc5, Cdc14,
Dbf2, and Tem1 cooperate in the activation of the APC in late mitosis but are not
required for maintenance of that activity in G1.
PMID- 9763447
TI - cut11(+): A gene required for cell cycle-dependent spindle pole body anchoring in
the nuclear envelope and bipolar spindle formation in Schizosaccharomyces pombe.
AB - The "cut" mutants of Schizosaccharomyces pombe are defective in spindle formation
and/or chromosome segregation, but they proceed through the cell cycle, resulting
in lethality. Analysis of temperature-sensitive alleles of cut11(+) suggests that
this gene is required for the formation of a functional bipolar spindle.
Defective spindle structure was revealed with fluorescent probes for tubulin and
DNA. Three-dimensional reconstruction of mutant spindles by serial sectioning and
electron microscopy showed that the spindle pole bodies (SPBs) either failed to
complete normal duplication or were free floating in the nucleoplasm.
Localization of Cut11p tagged with the green fluorescent protein showed punctate
nuclear envelope staining throughout the cell cycle and SPBs staining from early
prophase to mid anaphase. This SPB localization correlates with the time in the
cell cycle when SPBs are inserted into the nuclear envelope. Immunoelectron
microscopy confirmed the localization of Cut11p to mitotic SPBs and nuclear pore
complexes. Cloning and sequencing showed that cut11(+) encodes a novel protein
with seven putative membrane-spanning domains and homology to the Saccharomyces
cerevisiae gene NDC1. These data suggest that Cut11p associates with nuclear pore
complexes and mitotic SPBs as an anchor in the nuclear envelope; this role is
essential for mitosis.
PMID- 9763446
TI - Identification of regulators for Ypt1 GTPase nucleotide cycling.
AB - Small GTPases of the Ypt/Rab family are involved in the regulation of vesicular
transport. Cycling between the GDP- and GTP-bound forms and the accessory
proteins that regulate this cycling are thought to be crucial for Ypt/Rab
function. Guanine nucleotide exchange factors (GEFs) stimulate both GDP loss and
GTP uptake, and GTPase-activating proteins (GAPs) stimulate GTP hydrolysis.
Little is known about GEFs and GAPs for Ypt/Rab proteins. In this article we
report the identification and initial characterization of two factors that
regulate nucleotide cycling by Ypt1p, which is essential for the first two steps
of the yeast secretory pathway. The Ypt1p-GEF stimulates GDP release and GTP
uptake at least 10-fold and is specific for Ypt1p. Partially purified Ypt1p-GEF
can rescue the inhibition caused by the dominant-negative Ypt1p-D124N mutant of
in vitro endoplasmic reticulum-to-Golgi transport. This mutant probably blocks
transport by inhibiting the GEF, suggesting that we have identified the
physiological GEF for Ypt1p. The Ypt1p-GAP stimulates GTP hydrolysis by Ypt1p up
to 54-fold, has a higher affinity for the GTP-bound form of Ypt1p than for the
GDP-bound form, and is specific to a subgroup of exocytic Ypt proteins. The Ypt1p
GAP activity is not affected by deletion of two genes that encode known Ypt GAPs,
GYP7 and GYP1, nor is it influenced by mutations in SEC18, SEC17, or SEC22, genes
whose products are involved in vesicle fusion. The GEF and GAP activities for
Ypt1p localize to particulate cellular fractions. However, contrary to the
predictions of current models, the GEF activity localizes to the fraction that
functions as the acceptor in an endoplasmic reticulum-to-Golgi transport assay,
whereas the GAP activity cofractionates with markers for the donor. On the basis
of our current and previous results, we propose a new model for the role of
Ypt/Rab nucleotide cycling and the factors that regulate this process.
PMID- 9763448
TI - The dynamic behavior of individual microtubules associated with chromosomes in
vitro.
AB - Mitotic movements of chromosomes are usually coupled to the elongation and
shortening of the microtubules to which they are bound. The lengths of
kinetochore-associated microtubules change by incorporation or loss of tubulin
subunits, principally at their chromosome-bound ends. We have reproduced aspects
of this phenomenon in vitro, using a real-time assay that displays directly the
movements of individual chromosome-associated microtubules as they elongate and
shorten. Chromosomes isolated from cultured Chinese hamster ovary cells were
adhered to coverslips and then allowed to bind labeled microtubules. In the
presence of tubulin and GTP, these microtubules could grow at their chromosome
bound ends, causing the labeled segments to move away from the chromosomes, even
in the absence of ATP. Sometimes a microtubule would switch to shortening,
causing the direction of movement to change abruptly. The link between a
microtubule and a chromosome was mechanically strong; 15 pN of tension was
generally insufficient to detach a microtubule, even though it could add subunits
at the kinetochore-microtubule junction. The behavior of the microtubules in
vitro was regulated by the chromosomes to which they were bound; the frequency of
transitions from polymerization to depolymerization was decreased, and the speed
of depolymerization-coupled movement toward chromosomes was only one-fifth the
rate of shortening for microtubules free in solution. Our results are consistent
with a model in which each microtubule interacts with an increasing number of
chromosome-associated binding sites as it approaches the kinetochore.
PMID- 9763449
TI - A yeast t-SNARE involved in endocytosis.
AB - The ORF YOL018c (TLG2) of Saccharomyces cerevisiae encodes a protein that belongs
to the syntaxin protein family. The proteins of this family, t-SNAREs, are
present on target organelles and are thought to participate in the specific
interaction between vesicles and acceptor membranes in intracellular membrane
trafficking. TLG2 is not an essential gene, and its deletion does not cause
defects in the secretory pathway. However, its deletion in cells lacking the
vacuolar ATPase subunit Vma2p leads to loss of viability, suggesting that Tlg2p
is involved in endocytosis. In tlg2Delta cells, internalization was normal for
two endocytic markers, the pheromone alpha-factor and the plasma membrane uracil
permease. In contrast, degradation of alpha-factor and uracil permease was
delayed in tlg2Delta cells. Internalization of positively charged Nanogold shows
that the endocytic pathway is perturbed in the mutant, which accumulates Nanogold
in primary endocytic vesicles and shows a greatly reduced complement of early
endosomes. These results strongly suggest that Tlg2p is a t-SNARE involved in
early endosome biogenesis.
PMID- 9763450
TI - Overexpression of a novel rho family GTPase, RacC, induces unusual actin-based
structures and positively affects phagocytosis in Dictyostelium discoideum.
AB - Rho family proteins have been implicated in regulating various cellular
processes, including actin cytoskeleton organization, endocytosis, cell cycle,
and gene expression. In this study, we analyzed the function of a novel
Dictyostelium discoideum Rho family protein (RacC). A cell line was generated
that conditionally overexpressed wild-type RacC three- to fourfold relative to
endogenous RacC. Light and scanning electron microscopy indicated that the
morphology of the RacC-overexpressing cells [RacC WT(+) cells] was significantly
altered compared with control cells. In contrast to the cortical F-actin
distribution normally observed, RacC WT(+) cells displayed unusual dorsal and
peripheral F-actin-rich surface blebs (petalopodia, for flower-like).
Furthermore, phagocytosis in the RacC WT(+) cells was induced threefold relative
to control Ax2 cells, whereas fluid-phase pinocytosis was reduced threefold,
primarily as the result of an inhibition of macropinocytosis. Efflux of fluid
phase markers was also reduced in the RacC WT(+) cells, suggesting that RacC may
regulate postinternalization steps along the endolysosomal pathway. Treatment of
cells with Wortmannin and LY294002 (phosphatidylinositol 3-kinase inhibitors)
prevented the RacC-induced morphological changes but did not affect phagocytosis,
suggesting that petalopodia are probably not required for RacC-induced
phagocytosis. In contrast, inactivating diacylglycerol-binding motif-containing
proteins by treating cells with the drug calphostin C completely inhibited
phagocytosis in control and RacC WT(+) cells. These results suggest that RacC
plays a role in actin cytoskeleton organization and phagocytosis in
Dictyostelium.
PMID- 9763451
TI - Activation and cellular localization of the cyclosporine A-sensitive
transcription factor NF-AT in skeletal muscle cells.
AB - The widely used immunosuppressant cyclosporine A (CSA) blocks nuclear
translocation of the transcription factor, NF-AT (nuclear factor of activated T
cells), preventing its activity. mRNA for several NF-AT isoforms has been shown
to exist in cells outside of the immune system, suggesting a possible mechanism
for side effects associated with CSA treatment. In this study, we demonstrate
that CSA inhibits biochemical and morphological differentiation of skeletal
muscle cells while having a minimal effect on proliferation. Furthermore, in vivo
treatment with CSA inhibits muscle regeneration after induced trauma in mice.
These results suggest a role for NF-AT-mediated transcription outside of the
immune system. In subsequent experiments, we examined the activation and cellular
localization of NF-AT in skeletal muscle cells in vitro. Known pharmacological
inducers of NF-AT in lymphoid cells also stimulate transcription from an NF-AT
responsive reporter gene in muscle cells. Three isoforms of NF-AT (NF-ATp, c, and
4/x/c3) are present in the cytoplasm of muscle cells at all stages of myogenesis
tested. However, each isoform undergoes calcium-induced nuclear translocation
from the cytoplasm at specific stages of muscle differentiation, suggesting
specificity among NF-AT isoforms in gene regulation. Strikingly, one isoform (NF
ATc) can preferentially translocate to a subset of nuclei within a single
multinucleated myotube. These results demonstrate that skeletal muscle cells
express functionally active NF-AT proteins and that the nuclear translocation of
individual NF-AT isoforms, which is essential for the ability to coordinate gene
expression, is influenced markedly by the differentiation state of the muscle
cell.
PMID- 9763452
TI - A mutation in a novel yeast proteasomal gene, RPN11/MPR1, produces a cell cycle
arrest, overreplication of nuclear and mitochondrial DNA, and an altered
mitochondrial morphology.
AB - We report here the functional characterization of an essential Saccharomyces
cerevisiae gene, MPR1, coding for a regulatory proteasomal subunit for which the
name Rpn11p has been proposed. For this study we made use of the mpr1-1 mutation
that causes the following pleiotropic defects. At 24 degreesC growth is delayed
on glucose and impaired on glycerol, whereas no growth is seen at 36 degreesC on
either carbon source. Microscopic observation of cells growing on glucose at 24
degreesC shows that most of them bear a large bud, whereas mitochondrial
morphology is profoundly altered. A shift to the nonpermissive temperature
produces aberrant elongated cell morphologies, whereas the nucleus fails to
divide. Flow cytometry profiles after the shift to the nonpermissive temperature
indicate overreplication of both nuclear and mitochondrial DNA. Consistently with
the identification of Mpr1p with a proteasomal subunit, the mutation is
complemented by the human POH1 proteasomal gene. Moreover, the mpr1-1 mutant
grown to stationary phase accumulates ubiquitinated proteins. Localization of the
Rpn11p/Mpr1p protein has been studied by green fluorescent protein fusion, and
the fusion protein has been found to be mainly associated to cytoplasmic
structures. For the first time, a proteasomal mutation has also revealed an
associated mitochondrial phenotype. We actually showed, by the use of [rho
degrees] cells derived from the mutant, that the increase in DNA content per cell
is due in part to an increase in the amount of mitochondrial DNA. Moreover,
microscopy of mpr1-1 cells grown on glucose showed that multiple punctate
mitochondrial structures were present in place of the tubular network found in
the wild-type strain. These data strongly suggest that mpr1-1 is a valuable tool
with which to study the possible roles of proteasomal function in mitochondrial
biogenesis.
PMID- 9763453
TI - Chemotactic peptide-induced changes of intermediate filament organization in
neutrophils during granule secretion: role of cyclic guanosine monophosphate.
AB - In neutrophils activated to secrete with formyl-methionyl-leucyl-phenylalanine,
intermediate filaments are phosphorylated transiently by cyclic guanosine
monophosphate (cGMP)-dependent protein kinase (G-kinase). cGMP regulation of
vimentin organization was investigated. During granule secretion, cGMP levels
were elevated and intermediate filaments were transiently assembled at the
pericortex to areas devoid of granules and microfilaments. Microtubule and
microfilament inhibitors affected intermediate filament organization, granule
secretion, and cGMP levels. Cytochalasin D and nocodazole caused intermediate
filaments to assemble at the nucleus, rather than at the pericortex. cGMP levels
were elevated in neutrophils by both inhibitors; however, with cytochalasin D,
cGMP was elevated earlier and granule secretion was excessive. Nocodazole did not
affect normal cGMP elevations, but specific granule secretion was delayed.
LY83583, a guanylyl cyclase antagonist, inhibited granule secretion and
intermediate filament organization, but not microtubule or microfilament
organization. Intermediate filament assembly at the pericortex and secretion were
partially restored by 8-bromo-cGMP in LY83583-treated neutrophils, suggesting
that cGMP regulates these functions. G-kinase directly induced intermediate
filament assembly in situ, and protein phosphatase 1 disassembled filaments.
However, in intact cells stimulated with formyl-methionyl-leucyl-phenylalanine,
intermediate filament assembly is focal and transient, suggesting that vimentin
phosphorylation is compartmentalized. We propose that, in addition to changes in
microfilament and microtubule organization, granule secretion is also accompanied
by changes in intermediate filament organization, and that cGMP regulates
vimentin filament organization via activation of G-kinase.
PMID- 9763454
TI - Selection of gbeta subunits with point mutations that fail to activate specific
signaling pathways in vivo: dissecting cellular responses mediated by a
heterotrimeric G protein in Dictyostelium discoideum.
AB - In Dictyostelium discoideum, a unique Gbeta subunit is required for a G protein
coupled receptor system that mediates a variety of cellular responses. Binding of
cAMP to cAR1, the receptor linked to the G protein G2, triggers a cascade of
responses, including activation of adenylyl cyclase, gene induction, actin
polymerization, and chemotaxis. Null mutations of the cAR1, Galpha2, and Gbeta
genes completely impair all these responses. To dissect specificity in Gbetagamma
signaling to downstream effectors in living cells, we screened a randomly
mutagenized library of Gbeta genes and isolated Gbeta alleles that lacked the
capacity to activate some effectors but retained the ability to regulate others.
These mutant Gbeta subunits were able to link cAR1 to G2, to support gene
expression, and to mediate cAMP-induced actin polymerization, and some were able
to mediate to chemotaxis toward cAMP. None was able to activate adenylyl cyclase,
and some did not support chemotaxis. Thus, we separated in vivo functions of
Gbetagamma by making point mutations on Gbeta. Using the structure of the
heterotrimeric G protein displayed in the computer program CHAIN, we examined the
positions and the molecular interactions of the amino acids substituted in each
of the mutant Gbetas and analyzed the possible effects of each replacement. We
identified several residues that are crucial for activation of the adenylyl
cyclase. These residues formed an area that overlaps but is not identical to
regions where bovine Gtbetagamma interacts with its regulators, Galpha and
phosducin.
PMID- 9763455
TI - The cytoplasmic zinc finger protein ZPR1 accumulates in the nucleolus of
proliferating cells.
AB - The zinc finger protein ZPR1 translocates from the cytoplasm to the nucleus after
treatment of cells with mitogens. The function of nuclear ZPR1 has not been
defined. Here we demonstrate that ZPR1 accumulates in the nucleolus of
proliferating cells. The role of ZPR1 was examined using a gene disruption
strategy. Cells lacking ZPR1 are not viable. Biochemical analysis demonstrated
that the loss of ZPR1 caused disruption of nucleolar function, including
preribosomal RNA expression. These data establish ZPR1 as an essential protein
that is required for normal nucleolar function in proliferating cells.
PMID- 9763456
TI - Nucleolar localization elements of Xenopus laevis U3 small nucleolar RNA.
AB - The Nucleolar Localization Elements (NoLEs) of Xenopus laevis U3 small nucleolar
RNA (snoRNA) have been defined. Fluorescein-labeled wild-type U3 snoRNA injected
into Xenopus oocyte nuclei localized specifically to nucleoli as shown by
fluorescence microscopy. Injection of mutated U3 snoRNA revealed that the 5'
region containing Boxes A and A', known to be important for rRNA processing, is
not essential for nucleolar localization. Nucleolar localization of U3 snoRNA was
independent of the presence and nature of the 5' cap and the terminal stem. In
contrast, Boxes C and D, common to the Box C/D snoRNA family, are critical
elements for U3 localization. Mutation of the hinge region, Box B, or Box C' led
to reduced U3 nucleolar localization. Results of competition experiments
suggested that Boxes C and D act in a cooperative manner. It is proposed that Box
B facilitates U3 snoRNA nucleolar localization by the primary NoLEs (Boxes C and
D), with the hinge region of U3 subsequently base pairing to the external
transcribed spacer of pre-rRNA, thus positioning U3 snoRNA for its roles in rRNA
processing.
PMID- 9763458
TI - Functional and molecular differences between voltage-gated K+ channels of fast
spiking interneurons and pyramidal neurons of rat hippocampus.
AB - We have examined gating and pharmacological characteristics of somatic K+
channels in fast-spiking interneurons and regularly spiking principal neurons of
hippocampal slices. In nucleated patches isolated from basket cells of the
dentate gyrus, a fast delayed rectifier K+ current component that was highly
sensitive to tetraethylammonium (TEA) and 4-aminopyridine (4-AP) (half-maximal
inhibitory concentrations <0.1 mM) predominated, contributing an average of 58%
to the total K+ current in these cells. By contrast, in pyramidal neurons of the
CA1 region a rapidly inactivating A-type K+ current component that was TEA
resistant prevailed, contributing 61% to the total K+ current. Both types of
neurons also showed small amounts of the K+ current component mainly found in the
other type of neuron and, in addition, a slow delayed rectifier K+ current
component with intermediate properties (slow inactivation, intermediate
sensitivity to TEA). Single-cell RT-PCR analysis of mRNA revealed that Kv3
(Kv3.1, Kv3.2) subunit transcripts were expressed in almost all (89%) of the
interneurons but only in 17% of the pyramidal neurons. In contrast, Kv4 (Kv4.2,
Kv4.3) subunit mRNAs were present in 87% of pyramidal neurons but only in 55% of
interneurons. Selective block of fast delayed rectifier K+ channels, presumably
assembled from Kv3 subunits, by 4-AP reduced substantially the action potential
frequency in interneurons. These results indicate that the differential
expression of Kv3 and Kv4 subunits shapes the action potential phenotypes of
principal neurons and interneurons in the cortex.
PMID- 9763457
TI - Coilin can form a complex with the U7 small nuclear ribonucleoprotein.
AB - Coiled bodies (CBs) in the amphibian oocyte nucleus are spherical structures up
to 10 microm or more in diameter, much larger than their somatic counterparts,
which rarely exceed 1 microm. Oocyte CBs may have smaller granules attached to
their surface or embedded within them, which are identical in structure and
composition to the many hundreds of B-snurposomes found free in the nucleoplasm.
The matrix of the CBs contains the diagnostic protein p80-coilin, which is
colocalized with the U7 small nuclear ribonucleoprotein (snRNP), whereas the
attached and embedded B-snurposomes contain splicing snRNPs. A few of the 50-100
CBs in the oocyte nucleus are attached to lampbrush chromosomes at the histone
gene loci. By coimmunoprecipitation we show that coilin and the U7 snRNP can form
a weak but specific complex in the nucleoplasm, which is dependent on the special
U7 Sm-binding site. Under the same conditions coilin does not associate with the
U1 and U2 snRNPs. Coilin is a nucleic acid-binding protein, as shown by its
interaction with single-stranded DNA and with poly r(U) and poly r(G). We suggest
that an important function of coilin is to form a transient complex with the U7
snRNP and accompany it to the CBs. In the case of CBs attached to chromosomes at
the histone gene loci, the U7 snRNP is thus brought close to the actual site of
histone pre-mRNA transcription.
PMID- 9763459
TI - Electrochemical analysis of protein nitrotyrosine and dityrosine in the Alzheimer
brain indicates region-specific accumulation.
AB - HPLC with electrochemical array detection (HPLC-ECD) was used to quantify 3,3'
dityrosine (diTyr) and 3-nitrotyrosine (3-NO2-Tyr) in four regions of the human
brain that are differentially affected in Alzheimer's disease (AD). DiTyr and 3
NO2-Tyr levels were elevated consistently in the hippocampus and neocortical
regions of the AD brain and in ventricular cerebrospinal fluid (VF), reaching
quantities five- to eightfold greater than mean concentrations in brain and VF of
cognitively normal subjects. Uric acid, a proposed peroxynitrite scavenger, was
decreased globally in the AD brain and VF. The results suggest that AD
pathogenesis may involve the activation of oxidant-producing inflammatory enzyme
systems, including nitric oxide synthase.
PMID- 9763460
TI - Postsynaptic mechanisms underlying responsiveness of amygdaloid neurons to
nociceptin/orphanin FQ.
AB - Effects of nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the opioid
like orphan receptor (ORL), were investigated in the rat lateral (AL) and central
(ACe) amygdala in vitro. Approximately 98% of presumed projection neurons in the
AL responded to N/OFQ with an increase in inwardly rectifying potassium
conductance, resulting in an impairment in cell excitability. Half-maximal
effects were obtained at 30.6 nM; the Hill coefficient was 0.63. In the ACe, 31%
of the cells displayed responses similar to that in the AL, 44% were
nonresponsive, and 25% responded with a small potassium current with a linear
current-voltage relationship. Responses to N/OFQ were reduced by 100 microM Ba2+,
were insensitive to 10 microM naloxone, and were blocked by a selective ORL
antagonist, [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2 (IC50 = 760 nM). Involvement of G
proteins was indicated by irreversible effects and blockade of action of N/OFQ
during intracellular presence of GTP-gamma-S (100 microM) and GDP-beta-S (2 mM),
respectively, and prevention of responses after incubation in pertussis toxin
(500 ng/ml). These mechanisms may contribute to the role of N/OFQ in the
reduction of fear responsiveness and stress that have recently been suggested on
the basis of histochemical and behavioral studies.
PMID- 9763461
TI - 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyride neurotoxicity is attenuated in mice
overexpressing Bcl-2.
AB - The proto-oncogene Bcl-2 rescues cells from a wide variety of insults. Recent
evidence suggests that Bcl-2 protects against free radicals and that it increases
mitochondrial calcium-buffering capacity. The neurotoxicity of 1-methyl-4-phenyl
1,2,3, 6-tetrahydropyride (MPTP) is thought to involve both mitochondrial
dysfunction and free radical generation. We therefore investigated MPTP
neurotoxicity in both Bcl-2 overexpressing mice and littermate controls. MPTP
induced depletion of dopamine and loss of [3H]mazindol binding were significantly
attenuated in Bcl-2 overexpressing mice. Protection was more profound with an
acute dosing regimen than with daily MPTP administration over 5 d. 1-Methyl-4
phenylpyridinium (MPP+) levels after MPTP administration were similar in Bcl-2
overexpressing mice and littermates. Bcl-2 blocked MPP+-induced activation of
caspases. MPTP-induced increases in free 3-nitrotyrosine levels were blocked in
Bcl-2 overexpressing mice. These results indicate that Bcl-2 overexpression
protects against MPTP neurotoxicity by mechanisms that may involve both
antioxidant activity and inhibition of apoptotic pathways.
PMID- 9763462
TI - Neurotransmitter activation of inwardly rectifying potassium current in
dissociated hippocampal CA3 neurons: interactions among multiple receptors.
AB - We characterized potassium current activated by G-protein-coupled receptors in
acutely dissociated hippocampal CA3 neurons. Agonists for serotonin, adenosine,
and somatostatin receptors reliably activated a potassium-selective conductance
that was inwardly rectifying and that was blocked by 1 mM external Ba2+. The
conductance had identical properties to that activated by GABAB receptors in the
same cells. In one-half of the CA3 neurons that were tested, the metabotropic
glutamate agonist 1S,3R-ACPD also activated inwardly rectifying Ba2+-sensitive
potassium current. Activation of the current by serotonin and adenosine agonists
occurred with a time constant of 200-700 msec after a lag of 50-100 msec; on
removal of agonist the current deactivated with a time constant of 1-2 sec after
a lag of 200-400 msec. These kinetics are similar to GABAB-activated current and
consistent with a direct action of G-protein on the channels. For somatostatin,
both activation and deactivation were approximately fourfold slower, probably
limited by agonist binding and unbinding. The half-maximally effective agonist
concentrations were approximately 75 nM for somatostatin, approximately 100 nM
for serotonin, and approximately 400 nM for 2-chloroadenosine. Dose-response
relationships had Hill coefficients of 1.2-1.9, suggesting cooperativity in the
receptor-to-channel coupling mechanism. At saturating concentrations of agonists,
the combined application of baclofen and either somatostatin, serotonin, or 2
chloroadenosine produced effects that were subadditive and often completely
occlusive. However, at subsaturating concentrations the effects of baclofen and 2
chloroadenosine were supra-additive. Thus, low levels of different transmitters
can act synergistically in activating inwardly rectifying potassium current.
PMID- 9763463
TI - Regulation of tyrosine hydroxylase gene expression during transdifferentiation of
striatal neurons: changes in transcription factors binding the AP-1 site.
AB - We have shown previously that the synergistic interaction of acidic fibroblast
growth factor (aFGF) and a coactivator (dopamine, protein kinase A, or protein
kinase C activator) will induce the novel expression of tyrosine hydroxylase (TH)
in neurons of the developing striatum. In this study we sought to determine
whether, concomitant with TH expression, there were unique changes in
transcription factors binding the AP-1 regulatory element on the TH gene. Indeed,
we found a significant recruitment of proteins into TH-AP-1 complexes as well as
a shift from low- to high-affinity binding. Supershift experiments further
revealed dramatic changes in the proteins comprising the AP-1 complexes,
including recruitment of the transcriptional activators c-Fos, a novel Fos
protein, Fos-B, and Jun-D. Concomitantly, there was a decrease in repressor-type
factors ATF-2 and CREM-1. aFGF appeared to play a central but insufficient role,
requiring the further participation of at least one of the coactivating
substances. Experiments examining the signal transduction pathway involved in
mediating these nuclear events demonstrated that the presence of only an FGF (1,
2, 4, 9) competent to induce TH caused the phosphorylation of mitogen-activated
protein kinase (MAPK). Moreover, the treatment of cells with MEK/ERK inhibitors
(apigenin or PD98059) eliminated TH expression and the associated AP-1 changes,
suggesting that MAPK was a critical mediator of these events. We conclude that,
during transdifferentiation, signals may be transmitted via MAPK to the TH-AP-1
site to increase activators and reduce repressors, helping to shift the balance
in favor of TH gene expression at this and possibly other important regulatory
sites on the gene.
PMID- 9763464
TI - Activity-dependent modulation of glutamate receptors by polyamines.
AB - The mechanisms by which polyamines block AMPA and kainate receptors are not well
understood, but it has been generally assumed that they act as open-channel
blockers. Consistent with this, voltage-jump relaxation analysis of GluR6
equilibrium responses to domoate could be well fit, assuming that spermine,
spermidine, and philanthotoxin are weakly permeable open-channel blockers.
Analysis of rate constants for binding and dissociation of polyamines indicated
that the voltage dependence of block arose primarily from changes in koff rather
than kon. Experiments with changes in Na concentration further indicate that the
voltage dependence of polyamine block was governed by ion flux via open channels.
However, responses to 1 msec applications of L-Glu revealed slow voltage
dependent rise-times, suggesting that polyamines additionally bind to closed
states. A kinetic model, which included closed-channel block, reproduced these
observations but required that polyamines accelerate channel closure either
through an allosteric mechanism or by emptying the pore of permeant ions.
Simulations with this model reveal that polyamine block confers novel activity
dependent regulation on calcium-permeable AMPA and kainate receptor responses.
PMID- 9763465
TI - Staurosporine-induced apoptosis of cultured rat hippocampal neurons involves
caspase-1-like proteases as upstream initiators and increased production of
superoxide as a main downstream effector.
AB - We induced apoptosis in cultured rat hippocampal neurons by exposure to the
protein kinase inhibitor staurosporine (30 nM, 24 hr). Treatment with the
antioxidant (+/-)-alpha-tocopherol (100 microM) or the superoxide dismutase
mimetic manganese tetrakis (4-benzoyl acid) porphyrin (1 microM) significantly
reduced staurosporine-induced cell death. Using hydroethidine-based digital
videomicroscopy, we observed a significant increase in intracellular superoxide
production that peaked 6-8 hr into the staurosporine exposure. This increase
occurred in the absence of gross mitochondrial depolarization monitored with the
voltage-sensitive probe tetramethylrhodamine ethyl ester. We then prepared
extracts from staurosporine-treated hippocampal neurons and monitored cleavage of
acetyl-Tyr-Val-Ala-Asp-aminomethyl-coumarin and acetyl-Asp-Glu-Val-Asp-AMC,
fluorogenic substrates for caspase-1-like and caspase-3-like proteases,
respectively. Staurosporine caused a significant increase in caspase-1-like
activity that preceded intracellular superoxide production and reached a maximum
after 30 min. Caspase-3-like activity paralleled intracellular superoxide
production, with peak activity seen after 8 hr. Treatment with the corresponding
caspase-3-like protease inhibitor acetyl-Asp-Glu-Val-Asp-aldehyde (10 microM)
prevented the increase in caspase-3-like activity and staurosporine-induced
nuclear fragmentation, but failed to prevent the rise in superoxide production
and subsequent cell death. In contrast, treatment with caspase-1-like protease
inhibitors reduced both superoxide production and cell death. Of note,
antioxidants prevented superoxide production, caspase-3-like protease activity,
and cell death even when added 4 hr after the onset of the staurosporine
exposure. These results suggest a scenario of an early, caspase-1-like activity
followed by a delayed intracellular superoxide production that mediates
staurosporine-induced cell death of cultured rat hippocampal neurons.
PMID- 9763466
TI - Two distinct nicotinic receptors, one pharmacologically similar to the vertebrate
alpha7-containing receptor, mediate Cl currents in aplysia neurons.
AB - Ionotropic, nicotinic receptors have previously been shown to mediate both
inhibitory (Cl-dependent) and excitatory (cationic) cholinergic responses in
Aplysia neurons. We have used fast perfusion methods of agonist and antagonist
application to reevaluate the effects on these receptors of a wide variety of
cholinergic compounds, including a number of recently isolated and/or synthesized
alpha toxins [alpha-conotoxin (alphaCTx)] from Conus snails. These toxins have
been shown in previous studies to discriminate between the many types of
nicotinic receptors now known to be expressed in vertebrate muscle,
neuroendocrine, and neuronal cells. One of these toxins (alphaCTx ImI from the
worm-eating snail Conus imperialis) revealed that two kinetically and
pharmacologically distinct elements underlie the ACh-induced Cl-dependent
response in Aplysia neurons: one element is a rapidly desensitizing current that
is blocked by the toxin; the other is a slowly desensitizing current that is
unaffected by the toxin. The two kinetically defined elements were also found to
be differentially sensitive to different agonists. Finally, the proportion of the
rapidly desensitizing element to the sustained element was found to be cell
specific. These observations led to the conclusion that two distinct nicotinic
receptors mediate Cl currents in Aplysia neurons. The receptor mediating the
rapidly desensitizing Cl-dependent response shows a strong pharmacological
resemblance to the vertebrate alpha-bungarotoxin-sensitive, alpha7-containing
receptor, which is permeable to calcium and mediates a rapidly desensitizing
excitatory response.
PMID- 9763468
TI - Synaptic potentials mediated via alpha-bungarotoxin-sensitive nicotinic
acetylcholine receptors in rat hippocampal interneurons.
AB - Exogenous application of acetylcholine elicits inward currents in hippocampal
interneurons that are mediated via alpha-bungarotoxin-sensitive nicotinic
acetylcholine receptors, but synaptic responses mediated via such receptors have
never been reported in mammalian brain. In the present study, EPSCs were evoked
in hippocampal interneurons in rat brain slices by electrical stimulation and
were recorded by using whole-cell voltage-clamp techniques. Nicotinic EPSCs were
isolated pharmacologically, using antagonists to block other known types of
ligand-gated ion channels, and then were tested with either alpha-bungarotoxin or
methyllycaconitine, which are selective antagonists for nicotinic acetylcholine
receptors that contain the alpha7 receptor subunit. Each antagonist proved highly
effective at reducing the remaining synaptic current. Evoked alpha7-mediated
nicotinic EPSCs also were desensitized by superfusion with 1 microM nicotine, had
extrapolated reversal potentials near 0 mV, and showed strong inward
rectification at positive potentials. In several interneurons, methyllycaconitine
sensitive spontaneous EPSCs also were observed that exhibited a biphasic decay
rate very similar to that of the alpha7-mediated evoked response. These studies
provide the first demonstration of a functional cholinergic synapse in the
mammalian brain, in which the primary postsynaptic receptors are alpha
bungarotoxin-sensitive nicotinic acetylcholine receptors.
PMID- 9763469
TI - Induction of NF-kappaB activity during haloperidol-induced oxidative toxicity in
clonal hippocampal cells: suppression of NF-kappaB and neuroprotection by
antioxidants.
AB - Haloperidol (HP), a dopamine receptor antagonist, is cytotoxic to mouse clonal
hippocampal HT22 cells in a concentration-dependent manner and causes cell death
by oxidative stress. The addition of HP to HT22 cells led to an increase in
intracellular peroxides and a time-dependent drop in the intracellular
glutathione levels. HP-induced oxidative cell death was prevented by the pineal
hormone melatonin, its precursor N-acetyl serotonin, and most effectively by
vitamin E (alpha-tocopherol). These antioxidants inhibited the intracellular
peroxide accumulation and stabilized the glutathione content of HT22 cells after
the challenge with HP. At the molecular level, HP specifically induced the DNA
binding activity and the transcriptional activity of the redox-sensitive
transcription factor NF-kappaB. This enhanced NF-kappaB activity could be blocked
by the neuroprotective antioxidants. The specific suppression of NF-kappaB by its
inhibitor IkappaBalpha partially protected the cells against HP, indicating that
the activation of NF-kappaB may be involved in HP-induced oxidative cell death in
vitro.
PMID- 9763467
TI - Delayed release of neurotransmitter from cerebellar granule cells.
AB - At fast chemical synapses the rapid release of neurotransmitter that occurs
within a few milliseconds of an action potential is followed by a more sustained
elevation of release probability, known as delayed release. Here we characterize
the role of calcium in delayed release and test the hypothesis that facilitation
and delayed release share a common mechanism. Synapses between cerebellar granule
cells and their postsynaptic targets, stellate cells and Purkinje cells, were
studied in rat brain slices. Presynaptic calcium transients were measured with
calcium-sensitive fluorophores, and delayed release was detected with whole-cell
recordings. Calcium influx, presynaptic calcium dynamics, and the number of
stimulus pulses were altered to assess their effect on delayed release and
facilitation. Following single stimuli, delayed release can be separated into two
components: one lasting for tens of milliseconds that is steeply calcium
dependent, the other lasting for hundreds of milliseconds that is driven by low
levels of calcium with a nearly linear calcium dependence. The amplitude, calcium
dependence, and magnitude of delayed release do not correspond to those of
facilitation, indicating that these processes are not simple reflections of a
shared mechanism. The steep calcium dependence of delayed release, combined with
the large calcium transients observed in these presynaptic terminals, suggests
that for physiological conditions delayed release provides a way for cells to
influence their postsynaptic targets long after their own action potential
activity has subsided.
PMID- 9763470
TI - Noradrenergic-specific transcription of the dopamine beta-hydroxylase gene
requires synergy of multiple cis-acting elements including at least two Phox2a
binding sites.
AB - Dopamine beta-hydroxylase (DBH) catalyzes the conversion of dopamine to
noradrenaline and is selectively expressed in noradrenergic and adrenergic
neurons and neuroendocrine cells. Recent data from this laboratory showed that a
paired-like homeodomain (HD) protein, Phox2a, interacts with the HD-binding site
residing within a composite promoter of the human DBH gene, designated domain IV,
in a cell-specific manner and directly controls noradrenergic-specific DBH
promoter activity. In this report, we demonstrate that three additional protein
binding sites (i.e., domains I, II, and III) between domain IV and the TATA box
are critical for intact DBH promoter activity in noradrenergic cells and that
they activate DBH transcription in a highly concerted manner. Transient
transfection assays of mutant DBH reporter constructs indicated that domain I was
active in every cell line tested, whereas domain III was preferentially active in
DBH-positive cells. Remarkably, mutation of domain II was associated with
inactivation of DBH promoter activity exclusively in DBH-positive cell lines,
defining it as another noradrenergic-specific promoter element. The cell-specific
profile of the promoter function of these sequence motifs was further supported
by in vitro DNA-binding studies and Southwestern analysis. Furthermore,
competition and antibody supershift assays show that transcription factors Sp1
and AP2 are the cognate nuclear factors interacting with domains I and III,
respectively. Parallel evidence indicates that domain II is another Phox2a
binding site, demonstrating at least two binding sites for this factor in the
upstream DBH promoter. Strikingly, four tandem copies of domain II increased the
promoter activity of a minimal DBH promoter by 100- to 200-fold in DBH-positive
cell lines without compromising cell specificity. Cotransfection of Phox2a
expression vector dramatically increased the activity of the multiple domain II
promoter only in DBH-negative cell lines, confirming that domain II is responsive
to Phox2a. Collectively, this study emphasizes a critical role of Phox2a as well
as its functional synergism with other transcription factors (e.g., CREB, AP2,
and Sp1) in transcriptional activation of the DBH gene.
PMID- 9763471
TI - The endogenous calcium buffer and the time course of transducer adaptation in
auditory hair cells.
AB - Mechanoelectrical transducer currents in turtle auditory hair cells adapt to
maintained stimuli via a Ca2+-dependent mechanism that is sensitive to the level
of internal calcium buffer. We have used the properties of transducer adaptation
to compare the effects of exogenous calcium buffers in the patch electrode
solution with those of the endogenous buffer assayed with perforated-patch
recording. The endogenous buffer of the hair bundle was equivalent to 0.1-0.4 mM
BAPTA and, in a majority of cells, supported adaptation in an external Ca2+
concentration of 70 microM similar to that in turtle endolymph. The endogenous
buffer had a higher effective concentration, and the adaptation time constant was
faster in cells at the high-frequency end than at the low-frequency end of the
cochlea. Experiments using buffers with different Ca2+-binding rates or
dissociation constants indicated that the speed of adaptation and the resting
open probability of the transducer channels could be differentially regulated and
imply that the endogenous buffer must be a fast, high-affinity buffer. In some
hair cells, the transducer current did not decay exponentially during a sustained
stimulus but displayed damped oscillations at a frequency (58-230 Hz) that
depended on external Ca2+ concentration. The gradient in adaptation time constant
and the tuned transducer current at physiological levels of calcium buffer and
external Ca2+ suggest that transducer adaptation may contribute to hair cell
frequency selectivity. The results are discussed in terms of feedback regulation
of transducer channels mediated by Ca2+ binding at two intracellular sites.
PMID- 9763472
TI - Axonal injury alters alternative splicing of the retinal NR1 receptor: the
preferential expression of the NR1b isoforms is crucial for retinal ganglion cell
survival.
AB - Cellular-specific splicing of the retinal NMDAR1 receptor (NR1) and expression of
NMDAR2 receptor (NR2) subunits in response to optic nerve injury was investigated
by in situ hybridization in adult rats. A controlled optic nerve crush led to a
clear alteration in the expression of alternatively spliced NR1 variants in the
retinal ganglion cell layer (GCL). The NR1-2b and NR1-4b isoforms were
preferentially expressed between 2 d and 1 week after injury, whereas expression
for all other isoforms remained either unchanged or decreased to barely
detectable levels within 4 weeks. Cellular silver grain density for NR2 subunits
also declined in the GCL after trauma. To directly test the hypothesis that NR1b
expression is crucial for cell survival after axonal trauma, we administered
intraocularly an antisense oligonucleotide against the NR1b isoform 2 and 3 d
after injury. This led to a drastic loss of retrogradely labeled retinal ganglion
cells (RGCs). Antisense targeting clearly reduced retinal NR1 protein levels, as
judged by Western blot analysis, but had no effect on the cell number in control
retinas. These findings point toward injury-specific changes in alternative
splicing of the NR1 receptor, which are crucial for the survival of RGCs after
partial axonal trauma. We therefore propose that this reflects an adaptive,
rather than a pathogenic, cellular response to neurotrauma.
PMID- 9763473
TI - Overexpression of SOD1 in transgenic rats protects vulnerable neurons against
ischemic damage after global cerebral ischemia and reperfusion.
AB - Transient global cerebral ischemia resulting from cardiac arrest is known to
cause selective death in vulnerable neurons, including hippocampal CA1 pyramidal
neurons. It is postulated that oxygen radicals, superoxide in particular, are
involved in cell death processes. To test this hypothesis, we first used in situ
imaging of superoxide radical distribution by hydroethidine oxidation in
vulnerable neurons. We then generated SOD1 transgenic (Tg) rats with a five-fold
increase in copper zinc superoxide dismutase activity. The Tg rats and their non
Tg wild-type littermates were subjected to 10 min of global ischemia followed by
1 and 3 d of reperfusion. Neuronal damage, as assessed by cresyl violet staining
and DNA fragmentation analysis, was significantly reduced in the hippocampal CA1
region, cortex, striatum, and thalamus in SOD1 Tg rats at 3 d, as compared with
the non-Tg littermates. There were no changes in the hippocampal CA3 subregion
and dentate gyrus, resistant areas in both SOD1 Tg and non-Tg rats. Quantitative
analysis of the damaged CA1 subregion showed marked neuroprotection against
transient global cerebral ischemia in SOD1 Tg rats. These results suggest that
superoxide radicals play a role in the delayed ischemic death of hippocampal CA1
neurons. Our data also indicate that SOD1 Tg rats are useful tools for studying
the role of oxygen radicals in the pathogenesis of neuronal death after transient
global cerebral ischemia.
PMID- 9763474
TI - Three-dimensional structure and composition of CA3-->CA1 axons in rat hippocampal
slices: implications for presynaptic connectivity and compartmentalization.
AB - Physiological studies of CA3-->CA1 synaptic transmission and plasticity have
revealed both pre- and postsynaptic effects. Understanding the extent to which
individual presynaptic axonal boutons could provide local compartments for
control of synaptic efficacy and microconnectivity requires knowledge of their
three-dimensional morphology and composition. In hippocampal slices, serial
electron microscopy was used to examine a nearly homogeneous population of CA3-
>CA1 axons in the middle of stratum radiatum of area CA1. The locations of
postsynaptic densities (PSDs), vesicles, and mitochondria were determined along
75 axon segments (9.1 +/- 2.0 micrometer in length). Synapses, defined by the
colocalization of PSDs and vesicles, occurred on average at 2.7 micrometer
intervals along the axons. Most varicosities (68%) had one PSD, 19% had 2-4 PSDs,
and 13% had none. Synaptic vesicles occurred in 90% of the varicosities. One-half
(53%) of the varicosities lacked mitochondria, raising questions about their
regulation of ATP and Ca2+, and 8% of varicosities contained only mitochondria.
Eleven axons were reconstructed fully. The varicosities were oblong and varied
greatly in both length (1.1 +/- 0.7 micrometer) and volume (0.13 +/- 0.14
micrometer 3), whereas the intervaricosity shafts were narrow, tubular, and
similar in diameter (0.17 +/- 0.04 micrometer) but variable in length (1.4 +/-
1.2 micrometer). The narrow axonal shafts resemble dendritic spine necks and thus
could promote biochemical compartmentalization of individual axonal varicosities.
The findings raise the intriguing possibility of localized differences in
metabolism and connectivity among different axons, varicosities, and synapses.
PMID- 9763475
TI - Protease inhibitor coinfusion with amyloid beta-protein results in enhanced
deposition and toxicity in rat brain.
AB - Amyloid beta-protein, Abeta, is normally produced in brain and is cleared by
unknown mechanisms. In Alzheimer's disease (AD), Abeta accumulates in plaque-like
deposits and is implicated genetically in neurodegeneration. Here we investigate
mechanisms for Abeta degradation and Abeta toxicity in vivo, focusing on the
effects of Abeta40, which is the peptide that accumulates in apolipoprotein E4
associated AD. Chronic intraventricular infusion of Abeta40 into rat brain
resulted in limited deposition and toxicity. Coinfusion of Abeta40 with the
cysteine protease inhibitor leupeptin resulted in increased extracellular and
intracellular Abeta immunoreactivity. Analysis of gliosis and TUNEL in neuron
layers of the frontal and entorhinal cortex suggested that leupeptin exacerbated
Abeta40 toxicity. This was supported further by the neuronal staining of
cathepsin B in endosomes or lysosomes, colocalizing with intracellular Abeta
immunoreactivity in pyknotic cells. Leupeptin plus Abeta40 caused limited but
significant neuronal phospho-tau immunostaining in the entorhinal cortex.
Intriguingly, Abeta40 plus leupeptin induced intracellular accumulation of the
more toxic Abeta, Abeta42, in a small group of septal neurons. Leupeptin infusion
previously has been reported to interfere with lysosomal proteolysis and to
result in the accumulation of lipofuscin, dystrophic neurites, tau- and ubiquitin
positive inclusions, and structures resembling paired helical filaments.
Coinfusion of Abeta40 with the serine protease inhibitor aprotinin also increased
diffuse extracellular deposition but reduced astrocytosis and TUNEL and was not
associated with intracellular Abeta staining. Collectively, these data suggest
that an age or Alzheimer's-related defect in lysosomal/endosomal function could
promote Abeta deposition and DNA fragmentation in neurons and glia similar to
that found in Alzheimer's disease.
PMID- 9763476
TI - An early phase of embryonic Dlx5 expression defines the rostral boundary of the
neural plate.
AB - Relatively little is known about the molecular events that specify the
rostrocaudal axis of the neural plate. Here we show that a member of the Distal
less (Dlx) homeobox gene family, Dlx5, is one of the earliest known markers for
the most rostral ectoderm, before the formation of an overt neural plate. During
late gastrulation Dlx5 expression becomes localized to the anterior neural ridge,
which defines the rostral boundary of the neural plate, and also extends
caudolaterally, marking the region of the presumptive neural crest. Subsequently,
Dlx5 is expressed in tissues (olfactory epithelium, ventral cephalic epithelium)
that are believed to derive from the anterior neural ridge, based on the avian
fate map. The early phase of Dlx5 expression in the anterior neural ridge and its
derivatives is distinct from a later phase of expression in the ventral
telencephalon and diencephalon and also appears to be unique for Dlx5 among
members of the Dlx family. Another distinctive feature of Dlx5 expression is the
occurrence of an alternative transcript (deltaDlx5), which encodes a truncated
protein lacking the homeodomain, and represents a significant fraction of total
Dlx5 transcripts at all embryonic stages that were examined. In contrast with
full-length DLX5, the deltaDLX5 truncated protein is deficient in DNA-binding
activity and does not interact with the homeoprotein partner MSX1. Taken
together, our findings suggest that Dlx5 activity may be regulated via the
expression of an alternative transcript and demonstrate that Dlx5 marks the
anterior boundary of the neural plate.
PMID- 9763477
TI - Multiple restricted origin of oligodendrocytes.
AB - The plp gene encodes the proteolipid protein and its alternatively spliced
product DM-20, major proteins of CNS myelin. In the mouse, plp/dm-20 transcripts
are expressed beginning at embryonic day 9.5 (E9.5) by restricted foci of
germinative neuroepithelial cells. To determine the identity of the neural
precursors expressing plp/dm- 20, a zeomycin resistance gene fused to the lacZ
reporter was expressed in transgenic mice under the control of the plp regulatory
sequences. In the three different lines generated, the pattern of beta
galactosidase expression was similar and superimposable on the expression pattern
of endogenous plp/dm-20. Both in vivo and in vitro, the transgene was expressed
by O4(+) pre-oligodendrocytes, and later by RIP+ differentiated oligodendrocytes,
but not by neuronal cells, astrocytes, or radial glial cells. After zeomycin
selection, a dramatic enrichment in O4(+) pre-oligodendrocytes was observed in
cultures derived from E12.5 transgenic embryos. This enrichment indicates the
oligodendroglial specification of neural precursors that continuously express
plp/dm-20. Early plp/dm-20-expressing precursors, however, appear to be a
separate population from previously described PDGFRalpha oligodendrocyte
precursors, as shown by the striking differences in their (1) patterns of
distribution and (2) responsiveness to PDGF. These data suggest that
oligodendrocytes have a plural origin and that early plp/dm-20 defines one of the
neural lineages generating oligodendrocytes.
PMID- 9763478
TI - A role for tectal midline glia in the unilateral containment of retinocollicular
axons.
AB - Retinal fibers approach close to the tectal midline but do not encroach on the
other side. Just before the entry of retinal axons into the superior colliculus
(SC), a group of radial glia differentiates at the tectal midline; the
spatiotemporal deployment of these cells points to their involvement in the
unilateral containment of retinotectal axons. To test for such a barrier function
of the tectal midline cells, we used two lesion paradigms for disrupting their
radial processes in the neonatal hamster: (1) a heat lesion was used to destroy
the superficial layers of the right SC, including the midline region, and (2) a
horizontally oriented hooked wire was inserted from the lateral edge of the left
SC toward the midline and was used to undercut the midline cells, leaving intact
the retinorecipient layers in the right SC. In both cases, the left SC was
denervated by removing its contralateral retinal input. Animals were killed 12 hr
to 2 weeks later, after intraocular injections of anterograde tracers to label
the axons from the remaining eye. Both lesions resulted in degeneration of the
distal processes of the tectal raphe glia and in an abnormal crossing of the
tectal midline by retinal axons, leading to an innervation of the opposite
("wrong") tectum. The crossover occurred only where glial cell attachments were
disrupted. These results document that during normal development, the integrity
of the midline septum is critical in compartmentalizing retinal axons and in
retaining the laterality of the retinotectal projection.
PMID- 9763479
TI - Spine loss and other persistent alterations of hippocampal pyramidal cell
dendrites in a model of early-onset epilepsy.
AB - To explore the anatomical substrates for network hyperexcitability in adult rats
that become chronically epileptic after recurrent seizures in infancy, the
dendritic and axonal arbors of biocytin-filled hippocampal pyramidal cells were
reconstructed. On postnatal day 10, tetanus toxin was unilaterally injected into
the hippocampus and produced brief but recurrent seizures for 1 week. Later,
hippocampal slices taken from these rats exhibited synchronized network bursts in
area CA3C. Both the apical and basilar dendritic arbors of CA3C pyramidal cells
were markedly abnormal in these epileptic rats. There was a considerable
reduction in the density of dendrite spines, although the extent of this loss
could vary among dendritic segments. Spine density on terminal segments of the
basilar and apical dendrites was reduced on average by 35 and 20%, respectively.
In addition, the diameters of these same dendritic segments were markedly
reduced. Dendritic spine loss has previously been suggested to indicate a partial
deafferentation of epileptic neurons, but this interpretation is difficult to
reconcile with the critical role recurrent excitatory synaptic transmission plays
in the generation of synchronized network burst. In this study, axonal arbors of
CA3C pyramidal cells exhibited normal branching patterns, branching complexity,
and varicosity density. This suggests that if deafferentation occurs, synapses
other than recurrent excitatory ones are lost. The morphological abnormalities
reported here would be expected to significantly alter electrical signaling
within dendrites that may contribute importantly to seizures and other behavioral
sequelae of early-onset epilepsy.
PMID- 9763480
TI - Autocrine hepatocyte growth factor provides a local mechanism for promoting
axonal growth.
AB - In this report, we describe a novel local mechanism necessary for optimal axonal
growth that involves hepatocyte growth factor (HGF). Sympathetic neurons of the
superior cervical ganglion coexpress bioactive HGF and its receptor, the Met
tyrosine kinase, both in vivo and in vitro. Exogenous HGF selectively promotes
the growth but not survival of cultured sympathetic neurons; the magnitude of
this growth effect is similar to that observed with exogenous NGF. Conversely,
HGF antibodies that inhibit endogenous HGF decrease sympathetic neuron growth but
have no effect on survival. This autocrine HGF is required locally by sympathetic
axons for optimal growth, as demonstrated using compartmented cultures. Thus,
autocrine HGF provides a local, intrinsic mechanism for promoting neuronal growth
without affecting survival, a role that may be essential during developmental
axogenesis or after neuronal injury.
PMID- 9763481
TI - Patterns of status epilepticus-induced neuronal injury during development and
long-term consequences.
AB - The lithium-pilocarpine model of status epilepticus (SE) was used to study the
type and distribution of seizure-induced neuronal injury in the rat and its
consequences during development. Cell death was evaluated in hematoxylin- and
eosin-stained sections and by electron microscopy. Damage to the CA1 neurons was
maximal in the 2- and 3-week-old pups and decreased as a function of age. On the
other hand, damage to the hilar and CA3 neurons was minimal in the 2-week-old rat
pups but reached an adult-like pattern in the 3-week-old animals, and damage to
amygdalar neurons increased progressively with age. The 3-week-old animals also
demonstrated vulnerability of the dentate granule cells. To evaluate neuronal
apoptosis, we used terminal deoxynucleotidyl transferase-mediated biotinylated
UTP nick end labeling (TUNEL) stain, confocal fluorescence microscopy of ethidium
bromide-stained sections, electron microscopy, and DNA electrophoresis. Neurons
displaying all of those features of apoptotic death in response to SE were seen
in the CA1 region of the 2-week-old pups and in the hilar border of the dentate
granule cells of the 3-week-old animals. Some (3/11) of the animals that
underwent SE at 2 weeks of age and most of the animals that underwent SE at 3 or
4 weeks of age (8/11 and 6/8, respectively) developed spontaneous seizures later
in life; the latter showed SE-induced synaptic reorganization as demonstrated by
Timm methodology. These results provide strong evidence for the vulnerability of
the immature brain to seizure-induced damage, which bears features of both
necrotic and apoptotic death and contributes to synaptic reorganization and the
development of chronic epilepsy.
PMID- 9763482
TI - Multiple limbic regions mediate the disruption of prepulse inhibition produced in
rats by the noncompetitive NMDA antagonist dizocilpine.
AB - Prepulse inhibition (PPI), a phenomenon in which a weak prestimulus decreases the
startle response to an intense stimulus, provides an operational measure of
sensorimotor gating (a process by which an organism filters sensory information)
and is diminished in schizophrenia and schizotypal patients. The psychotomimetic
phencyclidine and its potent congener dizocilpine are noncompetitive antagonists
of the NMDA receptor complex, and they disrupt PPI in rodents, mimicking the
clinically observed PPI deficit. The neuroanatomical substrates mediating the PPI
disruptive effects of noncompetitive NMDA antagonists are unknown. The present
study sought to identify brain regions subserving the disruption of PPI produced
by noncompetitive NMDA antagonists in rats. PPI was measured in startle chambers
immediately after bilateral infusion of dizocilpine (0, 0.25, 1.25, and 6.25
microgram/0.5 microliter/side) into one of six brain regions: amygdala, dorsal
hippocampus, medial prefrontal cortex, nucleus accumbens, ventral hippocampus,
and dorsomedial thalamus. Dizocilpine significantly decreased PPI after infusion
into the amygdala or dorsal hippocampus. A trend toward PPI disruption was
observed with administration into medial prefrontal cortex. In contrast, no
change in PPI was produced by dizocilpine infusion into nucleus accumbens,
ventral hippocampus, or dorsomedial thalamus. Startle reactivity was increased by
dizocilpine infusion into amygdala, dorsal hippocampus, nucleus accumbens, and
dorsomedial thalamus, but not medial prefrontal cortex. These findings indicate
that multiple limbic forebrain regions mediate the ability of noncompetitive NMDA
antagonists to disrupt PPI and that the PPI-disruptive and the startle-increasing
effects of dizocilpine are mediated by different central sites.
PMID- 9763483
TI - Directional tuning of single motor units.
AB - The directional activity of whole muscles has been shown to be broadly and often
multimodally tuned, raising the question of how this tuning is subserved at the
level of single motor units (SMUs). Previously defined rules of SMU activation
would predict that units of the same muscle (or at least of the same
neuromuscular compartment) are activated homogeneously with activity peaks in the
same "best" direction(s). In the present study, the best directions of SMUs in
human biceps (both heads) and deltoid (anterior, medial, and posterior portions)
were determined by measuring the firing rate and threshold force of units for
recruitment during isometric force ramps in many different directions. For all
muscles studied, neighboring motor units could have significantly different best
directions, suggesting that each muscle receives multiple directional commands.
Furthermore, 17% of the units sampled clearly had a second-best direction,
consistent with a convergence of different directional commands onto the same
motoneuron. The best directions of the units changed gradually with location in
the muscle. Best directions did not cluster into separate groups, thus, not
supporting the existence of clearly distinguished neuromuscular compartments.
Instead, the results reveal a more gradually distributed activation of the biceps
and deltoid motoneuron pools. A model is proposed in which the central control
mechanism optimizes the fulfillment of the continuously changing directional
force requirements of a movement by gradually recruiting and derecruiting those
units ideally suited for the production of the required force vector at any given
time.
PMID- 9763484
TI - Reduced striatal dopamine transporter density in abstinent methamphetamine and
methcathinone users: evidence from positron emission tomography studies with
[11C]WIN-35,428.
AB - Methamphetamine and methcathinone are psychostimulant drugs with high potential
for abuse. In animals, methamphetamine and related drugs are known to damage
brain dopamine (DA) neurons, and this damage has recently been shown to be
detectable in living nonhuman primates by means of positron emission tomography
(PET) with [11C]WIN-35,428, a DA transporter (DAT) ligand. The present studies
determined whether living humans with a history of methamphetamine or
methcathinone abuse showed evidence of lasting decrements in brain DAT density.
PET studies were performed in 10 control subjects, six abstinent methamphetamine
users, four abstinent methcathinone users, and three patients with Parkinson's
disease (PD). On average, subjects had abstained from amphetamine use for
approximately 3 years. Before PET studies, all subjects underwent urine and blood
toxicology screens to rule out recent drug use. Compared with controls, abstinent
methamphetamine and methcathinone users had significant decreases in DAT density
in the caudate nucleus (-23 and -24%, respectively) and putamen (-25 and -16%,
respectively). Larger decreases in DAT density were evident in patients with PD
(47 and 68% in caudate and putamen, respectively). Neither methamphetamine nor
methcathinone users showed clinical signs of parkinsonism. Persistent reductions
of DAT density in methamphetamine and methcathinone users are suggestive of loss
of DAT or loss of DA terminals and raise the possibility that as these
individuals age, they may be at increased risk for the development of
parkinsonism or neuropsychiatric conditions in which brain DA neurons have been
implicated.
PMID- 9763485
TI - Short-term memory for reaching to visual targets: psychophysical evidence for
body-centered reference frames.
AB - Pointing to a remembered visual target involves the transformation of visual
information into an appropriate motor output, with a passage through short-term
memory storage. In an attempt to identify the reference frames used to represent
the target position during the memory period, we measured errors in pointing to
remembered three-dimensional (3D) targets. Subjects pointed after a fixed delay
to remembered targets distributed within a 22 mm radius volume. Conditions varied
in terms of lighting (dim light or total darkness), delay duration (0.5, 5.0, and
8.0 sec), effector hand (left or right), and workspace location. Pointing errors
were quantified by 3D constant and variable errors and by a novel measure of
local distortion in the mapping from target to endpoint positions. The
orientation of variable errors differed significantly between light and dark
conditions. Increasing the memory delay in darkness evoked a reorientation of
variable errors, whereas in the light, the viewer-centered variability changed
only in magnitude. Local distortion measurements revealed an anisotropic
contraction of endpoint positions toward an "average" response along an axis that
points between the eyes and the effector arm. This local contraction was present
in both lighting conditions. The magnitude of the contraction remained constant
for the two memory delays in the light but increased significantly for the longer
delays in darkness. These data argue for the separate storage of distance and
direction information within short-term memory, in a reference frame tied to the
eyes and the effector arm.
PMID- 9763486
TI - Cervical dorsal rhizotomy enhances serotonergic innervation of phrenic
motoneurons and serotonin-dependent long-term facilitation of respiratory motor
output in rats.
AB - We tested the hypothesis that spinal plasticity elicited by chronic bilateral
cervical dorsal rhizotomy (C3-C5; CDR) has functional implications for
respiratory motor control. Surgery was performed on rats (CDR or sham-operated)
26 d before phrenic motoneurons were retrogradely labeled with cholera toxin.
Rats were killed 2 d later, and their spinal cords were harvested and processed
to reveal the cholera toxin-labeled phrenic motoneurons and serotonin
immunoreactive terminals. The number of serotonin-immunoreactive terminals within
5 micrometer of labeled phrenic motoneuron soma and primary dendrites increased
2.1-fold after CDR versus sham-operation. Time-dependent phrenic motor responses
to hypoxia were compared among CDR, sham-operated, and control rats.
Anesthetized, paralyzed, vagotomized, and artificially ventilated rats were
exposed to three, 5 min episodes of isocapnic hypoxia (FiO2 = 0.11), separated by
5 min hyperoxic intervals (FiO2 = 0.5). One hour after hypoxia, a long-lasting,
serotonin-dependent enhancement of phrenic motor output (long-term facilitation)
was observed in both sham and control rats. After CDR, long-term facilitation was
108 and 163% greater than control and sham responses, respectively. Pretreatment
of CDR rats with a 5-HT2 receptor antagonist (ketanserin tartrate, 2 mg/kg, i.v.)
before episodic hypoxia prevented long-term facilitation and revealed a modest (
28 +/- 13%; p < 0.05) long-lasting depression of phrenic motor output. The
results indicate that CDR: (1) increases serotonergic innervation of the phrenic
motor nucleus; and (2) augments serotonin-dependent long-term facilitation of
phrenic motor output. These results further suggest a form of plasticity based on
changes in the capacity for neuromodulation.
PMID- 9763487
TI - Amygdalar NMDA receptors are critical for new fear learning in previously fear
conditioned rats.
AB - NMDA receptors in the amygdala seem to be critical for fear conditioning in naive
rats. Recent spatial-learning studies suggest that previous learning protected
animals from the amnesic effect of NMDA antagonists on new learning (of a similar
behavioral task). Therefore, the present study examined whether blocking of NMDA
receptors in the basolateral nucleus of the amygdala (BLA) prevents new fear
learning in previously fear-conditioned rats, as measured by freezing behavior.
Intra-BLA infusions of the NMDA receptor antagonist DL-2-amino-5-phosphonovaleric
acid (APV) completely blocked fear conditioning to a tone stimulus in animals
that had previously been fear-conditioned to a light stimulus. Similar results
were obtained with intra-BLA infusions of APV before contextual fear conditioning
in rats that had been fear-conditioned to a different context. Additional
experiments showed that intra-BLA APV infusions substantially interfere with the
expression and extinction of conditioned fear to tone, light, and context
stimuli. Together, these results indicate that NMDA receptors in the BLA are
crucial for the encoding of new fear memories (i.e., the formation of specific
conditioned stimulus-unconditioned stimulus association), the expression of
conditioned fear responses, and the extinction of acquired fear.
PMID- 9763488
TI - Spatial firing properties of hippocampal CA1 populations in an environment
containing two visually identical regions.
AB - Populations of 10-39 CA1 pyramidal cells were recorded from four rats foraging
for food reward in an environment consisting of two nearly identical boxes
connected by a corridor. For each rat, a higher-than-chance fraction of cells had
similarly shaped spatial firing fields in both boxes, but other cells had
completely different fields in the two boxes. The level of correlation of fields
in the two boxes differed greatly across rats and, for three of the four rats,
across recording sessions. Thus, the factors controlling the level of correlation
are likely to be subtle. Two control manipulations were performed. First, the two
boxes were physically interchanged. In no case did firing fields move along with
the boxes. Second, on the final session of recording, the rat was started in the
south box, after having been started in the north box for every previous session.
For at least two of the four rats, the north fields from the previous session
were instantiated in the south during the first visit of the second session, but
thereafter reverted. Thus neither differences between the physical boxes nor
sensory input from outside the apparatus could account for the differences in
firing fields: most likely they were caused by a combination of learned
expectations and a neural mechanism for remembering movements. These findings
could be explained either by hypothesizing a more sophisticated attractor-map
architecture than has been proposed previously, or by hypothesizing that the
hippocampus conjunctively encodes both map information and some other type of
information.
PMID- 9763489
TI - Prepulse inhibition of the Tritonia escape swim.
AB - Presenting a weak stimulus just before a strong, startle stimulus reduces the
amplitude of the ensuing startle response in humans and other vertebrates. This
phenomenon, termed "prepulse inhibition" (PPI), appears to function to reduce
distraction while processing sensory input. To date, no detailed neural mechanism
has been described for PPI. Here we demonstrate PPI in the marine mollusk
Tritonia diomedea, which has a nervous system highly suitable for cellular
analyses. We found that a 100 msec vibrotactile prepulse prevented the animal's
escape swim response to a closely following 1 sec tail shock. This inhibition was
highly transient, with a significant effect lasting just 2.5 sec. These findings
indicate that the Tritonia escape swim response undergoes a form of PPI
phenomenologically similar to that observed in vertebrates. Further tests showed
that the vibrotactile stimulus had no inhibitory effect if applied after tail
shock, while the animal was preparing to swim, but it acted to terminate swims
once they were actively under way. As a first step toward a cellular analysis of
PPI, we recorded from neurons of the swim circuit in a semi-intact preparation
and found that the vibrotactile stimulus used in the behavioral experiments also
prevented the tail shock-elicited swim motor program. These results represent the
first explicit demonstration of PPI in an invertebrate and establish Tritonia as
a model system for analyzing its physiological basis.
PMID- 9763490
TI - Correlative ultrastructural distribution of neurotensin receptor proteins and
binding sites in the rat substantia nigra.
AB - Neurotensin (NT) produces various stimulatory effects on dopaminergic neurons of
the rat substantia nigra. To gain insight into the subcellular substrate for
these effects, we compared by electron microscopy the distribution of
immunoreactive high-affinity NT receptor proteins (NTRH) with that of high
affinity 125I-NT binding sites in this region of rat brain. Quantitative analysis
showed a predominant association of immunogold and radioautographic labels with
somata and dendrites of presumptive dopaminergic neurons, and a more modest
localization in myelinated and unmyelinated axons and astrocytic leaflets. The
distributions of immunoreactive NTRH and 125I-NT binding sites along
somatodendritic plasma membranes were highly correlated and homogeneous,
suggesting that membrane-targeted NTRH proteins were functional and predominantly
extrasynaptic. Abundant immunocytochemically and radioautographically labeled
receptors were also detected inside perikarya and dendrites. Within perikarya,
these were found in comparable proportions over membranes of smooth endoplasmic
reticulum and Golgi apparatus, suggesting that newly synthesized receptor
proteins already possess the molecular and conformational properties required for
effective ligand binding. By contrast, dendrites showed a proportionally higher
concentration of immunolabeled than radiolabeled intracellular receptors. A
fraction of these immunoreactive receptors were found in endosomes, suggesting
that they had undergone ligand-induced internalization and were under a molecular
conformation and/or in a physical location that precluded their recognition by
and/or access to exogenous ligand. Our results provide the first evidence that
electron microscopic immunocytochemistry of the NT receptor identifies sites for
both the binding and trafficking of NT in the substantia nigra.
PMID- 9763491
TI - Nicotine selectively enhances NMDA receptor-mediated synaptic transmission during
postnatal development in sensory neocortex.
AB - The neurotransmitters acetylcholine (ACh) and glutamate have been separately
implicated in synaptic plasticity during development of sensory neocortex. Here
we show that these neurotransmitters can, in fact, act synergistically via their
actions at nicotinic ACh receptors (nAChRs) and NMDA receptors, respectively. To
determine how activation of nAChRs modifies glutamatergic EPSPs, we made whole
cell recordings from visualized pyramidal neurons in slices of rat auditory
cortex. Pulsed (pressure) ejection of nicotine onto apical dendrites selectively
enhanced EPSPs mediated by NMDA receptors without affecting AMPA/kainate
(AMPA/KA) receptor-mediated EPSPs. The enhancement occurred during a transient,
postnatal period of heightened cholinergic function [neurons tested on postnatal
day 8-16 (P8-16)], and not in the mature cortex (>P19). Three related findings
indicated the mechanism of action: (1) The specific alpha7 nAChR antagonist
methyllycaconitine citrate (MLA) blocked the effect of nicotine; (2) pulsed
nicotine did not enhance postsynaptic depolarizations induced by
iontophoretically applied NMDA; and (3) bath exposure to nicotine for several
minutes produced apparent nAChR desensitization and precluded enhancement of
EPSPs by pulsed nicotine. Together, the data suggest that nicotine acts at
rapidly desensitizing, presynaptic alpha7 nAChRs to increase glutamate release
onto postsynaptic NMDA receptors. The synergistic actions mediated by alpha7
nAChRs and NMDA receptors may contribute to experience-dependent synaptic
plasticity in sensory neocortex during early postnatal life.
PMID- 9763492
TI - The visuo-motor pathway in the local circuit of the rat superior colliculus.
AB - Intrinsic circuit of the superior colliculus (SC), in particular the pathway from
the optic tract (OT) to neurons in the intermediate layer (SGI), was investigated
by whole-cell patch-clamp recording in slice preparations obtained from 17- to 24
d-old rats. Stimulation of the OT induced monosynaptic EPSPs in neurons in the
superficial gray layer (SGS) and the optic layer (SO), and disynaptic or
polysynaptic EPSPs in a majority of SGI neurons. Stimulation of the SGS induced
monosynaptic or oligosynaptic EPSPs in the SGI neurons. Both the monosynaptic
EPSPs induced in the SGS/SO neurons by stimulation of the OT and those induced in
the SGI neurons by stimulation of the SGS were mediated by AMPA- and NMDA-type
glutamate receptors. Thus, we have clarified the existence of the glutamatergic
excitatory pathway from the OT to the SGI neurons via SGS and SO neurons. The
EPSPs in the SGI neurons induced by stimulation of the OT or SGS were remarkably
enhanced by bicuculline, suggesting that the signal transmission in this pathway
is under strong suppression by the GABAergic system.
PMID- 9763493
TI - Mice lacking the beta3 subunit of the GABAA receptor have the epilepsy phenotype
and many of the behavioral characteristics of Angelman syndrome.
AB - Angelman syndrome (AS) is a severe neurodevelopmental disorder resulting from a
deletion/mutation in maternal chromosome 15q11-13. The genes in 15q11-13
contributing to the full array of the clinical phenotype are not fully
identified. This study examines whether a loss or reduction in the GABAA receptor
beta3 subunit (GABRB3) gene, contained within the AS deletion region, may
contribute to the overall severity of AS. Disrupting the gabrb3 gene in mice
produces electroencephalographic abnormalities, seizures, and behavior that
parallel those seen in AS. The seizures that are observed in these mice showed a
pharmacological response profile to antiepileptic medications similar to that
observed in AS. Additionally, these mice exhibited learning and memory deficits,
poor motor skills on a repetitive task, hyperactivity, and a disturbed rest
activity cycle, features all common to AS. The loss of the single gene, gabrb3,
in these mice is sufficient to cause phenotypic traits that have marked
similarities to the clinical features of AS, indicating that impaired expression
of the GABRB3 gene in humans probably contributes to the overall phenotype of
Angelman syndrome. At least one other gene, the E6-associated protein ubiquitin
protein ligase (UBE3A) gene, has been implicated in AS, so the relative
contribution of the GABRB3 gene alone or in combination with other genes remains
to be established.
PMID- 9763494
TI - Medial forebrain bundle lesions fail to structurally and functionally disconnect
the ventral tegmental area from many ipsilateral forebrain nuclei: implications
for the neural substrate of brain stimulation reward.
AB - Lesions in the medial forebrain bundle rostral to a stimulating electrode have
variable effects on the rewarding efficacy of self-stimulation. We attempted to
account for this variability by measuring the anatomical and functional effects
of electrolytic lesions at the level of the lateral hypothalamus (LH) and by
correlating these effects to postlesion changes in threshold pulse frequency
(pps) for self-stimulation in the ventral tegmental area (VTA). We implanted True
Blue in the VTA and compared cell labeling patterns in forebrain regions of
intact and lesioned animals. We also compared stimulation-induced regional
[14C]deoxyglucose (DG) accumulation patterns in the forebrains of intact and
lesioned animals. As expected, postlesion threshold shifts varied: threshold pps
remained the same or decreased in eight animals, increased by small but
significant amounts in three rats, and increased substantially in six subjects.
Unexpectedly, LH lesions did not anatomically or functionally disconnect all
forebrain nuclei from the VTA. Most septal and preoptic regions contained
equivalent levels of True Blue label in intact and lesioned animals. In both
intact and lesioned groups, VTA stimulation increased metabolic activity in the
fundus of the striatum (FS), the nucleus of the diagonal band, and the medial
preoptic area. On the other hand, True Blue labeling demonstrated anatomical
disconnection of the accumbens, FS, substantia innominata/magnocellular preoptic
nucleus (SI/MA), and bed nucleus of the stria terminalis. [14C]DG autoradiography
indicated functional disconnection of the lateral preoptic area and SI/MA.
Correlations between patterns of True Blue labeling or [14C]deoxyglucose
accumulation and postlesion shifts in threshold pulse frequency were weak and
generally negative. These direct measures of connectivity concord with the
behavioral measures in suggesting a diffuse net-like connection between forebrain
nuclei and the VTA.
PMID- 9763495
TI - Decreased odor avoidance after electric shock in Drosophila mutants biases
learning and memory tests.
AB - The Drosophila mutants amnesiac, dunce (dnc), and rutabaga were isolated after
associative conditioning tests, during which animals were trained to associate
the presence of an odor with that of electric shocks (ES). In the absence of
conditioning, the odor avoidance (OA) of these mutants was shown to be normal,
indicating that their poor associative conditioning performance was attributable
to specific learning or memory deficits. However, I show that the OA of the
mutants is greatly decreased after their exposure to ES. This effect can last for
hours. These results strongly suggest that part of the defect displayed by these
mutants in associative conditioning tests does not correspond to a learning or
memory deficit but might arise from abnormal sensitivity to stressful stimuli. I
looked at the OA after ES of two previously characterized dnc mutants. Df(1)N79f
specifically decreases Dnc expression in the mushroom bodies, leading to a normal
level of learning but decreased memory. Df(1)N79f mutants displayed a normal OA
after ES. Df(1)N64j15 affects the entire brain expression of Dnc, leading to
decreased learning and memory. Df(1)N64j15 animals showed a strong decrease of
their OA after ES. Thus, the lack of Dnc "general" expression is most likely
responsible for the OA defect, which would be responsible for the apparent
learning defect after conditioning. In contrast, the Dnc phosphodiesterase
accumulated in the mushroom bodies would be involved specifically in memory
formation.
PMID- 9763497
TI - Editorial
AB - We are pleased that the International Journal of Infectious Diseases (IJID) has
been indexed in MEDLINE and Index Medicus. It is a tribute to those of you who
have submitted excellent papers, case reports, and reviews and to those who have
contributed thoughtful editorials. We expect that heightened exposure both online
and in libraries will result in increased submissions and that this will soon
warrant publication at bimonthly and eventually monthly intervals. Increased
frequency of publication depends on members of the International Society for
Infectious Diseases (ISID) and other colleagues and their submission of more
manuscripts of the highest scientific merit. We also welcome more letters and
encourage critical and spirited commentaries. We urge you to tell your libraries
about the IJID and to suggest that they subscribe. Likewise, colleagues who could
not attend our biannual meeting should be asked to subscribe as well as to submit
the results of their observations and investigations. Much of the credit for the
success of IJID goes to its editors and reviewers. The peer review process works
because of the expertise, diligence, and timeliness of the reviewers and the
experience and judgment of the editors. The editors select reviewers, consider
their comments, and determine how to respond to potential contributors. The
overall objective is to present information about infectious diseases that has
international significance. Since these data frequently originate from regions
where English is not the primary language, our staff will provide assistance in
editing manuscripts to improve grammar and usage. Command of the English language
is not a criterion for acceptance or rejection of a manuscript. However, it does
make it easier for the reviewers if a native English speaker has read and revised
the manuscript. The recent meeting of the ISID in Boston was clearly a huge
success, and the presentations were outstanding. We trust that many of you who
participated in this meeting will submit articles to the IJID. Suggestions for
supplements from this meeting or from other meetings also are welcomed. Our
second issue comprised the proceedings at the Jenner Symposium of the 7th
International Congress for Infectious Diseases in Hong Kong, June 10-13, 1996. An
independent supplement on fungal infections came from a symposium at the meeting
of the International Immunocompromised Host Society, June 23-26, 1996, Assisi,
Italy.
PMID- 9763496
TI - Synaptic regulation of action potential timing in neostriatal cholinergic
interneurons.
AB - Action potentials in neostriatal cholinergic interneurons recorded in vivo are
triggered by summation of two or three discrete synaptic depolarizations (Wilson
et al., 1990). The ability and precision with which EPSPs and IPSPs regulate
action potential timing was therefore investigated in vitro. Cholinergic
interneurons were identified on the basis of morphological and
electrophysiological characteristics in neostriatal slices taken from 2- to 3
week-old postnatal rats recorded at 24-26 degreesC. During periods of induced
regular firing, intrastriatal stimuli were used to evoke pharmacologically
isolated monosynaptic AMPA receptor-mediated EPSPs or GABAA receptor-mediated
IPSPs. EPSPs evoked during the interspike interval (ISI) produced a phase
dependent decrease in the ISI, whereas IPSPs produced a phase-independent
prolongation of the ISI. Injection of brief depolarizing currents mimicked the
action of EPSPs and revealed an alteration in the input resistance during the
ISI. In contrast to IPSPs, the ability of brief hyperpolarizing current
injections to delay spike generation was phase-dependent. After blockade of
GABAergic and glutamatergic synaptic transmission, stimuli failed to produce a
detectable conductance change but could still prolong the subsequent ISI
primarily through a D1 dopamine receptor-mediated enhancement of the
afterhyperpolarization (AHP). Hence, EPSPs are ideally suited to provide a
precise regulation of spike timing in cholinergic cells, whereas IPSPs are more
likely to influence the overall level of excitability. The D1-mediated modulation
of the AHP may contribute to the prolonged ISI seen in tonically active neurons
in vivo in monkeys trained to respond to a sensory cue.
PMID- 9763498
TI - Host factors that affect sexual transmission of HIV.
PMID- 9763499
TI - CD3+CD8+ cell levels as predictors of transmission in human immunodeficiency
virus-infected couples: a report from the heterosexual HIV transmission study.
AB - OBJECTIVE: The goal of this study was to identify in human immunodeficiency virus
(HIV)-infected individuals immunologic markers that correlated with transmission
of HIV by heterosexual contact. METHODS: In a case-control comparison of couples,
immunologic and viral parameters were evaluated in 343 HIV-positive individuals
who were members of 67 HIV-seroconcordant couples (both partners HIV positive)
and 211 HIV serodiscordant couples (one positive, one negative). RESULTS: The
most striking immunologic finding was the increased numbers of CD3+CD8+ cells
found in the index member of discordant couples as compared to the index member
of the concordant couples. Differences in CD3+CD8+ levels persisted after
adjustment for stage of disease and CD3+CD4+ count. This increase in the number
of CD3+CD8+ cells was accompanied by a concomitant decrease in the amount of
viral replication measured by both HIV culture endpoint and quantitative RNA
polymerase chain reaction (PCR). CONCLUSION: Data presented here further support
the role of CD3+CD8+ cells in suppressing or controlling viral activity, although
a causal role based on case-control data must be advanced cautiously. This in
vivo biologic function may help prevent or lower the risk of HIV transmission.
PMID- 9763500
TI - Immunogenicity and reactogenicity of a combined hepatitis A-hepatitis B vaccine
in adolescents.
AB - OBJECTIVE: To evaluate the immunogenicity and reactogenicity of two lots of a
combined hepatitis A-hepatitis B vaccine (HAV, HBV) in healthy 15 to 18 year
olds. DESIGN: This was a double-blind, randomized clinical study. Vaccine was
administered into the deltoid at 0, 1, and 6 months. Immunogenicity was assessed
by anti-HAV and anti-HBs antibody levels at 2, 6, and 7 months after the first
vaccine dose. Reactogenicity was assessed through use of 3-day diary cards
following each vaccination, plus recording other unsolicited reactions. RESULTS:
A total of 160 adolescents were vaccinated; 155 who were seronegative for
hepatitis A and B at baseline and who completed the study were included in the
immunogenicity analysis. The vaccine was well tolerated; most side effects were
local, of low intensity and short duration. Good immunogenicity was determined by
antibody titers. High rates of seropositivity (99.4%) were achieved after two
doses against HAV, and after three doses for anti-HBs (seroprotection = 98.7%).
CONCLUSIONS: This combination vaccine will be useful for immunizing selected high
risk groups in developed countries. In countries where endemicity is low for both
diseases, targeting students prior to risk of acquisition would be a feasible
preventive strategy.
PMID- 9763502
TI - Screening for human immunodeficiency virus type 1 and 2 in a Turkish blood donor
population.
AB - OBJECTIVES: To determine the prevalence of human immunodeficiency virus-1 and -2
infection in voluntary blood donors at a university hospital in the third largest
city of Turkey and to evaluate the HIV testing strategy for notifying blood
donors. METHODS: Between July 1995 and August 1997, 36,373 voluntary blood donors
who met the criteria for donating blood were tested for the presence of HIV-1 and
-2 antibodies by using an automated enzyme-linked fluorescent immunoassay.
Repeatedly reactive samples were subjected to a different enzyme-linked
immunosorbent assay (ELISA) and a line immunoassay (LIA) for the detection of
antibodies. RESULTS: Of the 36,373 samples tested 72 were found to be repeatedly
reactive or borderline by the first screening enzyme immunoassay (EIA). None of
the 72 samples was reactive by the second EIA. These samples were further tested
by LIA: 64 were negative on the line immunoassay and 8 were indeterminate. Three
of eight donors who had indeterminate results by LIA were tested for HIV-1 DNA by
polymerase chain reaction (PCR) and were found to be negative. One additional
donor with an indeterminate LIA was found to be negative by EIA and LIA during
the 6-month follow-up period. CONCLUSION: Donor questioning, repeat EIA testing,
LIA testing, and HIV-1 DNA analysis did not confirm evidence for HIV infection
among this blood donor population. Blood donor notification of test results
according to the World Health Organization (WHO) strategy III was found to be an
appropriate approach.
PMID- 9763501
TI - Expansion of epidemic dengue viral infections to Pakistan.
AB - OBJECTIVES: Antibodies to dengue viruses have occasionally been reported in
individuals in Pakistan, but the frequency of occurrence of dengue infection in
Pakistan is unclear. The first confirmed dengue hemorrhagic fever outbreak in
Pakistan occurred in 1994. In October 1995, the authors investigated an outbreak
of a febrile illness among employees of a construction contractor at a power
generation plant in Baluchistan, Pakistan, to determine the cause of illness and
recommend appropriate preventive measures. METHODS: The work site and living
arrangements were inspected, a questionnaire was administered, and serum samples
were collected from all consenting contractor employees and their families if
they lived at the camp. Sera were analyzed for IgM against dengue virus, using an
enzyme-linked immunosorbent assay. RESULTS: Interviews were conducted with 76
persons (mean age, 42y); 95% were men. Forty-two persons (55%) reported having
experienced fever, headache, or myalgia in the preceding 6 weeks. Fifty-seven
subjects (75%) had IgM antibodies against at least one dengue serotype; 45
subjects (59%) had IgM antibodies against dengue serotype 2. CONCLUSION: This was
an outbreak of dengue fever due to multiple serotypes of dengue virus. This
confirms that epidemic dengue infection was present in southern Pakistan for 2
consecutive years.
PMID- 9763504
TI - Pseudomonas aeruginosa bacteremia: an analysis of 123 episodes, with particular
emphasis on the effect of antibiotic therapy.
AB - OBJECTIVES: To review current experience with Pseudomonas aeruginosa bacteremia
and compare outcome of patients treated with single-drug, versus combination
therapy. METHODS: The charts of all patients with P. aeruginosa bacteremia
between 1990 and 1992 were reviewed, and pertinent demographic, clinical, and
bacteriologic data were retrieved. In addition, similar data were collected from
a series of patients with P. aeruginosa bacteremia from the literature of the
past 20 years. RESULTS: One hundred and twenty-three episodes of P. aeruginosa
bacteremia in 121 patients were identified. Most patients were older than 70
years, had at least one underlying condition, and had acquired the infection in
the hospital. Attributable mortality was 34%. After exclusion for early mortality
and inappropriate therapy, 57 patients remained eligible for comparison of
outcome according to therapy protocol. Mortality from infection was equal between
the group of 42 patients who received monotherapy and the 15 patients who
received combination therapy (14% and 13%, respectively). The literature review
revealed eight articles describing 21 to 410 episodes of Pseudomonas bacteremia.
The clinical characteristics of these series did not differ significantly from
those of the present series. CONCLUSIONS: Incidence, epidemiology, clinical
characteristics, and outcome of pseudomonas sepsis did not change significantly
over the past 2 decades. Appropriate monotherapy was as effective as combination
drug therapy for individuals with pseudomonas bacteremia surviving the first 2
days of infection.
PMID- 9763503
TI - Varicella infection and pneumonia among adults.
AB - OBJECTIVES: To demonstrate the clinical importance of adult chickenpox in terms
of morbidity, mortality, and impact on hospital services, in Al Ain, United Arab
Emirates. METHODS: A review was conducted of 607 consecutive hospitalized cases
of adult chickenpox (1985-1996, Al Ain Hospital) for clinical findings and risk
of developing varicella pneumonia. RESULTS: Leading clinical features were fever
(98.9%), myalgia (26.9%), cough (24.6%), headache (15.4%), pharyngitis (14.7%),
and profuse rash (12.2%). There were 26 cases of varicella pneumonia, of whom
three died with respiratory failure (hospital case fatality 0.5%). Multivariate
analysis (odds ratios in parenthesis) showed that cough (12.1), profuse rash
(4.5), fever for more than 1 week (3.9), and age over 34 years (2.3) were the
most significant predictors of pneumonia. CONCLUSIONS: Early aggressive therapy
with intravenous acyclovir is recommended in patients at risk of pneumonia. In
the community setting, there is a large proportion of adult immigrants
(especially from South Asia) who are seronegative and at risk of complications
and hospitalization. It is recommended that the varicella vaccine be offered to
new immigrants after screening, to benefit themselves and the nonexposed
community, and to reduce the economic burden of chickenpox on the health services
and employers.
PMID- 9763505
TI - Molecular analysis of the a determinant of HBsAg in children of HBeAg-positive
mothers upon failure of postexposure prophylaxis.
AB - OBJECTIVE: To investigate the a determinant of hepatitis B virus (HBV) S gene for
the presence of mutations responsible for vaccine failure. METHODS: The a
determinant of HBV S gene was amplified in sera obtained from 11 HBV-positive
infants and children born to asymptomatic HBeAg-positive mothers by nested
polymerase chain reaction (PCR) and subsequently subjected to direct sequencing.
The sequences obtained were translated into the corresponding amino acids and
compared to amino acid sequences of HBV subtype adr. All infants under
investigation had received recombinant hepatitis B vaccine within 24 hours after
delivery and had completed the recommended vaccination course, consisting of
three to four doses administered at defined intervals. RESULTS: The usual
divergence regarding genotype and subtype was identified among the 11 samples
tested. Only two exhibited a point mutation within the a determinant, one of
which consisted of a substitution of glycine with alanine at position 145, and
the other of a substitution of glutamine with arginine at position 129.
CONCLUSION: Eleven neonates were positive for HBV infection, and two of them
showed point mutations that might have rendered the virus resistant to the
vaccine, possibly due to a change in the S protein's secondary structure. Yet,
this remains a matter of speculation, since the other seven cases positive for
hepatitis B viral DNA merely demonstrated the usual genotype and subtype. The
presence of escape mutants of HBV can be considered rather negligible with
respect to vaccination programs, especially as the vaccine has been shown to
reduce hepatitis B, as well as hepatocellular carcinoma efficiently.
PMID- 9763506
TI - Evaluation of the serologic response against two consensus V3 loop peptides from
human immunodeficiency virus-1 in Cuban patients.
AB - OBJECTIVES: A retrospective study was conducted to evaluate the antibody response
of Cuban patients infected with human immunodeficiency virus (HIV)-1 against two
consensus peptides from the third variable domain (V3) loop of glycoprotein
gp120. METHODS: The study included sera from 10 individuals at different stages
of disease. Two 15-meric synthetic peptides designed from a consensus sequence,
belonging to group B or C of HIV-1, were used to determine antibody titers and
avidity indexes in an indirect enzyme-linked immunoassay. RESULTS: A high
reactivity against both peptides was detected, with 80% of the sera reacting with
at least one of the peptides. The antibody titers and avidity indexes did not
correlate with disease progression. Additionally, for one of the patients from
whom the virus had been isolated, a higher avidity index was found against the
homologous peptide. CONCLUSIONS: This study showed high reactivity against two
consensus peptides from the V3 loop of gp120 among patients with HIV. Large scale
studies are needed to determine whether the titers or avidity of anti-V3
antibodies, at the early stages of infection, are predictive of disease
progression. Both peptides are candidates for inclusion in experimental vaccines.
PMID- 9763507
TI - Catheter-related infection: an update on diagnosis, treatment, and prevention.
AB - Catheter-related infection (CRI) accounts for a large percentage of nosocomial
infections, and related bacteremia is a common complication. Bacteremia arises in
approximately 1 of 15 episodes of CRI and causes considerable morbidity and
occasional mortality, as well as increased medical costs. The diagnosis of CRI
and catheter-related bacteremia (CRB) is still a challenge for practitioners
treating catheterized patients. Semiquantitative tip culture by the roll-plate
method is the cornerstone for diagnosis of CRI in routine practice. However,
there is a great deal of interest in the alternative methods for diagnosing CRI
without catheter withdrawal, since treatment of the patient can be successfully
completed with the infected device maintained in place. The conservative
management of CRI includes perfusion of antibiotics through the infected catheter
and the antibiotic-lock technique (ALT). Catheter-related infection prevention is
accomplished mainly by strict adherence to hygienic practices in insertion and
manipulation of the catheter. However, knowledge of the pathophysiology of CRI
has led to the development of new sophisticated catheters and hubs that
incorporate mechanical and antibacterial barriers.
PMID- 9763509
TI - ELAV protein HuA (HuR) can redistribute between nucleus and cytoplasm and is
upregulated during serum stimulation and T cell activation.
AB - ELAV proteins are implicated in regulating the stability and translation of
cytokine and growth regulatory mRNAs such as GM-CSF, IL-2, c-myc, c-fos and GLUT1
by binding to their AU-rich 3'UTRs. The tissue-specific ELAV protein HuB (aka.
Hel-N1) is predominantly cytoplasmic and has been shown to stabilize GLUT1 and c
myc mRNAs and to increase their translation following ectopic expression in 3T3
L1 cells. We report that the most widely expressed mouse ELAV protein, mHuA, is
predominately nuclear in cultured NIH-3T3 cells, but is localized in the
cytoplasm during early G1 of the cell cycle. Therefore, much like the primarily
cytoplasmic HuB, HuA becomes temporally localized in the cytoplasm where it can
potentially regulate the stability or translation of bound mRNAs. Moreover, we
report that stimulation of mouse spleen cells using either mitogenic or sub
mitogenic levels of anti-CD3/CD28 resulted in a dramatic increase in the level of
HuA. Upregulation of HuA corresponds to previously documented increases in
cytokine expression which are due to increased mRNA stability following T cell
activation. Consistent with these findings, HuA was down regulated in quiescent
cells and upregulated in 3T3 cells following serum stimulation. The increase of
murine HuA during the cell cycle closely resembles that of cyclin B1 which peaks
in G2/M. Together with our earlier studies, these data indicate that mammalian
ELAV proteins function during cell growth and differentiation due in part to
their effects on posttranscriptional stability and translation of multiple growth
regulatory mRNAs. This supports the hypothesis that ELAV proteins can function as
transacting factors which affect a default pathway of mRNA degradation involved
in the expression of growth regulatory proteins.
PMID- 9763508
TI - A factor required for nonsense-mediated mRNA decay in yeast is exported from the
nucleus to the cytoplasm by a nuclear export signal sequence.
AB - In Saccharomyces cerevisiae, Upf3p is required for nonsense-mediated mRNA decay
(NMD). Although localized primarily in the cytoplasm, Upf3p contains three
sequence elements that resemble nuclear localization signals (NLSs) and two
sequence elements that resemble nuclear export signals (NESs). We found that a
cytoplasmic reporter protein localized to the nucleus when fused to any one of
the three NLS-like sequences of Upf3p. A nuclear reporter protein localized to
the cytoplasm when fused to one of the NES-like sequences (NES-A). We present
evidence that NES-A functions to signal the export of Upf3p from the nucleus.
Combined alanine substitutions in the NES-A element caused a re-distribution of
Upf3p to a subnuclear location identified as the nucleolus and conferred an Nmd-
phenotype. Single mutations in NES-A failed to affect the distribution of Upf3p
and were Nmd+. When an NES element from HIV-1 Rev was inserted near the C
terminus of a mutant Upf3p containing multiple mutations in NES-A, the
cytoplasmic distribution typical of wild-type Upf3p was restored but the cells
remained phenotypically Nmd-. These results suggest that NES-A is a functional
nuclear export signal. Combined mutations in NES-A may cause multiple defects in
protein function leading to an Nmd- phenotype even when export is restored.
PMID- 9763510
TI - Protein synthesizing units in presynaptic and postsynaptic domains of squid
neurons.
AB - Putative protein synthesizing domains, called plaques, are characterized in the
squid giant synapse and axon and in terminals of squid photoreceptor neurons.
Plaques are oval-shaped formations of about 1 microm in size, which (1) generate
signals that have spectroscopic electron energy loss characteristics of
ribosomes, (2) exhibit ribonuclease-sensitive binding of YOYO-1, a fluorescent
RNA/DNA dye, and (3) in part hybridize with a poly(dT) oligonucleotide. In the
giant synapse plaques are abundant in the postsynaptic area, but are absent in
the presynaptic terminal. In the cortical layer of the optic lobes, plaques are
localized in the large carrot-shaped presynaptic terminals of photoreceptor
neurons, where they are surrounded by synaptic vesicles and mitochondria.
Biochemical and autoradiographic data have documented that the protein synthetic
activity of squid optic lobe synaptosomes is largely due to the presynaptic
terminals of the photoreceptor neurons. The identification of ribosomes and
poly(A+)-mRNA in the plaques indicates that these structures are sites of local
protein synthesis in synaptic domains.
PMID- 9763511
TI - Tau interacts with src-family non-receptor tyrosine kinases.
AB - Tau and other microtubule-associated proteins promote the assembly and
stabilization of neuronal microtubules. While each microtubule-associated protein
has distinct properties, their in vivo roles remain largely unknown. Tau is
important in neurite outgrowth and axonal development. Recently, we showed that
the amino-terminal region of tau, which is not involved in microtubule
interactions, is important in NGF induced neurite outgrowth in PC12 cells. Here
we report that a proline rich sequence in the amino terminus of tau interacts
with the SH3 domains of fyn and src non-receptor tyrosine kinases. Tau and fyn
were co-immunoprecipitated from human neuroblastoma cells and co-localization of
tau and fyn was visualized in co-transfected NIH3T3 cells. Co-transfection of tau
and fyn also resulted in an alteration in NIH3T3 cell morphology, consistent with
an in vivo interaction. Fyn-dependent tyrosine phosphorylation of tau occurred in
transfected cells and tyrosine phosphorylated tau was identified in human
neuroblastoma cells as well. Our data suggest that tau is involved in signal
transduction pathways. An interaction between tau and fyn may serve as a
mechanism by which extracellular signals influence the spatial distribution of
microtubules. The tyrosine phosphorylation of tau by fyn may also have a role in
neuropathogenesis, as fyn is upregulated in Alzheimer's disease.
PMID- 9763512
TI - The C8/144B monoclonal antibody recognizes cytokeratin 15 and defines the
location of human hair follicle stem cells.
AB - Stem cells are vital for the homeostasis of self-renewing tissues such as the
hair follicle. Epithelial stem cells have been implicated in tumorigenesis and
wound healing, and their manipulation may have wide ranging applications
including gene therapy and tissue transplantation. Rodent hair follicle stem
cells have been localized to an area of the follicle called the bulge, however,
the identification and characterization of human hair follicle stem cells has
been hampered by a lack of cellular markers for this area. We have determined
that the C8/144B monoclonal antibody, originally generated against a short
intracytoplasmic peptide of CD8, preferentially immunostains hair follicle bulge
keratinocytes without staining the remaining hair follicle. Using expression
cloning, we identified cytokeratin 15 as the keratinocyte protein recognized by
the C8/144B monoclonal antibody. By delineating the bulge using this antibody, we
demonstrated that bulge cells possess a stem cell phenotype characterized by
their slowly-cycling nature, preferential proliferation at the onset of new hair
follicle growth, high level of beta1 integrin expression, and expression of
cytokeratin 19.
PMID- 9763513
TI - Tension-sensitive kinetochore phosphorylation in vitro.
AB - Many cells have a checkpoint that detects a single misattached chromosome and
delays anaphase, allowing time for error correction. Detection probably depends
on tension-sensitive kinetochore protein phosphorylation. Somehow, mechanical
tension, or some consequence of tension, produces a chemical change,
dephosphorylation. The mechanism of tension-mediated dephosphorylation can be
approached using an in vitro system. Earlier work showed that the kinetochores of
washed chromosomes from a mammalian cell line can be phosphorylated in vitro
simply by incubation with ATP and a phosphatase inhibitor. We confirm this for
chromosomes from insect meiotic cells. Thus, kinetochores of washed chromosomes
from diverse sources contain a complete phosphorylation system: a kinase, a
phosphatase and the substrate protein(s). We show that phosphorylation in vitro
is sensitive to tension, as it is in living cells. This makes the conditions
required for phosphorylation in vitro relevant to the process in living cells.
The phosphatase is ruled out as the tension-sensitive component in vitro, leaving
either the kinase or the substrate as the sensitive component. We show that a
kinase extracted from mammalian cells in mitosis phosphorylates the kinetochores
of insect meiotic chromosomes very effectively. The mammalian kinase under
phosphorylates the kinetochore of the insect's X-chromosome, just as the native
insect kinase does. This provides a clue to the evolution of a chromosome that is
not detected by the checkpoint. The mammalian kinase is not tightly bound to the
chromosome and thus functions primarily in solution. This suggests that the
substrate's phosphorylatable groups are freely available to outside constituents,
e.g. regulators, as well as to the kinetochore's own kinase and phosphatase.
PMID- 9763514
TI - Cytoplasmic calcium gradients and calmodulin in the early development of the
fucoid alga Pelvetia compressa.
AB - The predicted existence of cytoplasmic Ca2+ gradients during the
photopolarization of the zygotes of the brown algae, Pelvetia and Fucus, has
proved to be difficult to establish, and the downstream targets of the putative
gradients are not known. We have used quantitative microinjection of the long
excitation wavelength Ca2+ indicator, Calcium Crimson, and of antibodies against
calmodulin to investigate these matters in the zygotes and early embryos of
Pelvetia. We found that there is a window of cytoplasmic Calcium Crimson
concentration that gives an adequate signal above autofluorescence yet allows
normal development of the zygotes. As Calcium Crimson is not a ratiometric
indicator, we injected other zygotes with a Ca2+-insensitive dye, rhodamine B,
and imaged the cells at the same time that Calcium Crimson-injected cells were
imaged. Ratios were calculated by dividing the averaged pixel values of Calcium
Crimson images by the averaged pixel values of corresponding rhodamine B images.
By this method, we observed the formation of a cytoplasmic Ca2+ gradient within
one hour of the exposure of the cells to unilateral blue light during the
photosensitive period. The region of high Ca2+ was localized to and predictive of
the site of future rhizoid formation. We validated this somewhat indirect method
by applying it to the growing rhizoid, where the existence of a tip-localized
Ca2+ gradient is well established. The method clearly revealed the known
gradient. The injection of ungerminated zygotes with antibodies made against
Dictyostelium calmodulin inhibited germination, and this inhibition was abolished
if the calmodulin antibodies were coinjected with an excess of purified maize
calmodulin. Likewise, the growth of the rhizoids was inhibited by calmodulin
antibody injections. The fungus-derived calmodulin antagonist, ophiobolin A,
which has previously been shown to be a potent inhibitor of germination, also
inhibited rhizoidal growth. Our results provide evidence that a cytoplasmic Ca2+
gradient is present during photopolarization and that calmodulin acts as a
mediator of Ca2+ gradients throughout the early developmental processes of
germination and rhizoidal growth in Pelvetia compressa.
PMID- 9763515
TI - H2O2 acts on cellular membranes to generate ceramide signaling and initiate
apoptosis in tracheobronchial epithelial cells.
AB - Hydrogen peroxide (H2O2) is an inflammatory oxidant which contributes to the
pathogenesis of chronic diseases such as lung injury of the respiratory tract,
atherosclerosis and cancer. The mechanisms and target sites of this reactive
oxidant are mainly unknown. So far there are opposing reports as to whether
reactive oxidants inhibit or promote apoptosis. We activated the death pathway in
primary tracheobronchial epithelial (TBE) cells with H2O2 (20-200 microM) and
observed the morphological changes, DNA laddering patterns, and DNA fragmentation
associated with apoptosis. Elevation of ceramide with exogenous ceramide analogs
was sufficient for apoptosis induction with the same characteristics and in the
same time frame. H2O2 induced rapid sphingomyelin hydrolysis to ceramide, the
elevation of which paralleled the induction of apoptosis. Furthermore, H2O2 acted
directly on TBE cells membrane preparations devoid of nuclei, stimulating
sphingomyelin hydrolysis through a neutral Mg2+ dependent sphingomyelinase
(SMase). These data suggest that the formation of ceramide from sphingomyelin in
the plasma membrane is a key event in H2O2-induced apoptosis in tracheobronchial
epithelial cells.
PMID- 9763516
TI - Transport of ER vesicles on actin filaments in neurons by myosin V.
AB - Axoplasmic organelles in the giant axon of the squid have been shown to move on
both actin filaments and microtubules and to switch between actin filaments and
microtubules during fast axonal transport. The objectives of this investigation
were to identify the specific classes of axoplasmic organelles that move on actin
filaments and the myosin motors involved. We developed a procedure to isolate
endoplasmic reticulum (ER) from extruded axoplasm and to reconstitute its
movement in vitro. The isolated ER vesicles moved on exogenous actin filaments
adsorbed to coverslips in an ATP-dependent manner without the addition of soluble
factors. Therefore myosin was tightly bound and not extracted during isolation.
These vesicles were identified as smooth ER by use of an antibody to an ER
resident protein, ERcalcistorin/protein disulfide isomerase (EcaSt/PDI).
Furthermore, an antibody to squid myosin V was used in immunogold EM studies to
show that myosin V localized to these vesicles. The antibody was generated to a
squid brain myosin (p196) that was classified as myosin V based on comparisons of
amino acid sequences of tryptic peptides of this myosin with those of other known
members of the myosin V family. Dual labeling with the squid myosin V antibody
and a kinesin heavy chain antibody showed that the two motors colocalized on the
same vesicles. Finally, antibody inhibition experiments were performed with two
myosin V-specific antibodies to show that myosin V motor activity is required for
transport of vesicles on actin filaments in axoplasm. One antibody was made to a
peptide in the globular tail domain and the other to the globular head fragment
of myosin V. Both antibodies inhibited vesicle transport on actin filaments by
greater than 90% compared to controls. These studies provide the first direct
evidence that ER vesicles are transported on actin filaments by myosin V. These
data confirm the role of actin filaments in fast axonal transport and provide
support for the dual filament model of vesicle transport.
PMID- 9763517
TI - N-terminal domain of Gpa1 (G protein alpha) subunit) is sufficient for plasma
membrane targeting in yeast Saccharomyces cerevisiae.
AB - G proteins play a central role in transmitting signals from cell surface
receptors to effector proteins inside the cell. Signaling can only occur,
however, if all these protein components are properly assembled and localized at
the plasma membrane. Past studies have shown that certain segments within the N
terminal region of the G protein alpha subunit are necessary for membrane
attachment. Here we identify a region within the yeast G alpha (Gpa1) that is
sufficient for membrane attachment, as well as for specific targeting to the
plasma membrane. Initially, we constructed chimeric proteins that replace the N
terminus of mammalian Gsalpha with the corresponding sequence from Gpa1. Gsalpha
is inefficiently targeted to the yeast plasma membrane and therefore cannot fully
complement the loss of Gpa1. Gpa1-Gsaplha chimeras were assayed for proper
membrane localization by functional complementation of a gpa1Delta ;) mutant, and
by sucrose density gradient fractionation of cell membranes. Most of the chimeras
tested, including one with only the N-terminal 7 amino acids from Gpa1, exhibited
normal membrane targeting and complementing activity. We also fused various
lengths of N-terminal Gpa1 sequence to glutathione-S-transferase (GST), a
heterologous protein normally expressed in the cytoplasm. The first 67- 36- or 9
amino acids of Gpa1 were all sufficient to direct GST specifically to the plasma
membrane in yeast. This analysis defines the extreme N terminus of Gpa1 as the
primary determinant of proper membrane targeting, and represents an essential
step towards isolating and identifying G protein-targeting proteins within the
plasma membrane.
PMID- 9763519
TI - Jeffrey M. hoeg
PMID- 9763518
TI - Axonal outgrowth of cultured neurons is not limited by growth cone competition.
AB - We have examined the question of scarcity-driven competition for outgrowth among
growth cones of a single neuron. We measured spontaneous neurite elongation rates
from 85 hours of videotape of the arbors of 31 chick sensory neurons in culture.
These rate measurements were analyzed in ten minute periods that allowed cell
bodies to be classified as to the number of their growth cones and the elongation
to be analyzed as a series of discrete events. Comparing periods in which neurons
maintained simple bipolar morphology we find no temporal competition between the
two growth cones. That is, periods of above-average growth by one growth cone are
not compensated by below-average growth during the same period by its sibling
growth cone. Analyzing all outgrowth from a neuron based on its number of growth
cones shows that net elongation rate from a single cell body is a linear function
of the number of growth cones from 1 to 11. These observations suggest that
growth cones behave independently and are not limited by availability of
structural precursors. A surplus pool of structural precursors available for
normal growth is also indicated by the high capacity for growth from single
neurites when experimentally stimulated by mechanical tension. In addition,
towing one or more neurites at above average rates does not cause any decline in
simultaneous growth cone-mediated outgrowth from a single neuron compared to the
2-3 hour period prior to experimentally induced elongation. This high capacity
for growth combined with the often observed, intermittant growth behavior of
individual growth cones suggests that neurite outgrowth is intrinsically limited
primarily by poor growth cone 'performance,' not scarcity-driven competition. We
postulate that growth cones are poor 'tractors,' exerting too little tension to
exploit the available capacity for axonal elongation.
PMID- 9763520
TI - AHA journals lead with definitive new online site
PMID- 9763521
TI - Apoptosis in the atherosclerotic plaque: quantitative and qualitative aspects.
AB - Several laboratories have demonstrated the presence of apoptotic cell death in
atherosclerotic plaques. Apoptosis occurs in at least 2 stages. The final
"execution" phase, which includes DNA fragmentation, is brief ( approximately 6
hours) and irreversible and can be detected by the terminal deoxynucleotidyl
transferase-mediated dUTP nick end labeling (TUNEL) technique. The TUNEL
technique is only selective (rather than specific) for apoptotic nuclei, because
these contain a far greater degree of DNA fragmentation than do nonapoptotic
nuclei. Nonapoptotic cell nuclei that show high levels of RNA synthesis and
splicing can also be labeled. This could explain the large variation in the
reported percentages of TUNEL-positive nuclei in the plaques. Therefore, the
TUNEL technique should be combined with additional techniques, such as markers of
transcription and morphological criteria. Recent studies indicate that human
fatty streaks differ from adaptive intimal thickenings by the presence of cells
containing pro-apoptotic proteins. However, apoptotic cell death is present only
in advanced atherosclerotic plaques that show a dense macrophage infiltration.
This indicates that although both smooth muscle cells and macrophages within the
human fatty streaks become susceptible to apoptosis, additional factors (mainly
macrophage- and lipid-derived factors) are necessary to terminate the cell death
pathway.
PMID- 9763522
TI - Sphingolipids in atherosclerosis and vascular biology.
AB - Sphingolipids and their metabolic products are now known to have second-messenger
functions in a variety of cellular signaling pathways. Lactosylceramide (LacCer),
a glycosphingolipid (GSL) present in vascular cells such as endothelial cells,
smooth muscle cells, macrophages, neutrophils, platelets, and monocytes,
contributes to atherosclerosis. Large amounts of LacCer accumulate in fatty
streaks, intimal plaque, and calcified intimal plaque, along with oxidized low
density lipoproteins (Ox-LDLs), growth factors, and proinflammatory cytokines. A
possible role for LacCer in vascular cell biology was suggested when this GSL was
found to stimulate the proliferation in vitro of aortic smooth muscle cells
(ASMCs). A further link of LacCer in atherosclerosis was uncovered by the finding
that Ox-LDLs stimulated specifically the biosynthesis of LacCer. Ox-LDL
stimulated endogenous synthesis of LacCer by activation of UDP-Gal:GlcCer,beta1
4galtransferase (GalT-2) is an early step in this signaling pathway. In turn,
LacCer serves as a lipid second messenger that orchestrates a signal transduction
pathway, ultimately leading to cell proliferation. This signaling pathway
includes LacCer-mediated activation of NADPH oxidase that produces superoxide.
Such superoxide molecules stimulate the GTP loading of p21(ras). Subsequently,
the kinase cascade (Raf-1, Mek2, and p44MAPK [mitogen-activated protein kinase])
is activated. The phosphorylated form of p44MAPK translocates from the cytoplasm
to the nucleus and engages in c-fos expression, proliferating cell nuclear
antigen (PCNA) such as cyclin activation, and cell proliferation takes place.
Interestingly, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP),
an inhibitor of GalT-2, can abrogate the Ox-LDL-mediated activation of GalT-2,
the signal kinase cascade noted above, as well as cell proliferation. Additional
studies have revealed that LacCer mediates the tumor necrosis factor-alpha (TNF
alpha)-induced nuclear factor-kappaB expression and intercellular adhesion
molecule (ICAM-1) expression in vascular endothelial cells via the redox
dependent transcriptional pathway. LacCer also stimulates the expression of
CD11/CD8, or Mac-1, on the surface of human neutrophils. Collectively, this
phenomenon may contribute to the adhesion of neutrophils or monocytes to the
endothelial cell surface and thus initiate the process of atherosclerosis. In
addition, the LacCer-mediated proliferation of ASMCs may contribute to the
progression of atherosclerosis. On the other hand, programmed cell death
(apoptosis) by proinflammatory cytokines such as TNF-alpha, interleukin-1, and
high concentrations of Ox-LDL occur via activation of a cell membrane-associated
neutral sphingomyelinase (N-SMase). N-SMase hydrolyzes sphingomyelin into
ceramide and phosphocholine. In turn, ceramide or a homologue serves as an
important stress-signaling molecule. Interestingly, an antibody against N-SMase
can abrogate Ox-LDL- and TNF-alpha-induced apoptosis and therefore may be useful
for in vivo studies of apoptosis in experimental animals. Because plaque
stability is an integral aspect of atherosclerosis management, activation of N
SMase and subsequent apoptosis may be vital events in the onset of plaque
rupture, stroke, or heart failure. Interestingly, in human liver cells, N-SMase
action mediates the TNF-alpha-induced maturation of the sterol regulatory-element
binding protein. Moreover, a cell-permeable ceramide can reconstitute the
phenomenon above in a sterol-independent fashion. Such findings may provide new
avenues for therapy for patients with atherosclerosis. The findings described
here indicate an important role for sphingolipids in vascular biology and provide
an exciting opportunity for further research in vascular disease and
atherosclerosis.
PMID- 9763523
TI - Polymorphonuclear leukocytes induce PDGF release from IL-1beta-treated
endothelial cells: role of adhesion molecules and serine proteases.
AB - Polymorphonuclear leukocytes (PMNs) and endothelial cells interact at sites of
vascular injury during inflammatory response and during the development of
atherosclerotic lesions. Such close proximity leads to the modulation of several
of the biological functions of the 2 cell types. Because we have shown previously
that PMNs enhance release of growth factors from resting endothelial cells, we
decided to evaluate whether coincubation of PMNs with interleukin-1beta (IL
1beta)-stimulated human umbilical vein endothelial cells (HUVEC) could further
modulate mitogen release from HUVEC. We found that PMN-HUVEC coincubation
resulted in a 10-fold increase in mitogen release, compared with HUVEC alone
(14+/-6 versus 1.3+/-0.1). When PMNs were incubated with IL-1beta-treated HUVEC,
a further increase in mitogen release (up to 35-fold) was observed. The mitogenic
activity was immunologically related to platelet-derived growth factor (PDGF)
because the activity was abolished by an anti-PDGF antibody. PDGF-AB antigen,
detected in low concentrations in conditioned medium from HUVEC alone, was
increased 4-fold when IL-1beta or PMNs were incubated with HUVEC and dramatically
upregulated (up to 40-fold) when PMNs were cocultured with IL-1beta-treated
HUVEC. The presence of the protease inhibitor eglin C abolished mitogenic
activity generation, suggesting a role for PMN-derived elastase and cathepsin G.
Indeed, purified elastase and cathepsin G mimicked PMN-induced mitogen release
from HUVEC. Because PMNs firmly adhered to IL-1beta-treated HUVEC, we
investigated the role of cell-cell adhesion in mitogen release. Adhesion and PDGF
release were inhibited by approximately 60% in the presence of anti-CD11a/CD18
and anti-intercellular adhesion molecule-1 monoclonal antibodies. This study
suggests a new role for PMNs and their interaction with endothelium in
pathological conditions in which intimal hyperplasia is a common feature.
PMID- 9763525
TI - Impaired insulin-stimulated glucose oxidation and free fatty acid suppression in
patients with familial combined hyperlipidemia: a precursor defect for
dyslipidemia?
AB - Familial combined hyperlipidemia (FCHL) is characterized by hyperlipidemia and
insulin resistance, but intracellular defect in insulin action is unknown.
Therefore, we investigated insulin action by applying the hyperinsulinemic
euglycemic clamp technique with indirect calorimetry in 58 FCHL family members
(28 with FCHL; 30 without dyslipidemia; aged 49+/-12 years; body mass index
[BMI], 25. 2+/-4.0 kg/m2) and in 72 healthy control subjects (aged 54+/-6 years;
BMI, 26.3+/-3.1 kg/m2). In the fasting state, FCHL patients had higher levels of
total cholesterol, total triglycerides, and apolipoprotein B than control
subjects (P<0.001 after adjustment for gender, age, and BMI). During the
euglycemic clamp, FCHL patients had lower rates of glucose oxidation (15.93+/
3.55 versus 19.65+/-4. 60 micromol/kg/min; P=0.001) and higher rates of lipid
oxidation (0. 15+/-0.13 versus 0.01+/-0.25 mg/kg/min; P=0.024), as well as higher
levels of serum-free fatty acids (FFA) (0.24+/-0.17 versus 0.06+/-0. 06 mmol/L;
P<0.001) compared with those of control subjects. Relatives without dyslipidemia
differed similarly from control subjects with respect to rates of glucose and
lipid oxidation and FFA suppression during the hyperinsulinemic clamp. In FCHL
family members, during the euglycemic clamp FFAs correlated negatively with the
rates of glucose oxidation (P<0.001) but not with the rates of glucose
nonoxidation (P=0.408). In FCHL family members without dyslipidemia and in
control subjects, FFAs during the clamp correlated positively with levels of
total triglycerides (P<0.001) and very low density lipoprotein cholesterol
(P=0.008). We conclude that in patients with FCHL, and also in their first-degree
relatives, insulin's suppressive effect on FFA levels is impaired, which may
precede dyslipidemia in FCHL.
PMID- 9763524
TI - Ligand specificity of LOX-1, a novel endothelial receptor for oxidized low
density lipoprotein.
AB - Endothelial dysfunction, or activation, elicited by oxidized low density
lipoprotein (Ox-LDL) and its lipid constituents has been shown to play a key role
in the pathogenesis of atherosclerosis. We recently have identified a novel
receptor for Ox-LDL-designated lectin-like Ox-LDL receptor (LOX-1) in vascular
endothelial cells. To examine ligand specificity of LOX-1, we established CHO
cell lines stably expressing both human and bovine LOX-1 (LOX-1-CHO). LOX-1-CHO
bound and degraded 125I-labeled Ox-LDL but did not significantly degrade 125I
labeled acetylated LDL (Ac-LDL). Fucoidin and maleylated BSA (M-BSA), which
inhibit 125I-Ox-LDL binding to class A scavenger receptors, did not inhibit 125I
Ox-LDL binding or degradation in LOX-1-CHO. Polyinosinic acid and carrageenan, in
contrast, significantly reduced 125I-Ox-LDL binding to LOX-1-CHO by 62% and 60%,
respectively. Delipidated and untreated 125I-Ox-LDL were bound and degraded
equally in LOX-1-CHO; furthermore, excess amounts of unlabeled, delipidated Ox
LDL inhibited binding and degradation of untreated 125I-Ox-LDL. Taken together,
LOX-1 is a receptor for Ox-LDL but not for Ac-LDL. LOX-1 recognizes protein
moiety of Ox-LDL, and its ligand specificity is distinct from other receptors for
Ox-LDL, including class A and B scavenger receptors.
PMID- 9763526
TI - Early atherosclerotic lesions spiraling through the femoral artery.
AB - Atherosclerosis is common in the adductor hiatus region. The aim of this study
was to evaluate atherosclerosis in relation to themorphological structure of the
femoropopliteal region. Two anatomic features are thought to play an important
role in the origin of these lesions: (1) curvature of the vessel, which may lead
to unfavorable local hemodynamic factors that change during leg flexion; and (2)
abrupt changes in stiffness of surrounding tissues of the vessel. The distal part
of 23 postmortem femoral arteries were investigated. Cross sections were obtained
every 1 mm over a length of 100 mm. For each cross section, lesion thickness was
measured at 12 points along the circumference of the vessel. No apparent relation
was found between surrounding structures of the femoral artery and location of
atherosclerotic lesions. Three-dimensional reconstructions showed that
atherosclerotic lesions were spiraling through the artery in 18 of 23 cases.
Spiraling atherosclerotic lesions may be consistent with expected flow patterns
in this part of the femoral artery.
PMID- 9763527
TI - Segregation analysis of plasminogen activator inhibitor-1 and fibrinogen levels
in the NHLBI family heart study.
AB - Elevated plasminogen activator inhibitor-1 (PAI-1) and fibrinogen concentrations
are risk factors for coronary heart disease. We investigated environmental,
familial, and genetic influences on PAI-1 antigen and fibrinogen concentrations
in 2029 adults from 512 randomly ascertained families in 4 US communities. We
used maximum-likelihood segregation analysis to fit several genetic and
nongenetic modes of inheritance to the data to determine whether mendelian
inheritance of a major gene could best explain the familial distributions of
these 2 hemostatic factors. Age- and gender-adjusted familial correlations for
PAI-1 antigen level averaged 0.16 in first-degree relatives (95% CI=0.11 to
0.21); the spouse correlation was positive but not statistically significant
(r=0.10, 95% CI=-0.02 to 0.23). Complex segregation analysis indicated a major
gene associated with higher PAI-1 concentrations in 65% of individuals from these
families. Demographic, anthropometric, lifestyle, and metabolic characteristics
together explained 37% to 47% of the variation in PAI-1 antigen levels, and the
inferred major gene explained an additional 17% of the variance. Positive and
statistically significant age- and gender-adjusted familial correlations in first
degree relatives indicated a possible heritable component influencing plasma
fibrinogen concentration (r=0. 17, 95% CI=0.13 to 0.22); however, segregation
analysis did not provide statistical evidence of a major gene controlling
fibrinogen level. These family data suggest that there are modest familial and
genetic effects on the concentration of PAI-1.
PMID- 9763528
TI - Expression of ACAT-1 protein in human atherosclerotic lesions and cultured human
monocytes-macrophages.
AB - The acyl coenzyme A:cholesterol acyltransferase (ACAT) gene was first cloned in
1993 (Chang et al, J Biol Chem. 1993;268:20747-20755; designated ACAT-1). Using
affinity-purified antibodies raised against the N-terminal portion of human ACAT
1 protein, we performed immunohistochemical localization studies and showed that
the ACAT-1 protein was highly expressed in atherosclerotic lesions of the human
aorta. We also performed cell-specific localization studies using double
immunostaining and showed that ACAT-1 was predominantly expressed in macrophages
but not in smooth muscle cells. We then used a cell culture system in vitro to
monitor the ACAT-1 expression in differentiating monocytes-macrophages. The ACAT
1 protein content increased by up to 10-fold when monocytes spontaneously
differentiated into macrophages. This increase occurred within the first 2 days
of culturing the monocytes and reached a plateau level within 4 days of
culturing, indicating that the increase in ACAT-1 protein content is an early
event during the monocyte differentiation process. The ACAT-1 protein expressed
in the differentiating monocytes-macrophages was shown to be active by enzyme
assay in vitro. The high levels of ACAT-1 present in macrophages maintained in
culture can explain the high ACAT-1 contents found in atherosclerotic lesions.
Our results thus support the idea that ACAT-1 plays an important role in
differentiating monocytes and in forming macrophage foam cells during the
development of human atherosclerosis.
PMID- 9763529
TI - Estradiol suppresses MCP-1 expression In vivo : implications for atherosclerosis.
AB - The mechanisms by which 17beta-estradiol retards atherogenesis are not known. The
adhesion of monocytes to endothelial cells followed by the migration of monocytes
into the artery wall are key cellular events that occur throughout the entire
atherogenic process and may be responsive to estradiol. Monocyte chemoattractant
protein-1 (MCP-1), a chemokine that is expressed in atherosclerotic lesions, is
thought to play a major role in stimulating the migration of blood monocytes into
developing atherosclerotic lesions. We therefore assessed the effects of
estradiol in vivo on MCP-1 protein and mRNA expression in the descending thoracic
aorta of rabbits fed a cholesterol-enriched (0.5%) diet for 6 weeks and in
animals fed normal chow. MCP-1 protein was quantified by Western blot analysis
and monocyte chemotaxis bioassay, and reverse transcription-polymerase chain
reaction was used to ascertain the level of MCP-1 mRNA expression. We observed
that in both ovary-intact and ovariectomized (OVX) animals, MCP-1 protein and
mRNA expression were significantly increased by 6 weeks in animals fed a high
cholesterol diet. The cholesterol-induced increase in MCP-1 protein and mRNA
expression was significantly attenuated in OVX rabbits supplemented with
estradiol pellets (1.5- and 10.0-mg 60-day-release pellets), which yielded a
range of estradiol concentrations encompassing the physiological levels. MCP-1
protein and mRNA expression were increased in normocholesterolemic OVX rabbits
compared with normocholesterolemic ovary-intact animals, and this increase was
prevented in OVX animals supplemented with estradiol pellets. Our observations
indicate that both basal and hypercholesterolemia-induced increases in MCP-1
protein are modulated by physiological concentrations of estradiol.
PMID- 9763530
TI - Hypercholesterolemia enhances oxidant production in mesenteric venules exposed to
Ischemia/Reperfusion.
AB - It has been shown that hypercholesterolemia (HCh) exaggerates the microvascular
dysfunction that is elicited by ischemia and reperfusion (I/R). The objective of
this study was to determine whether oxidants contribute to the exaggerated
inflammatory responses and enhanced albumin leakage observed in HCh rat
mesenteric venules exposed to I/R (10 minutes of ischemia and 30 minutes of
reperfusion). Intravital videomicroscopy was used to quantify the number of
adherent and emigrated leukocytes, albumin extravasation, platelet-leukocyte
aggregation in postcapillary venules, and the degranulation of adjacent mast
cells. Oxidation of the fluorochrome dihydrorhodamine 123 (DHR) was used to
monitor oxidant production by venular endothelium. I/R was shown to elicit an
increased DHR oxidation in venules of both control and HCh rats, with the latter
group exhibiting a significantly larger response. Treatment with either
oxypurinol or superoxide dismutase largely prevented the leukocyte recruitment,
platelet-leukocyte aggregation, mast cell degranulation, and enhanced DHR
oxidation elicited by I/R in HCh rats. The enhanced albumin leakage was reduced
by superoxide dismutase but not by oxypurinol. These results indicate that HCh
amplifies the oxidant stress elicited by I/R and that interventions that blunt
the oxidant stress effectively attenuate the leukocyte, platelet, and mast cell
activation that result from I/R.
PMID- 9763531
TI - Cholesterol metabolism and efflux in human THP-1 macrophages.
AB - This study has investigated in detail factors regulating accumulation,
esterification, and mobilization of cholesterol in human THP-1 macrophages. Human
THP-1 monocytes were differentiated into macrophages and then cholesterol
enriched by exposure to acetylated LDL (AcLDL), together with [3H]free
cholesterol (FC). Although THP-1 macrophages accumulated FC and esterified
cholesterol (EC), assessed by both mass and radioactivity, cellular EC always
demonstrated a much lower specific activity (cpm/ microg) than did cellular FC,
and several potential causes of this finding were investigated. Inhibition of
acyl-CoA:cholesterol acyltransferase (ACAT) during loading decreased cell [3H]EC
by 95+/-1.4% but decreased cell EC mass by only 66.0+/-4.0%, indicating that some
intracellular undegraded AcLDL-derived EC was present in these cells.
Esterification of [3H]oleate to EC in THP-1 cells loaded with AcLDL was 2.0 nmol
x mg-1 x h-1, consistent with previous literature. However, EC, triglyceride, and
phospholipid fractions respectively contained 1.0+/-0.07%, 80.0+/-0.5%, and
18.9+/-0.3% of cell [3H]oleate, indicating triglycerides were much more
metabolically active than EC. In addition, the mass of triglyceride in THP-1
macrophages exceeded that of EC both before and after exposure to AcLDL.
Esterification of nonlipoprotein-derived cholesterol was compared in THP-1 cells
and nonhuman Fu5AH, CHO, and RAW macrophage cells. Whereas the nonhuman cell
lines all esterified over 30% of 2-hydroxypropyl-beta-cyclodextrin (hp-ss-CD)
delivered cholesterol within 6 hours, THP-1 cells esterified <8.0% of
incorporated cholesterol. Kinetics of cholesterol efflux from AcLDL-loaded THP-1
cells were first investigated after loading with only FC, and interactions
between efflux and EC hydrolysis were further assessed after loading cells with
both EC and FC. Over 24 hours, human apolipoprotein (apo) A-I, apoHDL
reconstituted with phosphatidylcholine, and HDL3 respectively removed 46.6+/
3.7%, 61. 3+/-3.4%, and 76.4+/-10.1% of [3H]FC from FC-enriched THP-1 cells.
Cholesterol efflux to apoA-I was saturated by 24 hours and was enhanced by using
apoA-I-phospholipid instead of pure apoA-I. Kinetic modeling identified that 97%
of effluxed FC derived from a slow pool, with a T1/2 ranging from 27.7 hours for
HDL to 69.3 hours for apoA-I. Although efflux enhanced net clearance of EC,
hydrolysis of EC during concurrent inhibition of ACAT was unaffected by
cholesterol efflux. Supplementation of THP-1 cultures with cAMP to stimulate
hormone-sensitive lipase did not significantly enhance net hydrolysis of EC or
cholesterol efflux. In conclusion, human THP-1 macrophages contain a large and
metabolically active pool of triglyceride and a relatively inactive pool of EC.
The low specific activity of EC relative to FC is contributed to by reduced
esterification of FC, slow hydrolysis of EC, and accumulated lipoprotein EC. The
relative inactivity of the EC pool may further contribute to already impaired
cholesterol efflux from these cells. Net cholesterol efflux from human
macrophages is achieved by pure apoA-I and is substantially further enhanced by
the presence of phospholipid in acceptor particles.
PMID- 9763532
TI - Mutations in the low-density lipoprotein receptor gene in Chinese familial
hypercholesterolemia patients.
AB - It has been reported that in China, patients with heterozygous familial
hypercholesterolemia (FH) may go unrecognized because they do not have xanthomata
or premature coronary heart disease and their LDL cholesterol levels are lower
than those in their Western counterparts. However, in the Chinese patients in
Hong Kong, heterozygous FH appears to manifest in a way similar to that seen in
Western countries or Japan. We studied sequence variations in the promoter and
coding regions of the 18 exons of the LDL receptor gene in 30 Chinese FH
patients. Eighteen mutations were identified in 21 patients scattered in the
promoter and 10 exons. Eleven of them were first found in this study. We also
found 6 polymorphisms with allelic frequencies different from those in whites but
similar to the Japanese, indicating some isolation between white and Oriental
populations. A total of 29 mutations in the LDL receptor gene are now known in
the Chinese. There is no definite common mutation due to a founder effect.
Meanwhile, there were no detectable LDL receptor gene mutations in 9 clinically
diagnosed FH patients in whom the R3500Q mutation in apolipoprotein B had also
been excluded. The gene defects leading to the FH phenotype in these patients may
occur somewhere else in the apolipoprotein B or other related genes, or even in
the noncoding sequences of the LDL receptor gene.
PMID- 9763533
TI - Postprandial lipemic response is modified by the polymorphism at codon 54 of the
fatty acid-binding protein 2 gene.
AB - Polymorphism of the fatty acid-binding protein 2 (FABP2) gene has been shown to
affect the affinity of intestinal FABP for fatty acids. This could cause changes
in postprandial triglyceride metabolism. In the present study, postprandial
lipemia was studied in normotriglyceridemic subjects with genetic variation in
the FABP2 gene. Oral fat-loading tests were performed in 8 subjects homozygous
for the Thr-encoding allele at codon 54 of the FABP2 gene and in 7 subjects
homozygous for the Ala-encoding allele (wild type). There were no significant
differences between these 2 groups in age, body mass index, fasting plasma
triglyceride and cholesterol levels, or fasting glucose and insulin levels. The
increase of plasma triglyceride concentration after the fat test meal was
significantly greater in subjects who were homozygous for the Thr-54 allele (area
under the response curve, 4.27+/-1.31 versus 2.49+/-1.18 mmol/L x h-1, P=0.04).
The difference was seen in both chylomicron (2.51+/-0. 98 versus 1.41+/-0.74
mmol/L x h-1, P=0.03) and very low-density lipoprotein triglycerides (1.57+/-0.77
versus 0.99+/-0.40 mmol/L x h-1, P=0.04). Postprandial triglyceride response
correlated with fasting triglycerides in the Ala-54 homozygotes (r=0.79, P=0.05)
but not in the Thr-54 homozygotes (r=0.09), who showed a strong correlation
between triglyceride and insulin responses (r=0.83, P=0. 02). With reservations
related to a small number of subjects studied, these results indicate that the
Thr-encoding allele of the FABP2 gene is associated with increased postprandial
lipemia. The lipemic response was associated with postprandial insulin response,
suggesting that in the Thr-54 homozygotes, altered postprandial lipemia may also
modify insulin action or vice versa.
PMID- 9763534
TI - The gln-Arg192 polymorphism of human paraoxonase gene is not associated with
coronary artery disease in italian patients.
AB - Serum paraoxonase (PON) is an HDL-bound enzyme protecting LDL from oxidation. A
common polymorphism of the paraoxonase gene (PON1) involving a Gln-to-Arg
interchange at position 192 has been demonstrated to modulate PON activity toward
paraoxon, a nonphysiological substrate; Arg192 (allele B) is associated with
higher activity than Gln192 (allele A). This polymorphism has been proposed as a
genetic marker of risk for coronary artery disease (CAD). However, the
relationships between codon 192 PON1 genotypes, coronary atherosclerosis, and the
occurrence of myocardial infarction (MI) are still controversial. PON1 genotypes
were determined in 472 consecutive subjects (>40 years old) who underwent
coronary angiography. CAD (>50% stenosis) was detected in 310 subjects (CAD+);
162 subjects with <10% stenosis served as controls (CAD-). We also evaluated 204
randomly selected individuals as population controls. PON1 genotypes were
determined by PCR and AlwI restriction enzyme digestion. Frequencies of alleles A
and B were 0. 70 and 0.30 in angiographically assessed subjects and 0.73 and 0.27
in population controls, respectively (chi2=2.0; P<0.3). Distribution of PON1
genotypes in CAD+ were not significantly different from those in CAD- (chi2=2.10;
P<0.3). Similarly, no differences were observed in the subgroup of CAD+ with MI
nor in that at higher oxidative risk (smokers and/or diabetics). After
controlling for other coronary risk factors, no association was found between
PON1 alleles and the presence of CAD. PON1 AA genotype was associated with
reduced concentration of apolipoprotein B-containing triglyceride-rich
lipoproteins. This study did not provide evidence of a significant association
between codon 192 PON1 genotypes and coronary atherosclerosis in Italian
patients. However, it did confirm that the PON1 low-activity allele is associated
with a less atherogenic lipid profile.
PMID- 9763535
TI - Paraoxonase active site required for protection against LDL oxidation involves
its free sulfhydryl group and is different from that required for its
arylesterase/paraoxonase activities: selective action of human paraoxonase
allozymes Q and R.
AB - Human serum paraoxonase (PON 1) exists in 2 major polymorphic forms (Q and R),
which differ in the amino acid at position 191 (glutamine and arginine,
respectively). These PON allozymes hydrolyze organophosphates and aromatic
esters, and both also protect LDL from copper ion-induced oxidation. We have
compared purified serum PONs of both forms and evaluated their effects on LDL
oxidation, in respect to their arylesterase/paraoxonase activities. Copper ion
induced LDL oxidation, measured by the production of peroxides and aldehydes
after 4 hours of incubation, were reduced up to 61% and 58%, respectively, by PON
Q, but only up to 46% and 38%, respectively, by an equivalent concentration of
PON R. These phenomena were PON-concentration dependent. Recombinant PON Q and
PON R demonstrated similar patterns to that shown for the purified serum
allozymes. PON Q and PON R differences in protection of LDL against oxidation
were further evaluated in the presence of glutathione peroxidase (GPx). GPx (0.1
U/mL) alone reduced copper ion-induced LDL oxidation by 20% after 4 hours of
incubation. The addition of PON R to the above system resulted in an additive
inhibitory effect on LDL oxidation, whereas PON Q had no such additive effect.
The 2 PON allozymes also differed by their ability to inhibit initiation, as well
as propagation, of LDL oxidation. PON Q was more efficient in blocking LDL
oxidation if added when oxidation was initiated, whereas PON R was more potent
when added 1 hour after the initiation of LDL oxidation. These data suggest that
the 2 allozymes act on different substrates. Both PON allozymes were also able to
reduce the oxidation of phospholipids and cholesteryl ester. PON Q arylesterase
activity was reduced after 4 hours of LDL oxidation by only 28%, whereas the
arylesterase activity of PON R was reduced by up to 55%. Inactivation of the
calcium-dependent PON arylesterase activity by using the metal chelator EDTA, or
by calcium ion removal on a Chelex column, did not alter PON's ability to inhibit
LDL oxidation. However, blockage of the PON free sulfhydryl group at position 283
with p-hydroxymercuribenzoate inhibited both its arylesterase activity and its
protection of LDL from oxidation. Recombinant PON mutants in which the PON free
sulfhydryl group was replaced by either alanine or serine were no longer able to
protect against LDL oxidation, even though they retained paraoxonase and
arylesterase activities. Overall, these studies demonstrate that PON's
arylesterase/paraoxonase activities and the protection against LDL oxidation do
not involve the active site on the enzyme in exactly the same way, and PON's
ability to protect LDL from oxidation requires the cysteine residue at position
283.
PMID- 9763536
TI - Matrix metalloproteinase-2 production and its binding to the matrix are increased
in abdominal aortic aneurysms.
AB - Degradation of the elastic media is a hallmark of abdominal aortic aneurysms
(AAAs). We examined the expression of 2 elastolytic matrix metalloproteinases
(MMPs), MMP-2 and MMP-9, in AAA aortic tissues compared with those from
atherosclerotic occlusive disease (AOD) and nondiseased control tissues.
Quantitative competitive reverse transcription-polymerase chain reaction and
gelatin zymography showed increased MMP-9 mRNA and protein in both AAA and AOD
tissues compared with those in control tissue, but there was no significant
difference between AAA and AOD. In contrast, MMP-2 mRNA and protein levels were
significantly higher in AAA than in AOD or control tissues. Sequential extraction
of the MMPs from the aortic tissue with a physiological salt solution, 2%
dimethylsulfoxide (DMSO), and 10 mol/L urea showed that large amounts of MMP-2
and MMP-9 were bound to the matrix. The most conspicuous finding was that the
levels of MMP-2 were significantly elevated in the DMSO fraction in AAA tissues
compared with AOD and control tissues. In addition, a large portion of MMP-2
found in the DMSO and urea fractions was in the active 62-kDa form, indicating
that the precursor of MMP-2 in AAA is largely activated locally and binds to the
tissue matrix tightly. By immunolocalization, MMP-9 was found to be primarily
produced by macrophages and MMP-2 by mesenchymal cells. The production of MMP-2
was prominent when mesenchymal cells were surrounded by inflammatory cells,
suggesting paracrine modulation of MMP-2 expression in AAAs. These observations
emphasize that MMP-2 participates in the progression of AAAs by degrading aortic
tissue matrix components.
PMID- 9763537
TI - Concentration of endogenous tPA antigen in coronary artery disease: relation to
thrombotic events, aspirin treatment, hyperlipidemia, and multivessel disease.
AB - Tissue plasminogen activator (tPA) is the major plasminogen activator responsible
for dissolving blood clots found in blood vessels. However, elevated
concentrations of tPA antigen were found to be related to adverse events in
patients with coronary artery disease (CAD). Considerable controversy about the
significance of these results exists. The goal of this cross-sectional study was
to identify independent determinants for tPA antigen concentrations in patients
with CAD, to possibly clarify the above paradoxical relationship. The baseline
tPA antigen concentrations of 366 patients with angiographic evidence of coronary
sclerosis were determined. Univariate analysis showed that age (P=0.013),
angiographic extent of disease (P<0.001), presence of angina at rest (P<0.001),
diabetes mellitus (P=0.004), hypercholesterolemia (P=0. 045),
hypertriglyceridemia (P=0.015), and chronic intake of nitrates (P<0.001) were
significantly and positively related to tPA antigen concentration, while the
chronic intake of aspirin was inversely related to tPA antigen (P<0.001). In
addition, plasminogen activator inhibitor type 1 (PAI-1) activity was found to be
significantly and positively associated with tPA antigen concentration (P<0.001).
A multivariate analysis identified chronic low-dose aspirin therapy (P<0.001),
PAI-1 activity (P<0.001), hypertriglyceridemia (P=0.005), the type of angina
(P=0.026), multivessel disease (P=0.041), and hypercholesterolemia (P=0.043) as
significant and independent determinants of tPA antigen. While
hypertriglyceridemia and hypercholesterolemia both are related to the underlying
disease, the type of angina and the number of involved vessels are linked to the
severity and extent of disease, and all of them are indicators of a prothrombotic
state found during the progression of CAD. In contrary, low-dose aspirin rather
would decrease the likelihood of thrombotic events. The relation of tPA antigen
to PAI-1 activity furthermore underlines the relation between tPA antigen
concentration and a prothrombotic state. Therefore, the positive or-in case of
aspirin therapy-negative correlation of these parameters with tPA antigen
concentration would indicate that thrombus formation and simultaneous endothelial
cell activation might be major determinants for tPA antigen concentration in CAD.
PMID- 9763538
TI - Combination of fosinopril and pravastatin decreases platelet response to thrombin
receptor agonist in monkeys.
AB - Both angiotensin-converting enzyme (ACE) inhibitors and 3-hydroxy-3
methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been shown to
decrease cardiovascular morbidity and mortality. Results from clinical trials
have suggested that HMG-CoA reductase inhibition might exert a beneficial effect
independent of its lipid-lowering effect, and ACE inhibition may exert a benefit
independent of blood-pressure lowering. To test the hypothesis that such an
effect might be mediated by alteration in platelet reactivity, we studied 55
monkeys receiving both, 1, or neither of the ACE inhibitor fosinopril and the HMG
CoA reductase inhibitor pravastatin. Platelet responsiveness to collagen and to
the thrombin receptor agonist (TRA) SFLRRN-NH2 was determined by aggregometry.
For each agonist, the maximum rate and extent of aggregation were measured for
each dose, and the concentration required for half-maximal response (C50) was
determined. Each drug, when given alone, slightly decreased the dose of agonist
required to produce 50% response in the rate and extent of platelet aggregation
relative to control. The combination of the 2 drugs, however, produced a
significant increase in the dose of TRA required to produce 50% response in the
rate and extent of aggregation relative to either drug alone or the control
group. This was not true for collagen. The magnitude of the change relative to
the control group, 47% for rate and 30% for extent of aggregation, could confer
considerable protection by changing the threshold for thrombin-induced platelet
aggregation and, thus, decrease thrombosis.
PMID- 9763539
TI - In vitro-differentiated embryonic stem cell macrophages: a model system for
studying atherosclerosis-associated macrophage functions.
AB - Monocytes/macrophages (Mo) appear to play a critical role in the initiation and
progression of atherosclerotic lesions. In this study, we characterized in vitro
differentiated embryonic stem (ES) cell macrophages as a model system for
studying atherosclerosis-associated Mo functions. Using immunofluorescence
staining and Western analysis, we demonstrate that ES Mo express typical
macrophage cell surface markers, as well as the known receptors for modified
forms of low density lipoprotein (LDL), including the Mo scavenger receptors (SR
A type I and type II), CD36, and CD68. Differentiated ES Mo specifically bind and
degrade 125I-labeled acetylated LDL with high affinity, and their incubation with
acetylated LDL (15 microg/mL) for 48 hours produces characteristic "foamy" Mo, as
visualized by oil red O staining. ES Mo also express matrix-degrading
metalloproteinases (MMP-3, MMP-9), which have been implicated in collagen
breakdown in the fibrous cap of atherosclerotic plaques, and secrete cytokines
(tumor necrosis factor-alpha, interleukin-6) in response to inflammatory stimuli.
Transfection experiments, using a green fluorescent protein reporter gene, driven
by the myeloid-specific promoter, CD11b, demonstrated that ES Mo can also be used
to study macrophage-restricted gene expression in vitro. Taken together, these
data demonstrate that ES Mo exhibit many properties typical of arterial lesion
macrophages. Its ease of genetic manipulation makes it an attractive system for
investigations of macrophage functions in vitro.
PMID- 9763540
TI - Differential induction of cyclooxygenase-2 in human arterial and venous smooth
muscle: role of endogenous prostanoids.
AB - Two isoforms of cyclooxygenase (COX) have been identified: a constitutive isoform
(COX-1), found in abundance in platelets and the vascular endothelium, and an
"inflammatory" cytokine-inducible isoform (COX-2). Because COX metabolites
regulate vascular smooth muscle cell (SMC) function and the interaction between
the vessel and circulating components, we have investigated the possibility that
COX-2 can be induced in human arterial or venous SMC. Untreated venous or
arterial cells contained undetectable levels of COX-1 or COX-2 and released low
levels of metabolites. After stimulation with interleukin-1beta, tumor necrosis
factor-alpha, interferon-gamma, and bacterial lipopolysaccharide, both venous and
arterial SMC expressed COX-2 protein and released increased amounts of
prostaglandins. In addition, the induced release of PGE2 was inhibited by the COX
2-selective inhibitor, L-745,337. When cells were treated with the mixture of
cytokines, venous SMC expressed greater amounts of COX-2 protein and released
more prostaglandins than arterial SMC. Furthermore, when COX-2 activity was
blocked by L-745,337, COX-2 expression in arterial SMC, but not in venous SMC,
increased. Thus, this article describes, for the first time, that COX-2 is
expressed in greater amounts in venous SMC than in arterial SMC. Moreover, we
show that this "differential induction" is due to a negative-feedback pathway for
COX-2 expression in arterial SMC but not in venous SMC. The ability of COX-2
activity to limit COX-2 expression in some cells but not others may contribute to
the highly developed mechanisms involved in prostanoid release.
PMID- 9763541
TI - Vitamin C protects human arterial smooth muscle cells against atherogenic
lipoproteins: effects of antioxidant vitamins C and E on oxidized LDL-induced
adaptive increases in cystine transport and glutathione.
AB - Glutathione (GSH) plays a key role in cellular antioxidant defenses by scavenging
reactive oxygen species and reducing lipid peroxides. Intracellular GSH levels
are regulated by transport of its precursor L-cystine via system xc-, which can
be induced by oxidant stress. As oxidatively modified low density lipoproteins
(LDLs) contribute to impaired vascular reactivity and the formation of
atherosclerotic lesions, we have examined the effects of oxidized LDL and the
antioxidant vitamins C and E on the L-cystine-GSH pathway in human umbilical
artery smooth muscle cells (HUASMCs). Oxidized LDL, but not native LDL, elevated
intracellular GSH levels and L-cystine transport via system xc- in a time
dependent (up to 24 hours) and dose-dependent (10 to 100 microg x mL-1) manner.
These increases were dependent on protein synthesis and the extent of LDL
oxidation, but the induction of L-cystine transport activity was independent of
GSH synthesis. Pretreatment of HUASMCs for 24 hours with vitamin E (100
micromol/L) attenuated oxidized LDL-mediated increases in GSH, whereas
pretreatment with vitamin C depressed basal levels and abolished oxidized LDL
induced increases in GSH and L-cystine transport in a time-dependent (3 to 24
hours) and dose-dependent (10 to 100 micromol/L) manner. Pretreatment of cells
with dehydroascorbate had no effect on oxidized LDL-mediated increases in L
cystine transport and only marginally attenuated increases in GSH. Our findings
provide the first evidence that vitamin C spares endogenous adaptive antioxidant
responses in human vascular smooth muscle cells exposed to atherogenic oxidized
LDL.
PMID- 9763542
TI - Adhesion receptors as regulators of the hematopoietic process.
PMID- 9763543
TI - The sialomucin CD164 (MGC-24v) is an adhesive glycoprotein expressed by human
hematopoietic progenitors and bone marrow stromal cells that serves as a potent
negative regulator of hematopoiesis.
AB - Mucin-like molecules represent an emerging family of cell surface glycoproteins
expressed by cells of the hematopoietic system. We report the isolation of a cDNA
clone that encodes a novel transmembrane isoform of the mucin-like glycoprotein
MGC-24, expressed by both hematopoietic progenitor cells and elements of the bone
marrow (BM) stroma. This molecule was clustered as CD164 at the recent workshop
on human leukocyte differentiation antigens. CD164 was identified using a
retroviral expression cloning strategy and two novel monoclonal antibody (MoAb)
reagents, 103B2/9E10 and 105.A5. Both antibodies detected CD164/MGC-24v protein
expression by BM stroma and subpopulations of the CD34(+) cells, which include
the majority of clonogenic myeloid (colony-forming unit-granulocyte-macrophage
[CFU-GM]) and erythroid (blast-forming unit-erythroid [BFU-E]) progenitors and
the hierarchically more primitive precursors (pre-CFU). Biochemical and
functional characterization of CD164 showed that this protein represents a
homodimeric molecule of approximately 160 kD. Functional studies demonstrate a
role for CD164 in the adhesion of hematopoietic progenitor cells to BM stromal
cells in vitro. Moreover, antibody ligation of CD164 on primitive hematopoietic
progenitor cells characterized by the cell surface phenotype CD34(BRIGHT)CD38(-)
results in the decreased recruitment of these cells into cell cycle, suggesting
that CD164 represents a potent signaling molecule with the capacity to suppress
hematopoietic cell proliferation.
PMID- 9763544
TI - Cyclical neutropenia and other periodic hematological disorders: a review of
mechanisms and mathematical models.
AB - Although all blood cells are derived from hematopoietic stem cells, the
regulation of this production system is only partially understood. Negative
feedback control mediated by erythropoietin and thrombopoietin regulates
erythrocyte and platelet production, respectively, but the regulation of
leukocyte levels is less well understood. The local regulatory mechanisms within
the hematopoietic stem cells are also not well characterized at this point.
Because of their dynamic character, cyclical neutropenia and other periodic
hematological disorders offer a rare opportunity to more fully understand the
nature of these regulatory processes. We review the salient clinical and
laboratory features of cyclical neutropenia (and the less common disorders
periodic chronic myelogenous leukemia, periodic auto-immune hemolytic anemia,
polycythemia vera, aplastic anemia, and cyclical thrombocytopenia) and the
insight into these diseases afforded by mathematical modeling. We argue that the
available evidence indicates that the locus of the defect in most of these
dynamic diseases is at the stem cell level (auto-immune hemolytic anemia and
cyclical thrombocytopenia seem to be the exceptions). Abnormal responses to
growth factors or accelerated cell loss through apoptosis may play an important
role in the genesis of these disorders.
PMID- 9763545
TI - Cell cycle-related changes in repopulating capacity of human mobilized peripheral
blood CD34(+) cells in non-obese diabetic/severe combined immune-deficient mice.
AB - Most primitive hematopoietic progenitor cells reside in vivo within the G0/G1
phase of the cell cycle. By simultaneous DNA/RNA staining it is possible to
distinguish G0 and G1 states and to isolate cells in defined phases of the cell
cycle. We report here the use of cell cycle fractionation to separate human
mobilized peripheral blood (MPB) CD34(+) cells capable of repopulating the bone
marrow (BM) of non-obese diabetic/severe combined immune-deficient (NOD/SCID)
mice. In freshly isolated MPB, repopulating cells were predominant within the G0
phase, because transplantation of CD34(+) cells residing in G0 (G0CD34(+))
resulted on average in a 16.6- +/- 3.2-fold higher BM chimerism than infusion of
equal numbers of CD34(+) cells isolated in G1. We then investigated the effect of
ex vivo cell cycle progression, in the absence of cell division, on engraftment
capacity. Freshly isolated G0CD34(+) cells were activated by interleukin-3 (IL
3), stem cell factor (SCF), and flt3-ligand (FL) for a 36-hour incubation period
during which a fraction of cells progressed from G0 into G1 but did not complete
a cell cycle. The repopulating capacity of stimulated cells was markedly
diminished compared with that of unmanipulated G0CD34(+) cells. Cells that
remained in G0 during the 36-hour incubation period and those that traversed into
G1 were sorted and assayed separately in NOD/SCID recipients. The repopulating
ability of cells remaining in G0 was insignificantly reduced compared with that
of unstimulated G0CD34(+) cells. On the contrary, CD34(+) cells traversing from
G0 into G1 were largely depleted of repopulating capacity. Similar results were
obtained when G0CD34(+) cells were activated by the combination of thrombopoietin
SCF-FL. These studies provide direct evidence of the quiescent nature of cells
capable of repopulating the BM of NOD/SCID mice. Furthermore, these data also
demonstrate that G0-G1 progression in vitro is associated with a decrease in
engraftment capacity.
PMID- 9763546
TI - Integrins involved in the adhesion of megakaryocytes to fibronectin and
fibrinogen.
AB - We studied integrins involved in the adhesion of resting and activated
megakaryocytes (MK) to fibronectin (FN) and fibrinogen (FGN). Guinea pig MK were
isolated and in some experiments were activated by thrombin. MK adhering to FN or
FGN coated on coverslips were quantitated by a computerized image analysis
program. The binding of soluble human FN to MK was detected by Western blotting.
Anti-integrin antibodies, disintegrins, and cyclic RGD peptides were used to
identify integrins involved in the adhesion of MK to FN or FGN. Resting MK
adhered to coverslips with immobilized FN. The adhesion of MK to FN was primarily
inhibited by an anti-alpha5 antibody and EMF-10, a distintegrin highly specific
for alpha5 beta1. However, the adhesion of MK to FN was not blocked by agents
that inhibit alphaIIb beta3, alphav beta3 or alpha4 beta1. A beta1 activating
antibody increased the number of MK bound to FN due to the activation of alpha5
beta1. The binding of soluble FN was also primarily inhibited by agents that
block alpha5 beta1. Resting MK did not adhere to FGN. However, MK activated by
thrombin did adhere to FGN. This binding was mediated by alphaIIb beta3, because
binding was inhibited by bitistatin, a disintegrin, and a cyclic RGD peptide that
are known to block this integrin. The binding of thrombin-activated MK to FN was
mediated by both alpha5 beta1 and alphaIIb beta3 based on the additive effect of
agents that inhibit these integrins. The study indicates that resting MK bind to
FN but not to FGN and that alpha5 beta1 is the major integrin involved in the
binding of MK to FN. Activated MK bind to FGN primarily by alphaIIb beta3.
However, the binding of activated MK to FN is due to both alpha5 beta1 and
alphaIIb beta3. The demonstration that alpha5 beta1 and that alphaIIb beta3 are
involved in MK adhesion indicates that these integrins may have a role in MK
maturation and platelet production.
PMID- 9763547
TI - Attenuated hematopoietic response to granulocyte-macrophage colony-stimulating
factor in patients with acquired pulmonary alveolar proteinosis.
AB - The pathogenesis of acquired pulmonary alveolar proteinosis (PAP), a rare lung
disease characterized by excessive surfactant accumulation within the alveolar
space, remains obscure. Gene-targeted mice lacking the hematopoietic growth
factor granulocyte-macrophage colony-stimulating factor (GM-CSF) or the signal
transducing beta-common chain of the GM-CSF receptor have impaired surfactant
clearance and pulmonary pathology resembling human PAP. We therefore investigated
the hematopoietic effects of GM-CSF in patients with PAP. The hematologic
response of 5 infants with congenital PAP to 5 microgram/kg/d was of normal
magnitude. By contrast, despite normal expression of GM-CSF receptor alpha- and
beta-common chains on peripheral blood myelomonocytic cells (n = 6) and normal
binding affinity of bone marrow mononuclear cells for GM-CSF (n = 3), each of the
12 patients with acquired PAP treated displayed impaired responses to GM-CSF; 5
microgram/kg/d produced only minor eosinophilia, and doses of 7.5 to 20
microgram/kg were required to induce >/=1.5-fold neutrophil increments in the 3
patients who underwent dose-escalation. However, neutrophilic responses to 5
microgram/kg granulocyte colony-stimulating factor (G-CSF) were normal (n = 4).
In vitro, the proportion of hematopoietic progenitors responsive to GM-CSF (16.1%
+/- 8.9%; P = .042) or interleukin-3 (IL-3; 19.3% +/- 7.7%; P = .063), both of
which utilize the beta-common chain of the GM-CSF receptor complex, were reduced
among patients with acquired PAP (n = 4) compared with normal bone marrow donor
controls (47.2% +/- 25.9% and 40.9% +/- 18.6%, respectively). In the one
individual who had complete resolution of lung disease during the period of
study, this was temporally associated with correction of this defective in vitro
response to GM-CSF and IL-3 on serial assessment. These data establish that
patients with acquired PAP have an associated impaired responsiveness to GM-CSF
that is potentially pathogenic in the development of their lung disease. Based on
these observations, we propose a model of the pathogenesis of acquired PAP that
suggests the disease arises as a consequence of an acquired clonal disorder
within the hematopoietic progenitor cell compartment.
PMID- 9763548
TI - Divergent effects of interleukin-4 and interferon-gamma on macrophage-derived
chemokine production: an amplification circuit of polarized T helper 2 responses.
AB - Macrophage-derived chemokine (MDC) is a CC chemokine that recognizes the CCR4
receptor and is selective for T helper 2 (Th2) versus T helper 1 (Th1) cells. The
present study was designed to investigate the effect of the prototypic Th2/Th1
cytokines, interleukin-4 (IL-4) and interferon-gamma (IFN-gamma), on the
production of MDC by human monocytes. IL-4 and IL-13 caused a time-dependent
(plateau at 24 hours) and concentration-dependent (EC50 2 and 10 ng/mL,
respectively) increase of MDC mRNA levels in monocytes. Increased expression of
MDC mRNA was associated with protein release in the supernatant. MDC expression
and production induced by IL-4 and IL-13 were inhibited by IFN-gamma. IFN-gamma
also suppressed the constitutive expression of MDC in mature macrophages and
dendritic cells. These results delineate an amplification loop of polarized Th2
responses based on differential regulation of MDC production by IL-4 and IL-13
versus IFN-gamma and on the selectivity of this chemokine for polarized Th2
cells.
PMID- 9763549
TI - Activated endothelial cells induce apoptosis in leukemic cells by endothelial
interleukin-8.
AB - Tumor cells are eradicated by several systems, including Fas ligand-Fas and tumor
necrosis factor (TNF)-tumor necrosis factor receptor (TNFR). In the previous
study, we purified an apoptosis-inducing factor (AIF) to homogeneity from a
medium conditioned by PDBu-treated HL-60 cells. N-terminal sequence analysis
showed that AIF is identical to endothelial interleukin-8 (IL-8). A novel
apoptosis system, in which endothelial cells participate via endothelial IL-8
release, is identified here. Human umbilical vein cells (VE cells) produce and
secrete IL-8 by stimulation of IL-1alpha and TNF-alpha. Endothelial IL-8, which
is secreted from VE cells by stimulation of IL-1alpha and TNF-alpha , induces
apoptosis in myelogenous leukemia cell line K562 cells. Monocyte-derived IL-8
could not induce apoptosis in K562 cells. Moreover, interaction between VE cells
and K562 cells induces the release of endothelial IL-8 from VE cells, and the
attached K562 cells undergo apoptosis. Moreover, interactions between VE cell and
other cell lines, such as HL-60, U937, Jurkat, and Daudi, induce the secretion of
endothelial IL-8 and the induction of apoptosis in cell lines. Endothelial IL-8
significantly inhibits tumor growth of intraperitoneal and subcutaneous tumor
mass of K562 cells and induces apoptosis in their cells in vivo. Endothelial IL-8
plays an important role in apoptosis involving endothelial cells, which may
provide us with a new therapy for hematological malignancies.
PMID- 9763550
TI - Molecular and serological examination of the relationship of human herpesvirus 8
to multiple myeloma: orf 26 sequences in bone marrow stroma are not restricted to
myeloma patients and other regions of the genome are not detected.
AB - Human herpesvirus 8 (HHV-8) genomic sequences were recently detected by
polymerase chain reaction (PCR) and in situ hybridization in bone marrow stromal
cells grown from multiple myeloma (MM) patients, but not in cells from control
subjects (Rettig et al, Science 276:1851, 1997). We sought to confirm these
observations in our own group of MM patients (n = 30). DNA was extracted from
adherent stromal cells grown under varying conditions and assayed for HHV-8
sequence using PCR to amplify the orf 26 (KS330) sequence (Chang et al, Science
266:1865, 1997), as initially reported. Samples from human control subjects (n =
25) were concurrently extracted and analyzed. After 30 cycles of amplification,
we did not detect any positive samples. In a more sensitive nested PCR, samples
from 18 of 30 (60%) MM patients were positive, at about the limit of detection,
but orf 26 sequence was also amplified from 11 of 25 (44%) human control samples.
However, PCR amplification from other regions of the viral genome (orf 72 and orf
75) was uniformly negative for all MM and control samples, despite equivalent
sensitivity. Additionally, all sera from MM patients were negative for HHV-8 IgG
by immunofluorescence. Our data do not support a role of HHV-8 in the etiology of
MM but may suggest the presence of a related (KS330-containing) virus in MM
patients and in some control subjects. This is a US government work. There are no
restrictions on its use.
PMID- 9763551
TI - The cryptic inv(2)(p23q35) defines a new molecular genetic subtype of ALK
positive anaplastic large-cell lymphoma.
AB - Recently, a distinctive entity characterized by expression of the anaplastic
lymphoma kinase (ALK) protein [most frequently due to the t(2;5)(p23;q35)
associated NPM-ALK fusion] has emerged within the heterogenous group of non
Hodgkin's lymphomas (NHL) classified as anaplastic large-cell lymphoma (ALCL).
Sporadic variant 2p23/ALK abnormalities identified in ALK-positive ALCL indicate
that genes other than NPM may also be involved in the deregulation of ALK and
lymphomagenesis. We report here three cases with an inv(2)(p23q35) detected by
fluorescence in situ hybridization (FISH) in young male patients with ALK
positive ALCL. In contrast to ALCL cases with the classical t(2;5)(p23;q35) that
usually show both cytoplasmic and nuclear or predominantly nuclear alone
localization of the NPM-ALK chimeric product, in all three cases with an
inv(2)(p23q35) the ALK protein accumulated in the cytoplasm only, supporting the
previous assumption that the oncogenic potential of ALK may not be dependent on
its nuclear localization. As the first step to identify the ALK partner gene
involved in the inv(2)(p23q35), we performed extensive FISH studies and
demonstrated that the 2q35 breakpoint occurred within the 1,750-kb region
contained within the 914E7 YAC. Moreover, a striking association of the
inv(2)(p23q35) with a secondary chromosomal change, viz,
ider(2)(q10)inv(2)(p23q35), carrying two additional copies of the putative ALK
related fusion gene, was found in all three patients, suggesting that, in
contrast to the standard t(2;5)/NPM-ALK fusion, multiple copies of the putative
2q35-ALK chimeric gene may be required for efficient tumor development. In
summary, we demonstrate that the inv(2)(p23q35), a variant of the
t(2;5)(p23;q35), is a recurrent chromosomal abnormality in ALK-positive ALCL, the
further characterization of which should provide new insight into the
pathogenesis of these lymphomas.
PMID- 9763552
TI - Antithrombins Wibble and Wobble (T85M/K): archetypal conformational diseases with
in vivo latent-transition, thrombosis, and heparin activation.
AB - The inherent variability of conformational diseases is demonstrated by two
families with different mutations of the same conserved aminoacid in
antithrombin. Threonine 85 underlies the opening of the main beta-sheet of the
molecule and its replacement, by the polar lysine, in antithrombin Wobble,
resulted in a plasma deficiency of antithrombin with an uncharacteristically
severe onset of thrombosis at 10 years of age, whereas the replacement of the
same residue by a nonpolar methionine, antithrombin Wibble, gave near-normal
levels of plasma antithrombin and more typical adult thromboembolic disease.
Isolated antithrombin Wibble had a decreased thermal stability (Tm 56.2, normal
57.6 degreesC) but was fully stabilized by the heparin pentasaccharide (Tm 71.8,
normal 71.0 degreesC), indicating that the prime abnormality is a laxity in the
transition of the main sheet of the molecule from the 5- to 6-stranded form, as
was confirmed by the ready conversion of antithrombin Wibble to the 6-stranded
latent form on incubation. That this transition can occur in vivo was shown by
the finding of nearly 10% of the proband's plasma antithrombin in the latent form
and also, surprisingly, of small but definitive amounts of latent antithrombin in
normal plasma. The latent transition will be predictably accelerated not only by
gross mutations, as with antithrombin Wobble, to give severe episodic thrombosis,
but also by milder mutations, as with antithrombin Wibble, to trigger thrombosis
in the presence of other predisposing factors, including the conformational
stress imposed by the raised body temperatures of fevers. Both antithrombin
variants had an exceptional (25-fold) increase in heparin affinity and this,
together with an increased inhibitory activity against factor Xa, provides
evidence of the direct linkage of A-sheet opening to the conformational basis of
heparin binding and activation.
PMID- 9763553
TI - Treatment of acquired von Willebrand syndrome in patients with monoclonal
gammopathy of uncertain significance: comparison of three different therapeutic
approaches.
AB - Patients with monoclonal gammopathies of uncertain significance (MGUS) may
develop an acquired bleeding disorder similar to congenital von Willebrand
disease, called acquired von Willebrand syndrome (AvWS). In these patients,
measures to improve hemostasis are required to prevent or treat bleeding
episodes. We diagnosed 10 patients with MGUS and AvWS: 8 had IgGkappa (3) or
lambda (5) MGUS and 2 IgM-kappa MGUS. Three therapeutic approaches were compared
in them: (1) desmopressin (DDAVP), (2) factor VIII/von Willebrand factor
(FVIII/vWF) concentrate, and (3) high-dose (1 g/kg/d for 2 days) intravenous Ig
(IVIg). In patients with IgG-MGUS, DDAVP and FVIII/vWF concentrate increased
factor VIII and von Willebrand factor in plasma, but only transiently. IVIg
determined a more sustained improvement of the laboratory abnormalities and
prevented bleeding during surgery (short-term therapy). In addition to the
standard 2-day infusion protocol, a long-term IVIg therapy was performed in 2
patients with IgG-MGUS: repeated (every 21 days) single infusions of IVIg did
improve laboratory abnormalities and stopped chronic gastrointestinal bleeding.
On the other hand, IVIg failed to correct laboratories abnormalities in patients
with IgM-MGUS. These comparative data obtained in a relative large and
homogeneous group of patients with AvWS and MGUS confirm that DDAVP and FVIII/vWF
concentrates improve the bleeding time (BT) and FVIII/vWF measurements only
transiently, whereas IVIg provides a sustained treatment of AvWS associated with
IgG-MGUS, but not with IgM-MGUS.
PMID- 9763555
TI - Successful treatment of invasive aspergillosis in chronic granulomatous disease
by bone marrow transplantation, granulocyte colony-stimulating factor-mobilized
granulocytes, and liposomal amphotericin-B.
AB - X-linked chronic granulomatous disease (X-CGD) is a primary immunodeficiency with
complete absence or malfunction of the nicotinamide adenine dinucleotide
phosphate (NADPH) oxidase in the phagocytic cells. Life-threatening infections
especially with aspergillus are common despite optimal antimicrobial therapy.
Bone marrow transplantation (BMT) is contraindicated during invasive
aspergillosis in any disease setting. We report an 8-year-old patient with CGD
who underwent HLA-genoidentical BMT during invasive multifocal aspergillus
nidulans infection, nonresponsive to treatment with amphotericin-B and gamma
interferon. During the first 10 days post-BMT, the patient received granulocyte
colony-stimulating factor (G-CSF)-mobilized, 25 Gy irradiated granulocytes from
healthy volunteers plus G-CSF beginning on day 3 to prolong the viability of the
transfused granulocytes. This was confirmed in vitro by apoptosis assays and in
vivo by finding nitroblue tetrazolium (NBT)-positive granulocytes in peripheral
blood 12 and 36 hours after the transfusions. Clinical and biological signs of
infection began to disappear on day 7 post-BMT. Positron emission tomography with
F18-fluorodeoxyglucose (FDG-PET) and computed tomography (CT) scans at 3 months
post-BMT showed complete disappearance of infectious foci. At 2 years post-BMT,
the patient is well with full immune reconstitution and no sign of aspergillus
infection. Our results show that HLA-identical BMT may be successful during
invasive, noncontrollable aspergillus infection, provided that supportive therapy
is optimal.
PMID- 9763554
TI - Incidence, clinical features, and outcome of all trans-retinoic acid syndrome in
413 cases of newly diagnosed acute promyelocytic leukemia. The European APL
Group.
AB - All trans-retinoic acid (ATRA) syndrome is a life-threatening complication of
uncertain pathogenesis that can occur during the treatment of acute promyelocytic
leukemia (APL) by ATRA. Since its initial description, however, no large series
of ATRA syndrome has been reported in detail. We analyzed cases of ATRA syndrome
observed in an ongoing European trial of treatment of newly diagnosed APL. In
this trial, patients 65 years of age or less with an initial white blood cell
count (WBC) less than 5,000/microL were initially randomized between ATRA
followed by chemotherapy (CT) (ATRA-->CT group) or ATRA with CT started on day 3;
patients with WBC greater than 5,000/microL received ATRA and CT from day 1;
patients aged 66 to 75 received ATRA-->CT. In patients with initial WBC less than
5, 000/microL and allocated to ATRA-->CT, CT was rapidly added if WBC was greater
than 6,000, 10,000, 15,000/microL by days 5, 10, and 15 of ATRA treatment. A
total of 64 (15%) of the 413 patients included in this trial experienced ATRA
syndrome during induction treatment. Clinical signs developed after a median of 7
days (range, 0 to 35 days). In two of them, they were in fact present before the
onset of ATRA. In 11 patients, they occurred upon recovery from the phase of
aplasia due to the addition of CT. Respiratory distress (89% of the patients),
fever (81%), pulmonary infiltrates (81%), weight gain (50%), pleural effusion
(47%), renal failure (39%), pericardial effusion (19%), cardiac failure (17%),
and hypotension (12%) were the main clinical signs, and 63 of the 64 patients had
at least three of them. Thirteen patients required mechanical ventilation and two
dialysis. A total of 60 patients received CT in addition to ATRA as per protocol
or based on increasing WBC; 58 also received high dose dexamethasone (DXM); ATRA
was stopped when clinical signs developed in 30 patients. A total of 55 patients
(86%) who experienced ATRA syndrome achieved complete remission (CR), as compared
with 94% of patients who had no ATRA syndrome (P = .07) and nine (14%) died of
ATRA syndrome (5 cases), sepsis (2 cases), leukemic resistance (1 patient), and
central nervous system (CNS) bleeding (1 patient). None of the patients who
achieved CR and received ATRA for maintenance had ATRA syndrome recurrence. No
significant predictive factors of ATRA syndrome, including pretreatment WBC,
could be found. Kaplan Meier estimates of relapse, event-free survival (EFS), and
survival at 2 years were 32% +/- 10%, 63% +/- 8%, and 68% +/- 7% in patients who
had ATRA syndrome as compared with 15% +/- 3%, 77% +/- 2%, and 80% +/- 2% in
patients who had no ATRA syndrome (P = .05, P = .003, and P = .03), respectively.
In a stepwise Cox model that also included pretreatment prognostic variables,
ATRA syndrome remained predictive for EFS and survival. In conclusion, in this
multicenter trial where CT was rapidly added to ATRA in case of high or
increasing WBC counts and DXM generally also used at the earliest clinical sign,
the incidence of ATRA syndrome was 15%, but ATRA syndrome was responsible for
death in only 1.2% of the total number of patients treated. However, occurrence
of ATRA syndrome was associated with lower EFS and survival.
PMID- 9763556
TI - Efficacy and costs of granulocyte colony-stimulating factor in allogeneic T-cell
depleted bone marrow transplantation.
AB - Hematopoietic growth factors have shown clinical benefits in patients undergoing
chemotherapy and stem cell transplantation, but few studies have been performed
to assess whether the benefits are worth the costs. We reviewed 196 patients
undergoing T-cell depleted related donor bone marrow transplantation (BMT)
between 1990 and 1996 to assess the effect of growth factor use on time to
engraftment and costs of hospitalization. Beginning in 1994, based on encouraging
results in autologous transplantation, patients (n = 81) were treated with
granulocyte colony-stimulating factor (G-CSF) starting at day +1 after marrow
infusion until engraftment. Between January 1, 1990 and January 1, 1994, patients
(n = 115) did not receive growth factor. CD6 depletion of donor marrow was the
only form of prophylaxis against graft-versus-host disease (GVHD). Despite
receiving a lower stem cell dose (P = .004), the group receiving G-CSF had a
decreased time to engraftment (20 days v 12 days, P < .0001) and time from marrow
infusion to discharge (23 days v 17 days, P < .0001). In multivariate modeling,
the use of G-CSF was the most significant factor predicting time to engraftment
and discharge. Incidence of grades II-IV GVHD, early mortality, percentage of
patients who engrafted, and relapse rates did not differ between the groups.
Inpatient charges during the first 50 days after marrow infusion (including
readmissions) were available on 110 patients and were converted to costs using
departmental ratios of costs of charges. Median costs were significantly lower in
the group receiving G-CSF ($80,600 v $84,000, P = .0373). Thus, use of G-CSF in
this setting allows earlier hospital discharge with lower costs.
PMID- 9763557
TI - Philadelphia chromosome-positive (Ph+) childhood acute lymphoblastic leukemia:
good initial steroid response allows early prediction of a favorable treatment
outcome.
AB - Among 4,760 acute lymphoblastic leukemia (ALL) patients enrolled from 1986 to
1995 in two subsequent trials of the BFM and AIEOP study group, 61 patients were
found to have Philadelphia chromosome-positive (Ph+) ALL. These patients were
analyzed for presenting features and treatment outcome to identify specific
prognostic factors. Treatment stratification was based on initial cell mass and
early response as determined by blast count in peripheral blood after a 7-day
induction prephase with prednisone and one dose of intrathecal methotrexate on
day 1. All patients were treated by similar intensive Berlin-Frankfurt-Munster
(BFM) protocols. The median age of Ph+ patients was 7.5 years, the median white
blood cell count (WBC) was 75 x 10(9)/L, 77% of patients had common ALL, and 29%
coexpressed myeloid markers. After a median observation time of 4.2 years, 29 of
61 patients are alive (survival probability [pSUR] at 4 years, 0.49; standard
error [SE], 0.06), and 24 of 61 are in first complete remission (CR1; probability
of event-free survival [pEFS] at 4 years, 0.38; SE, 0.06). Twenty (35%) of 57
evaluable patients had >/=1,000 leukemic blasts per microliter of blood on day 8
of induction (defined as prednisone-poor-response [PPR]). These patients were
older (10.0 v 6.88 years; P = .02) and had a higher WBC (144 v 29 x 10(9)/L; P =
.0016) as compared with patients with prednisone good response (PGR; <1,000
blasts/microL at day 8). Only 2 of 20 patients (10%) with PPR remained in CR1 and
alive: 6 patients with PPR did not survive after allogeneic bone marrow
transplantation (BMT) due to recurring disease (n = 3) and toxicity (n = 3), and
12 nontransplanted patients died due to progression (n = 5) or relapse (n = 7).
In contrast, 26 (70%) of the 37 patients with PGR are alive. Of 18 patients
transplanted by allo-BMT, 1 relapsed (now in CR2) and 4 died after BMT. Among the
19 patients with PGR treated by chemotherapy alone, 8 remained in CR1 and 11
relapsed, of which 4 are in CR2 or CR3. The prednisone response emerged as the
only independent prognostic factor for survival in Cox regression analysis. Thus,
two thirds of Ph+ childhood ALL cases can be identified early by PGR, which, when
treated with intensive BFM chemotherapy, with or without BMT, have a
significantly lower risk of treatment failure. With a median continuous complete
remission (CCR) time of 4.1 years, pEFS for PGR is 0.55 (SE, 0.08) compared with
0.10 (SE, 0.07) in patients with PPR (P = .0001). PGR is also an indicator for
treatment responsiveness and durable second remission after relapse, which in
turn may provide a second chance for BMT.
PMID- 9763558
TI - Decreased rejection and improved survival of first and second marrow transplants
for severe aplastic anemia (a 26-year retrospective analysis).
AB - Between 1970 and 1996, 333 patients with severe aplastic anemia underwent HLA
matched related marrow transplant after conditioning with cyclophosphamide (CY).
Thirty-five percent of patients transplanted between 1970 and 1976 (group 1), 12%
of those transplanted between 1977 and 1981 (group 2), and 9% of patients
transplanted between 1982 and 1997 (group 3) had graft rejection. Graft rejection
occurred later among group 3 patients (median, 180 days) than among those in
groups 1 and 2 (medians, 28 and 47 days, respectively; P < .001 group 3 v 2). In
group 3, 92% of rejecting patients underwent a second transplant, compared with
78% and 77% in groups 1 and 2, respectively. Group 1 patients received various
conditioning regimens before second transplant, whereas most patients of groups 2
and 3 received CY combined with antithymocyte globulin (ATG). Graft-versus-host
disease (GVHD) prophylaxis after second transplant consisted of methotrexate
(MTX) for all group 1 and 2 patients, whereas group 3 patients received MTX
combined with cyclosporine (CSP). Over the three time periods studied, first
graft rejection decreased from 35% to 9%, and the proportion of rejecting
patients undergoing second transplants increased from 77% to 92%. The 10-year
probability of survival after second transplants increased from 5% to 83%.
Multivariate analysis showed MTX/CSP GVHD prophylaxis to be a significant factor
accounting for the increase in patient survival after second transplant.
PMID- 9763559
TI - A Gln747-->Pro substitution in the IIb subunit is responsible for a moderate
IIbbeta3 deficiency in Glanzmann thrombasthenia.
AB - To clarify a molecular defect responsible for moderate alphaIIb beta3 deficiency,
we examined two unrelated patients, MT and MS, suffering from type II and type I
Glanzmann thrombasthenia (GT), respectively. Sequence analysis of polymerase
chain reaction (PCR) fragments derived from platelet mRNA showed a single A-->C
substitution at nucleotide (nt) 2334 leading to a Gln747--> Pro in alphaIIb in
both patients. Allele-specific restriction enzyme analysis (ASRA) of genomic DNA
demonstrated that patient MT was homozygous for the Gln747-->Pro substitution and
patient MS was compound heterozygous for this substitution and for an RNA splice
mutation at the consensus sequence of the splice acceptor site of exon 18 (AG-
>AA). Furthermore, ASRA showed that, among 17 unrelated Japanese GT patients,
this Gln747-->Pro substitution was detected in 4 patients, including MT and MS
(homozygous, 2 patients; heterozygous, 2 patients). Cotransfection of
Pro747alphaIIb and beta3 constructs into 293 cells resulted in moderate reduction
in the amount of alphaIIb beta3 within the transfected cells as well as on the
cell surface. However, Pro747alphaIIb beta3 bound the ligand mimetic monoclonal
antibody (MoAb) PAC-1 after activation of alphaIIb beta3 by the MoAb PT25-2,
suggesting that the mutant alphaIIb beta3 possesses the ligand-binding function.
The association between the mutant proalphaIIb and beta3 was not disturbed.
Surface labeling and pulse chase study showed that the Gln747-->Pro substitution
moderately impaired both intracellular transport of the alphaIIb beta3
heterodimers to the Golgi apparatus and endoproteolytic cleavage of proalphaIIb
into heavy and light chains. By contrast, replacement of Gln747 with Ala by
mutagenesis did not impair alphaIIbbeta3 expression on the cell surface. These
results suggest that the presence of Pro, rather than the absence of Gln, at
amino acid residue 747 on alphaIIb is responsible for moderate alphaIIbbeta3
deficiency.
PMID- 9763560
TI - Lipopolysaccharide induces the antiapoptotic molecules, A1 and A20, in
microvascular endothelial cells.
AB - The effect of lipopolysaccharide (LPS) on endothelial cells is a key component of
the inflammatory response seen in Gram-negative sepsis. LPS does not cause death
of cultured human endothelial cells. However, when the expression of new proteins
is inhibited by cycloheximide, microvascular endothelial cells in culture undergo
apoptosis. This finding suggests that LPS induces apoptotic and antiapoptotic
pathways, with the antiapoptotic response being dependent on the synthesis of new
proteins. Concurrent activation of apoptotic and antiapoptotic pathways has
previously been documented for tumor necrosis factor (TNF). In the case of TNF,
the antiapoptotic signal has been attributed to at least two cytoprotective
proteins: the Bcl-2 homologue, A1, and the zinc-finger protein, A20. In this
study, we demonstrate that both these molecules are induced in microvascular
endothelial cells by LPS. Enforced overexpression of either A1 or A20 inhibits
LPS and cycloheximide-initiated apoptosis. Induction of A1 and A20 does not
require synthesis of intermediary proteins, but is dependent on the presence of
soluble CD14. In addition, we show that inhibition of signaling by the
transcription factor, NF-kappaB, blocks accumulation of A1 and A20 mRNA. Taken
together, our findings suggest that LPS directly induces expression of the
cytoprotective proteins, A1 and A20, via a CD14-dependent pathway requiring
activation of NF-kappaB.
PMID- 9763561
TI - The Val34Leu polymorphism in the A subunit of coagulation factor XIII contributes
to the large normal range in activity and demonstrates that the activation
peptide plays a role in catalytic activity.
AB - There is a wide normal range of coagulation factor XIII activity that has never
been adequately explained. A polymorphism substituting leucine for valine at
position 34 in the activation peptide of the A subunit of factor XIII has
recently been discovered in nondeficient individuals, and the present studies
indicate that the leucine substitution results in a significant increase in
transglutaminase activity. The frequency of the Leu34 allele in the Australian
Caucasian population is 0.27, which is high enough to suggest that the
inheritance of either the Val34 or Leu34 alleles may contribute to the wide
normal range of activity. Although there has been structural evidence indicating
that the activation peptide does not dissociate from the enzyme after thrombin
cleavage, the discovery of elevated activity resulting from the Leu34
substitution is the first direct evidence that the activation peptide plays a
continuing role in the function of factor XIII.
PMID- 9763562
TI - Polymorphisms of platelet membrane glycoprotein Ib associated with arterial
thrombotic disease.
AB - Platelet membrane glycoprotein Ibalpha (GPIbalpha) is a major receptor for von
Willebrand factor and thrombin, which plays a key role in the initial development
of thrombi. Two polymorphisms (HPA-2 and VNTR) that affect phenotype have been
described in GPIbalpha. The relevance of these polymorphisms to thrombotic
disease was investigated by genotypic identification in three case-control
studies: 104 case patients with acute cerebrovascular disease (CVD), 101 case
patients with acute coronary heart disease (CHD), 95 patients with deep venous
thrombosis (DVT), and one control age-, sex-, and race-matched for each case
patient. Results show that the C/B genotype of the VNTR and the HPA-2b
polymorphisms of GPIbalpha are strongly associated with increased risk of
coronary heart disease and cerebral vascular disease but not with deep vein
thrombosis. These two polymorphisms of GPIbalpha may represent newly identified
risk factors for arterial thrombotic disease, but not for venous thrombosis.
PMID- 9763563
TI - Human integrin beta3 gene expression: evidence for a megakaryocytic cell-specific
cis-acting element.
AB - The human integrin beta3 participates in a wide range of adhesive biologic
functions and is expressed in a selected subset of tissues, but little is known
about the cis-acting DNA elements or trans-acting factors responsible for this
regulation. Using cell lines characterized for beta3 expression, a number of
upstream regulatory regions in the beta3 gene were identified. (1) The three
regions from -1159 to -584, -290 to -146, and -126 to -115 demonstrated positive,
negative, and negative activity, respectively. (2) The region from -115 to +29 of
the beta3 gene was sufficient for cell-specific activity. Deletion of the
sequence from -115 to -89 produced a 6- to 40-fold reduction in reporter gene
activity in beta3-expressing megakaryocytic cell lines (K562, Dami, and HEL), but
only a 1.7- and 2.7-fold reduction, respectively, in beta3-expressing endothelial
and melanoma cell lines, and 1.3- and 2. 8-fold reduction, respectively, in non
beta3-expressing Chinese hamster ovary and 293 cell lines. This sequence also
bound nuclear proteins in a cell-specific manner in electrophoretic mobility
shift assays. Mutational analysis indicated that the sequence GAGGGG (positions
113 to -108) is a megakaryocytic cell line-specific cis-acting element. (3) The
region from -89 to +29 promoted lower activity in all cell lines. We also provide
evidence that a CCCACCC sequence at position -70 has transcriptional activity,
most likely through the Sp1 transcription factor. These data supply the first
detailed map of the transcriptional regulatory elements of the 5' region of the
beta3 gene, define positive regulatory sequences with potent megakaryocyte
preferential activity, and indicate that the ubiquitous transcription factor,
Sp1, may augment beta3 gene expression.
PMID- 9763564
TI - Tissue distribution and regulation of murine von Willebrand factor gene
expression in vivo.
AB - von Willebrand factor (vWF) is frequently used as a biochemical marker for
endothelial cells (ECs). Despite this, little is known about the relative level
of expression and regulation of this hemostatic factor in ECs in different
vascular beds in vivo. In the present study, we used quantitative reverse
transcription polymerase chain reaction and in situ hybridization analysis to
study vWF gene expression in murine tissues. Large differences in the level of
vWF mRNA were observed when comparing highly vascularized tissues, with the lung
and brain containing 5 to 50 times higher concentrations of vWF mRNA than the
kidney and liver. In this regard, ECs of small vessels and some microvessels in
the lung and brain expressed abundant vWF mRNA, whereas ECs of similar sized
vessels in the liver and kidney expressed relatively low levels. In general,
significantly higher levels of vWF mRNA and antigen were demonstrated in ECs of
larger vessels compared with microvessels and in venous ECs compared with
arterial ECs. Although intraperitoneal administration of endotoxin (or tumor
necrosis factor-alpha) increased plasma vWF levels, it had variable effects on
the steady-state level of vWF mRNA in murine tissues (ie, it decreased vWF mRNA
in many tissues, increased it in others, and had little effect on still others).
These results indicate that vWF is differentially expressed and regulated in ECs
present in different tissues and within the same vascular bed.
PMID- 9763565
TI - Ig heavy chain third complementarity determining regions (H CDR3s) after stem
cell transplantation do not resemble the developing human fetal H CDR3s in size
distribution and Ig gene utilization.
AB - Previous studies have suggested that the B-cell repertoire after stem cell
transplantation resembles the developing repertoire in the fetus. Fetal and adult
repertoires differ strikingly at the molecular level in Ig heavy chain third
complementarity determining region (H CDR3) size distribution and Ig gene
utilization. Previously, the posttransplant repertoire has not been studied fully
in this regard. In this study, we analyzed H CDR3s posttransplant using CDR3
fingerprinting, single-strand conformation polymorphism (SSCP), and random
sequencing. Eleven adult patients who received either autologous (n = 6) or
allogeneic adult sibling (n = 5) hematopoietic stem cell transplants were
studied. IgM H CDR3 repertoires demonstrated limited clonal diversity within the
first 6 to 10 weeks posttransplant. By 3 to 4 months, the IgM H CDR3 repertoires
were as diverse as those in healthy adults. Reconstitution of the IgM diversity
correlated with the expansion of the multimember VH3 family. By contrast, the
contribution of the single-member VH6 family was limited in most patients up to 6
to 9 months. No evidence was seen for greater contribution of VH6 posttransplant.
IgG repertoires remained clonally restricted at all times. In all patients, H
CDR3 sizes fell within adult limits. Direct nucleotide sequencing of H CDR3s
showed adult-type N-nucleotide insertions and Ig gene utilization. These results
indicate that the emerging repertoire posttransplant does not resemble the
developing fetal repertoire at the molecular level.
PMID- 9763566
TI - RP105 is associated with MD-1 and transmits an activation signal in human B
cells.
AB - RP105 was originally discovered as a mouse B-cell surface molecule that transmits
an activation signal. The signal leads to resistance against irradiation-induced
apoptosis and massive B-cell proliferation. Recently, we found that mouse RP105
is associated with another molecule, MD-1. We have isolated here the human MD-1
cDNA. We show that human MD-1 is also associated with human RP105 and has an
important role in cell surface expression of RP105. We also describe a monoclonal
antibody (MoAb) that recognizes human RP105. Expression of RP105 is restricted to
CD19(+) B cells. Histological studies showed that RP105 is expressed mainly on
mature B cells in mantle zones. Germinal center cells are either dull or
negative. RP105 is thus a novel human B-cell marker that is preferentially
expressed on mature B cells. Moreover, the anti-RP105 MoAb activates B cells,
leading to increases in cell size, expression of a costimulatory molecule CD80,
and DNA synthesis. The B-cell activation pathway using RP105 is conserved in
humans.
PMID- 9763567
TI - A regulatory role for Fcgamma receptors CD16 and CD32 in the development of
murine B cells.
AB - Early in development, murine B-lineage progenitor cells express two classes of
IgG Fc receptors (FcgammaR) designated as FcgammaRII (CD32) and FcgammaRIII
(CD16), but mature B lymphocytes only express FcgammaRII (CD32), which functions
as an inhibitor of B-cell activation when it is induced to associate with mIgM.
The functions of CD16 and CD32 on B-lineage precursor cells have not previously
been investigated. To search for FcgammaR functions on developing B-lineage
cells, normal murine bone marrow cells were cultured in the presence of 2.4G2, a
rat monoclonal antibody that binds to CD16 and CD32, or in the presence of
control normal rat IgG, and then the B-lineage compartment was analyzed for
effects. Cultures that contained 2.4G2 showed enhanced growth and differentiation
of B-lineage cells compared with control cultures. The enhancing effect of 2.4G2
also occurred when fluorescence-activated cell-sorted B-cell precursors (B220(+),
sIgM-, HSAhigh, FcgammaR+) from normal bone marrow were cocultured with BMS2, a
bone marrow stromal cell line, but not when they were cultured in BMS2
conditioned media. The enhancement of B-lineage development induced by 2.4G2 was
CD16-dependent and CD32-dependent, because 2.4G2 did not effect B-lineage growth
or differentiation in cultures of bone marrow from mice in which either the gene
encoding CD16 or CD32 had been disrupted. Analysis of fresh bone marrow from the
CD16 gene-disrupted mice showed normal numbers and distribution of cells within
the B-cell compartment, but in CD32 gene-disrupted mice, the B-cell compartment
was significantly enlarged. These experiments provide several lines of evidence
that the FcgammaR expressed on murine B-cell precursors can influence their
growth and differentiation.
PMID- 9763568
TI - Prolonged phenotypic, functional, and molecular change in group I Burkitt
lymphoma cells on short-term exposure to CD40 ligand.
AB - Group I Burkitt lymphoma (BL) cell lines (L3055, Elijah, Louckes, BL2, and BL29)
retaining the original biopsy phenotype were found to undergo prolonged
phenotypic, functional, and molecular change on short-term exposure to soluble
recombinant CD40L trimer. Sensitivity to, extent of, and duration of change
appeared to reflect passage number in that the earliest passaged lines, L3055 and
BL29, were generally the most susceptible. Culture of group I BL lines with CD40L
resulted in significant growth arrest (without apoptosis) that, for L3055 cells,
was sustained for 7 to 9 days after 72 hours of exposure. This was accompanied by
the formation of large homotypic aggregates together with gross changes in
individual cell morphology and a concomitant upregulation of CD54 (ICAM-1). Three
of the five group I BL lines exhibited rapid downregulation of the hallmark CD77
surface antigen, which, for L3055 cells, was maintained for at least 12 days
after 72 hours of incubation with CD40L. With the exception of BL2, all group I
BL lines were induced to express CD40 homodimers on CD40-stimulation, whereas
only monomers were detected in unstimulated cells. Experiments using CD40
transfected Rat-1 fibroblasts showed that the ability to signal for dimer
formation required Thr234 of CD40. For L3055 and BL29 cells, an initial 72 hours
of exposure to CD40L resulted in the maintenance of homodimers for up to 14 and
10 days, respectively. There was a close correlation between the induction and
duration of CD40 homodimers and the appearance of Bcl-2. For L3055 cells, which
are sensitive to apoptosis-induction on BCR-engagement, exposure to CD40L for 72
hours was found to provide considerable protection from anti-IgM, which was still
significant to 20 days. The implications of such sustained effects on relatively
short-term exposure of tumor B cells to CD40L are discussed.
PMID- 9763569
TI - A high frequency of circulating B cells share clonotypic Ig heavy-chain VDJ
rearrangements with autologous bone marrow plasma cells in multiple myeloma, as
measured by single-cell and in situ reverse transcriptase-polymerase chain
reaction.
AB - In multiple myeloma (MM), the VDJ rearrangement of the immunoglobulin heavy chain
expressed by MM plasma cells provides a unique clonotypic marker. Although
clonotypic MM cells have been found in the circulation, their number has been
controversial. Our objective was to provide direct evidence, using single-cell
assays, for the frequency of clonotypic cells in blood of 18 MM patients, and to
confirm their identity as B cells. The clonotypic Ig heavy-chain (IgH) VDJ was
determined from single plasma cells using consensus reverse transcriptase
polymerase chain reaction (RT-PCR), subcloning, and sequencing. For all patients,
using patient-specific primers, clonotypic transcripts were amplified from 10 or
more individual plasma cells. Using in situ RT-PCR, for all patients greater than
80% of plasma cells were found to be clonotypic. Three separate methods, RT-PCR,
single-cell RT-PCR, and in situ RT-PCR, were used to analyze clonotypic cells in
peripheral blood mononuclear cells (PBMC) from MM patients. Sequencing of the IgH
transcripts expressed by individual cells obtained by limiting dilution of
freshly isolated PBMC from a MM patient showed that all B cells expressed an
identical CDR3. This intraclonal homogeneity indicates an escape from antigenic
selection, characteristic of malignant B cells. For this patient, the frequency
of clonotypic PBMC, about 25%, was comparable to the number of PBMC B cells
(34%). Because the PBMC included less than 1% plasma cells, virtually all
clonotypic PBMC must be B cells. Using single-cell RT-PCR, clonotypic IgH
transcripts were identified in individual sorted B cells from blood. To
accurately quantify the number of clonotypic B cells, sorted B cells derived from
18 MM patients (36 samples) and 18 healthy donors (53 samples) were analyzed
using in situ RT-PCR with patient-specific primers. Clonotypic transcripts were
not detectable among normal B cells. For the 18 MM patients, a mean of 66% +/- 4%
(SE) of blood B cells were clonotypic (range, 9% to 95%), with mean absolute
number of 0.15 +/- .02 x 10(9)/L blood. Over time in individual patients,
conventional chemotherapy transiently decreased circulating clonotypic B cells.
Their numbers were increased in granulocyte colony-stimulating factor (G-CSF)-
mobilized blood of one patient. However, clonotypic B cells of a one patient
became undetectable after allogeneic transplant, correlating with complete
remission. Although contributions to MM spread and progression is likely, their
malignant status and impact has yet to be clarified. Their high frequency in the
blood, and their resistence to conventional chemotherapy suggests that the number
of circulating clonotypic cells should be clinically monitored, and that
therapeutic targeting of these B cells may benefit myeloma patients.
PMID- 9763570
TI - The relationship between thiopurine methyltransferase activity and genotype in
blasts from patients with acute leukemia.
AB - The level of expression of the enzyme thiopurine methyltransferase (TPMT) is an
important determinant of the metabolism of thiopurines used in the treatment of
acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Studies in
red blood cells (RBC) have shown that TPMT expression displays genetic
polymorphism with 11% of individuals having intermediate and one in 300
undetectable levels. The genetic basis for this polymorphism has now been
elucidated and polymerase chain reaction (PCR)-based assays described for the
most common mutations accounting for reduced activity. In previous studies,
genotype has been correlated with red blood cell activity. In this report, we
describe the relationship between genotype and TPMT activity measured directly in
the target of drug action, the leukemic cell. We have demonstrated that the TPMT
activity in lymphoblasts from 38 children and adults found by PCR to be
homozygotes (*1/*1) was significantly higher than that in the five heterozygotes
(*1/*3) detected (median, 0.25 v 0.08, P < .002, Mann-Whitney U). Similar results
were obtained when results from children were analyzed separately. However,
comparison of activity in blasts from AML and ALL showed a higher level in the
former (0.35 v 0.22 nU/mg, P < .002, n = 17, 35), suggesting that factors other
than genotype may also influence expression.
PMID- 9763571
TI - Altered expression and activity of topoisomerases during all-trans retinoic acid
induced differentiation of HL-60 cells.
AB - Regulation of topoisomerase II (TOPO II) isozymes alpha and beta is influenced by
the growth and transformation state of cells. Using HL-60 cells induced to
differentiate by all-trans retinoic acid (RA), we have investigated the
expression and regulation of TOPO II isozymes as well as the levels of
topoisomerase I (TOPO I). During RA-induced differentiation of human leukemia HL
60 cells, levels of TOPO I remained unchanged, whereas the levels and
phosphorylation of TOPO IIalpha and TOPO IIbeta proteins were increased twofold
to fourfold and fourfold to eightfold, respectively. The elevation of TOPO II
(alpha and beta) protein levels and phosphorylation was apparent at 48 hours of
treatment with RA and persisted through 96 hours. The increased level of TOPO
IIbeta protein was also detected in differentiated cells subsequently cultured
for 96 hours in RA-free medium. Pulse chase experiments in cells labeled with 35S
methionine showed that the rate of degradation of TOPO IIbeta protein in control
cells was about twofold faster than that in the differentiated RA-treated cells.
The level of decatenation activity of kDNA was comparable in nuclear extracts
from control or RA-treated cells. Whereas etoposide (1 to 10 micromol/L) -induced
DNA cleavage was not significantly different, apoptosis was significantly lower
(P = .012) in RA-treated versus control cells after exposure to 10 micromol/L
etoposide. Consistent with unaltered levels of TOPO I, camptothecin (CPT)
induced DNA cleavage was similar in control or RA-treated cells. However,
apoptosis after exposure to 1 to 10 micromol/L CPT was significantly lower (P =
.003 to P < .001) in RA-treated versus control cells. Results suggest that TOPO
IIbeta protein levels are posttranscriptionally regulated and that degradation of
TOPO IIbeta is decreased during RA-induced differentiation. Furthermore, whereas
the total level of TOPO II (alpha + beta) is increased with RA, the level of TOPO
II catalytic activity and etoposide-stabilized DNA cleavage activity remains
unaltered. Thus, TOPO IIbeta may have a specific role in transcription of genes
involved in differentiation with RA treatment.
PMID- 9763572
TI - DNA fiber fluorescence in situ hybridization analysis of immunoglobulin class
switching in B-cell neoplasia: aberrant CH gene rearrangements in follicle center
cell lymphoma.
AB - Immunoglobulin class switching usually involves deletion of part of the
immunoglobulin CH region. By DNA fiber fluorescence in situ hybridization (FISH)
with a barcode of probes covering the DH, JH, and CH genes, the configuration of
the entire CH region can be visualized on single DNA molecules. Using this
technique, we have studied class switching in three types of B-cell neoplasia,
mantle-cell lymphoma (MCL), follicular lymphoma (FL) and hairy cell leukemia
(HCL), representing B cells in, respectively, pregerminal center, germinal
center, and postgerminal center stages of development. In MCL and FL,
simultaneous detection of the t(11;14) and t(14;18) breakpoint with probes for
the BCL-1 and BCL-2 loci, respectively, allowed differentiation between
productive and nonproductive alleles. In none of 10 MCL cases was class switching
detected. In 21 HCL, all nonimmunoglobulin M (IgM) cases had class-switch
deletion consistent with the expressed isotype on at least one allele. In FL,
however, a peculiar pattern of CH rearrangement was observed. In IgM expressing
FL, the translocated alleles had switched in 11 of 13 cases, and the
nontranslocated allele showed complex rearrangements downstream from the Cmu
Cdelta genes in 9 of 13 cases. These downstream rearrangements may reflect tumor
specific deregulation of the class-switch machinery. All seven immunoglobulin G
(IgG) expressing FL showed class switching on both alleles. Fiber FISH analysis
also showed several polymorphisms. The most frequent one, present on 38% of all
analyzed alleles, consisted of an extra Cgamma gene or pseudogene in the 3'
cluster.
PMID- 9763573
TI - CBFA2(AML1) translocations with novel partner chromosomes in myeloid leukemias:
association with prior therapy.
AB - CBFA2(AML1) has emerged as a gene critical in hematopoiesis; its protein product
forms the DNA-binding subunit of the heterodimeric core-binding factor (CBF) that
binds to the transcriptional regulatory regions of genes, some of which are
active specifically in hematopoiesis. CBFA2 forms a fusion gene with ETO and
MDS1/EVI1 in translocations in myeloid leukemia and with ETV6(TEL) in the
t(12;21) common in childhood pre-B acute lymphoblastic leukemia. We have analyzed
samples from 30 leukemia patients who had chromosome rearrangements involving
21q22 by using fluorescence in situ hybridization (FISH). Our analysis showed
that 7 of them involved CBFA2 and new translocation partners. Two patients had a
t(17;21)(q11.2;q22), whereas the other 5 had translocations involving 1p36, 5q13,
12q24, 14q22, or 15q22. Five of these novel breakpoints in CBFA2 occurred in
intron 6; this same intron is involved in the t(3;21). One breakpoint mapped to
the t(8;21) breakpoint region in intron 5, and 1 mapped 5' to that region. All 7
CBFA2 rearrangements resulted from balanced translocations. All 7 patients had
myeloid disorders (acute myeloid leukemia or myelodysplastic syndrome); 2 were de
novo and 5 had treatment histories that included topoisomerase II targeting
agents. The association of therapy-related disorders with translocations
involving CBFA2 was significant by Fisher's exact test (P < .003). These results
provide further evidence that this region of CBFA2 is susceptible to breakage in
cells exposed to topoisomerase II inhibitors.
PMID- 9763574
TI - Fluorescence in situ hybridization of progenitor cells obtained by fluorescence
activated cell sorting for the detection of cells affected by chromosome
abnormality trisomy 8 in patients with myelodysplastic syndromes.
AB - Myelodysplastic syndrome (MDS) is believed to be a stem-cell disorder involving
cytopenia and dysplastic changes in three hematopoietic lineages. However, the
involvement of pluripotent stem cells and progenitor cells has not been clarified
conclusively. To address this issue, we used fluorescence in situ hybridization
(FISH) of blood and bone marrow (BM) smears for mature cells and FISH of cells
sorted by fluorescence-activated cell sorting for progenitor cells. Seven
patients with MDS associated with trisomy 8 were studied. FISH showed +8 in
granulocytes, monocytes, and erythroblasts, but not in lymphocytes. Sorted cells
of T (CD3(+)), B (CD19(+)), and NK cells (CD3(-)CD56(+)) from peripheral blood
did not contain +8, nor did CD34(+) subpopulations from BM including B
(CD34(+)CD19(+)), T/NK (CD34(+)CD7(+)) progenitors, and pluripotent stem cells
(CD34(+)Thy1(+)). The +8 chromosome abnormality was identified in stem cells only
at the level of colony-forming unit of granulocyte-erythrocyte-macrophage
megakaryocyte (CFU-GEMM; CD34(+)CD33(+)). It may thus be concluded that cells
affected by trisomy 8 in the context of MDS are at the CFU-GEMM level and that
cells of lymphoid lineage are not involved. These results provide new insights
into the biology of MDS and suggest that intensive chemotherapy and autologous BM
transplantation may become important therapeutic strategies.
PMID- 9763575
TI - 8Cl-cAMP cytotoxicity in both steroid sensitive and insensitive multiple myeloma
cell lines is mediated by 8Cl-adenosine.
AB - We have examined the cytotoxic effects of cyclic adenosine-3', 5'-monophosphate
(cAMP) derivatives on multiple myeloma cells lines and determined that the 8
Chloro substituted derivative (8Cl-cAMP) is one of the most potent. We report
here that 8Cl-cAMP is cytotoxic to both steroid sensitive and insensitive myeloma
cells with a half maximal concentration of approximately 3 micromol/L. 8Cl-cAMP
toxicity in myeloma cells is dependent on phosphodiesterase activity in the serum
of cell culture medium. A metabolite of 8Cl-cAMP, 8-Chloro-adenosine (8Cl-AD),
kills myeloma cells as effectively as 8Cl-cAMP. Adenosine deaminase (ADA)
converts 8Cl-AD into 8Cl-inosine and abrogates the cytotoxic effects of 8Cl-cAMP,
8Cl-AMP, and 8Cl-AD, as does 5-(p-Nitrobenzyl)-6-Thio-Inosine (NBTI), an
inhibitor of nucleoside uptake. These data suggest that 8Cl-cAMP must be
converted to 8Cl-AD and that 8Cl-AD is the compound that enters the cell.
Contrary to glucocorticoid-mediated cell death in myeloma cells, the pathway of
8Cl-AD-mediated cell death appears to be independent of interleukin-6 (IL-6)
actions. Although the exact mode of action for this agent is currently unknown,
its ability to kill steroid sensitive and insensitive multiple myeloma cells in
an IL-6 independent fashion may offer exciting new therapeutic options.
PMID- 9763576
TI - Detection of clonal Hodgkin and Reed-Sternberg cells with identical somatically
mutated and rearranged VH genes in different biopsies in relapsed Hodgkin's
disease.
AB - Hodgkin's disease (HD) represents a malignant lymphoma in which the putative
malignant Hodgkin and Reed-Sternberg (H-RS) cells are rare and surrounded by
abundant reactive cells. Single-cell analyses showed that H-RS cells regularly
bear clonal Ig gene rearrangements. However, there is little information on the
clinical evolution of HD in a given patient. In this study, we used the single
cell polymerase chain reaction (PCR) to identify H-RS cells with clonal Ig gene
rearrangements in biopsy specimens of patients with relapsed HD. The obtained
clonal variable region heavy-chain (VH) gene rearrangements were used to
construct tumor-clone-specific oligonucleotides spanning the complementarity
determining region (CDR) III and somatically mutated areas in the rearranged VH
gene. A number of biopsies were obtained during a period of 3 years from two HD
patients. H-RS cells with identical VH rearrangements were detected in two
separate infiltrated lymph nodes from one patient with nodular sclerosis HD. In a
second patient with mixed cellularity HD subtype, clonal VH rearrangements with
identical sequences were detected in infiltrated spleen and two lymph node
biopsies. Despite the high sensitivity of the PCR method used (one clonal cell in
10(5) mononuclear cells), residual H-RS cells were not found in peripheral blood,
leukapheresis material, purified CD34(+) stem cells or bone marrow. The results
show that different specimens from relapsed patients suffering from classical HD
carry the same clonotypic IgH rearrangements with identical somatic mutations,
demonstrating the persistence and the dissemination of a clonal tumor cell
population. Thus, PCR assays with CDRIII-specific probes derived from clonal H-RS
cells are of clinical importance in monitoring the dissemination of HD and tumor
progression and could be useful for analysis of minimal residual disease after
autologous stem cell transplantation.
PMID- 9763577
TI - Primary myeloma cells growing in SCID-hu mice: a model for studying the biology
and treatment of myeloma and its manifestations.
AB - Progress in unraveling the biology of myeloma has suffered from lack of an in
vitro or in vivo system for reproducible growth of myeloma cells and development
of disease manifestations. The SCID-hu mouse harbors a human microenvironment in
the form of human fetal bone. Myeloma cells from the bone marrow of 80% of
patients readily grew in the human environment of SCID-hu mice. Engraftment of
myeloma cells was followed by detectable human Ig levels in the murine blood.
Myeloma-bearing mice had high levels of monotypic human Igs, high blood calcium
levels, increased osteoclast activity, and severe resorption of the human bones.
The human microenvironment was infiltrated with Epstein-Barr virus-negative
monoclonal myeloma cells of the same clonality as the original myeloma cells.
Active angiogenesis was apparent in areas of myeloma cell infiltration; the new
endothelial cells were of human origin. We conclude that the SCID-hu mouse is a
favorable host for studying the biology and therapy of myeloma and that a normal
bone marrow environment can support the growth of myeloma cells.
PMID- 9763578
TI - Fas/APO-1 (CD95)-mediated apoptosis is activated by interferon-gamma and
interferon- in interleukin-6 (IL-6)-dependent and IL-6-independent multiple
myeloma cell lines.
AB - A poor response to Fas-induced apoptosis is evident in some multiple myeloma (MM)
cell lines and primary cells. In this study, we have examined the possibility to
increase the sensitivity to Fas-induced apoptosis by pretreatment of MM cells
with interferon-gamma (IFN-gamma) or interferon-alpha (IFN-alpha). Both IFN-gamma
and IFN-alpha markedly increased the Fas-induced apoptosis in all cell lines
tested (U-266-1970, U-266-1984, and U-1958). In the U-266-1970 and U-1958 cell
lines, pretreatment with either IFN-gamma or IFN-alpha also inhibited
proliferation in a dose-dependent manner. In contrast, IFN-gamma activation of
the Fas death pathway in the U-266-1984 cells was not accompanied by growth
inhibition. Incubation with the IFNs increased the Fas antigen expression in one
of three cell lines but did not alter the expression of Bcl-2 or Bax. The IFNs
are important regulators of growth and survival in MM cells. Our results suggest
that activation of Fas-mediated apoptosis is a novel mechanism by which the IFNs
exert inhibitory effects on MM cells.
PMID- 9763579
TI - Alterations in protein-DNA interactions in the gamma-globin gene promoter in
response to butyrate therapy.
AB - The mechanisms by which pharmacologic agents stimulate gamma-globin gene
expression in beta-globin disorders has not been fully established at the
molecular level. In studies described here, nucleated erythroblasts were isolated
from patients with beta-globin disorders before and with butyrate therapy, and
globin biosynthesis, mRNA, and protein-DNA interactions were examined. Expression
of gamma-globin mRNA increased twofold to sixfold above baseline with butyrate
therapy in 7 of 8 patients studied. A 15% to 50% increase in gamma-globin protein
synthetic levels above baseline gamma globin ratios and a relative decrease in
beta-globin biosynthesis were observed in responsive patients. Extensive new in
vivo footprints were detected in erythroblasts of responsive patients in four
regions of the gamma-globin gene promoter, designated butyrate-response elements
gamma 1-4 (BRE-G1-4). Electrophoretic mobility shift assays using BRE-G1
sequences as a probe demonstrated that new binding of two erythroid-specific
proteins and one ubiquitous protein, alphaCP2, occurred with treatment in the
responsive patients and did not occur in the nonresponder. The BRE-G1 sequence
conferred butyrate inducibility in reporter gene assays. These in vivo protein
DNA interactions in human erythroblasts in which gamma-globin gene expression is
being altered strongly suggest that nuclear protein binding, including alphaCP2,
to the BRE-G1 region of the gamma-globin gene promoter mediates butyrate activity
on gamma-globin gene expression.
PMID- 9763580
TI - Serum transferrin receptor and transferrin receptor-ferritin index identify
healthy subjects with subclinical iron deficits.
AB - Despite the established utility of serum transferrin receptor (sTfR), serum
ferritin, and the sTfR/log ferritin ratio (TfR-F Index) in the diagnosis of iron
deficiency (ID) anemia, the numeric values of these parameters, which are
indicative of subclinical ID, remain to be clearly defined. In this study, 65
apparently healthy nonanemic adults (22 men and 43 women) were treated with 3
months of oral iron supplementation to evaluate its effect on parameters
reflecting iron status and to determine the prevalence of subclinical iron
deficiency in apparently healthy adults. Significant supplementation-induced
changes were observed in sTfR, ferritin, and TfR-F Index values in women, whereas
in men, none of the studied parameters showed any significant change. Iron
deficient erythropoiesis (IDE) was not observed in men, but was found in 17 women
(40%). Although individuals with a compromised iron status may be represented in
substantial numbers in conventional reference populations, they can be readily
identified using sTfR, ferritin, and TfR-F Index determinations.
PMID- 9763582
TI - Sickle cell adhesion to laminin: potential role for the alpha5 chain.
AB - Sickle red blood cell (RBC) adhesion to the endothelium and to exposed,
underlying subendothelial proteins is believed to contribute to vascular
occlusion in sickle cell disease. Laminin, a major component of the
subendothelium, supports significant adhesion of sickle, but not normal RBCs. The
purpose of this study was to define the adhesive region for sickle RBCs within a
human laminin preparation using a flow adhesion assay designed to mimic
physiologic flow through postcapillary venules. Because sickle RBCs did not
adhere to the common laminin contaminants entactin or collagen type IV, neither
of these proteins are likely to contribute to the observed adhesion to laminin.
Known adhesive regions of laminin neither supported nor inhibited sickle RBC
adhesion to laminin, suggesting a mechanism of adhesion previously
uncharacterized in other laminin adhesion studies. Moreover, sickle RBCs did not
adhere to mouse EHS laminin or to human laminin-2 (merosin), eliminating the
alpha1, alpha2, beta1, and gamma1 chains as mediators of sickle cell adhesion.
The monoclonal antibody 4C7, which binds at or near the G-domain of the laminin
alpha5 chain, significantly inhibited sickle RBC adhesion. These results suggest
that an adhesive region for sickle RBCs is contained within the laminin alpha5
chain.
PMID- 9763581
TI - Molecular identification and functional characterization of a novel protein that
mediates the attachment of erythroblasts to macrophages.
AB - We have previously identified a novel protein that mediates the attachment of
erythroblasts to macrophages in vitro. This attachment promotes terminal
maturation and enucleation of erythroblasts (Hanspal and Hanspal, Blood 84:3494,
1994). This protein is referred to here as Emp for erythroblast macrophage
protein. Two immunologically related isoforms of Emp with apparent molecular
weights of 33 kD and 36 kD were detected in macrophage membranes. The complete
amino acid sequence of the larger isoform of Emp was deduced from the nucleotide
sequence of a full-length 2.0-kb cDNA that was isolated from a human macrophage
cDNA library using affinity-purified anti-Emp antibodies. Of the 2,005 bp, 1,185
bp encode for 395 amino acids representing 43 kD (the sodium dodecyl sulfate
polyacrylamide gel electrophoresis [SDS-PAGE] molecular mass is 36 kD). Northern
blot analysis of human macrophage poly(A) RNA detected a message for Emp of 2.1
kb. The deduced amino acid sequence contains a putative transmembrane domain near
the N-terminus. To investigate the structure/function relationships of Emp,
recombinant fusion proteins of full-length and truncated Emp were produced in
bacteria, COS-7, and HeLa cells. Cell binding assays showed that the N-terminus
is exposed on the cell surface. The recombinant Emp functions as a cell
attachment molecule when expressed in heterologous cells. Furthermore, we showed
that the demise of erythroblasts in the absence of Emp-mediated erythroblast
macrophage association is accompanied by apoptosis. We postulate that Emp
mediated contact between erythroblasts and macrophages promotes terminal
maturation of erythroid cells by suppressing apoptosis.
PMID- 9763584
TI - Role of CD28 in acute graft-versus-host disease.
AB - Because CD28-mediated T-cell costimulation has a pivotal role in the initiation
and maintenance of T-cell responses, we tested the hypothesis that CD28 is
critical for the development of graft-versus-host disease (GVHD). We compared the
in vivo effects of CD28(-/-) T cells transplanted from B6 donor with the CD28
gene deleted by homologous recombination with those of CD28(+/+) T cells
transplanted from wild-type C57BL/6 (B6) donor. Fifty million CD28(-/-) or
CD28(+/+) splenocytes from B6 mice were transplanted into unirradiated (B6 x
DBA/2)F1 (BDF1) recipients. Unlike CD28(+/+), CD28(-/-) T cells from B6 mice had
lower levels of proliferation and interleukin-2 production, had a limited ability
to generate cytotoxic T lymphocytes against the recipient, and did not induce
immune deficiency, despite survival in the recipient for at least 28 days. The
ability to prevent rejection was reduced by the absence of CD28, because as many
as 1.0 x 10(7) CD28(-/-) CD8(+) cells were needed to prevent rejection of major
histocompatibility complex (MHC) class-I incompatible marrow in sublethally
irradiated (550 cGy) bm1 recipients, whereas 8.0 x 10(5) CD28(+/+) CD8(+) T cells
were sufficient to produce a similar effect, indicating that CD28 on donor CD8(+)
cells helps to eliminate host immunity. Two million CD4(+) CD28(-/-) or CD28(+/+)
T cells were transplanted into sublethally irradiated (750 cGy), MHC class-II
incompatible (B6 x bm12)F1 recipients. With CD28(-/-) cells, 44% of the
recipients died at a median of 20 days compared with 94% at a median of 15 days
with CD28(+/+) cells (P < .001). Two million CD8(+) CD28(-/-) or CD28(+/+) T
cells were transplanted into sublethally irradiated (750 cGy), MHC class-I
incompatible (B6 x bm1) F1 recipients. With CD28(-/-) cells, 25% of the
recipients died at a median of 41 days compared with 100% at a median of 15 days
with CD28(+/+) cells (P < . 001). (B6 x bm12)F1 and (B6 x bm1)F1 mice surviving
after transplantation of CD28(-/-) cells recovered thymocytes, T cells, and B
cells in numbers and function comparable with that of irradiation-control F1
mice. We conclude that CD28 contributes to the pathogenesis and the severity of
GVHD. Our results suggest that the severity of GVHD could be decreased by the
administration of agents that block CD28 function in T lymphocytes.
PMID- 9763583
TI - The relationship of the -5, -8, and -24 variant alleles in African Americans to
triosephosphate isomerase (TPI) enzyme activity and to TPI deficiency.
AB - In 424 African-American and 75 white subjects, we found that the -5 (TPI 592 A-
>G), -8 (TPI 589 G-->A), and -24 (TPI 573 T-->G) variants in the triosephosphate
isomerase (TPI) gene occurred frequently (41.0%) in the African-American subjects
but did not occur in the whites. These data suggest that this set of
polymorphisms may turn out to be one of the higher-incidence molecular markers of
African lineage, a surprising finding because others had reported that these
nucleotide substitutions were restricted to a small subset of African Americans
who had been characterized as TPI-deficiency heterozygotes. Additionally, we
investigated the relationship of these variants to TPI-enzyme activity. Although
the variant substitutions (occurring in three haplotypes: -5 alone, -5 -8, and -5
-8 -24) were associated with moderate reduction in enzyme activity, severe
deficiency heterozygotes could not be identified with certainty, and none of the
haplotypes were restricted to subjects with marked reduction of enzyme activity.
Three subjects were homozygous for the -5 -8 haplotype, a finding inconsistent
with the putative role of this haplotype as the cause of a null variant
incompatible with life in homozygotes. Despite these findings, the possibility
remains that the -5 -8 or -5 -8 -24 haplotypes may in some instances contribute
to compound heterozygosity and clinical TPI deficiency.
PMID- 9763585
TI - Catecholaminergic regulation of hematopoiesis in mice.
PMID- 9763586
TI - Neural regulation of bone marrow.
PMID- 9763587
TI - High risk of chronic graft-versus-host disease in unmanipulated allogeneic
peripheral blood stem cell transplantation.
PMID- 9763588
TI - Mechanical properties of stored red blood cells using optical tweezers.
PMID- 9763590
TI - Juvenile genetic hemochromatosis is clinically and genetically distinct from the
classical HLA-related disorder.
PMID- 9763589
TI - A functional wild-type p53 gene is expressed in human acute myeloid leukemia cell
lines.
PMID- 9763591
TI - Hypermethylation of p15(INK4B) gene in a patient with acute myelogenous leukemia
evolved from paroxysmal nocturnal hemoglobinuria.
PMID- 9763592
TI - Interferon and ribavirin combination therapy in patients with chronic hepatitis C
and mixed cryoglobulinemia.
PMID- 9763593
TI - Questions raised by the Benelux CML Study Group: results from the randomized
study with hydroxyurea alone versus hydroxyurea combined with low-dose interferon
alpha2b for chronic myeloid leukemia.
PMID- 9763594
TI - FGFR3 gene mutations associated with human skeletal disorders occur rarely in
multiple myeloma.
PMID- 9763595
TI - Interleukin-2 receptor subunit expression and function on human peripheral T
cells is not dependent on the anticoagulant.
PMID- 9763596
TI - Primary recurrent miscarriages: anti-beta2-glycoprotein I IgG antibodies induce
an acquired activated protein C resistance that can be detected by the modified
activated protein C resistance test.
PMID- 9763597
TI - Antisense RNA crossing mitochondrial membrane?
PMID- 9763598
TI - Magnetic resonance imaging in myelofibrosis.
PMID- 9763599
TI - Detection of nonrandom chromosomal changes in multiple myeloma by comparative
genomic hybridization.
PMID- 9763601
TI - Immunocytochemical colocalization of specific immunoglobulin A with sendai virus
protein in infected polarized epithelium.
AB - Immunoglobulin (Ig)A provides the initial immune barrier to viruses at mucosal
surfaces. Specific IgA interrupts viral replication in polarized epithelium
during receptor-mediated transport, probably by binding to newly synthesized
viral proteins. Here, we demonstrate by immunoelectron microscopy that specific
IgA monoclonal antibodies (mAbs) accumulate within Sendai virus-infected
polarized cell monolayers and colocalize with the hemagglutinin- neuraminidase
(HN) viral protein in a novel intracellular structure. Neither IgG specific for
HN nor irrelevant IgA mAbs colocalize with viral protein. Treatment of cultures
with viral-specific IgA but not with viral-specific IgG or irrelevant IgA
decreases viral titers. These observations provide definitive ultrastructural
evidence of a subcellular compartment in which specific IgA and viral envelope
proteins interact, further strengthening our hypothesis of intracellular
neutralization of virus by specific IgA antibodies. Our results have important
implications for intracellular protein trafficking, viral replication, and viral
vaccine development.
PMID- 9763600
TI - Adenosine diphosphate (ADP)-ribosylation of the guanosine triphosphatase (GTPase)
rho in resting peripheral blood human T lymphocytes results in pseudopodial
extension and the inhibition of T cell activation.
AB - Scrape loading Clostridium botulinum C3 exoenzyme into primary peripheral blood
human T lymphocytes (PB T cells) efficiently adenosine diphosphate (ADP)
ribosylates and thus inactivates the guanosine triphosphatase (GTPase) Rho. Basal
adhesion of PB T cells to the beta1 integrin substrate fibronectin (Fn) was not
inhibited by inactivation of Rho, nor was upregulation of adhesion using phorbol
myristate acetate (PMA; 10 ng/ml) or Mn++ (1 mM) affected. Whereas untreated PB T
cells adherent to Fn remain spherical, C3-treated PB T cells extend F-actin
containing pseudopodia. Inactivation of Rho delayed the kinetics of PMA-dependent
PB T cell homotypic aggregation, a process involving integrin alphaLbeta2.
Although C3 treatment of PB T cells did not prevent adhesion to the beta1
integrin substrate Fn, it did inhibit beta1 integrin/CD3-mediated costimulation
of proliferation. Analysis of intracellular cytokine production at the single
cell level demonstrated that ADP-ribosylation of Rho inhibited beta1 integrin/
CD3 and CD28/CD3 costimulation of IL-2 production within 6 h of activation.
Strikingly, IL-2 production induced by PMA and ionomycin was unaffected by C3
treatment. Thus, the GTPase Rho is a novel regulator of T lymphocyte
cytoarchitecture, and functional Rho is required for very early events regulating
costimulation of IL-2 production in PB T cells.
PMID- 9763602
TI - Receptor editing occurs frequently during normal B cell development.
AB - Allelic exclusion is established in development through a feedback mechanism in
which the assembled immunoglobulin (Ig) suppresses further V(D)J rearrangement.
But Ig expression sometimes fails to prevent further rearrangement. In
autoantibody transgenic mice, reactivity of immature B cells with autoantigen can
induce receptor editing, in which allelic exclusion is transiently prevented or
reversed through nested light chain gene rearrangement, often resulting in
altered B cell receptor specificity. To determine the extent of receptor editing
in a normal, non-Ig transgenic immune system, we took advantage of the fact that
lambda light chain genes usually rearrange after kappa genes. This allowed us to
analyze kappa loci in IgMlambda+ cells to determine how frequently in-frame kappa
genes fail to suppress lambda gene rearrangements. To do this, we analyzed
recombined VkappaJkappa genes inactivated by subsequent recombining sequence (RS)
rearrangement. RS rearrangements delete portions of the kappa locus by a V(D)J
recombinase-dependent mechanism, suggesting that they play a role in receptor
editing. We show that RS recombination is frequently induced by, and inactivates,
functionally rearranged kappa loci, as nearly half (47%) of the RS-inactivated
VkappaJkappa joins were in-frame. These findings suggest that receptor editing
occurs at a surprisingly high frequency in normal B cells.
PMID- 9763603
TI - Cytotoxic T lymphocyte antigen 4 is induced in the thymus upon in vivo activation
and its blockade prevents anti-CD3-mediated depletion of thymocytes.
AB - The development of a normal T cell repertoire in the thymus is dependent on the
interplay between signals mediating cell survival (positive selection) and cell
death (negative selection or death by neglect). Although the CD28 costimulatory
molecule has been implicated in this process, it has been difficult to establish
a role for the other major costimulatory molecule, cytotoxic T lymphocyte antigen
(CTLA)-4. Here we report that in vivo stimulation through the T cell receptor
(TCR)-CD3 complex induces expression of CTLA-4 in thymocytes and leads to the
association of CTLA-4 with the SH2 domain-containing phosphatase (SHP)-2 tyrosine
phosphatase. Moreover, intrathymic CTLA-4 blockade dramatically inhibits anti-CD3
mediated depletion of CD4+CD8+ double positive immature thymocytes. Similarly,
anti-CD3-mediated depletion of CD4+CD8+ double positive cells in fetal thymic
organ cultures could also be inhibited by anti-CTLA-4 antibodies. Thus, our data
provide evidence for a role of CTLA-4 in thymic selection and suggest a novel
mechanism contributing to the regulation of TCR-mediated selection of T cell
repertoires.
PMID- 9763604
TI - Regulation of anti-DNA B cells in recombination-activating gene-deficient mice.
AB - Anti-DNA antibodies are regulated in normal individuals but are found in high
concentration in the serum of systemic lupus erythematosus (SLE) patients and the
MRL lpr/lpr mouse model of SLE. We previously studied the regulation of anti
double-stranded (ds)DNA and anti-single-stranded (ss)DNA B cells in a
nonautoimmune background by generating mice carrying immunoglobulin transgenes
coding for anti-DNAs derived from MRL lpr/lpr. Anti-dsDNA B cells undergo
receptor editing, but anti-ssDNA B cells seem to be functionally silenced. Here
we have investigated how anti-DNA B cells are regulated in recombination-
activating gene (RAG)-2-/- mice. In this setting, anti-dsDNA B cells are
eliminated by apoptosis in the bone marrow and anti-ssDNA B cells are partially
activated.
PMID- 9763605
TI - Type I interferon induces inhibitory 16-kD CCAAT/ enhancer binding protein
(C/EBP)beta, repressing the HIV-1 long terminal repeat in macrophages: pulmonary
tuberculosis alters C/EBP expression, enhancing HIV-1 replication.
AB - We have previously observed that HIV-1 replication is suppressed in uninflamed
lung and increased during tuberculosis. In vitro THP-1 cell-derived macrophages
inhibited HIV-1 replication after infection with Mycobacterium tuberculosis.
Suppression of HIV-1 replication was associated with inhibition of the HIV-1 long
terminal repeat (LTR) and induction of ISGF-3, a type I interferon (IFN)-specific
transcription factor. Repression of the HIV-1 LTR required intact CCAAT/enhancer
binding protein (C/EBP) sites. THP-1 cell-derived macrophages infected with M.
tuberculosis, lipopolysaccharide, or IFN-beta induced the 16-kD inhibitory
C/EBPbeta isoform and coincidentally repressed HIV-1 LTR transcription. C/EBPbeta
was the predominant C/EBP family member produced in THP-1 macrophages during HIV
1 LTR repression. In vivo, alveolar macrophages from uninflamed lung strongly
expressed inhibitory 16-kD C/EBPbeta, but pulmonary tuberculosis abolished
inhibitory C/EBPbeta expression and induced a novel C/EBP DNA binding protein.
Therefore, in vitro, proinflammatory stimulation produces an IFN response
inhibiting viral replication by induction of a C/EBPbeta transcriptional
repressor. THP-1 cell-derived macrophages stimulated with type I IFN are similar
to alveolar macrophages in the uninflamed lung in vivo. In contrast, the cellular
immune response in active pulmonary tuberculosis disrupts this innate immunity,
switching C/EBP expression and allowing high level viral replication.
PMID- 9763606
TI - Integrin-mediated ras-extracellular regulated kinase (ERK) signaling regulates
interferon gamma production in human natural killer cells.
AB - Recent evidence indicates that integrin engagement results in the activation of
biochemical signaling events important for regulating different cell functions,
such as migration, adhesion, proliferation, differentiation, apoptosis, and
specific gene expression. Here, we report that beta1 integrin ligation on human
natural killer (NK) cells results in the activation of Ras/mitogen-activated
protein kinase pathways. Formation of Shc-growth factor receptor-bound protein 2
(Grb2) and Shc-proline-rich tyrosine kinase 2-Grb2 complexes are the receptor
proximal events accompanying the beta1 integrin-mediated Ras activation. In
addition, we demonstrate that ligation of beta1 integrins results in the
stimulation of interferon gamma (IFN-gamma) production, which is under the
control of extracellular signal-regulated kinase 2 activation. Overall, our data
indicate that beta1 integrins, by delivering signals capable of triggering IFN
gamma production, may function as NK-activating receptors.
PMID- 9763607
TI - Coordinate activation of activator protein 1 and inflammatory cytokines in
response to Neisseria gonorrhoeae epithelial cell contact involves stress
response kinases.
AB - Neisseria gonorrhoeae (Ngo), the etiologic agent of gonorrhea, induce a number of
proinflammatory cytokines by contact to epithelial cells. Cytokine genes and a
variety of other immune response genes are activated as a result of the
regulatory function of immediate early response transcription factors including
activator protein 1 (AP-1). Since it is established that phosphorylation of c
Jun, the central component of AP-1, by the stress-activated c-Jun NH2-terminal
kinase (JNK) increases the transcriptional activity of AP-1, we studied whether
Ngo could induce stress response pathways involving JNK. We found that virulent
Ngo strains induce phosphorylation and activation of JNK but not of p38 kinase.
Analysis of a nonpathogenic Ngo strain revealed only weak JNK activation. In
respect to the molecular components upstream of the JNK signaling cascade, we
show that a dominant negative mutant of MAP kinase kinase 4 (MKK4) represses
transcription of an AP-1-dependent reporter gene. Regarding upstream stress
response factors involved in Ngo-induced MKK4/JNK/AP-1 activation, we identified
p21-activated kinase (PAK) but not MAPK/ERK kinase kinase (MEKK1). Inhibition of
small GTPases including Rac1 and Cdc42 by Toxin B prevented JNK and AP-1
activation. Our results indicate that Ngo induce the activation of
proinflammatory cytokines via a cascade of cellular stress response kinases
involving PAK, which directs the signal from the Rho family of small GTPases to
JNK/AP-1 activation.
PMID- 9763608
TI - Involvement of guanosine triphosphatases and phospholipase C-gamma2 in
extracellular signal-regulated kinase, c-Jun NH2-terminal kinase, and p38 mitogen
activated protein kinase activation by the B cell antigen receptor.
AB - Mitogen-activated protein (MAP) kinase family members, including extracellular
signal-regulated kinase (ERK), c-Jun NH2-terminal kinase ( JNK), and p38 MAP
kinase, have been implicated in coupling the B cell antigen receptor (BCR) to
transcriptional responses. However, the mechanisms that lead to the activation of
these MAP kinase family members have been poorly elucidated. Here we demonstrate
that the BCR-induced ERK activation is reduced by loss of Grb2 or expression of a
dominant-negative form of Ras, RasN17, whereas this response is not affected by
loss of Shc. The inhibition of the ERK response was also observed in
phospholipase C (PLC)-gamma2-deficient DT40 B cells, and expression of RasN17 in
the PLC-gamma2-deficient cells completely abrogated the ERK activation. The PLC
gamma2 dependency of ERK activation was most likely due to protein kinase C (PKC)
activation rather than calcium mobilization, since loss of inositol 1,4,5
trisphosphate receptors did not affect ERK activation. Similar to cooperation of
Ras with PKC activation in ERK response, both PLC-gamma2-dependent signal and
GTPase are required for BCR-induced JNK and p38 responses. JNK response is
dependent on Rac1 and calcium mobilization, whereas p38 response requires Rac1
and PKC activation.
PMID- 9763609
TI - Different protein tyrosine kinases are required for B cell antigen receptor
mediated activation of extracellular signal-regulated kinase, c-Jun NH2-terminal
kinase 1, and p38 mitogen-activated protein kinase.
AB - B cell antigen receptor (BCR) cross-linking activates three distinct families of
nonreceptor protein tyrosine kinases (PTKs): src-family kinases, Syk, and Btk;
these PTKs are responsible for initiating downstream events. BCR cross-linking in
the chicken DT40 B cell line also activates three distinct mitogen-activated
protein kinases (MAPKs): extracellular signal-regulated kinase (ERK)2, c-jun NH2
terminal kinase (JNK)1, and p38 MAPK. To dissect the functional roles of these
PTKs in MAPK signaling, activation of MAPKs was examined in various PTK-deficient
DT40 cells. BCR-mediated activation of ERK2, although maintained in Lyn-deficient
cells, was abolished in Syk-deficient cells and partially inhibited in Btk
deficient cells, indicating that BCR-mediated ERK2 activation requires Syk and
that sustained ERK2 activation requires Btk. BCR-mediated JNK1 activation was
maintained in Lyn-deficient cells but abolished in both Syk- and Btk-deficient
cells, suggesting that JNK1 is activated via a Syk- and Btk-dependent pathway.
Consistent with this, BCR-mediated JNK1 activation was dependent on intracellular
calcium and phorbol myristate acetate-sensitive protein kinase Cs. In contrast,
BCR-mediated p38 MAPK activation was detected in all three PTK-deficient cells,
suggesting that no single PTK is essential. However, BCR-mediated p38 MAPK
activation was abolished in Lyn/Syk double deficient cells, demonstrating that
either Lyn or Syk alone may be sufficient to activate p38 MAPK. Our data show
that BCR-mediated MAPK activation is regulated at the level of the PTKs.
PMID- 9763610
TI - Expression of interleukin 9 in the lungs of transgenic mice causes airway
inflammation, mast cell hyperplasia, and bronchial hyperresponsiveness.
AB - Interleukin (IL)-9, a pleiotropic cytokine produced by the Th2 subset of T
lymphocytes has been proposed as product of a candidate gene responsible for
asthma. Its wide range of biological functions on many cell types involved in the
allergic immune response suggests a potentially important role in the complex
pathogenesis of asthma. To investigate the contributions of IL-9 to airway
inflammation and airway hyperresponsiveness in vivo, we created transgenic mice
in which expression of the murine IL-9 cDNA was regulated by the rat Clara cell
10 protein promoter. Lung selective expression of IL-9 caused massive airway
inflammation with eosinophils and lymphocytes as predominant infiltrating cell
types. A striking finding was the presence of increased numbers of mast cells
within the airway epithelium of IL-9-expressing mice. Other impressive pathologic
changes in the airways were epithelial cell hypertrophy associated with
accumulation of mucus-like material within nonciliated cells and increased
subepithelial deposition of collagen. Physiologic evaluation of IL-9-expressing
mice demonstrated normal baseline airway resistance and markedly increased airway
hyperresponsiveness to inhaled methacholine. These findings strongly support an
important role for IL-9 in the pathogenesis of asthma.
PMID- 9763612
TI - The inositol polyphosphate 5-phosphatase ship is a crucial negative regulator of
B cell antigen receptor signaling.
AB - Ship is an Src homology 2 domain containing inositol polyphosphate 5-phosphatase
which has been implicated as an important signaling molecule in hematopoietic
cells. In B cells, Ship becomes associated with Fcgamma receptor IIB
(FcgammaRIIB), a low affinity receptor for the Fc portion of immunoglobulin
(Ig)G, and is rapidly tyrosine phosphorylated upon B cell antigen receptor (BCR)
FcgammaRIIB coligation. The function of Ship in lymphocytes was investigated in
Ship-/- recombination-activating gene (Rag)-/- chimeric mice generated from gene
targeted Ship-/- embryonic stem cells. Ship-/-Rag-/- chimeras showed reduced
numbers of B cells and an overall increase in basal serum Ig. Ship-/- splenic B
cells displayed prolonged Ca2+ influx, increased proliferation in vitro, and
enhanced mitogen-activated protein kinase (MAPK) activation in response to BCR
FcgammaRIIB coligation. These results demonstrate that Ship plays an essential
role in FcgammaRIIB-mediated inhibition of BCR signaling, and that Ship is a
crucial negative regulator of Ca2+ flux and MAPK activation.
PMID- 9763611
TI - Transgenic mice overexpressing the complement inhibitor crry as a soluble protein
are protected from antibody-induced glomerular injury.
AB - Complement receptor 1-related gene/protein y (Crry) is a potent murine membrane
complement regulator that inhibits classical and alternative pathway C3
convertases. In nephrotoxic serum (NTS) nephritis, injected antibodies (Abs) bind
to glomeruli, leading to complement activation and subsequent glomerular injury
and albuminuria. To study the phenotypic effects of continuous complement pathway
blockade, transgenic mice were created that express recombinant soluble (rs) Crry
directed by the broadly active and heavy metal-inducible metallothionein-I
promoter. One transgenic line expressing high levels of rsCrry was propagated.
Serum rsCrry levels were 18.7 +/- 2.7 microg/ml (n = 5) at basal level and
increased to 118.1 +/- 20.6 microg/ml 4 d after addition of zinc to the drinking
water. By reverse transcription polymerase chain reaction (RT-PCR), transgene
messenger (m)RNA was present in liver, kidney, brain, lung, and spleen, but not
in heart. By in situ RT-PCR analysis of kidneys, transgene mRNA was widely
expressed both in renal glomeruli and tubules. Urinary excretion of rsCrry was
113.4 +/- 22.4 microg/ml with a fractional excretion relative to creatinine of
13.2 +/- 2.7%, consistent with local renal production of rsCrry and secretion
into urine. The founder and all transgene positive adult animals have remained
healthy with no mortality or apparent phenotypic abnormalities, including
infection or immune complex disease. To determine whether rsCrry blocked
complement-mediated injury, NTS nephritis was induced by injection of NTS
immunoglobulin (Ig)G, followed by an 18-h urine collection to quantitate the
excretion of albumin as a measure of glomerular injury. In transgene-negative
littermates (n = 15), transgene-positive animals (n = 10), and transgene-positive
animals fed zinc (n = 10), albuminuria was 4,393 +/- 948, 1,783 +/- 454, and
1,057 +/- 277 microg/mg creatinine, respectively (P < 0.01 by ANOVA). Glomerular
C3 was evident by immunofluorescence staining in 12/15 transgene-negative
animals, but in none of the transgene-positive animals fed zinc. Thus, we have
produced the first transgenic animals that overexpress a soluble C3 convertase
inhibitor. rsCrry expression markedly ameliorates an Ab-induced disease model in
vivo. These results support the hypothesis that continuous complement inhibition
at the C3 convertase step is feasible and effective in complement-mediated injury
states.
PMID- 9763613
TI - A critical role of the p75 tumor necrosis factor receptor (p75TNF-R) in organ
inflammation independent of TNF, lymphotoxin alpha, or the p55TNF-R.
AB - Despite overwhelming evidence that enhanced production of the p75 tumor necrosis
factor receptor (p75TNF-R) accompanies development of specific human inflammatory
pathologies such as multi-organ failure during sepsis, inflammatory liver
disease, pancreatitis, respiratory distress syndrome, or AIDS, the function of
this receptor remains poorly defined in vivo. We show here that at levels
relevant to human disease, production of the human p75TNF-R in transgenic mice
results in a severe inflammatory syndrome involving mainly the pancreas, liver,
kidney, and lung, and characterized by constitutively increased NF-kappaB
activity in the peripheral blood mononuclear cell compartment. This process is
shown to evolve independently of the presence of TNF, lymphotoxin alpha, or the
p55TNF-R, although coexpression of a human TNF transgene accelerated pathology.
These results establish an independent role for enhanced p75TNF-R production in
the pathogenesis of inflammatory disease and implicate the direct involvement of
this receptor in a wide range of human inflammatory pathologies.
PMID- 9763614
TI - Inhibition of complement regulation is key to the pathogenesis of active Heymann
nephritis.
AB - Crry (complement receptor 1-related protein/gene y) is a key cellular complement
regulator in rodents. It is also present in Fx1A, the renal tubular preparation
used to immunize rats to induce active Heymann nephritis (HN), a model of
membranous nephropathy. We hypothesized that rats immunized with anti-Fx1A
develop autoantibodies (auto-Abs) to Crry as well as to the megalin-containing HN
antigenic complex, and that anti-Crry Abs promote the development of injury in HN
by neutralizing the complement regulatory activity of Crry. Rats immunized with
Fx1A lacking Crry remained free of proteinuria and glomerular deposits of C3
during a 10-wk follow-up despite typical granular immunoglobulin (Ig)G deposits
in glomeruli. Anti-Fx1A auto-Abs were present in their sera at levels that were
not different from sera pooled from proteinuric rats with HN induced with
nephritogenic Fx1A. Passive administration of sheep anti-Crry Abs to rats
immunized with Crry-deficient Fx1A led to proteinuria and glomerular C3
deposition, which were not seen in such rats injected with preimmune IgG, nor in
rats with collagen-induced arthritis injected with anti-Crry IgG. To directly
examine the role of Crry in HN, rats were immunized with Crry-deficient Fx1A
reconstituted with rCrry. This led to typical HN, with 8 out of 15 rats
developing proteinuria within 14 wk. Moreover, the extent of glomerular C3
deposition correlated with proteinuria, and anti-Crry Abs were present in
glomerular eluates. Thus, Crry is a key nephritogenic immunogen in Fx1A.
Formation of neutralizing auto-Abs to Crry impairs its function, leading to
unrestricted complement activation by Abs reactive with the HN antigenic complex
on the epithelial cell surface.
PMID- 9763615
TI - Immature dendritic cells phagocytose apoptotic cells via alphavbeta5 and CD36,
and cross-present antigens to cytotoxic T lymphocytes.
AB - Dendritic cells, but not macrophages, efficiently phagocytose apoptotic cells and
cross-present viral, tumor, and self-antigens to CD8(+) T cells. This in vitro
pathway corresponds to the in vivo phenomena of cross-priming and cross
tolerance. Here, we demonstrate that phagocytosis of apoptotic cells is
restricted to the immature stage of dendritic cell (DC) development, and that
this process is accompanied by the expression of a unique profile of receptors,
in particular the alphavbeta5 integrin and CD36. Upon maturation, these receptors
and, in turn, the phagocytic capacity of DCs, are downmodulated. Macrophages
engulf apoptotic cells more efficiently than DCs, and although they express many
receptors that mediate this uptake, they lack the alphavbeta5 integrin.
Furthermore, in contrast to DCs, macrophages fail to cross-present antigenic
material contained within the engulfed apoptotic cells. Thus, DCs use unique
pathways for the phagocytosis, processing, and presentation of antigen derived
from apoptotic cells on class I major histocompatibility complex. We suggest that
the alphavbeta5 integrin plays a critical role in the trafficking of exogenous
antigen by immature DCs in this cross-priming pathway.
PMID- 9763616
TI - The interleukin 2 receptor alpha chain/CD25 promoter is a target for nuclear
factor of activated T cells.
AB - The expression of the murine interleukin (IL)-2 receptor alpha chain/CD25 is
strongly induced at the transcriptional level after T cell activation. We show
here that nuclear factor of activated T cell (NF-AT) factors are involved in the
control of CD25 promoter induction in T cells. NF-ATp and NF-ATc bind to two
sites around positions -585 and -650 located upstream of the proximal CD25
promoter. Immediately 3' from these NF-AT motifs, nonconsensus sites are located
for the binding of AP-1-like factors. Mutations of sites that suppress NF-AT
binding impair the induction and strong NF-ATp-mediated transactivation of the
CD25 promoter in T cells. In T lymphocytes from NF-ATp-deficient mice, the
expression of CD25 is severely impaired, leading to a delayed IL-2 receptor
expression after T cell receptor (TCR)/CD3 stimulation. Our data indicate an
important role for NF-AT in the faithful expression of high affinity IL-2
receptors and a close link between the TCR-mediated induction of IL-2 and IL-2
receptor alpha chain promoters, both of which are regulated by NF-AT factors.
PMID- 9763617
TI - Essential and partially overlapping role of CD3gamma and CD3delta for development
of alphabeta and gammadelta T lymphocytes.
AB - CD3gamma and CD3delta are two highly related components of the T cell receptor
(TCR)-CD3 complex which is essential for the assembly and signal transduction of
the T cell receptor on mature T cells. In gene knockout mice deficient in either
CD3delta or CD3gamma, early thymic development mediated by pre-TCR was either
undisturbed or severely blocked, respectively, and small numbers of TCR
alphabeta+ T cells were detected in the periphery of both mice. gammadelta T cell
development was either normal in CD3delta-/- mice or partially blocked in
CD3gamma-/- mice. To examine the collective role of CD3gamma and CD3delta in the
assembly and function of pre-TCR and in the development of gammadelta T cells, we
generated a mouse strain with a disruption in both CD3gamma and CD3delta genes
(CD3gammadelta-/-). In contrast to mice deficient in either CD3gamma or CD3delta
chains, early thymic development mediated by pre-TCR is completely blocked, and
TCR-alphabeta+ or TCR-gammadelta+ T cells were absent in the CD3gammadelta-/-
mice. Taken together, these studies demonstrated that CD3gamma and CD3delta play
an essential, yet partially overlapping, role in the development of both
alphabeta and gammadelta T cell lineages.
PMID- 9763618
TI - Stimulus-dependent synergism of the antiapoptotic tumor necrosis factor receptor
associated factor 2 (TRAF2) and nuclear factor kappaB pathways.
AB - Tumor necrosis factor (TNF) signaling leads to pleiotropic responses in a wide
range of cell types, in part by activating antiapoptotic and proapoptotic
signaling pathways. Thus, although TNF can cause apoptosis and may prove useful
in the treatment of malignancies, most cells are resistant to TNF-induced cell
death unless de novo protein synthesis is inhibited. Previous studies suggested
that TNF activation of the nuclear factor (NF)-kappaB transcription factor family
antagonizes the proapoptotic signals initiated by TNF-alpha. TNF receptor
associated factor (TRAF)2 has also been shown to mediate crucial antiapoptotic
signals during TNF stimulation, yet is not essential in activation of NF-kappaB
under physiologic conditions, thus raising questions about the relationship
between these antiapoptotic pathways. We report here that inhibition of TRAF2 and
NF-kappaB function in primary cells, by coexpression of a constitutive repressor
of multiple NF-kappaB/Rel proteins (IkappaBalpha.DN) and a dominant negative form
of TRAF2 (TRAF2.DN), synergistically enhanced TNF-induced apoptosis. The effects
were stimulus dependent, such that neither inhibitory molecule affected Fas- and
daunorubicin-induced apoptosis to the same degree as TNF-induced death. These
findings indicate that the NF-kappaB and TRAF2 pathways activate independent
antiapoptotic mechanisms which act in concert to suppress the proapoptotic
signals induced by TNF-alpha.
PMID- 9763619
TI - Regulation of L-selectin-mediated rolling through receptor dimerization.
AB - L-selectin binding activity for its ligand expressed by vascular endothelium is
rapidly and transiently increased after leukocyte activation. To identify
mechanisms for upregulation and assess how this influences leukocyte/endothelial
cell interactions, cell-surface dimers of L-selectin were induced using the
coumermycin-GyrB dimerization strategy for cross-linking L-selectin cytoplasmic
domains in L-selectin cDNA-transfected lymphoblastoid cells. Coumermycin- induced
L-selectin dimerization resulted in an approximately fourfold increase in binding
of phosphomanan monoester core complex (PPME), a natural mimic of an L-selectin
ligand, comparable to that observed after leukocyte activation. Moreover, L
selectin dimerization significantly increased (by approximately 700%) the number
of lymphocytes rolling on vascular endothelium under a broad range of
physiological shear stresses, and significantly slowed their rolling velocities.
Therefore, L-selectin dimerization may explain the rapid increase in ligand
binding activity that occurs after leukocyte activation and may directly
influence leukocyte migration to peripheral lymphoid tissues or to sites of
inflammation. Inducible oligomerization may also be a common mechanism for
rapidly upregulating the adhesive or ligand-binding function of other cell
surface receptors.
PMID- 9763620
TI - Muscle geometry.
PMID- 9763621
TI - The generation of directionally selective responses in the retina.
PMID- 9763622
TI - An ether -a-go-go K+ current, Ih-eag, contributes to the hyperpolarization of
human fusion-competent myoblasts.
AB - 1. Two early signs of human myoblast commitment to fusion are membrane potential
hyperpolarization and concomitant expression of a non-inactivating delayed
rectifier K+ current, IK(NI). This current closely resembles the outward K+
current elicited by rat ether-a-go-go (r-eag) channels in its range of potential
for activation and unitary conductance. 2. It is shown that activation kinetics
of IK(NI), like those of r-eag, depend on holding potential and on [Mg2+]o, and
that IK(NI), like r-eag, is reversibly inhibited by a rise in [Ca2+]i. 3. Forced
expression of an isolated human ether-a-go-go K+ channel (h-eag) cDNA in
undifferentiated myoblasts generates single-channel and whole-cell currents with
remarkable similarity to IK(NI). 4. h-eag current (Ih-eag) is reversibly
inhibited by a rise in [Ca2+]i, and the activation kinetics depend on holding
potential and [Mg2+]o. 5. Forced expression of h-eag hyperpolarizes
undifferentiated myoblasts from -9 to -50 mV, the threshold for the activation of
both Ih-eag and IK(NI). Similarly, the higher the density of IK(NI), the more
hyperpolarized the resting potential of fusion-competent myoblasts. 6. It is
concluded that h-eag constitutes the channel underlying IK(NI) and that it
contributes to the hyperpolarization of fusion-competent myoblasts. To our
knowledge, this is the first demonstration of a physiological role for a
mammalian eag K+ channel.
PMID- 9763623
TI - Separable effects of human Kvbeta1.2 N- and C-termini on inactivation and
expression of human Kv1.4.
AB - 1. The Kvbeta subunits of voltage-gated K+ channels alter the functional
expression and gating of non- or slowly inactivating Kvalpha1 subunits via two
separate domains. To determine how Kvbeta subunits modulate a rapidly
inactivating Kvalpha1 subunit, we did two-microelectrode voltage clamp
experiments on human Kv1.4 voltage-gated K+ channels expressed heterologously in
Xenopus oocytes. In addition we tested a slowly inactivating mutant of Kv1.4
lacking amino acids 2-146 of the N-terminal alpha-ball domain (Kv1. 4DeltaN2
146). Kv1.4 or Kv1.4DeltaN2-146 were co-expressed with either rat Kvbeta2 or
human Kvbeta1.2. To separate domain effects, we also used a mutant of Kvbeta1.2
lacking the unique 79 amino acid N-terminal beta-ball domain (Kvbeta1-C). 2. For
the mutant Kv1.4DeltaN2-146 we found that Kvbeta1-C or Kvbeta2 increased current
amplitude without altering activation or inactivation. By contrast Kvbeta1.2
produced rapid inactivation and slowed deactivation due to block produced by the
beta-ball. The beta-ball also increased the rate of C-type inactivation in 5 mM,
but not 50 mM, external K+ consistent with an effect of blockade on K+ efflux. 3.
For Kv1.4, Kvbeta1-C produced a voltage-independent increase in the rate of
inactivation and shifted the inactivation curve to more hyperpolarized
potentials, but had no effect on deactivation. Kvbeta1-C, Kvbeta2 and Kvbeta1.2
slowed recovery from inactivation similarly, thereby excluding involvement of the
beta-ball. Kvbeta1.2 produced an additional more rapid, voltage-dependent
component of inactivation, significantly reduced peak outward current and shifted
steady-state inactivation towards hyperpolarized potentials. 4. Yeast two-hybrid
studies showed that alpha-beta interaction was restricted to the N-terminus of
Kv1.4 and the C-terminus of Kvbeta1. 2 or Kvbeta2. Direct interaction with the
alpha-ball did not occur. Our interpretation is that Kvbeta1-C and Kvbeta2
enhanced N-type inactivation produced by the Kv1.4 alpha-ball allosterically. 5.
We propose that Kvbeta1.2 has three effects on Kv1.4, the first two of which it
shares with Kvbeta2. First, Kvbeta1-C and Kvbeta2 have a current-enhancing
effect. Second, Kvbeta1-C and Kvbeta2 increase block by the alpha-ball
allosterically. Third, the beta-ball of Kbeta1.2 directly blocks both Kv1.4 and
Kv1.4DeltaN2-146. When both alpha- and beta-balls are present, competition for
their respective binding sites slows the block produced by either ball.
PMID- 9763624
TI - Fibre type-specific gene expression activated by chronic electrical stimulation
of adult mouse skeletal muscle fibres in culture.
AB - 1. Fast-twitch skeletal muscle fibres were enzymatically dissociated from adult
mouse flexor digitorum brevis (FDB) muscles and maintained in culture without or
with chronic low frequency stimulation (one 5 s train of 5 Hz pulses per minute)
for up to 6 days. Single fibre reverse transcriptase-polymerase chain reaction
was conducted to coamplify beta-myosin heavy chain (beta-MHC) and alpha-skeletal
actin mRNA from the same fibre. 2. Chronic low frequency electrical stimulation
of FDB fibres in culture increased the level of mRNA for beta-MHC. In
unstimulated fibres there was a slight decline in the beta-MHC mRNA level. As an
internal control there was no increase in the level of mRNA for alpha-actin in
the identical individual stimulated or unstimulated fibres. 3. Neither the
percentage of fibres exhibiting beta-MHC protein nor the Ca2+ transients recorded
from individual fibres subjected to the same pattern of stimulation showed any
difference between stimulated and unstimulated fibres over the period in culture.
4. This system provides a convenient in vitro model system for studying activity
dependent control of fibre type-specific gene expression in adult skeletal muscle
fibres in culture.
PMID- 9763625
TI - Thiophosphorylation of myosin light chain increases rigor stiffness of rabbit
smooth muscle.
AB - 1. The effect of thiophosphorylation of the regulatory myosin light chain (MLC20)
on rigor stiffness was determined in permeabilized rabbit bladder smooth muscle.
2. Rigor stiffness of alpha-toxin-permeabilized smooth muscle was significantly
increased by thiophosphorylation of MLC20. This increase may have been due to
partial shortening (melting) in the proximal rod region and/or stiffening of the
regulatory domain of the myosin head. 3. We suggest that phosphorylation of
MLC20, by increasing the stiffness of the S1 lever arm and/or S2 hinge regions of
the myosin molecule, favours separation of the two phosphorylated heads and
consequent deinhibition of motor domain activity.
PMID- 9763626
TI - Chronic hypoxia reduces adenosine A2A receptor-mediated inhibition of calcium
current in rat PC12 cells via downregulation of protein kinase A.
AB - 1. Adenosine has been shown to decrease Ca2+ current (ICa) and attenuate the
hypoxia-induced enhancement of intracellular free Ca2+ ([Ca2+]i) in oxygen
sensitive rat phaeochromocytoma (PC12) cells. These effects are mediated via the
adenosine A2A receptor and protein kinase A (PKA). The current study was
undertaken to determine the effects of adenosine on Ca2+ current and hypoxia
induced change in [Ca2+]i during chronic hypoxia. 2. Whole cell patch-clamp
studies revealed that the effect of adenosine on ICa was significantly reduced
when PC12 cells were exposed to hypoxia (10 % O2) for 24 and 48 h. 3. Ca2+
imaging studies using fura-2 revealed that the anoxia-induced increase in [Ca2+]i
was significantly enhanced when PC12 cells were exposed to 10 % O2 for up to 48
h. In contrast, the inhibitory effects of adenosine on anoxia-induced elevation
of [Ca2+]i was significantly blunted in PC12 cells exposed to hypoxia for 48 h.
4. Northern blot analysis revealed that mRNA for the A2A receptor, which is the
only adenosine receptor subtype expressed in PC12 cells, was significantly
upregulated by hypoxia. Radioligand binding analysis with [3H]CGS21680, a
selective A2A receptor ligand, showed that the number of adenosine A2A receptor
binding sites was similarly increased during exposure to 10% O2 for 48 h. 5. PKA
enzyme activity was significantly inhibited when PC12 cells were exposed to 10%
O2 for 24 and 48 h. However, we found that hypoxia failed to induce change in
adenosine- and forskolin-stimulated adenylate cyclase enzyme activity. Chronic
hypoxia also did not alter the immunoreactivity level of the G protein Gsalpha,
an effector of the A2 signalling pathway. 6. Whole cell patch-clamp analysis
showed that the effect of 8-bromo-cAMP, an activator of PKA, on ICa was
significantly attenuated during 48 h exposure to 10% O2.7. We conclude therefore
that the reduced effect of adenosine on ICa and [Ca2+]i in PC12 cells exposed to
chronic hypoxia is due to hypoxia-induced downregulation of PKA. This mechanism
may serve to reduce the negative feedback on ICa and [Ca2+]i by adenosine and
therefore maintain enhanced membrane excitability of PC12 cells during long-term
hypoxia.
PMID- 9763627
TI - Contrasting Ca2+ channel subtypes at cell bodies and synaptic terminals of rat
anterioventral cochlear bushy neurones.
AB - 1. Whole-cell patch clamp recordings were made from bushy cells of the
anterioventral cochlear nucleus (aVCN) and their synaptic terminals (calyx of
Held) in the medial nucleus of the trapezoid body (MNTB). 2. Both high voltage
activated (HVA) and low voltage-activated (LVA) calcium currents were present in
acutely dissociated aVCN neurones and in identified bushy neurones from a
cochlear nucleus slice. 3. The transient LVA calcium current activated rapidly on
depolarization (half-activation, -59 mV) and inactivated during maintained
depolarization (half-inactivation, -89 mV). This T-type current was observed in
somatic recordings but was absent from presynaptic terminals. 4. On the basis of
their pharmacological sensitivity, P/Q-type Ca2+ channels accounted for only 6 %
of the somatic HVA, while L-, N- and R-type Ca2+ channels each accounted for
around one-third of the somatic calcium current. 5. The divalent permeabilities
of these native calcium channels were compared. The Ba2+/Ca2+ conductance ratios
of the somatic HVA and LVA channels were 1.4 and 0.7, respectively. The
conductance ratio of the presynaptic HVA current was 0.9, significantly lower
that that of the somatic HVA current. 6. We conclude that LVA currents are
expressed in the bushy cell body, but are not localized to the excitatory
synaptic terminal. All of the HVA current subtypes are expressed in bushy cells,
but there is a strong polarity to their localization; P-type contribute little to
somatic currents but predominate at the synaptic terminal; L-, N- and R-types
dominate at the soma, but contribute negligibly to calcium currents in the
terminal.
PMID- 9763628
TI - Local calcium release in mammalian skeletal muscle.
AB - 1. Fluo-3 fluorescence associated with Ca2+ release was recorded with confocal
microscopy in single muscle fibres mechanically dissected from fast twitch muscle
of rats or frogs, voltage clamped in a two Vaseline-gap chamber. 2. Interventions
that elicited Ca2+ sparks in frog skeletal muscle (low voltage depolarizations,
application of caffeine) generated in rat fibres images consistent with
substantial release from triadic regions, but devoid of resolvable discrete
events. Ca2+ sparks were never observed in adult rat fibres. In contrast, sparks
of standard morphology were abundant in myotubes from embryonic mice. 3.
Depolarization-induced gradients of fluorescence between triadic and surrounding
regions (which are proportional to Ca2+ release flux) peaked at about 20 ms and
then decayed to a steady level. Gradients were greater in frog fibres than in rat
fibres. The ratio of peak over steady gradient (R) was steeply voltage dependent
in frogs, reaching a maximum of 4.8 at -50 mV (n = 7). In rats, R had an
essentially voltage-independent value of 2.3 (n = 5). 4. Ca2+-induced Ca2+
release, resulting in concerted opening of several release channels, is thought
to underlie Ca2+ sparks and the peak phase of release in frog skeletal muscle. A
diffuse 'small event' release, similar to that observed in these rats, is also
present in frogs and believed to be directly activated by voltage. The present
results suggest that in these rat fibres there is little contribution by CICR to
Ca2+ release triggered by depolarization, and a lack of concerted channel
opening.
PMID- 9763629
TI - alpha-adrenergic stimulation of cytosolic Ca2+ oscillations and exocytosis in
identified rat corticotrophs.
AB - 1. The patch clamp technique was used in conjunction with a fluorescent Ca2+
indicator (indo-1, or indo-1FF) to measure simultaneously cytosolic Ca2+
concentration ([Ca2+]i), ionic current and changes in membrane capacitance in
single rat corticotrophs identified with the reverse haemolytic plaque assay. 2.
Application of the adrenocorticotropin (ACTH) secretagogue noradrenaline (NA;
norepinephrine), triggered [Ca2+]i oscillation in corticotrophs via alpha
adrenergic receptors and the guanosine trisphosphate (GTP) binding protein
coupled phosphoinositide pathway. 3. Simultaneous measurement of [Ca2+]i and
capacitance shows that exocytosis was triggered during the first cycle of NA
induced [Ca2+]i oscillation and the mean increase in cell membrane surface area
was 1.4 +/- 0.3 % (n = 6). 4. When Ca2+ was directly released from the inositol
1,4, 5 trisphosphate (IP3)-sensitive store via flash photolysis of caged IP3, the
mean increase in cell surface area was 1.5 +/- 0.5 % (n = 6). Thus, NA-stimulated
ACTH secretion in rat corticotrophs is closely coupled to intracellular Ca2+
release. 5. Large and rapid elevation of [Ca2+]i (>15 microM) via flash
photolysis of caged Ca2+ triggered two phases of exocytosis: a rapid exocytic
burst that was complete in approximately 100 ms and a slow burst that continued
for many seconds. 6. The rapid exocytic burst reflected the exhaustion of a pool
of readily releasable granules and, on average, increased the cell surface by 2.8
+/- 0.1 % (n = 14). 7. We suggest that the relatively weak exocytic response in
corticotrophs during intracellular Ca2+ release may be partially attributed to a
smaller pool of readily releasable granules.
PMID- 9763630
TI - Cytoplasmic terminus domains of Kir6.x confer different nucleotide-dependent
gating on the ATP-sensitive K+ channel.
AB - 1. In order to investigate the structural basis for the nucleotide-dependent
gating of ATP-sensitive K+ channels (KATP), Kir6.1 (uKATP-1), Kir6.2 (BIR1) and
chimeric channels were co-expressed with a common subtype of sulphonylurea
receptor, SUR1, in COS7 cells. Representing the amino terminal domain
transmembrane domain-carboxyl-terminal domain of Kir6.1 as 1-1-1 and of Kir6.2 as
2-2-2, chimeric Kir6.x channels were constructed by swapping the amino and/or
carboxyl terminal domains between Kir6.1 and Kir6.2 to give the chimeric x-1-x
channels 1-1-2, 2-1-1 and 2-1-2, and the chimeric x-2-x channels 2-2-1, 1-2-2 and
1-2-1. 2. Inside-out patch clamp experiments revealed that both wild-type Kir6.1
and Kir6.2 formed inwardly rectifying K+ channels. Single-channel conductances
were 36.3 and 66.1 pS, respectively. Chimeric x-1-x channels, whose transmembrane
domain was that of Kir6.1, showed similar ion-pore properties to wild-type
Kir6.1. Likewise, chimeric x-2-x channels had similar ion-pore properties to wild
type Kir6.2. 3. Wild-type Kir6.1 and Kir6.2 possessed distinct gating properties
towards intracellular nucleotides. The activity of Kir6.1 was entirely dependent
on Mg2+ and nucleotide diphosphates (NDPs) such as UDP. In contrast, Kir6.2 was
activated upon excision of patch membrane. When Kir6.2 underwent rundown, UDP
reactivated the channel. 4. In order to eliminate UDP dependence from Kir6.1, it
was necessary to replace both N- and C-termini; chimera 2-1-2 opened in UDP-free
conditions. With Kir6.2, substitution of the N-terminus with that of Kir6.1
conferred UDP dependence on chimeras 1-2-2 and 1-2-1. Chimera 2-2-1 opened in UDP
free conditions, but UDP potentiated the channel activity by > 20-fold. 5. The
kinetics of UDP-dependent activation were significantly different between Kir6.1
and Kir6.2. Kir6.1 maximally activated by UDP was sensitive to intracellular ATP,
although its ATP sensitivity was significantly lower than that of Kir6.2 measured
in identical conditions. The kinetics of UDP-dependent activation and ATP
sensitivity could be transferred between Kir6.1 and Kir6.2 only when both N- and
C-termini were replaced. We therefore concluded that nucleotide-dependent gating
was regulated by the N- and C-terminal domains irrespective of the transmembrane
domains.
PMID- 9763632
TI - Anoxia differentially modulates multiple K+ currents and depolarizes neonatal rat
adrenal chromaffin cells.
AB - 1. Using perforated-patch, whole cell recording, we investigated the membrane
mechanisms underlying O2 chemosensitivity in neonatal rat adrenomedullary
chromaffin cells (AMC) bathed in extracellular solution containing tetrodotoxin
(TTX; 0.5-1 microM), with or without blockers of calcium entry. 2. Under voltage
clamp, low PO2 (0-15 mmHg) caused a graded and reversible suppression in
macroscopic outward K+ current. The suppression during anoxia (PO2 = 0 mmHg) was
approximately 35% (voltage step from -60 to +30 mV) and was due to a combination
of several factors: (i) suppression of a cadmium-sensitive, Ca2+-dependent K+
current, IK(CaO2); (ii) suppression of a Ca2+-insensitive, delayed rectifier type
K+ current, IK(VO2); (iii) activation of a glibenclamide- (and Ca2+)-sensitive
current, IK(ATP). 3. During normoxia (PO2 = 150 mmHg), application of pinacidil
(100 microM), an ATP-sensitive potassium channel (KATP) activator, increased
outward current density by 45.0 +/- 7.0 pA pF-1 (step from -60 to + 30 mV),
whereas the KATP blocker glibenclamide (50 microM) caused only a small
suppression by 6.3 +/- 4.0 pA pF-1. In contrast, during anoxia the presence of
glibenclamide resulted in a substantial reduction in outward current density by
24.9 +/- 7.9 pA pF-1, which far exceeded that seen in its absence. Thus,
activation of IK(ATP) by anoxia appears to reduce the overall K+ current
suppression attributable to the combined effects of IK(CaO2) and IK(VO2). 4.
Pharmacological tests revealed that IK(CaO2) was carried predominantly by maxi-K+
or BK potassium channels, sensitive to 50-100 nM iberiotoxin; this current also
accounted for the major portion (approximately 60%) of the anoxic suppression of
outward current. Tetraethylammonium (TEA; 10-20 mM) blocked all of the anoxia
sensitive K+ currents recorded under voltage clamp, i.e. IK(CaO2), IK(VO2) and
IK(ATP). 5. Under current clamp, anoxia depolarized neonatal AMC by 10-15 mV from
a resting potential of approximately -55 mV. At least part of this depolarization
persisted in the presence of either TEA, Cd2+, 4-aminopyridine or charybdotoxin,
suggesting the presence of anoxia-sensitive mechanisms additionalto those
revealed under voltage clamp. In Na+/Ca2+-free solutions, the membrane
hyperpolarized, though at least a portion of the anoxia-induced depolarization
persisted. 6. In the presence of glibenclamide, the anoxia-induced depolarization
increased significantly to approximately 25 mV, suggesting that activation of
KATP channels may function to attenuate the anoxia-induced depolarization or
receptor potential.
PMID- 9763631
TI - Non-receptor-mediated activation of IK(ATP) and inhibition of IK(ACh) by
diadenosine polyphosphates in guinea-pig atrial myocytes.
AB - 1. The effects of diadenosine polyphosphates (APnA, where n = 4-6) were studied
on beating frequency of perfused guinea-pig hearts and on muscarinic K+ current
(IK(ACh)) and ATP-regulated K+ current (IK(ATP)) in atrial myocytes from guinea
pig hearts using whole-cell voltage clamp. 2. Bradycardia induced by APnA in
perfused hearts was completely inhibited by 8-cyclopentyl- 1,3-dipropylxanthine
(CPX, 20 microM), a selective antagonist at A1 adenosine receptors, and was
augmented by dipyridamole (Dipy), an inhibitor of cellular adenosine (Ado)
uptake. 3. Whereas exposure of atrial myocytes to Ado (100 microM) within about 1
s induced a significant whole-cell IK(ACh), APnA up to 1 mM applied for some tens
of seconds failed to activate IK(ACh). If present for periods > 2 min, APnA
caused inhibition of agonist-evoked IK(ACh) and activation of a weakly inward
rectifying K+ current, which was identified as IK(ATP) by its sensitivity to
glibenclamide and its current-voltage curve. 4. The actions of extracellular APnA
on IK(ACh) and IK(ATP) were mimicked by intracellular loading of compounds via
the patch clamp pipette and by intracellular loading of AMP. 5. The results from
isolated myocytes exclude APnA acting as A1 agonists. It is suggested that
myocytes can take up APnA, which are degraded to AMP. In the presence of ATP, AMP
is converted to ADP, a physiological activator of ATP-regulated K+ channels, by
adenylate kinase. A similar mechanism resulting in a reduction of the [GTP]/[GDP]
ratio might be responsible for inhibition of IK(ACh). 6. In the perfused heart
and other multicellular cardiac preparations the actions of APnA are mediated by
Ado via A1 receptors. It is suggested that APnA in multicellular cardiac tissue
are hydrolysed by an ectohydrolase to yield AMP which is converted to Ado by
ectonucleotidases.
PMID- 9763633
TI - Involvement of PKC-alpha in regulatory volume decrease responses and activation
of volume-sensitive chloride channels in human cervical cancer HT-3 cells.
AB - 1. The present study was carried out to identify the specific protein kinase C
(PKC) isoform involved in regulatory volume decrease (RVD) responses, and to
investigate the signal transduction pathways underlying the activation of volume
sensitive chloride channels in human cervical cancer HT-3 cells. The role of Ca2+
in RVD and in the activation of chloride currents was also studied. 2. The time
course of RVDs was prolonged by microinjection of PKC-alpha antibody but not by
PKC-beta or PKC-gamma antibody, and also by exposure to Ca2+-free medium, in
particular when combined with microinjection of EDTA. Immunofluorescence staining
showed that hypotonic superfusion evoked the translocation of PKC-alpha to the
cell membrane, whereas PKC-beta or PKC-gamma remained unaffected. The
translocation of PKC-alpha was observed a few minutes after hypotonic stress,
reaching peak intensity at 30 min, and returned to the cytoplasm 60 min after
hypotonic exposure. Western blot analyses showed an increased PKC-alpha level in
terms of intensity and phosphorylation in the cell membrane, while neither PKC
beta nor PKC-gamma was activated upon hyposmotic challenge. 3. Whole-cell patch
clamp studies demonstrated that neomycin and PKC blockers such as staurosporine
and H7 inhibited volume-sensitive chloride currents. The inhibitory effect of
neomycin on chloride currents can be reversed by the PKC activator phorbol 12
myristate, 13-acetate (PMA). Moreover, the PKC inhibitor and PKC-alpha antibody,
but not PKC-beta or PKC-gamma antibody, significantly attenuated the chloride
currents. The activation of volume-sensitive chloride currents were insensitive
to the changes of intracellular Ca2+ but required the presence of extracellular
Ca2+. 4. Our results suggest the involvement of PKC-alpha and extracellular Ca2+
in RVD responses and the activation of volume-sensitive chloride channels in HT-3
cells.
PMID- 9763634
TI - Sodium pump evokes high density pump currents in rat midbrain dopamine neurons.
AB - 1. Patch pipettes contained various concentrations of Na+ ([Na+]pip) in order to
record strophanthidin-sensitive currents under voltage clamp in dopamine neurons
in slices of rat substantia nigra and ventral tegmental area. 2. When [Na+]pip
was 40 mM and the external K+ concentration ([K+]o) was 2.5 mM, strophanthidin
(10 microM) evoked 461 +/- 121 pA of inward current. This effect was
concentration dependent, with an EC50 of 7.1 +/- 2.6 microM. At potentials of -60
to -120 mV, strophanthidin-induced currents were not associated with significant
changes in chord conductance. 3. Strophanthidin (10 microM) evoked 234 +/- 43 pA
of inward current when [Na+]pip was 0.6 mM, and 513 +/- 77 pA when [Na+]pip was
80 mM. Despite higher pump currents with greater [Na+]pip, the strophanthidin
EC50 was not significantly different for any of six different [Na+]pip. 4. Sodium
pump currents were half-maximal when the [Na+]pip was about 1.3 mM. Maximum pump
current was estimated at 830 pA (29 microA cm-2) at concentrations of
intracellular Na+ that were assumed to be saturating (50-100 mM). 5.
Strophanthidin currents were smaller in a reduced [K+]o (EC50 = 0.2 mM). 6. These
data show that intracellular Na+ loading evokes relatively large pump currents.
Our results are consistent with the physiological role of the sodium pump in
burst firing in midbrain dopamine neurons
PMID- 9763635
TI - Acid/base transport across the leech giant glial cell membrane at low external
bicarbonate concentration.
AB - 1. We have studied acid/base transport across the cell membrane of the giant
neuropile glial cell in the leech (Hirudo medicinalis) central nervous system
induced by changing the external pH (pHo), using double-barrelled, pH-sensitive
microelectrodes. In the presence of 5 % CO2 and 24 mM HCO3-, the intracellular pH
(pHi) rapidly changes due to a potent, reversible Na+-HCO3- cotransport across
the glial membrane. We have now investigated the transport mechanism which leads
to pHi changes in the nominal absence of CO2/HCO3-, where the HCO3- concentration
is expected to be below 1 mM. 2. The intracellular pH increased and then
decreased when pHo was altered from 7.4 to 7.8 and then 7.0 with a rate of
increase of +0.026 +/- 0.008 and a rate of decrease of -0.028 +/- 0.009 pH units
min-1 (+/- s.d., n = 49), indicating an acid/base flux rate of 0.64 and 0.71 mM
min-1 across the glial membrane, respectively. 3. In the absence of external
sodium (Na+replaced by N-methyl-D-glucamine), pHi slowly decreased, and the rate
of alkali and acid loading was reduced to 19 and 28 %, respectively, (n = 12).
Amiloride (2 mM), which inhibits Na+-H+ exchange, had no effect on the
alkali/acid loading (n = 6). 4. The alkali and acid loading were not impaired
after the removal of external chloride (Cl-o, replaced by gluconate; n = 11), but
were significantly reduced by the anion transport inhibitor 4,4'
diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS, 0.5 mM) to 23 and 16 %,
respectively, of the control (P < 0.001; n = 5). 5. Alkali and acid loading were
affected differently by manipulating the availability of residual HCO3-. After
adding the membrane-permeable carbonic anhydrase inhibitor ethoxyzolamide (EZA, 2
microM) to the saline, the acid loading, but not the alkali loading, was
significantly reduced (by 25 %, P < 0.01), while lowering the residual CO2/HCO3-
concentration in the saline by O2 bubbling significantly reduced the alkali
loading (by 59 %, P < 0. 02), but not the acid loading. 6. Changing the membrane
holding potential in voltage-clamped glial cells or raising the external K+
concentration to 30 mM had no significant effect on acid/base loading. 7. It is
concluded that a residual HCO3- concentration of less than 1 mM in nominally
CO2/HCO3--free salines and HCO3- produced endogenously in the glial cells support
alkali and acid loading across the glial cell membrane, presumably by activation
of the reversible Na+-HCO3- cotransporter. The results suggest a very high
selectivity and affinity of this cotransporter for HCO3-; they imply that HCO3-
dependent processes may not be negligible even in the nominal absence of CO2/HCO3
, when the HCO3- concentration is expected to be in the submillimolar range.
PMID- 9763637
TI - Integrin and cytoskeletal involvement in signalling cell volume changes to
glutamine transport in rat skeletal muscle.
AB - 1. Muscle glutamine transport is modulated in response to changes in cell volume
by a mechanism dependent on active phosphatidylinositol 3-kinase. We investigated
the possibility that this mechanism requires interactions between the
extracellular matrix (ECM), integrins and the cytoskeleton as components of a
mechanochemical transduction system. 2. Using skeletal muscle cells, we studied
effects of (a) inactivating integrin-substratum interactions by using integrin
binding peptide GRGDTP with inactive peptide GRGESP as control, and (b)
disrupting the cytoskeleton using colchicine or cytochalasin D, on glutamine
transport after brief exposure to hypo-osmotic, isosmotic or hyperosmotic medium
(170, 300 and 430 mosmol kg-1, respectively). 3. Neither GRGDTP nor GRGESP
significantly affected basal glutamine uptake (0.05 mM; 338 +/- 58 pmol min-1 (mg
protein)-1) but GRGDTP specifically prevented the increase (71%) and decrease
(39%) in glutamine uptake in response to hypo- and hyperosmotic exposure,
respectively. 4. Colchicine and cytochalasin D prevented the increase and
decrease in glutamine uptake in response to changes in external osmolality. They
also increased basal glutamine uptake by 59 +/- 19 and 85 +/- 16%, respectively,
in a wortmannin-sensitive manner. 5. These results indicate involvement of ECM
integrin-mediated cell adhesion and the cytoskeleton in mechanochemical
transduction of cell volume changes to chemical signals modulating glutamine
transport in skeletal muscle. Phosphatidylinositol 3-kinase may function to
maintain the mechanotransducer in an active state.
PMID- 9763636
TI - Regulated anion secretion in cultured epithelia from Sertoli cells of immature
rats.
AB - 1. Cultured epithelia of Sertoli cells from prepubertal rats were grown on
Matrigel-coated millipore filters for short-circuit current (Isc) measurements.
Under basal conditions, these epithelia exhibited a 'zero' transepithelial
potential difference, a 'zero' short-circuit current and a transepithelial
resistance of 60 Omega cm2. 2. Forskolin (100 microM) and 8-(4-chlorophenylthio)
cAMP (cpt-cAMP) (100 microM) added to the apical side stimulated the Isc
(forskolin, peak DeltaIsc = 1.32 +/- 0.16 microA cm-1; cpt-cAMP, peak DeltaIsc =
0.88 +/- 0.16 microA cm-2). 3. ATP (100 microM) added apically elicited a Isc
response (peak DeltaIsc = 6.45 +/- 0. 28 microA cm-2) which was similar in
magnitude to that of 1 microM thapsigargin (peak DeltaIsc = 6.09 +/- 0.44 microA
cm-2). The potency of the responses to other nucleotides: UTP >= ATP > ADP >> AMP
= adenosine indicates the involvement of a mixture of P2Y receptors. 4. Removal
of extracellular Cl- and HCO3- reduced the Isc response to ATP by 70 % and 40 %,
respectively. Removal of K+ had no effect, whereas removal of Na+ attenuated the
Isc response. 5. The response to ATP was insensitive to agents known to block
anion secretion (except apical diphenylamine-2-carboxylate (DPC) and DIDS). The
resistance to perturbation by pharmacological agents may be a unique property of
the seminiferous epithelium. 6. Whole-cell current recordings in cultured rat
Sertoli cells demonstrated a DIDS-sensitive outwardly rectifying Cl- conductance
with activating and inactivating characteristics at depolarizing and
hyperpolarizing voltages, respectively. 7. The stimulation of electrogenic ion
transport by ATP may be part of a complex mechanism regulating fluid secretion by
the testis. Cultured Sertoli cell epithelia are shown to provide a useful model
to investigate transepithelial transport in the seminiferous epithelium.
PMID- 9763638
TI - Effects of noradrenaline on intracellular pH in acutely dissociated adult rat
hippocampal CA1 neurones.
AB - 1. We examined the effects of noradrenaline on steady-state intracellular pH
(pHi) and the recovery of pHi from internal acid loads imposed by the NH4+
prepulse technique in hippocampal CA1 neurones acutely dissociated from adult
rats. 2. Under nominally HCO3--free conditions, acid extrusion was accomplished
by a Na+-dependent mechanism, probably the amiloride-insensitive variant of the
Na+-H+ exchanger previously characterized in both fetal and adult rat hippocampal
neurones. In the presence of external HCO3-, acid extrusion appeared to be
supplemented by a Na+-dependent HCO3--Cl- exchanger, the activity of which was
dependent upon the absolute level of pHi. 3. Noradrenaline evoked a concentration
dependent and sustained rise in steady-state pHi and increased rates of pHi
recovery from imposed intracellular acid loads. The effects of noradrenaline were
not dependent upon the presence of external HCO3- but were blocked by
substituting external Na+ with N-methyl-D-glucamine, suggesting that
noradrenaline acts to increase steady-state pHi by increasing the activity of the
Na+-H+ exchanger. 4. The effects of noradrenaline on steady-state pHi and on
rates of pHi recovery from imposed acid loads were mimicked by beta1- and beta2-,
but not alpha-, adrenoceptor agonists. The beta-adrenoceptor antagonist
propranolol blocked the ability of noradrenaline to increase both steady-state
pHi and rates of pHi recovery from acid loads. 5. The effects of noradrenaline on
steady-state pHi and on pHi recovery rates following acid loads were not
dependent on changes in [Ca2+]i. However, the effects of noradrenaline were
blocked by pre-treatment with the adenylate cyclase inhibitor 2',5'
dideoxyadenosine and the cAMP-dependent protein kinase inhibitors Rp-adenosine
3',5'-cyclic monophosphorothioate (sodium salt; Rp-cAMPS) and N-[2-(p
bromocinnamylamino)ethyl]-5-isoquinolinesulphonamide (H-89). 6. Forskolin, an
activator of endogenous adenylate cyclase, and 3-isobutyl-1-methylxanthine, a
phosphodiesterase inhibitor, mimicked the ability of noradrenaline to increase
both steady-state pHi and rates of pHi recovery from imposed acid loads, as did
Sp-cAMPS, a selective activator of cAMP-dependent protein kinase. The effect of
forskolin on steady-state pHi was blocked by pre-treatment with Rp-cAMPS whereas
the effect of Sp-cAMPS was enhanced by pre-treatment with the protein phosphatase
inhibitor, okadaic acid. 7. Noradrenaline also increased steady-state pHi and
rates of pHi recovery from imposed acid loads in cultured postnatal rat
hippocampal neurones. In this preparation, the effects of noradrenaline were
occluded by 18-24 h pre-treatment with cholera toxin. 8. We conclude that
noradrenaline increases the activity of the Na+-H+ exchanger in rat hippocampal
neurones, probably by inducing an alkaline shift in the pHi dependence of the
antiport, thereby raising steady-state pHi. The effects of noradrenaline are
mediated by beta-adrenoceptors via a pathway which involves the alpha-subunit of
the stimulatory G-protein Gs (Gsalpha), adenylate cyclase, cAMP and the
subsequent activation of cAMP-dependent protein kinase which, in turn, may
phosphorylate the exchange mechanism.
PMID- 9763639
TI - New observations on coupling between group II muscle afferents and feline gamma
motoneurones.
AB - 1. Extra- or intracellular recordings were made from seventy-six gamma
motoneurones of hindlimb muscles in chloralose anaesthetized cats to re-assess
the coupling between secondary muscle spindle afferents (group II muscle
afferents) and these neurones. The latencies of a number of responses evoked by
group II muscle afferents in gamma-motoneurones were shorter than minimal
latencies of responses induced disynaptically in other spinal neurones. These
latencies are therefore compatible with monosynaptic coupling between muscle
spindle secondaries and gamma-motoneurones. 2. Responses fulfilling criteria for
monosynaptically evoked responses were seen in about one third of gamma
motoneurones with input from the group II muscle afferents tested (in 6 of 18
motoneurones recorded intracellularly and in 26 of 74 motoneurones recorded
extracellularly). They were usually evoked from only one of the stimulated
nerves, stimulation of group II afferents of other nerves being followed by
responses at longer latencies. 3. Most gamma-motoneurones were excited by group
II afferents from several muscles, both flexors and extensors. However, a
comparison of group II input to gamma-motoneurones innervating medial
gastrocnemius and four other hindlimb muscles revealed differences in both
incidence and sources. 4. This study extends results of previous studies by
providing evidence that some synaptic actions of group II afferents, including
afferents from the same muscle, are evoked monosynaptically, and may assist in
sustaining the activation of gamma-motoneurones by positive feedback.
PMID- 9763640
TI - Modulation of responses of feline gamma-motoneurones by noradrenaline, tizanidine
and clonidine.
AB - 1. Effects of noradrenaline (NA) and the alpha2 agonists tizanidine and clonidine
were tested on extracellularly recorded responses of gamma-motoneurones in deeply
anaesthetized cats. Two types of responses were used; firstly, short latency
phasic responses evoked by electrical stimulation of group II afferents in a
muscle nerve and, secondly, tonic background discharges. 2. Responses evoked by
group II muscle afferents were depressed when NA and tizanidine were applied
ionophoretically close to a gamma-motoneurone and when clonidine was applied
systemically. The number of spike potentials evoked by stimulation of these
afferents decreased and their latencies increased. Responses evoked by flexor or
extensor afferents in gamma-motoneurones innervating flexors or extensors were
similarly depressed. 3. Tonic discharges were inconsistently and/or
insignificantly affected by locally applied NA and tizanidine but were depressed
by systemically applied clonidine. 4. Control tests indicate specific effects of
NA and tizanidine application since similarly ionophoresed H+ ions did not change
responses of gamma-motoneurones to stimulation of group II afferents, or only
weakly enhanced their background discharges. Furthermore, serotonin ejected from
a solution with a similar pH facilitated rather than depressed responses of gamma
motoneurones. 5. The results indicate that some antispastic effects of clonidine
and tizanidine may be due to the depression of group II-evoked responses of gamma
motoneurones, resulting in weaker responses of muscle spindles to muscle
stretches.
PMID- 9763641
TI - Reappearance of activity in the vestibular neurones of labyrinthectomized guinea
pigs is not delayed by cycloheximide.
AB - 1. In mammals, unilateral labyrinthectomy induces an immediate depression of the
resting discharges in the neurones of the ipsilateral vestibular nuclei. Later
on, a spontaneous restoration of this activity occurs. The aim of the present
study was to test the possibility that protein synthesis could be involved in the
start of this process in the guinea-pig. 2. Cycloheximide (CHX), a protein
synthesis inhibitor, was injected intramuscularly 1 h before (30 mg kg-1) and 5 h
after (15 mg kg-1) labyrinthectomy. 3. In a first group of animals, CHX was found
to induce an inhibition of protein synthesis at levels ranging from 71 to 93% for
9 h after labyrinthectomy. 4. In a second group of alert animals, we studied
single unit activity of second-order vestibular neurones. It was found that, in
the 12-16 h post-labyrinthectomy period, at a time when restoration began in
guinea-pigs not treated with CHX, the discharges in the labyrinthectomized group
treated with CHX were not different from those observed in a previous study in
labyrinthectomized animals not treated with CHX. 5. We conclude that protein
synthesis is not required for the start of restoration of activity in the
vestibular neurones deprived of their ipsilateral labyrinthine input.
PMID- 9763642
TI - Premature bifurcation of the apical dendritic trunk of vibrissa-responding
pyramidal neurones of X-irradiated rat neocortex.
AB - 1. Electrophysiological and morphological experiments were performed on the
pyramidal neurones of the somatosensory neocortex of the adult rat that had been
exposed in utero to 200 rad of X-irradiation. Under urethane anaesthesia, evoked
gross potentials, extracellular and intracellular neuronal responses, and laminar
field potentials were recorded. The evoked epicortical potential to deflection of
a single whisker was a long-lasting positive wave which contrasted with a
biphasic positive-negative complex in unirradiated controls. Neurones were
initially tested during extracellular recording for responses to whisker
deflections. This was followed by intracellular injection with horseradish
peroxidase (HRP), and the HRP-stained neuronal elements were visualized using
diaminobenzidine as a chromagen. 2. Fifty neurones were recorded and stained
through the soma. The mean response latency was 15.1 ms. Of these, thirty-six
showed premature bifurcation of the apical dendrite. The angle of bifurcation of
the apical dendrite was measured in the coronal plane and was found to be a
function of the depth at which the soma was located and the distance between the
soma and bifurcation point. It was suggested that the apical dendrites of these
neurones underwent premature bifurcation due to an imbalance between the growth
of neurones and skull. 3. Fifteen neurones were recorded and stained through the
presumed apical dendritic shaft. The mean response latency was 19.5 ms. The
electrode track left in the histological specimen pointed to the stained apical
dendrite. Dendritic elements distal to the entry point were preferentially filled
with HRP. In no cases were somata stained. There was, in turn, no evidence of
recording from dendritic elements distal to the bifurcation since no electrode
track was found to point to these elements. That dendritic spike responses may
not travel beyond the bifurcation was further substantiated by laminar analysis
of field potentials.
PMID- 9763643
TI - Modification of activity-dependent increases of cerebral blood flow by excitatory
synaptic activity and spikes in rat cerebellar cortex.
AB - 1. Mechanisms of activity-dependent increases in cerebral blood flow (CBF) were
examined in rat cerebellar cortex using the laser Doppler flow technique and
extracellular recordings of single unit activity and field potentials. 2.
Stimulation of the monosynaptic climbing fibre system evoked long-lasting complex
spikes in Purkinje cells, and extracellular field potentials with a
characteristic profile that indicated contributions from both passive and active
membrane mechanisms. The concomitant CBF increases were reproducible at fairly
short intervals, and suggest that both synaptic activity and spikes may
contribute to increased CBF. 3. Stimulation of the disynaptic parallel fibre
system inhibited the spiking activity in Purkinje cells, while the postsynaptic
activity increased as indicated by the simultaneously recorded field potential.
Nevertheless, CBF always increased. The inhibition of spike firing activity was
partly dependent on GABAergic transmission, but may also relate to the intrinsic
membrane properties of Purkinje cells. 4. The CBF increases evoked by parallel or
climbing fibre stimulation were highly correlated to the sum of neural
activities, i.e. the negativity of field potentials multiplied by the stimulus
frequency. This suggests a robust link between extracellular current flow and
activity-dependent increases in CBF. 5. AMPA receptor blockade attenuated CBF
increases and field potential amplitudes, while NMDA receptor antagonism did not.
This is consistent with the idea that the CBF responses are of neuronal origin.
6. This study has shown that activity-dependent CBF increases evoked by
stimulation of cerebellar parallel fibres are dependent on synaptic excitation,
including excitation of inhibitory interneurones, whereas the net activity of
Purkinje cells, the principal neurones of the cerebellar cortex, is unimportant
for the vascular response. For the climbing fibre system, not only synaptic
activity but also the generation of complex spikes from Purkinje cells contribute
to the increases in CBF. The strong correlation between CBF and field potential
amplitudes suggests that extracellular ion fluxes contribute to the coupling of
brain activity to blood flow.
PMID- 9763644
TI - The influence of nerves on the secretion of immunoglobulin A into submandibular
saliva in rats.
AB - 1. The influence of sympathetic and parasympathetic nerve stimulations on
salivary secretion of immunoglobulin A (IgA) was studied in the submandibular
glands of anaesthetized rats by stimulating the nerve supplies with bipolar
electrodes. 2. Although the flow of saliva from sympathetically stimulated glands
was only 23% of that from parasympathetically stimulated glands the output of IgA
was over 2-fold greater. This difference was attributable to influences of the
nerves on IgA secretion through the epithelial cell polymeric immunoglobulin
receptor-mediated pathway, as Western blotting with specific antibodies to IgA
and secretory component revealed that secretory IgA (SIgA) dominated in all
saliva samples. 3. Study of saliva secreted in sequential periods of nerve
stimulation or following rest pauses suggested that SIgA secretion occurred in
the absence of stimulation but this was upregulated 2.6- and 6-fold by
parasympathetic and sympathetic nerve stimulations, respectively, compared with
the calculated unstimulated rate. 4. The IgA content of extensively stimulated
glands was 77% of levels in unstimulated contralateral control glands despite a
secretion into saliva equivalent to almost 90% of the glandular IgA content. The
IgA may be synthesized and secreted by glandular plasma cells at a rate which
exceeds demand and/or such synthesis may be upregulated by nerve impulses. 5. The
results indicate that salivary secretion of SIgA is upregulated by nerve impulses
and that sympathetic nerves induce a greater effect than parasympathetic nerves.
PMID- 9763645
TI - Necessity of acetylcholine for retinal directionally selective responses to
drifting gratings in rabbit.
AB - 1. A model for retinal directional selectivity postulates that GABAergic
inhibition of responses to motions in the null (anti-preferred) direction
underlies this selectivity. An alternative model postulates that besides this
inhibition, there exists an asymmetric, nicotinic acetylcholine (ACh) input from
starburst amacrine cells. It is possible for the latter but not the former model
that stimuli could exist such that nicotinic blockade eliminates directional
selectivity. Such stimuli would drive the cholinergic but not the GABAergic
system well. 2. So far, attempts to eliminate directional selectivity with
nicotinic blockade have failed, but they always used isolated, moving bars as the
stimulus. We confirmed this failure for On-Off directionally selective (DS)
ganglion cells in our preparation of the rabbit's retina. 3. However, while
recording from these cells, we discovered that nicotinic blockade eliminated
directional selectivity to drifting, low spatial frequency sine- and square-wave
gratings. 4. This effect was not just due to the smallness of the responses under
nicotinic blockade. NMDA blockade caused even smaller responses, but no loss of
directional selectivity. 5. This result is consistent with a two-asymmetric
pathways model of directional selectivity, but inconsistent with an asymmetric
GABA-only model. 6. We conclude that asymmetric nicotinic inputs extend the range
of stimuli that can elicit directional selectivity to include moving textures,
that is, those with multiple peaks in their spatial luminance profile.
PMID- 9763646
TI - Buffering of blood pressure variability by the renin-angiotensin system in the
conscious dog.
AB - 1. The renin-angiotensin system (RAS) participates in the compensation of major
blood pressure disturbances such as haemorrhage and is involved in the tonic long
term (> 1 day) maintenance of mean arterial blood pressure (MABP). Since its
contribution to the short-term (< 1 h) buffering of normal blood pressure
variability is not known, this was investigated in resting conscious dogs. 2. The
regulatory efficiency and the response time of the RAS were studied by an acute
step reduction of renal artery pressure to 70 mmHg for 1 h using a suprarenal
aortic cuff. After a delay of at least 100 s, MABP rose exponentially by 22 +/- 5
mmHg in normal dogs (n = 4), by 6 +/- 3 mmHg after angiotensin converting enzyme
(ACE) inhibition (n = 4), and by 25 +/- 5 mmHg after ganglionic blockade (n = 4).
MABP returned to control after release of the cuff with similar time courses. The
time constants of the MABP responses were in the range of 20 min. Thus, possible
feedback oscillations of the RAS would be expected around 0.0025 Hz (1/(4 x 100
s)); a buffering effect would be possible below this frequency. 3. Blood pressure
variability was investigated by spectral analysis of MABP from 3.75 h recordings
in the frequency ranges of 0.002-0.003 Hz (feedback oscillations) and below 0.002
Hz (buffering effect). 4. ACE inhibition (n = 7) decreased MABP by 11 +/- 2 mmHg
(P < 0.05), but in both frequency ranges integrated spectral density was not
affected. ACE inhibition also failed to significantly change spectral density in
either of the two frequency ranges under the following conditions: (1) during
ganglionic blockade (n = 7), (2) during a low-sodium diet (except for a very
slight elevation below 0.002 Hz) (n = 7), and (3) when the fall of MABP induced
by ACE inhibition was compensated by an angiotensin II infusion (n = 7). 5. It is
concluded that in spite of its high regulatory efficiency with an adequate
response time the RAS does not directly contribute to the short-term buffering of
blood pressure variability, nor does it give rise to feedback oscillations under
normal resting conditions. Even if the RAS is stimulated by sodium restriction
its contribution to short-term blood pressure buffering is only marginal.
PMID- 9763648
TI - In vivo measurements of the triceps surae complex architecture in man:
implications for muscle function.
AB - 1. The objectives of this study were to (1) quantify experimentally in vivo
changes in pennation angle, fibre length and muscle thickness in the triceps
surae complex in man in response to changes in ankle position and isometric
plantarflexion moment and (2) compare changes in the above muscle architectural
characteristics occurring in the transition from rest to a given isometric
plantarflexion intensity with the estimations of a planimetric muscle model
assuming constant thickness and straight muscle fibres. 2. The gastrocnemius
medialis (GM), gastrocnemius lateralis (GL) and soleus (SOL) muscles of six males
were scanned with ultrasonography at different sites along and across the muscle
belly at rest and during maximum voluntary contraction (MVC) trials at ankle
angles of -15 deg (dorsiflexed direction), 0 deg (neutral position), +15 deg
(plantarflexed direction) and +30 deg. Additional images were taken at 80, 60, 40
and 20% of MVC at an ankle angle of 0 deg. 3. In all three muscles and all
scanned sites, as ankle angle increased from -15 to +30 deg, pennation increased
(by 6-12 deg, 39-67%, P < 0.01 at rest and 9-16 deg, 29-43%, P < 0.01 during MVC)
and fibre length decreased (by 15-28 mm, 32-34%, P < 0.01 at rest and 8-10 mm, 27
30%, P < 0.05 during MVC). Thickness in GL and SOL increased during MVC compared
with rest (by 5-7 mm, 36-47%, P < 0.01 in GL and 6-7 mm, 38-47%, P < 0.01 in SOL)
while thickness of GM did not differ (P > 0.05) between rest and MVC. 4. At any
given ankle angle the model underestimated changes in GL and SOL occurring in the
transition from rest to MVC in pennation angle (by 9-12 deg, 24-38%, P < 0.01 in
GL and 9-14 deg, 25-28%, P < 0.01 in SOL) and fibre length (by 6-15 mm, 22-39%, P
< 0.01 in GL and 6-8 mm, 23-24%, P < 0.01 in SOL). 5. The findings of the study
indicate that the mechanical output of muscle as estimated by the model used may
be unrealistic due to errors in estimating the changes in muscle architecture
during contraction compared with rest.
PMID- 9763647
TI - Voluntary activation of human elbow flexor muscles during maximal concentric
contractions.
AB - 1. To measure voluntary activation of human elbow flexor muscles during maximal
concentric contractions, the twitch interpolation method was modified to enable
detection of torque increments evoked by single stimuli during contractions of up
to 300 deg s-1. Subjects flexed the elbow to rotate a loaded beam 'as fast as
possible' (load typically 23-58 N m) from 70 deg below to 70 deg above the
horizontal. Electrical stimuli were delivered to biceps brachii when the beam
passed through the horizontal. Voluntary activation was estimated from the
amplitude of the interpolated twitch, which was expressed as a percentage of the
twitch produced by relaxed muscles shortening at the same velocity. 2. In eleven
subjects, the level of voluntary activation during repeated maximal concentric
contractions (median 99.4%) did not differ significantly from that during maximal
isometric contractions (98.0%). Voluntary activation during maximal contractions
did not depend on shortening velocity and was the same when tested at two angles
30 deg apart. 3. To induce fatigue, five subjects repeatedly lifted and lowered a
heavy load at about 30 deg s-1, and continued for ten to twelve contractions
after they needed assistance to continue lifting. All maintained the capacity to
attain maximal levels of activation. 4. It is concluded that voluntary drive to
elbow flexor muscles during maximal concentric contractions is usually maximal or
near-maximal, and that this level of drive can be maintained during development
of peripheral fatigue.
PMID- 9763649
TI - Damage to human muscle from eccentric exercise after training with concentric
exercise.
AB - 1. It is known that a period of eccentric exercise provides protection against
damage to muscle from subsequent eccentric exercise. Here we ask, does concentric
exercise do the opposite, make muscle more prone to damage? 2. The triceps surae
muscle group of one leg in each of eight human subjects was subjected to 30 min
of concentric exercise per day, for 5 days. At the end of the training period
there was a small but significant increase in passive torque in the exercised
muscle (P < 0.05), with no changes in the untrained muscle. 3. After a single
period of eccentric exercise, angle-torque curves for muscles of both legs
shifted in the direction of longer muscle lengths, suggestive of an increase in
series compliance. The shift in the concentrically trained muscle was
significantly greater over the first 48 h post-exercise (P < 0. 05). 4. The
volume of the trained leg increased significantly more than the untrained leg for
five subjects over 72 h post-exercise (P < 0.05). Peak torque fell, passive
stiffness increased and both muscles became sore, but with no significant
differences between the two legs. 5. It is concluded that a period of concentric
exercise increases the susceptibility of muscle to changes associated with the
damage from eccentric exercise.
PMID- 9763650
TI - Habituation of the initial responses to cold water immersion in humans: a central
or peripheral mechanism?
AB - 1. The initial respiratory and cardiac responses to cold water immersion are
thought to be responsible for a significant number of open water deaths each
year. Previous research has demonstrated that the magnitude of these responses
can be reduced by repeated immersions in cold waterwhether the site of
habituation is central or peripheral. 2. Two groups of subjects undertook two 3
min head-out immersions in stirred water at 10 C of the right-hand side of the
body (R). Between these two immersions (3 whole days) the control group (n = 7)
were not exposed to cold water, but the habituation group (n = 8) undertook a
further six 3 min head-out immersions in stirred water at 10 C of the left-hand
side of the body (L). 3. Repeated L immersions reduced (P < 0.01) the heart rate,
respiratory frequency and volume responses. During the second R immersion a
reduction (P < 0.05) in the magnitude of the responses evoked was seen in the
habituation group but not in the control group, despite both groups having
identical skin temperature profiles. 4. It is concluded that the mechanisms
involved in producing habituation of the initial responses are located more
centrally than the peripheral receptors.
PMID- 9763651
TI - Report of the seventh international workshop on human chromosome 21 mapping 1997.
PMID- 9763652
TI - The cytogenetic and molecular characterization of benign and malignant soft
tissue tumors.
AB - Cytogenetic analyses of benign and malignant soft tissue tumors have led to the
description of recurrent, specific, and even pathognomonic chromosomal
translocations and/or other rearrangements in most types of soft tissue tumors.
The consistent karyotypic rearrangements have provided critical diagnostic
information in this group of neoplasms that often presents significant diagnostic
challenges to the clinician and the pathologist. These findings have also been
instrumental in the characterization of the abnormalities at the molecular level.
Novel genes have been isolated from the translocation junctions and the
mechanisms of their deregulation identified. This has increased our understanding
of the histogenesis of these tumors, paved the way for the molecular diagnosis of
many sarcomas, aided in directing therapy, and also provided important prognostic
information.
PMID- 9763653
TI - Assignment of protein kinase C eta (Pkch) to mouse chromosome band 12C3-D2 by in
situ hybridization.
PMID- 9763654
TI - Assignment of IkappaB kinase beta (IKBKB) to human chromosome band 8p12-->p11 by
in situ hybridization.
PMID- 9763655
TI - Assignment of the human oxidized low-density lipoprotein receptor gene (OLR1) to
chromosome 12p13.1-->p12.3, and identification of a polymorphic CA-repeat marker
in the OLR1 gene.
PMID- 9763656
TI - Genomic organization of the bovine aromatase encoding gene and a homologous
pseudogene as revealed by DNA fiber FISH.
AB - In cattle, the CYP19 locus comprises the aromatase cytochrome P450-encoding gene
(CYP19) and a homologous pseudogene (CYP19P1). It has been assigned to chromosome
region 10q26. Cloning of genomic DNA revealed that the CYP19 gene covers more
than 56 kb. Its precise extent is still unknown because the DNA spanning the
untranslated first exon 1.1 and the coding region (exons 2 to 10) have not been
isolated. Furthermore, the chromosome arrangement of closely linked CYP19 and
CYP19P1 was also not clear. To establish a high resolution physical map of the
entire CYP19 locus, fluorescence in situ hybridization to extended bovine genomic
DNA fibers (fiber FISH) was performed. The results demonstrate (1) that the clone
containing exon 1.1 is located about 19 kb upstream from the CYP19 coding region.
(2) Within the chromosome region 10q26 CYP19 and CYP19P1 are arranged "tail-to
head", being separated by a distance of about 24 kb between the labeled clones.
(3) The physical size of the bovine CYP19 locus amounts to a minimum of 130 kb.
PMID- 9763657
TI - Cloning of TCFL5 encoding a novel human basic helix-loop-helix motif protein that
is specifically expressed in primary spermatocytes at the pachytene stage.
AB - We have isolated a novel human gene that is expressed specifically in primary
spermatocytes in the testis. The cDNA contains an open reading frame of 1356 bp,
encoding a 452-amino-acid protein that includes a basic Helix-Loop-Helix (bHLH)
motif. The gene, which was mapped to chromosome region 20q13.3-->qter by
fluorescence in situ hybridization, consists of six exons and spans approximately
24 kb of genomic DNA. Immunohistochemical staining located the gene product
exclusively in cell nuclei of primary spermatocytes at the pachytene stage, but
not in those at the leptonema stage. We named this gene TCFL5 (transcription
factor-like 5, basic helix-loop-helix). The cell-type and stage-specific
expression of TCFL5 indicates that this protein may function in a crucial role in
spermatogenesis as a transcription factor by regulating cell proliferation or
differentiation of cells through binding to a specific DNA sequence like other
bHLH molecules.
PMID- 9763658
TI - Linkage mapping of Lims1l, the murine homolog of the human LIM domain gene PINCH,
to mouse chromosome 10.
AB - The human LIM domain gene LIMS1 was used to identify a mouse homolog. The
resulting mouse sequence was used to identify a polymorphism by SSCP analysis.
Linkage studies performed in the EUCIB backcross placed Lims1l on the proximal
portion of mouse Chromosome 10. This localisation makes it an interesting
candidate for the deafness mutant, waltzer (v).
PMID- 9763659
TI - Hemizygous deletion of the HPC-1/syntaxin 1A gene (STX1A) in patients with
Williams syndrome.
AB - HPC-1/syntaxin 1A is a membrane protein that plays an important role in
exocytosis of neurotransmitters from neuronal cells. We previously mapped the
human HPC-1/syntaxin 1A gene (STX1A) to chromosome 7q11.2, which is within the
Williams syndrome (WS) region. Here, we performed FISH analysis on 46 patients
with WS to examine the relationship between STX1A and WS. Our results showed a
hemizygous deletion of the HPC-1/syntaxin 1A gene in each patient, suggesting
that the neurological symptoms of WS may be related to the hemizygous deletion of
STX1A.
PMID- 9763660
TI - Pathogenetics of 45,X/46,XY gonadal mosaicism.
AB - Five patients with 45,X/46,XY mosaicism ranging from 8% to 66% of 46, XY
lymphocytes in the peripheral blood were studied. Their age when chromosome
studies were performed ranged from a few days to 37 yr. The phenotypic
presentations were two females with gonadal dysgenesis and Turner syndrome
features (cases 1 and 2), two males with ambiguous genitalia and mixed gonadal
dysgenesis (cases 3 and 4), and an infertile male with an atrophic testis (case
5). Fluorescence in situ hybridization (FISH) using dual-color X and Y probes on
paraffin-embedded sections of the gonads was performed to assess mosaicism. A
mosaic cell line with a Y chromosome was present in the streak ovary, dysgenetic
gonad, and testis. In the mixed gonadal dysgenesis cases (cases 3 and 4), the
testis had a higher percentage (greater than two fold) of XY cells than the ovary
had. However, the highest ratio of cells with a Y chromosome was in the atrophic
testis of the infertile male (case 5). The distribution of mosaic clones in the
different gonadal cell types was examined. Both females (cases 1 and 2) with
dysgenetic gonads had scant ovarian stroma and nests of Leydig or hilus cells. In
FISH studies, the coelomic epithelial cells were predominantly 46,XY; in
comparison, the Leydig and hilus cells had a lower percentage and the ovarian
stroma the least number of cells with a Y signal. A mixed gonadal dysgenesis case
(case 3) possessed a right testis with an XY complement in approximately 21% of
Sertoli cells and approximately 14% of Leydig cells. The infertile male had an
atrophic testis with interstitial hyperplasia (case 5). His testis contained
Sertoli cells but no evidence of spermatogenesis. FISH detected a Y signal in
about 50-60% of the Sertoli and Leydig cells.
PMID- 9763661
TI - Position effect of translocations involving the inactive X chromosome: physical
linkage to XIC/XIST does not lead to long-range de novo inactivation in human
differentiated cells.
AB - Given the reported long-range cis-inactivating effect of the XIST gene in early
embryonic development and the lack of requirement of X-chromosome-specific
elements for propagating the inactive state, there exists the possibility of cis
inactivation of autosomal material after de novo translocation to an inactive X
chromosome (Xi) in differentiated cells. We have analyzed de novo radiation
induced translocations between the Xi and autosomes to study the maintenance and
spreading of X-chromosome inactivation (X inactivation) in relation to the
position of the X-inactivation center (XIC)/XIST in differentiated cells.
Autosome/Xi translocations were detected by fluorescence in situ hybridization
(FISH). The activation status of the chromosomes involved in the translocation
was determined by simultaneous immunocytogenetic studies using antibodies against
either BrdU incorporated at late S phase or acetylated histone H4. The position
of XIC/XIST in the reciprocal products of the translocation was determined by
XIST-specific FISH and computer enhancement. In other experiments, the Xq13
region carrying XIC/XIST was localized by computer enhancement of the DAPI
banding pattern. Our study in differentiated cells provides a visual
demonstration that physical separation from XIC/XIST does not result in
reactivation of inactive X-chromosome material and that X inactivation is not
spread to the translocated autosomes irrespective of the position of XIC/XIST.
This observation suggests that physical linkage to XIC/XIST does not lead to de
novo inactivation of autosomal material.
PMID- 9763662
TI - Genetic mapping of mouse centromere protein (Incenp and Cenpe) genes.
AB - Inner centromere protein (INCENP) and centromere protein E (CENPE) are two
functionally important proteins of the higher eukaryotic centromere. Using a
mouse Incenp genomic DNA and a mouse Cenpe cDNA to analyze recombinant inbred
mouse sets, as well as interspecific backcross panels, we have mapped these genes
to the proximal regions of mouse Chromosomes 19 and 6, respectively. Comparison
of Cenpe and human CENPE, which maps to chromosome region 4q24-->q25, has further
identified a new region of homology between the two species.
PMID- 9763663
TI - Localization of FCGR1 encoding Fcgamma receptor class I in primates: molecular
evidence for two pericentric inversions during the evolution of human chromosome
1.
AB - The human high-affinity receptor for immunoglobulin G, FcgammaRI (FCGR1), is
encoded by a family of three genes that share over 95% sequence homology.
Curiously, the three genes in this recently duplicated gene family flank the
centromere of human chromosome 1, with FCGR1B located at 1p12 and both FCGR1A and
FCGR1C located at 1q21. We have previously speculated that a pericentric
inversion could account for the separation of the genes in the FCGR1 family and
explain their current chromosomal location. Here we present evidence, obtained
through fluorescence in situ hybridization analysis, that in the rhesus monkey
(Macaca mulatta) and baboon (Papio papio) FCGR1 is located adjacent to the
centromere on the chromosomal arm with greatest homology to human 1p, whereas in
the chimpanzee (Pan troglodytes) it is located adjacent to the centromere on the
chromosomal arm with greatest homology to human 1q. The separation of the FCGR1
gene family in humans suggests that the location of a second pericentric
inversion, known to distinguish the human from the chimpanzee chromosome 1, is
within the FCGR1 gene family. This finding refines the assignment of homology
between the human and chimpanzee chromosomes 1.
PMID- 9763664
TI - Analysis of chromosome aberrations in a mammary carcinoma cell line from a dog by
using canine painting probes.
AB - A cell line derived from a spleen metastasis of a mammary carcinoma in a female
dog was analyzed by fluorescence in situ hybridization with canine chromosome
specific paints. The cell line showed a modal chromosome number of 77, with three
(90% of the cells) or four (10% of the cells) biarmed chromosomes. Aberrations
observed relate to chromosomes 8 or 11, 13 or 15, 37, 38, and X and include
chromosome loss (X), formation of isochromosomes (8 or 11, 13 or 15), and centric
fusion (37 and 38). In all aberrations, whole chromosomes are involved. None of
the genes known to be related to breast cancer development in humans and that has
mapped in the dog is located on one of the aberrant chromosomes. The results of
this study show that chromosome painting is a most useful tool for the analysis
of canine tumor cells.
PMID- 9763665
TI - A baboon (Papio hamadryas) with an isochromosome for the long arm of the X.
AB - A 5.5-yr-old female baboon was evaluated for sexual immaturity. She was small for
her age and had normal external female genitalia. However, she lacked cyclical
perineal turgescence and displayed atypical coloration of the perineal skin.
Laparoscopy revealed a small uterus and absence of both ovaries. Cytogenetic
analysis revealed a 42,X,i(X)(q10) karyotype. DNA analysis using loci DXS1683,
which maps to Xp22.1, and DXS297, which maps to Xq27.3, was consistent with
inheritance of the normal X chromosome from the dam and formation of the
isochromosome Xq from the paternal X.
PMID- 9763666
TI - Baboon/human homologies examined by spectral karyotyping (SKY): a visual
comparison.
AB - Baboon (Papio hamadryas) metaphase chromosomes were analyzed using spectral
karyotyping (SKY), a technique combining fluorescence microscopy, CCD-imaging,
and Fourier spectroscopy. Results from a comparison of SKY analyses using probes
derived from human chromosomes on baboon metaphases were consistent with the
majority of comparative gene mapping data between the two species. These data
were also compatible with earlier studies comparing macaque and human
chromosomes. Human (HSA) chromosome 2 was homologous to baboon (PHA) chromosomes
12 (HSA 2q) and 13 (HSA 2p), whereas three baboon chromosomes corresponded to two
different human chromosomes: PHA 3 to HSA 7 and HSA 21, PHA 7 to HSA 14 and HSA
15, and PHA 10 to HSA 20 and HSA 22. These results support the retained synteny
between the Hominidae and Cercopithecidae genomes.
PMID- 9763667
TI - Structure and chromosome mapping of the human small maf-genes MAFG and MAFK.
AB - The newly emerged Maf family proteins possess a highly conserved basic leucine
zipper (bZip) domain in common and are subdivided into large and small Maf
proteins. The Maf family proteins appear to regulate cell differentiation
processes and also cellular functions as partner molecules of CNC family
proteins. To facilitate understanding of the function of small Maf proteins, we
isolated the genes (MAFG and MAFK) encoding human small Maf proteins MafG and
MafK and characterized their structures and organization by means of restriction
enzyme mapping, Southern blot hybridization and nucleotide sequence analysis.
Organization of the small maf genes are highly conserved in vertebrates,
suggesting an important functional contribution of the gene products. We also
examined the location of these genes within the human genome by fluorescence in
situ hybridization (FISH) analysis. Human MAFG and MAFK are located at 17q25 and
7p22, respectively. Thus, small maf genes are not clustered in a single locus.
PMID- 9763668
TI - Assignment of CASP8 to human chromosome band 2q33-->q34 and Casp8 to the murine
syntenic region on chromosome 1B-proximal C by in situ hybridization.
PMID- 9763669
TI - Assignment of the melanocortin 4 receptor (MC4R) gene to human chromosome band
18q22 by in situ hybridisation and radiation hybrid mapping.
PMID- 9763670
TI - Assignment of the E1A-regulated transcription factor E4F gene (E4F1) to human
chromosome band 16p13.3 by in situ hybridization and somatic cell hybrids.
PMID- 9763671
TI - Genomic structure of a novel human gene (XYLB) on chromosome 3p22-->p21.3
encoding a xylulokinase-like protein.
AB - We isolated a novel human cDNA of 1963 nucleotides that included an open reading
frame encoding a protein of 528 amino acids. Homology analysis indicated that the
predicted gene product, XYLB, bore 22% identity to the xylulokinase of
Haemophilus influenzae that plays an important role in energy metabolism. The
gene consists of 18 exons and spans about 28 kb of genomic DNA on chromosome
3p21.3.
PMID- 9763673
TI - Fine mapping of 12 previously unassigned EST clones to individual YACs in the
familial Alzheimer's disease (FAD) region of chromosome 14q24.3.
AB - We have constructed an approximately 4-Mb YAC contig spanning the microsatellite
markers D14S1028-D14S61 on chromosome 14q24.3 using oligonucleotide primers to
microsatellite markers, ESTs and the genes PSEN1, FOS, TGFB3 and UBE2L1. This
contig consists of 44 ICI YACs and 5 megaCEPH YACs. The data reported here should
aid the final construction of an integrated map of chromosome 14 and allow the
identification and accurate mapping of additional novel ESTs within this region.
PMID- 9763672
TI - Assignment of the IkappaB-beta gene NFKBIB to human chromosome band 19q13.1 by in
situ hybridization.
PMID- 9763674
TI - Assignment of the horse progesterone receptor (PGR) and estrogen receptor (ESR1)
genes to horse chromosomes 7 and 31, respectively, by in situ hybridization.
PMID- 9763675
TI - Assignment of the horse mitochondrial glutamate oxaloacetate transaminase 2
(GOT2) and v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) to
horse chromosome 3 by in situ hybridization.
PMID- 9763676
TI - Mapping of the NDUFA2, NDUFA6, NDUFA7, NDUFB8, and NDUFS8 electron transport
chain genes by intron based radiation hybrid mapping.
PMID- 9763677
TI - Intron based radiation hybrid mapping of 15 complex I genes of the human electron
transport chain.
AB - At least 34 complex I subunits of the electron transport chain are encoded by the
nuclear genome, but only 14 of these have been mapped in the human. To rapidly
map additional subunits, we have performed a combination of database mining and
direct "wet" experimentation to identify intron and/or 5' upstream genomic DNA
regions for 16 complex I genes. Wet experimentation was applied to 5 genes, and
involved direct PCR amplification of introns by inter-exon PCR or splinkerette
based PCR walking. Database mining was applied to 11 genes, and entailed the
identification of incompletely spliced mRNAs and genomic CpG island clone
sequences. This data was in files that carried no documentary description of the
non-exon regions. Non-exon sequences were thus derived for 15 complex I genes and
used to design functional gene specific PCR assays. Radiation hybrid mapping of
these PCRs located 15 complex I genes to chromosomes l, 4, 5 (2 genes), 7 (2
genes), 8, 9 (2 genes), 11, 14, 16 (2 genes), 18, and 19.
PMID- 9763678
TI - Assignment of candidate DNA methyltransferase gene (DNMT2) to human chromosome
band 10p15.1 by in situ hybridization.
PMID- 9763679
TI - Assignment of FRA1H common fragile site to human chromosome band 1q42.1 proximal
to the nuclear NAD+ ADP-ribosyltransferase gene (ADPRT) and to the main 5S rRNA
gene locus.
PMID- 9763680
TI - Chromosomal localization of the human cytoplasmic dynein heavy chain gene DNCH2
to 11q21-->q22.1.
PMID- 9763681
TI - Autosomal-dominant, prelingual, nonprogressive sensorineural hearing loss:
localization of the gene (DFNA8) to chromosome 11q by linkage in an Austrian
family.
AB - A four-generation family suffering from an autosomal-dominant, congenital,
nonprogressive, nonsyndromic hearing loss was found in a rural region of Austria.
The hearing loss was moderate to severe, a pure tone audiogram showing a U-shaped
form with maximum loss at 2, 000 Hz. An initial genome search led to a lod score
of 3.01 with markers on chromosome 15. This locus was registered as DFNA8 in the
HUGO data base. Further sampling of the family, however, yielded data that
reduced the maximal lod score with chromosome 15 markers to 1.81. The genome
search was restarted using an ABITM genotyper, which eventually detected several
positive two-point lod scores with markers from the long arm of chromosome 11.
The highest value was 3. 6, which was seen with the marker D11S934. Haplotype
analysis excluded the gene from the chromosomal region proximal from D11S898 and
distal to D11S1309. These results place the gene in the region of the hearing
loss gene DFNA12. Recent evidence suggests that the somewhat different phenotypes
found in these two families are due to two different mutations in the human alpha
tectorine gene (Verhoeven et al., 1998).
PMID- 9763682
TI - Abstracts of the 35th american cytogenetics conference
PMID- 9763683
TI - Xanthan gum biosynthesis and application: a biochemical/genetic perspective.
AB - Xanthan gum is a complex exopolysaccharide produced by the plant-pathogenic
bacterium Xanthomonas campestris pv. campestris. It consists of D-glucosyl, D
mannosyl, and D-glucuronyl acid residues in a molar ratio of 2:2:1 and variable
proportions of O-acetyl and pyruvyl residues. Because of its physical properties,
it is widely used as a thickener or viscosifier in both food and non-food
industries. Xanthan gum is also used as a stabilizer for a wide variety of
suspensions, emulsions, and foams. This article outlines aspects of the
biochemical assembly and genetic loci involved in its biosynthesis, including the
synthesis of the sugar nucleotide substrates, the building and decoration of the
pentasaccharide subunit, and the polymerization and secretion of the polymer. An
overview of the applications and industrial production of xanthan is also
covered.
PMID- 9763688
TI - Bacterial complementation as a means to test enzyme-ligand interactions.
AB - A bacterial complementation assay has been developed for the rapid screening of a
large number of compounds to identify those that inhibit an enzyme target for
structure-based inhibitor design. The target enzyme is the hypoxanthine
phosphoribosyltransferase (HPRT). This enzyme has been proposed as a potential
target for inhibitors that may be developed into drugs for the treatment of
diseases caused by several parasites. The screening assay utilizes genetically
deficient bacteria complemented by active, recombinant enzyme grown in selective
medium in microtiter plates. By comparing absorbance measurements of bacteria
grown in the presence and absence of test compounds, the effect of the compounds
on bacterial growth can be rapidly assayed. IC50 values for inhibition of
bacterial growth are a reflection of the ability of the compounds to bind and/or
inhibit the recombinant enzyme. We have tested this bacterial complementation
screening assay using recombinant HPRT from the parasites. Plasmodium falciparum
and Trypanosoma cruzi, as well as the human enzyme. The results of these studies
demonstrate that a screening assay using bacterial complement selection can be
used to identify compounds that target enzymes and can become an important part
of structure-based drug design efforts.
PMID- 9763687
TI - Characterization of a novel Streptococcus thermophilus rolling-circle plasmid
used for vector construction.
AB - The complete nucleotide sequence of pER371, a native plasmid in Streptococcus
thermophilus ST137, was determined. A putative open reading frame coding for a
replication protein, Rep371, was identified. A characteristic promoter sequence
and ribosome-binding site were found upstream of rep371. Rep371 (247 amino acid
residues) does not show homology with RepA and RepS of the small S. thermophilus
cryptic plasmids pST1-No.29 and pST1 respectively. The plus-origin sequence and
Rep371 are highly homologous to the corresponding elements of the Staphylococcus
aureus plasmids pC194 and pSK89. A novel 140-nucleotide palindromic minusorigin
sequence, which is structurally similar but does not show sequence homology to
the palA region of pC194, was identified in pER371. A palindromic sequence
capable of forming a putative hairpin structure was identified and subsequently
recognized as being highly conserved among several lactococcal rolling-circle
plasmids. Cloning vectors derived from pER371 should provide valuable gene
delivery vehicles for the genetic engineering of lactic acid bacteria.
PMID- 9763689
TI - Efficient production of intact human parathyroid hormone in a Saccharomyces
cerevisiae mutant deficient in yeast aspartic protease 3 (YAP3).
AB - When human parathyroid hormone (hPTH) is expressed as a secretory product in
yeast, the main problem is the aberrant proteolytic cleavage that reduces the
yield of intact protein. To overcome this problem, we developed an hPTH
expression system using a host strain in which the YAP3 gene encoding yeast
aspartic protease 3 (YAP3) was disrupted. After 48 h of culture, most of the hPTH
secreted by the yap3 disruptant remained intact, whereas more than 90% of the
hPTH secreted by the wild-type strain was cleaved. When the authentic hPTH was
incubated in each of the culture supernatants of untransformed yap3 disruptant
and wild-type strain, the proteolysis proceeded much more slowly in the culture
supernatant of yap3 disruptant than in that of the wild type. The extent of hPTH
proteolysis was also significantly reduced by the addition of pepstatin A, a
specific aspartic protease inhibitor. The results suggest that YAP3 is involved
in the internal cleavage of hPTH expressed in yeast. The correct processing of
the intact hPTH secreted in the yap3 disruptant demonstrates that the yeast
mutant lacking the YAP3 activity is a suitable host for the high-level expression
of intact hPTH.
PMID- 9763691
TI - Composition of the cell walls of several yeast species.
AB - Cell walls, representing 26%-32% of the cell dry weight, were prepared from
several strains of the yeasts Kloeckera apiculata, Debaryomyces hansenii,
Zygosaccharomyces bailii, Kluyveromyces marxianus and Saccharomyces cerevisiae.
Extraction of the walls with potassium hydroxide at 4 degrees C, followed by
saturation of the alkali-soluble extract with ammonium sulphate gave fractions of
mannoprotein, alkali-soluble glucan and alkali-insoluble glucan. Chitin was
associated with the alkali-insoluble glucan. The proportions of the different
fractions within the walls varied with the species and strain. Mannoprotein
comprised between 25% and 34% of the walls, the content of alkali-insoluble
glucan ranged from 15% to 48%, and the content of alkali-soluble glucan ranged
from 10% to 48%. There was significant variation in the physical appearance of
the alkali-soluble glucans and the relative viscosity of suspensions of these
glucans. The yeasts could represent novel sources of polysaccharides with
industrial and medical applications.
PMID- 9763690
TI - Production of trehalose synthase from a basidiomycete, Grifola frondosa, in
Escherichia coli.
AB - The genomic DNA and cDNA for a gene encoding a novel trehalose synthase (TSase)
catalyzing trehalose synthesis from alpha-D-glucose 1-phosphate and D-glucose
were cloned from a basidiomycete, Grifola frondosa. Nucleotide sequencing showed
that the 732-amino-acid TSase-encoding region was separated by eight introns.
Consistent with the novelty of TSase, there were no homologous proteins
registered in the data-bases. Recombinant TSase with a histidine tag at the NH2
terminal end, produced in Escherichia coli, showed enzyme activity similar to
that purified from the original G. frondosa strain. Incubation of alpha-D-glucose
1-phosphate and D-glucose in the presence of recombinant TSase generated
trehalose, in agreement with the enzymatic property of TSase that the equilibrium
lay far in the direction of trehalose synthesis.
PMID- 9763692
TI - The colonization of a simulator of the human intestinal microbial ecosystem by a
probiotic strain fed on a fermented oat bran product: effects on the
gastrointestinal microbiota.
AB - The effects of Lactobacillus-GG-fermented oat bran product on the microbiota and
its metabolic activity in the human gut were investigated, using a simulator of
the human intestinal microbial ecosystem (SHIME), by analysing the bacterial
population, shortchain fatty acids and gas production. In addition, the effects
of fermented oat bran supernatant and supernatant samples from reactors 4, 5 and
6 (large intestine) on the growth of Escherichia coli IHE 13047, Enterococcus
faecalis VTT E-93203, Lactobacillus rhamnosus VTT E-94522 (Lactobacillus GG) and
Lactococcus lactis subsp. lactis VTT E-90414 were monitored to ascertain possible
stimulatory/inhibitory effects by an in vitro turbidometric method. Our
experiments showed that Lactobacillus GG colonized the SHIME reactor and this
colonization could be maintained for several weeks without extra supplementation.
Oat bran feeding also favoured the growth of bifidobacteria and caused an
increase in the production of acetic, propionic and butyric acid as well as CH4
and CO2. However, the effects of oat bran, either on bacterial populations or on
their metabolic activity, were not directly dose-dependent. In turbidometric
measurements, the supernatant of fermented oat bran exerted an inhibitory effect
of Lactobacillus GG, but stimulated the growth of enterococci.
PMID- 9763694
TI - Detection of ferulic acid esterase production by Bacillus spp. and lactobacilli.
AB - The production of feruloyl esterase activity by Bacillus spp. and lactobacilli
can be detected in an agarplate assay. The assay involves the substitution of the
main carbon source in specific agar with ethyl ferulate. A number of Bacillus
spp., predominantly B. subtilis strains, were found to exhibit feruloyl esterase
activity by this method. Of the examined lactobacilli, Lb. fermentum (NCFB 1751)
showed the highest level of ferulic acid esterase activity. The enzyme was
released from harvested cells by sonication and showed pH and temperature optima
of 6.5 and 30 degrees C respectively.
PMID- 9763693
TI - Antimould activity of sourdough lactic acid bacteria: identification of a mixture
of organic acids produced by Lactobacillus sanfrancisco CB1.
AB - Sourdough lactic acid bacteria, cultivated in wheat flour hydrolysate, produced
antimould compounds. The antimould activity varied greatly among the strains and
was mainly detected within obligately heterofermentative Lactobacillus spp. Among
these, Lb. sanfrancisco CB1 had the largest spectrum. It inhibited moulds related
to bread spoilage such as Fusarium, Penicillium, Aspergillus and Monilia. A
mixture of acetic, caproic, formic, propionic, butyric and n-valeric acids,
acting in a synergistic way, was responsible for the antimould activity. Caproic
acid played a key role in inhibiting mould growth.
PMID- 9763695
TI - The use of Escherichia coli bearing a phoN gene for the removal of uranium and
nickel from aqueous flows.
AB - A Citrobacter sp. originally isolated from metal-polluted soil accumulates heavy
metals via metalphosphate deposition utilizing inorganic phosphate liberated via
PhoN phosphatase activity. Further strain development was limited by the non
transformability of this environmental isolate. Recombinant Escherichia coli DH5
alpha bearing cloned phoN or the related phoC acquired metal-accumulating
ability, which was compared with that of the Citrobacter sp. with respect to
removal of uranyl ion (UO2(2+)) from dilute aqueous flows and its deposition in
the form of polycrystalline hydrogen uranyl phosphate (HUO2PO4). Subsequently,
HUO2PO4-laden cells removed Ni2+ from dilute aqueous flows via intercalation of
Ni2+ into the HUO2PO4 lattice. Despite comparable acid phosphatase activity in
all three strains, the E. coli DH5 alpha (phoN) construct was superior to
Citrobacter N14 in both uranyl and nickel accumulation, while the E. coli DH5
alpha (phoC) construct was greatly inferior in both respects. Expression of
phosphatase activity alone is not the only factor that permits efficient and
prolonged metal phosphate accumulation, and the data highlight possible
differences in the PhoN and PhoC phosphatases, which are otherwise considered to
be related in many respects.
PMID- 9763696
TI - Virus removal from bioproducts using ultrafiltration membranes modified with
latex particle pretreatment.
AB - Ultrafiltration is an attractive process for virus removal from bioproducts owing
to its high throughput as well as the fact that the operation is carried out
under ambient conditions (damage to proteins is highly limited). The principal
concern regarding the adoption of conventional ultrafiltration membranes for
virus removal is the possibility of the virus passing through abnormally large
pores or surface imperfections on the membrane surface. The chief principle
behind the present work is to pretreat the membrane by blocking the abnormally
large pores using latex particles. Experimental work was conducted to validate
this pretreatment using the bacteriophage phi x 174 as a model virus. The results
attained were highly encouraging. Different sizes of latex particles were tested
by treating a 100 KD molecular weight cut-off membrane, and the transmission of
phage (suspended in buffer) through this membrane assessed. In the absence of any
particle pretreatment, a virus clearance of 4.78 log reduction value was observed
for this membrane. The transmission of phage through the membrane could be
reduced by an order of magnitude using 0.11 micron latex particles, or two orders
of magnitude using a combination of 0.11 and 0.50 micron particles. The
application of latex particles did not hinder the transport of protein through
the 100 KD membrane. Protein sieving coefficients obtained using this membrane
were 91%, 16% and 2%, for lysozyme, HSA and IgG, respectively.
PMID- 9763698
TI - Weak affinity chromatography of small saccharides with immobilised wheat germ
agglutinin and its application to monitoring of carbohydrate transferase
activity.
AB - In this work we have evaluated the potential to use wheat germ agglutinin (WGA)
for weak affinity chromatography (WAC) of N-acetyl derivatives of mono-, di-, tri
and tetrasaccharides. WGA was used as a ligand in a high performance liquid
affinity chromatography (HPLAC) system. Isocratic affinity chromatography was
conducted where similar N-acetyl saccharides were separated according to their
binding strength to WGA. Affinities are weak and lie typically in the mM range.
For example, for 3'sialyllactose, the dissociation constant (Kd) was found to be
2.4 mM at 8 degrees C. It was interesting to note that the WGA-HPLC column can
distinguish between the anomeric forms of N-acetylglucosamine. Weak affinity
chromatography with immobilised WGA was used in an enzyme assay to detect the
activity of GlcNAc-transferases.
PMID- 9763699
TI - Ribose-5-phosphate isomerase from Saccharomyces cerevisiae: purification and
molecular analysis of the enzyme.
AB - Purification and molecular analysis of ribose-5-phosphate isomerase (EC 5.3.1.6)
from Saccharomyces cerevisiae is described first time. The enzyme was enriched
from a haploid deletion mutant containing the wild-type gene on a multicopy
plasmid elaborating the following steps: ammonium sulphate precipitation,
interfacial salting out on Sepharose 6B, high performance liquid chromatography
on Fractogel EMD DEAE and on Resource Phenyl. The enzyme activity was found to be
rather unstable possibly caused by removal of stabilizing cofactors or proteins
during the purification procedure. The purified enzyme showed a hyperbolic
dependence on the substrate ribose-5-phosphate with a K(m)-value of 1.6 +/- 0.3
mmol/l. For the native enzyme a molecular mass of 115 +/- 10 kDa was determined
as found by saccharose density gradient centrifugation, sedimentation equilibrium
analysis, size exclusion chromatography and polyacrylamide gel electrophoresis.
Sodium dodecyl sulphate polyacrylamide gel electrophoresis and Western blotting
revealed one band with a molecular mass of 31 +/- 2 kDa. Thus, the native enzyme
is composed of four subunits of identical size. The molecular mass of the subunit
and the identified N-terminal sequence of 33 amino acids fits well the 258 amino
acid protein encoded by the S. cerevisiae RKI open reading frame, which was
characterized previously only by increasing specific activities of ribose-5
phosphate isomerase in cells after cloning the gene. On the basis of the
conserved amino acids an alignment of the amino acid sequence of ribose-5
phosphate isomerase from yeast with those of the enzyme from mouse, spinach and
Escherichia coli is presented.
PMID- 9763700
TI - IgG and hybridoma partitioning in aqueous two-phase systems containing a dye
ligand.
AB - The effect of the important ATPS- and buffer parameters on IgG and hybridoma
partitioning in ATPSs containing a PEG-dye-ligand was studied. Objective was to
establish selection criteria for effective ligands for extractive fermentations
with animal cells in ATPSs. In the presence of 1% PEG-dye-ligand the binding of
IgG to the PEG-ligand was affected severely by the Na-chloride concentration. The
tie-line length and pH affected IgG partitioning to a lesser extent. The desired
partitioning of IgG into the top phase, was only obtained when, in addition to
the 10 mmol/kg K-phosphate buffer, no Na-chloride was present. In an ATPS culture
medium, with +/- 35 mmol/kg Na-bicarbonate and 60 mmol/kg Na-chloride, increasing
the PEG-dye-ligand concentration up to 100% did increase the partition
coefficient, but was not effective in concentrating the IgG in the top phase of
ATPS culture medium at a pH of 7.8. Furthermore, addition of the PEG-dye-ligand
to ATPS culture medium changed the hybridoma cell partitioning from the bottom
phase to the interface.
PMID- 9763701
TI - Segment-specific retention of a larval neuromuscular system and its role in a
new, rhythmic, pupal motor pattern in Manduca sexta.
AB - At pupation in Manduca sexta, accessory planta retractor muscles and their
motoneurons degenerate in segment-specific patterns. Accessory planta retractor
muscles in abdominal segments 2 and 3 survive in reduced form through the pupal
stage and degenerate after adult emergence. Electromyographic and
electrophysiological recordings show that these accessory planta retractor
muscles participate in a new, rhythmic 'pupal motor pattern' in which all four
muscles contract synchronously at approximately 4 s intervals for extended bouts.
Accessory planta retractor muscle contractions are driven by synaptic activation
of accessory planta retractor motoneurons and are often accompanied by rhythmic
activity in intersegmental muscles and spiracular closer muscles. The pupal motor
pattern is influenced by descending neural input although isolated abdominal
ganglia can produce a pupal motor pattern-like rhythm. The robust pupal motor
pattern first seen after pupal ecdysis weakens during the second half of pupal
life. Anemometric recordings indicate that the intersegmental muscle and
spiracular closer muscle component of the pupal motor pattern produces
ventilation. Accessory planta retractor muscle contractions lift the flexible
abdominal floor, to which the developing wings and legs adhere tightly. We
hypothesize that, by a bellows-like action, the accessory planta retractor muscle
contractions circulate hemolymph in the appendages. Morphometric analysis shows
that dendritic regression is similar in accessory planta retractor motoneurons
with different pupal fates, and that accessory planta retractor motoneurons begin
to participate in the pupal motor pattern while their dendrites are regressed.
PMID- 9763702
TI - Auditory role of the suprabranchial chamber in gourami fish.
AB - Fish hearing specialists (e.g., goldfish, holocentrids, clupeoids, mormyrids)
have evolved specialized structures (e.g., Weberian ossicles, swimbladder
diverticulae, gas-filled bullae) to enhance their auditory frequency range and
threshold sensitivity. The inner ears of anabantoid fish are encased in
membranous cranial bones and are protruded into air-filled suprabranchial
chambers. This research was intended to test the hypothesis that the gas bubbles
inside the suprabranchial chambers may modulate the hearing abilities of
anabantoid fish because of their proximity to the membranous bone-encased inner
ears. Three species of gourami (blue gourami Trichogaster trichopterus; kissing
gourami Helostoma temminckii; dwarf gourami Colisa lalia) were examined. Using
the auditory brainstem response recording technique, baseline audiograms tested
at 300, 500, 800, 1500, 2500, 4000 Hz were obtained. The air bubbles in the
suprabranchial chambers were replaced by water, and the audiograms were
remeasured. Thresholds were elevated in all three species. When three blue
gouramis were allowed to replenish air into the suprabranchial chambers their
hearing abilities returned to baseline levels. These results support the
hypothesis that air bubbles in the suprabranchial chambers can affect hearing
abilities of gouramis by lowering the thresholds.
PMID- 9763703
TI - Dipole source localization by mottled sculpin. III. Orientation after site
specific, unilateral denervation of the lateral line system.
AB - To test the hypothesis that spatial excitation patterns along the lateral-line
system underlie source localization, we videotaped the orientation behavior of
blinded mottled sculpin in response to a small dipole source (50-Hz vibrating
sphere) before and after unilateral denervation of the lateral line system on
different body regions (head, trunk and head + trunk). Approach pathways were
qualitatively similar to those followed by normal intact animals. Abnormal
behavior (turning in circles) was not observed. However, the frequency with which
fish placed their intact side facing the source increased by 12-89%, depending on
the denervation site. The angular accuracy of orientation decreased by 20 degrees
to 60 degrees (100% to 370% change) depending on source location and region of
lateral line denervated. Deficits tended to be site-specific. For example,
unilaterally denervating lateral-line organs on the head resulted in less
accurate orienting responses when the source was located on the denervated side
of the head, but not on the opposite side of the head or on either side of the
trunk. Site-specific deficits and the absence of abnormal approach pathways argue
that animals are relying on a point-by-point spatial representation of source
location along the sensory surface rather than computations based on bilateral
comparisons.
PMID- 9763704
TI - Visual acuity, contrast sensitivity and retinal magnification in a marsupial, the
tammar wallaby (Macropus eugenii).
AB - The visual acuity of the tammar wallaby was estimated using a behavioural
discrimination task. The wallabies were trained to discriminate a high-contrast
(86%) square-wave grating from a grey field of equal luminance (1000-6000 cd m
2). Visual-evoked cortical potentials were used to measure the complete contrast
sensitivity function. The stimulus was a sinusoidal phase reversal of a
sinusoidally modulated grating of various spatial frequencies and contrasts with
a mean luminance of 40 cd m-2). The behavioural acuity was estimated to be about
4.8 cycles/deg. The contrast sensitivity peaked at about 0.15 cycles/deg and
declined towards both lower and higher spatial frequencies. The cut-off frequency
of the contrast sensitivity function is slightly lower than the behaviourally
measured acuity at about 2.7 cycles/deg. The retinal magnification factor was
estimated anatomically from laser lesions to be about 0.16 mm/deg. Based on the
known ganglion cell density and the retinal magnification factor, an anatomical
upper limit to visual acuity of about 6 cycles/deg can be calculated. The
differences in estimates of visual acuity between the behavioural and anatomical
methods on the one side and physiology on the other side are discussed.
PMID- 9763705
TI - Indole-3-acetic acid is synthesized from L-tryptophan in roots of Arabidopsis
thaliana.
AB - The promoter of the nit1 gene, encoding the predominantly expressed isoform of
the Arabidopsis thaliana (L.) Heynh. nitrilase isoenzyme family, fused to the
beta-glucuronidase gene (uidA) drives beta-glucuronidase expression in the root
system of transgenic A. thaliana and tobacco plants. This expression pattern was
shown to be controlled developmentally, suggesting that the early differentiation
zone of root tips and the tissue surrounding the zone of lateral root primordia
formation may constitute sites of auxin biosynthesis in plants. The root system
of A. thaliana was shown to express functional nitrilase enzyme. When sterile
roots were fed [2H]5-L-tryptophan, they converted this precursor to [2H]5-indole
3-acetonitrile and [2H]5-indole-3-acetic acid. This latter metabolite was further
metabolized into base-labile conjugates which were the predominant form of [2H]5
indole-3-acetic acid extracted from roots. When [1-13C]-indole-3-acetonitrile was
fed to sterile roots, it was converted to [1-13C]-indole-3-acetic acid which was
further converted to conjugates. The results prove that the A. thaliana root
system is an autonomous site of indole-3-acetic acid biosynthesis from L
tryptophan.
PMID- 9763706
TI - Sub-cellular immunolocalization of the glucosinolate sinigrin in seedlings of
Brassica juncea.
AB - Polyclonal rat antibodies were raised to a bovine serum albumin-sinigrin
conjugate and used to immunolocalize sinigrin (2-propenylglucosinolate) in
imbibed seeds and developing seedlings of Brassica juncea. (L.) Czern. Sinigrin
was localized to protein bodies in aleurone-like cells but shown to be absent
from myrosin cells. Double labelling techniques were used to co-localize both
myrosinase (beta-thioglucoside glucohydrolase, EC 3.2.3.1) and sinigrin. Myrosin
grains were labelled only with the anti-myrosinase antibody, but aleurone cells
were labelled with both anti-myrosinase and anti-sinigrin antibodies. High
performance liquid chromatographic analysis of conventionally fixed and
dehydrated seed tissues (4 h post imbibition in water), indicated a high
proportion of sinigrin was retained in fixed tissues. Over a time course of 100
h, protein bodies within aleurone-like cells degraded, fused to form the cell
vacuole and lost all myrosinase labelling but retained residual sinigrin
labelling. The degradation of protein bodies corresponded to a decrease in
retention of sinigrin in the fixed tissues. The results describe for the first
time the co-localization of a plant enzyme and its substrate, a secondary
metabolite.
PMID- 9763707
TI - Effect of aluminum on cytoplasmic Ca2+ homeostasis in root hairs of Arabidopsis
thaliana (L.).
AB - Aluminum inhibition of root growth is a major world agricultural problem where
the cause of toxicity has been linked to changes in cellular calcium homeostasis.
Therefore, the effect of aluminum ions (Al) on changes in cytoplasmic free
calcium concentration ([Ca2+]c) was followed in root hairs of wild-type, Al
sensitive and Al-resistant mutants of Arabidopsis thaliana (L.) Heynh. Generally,
Al exposure resulted in prolonged elevations in tip-localized [Ca2+]c in both
wild-type and Al-sensitive root hairs. However, these Al-induced increases in
[Ca2+]c were not tightly correlated with growth inhibition, occurring up to 15
min after Al had induced growth to stop. Also, in 32% of root hairs examined
growth stopped without a detectable change in [Ca2+]c. In contrast, Al-resistant
mutants showed little growth inhibition in response to AlCl3 exposure and in no
case was a change in [Ca2+]c observed. Of the other externally applied stresses
tested (oxidative and mechanical stress), both were found to inhibit root hair
growth, but only oxidative stress (H2O2, 10 microM) caused a prolonged rise in
[Ca2+]c similar to that induced by Al. Again this increase occurred after growth
had been inhibited. The lack of a tight correlation between Al exposure, growth
inhibition and altered [Ca2+]c dynamics suggests that although exposure of root
hairs to toxic levels of Al causes an alteration in cellular Ca2+ homeostasis,
this may not be a required event for Al toxicity. The elevation in [Ca2+]c
induced by Al also strongly suggests that the phytotoxic action of Al in root
hairs is not through blockage of Ca2(+)-permeable channels required for Ca2+
influx into the cytoplasm.
PMID- 9763708
TI - Molecular cloning of the cDNA coding for the (R)-(+)-mandelonitrile lyase of
Prunus amygdalus: temporal and spatial expression patterns in flowers and mature
seeds.
AB - A gene highly expressed in the floral organs of almond (Prunus amygdalus Batsch),
and coding for the cyanogenic enzyme (R)-(+)-mandelonitrile lyase (EC 4.1.2.10),
has been identified and the full-length cDNA sequenced. The temporal expression
pattern in maturing seeds and during floral development was analyzed by RNA blot,
and the highest mRNA levels were detected in floral tissues. The spatial mRNA
accumulation pattern in almond flower buds was also analyzed by in-situ
hybridization. The mRNA levels were compared during seed maturation and floral
development in fruit and floral samples from cultivars classified as homozygous
or heterozygous for the sweet-almond trait or homozygous for the bitter trait. No
correlation was found between these characteristics and levels of mandelonitrile
lyase mRNA, suggesting that the presence of this protein is not the limiting
factor in the production of hydrogen cyanide.
PMID- 9763711
TI - Purification of a nitrate reductase kinase from Spinacea oleracea leaves, and its
identification as a calmodulin-domain protein kinase.
AB - Spinach (Spinacea oleracea L.) nitrate reductase (NR) is inactivated by
phosphorylation on serine-543, followed by binding of the phosphorylated enzyme
to 14-3-3 proteins. We purified one of several chromatographically distinct
NRserine-543 kinases from spinach leaf extracts, and established by Edman
sequencing of 80 amino acid residues that it is a calcium-dependent (calmodulin
domain) protein kinase (CDPK), with peptide sequences very similar to Arabidopsis
CDPK6 (accession no. U20623; also known as CPK3). The spinach CDPK was recognized
by antibodies raised against Arabidopsis CDPK. Nitrate reductase was
phosphorylated at serine-543 by bacterially expressed His-tagged CDPK6, and the
phosphorylated NR was inhibited by 14-3-3 proteins. However, the bacterially
expressed CDPK6 had a specific activity approx. 200-fold lower than that of the
purified spinach enzyme. The physiological control of NR by CDPK is discussed,
and the regulatory properties of the purified CDPK are considered with reference
to current models for reversible intramolecular binding of the calmodulin-like
domain to the autoinhibitory junction of CDPKs.
PMID- 9763713
TI - A cysteine endopeptidase with a C-terminal KDEL motif isolated from castor bean
endosperm is a marker enzyme for the ricinosome, a putative lytic compartment.
AB - A papain-type cysteine endopeptidase with a molecular mass of 35 kDa for the
mature enzyme, was purified from germinating castor bean (Ricinus communis L.)
endosperm by virtue of its capacity to process the glyoxysomal malate
dehydrogenase precursor protein to the mature subunit in vitro (C. Gietl et al.,
1997, Plant Physiol 113: 863-871). The cDNA clones from endosperm of germinating
seedlings and from developing seeds were isolated and sequence analysis revealed
that a very similar or identical peptidase is synthesised in both tissues.
Sequencing established a presequence for co-translational targeting into the
endoplasmic reticulum, an N-terminal propeptide and a C-terminal KDEL motif for
the castor bean cysteine endopeptidase precursor. The 45-kDa pro-enzyme stably
present in isolated organelles was enzymatically active. Immunocytochemistry with
antibodies raised against the purified cysteine endopeptidase revealed highly
specific labelling of ricinosomes, organelles which co-purify with glyoxysomes
from germinating Ricinus endosperm. The cysteine endopeptidase from castor bean
endosperm, which represents a senescing tissue, is homologous to cysteine
endopeptidases from other senescing tissues such as the cotyledons of germinating
mung bean (Vigna mungo) and vetch (Vicia sativa), the seed pods of maturing
French bean (Phaseolus vulgaris) and the flowers of daylily (Hemerocallis sp.).
PMID- 9763714
TI - Identification of sequence homology between the internal hydrophilic repeated
motifs of group 1 late-embryogenesis-abundant proteins in plants and hydrophilic
repeats of the general stress protein GsiB of Bacillus subtilis.
AB - Late embryogenesis abundant (LEA) proteins are speculated to protect against
water stress in plants. Group 1 LEA proteins are hydrophilic and vary mainly in
the numbers of an extremely hydrophilic internal 20-amino-acid motif. This motif
is present up to four times in Arabidopsis thaliana and Hordeum vulgare Group 1
proteins and has been described in numerous plant species. However, no similarity
has yet been described between Group 1 genes or gene products and those from non
plant species. We report here the striking similarity between the repeated
internal motif of Group 1 LEA proteins and a repeated hydrophilic motif present
in a stress-related protein (GsiB) from Bacillus subtilis.
PMID- 9763716
TI - [The 28th Western regional meeting and 28th Eastern regional meeting of the
Japanese Society of Nephrology. 1998. Abstracts].
PMID- 9763715
TI - [The 33rd conference of Japanese Medical Society of Alcohol and Drug Studies.
August 28-30, 1998. Osaka, Japan. Abstracts].
PMID- 9763717
TI - [40th Annual meeting of the Japan Geriatrics Society. Fukuoka, Japan. June 17-19,
1998. Abstracts].
PMID- 9763718
TI - Interventions to improve the use of antimalarials in south-east Asia: an
overview.
AB - There are few drugs for malaria, and those which are available for use are
subject to rapid development of resistance. Curiously, little effort has been
made to improve drug use in malaria-endemic countries and to assess the benefits
of such improvements. Advances can be made in public understanding of the value
of ingesting a full regimen of antimalarials, in order to achieve complete cure,
and in improving simple technologies (blister packaging) to achieve the same
result. Better efforts can be made to reduce the availability of fake or
substandard drugs in the marketplace. In this article, we describe the outcome of
a concerted effort to improve drug compliance and drug quality in an area of
multidrug resistance for malaria. These research efforts, guided by the Task
Force for Improved Use of Antimalarials, characterized the problems in drug
compliance in South-East Asia, and developed interventions to improve drug use in
the various countries. Interventions involved drug packaging, public information
campaigns, and assessments of drug quality. Results show that blister packaging
worked best to improve drug compliance and that the increased cost of packaged
medication did not limit its use. Drug quality was a major problem in unregulated
countries and should be improved.
PMID- 9763719
TI - The effect of drug packaging on patients' compliance with treatment for
Plasmodium vivax malaria in China.
AB - A study conducted in 1994 showed that the use of blister packs containing
antimalarial drugs significantly increased patients' compliance, compared with
traditional means of dispensing drugs in a paper envelope. The present study
assessed patients' compliance and compared the difference between 3-day
chloroquine and 8-day primaquine courses of treatment for vivax malaria. The
level of real compliance was determined by making the drugs with phenobarbital,
and measuring its level in the blood following treatment. The results show that
blister packaging significantly improved patients' compliance (p < 0.001) over
traditional means of dispensing antimalarial drugs; there was no difference in
treatment compliance between 3-day and 8-day courses when the drugs were in
blister packs. However, with ordinary packaging the treatment compliance rate for
an 8-day course was significantly less than for a 3-day course (P < 0.05).
PMID- 9763720
TI - Childhood malaria in the Lao People's Democratic Republic.
AB - The idea that malaria in South-East Asia is synonymous with adult malaria is
questioned in this paper. In the Lao People's Democratic Republic, community
based malariometric data were collected in Savannakhet Province, which shares
borders with Viet Nam in the east and Thailand in the west. The data indicate
that endemic malaria is rural and stable in large areas of the province. In these
areas, which are rarely subject to malaria control, there is significant
childhood malaria. A little more than one-quarter of individuals examined in mass
blood surveys carried out in the peak malaria season were parasite-positive.
Unlike other studies in the region reporting a declining risk of positive
parasitaemia with age, thus suggesting immunity consistent with high and
prolonged exposure to malaria, the communities studied in the Lao People's
Democratic Republic did not show the expected acquisition of immunity. Further
community-based studies on this matter are therefore warranted.
PMID- 9763721
TI - Influence of blister packaging on the efficacy of artesunate + mefloquine over
artesunate alone in community-based treatment of non-severe falciparum malaria in
Myanmar.
AB - Three studies were carried out to determine the need, acceptability, and efficacy
of adding mefloquine to artemisinin derivatives (AD) for the first-line treatment
of uncomplicated falciparum malaria. The first was a retrospective study of 255
basic health workers which showed that their recommendation of AD to patients
depended on their level of training. None of the paramedics/midwives and only 9%
of 129 doctors had prescribed AD, and no one had recommended AD in combination
with mefloquine; 72% of patients used courses that were too short for
parasitological cure. To promote the addition of mefloquine to AD regimens we
conducted intervention workshops with health care providers and subsidized the
cost of mefloquine to patients. In the second study, we interviewed 200 patients
before and after the intervention to evaluate drug compliance with full doses of
AD and use of subsidized mefloquine. After the intervention, we found that only
3.6% had used mefloquine and 62% had taken non-curative doses of AD. In the third
study, we provided blister packs of medication in daily doses and compared the
intake of AD + placebo (158 patients) with that of AD + mefloquine (222 patients)
for 5 days. The compliance with both regimens was 99%. Blood smears for parasites
on day 28 showed one positive in the AD + mefloquine group and 7 positive in the
AD group. We conclude that provision of blister packs of daily doses is a very
effective way to improve compliance with short courses and drug combinations, but
the efficacy of the combination in Myanmar in this particular study was only
marginally higher than that of AD alone.
PMID- 9763722
TI - Improving compliance with quinine + tetracycline for treatment of malaria:
evaluation of health education interventions in Cambodian villages.
AB - To improve compliance with a 7-day quinine + tetracycline regimen against
malaria, two health education interventions were tested on populations in two
separate groups of villages. In one group, the use of posters and video improved
the compliance rates from 0.5% to 20% (20% effectiveness; 95% confidence interval
(CI), 13-26%); in the other, where posters alone were used, full compliance
changed from 6% to 11% (6% effectiveness; 95% CI, 0-12%). The improved compliance
in the first group occurred mainly among those who went to health practitioners
(effectiveness 40%) rather than drug vendors (effectiveness 2%), although this
could not be attributed to differences in the advice they gave to patients. After
the poster plus video intervention, more patients bought quinine + tetracycline
and received correct advice encouraging the use of a full course; however, not
all of them actually completed the full course by self-administration.
PMID- 9763723
TI - Use and quality of antimalarial drugs in the private sector in Viet Nam.
AB - This study examines the use and quality of antimalarial drugs in the growing
private sector of Viet Nam. The practices of drug vendors (called alternative
treatment providers (ATPs)) as well as their stocks and the quality of drugs sold
by them, and the local production and distribution of antimalarials were
investigated. Antimalarials were sold by the vast majority of ATPs, almost all
the common antimalarials being available for sale. The practices and indications
for sale, however, varied. Underdosing for malaria was frequent in all three
provinces studied, and lack of knowledge of the appropriate regimen for cure was
common among the drug-sellers. Samples of antimalarials were collected from ATP
outlets in the three provinces, and the drugs were assessed for their contents
and expiry date by the Institute of Drug Quality Control in Hanoi. Of the 218
samples of drugs examined by the Institute, over 96% met the quality
requirements. However, a 10% sample of these drugs were independently assessed by
WHO and revealed a different picture: 70% of them failed to meet the standard
specifications required. There is therefore an urgent need to improve the
capability and monitoring procedures of bodies involved in assessing and
regulating drugs in Viet Nam.
PMID- 9763724
TI - Compliance with artesunate and quinine + tetracycline treatment of uncomplicated
falciparum malaria in Thailand.
AB - A randomized, controlled, malaria-clinic-based field trial was conducted to
compare compliance with a 7-day quinine + tetracycline regimen and a 5-day 700-mg
artesunate regimen for the treatment of uncomplicated falciparum malaria in a
community in Thailand. Of 137 patients, aged 15-60 years attending a malaria
clinic, 77 received artesunate and 60 received quinine + tetracycline. Compliance
and cure rates were evaluated on days 5 (artesunate) and 7 (quinine +
tetracycline) using patient interview/residual pill counts and peripheral blood
smear, respectively. Data were analysed using the intention-to-treat approach,
and the reasons for compliance and noncompliance were investigated. Compliance
was significantly higher (98.4%) with artesunate than with quinine + tetracycline
(71.7%) (relative risk adjusted for sex (aRR) = 1.39 (95% C.I. = 1.15-1.68);
referent: quinine + tetracycline). Cure rate (100%) was higher in those receiving
artesunate than quinine + tetracycline (77.4%) (aRR = 1.32 (95% C.I. = 1.12
1.55)). Reasons for compliance included the desire to be cured and to follow the
advice of malaria staff/employer, and the simple dosing regimen. Noncompliance
was mostly due to adverse reactions and forgetting to take the drugs. These
results can serve as a baseline for designing and evaluating new interventions to
improve compliance, as well as for studying cost-effectiveness to help drug
policy decision-making. We recommend a strategy which integrates a short-course,
once-a-day regimen (with minimal adverse reactions), a better delivery system for
antimalarial drugs and health education, and an enhanced advisory role of malaria
staff. Considering the higher compliance rate and curative effectiveness of
artesunate, we recommend its use instead of quinine + tetracycline for the
treatment of uncomplicated malaria in clinics in Thailand.
PMID- 9763725
TI - Initial evaluation of low-dose phenobarbital as an indicator of compliance with
antimalarial drug treatment.
AB - Since poor compliance with antimalarial therapy is often suspected but difficult
to prove, this study attempted to establish a model for predicting the plasma
concentration of phenobarbital (given in low doses in conjunction with the drug)
as an indicator of compliance. Phenobarbital was chosen because its value had
been demonstrated as a marker of compliance in long-course therapies, any
significant departure from steady-state concentrations (achieved with full
compliance) indicating one or more missed doses. Therapy for uncomplicated
malaria varies from 5 days with artesunate to 7 days with quinine + tetracycline.
Volunteers with confirmed falciparum malaria were randomized into 5 groups and
given malaria therapy as well as phenobarbital daily for 3-7 days. Plasma samples
for determination of phenobarbital concentrations were taken just prior to the
daily dose of phenobarbital. Although there was a clear and predictable
individual pattern of blood concentrations following each dose of phenobarbital,
inter-individual variation in blood levels was significant and reduced their
predictive value beyond the second day's dose. The cause of the variations is not
clear; it could be attributable to different sources of the drug, previous intake
of phenobarbital by the patient, or differences in drug absorption and
disposition in malaria patients. Results for the 5-day artesunate regimen suggest
that phenobarbital may be useful as a marker of compliance if the patient stops
medication after 3 days; clear differences were evident at the end of the course
of treatment between plasma phenobarbital concentrations in individuals
completing the 5-day course and those who stopped after 3 days. For the quinine
tetracycline regimen, results suggest that it may be possible to discriminate
between subjects where there is a 3-day difference in treatment. Phenobarbital is
a better discriminant when dosing is every 24 hours as with artesunate, rather
than the 8-hourly regimen for quinine-tetracycline. When measuring compliance for
malaria treatment, if it is important to know what proportion of patients reach
3, 5 or 7 days of compliance, then phenobarbital might have a role to play in
this assessment, but further investigations in more patients would be required.
Alternatively, different markers could be used for the doses to be given on these
days and, as long as the patient does not mix the doses for the different days,
sequential doses and determination of compliance could be based on an "all or
none" detection of the marker rather than on drug levels.
PMID- 9763726
TI - Diphtheria in visitors to Africa.
PMID- 9763727
TI - Surveillance of overwhelming post-splenectomy infection.
PMID- 9763728
TI - [Proceedings of the 26th Seminar on Environmental Hygiene. "Ecological Animal
Raising" Hannover, 27 February 1998].
PMID- 9763729
TI - [Consumer demands concerning meat between price and ethics].
AB - A review is given about consumer demands on meat. Mainly the problems of
decreasing meat consumption, health aspects and special questions of ecological
products are considered. The market gives evidence of a further drop in meat
consumption and a more consistent differentiation of product lines. Eco-products,
emphasising the animal welfare aspect, will have their place in that context but
persist in the state of a minor market segment. Nevertheless it has to be
expected, that also the conventional products will increasingly comply to modern
consumer demands.
PMID- 9763730
TI - [Characteristic features of ecological animal husbandry].
AB - In recent years conventional livestock farming has been impressively successful
referring to the increase in performance of farm animals and to the decrease in
production costs. On the contrary, following the dictate of production
intensification, animal health and welfare as well as environmentally friendly
production have been pushed into the background because of being cost- and labour
intensive. Evaluations of animal health status of farm animals indicate that a
considerable number of farm animals cannot cope with the requests of increase in
performance. This may be due either to physiological limits or inadequate housing
and management conditions. Ecological animal husbandry as an integrative Part of
organic farming is an alternative to the previous development, aiming at high
quality standards concerning animal health and welfare as well as environmentally
friendly production. Farmers have to follow the code of practice before being
entitled to label their products as organic food and demand for premium prices.
The willingness of an increasing number of consumers to pay premium prices
enables the farmers to balance the economical pressure on the production costs
and on the yields of the farm animals. While the code of practice limits the
amount of area-born products, options are gained for the optimization of the
production process for the benefit of the farm animals and the environment. The
capacities of ecological animal husbandry for high process quality standards are
discussed hypothetically. Due to the phenomenon of various influences and
interactions there is still a lack of methodology in order to assess the process
qualities and the implications of different farming strategies in a complex and
objective manner, resulting in a new challenge for natural science to establish a
methodology that enables a more comprehensive approach.
PMID- 9763731
TI - [Provision of a legal framework for ecological animal husbandry].
AB - Since 1991 the Regulation (EEC) no. 2092/91 on organic production of agricultural
products is applied for plants and plant products. Because of the increasing
consumer's demand this regulation has to be supplemented by the area of livestock
production. At present an amended commission proposal is discussed which also
includes the amendments of the European Parliament. Besides the general
principles of livestock production in organic farming the conversion periods from
conventional to organic farming, the origin of the animals, feed and supplements,
veterinary treatments as well as housing conditions for livestock are described.
The negotiations in Brussels will have to achieve a compromise which gives a
clear distinction from conventional livestock production, and which allows as
many farms as possible, that are producing according to the rules of organic
farming under various conditions within the EU member states, to proceed with
minor adaptations to the new regulation.
PMID- 9763732
TI - [Ecological animal husbandry--main developmental points for production and
marketing as in the example of the Bioland Association].
AB - The data from Bioland are presented as an example of the development in
ecological animal husbandry. Dairy cows (29.000 in 1000 dairy farms) are typical
in organic farming. In the past 4 years there has been an annual increase in
dairy farming of about 6.5%. The increase is even higher in suckled cows and
laying hens (both 23% annually), or apiculture. Pigs have been of minor
importance, but are gaining more interest recently. In each category the number
of animals is growing faster than the number of farms. In ecological husbandry,
specialisation of personnel has to go hand in hand with improvements in keeping,
feeding, hygiene, health of animals, integration of farming and stock breeding
and documentation to cope with the demands of the market. The standard aimed for
is dictated by the actual current state of knowledge in the ecological and
ethological sciences. There are various possibilities for consultations and there
are regional groups of specialists to provide know-how to the farmers.
Ecologically produced goods are economically undersubsidised compared to
conventionally produced ones. However, the development of the market is
correlated with the production. The number of butcher's and dairies that have
contracts with ecological associations has clearly been increasing lately. A high
percentage of the raw products as well as food processed on the farm is sold
directly by the farmers, however, there is a slow trend towards the retail trade.
Various possibilities of improving the market are discussed. Ecological husbandry
offers especially good conditions to farmers with high activity in marketing. The
system of control is developing steadily according to the increasing demands in
quality of production and products. As a result of good cooperation between
farmers, control institutions and Bioland, practical solutions can be found to
most problems. A list of high priority future work, investigation and development
is given. All costs that arise during production and processing have to be
internalised to widely realise ecological farming especially animal production in
favour of environmental protection. Furthermore, farmers need an intensive
education in agrarian ecology.
PMID- 9763733
TI - [Special features of feeding in ecologic animal husbandry].
AB - Food produced in ecological agriculture becomes popular more and more. In the
interest of consumers (to protect against deception) and of producers (to
contrast with conventionally produced food) it is necessary to define the
conditions and circumstances when products can be declared as ecological. Up to
now definitions of housing and feeding animals in organic agriculture only are
set up by private organizations and associations, but in the future we will have
a direction of the European community (Nr. 2092/91 EWG), extended by directives
and restrictions focussed on animal husbandry and feeding. Aim of this
contribution is to give information on special restrictions on feeds and feeding
of food producing animals in organic agriculture (preconditions in the case that
labelling as "ecologically produced" is intended). Conventionally produced
feedstuffs are restricted, common complete diets and some special feed additives
(for example growth promoters) are not allowed. Feeding according to species
specific requirements (herbivorous animals) as well as according to age and
development (for example minimum duration of suckling periods) is intended. On
the other hand there is a conscious renunciation of maximizing animals'
performance (and plant yields). Consequences, risks and conflicts of different
aims in feeding in accordance with ideas of organic agriculture are discussed.
Various efforts at sustainability of conventional agriculture are influenced
markedly by ideas and concepts established in organic agriculture primarily.
PMID- 9763734
TI - [Animal rights and animal health on ecological farms].
AB - Intensive animal husbandry is criticized in relation to the fulfillment of the
animals needs. The guidelines of the organizations of organic agriculture offer
the opportunity for better animal welfare. In this paper an overview is given
concerning animal health and welfare on organic farms with dairy cows, fattening
pigs and laying hens. On organic farms housing systems with the potential for a
better animal welfare dominate. In field studies using scoring systems (animal
welfare index) organic farms reach more points than conventional ones. However,
animal health on average is not much better on organic farms. The health problems
discussed in the paper are mainly caused by management problems. Therefore,
improvements are possible.
PMID- 9763736
TI - [Economic management estimate of different environmentally-friendly animal
husbandry systems].
AB - This contribution compares conventional and ecological animal production systems.
This financial analysis considers dairy farming and pig production and takes into
account the individual options and aims of the farms. The profitability changing
a conventional animal production system to an ecological system depends on many
different parameters. A general statement with regard to all farms and farm
systems is not possible. In addition to the farmers qualification, the marketing
options, the location of the farm, the mode of operation and the financial
situation when change to ecological production is envisaged determine prospects
for success and profitability.
PMID- 9763737
TI - [Quality of ecologically produced foods of animal origin].
AB - The production of organic (ecological) food of animal origin is done in many ways
and uses many different breeds. Therefore a real comparison with conventionally
produced food is difficult. From the limited number of published data it appears,
that the characteristics of quality of the products, the nutritional, hygienic,
sensorial and technological factors, are not very different in both systems of
production. In some factors organic food gets better marks, in others the
conventionally produced food. The differences are in the production system
(process quality) during lifetime of the animals.
PMID- 9763735
TI - [Guidelines for prevention and therapy in ecological animal farms as in the
example of bovine mastitis].
AB - In ecological farming mastitis is the dominating disease in dairy cattle. The
regular prophylactic use of antibiotics in farm animals is forbidden, in therapy
antibiosis is restricted. A solution of this problem could be a program of
systematic homeopathic prophylaxis as well as a standardised homeopathic
treatment. The example of chronic catarrhal staph.-aureus-mastitis shows that
there is only a certain expectancy of success by homeopathy as well as by any
other medication, if the medication is combined with necessary sanitation
measures. The prognosis for a homeopathic treatment is less favourable if the
sanitation measures are realised incompletely. The possible negative effects of a
false homeopathic medication are described.
PMID- 9763738
TI - [Perspectives of ecological animal husbandry--limits of ecological animal
husbandry].
AB - Farms working under ecological conditions are as well as conventional farms a
part of agriculture. Ecological farming is a response to the special requirements
and ideas of consumers regarding environmental and nature related issues in
primary agricultural production. Its products should be clearly defined so that
they can be differentiated from conventional products. The limits of ecological
livestock farming are set among others by comparably higher production costs,
special management requirements, specific conditions from retailers in respect of
quality and quantity and a limited demand. To further popularize ecological
agriculture, the various individual interests must be focused and common
strategies must be developed. To successfully claim market shares, the
ecologically produced commodities must have a permanent advantage compared to
conventional products-this will not be easy to achieve.
PMID- 9763739
TI - [Post-antibiotic effect. A factor with clinical applications or simply a
laboratory curiosity?].
PMID- 9763740
TI - [Detection of pathogenicity factors in strains of classical enteropathogenic
Escherichia coli].
AB - OBJECTIVE: To determine the number of strains of classic enteropathogenic E. coli
(EPEC) that have the eae gene, that is considered a pathogenicity factor.
MATERIAL AND METHODS: The presence of the eae gene has been evaluated on 62 EPEC
strains of ten different serogroups, isolated from children with gastroenteritis.
RESULTS: Amplification of the eae gene was positive in 10 out of 62 EPEC strains
analyzed (16%) corresponding to seven different serogroups. DISCUSSION: The low
frequency of the detection of the eae gene on EPEC strains shows the limited
correlation between the pathogenicity and the serogroup of the strains and would
corroborate the need to reexamine this subject prospectively in our country.
PMID- 9763741
TI - [Bactericidal activity and capacity for selection of mutants resistant to
imipenmen and meropenem in strains of Proteus, Morganella and Providencia].
AB - BACKGROUND: To compare the bactericidal activity and frequency of mutation for
meropenem and imipenem against Proteus mirabilis, Morganella morganii and
Providencia rettgeri. MATERIAL AND METHODS: Minimum inhibitory concentrations
(MIC) were determined by agar dilution method. Bactericidal activities were
evaluated by killing curves method employing 4 and 16x MIC. One-step resistant
mutant selection was performed by spreading more than 5 x 10(8) UFC/ml on cystine
lactose-electrolyte deficient agar containing 4 times the MIC of meropenem or
imipenem. RESULTS: MIC were 8 to 16 times lower for meropenem. After 24 h,
bactericidal activity was observed for meropenem at 4 and 16 x MIC against 76.7
and 100% of the strains in comparison to 26.7 and 83.3% with imipenem. After 24 h
incubation with imipenem, re-growth occurred in 80 and 90% of P. mirabilis and M.
morganii strains, respectively. Imipenem resistant mutants were selected from 3
strains of P. mirabilis. One of them was stable and MIC of meropenem and imipenem
were 8 to 16-fold higher. CONCLUSIONS: From the laboratory point of view we
consider that meropenem is more active against Proteeae because it was more
potent in terms of inhibitory and bactericidal activity. In addition the risk to
select for resistant mutants was significant with imipenem and P. mirabilis.
PMID- 9763743
TI - [Comparison between 2 monoclonal antibodies (clones 95/12 and 1C3 + AYm-1) for
the detection of pp65 antigenemia associated with human cytomegalovirus].
AB - BACKGROUND: A prospective parallel and blind comparative study was carried out to
evaluate the diagnostic efficacy of two available anti-pp65 monoclonal antibodies
(clone 95/12 and the pool 1C3 + AYM-1) for the cytomegalovirus (CMV) antigenemia
assay. MATERIAL AND METHODS: We carried out a comparative study of 107 blood
samples from immunodepressed patients (renal transplant and AIDS patients) with
suspected disseminated infection by CMV. The PMNLs were obtained using the method
of sedimentation in saline dextran. Slides were stained by an indirect
immunofluorescence assay with two commercially available monoclonal antibodies.
RESULTS: Of the 107 blood samples studied 33 (30.8%) had a positive antigenemia
test. The clone 95/12 detected 30 (90.9%) samples and the pool 31 (93.9%), no
statistically significant difference was observed in the sensitivity of two
reagents (p = 0.42). The values of the mean CMV-positive cell count obtained with
the clone 95/12 was 60.6 vs 61.9 with the monoclonal pool (p = 0.026).
CONCLUSIONS: No significant difference was detected between the two commercial
monoclonal antibodies. However the pool detected a slightly superior CMV-positive
cell count.
PMID- 9763742
TI - [Association of Lyme disease with work and leisure activities].
AB - BACKGROUND: The conditions for Lyme disease are ideal in northern Spain, but the
risk factors are not well established. OBJECTIVE: To describe the clinico
epidemiological characteristics of those patients hospitalized with the diagnosis
of Lyme disease in a region of northern Spain (Vizcaya). PATIENTS AND METHODS:
Retrospective analysis of the patients hospitalized with Lyme disease in Vizcaya
between 1989 and 1996. RESULTS: Twenty-six cases met the clinical and serologic
CDC criteria, 21 males and 5 females, with a mean age of 52 years. Neurologic
manifestations were most common (73%), followed by erythema migrans (62%),
arthralgias (38%) and arthritis (15%). Fifty-eight percent of the patients
recalled a tick bite and rural professional or recreational activities were the
main risk factors. Most of the patients did not seek medical help until late in
the disease, which led to greater morbidity. CONCLUSIONS: Increasing number of
Lyme disease cases in northern Spain represents a public health problem. Disease
morbidity could be reduced by targeted education to populations at risk.
PMID- 9763746
TI - [Population structure and bacterial clonality].
PMID- 9763744
TI - [Antibiotic sensitivity of Streptococcus pyogenes in pediatrics].
AB - BACKGROUND: The purpose of this study was to set up the current level of
Streptococcus pyogenes sensitivity, in pediatric patients in our community, to
penicillin, clindamycin, clarithromycin, erythromycin and azithromycin. MATERIAL
AND METHODS: 100 strains were collected between October 1996 to July 1997. 79
were pharyngeal and 21 were non-pharyngeal strains. The MICs were obtained by the
E-test method, and furthermore the results were compared by the Kirby-Bauer
method. RESULTS: All strains were sensitive to penicillin and except one
(inducible resistance) to clindamycin. 19% were resistant to macrolide, without
differences among clarithromycin, erythromycin and azithromycin. From 13 strains
(16.5%) of pharyngeal and 6 (28.5%) from non-pharyngeal samples, 4 of these from
cutaneous samples, showed resistance. 18 of the resistance strains belonged to
novel resistance fenotip and one to 10 inducible fenotip. Only minor
discrepancies about erythromycin and clindamycin were observed between E-test and
Kirby-Bauer methods. CONCLUSIONS: This study confirms a remarkable level of
resistance to macrolides in pediatric patients, mainly in the cutaneous samples.
Due to the reduced prevalence of macrolide-susceptible strains, in vitro
susceptibility testing appears necessary in case of macrolide chemotherapy.
PMID- 9763748
TI - [Pulmonary mass which cavitated after bronchoscopy].
PMID- 9763747
TI - [Intranasal necrotic lesion in a neutropenic patient].
PMID- 9763749
TI - [Psoas abscess caused Actinomyces israelii].
PMID- 9763750
TI - [Endocarditis caused by Moraxella lacunata on the natural and prosthetic valves.
An unusual pathogenesis].
PMID- 9763751
TI - [Cat scratch disease: description of a new case].
PMID- 9763752
TI - [Bacteremia caused by Moraxella catarrhalis].
PMID- 9763753
TI - [Multiple cerebral abscesses with spontaneous emptying into the ventricles and a
good response to meropenem].
PMID- 9763754
TI - [Cerebral abscess caused by Rhodococcus equi in an immunocompetent patient].
PMID- 9763755
TI - [Bacterial meningitis caused by a meningoencephalocele 20 years after a head
injury].
PMID- 9763756
TI - The relevance of recent advances in psychopharmacology for social psychiatry.
PMID- 9763757
TI - [The importance of recent neuropsychological and neurophysiological studies for
social psychiatry].
PMID- 9763758
TI - Relevance of brain imaging studies for social psychiatry.
PMID- 9763759
TI - [Genetic studies and their relevance in social psychiatry].
PMID- 9763760
TI - [Patterns of care in community mental health services in Lombardy].
AB - OBJECTIVE: The analysis aims to study patterns of care of patients in contact
with 5 Psychiatric Services in Lombardy. Four patterns have been identified long
term-high users, non long term-high users, long term-non high users, non long
term-non high users. DESIGN: Data were provided by the regional Psychiatric
Information System. The cohort of patients have been composed by 5,670 patients
included in 1994 one year prevalence. SETTING: Five Psychiatric Services (Merate,
Treviglio, Crema, Desio, Castano Primo) with a total population of 610,184
inhabitants aged over 14. MAIN UTILISED MEASURES: Some sociodemographic and
clinical variables have been taken into consideration for a descriptive analysis;
a multinomial logistic regression model was used to identify the characteristics
of patients associated with different patterns. RESULTS: Long term-high users
were 5.3%, i.e. a mean rate of 4.9/10,000 residents over 14, and absorbed 60% of
resources, the absence of a partner was associated in regression analysis with
this pattern. Non long term-high users were 1.2%, i.e. a mean rate of 1.1/10,000
residents over 14, and absorbed 7.8% of resources; age below 45, unemployment,
absence of a partner, severe mental illness and first contact with Psychiatric
Services in the period 1985-1989 were predictive variables. Long term-non high
users were 23.4%, i.e. a mean rate of 21.6/10,000 residents over 14, and absorbed
18.1% of resources; age below 45, unemployment, living alone, absence of a
partner, severe mental illness and first contact with Psychiatric Services before
1990 were predictive variables. Non long term-non high users were 70.1%, i.e. a
mean rate of 64.8/10,000 residents over 14 and, absorbed 18.1% of resources.
CONCLUSIONS: Data show that on the whole the activity of Psychiatric Services is
addressed to most serious patients, though considerable differences between
Psychiatric Services utilisation may be found. This study highlights the
importance of a regional Psychiatric Information System, that allows the
monitoring in time and in the regional territory of patterns of care.
PMID- 9763761
TI - [Quality evaluation in psychiatric services: a regional system of indicators].
AB - OBJECTIVE: This work proposes a series of indicators, based on routine data
collection system adopted in the Emilia Romagna Region, with the aim of
describing the quality and quantity of psychiatric care and the connections of
psychiatric structures. We are bearing in mind the Plan aimed to Mental Health
Care 1994-1996 and the Efficiency and quality indicators of National Health
System (SSN) devised by the Department of Health of national government. METHOD:
A working group has been instituted by the regional authority to define the
indicators (definition of meaning, formula, danger level, finality, level od
utilisation, data source and frequency of survey, congruent with the regional
information system. RESULTS: We present 105 indicators grouped according to the
psychiatric structure they are aimed at (community centers, acute admissions
wards, semiresidential and residential facilities, former mental hospitals,
district mental health department) and according to code in three lists: 1)
general indicators; 2) probing indicators; 3) outcome indicators. CONCLUSIONS:
This set of indicators though created for local usage is aimed on objectives
defined by the national Department of Health and can therefore be of interest for
other Italian regions. Modular construction permits flexible application ad
adaptation to less complex information systems. Part of this system is since 1977
part of routine information flux in Emilia Romagna.
PMID- 9763762
TI - Linking epidemiology and disability measurement with mental health service policy
and planning.
AB - OBJECTIVE: This article reviews the extent to which epidemiology and disability
measurement can contribute to mental health and service policy and planning.
METHODS: The review explores the information required for local, mental and
international policy and planning in a variety of settings. RESULTS: Epidemiology
and disability measurement are essential to underpin policy and planning that are
responsive to local needs, together with information on service inputs and
processes and health outcomes. CONCLUSIONS: Epidemiology and disability
measurement should be an integral part of the policy and planning process to
support the development of service, and service processes and the measurement of
health outcomes for not only specialist mental health services, but also
activities in primary care, schools and workplaces.
PMID- 9763763
TI - System failure? The problems of reductions in long-stay beds in the UK.
AB - OBJECTIVE: To review the relevant literature on the effects of reductions in long
stay beds on mental health services in the UK. METHOD: A selective literature
review, with particular reference to research conducted by the author and
colleagues at The Sainsbury Centre for Mental Health. RESULTS: The evidence
suggests that the effects of long stay bed reductions should be examined with
regard to 'old' and new long stay patients separately. While the 'old' long stay
who have been most directly effected by these changes have generally fared well;
the 'new' long stay have not. They are currently accumulating in acute inpatient
units, often on general hospital sites, or are rotating in the 'revolving door'
of acute inpatient care and inadequate community supports. Although it is clear
that there is a shortage of acute beds especially in inner city areas many of the
these beds are currently occupied by patients who would be better (and less
expensively) cared for in community alternatives if these were available. The
evidence suggests that it is possible to improve outcomes for this 'new' long
stay group if specific kinds of housing, work and assertive community teams are
provided. CONCLUSIONS: It is concluded that the effects of long stay bed
reductions should be considered in a 'systems perspective. Effective community
services can be established, but in order to achieve effective substitution of
one kind of service for another, there must be a well co-ordinated, clearly
targeted, and technically efficient system. At the present time such services are
rare. However, simply focusing on one element (e.g. beds) is unlikely to produce
cost effective and efficient solutions.
PMID- 9763765
TI - First reported case of hantavirus pulmonary syndrome in Oklahoma.
AB - Hantavirus Pulmonary Syndrome (HPS) is a condition of rapidly progressive
pulmonary failure with a case-fatality rate of almost 50 percent. Rodents serve
as the reservoir for hantaviruses and human infection occurs primarily via
aerosolized virus in rodent excreta. The rodent reservoir for the disease is
widespread across Oklahoma and the first case of HPS has recently been confirmed
in an Oklahoma resident. Physicians should suspect HPS in a previously healthy
person who develops a febrile illness and respiratory insufficiency and has
potentially been exposed to the virus. Common laboratory findings include a left
shifted neutrophilic leukocytosis, elevated hematocrit and thrombocytopenia.
Therapy is supportive. If HPS is suspected, the patient should be immediately
transferred to a facility that can provide aggressive supportive care.
PMID- 9763764
TI - [Medical decisions at the end of life: epidemiological and psychiatric aspects].
AB - OBJECTIVE: Despite the ongoing moral and legal debate, there is still a paucity
of empirical literature on the actual occurrence of Medical Decisions at the End
of Life (MDEL). Moreover, the psychiatrist's role in this scenario is still
unclear. METHODS: This paper systematically reviews currently available
literature on euthanasia (EU) and physician assisted suicide (PAS). Published
articles were selected if they reported either: 1) prevalence estimates of
patients' requests of EU/PAS; and/or 2) prevalence estimates of physicians'
actual EU/PAS practices. Papers exploring the issue of MDEL-related psychiatric
consultation have been also included in the review. RESULTS: The empirical
evidence reported in this paper shows that EU/PAS demands and acts are not
uncommon in medical practice. A conservative estimate indicates that at least 10%
of physicians have granted a request of EU/PAS. The involvement of consultation
liaison psychiatrists in MDELs seems to be relatively rare. CONCLUSIONS:
Euthanasia and other MDELs require physicians' thoughtful evaluation of criteria
guiding professional decision-making. To this purpose, epidemiological and
psychosocial research can offer a valuable contribution.
PMID- 9763766
TI - Patient-physician E-mail communication.
AB - A significant number of Oklahomans are using computers and have e-mail access
either at home or at work. Consecutive patients seen by 23 family physician
members of the Oklahoma Physicians Research/Resource Network (OKPRN) were queried
regarding their use of computers and access to e-mail. The numbers are higher in
urban and suburban areas than in medium and smaller towns and rural areas. Of
those who have e-mail access now or are planning to get it within six months, a
substantial majority would like to use this medium to interact with their family
physician. Potential uses for e-mail technology and problems to be overcome are
discussed.
PMID- 9763767
TI - A breach of trust: passing the wealth.
PMID- 9763768
TI - Marrow and stem cell transplantation in Oklahoma: fifteen years of experience and
results.
AB - From September 1982 to August 1997, 767 bone marrow or peripheral blood stem cell
transplants have been performed at the Health Sciences Center in Oklahoma. Five
hundred and two (502) autologous transplants (AutoTX) preceded by high-dose
myeloablative therapy were performed for breast cancer (BC, 36%), non-Hodgkin's
lymphomas (NHL, 24%), Hodgkin's disease (HD, 10%), acute myeloid leukemia (AML,
8%), testicular cancer (TC, 4%), multiple myeloma (MM, 2%) and other malignancies
(16%). Two hundred and sixty-five (265) allogeneic marrow transplants (AlloTX)
(related, unrelated) were carried out in chronic myeloid leukemia (CML, 30%), AML
(23%), acute lymphoid leukemia (ALL, 14%), myelodysplastic syndrome (MDS, 9%),
severe aplastic anemia (SAA, 8%), and other diseases (14%). Compared between
1980s to 1990s, 100-day mortality rates have decreased from 28% to 5% for AutoTX
and from 40% to 25% for AlloTX. In the AutoTX setting, major changes included the
routine use of growth factors post-transplant and the switch from bone marrow to
growth factor-mobilized peripheral blood as a source of stem cells over the last
five years. In the AlloTX setting, improvements in recognition and control of
cytomegalovirus and Candida organisms, the selective use of growth factors and
screened blood products, and better selection of unrelated donors using DNA-based
techniques of HLA-matching have contributed to reduce early mortality from
infection and primary graft failure. The five-year survival outcomes are
comparable to those reported in registry data from the International Bone Marrow
Transplant Registry (IBMTR) and the National Marrow Donor Program (NMDP).
PMID- 9763769
TI - De-mystifying social security disability adjudication: the physician's role.
PMID- 9763770
TI - The sick building syndrome: a danger to your health.
PMID- 9763771
TI - The state of the state's health. A report from the Oklahoma State Board of
Health.
PMID- 9763772
TI - The influence of affect on social-information processing.
AB - This study examined the impact of four affect induction conditions (self-induced
positive affect, music-induced positive affect, music-induced negative affect,
and neutral affect) on the social-information-processing skills of 96 seventh
grade students with and without learning disabilities using the Dodge (1983)
model of social skills. Following a 1-minute affect induction, students were
presented with a social problem and asked a series of questions that tested their
social skills. Although the results did not find significant differences between
school-identified students with and without learning disabilities, there were
significant main effects for language skills and affect induction. Students above
the median on the Iowa Test of Basic Skills language test generated more
solutions and fewer negative responses than students below the median. Students
in the self-induced positive affect condition generated more solutions, whereas
students in the music-induced positive affect condition generated more
embellishments and perceived less interpretation (negative/positive), than
students in the neutral and negative affect conditions. The implications of these
results for research and practice are discussed.
PMID- 9763773
TI - Social outcomes for students with and without learning disabilities in inclusive
classrooms.
AB - Social outcomes of students who participated in two different educational
settings designed to provide special services for students with learning
disabilities (LD) placed full-time within the general education classroom were
examined. Participants were 185 third-through sixth-grade students: 59 students
with LD, 72 low to average achieving, and 54 high achieving. There was an overall
educational setting effect, with students on the consultation/collaborative
teaching setting demonstrating more positive outcomes than students in the co
teaching setting on friendship quality and peer acceptance. Students with LD in
the consultation/collaborative teaching setting also demonstrated moderate
increases in the number of reciprocal friendships from fall to spring. Discussion
addresses the positive social outcomes for students with LD and high-achieving
students in the consultation/collaborative teaching setting, and the importance
of monitoring student progress in all settings.
PMID- 9763774
TI - Perceptions of academic strategies and competence in students with learning
disabilities.
AB - Research findings regarding general self-concept, academic self-concept, and self
awareness in students with learning disabilities have varied, and results are
still inconclusive regarding the consistency between students' and teachers'
judgments of academic performance. The current study focuses on students' and
teachers perceptions of the students' strategy use and performance in nine
different academic and organizational domains. Six hundred sixty-three students
and their 57 teachers were involved in the study. Findings indicated that the
students with learning disabilities considered themselves appropriately strategic
and competent in the five domains of reading, writing, spelling, math, and
organization. These students also rated their academic performance and
organization as average to above-average in seven of nine domains, with the
exception of checking and planning their work. Nevertheless, the self-ratings of
the students with learning disabilities were still significantly lower than the
self-ratings of average achievers in virtually all domains. The second major set
of findings revealed a sharp discrepancy between the self-assessments of the
students with learning disabilities and their teachers' judgments. Teachers rated
the students with learning disabilities as weak in their strategy use and below
average in their performance in all nine academic and organizational domains.
Finally, gender differences were not evident in eight of the nine domains. These
results have added to the increasing body of literature indicating that students
with learning disabilities frequently perceive themselves as capable and
effective and often rate themselves as academically stronger than their teachers
judge them to be.
PMID- 9763775
TI - Investigating reading disabilities using the rauding diagnostic system.
AB - Should a measure of intelligence be replaced by a measure of listening in
discrepancy definitions of reading disability? This question was answered using a
newly developed diagnostic system, which is based on "rauding" theory and a
causal model of reading achievement. In Study 1, diagnostic results were analyzed
from 122 students in Grades 3 through 7 who took, via computer, a battery of
tests called the computer Assisted Reading Diagnosis (CARD). In Study 2, 44
university students were given the CARD. In Study 3, the CARD was administered to
128 students in reading improvement classes at a suburban community college. From
the results, it was concluded that the rauding diagnostic system consistently
diagnoses disabilities in listening, decoding, and naming speed when they are
theoretically needed to explain accuracy and rate disabilities of children and
adults who are poor readers. It was recommended that (a) general intelligence,
fluid intelligence, or IQ not be used to measure potential or to diagnose reading
disabilities; (b) listening not be used to measure potential; (c) verbal
knowledge aptitude, pronunciation aptitude, and cognitive speed aptitude be used
to measure potential; and (d) the new rauding diagnostic system replace the
system of diagnosing dyslexics, hyperlexics, and garden-variety poor readers.
PMID- 9763776
TI - A validation of the role of preschool phonological and orthographic skills in the
prediction of reading.
AB - Two cohorts of children were followed to determine whether tests of phonological
awareness (Syllable Tapping), orthographic processing (Visual Matching), and
serial naming speed (RAN Objects), added to a preschool battery, would improve
prediction of reading. The major predictors of first-grade reading and spelling
were preschool letter naming and sentence memory for both cohorts, but the
orthographic and serial naming tasks added a small amount of additional variance.
Sentence memory accounted for the most variance in second-grade reading for both
cohorts, and Visual Matching made contributions to reading and spelling for each
cohort. Sentence memory, Visual Matching, and color naming together yielded an
87% to 90% hit rate in predicting which individual children would be good or poor
readers. The orthographic and serial naming speed tasks are useful additions to a
preschool predictive battery, but recommendations are that alternative preschool
phonological tasks, not based on syllable recognition, should be used to predict
reading.
PMID- 9763777
TI - The performance of students with disabilities in a norm-referenced, statewide
standardized testing program.
AB - Hawaii uses the Stanford Achievement Test, 8th Edition (Stanford 8), to assess
the academic performance of students in Grades 3, 6, 8, and 10. Three
longitudinal cohorts were analyzed for achievement performance among Grades 3 to
6, 6 to 8, and 8 to 10. ANOVAs indicated significant differences in overall
performance between nondisabled students and three high-incidence categories of
students with disabilities (specific learning disability, emotional impairment,
and mild mental retardation). Local subgroup norms were developed on the basis of
Stanford 8 reading and mathematics results from 1992 to 1996 to supplement the
national norms and provide an additional means of comparison to evaluate
performance for these categories. The longitudinal cohorts of students with
disabilities made greater gains in achievement from third to sixth grade than
their national counterparts and cohort of nondisabled students in Hawaii. Between
8th and 10th grade, students with learning disabilities and emotional impairments
made gains equal to or greater than their national counterparts'.
PMID- 9763779
TI - False starts and other dilemmas of a secondary general education collaborative
teacher: a case study.
AB - Currently, many special education policymakers, researchers, and practitioners
are questioning the efficacy of pull-out programs for students with disabilities
and advocating service delivery in inclusive or general education settings at
both the elementary and the secondary level. I investigated the implementation of
a collaborative teaching model in a suburban high school to determine how this
move toward inclusive education benefited teachers and students. Through
examination of the "ups and downs" of a U.S. History teacher, I concluded that
replicating and sustaining collaborative teaching can be difficult and complex
and, without careful consideration of contextual variables, may not lead to
improved outcomes for either teachers or students. Implications for research and
practice are discussed.
PMID- 9763778
TI - Cognition in children does not suffer from very low lead exposure.
AB - We studied the relationship between exposure to lead and memory and attention in
children. Participants were 313 boys aged 9 to 12 years who attended special
education schools in the Netherlands. Children whose possible attentional or
memory problems were obviously due to causes other than lead contamination were
excluded from the study. Cognition was assessed by extensive theory- based
testing. Blood lead concentration was measured to assess body lead burden.
Possible confounding factors that might affect blood lead level and/or cognitive
functioning were assessed. Blood lead levels were higher in children with lower
socioeconomic status and in children with more hand-to-mouth behavior, and varied
seasonally, with higher values in spring and summer. The mean blood lead level
was 44.4 microgram lead per liter blood, which is considered low. Only 2% of the
children showed a slightly higher blood lead level than the American safety
standard. To obtain robust measures of cognitive aspects, we performed a factor
analysis. The results showed that blood lead level did not influence any of the
cognitive factors. Therefore this study, despite being designed to maximize the
chance of finding an effect in asymptomatic children, does not support a
relationship between lead at very low doses (below 100 micrograms/liter blood)
and cognition in schoolchildren.
PMID- 9763780
TI - Why does my stomach hurt? How individuals with learning disabilities can use
cognitive strategies to reduce anxiety and stress at the college level.
PMID- 9763781
TI - Hearing voices, witnessing pain: in response to "why does my stomach hurt?".
PMID- 9763782
TI - [Function cerebral MRI].
PMID- 9763783
TI - [What is your diagnosis? A mass in the lateral ventricle].
PMID- 9763784
TI - [Intracranial dural arteriovenous fistula with perimedullary venous drainage].
AB - Two cases of intracranial dural arterio-venous fistula (DAVF) with perimedullary
venous drainage are reported. In both cases, MRI T2-weighted (T2W) images showed
an hypersignal within the cervical cord with sparing of the thoracic cord. In one
case perimedullary vessels were demonstrated on T1W images after gadolinium i.v.
administration. A complete spinal angiogram did not show evidence of fistula but
demonstrated the lack of opacification of the conus medullaris venous drainage.
Cerebral angiogram demonstrated in the first case a foramen magnum DAVF and in
the second case a petrous apex DAVF. Hypersignal limited to the cervical cord at
MRI on T2W images remain exceptionnal in case of intracranial DAVF with
perimedullary venous drainage. When neurological symptoms are suggestive, post
gadolinium T1W sequences should be conducted, followed by selective spinal
angiogram. If normal venous drainage is not objectivated (e.g. opacification of
radiculo-medullary veins on the late phase), cerebral angiogram should be done to
rule out an intracranial DAVF.
PMID- 9763786
TI - [Deep cerebral venous thrombosis].
AB - Deep cerebral venous system thrombosis is uncommon and is usually encountered in
children, generally in the neonatal period. In adults, this pathology is even
more exceptional. We report two cases in adults. Deep cerebral venous system
thrombosis mainly affects women taking oral contraception. The most common
clinical pattern combines headaches and confusion. A comatose state is rather
exceptional. This pathology, formerly considered to have poor prognosis, has
benefited from diagnostic and therapeutic progress. Favorable outcome has been
achieved in several recent cases, as one of ours, without after-effects.
Diagnosis, often suggested by the CT-scan, is based on MRI associated with MRA.
Thrombus formation is easily diagnosed by MRI at the subacute stage, but far less
easily at the acute and chronic stages as the low signal is identical to the
normal flow void. MRA, in phase contrast or time of flight sequences, is highly
interesting at the acute phase. In case of doubt, an angiography can be applied.
Therapy is based on heparin. The contribution of local infusion of thrombolytic
agents, recently used with success, remains to be determined.
PMID- 9763785
TI - Vasodilating in MR-angiography: a comparison of techniques.
AB - PURPOSE: To verify the hypothesis that a drug that causes vasodilation can
contribute to improvement in MRA spatial resolution. To test this hypothesis, a
comparison was made between the images obtained using the high resolution time-of
flight (TOF HR 3D) technique and the TOF 3D MTC TONE technique. METHODS: From
November 1993 to December 1994, we studied 40 patients, of which 20 patients (16
males and 4 females; average age of 10 years; range from 3 to 20 years) we
examined after they had inhaled Isoflurane (experimental group), and 20 patients
(16 males and 4 females; average age 9.7 years; range from 3 to 12 years) were
examined with standard MRA (control group). RESULTS: The vasodilator in both HR
MRA and MTC TONE MRA permits a better spatial visualization with respect to the
clinical routine MRA. On the other hand, it is true that MTC TONE gives better
visualization of the small vessels. DISCUSSION: In our experience, this
preliminary study indicates that with respect to routine MR, the spatial
resolution is notably increased when Isoflurane is used. The signal-to-noise
ratio is increased but, moreover, the ability to visualize small vessels is
increased. CONCLUSION: The preliminary results obtained in this study indicate
that a pharmacological drugs is capable of increasing the vascular detail of MRA
images of the intracranial vessels and that continued research this direction is
called for.
PMID- 9763787
TI - [Percutaneous vertebroplasty of the cervico-thoracic junction using an anterior
route. Technique and results. Report of nine cases].
AB - Percutaneous vertebroplasty using fluoroscopy is a well known technique.
Visualization of the posterior wall of the vertebra is mandatory. Good assessment
of this part of the vertebra is usually difficult at the cervico-thoracic
junction. We propose an original method to obtain adequate visualization of the
posterior wall, avoiding the shoulders superposition. Using this technique, we
performed twelve vertebroplasties in nine patients (one angioma and eleven
metastatic lesions). Clinical outcome was good for all patients, even a total
filling of the vertebra body by the cement was obtained in only eight cases on
twelve. No clinical complication was observed.
PMID- 9763789
TI - Cervical osseous changes associated with vertebral artery tortuosity.
AB - Vertebral artery tortuosity causing neural foraminal widening is a well described
abnormality that should not be confused with other causes of neural foraminal
enlargement, particularly on conventional roentgenograms. We, hereby, describe CT
features of another cervical osseous change due to the vertebral artery
tortuosity, the so called "tubular shaped vertebral artery canal", which is
embedded in the vertebral body instead of causing neural foramen enlargement.
Catheter and MR angiographic studies have also been performed to confirm the
vertebral artery tortuosity causing the osseous changes.
PMID- 9763788
TI - [Comparison of three fat suppression sequences for the detection of vertebral
detection. Turbo STIR, phase contrast gradient-echo, and MISTEC-Chopper after
gadolinium injection].
AB - OBJECTIVES: Assess three fat suppression sequences used to search for spinal
metastases: TurboSTIR, phase contrast gradient-echo, and MISTEC-Chopper after
gadolinium injection. MATERIAL AND METHODS: A prospective study was conducted in
10 patients with primary neoplasia. MIR sequences acquired (1 Tesla) were
TurboSTIR, T1 spin-echo with and without gadolinium injection, phase contrast
gradient-echo and M-Chop after gadolinium injection. Signal intensity in normal
bone marrow, metastatic tissue, and subcutaneous fat as well as background noise
was measured. Signal-to-noise (S/N) ratio was determined. Lesion borders,
artefacts, and extent of detected lesions were determined quantitatively. Bone
marrow signal intensity was also recorded. RESULTS: S/N ratio was best with
gradient-echo which identified well the borders of lesions within the hemopoietic
marrow. For lesions located in high-fat marrow (as in post-radiation marrow), the
high intensity signal of the lesion confounded with the fat signal. TurboSTIR
gave effective fat signal suppression and was particularly useful for yellow
marrow, less so for red marrow. This technique confounded cell proliferation with
perilesional edema (enlarging lesion extention). In one case, this sequence did
not detect a small lesion visible with the two other sequences. This sequence was
sensitive to artefacts (especially vascular artefacts) which can produce false
nodular images. M-Chop gave good suppression of vertebral fat tissue (better for
yellow marrow) but subjective detection of lesions was more difficult.
CONCLUSION: The phase contrast gradient-echo sequence after gadlinium injection
appeared to be the best sequence excepting cases of post-trauma (radiotherapy or
chemotherapy) fat transformation of the marrow where the TurboSTIR sequence could
be preferred.
PMID- 9763790
TI - [Hematomyelia complicating a spinal dural arteriovenous fistula. Report of a
case].
AB - We report a case of hematomyelia which led to sudden onset complete paraplegia in
a 74-year-old man. Hematomyelia revealed a spinal dural arteriovenous fistula at
level T8-T9. Spinal hemorrhage was observed in contact with a round-shaped
aneurysmal like ectasia which undoubtedly ruptured. Treatment was embolization.
Spinal atrophy followed and MRI one year after embolisation visualized the
involution of the pathological vessels. We discuss the pathophysiology of this
hemorrhagic accident and specific anomalies of the drainage veins in these
malformations.
PMID- 9763791
TI - Deep calcarine sulcus and prominent calcar avis.
AB - MR imaging examinations of the brain 100 consecutive patients, ages ranging from
1 year to 66 years, were evaluated in order to investigate the frequency of a
deep calcarine sulcus and prominent calcar avis. Twenty-four cases (24%) were
found with a deep calcarine sulcus and prominent calcar avis. These were
bilateral in four patients, and unilateral in twenty. Fifteen of the unilateral
cases demonstrated a right-sided involvement, and remaining five were left-sided.
A deep calcarine sulcus and prominent calcar avis should be distinguished from
disorders of neuronal migration and organization such as schizencephaly and
heterotopia. Also, based on our findings in this study, we speculate that it is
the deep calcarine sulcus and prominent calcar avis which creates the appearance
of the so-called accessory occipital ventricle.
PMID- 9763792
TI - [Current imaging of an "aberrant course" of the internal carotid artery].
AB - Blood flow via an aberrant internal carotid artery within the tympanic cavity is
a rare pathogenic embryonic variation causing pulsatile tintinus and a
vascularized tympanum. CT-scan provides the diagnosis. MRI and 3D time-of-flight
MRA appear ideal for exploring aberrant flow both for diagnostic purposes and to
establish the vascular morphology.
PMID- 9763793
TI - Schizencephaly and congenital cytomegalovirus infection.
AB - Congenital cytomegalovirus (CMV) infection is known to be associated with some of
the disorders of neuronal migration and organization, including gray matter
heterotopias, and polymicrogyria. We report a patient with schizencephaly and
congenital CMV infection.
PMID- 9763794
TI - Exercise, immune function and HIV infection.
AB - The implications of HIV infection for exercise and sport are reviewed. HIV
infection leads to impairment in a number of key elements of immune function,
most obviously a progressive decline in the numbers of CD4+ T helper/inducer
lymphocytes. Nevertheless, patients with early through moderately advanced HIV-1
infection can engage in moderate sport and exercise without risk to themselves or
other participants; the resulting gains of aerobic power and muscle strength are
similar to those observed in healthy individuals of comparable initial fitness.
In fully developed AIDS, the ability to exercise may be compromised by
deteriorations in cardiorespiratory and neuromuscular function. Given the
impairment of resting immune function, the potential immunosuppression from very
intensive bouts of competitive exercise must be avoided. Review of all published
papers to date provides a relatively limited data base. During a bout of moderate
physical activity, HIV seropositive individuals apparently have an impaired
ability to mobilize neutrophils, NK and LAK cells into the circulation.
Nevertheless, programmes of moderate training can be sustained without any large
change in CD4+ count or CD4+/CD8+ ratio. In some studies, training has also
attenuated psychological stress, possibly for this reason checking the
anticipated fall in CD4+ count. However, further large-scale randomized and long
term studies of HIV are needed, comparing the therapeutic value of exercise alone
with that of psychotherapy or a combined programme of exercise and psychotherapy.
PMID- 9763795
TI - Effects of intensive endurance exercise on DNA damage in leucocytes.
AB - OBJECTIVE: It has been shown that highly intensive anaerobic exercise induces DNA
damage in leucocytes (LEU). The present study was designed to investigate whether
intensive endurance exercise is capable of inducing comparable effects.
EXPERIMENTAL DESIGN: A prospective study. PARTICIPANTS: Twelve men (aged 27.3 +/-
4.1 years) who undertook a regular training of different extent (running volume
45 +/- 25 km.week-1) volunteered in the study. INTERVENTIONS: The subjects
competed in a half marathon (HM) of 21.1 km, 93.0 +/- 10.4 min. MEASUREMENTS:
Blood was taken at rest, 1 and 24 hrs after HM for determination of creatine
kinase, neutrophil (PMN), lymphocyte and monocyte counts. DNA damage in LEU at
rest and 24 hrs after HM was quantified using the single cell gel-electrophoresis
(SCG) assay. RESULTS: PMN increased from 2.81 +/- 0.69 to 13.13 +/- 2.91 1 hrs
after HM (p < 0.01) and returned to 3.26 +/- 0.47 10(9) cells.l-1 by 24 hr
recovery. DNA migration (image length, IL) reflecting the extent of DNA damage
was elevated significantly in 10 of 12 subjects one day after HM. IL rose from
32.7 +/- 2.2 to 40.7 +/- 3.9 microns (p < 0.01). Correlation analysis revealed a
relationship between DNA migration 24 hrs after HM and PMN count 1 hr post
exercise (r = 0.67, p < 0.05). CONCLUSIONS: The results confirm the hypothesis
that DNA damage in LEU occurs after intensive endurance exercise. We suppose our
observation of exercise-induced DNA damage in LEU is affected by reactive oxygen
species which are released from PMN. It is quite unclear whether DNA damage in
LEU is causal involved in exercise-induced modifications of the immune system.
PMID- 9763796
TI - Effect of lactate consumption on exercise performance.
AB - BACKGROUND: Maintenance of plasma glucose is important in endurance performance.
Gluconeogenesis or carbohydrate ingestion maintain glucose after hepatic glycogen
depletion. Lactate may also serve as a gluconeogenic precursor as well as a blood
buffer. METHODS: To determine if an 8% carbohydrate (CHO) sports drink with and
without a 2% lactate (L) solution increased endurance performance, peak power,
and delayed blood acidosis, seven trained cyclists participated in a double-blind
randomized study (6 males and 1 female) performed a bicycle test to determine max
VO2max HR and the HR associated with the first respiratory exchange ratio (RER)
value greater than 1.0 (target HR). Four bicycle rides to exhaustion, separated
by one week, were done at a constant workload at a HR 10 beats below each
subject's target HR. After a 12-hour fast, subjects received 100 g CHO 2-3 hrs
before each test. Mean exercise heart rate was 86-87% max HR. During the final 30
s of each ride the Wingate power test was performed. Subjects consumed either
(placebo, 2% L, 8% CHO or 8% CHO plus 2% L) every 20 min. Blood samples were
collected before, every 30 min during and immediately following the test.
RESULTS: No significant differences were observed in total time (placebo: 95.3 +/
25.8, 2% lactate: 95.7 +/- 30.0, 8% CHO: 105.2 +/- 37.2, 8% CHO + 2% lactate:
89.0 +/- 28.1 min) or peak power (placebo: 798.2 +/- 241.1, 2% L: 750.1 +/-
279.2, 8% CHO: 789.4 +/- 353.5, 8% CHO + 2% L: 716.3 +/- 331.3 Watts) among
drinks. There were no differences in insulin, glucose, pH and HCO3- after the
power tests among the drinks. CONCLUSION: Exercise performance is unaffected by
oral supplementation with lactate.
PMID- 9763797
TI - The effect of exercise intensity on the slow component of VO2 in persons of
different fitness levels.
AB - OBJECTIVES: To evaluate the slow component of VO2 in persons of different fitness
levels exercising at different intensities and the contribution of proposed
mediators to the slow component of VO2 using equations from the literature.
EXPERIMENTAL DESIGN: Cross-sectional. SETTING: University. PARTICIPANTS: Low (N =
15) and high (N = 15) fitness (VO2max of 37 vs 62 ml.min-1.kg-1). INTERVENTIONS:
None. MEASURES: Each subject completed, in random order, a series of 12 min cycle
ergometer exercise trials corresponding to 50, 60, 70 and 80% of VO2max. VO2,
minute ventilation (MV), blood lactate (BL), rectal temperature (RT), heart rate
and blood pressure were measured. RESULTS: There was a significant (p < 0.05)
increase in the slow component of VO2 for each level of fitness across time and
at each workrate. There were no between group differences for any variable. The
increase in the slow component of VO2 ranged from 70 ml.min-1 for the lighter
workrates to 543 ml.min-1 for the high fitness group at 80% of maximal VO2 (both
p < 0.05). The oxygen cost of MV, RT and rate pressure product accounted for
about 50% of the observed increase in the slow component of VO2. MV appears to
increase in a pattern most similar to the slow component of VO2 and the oxygen
cost of MV generally accounted for the highest percentage of the observed
increase. CONCLUSIONS: The slow component of VO2 needs to be considered when
prescribing exercise. These results are not conclusive concerning the primary
mediators of the slow component of VO2.
PMID- 9763798
TI - The Bruce treadmill protocol: does walking or running during the fourth stage
alter oxygen consumption values?
AB - OBJECTIVE: To investigate heart rate (HR) and relative oxygen consumption (VO2)
measures during two modes (walking or running stages four) of the Bruce treadmill
protocol. PARTICIPANTS: Male volunteers (n = 27), ranging in age from 25 to 56
years (M = 39.1 +/- 10.7 yrs). EXPERIMENTAL DESIGN: S's performed to volitional
fatigue on the two randomly assigned treadmill tests. MEASURES: HR and VO2 were
taken each minute and at point of exhaustion. RESULTS: Dependent "t"-tests
revealed a significantly (p < or = 0.05) difference between the protocols at 11
minutes (running = 46.7 +/- 3.9 > walking = 44.6 +/- 3.7 ml[kg.min-1]) and at 12
minutes (running = 49.3 +/- 4.1 > walking = 47.6 +/- 3.5 ml[kg.min-1]) on the VO2
values. A significant differences was noted on HR at 11 minutes (running = 158.1
+/- 13.5 > walking = 156.0 +/- 13.0 bpm) and at 12 minutes (running = 160.4 +/-
11.0 > walking = 157.8 +/- 11.4 bpm) between the protocols. The two-way ANOVA
technique revealed no significant differences or interactions on VO2 or HR
between younger (< 45 yrs) and older (> or = 45 yrs) subjects during either
protocol. A one-way ANCOVA indicated no significant differences between taller
and shorter subjects on VO2 during the fourth stage of the Bruce protocol. The
correlations, between the two protocols, for HR were strong but were weaker and
inconsistent for VO2. The repeated measures ANOVA indicated significant within
subject variability between test administrations. CONCLUSIONS: When testing
endurance trained males, modality, age and height are not factors in differences
of VO2 values during the 4th stage of the Bruce treadmill test but learning
effect could be.
PMID- 9763799
TI - Basal reproductive hormonal profiles are altered in endurance trained men.
AB - OBJECTIVE: The purpose was to examine the basal reproductive hormonal profiles in
age-matched groups of endurance trained (ET) and sedentary (SED) men under
controlled conditions. EXPERIMENTAL DESIGN: Resting basal blood samples were
obtained from groups of ET and SED men after a 24-hr control period. Blood
specimens were analyzed for testosterone (T), free-testosterone (fT), sex-hormone
binding globulin (SHBG), luteinizing hormone (LH), cortisol, and prolactin. The
design of the study was retrospective and cross-sectional in nature. SETTING:
Laboratory setting at the University of North Carolina, North Carolina USA.
PARTICIPANTS: ET men (n = 53) who had been involved with chronic endurance
exercise training for > or = 5 years. SED men (n = 35) were selected of
comparable ages and the fact that they had done no formal exercise training.
RESULTS: Results indicated that the basal T and fT of the ET men were
significantly (p < 0.01) lower than that of the SED men. The levels of these
hormones in the ET men where in the normal clinical range, but represented only
55% to 85% of those seen in the SED men. For SHBG, LH, cortisol, and prolactin,
no significant differences (p > 0.05) were found between the ET and SED men.
CONCLUSIONS: ET men have lowered basal T and fT levels and this suppression may
be related to an alteration in the hypothalamic-pituitary-testicular regulatory
axis since the LH of the ET was not elevated. Whether these hormonal changes have
any significant beneficial (i.e., protective cardiovascular) or negative (i.e.,
decrease anabolic-androgenic processes) physiologic consequences remains to be
determined.
PMID- 9763800
TI - Alcohol use and behaviors in women long-distance race participants reporting a
history of bulimia and/or anorexia nervosa.
AB - OBJECTIVE: To describe the relationship between a reported a history of an eating
disorder, a history of problem alcohol behavior and current alcohol consumption
in women long-distance runners. DESIGN: Survey. SETTING: General community.
PARTICIPANTS: Women participating in a 20-mile road race (n = 398) and age
matched non-exercising women enrolled in a family practice health maintenance
organization (n = 121) (mean age, 37.1 +/- 9.4 years). INTERVENTION: Not
applicable. MEASURES: Responses to questions relating to 1) a past history of an
eating disorder; 2) weight; 3) running and exercise habits; 4) drinking behaviors
using alcoholism screening tests; 5) quantity-frequency data of the previous two
week alcohol consumption. RESULTS: Ten percent of racers and 4.1% of controls
reported a history of an eating disorder. Those racers reporting a history of
bulimia nervosa without anorexia were more likely to report feeling guilty about
their drinking, drunk-driving arrests, an elevated score on an alcoholism
screening test (suggestive of problem drinking), alcoholism, and seeking help for
problem drinking than other racers or the control population without a history of
an eating disorder. However, bulimic racers did not report either increased
current alcohol consumption or occasions of drinking, including binge drinking
(five or more drinks in one episode). CONCLUSIONS: Women racers reporting a
history of bulimia nervosa are more likely to report a history of problem
behaviors with alcohol but not differences in current alcohol consumptions from
that reported by other women racers or women without a history of an eating
disorder from the control population.
PMID- 9763801
TI - Cardiovascular fitness, physical activity and selected coronary heart disease
risk factors in adults.
AB - BACKGROUND: The aim was to investigate the associations between cardiovascular
fitness and physical activity, and their relationship to selected coronary heart
disease (CHD) risk factors. METHODS: This was a cross-sectional study for one
week. All participants were Japanese living in the City of Toyota, Japan. Two
hundred and twenty-two healthy Japanese (104 men and 118 women), with ages
between 20 and 62 years old. Cardiovascular fitness (VO2max) was measured by a
progressive submaximal bicycle ergometry test. Physical activity was estimated by
an accelerometers attached to the subject's waist for one week, CHD risk factors
included blood pressure, fasting levels of blood lipids, and apolipoprotein
concentrations. RESULTS: Cardiovascular fitness and physical activity were
positively related (r = 0.41 in men and 0.65 in women). For both genders, Pearson
coefficients as well as age-adjusted partial correlations indicated that fitness
was more closely linked to CHD risk factors than activity was. Also, CHD risk
factors were analyzed by three groups of fitness and activity levels in both
genders, which indicates that subjects who are physically fitter and/or more
active tend to have better CHD risk profiles. CONCLUSIONS: As favorable CHD risk
profile was related to cardiovascular fitness, but not to physical activity in
both genders, it can be concluded that fitness may be a more important
independent predictor for CHD risk factors than activity measured by
accelerometer over one week.
PMID- 9763802
TI - Prolonged exercise alters cardiac chronotropic responsiveness in endurance
athletes.
AB - OBJECTIVE: To determine whether exhaustive exercise alters cardiac adrenergic
chronotropic responsiveness in endurance-trained athletes. METHODS: Fifteen
athletes were studied prospectively 2-4 days before and within 3.3 hours after
completing the Hawaii Ironman Triathlon (3.9 km swim, 180.2 km bike, 24.2 km
run). Increasing intravenous boluses of isoproterenol were given until the rise
in heart rate was > 30 bpm (n = 3-6 doses). A log dose heart rate response curve
was constructed, and the dose required to increase heart rate by 15 and 25 bpm
estimated. Left ventricular size and function were also assessed by
echocardiography. RESULTS: After race finish, left ventricular volume (98 vs 83
cc), ejection fraction (56 vs 46%) and diastolic filling (3.86 vs 3.12 edv/sec)
were reduced (all p < 0.01). Resting heart rate rose from 54 +/- 7 bpm to 70 +/-
10 bpm. The isoproterenol dose required to increase heart rate by 15 bpm rose
from 0.6 to 1.7 micrograms by 25 bpm rose from 1.8 to 4.0 micrograms, both p <
0.01. The linear relationship between change in heart rate and log isoproterenol
dose was preserved. CONCLUSIONS: Cardiac chronotropic responsiveness is reduced
following an Ironman triathlon.
PMID- 9763803
TI - The electrocardiographic T wave changes in highly trained athletes during
training. An old problem revisited.
AB - OBJECTIVE: To evaluate the T-wave pattern alterations during vigorous training in
elite athletes. SETTING: Institute of Sport Science in Rome and National Rowing
Center in Piediluco, Italy. STUDY POPULATION: Nine male and 7 female rowers of
the national team were examined prospectively at different times of their
conditioning period. METHODS: All athletes underwent electrocardiography and
echocardiography; the ecg was analyzed for QRS voltages and axis, T-wave pattern
and QTc interval; from echocardiography the left ventricular (LV) cavity
dimension, wall thickness and mass were calculated. From Doppler-echocardiography
the transmitral diastolic LV filling pattern was evaluated. RESULTS: Variation of
T-wave voltages was seen in all the athletes. Specifically, during the low
intensity training period the T-wave pattern was positive and increased in
voltage (T-wave max amplitude in V6 increased to 130% in male and 100% in female
than pretraining values). During the peak training a variety of patterns was
observed, and a transient flattening was present in 50% of subjects. No
concomitant alteration of heart rate, QRS and T-wave axis and QTc duration were
observed. No significant changes of cavity dimension, wall thickness, LV mass
index and Doppler-derived diastolic peak flow velocities were detected during the
study period. CONCLUSIONS: Transient changes of T-wave pattern may occur in
athletes as an effect of athletic conditioning, without changes of cardiac
dimension or alteration of indexes of LV function. This finding supports the role
of ecg monitoring to follow-up the individual athletes response to training
exercise load.
PMID- 9763804
TI - Reliability of isokinetic knee extension and flexion strength testing in elderly
women.
AB - BACKGROUND: Intertrial and test-retest reliability of isokinetic knee extension
and flexion strength measurements was studied in eighteen elderly women (mean age
68 +/- 5 yrs), using increasing and decreasing angular velocity testing
procedures. METHODS: EXPERIMENTAL DESIGN: five reciprocal knee extensions and
flexions at three different angular velocities (90, 120, and 180 deg/sec) were
performed by means of a MERAC apparatus on two occasions fifteen days apart.
MEASURES: Data relative to torque, power and work were considered. RESULTS:
Statistically significant differences were found often among the five trials and
intraclass correlation coefficients, ranging from 0.03 to 0.90 for extensor
muscles; ranging from 0.44 to 0.89 for flexor muscles, were shown among the best
three outputs. Peak values were reached within the first three repetitions,
though a 20% chance to produce peak outputs was shown in the last two
repetitions. Increasing and decreasing test velocity procedures did not
consistently show statistically significance for peak outputs. Generally, for
each isokinetic parameter higher and more frequently significant correlation
coefficients between test and retest experimental sessions were found for peak
values (ranging from 0.36 to 0.80) with respect to mean values (ranging from 0.22
to 0.74). CONCLUSIONS: These data suggest that a test procedure including five
trials tends to increase the chance of producing the best peak outputs.
Furthermore, considering the best peak and mean performances could be more
appropriate when studying elderly women.
PMID- 9763805
TI - Recurrent rhabdomyolysis associated with influenza-like illness in a weight
lifter.
AB - OBJECTIVE: This report describes a unique case of recurring rhabdomyolysis
associated with influenza-like illness. PATIENT: A 16-year-old black male, a
physically fit weight-lifter, presented complaining of a brief history of upper
respiratory infection. He had experienced muscular aches and observed his urine
was a brown "Coca Cola" color. He was diagnosed with an influenza-like illness
and associated rhabdomyolysis. He had been previously treated for a similar
episode of flu-like symptoms and brown urine two years before. The patient was
treated with IV fluids and discharged on day seven. He has remained asymptomatic.
Post-discharge muscle biopsy results indicated a partial deficiency of carnitine
palmitoyltransferase II, a rare defect in mitochondrial metabolism. DISCUSSION:
Although traumatic rhabdomyolysis cases have been reported, few case reports have
been documented associating an influenza-like illness and rhabdomyolysis.
Deficiency of carnitine palmitoyltransferase often causes nonexercise-induced
rhabdomyolysis. CONCLUSION: Prevention should consist and a yearly influenza
vaccination education on nutrition and exercise.
PMID- 9763806
TI - [Neuroleptanalgesia in patients undergoing percutaneous, ultrasound-directed
radiofrequency for primary or secondary, single or multiple hepatic neoplasms].
AB - BACKGROUND: The use of percutaneous ultrasound-directed radiofrequency is a
recent technique in non-surgical therapy of some neoplastic liver lesions.
Purpose of this study is to demonstrate that the use of a narcosis-free analgesia
allows to perform this procedure, which is generally painful and badly by the
patient. METHODS: We treated 51 patients for a total of 126 procedures; the first
17 patients underwent a mono- or multipolar technique with uncooled electrodes,
while the remaining 34 patients have been treated with double perfusion lumen
electrodes with the chance of tipcooling. We used diidrobenzoperydol and fentanyl
with a mean dose for each session of 209 micrograms for the first 17 patients and
109 micrograms for the other 34. RESULTS: Using VAS, we obtained a painless
procedure in 42 patients and mild-pain sensations in 9 patients, while one hour
after the procedure painless or light-pain sensation were observed in 49 patients
and mild-pain in 2 patients, which required the use of FANS i.v. At discharge,
all patients were pain-free or with very light pain sensation. We reduced the
intra-hospital observation of patients from 5 to 3 hours, once the technique has
been modified. 4 patients complained about nausea and 1 of these emesis. We did
not observe any cardiovascular, respiratory and/or neurological complications.
CONCLUSIONS: The use of neuroleptanalgesia allowed us to perform the described
procedure with a good feeling by the patients.
PMID- 9763807
TI - [Mathematical model for the predictive value of a test in critically ill patients
studies according to APACHE II score and pathology at admission].
AB - OBJECTIVE: To find a predictive model for mortality at four different days from
the admission for critically ill patients. DESIGN: Retrospective study on two
consecutive series of critically ill patients admitted in ICU. SUBJECTS: 1254
critically ill patients, subdivided into two series of 813 (561 survivors and 252
non survivors) and 441 patients (291 survivors and 150 non survivors),
respectively. INTERVENTIONS: None. MEASUREMENTS: All patients had APACHE II
calculated within the first 24 hours from the admission in ICU and, if the
patient was still in ICU, also at the 5th, 10th and 15th day from the admission.
Casistics was subdivided into two unequal series, ratio 2:1, with a random
selection made on each of the 6 considered years. On the 1st series, in 1st, 5th,
10th and 15th day, for mathematical predictive models were made, using stepwise
logistic regression (BMDP, Los Angeles). In the 1st day the following independent
variables were utilized: APACHE II score, the specific diagnosis at admission,
fitted following Knaus' diagnostic criteria, united in 6 principal categories,
while for the other 3 days the variation % of APACE II score as regards the
previous day. RESULTS: For each of the considered day four mathematical models
have been made. These models have been validated in both series in calibration
from the Hosmer-Lemeshow Goodness-of-fit test and in discrimination from the ROC
curves. For each day Y (Prob.% to die) = eLogit/1 + eLogit, where Logit = beta 0
(constant) + beta 1*APACHE II + beta 2*Variat.%APACE II (difference between
actual APACHE II - APACHE II of the previous day/actual APACHE II) + beta k,
(coefficient pertinent to pathology). CONCLUSIONS: The mathematical model, as
other models do, stratifies enough the casistics according to the risk of death.
Waiting for further studies to make more precise prognostic mathematical models,
this one and others can help the clinical assessment in single patient
evaluation.
PMID- 9763808
TI - [Morphologic and biochemical kinetics of the pathogenesis of acute lung injury by
endotoxin in rats].
AB - BACKGROUND AND AIM: To highlight the intervention sequence of cells and their
products (RO degree and NO) involved in the pathogenesis of lung injury caused by
the instillation of endotoxin in rats. EXPERIMENTAL DESIGN: An experimental
comparative study in rats. MATERIALS AND METHODS: The experiments were performed
using intratracheal instillation of endotoxin in rats (5 mg/kg in 0.125 ml of
saline solution). Untreated rats or those instilled with saline solution alone
formed the control group. All animals were sacrificed 12, 24 and 48 hours after
instillation and the following studies were performed on both lungs: 1)
morphological study (optical and electronic); 2) assay of lung MDA; 3) NADPH
diaphorase evaluation using a histochemical method. RESULTS: Lung damage evolves
gradually over 48 hours. After the first 12 hours, neutrophil granulocytes were
present in the lung capillaries together with monocytes; monocytes were also
present in the interstitium. During the following hours, monocytes differentiated
into macrophages and, once activated, the granulocytes passed into the
interstitium. The parenchyma appears to be extensively altered. Tissular MDA
gradually increases until it reaches a maximum level (p < 0.01 vs basal) at 48
hours. Positivity for NADPH-d in macrophage and/or fibroblastic cells was evident
after 24 hours and increased after 48 hours. CONCLUSIONS: Acute lung injury
caused by endotoxin involves both NO and RO degree. Their production is related
to different cell types and follows slightly different kinetic.
PMID- 9763809
TI - [The effects of a dose of epidural clonidine combined with intrathecal morphine
for postoperative analgesia].
AB - OBJECTIVE: To evaluate the effectiveness of a single bolus of epidural (ED)
clonidine (C) associated with intrathecal morphine (M) on postoperative analgesia
after cesarean section (CS). DESIGN: Prospective double-blind randomized study.
SETTING: Obstetric department. PATIENTS: Fourty patients ASA 1-2 submitted to
combined spinal-epidural block (CSE) for CS. INTERVENTIONS: A needle through
needle set for CSE was used. The intrathecal block was induced with 2.7-3 ml of
isobaric 0.5% bupivacaine (B) and 250 micrograms of M. After ED test with 0.5% B,
a single bolus of C 150 micrograms in NS 10 ml (group C, n 20) or NS 10 ml as
placebo (group P, n 20) was given through the ED catheter. METHODS: The
observation for 36 hours evaluated analgesia (VAS until the first dose of
additional analgesic, total amount of analgesic and time of first analgesic
request) and side effects (variations of arterial pressure and heart rate, motor
block, sedation, nausea, vomiting, itching, respiratory depression). Groups were
statistically compared. RESULTS: In group C lower analgesic request
(significantly between 12th and 18th hour) and significant delay of first request
(22.5 +/- 4.1 h) were registered. VAS showed significant trend to opposite sign
variations (downwards in group C, upwards in group P) at 1, 2 and 12 hours. In
group C lower sistolic arterial pressure at 1 and 4 hours, denser motor block at
2 and 4 hours and mild sedation were observed. CONCLUSIONS: A single ED bolus of
C 150 micrograms after CS significantly enhances and prolongs the analgesic
effect of M 250 micrograms without important side effects.
PMID- 9763810
TI - Inhaled nitric oxide during anesthesia for bilateral single lung transplantation.
Case report.
AB - Recently inhaled nitric oxide (iNO) has been used as pulmonary vasodilator
without any effect on systemic hemodynamics. iNO has been also used in cardiac
and thoracic surgery, involving lung transplantation. In this case report a
patient, 41 years old female, affected by bronchiectasis, underwent bilateral
sequential single lung transplantation and during one lung ventilation and
pulmonary artery clamped iNO allowed to avoid cardiopulmonary bypass and to carry
out the procedure successfully.
PMID- 9763811
TI - Unexpected cardiac arrest during epidural anaesthesia.
AB - We reported the case of sudden asystole requiring close chest cardiac massage in
a 56-yrs-old health man receiving epidural anaesthesia for elective transurethral
resection of bladder tumour (TURBT). The anaesthetic procedure was performed in a
regional-block-room. Cardiac arrest developed few minutes after local anaesthetic
injection, before the patient has been transferred to the operating room. The
importance of patient monitoring during regional anaesthesia must be further on
pointed out, especially when the anaesthetic procedure is performed out of the
operating room (e.g. in the recovery room or in a "regional-block-room").
PMID- 9763812
TI - [Prevention of obstetrical damage to the perineum. Proposal for a fetal-pelvic
index for the selection of parturients at risk].
AB - BACKGROUND: According to some authors, vaginal delivery always causes denervation
of perineum and the greater the damage the longer the second labour phase (the so
called "delivering phase"). Therefore, it is necessary to reduce the number of
too prolonged labours, but it is equally important to avoid an uncontrolled
increase of cesarean sections. In order to achieve this objective, it is
important to carry out a careful selection among laboring women and choose those
most at risk for whom cesarean section is strongly recommended. On the basis of
the data collected by the medical literature and in consideration of the
pathogenetic role of the outlet dystocia, we have tried to identify a simple and
effective prognostic index resulting from the different pelvimetric and
ultrasonographic parameters. METHODS: In 72 full-term pregnant women, we have
taken into account the ultrasonographic parameters expressing the fetal dimension
(cephalic diameters, cephalic and abdominal circumferences, estimated fetal
weight according to Haddlok), the outlet pelvic diameters (trans-ischial and
coccygeal-pubic) and a fetal-pelvic index derived from these parameters. RESULTS:
If taken individually, these parameters do not seem to have any direct connection
with the length of the delivering phase, but the combination of the cephalic and
external pelvimetric diameters has produced a significative statistical
coefficient. CONCLUSIONS: On the basis of the data collected, it is suggested
that a careful evaluation of external pelvimetric and cephalic parameters would
be useful from the clinical point of view.
PMID- 9763813
TI - [Predictive factors of fetal macrosomia].
AB - BACKGROUND: Fetal macrosomia is a condition which may increase the risk of
mechanical and/or dynamic problems for the parturient. In the past, we have
demonstrated that in more than half of the cases it is not possible to exclude a
contribution of maternal pathology to the determination of fetal-macrosomia. The
aim of this work is to verify whether our more recent experience regarding
predictive factors of fetal macrosomia shows some noteworthy novelty. METHODS:
The study was retrospectively carried out on pregnant women who, during the
period January 1994-February 1996, delivered babies weighing at least 4 kg at the
Midwifery School of Camerino. With regard to the frequency of the main risk
factors of fetal macrosomia described in scientific literature, the sample was
compared with a control group randomly selected. RESULTS: Advanced gestational
age at the time of delivery, parental tallness, maternal overweight/obesity,
gestational glucidic dysmetabolism, a distance between pubis and uterine fundus
of at least 34 cm, male sex of the unborn child have proved to be predictive
factors of fetal macrosomia. CONCLUSIONS: The differences in comparison with the
past, on the other hand altogether negligible, are the consequence of changes in
the management of some obstetric situations.
PMID- 9763814
TI - [Use of intrauterine device by nulliparous women. Prospective study and
preliminary data].
AB - BACKGROUND: The aim of the study, that is still on the way, was to evaluate the
negative effects of an intrauterine device, used for more than 2 years, on future
fertility of young women who due to medical or personal reasons couldn't use
hormonal contraceptives. METHODS: A prospective study was started in 1987 in a
group of 515 nulliparous healthy women (age 20-30) using an intrauterine device
(Nova T, Schering, Multiload Cu 275 Organon) as contraceptive method. Two hundred
and twentyfour women wished to become pregnant following the IUD extraction.
RESULTS: Within 12 months, 221 (98.7%) of them became pregnant demonstrating the
harmlessness of the contraceptive method on future fertility. All pregnancies had
a normal course, except one abortion at the 8th week of gestational age. There
hadn't been pregnancies during the observation period, 25 (4.8%) women requested
the IUD be removed before the end of the study because of side effects.
DISCUSSION: IUD did not cause a reduction in fertility or an increase in ectopic
pregnancy in our group of patient.
PMID- 9763815
TI - [Psychological consequences in women with symptomatic HPV infection].
AB - OBJECTIVE: Evaluation of psychological and social aspects of women with diagnosed
genital HPV-infection. EXPERIMENTAL DESIGN: A retrospective study of 40 women
with a diagnosis of HPV-genital infection has been made. INTERVENTIONS AND
MEASURES: A questionnaire for gathering information on social life, sexuality and
emotional relationship with the partner was submitted to the patients. RESULTS:
There is a high percentage of sexual impairments after diagnosis of HPV
infection. CONCLUSIONS: HPV infections, as many genital pathologies, lead to
problems with sexuality as well as hypochondriac fears.
PMID- 9763816
TI - [The ICSI (Intracytoplasmic Sperm Injection)].
AB - ICSI (Intracytoplasmic Sperm Injection) is the latest known assisted reproduction
technique (ART) and it already appears to be mature. In fact the analysis of the
results presented by the researchers over the years has shown that the most
specific indication for this ART is the sterility of the couple with serious male
pathology, up to ejaculatory azoospermia where it is possible to perform MESA,
PESA or TESE. Any kind of sterility could be solved with ICSI whose only limit
presently known is the high technology and therefore high costs involved. The
percentage of oocytes that undergo ICSI without being damaged varies from 87% to
94% and the percentage of fertilization varies from 33% to 71%. The transfer rate
is 59-100%. The rate of pregnancies per couple ranges from 12% to 40% of the
couples, from 11% to 41% for the transfers. Since abortions are similar to the
values of the normal population (10-15%), ICSI is actually the assisted
fertilization technique with the highest incidence of pregnancies and "take home
babies". The percentage incidence of the two sexes, of the malformations and the
typologies of malformations corresponds to those observed in the population with
spontaneous pregnancies. Since there is no natural selection of the gametes in
ICSI, one may be sure that when spermatozoa with any kind of pathology are
injected, the pregnancy does not take place at all.
PMID- 9763817
TI - [Hereditary renal agenesis . Report of a case].
AB - Renal agenesis is thought to result from a lack of induction of the metanephric
blastema by the ureteral bud. Bilateral renal agenesis/dysgenesis (BRA/D) is
rare, occurring in only one or two per 10,000 births. Despite its being moreover
a sporadic event, there is a male to female ratio of 2.5 to 1 and approximately
20-36% of BRA/D present a familial recurrence, for genetic transmission most
probably autosomal dominant with incomplete penetrance and variable expression,
termed hereditary renal adysplasia (HRA). A case of prenatal diagnosis by
ultrasound of renal agenesis/dysgenesis (left renal agenesis and severe right
multicystic dysplastic kidney) is described here. A woman in the 32nd week of
pregnancy, who has never undergone any clinical and medical examination, presents
at the ultrasound control. A male fetus was born from breech delivery at 34 weeks
gestation, weighted 1950 g died after two hours because of severe pulmonary
hypoplasia. Autopsy confirmed the antenatal diagnosis of left renal agenesis and
right multicystic dysplastic kidney, that measured 42 x 31 x 25 mm, with
bilateral complete absence of ureters and renal vessels. No other malformations
were present. The infant's chromosomes were normal (46 XY). No specific
chromosomal anomaly was identified in either parents. Both the parents had normal
genitourinary ultrasound findings. In the wife's family pedigree, a sibling had
asymptomatic unilateral renal agenesis, found at ultrasonography, and one
maternal aunt had unilateral multicystic kidney and bicornuate uterus. Moreover
one maternal uncle died at birth after preterm delivery from respiratory failure,
unfortunately kidneys were never examined. Instead, no renal anomaly was
identified in the husband's family history. The parents must be made aware not
only of the inevitable fatal outcome for the fetus but also of the increased risk
of recurrence in a subsequent pregnancy. On the basis of the literature, (of
which this case is a further confirmation) it is underlined the necessity that
all families of bilateral renal agenesis/dysgenesis patients-should have a
detailed evaluation, including a detailed family history and ultrasound study of
the kidneys and uterus; in fact all first-degree relatives have an increased risk
of having silent genitourinary malformations.
PMID- 9763818
TI - [The role of chorionic gonadotropin in transient hyperthyroidism in hyperemesis
gravidarum].
AB - A possible association of hyperemesis gravidarum with biochemical transient
hyperthyroidism (a significant self-limited increase in serum levels of some
thyroid hormones) has long been reported. It seems there is not any causal
connection between the two above mentioned conditions, but they may be both
independently related to the same cause: the trophoblastic production of a large
amount of human chorionic gonadotropin or, otherwise, the presence in the
maternal circulation of structural variants of hCG with higher biological
activity. The validity of such hypothesis, denied by some authors, encounters the
verification in the peculiar clinical case described in this report. It also
shows clearly the danger of considering a case of hyperemesis gravidarum as of
psychological nature, without having preliminarily excluded an organic cause. For
the pregnant woman, to hear of her unconscious refusal of pregnancy or of the
timeliness of her removal from the environment in which some conflictual
situations have likely raised or, furthermore, to hear of other common places
often too easily evoked could be cause of anxiety and unjustified feelings of
guilt.
PMID- 9763819
TI - [The role of vaginal pH. Importance of its normalization in the prevention of
recurrent vaginitis].
AB - BACKGROUND: A sample of 100 women was clinically examined for a very various
vulvovaginal symptomatology and an individual diagnosis of vulvovaginitis of
different aetiology was established. METHODS: All women were treated with
antibiotic and/or antimycotic drugs on the basis of individual diagnosis. Sixty
women had only this treatment, while 40 women had also a supplementary treatment
with a cleanser emulsion characterized by physiologic pH value and an antiseptic
activity due to a vegetable extract (Saugella Attiva, Lab. Guieu). The
symptomatologic changes due to the two treatments were compared. RESULTS AND
CONCLUSIONS: Combined treatment (drug + antiseptic) obtained better results
mostly in subjective symptomatology; this combined treatment was very useful in
the recovery of the Doderlein population.
PMID- 9763820
TI - [Pregnancy today. Randomized study of the emotional state of the woman and her
partner].
AB - BACKGROUND: Pregnancy is a remarkable ground for studying the biopsychosocial
perspective of psychosomatics, because there is a close correlation between
biological conditions, that quickly change in time, and emotional implications
that are this result of women psychological structure, her psychosexual
maturation degree and her social and environment past and present influences.
METHODS: Through a questionnaire including some general data and a more specific
section to evaluate psychic and emotional factors of the pregnant and her partner
during pregnancy, we interviewed 100 pregnant women beginning from the 32nd
pregnancy week; all women attended the psychoprophylactic lessons for childbirth,
they were between 20 and 41 years old and the 87% was primipara and the 13% was
multipara. RESULTS AND CONCLUSIONS: This study showed that even if pregnancy is
more and more planned and desired, anxiety and fears follow the joy and the
happiness of having child, both in man and in woman. Thus, pregnancy and birth,
seem to be, also today, too much medicated to the detriment of the "naturalness"
of the event: in fact, woman uptake more drugs and there is an increased need to
have a good medical assistance not for real obstetrical problems but only to make
up for intense anxiety.
PMID- 9763821
TI - Collective bargaining is inevitable for physicians.
PMID- 9763822
TI - 1998 statutory changes affecting controlled substances.
PMID- 9763823
TI - Emergency medicine quiz.
PMID- 9763824
TI - Case report of long-term survival in a patient with acquired immunodeficiency
syndrome and cryptococcal meningitis.
AB - In the era before protease inhibitors were available, the great majority of
patients with AIDS died within five years of the diagnosis. This grim reputation
may cause both physician and patient to give up hope prematurely when
antiretroviral therapy fails. We report a patient who survived five years after
the diagnosis of cryptococcal meningitis and AIDS. Although there are now
combinations of antiretroviral drugs available that can delay disease progression
and extend the lives of AIDS patients, these are associated with a significant
failure rate. It is thus important to be aware of the potential to extend life in
patients even when antiretroviral therapy is not effective.
PMID- 9763825
TI - [A painful inflammation of the thyroid].
AB - Four women aged 30, 29, 52 and 43 years presented with what appeared to be
subacute thyroiditis (De Quervain's thyroiditis). This disease is characterized
by fatigue, a painful thyroid gland and thyrotoxic manifestations. The diagnosis
is further based on a high erythrocyte sedimentation rate and low tracer uptake
during thyroid scintigraphy. Only the first patient showed a typical course. In
the second and third ones the painful thyroid was associated with nodular
enlargement. Fine needle aspiration cytology was at first consistent with
subacute thyroiditis but a repeated aspiration showed papillary carcinoma in the
second and anaplastic carcinoma in the third patient. In the fourth one, subacute
thyroiditis was accompanied by normochromic anaemia, a low serum albumin
concentration and liver function disorders. She made a full recovery without
treatment. Thyroid malignancies can mimic subacute thyroiditis. Persistent
nodular enlargement of the thyroid is suspicious and requires careful
investigation.
PMID- 9763826
TI - [Appearances deceive in investigations of cancer clusters].
AB - Many a doctor from time to time encounters people concerned about environmental
causes of disease, whom he or she cannot answer properly because of lack of
knowledge concerning the effects of chemical or physical exposure of the human
body (nuclear plants, environmental pollution, electromagnetic radiation).
Usually post hoc cluster investigation is very unrewarding especially when there
is no clearcut hypothesis or evidence of a causal relation, and when the relative
risk is well below 8. From an epidemiological point of view it is surprising that
an unexpectedly low frequency of a certain disease in a particular region does
not attract this kind of attention. Concerned people will most probably benefit
more from risk communication by environmental epidemiologists than from cluster
investigation or extensive case-control studies ('fishing expeditions') in case
little is known of the etiology.
PMID- 9763827
TI - [Health Council Report 'Radiofrequency electromagnetic fields (300 Hz-300 GHz).
The Health Council of the Netherlands].
AB - The Health Council of the Netherlands in 1997 issued a report updating the
guidelines for maximum acceptable exposure to radiofrequency electromagnetic
fields formulated in 1975. The new recommendations are based on thermal effects
for frequencies over 10 MHz. The committee considers the results of studies
indicating non-thermal effects such as direct damage to DNA, not reliable enough
to be used in setting exposure limits. Electromagnetic interference by
electromagnetic fields generated by hand-held telephones may indirectly result in
threats to health if vital medical equipment is affected. The committee advises
people wearing an implanted pacemaker not to carry a portable telephone that is
in stand-by mode in close proximity to the pacemaker; a minimum distance of 15 cm
should be observed.
PMID- 9763828
TI - [Mycophenolic acid: a welcome adjunct immunosuppressant after organ transplants].
AB - Three major double-blind trials in kidney transplantation patients have shown
that mycophenolic acid (mycophenolate mofetil), added to an immunosuppressive
regimen consisting of cyclosporine and prednisone, reduces the incidence of acute
rejection after kidney transplantation by 50%, during the first six months. This
statistically significant reduction is achieved equally with daily doses of 2 or
of 3 g. In view of the fact that the side effects (diarrhoea, abdominal cramps,
leukopenia) are more frequently found in the patients treated with 3 g, it is
advised to prescribe 2 g mycophenolic acid. As acute rejection is a risk factor
for the development of chronic rejection and because a beneficial effect of
mycophenolic acid on chronic rejection in animal models has been observed, there
may also be an effect on late graft loss due to chronic rejection after kidney
transplantation in man.
PMID- 9763829
TI - [Straying in the methodology. I. Introduction].
AB - In recent decades clinical studies with patients have gained qualitative and
quantitative importance. This has led to growing interest in methodological
quality. At present, doctors need more methodological knowledge. Sophisticated
software enables almost everyone to carry out the most exotic of statistical and
epidemiological analyses, but the methodological implications are too often
incompletely understood. In a series of column-like short articles methodological
items will be discussed, in order to point out frequent errors, fallacies and
practical problems.
PMID- 9763830
TI - [Straying in the methodology. II. Bias introduced by questionnaires].
AB - Some characteristics of self-report questionnaires can result in bias in
responding. When a test item or a questionnaire is biased, the observed scores
form an imprecise measurement of reality as a consequence of systematic errors of
measurement. Causes of such bias are: unclear instructions, vague wording of the
test items, culture-bound item content, suggestive questions, framing of
questions, social desirability of certain answers, faking good, faking bad and
the recall bias.
PMID- 9763831
TI - [No increase in cancer incidence due to high-voltage cables in Odijk].
AB - OBJECTIVE: To determine the incidence of cancer in Odijk and the connection if
any of the occurrence of cancer with the presence of a high-voltage cable
constructed there in the fifties. DESIGN: Descriptive. SETTING: Public Health
Services, South-East Utrecht, the Netherlands. METHOD: Data on the numbers of new
cancer patients in Odijk over the period 1985/'96 were obtained from general
practitioners, from the Integral Cancer Centre Mid-Netherlands (IKMN) and from
the Foundation Dutch Study Group Leukaemia in Children. The classifications were
according to age and to distance from the home to the high-voltage cable. The
electric and magnetic field strengths in dwellings situated less than 28 m from
the cable were calculated. RESULTS: Cancer was diagnosed in 131 patients in the
period 1985/'96, 127 adults and four children. The cases in 3 of 4 children
occurred in the period 1993/'96. Over the period 1990-1994, the registered cancer
incidence did not deviate from the expected incidence in the IKMN region, nor
from the mean incidence in the Netherlands. Neither for adults nor for children
was a relationship found between cancer and living in the vicinity of the high
voltage cable. The exposure to the electric field of persons living in houses
near the cable was maximally 7%, and exposure to the magnetic field maximally
6.5% of the maximal liminal values applied in the Netherlands on recommendation
of the Health Council. CONCLUSION: No relationship existed between development of
cancer and the presence of a high-voltage cable.
PMID- 9763832
TI - [The treatment of basal cell carcinoma patients by dermatologists in Netherland].
AB - OBJECTIVE: To determine the policy of dermatologists practising in the
Netherlands in the treatment of basal cell carcinoma. DESIGN: Written enquiry.
SETTING: Catharina Hospital, Eindhoven, the Netherlands. METHOD: All 293
dermatologists practising in the Netherlands were sent a questionnaire in May
1996 containing 15 questions about diagnosis and treatment of basal cell
carcinoma. RESULTS: Eighteen forms dropped off because of termination of the
practice or joint completion in group practices. The response was 76% (208/275).
The diagnosis was made usually on the basis of histological examination (71% of
the respondents; 84% in a tumour recurrence). Excision was the preferred
treatment for all subtypes of basal cell carcinoma; second choices were
cryosurgery or curettage/electrocoagulation. Roentgen contact therapy has been
practically abandoned. New methods such as photodynamic therapy and immunotherapy
are being used only sporadically on an experimental basis. Most dermatologists
regarded tumour recurrences as a bigger problem than primary tumours. They
attempt to reduce the percentage of recurrences by giving advice about risk
factors (sunlight). CONCLUSION: Too little use is being made of diagnostic biopsy
to enable an optimal choice of therapy of basal cell carcinomas, especially in
cases of recurrence tumours.
PMID- 9763833
TI - [A severe anaphylactic shock caused by spraying the oak processionary caterpillar
(Thaumetopoea processionea) in North Brabant].
AB - The processionary caterpillar, Thaumetopoea processionea, caused much
inconvenience in the Netherlands in 1996-1997; from the medical point of view,
mostly itching and skin rash. After contact with stinging bristles of the
caterpillar and with the pesticide Dimilin SC-48, of which diflubenzurone is the
active agent, a 72-year-old man had to be resuscitated because of ventricular
fibrillation caused by hypotension related to relative underfilling and low
systemic vascular resistance. He made a good recovery. Such life-threatening
situations can be prevented by publicly announcing plague control measures and
closing of the affected areas to the population, with ample margins.
PMID- 9763834
TI - [Two children with a rare etiology of torticollis: primitive neuro-ectodermal
tumor and Grisel's syndrome].
PMID- 9763835
TI - [Children who cough and wheeze: relief of symptoms after parents stop smoking].
PMID- 9763836
TI - [Kindler syndrome].
PMID- 9763837
TI - [The hyperglycemic dehydration syndrome].
AB - Two patients, men aged 47 and 64 years, were found in a comatose condition in
their homes, after a period of fatigue, polyuria and polydipsia. They had not
been known to suffer from diabetes mellitus, but now displayed a hyperglycaemic
hyperosmolar non-ketoacidotic disorder as the first manifestation of diabetes
mellitus type 2. In that condition, just sufficient insulin is present to
counteract ketone production, but not enough to prevent hyperglycaemia.
Neurological and thromboembolic manifestations, possibly fatal, may result from
severe dehydration brought about by a vicious circle in which osmotic diuresis
reduces the effective circulating volume, causing renal function to decrease and
hyperglycaemia to increase even more. Both patients recovered fully after
adequate treatment with solutions of NaCl and glucose.
PMID- 9763838
TI - [How much mental illness is there in the Netherlands?].
AB - According to the results of recent epidemiological studies, over 3 million of the
people in the Netherlands per year are supposed to suffer from severe mental
disorders. This high prevalence should be regarded in connection with the
diagnostic criteria and interview techniques applied. The final results of such
epidemiological studies depend on where one draws the dividing line between
clinically relevant mental disorders and normal problems of life.
PMID- 9763839
TI - [The risk of a multiple myeloma in patients with paraproteinemia: a myeloma risk
score developed in the region of the Comprehensive Cancer Center West].
AB - Diagnoses in patients with paraproteinaemia are diverse; few (mostly single
centre based) studies are known that describe incidence, diagnoses and follow-up
in patients with paraproteinaemia. In the region of the Comprehensive Cancer
Centre West in the Netherlands (population 1.6 million, 1992) a population-based
registry was set up in the period 1991-1993. Patients (n = 1464; median age: 72
years; range: 16-102) were entered by clinical chemists, internists,
haematologists, and pathologists. Multiple myeloma and plasmacytoma were
diagnosed in 261 patients (18%), paraprotein-related haematological diseases in
159 patients (11%) and paraprotein-related internal diseases in 210 patients
(14%). After bone marrow examination monoclonal gammopathy of unknown
significance (MGUS) was diagnosed in 207 (14%) patients. No further diagnosis
could be made in 627 (43%) patients mostly for lack of supplementary bone marrow
and (or) X-ray examinations. Consequently, more than two-thirds of all patients
with a newly found paraprotein did not show any sign of a haematological
malignancy. Using these data a 'myeloma risk score' was developed to predict the
presence of a multiple myeloma based on paraprotein type and concentration,
aiding the physician in determining which patients should undergo further bone
marrow and skeletal examinations.
PMID- 9763840
TI - [Multiple myeloma; treatment in the year 1998].
AB - There are a number of studies dealing with intensive chemotherapy and stem cell
transplantation in multiple myeloma. As to autologous transplantation best
results have been obtained with younger patients (below 60 years) who had
responsive disease and received their transplant within one year after start of
treatment. Unfavourable prognostic factors were a high beta 2-microglobulin level
and abnormal cytogenetics including any translocation or chromosome 11/13
abnormalities. Only one phase III study has been published, indicating a
favourable effect of autologous transplantation. Despite the existence of a so
called 'graft-versus-myeloma effect' the overall outcome of patients after
allogeneic transplantation is not better than after autologous transplantation,
probably due to the inclusion in the published studies of heavily pretreated and
refractory patients responsible for a high treatment related mortality. The
ultimate value of intensive treatment of multiple myeloma will become clear in
the coming years when more data become available from current phase III studies
including the Dutch HOVON multicentre trial in which conventional treatment is
compared with intensified therapy including bone marrow ablation and autologous
stem cell transplantation.
PMID- 9763841
TI - [Acute urinary retention in women].
AB - Acute urinary retention in women is not a common problem. The incidence is 0.07
per 1000 inhabitants per year. The causes of acute urinary retention can be
divided into four groups: obstructive, neurological, pharmacological and
psychogenic. More than half of acute urinary retentions occur after surgery or
parturition. The most common obstructive cause is a gynaecologic tumor. A
psychogenic cause is a diagnosis per exclusionem. The treatment of the acute
urinary retention has to be catheterisation before further investigation is done.
PMID- 9763842
TI - [The cost of sickness in the Netherlands in 1994; the main determinants were
advanced age and disabling conditions].
AB - OBJECTIVE: To estimate the costs of health care in 1994, the development of the
costs assigned to specific diseases, and the future costs. DESIGN: Descriptive.
SETTING: Erasmus University, Department of Public Health, Rotterdam, the
Netherlands. METHOD: For each health care sector, costs were allocated to 62
diagnostic groups, age and sex making maximal use of national registries and
other sources with data on health care use in the Netherlands. RESULTS: More than
80% of the 60 billion Dutch guilders that were spent on health care in 1994 could
be assigned to specific diseases. Most costs were made for non-fatal diseases
like mental deficiency, dementia and musculoskeletal disease. Except for
cardiovascular disease, the share of major causes of death in the total costs was
not significant. Average costs per inhabitant were low during youth and adulthood
but increased exponentially with age from age 50 onwards. Between 1988 en 1994,
health care costs experienced an annual growth rate of 5.2%, caused by price and
wage increases (one half), ageing (a quarter) and other effects on health care
costs such as epidemiological and technological change (a quarter). CONCLUSION:
The main determinants of health care use in the Netherlands were old age and
disabling conditions. Due to ageing and other influences, real health care costs
in the years to come will increase by an average annual rate of 2.4%.
PMID- 9763843
TI - [Increase of surgical day treatment in the Netherlands].
AB - OBJECTIVE: To assess the quantitative development of day surgery in the
Netherlands. DESIGN: Descriptive. SETTING: St. Antonius Hospital, Nieuwegein, the
Netherlands. METHOD: Numbers of admissions in the period 1984-1995 were obtained
from Dutch data bases of the National Hospital Institution (NZi). From SIG Health
Care Information numbers were obtained with regard to seven specified
interventions in the years 1991 to 1995, i.e. breast tumour excision, inguinal
hernia repair, varicose vein operation, laparoscopic sterilisation, knee
arthroscopy, cataract operation and tonsillectomy. The increase if any of the
number of interventions in day care was determined by placing the hospitals in
the order of decreasing proportions of day care, and subsequently applying the
proportions of the 5th and 10th hospitals, respectively, to the whole group.
RESULTS: The number of day care admissions rose from 172,000 (9.9% of all
admissions) to 649,000 (29.1%). Of all interventions studied, the percentage
carried out in day care increased; the percentages varied greatly from one
hospital to another. In 1995, the mean number of interventions in daytime was
115,000 (57% of all 201,000 interventions). The shift from interventions during
hospitalization to day care would be 42,000 and 51,000 (21% and 25% respectively,
of 201,000), respectively; operations performed in day care would then amount to
166,000 (83% of the total number of interventions) and 157,000 (78%). CONCLUSION:
Of the interventions studied, the proportion carried out in day care increased to
57%. In view of the intra- and interhospital differences, a considerable increase
of day care in the near future is possible.
PMID- 9763844
TI - [Ocular infection by Pseudomonas aeruginosa in a mechanically ventilated
patient].
AB - A 59-year-old man developed bilateral keratitis several weeks after the
initiation of mechanical ventilation because of respiratory failure and sepsis
following abdominal surgery. Colonisation of the upper airways by P. aeruginosa
had been established before. Invasion through corneal epithelial defects based on
dehydration keratitis was the presumed route of infection. Despite aggressive
treatment, including antibiotics, the infection was rapidly progressive in both
eyes. The patient died of deterioration of his general condition. In order to
prevent such eye infections in a patient on mechanical ventilation, there is a
need of good eye care, prevention of corneal lesions and alertness, especially
when the patient is colonised by virulent micro-organisms like P. aeruginosa.
PMID- 9763845
TI - [Major psychiatric side effects of interferon alpha-2b].
AB - The Netherlands Pharmacovigilance Foundation Lareb and the Drug Safety Unit of
the Inspectorate for Health Care in 1997 received 6 reports of serious
psychiatric symptoms during the use of interferon alpha-2b. Of these patients,
three men aged 42, 49 and 62 years and three women aged 31, 40 and 33 years, two
had had psychic symptoms before. Depression or psychosis developed 12-24 weeks
after the start of the use of interferon alpha-2b with 3-10 million IU per week
subcutaneously because of chronic hepatitis B or C. After cessation of the
medication, four patients recovered after a few days or weeks; the course of one
patient was unknown, one patient had committed suicide. Knowledge of these
psychiatric adverse drug reactions to interferon alpha-2b can contribute to early
recognition by the physician and timely treatment of the symptoms.
PMID- 9763846
TI - [More openness about the registration of drugs in the Netherlands. College for
the Review of Medicinal Products].
AB - The applications submitted to the Drugs Evaluation Board contain information that
is important for correct use of the drug in question in clinical practice. Not
all this information is given in the published literature, certainly not at the
time of registration. Recently, legal provisions on publication of data in
connection with a registration were clarified. The Board no longer sees any
objection to introduction of a national, public assessment report explaining the
arguments involved. The quality of evaluation of pharmaceutical products, also in
connection with the reimbursement system, cannot but improve if a justification
of the evaluation is published.
PMID- 9763847
TI - [Two cold bones].
PMID- 9763848
TI - [A hundred years of orthopedics in the Netherlands. X. Sports injuries].
PMID- 9763849
TI - [The Montignac methods: scientific foundation questionable].
PMID- 9763850
TI - [Envisioning the future in public health 1997. II. Developments in the state of
health].
PMID- 9763851
TI - [Infection with Mycobacterium genavense in 2 HIV-seropositive patients in
Amsterdam].
PMID- 9763852
TI - [Netherlands Society of Urology].
PMID- 9763853
TI - [Hyperthyroidism induced by iodinated roentgen contrast media].
AB - Three patients with subclinical hyperthyroid goitre, women aged 63, 72 and 75
years following intravenous administration of an iodinated contrast medium
developed hyperthyroidism with a marked rise of the concentration of free T4.
Thyreostatic agents were unsuccessful in two patients, the third was left
untreated. Hyperthyroidism improved spontaneously in all three. Iodine-induced
hyperthyroidism is rare and is usually encountered in patients with a pre
existent autonomous thyroid function. Treatment of iodine-induced hyperthyroidism
is essentially exclusively symptomatic. Prophylaxis with sodium perchlorate
should be considered in cardiac patients with a goitre and a subnormal level of
thyroid-stimulating hormone (TSH).
PMID- 9763854
TI - [Chronicle of a defective heart valve prosthesis].
AB - The Bjork-Shiley convexo-concave (BScc) strut fracture problem is about to enter
its third decade. At present, valve carriers still face the risk of outlet strut
fracture; a risk which does not seem to decline. The temporising attitude of the
manufacturer has led to far more victims than would have been necessary but also
the Food and Drug Administration, regulatory agencies outside the US and the
medical community share responsibility for this problem.
PMID- 9763855
TI - [Lessons from a heart valve prosthesis controversy].
AB - Two lessons are to be learnt from the Bjork-Shiley heart valve prosthesis
tragedy. In the first place pharmacoepidemiologic studies are seriously hampered
by recent privacy legislation. Individual patients carrying such a prosthesis
cannot be traced and advised as to their health risks any more, because their
legal autonomy has to be respected. This is clearly not to their advantage. In
the second place the atmosphere of marketing and litigation and the increasing
dependency of researchers on money from sources with conflicting interests is not
conducive to a well-informed and balanced judgement of the epidemiological
evidence of safety and efficacy of medical treatments.
PMID- 9763856
TI - [Immunology in the clinical practice. XVI. Paraneoplastic syndromes of the
nervous system: pathogenesis and diagnosis].
AB - Paraneoplastic neurological syndromes are believed to result from ectopic
expression of onconeural antigens by tumours. The resulting immune response is
not only directed against the tumour but also cross-reacts with the same or
similar antigens in the nervous system. The immune response generates high titred
autoantibodies that are associated with specific tumours and neurological
syndromes. Paraneoplastic autoantibodies help diagnose neurological syndromes and
help direct the search for an underlying tumour. In paraneoplastic syndromes, the
course of the tumour is relatively mild. Detection of the autoantibodies might
lead to early diagnosis and immunomodulation and anti-tumour treatment before
irreversible neuronal cell loss and deficits set in.
PMID- 9763857
TI - [Treatment of subglottic laryngitis (pseudocroup): steroids instead of steam].
AB - Traditionally, steaming with warm moist air was recommended for the treatment of
subglottic laryngitis (pseudocroup). However, no favourable effect has ever been
demonstrated. Consequently, steaming is no longer to be advised. Systemic
corticosteroids, already of proven effectiveness in severe croup, were shown to
be also effective when administered in a single oral dose in moderately severe
disease. Besides, in various studies, nebulisation of budesonide (2000
micrograms) with a jet nebuliser had a good effect on the clinical course of
croup. However, dose-effect studies are still lacking. A single dose of
corticosteroids, either systemic or inhaled via a jet nebuliser, should be the
first line therapy in moderate and severe croup syndrome. In milder cases no
specific treatment is needed as the disease is self-limiting.
PMID- 9763858
TI - [Roaming through methodology. III. Randomization at the level of the physicians].
AB - In some studies randomization at the patient level is not possible; randomization
at the doctor's level can then be applied. However, statistical analysis at the
level of the individual patient data can lead to wrong conclusions in such a
study design. By basing the analysis on the averages per doctor a statistical
test can be performed which guarantees the correct significance level. The
correct sample size can be found by means of a correction factor that depends on
the variation between the doctors. The data of a study with randomization at the
doctor's level can be analysed in a more sophisticated way by means of so-called
'mixed models' that take account of possible variation between doctors.
PMID- 9763859
TI - [Tuberculosis of the larynx].
AB - Laryngeal tuberculosis was diagnosed in two men, a 73-year-old man Dutch by birth
and a 40-year-old one Turkish by birth. In the former patient it was probably
primary tuberculosis, in the latter secondary (he had lung tuberculosis as well).
The clinical picture was highly suggestive of laryngeal carcinoma in both
patients. They both recovered with chemotherapy. Laryngeal tuberculosis may mimic
laryngeal carcinoma. The diagnosis is based on Ziehl-Neelsen staining, culture
and polymerase chain reaction (PCR) on Mycobacterium tuberculosis. Because
laryngeal tuberculosis is highly infectious, the patient has to be nursed in
isolation and people in his or her environment have to be screened. The response
of laryngeal tuberculosis to chemotherapy is good.
PMID- 9763860
TI - [Pathogenesis of pre-eclampsia].
PMID- 9763861
TI - [Urination alarm training also successful with 5-7 year olds suffering from
enuresis nocturna].
PMID- 9763862
TI - [Two children with an unusual cause of torticollis: primitive neuro-ectodermal
tumor and Grisel's syndrome].
PMID- 9763863
TI - [A swelling in the distal part of the thigh].
AB - A swelling in the distal thigh may be caused by a tumour of bone or soft tissues,
an aneurysm or an inflammation. Signs of inflammation may render interpretation
more difficult. Four males aged 60, 48, 15 and 81 years had had a swelling in the
popliteal space or above the knee, in some cases with pain. Supplementary
examinations, especially MRI scanning and arteriography did not always result in
a diagnosis. The diagnosis could be made, however, during operation: an empyemic
thrombosed popliteal artery aneurysm, a liposarcoma, pyomyositis and suture
dehiscence of a plastic prosthesis of the popliteal artery. After treatment,
consisting of or started during the operation, uneventful recovery occurred.
PMID- 9763864
TI - [Dietary trans-fatty acids: a risk factor for coronary disease].
AB - Unsaturated fatty acids with their double bond in trans configuration raise serum
low-density lipoprotein (LDL) cholesterol and lipoprotein(a) levels, and lower
high-density lipoprotein (HDL) cholesterol in humans when substituted for cis
unsaturated fatty acids in the diet. These effects should increase the risk of
coronary heart disease, which is confirmed by epidemiological studies. Trans
fatty acids are formed from cis unsaturated fatty acids during hydrogenation of
vegetable oils in food industries. Until recently, major dietary sources of trans
fatty acids in the Netherlands were frying fats, shortenings, and margarines,
which in the past contained up to 50% of trans fatty acids. Nowadays, most
shortenings and margarines sold in the Netherlands have a low trans fatty acid
content due to manufacturing changes in the recent past. However, frying fats
used in fast-food outlets still contain over 30% of trans fatty acids. French
fries sold in these outlets provide 7-8 g of trans fatty acids per portion.
Producers of frying fats for fast-food outlets therefore should also reduce the
trans fatty acid content of their products as much as possible.
PMID- 9763865
TI - [Ambulatory blood pressure measurement].
AB - Non-invasive ambulatory blood pressure monitoring (ABPM) is used as an additional
diagnostic procedure particularly in specialist hypertension care. One
application is diagnosing white coat hypertension. In general practice there is
no established place for this diagnostic tool so far. At this time several
studies are being carried out to investigate the prognostic value of ABPM. There
are protocols of validation for ABPM monitors; nine of the 45 available up to now
have been approved by the two most important test protocols. Reference values for
normotension and hypertension are determined for the general population, but not
for special groups of patients or for exercise conditions. One of the frequently
mentioned advantages of ABPM over office blood pressure reading is the higher
correlation of ABPM with hypertensive organ damage. To a large extent this
superiority is based on the larger number of blood pressure readings. Repeated
standardized office measurements reduce this advantage of ABPM.
PMID- 9763866
TI - [Chemotherapy in metastasized breast carcinoma].
AB - Metastatic breast cancer is still an incurable disease. Standard hormonal and
chemotherapeutic treatment modalities yield at the best a survival advantage of 1
to 2 years. However, palliation is still the second, very important goal of
treatment for metastatic disease. First-line chemotherapeutic treatment with an
anthracycline-containing regimen induces a response in about half the patients.
In second-line treatment docetaxel is an effective agent even in patients failing
first-line therapy with an anthracycline-containing regimen. There is no
effective standard third-line chemotherapy scheme.
PMID- 9763867
TI - [Clinical thinking and decision making in the practice. A patient with fever of
unknown origin].
AB - A 75-year-old woman was admitted because of fever of unknown origin (FUO). In the
year before the current admission she developed myalgias and was treated for
polymyalgia rheumatica with low-dose prednisone. Her complaints persisted and
prednisone was discontinued. Five months before the present admission she
developed fever (37.7-38.9 degrees C), malaise, fatigue and occipital headache.
Laboratory tests showed an elevated erythrocyte sedimentation rate (98 mm in the
first hour) and a severe hypochromic, slightly microcytic, anaemia. Although a
recent temporal artery biopsy was negative, a second biopsy was taken which
showed giant cell arteritis. The patient was treated with high-dose prednisone
(60 mg daily) and made a full recovery. It is emphasized that temporal arteritis
is a common cause of FUO in the elderly.
PMID- 9763868
TI - [The yield of endoscopic follow-up after removal of adenomatous polyps from the
colon].
AB - OBJECTIVE: To determine the results of follow-up endoscopy after resection of
adenomatous polyps from the colon. DESIGN: Retrospective. SETTING: De Heel
Hospital, department of Internal Medicine, Zaandam, the Netherlands. PATIENTS AND
METHOD: The 124 patients, 66 males and 58 females, with a mean age of 53 years
(range: 23-74), in whom a colonpolyp had been removed endoscopically, who had no
colonic carcinoma and no positive family history, were registered for follow-up
after one year and after 3 or 5 years. In 1997, data were collected on the polyps
found and removed at follow-up. RESULTS: At the original coloscopy, 68 patients
(55%) had one polyp, 46 (37%) had two to four polyps and 10 (8%) > or = five
polyps. The localizations of the polyps were: rectum 17%, sigmoid 66%, descending
colon 12%, transverse colon 3%, ascending colon 1% and caecum 1%. Over one-third
of the polyps were larger than 1.5 cm. Ninety-eight patients underwent a first
follow-up endoscopy after an average of 12 months (range: 0.4-57); one or more
polyps were found and removed in 37 of them (38%). At a second follow-up
endoscopy after an average of 28 months (range: 5.4-68 months), polyps were again
found and removed in 26 of the 57 patients (46%). If two or more polyps had been
removed at an earlier coloscopy, the risk of polyps being found again at the next
coloscopy was larger (p < 0.001).
PMID- 9763869
TI - [Psychiatric symptoms in refugees reported to the Psychiatric Center De Vonk].
AB - OBJECTIVE: To determine traumatic experiences and psychological symptoms in
refugees reported to the psychiatric centre De Vonk, and the relationship between
biographical data, experiences of violence and post-traumatic stress symptoms on
the one hand and the referral or admission policy on the other. DESIGN:
Descriptive. SETTING: Centre '45, refugee unit De Vonk (department for the
treatment of traumatized refugees and asylum seekers), Noordwijkerhout, the
Netherlands. The psychiatric centre De Vonk comprises, apart from an outpatient
clinic and a daytime clinic, a department created for the clinical treatment of
refugees with symptoms related to traumatization. METHODS: The main biographical
and background data were collected. The first interview was routinely preceded by
the Harvard trauma questionnaire (HTQ) and the Hopkins symptom checklist (HSCL
25), if necessary with the aid of an interpreter. The HTQ measures experiences of
violence and post-traumatic stress symptoms; the HSCL-25 comprises an anxiety
scale and a depression scale. RESULTS: Biographical data were obtained from 232
patients and questionnaire data from 169 patients. The population was
heterogeneous as regards region of origin, duration of the stay in the
Netherlands, education and age. Serious forms of violence were reported, such as
abuse, torture and war violence, and many symptoms of anxiety and depression were
mentioned. The scores for posttraumatic stress symptoms exceeded the clinical
reference values in 82% in the group examined. Of the referred patients, 37% were
admitted to the clinic. CONCLUSION: In spite of the diversity of language,
culture and education among the refugees/asylum seekers referred to De Vonk, it
proved adequately possible in practice to use standardized psychological and
psychiatric instruments in this group of patients. The symptom level of the
patients referred was particularly high.
PMID- 9763870
TI - [An rare cause of vaginal discharge: sarcoma botryoides].
AB - A general practitioner was consulted by a 15-year-old girl, virgo, suffering from
foetid vaginal discharge. The girl was seen by a gynaecologist after
antimicrobial treatment had failed. Further investigations revealed that a
embryonal rhabdomyosarcoma was present, a sarcoma botryoides. The tumour
originating from the cervix uteri was resected completely after which
chemotherapy was started. One year later there were no sequelae or indications of
metastases. Sarcoma botryoides has a better prognosis than other types of
rhabdomyosarcoma. The prognosis is also influenced by the site of origin, which
is favourable for the cervix.
PMID- 9763871
TI - [Subspecialty blood transfusion medicine].
AB - The unification of Europe, the related principle of self-sufficiency and the
prevention of blood banks turning into bureaucratic institutes that lose
connection with bedside medicine underscores the need for training in transfusion
medicine and its international organization. In most European countries
transfusion medicine is now recognized as a specialty in its own right. In the
Netherlands it was decided to recognize transfusion medicine as subspecialty of
Internal Medicine. This new initiative led to a training programme of 6 years in
all, of which the last 18 months are devoted to transfusion medicine exclusively.
The importance of continuous education and practice in both fields is recognized.
PMID- 9763872
TI - [Fifty years of the column 'Question and Answer'].
AB - The section 'Question and answer' in the Nederlands Tijdschrift voor Geneeskunde
(Dutch Journal of Medicine) has existed for over 50 years. Medical questions of
readers are published anonymously and answered by an anonymous expert consulted
by the editorial staff. At first the column grew rather large but in the last few
decades it shrank to only few publications a year. Due to improvements in
communication (Internet) and provision of information (electronic databases) it
appears that the column, as a medium for questions of readers, is becoming
obsolete.
PMID- 9763873
TI - [Optimization of the antibiotics policy in the Netherlands. II. SWAB guidelines
for the antimicrobial therapy of pneumonia treated at home and nosocomial
pneumonia].
PMID- 9763874
TI - [Optimization of the antibiotics policy in the Netherlands. I. The Foundation
Task Force for Antibiotics Policy (SWAB)].
PMID- 9763875
TI - Prooxidant actions of carotenoids in biologic systems.
AB - The potential for carotenoids to modulate chronic disease risk is currently under
investigation, and renewed interest has been placed on achieving a better
understanding of the mechanisms of action of carotenoids in biologic systems.
Available data currently show that the antioxidant activity of these compounds
may shift into prooxidant activity, depending on the redox potential of the
carotenoid molecules as well as on the biologic environment in which they act.
The prooxidant potency of these compounds is determined by several factors,
including oxygen tension, carotenoid concentration, and interactions with other
antioxidants. Prooxidant activity can induce either beneficial or harmful results
in biologic systems and influence the development of human chronic diseases.
PMID- 9763876
TI - Effects of chromium on body composition and weight loss.
AB - Chromium is an essential nutrient involved in the regulation of carbohydrate and
lipid metabolism. Normal dietary intake of chromium in humans and farm animals is
often suboptimal. In addition to its effects on glucose, insulin, and lipid
metabolism, chromium has been reported to increase lean body mass and decrease
percentage body fat, which may lead to weight loss in humans. The effects of
chromium on body composition are controversial but are supported by animal
studies, which increase their validity. A subject's response to chromium depends
on his or her chromium status, diet consumed, type and amount of supplemental
chromium, and study duration. There have been no confirmed negative effects of
chromium in nutritional studies. Chromium is only a small part of the puzzle in
the control of weight loss and body composition, and its effects, if present,
will be small compared with those of exercise and a well-balanced diet.
PMID- 9763877
TI - Agouti/melanocortin interactions with leptin pathways in obesity.
AB - The cloning of mouse obesity genes and their human homologues provides unique
opportunities to identify novel cellular targets for therapeutic intervention.
The first of these to be cloned, agouti, antagonizes central nervous system
melanocortin receptor (MCR) binding, resulting in hyperphagia and an
obesity/hyperinsulinemia syndrome. There appears to be significant cross-talk
between the agouti and leptin signaling systems. Agouti antagonism of central
nervous system (CNS) MCR binding inhibits the anorexic effects of leptin, whereas
agouti up-regulates adipocyte leptin expression, serving to limit the magnitude
of agouti-induced obesity. The effects of agouti and leptin mutations on obesity,
however, are independent and additive. Agouti also regulates adipocyte lipid
metabolism, functioning both to increase the expression and activity of lipogenic
genes and to inhibit lipolysis. Both of these actions occur via a Ca(2+)
dependent mechanism, suggesting that modulation of adipocyte Ca2+ transport may
be a key target for further investigation.
PMID- 9763878
TI - Diet, lifestyle, and colorectal cancer: is hyperinsulinemia the missing link?
AB - Several dietary and other lifestyle factors have been implicated in the
development of colorectal cancer. However, the precise nature and actual
magnitude of the relationship between individual nutrient intakes and other
lifestyle factors and colorectal cancer risk are not clear. A unifying hypothesis
has recently been proposed that explains why obesity, physical inactivity,
alcohol, and consumption of a typical Western diet increase colorectal cancer
risk. This hypothesis suggests that these dietary and other lifestyle factors are
associated with insulin resistance and hyperinsulinemia and that
hyperinsulinemia, in turn, may stimulate growth of colorectal tumors. Two
recently published large prospective epidemiologic studies indicate a significant
increase in colorectal cancer risk in subjects with diabetes mellitus, thereby
supporting this hypothesis.
PMID- 9763879
TI - Slow-release iodine in local water supplies reverses iodine deficiency disorders:
is it worth its salt?
AB - An alternative approach to supplying iodine to isolated populations through the
use of slow-release iodine in silicone matrices that float in the water supply
was tested in remote desert areas of the Sudan. There was a differential impact,
as judged by indicators of iodine nutriture, and these indicators provided
varying indications of the iodine status of the population.
PMID- 9763880
TI - Underexploited African grain crops: a nutritional resource.
AB - The African grain deficit is projected to surpass its current production of 50 x
10(6) metric tons/year by the turn of the century. The biodiversity of the
African continent, on which there are more native cereals than on any other
continent, can serve to reduce the vulnerability of the continent's populations
at serious risk of food shortages. Traditional grain and root crops have provided
the energy underpinning for Africa since the emergence of bipedal hominids. By
resurrecting some of these "lost crops" in their native areas, the food security
of those areas can be enhanced. In addition, some of these crops lend themselves
to introduction into other nutritionally challenged areas of the world with
similar geoclimatic characteristics.
PMID- 9763881
TI - Acute effects of soft drink intake on calcium and phosphate metabolism in
immature and adult rats.
AB - OBJECTIVE: To test the acute effects of the intake of a phosphoric acid
containing soft drink on acid-base balance and on calcium and phosphate
metabolism. MATERIAL AND METHODS: We studied 14 young adult male Sprague-Dawley
rats aged 90 days, and 14 immature animals aged 30 days. Half of the animals in
each group were randomly assigned to receive either tap water (controls), or Coca
Cola ad libitum for seven days. After this period, the rats were individually
placed in metabolic cages to collect 24 hours urine, and they were exsanguinated
by aortic puncture. Immediately, pH and ionized calcium were measured in whole
blood. Creatinine, phosphate and total calcium were determined in the urine and
plasma. Plasma levels of PTH, 1 alpha, 25 (OH)2 D3 and 25 OH D3 were measured by
IRMA and RIA commercial kits. RESULTS: The animals receiving the soft drink, both
adults and immature, developed significant hypercalciuria and hyperphosphaturia.
In immature animals, the plasma pH dropped from 7.45 +/- 0.04 to 7.33 +/- 0.02 (p
< 0.05) but did not change in adult animals. Ionized calcium dropped
significantly from 1.06 +/- 0.04 to 0.80 +/- 0.06 meq/L (p < 0.05) in immature
animals but not in the adult animals. Only immature rats developed significant
reduction of 1 alpha, 25 (OH)2 D3 and 25 OH D3, whereas only the adult rats
developed significant hyperparathyroidism. Immature animals showed more severe
derangement of calcium and phosphate metabolism related to soft drink intake.
PMID- 9763882
TI - Hemodynamic indexes in newborns using the arteriovenous oxygen content
difference.
AB - OBJECTIVE: To determine in peripheral blood samples of newborns (NB) cardiac
output (Q), cardiac index (CI), systemic vascular resistance index (SVRI), and
effective oxygen transport (EO2T), through arteriovenous oxygen content
difference ([C(a-v) O2]). DESIGN: Comparative survey. SETTING: Healthy NBs and
NBs in intermediate care in third level medical attention units. MATERIAL AND
METHODS: Forty-seven NB (17 pre-term) were prospectively studied in August and
September/1995. A blood sample of 0.4 mL was taken from the umbilical or femoral
vein and from the umbilical, radial or femoral artery. The inferencial statistics
were done with a t test and Pearson's correlation coefficient. Significance was
considered if p < 0.05. RESULTS: Cardiac output ranged from 0.3 to 1.4, mean =
0.6 L/min +/- 0.24 (+/- SD); CI ranged from 1.8 to 6.4 L/min/m2 body surface area
(mean = 3.3 +/- 1.2); SVRI ranged from 533 to 2,391 dyne/sec/cm-5/m2 BSA (mean =
1,317 +/- 494); EO2T ranged from 307 to 1,017 mL/min/m2 BSA (mean = 549 +/- 186);
the [C(a-v) O2] ranged from 3.1 to 10.7% in volume (mean = 6.8 +/- 2.1). No
significant differences were found in Q between pre-term and full-term NB nor was
there any correlation between Q and gestational age. CONCLUSIONS: The [C (a-v)O2]
is a good alternative to obtain indexes in peripheral blood of NB without
cardiopathy, whenever other less invasive and more sophisticated methods are
unavailable. In order to calculate the indexes in critically-ill patients, it is
necessary to measure O2 consumption prior to applying this method.
PMID- 9763883
TI - [Neuropsychological evaluation in patients with Parkinson's disease].
AB - OBJECTIVE: To analyze the neuro-psychological performance of patients with
Parkinson's, disease (PD), in comparison with a group of patients with frontal
lobe lesions (FLL) and a control group. METHODS: Eighteen patients with PD, 10
patients with FLL and 10 controlls of similar age and scolarity were studied.
Neuro-psychological evaluation included tests of the visuospatial, execution,
attention and concentration, memory and language areas. The tests were classified
in two categories: those requiring motor responses and those that do not.
RESULTS: Patients with PD and FLL had lower scores them the controls in the
visuospatial, attention and concentration and language areas, with statistical
significance in some cases. The differences with the controls persisted in some
tests requiring and not requiring motor response. CONCLUSIONS: Frontal lobes have
an important role in the neuro-psychological profile of patients with PD.
Cognitive deficits in these patients is unrelated to the motor impairment of the
disease.
PMID- 9763884
TI - [Sonographic patterns by transcranial Doppler in acute cerebral infarction].
AB - AIM: To evaluate the correlations between the patterns of Transcranial Doppler
(TCD) and the extent and pathophysiologic mechanism of the ischemia as well as
the prognosis of patients with acute ischemic stroke. METHODS: 37 patients with
ischemic stroke within the first 24 hours of evolution were examined using TCD,
neuroimaging, and neurologic state at admission and disarcharge. The TCDs were
grouped into four categories: normal, stenotic, hemispheric asymmetry and trunk
occlusion of the middle cerebral artery (MCA); they were correlated with the
extent of brain damage, pathophysiologic mechanism of the stroke and prognosis.
RESULTS: Normal TCD was highly predictive of lacunar infarction secondary to
small vassels disease (p = 0.01) and good recovery (p < 0.02). The stenotic and
hemispheric asymmetry patterns correlated highly with a cortical infarctions (p <
0.05) and a cardioembolic mechanism. The occlusion of the MCA was highly
correlated with a large infarction (p < 0.01) and with poor outcome and death (p
= 0.004). CONCLUSIONS: Our data show that TCD has a value in predicting the
prognosis and the severity, location and pathophysiologic mechanism of cerebral
strokes.
PMID- 9763885
TI - [Clinical competence and clinical performance in diabetes].
AB - OBJECTIVE: To evaluate at the primary health care level, clinical competence and
clinical performance of physicians in the diagnosis and management of diabetes
mellitus type II. MATERIAL AND METHODS: Physicians in 4 primary medical care
units were evaluated using two instruments: a multiple choice questionnaire
(true/false/don't know type) with 224 questions about diabetic cases to explore
clinical competence, and a second one on management of cases of diabetes to
explore the performance in two patients. Both instruments were validated by
experts. The instruments were applied simultaneously to 59 physicians in two
units and only the competence instrument to another 59 physicians of the other
two units. RESULTS: There was a low clinical competence in 57% of the physicians
and without differences between the four units. In performance there was a
significant differences in favor of the unit with less work load; 56% of the
physicians had a very poor performance level. A Spearman correlation competence
versus performance was low in both units (0.16 and 0.10). CONCLUSIONS: The
majority of the physicians had poor or very poor competence and performance and
the latter increased under unfavourable working conditions. There was a
qualitative difference between our instruments as they were not correlated. It is
necessary to improve the working conditions in these units to stimulate their
physicians.
PMID- 9763886
TI - [Parinaud's syndrome in children].
AB - OBJECTIVE: To describe the clinical and ethiologic findings of children with
Parinaud's syndrome. MATERIAL AND METHODS: 11 children fulfilling the clinical
criteria for Parinaud's syndrome were studied. The mean age was 10 years with a
range of 10 months to 14 years. RESULTS: Seven cases were tumors (pineal
germinoma in four and one each with teratoma, astrocytoma, and an undefined
tumor); the remaining 4 cases corresponded to arachnoid cyst in the III
ventricule, cysticercosis, tuberculoma and multiple sclerosis. The main treatment
was surgical including ventriculoperitoneal shunt because of hydrocephalous
secondary to mechanical obstruction. Chemotherapy and radiotherapy were also used
for the tumor cases, and steroids for the multiple sclerosis patient.
CONCLUSIONS: In contrast to adults, Parinaud's syndrome in our children was
associated with a mass, mainly tumoral, which interrupted the afferent and
efferent connections of the midbrain structures, such as posterior commissure,
riMLF or the interstitial nucleus of Cajal.
PMID- 9763887
TI - The role of commercial plasmapheresis banks on the AIDS epidemic in Mexico.
AB - OBJECTIVE: To characterize the circumstances underlying the epidemic of AIDS
associated with blood transfusion in Mexico and to explore the possible
mechanisms for its dissemination. METHODS: A retrospective analysis comparing the
total number of AIDS cases and transfusion-associated AIDS cases and the
male:female ratio reported in Mexico and the U.S. from 1981 to 1996 was done. We
analyzed the relationship between the location of plasmapheresis banks and the
geographic distribution of transfusion-associated AIDS cases and AIDS cases among
paid donors in order to assess the possible role of plasmapheresis banks in its
dissemination. RESULTS: The proportion of transfusion-associated AIDS in the
total number of cases was significantly higher in Mexico than in the U.S. from
1987 through 1996 (p < .0001). A rapid drop in the male:female ratio of AIDS was
observed in Mexico but not in the U.S. coinciding with a growing number of
transfusion associated cases; transfusion has been the main risk factor for AIDS
in women in our country. In 1986, seven States and Mexico City had plasmapheresis
banks: they reported 90% of the cases associated to paid donation and 75% of
those associated to transfusion, despite the fact that commercial blood banks
without plasmapheresis facilities existed in 23 of the other 24 States.
CONCLUSION: There was a difference on the frequency of transfusion associated
AIDS between Mexico and the U.S. which reached epidemic proportions in Mexico. We
believe that plasmapheresis banks played a major role in the dissemination of the
infection in Mexico as paid donors provided a third of the blood used in Mexico
in 1986. These findings highlight important implications for the prevention of
AIDS in developing countries where commercial plasmapheresis practices are still
in operation.
PMID- 9763888
TI - [Diabetes and pregnancy in Mexico].
AB - OBJECTIVE: To review the Mexican studies published in the last 15 years on
diabetes mellitus (DM) and pregnancy. MATERIAL AND METHODS: We found five
descriptive studies on DM and pregnancy and six on the detection of gestational
diabetes (GDM) in normal pregnant women using the oral glucose tolerance test
(OGTT). RESULTS: The first group of studies comprised 689 patients: 331 with
pregestational DM type 2 and 32 type 1; the other 326 patients (47%) had GDM
established by clinical symptoms and hyperglycemia, or by fasting hyperglycemia
(> 140 mg/dL) in at least two ocassions. The distribution of types 1 and 2 was
similar in the five studies. Maternal complications were toxemia in 18%,
polyhydramnios is 10% and urinary infection in 6%. Perinatal mortality was 7%,
congenital malformations in 6%, macrosomia in 25% and prematurity in 8%. In the
puerperium 71 women with GDM were reevaluated: 48 (68%) were type 2, one (1%)
type 1, three (4%) glucose intolerance (GI) and 19 (27%) were normal to an OGTT
test. The six studies on GMD in normal pregnants were done using the OGTT. Three
studies were done in the city of Monterrey, state of Nuevo Leon and show a
prevalence of 4.3 to 6%, mean 5.3%. The other three studies show a prevalence of
10.5 to 11%. In the puerperium, 26 women were reevaluated: only three were type 2
(12%), five GI (19%) and 18 (69%) had a normal response to the OGTT. CONCLUSIONS:
Type 2 DM is the more frequent type of diabetes associated to pregnancy in
Mexican groups; the systematic screening for GDM in normal pregnant women yields
4 to 11% of positivity.
PMID- 9763889
TI - [Quality control of 135 histopathological reports of colo-rectal carcinoma].
AB - OBJECTIVE: To evaluate the information content in our surgical pathology reports
of colon and rectum carcinoma. SETTING: A third level hospital. DESIGN:
Consecutive surgical reports from 1988 to 1994 were retrieved. The gross and
histological variables with prognostic relevance according to the TNM system were
registered using a checklist with standardized variables as proposed by two
groups of pathologists. The adequacy of our reports was surveyed counting the
number of histopathological variables in relation to the 11 prognostic parameters
that must be included in routine surgical reports of large colon carcinomas.
RESULTS: The surgical reports were 135. The histologic type, tumor grade and
histological tumor invasion were provided in most of the reports. In 90% the
lymph node characteristics were described and 85% had gross and histologic margin
assessment. But other variables were poorly informed, i.e. vascular invasion was
informed in one case (0.7%). CONCLUSIONS: Our surgical reports were considered
adequate as 113/135 (84%) recorded more than eight prognostic variables.
Insufficient data were: 1) a poor gross description; 2) lack of tumor grading in
12%; and 3) omission of anatomic site in 29%.
PMID- 9763890
TI - [Four cases of parathyroid cancer].
AB - Parathyroid carcinoma is a rare cause of primary hyperparathyroidism with a
prevalence ranging between 0.5 and 4%. Because of their aggressiveness, prompt
diagnosis and treatment are mandatory. A parathyroid carcinoma was found in four
patients (4.5%) of 88 patients who underwent surgical cervical exploration for
primary hyperparathyroidism at the Institute Nacional de la Nutricion in a period
of seven years. Our paper gives the clinical characteristics, diagnosis,
treatment and outcome of the four patients.
PMID- 9763891
TI - [Giant acinic cell parotid gland adenocarcinoma of the papillary- cystic type].
AB - A case of a 38-year-old male having an acinic cell adenocarcinoma of the parotid
gland is reported. The tumor measured 22 cm and histologically it was of the
papillary-cystic type. The following features were of interest: 1) the tumor size
surpassed the size of previous reported acinic cell adenocarcinomas by 9 cm; and
2) the rarity of its histological variety (cystic papillary) demanded
immunohistochemical and electron microscopic studies to confirm the diagnosis.
PMID- 9763892
TI - [A case of Hallervorden-Spatz disease with magnetic resonance imaging data].
AB - Hallervorden-Spatz disease (HSD) is an uncommon disorder, progressive and
degenerative of the basal ganglia. It begins in the first or second decade of
life and is characterized by a dominant extrapiramidal signs, dystonia and
progressive dementia. It is autosomic recessive, although sporadic cases are seen
in 15%. There is no biological marker for the disease. The post-mortem findings
include iron deposits in the globus pallidum and pars reticulata of the
substantia nigra. Magnetic resonance imaging (MRI) in T2 shows symmetric
hypointense lesions in both globus pallidum with a hyperintense center: giving
the "tiger's eye" sign. This is the first case reported in Mexico of sporadic HSD
with typical clinical and MRI findings.
PMID- 9763893
TI - [Leiomyosarcoma associated with Epstein-Barr virus in an adult with renal
transplant].
AB - Recently the association between the Epstein-Barr virus (EBV) and smooth muscle
lesions has been described in immunosuppressed children but it is infrequent in
adults. The role of EBV in the pathogenesis of these lesions is obscure. We
presents a 28 year old man with end stage renal disease transplanted in 1994. Two
years later he developed several nodular lesions that affected both lungs, liver,
spleen, retroperitoneal ganglia and the left thigh; one year later he died. The
surgical specimen from the thigh and a liver biopsy were diagnosed as
leiomyosarcoma. Immunohistochemical reactions against vimentin and smooth muscle
actin were positive. In situ hybridization disclosed positivity against EBV
nuclear antigens (EBNA-2) in neoplasic cells. This is the first case of sarcoma
in transplanted patients of our institution and represents a rare case of
leiomyosarcoma associated with EBV in adults.
PMID- 9763894
TI - A case of pleomorphic lipoma of the hypopharynx.
AB - We report the first case of pleomorphic lipoma in the hypopharynx. A 69-year-old
man was admitted because of a 12 year history of dysphagia and cough. Direct
laryngo-pharyngoscopy revealed a polypoid, yellow, smooth, submucosal tumor with
well defined borders. At CT scan the tumor showed a hypodense pattern and
measured 3 cm. Microscopically the neoplasm was composed mainly by typical
lipomatous tissue, bundles of collagen and pleomorphic multinucleated cells, some
with floret-like appearance. Lipoblasts and mitoses were not found. Six months
after resection there was no evidence of recurrence.
PMID- 9763895
TI - [New concepts on the physiopathology, diagnosis, and treatment of achalasia].
AB - OBJECTIVES: To review the most relevant publications on the pathophysiology,
clinical manifestations, diagnosis and treatment of esophageal achalasia, and the
clinical experience achieved at our institution in order to propose a practical
strategy to facilitate the management of these patients. DATA SOURCES: Manual and
MEDLINE search of key articles published between January 1986 and July 1997 in
addition to publications of our institute of thirty years. STUDY SELECTION: All
kinds of publications with substantial clinical experience, new information or
research protocols. DATA SYNTHESIS: Achalasia is an uncommon disorder of the
myenteric plexus of the esophagus. Main symptoms are dysphagia, regurgitations
and chest pain. The diagnosis is established by manometric criteria.
Esophagogram, endoscopy and radionuclide esophageal emptying test help to
differentiate other conditions and evaluate the response to treatment.
Pharmacotherapy may provide relief to patients with mild symptoms and is useful
for patients with high risk of complications. Dilations and myotomy are safe,
effective and long lasting procedures. Botulinum toxin may be effective in
selected cases. Predictive factors of response have been described for each
therapy. CONCLUSION: A systematic approach to the management of patients with
achalasia is necessary. Introduction of new therapies as botulinum toxin and
minimal invasion surgery are changing the therapeutic decisions in this field.
Drugs and BoTox are considered the first line of treatment for high risk patients
and dilation and surgery for patients with no risk.
PMID- 9763896
TI - Gene transfer into hematopoietic cells: progress, problems and prospects.
AB - Gene therapy is the introduction of genetic material into somatic cells in order
to correct a genetic defect or provide a new therapeutic function. Among the
numerous potential cellular targets for gene therapy, hematopoietic stem cells
(HSC) may be viewed as one of the best candidates for such genetic modification.
More than 250 clinical gene transfer protocols have been reported from around the
world, and almost one in three involves manipulation of hematopoietic cells. The
introduction of a new gene into the DNA of HSC and expression of the gene product
in their progeny are exciting approaches to treatment of congenital and acquired
diseases. Although it has been shown that hematopoietic progenitor cells, or even
LTC-IC, can be easily transduced with high efficiency by retroviral vectors in
vitro, and that long-term expression and high transduction can be obtained in
mice after transplantation of the gene manipulated cells, this has not been
observed in primate models or in human clinical trials. The reason for this
discrepancy is not properly known. The major problems of gene therapy for cancer
have been transduction rate, selectivity, and effectiveness due to the
heterogeneity of genetic alterations found in human tumors. Overcoming these
limitations in gene therapy requires not only improvement in cell biology and
immunology, but also development of better delivery systems. Nevertheless, gene
therapy is still promising and offers encouragement for future applications in
clinical practice.
PMID- 9763897
TI - Echocardiographic assessment of left and right ventricular diastolic functions in
children with dilated cardiomyopathy.
AB - We evaluated left and right ventricular diastolic functions by pulsed Doppler
echocardiography in 16 children with dilated cardiomyopathy and in 20 healthy age
matched control subjects. The cardiomyopathy group demonstrated an abnormal
relaxation pattern of the left ventricle. In the cardiomyopathy group compared to
normal subjects, peak early filling velocities (43.3 +/- 11 cm/s versus 60.4 +/-
11 cms/s, p < 0.01), the corresponding velocity-time integrals (3.3 +/- 1.4 cm
versus 4.6 +/- 1.2 cm, p < 0.01) and the ratio of peak early filling velocity to
late filling velocity (1.22 +/- 0.47 versus 1.49 +/- 0.23, p < 0.05) were
significantly lower whereas isovolumic relaxation time was significantly longer
(58.9 +/- 19.8 ms versus 49.7 +/- 8.9 ms, p < 0.05). In addition, right
ventricular diastolic filling was also impaired in children with dilated
cardiomyopathy. Peak early filling velocities (41 +/- 7.9 cm/s versus 47.5 +/-
8.8 cm/s, p < 0.05) and the corresponding velocity time integrals (3.0 +/- 1.0 cm
versus 3.87 +/- 1.1 cm, p < 0.05) were significantly decreased, while isovolumic
relaxation time was significantly increased (60.6 +/- 16.3 ms versus 52.2 +/-
12.8 ms, p < 0.05) in the cardiomyopathy group. The study suggests that
abnormalities of both right and left ventricular diastolic function may occur,
and should be searched for, in pediatric patients with dilated cardiomyopathy.
PMID- 9763898
TI - DNA diagnostic tests in Xp21 dystrophy families for prenatal diagnosis.
AB - Duchenne and Becker muscular dystrophies are X-linked genetic disorders
characterized by dystrophin gene defects. We have studied 250 families with
Duchenne and Becker muscular dystrophies (D/BMD) by molecular genetic methods
since 1992. Nineteen exons of the dystrophin gene were analyzed for deletion. In
families with no deletion, linkage analysis was performed to follow the
inheritance of mutant alleles in the affected families. Twenty of these families
requested prenatal diagnosis. Six mothers were found to be non-carriers (99%
accuracy), thus fetuses were examined in the remaining 14. Two fetuses were
affected and terminated. We report our experience and our current clinical
practice in providing prenatal studies for D/BMD.
PMID- 9763899
TI - Pro-inflammatory cytokines, lymphocyte subsets and intravenous immunoglobulin
therapy in Guillain-Barre syndrome.
AB - Both cell-mediated immunity and humoral factors are involved in the pathogenesis
of Guillain-Barre syndrome (GBS). Intravenous immunoglobulin (IVIG) has been
reported to be a practical, effective and safe treatment in childhood GBS,
although the mode of action of IVIG remains uncertain. We studied pro
inflammatory cytokines (interleukin-2, interleukin-1 alpha and tumor necrosis
factor-alpha) in plasma and cerebrospinal fluid (CSF) and lymphocyte subsets in
peripheral blood both in the acute phase and in the recovery period in six
children with GBS treated with IVIG. Flow cytometry was used to determine the
subsets of lymphocytes in peripheral blood, and cytokines analyses were performed
by using ELISA technique. Results were compared with a control group of 20
healthy children. A standard protocol of IVIG (400 mg/kg/day for 5 days) was
administered to all the patients. Plasma interleukin-2 concentrations and the
number of HLA DR+ active T cells in peripheral blood were significantly higher in
the acute phase of the disease than in the recovery period and in healthy
controls. There was no significant difference in the other cytokine
concentrations in plasma and CSF or in the other lymphocyte subsets in peripheral
blood. Our data indicate that IVIG may provide its possible therapeutic effect by
acting in the cell-mediated immunity in GBS patients.
PMID- 9763900
TI - Long-term follow-up of hepatitis B virus carriers with normal transaminases
levels.
AB - There has been very little data recorded on the natural course of chronic
hepatitis B virus infection in asymptomatic children. In order to assess the
natural course of liver disease in hepatitis B surface antigen (HBsAg) carriers
with normal liver tests, 124 such children (81 males, 65.3%) were followed for
six to 144 months (mean 36.8 +/- 22.8 months). Liver tests and hepatitis B virus
(HBV) markers were tested at least every six months. In the beginning, hepatitis
B e antigen (HBeAg) was positive in 61 (53%) of the 115 carriers of HBsAg who
were tested. Anti-HBe was positive in 51 (44.3%), and both HBeAg antigen and anti
HBe were negative in three (2.7%) carriers. The prevalence of HBeAg was not
affected by the patient's age or sex. During follow-up, 11 patients (18%) lost
HBeAg (a mean annual clearance rate of 5.8%), and 12 patients (9.7%) lost HBsAg
(a mean annual clearance rate of 3.1%). We found no difference in the clearance
of HBsAg and HBeAg by age and sex. The presence of another HBsAg positive person
in the family affected HBsAg clearance rate but not HBeAg clearance. Only seven
patients (5 HBeAg positive and 2 anti-HBe positive) developed transient
elevations in liver transaminases. Three of five HBeAg positive children cleared
HBeAg after transaminases elevations. Of the five patients who underwent
percutaneous liver biopsies, non-specific changes were found. It is concluded
that hepatitis B carriers with normal liver tests should be followed with liver
function tests alone and that long-term prognosis is good.
PMID- 9763901
TI - Detection of early anthracycline-induced cardiotoxicity in childhood cancer with
dobutamine stress echocardiography.
AB - Asymptomatic long-term survivors of childhood cancer treated with anthracyclines
may have latent cardiac dysfunction which is undetected by commonly used
echocardiographic methods. A more sensitive echocardiographic screening test,
dobutamine stress echocardiography, was performed on 22 patients (mean age 9.10
+/- 3.79 years) treated with 75 to 450 mg/m2 of anthracyclines (mean 210.45 +/-
127.34) and results were compared with 22 healthy age-matched control subjects.
Echocardiographic Doppler studies were performed after each dobutamine infusion
of 0.5, 2.5, 5 and 10 micrograms/kg/min. Although left ventricular mass was
decreased and end-systolic walls stress increased in the patient group when
compared with the control subjects (p < 0.01 and p < 0.05, respectively), no
differences were found between shortening fraction and ejection force in control
subjects and patients, at rest and during each dobutamine infusion. A decreased
mitral E/A ratio (ratio of early-to-late peak filling velocity) was demonstrated
in anthracycline-treated patients only during dobutamine infusion (p < 0.01). Our
data showed left ventricular diastolic dysfunction during intropic stimulation
with dobutamine, and suggest that dobutamine stress echocardiography is a useful
technique for evaluating the cardiac status of anthracycline-treated patients on
a long-term basis.
PMID- 9763902
TI - Magnetic resonance imaging (MRI) findings in isolated growth hormone deficiency.
AB - In this study the presence of pituitary-hypothalamic abnormalities was searched
by magnetic resonance (MR) imaging in 30 children (18 males and 12 females, aged
7.4 to 23 years) with isolated growth hormone deficiency (IGHD). Small anterior
pituitary was demonstrated in 18 patients and ectopic posterior pituitary (EPP)
in four of them. Pituitary stalk was found to be thin in two patients with
anterior pituitary hypophasia and EPP and was visible only in post-gadolinium
images. In one patient, a hypothalamic mass was found and the bright spot of the
posterior pituitary was found without diabetes insipidus, possibly due to a
variation in the intensity of the bright signal. Eight patients had normal
pituitary imaging suggesting functional damage. In all five patients with
familial growth hormone deficiency the anterior pituitary was hypoplastic. We
conclude that a high percentage of patients with IGHD had anomalies of the
hypothalamo-pituitary region, which could be demonstrated by MR imaging.
Furthermore, the low frequency of perinatal abnormalities in these patients
suggested developmental defect as the cause of the morphostructural
abnormalities. The presence of the familial cases with the same defect pointed to
the genetic origin in some instances.
PMID- 9763903
TI - Plaque radiotherapy in the management of retinoblastoma.
AB - Retinoblastoma is the most common intraocular malignant tumor in childhood and is
radiosensitive. We treated five patients with solitary intraocular retinoblastoma
using iodine-125 plaque radiotherapy as a primary procedure. Tumor basal
diameters ranged from six to 16 mm and thickness ranged from three to 11 mm. The
radiation dose delivered to tumor apex ranged from 3500 to 5000 centigrays. All
tumors regressed considerably within a follow-up ranging between seven to 12
months. There was no tumor recurrence or any complications related to plaque
brachytherapy within this early period. We concluded that plaque radiotherapy is
an effective method in local tumor control and allows eye preservation in
patients with retinoblastoma.
PMID- 9763904
TI - Urinary calcium excretion of children living in the east region of Turkey.
AB - We screened 1647 randomly selected Turkish primary school children to detect the
prevalence of hypercalciuria. Ninety-seven children had hypercalciuria, with a
prevalence of 5.88 percent. Mean Uca/Ucr ratio was 0.135 +/- 0.108; mean Uca/Ucr
value for girls was 0.139 and for boys 0.130 (p > 0.05). Mean Uca/Ucr of boys
with hypercalciuria was 0.341 +/- 0.09 and of girls 0.327 +/- 0.08 (p > 0.05). Of
these 97 children all investigations could be completed in only 40 and these
cases were considered to be idiopathic. Twelve children (21%) had a family
history of consanguinity and 17 (29.8%) of renal stones. The relation between
blood parathormone and Uca/Ucr ratio was not statistically important (p > 0.05).
PMID- 9763905
TI - Peroneal nerve injuries as a complication of injection.
AB - Ten children (8 males, 2 females) diagnosed with peroneal nerve injury as a
complication of injection were included in this study. The age of the children
ranged between four to seven years (mean 6.5 +/- 1.25 years). Physiotherapy and
rehabilitation protocol included superficial heat, neuromuscular electrical
stimulation (either galvanic or faradic current according to the response
elicited), electromyographic biofeedback, exercises (passive, active-assistive
and active), and orthotic support. Before treatment, foot-drop and steppage gait
were observed in all the patients; both were remedied. The post-treatment muscle
strength and electrodiagnostic test results showed statistically significant
improvement when compared with pretreatment values (p < 0.05). We believe that
our relatively favorable results in this study, manifested as shorter recovery
time with no residual deficits, may be related to early intervention with an
extensive physiotherapy program.
PMID- 9763906
TI - The role of PAF and leukotrienes in bioincompatibility of cuprophane membranes in
hemodialysis.
AB - Inflammatory lipid mediators, PAF and leukotrienes (LTs), are thought to have an
important role in biocompatibility in hemodialysis. PAF, LTB4 and LTC4 were
studied both in controls (n: 12) and in 11 children on regular hemodialysis (150
minutes) with cuprophane dialyzers. Blood samples were collected initially (0'
precapillary), at first minute (1'-postcapillary) and at one hour after the
hemodialysis sessions (210'-venous). Presence of LTs and high levels of PAF in 0'
samples compared to levels in controls and significant increases in 1' samples
suggested the alterations in PAF and LTs likely originated from the peripheral
leukocyte activation. In 210' samples, PAF and LTs levels were decreased but
still higher than the levels in 0' samples. This study suggested that PAF and
LTB4 may be the control elements in biocompatibility in hemodialysis with
cuprophane membranes, and demonstrated that the effects of activation last until
the following session.
PMID- 9763907
TI - Intermittent-low dose G-CSF treatment in a patient with chronic neutropenia.
AB - Chronic neutropenia in childhood has many definable causes and thus a clear cause
cannot be identified in a large group of patients. Since the committed stem cell
is involved in this disorder, growth factors such as granulocyte colony
stimulating factor (G-CSF) may play an important role in the treatment of
severely affected children. Because of the side effects and cost, the use of G
CSF should be restricted to a minimum dose. Here we report a child with chronic
neutropenia in whom intermittent-low doses of G-CSF were successfully used over a
long period.
PMID- 9763908
TI - Hydatid cyst mimicking pulmonary hematoma in a patient with hemophilia A.
AB - We present a patient of 2.5 years of age with hemophilia A and a pulmonary
hydatid cyst. A chest x-ray taken by chance showed a paracardiac opacity
resembling an intrapulmonary hematoma which did not reduce in size after
infusions of fresh frozen plasma and factor VIII but rather enlarged.
Transabdominal ultrasound, colored echocardiography, thoracic computed tomography
and magnetic resonance imaging findings were consistent with a cyst that was
firmly attached on the border of the right atrium and also indented it; the wall
was remarkably thick with no internal echoes. Hydatid cyst was diagnosed after
thoracotomy.
PMID- 9763909
TI - Complete atrioventricular heart block in congenital hypothyroidism.
AB - Severe hypothyroidism in children is known to produce cardiac abnormalities such
as asymmetric thickening or hypertrophy of the interventricular septum, smaller
internal dimensions of the left ventricle, a smaller left ventricular outflow
tract, and less systolic septal excursion. In this report, we present a 1.5-year
old boy who was admitted to our hospital because of growth retardation. According
to the clinical and laboratory findings, congenital hypothyroidism, dilated
cardiomyopathy (DCMP), atrioventricular complete heart block and secundum type
atrial septal defect were diagnosed.
PMID- 9763910
TI - Balloon atrial septostomy under echocardiographic guidance. Case report.
AB - A seven-days-old male neonate was transferred to our institution in critically
ill condition. Echocardiographic (ECHO) examination revealed the transposition of
the great arteries (TGA) with a small ventricular septal defect. In the
laboratory examination, arterial oxygen saturation was 29 percent and pH was
7.16. The poor condition of the neonate led us to decide to perform an immediate
bedside balloon atrial septostomy (BAS) in the intensive care unit (ICU) with
ECHO guidance. The umbilical vein was cannulated with a 5 Fr. Miller BAS
catheter. Four balloon passes were performed resulting in large atrial septal
defect. After the procedure, arterial oxygen saturation was measured at 40
percent. In TGA, the baby may present with severe hypoxia and may need management
in the ICU. Emergency BAS may improve the clinical condition of the patient.
Transferring the baby, who is mechanically ventilated (and is in openbed), to the
catheterization laboratory takes time and can be harmful for him, and carries
risk of extubation and heat loss. The limitations of transthoracic ECHO guidance
of BAS include the possibility of a poor ECHO window in an ill neonate on
assisted ventilation and possible interference with maneuverability for both
echocardiographer and catheter operator. It also carries the risk of
contamination of the sterile field. When the advantages and disadvantages of
transthoracic ECHO guidance are considered, transferring the baby to the
catheterization laboratory can cause problems and time loss. Thus, ECHO-guided
BAS at bedside is an efficient and good alternative. The transumbilical approach
may be easier in the first few days of life.
PMID- 9763911
TI - Occult pneumococcal septicemia and pneumococcal pneumonia complicating
pneumatoceles in a previously healthy child.
AB - Fulminating pneumococcal septicemia without an obvious focus of infection is very
rare in previously immunocompetent children older than two years. Furthermore,
pneumatocele formation in pneumococcal pneumonia is uncommon. The majority of
pneumatoceles are self-limited and disappear spontaneously. Here, we report a six
year-old healthy child with occult pneumococcal septicemia and pneumococcal
pneumonia secondary to septicemia. Giant pneumatoceles causing respiratory
insufficiency formed secondary to the pneumococcal pneumonia and were aspirated
via needle under fluoroscopic guidance.
PMID- 9763912
TI - Congenital sialidosis.
AB - Congenital sialidosis is a rare disease resulting from the absence of
neurominidase and presenting with hydrops fetalis, hepatosplenomegaly, dysmorphic
features, vacuolated lymphocytes and extensive vacuolation of the connective
tissue. Elevated levels of sialooligosaccharides in the urine is characteristic.
We describe a newborn baby with congenital sialidosis and discuss the
difficulties in reaching the diagnosis.
PMID- 9763913
TI - Cherubism: a radiological and clinical presentation.
AB - Cherubism is the hereditary form of the fibrous dysplasia of the jaws, but it may
be seen sporadically as well. The disease has a self-limited nature and is rarely
apparent before the age of two. There is no need to interfere surgically with
these lesions of the mandible or the maxilla unless the child is severely
affected, i.e. the disease deteriorates respiration, deglutition, vision, or the
psychiatric makeup of the child due to cosmetic reasons. The clinical
presentation and radiological evaluation of these children are so typical that
the pediatrician and pediatric otolaryngologist need to be informed about this
rarely seen disease. A case of a cherubic child, with his clinical appearance as
well as his radiological evaluation, and discussion about the clinical outcome
are presented.
PMID- 9763914
TI - A case of a four-day-old male with Carpenter's syndrome with transposition of
great arteries.
AB - Carpenter's syndrome (acrocephalopolysyndactyly type II) is an autosomal
recessive syndrome characterized by peculiar facies, synbrachydactyly on fingers
and preaxial polysyndactyly on feet. To our knowledge there are about 40 reported
cases of Carpenter's syndrome in the literature. Congenital heart disease is an
uncommon entity in Carpenter's syndrome. In the case we present, transposition of
great arteries, subpulmonic ventricular septal defect (VSD) and secundum atrial
septal defect (ASD) were diagnosed with echocardiographic examination. Therefore,
a cardiologic examination should be done in every newly diagnosed case of
Carpenter's syndrome for possible heart defect. Early fatality is seen in
Carpenter's syndrome cases associated with congenital heart disease. This is
particularly important from the genetic counselling point of view.
PMID- 9763915
TI - Lupus vulgaris secondary to single BCG vaccination. A case report.
AB - A 10-year-old girl with lupus vulgaris following single BCG vaccination is
reported. She had a 15 x 20 cm painless lesion covering her left shoulder,
axilla, triceps and biceps region. PPD test was positive. Histopathological
picture was identical to lupus vulgaris.
PMID- 9763916
TI - [Focus on intensive therapeutic strategy in type 2-diabetes].
PMID- 9763917
TI - [Leukemia in children].
PMID- 9763918
TI - [Multidisciplinary diagnostics in acute leukemia].
AB - Establishing the exact diagnosis of patients suspected for acute leukemia is of
paramount importance not only for instituting first-line treatment, but also for
prognosticating the patient and determining the status of disease, e.g. in
relation to minimal residual disease. In this overview the most recent
developments regarding the methods for leukaemia diagnosis (cytology, histology,
immunology, cytogenetics and molecular biology) are described and their
respective merits and drawbacks are discussed. Special emphasis is given to the
temporal relationship for application of the methods in the course of disease in
these patients.
PMID- 9763919
TI - [Hypertrophic cardiomyopathy].
AB - Hypertrophic cardiomyopathy is a heterogeneous, progressive disease with a
variable age of debut. Hypertrophic cardiomyopathy is characterized by myocardial
hypertrophy with a bizarre fibre disarray. Angina pectoris, dyspnoea and syncope
are the most frequent symptoms. Hypertrophic cardiomyopathy is an important cause
of sudden death, especially in children and young adults. The aetiology is
genetic in more than 60% of the cases, with an autosomal dominant mode of
inheritance. More than 50 different mutations involving six genes have so far
been associated with the development of hypertrophic cardiomyopathy. These
mutations are located to genes coding for several of the proteins in the cardiac
sarcomere. The protein changes seem to compromise contractility as well as
sarcomere assembly, thereby secondarily causing compensatory hypertrophy. The
management of hypertrophic cardiomyopathy has been markedly improved within the
last few years. This emphasizes the importance of determining prognostic markers
in each patient. A specific genetic diagnosis may prove to be of major
importance.
PMID- 9763920
TI - [Risk factors for epidermoid carcinoma of the vulva].
AB - There is mounting evidence that epidermoid carcinoma of the vulva may be divided
into two aetiologically distinct categories. One category, that is closely linked
to infection with high-risk types of human papillomaviruses, comprises
malignancies whose histological picture is either basaloid or warty carcinoma.
Another category, keratinizing squamous cell carcinoma, has a much weaker
association with human papillomaviruses and occurs mainly in elderly women. This
review describes the current status with regard to risk factors for epidermoid
carcinoma of the vulva.
PMID- 9763921
TI - [Bacteremia in children with acute lymphoblastic leukemia].
AB - The purpose of this study was to describe the pattern of bacterial infections in
children with acute lymphoblastic leukemia. Forty-six children with ALL were
treated for 119 febrile episodes. Antibiotic therapy was initiated with
ampicillin and gentamicin, +/- dicloxacillin and lasted for 5-8 days. Bacterial
cultures were positive in 36 of 119 febrile events. At the beginning of the
febrile disease there was no difference in CRP and neutrophil count between
children with positive and negative blood cultures. The maximum CRP was, however,
significantly higher in children with positive blood cultures. In 75% there was
no need to change the initial antibiotic treatment with ampicillin and gentamicin
+/- dicloxacillin. If the temperature has been normal for 2-3 days and the
neutrophil count is increasing it appears safe to discontinue the antibiotic
therapy after five days when blood cultures are negative and after 7-8 days when
cultures are positive.
PMID- 9763922
TI - [Information to young people about HIV/AIDS and drug abuse. A study of the
knowledge and use of the information material in the youth center in Copenhagen].
AB - A mailed questionnaire was carried out in the city of Copenhagen in which the
leaders of 106 youth centres expressed their opinion on different publications
concerning drug abuse and HIV/AIDS. The knowledge of the publications among the
leaders was less than expected. The last known publication was recognized by 7%
of the leaders, the most well known by 55%. A considerable part of the leaders
stated that they had never received the publications. In centres where the
leaders knew of the publications they were widely used, most often in centres for
older members. A group of leaders stated, that the publications were irrelevant
for members aged 9-14 years. The study points out specific problems in the health
educations process: The publication should aim more specifically at the group and
at subpopulations in the group. The distribution should be secured and the
knowledge of the supply of health education material among the leaders of the
youth centres should be raised.
PMID- 9763923
TI - [Treatment of hypertrophic cardiomyopathy].
AB - The medical management of hypertrophic cardiomyopathy is reviewed. Four cases of
hypertrophic cardiomyopathy are presented, and serve to describe the currently
available invasive treatment modalities, i.e. septal myectomy, dual chamber
pacing, cardioverter defibrillator implantation and heart transplantation. These
different invasive treatments all seem to be symptomatically effective in
carefully selected patients, but studies of prognostic effects are not available.
Finally, new experimental procedures are presented.
PMID- 9763924
TI - [Umbilical cord blood as a biological spare part. Experiences from a pilot
project] at the Fredericia hospital].
AB - The haematopoietic stem cells remaining in the placenta after the umbilical cord
has been cut can substitute for bone marrow in transplantations. It is argued
that these cells should be retrieved and kept frozen as the child's personal
biological spare part. A pilot, population-based collection of cord blood was
carried out in a small provincial in Denmark. It was found that the pregnant
women supported the concept (89%), that the midwives and technicians could carry
out sampling and freezing after a short instruction period, and that the cost of
sampling and storing for 75 years approx. DKK 12,000 per child. The project group
is now seeking partners for further development of the concept.
PMID- 9763925
TI - [Prognosis of hematological patients with relapse following high-dose
chemotherapy and autologous stem cell transplantation].
AB - A retrospective analysis of the outcome for 283 haematological patients who
relapsed after high dose chemotherapy and autologous stem cell transplantation
during a five year period from 1989 to 1994 is presented. The patients were
treated in accordance with local regimes at 20 Nordic transplantation centers and
included patients with acute leukemia (157 patients), multiple myeloma (16
patients) and lymphoma (110 patients). Two hundred and twenty-nine patients with
relapse or progressive disease were given chemo- and/or radiotherapy and the
response was evaluated after 90 days. Fifty-four patients (24%) obtained a
complete remission and 44 patients (19%) partial remission. The overall median
survival after relapse was five months. In the group who received salvage
treatment the median survival was seven months, and for the 54 patients in
complete remission the median survival was 15 months. We found that survival
after relapse depends upon primary disease, the time from transplantation to
relapse and whether salvage therapy was initiated.
PMID- 9763926
TI - [Mortality of anorexia nervosa in Denmark 1970-1987].
AB - Eight hundred and fifty-three patients were admitted to psychiatric institutions
in Denmark with anorexia nervosa between 1970 and 1986. Based on register
information, 50 deaths were recorded during a mean follow-up period of 7.8 years.
Amongst these, five were males and 45 females. The standardized mortality ratio
(SMR) was 9.1 in both sexes. The SMR was maximal during the first year after
index admission. Suicide was the dominant cause of death amongst subjects who
died from unnatural causes (18 of 22 cases). Among those who died from natural
causes (24 subjects), 13 individuals died from anorexia nervosa, and 11
individuals died from other illnesses.
PMID- 9763927
TI - [Amebiasis--a differential diagnosis from inflammatory bowel disease].
AB - Entamoeba histolytica is a very uncommon etiology of travelers diarrhoea, but may
be an important differential diagnosis to inflammatory bowel disease. A
misdiagnosis of amoebic colitis as inflammatory bowel disease followed by
inadvertent treatment with corticosteroids may be fatal. Current techniques for
the diagnosis of amoebiasis include stool studies, endoscopic biopsy and
serology. Demonstration of haematophagous trophozoites in feces or in tissue
biopsy is the definitive method for diagnosis. Unfortunately both methods have
many drawbacks. If the specimens are negative, serology can support the diagnosis
especially in a non-endemic area where a positive test is highly predictive of
current disease.
PMID- 9763928
TI - [Contact eczema caused by pine wood].
AB - A 34 year-old woman, working with pine wood treated with sodium hydroxide and
pyrogallol, developed dermatitis on arms, face and neck. Patch testing showed
allergic reaction to colophony and pine wood, but not to sodium hydroxide or
pyrogallol. Pine wood contains colophony. Since avoiding pine wood, she has had
no further attack of dermatitis.
PMID- 9763929
TI - [Malignant transformation of Recklinghausen disease in the small intestine].
AB - Neurofibromatosis is a relatively common genetic disorder of the peripheral and
central nervous systems. Benign or malignant tumours may occur in different
organs. Visceral tumours arising in the neural plexus of the intestinal wall may
cause ulceration, bleeding, obstruction, perforation and palpable abdominal
masses. In this paper a case of chronic anaemia due to a chronically bleeding
intestinal neurofibroma is presented in a woman who had undergone intestinal
resection. Histopathological analysis showed a neurofibroma with malignant
transformation and a liver metastasis.
PMID- 9763930
TI - [Quality is more important than structure].
PMID- 9763931
TI - Legionnaires' disease in Europe, 1997.
PMID- 9763933
TI - Antituberculosis drug resistance worldwide.
PMID- 9763932
TI - Murine typhus, Portugal.
PMID- 9763934
TI - RABNET-strengthening international surveillance of human and animal rabies.
PMID- 9763935
TI - Dengue in the WHO Western Pacific Region.
PMID- 9763936
TI - Aseptic meningitis due to echovirus 30, Japan, 1997-1998.
PMID- 9763937
TI - A fight on our hands.
PMID- 9763938
TI - Invisible women.
PMID- 9763939
TI - Helping Asian women to understand the menopause.
AB - Language barriers and cultural differences isolate Asian women from the facts
concerning menopause and HRT. Zubeda Sarwar discusses the results of a study set
up to address these issues.
PMID- 9763940
TI - Detecting and preventing postnatal depression.
AB - Usually only a quarter of postnatal depression cases are identified. Jo Borrill
discusses the role of nurses in detecting depression in mothers and giving them
support.
PMID- 9763941
TI - Coping with common catheter care problems.
PMID- 9763942
TI - Nurses' involvement in the care of children with eczema.
PMID- 9763943
TI - Giving advice on HRT: a closer look at your role.
PMID- 9763944
TI - Traveller's diarrhoea.
PMID- 9763945
TI - The role of protocols in enhancing nursing care.
PMID- 9763946
TI - Delivering pressure sore care in the community.
PMID- 9763947
TI - The correct use of low-adherent dressings.
PMID- 9763948
TI - Going Dutch on health care.
PMID- 9763949
TI - Strike while the iron's hot.
PMID- 9763950
TI - Twilight zones.
PMID- 9763951
TI - A fast service from nurses.
PMID- 9763952
TI - Vitamins and health: the role of a balanced diet.
PMID- 9763953
TI - Using spirometers: taking a blow for good health.
PMID- 9763954
TI - Prostate disease: expanding the nurse's role.
PMID- 9763955
TI - Remedies for athlete's foot.
PMID- 9763956
TI - Approaches to managing diabetes in Asian people.
AB - The prevalence of diabetes is four times higher in people of Asian origin than in
Caucasians. Mary Burden discusses how the management of diabetes differs in
Asians.
PMID- 9763957
TI - Hepatitis: reducing the risks.
PMID- 9763958
TI - Why nurse prescribing is good for you....
PMID- 9763959
TI - Leg ulcers: finding solutions to common problems.
PMID- 9763960
TI - Deodorising dressings for malodorous wounds.
PMID- 9763961
TI - It'll be all right on the night....
PMID- 9763962
TI - Let's focus on the real issues.
PMID- 9763963
TI - Harsh cuts.
PMID- 9763964
TI - Phobias: when the fear just gets too much.
PMID- 9763965
TI - Role of allergies in eczema.
AB - Contact allergies have an important role to play in eczema. Justine Ratcliffe
considers how detection of the causative allergen by patch testing can improve
disease management
PMID- 9763966
TI - Contraception: let's put men in the picture.
PMID- 9763967
TI - A cover-up operation to target sunseekers.
AB - Although the link between sun and skin cancer is well known, many people still
ignore this fact in the pursuit of a 'healthy' tan. Jackie Cresswell highlights
the dangers and looks at the risks.
PMID- 9763968
TI - Urinary tract infections: the hidden cause.
AB - Urinary infections are a common problem mainly affecting women. Deborah Rigby
outlines their causes and symptoms, and describes how they can be avoided.
PMID- 9763969
TI - Group protocols and the law.
PMID- 9763970
TI - Methods of effective pain management in adults.
PMID- 9763971
TI - The orf virus: a disease of the farming community.
PMID- 9763972
TI - Reaping the benefits of foam dressings.
PMID- 9763973
TI - Setting up a stoma care service.
PMID- 9763974
TI - A force to be reckoned with.
PMID- 9763975
TI - Landmarks in diabetes care: a historical perspective.
AB - Since the discovery and isolation of insulin in 1921, many advances in diabetes
research and management have been made. Funda Suleyman charts the successes over
the years.
PMID- 9763976
TI - Strategies to promote healthier eating.
PMID- 9763977
TI - A new treatment option in asthma management.
AB - For the first time in 20 years a new therapeutic option in asthma management has
emerged. Christine Fehrenbach discusses the role of leukotriene receptor
antagonists in asthma care.
PMID- 9763978
TI - The NHS--taking a look back.
PMID- 9763979
TI - Vaccines: the role of the NHS.
PMID- 9763980
TI - Pushing back the boundaries: administration of medicines.
PMID- 9763981
TI - The dying art of bandaging.
PMID- 9763982
TI - Role of swabbing in wound infection management.
PMID- 9763983
TI - Targeting teenage asthmatics.
PMID- 9763984
TI - A timely booster.
PMID- 9763985
TI - A positive effect.
PMID- 9763986
TI - Impact of osteoporosis on quality of life.
AB - Osteoporosis is now a major public health problem that affects men as well as
women, resulting in pain, bone fractures and premature death. Anne Sutcliffe
explains the nurse's role in treatment and prevention.
PMID- 9763987
TI - Dealing with nocturnal enuresis in children.
PMID- 9763988
TI - Helping people to remain in control of their psoriasis.
AB - The impact of psoriasis on the quality of life cannot be overestimated. Jane
Watts outlines the various forms of this skin condition and describes the nurse's
role in its management.
PMID- 9763989
TI - Screening for diabetes: how to make a diagnosis.
AB - The classification of diabetes into different types is not always
straightforward. Mary Burden explains the role of screening procedures in making
an effective diagnosis.
PMID- 9763990
TI - Nutrition and wound healing.
PMID- 9763991
TI - When to use film dressings.
PMID- 9763992
TI - Good health through nutrition.
PMID- 9763993
TI - Medication management in residents of aged care facilities.
AB - Responding to the medication needs of an ageing population is a major challenge
for the Australian health care system. As the main care givers of residents in
aged care facilities, nurses are ideally positioned to promote quality medication
management for these individuals. This review paper identifies issues affecting
medication management of elderly residents, using the psychotropic family of
drugs as an example. Strategies aimed at improving medication management in
elderly residents, which include education, guidelines documents, legislation and
consumer medication information, are also examined. While the review explores the
nurse's perspective, it also emphasises the need for collaborative involvement.
PMID- 9763994
TI - National palliative care education and training needs analysis.
AB - This purpose of this research study was to conduct a needs analysis for the
education and training of palliative care providers. The research methodology was
a descriptive survey of the education and training needs of palliative care
providers. A total of 1848 questionnaires was distributed to the palliative care
providers throughout Australia and a return rate of 34 per cent (627) was
attained. The responses from Australia metropolitan areas totalled 51.7 per cent
and those from Australian rural and remote areas totalled 48.3 per cent (302).
The results showed that the specific education and training needs, as identified
by the palliative care providers, included pain management, loss and grief, drug
therapies, education updates and other needs. Deficiencies of current education
and training programs in palliative care included cost as most postgraduate
courses are not HECs funded but are offered as full fee-paying courses. Travel
and distance were reported as the most prohibitive aspect to attending a
palliative care course. The content in existing palliative care programs
predominantly focused on providing care in a palliative care unit or a respite
setting. More emphasis needs to be placed on caring for patients in their home; a
shift from death in the hospital to death in the home.
PMID- 9763995
TI - A conceptual framework for nursing management of pain.
AB - The development of specific nursing-based conceptual frameworks help to define
and link ideas when performing studies involving a number of different concepts.
Through the use of nursing models and frameworks, knowledge gained from nursing
research can be more readily disseminated into nursing practice. The present
framework encompasses nurses' knowledge and attitudes about pain management and
incorporates the work of many theorists, the most prominent being that of Brenda
Conrad. This pain management scheme expresses the belief that nurses have a
unique and pivotal role in supporting and promoting optimum health states and
providing quality life. It generates overall goals related to nurse assistance of
the patient in the areas of recovery, independence, adjustment and treatment, and
emphasises that to meet the patient's needs, nurses must possess adequate pain
assessment and management knowledge as well as supportive attitudes to provide
efficient quality care provision. The major supposition emphasised throughout
this conceptual framework is that underlying nursing care is a grounded knowledge
base fostering genuine care and concern for the welfare of the holistic patient.
PMID- 9763996
TI - Non-compliance or client control?
PMID- 9763997
TI - Undergraduate Clinical Practicum and the opportunity to practice skills in
preparation for the graduate year: a review of the literature.
AB - Clinical Practicum is an important component of undergraduate nursing education,
in order to prepare the graduates for their role as Registered Nurses. It is
argued by some that in reality the Clinical Practicum experiences do not
adequately provide graduates with the skills they need during the graduate year.
PMID- 9763998
TI - The 'write advice' or 'how to get a journal article published'.
AB - This paper was written in response to a perceived increase in nurses' interest in
writing for publication in nursing journals. It provides essential information
for inexperienced or 'beginning' writers. Who should write for publication, what
should be written for publication and how it should be written are discussed.
Practical details with respect to writing and rewriting are included.
PMID- 9763999
TI - Fact sheets on the Web: a case study of the on-line dissemination of information
on the anti-infective properties of breast milk.
AB - As the World Wide Web expands, it is beginning to take on a new role as a
publishing medium for authoritative encyclopaedic information. This development
is likely to impact the way in which many professionals work--improving their
access to up-to-date information on the one hand, while enabling their clients to
be much better informed on the other. This article draws on the experience gained
from publishing a small, specialised Web site providing information on the anti
infective properties of human breast milk. It describes the way in which the Web
site came into being, the nature and structure of the information that is
provided, and the types of responses the site has received. The article concludes
with a discussion of the ways in which the availability of authoritative
information on the Web is likely to impact the future roles of health
professionals.
PMID- 9764000
TI - Learning with technology: use of case-based physical and computer simulations in
professional education.
AB - This paper describes a multimedia technology project in midwifery education and
how it is being developed to improve student learning experiences and outcomes.
The role of the university providing quality education relevant to today's world
and professional practice is emphasised. A collaborative (Royal Melbourne
Institute of Technology and Australian Catholic University) interdisciplinary
project 'Pregnancy Simulator: Developing and Enhancing Student Learning of
Pregnancy Assessment Skills' was developed with university and direct
Commonwealth support. This project consists of a physical simulation of a
pregnant woman at term and case-based multimedia computer simulations designed to
develop and enhance student learning of abdominal assessment skills. A key
feature of the development has been to design a learning experience explicitly on
an authoritative theory-based view of teaching, in this case Diana Laurillard's
'Conversational Framework'.
PMID- 9764001
TI - On nursing's 'reflective madness'.
PMID- 9764002
TI - Exploring women's experiences: the critical relationship between nursing
education, peer mentoring and female friendship.
AB - A research study was conducted in 1995 with seven women nurses from Southern
Cross University, Australia. The aim of this research was to investigate the
possible relationship between female friendship, mentoring and nursing education.
The researchers comprised six second-year nursing degree students and the
programme co-ordinator for the Bachelor of Nursing programme. This research was
framed in an emancipatory paradigm of critical social science and feminist
theory. Reflective journalising and interviewing were used as the research
methods. The results indicated that there is an inextricable link between female
friendship and peer mentoring. These two 'features' created a productive climate
for shared learning, shared caring, reciprocity and commitment to one another's
personal and professional growth.
PMID- 9764003
TI - Nurses as patient-teachers: exploring current expressions of the role.
AB - An exploration of nursing literature reveals a broad acceptance of the role of
patient-teacher. While patient-teaching has become widely accepted as part of
nursing practice, there is little published evidence to support an assertion of
its centrality in current nursing practice. Patient-teaching has been variously
described, yet there is evidence of polarity in its construction. This polarity
is between a health promotion empowerment framework and a mechanistic
interventionist framework. Further, there is little visible consensus about the
scope and boundaries of patient-teaching by nurses. Preliminary findings from a
pilot study of nurses' perceptions of patient-teaching reveal tensions created
within these contradictory frameworks. Nurses find themselves positioned as
paternalistic in their approach to patients and simultaneously subservient to
other disciplines in determining the focus of patient-teaching.
PMID- 9764004
TI - Massage as a nursing intervention: using reflection to achieve change in
practice.
AB - The process of reflection can be used by nurse educators to more fully understand
the nature of nursing practice and to actively use that understanding to bring
about change through education. This paper documents a process of reflection
carried out by a nurse educator within an action research project. The project
was intended to assist palliative care nurses to learn the skill of massage and
successfully integrate this therapy into their practice. Reflection takes place
before the action to achieve change is implemented, in order to identify factors
which will affect the development and implementation of the project. The
reflection includes discussion of methodological issues, consideration of the
influence of massage and holism in nursing practice and the influence of practice
and institutional factors on palliative care nursing.
PMID- 9764005
TI - Caring by degrees.
AB - Caring is synonymous with nursing and, regardless of the culture, race, lifestyle
or sexuality of clients, nurses should care for all clients. However, the
emergence of HIV/AIDS brought a new and quite different challenge to nurses with
regard to willingness to care. Some nurses expressed a negative attitude toward,
and reluctance to care for, those clients with HIV/AIDS, mainly due to fear of
contagion based on ignorance about the disease. The purpose of this cross
sectional study was firstly to determine if there were differences in attitudes
toward caring for clients with HIV/AIDS in the three different at-risk groups
(homosexuals, intravenous drug users and haemophiliacs), as expressed by nursing
students at the beginning (Semester 1) and at the end (Semester 7) of a three-and
a-half-year nursing degree programme. The second determination was whether or not
there were differences between the two groups of students regarding their
knowledge of HIV/AIDS. Data results indicated no significant difference between
the two groups of students in regard to caring attitude towards members of the at
risk groups and knowledge of AIDS. This paper discusses the implications of the
research findings for nursing and further research.
PMID- 9764006
TI - Dilemmas in nursing care: a student's reflection of a critical incident.
AB - A student nurse will face many questions when they are confronted with the death
of a patient. In this paper, a first-year nursing student reflects upon the death
of a young adult (Yvonne) as part of a nursing inquiry subject. The author
reflects upon the death of Yvonne and re-examines the questions and responses
that this critical incident raised.
PMID- 9764007
TI - Learning with technology: use of case-based physical and computer simulations in
professional education.
AB - This presentation will clarify contemporary ideas on the role of technology in
education and how it can be employed to improve student learning experiences and
outcomes. The paper will emphasise RMIT's role in providing quality education
that is relevant to today's world and professional practice. It will examine a
specific collaborative (RMIT & ACU), interdisciplinary project 'Pregnancy
Simulator: Developing and Enhancing Student Learning of Assessment Skills'. This
project consist of a physical pregnancy model connected to a multi-media computer
assisted learning package for the purpose of enhancing student learning of
abdominal assessment skills. Our paper outlines an innovative technology-based
teaching project and includes current educational issues or problems encountered
in professional education, steps already taken to address these difficulties and
how this project intends to facilitate learning. It identifies expected learning
outcomes for midwives, nurses and medical students, and examines pedagogical
principles applied to technological applications designed to provide guided
discovery for allowing students to build confidence and competence in
professional education. The case-based physical and computer simulations
contextualise learning to assist transfer of learning to real world situations.
This paper will also discuss how technology-based projects can be evaluated and
integrated into university curricula to enhance student learning.
PMID- 9764008
TI - Should nurses act legally or ethically?
AB - Should health professionals act legally or ethically in the delivery of health
care presuming it is impossible to do both? There is a tendency by some to take
the position that to act ethically is more important in the provision of health
care and to ignore or at least minimise any legal consequences that may arise. At
the same time the law may ignore ethical principles claiming the legal position
is more important. This article argues that while law and ethics are both
important in the delivery of health care the law as the final arbitrator takes
precedence.
PMID- 9764009
TI - Acute renal failure. Focus on advances in acute tubular necrosis.
AB - This article has reviewed the most recent thoughts and findings on the
pathophysiology and care of ARF. Clearly, we still have much to learn, but an
updated practitioner is necessary in order to meet the challenges of this complex
disease, as we search for tomorrow's answers.
PMID- 9764010
TI - Continuous renal replacement therapy. A national perspective AACN/NKF.
AB - Health care providers rely on quality continuing education programs to increase
their knowledge and to acquire new skills. Participation in programs such as
CVVH: Implications for Clinical Practice-the Patient, the Circuit, the Team can
potentially improve patient outcomes. While this study identifies critical care
nurses as a receptive professional group for further CRRT training, it also
indicates that additional education in this topic may benefit other members of
the critical care team as well. Therefore, because the critical care nurse's
role, while crucial to the clinical management of patients undergoing CRRT, does
not include prescribing or initiating CRRT therapy, it is difficult to predict
the impact of future workshops on the increased and sustained use of CRRT in
critical care arenas. If you would like additional information on CVVH:
Implications for Practice-the Patient, the Circuit, the Team, please contact the
National Kidney Foundation at (800) 622-9010, or the American Association of
Critical Care Nurses at (800) 899-2226.
PMID- 9764011
TI - CAVH. Principles and practical applications.
AB - While being one of the earliest and simplest forms of continuous renal
replacement therapy, CAVH provided a means for treating the azotemic,
hypervolemic critically ill patient. In order to deliver care for the patient
undergoing CAVH, critical care nurses must demonstrate an understanding of the
physiologic mechanism of action as well as knowledge and technical competency
regarding circuit management. Multidisciplinary standards are imperative for
successful implementation of any CRRT program. Any institution wishing to adopt
certain CAVH standards provided within this article should review each particular
standard to determine if it meets the specific needs of their unique patient
population.
PMID- 9764012
TI - CAVHD. Transitioning from CAVH.
PMID- 9764013
TI - Adult/pediatric CVVH. The pump, the patient, the circuit.
PMID- 9764014
TI - Applications in continuous venous to venous hemofiltration. Interactive case
studies in the adult patient.
PMID- 9764015
TI - Applications in continuous venous to venous hemofiltration. Interactive pediatric
case study.
PMID- 9764016
TI - Continuous venous to venous hemofiltration. Implementing and maintaining a
program: examples and alternatives.
PMID- 9764017
TI - Setting up a continuous venovenous hemofiltration educational program. A case
study in program development.
AB - The key to developing a successful CVVH course is the involvement of the clinical
experts--the staff nurses. It is an ongoing process that requires continual
improvement. The CVVH course will help to assure the competency of the ICU nurse
in caring for the critically ill patient on CVVH.
PMID- 9764018
TI - Ethical decision making. Models for the dialysis dependent patient.
PMID- 9764019
TI - Care management in a managed care world.
PMID- 9764020
TI - Service use patterns in HIV/AIDS case management: a five-year study.
AB - Over the course of the HIV/AIDS epidemic, the profile of the client population
has changed. Increasingly, individuals infected with HIV identify injection drug
use and heterosexual contact as their risk factors. Additionally, women are
increasingly affected by the epidemic. This study examines individuals enrolled
in an HIV/AIDS case management program over a 5-year period. Although the number
of clients served per year remained relatively stable, the number of clients with
injection drug use histories and the percentage of women on the caseload have
increased consistently. The percentage of clients requiring services and the
amount of services used increased in the areas of attendant care, mental health
services, and skilled nursing care. Additionally, the annual mean use of services
increased in the areas of in-home supportive services and hours of case
management. These data suggest that as individuals receiving HIV/AIDS case
management services are found to have complicating social and economic factors,
their need and use of services will increase.
PMID- 9764021
TI - Case management and supported employment: a good fit.
AB - Individuals with severe disabilities have often been denied the full range of
vocational opportunities. Because of discrimination and oppression, and false
beliefs regarding their skills, capacities, capabilities, and interests,
individuals with disabilities have often been relegated to nonwork activities or
sheltered work opportunities. Passage of legislation, such as the Developmental
Disabilities Assistance and Bill of Rights Act of 1984 and Title VI, Part C of
the Rehabilitation Act Amendments of 1986, in combination with systems change
grants funded through Title III of the Rehabilitation Act, provided the basis for
the initiation of a series of federal- and state-funded demonstration projects
designed to provide opportunities and supports for individuals with severe or
significant disabilities to work at competitive sites in the community. This
model of vocational services, called supported employment, while initially
conceived as a vocational program for individuals with mental retardation, has
been modified to successfully provide services to individuals with mental
illness, acquired brain injury, autism, cerebral palsy, physical disabilities,
and other disabilities. A key to the success of these programs is the
complementary working relationship between the case manager and the job coach.
While there may be some overlap in what each brings to the person with a
disability, each professional plays distinctive and critical roles in the
carrying out of supported employment.
PMID- 9764022
TI - Designing an automated services tracking system for a caregiver support program.
AB - This article describes the process of developing an automated services tracking
system for California's 11 regional Caregiver Resource Centers. The system was
designed over a 3-year period for use by social workers, administrative
personnel, and managers and has implications for both internal services
monitoring and state reporting functions. The system development included input
from clinical staff to be user-friendly to nontechnical staff. The article
recounts technical and conceptual obstacles overcome and the evaluation of a
relatively modest idea into a sophisticated, custom-made computer program. Issues
of start-up, implementation, expansion, and report design are discussed. Lessons
learned and other insights have practice and policy implications for documenting
and reporting service usage at case management and other social services
agencies. Lastly, an overview of the system's features and highlights of
automated reports are provided.
PMID- 9764023
TI - Giving and receiving social supports for elderly mentally ill people.
AB - Two research questions were addressed in this study of 57 older adult outpatients
diagnosed with schizophrenia and 37 older adults attending a senior citizen's
center with no significant medical or psychological problems. The research
questions were: (a) Are there gender-based differences in giving and receiving
expressive and instrumental social supports for chronically mentally ill
patients? (b) Do chronically mentally ill elderly patients differ from older
adults without chronic mental illness in giving and receiving expressive and
instrumental social supports? Based on a two-factor multi variate analysis of
variance, women, with or without diagnosis of chronic mental illness, were more
likely than were men to provide emotionally close social contacts with others, as
well as to give advice to and receive advice from others. However, there were no
differences in giving or receiving instrumental or expressive social supports
based on whether or not the respondent was receiving outpatient psychiatric
services for a chronic mental illness. In view of this, the possibility that the
mentally ill have more to offer in relationships than is generally assumed is
discussed. Suggestions for future research and implications for case managers
also are discussed.
PMID- 9764024
TI - Case management for the baby boom generation: a strengths perspective.
AB - To understand the challenges and opportunities for case management as the turn of
the century approaches, we must consider the 76 million individuals born between
1946 and 1964, commonly referred to as the baby boom generation. This article
examines the baby boom generation in the context of planning effective case
management services. The generation's strengths are highlighted to suggest how
case management systems can meet the anticipated service needs of baby boomers as
they age.
PMID- 9764025
TI - An empirical study of nursing in patients undergoing two different procedures for
abdominal aortic aneurysm repair.
AB - Specialized vascular nursing has to meet the challenge presented through progress
and modern developments in vascular surgery. Endovascular techniques are becoming
more widespread and are now available for diseases that previously have required
extensive surgery. A comparative study was carried out in two groups of patients
with infrarenal abdominal aortic aneurysms (N = 50), either by means of the
traditional open surgical approach or by the new endovascular stented graft
technology. Four problems were compared in both groups of patients: (1) length of
hospital stay, (2) dependency on nursing, (3) patients mobility after surgery,
and (4) analgesic requirements. Data were obtained from a designated data sheet.
Analysis of the data obtained helped us in our service to optimize the nursing
process for patients undergoing major aortic surgery for open, as well as
endovascular, procedures, especially regarding the nursing anamnesis and nursing
diagnosis.
PMID- 9764026
TI - Polytetrafluoroethylene femorodistal grafts: can the use of a vein collar offer
patients a reasonable chance of success?
AB - The growing number of patients with critical ischemia who lack a suitable
autogenous vein for grafting pose a particular problem for the vascular team. In
such patients the use of a polytetrafluoroethylene graft with a distal
anastomotic vein cuff or patch has been advocated as an alternative to primary
amputation. The use of such adjunctive techniques is reviewed through a 3-year
retrospective study of 50 patients under the care of one surgeon. Data analyzed
include patient demographics, risk factors, and presenting symptoms. All patients
were included in a Duplex graft surveillance program. The cumulative patency
rates at 1 and 2 years were 56% and 55%, respectively, with limb salvage rates of
85% and 80%. The data support a reconstructive approach to maintain the quality
of the patient's life.
PMID- 9764027
TI - Experience with a new human skin equivalent for healing venous leg ulcers.
AB - Leg ulcers affect about 650,000 adults each year and in every setting--rural,
urban, and both economically developed and impoverished areas. Both the physical
and the psychologic aspects of treatment present challenges to the caregiver. The
nurse must be aware of new techniques for treatment and be able to educate
patients about potential modalities for healing. A human skin equivalent,
Apligraf, will soon be available for treatment of these wounds. The results of
controlled, multicenter studies indicate that human skin equivalent interacts
with the patient's own cells, responds to individual wound characteristics, and
promotes healing. The nursing professional can readily master the application
technique and will find that this tissue-engineered skin product offers a new
approach to wound management.
PMID- 9764028
TI - Impact of telephone reinforcement of risk reduction education on patient
compliance.
AB - Smoking and hyperlipidemia are key risk factors resulting in peripheral arterial
disease. These risk factors can be reduced when appropriate lifestyle changes are
made, especially for patients less than 60 years of age. Therefore patient
education regarding smoking cessation and healthy diet changes may positively
impact the course of disease. The ability to make a lifestyle change is affected
by (1) an individual's belief that his or her behavior affects the condition and
(2) the social support received from family, especially a primary caregiver. This
pilot study compared two randomized groups of patients with peripheral arterial
disease for a 1-year period. The control group received the standardized teaching
plan regarding smoking cessation and diet at the postoperative clinic visit. The
experimental group received the standardized teaching plan in addition to
quarterly telephone calls to reinforce smoking cessation and diet information. At
the end of 1 year, both groups received follow-up telephone calls at the
conclusion of the study for endpoint data collection. Specifically, this project
investigated the following research statements: (1) Patients who receive periodic
telephone follow-up will have greater compliance with the recommendations
regarding smoking and diet than those who do not receive follow-up. (2) Patients
whose caregivers are compliant with the recommendations regarding smoking
cessation and diet will have significantly higher compliance themselves. The data
were analyzed by using cross tabulation, sign test, and McNemar's test for
nonparametric data to measure mobility, overall perception of health, knowledge
of risk reduction information, and compliance with the smoking cessation and low
fat/cholesterol diet plan. The results of this pilot study revealed no
significant differences between the control and experimental groups. Telephone
reinforcement was not sufficient in this study to influence lifestyle change.
However, standardized teaching improved diet scores in both groups. Differences
were found between smokers and nonsmokers.
PMID- 9764029
TI - United Kingdom guidelines for the management of acute pancreatitis. British
Society of Gastroenterology.
PMID- 9764030
TI - Bacterial factors and immune pathogenesis in Helicobacter pylori infection.
AB - Virulent Helicobacter pylori strains which have been clinically associated with
severe outcome induce increased gastric mucosal immune responses. Although
several bacterial pathogenic factors have been shown to have a considerable role
in H pylori infection, variability in host immune responses may also contribute
to mucosal damage in H pylori associated gastritis.
PMID- 9764031
TI - Helicobacter pylori: the size of the problem.
PMID- 9764032
TI - Management of Helicobacter pylori infection in children.
AB - When trying to decide which children with Helicobacter pylori infection should be
treated and at what stage they should be tested, we should take into account the
fact that eradication of the infection may be useful both to induce symptom
remission and to prevent later complications in adulthood. However, well designed
studies to identify those infected children who are at risk of developing
complications or have symptoms due to the infection are still lacking. Current
literature only gives information on how to treat children with H pylori
infection. Treatment regimens that include two drugs are usually more effective
than in adults, and produce an eradication rate of 70-80%, but they should be
given for at least two weeks, shorter treatments being less effective. Antibiotic
resistance can impair eradication rate and the frequency of resistant strains in
children should be studied. Combinations of antibiotics with antisecretory drugs
are highly effective in adults, but triple therapy with two antibiotics and an
antisecretory drug has been seldom tried in children; compliance is often poor so
that the eradication rate is often similar to that produced by dual therapy.
Compliance strongly influences eradication, and short simple treatment regimens
that produce rapid symptom remission with few side effects are needed to optimise
patient compliance. After treatment, eradication must be proved. Serological
tests can help, provided that pretreatment serum is available and three to six
months have passed since the treatment. A 13C-ureabreath test (13C-UBT) should be
performed at least six weeks after treatment, but false negative results can
occur and cut-off must be adjusted.
PMID- 9764034
TI - Management of dyspeptic patients by general practitioners and specialists.
PMID- 9764033
TI - Different management for Helicobacter pylori positive and negative patients with
gastro-oesophageal reflux disease?
AB - Available evidence would suggest that Helicobacter pylori infection does not
contribute to the pathogenesis of gastro-oesophageal reflux disease. The
prevalence of H pylori infection in patients with reflux disease is no greater
than that in control populations. There are some data suggesting that the
organism has a protective role: patients with duodenal ulcers develop reflux
disease after H pylori eradication, whereas in patients with oesophageal reflux
those with H pylori infection have less severe reflux changes. There is also
evidence indicating that the presence of H pylori augments the anti-secretory
properties of both the H2 receptor antagonists and proton pump inhibitors (PPIs),
suggesting that eradication therapy may not be beneficial. However, the
considerable recent interest in the association between H pylori and reflux
disease has largely been generated by studies outlining the interactions between
H pylori infection and acid suppression in the long term. In H pylori positive
patients, therapy with PPIs is associated with a proximal extension of the
infection and its associated gastritis. In addition long term PPI therapy is
reported to be associated with an accelerated development of atrophic gastritis,
suggesting that H pylori should be diagnosed and treated. Although these latter
findings in particular need confirmation, H pylori eradication therapy should be
considered in this patient group, at least until there is evidence to the
contrary.
PMID- 9764035
TI - Treatment of Helicobacter pylori infection: management of patients with ulcer
disease by general practitioners and gastroenterologists.
AB - Knowledge of the importance of Helicobacter pylori infection is still
fragmentary. Currently only a minority of patients with ulcers receive adequate
eradication therapy. Ideally there should be no difference in the level of
knowledge between general practitioners and gastroenterologists. Yet in practice
there is a substantial difference. The results obtained in highly selected
clinical trials do not reflect results of practice in the real world. The gap can
only be narrowed through careful mass education. The role of testing for H pylori
infection in primary care practice needs to be clarified and the problem of
erratic treatment by general practitioners and specialists needs to be resolved.
Adequate response to these problems will require the creation of "regional
platforms" where both primary care physicians and specialists decide on empirical
therapy, eradication strategy and referral of dyspeptic patients.
PMID- 9764037
TI - Helicobacter pylori: the gastric cancer problem.
PMID- 9764036
TI - Importance of changes in epithelial cell turnover during Helicobacter pylori
infection in gastric carcinogenesis.
AB - The role of Helicobacter pylori in gastric carcinogenesis is supported almost
exclusively by epidemiological data and prospective histopathological studies.
From biological and molecular points of view, there is no evidence that H pylori
or its cytotoxic products have any mutagenic effects. Nevertheless, this
infection is associated with profound changes in the pattern of epithelial cell
turnover in gastric glands, though the importance of these changes in gastric
carcinogenesis is still controversial. H pylori infection increases cell
proliferation and alters the distribution of cycling cells within these glands,
but these changes can be reversed by successful eradication of the infection.
Apoptosis seems to be increased in gastric epithelial cells during H pylori
infection, as shown by in vitro studies. There is some, though no conclusive,
evidence that this finding also occurs in H pylori positive subjects. It seems
that cagA status influences the effect of H pylori on epithelial apoptosis in
infected patients. An association of in vitro H pylori induced apoptosis with
changes in the expression of pro- and anti-apoptotic genes is reported in the
literature, but further study is necessary to clarify the effect of H pylori
infection on the molecular events of the apoptotic pathway.
PMID- 9764038
TI - Acid suppression and gastric atrophy: sifting fact from fiction.
AB - Prolonged pharmacological acid suppression is associated with various
histological changes in the gastric mucosa, particularly in Helicobacter pylori
infected patients. In a number of subjects these changes include a shift in the
gastric inflammation from the antrum to the corpus. This finding has been
interpreted as gastric atrophy, and the possibility that acid suppression
accelerates the progress of lesions that may lead to gastric cancer has been
considered. Two recent studies on the relation between treatment with proton pump
inhibitors and atrophic gastritis have yielded apparently contradictory results.
These studies are reviewed in detail here and some of the possible reasons for
the discrepant conclusions are explored. In particular, the way the terms
"gastric atrophy" and "atrophic gastritis" are used is examined critically.
PMID- 9764040
TI - Urea breath tests in the management of Helicobacter pylori infection.
AB - The 13/14C-Urea breath test (UBT) is based on the simple principle that a
solution of isotopically labelled urea will be rapidly hydrolysed by the
abundantly expressed urease of H pylori. The released 13/14CO2 is absorbed across
the mucus layer to the gastric mucosa and hence, via the systemic circulation,
excreted in the expired breath. Distribution of urea throughout the stomach
prevents sampling error and allows semiquantitative assessments of the extent of
H pylori infection. Originally the 13C-UBT was complex, cumbersome and costly
but, by simplifying the protocol and reducing the number of samples to be
analysed, is now a much easier, quicker and cheaper test for detecting H pylori.
Although mass spectrometry is needed for analysis of exhaled 13CO2, the use of
the stable isotope, which is completely safe, provides advantages over the 14C
UBT using radioactive 14C-urea, such that it can be used in women and children
and a user's licence is not required. The widespread availability of scintigraphy
for 14CO2 analysis may make the 14C-UBT seem an attractive alternative to the 13C
UBT. However, there are no standard protocols for the 14C-UBT and although the
methods are similar, several different cut off values are used which makes formal
validation studies still necessary. Both tests are easy to perform with minimum
opportunity for observer variation or methodological error; they are very
sensitive and specific tests and provide a clinical "gold standard" against which
the accuracy of other tests can be validated. The 13/14C-UBT detects only current
infection and can be used to screen for H pylori infection and as the sole method
for assessing eradication. In addition, because the 13C-UBT can be performed
repeatedly in the same subject, it can be used to monitor the effects of novel
anti-H pylori therapies and for epidemiological studies in children.
PMID- 9764039
TI - Blood tests in the management of Helicobacter pylori infection. Italian
Helicobacter pylori Study Group.
AB - There are three main types of blood test available for the management of
Helicobacter pylori infection: those that detect an antibody response; tests of
the pathophysiological state of the stomach; and those that indicate an active
infection. Enzyme linked immunosorbent assay (ELISA) based kits are the most
numerous of the commercially available tests. Originally the kits used crude
antigen preparations but many of the newer kits use a more purified antigen
preparation giving increased specificity but a lower sensitivity. The
sensitivity, specificity, and predictive values of the tests can also be affected
by the population under test and coexistent disease in the patients. Near patient
test kits are based on either latex agglutination or immunochromatography.
Generally, they have low sensitivities compared with laboratory tests. Commercial
western blotting kits have also been developed and are used to detect the
presence of specific virulence markers. The exact role of serology in the
management of Helicobacter infection has still to be defined, although there is
evidence that, used as a screening procedure, it can reduce endoscopy cost and
workload. Gastrin and pepsinogen blood concentrations may provide valuable
information on the pathophysiological state of the stomach--for example, the
presence of inflammation or gastric atrophy. A combination of serology and serum
concentrations of gastrin and pepsinogen may be used effectively to detect
serious gastroduodenal disease in patients.
PMID- 9764041
TI - Any role left for invasive tests? Histology in clinical practice.
PMID- 9764042
TI - The life and death of Helicobacter pylori.
AB - The ability of Helicobacter pylori to survive in the varying acidity of the
stomach is considered to be linked to its ability to maintain a tolerable pH in
its periplasmic space by acid dependent activation of internal urease activity.
Whereas survival of H pylori can occur between a periplasmic pH of 4.0 to 8.0,
growth can only occur between a periplasmic pH of 6.0 to 8.0. When urease
activity is only able to elevate periplasmic pH to between 4.0 and 6.0, the
organisms will survive but not divide. In the absence of division, antibiotics
such as clarithromycin and amoxycillin are ineffective. Proton pump inhibitors,
by elevating gastric pH, would increase the population of dividing organisms and
hence synergise with these antibiotics.
PMID- 9764043
TI - Clinical relevance of resistant strains of Helicobacter pylori: a review of
current data.
AB - Acquired resistance of Helicobacter pylori to metronidazole and clarithromycin
has been reported, with metronidazole resistance being very common. This has an
important clinical impact on dual therapies, as well as on the standard triple
therapies. However, when antisecretory drug based triple therapies with
amoxycillin or clarithromycin and metronidazole are used, the resistance can be
overcome in up to 75% of the cases in most of the studies. Clarithromycin seems
to be a better choice than amoxycillin to achieve this goal. Nevertheless,
resistance to metronidazole remains a risk factor for treatment failure. The most
precise information comes from studies in which minimum inhibitory concentrations
(MICs) are reported as well as whether the strain is susceptible or resistant.
Few data are available from clinical trials to measure the impact of
clarithromycin resistance. However, such resistance seems to have a negative
impact on the clinical outcome of treatment. It is of greater importance that H
pylori resistance is closely monitored in the future.
PMID- 9764044
TI - The European meeting on Helicobacter pylori: therapeutic news from Lisbon.
AB - The current standard of Helicobacter pylori treatment has been confirmed by the
studies presented at the Lisbon workshop--that is, one of three one week proton
pump inhibitor (PPI) based triple therapies comprising a twice daily standard
dose of a PPI in combination with two of the following antimicrobial agents:
clarithromycin, amoxycillin, or a nitromidazole. This standard of treatment is
also highly efficacious and cost-effective in routine community practice. The
current data confirm the equivalence of ranitidine bismuth citrate to PPI, and of
azithromycin to clarithromycin. The optimum dose for azithromycin has not yet
been defined. There is some evidence that in certain regions treatment for more
than one week may be advantageous. The reasons are still not clear. However,
microbial resistance may be one important factor, as it has a substantial effect
on treatment outcome and the prevalence of resistance varies considerably in
different areas. The negative impact of resistance is increased by shortening the
treatment time. At present, there is no general necessity to test for resistance
before treatment. However, before selection of a second line treatment, testing
for resistance is recommended.
PMID- 9764045
TI - Treatment of Helicobacter pylori: future therapeutic and prophylactic
perspectives.
AB - Helicobacter is one of the most widespread, chronic infections in the world and
causes a serious disease with a significant mortality. The organism is difficult
to eradicate using antibiotic therapy and to date no vaccine is available for use
in humans. The most successful treatments comprise acid suppression in
combination with two antibiotics and a series of seven day courses will reliably
cure around 85% of infected individuals. Further modifications of these regimens
via the introduction of newer and more effective antibiotics and acid
suppressants may enable the treatment to be simplified, made more effective and
cause fewer side effects. However, the major challenge is to develop a specific
monotherapy targeted against Helicobacter pylori. The H pylori genome has now
been sequenced and this provides an opportunity both to identify specific targets
for drug therapy, and to facilitate the identification and production of antigens
that may be helpful in manufacturing a vaccine. This paper discusses the future
of helicobacter therapy and vaccination.
PMID- 9764046
TI - Arterial or venous conduits for redo coronary artery bypass grafting?
PMID- 9764047
TI - Heparin for coronary angioplasty: high dose, low dose, or no dose?
PMID- 9764048
TI - Digitalis and strophanthus--cardiac glycosides.
PMID- 9764049
TI - Angiotensin II receptor antagonists for heart failure.
PMID- 9764050
TI - False aneurysm of the left ventricle.
PMID- 9764051
TI - Long-term results of reoperations for recurrent angina with internal mammary
artery versus saphenous vein grafts.
AB - OBJECTIVE: To evaluate the long term results of coronary reoperations for
recurrent angina with internal mammary (thoracic) arteries versus vein grafts.
DESIGN: Inception cohort of 103 patients with a mean follow up of 7.1 years
(range 1.0-11.6). SETTING: Regional cardiothoracic centre. PATIENTS: Among 103
consecutive patients, mean (SD) age 61.8 (9.7) years, who were reoperated for
recurrent angina between January 1982 and December 1991, 53 patients had
unilateral or bilateral internal mammary artery (IMA) grafting supplemented or
not with saphenous vein (SV) grafts (group A), and 50 patients underwent
reoperative coronary surgery using SV grafts only (group B). The two groups were
comparable in terms of demographic and clinicopathological data. MEASUREMENTS AND
RESULTS: Operative mortality was 5.6% (95% confidence interval 4.6 to 6.6) for
group A, and 10% (8.2 to 11.8) for group B (p > 0.05). Probability of freedom
from new recurrence of angina was 86% at 5 and 10 years in group A, compared with
56% and 25% respectively in group B (p = 0.005). Freedom from cardiac events was
estimated to be 81% at 5 and 10 years in group A, v 52% and 20% for group B,
respectively. Actuarial survival was 95% v 93% at 3 years, 95% v 85% at 5 years,
and 88% v 71% at 10 years after reoperation (p > 0.05). CONCLUSIONS: The long
term results of IMA are superior to SV grafts in terms of freedom from new
recurrence of angina and other cardiac events. The IMA is thus the conduit of
choice in coronary revascularisation.
PMID- 9764052
TI - Recent activation of the plaque immune response in coronary lesions underlying
acute coronary syndromes.
AB - OBJECTIVE: To discriminate between chronic inflammation and acute activation of
the plaque immune response in culprit lesions of patients with acute coronary
syndromes. DESIGN: Retrospective study. SETTING: Tertiary referral centre.
SUBJECTS: 71 patients having coronary atherectomy were classified according to
their ischaemic syndrome: stable angina (n = 23); stabilised unstable angina (n =
18); refractory unstable angina (n = 11); and acute myocardial infarction (n =
19). MAIN OUTCOME MEASURES: Immunohistochemical measurement of interleukin 2
receptor (IL-2R) (CD25) positive cells expressed as a percentage of the total
amount of (CD3 positive) T lymphocytes in frozen sections of atherectomy
specimens. RESULTS: The number of lesions containing IL-2R (CD25) positive T
cells increased with severity of the ischaemic coronary syndrome (stable angina,
52%; stabilised unstable angina, 77.8%; refractory unstable angina, 90.9%; acute
myocardial infarction, 89.4%). The percentage of activated T cells (CD25/CD3
ratios x100) increased in lesions associated with refractory unstable angina
(7.8%) and acute myocardial infarction (18.5%), compared with those in lesions
associated with either chronic stable angina (2.2%) or stabilised unstable angina
(3.3%). CONCLUSIONS: An increase in the percentage of IL-2R positive T
lymphocytes in culprit lesions of patients with acute coronary syndromes
indicates recent activation and amplification of the immune response within
plaques. This may result in a burst of inflammatory products with tissue
degrading and vasoactive properties and, hence, could initiate or accelerate the
onset of an acute coronary event.
PMID- 9764053
TI - Histological patterns of atherosclerotic plaques in unstable angina patients vary
according to clinical presentation.
AB - BACKGROUND: Unstable angina is a heterogeneous clinical syndrome. The diverse
clinical presentations of unstable angina may reflect different pathogenic
mechanisms within the plaque. OBJECTIVE: To investigate the cellular constituents
of culprit coronary atheromatous plaques in patients with stable angina pectoris
and patients with diverse clinical presentations of unstable angina. METHODS: 48
patients who underwent coronary atherectomy for management of ischaemic heart
disease: 23 had stable angina and 25 had unstable angina. Of the latter, 11
patients were classified as Braunwald's IIB and 14 as Braunwald's IIIB unstable
angina. The presence of thrombus, cholesterol clefts, and smooth muscle cell
proliferation was assessed in atherectomy samples using standard histological
techniques. Monoclonal antibodies were used to identify smooth muscle cells and
macrophages within atherosclerotic plaque fragments. RESULTS: Fresh thrombus was
more frequently found in patients with Braunwald's IIIB unstable angina (64%)
than in patients with stable angina (22%) or IIB unstable angina (27%) (p <
0.0006). A pattern of smooth muscle cell proliferation ("accelerated progression
pattern") was observed which was also associated with coronary thrombus. This
pattern was present in 30% of patients with stable angina, 64% of patients with
IIIB unstable angina, and in all patients (100%) with IIB unstable angina.
Atherosclerotic plaques with thrombus, cholesterol clefts, and macrophages were
more common in patients with unstable angina than in stable angina patients.
CONCLUSION: The presence of a specific smooth muscle cell proliferation
(accelerated progression) pattern in patients with unstable angina, particularly
in those with Braunwald's IIB unstable angina, suggests that episodic plaque
disruption and subsequent healing may be an important mechanism underlying angina
symptoms in these patients.
PMID- 9764054
TI - Can C reactive protein or troponins T and I predict outcome in patients with
intractable unstable angina?
AB - OBJECTIVE: To determine whether a single blood test for the measurement of C
reactive protein, or troponin I or T concentrations could be used to stratify
patients with intractable unstable angina awaiting transfer for coronary
angiography by correlating these values with coronary anatomy and transient
myocardial ischaemia. DESIGN: Prospective study. SETTING: Tertiary cardiac unit.
PATIENTS: All patients admitted to their local hospital with ischaemic chest
pain, uncontrolled by medical treatment, in whom acute myocardial infarction had
been excluded by serial measurement of creatine kinase and lack of Q waves on
ECG. INTERVENTION: Coronary angiography and ST segment monitoring for 24 hours.
MAIN OUTCOME MEASURES: Concentrations of C reactive protein, troponins T and I,
coronary anatomy, presence of transient myocardial ischaemia. RESULTS: Median C
reactive protein, troponin I, and troponin T concentrations were 17.1 mg/dl (4.8
to 203.9), 0.05 microgram/l (0 to 7.8), and 0.0 microgram/l (0 to 2.51),
respectively. Seven patients (10%) had normal coronaries and 14, 20, and 31 had
one, two, or three vessel coronary disease, respectively. Nineteen (26%) had
transient myocardial ischaemia, 33 (46%) had complex lesion morphology, and six
(8%) had intracoronary thrombus. Of the three markers, troponin T alone was
higher in patients with multivessel disease (p < 0.05) and in those with
transient myocardial ischaemia (p < 0.05), but there was no significant relation
between C reactive protein, troponin T or I and lesion morphology or thrombus.
CONCLUSIONS: In patients transferred to a tertiary centre with intractable chest
pain, C reactive protein and troponin I are not predictive of transient
myocardial ischaemia or lesion morphology, both of which are surrogate markers of
outcome. Troponin T is, however, raised in patients with multivessel disease or
transient myocardial ischaemia. These serum protein assays cannot be used to
stratify the risk of patients with unstable angina who are awaiting transfer to
the tertiary centre.
PMID- 9764055
TI - Relation between the kinetics of thallium-201 in myocardial scintigraphy and
myocardial metabolism in patients with acute myocardial infarction.
AB - OBJECTIVE: To investigate the relations between myocardial metabolism and the
kinetics of thallium-201 in myocardial scintigraphy. METHODS: 46 patients within
six weeks after the onset of acute myocardial infarction underwent resting
myocardial dual isotope, single acquisition, single photon emission computed
tomography (SPECT) using radioiodinated 15-iodophenyl 3-methyl pentadecaenoic
acid (BMIPP) and thallium-201, exercise thallium-201 SPECT, and positron emission
tomography (PET) using nitrogen-13 ammonia (NH3) and [F18]fluorodeoxyglucose
(FDG) under fasting conditions. The left ventricle was divided into nine
segments, and the severity of defects was assessed visually. RESULTS: In the
resting SPECT, less BMIPP uptake than thallium-201 uptake was observed in all of
40 segments with reverse redistribution of thallium-201, and in 21 of 88 segments
with a fixed defect of thallium-201 (p < 0.0001); and more FDG uptake than NH3
uptake (NH3-FDG mismatch) was observed in 35 of 40 segments with reverse
redistribution and in 38 of 88 segments with fixed defect (p < 0.0001). Less
BMIPP uptake in the resting SPECT was observed in 49 of 54 segments with slow
stress redistribution in exercise SPECT, and in nine of 17 segments with rapid
stress redistribution (p < 0.0005); NH3-FDG mismatch was observed in 42 of 54
segments with slow stress redistribution and in five of 17 segments with rapid
stress redistribution (p < 0.0005). CONCLUSIONS: Thallium-201 myocardial
scintigraphy provides information about not only myocardial perfusion and
viability but also about myocardial metabolism in patients with acute myocardial
infarction.
PMID- 9764056
TI - Low molecular weight heparin as an adjunct to thrombolysis for acute myocardial
infarction: the FATIMA study. Fraxiparin Anticoagulant Therapy in Myocardial
Infarction Study Amsterdam (FATIMA) Study Group.
AB - OBJECTIVE: To investigate the feasibility of fixed dose, weight adjusted
subcutaneous low molecular weight heparin (LMWH), with monitoring of anti-Xa
levels and assessment of coronary patency rates after three to five days, thereby
giving an initial indication of its safety and efficacy. DESIGN: In 30 patients
with acute myocardial infarction, LMWH (nadroparine) was given as a body weight
adjusted intravenous bolus with thrombolysis (rt-PA infusion) and in weight
adjusted subcutaneous doses at six hours, and every 12 hours thereafter for 72
hours. The target range was defined prospectively as 0.35-0.70 anti-factor Xa
activity (aXa) units. The aXa level was measured every six hours. Coronary
angiography was performed in all patients within five days after the start of
thrombolytic treatment to determine patency (TIMI 2 and 3 flow) of the infarct
related artery. RESULTS: The mean (SEM) aXa level over 72 hours was 0.52 (0.08)
U/ml; from 12 hours onwards 88% of all aXa measurements were within the target
range. At angiography, a patent infarct related artery was present in 24 of the
30 patients. No major bleeding complications occurred, though minor bleeding
complications were observed in two patients. CONCLUSIONS: This small study
indicates that LMWH is feasible as an adjunct to thrombolysis in patients with
acute myocardial infarction. The aXa levels were within the target range and
patency rates at three to five days were around 80%, with no major bleeding
complications.
PMID- 9764057
TI - Coronary event and case fatality rates in an English population: results of the
Oxford myocardial infarction incidence study. The Oxford Myocardial Infarction
Incidence Study Group.
AB - OBJECTIVES: To determine coronary event and case fatality rates in an English
population aged less than 80 years in Oxfordshire, and to compare these rates
with those reported by the UK monitoring trends and determinants of
cardiovascular disease (MONICA) centres in Scotland and Northern Ireland and
those ascertained in Oxfordshire in 1966-67. DESIGN: A population wide
surveillance study conducted in 1994-95 using prospective and retrospective case
ascertainment. SETTING: A resident population in Oxfordshire of 568,800.
SUBJECTS: Patients with suspected myocardial infarction or coronary death.
OUTCOME MEASURES: A diagnosis of definite or possible myocardial infarction or
coronary death using WHO MONICA diagnostic criteria based on symptoms,
electrocardiograms, cardiac enzymes, necropsy findings, and past medical history.
RESULTS: The annual rate for a first or recurrent coronary event per 100,000
population aged less than 65 years in 1994-95 was 273 for men and 66 for women
after age adjustment to a standard world population. Rates in the age group 65-79
years were 1350 for men and 677 for women. Between 1966-67 and 1994-95, the age
standardised event rate in the age group 30-69 years decreased significantly by
33% (95% confidence interval (CI) 44 to 21) in men, and there was a non
significant reduction of 8% (95% CI -33 to 17) in women. The age standardised 28
day case fatality rates also decreased significantly by 28% (95% CI 41 to 15) in
men and by 32% (95% CI 55 to 9) in women. CONCLUSIONS: The coronary event rate in
Oxfordshire was much lower than rates reported by MONICA centres in Glasgow and
Belfast, and similar to rates reported by MONICA centres in France and northern
Italy. The substantially lower event rate accounts for lower coronary heart
disease mortality in Oxfordshire than in Scotland and Northern Ireland. The
reduced coronary mortality in this region is attributable to declines in coronary
event and case fatality rates.
PMID- 9764058
TI - Beta adrenergic blockers lower renin in patients treated with ACE inhibitors and
diuretics.
AB - OBJECTIVE: To examine the effect of concomitant intake of beta blockers with
angiotensin converting enzyme (ACE) inhibitors, diuretics, or both on plasma
renin concentrations in a population based sample (MONICA survey, Augsburg,
Germany). SUBJECT AND METHODS: 728 individuals were studied, of whom 171 were
treated using monotherapy (ACE inhibitor (n = 21), diuretic (n = 10), or beta
blocker (n = 72)), or combination treatment (ACE inhibitor + diuretic (n = 32),
ACE inhibitor + beta blocker (n = 7), diuretic + beta blocker (n = 22), ACE
inhibitor + diuretic + beta blocker (n = 7)). The remaining 557 individuals were
untreated. Indications for treatment were hypertension (75%), coronary artery
disease with (12%) or without (3%) hypertension, or unknown (10%). RESULTS: Mean
(SEM) renin concentrations in individuals treated with an ACE inhibitor (41 (8)
mU/l), a diuretic (41 (10) mU/l), or the combination of an ACE inhibitor and a
diuretic (54 (10) mU/l) were raised compared with untreated individuals (17 (1)
mU/l; p < 0.05 each). Monotherapy with a beta blocker, however, decreased mean
renin concentrations (12 (1) mU/l; p < 0.01 v untreated). Renin concentrations in
individuals taking a beta blocker with either an ACE inhibitor (21 (8) mU/l), or
a diuretic (22 (4) mU/l), or with both an ACE inhibitor and a diuretic (21 (7)
mU/L), were significantly lower compared with renin concentrations in groups not
receiving beta blocker treatment (p < 0.05 each). CONCLUSION: These data suggest
that the upregulation of renin by treatment with ACE inhibitors, diuretics, or
both can be largely prevented by concomitant beta blocker treatment.
PMID- 9764059
TI - Transcatheter coil occlusion of residual interatrial communications after Fontan
procedure.
AB - OBJECTIVE: To assess the use of detachable coils as an alternative method to
occlude interatrial communications after Fontan operations. DESIGN: Descriptive
clinical study of selected patients after Fontan operation with interatrial
communications inappropriate for transcatheter umbrella occlusion. SETTING:
Tertiary paediatric cardiac referral centre. PATIENTS: Seven patients after
Fontan operation with residual interatrial communications of various types
producing a right to left shunt. INTERVENTIONS: Transcatheter placement of
detachable coils with a diameter of 3 or 5 mm within the interatrial
communication. RESULTS: A total of 14 coils were successfully placed within
persistent patent fenestrations of the interatrial baffle, residual leaks at the
suture line between the patch material and the right atrial wall, and unusual
venous interatrial communications. The mean (SD) aortic oxygen saturation
increased from 88 (1.1)% (range 86-89%) to 92 (1.3)% (range, 89-93%; p < 0.001)
and the mean (SD) right atrial pressure rose from 9.7 (2) mm Hg (range, 6-11) to
10.6 (2.4) mm Hg (range, 6-13; p < 0.05) after coil implantation. In five
patients, complete obliteration of the interatrial shunt was shown by angiography
after coil implantation. At a mean (SD) follow up of 10 (4) months (range, 3-15)
a residual interatrial shunt was detected by Doppler colour echocardiography in
only one patient, and oxygen saturations ranged from 90% to 95% (mean, 92%).
There were no late coil embolisations, thromboembolic events, or haemolysis in
any patient. CONCLUSIONS: Detachable coils can be used successfully to occlude
residual interatrial communications after the Fontan procedure. In selected
cases, in whom intended transcatheter umbrella occlusion of residual interatrial
leaks is not possible, the use of detachable coils might offer a safe alternative
method to eliminate interatrial right to left shunting after the Fontan
procedure.
PMID- 9764060
TI - Extending the limits of transcatheter closure of atrial septal defects with the
double umbrella device (CardioSEAL).
AB - OBJECTIVE: To report initial findings from a selected group of patients with
morphological variations of the atrial septal defect who underwent transcatheter
closure with a second generation redesigned double umbrella device. PATIENTS: Two
patients with abnormal location of the oval fossa and partial deficiency of the
septal rim, three patients with multiple defects, and two patients with a
multiperforated aneurysm of the interatrial septum (age range, 3.6-25.5 years).
METHODS: Defects were closed with the double umbrella device (CardioSEAL)
consisting of two sets of flexible arms (with central and two mid-arm hinges)
covered with sewn Dacron patches. The implantation procedure was monitored by
transoesophageal echocardiography. RESULTS: The diameter of the defect measured
during transoesophageal echocardiography ranged from 7-18 mm and the balloon
stretched diameter ranged from 13-21 mm. The size of the devices varied from 28
33 mm and the ratio of device size to defect size varied from 1.6-2.1. Two
devices (23 and 28 mm) were chosen in a patient with two separated defects. No
complications or serious arrhythmias were observed during implantation or follow
up (median, 1.8 months). Residual shunting was trivial in three patients and mild
in one patient (inferiorly located additional defect). CONCLUSIONS: To extend the
selection critera of an isolated central interatrial defect for transcatheter
closure, some modifications of the implantation technique are needed. Using the
redesigned double umbrella device, effective closure in patients with multiple or
irregularly shaped atrial septal defects was achieved, indicating a broadening of
the spectrum of transcatheter closure.
PMID- 9764061
TI - Right sided intracardiac thrombus.
PMID- 9764062
TI - Cardiopulmonary responses to exercise in patients with hypertrophic
cardiomyopathy.
AB - OBJECTIVE: To examine the submaximal and maximal indices of the exercise response
of patients with hypertrophic cardiomyopathy. DESIGN AND SETTING: Prospective
examination of cardiopulmonary responses to ramp exercise test of a consecutive
group of patients with hypertrophic cardiomyopathy attending a cardiomyopathy
outpatient clinic. METHODS: 50 patients aged 12 to 76 years (mean (SD) 35 (14))
with diagnosis of hypertrophic cardiomyopathy performed incremental cycle
ergometry; 22 sedentary volunteers (seven female, 15 male) aged 14 to 58 years
(mean (SD) 31 (12)) served as controls. Respiratory gas was continuously sampled
from the mouth-piece, and its concentration profile phase aligned to the respired
air flow signals. Following analogue to digital conversion, gas exchange
variables were computed breath by breath and the data were averaged every 30
seconds for graphic display. A 12 lead ECG was monitored continuously and
recorded every three minutes during the exercise. RESULTS: Both the peak oxygen
uptake attained on the test (VO2 peak) and anaerobic threshold were reduced in
patients with hypertrophic cardiomyopathy compared with the control group (p <
0.0001). In 29 patients (59%) the VO2 peak was less than 60% and only two
patients achieved a peak above 80% of their predicted values. The anaerobic
threshold was below 60% of the predicted value in 31 patients and above 80% in
only three patients. The slope of oxygen uptake/work rate relation (delta
VO2/delta WR) was decreased in 16 patients (32%). The maximum oxygen pulse
(VO2/HR) was reduced as a percentage of the predicted value, and became flat at
high work rates in 32 patients. There was a significant correlation between
anaerobic threshold and VO2 peak (p < 0.0001), work efficiency (p < 0.0001), and
maximum oxygen pulse (p < 0.0001). The slope of change in ventilation against
change in carbon dioxide output (delta VE/delta VCO2) for the subanaerobic
threshold range was increased in 36 patients (72%) and was inversely correlated
with anaerobic threshold (p < 0.0002). CONCLUSIONS: There were severe
abnormalities in maximal and submaximal indices of pulmonary gas exchange in a
cohort of hypertrophic cardiomyopathy patients attending a referral
cardiovascular clinic. The pattern of the abnormalities suggests that a reduced
stroke volume response, ventilation/perfusion mismatch, and abnormal peripheral
oxygen utilisation are the possible mechanisms of exercise intolerance.
PMID- 9764063
TI - Potential impact of antiarrhythmic drugs versus implantable defibrillators on the
management of ventricular arrhythmias: the Midlands trial of empirical amiodarone
versus electrophysiologically guided intervention and cardioverter implant
registry data.
AB - BACKGROUND: Survival was prolonged in selected patients with sustained
ventricular arrhythmias who received implantable cardioverter defibrillators
(ICDs) in the antiarrhythmics versus implantable defibrillators (AVID) study. The
Midlands trial of empirical amiodarone versus electrophysiologically guided
intervention and cardioverter implant in ventricular arrhythmias (MAVERIC)
registry is a population based trial. OBJECTIVE: To determine the number of
patients who satisfy the AVID criteria because of the high cost of ICDs. DESIGN:
Observational study, based on a continuing trial. SETTING: All coronary care
units in the Midlands region in the United Kingdom (population 9.1 million).
PATIENTS: Patients presenting to a coronary care unit with sustained ventricular
arrhythmias not related to an acute myocardial infarction are entered onto the
registry. Those who consent to the MAVERIC study are randomised to receive either
empirical amiodarone or electrophysiologically guided treatment. Demographic
data, details of clinical presentation, and echocardiographic findings are
collected. These data have been used to calculate the number of patients who
satisfy the AVID criteria and would benefit from ICD implantation. The financial
implications have been calculated for the region and nationally. RESULTS: 132
patients were entered onto the registry during the first five months of the
MAVERIC study; 69 patients fulfilled the AVID criteria. Extrapolation of these
data over a 12 month period suggests implantation of at least 166 new ICDs
(compared with 23 implants in 1996). This would increase the UK ICD implant rate
from five to at least 18 per million of the population, costing the National
Health Service 24.1 Pounds million per annum. CONCLUSION: Application of the AVID
criteria in the UK will cause a great increase in the ICD implant rate, with
serious financial implications.
PMID- 9764064
TI - Autonomic modulation of the atrial cycle length by the head up tilt test: non
invasive evaluation in patients with chronic atrial fibrillation.
AB - OBJECTIVE: To determine the effects of upright posture compared with supine
position on the dominant atrial cycle length (DACL) in patients with chronic
atrial fibrillation. DESIGN: The power/frequency spectrum of QRST suppressed lead
V1 ECG was studied in 14 patients in the supine position and during the head up
tilt table test. The DACL changes were compared with changes in heart rate and
blood pressure. RESULTS: Compared with the supine position, the upright position
reduced the DACL from 160 to 150 ms (p < 0.01). The DACL was increased after
returning to the supine position from the upright position, from 147 to 154 ms (p
< 0.01). Heart rate increased from 91 beats/min in the supine position to 106 in
the upright position (p < 0.01). There was a decrease in heart rate from 109
beats/min in the upright position to 93 after returning to the supine position (p
< 0.01). No significant changes were seen in systolic or diastolic blood
pressure. There were indications of an inverse relation between DACL and heart
rate when comparing the supine position before and after tilt with the upright
position (p < 0.001). CONCLUSIONS: The sympathetic stimulation and vagal
withdrawal induced by rising to upright body position are associated with a
decrease in DACL during chronic atrial fibrillation. Thus a reflex increase in
sympathetic discharge after induction of atrial fibrillation could favour the
persistence of the arrhythmia.
PMID- 9764065
TI - Dispersion of QT and QTc interval in healthy children, and effects of sinus
arrhythmia on QT dispersion.
AB - OBJECTIVE: To determine the normal values of QT and QTc dispersion and the
effects of sinus arrhythmia on QT dispersion in healthy children. PATIENTS AND
SETTING: The study was carried out in a university hospital on 372 local
schoolchildren (200 male, 172 female), aged seven to 18 years. METHODS: The QT
and preceding RR intervals of at least one sinus beat were measured manually in a
range of nine to 12 leads on standard 12 lead surface ECGs. The corrected QT
interval was computed by the method of Bazett. Dispersion of QT and QTc were
defined as (1) the difference between the maximum and minimum QT and QTc
intervals occurring in any of the 12 leads (QTD and QTcD), (2) the standard
deviation of the QT and QTc interval in the measurable leads (QT-SD and QTc-SD).
RESULTS: There was no significant difference in QT, QTc, and RR dispersion
between girls and boys. Overall 53% of children had sinus arrhythmia. Although
QTD and QT-SD were not affected by sinus arrhythmia, both QTcD and QTc-SD were
significantly greater in children with sinus arrhythmia than in those without
(QTcD: 52.9 (17.4) v 40.9 (13.1); QTc-SD: 17.5 (5.9) v 13.2 (4.0); p < 0.001).
CONCLUSIONS: As calculation of QTc dispersion is affected by sinus arrhythmia,
which is common in childhood, we suggest that QT dispersion should not be
corrected for heart rate in children.
PMID- 9764066
TI - New electrocardiographic criteria for the differentiation between
counterclockwise and clockwise atrial flutter: correlation with
electrophysiological study and radiofrequency catheter ablation.
AB - OBJECTIVE: To develop new electrocardiographic (ECG) criteria for the
differentiation between counterclockwise and clockwise atrial flutters.
BACKGROUND: Traditionally, the ECG differentiation between counterclockwise and
clockwise atrial flutters is based on the flutter wave polarity in the inferior
leads. However, determination of flutter wave polarity is subjective and
sometimes difficult, especially in flutter waves of undulating pattern. PATIENTS:
The study comprised 37 consecutive patients with drug resistant atrial flutter;
30 had counterclockwise and 17 had clockwise atrial flutter (10 had both forms of
atrial flutter). The isthmus dependence was confirmed by entrainment study and
catheter ablation. The ECG patterns of both types of atrial flutter were compared
and the flutter wave polarity in the inferior leads was determined by four
independent cardiologists. RESULTS: The flutter wave polarity in the inferior
leads appeared negative in 24, positive in one, and equivocal in five of the
counterclockwise atrial flutters; polarity appeared negative in one, positive in
10, and equivocal in six of the clockwise atrial flutters. However, the aVF/lead
I flutter wave amplitude ratio was > 2.5 in all counterclockwise but < 2.5 in all
clockwise atrial flutters. The flutter wave nadirs in the inferior leads
corresponded to the upstrokes in V1 in all counterclockwise atrial flutters, but
corresponded to the downstrokes in V1 in all clockwise atrial flutters.
CONCLUSIONS: The flutter wave polarity in the inferior leads does not correlate
well with the flutter wave rotating direction. However, counterclockwise and
clockwise atrial flutters can be differentiated by new ECG criteria with high
accuracy.
PMID- 9764067
TI - Spontaneously terminating ventricular fibrillation and asystole induced by silent
ischaemia causing recurrent syncope.
AB - A 57 year old man was admitted for investigation of recurrent syncopal attacks.
Holter monitoring during an attack while in hospital revealed a unique sequence
of gross ST segment elevation, ventricular tachycardia, prolonged ventricular
fibrillation, asystole, junctional and ventricular escape rhythm, and finally
spontaneous restoration of sinus rhythm with severe ST segment depression.
Subsequent coronary arteriography demonstrated severe stenoses of the right
coronary artery, prompting percutaneous transluminal angioplasty and stenting.
The patient has had no further syncopal attacks.
PMID- 9764068
TI - Coronary artery spasm leading to life threatening arrhythmias.
AB - A 39 year old woman sustained life threatening arrhythmias associated with
coronary artery spasm. On both occasions she was attending hospital outpatient
clinics and was successfully resuscitated. Electrocardiography performed during
further episodes of pain suggested that spasm could occur in either the right or
left coronary artery.
PMID- 9764069
TI - Coronary atherosclerosis within a myocardial bridge, not a benign condition.
AB - In patients with myocardial bridging, the area within the bridge usually remains
free from atherosclerotic disease. The case of a 47 year old man is described who
had the rare combination of myocardial bridging with an atherosclerotic plaque
within the area of bridging, which was detected with intravascular ultrasound but
not with coronary angiography. The clinical history of the patient demonstrates
that this is not a benign condition. In symptomatic patients the bridged segment
should be screened for the presence of plaque with intracoronary ultrasound.
PMID- 9764070
TI - Unruptured left ventricular pseudoaneurysm following myocardial infarction.
AB - A 73 year old man developed a left ventricular pseudoaneurysm following acute
myocardial infarction. Coronary angiography showed triple vessel disease with
total occlusion of the right coronary artery. On left ventriculography, a
serpentine-like pseudoaneurysm was demonstrated that originated from the
posterobasal wall of the left ventricle and extended to the right ventricular
free wall. He underwent coronary artery bypass surgery with no plication of the
pseudoaneurysm. An organised thrombus was also found within the cavity of the
pseudoaneurysm. He was doing well approximately eight months after the operation.
The prognosis might be determined by the organised thrombus, the serpentine-like
structure of pseudoaneurysm, the coronary revascularisation, and the vigorous
medical management.
PMID- 9764071
TI - Ruptured ventricular pseudoaneurysm.
PMID- 9764072
TI - Left ventricular pseudoaneurysm in a patient with Dressler's syndrome after
myocardial infarction.
AB - Successful recanalisation of the left anterior descending coronary artery was
performed in a 51 year old man who was admitted two weeks after acute anterior
myocardial infarction. Fourteen days later, the patient developed Dressler's
syndrome with cardiac tamponade, which was immediately punctured. Sternotomy was
performed after two weeks because of progressive haemodynamic deterioration, and
fibrinous masses were removed from the pericardium. The patient recovered but two
weeks later echocardiography showed a perforation of the left ventricular free
wall and formation of a pseudoaneurysm. Intensive monitoring showed significant
enlargement of the pseudoaneurysm, which was subsequently resected. This case
demonstrates that dangerous formation of a pseudoaneurysm can occur not only
during the first days of acute myocardial infarction but also after weeks in
patients suffering from non-infectious pericarditis caused by Dressler's
syndrome. Although the incidence of Dressler's syndrome is declining, patients
should be monitored carefully for several weeks, especially by echocardiography.
PMID- 9764073
TI - Magnetic resonance images of left ventricular pseudoaneurysm.
PMID- 9764074
TI - Coronary stenting for symptomatic myocardial bridging.
PMID- 9764075
TI - The rise and fall of complementary medicine.
PMID- 9764076
TI - Psychological stress and burnout in medical students: a five-year prospective
longitudinal study.
AB - The aim of this study was to assess psychological morbidity and symptoms of
burnout in medical students during their undergraduate training, and to identify
baseline factors that predict psychological morbidity in students in the final
year of the course. It was a 5-year prospective longitudinal cohort study.
Students were assessed in years 1, 4 and 5 of their medical undergraduate
training by means of the GHQ-12 and the Maslach Burnout Inventory. 172 (84.3%),
157 (77.0%) and 155 (75.9%) students out of an original group of 204 completed
assessments in years 1, 4 and 5, respectively. 18 students were above threshold
on the GHQ-12 on all three occasions, 25 on two occasions and 43 on one occasion;
69 students were never a 'case'. Students who were cases on two or more occasions
were more likely to find the medical course stressful during the first year, but
not subsequent years. There was no significant difference between the percentages
of men and women who scored as cases on the GHQ-12 in any of the years. The best
predictor of psychological morbidity in the final year of the course was the GHQ
12 score in year 1. This study suggests that a small group of students repeatedly
experience psychological distress during their medical training.
PMID- 9764077
TI - Electronic fetal heart rate monitoring: retrospective reflections on a twentieth
century technology.
PMID- 9764078
TI - Electroencephalography and video-electroencephalography in the classification of
childhood epilepsy syndromes.
PMID- 9764079
TI - Medical implications of controlled fasting.
PMID- 9764080
TI - Health statistics on the World Wide Web.
PMID- 9764081
TI - Dysmorphophobia by proxy.
PMID- 9764082
TI - Severe rhabdomyolysis after tiger snake bite.
PMID- 9764083
TI - Three cases of pneumomediastinum--after labour, sneezing and compressed-air
diving.
PMID- 9764084
TI - Psychological aspects of eye disorders.
PMID- 9764085
TI - Dwarfism and gigantism in historical picture postcards.
AB - A collection of 893 historical picture postcards from 1900 to 1935, depicting
dwarfs and giants, was analysed from medical and psychosocial viewpoints. In
conditions such as 'bird headed dwarfism', achondroplasia, cretinism, so-called
Aztecs or pinheads, Grebe chondrodysplasia, and acromegalic gigantism, the
disorder could be diagnosed easily. In hypopituitary dwarfism, exact diagnosis
was more difficult because of heterogeneity. The most common conditions depicted
were pituitary dwarfism and achondroplasia. Most of those with gigantism had
pituitary gigantism and acromegaly. Brothers and sisters or parents and their
children provided evidence of mendelian inheritance of some of these disorders.
The cards suggest that being put on show provided, at least in some cases, social
benefits.
PMID- 9764086
TI - The lord and the lady.
PMID- 9764087
TI - The bittersweet demise of Herod the Great.
PMID- 9764088
TI - Eating disorders, nursing and the Allitt report.
PMID- 9764089
TI - Origin of the myth of vampirism.
PMID- 9764090
TI - Perianal Paget's disease.
PMID- 9764091
TI - Myxoedema madness.
PMID- 9764092
TI - Thyroid click.
PMID- 9764093
TI - Early British surgical instruments.
PMID- 9764094
TI - Tutankhamun's paternity.
PMID- 9764095
TI - Male reproductive toxicity of lead in animals and humans. ASCLEPIOS Study Group.
AB - OBJECTIVE: To critically review the literature on male reproductive toxicity of
lead in animals and humans. METHODS: A systematic literature search identified a
total of 32 experimental studies in animals and 22 epidemiological studies, one
case report on humans and five review articles or documents. The studies were
evaluated by paying attention mainly to sample size, study design, exposure, and
dose characterisation, analytical method standardisation, and quality assurance.
RESULTS: Several studies on rats and other rodents indicated that blood lead
concentrations > 30-40 micrograms/dl were associated with impairment of
spermatogenesis and reduced concentrations of androgens. However, other animal
studies, mainly about histopathological, spermatozoal, and hormonal end points,
indicated that certain species and strains were quite resistant to the
reproductive toxicity of lead and that different testicular lead concentrations
could account for these differences. The human studies focused mainly on semen
quality, endocrine function, and birth rates in occupationally exposed subjects,
and showed that exposure to concentrations of inorganic lead > 40 micrograms/dl
in blood impaired male reproductive function by reducing sperm count, volume, and
density, or changing sperm motility and morphology. No relevant effects were
detected on endocrine profile. CONCLUSION: Several factors make it difficult to
extrapolate the animal data to the human situation. The difficulties are mainly
due to differences between species in reproductive end points and to the level of
exposure. Concentrations of blood lead > 40 micrograms/dl seemed to be associated
with a decrease in sperm count, volume, motility, and morphological alterations
and a possible modest effect on endocrine profile. Dose-response relation, in
particular at a threshold level, is poorly understood, and site, mode, or
mechanism of action are unknown. Also, the effects were not always the same or
associated in the same on sperm count and concentration. Some methodological
issues and indications for future studies are discussed.
PMID- 9764096
TI - Development and evaluation of a quality assessment instrument for occupational
physicians.
AB - OBJECTIVES: To develop and apply a method for assessing the quality of the
process of occupational health care for individual patients. METHODS: The
scientific literature was studied to develop a method to assess the quality of
the process of occupational rehabilitation for workers with low back pain. The
method was applied to health care and university workers with low back pain who
were rehabilitated by their occupational physicians. RESULTS: Assessment of
quality of care is regarded as a four step approach. Firstly, guidelines should
be developed and implemented. Secondly, indicators for quality and criteria to
demarcate good and deviant quality were derived from the guidelines. Thirdly, a
method for data collection was chosen. Finally, quality was scored. For
occupational rehabilitation, there was some deviance from the guidelines for most
cases, especially in continuity of care with a deviant rate of 47%. Other
indicators deviated from 1.4%-17.4%. Occupational physicians agreed on the
relevance of the indicators and criteria, but for three indicators they evaluated
the criteria as too rigid. They did not agree with their own performance scores
in 66% of the deviant cases. CONCLUSION: Assessing the quality of the process of
occupational health care with this method is an asset to present methods, but
more specific criteria are needed for a more sensitive assessment.
PMID- 9764097
TI - Quartz exposures and severe silicosis: a role for the hilar nodes.
AB - BACKGROUND: Two stonemasons working together in an environment with high
concentrations of quartz pursued very different clinical courses; one died of
rapidly progressive silicosis and the other developed hilar adenopathy and,
later, early massive fibrosis. The exposures to quartz of these two men were
investigated to allow comment on the pathogenesis of severe silicosis relative to
concentrations of dust. METHODS: Estimates of exposure were based on previously
taken personal dust samples, detailed lifetime occupational histories, and
semiquantitative exposure modelling. RESULTS: One of the men who died had a 30
year exposure estimated to have averaged < 0.1 mg/m3, leading to hilar node
fibrosis and calcification, followed by a five year exposure to about 2 mg/m3
which proved fatal. Estimates of exposure tallied with postmortem measurement of
lung burden, suggesting retention of all dust deposited in the lungs over his
final period of work. The younger man, working from the start of his
apprenticeship alongside the older one, had a six year exposure to about 1.5
mg/m3, which caused hilar node enlargement and subsequent calcification but
minimal lung involvement. CONCLUSIONS: Exposures to relatively low concentrations
of quartz may be capable of causing hilar node fibrosis, impairing the clearance
of any quartz inhaled subsequently. The findings support the concept that
destruction of the hilar nodes by silicotic fibrosis, impairing lung clearance,
has an important pathogenic role in the development of massive fibrosis, and in
men subsequently exposed to very high concentrations of respirable quartz,
rapidly progressive silicosis.
PMID- 9764098
TI - Lung and bladder cancer in a Norwegian municipality with iron and steel producing
industry: population based case-control studies.
AB - OBJECTIVES: To investigate the influence of occupation on the rising incidence of
lung and bladder cancer among men in a Norwegian municipality where an iron and
steel plant constituted the key industry between 1955 and 1989. METHODS: Based on
the lung cancer cases reported to the Cancer Registry of Norway from 1980 to 1992
a population based case-control study was performed, including 86 cases and 196
controls. Information on occupations and smoking habits was collected through
interviews and from the personnel files from the industrial plants. A case
control study on bladder cancer with 52 cases and 156 controls was carried out to
cast light on the role of polycyclic aromatic hydrocarbons (PAHs). RESULTS: An
odds ratio (OR) for lung cancer of 2.9 (95% confidence interval (95% CI) 1.2 to
6.7) was associated with exposure to PAHs. Based on data from personnel files,
increased risk of lung cancer (OR 2.8 95% CI 1.1 to 7.0) was associated with work
experience in the pig iron department at the ironworks. A non-significant OR of
1.8 was associated with exposure to asbestos. Bladder cancer was not associated
with exposure to PAHs at the iron, steel, and coke plant, or with experience from
any of the production departments at the plant. CONCLUSIONS: One fifth of the
lung cancer cases were attributed to exposure to PAHs or asbestos. More than 80%
of the cases of lung cancer were attributed to tobacco smoking. The cancer risk
in the pig iron department may be due to a combination of exposures to PAH,
asbestos, or dust of mixed composition.
PMID- 9764099
TI - Occupational exposures and squamous cell carcinoma of the oral cavity, pharynx,
larynx, and oesophagus: a case-control study in Sweden.
AB - OBJECTIVES: This community based case-referent study was initiated to investigate
aetiological factors for squamous cell carcinoma of the upper gastrointestinal
tract. METHODS: The study was based on all Swedish men aged 40-79 living in two
regions of Sweden during 1988-90. Within that base, efforts were made to identify
all incident cases of squamous cell carcinoma of the oral cavity, oropharynx and
hypopharynx, larynx, and oesophagus. Referents were selected as a stratified
(age, region) random sample of the base. The response was 90% among cases and 85%
among referents. There were 545 cases and 641 referents in the final study group.
The study subjects were interviewed about several lifestyle factors and a life
history of occupations and work tasks. The exposure to 17 specific agents were
coded by an occupational hygienist. The relative risk (RR) of cancer was
calculated by logistic regression, standardising for age, geographical region,
and alcohol and tobacco consumption. RESULTS: Exposure to asbestos was associated
with an increased risk of laryngeal cancer, and a dose-response relation was
present. The RR was 1.8 (95% confidence interval (95% CI) 1.1 to 3.0) in the
highest exposure group. More than eight years of exposure to welding fumes was
associated with an increased risk of pharyngeal cancer (RR 2.3 (1.1 to 4.7)), and
laryngeal cancer (RR 2.0 (1.0 to 3.7)). There were indications of a dose-response
for duration of exposure. Associations were also found for high exposure to
polycyclic aromatic hydrocarbons (PAHs) and oesophageal cancer, RR 1.9 (1.1 to
3.2). Exposure to wood dust was associated with a decreased risk of cancer at the
studied sites. CONCLUSIONS: Some of the present findings confirm known or
suspected associations--such as asbestos and laryngeal cancer. The study
indicates that welding may cause an increased risk of pharyngeal as well as
laryngeal cancer. The findings corroborate an association between exposure to
PAHs and oesophageal cancer.
PMID- 9764100
TI - Preventive measures reduce exposure to polycyclic aromatic hydrocarbons at a
graphite electrode plant.
AB - OBJECTIVE: This study assessed the efficacy of preventive measures in a graphite
electrode plant aimed at reducing occupational exposure to polycyclic aromatic
hydrocarbons (PAHs). METHODS: Electrode workers (n = 146) answered a
questionnaire and provided an end of shift urine sample. Urinary 1-hydroxypyrene
(1-hpur), a biological marker of exposure to PAHs, was measured by high
performance liquid chromatography coupled with: (a) fluorescence detection. 1
Hydroxypyrene concentrations were compared with the concentrations measured
before implementing the preventive measures; and (b) those of a control group of
54 men not occupationally exposed to PAHs. RESULTS: After implementation of
preventive measures, median concentrations 1-hpur were significantly reduced in
some groups of workers: by -24%, -37% and -30% in workers at the green electrode
unit, one baking impregnation unit, and the laboratory, respectively. In workers
at a second baking impregnation unit, in end product finishing and in the power
station 1-hpur concentrations were unchanged. Urinary 1-hp concentrations were
still significantly higher in each group of workers than in the control group (p
< 0.001 for any comparison). Concentrations in the workers varied with the type
of job, the highest values being found in workers engaged in the power station,
in the two baking impregnation units and in the green electrode unit.
CONCLUSIONS: Implementing preventive measures significantly reduced exposure to
PAHs at a graphite electrode plant. The reduction in median and peak
concentrations of 1-hpur, which reflects total exposure to, and internal dose of
PAHs, was most evident in workers employed in the units where preventive measures
had been taken. Despite an overall reduction, further preventive measures are
needed to minimise exposure to PAHs and consequently the risk of adverse health
effects.
PMID- 9764101
TI - Work stress and recovery measured by urinary catecholamines and cortisol
excretion in long distance coach drivers.
AB - OBJECTIVES: To evaluate coach drivers' work stress during work and in the course
of recovery from work by measurement of urinary catecholamines and cortisol.
METHODS: The urinary excretion rate of adrenaline, noradrenaline, and cortisol of
10 coach drivers was studied during a long distance trip of three days and two
consecutive days off. Each driver was asked to provide seven urine samples on the
working days and six urine samples on the days off. The second day off was
considered as the baseline. RESULTS: An occupationally induced disturbance of the
circadian rhythmicity was found for adrenaline and noradrenaline but not for
cortisol. The mean excretion rates of adrenaline on the first working day and
most samples on all working days were higher than the baseline. For both
adrenaline and noradrenaline the mean excretion rates on the first day off were
lower than the baseline. For cortisol, the mean excretion rate on all working
days was higher than the baseline. A trend towards accumulation of cortisol
excretion from the first working day to the third working day was found. A
backward shift in peak concentrations was found for adrenaline and noradrenaline
on the second working day, as was a forward shift in peak concentration of
cortisol on both days off. CONCLUSIONS: Long distance coach drivers showed
occupationally induced reactivity in rates of urinary excretion of adrenaline,
noradrenaline, and cortisol. After the outward journey the rates of excretion of
catecholamines did not return to baseline values. The course of recovery in
adrenaline excretion after the journey showed a new phenomenon, which has been
called "fatigue debt". It is recommended that longer resting times in shuttle bus
trips and fixed days off after these kind of trips should be planned. Extensive
future research should be focused on the additional relations between fatigue
debt and health complaints.
PMID- 9764102
TI - Ergonomic stressors and upper extremity disorders in vehicle manufacturing: cross
sectional exposure-response trends.
AB - OBJECTIVE: To evaluate the association between upper extremity soft tissue
disorders and exposure to preventable ergonomic stressors in vehicle
manufacturing operations. METHODS: A cross sectional study was conducted in one
vehicle stamping plant and one engine assembly plant. A standardised physical
examination of the upper extremities was performed on all subjects. An
interviewer administered questionnaire obtained data on demographics, work
history, musculoskeletal symptoms, non-occupational covariates, and psycho
physical (relative intensity) ratings of ergonomic stressors. The primary
exposure score was computed by summing the responses to the psychophysical
exposure items. Multivariate regression analysis was used to model the prevalence
of disorders of the shoulders or upper arms, wrists or hands, and all upper
extremity regions (each defined both by symptoms and by physical examination plus
symptoms) as a function of exposure quartile. RESULTS: A total of 1315 workers
(85% of the target population) was examined. The prevalence of symptom disorders
was 22% for the wrists or hands and 15% for the shoulders or upper arms; cases
defined on the basis of a physical examination were about 80% as frequent.
Disorders of the upper extremities, shoulders, and wrists or hands all increased
markedly with exposure score, after adjustment for plant, acute injury, sex, body
mass index, systemic disease, and seniority. CONCLUSIONS: Musculoskeletal
disorders of the upper extremities were strongly associated with exposure to
combined ergonomic stressors. The exposure-response trend was very similar for
symptom cases and for physical examination cases. It is important to evaluate all
dimensions of ergonomic exposure in epidemiological studies, as exposures often
occur in combination in actual workplaces.
PMID- 9764103
TI - Prevalence of work related musculoskeletal disorders in active union carpenters.
AB - OBJECTIVES: To determine the prevalence and risk factors for work related
musculoskeletal disorders among union carpenters. METHODS: A detailed
questionnaire on musculoskeletal symptoms and work history was administered to
522 carpenters. The symptom questions assessed if carpenters experienced pain,
numbness, or tingling in a particular body region. A subset of this group then
received a physical examination of the upper extremities and knees. RESULTS: The
study group was primarily white (94.9%) and male (97.8%) with a mean age of 42.3
years. The highest prevalence of work related musculoskeletal disorders cases by
carpentry specialty ranged from 20%-24% for those doing drywall or ceiling,
finishing or framing, and the building of concrete forms. Generally, as duration
of employment increased, the prevalence of symptoms increased. An adjusted
logistic regression analysis showed that the group with the longest (> or = 20
years) duration of employment in carpentry was significantly associated with work
related musculoskeletal disorders of the shoulders (odds ratio (OR) 3.2, 95%
confidence interval (95% CI) 1.1 to 8.9), hands or wrists (OR 3.1, 95% CI 1.1 to
8.4), and knees (OR 3.5, 95% CI 1.3 to 9.2). Also, analyses showed that
carpenters who reported that they had little or no influence over their work
schedule had significant increases of work related musculoskeletal disorders of
the shoulders, hips, and knees with ORs of 1.9 (95% CI 1.1 to 3.2), 2.9 (95% CI
1.1 to 7.2), and 2.3 (95% CI 1.2 to 4.1), respectively. Feeling exhausted at the
end of day was also a significant risk factor for work related musculoskeletal
disorders of the knee (OR 1.8, 95% CI 1.1 to 3.1). Upper extremity disorders were
the most prevalent work related musculoskeletal disorders reported among all
carpenters. Drywall or ceiling activities involve a considerable amount of
repetitive motion and awkward postures often with arms raised holding heavy dry
walls in place, whereas form work is notable for extensive lumbar flexion and had
the two highest rates of work related musculoskeletal disorders. The psychosocial
element of job control was associated with both upper and lower extremity
disorders. These union carpenters, who were relatively young, already were
experiencing considerable work related physical problems. CONCLUSION: This study
supports the need for vigilant ergonomic intervention at job sites and early
ergonomic education as an integral part of apprenticeship school training to
ensure that carpenters remain fit and healthy throughout their working lifetime.
PMID- 9764104
TI - Indoor nitrogen dioxide in homes along trunk roads with heavy traffic.
AB - OBJECTIVES: To assess the distribution of indoor nitrogen dioxide (NO2)
concentrations in homes located in differing environments, and to investigate the
influence of factors such as automobile exhaust on the indoor environment.
METHODS: The concentrations of indoor NO2 over 24 hours were measured in both the
heating and non-heating periods in homes of pupils from nine elementary schools
in Chiba, Japan. Information on factors that could influence indoor environments
was collected by questionnaire. RESULTS: Indoor NO2 concentrations during the
heating period were higher in homes with unvented heaters than in homes with
vented heaters, although the concentrations varied greatly among homes primarily
because of the type of heating device used. During the non-heating period, indoor
NO2 concentrations were significantly higher in homes adjacent to trunk roads
than in homes located in other areas. Multiple regression analysis showed that
indoor NO2 concentrations were associated with atmospheric NO2 in homes with
vented heaters during the heating period, and in homes in areas other than on the
roadside during the non-heating period. In areas other than the roadside,
cigarette smoking in indoor environments also significantly contributed to indoor
NO2. The average concentrations of indoor NO2 in the homes of pupils attending
each school were significantly related to the atmospheric NO2 in areas other than
the roadside. However, the relation between indoor and atmospheric NO2
concentrations was not significant in roadside areas. CONCLUSIONS: These findings
suggest that indoor NO2 concentrations are related to the atmospheric NO2 and
type of heating appliances, and are also affected by automobile exhaust in homes
located in roadside areas.
PMID- 9764105
TI - Occupational asthma due to porcine pancreatic amylase.
PMID- 9764106
TI - Assessment of mechanical exposure in ergonomic epidemiology.
AB - In recent years several different methods have been developed to assess
mechanical exposures, which are related to musculoskeletal disorders in ergonomic
epidemiology. Each of these methods is capable of measuring one or more aspects
of risk factors, but has drawbacks as well. Improper application of methods might
result in biased exposure estimates, which has serious consequences for risk
estimates arising from epidemiological studies. The aim of this paper was to
systematically evaluate the usefulness of different measurement methods in terms
of accuracy and applicability. Assessment of external exposure measures by
subjective judgements (from experts or self reports from workers), observational
methods (on site or afterwards from video recordings), and direct measurements
methods (at work or during laboratory simulations) are discussed for each of the
dimensions of exposure level, duration, and frequency. It is concluded that
expert judgements and self reports give only limited insight into the occurrence
of tasks and activities. Further information can be obtained from observations,
which can best be combined with direct measurements of exposure to posture,
movement, and exerted forces to achieve exposure profiles by occupational task.
Internal exposures estimated by biomechanical modelling mostly consider the low
back and require information on postures of the different body segments and
exerted forces, completed with movement data in the case of dynamic models.
Moreover, electromyography (EMG) and measurements of intra-abdominal pressure
might be used for this purpose. Both biomechanical models and EMG are useful
methods to assess internal exposure, but biomechanical models should not be
restricted to the level of compressive forces on the lower back. Finally, current
problems and future directions in measurement strategies and methods are
discussed.
PMID- 9764108
TI - Comprehensive evaluation of long-term trends in occupational exposure: Part 2.
Predictive models for declining exposures.
AB - OBJECTIVES: To explore the effects of various factors related to the industry,
the contaminant, and the period and type of sampling on long term declining
trends in occupational exposure. METHODS: Linear regression analyses were used to
assess the relation between reductions in exposure and geographical location,
industrial sector, type of contaminant, type of monitoring, carcinogenic
classification, calendar period, duration of sampling, and number of reductions
in the threshold limit value during the sampling period. Both univariable and
multivariable models were applied. RESULTS: Based on univariable analyses, the
findings suggest that exposures declined more rapidly in manufacturing than in
mining, more rapidly for aerosol contaminants than for vapours, and more rapidly
when biological, rather than airborne, monitoring was conducted. Exposures
collected more recently (first year of sampling in 1972 or later) fell more
rapidly than exposures first evaluated during earlier periods. Irrespective of
when the data were collected, the results also suggest that the longer the
duration of sampling the slower the rate of decline. Taken together, we found
that characteristics related to the contaminant, the industry, the sampling
period, and the type of sampling explained a substantial proportion of the
variability for exposures evaluated before 1972 (R2 = 0.78) and for sites
evaluated both before and after 1972 (R2 = 0.91), but explained essentially no
variation for data gathered exclusively after 1972 (R2 = 0.04). CONCLUSIONS: By
identifying factors that have affected the rates of reduction in a consistent
fashion, the results should guide investigators in estimating historical levels
when studies assessing exposure-response relations are carried out.
PMID- 9764107
TI - Comprehensive evaluation of long-term trends in occupational exposure: Part 1.
Description of the database.
AB - OBJECTIVES: To conduct a comprehensive evaluation of long term changes in
occupational exposure among a broad cross section of industries worldwide.
METHODS: A review of the scientific literature identified studies that reported
historical changes in exposure. About 700 sets of data from 119 published and
several unpublished sources were compiled. Data were published over a 30 year
period in 25 journals that spanned a range of disciplines. For each data set, the
average exposure level was compiled for each period and details on the
contaminant, the industry and location, changes in the threshold limit value
(TLV), as well as the type of sampling method were recorded. Spearman rank
correlation coefficients were used to identify monotonic changes in exposure over
time and simple linear regression analyses were used to characterise trends in
exposure. RESULTS: About 78% of the natural log transformed data showed linear
trends towards lower exposure levels whereas 22% indicated increasing trends.
(The Spearman rank correlation analyses produced a similar breakdown between
exposures monotonically increasing or decreasing over time.) Although the rates
of reduction for the data showing downward trends ranged from -1% to -62% per
year, most exposures declined at rates between -4% and -14% per year (the
interquartile range), with a median value of -8% per year. Exposures seemed to
increase at rates that were slightly lower than those of exposures which have
declined over time. Data sets that showed downward (versus upward) trends were
influenced by several factors including type and carcinogenicity of the
contaminant, type of monitoring, historical changes in the threshold limit values
(TLVs), and period of sampling. CONCLUSIONS: This review supports the notion that
occupational exposures are generally lower today than they were years or decades
ago. However, such trends seem to have been affected by factors related to the
contaminant, as well as to the period and type of sampling.
PMID- 9764109
TI - Workplace risk factors for cancer in the German rubber industry: Part 1.
Mortality from respiratory cancers.
AB - OBJECTIVES: To determine the cancer specific mortality by work area among active
and retired male workers in the German rubber industry. METHODS: A cohort of
11,663 male German workers was followed up for mortality from 1 January 1981 to
31 December 1991. Cohort members were classified as active (n = 7536) or retired
(n = 4127) as of 1 January 1981 and had been employed for at least one year in
one of five study plants producing tyres or technical rubber goods. Work
histories were reconstructed with routinely documented "cost centre codes" which
were classified into six categories: I preparation of materials; II production of
technical rubber goods; III production of tyres; IV storage and dispatch; V
maintenance; and VI others. Standardised mortality ratios (SMRs) adjusted for age
and calendar year and 95% confidence intervals (95% CIs), stratified by work area
(employment in respective work area for at least one year) and time related
variables (year of hire, lagged years of employment in work area), were
calculated from national reference rates. RESULTS: SMRs for laryngeal cancer were
highest in work area I (SMR 253; 95% CI 93 to 551) and were significant among
workers who were employed for > 10 years in this work area (SMR 330; 95% CI 107
to 779). Increased mortality rates from lung cancer were identified in work areas
I (SMR 162; 95% CI 129 to 202), II (SMR 134; 95% CI 109 to 163), and V (SMR 131;
95% CI 102 to 167). Mortality from pleural cancer was increased in all six work
areas, and significant excesses were found in work areas I (SMR 448; 95% CI 122
to 1146), II (SMR 505; 95% CI 202 to 1040), and V (SMR 554; 95% CI 179 to 1290).
CONCLUSION: A causal relation between the excess of pleural cancer and exposure
to asbestos among rubber workers is plausible and likely. In this study, the
pattern of excess of lung cancer parallels the pattern of excess of pleural
cancer. This points to asbestos as one risk factor for the excess deaths from
lung cancer among rubber workers. The study provides further evidence for an
increased mortality from laryngeal cancer among workers in the rubber industry,
particularly in work area I.
PMID- 9764110
TI - Workplace risk factors for cancer in the German rubber industry: Part 2.
Mortality from non-respiratory cancers.
AB - OBJECTIVES: To determine the mortality from non-respiratory cancers by work area
among active and retired male workers of the German rubber industry. METHODS: A
cohort of 11,633 male German workers was followed up for mortality from 1 January
1981 to 31 December 1991. Cohort members were active (n = 7536) or retired (n =
4127) on 1 January 1981 and had been employed for at least one year in one of
five study plants producing tyres or technical rubber goods. Work histories were
reconstructed from routinely documented "cost centre codes" and classified into
six categories: I preparation of materials; II production of technical rubber
goods; III production of tyres; IV storage and dispatch; V general service; VI
others. Standardised mortality ratios (SMRs) and 95% confidence intervals (95%
CIs), controlling for age and calendar year and stratified by work area
(employment in respective work area for at least one year) and time related
variables (year of hire, lagged years of employment in work area) were calculated
from national mortality rates as the reference. RESULTS: Significant increases in
mortality were found for pharyngeal cancer in work area IV (three deaths, SMR
486, 95% CI 101 to 1419), oesophageal cancer in work area III (11 deaths, SMR
227, 95% CI 114 to 407), and leukaemia in work areas I (11 deaths, SMR 216; 95%
CI 108 to 387) and II (14 deaths, SMR 187; 95% CI 102 to 213). Furthermore,
increased SMRs were found for stomach cancer in work area I (22 deaths, SMR 134;
95% CI 84 to 203), colon cancer in work area II (27 deaths, SMR 131, 95% CI 86 to
191), prostatic cancer in work area V (27 deaths, SMR 152, 95% CI 99 to 221), and
bladder cancer in work areas IV (six deaths, SMR 253; 95% CI 93 to 551) and V (12
deaths, SMR 159, 95% CI 82 to 279). Mortality from cancer of the liver or gall
bladder, pancreas and kidney, and from lymphomas was not substantially increased
in any of the work areas. CONCLUSIONS: Mortality from cancer of several sites was
associated with specific work areas. Some of these associations have been
reported previously. Future analyses of our study will have to determine the role
of specific exposures in the aetiology of these cancers.
PMID- 9764111
TI - Residential wire codes: reproducibility and relation with measured magnetic
fields.
AB - OBJECTIVES: To investigate the reproducibility of wire codes to characterise
residential power line configurations and to determine the extent to which wire
codes provide a proxy measure of residential magnetic field strength in a case
control study of childhood leukaemia conducted in nine states within the United
States. METHODS: Misclassification of wire codes was assessed with independent
measurements by two technicians for 187 residences. The association between
categories of wire code and measured level of magnetic field was evaluated in 858
residences with both a wire code measurement and a 24 hour measurement of the
magnetic field in the bedroom. The strength of the association between category
of wire code and risk of leukaemia was examined in two regions with different
average levels of magnetic field in homes with high categories of wire code.
RESULTS: The reproducibility of any of three different classifications of wire
codes was excellent (kappa > or = 0.89). Mean and median magnetic fields, and the
percentage of homes with high magnetic fields increased with increasing category
for each of the wire code classification schemes. The size of the odds ratios for
risk of leukaemia and high categories of wire code did not reflect the mean
levels of the magnetic field in those categories in two study regions.
CONCLUSION: Misclassification of categories of wire code is not a major source of
bias in the study. Wire codes provide a proxy measure of exposure to residential
magnetic fields. If magnetic fields were a risk factor for leukaemia, however,
there would be some attenuation of risk estimates based on wire codes because of
misclassification of exposure to magnetic fields at both extremes of the wire
code range. The lack of an association between high categories of wire code and
risk of leukaemia cannot be explained by a failure of the wire code
classification schemes to estimate exposure to magnetic fields in the study area.
PMID- 9764112
TI - Evaluating the effectiveness of gloves in reducing the hazards of hand
transmitted vibration.
AB - OBJECTIVES: A method of evaluating the effectiveness of gloves in reducing the
hazards of hand-transmitted vibration is proposed. METHOD: The glove isolation
effectiveness was calculated from: (a) the measured transmissibility of a glove,
(b) the vibration spectrum on the handle of a specific tool (or class of tools),
and (c) the frequency weighting indicating the degree to which different
frequencies of vibration cause injury. With previously reported tool vibration
spectra and glove transmissibilities (from 10-1000 Hz), the method was used to
test 10 gloves with 20 different powered tools. RESULTS: The frequency weighting
for hand-transmitted vibration advocated in British standard 6842 (1987) and
international standard 5349 (1986) greatly influences the apparent isolation
effectiveness of gloves. With the frequency weighting, the gloves had little
effect on the transmission of vibration to the hand from most of the tools. Only
for two or three tools (those dominated by high frequency vibration) did any
glove provide useful attenuation. Without the frequency weighting, some gloves
showed useful attenuation of the vibration on most powered tools. CONCLUSIONS: In
view of the uncertain effect of the vibration frequency in the causation of
disorders from hand-transmitted vibration, it is provisionally suggested that the
wearing of a glove by the user of a particular vibratory tool could be encouraged
if the glove reduces the transmission of vibration when it is evaluated without
the frequency weighting and does not increase the vibration when it is evaluated
with the frequency weighting. A current international standard for the
measurement and evaluation of the vibration transmitted by gloves can classify a
glove as an antivibration glove when it provides no useful attenuation of
vibration, whereas a glove providing useful attenuation of vibration on a
specific tool can fail the test.
PMID- 9764113
TI - Decline in lung function related to exposure and selection processes among
workers in the grain processing and animal feed industry.
AB - OBJECTIVES: To follow up workers in the grain processing and animal feed industry
five years after an initial survey, and to monitor exposures to organic dust and
endotoxin and changes in prevalence of respiratory symptoms and lung function.
METHODS: Outcome measures in the present survey were decline in lung function
over five years, rapid annual decline in forced expiratory volume in one second
(FEV1) above 90 ml.s-1, and loss to follow up. RESULTS: Among 140 workers
included in the longitudinal analysis, annual decline in FEV1 and maximal mid
expiratory flow (MMEF) were significantly related to occupational exposure to
dust and endotoxin in the grain processing and animal feed industry. Assuming a
cumulative exposure over a working life of 40 years with an exposure of 5 mg.m-3,
the estimated effect on the FEV1 would be a decline of 157 ml.s-1 (95% CI 13 to
300)--that is, about 4% of the group mean FEV1 and 473 ml.s-1 (95% CI 127 to 800)
of the MMEF (about 12%). Workers with a dust exposure > 4 mg.m-3 or endotoxin
concentrations > 20 ng.m-3 at the 1986-8 survey had significantly higher risk of
rapid decline in FEV1 (odds ratio (OR) 3.3, 95% CI 1.02 to 10.3). The relations
between occupational exposure and decline in lung function in this study
occurred, despite the selection through the healthy worker effect that occurred
as well. Increasing working years was related to decreasing annual decline in
FEV1 and fewer people with rapid decline in FEV1 (OR 0.04, 95% CI 0 to 0.61 for
over 20 v < 5 working years in the grain processing and animal feed industry).
The presence of respiratory symptoms at baseline was a strong predictor of
subsequent loss to follow up. Baseline lung function was not found to be
predictive of subsequent loss to follow up. However, among workers lost to follow
up the number of working years was more strongly negatively related to baseline
lung function than among the workers who were studied longitudinally.
CONCLUSIONS: The existence of the healthy worker effect implies that an exposure
response relation in the grain processing and animal feed industry may well be
underestimated. This should be taken into account when health based recommended
limit values are to be developed.
PMID- 9764114
TI - Changes in airway function and bronchial responsiveness after acute occupational
exposure to chlorine leading to treatment in a first aid unit.
AB - OBJECTIVES: To describe the baseline characteristics and the time course of
changes in lung function in workers accidentally inhaling high concentrations of
chlorine in a prospective study. METHODS: Baseline spirometry and methacholine
challenge test were performed in a cohort of 278 workers at risk of accidental
inhalation of chlorine. Workers in whom accidental inhalation led to intervention
in a first aid unit were reassessed five to 25 days after the accident and
serially thereafter when there where notable changes. RESULTS: During a four year
follow up period, 13 workers were seen at the first aid unit after a symptomatic
accidental inhalation. Three of them experienced notable functional changes: one
worker experienced a 10% fall in forced expiratory volume in one second (FEV1),
and the other two had a notable fall in the concentration of methacholine that
caused a 20% fall in FEV1 (PC20). Two workers were smokers and one had a personal
history of atopy. Baseline assessment was within the normal range in these three
workers. Recovery was complete three months after the accidental inhalation.
CONCLUSION: Transient but notable decreases in airway function or increases in
bronchial responsiveness can occur after an accidental inhalation of high
concentrations of chlorine in workers at risk.
PMID- 9764115
TI - Acute myeloid and monocytic leukaemia and benzene exposure in petroleum
distribution workers in the United Kingdom.
PMID- 9764117
TI - Dynamite plunger plots should not be used.
PMID- 9764116
TI - Occupational asthma due to amylase.
PMID- 9764118
TI - Preventive strategies in early psychosis: verging on reality.
PMID- 9764119
TI - Early detection and intervention of schizophrenia: rationale and research.
AB - BACKGROUND: The primary rationale for early detection and intervention in
schizophrenia is the disorder's severity, chronicity and treatment resistance.
This suggests that researchers pay closer attention to schizophrenia's premorbid
and onset phases, when the vulnerability to psychosis becomes expressed and the
neurobiological deficit processes driving symptom formation appear to be the most
active. METHOD: We review the evidence that brain plasticity may be retained or
reversed despite deficit processes. RESULTS: The data are preliminary but
suggestive enough to warrant further research. CONCLUSIONS: Overall, we need to
focus on the early course of schizophrenia, detecting cases early at onset or in
the prodrome, testing whether this enhances treatment response and prognosis, and
predicting at-risk cases early in the prodromal phase. Designs to address these
questions are presented, and relevant issues are discussed.
PMID- 9764120
TI - School teacher ratings predictive of psychiatric outcome 25 years later.
AB - BACKGROUND: The current study examines teacher ratings as a tool for identifying
students at risk of developing psychosis. Follow-up and follow-back studies have
shown that teachers are capable of identifying individuals who later develop
serious mental illness. METHOD: We examine the long-term outcomes for individuals
at genetic risk who were identified as showing markedly deviant behaviour and
those identified who did not show markedly deviant behaviour. RESULTS: Teachers
were able to correctly anticipate 35% of students who developed schizophrenia.
Furthermore, those identified as showing markedly deviant behaviour had poorer
clinical and psychiatric outcomes 10 and 25 years later than those identified as
not behaving with marked deviance. Their ratings also differentiated, within the
group of people with schizophrenia, which individuals would show evidence of
poorer functioning 25 years later. These results were replicated in a group of
students not at genetic risk of schizophrenia. Within this low-risk group,
teachers were able to predict which students would develop psychotic disorders.
CONCLUSIONS: Teacher ratings were particularly useful in predicting clinical and
psychiatric outcomes 10 and 25 years later. The applicability of these findings
in early intervention and treatment research is discussed.
PMID- 9764121
TI - Prediction of psychosis. A step towards indicated prevention of schizophrenia.
AB - BACKGROUND: The identification of people at high risk of becoming psychotic
within the near future creates opportunities for early intervention prior to the
onset of psychosis to prevent or minimise later ill-health. The present study
combines current knowledge about risk factors for schizophrenia with our
knowledge of psychotic prodromes in an attempt to identify a group particularly
vulnerable to impending psychosis. We wanted to identify people with high
likelihood of transition to psychosis within a follow-up period of 12 months, and
to determine the rate of transition to psychosis in this group. METHOD: Various
state and trait risk factors for psychosis were used alone and in combination to
operationally define a putatively high-risk group. Operationalised criteria for
onset of psychosis were established. The individuals were assessed monthly on
measures of psychopathology for six months. RESULTS: Eight out of 20 people made
the transition to frank psychosis within a six-month follow-up period. Follow-up
of this group is still in progress, and the 12 month transition rate might prove
to be higher still. CONCLUSIONS: We have demonstrated that it is possible to
identify individuals with a high likelihood of onset of psychosis within a brief
follow-up period. This lays the foundation for early treatment in an attempt to
prevent, delay or minimise the severity of first onset of schizophrenia.
PMID- 9764122
TI - Understanding the topography of the early psychosis pathways. An opportunity to
reduce delays in treatment.
AB - BACKGROUND: This study aims to gain an understanding of treatment delays and
their nature in initial psychotic episodes. We investigated to whom people turn
for help, how long that approach takes and subsequent delays in commencing
treatment. METHOD: Qualitative and quantitative methods were combined with
interviews of 62 people suffering from first-episode psychoses, aged 16-30 years,
who had recently accessed a specialist mental health service in Melbourne,
Australia. A modified version of the World Health Organization Encounter Form was
analysed in conjunction with other data. RESULTS: Pathways to care and the ways
in which they were experienced were highly variable, with 50% of people
experiencing psychotic symptoms before approaching any service. The general
practitioner played a key role with 50% of people having had GP contact at some
point prior to commencing effective treatment. Where an individual's own efforts
to seek early help failed, the role of relatives and others was subsequently
vital. CONCLUSIONS: Opportunities exist for shortening delays through targeted
health promotion activities and professional training. The need is indicated for
a multi-layered or topographical strategy to identify and minimise critical
barriers on the route to early intervention. Refinement of interview techniques
and instruments of measurement are needed to enhance the explanatory power of
data collected.
PMID- 9764123
TI - Hillside study of risk and early detection in schizophrenia.
AB - BACKGROUND: The Hillside Study of Risk and Early Detection in Schizophrenia is a
prospective study of young probands (ages 14-28) and their at-risk siblings (ages
14-24). A major goal is the identification of early predictors of illness that
will facilitate intervention. The project design and pilot study are discussed.
METHOD: Fifteen adolescents were compared to 14 typical age-of-onset adults, all
undergoing their first hospitalisation for schizophrenia. RESULTS: There were no
differences between adolescents and adults on any of the measures administered
(i.e. attention, eye tracking, neurocognitive or clinical). In addition, for the
sample overall, no association was found between neurocognitive functions and
clinical state, either at admission or after treatment. CONCLUSIONS: Individuals
with adolescent onset of schizophrenia are considered to be representative of
schizophrenia in general. Furthermore, neurocognitive deficits and clinical
symptoms are concluded to be two independent classes of risk indicators.
PMID- 9764124
TI - Early intervention for schizophrenic disorders. Implementing optimal treatment
strategies in routine clinical services. OTP Collaborative Group.
AB - BACKGROUND: Early detection and intervention in schizophrenic disorders is an
important challenge for psychiatry. METHOD: Review of literature on effective
biomedical and psychosocial intervention strategies. RESULTS: Comprehensive
programmes of drug and psychosocial interventions with adults who show early
signs and symptoms of schizophrenic disorders may contribute to a lower incidence
and prevalence of major episodes of schizophrenia. These programmes combine early
detection of psychotic features by primary care services, with close liaison with
mental health professionals. Long-term monitoring of signs of recurrence, with
further intervention, appears essential to maintain these benefits. CONCLUSIONS:
Field trials demonstrate that effective early treatment strategies can be
routinely applied in clinical practice.
PMID- 9764125
TI - Home-oriented management programme for people with early psychosis.
AB - BACKGROUND: The HOMES (Home-Oriented Management of Early Psychosis) programme is
a new home-based management programme for people presenting for the first time
with psychotic illnesses. The present paper aims to present preliminary data as
to the efficacy of this programme and factors identified as being associated with
successful prevention of hospital admission. METHOD: The programme applied to all
the people presenting to the Dandenong Hospital Department of Psychiatry with
first-episode psychosis who are considered suitable at first assessment for home
based management. A programme description is included in the paper. Prospective
evaluation data on the first 31 people managed within the programme is presented.
RESULTS: Twenty-two out of 31 people were managed without the necessity for
hospital admission. Illness severity was not related to the ability to manage
this group of people outside of hospital. The level of social support and
duration of untreated psychosis prior to treatment, may be most closely related
to home-based treatment success. CONCLUSIONS: Home-based management of people
with first-episode psychosis is feasible and offers a viable alternative to
admission for this group. Home-based treatment is dependent on the degree of
social support but is independent of the degree of illness severity.
PMID- 9764126
TI - First-episode schizophrenia with long duration of untreated psychosis. Pathways
to care.
AB - BACKGROUND: The early course of illness in first-episode schizophrenia was
examined with special emphasis on the duration of untreated psychosis and
pathways to care. METHOD: The consecutively admitted individuals (n = 34) were
assessed on premorbid functioning, duration of untreated psychosis, global
functioning, symptoms and social network. To clarify the obstacles for receiving
earlier treatment, 17 case histories with long duration of untreated psychosis
were intensively studied. RESULTS: The duration of untreated psychosis was on
average very long (130 weeks), the median value was 54 weeks. The long duration
of untreated psychosis group (> 54 weeks) had greater deterioration in the
premorbid phase, a weaker social network and were more withdrawn than the short
duration of untreated psychosis group (< 54 weeks). The main obstacles for
receiving treatment were withdrawal and poor social network. CONCLUSIONS: In
order to identify people earlier, a system of detection must be mobile, easily
accessible and attentive to early symptoms of psychosis. It seems to be important
to educate the social network related to the individual about the importance of
early treatment.
PMID- 9764127
TI - Early intervention in psychosis. The critical period hypothesis.
AB - BACKGROUND: We consider the evidence for the proposition that the early phase of
psychosis (including the period of untreated psychosis) is a critical period in
which (a) long-term outcome is predictable, and (b) biological, psychological and
psychosocial influences are developing and show maximum plasticity. METHOD: First
episode prospective studies, predictors of outcome and the genesis of patients'
key appraisals of their psychosis are reviewed. RESULTS: The data support the
notion of the 'plateau effect', first coined by Tom McGlashan, which suggested
that where deterioration occurs, it does so aggressively in the first 2-3 years;
and that critical psychosocial influences, including family and psychological
reactions to psychosis and psychiatric services, develop during this period.
CONCLUSIONS: The early phase of psychosis presents important opportunities for
secondary prevention. We outline a prototype of intervention appropriate to the
critical period. The data challenge the widely held assumption that first-episode
psychosis is a benign illness posing little risk.
PMID- 9764128
TI - Research and treatment strategies in first-episode psychoses. The Pittsburgh
experience.
AB - BACKGROUND: Studies of first-episode patients allow investigation of the
biological basis of psychotic disorders without the potential confounds of prior
treatment and illness chronicity. Prospective studies of this population can
clarify the impact of illness course and treatment on neurobiology. METHOD: We
summarise preliminary findings from our ongoing magnetic resonance imaging and
spectroscopy studies of first-episode schizophrenia patients being conducted
prospectively from index evaluations through a period of two years; during this
period, patients were treated with either a conventional antipsychotic such as
haloperidol, or the atypical risperidone. RESULTS: Baseline neurobiological
evaluations in first-episode schizophrenia patients have revealed evidence for
structural and functional brain abnormalities consistent with a
neurodevelopmental model of this illness. Our preliminary data support the value
of risperidone as an antipsychotic drug of first choice among patients with early
schizophrenic illness. CONCLUSIONS: Focused studies of first-episode patients
have the potential to unravel pathophysiology of schizophrenic illness. Such
knowledge is critical for more effective early detection, intervention and even
prevention of this enigmatic disorder.
PMID- 9764129
TI - Pharmacotherapy of first-episode schizophrenia.
AB - BACKGROUND: A growing interest in first-episode schizophrenia reflects the belief
that this line of investigation will lead to further developments regarding
schizophrenia's aetiology, course and outcome. METHOD: Evidence from more recent
clinical trials involving first-episode schizophrenia is integrated with
neuroimaging data, specifically positron emission tomography, to provide
direction regarding pharmacotherapy. RESULTS: Individuals with a first episode of
schizophrenia appear particularly responsive to pharmacotherapy, as well as quite
sensitive to side-effects. At the same time, current clinical and receptor
binding data support the efficacy of low-dose neuroleptic treatment. CONCLUSIONS:
Early and effective treatment of schizophrenia has been associated with better
long-term outcome. Low-dose neuroleptic therapy is an effective treatment
strategy and the diminished risk of side-effects with this approach may further
enhance compliance and outcome.
PMID- 9764130
TI - Analysis of the initial treatment phase in first-episode psychosis.
AB - BACKGROUND: The Early Psychosis Prevention and Intervention Centre (EPPIC)
commenced operation in Melbourne, Australia, in 1992. It offers a model for
management of first-episode psychosis, utilising principles of early detection,
low-dose medication and comprehensive psychosocial interventions within the least
restrictive setting. METHOD: Data were examined from the first three months of
treatment for all consecutive people with first-episode psychosis (n = 231)
accepted in the programme in 1995-1996. A subsample of patients (n = 120) was
assessed comparing clinical ratings with variables of gender, diagnosis,
hospitalisation, and medication. RESULTS: Hospitalisations were brief, and
avoided for a third of the people. Low-dose antipsychotic medication was
maintained in both in-patient and community settings. Those people with manic
psychosis were more likely to be hospitalised. Hospitalised people received
higher antipsychotic dosages, and had a greater rate of reduction in Brief
Psychiatric Rating Scale psychotic subscale scores at three months follow-up.
Eighty per cent of a representative subsample had responded to treatment and 63%
were in remission by the end of the three months. CONCLUSION: This naturalistic
study suggests that the feasibility of implementing the EPPIC model in a range of
clinical settings is promising and applicable in practice.
PMID- 9764131
TI - First-episode schizophrenia. Early intervention and medication discontinuation in
the context of course and treatment.
AB - BACKGROUND: The concept that early intervention with antipsychotic medications
improves the long-term course of schizophrenia is discussed. METHOD: This report
reviews the literature concerning early intervention with antipsychotic
medications for people with first episodes, and how it affects long-term
morbidity. It also studies the effects of discontinuing antipsychotic medications
on relapse for people with first episodes. RESULTS: Early intervention with
antipsychotic medications appears to decrease the long-term morbidity of
schizophrenia. CONCLUSIONS: Early intervention with antipsychotic medications
should be encouraged for people experiencing their first episode of
schizophrenia. This report proposes that studying the various phases of subject
response to treatment can be helpful in elucidating when antipsychotic
medications should be tapered or withdrawn.
PMID- 9764132
TI - Early intervention, untreated psychosis and the course of early schizophrenia.
AB - BACKGROUND: Studies have proved that early intervention can delay psychotic
relapses, and prevent psychosocial deterioration in people with schizophrenia and
related disorders. METHOD: Our study with young people with recent onset
schizophrenia has shown that an intensive intervention programme had a beneficial
effect on the occurrence of psychotic relapse and the course of psychotic
syndromes. This effect lasted until the end of the 15-month intervention. No
significant effect of the two different intervention conditions became apparent.
RESULTS: The results of a follow-up study showed that this beneficial effect did
not last. Fifteen per cent of the people had a psychotic relapse during the
intervention, whereas 64% relapsed during follow-up. CONCLUSIONS: These results
show that referral to other mental health agencies after intervention is not
sufficient and that more support is required to continue disease management,
medication compliance and stress management.
PMID- 9764133
TI - Depression in people with first-episode schizophrenia.
AB - BACKGROUND: Depression has been described in people presenting with first-episode
schizophrenia, a group at high relative risk of suicide. METHOD: This was a
longitudinal cohort study of 113 people during an acute relapse and 13 having a
first episode. Follow-up occurred at three months and at one year. This report
compares level of depression in the first episode and in the relapsing group.
Levels of depression were assessed using the Calgary Depression Scale for
Schizophrenia (CDSS). RESULTS: The median CDSS score was statistically
significantly higher in the first-episode group both during the acute phase and
at three month follow-up. At one year the first-episode group continued to have
higher levels of depression than the multiple episode group. CONCLUSIONS: For
people with a first episode of schizophrenia, depression is a major problem
during the initial acute phase and during the first year of illness. In light of
the high risk of suicide in this population, recognition and treatment of
depression requires greater attention.
PMID- 9764134
TI - Cognitively-oriented psychotherapy for early psychosis (COPE). Preliminary
results.
AB - BACKGROUND: The present study describes the results of the pilot testing of a
therapy we have developed for people with first-episode psychosis. Cognitively
oriented psychotherapy for early psychosis (COPE) is aimed at facilitating the
adjustment of the person, and at preventing or alleviating secondary morbidity in
the wake of the first psychotic episode. METHOD: Eighty people formed three
groups: those who were offered and accepted COPE (COPE subjects); those who
refused COPE (refusal subjects); and those who were offered neither COPE nor any
other continuing treatment from our service (control subjects). The individuals
were assessed prior to, and at the end of, COPE treatment (a 12-month period) on
the Integration/Sealing Over, Explanatory Model, Scale for the Assessment of
Negative Symptoms, Brief Psychiatric Rating Scale, Quality of Life, SCL-90-R, and
Beck Depression Inventory measures. RESULTS: People who received COPE obtained
significantly superior scores (P < 0.05) to the control group on four of the
seven measures but only significantly out-performed the refusal group on one of
the seven measures (P < 0.05). The COPE group performed significantly worse on
the BDI than the refusal group (P < 0.05). Effect sizes are also provided for
each measure. CONCLUSIONS: There seems to be a place for psychological therapy in
this group of people but our results need to be replicated in a more definitive
randomised controlled trial and such a study is now in progress.
PMID- 9764135
TI - Individual cognitive-behavioural interventions in early psychosis.
AB - BACKGROUND: Cognitive-behavioural treatments have previously been explored in the
treatment of chronic psychotic problems, but recently, the effectiveness of these
treatments has been investigated with regard to recent onset and acute psychosis.
METHOD: The literature relating to cognitive-behavioural treatments in psychosis
is explored and the application of the approach to recent onset psychosis is
described in detail. RESULTS: There appears to be a growing body of evidence that
the advances made in the treatment of people with chronic treatment resistant
psychosis can be similarly applied to people with recent onset and acute
psychosis. CONCLUSIONS: Cognitive-behavioural treatments are feasible with recent
onset psychotic patients although further evaluation of their effectiveness is
necessary.
PMID- 9764136
TI - Prolonged recovery in first-episode psychosis.
AB - BACKGROUND: Early identification and specialised treatment of individuals with
enduring positive symptoms may assist in alleviating symptoms and has the
potential to change the course of illness. METHOD: Prevalence and descriptive
data on enduring positive symptoms in two first-episode samples are outlined.
Attempts to incorporate the focus of early intervention for persisting psychosis
into routine clinical care of individuals with first-episode psychosis are
described. RESULTS: Of the 227 individuals with first-episode psychosis who were
assessed using the Brief Psychiatric Rating Scale at 3/6 months and 12 months
following initial stabilisation (from a total sample of 347), 6.6% experienced
enduring positive symptoms at all three time points. When the analysis was
restricted to schizophrenia, schizophreniform and schizoaffective disorders (n =
158) the percentage increased to 8.9%. These patients had significantly longer
mean duration of untreated psychosis prior to initiation of treatment and, at 12
month follow-up, significantly higher depression and poorer psychosocial
functioning. CONCLUSIONS: The association of untreated psychosis with treatment
resistance supports the argument for early intervention as soon as possible
following the onset of psychotic symptoms.
PMID- 9764137
TI - Group programmes for recovery from early psychosis.
AB - BACKGROUND: We evaluate the impact of a group-based, transitional, psychosocial
programme, within a comprehensive service (the Early Psychosis Prevention and
Intervention Centre, EPPIC), on recovery from first-episode psychosis. METHOD:
Individuals using the service (and meeting study criteria) were assessed on a
range of symptom and functioning instruments at entry, after 6 weeks and 6
months. Participants received comprehensive case management and services
according to their identified needs. Thirty-four people who had attended the
group programme were compared at 6 month follow-up with 61 EPPIC patients who had
not attended. RESULTS: The people attending the group programme had a lower level
of premorbid adjustment than the comparison group, and a trend towards exhibiting
a higher level of negative symptoms, prior to commencing the group programme.
However, at 6 month follow-up, no significant differences were found between the
groups. CONCLUSIONS: Involvement in the group programme may have had a positive
impact on a subgroup of EPPIC subjects with poor level of premorbid adjustment,
by providing a 'holding pattern' in the critical period following the emergence
of first-onset psychosis, and thus prevented deterioration and the development of
disability.
PMID- 9764138
TI - Stress and coping in early psychosis. Role of symptoms, self-efficacy, and social
support in coping with stress.
AB - BACKGROUND: Although coping with stress is important in early psychosis, little
is known about how this population copes with the range of stressors they
encounter in their daily life. This study aims to identify how people with early
psychosis cope with a range of stressful situations and to identify what factors
might influence their use of coping strategies. METHOD: Participants included a
clinical group of 50 people with early psychosis and a non-clinical group of 22
people matched on age and gender. Data were obtained on symptomatology and social
support for the clinical group, and stress and coping, and self-efficacy for all
participants. RESULTS: The clinical group reported coping less well than the non
clinical group and they most commonly used emotion-focused coping. For the
clinical group, effective coping correlated with less severe negative symptoms,
greater perceived self-efficacy, social support and greater use of problem
focused coping. Self-efficacy and social support predicted increased frequency of
the use of problem-focused coping. CONCLUSION: People with early psychosis who
have greater feelings of self-efficacy and perceived social support, and the
flexible use of problem-focused coping strategies, appear to be more likely to
cope with day-to-day stressors.
PMID- 9764139
TI - Emotional management therapy in early psychosis.
AB - BACKGROUND: Emotional management therapy (EMT) aims to improve handling of
emotional stress in schizophrenia. It consists of two sub-programmes: the first
includes relaxation techniques, the second stress coping skills. METHOD: A pilot
study of EMT in 19 patients with early psychosis produced positive results and a
post-hoc study of 16 patients was commenced. RESULTS: EMT showed positive
results, with chronic patients improving more than patients with early psychosis.
CONCLUSION: EMT can be effective in early psychosis, especially for cognitive
functioning.
PMID- 9764140
TI - Effect of substance misuse in early psychosis.
AB - BACKGROUND: Studies examining the temporal relationship between substance use and
the onset of psychotic symptoms in schizophrenia are inconclusive. METHOD: Three
groups of out-patients with schizophrenia were compared on onset of illness,
symptoms and quality of life. Fifty-one subjects had no past or present history
of substance misuse, 29 subjects had a history of past substance misuse occurring
around the onset of their illness, and 33 subjects were currently misusing
substances. RESULTS: Current substance misusers had poorer quality of life scores
and less negative symptoms than the non-users. Those who had a past history of
substance misuse had a significantly earlier age of onset than those with no
substance use. CONCLUSIONS: Attention should be paid to substance misuse present
at the first episode. Treatment for schizophrenia should begin even though a
diagnosis of drug-induced psychosis cannot be ruled out.
PMID- 9764141
TI - p53-dependent DNA repair and apoptosis respond differently to high- and low-dose
ultraviolet radiation.
AB - p53 plays an essential part in the maintenance of the cellular genetic stability
after a DNA-damaging event such as ultraviolet (UV) radiation. Following UV
radiation, the amount of p53 protein is elevated. The increased p53 is believed
to induce cell cycle arrest, promote nucleotide excision repair (NER) and
apoptosis. To study if cells respond differently to high- and low-dose UV
radiation, we examined the DNA repair efficiency and apoptosis rate of human and
murine fibroblasts after UV radiation. Using a host cell reactivation assay, we
found that NER was increased after low doses but not after high doses of UV
radiation. In contrast, apoptosis occurred only after the cells received high
doses (over 200 J/m2), but not low doses of UVB. The induction of both NER and
apoptosis was observed only in p53+/+ murine fibroblasts, not in p53-/- cells,
indicating that both stress response mechanisms are dependent on wild-type p53
function. UV radiation induced the expression of p53 protein in a dose-dependent
manner up to 400 J/m2. In contrast, p21waf1/cip1 was induced only after low doses
and bax only after high doses of UV radiation, supporting the roles of
p21waf1/cip1 and bax in NER and apoptosis, respectively. Taken together, these
results indicate that cellular stress response to UV radiation depends on UV
dose, DNA repair after low doses and apoptosis after high doses, and that both
mechanisms are dependent on wild-type p53 function.
PMID- 9764142
TI - Protein kinase C isoform levels in normal and sodium dodecyl sulphate-irritated
mouse skin.
AB - Protein kinase C (PKC) comprises a family of related phospholipid-dependent
serine/threonine protein kinases. PKC is important in signal transduction,
regulating cell proliferation and differentiation. Recently, it has also been
suggested that PKC may play a part in the pathogenesis of contact dermatitis.
However, the expression of PKC isoforms in the skin of mice with irritant contact
dermatitis (ICD) has not been examined. In this study, ICD was induced in mouse
skin by applying 5%, 10% and 20% sodium dodecyl sulphate (SDS) in Finn chambers
on the backs of mice and fixing with surgical dressings for 24 h. Depending upon
the SDS concentration, mild to strong skin irritant reactions were observed 24 h
after removal of the irritant patches. The intensity of the reactions increased
with the increasing concentration of SDS. PKC isoforms alpha, beta, gamma and
delta were all detected in normal mouse skin by Western immunoblotting. The
specificity of the PKC isoforms detected was identified further by competitive
Western immunoblotting. Compared with normal mouse skin treated with double
distilled water, the levels of PKC isoforms alpha, beta, gamma and delta in the
SDS-irritated mouse skin was decreased by 24.8-75.8%. These results suggest that,
in SDS-ICD, mouse skin PKC isoforms alpha, beta, gamma and delta are down
regulated. The significance of this decrease is under further investigation.
PMID- 9764143
TI - Cyclosporin A inhibits 12-O-tetradecanoyl-phorbol-13-acetate-induced cutaneous
inflammation in severe combined immunodeficient mice that lack functional
lymphocytes.
AB - A single application of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) to mouse skin
results in an acute inflammatory response, with an influx of neutrophils and
lymphocytes, epidermal hyperplasia and abnormal keratinocyte differentiation.
This response is significantly inhibited by topical cyclosporin A (CyA). Although
CyA is known to inhibit T-cell activation, the role of T cells in TPA-induced
cutaneous inflammation is not well understood. In this study, we have used severe
combined immunodeficient (SCID) mice, which carry a spontaneous mutation
resulting in the absence of functional T and B lymphocytes, to examine whether
lymphocytes are required for the TPA response in mouse skin and whether CyA
inhibits the TPA response in SCID mice. A significant increase in epidermal and
deep dermal inflammation was observed in both SCID and CB-17 mice 24 h after a
single application of TPA (10 nmol) compared with vehicle (P < 0.05, n = 5-7).
Simultaneous application of CyA (1.7 mumol) plus TPA resulted in a significant
reduction in epidermal and deep inflammation at 24 h compared with TPA alone in
SCID and CB-17 mice (P < 0.05, n = 7). In contrast to hairless mice, a variable
increase in epidermal thickness was observed in both SCID and CB-17 mice after
treatment with TPA at 24 and 72 h, which was not significantly affected by CyA.
These data indicate that TPA-induced inflammation in mouse skin does not depend
on lymphocytes. In addition, the inhibition of TPA-induced epidermal and deep
dermal inflammation by CyA in SCID mouse skin suggests that CyA exerts effects on
cutaneous inflammation in mice in the absence of functioning T cells.
PMID- 9764144
TI - Demonstration of increased levels of type I collagen mRNA using quantitative
polymerase chain reaction in fibrotic and granulomatous skin diseases.
AB - Collagen changes occur in localized scleroderma, scleredema and sarcoidosis.
Previous biochemical, immunohistochemical and in situ hybridization studies have
revealed increased collagen synthesis in these diseases. In the present study, we
measured by pro alpha 1 (I) collagen and beta-actin mRNA levels in skin punch
biopsy specimens from lesional and healthy skin using a quantitative polymerase
chain reaction (PCR). In this method, the targeted mRNA and a synthetic RNA as a
internal standard are co-amplified together with the same primers. The amount of
pro alpha 1 (I) collagen mRNA in cutaneous sarcoidosis lesions was found to be
increased about two- to threefold compared with the values obtained for the
healthy skin of the same two patients. In lesional skin of three patients with
localized scleroderma the number of pro alpha 1 (I) collagen molecules was
increased about two-fold. The beta-actin mRNA values were at the same level in
the affected and unaffected skin of all the patients studied. In conclusion, a
marked increase in type I collagen gene expression was seen in localized
scleroderma and scleredema, leading to fibrosis of the skin, and in a
granulomatous skin disease, cutaneous sarcoidosis.
PMID- 9764145
TI - Blister fluid for the diagnosis of subepidermal immunobullous diseases: a
comparative study of basement membrane zone autoantibodies detected in blister
fluid and serum.
AB - The subepidermal immunobullous diseases bullous pemphigoid (BP), cicatricial
pemphigoid (CP), pemphigoid gestationis (PG) and linear IgA disease (LAD) are
characterized by circulating and in vivo deposition of antibodies to antigens in
the cutaneous basement membrane zone (BMZ). Indirect immunofluorescence (IMF) of
serum is a routine diagnostic test to detect circulating BMZ antibodies in these
diseases. We have compared the titres of IgG and IgA and their subclasses, also
of IgM and IgE BMZ antibodies in serum and aspirated blister fluid in 35 adult
patients with subepidermal immunobullous diseases: BP (n = 30), PG (n = 2), CP (n
= 1), and LAD (n = 2), by indirect IMF on intact and salt-split skin. The
antibody titre in blister fluid was the same or one dilution less than serum in
most cases and there was no significant difference between these results (P >
0.05). IgG1 and IgG4 were the predominant subclasses in both blister fluid and
serum in BP. Indirect IMF of serum and blister fluid was also carried out on
trypsinized epidermal cells in a subgroup of patients with BP (n = 19). Typical
polar fluorescence was obtained in all 14 cases which had positive indirect IMF
on intact and split skin. Our findings demonstrate that blister fluid can be used
as an alternative to serum for indirect IMF in subepidermal immunobullous
diseases. This avoids the need for venesection and has a practical application in
children and those with poor venous access.
PMID- 9764146
TI - Dermatological findings correlated with CD4 lymphocyte counts in a prospective 3
year study of 1161 patients with human immunodeficiency virus disease
predominantly acquired through intravenous drug abuse.
AB - Several prospective studies on dermatological findings in human immunodeficiency
virus (HIV) type 1 infected patients have been published, mostly in populations
in which the predominant risk factor for HIV infection is homosexuality. We
attempted to identify cutaneous diseases associated with HIV-1 infection and to
assess disease progression in a cohort of Spanish patients in whom the
predominant cause of HIV infection was intravenous drug abuse. We prospectively
examined 1161 HIV-1-positive patients for 38 months. Seventy-four per cent of
patients were intravenous drug abusers, whereas heterosexual contact was the only
risk factor in 14% and homosexuality in 9%. Centers for Disease Control stage II
disease predominated (51%), whereas stage IV disease was less frequent (39%). The
mean CD4 count was 353/mm3. We took patients' past and present medical history
and performed a complete physical examination as well as taking photographs and
carrying out the necessary diagnostic procedures. CD4 counts/mm3 were measured at
each visit. A diagnosis of cutaneous disease was made in 799 patients (69%). Oral
candidiasis and seborrhoeic dermatitis were the most common skin disorders,
followed by xerosis, drug eruptions, dermatophytosis and the papular eruption of
acquired immunodeficiency syndrome. Condyloma acuminatum, herpes zoster and
herpes simplex were the most frequent viral infections. Conditions that have a
statistically significant association with advanced stage and low CD4 levels
include drug eruptions, xerosis, light reactions, diffuse alopecia, herpes
simplex, oral candidiasis, psoriasis, oral hairy leucoplakia, molluscum
contagiosum, Kaposi's sarcoma, furuncles, candidal intertrigo, folliculitis and
ungual infection, as well as onychomycosis and tinea pedis or manuum. Dermatoses
commonly associated with homosexuality, such as Kaposi's sarcoma and oral hairy
leucoplakia, were rare in our patients.
PMID- 9764147
TI - Proliferation and differentiation of organoid hair follicle cells co-cultured
with fat cells in collagen gel matrix culture.
AB - Using rat skin, we studied the influence of fat cells on the proliferation and
differentiation of organoid hair follicle cells in a three-dimensional collagen
gel matrix culture system. We cultured organoid hair follicles embedded in
collagen gel under each of the following three conditions: cell-free collagen gel
for control experiments (condition 1); co-culture with fat cells in close
apposition (condition 2); and co-culture with fat cells in spatial separation
(condition 3). Outgrowths of epithelial cells from the organoid hair follicles
associated with perifollicular proliferation of fibroblasts were observed under
conditions 1 and 3. Under condition 2, proliferation of both organoid hair
follicle cells and fibroblasts was inhibited, but differentiation of the hair
follicle cells appeared to be accelerated. Fat cells are considered to have an
inhibitory effect on the proliferation of perifollicular fibroblasts, which might
have resulted in the inhibition of hair follicle cell proliferation and also in
the better maintenance of normal follicular structure and integrity, allowing for
hair-type differentiation to proceed. A direct accelerating effect of fat cells
on hair follicle differentiation may also have been responsible. In a
physiological state (co-culture with keratinocytes on the collagen gel), similar
results were observed under conditions 1 and 2. The different findings under
conditions 2 and 3 may be due to either of two possibilities: either the
concentration gradient of the soluble factors released from fat cells, acting on
either the hair follicle cells or the perifollicular fibroblasts as an inhibitor
of proliferation, caused the difference in the results, or direct contact between
the organoid hair follicle cells and fat cells may have influenced the
accelerating effect of fat cells on the differentiation of hair follicle cells.
PMID- 9764149
TI - Potential psychological benefits from early treatment of port-wine stains in
children.
AB - There is a commonly held conception among referring doctors that very small
children with congenital capillary malformations, so-called port-wine stains
(PWS), should not be treated until they are older. Our experience leads us to
believe that the flashlamp pulsed dye laser is a safe and effective treatment
even for infants. We have not encountered any persistent pigmentation changes,
post-treatment scarring or other adverse effects. It is important to quantify the
psychological disabilities associated with this disorder to assess the need for
and the benefits of treatment. Questionnaires were distributed to 259 patients
and their families who visited our clinic because of their PWS. Patients who were
on the waiting list for laser treatment, undergoing treatment or had completed
their treatment received different questionnaires. The response rate was 89%.
High emotional distress was encountered. During the age period 10-20 years, 73%
(125 patients) were most disturbed by their PWS. That the PWS influenced their
life negatively was experienced by 75% (171 patients), and 62% (106 patients)
were convinced that their life would change radically if their PWS could be
eliminated. Suffering from low self-esteem (in comparison with the same age
group) was reported by 47% (87% patients). The PWS made their school life and
education more difficult according to 28% (51 patients) of the sample. Of the
families of patients, 76% (106 relatives) considered the patient to be negatively
affected in some way by the PWS. After the laser treatment, all of these distress
parameters were significantly relieved, together with a need to cover their PWS,
their fear of going into conflict or quarrels, their social relationships,
problems with the opposite sex, rage attacks, depressions and abnormal reactions
from their peers. We believe there is potential psychological benefit in starting
the treatments of PWS (including non-facial) at as early an age as possible.
PMID- 9764148
TI - The use of skin testing in the investigation of cutaneous adverse drug reactions.
AB - Skin testing with the suspected compound has been reported to be helpful in
determining the cause of cutaneous adverse drug reactions (ADRs), but the value
and specificity of these tests need to be determined. In this study, 72 patients
with presumed drug eruptions (27 maculopapular, 18 urticarial, seven
erythrodermic, nine eczematous, four photosensitivity, three fixed drug
eruptions, three with pruritus and one with acute generalized exanthematous
pustulosis) were assessed. All had drug patch tests; 46 also had prick tests and
30 had intradermal tests (performed on hospitalized patients using a sterile
solution of the suspected drug, diluted sequentially) with immediate and delayed
readings. Among these patients, 52 (72%) had a positive skin test reaction, 43%,
24% and 67% in patch, prick and intradermal skin tests, respectively. The results
of skin tests varied with the drug tested and with the clinical type of cutaneous
ADR, as a significantly higher number of positive patch tests was observed in
maculopapular rashes than in urticarial reactions (P = 0.001). This study
supports the value of careful sequential drug skin testing in establishing the
cause of cutaneous ADR. Guidelines are proposed for performing these tests, and
these include the use of appropriate negative control patients to avoid false
positive results.
PMID- 9764150
TI - The management of established postherpetic neuralgia: a comparison of the quality
and content of traditional vs. systematic reviews.
AB - In the face of an exponential increase in published biomedical studies,
dermatologists frequently turn to review articles in order to keep abreast of
important developments in the treatment of skin diseases. Traditional review
articles have recently been criticized on the basis of their incompleteness and
susceptibility to bias. Such biases can be minimized by employing a systematic
approach to gathering, combining and interpreting the evidence of treatment
efficacy. Using eight predetermined quality criteria, we compared the quality of
10 traditional review with one systematic review of treatments for postherpetic
neuralgia, which were identified from the Medline database for 1992-96. None of
the 10 traditional review articles satisfied all eight criteria: one satisfied
five, two satisfied four and the rest satisfied two or fewer criteria. There was
a wide variation in the recommendations of the authors for the treatment of
postherpetic neuralgia, often based on anecdotal evidence and clinical
experience. On the other hand, the systematic review fulfilled seven of the eight
quality criteria, failing only to discuss future directives. Furthermore,
treatment recommendations were made solely on the basis of randomized controlled
trials, which are considered to be the gold standard for measuring the benefits
of any intervention. The variation in quality and treatment recommendations of
traditional reviews is worrying. Systematic reviews should be encouraged in
dermatology because they provide a summary of evidence of the effects of
dermatological treatments, which has been derived using explicit methods widely
accepted within science.
PMID- 9764151
TI - Severity distribution of atopic dermatitis in the community and its relationship
to secondary referral.
AB - Although atopic dermatitis is the most common inflammatory dermatosis affecting
children, no previous studies have evaluated the relationship between disease
severity and the referral pattern to secondary health care services. We carried
out a cross-sectional survey of 1760 children aged 1-5 years selected from the
age-sex registers of four urban and semiurban general practices in Nottingham.
Atopic dermatitis was diagnosed by a dermatologist on the basis of symptoms and
signs of a flexural itchy rash that had been present in the previous 12 months.
The severity of atopic dermatitis was assessed clinically by the same
dermatologist on the basis of reported symptoms over the previous 12 months and
clinical signs, and was graded on a three-point scale as mild, moderate or
severe. Information on the use of primary and secondary health care services was
recorded at the time of the interview. The 1-year period prevalence of atopic
dermatitis was 16.5% (95% confidence interval 14.7-18.2%). The severity
distribution of atopic dermatitis was: mild 84% (n = 242), moderate 14% (n = 41)
and severe 2% (n = 7). Of those children with atopic dermatitis, 96% (n = 278)
had consulted their general practitioner in the previous 12 months and 6% (n =
17) had been seen in secondary care. Overall, 4% (n = 11) of those children with
atopic dermatitis had a consultation with a dermatologist. Other sources of
secondary care referral included the paediatric department (n = 2) and accident
and emergency department (n = 6). Referral to secondary care was found to be
positively related to disease severity, with referral occurring in 3% of mild
cases, 15% of moderate cases and 43% of severe cases. Although the relative
referral rate of mild and moderately severe disease was low, these cases were
found to represent a significant proportion (82%) of the total numbers of
children seen in secondary care. This study has shown that: (i) most cases of
atopic dermatitis in the community are mild in severity; (ii) referral to
secondary health care services by general practitioners is infrequent; (iii)
disease severity is an important determinant of referral to secondary care; and
(iv) any potential change in the referral pattern of mild/moderate cases of
atopic dermatitis to secondary care is likely to produce a significant increase
in workload for dermatology departments.
PMID- 9764152
TI - Prescribing for out-patients by nursing staff in a dermatology department.
AB - Nurse prescribing for a small range of products has been introduced in primary
care, but not in hospitals, in the U.K. We have evaluated the benefits, costs,
practicality and patient satisfaction with the formal introduction of dermatology
nurse prescribing in the out-patient treatment facility of a district general
hospital dermatology department with a wide geographical catchment area. Over a 6
month period, 91 items were prescribed to 47 patients on 72 occasions
(items/patient: range 1-8, mean 2, median 1). The cost to the department was
249.04 Pounds (cost per patient: range 0.39 Pound-24.61 Pounds, mean 5.30
Pounds). A small number of patients appeared to use nurse prescribing as a
substitute for medical consultations. A total of 33 of 45 adult patients replied
to a questionnaire. In 15 respondents, the prescription was necessitated by a
change in the skin condition and in 10 by the exhaustion of supplies of the
current medication, and both of these factors applied in six patients. All had
understood the instructions for the use of the treatment prescribed, and only
three felt that it had failed to work as anticipated. Only one patient had
(unspecified) side-effects, caused by a prescription for a topical antipruritic.
Eight patients were able to defer appointments with their general practitioner as
a result of the nurse-prescribed item being supplied. Prescribing by
appropriately trained nurses therefore appears to be a safe and effective
development in dermatology.
PMID- 9764153
TI - Comparison of teleconsultations and face-to-face consultations: preliminary
results of a United Kingdom multicentre teledermatology study.
AB - The objective of this multicentre study was to undertake a systematic comparison
of face-to-face consultations and teleconsultations performed using low-cost
videoconferencing equipment. One hundred and twenty-six patients were enrolled by
their general practitioners across three sites. Each patient underwent a
teleconsultation with a distant dermatologist followed by a traditional face-to
face consultation with a dermatologist. The main outcome measures were diagnostic
concordance rates, management plans and patient and doctor satisfaction. One
hundred and fifty-five diagnoses were identified by the face-to-face
consultations from the sample of 126 patients. Identical diagnoses were recorded
from both types of consultation in 59% of cases. Teledermatology consultations
missed a secondary diagnosis in 6% of cases and were unable to make a useful
diagnosis in 11% of cases. Wrong diagnoses were made by the teledermatologist in
4% of cases. Dermatologists were able to make a definitive diagnosis by face-to
face consultations in significantly more cases than by teleconsultations (P =
0.001). Where both types of consultation resulted in a single diagnosis there was
a high level of agreement (kappa = 0.96, lower 95% confidence limit 0.91-1.00).
Overall follow-up rates from both types of consultation were almost identical.
Fifty per cent of patients seen could have been managed using a single
videoconferenced teleconsultation without any requirement for further specialist
intervention. Patients reported high levels of satisfaction with the
teleconsultations. General practitioners reported that 75% of the
teleconsultations were of educational benefit. This study illustrates the
potential of telemedicine to diagnose and manage dermatology cases referred from
primary care. Once the problem of image quality has been addressed, further
studies will be required to investigate the cost-effectiveness of a
teledermatology service and the potential consequences for the provision of
dermatological services in the U.K.
PMID- 9764154
TI - A randomized, double-blind study comparing the efficacy, safety and optimal dose
of two formulations of cyclosporin, Neoral and Sandimmun, in patients with severe
psoriasis. OLP302 Study Group.
AB - This study compared the efficacy, safety and optimal dose of two formulations of
cyclosporin, Sandimmun and Neoral, in patients with severe, chronic plaque-type
psoriasis. Patients were randomized on a 1:1 basis to 24 weeks of treatment with
Neoral (n = 152) or Sandimmun (n = 157). The starting dose of each formulation
was 2.5 mg/kg per day. Dose increases to maintain efficacy were allowed after 4
weeks. In patients who achieved remission, the dose was down-titrated at 4-week
intervals from week 16. The maximum permitted dose for each formulation was 5.0
mg/kg per day. Neoral produced a more rapid response than Sandimmun: remission
rates were higher for Neoral during the first 8 weeks of treatment. The number of
dose reductions for safety was similar in both treatment groups, but there were
more dose increases to maintain efficacy in the Sandimmun group (198) than the
Neoral group (146). The number of patients with dose reductions after week 16 was
higher for Neoral (n = 83) than for Sandimmun (n = 73). The frequency and nature
of adverse events were similar for both treatment groups. The mean dose required
to control the disease was approximately 10% lower with Neoral and fewer dose
changes were needed. The increased bioavailability and reduced pharmacokinetic
variability of cyclosporin provided by the Neoral formulation may facilitate
short-course, intermittent therapy.
PMID- 9764155
TI - Deletion pattern of the steroid sulphatase gene in Japanese patients with X
linked ichthyosis.
AB - Most caucasian patients with X-linked ichthyosis (XLI) reportedly display large
genomic deletions involving the entire steroid sulphatase (STS) gene and flanking
regions. In this study, we investigated the deletion patterns of the STS gene and
flanking regions in 12 unrelated Japanese patients with XLI using the polymerase
chain reaction method with 10 markers, including the 5' and 3' ends of the STS
gene. Eleven of the 12 patients exhibited deletion of this entire gene, whereas
the twelfth patient showed no evidence of deletion. In 10 of the 12 patients, the
entire region from DXS1139 to DXF22S1 was deleted, the most common deletion
pattern observed in caucasian patients, indicating that there are no racial or
ethnic differences.
PMID- 9764156
TI - Acne vulgaris in the elderly: the response to low-dose isotretinoin.
AB - There is a very small number of patients who suffer from acne even in the sixth
and seventh decades of life. These patients have suffered from acne for most of
their lives, 30-60 years, and have often received multiple courses of antibiotics
over many years. We saw 10 such patients over 4 years. One received oral
isotretinoin 1 mg/kg per day, but was unable to tolerate the adverse effects of
cheilitis and developed hyperlipidaemia. We subsequently treated nine others with
oral isotretinoin, 0.25 mg/kg per day, for 6 months; in six the acne had
virtually cleared by 3-4 months while the other three cleared by 6 months. Up to
36 months after therapy these patients have remained clear of acne except for one
who relapsed after 11 months. Therefore, as these patients respond well with few
side-effects both in the long- and short-term to low-dose isotretinoin, they
should be treated with isotretinoin, although at the lower starting dose of 0.25
mg/kg per day compared with younger patients who are treated with 0.5-1 mg/kg per
day, and the treatment maintained for 6 months.
PMID- 9764157
TI - Differential response of sebaceous glands to exogenous testosterone.
AB - To test the hypothesis that the seborrhoea of acne is an end-organ hyper-response
to androgens, a standardized dose of 2% testosterone cream was applied to the
forehead of eight prepubertal boys for 6 weeks and the effect determined by
measurements of sebum excretion rate (SER). Three boys showed a 15-fold increase
in SER and three boys were non-responders, whereas two boys had SER values
between those of the responders and non-responders. These data show that
sebaceous glands are stimulated by androgens to varying degrees and support the
theory of an end-organ response in acne.
PMID- 9764158
TI - Itraconazole oral solution for the treatment of tinea capitis.
AB - Twenty-seven children (12 boys, 15 girls, age range 3-11 years, weight range 10
40 kg) were treated with itraconazole oral solution 10 mg/mL given as pulse
therapy for tinea capitis. The dosage regimen was 3 mg/kg per day given once
daily in a fasting state with each pulse lasting 1 week. The first two pulses
were separated by a 2-week off-drug period, and the second and third pulses had a
3-week period without drug between them. For each patient a second and third
pulse were administered if there was clinical evidence of tinea capitis at the
time-point when the next pulse was due. The overall severity of tinea capitis at
pretherapy was classified as mild, moderate or severe with the aetiology being:
Trichophyton tonsurans, 24 patients; T. violaceum, two patients and Microsporum
canis, one patient. In 19 evaluable patients, 12 weeks after starting therapy,
the numbers of pulses of itraconazole oral solution required to produce complete
cure were, according to the severity of disease, mild tinea capitis (one pulse:
four patients; two pulses: five), moderate disease (one pulse: two patients; two
pulses: two; three pulses: two), and severe disease (three pulses: three
patients). One patient with moderate severity tinea capitis was clinically clear
after three pulses of therapy but mycological examination was positive. Seven
patients were lost to follow-up and one discontinued therapy because of nausea.
Itraconazole oral solution 3 mg/kg per day was generally well tolerated. Three
children developed gastrointestinal adverse effects which were considered to be
minor or 'nuisance' effects. The data from this preliminary report need to be
confirmed in a larger group of patients. It remains to be seen whether
itraconazole oral solution will become a practical alternative to the antifungal
agents available in a liquid preparation for the treatment of tinea capitis.
PMID- 9764159
TI - Sweet's syndrome associated with non-tuberculous mycobacterial infection: a
report of five cases.
AB - We report the rare association of Sweet's syndrome with non-tuberculous
mycobacteria in five patients (three women, two men, aged 25-41 years). Clinical
and histological evidence supported the diagnosis of Sweet's syndrome in all
patients. The skin lesions responded well to systemic corticosteroid but recurred
in two cases. All of our patients had chronic disseminated non-tuberculous
mycobacterial infection. They initially presented with lymphadenopathy and
developed involvement in other organs later. All of them were treated as having
tuberculous lymphadenitis based on pathological findings before definite
diagnosis was made by culture. The organisms isolated were Mycobacterium chelonae
in three cases, M. scrofulaceum in one case and M. avium intracellulare complex
in one case. All the patients gradually improved with treatment but one had
multiple recurrences. The search for an infectious agent, especially non
tuberculous mycobacteria, should be performed in cases of Sweet's syndrome that
appear in association with chronic granulomatous lymphadenitis which is
recalcitrant to antituberculous drugs.
PMID- 9764160
TI - Unusual clinical variants of cutaneous leishmaniasis in Pakistan.
AB - Cutaneous leishmaniasis is endemic in the Baluchistan province of Pakistan and
poses a great risk to non-immune visitors to the area. The wide spectrum of
clinical variants of this common disease is at times a diagnostic challenge. A
total of 1709 patients with cutaneous leishmaniasis were recorded over a 1-year
period. In 37 (2%) patients the lesions were very unusual, and therefore worth
reporting. These included acute paronychial, chancriform, annular, palmoplantar,
zosteriform and erysipeloid forms. The zosteriform and erysipeloid forms have
rarely been reported previously, but to the best of our knowledge, acute
paronychial, chancriform, annular and palmoplantar lesions are being reported for
the first time. The morphologically unusual lesions may be attributed to an
altered host response or involvement of an atypical strain of parasite in these
lesions.
PMID- 9764161
TI - Visceral leishmaniasis with cutaneous lesions in a patient infected with human
immunodeficiency virus.
AB - We report a case of visceral leishmaniasis (VL) with cutaneous lesions in a
patient infected with human immunodeficiency virus (HIV). The cutaneous lesions
consisted of erythematous papules on the legs. Biopsy of one lesion showed
abundant Leishmania amastigotes within epithelial cells of an eccrine sweat gland
in the dermis. Leishmania organisms were also found in a blood smear. Rapid and
complete clearance of the cutaneous lesions was achieved after antimony therapy.
Cutaneous lesions in VL are being reported increasingly frequently in patients
with HIV infection and their significance remains in discussion.
PMID- 9764162
TI - Pseudotumour of the tongue caused by herpes simplex virus type 2 in an HIV-1
infected immunosuppressed patient.
AB - An HIV-1 infected immunosuppressed patient (CD4+ cell counts: 382 cells/microL;
viral load 94,000 copies/mL) with recurrent perianal herpes simplex virus type 2
(HSV-2) infections is described, showing an unusual exophytic tumour resembling a
squamous cell carcinoma in the lateral part of the tongue. He also had persistent
facial herpes infection, oral candidosis, oral hairy leukoplakia and
lymphadenopathy. The presence of HSV-2 was detected by polymerase chain reaction
both in smears and in a tissue biopsy taken from the involved tongue area.
Treatment with brivudin, a new oral virustatic drug, led to rapid regression of
the tumour.
PMID- 9764163
TI - Epidermodysplasia verruciformis-like eruption complicating human immunodeficiency
virus infection.
AB - Three human immunodeficiency virus (HIV)-infected patients presented with
disseminated pityriasis versicolor-like skin lesions. Histological examination
showed features characteristic of epidermodysplasia verruciformis (EV).
Hybridization studies demonstrated the presence of human papillomavirus (HPV)
type 5 (HPV5) DNA in two patients and HPV20 in one. A relative increase in CD8+,
CD57+ cells, which are known to inhibit cell-mediated cytolysis, was observed in
all patients. HLA-DQB 0301 haplotype, which has been associated with EV, was
detected in two patients. The findings suggest that infection with EV-associated
HPV types can complicate HIV infection. Both cellular immune defects and a
hitherto unknown genetic background might explain the occurrence of EV in HIV
infected patients.
PMID- 9764164
TI - Vulval and vaginal adenosis.
AB - Vaginal adenosis is defined by the presence of metaplastic cervical or
endometrial epithelium within the vaginal wall, thought to be derived from
persistent Mullerian (synonymous with paramesonephric) epithelium islets in
postembryonic life. Spontaneous vaginal adenosis appears to be a fairly common
(present in about 10% of adult women) but mostly insignificant coincidental
finding. In women prenatally exposed to diethylstilboestrol (DES), vaginal
adenosis may arise in up to 90% and is associated with a high risk of vaginal
carcinoma. Since the withdrawal of DES from the market, vaginal adenosis has
virtually disappeared from the medical literature. A case of vaginal adenosis is
presented in a middle-aged woman who had not been prenatally exposed to DES. The
lesions differed from the spontaneous type by their sudden appearance, their
extent and their pronounced subjective symptoms. It is speculated that protracted
oral contraceptive intake may have played a causative role.
PMID- 9764165
TI - Proteus syndrome: diagnosis in adulthood.
AB - We describe a 24-year-old woman with many of the classical features of the
Proteus syndrome. In childhood she had undergone bilateral forefoot amputations
because of massive bilateral cerebriform hypertrophy of the feet. Other features
include abnormally large fingers on one hand, a lymphangioma circumscriptum, an
epidermal naevus, prominent venous varicosities and scattered lipomas. The
disorder occurs sporadically and is thought to be secondary to a postzygotic
mutation that survives by mosaicism.
PMID- 9764166
TI - Trichothiodystrophy without associated neuroectodermal defects.
AB - Trichothiodystrophy leading to generalized trichorrhexis nodosa-like hair changes
with abnormal hair breakage is described in a 4-year-old girl. A marked
deficiency of sulphur and the sulphur-containing amino acid, cystine, was
detected in the biochemical analysis of the hair. Further investigation of the
hair showed the morphological criteria of trichothiodystrophy. Commonly related
symptoms, such as mental retardation, ichthyosis and increased sensitivity to
sunlight, were not present in our patient.
PMID- 9764167
TI - Pseudoxanthoma elasticum-like papillary dermal elastolysis: report of four
Japanese cases and an immunohistochemical study of elastin and fibrillin-1.
AB - We report four patients with pseudoxanthoma elasticum-like papillary dermal
elastolysis (PDE). Multiple small papules on the neck, clinically resembling
pseudoxanthoma elasticum, and loss of the elastic fibre network in the papillary
dermis were found in each case. Immunohistochemical staining for elastin and
fibrillin-1 in one patient demonstrated the disappearance of elastin and
fibrillin-1 in the papillary dermis. Site-matched normal skins of the elderly
showed intact elastin but a lack of fibrillin-1 in the papillary dermis. The
younger normal skins revealed intact elastin and fibrillin-1. The results suggest
that fibrillin-1 is absent from the papillary dermis of the normal-appearing neck
skin of the elderly and that the primary defect in PDE may be in elastin rather
than in fibrillin-1.
PMID- 9764168
TI - Erythropoietic protoporphyria improving during pregnancy.
AB - Erythropoietic protoporphyria is an uncommon disorder which causes a
photosensitive cutaneous reaction, and occasionally hepatic dysfunction in
affected individuals. We report a patient with erythropoietic protoporphyria who
improved symptomatically during her two pregnancies. In the latter pregnancy,
quantitative levels of plasma and erythrocyte protoporphyrins were reduced by
more than half during the pregnancy compared with the levels before pregnancy and
during lactation.
PMID- 9764169
TI - Hyperpigmentation due to topical calcipotriol and photochemotherapy in two
psoriatic patients.
AB - The vitamin D3 analogue calcipotriol (calcipotriene) is an effective topical
treatment for psoriasis. In combination with other antipsoriatic agents, such as
ultraviolet radiation, calcipotriol is reported to improve the overall efficacy
of the treatment. Here we describe two patients treated with a combination
treatment of calcipotriol and bath psoralens and ultraviolet A who developed
hyperpigmentation at the lesional sites where calcipotriol ointment was applied.
PMID- 9764170
TI - Cutaneous lesions in giardiasis. Report of two cases.
PMID- 9764171
TI - Severe acral pruritus associated with parvovirus B19 infection.
PMID- 9764172
TI - Red finger syndrome associated with necrotizing vasculitis in an HIV-infected
patient with hepatitis B.
PMID- 9764173
TI - The prevalence of skin diseases in human immunodeficiency infection and its
relationship to the degree of immunosuppression.
PMID- 9764174
TI - Proximal subungual onychomycosis due to Aspergillus niger: report of two cases.
PMID- 9764175
TI - Exophiala werneckii causing tinea nigra in Scotland.
PMID- 9764176
TI - Bullous pemphigoid blisters of the same duration have similar cytokine
concentrations which decrease in older blisters.
PMID- 9764177
TI - Abrupt onset of severe Behcet's disease: preceding oral ulceration is not
essential for diagnosis.
PMID- 9764178
TI - Panniculitis in dermatomyositis: report of two cases.
PMID- 9764179
TI - Pyoderma gangrenosum associated with myelofibrosis.
PMID- 9764180
TI - Kasabach-Merritt syndrome associated with angioblastoma.
PMID- 9764181
TI - Familial cavernous haemangiomas.
PMID- 9764182
TI - The Woronoff zone surrounding the psoriatic plaque.
PMID- 9764184
TI - Dermatitis simulata.
PMID- 9764183
TI - Severe pustular psoriasis provoked by oral terbinafine.
PMID- 9764185
TI - Quo vadis classical physiology?
PMID- 9764186
TI - Of mice and men--the future of cardiovascular research in the molecular era.
PMID- 9764187
TI - Mouse models of angiogenesis, arterial stenosis, atherosclerosis and hemostasis.
AB - The development of efficient transgenic technologies in mice has allowed the
study of the consequences of genetic alterations on cardiovascular
(patho)physiology, although the development of such models have been hampered by
size limitation of species resulting in time-consuming, labor-intensive and
costly analyses. This overview summarizes the murine models currently available
for studying or manipulating angiogenesis, arterial stenosis, atherosclerosis,
transplant arteriopathy, thrombosis, thrombolysis and bleeding and addresses
techniques to evaluate vascular development during embryogenesis.
PMID- 9764188
TI - Cardiovascular phenotyping in mice.
AB - Progress in molecular genetics has changed cardiovascular research. The mouse has
turned out to be an invaluable model for mammalian genetic modifications to mimic
and analyse cardiovascular pathology. Through the introduction of transgene and
gene targeting technology, regulatory systems can be studied at the molecular
level. Recent technical developments have down-sized the equipment for
physiological measurements to the mouse level. Micro-surgery has developed to the
level where most manipulations previously performed in larger animals can now be
applied to mice. However, different investigators report considerable differences
in values for physiological parameters. Whether these differences are related to
the variation in mouse strains or experimental procedures remains to be
established, but awareness of the variation can be relevant for prospective mouse
investigators. In the present review, the physiological measurements performed in
mice to date are discussed and complemented with results from genetically
manipulated animals. In addition the various surgical procedures and their
practical application are illustrated.
PMID- 9764189
TI - Why do animal models of post-angioplasty restenosis sometimes poorly predict the
outcome of clinical trials?
PMID- 9764190
TI - Animal models of human cardiovascular disease, heart failure and hypertrophy.
AB - The progress made in our understanding of the pathophysiology and treatment of
congestive heart failure (CHF) would not have been possible without a number of
animal models of heart failure and hypertrophy, each one having unique advantages
as well as disadvantages. The species and interventions used to create CHF
depends on the scientific question as well as on factors such as ethical and
economical considerations, accessibility and reproducibility or the model. How
closely the model should mimic the human syndrome of CHF depends on the
scientific question under investigation. If the goal is to study
pathophysiological processes like remodeling or the function of subcellular
systems such as excitation contraction-coupling processes, contractile protein
function or energetics, the model of heart failure should mimic the clinical
setting as closely as possible. However, if defined causal connections are under
investigation such as structure-function analyses or regulation of gene
expression, exact reflection of the clinical setting by the animal model may be
less important. In this review, animal models of heart failure are discussed with
particular focus on similarities between the animal model and the failing human
heart regarding myocardial function as well as molecular and subcellular
mechanisms. In addition, new models of heart failure and hypertrophy, and finally
some recent animal models of myocarditis are reviewed.
PMID- 9764191
TI - Lessons from rat models of hypertension: from Goldblatt to genetic engineering.
AB - Over the past 50 years various animal models of hypertension have been developed,
predominantly in the rat. In this review we discuss the use of the rat as a model
of hypertension, and evaluate what these models have taught us. Interestingly,
the spontaneously hypertensive rat (SHR) is by far the most widely used rat
model, although it reflects only a rare subtype of human hypertension, i.e.
primary hypertension that is inherited in a Mendelian fashion. Many other aspects
of the etiology of hypertension are found in other rat models, but these models
are less frequently employed. The widespread use of the SHR suggests that this
rat model is often chosen without considering alternative (and possibly better
suited) models. To illustrate the importance of the choice for a particular
model, we compared the natural history and response to antihypertensive drugs in
different rat models of hypertension (SHR, Dahl, deoxycorticosterone acetate
(DOCA)-salt, two-kidney one-clip, transgenic TGR(mRen2)27. This revealed that the
outcome of hypertension can be similar in some respects, as all models exhibit
cardiac hypertrophy, and all demonstrate impaired endothelium-dependent
relaxations. However, the more severe forms of end-organ damage such as heart
failure, stroke and kidney failure, occur only in some models and then only in a
subset of the hypertensive rats. The effects of antihypertensives varies even
more in the different models: antihypertensive treatment only attenuates end
organ damage if it decreases blood pressure. Moreover, if a given
antihypertensive is effective, it sometimes even attenuates end-organ damage in
nonhypotensive doses. On the other hand, some agents do decrease blood pressure
but do not prevent end-organ damage (e.g. hydralazine in SHR). Furthermore, not
all classes of antihypertensives are equally effective in all rat models of
hypertension: endothelin-receptor antagonists are not effective in SHR, but have
beneficial effects in the DOCA-salt model. The comparison of models, and the
comparison of treatment effects suggests that end-organ damage critically depends
upon not only on the stress imposed by high blood pressure and its underlying
biochemical disturbance, but also upon the ability of the organism to recruit
adequate 'coping' mechanisms. These coping mechanisms deserve greater attention,
as failure to recruit such mechanisms may indicate an increased risk. The current
development of transgenic techniques will provide new opportunities, to develop
specific models to address this balance between stress and coping.
PMID- 9764192
TI - Rat models of hypertension, cardiac hypertrophy and failure.
PMID- 9764193
TI - Experimental models for the investigation of brain ischemia.
PMID- 9764194
TI - Animal models in the study of myocardial ischaemia and ischaemic syndromes.
PMID- 9764195
TI - Physiopharmacological evaluation of myocardial performance: how to study
modulation by cardiac endothelium and related humoral factors?
PMID- 9764196
TI - Physio-pharmacological evaluation of myocardial performance: an integrative
approach.
PMID- 9764197
TI - The mouse with trisomy 16 as a model of human hearts with common atrioventricular
junction.
AB - OBJECTIVE: To establish if the mouse with trisomy 16 is a suitable animal model
with which to elucidate the development of a common atrioventricular junction.
METHODS: The junctional morphologies in the normal human heart and those with a
common atrioventricular junction are compared and contrasted. These are then
related to observations made in normal mice and those with trisomy 16. So as
better to understand development, a full description is given first of the normal
atrioventricular junctions. Developmental implications are discussed because
failure of fusion of the endocardial cushions cannot account for all the
anomalies found in RXR alpha knockout, and in iv/iv mice. RESULTS: Mice with
trisomy 16 showed evidence of deficiencies of atrioventricular septation and
possessed a common atrioventricular junction, but the valvar orifices were not
balanced between the ventricles as is the case in humans. Whilst some mice showed
affinities with human tricuspid atresia, other cardiac malformations in the mice
had no counterparts in human cardiac pathology. In humans both "partial" and
"complete" forms of "atrioventricular canal malformations" share a basically
common muscular junctional morphology, the differences being due exclusively to
the way the bridging leaflets are fused to each other and/or the septum.
CONCLUSIONS: It is simplistic to use the mouse with trisomy 16 as a model for
cardiac abnormalities seen in humans. A spectrum more comparable to humans is
found in RXR knockout mice. Study of the iv/iv mouse may help elucidate the
genetic steps involved in normal and abnormal atrioventricular septation.
PMID- 9764198
TI - Animal models of cardiac arrhythmias.
PMID- 9764199
TI - Experimental models of torsade de pointes.
AB - Torsade de pointes is a potentially life threatening form of polymorphic
ventricular tachycardia typically seen in the setting of congenital and acquired
abnormal QT-prolongation. Numerous in vitro studies have investigated basic ionic
mechanisms underlying delayed repolarization. The role of different ion channels
and the induction of early afterdepolarizations have been studied in various
cardiac cells including M cells. In addition, isolated heart models with and
without electrical stimulation and/or the use of drugs which prolong
repolarization have been developed in recent years. Some of these models have
simulated conditions likely to exist in the clinical setting of torsade de
pointes, such as bradycardia and hypokalemia. In in vivo canine and rabbit
models, torsade-like polymorphic ventricular tachyarrhythmias have been induced
by the administration of different agents such as cesium, neurotoxins, e.g.,
anthopleurin or various class III drugs under conditions designed to mimic the
clinical situation. In the context of recent advances in the molecular genetics
of long QT syndrome, those models which have used sodium or potassium channel
blockers have gained particular interest. Based on all experimental studies it
seems probable that the first beats of torsade occur due to early
afterdepolarizations and triggered activity. The development of subsequent beats
is less clear. Reentry based on inhomogeneity of refractoriness has been
suggested as the underlying mechanism.
PMID- 9764200
TI - Characterisation, utilisation and clinical relevance of isolated perfused heart
models of ischaemia-induced ventricular fibrillation.
AB - The isolated perfused heart has been used increasingly during the last decade as
a model for identifying actions of drugs on ventricular fibrillation (VF) induced
by myocardial ischaemia. In addition, it has been used to explore the mechanisms
responsible for the initiation and maintenance of VF, the concept of endogenous
myocardial protection and the phenomenon of preconditioning. This article is a
review of the available data (effects of drugs, sources of variation, comparison
with other models and man, etc.) and an attempt to evaluate the possible clinical
relevance. For several reasons, it is not possible to make a precise judgement on
the absolute value of the model in terms of its ability to accurately predict the
effectiveness of drugs in the prevention of sudden cardiac death, the main reason
being the lack of a positive control, i.e. a drug with proven effectiveness
against sudden cardiac death caused by VF in man. Nevertheless, the means by
which one may reliably and reproducibly generate ischaemia-induced VF in
different isolated heart preparations, and the factors (such as species, heart
rate, perfusion constituents and involved zone size) that determine the incidence
of VF are now well documented. Careful selection of species and experimental
conditions permits the isolated heart of smaller inexpensive animals to function
as a first line model for detecting anti-VF activity of probable relevance to
phase 1 arrhythmogenesis (i.e., arrhythmogenesis during the first 30 min of
ischaemia). In view of the absence of a clinical template from which to evaluate
how well it predicts drug effectiveness in man, this model's clinical relevance,
like that of all other preparations and models, can yet be neither accepted nor
dismissed. Recent publication patterns suggest an increasing use of the model.
Therefore, recommendations are made to facilitate its effective use.
PMID- 9764201
TI - A small animal model of non-ischemic cardiomyopathy and its evaluation by
transthoracic echocardiography.
AB - BACKGROUND: Costs for large animal studies have escalated. Therefore there is a
need to develop small animal models of non-ischemic cardiac failure and accurate
non-invasive techniques that will allow serial quantitation of left ventricular
function. OBJECTIVES: The purpose of our study was to determine the efficacy and
reliability of adriamycin for inducing cardiomyopathy in rats. We hypothesized
that high frequency transthoracic 2-dimensional and M-mode echocardiography would
allow for serial testing of cardiac function in this small animal model. METHODS:
Adriamycin was administered at a dose of 2.5 mg/kg intravenously once a week for
10 weeks in 54 rats. Transthoracic echocardiography by use of a 7.5 MHz
transducer was performed in 19 rats at baseline and additionally at 12 weeks
after beginning of adriamycin therapy to measure left ventricular dimensions and
calculate fractional shortening. RESULTS: The mortality rate during the treatment
period was 11%, but increased to 52% at 13 weeks. Transthoracic echocardiography
provided adequate visualization of left ventricular dimensions and cardiac
function in a parasternal short axis view. In follow-up echocardiography,
pericardial effusion was detected in 8/19 rats (42%). Compared to baseline, end
diastolic diameters increased from 0.56 +/- 0.06 to 0.64 +/- 0.08 mm (p < 0.001),
end-systolic diameters increased from 0.27 +/- 0.03 to 0.42 +/- 0.08 mm (p <
0.001), and fractional shortening decreased from 52.8 +/- 4.0 to 34.3 +/- 7.1% (p
< 0.001) at 12 weeks. Electron microscopy in a subset of rats revealed
cardiomyocyte degeneration, mitochondrial and sarcoplasmatic reticular edema,
numerous intracellular vacuoles and 'onion-ring' shaped mitochondrial cristae,
characteristic for adriamycin cardiotoxicity in human patients. CONCLUSION:
Adriamycin at an intravenous dose of 2.5 mg/kg over 10 weeks can be used to
create a reliable model of non-ischemic dilated cardiomyopathy with a high
success rate. For in-vivo diagnostic purposes, transthoracic echocardiography
provides a reliable technique to non-invasively assess cardiac function
quantitatively and qualitatively in follow-up studies in rat cardiomyopathy. This
small animal model can easily be used for testing new therapeutic strategies in
cardiac failure.
PMID- 9764202
TI - The atherosclerotic Yucatan animal model to study the arterial response after
balloon angioplasty: the natural history of remodeling.
AB - OBJECTIVE: Remodeling in de novo atherosclerosis and in restenosis after balloon
angioplasty constitutes a change in total arterial circumference which, together
with plaque growth or neointimal formation, determines the lumen of the artery.
To better understand the fundamental biology of neointimal formation, remodeling
and their interaction, animal studies are needed. In this study, we described in
detail the methodology used and the natural history of neointimal formation and
remodeling after balloon angioplasty in atherosclerotic Yucatan micropigs.
METHODS AND RESULTS: Atherosclerosis was induced in 60 peripheral arteries of
sixteen Yucatan micropigs by a combination of denudation and atherogenic diet.
Balloon angioplasty was performed in 38 arteries, with serial intravascular
ultrasound (IVUS) and quantitative angiography before and after intervention and
at 2, 4, 7, 14 or 42 days follow-up. Remodeling, expressed as late media-bounded
area (MBA) loss, increased progressively over time. At 42 days, late MBA loss
after balloon angioplasty was significantly different compared to late MBA loss
in control arteries, 2.2 +/- 1.0 versus -0.3 +/- 1.1 mm2 and p = 0.02. Late lumen
loss increased over time and was highest at 42 days after balloon angioplasty
(2.8 +/- 0.7 mm2). The contribution of neointimal formation to late lumen loss
decreased over time and the contribution of late MBA loss to late lumen increased
over time and was highest at 42 days (78%). Medial necrosis was 48% at two days
after balloon angioplasty and the repopulation of the media was almost completed
at seven days. CONCLUSION: Remodeling following balloon angioplasty has an early
onset and progresses with neointimal formation to cause restenosis over the
standard 42-day time course for Yucatan micropigs. This correlates to six months
renarrowing in humans. In this model, atherosclerosis and the natural history of
restenosis, both with respect to neointimal formation and remodeling, resemble
the human disease quite closely.
PMID- 9764203
TI - Skeletal muscle myosin heavy chain expression in rats with monocrotaline-induced
cardiac hypertrophy and failure. Relation to blood flow and degree of muscle
atrophy.
AB - BACKGROUND: In congestive heart failure (CHF) the skeletal muscle of the lower
limbs develops a myopathy characterised by atrophy and shift from the slow to the
fast type fibres. The mechanisms responsible for these changes are not clear yet.
OBJECTIVES: We investigated the influence of blood flow and degree of muscle
atrophy on the myosin heavy chains (MHC) composition of the soleus and extensor
digitorum longus (EDL) of rats with right ventricle hypertrophy and failure.
METHODS: CHF was induced in 16 rats by injecting 30 mg/kg monocrotaline. Eight
animals had the same dose of monocrotaline but resulting in compensated right
ventricle hypertrophy. Two age- and diet-matched groups of control animals (nine
and five respectively) were also studied. The relative percentage of MHC1 (slow
isoform), MHC2a (fast oxidative) and MHC2b (fast glycolytic) was determined by
densitometric scan after electrophoretic separation. The relative weights of
soleus and EDL (muscle weight/body weight) were taken as an index of muscle
atrophy. Skeletal muscle blood flow was measured by injecting fluorescent
micropheres. RESULTS: CHF and Control (Con) rats showed similar degree of atrophy
both in soleus (0.40 +/- 0.06 vs. 0.44 +/- 0.06 p = NS), and EDL (0.47 +/- 0.04
vs. 0.45 +/- 0.02, p = 0.09). In CHF rats these two muscles showed a
statistically significant MHCs redistribution toward the fast type isozymes. In
fact in EDL of CHF rats MHC2a was 30.5 +/- 6.1% vs. 35.8 +/- 8.6% of the Con (p <
0.05). MHC2b was however higher (68.5 +/- 6.6% vs. 61.0 +/- 9.6%, p = 0.017). In
the soleus of CHF rats MHC1 was decreased (87.6 +/- 3.4% vs. 91.9 +/- 5.2%, p =
0.02), while MHC2a was increased (12.04 +/- 3.5% vs. 7.9 +/- 5.2%; p = 0.028).
Similar changes were not found in the muscles of the compensated hypertrophy
animals. No correlation was found between MHC pattern and the relative muscle
weight in the CHF animals. Soleus blood flow in CHF rats was significantly lower
than that of Con (0.11 +/- 0.03 ml/min/g vs. 0.22 +/- 0.03 p < 0.05), while no
differences were found in EDL (0.06 +/- 0.02 ml/min/g vs. 0.08 +/- 0.02, p = NS).
CONCLUSIONS: In rats with CHF a skeletal muscle myopathy characterised by a shift
of the MHCs toward the fast type isoforms occurs. The magnitude of the shift
correlates neither with the degree of atrophy, nor with the skeletal muscle blood
flow, suggesting that these two factors do not play a pivotal role in the
pathogenesis of the myopathy.
PMID- 9764204
TI - Alteration of intracellular Ca2(+)-handling and receptor regulation in
hypertensive cardiac hypertrophy: insights from Ren2-transgenic rats.
AB - Abnormal intracellular Ca2(+)-handling appears to be a major cause of systolic
and diastolic dysfunction in animals and humans with cardiac hypertrophy due to
pressure overload and heart failure. However, the precise mechanisms which cause
alteration of Ca2(+)-handling remain unclear. Several lines of evidence suggest
that activation of neurohormonal systems may play a central role. In particular,
widespread awareness of the importance of the renin-angiotensin system (RAS) has
occurred since experimental and clinical studies have detailed the efficacy of
angiotensin-converting enzyme inhibitors in reducing morbidity and mortality in
patients with left ventricular dysfunction. To evaluate in vivo the role of
activated RAS in the regulation of (a) cardiac receptor expression and signal
transduction mechanisms and (b) Ca2+ homeostasis, transgenic TG(mREN2)27 rats
harbouring the murine renin Ren2d gene were chosen. These animals develop
fulminant hypertension and cardiac hypertrophy at an early age despite low levels
of renin in the plasma. High expression of the transgene in the vasculature and
the heart is associated with increased local formation of angiotensin II. In the
Ren2-transgenic model alterations of beta-adrenergic neuroeffector mechanisms,
Ca2(+)-handling and alpha-adrenergic signal transduction are observed which are
very similar to those observed in the myocardium of patients with end-stage heart
failure. Moreover, treatment with specific inhibitors of the RAS, such as
angiotensin-converting enzyme inhibitors or angiotensin II-receptor antagonists,
largely reversed these defects. Studies on TG(mREN2)27 rats may provide new
insights into the pathogenesis of hypertensive heart disease and mechanisms which
promote disease progression to end-stage heart failure and also may have
important implications with regard to therapeutics of heart failure in man.
PMID- 9764205
TI - Natural co-occurrence of aflatoxins and Fusarium mycotoxins (fumonisins,
deoxynivalenol, nivalenol and zearalenone) in corn from Indonesia.
AB - Sixteen corn samples collected from Indonesia were analysed for aflatoxins (AF),
fumonisins (FM), trichothecenes and zearalenone (ZEA) using high-performance
liquid chromatography and gas chromatography-mass spectrometry. AF were detected
in 11 (69%) samples at a mean level of 119 ng/g (maximum 487 ng/g) and FM in all
of the samples at a mean level of 895 ng/g (maximum 2970 ng/g). Deoxynivalenol
(DON), nivalenol (NIV) and ZEA were each detected in two (12%) samples; 21 and 32
ng/g, 49 and 169 ng/g, and 11 and 12 ng/g, respectively. All of the AF
contaminated samples were co-contaminated with FM. Mycological study showed all
of the AF-contaminated samples were infected with A. flavus/A. parasiticus, and
the FM-contaminated samples were either infected with F. moniliforme (50%), F.
proliferatum (12%), F. nygamai (6%) or F. decemcellulare (38%). Supportive
mycological studies showed that Fusarium species isolated from Indonesian corn
were capable of producing a mean level of 10,000 micrograms/g FM. Based on these
results, the correlation between FM-producers and AF-producers on kernel
infection and contamination of these mycotoxins in corn was discussed. This is
the first report on the natural co-occurrence of AF and various Fusarium
mycotoxins, including DON and NIV in corn from Indonesia, and also the first
report on the natural occurrence of DON in corn from hot areas of Southeast Asia.
PMID- 9764206
TI - The occurrence of fumonisin B1 in maize-containing foods in The Netherlands.
AB - Seventy-eight maize-containing foods obtained from retail stores in The
Netherlands were analysed for fumonisin B1 contamination. Thirty-six per cent of
the samples were contaminated with fumonisin B1 in the range of 8 micrograms kg-1
(limit of detection) to 1430 micrograms/kg-1. Forty-six per cent of the minimally
treated maize samples (n = 39; maize for bread production, maize for popcorn,
maize flour and polenta) were contaminated with fumonisin B1 in the range of 8
380 micrograms kg-1. Twenty-six per cent of the maize-containing processed foods
(n = 39; tostada, canned maize, maize starch, maize bread, popped maize, flour
mixes, maize chips and cornflakes) were contaminated with fumonisin B1 in the
range of 8-1430 micrograms/kg-1. This survey shows that maize-containing foods in
The Netherlands frequently can be contaminated with fumonisin B1.
PMID- 9764207
TI - Fumonisin B1 in maize for food production imported in The Netherlands.
AB - Sixty-two samples of maize imported in The Netherlands and intended for human
consumption were screened for the presence and concentration of fumonisin B1.
Sixty-one of those samples contained fumonisin B1 with concentrations ranging
from 30 to 3350 micrograms kg-1, 11 maize samples contained > 1000 micrograms kg
1. The average fumonisin B1 concentration was 640 micrograms kg-1 for the
positive samples and 620 micrograms kg-1 for all samples. Medians were 600
micrograms kg-1 and 550 micrograms kg-1 for positive and all samples,
respectively. The results obtained were comparable to results from other studies
in maize from various countries.
PMID- 9764208
TI - Zeranol is formed from Fusarium spp. toxins in cattle in vivo.
AB - Zeranol, a semi-synthetic oestrogenic growth promoter, was banned in the EU in
1988. The ability of Member States to police the ban on zeranol has been hampered
by suggestions from New Zealand and from this laboratory that zeranol may be
formed by the in vivo metabolism of naturally occurring Fusarium spp. toxins. The
present study demonstrates that zeranol is formed from alpha-zearalenol and
zearalenone in vivo and is detected in bovine bile following the oral
administration of these compounds. However, it is not detected following
administration of beta-zearalenol. These data suggest that hydrogenation of alpha
zearalenol, probably in the rumen, is responsible for the appearance of zeranol.
The present study shows that environmental contamination with Fusarium spp.
toxins is widespread in Northern Ireland. Fusarium spp. toxins were present in
32% (n = 422) of all bovine bile samples tested for zeranol during 1995. Zeranol
itself was confirmed in 6.6% (n = 28) of the samples. However, the mean alpha
zearalenol and beta-zearalenol concentrations in the bile of zeranol-positive
animals were 12 and 9 times higher, respectively, than those in the zeranol
negative animals. The alpha-zearalenol concentration always exceeded the zeranol
concentration by at least 5:1. This may, in the future, permit differentiation
between zeranol abuse and natural contamination.
PMID- 9764209
TI - A collaborative study of an HPLC method for determination of ochratoxin A in
wheat using immunoaffinity column clean-up.
AB - Thirteen laboratories within the United Kingdom participated in a collaborative
study to determine ochratoxin A in wheat using an HPLC method incorporating
immunoaffinity column clean-up. Mean recovery of ochratoxin A from wheat spiked
at a level of 5 micrograms/kg was 91% for the method when using the OchraTest and
93% for the OCHRAPREP brands of column. Four samples naturally contaminated with
ochratoxin A consisting of two blind duplicates containing concentrations of
approximately 3 and 6 micrograms/kg of ochratoxin A were examined using a
specified method. The relative standard deviations obtained within laboratories
(repeatability) ranged between 9.7 and 12.5%, there being no significant
difference between the two brands of immunoaffinity column. The relative standard
deviations obtained between laboratories (reproducibility) were larger, ranging
from 24.6 to 32.1% when using the OchraTest column and 14.0 and 19.6% for the
OCHRAPREP column. When results were corrected for recovery, the apparent
difference in reproducibility between the two columns was much reduced, 14.0
17.3% for OchraTest and 10.4-17.5% for OCHRAPREP. Horrat values for
reproducibility were between 0.4 and 0.7 before correcting results for recovery
and were between 0.3 and 0.6 after correction. The performance of the
immunoaffinity column method tested compared very favourably with results of
other published collaborative studies on mycotoxins.
PMID- 9764210
TI - A highly sensitive gas chromatographic determination of levamisole in milk.
AB - An efficient extraction and sensitive gas chromatographic method is described for
the determination of the anthelminthic drug levamisole in milk. Levamisole was
extracted from alkaline milk with ethyl acetate. Clean-up of the extract was by a
series of liquid-liquid extraction steps. Levamisole residues in the extract were
determined by gas chromatography with a nitrogen-phosphorus detector. This method
was satisfactory for determining levamisole residues in milk as low as 0.5 ng/g.
Mean recoveries of 0.5-10.0 ng/g fortified milk samples ranged from 84.5 to
95.2%. Five replicate analyses performed on a milk containing incurred levamisole
residues yielded a mean of 3.34 ng/g levamisole with a CV of 3.0%.
PMID- 9764211
TI - Probenecid markedly reduces urinary excretion of ethinylestradiol and
trimethoprim slightly reduces urinary excretion of clenbuterol.
AB - This study investigated whether the illegal application of ethinylestradiol or
clenbuterol in cattle as growth promotors may be concealed by co-treatment with
drugs that affect urinary excretion. Therefore, six male veal calves were fed
with ethinylestradiol and six different male veal calves were fed with
clenbuterol for 13 days. Both groups received the growth promotors twice daily
(days -2 to 11) with milk replacer. The calves receiving ethinylestradiol were
additionally fed with probenecid on days 7-11, and the calves receiving
clenbuterol were additionally fed with trimethoprim (days 7-11). During days 1-11
of the experiment, 24-h urine and blood samples (once daily) were collected and
analyses for ethinylestradiol and clenbuterol by specific enzyme immunoassay. In
four calves the average urinary excretion of ethinylestradiol during days 7-11
(co-treatment with probenecid) was only about 25% of their average urinary
excretion of ethinylestradiol on days 1-6. In the other two calves of this group,
the excretion of ethinylestradiol was reduced to 4% on days 7-11 compared with
days 1-6. In these two calves several urine samples provided concentrations of
ethinylestradiol around the limit of detection. As a consequence, there may be a
chance of concealing ethinylestradiol application by co-treatment with
probenecid. Co-treatment with trimethoprim led only to a slight reduction of
urinary excretion of clenbuterol. The detection of clenbuterol in urine samples
from calves which were co-treated with trimethoprim can thus not be prevented.
PMID- 9764213
TI - An evaluation of the safety of Crodamol PMP.
AB - Crodamol PMP (polyoxypropylene (2) myristyl ether propionate) has been
extensively employed for many years in a wide variety of human cosmetics in the
absence of reported adverse reactions. The compound is being considered for use
as a vehicle for veterinary pharmaceuticals in food-producing animals. This paper
reviews information on the chemistry, metabolism, and toxicity of this compound,
including the details of a recently completed multi-dose study in rats. Based
upon this information, it is concluded that Crodamol PMP is a substance of
apparently low toxic potential. Potential new uses of this compound must compare
the likely exposure to the substance with the available toxicity information.
PMID- 9764212
TI - Depletion of penicillin G residues in tissues, plasma and injection sites of
market pigs injected intramuscularly with procaine penicillin G.
AB - Procaine penicillin G was administered by intramuscular (i.m.) injection to
groups of healthy 100 kg market pigs at the approved label dose (15,000 IU/kg
body weight), once daily for three consecutive days; or an extra-label dose
(66,000 IU/kg body weight), once daily for five consecutive days. Penicillin G
residue depletion was followed in plasma, tissue and injection sites using a
liquid chromatographic method. Groups of pigs were killed 1, 2, 3, 4, 5 and 8
days after the last injection with the label dose. Penicillin G was not detected
in liver after 1 day of withdrawal, in muscle and fat after 2 days of withdrawal,
in plasma after 4 days of withdrawal, in skin after 5 days of withdrawal, or in
kidney and the injection sites after 8 days of withdrawal. Other groups of pigs
were killed 1, 2, 3, 5 and 7 days after injection with the extra-label dose. In
these pigs penicillin G was not found in liver after 2 days of withdrawal, in fat
after 3 days of withdrawal, or in the muscle, skin, plasma and injection sites
after 7 days of withdrawal. Penicillin G was found at all times in the kidneys of
the groups of pigs that received the high dose. The technique used for neck
injections was critical to obtain intramuscular rather than intermuscular
injections. The Bureau of Veterinary Drugs, Health Protection Branch, Health
Canada calculated that the appropriate withdrawal period for pigs was 8 days for
a dose of 15,000 IU procaine penicillin G/kg body weight and 15 days for a dose
of 66,000 IU/kg.
PMID- 9764214
TI - Lead in wine.
AB - Elevated levels of lead in wine have been explained by several possible
contamination sources: leaded gasoline, tin-lead capsules (used to cover the
bottle neck), and brass alloys. Lead measurements from 7000 wines were used to
identify possible sources and these showed that atmospheric pollution-related
contamination (leaded gasoline) was not responsible for elevated lead
concentrations in wine. It also was shown that the presence or absence of tin
lead capsules as well as the state of tin-lead capsule corrosion had only a very
minor influence on the lead concentration in wine. The reported positive
correlation between wine age and lead concentration was confirmed by our data.
However, further statistical analysis revealed that not the age of wine but the
vintage and the wine colour were the most significant contributing factors. The
wine age itself was no longer correlated with the lead concentration after
controlling for the significant variables mentioned. The conclusions drawn agree
well with the explanation that brass is the main contamination source.
Inspections of wineries known for elevated lead levels always revealed the
presence of brass tubes and faucets. There has been a continuing and significant
reduction of lead levels in wine during the recent 7 years where measurements
were made.
PMID- 9764215
TI - Lead and cadmium in beverages consumed in Finland.
AB - The lead and cadmium contents of carbonated beverages, juices, beers and wines
were determined by ETAAS using Zeeman background correction, peak height mode and
the method of standard additions for quantitation. Other beverages were digested
in conc. HNO3, but wines were diluted with 10% HNO3. The lead contents of
beverages were negligible. The mean Pb content of juices was 9 micrograms/kg, 2
micrograms/kg in carbonated beverages, < 1 microgram/kg in mineral water and 3
and 4 micrograms/kg in domestic and imported beers. The mean lead content was 16
micrograms/l in domestic miscellaneous wines, 33 micrograms/l in imported white
wines, 9 micrograms/l in domestic red wines and 34 micrograms/l in imported red
wines. The cadmium contents in all beverages were < 1 microgram/kg, except for
domestic red wine made from raspberry, which contained 2 micrograms/l. Beverages
contribute only a negligible amount of lead and cadmium to the average Finnish
diet. However, as the total lead intake is low in Finland, about 12
micrograms/day, the share of beverages is rather high, about a fifth of the total
intake.
PMID- 9764216
TI - Analytical methods for the determination of 3-chloro-1,2-propandiol and 2-chloro
1,3-propandiol in hydrolysed vegetable protein, seasonings and food products
using gas chromatography/ion trap tandem mass spectrometry.
AB - The EC Scientific Committee for Foods and more recently the Food Advisory
Committee in the UK have proposed that levels of 3-chloro-1,2-propanediol (3
MCPD) in foods and ingredients should be reduced to the lowest possible. This
paper reports on the development of methods for the determination of parts-per
billion (microgram/kg) levels of 3-MCPD in hydrolysed vegetable protein (HVP),
flour, bread, meat and starch products using gas chromatography/ion-trap tandem
mass spectrometry (GC/ITMS/MS). Mass spectrometer conditions for detecting 3-MCPD
and the stable isotope internal standard (3-chloro-1,2-propandiol-d7) were
established. Candidate extraction methods were initially evaluated for recovery
and repeatability by spiking selected commodities at a level of 100
micrograms/kg. Extracts of ingredients and foods prepared by the candidate
extraction methods were examined by GC/ITMS/MS using samples spiked at a level of
25 micrograms/kg. The results showed that detection limits of between 3 and 5
micrograms/kg could be achieved for all commodities.
PMID- 9764217
TI - Evaluation of release of antioxidant from high density polyethylene by planar
chromatography.
AB - Irganox 1330 (1,3,5-trimethyl-2,4,5-tris(3',5'-ditert-butyl)-4'-hydroxybenzyl)-
benzene) (I), an alkylphenol compound used as antioxdiant in the production of
high density polyethylene (HDPE), was the subject of this study. The quantity of
I given up by polyethylene samples of different thickness to aqueous and
lipophilic media simulating food was studied by planar chromatography (PC). The
manner of antioxidant release was also investigated. The chromatographic method
developed was found satisfactory for the quantification of I in the migration
studies undertaken, and had quantification limits (12 ng/deposit) suitable for
quality control of HDPE.
PMID- 9764218
TI - Thermal stability of polyethylene terephthalate food contact materials: formation
of volatiles from retain samples and implications for recycling.
AB - PET packaging materials have been tested for volatile content after exposure to
high temperatures. Samples included laminates, bottles, and roasting bags, and
were heated at 120 degrees C, 150 degrees C and 230 degrees C for 50 min,
according to sample type. Volatiles released from the material were trapped on
Tenax, identified by GC-MS and assessed against a 10 micrograms/kg migration
threshold limit. Few volatiles were found for samples composed only of PET.
Volatiles from laminates varied according to the sample structure, but the main
substances identified were not related to PET, but probably came from printing
inks and adhesives. It is concluded that the migration potential of PET in high
temperature applications is very low and that the formation of volatiles during
use is unlikely to cause any special problems in polymer recovery in recycling
schemes, provided that other packaging residues are removed effectively.
PMID- 9764219
TI - Estimates of maximum limits of food colours use in Brazil through the Danish
Budget Method and the Bar and Wurtzen-modified method.
AB - The establishment of the permissible levels for the use of additives in foods
must be based on the Acceptable Daily Intake (ADI). A method that may be applied
for this purpose is the Danish Budget Method which estimates the maximum amount
of the additive that may be added to the food based on the functional properties
of the additive, and on the categories of the food in which the additive will be
used. Based on the latest information Bar and Wurtzen propose some modifications
to the original Budget Method, one of which is the addition of a correction
factor which takes into account the competition between different food additives
with the same functional properties. In the present paper, both the Budget Method
and the Bar and Wurtzen-modified method were applied to evaluate whether the
maximum levels of food colours use exceeded their ADI or not. Applying the
original Budget Method, the results showed that the colours Sunset Yellow,
Amaranth, Erythrosine, Ponceau 4R and Cochineal possibly exceeded the ADI; while
applying the modified method only the colours Erythrosine and Cochineal would
exceed the ADI. Brazilian regulatory authorities should be advised to establish
maximum limits of use for the following categories of colours: Caramel,
Inorganic, Natural and Artificial Colours Identical to the Natural Ones, where
ADIs have been evaluated by JECFA.
PMID- 9764220
TI - Sorbic acid-amine function interactions.
AB - Sorbic acid has a system of conjugated double bonds which makes it able to
undergo nucleophilic addition reactions with certain functions. The interactions
between sorbic acid and amine functions present in the endogenous constituents of
food were quantified. The formation of new products was demonstrated and the
underlying mechanisms studied using ethyl sorbate and various amines. HPLC, GC,
GC-SM and NMR analyses of the reaction mixtures enabled the products to be
isolated and identified. The addition reactions led, at 20 degrees C, to linear
monoadducts and, at 50 degrees C and 80 degrees C, to cyclic derivatives
resulting from double addition.
PMID- 9764221
TI - Evaluation of the toxicity of drug residues in food: the case for 'relay'
toxicity studies.
AB - The tissue residues of veterinary drugs given to food-producing animals are an
ill-defined mosaic of parent drug and metabolites. Consumers are only ever
exposed to this mixture in the presence of a vast excess of the excipient, food.
Given the modifying effects of food on the absorption and disposition of co
administered xenobiotics, it follows that the toxicity of these residues can only
be properly evaluated in the presence of a large excess of food. Adoption of a
relay toxicity strategy addresses these two points. The proposed relay toxicity
testing approach is as follows. The target species receives a recommended dosage
regimen of the drug, but a dose level three- to five-fold higher than normal and
the animals are then killed several days earlier than the projected withdrawal
period. The tissues from these animals, containing the residue mixture at
artificially high concentrations, are then administered to laboratory animals for
conventional toxicological evaluation. In this approach the residues do not
require individual identification and their potential toxicity is evaluated in
the presence of the inescapable excipient, food. Determination of an 'exposure'
level without observerable toxicity provides, in principle, the means of relating
human safety to a No-Observed Effect Level in laboratory animals in the
traditional manner.
PMID- 9764222
TI - The management of civilian intra-articular gunshot wounds: treatment
considerations and proposal of a classification system.
AB - The incidence of intra-articular low-velocity gunshot wounds is increasing as the
number of civilians injured by handguns grows. The severity of these injuries can
vary and the general principles of managing them, particularly in regards to the
role of irrigation, debridement and prophylactic antibiotics, are evolving. The
authors suggest that injuries can be classified according to the ultimate
location of the projectile, the level of contamination, and the type of fracture
present. Injuries in which the projectile has no contact with the synovial fluid,
with a low level of contamination, and a stable fracture pattern may be treated
non-operatively, with antibiotics only. Wounds in which the bullet remains in
contact with synovial fluid have a higher level of contamination or have a
fracture requiring internal fixation and intravenous antibiotics in combination
with more aggressive surgical treatment.
PMID- 9764223
TI - Gunshot wounds to the spine.
AB - In the USA, low velocity gunshot injuries (GSI) account for 13% of all urban
spinal injuries, and they have become the second leading cause of all spinal cord
injuries. The initial clinical evaluation should assess vascular, visceral,
and/or neurological injury. Early imaging studies are required with computerized
tomography in addition to plain radiographs to assess accurately the location and
extent of the bone injury. The role of steroids is unclear, and if given, should
be administered to GSI patients with complete or partial neurological deficit who
present within eight hours of injury. The indications for prophylactic
antibiotics have not been well established and although recommended, these are
deemed essential only in patients with associated visceral perforation. Early
surgical exploration is most appropriate to address associated vascular or
visceral injury, while spinal decompression does not appear to influence
neurological recovery. The majority of GSI spine fractures are stable;
instability is usually due to ill-advised decompression of cervical spine GSI.
Retained bullet fragments are rarely problematic; lead toxicity can occur due to
missile contact with the synovial fluid, disc space, or contact with a
pseudocyst.
PMID- 9764224
TI - Humeral fracture secondary to civilian gunshot injury.
AB - Violence is the leading cause of death in the USA. The cost of violence due to
gunshot wound is about $425 billion. While the closed fracture of the humerus is
common, humeral shaft fractures caused by gunshot wound occur infrequently. There
is much controversy regarding their management, i.e. should these injuries be
treated surgically or can they be safely treated with minimal intervention. The
aim of this study is to review our experience in the management of fourteen
patients with a humeral fracture due to gunshot wounds. Of fourteen, seven
patients were treated with local debridement, oral antibiotics and fracture
brace. The remaining seven patients underwent surgical stabilization of the
fracture. The time to union was similar in both groups (6 weeks in non-operative
to 9 weeks in open treatment). In conclusion, fracture of the humeral shaft
secondary to low velocity gunshot wound in the civilian setting can safely be
treated as a closed fracture with local wound care and oral antibiotics.
PMID- 9764225
TI - Management of civilian gunshot injuries of the femur. A review of the literature.
AB - Gunshot fractures of the femur are becoming more commonplace in modern
civilization. The initial assessment must accurately document the vascular and
neurological status of the limb as well as the characteristics of the fracture.
Low velocity gunshot wounds require a brief course of broad spectrum intravenous
prophylactic antibiotics and limited surgical debridement of the wound.
Definitive stabilization should consist of locked, reamed, intramedullary nailing
for low velocity injuries, and non-reamed nailing for high velocity injuries.
External or plate fixations are best reserved for the more severe Grade IIIC
injuries. Successful limb salvage is most dependent on the associated vascular
injury, while neurological injury is a major determinant of long-term disability.
PMID- 9764226
TI - 'Traumaphobia' disease of surgeons; can it be cured? 1996 William Gissane
Lecture.
PMID- 9764227
TI - MRI of cerebrum and cervical columna within two days after whiplash neck sprain
injury.
AB - The present study was undertaken to evaluate if MRI within 2 days of a motor
vehicle accident could reveal pathology of importance for understanding long-term
disability after whiplash neck-sprain injuries. As part of a prospective study
cervical and cerebral MRI was performed on 40 neck sprain patients with whiplash
injury after car accidents. The imaging was done within 2 days of the injury to
make sure that any neck muscle bleeding, oedema or other soft tissue injuries
could be detected. The MRI findings from the patients were both correlated to
reported symptoms 6 months after the accident and compared to a control group of
20 volunteers. The MRI of both brain and neck revealed no significant differences
between the patients and the control group. When the patients were grouped
according to the main MRI findings at intake and compared according to the
development of subjective symptoms reported by the patients, the only significant
difference was more headaches at 6 months in the groups with disk pathology or
spondylosis when compared to the group with no pathology. In conclusion, MRI
within 2 days of the whiplash neck-sprain injury could not detect pathology
connected to the injury nor predict symptom development and outcome.
PMID- 9764228
TI - Failure of femoral head fixation: a cadaveric analysis of lag screw cut-out with
the gamma locking nail and AO dynamic hip screw.
AB - The most commonly reported failure mode of sliding hip screws in published
literature is cut-out of the lag screw. This study investigates the resistance to
failure of the femoral head, with lag screws used in two types of sliding hip
screws, the gamma locking nail (Howmedica) and the dynamic hip screw (DHS)
(Synthes). The investigation consisted of biomechanical tests under static
loading conditions on 12 pairs of cadaveric femoral heads, to establish the
failure loads due to screw cut-out for the two implant lag screws. The gamma nail
appeared to reduce the tendency to cut-out in the osteoporotic bone (soft)
associated with elderly patients in whom these devices are commonly used (p <
0.05). In high density bone (hard) the gamma lag screw also appeared to be
stronger, because the DHS showed a tendency to bend. The larger diameter of the
gamma nail lag screw resists bending and appears to reduce the risk of cut-out
compared with the DHS.
PMID- 9764229
TI - Management of combined penetrating cardiac and abdominal trauma.
AB - This is a retrospective review of patients with combined penetrating cardiac and
abdominal trauma. Clinical presentation patterns are described and a management
strategy is outlined. The series comprises 25 patients. On the basis of the
mechanism of injury and the prognosis, the patients were divided into two groups:
'low risk' (single high epigastric stab wound) and 'high risk' (multiple stabs,
single or multiple gunshot wounds). There were six patients in the low-risk
group. Their intra-abdominal injuries were moderately severe. None of this group
died. There were 19 patients in the high-risk group. Three underwent emergency
room thoracotomy and died. Of the remaining patients, four underwent a
thoracotomy first for cardiac tamponade or massive haemothorax and 12 underwent a
laparotomy first because of massive haemoperitoneum. The mortality in this group
was 63 per cent. It is essential to recognize the cardiac injury in low-risk
patients; the cardiorrhaphy must be performed before the laparotomy. In high-risk
patients, the sequence of operations depends on the clinical presentation.
Obvious cardiac tamponade or massive haemothorax mandate a thoracic approach
first, while severe hypovolaemic shock with a massive haemoperitoneum justifies
the performance of a laparotomy first; a transdiaphragmatic pericardiotomy is
useful, in these cases, before proceeding to median sternotomy.
PMID- 9764230
TI - Intramural post-traumatic haematomas of the duodenum: are there any late sequelae
of operative intervention?
AB - The data of nine children with post-traumatic intramural haematoma of the
duodenum treated in Aghia Sophia Children's Hospital of Athens from 1967 to 1980
were retrospectively analysed. Diagnosis was preoperative in all but two
children, in whom diagnosis was made during laparotomy. All but one were managed
by operative intervention which consisted of simple evacuation of the haematoma
and closure of the serosal incision in two out of eight children. Six out of
eight children operated on were followed up for 15 years, during which they were
free of symptoms. Hypotonic duodenography performed in the above patients was
negative for deformity or stricture of the duodenum.
PMID- 9764231
TI - Is routine computed tomographic (CT) scanning necessary in suspected basal skull
fractures?
AB - The aim of this prospective observational study was to assess the yield of
routine fine-cut computed tomographic (CT) scans in patients with suspected basal
skull injuries. Over an 8 month period in 1994, 500 consecutive head-injured
patients were examined for clinical signs of basal skull fracture and underwent
fine-cut (5 mm) CT scans through the skull base in addition to standard (10 mm)
cuts through the vault. Clinical signs were present in 144 patients (144/500,
28.8 per cent) of which 75 (75/144, 52 per cent) had corresponding CT evidence of
fracture. A further 22 patients (22/500, 4.4 per cent) had no clinical signs but
fractures were seen on CT. The presence of cranial nerve injury, cerebrospinal
fluid leak, epistaxis, periorbital bruising, and two or more signs, were more
likely to be associated with positive CT scans (P < 0.001, chi 2 tests). The
incidence of associated mass lesions was 50.5 per cent, of which 55.1 per cent
required craniotomy. This was significantly higher than in patients without
evidence of skull base fracture (16.6 per cent) (P < 0.001, chi 2 27.165). Six
patients, two of whom had meningitis, required surgical repair of the dural
defects seen on CT. The diagnostic yield of routine fine-cut CT scans in this sub
type of head injury is 52 per cent, and is of value in detecting associated mass
lesions or significant dural defects which may require surgical intervention.
PMID- 9764232
TI - Stress fracture of the sternum: an unusual injury?
AB - Stress fracture of the sternum is a rare condition which presents as acute
anterior chest pain after repetitive upper-body exercise. Two case reports are
presented and it is postulated that this is an often underdiagnosed condition
which should be considered in the differential diagnosis of acute chest pain in
the athlete. Awareness of the injury together with meticulous clinical
examination supported by good quality radiographs or isotope bone scan may lead
to an increase in the diagnosis of this injury.
PMID- 9764233
TI - Isolated fractures of the lesser trochanter in children.
AB - In a retrospective study of 1126 children with fractures of the proximal third of
the femur, three children were found to have isolated fractures of the lesser
trochanter. This fracture occurred from a fall in one child and following
sporting activities, without a history of injury, in the others. In the latter
children, the clinical presentations were similar to those of children with
transient synovitis of the hip or Perthes disease. In each child, plain
radiographs showed an avulsion fracture of the bony portion of the lesser
trochanter. Early and complete recovery followed symptomatic treatment even when
there was marked proximal displacement of the avulsed segment of the lesser
trochanter.
PMID- 9764234
TI - Epidemiology and outcome of tibial diaphyseal fractures in footballers.
AB - A retrospective analysis of tibial diaphyseal fractures caused by football was
undertaken to establish the epidemiology and severity of these common injuries.
Analysis showed that the commonest fracture types were Tscherne C0 and C1
fractures and that only 73.9 per cent of the patients had unimpaired sporting
function after the injury. The time to return to football was significantly
related to the severity of the fracture but there was no correlation with the
skill of the player. The time to return to football for the C0 fractures averaged
7-8 months and it is therefore suggested that it is unlikely that any player will
return to football in the same season.
PMID- 9764235
TI - Aetiology of assault with respect to alcohol, unemployment and social
deprivation: a Scottish accident and emergency department case-control study.
AB - In a study to investigate the association between alcohol consumption,
unemployment and social deprivation and assault in individuals, 70 victims of
assault attending a Scottish accident and emergency department were identified
and matched with 70 paired age, sex and time of attendance controls. Seventy per
cent were male and 30 per cent female. Cases were more likely to have been
drinking (p < 0.001) and to admit to previous assault (p < 0.001), as reported in
other studies. Despite living in the same geographical area (p = 0.353), the
cases were more likely to be unemployed (p = 0.011) and had a higher mean
deprivation score (p = 0.043). These results indicate that violence is associated
with unemployment and socio-economic status of the individual and they
compliement studies based on population data which have linked rates of violence
with low income and social deprivation.
PMID- 9764236
TI - A comparison of the relative costs of cast treatment and intramedullary nailing
for tibial diaphyseal fractures in the UK.
AB - A retrospective study was undertaken to compare the costs of treating tibial
diaphyseal fractures non-operatively in a cast or operatively with locked
intramedullary nailing. In total 39 patients with isolated closed or grade I
open, two-part, displaced tibial diaphyseal fractures were studied. Of these, 18
were treated by manipulation under anaesthesia and cast immobilization, and 21 by
closed, reamed, locked intramedullary nailing. A detailed analysis of the cost of
treatment of each patient was performed and analysed in terms of the in-hospital
costs and the overall costs, taking into account time off work. The mean hospital
costs were 2226 pounds for plaster treatment and 3727 pounds for intramedullary
nailing (significantly different, p < 0.05). The mean time off work was 9 weeks
longer in the plaster group and when the cost of lost production through time off
work was added to the hospital costs, the overall costs of plaster treatment and
intramedullary nailing were 6810 Pounds and 6592 Pounds (difference not
significant). This study suggests that the cost to the hospital of treating these
fractures is less with plaster treatment but that the overall cost to the
community is no different.
PMID- 9764237
TI - An epidemic of roller-blade injuries in children.
AB - Roller blading is a new and increasingly popular leisure activity in many
countries. We reviewed 110 consecutive patients with roller-blade injuries
between 1 January and 30 June 1996. The patients ranged from 4 to 14 years in age
(mean 6.5 years). Eighty-three (75.4%) sustained injuries to the upper limb and
27 (24.5%) injured the lower limb. Fifty-six patients, were girls and 54 were
boys. Of the 110 patients, 79 (72.7%) sustained fractures, 28 (25.4%) soft tissue
injuries and 3 (2.7%) dislocations. Eighty-three (75.4%) of the patients wore no
protective equipment on the limbs. Four months following injury 103 (93.6%)
patients were fully recovered. The mean duration of school absence was 3 days.
Subsequently 101 children returned to using roller-blades following injury.
Seventy-three (66.3%) of these now use protective equipment. We found that
injuries were unrelated to age or duration of roller-blading experience or to the
brand-name of roller blades used, and that most of our patients wore no
protective equipment at the time of injury.
PMID- 9764238
TI - Methods and results of the treatment of peacetime and wartime multiple injuries-
a comparative study.
AB - Seventy-one patients suffering from multiple injuries were divided into two
groups, according to the manner in which the injuries were inflicted. Forty-one
were injured in 'peacetime' circumstances (road traffic accidents, 85.4 per
cent), and 30 patients were injured during 'military' shelling or in combat.
Since there is no generally accepted severity scoring of wartime multiple
injuries, this paper has offered one. A 'peacetime' scoring system was used to
compare the hospital mortality in the two groups. The severity of injuries in
both groups was estimated by using the Injury Severity Score. There was no
statistically significant difference between the two groups with regard to injury
severity, age, hospital mortality rate, received infusion, or the number of
specialists involved in treatment. The differences between the two groups were
significant in the application of transfusion and antibiotics, number of
operations performed, and the time span between injury and operation.
PMID- 9764239
TI - Inner city gunshot wounds.
AB - A retrospective survey was undertaken to establish the pattern and incidence of
gunshot wounds seen at a South London hospital. Forty-two gunshot wounds were
seen in 1993 and 1994. All the patients were under 39 years of age and 40 were
male. All patients had low energy transfer injuries, having been shot with hand
guns (n = 36), seven of whom had multiple bullet or shotgun wounds (n = 6).
Sixteen patients had head, neck or chest injuries, eight of whom died. Seven
patients were wounded in the abdomen or pelvis and 31 had limb injuries. Thirty
six surviving patients had a total of 33 operations and a mean hospital stay of
7.65 days (range 0-105 days).
PMID- 9764240
TI - Inferior dislocation of the patella.
PMID- 9764241
TI - Fracture dislocation of the scaphoid.
PMID- 9764242
TI - Survival following aortic transection: a case report and literature review.
PMID- 9764243
TI - Carpometacarpal dislocation producing transient motor neurapraxia of the ulnar
nerve.
PMID- 9764244
TI - Traumatic aneurysm of the ulnar artery in a child.
PMID- 9764245
TI - Dislocation of superior tibio-fibular joint in association with fracture of the
tibia: 'Monteggia' injury of the leg.
PMID- 9764246
TI - Phalangeal metaplasia following amputation in a child's finger.
PMID- 9764247
TI - Compartment syndrome of the hand--a case report.
PMID- 9764248
TI - An unusual complication of major trauma in a jockey.
PMID- 9764249
TI - A novel indication for a humeral nail.
PMID- 9764250
TI - Percutaneous drainage of a duodenal haematoma.
PMID- 9764252
TI - Two new uses of the AO wire tightener: an operative technique.
PMID- 9764251
TI - Perforation of the transverse colon as a result of minor blunt abdominal trauma.
PMID- 9764253
TI - Public health management.
PMID- 9764254
TI - Why is mortality higher in poorer areas and in more northern areas of England and
Wales?
AB - STUDY OBJECTIVE: To identify and quantify the factors responsible for the
differences in mortality between affluent and deprived areas, the north and the
south, and urban and rural areas in England and Wales. DESIGN: A multiple Poisson
regression analysis of cause specific mortality in the 403 local authority
districts, each classified by deprivation (using the Jarman Index), latitude
(from 50 degrees to 55 degrees north) and urbanisation, adjusting for age, sex,
and proportion of ethnic minorities. SETTING: England and Wales 1992. MAIN
RESULTS: All cause mortality was 15% higher in the districts comprising the most
compared with the least deprived tenth of the population, 23% higher in the most
northern (55 degrees) than in the most southern (50 degrees) districts, and 4%
higher in metropolitan (within large cities) than rural districts. Nationally
these differences were associated with 40,000, 65,000, and 15,000 excess deaths
respectively. More than two thirds of the overall excess mortality with
deprivation, latitude, and urbanisation was from three diseases--ischaemic heart
disease, lung cancer, and chronic bronchitis and emphysema. The excess mortality
from these and other diseases closely matched that predicted from differences
according to deprivation and latitude in smoking, heavy alcohol consumption,
Helicobacter pylori infection, and temperature, and thus could be attributed to
these causes. About 85% of the overall excess mortality with deprivation was
attributable to heavier smoking and 6% to heavier alcohol consumption, but diet
varied little. Deaths more directly related to deprivation (such as those caused
by H pylori infection, drug misuse, psychoses) accounted for an estimated 12% of
the excess deaths, but variation in provision and uptake of healthcare services
only 1%. The direct effects of deprivation are more strongly related to morbidity
than mortality. Of the difference in mortality with latitude, about 45% was
attributable to differences in smoking, and 25% to climate (mainly the
association of cardiovascular and respiratory disease with cold). The differences
with urbanisation were mainly because of smoking. CONCLUSIONS: Differences in the
prevalence of smoking account for much of the variation in mortality between
areas. Alcohol accounts for some, diet little. The more direct material effect of
deprivation contributes to the variation in mortality but is particularly
important with respect to differences in morbidity.
PMID- 9764255
TI - Behavioural and biological correlates of physical functioning in middle aged
office workers: the UK whitehall II study.
AB - STUDY OBJECTIVES: (1) To identify behavioural and biological correlates of poor
physical functioning and (2) to determine whether such associations are
independent of disease. DESIGN: Potential correlates were obtained from
questionnaires and screening visits at baseline and five year follow up. Physical
functioning was measured at follow up using the 10 item scale from the short-form
36 health survey. SETTING: London offices at baseline. PARTICIPANTS: 10,308 civil
servants (6895 men and 3413 women), with a median age (range) of 49 years (39-63)
at follow up. MAIN RESULTS: Multiple logistic regression showed that cigarette
smoking, physical activity, body mass index (BMI), triglycerides, fibrinogen, and
insulin were independently associated with poor physical functioning for men. For
women, physical activity, eating habits, body mass index, fibrinogen, and insulin
were independently associated with poor physical functioning. For example, among
men, current smokers who had smoked more than 20 pack years were 1.89 (95% CI
1.35 to 2.67) times as likely to have poor physical functioning as never smokers.
Men with BMI of 30 kg/m2 or more were 1.71 (95% CI 1.13 to 2.59) times as likely
to have poor physical functioning as those with BMI < 20 kg/m2. The corresponding
odds ratio for women was 2.66 (95% CI 1.80 to 3.93). With the exceptions of
fibrinogen and insulin, associations remained on exclusion of subjects with
physical disease. CONCLUSIONS: Risk factors established for physical diseases are
associated with poor physical functioning in a population of working age. These
associations may be independent of current disease.
PMID- 9764256
TI - School absence and treatment in school children with respiratory symptoms in The
Netherlands: data from the Child Health Monitoring System.
AB - STUDY OBJECTIVE: To assess the prevalence of respiratory problems, and the
relation of these problems with school attendance, medicine use, and medical
treatment. DESIGN: The Child Health Monitoring System. SETTING: Nineteen public
health services across the Netherlands. PARTICIPANTS: 5186 school children aged 4
15 years, who were eligible for a routine health assessment in the 1991/1992
school year. MAIN RESULTS: Respiratory symptoms were present in 12% of the
children. Recent symptoms suggestive of asthma (wheezing or episodes of shortness
of breath with wheezing in the past 12 months, or chronic cough, or a combination
of these) were reported for 8%. These symptoms were most frequent in the younger
children, and in children at school in towns with less than 20,000 inhabitants.
Of the children with recent symptoms suggestive of asthma, 37% reported school
absence for at least one week during the past 12 months, compared with 16% in
children without respiratory symptoms. School absence because of respiratory
illness was reported for 22%, and medicine use for respiratory problems for 38%
of the children with recent symptoms suggestive of asthma. Of these children, 21%
were receiving medical treatment, compared with 15% of the asymptomatic children.
CONCLUSIONS: Respiratory symptoms are a common health problem in children, and
they are an important cause of school absence and medicine use. However, the
percentage of children receiving medical treatment seemed quite low, indicating
that proper diagnosis and treatment are probably still a problem.
PMID- 9764257
TI - Design, objectives, and lessons from a pilot 25 year follow up re-survey of
survivors in the Whitehall study of London Civil Servants.
AB - DESIGN: To assess the feasibility of conducting a re-survey of men who are
resident in the United Kingdom 25 years after enrollment in the Whitehall study
of London Civil Servants. METHODS: A random sample of 401 study survivors
resident in three health authority areas was selected for this pilot study. They
were mailed a request to complete a self administered questionnaire, and then
asked to attend their general practice to have their blood pressure, weight, and
height measured and a blood sample collected into a supplied vacutainer, and
mailed to a central laboratory. Using a 2 x 2 factorial design, the impact of
including additional questions on income and of an informant questionnaire on
cognitive function was assessed. RESULTS: Accurate addresses were obtained from
the health authorities for 96% of the sample. Questionnaires were received from
73% and blood samples from 61% of the sample. Questions on income had no adverse
effect on the response rate, but inclusion of the informant questionnaire did.
Between 1970 and 1995 there were substantial changes within men in the mean blood
pressure and blood total cholesterol recorded, as reflected by correlation
coefficients between 1970 and 1995 values of 0.26, and 0.30 for systolic and
diastolic blood pressure and 0.38 for total cholesterol. CONCLUSION: This pilot
study demonstrated the feasibility of conducting a re-survey using postal
questionnaires and mailed whole blood samples. The magnitude of change in blood
pressure and blood total cholesterol concentrations within individuals was
greater than anticipated, suggesting that such remeasurements may be required at
different intervals in prospective studies to help interpret risks associations
properly. These issues will be considered in a re-survey of the remaining
survivors of the Whitehall study.
PMID- 9764258
TI - Health care expenditures after introduction of a gatekeeper and a global budget
in a Swiss health insurance plan.
AB - STUDY OBJECTIVES: To assess whether the introduction of "managed care" (capitated
budget and utilisation control by general practitioners) in a Swiss health
insurance plan caused a selective disenrolment of plan members, and whether it
achieved its goal of reducing health care expenditures. DESIGN: Controlled before
after analysis of health insurance claims. SETTING: Health insurance plan of the
University of Geneva, Switzerland, which introduced managed care at the end of
1992, and comparison plan, which reimbursed health care expenditures without
setting a budget or controlling access. PARTICIPANTS: Analysis of self selection:
university plan members who accepted (3993) or refused (659) transfer to managed
care. Analysis of change in expenditures: cohorts of persons continuously
enrolled in the university (1575) and comparison (3384) plans in 1992 and 1993.
MAIN RESULTS: During 1992, the year before the transformation of the university
plan, persons who refused managed care had generated 35% higher expenditures than
those who accepted managed care (p < 0.001). Between 1992 and 1993, expenditures
per member decreased by 9% in the university cohort and increased by 11% in the
comparison cohort (p = 0.004). Technical procedures (laboratory tests, physical
therapy, drugs) decreased most in the university plan. No impact on hospital
admissions was detected. CONCLUSIONS: Introduction of gatekeeping and budget
management by physicians caused a favourable self selection process for the
university plan. In addition, the managed care plan achieved a substantial
decrease in overall health care expenditures in its first year of operation,
chiefly by reducing outlays for technical procedures.
PMID- 9764259
TI - The feasibility of creating a checklist for the assessment of the methodological
quality both of randomised and non-randomised studies of health care
interventions.
AB - OBJECTIVE: To test the feasibility of creating a valid and reliable checklist
with the following features: appropriate for assessing both randomised and non
randomised studies; provision of both an overall score for study quality and a
profile of scores not only for the quality of reporting, internal validity (bias
and confounding) and power, but also for external validity. DESIGN: A pilot
version was first developed, based on epidemiological principles, reviews, and
existing checklists for randomised studies. Face and content validity were
assessed by three experienced reviewers and reliability was determined using two
raters assessing 10 randomised and 10 non-randomised studies. Using different
raters, the checklist was revised and tested for internal consistency (Kuder
Richardson 20), test-retest and inter-rater reliability (Spearman correlation
coefficient and sign rank test; kappa statistics), criterion validity, and
respondent burden. MAIN RESULTS: The performance of the checklist improved
considerably after revision of a pilot version. The Quality Index had high
internal consistency (KR-20: 0.89) as did the subscales apart from external
validity (KR-20: 0.54). Test-retest (r 0.88) and inter-rater (r 0.75) reliability
of the Quality Index were good. Reliability of the subscales varied from good
(bias) to poor (external validity). The Quality Index correlated highly with an
existing, established instrument for assessing randomised studies (r 0.90). There
was little difference between its performance with non-randomised and with
randomised studies. Raters took about 20 minutes to assess each paper (range 10
to 45 minutes). CONCLUSIONS: This study has shown that it is feasible to develop
a checklist that can be used to assess the methodological quality not only of
randomised controlled trials but also non-randomised studies. It has also shown
that it is possible to produce a checklist that provides a profile of the paper,
alerting reviewers to its particular methodological strengths and weaknesses.
Further work is required to improve the checklist and the training of raters in
the assessment of external validity.
PMID- 9764260
TI - Maternal and infant health problems after normal childbirth: a randomised
controlled study in Zambia.
AB - STUDY OBJECTIVES: The main aim of the study was to discover if a midwife home
visiting programme has a significant effect on the prevalence of health problems
and breast feeding behaviour of mothers who delivered normally and their healthy
fullterm newborn babies, during a period of 42 days after delivery. Another aim
was to compare the mothers', the midwife's, and the doctor's findings of
prevalence of health problems at the end of the puerperium period. DESIGN: A
randomised controlled trial was carried out. One group of mothers and their
infants were randomly allocated to a home visiting group (Group A); the other
group (Group B) was only visited at day 42. SETTING: The study was carried out at
the University Teaching Hospital (UTH) in Lusaka, the capital city of Zambia.
PARTICIPANTS: A total of 408 mothers who had a normal delivery and gave birth to
a healthy fullterm infant, as assessed by the attending midwife, were randomised
to two groups. Group A consisted of 208 mother/infant dyads who were visited by a
midwife in their homes at days 3, 7, 28, and 42 after delivery and Group B
consisted of 200 mother/infant dyads who were only visited at day 42. MAIN
RESULTS: At day 42 an equal proportion (30%) of mothers in both groups perceived
that they had health problems. The prevalence of infant health problems in Group
B was significantly higher (p < 0.01) as perceived by mothers. There were more
mothers in Group B (p < 0.01) perceiving insufficient milk production and giving
supplementary feeding. At day 42, mothers in Group A (56%) took more actions than
mothers in Group B (41%) to solve infant health problems (p < 0.03). In both
groups the mothers' perceived own health problems, were significantly higher (p <
0.01) than those observed by the obstetrician and those observed by the midwife.
The midwife found more infant health problems in Group B (p < 0.01) than in Group
A and more infants with health problems in both groups compared with the
paediatrician's findings (p < 0.01). CONCLUSIONS: There was a significant
difference between the mothers' reported health problems and the health problems
identified by the midwife and the doctors. The study shows that a midwife home
visit and individual health education to mothers, reduce the prevalence of infant
health problems, and enables the mother to more often take action when an infant
health problem is identified. There is a need to re-evaluate the midwifery
training curriculums with the intention to include more infant management care.
PMID- 9764261
TI - Major incidents in Britain over the past 28 years: the case for the centralised
reporting of major incidents.
AB - STUDY OBJECTIVES: To describe the incidence and epidemiology of major incidents
occurring in Britain over the past 28 years. METHODS: Major incidents were
identified through a MEDLINE search, a hand search of journals and government
reports at the Home Office Emergency Planning College, newspaper reports, a
postal survey of ambulance emergency planning officers, and through requests for
information posted on the internet. MAIN RESULTS: Brief incidents profiles from
108 British major incidents are presented. Most major incidents pass unreported
in the medical literature. On average three to four major incidents occur in
Britain each year (range 0-11). Sixty three of 108 (59.2%) of incidents involve
public transportation. The next two largest groups are civil disturbance 22 of
108 (20.3%) and industrial accidents 16 of 108 (14.8%). Although incidents at
sports stadiums are rare they produce large numbers of casualties. The data
currently available on major incidents are difficult to find and of questionable
accuracy. CONCLUSIONS: The lack of data makes planning for major incidents and
exercising major incident plans difficult. Casualty incident profiles (CIPs) may
assist major incidents exercises and planning. CIPs from future major incidents
should be collated and made available to all major incident planners.
PMID- 9764262
TI - Individual social class, area-based deprivation, cardiovascular disease risk
factors, and mortality: the Renfrew and Paisley Study.
AB - OBJECTIVE: To investigate the associations of individual and area-based
socioeconomic indicators with cardiovascular disease risk factors and mortality.
DESIGN: Prospective study. SETTING: The towns of Renfrew and Paisley in the west
of Scotland. PARTICIPANTS: 6961 men and 7991 women included in a population-based
cardiovascular disease screening study between 1972 and 1976. MAIN OUTCOME
MEASURES: Cardiovascular disease risk factors and cardiorespiratory morbidity at
the time of screening: 15 year mortality from all causes and cardiovascular
disease. RESULTS: Both the area-based deprivation indicator and individual social
class were associated with generally less favourable profiles of cardiovascular
disease risk factors at the time of the baseline screening examinations. The
exception was plasma cholesterol concentration, which was lower for men and women
in manual social class groups. Independent contributions of area-based
deprivation and individual social class were generally seen with respect to risk
factors and morbidity. All cause and cardiovascular disease mortality rates were
both inversely associated with socioeconomic position whether indexed by area
based deprivation or social class. The area-based and individual socioeconomic
indicators made independent contributions to mortality risk. CONCLUSIONS:
Individually assigned and area-based socioeconomic indicators make independent
contributions to several important health outcomes. The degree of inequalities in
health that exist will not be demonstrated in studies using only one category of
indicator. Similarly, adjustment for confounding by socioeconomic position in
aetiological epidemiological studies will be inadequate if only one level of
indicator is used. Policies aimed at reducing socioeconomic differentials in
health should pay attention to the characteristics of the areas in which people
live as well as the characteristics of the people who live in these areas.
PMID- 9764263
TI - Participation of French general practitioners in public health surveillance: a
multidisciplinary approach.
AB - STUDY OBJECTIVES: To evaluate the feasibility of a novel approach to measure
compliance of sentinel general practitioners (SGPs) in sentinel public health
surveillance and to determine the characteristics in the SGP's profile that can
be objectively associated with their perseverance in public health surveillance.
DESIGN: Prospective study of the compliance of the SGPs (compliance being defined
as the length of time during which an SGP complies with a given theoretical
surveillance protocol) and qualitative study of the determinants of their initial
motivations (using group and face to face interviews). SETTING: The 1970 SGPs who
have participated in the Sentinel system since 1984. PARTICIPANTS: Among them,
the 502 SGPs recruited since 1 July 1992 have been questioned by mailed
questionnaire and 20 SGPs have been questioned during face to face semistructured
interviews. MAIN RESULTS: According to the maximum number of silences allowed by
the given theoretical protocol, median compliances varied between 1.9 months (95%
CI = (1.8, 2.0)) and 14.3 months (95% CI = (13.8, 15.2)). In multivariate
analysis, long compliances for SGPs with a < or = 5 or > or = 20 years seniority
was seen and an interest in using multimedia home servers. On the other hand,
interest in local epidemiological surveys and previous experience with other
surveillance networks or clinical trials were associated with short compliances.
No statistical association was found between compliance and computing experience,
having a medical secretary, a particular feeling of being a "public health
actor", or the desire to belong to a GPs' network. A thematic analysis of
interview records showed that the main motivation of the SGPs was their need to
share their experiences and to self evaluate by comparison with colleagues by the
means of a surveillance system that would be used as a health information system.
CONCLUSIONS: The longitudinal method used in this study was shown to be an
efficient tool to monitor non-compliant SGPs with respect to given surveillance
protocols. Furthermore, this approach allows the selection out of the SGPs'
profile the characteristics that are associated with a longer compliance. The
additional variables to be taken into account in this profile could be identified
among the topics, attitudes, and experiences collected during the semistructured
interviews. This work considers the question of understanding what determines the
motivation of GPs to participate in public health surveillance and what are their
expectations of feed back. This question is essential if information systems in
general practice are to be implemented.
PMID- 9764264
TI - Control group characteristics and study outcomes: empirical data from a study on
mortality of patients with type 2 diabetes mellitus in Dutch general practice.
AB - STUDY OBJECTIVE: Control group characteristics as comorbidity and chronic
psychosocial problems may play an important part in study outcomes. A primary
care data base was used to quantify the effects of varying the case mix of
participants. DESIGN: Historical cohort study. SETTING: Data were collected from
1967-1996 in four Dutch general practices performing the Continuous Morbidity
Registration Nijmegen. PATIENTS AND CONTROLS: All newly diagnosed type 2 diabetic
patients in the period 1967-1989 fulfilling the WHO criteria (n = 265); for each
type 2 diabetic patient a control was matched for practice, sex, age, and social
class; from these controls subgroups were selected based on the absence of
different types of morbidity; these subgroups were also matched for practice,
sex, age, and social class. MAIN RESULTS: The relative risk of mortality in type
2 diabetic patients in comparison with various subsets of controls ranged from
1.33 (95% CI 0.97, 1.81) to 2.16 (95% CI 1.46, 3.20). CONCLUSION: Control group
characteristics as comorbidity and chronic psychosocial problems turned out to
influence the risk estimation in a cohort study. General practice data enhance
the study of these aspects.
PMID- 9764265
TI - Approaches to the denominator in practice-based epidemiology: a critical
overview.
AB - OBJECTIVES: An accurate knowledge of the population at risk is a fundamental
requirement for determining rates and making comparisons in epidemiological
research. The major obstacle of studying the epidemiology of sentinel practice
networks is the determination of population at risk, in this case, the reference
population of medical practices. This article is intended to give a brief
overview of major denominator approaches used in practice based epidemiology
today, to discuss their underlying assumptions, their strengths and limitations.
DESIGN: The literature used in this paper was searched from Medline databases of
1970-1997 using the logical expression "denominator and practice". More
literature was identified from the references cited in those articles and from
research reports that were available to the authors. MAIN RESULTS: There are
various approaches to the denominator at different levels of complexity, which
were presented akin to the well known "iceberg phenomenon": with only a small
portion of the iceberg visible above the surface, inference as to the size of the
invisible part may still be made under certain assumptions. Crude numbers of
cases may still reflect trends in the true epidemiology of disease and may be
useful for time-series analyses. Differences in the number of network
participants over time and across region may be controlled for by using the
number of sentinel practices as a denominator. The number of consultations is a
first step towards a population-based denominator, reflecting characteristics of
both patients and the network. The yearly or quarterly contact group is a true
person-based denominator, yet disregarding the population not consulting. The
population in practices' catchment areas can be either determined from patient
lists or estimated using mathematical models. The ideal denominator is the total
population in a geographically defined area, though this information can be
directly related to medical practices only in very few countries. CONCLUSIONS:
Although a person, or ideally a population-based denominator is desirable, even
"lower-level" denominators may be suitable for certain research topics. In
countries without patient registration, the estimation of incidences and
prevalences has many methodological uncertainties that limit the use of sentinel
practice systems. Assuming representativeness, valid analytical or time-series
studies, however, can still be carried out even if there is very little
information on the population at risk covered by particular medical practices.
PMID- 9764266
TI - Audit of populations in general practice: the creation of a national resource for
the study of morbidity in Scottish general practice.
AB - STUDY OBJECTIVE: To create a national data resource for studying morbidity in
Scottish general practice, complementary to existing information systems and
available for management and research purposes at national and local levels.
DESIGN: The Department of General Practice, University of Aberdeen has worked
since 1988 to collect and analyse computerised information at practice, regional,
and national levels by distribution of a floppy disk-based software program,
which extracts a predetermined dataset from each general practice computer
system. SETTING: Almost 100% of patients in Scotland are registered with a
general practitioner. Scotland has a national computer system, General Practice
Administration System for Scotland (GPASS), used by over 75% of all Scottish
practices. Escalating costs of health care and demographic changes in the
national population emphasise the monetary value of the gatekeeper role of
general medical practice. General practitioners' increasing involvement in the
provision and purchasing of care has raised the importance of the management of
populations as well as the care of individual patients. PATIENTS: Collection of
major morbidity and prescribing data from up to 2.4 million patients,
approximately half the population of Scotland, takes place biannually. A subset
of practices (population 282,700 patients; 52 practices) are continuously
collecting doctor/patient contact information (symptoms or diagnoses). MAIN
RESULTS: The data collected provide information at the level of the individual
patient. Morbidity, prescribing, screening, and administrative data can be linked
by patient, date or postcode. The sample population studied is representative by
age, sex, deprivation, and sparsity (using the postcode) of the national
population. Large sub-populations of patients satisfying a selected criteria can
be extracted for further study of needs assessment or of epidemiological
research. CONCLUSIONS: The gatekeeping role of Scottish general practice and the
predominance of GPASS favours standardisation of methods of data capture and the
construction of large regional, national, and Continuous Morbidity databases.
Analysis by geographical, demographic, and temporal distributions allows the
changing patterns of illness and provision of health care to be studied in
substantial detail to the benefit of patients, doctors, and the national health
service.
PMID- 9764267
TI - Anonymous unlinked testing as a sentinel approach: experience in Germany.
AB - STUDY OBJECTIVE: To establish a laboratory sentinel as a supplementary instrument
for monitoring the seroprevalence of HIV among childbearing women as a proxy to
the heterosexually active population. DESIGN/SETTING: Anonymous unlinked testing
of neonatal dried blood spots has been performed in central laboratories of three
federal states since 1993. The survey uses residual dried blood spots collected
on Guthrie cards for screening of infants for metabolic disorders. These are
eluted and tested for HIV antibodies. Data retained with the specimen are only
district of residence along with year and month of birth. PARTICIPANTS: Because
maternal IgG crosses the placenta before birth, the presence of antibodies in
newborns reflects the infection status of the mother. Childbearing women are
fairly representative for the heterosexually active general population. MAIN
RESULTS: The observed HIV prevalence in childbearing women of less than 1 per
thousand confirms the assumption of a low rate of HIV infection in the general
population. Significant time trends could not be detected, but HIV prevalence was
higher in metropolitan compared with rural areas. CONCLUSIONS: Laboratory
sentinels in general and the anonymous unlinked testing of neonatal dried blood
spots in particular can supply additional information on HIV seroprevalence. This
surveillance system could be expanded to utilise residual samples of other
sources as well as to monitor the immunity against specific vaccine preventable
diseases and other infectious diseases of public health relevance.
PMID- 9764268
TI - Surveillance of influenza in Wales: interpreting sentinel general practice rates
using contemporaneous laboratory data. Opportunities and limitations.
AB - OBJECTIVES: To evaluate the opportunities and limitations of using laboratory
data to enhance sentinel general practice surveillance of influenza. DESIGN:
Descriptive study of active sentinel surveillance of clinically diagnosed
influenza in general practice and passive total population surveillance of
laboratory reports of influenza A, influenza B, Mycoplasma pneumoniae, and
respiratory syncitial virus infections. SETTING: Wales. SUBJECTS: Total sentinel
practices population (currently 228,130); population of Wales (2,913,000, 1994
mid-year estimate). MAIN OUTCOME MEASURES: Simplicity, flexibility,
acceptability, sensitivity, predictive value positive, representativeness, and
timeliness of a surveillance system. Rate of influenza and other respiratory
infections. RESULTS: Sentinel general practice surveillance of influenza in Wales
is simple, flexible, acceptable, timely, representative, and relatively
sensitive. Current laboratory surveillance is complex and less timely than
sentinel practice surveillance but is complete and has a relatively high positive
predictive value. For the period January 1993 to September 1996, peaks in rates
of influenza reported by sentinel practices during winters 1993/94 and 1995/96
were temporally associated with increased rates of laboratory confirmed influenza
A and respiratory syncitial virus, whereas the peak in 1994/95 was associated
with increased rates of laboratory confirmed influenza B, M pneumoniae, and
respiratory syncitial virus. CONCLUSIONS: Timely laboratory data can add value to
influenza data already obtained from sentinel general practice surveillance.
However continuous audit is essential to resolve the possible limitations of
either surveillance system.
PMID- 9764270
TI - Programme for the surveillance of influenza in Portugal: results of the period
1990-1996.
AB - OBJECTIVES: To describe the situation of the influenza in Portugal through the
estimates of the incidence rates and the identification of the viral strains
implicated on it during the period 1990-1996. DESIGN: The integrated clinical and
laboratory surveillance system for influenza in Portugal is based on the
Portuguese sentinel network. Influenza cases are identified by general
practitioners (GP) and notified to Division of Epidemiology (DEP) and to National
Influenza Centre. Clinical and epidemiological data based on the clinical
diagnosis are recorded and incidence rates are computed for the whole country.
Throat swabs and blood samples are taken from the patients with influenza and
sent to the National Influenza Centre to identify and classify the viral strains
implicated. PARTICIPANTS: Lists of patients of the GPs collaborating on "Medicos
Sentinela" network. RESULTS: In 1990-1991, 1992-1993, and 1994-1995 there was a
higher prevalence of influenza B virus and the highest influenza activity
occurred in February and March in contrast with 1991-1992, 1993-1994, and 1995
1996 where the highest numbers of influenza cases occurred in November and
December, and were associated with influenza A. CONCLUSIONS: During the past six
years, 1990-1996, the influenza activity has been moderate in Portugal. From 1990
1996 influenza A and B viruses were prevalent every second year. The prevalence
of influenza A was associated with the occurrence of the highest number of
influenza cases during December and January and the prevalence of influenza B
with the occurrence of the highest number of influenza cases during February and
March.
PMID- 9764269
TI - Surveillance of influenza-like illness in France. The example of the 1995/1996
epidemic.
AB - STUDY OBJECTIVES: To discover if continuous computerised collection of morbidity
data through a medical practice based sentinel network can be used to monitor
influenza-like illness (ILI) epidemics. To obtain rough estimates of influenza
vaccine effectiveness. DESIGN: Continuous passive surveillance of ILI through a
computerised network of voluntary sentinel general practitioners (SGPs) in France
(Sentinelle system). SETTING: Five hundred SGPs practices. PARTICIPANTS: Since
1984, SGPs updated a database with information on eight communicable diseases
including ILI, via videotext terminals. Each ILI case is defined by the
association of a sudden fever of 39 degrees C or above, respiratory symptoms, and
myalgias. An ILI epidemic is detected when the national weekly incidence rate
exceeds a seasonal threshold for two successive weeks. MAIN RESULTS: An ILI
epidemic was reported from November 1995 to January 1996. In total, 13,951
individual cases were reported by SGPs during the epidemic period. The size of
the epidemic (number of patients consulting a GP) was estimated to be 2,370,000
subjects. Maps of the epidemic showed that all regions have reported a high level
ILI activity. The attack rate was the highest in school age children (13.5/100)
and decreased as the age rose. Nearly 6% of the reported ILI cases among adults
and elderly were vaccinated. The flu vaccine effectiveness against ILI was
estimated to be 66% (95% CI 73%, 92%), ranging between 83% (95% CI 73%, 92%)
among the subjects aged 15 to 24 years old to 16% (95% CI -12%, 44%) among the
subjects aged 75 years or older. CONCLUSIONS: The Sentinelle system demonstrated
adequate sensitivity and timeliness regarding ILI epidemic. Moreover, results of
the monitoring were made available on the internet to increase the dissemination
of information. Also, estimates of influenza vaccine effectiveness have been
easily obtained. Altogether, they represent key points for the control of crisis
situation such as ILI epidemics or pandemics.
PMID- 9764271
TI - A study of reasons for an increase in acute respiratory tract infections reported
by influenza sentinel practices in Germany.
AB - The influenza sentinel and early warning system of the working group on influenza
(AGI) comprises more than 600 general practitioners and paediatricians
nationwide. The observations made by national influenza monitoring systems rely
on parameters that differ between countries. The definition of the numerators and
denominators used depends to an important extent on the national health care
systems, and considerable differences between the national monitoring systems
have to be expected. Consequently the validity and reliability of recorded data
as well as the indicative value of certain observations have to be checked for
each system. The reasons for an increase in acute respiratory infections relative
to total practice contacts, as well as the number of persons who are unable to
work, were investigated by telephone interviews with the reporting physicians.
Reasons for such increases given by the physician included increases in morbidity
in the population but to a considerable extent "organisational" reasons, not
linked to an increase in morbidity were identified. Many of those
"organisational" reasons seemed to be relevant in health care systems that allow
the patients a free choice of the contacted physician. The telephone interview
was helpful for interpretation of the data and the detection of primary local
outbreaks.
PMID- 9764272
TI - Epidemiology of chickenpox in France (1991-1995).
AB - STUDY OBJECTIVES: To decide whether a mass immunisation against chickenpox should
be or should not be organised, it is important to have up to date data on the
disease and to have baseline data to further assess a mass immunisation strategy,
if any. DESIGN: Recent chickenpox epidemiology (age and sex distribution,
seasonal dynamic and complications) in France are reviewed. SETTING: The system
works with about 500 Sentinelle general practitioners (SGPs) and has provided
surveillance of frequent communicable diseases in continental France since 1984.
PARTICIPANTS: The data were collected by the computerised Sentinelle system. The
Sentinelle system uses a videotex server that allows information exchange, data
entry, and synthetic return of information. Chickenpox was defined as a sudden
onset of typical skin eruption with pruritus, leaving scabs and associated with
moderate fever. For each reported case, the SGP gave information on the age of
the patient, sex, prevailing childcare for the children, contacts and
complications (skin superinfections, lower and upper respiratory infections,
conjunctivitis and corneal infections, nervous system injuries, stomatitis and
others). Spectral analysis was used to detect cyclical patterns. MAIN RESULTS:
Between 1991 and 1995, 15,817 cases of chickenpox were reported and provided the
basis for the analysis. The yearly national incidence was 1.0-1.35 cases per 100
inhabitants. A pronounced annual periodicity of the incidence was observed and
confirmed by spectral analysis. Ninety two per cent of chickenpox cases occurred
in children under 14 years of age with about 5% being under one. Complications
were reported in 2% of the cases. Common complications reported were skin
superinfections, lower and upper respiratory tract infections. However, 21 cases
out of 318 complications were nervous system injuries including six encephalitis
or cerebellar ataxia. All these cases recovered completely. CONCLUSIONS:
Chickenpox is usually a benign childhood disease. This study affords up to date
observations on the disease in France. A large panel of complications has been
reported. This paper provides the first attempt to describe the epidemiology of
chickenpox in France.
PMID- 9764273
TI - Contamination of human breast milk with organochlorine residues: a comparison
between East and West Germany through sentinel practice networks.
AB - STUDY OBJECTIVE: The aim of the study was to assess and compare the contamination
of human breast milk with organochlorine residues through two sentinel practice
networks in Lower Saxony, a state of former West Germany, and Saxony-Anhalt, a
state of former East Germany. DESIGN: Eligible women were enrolled in this cross
sectional study by a network of 51 paediatric practices in Lower Saxony and 44 in
Saxony-Anhalt when bringing their babies for a regular screening examination four
to six weeks after delivery. Sociodemographic, lifestyle, and exposure factors
were determined by questionnaire. Milk samples were analysed for
hexachlorocyclohexane (HCH), hexachlorbenzole (HCB), DDT, dieldrin,
polychlorinated biphenyls (PCB), and heptachlorepoxid (HCE); half the samples
were also analysed for dioxin. Analytic statistics were computed using multiple
logistic regression. SETTING: The study was conducted in Lower Saxony, Germany,
from July 1992 to June 1993, and in Saxony-Anhalt, Germany, from January to June
1995. PARTICIPANTS: 156 primiparous, breast-feeding women from Lower Saxony and
113 from Saxony-Anhalt were studied, who either were born and raised in former
West or East Germany, respectively. MAIN RESULT: Mean age of mothers and children
differed significantly between the two study groups. In Lower Saxony all but two
milk samples were well below the tolerable concentrations established by the
German Research Council (Deutsche Forschungsgemeinschaft (DFG)). In Saxony-Anhalt
no participant had concentrations above those recommended by the DFG. After
adjustment for age of mother and child, occupational and non-occupational
pesticide contact, DDT and beta-HCH concentrations were significantly lower in
Lower Saxony; HCE and dieldrin concentrations were lower in Saxony-Anhalt. No
differences between the two states were found for PCB, HCB, gamma-HCH, and
dioxin. CONCLUSIONS: Breast milk contamination levels in former East German
Saxony-Anhalt exceeded the contamination in Lower Saxony only for DDT and beta
HCH.
PMID- 9764275
TI - Public health: where should we be in 10 years?
PMID- 9764274
TI - Sentinel practices in evaluating longer periods of care: quality of life and drug
therapy of terminally ill persons in Lower Saxony (Germany).
AB - STUDY OBJECTIVES: (1) To study the feasibility of using sentinel practice
networks to evaluate longer periods of care. (2) To assess the quality of life
and drug therapy of community dwelling terminally ill persons. DESIGN:
Prospective longitudinal design with GPs in an existing sentinel practice network
identifying "terminally ill" persons and recording the following data: age, sex,
diagnoses, and ongoing drug therapy initially, time, place, duration, services,
and drug changes for every contact, quality of life (HRCA-QL Index, Spitzer
Index, uniscale), pain intensity and frequency on a weekly basis, and time and
circumstances of death. SETTING: 26 GP practices in Lower Saxony, Germany.
PATIENTS: 47 patients (age: mean 76 years, range 31 to 98; sex: 21 male, 26
female; diagnosis: 35 with cancer) with 582 contacts. Mean of recorded time
before death was 70 days (median 50). MAIN RESULTS: Average number of physician
patient contacts increased from 0.7 a week three months before death to 2.4 in
the final week. Quality of life decreased during that period (HRCA-QL Index: 5.1
to 0.8; Spitzer: 4.4 to 0.8; uniscale: 37 to 9). In the last week of life, no
person was free of pain; analgetic therapy was "successful" in 57% of cases.
CONCLUSIONS: (1) The sentinel practice approach is feasible for evaluating longer
periods of care. The generalisibility, however, may be limited to certain
subgroups. (2) The observed trends in quality of life, pain, and analgetic
treatment should be compared with those in other settings and countries to
identify the scope of care improvement.
PMID- 9764276
TI - An excess of tetralogy of Fallot in Malta.
AB - STUDY OBJECTIVE: To estimate birth prevalence of tetralogy of Fallot (TF) in
Malta. DESIGN: Retrospective data collection and analysis, and comparison with
earlier epidemiological studies dealing with congenital heart disease. SETTING:
Regional hospital providing exclusive diagnostic and follow up services for the
entire country of Malta. PATIENTS: All Maltese live births diagnosed as having
TF. MAIN RESULTS: The birth prevalence of TF in Malta for the period 1980-1994
was 0.64/1000 live births (95% confidence intervals 0.48, 0.85/1000 live births).
This was significantly higher than previously reported in the medical literature.
CONCLUSIONS: The Maltese gene pool seems to have a genetic predisposition towards
live births with TF. Population genetic studies with emphasis on the prevalence
of 22q11 microdeletion may yield clues regarding the cause of the high rate of
this condition.
PMID- 9764277
TI - Relation between locomotion impairment, functional independence in retirement,
and occupational strain resulting from work carried out during working life.
Study of a sample population of 350 miners in the Loire valley in France.
AB - STUDY OBJECTIVES: To analyse long term effects of working conditions experienced
at an advanced age, and after retirement by quantifying occupational strain,
impairment, and disability to establish their interrelation. DESIGN:
Retrospective study. PARTICIPANTS: Retired miners from The French Coal Board who
had worked in the coal fields of the Loire valley. From a potential population of
507 retired miners, 350 were completely evaluated. MEASUREMENT: The study
examines the occupational strain experienced by each subject, measured using both
auto-evaluation and evaluation by experts and the locomotion impairment and the
functional independence. MAIN RESULTS: A significant relation between the
evaluation of occupational strain and functional independence and locomotion
impairment of the low back was found and also a significant relation between
locomotion impairment of the low back and the length of time spent working at the
coal face. CONCLUSIONS: This study confirms other studies as regards the effects
of occupation on health status and on the aging process, but it goes further to
show the consequences of this relation on functional independence.
PMID- 9764278
TI - Underregistration of neonatal deaths: an empirical study of the accuracy of
infantile vital statistics in Taiwan.
AB - STUDY OBJECTIVE: The accuracy of the official statistic on infant deaths in
Taiwan has been questioned. This study aimed to survey infant deaths nationwide,
to measure associated vital statistics, and compare them with the official
statistics to assess accuracy. DESIGN AND PARTICIPANTS: A nationwide survey of
all gestational outcomes occurring at > or = 20 weeks' gestation over a three day
study period (15-17 May 1989) was conducted to collect data from 23 counties and
cities nationwide using a two stage data collection procedure. MAIN RESULTS: The
survey derived infant death rate was 9.72 per 1000 live births, which was higher
than the reported official statistic of 5.71 per 1000 live births. A more
detailed examination of data on infant deaths showed that the estimated neonatal
death rate of 6.68 per 1000 live births (95% confidence intervals: 3.33, 11.96
per 1000 live births) was significantly higher than the published official
statistic of 1.94 per 1000 live births, while the postneonatal mortality of 3.04
per 1000 live births was comparable to the reported statistic of 3.37 per 1000
live births. CONCLUSIONS: This study empirically documented the underregistration
of infant deaths in Taiwan, particularly those occurring during the first 27 days
of life.
PMID- 9764279
TI - Socio-cultural factors in maternal morbidity and mortality: a study of a semi
urban community in southern Nigeria.
AB - STUDY OBJECTIVE: To understand community based or socio-cultural factors that
determine maternal morbidity and mortality in a semi-urban setting. DESIGN: The
study is an exploratory multidisciplinary operations research and the instruments
were focus groups and interviews. SETTING: Ekpoma, a semi-urban community with a
population of 70,000 in central part of Edo state in southern Nigeria.
PARTICIPANTS: Thirteen groups of women, two groups of men, and two groups of
traditional birth attendants. RESULTS: There is a fairly good knowledge of
haemorrhage but this is circumscibed by attitudes, practices, and situations that
keep women away from or delay the decision to seek modern obstetric care.
CONCLUSIONS: For a fuller understanding of maternal morbidity and mortality, it
is important to consider factors outside the hospital and formal medical
practice. Furthermore, a change of existing knowledge, attitudes, practices, and
situations can be enhanced through modelling on them.
PMID- 9764280
TI - Reported health, lifestyles, and use of health care of first generation
immigrants in The Netherlands: do socioeconomic factors explain their adverse
position?
AB - OBJECTIVE: Differences in health, lifestyles, and use of health care between
groups of varying ethnic origin can have important implications for preventive
and curative health care. This paper studies whether socioeconomic factors
explain ethnic differences in these outcomes. DESIGN: Data on health status,
lifestyles, and use of health care were obtained from interviews with 3296 people
aged 16-64 years (response: 60.6%), among whom were 848 first generation
immigrants. Ethnic differences in these outcomes were examined with and without
adjustment for socioeconomic factors, using logistic regression. SETTING: General
population of Amsterdam, the Netherlands. MAIN OUTCOME MEASURES: Health status
(self rated health, General Health Questionnaire, functional limitations),
lifestyles (smoking, alcohol), and use of health care (general practice,
pharmaceuticals, hospitalisations). MAIN RESULTS: Immigrants from Turkey, Morocco
and (former) Dutch colonies report a poorer health and a higher use of health
care, especially primary health care among the elderly. An adverse socioeconomic
position partially explains the poor health of these immigrants. In turn, their
poor health explains most of their higher use of health care. CONCLUSIONS:
Cultural factors and poor living conditions seem to contribute to the poor health
of immigrants, besides an adverse socioeconomic position. The pressure on various
health services will increase in future because of the relatively high increase
in immigrants' needs at older ages and their presently low mean age.
PMID- 9764281
TI - Testing for Helicobacter pylori in primary care: trouble in store?
AB - STUDY OBJECTIVE: To assess the role of testing for Helicobacter pylori in the
management of dyspeptic patients in primary care. DESIGN: Selective review of
literature frequently quoted to support use of H pylori testing. MAIN RESULTS:
Testing for H pylori and referral of only positive cases for endoscopy aims to
reduce the number of "unnecessary" endoscopies. Patients with negative results
may receive short-term reassurance and subsequently place fewer demands on health
services. However, studies to date have only assessed this practice in secondary
care settings. Given the relatively high prevalence of both dyspepsia and H
pylori infection, the transfer of this practice to primary care may lead to a
paradoxical increase in endoscopy referrals. Identification of H pylori and
prescribing of eradication treatment also aims to reduce endoscopy referrals. No
primary care trials have yet assessed this approach. Given that fewer than one in
four of dyspeptic patients have peptic ulceration, a high proportion may fail to
respond to eradication treatment and subsequently require referral for endoscopy.
The longer term clinical and psychosocial sequelae of treating or labelling
patients with an infection associated with gastric cancer remain unknown.
CONCLUSIONS: Given uncertainty concerning the possible adverse effects of H
pylori testing in primary care, we suggest a moratorium on its use in this
setting until results from relevant clinical trials become available.
PMID- 9764282
TI - Midwifery care, social and medical risk factors, and birth outcomes in the USA.
AB - STUDY OBJECTIVE: To determine if there are significant differences in birth
outcomes and survival for infants delivered by certified nurse midwives compared
with those delivered by physicians, and whether these differences, if they exist,
remain after controlling for sociodemographic and medical risk factors. DESIGN:
Logistic regression models were used to examine differences between certified
nurse midwife and physician delivered births in infant, neonatal, and
postneonatal mortality, and risk of low birthweight after controlling for a
variety of social and medical risk factors. Ordinary least squares regression
models were used to examine differences in mean birthweight after controlling for
the same risk factors. STUDY SETTING: United States. PATIENTS: The study included
all singleton, vaginal births at 35-43 weeks gestation delivered either by
physicians or certified nurse midwives in the United States in 1991. MAIN
RESULTS: After controlling for social and medical risk factors, the risk of
experiencing an infant death was 19% lower for certified nurse midwife attended
than for physician attended births, the risk of neonatal mortality was 33% lower,
and the risk of delivering a low birthweight infant 31% lower. Mean birthweight
was 37 grams heavier for the certified nurse midwife attended than for physician
attended births. CONCLUSIONS: National data support the findings of previous
local studies that certified nurse midwives have excellent birth outcomes. These
findings are discussed in light of differences between certified nurse midwives
and physicians in prenatal care and labour and delivery care practices. Certified
nurse midwives provide a safe and viable alternative to maternity care in the
United States, particularly for low to moderate risk women.
PMID- 9764283
TI - Clinical significance not statistical significance: a simple Bayesian alternative
to p values.
AB - OBJECTIVES: To take the common "Bayesian" interpretation of conventional
confidence intervals to its logical conclusion, and hence to derive a simple,
intuitive way to interpret the results of public health and clinical studies.
DESIGN AND SETTING: The theoretical basis and practicalities of the approach
advocated is at first explained and then its use is illustrated by referring to
the interpretation of a real historical cohort study. The study considered
compared survival on haemodialysis (HD) with that on continuous ambulatory
peritoneal dialysis (CAPD) in 389 patients dialysed for end stage renal disease
in Leicestershire between 1974 and 1985. Careful interpretation of the study was
essential. This was because although it had relatively low statistical power, it
represented all of the data that were available at the time and it had to inform
a critical clinical policy decision: whether or not to continue putting the
majority of new patients onto CAPD. MEASUREMENTS AND ANALYSIS: Conventional
confidence intervals are often interpreted using subjective probability. For
example, 95% confidence intervals are commonly understood to represent a range of
values within which one may be 95% certain that the true value of whatever one is
estimating really lies. Such an interpretation is fundamentally incorrect within
the framework of conventional, frequency-based, statistics. However, it is valid
as a statement of Bayesian posterior probability, provided that the prior
distribution that represents pre-existing beliefs is uniform, which means flat,
on the scale of the main outcome variable. This means that there is a limited
equivalence between conventional and Bayesian statistics, which can be used to
draw simple Bayesian style statistical inferences from a standard analysis. The
advantage of such an approach is that it permits intuitive inferential statements
to be made that cannot be made within a conventional framework and this can help
to ensure that logical decisions are taken on the basis of study results. In the
particular practical example described, this approach is applied in the context
of an analysis based upon proportional hazards (Cox) regression. MAIN RESULTS AND
CONCLUSIONS: The approach proposed expresses conclusions in a manner that is
believed to be a helpful adjunct to more conventional inferential statements. It
is of greatest value in those situations in which statistical significance may
bear little relation to clinical significance and a conventional analysis using p
values is liable to be misleading. Perhaps most importantly, this includes
circumstances in which an important public health or clinical decision must be
based upon a study that has unavoidably low statistical power. However, it is
also useful in situations in which a decision must be based upon a large study
that indicates that an effect that is highly statistically significant seems too
small to be of practical relevance. In the illustrative example described, the
approach helped in making a decision regarding the use of CAPD in Leicestershire
during the latter half of the 1980s.
PMID- 9764284
TI - The Short-Form 36 and older people: some problems encountered when using postal
administration.
AB - OBJECTIVE: To explore some of the problems encountered in the postal
administration of the Short-Form 36 (SF-36). Questions that seem to present
particular difficulties for the group are identified. In addition some of the
written comments from the questionnaires and people's responses to questions on
how difficult they found the SF-36 are discussed. DESIGN: The study group were
asked to complete a health questionnaire containing the SF-36 on three separate
occasions (at zero, three, and six months). The first and final questionnaires
were interviewer administered during a face to face interview. A shorter
questionnaire containing only the SF-36 and another health status measure was
sent by post to each patient in the interim. PARTICIPANTS: People aged 65 years
or above who were new referrals to community based occupational therapy or
physiotherapy services in three areas in north west England. MAIN RESULTS:
Response and completion rates for the postal questionnaire were lower than
expected, even though all the patients had already had a face to face interview
and had therefore completed the SF-36 once. Only 34 of 56 respondents (60.7%)
completed all the items on the SF-36. CONCLUSIONS: All those planning to use the
SF-36 (and similar measures) with older populations should be sensitive to the
problems of postal administration. Non-return of questionnaires, high levels of
missing data on those that are received, and ambiguities in response may mean
that other measures, or perhaps alternative research methods, are more
appropriate.
PMID- 9764285
TI - Evaluation by Markov chain models of a non-randomised breast cancer screening
programme in women aged under 50 years in Sweden.
AB - STUDY OBJECTIVE: To apply Markov chain models that have previously been used on
data in randomised trials of breast cancer screening to data from an uncontrolled
service screening programme; to compare results with those from a randomised
trial. DESIGN: A service screening programme in Uppsala county, Sweden, inviting
25,660 women aged 39-49 to mammographic screening every 20 months, and the
Swedish Two-County Trial inviting 19,844 women aged 40-49 to two yearly
screening, compared with 15,604 women of the same age in an unscreened control
group. Data were analysed using Markov chain models and quasi-likelihood
estimation procedures. MAIN RESULTS: The results with respect to parameters of
disease progression were very similar between the two studies. Use of estimated
progression rates to predict the effect on mortality ranged from a 10% to a 17%
reduction in breast cancer mortality in the Two-County Study and predicted a 15%
reduction in the Uppsala programme. These compare well with the observed
mortality reduction of 13% in the Two-County Trial. CONCLUSIONS: The screening in
the Uppsala programme is likely to have a similar effect to that observed in the
Two-County Trial. It is feasible to evaluate non-randomised service screening
programmes using Markov chain models.
PMID- 9764286
TI - What's not in a name. The accuracy of using names to ascribe religious and
geographical origin in a British population.
PMID- 9764287
TI - How ordinary people in Great Britain perceive the health risks of smoking.
PMID- 9764288
TI - Dose classification.
PMID- 9764289
TI - The molecular genetics of inherited deafness--current and future applications.
PMID- 9764290
TI - How long should ears be bandaged after otoplasty?
AB - A firm head dressing is usually applied after otoplasty. Some surgeons recommend
that the patient should wear the bandage for up to 10 days after surgery.
However, these bandages are frequently displaced or come off. Patients complain
of reduced hearing, itch and the smell of old blood in the bandages. A case
series of 52 patients undergoing bilateral otoplasty who had a head bandage on
for only 24 hours was audited prospectively. Minor complications occurred in two
patients. A head bandage does not need to remain on for more than 24 hours after
otoplasty.
PMID- 9764291
TI - Cochlear implantation under local anaesthesia, the Belfast experience.
AB - The profoundly deaf, who gain little or no benefit from conventional hearing aids
and meet various criteria are potential candidates for cochlear implantation. The
last two decades have witnessed remarkable progress in this field, and it is now
a routine clinical procedure. A few adult patients who are potential candidates
for cochlear implantation have an unacceptably high risk for hypotensive general
anaesthesia due to other systemic conditions. This group has been successfully
implanted under local anaesthesia in our centre. The post-implantation progress
of these patients was comparable to those carried out under hypotensive general
anaesthesia. Data regarding patient selection criteria, examination, anaesthesia,
surgery and the outcome are discussed. It was concluded that cochlear
implantation under local anaesthesia is a safe and effective procedure for those
patients who otherwise may be denied an implant.
PMID- 9764293
TI - Closure of the nasal vestibule in atrophic rhinitis--a new non-surgical
technique.
AB - A new technique is described for closing the nasal vestibule in cases of
secondarily-acquired atrophic rhinitis. This involves occlusion of the nasal
vestibule with an obturator made from dimethylpolysiloxane. Being a non-invasive
method it is specifically indicated in the management of cases of secondarily
acquired atrophic rhinitis where any surgical treatment is contra-indicated. We
describe its use in a case each of unilateral and bilateral secondary atrophic
rhinitis.
PMID- 9764292
TI - Stability measurements of craniofacial implants by means of resonance frequency
analysis. A clinical pilot study.
AB - Nineteen patients previously treated with 52 implants for anchorage of
craniofacial prostheses were subjected to implant stability measurements by means
of resonance frequency analysis (RFA), six months to 15 years after implant
placement. The resonance frequency (RF) of a transducer attached to the implant
abutment was measured by using a frequency response analyser, a personal computer
(PC) and dedicated software. Statistically significant higher RF values were seen
for implants in the temporal bone as compared to implants in the nose and
periorbital regions. There was a positive correlation with time since implant
placement for the period from six months up to seven years. It was concluded that
the preliminary results suggest that implant stability increases with time and
that implants in temporal bone are more stable than implants in the bone in the
nose and periorbital regions, probably reflecting differences in bone density.
PMID- 9764294
TI - The 'swing-door' technique for uncinectomy in endoscopic sinus surgery.
AB - Uncinectomy is an important step in endoscopic sinus surgery. The traditional
method of performing uncinectomy has the risk of penetration of the lamina
papyracea with orbital fat exposure. If the orbital penetration is not
recognized, major complications may follow. In this study the authors used
historical consecutive controls to compare the incidence of orbital penetration,
identification of the natural ostium and lacrimal apparatus injury by the
traditional surgical technique and a new technique of uncinectomy. Six hundred
and thirty-six uncinectomies have been performed using the 'swing-door'
technique. The 636 uncinectomies performed prior to changing techniques were used
as historical controls. The incidence of orbital penetration (six compared to 0;
p < 0.05) and ostium non-identification (42 not identified as compared to 0; p <
0.001) was significantly less with the new technique. One lacrimal injury
occurred with the 'swing-door' technique compared to zero with the standard
technique (p > 0.05). The techniques are described and the complications
discussed. The authors recommend this technique as it is easy to learn, allows
removal of the uncinate flush with the lateral nasal wall and allows easy
identification of the natural ostium of the maxillary sinus.
PMID- 9764295
TI - Cyclin D1 expression as a prognostic factor in advanced hypopharyngeal carcinoma.
AB - Hypopharyngeal carcinoma (HPC) has a poor prognosis. We investigated the
expression of cyclin D1 in 34 advanced HPCs, and the value of cyclin D1
expression was evaluated as a predictive marker in terms of the prognosis of HPC,
compared with other clinical factors. Using immunohistochemical staining, 20 of
34 patients showed positive immunoreactivity for cyclin D1. The statistical trend
of the survival rate was lower in the cyclin D1-positive patients than in the
cyclin D-negative ones (p = 0.0805). The predictive factors for the survival rate
were effectiveness of neo-adjuvant chemotherapy (F = 8.698) (p = 0.0066), cyclin
D1 expression (F = 6.244) (p = 0.0191) and N classification (F = 5.037) (p =
0.0335). The cyclin D1-positive patients had approximately four-fold higher
mortality than the cyclin D1-negative ones. These data indicate that the
expression of cyclin D1, in advanced patients with hypopharyngeal carcinoma is a
useful marker for prognosis.
PMID- 9764296
TI - Microsurgical technique in thyroid surgery--a 10-year experience.
AB - OBJECTIVE: To report the results of thyroid surgery in a University department of
ENT--head and neck surgery, and to evaluate the benefits of the use of the
surgical microscope in thyroid surgery. DESIGN: A retrospective evaluation of the
records of all patients who underwent thyroid surgery in the 10-year period 1987
1996. METHODS: In addition to standard surgical principles the Zeiss multi
discipline universal surgical microscope with a 250 mm ocular lens was used in
all cases. Total thyroidectomy was performed in all malignant cases, while
unilateral lobectomy plus isthmus resection was the standard procedure in benign
cases. PATIENTS: There were 573 patients, aged 11-87 years, 444 females and 129
males. Four hundred and fifty-one had benign lesions, 122 malignant. Four hundred
and eighty-nine had primary surgery, 84 underwent completion surgery or surgery
for recurrent disease. RESULTS: Primary thyroid gland surgery in benign/malignant
disease resulted in permanent recurrent laryngeal nerve palsy in 0.6 per cent/3.5
per cent of the patients respectively, when calculated as nerves at risk (NAR).
In benign recurrent or malignant completion surgery this complication rate was
4.5 per cent/2.9 per cent respectively. CONCLUSION: Thyroid surgery in our
University ENT--Head and Neck Department with the use of the surgical microscope
provides pleasing results, especially considering the diversity of surgeons, due
to the departments' teaching responsibilities.
PMID- 9764297
TI - Use of a disposable electrode for recurrent laryngeal nerve monitoring.
AB - Our experience with a non-invasive, disposable electrode for intra-operative
identification and monitoring of the recurrent laryngeal nerve is described. The
electrode system, while simply attached to the endotracheal tube, acts as a
laryngeal surface electrode and detects electromyographic activity of the
intrinsic laryngeal muscles when the recurrent laryngeal nerve is stimulated. We
have successfully used this electrode to monitor 19 recurrent laryngeal nerves in
15 patients who have undergone partial or total thyroidectomy. We feel that this
device can be useful particularly in cases of re-exploration and malignancies of
the thyroid gland.
PMID- 9764298
TI - Aural papillomatosis--treatment with the carbon dioxide laser.
AB - Aural papillomatosis has been infrequently reported in the English literature. It
is a condition which can be very difficult to treat. We present the first
reported case of aural papillomatosis successfully treated with the CO2 laser.
PMID- 9764299
TI - Cochlear implantation in a patient with grand mal epilepsy.
AB - A case is reported in which a Nucleus 22 channel intracochlear implant was used
to treat a deaf Hungarian woman (aged 37 years) with a 34-year history of grand
mal (GM) epilepsy maintained on carbamazepine-diazepam combination therapy who
had not benefited from conventional hearing aids. Pre-operative electrical
stimulation of the acoustic nerve, however, exhibited a good nerve function with
no evidence of abnormal waveforms in the electroencephalogram (EEG). Successful
intracochlear insertion of the 22 electrode resulted in a 40 dB hearing
improvement at frequencies 250-2000 Hz in the implanted ear with no signs of
pathologic wave activity at either the previously recognized epileptic focus
(fronto-precentral region) or indeed, in other regions of the brain at use of the
implant. We conclude that intracochlear implantation per se is not a hazardous
intervention in patients with fronto-precentral epileptic foci.
PMID- 9764300
TI - Frontal sinolith.
AB - We report on a case of an endogenous frontal sinolith and a literature review of
classification and use of the terms rhinolith, and sinolith.
PMID- 9764301
TI - Rheumatoid nodules of the larynx.
AB - A 67-year-old woman with rheumatoid arthritis was hospitalized because of
dysphagia and severe nodulosis. Over a two-year period the patient had been
treated with methotrexate. A computed tomography (CT) scan of the neck showed a 2
x 2 cm large tumour behind the top left lateral thyroid cartilage. A biopsy taken
during direct laryngoscopy showed it was a rheumatic nodule. Treatment with
colchicine reduced the patient's dysphagia. As methotrexate is used increasingly
in the treatment of rheumatoid arthritis and as this particular drug causes
rheumatic nodules in five to 10 per cent of the patients, it must be foreseen
that the incidence of nodules in the upper airways will increase.
PMID- 9764302
TI - Invasive laryngeal candidiasis: a cause of stridor in the previously irradiated
patient.
AB - Upper airway obstruction is always a serious condition. In patients who have
previously been irradiated for a laryngeal malignancy, it normally implies either
residual or recurrent disease. We report a case of stridor due to invasive
laryngeal candidiasis in a patient who had undergone radiotherapy for a T1a N0
squamous cell carcinoma of the glottis eight months earlier. Extensive
investigation failed to identify recurrence of disease and the patient responded
to prolonged topical antifungal therapy. Infection with Candida species is most
frequently found in debilitated or immunocompromised patients. Although cases of
upper airway obstruction in children secondary to idiopathic laryngeal
candidiasis have been reported, to our knowledge no such presentation has been
described in adults. This report highlights the difficulty of diagnosis and
treatment. Familiarity with candidal infection is important for early diagnosis
and appropriate treatment.
PMID- 9764303
TI - Primary tuberculous tracheitis.
AB - We report a case of primary tuberculous tracheitis in an otherwise healthy woman
who presented with cough and stridor due to diffuse tracheal narrowing by
tuberculous pseudomembranous lesion, which resolved completely with
antituberculosis chemotherapy.
PMID- 9764304
TI - Tonsillar metastasis from malignant pulmonary carcinoid tumour.
AB - Tumour metastases to the tonsil are rare and are usually due to spread from
malignant melanoma and carcinomas of the breast, lung, kidney or stomach. We
describe the clinical and histological findings of a tonsillar metastasis from a
malignant pulmonary carcinoid tumour, an occurrence not previously reported.
PMID- 9764305
TI - Recurrent unilateral tonsillitis secondary to a penetrating foreign body in the
tonsil.
AB - We report a case of an impacted foreign body in the tonsil presenting as
recurrent unilateral tonsillitis. A completely embedded foreign body should be
considered in cases of recurrent unilateral tonsillitis.
PMID- 9764306
TI - Tuberculosis of the mandible in a child.
AB - The incidence of notification of tuberculosis is increasing in the developed
world. The disease has a variable mode of presentation and therefore diagnosis is
not easy. We present an unusual case of tuberculosis involving the ramus of the
mandible in a six-year-old boy and outline its management.
PMID- 9764307
TI - Tuberculosis of the parotid gland.
AB - The presentation of tuberculosis as an isolated parotid lump is rare. In this
paper, six cases with tuberculous parotitis are reported which were evaluated as
a benign parotid neoplasm in 216 specimens pre-operatively. All but one of them
had no previous history of tuberculosis and all had a parotid lump as a sole
symptom for at least one year. The diagnosis of tuberculosis was made, after
superficial parotidectomy, by histopathology. Parenchymal involvement and
intraparotid lymph node involvement with tuberculosis were seen in five and three
patients, respectively. Two of the patients had lymph node involvement outside
the parotid area. One of six patients had a coincidental Warthin tumour. A
surgical approach is not only therapeutic but also diagnostic when other
diagnostic tools fail.
PMID- 9764308
TI - Lymphoblastic lymphoma/leukaemia presenting as perichondritis of the pinna.
AB - Extra-nodal non-Hodgkin's lymphoma (NHL) of the pinna has only been reported once
in a patient with immunodeficiency. We report an unusual case of lymphoblastic
lymphoma in a patient without any immunodeficiency, presenting as an inflammatory
lesion of the pinna, which illustrates the need to biopsy any non-healing lesion
as soon as possible to ensure that such a treatable malignancy is diagnosed at an
early stage.
PMID- 9764309
TI - The use of magnetic resonance imaging to assess tracheal stenosis following
percutaneous dilatational tracheostomy.
PMID- 9764310
TI - Transport and transformations of yolk lipids during development of the avian
embryo.
PMID- 9764311
TI - Phytooxylipins and plant defense reactions.
PMID- 9764312
TI - Health care in refugee camps.
PMID- 9764313
TI - Royal Society of Tropical Medicine and Hygiene meeting at Manson House, London,
20 March 1997. Epidemiology and control of rabies. The growing problem of rabies
in Africa.
AB - Although rabies in Africa is relatively insignificant in terms of human
mortality, the disease is still relevant because of the high costs of rabies
prevention. Over the past 2 decades, demographic, economic and sociopolitical
trends in Africa have increasingly favoured the persistence and spread of rabies,
while limiting the effectiveness of control measures. Dog rabies predominates
throughout most of Africa; the domestic dog is the principal reservoir host as
well as the most important source of infection for people. However, wild-life
rabies is increasingly a concern, both as a threat to endangered wildlife
populations and because of the possible emergence of new maintenance hosts.
PMID- 9764314
TI - Comparison of the effect of insecticide-treated bed nets and DDT residual
spraying on the prevalence of malaria transmitted by Anopheles anthropophagus in
China.
AB - In order to improve the control of malaria in a problem part of Hubei Province,
China, where Anopheles anthropophagus is the vector of Plasmodium vivax,
insecticide treatment of bed nets was introduced. The people were given the
choice of DDT residual spraying, which had been used for many years, or
deltamethrin treatment of their bed nets. Two counties, in which these 2
different methods had been introduced, and an untreated area were evaluated. DDT
house spraying and insecticide treated bed nets were equally effective, but
deltamethrin treatment was cheaper and so was considered the method of choice.
PMID- 9764315
TI - A cost-benefit analysis of Chagas disease control in north-western Argentina.
AB - Chagas disease has been controlled in the Department of Anta, Province of Salta,
Argentina, through a series of vector control interventions beginning in 1983.
Based on data from this programme, together with estimates of the value of
benefits accruing to the programme due to avoidance of new cases of Chagas
disease, we present an analysis of costs and benefits of the vector control
interventions. Under all assumptions, the interventions have been highly
profitable from a societal point of view, with an internal rate of return in
excess of 60%. The net present value of benefits accruing to the programme is
estimated to be above US$7 million.
PMID- 9764316
TI - The proportion of helminth infections in a community in western Kenya which would
be treated by mass chemotherapy of schoolchildren.
AB - The present study used data from a community-based epidemiological survey of 752
persons in 3 villages in Kisumu District, western Kenya, to examine the
proportion of infected persons who would be treated, as well as the effect on
helminth egg production, if anthelmintics were provided to schoolchildren.
Overall prevalences of hookworm, Ascaris lumbricoides, Trichuris trichiura and
Schistosoma mansoni infections were 63%, 16%, 24% and 24% respectively, and
intensities were low for all infections. Only 79% of the school-aged children
were enrolled. For all 4 infections, a school-based programme would treat between
76% and 86% of infected school-age children and would theoretically eliminate
between 83% and 92% of the number of eggs excreted by this age group. Of the
total population, school-based programmes would treat only between 31% and 50% of
the infected persons and eliminate only 15%, 46%, 29% and 27% of the total number
of hookworm, Ascaris, Trichuris and S. mansoni eggs excreted, respectively.
Provided that school attendance rates were high in the study area, school-based
programmes would be efficient in improving the helminth infection status of
school-aged children. On the other hand, adults, non-enrolled school-aged
children and preschool children not offered treatment represented more than half
of the helminth-infected persons and they excreted between half and 85% of the
total burden of helminth eggs in the area. Hence, mass chemotherapy of
schoolchildren would be less effective in the control of at least hookworm and S.
mansoni infections in this specific community. There should therefore be a
community-based approach to helminth control in combination with a school-based
programme.
PMID- 9764317
TI - Correlation between positive serology for Plasmodium vivax-like/Plasmodium
simiovale malaria parasites in the human and anopheline populations in the State
of Acre, Brazil.
AB - Antibodies against the Plasmodium vivax-like/P. simiovale malaria parasite
circumsporozoite repeat peptide (APGANQEGGAA)3 were determined by enzyme-linked
immunosorbent assay (ELISA) in 120 sera randomly collected in 1994 from adults in
3 localities of the malaria endemic area in the State of Acre, Brazil; antibody
was detected in 18 (15%). A 'sandwich' ELISA using monoclonal antibody (mab) Pam
172, directed against the same peptide, was carried out on 1207 Anopheles
oswaldoi, 12 of which (1.0%) were positive, and 168 A. deaneorum, 2 of which
(1.2%) were positive. This is the first report of serological detection of the P.
vivax-like parasite in anophelines and the first report linking anopheline to
human serology for this parasite in the same geographical area. It is an
additional indication that A. oswaldoi is a malaria vector in Acre.
PMID- 9764318
TI - The role of four anopheline species (Diptera: Culicidae) in malaria transmission
in coastal Tanzania.
AB - Malaria is holoendemic in coastal Tanzania with Anopheles funestus and members of
the A. gambiae complex being mainly responsible for transmission. Over a 4
months' sampling period 2222 anopheline mosquitoes were collected using light
traps and indoor resting catches, of which 58.6% were A. gambiae, 7.6% A.
arabiensis, 6.9% A. merus and 26.9% A. funestus. Plasmodium falciparum
circumsporozoite antigen (CSA) rates were: A. funestus 6.05% (n = 479), A.
gambiae 8.4% (n = 1042), A. arabiensis 7.3% (n = 136) and A. merus 9.8% (n =
122). The P. malariae CSA rate for all anophelines was 0.07% (n = 1862).
Estimated sporozoite densities were less than 2000 for at least 50% of all the
positive mosquitoes. Along the coast the abundance of A. merus (41.3%) and A.
gambiae (46.1%) was similar, and their CSA rates were comparable (11.6% and
12.5%, respectively) and higher than those for A. arabiensis (7.7%) and A.
funestus (4.6%). These results indicate that A. merus plays an unexpectedly
important role in malaria transmission in coastal Tanzania.
PMID- 9764319
TI - Phylogenetic species and domesticity of Lutzomyia whitmani at the southeast
boundary of Amazonian Brazil.
PMID- 9764320
TI - Prevalence of tuberculosis in TB suspects with short duration of cough.
AB - The prevalence of pulmonary tuberculosis (PTB) in patients with short duration of
cough was determined. Ninety-eight adult out-patients (60 men, 38 women; mean age
32 years) at Queen Elizabeth Central Hospital, Blantyre, Malawi, who had cough
for 1-3 weeks which was unresponsive to a course of antibiotics, were
successfully screened by microscopy and culture of 2 or 3 sputum specimens and
chest radiography; 34 (35%) had PTB. Ten patients were sputum smear-positive and
24 were smear-negative and culture-positive. There was no difference in age,
gender or clinical features of general illness, respiratory disease and HIV
related disease between patients with PTB and those with no evidence of PTB. Nine
patients (26%) with microbiologically confirmed tuberculosis (TB) had chest
radiograph abnormalities consistent with TB, compared with 5 (8%) of patients
with no microbiological evidence of TB. Certain classes of patients with a short
history of cough would benefit from PTB screening strategies with the emphasis on
sputum examination rather than chest radiography, which is unreliable in such
patients. The classes include (i) patients with other features of TB whose cough
has not improved with antibiotic therapy, (ii) seriously ill patients, and (iii)
patients in high risk institutions such as prisons and refugee camps.
PMID- 9764321
TI - Aetiology of cholera in Tamil Nadu: recent observations.
AB - Vibrio cholerae was isolated from 1008 of 3496 stool samples (28.8%) examined in
Tamil Nadu State, India, between November 1992 and December 1995. During November
and December 1992, 363 of the 370 isolates serotyped (98%) were V. cholerae O139
(Bengal). The epidemic predominantly affected adults (91%; 597/656). Both V.
cholerae O1 and O139 serotypes were sometimes isolated in the same locality from
different individuals. From January 1993 onwards, the rate of isolation of V.
cholerae O139 declined, and in 1995 V. cholerae E1 Tor (serotype O1) was isolated
from most of the cases (85.6%; 131/153). V. cholerae E1 Tor has clearly not been
replaced by serotype O139, but can survive during inter-epidemic periods and
reappear at an opportune moment. The decline of serotype O139 may be due to the
development of immunity as a result of repeated exposure.
PMID- 9764322
TI - Comparison of the ParaSight-F test and the ICT Malaria Pf test with the
polymerase chain reaction for the diagnosis of Plasmodium falciparum malaria in
travellers.
AB - Rapid and accurate methods are needed for the diagnosis of imported malaria. The
ParaSight-F test and the ICT Malaria Pf test are commercially available kits
marketed for the diagnosis of Plasmodium falciparum malaria. Both tests are
antigen-capture assays based on the detection of P. falciparum histidine-rich
protein 2 in peripheral blood. Using microscopy and a polymerase chain reaction
(PCR)-based method as reference standards, we performed a 'blinded' comparison of
these assays for the detection of P. falciparum infection in 200 febrile
travellers returning from malaria-endemic areas. As determined by PCR and
microscopy, 148 travellers had malaria and, of these patients, 54.7% (81/148)
were infected with P. vivax only, 31.1% (46/148) with P. falciparum only, 9.5%
(14/148) with P. ovale, 0.7% (1/148) with P. malariae, and 4.1% (6/148) had mixed
infections. Compared to PCR, the ParaSight-F and ICT Malaria Pf tests had initial
sensitivities of 94% and 90% and specificities of 95% and 97%, respectively, for
the detection of P. falciparum malaria. When discrepant samples were retested
with day 0 and day 1 bloods, the sensitivities improved to 96% and 94%,
respectively. The 2 remaining false negative results with the Para-Sight-F test
and 2 of the 3 false negative results with the ICT Malaria Pf test occurred in
samples with < 100 parasites/microL. The performance of these kits was not
significantly different (P = 0.75) and both are simple, rapid, and accurate tests
for the detection of P. falciparum infection in the returned traveller.
PMID- 9764323
TI - Reactive nitrogen intermediates and outcome in severe adult malaria.
AB - The role of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) in the
pathophysiology of severe falciparum malaria remains unclear. We conducted a
retrospective case-control study of Vietnamese adults with severe malaria to
determine the relationship between outcome and admission plasma reactive nitrogen
intermediates (RNI), the stable metabolites of NO. The study was designed to take
into account the potential confounders of recent dietary nitrogen intake and
renal function. Seventy-six patients who died from severe malaria were matched
for age and sex with 76 survivors from a prospectively studied series of 560
patients. Median untransformed unadjusted plasma RNI levels were slightly higher
in fatal cases (45 mumol/L, range 0-482) than in survivors (24.1 mumol/L, range
1.4-466) (P = 0.031, Wilcoxon signed-rank). There was a significant positive
correlation between RNI levels and plasma creatinine (Spearman's rho = 0.35, P <
0.0001), and the addition of plasma creatinine as a covariate in a multivariate
analysis abolished the trend towards higher RNI levels in fatal cases (P for the
coefficient for RNI = 0.96). There was no association between RNI levels and
either depth of coma on admission or time to regain consciousness. These findings
do not support a pivotal role for systemic generation of NO in the pathogenesis
of severe malaria in general, or cerebral malaria in particular.
PMID- 9764324
TI - Estimating Plasmodium vivax parasitaemia.
PMID- 9764325
TI - Post kala-azar ocular leishmaniasis.
AB - The clinical features, diagnosis and treatment of 6 patients with post kala-azar
ocular leishmaniasis are described. The eye lesions were associated with past or
concomitant post kala-azar dermal leishmaniasis (PKDL). Four patients had post
kala-azar leishmanial conjunctivitis and blepharitis. Using the polymerase chain
reaction, the causative parasite was characterized as Leishmania donovani in 2 of
these 4 patients. Two patients had post kala-azar anterior uveitis. The diagnosis
of uveitis was based on the clinical manifestations, temporal relation to treated
visceral leishmaniasis, the association with PKDL and positive anti-Leishmania
serology. All patients were treated with systemic sodium stibogluconate. Patients
with anterior uveitis were also treated with steroid and atropine eyedrops. The
response to treatment was good. The importance of early diagnosis and treatment
of ocular leishmaniasis is stressed.
PMID- 9764326
TI - Human diphyllobothriasis: first report from India.
PMID- 9764327
TI - Salmonella meningitis in Thai infants: clinical case reports.
AB - Between June 1988 and September 1996 12 of 65 infants (18%) admitted to the
Department of Pediatrics, Ramathibodi Hospital, Bangkok, Thailand with purulent
meningitis were infected with Salmonella spp. Their ages ranged from 1.5 to 6
months. Six of the infants had diarrhoea, 9 had seizures, and 11 had subdural
effusion or empyema. Six infants required surgical treatment; 2 had brain
abscesses. Salmonella was recovered from the cerebrospinal fluid of 11 infants
and from the subdural fluid of 10. Eight infants were successfully treated with
cefotaxime alone or in combination with co-trimoxazole, one with co-trimoxazole,
and one with the combination of co-trimoxazole and ampicillin. The duration of
treatment was 6 weeks, except for one patient who had a large brain abscess and
was treated for 8 weeks. The last 2 patients, despite the fact that the organisms
were susceptible to cefotaxime, failed to respond clinically to appropriate doses
of it. Both were cured after ciprofloxacin was added to the therapy.
Ciprofloxacin is probably the drug of choice to be used in addition to the
previously used antibiotics for severe cases of Salmonella meningitis in infants.
PMID- 9764328
TI - Dual infection with Vibrio cholerae serogroups O1 and O139.
PMID- 9764329
TI - First report of human leptospirosis due to Leptospira interrogans serovar
javanica in India.
PMID- 9764330
TI - Hypercalcaemia and paracoccidioidomycosis.
PMID- 9764331
TI - The evolution of multiple drug resistance in malaria parasites.
AB - Forces determining the rate of spread of drug resistance in malaria were explored
using a genetics transmission model which took account of the strong population
structure of these parasites. The rate of change of frequency of drug resistant
mutants in the parasite population is primarily a function of the proportion of
hosts treated with drugs, and parasite transmission rates. With high transmission
rates, selection by drugs is more effective than with lower rates because the
resistant mutant passes on more copies of itself to the next generation of hosts.
Thus reducing transmission rates, either at the overall population level or from
drug-treated individuals, should be effective in curbing the spread of
resistance. An exception to this is when 2 unlinked genes act jointly (not
independently) to confer resistance, when the prevailing transmission rate is
already low, drug use is minimal, and resistance genes are rare. Reductions in
fitness of the mutant in the absence of drugs (i.e., a fitness cost to
resistance) and the degree of epistasis and the mode of gene action of the drugs
do not alter these conclusions.
PMID- 9764332
TI - Quinine sensitivity of isolates of Plasmodium falciparum from the coast of Kenya.
PMID- 9764333
TI - Resistance in vivo of Plasmodium falciparum to co-trimoxazole in western Uganda.
AB - In the context of the 'integrated management of childhood illnesses' (IMCI)
programme the World Health Organization recommends treating children in malarious
areas presenting with fever and respiratory symptoms with co-trimoxazole. In
order to verify its effectiveness in uncomplicated Plasmodium falciparum malaria
we carried out a study in vivo in western Uganda: 180 children under 5 years old
were enrolled and treated with 40/8 mg/kg/d co-trimoxazole over 5 d, and 159
could be followed on days 3, 7 and 14. Effectiveness of treatment was found to be
significantly different in various parts of the study area. In Bundibugyo
District, bordering Republique Democratique du Congo (Zaire), 59.1% (39/66) of
children were clinically cured after 14 d and 56.1% were parasitologically cured.
In the east of Kabarole District (43 children), the figures were 76.7% and 65.1%,
respectively. In western Kabarole (50 children) the rates were 96.0% and 90.0%,
respectively. We conclude that, in view of the high level of clinical failures in
parts of the study area, co-trimoxazole should not be used in the IMCI programme
for combined treatment of malaria and pneumonia in the region. Assessment of
therapeutic effectiveness of antimalarial drugs needs to consider the
microepidemiology of resistance.
PMID- 9764334
TI - Efficacy and pharmacokinetics of atovaquone and proguanil in children with
multidrug-resistant Plasmodium falciparum malaria.
AB - A trial was conducted in 32 Thai children with uncomplicated multidrug-resistant
falciparum malaria to assess the efficacy, safety and pharmacokinetics of
atovaquone and proguanil; plasma concentrations of atovaquone, proguanil and its
metabolite, cycloguanil, were measured in a subset of 9 children. The children
received atovaquone (17 mg/kg/d for 3 d) plus proguanil (7 mg/kg/d for 3 d).
Twenty-six children who had only Plasmodium falciparum infection and remained in
hospital for 28 d were assessed for drug efficacy. The combination regimen
produced a cure rate of 100%. Parasite and fever clearance times were 47 h (range
8-75) and 50 h (range 7-111), respectively. Atovaquone and proguanil were rapidly
absorbed, with median time to peak concentrations of 6 h (range 6-24) and 6 h
(range 6-12), respectively. Peak concentrations of cycloguanil were achieved
between 6 and 12 h (median 6) after administration of proguanil. Mean peak plasma
concentration of atovaquone on day 3 was 5.1 micrograms/mL (SD = 2.1). The day 3
mean peak plasma concentration of proguanil was 306 ng/mL (SD = 108) compared
with 44.3 ng/mL (SD = 27.3) for cycloguanil. Mean values for the AUC (area under
plasma concentration-time curve) were 161.8 micrograms/mL.h (SD = 126.9) for
atovaquone, 4646 ng/mL.h (SD = 1226) for proguanil, and 787 ng/mL.h (SD = 397)
for cycloguanil. Terminal elimination half-lives of atovaquone, proguanil and
cycloguanil were estimated as 31.8 h (SD = 8.9), 14.9 h (SD = 3.3) and 14.6 h (SD
= 2.6), respectively. No major adverse effect was attributable to the study
drugs. Atovaquone/proguanil combination is safe and highly effective, and should
be especially valuable for treatment of multidrug-resistant falciparum malaria.
PMID- 9764335
TI - Artesunate and mefloquine in the treatment of uncomplicated multidrug-resistant
hyperparasitaemic falciparum malaria.
AB - Oral artesunate is the most effective treatment for uncomplicated
hyperparasitaemia in falciparum malaria. To assess the contribution of mefloquine
to therapeutic efficacy in an area endemic for mefloquine-resistant Plasmodium
falciparum, an open randomized comparison of a 5 d course of oral artesunate
(total dose 12 mg/kg) with and without a single dose of mefloquine (25 base
mg/kg) was conducted in 100 adults and children with uncomplicated
hyperparasitaemia (> 4% parasitized red blood cells). Both regimens were well
tolerated and gave equally rapid clinical responses (84% of patients were
aparasitaemic and 96% were afebrile within 48 h), but the recrudescence rate
assessed at day 42 was 6% in those receiving artesunate with mefloquine compared
to 36% in those receiving artesunate alone (adjusted hazard ratio 7, 95%
confidence interval [95% CI] 2-32; P < 0.01). In addition, the efficacy of a 7 d
course of artesunate, with and without the addition of mefloquine, was monitored
in 178 patients who were not part of the randomized comparison. The failure rate
was again lower in those receiving artesunate and mefloquine--7% (95% CI 2-13)
compared with 26% (95% CI 8-44) in patients treated with artesunate alone. An
oral regimen of 5 d or more of artesunate, together with mefloquine (25 mg/kg)
given on day 2, is an effective treatment for uncomplicated hyperparasitaemic
falciparum malaria in this area of high level multidrug resistance.
PMID- 9764336
TI - Amodiaquine as the first-line treatment of malaria in Yaounde, Cameroon:
presumptive evidence from activity in vitro and cross-resistance patterns.
PMID- 9764338
TI - Direct assessment in vivo of the efficacy of combined single-dose ivermectin and
diethylcarbamazine against adult Wuchereria bancrofti.
AB - When ivermectin and diethylcarbamazine (DEC) are given simultaneously in a single
dose to persons with Wuchereria bancrofti infection, the resulting suppression of
microfilaraemia is more profound and sustained than when either drug is given
alone. To assess whether this effect is a result of enhanced macrofilaricidal
efficacy, we used ultrasound to monitor the adult worms in the scrotal area of
men with W. bancrofti microfilaraemia. Twenty-one men were treated simultaneously
with DEC (6 mg/kg) and either 200 micrograms/kg or 400 micrograms/kg of
ivermectin (11 and 10 men, respectively). Ten other men received a single 200
micrograms/kg dose of ivermectin followed 5 d later by a 6 mg/kg dose of DEC
(sequential treatment). All men became amicrofilaraemic after treatment and all
except one remained so for one year. Cessation of adult worm movement, indicative
of death of all the adult worms in a given 'nest', was observed in none of 30
nests in men who received simultaneous treatment and in 3 of the 19 nests (16%)
in the men who received sequential treatment (P = 0.05). Scrotal nodules were
detected in 5 of 21 men (24%) who received simultaneous treatment and in 8 men
(80%) who received sequential treatment (P < 0.01). Thus, co-administration of
ivermectin with DEC seems to interfere with the macrofilaricidal action of DEC.
These findings have implications both for treatment of the individual patient and
for community-based drug distribution programmes designed to interrupt
transmission of W. bancrofti.
PMID- 9764337
TI - Effect of iron chelation therapy on mortality in Zambian children with cerebral
malaria.
AB - To examine the effect of iron chelation on mortality in cerebral malaria, we
enrolled 352 children in a trial of deferoxamine in addition to standard quinine
therapy at 2 centres in Zambia, one rural and one urban. Entrance criteria
included age < 6 years, Plasmodium falciparum parasitaemia, normal cerebral
spinal fluid, and unrousable coma. Deferoxamine (100 mg/kg/d infused for a total
of 72 h) or placebo was added to a 7 d regimen of quinine that included a loading
dose. Mortality overall was 18.3% (32/175) in the deferoxamine group and 10.7%
(19/177) in the placebo group (adjusted odds ratio 1.8; 95% confidence interval
0.9-3.6; P = 0.074). At the rural study site, mortality was 15.4% (18/117) with
deferoxamine compared to 12.7% (15/118) with placebo (P = 0.78, adjusted for
covariates). At the urban site, mortality was 24.1% (14/58) with deferoxamine and
6.8% (4/59) with placebo (P = 0.061, adjusted for covariates). Among survivors,
there was a non-significant trend to faster recovery from coma in the
deferoxamine group (adjusted odds ratio 1.2; 95% confidence interval 0.97-1.6; P
= 0.089). Hepatomegaly was significantly associated with higher mortality, while
splenomegaly was associated with lower mortality. This study did not provide
evidence for a beneficial effect on mortality in children with cerebral malaria
when deferoxamine was added to quinine, given in a regimen that included a
loading dose.
PMID- 9764339
TI - Treatment of human lagochilascariasis with ivermectin: first case report from
Ecuador.
PMID- 9764340
TI - Plasmodium falciparum: genetic polymorphism of the merozoite surface antigen 2
gene of strains from India.
PMID- 9764341
TI - Measles antibody levels in a vaccinated population in Brazil.
AB - An epidemiological study of measles-specific immunoglobulin G antibody levels was
conducted using a representative sample of a vaccinated suburban population in
Sao Paulo State, Brazil. The study aimed to determine immunity status in relation
to age and infection or vaccination experience. 549 age-structured samples of
sera, collected in 1990, were screened and calibrated to the international
reference serum, using measles nucleoprotein in an enzyme immunoassay. In the age
group with direct experience of vaccination (9 months to 15 years), whether
routine or campaign, over 90% had detectable antibody > or = 50 miu/mL. However,
14% of these had antibody concentrations between 50 and 100 miu/mL and 30%
between 50 and 255 miu/mL. In those over 15 years of age, 94% had antibody levels
> 255 miu/mL, assumed to be the result of past infection. The study suggested
that, within highly vaccinated populations, a proportion of individuals had
measles antibody levels which may be insufficient to protect against reinfection
or clinical disease. The implications of these results, and similar findings
elsewhere, in relation to the persistence of measles requires investigation; this
has particular relevance in Sao Paulo following the recent measles outbreak.
PMID- 9764342
TI - The Anopheles gambiae complex: a new species from Ethiopia.
AB - Historically, members of the Anopheles gambiae complex from Ethiopia have been
identified chromosomally as either A. arabiensis or A. quadriannulatus. Recent
collections from the Jimma area in Ethiopia, southwest of Addis Ababa, revealed
29 specimens of A. quadriannulatus based on the standard polymerase chain
reaction (PCR) identification method. 'Wild' females were induced to lay eggs and
the progeny reared as individual families. Resulting adults were cross-mated to a
laboratory colony strain of A. quadriannulatus originating from the Kruger
National Park, South Africa. Hybrid progeny were obtained only from the colony
female x Ethiopian male cross. This cross produced a female/male sex ratio of
0.48. Male offspring were sterile and ovarian polytene chromosomes from hybrid
females showed typical asynapsis as expected in interspecific crosses within the
A. gambiae complex. The X chromosomes, although apparently having homosequential
banding patterns, were usually totally asynapsed. All autosomes were
homosequential. The lack of inversion heterozygotes, in both the wild and hybrid
samples, may simply be a reflection of the small sample size. Until such time as
the Ethiopian species can be formally described and assigned a scientific name,
it is provisionally designated Anopheles quadriannulatus species B because of its
close similarity to this species.
PMID- 9764343
TI - Asymptomatic Plasmodium falciparum parasitaemia in pregnant women.
PMID- 9764345
TI - The Varna meeting resumes after 10 years.
PMID- 9764344
TI - Onchocerciasis, epilepsy and hyposexual dwarfism.
PMID- 9764347
TI - Levels of antibodies to transferrin and alpha 2-HS glycoprotein in women with and
without endometriosis.
AB - PROBLEM: To establish an enzyme-linked immunosorbent assay (ELISA) for
determining the levels of antibodies to transferrin and alpha 2-HS glycoprotein
in the serum of women with and without endometriosis. METHOD OF STUDY: Serum
samples were obtained from 105 normal women, who were randomly selected for a
population-based epidemiologic study, and 123 patients with active endometriosis.
An ELISA using transferrin and alpha 2-HS glycoprotein as antigens was
established. RESULTS: The levels of antibodies to transferrin and alpha 2-HS
glycoprotein in the serum of patients with endometriosis were approximately 21
times higher than those in the serum of control subjects without endometriosis.
Only 2% of control subjects had false positive levels of these antibodies, and 5%
of patients with endometriosis had false negative levels of these antibodies
(specificity, 98.1 and 98.1, respectively, for anti-transferrin and anti-alpha 2
HS glycoprotein; sensitivity, 95 and 96.7, respectively, for anti-transferrin and
anti-alpha 2-HS glycoprotein). CONCLUSIONS: Patients with endometriosis have
significantly higher levels of antibodies to transferrin and alpha 2-HS
glycoprotein than control subjects. Testing women for antibodies to transferrin
and alpha 2-HS glycoprotein will provide a specific noninvasive diagnosis of
endometriosis.
PMID- 9764348
TI - The selective use of heparin/aspirin therapy, alone or in combination with
intravenous immunoglobulin G, in the management of antiphospholipid antibody
positive women undergoing in vitro fertilization.
AB - PROBLEM: The effect of mini-dose heparin/aspirin (H/A) alone vs. combined
intravenous immunoglobulin G (IVIg) and H/A on in vitro fertilization (IVF)
birthrates in women who test seropositive for antiphospholipid antibodies (APA+)
was evaluated, as was the question of whether outcome is influenced by the
gammaglobulin isotype(s) or the phospholipid (PL) epitope(s) to which the APAs
are directed. METHOD OF STUDY: A case-control study was conducted in three
phases, spanning a 4-year period, in a multicenter clinical research environment.
Six hundred eighty-seven APA+ women, who were younger than 40 years and who each,
completed up to three consecutive IVF/embryo transfer cycles within a 12-month
period, were given either H/A alone or H/A in combination with IVIg. Birthrates
relative to the type of immunotherapy (i.e., H/A alone and H/A with IVIg) and APA
profile were the main outcome measurements. RESULTS: In phase I, 687 women who
tested APA+ to one or more PL epitopes underwent two or fewer IVF attempts for a
total of 1050 IVF cycles. Four hundred seventy-seven (46%) births occurred in 923
IVF cycles in which H/A alone was administered. Twenty-two (17%) births occurred
after 127 IVF cycles in which H/A was not administered. In phase II, 322 of 687
women tested positive for a single APA subtype. These subjects underwent up to
two consecutive IVF attempts for a total of 521 IVF cycles while receiving H/A
alone. The birthrate was significantly lower for women whose APAs were directed
toward phosphatidylethanolamine (PE) or phosphatidylserine (PS) involving IgG or
IgM isotypes than for women who had any other APA (17% vs. 43%). In phase III,
121 women who did not achieve live births after two consecutive IVF attempts in
which H/A alone was administered received IVIg in combination with H/A during
their third consecutive IVF cycle. The birth rate was 41% after these IVF cycles
when anti-PS or anti-PE involving IgG or IgM isotypes were present, as compared
with 17% when H/A alone was administered. The IVF outcome did not improve when
IVIg was administered in association with any other single APA. CONCLUSIONS: The
treatment of APA+ women with H/A alone improves IVF birthrates. This benefit is
selective in that it does not apply in cases in which IgG- or IgM-related APAs
are directed against PE or PS. In such cases, the addition of IVIg significantly
improves the outcome.
PMID- 9764349
TI - Effect of human chorionic gonadotropin on cytokine production from human
endometrial cells in vitro.
AB - PROBLEM: To examine whether human chorionic gonadotropin (hCG) is involved in the
regulation of interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and leukemia
inhibitory factor (LIF) secretion from cultured human endometrial cells. METHOD
OF STUDY: A mixed population of endometrial cells from six in vitro
fertilization/embryo transfer patients was cultured and incubated with various
doses of hCG (0, 1, 10, 50, 100, and 500 IU/ml) for 24 hr. IL-6, TNF-alpha, and
LIF levels in the culture medium were measured with enzyme-linked immunosorbent
assay. RESULTS: IL-6 and TNF-alpha levels were stimulated by hCG in a dose
dependent manner. Stimulation of IL-6 and TNF-alpha levels by 500 IU/ml of hCG
increased their production by 3.7- and 2.8-fold, respectively (P < 0.05).
Stimulation of IL-6 by 100 IU/ml of hCG was also significant (P < 0.05). However,
there was no significant effect of hCG on LIF secretion by endometrial cells (P =
0.31). CONCLUSIONS: hCG is involved in the regulation of endometrial cytokine
production from human endometrial cells in vitro. This finding supports the
recently emerging notion that hCG could have important local roles within the
uterus besides its well-known luteotrophic role on the corpus luteum for
maintenance of pregnancy.
PMID- 9764350
TI - Fas-fas ligand system-induced apoptosis in human placenta and gestational
trophoblastic disease.
AB - PROBLEM: The low frequency of maternal immune responses to paternally inherited
fetal antigens raises the following question: What regulates the immunobiology of
pregnancy? Data suggest that this state is the result of peripheral immune
tolerance, an active process of immune-regulation in which activated T cells
undergo apoptosis. We studied Fas ligand (FasL) expression and apoptosis in
normal and pathologic placentas to find out whether the Fas-FasL-induced
apoptosis takes place during implantation. METHOD OF STUDY: FasL expression in
paraffin sections was detected using specific antibodies and confirmed with
reverse transcriptase-polymerase chain reaction of total RNA from frozen
placentas. Apoptosis was detected using the terminal deoxy (d)-UTP nick end
labeling assay. RESULTS: FasL was found in the normal placenta and in gestational
trophoblastic disease. Apoptotic leukocytes were localized to the maternal-fetal
interface corresponding in localization with the distribution of FasL.
CONCLUSIONS: We propose that FasL expression in the placenta is a mechanism
responsible for the development of maternal immune tolerance specific for
paternal alloantigens and operates in pathologic states characterized by
trophoblastic invasion/proliferation.
PMID- 9764351
TI - Placental isoferritin levels in pregnant patients with systemic lupus
erythematosus and/or antiphospholipid syndrome.
AB - PROBLEM: Low serum placental isoferritin (PLF), an immunosuppressive cytokine
like protein, was found in women with underlying placento-vascular dysfunction,
such as intrauterine growth retardation and preeclamptic toxemia. The possible
contribution of this placental product in the assessment of pregnant patients
with either systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome
(APS) was investigated. METHOD OF STUDY: Seventy-five healthy pregnant women used
as controls and 25 preselected pregnant patients with either SLE and/or APS were
enrolled in the study. Study patients were in remission during conception and all
patients agreed to give 5 ml of venous blood at midgestation. The samples were
frozen and analyzed retrospectively. After delivery, pregnancy outcomes were
gathered from hospital records. RESULTS: Seventeen (68%) women had uneventful
pregnancies and deliveries (normal) whereas 8 (32%) showed pathologic obstetric
outcomes. Mean midgestational serum PLF levels were similar in the control and
normal outcome groups (87 U/ml), whereas significantly lower levels (37 U/ml)
were measured in the pathologic outcome group. Using a cutoff level of 10 U/ml,
85% from the normal outcome group and 15% from the pathologic outcome group were
above this threshold level, with 60% specificity and 100% sensitivity.
CONCLUSIONS: These preliminary data suggest that PLF values may reflect placento
vascular functions. These may represent a predictive biomarker for developing
obstetric complications in pregnant women with either SLE and/or APS.
PMID- 9764352
TI - Circulating levels of immunoreactive cytokines in women with preeclampsia.
AB - PROBLEM: Circulating inflammatory cytokines have been implicated in the
pathogenesis of preeclampsia. To test this hypothesis, we measured plasma levels
of immunoreactive tumor necrosis factor (TNF)-alpha and -beta, interleukin (IL)-1
alpha and -beta, and IL-6 and -10 in women with preeclampsia, in women with
transient gestational hypertension, and throughout normal pregnancy. METHOD OF
STUDY: Enzyme-linked immunosorbent assays were used and subjected to extensive
validation studies. RESULTS: The median concentration of plasma TNF-alpha was
increased by twofold in women with preeclampsia compared with that in normal
third-trimester pregnancy (P < 0.001) and in women with gestational hypertension
(P < 0.04). The median concentration of plasma IL-6 was increased by threefold in
women with preeclampsia compared with that in normal third-trimester pregnancy (P
< 0.001) and increased twofold compared with that in women with gestational
hypertension (P < 0.1). There were no significant differences observed in the
levels of plasma IL-1 beta and IL-10 between the preeclamptic and other subject
groups. The level of IL-1 beta, but not the levels of IL-10, TNF-alpha, or IL-6,
was significantly changed during normal pregnancy compared with the nonpregnant
condition manifesting an overall decline (P < 0.04). TNF-beta and IL-1 alpha were
not detected in any samples, possibly because of the low sensitivity of these
particular immunoassays. CONCLUSION: Elevated levels of TNF-alpha and IL-6 may
contribute to the putative endothelial dysfunction of preeclampsia.
PMID- 9764353
TI - Hepatocyte growth factor in human breast milk.
AB - PROBLEM: The purposes of this study were to investigate the presence of
hepatocyte growth factor (HGF) in human milk, to identify the cells that produce
HGF in human milk, and to determine the contribution of HGF to the growth of
neonates. METHOD OF STUDY: The HGF concentrations in serum and whey were
determined with an enzyme-linked immunosorbent assay kit. The presence of HGF in
whey was also examined by Western blot analysis. To determine which cells in
human milk produce HGF, an immunohistochemical examination was conducted. The
expression of HGF mRNA in the mononuclear cells in human milk was examined by
reverse transcriptase-polymerase chain reaction (RT-PCR). The effects of whey and
of recombinant HGF (rHGF) on DNA synthesis by a rat small intestinal cell line,
IEC-6, were examined by [3H]thymidine uptake. RESULTS: Human colostrum whey
contained 2.22 +/- 1.02 ng of HGF/ml. Milk whey collected 1 month later contained
1.83 +/- 1.03 ng of HGF/ml. The presence of the heterodimeric form of HGF in
colostrum whey was demonstrated by Western blot analysis. HGF was detected in the
cytoplasm of human milk macrophages by an immunohistochemical examination, and
the RT-PCR also revealed that HGF mRNA is expressed in the mononuclear cells of
human milk. DNA synthesis by IEC-6 cells was increased by rHGF treatment and by
whey treatment. The effect of whey on DNA synthesis by IEC-6 cells was partially,
but significantly, decreased by anti-human HGF-neutralizing antibody treatment.
CONCLUSIONS: Human milk contains a large amount of the active form of HGF,
produced by macrophages, and HGF in human milk induces the growth of intestinal
cells. Our data suggest that HGF in human milk is one of the important factors
regulating the growth of intestinal cells in neonates after birth.
PMID- 9764354
TI - How might pregnancy immunize against breast cancer?
PMID- 9764355
TI - Immunology understood through pregnancy.
PMID- 9764356
TI - Apoptosis of T cells in the first trimester human decidua.
AB - PROBLEM: Apoptosis has been accepted as a mechanism for maintaining tolerance in
the immune system. The induction of apoptotic cell death can also be a possible
outcome of the lymphocyte activation. Expression of Fas ligand (FasL) by the
human trophoblast has been proposed as a mechanism providing protection against
the lytic action of decidual immune cells. The aim of this study was to determine
whether decidual T cells undergo apoptosis during abortion. METHOD OF STUDY: We
studied apoptosis of T cells isolated from the first-trimester decidua in 12
women after spontaneous or elective abortion. We used gel electrophoresis to
detect DNA fragmentation. Cells undergoing DNA fragmentation also were identified
by DNA analysis using flow cytometry. This method was based on the accumulation
of ethanol-fixed apoptotic cells in the sub-G0/G1 peak of the DNA content as a
result of the loss of DNA fragments from the cells and because of a reduced DNA
ability to be stained by propidium iodide. In addition, the expression of Fas
antigen on the surface of decidual T cells (CD3+) also was determined. RESULTS:
We did not detect apoptosis by the "ladder" technique. However, the apoptotic
index (the percentage of positive cells per total number of cells) ranged from 2%
to 24% using flow cytometry. CONCLUSIONS: Trophoblast cells usually fail to
stimulate alloantigen-specific T cells, but they may express nonclassical major
histocompatibility complex alloantigens to which mothers can produce
immunoglobulin G alloantibody, which requires T helper cell activation. The
apoptosis of T cells in the human decidua, probably through Fas-FasL signaling,
may be a defense mechanism against rejection of the fetal allograft by the
maternal immune system.
PMID- 9764357
TI - Molecular and immunologic aspects of the nonclassical HLA class I antigen HLA-G:
evidence for an important role in the maternal tolerance of the fetal allograft.
AB - PROBLEM: Human leukocyte antigen (HLA)-G is a major histocompatibility complex
class I antigen, which is referred to as nonclassical because it displays a
tissue-restricted distribution in the placenta, a reduced cytoplasmic domain, a
limited polymorphism, and several isoforms. The HLA-G antigen is thought to play
an essential role during pregnancy by protecting the semi-allogeneic fetus from
recognition and destruction by maternal immune cells. METHOD OF STUDY:
Alternative splicing of HLA-G mRNA was analyzed by Southern blot of reverse
transcriptase-polymerase chain reaction products from trophoblasts of the first
trimester of gestation and term placenta. The regulation of HLA-G gene expression
was investigated by electrophoretic mobility shift assays using nuclear extracts
from cells expressing different levels of HLA-G gene activity. Using polymerase
chain reaction-single strand conformational polymorphism and sequencing, we
studied HLA-G gene polymorphism in families from the Centre d'Etude du
Polymorphisme Humain in Paris. To understand the function of the HLA-G molecule,
cytotoxicity assays were carried out with peripheral blood mononuclear cells or
polyclonal natural killer effectors cells from 30 different donors against HLA-G1
and HLA-G2 transfectants. RESULTS: Four main aspects have been elucidated: 1) The
primary transcript of the HLA-G gene is alternatively spliced into five main mRNA
forms: HLA-G1 (full length), HLA-G2 (minus exon 3), which encodes a membrane
bound isoform associated with beta-2 microglobulin, HLA-G3 (minus exons 3 and 4),
HLA-G4 (minus exon 4), and HLA-G5 (plus intron 4), which encodes a soluble form
of the HLA-G antigen; 2) specific nuclear factors bind to an important regulatory
element located more than 1.2 kb from the HLA-G gene. Three specific complexes
are observed in cells that show HLA-G transcriptional activity and an additional
factor that could correlate with the repression of HLA-G gene expression that is
detected in natural killer cells; 3) we observed an important genomic
polymorphism in exon 3 but a very low polymorphism at the protein level; 4) HLA
G1 and HLA-G2 transfectants clearly demonstrated that both HLA-G isoforms are
capable of inhibiting natural killer lytic activity. CONCLUSION: These results
suggest that HLA-G acts as the public ligand for natural killer inhibitory
receptors, thus protecting the fetus against maternal rejection.
PMID- 9764358
TI - HLA-G polymorphisms: ethnic differences and implications for potential molecule
function.
AB - PROBLEM: Human leukocyte antigen (HLA)-G is uniquely expressed on extravillous
cytotrophoblasts of the placenta and is postulated to be a mediator of maternal
immune tolerance. Although it was originally considered to be nonpolymorphic,
variations of the HLA-G DNA sequence have been reported, and a limited number of
HLA-G alleles been defined. METHOD OF STUDY: The HLA-G wild-type sequence was
compared with HLA-A2 with regard to the conservation of functionally essential
parts of classical HLA-I molecules. HLA-G polymorphisms were analyzed under the
aspect of ethnic differences, site, and consequences for postulated molecule
functions. RESULTS: HLA-G exhibits a high degree of conservation relative to HLA
A2 in functionally relevant sites of HLA-class I molecules. However, polymorphic
sites in HLA-G and classical HLA loci are not congruent. CONCLUSION: The type and
localization of HLA-G polymorphisms suggest that different parts of HLA-G
molecule underlie different selective constraints.
PMID- 9764359
TI - Is the expression of classical HLA class I antigens on trophoblast of importance
for human pregnancy?
AB - PROBLEM: Human leukocyte antigen (HLA)-C and possibly also HLA-B seem to be
expressed on the extravillous trophoblast. These antigens carry epitopes that
function as ligands for natural killer (NK)-cell-inhibitory receptors.
Antitrophoblast cytotoxicity mediated by decidual NK cells might be involved in
miscarriage. We thus found it relevant to elucidate whether parental HLA-C and
Bw polymorphism play a role in recurrent miscarriage (RM). METHOD OF STUDY: HLA-C
and -Bw investigations by DNA-based techniques were undertaken in 35 couples with
unexplained RM and in 30 couples with normal fecundity. The number of HLA-C- and
Bw-related supertypic specificities that can bind NK-cell-inhibitory receptors
was evaluated in selected couples. RESULTS: The proportions of couples with RM
and control couples carrying four HLA-C alleles with the same NK-cell-inhibitory
supertypic specificities were equal. In 46% of studied couples with RM, all four
HLA-B alleles carried the HLA-Bw6 supertypic specificity, which was significantly
higher than the corresponding frequency (17%) in the control couples (P < 0.02).
CONCLUSIONS: The expression of polymorphic HLA-C on trophoblasts does not seem to
play a role in RM. Assuming that HLA-B is expressed on trophoblasts, we may
suggest that the revealed predominance of HLA-Bw6 expression (which excludes the
presence of HLA-Bw4-protective antigens) may predispose a particular couple to
the RM phenomenon.
PMID- 9764360
TI - Regulation of major histocompatibility complex and TAP gene products in
preimplantation mouse stage embryos.
AB - PROBLEM: To determine the ontogeny of major histocompatibility complex (MHC)
expression and TAP products in mouse embryos. METHOD OF STUDY: mRNAs encoding MHC
and associated molecules were identified by reverse transcriptase-polymerase
chain reaction, and the protein products were localized by confocal microscopy.
RESULTS: mRNAs encoding class Ia (H-2Db) and class Ib (Q7/9) were present in one
cell embryos, whereas beta 2-microglobulin (beta 2-m) transcripts were not
detected until the two-cell stage. Transporter TAP1, but not TAP2, transcripts
were detected only in blastocysts. H-2 class Ia (classical) protein was detected
on the surface of two-cell embryos, H-2 class Ib (nonclassical) protein was
detected on one-cell embryos, and beta 2-m transcripts were detected on eight
cell embryos; TAP1 protein was present at low levels in the cytoplasm from the
one-cell stage onward, increasing in expression in blastocysts. CONCLUSIONS: In
mice, MHC class I mRNAs encoding the heavy chain of H-2- and Q7/9-encoding Qa2
molecules are synthesized soon after conception prior to implantation. Similarly,
the nonpolymorphic MHC class I-associated molecule beta 2-m also is expressed
before implantation. TAP1, but not TAP2, is first detected at the blastocyst
stage, thus preceding the onset of TAP2 in embryonic development.
PMID- 9764361
TI - Major histocompatibility complex expression on human, male germ cells: a review.
AB - PROBLEM: The male reproductive compartment is an immunologically privileged site.
The expression pattern of human leukocyte antigens (HLAs) may play an important
role in the maintenance of immune tolerance toward differentiating gametogenic
cells. This review presents current knowledge about HLA gene expression on human,
male germ cells, on mRNA and protein levels, and on their methylation status.
METHOD OF STUDY: Different techniques were applied to study HLA gene expression
in human testis: (a) protein: e.g., cytotoxicity test, fluorescent labeling
techniques, enzyme-linked immunosorbent assay, and confocal microscopy; (b) mRNA:
reverse transcriptase-polymerase chain reaction, Northern blot hybridization, and
in situ hybridization; and (c) methylation status. RESULTS: In normal testicular
tissue we observe a lack of HLA-class I (classical) antigens expression and
inversely related expression pattern of HLA class I classical and nonclassical
genes. HLA-A, -B, -C, and -E loci are likewise methylated in somatic and germ
cells, whereas -F and -G genes are less methylated in sperm precursors.
CONCLUSIONS: Immunologic tolerance in human testis is actively maintained by the
specific expression pattern of HLA genes regulated by hormones and growth
factors.
PMID- 9764362
TI - Unique biochemical properties of human leukocyte antigen-E allow for a highly
specific function in immune recognition.
AB - PROBLEM: Does a correlation exist between the expression of human leukocyte
antigen (HLA) class Ia and HLA-E and what is its biological significance? METHOD
OF STUDY: HLA-E transcripts were detected by reverse transcriptase-polymerase
chain reaction. Metabolically labeled HLA-E heavy chains were immunoprecipited
and analyzed by one-dimensional isoelectric focusing. Mouse RMA-S cells defective
with regard to transporter associated with antigen processing (TAP) function were
transfected with HLA-E and human beta 2-microglobulin to investigate TAP
dependence of the cell-surface expression of HLA-E. RESULTS: HLA-E is transcribed
regardless of the down-regulation of polymorphic HLA class Ia expression. HLA-E
is transported to the cell surface in the absence of TAP-controlled peptide
loading. In human cells, the amount of HLA-E protein is very low regardless of
the presence of correct peptide ligands. CONCLUSIONS: HLA-E regulates immune
functions in cells that have down-regulated the expression of polymorphic HLA
class Ia molecules, either by preventing harmful natural killer cells from
attacking targets that have physiologically decreased HLA-class Ia expression or
by activating effector cells against virus-infected and tumor cells with impaired
HLA-class Ia expression.
PMID- 9764363
TI - Sexual and mother-to-child transmission of the human immunodeficiency virus type
1: a review.
AB - PROBLEM: Sexual and mother-to-child transmission of the human immunodeficiency
virus (HIV) type 1 occurs only with a low percentage of infection. Many instances
of sexual intercourse result in no transmission, and only 20% of children are
infected from seropositive mothers (3% in mothers treated with azidothymidine).
METHOD OF STUDY: We analyzed the presence of HIV in various ejaculates of the
same HIV-infected patients, as well as in the cervico-vaginal fluid. We have
studied the mechanism of transmission from mother to child, by analyzing the cell
to-cell transmission in the trophoblast. RESULTS: Some ejaculates collected at
different times from the same HIV-infected males are free of virus, explaining
the low rate of sexual transmission. We never found HIV in mobile spermatozoa.
The trophoblast can be infected by HIV with a strain dependence and also
transiently. By analyzing the tissue of the fetus, it was found that only some
organs are infected, confirming the cell-to-cell transmission between the mother
and child and not a true vertical transmission through the germinal lines.
CONCLUSIONS: HIV is not always present in the genital secretion, explaining the
low rate of sexual transmission. Mother-to-child transmission occurs during
pregnancy but often after the second trimester and at delivery after cell-to-cell
or blood transmission, respectively.
PMID- 9764364
TI - Fertility-disrupting potential of synthetic peptides derived from the beta
subunit of follicle-stimulating hormone.
AB - PROBLEM: Hormone immunoneutralization is hampered by immunologic cross-reactivity
caused by close-sequence homology between related molecules. One solution is to
use smaller fragments to induce antibodies of greater specificity. METHOD OF
STUDY: A number of peptides selected from beta-follicle-stimulating hormone (FSH)
were conjugated to tetanus toxoid and were used to immunize female rats. The
antisera were examined for FSH cross-reactivity by immunoassays and in an in
vitro bioassay. RESULTS: In the immunoassays, the antisera did not react with FSH
but did react with their respective peptides. In the bioassay, sera from
VYKDPARPC- and CDSLYTYP-immunized animals inhibited FSH-receptor interaction by
73% and 68%, respectively. These animals also showed reduced estradiol levels.
Sequences were synthesized around VYKDPARPC and were tested on a FSH-receptor
bearing Chinese hamster ovary cell line. LVYKDPARPC, VYKDPARPC, YKDPARPIC,
CLVYKDPARP, and LVYKDPARP inhibited FSH-receptor interaction by greater than 50%.
In female mice, TRDLVYKDPARPKI and LVYKDPARP disrupted estrous cycling in all
animals; LVYKDPARPC and CLVYKDPARP disrupted cycling in three of five animals,
whereas VYKDPARPC disrupted cycling in one of four animals. CONCLUSIONS: Peptides
from two areas of beta-FSH (VYKDPARP and DSLYTYP) were shown to raise FSH
neutralizing antibodies, which were able to suppress estradiol levels. An
additional leucine residue to VYKDPARP greatly enhanced the peptide's ability to
inhibit FSH-receptor binding and caused fertility disruption in vivo.
PMID- 9764365
TI - Evaluation of the contraceptive potential of recombinant human ZP3 and human ZP3
peptides in a primate model: their safety and efficacy.
AB - PROBLEM: The unique recognition events that result in the avid binding of
mammalian spermatozoa to the surface of the zona pellucida (ZP) are being
exploited in the development of contraceptive vaccines. In this study, the safety
and efficacy of a vaccination strategy based on the induction of active immunity
against purified, glycosylated, recombinant human ZP3 (rhZP3) has been evaluated
in a primate model, Callithrix jacchus. METHOD OF STUDY: Long-term infertility
was established after immunization with rhZP3 and the resulting immune sera
reacted with rhZP3 on an enzyme-linked immunosorbent assay (ELISA) and
immunolocalized exclusively to the outer surface of native ZP on marmoset ovarian
sections. However, this contraceptive effect was inevitably associated with the
eventual appearance of an ovarian pathology characterized by a depletion of
primordial follicles. In an attempt to circumvent this side effect, human ZP3
(hZP3) was epitope mapped and four continuous, immunodominant B-cell epitopes
(hZP3(45-64), hZP3(93-110), hZP3(172-190) and hZP3(341-360) were evaluated for
contraceptive efficacy in vivo. Using peptide-tetanus toxoid (TT) conjugates to
enhance immunogenicity, antipeptide antibodies were raised against these
immunogens, which also cross-reacted with rhZP3 on ELISA. In addition, antibodies
against hZP3(45-64) and hZP3(172-190) recognized native ZP on marmoset ovarian
sections when a microwave technique was used to enhance epitope presentation.
RESULTS: No ovarian pathology was observed after the long-term administration of
these peptide immunogens, and fertility was suppressed when compared with TT
controls but could not be correlated to the antibody titer. CONCLUSION: Clearly,
further research is required to identify optimal B-cell epitopes that will
reliably induce infertility, free from any ovarian pathology.
PMID- 9764366
TI - Epitopes of human chorionic gonadotropin and their relationship to immunogenicity
and cross-reactivity of beta-chain mutants.
AB - PROBLEM: Human chrionic gonadotropin (hCG) is a placental glycoprotein hormone, a
heterodimeric molecule, consisting of alpha and beta chains. It induces the
synthesis of progesterone, which is essential for the maintenance of the
fertilized egg. Antibodies directed against hCG can, therefore, prevent pregnancy
and serve as a vaccine. hCG belongs to the glycoprotein hormone family and shares
the alpha chain with the other members. The beta chain is a hormone-specific
subunit that is unique to hCG, but still possesses 85% amino acid homology with
the beta chain of luteinizing hormone (LH), which means that prolonged
immunization with hCG produces antibodies that cross-react with LH. METHOD OF
STUDY: We have taken an approach involving the mutation of beta hCG to eliminate
cross-reactive epitopes without affecting the natural folding of the polypeptide
chain and thus the unique beta hCG-specific epitopes. RESULTS: Several mutants
have been constructed that have maintained the binding to hCG-specific monoclonal
antibodies (mAbs) but have lost the ability to bind to a panel of LH cross
reactive mAbs. To investigate the immunogenicity of selected mutants, mice were
immunized with expression plasmid DNA, containing the gene for wild-type beta hCG
and two mutants: mutant 3, with four amino acid substitutions (68 Arg-->Glu; 74
Arg-->Ser; 75 Gly-->His; 79 Val-->His), and mutant 7, with a single amino acid
substitution (68 Arg-->Glu). CONCLUSIONS: Although both mutants were able to
elicit antibody responses in at least some animals, the levels were less than
those seen with the wild-type beta hCG DNA, and there seems still to be a
residual cross-reactivity with LH. Attempts to improve the immunogenicity of the
mutants and to further modify the sequence to remove the cross-reactivity are
currently underway.
PMID- 9764367
TI - Do autoantibodies to sperm reduce fecundity? A mini-review in historical
perspective.
AB - PROBLEM: The paradox that early studies of antisperm antibodies in men showed a
strong correlation between titers of circulating antibodies (essentially
immunoglobulin [Ig] G) and reduction in conception rates, whereas more recent
studies have indicated that the antifertility effect is mainly (or exclusively?)
associated with IgA antibodies, impairing sperm migration through cervical mucus,
was studied. METHOD OF STUDY: Relevant literature focusing on antibodies on
ejaculated sperm was analyzed. RESULTS: Direct mixed antiglobulin reaction (MAR)
and immunobead-binding tests are excellent and sensitive techniques for
demonstrating antibodies of the IgG and IgA classes on sperm, and they have
revealed that IgA antibodies are, with very rare exceptions, found only when IgG
antibodies are also present. However, these tests tell little about the amounts
of antibodies present, and attempts to measure quantitatively the amounts of Ig
on sperm have indicated higher levels of IgA than IgG (despite the strongest MAR
reactivities for IgG). CONCLUSIONS: The patients with high levels of IgA to their
sperm are mainly men with strong immune responses and, therefore, also high
antibody titers in serum. Apparently, the locally produced IgA antibodies reach
the sperm and occupy the binding sites before the main bulk of IgG reaches the
seminal compartment with the prostatic fluid.
PMID- 9764368
TI - Antisperm antibodies in prepubertal boys and their reactivity with antigenic
determinants on differentiated spermatozoa.
AB - PROBLEM: Antisperm antibodies induced in prepubertal boys with testicular
failures were characterized by using four techniques of antibody detection. The
reactivity of circulating antisperm antibodies in prepubertal boys and the
reactivity of antibodies in sera samples of adult fertile and infertile males
were compared against the same sperm antigenic pools (live or fixed spermatozoa,
or sperm antigenic extracts). METHOD OF STUDY: The incidence of antisperm
antibodies in sera samples of 69 prepubertal boys with testicular failures and 21
samples obtained from adult, male individuals was assessed by indirect immunobead
binding test (IDIBT), flow cytometry measurement, enzyme-linked immunosorbent
assay, and Western blotting. Immunoblot analysis was performed by using sperm
extracts of glycosylated and deglycosylated solubilized membrane antigens.
RESULTS: Sera samples were studied in a group composed of healthy prepubertal
boys (n = 7) and prepubertal boys with testicular failures (n = 69). Applied
tests of antibody detection revealed striking differences in a group of boys with
testicular pathology. With IDIBT, 7% of the sera samples were found positive,
whereas with flow cytometry measurement, 48% of the sera samples were positive.
Immunosorbent assay (fixed sperm) indicated 32% positive cases in the same group.
The sera samples were found to be positive in 65% of immunoblotting reactions
with glycosylated antigens and in 70% of immunoblotting reactions with
deglycosylated antigens. All applied detection assays were clearly negative on
sera samples from fertile, adult males. Western immunoblotting indicated an
immunodominant antigenic determinant of 58 kDa. CONCLUSIONS: Tests of antibody
detection with the use of live sperm (IDIBT and flow cytometry measurements)
presented low sensitivity (8% and 48%, respectively) in a group of prepubertal
boys. This observation underlines the difficulties in assigning the prospective
prognosis of future fertility status in prepubertal boys with antisperm
antibodies.
PMID- 9764369
TI - The 4 Rs of clinical excellence.
PMID- 9764370
TI - A question of quality: radiotherapy resources and waiting time outcomes for
cancer patients.
PMID- 9764371
TI - The BNLI: past and present. British National Lymphoma Investigation.
PMID- 9764372
TI - Cancer in developing countries: Part I--Cancer burden, resources, epidemiology,
aetiology and clinical practice.
PMID- 9764373
TI - Dosimetry rules for brachytherapy using high dose rate remote afterloading
implants.
AB - The increasing availability of high dose rate (HDR) afterloading units has
highlighted the potential use of this form of brachytherapy in an ever wider
number of clinical sites. Alongside this, commercial planning systems for
brachytherapy offer almost infinite possibilities for the differential loading of
applicators in an attempt to produce an ideal dose distribution. Dosimetry in the
UK has been based largely on the Manchester and Paris systems; modifications and
optimization of the Paris system in HDR brachytherapy have been proposed, but the
Manchester dosimetry system, with its emphasis on dose homogeneity throughout the
specified treatment plane or specified treatment volume, can also be successfully
applied, unmodified, in HDR dosimetry. A comparison of Manchester, Paris and
optimized distributions for an HDR implant is presented, illustrating how
subjectively and on the basis of dose-volume histograms, optimization has in this
clinical case failed to improve on the uniformity of the Manchester rules
distribution. It is proposed that optimization systems should have an option to
apply these rules with further individualized clinical optimization if required.
This would permit uniform reporting of implant parameters where, by describing
the clinical target volume, the total reference air kerma and initial
distribution of dwell times will be defined.
PMID- 9764374
TI - Technical hints for high dose rate interstitial tongue brachytherapy.
AB - High dose rate (HDR) interstitial tongue brachytherapy is a new treatment
modality. This study describes important technical details required for its
successful use. Thirteen patients with carcinoma of the oral tongue were treated
solely with interstitial brachytherapy using HDR remote afterloading techniques
during the years 1994-1997. The afterloading catheters were positioned by the
submandibular approach with the assistance of a template set. Custom-made
mandibular lead shields were inserted prior to treatment. Special reusable Tuen
Mun Hospital (TMH) lead buttons were made for improved radiation protection. The
median dose given was 55 Gy in ten fractions over 6 days. The interfraction
interval was 7 hours for the first seven patients treated and was extended to 8
hours for the other six. Shrinking field techniques were employed and the
treatment length of the last fraction was reduced by 5 mm. Commencing with the
second patient treated with double planar implants, the medial plane was treated
with eight fractions while the lateral plane received ten fractions. To reduce
further the potential risk of tract seeding, additional coverage to the
implantation tracts was given for the last four patients, with the resultant
isodose curves resembling a 'comb rake/brush'. The mean and median measured doses
on the inner face of the mandibular shields were 113% and 93% of the reference
dose respectively (range 77-247). The dose to the corresponding sites on the
gingival surface can be reduced by 75% if the 3 mm thick lead shield is placed
successfully. With the use of the TMH button, the transmitted dose to the tissue
in direct contact can be reduced by one-third. With the 'comb rake/brush' dose
distribution, the high dose volume of the single planar implants could be reduced
by 44%, compared with the low dose rate technique, if loading to just 5 mm short
of the submandibular skin was required. The mean doses for the combination of
eight double planar plus two single planar implants, and ten double planar
implants, are on average 29% and 37% greater than the reference dose
respectively. An 8% reduction in absolute dose in the region between the planes
of the catheters would lead to an even greater magnitude of reduction in
morbidity to late responding tissue. The prerequisite for the success of HDR
interstitial implants is to develop a good technique in positioning the
afterloading catheters and protection of the normal tissue. Its importance merits
special attention if HDR remote afterloading interstitial tongue brachytherapy is
to realize its full potential.
PMID- 9764375
TI - The management and clinical course of testicular seminoma: 15 years' experience
at a single institution.
AB - Testicular seminoma is one of the most curable solid neoplasms, with 5-year
survival rates in excess of 90%. However, controversy persists around its optimum
management, particularly for Stage I disease. The outcome of 314 patients with
testicular seminoma who were treated at a single institution is reported. A
comparison of adjuvant radiotherapy and surveillance for Stage I is presented,
and the possible prognostic influence of an elevated serum beta-human chorionic
gonadotrophin (beta hCG) is assessed. The 5-year disease-free survival for all
stages of presentation was 95.5%. There were more relapses in Stage I patients
undergoing surveillance (14/94, 15%) than postorchidectomy radiotherapy (6/144,
4%; P = < 0.05). However, survival was identical irrespective of treatment
policy, with no disease-related deaths in either group of Stage I patients. There
were eight tumour-related deaths from advanced disease and 14 deaths from non
tumour causes. Three were due to cardiorespiratory disease, four to an unrelated
second malignancy, two from infection and one from suicide; in four patients, the
cause was unknown. Preoperative beta hCG was elevated in 29 (18%) of Stage I
patients and in 24 (62%) of those presenting with Stage II disease. Patients were
more likely to have advanced disease (> or = Stage II) if beta hCG was elevated
(P < 0.001). Neither disease-free nor overall survival were influenced by the
preoperative level of beta hCG. Surveillance appears to be a safe alternative to
postorchidectomy radiotherapy for Stage I disease, provided the patient is
prepared for intensive long term follow-up. An increased risk of relapse, but not
of tumour death, can be expected and unnecessary treatments avoided.
PMID- 9764376
TI - Granulosa cell tumours of the ovary: demographics, survival and the management of
advanced disease.
AB - Ovarian granulosa cell tumours (OGCT) are rare, accounting for only 3%-5% of
primary ovarian tumours. As a result of oestrogen production OGCTs tend to
present with early stage disease, which has a good prognosis. For patients with
advanced disease, surgery and radiotherapy have been the major modalities of
treatment. More recently, platinum-based chemotherapy has been shown to have
important activity in advanced disease. In this retrospective study, we have
reviewed the results of 62 patients who were treated for adult OGCT at the Royal
Marsden Hospital between 1969 and 1995, with particular emphasis on the
management of advanced disease. The median age at primary diagnosis was 53 years
(range 13-77). Sixty-one per cent of these patients had Stage I disease, 21%
Stage II disease, 16% Stage III and 2% Stage IV. Stage I patients had a good
prognosis with 5- and 10-year overall survival rates of 95% and 90%. Eleven Stage
I patients received adjuvant pelvic radiotherapy, with no apparent benefit to
recurrent rate or overall survival. Disease progression occurred in 40% of Stage
I patients at a median interval of 76 months (range 12-240), and in 62% of the
Stage II patients, at a median interval of 31 months (range 2-57). The median
interval from progression of Stage I/II disease to death was 22 months (range 3
144). For patients with inoperable disease, radiotherapy produced a number of
long-term remissions with an overall response rate of 50%. Platinum-based
chemotherapy also appears active, with responses documented in four out of five
patients treated with the PVB regimen (cisplatin, vinblastine, bleomycin) as
first line therapy. There were no responses documented to non-platinum
chemotherapy or to hormonal manipulation. The results from this study confirm the
activity of platinum-containing chemotherapy regimens in OGCT and support the
need for further trials to optimize the management of this rare tumour.
PMID- 9764377
TI - Malignant mixed mullerian tumours of gynaecological origin: chemosensitive but
aggressive tumours.
AB - We report the clinical management and outcome of 11 patients with a histological
diagnosis of mixed mullerian tumour of gynaecological origin who were treated at
Weston Park Hospital, Sheffield during the period 1991 to 1996. Case note review
provided the data on the patients, their disease and the treatment given. In six
patients, the primary site was the ovary and in four it was the uterus; in the
remaining patient, the tissue of primary origin was uncertain. The median age at
diagnosis was 53 years (range 48-84). Seven patients had heterologous tumour
histology. All but one underwent surgical removal or debulking of disease. Seven
patients were treated with platinum-based chemotherapy. There were four complete
responders and three partial responders. The median survival was 18 months. Three
patients remain alive, two of them disease-free. Mixed mullerian tumours are
initially chemosensitive but have an aggressive clinical course, typically with
early relapse after treatment and a poor long-term prognosis. Collaborative Phase
III studies are required to improve the management of this uncommon cancer.
PMID- 9764378
TI - Somnolence syndrome in adults following cranial irradiation for primary brain
tumours.
AB - The purpose of this study was to assess the incidence, pattern and severity of
somnolence and fatigue in patients treated with cranial irradiation for primary
brain tumours and to identify factors that may influence or mediate symptoms. A
detailed prospective study was carried out of 19 patients who received high-dose
(45-55 Gy) cranial irradiation as treatment for primary brain tumours. Data were
collected for each patient over a 3 month period using a prospective diary
utilizing visual analogue scales of common somnolence symptoms and fatigue, and
detailed interviews at 2, 6 and 12 weeks following the completion of treatment.
Sixteen patients developed somnolence syndrome following treatment. Time series
analysis identified a cyclical pattern to the symptoms, with a period of
drowsiness and fatigue occurring from day 11 to day 21 and from day 31 to day 35
after radiotherapy. The principal symptoms were those of excessive drowsiness,
feeling clumsy, an inability to concentrate, lethargy, being mentally slow and
fatigue. Patients treated with accelerated (n = 11) compared with more
conventional (n = 8) fractionation experienced more severe drowsiness and fatigue
(P < 0.01), although there was no difference in the pattern or the incidence of
symptoms. Interview data suggested that patients frequently attributed their
symptoms of somnolence to 'flu or other ailments. The unexplained and
overwhelming nature of the symptoms was a cause of anxiety. The prospective
assessment of symptoms following radiotherapy highlighted a more detailed
definition of the symptom complex and pattern of occurrence. Somnolence syndrome
is a collection of symptoms consisting of drowsiness, lethargy and fatigue.
Forewarning patients and planning supportive management around times of
drowsiness and fatigue can help to reduce the anxiety that these symptoms cause.
PMID- 9764379
TI - The importance of cytogenetics and associated molecular techniques in the
management of patients with leukaemia.
AB - The cytogenetic analysis of haematological malignancies plays a major role in
diagnosis. A large number of non-random chromosomal abnormalities are associated
with specific types of leukaemia. Often, the cytogenetic result provides the
definitive diagnosis. The recent developments in molecular cytogenetic
technologies, in association with conventional cytogenetic analysis, have
improved the accuracy of the results and led to the finding of new chromosomal
abnormalities in leukaemia. Patients may be monitored by cytogenetics, molecular
techniques and/or fluorescence in situ hybridization (FISH) during the course of
their management, for evidence of minimal residual disease. These techniques also
provide a useful method for monitoring patients following bone marrow
transplantation, particularly when the patient and the donor are of the opposite
sex. The cytogenetic result is an independent prognostic indicator, with certain
karyotypes associated with a good prognosis, although others indicate a poor
outcome.
PMID- 9764380
TI - An audit and evaluation of bladder movements during radical radiotherapy.
AB - With the introduction of the conformal approach for radical radiotherapy for
prostate cancer, there has been renewed interest in the movement of the prostate
and other pelvic organs during the course of radical pelvic radiotherapy. Many
patients reviewed during a course of radical radiotherapy for bladder carcinoma
have urinary flow symptoms, which may suggest impaired bladder emptying. There is
concern, therefore, that the bladder volume may increase during such treatment,
leading to inadequate coverage of the bladder by the planning target volume. We
used serial CT scans to assess bladder size in 20 patients during the course of
radical bladder radiotherapy. Our results showed that there was little variation
in the left to right direction and, in 12 of the 20 patients studied, the
anteriorposterior (AP) movement was < 1 cm. The bladder dome rose out of the
treatment field in two patients during the course of therapy. However, in 16
patients, the target volume was encompassed as planned throughout.
PMID- 9764381
TI - Low grade MALT lymphoma of the urinary bladder.
AB - Primary lymphoma of the bladder is rare. Of the very few cases reported, most
appear to be of low grade with a generally good prognosis. Since the concept of
low grade lymphoma of mucosa associated lymphoid tissue (also known as marginal
zone lymphoma in the REAL classification) was introduced, only six examples of
this entity have been recorded at this site. We present a further case and
describe its phenotypic characterization.
PMID- 9764382
TI - Death due to thyroid metastases from renal cell carcinoma.
AB - Renal cell carcinoma is a tumour that is well recognized to metastasize widely
and to behave in an unpredictable manner. We report a patient with a renal cell
carcinoma that metastasized to the thyroid and resulted in death from associated
respiratory compromise. The clinical features of cancers metastasizing to the
thyroid are discussed and the apparent over-representation of renal cell
carcinoma in symptomatic thyroid metastases is highlighted. The uncertainty about
whether metastases arise more frequently in pre-existing abnormal thyroid glands
is also reviewed.
PMID- 9764383
TI - Severe hypertriglyceridaemia and hypercholesterolaemia associated with tamoxifen
use.
AB - A patient who was given tamoxifen as adjuvant treatment for breast cancer
developed very severe hypertriglyceridaemia, hypercholesterolaemia and acute
pancreatitis after being treated for 4 months. The hyperlipidaemia was corrected
after cessation of the tamoxifen and the institution of gemfibrozil treatment.
This patient appears to have type IV hyperlipidaemia. It is suggested that, in
such patients, tamoxifen should be used with extreme caution because the weakly
oestrogenic effect of this agent can cause severe and life threatening
hyperlipidaemia.
PMID- 9764384
TI - Massive lethal cerebral bleeding in a patient with melanoma without intracranial
metastasis.
AB - The case history is reported of a patient with melanoma and advanced metastases,
who died from massive cerebral bleeding. The lethal event was not caused by
intracerebral metastasis but by thrombocytopenia. Depression of the bone marrow
resulted from tumour infiltration of the skeleton, chemotherapy and vertebral
irradiation. An increase of intracranial pressure triggered the cerebral
bleeding, caused by haematemesis from a gastric metastasis directly preceding
sudden somnolence.
PMID- 9764385
TI - Acute stroke following cisplatin therapy.
AB - Cisplatin is a very effective drug in modern chemotherapy practice. It has many
side effects, including neurotoxicity, and has been tentatively implicated in
acute stroke. We describe a 21-year-old woman who presented with an acute stroke,
confirmed on MRI as a cerebral infarction.
PMID- 9764386
TI - Second opinions in oncology: nuisance or opportunity?
PMID- 9764387
TI - Detection of enterotoxigenic Escherichia coli in stool specimens by polymerase
chain reaction.
AB - A polymerase chain reaction (PCR) protocol for rapid (7 h) detection of
enterotoxigenic Escherichia coli (ETEC) is described. This protocol has been
validated on 57 stool samples from young children by comparing it with the colony
hybridization technique. A good agreement was found between the two methods with
Cohen's kappa statistics of 0.87 and 0.79 for the detection of the heat-stable
toxin (ST) and heat-labile toxin (LT), respectively. Of 26 samples positive for
LT and 15 samples positive for ST by colony hybridization, 21 (81%) and 15 (100%)
were also found to be positive for LT and ST by PCR, respectively. Only one
sample identified as LT-negative by colony hybridization was found to be positive
by PCR. However, 3 of 42 samples of ST-negative by colony hybridization were
detected as positive by PCR. A reconstruction experiment revealed that PCR could
detect LT-producing and ST-producing ETEC at minimal concentrations of 2.5 x
10(3) cfu and 2.5 x 10(2) cfu per gram of feces, respectively. These data
indicate the possible use of this method for rapid identification of ETEC
associated diarrhea in clinical and epidemiological settings.
PMID- 9764388
TI - Molecular epidemiology of penicillin-resistant Streptococcus pneumoniae isolated
in central Taiwan.
AB - Previous studies have suggested that penicillin-resistant pneumococcal isolates
(especially those with MIC > 1 microgram/mL) usually are clonally related. To
test this hypothesis, the molecular epidemiology of 29 clinical isolates of
penicillin-resistant pneumococci (of which 83% were also resistant to either
cefotaxime or ceftriaxone) collected in central Taiwan was investigated by pulsed
field gel electrophoresis. Twenty-seven distinct patterns were identified. Our
results indicate that an increase in penicillin-resistant S. pneumoniae between
April 1993 and June 1994 in central Taiwan is not due to the clonal dissemination
of a limited number of epidemic strains.
PMID- 9764389
TI - The rationale and method for constructing internal control DNA used in pertussis
polymerase chain reaction.
AB - The inclusion of an appropriate internal control DNA in polymerase chain reaction
(PCR) is a rapid and simple method for the detection of PCR failure. Two PCR
coamplification internal control DNAs (ICD I and ICD II) with the same primer
binding sequences as the target DNA for the detection of Bordetella pertussis and
Bordetella parapertussis were produced using an overlap extension technique and a
PCR MIMIC construction kit, respectively. The ICD II was further evaluated in a
prospective clinical study in 360 patients with a clinical diagnosis of
pertussis. From 360 nasopharyngeal swabs the internal control was positive in 318
(88%) samples, but was negative in 42 (12%). After phenol-chloroform extraction
an additional 10 internal controls became positive. For the detection of PCR
failure, the use of internal control DNA is highly recommended for PCR-based
identification of B. pertussis and B. parapertussis organisms from nasopharyngeal
swabs and aspirates.
PMID- 9764390
TI - Colonization and microbiology of the motile enterococci in a patient population.
AB - The motile enterococci with the vanC gene have intrinsic low-level resistance to
vancomycin, but have not been implicated in a nosocomial outbreak. We determined
the colonization rate of motile enterococci in hospitalized and nonhospitalized
patients. Perianal or stool specimens were cultured in Enterococcosel broth
supplemented with 6 micrograms of vancomycin per mL. Rapid motility and pigment
tests were performed on all enterococci isolated. A total of 82 motile and/or
pigmented enterococci were isolated from 679 patients for a colonization rate of
12.1%. There were 43 Enterococcus gallinarum, 32 Enterococcus casseliflavus, 4
Enterococcus flavescens, and 3 Enterococcus mundtii identified. The E. gallinarum
vancomycin MIC90 was 32 micrograms/mL and the E. casseliflavus vancomycin MIC90
was 8 micrograms/mL.
PMID- 9764391
TI - Detection and characterization of Helicobacter pylori from patients with
gastroduodenal diseases.
AB - Polymerase chain reaction and cytotoxin assays were performed to identify as
Helicobacter pylori type I (cagA+/tox+) or type II (cagA-/tox-) 56 (59.6%)
strains from 94 patients. Of these patients 64 were affected by nonulcer
dyspepsia (NUD), 10 by gastric ulcer (GU), 19 by duodenal ulcer (DU), and 1 by
both GU and DU. H. pylori strains were tested for cagA using two sets of primers;
target sequences were detected in 40-42/56 (71.4-75%) depending on the set of
primers used, while cytotoxin-producing strains (tox +) were 26/56 (46.4%). Tox+
strains were isolated in 13/32 (40.6%), 2/7 (28.6%), and 11/17 (64.7%) in NUD,
GU, and DU patients, respectively. However, the different percentage between
cagA+ strains from NUD patients (13/32; 40.6%) and patients with ulcerative
diseases (13/23; 54.2%) is not statistically significant (p = 0.462). Because the
two sets of primers employed for amplification of cagA target sequences give
different results, we concluded that cagA alone could not be taken as predictive
factor for severity of gastroduodenal disease. It has been found that H. pylori
type I is associated with duodenal ulcer disease.
PMID- 9764392
TI - Comparison of algorithms for selective use of nucleic-acid probes for
identification of Mycobacterium tuberculosis from BACTEC 12B bottles.
AB - We retrospectively compared the sensitivity of two approaches, a time-to
detection algorithm and the presence of serpentine cords of acid-fast bacilli,
for discriminating between BACTEC 12B cultures containing either Mycobacterium
tuberculosis complex (MTB) or Mycobacterium avium complex (MAC). From January
1996 through March 1997 a total of 217 of 2089 respiratory specimens received in
our laboratory were positive in the BACTEC 12B radiometric culture system for
either MTB (120 specimens) or MAC (97 specimens). Use of a previously published
time-to-positivity algorithm would have resulted in the correct use of the MTB
probe on 109 of 120 cultures (91% sensitivity), and the MAC probe on 52 of 97
cultures (54% sensitivity). The presence of serpentine cords was detected in 58
of 120 cultures containing MTB (48%), and in 3 of 97 (3%) cultures containing
MAC. Using a combination of time to positivity and cord formation to determine
initial probe selection would have resulted in first use of the MTB probe in 116
of 120 (97%) instances in which MTB was present in the culture. In only 49 of 97
(51%) cultures, however, from which MAC was recovered would the correct probe
have been selected. These results indicate that limiting the initial use of the
MTB probe to those cultures that are either identified by the time-to-detection
algorithm or demonstrate serpentine cords on acid-fast smear would eliminate a
considerable amount of unnecessary probe use without compromising the efficiency
of identification of isolates of MTB.
PMID- 9764393
TI - Multisite reproducibility of MIC results by the Sensititre YeastOne colorimetric
antifungal susceptibility panel.
AB - Reproducibility of MIC results between laboratories, a major performance
criterion used for evaluation of any susceptibility test method, was determined
at three test sites using the Sensititre YeastOne Antifungal Panel, which
incorporates Alamar Blue as a colorimetric indicator. MICs of five antifungals
were determined using a set of 10 isolates of Candida species. Each isolate was
tested a total of nine times against each antifungal agent in each of the three
laboratories. A total of 1350 MICs were evaluated. MICs were read visually after
incubation at 35 degrees C for 24 and 48 h. Overall, 99 to 100% of MIC values
were encompassed by a range defined by the modal MIC +/- 1 dilution for each
antifungal agent tested at both 24 h and 48 h. Replicate testing of the quality
control isolates recommended by the National Committee for Clinical Laboratory
Standards demonstrated excellent agreement between results obtained with the
Sensititre YeastOne panel and the MIC reference range for each antifungal agent.
These studies demonstrated that the Sensititre YeastOne Antifungal Panel may be
used to generate MIC values for at least five different antifungal agents with a
high degree of intra- and interlaboratory reproducibility.
PMID- 9764394
TI - Detection of Epstein-Barr virus-specific antibodies by an automated enzyme
immunoassay. Performance evaluation and cost analysis.
AB - Detection of antibodies to specific antigens of Epstein-Barr virus (EBV) has been
conventionally performed by an immunofluorescence assay (IFA). The procedure is
labor intensive and expensive, and interpretation of results is subjective. We
evaluated an automated enzyme immunoassay (EIA) (INC-STAR Corp., Stillwater, MN,
USA) using 290 serum specimens submitted for the diagnosis of acute infection
with EBV. Antibodies (IgG, IgM) to EBV capsid antigen and IgG class antibodies to
the nuclear antigen of the virus were obtained using the LABOTECH Automated
Microplate Analyzer (BioChem ImmunoSystems Inc., Allentown, PA, USA) and were
compared to the antibody profile results obtained by IFA and Western blot as the
"gold standard." For detection of acute infection with EBV (presence of IgM and
IgG antibodies to the capsid antigen; absence of antibodies to the nuclear
antigen), the EIA had 100% sensitivity (11 of 11) and 99% specificity (275 of
279) compared to IFA and Western blot results. A cost analysis of IFA and EIA
procedures, based on an estimated annual volume of 12,000 procedures, indicated
that $236,000 direct cost and 1,400 h technologist time could be saved with the
automated compared with immunofluorescence procedure. The automated EIA for
determination of antibodies provides cost-effective, accurate diagnosis of EBV
infections in laboratories processing high numbers of specimens now processed by
IFA.
PMID- 9764395
TI - Enhancement of varicella-zoster virus detection in A-549 shell vials by use of
freeze-thawed specimens, extended incubation, and "a centrifuged, not incubated"
direct detection method.
AB - A total of 95 clinical samples were cultured for periods of 2 and 7 days in
centrifuged A-549 shell vials before and after freezing and thawing of specimens.
In addition, centrifuged A-549 shell vials were tested directly for varicella
zoster virus without incubation using a direct fluorescent antibody (DFA)
technique. Twenty-seven specimens were positive by at least one method. The
sensitivity for DFA on unincubated A-549 shell vials was 85.2%; for unfrozen 2
day cultures, 88.9%; for unfrozen 7-day cultures, 92.6%; for freeze-thaw 2-day
cultures, 92.6%; and for freeze-thaw 7-day cultures, 96.3%. Freeze-thawed
specimens cultured for 7 days yielded the highest number of positive results with
conspicuous cell-to-cell spread as a sign of viral replication.
PMID- 9764396
TI - Emphysematous prostatic abscess due to Klebsiella pneumoniae.
AB - Prostatic abscess is an unusual occurrence in the era of modern antibiotics. We
report a rare case of emphysematous prostatic abscess owing to Klebsiella
pneumoniae in a 45-year-old man with a 10-year history of alcoholism and a 6-year
history of diabetes mellitus. Prostatic abscess is a difficult clinical diagnosis
without specific symptoms and signs. Computerized tomography can assist in making
the diagnosis of emphysematous prostatic abscess. Definitive treatment is
complete surgical drainage and the use of effective antibiotics.
PMID- 9764397
TI - European Glycopeptide Susceptibility Survey of gram-positive bacteria for 1995.
European Glycopeptide Resistance Survey Study Group.
AB - In the European Glycopeptide Susceptibility Survey 7078 Gram-positive isolates
collected in 1995 from 70 centers in 9 countries of Western Europe were examined,
using a standardized, quantitative susceptibility testing method. Of the 7078
isolates, 6824 (96.4%) were tested by the national coordinating centers.
Teicoplanin (mode MIC 0.5 microgram/mL) was generally twice as active as
vancomycin (mode MIC 1 microgram/mL) against Staphylococcus aureus (n = 2852).
All isolates were susceptible to vancomycin (MIC < or = 4 micrograms/mL) and all
but four to teicoplanin (MIC < or = 8 micrograms/mL); these four isolates were of
intermediate susceptibility (MIC 16 micrograms/mL). With coagulase-negative
staphylococci (n = 1444), the distribution of MIC of teicoplanin was wider than
for vancomycin. Two and two-tenths percent of coagulase-negative staphylococci
excluding Staphylococcus haemolyticus required 16 micrograms/mL teicoplanin for
inhibition (intermediate) and 0.4% > or = 32 micrograms/mL (resistant). Among
isolates of S. haemolyticus, 4.4% were of intermediate susceptibility (MIC 16
micrograms/mL) and 3.3% were resistant (MIC > or = 32 micrograms/mL) to
teicoplanin. However, this species represented only 6.3% of the isolates of
coagulase-negative Staphylococcus spp. Generally, teicoplanin (mode MIC < or =
0.12 microgram/mL) was four to eight times more active than vancomycin (mode MIC
< or = 0.5 microgram/mL) against the 770 streptococcal isolates. Glycopeptide
susceptible Enterococcus spp. (n = 1695) were generally four times more
susceptible to teicoplanin (mode MIC 0.25 microgram/mL) than to vancomycin (mode
MIC 1 microgram/mL). Combined vancomycin and teicoplanin (VanA phenotype)
resistance was observed more frequently (9.3%) in isolates of Enterococcus
faecium than in Enterococcus faecalis (0.8%). Four isolates of unspeciated
enterococci (1.4%) also expressed this resistance phenotype. Four isolates of E.
faecium and four of E. faecalis expressed the VanB-type (low-level, vancomycin
only) resistance. Spain was the only country not to submit resistant E. faecium
strains while resistant E. faecalis isolates came only from Spain and Italy.
PMID- 9764398
TI - In vitro evaluation of a novel orally administered cephalosporin (Cefditoren)
tested against 1249 recent clinical isolates of Haemophilus influenzae, Moraxella
catarrhalis, and Streptococcus pneumoniae.
AB - Cefditoren (formerly ME-1206), a new orally administered cephalosporin, was
evaluated in vitro against 1249 recently isolated strains of Streptococcus
pneumoniae (500 strains), Moraxella catarrhalis (250 strains), and Haemophilus
influenzae (499 strains). Reference National Committee for Clinical Laboratory
Standards methods were used and the strains were representative for the current
rates of beta-lactamase production or penicillin resistance. Cefditoren had
MIC50/MIC90 results for Moraxella catarrhalis and Haemophilus influenzae of
0.12/0.5 and < or = 0.008/0.015 microgram/mL, respectively. The pneumococci were
consistently twofold to eightfold more susceptible to cefditoren than other oral
cephalosporins or penicillins. The MIC90 for penicillin-resistant S. pneumoniae
was only 2 micrograms cefditoren/mL, and the highest recorded MIC was 4
micrograms/mL. Cefditoren appears to be a very promising beta-lactam possessing
the greatest potency and potential spectrum versus contemporary (1997)
respiratory tract pathogens.
PMID- 9764399
TI - Properties and functions of feline herpesvirus type 1 glycoproteins.
AB - Feline herpesvirus type 1 (FHV-1) is a causative agent of feline viral
rhinotracheitis and belongs to the subfamily Alphaherpesvirinae of the family
Herpesviridae. Since first isolated in 1958 by Crandell and Maurer, FHV-1 is
distributed worldwide and is the most clinically significant agent for
respiratory infections in cats. In this review, we describe the recent findings
with properties and functions of FHV-1 glycoproteins, especially hemagglutinins.
PMID- 9764400
TI - Cytotoxicity induced by recombinant human tumor necrosis factor-alpha dependent
on the types of its receptors on canine cells.
AB - Based on the recent findings that show how recombinant human tumor necrosis
factor (rh-TNF)-alpha has potent antitumor activity on human cancer patients when
it locally administrated, we have tested the cytotoxicity of rh-TNF-alpha on 3
canine cultured cells: (1) canine kidney carcinoma (CKCa-1), (2) mastocytoma and
(3) Mardin Darby canine kidney cells (MDCK). The cell surface expression of TNF
alpha receptors on these canine cells was also determined with anti-human TNF RI
and RII polyclonal antibodies. Our data shows that on CKCa-1 which has TNF RI
receptors rh-TNF-alpha induced cytotoxicity. By contrast, it exhibited no
toxicity on canine mastocytoma which has mainly RII receptors. The data also
suggest actinomycin D (ACT-D), an anticancer antibiotic, enhanced the
cytotoxicity of rh-TNF-alpha. Combined with ACT-D, rh-TNF-alpha showed the
cytotoxicity on MDCK which possessed both TNF RI and RII receptors. The results
indicate that the cytotoxicity of rh-TNF-alpha depends on the presence of TNF RI
receptors on canine tumor cells.
PMID- 9764401
TI - Morphological analysis of olfactory receptor cells using whole-mount preparations
of the rat nasal mucosa.
AB - The distribution and entire shape of olfactory receptor cells were investigated
by means of whole-mount preparations of the nasal mucosa. Whole mucosa isolated
from the nasal septum of rats was processed, as "a free-floating section", and
examined by the avidin-biotin complex (ABC) method using antisera against protein
gene product 9.5 (PGP 9.5) and calbindin. Essentially all receptor cells were
immunolabeled with the PGP 9.5 antiserum, but only half of PGP 9.5-immunoreactive
cells were calbindin-immunoreactive. In the immunostaining of whole-mount
preparations, pretreatment of tissues by freeze-thawing and dipping in ethanol
and xylene greatly improved the permeability of antibodies. Overview of the nasal
septum showed that the dorsal and ventral portions of the rostral olfactory area
extended deeply into the respiratory area, making a "semi-lunar" shape. The
boundary between the two areas was clearly demarcated, although several receptor
cells were scattered in the respiratory area near the boundary. Observation at
higher magnification clearly demonstrated that several axons derived from
perikarya gathered to form nerve bundles showing a dendritic pattern. Proximal
axons close to perikarya displayed beaded structures with intense
immunoreactivity. They were electron-microscopically identified as swollen
portions of axons which might be formed in association with the axonal flow. The
present study showed that whole-mount preparation of the nasal mucosa for
immunohistochemistry is a useful tool to analyze the morphology of olfactory
receptor cells and axons.
PMID- 9764402
TI - Influence of cell surface glycoprotein gC produced by pseudorabies virus on
cytopathic effect.
AB - The wild-type pseudorabies virus (WT-PRV) produced a round-type cytopathic effect
(CPE) in PK-15 cell line of porcine kidney origin, while PRVgCs lacking in gC
transmembrane-anchor region and PRVgC-defecting in gC gene produced a syncytium
type CPE. The mouse embryo cell line (BALB/3T3 clone A31) were transfected with
recombinant plasmid of pcDNA3 which incorporated with gC gene. The transfected
A31/gC cells were stably expressing gC. Only a round-type CPE was observed in
these cells infected with WT-PRV, while a syncytium-type CPE was observed in the
cells infected with each of the PRVgCs and PRVgC-. Any viruses described above
induced a syncytium-type CPE in A31/pcDNA cells transfected with a plasmid
without gC gene. By WT-PRV infection, PK-15 cells generated about 2- or 8-fold
more gC than the A31/gC and A31/pcDNA cells when gC was measured by
hemagglutination test. Flowcytometric analysis revealed that amount of gC on the
cell surface of A31/gC and PK-15 cells increased after infection with WT-PRV.
Round-type CPE was observed with the increase of gC. These results suggest that
the type of CPE formation induced by PRV is dominated by the amount of gC on the
infected cell surface.
PMID- 9764403
TI - Clinical effects of the recombinant feline interferon-omega on experimental
parvovirus infection in beagle dogs.
AB - The clinical effects of recombinant feline interferon-omega (rFeIFN-omega),
produced in silkworm by recombinant baculovirus, were examined in 3-4 month-old
beagle dogs given an experimental canine parvovirus type-2 (CPV-2) infection.
Clinical symptoms, such as pyrexia, vomiting, anorexia and diarrhea, were
observed on day 4 after oral inoculation of 10(7) TCID50 of CPV-2 (cc 238 strain)
in almost all the inoculated dogs. From day 4, rFeIFN-omega (1 mega units/kg/day)
or physiological saline was administered intravenously to infected dogs for 3
consecutive days. Seven out of 17 dogs treated with physiological saline showed
hemorrhagic diarrhea and continuously expressed severe clinical enteritis; one
dog died with a large amount of hemorrhagic rice-water stool on day 6 after viral
exposure. In contrast, 4 out of 12 dogs treated with rFeIFN-omega showed severe
clinical enteritis associated with intermittent diarrhea. Scoring of fecal
condition revealed that treatment with rFeIFN-omega significantly shifted the
enteritis from a severe to mild form. Furthermore, rFeIFN-omega administered in
the morning decreased the number of dogs expressing clinical enteritis in the
evening suggesting a rapid effect. Vomiting and anorexia were also improved by
treatment with rFeIFN-omega. These results suggest that rFeIFN-omega can reduce
severe enteritis caused by CPV-2 infection in dogs.
PMID- 9764404
TI - Genetic characterization of parainfluenza virus 3 derived from guinea pigs.
AB - To understand the relationship between novel parainfluenza virus 3 (PIV-3), which
has recently been isolated from the lungs of guinea pigs, and other PIV-3
strains, we determined the complete nucleotide sequence of the novel PIV-3 (GPv)
genome. A comparison of the nucleotide sequence among PIV-3s, including bovine
PIV-3, revealed that GPv is closely related to human PIV-3. The results of the
phylogenetic analysis clearly showed that GPv is a lineage of human PIV-3,
suggesting that GPv has probably been introduced into guinea pig colonies via
infected humans.
PMID- 9764405
TI - Analysis of tumor suppressor gene p53 in chicken lymphoblastoid tumor cell lines
and field tumors.
AB - To determine whether there is any abnormalities of the p53 gene in chicken
lymphoblastoid tumor cell lines derived from Marek's disease (MD), lymphoid
leukosis, reticuloendotheliosis, and field tumors, some portions of p53 cDNA
corresponding to core and C-terminal domains (nucleotide positions 277-1104 in
the p53 open reading frame (ORF)) were sequenced. Several mutations were
identified in both cell lines and field tumors. However, none of these mutations
is localized at the "hot spot", which has been reported as the site for
transformation-activating mutations. Moreover, partial cDNA clones with a 122-bp
deletion in the p53 ORF were identified in two cell lines, MSB1 and MTB1 derived
from MD tumors. Southern blot analysis showed that no deletion occurred in the
genome of p53 in MSB1, indicating that deletion occurred at the transcriptional
level. This deletion could cause a frame shift of the encoding p53 protein,
possibly resulting in the generation of a functionally different p53 protein.
However, we confirmed that p53 mRNA without deletion is also present in each of
these cell lines. These mutations of the p53 gene and deletion in the p53
transcript may be ones of molecular changes specific to the transformation
induced by MD virus.
PMID- 9764406
TI - Establishment and characterization of a new cell line derived from feline mammary
tumor.
AB - A new cell line designated FRM was established from pleural effusion of a 13-year
old female cat with mammary adenocarcinoma. The cell line exhibited irregular
round and polygonal shaped epithelial cells and demonstrated cell growth in a
monolayer fashion with a doubling time of 22.4 hr. It possessed a modal
chromosome number of 79. The immortality of this cell line was demonstrated using
the TRAP assay which revealed a high telomeric activity of these cells. Scatchard
analysis revealed quite low levels of estrogen receptors in both tumor mass
produced in nude mice and FRM cells. Subcutaneous transplantation of the cells
produced localized palpable masses in athymic nude mice within two weeks. This
cell line may provide a good model for in vivo and in vitro studies on feline
mammary tumors.
PMID- 9764407
TI - Expression of inhibin alpha-subunit in horse testis.
AB - Inhibin is believed to play roles in the pituitary secretion of FSH and in the
paracrine regulation of testicular function. Although it has been generally
accepted that inhibin is produced in Sertoli cells, there was a recent evidence
for the localization of inhibin in Leydig cells of primates, rat and sheep.
However, there is no report on the expression of inhibin in the adult horse
testis. Therefore, using immunohistochemistry, western blotting and in situ
hybridization techniques, the present study examined inhibin alpha-subunit (Ih
alpha) expression in the adult horse testis. For the detection of Ih-alpha
protein, we used anti-porcine Ih-alpha antibody in immunohistochemistry and
western blotting. Furthermore, digoxigenin-labeled complementary RNA probes were
prepared to detect intracellular messenger RNA (mRNA) of Ih-alpha.
Immunostainings for Ih-alpha were found not only in Leydig cells but also in
Sertoli cells. The intensity in Leydig cells was stronger than in Sertoli cells.
Immunoreactivities for Ih-alpha were found at approximately 46 kDa, 56 kDa and 90
kDa in the homogenates from testicular interstitial tissues. The bands at 56 kDa
and 90 kDa agree with previous report, but not at 46 kDa. Signals for mRNA of Ih
alpha by in situ hybridization were detected in Leydig cells and in the basal
region of seminiferous epithelium including Sertoli cells. These results suggest
that Ih-alpha is expressed in Leydig cells and Sertoli cells of horse testis, and
the expression level should be higher in Leydig cells than Sertoli cells.
PMID- 9764408
TI - Changes in iron and ferritin in anemic calves infected with Theileria sergenti.
AB - Changes in iron and ferritin in calves infected with Theileria sergenti were
investigated to elucidate iron metabolism in animals with extravascular hemolytic
anemia. During severe anemia, serum iron was remarkably elevated while the total
iron-binding capacity remained relatively unchanged or decreased slightly in the
infected calves, resulting in elevated transferrin saturation. The serum ferritin
concentration gradually increased with the progress of anemia. The erythrocyte
ferritin content drastically increased when mean corpuscular volume was elevated.
The concentration of non-heme iron and ferritin in the liver, spleen, and bone
marrow of the infected calves was markedly higher than that in the respective
tissues of the control animals. In particular, the liver of the anemic calves was
found to contain 23 and 35 times as much non-heme iron and ferritin,
respectively, as that of the non-anemic healthy cattle. The liver type (L) to
heart type (H) subunit ratio of liver ferritin was significantly higher in the
protozoa-infected than in the non-infected cattle. On the other hand, the L/H
ratio of marrow ferritin was significantly reduced by the anemia. These results
indicate that the anemic calves infected with T. sergenti apparently present
symptoms of iron overload.
PMID- 9764409
TI - Histopathological study of experimental acute poisoning of cattle by autumn
crocus (Colchicum autumnale L.).
AB - Crude or dehydrated bulbs of autumn crocus (Colchicum autumnale L.) were fed to
eleven calves. All the calves developed severe diarrhea and died or euthanized
within 63 hr. At necropsy, the gastro-intestinal mucosa was edematous and
hemorrhagic. Histologically, necrosis and degeneration with karyopyknosis and
karyorrhexis were shown in the basal cell layer of the tongue, esophagus,
forestomach, renal pelvis, urinary bladder, neck cell layer of the abomasal
gastric glands, and intestinal cryps. These findings were also seen in Kupffer
cells, renal tubular epithelial cells, and lymphocytes in the lymphoid and
hemopoietic systems. The lesion of the present acute crocus poisoning of cattle
closely resembled those reported in humans with colchicine intoxication. Refined
acetone extract of organs of poisoned cattle proved to contain colchicine and
demecolcine by high performance liquid chromatography.
PMID- 9764410
TI - Characteristics of lectin staining patterns assessed by a modified sensitive
thermo-method in rat livers with heterologous serum-induced fibrosis.
AB - Lectins are sensitive probes which bind carbohydrate structures specifically. In
this study, we modified the lectin staining procedure for sensitive detection of
carbohydrate structures in formalin-fixed, paraffin-embedded sections of normal
and heterologous serum-induced fibrotic livers. The liver sections were heated in
hot distilled water at 100 degrees C for 10 min (thermo-treatment: TT), and then
stained with 24 different lectins. In comparison with the results from sections
without TT (nonTT), enhanced and/or alternated staining patterns of 19 lectins
were demonstrated in sections with TT, and enhanced staining of Vicia villosa
agglutinin seen in Kupffer cells was noted. Interestingly, no positive staining
was seen with Dolichos biflorus agglutinin, peanut agglutinin or soybean
agglutinin (SBA), which recognize O-linked carbohydrate chains, in Kupffer cells
of non-TT sections, but strong positive staining was demonstrated in those of TT
sections. SBA-positive staining in the cytoplasm of some scattered hepatocytes
located in the periportal and perifibrous zones and central zone of pseudolobules
was demonstrated only in the fibrotic liver sections with TT. Such findings
indicate the heterogeneity of hepatocytes in the liver with fibrosis. Formalin
fixation causes masking of lectin binding sites, especially O-linked carbohydrate
chains, and TT may recover such masking reactions. TT improved the staining
reactions for many lectins in formalin-fixed, paraffin-embedded liver sections,
and new staining patterns appear after TT. Modified TT staining procedures may be
useful for the diagnosis and prognosis of liver fibrosis.
PMID- 9764411
TI - Superovulatory responses in Japanese black beef cows following largest follicle
aspiration or human chorionic gonadotrophin (hCG) treatment.
AB - The effect of largest follicle aspiration or hCG administration before induction
of superovulation on the ovarian response of Japanese Black beef cows was
investigated using a crossover design in which induction of superovulation was
attempted in every cow. The superovulatory response of cows whose largest
follicle had been aspirated from the ovaries by ultrasound-guided follicular
aspiration 1 day before induction of superovulation, did not differ from the
response in non-treated control cows. In contrast, in cows given 5,000 IU of hCG
3 days before induction of superovulation, the proportions of fertilized ova and
transferable embryos significantly decreased compared with the other groups.
PMID- 9764412
TI - Electroejaculation and semen characteristics of the captive Hokkaido brown bear
(Ursus arctos yesoensis).
AB - An electroejaculation technique was applied to the Hokkaido brown bear (Ursus
arctos yesoensis) for semen collection and characterization of their seminal
traits. Ten captive sexually mature bears were anesthetized and subjected to 21
electroejaculation trials during their mating season in 1995 and 1996. Spermic
electroejaculates were recovered from 6 of the 10 bears (14 of 21 trials). The
semen was characterized by serous fluid of semitransparent white color and a
neutral pH. The mean values of ejaculate volume, sperm concentration, percentage
of sperm motility, percentage of live spermatozoa, and percentage of pleiomorphic
forms were 2.7 ml, 471.6 x 10(6) cells/ml, 80.2%, 89.7% and 21.8%, respectively.
Although there was considerable variation among the seminal traits of the
individual bears, the electroejaculation technique was effective in obtaining
ejaculates from captive bears.
PMID- 9764413
TI - Higher sensitivity in LEC rat cells to a topoisomerase II inhibitor, ellipticine.
AB - A concentration of ellipticine, an inhibitor of topoisomerase II, required to
reduce cell survival to 37% (D37) is used as an index to compare the cellular
sensitivity. D37 values of LEC and WKAH rat cells were 1.2 and 2.2 microM,
respectively. Thus, LEC rat cells were approximately 1.8-fold more sensitive than
WKAH rat cells to ellipticine. There was no significant difference between the
topoisomerase II activities in nuclear extracts of LEC and WKAH rat cells. These
results suggested that the high sensitivity of LEC rat cells to ellipticine is
not associated with the level of topoisomerase II activity.
PMID- 9764414
TI - New quantitative methods for detection of feline parvovirus (FPV) and virus
neutralizing antibody against FPV using a feline T lymphoid cell line.
AB - Previously, we reported that a feline T lymphoid cell line, FL74 cells, was very
sensitive to feline parvovirus (FPV) infection. In the present study, we
developed new quantitative methods for detection of FPV and virus neutralizing
antibody against FPV using FL74 cells. The methods presented here were very
simple and applicable to both canine parvovirus and feline panleukopenia virus.
PMID- 9764415
TI - Canine mesenchymal chondrosarcoma of the ribs.
AB - The tumor of the thoracic cavity, which arose from the ribs, was diagnosed as
mesenchymal chondrosarcoma. No distant metastasis was observed. Histologically,
the tumor was characterized by the nests of well-defined cartilaginous tissue
within a proliferation of primitive mesenchymal cells. Additionally, the deformed
blood vessels compressed by the proliferating mesenchymal cells exhibited clear
stag-horn appearance. Immunohistochemically, most neoplastic cells that formed
multifocal cartilaginous islands were positive for S-100 protein, while the
surrounding mesenchymal cells were negative. This is the first report of canine
mesenchymal chondrosarcoma of the ribs.
PMID- 9764416
TI - Gastric mucormycosis in a sika deer (Cervus nippon) associated with proliferation
of Clostridium perfringens.
AB - Seven sika deer (Cervus nippon) died in a park where 30 deer were kept. One adult
female deer died suddenly was necropsied. Severe hemorrhages were noted beneath
the serous membranes of the forestomach and abomasum. Hyphal proliferation with
neutrophil infiltration was observed in the mucous membranes of the stomaches,
and the hyphae showed characteristics of order Mucorales. Catarrhal enteritis
with hemorrhages was also observed. A large number of Clostridium perfringens was
isolated from the contents of the abomasum and small intestine. The case was
diagnosed as gastric mucormycosis associated with proliferation of Clostridium
perfringens. The incidence occurred during breeding season and incorrect
management was considered to be a predisposing factor for the infection.
PMID- 9764417
TI - Presence of 22- and 17-kDa proteins reacting with sera in mice experimentally
infected with Brachyspira (Serpulina) hyodysenteriae.
AB - The antibodies to B. (S.)hyodysenteriae in experimentally infected mice were
detected by microscopic agglutination test (MAT) and enzyme-linked immunosorbent
assay (ELISA). The reactions in MAT were serotype specific while those in ELISA
were common to both strains. A further investigation with immunoblotting
technique demonstrated that 22- and 17-kDa proteins reacted strongly with the
sera. The proteins in ATCC 27164 strain strongly reacted with the serum from ATCC
31212 strain-infected mouse and vice versa. These proteins were sensitive to
proteinase K.
PMID- 9764418
TI - Enhancement of neonatal rat ductal responsiveness to prostaglandin E2 after
maternal treatment with enalapril or captopril.
AB - This work was conducted to determine whether the angiotensin-converting enzyme
inhibitors (ACEIs) (enalapril and captopril) administered to mother rats
prenatally can potentiate a re-opening of the neonatal ductus arteriosus (DA)
induced by prostaglandin E2 (PGE2) after postnatal closure. A subcutaneous
injection of PGE2 (4 micrograms) was administered to newborn rats 3 hr after a
Cesarean delivery from females which had been orally given 0.1, 1 or 10 mg/kg/day
of enalapril or 15 or 150 mg/kg/day of captopril from day 14 to day 20 of
gestation. The ratio of the DA to the pulmonary artery (PA) was determined at
intervals after the injection. The DA/PA ratio was significantly higher in the
newborn rats of mothers who were transplacentally administered these agents
compared to the controls, except at the low dose (0.1 mg/kg) group of enalapril.
We found that the level in the neonatal lungs of 15-hydroxy prostaglandin
dehydrogenase, a key enzyme that catalyzes PGE2 to convert it to its inactive
metabolite 15-keto-PGE2, was not affected after maternal treatment with enalapril
or captopril. These results indicate that the increased ductal responsiveness to
PGE2 in newborn rats was a common response after maternal ACEI treatment, but the
catabolism of PGE2 in the lungs did not contribute to this response.
PMID- 9764419
TI - Paraquat: a useful tool for the in vivo study of mechanisms of neuronal cell
death.
AB - The present article reviews the results of experimental studies on paraquat
neurotoxicity, started by our group several years ago--when clinical and
experimental reports had increased the interest for the possibility that
environmental chemicals, including paraquat, may be related to the development of
Parkinson's disease-, and which are still continuing since paraquat appears to be
a promising tool to study the mechanisms of neuronal cell death in vivo. Our
observations have demonstrated that paraquat causes evident neurotoxic effects
after intracerebroventricular or intracerebral injection in experimental animals;
however, it seems that the herbicide does not exibit a selective neurotoxicity
towards the dopaminergic nigro-striatal system since potent behavioural and
electrocortical changes are induced by paraquat after injection in brain areas
other than the substantia nigra and caudate nucleus. By studying the mechanisms
through which paraquat induces neurotoxic effects in vivo, it was shown that
either free radical production and activation of cholinergic and glutamatergic
transmission may be regarded as related events which play a crucial role in
paraquat-induced neurotoxicity. In addition, it was observed that in rats
paraquat penetrates the blood-brain barrier following systemic administration to
give rise to a differential brain regional distribution; the latter observation
rises some concern over the hazard of paraquat as a potential environmental
neurotoxin. Indeed, paraquat, administered systemically in rats produces
behavioural excitation and brain damage. The brain damage appears to be selective
for the pyriform cortex and this does not seem to be strictly related to the high
concentrations reached by the herbicide in this area but to the higher
vulnerability of this cortical area to the enhanced cholinergic transmission. The
recent observation that paraquat, injected into the rat hippocampus, induces the
expression of apoptotic neuronal cell death, appears of valuable interest also
with a view to paraquat as an useful experimental model in the development of
neuroprotective drugs able to block the molecular events which, once activated,
are responsible for the induction of neuronal cell death.
PMID- 9764420
TI - Gadolinium chloride inhibition of pulmonary nitric oxide production and effects
on pulmonary circulation in the rabbit.
AB - Nitric oxide is an important regulator of pulmonary vascular resistance.
Pulmonary nitric oxide formation is detectable in exhaled air and the synthesis
is partly stretch-dependent. Gadolinium chloride (GdCl3) reduces pulmonary nitric
oxide formation, possibly by interference with stretch-activated cellular calcium
influx, but the effect on pulmonary circulation is not known. We therefore
measured exhaled nitric oxide and pulmonary vascular resistance in anaesthetised
rabbits, and compared the effects of GdCl3 with those of an nitric oxide-synthase
inhibitor (L-N omega-nitro-arginine methyl ester, L-NAME). Both GdCl3 and L-NAME
reduced nitric oxide in exhaled air and increased pulmonary vascular resistance.
However, the increase in pulmonary vascular resistance was more pronounced with
GdCl3 than with L-NAME. A 50% reduction of exhaled nitric oxide caused by either
GdCl3 or L-NAME was accompanied by a 90% or 17% increase in pulmonary vascular
resistance respectively. Inhaled nitric oxide (40 ppm) reduced pulmonary vascular
resistance after L-NAME, but not after GdCl3 infusion. Infusion of
glyceryltrinitrate reduced pulmonary vascular resistance after GdCl3 infusion.
GdCl3 caused hypoxaemia, probably due to vasoconstriction since lung weight was
unaltered. Thus GdCl3 can induce a marked increase in pulmonary vascular
resistance, which partly may be caused by inhibition of pulmonary nitric oxide
formation. Intact stretch-activated calcium channels may be important for
maintenance of normal pulmonary vascular function.
PMID- 9764421
TI - Effects of ATP-sensitive potassium channel opener on potassium transport and
alveolar fluid clearance in the resected human lung.
AB - Since the effect of an ATP-sensitive potassium channel (KATP channel) opener on
the function of alveolar epithelial cells is unknown, the effect of YM934, a
newly synthesized KATP channel opener, on potassium influx into the alveolar
spaces and alveolar fluid clearance was determined in the resected human lung. An
isosmolar albumin solution with a low potassium concentration was instilled into
the distal airspaces of resected human lungs. Alveolar fluid clearance was
measured by the progressive increase in alveolar protein concentration. Net
potassium transport was measured by the change in potassium concentration and
alveolar fluid volume. YM934 (10(-4) M) increased net influx of potassium by 140%
into the alveolar spaces and also increased alveolar fluid clearance by 60% in
the experiments with a potassium concentration of 0.3 mEq/1. Glibenclamide (10(
4) M), a KATP channel blocker, inhibited the YM934-increased influx of potassium
transport and the increase in alveolar fluid clearance. Also amiloride (10(-5)
M), an inhibitors of apical sodium uptake, blocked the YM934 stimulated increase
in net alveolar fluid clearance. These results indicate that a KATP channel
opener can effect potassium transport and net vectorial fluid movement across the
human alveolar epithelium.
PMID- 9764422
TI - Effect of concomitant beta-adrenoceptor stimulation on alpha 1-adrenoceptor
mediated increase of inositol-1,4,5-trisphosphate mass in adult rat
cardiomyocytes.
AB - The aim of the present study was to investigate the accumulation of inositol
1,4,5-trisphosphate (IP3) in isolated adult rat ventricular cardiomyocytes after
alpha 1- and beta-adrenoceptor stimulation, separate and in combination, in order
to elucidate a possible influence of concomitant beta-adrenoceptor stimulation on
the alpha 1-adrenoceptor stimulated response. IP3 was measured by a radioligand
binding assay based on an (1,4,5)IP3-specific binding protein from bovine adrenal
cortex. The basal IP3 content was 4.06 +/- 0.31 pmol/mg protein (N = 56). alpha 1
Adrenoceptor stimulation resulted in a rapid increase in the IP3 level, which
reached a plateau, 50-80% above basal level, at 10-30 sec. The plateau lasted at
least up to 120 sec., while at 300 sec. there was no significant difference
between control values and values after alpha 1-adrenoceptor stimulation. Li+ did
not affect either the basal IP3 level, or the magnitude or time course of alpha 1
adrenoceptor-stimulated IP3 accumulation. Combined adrenoceptor stimulation gave
a similar response as separate alpha 1-adrenoceptor stimulation, whereas there
was no significant change in the IP3 level after beta-adrenoceptor stimulation.
No inhibitory influence of simultaneous beta-adrenoceptor stimulation on the
alpha 1-adrenoceptor-stimulated increase of IP3 mass was revealed.
PMID- 9764423
TI - Growth modulating effects of chlorinated oleic acid in cell cultures.
AB - Chlorinated fatty acids represent a major fraction of extractable, organically
bound chlorine in fish. After dietary intake such fatty acids may be transferred
from the mother to the foetus through the placenta, and via breast milk to the
child. In the present work we have studied the effect of chlorinated oleic acid
on the growth of three widely differing types of cells in culture. Chlorinated
oleic acid inhibited growth of Human Microvascular Endothelial Cells (HMVEC),
Immortilized Human Kidney Epithelial (IHKE) cells, and human Hepatoma cells
(HepG2). The order of potency was: HMVEC > IHKE > HepG2. Vitamin E counteracted
the inhibitory effect of chlorinated oleic acid on HepG2 cells, but did not
significantly affect the fatty acid effect on HMVEC or IHKE. Defatted serum
albumin stimulated the growth of HMVEC and IHKE. With HMVEC there was no major
interaction between the effect of albumin and chlorinated oleic acid on cell
growth. In contrast, with IHKE albumin at low concentration abolished the growth
inhibiting effect of chlorinated oleic acid and appreciably counteracted growth
inhibition by the fatty acid of HepG2. We conclude that the growth modulation by
chlorinated oleic acid and its interaction with vitamin E and albumin are cell
specific.
PMID- 9764424
TI - Methamphetamine-induced modification of dopamine metabolism in cultured striatal
astrocytes.
AB - The role of striatal astrocytes in the metabolic processing (by deamination) of
methamphetamine-released dopamine is not known. To investigate the relationship
between methamphetamine and dopamine metabolism, we measured 6-hydroxydopamine,
dopamine and, 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations following
methamphetamine treatment of cultured striatal astrocytes prepared from 1-2 day
old rats. Addition of low concentrations of dopamine (5 x 10(-5) to 5 x 10(-4) M)
to cultured astrocytes increased DOPAC levels in a dose-dependent fashion while
higher concentrations (5 x 10(-3) to 10(-2) M) inhibited its metabolism and
induced formation of 6-hydroxydopamine. Under the same experimental conditions,
10(-4) M dopamine in combination with methamphetamine (10(-5) to 10(-3) M)
inhibited DOPAC formation and increased dopamine levels in a dose-dependent
fashion, but the formation of intracellular 6-hydroxydopamine was not evident.
Deprenyl (10(-5) or 10(-4) M), an inhibitor of monoamine oxidase B, and pargyline
(10(-5) or 10(-4) M), a non-selective monoamine oxidase inhibitor, completely
inhibited DOPAC formation and increased dopamine levels, while clorgyline (10(-5)
or 10(-4) M), an inhibitor of monoamine oxidase-A, only partially inhibited DOPAC
formation (42 or 45% of control, respectively). These results support the
hypothesis that methamphetamine inhibits monoamine oxidase and causes increases
in dopamine levels in cultured striatal astrocytes.
PMID- 9764425
TI - Characterization of t-butyl hydroperoxide toxicity in cultured rat cortical
neurones and astrocytes.
AB - The present study investigates the toxicity of t-butyl hydroperoxide (t-BuOOH) in
cultured rat cortical neurones and astrocytes. Both neurones and astrocytes were
destroyed by exposure to t-BuOOH in a time- and concentration-dependent manner.
Astrocytes were more resistant to destruction by hydrogen peroxide (H2O2) than
neurones, but there was no difference in susceptibility to t-BuOOH between
neurones and astrocytes. The toxic effect of t-BuOOH was significantly blocked by
antioxidants, propyl gallate and trolox, but not by superoxide dismutase nor by
H2O2-scavengers, catalase and 4-nitrophenylglyoxylic acid. These results suggest
that t-BuOOH toxicity is caused by oxidative stress unrelated to superoxide and
H2O2. In addition, the toxic effect of t-BuOOH was attenuated by the presence of
iron chelators, deferoxamine and N,N,N',N'-tetrakis(2
pyridylmethyl)ethylenediamine, indicating the requirement of endogenous iron for
t-BuOOH toxicity.
PMID- 9764426
TI - Advantages and pitfalls of macrostatistics for health planning at the local as
well as top national level.
PMID- 9764427
TI - Late postoperative respiratory function in adults after surgical correction of
atrial septal defects. Analysis of respiratory dysfunction patterns.
AB - Respiratory function after repair of atrial septal defect (ASD) was analysed in
44 adults (> 40 years), 21 of whom had preoperative respiratory dysfunction, 14
of restrictive type, defined as % vital capacity (% VC) less than 80% of
predicted value, 3 with an obstructive pattern, defined as % forced expiratory
volume/1 s (% FEV1) less than 70% of predicted value, and 4 patients with a mixed
pattern. Increased % VC was found postoperatively in all 14 patients with
restrictive respiratory dysfunction, with normal values in 8 out of the 14.
Although the three patients with obstructive, and the four with mixed-pattern
respiratory dysfunction improved preoperatively in % VC or % FEV1, or both, none
had normalized values. We conclude that preoperative restrictive respiratory
dysfunction in ASD patients frequently normalizes postoperatively, but not
dysfunction of obstructive or mixed restrictive-obstructive type.
PMID- 9764428
TI - Effects of a novel pneumatic vest on postoperative pain and lung function after
coronary artery bypass grafting.
AB - A prospective study to evaluate the efficacy of a novel inflatable vest in
supporting the sternotomy wound during the early period after coronary artery
bypass grafting was carried out in 35 patients. The outcome variables were
subjective pain score during cough, and peak expiratory flow (PEF) and vital
capacity (VC) on postoperative days 2 and 3. The values without pressure in the
vest were used as controls in the individual patients. Use of the vest
significantly reduced the cough-associated subjective sternotomy pain score on
days 2 and 3, when significant reduction of PEF and VC was also observed. The
alleviation of pain by the inflatable vest may improve the efficacy of coughing
and bronchial clearance in the immediate postoperative period.
PMID- 9764429
TI - Assessment of myocardial glutamate requirements early after coronary artery
bypass surgery.
AB - Glutamate is an important substrate for the intermediary metabolism of the heart,
particularly in association with ischemia. Early after coronary artery bypass
surgery (CABG) myocardial uptake of glutamate seems to be limited by substrate
availability (arterial levels). However, glutamate is not an innocuous substrate.
As arterial levels of glutamate are important both for myocardial uptake and
adverse effects, an attempt was made to determine a minimum dose of glutamate
sufficient to supply the needs of the heart after CABG. Ten patients received and
infusion of 220-240 ml of 0.1 M L-glutamic acid solution at varying rates during
two 30-min periods, starting 2 h after uncomplicated elective CABG. Intravenous
glutamate infusion caused a dose-dependent linear increase in arterial glutamate
and an increased myocardial uptake of glutamate. However, myocardial uptake of
glutamate correlated with arterial levels only at lower infusion rates. Although
maximal peak uptake in individual patients (6.6 +/- 1.1 mumol/min) occurred at an
average increase of arterial whole blood glutamate of 172 +/- 34 mumol/L, the
greatest impact on myocardial glutamate uptake was achieved by increasing
arterial whole blood glutamate by less than 100 mumol/L. This implies that an
infusion rate of 30-40 mg glutamate/kg BW/h could suffice to achieve a maximal or
near maximal myocardial glutamate uptake in most patients after CABG. The
adequacy of this dosage remains to be confirmed in high-risk patients.
PMID- 9764430
TI - Benign intrathoracic tumours. A population survey in northern Finland.
AB - Benign intrathoracic tumours are uncommon, but their occurrence in unselected
populations is poorly defined. We reviewed all cases of suspected intrathoracic
tumour in a population (440,000) in northern Finland during 1990 through 1992.
Diagnostic investigations included fiberoptic bronchoscopy and computed
tomography in all cases. Of the 653 intrathoracic tumours, 36 were benign. The
male/female ratio in these 36 cases was 1.25; the mean age was 54 years. Twenty
three of the lesions were symptomless, found at health check or examination for
other disease. Bronchoscopy did not confirm the diagnosis of any benign tumour.
Thoracotomy was considered necessary in most cases and histologic diagnosis was
therefore available in 24 (67%). Hamartoma was the most common benign lung
tumour. This prospective study in an unselected population confirms previous
findings in surgical series concerning benign intrathoracic tumours and their
histology.
PMID- 9764431
TI - Differences in heart rate variability in the acute phase of first and second
attacks of myocardial infarction.
AB - The purpose of the study was to examine the differences between first and second
myocardial infarctions with respect to improvement in measures of heart rate
variability (HRV). The study population comprised 48 non-diabetic patients with
acute myocardial infarction (AMI), and with angiographically documented coronary
artery occlusion and successful reperfusion. The subjects were grouped as 35
cases with a first AMI attack and 13 with their second AMI. Two weeks after the
onset of infarction, indices of HRV were higher in first infarction cases than in
second infarction cases. In the latter, there were no significant increases in
HRV indices from day of onset to 2 weeks later, nor were there any significant
changes in left ventricular ejection fraction (LVEF) from onset to 3 weeks later.
All patients studied had a patent infarct-related artery 3 weeks later. We found
sustained low values of HRV after a second AMI. Different risk stratification may
be needed between uncomplicated first AMI and second AMI cases.
PMID- 9764432
TI - Urinary albumin excretion in hospitalized patients with acute myocardial
infarction. Prevalence of microalbuminuria and correlation to left ventricle wall
thickness.
AB - Microalbuminuria, a subclinical rise in the urinary albumin excretion, is a risk
indicator of atherosclerotic cardiovascular disease. The aim of this study was to
measure the urinary albumin excretion in patients with acute myocardial
infarction, and to correlate this with known atherosclerotic risk factors. One
hundred-and-twenty-six patients and 56 healthy controls matched for age and sex
were studied. The albumin/creatinine concentration ratio in morning urine
specimens was calculated as an index of the albumin excretion. Microalbuminuria
was defined as a urinary albumin/creatinine concentration ratio above 1 mg/mmol.
Urinary albumin excretion (0.88 [95% confidence interval 0.69-1.11] versus 0.51
[0.40-0.63] mg/mmol; p = 0.001) and frequency of microalbuminuria (33 [95%
confidence interval 25-41] versus 16 [9-23]%; p = 0.03) were higher in patients
than controls. This difference was independent of blood pressure, body weight,
smoking, diabetes mellitus, renal disease, and thrombolytic treatment. There was
a positive correlation between urinary albumin excretion and thickness of the
left ventricle wall (R = 0.28; p = 0.001) which was independent of blood
pressure. Follow-up examination of the patients will reveal whether
microalbuminuria increases the risk for recurrence of acute myocardial
infarction.
PMID- 9764433
TI - Effect of amiloride on ischaemia and reperfusion injury in isolated, perfused rat
hearts.
AB - The effect of amiloride, a potent inhibitor of Na+/H+ exchange, on ischaemic
reperfused rat hearts was studied in order to investigate whether Na+/H+ exchange
or Na+/Ca2+ exchange is involved in ischaemia-reperfusion injury, When hearts
were pre-ischaemically loaded with 100 microM amiloride, recovery of left
ventricular developed pressure was significantly better than in control hearts,
whereas recovery of heart rate at 30-min reperfusion was unaffected. Amiloride
pretreatment also decreased creatine phosphokinase activity in the coronary
effluent and completely abolished occurrence of ventricular arrhythmias during
reperfusion. It also inhibited intracellular Na+ accumulation early in
reperfusion (within 5 min), whereas in the late stage (from 5 to 30 min), Ca2+
overload was inhibited. The findings suggest that Na+/H+ exchange participates
mainly in the early stage of reperfusion injury and the Na+/Ca2+ exchange system,
secondary to Na+/H+ exchange, in the late stage. The reduction in post-ischaemic
cardiac dysfunction induced by amiloride pretreatment may be attributable to
inhibition of the resultant Ca2+ accumulation during reperfusion.
PMID- 9764434
TI - Malignant transformation of an intrathoracic neurofibroma in von Recklinghausen's
disease.
AB - Malignant transformation of a mediastinal neurofibroma, presenting for many years
as a mass in the superior mediastinum and arising from the right vagus nerve, was
found in a patient with long-standing von Recklinghausen's disease. Surgical
management of intrathoracic neurogenic tumours, even if clinically benign, is
advocated.
PMID- 9764435
TI - Chondrosarcoma of the chest wall with Ollier's disease.
AB - A 15 x 15 cm mass in the right hemithorax of a 25-year-old woman was incidentally
detected at routine chest radiography. Radical excision of the bony chest wall,
including right CII-VI, revealed chondrosarcoma. Large, expansile parosteal
chondromas were radiographically visualized in the pelvis and bones of the lower
leg, representing Ollier's disease. Chondrosarcoma of the chest wall appears to
be rare in Ollier's disease.
PMID- 9764436
TI - Salmonella osteomyelitis of the rib.
AB - Salmonella rib osteomyelitis is extremely rare; we found only one previously
reported case. A 33-year-old man presenting with a discharging sternal sinus was
diagnosed by means of computed tomography and bone isotope scans and confirmed by
excision of the affected portion of the rib. The operation was curative.
PMID- 9764437
TI - Quantity and quality relationships in cardiovascular medicine.
AB - Hospital volume and often also operator volume have documented impacts on the
quality of care for aortic and aortocoronary bypass surgery, for percutaneous
angioplasty and for radiofrequency ablation for arrhythmias, whereas data are
less consistent for treatment of acute myocardial infarction. A review of this
research is given. In the Nordic countries hospitals are small, and often the
plateau of the learning curve cannot be reached. To discourage low-volume centers
from embarking upon too complicated interventional or surgical procedures, the
author suggests that a minimal number should be set for certain major procedures,
both for hospitals and for physicians.
PMID- 9764438
TI - Release and effects of calcitonin gene-related peptide in myocardial ischaemia.
AB - 1. Low pH and lactic acid perfusion evoke a reproducible, and concentration
dependent outflow of CGRP from the isolated heart. 2. PGI2 causes outflow of CGRP
from the isolated heart. Furthermore, low pH perfusion causes release of PGI2,
and cyclo-oxygenase inhibition attenuates not only this release of PGI2, but also
the outflow of CGRP that is evoked by low pH perfusion, indicating that a portion
of the C-fibre activation exerted by low pH is mediated by PGI2. 3. The outflow
of CGRP that is caused by low pH but not that evoked by capsaicin or PGI2 is
dependent on the endothelium, whereas the vasodilating effect of CGRP is
preserved after removal of the endothelium. 4. TTX attenuates release of CGRP
caused by low concentrations of capsaicin, indicating that an axon reflex
mechanism in the peripheral endings of C-fibre afferents can augment local
outflow of CGRP. 5. Outflow of CGRP evoked by low pH and capsaicin have common
features, such as sensitivity to RR and CPZ. N-type calcium channels are involved
in release of CGRP by both stimuli. 6. In the coronary vasculature, exogenous
CGRP augmented post-occlusive hyperaemia. 7. In the pig in vivo, CGRP causes
marked dose-dependent reduction of systemic vascular resistance. This effect of
CGRP was partly reduced by CGRP(8-37). 8. Capsaicin pretreatment resulted in
lower myocardial levels of CGRP, and ischaemic myocardium had lower content of
CGRP than non-ischaemic areas. Capsaicin-treated animals had larger myocardial
infarctions, possibly due to depletion of CGRP. When endogenous stores of CGRP
were intact, administration of additional CGRP to the ischaemic myocardium had no
cardioprotective effect. 9. In patients undergoing CABG without CPB, 10-20
minutes of local ischaemia (as evidenced by a net production of lactate) was
associated with increased levels of CGRP in coronary sinus blood. 10. Based on
the present findings it may therefore be suggested that local cardiac CGRP
release from capsaicin-sensitive C-fibre afferents during myocardial ischaemia
functions as an endogenous physiological protective response. The possibility
thus exists that effects of CGRP observed in animal studies may play a role in
human myocardial ischaemia.
PMID- 9764439
TI - Subtalar instability of the foot. A review and results after surgical treatment.
AB - Most subtalar ligamentous injuries occur in combination with ankle ligament
injuries, but the exact aetiology and the true incidence remain unknown. The aim
of this study was to review the problem, propose a definition and to analyze the
results of an anatomic reconstructive surgical technique in the treatment of
subtalar instability. Twenty-two patients suffering from chronic subtalar
instability of the foot were operated with anatomical reconstruction. The
cervical, the lateral talo-calcaneal and the calcaneo-fibular ligaments were
imbricated and reinforced with the lateral root of the inferior extensor
retinaculum. After a minimum of 2 years follow-up the functional results were
excellent or good in 18 of 22 (82%) patients and fair or poor in 4 of 22 (18%).
All of the patients with unsatisfactory results suffered from residual ankle
pain, two of whom also had residual instability. No reoperations have been
performed. Surgical complications were seen in three patients, all minor nerve
injuries of the lateral branch of the superficial peroneal nerve. These
complications had no bearing on the functional results, however. This procedure
was found to be feasible in patients with chronic subtalar instability.
PMID- 9764440
TI - Stabilometry and one-leg hop test have high test-retest reliability.
AB - The purpose of this study was to investigate the reliability of repeated
measurements and a possible learning or tiring process in single-limb
stabilometry and one-leg hop test. An additional purpose was to study the
correlation between different stabilometric variables. Seventy-five healthy
subjects were examined twice with a median interval of 7 d, and with three
consecutive measurements on each occasion. Single-limb stabilometry and one-leg
hop test were found to have high reliability (ICC r = 0.68-0.83 and 0.96,
respectively). The correlation between consecutive measurements was acceptable to
high in stabilometry (r = 0.42-0.90, P = 0.002-P < 0.001) and high in the one-leg
hop test (r = 0.91-0.97, P < 0.001). A learning process over time was observed.
The correlation between the stabilometric variables was high (r = 0.73-0.95, P <
0.001).
PMID- 9764441
TI - Aerobic endurance testing of children and adolescents--a comparison of two
treadmill-protocols.
AB - Fifty-eight children and adolescents of both sexes, aged 8-16, were tested on a
treadmill using two different protocols. The well-known Bruce-protocol has the
disadvantages of steep incline and large increments at each step. A new protocol
(Oslo-protocol) with less incline and smaller increments was compared to the
Bruce-protocol. The results from the two protocols showed no differences with
regard to peak oxygen uptake (VO2peak) or peak heart rate (HRpeak). However, the
respiratory exchange ratio (R) and blood lactate concentration [La-] showed
higher values when the Bruce-protocol was used. The study also indicated that the
often used criteria of HRpeak, R and achievement of a plateau in VO2 to estimate
VO2peak, were not reliable indicators in either protocol. When time to exhaustion
was used as an estimation of aerobic endurance level, the Oslo-protocol
discriminated better than the Bruce-protocol. As a conclusion, the results
indicate that none of the criteria may be used as a reliable indicator of having
achieved VO2peak. An experienced testleader may be essential to define when
VO2peak has been reached in children. On the basis of the results from the
current study, the Oslo-protocol seems suitable as a test-protocol when testing
children and adolescents for VO2peak.
PMID- 9764442
TI - Isokinetic eccentric exercise as a model to induce and reproduce
pathophysiological alterations related to delayed onset muscle soreness.
AB - Physiological alterations following unaccustomed eccentric exercise in an
isokinetic dynamometer of the right m. quadriceps until exhaustion were studied,
in order to create a model in which the physiological responses to physiotherapy
could be measured. In experiment I (exp. I), seven selected parameters were
measured bilaterally in 7 healthy subjects at day 0 as a control value. Then
after a standardized bout of eccentric exercise the same parameters were measured
daily for the following 7 d (test values). The measured parameters were: the
ratio of phosphocreatine to inorganic phosphate (PCr/Pi), the ratio of inorganic
phosphate to adenosintriphosphate (Pi/ATP), the ratio of phosphocreatine to
adenosintriphosphate (PCr/ATP) (all three ratios measured with 31P-nuclear
magnetic resonance spectroscopy), dynamic muscle strength, plasma creatine kinase
(CK), degree of pain and "muscle" blood flow rate (133Xenon washout technique).
This was repeated in experiment II (exp. II) 6-12 months later in order to study
reproducibility. In experiment III (exp. III), the normal fluctuations over 8 d
of the seven parameters were measured, without intervention with eccentric
exercise in 6 other subjects. All subjects experienced pain, reaching a maximum
48 h after eccentric exercise in both exp. I and II. A systematic effect over
time for CK (increasing 278% resp. 308%), muscle strength (decreasing more than
10%), PCr/Pi (decreasing 31% resp. 43%) and Pi/ATP (increasing 55% resp. 99%) was
found in both exp. I and II (P < 0.05), but not in exp. III. No significant
difference was observed between exp. I and II for CK, blood-flow rate, concentric
muscle strength, PCr/Pi, Pi/ATP and PCr/ATP. It is concluded that
pathophysiological alterations in m. quadriceps following eccentric exercise can
be induced and can be reproduced after an interval of 6 months. Thus, this model
can be used to study the effects of physiotherapy.
PMID- 9764443
TI - The effect of passive stretching on delayed onset muscle soreness, and other
detrimental effects following eccentric exercise.
AB - The aim of this study was to measure if passive stretching would influence
delayed onset muscle soreness (DOMS), dynamic muscle strength, plasma creatine
kinase concentration (CK) and the ratio of phosphocreatine to inorganic phosphate
(PCr/P(i)) following eccentric exercise. Seven healthy untrained women, 28-46
years old, performed eccentric exercise with the right m. quadriceps in an
isokinetic dynamometer (Biodex, angle velocity: 60 degrees.s-1) until exhaustion,
in two different experiments, with an interval of 13-23 months. In both
experiments the PCr/P(i) ratio, dynamic muscle strength, CK and muscle pain were
measured before the eccentric exercise (day 0) and the following 7 d. In the
second experiment daily passive stretching (3 times of 30 s duration, with a
pause of 30 s in between) of m. quadriceps was included in the protocol. The
stretching was performed before and immediately after the eccentric exercise at
day 0, and before measurements of the dependent variables daily for the following
7 d. The eccentric exercise alone led to significant decreases in PCr/P(i) ratio
(P < 0.001) and muscle strength (P < 0.001), and an increase in CK concentration
(P < 0.01). All subjects reported pain in the right m. quadriceps with a peak 48
h after exercise. There was no difference in the reported variables between
experiments one and two. It is concluded that passive stretching did not have any
significant influence on increased plasma-CK, muscle pain, muscle strength and
the PCr/P(i) ratio, indicating that passive stretching after eccentric exercise
cannot prevent secondary pathological alterations.
PMID- 9764444
TI - The energy cost of level walking before and after hydro-kinesi therapy in
patients with spastic paresis.
AB - In this study the energy cost of level walking was measured in 23 patients with
stationary spastic paresis before and after a two-week treatment (45 min daily)
of hydro-kinesi therapy, the latter consisting of passive and active movements in
warm (32 degrees C) sea water, free swimming and water immersion walking. Among
the subjects (80.2 +/- 13.2 kg body mass; 56.0 +/- 14.6 years of age; 10.7 +/-
6.6 years of duration of spasticity), 12 were affected by hemiparesis, 4 by
multiple sclerosis and 7 by spinal cord injury. The energy cost of level walking
(Cw) was measured before and after therapy from the ratio of the overall steady
state oxygen consumption to the effective speed of progression. The differences
in Cw due to the treatment, at matched speeds, were found to be negligible at
speeds higher than 0.75 m.s-1 (less than 5%) but to increase, with decreasing
speed, up to about 17% at 0.1 m.s-1. The treatment was therefore effective in
improving the gait characteristics of the subjects, through a decrease of their
Cw, mainly at low speeds of progression.
PMID- 9764445
TI - Coronary heart disease risk factors in middle-aged former top-level athletes.
AB - A cross-sectional study was conducted to determine the impact of previous
athleticism on coronary heart disease (CHD) risk factors in 168 middle-aged men
and 147 middle-aged women in Estonia. Participants were divided into four groups:
physically active ex-athletes (AA), sedentary ex-athletes (SA), recreational
exercisers (RE), and non-exercisers (NE). The Sharkey's questionnaire was applied
to determine the CHD risk factors, health habits, medical, safety, personal,
psychological and women's risk factors scores. Anthropometric characteristics,
resting systolic and diastolic blood pressure values (SBP, DBP), and physical
working capacity (PWC170) were measured. Concentrations of total cholesterol
(CHOL), high-density lipoprotein cholesterol (HDL-C), triacylglycerols (TG), and
glucose were determined. Low-density lipoprotein cholesterol (LDL-C) and HDL
C/CHOL ratio were computed. From the questionnaire results, significant
differences in CHD risk scores in both sex groups in favour of AA and RE were
found. DBP in men was significantly higher in SA, and SBP in women was
significantly higher in NE in comparison with other groups. PWC170 and PWC170/kg
was highest in AA and lowest in NE in both sex groups. There were no significant
differences for blood biochemical parameters between women's groups. In men, AA
had a lower CHOL level in comparison with SA and NE, and lower concentrations of
TG and LDL-C than other groups. AA and RE had a higher HDL-C concentration and
HDL-C/CHOL ratio in comparison with the other groups. In conclusion, differences
in CHD risk factors were related to current physical activity, and were more
expressed in men than in women.
PMID- 9764446
TI - Effects of walking training on health-related fitness in healthy middle-aged
adults--a randomized controlled study.
AB - The effects of walking training on VO2max, serum lipoproteins and plasma
fibrinogen were studied in 119 healthy middle-aged persons. Training prescription
was 65-75% of VO2max, 50 min/session, four times a week for 15 weeks. The net
difference (between pre-posttraining changes in the walking and control group)
was statistically significant for VO2max (0.14 l .min-1, 95% CI 0.04, 0.23),
total cholesterol (-0.20 mmol.l-1, CI -0.34, -0.06), LDL cholesterol (-0.17
mmol.l-1, CI -0.29, -0.05), ratio of HDL cholesterol to total cholesterol (0.014,
CI 0.005, 0.023), and triglycerides (-0.15 mmol.l-1, CI -0.26, -0.04). No
statistically significant changes occurred in fibrinogen. The findings indicate
that walking training of moderate intensity resulted in a modest increase in
VO2max and minor but consistently favorable changes in serum lipoproteins.
PMID- 9764447
TI - Snapping popliteal tendon as a source of lateral knee pain.
AB - A 25-year-old female patient underwent surgery for a history of pain and popping
on the lateral aspect of her right knee. It was initially thought that the
patient had iliotibial (IT) band syndrome which was refractory to conservative
treatment. However, upon release of the IT band, the snapping which was audible
and palpable pre-operatively was still present. Further exploration of the
posterior-lateral aspect of the knee revealed that the popliteal tendon was
snapping over the incisura poplitea extensoria on the lateral femoral condyle.
Excision of the prominent portion of the articular ridge below the sulcus
popliteus eliminated the snapping sensation. The patient has remained
asymptomatic since surgery for the past 22 months.
PMID- 9764448
TI - Two unconventional testimonies of urolithiasis in the 18th century on the 1600th
anniversary of St. Liborius' death (397-1997)
AB - Urolithiasis can be traced back to periods long past, and its pathological
substrate was well known from the beginning. This knowledge motivated rational,
empirical measures of healing, which included a variety of recipes against
stones. The paper presents two unconventional testimonies of urolithiasis in the
18th century. The Croatian Glagolitic prayerbook from the 18th century is a
valuable source for identification of therapeutical approaches. On the other
hand, a votive painting of Saint Liborius, patron saint against lithiasis,
reflects theurgical views of disease and healing. On the occasion of the 1600th
anniversary of his death, this paper aims to illustrate how his cult was
revitalized in the 18th century.
PMID- 9764449
TI - A few comments on the recipes against kidney stones in the Croatian prayerbook.
PMID- 9764450
TI - Immediate effects of extracorporeal shock waves on the male genital system of
rabbit. Preliminary report.
AB - Hemospermia was reported to occur following extracorporeal shock wave lithotripsy
of lower ureteric stones. Because no studies showed clearly the possible effect
of extracorporeal shock waves (ESW) on the male genital system, we were prompted
to study this effect. Eighteen male white New Zealand rabbits were divided into
three groups (six in each) and subjected to different doses of ESW (2000, 3000
and 4000) using a Dornier MFL 5000. Shocks were focused on the lower parts of the
bladder. Four animals were used as controls. Two hours later, the animals were
dissected. Gross examination of the genital systems showed bleeding in the
testicles and prostates of only some animals, whereas microscopic examination
revealed bloody spots in the genital structures of all animals. The amount of
bleeding was ESW dose-independent. In conclusion, ESW showed evident immediate
effects on the male genital system. Application of shock waves in treating lower
ureteric or vesical stones in doses between 2000 and 4000 may cause bleeding in
the structures of this system, which can lead to hemospermia. More studies will
be needed to show the long-term sequelae of these changes on the male genital
system.
PMID- 9764451
TI - Integrality of benign prostatic hyperplasia tissues after transurethral
thermotherapy evidenced by transmittance fourier transform infrared spectroscopy
combined with thermal analyzer.
AB - Transmittance Fourier transform infrared microspectroscopy combined with
differential scanning calorimetry was used to simulate the clinically
transurethral thermotherapy of benign prostatic hyperplasia (BPH) by in vitro
isothermal determination. The simulative study to the thermotherapy of epithelium
or stroma in BPH tissue was performed at 47 degrees C for 3 h, like clinical
therapy. Whether thermal treatment can induce changes in the secondary structure
of epithelium or stroma in BPH tissue was investigated. The results indicate that
the epithelium and stroma in BPH tissue had different protein secondary
structures, due to the different compositions of the epithelium and stroma. No
significant change was evidenced in secondary structure for each sample either
before or after isothermal study, suggesting the integrality and safety of BPH
thermotherapy in a 47 degrees C for 3 h treatment course.
PMID- 9764452
TI - Effects of phytic acid on renal stone formation in rats.
AB - The effects of phytic acid and phytic acid/zinc mixtures on renal urolith
development in an animal model of nephrolitiasis were studied. Male rats were
divided into four groups of 15, 10, 10 and 12 rats each. The rats of Group I were
treated with ethylene glycol; of Group II with ethylene glycol plus zinc; of
Group III with ethylene glycol phytic acid; and of Group IV with ethylene glycol
plus a mixture of phytic acid/zinc. Urine analysis (24 h) was carried out to
determine the levels of calcium, oxalate, citrate, zinc and phytic acid in each
group. At the end of the experiment all kidneys were removed and examined
macroscopically and microscopically for possible crystal/stone locations and the
total calcium amount in the renal papillary tissue was evaluated. In the rats
treated with the aqueous phytic acid and phytic acid/zinc mixture, the number of
calcifications on the papillary tips and the total calcium amount of the
papillary tissue were significantly reduced compared with the controls treated
exclusively with ethylene glycol or ethylene glycol plus zinc. Consequently,
phytic acid and mixtures of phytic acid/zinc may be a useful agent in the
treatment of patients with calcic urolithiasis.
PMID- 9764453
TI - A randomized prospective study of transurethral electrovaporization vs laser
ablation of the prostate in men with benign prostatic hypertrophy.
AB - OBJECTIVE: A prospective randomized study comparing transurethral
electrovaporization (TVP) vs laser ablation of the prostate was undertaken to
compare the efficacy and safety of the procedures. METHODS: A total of 31
patients underwent treatment, with 20 patients receiving electrovaporization
surgery and 11 patients undergoing laser treatment. Patients underwent initial
evaluation consisting of an American Urological Association (AUA) symptom score,
prostate specific antigen (PSA), uroflowometry, pressure flow, and transrectal
ultrasound for prostate volume. Patients were seen in follow-up at 1, 3 and 6
months. RESULTS: A total of 31 patients with a 2:1 randomization of TVP to laser
treatment were enrolled. The laser patients had a mean pre-operative AUA symptom
score of 19.0 and scores of 9.0, 6.0 and 5.0 at 1-, 3- and 6-month follow-up. The
TVP patients had a mean pre-operative symptom score of 22.0 and scores of 7.0,
8.0 and 5.0 at 1-, 3- and 6-month follow-up. Mean peak uroflow (PF) rate pre
operative was 10.7 for the laser group and 7.7 for the TVP group. At 1-, 3- and 6
month follow-up, mean PF rates of 13.3, 17.6 and 16.5 were present for the laser
patients and 15.0, 17.5 and 14.2 for the TVP group. The differences were not
statistically significant. There were 6 complications in the laser patients and 7
complications in the TVP group. Operative time was a mean of 27 min for the laser
patients and 46 min for the TVP group, and the difference in operative time was
statistically significant. CONCLUSION: At 6-month follow-up the improvement in
symptoms score and peak flow rate are comparable in both treatment groups. The
electrovaporization procedure required significantly longer to perform than the
laser procedure. Long-term follow-up is required to see if these results remain
sustainable for electrovaporization therapy.
PMID- 9764454
TI - Outcome of transurethral prostatectomy in men over 80 years.
AB - Two-hundred-and-twenty-nine men aged between 80 and 97 years (mean 83 years)
underwent transurethral prostatectomy (TUR-P) for lower urinary tract symptoms
(LUTS). All case records were reviewed. The follow-up period was 6-16 years. One
hundred-and-seven patients underwent operation because of acute urinary
retention, and 122 because of chronic retention. The mean weight of tissue
removed was 20 g (1-200 g). The perioperative mortality (< 1 month) was 2% (5
patients). Postoperative complications occurred in 21% (49 patients). Reoperation
was performed in 11% (26 cases). The result was considered satisfactory in 196
patients (86%). The present data demonstrate that transurethral resection of the
prostate in men over 80 years has a good outcome with an acceptable urological
complication rate and mortality, and we therefore advocate surgery instead of
watchful waiting in the fit patient.
PMID- 9764455
TI - Acute epididymitis and urinary tract anomalies in children.
AB - OBJECTIVES: To evaluate the incidence of urinary tract infection (UTI) and
genitourinary malformations in children presenting with acute epididymitis.
PATIENTS AND METHODS: Twenty-five children between 2 months and 14 years of age
presenting with acute epididymitis underwent urine culture, abdominal ultrasound,
voiding cystourethrography and, in selected cases, intravenous pyelography.
Eleven patients were infants and 14 were older than 1 year. UTIs and
genitourinary malformations were recorded. Fisher's exact test was used to
compare the incidence in two age groups. A p value of less than 0.05 was
considered significant. RESULTS: Seven UTIs and eight genitourinary malformations
were diagnosed in infants, while in older children three UTIs and three
malformations were discovered. Infants had a higher rate of associated UTI (p
0.049) and genitourinary malformations (p 0.017) than did older children.
CONCLUSIONS: Our data show a close relationship between acute epididymitis in
infants for both UTIs and genitourinary malformations. Every infant presenting
with epididymitis would undergo a complete evaluation including abdominal
ultrasound and voiding cystourethrography. In older children the need for imaging
should be dictated by clinical history and physical findings.
PMID- 9764456
TI - Effects of ticlopidine in AV-fistula surgery in uremia. Fistula Study Group.
AB - Two hundred and fifty-eight patients with uremia who were offered surgery for
placement of an arteriovenous fistula for hemodialysis were recruited in nine
regional dialysis centers. The patients were randomized to receive the platelet
aggregation inhibitory compound ticlopidine, 250 mg b.d., or matching placebo.
Study medication was targeted at 7, minimum 3, days before scheduled surgery and
continued for 28 days after surgery. The overall rate of occlusion was 41/260
evaluable operations (16%), 25/131 (19%) in the placebo group and 16/129 (12%) in
the ticlopidine group. The risk of early occlusion was a non-significant 35%
lower in the ticlopidine group. Limited risk factor analysis did not clearly
identify any subgroup other than females at greater risk of early thrombosis nor
any subgroup deriving particular benefit from ticlopidine treatment.
PMID- 9764457
TI - Bacteriuria in a population sample of women: 24-year follow-up study. Results
from the prospective population-based study of women in Gothenburg, Sweden.
AB - The aims of the study were to estimate the prevalence of bacteriuria in a female
urban population, to follow up the same population over the years, and to relate
bacteriuria to long-term prognosis with respect to mortality and kidney disease.
The study was based on a randomly selected population sample comprising 1462
women aged 38-60 years at entrance to the study in 1968-69 with an initial
participation rate of 90.1%. Bacteriuria was observed in 3-5%, increasing with
age, and most often asymptomatic. Bacteriuria on one occasion meant increased
risk of having bacteriuria 6 and 12 years later. The percentages of different
types of bacteria and the resistance pattern were similar initially and at follow
up studies after 6 and 12 years. There were no differences in mortality or
incidence of severe kidney disease during a 24-year follow-up between those with
and those without bacteriuria in the baseline study.
PMID- 9764458
TI - Metastasis from renal cell carcinoma to the cervix uteri.
AB - We report on a patient with clear cell adenocarcinoma of the left kidney and a
solitary metastasis to the cervix uteri. Metastases from renal cell carcinoma to
the female genitalia are uncommon and metastatic involvement of the uterus is
very rare. To our knowledge, no more then five cases have been published. A
review of the literature is given.
PMID- 9764459
TI - Vesicouterine fistula twenty years following brachytherapy for cervical cancer.
AB - This report concerns an extremely rare type of fistula, a vesicouterine fistula,
in a 59-year-old female occurring twenty years following brachytherapy for
cervical cancer. The patient presented with a history of recurrent urinary tract
infections, sensation of incompletely emptying the bladder, nocturia and constant
leakage of urine for several months. Cystoscopy revealed a fistulous opening and
an exophytic lesion on the posterior bladder wall. Contrast computerized
tomography demonstrated a fistulous tract between the posterior bladder wall and
the anterior aspect of the uterine cavity. She underwent a hysterectomy, excision
of the bladder fistula and interposition of a vascularized rectus muscle graft.
Histology of the cervix and bladder only revealed inflammatory changes with no
evidence of malignancy. The diagnosis and investigation of this extremely rare
condition are discussed, and the management strategies outlined.
PMID- 9764460
TI - Traumatic renal artery thrombosis.
AB - We report the case of a unilateral traumatic thrombosis of the renal artery.
Revascularization was not performed because the diagnosis was made more than 24 h
after the injury. Early diagnosis and prompt surgical repair are the keys to
successful management of this complication.
PMID- 9764461
TI - Aggressive angiomyxoma of scrotum.
AB - Aggressive angiomyxoma is a rare, locally aggressive but non-metastasizing soft
tissue tumour which occurs almost, exclusively in female pelvic soft tissues. We
report on a tumour occurring in the scrotum of the adult male. Despite a
histologically benign picture, wide excision and strict postoperative control are
recommended because of the risk of tumour recurrence.
PMID- 9764462
TI - [Transsphenoidal hypophysectomy for the treatment of dogs with pituitary
dependent hyperadrenocorticism].
PMID- 9764463
TI - [Serpulina hyodysenteriae infections in swine].
PMID- 9764464
TI - [NCI policy and veterinary medical practice automatization].
PMID- 9764465
TI - [Veterinary medicines supplied directly to breeders].
PMID- 9764466
TI - The optical activity of lysozyme crystals.
AB - The components of the gyration tensor of the enzyme lysozyme were measured by
using the HAUP method: g11 = -0.90 x 10(-5) and g33 = 1.05 x 10(-5) at 303.4 K
and a wavelength of 4880 A. The optical rotatory powers along the a and c axes in
the same conditions were calculated: rho a = -21.3 and rho c = -24.8 degrees cm
1. The optically active property of lysozyme is strange in that, although it
contains a considerable quantity of alpha-helices (about 30%), the rotatory
powers are unexpectedly small in magnitude, one order of magnitude less than
those of quartz and with very large anisotropy. A conceptual consideration of
this phenomenon is given. In order to assess the difference between the
structures in both crystalline and solution states, the chirality index r was
calculated to be 0.16. This value indicates that the structural change of
lysozyme from the solution into the crystalline state is expressed by an increase
of 19% in optical activity. From the NMR results [Smith et al. (1993), J. Mol.
Biol. 229, 930-944], it is anticipated that the r value reflects the increased
constraint in atomic motion in the side chains of exposed amino acid residues in
the crystalline state.
PMID- 9764467
TI - X-ray diffraction by a one-dimensional paracrystal of limited size.
AB - An explicit equation for X-ray diffraction by a finite one-dimensional
paracrystal is derived. Based on this equation, the broadenings of reflections
due to limited size and disorder are discussed. It depicts the paracrystalline
diffraction over the whole reciprocal space, including the small-angle region
where it degenerates into the Guinier equation for small-angle X-ray scattering.
Positions of diffraction peaks by paracrystals are not periodic. Peaks shift to
lower angles compared to those predicted by the average lattice constant. The
shifts increase with increasing order of reflections and degree of disorder. If
the heights and widths of the paracrystalline diffraction are treated as reduced
quantities, they are functions of a single variable, N1/2 g. The width of the
first diffraction depends mostly on size broadening for a natural paracrystal,
where N1/2 g = 0.1-0.2. A method to measure the paracrystalline disorder and size
using a single diffraction profile is proposed based on the equation of
paracrystal diffraction. An initial value of size may be obtained using the
Scherrer equation, that of the degree of disorder is then estimated by the alpha
* law. Final values of the parameters are determined through least-squares
refinement against observed profiles. An equation of diffraction by a
polydisperse one-dimensional paracrystal system is presented for 'box'
distribution of sizes. The width of the diffraction decreases with increasing
breadth of the size distribution.
PMID- 9764468
TI - Mechanism of action and the substrate-dependent pH maximum shift of the alpha
amylase of Bacillus coagulans.
AB - The alpha-amylase of Bacillus coagulans is a saccharifying alpha-amylase which
hydrolyses the disaccharide maltose [L. Keating, C. Kelly, and W. Fogarty,
Biochem. Soc. Trans., 24 (1996) 44S]. The pH maximum for maltose hydrolysis is pH
5.0, differing from the pH maximum for starch hydrolysis which is pH 6.0. Studies
using reducing end 14C-labeled maltooligosaccharides revealed a substrate
dependent pH maximum shift; hydrolysis of radiolabeled maltotriose (G3*) was
maximal at pH 5.0 while the pH maximum for hydrolysis of radiolabeled
maltopentaose (G5*) and maltohexaose (G6*) was pH 6.0. With maltotetraose (G4*)
however, the pH maximum was pH 5.0-6.0. In addition, the bond cleavage pattern of
G4* was dependent on pH. At pH 5.0, the pH maximum for maltose hydrolysis, the
frequency of hydrolysis of the reducing end terminal bond of G4* was maximal.
Determination of the pH maximum of the productive binding modes of the cleavage
patterns of G3* to G6* illustrated the possible role of the occupation of subsite
r + 2 in the pH control mechanism of B. coagulans alpha-amylase.
PMID- 9764469
TI - Evidence for intermolecular binding between deacetylated acetan and the
glucomannan konjac mannan.
AB - Binary mixtures of deacetylated acetan and konjac mannan form thermoreversible
gels under conditions for which the individual components do not gel. Such
synergistic behaviour is normally attributed to intermolecular binding between
the two polysaccharides. X-ray diffraction data obtained from oriented fibres
prepared from deacetylated acetan-konjac mannan gels provides direct evidence for
intermolecular binding between the two polysaccharides. The novel heterotypic
junction zones appear to be six-fold helices with a pitch of 5.6 +/- 0.1 nm.
PMID- 9764470
TI - First analytical chemistry study on drug abuse in the Buenos Aires (Argentina)
University students.
AB - One hundred samples were randomly selected from urine specimens collected from
Buenos Aires University students, 50 males and 50 females, whose ages ranged from
19 to 47 years. Cocaine (COC), cannabinoids (CNNs), amphetamines (AMs),
benzodiazepines (BZDs), barbiturates (BBTs), opiates (OPs) and salicylates (SAs)
were searched for by ELISA, FPIA, normalized TLC, HPLC and GC/MS techniques. The
presence of COC was detected in five samples, CNN in two and SA in twelve. No
evidence of AMs, BZDs, BBTs or OPs was found.
PMID- 9764471
TI - Synthesis of some new biologically active thiadiazolotriazinones.
AB - 4-Amino-6-arylmethyl-3-mercapto-1,2,4-triazin-5(4H)-ones 1 are condensed with
aromatic carboxylic acids, aryloxyacetic acids and anilinoacetic acids 2 to yield
7-substituted-3-arylmethyl-4H-1,3,4-thiadiazolo[2,3-c]-1,2,4-tr iazin-4-ones 3.
Phosphorus oxychloride is used as cyclizing agent. Some of the newly synthesized
compounds are screened for their antibacterial activities.
PMID- 9764472
TI - Synthesis and pharmacological properties of some quinoline derivatives.
AB - A series of 2-(2-thienyl) cinchoninic acids 3, their derivatives 5 and 4-(3
substituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazolo-6-yl)-2-( 2-thienyl)
quinolines 6 were synthesized. The structures of the newly synthesized compounds
are confirmed by analytical, IR, NMR and mass spectral data. The newly
synthesized compounds were evaluated for their anti-inflammatory, analgesic and
anthelmintic activity. The results indicated that dinitrothiophene derivatives 5
are more active.
PMID- 9764473
TI - Glycosidopyrroles. Part 3. Effect of the benzocondensation on acyclic
derivatives: 1-(2-hydroxyethoxy) methylindoles as potential antiviral agents.
AB - The new of 1-(2-hydroxyethoxy)methylindole derivatives 3a-i were prepared in good
yields. None of them showed any significant anti-HIV activity and therefore the
benzocondensation between the 2 and 3 positions of the pyrrole ring definitely
reduced the weak activity found in the analogues 1a-c.
PMID- 9764474
TI - Synthesis of some new benzimidazolecarboxamides and evaluation of their
antimicrobial activity.
AB - A series of 1,2-disubstituted benzimidazole-5(6)-carboxamides was prepared and
evaluated in vitro for antimicrobial activity against Staphyloccus aureus,
Escherichia coli and Candida albicans. The precursor benzimidazolecarboxylic
acids 4a-c and 9a-c were prepared via oxidative condensation of diaminobenzoic
acids with aldehydes and via several steps over the 2(1H)-benzimidazolones,
respectively. All acids were converted to their acyl chlorides with SOCl2, then
amidified with several N,N'-dialkylaminoethyl derivatives. Compounds 8a-c, 20 and
22 exhibited the best activity.
PMID- 9764475
TI - Acute and chronic antiinflammatory effects of plant flavonoids.
AB - The antiinflammatory activities of 30 flavonoids isolated from several plants of
the Compositae family were investigated using carrageenan-induced mouse paw edema
and cotton pellet-induced rat granuloma. Compounds were administered with a
unique dose of 75 mg/kg i.p. in the acute test with carrageenan and 25 mg/kg/day
in the chronic granuloma test. Flavonoids inhibit the development of the induced
granuloma, mostly when a catechol or guaiacol-like B ring is contained in the
compound structure, jaceosidin being the most active flavonoid screened.
Flavonoids significantly inhibited the maximum edema response in the acute test.
We conclude that several of the isolated flavonoids tested here showed
antiinflammatory effects, depending on the experimental model used.
PMID- 9764476
TI - Synthesis and antimicrobial activity of coumarin 7-substituted cephalosporins and
sulfones.
AB - Some coumarin 7-substituted cephalosporins and related sulfones were prepared and
an antimicrobial assay was performed. The minimum inhibitory concentration (MIC)
and minimum bactericidal concentration (MBC) carried out on cephalosporins showed
a potential activity of some of the synthesized compounds against Gram-positive
microorganisms. The tests performed on the corresponding sulfones showed no
significant activity, neither as antimicrobial agents nor as inhibitors of beta
lactamase. An association of sulfone 6a with ampicillin was observed to inhibit
Gram-positive microorganisms with a lower MIC than for ampicillin alone.
PMID- 9764477
TI - Synthesis and biological properties of a new series of N-pyrido substituted
tetrahydrocarbazoles.
AB - A series of methyl and ethyl quaternary pyridiniumtetrahydrocarbazoles was
synthesized and studied in comparison with ellipticine, chosen as a reference. In
general, their antiproliferative activity, tested in different biological
substrates, appeared to be higher than that of the corresponding non
quaternarized compounds. This fact could be attributed to the introduction of a
positive charge in the molecule, which can stabilize the molecular complex they
form with DNA. In a prokaryotic system, the T2 bacteriophage, both quaternarized
and non-quaternarized compounds inhibited its infectivity moderately, in a
similar way to ellipticine. This effect seemed to be connected to a direct
activity on the virions rather than on the indicator bacteria. In mammalian
cells, the pyridiniumtetrahydrocarbazoles were more effective. In particular,
they appeared to be very active in inhibiting DNA synthesis in Ehrlich ascites
cells; some of them were as effective as ellipticine. However,
pyridiniumtetrahydrocarbazoles were less active in comparison with ellipticine
when their capacity for inhibiting the clonal growth in Chinese hamster ovary
(CHO) cells was tested. A similar picture was obtained studying the formation of
chromosome aberrations and of sister chromatid exchanges in the same cells. These
different responses can be explained considering that the data on DNA synthesis
reflect effects only on DNA replication within a short time, without considering
any later consequences; on the contrary, in the long-term tests, other events,
which lead to cell killing or genotoxicity, can take place.
Pyridiniumtetrahydrocarbazoles damage DNA, inducing double-strand breaks
efficiently. These observations, together with the data already obtained on
unsubstituted derivatives, suggest the pyridiniumtetrahydrocarbazoles induce
antiproliferative and genotoxic effects, very probably by inhibiting
topoisomerase II.
PMID- 9764478
TI - Synthesis and aldose reductase inhibitory activity of benzoyl-amino acid
derivatives.
AB - A series of N-(4-methoxy, 4-fluoro, 4-trifluoromethyl and 4-nitrobenzoyl)-L-amino
acids was synthesized and their inhibitory activity towards bovine lens aldose
reductase (ALR2) was tested.
PMID- 9764480
TI - Purification and properties of the 5'-3' exonuclease D10A mutant of DNA
polymerase I from Streptococcus pneumoniae: a new tool for DNA sequencing.
AB - A D10A mutation was introduced at the 5'-3' exonuclease domain of Streptococcus
pneumoniae DNA polymerase I by site directed mutagenesis of the polA gene.
Introduction of the mutation resulted in a drastic decrease of the 5'-3'
exonucleolytic activity present in the wild-type enzyme. Moreover, the mutation
at the D10 residue of the pneumococcal polymerase affected the dependency on
metal activation of its 5'-3' exonucleolytic activity. These results provide
experimental support for the proposed direct involvement of this Asp residue in a
metal-assisted 5'-3' exonucleolytic reaction in type I-like bacterial DNA
polymerases and related bacteriophage 5'-3' exonucleases. The D10A mutant
polypeptide retained the polymerase activity of its parental enzyme, it is able
to incorporate correctly nucleotides in a DNA template, and efficiently uses
labeled and unlabeled nucleotides analogues in DNA sequencing by the dideoxy
chain-termination method. These characteristics convert this polymerase into a
useful tool for manual and automatic sequencing.
PMID- 9764479
TI - Crystallization and stabilization of MB-1, a de novo designed protein for
optimized feeding technology.
AB - Milk Bundle-1 is a de novo protein that was designed for application in
agriculture. It has a high content of selected essential amino acids, and is
intended to adopt an alpha-helical bundle fold. Crystallization experiments with
MB-1 have been carried out on the ground and in reduced gravity on board Columbia
orbiter during mission STS-80. Rather small crystals were obtained (< 0.05 mm) in
both environments. Among other factors, the lack of stability of purified MB-1
has been detrimental to crystal growth. We report here on our progress with
regard to optimizing crystal growth conditions, protein purification and protein
stability. The first MB-1 mutant we present (MB-1-His) contains a poly-histidine
tail, allowing the use of metal affinity chromatography for purification. MB-1
His has been found to keep its original mass for a month at room temperature, a
spectacular improvement over MB-1. The other mutant (MB-1-Cys) was engineered to
carry a cysteine residue on a solvent exposed face. The exposed cysteine binds
readily to p-HMB, and allows for dimerization of MB-1-Cys. The dimer was found to
be twice as stable as MB-1 during proteolytic degradation studies.
PMID- 9764481
TI - Expression of recombinant human acid sphingomyelinase in insect Sf21 cells:
purification, processing and enzymatic characterization.
AB - Biochemical and structural studies on human acid sphingomyelinase (haSMase)
depend on the access to homogeneous biologically active enzyme. Due to the low
abundance of native haSMase (n-haSMase) in human tissue, conventional
purification strategies are not suitable for the isolation of preparative amounts
of the enzyme. We describe a novel approach to the functional expression and
purification of haSMase employing the baculovirus expression vector system.
Infection of Spodoptera frugiperda 21 cells with recombinant baculovirus encoding
haSMase leads to the expression of a glycosylated 75 kDa precursor protein, which
is subsequently processed to an enzymatically active secreted 72 kDa haSMase.
Variations in N-glycosylation and proteolytic maturation account for the
difference in molecular mass between mature recombinant (72 kDa) and human
placental haSMase (75 kDa). N-terminal amino acid sequencing of recombinant
haSMase (r-haSMase) reveals a 23-residue N-terminal extension compared to the
placental enzyme. The apparent K(m) and Vmax values for sphingomyelin degradation
by r-haSMase in a micellar assay system are 32 microM and 0.56 mmol h-1 mg-1,
respectively. In conclusion, the established baculovirus expression vector system
provides an efficient tool for the expression and functional characterization of
haSMase.
PMID- 9764482
TI - Gene expression in the electrically stimulated differentiation of PC12 cells.
AB - Cell differentiation of PC12 cells was electrically induced to grow neurites in
the absence of nerve growth factor (NGF) on the electrode surface, of which
potential was modulated by a rectangular wave of potential. The electric
stimulation induced the c-fos expression which is essential for cell
differentiation. Non-specific calcium channel blocker, lanthanum ion, inhibited
the electrically induced differentiation, while NGF-induced differentiation was
not suppressed. An L-type calcium channel blocker, nifedipine, also inhibited the
electrically induced calcium influx and c-fos expression. Moreover, a stretch
activated (SA) channel blocker, gadolinium ion, inhibited the electrically
stimulated differentiation by blocking the calcium influx, but gave no prominent
effects on the potassium ion-induced differentiation. Chelerythrine, a specific
protein kinase C (PKC) inhibitor, almost inhibited the cell differentiation by
the electric stimulation but not by the NGF treatment. These results indicate
that the alternative potential may stimulate cell differentiation through a PKC
cascade.
PMID- 9764483
TI - Application of an encapsulated filamentous fungus in solubilization of inorganic
phosphate.
AB - Spores of Aspergillus niger were encapsulated in agar, calcium alginate and k
carrageenan and further applied in citric acid production during six repeated
batch cultivations. Rock phosphate (RP) at concentrations of 3 g l-1 and 7 g l-1
was supplemented to the culture medium to test encapsulated-fungus solubilizing
capability. The highest average citric acid productivity of 0.15 g l-1 h-1 was
reached with alginate-bead-encapsulated A. niger on RP-free culture medium while
agar seemed to be the most suitable carrier on RP-supplemented medium.
Accordingly, the highest average soluble P concentration of 0.20 g l-1 batch-1
was obtained with agar-cell beads as compared with other encapsulated systems.
PMID- 9764484
TI - Simultaneous multiple analyte detection using fluorescent peptides and capillary
isoelectric focusing.
AB - Analyte-specific detection based on the isoelectric point of the detection moiety
is a new concept that is under investigation at Vysis. We have developed methods
for the synthesis of of fluorescent synthetic peptides that can be conjugated to
bioanalytes such as nucleic acids and antibodies, processed in a hybridization or
binding assay, and then chemically released prior to detection by capillary
isoelectric focusing (cIEF)-laser-induced fluorescence (LIF) detection. A two
step cIEF method in coated capillaries using salt mobilization has been used that
produces high peak efficiencies and good assay reproducibility. The concentration
by focusing aspect of cIEF, which allows for the entire capillary to be filled
with sample, enables detection limits in the pM as opposed to sub-nM level for
conventional capillary electrophoresis (CE)-LIF. The simultaneous multiple
detection of eleven different focusing entities has been achieved.
PMID- 9764486
TI - Nonaqueous capillary electrophoresis chiral separations with quaternary ammonium
beta-cyclodextrin.
AB - Chiral separation of nonsteroidal anti-inflammatory drugs (profens), 1,1'
binaphthyl-2,2'-diyl-hydrogen phosphate, N-[1-(1-naphthyl)ethyl]phthalamic acid,
and derivatized amino acids by a cationic cyclodextrin, quaternary ammonium beta
cyclodextrin (QA-beta-CD), was investigated by capillary electrophoresis (CE) in
both aqueous and nonaqueous media. Several profens and amino acids could only be
separated by QA-beta-CD in pure formamide system. No chiral separation of the
profens was achieved in the following solvents: N-methylformamide, methanol,
dimethyl sulfoxide, and water; however, chiral separations of most of the amino
acids were obtained in all of these solvents. The effects of other experimental
parameters such as the CD concentration and apparent pH (pH*) were also
investigated. The first application of nonaqueous CE chiral separation of
ketoprofen in a commercially available sample, Actron, was also examined. In
addition, the reversal of electroosmotic flow by QA-beta-CD was observed in
water, formamide, N-methylformamide, methanol, and dimethyl sulfoxide media.
PMID- 9764489
TI - Capillary electrophoretic determination of acetic acid and trifluoroacetic acid
in synthetic peptide samples.
AB - Synthetic peptide samples may contain counter-ions such as acetate or
trifluoroacetate as a result of their method of preparation. Furthermore, because
acetic acid (HOAc) and trifluoroacetic acid (TFA) are frequently used reagents in
peptide synthesis, these acids may be found in synthetic peptide samples as
impurities. This paper describes a method validation to determine HOAc and TFA in
synthetic peptide samples by capillary electrophoresis (CE) using an internal
standard (I.S.) with indirect UV detection. Typical analytical parameters such as
precision, linearity, accuracy, specificity, limit of detection and ruggedness
were evaluated during the validation. In addition, the contents of HOAc and TFA
in two synthetic opioid peptide samples, TIPP[psi] and Orphanin FQ, were
determined using the validated method. A unique feature of the method is that it
offers determination of both acids in a single assay using a common I.S. The
method is very efficient because of relatively short electrophoretic migration
times (typically 2 to 8 min) for the acids investigated. This paper also
discusses the factors that affect precision in a CE assay.
PMID- 9764490
TI - Optimizing separation conditions for proteins and peptides using imaged capillary
isoelectric focusing.
AB - Separation conditions for antibodies, glycoproteins and peptides were optimized
to fully realize the potential of automated imaged capillary isoelectric focusing
(imaged cIEF) for protein analysis. Two commercially available capillary
coatings, polyacrylamide and fluorocarbon, were found to provide reproducible
results for cIEF separations. Both coatings could last more than 100 runs under
normal cIEF conditions. Up to 30 mM salts (Na+) could be added to samples to
prevent protein precipitation before and during isoelectric focusing performed
under imaged cIEF. Short analysis time of the imaged cIEF also aided in the
prevention of protein precipitation. High current at the beginning of the
focusing for samples in salt could be avoided by applying a voltage gradient.
Additions of up to 6 M urea and 20% glycerol could enhance solubility of proteins
and peptide. Imaged cIEF was applied to the quantitation of monoclonal
antibodies.
PMID- 9764491
TI - Motif 2 in adenosine kinase homologous ginseng polypeptide showed affinity to D
ribose by capillary zone electrophoresis and surface plasmon resonance.
AB - Affinity capillary electrophoresis (ACE) and surface plasmon resonance (SPR) were
applied to the analysis of anti-lipolytic acidic tetradecapeptide from Panax
ginseng roots. The ginseng polypeptide (GPP) and modified GPPs were chemically
synthesized and their affinity to D-ribose and adenosine was examined by ACE and
SPR. GPP had affinity to D-ribose and adenosine and the binding constants (Kb) to
GPP were calculated by both methods (Kb = 1.04 x 10(4) mol-1 to D-ribose by ACE
and Kb = 1.91 x 10(4) mol-1 to adenosine by SPR). Most of the modified GPPs lost
their affinity to D-ribose and adenosine through substitution or rearrangement of
the amino acids.
PMID- 9764492
TI - Quantitation of homocysteine in human plasma by capillary electrophoresis and
laser-induced fluorescence detection.
AB - Homocysteine (Hcy) represents a branching point between the transsulfuration and
transmethylation pathway of methionine. A large increase of plasma concentration
of Hcy is observed in patients with inherited hyperhomocysteinemia. A moderated
increase (above 10 microM) is also observed in various pathological conditions,
such as arterial occlusion, hypertension, hyperlipidemia and chronic renal
failure. While amino acids were largely studied using capillary electrophoresis
with UV or laser-induced fluorescence detection (LIF), thiol-amino acids were
not. In this work we present a new approach for testing homocysteine in human
plasma using CE-LIF and fluorescein isothiocyanate. The low fluorescence yield of
the fluorescein thiocarbamyl (FTC) thiol-amino acids limits, probably, the
sensitivity of the detection to 8 x 10(-10) M (instead of 10(-12) M for FTC
arginine).
PMID- 9764493
TI - Determination of the minor whey protein bovine lactoferrin in cheese whey
concentrates with capillary electrophoresis.
AB - In our present work we present the determination of bovine lactoferrin in whey
concentrates as they are typically produced by milk and cheese industry after
production of cheese. Due to the high total protein content the analysis of whey
concentrate samples is difficult and even not possible by using capillary zone
electrophoresis with UV detection. To enhance the detection sensitivity we
applied a more promising approach by using affinity interactions in combination
with laser-induced fluorescence detection. By mixing fluoresceine isothiocyanate
(FITC)-conjugated polyanionic lipopolysaccharide with the mostly positively
charged lactoferrin we found a significant migration time shift which is clearly
dependent on the concentration of the added protein. In the second approach we
developed an immunoassay using FITC-conjugated specific antibody against bovine
lactoferrin. The results of the immunoassay measurements were compared with data
obtained by standard enzyme-linked immunosorbent assay analysis.
PMID- 9764494
TI - Coupling on-line brain microdialysis, precolumn derivatization and capillary
electrophoresis for routine minute sampling of O-phosphoethanolamine and
excitatory amino acids.
AB - In previous papers, we described the analysis of excitatory amino acids (EAAs)
and catecholamines in microdialysis samples using capillary electrophoresis with
laser-induced fluorescence detection (CE-LIFD). In the present paper, we report
that an automated analysis of such samples can be easily achieved by on-line
coupling of the microdialysis probe with a continuous flow derivatization system
and a commercially available CE-LIFD apparatus. Because of the short analysis
time (less than 2 min) and high separation efficiency (100-200,000 theoretical
plates), high temporal resolution of microdialysis (minute range) is preserved as
compared to off-line systems, while both EAAs and O-phosphoethanolamine (PEA) can
be simultaneously detected. This new method has been applied to the measurement
of these compounds in microdialysis samples from hippocampal slice cultures and
striatum of anesthetized rats. Extracellular concentrations of EAAs, but not PEA,
increased during perfusion of a solution containing high K+ or a glutamate uptake
inhibitor. However, after in vitro ischemia on hippocampal slices, both EAAs and
PEA concentrations increased, but with different temporal patterns.
PMID- 9764495
TI - Quantifying biosynthetic human growth hormone in Escherichia coli with capillary
electrophoresis under hydrophobic conditions.
AB - A method has been developed which is able to quantitate the content of precursor
biosynthetic human growth hormone (Pre-bhGH) in the cytosol of E. coli cells
containing the gene for human growth hormone (hGH). The method uses hydrophobic
C18 coated capillaries with native biosynthetic human growth hormone (bhGH) as an
internal standard. This allows for highly robust and precise determinations as
well as the evaluation of the presence of deamidated forms in the cytosol
samples. Furthermore, by modifying the running buffer with zwitterionic
surfactants and an organic modifier, it is possible to detect a related form with
a three sulfur atom Cys-Cys bridge (trisulfide Pre-bhGH). Thus, a strong tool for
monitoring the effect of fermentation conditions on the biosynthesis of bhGH is
obtained.
PMID- 9764496
TI - Cationic and anionic polymeric additives for wall deactivation and selectivity
control in the capillary electrophoretic separation of proteins in food samples.
AB - Both cationic and anionic polymeric additives were used for the capillary
electrophoretic separation of proteins in food samples. The cationic
polyelectrolyte polydiallyldimethylammonium chloride was more effective in
minimizing protein-wall interactions at pH 3 than at pH 7, presumably due to
greater repulsion between the adsorbed polymer and proteins. Improved resolution
was observed in the presence of the co-additive sodium octanesulphonate,
presumably due to ion-pairing interactions with protein sample components. The
anionic polymer dextran sulfate produced relatively high efficiencies, 120,000
180,000 theoretical plates, for protein separation, presumably because the
polymer adsorbed to the capillary wall, rendering the surface more hydrophilic.
In addition to reduced protein-wall interactions, improved resolution was
observed, presumably due to analyte-polymer ion-exchange/ion-pairing
interactions. When poly(vinyl sulphonic acid) was used instead of dextran
sulfate, broader profiles were obtained and fewer components were resolved,
presumably due to reduced wall deactivation that is related to the lower
hydrophilicity of poly(vinyl sulphonic acid).
PMID- 9764498
TI - Asymmetry of protein peaks in capillary zone electrophoresis: effect of starting
zone length and presence of polymer.
AB - The asymmetry of R-phycoerythrin (M(r) = 240,000) peaks in capillary zone
electrophoresis measured as In[(tm-t1)/(t2-tm)], where tm, t1 and t2 are
migration times of the peak mode and at the intersection of the peak width at
half-height with the ascending and descending limbs, respectively, was found to
undergo a transition from negative to positive values with increasing starting
zone length. The transition is compatible with a mathematical model of peak
dispersion which assumes that an interaction of protein with the capillary walls
governs the evolution of the peak during capillary zone electrophoresis. Models
assuming a final peak shape defined solely by longitudinal diffusion, or by a
heterogeneity with regard to mobility or by a conductivity difference between
analyte zone and background electrolyte, have failed to give rise to a change in
the sign of peak asymmetry when the starting zone length is varied. The presence
of polyethylene glycol in the buffer within a concentration range up to 4% does
not appreciably affect the peak asymmetry regardless of whether the concentration
regime is dilute or semi-dilute. Above 4% of polyethylene glycol, the asymmetry
becomes nearly independent of starting zone length, and progressively negative
with increasing polymer concentration. The concentration range at which the
transition from negative to positive asymmetry disappears coincides with that at
which the average mesh size of the polymer network falls below the size of the
protein.
PMID- 9764499
TI - Capillary electrophoretic study of the complex formation between DNA and cationic
surfactants.
AB - Due to the growing interest in the use of cationic surfactants for the
construction of liposomal genetic delivery systems, the study of complex
formation between DNA and quaternary ammonium detergents is of fundamental
importance. In this context, we undertook the study of this complex formation
using capillary zone electrophoresis (CZE) with suppressed electroosmotic flow, a
technique that allowed us to both monitor the change in mobility of DNA as a
function of added surfactant in a precise and reproducible manner and evaluate
the potential of CZE to reflect the change in hydrodynamic friction upon binding.
Nevertheless, CZE must be applied with caution for binding studies where strong
cooperativity occurs, because of the presence of peak splitting at concentrations
close to the half-point of binding. Also, a comparison between this experiment
and Manning's polyelectrolyte transport properties theory on one hand and Tirado
and Garcia de la Torre expression for hydrodynamic friction of rod-like molecules
on the other hand is given.
PMID- 9764500
TI - Simultaneous analysis of various mutations on the 21-hydroxylase gene by multi
allele specific amplification and capillary gel electrophoresis.
AB - A detailed study is presented on the detection of various known point mutations
using polymerase chain reaction (PCR) based multi-allele specific amplification
(MASA) in conjunction with capillary gel electrophoresis (CGE) separation. The
resulting PCR products, corresponding to the individual mutations, are labeled
with ethidium bromide during CGE separation, and detected by laser-induced
fluorescence. MASA proved to be a novel, fast and cost-effective method for
simultaneous analysis of multiple known mutation sites, employing more than one
allele specific primers in a single PCR reaction. It results in coexisting
amplification of numerous DNA fragments differing in size, which are subsequently
separated by CGE. In the present study, several point mutations were analyzed
simultaneously by MASA-CGE on the 21-hydroxylase gene of a patient with
congenital adrenal hyperplasia.
PMID- 9764501
TI - Pluronic copolymer liquid crystals: unique, replaceable media for capillary gel
electrophoresis.
AB - Liquid crystalline solutions of Pluronic copolymers are versatile alternatives to
solutions of entangled, random coil polymers as replaceable media for capillary
gel electrophoresis (CGE). Pluronic copolymers are tri-block polymers of
poly(ethylene oxide) [(EO)x] and poly(propylene oxide) [(PO)y] with the general
formula (EO)x(PO)y(EO)x. Large micelles form in aqueous solutions in which
central, hydrophobic cores of (PO)y segments are surrounded by "brushes" of
hydrated (EO)x tails. Solutions of Pluronic F127 (BASF Performance Chemicals) in
a concentration range of about 18-30% are liquids at refrigerator temperatures (<
or = 5 degrees C) and are easily introduced into capillaries. A self-supporting,
gel-like liquid crystalline phase is formed as the temperature is raised to > or
= 20 degrees C. This liquid crystalline phase consists of spherical micelles with
diameters of 17-18 nm which pack with local cubic symmetry. CGE in Pluronic F127
liquid crystals separates species within several chemical classes as varied as
nucleoside monophosphates and organic dyes, oligonucleotides of 4-60 nucleotides,
DNA fragments of 50-3000 base pairs (bp), and supercoiled plasmid DNAs of 2000
10,000 bp. Mechanisms of molecular sieving in polymer liquid crystals must differ
in fundamental ways from separations in random polymer gels because molecules
move around uncrosslinked obstacles that are larger than the smallest dimensions
of typical analytes. Molecular sieving in Pluronic liquid crystals is envisioned
to occur as molecules squeeze between hydrated (EO)x strands of micelle brushes,
or through brushtips and interstitial spaces between micelles. Small molecules
such as nucleotides appear to separate by a different mechanism involving
partitioning between hydrophilic and hydrophobic environments. This process is
termed "hydrophobic interaction electrophoresis". The unique structures of
Pluronic copolymers and their liquid crystalline phases provide new challenges
and opportunities in separations science.
PMID- 9764502
TI - Quality control of pentosane polysulfate by capillary zone electrophoresis using
indirect detection.
AB - Pentosane polysulfate sodium salt (PPS) is a mixture of multiply charged anionic
polysaccharides, used for urological treatment. Several constituents of the
polysaccharide can be characterized by a highly reproducible fingerprint. In
comparison with earlier approaches the separation efficiency has been further
improved using an anionic benzene-1,2,4-tricarboxylic acid buffer (8.7 mmol l-1,
pH = 4.9) with indirect UV detection (lambda = 217 nm) and a special capillary
pretreatment (1 M NaOH for 10 h at 25 degrees C applying -20 kV). The method has
been optimized with regard to buffer concentration and pH. The robustness was
tested on several capillaries. PPS was separated from all major synthetic
impurities such a sulfate, chloride and acetate. Twelve PPS batches from two
manufactures were measured and compared.
PMID- 9764503
TI - Development of an on-line preconcentration method for the analysis of pathogenic
lipopolysaccharides using capillary electrophoresis-electrospray mass
spectrometry. Application to small colony isolates.
AB - The present investigation describes the use of on-line chromatographic
preconcentration coupled to capillary zone electrophoresis-electrospray mass
spectrometry (cPC-CZE-ES-MS) for trace level analysis of negatively charged
lipopolysaccharides (LPS) obtained from pathogenic strains of Haemophilus
influenzae. The analytical performance of two different types of adsorption media
[i.e., C18 irregular particles and poly(styrene-divinylbenzene) membrane] for
anionic analytes was first evaluated using a mixture of peptide standards to
determine the overall sensitivity of this approach. These chromatographic
preconcentrators provided an enhancement of sample loadings of up to 5
microliters with good linear response and low nM concentration detection limits
for most peptides investigated. The application of cPC-CZE-ES-MS is further
demonstrated for extracts of O-deacylated LPS obtained from H. influenzae strain
Eagan. In combination with novel enzymatic releasing methods using proteinase K,
this technique provides unparalleled sensitivity and enabled the identification
of LPS surface antigens from as little as five bacterial colonies.
PMID- 9764504
TI - Determination of allantoin in biofluids using micellar electrokinetic capillary
chromatography.
AB - A micellar electrokinetic chromatographic method is described for the
determination and quantitation of allantoin, an end-product of purine metabolism
in mammals that is applicable to biofluids of different mammal species and man.
The method was optimised following a study on the effect of pH and sample
preparation procedure. Final conditions were 30 mM sodium tetraborate, pH 9.5, 75
mM sodium dodecyl sulphate, 20 kV and 20 degrees C. Allantoin was well resolved
from endogenous compounds and could be determined in horse, dog, mouse and rabbit
urine. No allantoin could be found in man. No complicated sample treatment was
necessary, thus the developed method was rapid (< 5 min), sensitive (5 microM)
and simple. Results from this work will permit the determination of allantoin in
man as a measure of free radical generation reactions as well as its presence in
the plasma and other biofluids with modification of the sample preparation
procedures.
PMID- 9764505
TI - Capillary electrophoretic study of individual exocytotic events in single mast
cells.
AB - In this work we have demonstrated the application of on-column dynamic release of
serotonin from individual granules within rat peritoneal mast cells (RPMCs).
These granules are approximately 0.25 fl in volume and represent some of the
smallest entities studied by capillary electrophoresis (CE). With the coupling of
high-speed CE and laser-induced native fluorescence, a time resolution of 0.002
min and a detection limit of 0.9 amol (S/N = 3, rms) were achieved. By using a
secretagogue as the running buffer for CE, we resolved the peak profile of
individual degranulation events released due to exocytosis. The average amount of
serotonin released for five RPMCs analyzed was 33 amol +/- 16%.
PMID- 9764506
TI - Electrochemical analysis of clinical blood-gases, gases and vapours.
AB - This tutorial review charts the development of electrochemical sensors for the
analysis of blood-gases, gases and vapours in clinical medicine over the past
four decades. The development of each sensor is set in its historical and
clinical context, and the first part of the review concentrates on aqueous
electrolyte electrochemistry and on those sensors which have made a major impact
on the clinical measurement of the partial pressures of oxygen and carbon dioxide
in the blood. The electrochemical interference effects of anaesthetic agents on
these measurements are also described. Those electrochemical sensors which have
failed, in the past, to make a clear impact in this area are not considered, but
the few attempts to devise aqueous electrolyte electrochemical sensors for
anaesthetic agent measurement are reviewed. The second part of the review
describes the chequered history of the development of non-aqueous solvent
electrochemical sensors to measure the partial pressures of oxygen and carbon
dioxide, in both the presence and absence of each other, in the gas phase. The
last part of the review examines various attempts, using non-aqueous solvent
electrochemistry, to measure the concentration of inhalational anaesthetic
vapours in the gas phase. These sensors have yet to make an impact on clinical
practice. Throughout this tutorial review, theoretical models of membrane-covered
electrochemical sensors are described where appropriate. This review represents a
personal view of the development of electrochemical sensors for clinical
measurement, and it is therefore necessarily selective in its approach and
emphasis.
PMID- 9764507
TI - Determination of total mercury in biological tissues by flow injection cold
vapour generation atomic absorption spectrometry following tetramethylammonium
hydroxide digestion.
AB - A simple, rapid and reliable method was developed for the determination of total
mercury in biological samples. Samples were solubilized using tetramethylammonium
hydroxide (TMAH). The organically bound mercury was cleaved and converted to
inorganic mercury by on-line addition of KMnO4. The decomposed mercury together
with inorganic mercury originally present in samples was determined by flow
injection cold vapour atomic absorption spectrometry after reduction to elemental
mercury vapour using NaBH4. A sample throughput of 100 measurements per hour was
achieved after a 30 min dissolution with TMAH. The relative standard deviation
for 20 micrograms l-1 Hg was 1.3% (n = 11) and the limit of detection was 0.1
microgram l-1 (3 sigma). The proposed method was validated by the analysis of a
suite of certified marine biological reference materials, DORM-2 (dogfish
muscle), DOLT-2 (dogfish liver) and TORT-2 (lobster hepatopancreas), with
calibration against simple HgII standards.
PMID- 9764508
TI - Determination of tylosin residues in pig tissues using high-performance liquid
chromatography.
AB - In accordance with the maximum residue limit of 100 micrograms kg-1 established
by EU legislation, a simple and sensitive high-performance liquid chromatographic
(HPLC) method was developed for the measurement of tylosin residues in pig
tissues (fat, kidney, liver and muscle). Tylosin, a macrolide antibiotic, is
extracted with water-methanol and cleaned-up by solid-phase extraction (SPE) on
cation-exchange cartridges using methanol elution. Tylosin was determined by
reversed-phase HPLC with UV detection at 280 nm and the mean recovery from pig
tissues fortified in the range 50-200 micrograms kg-1 was 70-85%, with intra- and
inter-day RSDs in the ranges 3.4-9.1 and 3.9-10.1% respectively.
PMID- 9764509
TI - Expression immunoassay based on antibodies labeled with a deoxyribonucleic acid
fragment encoding the alpha-peptide of beta-galactosidase.
AB - An immunoassay is reported which uses, as a label, an expressible DNA fragment
encoding the alpha-peptide of beta-galactosidase. This inactive peptide consists
of 97 amino acid residues containing an amino-terminal portion of the enzyme.
Antigen (an anti-thyrotropin immunoglobulin) immobilized in microtiter wells is
allowed to react with specific antibodies which are then linked to the DNA label
via biotin-streptavidin interaction. After completion of the immunoreaction, the
solid phase bound DNA is subjected to a cell-free, one-step
transcription/translation reaction to produce the alpha-peptide. The alpha
peptide is allowed to react (complementation reaction) with the remaining part of
the beta-galactosidase (M15 protein, also inactive) to give fully active enzyme
molecules. 4-Methylumbelliferyl galactoside is used as a substrate. The
fluorescence is linearly related to the amount of antigen in the well. As little
as 3 fmol of antigen can be detected. The RSDs (within-run) obtained for 8 and 20
fmol of antigen were 10.7 and 9.3%, respectively (n = 4). The present work
illustrates the utility of expressing a non-detectable peptide capable of
triggering a signal generating system.
PMID- 9764510
TI - Sandwich-type deoxyribonucleic acid hybridization assays based on enzyme
amplified time-resolved fluorometry.
AB - We report microtiter well-based sandwich-type DNA hybridization assays using
enzyme amplified time-resolved fluorometry of Tb3+ chelates. The target DNA was
hybridized with two adjacent and non-overlapping oligonucleotide probes, one
oligonucleotide serving as the capture probe and the other as the detection
probe. Two ligand-specific binding protein pairs were used alternately for
capture of the hybrids to the solid phase and detection; the biotin-streptavidin
and the digoxigenin-anti-digoxigenin interaction. In both cases, alkaline
phosphatase was used as a reporter molecule and diflunisal phosphate as a
substrate. The catalytic hydrolysis of the substrate produces diflunisal which
forms ternary fluorescent complex with Tb(3+)-EDTA. Furthermore, we studied the
effect of the probe labeling method and the position of the label on the
sensitivity of the assays. The data suggest that capture of the hybrids through
biotin-streptavidin and detection via digoxigenin-anti-digoxigenin offer 2-3
times higher sensitivity than the reverse configuration. The highest sensitivity
was achieved with enzymatic labeling of capture and detection probes at the 3'
end. A signal-to-background ratio of 4 was achieved for 0.2 fmol of target DNA.
The RSD were better than 4%.
PMID- 9764511
TI - Development of a biparametric bioanalyser for creatinine and urea. Validation of
the determination of biochemical parameters associated with hemodialysis.
AB - The construction and evaluation of an automated urea and creatinine biparametric
biosystem using flow injection analysis (FIA) are described. The biosystem uses
enzyme reactions that hydrolyse urea and creatinine producing ammonium ions. The
enzymes used were creatinine deiminase and urease, which are immobilized
covalently in flow reactors. The reactor with creatinine deiminase has the enzyme
immobilized on controlled-pore glass beads, whereas urease is immobilized on a
nylon open tubular reactor. Detection is realised with a flow-through ammonium
ion-selective electrode with an inner solid-state contact (graphite-epoxy
composite). Ammonium ions are separated from alkali ion interferents through a
gas-diffusion cell. The bioanalyser is fully automated using software and
electronics developed ex profeso in our laboratories. The analyser was validated
off-line by measuring urea and creatinine from discrete effluent samples from
hemodialysis equipment. Results agreed with concurrent analyses realised using
hospital laboratory methods. There were no significant differences between the
two sets of results at the 95% confidence level. Finally, the biparametric
bioanalyser was validated on-line by measuring creatinine and urea levels in
artificial kidney effluents. These measurements were useful in the determination
of key biochemical parameters of clinical interest such as the mass of urea and
creatinine extracted from the patient as well as the initial concentration of
creatinine and urea in blood plasma. When the results of the bioanalyser were
compared with those yielded by the usual methods, they showed no significant
differences at the 95% confidence level when determining the mass of the analytes
extracted by the hemodialyser or when determining the urea concentration in blood
plasma. However, when measuring the creatinine concentration in blood plasma
using the developed bioanalyser, significant differences appeared.
PMID- 9764512
TI - Liposome immunoassay by long-lived fluorescence detection.
AB - Immunoassay by fluorescence energy transfer from a europium chelate in liposome
to allophycocyanin (APC) was demonstrated. Streptavidin or antibody to biotin was
bonded to the liposome containing the europium chelate of 2
naphthoyltrifluoroacetone in the bilayer. When the biotin bonded to APC (APC-BT)
was added to the prepared liposomes and the long-lived fluorescence (lambda ex
336 nm, lambda em 665 nm, delay time 0.05 ms, gate time 3.9 ms) was measured by a
flow system, the fluorescence energy of the europium chelate was found to be
transferred to APC-BT and the long-lived fluorescence intensity to increase
linearly as the concentration of APC-BT (1-10 micrograms ml-1) increased.
Further, the intensity decreased competitively with the concentration of biotin
(0.1-100 microM) when biotin was added to the liposome solution containing a
constant concentration of APC-BT.
PMID- 9764513
TI - Electrooxidation of thiocyanate on the copper-modified gold electrode and its
amperometric determination by ion chromatography.
AB - Cyclic voltammetry was used to investigate the electrochemical behavior of an
Au/Cu electrode towards the electrooxidation of thiocyanate ion in alkaline
medium. The effects of pH, copper loading, scan rate and applied potential on the
electrocatalytic oxidation of thiocyanate have been investigated. Flow injection
experiments and ion-chromatography (IC) were performed to characterise the
electrode as an amperometric sensor for the thiocyanate determination. The
effects of carbonate concentration and common interferents on the retention time
were also estimated. The electrode stability, precision, limit of detection and
linear range were evaluated at a constant applied potential of 0.7 V vs. Ag/AgCl.
Calibration plots, obtained in IC, were linear from 1.0 to 195 microM
(correlation coefficient of 0.9984). The detection limit (LOD) was 0.5 microM (29
ppb) in a 50 microlitres injection. An example of analytical application, which
includes the IC separation and detection of thiocyanate ion present in human
urine, is given.
PMID- 9764514
TI - Determination of the pH difference across a cell membrane using a methylammonium
selective membrane electrode.
AB - A method was developed for determining pH differences across cell membranes using
a methylammonium-selective membrane electrode, based on monitoring of the pH
gradient-induced uptake of methylammonium in situ. The methylammonium electrode
was constructed using calix[6]arene-hexaacetic acid hexaethyl ester as a neutral
carrier and bis(2-ethylhexyl) sebacate as a membrane solvent in a poly(vinyl
chloride) membrane matrix. This electrode exhibited a near-Nernstian response to
methylammonium in the concentration range 2 x 10(-5)-1 x 10(-2) M with a slope of
58 mV per concentration decade in a buffer solution of 150 mM choline chloride-10
mM TRIS-HCl (pH 7.5). The limit of detection was 5 x 10(-6) M. In experiments
using liposomes, the uptake of methylammonium into liposomes occurred effectively
when the pH of the outside suspension medium was alkaline, and the determination
of changes in methylammonium concentrations in the outer medium was
quantitatively related to changes in the pH differences across the liposomal
membrane. The transmembrane pH differences in Escherichia coli cells were also
determined by this method.
PMID- 9764515
TI - Development of a method for the determination of low contents of asbestos fibres
in bulk material.
AB - Asbestos is a category 1 carcinogen under the EU classification, but in the
absence of a method to quantify asbestos in a matrix at the 0.1% level, there has
been a delay in implementing relevant directives to asbestos. An analytical
scheme for identification and quantification of asbestos using polarised light
microscopy (PLM) and phase contrast optical microscopy (PCM) has now been
developed. When used on artificial mixtures by an experienced laboratory, it
achieved the required target performance, at 0.1% asbestos concentration by mass
in a bulk sample, to obtain a result, which with 90% probability, is correct
within a factor of two. The method of identification by PLM and quantification by
PCM has been assessed by interlaboratory comparisons. The method begins with an
initial identification using PLM, and depending on asbestos type and matrix a
combination of preparation procedures are used to produce the analytical filter.
A gentle comminution method was used which reduces the risk of overmilling. The
asbestos mass percentage on the filter is quantified using PCM in combination
with a PLM attachment for identification of possible non-asbestos fibres. The
final method is supported by efficient methods for fibre identification for size
determination and calculation of total fibre volume. A statistical analysis of
mass concentration estimates was made and the effect of preferred orientation of
fibres on the analytical filter was quantified.
PMID- 9764516
TI - The medical film 1897-1997: Part I. The first half-century.
AB - Medicine has frequently been in the forefront of applying new illustrative media
to its needs, and cinematographic film is a good example. Within a year of the
introduction of moving pictures, cine-film was used for medical research and to a
lesser extent for teaching. The profession took advantage of the spread of
cinemas by making health education films, and during the first half century of
cinematography surgeons were keen to have their operations filmed. Medical
educators were slow to include film in their teaching programmes and several
organizations were formed to encourage their use. After the Second World War,
medical films for undergraduate and postgraduate education became accepted until,
as the medical film reached its centenary, cine-film declined in favour of video
recordings.
PMID- 9764517
TI - Planning and producing scientific posters.
AB - Poster sessions now form an important part of most scientific and medical
meetings. Traditionally they have been seen by presenters as the poor relation to
the lecture programme and consequently poster preparation has never been given
the attention it deserves. This article examines the principles of poster
production and describes the contribution the illustrator can make to its
production.
PMID- 9764518
TI - Large format ink-jet poster production: a case report.
AB - To complement the services offered by the Medical Illustration Department of
Frenchay Hospital, Bristol, we decided to look at the possibility of producing
posters using the ink-jet process. Our designers wanted to use the full scope of
their computers and software to expand their design talents. The method of
cutting and pasting sheets of paper onto card seemed old fashioned and denied
clients the benefit of the exciting techniques that have become available. After
seeking sponsorship, a drug company gave 8000 Pounds towards setting up the
department's poster printing service. A Kodak DS1000 printer was installed
together with Posterjet and Posterworks software and we went into production,
servicing not only our hospital but others in the area who gave their support for
the service. High quality photographic reproduction was achieved and clients and
consultants were very pleased with the results. The designers were happy that
their skills were being used and interest in this and other services in the
department have increased. The resulting increased income has helped finance
other projects. The printer has enabled us also to see output proofs before
sending work off to be offset printed--a very useful tool and a cost-saving
process.
PMID- 9764519
TI - 2000 and out? Computers and the 'millennium time bomb'.
AB - So what is all this fuss about computers and the year 2000? Is it really a
doomsday scenario? How will it affect us? This short article seeks to explain the
problem and its significance to the medical illustration profession.
PMID- 9764520
TI - Making and using visual and audio recordings of patients. General Medical
Council.
PMID- 9764521
TI - The cone/horizontal cell network: a possible site for color constancy.
AB - Color vision is spectrally opponent, suggesting that spectrally opponent neurons,
such as the horizontal cells in fish and turtle retinae, play a prominent role in
color discrimination. In the accompanying paper (Kraaij et al., 1998), it was
shown that the output signal of the horizontal cell system to the cones is not at
all spectrally opponent. Therefore, a role for the spectrally opponent horizontal
cells in color discrimination seems unlikely. In this paper, we propose that the
horizontal cells play a prominent role in color constancy and simultaneous color
contrast instead of in color discrimination. We have formulated a model of the
cone/horizontal cell network based on measurements of the action spectra of the
cones and of the feedback signal of the horizontal cell system to the various
cone types. The key feature of the model is (1) that feedback is spectrally and
spatially very broad and (2) that the gain of the cone synapse strongly depends
on the feedback strength. This makes the synaptic gain of the cones strongly
dependent on the spectral composition of the surround. Our model, which
incorporates many physiological details of the outer retina, displays a behavior
that can be interpreted as color constancy and simultaneous color contrast. We
propose that the horizontal cell network modulates the cone synaptic gains such
that the ratios of the cone outputs become almost invariant with the spectral
composition of the global illumination. Therefore, color constancy appears to be
coded in the retina.
PMID- 9764522
TI - Spectral sensitivity of the feedback signal from horizontal cells to cones in
goldfish retina.
AB - The spectral sensitivity of cones in isolated goldfish retina was determined with
whole-cell recording techniques. Three spectral classes of cones were found with
maximal sensitivities around 620 nm, 540 nm, and 460 nm. UV-cones were not found
because our stimulator did not allow effective stimulation in the UV range. The
spectral sensitivity of the cones closely matched the cone photopigment
absorption spectra at the long wavelength side of the spectrum, but deviated
significantly at shorter wavelengths. Surround stimulation induced an inward
current in cones due to feedback from horizontal cells. The spectral sensitivity
of this feedback signal was determined in all three cone classes and found to be
broader than the spectral sensitivity of the cones recorded from, and to be
spectrally nonopponent. These data are consistent with a connectivity scheme
between cones and horizontal cells in which the three horizontal cell systems
feed back to all cone systems and in which all horizontal cell systems receive
input from more than one cone system.
PMID- 9764523
TI - Noise removal at the rod synapse of mammalian retina.
AB - Mammalian rods respond to single photons with a hyperpolarization of about 1 mV
which is accompanied by continuous noise. Since the mammalian rod bipolar cell
collects signals from 20-100 rods, the noise from the converging rods would
overwhelm the single-photon signal from one rod at scotopic intensities
(starlight) if the bipolar cell summed signals linearly (Baylor et al., 1984).
However, it is known that at scotopic intensities the retina preserves single
photon responses (Barlow et al., 1971; Mastronarde, 1983). To explore noise
summation in the rod bipolar pathway, we simulated an array of rods synaptically
connected to a rod bipolar cell using a compartmental model. The performance of
the circuit was evaluated with a discriminator measuring errors in photon
detection as false positives and false negatives, which were compared to
physiologically and psychophysically measured error rates. When only one rod was
connected to the rod bipolar, a Poisson rate of 80 vesicles/s was necessary for
reliable transmission of the single-photon signal. When 25 rods converged through
a linear synapse the noise caused an unacceptably high false positive rate, even
when either dark continuous noise or synaptic noise where completely removed. We
propose that a threshold nonlinearity is provided by the mGluR6 receptor in the
rod bipolar dendrite (Shiells & Falk, 1994) to yield a synapse with a noise
removing mechanism. With the threshold nonlinearity the synapse removed most of
the noise. These results suggest that a threshold provided by the mGluR6 receptor
in the rod bipolar cell is necessary for proper functioning of the retina at
scotopic intensities and that the metabotropic domains in the rod bipolar are
distinct. Such a nonlinear threshold could also reduce synaptic noise for
cortical circuits in which sparse signals converge.
PMID- 9764525
TI - Analysis of the postnatal growth of visual cortex.
AB - Development and growth of V1 begins during embryogenesis and continues
postnatally. The growth of V1 has direct implications on the organization of
features such as the retinotopic map and the pattern of visual cortical columns.
We have examined the postnatal growth and two-dimensional shape of V1 in macaque
monkeys, cats, and rats. The perimeter, area, and anterior-posterior length of V1
were measured from unfolded and flattened sections from neonatal and adult
animals from each of these species. Although there were substantial differences
in the overall amount of postnatal growth, from 18% in macaque monkeys to more
than 100% in cats, in all three species the shape of V1 did not change during
development. Thus, growth of the mammalian visual cortex is well described as an
isotropic expansion, so the layout of the global features, such as the
arrangement of ocular dominance columns and the retinotopic map, does not need to
change during development. Furthermore, quantification of the shape confirms the
observations that there is a similar, egg-like oval shape to the visual cortex of
these mammalian species.
PMID- 9764524
TI - Developmental expression of the rat rod photoreceptor cGMP-gated cation channel.
AB - The appearance of cGMP-gated cation channel protein in the postnatal rat retina
has been studied by fluorescence immunocytochemistry of radial retinal sections
and immunoblots of retinal membrane proteins. Channel immunoreactivity was first
detectable with RCNGC1-7H2 monoclonal antibody at postnatal day 7 (PN7) by both
methods. Immunocytochemical label in retinal sections was localized to the outer
segments, and immunoreactivity increased with increasing age. We also compared
the developmental appearance of the cGMP-gated cation channel to that of other
phototransduction proteins and developmental markers. RET-P2, a monoclonal
antibody recognizing the 39-kDa rds/peripherin disc protein, first labeled outer
segments at PN7, coincident with cGMP-gated cation channel expression. Double
labeling of the same section of PN7 rat retina with RET-P2 and R309 (a polyclonal
antiserum against the rod cGMP-gated cation channel) revealed identical patterns
of labelling. Similarly, double labeling with RCNGC1-7H2 and an antibody against
the rod cGMP-phosphodiesterase gave coincident labeling, suggesting coordinate
expression mechanisms of phototransduction proteins with each other and with
outer segment structural proteins.
PMID- 9764526
TI - Increased absolute light sensitivity in Himalayan mice with cold-induced ocular
pigmentation.
AB - Controversy over the relationship between ocular pigmentation and absolute dark
adapted light sensitivity has persisted for over two decades. Previous
electrophysiological experiments in hypopigmented mammals (mice, rats, rabbits)
show increased thresholds in the dark-adapted state proportional to the deficit
in ocular melanin. Animals with the least amount of ocular melanin have the most
elevated thresholds. Dark-adapted thresholds in hypopigmented mice show similar
threshold elevations in behavioral tests. The present study extends these
findings to show that a specific increase in ocular pigmentation results in the
converse effect, lowered absolute dark-adapted thresholds. The increase in ocular
melanin was accomplished by keeping Himalayan mice in the cold (4 degrees C) for
6 weeks. Himalayan mice (C57BL/6J cH/cH) were compared to black mice (C57BL/6J
(+/+)) and albino mice (C57BL/6J c2J/c2J) after 6 weeks at either 4 degrees C or
20 degrees C in 12-h cycling light (<1 cd/m2). The Himalayan mice that were kept
in the cold exhibited a 44% increase in ocular melanin compared to Himalayan mice
kept at room temperature. Cold rearing did not effect ocular melanin or visual
thresholds in control animals (black mice = 10(-5.9) cd/m2 and albino mice = 10(
4.4) cd/m2). In contrast, the Himalayan mice maintained at 4 degrees C had
thresholds of 10(-5.7) cd/m2 compared to 10(-5.1) cd/m2 for Himalayan mice kept
at 20 degrees C. This represents compelling evidence of a direct relationship
between ocular melanin concentration and absolute dark-adapted light sensitivity.
PMID- 9764527
TI - Zebrafish visual sensitivity is regulated by a circadian clock.
AB - We have recently developed a behavioral assay, based on the escape response of
fish to a threatening object, to analyze quantitatively the visual sensitivity of
zebrafish. During the course of dark adaptation, we measure the threshold light
intensity required to evoke an escape response. Under a normal light-dark (LD)
cycle, thresholds for both the cone and rod systems are considerably lower in
late afternoon hours than in early morning hours. Over a period of 24 h,
zebrafish are most sensitive to visual stimuli prior to light off and least
sensitive prior to light on. Under conditions of constant illumination, this
rhythm of visual sensitivity persists for several days but is gradually lost. In
constant light (LL), the rhythm persists 1-2 days; thereafter, visual thresholds
at all times of the day converge at a level similar to thresholds measured in
late afternoon hours in control animals. In constant darkness (DD). the rhythm
persists at least 5 days; thereafter, it dampens to a level about a half-log unit
less sensitive to that measured in the late afternoon hours in control animals.
These data suggest that visual sensitivity in zebrafish is regulated by an
endogenous circadian clock which functions to decrease the visual sensitivity.
PMID- 9764528
TI - Spectral sensitivity of the goldfish Torus longitudinalis.
AB - We measured the photopic spectral sensitivity of multiunit activity in the torus
longitudinalis and optic tectum of goldfish. Since negative contrast stimuli are
most effective for exciting torus longitudinalis, spiking activity was evoked by
the shadow of a disc moving through a monochromatic light beam projected upon a
screen. The amount of activity evoked in torus longitudinalis generally increased
with the monochromatic stimulus radiance at the same rate for all wavelengths,
indicating a univariant response. Spiking activity in tectum, however, increased
at different rates across the spectrum, indicating color-dependent responses. The
action spectra for torus longitudinalis were all similar and relatively flat as
expected of a homogeneous, broad-band luminance processing system, and about 1
log unit more sensitive than the tectal action spectra. The latter generally
displayed sharp peaks and dips in sensitivity indicative of opponent processing.
PMID- 9764529
TI - Soluble guanylate cyclase and nitric oxide synthase in synaptosomal fractions of
bovine retina.
AB - Cyclic GMP has been shown in recent years to directly activate ion channels in
bipolar and ganglion cells, and to indirectly regulate coupling between
horizontal cells, and between bipolar and amacrine cells. In all of these cases,
the effects of cyclic GMP are mimicked by nitric oxide. An increase in calcium
concentration stimulates the production of nitric oxide by neuronal and
endothelial forms of nitric oxide synthase, which in turn activates soluble
guanylate cyclases, enhancing the synthesis of cyclic GMP. Though some effects of
nitric oxide do not involve cyclic GMP, the nitric oxide-cyclic GMP cascade is
well recognized as a signaling mechanism in brain and other tissues. The
widespread occurrence of nitric oxide/cyclic GMP-regulated ion channel activity
in retinal neurons raises the possibility that nitric-oxide-sensitive soluble
guanylate cyclases play an important role in cell-cell communication, and
possibly, synaptic transmission. Immunohistochemical studies have indicated the
presence of soluble guanylate cyclase in retinal synaptic layers, but such
studies are not suitable for determination of the density or quantitative
subcellular distribution of the enzyme. Microanalytical methods involving
microdissection of frozen retina also showed the presence of cyclase activity in
retinal plexiform layers but these methods did not permit distinction between
nitric oxide-sensitive and insensitive cyclases. In this study, we fractionated
retinal homogenate into the cytosolic and synaptosomal fractions and investigated
the specific activity and distribution of soluble guanylate cyclase and nitric
oxide synthase. The results show that both enzymes are present in the
synaptosomal fractions derived from inner and outer plexiform layers. The
synaptosomal fraction derived from inner retina was highly enriched in cyclase
activity. Nitric oxide synthase activity was also higher in the inner than outer
retinal synaptosomal fraction. The results suggest that the nitric oxide-cyclic
GMP system is operational in both synaptic layers of retina and that it may play
a more significant role in the inner retina.
PMID- 9764530
TI - Peripheral shift reduces visual sensitivity in cat geniculate neurones.
AB - The sudden displacement of the retinal image during a saccade raises the visual
threshold of human observers to foveal stimuli. The fall in visual sensitivity
observed during this phenomenon, known as saccadic suppression, seems to occur
very early in the visual processing chain. The lateral geniculate nucleus (LGN)
is a likely locus for the multiple retinal and extraretinal interactions
occurring during saccadic eye movements, therefore we used the responses of relay
cells of adult cats to simulate a psychophysical experiment. We first measured
the responses of X and Y relay cells (27 X and 13 Y) to central spots of optimal
size and different contrasts. The spots were presented either alone or time
locked with the rapid movement of a large, high-contrast peripheral pattern,
referred to as shift. We measured the percentage of trials on which the relay
cell fired more spikes when the spot (contrast: 0.03-1.0) was present than when
it was absent. In experiments with human observers the task was to indicate, by a
keypress, which of two otherwise identical temporal intervals contained the spot.
The shift reduces the sensitivity (raises the contrast threshold) of neurones in
the cat relay cells to brief, stationary targets presented to the receptive-field
center. The suppression of visual sensitivity is significantly greater in Y cells
than in X cells (average sensitivity ratios 5.6 +/- 5.4 in Y cells, 1.59 +/- 0.9
in X cells: P < 0.001, U test). The shift also reduces the sensitivity of human
observers to the same target. This suggests that the LGN is a potential locus for
the modulation of visual responses that leads to saccadic suppression.
PMID- 9764531
TI - Localization of nitric oxide synthase, NADPH diaphorase and soluble guanylyl
cyclase in adult rabbit retina.
AB - Nitric oxide (NO) acts as a neuronal messenger which activates soluble guanylyl
cyclase (SGC) in neighboring cells and produces a wide range of physiological
effects in the central nervous system (CNS). Using immunocytochemical and
histochemical stains, we have characterized the NO/SGC system in the rabbit
retina and to a lesser extent, in monkey retina. Based on staining patterns
observed with an antibody to nitric oxide synthase (NOS) type I and a
histochemical marker for NADPH diaphorase, a metabolic intermediate required for
NOS activity, three major classes of neurons appear to generate NO in the rabbit
retina. These include two subclasses of sparsely distributed wide field amacrine
cells, rod and cone photoreceptors, and a subpopulation of ganglion cells.
Equivalent cell populations were labeled in monkey retina. An antibody to SGC
(tested only in rabbit retina), labeled large arrays of cone photoreceptors in
the outer nuclear layer, both amacrine and bipolar cells in the inner nuclear
layer (INL), as well as populations of neurons in the ganglion cell layer. These
data suggest that the ability to generate NO is restricted to relatively few
neurons in the inner retina and to photoreceptor cells in the outer retina; while
presumptive target cells, containing pools of SGC, are widespread and form
contiguous fields across the inner and outer nuclear layers (ONL) as well as the
ganglion cell layer.
PMID- 9764532
TI - Serotonin receptors modulate rod signals: a neuropharmacological comparison of
light- and dark-adapted retinas.
AB - Previous physiological studies have shown that serotonin (5-HT) reciprocally
modulates ON and OFF channels in the mammalian retina. This study was undertaken
to determine if the serotoninergic system is exclusively associated with the rod
pathway. We tested drugs specific to 5-HT3 receptor, a serotonin-gated ion
channel, in both dark- and light-adapted retina. Consistent with previous
studies, we demonstrated that 5-HT3 receptors modulate the light-evoked responses
of ganglion cells in the dark-adapted state. Moreover, we have extended these
prior studies and shown that activation of the 5-HT3 receptor is capable of
completely blocking the light-evoked response of OFF-center cells whereas
inactivation of the 5-HT3 receptor is capable of completely blocking the light
evoked responses of ON-center cells. In contrast, in light-adapted retinae,
serotonin agents failed to have any effect on retinal processing. These data
suggest that the serotoninergic system in retina is (1) specifically associated
with rod-related pathways; and (2) exerts a powerful modulatory force over
information transfer in the retina. Together these observations suggests that
serotonin plays an important physiological role in modulating retinal processing.
PMID- 9764534
TI - Electroretinographic evaluation of spectral sensitivity in yellow and silver eels
(Anguilla anguilla).
AB - Although differences in visual pigments between developmental stages of the
European eel are well known, the expected differences in spectral sensitivity
have not been demonstrated at the electrophysiological level. In fact, one past
electroretinographic study led to the conclusion that in eels there is no change
in scotopic sensitivity, with increasing sexual maturity. In the present
experiments, electroretinograms (ERGs) were recorded from in situ eyecups of
immobilized eels Anguilla anguilla (L.) caught in coastal running waters. It was
shown that the ERG b-wave is as good an indicator of spectral sensitivity as the
unmasked late receptor potential (LRP) which directly reflects the responsiveness
of photoreceptors. Complete spectral-sensitivity curves, based on b-wave
thresholds and on thresholds of LRP subsequently isolated by means of sodium
iodate, have been obtained in the same eel. Using fitted amplitude-log intensity
functions for threshold calculation, and two models for computer-assisted fitting
of spectral-sensitivity curves, significant differences in lambda max were found
between yellow and silver developmental stages of the eel, identified by ocular
index measurements.
PMID- 9764533
TI - Comparison of the distribution and somatodendritic morphology of tectotectal
neurons in the cat and monkey.
AB - The presence of a commissure connecting the two superior colliculi suggests they
do not act independently, but the function of the tectotectal connection has
never been firmly identified. To develop a better understanding of this
commissural system, the present study determined the distribution and morphology
of tectotectal neurons in the cat and macaque monkey, two animals with well
studied, but different orienting strategies. First, we compared the distribution
of tectotectal cells retrogradely labeled following WGA-HRP injections into the
contralateral superior colliculus. In monkeys, labeled tectotectal cells were
found in all layers, but were concentrated in the intermediate gray layer (75%),
particularly dorsally, and the adjacent optic layer (12%). Tectotectal cells were
distributed throughout nearly the entire rostrocaudal extent of the colliculus.
In cats, tectotectal cells were found in all the layers beneath the superficial
gray, but the intermediate gray layer contained the greatest concentration (56%).
Labeled cells were almost exclusively located in the rostral half of the cat
superior colliculus, in contrast to the monkey distribution. In the context of
the representation of visuomotor space in the colliculus, the distribution of
monkey and cat tectotectal cells suggests a correspondence with oculomotor range.
So these neurons may be involved in directing orienting movements performed
within the oculomotor range. The somatodendritic morphology of tectotectal cells
in these two species was revealed by homogeneous retrograde labeling from
injections of biocytin or biotinylated dextran amine into the contralateral
colliculus. The cell classes contributing to this pathway are fairly consistent
across the two species. A variety of neuronal morphologies were observed, so
there is no single tectotectal cell type. Instead, cell types similar to those
found in each layer, excepting the largest neurons, were present among
tectotectal cells. This suggests that a sample of each layer's output is sent to
the contralateral colliculus.
PMID- 9764535
TI - Interaction between rod and cone signals in responses of lateral geniculate
neurons in dichromatic marmosets (Callithrix jacchus).
AB - Parvocellular (P-) and magnocellular (M-) cells in the marmoset LGN can receive
prominent rod input up to relatively high illuminance levels (Kremers et al.,
1997b). In the present paper, we quantify rod and cone input strengths under
different retinal illuminance levels. The stimulus was based on the so-called
"silent substitution" method. The activities of P- and M-cells of dichromatic
animals were recorded extracellularly. We were able to adequately describe the
response amplitudes and phases by a vector summation of rod and cone signals. At
low retinal illuminance levels, the cells' responses were determined by rod and
cone inputs. With increasing illuminances the strength of the cone input
increased relative to the rod strength. But, we often found significant rod
inputs up to illuminances equivalent to 700 td in the human eye or more. Rod
input strength was more pronounced in cells with receptive fields at large
retinal eccentricities. The phase differences between rod and cone inputs suggest
that the rod signals lag about 45 ms behind the cone signals.
PMID- 9764536
TI - Nitric oxide modulates cGMP levels in neurons of the inner and outer retina in
opposite ways.
AB - In the mammalian retina, neuronal nitric oxide synthase (NOS) is mainly localized
in subpopulations of amacrine cells. One function of nitric oxide (NO) is to
stimulate soluble guanylate cyclases which in turn synthesize cGMP. We used an
antibody specific for cGMP to demonstrate cGMP-like immunoreactivity (cG-IR) in
bovine, rat, and rabbit retinae and investigated the effects on cGMP levels of
both exogenously applied NO and of endogenously released NO. We found that cGMP
levels in inner and outer retina were controlled in opposite ways. In the
presence of the NO-donors SNP, SIN-1 or SNAP, cG-IR was prominent in neurons of
the inner retina, mainly in cone bipolar cells, some amacrine and ganglion cells.
Retinae incubated in IBMX showed weak cG-IR in bipolar cells. Glutamate increased
cG-IR in the inner retina, presumably by stimulating endogenous NO release,
whereas NOS inhibitors or GABA and glycine decreased cG-IR in bipolar cells by
reducing NO release. In somata, inner segments and spherules of rod
photoreceptors the situation was reversed. cG-IR was undetectable in the presence
of NO-donors or glutamate, was moderate in IBMX-treated retinae, but increased
strongly in the presence of NOS inhibitors or GABA/glycine. We conclude that NO
is released endogenously in the retina. In the presence of NO, cGMP levels are
increased in neurons of the inner retina, but are decreased in rods.
PMID- 9764537
TI - Threshold fluctuations on temporally modulated backgrounds: a possible
physiological explanation based upon a recent computational model.
AB - When a temporally fluctuating background is rapidly modulated (e.g. 30 Hz), the
threshold variation of a superimposed flash (the probe) is approximately
sinusoidal and in phase with the stimulus. But, with low rates of sinusoidal
modulation (e.g. 1 Hz), the threshold variation is distinctly nonsinusoidal in
shape. The bases of these aspects of the data, as well as an unmodulated, dc,
threshold elevation, are poorly understood. Here 30-Hz and 1-Hz conditions are
simulated using a new model of light adaptation (Wilson, 1997). By assuming that
the OFF pathway is twice as sensitive as the ON pathway, the model correctly
captured the key aspects of both conditions. The results suggest that the 1-Hz
data are mediated by a mixture of ON and OFF pathways while the 30-Hz data are
largely mediated by the OFF pathway. The probe thresholds on the 30-Hz background
appear approximately sinusoidal and approximately in phase with the background
stimulus. A number of factors contribute to this deceptively simple observation.
PMID- 9764538
TI - Dual expression of GABA or serotonin and dopamine in Xenopus amacrine cells is
transient and may be regulated by laminar cues.
AB - Both local cell-cell interactions and lineage bias have roles in determining the
different retina cell phenotypes. In this study, subpopulations of amacrine cells
that dually express GABA or serotonin (5-HT) and dopamine (DA) are identified in
the early Xenopus tadpole (stages 42-48) retina. GABA is first detected by
immunocytochemistry in amacrine cells at stage 35/36, 5-HT at stage 39, and DA at
stage 41. As the number of these subtypes of amacrine cells increases by
differentiation, a subset of them transiently express two neurotransmitters.
GABA/DA double-labeled amacrine cells are detected first at stage 42, at which
time they constitute 52% of the DA-containing population; this percentage
decreases to only 3% by stage 48. 5-HT/DA amacrine cells are detected only at
stage 44, constituting about 20% of the DA-containing cells and 4% of the small
dim 5-HT-containing cells. Regional location does not differentially affect the
differentiation of these three types of amacrine cells (DA only, GABA/DA, and 5
HT/DA cells); each type is found more in the anterior and dorsal than the
posterior and ventral quadrants, and their overall distribution patterns are
statistically indistinguishable. However, these subtypes of amacrine cells reside
in different sublamina of the inner nuclear layer. DA-only amacrine cells are
located predominantly in the inner sublayer of the 2-3 cell thick amacrine cell
layer, closest to the inner plexiform and the ganglion cell layers. Both types of
double-labeled cells are located mostly in the outer sublayer of the amacrine
cell layer, closest to other interneurons in the inner nuclear layer. This
distinct sublaminar location of different neurotransmitter phenotypes suggests
that local laminar cues influence the coexpression of neurotransmitters in
amacrine cells.
PMID- 9764539
TI - Responses of regular spiking and fast spiking cells in turtle visual cortex to
light flashes.
AB - Sharp electrodes were used to record light-evoked postsynaptic potentials (PSPs)
from neurons in turtle visual cortex in an in vitro preparation of the
geniculocortical pathway. Neurons were placed into four groups based on the
firing patterns produced by intracellular current injections: regular spiking
(RS), fast spiking (FS), intrinsic bursting (IB), and chattering (CH) cells. RS
cells have been shown to be pyramidal cells while FS cells are typically
interneurons. Light stimuli were diffuse, 1-s flashes of 640-nm light with
intensities (I) varying from 0 to 10(4) photons microm(-2) s(-1). The response
(R) in each case was the maximal amplitude of the light-evoked depolarizing PSP.
Cells of all four types showed sigmoidal intensity-response (IR) functions with a
linear rising phase for stimuli above the intensity threshold followed by
saturation at high light intensities. Responses at high intensities were variable
and some cells showed indications of supersaturation. Light-evoked PSPs had
longer latencies and times-to-peak response in RS cells than they did in FS
cells. RS cells fired action potentials as much as 200 ms later than did FS
cells. Since responses recorded in RS cells at light intensities just above
threshold are unlikely to involve contributions from other pyramidal cells, these
data indicate that the geniculocortical or feedforward pathway to pyramidal cells
has a high gain. The fact that FS cells fire well before RS cells suggests that
feedforward inhibition plays a role in controlling the gain of the
geniculocortical pathway.
PMID- 9764540
TI - Defect repair after somite removal in avian embryos is not true regeneration.
AB - The question of regeneration after experimental somite extirpation has been
controversial in the literature. While all workers agree that repair of the
defects occurs, results concerning the extent and mechanism of this process, as
well as the origin of the cells filling the defect, show great discrepancies. Our
approach towards a re-examination of this question involved microsurgical removal
of individual somites in 2-day-chick embryos in combination with grafting of
quail somites and lateral plate. We show that the defect in the paraxial mesoderm
is filled within a day after extirpation and that the reconstituting cells are
derived only from the cranial and caudal somites, but not from the contralateral
somites or from the lateral plate. There are no indications of an increase of
proliferation in the neighbouring somites. In order to examine the
differentiation capacities of the cells that fill the defect, we used
immunohistochemistry and in situ-hybridization. We show that the cells in the
defect are mesenchymal in morphology and express Pax-1 and Twist. There are a few
desmin-positive cells in the defect that can be shown to derive from adjacent
somites. An epithelial dermomyotome and myotome are absent at the operation site.
Neural crest cells do not participate in the reconstitution of the defect. We
conclude that cells in the defect either already have or adopt a ventral somitic
(sclerotomal) identity, whereas derivatives with dorsal identity are absent from
the defect except for a few individual cells.
PMID- 9764541
TI - Vascularization of embryonic adrenal gland grafted onto chorioallantoic membrane.
AB - Vascularization and endothelial phenotype expression were analysed in embryonic
adrenal tissue grafted onto chorioallantoic membrane (CAM), by means of routine
light microscopy and immunocytochemical staining, and of electron microscopy.
Adrenal gland tissue from chick or quail embryos (donors) was grafted onto CAMs
of chick or quail embryos (host). Vessels of chick origin were discriminated from
those of quail origin by monoclonal antibodies, anti-MB1, specific for quail
endothelial and haemopoietic cells, and QCPN, which labels quail cell nuclei.
Vessels of adrenal type were distinguished from those of CAM-type by their
ultrastructural endothelial phenotype - porous in the former and continuous in
the latter. The observations carried out 6 days after implantation indicate that
the adrenal gland develops and differentiates according to a virtually normal
histological pattern. As regards the adrenal and CAM vascularization, the
grafting procedure elicits angiogenic events consisting in the formation of
peripheral anastomoses between the graft and the CAM original microvasculature
and in new-growth of vessels from the CAM into the grafted tissue and vice versa.
As to the endothelial phenotype, the ultrastructural results demonstrate that
besides its own native vasculature, the adrenal tissue contains vessels with
continuous endothelium and the CAM mesenchyme is supplied by adrenal-type,
fenestrated vessels.
PMID- 9764542
TI - Subcellular compartmentation of glutathione and glutathione precursors. A high
resolution immunogold analysis of the outer retina of guinea pig.
AB - Selective antibodies were used to assess the cellular and subcellular
localization of glutathione, and the glutathione precursors gamma
glutamylcysteine, glutamate, and cysteine, in neuronal (photoreceptors) and non
neuronal (pigment epithelial cells and Muller cells) cell types in the outer
retina of the guinea pig. In each cell type the highest level of glutathione
immunoreactivity occurred in the mitochondria. The labeling density in the
cytoplasmic matrix was higher (and the mitochondrial-cytoplasmic gold particle
ratio lower) in pigment epithelial cells than in Muller cells and photoreceptors.
The latter two cell types showed a mitochondrial-cytoplasmic gold particle ratio
of 15.5 and 21.7, respectively. In contrast to glutathione, gamma
glutamylcysteine seemed to be enriched in the cytoplasmic matrix relative to the
mitochondria. The immunogold labeling for this dipeptide was stronger in the
pigment epithelial cells than in Muller cells and photoreceptors. Glutamate
immunoreactivity was high in photoreceptors, intermediate in pigment epithelial
cells, and low in Muller cells, while the cysteine immunogold signal was low in
each cell type and cell compartment. The present results suggest that glutathione
is concentrated in mitochondria but to different degrees in different cells. The
low mitochondrial content of gamma-glutamylcysteine (the direct precursor of
glutathione) is consistent with biochemical data indicating that glutathione is
synthesized extramitochondrially and transported into the mitochondrial matrix.
Judged from the immunocytochemical data, cysteine may be a rate-limiting factor
in glutathione synthesis in each cell type while glutamate can be rate limiting
only in Muller cells.
PMID- 9764543
TI - Early development of the zebrafish (Danio rerio) pharyngeal dentition (Teleostei,
Cyprinidae).
AB - In order to build a reference system to assess ongoing in vitro and in situ
hybridisation experiments on epithelial-mesenchymal interactions governing
odontogenesis in the zebrafish, we describe here the generation of the pharyngeal
dentition, and the histological development of teeth up to fourteen days post
fertilization, using serial semithin sections, handmade and computer-assisted
reconstructions and transmission electron microscopy. The tooth pattern in larval
zebrafish is generated in a predictable, and bilaterally symmetrical manner from
shortly before hatching onwards. Characteristics related to tooth development and
structure differ considerably from those seen in juvenile specimens and those
described for other bony fishes. Particular features related to the cyprinid
condition include the complex epithelial connectivity and the mode of attachment
of the teeth.
PMID- 9764544
TI - Immunoreactivity of the ets-1 transcription factor correlates with areas of
epithelial-mesenchymal transition in the developing avian heart.
AB - Cardiac morphogenesis involves substantial remodeling processes that include cell
transdifferentiation and migration. The c-ets-1 protooncogene codes for a
transcription factor that can transactivate a number of genes involved in
developmental processes such as degradation of extracellular matrices and cell
migration. We have immunolocated the ets-1 protein in the heart of quail and
chick embryos between the Hamburger and Hamilton stages HH16 and HH37. In HH16-17
embryos, the ets-1 transcription factor was only detected in some endocardial
cells and in most mesothelial and mesenchymal cells of the proepicardium. Ets-1
immunoreactivity increased markedly in the developing endocardial cushions,
myocardium, epicardium and early subepicardial mesenchyme of HH18-19 embryos. By
HH20-24 the immunoreactivity was found throughout the heart, with a stronger
intensity in the areas of epithelial-mesenchymal transition of the endocardium
and epicardium. In embryos between HH26 and HH33, ets-1 immunoreactivity
increased in the cushion mesenchyme, atrioventricular endocardium, ventricular
epicardium and subepicardial mesenchyme cells, but not in other areas of the
heart. The immunoreactivity declined in the innermost part of the endocardial
cushions. The subepicardial mesenchyme was particularly immunoreactive in these
stages, coinciding with the development of the subepicardial vascular network. In
fact, ets-1 colocalized with the quail vascular marker QH1 in the subepicardial
mesenchymal cells. Ets-1-negative cells were abundant in the subepicardium and
valvuloseptal tissue of the HH37 embryos. The results suggest that ets-1,
probably through transactivation of genes such as urokinase-type plasminogen
activator and matrix metalloproteinases, might play a crucial role in the
differentiation of the cushion and subepicardial mesenchyme, the formation of the
intratrabecular sinusoids and the early development of the cardiac vessels.
PMID- 9764545
TI - Development of the atrioventricular valve tension apparatus in the human heart.
AB - Using various microscopical techniques we studied the development of the
atrioventricular valves in human hearts between 5 and 19 weeks of development.
Within the atrioventricular cushions two different layers could be recognized
that remained present in all ages studied. The atrial layer, being present at the
side of the atrioventricular orifice, was positive for laminin while the
ventricular layer, that was connected to the myocardium, was positive for
fibronectin and collagen III. Fate-mapping of these two layers, morphometrics,
and scanning electron microscopy, supplemented with in vivo labeling of cushion
tissue in chicken hearts have lead to new insights in the process of valve
development. The cushions became freely movable prevalvular leaflets by
delamination of ventricular myocardium underneath the cushion tissue. This
myocardium gradually retracted towards annulus and papillary muscles and finally
disappeared, resulting in fibrous, non-myocardial valves. The atrial layer of the
cushions remained present as a jelly-like surface on the valve leaflets while the
ventricular layer of the cushions became the compact fibrous tissue of the
leaflets and the chords. Chordal development was first visible at 10 weeks of
development when gaps were formed in the ventricular layer of the cushions on top
of the papillary muscles. These gaps enlarged into the interchordal spaces while
the cushion tissue in between the gaps lengthened to form the chords. We conclude
that the leaflets as well as the chords of the atrioventricular valves are
derived from atrioventricular cushion tissue. Myocardium is only important for
loosening of the leaflets while keeping connection with the developing papillary
muscles. Errors in delamination or retraction of myocardium or remodeling of
cushion tissue into chords form the basis for various congenital valve anomalies.
PMID- 9764546
TI - Lectin binding patterns in the vomeronasal organ and accessory olfactory bulb of
the rat.
AB - A number of previous studies have indicated that lectin histochemistry is an
obvious choice for characterizing the vomeronasal system. However, apparently
inconsistent results have been obtained: notably, the affinity with which various
lectins bind to the accessory olfactory bulb varies among taxa, even considering
closely related species. In the present study, the binding patterns of seven
lectins in the rat accessory olfactory bulb, vomeronasal nerves and vomeronasal
duct were investigated. The Bandeiraea simplicifolia lectin bound exclusively to
the vomeronasal nerve and glomerular layers of the accessory olfactory bulb,
while the Ulex europeus and Lycopersicon esculentum lectins bound to these
regions and additionally to the nerve and glomerular layers of the main olfactory
bulb. Soybean agglutinin showed a similar pattern to that obtained with the Ulex
europeus and Lycopersicon esculentum lectins, though it also faintly labelled
other parts of the structures examined. The Vicia villosa and Erythrina
cristagalli lectins were not specific for the vomeronasal system, since they
labelled grey and white matters in structures including the lateral olfactory
tract and the anterior olfactory nuclei. The Dolichos biflorus lectin did not
bind to vomeronasal tissues. The observed patterns of binding in the accessory
olfactory bulb were consistent with those observed in the vomeronasal nerves, but
unlike those observed in the epithelium of the vomeronasal duct. This latter
result probably reflects binding of lectins to sugar residues contained in
secreted mucus rather than those in epithelial nerve endings.
PMID- 9764547
TI - Risk assessment and risk-based therapy in febrile neutropenic patients.
PMID- 9764548
TI - Bacterial DNA as an evolutionary conserved ligand signalling danger of infection
to immune cells.
AB - During infection, the innate limb of the immune system senses danger (pathogens)
via constitutively expressed pattern-recognition receptors, and responds with
activation and secretion of pro-inflammatory cytokines. Cell-wall components of
gram-positive and gram-negative bacteria, such as peptidoglycan, endotoxin or
lipoteichoic acid, activate via CD14, a prototypic pattern-recognition receptor
for carbohydrates. This review article focuses on an alternative recognition
system of the innate immune system for the recognition of bacterial DNA.
Bacterial DNA differs from eukaryotic DNA in its frequency of the dinucleotides
CG and its lack of methylation. These structural differences appear to be sensed
by cells of the innate immune system such as antigen-presenting cells. As a
consequence bacterial DNA serves as an alternate ligand to signal danger of
infection. Bacterial DNA and (synthetic) oligonucleotides (ODN) derived thereof
are as efficient as endotoxin in activating macrophages and dendritic cells and
in triggering release of pro-inflammatory cytokines. In mice sensitized with D
galactosamine (D-GalN), high doses of bacterial DNA from either gram-positive or
gram-negative pathogens induce a lethal cytokine syndrome (lethal shock).
Therefore, bacterial DNA may represent a hitherto unrecognized pathophysiological
entity in host-parasite interactions. Moreover, recent evidence suggests that
bacterial DNA or immunostimulating ODN triggers the immunostimulation of antigen
presenting cells, and can be utilized as adjuvant to enhance immune responses of
the adaptive immune system towards poorly immunogenic antigens. In fact, foreign
DNA might be useful as immunotherapeutically active adjuvant to direct adaptive
immune responses towards Thl-dominated immune reactions. If these findings are
operative in humans, immunostimulating ODN might be used to influence Th2
dominated diseases such as allergy.
PMID- 9764549
TI - Multicenter, randomized, double-blind comparison of erythromycin estolate versus
amoxicillin for the treatment of acute otitis media in children. AOM Study Group.
AB - Erythromycin is frequently prescribed in Germany for acute otitis media, but well
designed clinical trials under present epidemiological conditions are lacking.
Therefore, a double-blind, randomized, multicenter trial was performed to compare
the clinical efficacy and safety of erythromycin estolate versus amoxicillin in
children with acute otitis media and to identify the risk factors associated with
clinical failure. Investigators from 19 centers throughout Germany recruited 302
children with clinical, otoscopic, and tympanometric evidence of acute otitis
media. In a double-blind fashion, patients were allocated randomly to a 10-day
course of erythromycin estolate at 40 mg/kg/day in two divided doses or
amoxicillin at 50 mg/kg/day in two divided doses. Clinical examinations,
otoscopy, and tympanometry were performed at baseline, day 3-5, day 9-11, and at
5 weeks. Clinical outcome was assessed on day 9-11. Two-hundred eighty children
were evaluable for efficacy (erythromycin group, 141; amoxicillin group, 139).
Both groups were comparable with respect to demographic data and severity of
disease at entry. Treatment was successful in 94% of the erythromycin-treated
patients and in 96% of the amoxicillin-treated patients. Clinical outcome was
statistically equivalent between groups within a range of 7 percentage points.
Clinical recurrence was seen in eight erythromycin-treated children (5.7%) and in
seven amoxicillin-treated children (5.0%) (P=0.81). Patients with bilateral
disease at entry were at higher risk of unfavourable outcome, whereas age and
presence/absence of otorrhea at entry were not associated with outcome. Treatment
related adverse events were recorded in eight (5.3%) of 151 erythromycin-treated
patients and in 11 (7.3%) of 151 amoxicillin-treated patients. In this study in
an outpatient setting in Germany, erythromycin estolate was as safe and effective
as amoxicillin in the treatment of acute otitis media. Both drugs can be
administered in a convenient twice-daily dosage schedule.
PMID- 9764550
TI - Evaluation of six commercial systems for identification of medically important
yeasts.
AB - Six commercially available systems for the identification of yeasts were
evaluated using 133 clinical isolates and four reference strains that had been
previously identified by conventional methods and 19 recent clinical isolates
that had been identified by the ID32C system (bioMerieux, France). The total
identification rates (TIR) established for the total number of strains tested and
the database identification rates (DBIR) established for the strains included in
the respective manufacturer databases were both determined. After incubation for
4 h, the TIR and DBIR were 78% and 84%, respectively, for the RapID Yeast Plus
system (Innovative Diagnostic Systems, USA). After incubation for 24 h, the TIR
and DBIR were 32% and 32%, respectively, for the ID32C, 65% and 67% for the
Auxacolor system (Sanofi Diagnostics Pasteur, France), 62% and 65% for the
Fungichrom I system (International Microbio, France), 52% and 65% for the
Fungifast I twin system (International Microbio), and 62% and 68% for the API
Candida system (bioMerieux). The maximum TIR and DBIR (+/- 1%) obtained after
incubation for 48 h were 86% and 88% for the Auxacolor, 85% and 89% for the
Fungichrom I, 78% and 98% for the Fungifast I twin, and 82% and 91% for the API
Candida. For the ID32C, the maximum TIR and DBIR were 98% and 98%, respectively,
but these values were obtained only after 72 h of incubation. In addition, the
six systems varied in their ease of use and readings. In conclusion, based on
results obtained with 156 strains, the Auxacolor and Fungichrom systems seem the
most appropriate for use in a clinical microbiology laboratory, due to their ease
of use and reading, their rapidity, their cost per test, and their relatively
high TIR results, which indicated acceptable performance with strains frequently
isolated in our hospital. For a reference identification, the ID32C remains the
sole system usable.
PMID- 9764551
TI - Use of a selective medium and a membrane filter method for isolation of
Campylobacter species from Spanish paediatric patients.
AB - A study was conducted to assess the value of a combination of two culture methods
for isolation of Campylobacter spp. from Spanish children. Seven hundred twenty
nine diarrhoeal stool specimens from 599 patients were examined for Campylobacter
spp. by culturing them on charcoal cefoperazone deoxycholate agar and on blood
agar with a membrane filter. One hundred sixteen Campylobacter strains were
isolated from a total of 108 specimens; 75 (64.6%) were Campylobacter jejuni, 32
(27.5%) were Campylobacter coli, 8 (6.8%) were non-typeable, and one (0.9%) was
Campylobacter upsaliensis. Campylobacters were isolated from 99 positive samples
using charcoal cefoperazone deoxycholate agar alone. The filtration technique
alone yielded only 86 positive samples. Seven specimens yielded different
Campylobacter spp. with different media. The only catalase-negative strain was
recovered using the filter method. The combination of the selective medium with
the filter method increased the isolation rate of Campylobacter strains by 14.1%.
Isolation rates of campylobacters using the filter method were similar to those
reported in European studies, in which a similar frequency of Campylobacter
upsaliensis was observed. The addition of a filter method for routine laboratory
isolation of campylobacters should be considered in selected age groups (in
children < 10 years of age) or in areas where catalase-negative or weakly
positive Campylobacter strains may be of epidemiological significance.
PMID- 9764552
TI - Use of microscopic morphology in smears prepared from radiometric cultures for
presumptive identification of Mycobacterium tuberculosis complex, Mycobacterium
avium complex, Mycobacterium kansasii, and Mycobacterium xenopi.
AB - The aim of this study was to assess the feasibility of a method for presumptive
identification of mycobacteria, based on the morphology in smears prepared from
radiometric Bactec-positive cultures (Becton Dickinson, USA) and to select the
appropriate DNA probe (AccuProbe; Gen Probe, USA). The smear morphology of acid
fast bacilli was evaluated in 468 positive cultures from clinical samples: 313
Mycobacterium tuberculosis complex, 67 Mycobacterium avium complex, 32
Mycobacterium kansasii, 49 Mycobacterium xenopi, and seven Mycobacterium
gordonae. The sensitivity and specificity for various morphological patterns were
as follows: cord formation for Mycobacterium tuberculosis complex 90% and 100%,
respectively; striped bacilli for Mycobacterium kansasii, 66% and 99%; sea urchin
for Mycobacterium xenopi, 96% and 99%; short bacilli for Mycobacterium avium
complex, 61% and 99%; fine-striped bacilli associated with Mycobacterium avium
complex from blood samples, 33% and 98%. This criterion was applied in the
selection of a suitable DNA probe for the identification of 178 cultures. The
correct probe was selected in 98%, 97%, and 72% of cultures, respectively, for
Mycobacterium tuberculosis complex, Mycobacterium avium complex, and
Mycobacterium kansasii. The observation of acid-fast bacilli morphology in
radiometric cultures is a rapid and cost-efficient method for presumptive
identification of common clinical isolates of mycobacteria.
PMID- 9764553
TI - Ceftriaxone in the outpatient treatment of cancer patients with fever and
neutropenia.
AB - A study was performed in low-risk cancer patients with chemotherapy-induced
febrile neutropenia to determine the safety and efficacy of ceftriaxone given in
an outpatient setting. A total of 126 episodes of febrile neutropenia in 120
clinically stable outpatients were treated with intravenous ceftriaxone alone
(n=100) or in combination with other antibiotics (n=26). The mean neutrophil
count was 460/mm3; severe neutropenia (< 100/mm3) was observed in 18 episodes.
The initial treatment with ceftriaxone (alone or in combination) was successful
in 99 episodes (78%). Ninety-five episodes (76%) were successfully treated in an
outpatient setting only; admission to hospital was necessary in 31 episodes
(24%), but no infection-related death was observed. Ceftriaxone seems to be safe
and effective for outpatient therapy of patients with low-risk febrile
neutropenia.
PMID- 9764554
TI - Stomatococcus mucilaginosus septicemia in a patient with acute lymphoblastic
leukaemia.
AB - A 16-year-old patient with acute lymphoblastic leukaemia which had relapsed for
the third time developed clinical signs and symptoms of septicemia during a
period of neutropenia. The patient had signs of oral mucositis, and Stomatococcus
mucilaginosus was isolated from blood cultures. The patient responded well to
antibiotic therapy. The biochemical characteristics and antimicrobial
susceptibility patterns of 68 other pharyngeal isolates of Stomatococcus
mucilaginosus from immunocompromised patients are presented.
PMID- 9764555
TI - Significance of ahpC promoter mutations for the prediction of isoniazid
resistance in Mycobacterium tuberculosis.
AB - To determine the value of ahpC promoter mutations for the rapid prediction of
isoniazid resistance, this genomic region was characterized in 50 isoniazid
resistant and 12 isoniazid-sensitive Mycobacterium tuberculosis isolates. Of the
resistant isolates, 12 had ahpC promoter mutations, but only one possessed both
an ahpC promoter mutation and a katG codon 315 substitution, although the latter
was found in the majority (54%) of the isoniazid-resistant isolates investigated.
This investigation presents empirical evidence that the central portion of the
ahpC promoter is the most valuable genetic locus to complement katG codon 315
characterizations in order to increase the sensitivity of molecular tests for the
prediction of isoniazid resistance.
PMID- 9764556
TI - Five cases of Kingella kingae skeletal infection in a French hospital.
AB - Five cases of Kingella kingae skeletal infections were diagnosed in children
admitted to La Timone Hospital between 1992 and 1997. Patients were between 6 and
31 months old and presented with septic spondylodiskitis, calcaneus
osteomyelitis, and hip-joint arthritis. All displayed either an upper respiratory
tract infection or eczema during the month prior to their admission. Laboratory
findings included an elevated leukocyte count and an elevated erythrocyte
sedimentation rate. Standard radiography was unrevealing, but 99mTc bone scans
and magnetic resonance imaging showed significant abnormalities. Isolation of
Kingella kingae was achieved in all cases by culture of fluid aspirates using the
Bactec blood culture system. This bacterium was sensitive to the most common
antibiotics tested, and the outcome was favourable in all cases.
PMID- 9764557
TI - Isolation of a novel mycobacterium from an adolescent with cervical
lymphadenitis.
AB - A slow-growing mycobacterium was isolated from a cervical lymph node of an
adolescent male. This isolate produced small, smooth, scotochromogenic colonies
after 6 weeks of incubation at 25 degrees C and 30 degrees C (but not at 37
degrees C or 43 degrees C). The results of 16S-rRNA gene sequencing and high
performance liquid chromatography suggest that this isolate belongs to a hitherto
unrecognised pathogenic species.
PMID- 9764558
TI - Prevalence of Helicobacter pylori resistance to several antimicrobial agents in a
region of Germany.
AB - To evaluate the prevalence of resistance among Helicobacter pylori in Germany,
the minimum inhibitory concentrations of amoxicillin, tetracycline,
clarithromycin, and metronidazole were determined by means of the E test, for 271
Helicobacter pylori isolates cultured from biopsies taken during routine
endoscopies in 1996 and 1997. The prevalence of metronidazole resistance was
32.1%, with resistance found more frequently in women (38.5%) than in men
(24.4%). Clarithromycin resistance was rare (3.3%). Eight of nine strains
resistant to clarithromycin were also resistant to metronidazole. Resistance to
either metronidazole or clarithromycin was significantly (P=0.022) higher in
patients with duodenal ulcer. No strain was found to be resistant to amoxicillin
or tetracycline.
PMID- 9764559
TI - Comparison of three monoclonal antibody pools for the detection of respiratory
viral antigen in respiratory secretions.
AB - The aim of this study was to compare the sensitivities of commercial monoclonal
antibody pools to be used as an initial rapid screen for detection of viral
antigens in respiratory secretions. The availability of commercial monoclonal
antibodies has dramatically improved the detection of viruses by
immunofluorescence techniques in exfoliated cells obtained from respiratory
secretions. Several companies have recently introduced monoclonal antibody pools
to detect the presence of respiratory viruses in a single preparation. Ninety
four stored slide preparations that had previously been examined by individual
monoclonal antibodies were tested using three commercial monoclonal antibody
pools produced by Sanofi (UK), Dako (UK), and Quadratech (UK). These monoclonal
antibody pools had a sensitivity of 79.6%, 90.9%, and 100%, respectively, when
compared with the original results. The overall intensity of immunofluorescence
was also examined.
PMID- 9764560
TI - Evaluation of restriction fragment length polymorphism analysis of the UL10-UL13
genomic region for rapid identification of human cytomegalovirus strains.
AB - A sensitive semi-nested polymerase chain reaction (PCR) was established which
allows rapid identification of human cytomegalovirus strains directly on clinical
specimens, thereby permitting virus isolation and propagation on cell cultures to
be avoided. The assay is based on restriction analysis of PCR products derived
from the polymorphic UL10-UL13 region of the human cytomegalovirus genome. The
method was evaluated using clinical samples from 23 subjects comprising 16 breast
feeding mothers and seven bone marrow transplantation recipients. For eight
mothers, postnatal virus transmission to their offspring via breast milk was
studied. Interestingly, for one mother-infant pair, a double infection with two
distinct human cytomegalovirus strains could be demonstrated. Stepwise digestion
with different restriction enzymes raised the possibility of detecting different
strains almost twofold compared to analysis with only one enzyme. This assay is a
practical tool for monitoring human cytomegalovirus transmission in various
clinical settings.
PMID- 9764561
TI - Submandibular gland infection by Mycobacterium avium-intracellulare in an AIDS
patient.
PMID- 9764562
TI - Candida and bacterial mandibular osteomyelitis in an AIDS patient.
PMID- 9764563
TI - Evaluation of an indirect immunofluorescence assay and two cell lines in the
detection of influenza B virus in nasopharyngeal samples.
PMID- 9764564
TI - Porphyria cutanea tarda and hepatitis G and C virus infection.
PMID- 9764565
TI - Comparison of the effectiveness of 2,3-dimercaptopropanol (BAL) and meso-2,3
dimercaptosuccinic acid (DMSA) as protective agents against mercuric chloride
induced nephrotoxicity in rats.
AB - The effectiveness of 2,3-dimercaptopropanol (BAL) and meso-2,3-dimercaptosuccinic
acid (DMSA) on HgCl2-induced nephrotoxicity was studied in the rat. Seven groups
of adult male rats were given a single sc toxic dose of HgCl2 (0.68 mg/kg)
followed by 0.9% saline (positive control group), BAL (15, 30, and 60 mg/kg) or
DMSA (50, 100, and 200 mg/kg) administered ip at 0, 24, 48, and 72 h thereafter.
Although the renal function of HgCl2-exposed rats was slightly improved after BAL
administration, Hg concentrations in the kidney were only reduced at 60 mg/kg. In
addition, the protective effect of BAL was not dose-related. In contrast to BAL,
DMSA was effective in increasing the urinary excretion of Hg and in reducing the
renal Hg content. These results show that DMSA would be more effective than BAL
in preventing or in protecting against inorganic Hg-induced nephrotoxicity.
PMID- 9764566
TI - Structural and trace element changes in scalp hair of radiographers.
AB - Scalp hair samples were collected from medical radiographers and nonradiographers
of matching age groups. Structural morphology of hair was studied by scanning
electron microscopy, and the trace element profiles in hair were measured using
neutron activation analysis. The structural damage to the hair follicles of the
radiographers was quite obvious, and this may be a good qualitative indicator of
radiation damage at low doses. The concentrations of aluminum (Al), potassium
(K), and vanadium (V) in hair of the radiographers were significantly higher,
whereas those of antimony (Sb) and magnesium (Mg) were significantly lower than
those of nonradiographers. Some of our findings were quite consistent with those
of others in determining the changes in trace element concentrations in
irradiated tissue.
PMID- 9764567
TI - Pattern of cardiac fibrosis in rabbits periodically fed a magnesium-restricted
diet and administered rare earth chloride through drinking water.
AB - It has been postulated that causation of the tropical cardiomyopathy
endomyocardial fibrosis (EMF) is linked to magnesium (Mg) deficiency and cardiac
toxicity of the rare earth element cerium (Ce). The aim of the present study was
to define the myocardial lesions in rabbits that were fed on Mg-restricted diet
(70-80 ppm) periodically and were provided drinking water contaminated with rare
earth chloride (1 g/L). Forty New Zealand white rabbits were divided into four
groups following a 2 x 2 factorial design. Two groups were periodically fed on Mg
restricted diet with one of them receiving water contaminated with rare earth
chloride. The other two groups were continuously fed on Mg-sufficient diet (350
400 ppm) with one of them receiving water contaminated with rare earth chloride.
All animals were sacrificed at the end of 6 mo. Cardiac tissues were subjected to
histology, elemental analysis (calcium [Ca], Mg, and Ce) and estimation of
collagen content and collagen phenotypes. Histological lesions were compared with
those of EMF in humans and those of acute Mg deficiency in animals. The results
suggest that in rabbits, recurrent episodes of Mg deficiency lead to myocardial
fibrosis similar to the pattern observed in human EMF.
PMID- 9764568
TI - Influence of ascorbic acid, sodium citrate, and sodium bicarbonate on the uptake
of 59Fe-transferrin, 54Mn-transferrin, and 65Zn-transferrin from lactating mouse
mammary gland cells.
AB - The effects of ascorbic acid, sodium citrate, and sodium bicarbonate on 59Fe
transferrin, 54Mn-transferrin, and 65Zn-transferrin uptake by the receptors
disposed of plasma membrane isolated from lactating mouse mammary gland cells
have been investigated. The effect of 10(-2) mol/L ascorbic acid alone and in
combination with NaHCO3 on the 59Fe-transferrin uptake is significant and
positive. 54Mn-transferrin and 65Zn-transferrin binding to the cell receptors are
influenced optimally by 0.5 mol/L sodium bicarbonate. Sodium citrate alone or in
combination with other substances always has a negative effect on binding of
these three metals. It is suggested that a precise mechanism may exist with large
possibilities to rearrange metal uptake and its transport from blood to milk.
PMID- 9764569
TI - Significance of magnetic resonance image and blood manganese measurement for the
assessment of brain manganese during total parenteral nutrition in rats.
AB - In this study, we report on the influence of trace elements (TE) on signal
intensities of nuclear magnetic resonance images (MRI), both in vivo and in
vitro. Optimal parameters for the assessment of Mn concentration in the brain of
rats on total parenteral nutrition were established. For the in vitro study, Mn
and trace element solutions, one containing Zn, Cu, Fe, and I (TE-4) and another
containing the above elements plus Mn (TE-5), were diluted with physiological
saline or with rat brain homogenate and used to measure signal intensities in
MRI. Concentration-dependent signal hyperintensity was observed in both cases in
the Mn and the TE-5 solutions, but no effect was observed with the TE-4 solution.
The signal increase was greater for brain tissue homogenates. In the in vivo
study, the experimental animals were maintained under total parenteral nutrition
(TPN) with a standard clinical dose of TE-5 and/or with 10-fold the clinical dose
of TE-4 and TE-5 for 1 wk. Only rats that were receiving the increased TE-5 dose
showed signal hyperintensity on MRI. Positive correlations were observed among
the signal hyperintensity, the blood Mn concentrations, and that of the rat
brain. Our results suggest that Mn in TE preparations may be the cause of signal
hyperintensity on MRI in a concentration-dependent fashion, and that MRI and
measurement of blood Mn may be used to estimate Mn accumulation in brain tissue.
PMID- 9764570
TI - Effects of selenium supplementation on virus-induced inflammatory heart disease.
AB - The effects of 10 wk of selenium (Se) supplementation (5 ppm) in drinking water
on immune responses and resistance to a myocarditic Coxsackie virus B3 (CB3)
infection were studied in female Balb/c mice. Se supplementation reduced CB3
induced mortality: at day 14 postinoculation, survival was 58% in the Se-treated
group as compared to 25% in the untreated group. Whole-blood glutathione
peroxidase (GSH-Px) activity was elevated by 68% (p < 0.001) and Se content in
the liver by 24% (p < 0.001). Red (RBC) and white blood cell (WBC) counts, as
well as the number of cells in the spleen and thymus, were unaffected. The
cellular counts of T-lymphocytes (CD4+, CD8+) and natural killer (NK+) cells in
the blood were not affected. However, the CD4+/CD8+ ratio (5.2) tended to
increase after Se supplementation (5.9). The spleen lymphoproliferative response
to T- and B-cell mitogens were increased by 9 and 43%, respectively (ns), in the
Se-supplemented group. The total NK cell activity in blood and spleen showed
minor increases, but when the activity in the blood was expressed per cell, the
increase amounted to 35% (ns) with Se supplementation. The inflammatory and
necrotic lesions in the ventricular myocardium at 7 and 14 d postinoculation were
not significantly reduced by Se treatment, probably owing to the increased
survival with Se even of mice with the most pronounced heart damage; comparable
untreated mice were estimated to have died at day 14. Results indicate that
modest doses of Se can improve immune function, which may increase the general
resistance to this viral infection.
PMID- 9764571
TI - Serum and urine ionic fluoride: normal range in a nonexposed population.
AB - The present study was undertaken to evaluate the fluoride status in the general
healthy population of Barcelona. Serum and urine fluoride ionic concentration was
determined in a random sample of 250 subjects (age range 15-90 yr) by the Orion
fluoride electrode system to determine the normal range of fluoride in this
population. The results obtained show that in the general population of
Barcelona, fluoride ionic serum concentration ranges between 1 and 47 microg/L (x
= 17.5 +/- 9.7 microg/L) and fluoride ionic urine concentration ranges between
156 and 1990 microg/24 h (x = 671 +/- 373 microg/24 h). The mean serum fluoride
concentration of the younger population was shown to be significantly greater (p
< 0.05) than that of the older group. No sex-related difference was found.
PMID- 9764572
TI - Alterations in collagen metabolism and increased fibroproliferation in the heart
in cerium-treated rats: implications for the pathogenesis of endomyocardial
fibrosis.
AB - Cerium (Ce), a rare earth element, has been postulated to play a role in the
pathogenesis of tropical endomyocardial fibrosis (EMF). Investigations carried
out recently in pursuance of the postulation furnished histological evidence of
EMF and increased cardiac collagen content in rats on prolonged administration of
Ce. The present study was undertaken to understand the molecular basis of
myocardial injury and fibrosis produced by the element. This article presents
evidence of increased lipid peroxidation and elevated rates of fibroblast
proliferation and collagen deposition in the heart in Ce-treated rats. It is
suggested that the element may trigger a wound-healing response in the cardiac
tissue leading to cardiac fibrosis.
PMID- 9764573
TI - Role of nitric oxide in pancreatic tumour growth: in vivo and in vitro studies.
AB - Nitric oxide (NO), an endogenous free radical, has been implicated in a wide
range of biological functions. NO is generated enzymatically from the terminal
guanidinonitrogen of L-arginine by nitric oxide synthase (NOS). Despite intensive
investigations, the role of NO--either as the primary product of the L
arginine/NOS pathway or provided from the NO donor sodium nitroprusside (SNP)--in
carcinogenesis and tumour cell growth remains unclear and controversial. The
objective of this study was to examine the growth effects of NO on a ductal
pancreatic adenocarcinoma in the rat and on a human pancreatic tumour cell line
(HA-hpc2). In vivo, both SNP and endogenous induction of NO by endotoxins
[lipopolysaccharide (LPS)] plus L-arginine significantly reduced the tumour
growth. To investigate the mechanisms of NO anti-tumour growth action, the
effects of either the SNP or L-arginine/NOS pathway were analysed on the HA-hpc2
cell line. Nitrite/nitrate production, NOS activity and iNOS expression [assessed
by reverse transcription-polymerase chain reaction (RT-PCR)] were tested and
related to growth (assessed by [3H]thymidine incorporation assay) and apoptosis
(assessed by internucleosomal DNA cleavage). SNP exerted a dual effect on tumour
cells: stimulation of the proliferation up to 1 mM and inhibition at higher
concentrations. These effects were related to NO production. Both proliferative
and cytostatic responses were inhibited by NO scavenger 2-phenyl-4,4,5,5
tetramethyl-hemidazoline-1-oxyl3-oxide (carboxy-PTIO). The marked apoptotic DNA
fragmentation induced by SNP was also abolished by PTIO association. Unlike
macrophages, the human pancreatic tumour cells did not seem to express
intrinsically the L-arginine/NOS pathway. Macrophages were activated by HA-hpc2
cells as well as by LPS plus cytokines [interleukin (IL)-1beta plus tumour
necrosis factor (TNF)-alpha and interferon (IFN)-gamma]. In HA-hpc2/macrophage co
cultures, NOS activity and inducible NOS (iNOS) transcription were stimulated,
whereas an antiproliferative response was observed. These effects were related to
both macrophage amount and NO production. Addition of LPS plus cytokines to co
cultures doubled iNOS activity, nitrite/nitrate production and tumoricidal
effect. These data suggest the involvement of NO in pancreatic tumour growth and
support the fact that generation of high levels of NO with potential production
of endogenous reactive nitrogen intermediates may contribute to induction of
apoptosis and tumour growth inhibition.
PMID- 9764575
TI - Inhibition by transforming growth factor (34-43)-alpha, a TGF-alpha antagonist,
of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in
Wistar rats.
AB - The effect of prolonged administration of transforming growth factor (34-43)
alpha, an antagonist of TGF-alpha, on gastric carcinogenesis induced by N-methyl
N'-nitro-N-nitrosoguanidine (MNNG) and on the labelling and apoptotic indices and
TGF-alpha immunoreactivity of gastric mucosa and gastric cancers was examined in
Wistar rats. The rats received intraperitoneal injections of 10 or 20 microg kg(
1) body weight of TGF(34-43)-alpha every other day after oral treatment with MNNG
for 25 weeks. Long-term administration of TGF(34-43)-alpha at both doses
significantly reduced the incidence of gastric cancers at the end of the
experiment in week 52. However, TGF(34-43)-alpha had no significant effect on the
number, histological type or depth of involvement of gastric cancers.
Administration of TGF(34-43)-alpha also significantly decreased the
bromodeoxyuridine labelling index and TGF-alpha immunoreactivity, and
significantly increased the apoptotic index of antral mucosa and gastric cancers.
These findings indicate that TGF(34-43)-alpha inhibits gastric carcinogenesis,
and that its effects are mediated through decreased cell proliferation and TGF
alpha immunoreactivity and increased apoptosis induction in the gastric cancers.
PMID- 9764574
TI - Mechanism of muscle protein degradation induced by a cancer cachectic factor.
AB - A proteolysis-inducing factor (PIF) isolated from a cachexia-inducing murine
tumour (MAC16) produced a decrease in body weight (1.6 g, P < or = 0.01 compared
with control subjects) within 24 h after i.v. administration to non-tumour
bearing mice. Weight loss was associated with significant decreases in the weight
of the spleen and soleus and gastrocnemius muscles, with no effect on the weight
of the heart or kidney and with an increase in weight of the liver. Protein
degradation in isolated soleus muscle was significantly increased in mice bearing
the MAC16 tumour. To define which proteolytic pathways contribute to this
increase, soleus muscles from mice bearing the MAC16 tumour and non-tumour
bearing animals administered PIF were incubated under conditions that modify
different proteolytic systems. In mice bearing the MAC16 tumour, there were
increases in both cathepsin B and L, and the Ca2+-dependent lysosomal and ATP
dependent pathways were found to contribute to the increased proteolysis;
whereas, in PIF-injected animals, there was activation only of the ATP-dependent
pathway. Further studies in mice bearing the MAC16 tumour have provided evidence
for increased levels of ubiquitin-conjugated proteins and increased mRNA levels
for the 14 kDa ubiquitin carrier protein E2 and the C9 proteasome subunit in
gastrocnemius muscle, suggesting activation of the ATP-ubiquitin-dependent
proteolytic pathway. A monoclonal antibody to PIF attenuated the enhanced protein
degradation in soleus muscle from mice bearing the MAC16 tumour, confirming that
PIF is responsible for the loss of skeletal muscle in cachectic mice.
PMID- 9764576
TI - Autocrine self-elimination of cultured ovarian cancer cells by tumour necrosis
factor alpha (TNF-alpha).
AB - Human ovarian adenocarcinoma cells N.1 secrete an autocrine activity that
stimulates active cell death under serum-reduced conditions. To substitute the
autocrine activity by a single physiological component, 28 cytokines, growth
factors and biomodulators were tested [interleukin 1alpha (IL-1alpha), IL-1beta,
IL-2, IL-3, IL-4, IL-6, IL-10, IL-11, stem cell factor (SCF), platelet-derived
growth factor (PDGF), acid fibroblast growth factor (aFGF), basic fibroblast
growth factor (bFGF), insulin-like growth factor (IGF-1), IGF-2, insulin,
macrophage colony-stimulating factor (M-CSF), granulocyte colony-stimulating
factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF),
oncostatin, RANTES (regulated on activation normal T cell expressed and
secreted), angiogenin, leukaemia inhibitory factor (LIF), erythropoietin (EPO),
interferon alpha (INF-alpha), INF-gamma, transferrin, tumour necrosis factor
alpha (TNF-alpha, TNF-beta and bovine serum albumin for control reasons]. In
these experiments, only TNF-alpha and TNF-beta rapidly induced apoptosis. TNF
alpha and TNF-receptor 1 were expressed by N.1 cells, and the secretion of TNF
alpha was verified by enzyme-linked immunosorbent assay (ELISA). Autocrine factor
triggered apoptosis was inhibited when conditioned supernatant was preincubated
with anti-TNF-alpha antibody. These findings suggested that the apoptosis
inducing component of the N.1 autocrine activity was TNF-alpha. In the presence
of antisense c-myc oligonucleotides, induction of cell death by autocrine factor
was partly inhibited. Autocrine factor and TNF-alpha stimulated transcription of
the invasiveness-related protease plasminogen activator/urokinase mRNA (upa) with
similar kinetics. When N.1 cells were exposed to purified plasminogen
activator/urokinase protein (uPA), cell matrix contact was disrupted. Thus, uPA
might serve a physiological role during TNF-induced apoptosis by affecting the
interactions between cells and the basal membrane, thereby facilitating anoikis.
This mechanistic study, which was restricted to a single human ovarian carcinoma
model cell line (N.1), provides evidence that N.1 maintains the capacity to
undergo c-myc-dependent apoptosis by the TNF-TNF-receptor pathway, and no
additional pharmacological stimuli for induction of apoptosis are required.
PMID- 9764577
TI - Tau expression in model adenocarcinomas correlates with docetaxel sensitivity in
tumour-bearing mice.
AB - Docetaxel is a new taxoid with clinical activity in breast and lung cancer. Using
docetaxel-sensitive and -refractory mammary and pancreatic murine tumours, as
well as human-derived neoplasms, we investigated if a determinant of docetaxel
sensitivity could be found at the level of its mechanism of action. Because
microtubules represent the cellular targets of the drug, we studied their
heterogeneity in the tumour models to try to explain the differences in drug
sensitivity. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of
the expression of microtubular components showed that levels of Mbeta4-tubulin
and Tau mRNAs were higher in the murine sensitive neoplasms than in the
refractory ones. It was also found that Tau protein levels differed markedly
among the tumours. In the human-derived sensitive neoplasm, beta-tubulins and
some Tau isoforms were found to be more abundant than in the resistant one.
Western blot analysis of MAP2 revealed the presence of several immunoreactive
species. Some of these polypeptides were also found in higher amounts in the
docetaxel-sensitive tumours. The possible meaning of these correlations is
discussed in connection with the regulation of microtubule dynamics.
PMID- 9764578
TI - Establishment of a retinoic acid-resistant human acute promyelocytic leukaemia
(APL) model in human granulocyte-macrophage colony-stimulating factor (hGM-CSF)
transgenic severe combined immunodeficiency (SCID) mice.
AB - To understand the mechanisms and identify novel approaches to overcoming retinoic
acid (RA) resistance in acute promyelocytic leukaemia (APL), we established the
first human RA-resistant APL model in severe combined immunodeficiency (SCID)
mice. UF-1 cells, an RA-resistant APL cell line established in our laboratory,
were transplanted into human granulocyte-macrophage colony-stimulating factor (GM
CSF)-producing SCID (hGMTg SCID) mice and inoculated cells formed subcutaneous
tumours in all hGMTg SCID mice, but not in the non-transgenic control SCID mice.
Single-cell suspensions (UF-1/GMTg SCID cells) were similar in morphological,
immunological, cytogenetic and molecular genetic features to parental UF-1 cells.
All-trans RA did not change the morphological features of cells or their
expression of CD11b. RA did not alter the growth curve of cells as determined by
MTT assay, suggesting that UF-1/GMTg SCID cells are resistant to RA. These
results demonstrate that this is the first RA-resistant APL animal model that may
be useful for investigating the biology of this myeloid leukaemia in vivo, as
well as for evaluating novel therapeutic approaches including patients with RA
resistant APL.
PMID- 9764579
TI - Reversal of P-glycoprotein-mediated multidrug resistance by XR9051, a novel
diketopiperazine derivative.
AB - XR9051 (N-(4-(2-(6,7-Dimethoxy-1,2,3,4-tetrahydro-2-isoquinolyl)ethyl)phe nyl)-3
((3Z,6Z)-6-benzylidene-1-methyl-2,5-dioxo-3-pipera zinylidene) methylbenzamide)
was identified as a potent modulator of P-glycoprotein-mediated multidrug
resistance (MDR) following a synthetic chemistry programme based on a natural
product lead compound. The activity of XR9051 was determined using a panel of
human and murine drug-resistant cell lines (H69/LX4, 2780AD, EMT6/AR 1.0, MC26
and P388/DX Johnson). XR9051 was able to reverse resistance to a variety of
cytotoxic drugs, including doxorubicin, etoposide and vincristine, which are
associated with classical MDR. At a concentration of 0.3-0.5 microM, XR9051 was
able to fully sensitize resistant cells to cytotoxics, whereas little or no
effect was observed on the corresponding parental cell lines. No effect of XR9051
was observed on the response of cells to non-MDR cytotoxics such as methotrexate
and 5-fluorouracil. XR9051 was consistently more potent than cyclosporin A (CsA)
and verapamil (Vpm) in all assays used. XR9051 inhibited the efflux of
[3H]daunorubicin from preloaded cells and, unlike CsA and Vpm, remained active
for several hours after removal of resistance-modifying agent. In photoaffinity
labelling experiments employing [3H]azidopine, XR9051 was able to displace
binding to P-glycoprotein. In binding studies using [3H]vinblastine, XR9051 was
shown to be a potent inhibitor of the binding of the cytotoxic to P-glycoprotein
(EC50 = 1.4 +/- 0.5 nM). Taken together, the results indicate that XR9051
reverses the MDR phenotype through direct interaction with P-glycoprotein.
PMID- 9764580
TI - Fraction of radiobiologically hypoxic cells in human melanoma xenografts measured
by using single-cell survival, tumour growth delay and local tumour control as
end points.
AB - Four human melanoma xenograft lines (A-07, D-12, R-18, U-25) grown orthotopically
in Balb/c nu/nu mice were characterized with respect to the fraction of
radiobiologically hypoxic cells. The purpose of the study was to establish a firm
radiobiological basis for future use of the lines in the development and
evaluation of non-invasive assays of tumour hypoxia. The hypoxic fractions were
assessed using three different assays, the single cell survival assay, the tumour
growth delay assay and the local tumour control assay, and the means +/- s.e.
were found to be 6 +/- 3%, 3 +/- 1% and 5 +/- 2% respectively (A-07), 26 +/- 5%,
25 +/- 6% and 22 +/- 6% respectively (D-12), 55 +/- 9%, 65 +/- 8% and 48 +/- 7%
respectively (R-18) and 52 +/- 8%, 59 +/- 7% and 47 +/- 7% respectively (U-25).
The three assays gave numerical values for the hypoxic fraction that were not
significantly different for any of the lines. The hypoxic fraction differed
significantly among the lines; the R-18 and U-25 lines showed higher hypoxic
fractions than the D-12 line (P < 0.05), which in turn showed a higher hypoxic
fraction than the A-07 line (P < 0.05), regardless of the assay. The wide range
of the hypoxic fractions and the significant differences among the lines suggest
that A-07, D-12. R-18 and U-25 tumours should be useful models in future studies
attempting to develop non-invasive assays of tumour hypoxia.
PMID- 9764581
TI - Fatigue and radiotherapy: (A) experience in patients undergoing treatment.
AB - Cancer patients undergoing radiotherapy frequently report fatigue. However,
knowledge of the importance of fatigue for these patients and of the factors
associated with their fatigue is limited. The aim of the current investigation
was to gain more insight into fatigue as related to radiotherapy by answering the
following questions. First, how is the experience of fatigue best described?
Secondly, to what extent is fatigue related to sociodemographic, medical
(including treatment), physical and psychological factors? Finally, is it
possible to predict which patients will suffer from fatigue after completion of
radiotherapy? Patients with different types of cancer receiving radiotherapy with
curative intent (n = 250) were interviewed before and within 2 weeks of
completion of radiotherapy. During treatment, patients rated their fatigue at 2
weekly intervals. Results indicate a gradual increase in fatigue over the period
of radiotherapy and a decrease after completion of treatment. Fatigue scores
obtained after radiotherapy were only slightly, although significantly, higher
than pretreatment scores. After treatment, 46% of the patients reported fatigue
among the three symptoms that caused them most distress. Significant associations
were found between post-treatment fatigue and diagnosis, physical distress,
functional disability, quality of sleep, psychological distress and depression.
No association was found between fatigue and treatment or personality
characteristics. Multivariate regression analysis demonstrated that the intensity
of pretreatment fatigue was the best predictor of fatigue after treatment. In
view of this finding, a regression analysis was performed to gain more insight
into the variables predicting pretreatment fatigue. The degree of functional
disability and impaired quality of sleep were found to explain 38% of the
variance in fatigue before starting radiotherapy. Fatigue in disease-free
patients 9 months after treatment is described in paper (B) in this issue.
PMID- 9764582
TI - Fatigue and radiotherapy: (B) experience in patients 9 months following
treatment.
AB - Little is known regarding the prevalence and course of fatigue in cancer patients
after treatment has ended and no recurrence found. The present study examines
fatigue in disease-free cancer patients after being treated with radiotherapy (n
= 154). The following questions are addressed. First, how do patients describe
their fatigue 9 months after radiotherapy and is this different from fatigue in a
nonselective sample from the general population (n = 139)? Secondly, to what
degree is fatigue in patients associated with sociodemographic, medical, physical
and psychological factors? Finally, is it possible to predict which patients will
suffer from fatigue 9 months after radiotherapy? Results indicated that fatigue
in disease-free cancer patients did not differ significantly from fatigue in the
general population. However, for 34% of the patients, fatigue following treatment
was worse than anticipated, 39% listed fatigue as one of the three symptoms
causing them most distress, 26% of patients worried about their fatigue and
patients' overall quality of life was negatively related to fatigue (r = -0.46).
Fatigue in disease-free patients was significantly associated with: gender,
physical distress, pain rating, sleep quality, functional disability,
psychological distress and depression, but not with medical (diagnosis,
prognosis, co-morbidity) or treatment-related (target area, total radiation dose,
fractionation) variables. The degree of fatigue, functional disability and pain
before radiotherapy were the best predictors of fatigue at 9-month follow-up,
explaining 30%, 3% and 4% of the variance respectively. These findings are in
line with the associations found with fatigue during treatment as reported in the
preceding paper in this issue. The significant associations between fatigue and
both psychological and physical variables demonstrate the complex aetiology of
this symptom in patients and point out the necessity of a multidisciplinary
approach for its treatment.
PMID- 9764583
TI - High-dose chemotherapy followed by reinfusion of selected CD34+ peripheral blood
cells in patients with poor-prognosis breast cancer: a randomized multicentre
study.
AB - Seventy-one patients with poor-prognosis breast cancer were enrolled after
informed consent in a multicentre randomized study to evaluate the use of
selected peripheral blood CD34+ cells to support haematopoietic recovery
following high-dose chemotherapy. Patients who responded to conventional
chemotherapy were mobilized with chemotherapy (mainly high-dose cyclophosphamide)
and/or recombinant human granulocyte colony-stimulating factor (rhG-CSF).
Patients who reached the threshold of 20 CD34+ cells per microl of peripheral
blood underwent apheresis and were randomized at that time to receive either
unmanipulated mobilized blood cells or selected CD34+ cells. For patients in the
study arm, CD34+ cells were selected from aphereses using the Isolex300 device.
Fifteen patients failed to mobilize peripheral blood progenitors and nine other
patients were excluded for various reasons. Forty-seven eligible patients were
randomized into two comparable groups. CD34+ cells were selected from aphereses
in the study group. Haematopoietic recovery occurred at similar times in both
groups. No side-effect related to the infusion of selected cells was observed.
The frequency of epithelial tumour cells in aphereses was low (8 out of 42
evaluated patients), as determined by immunocytochemistry. We conclude that
selected CD34+ cells safely support haematopoietic recovery following high-dose
chemotherapy in patients with poor-prognosis breast cancer.
PMID- 9764584
TI - Heterozygosity for mutations in the ataxia telangiectasia gene is not a major
cause of radiotherapy complications in breast cancer patients.
AB - Of patients being treated by radiotherapy for cancer, a small proportion develop
marked long-term radiation damage. It is believed that this is due, at least in
part, to intrinsic individual differences in radiosensitivity, but the underlying
mechanism is unknown. Individuals affected by the recessive disease ataxia
telangiectasia (AT) exhibit extreme sensitivity to ionizing radiation. Cells from
such individuals are also radiosensitive in in vitro assays, and cells from AT
heterozygotes are reported to show in vitro radiosensitivity at an intermediate
level between homozygotes and control subjects. In order to examine the
possibility that a defect in the ATM gene may account for a proportion of
radiotherapy complications, 41 breast cancer patients developing marked changes
in breast appearance after radiotherapy and 39 control subjects who showed no
clinically detectable reaction after radiotherapy were screened for mutations in
the ATM gene. One out of 41 cases showing adverse reactions was heterozygous for
a mutation (insertion A at NT 898) that is predicted to generate a truncated
protein of 251 amino acids. No truncating mutations were detected in the control
subjects. On the basis of this result, the estimated percentage (95% confidence
interval) of AT heterozygous patients in radiosensitive cases was 2.4% (0.1
12.9%) and in control subjects (0-9.0%). We conclude that ATM gene defects are
not the major cause of radiotherapy complications in women with breast cancer.
PMID- 9764585
TI - High-dose etoposide with granulocyte colony-stimulating factor for mobilization
of peripheral blood progenitor cells: efficacy and toxicity at three dose levels.
AB - High-dose etoposide (2.0-2.4 g m(-2)) with granulocyte colony-stimulating factor
(G-CSF) is an effective strategy to mobilize peripheral blood progenitor cells
(PBPCs), although in some patients this is associated with significant toxicity.
Sixty-three patients with malignancy were enrolled into this non-randomized
sequential study. The majority (55/63, 87%) had received at least two prior
regimens of chemotherapy, and seven patients had previously failed to mobilize
following high-dose cyclophosphamide with G-CSF. Consecutive patient groups
received etoposide at three dose levels [2.0 g m(-2) (n = 22), 1.8 g m(-2) (n =
20) and 1.6 g m(-2) (n = 21)] followed by daily G-CSF. Subsequent leukaphereses
were assayed for CD34+ cell content, with a target total collection of 2.0 x
10(6) CD34+ cells kg(-1). Toxicity was assessed by the development of significant
mucositis, the requirement for parenteral antibiotics or blood component support
and rehospitalization incidence. Ten patients (16%) had less than the minimum
target yield collected. Median collections in the three groups were 4.7 (2 g m(
2)), 5.7 (1.8 g m(-2)) and 6.5 (1.6 g m(-2)) x 10(6) CD34+ cells kg(-1). Five of
the seven patients who had previously failed cyclophosphamide mobilization
achieved more than the target yield. Rehospitalization incidence was
significantly lower in patients receiving 1.6 g m(-2) etoposide than in those
receiving 2.0 g m(-2) (P = 0.03). These data suggest that high-dose etoposide
with G-CSF is an efficient mobilization regimen in the majority of heavily
pretreated patients, including those who have previously failed on high-dose
cyclophosphamide with G-CSF. An etoposide dose of 1.6 g m(-2) appears to be as
effective as higher doses but less toxic.
PMID- 9764586
TI - Telomerase activity and human papillomavirus in malignant, premalignant and
benign cervical lesions.
AB - The purpose of this study was to define a correlation between telomerase activity
and human papillomavirus (HPV) in normal control tissue and in benign,
premalignant and malignant cervical lesions. Telomerase activity was detectable
in 33 out of 34 cases of squamous-cell carcinoma, five out of six cases of
microinvasive carcinoma, 8 out of 20 cases and two out of six cases of high- and
low-grade squamous intraepithelial lesions (SILs) respectively. The higher
frequency of positive telomerase in invasive carcinoma compared with SILs was
observed in both HPV-associated and non-associated groups. Whereas 92.6% of HPV
positive and 100% of HPV-negative invasive lesions expressed telomerase, only 50%
of HPV-positive and 25% of HPV-negative SILs did. Interestingly, telomerase
activity was also detectable in 13 out of 28 cases of benign lesions regardless
of the presence of HPV. In conclusion, there may be two roles of telomerase in
the cervix. The first one would present in benign lesions; the second is
associated with cancer development and activated during the late stage of
multistep carcinogenesis in both HPV-positive and -negative groups.
PMID- 9764587
TI - Microvessel density predicts survival in prostate cancer patients subjected to
watchful waiting.
AB - The biological potential of prostate cancer is highly variable and cannot be
satisfactorily predicted by histopathological criteria alone. Angiogenesis, the
formation of new blood vessels, has been suggested to provide important
prognostic information in prostate cancer. The aim of this study was to
investigate whether microvessel density (MVD) at diagnosis was correlated with
disease-specific survival in a non-curative treated population of prostate cancer
patients. MVD was immunohistochemically (factor VIII-related antigen) quantified
in archival tumours obtained at diagnosis in 221 prostate cancer patients. Median
length of follow-up was 15 years. The maximal MVD was quantified inside a 0.25
mm2 area of the tumour and the median MVD was 43 (range 16-151) mm2. MVD was
statistically significantly correlated with clinical stage (P < 0.0001) and
histopathological grade (P < 0.0001). When dichotomized by the median counts, MVD
was shown to be significantly associated (P = 0.0001) with disease-specific
survival in the entire population as well as in the theoretically curable
clinically localized subpopulation. A multivariate analysis demonstrated that MVD
was a significant predictor of disease-specific survival in the entire cancer
population (P = 0.0004), as well as in the clinically localized cancer population
(P < 0.0001). These findings suggest that quantitation of angiogenesis reflects
the spontaneous clinical outcome of prostate cancer.
PMID- 9764588
TI - Epithelial proliferation and hormone receptor status in the normal post
menopausal breast and the effects of hormone replacement therapy.
AB - The proliferation rate (as assessed by Ki67 expression) and expression of
oestrogen-regulated progesterone receptor (PR) was studied in normal post
menopausal breast epithelium. Normal breast epithelium from patients receiving
hormone replacement therapy (HRT) at the time of surgery containing either
oestrogen alone (E2) or oestrogen and progesterone combined activities (E2 + P)
was also studied, as HRT has been linked to an increased breast cancer risk.
Samples of breast tissue, containing normal epithelium, from 185 patients
undergoing surgery for benign or malignant disease were immunocytochemically
stained for PR and Ki67. The percentage of labelled cells was expressed as the
labelling index (LI). The median Ki67 LI in normal post-menopausal breast
epithelium was 0.19 and median PR LI was 4.75, and both were unaffected by
patient age, duration of menopause or if the tissue sample originated from a
breast with benign or malignant disease. Proliferation did not alter
significantly in patients taking HRT (P = 0.61); however, PR expression was up
regulated in both E2 and E2 + P users (P = 0.01). The dose and duration of HRT
had no effect on either parameter. A possible attenuation of sensitivity to
oestradiol-induced proliferation but not to PR expression occurs in the post
menopausal breast.
PMID- 9764589
TI - Allelotype analysis of oesophageal adenocarcinoma: loss of heterozygosity occurs
at multiple sites.
AB - Deletions of tumour-suppressor genes can be detected by loss of heterozygosity
(LOH) studies, which were performed on 23 cases of adenocarcinoma of the
oesophagus, using 120 microsatellite primers covering all non-acrocentric
autosomal chromosome arms. The chromosomal arms most frequently demonstrating LOH
were 3p (64% of tumours), 5q (45%), 9p (52%), 11p (61%), 13q (50%), 17p (96%),
17q (55%) and 18q (70%). LOH on 3p, 9p, 13q, 17p and 18q occurred mainly within
the loci of the VHL, CDKN2, Rb, TP53 and DCC tumour-suppressor genes
respectively. LOH on 5q occurred at the sites of the MSH3 mismatch repair gene
and the APC tumour-suppressor gene. 11p15.5 and 17q25-qter represented areas of
greatest LOH on chromosomes 11p and 17q, and are putative sites of novel tumour
suppressor genes. LOH on 9p was significantly associated with LOH on 5q, and
tumours demonstrating LOH at both the CDKN2 (9p21) and MSH3 (5q11-q12) genes had
a significantly higher fractional allele loss than those retaining heterozygosity
at these sites. Six of nine carcinomas displaying microsatellite alterations also
demonstrated LOH at CDKN2, which may be associated with widespread genomic
instability. Overall, there are nine sites of LOH associated with oesophageal
adenocarcinoma.
PMID- 9764590
TI - The incidence of cancers among second-generation Irish living in England and
Wales.
AB - The incidence of ovarian, cervical, lung and prostatic cancer was higher in
second-generation Irish living in England and Wales than in all other persons in
England and Wales. A higher incidence of ovarian cancer was not found in first
generation Irish. Differences in socioeconomic status did not explain these
patterns.
PMID- 9764591
TI - Seventeen-year evaluation of breast cancer screening: the DOM project, The
Netherlands. Diagnostisch Onderzoek (investigation) Mammacarcinoom.
AB - The DOM project is a non-randomized population-based breast cancer screening
programme in Utrecht which started in 1974-75. The 17-year effect has been
evaluated by a case-control study of breast cancer deaths during the period 1975
92 in women living in the city of Utrecht, born between 1911 and 1925, whose
breast cancers were diagnosed after the initiation of the DOM project. Controls
(three for each case) were defined as women having the same year of birth as the
case, living in the city of Utrecht at the time the case died, and having had the
opportunity of screening in the DOM project. Screening in the period 1975-92
indicated a breast cancer mortality reduction of 46% (odds ratio of 0.54, 95%
confidence interval 0.37-0.79). The strongest protective effect was found at a
screening interval of 2 years or less (mortality reduction of 62%, odds ratio of
0.38), and for the highest number of screens (mortality reduction of 68%, odds
ratio of 0.32 for more than four screens). Exclusion of breast cancer deaths that
occurred within 1 year of diagnosis, to allow for 'lead-time' bias, gave an odds
ratio of 0.61. Early diagnosis of breast cancer by screening reduces breast
cancer mortality in the long term. Bias due to the study design may slightly
overestimate the protective effect. A screening programme with a 2-yearly, or
smaller, interval between successive screens will improve the protection of
screening.
PMID- 9764592
TI - Risk of cancer other than Kaposi's sarcoma and non-Hodgkin's lymphoma in persons
with AIDS in Italy. Cancer and AIDS Registry Linkage Study.
AB - Record linkage was carried out between the national Registry of AIDS and 13
Cancer Registries (CRs) covering, in 1991, about 15% of the Italian population.
Observed and expected numbers of cancers and standardized incidence ratios (SIRs)
were assessed in 6067 persons with AIDS, for a total of 25,759 person-years.
Significantly increased SIRs were found for Hodgkin's disease [8.9, 95%
confidence interval (CI) 4.4-16.0], in which seven of 11 cases were of mixed
cellularity type; invasive carcinoma of the cervix uteri (15.5; 95% CI 4.0-40.1);
and non-melanomatous skin cancer (3.0, 95% CI 1.3-5.9), in which five of eight
cases were basal cell carcinoma. An excess was also seen for brain tumours, but
this may be partly due to misdiagnosis of brain non-Hodgkin's lymphoma or other
brain diseases occurring near the time of the AIDS diagnosis. The risk for all
cancer types, after exclusion of Kaposi's sarcoma (KS) and non-Hodgkin's lymphoma
(NHL), was approximately twice the general population risk. An increased SIR for
Hodgkin's disease in persons with AIDS is thus confirmed, though it is many times
smaller than that for NHL. An association with invasive carcinoma of the cervix
is also shown at a population level. The excess of non-melanomatous skin cancer
seems to be lower than in transplant recipients.
PMID- 9764593
TI - Overexpression of p53 in different subtypes of intestinal metaplasia and gastric
cancer.
AB - p53 immunostaining was evaluated in cancerous epithelia and adjacent intestinal
metaplasia of 135 gastric cancer specimens. The differential p53 overexpression
in different subtypes of intestinal metaplasia and gastric cancer suggests that
type III intestinal metaplasia is the commonest lesion in dysplasia-carcinoma
transition, particularly in the intestinal type of gastric cancer.
PMID- 9764594
TI - Epidemiology of childhood brain tumours in Yorkshire, UK, 1974-95: geographical
distribution and changing patterns of occurrence.
AB - From a high-quality population-based register of children with cancer, 455 cases
diagnosed with central nervous system (CNS) tumours were analysed to examine
patterns of occurrence and geographical distribution. There was a significant
increase of 1.8% (95% CI 0.5-3.1, P < 0.01) in average annual incidence for all
CNS tumours, mainly accounted for by a 3.1% rise (95% CI 0.1-6.1, P < 0.05) in
primitive neuroectodermal tumours (PNETs) over the 22-year period 1974-95. These
increases were not explained by an increase in the proportion of histologically
verified tumours. In the most recent time period (1986-95), astrocytomas occurred
more commonly than previously in 0 to 4-year olds. Geographical differences in
incidence were evident at a large scale, between counties, for all tumours and
astrocytomas, with lower rates in the most urbanized areas. At the level of
census district and electoral wards, no association between incidence of CNS
tumours and socioeconomic group, person-based population density or ethnicity was
observed using Poisson regression modelling. Based on small-scale census
geography, the patterns of distribution of CNS tumours do not suggest strong
associations with geographical determinants of risk. This study finds a rising
incidence of all CNS tumours and particularly primitive neuroectodermal tumours
and shows that astrocytomas appear to be occurring at a younger age, most
probably because of improved diagnosis with non-invasive technology.
PMID- 9764595
TI - Regulation of cytokine expression by an autoreactive B cell clone derived from
MRL/MP-lpr/lpr mice.
AB - The B cell line, MRL159.5, was established by somatic hybridization between
splenic MRL/MP-lpr/lpr (lpr) mice B cells and 2.52M, a hypoxanthine-aminopterine
thymidine (HAT) medium-sensitive B cell line mutant. It possessed a receptor
molecule for mouse erythrocytes treated with bromelain (Br-MRBC) on its surface,
likely to be an autoreactive B cell clone specific for Br-MRBC as detected by
rosette-forming assay with Br-MRBC. MRL159.5 spontaneously produced IL-6 and
secreted IgM, and was induced to augment IgM secretion when treated with Br-MRBC
or IL-6. Triggering of CD40 led to an augmentation of IgM secretion as well as IL
6 expression. Blocking the binding of IL-6 to its cellular receptor through the
use of inhibitory antibodies inhibited CD40-induced IgM secretion, suggesting a
possible autocrine role of IL-6 for CD40-induced differentiation of this B cell
hybridoma. Addition of IL-4 or Br-MRBC augmented IL-6 expression as well as IgM
secretion by CD40-activated MRL159.5 cells. CD40 also augmented tumour necrosis
factor-alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM
CSF) expression but resulted in decreased IL-10 expression. Furthermore, under
conditions where IL-6 expression was augmented, IL-6R alpha (gp80) expression was
down-regulated, suggesting a negative feedback mechanism of an IL-6 autocrine
loop in this hybridoma. These results demonstrate a role by which T cell
dependent activation through CD40 regulates an IL-6 autocrine loop, controlling
differentiation of autoreactive B cells in autoimmune disease.
PMID- 9764596
TI - Mercury-induced autoimmunity in the absence of IL-4.
AB - In susceptible H-2S mice, mercuric chloride (HgCl2) induces an autoimmune
syndrome characterized by production of anti-nucleolar antibodies (ANoA) and
increased serum levels of IgG1 and IgE antibodies. The increase in serum IgG1 and
IgE, which are under IL-4 control, suggests a role for the Th2 subset in the
induction of this syndrome. We have previously shown that administration of IL
12, a potent Th1-promoting cytokine, resulted in a dramatic reduction of the
HgCl2-induced anti-nucleolar antibody titres and inhibited serum IgG1 increase.
These results suggest that Th1 T cells can down-regulate ANoA, and support a role
for the Th2 subset in ANoA production, possibly via IL-4. To examine the role of
IL-4 in this syndrome, C57Bl/6 mice (H-2b) with a targeted deletion of the IL-4
gene were mated with A.SW mice (H-2S) to yield H-2S mice lacking IL-4. We then
analysed ANoA and serum immunoglobulin levels in these mice after HgCl2
treatment. While mercury-treated IL-4(-/-) H-2S mice had virtually no detectable
serum IgG1 or IgE, and very low levels of IgG1 ANoA, these mice had levels of
IgG2a and IgG2b class ANoA comparable to mercury-treated IL-4+ H-2S mice,
indicating that IL-4 is not required for the ANoA response in mercury-induced
autoimmunity.
PMID- 9764597
TI - Macrophage function in alloxan diabetic mice: expression of adhesion molecules,
generation of monokines and oxygen and NO radicals.
AB - The increased incidence of bacterial and mycotic infections in poorly controlled
diabetic patients or animals is frequently attributed to impaired activities of
professional phagocytes (granulocytes, macrophages) in hypoinsulinaemic milieu.
We measured production of monokines (IL-6 and tumour necrosis factor-alpha (TNF
alpha)), active NO and reactive oxygen intermediates (ROIs), as well as
expression of several cell surface adhesion molecules (Mac-1, -2 and -3,
intercellular adhesion molecule-1 (ICAM-1) and Fc gammaRII), by thioglycollate
medium-induced peritoneal macrophages of normoglycaemic and alloxan diabetic
CBA/J mice (blood glucose level in the range 300 or 500 mg/dl). Macrophages of
animals with moderate diabetes (300 mg/dl) produced significantly more IL-6 and
TNF-alpha and ROIs than cells of control mice and showed an increased expression
of all cell surface molecules, except Mac-3. NO/NO2 production was not affected.
Administration of insulin restored enhanced values to normal levels, except for
the production of ROIs which remained unusually high. We conclude that two
separate mechanisms influence macrophage physiology in diabetes--lack of
saturation of insulin receptors on macrophages and an indirect effect due to
formation of advanced glycosylation endproducts (AGE) on their surfaces. The
latter is possibly responsible for increased generation of ROIs, since it cannot
be down-regulated by prolonged insulin treatment. How the increased activity of
macrophages of moderately diabetic mice (enhanced production of proinflammatory
monokines and oxygen radicals as well as expression of molecules) is related to
their ability to kill bacteria is now under investigation.
PMID- 9764598
TI - Accumulation of immunoglobulin-containing cells in the gut mucosa and presence of
faecal immunoglobulin in severe combined immunodeficient (scid) mice with T cell
induced inflammatory bowel disease (IBD).
AB - Scid mice transplanted either with a gut wall graft or with low numbers of
purified CD4+ T cells from immunocompetent syngeneic donor mice show clinical
signs of IBD 3-4 months post-transplantation. The disease is mediated by mucosa
infiltrating CD4+ TCR alphabeta+ T cells. The pathology of 52 individual colon
segments obtained from 20 gut wall- or CD4+ T cell-transplanted diseased scid
mice was evaluated by histology and the numbers of infiltrating immunoglobulin
containing cells were determined. In particular, cells positive for IgM, IgA and
non-inflammatory immunoglobulin isotypes such as IgG1 and IgG2b were found to
accumulate in colon segments displaying the most severe histopathology, including
inflammatory cellular infiltration, epithelial hyperplasia and ulcerative
lesions. Compared with colon segments of normal C.B-17 mice, the lesional scid
colon shows increased levels of cells positive for the IgG classes. Faecal
extracts of the CD4+ T cell-transplanted scid mice revealed the presence of all
six murine immunoglobulin isotypes. Disease progression was accompanied by an
increased level of excreted IgM and IgG3 and decreased levels of IgA. It is
concluded that locally secreted immunoglobulins may play an immunomodulating role
in the pathological changes observed in the present model of T cell-induced
inflammatory bowel disease.
PMID- 9764599
TI - Perioperative cytokine release during coronary artery bypass grafting in patients
of different ages.
AB - Surgical interventions and cardiopulmonary bypass (CPB) induce a systemic
inflammatory response with cytokine release. Ageing is perceived as a process of
impaired immune functions: IL-1beta, IL-6 and tumour necrosis factor-alpha (TNF
alpha) secretion are increased while IL-2 release is reduced in advanced age. At
present, little information is available about perioperative immune reactions at
different stages of ageing. The aim of the present study was to compare IL-6, IL
1beta, TNF-alpha, IL-10 and soluble IL-2 receptor (sIL-2R) in younger and older
patients undergoing cardiac surgery. Male patients (n = 14) undergoing elective
coronary artery bypass grafting (CABG) surgery employing CPB with moderate
hypothermia were divided into two groups according to their age: group 1 included
seven patients < 50 years old, group 2 included seven patients > 65 years old.
All patients received general anaesthesia using a balanced technique with
sufentanil, isoflurane and midazolam. Blood samples were collected pre
operatively (T1); intra-operatively during CPB (T2); post-operatively on the day
of surgery (T3); on the first post-operative day (T4). Blood concentrations of IL
6, IL-1beta, IL-10, TNF-alpha and sIL-2R were measured using commercially
available ELISA kits and corrected for plasma cell volume. Statistical analysis
was performed by non-parametric analysis of variance and Mann-Whitney U-test.
Significance level was set to P<0.05. There were no statistically significant
differences in the perioperative release of TNF-alpha, IL-6, IL-1beta, IL-10 and
sIL-2R among the two groups. We conclude that the perioperative course of
cytokine release in patients undergoing CABG surgery with CPB and comparable
perioperative management does not significantly differ in the two age groups.
PMID- 9764600
TI - Somatic mutation of immunoglobulin V(H)6 genes in human infants.
AB - Infants respond to antigen by making antibody that is generally of low affinity
for antigen. Somatic hypermutation of immunoglobulin genes, and selection of
cells expressing mutations with improved affinity for antigen, are the molecular
and cellular processes underlying the maturation of antibody affinity. We have
reported previously that neonates and infants up to 2 months of age, including
individuals undergoing strong immunological challenge, show very few mutated
V(H)6 sequences, with low mutation frequencies in mutated sequences, and little
evidence of selection. We have now examined immunoglobulin genes from healthy
infants between 2 and 10 months old for mutation and evidence of selection. In
this age group, the proportion of V(H)6 sequences which are mutated and the
mutation frequency in mutated sequences increase with age. There is evidence of
selection from 6 months old. These results indicate that the process of affinity
maturation, which depends on cognate T-B cell interaction and functional germinal
centres, is approaching maturity from 6 months old.
PMID- 9764601
TI - Evidence of idiotypic modulation in the immune response to gp43, the major
antigenic component of Paracoccidioides brasiliensis in both mice and humans.
AB - Paracoccidioidomycosis (PCM) is a systemic mycosis endemic in Latin America, with
a high prevalence in Brazil, Argentina, Colombia and Venezuela. The aetiologic
agent of disease is a thermal dimorphic fungus, Paracoccidioides brasiliensis. A
glycoprotein of 43,000 D (gp43) is the major antigen of P. brasiliensis.
Antibodies directed to this antigen are detected in the sera of all patients with
PCM. Gp43 binds to laminin, thus participating in adhesion, invasion and
pathogenesis of the fungus. As the role of antibodies in PCM is not fully
understood, we decided to investigate the outcome of mice immunization with three
distinct anti-gp43 MoAbs (17c, 8a and 24a) coupled with keyhole limpet
haemocyanin (KLH). Results show not only the expected presence of anti-Id (AB2)
antibodies in the sera of these animals but also a spontaneous and increasing
amount of anti-anti-Id (AB3) antibodies after the third course of immunization.
Hybridomas producing both AB2 and AB3 MoAbs were obtained using spleen cells from
mice immunized with MoAb 17c. AB3 MoAbs were also obtained with spleen cells of
mice immunized with MoAbs 8a and 24a. It was also shown that human PCM patients'
sera with high titres of anti-gp43 antibodies generate anti-Id antibodies. These
data suggest that the immune response to P. brasiliensis can be spontaneously
modulated by the idiotypic network.
PMID- 9764602
TI - The apoptosis of neutrophils is accelerated in respiratory syncytial virus (RSV)
induced bronchiolitis.
AB - Neutrophils are the predominant inflammatory cell in the lung tissues and airways
in RSV infection, and can augment the epithelial cell damage induced by RSV.
Neutrophil apoptosis has been suggested to be a mechanism to reduce the potential
for tissue injury. The apoptosis of neutrophils from nasopharyngeal aspirates
(NPA) (n = 19) and peripheral blood (PB) of infants with RSV bronchiolitis (n =
11) and PB from healthy controls (n = 9) was investigated. Monoclonal antibody
against CD95 (Fas) and a binding protein Annexin V were used to determine the
apoptosis of neutrophils. The expression of CD11b and CD18 on neutrophils was
also detected with flow cytometry. The mean fluorescence intensity (MFI) of CD95
on neutrophils from RSV+ NPA was increased compared with cells from control PB
(73.6 +/- 7.6 versus 31.5 +/- 4.3); the MFI of Annexin V, CD11b and CD18 on
neutrophils from RSV+ NPA was up-regulated compared with cells from both control
PB (105.3 +/- 18.1 versus 11.8 +/- 1.5; 1683 +/- 153.3 versus 841.1 +/- 72.3; 517
+/- 50.5 versus 147 +/- 8.7, respectively) and RSV+ PB (105.3 +/- 18.1 versus
35.8 +/- 4.1; 1683 +/- 153.3 versus 818 +/- 141.2; 517 +/- 50.5 versus 260 +/-
25.8, respectively). Furthermore, the percentage of neutrophils expressing
Annexin V and the MFI of CD18 on neutrophils from RSV+ PB were increased compared
with neutrophils from control PB. In addition, both CD11b (MFI) and CD18 (MFI)
correlated with Annexin V (MFI) on neutrophils. We conclude that neutrophil
apoptosis in RSV bronchiolitis is accelerated; and CD11b/CD18 may play an
important role in RSV infection by influencing neutrophil apoptosis.
PMID- 9764603
TI - mRNA cytokine profile in peripheral blood cells from chronic hepatitis C virus
(HCV)-infected patients: effects of interferon-alpha (IFN-alpha) treatment.
AB - Natural immune responses, both cellular and humoral, are not capable of
terminating HCV infection in most patients. A role has been suggested for
peripheral blood leucocytes (PBL) in viral persistence and clinical implications,
as these cells may serve as a viral reservoir and at the same time may be
inadequate active participants in antiviral immune reactions. IFN-alpha
administration, although only partially successful, is currently the main therapy
available for chronic HCV patients. In addition to its antiviral effects, IFN
alpha regulates the function of cytokines, their receptors and other molecules of
immune importance. The aim of this study was to determine cytokine mRNA
expression in PBL derived from chronic HCV patients prior to and at termination
of IFN-alpha treatment. HCV RNA was still observed in sera of most patients (10
out of 14 treated patients) at termination of treatment. In pretreated patients
mRNA expression of Th2 (IL-4, IL-6 and IL-10) and Th3 (transforming growth factor
beta (TGF-beta)) was observed in only a low percentage of PBL samples from
patients, similar to controls. IFN-alpha treatment led to an elevation in the
number of samples expressing these cytokines (significant for IL-4, IL-6, IL-10,
tumour necrosis factor-alpha (TNF-alpha) and TGF-beta), accompanied by reduction
in liver enzymes but in serum viral load in only approximately 30% of patients.
Expression of TNF-alpha and TNF-beta mRNA was observed in samples from patients
but not controls, while no differences were observed for mRNA of classical Th1
cytokines (IL-2 and IFN-gamma) between patients before or during treatment as
well as controls. The cytokine mRNA profile following IFN-alpha treatment points
to an anti-inflammatory response which does not appear to be involved in
termination of the viral infection. The PBL cytokine profile observed in this
study may explain the failure of the immune system to eradicate HCV chronic
infection and suggests that early treatment in the acute phase of disease with
agents that stimulate cytotoxic immune type 1 responses may lead to eradication
of HCV infection.
PMID- 9764604
TI - Tumour necrosis factor (TNF) and TNF-related molecules in HIV-1+ individuals:
relationship with in vitro Th1/Th2-type response.
AB - We examined the secretion and expression by peripheral blood mononuclear cells
(PBMC) of TNF-alpha and TNF-related molecules with regard to Th1/Th2-type
cytokine production. In 76 HIV+ patients at different disease stages and in 25
controls we measured cytokine (TNF-alpha/beta, interferon-gamma (IFN-gamma), IL
2, IL-4, IL-10), and activation marker secretion (sCD4, sCD8, sCD30) in
phytohaemagglutinin (PHA)-stimulated and unstimulated PBMC cultures by ELISA, and
membrane-bound TNF-alpha and CD30 expression by flow cytometry. We found an
expansion of the TNF system in HIV+ individuals, that positively correlated with
TNF-alpha, IFN-gamma and sCD8, probably representing activation of the cytotoxic
compartment. In advanced disease these correlations disappeared, and TNF-alpha
and TNF-related molecules positively correlated with IL-10. Our results are in
line with the hypothesis that an expanded TNF system is immunopathological in
conjunction with Th2-type immunity in the advanced stage of disease and with the
inexorable progression to disease seen when both IL-10 and TNF-alpha are
elevated.
PMID- 9764605
TI - Expression of the activation antigen CD69 predicts functionality of in vitro
expanded peripheral blood mononuclear cells (PBMC) from healthy donors and HIV
infected patients.
AB - Gene therapy for AIDS necessitates harvest and expansion of PBMC from HIV
infected patients. We expanded PBMC from healthy blood donors and HIV-infected
patients for up to 14 days using four expansion protocols: 3 days of
phytohaemagglutinin (PHA) stimulation, continuous PHA stimulation, 3 days of
stimulation with anti-CD3 and anti-CD28, and continuous stimulation with anti-CD3
and anti-CD28. Functionality of PBMC was evaluated prior to and after expansion
using standard proliferation assay. Phenotype and lymphocyte subset activation
defined by expression of CD69 and CD25 were determined using flow cytometry. PBMC
from healthy donors and HIV-infected patients were readily expanded. The best
expansion was obtained using stimulation for 3 days. After expansion,
functionality of PBMC measured as proliferative response was partly conserved.
PBMC expanded with stimulation for 3 days exhibited more preserved functionality
than PBMC stimulated continuously (P < 0.03). The mean proliferative response in
each of the four different expansion protocols correlated with the mean values of
CD69 expression. The proliferative responses from patients and healthy donors
expanded with PHA stimulation for 3 days correlated with CD69 expression on CD4
cells (r = 0.68, P < 0.01) and on CD8 cells (r = 0.59, P < 0.03). Furthermore,
expression of CD69 reliably predicted which patients and donors had highly
conserved functionality after in vitro expansion. Finally, PBMC expanded with PHA
stimulation for 3 days were examined for apoptosis. Only a minor fraction was
primed for apoptosis, and this fraction could be significantly reduced by
addition of IL-2 to the culture medium (P < 0.05). In conclusion, the feasibility
of expanding PBMC from HIV patients was demonstrated. Expanded PBMC had conserved
functionality. Finally, after in vitro expansion, expression of the activation
antigen CD69 reliably predicted functionality of PBMC.
PMID- 9764606
TI - Neutrophil adhesion molecules in HIV disease.
AB - Neutrophil dysfunction in HIV disease is well described. We examined the
expression of neutrophil adhesion molecules amongst 72 HIV-infected subjects
using a whole blood flow cytometric assay with FITC- and R-PE-labelled isotype
specific MoAbs. We report lesser expression of CD11a (LFA-1) and L-selectin
(CD62L) on the circulating neutrophils of HIV+ subjects compared with HIV-
controls. Expression of CD11b (Mac-1) was unchanged. Shedding of L-selectin and
up-regulation of CD11b in response to in vitro stimulation with N-formyl
methionyl-leucyl-phenylalanine (fMLP) were less in HIV+ compared with HIV-
subjects, most markedly in subjects with CD4 cell counts < 100 cells/mm3. These
results suggest that neutrophil dysfunction in HIV disease, which increases with
disease progression, may be attributable to dysregulated adhesion molecule
expression.
PMID- 9764607
TI - Differential production of IL-10 by T cells and monocytes of HIV-infected
individuals: association of IL-10 production with CD28-mediated immune
responsiveness.
AB - Immune unresponsiveness in HIV-1 infection can result from impaired signals
delivered by the costimulatory CD28-B7 pathway and the altered production of
immunoregulatory cytokines, in particular IL-10, whose production is altered in
HIV-1 infection. In this study we investigate IL-10 regulation in T cells and
monocytes from HIV+ individuals, and its association with CD28-mediated T cell
proliferation. IL-10 production as analysed in T cell- and monocyte-depleted
peripheral blood mononuclear cells (PBMC), and by intracellular staining at the
single-cell level, reveals a defect in IL-10 production by CD4+ and CD8+ T cells,
whereas monocytes constitute the major IL-10-producing cell type. To investigate
the impact of IL-10 on immune responsiveness, CD28-mediated proliferative
responses in HIV+ individuals were correlated with PHA-induced IL-10 production.
CD4+ T cells expressed CD28, yet exhibited markedly reduced CD28-mediated cell
proliferation. This CD28-mediated CD4+ T cell proliferation was found to be
inversely associated with the levels of PHA-induced IL-10 production and could be
restored, at least in part, by anti-IL-10 antibodies. These results suggest that
IL-10 production is differentially regulated in T cells and monocytes of HIV+
individuals, and that IL-10 may have a role in inducing immune unresponsiveness
by modulating the CD28-B7 pathway.
PMID- 9764608
TI - Enhancement of HIV-1 replication in human macrophages is induced by CD8+ T cell
soluble factors.
AB - We previously reported that CD8+ T cell-derived factors enhanced HIV long
terminal repeat (LTR)-mediated gene expression and replication in monocytic cell
lines. We now report that replication of NSI and SI primary isolates of HIV-1 in
human macrophages were significantly enhanced by CD8+ T cell supernatants. The
CD8-mediated enhancement of HIV replication was abrogated by pertussis toxin in a
dose-dependent manner. The sensitivity to pertussis toxin suggests that the CD8+
T cell-derived enhancing factor is acting through a G protein-coupled signalling
pathway. Enhanced HIV replication in macrophages was accompanied by increased
levels of HIV-1 mRNA, suggesting that CD8 enhancement was mediated at the
transcriptional level. Interestingly, the replication of HIV(Bal), which
replicates to high levels in macrophages, was not significantly modulated by
culture with CD8+ T cell supernatants. Although direct co-culture of activated
CD8+ T cells with HIV(Ada)-infected macrophages did not modulate replication,
separation of the CD8+ T cells from macrophages in transwell cultures resulted in
significant enhancement of replication. The inability to detect a modulatory
effect in direct co-cultures appeared to be due to non-specific lysis of infected
macrophages. Thus, soluble factors produced by CD8+ T cells exert strong
enhancing effects on HIV-1 replication in human macrophages.
PMID- 9764609
TI - Increased nitric oxide (NO) production by antigen-presenting dendritic cells is
responsible for low allogeneic mixed leucocyte reaction (MLR) in primary biliary
cirrhosis (PBC).
AB - The levels of blastogenesis in allogeneic MLR containing T cells from one normal
volunteer and irradiated dendritic cells from 29 patients with PBC, 17 patients
with chronic hepatitis type C (CH-C) and 22 allogeneic normal controls were
compared to see if there is any role of antigen-presenting cells (APC) in the
pathogenesis of PBC. The stimulatory capacity of dendritic cells from PBC was
significantly lower compared with that of dendritic cells from CH-C (P < 0.05)
and normal controls (P < 0.05), which could not be attributable either to the
levels of expression of surface molecules, such as HLA-DR and CD86 on dendritic
cells, or to the levels of cytokines, such as IL-10 and IL-12. Significantly
higher levels of NO were seen in the allogeneic MLR supernatants containing
dendritic cells from PBC compared with the supernatants from cultures containing
dendritic cells from CH-C (P < 0.001) or normal controls (P < 0.001). Moreover,
dendritic cells from PBC produced 10 times more NO compared with dendritic cells
from CH-C and normal controls (21.9 +/- 2.8 microM versus 1.6 +/- 0.3 microM and
1.6 +/- 0.3 microM, respectively; P < 0.001). The addition of N(G)-monomethyl-L
arginine monoacetate (L-NMMA), a known inhibitor of NO in allogeneic MLR
containing dendritic cells from PBC, resulted in a significant decrease of NO and
increase of blastogenesis. The selective impairment of dendritic cell function,
increased production of NO by dendritic cells and restoration of blastogenesis
using NO inhibitor in PBC have suggested a role for NO and dysfunction of
dendritic cells in the pathogenesis of PBC. This inspires optimism that
modulating the function of dendritic cells and controlling NO production, an
improved therapeutic approach, might be planned for PBC.
PMID- 9764610
TI - Soluble complement receptor type 1 (sCR1) in chronic liver diseases: serum levels
at different stages of liver diseases.
AB - Complement receptor type 1 (CR1) is an integral membrane protein of many
haematopoietic cells and plays an important role in the clearance of complement
associated immune complexes, favouring their transport to liver and spleen
macrophages. A small amount of soluble CR1 (sCR1) is also found in plasma and
might originate directly from release of leucocytes and other circulating cells.
In previous studies, an increase in serum sCR1 level has been observed in liver
cirrhosis and end-stage renal failure. High levels have also been found in
patients with some haematologic malignancies. sCR1 serum levels were measured
using a specific double sandwich ELISA assay. The present study demonstrates the
correlation between mean serum sCR1 concentrations and disease severity in
patients with chronic liver disease. In patients with liver cirrhosis, grouped
according to the Child-Pugh classification, sCR1 rose as liver function
decreased. The presence of neoplastic growth in the liver apparently does not
play a role in the increase of sCR1. Serum sCR1 was not elevated in other solid
malignancies. Since sCR1 accumulates in liver diseases, evaluation of its serum
levels could be useful as a liver function test.
PMID- 9764611
TI - Apoptosis in labial salivary glands from Sjogren's syndrome (SS) patients:
comparison with human T lymphotropic virus-I (HTLV-I)-seronegative and
seropositive SS patients.
AB - Apoptosis is a type of cell death that occurs during morphogenesis and
development of the immune system. One of the mechanisms is mediated through the
Fas and Fas ligand (FasL) pathway. To determine the possible involvement of Fas
and its ligand in salivary gland destruction, we analysed the appearance of
nuclei with DNA fragmentation by using nick end labelling (TUNEL) and the
expression of Fas and FasL by immunohistochemistry in labial salivary glands.
Furthermore, we compared the features of apoptosis in labial salivary glands
between HTLV-I- and HTLV-I+ SS. When the frozen sections of 10 primary SS
patients in the absence of anti-HTLV-I antibody were examined, several apoptotic
cells were found in the acinar and ductal epithelial cells as well as infiltrated
mononuclear cells. Both Fas and FasL were detected in the infiltrated mononuclear
cells. Acinar epithelial cells, which are surrounded by FasL+ mononuclear cells,
were also double-positive with Fas and FasL, although the expression of FasL was
localized at their apical border, suggesting that apoptosis of mononuclear cells
was achieved by activation-induced mechanisms through Fas/FasL pathways, and that
of acinar epithelial cells was mediated by FasL derived from either acinar
epithelial cells themselves or infiltrated mononuclear cells. Interestingly, Fas
expression in ductal epithelial cells was localized around the lumen side of the
ducts, indicating that FasL secreted from acinar epithelial cells may induce Fas
mediated apoptosis of ductal epithelial cells. We also studied the labial
salivary glands from nine SS patients with anti-HTLV-I antibodies. There was no
significant difference in the occurrence of apoptotic cells or in the expression
of Fas and FasL between HTLV-I+ and HTLV-I- SS patients. It was of note that
neither the expression of Fas and FasL nor the presence of apoptotic cells were
determined in labial salivary glands from subjects without SS. These findings
indicate that Fas-mediated apoptosis in salivary glands could be involved in the
pathological manifestations of SS, irrespective of HTLV-I seropositivity.
PMID- 9764612
TI - Costimulatory molecules in Wegener's granulomatosis (WG): lack of expression of
CD28 and preferential up-regulation of its ligands B7-1 (CD80) and B7-2 (CD86) on
T cells.
AB - T cells are most likely to play an important role in the pathogenesis of WG, and
recently a predominant Th1 pattern of immune response has been demonstrated in
granulomatous inflammation. Since the expression of costimulatory molecules has a
significant impact on the cytokine profile and proliferation response of T cells,
the goal of this study was to characterize the expression of costimulatory
molecules (CD28, CTLA-4 (CD152), B7-1 (CD80), B7-2 (CD86)) on T cells, monocytes
and B cells in WG, and to correlate the findings with clinical parameters such as
disease activity, extent and therapy. WG patients (n = 24) and healthy controls
(HC; n = 17) were examined for the expression of costimulatory molecules by
fluorescence-activated cell sorter analysis, both in whole peripheral blood and
after in vitro activation of T cells and antigen-presenting cells. Results were
correlated with clinical data. The expression of CD28 on CD4+ and CD8+ cells was
significantly lower in WG than in HC (CD28+ 81.4% in WG versus 97.9% of CD4+
cells (P < 0.0001); CD28+ 44.6% in WG versus 68.5% of CD8+ cells (P < 0.00001)),
both in peripheral blood and after in vitro activation. A lower percentage of
monocytes was B7-2+ in WG than in HC in peripheral blood, whereas no significant
differences in the expression of B7-1 and B7-2 were observed after in vitro
stimulation of monocytes and B cells. After in vitro activation a significantly
higher percentage of B7-1+ and B7-2+ T cells was seen in WG. There was no
significant difference in the CTLA-4 expression pattern between WG and HC. The
percentage of CD28+ lymphocytes correlated negatively with the Disease Extent
Index cumulated over the course of disease (r = -0.46, P = 0.03), indicating a
more severe manifestation in patients with lower CD28 expression. Correlations
with other clinical parameters such as activity or therapy were not seen. WG
patients show a lack of CD28 expression on T cells and an unusual up-regulation
of its ligands B7-1 and B7-2 on T cells after in vitro activation as well as a
lower expression of B7-2 on freshly isolated monocytes compared with HC. These
features might promote the Th1 cytokine pattern and thereby contribute to
persistently high levels of immune activation in WG.
PMID- 9764613
TI - Modulation by proinflammatory cytokines of Fas/Fas ligand-mediated apoptotic cell
death of synovial cells in patients with rheumatoid arthritis (RA).
AB - Synovial cell hyperplasia is a characteristic of patients with RA. Excessive
proliferation of RA synovial cells is, in part, responsible for the synovial cell
hyperplasia. In addition, synovial cell death that would reduce synovial cell
number may be defective, leading to the hyperplasia. Thus, the defective control
of cell death as well as cell proliferation may be of central importance in the
pathogenesis of RA. In this study we analysed effects of proinflammatory
cytokines on Fas/Fas ligand (FasL)-induced synovial cell apoptosis, and evaluated
apoptosis-associated protein expression in the synovial cells in patients with
RA. RA synovial cells expressed Fas antigen and lymphocytes infiltrating into RA
synovium expressed FasL. Apoptotic synovial cells were detected within the
sublining layer of RA synovium. Anti-Fas MoAb induced apoptosis of RA synovial
cells in vitro, and proinflammatory cytokines tumour necrosis factor-alpha (TNF
alpha) and IL-1beta, but not IL-6 or IL-8, inhibited the anti-Fas-induced
apoptosis accompanying up-regulation of Bcl-2 protein expression and reduced
expression of CPP32 and ICH-1L. Immunohistochemical study revealed that CPP32 and
ICH-1L were expressed weakly in the RA synovial lining cells compared with
osteoarthritis (OA) synovial lining cells. Thus, we found that although RA
synovial cells could die via apoptosis through Fas/FasL pathway, apoptosis of
synovial cells was inhibited by proinflammatory cytokines present within the
synovium. Inhibition of apoptosis by the proinflammatory cytokines may contribute
outgrowth of synovial cells that leads to pannus formation and the destruction of
joints in patients with RA.
PMID- 9764614
TI - Sequence analysis of V(4-34)-encoded antibodies from single B cells of two
patients with systemic lupus erythematosus (SLE).
AB - SLE is an autoimmune disease characterized by the presence of autoantibodies
against double-stranded (ds)DNA. A large proportion (approx. 40%) of patients
with lupus also have increased levels of serum immunoglobulin encoded by the V(4
34) heavy chain gene, which often fluctuate with disease activity, and this gene
is utilized by a subset of anti-dsDNA antibodies. In order to probe the nature of
the V(4-34)-encoded immunoglobulin, B cells were isolated from the blood of two
patients with active disease, using the 9G4 MoAb specific for the immunoglobulin
gene product. Following cell picking, single-cell polymerase chain reaction (PCR)
amplification of cDNA was used to investigate both V(H) and V(L) genes. Sequences
were obtained from B cells synthesizing IgM (n = 10), IgG (n = 4) and IgA (n =
1). For V(H), all were derived from V(4-34) as expected, and the isotype-switched
sequences and 2/6 IgM sequences were somatically mutated. In contrast, V(L) (12
kappa and 3 lambda) showed a low level of mutation, possibly indicating secondary
rearrangements. The three most highly mutated V(H) sequences were associated with
unmutated V(L) sequences. Analysis of the distribution of mutations revealed only
minor clustering in complementarity-determining regions (CDRs) characteristic of
antigen selection. The CDR3 lengths of V(H) ranged from five to 19 amino acids,
and in 3/15 there was evidence of an excess of positively charged amino acids,
compared with the normal expressed repertoire. Basic amino acids were also found
at the V(L)-J(L) junctions in 4/15. These findings provide insight into the V(4
34)-V(L) gene combinations used by B cells in patients with SLE which might have
clinical relevance.
PMID- 9764615
TI - A masked randomized comparison of oral and vaginal administration of misoprostol
for labor induction.
AB - OBJECTIVE: To test the null hypothesis that administering misoprostol orally or
vaginally will result in no difference in time to vaginal birth, and to determine
whether different frequencies of tachysystole and hyperstimulation are associated
with route of administration. METHODS: Two hundred six women after 37 completed
weeks' gestation who presented with an indication for induction were randomly
assigned to receive misoprostol (50 microg) either orally or vaginally every 4
hours as needed to induce labor. Placebo use and allocation concealment
accomplished blinding until data analysis was completed. Sample size was
calculated to allow a two-tailed alpha of .05 and power (1-beta) of 80%. All
fetal heart rate and uterine activity graphs were classified according to Curtis'
criteria before induction groups were unmasked. RESULTS: Analysis involved 104
women in the oral group and 102 in the vaginal group. The mean time (+/-standard
deviation) to vaginal birth with oral misoprostol was 1072 (+/-593) minutes
compared with 846 (+/-385) minutes with the vaginal protocol (P=.004). There were
no significant differences in cesarean rate, epidural use, or neonatal outcomes.
More frequent tachysystole for 20 minutes (P < .01) and hyperstimulation (P <
.04) were observed with vaginal misoprostol. No neonatal asphyxia occurred in
either group. CONCLUSION: Misoprostol effectively induces labor, given orally or
vaginally. There is a shorter interval to vaginal birth with vaginal application;
however, the more frequent occurrence of fetal heart rate graph abnormalities in
this group suggests that, until the optimal dosing interval for vaginal use is
determined, the preferred route of misoprostol administration might be oral.
PMID- 9764616
TI - Cervical ripening with mifepristone before labor induction: a randomized study.
AB - OBJECTIVE: To determine the efficacy and safety of mifepristone for cervical
ripening in post-term pregnancies. METHODS: Women with post-term pregnancies and
Bishop scores less than 6 were assigned randomly to mifepristone (41 patients) or
placebo (42 patients). Mifepristone was given orally in a dose of 400 mg.
Efficacy was assessed by change in the Bishop score within 48 hours after
treatment; a score of 6 or greater was considered a "strict" success. An
"extended" success rate was defined, including all patients with scores of at
least 6 or those who delivered within 48 hours of treatment. Antenatal safety was
assessed by fetal heart rate testing before and throughout labor. Neonatal safety
was assessed by Apgar score, arterial or venous pH of cord blood, and blood
glucose level during the first 48 hours. Analysis used Student t test for
continuous variables, Kruskal-Wallis test for ordinal data, and chi2 for
categoric variables. RESULTS: Strict success was achieved in 10 of 18
mifepristone patients (55%) evaluated for Bishop score on day 2 versus 8 of 29
placebo patients (27.5%) (P=.004). Extended success was achieved in 33
mifepristone patients (80.5%) and 21 placebo patients (50.0%) (P=.004). There
were no statistical differences with regard to number of cesareans or fetal and
neonatal safety. CONCLUSION: Mifepristone proved effective for cervical ripening
and reduced the time to delivery compared with placebo, but it did not improve
the rate of cesarean. Our study did not include enough pregnancies to reach
conclusions about fetal or neonatal safety.
PMID- 9764617
TI - The cost-effectiveness of routine type and screen admission testing for expected
vaginal delivery.
AB - OBJECTIVE: To evaluate the cost effectiveness of routine admission type and
screen testing for expected vaginal delivery. METHODS: A retrospective review was
conducted in patients transfused with blood during an admission that anticipated
a vaginal delivery over a 3-year period, at Hutzel Hospital, in Detroit,
Michigan. RESULTS: Of 16,291 patients admitted for an expectant vaginal delivery,
76 (.47%) (95% confidence interval [CI] .37%, .58%) required blood transfusion
during the time of their admission. Medical records of these 76 patients were
evaluated as to urgency and risk factors. Most of the blood transfusions were
related to previously identified risk factors, including previous postpartum
hemorrhage, multiple pregnancies, previous cesarean delivery, abruptio placentae,
and admission anemia. Four patients received an urgent blood transfusion without
a previously identifiable risk factor. We found an overall urgent blood
transfusion rate without admission risk factors to be 2.5 per 10,000 vaginal
deliveries (95% CI .9 per 10,000, 6.3 per 10,000) CONCLUSION: Routine admission
type and screen testing for an expected normal vaginal delivery does not seem to
enhance patient care and should be eliminated for patients without substantial
risk factors. In the rare event that a patient without a previously identified
risk factor required an urgent blood transfusion, O negative blood could be given
in the interim pending formal type and cross match.
PMID- 9764618
TI - Cesarean delivery and anal sphincter injury.
AB - OBJECTIVE: Cesarean delivery has been thought to prevent all obstetric anal
sphincter damage. The objective of this study was to determine the relationship
between the timing of cesarean during primiparous delivery and injury to the anal
sphincter mechanism. METHODS: A prospective observational study was conducted,
using a continence questionnaire and anorectal physiology assessment before and
six weeks after primiparous delivery. A cohort of 234 women were recruited from
the antenatal clinics at the National Maternity Hospital, Dublin. Thirty-four
women delivered subsequently by cesarean, and 200 women by spontaneous vaginal
delivery. RESULTS: Thirty-four women underwent cesarean delivery without
attempted vaginal delivery: eight prior to labor and 26 during labor, 17 in early
labor (cervical dilatation less than 8 cm) and 9 in late labor (dilatation
greater than 8 cm). No woman delivered by cesarean had altered fecal continence
postpartum. Anorectal physiology was unaltered in women delivered by elective
cesarean or cesarean in early labor. Pudendal nerve terminal motor latency was
prolonged, anal squeeze pressure increment reduced, but vector symmetry index was
unchanged in women delivered by cesarean delivery late in labor, indicating
neurologic injury to the anal sphincter mechanism. CONCLUSION: Cesarean delivery
performed in late labor, even in the absence of attempted vaginal delivery, does
not protect the anal sphincter mechanism.
PMID- 9764619
TI - Obstacles to reducing cesarean rates in a low-cesarean setting: the effect of
maternal age, height, and weight.
AB - OBJECTIVE: To examine risk factors for elective and nonelective cesarean delivery
in a population with a low cesarean rate. METHODS: Nulliparous women delivering
singleton births in Sweden during 1992-93 were included (n=92,623). Logistic
regression analyses were performed to calculate adjusted odds ratios (ORs) and
rates of cesarean delivery. RESULTS: The overall cesarean rate was 11.9%. Risks
for cesarean increased consistently with increasing maternal age, decreasing
maternal height, and increasing prepregnancy body mass index (BMI). Compared with
teenagers, the OR of cesarean was 2.6 among women 30-34 years and 4.4 among women
35 years of age or older. Compared with tall women (greater than 174 cm), the OR
of cesarean for women 155-164 cm was 2.0, and 4.5 for short women (less than 155
cm). Compared with lean women (BMI less than 20.0), the ORs of cesarean for
overweight (BMI 25.0-29.9) and obese women (BMI of at least 30.0) were 1.8 and
2.4, respectively. Similar risks also were obtained when the analyses were
restricted to elective or nonelective cesarean deliveries. The effect of
prepregnancy BMI on cesarean rate was influenced by maternal height: among tall
women, rates of cesarean increased from 5% among lean women to 11% among obese
women, whereas corresponding rates among short women were 19% and 36%,
respectively. The influence of mother's education, type of hospital, and other
factors was considerably less. CONCLUSION: The increase in maternal age at first
birth and the weight among young women present obstacles to the reduction of
cesarean rates in developed countries.
PMID- 9764620
TI - Maternal and infant complications in high and normal weight infants by method of
delivery.
AB - OBJECTIVE: To estimate the population risks of maternal and infant complications
with the birth of macrosomic (at least 4000 g) compared with normal weight
infants. METHODS: Term, singleton infants were identified from the state of
Washington's birth event records database for 1990. Diagnosis codes from the
Internal Classification of Diseases (9th revision) were used to identify delivery
method and previously defined complications. We adjusted for maternal demographic
and clinical factors using multivariable logistic regression to derive the risk
of each maternal and infant complication. RESULTS: The incidence of macrosomia
was 13% (8815 of 66,086). Vaginal birth of macrosomic infants was associated with
low incidence of complications except for shoulder dystocia (11%) and postpartum
hemorrhage (5%). Postpartum infection was the most common complication for women
who had cesarean delivery after labor (5%), and complications for women who had
cesarean without labor were rare (less than 3%). Neonatal complications were
rare. Among infants with shoulder dystocia, the risks of asphyxia (adjusted
relative risk [RR] 1.2, 95% confidence interval [CI] 0.6, 2.3), birth trauma (RR
0.6, 95% CI 0.2, 1.6), long-bone injury (RR 1.2, 95% CI 0.6, 2.4), seizures (RR
1.0, 95% CI 0.0, 25.0), and facial palsy (RR 2.2, 95% CI 0.2, 44.4) were not
significantly different for macrosomic and normal weight infants; however,
macrosomic infants had a significantly increased risk of Erb palsy (RR 3.5, 95%
CI 1.8, 7.5). CONCLUSION: This population-based study showed that most macrosomic
infants are delivered vaginally with low rates of maternal and neonatal
complications. Macrosomic infants have higher rates of Erb palsy, but similar
rates of other serious complications of shoulder dystocia when compared with
normal weight infants.
PMID- 9764621
TI - Regional differences in operative obstetrics: a look to the South.
AB - OBJECTIVE: To compare operative delivery rates across regions of the United
States from 1987 to 1994 and to evaluate how the rates of severe obstetric
lacerations changed during the same period. METHODS: I used diagnosis and
procedure data from the National Hospital Discharge Survey and natality data from
the National Center for Health Statistics to describe temporal and regional
variations in the rates of cesarean, forceps, and vacuum delivery. I described
temporal trends in the rates of cervical and severe perineal lacerations during
the same period. I performed exploratory analyses of detailed 1990 data to test
for regional differences in demographic risk factors that might explain
differences in operative delivery rates. RESULTS: Between 1987 and 1994, cesarean
delivery rates fell from approximately 25% to less than 22% in all regions except
the South. Operative vaginal delivery rates were stable at 10-12% and were
consistently lowest in the Northeast (8.2% in 1994) and highest in the South
(12.9% in 1994). Vacuum surpassed forceps deliveries in all regions except the
South. The rates of cervical and fourth-degree perineal lacerations declined by
57% and 40%, respectively, whereas the rate of third-degree lacerations did not
decline. Demographic risk factors for cesarean delivery were no more prevalent in
the South than in other regions. Age under 25 years was the only demographic risk
factor for forceps delivery that was more prevalent in the South. CONCLUSION: In
all but the southern United States, cesarean delivery rates declined and vacuum
surpassed forceps delivery. These regional differences are not explained by
differences in demographic risk factors.
PMID- 9764622
TI - Management of extremely low birth weight infants: perceptions of viability and
parental counseling practices.
AB - OBJECTIVE: To determine physician opinions, parental counseling, and medical
practices for extremely low birth weight (LBW) infants. METHODS: A retrospective
survey was sent in August 1996 to 450 California physicians practicing
obstetrics. RESULTS: There was a 41% response rate. The mean thresholds for
antenatal steroid administration, cesarean delivery for fetal distress and
delivery room resuscitation were gestational age between 23 and 24 weeks and
weight close to 500 g. Most obstetricians counsel parents regarding survival,
resuscitation, and possible death in the delivery room before delivery of an
extremely LBW infant. Just over 60% of obstetricians believe that parents have a
role in deciding not to resuscitate an infant born at 22 weeks' gestation, this
decreases to less than 50% at 24 weeks, and decreases further to less than 30% by
26 weeks' gestation. Just over 40% of obstetricians report their counseling is
affected by pediatric opinion, 33% by previous maternal perinatal losses, and
less than 20% by maternal drug use or lack of prenatal care, and young maternal
age. Language barriers, parental education level, and family insurance affect
treatment options in less than 10% of obstetricians. CONCLUSION: Obstetric
opinions about delivery room resuscitation of extremely LBW infants are
influenced by birth weight and gestational age thresholds, infant, and parental
factors. There is a limited willingness by physicians to allow a parental role in
decision making in the delivery room for extremely LBW infants.
PMID- 9764623
TI - Effect of maternal hydration on oligohydramnios: a comparison of three volume
expansion methods.
AB - OBJECTIVE: To determine the effect of maternal hydration with intravenous (i.v.)
isotonic fluid, i.v. hypotonic fluid, and oral water on amniotic fluid index
(AFI) in women with oligohydramnios. METHODS: Patients with low AFI and
gestational age over 35 weeks without maternal complications were randomized into
four groups (2 L/2 h i.v. isotonic fluid, 2 L/2 h i.v. hypotonic fluid, 2 L/2 h
oral water, control). Maternal plasma osmolality, AFI, hematocrit, and hemoglobin
concentration were measured before and after hydration. RESULTS: Eighty-four
patients (n=21/group) completed the study without any maternal adverse effects.
The mean increase in AFI after hydration was significantly greater in the i.v.
hypotonic and oral water groups (2.8+/-1.9, P < .001; 3.8 +/-1.9, P < .001,
respectively), but not in the i.v. isotonic group (0.5+/-1.1), compared with the
control group (0.5+/-1.1). Significant decreases in maternal hematocrit and
hemoglobin concentration were found only after i.v. isotonic hydration (32.0+/
2.9 to 29.5+/-2.3, P < .001; 11.0+/-1.6 to 10.1+/-1.4, P < .001, respectively).
Changes in maternal osmolality correlated with the changes in AFI in both the
i.v. hypotonic group (r=.58, P < .001) and oral water group (r =.63, P < .001).
CONCLUSION: Maternal hydration with either i.v. hypotonic fluid or oral water
increases AFI in oligohydramnios. Maternal osmotic change rather than maternal
volume expansion had a more direct impact on increasing amniotic fluid volume
with short-term acute hydration.
PMID- 9764624
TI - Effects of abuse on maternal complications and birth weight in adult and
adolescent women.
AB - OBJECTIVE: To estimate the incidence of physical and sexual abuse in a sample of
adult and adolescent pregnant women and to determine the relationship between
abuse and maternal complications and infant birth weight. METHODS: One thousand
eight hundred ninety-seven women were screened for abuse during pregnancy.
Maternal complications and infant birth weight were obtained by record review.
RESULTS: Physical abuse in the past year and/or during pregnancy was reported by
37.6% of the adolescent and 22.6% of the adult women (P < .001). Abused adult
women were more likely to have unplanned pregnancies (P < .001) and to begin care
after 20 weeks (P < .01) than nonabused women. For the aggregate sample of 1597
for whom birth weights were available, abuse was a significant risk factor for
low birth weight (LBW) (P < .05) as was poor obstetric history (P < .05). Using
Institute of Medicine risk factors for LBW, abused adults were more likely to
have poorer past obstetric histories and to use tobacco, alcohol, and drugs (P <
.05). Abused adolescents were at greater risk for smoking and first- or second
trimester bleeding (P < .05). For the aggregate, abused women were at greater
risk for poor obstetric history, vaginal/cervical infection during pregnancy,
smoking, and alcohol and drug use. CONCLUSION: More than one-third of the
adolescent and nearly one-fourth of the adult women reported abuse in the past
year and/or during pregnancy. Abuse is related to poor obstetric history,
substance use, and LBW. The short abuse assessment screen detects potential abuse
in order that interventions can be implemented.
PMID- 9764625
TI - Prevention of chickenpox in reproductive-age women: cost-effectiveness of routine
prenatal screening with postpartum vaccination of susceptibles.
AB - OBJECTIVE: To evaluate economic and clinical outcomes of a program of routine
prenatal serotesting for varicella and postpartum vaccination of seronegative
women. METHODS: An analytic cost-effectiveness model was constructed to compare
the current strategy of no serotesting with 1) selective serotesting of pregnant
women without a prior history of chickenpox and 2) serotesting of all pregnant
women. In both serotesting strategies, seronegative women were vaccinated
postpartum. The model followed a hypothetical cohort of 4 million women over 20
years. Costs and chickenpox disease outcomes during and outside of subsequent
pregnancies were considered. The incremental cost-effectiveness (cost per adult
chickenpox case prevented) of selective serotesting compared with the current
strategy was measured. RESULTS: Compared to no testing, selective serotesting
would prevent 43% (48,577 of 112,654) of adult chickenpox cases, save $21.8
million in discounted medical and work loss costs from the societal perspective,
and cost $1126 per case prevented from the health payer's perspective (medical
costs only). The model was sensitive to varicella seroprevalence and incidence of
chickenpox among susceptible women but was relatively insensitive to the cost of
serologic testing and vaccination. Compared with selective serotesting, the
serotest-all strategy would prevent an additional 15,645 cases, at a societal
cost of $7653 per additional case prevented. CONCLUSION: The selective
serotesting strategy could prevent nearly half of chickenpox cases among this
cohort and is cost-saving from the societal perspective. From the health payer's
perspective, it compares favorably with other generally accepted preventive
practices. It should be considered for prevention of chickenpox among women of
childbearing age.
PMID- 9764626
TI - Amniotic fluid neuron-specific enolase: a role in predicting neonatal neurologic
injury?
AB - OBJECTIVE: To determine the relationship between amniotic fluid (AF) neuron
specific enolase and the development of neonatal intraventricular hemorrhage and
periventricular leucomalacia. METHODS: Thirty-nine AF samples, obtained from
women in preterm labor between 24 and 32 weeks' gestation, were analyzed for
neuron-specific enolase. All women delivered preterm neonates who had
neurosonograms on the 3rd and 7th days of life. The results of the neurosonograms
were used to divide the study population first into normal and abnormal groups,
then into normal, minor, and major brain lesion groups. The groups were compared
for the median neuron-specific enolase, proportion with values of 6 microg/L or
more, and other demographic characteristics. RESULTS: There were no differences
between the groups' maternal and neonatal characteristics. However, the abnormal
group had significantly higher median value of neuron-specific enolase than the
normal group (9.5 microg/L and 2.0 microg/L, respectively; P < .001). The median
neuron-specific enolase levels for the major, minor, and normal groups were 9.75
microg/L, 6.5 microg/L and 2.0 microg/L, respectively (P < .001). The optimum
cutoff point, with a sensitivity of 89% and specificity of 100%, was 6 microg/L;
89% of the abnormals had values of 6 microg/L or more, compared with none of the
normals (P < .001). The risk of developing intraventricular hemorrhage or
periventricular leucomalacia was 11.5 times greater when AF neuron-specific
enolase levels were 6 microg/L or more. CONCLUSION: Amniotic fluid neuron
specific enolase is a useful marker of neonatal neurologic injury.
PMID- 9764627
TI - Factors associated with maternal cell contamination in amniocentesis samples as
evaluated by fluorescent in situ hybridization.
AB - OBJECTIVE: To determine which patient- and procedure-related factors contribute
to maternal cell contamination in uncultured amniocentesis fluid. METHODS: One
hundred thirty amniotic fluid (AF) samples were obtained by three operator
groups: maternal-fetal medicine faculty (n=50), general obstetrician
gynecologists (n=50), and obstetrics and gynecology residents supervised by
maternal-fetal medicine faculty (n=30). These groups were designated "most,"
"intermediate," and "least experience," respectively. Study variables were
recorded at the time of the procedure. Amniotic fluid cells from male fetuses
underwent fluorescent in situ hybridization. Maternal cell contamination was
calculated by analyzing 100 cells and determining the number of XX and XY cells.
A control system was created to validate the methods used for AF processing and
cell counting. RESULTS: Median maternal cell contamination was 2.0%. Maternal
cell contamination did not vary with body mass index (r=-.13, P=.14), gestational
age (r=.08, P=.35), or placental location (P=.55). Maternal cell contamination
was significantly elevated with placental penetration (6.0% compared with 1.0%, P
< .001), two passes (27.5% compared with 2.0%, P=.002), blood-tinged fluid color
(14.0% compared with 2.0%, P < .001), and operator inexperience ("intermediate
experience" compared with "most experience," 4.5% compared with 1.0%, P=.026).
Maternal cell contamination did not differ between the "most experience" and
"least experience" groups (1.0% compared with 2.0%, not significant). Concordance
between detected and actual maternal cell contamination in the control system was
extremely high (concordance coefficient=0.98, P=.008), confirming the validity of
the techniques used. CONCLUSION: Our techniques of cell counting and maternal
cell contamination calculation are accurate. Maternal cell contamination is
increased with placental penetration, two passes, and operator inexperience.
However, with expert supervision, inexperienced physicians can perform
amniocentesis without an increase in maternal cell contamination.
PMID- 9764628
TI - Cardiac dysfunction in twin-twin transfusion syndrome: a prospective,
longitudinal study.
AB - OBJECTIVE: To use serial echocardiography to evaluate prospectively the cardiac
dysfunction in twin-twin transfusion syndrome and determine its clinical course
and outcome. METHODS: Twin pregnancies presenting in the second trimester with
sonographic evidence of twin-twin transfusion syndrome were managed with
therapeutic reduction amniocenteses. Gestational age at diagnosis and delivery,
number of amniocenteses performed, volume of amniotic fluid withdrawn,
placentation, birth weight, hemoglobin at delivery, and perinatal outcome were
recorded. Serial fetal echocardiography was carried out in a single tertiary
center. Echocardiographic assessments included cardiac anatomy, chamber size,
cardiothoracic ratio, interventricular septal thickness, ventricular systolic
function, and the presence and severity of atrioventricular valve regurgitation.
Postnatal echocardiograms were obtained on the surviving twins. RESULTS: Twelve
cases of twin-twin transfusion syndrome were evaluated with serial
echocardiography. Evidence of cardiac dysfunction was present prenatally in 10
recipient twins. All of the donor twins had normal fetal echocardiographic
assessments. The most common abnormalities detected prenatally in recipient twins
were decreased ventricular function, tricuspid regurgitation, and cardiac chamber
enlargement. A deterioration of cardiac function was observed in seven recipient
twins with increasing gestational age. Four of the eight surviving recipient
twins had persistent postnatal echocardiographic abnormalities on follow-up
examinations after the first 28 days of life. CONCLUSION: Prenatal cardiac
dysfunction is common in recipient twins and can be transient, progressive, or
persistent beyond the neonatal period.
PMID- 9764629
TI - Randomized comparison of oral and transdermal hormone replacement on carotid and
uterine artery resistance to blood flow.
AB - OBJECTIVE: To compare the long-term effects of oral and transdermal hormone
replacement therapy (HRT) on carotid and uterine vascular impedance. METHODS:
Sixty-three postmenopausal women were randomized to 1 year's treatment with oral
or transdermal sequential combined HRT. Carotid and uterine artery pulsatility
indices (PIs) were assessed by color Doppler at baseline, and after 2, 6, and 12
months of treatment. Fifty-eight women completed the trial, 27 in the oral and 31
in the transdermal group. In a subgroup of 30 women, we also performed Doppler
measurements in the estrogen-progestin combined phase. The study had 90% power to
detect a difference between treatment groups of 0.05 in the carotid artery and of
0.25 in uterine artery PI at the 5% significance level. RESULTS: The carotid PI
decreased significantly (P < .001) and similarly during both regimens. This drop
was already clearly detectable during the second month, from 0.97 (0.95, 1.01)
(mean and 95% confidence intervals [CII) to 0.94 (0.91, 0.97) in the oral and
from 0.98 (0.94, 1.00) to 0.92 (0.89, 0.95) in the transdermal group, but it
continued up to 12 months (0.85 [0.82, 0.88], 13% of baseline values in the oral
group and 0.84 [0.81, 0.871, 14% in the transdermal group). In the uterine
arteries, the drop in PI was steeper and greater and reached its maximum at 6
months (39% and 40%, respectively). Drops in carotid and uterine PI correlated
positively with baseline PI values, but were not affected by patient age, time
from menopause, previous HRT and smoking. Addition of norethisterone acetate did
not counteract drops in carotid and uterine PI in either group. CONCLUSION: Oral
and transdermal sequential HRT are similarly effective at 1 year in reducing
impedance to flow in carotid and uterine circulation. This long-term vascular
effect might explain how HRT protects women from cardiovascular disease.
PMID- 9764630
TI - Spinal bone density in women using depot medroxyprogesterone contraception.
AB - OBJECTIVE: To determine factors possibly associated with reduced bone density in
women using the injectable contraceptive depot medroxyprogesterone acetate.
METHODS: In a cross-sectional study, bone mineral density of the lumbar spine was
measured by dual energy x-ray absorptiometry in 200 current users of depot
medroxyprogesterone acetate who had used this method of contraception for 2-26
years and compared with 350 control subjects. Bone density results are expressed
as standard deviation scores (z score). RESULTS: The bone density was
significantly lower in depot medroxyprogesterone acetate users (mean z score:
0.65, 95% confidence intervals [CI] -0.80, -0.49, P < .001). Bone density was
significantly reduced in nonsmokers and smokers, and there was no significant
difference in mean z score between smokers and nonsmokers (mean -0.75 versus
0.58, P=.30). Women who had started depot medroxyprogesterone acetate after the
age of 20 years and who had used it for 15 or fewer years had a significantly
higher bone density than the remainder of the cohort (mean -0.45 [95% CI -0.62,
0.27] versus -1.02 [95% CI -1.32, -0.73], P < .005). Bone density in depot
medroxyprogesterone acetate users was not related to current age, parity, body
mass index, calcium intake, or exercise. CONCLUSION: Depot medroxyprogesterone
acetate use is associated with a significant reduction in bone density, and
although a high proportion of depot medroxyprogesterone users do smoke, the
reduction in bone density cannot be explained by smoking. Women who use it for a
long time and those who start it before peak bone mass is attained may be at
highest risk.
PMID- 9764631
TI - A randomized study of tibolone on bone mineral density in osteoporotic
postmenopausal women with previous fractures.
AB - OBJECTIVE: To investigate the effects of tibolone on trabecular and cortical bone
mineral density and on indices of calcium metabolism in postmenopausal women with
previous fractures. METHODS: In a 2-year, randomized, double-blind, placebo
controlled, bicenter study, 45 women were treated with tibolone and 43 with
placebo. All subjects received 800 mg of calcium daily. Trabecular bone mineral
density of lumbar spine (L1 to L4) and cortical bone mass at the femoral neck
were assessed by dual energy x-ray absorptiometry at baseline and at 6-month
intervals. Serum and urinary bone biochemistry variables were also assessed.
RESULTS: After 2 years, subjects in the tibolone group gained 6.9% bone mass at
lumbar spine and 4.5% at femoral neck, and respective increases from baseline in
the placebo group were 2.7% and 1.4%. Tibolone-treated patients gained
statistically significantly more bone mass than placebo-treated patients in the
spine and femur. Urinary calcium: creatinine and hydroxyproline:creatinine
ratios, as well as serum alkaline phosphatase and phosphate levels, were
significantly reduced with tibolone compared with placebo. CONCLUSION: Tibolone
induced a significant increase in trabecular (lumbar spine) and cortical (femoral
neck) bone mass in postmenopausal osteoporotic women compared to placebo,
suggesting its potential to treat postmenopausal osteoporosis.
PMID- 9764632
TI - The physician's role in women's decision making about hormone replacement
therapy.
AB - OBJECTIVE: To ascertain the sources of information women use when making
decisions about hormone replacement therapy (HRT). METHODS: A cross-sectional,
population-based computer-assisted telephone survey of 1082 randomly selected
women aged 50-80 years (80.3% response rate) was conducted at Group Health
Cooperative of Puget Sound, a large staff-model health maintenance organization
in Washington state. RESULTS: Overall, 460 participants (42.5%) were current HRT
users, 226 (20.9%) were past users, and 396 (36.6%) were never users. Discussions
with physicians dominated as the major source of information used in decision
making by current (83.4%) and past (65.5%) users, but were less often cited by
never users (44.4%); printed material was used by 44.5% of women. Although 72.1%
of current users reported that the amount of information received from their
physician about the benefits of HRT was about right, only 48.2% of past users and
33.6% of never users shared this view (P < .001 current versus never), and 13.3%
of current users, 32.6% of past users and 58% of never users reported receiving
no information from their physician about HRT's benefits. CONCLUSION: Hormone
replacement therapy use is strongly related to interactions between women and
their physicians. Many women use written materials to make decisions about HRT. A
large proportion of women feel inadequately informed about HRT's risks and
benefits. Much work remains to be accomplished toward meeting the goal of the US
Preventive Services Task Force that all perimenopausal and postmenopausal women
be counseled about the potential benefits and risks of HRT.
PMID- 9764633
TI - Effect of the menstrual cycle on creatinine clearance in normally cycling women.
AB - OBJECTIVE: We assessed changes in creatinine clearance during the menstrual cycle
of normally cycling women. METHODS: We used a design that precisely identified
the day of ovulation. Creatinine clearance was measured in 14 subjects on each of
three days: cycle day 2 or 3, 1 or 2 days before the day of ovulation, and 6 or 7
days after ovulation. RESULTS: Creatinine clearance was affected significantly by
the menstrual cycle (P=.02), but the degree of this effect was modest. Mean (+/
standard error of mean) early follicular, preovulatory, and midluteal creatinine
clearance values were 135+/-4, 131+/-5, and 142+/-5 mL/min, respectively, and
only the difference between the preovulatory and midluteal values was
significant. These changes in creatinine clearance were attributable largely to
changes in creatinine excretion and not to changes in plasma creatinine
concentrations. CONCLUSION: Despite the statistically significant luteal phase
increase, creatinine clearance does not change in a clinically important manner
during the normal menstrual cycle. Specifically, there is no substantial decrease
in creatinine clearance around the time of ovulation.
PMID- 9764634
TI - Cancer among first-degree relatives of probands with invasive and borderline
ovarian cancer.
AB - OBJECTIVE: The familial clustering of ovarian, breast, endometrial, colon; and
prostate cancer was compared in first-degree relatives of probands with invasive
and borderline ovarian cancer to determine coaggregation. METHODS: Probands
(n=392), who had been patients in the Division of Gynecologic Oncology at
Washington University, were ascertained consecutively. Family history on 2192
first-degree relatives was collected by personal interviews of the probands and
other family members. Estimates of prevalence of cancers in first-degree
relatives of the two proband groups were compared. Survival analysis was used to
examine the age-at-onset distribution of each cancer in relatives of invasive
probands versus relatives of borderline probands. RESULTS: Among the relatives
were 24 cases of ovarian cancer, 46 cases of breast cancer, 13 cases of
endometrial cancer, and 25 and 28 cases of colon and prostate cancer,
respectively. There were no significant differences in the prevalence of any of
these cancers in relatives of the invasive and borderline probands. Cumulative
lifetime risk estimates did not differ between the relatives of the two groups
for any cancers. Age-at-onset of ovarian cancer did not differ between probands
with positive family histories of the five cancers and those with negative
histories. The inability to reject the null hypothesis of no differences in the
first-degree relatives of our two study groups might be from insufficient power
to detect small differences, given our sample size. CONCLUSION: These results
suggest that relatives of patients with invasive and borderline ovarian cancer
might share similar cancer risks and age-at-onset distributions.
PMID- 9764635
TI - BRCA1 gene mutations in women with papillary serous carcinoma of the peritoneum.
AB - OBJECTIVE: To compare BRCA1 mutations in papillary serous carcinoma of the
peritoneum and papillary serous ovarian carcinoma. METHODS: Germline DNA from 17
consecutive patients with peritoneal carcinoma was screened for mutations in the
BRCA1 gene using single-strand conformation polymorphism analysis. Shifted DNA
bands were sequenced. Patients with germline BRCA1 mutations were screened for
allelic loss in tumor DNA at the BRCA1 locus. RESULTS: Two of the 17 patients
(11%, 95% confidence interval 0.07, 0.37) exhibited the 185 delAG germline BRCA1
mutation described in the Ashkenazi Jewish population. The family history of one
patient was notable for a mother and five aunts with breast or ovarian cancer.
The other patient had a personal history of breast cancer. Both patients
exhibited allelic loss of the normal BRCA1 allele in their tumor. A third patient
was found to have a previously undescribed exon 11 single base pair substitution
at nucleotide 1239 (CAG to CAC) resulting in a missense mutation (Gln to His).
The patient had no family or personal history of breast or ovarian cancer, and
her tumor did not exhibit loss of heterozygosity. CONCLUSION: Germline BRCA1
mutations occur in papillary serous carcinoma of the peritoneum with a frequency
comparable to the BRCA1 mutation rate in ovarian cancer. Although the penetrance
is unknown, peritoneal carcinoma should be considered a malignancy expressed in
the familial breast ovarian cancer syndrome.
PMID- 9764636
TI - Evaluation of atypical and low-grade cervical cytology in private practice.
AB - OBJECTIVE: To evaluate the adequacy of cytology alone for diagnosis of grade of
cervical intraepithelial neoplasia (CIN) and to study performance of cytology,
human papillomavirus (HPV) testing, and colposcopy in the evaluation of cytologic
findings suggesting low-grade squamous intraepithelial lesions (SIL), or atypical
squamous (ASCUS) or atypical glandular (AGCUS) cells of undetermined
significance. METHODS: Standard gynecologic and cytologic evaluation and
colposcopic inspection as an additional screening approach were performed on
women with no prior hysterectomies screened in a private practice between January
1, 1993, and August 1, 1995. Among these 7651 women, 367 had ASCUS, AGCUS, or SIL
cytology or clinically or colposcopically visible cervical lesions. Sensitivity,
specificity, and relative risk of CIN in the 367 women were compared by
colposcopic, cytologic, histologic and virologic diagnoses. RESULTS: The
sensitivity of all non-negative Papanicolaou smears for CIN 2-3 and cancer was
92%, combined cytologic categories of high- and low-grade SIL were 59%, and high
grade SIL alone was 22%. Colposcopy was performed in all 367 patients, and
positive findings led to biopsies in 48%. Colposcopy of patients with ASCUS
increased detection of CIN 2-3 by 32% and CIN 1 by 48%. Cervical cytology was
false negative in 8% of patients with CIN 2-3 and in 14% of those with CIN 1.
These cases of CIN were detected by screening colposcopic inspection. High-risk
HPV DNA was positive in 41% of women with CIN 2-3, and in 25% of those with CIN
1. The positive predictive value of ASCUS cytology increased from 5% to 42% for
CIN 2-3 and from 30% to 85% for all grades of CIN in patients carrying high-risk
HPV DNA. Virologic studies did not add to an increase in the sensitivity for CIN
2-3 among women in the low- and high-grade SIL cytology groups. CONCLUSION:
Because of the limited sensitivity of the high-grade SIL cytologic category for
CIN 2-3, we recommend that all women with ASCUS, AGCUS, low- or high-grade SIL
cytology be recalled for colposcopy, with biopsy only when indicated by
colposcopic findings.
PMID- 9764637
TI - Clinical and urodynamic predictors of delayed voiding after fascia lata
suburethral sling.
AB - OBJECTIVE: To determine the time to resumption of normal voiding after a fascia
lata sling and whether any clinical, operative, or urodynamic variables predict
it. METHODS: Between January 1993 and September 1996, 62 women underwent fascia
lata suburethral sling operations for intrinsic sphincter deficiency or recurrent
stress incontinence. The demographic, operative, and urodynamic data of 61 of
these patients were analyzed. RESULTS: The mean number of days to resumption of
normal voiding was ten. Three patients (5%) developed permanent retention.
Patients 65 years and older were more likely than younger patients to have
prolonged catheterization (16 versus 7 days, P=.008). Women who had additional
procedures voided at a mean of 15 days compared to nine days for those having
slings only (P=.029). A preoperative urine flow rate less than 20 mL/sec was
associated with late voiding. There was no significant relationship between
preoperative voiding mechanism and voiding time. CONCLUSION: Resumption of normal
voiding occurred earlier than reported by others. Age over 65 years, additional
surgical procedures, and low peak flow rates were risk factors for delayed
voiding. Time to normal voiding was independent of the preoperative voiding
mechanism.
PMID- 9764638
TI - The effects of birth on urinary continence mechanisms and other pelvic-floor
characteristics.
AB - OBJECTIVE: To determine the effects of delivery on bladder and anorectal
functions. METHODS: One hundred forty-nine nulliparas were studied once during
pregnancy and again about 9 weeks after delivery by means of questionnaire,
clinical examination, perineal sonography, urethral pressure profiles, and
recording of intravaginal and intra-anal pressures during pelvic-floor
contraction. RESULTS: Stress urinary incontinence was present in 46 patients
(31%) during pregnancy and persisted in ten of them after delivery. After vaginal
delivery, urinary and fecal incontinence were present in 36% and 4% of forceps
delivered women, respectively, and in 21% and 5.5% of spontaneously delivered
women. Bladder neck mobility was increased significantly after all vaginal
births, whereas bladder neck position at rest was lowered only in forceps
delivered women. Functional urethral length was decreased in the supine and
standing positions after spontaneous and forceps deliveries. Otherwise, indices
of urethral sphincter function were unchanged or improved after vaginal delivery.
A significant decrease in intravaginal pressure and in intra-anal pressure was
observed in all vaginally delivered women. The intra-anal pressure decrease
correlated significantly with infant weight (r=0.24, P=.01). Women who underwent
cesarean had no specific complaints and only slight modifications of these
measurements. CONCLUSION: After spontaneous and instrumental deliveries, 21% and
34% of women complained of stress urinary incontinence and 5.5% and 4% reported
fecal incontinence, respectively. Substantial bladder neck hypermobility was
present together with diminished functional urethral length and intravaginal and
intra-anal pressures. Only 22% of patients with stress urinary incontinence
during pregnancy had such incontinence after delivery.
PMID- 9764639
TI - Extraperitoneal laparoscopic colposuspension: short-term cure rate,
complications, and duration of hospital stay in comparison with Burch
colposuspension.
AB - OBJECTIVE: To compare duration of surgery, length of hospital stay,
complications, and short-term cure rate of extraperitoneal laparoscopic
colposuspension with that of Burch colposuspension. METHODS: We retrospectively
reviewed 157 consecutive cases of extraperitoneal laparoscopic (n=70) or Burch
colposuspension (n=87) performed between January 1, 1995, and June 30, 1997. Cure
rate was assessed by history, physical examination, and questionnaire. Patients
not requiring the use of pads were considered continent. Cure rates were compared
in the entire group, whereas complications, duration of surgery, and length of
stay were compared only in subgroups undergoing colposuspension alone. Results
were analyzed statistically. RESULTS: The mean times to follow-up were 12.9
months (laparoscopic group) and 16.3 months (Burch group). At last follow-up, 64
of 70 (91.4%) of the laparoscopic and 80 of 87 (92%) of the Burch colposuspension
group were continent. In patients who underwent colposuspension alone, results
were as follows for those who underwent laparoscopic (19) and Burch (21)
procedures, respectively: average duration of surgery, 49.2 compared with 62.6
minutes (P < .03); average hospital stay, 14 hours compared with 2.7 days (P <
.001); average postoperative disability period, 1.6 weeks compared with 4.7 weeks
(P < .001); incidence of complications, 15.8% compared with 33.3% (P=.170).
CONCLUSION: Extraperitoneal laparoscopic colposuspension, compared with Burch
colposuspension, resulted in similar short-term cure rates and complications,
shorter duration of surgery, hospital stay, and convalescence. It is a feasible
option in treatment of stress urinary incontinence when laparotomy is not
required.
PMID- 9764640
TI - The "remote control" laparoscopic bag: a simple technique to remove intra
abdominal specimens.
AB - BACKGROUND: To facilitate extraction and avoid intra-abdominal spillage during
laparoscopic removal of adnexal masses, various designs and sizes of endopouches
(bags) have been used. We describe a simple technique using a special
laparoscopic bag that requires no additional instruments to hold, open, or close
the bag. TECHNIQUE: The laparoscopic bag can be prepared from the sterile
wrapping of disposable surgical items (eg, suction tubing) and two long sutures.
The bag is introduced through the cannula of the laparoscope and is unfurled. By
manipulation of the two long sutures threaded through the neck of the bag, the
surgeon can easily open and close it. EXPERIENCE: We have performed this
procedure "in vitro" on many occasions to ensure that the drawstring technique
works. The laparoscopic bag has been used successfully in three patients
undergoing oophorectomy and salpingo-oophorectomy. Our experience shows that this
type of laparoscopic bag is easy to use and safe, reduces operative time, and is
cost effective. Because the bag can be large, operating inside the bag is also
possible. CONCLUSION: Our drawstring design allows easy manipulation of a
laparoscopic bag to facilitate its opening and closure.
PMID- 9764641
TI - New concepts in the treatment of uterine leiomyomas.
AB - Uterine leiomyomas are a common clinical occurrence for gynecologists. The
current approach to treating these neoplasms is shaped by classic surgical
principles and the knowledge that these tumors are responsive to the gonadal
steroids estrogen and progesterone. As knowledge of leiomyomas advances through
the techniques of molecular biology and molecular genetics, new concepts are
developed that go beyond just myomas as steroid-responsive tumors. Understanding
the molecular events involved in the transformation of a normal myometrial cell
into a neoplastic cell and the subsequent growth of these leiomyoma cells will be
important in determining the pathogenesis of these tumors and providing new
targets for treatment. Knowing the role of peptide growth factors, including
basic fibroblast growth factor and transforming growth factor-beta, in the
pathogenesis of leiomyoma-related symptoms might lead to new treatments targeting
these molecules or their receptors. As the effects of genes, including HMGIC and
HMGI(Y), are determined; new treatments to prevent leiomyoma formation or growth
may be developed. As we gain understanding of the molecular events that cause
benign gynecologic conditions such as leiomyomas, safer and more effective
treatments might be found as we enter the 21st century.
PMID- 9764642
TI - Motivation and reward factors that affect private physician involvement in an
obstetrics and gynecology clerkship.
AB - OBJECTIVE: The Department of Obstetrics, Gynecology and Reproductive Biology in
the College of Human Medicine at Michigan State University has 163 private
practice obstetricians and gynecologists teaching clerkship students, on a
volunteer basis, in six Michigan cities. The department wanted to learn what
motivates their involvement in the department's required clerkship, to determine
their attitudes toward private office teaching, and to determine what incentives
are important to them in their role as educators. METHODS: The department
developed a questionnaire that was mailed to the obstetricians and gynecologists
involved in its required obstetrics and gynecology clerkship. The response rate
was 68% (111 of 163). RESULTS: Respondents indicated personal and professional
motivations transcend financial considerations. Almost 60% of respondents
reported at least a moderate interest in teaching in their private offices in
spite of perceived negative consequences, such as adverse impact on patient flow.
The incentives in which private practitioners were primarily interested included
seminars or meetings that would enhance their teaching skills or educational
contribution; discounts on computers, athletic and cultural events, and books;
and university support in producing educational materials. CONCLUSION:
Departments using private practitioners in medical education need to nurture the
relationship continually with their volunteer faculty. Faculty development aimed
at assisting private practitioners with their teaching role in the ambulatory
care setting might be extremely worthwhile. Financial remuneration may not be key
to attracting and retaining volunteer faculty. The implications of pay
arrangements for volunteer faculty should be considered carefully before
implementation.
PMID- 9764643
TI - Quantifying faculty teaching time in a department of obstetrics and gynecology.
AB - OBJECTIVE: The goal of this project was to develop a reproducible system that
measures quantity and quality of teaching in unduplicated hours, such that
comparisons of teaching activities could be drawn within and across departments.
Such a system could be used for allocating teaching monies and for assessing
teaching as part of the promotion and tenure process. METHODS: Various teaching
activities, including time spent in clinic, rounds, and doing procedures, were
enumerated. The faculty were surveyed about their opinions on the proportion of
clinical time spent in teaching. The literature also was reviewed. RESULTS: Based
on analysis of the faculty survey and the literature, a series of calculations
were developed to divide clinical time among resident teaching, medical student
teaching, and patient care. The only input needed was total time spent in the
various clinical activities, time spent in didactic activities, and the resident
procedure database. CONCLUSION: This article describes a simple and fair database
system to calculate time spent teaching from activities such as clinic, ward
rounds, labor and delivery, and surgery. The teaching portfolio database
calculates teaching as a proportion of the faculty member's total activities. The
end product is a report that provides a reproducible yearly summary of faculty
teaching time per activity and per type of learner.
PMID- 9764644
TI - Preterm contractions in community settings: I. Treatment of preterm contractions.
PMID- 9764645
TI - Necrotizing genital ulcerations in a premenarcheal female with mononucleosis.
AB - BACKGROUND: Two cases of genital ulcerations caused by Epstein-Barr virus have
been reported previously, one in a sexually active 23-year-old and another in a
14-year-old practicing cunnilingus. CASE: We report a case of Epstein-Barr virus
genital ulcerations in a premenarcheal virgin. Her systemic symptoms were
atypical for mononucleosis. Necrotizing genital ulcerations preceded pharyngitis
and oral lesions. Cervical adenopathy, fever, and splenomegaly never developed
despite serologic evidence of acute mononucleosis. CONCLUSION: Genital
ulcerations can be the initial manifestation of Epstein-Barr virus in adolescents
who are neither sexually active nor immunocompromised.
PMID- 9764647
TI - Thrombosis of the pelvic veins associated with a large myomatous uterus.
AB - BACKGROUND: Deep vein thrombosis is a rare indication for hysterectomy. CASE: A
45-year-old woman presented with a myomatous uterus of 20 gestational weeks' size
that was compressing the pelvic veins directly and causing thrombosis. After
preparation of the patient with anticoagulants and installation of an umbrella
device in the inferior vena cava, we performed an uneventful abdominal
hysterectomy. CONCLUSION: Pelvic deep vein thrombosis is a rarely reported
complication of myomatous uterus. It can be managed successfully by
anticoagulants, placement of an umbrella device in the inferior vena cava, and
hysterectomy, as in our case.
PMID- 9764646
TI - Chronic vaginal candidiasis responsive to biotin therapy in a carrier of
biotinidase deficiency.
AB - BACKGROUND: Many patients experience recurrent or persistent episodes of vaginal
candidiasis. Some of these women might be carriers of an inborn error of biotin
metabolism (either biotinidase deficiency or holocarboxylase synthetase
activity). These women might benefit from administration of pharmacologic amounts
of biotin. CASE: A 38-year-old gravida 2, para 2 carrier of biotinidase
deficiency presented with a 14-month history of persistent vaginal candidiasis,
despite appropriate therapy. After 3 months of pharmacologic doses of biotin, her
symptoms resolved completely. CONCLUSION: Given that 1 in every 123 individuals
is predicted to be a carrier of biotinidase deficiency, there might be other
women with chronic vaginal candidiasis who will respond to biotin administration.
PMID- 9764648
TI - Hydropic degenerating leiomyoma presenting as pseudo-Meigs syndrome with elevated
CA 125.
AB - BACKGROUND: Leiomyomas rarely cause pseudo-Meigs syndrome. Increased levels of CA
125 often are associated with some types of malignancy. No reported case of
pseudo-Meigs syndrome presenting with hydropic degeneration of uterine leiomyoma
and an elevated CA 125 level could be found on a MEDLINE search. CASE: A 46-year
old woman presented with a pleural effusion and a pelvic mass measuring 30 x 18
cm. Preoperative evaluation was remarkable for a CA 125 level of 254 U/mL. At
laparotomy, the diagnosis was a benign leiomyoma with focal hyaline and extensive
hydropic degeneration. Her pleural effusion resolved completely by 4 months
postoperatively. CONCLUSION: Pseudo-Meigs syndrome can present with an elevated
CA 125 level.
PMID- 9764649
TI - Suburethral abscess: a complication of periurethral collagen injection therapy.
AB - BACKGROUND: Urinary tract infection after collagen injection is well documented.
Other adverse reactions are rare. CASES: Three women experienced suburethral
abscess after repeat periurethral injections. All patients received local skin
preparation and postprocedural antibiotics. Symptoms failed to resolve with
antibiotics. The first two patients presented after 5 weeks and 10 days with
irritative voiding symptoms and a tender suburethral swelling. The first patient
was treated with excision. Spontaneous rupture into the urethra occurred with the
second. The third woman presented with acute urinary retention at 102 days. A
large suburethral mass was drained successfully in the office. CONCLUSION:
Suburethral abscess may be a delayed complication of periurethral collagen
injections, not preventable by postprocedural antibiotics. Drainage is required.
PMID- 9764650
TI - Hemochromatosis and male infertility.
AB - BACKGROUND: The clinical association of hemochromatosis and infertility is rare.
Hemochromatosis may affect fertility through a variety of mechanisms. CASE: A 44
year-old man and his 36-year-old wife presented with primary infertility of 7
years' duration. The husband was diagnosed as having idiopathic hemochromatosis,
abnormal glucose tolerance, and hypogonadism accompanied by impotence, retrograde
ejaculation, and azoospermia. Treatment consisted of phlebotomies followed by
gonadotropins, which corrected retrograde ejaculation and improved semen
characteristics. Concomitant pelvic factors in the woman were corrected
endoscopically. After failure of pregnancy with ovulation stimulation and
intrauterine inseminations, a singleton pregnancy was achieved by in vitro
fertilization, augmented with intracytoplasmic sperm injection. CONCLUSION: This
case underscores the need to consider advanced reproductive technologies after
the failure of specific, first-line therapeutic options in infertile couples.
PMID- 9764651
TI - Dysgerminoma with syncytiotrophoblastic giant cells arising from 46,XX pure
gonadal dysgenesis.
AB - BACKGROUND: Dysgerminoma with syncytiotrophblastic giant cells is a rare ovarian
tumor. Only ten cases of this tumor have been reported, and all tumors developed
in normal ovaries. This report presents a case of dysgerminoma with
syncytiotrophoblastic giant cells arising in a patient with 46,XX pure gonadal
dysgenesis. CASE: An 18-year-old phenotypic female of normal height without
somatic anomalies with nonfunctional ovaries underwent a bilateral gonadectomy
for a right ovarian tumor and left streak gonad. The tumor revealed a
dysgerminoma containing scattered syncytiotrophoblastic giant cells. Her serum
hCG was elevated, and hCG was demonstrated within syncytiotrophoblastic giant
cells immunohistochemically. The clinical diagnosis was stage Ia dysgerminoma
with syncytiotrophoblastic giant cells. Her karyotype was 46,XX and the sex
determining region Y gene was not detected in tumor DNA by polymerase chain
reaction analysis. CONCLUSION: This rare gonadal tumor may arise from dysgenetic
gonads in addition to gonadoblastoma and pure dysgerminoma. It is an example of
tumorgenesis in pure gonadal dysgenesis with no identifiable Y chromosome
component.
PMID- 9764652
TI - Fertility options for patients with stages IA2 and IB cervical cancer:
presentation of two cases and discussion of technical and ethical issues.
AB - BACKGROUND: Ten percent to 15% of women diagnosed with cervical cancer are in
their childbearing years. Traditional therapy for stage IA2 and IB lesions,
radical hysterectomy, negates future fertility potential. Assisted reproductive
technology might offer these women fertility options. CASES: Two cases of young
nulliparous women with stage IA2 cervical cancer, who underwent ovarian
stimulation and oocyte retrieval followed by radical hysterectomy, were presented
to illustrate the technical difficulties of oocyte stimulation and retrieval in
the setting of cervical carcinoma. CONCLUSION: Many issues should be considered
when counseling a woman with early-stage cervical cancer about future fertility.
These include ethical issues of embryo freezing and gestational surrogacy and
practical issues of ovarian preservation and transposition. No current guidelines
exist to identify appropriate candidates for assisted reproductive technology in
this setting.
PMID- 9764653
TI - Psammocarcinoma with an aggressive course.
AB - BACKGROUND: Psammocarcinoma is an unusual variant of serous cystadenocarcinoma
characterized by heavy deposits of psammoma bodies. This disease has been
suggested to be similar to carcinomas of low malignant potential in its indolent
clinical course. We present this case report of an aggressive course of this
disease to alert others that psammocarcinoma may not always follow a benign
course. CASE: A 66-year-old woman underwent staging laparotomy for bilateral
ovarian cystadenofibromata with rare foci of borderline serous tumors and several
small bowel peritoneal surface nodules showing infiltrating psammocarcinoma. She
was not recommended for adjuvant therapy because of the previously reported
indolent course of this disease. Eighteen months later she represented with small
bowel obstruction and underwent an exploratory laparotomy that demonstrated
diffuse recurrence of the psammocarcinoma. CONCLUSION: Psammocarcinoma may have a
more aggressive course than has been suggested. Patients with this disease should
have optimal tumor debulking. There may be a role for adjuvant therapy in its
treatment.
PMID- 9764654
TI - Encouraging response of an advanced steroid-cell tumor to GnRH agonist therapy.
AB - BACKGROUND: Chemotherapy for steroid tumors of unspecified type has met with
limited success and the overall prognosis has been poor. CASE: A patient with a
virilizing steroid tumor, otherwise unspecified, with demonstrated progressive
disease after surgical debulking. Treatment with multiagent chemotherapy failed,
but the patient subsequently had a robust response to GnRH agonist therapy.
CONCLUSION: GnRH analogue treatment should be considered prior to cytotoxic
chemotherapy in cases of steroid tumor, not otherwise specified.
PMID- 9764655
TI - Aborted leiomyosarcoma after treatment with leuprolide acetate.
AB - BACKGROUND: Leuprolide acetate has been used to decrease uterine size and shrink
leiomyomata. In carefully selected patients, its treatment benefits are well
recognized. However, if leuprolide acetate is inadvertently given to a patient
with an unsuspected leiomyosarcoma, complications may occur. CASE: A patient
presumed to have leiomyomata was treated with monthly injections of leuprolide
acetate. In the third month of treatment, unusual manifestations, including
increased bleeding, aborting mass, urinary retention, and severe pain, occurred
suggesting a possible malignancy and requiring immediate operation. CONCLUSION:
The use of leuprolide acetate can delay the diagnosis and treatment of
leiomyosarcoma and thus may increase the risk of morbidity and affect the
treatment outcome of patients with leiomyosarcoma. The histologic changes
ascribed to leuprolide acetate treatment in leiomyomata also were seen in this
leiomyosarcoma.
PMID- 9764656
TI - Metastatic uterine leiomyosarcoma presenting as a primary sarcoma of the parotid
gland.
AB - BACKGROUND: Leiomyosarcoma of the uterus has a high metastatic potential to
distant sites due to its tendency for hematogenous spread. CASE: A 49-year-old
woman presented with an enlarging parotid mass, diagnosed originally as a primary
fibrosarcoma. Six years later, she developed pulmonary metastases and heavy,
abnormal uterine bleeding. At hysterectomy, a uterine leiomyosarcoma, identical
morphologically to the previous lesions, was identified. All tumors showed
similar immunohistochemical staining, suggesting the metastatic nature of the
original parotid tumor. CONCLUSION: This rare case of uterine leiomyosarcoma,
presenting as a primary parotid sarcoma, underscores the importance of
considering the possibility of a uterine primary tumor when a sarcoma arises in
an organ in which these tumors are unusual.
PMID- 9764657
TI - Conservative management of uterine rhabdomyosarcoma.
AB - BACKGROUND: Rhabdomyosarcomas are rare, malignant tumors derived from primitive
myogenic precursors and are the most common soft tissue neoplasms in children and
adolescents. We used primary chemotherapy and subsequent removal of the residual
polypoid mass to treat an adolescent female with uterine rhabdomyosarcoma. CASE:
A 15-year-old white adolescent who presented with a polypoid uterine
rhabdomyosarcoma was treated with vincristine, etopside, and ifosfamide, after
which the residual polypoid mass was removed. CONCLUSION: Treating adolescent
females with a polypoid uterine rhabdomyosarcoma with primary chemotherapy
followed by removal of the residual mass preserves reproductive function and
should be considered.
PMID- 9764658
TI - Catamenial fevers associated with a uterine smooth muscle tumor of undetermined
malignant potential.
AB - BACKGROUND: Pyrexia associated with solid and hematogenous neoplasms are a well
recognized clinical condition. Menstrually related (catamenial) fevers have not
been reported previously. CASE: A 52-year-old woman with a history of stage I
breast cancer on adjuvant tamoxifen citrate presented with recurrent fevers
associated with menses. An extensive evaluation of possible causes, including
recurrent breast cancer and infectious, collagen-vascular, and drug-related
sources, initially was unrevealing. A gynecologic evaluation identified a uterine
tumor, which appeared to be a cellular leiomyoma on hysteroscopic biopsy. The
catamenial fevers resolved immediately after hysterectomy. A uterine smooth
muscle tumor of undetermined malignant potential was identified on pathology.
CONCLUSION: Smooth muscle tumors of the myometria are a rare cause of menstrual
fevers.
PMID- 9764659
TI - Coagulopathy secondary to vitamin K deficiency in hyperemesis gravidarum.
AB - BACKGROUND: Hyperemesis gravidarum is a condition of pregnancy characterized by
excessive nausea and vomiting, which can be associated with malnutrition. Vitamin
K deficiency is a known complication of malnutrition as well as a known cause of
coagulopathy. To date, there is no reported case in the literature of vitamin K
deficiency in hyperemesis gravidarum. CASE: A woman at 15 weeks' gestation
presented with hyperemesis gravidarum complicated by an episode of severe
epistaxis. Investigation revealed coagulopathy secondary to vitamin K deficiency.
The coagulopathy resolved after vitamin K replacement, with complete correction
of all clotting factors. CONCLUSION: Vitamin K deficiency and coagulopathy should
be considered in women with hyperemesis gravidarum who present with a bleeding
diathesis. Prophylactic vitamin K replacement should be considered in cases in
which hyperemesis is severe and protracted.
PMID- 9764660
TI - Burkitt lymphoma in pregnancy.
AB - BACKGROUND: Burkitt lymphoma during pregnancy is a rare event, and outcomes have
been poor. However, few patients were treated by current standards, with nearly
half receiving single-agent cyclophosphamide or no chemotherapy. CASE: A patient
with Burkitt lymphoma presenting at 11 6/7 weeks' gestation was treated with
surgical resection of all visible disease and cytotoxic combination chemotherapy.
The patient was disease free at 1 year after diagnosis. CONCLUSION: When Burkitt
lymphoma is encountered in pregnancy, immediate cytotoxic combination
chemotherapy is indicated.
PMID- 9764661
TI - Acute intentional iron overdose in pregnancy.
AB - BACKGROUND: Although iron is the second most common overdose agent in pregnancy,
the obstetric literature does not reflect current management of this emergency.
CASE: A 27-year-old woman, para 0-3-4-3, at 27 weeks' gestation ingested 24 mg/kg
of elemental iron in a suicide attempt. Therapy with crystalloid hydration,
gastric lavage, and intravenous deferoxamine chelation treated the overdose
without maternal or fetal complications. CONCLUSION: Pregnancy should not alter
therapy for acute iron overdose. Deferoxamine administered in the third trimester
is not associated with perinatal complications and is potentially life saving.
PMID- 9764662
TI - Successful pregnancy outcome after complicated varicella pneumonia.
AB - BACKGROUND: Maternal and fetal morbidity and mortality associated with varicella
pneumonia in the peripartum period are increased further with multiple
complications. CASE: The patient had varicella pneumonitis acquired at 32 weeks'
gestation and complicated by bacterial superinfection, adult respiratory distress
syndrome, endotoxin shock, and bronchiolitis obliterans organizing pneumonia.
CONCLUSION: Aggressive, timely management of respiratory failure, control of
infection, correction of endotoxin shock, treatment of biopsy-proven
bronchiolitis obliterans organizing pneumonia, and obstetric intervention for
fetal compromise produced a good outcome for mother and infant.
PMID- 9764663
TI - Isolated pulmonary cryptococcosis in pregnancy.
AB - BACKGROUND: Isolated pulmonary cryptococcosis in an immunocompetent parturient
host is a rare event. Little is known about this condition, its prognosis, and
its treatment in the immunocompetent pregnant woman. CASE: A 28-year-old woman,
para 3, was diagnosed with isolated pulmonary cryptococcosis postpartum. She had
delivered a healthy neonate at term who revealed no clinical features compatible
with maternal-fetal transmission. The woman was monitored closely throughout the
course of her disease and radiogic, clinical, and serologic resolution was
achieved after treatment with fluconazole. CONCLUSION: Patients with pulmonary
cryptococcosis present with clinical pictures similar to other well-known
diseases such as septic pulmonary emboli or choriocarcinoma. Treatment with
triazole antifungal therapy yielded favorable results in our patient with this
rare condition.
PMID- 9764664
TI - New sonographic findings in a fetus with an interstitial deletion in the long arm
of chromosome 14.
AB - BACKGROUND: Interstitial deletions of 14q in which band 14q31 is deleted are
uncommon. Malformations such as atrial septal defect, horseshoe kidney, and
cryptochidism have been reported. CASE: We evaluated sonographically the fetus of
a 22-year-old woman between 16 and 20 weeks' gestation. This imaging showed
marked dilation of the bladder with mild bilateral hydronephrosis and bilateral
dilation of the lateral ventricles. In an amniotic fluid specimen obtained at 17
weeks, chromosomal analysis showed an interstitial deletion of chromosome 14
including band 14q31, designated 46,XY,del(14)(q24.3q32.1). CONCLUSION: This
first-reported fetal case of interstitial deletion in chromosome 14 including
band 14q31 showed anomalies not seen in the reported postnatal cases.
PMID- 9764665
TI - Unconjugated estriol as an indication for prenatal diagnosis of steroid sulfatase
deficiency by in situ hybridization.
AB - BACKGROUND: Undetectable or very low unconjugated estriol (E3) levels in routine
maternal serum screening are associated with steroid sulfatase deficiency,
miscarriages, and anencephaly. CASES: Fluorescence in situ hybridization
techniques were used in the diagnosis of steroid sulfatase deficiency prenatally
in three cases with low or undetectable unconjugated E3 levels. Results showed a
male fetus with a deleted steroid sulfatase region, but intact Kallmann syndrome
region in all three cases. One mother was studied by fluorescence in situ
hybridization and showed a similar deletion for steroid sulfatase gene in one
copy of X chromosome (carrier). CONCLUSION: Women with undetectable or very low
levels of estriol on serum screening should be counseled regarding steroid
sulfatase deficiency with evaluation by fluorescence in situ hybridization.
PMID- 9764666
TI - A new therapeutic approach to the fetus with congenital complete heart block:
preemptive, targeted therapy with dexamethasone.
AB - BACKGROUND: Therapy of established congenital complete heart block in the fetus
has resulted in improved survival but persistence of heart block. This exposes
the infant to the morbidity of heart block, including the risk of sudden death
and pacemaker implantation. CASE: A 35-year-old gravida 2, para 1, with Sjogren
syndrome and a previous pregnancy complicated by congenital complete heart block
presented during her second pregnancy. Intensive fetal monitoring with
echocardiography was employed. Early evidence of myocardial dysfunction and
dysrhythmia was found, dexamethasone therapy was initiated, and the dysfunction
and dysrhythmia resolved. The pregnancy went to term without further
complication. CONCLUSION: This represents a new and successful strategy to
identify very early signs of myocardial disease in a fetus at high risk of
congenital complete heart block, enabling targeted, preemptive therapy.
PMID- 9764667
TI - Magnesium sulfate, maternal hypothermia, and fetal bradycardia with loss of heart
rate variability.
AB - BACKGROUND: Fetal bradycardia and decreased heart rate variability can indicate a
nonreassuring fetal status. However, there can be iatrogenic, physiologic, or
pathologic causes. CASE: A patient in premature labor received toxic levels of
magnesium sulfate for tocolysis. Elevated maternal serum magnesium levels
correlated inversely with maternal temperature and both fetal heart rate and
fetal heart rate variability. There was also a relative decrease of the maternal
heart rate from baseline. When the magnesium levels returned to normal, these
vital signs returned to normal. CONCLUSION: Magnesium sulfate therapy can result
in maternal hypothermia and a decrease in fetal heart rate and heart rate
variability. Maternal hypothermia might be the cause of fetal bradycardia. A
direct action of magnesium on the fetal heart might be the cause of heart rate
variability.
PMID- 9764668
TI - Hysterotomy facilitation of the vaginal delivery of the posterior arm in a case
of severe shoulder dystocia.
AB - BACKGROUND: Shoulder dystocia is an obstetric emergency that can be resolved
usually with one or a series of maneuvers performed vaginally. On rare occasions
these maneuvers may fail, and the obstetrician must employ less familiar
techniques to achieve delivery. CASE: A 30-year-old, gravida 6, developed a
severe shoulder dystocia while delivering a 5970 g infant. Classical vaginal
maneuvers failed due to the severity of the impaction. After general anesthesia
was induced, additional maneuvers such as cephalic replacement and transabdominal
rotation also failed. The dystocia was resolved ultimately by a transabdominally
facilitated vaginal posterior arm delivery followed by transabdominal shoulder
rotation and vaginal extraction. CONCLUSION: In catastrophic cases of shoulder
dystocia, transabdominal performance or facilitation of traditional vaginal
maneuvers may lead to resolution.
PMID- 9764669
TI - Cesarean delivery of twins during maternal cardiopulmonary arrest.
AB - BACKGROUND: In modern times, maternal death is rare. Timely cesarean delivery in
the setting of maternal cardiopulmonary arrest may save both the infant and the
mother. CASE: A 36-year-old white woman with a twin pregnancy suffered
cardiopulmonary arrest at 28 weeks' gestation. Advanced cardiopulmonary
resuscitative measures were unsuccessful, and the twins were delivered by
cesarean at the bedside. Immediately after delivery, a maternal pulse was noted;
both the mother and her infants are alive 15 months later. CONCLUSION: Relieving
vena caval occlusion by perimortem cesarean delivery in a term gravida allows
chest compressions to provide sufficient cardiac output in the unfortunate event
of maternal cardiopulmonary arrest. When delivery occurs within 5 minutes of
maternal insult, the neonatal outcome is favorable.
PMID- 9764670
TI - Postpartum renal failure: a complex case with probable coexistence of hemolysis,
elevated liver enzymes, low platelet count, and hemolytic uremic syndrome.
AB - BACKGROUND: Postpartum renal failure in previously healthy subjects is associated
most often with preeclampsia and/or hypertension; hemolysis, elevated liver
enzymes, low platelets (HELLP) syndrome, hemolytic uremic syndrome; or thrombotic
thrombocytopenic purpura. Transient oliguria associated with preeclampsia is
common, but renal failure is rare. Coexistence of HELLP and hemolytic uremic
syndromes has been suggested, but histopathologic documentation of this
combination has been scarce. CASE: A 30-year-old primigravida with severe
preeclampsia at 35 weeks and 3 days' gestation presented with the development of
HELLP syndrome and renal failure postpartum. Histopathologic lesions
characteristic of hemolytic uremic syndrome were present in the kidney.
CONCLUSION: Probable overlapping of HELLP and hemolytic uremic syndromes in
pregnancy or postpartum should be taken into consideration when treating patients
with these syndromes and associated complications, such as renal failure.
PMID- 9764671
TI - Hypereosinophilic syndrome in a trisomy 21 fetus.
AB - BACKGROUND: Hypereosinophilic syndrome is characterized by peripheral blood
eosinophilia and multiple organ system involvement. Only one case in a newborn
has been reported. CASE: Fetal sonography performed on a 33-year-old woman at 35
weeks' gestation showed pericardial effusion and cardiomegaly. The infant was
delivered by cesarean at 35 weeks' gestation because of a worsening of the
pericardial effusion. Hematologic studies revealed unexplained hypereosinophilia,
and the pericardial fluid contained a large number of eosinophils. Chromosomal
analysis revealed trisomy 21. The hypereosinophilia, pericardial effusion, and
cardiomegaly all resolved after 8 weeks of steroid therapy. CONCLUSION:
Hypereosinophilic syndrome caused pericardial effusion and cardiomegaly in a
fetus with trisomy 21.
PMID- 9764672
TI - Postmortem DNA diagnosis of factor V Leiden in a neonate with systemic thrombosis
and probable antithrombin deficiency.
AB - BACKGROUND: Spontaneous neonatal thrombosis due to heritable gene defects has
been reported in the past. A recently discovered defect, the factor V Leiden
mutation, is the most frequent inherited risk factor for venous thrombosis. CASE:
Factor V Leiden was diagnosed postmortem in a neonate who died from complications
of vena caval and aortic thrombosis. Investigation into the family history
revealed that the father had a record of multiple thromboses, and blood testing
demonstrated that the father had antithrombin deficiency and the mother was
heterozygous for factor V Leiden. Although we were unable to demonstrate directly
the presence of antithrombin deficiency in the infant, we propose that a
combination of the two inherited disorders was likely the cause of fatal neonatal
thrombosis. CONCLUSION: The present report highlights the importance of a
complete prenatal genetic analysis, including factor V Leiden testing and
antithrombin measurement in families with a history of thrombotic disorders.
PMID- 9764673
TI - Etretinate: therapy for plasma cell vulvitis.
PMID- 9764674
TI - Deep vein thrombosis in patients with large uterine myomata.
PMID- 9764675
TI - A carcinoid tumor of the broad ligament.
PMID- 9764676
TI - Abdominal tuberculosis mimicking metastatic ovarian carcinoma.
PMID- 9764677
TI - Delayed retained products of conception after second-trimester abortion.
PMID- 9764679
TI - Transfusion issues in a gravida with sickle cell disease.
PMID- 9764678
TI - Successful pregnancy in an adolescent with perinatally acquired human
immunodeficiency virus.
PMID- 9764680
TI - Marfan syndrome, aortic dilatation, and pregnancy.
PMID- 9764681
TI - Fetal triploidy: a unique cause of the stuck twin sign.
PMID- 9764682
TI - Intrauterine Listeria infection of the nonpresenting twin.
PMID- 9764683
TI - Conjoined twins in a triplet pregnancy.
PMID- 9764684
TI - Breast engorgement and lactation associated with thyrotropin-releasing hormone
administration.
PMID- 9764685
TI - Resolution of fetal tachycardia and hydrops by a single adenosine administration.
PMID- 9764686
TI - Placental abruption and fetal death with airbag deployment in a motor vehicle
accident.
PMID- 9764687
TI - Surgical debridement of necrotizing endomyometritis after cesarean delivery.
PMID- 9764688
TI - Disseminated neonatal herpes infection.
PMID- 9764689
TI - Meta-analysis of estrogen therapy in the management of urogenital atrophy in
postmenopausal women: second report of the Hormones and Urogenital Therapy
Committee.
AB - OBJECTIVE: To evaluate the efficacy of estrogen therapy in the treatment of
postmenopausal women with symptoms and signs associated with urogenital atrophy,
by meta-analysis of available data. METHODS: We searched the literature (Excerpta
Medica, Biosis, MEDLINE, and hand search) for studies published between January
1969 and April 1995. Criteria for inclusion were English-language articles, peer
reviewed original publications, and urogenital atrophy assessed by at least one
of the following outcomes: patient symptoms, physician report, pH, or cytologic
change. Data had to allow comparison between treated and control groups in
controlled trials or an estimated change from baseline in uncontrolled series.
Meta-analytic methods were applied separately to controlled clinical trials and
uncontrolled studies. RESULTS: Of the 77 relevant articles reviewed, nine
contained ten randomized controlled trials. Meta-analysis of these using the
Stouffer method revealed a statistically significant benefit of estrogen therapy
for all outcomes studied. In 54 uncontrolled case series, the patient symptoms
were treated by 24 different treatment modalities. All routes of administration
appeared to be effective and maximum benefit was obtained between 1 and 3 months
after the start of treatment. As expected, the least systemic absorption of
estrogen was seen with estriol (administered orally or vaginally), then vaginal
estradiol as measured by pretherapy and posttherapy serum estradiol and estrone.
CONCLUSION: Estrogen is efficacious in the treatment of urogenital atrophy and
low-dose vaginal estradiol preparations are as effective as systemic estrogen
therapy in the treatment of urogenital atrophy in postmenopausal women.
PMID- 9764690
TI - Natural history of cervical squamous intraepithelial lesions: a meta-analysis.
AB - OBJECTIVE: To define the strengths and weaknesses of existing research on the
natural history of cervical squamous intraepithelial lesions (SIL) and to
estimate rates of progression and regression without treatment. DATA SOURCES:
Studies of women whose cervical smears showed squamous atypia or worse and who
were observed for a minimum of 6 months were identified by a search of MEDLINE
from 1966 to 1996, Current Contents, the Federal Research in Progress database,
and references of review articles and identified studies, and by experts in the
field. METHODS OF STUDY SELECTION: Fifteen of 81 studies were eligible for data
extraction. To be eligible, studies had to report a minimum of 6 months' follow
up without treatment; relate entry cytologic findings to outcomes; and report
entry cytologic findings so that the study population could be stratified into
categories of atypical cells of undetermined significance (ASCUS), low-grade SIL,
or high-grade SIL. Studies published before 1970 were excluded. TABULATION,
INTEGRATION, AND RESULTS: Eligible studies, representing 27,929 patients, were
stratified according to entry cytologic findings. The following rates of
progression to high-grade SIL at 24 months were found: ASCUS, 7.13% (95%
confidence interval [CI] 0.8%, 13.5%); low-grade SIL, 20.81% (6.08%, 35.55%); and
high-grade SIL, 23.37% (12.82%, 32.92%). The following rates of invasive cancer
at 24 months were found: ASCUS, 0.25% (0%, 2.25%); low-grade SIL, 0.15% (0%,
0.71%); and high-grade SIL, 1.44% (0%, 3.95%). The following rates of regression
to normal were found: ASCUS, 68.19% (57.51%, 78.86%); low-grade SIL, 47.39%
(35.92%, 58.86%); and high-grade SIL, 35.03% (16.57%, 53.49%). Study
heterogeneity was not explained by regression analysis of study level variables.
CONCLUSION: Our findings for borderline and low-grade abnormal cervical cytologic
results suggest a relatively low risk of invasive cervical cancer with
observation up to 24 months and support the clinical policy of early colposcopy
for high-grade lesions.
PMID- 9764691
TI - Safety and durability of single-layer, stentless, biliary-enteric anastomosis.
AB - Biliary-enteric anastomosis has long been associated with significant
complications of early bile leak, cholangitis, and late stricture formation, and
controversy exists regarding which operative technique best prevents these
problems. Biliary-enteric anastomosis was performed using a single-layer running
4-0 polyglactin (Vicryl) suture, without a transanastomotic stent, in 97 patients
by a single surgeon over a 17-year period. Indications for operation included
malignant obstruction (84.5%), benign stricture, choledocholithiasis, and
choledochal cyst. The most common operation performed was a
choledochoduodenostomy; the remaining operations were either Roux-en-Y
choledochojejunostomy, hepaticoduodenostomy, or Roux-en-Y hepaticojejunostomy.
Complications occurred in 14.1 per cent of patients; there was one perioperative
death. There was only one case of anastomotic leak (1%), which resolved
spontaneously within 1 week. Mean hospital stay was 8.7 days. The mean follow-up
was 13.1 months in all patients. Among patients with benign disorders of the
biliary tract, the mean follow-up was 21 months, during which time no patient
developed an anastomotic stricture. One patient experienced postoperative
cholangitis, although not as a result of anastomotic stricture. Biliary-enteric
anastomosis for both benign and malignant disorders can be safely performed using
a running, absorbable suture without a stent.
PMID- 9764692
TI - Prognosis and treatment of bile duct carcinoma.
AB - Bile duct carcinomas present a therapeutic challenge because of different
histologies, tumor locations, and resectabilities. The goal of our study was to
identify prognostic factors to better delineate therapeutic options. Forty
patients (30 males and 10 females) diagnosed with bile duct cancer, treated
between 1985 and 1996, at Kaiser Permanente Medical Center, Los Angeles were
retrospectively reviewed. Three prognostically significant variables were
identified: tumor histology, tumor location, and resection. Papillary histology
was the most significant determinant of long-term survival. Of six patients with
papillary adenocarcinoma, four patients (67%) underwent resection, with all four
achieving long-term survival. Lower-third lesions also demonstrated a survival
advantage. Four out of 12 (33%) lower-third tumors were resected, with a median
survival of 36 months. Irrespective of tumor histology or tumor location, tumor
resection always afforded longer survival times than did palliative treatments. A
prognostic classification system based on weighted values of significant
variables is presented that accurately predicted long-term survival. In
conclusion, bile duct tumors in general are incurable, except perhaps for a small
subset of patients with papillary adenocarcinoma. Papillary histology is the most
significant determinant of ultimate survival and cure. A multifunctional
prognostic classification system can be helpful for this perplexing disease.
PMID- 9764693
TI - Outcomes from nonemergent orthotopic liver transplantation: is postoperative care
becoming routine?
AB - The outcome of surgical intensive care unit (SICU) care after nonemergent
orthotopic liver transplantation (OLTX) was evaluated in 168 consecutive patients
over a 6-year period (1/90-12/95). Prospective data collected included age, first
and last SICU day Simplified Acute Physiology Score and Quantitative Therapeutic
Intervention System Score, SICU length of stay (LOS), and mortality. The patient
population was 61 per cent male and 39 per cent female, with ages ranging from 20
to 75 years. A total of four patients died in the SICU, for a mortality of 2.4
per cent. Over the study period, SICU LOS decreased by 21 per cent, from 3.9 +/-
0.7 to 3.1 +/- 0.3 days (P < 0.05). Although no difference in admission severity
of illness was observed over the study period, there was an increase in the
intensity of intervention performed on admission to the SICU. Over the study
period, there was no difference in severity of illness or intensity of
intervention upon discharge to floor care. The decreased SICU LOS did not
adversely affect patient mortality or severity of illness upon SICU discharge
during the 6-year period. With intensified SICU intervention, nonemergent
orthotopic liver transplantation patients can have a shorter SICU LOS without
adverse effects on outcome.
PMID- 9764694
TI - Gastric cancer: three decades of surgical management.
AB - Hospital records of all 277 patients who underwent surgery for gastric
adenocarcinoma at the University of California at Los Angeles Medical Center from
1970 through 1996 were reviewed. Patients were stratified into three groups
comprising 1970 to 1979, 1980 to 1989, and 1990 to 1996. The incidence of stage
IV disease decreased by 50 per cent over the course of the study (P < 0.001).
Lymph node involvement declined by 30 per cent (P < 0.01). Endoscopy displaced
contrast radiography as the primary diagnostic modality. Sensitivity of
endoscopic biopsy averaged 92 per cent. Twice as many patients were resected for
cure in the current decade compared with the 1970s (P < 0.001). Operative
mortality was less than 2.5 per cent for the entire period studied and has been
nil in the 1990s. Intraoperative blood loss and transfusion requirements also
decreased significantly each decade. Hospital stay was shortened by 41 per cent
and the length of postoperative stay in the intensive care unit decreased from a
median of 4 days to zero. Five-year survival improved significantly during the
study period, mirrored by an increase in survival for early cancers. We have
found an earlier presentation of gastric adenocarcinoma over the past 3 decades
that parallels an increased use of endoscopy and an improved sensitivity of
endoscopic biopsy. More patients are now resectable than in previous decades.
Survival after surgical treatment of gastric adenocarcinoma improved between 1970
and 1996, partially due to an increase in earlier stage lesions. Improved
survival is also demonstrable when only early stage cancers are considered.
PMID- 9764695
TI - Ultrasound characteristics of breast carcinoma.
AB - Recent advances in ultrasound technology, such as the use of high-frequency
linear transducers, color flow Doppler, and computer-enhanced imaging, have
improved the diagnostic utility of ultrasound. The following retrospective study
was performed to evaluate the efficacy of sonographic signs of malignancy and to
compare sonography to mammography in 157 patients with palpable, biopsy-proven
breast carcinomas. The mammogram reports and sonograms were all reviewed. The
grade of each mammogram was recorded using the American College of Radiology
mammogram grading scale. All sonograms were reviewed and assigned a score using
an adaptation of this scale. Of 157 lesions, 121 were read as suspicious or
probable malignancies on mammogram. Thirty-three lesions were read as benign or
normal on mammogram. Three patients did not receive mammograms. All 157 lesions
were read as either suspicious or probably malignant on ultrasound. Using the 16
described criteria, high-definition sonography complements mammography and
appears to be a sensitive modality in the evaluation of palpable biopsy-proven
breast malignancies. The diagnostic utility of ultrasound will likely be most
important in the evaluation of nonpalpable breast masses; however, a prospective
randomized trial will need to be performed.
PMID- 9764696
TI - Two decades of cervical esophagostomy: indications and outcomes.
AB - Diverting cervical esophagostomy is a surgical procedure generally reserved for
extremely ill patients as a life-saving maneuver. However, it is also a procedure
that is infrequently performed, such that most centers have limited experience
with the operation. To investigate the indications and outcomes of cervical
esophagostomy, we reviewed the use of this operation at UCLA Medical Center over
the last 20 years as employed for esophageal leaks. Eighteen patients underwent
this procedure for the following indications: leak with malignant
tracheoesophageal fistula (11%), anastomotic leak (44%), endoscopic injury (18%),
gunshot wound (5.5%), operative injury (11%), corrosive ingestion (11%), and
spontaneous rupture (5.5%). Overall mortality directly attributable to sepsis was
33 per cent. Of the surviving patients, 67 per cent later underwent
reconstruction. Seventy-two per cent of patients had end esophagostomies, and the
remainder had loop diversions. The primary indication for operation in these
patients was persistent sepsis after initial surgical management of esophageal
spillage into the mediastinum or neck. This series suggests that cervical
esophagostomy, when applied to the appropriate patient population, can decrease
mortality and allow subsequent alimentary reconstruction.
PMID- 9764697
TI - Accelerated recovery after coronary artery bypass surgery in patients with poor
left ventricular function: preliminary report.
AB - The success of "fast-track" accelerated recovery pathways in improving patient
outcomes after coronary artery bypass graft surgery (CABG) has prompted expanded
application. Although initially used only in routine cases, higher-risk cohorts
may also benefit from this collection of management techniques. Twenty-seven
consecutive patients with ejection fractions (EFs) less than or equal to 30 per
cent (group I) undergoing CABG requiring cardiopulmonary bypass were started on
our routine care path. The results of this effort were retrospectively compared
with 27 concurrent patients with an EF greater than or equal to 50 per cent
(group II) undergoing CABG at our institution. Outcome criteria included
postoperative extubation (by 6 hours), transfer from intensive care unit (in < or
= 24 hours), and hospital discharge on or before postoperative day 5. As
anticipated, group I patients deviated from pathway criteria more frequently than
did group II. However, despite severely compromised preoperative cardiac
function, 52 per cent of group I patients were extubated within the first 6 hours
postoperatively, 51 per cent were discharged from the intensive care unit on the
1st postoperative day, and 52 per cent were discharged from the hospital within
the first 5 postoperative days. Group II patients' values for these parameters
were 96, 96, and 70 per cent, respectively. No adverse effects could be
attributed to pathway expectations. The results of this preliminary study suggest
that accelerated care pathways may be safely applied to patients with severely
low EFs and deserve further study.
PMID- 9764698
TI - Molten metal burns: early treatment improves outcome.
AB - Molten metal burns have received relatively little attention in the surgical
literature. We performed a retrospective chart review of 150 patients who
sustained molten metal burns between 1972 and 1997. The injuries all occurred in
male foundry workers, most commonly from molten aluminum (60%). The typical
accident was that of a splatter spill, creating a full-thickness burn. The mean
burn size was 2.3 per cent of the body surface area (range, 0.25-25%). The lower
extremities were the most commonly injured areas (85%), yet 37 per cent of
patients had multiple sites burned. Patients were often initially treated
nonoperatively and then referred to a surgeon when the wound failed to heal.
Hospitalization was necessary in 89 patients at a mean of 16 days after the
injury, and 92 patients required an operation, most commonly excision of the
wound with skin grafting. The mean length of hospital stay was 11.2 days, and
mean absence from work was 72.6 days. Fifty-one patients treated by the burn
surgeon within 2 weeks of injury had a mean length of disability significantly
shorter than those referred late (53.5 vs. 83.4 days; P < 0.05). We believe that
an underestimation of the severity of these burns often leads to a delay in
correct therapy and extends disability.
PMID- 9764700
TI - Laparoscopic management of acute cholecystitis with subtotal cholecystectomy.
AB - Approximately 20 per cent of laparoscopic cholecystectomies performed for acute
cholecystitis require conversion to open cholecystectomy because of severe
inflammation. In a retrospective review of 125 consecutive patients undergoing
laparoscopic surgery for gallbladder disease from January 1995 through June 1997,
31 had acute cholecystitis. Eight patients underwent a subtotal cholecystectomy
because of severe inflammation. There were no conversions to open cholecystectomy
and no intraoperative complications. Selected patients were evaluated and treated
for common duct stones with preoperative endoscopy to avoid intraoperative
cholangiography. One patient had a retained common duct stone successfully
managed with postoperative endoscopy. Laparoscopic subtotal cholecystectomy is a
safe and effective alternative to conversion to open cholecystectomy for severe
inflammation associated with acute cholecystitis. Endoscopic assessment and
treatment of common duct stones when indicated either before or after surgery
omits the use of intraoperative cholangiography and potential injury to the
inflamed ducts.
PMID- 9764699
TI - Epidemiology of immediate and early trauma deaths at an urban Level I trauma
center.
AB - The objective of this study is to identify and differentiate the injury patterns
and causes of death among patients who died within the 1st hour and those in the
period between 1 and 48 hours after hospital admission. Information was collected
from the 1994 to 1996 trauma data base at an urban Level I trauma center. The
records of 155 trauma patients who died within the 1st hour (immediate trauma
death, ITD) and between 1 and 48 hours (early trauma death, ETD) were examined
retrospectively. Total and constituent Injury Severity Score (ISS), Trauma Score
(TS), and Glasgow Coma Score were analyzed. ITDs constituted 49 per cent of all
deaths within 48 hours. Blunt mechanisms accounted for 37 per cent of ITDs and 40
per cent of ETDs (not significant), whereas penetrating trauma accounted for 59
per cent of ITDs and 56 per cent of ETDs (not significant). Exsanguination most
commonly caused death among ITDs (54%) and head injury (51%) among ETDs (P <
0.01). Patients who died within the 1st hour had higher ISS (42.6 +/- 23.2, P <
0.03), lower TS (1.7 +/- 1.9, P < 0.0001), and lower Glasgow Coma Score (3.1 +/-
1.1, P < 0.0001) than those who died after the 1st hour. Patients with ITD had a
significantly worse chest ISS than those with ETD (47.4 +/- 28.6 vs 19.0 +/-
19.1, P < 0.0001). We conclude that 1) ITD is caused primarily by exsanguination,
whereas ETD is largely due to the sequelae of severe neurologic injury; 2) ITD
has a significantly lower TS and higher ISS than ETD; and 3) thoracic injuries
are more severe among patients with ITDs than among those with ETDs. The severity
of thoracic injury among ITDs suggests that rapid surgical intervention is
critical during the resuscitation of these severely injured patients.
PMID- 9764701
TI - Use of rectal cancer position as a prognostic indicator.
AB - The hypothesis of this study was that the position of rectal cancer within the
circumference of the rectum influences mortality. Tumor position was
prospectively documented in 181 patients with rectal carcinoma by two examiners.
The results were analyzed for correlation to survival using the Lifetest model
and for multivariate correlation using the Cox regression model. An anterior
tumor location was present in 43 patients and was found to have a significantly
higher survival rate than other positions. Two-thirds of anterior tumors were of
pathologically favorable Dukes' stages. Fifty-five patients had posterior tumors
with decreased survival rates, two-thirds of which were of unfavorable stages.
Circumferential position in 61 patients was most predictive of poorer outcome,
with a relative risk of death being increased by 4.6 times (P = 0.014) and a 5
year survival rate of 68.8 per cent; 85 per cent of these tumors were of
pathologically unfavorable stages. The 5-year survival rate for the whole group,
which included 181 patients with all histopathological stages except those with
distant metastases at presentation, was 78.5 per cent. This ranking of survival
rates was found to be consistent in each category with the postoperatively
determined Dukes' stage, which carried a prognostic significance of P = 0.0001.
We conclude that tumor position is a significant indicator of prognosis available
before surgery for rectal cancer.
PMID- 9764703
TI - Herniography: a review of 333 herniograms.
AB - We reviewed 333 consecutive herniographic studies in 306 patients for whom
clinical data were available. Symptoms with either a negative or inconclusive
physical examination (PE) were the most frequent reasons for requesting a
herniogram. The herniogram was found to be more sensitive for the diagnosis of
hernia, particularly inguinal, than PE. In 56 of 57 patients who came to
operation the herniogram and the PE were concordant. In one patient, an
incisional hernia was found at operation that had not been appreciated as such on
the herniogram. We believe herniography should be used more frequently when the
diagnosis of hernia is uncertain on PE, thereby reducing the incidence of
unnecessary operative procedures.
PMID- 9764702
TI - Topical nitroglycerin in the management of anal fissure: an explosive outcome!
AB - Anal sphincter spasm is a common finding in patients with anal fissure disease.
It is postulated that spasm impedes mucosal blood flow and impairs healing.
Topical nitroglycerin (NTG), a nitric oxide donor compound, has been shown to
cause relaxation of the anal sphincter and may have treatment efficacy in the
management of anal fissure. The purpose of this study was to assess the
usefulness of NTG for anal fissure. We performed a retrospective review of
patients with anal fissure treated with various concentrations of topical NTG
ointments over an 18-month period ending July 1997. Of the 81 patients studied,
44 (54%) were male. There were 42 acute and 39 chronic fissures. NTG preparations
included 1 per cent isosorbide (n = 37), 0.2 per cent NTG (n = 38), and 0.5 per
cent NTG (n = 6). Healing with NTG therapy occurred in 29 acute (69%) and 21
chronic fissure (54%) patients. There was no difference in the incidence of
healing of acute or chronic fissure between the various NTG treatment preparation
groups. When acute and chronic fissure therapy was subdivided by time of NTG
treatment (immediate versus post-conservative therapy failure (PCF)), 14 (74%) of
acute PCF and 5 (42%) of chronic PCF patients healed. We conclude that no single
formula was superior. When patients were subdivided into a PCF group, NTG therapy
demonstrated a significant salvage rate, thus avoiding surgery.
PMID- 9764704
TI - Perforated appendicitis: is it truly a surgical urgency?
AB - Advanced perforated appendicitis with localized findings has classically been
treated with either operative therapy or with percutaneous drainage. The role of
nonoperative therapy followed by interval appendectomy (IA) remains
controversial. We assessed the safety and efficacy of conservative management for
perforated appendicitis in a 5-year review of patients treated conservatively for
perforated appendicitis with localized abscess or phlegmon. Patients were treated
initially with intravenous antibiotics, and CT-guided drainage was used only if
the patient failed to improve after 48 to 72 hours. Patients still not improving
underwent appendectomy. Patients responding to conservative therapy were
recommended IA in 6 to 12 weeks. Sixty-six patients with 54 abscesses and 10
phlegmons were treated. Fifty-one patients (92%) improved without surgery. Only
58 per cent of the abscesses required percutaneous drainage. The mean length of
stay for conservative therapy was 7.6 days. Forty-one patients underwent IA with
a 10 per cent morbidity and a mean length of stay of 1.4 days. Conservative
management of appendicitis with localized perforation or phlegmon is safe and
effective. Percutaneous drainage is frequently not required. IA is associated
with low morbidity without prolonged hospitalization.
PMID- 9764705
TI - Laparoscopy identifies unexpected groin hernias.
AB - Diagnostic laparoscopy performed before laparoscopic repair of groin hernias
offers an opportunity to examine all hernial orifices. This study was undertaken
to evaluate the accuracy of the preoperative clinical diagnoses and to determine
the frequency of unexpected groin hernias. Between December 1990 and November
1997, 253 patients (243 male) underwent laparoscopic repair of 560 hernias. The
total extraperitoneal technique was used in 93 per cent of the cases. Diagnostic
laparoscopy was performed before and after the preperitoneal dissection and
repair. Preoperatively, hernias were thought to be unilateral in 73 patients
(Group A) and bilateral in 180 patients (Group B). Incorrect diagnoses in 50 of
73 patients (68%) thought to have unilateral hernias included bilateral hernias
in 37 patients (50%), a different type of ipsilateral inguinal hernia in 7
patients (10%), or a femoral hernia in 6 patients (8%). Incorrect diagnoses in 91
of 180 patients (50%) thought to have bilateral hernias included a different
and/or additional type of ipsilateral inguinal hernia on either side in 63
patients (35%), a femoral hernia in 21 patients (12%), or a unilateral hernia in
7 patients (4%). Unexpected hernias that would not have been treated with an
anterior approach were found in 64 patients (25%; 27 were femoral and 37 were
contralateral). The laparoscopic technique allows for identification and repair
of previously undiagnosed contralateral and femoral hernias at the first
operation.
PMID- 9764707
TI - White blood cell count is a poor predictor of severity of disease in the
diagnosis of appendicitis.
AB - The white blood cell (WBC) count is considered to be a useful test in the
diagnosis of appendicitis. The purpose of this study was to examine the clinical
features of patients with normal WBC appendicitis and also to determine whether a
higher WBC count correlates with a more advanced stage of appendicitis. Patients
with pathologically confirmed appendicitis from January 1989 to December 1994
were included in the study (n = 1919). The age, gender, temperature, length of
hospital stay, and severity of disease (1 = acute appendicitis; 2 = gangrenous
appendicitis; 3 = perforated appendicitis with abscess formation; 4 =
appendicitis with diffuse peritonitis) were compared for patients with a normal
WBC count (range, 3.8-10.9) versus those who had an elevated WBC count. A normal
WBC count was seen in 11 per cent of patients (n = 209). There was no difference
in age, temperature, gender, or severity of disease in the patients with a normal
WBC count compared with those with an elevated WBC count (P > 0.05). The severity
of disease of patients with a normal WBC count were: 1 = 58 per cent; 2 = 13 per
cent; 3 = 7 per cent; and 4 = 22 per cent. For patients with an elevated WBC
count the scores were: 1 = 57 per cent; 2 = 17 per cent; 3 = 13 per cent; and 4 =
14 per cent. The proportion of gangrenous and perforated appendicitis in the
patients with a normal WBC count is the same as in the patients with an elevated
WBC count.
PMID- 9764706
TI - Diverting loop versus end ileostomy during ileoanal pullthrough procedure for
ulcerative colitis.
AB - A two-stage ileoanal pullthrough procedure (IAPP) is often used for patients with
ulcerative colitis (UC) requiring proctocolectomy. We analyzed the recent
University of California at Los Angeles experience with diverting end and loop
ileostomies in patients undergoing a two-stage IAPP. A retrospective analysis of
21 patients with UC undergoing loop ileostomy between March 1992 and March 1995
was performed. Comparison was made with 21 age- and gender-matched patients
undergoing end ileostomy between January 1991 and December 1995. There was no
mortality or major septic complications. A second laparotomy was required in all
patients with end ileostomies, whereas loop ileostomies were closed without
abdominal exploration. During ileostomy closure, operative time and mean hospital
stay were significantly reduced with the use of loop ileostomy. The time to oral
feeding was not significantly different between end and loop ileostomy groups
after ileostomy closure. The complication rate after IAPP was similar between
groups. However, after ileostomy closure, the complication rate was significantly
reduced with the use of loop ileostomy. We conclude that loop ileostomy is a
desirable option for UC patients undergoing intestinal diversion during IAPP.
Loop ileostomies can be created easily and without an increase in operative time.
Subsequent ileostomy closure can be performed as a local procedure, which may
shorten operative time and length of hospital stay.
PMID- 9764708
TI - Colonic stents in colorectal obstruction.
AB - Obstruction is the presenting symptom of colorectal cancer in up to 40 per cent
of patients. Benign strictures and other neoplasms including lymphoma and
gynecologic tumors occur as well. Emergent operative therapy is often suboptimal
and associated with significant morbidity and mortality. Our objective was to
review our experience with stent placement for colonic obstruction. Seven
patients underwent stent placement for a total of eight procedures. There were
three patients with unresectable colorectal cancer, two patients with metastatic
gynecologic cancer, one patient with rectal lymphoma, and one patient with
metastatic cancer of unknown primary. All colonic stents were Wallstents placed
by the same endoscopist under fluoroscopic and endoscopic guidance. Stents were
successfully placed in all patients without complication. One patient underwent
placement of two stents in succession for a long stenosis. Six of seven patients
(86%) had resolution of the obstruction and return of bowel function. Five of
seven were tolerating a diet within 24 hours. One patient's mental status did not
allow for oral intake. Four patients were discharged within 48 hours. Two
patients died within the same hospitalization as a result of metastatic disease.
One patient was found to have multilevel disease requiring stoma placement. There
was no morbidity or mortality associated with stent placement, and 86 per cent of
patients had palliation of the obstruction. We conclude that colonic stent
placement is a safe and effective therapy for colorectal obstruction at this
institution.
PMID- 9764709
TI - The use of technetium-labeled erythrocyte scintigraphy in the evaluation and
treatment of lower gastrointestinal hemorrhage.
AB - The percentage of incorrect operations performed as a result of technetium
labeled erythrocyte scintigraphy has been reported as high as 42 per cent. Recent
studies have found scintigraphy to be superior to angiography and propose that it
be used as the primary diagnostic test in patients with lower gastrointestinal
(GI) bleeding. A retrospective analysis was conducted of 105 patients with the
symptoms of lower GI hemorrhage to determine the effect of erythrocyte
scintigraphy on surgical management. Operative and pathology results were
analyzed to determine the accuracy of the scintigraphy for localization of the
bleeding source. In addition to tagged erythrocyte scans, 95 of 105 patients had
additional diagnostic procedures: colonoscopy (78), upper endoscopy (47), and
angiography (9). Scintigraphy localized a site of bleeding in 42 patients (colon,
29; jejunum/ileum, 10; duodenum, 2; esophagus, 1). Surgical intervention was
required in 25 patients, and the site of bleeding was correctly determined by
scintigraphy in 22 of these patients (88%). The scans were negative in two
patients, and the bleeding site was incorrectly reported in another. The patients
who had operations were significantly more likely to have positive scintigraphy
than the nonoperative group (P < 0.05). Preoperative localization of GI
hemorrhage is possible in most patients with technetium-labeled erythrocyte scans
(88% of operative patients). When combined with other tests to exclude upper GI
bleeding, scintigraphy is a reliable means of guiding surgical intervention.
PMID- 9764710
TI - Combined carotid endarterectomy and coronary artery bypass grafting in
asymptomatic carotid artery stenosis.
AB - The role of combined carotid endarterectomy (CEA) and coronary artery bypass
grafting (CABG) in patients with severe asymptomatic carotid artery disease and
concurrent symptomatic coronary artery disease is controversial. The objective of
this report is to investigate the safety of combined CEA/CABG. The medical
records of 30 patients who underwent combined CEA/CABG for coexistent
asymptomatic carotid and symptomatic coronary artery occlusive disease were
reviewed. All patients were scheduled for either elective or urgent myocardial
revascularization due to their symptomatic coronary artery disease. Color-flow
duplex scanning identified internal carotid artery stenosis of 80 to 99 per cent
in 28 patients (93%) and 50 to 79 per cent in 2 patients (7%). Seventeen patients
(57%) were male. The mean age was 64 +/- 10 years (range, 42-84 years).
Contralateral internal carotid artery occlusion was present in four patients.
Severe left main coronary artery disease was present in 12 patients (40%) and 7
patients (23%) had an ejection fraction of less than 50 per cent. There were no
perioperative deaths or strokes. One patient suffered a myocardial infarction on
postoperative day 1. This study demonstrates the safety of combined CEA/CABG for
coexistent coronary and asymptomatic carotid disease. Using this surgical
approach for critical coexistent disease may minimize the incidence of
perioperative cerebrovascular complications in patients undergoing CABG.
PMID- 9764711
TI - Carotid endarterectomy and abdominal aoritc aneurysm repair: are these reasonable
treatments for patients over age 80?
AB - Due to the aging of America, increased numbers of very elderly patients require
peripheral vascular surgery. From April 1980 to November 1997, 191 patients age
80 years or older had carotid endarterectomy (CEA) and/or abdominal aortic
aneurysm (AAA) repair at Loma Linda University Medical Center. The total
perioperative stroke and death rate in the CEA group was 2.9 per cent. Mean
postoperative cumulative survival in this group was 8.4 years. The cumulative
stroke-free survival rate was 95.5 per cent for all yearly postoperative
intervals up to 12 years. The perioperative mortality rate was 10.7 per cent in
the nonruptured AAA group and 53.8 per cent in the ruptured AAA group (P <
0.00001). Mean cumulative survival was 8.6 years in the nonruptured AAA group and
1.1 years in the ruptured AAA group (P = 0.0001). These data support the
conclusion that CEA and nonemergent AAA repair in octo- and nonagenarians are
safe and effective in prolonging stroke-free and rupture-free survival. The
utility of ruptured AAA repair in this age-group is less clear.
PMID- 9764712
TI - Wallgraft endoprosthesis: initial canine evaluation.
AB - This study evaluated the in vivo deployment and the healing characteristics of a
self-expanding endoluminal graft [Wallgraft (WG) Endoprosthesis] in a canine (n =
22) aorta. The WG consisted of a 10 or 12 mm x 7.5 cm Wallstents (Schneider,
Inc.) covered with polyethylene terephthalate (Dacron) graft material. Twenty-two
WGs were deployed using fluoroscopic guidance. Devices were oversized
approximately 10 per cent. Intravascular ultrasound (IVUS) was repeated, and
balloon expansion along the length of the WG was performed to assure maximum
expansion. WGs were evaluated with IVUS, angiography, and histology at 14 (n =
4), 30 (n = 4), 90 (n = 4), 180 (n = 5), and 365 (n = 5) days. Predeployment
aortic diameters were 9.9 +/- 1 mm. Mid-WG diameters were 9.0 +/- 0.8 mm before
balloon dilation and 9.2 +/- 0.5 mm after dilation with 8- (n = 1), 10- (n = 16),
and 12- (n = 5) mm balloons. Twenty-two of 23 devices were deployed accurately
with good apposition and aortic flow after deployment. On explant, all of the
covered grafts were widely patent on IVUS and angiogram. Four explants
demonstrated gaps (due to WG taper) between the proximal or distal ends of the
graft on IVUS. The device length (9.1 + 0.5 cm) did not change significantly
after deployment. Histologically at 6 months and 1 year the lumens were cell
lined. Scanning electron micrography demonstrated endothelial-like cells. This
study demonstrates the ability of a WG to be accurately deployed and maintain
excellent patency. Balloon expansion after deployment did not significantly
increase the diameter. Clinical evaluation of this device is in progress.
PMID- 9764713
TI - Surgical ligation of patent ductus arteriosus in very low birth weight infants:
is it safe?
AB - We evaluated the outcome of a combined medical and surgical treatment of patent
ductus arteriosus (PDA) in newborns weighing less than 1500 g. Charts were
retrospectively reviewed for 76 newborns with a PDA between 1993 and 1997.
Thirteen infants had pre-existing conditions prohibiting the use of indomethacin;
eight were managed surgically, five medically. The remaining 63 infants received
indomethacin therapy. Thirty-two medical failures occurred, requiring surgical
ligation of the PDA. Those requiring surgery had a lower average birth weight
(847 versus 997 g) and gestational age (26 versus 28 weeks; P < 0.05).
Indomethacin treatment was successful in 27 infants. There were only three
operative complications: a small pneumothorax, wound bleeding, and a small aortic
tear. All recovered uneventfully and no deaths were attributable to the surgical
procedure itself. There was no difference in the incidence of respiratory
distress syndrome, duration of intubation, sepsis, neonatal enterocolitis, renal
dysfunction, bleeding disorders, or intraventricular hemorrhage among both
groups. Surgical ligation of a PDA is associated with a high success rate, a low
incidence of complications, and no additional morbidity than indomethacin alone.
We propose that surgical ligation should be regarded as a first line therapy for
very small premature infants who are at higher risk of medical failure.
PMID- 9764714
TI - Lung volume reduction surgery: a cost and outcomes comparison of sternotomy
versus thoracoscopy.
AB - It remains unknown whether it is better to perform lung volume reduction surgery
(LVRS) through video-assisted thoracoscopy (VATS) or sternotomy. This study
compares both approaches in terms of surgical and patient outcomes as well as the
associated costs. All patients undergoing LVRS from 1995 to 1997 at one
institution by a single surgeon (PFW) were investigated. Preoperative,
postoperative, and cost data were obtained from medical and financial records. A
total of 42 patients with severe emphysema underwent LVRS (19 via sternotomy and
23 via thoracoscopy). Both groups were comparable preoperatively. Comparison of
intraoperative times revealed VATS takes longer to perform (sternotomy, 118 +/-
29 minutes; thoracoscopy, 168 +/- 20 minutes). Postoperatively, the sternotomy
patients had more days on the ventilator, more days in the intensive care unit,
more days with an air leak, and longer hospital stays. In both groups, the
majority of patients reported improvement in oxygen dependence as well as quality
of life. Neither surgical approach conferred any long-term medical advantage;
however, the average total hospital costs and charges were reduced in the VATS
group (average cost: VATS, $27,178; sternotomy, $37,299). This study concludes
that 1) LVRS seems to be beneficial for selected patients with end-stage
emphysema; 2) postoperative morbidity and length of hospital stay are decreased
in the VATS group; 3) long-term improvement in postoperative pulmonary function
is not influenced by surgical approach; and 4) the overall charges and costs of
the VATS approach is less than that of sternotomy.
PMID- 9764716
TI - Clinical pathways for general surgeons: emergency small bowel resection.
PMID- 9764715
TI - An early comparison between endoscopic ultrasound-guided fine-needle aspiration
and mediastinoscopy for diagnosis of mediastinal malignancy.
AB - Precise mediastinal lymph node staging is essential in non-small cell lung cancer
for proper evaluation and treatment. In addition to CT, mediastinoscopy is
routinely used for staging and diagnosis of mediastinal malignancy. Recently,
endoscopic ultrasound (EUS) combined with fine-needle aspiration (FNA) biopsy has
been used to evaluate mediastinal disease. The purpose of this study was to
assess and compare mediastinoscopy with EUS/FNA in the evaluation of mediastinal
masses. From August 1995 to July 1997, 21 patients with suspected mediastinal
malignancy underwent cervical mediastinoscopy with biopsy. During this same
period, seven patients with suspected mediastinal malignancy were evaluated using
EUS/FNA. All patients were retrospectively studied. Both mediastinoscopy and
EUS/FNA were highly sensitive in diagnosing mediastinal malignancy (100% and 86%,
respectively). Specificity and positive predictive value were 100 per cent for
both procedures. Mediastinoscopy and EUS/FNA are highly accurate methods of
staging mediastinal malignancy. Mediastinoscopy provides better access to the
upper and anterior mediastinum, whereas EUS/FNA can safely be used to biopsy
subcarinal and posterior mediastinal masses. Mediastinoscopy and EUS/FNA target
different areas of the mediastinum and may be complimentary in the evaluation of
mediastinal malignancy and staging of bronchogenic carcinoma.
PMID- 9764717
TI - Chronic sympathetic suppression in the treatment of chronic congestive heart
failure.
AB - Previous short-term studies demonstrated that treatment with clonidine produced
significant hemodynamic improvement in patients with congestive heart failure
(CHF). In this study we followed 12 CHF patients (10 M, 2 F age 63+/-11, 10 with
ischemic cardiomyopathy and 2 with dilated cardiomyopathy) treated with 0.15 or
0.075 mg oral clonidine twice daily for 13+/-5 months (range 6-23). with
functional evaluation at baseline, 6 weeks and 6 months. There was suppression of
circulating catecholamines, associated with significant ameliorations in NYHA
class, in duration of exercise tolerance (from 246+/-68 sec to 362+/-30 and 459+/
70 sec, respectively p < 0.02), in ejection fraction (from 32+/-7% to 35+/-5 and
39+/-7% p < 0.04) and in left ventricular enlargement as assessed
echocardiographically. There were also improvements in a number of
electrophysiologic parameters calculated by computerized analysis of ambulatory
ECG tapes, such as heart rate variability, indicating diminished propensity to
malignant arrhythmias, as confirmed by decreases in the numbers of isolated
premature ventricular contractions, couplets and episodes of non-sustained
ventricular tachycardia. The data suggest that chronic central sympathetic
suppression with clonidine in CHF results in significant functional amelioration
and improved electrophysiologic stability.
PMID- 9764718
TI - Dose-dependent reduction of myocardial infarct mass in rabbits by the NHE-1
inhibitor cariporide (HOE 642).
AB - The aim of this study was to investigate the dose-dependent effect of
pretreatment with the selective sodium-hydrogen exchange NHE-subtype 1 inhibitor
cariporide on myocardial infarct mass in a rabbit model of coronary ligation and
reperfusion. Furthermore, in a second part of the study, we tested the effect of
cariporide in the rabbits when given prior to reperfusion. Rabbits (n=49) were
randomized in 7 groups: saline vehicle, cariporide: 0.01, 0.03, 0.1 and 0.3
mg/kg, and subjected to a 30 min occlusion of a branch of the left coronary
artery followed by 2 h reperfusion. Cariporide was given as a bolus intravenously
10 min before occlusion or 5 min before reperfusion. After reperfusion,
myocardial infarct mass was determined by triphenyl tetrazolium chloride staining
and expressed as a percent of area at risk. Cariporide given intravenously 10 min
before occlusion in doses of 0.01, 0.03, 0.1, 0.3 mg/kg, led to a dose-dependent
reduction in infarct mass from 58+/-6% in controls to 48+/-4% (-17%, NS), 36+/-5%
(-38%, p<0.05), 26+/-6% (-55%, p<0.05), 11+/-4% (-81%, p<0.05) respectively,
whereas area at risk did not differ in between the groups. The effect of the
lowest dose of 0.01 mg/kg did not reach significance. Plasma levels at different
doses of cariporide were correlated to the respective infarct mass. After
coronary occlusion left ventricular end-diastolic pressure (LVEDP) significantly
increased throughout occlusion and reperfusion. Cariporide in the doses of 0.3,
0.1 and 0.03 mg/kg normalized LVEDP when measured after 2 h reperfusion. In
controls hemodynamic parameters such as mean arterial blood pressure (MAP), heart
rate (HR), left ventricular pressure (LVP) and LV dP/dt(max) were not
significantly changed by ischemia/reperfusion with the exception of MAP, LVP and
LV dP/dt(max) which were significantly decreased after 120 min reperfusion.
Cariporide at doses of 0.1, 0.03 and 0.01 mg/kg did not significantly influence
these parameters, whereas the highest dose of 0.3 mg/kg prevented the decrease of
MAP and LVP. Cariporide (0.3 mg/kg i.v.) administered 5 min before reperfusion
significantly reduced infarct mass by 31%. Under these conditions the increase of
LVEDP after coronary occlusion was not influenced by cariporide. As in the
pretreatment experiments, the decrease of MAP and LVP was prevented when measured
2 h after reperfusion. The results show that pretreatment with the NHE-subtype 1
inhibitor cariporide is cardioprotective by reducing infarct mass in rabbits in a
dose-dependent manner. While the cardioprotective effect of pretreatment could be
demonstrated over a broad range of doses, the efficacy of the compound when given
only on reperfusion was significant but more limited.
PMID- 9764719
TI - Effect of the vasodilatory beta-blocker, nipradilol, and Ca-antagonist,
barnidipine, on insulin sensitivity in patients with essential hypertension.
AB - OBJECTIVES: To assess the effects of a vasodilatory beta-adrenoceptor blocker,
nipradilol, and a long-acting Ca channel blocker, barnidipine, on insulin
sensitivity. DESIGN: Insulin sensitivity was determined using a euglycemic
hyperinsulinemic clamp technique before and after a 12-week treatment period in
eighteen patients with essential hypertension. RESULTS: Both drugs decreased
blood pressure without affecting any serum parameters of glucose and lipid
metabolism. Nipradilol significantly augmented glucose infusion rate (GIR) from
3.11+/-0.28 to 4.69+/-0.57mg/kg/min (p=0.027). Barnidipine also increased GIR
from 3.91+/-0.43 to 5.29+/-0.43 mg/kg/min (p=0.028). Plasma norepinephrine
concentrations significantly increased with barnidipine treatment, while
nipradilol had no effect on plasma norepinephrine levels. No adverse events were
reported during the study. CONCLUSIONS: These results suggest that vasodilatory
beta-blockers such as nipradilol and long-acting Ca channel blockers such as
barnidipine may be useful in the treatment of insulin resistant hypertensive
patients.
PMID- 9764720
TI - Comparative efficacies of a calcium antagonist and an alpha1 blocker in elderly
hypertensive patients with stroke.
AB - We compared the effects of nilvadipine, a calcium antagonist, and terazosin. an
alpha1 blocker, on the hemodynamics and quality of life (QOL) in 12 elderly
hypertensive patients with stroke. Following a washout period of 2 weeks.
nilvadipine or terazosin was administered for 2 weeks in a randomized crossover
manner. At the end of control and treatment periods, we measured the 24-hour
ambulatory blood pressure (BP) and postural change of BP, and interviewed QOL.
Terazosin treatment did not show consistent decrease of casual BP, but was
associated with a transient decrease of systolic BP and an increase of pulse rate
after standing, and enhanced postprandial decrease in BP. Nilvadipine decreased
casual BP in a dose-dependent manner, but showed neither postural nor
postprandial change of BP. There was no difference in QOL scores with either
treatment. Results suggest that nilvadipine is preferable to terazosin for the
treatment of elderly hypertensive patients with stroke.
PMID- 9764721
TI - Protective effects of valsartan and benazeprilat in salt-loaded stroke-prone
spontaneously hypertensive rats.
AB - These experiments examined the effectiveness of chronic blockade of the renin
angiotensin system with either valsartan or benazeprilat on survival, blood
pressure and end-organ damage in salt-loaded stroke-prone SHR. Valsartan or
benazeprilat given continuously by subcutaneous osmotic minipump beginning at
10.5 weeks of age lowered blood pressure, as determined by radiotelemetry,
prevented proteinuria, prolonged survival and decreased the severity of
histopathological changes in the heart and kidney. These results indicate that
angiotensin receptor blockade affords a similar degree of protection as
inhibition of angiotensin converting enzyme in salt-loaded stroke-prone SHR.
Furthermore, our results are consistent with a primary contribution of
angiotensin II to the maintenance of blood pressure and support a principal role
for angiotensin II-dependent mechanisms in the development of end-organ damage in
the salt-loaded stroke-prone SHR.
PMID- 9764722
TI - Hypertension development in Dahl S and R rats on high salt-low potassium diet:
calcium, magnesium and sympathetic nervous system.
AB - Dietary combination of high salt with low potassium (HSLK) exacerbates
hypertension development in Dahl salt-sensitive (S) rats, and produces a mild
degree of hypertension in otherwise salt-resistant (R) rats. Increased blood
pressure in both strains is associated with increased urinary excretion of
calcium and magnesium. The objective of this study was to determine the effect of
blood pressure on body balance of these ions in Dahl rats on HSLK diet. Two
groups of S and two groups of R weanlings were all placed on HSLK diet (NaCl=8%,
K=0.2%) for eight weeks. One group of each strain was subjected to chemical
sympathectomy with 6-hydroxydopamine (6-OHDA) to counteract hypertension
development. Urinary norepinephrine was used to determine efficacy of 6-OHDA
treatment. Systolic blood pressures of conscious animals were measured daily
throughout the study. The last three days on the diet were used to determine
total dietary intake and urinary as well as fecal excretion of sodium, calcium
and magnesium. At the end of the study, extracellular fluid volume, serum
aldosterone and parathyroid hormone were analyzed. Final systolic blood pressures
in the 4 groups were as follows: S=235+/-9 mmHg (n=9); R=155+/-3 mmHg (n=8); 6
OHDA S=151+/-6 mm Hg (n=8); 6-OHDA R=117+/-6 mm Hg. Chemical sympathectomy
decreased blood pressure in both S and R rats. There was no indication of sodium
accumulation in S rats. Associated with reduced parathyroid hormone levels the S
strain had significantly less positive balance for calcium than the R strain,
primarily due to increased urinary excretion. A less positive balance for
magnesium was also observed, due mainly to relatively reduced intestinal
absorption of the ion. We conclude that the HSLK diet is associated with
inappropriate activation of the sympathetic nervous system and increased arterial
pressure in both strains. In addition, since divalent cations may influence blood
pressure, we suggest that the observed abnormalities in calcium and magnesium
metabolism might independently promote hypertension development in the S strain.
PMID- 9764723
TI - Development of monoclonal antibodies to erythroid progenitors in feline bone
marrow.
AB - Feline bone marrow cells can be enriched for erythroid and myeloid progenitors by
counterflow centrifugal elutriation (CCE) and subsequent treatment of the CCE
fractions with the soybean agglutinin (SBA) lectin. Separation of CCE fractions
into SBA(-) and SBA(+) populations yielded cells enriched for BFU-E and CFU-GM
progenitors, respectively. Differential analyses revealed a high percentage of
erythroid lineage cells in the SBA(-) fractions and in the SBA(+) fractions a
high concentration of myeloid cells of varying maturation stages. The latter
cells, but not the CFU-GM progenitors, could be removed by immunomagnetic
depletion from CCE fractions using a monoclonal antibody (MAb) specific for CD13
cells in feline bone marrow, resulting also in a population containing
predominantly erythroid differentiating cells. Mice were immunized with CCE
fractions enriched for erythroid lineage cells and the splenocytes fused with
SP2/O cells for hybridoma development. Supernatant culture fluids from 400
hybridomas were analyzed by flow cytometry with whole bone marrow and select
CCE/SBA fractions as the target cells. Those hybridomas suggestive of containing
the desired antibodies as indicated by the percentage staining were subcloned and
the MAbs utilized in clonogenic assays. Treatment of bone marrow cells or CCE
fractions with the MAbs followed by immunomagnetic depletions led to
identification of two, K-1 and Q-3, reactive with the BFU-E progenitor and one, K
7, reactive only with late-differentiating erythroid lineage cells. Thus, removal
of cells from a CCE/SBA suspension reactive with K-1 or Q-3 led to greater than
80% reductions of the BFU-E progenitors and a population enriched for CFU-GM.
Removal of cells reactive with MAb K-7, however, led to a marked enrichment, 5-8
fold, of both BFU-E and CFU-GM progenitors.
PMID- 9764724
TI - Interactions between lipopolysaccharides and blood factors on the stimulation of
equine polymorphonuclear neutrophils.
AB - In horses, the mechanisms of lipopolysaccharide (LPS) stimulation of isolated
neutrophils to produce reactive oxygen species remain unknown. We re-investigated
this problem by monitoring the luminol-enhanced chemiluminescence (CL) produced
by LPS-stimulated equine neutrophils. The neutrophils were isolated from horse
blood by discontinuous density gradient centrifugation (> or = 99% neutrophils;
viability > or = 98%). Increasing concentrations of Escherichia coli (E. coli)
LPS (from 0.01-10 microg ml(-1)) were used to activate the neutrophils. When LPS
was used directly, without another stimulator, the respiratory burst of
neutrophils was not activated (N=12 horses; n=5 assays per horse). On the
contrary, when LPS was added to whole blood, the neutrophils isolated from this
blood were stimulated in a LPS dose-dependent manner, but polymyxin B added to
whole blood suppressed this stimulation (N=2; n=6). LPS dissolved in autologous
equine plasma stimulated the isolated neutrophils in a dose-dependent manner from
0.1-10 microg ml(-1) (N=5; n=12). Heat inactivation of the plasma abolished this
CL increase (N=2; n=5). LPS added to equine albumin did not stimulate the
isolated neutrophils (N=2; n=5). On the contrary, the addition of gamma-globulins
(1 mg ml(-1)) to LPS (10 microg ml(-1)) led to the stimulation of neutrophils
(N=2; n=5). We concluded that LPS did not directly stimulate the isolated equine
neutrophils, but that plasmatic factors are needed for the stimulation of these
cells by LPS.
PMID- 9764725
TI - Modulation of lympho-proliferative responses of ovine peripheral blood
mononuclear cells by Mycoplasma mycoides ssp. mycoides (LC type).
AB - The present study was carried out to investigate the immunomodulating potential
of M. mycoides ssp. mycoides (Mmm) (LC): a standard strain (Y-Goat, YG) and a
local strain (M30) isolated from the pneumonic lung of a lamb during an outbreak
of respiratory disease. The study was conducted in two parts to determine in
vitro and in vivo aspects of the Mmm-induced modulation of cellular immune
responses. In vitro experiments, using peripheral blood mononuclear cells (PBMC)
of naive lambs, showed that live (Lv) or inactivated (Ina) antigens of Mmm
(strains YG and M30) were not mitogenic for PBMC. Live antigens of both the
strains, however, induced significant suppression of the PHA-driven lympho
proliferative (LP) responses. Suppression of LP responses by infectious Mmm (both
strains) was restored in the presence of exogenous recombinant human interleukin
2 (rhIL-2). Following experimental inoculation of lambs with Mmm (YG), a
significant reduction in non-specific LP responses was observed on days 6, 10 and
14 post inoculation (p.i.). There was a slow but significant rise in memory LP
responses to Mmm strains (YG and M30). Specific subset depletion studies, using
immunomagnetic cell separation (IMCS) technique, carried out on days 10 and 14
p.i., revealed that the OvCD4+ cell population was the main proliferating
lymphocyte subset following an infection with Mmm (LC type).
PMID- 9764726
TI - Immunohistochemical study of the local immune response to Fasciola hepatica in
primarily and secondarily infected goats.
AB - The distribution of CD2, CD4, CD8, gamma/delta T-lymphocytes, B-cells and IgG
lambda-light chain (lambda-IgG) containing cells were analysed in the
inflammatory infiltrate associated to hepatic lesions and gallbladder (HL), and
in hepatic lymph nodes (HLN) of goats primarily and secondarily infected with
Fasciola hepatica. In the HL, CD2 and CD8 T-cells were more numerous (p=0.01) in
secondarily rather than in primarily infected goats, whereas CD4 T-lymphocytes
were less numerous than CD8 and showed no significant change in both groups. The
ratio CD4/CD8 was 0.66 and 0.39 for primarily and secondarily infected goats,
respectively. In contrast, in the HLN, CD4 were more numerous than CD8 T-cells,
the ratio CD4/CD8 was 2.0 in control, 1.5 and 1.3 in primary and secondary
infections, respectively. Gamma/delta T-lymphocytes were scarce in the HL and
moderate in the HLN of both primarily and secondarily infected animals. B-cells
(IgM+, lambda-IgG+ or CD79+) varied from scarce or moderate in the HL to abundant
in the HLN, where CD79+-cells were mainly located in lymphoid follicles and IgM
and IgG in plasma-cells of the medullary cords, suggesting an intense local
humoral immune response. However, this response did not prevent the hepatic
damage in secondarily infected goats, in which hepatic lesions were more severe
than in primarily infected ones.
PMID- 9764727
TI - Characterisation of the primary local and systemic immune response in gnotobiotic
lambs against rotavirus infection.
AB - This study characterised the primary immune response in gnotobiotic lambs after
infection with a lamb rotavirus (RV). Lambs were infected and killed over a 7
week period together with controls. RV-ELISA and neutralising antibodies were
determined in serum, nasal secretions, and intestinal scrapings. RV-antibody
secreting cells (ASC) were enumerated in blood. Lymphocyte proliferations were
determined in blood and gut-associated lymphoid tissues and cytokine expression
was analysed in jejunal Peyer's patches (JPPs) and mesenteric lymph nodes (MLNs).
Infected lambs cleared the virus by 8-9 days after infection without showing any
clinical signs. The first indication of a specific immune response to RV was an
increased expression of IL-4 mRNA in the JPPs in the infected group compared to
the control group 3 days after infection. Rotavirus-specific IgA ASC in blood and
IgA antibodies in serum and nasal secretions were detected from 7 days after
infection followed at 10 days after infection by RV-specific IgG ASC and
antibodies. Rotavirus-specific IgA antibodies were not detected in intestinal
scrapings in the first 10 days after infection, but were detected by 52 days
after infection. No RV-specific neutralising antibodies were seen in the
intestine during the course of the experiment.
PMID- 9764728
TI - Immunity to porcine rubulavirus infection in adult swine.
AB - The immune response against the porcine rubulavirus was analyzed in
experimentally infected adult pigs. High titers of virus neutralizing and
hemagglutinating inhibitory antibodies were identified in infected animals. The
antibody specificity was directed towards HN, M, and NP rubula virion proteins;
immunodominance of HN proteins was demonstrated. Peripheral blood mononuclear
cells from infected, but not from non-infected pigs proliferated in vitro in
response to virus antigenic stimuli, showing a bell-shaped plot with the highest
peak at 5 weeks post-infection. Virus-induced lymphoblasts expressed CD4+ CD8+
phenotype, whereas lectin-induced lymphoblasts were mainly identified as CD4+ CD8
cells. Phenotype analysis of freshly prepared PBMC revealed increased number of
both monocytes (PoM1+) and total T lymphocytes (CD2+) early during infection,
with reduced values of B lymphocytes at 4 weeks post-infection. Decrease in CD4+
CD8- blood cells was observed at 3 weeks post-infection, whereas both CD4- CD8+
and CD4+ CD8+ cells increased 1 and 4 weeks post-infection, respectively. This
work discusses the relevance of CD4+ CD8+ T cells in the control of porcine
rubulavirus infection.
PMID- 9764729
TI - Characterisation of non-maternal serum proteins in amniotic fluid at weeks 16 to
18 of gestation.
AB - Proteins found in amniotic fluid are mainly serum proteins, probably of maternal
origin. About 5% of the total protein concentration has the potential of being
fetal or decidual in origin. Only a few of these proteins have been isolated and
characterised. In order to describe the foetal and decidual components in
amniotic fluid more extensively, a polyspecific antiserum to amniotic fluid at
weeks 16-18 of gestation was raised. Specificities in the antiserum to serum
proteins were removed by adsorption. Several proteins of non-serum protein origin
reacted with the antiserum. Three of these proteins were chosen for isolation and
further characterisation. With the use of immunological methods, SDS-PAGE and N
terminal sequencing we identified two of the proteins as C-terminal propeptides
of procollagen Type I and Type III, which have not hitherto been described in
amniotic fluid. The third protein, called here protein-4, showed up as homologous
to fetal antigen-1 (FA-1) and human dlk, containing EGF-like domains and
associated with growth in neuroendocrine tissues and tumours.
PMID- 9764730
TI - Valproate and carbamazepine comedication changes hepatic enzyme activities in
sera of epileptic children.
AB - Previous observation that valproic acid (VPA) and carbamazepine (CBZ) caused
hepatic damage prompted us to investigate the effects of VPA or CBZ monotherapy
and VPA + CBZ comedication on the number of hepatic enzyme activities in sera of
epileptic children. This study compares alanine aminotransferase (ALT), aspartate
aminotransferase (AST) and gamma-glutamyltransferase (GGT) activities in sera of
children treated with VPA (n=42), or CBZ (n=36) taken as a monotherapy, with VPA
+ CBZ combined therapy (n=36). The effect of VPA alone is greater on the activity
of AST than on other enzymes, while CBZ therapy changes primarily the activities
of GGT. The mean catalytic activity of AST was significantly elevated in groups
on VPA, CBZ and VPA + CBZ treatment (2.02-, 1.49- and 1.45-fold increase,
respectively) as compared to the control values. Changes in the ALT activity
followed different patterns. The maximal increase was observed in the CBZ group
with a smaller increase in the group on VPA + CBZ polytherapy, whereas only 15%
of patients receiving VPA showed an average 1.38-fold increase of the mean enzyme
activity. Increase in the catalytic activity of GGT probably reflects the
induction produced by the CBZ treatment, either alone or in combination. Children
on CBZ monotherapy showed an increase of mean catalytic activity of about twofold
in 56% of patients. Children on VPA + CBZ comedication showed a similar
behaviour, while VPA alone produced a moderate (1.44-fold) increase in 23% of
children. However, concentrations of VPA and CBZ in sera of patients receiving
monotherapy were within the expected therapeutic limits, whereas subtherapeutic
levels of VPA were found in 30% of children on VPA + CBZ comedication. We propose
that individual dosage adjustment in VPA + CBZ polytherapy should be combined
with monitoring of relevant enzyme activities in serum.
PMID- 9764731
TI - Reported alcohol consumption and the serum carbohydrate-deficient transferrin
test in third-year medical students.
AB - The serum carbohydrate-deficient transferrin (CDT) test was performed on 143
third-year medical students along with questionnaires for the self-reporting of
alcohol consumption during the last 2 weeks, the last 6 months, and questions on
any alcohol-related untoward events. We found that the CDT test has poor
sensitivity for detecting binge drinking in our population of students, despite
some likely under-reporting of drinking. Self-reporting of drinking is commonly
unreliable, and we found no significant correlation between the CDT
concentrations in serum and the magnitude of self-reported alcohol use during 2
week and 6-month periods. Hangover was by far the commonest self-reported
untoward event, and there was a highly significant relationship (P < 0.001)
between drinking and untoward events. From a small population of non-drinkers, we
estimated the reference ranges for CDT to be <27 U/l for men and <35 U/l for
women.
PMID- 9764732
TI - Modulation of LDL particle size after an oral glucose load is associated with
insulin levels.
AB - Individuals with a predominance of small low-density lipoprotein (LDL) particles
appear to be at increased risk for coronary artery disease. The purpose of this
study was to determine whether the LDL particle size was modulated in response to
a 75-g oral glucose load. Overall, there were no significant changes in the LDL
particle size after glucose load. However, the difference in LDL particle size
(deltaLDL size) between the fasting and 2-h post-load states was inversely
correlated with the fasting LDL particle size. Also, deltaLDL size was positively
correlated with BMI and the post-load glucose levels. Forward stepwise regression
analysis revealed three parameters as independent factors capable of modulating
LDL particle size: BMI, fasting insulin, and post-load glucose levels. After
adjustment for BMI and glucose levels, the levels of fasting and 2-h post-load
insulin remain independent determinants of deltaLDL size. These results suggest
that plasma insulin levels during glucose load modulate LDL particle size.
PMID- 9764733
TI - Radio-enzymatic determination of histamine: interference by fluoride and possible
activation of histamine methyl transferase.
AB - The reproducibility of a radio-enzymatic method for determining plasma histamine
was found to be affected by the anti-coagulant used for collecting blood.
Recovery experiments from whole blood indicated that heparin yielded values that
were more accurate than with EDTA or sodium fluoride; fluoride gave a mean value
which was +41% higher than with heparin (P=0.054). Addition of fluoride to a
standard calibration curve, and of increasing amounts to aliquots of 5 ng
histamine also yielded higher values than in controls, up to +15% (P<0.1) and
+14.1% (P=0.03) respectively. Fluoride did not affect the detecting system and
was not contaminated with histamine; nor did it breakdown the methyl donor, S
adenosyl-L-methionine. It is concluded that heparin is the anti-coagulant of
choice and that fluoride may activate histamine methyl transferase from pig
brain. Fluoride may possibly have a biological role as an enzyme-activator and a
usefulness in the therapy of mastocytosis.
PMID- 9764734
TI - Levels of lipid peroxidation product and glycated hemoglobin A1c in the
erythrocytes of diabetic patients.
AB - In diabetes, the glycation and subsequent browning (or glycoxidation) reactions
are enhanced by elevated glucose concentrations. It is unclear whether or not the
diabetic state per se also induces an increase in the generation of oxygen
derived free radicals (OFRs). There is some evidence, however, that glycation
itself may induce the formation of OFRs. OFRs could cause oxidative damage to
endogenous molecules. We examined the relationship between the levels of lipid
peroxidation and the levels of glycated hemoglobin A1c (GHbA1c) in erythrocytes
of diabetic and healthy subjects. Lipid peroxidation was assessed in erythrocyte
membrane lipids by monitoring peak height ratios of conjugated linoleic acid
(CLA), one of the products of lipid peroxidation, to linoleic acid (LA) using gas
chromatography-mass spectrometry (GC/MS). CLA is a collective term used to
designate a mixture of positional and geometric isomers of LA in which the double
bonds are conjugated. The peak height ratio of CLA to LA was used as a biomarker
of lipid peroxidation. GHbA1c, an index of glycemic stress, was measured by high
performance liquid chromatography. There were significantly increased ratios of
CLA to LA in diabetic erythrocytes compared with control erythrocytes. These
ratios of CLA to LA were also significantly correlated with GHbA1c values. This
suggests that glycation via chronic hyperglycemia links lipid peroxidation in the
erythrocytes of both diabetic and healthy subjects.
PMID- 9764735
TI - Effect of cigarette smoking on plasma metalloproteinase-9 concentration.
PMID- 9764736
TI - Chronological change of respiratory function in smokers with elevated serum
carcinoembryonic antigen levels.
PMID- 9764738
TI - Introduction of the Guest-Editors with a short review on history of optics in
Jena.
PMID- 9764737
TI - Trypsin digestion of histones inhibited by glucose.
PMID- 9764739
TI - Scanning near-field optical microscopy in cell biology and microbiology.
AB - Scanning a point light source in close proximity over a sample and recording the
scattered or transmitted light intensity point by point allows one to record
optical images with a resolution not limited by diffraction. An overview of this
technique called scanning near-field optical microscopy (SNOM or NSOM) is given
with emphasis on cell- and microbiology. After an introduction, where the basic
features of the technique are explained, illustrative examples are presented,
such as a HeLa cell, fluorescence labelled human chromosomes, super resolution
fluorescence imaging, single molecule imaging and fluorescence resonance energy
transfer between a single pair of dye molecules.
PMID- 9764740
TI - Cell biological applications of scanning near-field optical microscopy (SNOM).
AB - Scanning near-field optical microscopy (SNOM) yields high-resolution topographic
and optical images and is an important technique for visualizing biological
systems. We summarize the literature on SNOM of biological systems and present
some of our recent applications in cellular biology. These include studies of: i)
the binding of fluorescently conjugated lectins to cell surface glycoproteins on
3T3 Balb/c cells, ii) molecular interactions by fluorescence resonance energy
transfer using photobleaching techniques, and iii) green fluorescent protein
(GFP) expressed in bacteria.
PMID- 9764741
TI - Laser tweezers and optical microsurgery in cellular and molecular biology.
Working principles and selected applications.
AB - After focusing in a microscope, light can be used for micromanipulation of (sub
)micrometer sized objects. Focused beams of classical light ablate elements of
the cell division machinery and switch the beating of hearts on a cellular basis.
Focused lasers (laser microbeams or optical scissors) allow in addition very
precise nanomachining in a wide field of applications, from developmental biology
to plant biotechnology. While in microbeam work high power densities and
efficient light-tissue interactions are required, optical tweezers work in a
complementary way: Moderate power densities and small absorption of the laser by
the biological material is needed. With light pressure and optical gradient
forces optical tweezers can be used to move microscopic objects, even in the
interior of closed cells. In total, most mechanical micromanipulation techniques
known from cellular and molecular biology can be replaced by their optical
correlate and some applications are possible which cannot be performed
micromechanically. When these optical microtools are operated at their maximum
performance, the physical effects are as interesting as their biological
applications: The laser microbeam can generate extreme local temperatures, which
however are dissipated within a few tens of nanoseconds and therefore cause
damage only very locally. The optical tweezers with a working wavelength in the
optical window of biological material (600-1100 nm) exert piconewton forces
without any mechanical contact. The present article discusses some quantitative
physical aspects of microbeams and optical tweezers and gives a few selected
examples of applications.
PMID- 9764742
TI - Cell ablation studies in plant development.
AB - As an alternative and complementary approach to genetic targeted ablation, laser
ablation has been applied to a variety of plant systems to investigate the basics
of development in plants. The recent relevant literature is reviewed and provides
concrete examples of how root development in Arabidopsis and cell polarization in
Fucus have been studied using laser microsurgery. Guidelines are proposed for
researchers who would like to apply laser ablation techniques to a given
developmental problem.
PMID- 9764743
TI - Laser tweezers are sources of two-photon excitation.
AB - The most important application of continuous wave (cw) near infrared (NIR)
microbeams in cellular and molecular biology are single-beam gradient force
optical traps, also called "laser tweezers". Laser tweezers have been used for
optical picoNewton force determination as well as for 3D cellular and
intracellular micromanipulation, such as optical spermatozoa transportation in
laser-assisted in vitro fertilization. Light intensities in the MW/cm2 range are
necessary to confine motile spermatozoa in the optical trap. The enormous photon
concentration in space and time results in non-resonant two-photon excitation of
endogenous and exogenous absorbers with electronic transitions in the ultraviolet
and visible spectral range. Trap-induced two-photon excitation of intracellular
flurorophores can be used to study metabolism and vitality of motile cells
without additional fluorescence excitation sources. Therefore, laser tweezers as
sources of two-photon excitation may act as novel non-linear tools in cell
diagnostics. The far red/NIR trapping radiation, in particular <800 nm, may also
excite endogenous absorbers such as NAD(P)H, flavins, porphyrins and cytochromes.
Excitation of these cellular absorbers may result in oxidative stress via type I
and type II photooxidation processes. Severe non-linear-induced cell damage in a
variety of cells confined in <800 nm traps was found. Two-photon induced
destructive effects are enhanced in multimode traps due to longitudinal mode
beating phenomena. Pulsed laser sources are not suitable for safe optical
trapping of living cells. The use of single frequency long-wavelength NIR traps
(800 nm-1200 nm) for vital cell handling is recommended.
PMID- 9764744
TI - Laser micromanipulation systems as universal tools in cellular and molecular
biology and in medicine.
AB - The UV-laser microbeam has been established as a valuable tool in a wide area of
molecular biology as well as in medical research and applications. This system
allows to cut or fuse microscopically small specimen. An important application of
the cutting laser is laser microbeam microdissection (LMM) combined with laser
pressure catapulting (LPC), which allows to procure single cells or small
homogeneous cell areas for subsequent molecular analysis in an entirely "non
contact" manner. With LMM minute tissue areas, single cells or chromosomes are
microdissected and separated from their surroundings. Subsequently, LPC ejects
the dissectates directly into the cap of a sample tube without any mechanical
contact. This enables the rapid procurement of homogeneous specimen from less
than one up to several hundreds of micrometers in diameter without encroachment
of the adjacent region. The mRNA information of the selected specimen as well as
of the remaining probe are well preserved, as demonstrated with laser isolated
samples from a routinely prepared tissue section of a differentiated colorectal
adenocarcinoma. Reverse transcription of specific mRNA coding for cytoplasmic
beta-actin and subsequent hemi-nested PCR amplification was not impaired. Any
kind of tissue, as well as single cells from different sources and even
subcellular structures can be captured using this laser method. Wherever
homogeneous samples are required to analyze cell or chromosome-specific genetic
alterations such as in cancer research or prenatal diagnosis this unique and
rapid laser micropreparation method will become a key technology of great value.
PMID- 9764745
TI - Optical tweezers in pharmacology.
AB - Current applications of optical tweezers in pharmacology are presented. The
manufacture of cellular biosensor arrays employing optical tweezers is reviewed.
Using this technique, a new approach to cellular drug screening, based on single
cells patterned with the laser tweezers was introduced. Specific stimulation of
different immobilized, viable cells could be shown simultaneously. Furthermore,
the usefulness of optical tweezers for analyzing the interactions of ligands with
cellular membrane receptors is demonstrated. The laser tweezers could
successfully be used to compare neuron interactions with glycoproteins of the
extracellular matrix by applying the optical tweezers as picotensometer. The
forces of interactions between polystyrene beads coated with different proteins
of the extracellular matrix and the cell membrane receptors of cerebellar neurons
from postnatal day 6 (P6) mice were measured. When antibodies to the
extracellular matrix proteins were added, forces were significantly reduced for
the corresponding antigens but not for the other glycoproteins. This proved the
specificity of the measured interactions. Information regarding the receptor
anchorage of tenascin-C could be deduced.
PMID- 9764746
TI - Time-gated autofluorescence microscopy of motile green microalga in an optical
trap.
AB - Ultrafast time-gated fluorescence imaging of optically trapped single motile
cells is presented. The biflagellar green microalga Haematococcus pluvialis was
confined with picoNewton trapping forces in the focal volume of a high numerical
aperture objective by near infrared multitraps. Trapping radiation of 100 mW
power at the sample was provided by a Nd:YLF laser (1047 nm) operating in the cw
mode. Simultaneously, cellular autofluorescence was excited with a 633 nm
picosecond 80 MHz laser diode. An ultrafast gated intensified slow scan CCD
camera system with a tunable gate width (200 ps-1 ms) and tunable time-delay (0
20 ns) between excitation and detection was used as fluorescence detector. We
demonstrate fluorescence imaging of high temporal (sub-ns) and high spatial (sub
microm) resolution and fluorescence lifetime determination of intracellular
autofluorescence based on chlorophyll excitation. Exposure to the herbicide DCMU
resulted in an increase of fluorescence intensity and lifetime by 250% and 150%,
respectively.
PMID- 9764747
TI - New time-resolved techniques in two-photon microscopy.
AB - Microscopy is traditionally a tool for determining biological structures. Many
recent advances in optical microscopy involves the incorporation of spectroscopy
techniques to monitor biochemical states of microscopic structures in living
cells and tissues. By minimizing tissue photodamage, two-photon excitation
microscopy provides a new opportunity to study the dynamics of biological systems
on time scales from nanoseconds to hours. This review will focus on a number of
these new methods: two-photon time-lapse microscopy, two-photon photoactivation,
two-photon correlated spectroscopy, two-photon single particle tracking and two
photon lifetime microscopy.
PMID- 9764748
TI - Time-gated fluorescence microscopy in cellular and molecular biology.
AB - An experimental set-up for time-gated fluorescence spectroscopy and microscopy is
described, and some recent applications in cellular and molecular biology are
summarized. Selective detection of intrinsic fluorophores, in particular
nicotinamide adenine dinucleotide (NADH) and flavins was demonstrated in living
cells. Non-radiative energy transfer from reduced NADH to the mitochondrial
marker rhodamine 123 was evaluated for probing mitochondrial malfunction in
living cells. An increase of "energy transfer efficacy" up to a factor 4 was
detected after inhibition of enzyme complexes of the respiratory chain. Two
different fluorescence lifetimes of calcium orange were evaluated, whose relative
intensities depended on calcium concentration. Therefore, fluorescence measured
within two different time gates appeared to be suitable for ratio fluorometry of
calcium. Time-gated fluorescence spectra of the membrane marker laurdan showed
more pronounced changes than steady state spectra when temperature was increased
from 24 degrees C to 38 degrees C. This may improve measurements of intracellular
temperature. Time-gated detection of small amounts of porphyrins and their
discrimination from a large fluorescent background caused by chlorophyll in
transgenic tobacco plants again proved the advantages of time-gated fluorescence
spectroscopy.
PMID- 9764749
TI - Laser scanning microscopy in enzyme histochemistry. Visualization of cerium-based
and dab-based primary reaction products of phosphatases, oxidases and peroxidases
by reflectance and transmission laser scanning microscopy.
AB - The reflectance mode of confocal laser scanning microscopy is suitable to detect
cerium-based primary reaction products of oxidases (CeIV-perhydroxide) and
phosphatases (CeIII-hydroxy-phosphate converted into CeIV-perhydroxy-phosphate)
as well as of DAB-based primary reaction products (Ni-DAB, Ni-FeII-DAB and CeIV
DAB complexes) of cytochrome C oxidase and peroxidases in vibratome, cryotome and
semithin plastic sections. In combination with confocal detection 3D images with
submicron spatial resolution can be obtained. Moreover, CeIV-perhydroxide, CeIV
perhydroxy-phosphate, CeIV-DAB complexes and catechol-DAB polymers are highly
absorptive. Among other additives, especially stable nitroxyl radicals led to a
distinct improvement of the DAB staining in terms of sensitivity and proper
localization. This was proven in addition by means of blotting a horseradish
peroxidase dilution series during several experiments. In sections it was easily
possible to record reflectance signals and high transmission contrast at the
wavelength of the exciting argon ion laser (preferentially 488 nm). The results
of an imbibition study of cerium-containing model precipitates indicate that the
cerium generally should be oxidized prior to observation because the index of
refraction of CeIV compounds is considerably higher than that of the
corresponding CeIII compounds. A comparative numerical assessment of reflection
intensities from reflectant parts in morphologically similar sections is
possible. Confocal laser scanning microscopy offers a unique way for high
resolution detection of primary histochemical reaction products being
sufficiently reflective and/or absorptive. The proposed techniques may open new
methodological possibilities for basic research and for medical diagnosis.
PMID- 9764750
TI - Acousto-optic random-access laser scanning microscopy: fundamentals and
applications to optical recording of neuronal activity.
AB - A novel approach to laser scanning microscopy is presented that utilizes
diffraction-based scanning principles to achieve fast random-access positioning
of a focused laser beam. This non-imaging approach overcomes the speed limitation
of present reflection-based scanning microscopes while maintaining high spatial
resolution. The presented system combines conventional video microscopy with fast
non-imaging scanning microscopy. Together with readily available optical
indicators of neuronal activity, this system permits multi-site optical recording
from living brain tissue. In this paper, we will review the underlying principles
of laser scanning microscopy and the steps in development that led to the current
acousto-optic scanning system. We will present typical signals recorded with the
current system, and we will outline ongoing extensions of the system. We will
also discuss the present limitation of this instrumentation and look into
directions of future development.
PMID- 9764751
TI - Fluorescence correlation microscopy (FCM)-fluorescence correlation spectroscopy
(FCS) taken into the cell.
AB - Confocal fluorescence correlation spectroscopy (FCS) and other confocal
spectroscopic techniques are ideally suited for the analysis of molecular
interactions at the subcellular level. However, one requires exact positioning in
three dimensions within the cell. Our instrument integrates FCS with high
sensitivity digital imaging microscopy and high precision positioning. We present
first measurements of intracellular FCS, with specification of the instrumental
requirements and methods of data analysis. We propose the term fluorescence
correlation microscopy (FCM) for this extended modality of FCS.
PMID- 9764752
TI - Fluorescence correlation spectroscopy as a tool to investigate chemical reactions
in solutions and on cell surfaces.
AB - Taking advantage of the present day possibilities for ultrasensitive detection by
fluorescence, fluorescence correlation spectroscopy (FCS) has over the last ten
years emerged as a potentially very powerful technique. In this article we
present some results to illustrate the use of FCS for monitoring chemical
kinetics on a molecular level and show how, for a wide range of chemical
processes, the theoretical treatment can be strongly simplified. The experimental
examples given include measurements of ion concentrations and buffer properties,
electron transfer reactions, ligand-receptor interactions and diffusion of ligand
receptor complexes in cell membranes. For each of these examples the properties
of the FCS technique is discussed in relation to other established techniques
used for that particular application. From these examples it is found that FCS
can offer important complementary information and, due to the extreme sensitivity
of the technique, new information not yet explored by other methods.
PMID- 9764753
TI - Stress symposium in Johannesburg: plants versus humans.
AB - On 18 February 1998, a 'Stress symposium' was held at the Rand Afrikaans
University (RAU) in Johannesburg, South Africa. The meeting brought together
people from both the plant and the human oxidative stress field, which was
exemplified by a talk entitled 'Heat shock proteins in host-pathogen
interactions: plants versus humans'. There were moments when it appeared as if
the main difference between plants and humans was, as sung by Julos Beaucarne,
that 'the human plant is the only one to be able to water itself...'
PMID- 9764754
TI - Phosphorylation of RNA polymerase II C-terminal domain (CTD): a new control for
heat shock gene expression?
PMID- 9764755
TI - Stimulation of the stress-induced expression of stress proteins by curcumin in
cultured cells and in rat tissues in vivo.
AB - Curcumin, a major component of turmeric, a seasoning commonly used in Indian
food, and a known antioxidant, anti-inflammatory and anti-carcinogenic agent, is
a potent stimulator of the stress-induced expression of Hsp27, alphaB crystallin
and Hsp70. When C6 rat glioma cells were exposed to arsenite (100 microM for 1
h), CdCl2 (100 microM for 1 h) or heat (42 degrees C for 30 min) in the presence
of 3-10 microM curcumin, induction of the synthesis of all three proteins was
markedly stimulated, as detected by specific immunoassays, Western blot analysis
and Northern blot analysis. A gel mobility shift assay revealed that curcumin
prolonged the stress-induced activation of the heat shock element-binding (HSE
binding) activity of heat shock transcription factor (Hsf) in the cultured cells.
The stimulatory effect of curcumin on the responses to stress was also observed
in BRL-3A rat liver cells and Swiss 3T3 mouse fibroblasts. Induction of Hsp27,
alphaB crystallin and Hsp70 in the liver and adrenal glands of heat-stressed (42
degrees C for 20 min) rats was also enhanced by prior injection of curcumin (20
mg/kg body weight). As curcumin is a potent inhibitor of arachidonic acid
metabolism, it is suggested that the mechanism of the stimulation by curcumin of
the stress responses might be similar to that of salicylate, indomethacin and
nordihydroguaiaretic acid.
PMID- 9764756
TI - Presence of antibodies to heat stress proteins in workers exposed to benzene and
in patients with benzene poisoning.
AB - Heat shock or stress proteins (Hsps) are a group of proteins induced by a large
number of xenobiotics, many of which are common in the working and living
environment. The biological significance of the presence of antibodies against
Hsps in humans is presently unknown. In the present study, 112 workers were
selected and divided into four groups on the basis of their level of occupational
exposure to benzene: a control group, two groups of workers exposed to either low
(< 300 mg/m3) or high concentrations of benzene (> 300 mg/m3) and a group of
workers who had experienced benzene poisoning. Blood samples from these workers
were assayed for the number of peripheral white blood cells, concentration of
hemoglobin, activities of serum superoxide dismutase (SOD), lymphocyte DNA damage
and finally for the presence of antibodies to different human heat-shock proteins
(Hsp27, Hsp60, Hsp71 and Hsp90). Benzene-poisoned workers showed a high incidence
of antibodies against Hsp71 (approximately 40%) which was associated with a
decrease in white blood cells (3.84+/-1.13 x 10(9)versus 7.68+/-1.84 x 10(9) in
controls) and with an increase in activities of serum SOD (138.43+/-23.15
micro/ml) and lymphocyte DNA damage (18.7%). These data suggest that antibodies
against Hsps can potentially be useful biomonitors to assess if workers are
experiencing or have experienced abnormal xenobiotic-induced stress within their
living and working environment.
PMID- 9764757
TI - Flow cytometry is a rapid and reliable method for evaluating heat shock protein
70 expression in human monocytes.
AB - The increasing interest in stress/heat shock proteins (Hsps) as markers of
exposure to environmental stress or disease requires an easily applicable method
for Hsp determination in peripheral blood cells. Of these cells, monocytes
preferentially express Hsps upon stress. An appropriate fixation/permeabilization
procedure was developed, combined with immunofluorescence staining and flow
cytometry for the detection of the inducible, cytosolic, 72 kDa Hsp (Hsp70) in
human monocytes. Higher relative fluorescence intensity was observed in cells
exposed to heat shock (HS), reflecting a higher expression of Hsp70 in these
cells as compared with cells kept at 37 degrees C. The heat-inducible increased
Hsp70 expression was temperature- and time-dependent. Expression of Hsp70 was not
uniform within the monocyte population, indicating the presence of subpopulations
expressing variable levels of Hsp70 in response to HS. Simultaneous measurements
of intracellular Hsp70 and membrane CD14 expression revealed that the higher
Hsp70 inducibility coincided with the higher CD14 expression. Comparisons
performed with biometabolic labelling, Western blotting, immunofluorescence and
immunoperoxidase microscopic analysis, showed a high concordance between these
different methods; however, cytometry was more sensitive for Hsp70 detection than
Western blotting. Flow cytometric detection of intracellular Hsp70 is a rapid,
easy and quantitative method, particularly suited for the determination of
protein levels in individual cells from an heterogeneous population such as
peripheral mononuclear blood cells, and applicable to cohort studies.
PMID- 9764758
TI - Phosphorylation is not essential for protection of L929 cells by Hsp25 against
H2O2-mediated disruption actin cytoskeleton, a protection which appears related
to the redox change mediated by Hsp25.
AB - Small stress proteins protect against the cytotoxicity mediated by oxidative
stress. The relationship between Hsp25 expression and the integrity of the actin
network was studied in H2O2-treated murine L929 fibrosarcoma cells overexpressing
endogenous wild-type (wt-) or non-phosphorylatable mutant (mt-) Hsp25. We show
here that both proteins prevented actin network disruption induced by a 1 h
treatment with 400 microM H2O2. In contrast, SB203580, a p38 MAPkinase inhibitor
which suppresses Hsp25 phosphorylation, abolished the protective activity
conferred by both wt- and mt-Hsp25. Hence, phosphorylation does not appear
essential for Hsp25 protective activity against H2O2-induced actin disruption,
and SB203580-sensitive events other than Hsp25 phosphorylation may be important
for actin network regulation. Since, in L929 cells, wt- or mt-Hsp25 expression
modulates intracellular glutathione levels, analyses were performed which
revealed a direct correlation between glutathione and the integrity of the actin
network. Moreover, laser scanning confocal immunofluorescences revealed that only
a small fraction of wt- or mt-Hsp25 colocalized with actin microfilaments. Taken
together, our results suggest that, in L929 cells, the protection against actin
network disruption is probably a consequence of the redox change mediated by
Hsp25 rather than a direct effect of this stress protein towards actin.
PMID- 9764760
TI - Purification and characterization of chaperonins 60 and 10 from Methylobacillus
glycogenes.
AB - Two proteins belonging to the group I chaperonin family were isolated from an
obligate methanotroph, Methylobacillus glycogenes. The two proteins, one a GroEL
homologue (cpn60: M. glycogenes 60 kDa chaperonin) and the other a GroES
homologue (cpn10: M. glycogenes 10 kDa chaperonin), composed a heteropolymeric
complex in the presence of ATP. Both proteins were purified from crude extracts
of M. glycogenes by anion-exchange (DEAE-Toyopearl) and gel-filtration (Sephacryl
S-400) chromatography. The native molecular weights of each chaperonin protein as
determined by high-performance liquid chromatography (HPLC) gel-filtration were
820 000 for cpn60 and 65 000 for cpn10. Sodium dodecyl sulfate-polyacrylamide gel
electrophoresis revealed that the subunit molecular weights of cpn60 and cpn10
were 58 000 and 10 000, respectively. Both cpn60 and cpn10 possessed amino acid
sequences which were highly homologous to other group I chaperonins. M.
glycogenes cpn60 displayed an ATPase activity which was inhibited in the presence
of cpn10. The chaperonins also displayed an ability to interact with and
facilitate the refolding of Thermus malate dehydrogenase and yeast enolase in a
manner similar to that of GroEL/ES. The similarities between the Escherichia coli
GroE proteins are discussed.
PMID- 9764759
TI - Constitutive expression of heat shock proteins Hsp90, Hsc70, Hsp70 and Hsp60 in
neural and non-neural tissues of the rat during postnatal development.
AB - Heat shock proteins (Hsps) are a group of highly conserved proteins, that are
constitutively expressed in most cells under normal physiological conditions.
Previous work from our laboratory has shown that neurons in the adult brain
exhibit high levels of Hsp90 and Hsc70 mRNA and protein, as well as basal levels
of Hsp70 mRNA. We have now investigated the expression of Hsp90, Hsc70, Hsp60 and
Hsp70 in neural and non-neural tissues of the rat during postnatal development, a
time of extensive cell differentiation. Western blot analysis revealed
constitutive expression of these Hsps early in postnatal development.
Developmental profiles of these Hsps suggest that they are differentially
regulated during postnatal development of the rat. For example, while levels of
Hsp90 decrease somewhat in certain developing brain regions, levels of Hsp60 show
a developmental increase, and Hsc70 protein is abundant throughout postnatal
neural development. Low basal levels of Hsp70 are also observed in the developing
and adult brain. A pronounced decrease in Hsp90 and Hsc70 was observed during
postnatal development of the kidney while levels of Hsp60 increased. In addition,
tissue-specific differences in the relative levels of these Hsps between brain
and non-brain regions were found. Immunocytochemical studies demonstrated a
neuronal localization of Hsp90, Hsc70 and Hsp60 at all stages of postnatal
development examined as well as in the adult, suggesting a role for Hsps in both
the developing and fully differentiated neuron. The developmental expression of
subunit IV of cytochrome oxidase was similar to that of Hsp60, a protein
localized predominantly to mitochondria.
PMID- 9764761
TI - Complementary and alternative medicine: essential for the future of effective,
affordable healthcare?
PMID- 9764762
TI - Big changes at National Cancer Institute.
PMID- 9764763
TI - New chair of alternative medicine at the State Medical University of Crimea in
Simferopol, Ukraine.
PMID- 9764764
TI - A lost opportunity to discover antibiotics.
PMID- 9764765
TI - Effects of lavender straw on stress and travel sickness in pigs.
AB - OBJECTIVE: To observe pigs during road journeys in order to establish whether
lavender straw was likely to decrease stress and incidence of travel sickness.
SUBJECTS: Forty 70-kg Large White pigs were transported by road for 2 hours, 20
animals each day, over a 2-day period. DESIGN: On day 1, ample wheat straw was
provided as bedding such that the floor of the vehicle was entirely covered
(straw condition). On day 2, lavender straw was provided as bedding (lavender
condition). During the journey, direct behavioral observations of the
individually marked pigs were made by scanning every 10 minutes for incidence of
standing and lying along with the less severe symptoms of travel sickness
(foaming at the mouth and repetitive chomping). Incidences of retching and
vomiting were noted as they occurred. A general activity index was also scored
every 10 minutes (5 = high activity, 1 = low activity). Saliva samples were taken
from each animal at different stages of the journey for analysis of cortisol.
RESULTS: Pigs stood more when in the straw condition, but were more active when
standing in the lavender condition. Symptoms of travel sickness appeared to be
less acute in the lavender condition, with more animals exhibiting the less
severe symptom, foaming and chomping (a total of 3 in straw compared with 6 in
lavender), but fewer animals showing the more severe symptoms of retching and
vomiting (in straw, 3 retched, 6 vomited; in lavender 0 retched, 3 vomited). A
total of 6 animals retched or vomited in the straw condition but only 3 in the
lavender. There was a significant difference in mean concentrations of cortisol
between conditions but this was due to a difference in mean baseline
concentrations between groups. CONCLUSION: Addition of lavender straw appeared to
decrease incidence and severity of travel sickness but not overall levels of
stress (as measured by concentrations of salivary cortisol).
PMID- 9764766
TI - Characteristics of users and nonusers of alternative medicine in dermatologic
patients attending a university hospital clinic: a short report.
AB - OBJECTIVES: To study the characteristics of users of alternative medicine in
dermatologic outpatients attending a university clinic. DESIGN: A cross-sectional
study analyzed by using a case-control methodology. SETTING, SUBJECTS, AND STUDY
MEASURES: 118 dermatologic patients attending an outpatient university clinic
responded to a structured questionnaire concerning demographic data, medical
history, experience with alternative medicine, health beliefs, lifestyle, and
locus of control. RESULTS: Thirty-five percent of the patients reported having
used some form of alternative medicine. Use was related to disease duration, but
not to patients' beliefs regarding whether or not they could influence their own
health, nor to dissatisfaction with orthodox medicine. The most common reason for
trying alternative medicine was that they "wanted to try everything" in an
attempt to cure the skin disease. Users stated to a greater extent than nonusers,
that they exercised sufficiently, possibly indicating that they are more health
conscious. CONCLUSIONS: The study suggests that dermatologic patients using
alternative medicine in general do not differ with regard to personal
characteristics from nonusers. Rather, it appears that patients with long
standing skin disease turn to alternative medicine as a complement to orthodox
treatment.
PMID- 9764767
TI - Treatment of human immunodeficiency virus-positive patients with complementary
and alternative medicine: a survey of practitioners.
AB - OBJECTIVE: To investigate complementary and alternative medicine (CAM) practices
provided to human immunodeficiency virus (HIV)-infected individuals, provider
experience in HIV disease, patients' characteristics, provider perceptions of
treatment effectiveness, and feasibility and interest in future studies. DESIGN:
Mailed survey. PARTICIPANTS: 117 providers, recruited from professional
associations and conferences, who offer CAM therapies to HIV-infected
individuals. OUTCOME MEASURES: Provider credentials, patient descriptors,
treatments prescribed and their perceived effectiveness, health service
information, medical information charted, and research participation capability
and interest. RESULTS: Providers are treating patients at all stages of HIV
disease with a variety of CAM practices, claiming a mean of 6.5 years of HIV
disease treatment experience and 105 HIV-positive patients in treatment per
provider (solo practice or clinic). Eighty percent of respondents report holding
state licenses to practice. A total of 115 different CAM therapies with an
average of 12 treatments per provider were used. Ninety percent of providers
claimed their therapies were "somewhat" to "very effective" on all disease
stages, indicating effectiveness for symptom management (96%), quality of life
(98%), raising or maintaining CD4+ lymphocyte levels (66%), slowing progression
to acquired immunodeficiency syndrome (AIDS) (69%), and extending survival (73%).
Research readiness and willingness was reported by a majority of respondents.
CONCLUSIONS: Providers with substantial experience treating HIV disease with a
range of CAM practices claim effectiveness for their methods. Providers are
generally willing to participate in studies that would examine such claims and
appear to have the capacity meaningfully to contribute. These claims should be
investigated.
PMID- 9764768
TI - The scientific rediscovery of an ancient Chinese herbal medicine: Cordyceps
sinensis: part I.
AB - This review presents Cordyceps sinensis (Berk.) Sacc., a fungus highly valued in
China as a tonic food and herbal medicine. The extant records show the continued
use of C. sinensis is now centuries old. The major chemical, pharmacological, and
toxicological studies on C. sinensis and the various derived, cultured, fermented
mycelial products currently in use are reviewed from the English and Chinese
literature. Preclinical in vitro and in vivo studies and clinical blinded or open
label trials in to date over 2000 patients are reviewed. These studies show the
main activities of the fungus in oxygen-free radical scavenging, antisenescence,
endocrine, hypolipidemic, antiatherosclerotic, and sexual function-restorative
activities. The safety of the fungus, its effects on the nervous system, glucose
metabolism, the respiratory, hepatic, cardiovascular, and immune systems,
immunologic disease, inflammatory conditions, cancer, and diseases of the kidney
will be reviewed in the second part of this article to be published in the winter
issue of this journal.
PMID- 9764769
TI - Aspects of ethnobotanical medicine in southeast Nigeria.
AB - OBJECTIVE: To document the diversity and traditional use of tropical plants as
medicine by the indigenous people of southeast Nigeria. DESIGN: Information was
obtained by interviews conducted with the aid of questionnaires and facilitators
during field surveys carried out from January 1993 to June 1994. Voucher
herbarium specimens were identified at the University of Nigeria, Nsukka
Herbarium, in collaboration with Bernhard Zepernick (former Curator), Botanisches
Museum, Berlin. Specimens were photographed. RESULTS: Data are summarized in the
form of a table, summarizing the plants commonly used by the traditional doctors
or medicine men. Herbal preparations are arranged alphabetically under family and
species. The data are presented in the order: botanical name, collection number,
vernacular name, locality, plant habit/status, and reported medicinal
applications.
PMID- 9764770
TI - Traditional alternatives as complementary sciences: the case of Indo-Tibetan
medicine.
AB - Traditional medical systems, like those preserved in Asia, pose a challenge
because they involve theories and practices that strike many conventionally
trained physicians and researchers as incomprehensible, even nonsensical. Should
modern medicine continue to dismiss these systems as unscientific, therefore
worthy of debunking rather than serious study; view them as sources of
alternatives, possibly effective but hidden in a matrix of prescientific custom
and belief; or do they represent something like a complementary science of
medicine? We make the latter argument using the example of Indo-Tibetan medicine.
Indo-Tibetan medicine is based on analytic models and methods that are rationally
defined, internally coherent, and make testable predictions, therefore meeting
current definitions of "science." The possibility of multiple, complementary
sciences is a consequence of certain findings in physics that have led to a view
of science as a set of tools-instruments of social activity that depend on
learned agreement in aims and methods-rather than as a monolith of absolute
objective truth. Implications of this pluralistic view of science for medical
research and practice are discussed.
PMID- 9764772
TI - M.D. programs in the United States with complementary and alternative medicine
education: an ongoing listing.
PMID- 9764771
TI - Reflections on the nature of the consultation.
PMID- 9764773
TI - Adaptation to promiscuous usage of CC and CXC-chemokine coreceptors in vivo
correlates with HIV-1 disease progression.
AB - OBJECTIVE: To study coreceptor usage of sequential primary HIV-1 isolates in a
longitudinal follow-up cohort of HIV-1-infected men to understand its
contribution to pathogenesis of HIV disease. DESIGN: Viral coreceptor usage of
sequential primary isolates from HIV-1-infected individuals was examined at
various timepoints and data was compared with CD4 cell counts, rates of disease
progression and beta-chemokine production. METHODS: Fifty-eight sequential
primary isolates were obtained from four rapid progressors, six late progressors,
and three long-term nonprogressors (LTNP) and their coreceptor usage was examined
by infection of peripheral blood mononuclear cells (PBMC) from donors with wild
type or non-functional CC-chemokine receptor (CCR)-5, and by infection of GHOST4
cells expressing CD4 and various chemokine receptors [CCR-1-CCR-5, CXC-chemokine
receptor (CXCR)-4, BOB/GPR15, BONZO/STRL33]. Production of RANTES and macrophage
inflammatory protein (MIP)-1beta was examined using unstimulated or
phytohemagglutinin (PHA)-stimulated PBMC isolated from these individuals at
multiple timepoints during infection. RESULTS: A switch from single CCR-5
coreceptor usage to multiple coreceptor usage occurred in all four rapid
progressors and three out of six late progressors. In addition to the commonly
used coreceptors CXCR-4, CCR-5, and CCR-3, some of the viruses isolated from
patients in the terminal stage of infection also used CCR-1, CCR-2b, CCR-4, and
BOB as coreceptors. The emergence of viral variants capable of utilizing multiple
coreceptors generally preceded CD4 cell decline to < 200 x 10(6)/l and correlated
with the onset of AIDS. In contrast, three LTNP maintained exclusive usage of CCR
5 over a period of 7-12 years post-infection. Endogenous production of RANTES and
MIP-1beta by PBMC from LTNP was not significantly different from rapid and late
progressors. However, PHA-driven production of both chemokines was significantly
higher in LTNP, suggesting that in vivo activating stimuli might curtail HIV
replication by inducing these chemokines. CONCLUSIONS: Viral variants capable of
utilizing a broad range of coreceptors correlated with HIV-1 disease progression.
In contrast, LTNP maintain exclusive usage of CCR-5 and produce higher levels of
beta-chemokines. Thus, both viral and host determinants leading to the emergence
of viral variants capable of using an expanded range of coreceptors may be likely
determinants of disease progression.
PMID- 9764774
TI - Target cell availability and the successful suppression of HIV by hydroxyurea and
didanosine.
PMID- 9764775
TI - Cost-effectiveness and cost-benefit in the prevention of mother-to-child
transmission of HIV in developing countries. Ghent International Working Group on
Mother-to-Child Transmission of HIV.
PMID- 9764776
TI - Prognostic significance of plasma markers of immune activation, HIV viral load
and CD4 T-cell measurements.
AB - OBJECTIVE: To evaluate the prognostic significance for AIDS occurrence of plasma
levels of immune activation markers in comparison with and in conjunction with
HIV viral load and CD4 T-cell measurements. DESIGN: A retrospective analysis was
conducted of three plasma activation markers, the soluble tumor necrosis factor
(TNF) receptor II (TNF-RII), neopterin and soluble interleukin-2 receptor levels,
and of CD4 T-cell levels and plasma HIV viral load. SUBJECTS: The participants
were 659 men taking part in the University of California Los Angeles Multicenter
AIDS Cohort Study who were HIV-seropositive but AIDS-free in 1985. MAIN OUTCOME
MEASURE: Clinically defined AIDS within 3 years. Failure time statistical
regression models for the time to development of AIDS were used to assess
prognostic capacity of the parameters alone and in combination. RESULTS: All the
markers had prognostic capability. The levels of the three plasma activation
markers correlated well with each other (median r = 0.61). They related less well
with HIV RNA plasma levels (median r = 0.50) and least well with CD4 cell levels
(median r = 0.36). Furthermore, plasma marker levels were shown to be able to
stratify patients for prognosis within all the major categories of CD4 T-cell and
HIV RNA levels. CONCLUSIONS: Plasma levels of soluble TNF-RII and other soluble
markers of immune activation have prognostic capabilities which are different
from HIV and CD4 T-cell levels. Combination of a single plasma activation marker
measurement (such as soluble TNF-RII) with CD4 T-cell levels improved the
prognostic capability of each. A new graphic technique for presenting prognostic
capability indicated that plasma soluble TNF-RII and CD4 cell levels are better
prognostic factors than HIV plasma level with CD4 cells < 200 x 10(6)/l.
Inexpensive tests for one of the plasma activation markers, such as soluble TNF
RII or neopterin, can be useful for evaluations of HIV disease course, especially
when expensive equipment, technical expertise and funding required for flow
cytometry and for HIV load measurements are not readily available.
PMID- 9764777
TI - Neutralizing antibodies are positively associated with CD4+ T-cell counts and T
cell function in long-term AIDS-free infection.
AB - OBJECTIVES: To assess the dynamics of neutralizing antibodies (NAb) in long-term
AIDS-free HIV-1-infected subjects and establish correlations with known markers
of disease progression. DESIGN: Cross-sectional study using sera collected from
long-term non-progressors (LTNP) 8 years after seroconversion or study entry.
Longitudinal study using sera collected from LTNP at 0, 0.5, 1, 2, 4, 6, 8 and 10
years after seroconversion and, as controls, from rapid progressors. METHODS:
Individuals with documented AIDS-free HIV-1 infection for at least 8 years were
evaluated for NAb against five heterologous HIV-1 primary isolates. In the cross
sectional study, serum viral RNA levels, CD4+ T-cell numbers and T-cell function
were determined on samples collected during the eighth year of follow-up. For the
longitudinal study, NAb were assessed in sequential sera taken from LTNP and
rapid progressors. RESULTS: Serum neutralization titres found in individual sera
differed from one HIV-1 isolate to another, were detected in 49-76% of LTNP,
without correlation with the coreceptor usage of the isolate, and were positively
associated with CD4+ T-lymphocyte counts (P = 0.0041) and T-cell function (P =
0.04). No correlation was found between NAb and the level of viral RNA in serum
or the rate of CD4+ T-cell decline. Longitudinal analysis of sera from LTNP and
rapid progressors showed that although several subjects in both groups had
neutralizing activity at seroconversion, it thereafter became lower or no longer
detectable. NAb were again found 1-4 years later and stably persisted in LTNP,
but remained undetectable or at low levels in rapid progressors. CONCLUSIONS: NAb
were preferentially found in subjects with relatively preserved T-cell function
and CD4+ T-cell numbers. In these individuals, neutralizing activity against
heterologous isolates increased with time. These data suggest that the capacity
to produce broadly NAb is a function of the integrity of the immune system.
PMID- 9764778
TI - Change in fluconazole susceptibility patterns and genetic relationship among oral
Candida albicans isolates.
AB - OBJECTIVE: To assess the genetic homogeneity or heterogeneity within each set of
Candida albicans isolates colonizing/infecting the oral cavities of HIV-infected
patients undergoing azole therapy when changes in susceptibility to fluconazole
were detected. DESIGN: Fourteen HIV-positive patients suffering recurrent
episodes of oral candidosis were prospectively followed from the first episode to
the isolation of strains with decreased susceptibility to fluconazole. The
strains of C. albicans isolated either from episodes or controls throughout the
prospective study were analysed. METHODS: Electrophoretic karyotyping and
hybridization with the repeated sequence probe 27A were used to delineate
sequential isolates. In vitro susceptibility tests to fluconazole and
ketoconazole were also performed. The results obtained by DNA fingerprinting with
the probe combined with computer-assisted analysis were used to assess the
genetic relationships amongst the strains. In addition, comparison with the
genetic relatedness of a group of geographically unrelated strains was made.
RESULTS: Isogenic populations of sequential isolates were observed only in two
patients; 12 patients harboured heterogenic populations over time, although in 11
patients there was a predominant strain that was isolated more than once, and
only one of these patients carried strains with a similarity index less than 80%.
With the exception of two patients, each patient carried a major strain that
became less susceptible to fluconazole. The similarity index for the unrelated
strains was 59%. CONCLUSIONS: HIV-infected patients may carry a mixed population
of strains, but the strains tend to be related to each other. The strains were
maintained throughout the course of infection and at least one developed
secondary resistance to fluconazole.
PMID- 9764779
TI - HIV protease genotype and viral sensitivity to HIV protease inhibitors following
saquinavir therapy.
AB - OBJECTIVE: To examine the relationship between HIV protease genotype and altered
protease inhibitor sensitivity of isolates from patients after therapy with
saquinavir (SQV) in its hard gelatin formulation. DESIGN: Forty-one post-therapy
isolates and corresponding baseline samples were obtained from 37 patients in
four different clinical trials after therapy with SQV for 16-147 weeks. Post
therapy isolates were selected on the basis of preliminary sequence or drug
sensitivity data. RESULTS: Fifteen out of 17 isolates without detectable Val-48
or Met-90 mutations retained sensitivity to SQV. (The remaining isolates showed
only a marginal increase in median inhibitory concentration.) In addition, three
out of 15 isolates with Met-90 retained sensitivity to all other protease
inhibitors tested (indinavir, ritonavir, amprenavir, nelfinavir). Of the isolates
showing reduced sensitivity to SQV, six out of 22 retained sensitivity to all
other protease inhibitors, whereas only four out of 22 showed broad cross
resistance to all protease inhibitors tested. The reduction in sensitivity
correlated closely with the presence of Val-48 or Met-90. Subsequent accessory
substitutions were also linked to reduced sensitivity. However, significant
linkage was observed only between mutations at residues 48 and 82 and between
those at residues 82 and 74. CONCLUSIONS: Recruitment of Val-48/Met-90 mutations
was not found to be synonymous with cross-resistance. Indeed, the majority of
isolates with these mutations retained sensitivity to at least one protease
inhibitor (Val-48, 86%; Met-90, 77%). The recruitment of accessory mutations may
occur only after the selection of key resistance mutations. Furthermore, Met-90
was found to be a poor marker of cross-resistance in SQV-treated patients.
PMID- 9764780
TI - Suppression of plasma viral load below 20 copies/ml is required to achieve a long
term response to therapy.
AB - BACKGROUND: Current guidelines state that the goal of antiretroviral therapy for
HIV-infected individuals is to suppress plasma viral load (pVL) to below 400
copies/ml. METHODS: Predictors of achieving and maintaining pVL suppression were
examined in a randomized trial of combinations of zidovudine, nevirapine and
didanosine in patients with CD4+ T cell counts of between 200 and 600 x 10(6)
cells/l who were naive to antiretroviral therapy and AIDS-free at enrolment.
RESULTS: One hundred and four patients had pVL > 500 copies/ml at baseline and a
pVL nadir below 500 copies/ml. Of these, 77 patients experienced an increase in
pVL above 500 copies/ml. The median number of days of pVL suppression to below
500 copies/ml was 285 (42) for patients with pVL nadir < or = (>) 20 copies/ml (P
= 00.0001). The relative risk of an increase in pVL above 500 copies/ml
associated with a pVL nadir below 20 copies/ml was 0.11 (P = 0.0001). The
relative risks of an increase in pVL above 5000 copies/ml associated with a pVL
nadir below 20 copies/ml or between 20 and 400 copies/ml were 0.05 [95%
confidence interval (CI), 0.02-0.12] and 0.37 (95% CI, 0.23-0.61) respectively,
compared with individuals with a pVL nadir > 400 copies/ml. Individuals with a
pVL nadir < or = 20 copies/ml were at a significantly lower risk of virologic
failure than individuals with a pVL nadir of between 21 and 400 copies/ml (P =
0.0001). CONCLUSIONS: Our results demonstrate that suppression of pVL below 20
copies/ml is necessary to achieve a long-term antiretroviral response. Our data
support the need for a revision of current therapeutic guidelines for the
management of HIV infection.
PMID- 9764781
TI - Treatment response and durability of a double protease inhibitor therapy with
saquinavir and ritonavir in an observational cohort of HIV-1-infected
individuals.
AB - OBJECTIVE: To evaluate treatment response, durability and tolerance of a four
drug regimen including saquinavir and ritonavir in combination with either
zidovudine/lamivudine or stavudine/lamivudine. DESIGN: Observational cohort of
HIV-positive individuals. METHODS: Viral load, CD4+ and CD8+ T lymphocyte counts
were assessed at intervals of 1-3 months in subjects commencing therapy between
July 1996 and November 1996. Adverse events were evaluated as well as risk
factors for therapeutic failures. RESULTS: A group of 56 male patients were
included and followed for 48 weeks. Of these, 66% had already taken a protease
inhibitor. Viral load dropped by a median 1.98 log10 HIV RNA copies/ml from
baseline (interquartile range: 1.49-2.46) and became undetectable (< 400
copies/ml) in 68% of patients. Response varied: 9% were non-responders (HIV RNA
reduction < 0.5 log10 copies/ml) and 23% were incomplete responders (nadir of HIV
RNA > 400 copies/ml). After 48 weeks, viral load remained undetectable in 49%.
Median CD4+ T lymphocyte count increased from 191 x 10(6) to 418 x 10(6) cells/l
(range, 241-537 x 10(6) cells/l). Although protease inhibitor and nucleoside
pretreatment selected for drug-resistant viral mutants, only the protease
inhibitor experience was identified as a risk factor for therapeutic failure.
Adverse events occurred in 73% of patients and led to a change of therapy in 9%.
CONCLUSION: Despite advanced HIV disease and pretreatment with multiple
antiretroviral drugs, a strong initial treatment response to this drug regimen
was observed. However, virological failure occurred in 51% of patients after 48
weeks and frequent adverse events complicated therapy.
PMID- 9764782
TI - Clinical outcome and predictive factors of failure of highly active
antiretroviral therapy in antiretroviral-experienced patients in advanced stages
of HIV-1 infection.
AB - OBJECTIVE: To verify the effectiveness of highly active antiretroviral therapy
(HAART) and to identify any factors predictive of clinical outcome in a clinical
setting. DESIGN: Observational study. METHODS: Treatment failure (i.e., the
occurrence of new or recurrent AIDS-defining events, death or any definitive
discontinuation) and the course of CD4+ cell counts and HIV RNA copies were
evaluated in 250 heavily pretreated HIV-infected patients starting HAART [153
with indinavir (IDV), 55 with ritonavir (RTV), 43 with saquinavir (SQV)].
Univariate and multivariate analyses were performed to identify predictors of
worse outcome. RESULTS: During a median follow-up of 8 months, 75 patients (30%)
had treatment failure because of the occurrence of an AIDS-defining event or
death (n = 24), inefficacy (n = 24), or severe intolerance (n = 27). Twenty new
and six recurrent AIDS-defining events, and nine deaths occurred (six out of 20
AIDS-defining events and two out of nine deaths within 1 month of treatment).
CD4+ counts were above 200 x 10(6)/l at AIDS diagnosis in only two patients. None
of the SQV patients, 12 (7.8%) of the IDV patients, and 15 (27.3%) of the RTV
treated patients were considered non-compliant. The SQV-containing regimens
independently correlated with treatment failure (relative risk, 2.46; 95%
confidence interval, 1.20-5.03; versus IDV). Low compliance partially determined
outcome in RTV-treated patients; both severe immunodepression and AIDS at
baseline were predictive of treatment failure. There was a 10-fold increase in
CD4+ cell counts in the patients treated with IDV and RTV; the best virological
outcome occurred in IDV-treated patients, with 68.4% of patients showing
undetectable HIV RNA copies after 6 months. CONCLUSIONS: HAART was effective in
70% of patients; low compliance and previous AIDS diagnosis represented
predictive factors of therapy failure.
PMID- 9764783
TI - The relative prognostic value of plasma HIV RNA levels and CD4 lymphocyte counts
in advanced HIV infection.
AB - OBJECTIVE: It has been suggested that the plasma HIV RNA level is a better
predictor of AIDS and death than the CD4 lymphocyte count. We assessed whether
the prognostic value of plasma virus levels was different according to the CD4
count. DESIGN: Prospective cohort study of HIV-infected patients followed for a
median of 2.91 years (range, 0.02-4.54). SETTING: Department of Infectious
Diseases at Rigshospitalet, Copenhagen, Denmark. PARTICIPANTS: A group of 255 HIV
infected individuals with an initial measurement of CD4 lymphocyte count and
plasma HIV RNA. MAIN OUTCOME MEASURE: Survival time. RESULTS: The plasma HIV RNA
(median 101410 copies/ml; range (range 200-7200000) and the CD4 lymphocyte count
(median 250 cells x 10(6)/l; range 1-1247) were negatively correlated (Pearson r
= -0.53; P < 0.00001). Of the 255 patients, 110 died during follow-up. Overall, a
higher HIV RNA level was associated with increased risk of death, but the
association was smaller in patients with lower CD4 lymphocyte counts (test for
interaction P < 0.0001). In patients with CD4 count below 50 cells x 10(6)/l the
association between HIV RNA and risk of death was not statistically significant
(relative hazard per 10-fold higher HIV RNA level was 1.53; P = 0.11; adjusted
for age and CD4 count) while that between the CD4 count and risk of death was
highly significant (relative hazard per 50% lower CD4 count 1.38; P = 0.005;
adjusted for age and HIV RNA level). CONCLUSIONS: Patients were relatively
lightly treated with antiretroviral drugs both before and during this study. In
this situation, it appears that the HIV RNA level has a relatively weak
association with risk of death in patients with advanced HIV infection and that
the CD4 lymphocyte count is probably more useful in assessing prognosis.
PMID- 9764785
TI - Effects of vitamin E and C supplementation on oxidative stress and viral load in
HIV-infected subjects.
AB - OBJECTIVES: The HIV-infected population is known to be oxidatively stressed and
deficient in antioxidant micronutrients. Since in vitro replication of HIV is
increased with oxidative stress, this study assessed the effect of antioxidant
vitamin supplementation on lipid peroxidation, a measure of oxidative stress, and
viral load in humans. DESIGN: A randomized placebo-controlled, double-blind
study. METHODS: Forty-nine HIV-positive patients were randomized to receive
supplements of both DL-alpha-tocopherol acetate (800 IU daily) and vitamin C
(1000 mg daily), or matched placebo, for 3 months. Plasma antioxidant
micronutrient status, breath pentane output, plasma lipid peroxides,
malondialdehyde and viral load were measured at baseline and at 3 months. New or
recurrent infections for the 6-month period after study entry were also recorded.
RESULTS: The vitamin group (n = 26) had an increase in plasma concentrations of
alpha-tocopherol (P < 0.0005) and vitamin C (P < 0.005) and a reduction in lipid
peroxidation measured by breath pentane (P < 0.025), plasma lipid peroxides (P <
0.01) and malondialdehyde (P < 0.0005) when compared with controls (n = 23).
There was also a trend towards a reduction in viral load (mean +/- SD changes
over 3 months, -0.45 +/- 0.39 versus +0.50 +/- 0.40 log10 copies/ml; P = 0.1; 95%
confidence interval, -0.21 to -2.14). The number of infections reported was nine
in the vitamin group and seven in the placebo group. CONCLUSION: Supplements of
vitamin E and C reduce oxidative stress in HIV and produce a trend towards a
reduction in viral load. This is worthy of larger clinical trials, especially in
HIV-infected persons who cannot afford new combination therapies.
PMID- 9764784
TI - The effect of protease inhibitors on weight and body composition in HIV-infected
patients.
AB - OBJECTIVES: To determine the nutritional changes that occur in HIV-infected
patients receiving protease inhibitor (PI) therapy and to determine the effects
of PI treatment on physical functioning and health perceptions in patients with
HIV infection. DESIGN: Longitudinal data analysis of 38 patients from a large
Nutrition and HIV cohort. METHODS: Patients were included if they had started PI
therapy after enrollment in the cohort, if they had taken the drug for at least 4
months without interruption and if data on weight, body composition and viral
loads were available. RESULTS: Mean person-months of follow-up was 8.1 months
before and 12.2 months after PI treatment. Weight (1.54 kg, P < 0.0001), body
mass index (0.50 kg/m2, P < 0.0001), physical functioning (8.52 points, P =
0.0006) and current health perception (6.7 points, P = 0.01) increased
significantly, and the daily caloric intake increase was close to significance
(915.5 kJ/day, P = 0.06), after treatment with PI. Lean body mass did not change.
Patients who responded to PI therapy with decreased viral load (n = 28) had
significantly greater weight gain per month than non-responders. CONCLUSIONS: PI
therapy of HIV infection is associated with weight gain and improvement in
quality of life indices. The weight gain is mainly in fat mass, with no change in
lean body mass (skeletal muscle). Optimal therapy of HIV-infected patients with
weight loss may require highly active antiretroviral therapy combined with an
anabolic stimulus such as exercise, anabolic steroids or human growth hormone.
PMID- 9764786
TI - Mycobacterium xenopi in HIV-infected patients: an emerging pathogen.
AB - BACKGROUND: Mycobacterium xenopi is associated with pulmonary disease in patients
with loss of local or general host defence. OBJECTIVES: To determine the
occurrence of M. xenopi in our hospital during 1987-1992 and 1993-1996, as well
as the association of M. xenopi with HIV infection in 1993-1996; to evaluate the
clinical significance of M. xenopi in HIV-seropositive patients. DESIGN:
Retrospective review of charts and classification of patients based on earlier
definitions derived from the American Thoracic Society. SETTING: Tertiary
hospital. PATIENTS: Patients with a positive isolate of M. xenopi from January
1987 until December 1996. MAIN OUTCOME MEASURES: During 1993 1996, a significant
increase in the number of patients with M. xenopi was found compared with 1987
1992. Of 25 patients, 22 were HIV-seropositive. RESULTS: The HIV-seropositive
patients were classified as having definite (n = 5), probable (n = 9) and
unlikely disease (n = 8) due to M. xenopi. Symptoms, median CD4 cell count,
treatment and outcome did not differ between these groups. CONCLUSIONS: M. xenopi
is an emerging pathogen, especially in HIV-infected patients. The criteria of the
American Thoracic Society for disease due to non-tuberculous mycobacteria do not
seem applicable to M. xenopi in HIV-infected patients. We suggest that two
positive cultures of M. xenopi and no other likely cause of symptoms present
should be considered the criteria for diagnosis of M. xenopi disease in HIV
infected patients.
PMID- 9764787
TI - Taste and smell complaints in HIV-infected patients.
AB - OBJECTIVES: To define the scope of taste and smell (chemosensory) complaints
amongst HIV-infected persons in the study population; to evaluate the clinical
factors associated with chemosensory complaints; and to determine the impact of
chemosensory complaints on quality of life. DESIGN: Cross-sectional survey.
SETTING: Tertiary care university medical center clinic. PARTICIPANTS: A total of
207 HIV-infected patients. MAIN OUTCOME MEASURES: Chemosensory complaint score
from taste and smell questionnaire and quality of life scores from the Medical
Outcomes Study HIV Health Survey (MOS-HIV). RESULTS: A total of 144 patients
(70%) reported chemosensory complaints, 91 (44%) reported both taste and smell
complaints, 47 (23%) reported only taste complaints, and six (3%) reported only
smell complaints. Many patients complained that drugs interfered with their sense
of taste, or that medications tasted bad. Higher chemosensory complaint scores
were associated with a greater number of medications taken, tobacco use, and hay
fever. Patients with chemosensory complaints had significantly lower scores in
all domains of the MOS-HIV than those without complaints. Quality of life as
measured by the MOS-HIV was lower in patients with chemosensory complaints even
after controlling for number of AIDS diagnoses, number of medications, CD4 cell
count, and HIV-1 viral load. CONCLUSIONS: Chemosensory complaints were common in
the patient population and were associated with a poor quality of life.
Medications played an important role in chemosensory complaints. Measures to
optimize taste and smell function may improve quality of life and medication
adherence, and prevent complications such as inadequate oral intake,
malnutrition, weight loss, and ultimately wasting.
PMID- 9764788
TI - Antiretroviral drugs as a public health intervention for pregnant HIV-infected
women in rural South Africa: an issue of cost-effectiveness and capacity.
AB - OBJECTIVE: To estimate cost-effectiveness and capacity requirements for providing
antiretroviral drugs to pregnant HIV-infected women in rural South Africa.
SETTING: Hlabisa health district, where HIV prevalence among pregnant women was
26.0% in 1997. METHODS: Calculation of the number of paediatric HIV infections
averted under three scenarios, and their cost. No intervention was compared with
scenario A (zidovudine delivered within current infrastructure), scenario B
(zidovudine delivered through enhanced infrastructure), and scenario C (short
course zidovudine plus lamivudine delivered through enhanced infrastructure).
Cost-effectiveness was defined as cost per infection averted and cost per
potential life-year gained. Capacity was determined in terms of staff and
infrastructure required to effectively implement the scenarios. RESULTS: With no
intervention, 657 paediatric HIV infections were projected for 1997. In scenario
A this could be reduced by 15% at a cost of US$ 574 825, in scenario B by 42% at
US$ 1520770, and in scenario C by 47% at US$ 764901. In scenario C, drugs
accounted for 76% of costs, whereas additional staff accounted for 18%. Cost per
infection averted was US$ 2492 and cost per potential life-year gained
(discounted at 3%) was US$ 88. Cost of scenario C was equivalent to 14% of the
1997 district health budget. At least 12 extra counsellors and nurses and one
laboratory technician, together with substantial logistical and managerial
support, would be needed to deliver an effective intervention. CONCLUSION:
Although antiretrovirals may be relatively cost-effective in this setting, the
budget required is currently unaffordable. Developing the capacity required to
deliver the intervention would pose both a major challenge, and an opportunity,
to improve health services.
PMID- 9764789
TI - Pneumococcal vaccination in HIV-1-infected adults in Uganda: humoral response and
two vaccine failures.
AB - OBJECTIVES: To assess the feasibility of establishing a pneumococcal vaccine
trial among HIV-1-infected adults in Uganda and to characterize their responses
to 23-valent pneumococcal polysaccharide vaccine. DESIGN: An open-label pilot
trial to assess recruitment and compliance of HIV-1-infected adults in Uganda to
vaccination and to determine the immunogenicity of the vaccine. SETTING: A
community clinic for HIV-1-infected adults in Entebbe, Uganda. METHODS: Levels of
capsule-specific IgG to four common vaccine capsular serotypes were measured
before vaccination and 1 month after vaccination. Subsequent rates of disease
episodes and deaths, and immunologic responses in two vaccine failures, were
followed. RESULTS: One month after-vaccination, both HIV-1-infected (n = 77) and
seronegative control subjects (n = 10) demonstrated a significant rise in capsule
specific immunoglobulin G (IgG) for three of four serotypes tested, but levels
were significantly lower among HIV-1-infected patients. In 149 patient-years of
follow-up, two (2.6%) developed pneumococcal pneumonia, one bacteremic with
serotype 1 and one non-bacteremic with serotype 13, a non-vaccine serotype; both
patients showed inadequate killing of the organism in vitro. In this same follow
up period, 29 (38%) patients died. CONCLUSION: HIV-1-infected adults in Uganda
are at high risk of pneumococcal disease and show a significant but suboptimal
response to pneumococcal vaccine. Although reliable recruitment and follow-up of
vaccinees is feasible, evaluation of vaccine efficacy may be compromised by
limited responses to common vaccine serotypes, an unknown incidence of disease
with non-vaccine serotypes, and a high rate of mortality unrelated to
Streptococcus pneumoniae infection.
PMID- 9764790
TI - Effects of age at seroconversion and baseline HIV RNA level on the loss of CD4+
cells among persons with hemophilia. Multicenter Hemophilia Cohort Study.
AB - OBJECTIVE: To assess the impact of age at seroconversion and HIV RNA level in
serum during early chronic infection on the initial values and subsequent trends
(slopes) of CD4+ lymphocyte counts. DESIGN AND METHODS: In a cohort of 137 HIV-1
positive hemophiliacs with well-estimated dates of seroconversion, baseline HIV
RNA level was measured by reverse transcription PCR in serum specimens collected
12-36 months after the estimated date of seroconversion. Baseline values, 24
months after seroconversion, and slopes of CD4+ lymphocyte counts by age and HIV
RNA quartile were examined by fitting random effects models that allowed for
intrasubject variability. RESULTS: Both age at seroconversion and HIV RNA level
were associated with the CD4+ lymphocyte count at baseline and its subsequent
slope. The baseline median CD4+ lymphocyte count was 620 x 10(6)/l. Within each
HIV RNA quartile, the median CD4+ cell count of the oldest subjects (age 30-58
years) was about 200 x 10(6)/l lower and at least 350 x 10(6)/l lower than the
median counts of the younger (age 11-29 years) and youngest (age 2-10 years)
subjects, respectively. Within each age-group, the median CD4+ cell count
differed by about 200 x 10(6)/l between subjects in the lowest compared with the
highest HIV RNA quartiles. The mean slope of the CD4+ lymphocyte count after
month 24 was linear on the square-root scale, steeper in children, and did not
vary significantly by baseline HIV RNA quartile. There was large variation
between subjects that was unexplained by differences in age and HIV RNA level.
CONCLUSIONS: By 24 months after HIV seroconversion, the oldest subjects and those
with the highest HIV RNA levels during early chronic infection had experienced
the most severe depletion of CD4+ cells. Subsequent declines in CD4+ cells varied
little by early chronic HIV RNA level or age.
PMID- 9764791
TI - Bacterial vaginosis and disturbances of vaginal flora: association with increased
acquisition of HIV.
AB - BACKGROUND: Cross-sectional studies suggest an association between bacterial
vaginosis (BV) and HIV-1 infection. However, an assessment of a temporal effect
was not possible. OBJECTIVES: To determine the association of BV and other
disturbances of vaginal flora with HIV seroconversion among pregnant and
postnatal women in Malawi, Africa. DESIGN: Longitudinal follow-up of pregnant and
postpartum women. METHODS: Women attending their first antenatal care visit were
screened for HIV after counselling and obtaining informed consent. HIV
seronegative women were enrolled and followed during pregnancy and after
delivery. These women were again tested for HIV at delivery and at 6-monthly
visits postnatally. Clinical examinations and collection of laboratory specimens
(for BV and sexually transmitted diseases) were conducted at screening and at the
postnatal 6-monthly visits. The diagnosis of BV was based on clinical criteria.
Associations of BV and other risk factors with HIV seroconversion, were examined
using contingency tables and multiple logistic regression analyses on antenatal
data, and Kaplan-Meier proportional hazards analyses on postnatal data. RESULTS:
Among 1196 HIV-seronegative women who were followed antenatally for a median of
3.4 months, 27 women seroconverted by time of delivery. Postnatally, 97
seroconversions occurred among 1169 seronegative women who were followed for a
median of 2.5 years. Bacterial vaginosis was significantly associated with
antenatal HIV seroconversion (adjusted odds ratio = 3.7) and postnatal HIV
seroconversion (adjusted rate ratio = 2.3). There was a significant trend of
increased risk of HIV seroconversion with increasing severity of vaginal
disturbance among both antenatal and postnatal women. The approximate
attributable risk of BV alone was 23% for antenatal HIV seroconversions and 14%
for postnatal seroconversions. CONCLUSIONS: This prospective study suggests that
progressively greater disturbances of vaginal flora, increase HIV acquisition
during pregnancy and postnatally. The screening and treating of women with BV
could restore normal flora and reduce their susceptibility to HIV.
PMID- 9764792
TI - Declining HIV-2 prevalence and incidence among men in a community study from
Guinea-Bissau.
AB - OBJECTIVE: To assess the present level of HIV-2 infection in an adult population
in Bissau and to evaluate sex and age-specific changes in HIV-2 prevalence and
incidence between 1987 and 1996. DESIGN AND METHODS: Sex and age-specific changes
in HIV-2 prevalence were evaluated comparing a survey from 1987 in a sample of
100 houses with a survey performed in 1996 in an independent sample of 212 houses
from the same study area. HIV-2 incidence rates were examined in an adult
population (age > or = 15 years) from 100 randomly selected houses followed with
four consecutive HIV serosurveys from 1987 to 1996. RESULTS: The HIV-2 prevalence
in 1996 was 6.8% (men, 4.7%; women, 8.4%). Compared with the 1987 survey there
was a significant decrease in prevalence among men [age-adjusted relative risk
(RR), 0.50; 95% confidence interval (CI), 0.31-0.83], whereas it remained
unchanged in women (RR, 1.00; 95% CI, 0.67-1.48). The male-to-female RR decreased
from 0.99 (95% CI, 0.61-1.61) in 1987 to 0.51 (95% CI, 0.34-0.76) in 1996. The
overall annual incidence rate was 0.54 per 100 person-years of observation (PYO),
being higher in women (0.72 per 100 PYO) than in men (0.31 per 100 PYO). With the
observation time divided into an early and a late period, there was a decrease in
incidence with time among men (0.66 to 0.00 per 100 PYO), but no major change
among women (0.59 to 0.85 per 100 PYO). The two trends differed significantly (P
= 0.03). We observed a higher annual incidence rate amongst older women aged > 44
years (1.77 per 100 PYO) than among younger women (0.55 per 100 PYO; P = 0.05).
CONCLUSION: There are no signs of an epidemic spread of HIV-2 in Bissau even
though the HIV-1 prevalence is increasing rapidly. A significant reduction in the
male HIV-2 prevalence and incidence rates has resulted in a major shift in the
pattern of spread of HIV-2, from being equally distributed to being predominantly
a female infection. Currently, older women in particular seem to have a high risk
of getting infected.
PMID- 9764793
TI - Highly active antiretroviral therapy leads to a significant but delayed increase
of CD45RA+ T-helper cells.
PMID- 9764794
TI - Complete regression of AIDS-related Kaposi's sarcoma-associated human herpesvirus
8 during therapy with indinavir.
PMID- 9764795
TI - Herpes zoster infection in HIV-seropositive patients associated with highly
active antiretroviral therapy.
PMID- 9764796
TI - Progressive multifocal leukoencephalopathy following initiation of highly active
antiretroviral therapy.
PMID- 9764797
TI - Acute hepatitis in HIV-infected patients during ritonavir treatment.
PMID- 9764798
TI - Bacterial lipopolysaccharide is a potent inhibitor of HIV-1 replication in T
lymphocytes and macrophages.
PMID- 9764799
TI - Use of highly sensitive assays for the evaluation of post-exposure HIV
prophylaxis.
PMID- 9764800
TI - Performance of an ultrasensitive assay to test undetectable viral load specimens
using the branched DNA assay.
PMID- 9764801
TI - Comparison of zidovudine phosphorylation in lymph nodes and peripheral blood
mononuclear cells in HIV-infected patients. DATRI 012 Study Group.
PMID- 9764802
TI - Increased susceptibility to HIV-1 infection of peripheral blood mononuclear cells
from chronically immune-activated individuals.
PMID- 9764803
TI - Effect of natural interferon-beta on the growth of melanoma cell lines.
AB - Malignant melanoma is one of the fulminant skin cancers. The 5-year survival of
patients with stage III (N0, N1) malignant melanoma treated with multi-agent
chemoimmunotherapy, including natural interferon-beta (nIFNbeta), was found in
our department to be better than that of patients treated with other forms of
therapy. In order to study the effects of nIFNbeta on melanoma, the growth
inhibition effect of nIFNbeta was assessed in vitro using the melanoma cell
lines, MM8.1, MM28, MM33.1, Bowes and A375-2. The growth of these cell lines was
inhibited by nIFNbeta. Incorporation of [3H]thymidine and [3H]uridine was also
inhibited by nIFNbeta in a dose-dependent manner. Apoptosis was demonstrated
using the TUNEL method in melanoma cell lines cocultured with nIFNbeta. Results
showed that nIFNbeta had direct killer activity on melanoma cell lines.
PMID- 9764804
TI - The PTEN tumour suppressor gene and malignant melanoma.
AB - A candidate tumour suppressor gene, PTEN, has recently been identified within
chromosome 10q23, the locus of the Cowden syndrome/Lhermitte Duclos disease
susceptibility gene. Cowden disease is an autosomal dominant cancer
predisposition syndrome associated with tumours of the breast, thyroid and, less
frequently, malignant melanoma. Based on the identification of mutations in
sporadic breast, brain and prostate tumours, we decided to examine the potential
role of PTEN in sporadic malignant melanoma. Frozen tissue from primary cutaneous
melanomas (n = 23) and metastases (n = 17) were microdissected, and
microsatellite markers D10S541 and D10S547, flanking the gene on both sides, were
used to search for loss of heterozygosity (LOH) in the PTEN gene locus. To
identify mutations within the putative tumour suppressor gene, we performed
single strand conformation polymorphism (SSCP) analysis using intronic primers to
amplify exons 5, 6, 7 and 8 of the PTEN gene. No LOH was detected using the
polymorphic markers D10S541 and D10S547. SSCP analysis revealed no aberrant bands
in the tumour specimen. Our results suggest that the PTEN gene does not play a
major role in the initiation and progression of melanoma.
PMID- 9764805
TI - Positive association between cytoskeletal changes, melanoma cell attachment and
invasion in vitro.
AB - The literature concerning cytoskeletal changes and metastatic progression is
unresolved, some studies suggesting a positive association between the ability of
cells to organize their cytoskeleton and others suggesting an inverse
correlation. In an attempt to learn more about cytoskeletal changes and the
ability of melanoma cells to interact with extracellular matrix proteins we
examined the effects of pharmacological manipulation of cell attachment and cell
invasion through fibronectin on levels of F-actin and vimentin in a highly
metastatic cutaneous melanoma cell line (A375-SM cells). Additionally, we
examined whether any correlation existed between the levels of the cytoskeletal
proteins and subpopulations of the cell line of varying invasive ability. We
report that agents which reduced cell attachment to plastic and invasion through
fibronectin in vitro (tamoxifen, N-desmethyltamoxifen and 17beta-oestradiol)
caused increases in levels of F-actin and vimentin, whereas agents which did not
affect attachment or invasion (4-hydroxytamoxifen and dihydrotestosterone) had
little or no effect on the cytoskeletal proteins. In contrast, however, those
cells which were most effective at invading through fibronectin were
significantly better at acutely increasing their levels of F-actin and vimentin
than less invasive cells. We speculate that the ability to rapidly and possibly
reversibly alter the cytoskeleton might be associated with metastatically
successful cells in vivo.
PMID- 9764806
TI - Sensitivity of human melanoma cells to oestrogens, tamoxifen and quercetin: is
there any relationship with type I and II oestrogen binding site expression?
AB - We investigated the effect of oestrogens, anti-oestrogens and flavonoids on the
growth of a human melanoma cell line (SK-Mel-28) and, at the same time, the
presence of both type I oestrogen receptors (ERs) and type II oestrogen binding
sites (type II EBS) to gain a fuller picture of the relationship between melanoma
cell proliferation and receptor status. 17beta-Oestradiol (E2) and the flavonoid
quercetin (Q) produced a marked inhibition of proliferation, but only at the
highest dose used (10(-5) M) and only when added daily to the medium.
Diethylstilboestrol (DES) (10(-5) M) was effective in inhibiting cell growth when
the medium was renewed every 3 days and produced a more pronounced reduction when
added daily to the medium. Tamoxifen (TAM) inhibited cell proliferation at a dose
starting from 10(-7) M when the medium was renewed every 3 days. When added daily
to the medium, it did not induce a greater inhibitory effect and it was cytotoxic
at 5 x 10(-6) M and 10(-5) M. The antiproliferative effect of E2, DES and Q did
not seem to be dependent on their interaction with ERs, which were minimally
detected in SK-Mel-28 in both immunocytochemical and biochemical assays. Our
model revealed, through a biochemical assay, a large number of type II EBSs which
could be involved in the anti-oestrogen action, but this does not exclude the
involvement of other mechanisms. Finally, TAM (10(-5) M) appeared to reduce the
activity of the DNA repair enzyme O6-alkylguanine-DNA alkyltransferase, an effect
that could be interesting from the point of view of the therapeutic efficacy of
alkylating agents.
PMID- 9764807
TI - Effect of prostaglandin A1 on proliferation and telomerase activity of human
melanoma cells in vitro.
AB - Previous studies have shown that cyclopentenone prostaglandins are endowed with
antitumour activity in various murine and human tumour models. In the present
investigation four human melanoma cell lines were treated with graded
concentrations (4-16microg/ml) of prostaglandin A1 (PGA1) for 24 or 48 h in
vitro. At the end of the treatment, cell proliferation (measured in terms of DNA
synthesis) and telomerase activity were determined. The results showed that PGA1
induced concentration-dependent inhibition of DNA synthesis at 48 h but not at 24
h in SK-MEL-28 cells. In contrast, marked inhibition of telomerase activity was
detected after only 24 h of PGA1 treatment. Moreover, after 48h of treatment with
the agent, inhibition of telomerase was more pronounced than inhibition of cell
proliferation. Additional studies performed with three freshly generated melanoma
cell lines confirmed that PGA1 produced early inhibition of cell growth
accompanied by marked impairment of telomerase activity. These results suggest
that PGA1 could be of potential value as antitumour agent, on the basis of two
distinct mechanisms: direct cytostatic/cytotoxic effects on melanoma cells, and
inhibitory activity on a tumour-associated enzymatic function (i.e. telomerase)
that is responsible for cancer cell immortality.
PMID- 9764808
TI - Modifications of the antioxidant enzymes in relation to chromosome imbalances in
human melanoma cell lines.
AB - Five human melanoma cell lines were investigated for their antioxidant
activities. These metabolic data were correlated with cytogenetic analysis giving
the relative numbers of chromosomes or chromosomal segments carrying the gene
encoding for each enzyme. Particular attention was focused on the expression of
superoxide dismutase 2 (SOD2), whose gene, located on the long arm of chromosome
6 (6q), has been proposed as a tumour suppressor gene. The activity of
glutathione peroxidase (GPX), glutathione reductase (GSR) and catalase appeared
to be unrelated to the relative number of 3q, 8p and 11p arms which,
respectively, carry their encoding genes. GPX activity paralleled that of total
SOD activity, and GSR variations followed those of GPX, suggesting possible
metabolic regulation. Both the activity and the amount of SOD1 immunoreactive
protein correlated with the number of chromosomes 21, suggesting a gene dosage
effect. The three cell lines with deletions of the 6q arm had lower SOD2 activity
and less immunoreactive protein than the two cell lines without 6q deletion. In
addition, they demonstrated high thymidine kinase and thymidylate synthetase
activities, which are directly linked to the cell proliferation rate. These
results strengthen the hypothesis that SOD2 has a function as a tumour suppressor
gene, but also suggest that the expression of other antioxidant enzymes might be
altered in human melanomas.
PMID- 9764809
TI - Melan A/MART-1 immunoreactivity in formalin-fixed paraffin-embedded primary and
metastatic melanoma: frequency and distribution.
AB - Monoclonal antibody (MAb) A103 specifically detects Melan A/MART-1 protein
expression. Melan A/MART-1-derived peptides are recognized by CD8+ T-cells and
are used in immunotherapy. We examined formalin-fixed paraffin-embedded tissue
from 57 melanomas (34 primary, 23 metastatic) and 39 control cases (junctional,
dermal, compound, Spitz, Reed and balloon-cell naevi) using the alkaline
phosphatase and anti-alkaline phosphatase immunochemical method after antigen
retrieval. Immunoreactivity was rated as low, medium or high, and staining
pattern as homogeneous or heterogeneous. Staining with MAb A103 showed a
sensitivity of 88% for melanoma, with a very high specificity for melanocytic
cells. Immunopositivity decreased along with clinical stage, with stage I showing
100%, stage II 88%, stage III 90% and stage IV 75% immunoreactivity. Staining
changed from an exclusively homogeneous pattern in the early clinical stages to a
more heterogeneous pattern in the later stages. Melanocytic control tissues
consisting of naevi of different subtypes all showed weak to moderate homogeneous
immunoreactivity, with polarity towards the epidermis. Analysis of short-term
melanoma cell cultures using reverse transcription-polymerase chain reaction (RT
PCR) enzyme-linked immunosorbent assay (ELISA) demonstrated mRNA expression in
only one third of the originally immunopositive tumours, suggesting rapid mRNA
expression loss in culture. MAb A103 allows the detection of melanoma-associated
Melan A/MART-1 protein expression in routine archival tissue and thus enables the
profiling of melanomas suited for immunotherapy approaches involving Melan A/MART
1 derived epitopes.
PMID- 9764810
TI - TAP prefers to transport melanoma antigenic peptides which are longer than the
optimal T-cell epitope: evidence for further processing in the endoplasmic
reticulum.
AB - Many melanoma epitopes are presented to cytotoxic T-lymphocytes (CTLs) by major
histocompatibility complex (MHC) class I molecules, and it is reasonable to
expect that the epitopes would be good substrates for the transporter associated
with antigen processing (TAP), as TAP plays a major role in the transport of
peptides into the endoplasmic reticulum (ER) for binding to MHC class I
molecules. However, we have previously shown that several melanoma-associated
epitopes, such as those derived from tyrosinase, gp100, MAGE-1 and MAGE-2
antigens, are in fact poor substrates for TAP. During the process of determining
why these epitopes were capable of eliciting a strong CTL response, yet were poor
substrates for TAP, it was observed that the epitopes possessed amino acids at
their N-terminus that were deleterious for TAP binding as described for the
peptide-binding motif for human TAP. We therefore postulated that the epitopes
were transported by TAP as longer precursor molecules, and then trimmed in the ER
to the appropriate size for presentation to T-cells. In an effort to test this
hypothesis we synthesized a set of peptides, derived from the tyrosinase
(YMNGTMSQV) and MAGE-1 (EADPTGHSY) epitopes, which possess N-terminal extensions
of up to four amino acids. We show here that the longer peptides are indeed
transported into the ER at a significantly higher level than the original
epitopes. The data indicate that the longer melanoma-associated peptides are the
preferred substrates for TAP, and further support the notion that peptides can be
trimmed at the N-terminus in the ER during antigen processing.
PMID- 9764811
TI - Detection of recurrent malignant melanoma with 99mTc-MIBI scintigraphy.
AB - Initial reports suggest that 99mTc-methoxyisobutylisonitrile (MIBI) scanning may
be of clinical value in staging patients with malignant melanoma. We carried out
a study to evaluate the potential of this technique in the detection of recurrent
disease. Whole-body 99mTC-MIBI scans were performed in 81 patients with a history
of a surgically excised MM: 28 with known recurrent lesions and 53 during follow
up without evidence of disease. Images started 10 min post-injection, using a
dose of 740 MBq. Diagnoses were confirmed by cytological/histological examination
or at least one conventional imaging modality. Blinded interpretations of the
MIBI scans were performed. Whole-body MIBI scanning correctly detected 68 (92%)
of 74 metastatic lesions in the following sites: regional lymph nodes (n=23), non
regional lymph nodes (n=10), skin (n=16), brain/cerebellum (n=6), lung (n=8),
bone (n=4) and breast (n=1). The technique failed to detect three subcutaneous
regressive lesions (< 1 cm), one liver metastasis, one spleen metastasis and a
case of multiple small lesions of the duodenal mucous membrane. In 14 patients
the procedure detected previously unknown metastatic lesions. These results
suggest that 99mTc-MIBI scanning is an effective imaging modality for whole-body
screening of metastatic disease in malignant melanoma patients with the potential
to influence treatment planning.
PMID- 9764812
TI - Multiple primary melanomas: analysis of 49 cases.
AB - Development of multiple primary melanomas is a rare but well recognized disease,
with an estimated incidence ranging from 1.75% to 8.5% in several series. The
clinical, histological and epidemiological characteristics of 49 patients,
identified from 2470 with histologically confirmed melanoma, are described in
this study. Thirty-five of these patients had two primary melanomas, 11 had three
melanomas and three had four, five and six melanomas, respectively. Diagnosis was
concurrent in 22 patients (45%); in the remaining cases the median time interval
between the first and second melanoma was 22.6 months and the longest interval
was 21.5 years. The mean Breslow's thickness decreased significantly (P < 0.001)
from the first melanoma to the second and third lesion. The multiple melanoma
patients had a higher percentage of subjects over 70 years of age or with lentigo
maligna melanoma than single melanoma patients. The mean follow-up time was 12
years (range 4 23 years). The 5-year survival rate from first melanoma excision
(83%) does not differ from that of patients with a single melanoma. In
conclusion, the presence of multiple primary melanomas does not appear to be a
negative prognostic factor; our data show the importance of close follow-up in
melanoma patients in order to detect not only metastases, but also subsequent
primaries in their earliest phases.
PMID- 9764813
TI - Syndrome of inappropriate secretion of antidiuretic hormone in a patient affected
by metastatic melanoma.
AB - The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is
characterized by hyponatraemia due to water retention resulting from the
persistent release of antidiuretic hormone (vasopressin). It may occur in a
variety of malignant and non-malignant conditions, in particular in association
with oat cell carcinoma, pulmonary and cerebral diseases. We report the case of a
male patient affected by melanoma of the right temporal region with brain
metastasis who developed acute headache, drowsiness, nausea, vomiting and
pathological reflexes. Clinical and laboratory investigations led us to the
diagnosis of SIADH. Restriction of fluid intake obtained a good clinical
improvement with normalization of laboratory alterations; after 2 months the
patient experienced a new episode of SIADH which was promptly treated. As
melanoma has been occasionally observed in association with SIADH it should be
included in the list of tumours that can cause this particular syndrome.
PMID- 9764814
TI - Phenotypic markers, sunlight-related factors and sunscreen use in patients with
cutaneous melanoma: an Austrian case-control study.
AB - Sunscreens have been advocated to prevent burning in the hope that this will
decrease the chance of developing melanoma. In a single-centre case-control study
in Styria, Austria, we examined the risk of cutaneous malignant melanoma in
relation to phenotypic markers, sunlight-related factors and sunscreen use. In
total, 193 melanoma patients and 319 control subjects answered a comprehensive
questionnaire regarding phenotypic markers, a variety of sunlight-related factors
and sunscreen use. Risk factors for melanoma were examined through the use of
unconditional logistic regression analysis, controlling for age and sex.
Screening for confounding factors was done by forward and backward elimination of
non-significant variables (P < 0.05). The resulting set of factors were
investigated further for effect modification by introducing interactions into the
model. The factor most significantly associated with increased melanoma risk was
the use of sunscreens. Subjects who often used sunscreens had an increased odds
ratio (OR) of 3.47 (95% confidence interval [CI]1.81-6.64) compared with subjects
who never used sunscreens (P = 0.001), after adjustment for sex, age and other
significant sunlight-related factors. Skin colour and higher numbers of sunbaths
were significant protective factors. Subjects with medium skin colour had an
adjusted OR of 0.63 (95% CI 0.41-0.99) compared with subjects with light skin
colour (P = 0.0022). Subjects who took more than 30 sunbaths per year and
subjects who took 20-30 sunbaths per year had, in the absence of sunburn(s), a
decreased OR of 0.09 (95% CI 0.02-0.39) and 0.28 (95% CI 0.13-0.64),
respectively, compared with subjects who took less than 20 sunbaths per year (P =
0.0002). However, sunbaths had no protective value when they were associated with
sunburns. Although we cannot exclude the presence of an unknown confounding
factor, our results suggest that the use of sunscreens does not help prevent
melanoma.
PMID- 9764815
TI - Effective combined immunochemotherapy with dinitrochlorobenzene and fotemustine
in skin and brain metastases of melanoma.
PMID- 9764816
TI - Cancer phenotype correlates with constitutional TP53 genotype in families with
the Li-Fraumeni syndrome.
AB - The Li-Fraumeni cancer predisposition syndrome is associated with germline TP53
mutations in the majority of families. We have investigated cancer incidence in
34 Li-Fraumeni families, according to their constitutional TP53 mutation status.
Families with germline missense mutations in the core DNA binding domain showed a
more highly penetrant cancer phenotype than families with other TP53 mutations or
no mutation. Cancer phenotype in families carrying such mutations was
characterized by a higher cancer incidence and earlier ages at diagnosis,
especially of breast cancer and brain tumours, compared with families carrying
protein truncating or other inactivating mutations (P=0.03 for all cancers,
P=0.006 for breast cancers, P=0.05 for brain tumours). Proband cancers showed
significantly younger ages at diagnosis in those with missense mutations in the
DNA binding domain than in those with protein inactivating mutations (P=0.031).
In individuals with the former type of mutation, there was a significantly lower
proportion of tumours which showed loss of the wild-type TP53 allele (P=0.004).
These results are consistent with observations in experimental systems which
demonstrate that certain mutations exhibit gain of function and/or dominant
negative properties. Our results support an enhanced oncogenic potential for such
mutations in human populations.
PMID- 9764817
TI - Bax cleavage is mediated by calpain during drug-induced apoptosis.
AB - The anti-apoptotic molecule Bcl-2 is located in the mitochondrial and endoplasmic
reticulum membranes as well as the nuclear envelope. Although its location has
not been as rigorously defined, the pro-apoptotic molecule Bax appears to be
mainly a cytosolic protein which translocates to the mitochondria upon induction
of apoptosis. Here we identify a protease activity in mitochondria-enriched
membrane fractions from HL-60 cells capable of cleaving Bax which is absent from
the cytosolic fraction. Bax protease activity is blocked in vitro by cysteine
protease inhibitors including E-64 which distinguishes it from all known caspases
and granzyme B, both of which are involved in apoptosis. Protease activity is
also blocked by inhibitors against the calcium-activated neutral cysteine
endopeptidase calpain. Partial purification of the Bax protease activity from HL
60 cell membrane fractions by column chromatography revealed that a calpain-like
activity was the protease responsible for Bax cleavage. In addition, purified
calpain enzymes cleaved Bax in a calcium-dependent manner. Pretreatment of HL-60
cells with the specific calpain inhibitor calpeptin effectively blocked both drug
induced Bax cleavage and calpain activation, but not PARP cleavage or cell death.
These results suggest that calpains and caspases are activated during drug
induced apoptosis and that calpains, along with caspases, may be involved in
modulating cell death by acting selectively on cellular substrates.
PMID- 9764818
TI - Grb2 binding to the different isoforms of Ret tyrosine kinase.
AB - The RET proto-oncogene encodes two isoforms of a receptor tyrosine kinase which
plays a role in neural crest and kidney development. Ret ligands have been
recently identified as the neuron survival factor GDNF (Glial-Derived
Neurotrophic Factor) and Neurturin. Somatic rearrangements of RET, designated
RET/PTCs, have been frequently detected in papillary thyroid carcinomas. In
addition, distinct germ-line mutations of RET gene have been associated with the
inherited cancer syndromes MEN (Multiple Endocrine Neoplasia) 2A, 2B and FMTC
(Familial Medullar Thyroid Carcinomas) as well as with the congenital megacolon
or Hirschsprung's disease, thus enlightening a significant role of this receptor
gene in diverse human pathologic conditions. In this study, by performing
classical inhibition experiments using synthetic phosphopeptides and by site
directed mutagenesis of the putative docking site, we have determined that for
Grb2 the latter is provided by the tyrosine 620 of Ret/ptc2 long isoform
(corresponding to Tyr 1096 on proto-Ret). However, in intact cells, the
interaction of Grb2 with the two short and long Ret isoforms expressed separately
is of similar strength, thus suggesting that Ret short isoform interaction with
Grb2 could be mediated not only by Shc but also by a molecule that binds
preferentially to this isoform. This possibility is supported by the evidence
that the mutant Ret/ptc2Y620F long isoform displays a weak coimmunoprecipitation
with Grb2 and that this mutant, lacking the docking site for Grb2 but owing all
the others phosphotyrosines, surprisingly displays a reduced transforming
activity compared to that of the two WTs oncogenes. We thus conclude that in
intact cells both Ret isoforms bind to Grb2, although with different modalities.
In addition, the present results are in agreement with the possibility that
different signal transduction pathways are associated with the two isoforms of
Ret.
PMID- 9764819
TI - Stress-induced secretion of growth inhibitors: a novel tumor suppressor function
of p53.
AB - p53 tumor suppressor gene controls cell response to a variety of stresses
inducing growth arrest or apoptosis in damaged cells. It largely determines the
sensitivity of tumor and normal cells to radiation and chemotherapy, and,
therefore, defines both the efficacy and limitations of anti-cancer treatment. To
determine molecular mechanisms of p53-dependent stress response in normal tissues
we identified and compared the spectra of radiation-responsive genes in cells of
different origin and p53 status using a cDNA array hybridization technique. The
majority of genes identified were p53-dependent and cell type specific. Several
of the new p53 responders encode known secreted growth inhibitory factors. This
suggests that p53, in addition to its intrinsic antiproliferation activity, can
cause 'bystander effect' by inducing export of growth suppressive stimuli from
damaged cells to neighboring cells. Consistently, a p53-dependent accumulation of
factors, which causes growth inhibitory effects in a variety of cell lines, was
found after gamma irradiation in the media from established and primary cell
cultures and in the urine of irradiated mice. Moreover, p53-dependent factors
released by normal human fibroblasts potentiated the cytotoxic effect of a
chemotherapeutic drug on co-cultivated tumor cells. This suggests a previously
unknown role for normal cells in chemo- and radiation therapy of cancer.
PMID- 9764820
TI - The Tek/Tie2 receptor signals through a novel Dok-related docking protein, Dok-R.
AB - Tek/Tie2 is an endothelial cell-specific receptor tyrosine kinase that has been
shown to play a role in vascular development of the mouse. Targeted mutagenesis
of both Tek and its agonistic ligand, Angiopoietin-1, result in embryonic
lethality, demonstrating that the signal transduction pathway(s) mediated by this
receptor are crucial for normal embryonic development. In an attempt to identify
downstream signaling partners of the Tek receptor, we have used the yeast two
hybrid system to identify phosphotyrosine-dependent interactions. Using this
approach, we have identified a novel docking molecule called Dok-R, which has
sequence and structural homology to p62dok and IRS-3. Mapping of the
phosphotyrosine-interaction domain within Dok-R shows that Dok-R interacts with
Tek through a PTB domain. Dok-R is coexpressed with Tek in a number of
endothelial cell lines. We show that coexpression of Dok-R with activated Tek
results in tyrosine phosphorylation of Dok-R and that rasGAP and Nck
coimmunoprecipitate with phosphorylated Dok-R. Furthermore, Dok-R is
constitutively bound to Crk presumably through the proline rich tail of Dok-R.
The cloning of Dok-R represents the first downstream substrate of the activated
Tek receptor, and suggests that Tek can signal through a multitude of pathways.
PMID- 9764821
TI - The C. elegans MDL-1 and MXL-1 proteins can functionally substitute for
vertebrate MAD and MAX.
AB - The genes of the myc/max/mad family play an important role in controlling cell
proliferation and differentiation. We have identified the first homologues of the
mad and max genes in the nematode C. elegans, which we have named mdl-1 and mxl-1
respectively. Like the vertebrate MAD proteins, MDL-1 binds an E-box DNA sequence
(CACGTG) when dimerized with MXL-1. However, unlike vertebrate MAX, MXL-1 can not
form homodimers and bind to DNA alone. Promoter fusions to a GFP reporter suggest
that these genes are coexpressed in posterior intestinal and post-mitotic
neuronal cells during larval development. The coexpression in the posterior
intestinal cells occurs before their final division at the end of the L1 stage
and persists afterwards, demonstrating that mad and max expression can be
correlated directly to the cell cycle state of an individual cell type. These
data also show that mxl-1 is an obligate partner for mdl-1 in vivo and in vitro
and indicate that these genes may play an important role in post-embryonic
development. Finally, MDL-1 can suppress activated c-MYC/RAS-induced focus
formation in a rat embryo fibroblast transformation assay. Like the vertebrate
MAD protein, MDL-1 activity in suppressing transformation is dependent on a
functional SIN3 interaction domain.
PMID- 9764822
TI - Endogenous p53 regulation and function in early stage Friend virus-induced tumor
progression differs from that following DNA damage.
AB - Erythroleukemia induced by the anemia strain of Friend virus occurs in two
stages. The first stage results in rapid expansion of pre-leukemic
proerythroblasts (FVA cells) dependent on erythropoietin (Epo) for
differentiation and survival in vitro. The second stage is characterized by
emergence of erythroleukemic clones (MEL cells) which typically bear activation
of the ets-oncogene, PU.1/spi.1, and loss of functional p53. We developed a
Friend virus-sensitive, p53-deficient mouse model to investigate the biological
advantage conferred by p53-loss during tumor progression. Here we report p53 was
not required for cell survival or growth arrest during differentiation of FVA
cells, nor was p53 required for induction of apoptosis upon Epo withdrawal.
However, we detected induction of the p21Cip1 cyclin-dependent kinase inhibitor
gene during differentiation, which was markedly enhanced in the presence of p53.
p53-dependent expression of p21Cip1 occurred in the absence of an increase in p53
mRNA and protein levels and was specific for p21Cip1, since expression of gadd45,
mdm-2, cyclin G and bax were unaffected by p53. In contrast, treatment of FVA
cells with DNA damaging agents led to rapid accumulation of p53 protein resulting
in transcription of multiple p53-regulated genes, leading to either apoptosis or
growth arrest, depending on the agent used. These data demonstrate that p53
dependent activities during differentiation of preleukemic erythroblasts are
distinct from those observed in response to genotoxic agents. We propose that
enhancement of p53-dependent gene expression during differentiation may represent
a tumor suppressor function which is necessary to monitor differentiation of
preleukemic cells and which is selected against during tumor progression.
PMID- 9764823
TI - Overexpression of fra-2 in transgenic mice perturbs normal eye development.
AB - The major components of transcription factor AP-1 (Activator Protein 1) are
encoded by the two families of genes related to the proto-oncogenes c-fos and c
jun. The fos-related antigen-2 (fra-2) gene is the most recently described member
of the Fos family. To determine the oncogenic potential of fra-2, transgenic mice
were generated which over-express fra-2 in a number of tissues. No tumours were
evident in any transgenic mice up to 18 months of age, although eye development
was severely disrupted in these animals. Corneal abnormalities could be observed
histologically as early as embryonic day 15.5 and eyelid fusion failed to occur.
Adult eyes were characterized by generalized anterior segment dysgenesis similar
to that previously reported in transgenic mice over-expressing transforming
growth factor alpha (TGF alpha), and occasionally microphthalmia. Expression of
fra-2 was shown to increase following TGF alpha treatment of cells in vitro,
suggesting that AP-1 complexes containing Fra-2 contribute to TGF alpha
signalling events.
PMID- 9764824
TI - TSG101 is not mutated in lung cancer but a shortened transcript is frequently
expressed in small cell lung cancer.
AB - TSG101 is a candidate tumor suppressor gene whose deletion in NIH3T3 cells leads
to spontaneous lung metastases in nude mice. Aberrant transcripts of TSG101 have
been identified in 47% of primary breast carcinomas, without evidence of
intragenic deletions at the TSG101 locus on 11p15. To investigate the possible
role of TSG101 in lung cancer, which often shows 11p allele loss, we performed
transcript analysis and mutational analysis of TSG101 in lung cancer cell lines.
Reverse transcriptase RT-PCR and Northern analysis detected a common TSG101
transcript, shortened because of an internal deletion, which was expressed
simultaneously with the wild-type transcript in 89% of small cell lung cancer
(SCLC) lines. In contrast, the wild-type transcript was expressed alone in normal
tissues, primary non-small cell lung cancer (NSCLC) specimens, and the majority
of NSCLC cell lines. Sequence of the shortened SCLC transcript was identical to
that of the most common aberrant transcript identified in breast cancer,
consisting of a deletion of exons 2-4 and part of 1 and 5. Southern analysis of
SCLC lines expressing the shortened transcript did not detect any intragenic
deletions. Single strand conformational polymorphism (SSCP) analysis and direct
sequencing of TSG101 cDNAs also identified no mutations or deletions. These
results suggest that TSG101 is not mutated in lung cancer but that aberrant
splicing of TSG101 occurs in SCLC.
PMID- 9764825
TI - Fli-1b is generated by usage of differential splicing and alternative promoter.
AB - The proto-oncogene Fli-1, a member of Ets family is rearranged or activated
through proviral integration in erythroleukemias, induced by Friends' Murine
Leukemia Virus. The DNA binding domain (ETS domain) of Fli-1 is fused to the RNA
binding domain of EWS by t(11q24:22q12) chromosomal translocation in Ewing's
sarcoma and primitive neuroectodermal tumors. Screening of human cDNA libraries
has identified two different 5'-termini and alternatively spliced forms of the
human Fli-1 gene (Fli-1b), suggesting the possible existence of two independent
promoters. The genomic sequence adjacent to the alternate exon of human Fli-1b
gene shows functional promoter activity when cloned in promoter-less CAT
expression vector and transfected into QT-6 cells. The transcription initiation
(CAP) site and minimum promoter region necessary for function were localized. The
5'-flanking regions of human Fli-1b and mouse Fli-1 show 80% homology suggesting
conserved promoter regulatory elements. The Fli-1b 5'-flanking sequence lacks
canonical TATA or CCAAT boxes but contains a partially conserved TATA-like
sequence at position 242. Several transcription factor binding sequences like
ATF/CREB, E2A-PBX1, EBP, PEA-3, ETS-2, Sp-1, c-Myc, TBP, GATA-1 and Oct-3 were
conserved in the promoter sequence. Functional promoter assays revealed that Fli
1b promoter shows very strong transcriptional activation compared to Fli-1
promoter. We also showed that variant Fli-1b has transcriptional activation
properties similar to those of Fli-1. Fli-1b and Fli-1 show differential
expression in various hematopoietic cell lines. This differential expression and
promoter activities of Fli-1 and Fli-1b suggests that several mechanisms are
involved in Fli-1 gene regulation which are mediated by many transcription
factors.
PMID- 9764826
TI - Early G1 growth arrest of hybridoma B cells by DMSO involves cyclin D2 inhibition
and p21[CIP1] induction.
AB - Dimethylsulfoxide (DMSO) was shown to inhibit the proliferation of several B cell
lines including Raji, Daudi, and SKW6-CL4 but the mechanisms involved in this
growth arrest are still unclear. We show that in 7TD1 mouse hybridoma cells a
DMSO-induced reversible G1 arrest involves inactivation of Rb kinases, cyclin
D2/CDK4 and cyclin E/CDK2. This occurs by at least three distinct mechanisms.
Inhibition of cyclin D2 neosynthesis leads to a dramatic decrease of
cyclinD2/CDK4 complexes. This in turn enables the redistribution of p27[KIP1]
from cyclin D2/CDK4 to cyclin E/CDK2 complexes. In addition, the simultaneous
accumulation of p21[CIP1] entails increasing association with cyclin D3/CDK4 and
cyclin E/CDK2. Thus, p21[CIP1] and p27[KIP1], act in concert to inhibit cyclin
E/CDK2 activity which, together with CDK4 inactivation, confers a G1-phase
arrest.
PMID- 9764827
TI - PTCH gene mutations in invasive transitional cell carcinoma of the bladder.
AB - LOH analysis suggests that multiple tumor suppressor genes play a role in the
development of human TCC. The human homolog of the Drosophila PTCH was recently
cloned and mapped to the BCNS locus on 9q22.3, a chromosomal region commonly
deleted in TCCs. We first examined the steady state mRNA transcription of the
PTCH, SMOH and GLI3 genes of the HH signal transduction pathway in TCC cell lines
and normal urothelium. Normal urothelium and TCC cell lines express these three
genes within the PTCH signal transduction pathway. We then screened for PTCH
mutations in 'hot spot' exons 6, 8, 13 and 16 by PCR/SSCP analysis of genomic
DNAs from 54 TCC tumor samples and control autologous peripheral blood
lymphocytes. DNA sequence analysis confirmed TCC-specific mutations in two of 54
patients (3.7%). These mutations resulted a single amino acid substitution and
two frame shifts. One tumor had PTCH mutations in exon 16 as well as exon 13 and
one tumor had a mutation in exon 13 alone. Both TCC tumors that contained PTCH
mutations had a loss of heterozygosity at 9q. Although the PTCH protein has an
unknown function in urothelial cells, the detection of the PTCH, SMOH and GLI3
transcripts in normal urothelium and TCC cell lines and rare PTCH mutations in
tumor samples suggest that the HH pathway may have a role in controlling the
proliferation of urothelial cells and that PTCH mutations may contribute to the
development of a subset of TCCs.
PMID- 9764828
TI - p96, a MAPK-related protein, is consistently downregulated during mouse mammary
carcinogenesis.
AB - Differential display PCR [DD-PCR] was applied to identify mRNAs differentially
expressed between two consecutive stages of an in vivo model of mouse mammary
carcinogenesis. The extended life 12 [EL12] and transformed mammary 12 [TM12]
outgrowths differ in morphology, ovarian hormone dependence, and tumorigenicity,
yet the TM12 outgrowth arose spontaneously from the EL12 outgrowth. A fragment of
the mouse p96 gene was identified using DD-PCR. The differential expression of
p96 was confirmed using RNase protection assays. Examination of the RNA
expression patterns of the p96 isoforms during normal mammary gland development
showed high levels in the involuting mammary gland and in preneoplastic
hyperplasias. In contrast, p96 isoform mRNA levels were consistently decreased in
mammary tumors derived from the in vivo hyperplasias. Examination of p96 protein
levels revealed a decrease in p96 protein in a number of mammary tumors as
compared to their hyperplastic precursors further supporting the observations
that p96 gene expression is consistently downregulated in mammary tumors. The
functional activity of p96 protein has not been resolved, however the observation
that p96 gene expression is downregulated in two different tumor systems (human
ovarian tumors and mouse mammary tumors) warrants more extensive investigation on
its role in normal and neoplastic cell growth.
PMID- 9764829
TI - Decreased fibronectin expression in Met/HGF-mediated tumorigenesis.
AB - The tyrosine kinase receptor Met and its ligand, hepatocyte growth factor
(HGF)/scatter factor are involved in the etiology and progression of a number of
human cancers. Coexpression of Met and HGF in mesenchymal cells increases the
tumorigenic and metastatic potential of the cells. In the studies described here,
we used differential display screening to identify changes in gene expression
that are initiated by Met/HGF, and that may lead to these phenotypes. We learned
that Met/HGF signaling resulted in greatly decreased fibronectin mRNA production
in three different human and mouse tumor cell lines; these decreases in
fibronectin mRNA were paralleled by decreases in fibronectin protein. We also
found a progressive decrease in fibronectin in tumor explants and metastases
derived from the Met/HGF transformed cells. The absence of fibronectin expression
is a frequent cancer phenotype; our results indicate that decreases in
fibronectin correlate with, but are not essential for, MetHGF/SF-mediated
tumorigenesis.
PMID- 9764830
TI - Frequent loss of heterozygosity and three critical regions on the short arm of
chromosome 8 in ovarian adenocarcinomas.
AB - Many chromosomal regions undergo loss of heterozygosity (LOH) in ovarian
adenocarcinomas but few of the target regions have been finely mapped. One of the
chromosome arms likely to harbour one or more tumour suppressor genes inactivated
in ovarian cancer is the short arm of chromosome 8 which is frequently deleted in
many other solid tumours. We have examined a large panel of microsatellite
markers on 8p for LOH in 53 ovarian adenocarcinomas. LOH was observed in 27
tumours (51%), with a significant trend towards a higher frequency of LOH in more
advanced tumours. Detailed examination of nine tumours with partial deletions
defined three regions of overlap, two in 8p23 and one in 8p22, which suggests
that there might be as many as three tumour or metastasis suppressor genes on 8p
which are inactivated during ovarian tumorigenesis. LOH on 8p was significantly
associated with 9p LOH which suggests that inactivation of target genes on these
chromosomes may be cooperative events.
PMID- 9764831
TI - Pterins in human hair follicle cells and in the synchronized murine hair cycle.
AB - Human dermal papilla cells (HDPC) express mRNA for the key enzymes for de novo
synthesis/recycling and regulation of the pterin (6R)-L-erythro-5,6,7,8
tetrahydrobiopterin (6BH4). HDPC had significantly higher enzyme activities and
6BH4 levels in a comparative study with dermal fibroblasts, epidermal
melanocytes, and keratinocytes under in vitro conditions. In addition, a
significantly more rapid uptake of 14C-L-phenylalanine was demonstrated in HDPC
compared with fibroblasts, whereas the differences in turnover to L-tyrosine were
insignificant, suggesting a pooling of L-phenylalanine in HDPC. These results
suggested that HDPC driven 6BH4 synthesis could be of major functional importance
in the hair cycle. In order to follow this hypothesis in vivo, expression of
enzyme activities and levels of the produced cofactor during the synchronized
hair cycle were determined employing the murine model C57BL/6. These data
revealed a significantly increased de novo synthesis for 6BH4 via GTP
cyclohydrolase I concomitant with high levels of 6BH4, and the induction of
phenylalanine hydroxylase activities during the telogen/early anagen stage (days
0-1). Pterin levels and enzyme activities fall on day 3 and plateau during the
rest of the entire cycle. In addition, thioredoxin reductase and glutathione
reductase activities were measured, where the latter enzyme remained constant but
thioredoxin reductase activities showed a biphasic behavior. The first peak
coincided with the induction of 6BH4 de novo synthesis at the beginning of the
hair cycle. The second peak was observed at mid-anagen, when melanogenesis takes
place. Taken together, our results show the presence of autocrine pterin
synthesis/recycling in human hair follicle cells under in vitro conditions, and a
possible role for 6BH4 in the synchronized murine hair cycle.
PMID- 9764832
TI - Anchorage-dependent expression of the vitamin D receptor in normal human
keratinocytes.
AB - Although the nuclear vitamin D receptor (VDR) is involved in the control of
keratinocyte proliferation and differentiation by its ligand 1,25
dihydroxyvitamin D3 [1,25(OH)2D3], its role in epidermal physiology remains
poorly understood. Because VDR abundance reflects cellular responsiveness to
1,25(OH)2D3, we investigated VDR expression in cultured human keratinocytes and
identified cell anchorage and cytoskeletal integrity as essential requirements
for the maintenance of VDR levels. Suspension culture rapidly suppressed VDR
expression and 1,25(OH)2D3 responsiveness (as estimated by induction of 24
hydroxylase mRNA), due to decreased transcription of the VDR gene. Concomitantly,
overt growth arrest with p21WAF1 induction and cyclin D1 and c-myc suppression
occurred, together with induction of differentiation markers and retinoid X
receptor alpha, the heterodimeric partner for VDR. Reattachment of suspended
keratinocytes to fibronectin led to a rapid restoration of VDR expression, which
could be blocked by RGD peptides or a blocking anti-beta1 integrin antibody. VDR
expression was also reduced by disruption of the actin cytoskeleton with
cytochalasin D. Malignant keratinocytes (SCC12B2 and A431), characterized by,
anchorage-independent growth, displayed a profound resistance to suspension
induced suppression of VDR, cyclin D1, and c-myc. Taken together, our results
associate VDR expression [and 1,25(OH)2D3 responsiveness] with cell adhesion and
an organized cytoskeleton, which are also required for cell growth of primary
cells.
PMID- 9764833
TI - The cutaneous microfibrillar apparatus contains latent transforming growth factor
beta binding protein-1 (LTBP-1) and is a repository for latent TGF-beta1.
AB - The transforming growth factors-beta1 and beta2 (TGF-beta) stimulate synthesis of
extracellular matrix proteins in vitro and appear upregulated in fibrotic
conditions, in scar formation, and in wound healing. The extracellular matrix in
turn might also act as a scavenger or repository for TGF-beta. We therefore
studied the in situ distribution of latent TGF binding protein-1 (LTBP-1) and
latent TGF-beta1 on extracellular matrix elements of normal human skin and skin
regenerating from cultured keratinocyte autografts. We localized both LTBP-1 and
latent TGF-beta1 to fibrillin-containing (elastic) microfibrils. Both LTBP-1 and
latent TGF-beta1 were already present during the earliest stages of the de novo
formation of the microfibrillar apparatus, i.e., on fusiform, randomly oriented
microfibrils that later coalesced to form the typical candelabra-like structures
in the papillary dermis. We show herewith that LTBP-1 exerts a dual role as a
component of fibrillin-microfibrils of the skin and in targeting latent TGF-beta1
to the cutaneous microfibrillar apparatus. Thus, this major connective tissue
structure does not only serve as a force bearing element and scaffold for elastin
deposition in the dermis, but also as an important repository for latent TGF-beta
in the skin.
PMID- 9764834
TI - Protein gene product 9.5 is expressed by fibroblasts in human cutaneous wounds.
AB - In a study initially designed to evaluate reinnervation of human cutaneous wounds
using an antibody to the neuroneal marker protein gene product (PGP) 9.5, we
observed marked immunostaining of cells with morphologic features of fibroblasts
in the wounds. PGP 9.5 has recently been shown to be an important enzyme in the
highly conserved ubiquitin system of proteolysis. Because the ubiquitin system is
known to play an important role in regulating the cell cycle, the presence of PGP
9.5 in cells at a wound site was of considerable interest. Our objectives were to
clarify the time frame for the appearance of PGP 9.5 and ubiquitin in wounds, to
verify that PGP 9.5 is produced by wound fibroblasts, and to evaluate a potential
role for these proteins in the tissue repair process. Standard incisional human
wounds were stained with antibodies specific for PGP 9.5 and ubiquitin. At 7 d,
stellate cells with morphologic features of fibroblasts stained for PGP 9.5,
whereas earlier wounds were generally negative. In 14 and 21 d incised wounds and
in chronic granulation tissue from nonhealing ulcers there was strong cellular
staining for PGP 9.5 and for ubiquitin. These stellate cells also showed
expression of mRNA for PGP 9.5 by reverse transcriptase-polymerase chain reaction
in situ hybridization. PGP 9.5 was detected in cultured fibroblasts both by
reverse transcriptase-polymerase chain reaction and by northern blot analysis.
Confocal microscopy showed colocalization of antibodies to PGP 9.5 and prolyl-4
hydroxylase (a fibroblast marker) as well as colocalization of PGP 9.5 and the
platelet derived growth factor beta receptor. We conclude that ubiquitin and PGP
9.5 were expressed by fibroblasts during the granulation tissue and remodeling
phases wound healing. The mRNA for PGP 9.5 was demonstrated in stellate cells in
chronic wounds and in fibroblasts in culture. The appearance of these degradative
proteins in later wounds suggests a downregulation function in the wound healing
response.
PMID- 9764835
TI - Proteolytic cleavage and activation of pro-macrophage-stimulating protein and
upregulation of its receptor in tissue injury.
AB - Macrophage stimulating protein (MSP) exists in blood as inactive pro-MSP.
Cleavage yields active MSP, the ligand for a membrane receptor (RON) that is
expressed on keratinocytes as well as macrophages. Because both cells have roles
in tissue injury, we looked for active MSP and expressed RON in wounds.
Concentration of pro-MSP + MSP in wound exudates was in the range for optimal
activity. Western blot showed that MSP comprised about half the total, in
contrast to less than 10% of the total in blood plasma. The presence of MSP was
attributed to an exudate pro-MSP convertase that had an inhibitor profile
consistent with a trypsin-like serine protease. Exudate evoked morphologic
changes in macrophages in vitro like that of MSP. Removal of this activity by an
anti-MSP column shows that exudate stimulation of macrophages is due to MSP. RON
was infrequently detected in normal skin. RON protein was markedly upregulated in
burn wound epidermis and accessory structures, in proliferating cells or
differentiated cells, or both. RON was also detected on macrophages and
capillaries. Tissue injury leads to cleavage of pro-MSP to MSP, which has
potential to act on keratinocytes, macrophages, and capillaries, all components
of the wound healing response.
PMID- 9764837
TI - Psoriatic plaques exhibit red autofluorescence that is due to protoporphyrin IX.
AB - In evaluating the autofluorescence properties of normal and diseased skin we
discovered that psoriatic plaques can emit a distinct red fluorescence when
illuminated with UVA or blue light. Using a macrospectrofluorometer equipped with
a 442 nm excitation laser, a sharp in vivo fluorescence emission peak around 635
nm could be demonstrated within the plaques of 34 of 75 (45%) patients with
psoriasis. This peak was absent from normal appearing skin of psoriatic patients
and also from the skin of 66 patients with other dermatologic diseases. A
microspectrofluorometer coupled with the same excitation laser was used to obtain
emission spectra of separated epidermal sheets and dermis from plaques
demonstrating macroscopic red autofluorescence. An emission peak around 635 nm
was observed in all three patients thus studied, but only on spectra obtained
from the epidermis. Additional spectra of vertical microscopic sections of intact
psoriatic skin from five other patients revealed that the peak originated from
the stratum corneum. Emission spectra from other microlocations including the mid
epidermis and dermis of psoriatic and normal skin, as well as the stratum corneum
of normal skin, failed to demonstrate a 635 nm peak. The excitation and emission
fluorescence spectra of acid extracts of psoriatic scale from five patients were
all similar to those of protoporphyrin IX in acid solution. High performance
liquid chromatography identified the presence of protoporphyrin IX in the acid
extracts from psoriatic scale of the same patients. We conclude that native
psoriatic plaques can exhibit red autofluorescence that is due to elevated levels
of protoporphyrin IX within scales.
PMID- 9764836
TI - Novel function of metallothionein in photoprotection: metallothionein-null mouse
exhibits reduced tolerance against ultraviolet B injury in the skin.
AB - We have shown previously that injection of cadmium chloride (Cd2+) depletes the
number of ultraviolet B (UVB)-induced sunburn cells in the mouse skin in vivo,
and that Cd2+ treatment enhances UVB resistance in cultured keratinocytes in
vitro, indicating the photoprotective role of Cd2+-induced metallothioneins (MT)
with antioxidant property against UVB injury; however, there has been no direct
evidence for the role of MT in UV protection. To improve our understanding of MT
in photoprotection, MT-null mouse deficient in its MT-1 and MT-2 genes was
studied. Skin explants were preliminarily exposed to medium alone, Cd2+ and Cd2+
plus buthionine S,R-sulfoximine, an inhibitor of glutathione synthesis. We then
compared the number of UVB-induced sunburn cells and apoptotic cells in the
epidermis of MT-null mice with that of control mice using organ culture systems.
The skin of MT-null mice developed a greater number of sunburn cells and
apoptotic cells than did that of normal mice in all experimental conditions.
These findings indicate that the skin of MT-null mouse is readily injured by UVB
irradiation. MT-null mouse provided direct evidence of the photoprotective effect
of cellular MT in the skin.
PMID- 9764838
TI - Altered expression of epithelial cell surface glycoconjugates and intermediate
filaments at the margins of mucosal wounds.
AB - Alterations in cell to cell adhesion are necessary to enable the type of cell
movements that are associated with epithelial wound healing and malignant
invasion. Several studies of transformed cells have related epithelial cell
movement to changes in the cell surface expression of the carbohydrate structures
represented by the ABO blood group antigens and, in particular, by Lewis antigens
and their biosynthetic precursors. To study further the relationship between cell
surface carbohydrates and keratinocyte cell movement, experimental wounds were
created in human oral mucosa and examined by immunohistochemical methods for
their expression of selected cytokeratins (K5, K16, K19), basement membrane
components (laminin alpha5 and gamma2-chains, BP180, collagen IV and collagen
VII), and blood group antigen precursor structures Le(x), sialosyl-Le(x), Le(y),
H antigen, N-acetyllactosamine, and sialosyl-T antigen. The changes induced by
wounding in the expression of collagen IV, laminin gamma2-chain (laminin-5), and
laminin alpha5-chain were similar to those found in skin wounds and served to
define the region of epithelial movement. This region was found to show a marked
increase in staining for both Lewis antigen Y (Le(y)) and H blood group antigen,
and decreased staining of Le(x), thus indicating an upregulation in wounded
epithelium of the fucosyltransferases responsible for the synthesis of the H
antigen. The changes in carbohydrate expression extended beyond the wound margin
into the nonwounded epithelium, a pattern of expression similar to K16, which was
also strongly upregulated in both the outgrowth and the adjacent nonwounded
epithelium. These findings provide further support for an influence of such
carbohydrate structures on the migratory behavior of epithelial cells.
PMID- 9764839
TI - Reduction of intrafollicular apoptosis in chemotherapy-induced alopecia by
topical calcitriol-analogs.
AB - Chemotherapy-induced alopecia is thought to result from cytotoxic and apoptosis
related damage to the hair follicle. This study was designed to confirm whether
keratinocyte apoptosis is indeed induced in growing (= anagen) hair follicles of
C57 BL/6 mice after the injection of cyclophosphamide, using improved methods for
histologic detection of apoptotic cells in murine skin. More importantly, we
asked whether topical calcitriol-analogs are able to modulate cyclophosphamide
induced apoptosis in vivo, because there are conflicting reports on the effects
of calcitriols on apoptosis in vitro. Anagen was induced in telogen mice on day 0
by depilation. Starting on day 5 post-depilation, the back skin of mice was
topically treated with either 0.2 microg 1,25-dihydroxyvitamin D3, 2.0 microg
calcipotriol, 0.02 microg KH 1060, or vehicle (ethanol) only. On the last day of
treatment (i.e., day 9 post-depilation), all mice received 150 mg
cyclophosphamide i.p. per kg as a single dose to induce alopecia, or vehicle
(aqua dist.). Analysis of the treated skin by in situ-end labeling (using a
modified terminal UTP nucleotide end labeling technique suitable for murine
skin), by Hoechst 33342 stain, and by DNA electrophoresis on days 10 and 14,
revealed the induction of massive apoptosis in cyclophosphamide-treated anagen
hair bulbs, which was most prominent on day 10, whereas controls showed no
follicular apoptosis. The calcitriol-pretreated groups demonstrated a significant
reduction of apoptosis, with a maximal inhibition seen on day 14. This confirms
that cyclophosphamide indeed induces massive keratinocyte apoptosis in anagen
hair follicles, and provides evidence that topical calcitriol-analogs can
suppress epithelial cell apoptosis in vivo. The mouse model employed here offers
an excellent tool for dissecting the as yet poorly understood controls of
keratinocyte apoptosis in situ and its pharmacologic manipulation.
PMID- 9764840
TI - Efficient expression of naked plasmid DNA in mucosal epithelium: prospective for
the treatment of skin lesions.
AB - Mucocutaneous gene therapy offers exciting new treatment modalities for skin
lesions. Transient expression of naked plasmid DNA could be used as a local
treatment of various skin lesions where the corresponding gene product (protein)
has therapeutic or immunization potential. We analyzed the time course,
magnitude, and histologic expression of the indicator plasmid DNA (pCMV:beta-Gal)
in mucosal epithelium and papilloma lesions. Upon direct injection of naked
plasmid DNA (20 microg) into oral mucosa, expression occurred at high local
concentrations, up to 35-fold higher than in comparable injections into the
epidermis. Due to the accelerated turnover of mucosal epithelium beta
galactosidase positive epithelial cells were detected in the basal and suprabasal
layers as early as 3 h after injection, whereas only the most superficial mucosal
layers demonstrated beta-galactosidase staining at 24 h post-injection. These
biologic characteristics need to be taken into consideration when clinical
applications of expressing naked plasmid DNA in epithelial tissues are
considered.
PMID- 9764841
TI - Differential regulation of epidermal cell tumor-antigen presentation by IL-1alpha
and IL-1beta.
AB - IL-1 exists in two forms, termed IL-1alpha and IL-1beta, which exert similar
effects in a number of biologic models. Recently, there have been reports of some
differences in the activities of these two species in some systems. To address
this issue with regard to Langerhans cells, Langerhans cell-enriched preparations
of epidermal cells were treated with either IL-1alpha or IL-1beta before pulsing
with S1509a tumor-associated antigens and subsequent use for immunization of
naive mice to S1509a. While epidermal cells treated with 100 U IL-1beta per ml
were able to induce protective tumor immunity (as indicated by the rejection of a
subsequent tumor challenge with viable S1509a tumor cells), epidermal cells
treated with 100 U IL-1alpha per ml failed to confer protective immunity. At 1000
U per ml, IL-1beta also inhibited the ability of epidermal cells to induce tumor
immunity. To investigate the effects of the two IL-1 forms on elicitation of
tumor immunity, naive mice were immunized against the S1509a tumor by s.c.
injection of dead S1509a cells. Epidermal cells enriched for Langerhans cells
were treated with either 100 U IL-1alpha or IL-1beta per ml before tumor
associated antigens-pulsing. Epidermal cells were then washed and injected into a
hind footpad of tumor immune mice and 24 h footpad swelling was assessed as a
measure of delayed-type hypersensitivity. Exposure to IL-1alpha led to suppressed
elicitation of delayed-type hypersensitivity, whereas IL-1beta treated epidermal
cells elicited a normal (100 U per ml) or enhanced (1000 U per ml) level of
delayed-type hypersensitivity. Previous experiments indicated that the
suppressive effects of IL-1alpha on induction of immunity may be mediated by TNF
alpha. Therefore, the ability of IL-1alpha or IL-1beta to induce epidermal cell
production of TNF alpha was assessed. IL-1alpha induced epidermal cells to
secrete significantly higher amounts of TNF alpha protein compared with
stimulation with IL-1beta. IL-1alpha and IL-1beta appear to differentially
regulate epidermal cell antigen presenting capability.
PMID- 9764842
TI - Endogenous EGF-family growth factors are necessary for the progression from the
G1 to S phase in human keratinocytes.
AB - Recently several endogenous epidermal growth factor (EGF)-family growth factors
(transforming growth factor-alpha, amphiregulin, and heparin-binding EGF-like
growth factor) have been identified in human keratinocytes. These factors are
known to play an important role in the regulation of cell proliferation. Here we
show that the interaction between these factors and EGF receptor are key factors
in the progression from the G1 phase to the S phase (the G1/S progression) in
human keratinocytes. In this study, human keratinocytes were cultured in serum
free MCDB153 medium and then partially synchronized by isoleucine deprivation.
After synchronization, the number of S phase cells increased and reached a
maximum after 18-24 h. The immediate addition of anti-EGF receptor blocking
antibody (1 microg per ml) to synchronized cells decreased S phase cells by 42.5%
compared with untreated keratinocytes at 18 h. By contrast, the addition of anti
EGF receptor antibodies at 12 h or later did not alter the percentage of S phase
cells. Northern blot analysis of synchronized cells demonstrated that mRNA
expression of transforming growth factor-alpha, amphiregulin, heparin-binding EGF
like growth factor, and EGF receptor reached a maximum within 0.5-3 h after
synchronization, when many cells initiated progression from the G1 to the S
phase. The results show that anti-EGF receptor antibodies block the G1/S
progression and the rapid increase of mRNA expression of endogenous EGF-family
growth factors and EGF receptor during G1/S progression. These findings indicate
that growth factor binding and EGF receptor activation are involved in the G1/S
cell cycle progression of human keratinocytes.
PMID- 9764843
TI - Patients with allergic contact dermatitis to nickel and nonallergic individuals
display different nickel-specific T cell responses. Evidence for the presence of
effector CD8+ and regulatory CD4+ T cells.
AB - To investigate the mechanisms underlying the expression of allergic contact
dermatitis, we compared the characteristics of nickel (Ni)-specific T cell
responses in 10 patients with allergic contact dermatitis to Ni and in 10
healthy, nonallergic individuals. CD4+ T cells purified from peripheral blood of
both allergic and nonallergic subjects proliferated similarly to NiSO4 in vitro,
with the responses mostly restricted to CD4+ CD45RO+ memory T cells. In contrast,
Ni-specific CD8+ T cell responses were detected only in allergic patients.
Limiting dilution assay confirmed a high frequency of Ni-specific CD4+ T cells in
both individual categories, and of Ni-specific CD8+ T cells in allergic patients,
but not in nonallergic persons. Ni-specific CD4+ T cell clones prepared from
nonallergic subjects displayed lower interferon-gamma and higher interleukin-10
production compared with T cell clones from allergic patients. The T cell skin
homing receptor, cutaneous lymphocyte-associated antigen, was expressed on the
large majority of specific CD4+ clones from both the groups. Finally, Ni-specific
CD8+ clones prepared from patients also expressed the cutaneous lymphocyte
associated antigen receptor, and released high interferon-gamma and no
interleukin-4. In aggregate, the results suggest that the presence of specific
CD8+ T cells and a distinct pattern of cytokine release (e.g., an augmented
production of interleukin-10) by CD4+ T cells can be important elements in
determining whether a hapten induces allergy or a silent immune response.
PMID- 9764844
TI - Non-coherent near infrared radiation protects normal human dermal fibroblasts
from solar ultraviolet toxicity.
AB - The sun is the most important and universal source of non-ionizing radiation shed
on human populations. Life evolved on Earth bathed by this radiation. Solar UV
damages cells, leading to deleterious conditions such as photoaging and
carcinogenesis in human skin. During the process of evolution, the cells selected
dark- and light-dependent repair mechanisms as a defence against these hazardous
effects. This study describes the induction by non-coherent infrared radiation
(700-2000 nm), in the absence of rising temperature, of a strong cellular defense
against solar UV cytotoxicity as well as induction of cell mitosis. Blocking
mitoses with arabinoside-cytosine or protein synthesis with cycloheximide did not
abolish the protection, leading to the conclusion that this protection is
independent of cell division and of protein neosynthesis. The protection provided
by infrared radiation against solar UV radiation is shown to be a long-lasting
(at least 24 h) and cumulatif phenomenon. Infrared radiation does not protect the
lipids in cellular membranes against UVA induced peroxidation. The protection is
not mediated by heat shock proteins. Living organisms on the Earth's surface are
bathed by infrared radiation every day, before being submitted to solar UV. Thus,
we propose that this as yet undescribed natural process of cell protection
against solar UV, acquired and preserved through evolutional selection, plays an
important role in life maintenance. Understanding and controlling this mechanism
could provide important keys to the prevention of solar UV damage of human skin.
PMID- 9764845
TI - Cholecalciferol induces prostaglandin E2 biosynthesis and transglutaminase
activity in human keratinocytes.
AB - In this study, we examined the effects of cholecalciferol, a primary keratinocyte
metabolite and precursor of the hydroxylated form of vitamin D3, 1alpha,25
dihydroxyvitamin D3 [1alpha,25(OH)2D3], on prostaglandin E2 (PGE2) production in
human keratinocytes by examining its respective effects on cyclooxygenase-1 (COX
1), cyclooxygenase-2 (COX-2), and cytosolic phospholipase A2 (cPLA2) expression,
the rate-limiting enzymes regulating PGE2 biosynthesis and differentiation of
keratinocytes. Cholecalciferol induced PGE2 production, whereas 1alpha,25(OH)2D3
had no effect on PGE2 production both in normal human epidermal keratinocytes and
in the immortalized human keratinocyte cell line, HaCaT. In HaCaT cells, neither
COX-1 mRNA nor protein was detectable without stimulation and COX-1 expression
did not increase in response to cholecalciferol treatment. Although cPLA2 mRNA
and protein were constitutively expressed in untreated HaCaT cells, expression
levels did not increase in response to cholecalciferol treatment; however, unlike
COX-1 and cPLA2 expression, COX-2 mRNA and COX-2 protein expression increased in
response to cholecalciferol treatment. Calphostin C, a potent protein kinase C
inhibitor, significantly reduced cholecalciferol-induced PGE2 production by
inhibiting cholecalciferol-enhanced COX-2 mRNA and protein expression. These
results indicate that (i) 1alpha,25(OH)2D3 does not induce PGE2 biosynthesis in
keratinocytes, (ii) cholecalciferol-induced PGE2 production is primarily COX-2
dependent, and (iii) cholecalciferol enhances both COX-2 mRNA and protein
expression, via a protein kinase C-dependent mechanism in human keratinocytes.
Furthermore, cholecalciferol increased total cellular transglutaminase activity
dose dependently, suggesting a potential role for cholecalciferol in regulating
the differentiation of human keratinocytes.
PMID- 9764846
TI - The herbal medicine Sho-saiko-to inhibits growth and metastasis of malignant
melanoma primarily developed in ret-transgenic mice.
AB - Sho-saiko-to is the most popular herbal medicine in Japan. We investigated the
anti-tumor and anti-metastatic effects of Sho-saiko-to and its chemically defined
ingredients on the primary skin melanoma that developed in a metallothionein-I
(MT)/ret transgenic mouse line and on a melanoma cell line (Mel-ret), which was
derived from a primary tumor developed in a MT/ret transgenic mouse. In vitro,
Sho-saiko-to suppressed the growth of Mel-ret cells more strongly than any single
ingredient of Sho-saiko-to, although baicalin as one of several ingredients
tested also suppressed it significantly. In vivo, Sho-saiko-to (i) significantly
(p < 0.02) prolonged the onset of tumor development (1.5 mo), (ii) definitely
retarded the transition to malignancy, (iii) significantly decreased the
incidence of distant metastasis to brain (p < 0.002), kidney (p < 0.05), and
liver (p < 0.05) at the malignant stage, and (iv) significantly (p < 0.02)
prolonged life span (2.6 mo). Moreover, Sho-saiko-to and baicalin down-regulated
the matrix metalloproteinase-2 and -9 expression levels, and upregulated their
inhibitor expression level in both the primary tumors and Mel-ret cells. In
conclusion, Sho-saiko-to displayed anti-tumor and anti-metastatic effects on
melanoma with regulation of the balance of matrix metalloproteinase and tissue
inhibitor of the matrix metalloproteinase levels.
PMID- 9764848
TI - Integrins of the beta1 family influence keratinocyte-lymphocyte interaction.
AB - Data from the literature indicate that ICAM-1 molecules play an important role in
keratinocyte interactions with lymphocytes via the lymphocyte function-associated
1 lymphocyte-adhesion molecule. We examined the role of beta1 integrins in
keratinocyte-lymphocyte adhesion under different activation conditions. Among the
beta1 integrins expressed on keratinocytes and lymphocytes detected by indirect
immunofluorescence microscopy and flow cytofluorometry, primarily the alpha2 and
the alpha3 subunits on both cell types were involved in keratinocyte-lymphocyte
adhesion. Moreover, the highest adhesion level was observed when both cell types
were activated by IFN-gamma for keratinocytes and phorbol 12-myristate 13-acetate
for lymphocytes, suggesting that the former involved the protein kinase C
pathway. Keratinocyte activation, characterized by the expression of ICAM-1, a
decrease of beta1 integrins, and the absence of alpha5beta1 integrin, was
required for optimal lymphocyte adhesion. Thus, beta1 integrins remaining at the
surface of IFN-gamma-treated keratinocytes could be activated by this cytokine,
and could synergize with ICAM-1 and lymphocyte function-associated-1 molecules to
consolidate keratinocyte-lymphocyte adhesion.
PMID- 9764847
TI - Interleukin-17 and interferon-gamma synergize in the enhancement of
proinflammatory cytokine production by human keratinocytes.
AB - Keratinocytes are influenced by cytokines released by skin-infiltrating T
lymphocytes. IL-17 is produced by activated CD4+ T cells and can stimulate
epithelial cells. We investigated whether IL-17 could modulate the cytokine
production and cell-surface molecule expression of keratinocytes. The effects of
IL-17 were compared with those of IFN-gamma, which is also derived from activated
T cells and is a strong stimulator for keratinocytes. IL-17 enhanced the mRNA and
protein production of the proinflammatory cytokines IL-6 and IL-8 in a
concentration-dependent way, and induced a weak expression of intercellular
adhesion molecule (ICAM)-1 and HLA-DR. The production of IL-1alpha and IL-15 was
not altered. IFN-gamma augmented the production of IL-6, IL-8, and IL-15 and
strongly induced both cell-surface molecules. IL-17 and IFN-gamma showed marked
synergism in the stimulation of IL-6 and IL-8 protein secretion and, to a lesser
extent, in the induction of ICAM-1 and HLA-DR expression. The majority of the
CD4+ and CD8+ T cell clones derived from lesional psoriatic skin expressed IL-17
mRNA, suggesting that skin-infiltrating T cells can produce this cytokine. This
IL-17 mRNA expression was detectable in T helper cell type 1 and type 2 and did
not correlate with the IFN-gamma or IL-4 production. In addition, IL-17 mRNA is
detectable in biopsies from lesional psoriatic skin, but not in nonlesional
control biopsies. Our study indicates that IL-17 is a proinflammatory cytokine,
which could amplify the development of cutaneous inflammation and may support the
maintenance of chronic dermatoses, through stimulation of keratinocytes to
augment their secretion of proinflammatory cytokines.
PMID- 9764849
TI - Curcumin induces a p53-dependent apoptosis in human basal cell carcinoma cells.
AB - Curcumin, a potent antioxidant and chemopreventive agent, has recently been found
to be capable of inducing apoptosis in human hepatoma and leukemia cells by way
of an elusive mechanism. Here, we demonstrate that curcumin also induces
apoptosis in human basal cell carcinoma cells in a dose- and time-dependent
manner, as evidenced by internucleosomal DNA fragmentation and morphologic
change. In our study, consistent with the occurrence of DNA fragmentation,
nuclear p53 protein initially increased at 12 h and peaked at 48 h after curcumin
treatment. Prior treatment of cells with cycloheximide or actinomycin D abolished
the p53 increase and apoptosis induced by curcumin, suggesting that either de
novo p53 protein synthesis or some proteins synthesis for stabilization of p53 is
required for apoptosis. In electrophoretic mobility gel-shift assays, nuclear
extracts of cells treated with curcumin displayed distinct patterns of binding
between p53 and its consensus binding site. Supportive of these findings, p53
downstream targets, including p21(CIP1/WAF1) and Gadd45, could be induced to
localize on the nucleus by curcumin with similar p53 kinetics. Moreover, we
immunoprecipitated extracts from basal cell carcinoma cells with different anti
p53 antibodies, which are known to be specific for wild-type or mutant p53
protein. The results reveal that basal cell carcinoma cells contain exclusively
wild-type p53; however, curcumin treatment did not interfere with cell cycling.
Similarly, the apoptosis suppressor Bcl-2 and promoter Bax were not changed with
the curcumin treatment. Finally, treatment of cells with p53 antisense
oligonucleotide could effectively prevent curcumin-induced intracellular p53
protein increase and apoptosis, but sense p53 oligonucleotide could not. Thus,
our data suggest that the p53-associated signaling pathway is critically involved
in curcumin-mediated apoptotic cell death. This evidence also suggests that
curcumin may be a potent agent for skin cancer prevention or therapy.
PMID- 9764850
TI - Antibody responses to melanoma/melanocyte autoantigens in melanoma patients.
AB - Melanogenesis-related proteins play important roles in melanin synthesis and
antigenicity of melanomas. Identification of highly expressed melanoma-associated
antigens (MAA) that are immunogenic in humans will provide potential targets for
cancer vaccines. Melanogenesis-related proteins have been shown to be MAA.
Autoantibody responses to these MAA have been shown to react with melanoma cells
and melanocytes, and suggested to play a role in controlling melanoma
progression. To assess antibody responses to potential melanoma/melanocyte
autoantigens, the open-reading frame sequences of tyrosinase, tyrosinase-related
protein (TRP)-1, TRP-2, and melanoma-associated glycoprotein antigen family
(gp100/pmel17) genes were cloned and expressed as recombinant proteins in E.
coli. Purified recombinant antigens were employed to detect antibodies in sera of
melanoma patients and normal healthy donors. By affinity enzyme-linked
immunosorbent assay and western blotting, all recombinant antigens were shown to
be antigenic. The main subclass of antibody response to these antigens was IgG.
Most importantly this study demonstrated anti-TRP-2 and anti-gp100/pmel17 IgG
responses in melanoma patients. Only one of 23 normal donors had an antibody
response to the antigens tested. MAA-specific IgG antibodies in sera were
assessed in melanoma patients (n = 23) pre- and post-polyvalent melanoma cell
vaccine treatment. Polyvalent melanoma cell vaccine treatment enhanced anti-MAA
antibody responses; however, only anti-TRP-2 and anti-gp100/pmel17 antibody
response was enhanced. These studies suggest that four melanogenesis-related
proteins are autoimmunogenic and can be used as potential targets for active
specific immunotherapy.
PMID- 9764851
TI - Human Langerhans cells express a novel form of the leukocyte common antigen
(CD45).
AB - CD45 is a family of transmembrane glycoproteins that function as protein tyrosine
phosphatases. All isoforms exhibit common CD45 epitopes, whereas the restricted
CD45 epitopes (RA, RB, and RO) are each limited to one or more isoforms. In prior
studies, we showed that human Langerhans cells in normal epidermis express a
novel CD45 phenotype. They express common CD45 epitopes but are
characteristically RA- RB- RO-. This suggests that Langerhans cells can express a
novel form of CD45. In order to clarify this issue further, mRNA extracted from
enriched Langerhans cell preparations was reverse transcribed into cDNA. The 5'
portion of CD45 cDNA was then amplified using polymerase chain reaction primers
complementary to exon 2 and exons 9-10, which flank the CD45 variable exon region
(exons 4-6). Cloning and sequencing of the dominant 441 bp polymerase chain
reaction product revealed the following exon configuration for the 5' translated
region of Langerhans cells CD45: exon 3/7/8/9/10. This is the same exon
configuration associated with the 180 kd CD45 isoform expressed by memory T cells
and monocytes/macrophages; however, these cell types are RO+ whereas normal
Langerhans cells are RO-. The RO epitope is known to be an oligosaccharide with a
terminal sialic acid moiety. Therefore, we determined the expression of a related
epitope, OPD4, by Langerhans cells. This is another terminal sialic acid moiety
expressed by the 180 kd CD45 isoform of memory T cells but not by
monocytes/macrophages. Langerhans cells were OPD4-. Our data suggest that memory
T cells, monocytes/macrophages, and Langerhans cells all express a common CD45
transcript lacking exons 4-6; however, this transcript appears to undergo lineage
specific, post-translational glycosylation to create three distinct CD45
glycoproteins: RO+ OPD4+, RO+ OPD4-, and RO- OPD4-, which are expressed typically
by memory T cells, monocytes/macrophages, and Langerhans cells, respectively.
Because these epitopes are located extracellularly, they are postulated to allow
differential responses to extracellular stimuli by creating differential ligand
specificity.
PMID- 9764852
TI - The pH gradient over the stratum corneum differs in X-linked recessive and
autosomal dominant ichthyosis: a clue to the molecular origin of the "acid skin
mantle"?
AB - In a search for pathogenetic mechanisms underlying retention hyperkeratosis, we
examined the pH gradient over the stratum corneum in 13 male patients suffering
from either x-linked recessive (XRI) or autosomal dominant ichthyosis vulgaris.
For recording pH values, a flat glass electrode was repeatedly applied to the
skin during tape stripping of mildly involved forearm skin. Before stripping,
surface pH was higher in ichthyosis vulgaris (5.3 +/- 0.7; n = 7) than in XRI
(4.6 +/- 0.4; n = 6; p < 0.05) and healthy control men (4.5 +/- 0.2; n = 7; p <
0.01). Removal of stratum corneum, which required 100-240 strippings in
ichthyotic skin and 80-120 strippings in healthy control skin, disclosed markedly
different pH variations in the two types of ichthyosis. The major abnormality in
ichthyosis vulgaris skin was that a neutral pH was attained already halfway
through the horny layer, possibly reflecting a congenital lack of acidic
breakdown products from keratohyaline. By contrast, stripping of XRI skin
revealed a shallow pH gradient that plateaued at 6.2-6.6, instead of about 7 as
in normal and ichthyosis vulgaris skin. A likely explanation is the XRI
associated accumulation of cholesterol sulfate in lower stratum corneum. Our
results suggest that the "acid mantle" of normal skin, which penetrates deep into
the stratum corneum, is the combined result of cornification-associated organic
acids and back-diffusion of acid material from the surface. Because corneocyte
desquamation involves many pH-dependent enzymes, abnormalities in the
transcorneal pH gradient might play a role in the pathogenesis of ichthyosis.
PMID- 9764853
TI - (Pheo)melanin photosensitizes UVA-induced DNA damage in cultured human
melanocytes.
AB - The question of whether melanins are photoprotecting and/or photosensitizing in
human skin cells continues to be debated. To evaluate the role of melanin upon
UVA irradiation, DNA single-strand breaks (ssb) were measured in human
melanocytes differing only in the amount of pigment produced by culturing at two
different concentrations, basic (0.01 mM) or high (0.2 mM), of L-tyrosine, the
main precursor of melanin. In parallel, pheo- and total melanin contents of the
cells were determined. Identical experiments were performed with two melanocyte
cultures derived from a skin type I and a skin type VI individual. For the first
time the correlation between UVA-induced genotoxicity and pheo-/total melanin
content has been investigated. We observed that cultured in basic medium, the
skin type VI melanocytes contained 10 times more total melanin and about seven
times more pheomelanin than the skin type I melanocytes. Elevation of tyrosine
level in the culture medium resulted in an increase of both pheo- and total
melanin levels in both melanocyte cultures; however, the melanin composition of
skin type I melanocytes became more pheomelanogenic, whereas that of skin type VI
melanocytes remained the same. The skin type VI melanocytes cultured in basic
medium demonstrated a very high sensitivity (1.18 ssb per 10(10) Da per kJ per
m2) toward UVA that is probably related to their high pheo- and total melanin
content. Their UVA sensitivity, however, did not change after increasing their
melanin content by culturing at high tyrosine concentration. In contrast, the
skin type I melanocytes demonstrated a low sensitivity (0.04 ssb per 10(10) Da
per kJ per m2) toward UVA when cultured in basic medium, but increasing their
melanin content resulted in a 3-fold increase in their UVA sensitivity (0.13 ssb
per 10(10) Da per kJ per m2). These results demonstrate that UVA-irradiated
cultured human melanocytes are photosensitized by their own synthesized
chromophores, most likely pheomelanin and/or melanin intermediates.
PMID- 9764854
TI - Effects of UVB on the synthesis of complement proteins by keratinocytes.
AB - UVB exposure of the skin results in increased production of several cytokines by
keratinocytes and infiltration of inflammatory cells. We hypothesized that UVB
may increase the expression of complement (C) components and C-regulatory
proteins by keratinocytes. In vivo, UVB may upregulate these proteins by direct
effects or via cytokines released by keratinocytes or infiltrating inflammatory
cells. In vitro, UVB may upregulate these proteins only directly, because of
dilution of released cytokines in the medium. To test this, we exposed cultured
human keratinocytes to UVB (0-64 J per m2) and monitored C3 and Factor B release
in the medium by enzyme-linked immunosorbent assay, and surface expression of
decay accelerating factor, membrane cofactor protein, and CD59 by flow cytometry.
Keratinocytes produced small amounts of C3 and Factor B, which remained
unaffected by UVB. UVB (32 J per m2) caused a transient upregulation of all three
C-regulatory proteins. Decay accelerating factor expression was maximal at 48 h
(1.81 +/- 0.06-fold increase in mean fluorescence intensity over nonexposed
cells), membrane cofactor protein at 72 h (2.13 +/- 0.09-fold increase in mean
fluorescence intensity), and CD59 at 120 h (1.96 +/- 0.09-fold increase in mean
fluorescence intensity), returning to baseline values within 96, 192, and 192 h,
respectively. Exposure to 64 J per m2 resulted in significant cell death; cells
surviving this dose up to 48 h expressed a higher level of all the three proteins
than those surviving 32 J per m2. In conclusion, UVB upregulated membrane
cofactor protein, decay accelerating factor, and CD59 on keratinocytes without
affecting the constitutive release of C3 and Factor B. Thus, UVB can increase the
resistance of keratinocytes against their own C known to be produced excessively
in response to cytokines of inflammatory cells that infiltrate the skin following
UVB exposure.
PMID- 9764855
TI - Phenotypic characterization of human skin mast cells by combined staining with
toluidine blue and CD antibodies.
AB - Mast cells (MC) are important cellular components of the immune network in
diverse organs. The skin MC has likewise been implicated in IgE- and complement
mediated cutaneous reactions. Such reactions supposedly involve specific cell
surface membrane receptors. In this study, the cell surface marker profile of
human skin MC was established using monoclonal antibodies (MoAb) against defined
CD antigens. MC were isolated from juvenile foreskin (n = 55) and adult mammary
skin (n = 5). The reactivity of MC with MoAb was assessed by a combined toluidine
blue/immunofluorescence staining technique. Confirming our previous analyses on
lung MC, foreskin MC reacted with MoAb against CD9, CD29, CD33, CD43, CD44, CD45,
CD46, CD51, CD54, CD55, CD58, CD59, CD61, and CD117 (c-kit). Foreskin MC were
also recognized by MoAb to CD47, CD48, CD49d, CD53, CD60, CD63, CD81, CD82, CD84,
CD87, CD92, CD97, CD98, and CD99. Recently clustered CD antigens detectable on
foreskin MC were CD147 (neurothelin), CD149 (MEM133), CD151 (PETA-3), and CD157
(BST-1). In contrast to lung MC and MC from adult skin, foreskin MC were found to
express CD88 (C5aR). Also, cutaneous MC (from both juvenile foreskin and adult
mammary skin), but not lung MC, were found to bind the CD32 MoAb IV.3, 2E1, and
FLI8.26 (Fc gammaRII). The CD50 antigen (ICAM-3) was detectable on lung MC, but
not on foreskin MC or MC of adult mammary skin. In summary, our data show that
cutaneous MC and lung MC express an almost identical phenotype; however, in
contrast to lung MC, cutaneous MC appear to express substantial amounts of CD32
and to lack CD50. In addition, foreskin MC, unlike MC from adult skin or lung,
express CD88.
PMID- 9764856
TI - Prevalence of antibodies against virus-like particles of Epidermodysplasia
verruciformis-associated HPV8 in patients at risk of skin cancer.
AB - There is increasing evidence for widespread occurrences of infection with
Epidermodysplasia verruciformis-related human papillomaviruses, both in the
general population and in immunosuppressed patients. In order to test for the
prevalence of antibodies directed against the native L1 epitopes exposed on the
surface of the virions, we have established an IgG-specific enzyme-linked
immunosorbent assay with L1 virus-like particles of the Epidermodysplasia
verruciformis-specific human papillomavirus 8 as antigen to screen 567
representative serum samples from the general population and
immunosuppressed/dermatologic patients. Among healthy European donors (n = 210),
7.6% were found to be seropositive. In a group of renal transplant recipients (n
= 185) the antibody prevalence was elevated to 21.1%, irrespective of the
presence or absence of skin cancer. High positivity rates could be detected among
(i) immunocompetent patients with nonmelanoma skin tumors (45.6%, n = 79) and
(ii) Psoralene/UVA treated psoriasis patients (42.9%, n = 42). In contrast, anti
human papillomavirus 8-virus-like particle antibodies were found in only 6.8% of
Hodgkin lymphoma patients (n = 44).
PMID- 9764857
TI - A novel insertional mutation in loricrin in Vohwinkel's Keratoderma.
AB - A mutation in the gene encoding loricrin has recently been reported in a subset
of patients with Vohwinkel's Keratoderma manifesting an associated ichthyosiform
dermatosis. We have studied a further kindred with this clinical phenotype.
Microsatellite marker analysis was consistent with linkage to chromosome 1q21 and
direct sequencing of loricrin identified a heterozygous mutation with an
insertion of a T residue at codon 209. This mutation is predicted to produce a
mutant protein with a frameshift of its terminal 107 amino acids and to be 22
amino acids longer than the wild-type protein due to a delayed termination codon.
The only previously reported mutation is a G insertion producing a frameshift
after codon 231. The novel mutation we report is likely to have a similar
functional effect on cornified envelope formation, with disturbance of
transglutaminase-mediated cross-linking of envelope components, and serves to
confirm the predicted role of insertional mutations in Vohwinkel's Keratoderma
associated with ichthyosis.
PMID- 9764858
TI - Urocanic acid binds to GABA but not to histamine (H1, H2, or H3) receptors.
PMID- 9764859
TI - UV immunosuppression and skin cancer.
PMID- 9764860
TI - Problems related to circadian rhythms in human skin and their validation.
PMID- 9764861
TI - Mitochondrial DNA deletions in human skin reflect photo- rather than chronologic
aging.
PMID- 9764862
TI - Gynecologic effects of tamoxifen and the association with endometrial carcinoma.
AB - Tamoxifen has been used as an adjuvant therapy for breast cancer for nearly two
decades. The benefits of adjuvant tamoxifen therapy in prolonging disease-free
and overall survival have been shown in randomized clinical trials. Despite this,
some developing evidence suggests that tamoxifen causes a 2- to 3-fold increase
in endometrial cancer. This paper reviews the reports of endometrial carcinoma in
tamoxifen-treated patients. Two hundred fifty cases of endometrial carcinoma are
reported, but only one case is identified in a premenopausal woman. When
documented, 77% (n=127) of the cases are good-grade (grade 1 or 2) and 80%
(n=125) are stage-I disease. Since the distribution of good grade (79%) and stage
I (74%) from the Surveillance, Epidemiology and End Results (SEER) data are
comparable, concerns about more aggressive or late-stage disease appear to be
unwarranted. The modest increase in the incidence of early-stage, good-grade
endometrial carcinoma described during tamoxifen therapy suggests that it would
be unreasonable to institute an aggressive detection strategy of endometrial
biopsies. This approach would only lead to further detection bias and would not
be cost-effective. Physicians should ensure that patients do not have pre
existing endometrial cancer prior to adjuvant tamoxifen therapy for breast cancer
and, furthermore, they should educate patients about signs and symptoms of early
endometrial carcinoma and when reported these should be followed up with a
gynecologic examination.
PMID- 9764863
TI - Serum CA 125 and first trimester abortion.
AB - OBJECTIVE: The study was carried out to assess the clinical value of serum CA 125
in association with serum beta-human chorionic gonadotropin (hCG) for predicting
pregnancy outcome. METHODS: One hundred spontaneous pregnancies, 52 non
threatened pregnancies and 48 with threatened abortions, observed in the
Department of Obstetrics and Gynecology at the University 'La Sapienza', Rome,
Italy, were evaluated during the first trimester using ultrasound examination, CA
125 and beta-hCG titrations. RESULTS: Threatened pregnancies had statistically
significantly higher CA 125 serum values than non-threatened pregnancies,
especially those with a negative outcome (P < 0.01). The CA 125 levels in the
threatened pregnancies were positively correlated with the tropho-decidual
hematoma volume (r=0.839, P < 0.0001). The CA 125-beta-hCG association showed a
higher prognostic value (sensitivity 78.9%, specificity 96.5%) in assessing
pregnancy outcome than CA 125 or 0-hCG alone (sensitivity 78.9% and 57.9%,
respectively; specificity 75.8% and 86.2%, respectively). CONCLUSIONS: Our
findings are in accordance with the hypothesis of a tropho-decidual origin of
this marker, suggesting its possible usefulness in the prognostic evaluation of
first trimester threatened abortion.
PMID- 9764864
TI - Oral nifedipine therapy in the management of severe preeclampsia.
AB - OBJECTIVE: The purpose of this study was to compare the efficacy of nifedipine
(Cordipin) and hydralazine in lowering blood pressure in severe preeclampsia.
METHOD: A randomized, prospective study of 104 patients with severe preeclampsia
in the Department of Obstetrics and Gynecology, Korle-Bu Teaching Hospital,
Accra, Ghana, was conducted between January 1992 and June 1994. RESULTS: Of the
104 patients recruited into the study, six did not deliver at our hospital and
were thus excluded from the study. Nifedipine and hydralazine as first-line drugs
controlled the blood pressure in 44 and 35 patients, respectively, but failed in
5 and 14, respectively. This was statistically significant (P < 0.05). The mean
birth weight was higher in the nifedipine group (2500+/-800 g vs. 2400+/-800 g).
There were 11 admissions to the neonatal intensive care unit in the nifedipine
group and 13 in the hydralazine group but the difference was not statistically
significant. CONCLUSION: Nifedipine and hydralazine could both be used
effectively to control blood pressure in severe preeclampsia in our subregion.
While hydralazine is administered intravenously and needs strict monitoring,
nifedipine is more effective, is easy to administer orally, less demanding on
hospital staff, convenient and more predictable.
PMID- 9764865
TI - Urogenital infection in preeclampsia.
AB - OBJECTIVE: The purpose of this study was to determine whether the incidence of
urinary tract infections and postpartum endometritis were increased in
preeclamptic pregnancies. METHOD: We conducted a retrospective study of 13852
pregnant women, using a perinatal database at The Johns Hopkins Hospital, over
the past 5 years. The incidence of urinary tract infections and postpartum
endometritis was analyzed using the chi-squared test and logistic regression
analysis. Statistical significance was set at P < 0.05. RESULTS: There were 345
(2.5%) mild preeclamptics and 440 (3.2%) severe preeclamptics. The incidence of
urinary tract infections and postpartum endometritis in preeclamptic patients was
significantly higher than that in non-hypertensive pregnant patients. After
controlling for confounding variables, severe preeclampsia was still found to be
an independent significant risk factor for both urinary tract infections and
postpartum endometritis. CONCLUSION: Our data show a significant increase in
urogenital infection in preeclamptic pregnancy. This may reflect higher rates of
underlying renal disease and placental bed abnormalities occurring in
preeclampsia.
PMID- 9764866
TI - Electromyographic activity in cervices with very low Bishop score during labor.
AB - OBJECTIVES: To investigate the activity of the smooth muscles in the cervix at
the onset of induced labor and to further elucidate this activity in relation to
uterine contractions and to the duration of the latent phase of labor, taking
cervical ripeness into account. METHODS: Cervical electromyographic (EMG)
activity was studied at the onset of labor induced with amniotomy and oxytocin.
Bipolar measurement of cervical electrical activity was performed. The root mean
square of the cervical EMG activity and the intensity of intrauterine pressure in
two groups of parturients with different cervical ripeness were compared.
RESULTS: The EMG activity was higher in the group with lower Bishop scores. We
found a significant positive correlation between EMG activity and duration of the
latent phase of labor. CONCLUSION: Smooth muscles in the human cervix are active
during labor and act to some extent independently of the uterine corpus.
PMID- 9764867
TI - Free alpha-subunits of human chorionic gonadotropin in preeclampsia.
AB - OBJECTIVE: To investigate free alpha-human chorionic gonadotropin (hCG) as a
marker of preeclampsia. METHODS: Four groups of patients were studied: normal
pregnancies, preeclampsia, eclampsia and normal pregnant women <20 weeks'
gestation. Patients were further divided according to parity and gestational age
(< or =20, 21-30, 31-40 weeks). An immunoradiometric assay employing monoclonal
antibodies specific for free alpha-hCG was used. RESULTS: A total of 313 patients
were analyzed. Thirty-four patients < or =20 weeks' gestation were followed until
delivery: five (14.7%) developed preeclampsia; none had abnormal alpha-hCG levels
before onset of preeclampsia. Patients with preeclampsia (21-30 weeks' gestation)
demonstrated a mean alpha-hCG level greater than that of normotensive controls
but this was not statistically significant. Between 31 and 40 weeks' gestation,
mean alpha-hCG levels in the hypertensive and control groups were 210.8 ng/ml and
115.8 ng/ml, respectively (P < 0.001). A stronger association was observed
between alpha-hCG and preeclampsia with increasing gestational age (relative risk
[RR] 2.07, 21-30 weeks; RR 3.02, 31-40 weeks) and severity (RR 4.51, mild; RR
12.15, severe; RR 16.88, eclampsia). CONCLUSION: There is a strong association
between alpha-hCG and preeclampsia, nevertheless this test is unsuitable for
predicting preeclampsia.
PMID- 9764868
TI - Magnesium sulfate as an anticonvulsant in eclampsia.
AB - OBJECTIVE: To examine the efficacy of magnesium sulfate (MgSO4) as an
anticonvulsant in eclampsia and imminent eclampsia. METHODS: Case records of 562
consecutive patients with eclampsia and 174 with imminent eclampsia treated at
the Institute of Obstetrics and Gynaecology, Hyderabad, India, during the 3-year
period from January 1987 to December 1989, were reviewed. Management consisted
of: (1) MgSO4 to control convulsions; (2) sublingual nifedipine to control
hypertension; and (3) delivery of the fetus. RESULTS: Convulsions were controlled
in 95% of cases with the initial dose of magnesium and within half an hour in a
further 2%. Cesarean section was performed mainly for obstetric indications.
Depression of knee jerks was found to be the first sign of impending magnesium
toxicity and with the precautions observed, magnesium toxicity was negligible.
Maternal mortality was 2.4% (18 maternal deaths) and perinatal mortality 36% (247
perinatal deaths). Sixteen women with eclampsia (2.8%) and two with imminent
eclampsia (1.1%) died. Of the 247 perinatal deaths, 61 were in the category of
imminent eclampsia. There were 10 sets of twins. Cerebrovascular accident was the
leading cause of maternal death. Fetal deaths and prematurity were important
causes of perinatal loss. CONCLUSIONS: The control of convulsions is the most
important aspect in the management of eclampsia, and MgSO4 is a very effective
anticonvulsant.
PMID- 9764870
TI - Interleukin-1 receptor antagonist expression in epithelial cells of human
endometrium.
AB - OBJECTIVE: To examine the expression of interleukin-1 (IL-1) and IL-1 receptor
antagonist (IL-1ra) in the human endometrium in the follicular and luteal phases.
METHODS: The concentrations of IL-1alpha and IL-1beta in the culture supernatants
of endometrial cells were determined by enzyme-linked immunosorbent assay.
Transcription of the IL-1ra gene in the endometrium was investigated by reverse
polymerase chain reaction (PCR). Human endometrium was immunohistochemically
stained using a monoclonal antibody specific to IL-1ra. RESULTS: The
concentrations of IL-1alpha and IL-1beta in the culture supernatants were 11 and
55 pg/ml, respectively, in the follicular phase, and 10 and 40 pg/ml,
respectively, in the luteal phase. The concentration of IL-1ra was 465 pg/ml in
the follicular phase and 1710 pg/ml in the luteal phase. Densitometric analysis
of the reverse PCR products showed that the expression of IL-1ra mRNA was
increased in endometrial cells in the luteal phase. Immunohistochemical staining
revealed that epithelial cells were the main source of IL-1ra in human
endometrium. CONCLUSIONS: Human endometrial cells produce IL-1 (mainly IL-1beta)
and IL-1ra. The level of IL-1ra production in human endometrial epithelial cells
was greater in the luteal phase than in the follicular phase due to the increased
transcription of the IL-1ra gene.
PMID- 9764869
TI - The effect of regular exercise on women receiving danazol for treatment of
endometriosis.
AB - OBJECTIVE: To determine the effects of regular exercise on women receiving
danazol for the treatment of endometriosis. METHODS: Thirty-nine patients were
randomized to a danazol-only or a danazol/exercise regimen in a prospective
clinical trial carried out at tertiary care institutions. Patients in the
danazol/exercise group were instructed to exercise four times per week, for 40
min per session, at an intensity of 20 metabolic units. Side effect profiles,
pelvic symptoms, aerobic fitness, strength and hormone levels were compared for
all subjects. The number of side effects of danazol was analyzed by the method of
generalized estimating equations. RESULTS: The number of side effects reported
during a 4-week period was 1.09-2.17 times greater for the danazol-only than for
the danazol/exercise group. All patients had improvement of symptoms during
treatment. The danazol/exercise group had significantly lower testosterone levels
during treatment. The time to recurrence of endometriosis was not different
between groups. CONCLUSIONS: Exercise during danazol therapy reduces the number
of androgenic side effects. Relief of pain and time to recurrence are unaffected.
PMID- 9764871
TI - Laparoscopic para-aortic lymph node sampling in the staging of invasive cervical
carcinoma: including a comparative study of 21 laparotomy cases.
AB - OBJECTIVES: To assess the efficacy and risks of laparoscopic para-aortic lymph
node sampling compared with standard laparotomy in staging cervical carcinoma.
METHODS: From August 1993 through July 1994, 38 patients with biopsy-proven
invasive cervical carcinoma (24 early and 14 advanced invasive cancers) were
entered into the study. This was a prospective study of laparoscopic para-aortic
lymphadenectomy in invasive cervical carcinoma, with patients serving as their
own controls. Video laparoscopic lymph node sampling was performed. In patients
with early invasive cancer, the nodes were sent for frozen section and, if
negative, laparotomy was performed to look for any residual nodes. Radical
hysterectomy was performed immediately if residual nodes were negative. Patients
with either nodal metastasis on frozen section or with advanced cancer underwent
para-aortic lymphadenectomy only. The operative technique was also evaluated.
RESULTS: Laparoscopy required an average of 77 min (S.D. 40), with an average
blood loss of 116 ml (S.D. 321). The average number of nodes was 15 (S.D. 7). At
subsequent laparotomy the average number of residual nodes found was 0.4 (S.D.
0.9) and none showed metastasis. One vena cava laceration and one ureteral injury
required immediate repair, and two patients were too obese to undergo
laparoscopy. CONCLUSIONS: Laparoscopic para-aortic lymph node sampling is a less
invasive, reliable method for staging invasive cervical carcinoma and can
substitute for traditional open procedures. The incidence of risks with this
method appears to be low.
PMID- 9764872
TI - Pregnancy and its outcome in quadriplegia due to Pott's spine.
AB - Pregnancy with quadriplegia is a problem sometimes encountered in obstetric
practice. The etiology of quadriplegia in the developed world is mainly spinal
cord tumor or accident, while in the developing countries the main cause is
tuberculosis of the spine. We report the management of two pregnant patients with
quadriplegia due to tuberculosis of the cervical spine. Worsening of the
neurological condition necessitated early surgical intervention, and termination
of pregnancy was advised in both patients. Literature on the subject makes
frequent reference to the life-threatening complication of autonomic
hyperreflexia encountered during pregnancy and delivery. It is characterized by
sweating, headache, severe hypertension leading to unconsciousness and
convulsions. These complications, surprisingly, were absent in both of our
patients.
PMID- 9764873
TI - Echinococcosis of the liver during pregnancy.
AB - A 20-year-old Turkish woman with three huge echinococcus cysts of the liver was
admitted in the third trimester of pregnancy. During pregnancy she received
albendazole and during vaginal delivery she received both albendazole and
medication aimed at preventing anaphylactic reaction. We believe that the
presence of large hydatid cysts during pregnancy should be managed conservatively
with courses of albendazole after the first trimester of pregnancy.
PMID- 9764875
TI - Oral pyogenic granuloma in pregnancy.
PMID- 9764874
TI - Ultrasonographic appearance of fallopian tube carcinoma.
AB - Preoperative diagnosis of tubal carcinoma is difficult and a diagnosis cannot
usually be established until the time of operation. However, since prognosis is
strictly related to the stage of the neoplasm, it is very important to be
familiar with the clinical and imaging characteristics of primary fallopian tube
carcinoma in order to make an early and accurate diagnosis. This report presents
the ultrasonographic features of three cases of fallopian tube carcinoma and
reviews the literature on the subject.
PMID- 9764876
TI - Epiphenomenal antiovarian antibodies in hypogonadotropic hypogonadism.
PMID- 9764877
TI - Significance of intrauterine gas at postpartum ultrasonography.
PMID- 9764878
TI - Self-inflicted vaginal bleeding.
PMID- 9764879
TI - Tuboperitoneal fistula after salpingostomy.
PMID- 9764880
TI - ACOG technical bulletin. Evaluation and treatment of hirsute women. Number 203 --
March 1995 (replaces no. 103, April 1987). American College of Obstetricians and
Gynecologists.
PMID- 9764881
TI - ACOG committee opinion. Condom availability for adolescents. Number 154 -- April
1995. Committee on Adolescent Health Care. American College of Obstetricians and
Gynecologists.
PMID- 9764882
TI - Influence of breastfeeding and complementary food on growth between 5 and 10
months.
AB - The aim of this study was to examine the nature of the association between
breastfeeding, complementary feeding and growth in a random sample of infants
from Denmark, where the prevalence of breastfeeding is high. A semiquantitative
food frequency questionnaire and a questionnaire on breastfeeding duration and on
weight and length measurements taken at the infant welfare visit at 5 and 10
months were sent to 590 families with 10-month-old infants. A total of 339
infants with complete growth data were included in the analyses. When controlling
for mid-parental height and birth weight infants breastfed for > or =7 months
gained 198 g less in weight (p < 0.01) and 7 mm less in length (p < 0.01) during
the period from 5 to 10 months than infants breastfed for < 7 months. Controlling
for these effects, the 10% of the sample with the highest protein intake (i.e. >
or =16 energy percentage) gained 262 g more than those with a lower protein
intake (p = 0.03). Infants breastfed for > or =7 months received significantly
less cow's milk (p < 0.01), and fewer meat-containing dishes (p < 0.05) and
sweets or cakes (p < 0.01), which may partly explain the effect of breastfeeding.
The long-term consequences of this moderate difference in growth velocity are
unknown and the findings should not be used to advocate against breastfeeding
during late infancy.
PMID- 9764883
TI - High-density lipoprotein subclasses and esterification rate of cholesterol in
children: effect of gender and age.
AB - Since the development of coronary heart disease (CAD) is affected by a specific
pattern of plasma high density lipoprotein (HDL) effects it may be useful to know
whether this occurs already in childhood. In this study we evaluated particle
size distribution of HDL by gradient gel electrophoresis and the determination of
cholesterol esterification rate (FER(HDL)) in plasma depleted of apo B
lipoproteins in 221 children (108 boys and 113 girls) aged 4 months to 20 years.
Total plasma- (TC), low-density lipoprotein- (LDL-C) and HDL- (HDL-C)
cholesterol, HDL unesterified cholesterol (HDL-UC) and plasma triglycerides (TG)
were also measured. There were no significant gender and age differences with
respect to the plasma TC, LDL-TC and TG but concentration of HDL-TC increased
with age. Post-pubertal girls had significantly higher relative concentrations of
HDL2b compared to boys (30.4% vs 17.2%), while HDL3b,c was lower in post-pubertal
girls (8.7% vs. 16.5%). FER(HDL) correlated inversely with HDL2b and positively
with HDL3b,c particles and was significantly higher in boys of the post-pubertal
group compared to girls (16.9%/h vs 12.5%/h). While in girls there was a positive
correlation between age and HDL-C, HDL-UC and the relative concentration of HDL2b
no significant correlation were observed in boys. In girls the increase in TC
showed a significant correlation with a simultaneous increase in HDL-C, HDL-UC
and HDL2b. In boys TC correlated significantly with changes in TG only. When
HDL2b and HDL3b,c cholesterol levels are calculated from HDL-C concentration and
per cent distribution the differences between males and females are further
emphasized. These data indicate that HDL particle size distribution is age- and
gender-dependent.
PMID- 9764884
TI - Dual energy X-ray absorptiometry of the hand and wrist--a possible technique to
assess skeletal maturation: methodology and data in normal youths.
AB - Ninety five normal Caucasian subjects (51F, 44M) aged from 2 to 25 y were
measured at the hand and wrist level with a small DXA system (pDEXA) in order to
obtain the normal values of the bone mineral content (BMC), density (BMD) and
projected area (A) of carpal (c) and metacarpal (m) bones. BMDc ranged from 0.065
+/- 0.007 g/cm2 to 0.365 +/- 0.035 g/cm2 in females and 0.425 +/- 0.040 g/cm2 in
males. It presented a sharp change of increase rate at 15.5 and 17 y of age in
girls and boys, respectively. Ac presented the same kind of evolution as BMDc,
but had a larger value dispersion. The second metacarpal bone had the highest
BMCm value in 85% of females and 90% of males. The sum of BMCmi or Ami values (i
= 1-5) and the projected mean density of the 5 metacarpal bones was well
correlated with BMCc, Ac and BMDc, respectively (r > 0.90). A volumetric mineral
density, dmi, calculated for each of these bones, approximated to a cylinder, was
correlated with age (r > 0.85).
PMID- 9764885
TI - Diurnal rhythm of serum osteocalcin in normal children.
AB - The aim of the present study was to assess diurnal levels of serum osteocalcin in
normal children using a recently introduced fluoroimmunoassay (Pharmacia
Osteocalcin CAP FEIA) measuring solely the intact peptide. Five girls and two
boys aged 10.4-13.6 (mean 12.2) y were studied. Blood samples for determination
of osteocalcin were collected every 2h throughout the day. A statistically
significant rise in serum osteocalcin (F = 6.7, p < 0.001) with a peak at 08.00 h
and a nadir lasting from 10.00 to 24.00 h was found. Trough and peak levels (at
16.00 and 08.00 h, respectively) were 41.6 +/- 6.8 and 66.0 +/- 10.5 microg l(-1)
(mean +/- SEM). The circadian variation should be taken into consideration when
single assessments of serum osteocalcin in children are performed.
PMID- 9764886
TI - Lymphocyte subsets and cytokines in adenoviral infection in children.
AB - To determine the distribution of major blood lymphocyte subsets we evaluated
blood lymphocytes by flow cytometry in adenovirus-infected infants aged 30-730 d.
In addition, interleukin-1-receptor antagonist, interleukin-10 and transforming
growth factor-beta1 were measured in serum by enzyme-linked immunosorbent assay.
According to clinical parameters, mechanical ventilation and outcome, infections
were classified as moderate (n = 15), severe (n = 11) and fatal (n = 12).
Controls were 13 healthy children. In severe and fatal infection, T cells
(CD5+/CD19-), NK effectors (CD16+), CD4+ T subset and B1 subset of B lymphocytes
(CD5+/CD19+) were all significantly decreased. CD8+ cells were decreased in
severe but not fatal cases. There was no difference in serum values of
interleukin-10; however, fatal cases had high interleukin 1-receptor antagonist
values. Interestingly, patients with moderate infection showed significantly
increased values of transforming growth factor-beta1. These results demonstrate
that life-threatening adenoviral infection is associated with marked
abnormalities in blood lymphocyte and cytokine profile.
PMID- 9764887
TI - Streptococcus pneumoniae isolated from a paediatric population: changes in 10
years.
AB - Susceptibility to penicillin, cefotaxime, erythromycin and chloramphenicol, as
well as serotypes of 100 Streptococcus pneumoniae strains isolated between 1984
and 1985, were compared to those of the same number of strains isolated between
1994 and 1995. The strains were obtained in Hospital Sant Joan de Deu, Barcelona,
and were thought to be the cause of a variety of infectious diseases in
paediatric patients attending this centre. Minimal inhibitory concentrations
(MICs) of penicillin were higher in strains of the second period (51% of
resistant strains during the first period vs 61% during the second one), as were
those of cefotaxime (12% vs 18%) and erythromycin (6% vs 36%), while
chloramphenicol MICs showed a light decrease (65% vs 46%). Serotypes 6, 19 and 23
were the most prevalent. Five new serotypes (4, 10, 18, 22 and 31) were detected
in 10 penicillin-susceptible strains during the second period. Because of the
increase in resistance to antibiotics commonly used in the treatment of systemic
and localized infections, therapeutic alternatives must be studied and suggested
in order to offer oral and percutaneous treatment for our children's infections
caused by pneumococci.
PMID- 9764888
TI - Open lung biopsy--successful diagnostic tool with therapeutic implication in the
critically ill paediatric population.
AB - Open lung biopsy (OLB) is an important diagnostic tool in children with immune
deficiency and/or chronic lung disease with diffuse pulmonary compromise. These
patients require a tailored therapeutic approach owing to their fragile status
and the side effects of unnecessary or inadequate treatment. Twenty-six patients
of mean age 5.6 y underwent 41 open lung biopsies in our centre between 1991 and
1995. Seventeen (65%) were immunocompromised (including 13 with malignancy) and 9
had other lung diseases. The biopsies were diagnostic in 25 patients (96%), and
complete clinical-pathological correlation was found in 11 (42%). A specific
infectious aetiology was detected in nine patients (35%), all of them
immunocompromised. Therapeutic changes were instituted on the basis of the biopsy
findings in 18 patients (69%). Two patients had postoperative complications
(prolonged pleural leak). We conclude that OLB is a safe diagnostic procedure
even in the critically ill child and should be employed without hesitation when
conventional methods fail to provide a definitive diagnosis to help redirect
therapy.
PMID- 9764889
TI - Renal impairment in patients with long-standing cyanotic congenital heart
disease.
AB - Nephropathy is known to occur in patients with long-standing cyanotic congenital
heart disease (CCHD). In order to assess the incidence, nature and degree of the
problem among such patients, discriminating urine analyses were performed in 26
patients with CCHD, with a mean age of 22 (10-42) y. Ten patients showed reduced
glomerular function, six of whom also had advanced glomerulopathy. Glomerular
filtration rates were below normal in half of the patients and occurred with
glomerular-type proteinuria in five, with tubular-type proteinuria in one and
without pathological proteinuria in four. An elevated haematocrit and duration of
cyanosis were identified as the main risks factors for the development of
glomerulopathy. The risk of developing glomerular lesions rose sharply during the
second decade of life. Nephropathy in CCHD is common and the dominant feature is
glomerular damage, which is related to the duration of cyanosis and the extent to
which the haematocrit is elevated.
PMID- 9764890
TI - Effect of umbilical arterial catheters on intestinal blood supply.
AB - Umbilical arterial catheters in the high position reduce the lumen of the aorta
and may thereby impair blood supply to the intestine. Thirty-two preterm and
three term infants were studied with an umbilical arterial catheter by colour and
duplex Doppler sonography. The diameter of the aorta at the level of the coeliac
axis was measured to calculate the reduction of the cross-sectional area of the
aorta by the catheter. Blood-flow velocities were measured in the coeliac axis,
the superior mesenteric artery and the anterior cerebral artery before and after
removal of the catheter. The umbilical arterial catheter reduced the cross
sectional area of the aorta by 3.4-27.2% (mean 10.1%). There was no difference
between blood-flow velocities in the coeliac axis and the superior mesenteric
artery before and after removal of the umbilical arterial catheter, indicating
that the catheter did not impair blood supply to the intestine.
PMID- 9764891
TI - Vitamin K in preterm breastmilk with maternal supplementation.
AB - Six healthy lactating mothers who gave birth to preterm infants at a median post
conceptional age of 29.5 (range 26-30) weeks were given 2.5 mg phylloquinone
(vitamin K1) orally daily for 2 weeks beginning at a median postconceptional age
of 31.5 (range 28-32) weeks. Phylloquinone was measured in the breastmilk daily
for 14 d. Trough plasma phylloquinone concentrations were also determined on four
occasions. Phylloquinone levels in the breastmilk increased from a baseline of 3
+/- 2.3 ng ml(-1) to 22.6 +/- 16.3 ng ml(-1) (mean +/- SD) after the first dose
(p < 0.05); a gradual increase was noted until phylloquinone levels reached a
plateau of 64.2 +/- 31.4 ng ml(-1) after the sixth daily dose.
PMID- 9764892
TI - "Idiopathic neutropenia" in very low birthweight infants.
AB - We employed a standardized investigative approach to evaluate four cases of
"idiopathic neutropenia" in very low birthweight infants. The evaluation included
maternal anti-neutrophil antibodies, a marrow aspiration, and a three-day trial
of recombinant granulocyte colony-stimulating factor (rG-CSF). All patients had
neutropenia at or shortly following delivery, and remained neutropenic (generally
<500/microl) for 1-9 weeks until rG-CSF was administered. Blood and bone marrow
studies in all 4 indicated that the neutropenia was: (i) the kinetic result of
diminished neutrophil production; (ii) not alloimmune; (iii) not cyclic; and (iv)
not associated with recognized inborn errors, bacterial or viral infections, or
medications. All responded to rG-CSF by transiently increasing their blood
neutrophils to normal, and the neutropenia resolved in all cases with time. It is
likely that "idiopathic neutropenia" in this population represents a common
phenotype of several different causes, rather than a single entity. Some cases,
perhaps the majority, will respond to a short course of rG-CSF administration.
PMID- 9764893
TI - Artificial neural network for predicting intracranial haemorrhage in preterm
neonates.
AB - Intraventricular haemorrhage (IVH) incidence is used to assess peri-/neonatal
therapy, and to make intra- and inter-hospital quality assessments. Unbiased
assessment is complicated by the amount of confounding factors. Is an artificial
neural network (ANN) able to early and accurately forecast the occurrence of
severe IVH in an individual patient? Is it superior to classic multiple logistic
regression? We conducted an observational study on pre-existing routine data.
Admission data were available from 890 preterm neonates (gestational age < 32
weeks, birthweight < 1500 g). Patients were randomly assigned to either a
training, or a validation set (50%/50%). Using the training set data an ANN was
trained. A second predictive model was developed by stepwise multiple logistic
regression analysis. Using the validation set input data both models delivered
estimates of the probability for severe IVH to occur in each individual patient.
Receiver operating characteristic (ROC) curves were used to compare prognostic
performance. The optimal ANN processed 13 input variables, whereas stepwise
logistic regression analysis only identified five independent predictor
variables. The area under the ROC curve was 0.935 for the ANN and 0.884 for the
logistic regression model (p = 0.001). Adjusted for 95%, 90%, 85%, 80% and 75%
specificity, the sensitivity of the ANN was significantly superior to that of the
logistic regression model. Due to its ability to give an accurate prognosis based
solely on admission data, a trained ANN qualifies as a tool for local quality
control.
PMID- 9764894
TI - Kangaroo mother care for low birthweight infants: a randomized controlled trial
in different settings.
AB - A randomized controlled trial was carried out for 1 y in three tertiary and
teaching hospitals, in Addis Ababa (Ethiopia), Yogyakarta (Indonesia) and Merida
(Mexico), to study the effectiveness, feasibility, acceptability and cost of
kangaroo mother care (KMC) when compared to conventional methods of care (CMC).
About 29% of 649 low birthweight infants (LBWI; 1000-1999 g) died before
eligibility. Of the survivors, 38% were excluded for various reasons, 149 were
randomly assigned to KMC (almost exclusive skin-to-skin care after
stabilization), and 136 to CMC (warm room or incubator care). There were three
deaths in each group and no difference in the incidence of severe disease.
Hypothermia was significantly less common in KMC infants in Merida (13.5 vs 31.5
episodes/100 infants/d) and overall (10.8 vs 14.6). Exclusive breastfeeding at
discharge was more common in KMC infants in Merida (80% vs 16%) and overall (88%
vs 70%). KMC infants had a higher mean daily weight gain (21.3 g vs 17.7 g) and
were discharged earlier (13.4 vs 16.3 d after enrolment). KMC was considered
feasible and presented advantages over CMC in terms of maintenance of equipment.
Mothers expressed a clear preference for KMC and health workers found it safe and
convenient. KMC was cheaper than CMC in terms of salaries (US$ 11,788 vs US$
29,888) and other running costs (US$ 7501 vs US$ 9876). This study confirms that
hospital KMC for stabilized LBWI 1000-1999 g is at least as effective and safe as
CMC, and shows that it is feasible in different settings, acceptable to mothers
of different cultures, and less expensive. Where exclusive breastfeeding is
uncommon among LBWI, KMC may bring about an increase in its prevalence and
duration, with consequent benefits for health and growth. For hospitals in low
income countries KMC may represent an appropriate use of scarce resources.
PMID- 9764895
TI - Community-based survey of paediatric diarrhoeal morbidity and home treatment
practices in Finland.
AB - To determine total diarrhoeal morbidity and current home case management
practices, a recall study was conducted among 345 mothers whose 406 children
under 5 y of age had had diarrhoea in the past 4 months. The seasonally adjusted
annual diarrhoea incidence rate was 0.48 episodes/child/y. For home treatment,
increased amounts of fluid were given in 93% and oral rehydration solution (ORS)
in 37% of cases. However, when given, ORS was diluted with other fluids in 41% of
cases. More than half (55%) of the children received increased or normal amounts
of food during the diarrhoeal episode, but 7% of the children were kept fasting
for at least 1 d. Use of antidiarrhoeal drugs was minimal (0.7%), but products
containing lactic acid bacteria were given in 44% of cases. Case management
practice in cases of diarrhoea at home have much improved during the last 20 y,
but are still not optimal.
PMID- 9764896
TI - Chlorinated contaminants, growth and thyroid function in schoolchildren from the
Aral Sea region in Kazakhstan.
AB - It has been shown by others that offspring of mothers who had been exposed to
dioxins and polychlorinated biphenyls (PCBs) during pregnancy have elevated
plasma levels of thyroid-stimulating hormone (TSH) for at least 3 months after
birth and reduced plasma levels of free and total thyroxine during the second
week after birth. As elevated levels of dioxins and PCB s can thus alter thyroid
hormone status, the relation between the levels of some polychlorinated organic
compounds in the blood lipids and growth and thyroid hormone status was studied
in 12 hospitalized schoolchildren from the Aral Sea region known to have high
exposure to such compounds. Their level of PCBs was two to four times higher than
in healthy Stockholm children. Their height was found to be lower than in healthy
Swedish children of the same age mean (SDS -0.52) and the body mass index (BMI)
was inversely correlated to the total concentrations of PCBs and
dichlorodiphenyltrichloroethane (DDT) and its metabolite
dichlorophenyldichloroethylene (DDE) in the blood lipids. As the levels of
insulin-like growth factor- were reduced to the same extent as the BMI it seems
likely that PCBs and DDT cause malnutrition as a result of malabsorption. None of
the children had any impairment of thyroid function, as revealed by the plasma
levels of TSH and thyroxine. Although the concentrations of beta
hexachlorocyclohexane (beta-HCH) and DDE were extremely high in some of the
children there was no relation between thyroid hormone status and the blood lipid
levels of PCBs, hexachlorocyclohexane and DDT. However, the concentration of
dioxins was not analysed.
PMID- 9764897
TI - Utilization of Child Health Services during the first 18 months of life: aspects
of health surveillance in Swedish preschool children based on information in
health records.
AB - The aim of this study was to evaluate some aspects of care given within the
preventive Child Health Services (CHS) during the first 18 months of life. A
national random sample performed on child health records of 172 Swedish preschool
children born between 1982 and 1987 was analysed regarding services recorded as
having been provided and used within and beyond the national programme of health
surveillance. Most families had made visits within the core programme of health
surveillance to an optimal or at least sufficient extent. First-time parents
visited the CHS more frequently than did more experienced parents. Procedures
within the programme, such as growth monitoring, hip examination and
immunizations, were documented to have been optimally performed on a majority of
the children. Conversely, screening for hearing impairment and assessment of
developmental milestones were performed less frequently, as were health
information and postnatal parental education. To improve the quality of care,
national recommendations ought to be more specific regarding both the performance
and the documentation of the service.
PMID- 9764898
TI - Changes in day care attendance rates and in the occurrence of adenoidectomies and
tympanostomies.
AB - The care of a child in a day care center is a marked risk factor for acute otitis
media. In a nationwide questionnaire survey we found that the rate of
tympanostomies and adenoidectomies was 59-67% higher for the children cared for
at a day care center before the age of 3 y. When the local authorities in Finland
at the beginning of 1990 were obliged by law to arrange day care for all children
under 3 y, the number of adenoidectomies performed on children at this age
increased by 30%.
PMID- 9764899
TI - Prone position may increase temperature around the head of the infant.
AB - Recommendations to adopt the supine position were followed by a dramatic decrease
of SIDS. But no explanation has been given for the association between SIDS and
the prone position nor for its decrease in the supine position. We report data on
an infant and a mannequin demonstrating an increase in temperature around the
head in the prone position. A 4-month-old boy presented an acute life-threatening
event related to temperature after febrile otitis despite treatment: 40.5 degrees
C, heart rate 280 bpm with circulatory failure and cardiorespiratory arrest
requiring resuscitation. There were no seizures. Blood and CSF cultures were
negative. The course under antibiotics was favourable. On d 3, we measured
temperature at several sites on and around the heat. Temperatures were higher in
the prone than in the supine position in pericephalic areas: +1 degrees C
(supracephalic), +2.5 degrees C (peritemporal), and +3.5 degrees C
(submandibular). In a thermoregulated room, we used a mechanically ventilated
mannequin of an infant. The prone position was also associated with an increase
in temperature around the head: +3.3 degrees C (supracephalic), +1.8 degrees C
(peritemporal), and +1.1 degrees C (submandibular). Changing from the supine to
prone position thus increased temperature around the head (infant and mannequin).
To our knowledge, this has not been reported before. SIDS is related to factors
modifying temperature status and environment. Furthermore, evacuation of heat is
mandatory for an infant. We think the increase in temperature around the head in
the prone position is due to the absence of convective fluxes, and speculate it
could impair thermolysis.
PMID- 9764900
TI - A case of vertical transmission of hepatitis A virus infection.
AB - We present a case of hepatitis A infection in a 2.5-month-old male who became
icteric after 18 d of birth. The diagnosis of hepatitis A was made by compatible
clinical symptoms, laboratory results and liver biopsy showing evidence of
hepatitis, and confirmed by detection of anti-HAV IgM antibodies. Because the
mother had an acute icteric hepatitis A 1 week before delivery, and the viraemic
phase of hepatitis A infection is very short, approximately 7 d, we suggest that
the infant was infected by his mother, before birth.
PMID- 9764901
TI - Congenital chylothorax in siblings.
AB - We describe two cases of congenital chylothorax in siblings with important
differences from previously described familial cases. Our findings support the
likelihood of an autosomal recessive inheritance in some cases of this condition,
rather than X-linked recessive inheritance, which has also been suggested.
Autopsy findings from one of these cases and others previously described suggest
that the pathophysiological mechanisms involved may be variable.
PMID- 9764903
TI - Is Chlamydia pneumoniae responsible for disease in children?
PMID- 9764902
TI - Rhabdomyolysis in European viper bite.
AB - The case of a child who presented with severe rhabdomyolysis associated with
renal failure after a viper bite is reported. Rhabdomyolysis is a serious
complication resulting from systemic envenomation and is uncommon after viper
bites in Europe. It may be due to oedema, myotoxic agents and haemorrhagic
factors and may be responsible for two types of potentially fatal complications,
i.e. acute renal failure and hyperkalaemia. The present case highlights the need
to investigate routinely for rhabdomyolysis after viper bites. Antivenom therapy
is recommended as soon as signs of envenomation are present, without waiting for
the onset of complications.
PMID- 9764904
TI - Long-term nonprogression in HIV infection: methodological issues and scientific
priorities. Report of an international European community-National Institutes of
Health Workshop, The Royal Society, London, England, November 27-29, 1995.
Scientific Coordinating Committee.
PMID- 9764905
TI - Association between a defective CCR-5 gene and progression to disease in HIV
infection.
AB - We measured the effect(s) of CCR-5 genotype on disease progression by studying
the frequency of a defective CCR-5 delta32 allele within a cohort of long-term
infected individuals. An elevated frequency of CCR-5 delta32 heterozygotes within
the cohort compared with a control population of blood donors was observed. An
association between progression rate and CCR-5 delta32 heterozygosity was
observed. Furthermore, analysis of proviral DNA V3 sequences from a subset of the
cohort predicted that the majority of individuals (39 of 44) were infected with
viruses predicted to utilize the beta-chemokine receptor CCR-5. The marked
association between CCR-5 genotype and disease progression observed in this study
may be a consequence of the predicted low frequency of CXCR-4-utilizing viruses
present within the selected cohort.
PMID- 9764906
TI - Primary intestinal epithelial cells can be infected with laboratory-adapted
strain HIV type 1 NDK but not with clinical primary isolates.
AB - Infectivities of HIV-1 primary isolates and laboratory-adapted strains were
compared in primary fetal enterocytes and the colonic epithelial cell line HT29.
Infection by two laboratory strains, HIV-1 NDK and HIV-1 NDK(A4), which were
adapted on CEM and HT29 cells, respectively, produced significant amounts of
virus in both target cell systems. Intestinal cells were resistant to infection
with HIV-1 primary isolates regardless of their genetic subtype or SI/NSI
phenotype. Biological properties of analyzed viruses rather than differences in
cultivation system seem to be responsible for differences between these in vitro
and ex vivo results.
PMID- 9764907
TI - Potent inhibition of HIV type 1 replication by an antiinflammatory alkaloid,
cepharanthine, in chronically infected monocytic cells.
AB - Cepharanthine is a biscoclaurine alkaloid isolated from Stephania cepharantha
Hayata and has been shown to have antiinflammatory, antiallergic, and
immunomodulatory activities in vivo. As several inflammatory cytokines and
oxidative stresses are involved in the pathogenesis of HIV-1 infection, we
investigated the inhibitory effects of cepharanthine on tumor necrosis factor
alpha (TNF-alpha)- and phorbol 12-myristate 13-acetate (PMA)-induced HIV-1
replication in chronically infected cell lines. Two chronically HIV-1-infected
cell lines, U1 (monocytic) and ACH-2 (T lymphocytic), were stimulated with TNF
alpha or PMA and cultured in the presence of various concentrations of the
compound. HIV-1 replication was determined by p24 antigen level. The inhibitory
effects of cepharanthine on HIV-1 long terminal repeat (LTR)-driven gene
expression and nuclear factor kappaB (NF-kappaB) activation were also examined.
Cepharanthine dose dependently inhibited HIV-1 replication in TNF-alpha- and PMA
stimulated U1 cells but not in ACH-2 cells. Its 50% effective and cytotoxic
concentrations were 0.016 and 2.2 microg/ml in PMA-stimulated U1 cells,
respectively. Cepharanthine was found to suppress HIV-1 LTR-driven gene
expression through the inhibition of NF-kappaB activation. These results indicate
that cepharanthine is a highly potent inhibitor of HIV-1 replication in a
chronically infected monocytic cell line. Since biscoclaurine alkaloids,
containing cepharanthine as a major component, are widely used for the treatment
of patients with various inflammatory diseases in Japan, cepharanthine should be
further pursued for its chemotherapeutic potential in HIV-1-infected patients.
PMID- 9764908
TI - Replication-defective HIV as a vaccine candidate.
AB - Live attenuated vaccines prepared from simian immunodeficiency virus (SIV) have
provided the best protective immunity in challenge experiments. In animals
vaccinated with attenuated SIV, immune responses may be elicited owing to
endogenous expression of native SIV proteins and/or antigen presentation in the
native replication site of virus. However, replication-competent viral vaccines
raise safety concerns for clinical trials in humans. To ensure the safety and
maintain the immunogenicity of a live, attenuated vaccine, we have developed a
replication-defective HIV pseudotyped with vesicular stomatitis virus G protein
(VSV-G). The polymerase gene of HIV was truncated to construct the replication
defective HIV. This pseudotyped HIV can infect many cell types, including human
and simian cells, and undergoes only one round of replication. Furthermore,
antibody immune response can be detected in mice immunized with VSV-G-pseudotyped
replication-defective HIV.
PMID- 9764909
TI - Production and characterization of SIV envelope-specific rhesus monoclonal
antibodies from a macaque asymptomatically infected with a live SIV vaccine.
AB - Five rhesus monoclonal antibodies (RhMAbs) were produced by rhesus EBV
transformation of peripheral blood B cells from a rhesus macaque that had been
asymptomatically infected with an attenuated, macrophage-tropic SIV strain, 17E
Cl. These MAbs recognized conformation-dependent epitopes on SIV gp120 and could
not be mapped using synthetic peptides. All five RhMAbs were able to neutralize
the vaccine strain and a heterologous isolate, SIV/DeltaB670. The RhMAbs did not
cross-react with HIV-2; by contrast, four human MAbs derived from an HIV-2
infected person were broadly cross-reactive with both SIV and HIV-2 gp120s. Cross
competition analysis indicated that the five RhMAbs could be placed in two groups
recognizing two nonoverlapping epitopes; while the HMAbs were placed in two
additional competition groups. Binding of the three group I RhMAbs (1.7F, 3.11B,
and 1.10A) as well as HMAb 17A was shown to be sensitive to specific amino acid
alterations in V4 occurring in natural env variants. The results of this study
demonstrate that RhEBV transformation provides a means to probe rhesus antibody
responses to SIV infection at the monoclonal level. RhMAbs will allow structural
and functional studies of envelope glycoprotein determinants that elicit
protective immune responses against SIV.
PMID- 9764910
TI - HIV peptide conjugated to heat-killed bacteria promotes antiviral responses in
immunodeficient mice.
AB - Enhancement of immunity in the setting of HIV infection is difficult owing to
loss of functional CD4+ T cells. The MHC class II-deficient mouse (II-/-)
environment simulates that of the immunocompromised HIV-infected individual,
since these mice have low CD4+ T cell numbers, defective CD4-dependent responses,
and are susceptible to opportunistic infection. This strain was used to test
whether heat-killed Brucella abortus (BA), covalently conjugated to the V3
peptide of HIV-1 (MN), could elicit anti-HIV responses. V3-BA, but not the T
dependent antigen V3-KLH, induced high levels of IL-12, IFN-gamma, and IL-10 mRNA
in both wild-type (WT) and II-/- mice within 24 hr of injection. V3-BA-treated,
but not V3-KLH-treated, II-/- mice developed serum IgG and IgA anti-V3
antibodies, with IgG2b and IgG3 as the predominant isotype. Viral neutralization
studies, using a syncytium inhibition assay, demonstrated that the antibodies
generated by V3-BA in II-/- mice were capable of neutralizing HIV. These
experiments demonstrate that a heat-inactivated bacterium such as BA, when used
as a carrier, can generate a cytokine environment that results in the production
of neutralizing antiviral antibodies in an immunodeficient host. Such strategies
could be important in the development of immunotherapies and vaccines for HIV-1
patients.
PMID- 9764911
TI - Functional and molecular characterization of human monoclonal antibody reactive
with the immunodominant region of HIV type 1 glycoprotein 41.
AB - The immunoreactivity, functional activity, and molecular features of a human
monoclonal antibody (HMAb), F240, from an HIV-1-infected individual have been
studied. Flow cytometric analysis demonstrated that F240 is reactive with cells
infected with a broad range of laboratory isolates but not with uninfected cells.
Reactivity of F240 is greatly enhanced by preincubation of infected cells with
soluble CD4, and to a much lesser extent, with F105, an HMAb reactive with the
CD4-binding site of gp120. This enhancement is temperature dependent, with
maximum enhancement observed at 37 degrees C, and suggests that the F240 epitope
may be more accessible after gp120 has bound to CD4 in vivo. Immunoblot analysis
reveals antigen specificity of F240 for gp41 or its precursor gp160. F240
specificity is mapped to the immunodominant region of the gp41 ectodomain by
Pepscan analysis. This epitope has been implicated in eliciting nonprotective
antibodies that enhance infection in the presence of complement. Consistent with
this, F240 failed to neutralize laboratory isolates and enhanced viral infection
in a complement-dependent manner. The F240 VH demonstrates extensive somatic
mutations compared with the product of its closest homologous germline gene VH3
3.11. Most amino acid substitutions occur in CDR2, characteristic of an antigen
driven response, and in FR3, a phenomenon observed in other anti-HIV-1 envelope
HMAbs. Primary structure analysis of the F240 heavy chain revealed strong
homology in the CDR domains to an HMAb (3D6) reactive with the same gp41 region,
which suggests that these HMAbs could define a potential human antibody
clonotype.
PMID- 9764912
TI - Molecular characterization of the envelope transmembrane glycoprotein of 13 new
human immunodeficiency virus type 1 group O strains from six different African
countries.
PMID- 9764913
TI - A novel glycoprotein 120 sequence from an HIV type 1 isolate of the A clade
identified in North Uganda.
PMID- 9764914
TI - HIV type 1 C2V3 env diversity among Belgian individuals.
PMID- 9764916
TI - Extreme founder effect in an HIV type 1 subtype A epidemic among drug users in
Svetlogorsk, Belarus.
PMID- 9764915
TI - The subtypes of HIV type 1 in Greece.
PMID- 9764917
TI - Introduction to histology of parasitic platyhelminthes.
PMID- 9764918
TI - Immunolocalization of schistosome proteins.
AB - This review discusses some of the recent advances in the characterization of
potential vaccine molecules against Schistosoma japonicum, utilizing microscopy
and immunocytochemistry methods. Microscopy has demonstrated the stage-specific
expression of the muscle protein paramyosin onto the parasite surface, an
important consideration as a vaccine target. Other potential vaccine component
proteins examined include glutathione S-transferase (GST) and fatty acid binding
protein (FABP); although not associated with the adult parasite surface, their
localization to internal structures such as lipid droplets and regions of the
female reproductive system have provided valuable insights into the biology of
the parasite. Localization of the transport protein SGTP (schistosome glucose
transporter protein) has demonstrated that the protein is more prevalent in the
juvenile stages of the parasite development. This further highlights the
diversity of the parasite life cycle. Using both light microscopy and
transmission electron microscopy, the localization of a number of schistosome
proteins has demonstrated the functions and significance of these proteins within
the parasite. Molecular localization studies are crucial in understanding how and
when a vaccine may work against the organism and may provide insights into which
can be used in the design of future vaccines.
PMID- 9764919
TI - Life history specializations of monogenean flatworms: a review of experimental
and microscopical studies.
AB - This review illustrates the use of experimental approaches combined with
microscopy to study the biology of monogenean parasites. Studies of feeding,
development, reproduction, and systematics have been based on gyrodactylids,
flatworms infecting teleost fishes. In a contrasting system involving an
amphibian host in a desert environment, analysis of adaptations to extreme
conditions has focused on Pseudodiplorchis americanus. The unusual reproductive
strategies, particularly the interactions between mother and offspring, are
highlighted for both monogeneans. Species of Gyrodactylus are viviparous,
maintaining up to three generations of embryos simultaneously in utero, and many
of their reproductive specializations are related to progenesis. Embryo nutrition
takes place via a metabolically-active syncytial uterine lining that has close
association with the parental gut. Microscopy has also proved an essential
adjunct to molecular studies of speciation and host specificity. P. americanus is
ovoviviparous and the adaptations for embryo maintenance are unique. The primary
keratin-type eggshell is replaced by a flexible secondary elastin capsule
produced by the uterus; parental nutrients are transferred through cytoplasmic
connections to the developing embryo. TEM has demonstrated unique adaptations of
P. americanus to its micro-environments, including secretion of tegumental
vesicles that provide protection from digestive enzymes during migration through
the host gut. This paper highlights the potential of monogeneans for studies of
fundamental biological principles.
PMID- 9764920
TI - Observations on the ultrastructure of the anterior adhesive areas and other
anterior gland cells in the monogenean Merizocotyle australensis (Monocotylidae)
from the nasal fossae of Himantura fai (Dasyatididae).
AB - The anterior adhesive areas of a monocotylid monogenean, Merizocotyle
australensis (Merizocotylinae), were investigated. They comprise 6 ventral
apertures in 2 groups of 3 arranged at the anterolateral margins of the head.
These regions are also well supplied with groups of cilia. Each aperture is 13.8
to 15.8 microm wide and contains multiple tubular projections that are covered
with microvilli through which open 2 types of secretory cell ducts that carry
either rod-shaped or spherical secretory bodies. The gland cell bodies that
produce these 2 types of secretions co-occur at the anterior end. The 2 types of
secretory bodies occur adjacent to one another and both are present in the
extruded adhesive. The membranes of rod-shaped bodies are retained in the
extruded glue. Rod-shaped bodies are 390 +/- 18 nm wide, at least 10.9 microm
long, and show 2 types of internal periodic banding: 10.6 nm and 143 +/- 3 nm.
The spherical vesicles are 130 +/- 6 nm in diameter and are electron-dense. A
third secretion is present in separate ducts that also open anteriorly but emerge
through the tegument between the ventral apertures. This secretion does not
appear to be part of the adhesive secretion. The bodies of the third secretion
are elongate, electron-dense, and 374 +/- 23 nm long. Inside the "lip" of the
aperture, general body tegument abuts tegument specific to the aperture. The
general body tegument is thicker, contains electron-dense vesicles, and has a
ridged surface devoid of microvilli. Where the 2 kinds of tegument meet, they are
connected by septate desmosomes.
PMID- 9764921
TI - Ultrastructure of the protonephridial system of the oncomiracidium of Encotyllabe
chironemi (Platyhelminthes, Monopisthocotylea).
AB - In the first electron-microscopic study of the protonephridium of a
monopisthocotylean oncomiracidium, flame bulbs, capillaries, and excretory
bladders of larval Encotyllabe chironemi were examined. Flame bulbs are formed by
a terminal and a proximal canal cell, whose cytoplasmic processes interdigitate
to form a typical weir. There are many internal leptotriches (cytoplasmic
outgrowths into the lumen of the flame bulb), but no (or very few) external
leptotriches. A septate junction, some surface lamellae, as well as numerous
vacuoles, some of which open into the canal lumen, are found in the wall of the
proximal canal. Lateral flames are present in the larger capillaries. Two
excretory bladders, each with a nucleus and containing many excretory
concrements, are located dorso-laterally. They open dorso-laterally through
narrow ducts lined by a thick wall containing electron-dense and lucent vacuoles.
Phylogenetic implications of the findings are discussed.
PMID- 9764922
TI - Ultrastructure of spermiogenesis and the spermatozoon of Vampirolepis microstoma
(Cestoda, Hymenolepididae), intestinal parasite of Rattus rattus.
AB - Spermiogenesis in Vampirolepis microstoma begins with the formation of a nuclear
cone and a differentiation zone. This is delimited at the front by arched
membranes, bordered by cortical microtubules, and contains two parallel
centrioles linked together at their bases by electron-dense, amorphous material.
The nuclear cone elongates, becomes filiform, and migrates into the spermatid
body. Later, one of the centrioles gives rise to a flagellum that grows at the
same pace as the cortical microtubules. Subsequently, 6 crested bodies form and
the old spermatid separates from the residual cytoplasm. The mature V. microstoma
spermatozoon is filiform and lacks mitochondria. Its anterior end exhibits six
crested bodies 100 to 200 nm thick of unequal lengths. The axoneme is of the
9+"1" pattern. The cortical microtubules are spiralized and make an angle of
about 20 to 30 degrees to the spermatozoon axis, except at their posterior
extremity where they become parallel to this axis. The nucleus is an electron
dense cord coiled in a spiral around the axoneme. The cytoplasm is slightly dense
but contains many electron-dense granules in regions III, IV, and V of the
spermatozoon. The presence of centrioles linked together at their bases by
electron-dense material has never, to our knowledge, been reported in a
Platyhelminth. Likewise, a nuclear migration, right from the beginning to the end
of spermiogenesis, has never been described in a cestode. In addition, we observe
for the first time the existence of six crested bodies in a cestode from a
Mammal.
PMID- 9764923
TI - Testicular microvascularization in the common tree shrew (Tupaia glis) as
revealed by vascular corrosion cast/SEM and by TEM.
AB - Testicular angioarchitecture in lower primates has not been established and the
route of androgens from Leydig cells entering the systemic circulation is still a
matter of controversy. In the present study, the common tree shrew (Tupaia glis)
was used as the model for vascular corrosion cast/SEM and conventional TEM
studies. With vascular corrosion cast/SEM, it was revealed that while coursing in
the spermatic cord, the testicular artery convoluted and gave off branches to
supply the epididymis, the coverings of the spermatic cord and the pampiniform
plexus. Upon approaching the testis, it encircled the organ, then penetrated into
the testicular parenchyma near the rostro-medial pole before further dividing
into arterioles that gave rise to capillary plexuses looping around the
seminiferous tubules. These capillaries converged into the intratesticular
venules, then into larger venules on ventral and dorsal surfaces of the testis
and finally into the collecting veins on medial and lateral borders of the
testis. In addition, the capillaries in the central or medullary portion of the
gland collected the blood into the medullary venules and central (medullary)
vein, respectively. The collecting veins as well as central vein joined together
before dividing into pampiniform plexus. With transmission electron microscopy,
the capillaries in the testis were shown to be of the thick basement membrane and
continuous type. The Leydig cells were found adjacent to lymphatic vessels among
the seminiferous tubules. This structure is compatible with the idea that most of
the androgens drain into the lymphatic vessels rather than into the capillaries.
PMID- 9764924
TI - Immunohistochemical localization of surfactant apoproteins in usual interstitial
pneumonia associated with pulmonary carcinoma.
AB - Surfactant apoproteins A and B (SP-A and SP-B) are antigenic determinants of
pulmonary surfactant complexes. The role and functional significance of these
proteins are largely unknown and the pattern of expression is probably related to
the functional maturation of type II pneumocytes. Differential expression of SP-A
and SP-B was reported in the developing human lung but little is known of their
expression in the chronic injury. We studied 5 surgical cases of usual
interstitial pneumonia (UIP) associated with carcinoma to evaluate the expression
of pulmonary surfactant apoproteins. These cases were immunohistochemically
examined by the streptavidin-biotin complex method using monoclonal antibodies HS
1 and HS-2 against pulmonary surfactant apoprotein A (SP-A) and B (SP-B),
respectively. In UIP, SP-B was expressed strongly in type II pneumocytes and
Clara cells but bronchiolar epithelium and metaplastic squamous cell lines in the
honeycomb lesion were non-reactive. SP-A showed a similar pattern but much weaker
reactivity when compared to that of SP-B. Type II pneumocytes in normal lung
tissue exhibited weak immunoreactivity and no difference in the intensity of
staining between SP-A and SP-B. Neither carcinomatous area nor metaplastic lining
cells at honeycomb lesion show immunoreactivity to SP-A and SP-B. These results
suggest that type II pneumocytes in the UIP are functionally immature in their
expression of the apoprotein types and the metaplastic squamous cells or
neoplastic transformed cells do not have molecular characteristics of type II
pneumocytes.
PMID- 9764925
TI - Development of a small-scale bioreactor for drug metabolism studies maintaining
hepatospecific functions.
AB - 1. The aim of the study was the development of a small-scale liver cell
bioreactor maintaining tissue monoxygenase activity and hepatospecific activities
over at least 2 weeks. 2. For characterization the antihypertensive drug urapidil
was used as a model compound to study maintenance of metabolic activity. Tissue
specific parameters assessed included urea and albumin secretion as well as
cellular integrity. The problem of the use of serum in bioreactor cultures is
addressed. 3. Bioreactor runs could be performed in serum- and lactate-free
cultures with a joint recovery of oxidative biotransformation capacity for
urapidil as well as tissue-specific markers. LDH release was reduced with older
cultures. Fibronectin was shown as a contributing factor for cell attachment. 4.
In the present study the design and function of a modular, small-scale-type
bioartificial liver cell culture model is thus described lending itself for drug
metabolism studies but maintaining also typical hepatospecific properties.
PMID- 9764926
TI - Induction of pulmonary CYP1A1 by nicotine.
AB - 1. We have examined the catalytic activities (7-ethoxyresorufin O-deethylase
[EROD] and 7-methoxyresorufin O-demethylase [MROD]), protein levels (Western blot
analysis) and mRNA levels (Northern blot analysis) of cytochrome P4501A (CYP1A1
and CYP1A2) in the lung, liver and kidney following a single 2.5 mg/kg (15.4
micromol/kg) subcutaneous dose of nicotine to the female Sprague-Dawley rat. 2.
Only in lung microsomes was EROD activity significantly induced by nicotine
treatment. The activity increased 4.4-fold at 6 h after treatment relative to
controls, peaked at 12 h at 14.7-fold the control activity and returned to near
control level at 24 h. 3. In parallel with EROD activity, CYP1A1 immunoreactive
protein abundance was altered significantly by nicotine treatment only in the
lung, peaking at 12 h and decreasing towards control levels thereafter. 4.
Following subcutaneous nicotine treatment, CYP1A1 mRNA was detectable in the lung
at 6 and 12 h but not at 24 h, was slightly elevated in the kidney at 12 h and
was detectable in the liver only at the 12-h point. CYP1A2 immunoreactive protein
and its mRNA were detectable only in the liver, and their levels were not
affected significantly by nicotine pretreatment. 5. Nicotine affected the binding
of Hepa 1c1c7 cytosolic protein to a CYP1A1 xenobiotic response element in a gel
mobility shift assay, suggesting involvement of the aryl hydrocarbon receptor and
transcriptional activation in CYP1A1 induction by the chemical. 6. Inhaled
nicotine also induced pulmonary EROD activity, and the induction by either
inhaled or injected nicotine was more pronounced in the male than in the female
rat. 7. The findings show that nicotine is a potent, rapid but transient inducer
of CYP1A1 in the rat lung and suggest that the alkaloid is a likely contributor
to CYP1A1 induction by cigarette smoke.
PMID- 9764927
TI - Effects of propofol on human hepatic microsomal cytochrome P450 activities.
AB - 1. The potential of propofol to inhibit the activity of major human cytochrome
P450 enzymes has been examined in vitro using human liver microsomes. Propofol
produced inhibition of CYP1A2 (phenacetin O-deethylation), CYP2C9 (tolbutamide 4'
hydroxylation), CYP2D6 (dextromethorphan O-demethylation) and CYP3A4
(testosterone 6beta-hydroxylation) activities with IC50 = 40, 49, 213 and 32
microM respectively. Ki for propofol against all of these enzymes with the
exception of CYP2D6, where propofol showed little inhibitory activity, was 30, 30
and 19 microM respectively for CYPs 1A2, 2C9 and 3A4. 2. Furafylline,
sulphaphenazole, quinidine and ketoconazole, known selective inhibitors of CYPs
1A2, 2C9, 2D6 and 3A4 respectively, were much more potent than propofol having
IC50 = 0.8, 0.5, 0.2 and 0.1 microM; furafylline and sulphaphenazole yielded Ki =
0.6 and 0.7 microM respectively. 3. The therapeutic blood concentration of
propofol (20 microM; 3-4 microg/ml) together with the in vitro Ki estimates for
each of the major human P450 enzymes have been used to estimate the extent of
cytochrome P450 inhibition, which may be produced in vivo by propofol. This in
vitro-in vivo extrapolation indicates that the degree of inhibition of CYP1A2,
2C9 and 3A4 activity which could theoretically be produced in vivo by propofol is
relatively low (40-51%); this is considered unlikely to have any pronounced
clinical significance. 4. Although propofol has now been used in > 190 million
people since its launch in 1986, there are only single reports of possible drug
interactions between propofol and either alfentanil or warfarin. Consequently, it
is difficult to conclude from either the published literature or the ZENECA
safety database whether there is any evidence to indicate that propofol produces
clinically significant drug interactions through inhibition of cytochrome P450
related drug metabolism.
PMID- 9764928
TI - Hydrogen atom abstraction of 3,5-disubstituted analogues of paracetamol by
horseradish peroxidase and cytochrome P450.
AB - 1. The formation of free radicals during enzyme catalysed oxidation of eight 3,5
disubstituted analogues of paracetamol (PAR) has been studied. A simple
peroxidase system as well as cytochrome P450-containing systems were used.
Radicals were detected by electron spin resonance (ESR) on incubation of PAR and
3,5-diCH3-, 3,5-diC2H5-, 3,5-ditC4H9-, 3,5-diOCH3-, 3,5-diSCH3-, 3,5-diF-, 3,5
diCl- and 3,5-diBr-substituted analogues of PAR with horseradish peroxidase in
the presence of hydrogen peroxide (H2O2). Initial analysis of the observed ESR
spectra revealed all radical species to be phenoxy radicals, based on the absence
of dominant nitrogen hyperfine splittings. No radicals were detected in rat liver
cytochrome P450-containing microsomal or reconstituted systems. 2. To rationalize
the observed ESR spectra, hydrogen atom abstraction of PAR and four of the 3,5
disubstituted analogues (3,5-diCH3-, 3,5-diOCH3-, 3,5-diF- and 3,5-diCl-PAR) was
calculated using ab initio calculations, and a singlet oxygen atom was used as
the oxidizing species. The calculations indicated that for all compounds studied
an initial hydrogen atom abstraction from the phenolic hydroxyl group is favoured
by approximately 125 kJ/mol over an initial hydrogen atom abstraction from the
acetylamino nitrogen atom, and that after hydrogen abstraction from the phenolic
hydroxyl group, the unpaired electron remains predominantly localised at the
phenoxy oxygen atom (+/-85%). 3. The experimental finding of phenoxy radicals in
horseradish peroxidase/H2O2 incubations paralleled these theoretical findings.
The failure to detect experimentally phenoxy radicals in cytochrome P450
catalysed oxidation of any of the eight 3,5-disubstituted PAR analogues is more
likely due to the reducing effects that agents like NADPH and protein thiol
groups have on phenoxy radicals rather than on the physical instability of the
respective substrate radicals.
PMID- 9764929
TI - Structural determination of metabolites of S-1153, a new, potent, non-nucleoside,
anti-HIV agent in rat liver microsomes.
AB - 1. S-1153, a non-nucleoside agent that is under development in the USA as a new
anti-HIV agent, has potent antiviral activity based on the inhibition of reverse
transcriptase. 2. S-1153 was incubated with rat liver microsomes and NADPH, and
seven metabolites were formed. The main metabolites were identified as the S
oxide, N-oxide and sulphone of S-1153. 3. Two other minor metabolites were
assumed to be S-1153 hydroxylated on the isopropyl moiety. 4. Our findings
confirmed the existence of at least three oxidative metabolic pathways of S-1153.
PMID- 9764930
TI - Pharmacokinetic properties and oral bioavailabilities of difloxacin in pig and
chicken.
AB - 1. Pharmacokinetic properties of difloxacin have been studied in pig and chicken
after intravenous and oral administration. 2. The serum concentrations of
difloxacin in pig and chicken after intravenous administration were best
described by a two-compartment open model, giving distribution half-lives of 0.50
and 0.66 h and elimination half-lives of 7.92 and 4.10 h for pig and chicken
respectively. The steady-state distribution volumes were 1.70 and 3.06 l/kg for
pig and chicken respectively. 3. After oral administration of 5 mg/kg to pig and
chicken, the serum concentrations reached maximal levels of 3.61 and 0.96
microg/ml respectively at 1.25 and 1.40 h. The elimination half-lives were 11.8
and 7.35 h for pig and chicken respectively. 4. The bioavailabilities of
difloxacin were calculated as 93.7 (pig) and 86.9% (chicken).
PMID- 9764932
TI - Type-specific serological testing for herpes simplex infection.
PMID- 9764931
TI - In vitro toxicity of zamifenacin (UK-76,654) and metabolites in primary
hepatocyte cultures.
AB - 1. We compared the sensitivities of primary hepatocytes from rat, dog and monkey
to zamifenacin and two major metabolites, the methylenedioxy ring-opened
catechol, UK-80,178 and its methylated product, UK-82,201. Toxicity was
determined both via neutral red uptake and enzyme leakage data. 2. Canine
hepatocytes were most sensitive to the cytotoxic effects of zamifenacin during 24
h exposure. Significant decreases in medium concentrations of zamifenacin in the
presence of primary hepatocytes verified cellular uptake during the initial 2-h
incubation. All three cell types were much more sensitive to UK-82,201 than to
the catechol metabolite or parent drug. 3. The rapid onset of cytotoxicity
indicated by elevations of alanine aminotransferase (ALT), aspartate
aminotransferase (AST) and other markers in the medium after UK-82,201 exposure,
the delayed but substantial cytotoxic response to the parent drug which was
suggestive of biotransformation to a reactive moiety, in vivo and in vitro drug
metabolism results and subacute toxicology data suggest that dog may more
effectively transform zamifenacin into UK-82,201, which is relatively
hepatotoxic. 4. Because the catechol was generally less toxic than the O
methylated product, species that eliminate zamifenacin primarily as the catechol
or its conjugate may be less affected by the potential hepatotoxicity of the
methylated product. Our studies show that dog is the most sensitive species due
to metabolism of the common catechol metabolite. The low incidence of potential
hepatotoxicity in the clinic points to rare but important differences in the
metabolism of Zamifencin. We conclude that the findings in dog were not
predictive of subsequent effects in man.
PMID- 9764933
TI - Sexually transmitted organisms in children and child sexual abuse.
PMID- 9764934
TI - Financing HIV service provision in England: estimated impact of the cost of
antiretroviral combination therapy.
AB - The objective of this study was to provide population-based estimates on the cost
of HIV service provision in England and the use of dual or triple antiretroviral
combination therapy. Contemporary cost estimates of treating HIV-infected
individuals by clinical stage of HIV infection (indexed to 1995/96 prices) were
linked to the number of diagnosed HIV-infected individuals using statutory
medical services in England during 1996. Two cost measures were used: the first
one was based on average hospital prices derived from a number of English HIV
units. These results were compared with those estimated using standard unit costs
obtained through specific costing studies performed at a national HIV referral
centre. Overall annual expenditure on HIV service provision was estimated for
different treatment scenarios as was expenditure by clinical stage of HIV
infection. Using hospital prices, in 1996 the total annual cost estimate for HIV
service provision amounted to pound sterling 131 m (range pound sterling 83 m to
pound sterling 233 m), or pound sterling 150 m (95% CI pound sterling 126 m to
pound sterling 173 m) using standard costs, if all patients with HIV disease were
treated with AZT monotherapy. For all eligible patients to be treated with dual
therapy, cost estimates amounted to pound sterling 161 m (range pound sterling
126 m to pound sterling 173 m) per year using hospital prices or pound sterling
180 m (95% CI pound sterling 156 m to pound sterling 203 m) when using standard
cost estimates, while for triple therapy annual estimated expenditure amounted to
pound sterling 204 m per year (range pound sterling 157 m to pound sterling 306
m) when using hospital prices or pound sterling 223 m (95% CI pound sterling 199
m to pound sterling 246 m) using standard costs. Increasingly costs will be more
evenly distributed across the 3 stages of HIV infection, with a greater
proportion of costs generated by HIV-infected individuals before the onset of
AIDS. Using non-standardized hospital prices may systematically underestimate the
real cost of service provision. Monitoring prospectively the use, cost and
outcome of HIV service provision in a standardized format will provide
information on the actual cost impact over the next 2-3 years of combination
therapy compared with the scenario-based estimates produced in this paper.
PMID- 9764935
TI - Bronchopulmonary Kaposi's sarcoma in 106 HIV-1 infected patients.
AB - The objectives of this study were to describe the clinical and radiological
features at presentation, and the natural history of HIV-related bronchopulmonary
Kaposi's sarcoma. A retrospective review of medical records and chest radiographs
was performed in 106 HIV-infected homosexual men with bronchopulmonary Kaposi's
sarcoma diagnosed at bronchoscopy between September 1988 and November 1994. The
majority of patients had evidence of advanced HIV disease at diagnosis (median
CD4 cell count was 15 x 10(6)/l, range 0-288), and 93% had had a diagnosis of
cutaneous Kaposi's sarcoma for a median duration of 11 months prior to diagnosis
of their bronchopulmonary disease. The most frequent symptoms at presentation
were cough (92%), dyspnoea (69%), pleuritic pain (20%), haemoptysis (13%) and
wheezing (10%). The most common radiological finding in 73% of our series was of
poorly defined and confluent opacities, with predominant middle and lower zone
involvement. Median survival was 4 months (range 0-37 months) from diagnosis and
9 months (range 1-25) from the onset of symptoms. Treatment with either
chemotherapy or radiotherapy was associated with a significantly reduced risk of
death (hazards ratio (HR)=0.48, 95% CI=0.26-0.87). Factors associated with a poor
survival, after adjustment for treatment effect were older age (HR=1.79, 95%
CI=1.22-2.84) for each 10-year increase in age; a history of pleuritic pain
(HR=2.97, 95% CI=1.39-6.32); presence of pleural effusion on X-ray (HR=2.01, 95%
CI=1.13-3.59) and a prior diagnosis of cutaneous Kaposi's sarcoma (HR=1.8, 95%
CI=1.00, 3.24). Bronchopulmonary Kaposi's sarcoma occurs mainly in patients with
advanced HIV disease and a prior history of cutaneous disease. Survival is poor,
and adverse prognostic factors include older age at diagnosis and the presence of
pleural disease.
PMID- 9764936
TI - Vulvovaginal candidiasis in female sex workers.
AB - Vulvovaginal candidiasis is a frequent inflammatory process in women but it has
not been widely studied in female sex workers (FSWs). To estimate the frequency
of Candida species infection in FSWs and to identify related risk factors and
clinical findings, we carried out a retrospective study of 1923 FSWs over 11
years. We also performed a prospective study of 163 consecutive FSWs with a
history of candidiasis during a 4-year period. Candida species were isolated in
1967 samples (18.5% of the total). Candida albicans (89.3%) was the most frequent
species, followed by Candida glabrata (2.7%), Candida parapsilosis (1.2%) and
Saccharomyces cerevisiae (0.4%). In the prospective study of 163 patients, we
found vaginal discharge in 76.1% of cases, soreness in 52.1% and vulval pruritus
in 32.5%. We identified 12 patients (7.4%) with recurrent vulvovaginal
candidiasis. No statistical difference was found between recurrent vulvovaginitis
and the use of oral contraceptives, oral sex, tight-fitting clothing and
synthetic underwear. FSWs have the same prevalence of candidiasis as other groups
of women described in published literature. The proportion of albicans and non
albicans species does not differ between women with recurrent and non-recurrent
vulvovaginal candidiasis (VVC).
PMID- 9764937
TI - Clinical and in situ cellular responses to Haemophilus ducreyi in the presence or
absence of HIV infection.
AB - We aimed to determine if the clinical and histological features of chancroid are
altered by HIV infection. Male patients presenting to the Nairobi special
treatment clinic with a clinical diagnosis of chancroid were eligible for the
study. A detailed history, physical examination, swabs for Haemophilus ducreyi
culture and blood for HIV serology, syphilis serology and CD4 counts were
obtained from all patients. Punch biopsies from an ulcer were obtained from 10
patients and either fixed in 10% formalin or snap frozen in Optimum Cutting
Temperature (OCT) medium compound at -70 degrees C. Patients were treated with
erythromycin and followed for 3 weeks. Chi-square and Student's t-test were used
to determine if the clinical and laboratory features of chancroid differed
between HIV-seropositive and seronegative individuals. Cox regression survival
analysis was used to determine if HIV infection altered cure rates of chancroid
at 21 days. Immunohistochemical staining was performed using lymphocytic and
macrophage markers and tissue sections were analysed by 2 pathologists in a
blinded manner. Between February and November 1994, 109 HIV-seropositive and 211
HIV-seronegative individuals were enrolled in the study. HIV patients had ulcers
of longer duration than HIV-seronegative patients (P=0.03). Although cure rates
were similar at 3 weeks, HIV patients had lower cure rates at 1 week (23% v 54%,
P=0.002). A dense interstitial and perivascular inflammatory infiltrate extending
from the reticular to deep dermis was present in all biopsies. This consisted of
equal amounts of CD4 and CD8 T-lymphocytes as well as macrophages. The
histological and immunohistochemical picture was identical for HIV-positive and
negative patients. HIV infection slows the healing rates of chancroid ulcers
despite appropriate antibiotic therapy. This clinical difference cannot be
attributed to an altered histopathological response to HIV infection. Additional
studies are needed to elucidate the mechanisms responsible for this finding.
PMID- 9764938
TI - Efficacy of surgical and/or podophyllotoxin treatment against flat acetowhite
penile human papillomavirus associated lesions.
AB - In order to investigate the efficacy of treatment modalities favoured by us
against flat acetowhite penile human papillomavirus (HPV)-induced lesions, we
studied retrospectively standardized medical records of 81 men who had been
treated for this condition. The patients were treated surgically with diathermy
(n=32) or with a combination of both chemical (topical application of
podophyllotoxin) and surgical treatment (n=49). The mean number of clinic visits
was 9.1 (range 1-19), during a follow-up time of mean 30.9 (range 1-104) months
for 78 of the men, 3 of them only visited the clinic once. The mean time for cure
was 19.9 (range 0-103) months. Only 12 (15%) patients were healed after one
single treatment session, while as many as 50 (62%) required > 4 sessions. The
mean number of surgical treatment sessions required for cure differed
significantly (P=0.0006) between the previously treated patients who needed a
mean of 5.6 treatment sessions, compared to the previously untreated men who
required surgery a mean of 3.4 times for cure.
PMID- 9764939
TI - Emergency unit care of sexually transmitted infections.
AB - The aim of the study was to assess provisions for management of sexually
transmitted infections (STIs), emergency contraception and pregnancy test in UK
emergency departments. Postal questionnaires were sent to all consultant-led
emergency departments in the UK in January 1996. The response rate was 64%. Most
departments made direct referrals to genitourinary medicine (GUM) clinics and
most had access to appropriate clinics. While 55% had facilities for diagnosis of
at least one of the 3 common STIs (Chlamydia trachomatis, Neisseria gonorrhoeae
and herpes simplex), only 6.25% had facilities for all 3. A minority of units
provided training in the management of STIs. Emergency physicians should be
trained in the early management of STIs and a coordinated working relationship
should be developed between emergency and GUM departments to provide optimal
sexual health care.
PMID- 9764940
TI - Cytomegalovirus pp65 antigenaemia as an indicator of end-organ disease in AIDS.
AB - We aim to assess the usefulness of the cytomegalovirus (CMV) pp65 antigenaemia
test, also called the CMV direct antigen test (DAT), in the management of
patients with advanced human immunodeficiency virus (HIV) infection; we studied
all patients who had pp65 assays between 8 September 1995 and 30 August 1996.
Twenty-three patients had 31 tests. The mean CD4 cell count was 20/mm3. The tests
were negative in 16 patients, of whom 12 have not developed CMV end-organ disease
after a mean follow up of 114 days (range 14-269 days), whilst the remaining 4
patients had previously treated CMV disease. Eleven patients had positive tests:
4 had active CMV disease, 2 subsequently developed CMV retinitis, 2 died within a
fortnight of multi-drug resistant tuberculosis (MDR-TB), one was lost to follow
up and 2 have remained disease-free. This test has a positive predictive value of
43% and a negative predictive value of 94%, Fisher's exact test P=0.03. The pp65
antigenaemia assay can be performed in a standard virology laboratory avoiding
the problems associated with polymerase chain reaction (PCR), a result is
available within 5 h, and it is semi-quantifiable. However, a large prospective
study is required to determine the comparative value and roles of the pp65
antigenaemia assay and DNA PCR in the management of CMV disease, especially with
regard to the use of primary prophylaxis and pre-emptive therapy.
PMID- 9764941
TI - HIV infection and asymptomatic sexually transmitted infections in a rural South
African community.
AB - The objective was to determine the prevalence of HIV and other sexually
transmitted infections (STIs) in a rural community. A population-based survey of
adults in 110 homesteads was conducted in 1995. A questionnaire on demographics,
sexual practices and history of STDs was administered. Neisseria gonorrhoeae and
Chlamydia trachomatis infections were detected using ligase chain reaction (LCR)
assay of urine. The seroprevalence of syphilis rapid plasma reagin (RPR) and
Treponema pallidum haemagglutination assay (TPHA) and HIV infection (ELISA) was
determined. Among 259 subjects the prevalence of HIV was 10.5%, N. gonorrhoeae
4.5%, C. trachomatis 6.1% and active syphilis 8.8%. All infections were
asymptomatic. Forty per cent of sexually active men had more than one concurrent
sexual partner. Only 14% of subjects had ever used condoms. The STI epidemic is
being promoted by high levels of asymptomatic infections, high partner
concurrency and low condom use.
PMID- 9764943
TI - Renal calculi developing de novo in a patient taking saquinavir.
PMID- 9764942
TI - The availability and cost of antibiotics for treating PID in the Central Region
of Ghana and implications for compliance with national treatment guidelines.
AB - The availability and cost of antibiotics for treating pelvic inflammatory disease
(PID) were assessed in 17 drug-dispensing outlets in 5 districts of the Central
Region, Ghana. The outlets included the dispensaries of 2 regional and 4 district
hospitals, 4 privately-owned pharmacies and 7 chemical seller shops. The most
common antibiotics available, including co-trimoxazole, metronidazole,
benzylpenicillin, amoxycillin, chloramphenicol and gentamicin, were also the
lowest-priced drugs. Conversely, the most expensive antibiotics including
ceftriaxone, ciprofloxacin, cefuroxime and spectinomycin, were also the least
commonly available. Recommended anti-gonococcal antibiotics (ciprofloxacin,
ceftriaxone) may not be prescribed if they are not available in the districts.
PMID- 9764945
TI - Cervical smear: is screening of teenagers justified?
PMID- 9764944
TI - Redefining AIDS: case exemplified by Penicillium marneffei infection in HIV
infected people in Hong Kong.
PMID- 9764946
TI - Study Site Coordinator/Research Nurse.
PMID- 9764947
TI - Epidemiology, demographics, and genetics of sarcoidosis.
AB - Epidemiological knowledge of sarcoidosis is based mainly on studies performed
more than 30 years ago. These early case-control studies produced some
interesting risk factor-disease associations, but a clear causative mechanism in
sarcoidosis remains unknown. Studies in military and veteran populations showed a
clear preponderance of sarcoidosis in African Americans compared with Caucasians.
Our recent sarcoidosis incidence study in a racially heterogeneous population
found African Americans at three- to fourfold greater risk, which was less than
the 10 to 17 times greater risk previously reported. Females are consistently
found at greater risk than males, although the relative risk difference generally
does not exceed two. The striking racial differences and numerous reports of
familial clustering suggest genetic susceptibility. We have found that familial
sarcoidosis is almost three times more common in African-American (17%) than
Caucasian cases (6%). Future genetic studies can benefit from the extensive
catalog of candidate genes that is emerging from the human genome project. The
epidemiological evidence to date strongly suggests that studies seeking causes
for sarcoidosis need to consider both environmental and genetic risk factors to
be successful because the two likely interact with each other to produce disease.
PMID- 9764948
TI - Involvement of T cells and alterations in T cell receptors in sarcoidosis.
AB - Sarcoidosis is recognized to be a multisystem granulomatous disease characterized
by activated, cytokine-producing T cells and macrophages at sites of
inflammation. The purpose of this article is to review new evidence concerning
the role of T cells in sarcoidosis. Recent work on the molecular structure and
repertoire of T cell receptor genes in sarcoidosis provide direct evidence that
sarcoidosis is characterized by selective expansions of oligoclonal populations
of T cells at sites of inflammation, consistent with local antigen-driven immune
responses. In addition, data on cytokine production in sarcoidosis indicate that
tissue inflammation is dominated by expression of type 1 (T helper 1) cytokines
such as interferon-gamma and interleukin-12 that, in keeping with experimental
models of granulomatous diseases, likely orchestrate the granulomatous response.
These studies offer new insight into the molecular mechanisms of granuloma
formation in sarcoidosis and provide a framework for developing new therapeutic
strategies for the treatment of this disease.
PMID- 9764949
TI - Cytokines in sarcoidosis.
AB - Although the cause of sarcoidosis is still unknown, the combination of the
characteristic morphologic aspect and the immunohistologic pattern of the sarcoid
granulomatous lesions suggest that they are the result of an antigen-driven
process. In particular, sarcoid granuloma is considered to be the consequence of
an exaggerated immunological response against an undefined antigen which has
persisted at the sites of disease involvement. Taking advantage of the
availability of pure recombinant cytokines and molecular probes for cytokines and
their receptors, in the last few years it has been possible to keenly study the
involvement of several cytokines in the pathologic changes associated with
sarcoidosis. The purpose of this review is to summarize the interactions between
cytokines and their receptors which define regulatory networks ultimately
contributing to the sarcoid granuloma formation at sites of disease activity.
After a concise overview of the main cytokines involved in the sarcoid
inflammatory response, we will briefly discuss the biological effects of Th1 and
Th2 cytokines in sarcoid lung and then concentrate on the importance of the local
production of those molecules whose release has been recently shown within the
lung of patients with sarcoidosis, such as interleukin-12, interleukin-15, and
chemokines. Furthermore, we will focus the discussion on the cytokines which,
pivotal to the activation of the host defenses, may contribute to lung damage and
the consequent lung fibrosis. The final section of this article reviews the lung
release of cytokines in the context of recent hypotheses claiming microbial
pathogens as putative causative agents of sarcoidosis.
PMID- 9764951
TI - Kveim antigen: what does it tell us about causation of sarcoidosis?
AB - This article explores the role of the Kveim-Siltzbach (KS) test in finding the
cause of sarcoidosis. Experimental granulomas are formed by a T-cell mediated
immunologic response to particulate agents which resist degradation and persist
in tissues for prolonged periods. There is no animal model for human sarcoidosis.
However, the KS test is an in vivo model of sarcoidosis. KS homogenates incite a
tissue response in patients with sarcoidosis histologically identical to disease
caused granulomas. The suspensions are particulate and maintain activity when
exposed to a variety of chemical and physical stresses. Studies of the monocyte
and T-cell host response confirm that KS reagent provokes a sarcoidosis-like
antigen driven granuloma. KS suspensions contain an antigen(s) that incite a
granuloma identical with that occurring in sarcoidosis. Identification of the
active principle in KS suspensions should aid in the search for the cause of
sarcoidosis.
PMID- 9764950
TI - The role of mycobacteria in the pathogenesis of sarcoidosis.
AB - The pathogenesis of sarcoidosis has intrigued clinicians since the first
descriptions of the disease, and a number of causes have been proposed. Among the
candidate agents, the possible role of mycobacterial infection in the
pathogenesis of sarcoidosis has attracted by far the most attention. The purpose
of this review is to summarize current evidence concerning the role of
mycobacterial infection in sarcoidosis. First, the similarities in clinical and
histological features of tuberculosis and sarcoidosis that have raised suspicion
that mycobacterial infection could be involved in the pathogenesis of sarcoidosis
are discussed. In addition, experimental evidence for and against a role of
mycobacterial infection is summarized, including recent attempts to detect
mycobacterial DNA in clinical samples from patients with sarcoidosis by
polymerase chain reaction.
PMID- 9764952
TI - Metals that cause sarcoidosis.
AB - Inhalation of metal dust or fume can cause granulomatous lung disease that mimics
sarcoidosis. Particular metals that possess antigenic properties which promote
granuloma formation include aluminum, barium, beryllium, cobalt, copper, gold,
rare earths (lanthanides), titanium, and zirconium. The occupational and
environmental exposure history holds the key to linking such metals with
seemingly idiopathic disease. We propose clinicians use a systematic approach to
investigating the occupational and environmental history and immunologic
responses of patients with sarcoidosis, in order to discriminate metal-induced
granulomatosis from sarcoidosis.
PMID- 9764953
TI - Animal models of granulomatous inflammation.
AB - The pathogenesis of granulomatous inflammation is often characterized as an
intense inflammatory response with accompanying fibroproliferation and deposition
of extracellular matrix. Many of these chronic disorders share a number of common
characteristics, including an enigmatic cause, unknown mechanisms of initiation
and maintenance, and often untreatable end-stage fibrosis. Granulomatous
inflammation can occur in a variety of diseases, such as tuberculosis,
sarcoidosis, berylliosis, and Wegner's granulomatosis. Unfortunately, these
diseases are often associated with substantial morbidity and mortality, as
therapeutic options may not be entirely efficacious. The lack of a clear
treatment strategy may underscore the limited scientific understanding of these
disorders. Thus, experimental models of granulomatous inflammation, which mimic
some of the specific characteristics of these responses, will be useful in
delineating the mechanisms of granuloma development. In addition, these models
may aid in the design of useful therapies for the treatment of these inflammatory
diseases.
PMID- 9764954
TI - Extrapulmonary sarcoidosis.
AB - The clinical manifestations of sarcoidosis are extremely heterogeneous and
overlap with a wide gamut of infectious and noninfectious granulomatous
disorders. Prognosis of sarcoidosis is highly variable. Spontaneous remissions
occur in nearly two thirds of patients, but chronic, progressive disease may
result in severe sequelae. Fatalities occur in 1% to 4% of patients. Pulmonary
manifestations typically dominate, but any organ can be affected. Skin, eye, and
peripheral lymph nodes are each involved in 20% to 30% of patients. Clinically
significant involvement of spleen, liver, bone, heart, kidney, or central nervous
system occurs in 2% to 6% of patients. Asymptomatic involvement of these organs
is far more common. We review the salient extrapulmonary features of sarcoidosis,
and compare and contrast specific features that may mimic other etiologies.
PMID- 9764955
TI - Sarcoidosis: is therapy effective?
AB - Treatment of sarcoidosis is controversial. The clinical expression and natural
history of sarcoidosis is variable, and spontaneous remissions occur in up to 60%
of patients. The decision to treat (or withhold treatment) is often difficult.
Corticosteroids, immunosuppressive/cytotoxic, and immunomodulatory agents are
used to treat chronic or progressive sarcoidosis, but prospective, randomized
trials assessing efficacy of these agents are lacking. Toxicities associated with
therapy may be substantial, particularly when high dosages are used. We review
the pharmacologic agents used to treat sarcoidosis, toxicities associated with
treatment, and appropriate use and monitoring of these therapeutic modalities.
PMID- 9764956
TI - Radiographic findings in semi-invasive pulmonary aspergillosis.
PMID- 9764957
TI - Therapeutic drug monitoring--antiepileptic drugs.
AB - AIMS: To provide a brief critical review of the basis and contemporary practice
of monitoring the concentrations of antiepileptic drugs in biological fluids.
METHODS: The review is based on literature data and observations from clinical
practice. RESULTS: As experience has accumulated, monitoring of antiepileptic
drug concentrations has come to be applied mainly to certain of the drugs when
present in whole plasma. For these drugs there is a reasonably established
relationship between drug concentrations and biological effects, but attention
still needs to be paid to issues such as the timing of the measurements in
relation to drug intake, the presence or absence of steady-state conditions, the
presence in plasma of active metabolites and possible nonlinear pharmacokinetics
of particular agents e.g. phenytoin. CONCLUSIONS: Plasma antiepileptic drug
concentration monitoring is coming to be used in a more thoughtful and critical
manner. Lack of adequate knowledge of matters such as the relationship between
the plasma concentrations and antiepileptic and toxic effects of the drugs, not
only the newer, but also the longer established ones, in particular clinical
situations, remains more important than deficiencies in analytical methodology in
limiting the clinical usefulness of antiepileptic drug concentration monitoring.
PMID- 9764958
TI - Prescription-event monitoring--recent progress and future horizons.
PMID- 9764959
TI - Midazolam pharmacokinetics following intravenous and buccal administration.
AB - AIMS: Midazolam has good anxiolytic qualities and is a well established
premedication agent before anaesthesia or short surgical procedures. The
objective of the present study was to determine pharmacokinetic data from
individual plasma concentration profiles obtained following intravenous and
buccal administration of midazolam. METHODS: Eight young healthy volunteers
received single doses of 5 mg midazolam i.v. and after a period of 1 week
buccally in a cross over manner. Blood samples were obtained up to 480 min. The
measurement of plasma midazolam concentrations was by gas-chromatography.
RESULTS: The maximum plasma concentration was 55.9 ng ml(-1) (range 35.6-77.9 ng
ml(-1)) at 30 min (range 15-90 min) following buccal administration. AUC was
calculated to be 15016 ng ml(-1) min (s.d. 3778 ng ml(-1) min) following i.v. and
11191 ng ml(-1) min (s.d. 1777 ng ml(-1) min) following buccal midazolam. This
gave a mean midazolam bioavailability of 74.5%. CONCLUSIONS: The pharmacokinetic
data presented in this study demonstrate a high bioavailability and reliable
plasma concentrations following buccal midazolam. The clinical benefit of buccal
midazolam may be in particular patient controlled premedication or sedation in
adults.
PMID- 9764960
TI - The gastrointestinal passage and release of beclomethasone dipropionate from oral
delivery systems in ileostomy volunteers.
AB - AIMS: To study the delivery of 15 mg beclomethasone 17,21-dipropionate (BDP) to
the distal part of the small bowel for three oral sustained-release formulations
(I-III) and a reference capsule in volunteer ileostomists, and to compare these
findings with the in vitro dissolution profiles. METHODS: Two groups of nine
ileostomy volunteers (aged 20-61 years), who were otherwise healthy, were
enrolled in the study. The recovery of BDP and its metabolite beclomethasone 17
monopropionate (B17P) in ileostomy effluent was investigated in a cross-over
study after administration of formulations I or II or a reference capsule
containing micronised BDP, and in a second open study after administration of
formulation III. Radio-opaque granules were coadministered for evaluation of
gastrointestinal passage. Ileostomy effluents were collected hourly for 10-12 h
following drug intake. After marker beads had been counted on X-rays, ileostomy
collections were analysed for BDP and its metabolites. Cumulative recovery, lag
time and mean transit time were determined for drug and marker beads. RESULTS:
Gastrointestinal passage characteristics were similar for all treatments. Total
drug recovery was approximately three times higher for the sustained-release
formulations than for the reference capsule. Recovery of B17P from stoma fluid
samples was significantly lower for formulation III than for formulations I and
II. CONCLUSIONS: The novel oral formulations delivered substantial amounts of
steroid drug at the distal small bowel/proximal colon, which may warrant further
studies to evaluate clinical applicability.
PMID- 9764961
TI - Chloroquine modulation of specific metabolizing enzymes activities: investigation
with selective five drug cocktail.
AB - AIMS: The aim of this study was to investigate whether chloroquine can inhibit
drug metabolism in humans, if such inhibition is general or selective for certain
enzymes and evaluate the potential for and clinical significance of any drug-drug
interactions when chloroquine is co-administered with other drugs. METHODS: The
study was conducted in fourteen normal non-smoking healthy male volunteers using
a cocktail of five drugs consisting of caffeine, mephenytoin, debrisoquine,
chlorzoxazone and dapsone to assess activities of cytochromes P450 (CYP) 1A2,
2C19, 2D6, 2E1 and 3A4 respectively. Dapsone was also used to assess N
acetyltransferase activity. The activities were assessed at baseline, after one
and seven daily doses (250 mg daily) of chloroquine and 7 and 14 days after
stopping chloroquine dosing. RESULTS: Chloroquine caused a progressive and
significant decrease in CYP2D6 activity as measured by debrisoquine metabolism
from first to seventh dose and the activity returned to baseline gradually over
14 days after stopping administration. There was no effect on the metabolism of
any of the other probe drugs. CONCLUSIONS: Chloroquine has been shown to be
capable of inhibiting the activity of CYP2D6 in vivo in humans. This effect is
selective as activities of other enzymes investigated were not affected. The
effect was modest but suggests a potential for drug-drug interactions when co
administered with other drugs that are substrates for this enzyme. The clinical
significance of such an interaction will depend on the therapeutic index of any
drug involved.
PMID- 9764963
TI - Population pharmacokinetics of gentamicin in patients with cancer.
AB - AIMS: The purpose of this study was to describe the population pharmacokinetics
of gentamicin in patients with cancer, to identify possible relationships between
clinical covariates and population pharmacokinetic parameter estimates and to
examine the relevance of existing dosage nomograms in light of the population
model developed in these patients. METHODS: Data were collected prospectively
from 210 patients with cancer and were analysed with package NONMEM. Data were
split into two sets: a population data set and an evaluation set. Creatinine
clearance was estimated using measured creatinine concentrations and using 'low'
creatinines set to a minimum of 60 micromol l(-1), 70 micromol l(-1) or 88.4
micromol l(-1) RESULTS: A two compartment model was fitted to the concentration
time curve. Two best models were obtained, one that related clearance to
estimated creatinine clearance (minimum creatinine value 60 micromol l(-1)) and
the other that related clearance to age, creatinine concentration and body
surface area. Volume of the central compartment was influenced by body surface
area and albumin concentration. For both models 90% of measured concentrations
lay within the 95% confidence interval of the simulated concentrations and the
mean prediction errors were -7.2% and -6.6%, respectively. A final analysis
performed in all patients identified the following relationship CL (1 h(-1))=0.88
x (1 + 0.043 x creatinine clearance) and central volume of distribution V1
(1)=8.59 x body surface area x (albumin/34)(-0.39). The mean population estimate
of intercompartmental clearance (Q) was 1.301 h(-1) and peripheral volume of
distribution (V2) was 9.801. Coefficient of variation was 18.5% on clearance and
28.2% on Q. Residual error expressed as a standard deviation was 0.36 mg l(-1) at
1.0 mg l(-1) and 1.32 mg l(-1) at 8.0 mg l(-1). The mean population estimate of
clearance was 4.21 h(-1) and volume of distribution (Vss) was 24.61 (0.381 kg(
1)). The mean population estimates of half-lives were 1.8 h and 8.0 h.
CONCLUSIONS: In the context of published nomograms this analysis indicated that
both the traditional approach and the new, 'once daily' approach should achieve
satisfactory concentrations in cancer patients although serum concentration
monitoring is required to confirm optimal dosing in individual patients.
PMID- 9764962
TI - Caffeine based measures of CYP1A2 activity correlate with oral clearance of
tacrine in patients with Alzheimer's disease.
AB - AIMS: To study the potential utility of caffeine based probes of CYP1A2 enzyme
activity in predicting the pharmokinetics of tacrine in patients with Alzheimer's
disease. METHODS: The pharmokinetics of a single 40 mg oral dose of tacrine were
measured in 19 patients with Alzheimer's disease. Each patient also received 2 mg
kg(-1) [13C-3-methyl] caffeine orally and had breath and urine samples collected.
RESULTS: Tacrine oral clearance (CL F(-1) kg(-1)), which varied 15-fold among the
patients, correlated significantly with the 2 h total production of 13CO2 in
breath (r=0.56, P=0.01), and with each of two commonly used urinary caffeine
metabolite ratios: the 'paraxanthine/caffeine ratio' (1,7X + 1, 7U)/1,3,7X)
(r=0.76, P=0.0002) and the 'caffeine metabolic ratio' (AFMU + 1X + 1U)/1,
7U)(r=0.76, P=0.0001). CONCLUSIONS: These observations support a central role for
CYP1A2 in the in vivo disposition of tacrine and the potential for drug
interactions when tacrine treated patients receive known inducers or inhibitors
of this enzyme. The magnitude of the correlations we observed, however, are
probably not sufficient to be clinically useful in individualizing tacrine
therapy.
PMID- 9764964
TI - Paracetamol plasma and cerebrospinal fluid pharmacokinetics in children.
AB - AIMS: Paracetamol has a central action for both antipyresis and analgesia.
Maximum temperature decrease and peak analgesia are reported at 1-2 h after peak
plasma paracetamol concentration. We wished to determine the relationship between
plasma and cerebrospinal fluid (CSF) pharmacokinetics in children. METHODS:
Concentration-time profiles in plasma and CSF after nasogastric paracetamol 40 mg
kg(-1) were measured in nine children who had indwelling ventricular drains.
Estimation of population pharmacokinetic parameters was made using both a
standard two-stage population approach (MKMODEL) and a nonlinear mixed effect
model (NONMEM). Results were standardized to a 70 kg person using an allometric
power model. RESULTS: Both approaches gave similar estimates. NONMEM parameter
estimates were clearance 10.21 h(-1) (CV 47%), volume of distribution 67.11 (CV
58%) and absorption rate constant 0.77 h(-1) (CV 49%). Cerebrospinal fluid
concentrations lagged behind those of plasma. The equilibration half time was
0.72 h (CV 117%). The CSF/plasma partition coefficient was 1.18 (CV 8%).
CONCLUSIONS: Higher concentrations in the CSF probably reflect the lower free
water volume of plasma. The CSF equilibration half time suggests that CSF
kinetics approximate more closely to the effect compartment than plasma, but
further time is required for paracetamol to exert its effects. Effect site
concentrations equilibrate slowly with plasma. Paracetamol should be given 1-2 h
before anticipated pain or fever in children.
PMID- 9764965
TI - A comparison of the cardiovascular effects of levobupivacaine and rac-bupivacaine
following intravenous administration to healthy volunteers.
AB - AIMS: The aim of this study was to compare the cardiovascular effects of
levobupivacaine with those of rac-bupivacaine following i.v. administration to 14
healthy male volunteers. METHODS: Drugs were infused (at 10 mg min(-1)) using a
randomized, double-blind, complete crossover procedure with a washout period of
at least 1 week. The administration of drug was discontinued on the appearance of
defined CNS symptoms or when a total of 150 mg had been given. Parameters
measured were arterial blood pressure, heart rate, ECG, ejection fraction,
acceleration index, stroke index and cardiac index. RESULTS: The mean doses
administered were 56.1 mg and 47.9 mg for levobupivacaine and rac-bupivacaine
respectively and the maximum mean plasma concentrations were 2.62 and 2.25 microg
ml(-1) respectively. Despite the dose and plasma concentrations being comparable,
levobupivacaine produced a statistically significant smaller reduction in mean
stroke index (-5.14 vs -11.86 ml m(-2), P=0.001), acceleration index (-0.09 vs
0.20 s(-2), P=0.011) and the ejection fraction (-2.50 vs -4.29%, P=0.024). Both
levobupivacaine (non significant) and rac-bupivacaine (significant) produced
small increases in the PR interval and the corrected QT interval and although the
effects of rac-bupivacaine appeared to be greater the difference between the two
drugs was not significant. CONCLUSIONS: In conclusion, this study has shown that
following i.v. administration levobupivacaine produces significantly less effects
on cardiovascular function than does rac-bupivacaine. In particular the negative
inotropic effect for levobupivacaine was less than that for rac-bupivacaine as
indicated by changes in stroke index, acceleration index and ejection fraction.
PMID- 9764966
TI - Terfenadine and risk of acute liver disease.
AB - AIMS: To estimate the risk of idiopathic acute liver disease among users of
terfenadine. METHODS: We conducted a population-based cohort study based on the
General Practice Research Database (GPRD) in the U.K. All persons who received at
least one prescription for terfenadine during the period 1991 through 1995 were
eligible for the study. Among these patients we identified all those with a
diagnosis of a liver disorder requiring hospitalization or referral to a
consultant within 60 days of a prior prescription for terfenadine. We obtained
clinical records, including hospital discharge summaries, consultant reports and
relevant laboratory results in order to identify a potentially drug-inducible
liver illness. RESULTS: From a cohort of 210683 recipients of terfenadine, we
found only three cases of acute liver disease where a causal connection to
terfenadine could not be ruled out, yielding a risk estimate of 1.4/100000 users
(95% CI 0.5, 4.2) and 0.5/100000 prescriptions (95% CI 0.2, 1.4). All cases were
receiving a concomitant hepatotoxic drug and all had a full recovery. CONCLUSION:
The use of terfenadine is rarely associated with idiopathic acute liver disease.
PMID- 9764967
TI - Constipation as an adverse effect of drug use in nursing home patients: an
overestimated risk.
AB - AIMS: To investigate whether results from case control and cross sectional
studies which suggest an association between laxative use and other drug use
could be confirmed in a cohort study of nursing home patients. METHODS: A
prospective cohort study of 2355 nursing home patients aged 65 years and over was
performed to estimate the incidence relative risk of constipation associated with
drug use. The study was conducted with prescription sequence analysis of each
resident's detailed pharmacy records and data on morbidity and mobility. RESULTS:
Use of drugs, which according to the summaries of product characteristics (SPC)
and the literature on adverse drug effects have moderately to strongly
constipating properties, was associated with a relative risk of 1.59 (95% CI 1.24
2.04) for the occurrence of constipation during exposure time. Use of drugs with
mildly to moderately constipating effects was not associated with laxative use
(RR 1.13; 95% CI 0.93-1.38). Stratification on the level of age, gender, type of
nursing (psychogeriatric or somatic), morbidity, number of medications taken and
mobility showed no confounding effects of these variables on outcome
measurements. These variables all acted as effect modifiers. Effect of age and
number of medications taken on the relative risk was nonlinear. CONCLUSIONS:
Although an association between drugs that exhibit moderately to strongly
constipating effects and occurrence of constipation was found, the risk was not
as high as seen in previous studies. The high prevalence of constipation in
nursing home patients is only partly due to adverse drug effects.
PMID- 9764968
TI - Nitric oxide: an important role in the maintenance of systemic and pulmonary
vascular tone in man.
AB - AIMS: The aim of this study was to examine whether nitric oxide (NO) has an
important role in maintaining basal vascular tone in normal man by examining the
effects of nitric oxide inhibition using N(G)-monomethyl-L-arginine (L-NMMA) on
systemic and pulmonary haemodynamics. METHODS: Ten normal male volunteers 26 +/-
1.6 years were studied on two separate occasions in a double-blind, placebo
controlled crossover study. They were randomised to receive either a continuous
infusion of L-NMMA (4 mg kg(-1) h(-1)) with a front loaded bolus (4 mg kg(-1)) or
volume matched placebo. Pulsed wave Doppler echocardiography was used to measure
cardiac output (CO), mean pulmonary artery pressure (MPAP) and hence systemic
vascular resistance (SVR) and total pulmonary vascular resistance (TPR).
Measurements were made prior to infusion (t0) and after 4, 8, and 12 min (t1, t2
and t3). RESULTS: Infusion of L-NMMA significantly increased mean arterial blood
pressure (MAP), SVR and TPR and significantly reduced heart rate (HR), stroke
volume (SV) and CO compared to placebo. These effects were observed at t1 and
persisted during the entire infusion period. CONCLUSIONS: These results are
consistent with a role for basal nitric oxide generation in the maintenance of
basal systemic and pulmonary vascular tone in normal man.
PMID- 9764969
TI - Effect of age and gender on the pharmacokinetics of eprosartan.
AB - AIMS: To compare the pharmacokinetics of eprosartan between young (18-45 years)
and elderly (65 years) men and between young men and young, premenopausal women
(18-45 years). METHODS: Twenty-four subjects (eight subjects/group) received a
single 200 mg eprosartan oral dose followed by serial blood sampling over 24 h.
RESULTS: Eprosartan was safe and well tolerated. There were no apparent
differences in the pharmacokinetics of eprosartan between young females and young
males or in the plasma protein binding of eprosartan (98%) for the three groups.
On average, AUC (0,infinity) and Cmax values were approximately 2-fold higher in
elderly men than young men [AUC (0,infinity) 95% CI: 1.22, 4.34; Cmax 95% CI:
0.98, 4.001. Similarly, unbound AUC (0,infinity) and Cmax values were, on
average, approximately 2-fold higher in elderly men than young men [unbound AUC
(0,infinity) 95% CI: 1.29, 4.44; unbound Cmax 95% CI: 1.02, 4.12]. tmax was
delayed in the elderly men compared with young men, with a median difference of
2.5 h (95% CI: 1.00, 3.01 h). CONCLUSIONS: No gender differences were observed in
the pharmacokinetics of eprosartan. There were approximately two fold higher AUC
and Cmax values for eprosartan observed in elderly men as compared with young
men, most likely due to increased bioavailability of eprosartan in the elderly.
Based on the excellent safety profile in the elderly in Phase III clinical trials
(doses up to 1200 mg eprosartan) eprosartan can be safely administered to elderly
hypertensive patients without an initial dose adjustment. Subsequently, the dose
of eprosartan, as for other antihypertensive agents, may be individualized based
on tolerability/response.
PMID- 9764970
TI - Evidence for a pharmacokinetic interaction between itraconazole and tacrolimus in
organ transplant patients.
PMID- 9764971
TI - Norfloxacin exhibits negligible serum concentrations after repeated conjunctival
instillation in children.
PMID- 9764972
TI - Lineage and development of the parasympathetic nervous system of the embryonic
chick heart.
AB - We were interested in the contribution of the cardiac neural crest to the
complete anterior and posterior nerve plexus of the chick heart. This includes
the pathways by which these cardiac neural crest-derived neuronal precursors
enter the heart. As lineage techniques we used the traditional quail-chick
chimera in combination with the newly introduced technique of retroviral reporter
gene transfer to premigratory cardiac neural crest cells. Retrovirally infected
embryos (n=23) and quail-chick chimeras (n=19) between stages HH27 and 40, were
immunohistochemically evaluated, using the lineage markers LacZ (retroviral
reporter) and QCPN (anti-quail nuclear marker), respectively and the neuronal
differentiation markers HNK-1, RMO-270 and DO-170. Between stages HH27 and 33,
quail-derived and LacZ positive cells were situated around the arterial cardiac
vagal branches at the arterial pole, and vagal branches along the anterior
cardinal veins and the sinal vagal branch at the venous pole. From stage HH35
onward, QCPN/LacZ-positive cardiac ganglia were observed throughout the anterior
and posterior plexus and were mainly concentrated in the subepicardium near the
distal ends of the arterial cardiac vagal branches and the sinal cardiac vagal
branch respectively. From stage HH36 both the anterior and posterior plexus
contained a population of large cardiac ganglion cells and a population of
smaller cells along nerve branches as well as in the cardiac ganglia, which means
that differentiation starts in both plexus at the same time. Furthermore only
nerve fiber connections between the anterior and posterior plexus were observed.
These results show that the cardiac neural crest contributes to the cardiac
ganglion cells from both the entire anterior and posterior plexus. Furthermore
these results suggest that these precursor cells enter the arterial pole via the
arterial cardiac vagal branches and the venous pole via the sinal cardiac vagal
branch without intermixing. Finally we show that in addition to the cardiac
ganglia, the cardiac neural crest contributes to small myocardial glia or
undifferentiated cells along nerve fibers, and some myocardial nerve fibers as
well as nerve tissue in the adventitia of the large veins at the venous pole and
in the adventitia of the coronary arteries.
PMID- 9764973
TI - Differences in axial curvature correlate with species-specific rate of neural
tube closure in embryos of chick, rabbit, mouse, rat and human.
AB - Studies on the mouse strain curly tail, a mutant for neural tube defects, have
indicated that axial curvature is an important factor in neural tube closure.
Previously reported results from experimental interventions in both mouse and
chick embryos indicated that curvature along the craniocaudal axis and closure of
the posterior neuropore (PNP) are inversely related, a correlation that is also
proposed for the rabbit embryo. It was hypothesized that this relationship is a
sign of a more general mechanism. Therefore, in the present report the number of
species in which axial curvature is described along the craniocaudal axis was
extended to include the rat and human. Next, the closure rate of the neural tube
as well as the curvature of the PNP region was determined morphometrically for
embryos of the following species: chick, rabbit, mouse, rat and human. Although
the relationship between neural tube closure and axial curvature appeared
specific for each species in the comparative analysis, a general association of
increased rate of closure with a decreased curvature emerged. It is concluded
that axial curvature is an important factor in neurulation.
PMID- 9764974
TI - Septotemporal distribution of [3H]MK-801, [3H]AMPA and [3H]Kainate binding sites
in the rat hippocampus.
AB - The distribution of glutamate receptors in transverse hippocampal sections has
been well investigated. However, in spite of the known septotemporal gradients of
hippocampal connectivity no systematic studies exist about the distribution of
glutamate receptors along the septotemporal (longitudinal) hippocampal axis.
Therefore, in the present study this issue was investigated using receptor
autoradiography for the [3H]MK-801, [3H]AMPA and [3H]Kainate binding sites.
Hippocampi from 30-day-old rats were sectioned perpendicularly to their
longitudinal axis, yielding a total of 25-30 equidistantly spaced autoradiographs
for each hippocampus. For each section layer-specific concentrations of binding
sites were calculated by the aid of a computerized image analysing system. The
dependency of concentrations of binding sites on the septotemporal position was
evaluated by regression analysis. Gradients of binding were confined to distinct
hippocampal layers. Significant septotemporal gradients of [3H]MK-801 binding
were observed in selected layers of CA1 and the dentate gyrus, a septal to
temporal decrease of binding in the oriens and radiatum layers of CA1 being most
prominent. For [3H]AMPA, significant septotemporal gradients of binding were
restricted to layers of CA3, CA4 and the dentate gyrus, with values generally
increasing from septal to temporal levels. The observed septotemporal gradients
possibly reflect functional segregations along the longitudinal hippocampal axis
and could be important for the comparability of ligand binding studies using
transverse hippocampal sections or hippocampal slice cultures.
PMID- 9764975
TI - Restricted distribution of S-phase cells in the anterior subventricular zone of
the postnatal mouse forebrain.
AB - The anterior subventricular zone (SVZa) is the site for postnatal neurogenesis of
interneurons of the olfactory bulb (OB). Concurrently or after proliferation,
neuronal precursors therein migrate within it to reach the OB, an event known as
the rostral migratory stream (RMS). We used bromodeoxyuridine (BrdU)
incorporation with short survival times to investigate the distribution of S
phase nuclei in the SVZa/RMS of the postnatal mouse. We observed that they were
distributed along a radial, outside-in, decreasing gradient that persisted until
postnatal day 10 (P10), then faded away to finally disappear by P16. After longer
post-injection survival times labeled cell distribution became homogeneous. GFAP
positive glia are present at the periphery but not at the core of the SVZa. Our
results represent the first evidence of a discrete spatial organization of a cell
cycle phase within the SVZ, and also suggests a segregation of proliferating and
migrating cells in the rostral migratory stream of the early postnatal mouse.
PMID- 9764976
TI - Distribution of glial fibrillary acidic protein and vimentin-immunopositive
elements in the developing chicken brain from hatch to adulthood.
AB - The present study describes the distribution of glial fibrillary acidic protein
(GFAP) and vimentin-immunopositive structures in the brain of the domestic
chicken (Gallus domesticus) from hatching to maturity. The telencephalon is
penetrated by a vimentin-immunopositive radial fibre system, representing a
modified form of radial glia, in day-old chicks. Numerous fibres of this system
persist until adulthood, mainly in the lobus parolfactorius, lamina medullaris
dorsalis and lamina frontalis superior. GFAP immunoreactivity also appears in the
course of development in these fibres. The distribution of GFAP-immunopositive
astrocytes in the post-hatch telencephalon is like that found in adult chicken,
except for the ectostriatum, in which an adult-like GFAP-immunostaining only
develops during week three. This delay may be associated with a relatively slow
maturation of this visual centre. In the diencephalon and in the mesencephalic
tegmentum of day-old chicks GFAP-immunopositive astrocytes are confined to the
border zone of several nuclei. In these areas as well as in the pons most GFAP
positive astrocytes only appear gradually during the first two post-hatch weeks,
although radial fibres occur only sparsely at hatch. Summarizing these results, a
gradual replacement of radial fibres by astrocytes, typical of mammals, cannot be
found in chicken. In the nucleus laminaris we observed a characteristic palisade
of non-ependymal glia, reactive to GFAP but not to vimentin, which almost
completely disappears by adulthood. We suggest that this glial system is
instrumental in the development of the dendritic organisation of this nucleus.
The optic tectum displays a dense array of GFAP-immunopositive radial glia at
hatching, similar in this to the situation found in reptiles. However, in the
tectum of reptiles this radial glia persists for the lifetime, whereas in the
chick it disappears from the superficial tectal layers. This phenomenon may
reflect the fact that there is no replacement of tectal cells or regeneration of
retinotectal pathways in the chicken. In the early stage, the large cerebral
tracts were found to contain dense accumulations of GFAP-positive cells, with
peculiarly long outgrowths accompanying nerve fibres. No vimentin
immunopositivity was found in these glial elements; however vimentin was present
in the glia situated at the optic chiasm, the anterior commissure and at other
decussations. These structures, as well as the raphe, displayed the most intense
vimentin-immunopositivity in the post-hatch chicken. This characteristic glial
population may represent glial elements that have been reported to regulate fibre
crossing at the midline.
PMID- 9764977
TI - Supraependymal cells and fibers during the early stages of chick rhombencephalic
development.
AB - Supraependymal cellular elements are a constant feature in the adult
cerebroventricular system. However, there has been no analysis of their
distribution and morphology during the embryonic stages of the chick brain. The
ultrastructural features of the rhombencephalic luminal surface of chick embryos
ranging from stage 10 to 22 were studied with both scanning and transmission
electron microscopy. In addition, immunocytochemistry and confocal laser
microscopy were used to examine the presence of 68 kD neurofilaments in
supraependymal elements. The ultrastructural observations revealed significant
morphological differences in the apical cell surface between the cells at
rhombomere boundaries and those in the rhombomere bodies. These differences
support the idea that the boundary and the body of rhombomeres contain two
morphologically distinct cell types. Supraependymal (SE) cells and SE fibers were
present in the rhombencephalon of all embryos studied from stage 12 to 22. The
cells were bipolar spindle-shaped. The SE fibers showed a characteristic spatial
pattern within the rhombencephalon, following a straight course parallel to the
rhombomere boundaries. The SE fibers showed varicosities and their endings
contained small vesicles. Both SE cells and SE fibers were positive for 68 kD
neurofilaments. Their morphology and reactivity for neurofilaments indicate a
neuronal function. The constant presence of SE cells and SE fibers on the surface
of the developing rhombencephalon, their special pattern and close relationship
with the neural tube fluid (NTF) suggest that these supraependymal elements may
be involved in a neuronal signalling pathway between different parts of the same
rhombomere and also in chemical communication and integration within the
ventricular system, linking distant parts of the developing central nervous
system by means of NTF.
PMID- 9764978
TI - Effects of tri-iodothyronine (T3), insulin, insulin-like growth factor I (IGF-I)
and transforming growth factor beta1 (TGFbeta1) on the proportion of insulin
cells in cultured embryonic chick pancreas.
AB - With a view to ultimately identifying factors involved in the development of
pancreatic insulin cells, we have cultured dorsal pancreatic buds from 5-day
chick embryos on a basement membrane matrix (Matrigel) in a serum-free medium
supplemented with selected factors. The endodermal components of the buds were
freed of almost all the mesenchyme so as to eradicate as much as possible of this
source of some such factors. In 7-day cultures, insulin and glucagon cells were
demonstrated immunocytochemically; numbers of insulin cells were expressed as a
percentage of insulin plus glucagon cell counts. Our standard medium contained
insulin. Addition of tri-iodothyronine to this medium did not increase the
proportion of insulin cells, but in combination with raised concentrations of
glucose and essential amino acids it improved somewhat the marked increase
previously recorded for these nutrient conditions. Omission of insulin from the
standard medium greatly reduced the proportion of these cells; substitution of
insulin by insulin-like growth factor I increased the proportion considerably
more than did insulin. To test for an overall effect of growth factors, explants
were cultured in standard medium on Matrigel containing reduced amounts of growth
factors: the proportion of insulin cells proved to be increased over that reached
on normal Matrigel. The suspicion that transforming growth factor beta1, a
component of Matrigel, might act to reduce the proportion of insulin cells was
tested and found to be correct. It is suggested that the different factors
studied here may affect either or both of proliferation and determination in the
differentiation pathway of insulin vis-a-vis glucagon cells.
PMID- 9764980
TI - The "interferon sensitivity determining region" of hepatitis C virus is a stable
sequence element.
AB - BACKGROUND/AIMS: A sequence of 40 amino acids within the nonstructural protein 5A
of hepatitis C virus (HCV) has been suggested to be an interferon sensitivity
determining region (ISDR). The variations in the ISDR after 12-14 years of
chronic infection and the correlation between ISDR and interferon response were
studied in patients who were infected by the same HCV isolate. METHODS: We
determined the HCV-ISDRs of 13 chronically infected patients by direct sequencing
of polymerase chain reaction products. All patients were infected by isolate HCV
AD78, but differed with respect to their sensitivity to interferon. Four patients
were complete responders, two patients were non-responders, and seven showed a
partial response. RESULTS: The ISDR of HCV-AD78 differed from a prototypical HCV
1b sequence in one amino acid and was therefore classified as an intermediate
type. Direct sequencing of the HCV-ISDRs of the patients 12-14 years after
infection, but before interferon therapy, revealed a rate of 2.2x10(-3)
nucleotide substitutions per site per year, resulting in only single intermediate
type amino acid exchanges. All sequences ranked with the intermediate type.
Moreover, during interferon treatment no selection to a wild type ISDR was
observed in five partial responders. CONCLUSIONS: Within the homogeneous patient
group examined here, no correlation was found between the ISDR and the interferon
response. Recent studies found only a small number of mutant type ISDRs in
Europe. Additionally, our results indicate that the ISDR is a stable sequence
element. This provides an explanation for the divergent data relating to the
importance of the ISDR in different geographical regions.
PMID- 9764979
TI - Core variability does not affect response to interferon alpha in HBeAg negative
chronic hepatitis B.
AB - BACKGROUND/AIMS: The pre-core stop codon variant (A 1896) of hepatitis B virus
(HBV) has been associated with chronic active liver disease with acute
exacerbations and a high relapse rate after an initial response to alpha
interferon (IFN-alpha) therapy. Poor sustained response has been correlated with
a high prevalence of mutations in the core region, potentially enabling escape
from the immune system. The aim of this study was to analyse the predictive
factors of response to IFN-alpha in such patients. METHODS: We studied the
baseline clinical, biochemical, histological, serological and virological
parameters in 30 hepatitis B s antigen positive (HBsAg-positive)/hepatitis B e
antigen negative (HBeAg-negative) Greek patients with chronic liver disease. The
patients were selected from a cohort who received IFN-alpha for 24 weeks. These
were divided into three groups of ten sequential patients: those with no response
to IFN-alpha treatment, those who relapsed after an initial response, and those
with a sustained response. Serum HBV DNA was measured by a liquid hybridisation
method, and the anti-HBc IgM was quantitated by the IMx analyser. The amino-acid
sequence of core protein residues 40-89, a region where a clustering of mutations
has been detected previously in severe hepatitis, was compared with a sequence
from an HBeAg positive patient with chronic liver disease. RESULTS: Multiple
logistic regression analysis showed that the initial response to IFN-alpha could
be predicted by pre-treatment absence of HBcAg staining in the liver and high ALT
values, but no parameter could predict sustained response. The pre-treatment
extent and pattern of aminoacid substitutions in the core region sequenced was
similar in all groups studied and was not associated with IFN-alpha response.
CONCLUSIONS: In HBsAg-positive/HBeAg-negative patients with chronic liver
disease, response to IFN-alpha therapy was not correlated with genomic
variability of the core region. Other parameters such as pre-treatment HBcAg
positivity in the liver and alanine aminotransferase values indicative of disease
activity before treatment were associated with initial IFN-alpha response.
PMID- 9764981
TI - Is there an optimal time to measure quantitative HCV RNA to predict non-response
following interferon treatment for chronic HCV infection?
AB - BACKGROUND/AIMS: Current criteria to predict sustained response for a patient
with chronic hepatitis C virus during interferon treatment are not consistent.
The aim of this study was to determine a reliable point in time to predict non
response to therapy, as a theoretical basis for early cessation of treatment.
METHODS: Sera (-70 degrees C) from 66 patients treated with interferon (3 million
units three times a week for 6 months) were assayed with a quantitative
polymerase chain reaction (sensitivity < or =100 copies per milliliter).
Evaluations were made at baseline, during treatment at weeks 1, 2, 4, 12, and 24,
and at follow-up week 48. Biochemical response was defined using standard alanine
aminotransferase criteria. Virologic response was defined as: sustained if loss
of HCV RNA persisted through therapy and follow-up; relapse if HCV RNA became
undetectable but reappeared during treatment or follow-up; and non-response if
HCV RNA remained detectable during the study period. Alanine aminotransferase and
HCV RNA results were analyzed at defined time intervals to determine a predictive
value for non-response and sustained response. RESULTS: HCV RNA results are a
more accurate predictor than alanine aminotransferase for both non-response and
sustained response. Serum HCV RNA predicted non-response better than sustained
response. The optimal time to predict non-response with serum HCV RNA was
treatment week 12. CONCLUSIONS: Treatment week 12 results indicate that HCV RNA
was a more accurate predictor for non-response than serum alanine
aminotransferase. This prediction would have theoretically permitted stopping
treatment for 75% of the patients in this study at treatment week 12 allowing an
overall cost savings of 28%.
PMID- 9764982
TI - Treatment of chronic hepatitis C with alpha-interferon plus ofloxacin in patients
not responding to alpha-interferon alone.
AB - BACKGROUND/AIMS: Ofloxacin, a quinolone antibiotic, was recently shown to
increase the primary response rate to alpha-interferon treatment of chronic
hepatitis C. METHODS: Fifty-five patients with chronic hepatitis C were scheduled
to receive 3 MU of a-interferon, three times a week, for 1 year. After 3 months
of therapy, patients who were still HCV RNA-positive in serum started receiving a
combined regimen with 3 MU of alpha-interferon, three times a week, plus
ofloxacin, 600 mg daily, per os. After 3 months of combined therapy, patients
with undetectable serum HCV RNA continued the combined regimen for another 6
months, whereas patients who were still HCV RNA-positive were definitively
considered as non-responders and withdrawn from the study. Serum HCV RNA levels
were quantitatively evaluated after 3 months of therapy with a-interferon alone
and compared with those detected after 3 months of combined regimen. RESULTS:
Among the 54 patients who completed the first 3 months of treatment, 32 (59.3%)
still had HCV RNA detectable in serum and started receiving the ofloxacin/alpha
interferon therapy. Among the 26 patients who completed the 3 additional months
of combined regimen, only one showed a virological response: this patient
maintained a complete response to the end of combined treatment, but relapsed
thereafter. The combination therapy had no effect on the serum HCV RNA or alanine
aminotransferase levels. CONCLUSIONS: The combined administration of alpha
interferon and ofloxacin to patients with chronic hepatitis C who have not
responded to alpha-interferon alone does not increase the primary virological
response rate.
PMID- 9764983
TI - A clinical and virological study of hepatitis C virus-related cryoglobulinemia in
Germany.
AB - BACKGROUND/AIMS: Several reports, especially from Southern Europe, have
demonstrated a close association between hepatitis C virus (HCV) infection and
mixed cryoglobulinemia. In this study we have analyzed the significance of HCV
related cryoglobulinemia in Germany. METHODS: Sera from 79 patients with
cryoglobulinemia of type I (n=21), II (n=28) or III (n=30) were investigated for
HCV markers. Furthermore, 132 consecutive patients with chronic hepatitis C were
studied for the presence of cryoglobulins. Genotypes of HCV were determined
according to Simmonds, and HCV-RNA concentrations were measured in patients with
and without cryoglobulinemia. RESULTS: In 79 patients with cryoglobulinemia we
found anti-HCV antibodies in 17 (22%) and HCV-RNA in 11 patients (14%). HCV
antibodies were more frequent in essential (44%) compared to secondary mixed
cryoglobulinemia (15%). In 132 patients with chronic HCV infection cryoglobulins
were detected in 37 patients (28%), in 21 of them at low levels. Clinical
symptoms due to cryoglobulinemia were observed in eight of the 37 patients,
severe vasculitis in three patients with high cryocrit-levels and
cryoprecipitation at room temperature. HCV genotype 1 and subtype 1b were most
prevalent, both in patients with and without cryoglobulinemia, and mean HCV-RNA
levels were not different between the two groups. Comparison of HCV-RNA levels in
cryoprecipitates, supernatant and native serum suggests binding of HCV-RNA to the
cryoprecipitate with different affinity in individual patients. CONCLUSIONS: The
lower prevalence of HCV-related cryoglobulinemia in our study compared with data
from Italy and France suggests a south-north gradient in the prevalence of HCV
associated cryoglobulinemia in Europe.
PMID- 9764984
TI - In vitro inhibition of the hepatitis delta virus replication mediated by
interferon and trans-ribozyme or antisense probes.
AB - BACKGROUND/AIMS: In this study, the inhibition of hepatitis delta virus
replication mediated by trans-ribozyme and antisense probes, alone or in
combination with recombinant interferon alpha-2a, has been assayed. METHODS: A 60
nucleotide-long designed trans-ribozyme, which contains the catalytic core of the
hammerhead ribozyme, and a 163-nucleotide-long antisense probe were directed
against the same region of the viral genome in in vitro and cell culture systems.
RESULTS: The ribozyme activity, assayed in a chemically isolated system, resulted
in the trans-cleavage of 10-20% of the 40-nucleotide-long RNA substrate. A 5
nucleotide deletion in one of the flanking arms, obtained by random mutagenesis,
resulted in enhancement of the trans-cleavage activity in as many as 40-60% of
the substrate molecules. The efficiency of the optimized trans-ribozyme and
antisense probes against the complete viral genome was assayed in a cell culture
system. The inhibitory efficacy (25%) of the trans-ribozyme is lower than that of
the antisense probe (35%) or interferon at 1000 U/ml (47%). An enhancement of the
interferon efficacy was achieved when it was administered in cells having a
previous basal expression of ribozyme (70%) or antisense probes (83%).
CONCLUSIONS: These results suggest that the combination of ribozyme or antisense
probes with interferon could be a promising approach to the treatment of RNA
virus infections.
PMID- 9764985
TI - Ecstasy: a common cause of severe acute hepatotoxicity.
AB - BACKGROUND/AIMS: Ecstasy is a synthetic amphetamine recently identified as a
possible cause of acute liver injury. This drug is consumed by young people and
has a marked effect on improving sociability. The extent of ecstasy-associated
severe hepatic damage is unknown to date. METHODS: The clinical histories of 62
patients with acute liver failure admitted to the Intensive Care Liver Unit
between January 1994 and December 1996 were reviewed to assess the frequency, the
epidemiological, clinical and histological characteristics and the outcome of
ecstasy-induced severe hepatitis. RESULTS: Over this period of time, five
patients (8%) were admitted because of ecstasy-induced acute liver failure,
representing 31% of the cases with drug hepatotoxicity. Ecstasy was the second
most common cause of liver injury in patients under the age of 25 years, being
20% in this subset of patients and 36% after ruling out the cases of viral
etiology. All the patients had severe liver disease of acute onset, with
jaundice, high peak of serum transaminases activity, hypoglycemia and low
prothrombin activity, but no hepatic encephalopathy. Full recovery was observed
in all cases from 3 to 12 months. CONCLUSIONS: Ecstasy is responsible for a
relatively high number of cases of acute liver failure in young people.
Therefore, the use of this drug should be investigated in all patients with
severe hepatitis of unclear origin. Efforts must be made to advise young people
of the risks of ecstasy consumption.
PMID- 9764986
TI - Contraction of human hepatic stellate cells activated in culture: a role for
voltage-operated calcium channels.
AB - BACKGROUND/AIMS: Voltage-operated calcium channels are essential for the
regulation of vascular tone and are potential targets for vasodilating agents.
They regulate calcium entry and thereby cell contraction in vascular cell types.
Hepatic stellate cells in the activated phenotype have contractile properties and
could participate in the regulation of sinusoidal blood flow. Thus, this study
was aimed at investigating the presence of voltage-operated calcium channels in
human hepatic stellate cells activated in culture and the effects of their
stimulation on intracellular calcium concentration ([Ca2+]i) and cell
contractility. METHODS: Binding studies using [3H]-nitrendipine were performed to
demonstrate the presence of voltage-operated calcium channels. Voltage-operated
calcium channels were stimulated by causing cell membrane depolarization either
by electrical field stimulation or extracellular high potassium. [Ca2+]i and cell
contraction were measured in individual cells loaded with fura-2 using a
morphometric method with an epifluorescence microscope coupled to a charge
coupled device-imaging system. RESULTS: Binding studies demonstrated the
existence of voltage-operated calcium channels in human activated hepatic
stellate cells (7.1+/-1.4x10(4) sites/cell with a Kd of 2.1+/-0.1 nM). Both
electrical field stimulation and potassium chloride-induced cell depolarization
resulted in a marked and prolonged increase in [Ca2+]i followed by intense cell
contraction. The degree of cell contraction correlated with the intensity of
calcium peaks. Removal of extracellular calcium or preincubation of cells with
nitrendipine, a specific antagonist of voltage-operated calcium channels,
completely blocked the effects on [Ca2+]i and cell contraction, whereas
preincubation of cells with BayK-8644, a specific agonist of voltage-operated
calcium channels, increased calcium peaks and contraction. CONCLUSION: Activated
human hepatic stellate cells have a large number of voltage-operated calcium
channels, the activation of which is associated with an increase in [Ca2+]i
followed by marked cell contraction. Voltage-operated calcium channels probably
play an important role in the regulation of activated hepatic stellate cells
contractility.
PMID- 9764987
TI - Abnormal accumulation of endotoxin in biliary epithelial cells in primary biliary
cirrhosis and primary sclerosing cholangitis.
AB - BACKGROUNDS/AIMS: Previous studies have revealed the involvement of Kupffer cells
and hepatocytes in the metabolism of endotoxin in the liver. The aim of this
study was to investigate the in vivo localization of endotoxin in liver cells,
including Kupffer cells, hepatocytes, and biliary epithelial cells, in primary
biliary cirrhosis and primary sclerosing cholangitis. We also examined the effect
of ursodeoxycholic acid on the intrahepatic distribution of endotoxin in primary
biliary cirrhosis. METHODS: The immunohistochemical localization of endotoxin was
examined in liver specimens from 30 cases of primary biliary cirrhosis and seven
of primary sclerosing cholangitis using a monoclonal antibody against lipid A.
Controls were seven cases of obstructive jaundice, ten of hepatitis C virus
related liver cirrhosis, 14 of chronic hepatitis C, and five histologically
normal liver cases. Semi-quantitative analysis of endotoxin accumulation was
performed to measure the intensity of fluorescence for endotoxin. Nine of the 30
patients with primary biliary cirrhosis underwent a second liver biopsy for
evaluation of the ursodeoxycholic acid treatment. RESULTS: In primary biliary
cirrhosis and primary sclerosing cholangitis, biliary epithelial cells showed
strong immunostaining for endotoxin as well as hepatocytes and Kupffer cells.
Biliary epithelial cells of primary biliary cirrhosis and primary sclerosing
cholangitis showed more intense immunoreactivity than those of other controls. In
primary biliary cirrhosis, ursodeoxycholic acid reduced the immunoreactivity to
endotoxin in biliary epithelial cells, and increased the immunoreactivity to
endotoxin in Kupffer cells, but did not affect that in hepatocytes. CONCLUSIONS:
Our results revealed that in primary biliary cirrhosis and primary sclerosing
cholangitis, endotoxin accumulates abnormally in biliary epithelial cells. In
addition, we found that ursodeoxycholic acid treatment in primary biliary
cirrhosis may provide a beneficial effect on the intrahepatic metabolism of
endotoxin.
PMID- 9764989
TI - Polyethylene glycol-modified bilirubin oxidase improves hepatic energy charge and
urinary prostaglandin levels in rats with obstructive jaundice.
AB - BACKGROUNDS/AIMS: No study has so far been conducted to clarify whether the
presence of hyperbilirubinemia is detrimental to liver and renal functions. In
the present study, the effects of polyethylene glycol-modified bilirubin oxidase
(PEG-BOX) therapy on liver and renal function tests, hepatic energy charge and
urinary prostaglandin levels were evaluated in a rat model of obstructive
jaundice. METHODS: Sprague-Dawley rats were used in the experimental model of
obstructive jaundice. PEG-BOX or an equivalent amount of PEG alone was
intravenously injected into the animals and sampling of blood and urine, and
liver harvesting were done sequentially after bile duct ligation. RESULTS:
Conventional liver function tests showed no difference between PEG-BOX and
control groups. However, bilirubin concentrations in the peripheral blood and
liver tissue specimens markedly decreased, and the hepatic energy charge
significantly increased in the PEG-BOX group as compared to controls. The blood
concentration of bile acid was lower, but its urinary excretion was higher in the
PEG-BOX group than in the control group. In vitro incubation of PEG-BOX with
serum from rats with obstructive jaundice decreased the concentration of
bilirubin but not that of bile acid. The urinary levels of prostaglandin E2 and
the thromboxane B2/6-keto-prostaglandin Fla ratio were significantly lower in the
PEG-BOX group than in the control group. CONCLUSIONS: The systemic reduction of
bilirubin concentration may contribute to normalization of the urinary levels of
prostaglandins and thromboxane B2, to decrease in serum bile acid levels, and to
improvement of the hepatic energy charge in obstructive jaundice. These findings
suggest that preoperative improvement of jaundice may be beneficial to patients
with obstructive jaundice.
PMID- 9764988
TI - Ursodeoxycholic acid therapy for primary sclerosing cholangitis: results of a 2
year randomized controlled trial to evaluate single versus multiple daily doses.
AB - BACKGROUND/AIMS: Ursodeoxycholic acid has been reported to be of potential
benefit for primary sclerosing cholangitis but little is known about the long
term biochemical, histological and radiological efficacy or the optimum frequency
of ursodeoxycholic acid administration. METHODS: A 2-year multicentre randomised
controlled trial was initiated to assess the effects of ursodeoxycholic acid (10
mg kg(-1).d(-1), given in either single or multiple daily doses, on symptoms,
serum liver tests, cholangiographic and histological findings and the occurrence
of treatment failure. Liver biopsies were taken and endoscopic retrograde
cholangiography was performed at entry and after 2 years; follow-up examinations
were at 3-month intervals. Treatment failure was defined as death, liver
transplantation, 4-fold increase in serum bilirubin, variceal bleeding, de novo
ascites or cholangitis. Actuarial survival was compared with predicted survival
using the revised Mayo natural history model for primary sclerosing cholangitis.
RESULTS: Forty-eight patients were enrolled. In one case, ursodeoxycholic acid
had to be discontinued because of gastro-intestinal complaints. No other side
effects were observed. After 2 years of follow-up, treatment was not associated
with a beneficial effect on either symptoms or liver histology. Serum liver tests
(alkaline phosphatase, y-glutamyl transferase, aspartate aminotransferase)
improved significantly in both groups, while serum bilirubin (which was near
normal at entry) and IgG remained stable. No major changes in radiographic bile
duct appearance seemed to be present. After 2 years, actuarial survival was 91%
(95 CI 83%-99%), which is comparable to the predicted 97% survival rate.
Treatment failure occurred in 15% of cases. No significant differences in any of
the study endpoints (symptoms, serum liver tests, cholangiographic findings,
histology, disease progression) were found between the two groups. CONCLUSIONS:
Ursodeoxycholic acid is well tolerated in primary sclerosing cholangitis.
Significant effects on biochemical parameters were found and symptoms, bilirubin
and histology did not deteriorate. No advantage of a multiple daily dose over a
single dose was observed.
PMID- 9764990
TI - Norfloxacin primary prophylaxis of bacterial infections in cirrhotic patients
with ascites: a double-blind randomized trial.
AB - BACKGROUND/AIMS: Norfloxacin is useful to prevent infections in hospitalized
cirrhotic patients with low ascitic fluid protein concentrations. It is also
effective in preventing the recurrence of spontaneous bacterial peritonitis. The
aim of our study was to determine the efficacy of norfloxacin in the primary
prophylaxis of gram-negative bacilli infections in cirrhotic patients with low
ascitic fluid protein levels (<15 g/l). METHODS: One hundred and seven patients
were randomized to receive norfloxacin (400 mg/day; n=53) or placebo (n=54) for 6
months. The patients had no history of infection since cirrhosis diagnosis and no
active infection. RESULTS: The probability of gram-negative infection was
significantly lower among patients treated with norfloxacin than among those
treated with placebo. Six gram-negative bacilli infections occurred in the
placebo group and none in the treatment group. Severe infections (spontaneous
bacterial peritonitis, neutrocytic ascites and bacteremia) developed in nine
patients in the placebo group (17%) and in one patient in the norfloxacin group
(2%; p<0.03). There was no between-group difference in the overall rate of
infection or in survival. In ten patients from the norfloxacin group, gram
negative bacilli not present in baseline stool cultures were transiently isolated
in follow-up cultures. CONCLUSIONS: These data show that primary prophylaxis with
norfloxacin for 6 months is effective in the prevention of infections caused by
gram-negative bacilli in cirrhotic patients with low ascitic fluid total protein
levels.
PMID- 9764991
TI - Effects of oral ciprofloxacin on aerobic gram-negative fecal flora in patients
with cirrhosis: results of short- and long-term administration, with daily and
weekly dosages.
AB - BACKGROUND/AIMS: Selective intestinal decontamination has been proposed to
prevent spontaneous bacterial peritonitis in cirrhosis. Because of the cost of
antibiotics and the development of resistant bacteria, we have evaluated the
effect of different schemes and doses of oral ciprofloxacin on aerobic gram
negative fecal flora in cirrhotic patients. METHOD: Twenty-nine cirrhotic
patients were allocated to four groups to receive: Group 1: 500 mg/day for 2
weeks (six patients); Group 2: 1000 mg twice a week for 2 weeks (six patients);
Group 3: 1000 mg once a week for 2 weeks (six patients); and Group 4: 1000 mg
once a week for 12 weeks (11 patients). Quantitative analysis of the gram
negative fecal flora was performed before and 1 and 2 weeks after initiation of
treatment in patients in Groups 1, 2 and 3 and before and 4, 8 and 12 weeks after
initiation of treatment in patients in Group 4. RESULTS: Complete eradication of
gram-negative bacilli was observed in four of six patients in Group 1. In
contrast, only one patient eradicated gram-negative bacilli in Group 2 and Group
3. In long-term administration of ciprofloxacin (Group 4), only two of 11
patients had persistent eradication of gram-negative bacilli. Four patients
developed E. coli resistant to ciprofloxacin (one of them associated to resistant
Klebsiella). No patient developed bacterial infection during the study period.
CONCLUSION: Oral ciprofloxacin administered in a weekly dose is ineffective in
selective intestinal decontamination. Different mechanisms, including the
emergence of ciprofloxacin-resistant organisms, could account for this failure.
Therefore, our results suggest that weekly administration of ciprofloxacin is not
useful in preventing spontaneous bacterial peritonitis.
PMID- 9764992
TI - Bright basal ganglia in T1-weighted magnetic resonance images are frequent in
patients with portal vein thrombosis without liver cirrhosis and not suggestive
of hepatic encephalopathy.
AB - BACKGROUND/AIMS: Deposition of paramagnetic substances in basal ganglia,
resulting in increased signals in T1-weighted magnetic resonance images (bright
basal ganglia), is frequently seen in liver cirrhosis. The present study
describes the prevalence of bright basal ganglia and its clinical significance in
patients with long-standing portal vein thrombosis in the absence of liver
cirrhosis. METHODS: Six patients with angiographically proven complete portal
vein thrombosis and cavernomatous transformation without signs of acute or
chronic liver disease were studied by magnetic resonance imaging of the brain,
neuropsychiatric evaluation, psychometric tests, electroencephalography, and
determination of arterial ammonia levels and of serum manganese concentrations
from peripheral venous blood. RESULTS: Five out of six patients demonstrated
increased signal intensity in the basal ganglia. Overt portal-systemic
encephalopathy was not noted prior to or at the time of evaluation. Normal EEG
results were recorded in all patients. Only one of the six patients had
pathological results in at least two out of four psychometric tests. This latter
patient had had a large right-sided brain infarction. Arterial ammonia
concentrations were normal in four of the six patients; one patient with
increased ammonia levels had concomitant renal insufficiency with azotemia. The
other four patients had no relevant concomitant diseases. Serum manganese levels
were non-significantly increased compared with a control group (p=0.06), but they
were significantly correlated to basal ganglia signal intensity (R=0.88; p=0.02).
CONCLUSIONS: Our results demonstrate that bright basal ganglia primarily
represent shunt-induced alterations. They are not directly associated with
disturbed liver function nor with portal-systemic encephalopathy.
PMID- 9764994
TI - Hepatic OV-6 expression in human liver disease and rat experiments: evidence for
hepatic progenitor cells in man.
AB - BACKGROUND/AIMS/METHODS: Since in rat experiments, activation of progenitor cells
is seen in conditions associated with hepatocyte injury or inhibited replication,
we compared the activation and fate of human putative progenitor cells in
regenerating liver versus chronic cholestatic disease, using
immunohistochemistry, rat oval cell marker OV6 and a panel of bile ductular cell
markers. We compared the results with different rat models: the choline-deficient
acetylaminofluorene (CDAAF)- and alpha-naphthylisothiocyanate (ANIT)-model, using
immunohistochemistry and electron microscopy. RESULTS: In very early stages of
human liver regeneration, putative progenitor cells in the vicinity of portal
tracts were immunoreactive for OV6, CK7, CK19 and chrom-A. In later stages of
regeneration and in chronic cholestasis, reactive bile ductules (immunoreactive
for OV6, CK7, CK19, chrom-A, NCAM) and intermediate hepatocyte-like cells
(immunoreactive for OV6, CK7, chrom-A), became apparent, suggesting bidirectional
differentiation of the putative progenitor cells. In regenerating human liver,
intermediate hepatocyte-like cells became more numerous with time and extended
far into the lobule. In advanced cholestasis, intermediate hepatocyte-like cells
were less numerous and formed periportal rosettes and small clusters. In the
CDAAF rat model (associated with inhibited hepatocyte replication), but not in
the ANIT model, gradual differentiation of oval cells into hepatocytes was seen
after stopping the diet. CONCLUSIONS: Our results in human liver suggest that
reactive ductules and intermediate hepatocyte-like cells originate at least
partly from activation and differentiation of "progenitor cells". In regeneration
after submassive necrosis, in analogy with what is seen in rat models,
differentiation towards hepatocytes is more pronounced than in chronic
cholestasis.
PMID- 9764993
TI - Isolation from human fetal liver of cells co-expressing CD34 haematopoietic stem
cell and CAM 5.2 pancytokeratin markers.
AB - BACKGROUND/AIMS: Ductal plate and bile duct cells in developing human liver
express haematopoietic stem cell markers, such as c-kit and CD34, in association
with cytokeratin markers CAM 5.2 and CK 18. The identification of such ductal
plate cells as likely progenitors for both bile duct epithelial cells and
hepatocytes and their possible reappearance as oval cells in the regenerating
liver have generated much interest in their pluripotential capacities. This study
aimed to isolate cells from human fetal liver that co-express haematopoietic stem
cell and epithelial cell markers. METHODS: Human fetal liver was harvested
following legal termination of pregnancy at week 14-22. CD34+ mononuclear cells
were isolated from liver cell suspensions with immunomagnetic beads.
Immunofluorescent staining, using anticytokeratin CAM 5.2 against CK 8 and 18,
was performed on permeabilised CD34+ cells for flow cytometry and fluorescent
microscopy. CD34+ cells were also stained for other stem cell markers (HLA-DR, c
kit) and committed haematopoietic cell markers (CD33, CD38). RESULTS:
Approximately 0.9% (range 0.07-4.0%) of the mononuclear cells isolated were CD34+
cells. The number of mononuclear cells isolated correlated with fetal liver
weight (r=0.508). About 3-8% of these CD34+ cells stained positively for CAM 5.2.
In addition, CD34+ cells were positive for HLA-DR, but only a small percentage
was positive for c-kit. Staining for the committed haematological markers, CD33
and CD38, was consistently negative. CONCLUSIONS: This study describes an
immunoaffinity method for the enrichment from human fetal liver of cells that co
express haematopoietic stem cell and epithelial cell markers. Such cellular
subsets may correspond to pluripotential ductal plate and bile duct cells.
PMID- 9764995
TI - Time course of cell cycle-related protein expression in diethylnitrosamine
initiated rat liver.
AB - BACKGROUND/AIMS: Cell cycle control and the relationship that exists between
cellular proliferation, the expression of cell cycle control proteins and cancer
have been reported. This study was designed to decipher the timing of cell cycle
control protein expression during the initiation of diethylnitrosamine-induced
rat hepatocarcinogenesis. METHODS: Three-week-old female Sprague-Dawley rats were
intraperitoneally injected twice in 1 week with diethylnitrosamine; after the
second injection, all animals were sacrificed at 1, 2 and 24 h, and 3 and 7 days.
The expression of cell cycle-related proteins such as CDK2 and 4, cyclin proteins
(D1, E and cdc2), proliferating cell nuclear antigen, tumor suppressor proteins
(p53 and Rb), CDK inhibitory proteins (p21waf1 and p27Kip1), and apoptosis
inhibiting protein (bcl-2) following diethylnitrosamine treatment was examined.
RESULTS: The peak induction time of each cell cycle-related protein during DEN
induced cellular proliferation was diverse, and expressions of CDK2, CDK4, cdc2,
p53, bcl-2, p21Waf1 and p27Kip1 appear to be of the greatest interest.
CONCLUSIONS: Data generated from this study may provide information about cell
cycle-related protein expression in the initiation stage of hepatocarcinogenic
signaling pathways stimulated by a genotoxic agent such as diethylnitrosamine.
PMID- 9764996
TI - Angioarchitecture and blood circulation in focal nodular hyperplasia of the
liver.
AB - BACKGROUND/AIMS: We sought to clarify important unresolved points regarding
angioarchitecture and blood circulation in focal nodular hyperplasia. METHODS:
Twenty-nine surgically resected focal nodular hyperplasia lesions were examined
histologically, immunohistochemically, and radiologically. In three autopsy
cases, red- and blue-colored gelatin was injected into the hepatic artery and the
portal vein, respectively, to demonstrate the vasculature in focal nodular
hyperplasia. RESULTS: Histologically, no orientation with respect to portal
tracts and central veins was evident in any lesion. Within lesions, vessels were
classified as: (i) anomalous arteries in the fibrous septa, (ii) capillaries in
the fibrous septa, or (iii) venous vessels located mainly in the parenchyma.
Vessels and sinusoids adjacent to fibrous septa were stained for CD 34 and von
Willebrand factor. The anomalous arteries were connected to the capillaries.
Capillaries in the fibrous septa were connected to sinusoids adjacent to fibrous
septa. Venous vessels were connected to central or hepatic veins surrounding the
lesions. Intranodular sinusoids were connected to the sinusoids in the
surrounding normal liver. Red-colored gelatin, injected at autopsy into the
hepatic artery, appeared not only in the anomalous arteries but also in
capillaries and in sinusoids adjacent to the fibrous septa of the lesion.
Angiography clearly depicted hepatic veins located near the lesions in nine
cases. Computed tomography during arterial portography disclosed no portal blood
flow in the lesions. CONCLUSIONS: In focal nodular hyperplasia, arterial blood
flows from the anomalous arteries via the capillaries into sinusoids adjacent to
fibrous septa. The blood in the sinusoids drained to the hepatic vein either
directly or via perinodular sinusoids.
PMID- 9764997
TI - Kinetic analysis of vascular marker distribution in perfused rat livers after
regeneration following partial hepatectomy.
AB - BACKGROUND/AIMS: Liver clearance models are based on information (or assumptions)
on solute distribution kinetics within the microvasculatory system. The aim was
to study albumin distribution kinetics in regenerated livers and in livers of
normal adult rats. METHODS: A novel mathematical model was used to evaluate the
distribution space and the transit time dispersion of albumin in livers following
regeneration after a two-thirds hepatectomy compared to livers of normal adult
rats. Outflow curves of albumin measured after bolus injection in single-pass
perfused rat livers were analyzed by correcting for the influence of catheters
and fitting a long-tailed function to the data. RESULTS: The curves were well
described by the proposed model. The distribution volume and the transit time
dispersion of albumin observed in the partial hepatectomy group were not
significantly different from livers of normal adult rats. CONCLUSIONS: These
findings suggest that the distribution space and the transit time dispersion of
albumin (CV2) is relatively constant irrespective of the presence of rapid and
extensive repair. This invariance of CV2 implies, as a first approximation, a
similar degree of intrasinusoidal mixing. The finding that a sum of two (instead
of one) inverse Gaussian densities is an appropriate empirical function to
describe the outflow curve of vascular indicators has consequences for an
improved prediction of hepatic solute extraction.
PMID- 9764998
TI - Lipoamide dehydrogenase deficiency: a newly discovered cause of acute hepatitis
in adults.
AB - Lipoamide dehydrogenase deficiency is a rare disease, manifested in early
childhood by lactic acidemia, progressive neurological damage and death in most
cases. We report a case of lipoamide dehydrogenase deficiency in a 34-year-old
Ashkenazi-Jewish woman. The deficiency manifested as acute hepatitis without
cognitive impairment or acidosis. The patient's brother also had lipoamide
dehydrogenase deficiency, diagnosed at the age of 20, and manifested as
hepatocellular damage, lactic acidemia and myoglobinuria. We assume that the
trigger for this hepatocellular damage was prolonged fasting, and that otherwise
the patient might have gone undiagnosed. Other cases in Ashkenazi Jews of mild
lipoamide dehydrogenase deficiency with hepatocellular injury but without central
nervous system involvement are reviewed.
PMID- 9764999
TI - Primary lymphoma of the liver with bile duct invasion and tumoral occlusion of
the portal vein: report of a case.
AB - A 55-year-old woman presented to hospital with epigastric pain and jaundice.
Diagnostic imaging studies revealed a biliary stricture of the hepatic confluence
and a hepatic tumour of the left and caudate lobes with a portal tumour thrombus,
which occupied the main portal trunk, the umbilical portion of the left portal
vein, and the right anterior and posterior portal branches. Left hepatic
trisegmentectomy, caudate lobectomy, portal tumour thrombectomy, bile duct
resection and bilioenteric anastomosis were performed. There were no other
lesions, and so it was diagnosed as a primary lymphoma of the liver (B-cell,
diffuse, large cell type). The patient underwent postoperative chemotherapy and
has remained well for 4.5 years after surgery. Primary lymphoma of the liver is
very rare, and this is the first case report with bile duct invasion and tumoral
occlusion of the portal vein.
PMID- 9765000
TI - Wilson's disease before and after 5 years of treatment with D-penicillamine.
PMID- 9765002
TI - Non-alcoholic steatohepatitis (NASH): a disease of emerging identity and
importance.
PMID- 9765001
TI - Antibiotic prophylaxis for spontaneous bacterial peritonitis: how and whom?
PMID- 9765003
TI - Hemochromatosis 1998: is one gene enough?
PMID- 9765004
TI - Clinical impact of lamivudine resistance in chronic hepatitis B.
PMID- 9765005
TI - Long-term efficacy of interferon alpha treatment in chronic hepatitis C.
PMID- 9765006
TI - Increased serum nitrite and nitrate concentrations in chronic hepatitis.
PMID- 9765007
TI - Hepatocellular carcinoma in patients suffering from primary sclerosing
cholangitis.
PMID- 9765008
TI - Malpractice claims for permanent nerve injuries related to third molar removals.
AB - On the basis of the register of the Finnish Patient Insurance Association, the
aim of this study was to examine malpractice claims for nerve injuries associated
with third molar removals and determine whether they are concentrated among
specialists, among less experienced dentists, or in certain geographic areas.
During 1987-93 there were 139 claims for permanent sensory or motor disturbances
related to removal of lower third molars in Finland. The lingual nerve was
injured in 54% and the inferior alveolar nerve in 41% of the claims. In 91% of
the cases the injury occurred in relation to surgical removal of the tooth and in
6% in relation to simple extraction. The claims were distributed among 123
dentists, of whom 78% were dental surgeons, 15% specialists in oral and
maxillofacial surgery, and 7% other specialists. These figures represented 2% of
the dental surgeons and 26% of the oral surgeons in Finland (P< 0.01). More than
half the claims were associated with dentists with less than 10 years'
experience. Claims originated more often from the eastern and northern (rural)
areas of Finland than from urban areas (3.8 claims versus 2.4 claims per 100,000
inhabitants, P < 0.05). Compensation was paid to the patients in two-thirds of
the cases, indicating that the dentists authorized to decide claims very often
considered these injuries avoidable. Therefore, proper diagnosis, treatment
planning, surgical techniques, and detailed patient information must be
emphasized. In cases where risks are obvious, referral to an oral surgeon is
recommended.
PMID- 9765009
TI - Effect of NaF-, SnF2-, and chlorhexidine-impregnated birch toothpicks on mutans
streptococci and pH in approximal dental plaque.
AB - The antimicrobial effect of birch toothpicks impregnated with 4% NaF, 8% SnF2, or
2% chlorhexidine was studied both in vitro and in vivo. A non-impregnated
toothpick served as a control. In vitro, suspensions of Streptococcus mutans were
exposed to the various toothpicks for 20 min and then cultured on blood agar. The
results of this susceptibility test revealed the following ranking order with
respect to inhibition: chlorhexidine > SnF2 > NaF and non-impregnated; with
significant differences in colony-forming units (CFU) between these three groups.
In vivo, 12 individuals used the 4 types of toothpick 3 times a day for 5 days in
a procedure with a crossover design. Saliva and approximal plaque samples were
collected at baseline and on various occasions up to 23 days after the treatment.
At the same time, plaque-pH was measured at approximal sites 10 min after rinsing
with 10% sucrose. The results of these in vivo experiments revealed lower
proportions of mutans streptococci after using all four types of toothpick, but
the reduction was significant only after 2 days for the toothpicks impregnated
with SnF2 and chlorhexidine (P< 0.05). On the sampling occasions 9 and 23 days
after the treatment, the mutans streptococci were more or less back to baseline
levels again. In saliva no significant differences in the number of mutans
streptococci were found either within or between the four treatments. No
significant differences were found regarding decline in the plaque-pH between the
NaF-, SnF2-, chlorhexidine-, and non-impregnated toothpicks on any of the
sampling occasions.
PMID- 9765010
TI - Fluconazole versus nystatin in the treatment of oral candidosis.
AB - The efficacy of oral fluconazole versus nystatin was evaluated as a treatment
modality for oral candidosis. Of the included patients (n = 60), two-thirds
presented with an erythematous candidosis, and the others showed clinical signs
compatible with a pseudomembranous candidosis. Predisposing factors were
xerostomia (n = 18), HIV (n = 5), immunosuppression in conjunction with organ
transplantation (n = 10), and wearing of dentures (n = 14). For the remaining
patients no specific predisposing factors were found. One patient who was treated
with nystatin was excluded owing to nausea that was related to the antifungal
treatment. After 7 days of treatment with fluconazole (50 mg/day), the affected
oral mucosa, assessed by the investigator, was cured or showed considerable
improvement in 87% of the patients (n = 30). The corresponding figure for the
nystatin group (n = 30), rinsing with 1 mL 4 times a day for 21 days, was 80%.
Following treatment with fluconazole, 20 of 22 patients with symptoms at the
start (91%) reported improvement. The comparable figures for the nystatin group
were 10 of 12 patients (83%). Half of the patients in the nystatin group reported
inconvenience from taking the medication (mean value = 25.9) compared with 23% of
the patients in the fluconazole group (mean value = 6.6). Eight patients in the
fluconazole group and 12 patients in the nystatin group exhibited a relapse
within 6 months. These differences were not found to be statistically
significant. The patients in the fluconazole group reported less inconvenience
from taking the medication, a finding that may have clinical implications for
compliance.
PMID- 9765011
TI - A descriptive study of how dentists view their profession and the doctor-patient
relationship.
AB - In this article we report on how 64 dentists working in a big city in southern
Sweden view their profession. The dentists ranged in age from 30 to 70 years (as
it was indicated in intervals of 10 years). Their professional experience ranged
from 2 to 44 years (mean, 23 years). We collected their views on the ideal skills
of a good dentist by means of a questionnaire. From this material we identified
three categories: 1) interpersonal skills; 2) clinical skills; and 3) others,
such as self-confidence, stress tolerance, and managerial and administrative
skills. Next, they rated the relative importance of a number of listed attributes
in dentistry in this order: contact with patients, communication skills, empathy,
manual skills, and theory. Finally, they described a number of aspects of their
profession. We conclude that the importance of interpersonal skills, as well as
stress tolerance and administrative skills, is emphasized by experienced
practitioners but that these skills are not focused on in the dental curriculum.
PMID- 9765012
TI - Viscosity of whole saliva.
AB - This study investigates within-subject variations and associations of salivary
viscosities and flow rates in a test panel of healthy adults. After several
practice sessions, unstimulated and stimulated whole saliva samples were
collected 5 times daily (at 0800, 1100, 1400, 1700, and 2000 h) from 30
university students. There was a significant within-subject variation in
viscosity and flow rate of unstimulated saliva (P<0.001). Intra-item correlations
were significantly different for salivary flow rates (r= 0.82 for unstimulated,
r= 0.88 for stimulated, P< 0.001) and viscosity of unstimulated saliva (r= 0.54,
P< 0.05), but viscosity of stimulated saliva was different in this respect. Our
results indicate that there is a significant within-subject variation in
viscosity of unstimulated saliva.
PMID- 9765013
TI - A logistic regression model for analyzing the relation between dentists'
attitudes, behavior, and knowledge in oral radiology.
AB - The aim was to study the relation between risk attitude and knowledge in
technical, patient-oriented, and organizationally related behavior within oral
radiology. A questionnaire was mailed to 2000 randomly selected dentists listed
in the register of the Swedish Dental Society, with a response rate of 69.3%.
Regression analysis was used for analyzing the effects of the independent
variables knowledge, risk attitude, continuing education in oral radiology,
counties with specialists in oral radiology, type of practice, work experience,
and sex on three categories of dependent variables: 1) technical behaviors: type
of film, type of collimator, dose level, frequency of change of chemicals; 2)
patient-oriented behaviors: use of patient protection barriers, strict
indications for performing full-mouth X-ray examinations and bitewing radiography
on new patients and recall patients; and 3) organizationally related behaviors:
delegation of X-ray examinations to dental auxiliaries, influence on choice of
collimator, influence on choice of film. Knowledge and education had strong
direct effects for most of the dependent variables. The technical behaviors were
mainly influenced by knowledge, education, and risk attitude, while
organizationally related behaviors were influenced by type of practice and sex.
The patient-oriented behaviors were influenced by a number of independent
variables, such as education, type of practice, work experience, and sex. The
present results indicate that both knowledge and the organizational context of
dentists influence work.
PMID- 9765014
TI - Nerve fibers immunoreactive to calcitonin gene-related peptide, substance P,
neuropeptide Y, and dopamine beta-hydroxylase in innervated and denervated oral
tissues in ferrets.
AB - The effect of sensory and sympathetic denervation on the localization and
distribution of nerve fibers immunoreactive (IR) to calcitonin gene-related
peptide (CGRP), substance P (SP), neuropeptide Y (NPY), and dopamine beta
hydroxylase (DBH) was studied in the dental pulp, periodontal ligament (PDL), and
gingiva in ferrets. Unilateral axotomy was performed by resection of the inferior
alveolar nerve (IAN) 10 days before the experiment (Group 1); sympathectomy, by
unilateral removal of the cervical ganglion 5 days before the experiments (Group
2). Immunohistochemistry was performed on free-floating sections by the avidin
biotin-peroxidase technique. A considerably higher density of sensory fibers IR
to CGRP and SP was found in the dental pulp than in PDL and gingiva. The majority
of pulpal fibers were located in the walls of blood vessels. A subodontoblastic
network of fibers IR to CGRP and SP was lacking in incisors and canines and was
found only in the coronal pulp in premolars and molars. Sympathetic fibers were
sparsely distributed in the pulp, and they were mainly confined to large vessels
running centrally in the root pulp as well as the larger vessels in apical PDL
and alveolar bone. Gingiva was well supplied with CGRP- and SP-IR nerves, and
some NPY and DBH fibers were located in association with larger vessels. Round
cell-like structures within the basal part of the epithelium were CGRP-IR.
Axotomy induced a complete loss of CGRP- and SP-IR fibers in the anterior part of
the jaws, whereas sympathectomy caused a reduction, but not a total loss, of NPY-
and DBH-IR nerves. It is concluded that, except for some distributional
differences, the oral tissues in the ferret have an abundant sensory innervation
similar to that found in other species.
PMID- 9765015
TI - Acceptance of dental care following early extractions under rectal sedation with
diazepam in preschool children.
AB - The aim of the study was to evaluate the effect of amnesia in preschool children
on their later acceptance of dental care. Forty-six 4-6-year-old children, who
between 2 and 4 years previously had had primary incisors extracted because of
trauma, were reexamined for dental health and acceptance of dental care. The
extractions had been performed under rectal sedation with diazepam (0.7 mg/kg
body weight). Information about dental treatment and degree of cooperation during
the intervening period was obtained from records at the referring clinic. The
parents were interviewed about their child's experience of amnesia concerning the
extractions, background variables, and experiences of dental care before the
follow-up examination. Amnesia concerning the extractions was reported in 85% of
the children. Twenty-nine percent had on some occasion exhibited behavior
management problems (BMP) during the intervening period. Lack of amnesia was
significantly associated with BMP (P< 0.002). Children without amnesia concerning
the extractions tended to accept dental care less well at the reexamination.
Parents were able to predict their child's acceptance of dental care at the
follow-up with a significant degree of success (P= 0.02). In conclusion, amnesia
in preschool children concerning extractions seems to be essential to facilitate
positive acceptance of future dental care.
PMID- 9765016
TI - Prolonged pacifier-sucking and use of a nursing bottle at night: possible risk
factors for dental caries in children.
AB - At the baseline of this cohort study we determined risk factors for colonization
of oral lactobacilli and candida in a group of children (n = 166) whose mean age
was 2.5 years. The results showed that pacifier-sucking and the use of a nursing
bottle at night increase the occurrence of both salivary lactobacilli and
candida. In the present study these children were followed for 2 years, and the
progression of caries was recorded with particular reference to the etiologic
factors measured before. The results of the logistic regression analysis showed
prolonged pacifier-sucking (> or = 24 months) to be a significant risk factor for
caries development in children, with a rather high relative risk (RR) of 3.5 (95%
confidence interval (CI), 1.5-8.2; P= 0.003). Prolonged use of a nursing bottle
at night (> or = 24 months) was also a risk factor, but less significant than
pacifier-sucking (RR, 2.6; CI, 1.1-6.4; P= 0.03). On the grounds of this study we
conclude that prolonged pacifier-sucking (> or = 2 years) and use of a nursing
bottle at night are risk factors for dental caries in children.
PMID- 9765017
TI - Validity of the Demirjian method for dental age estimation when applied to
Norwegian children.
AB - Dental age was studied in a sample of 261 Norwegian children by using the
maturity standards of Demirjian & Goldstein (1976) to examine the applicability
of these standards as a reference for overall dental maturity in a Norwegian
population. The sample comprised 128 boys and 133 girls included in 'the Oslo
Growth Material', from whom orthopantomograms (total, 783) had been
longitudinally obtained, with intervals of about 3 years and covering 3 age spans
(5.5-6.5 years, 8.5-9.5 years, and 11.5-12.5 years), each divided into 3 half
year age groups. Reliability was analyzed by repeated assessments of 134 of the
radiographs, and the overall mean difference between duplicate dental age
determinations was 0.5 months for intra- and 1.8 months for inter-examiner
comparisons. The Norwegian children were generally somewhat advanced in dental
maturity compared with the French-Canadian reference sample. Among the boys the
mean difference between dental age and chronologic age varied in the different
age groups from 1.5 to 4.0 months. Among the girls the difference increased with
age, varying from 0 to 3.5 months in the younger age groups (5.5 to 9.0 years)
and from 4.5 to 7.5 months in the age groups 9.5 years and above. The variability
in individual dental age was marked and increased with age. For the older age
groups 95% of the individual age estimates were within +/-2 years of the real
age. The applied standards appear to be adequate for studying dental age in
groups of children from a Norwegian population. Given the considerable individual
variation in dental maturity, estimation of chronologic age in individual
children should be supplemented by other indicators of biologic maturity.
PMID- 9765019
TI - The trichofolliculoma undergoes changes corresponding to the regressing normal
hair follicle in its cycle.
AB - The trichofolliculoma is a follicularly differentiated hamartoma, usually
described as showing many vellus follicles, spreading from a central infundibular
cyst. In spite of the well known regressive changes of normal hair follicles
during catagen and telogen, the possibility of corresponding changes in the
trichofolliculoma has not yet been discussed in the literature. By examining a
total of 31 cases of trichofolliculoma it is demonstrated that this hamartoma
undergoes an evolutionary process with great morphological changes, which can be
attributed to the anagen, catagen, and telogen phase of the follicular cycle.
PMID- 9765018
TI - Physicomechanical and cytotoxic properties of room temperature vulcanizing
silicone prosthetic elastomers.
AB - The physicomechanical and cytotoxic properties of two newly introduced room
temperature vulcanizing (RTV) silicone prosthetic elastomers, Ideal and Silskin
2000, were investigated. Another RTV silicone, Elastosil M3500, was also
investigated as a potential facial material. The in vitro cytotoxicity was
assessed with the agar diffusion test and mouse fibroblast cells (L929). The
properties investigated were tensile strength, percentage elongation, modulus,
tear strength, hardness, and color changes (deltaE*). The properties tested were
selected because of their clinical significance in fabricating facial prostheses.
The results indicate that Elastosil M3500 has a better combination of high tear
strength, elongation at break, and low hardness than Ideal and Silskin 2000. All
materials demonstrated a low cytotoxic profile. Elastosil M3500 warrants further
attention with clinical trials.
PMID- 9765020
TI - Folliculo-sebaceous cystic hamartoma is a trichofolliculoma at its very late
stage.
AB - Folliculo-sebaceous cystic hamartoma (FCH) was described as an entity recently
and was defined as an adnexal hamartoma, showing above all an infundibular cystic
structure linked to many sebaceous lobules. Differentiation toward the inferior
segment of the hair follicle also occurs, although to a markedly lesser degree.
Signs of regression and rest corresponding to the normal follicular cycle are
often apparent in these follicular proliferations. Therefore so-called FCH has
much in common with the newly described late stage of trichofolliculoma, which
also exhibits an infundibular cyst and sebaceous and follicular differentiation
with various signs of catagen and telogen. Comparing our 8 cases of FCH and 31
cases of trichofolliculoma, we came to the conclusion that FCH is the very late
stage of trichofolliculoma. This stage could be characterized by a nearly
complete regression of the transient follicular epithelium, whereas concurrent
growth and maturation of sebaceous elements appear.
PMID- 9765021
TI - Cathepsin D expression in skin metastasis of breast cancer.
AB - Cathepsin D, an aspartic proteinase, correlates with invasion and metastasis in
breast cancer and with poor prognosis. In the present study, we examined the
immunohistological expression of cathepsin D in both primary (5 cases) and skin
metastatic breast cancers (13 cases) and compared it to those in gastric (2
cases) and lung (4 cases), and primary eccrine cancers (3 cases). All breast and
gastric cancers were adenocarcinomas. The 2 gastric cancers were poorly
differentiated, while the 4 lung cancers consisted of 2 poorly differentiated
adenocarcinomas, 1 poorly differentiated large cell carcinoma, and 1 moderately
to poorly differentiated squamous cell carcinoma. We also surveyed the
immunohistological distribution of cathepsin B, carcinoembryonic antigen, gross
cystic disease fluid protein-15, c-erbB-2, and estrogen receptor. In almost all
breast cancer samples, the cancer cells demonstrated strong expression of
cathepsin D in the cytoplasm, but weak staining patterns with other antibodies.
Gastric and lung cancer cells did not respond with cathepsin D (except one
metastatic lung cancer) or the other immunohistological markers. Since cathepsin
D is strongly expressed in primary and metastatic lesions of breast cancer,
cathepsin D could be useful as an adjunct to a panel of immunohistochemical
stains in determining the primary site of origin of metastatic cancer in the
skin.
PMID- 9765022
TI - Cutaneous Langerhans cell histiocytosis of the genitalia in the elderly: a report
of three cases.
AB - Langerhans cell histiocytosis (LCH) is a disease with a broad spectrum of
clinical presentations. All of the variants have in common the proliferation of
cells which are morphologically, biochemically, and immunophenotypically
indistinguishable from Langerhans cells. A retrospective study of three elderly
patients revealed the unique presentation of cutaneous Langerhans cell
histiocytosis limited to the genitalia. These cases produced a diagnostic
challenge because of their unusual clinical presentation and their morphological
similarity to certain other entities, including extramammary Paget's disease and
malignant melanoma, which may also show S-100-positive atypical cells. All three
cases showed infiltrates of histiocytic-appearing cells with folded nuclei and
moderate amounts of cytoplasm which involved the epidermis, dermis, or both.
Immunoperoxidase studies using antibody to S-100, CD1a and CD68 in each case
showed positive staining.
PMID- 9765023
TI - Numbers and differentiation status of melanocytes in idiopathic guttate
hypomelanosis.
AB - The etiology and pathogenesis of idiopathic guttate hypomelanosis (IGH) are
largely unknown. To investigate whether the pathologic alteration in IGH involves
changes in melanocytic differentiation, cell number, or both, we studied nine
lesions of IGH by immunoperoxidase, using monoclonal antibodies against the KIT
receptor and a panel of melanocyte differentiation antigens (tyrosinase-related
protein-1, tyrosinase, and gp100/pme117). In each case, compared with grossly
normal non-lesional skin, IGH lesions showed markedly reduced numbers both of
KIT+ cells and of cells expressing melanocyte differentiation antigens (p <
0.0001). Double immunofluorescence labeling of lesions revealed only scattered
cells with a less-differentiated phenotype, i.e. cells positive for KIT but
having low or undetectable TRP-1. These results indicate that the pathogenesis of
IGH involves an absolute decrease in the number of melanocytes; a block in
melanocyte differentiation does not appear to be a major component of the
process.
PMID- 9765024
TI - Hermansky-Pudlak syndrome: report of a case with histological,
immunohistochemical and ultrastructural findings.
AB - We report a 38-year-old female of Puerto Rican descent with Hermansky-Pudlak
syndrome and decreased levels of von Willebrand factor. Histologic and
ultrastructural findings of non-sunexposed skin showed melanocytes with short
dendritic processes and decreased numbers of melanosomes. Ultrastructural
examination of platelets revealed greatly reduced numbers of delta granules.
Recognition of this syndrome is important because skin neoplasms, ceroid
deposition and hemorrhagic manifestations can be causes of morbidity and of
potential death in patients affected with this syndrome.
PMID- 9765025
TI - Myxoid dermatofibrosarcoma protuberans: morphological, ultrastructural and
immunohistochemical features.
AB - Two uncommon cases of dermatofibrosarcoma protuberans with prominent myxoid
changes are presented. The tumors appeared as large multinodular cutaneous
plaques that arose at the sites of excision of previous tumors some years
earlier. In addition to limited fibrous storiform features, focally observed in
deep and peripheral portions of the tumors, a diffuse myxoid pattern could be
observed. The latter consisted of homogeneous areas of rare, stellate or spindle
shaped cells, haphazardly scattered in abundant myxoid matrix. Cells of myxoid
neoplastic tissue showed mainly a positive immunoreaction for fibrohistocytic
markers and the absence either of muscular, neural or human progenitor cell
antigens. Mitotic figures were fewer and cell proliferation rates were lower in
myxoid as compared to those of typical dermatofibrosarcoma protuberans used as a
control. The ultrastructural examination of myxoid areas revealed a prevalent
fibroblast-like cell population showing dilated cytoplasmic vesicles, sometimes
containing glycosaminoglycans-like substances. The extent of myxoid changes
together with the characteristic morphological, ultrastructural and
immunohistochemical features confirm that myxoid dermatofibrosarcoma protuberans
is a distinct variant of this fibrohistiocytic tumor to be considered in the
differential diagnosis among myxoid tumors of the skin.
PMID- 9765026
TI - Subcutaneous panniculitis-like T-cell lymphoma: further evidence for a distinct
neoplasm originating from large granular lymphocytes of T/NK phenotype.
AB - We report the case of a 20 year-old caucasian woman who presented a primary
subcutaneous panniculitis-like T-cell lymphoma (SPTCL) as an invasive tumor of
the chest wall. Herein, the neoplastic cells were found to express a CD3+CD8+
phenotype but also displayed variably the natural killer (NK)-associated antigens
CD56 and CD57 as well as granzyme B. On cytological examination, these cells
showed a large granular lymphocyte (LGL)-like morphology with presence of
azurophilic granules in their cytoplasm. Electron dense and membrane bound
granules like those found in cytotoxic T lymphocytes (CTL) were also demonstrated
by electron microscopy. Neither rearrangement of the T-cell receptor subunits nor
Epstein-Barr virus (EBV) genome was observed at the molecular level. The LGL-like
features of the neoplastic cells found in this case and the presence of NK
associated antigens provide additional support to the cytotoxic derivation of
most SPTCL.
PMID- 9765027
TI - DNA/genetic vaccination (minireview).
AB - An important new approach to vaccination is plasmid DNA injection in vivo that
can elicit an immune response against protein(s) encoded. Antigen that is
expressed from the in vivo transfected cells induces both humoral and cellular
immune response. DNA immunization is generally applicable for a wide range of
proteins. It can provide an organism with immunity against viruses, bacteria,
parasites, and tumors. DNA vaccines can overcome the disadvantages of vaccines
presently used as well as provide various new vaccines that are currently not
available. This minireview provides an overview of evaluated DNA vaccine
candidates against infectious agents and certain cancers.
PMID- 9765028
TI - Effect of plasmid DNA on immunogenicity of HBsAg-anti-HBs complex.
AB - Hepatitis B surface antigen (HBsAg) complexed with anti-HBs is more immunogenic
than HBsAg alone in mice. This complex is usually used with alum as an adjuvant,
which can enhance humoral response but inhibits cell-mediated immune responses.
To improve the immunogenicity of HBsAg-anti-HBs, we immunized mice with a
combination of this immunogenic complex and pCMVHBs, a plasmid encoding HBsAg, or
the vector pCMV. Both plasmids enhanced the anti-HBs response induced by the
immunogenic complex. We found 20 microg of plasmid or vector enhanced the anti
HBs response in all mice, whereas 1 microg was less effective. Splenocytes from
different immunized groups were stimulated with HBsAg in vitro, and the highest
level of IL-2 detected in the supernatant was found in mice immunized with HBsAg
anti-HBs plus pCMVHBs. A plasmid (pcDNA3c191) encoding core protein of hepatitis
C virus (HCV) was used as an adjuvant to the immunogenic complex. A preliminary
result showed that pcDNA3c191 not only enhanced the immunogenicity of HBsAg-anti
HBs, but also induced anti-HCV core antibodies. Immunization using a plasmid DNA
encoding one viral antigen in combination with antigen and antibody complex of
another microbial origin could be a new approach to the development of
multivalent vaccines.
PMID- 9765029
TI - The capacity of a combined liposomal hepatitis B and C vaccine to stimulate
humoral and cellular responses in mice.
AB - Combined hepatitis B surface antigen and hepatitis C antigen were encapsulated
into 1, 2, and 5 microm discrete liposomes and then lyophilized. Groups of
adolescent CD-1 mice were given a single 0.3 mL oral dose of these liposomes
containing 50 microg/mL hepatitis B surface antigen and hepatitis C antigen, 50
microg/mL of the same antigens or liposomes alone. Animals in each group were
sacrificed every 2 weeks for 10 weeks and the humoral response investigated by
enzyme-linked immunosorbent assay (ELISA) and the cellular response by splenic
lymphocyte proliferation to 10 microg of either antigen. Seroconversion to both
antigens in the mice receiving liposomal antigens occurred in 87.5% of animals
sacrificed at 4 weeks and later. One animal (12.5%) receiving antigen alone
seroconverted to hepatitis B virus at 6 weeks, but all animals receiving
liposomes alone remained negative. Proliferation indexes (PI) greater than 3 were
observed in all animals receiving liposomal antigens, with the greatest response
seen at 10 weeks. PI was less than 2 for all animals in the other two groups.
Thus, a single oral dose of liposomes of three sizes containing both hepatitis B
and C antigens given to mice resulted in rapid seroconversion and a progressive
robust cellular immune response, whereas the antigens alone or liposomes without
antigen did not.
PMID- 9765030
TI - Induction of immunity in the respiratory tract and protection from bovine
herpesvirus type 1 infection by different routes of immunization with recombinant
adenovirus.
AB - To investigate the capability of different routes of immunization with
replication-competent recombinant adenovirus to induce antigen-specific antibody
responses, we immunized cotton rats with a human adenovirus type 5 (HAd5) vector
expressing the glycoprotein D (gD) of bovine herpesvirus type 1 (BHV-1) (gD-dE3).
Different routes of mucosal and systemic immunization (intraduodenal-oral,
intraduodenal, intranasal and intradermal) with gD-dE3 stimulated similar levels
of gD-specific IgG in the serum of cotton rats. However, intranasal (i.n.)
immunization stimulated higher levels of gD-specific IgA in the lung and nasal
washes, and higher frequency of gD-specific antibody secreting cells in the lung
than did the intradermal immunization. Higher levels of antibody in the
respiratory tract following i.n. immunization correlated with better protection
of the lungs against i.n. BHV-1 challenge. Intraduodenal-oral immunization
induced more gD-specific antibodies in the respiratory tract than intraduodenal
immunization alone. Adenovirus dissemination to most organs tested was evident
following each route of immunization, which is important to consider when
studying the mechanism of induction of immunity by recombinant adenoviruses.
PMID- 9765031
TI - Point mutation of a rubella virus E1 protein T-cell epitope by substitution of
single amino acid reversed the restrictive HLA-DR polymorphism: a possible
mechanism maintaining HLA polymorphism.
AB - The influence of single amino acid substitutions within a rubella E1 protein T
cell epitope, E1(273-284) on T-cell recognition was studied. Substitutions of an
uncharged amino acid A for an E or for a T and substitution of a T for S were
found to not significantly reduce the T-cell responses. However, substitution of
a charged residue such as E for hydrophobic residues (I, V, or W); D for Q; or a
relatively larger size amino acid for polar residues completely abolished the
cytotoxicities mediated by E1(273-284)-specific T-cell clone. A set of single
amino acid-substituted peptide analogs of E1(273-284) not eliciting cytotoxicity
of the T-cell clone was used to test the influence of point mutation of the
epitope on HLA DR restrictions. A panel of B-cell lines with different DR4
subtypes was used as targets in cytotoxicity assays to determine the restrictive
HLA molecules. Results showed that modification of the T-cell epitope by point
mutation could reverse the HLA DR restriction from one allele to other alleles. A
model based on these results has been proposed to explain the mechanism balancing
major histocompatibility complex (MHC) polymorphism in outbred populations.
PMID- 9765032
TI - Hantavirus seropositivity in Israeli patients with renal failure.
AB - The hantavirus is known to cause hemorraghic fever with renal syndrome (HFRS),
which is widely spread in Europe and Asia. Several reports have shown an
association of hantavirus antibody titers and the occurrence of renal
dysfunction. From these observations, it appears that the virus is widely
distributed, and different strains prevail in various areas. In the present work
we studied 81 patients with end-stage renal-failure under hemodialysis (HD)
treatment, 55 with mild to moderate renal failure, and 50 healthy subjects for
the presence of antibodies to Hantaan and Puumala viruses. We found that 12.3% of
the hemodialysis patients and 9% of the mild to moderate renal failure patients
had elevated IgG anti-body titers to Puumala virus compared with 2% of the
controls. IgM antibodies to Puumala virus was principally elevated in patient
with chronic renal failure (CRF) not on hemodialysis (14.5%) compared with the
hemodialyzed (1.2%) and controls (0%) subjects. Hantaan virus IgG antibodies were
detected in 3.7% of the HD patients, 5.5% of the CRF not on HD, and in none of
the controls. IgM Hantaan antibodies were found only in the non-HD renal failure
patients. None of the sera were found to contain antibodies to phospholipids or
single-stranded DNA. These results emphasize the widespread nature of infection
with hantaviruses and imply that elaborate testing for these serologies should be
performed, especially in patients with unexplained renal failure.
PMID- 9765033
TI - Assessment of curve progression in idiopathic scoliosis.
AB - In a 5-year prospective study on idiopathic scoliosis, an attempt was made to
elucidate the natural history of the disease and to determine which factors
contribute to curve progression. A total of 85,622 children were examined for
scoliosis in a prospective school screening study carried out in northwestern and
central Greece. Curve progression was studied in 839 of the 1,436 children with
idiopathic scoliosis of at least 10 degrees detected from the school screening
program. Each child was followed clinically and roentgenographically for one to
four follow-up visits for a mean of 3.2 years. Progression of the scoliotic curve
was recorded in 14.7% of the children. Spontaneous improvement of at least 5
degrees was observed in 27.4% of them, with 80 children (9.5%) demonstrating
complete spontaneous resolution. Eighteen percent of the patients remained
stable, while the remaining patients demonstrated nonsignificant changes of less
than 5 degrees in curve magnitude. A strong association was observed between the
incidence of progression and the sex of the child, curve pattern, maturity, and
to a lesser extent age and curve magnitude. More specifically, the following were
associated with a high risk of curve progression: sex (girls); curve pattern
(right thoracic and double curves in girls, and right lumbar curves in boys);
maturity (girls before the onset of menses); age (time of pubertal growth spurt);
and curve magnitude (> or = 30 degrees). On the other hand, left thoracic curves
showed a weak tendency for progression. In conclusion, the findings of the
present study strongly suggest that only a small percentage of scoliotic curves
will undergo progression. The pattern of the curve according to curve direction
and sex of the child was found to be a key indicator of which curves will
progress.
PMID- 9765034
TI - Radiation protection of the ovaries in young scoliosis patients.
AB - Concerns in clinical practice arose over the amount of ovarian irradiation
received from X-ray examinations in females with scoliosis. This study was
instigated to assess the adequacy of ovarian protection in this young and
genetically vulnerable group of patients. A total of 283 plain films in 20
patients with scoliosis were reviewed. If the area immediately adjacent to the
medial wall of the acetabulum was clearly seen, then this was taken as indicative
of ovarian irradiation. In a separate study, the radiation dose in the centre of
the X-ray field on the surface of a tissue-equivalent anthropomorphic phantom was
measured using thermoluminescent dosimeters. Standard conditions for scoliosis X
ray examination were used. The average age of patients was 21.5 years. The mean
number of single X-ray exposures per patient was 14.1 over a mean of 44 months.
The mean measured entrance dose to the skin in the 20 patients was 0.08 mGy
(equivalent dose = 0.08 mSv). The mean percentage of examinations without lead
protection was 18% per patient (range 0-40%). This would have resulted in a mean
equivalent dose to the surface of the abdomen of 0.1 mSv per year per patient
from the unprotected examinations. The maximum dose received in 1 year was 0.6
mSv. The maximum dose to the unprotected ovary was estimated to be 0.05 mSv from
a single examination. The mean total cumulative ovarian dose was calculated as
180 microSv per patient (range 45-355 microSv) over the time period studied. The
findings of this study indicate that ovarian protection should be improved.
Reasons for this and suggestions for improvement are discussed.
PMID- 9765035
TI - Volumetric determination of normal and scoliotic vertebral bodies.
AB - A new method is presented for stereological evaluation of the volume of the
vertebral body in vivo. The height of the vertebral body is measured at three
standardised points on an anteroposterior radiograph and at two other points on a
lateral one. The area of the body is also measured using a special grid
superimposed on a CT scan from the middle part of the vertebra. The volume of the
vertebral body is then calculated using Cavalieri's principle for irregular
objects: V = delta a x H, where V is the volume of the vertebral body, delta a is
the mean cross-section surface area on the CT scan and H is the mean of the
heights at the five points on the radiographs, computed as mean weighted
circumferential height. The volume of one normal and one scoliotic vertebra was
evaluated in vitro using this formula. The obtained values were compared with the
values derived from serial CT scans of the two vertebrae. The results showed that
the volume of the normal vertebra measured with our new method was 15.9 cm3 and
measured with serial CT scans using the same grid it was 15.07 cm3. For the
scoliotic vertebra the values were 17.6 and 17.3 cm3, respectively. The degree of
accuracy of the measurements with the presented method as compared with the
serial CT method was 95% for the normal and 98.5% for the scoliotic vertebra. To
prove the clinical applicability of the method, the heights of the apical and of
the upper and the lower end vertebrae of the curve and the volume of the apical
vertebrae were evaluated in eight scoliotic girls (nine curves) before and 3
years after spinal instrumentation and posterior fusion. The results showed that
the mean circumferential height of the three vertebrae had increased
significantly at the last follow-up. The volume of the apical vertebra had also
increased, but the difference was not significant. It is concluded that the
described method is easy to apply and has satisfactory accuracy for in vivo
longitudinal studies of the volume of the vertebral body on radiographs and CT
scans.
PMID- 9765036
TI - Paraspinal muscle fibre type alterations associated with scoliosis: an old
problem revisited with new evidence.
AB - To establish the extent to which the paraspinal muscles are affected in
idiopathic scoliosis, samples from patients must be compared with controls of a
similar gender and age. To date, insufficient control data has been available for
these purposes. The aim of this study was to re-dress this tissue, in order to
identify whether one side of the apex of the scoliotic curve showed greater
muscular abnormalities than the other. Bilateral samples of the paraspinal
muscles were obtained during surgery from 14 female scoliosis patients, at the
apex of the scoliotic curve at T9-T11. Percutaneous muscle biopsy samples were
obtained from nine female volunteers, on the left side of the spine at T10.
Samples were prepared for routine histochemistry for the identification of muscle
fibre types. Fibre size was measured using computerised image analysis. Compared
with control muscle, there was a significantly lower proportion of type I (slow
twitch oxidative) fibres in the muscle on the concave side of the scoliotic
curve, but no difference on the convex side. The proportion of type IIB (fast
twitch, glycolytic) fibres was higher on both sides of the curve compared with
controls, with the effect being significantly more marked on the concave side.
The percentage of type IIA (slow-twitch, oxidative-glycolytic) fibres did not
differ between the groups, and neither did fibre size (although there was a
tendency for the controls to have larger type IIA fibres than the patients).
Collectively, the differences in fibre type size and distribution meant that on
the concave side the relative area of the muscle occupied by type I fibres was
smaller, and on both sides of the curve the relative area occupied by type IIB
fibres was greater and by type IIA fibres smaller, in comparison with controls.
In scoliosis, the spinal musculature is most affected on the concave side of the
curve's apex. The muscle adopts a 'faster', or more 'glycolytic' profile, which
would be consistent with a reduced low-level tonic activity of the muscle,
perhaps consequent to a local change in activity on this side of the spine
following progression of the curve. Less marked changes, in the same direction,
are also evident on the convex side; these may be the result of general disuse of
the paraspinal muscles associated with the spinal deformity.
PMID- 9765037
TI - Preoperative evaluation of activity and function in patients with paralytic
scoliosis.
AB - Preoperative evaluation of patients with paralytic scoliosis should take into
account the consequences of surgery on the every day life of the patient.
However, the parameters that are customarily used in these operations relate only
to very narrow measures such as the angle of scoliosis or kyphosis. The aim of
this study was to introduce a set of instruments appropriate for measuring both
function and activities in paralytic scoliosis patients. The study took as its
starting point the WHO International Classification of Impairments, Disabilities
and Handicaps (ICIDH), in which an activity is described at the level of the
individual and function at the level of the organ. A consecutive series of 100
paralytic scoliosis patients with 18 different diagnoses were evaluated
preoperatively with a set of instruments that had been specially developed at
Linkoping hospital, in which the variables are classified according to the system
used in the ICIDH. The set of instruments included general information and
evaluation of activities and function--sitting, balance, weight distribution to
sitting surface, angle of scoliosis, reaching, pain estimation, activities of
daily living (ADL) Barthel and ADL Klein and Bell, care given, time spent
resting, and seating supports). The results showed that patients with paralytic
scoliosis constitute a heterogeneous group in activities and function. Even when
the patients were grouped into four subgroups according to the Scoliosis Research
Society Classification, they remained very heterogeneous. However, reaching,
Klein and Bell Activities of Daily Living and pain could only evaluate patients
who could understand verbal instructions. In those who could not, assessment
relied more heavily on measures of function and level of dependence. It was
concluded that the choice of assessment must be guided by the patient's ability
to understand verbal instructions irrespective of his/her disorder. It is
important to use the three levels--impairments, disabilities and handicaps-- in
order to focus on the different outcomes in the two groups with respect to the
patient's total situation.
PMID- 9765038
TI - Plate fixation adds stability to two-level anterior fusion in the cervical spine:
a randomized study using radiostereometry.
AB - This study evaluated whether addition of a cervical spine locking plate (CSLP) in
two-level disc fusions improved the postoperative stability and reduced the time
to healing. Radiostereometric analysis was used to obtain precise recordings of
the three-dimensional motion between the fused vertebrae. Eighteen consecutive
patients were operated on with excision of two adjacent cervical discs and
anterior horseshoe grafting with autologous bone (Smith Robinson technique). Nine
patients were randomized to stabilization with autologous bone grafting and CSLP
plate fixation and nine patients to grafting without fixation. Clinical symptoms
in terms of pain in the neck and the arm were analysed preoperatively and after 1
year using a visual analogue scale (VAS). The patients operated without a plate
displayed increased rotations around the transverse axis, corresponding to the
development of a kyphosis [mean value no plate/plate 14.4 degrees/0.8 degrees
(repeated measure ANOVA: P < 0.01)]. The mean compression was 3.2 mm larger in
patients operated without a plate (repeated measure ANOVA: P < 0.01). Patients
operated without a plate had more arm pain at the 1-year follow up (P < 0.05,
Mann-Whitney U test). The VAS score for neck pain did not differ significantly
between the two groups. Plate fixation could not be demonstrated to increase the
healing rate, promote more rapid fusion or influence the frequency of graft
complications.
PMID- 9765039
TI - Occipito-cervical fusion using posterior titanium plates.
AB - Occipito-cervical fusion may be indicated for instability of the occipito
cervical junction or atlanto-axial spine secondary to a wide spectrum of
pathology. Many techniques exist to stabilize the spine until fusion is achieved.
Recent reports of plate fixation have been favorable. In this study we set out to
determine the effectiveness and advantages of titanium plate fixation when used
to stabilize the occipito-cervical junction. Thirteen patients with occipito
cervical instability or atlanto-axial instability underwent occipito-cervical
fusion using posterior titanium plates. The plates were contoured to the occipito
cervical junction and fastened to the skull with screws, and to the spine with
lateral mass screws. The patients were followed prospectively clinically and
radiographically to a minimum of 24 months. Outcome parameters included peri
operative morbidity and complications, hardware integrity, spinal alignment,
fusion, and neurological status. Twelve of thirteen patients went on to solid
fusion radiologically and clinically, and recovered or improved from their
myelopathy. One patient did not. Three patients had radiographic evidence that
two screws were loose and one screw was broken. There were no instances of plate
breakage. We conclude that titanium plate fixation of the occipito-cervical
junction is versatile and stable. The plates maintain axial correction and allow
for future MR imaging.
PMID- 9765040
TI - The stability of bone screws in the os sacrum.
AB - A variety of points of insertion and implantation techniques are recommended for
inserting screws into the os sacrum. On the basis of 16 complete human sacrum
specimens the following axial pull-out tests were performed: 1. Insertion of
convergent measuring screws, 6.0 mm and 7.0 mm in outside diameter respectively,
into the body of vertebra S1 using a monocortical and bicortical technique
respectively with perforation of the ventral cortex. 2. Insertion of divergent
screws into the ala sacralis at the level of S1 with 6-mm and 7 mm screws
respectively, using a monocortical technique without perforation of the ventral
cortex. 3. Insertion of convergent 6-mm screws into the body of vertebra S2 using
a monocortical and bicortical technique respectively with perforation of the
ventral cortex. The highest axial pull-out force was reached using convergent 6
mm screws inserted into the body of vertebra S1 using the bicortical technique
with perforation of the ventral cortex (2392.4 N). The use of a 7.0-mm screw in
the same implantation technique did not result in higher pull-out forces (2274.7
N). The monocortical technique reached a pull-out force of 1657.53 N with a 6-mm
screw and 1505.64 N with a 7-mm screw. Convergent insertion of 6-mm screws into
the body of S2 resulted in pull-out forces of 537.02 N using a bicortical and
only 297.71 N using a monocortical technique. Divergent insertion of screws into
the ala sacralis reached a maximal pull-out force of 495.47 N using 6-mm screws
and 449.79 N using 7-mm screws. These data resulted from a monocortical
implantation technique without perforation of the ventral cortex of the ala
sacralis. The results of the present biomechanical study show that convergent
bicortical implantation in the body of S1 is the most stable technique for screw
fixation in the sacrum. The use of 7-mm rather than 6-mm screws did not lead to
increased primary stability. Anatomic studies have shown that a safe area exists
in the region of the ventral promontory, so this implantation technique appears
to be unobjectionable.
PMID- 9765041
TI - Functional outcome after posterolateral spinal fusion using pedicle screws:
comparison between primary and salvage procedure.
AB - Lumbar spinal fusion is a commonly performed surgical procedure, yet both the
indications for its performance and its results remain controversial. It is
generally believed that apart from situations where obvious measurable
instability exists, a repeat surgical procedure such as spinal fusion does not
improve the functional outcome in more than an average of 50% of cases. The aim
of this study was to analyse functional outcome after posterolateral lumbar or
lumbosacral spinal fusion, comparing primary and salvage procedures. It was
designed as a prospective case/referent study with a 2-year follow-up. A total of
39 patients underwent a short posterior fusion with Cotrel-Dubousset (CD) pedicle
screw fixation after earlier surgery of the lumbar spine. Two patients were
erroneously omitted from the study at the index, so 37 patients were included in
the salvage group. In the same period, 69 patients underwent lumbar fusion with
pedicle screw fixation (CD) as primary surgery (referent group). Functional
outcome was assessed by means of the Dallas Pain Questionnaire preoperatively and
1 and 2 years postoperatively. Fusion rates were determined by ordinary X-ray
evaluation by two independent observers. Patients who had undergone previous
spinal surgery had a significant improvement in functional outcome in terms of
daily activity, work and leisure-time activities and anxiety/depression. With
regard to social functioning, a significantly inferior outcome was found after
the salvage procedure. The return-to-work rates at 2 years after surgery were 50%
in the salvage group and 53% in the referent group. There was a significant
correlation between radiological evaluation of the fusion mass and the functional
outcome. The fusion rate was 76% in the salvage group and 72% in the referent
group. This study demonstrates that a posterolateral spinal fusion can be
effectively used as a salvage procedure. The functional and radiological outcome
of the patients with revision surgery did not differ from those of the group of
patients who underwent primary surgery. There was, however a clear indication of
inferior social functioning after revision surgery.
PMID- 9765042
TI - Value of quantitative radionuclide bone scanning in the diagnosis of sacroiliac
joint syndrome in 32 patients with low back pain.
AB - A prospective study was performed to compare the results of quantitative
radionuclide bone scanning with those of sacroiliac joint anesthetic block in
patients with unilateral low back pain. Thirty-four subjects, forming the control
group, underwent quantitative radionuclide bone scanning of the sacroiliac
joints. The normal values in sacroiliac uptake difference were taken to be
between -1.7% and +6.2%. Thirty-two patients with chronic unilateral low back
pain underwent sacroiliac bone scanning and sacroiliac joint block. Six of the
seven patients with increased uptake > 6.2% on the painful side had at least 75%
pain reduction in response to the block. The sensitivity, specificity, and
positive and negative predictive values of the quantitative bone scanning in the
unilateral mechanical sacroiliac joint syndrome were 46.1%, 89.5%, 85.7%, and
72%, respectively.
PMID- 9765043
TI - Graded thoracolumbar spinal injuries: development of multidirectional
instability.
AB - Injuries of the thoracolumbar spine are serious, disabling, and costly to
society. These injuries vary from mild ligament tears to severe bony fractures.
Increased range of motion (ROM) and neutral zone (NZ) have been suggested as
indicators of the resulting clinical instability. The purpose of the present
study was to investigate the relative sensitivities and merits of the ROM and NZ
in relation to spinal injuries of the thoracolumbar junction. A graded spinal
trauma experiment was designed, in which the threshold of injury and injury
progression were examined. Ten thoracolumbar human spine specimens (T11-L1) were
traumatized using a high-speed incremental trauma model. The ROM and NZ, which
indicate altered mechanical properties, were determined for three physiological
motions: flexion/extension (FE), lateral bending (LB), and axial rotation (AR).
The injury threshold was found to be 84 J (or 84 Nm) by examining both ROM and NZ
for all motion types (P < 0.05), but the NZ was more sensitive. At the injury
threshold, the NZ showed an overall average increase of 566% above that of the
intact, while the equivalent increase in the ROM was only 94%. The NZ was also a
more sensitive parameter documenting the progression of the injury beyond the
injury threshold. After the maximum trauma of 137 J, the NZs for the three
motions (FE, LB, and AR) increased by 700%, 1700%, and 3000% above their
respective intact values. Corresponding increases in the ROM were much smaller:
115%, 184%, and 425% respectively. Direct extrapolation of the in vitro
experimental findings to the clinical situation, as always, should be done with
care. Our findings, however, suggest that the ROM, as measured from functional
radiographs of a traumatized patient, may underestimate the true injury to the
spinal column.
PMID- 9765044
TI - Chronic recurrent multifocal osteomyelitis causing spinal cord compression.
AB - Chronic recurrent multifocal osteomyelitis (CRMO) is a very rare condition of
unknown etiology and most commonly occurs during childhood or adolescence. The
purpose of this paper is to present a case of CRMO in a vertebral location with
severe kyphosis, spinal cord compression, and neurological dysfunction requiring
anterior decompression and fusion. After 12 weeks, the patient was physically
able to return to school. At 2-year follow-up, neurological and functional
outcomes are fair. Magnetic resonance imaging shows good restoration of the
sagittal spine alignment despite residual mild kyphosis, and restoration of a
normal sagittal diameter of the spinal canal.
PMID- 9765045
TI - Intraosseous lipomata of adjacent vertebral bodies.
AB - Osseous lipomata of vertebral bodies are rare. We present a very unusual case
where adjacent vertebrae are involved and the plain radiographic and
scintigraphic appearances gave cause for some concern. The findings on plain
films, scintigraphy, computed tomography and magnetic resonance imaging are
discussed.
PMID- 9765046
TI - Three-level thoracic disc herniation: case report and review of the literature
(P. G. Korovessis et al., ESJ 1997, Vol. 6, p. 74-76)
PMID- 9765047
TI - Spectral analysis methods for neurological signals.
AB - This paper reviews some novel spectral analysis techniques that are useful for
neurological signals in general and EEG signals in particular. First, some
drawbacks and limitations of the commonly used Fast Fourier transforms (FFTs) are
presented, and then alternative algorithms are outlined. An auto-regressive (AR)
modeling based spectral estimation procedure is presented to overcome the
problems of lower resolution and 'leakage' effects inherent in the FFT algorithm.
For signals which are transient in nature or rapidly time-varying, two
alternative algorithms are presented. The first is an adaptive AR parameter
estimation algorithm and the second is a wavelet based time-frequency
representation algorithm. Finally, a Spectral Distance measure and the Itakura
distance measure are presented to quantify the differences between the spectra of
two signals in a succinct manner. The application and performance of all the
algorithms is illustrated using electroencephalograms (EEGs) recorded in animals
during hypoxic asphyxic injury to brain.
PMID- 9765048
TI - The Fourier analysis of biological transients.
AB - With modern computing technology the digital implementation of the Fourier
transform is widely available, mostly in the form of the fast Fourier transform
(FFT). Although the FFT has become almost synonymous with the Fourier transform,
it is a fast numerical technique for computing the discrete Fourier transform
(DFT) of a finite sequence of sampled data. The DFT is not directly equivalent to
the continuous Fourier transform of the underlying biological signal, which
becomes important when analyzing biological transients. Although this distinction
is well known by some, for many it leads to confusion in how to interpret the FFT
of biological data, and in how to precondition data so as to yield a more
accurate Fourier transform using the FFT. We review here the fundamentals of
Fourier analysis with emphasis on the analysis of transient signals. As an
example of a transient, we consider the human saccade to illustrate the pitfalls
and advantages of various Fourier analyses.
PMID- 9765049
TI - A comparison of fast Fourier transform (FFT) and autoregressive (AR) spectral
estimation techniques for the analysis of tremor data.
AB - This review outlines the theory of spectral estimation techniques based on the
fast Fourier transform (FFT) and autoregressive (AR) model and their application
to the analysis of human tremor data. Two FFT-based spectral estimation
techniques are presented, the Blackman-Tukey and periodogram methods. Factors
that influence the quality of spectral estimates are discussed including the
choice of windowing function. The theory of parametric modelling is introduced
and AR modelling identified as the technique best suited to the analysis of
tremor data. The processes of parameter estimation and model order selection are
described. The theory of AR spectral estimation is outlined and differences
between the AR and FFT-based spectral estimates are summarised. A brief guide to
the implementation of FFT-based and AR spectral estimation techniques is given
concentrating on data analysis packages that require little or no programming
expertise. This review concludes that the AR modelling approach can produce
tremor spectra that are superior to those from FFT-based methods for short data
sequences. Although the spectral estimates are improved, the benefits of AR
modelling for providing information about the physiological mechanisms of tremor
generation are not yet clear.
PMID- 9765050
TI - Nonlinear dynamic systems evaluation of rhythmic' eye movements (optokinetic
nystagmus).
AB - The last decade has seen a surge in the study of nonlinear dynamical behavior in
physiologic systems. In this paper, some of the computational techniques most
commonly used to investigate the nonlinear dynamics of these systems are
described. Applications to eye movement analysis are included, including the
validation of a mathematical model of optokinetic nystagmus (OKN) eye movements.
OKN appears to have some nonlinear and deterministic component, along with
significant randomness. Fast phase starting and ending points are somewhat
predictable (deterministic), while so-called 'exceptional events' analysis shows
that they also have a large random component. Surrogate data methods suggest that
the population of slow and fast phases in OKN is more important than any specific
relationship between adjacent slow and fast phases. Analysis of a statistical
model for fast phase intervals indicates that the model data are slightly more
random than the actual OKN.
PMID- 9765051
TI - Identification of patterns of neuronal connectivity--partial spectra, partial
coherence, and neuronal interactions.
AB - The cross-correlation histogram has provided the primary tool for inferring the
structure of common inputs to pairs of neurones. While this technique has
produced useful results it not clear how it may be extended to complex networks.
In this report we introduce a linear model for point process systems. The finite
Fourier transform of this model leads to a regression type analysis of the
relations between spike trains. An advantage of this approach is that the full
range of techniques for multivariate regression analyses becomes available for
spike train analysis. The two main parameters used for the identification of
neural networks are the coherence and partial coherences. The coherence defines a
bounded measure of association between two spike trains and plays the role of a
squared correlation coefficient defined at each frequency lambda. The partial
coherences, analogous to the partial correlations of multiple regression
analysis, allow an assessment of how any number of putative input processes may
influence the relation between any two output processes. In many cases analytic
solutions may be found for coherences and partial coherences for simple neural
networks, and in combination with simulations may be used to test hypotheses
concerning proposed networks inferred from spike train analyses.
PMID- 9765052
TI - On the optimal control of behaviour: a stochastic perspective.
AB - Evolution is a closed stochastic optimisation process driven by the interaction
between behaviour and environment towards local maxima in fitness. It is inferred
that nervous systems are selected to provide optimal control of behaviour (the
'assumption of optimality'), such that for some behaviours, the expectation of
future hazards to survival are minimised. This is illustrated by goal-directed
saccades in which minimising total flight-time of primary and secondary movements
provides a better fit to observations than simply minimising the error of the
primary movement. This optimisation is extended to intra-movement trajectories,
where low-bandwidth (smooth) velocity profiles provide a more satisfactory
description of observations than simple bang-bang control. Since minimum-time
behaviours cannot be controlled by error feedback, it is concluded that the
cerebellum must be executing a real-time unreferenced optimisation process. This
requires explorative as well as exploitative behaviour. Stochastic gradient
descent is discussed as a possible means by which the cerebellum may optimise
behaviour.
PMID- 9765053
TI - Restoration of PEX2 peroxisome assembly defects by overexpression of PMP70.
AB - The mutant Chinese hamster ovary (CHO) cell line Z78/C has defective peroxisome
assembly due to a missense mutation in PEX2, the gene which encodes the 35 kDa
peroxisomal integral membrane protein. In humans, PEX2 mutations are responsible
for complementation group 10 of the human peroxisome biogenesis disorders (PBD),
a genetically heterogeneous group of lethal, autosomal recessive diseases
including the Zellweger syndrome and related phenotypes. To develop additional
cellular models for Zellweger syndrome, we produced a series of new mutant CHO
cell clones in the same complementation group as Z78/C (Z2, Z7, Z22, and Z105).
As expected, expression of human PEX2 restores peroxisomal biogenesis in all of
these clones. Surprisingly, expression of the human 70 kDa peroxisomal membrane
protein (PMP70) also restores peroxisome biogenesis in these same CHO cell
clones. We confirmed this effect of PMP70 expression on peroxisome biogenesis by
determining the subcellular latency of catalase, the immunohistochemical
localization of catalase and the beta-oxidation of very long chain fatty acids
(VLCFA). By contrast, expression of a mutant allele of PMP70 identified in a
patient with Zellweger syndrome did not restore peroxisome biogenesis in the PEX2
deficient CHO cell clones. Our results indicate that overexpression of PMP70
suppresses the phenotype of PEX2 gene mutations. These observations suggest a
functional interaction between PEX2 and PMP70 in the peroxisome membrane.
PMID- 9765054
TI - Spatial differences in gap junction gating in the lens are a consequence of
connexin cleavage.
AB - Gap junctions in the vertebrate lens exhibit spatial differences in pH gating:
those in the cortical fibre cells close upon tissue acidification while those in
the core region do not. It has been speculated that this difference in channel
gating is a consequence of the cleavage of the connexins (Cx) that form the gap
junction channels. We report the construction of a truncation mutant of ovine
Cx50 which mimicks the cleavage in the intact lens. The construct when expressed
in Xenopus oocytes results in the formation of functional channels. Comparison
with full-length Cx50 revealed a significant reduction in the pH-sensitivity of
the truncated form. This is the first evidence linking the non-uniform gating of
gap junction channels in the lens with connexin cleavage. It also reveals how
fibre cells in the core region remain connected despite the acidic environment
caused by elevated lactate levels.
PMID- 9765056
TI - In situ detection of a fungal glycoprotein-elicitor in stem rust-infected
susceptible and resistant wheat using immunogold electron microscopy.
AB - Immunoelectron microscopy (IEM) was used to analyze the compatible and
incompatible host-pathogen interaction between the obligate, biotroph stem rust
(Puccinia graminis f.sp. tritici; Pgt) and primary leaves of wheat (Triticum
aestivum L.). The investigation was focused on the subcellular localization of a
fungal elicitor glycoprotein of stem rust (Pgt-elicitor). Uredospores as well as
fungal infection structures of stem rust on wheat leaves were probed with a
specific monoclonal antibody, in order to determine the in situ distribution
pattern of the antigen. Binding to the anti-elicitor antibody was observed over
the cell wall and the germ pore of germinating uredospores. Immunogold staining
was found over the infection structures of stem rust within the wheat leaf tissue
of both the compatible and incompatible plant-pathogen interaction. Distinct cell
wall layers of the intercellular mycelium, of the haustorial mother cells, as
well as of the haustoria were clearly labeled. Gold particles were also detected
over the intercellular space and the extrahaustorial matrix in between the
extrahaustorial membrane and the haustorial cell wall which indicated a release
of elicitor molecules from the fungal cell wall. No labeling was observed over
the host cell cytoplasm of the compatible and incompatible interaction,
respectively. The immunocytochemical detection of elicitor epitopes over the
hyphal cell walls of in vitro grown axenic cultures of P. graminis f.sp. tritici
confirmed the occurrence of elicitor molecules in young hyphal material. Elicitor
molecules were released by the hyphae of axenic cultures of stem rust in vitro.
PMID- 9765055
TI - Phenotypical changes of a human pancreatic adenocarcinoma cell line after
selection on laminin-1/nidogen (LM/Ng) substratum.
AB - A cell line (PaTu 8902LM) exhibiting an altered phenotypic appearance was
selected from a highly dedifferentiated established human pancreatic tumour cell
line (PaTu 8902) by repetitive exposure to laminin-1/nidogen substratum and
subsequent selection for adherent cells. Polymerase chain reaction analysis for
repetitive DNA indicated that both cell lines are genetically very closely
related. The original PaTu 8902 line consisted of flat cells growing in
monolayers. In contrast, the obtained PaTu 8902LM cells exhibited a spherical
morphology and tended to form clusters. Immunofluorescence analysis using
antibodies against apical and basolateral marker enzymes indicated that the PaTu
8902LM cells were polarized, arranging their apical surfaces around central
lumenal structures when growing in clusters. In addition, the selected PaTu
8902LM cell line exhibited altered levels of a number of differentiation marker
enzymes like 5'-nucleotidase, transglutaminase and plasminogen activators. The
different morphological characteristics of both cell lines were maintained even
after injection into nude mice. In xenografts, PaTu 8902LM cells were grouped
around lumenal, duct-like structures, whereas the original PaTu 8902 cell line
formed solid tumours composed of undifferentiated cells. Evidence is presented
that the PaTu 8902LM cells are not merely selected from preexisting cells, but
that the exposure of PaTu 8902 cells to laminin-1/nidogen had induced a stable
transdifferentiation towards the phenotype of the epithelial cells lining the
pancreatic secretory ducts. Thus the PaTu 8902LM cells resemble more closely
those cells from which tumours of the pancreas originate in vivo and therefore
might be a useful cell system in future analyses of the biology of pancreatic
tumours which are of increasing incidence and clinical importance.
PMID- 9765057
TI - Preferential localization of exocytotic active zones in the terminals of neurite
emitting chromaffin cells.
AB - Amperometry using 2.5 microm radius carbon fiber electrodes was employed to study
exocytotic catecholamine release from individual cultured bovine chromaffin
cells. The secretory responses to either direct depolarization or nicotinic
receptor stimulation were focal in nature in both round and neurite-emitting
cells. In contrast to the random distribution of active sites found in round
cells, bipolar and tripolar chromaffin cells had responsive zones preferentially
located at neurite terminals as indicated by the lower probability of finding
"silent" electrode positions and an increased nicotinic-receptor responsiveness
when compared with the cell body. In agreement with these data we have observed a
preferential deposition of dopamine-beta-hydroxylase into the neurite terminal
plasmalemma after stimulation of intact cells. These observations might be of
interest since the differences in the distribution of secretory "spots" between
round and neurite-emitting chromaffin cells could be used to study the molecular
factors determining active site localization.
PMID- 9765058
TI - Characterization of glial filament-cytoskeletal interactions in human
astrocytomas: an immuno-ultrastructural analysis.
AB - The role that glial filaments play in cells and tumors of glial origin is not
well understood. We therefore undertook the present study to determine the
relationships between glial and vimentin intermediate filaments (IFs), actin
microfilaments, and CD44, a cell surface glycoprotein important in cell migration
and invasion, in human astrocytoma cells. Three astrocytoma cell lines, U343 MG-A
(U343), U251 MG (U251), and antisense GFAP-transfected U251 (asU251) were studied
using immunofluorescence confocal and immunoelectron microscopy. Furthermore, we
studied the phenotypic behaviour of these astrocytoma cell lines by analyzing
their migration through Matrigel in vitro. U343 astrocytoma cells had the highest
expression levels of glial fibrillary acidic protein (GFAP), whereas asU251 had
virtually no expression of GFAP. Parental U251 cells had intermediate expression
levels of GFAP. The elimination of GFAP expression in as U251 cells was
accompanied by a marked increase in vimentin, actin microfilaments and CD44
levels. Gold labeling density counts of cytoskeletal and cell surface elements
demonstrated that the differences between GFAP, actin, CD44 and vimentin levels
in the different astrocytoma cell lines were statistically significant (p <
0.05). Results from the in vitro invasion assay revealed that U343 cells
demonstrated the least invasive potential, whereas asU251 astrocytoma cells
demonstrated the most. Our results show that elimination of GFAP expression by
antisense leads to marked alterations in cell morphology and phenotypic
behaviour. These data imply that GFAP may be linked spatially and functionally to
cytoskeletal elements which may be altered when this IF is deleted in
astrocytomas.
PMID- 9765059
TI - Subcellular localization and possible function of actin, tropomyosin and actin
related protein 3 (Arp3) in the fission yeast Schizosaccharomyces pombe.
AB - We investigated subcellular localizations and interactions of actin and two actin
cytoskeleton-related proteins, Cdc8 tropomyosin and actin-related protein 3,
Arp3, in the fission yeast Schizosaccharomyces pombe, using specific antibodies
and by gene disruption. Actin was localized to the medial microfilamentous ring
in the region of the septum during cytokinesis and to cortical patches by
immunoelectron microscopy. F-actin cables were detected throughout the cell cycle
by fluorescent staining with Bodipy-phallacidin. Cables were often linked to the
patches and to the medial ring during its formation. Tropomyosin was localized to
the medial ring and the cables. It was also distributed in the cell as patches,
although co-localization with F-actin was not frequent. In cdc8ts mutant cells, F
actin cables were not observed although the F-actin patches were detected and
cell polarity was maintained. These observations suggest that the F-actin cables
may be involved in the formation of the medial ring, and that tropomyosin plays
an important role in organizing both the ring and the cable, but is not involved
in the F-actin patch formation or maintenance of cell polarity. Binding of Arp3
to actin was revealed by immunoprecipitation as well as by DNase I column
chromatography. Arp3 seemed to form a complex with several proteins in the cell
extracts, as previously reported for other organisms. Contrary to a previous
report (McCollum et al., EMBO J. 15, 6438-6446, 1996), Arp3 was found to be
concentrated in the medial region from early anaphase to late cytokinesis.
Following arp3 gene disruption, F-actin patches were delocalized throughout the
cell and cells did not undergo polarized growth, suggesting that Arp3 influences
the proper localization of the actin patches in the cell and thereby controls the
polarized growth of the cell.
PMID- 9765060
TI - Toxicokinetics of soman in cerebrospinal fluid and blood of anaesthetized pigs.
AB - The toxicokinetics of the four stereoisomers of the nerve agent C(+/-)P(+/-)
soman was analysed in cerebrospinal fluid (CSF) and blood in anaesthetized,
spontaneously breathing pigs during a 90-min period after injection of soman. The
pigs were challenged with different intravenous (i.v.) doses of C(+/-)P(+/-)
soman corresponding to 0.75-3.0 LD50 (4.5, 9.0 and 18 microg/kg in a bolus
injection and 0.45 microg/kg per min as a slow infusion). Artificial ventilatory
assistance was given if, after soman intoxication, the respiratory rate decreased
below 19 breaths/min. Blood samples were taken from a femoral artery and CSF
samples from an intrathecal catheter. The concentrations of the soman isomers
were determined by gas chromatography coupled with high resolution mass
spectrometry. All four isomers of soman were detected in both blood and CSF
samples. The relatively non-toxic C(+/-)P(+) isomers disappeared from the blood
stream and CSF within the first minute, whereas the levels of the highly toxic
C(+/-)P(-) isomers could be followed for longer, depending on the dose.
Concurrently with the soman analyses in blood and CSF, cholinesterase (ChE)
activity and cardiopulmonary parameters were measured. C(+/-)P(-) isomers showed
approx. 100% bioavailability in CSF when C(+/-)P(+/-)-soman was given i.v. as a
bolus injection. In contrast, C(+/-)P(-) isomers displayed only 30%
bioavailability in CSF after slow i.v. infusion of soman. The ChE activity in
blood decreased below 20% of baseline in all groups of pigs irrespective of the
soman dose. The effect of soman intoxication on the respiratory rate, however,
seems to be dose-dependent and the reason for ventilatory failure and death.
Artificial ventilation resulted in survival of the pigs for the time-period
studied.
PMID- 9765061
TI - Serum and urinary boron levels in rats after single administration of sodium
tetraborate.
AB - The pharmacokinetics of boron was studied in rats by administering a 1 ml oral
dose of sodium tetraborate solution to several groups of rats (n=20) at eleven
different dose levels ranging from 0 to 0.4 mg/100 g body weight as boron. Twenty
four-hour urine samples were collected after boron administration. After 24 h the
average urinary recovery rate for this element was 99.6+/-7.9. The relationship
between boron dose and excretion was linear (r=0.999) with a regression
coefficient of 0.954. This result suggests that the oral bioavailability (F) of
boron was complete. Another group of rats (n=10) was given a single oral
injection of 2 ml of sodium tetraborate solution containing 0.4 mg of boron/100 g
body wt. The serum decay of boron was followed and found to be monophasic. The
data were interpreted according to a one-compartment open model. The appropriate
pharmacokinetic parameters were estimated as follows: absorption half-life,
t1/2a=0.608+/-0.432 h; elimination half-life, t1/2=4.64+/-1.19 h; volume of
distribution, Vd = 142.0+/-30.2 ml/100 g body wt.; total clearance, Ctot=0.359+/
0.0285 ml/min per 100 g body wt. The maximum boron concentration in serum after
administration (Cmax) was 2.13+/-0.270 mg/l, and the time needed to reach this
maximum concentration (Tmax) was 1.76+/-0.887 h. Our results suggest that orally
administered boric acid is rapidly and completely absorbed from the
gastrointestinal tract into the blood stream. Boric acid in the intravascular
space does not have a strong affinity to serum proteins, and rapidly diffuses to
the extravascular space in proportion to blood flow without massive accumulation
or binding in tissues. The main route of boron excretion from the body is via
glomerular filtration. It may be inferred that there is partial tubular
resorption at low plasma levels. The animal model is proposed as a useful tool to
approach the problem of environmental or industrial exposure to boron or in cases
of accidental acute boron intoxication.
PMID- 9765062
TI - Urinary excretion kinetics of 1-hydroxypyrene following intravenous
administration of binary and ternary mixtures of polycyclic aromatic hydrocarbons
in rat.
AB - The effect of exposure to binary and ternary mixtures of polycyclic aromatic
hydrocarbons (PAHs) on the urinary excretion kinetics of 1-hydroxypyrene (1-OHP)
has been examined. Male Sprague-Dawley rats were administered intravenously 5
micromol/kg of pyrene alone or in combination with 0.5, 5 and 25 micromol/kg of
either naphthalene, benzo(a)pyrene (BaP), or both. Urine samples were collected
at frequent intervals over 48 h. The kinetics of 1-OHP in urine was not altered
by the presence of either naphthalene or BaP in the mixtures, at least from 4 h
post-dosing. Hence, none of the injected mixtures significantly modified the
first-order apparent elimination half-life of 1-OHP in urine obtained for the 12
to 42 h period post injection where mean values ranged between 6.2 and 9.6 h.
However, while the presence of naphthalene or the low BaP dose of 0.5 micromol/kg
in the mixtures did not have a significant effect on the total excretion of 1
OHP, BaP doses of 5 and 25 micromol/kg in the mixtures significantly increased
the amount of 1-OHP excreted in urine. Mean percentages of the pyrene dose
excreted as 1-OHP after injection of pyrene in combination with 0.5, 5 and 25
micromol/kg BaP were respectively increased 1.3, 2.2 and 2.6 times compared to
the value obtained after administration of pyrene alone. The percentages
determined after concomitant administration of pyrene and 0.5, 5 and 25
micromol/kg of BaP plus naphthalene were 1.4, 1.8 and 2.4 times, respectively,
the value obtained after administration of pyrene singly. The observed effect of
BaP (5 or 25 micromol/kg) on 1-OHP total excretion appears to result from BaP
induction of pyrene metabolism. Lack of effect of naphthalene appears to be due
to its weak P450 1A1 enzyme induction capacity. Absence of significant effect of
the low BaP dose in the mixtures (0.5 micromol/kg) suggests that 1-OHP in urine
is useful as a bioindicator of occupational and environmental exposures to PAH
mixtures.
PMID- 9765063
TI - Toxicokinetics of 1,2,4-trimethylbenzene in humans exposed to vapours of white
spirit: comparison with exposure to 1,2,4-trimethylbenzene alone.
AB - This study compares the toxicokinetics of inhaled 1,2,4-trimethylbenzene (124TMB)
in men exposed to white spirit with that previously observed in the same
individuals exposed to 124TMB alone. The appropriateness of using
dimethylhippuric acid (DMHA) metabolites of 124-, 123- and 135TMB in urine as
biomarkers of exposure is also addressed and the kinetics of n-decane, n-undecane
and 123TMB is investigated. The toxicokinetics of 124TMB was studied in nine
male, healthy volunteers exposed to solvent vapours in an exposure chamber for 2
h during a work load of 50 W. The subjects were exposed to 2 ppm (11 mg/m3) of
124TM B during exposure to 300 mg/m3 of white spirit. The 124TMB isomer was
analysed in blood, urine and exhaled air by gas chromatography. The DMHA
metabolites of all three TMB isomers were analysed in urine by high-performance
liquid chromatography. The results were compared with previously published
exposures to 2 and 25 ppm (120 mg/m3) of 124TMB vapour alone. In addition, the
occurrence of acute effects was studied by means of a questionnaire. Irritation
and central nervous system (CNS) symptoms were recorded by ratings on a 100 mm
visual analogue scale. Blood levels of 124TMB and excretion rates of 3,4-DMHA in
urine were markedly elevated both during and after exposure to white spirit
compared to the same exposure level of 124TMB alone. No irritation or CNS effects
were reported in the questionnaire at any exposure condition. It appears that
components in white spirit interfere with the metabolic elimination of 124TMB.
This should be considered in biological exposure monitoring as well as in risk
assessment.
PMID- 9765064
TI - Differential alterations in levels of hepatic microsomal cytochrome P450 isozymes
following intracerebroventricular injection of bacterial lipopolysaccharide in
rats.
AB - To investigate the effect of central inflammation due to bacterial infection,
such as meningitis, on the activities of hepatic cytochromes P450 (CYPs), rats
were injected intracerebroventricularly (i.c.v.) with 0.1 microg of bacterial
lipopolysaccharide (LPS). The LPS i.c.v. injection significantly decreased the
total P450 contents (by 30% of the levels of control rats treated with saline
i.c.v.), the contents of CYP1A (48%), 2B (54%), 2C11 (37%) and 3A (40%) and
related drug metabolizing activities, 7-ethoxycoumarin O-deethylation (36%),
imipramine N-demethylation (41%) and erythromycin N-demethylation (33%) in liver
microsomes 24 h after the treatment. In contrast, intraperitoneal (i.p.)
injection of LPS at the same dose as i.c.v. (0.1 microg) did not significantly
affect the hepatic microsomal contents of total P450 or the content of each
individual CYP isozyme and its activity. CYP2D1 protein and the activity of
imipramine 2-hydroxylase were not significantly decreased by LPS injection
regardless of the route of administration. The inhibitory effects of 0.1 microg
i.c.v. LPS on the activities of these CYPs were almost equal to those of 10
microg i.p. LPS, and 0.01 microg of i.c.v. LPS significantly decreased the
activity of imipramine N-demethylase only. Therefore, the LPS i.c.v. injection
resulted in CYP isozyme-selective inhibition at an ineffective dose when injected
i.p.. It is suggested that a central inflammation, such as meningitis,
differentially decreases the levels of hepatic CYP isozymes. A possible
involvement is discussed of the central nervous system in this down-regulation.
PMID- 9765065
TI - Biomonitoring of aromatic amines V: acetylation and deacetylation in the
metabolic activation of aromatic amines as determined by haemoglobin binding.
AB - Aromatic amines are metabolically activated by N-oxidation of either the amine or
the acetamide as a first step and esterification of the resulting N-hydroxyl
derivatives as a second step. Both pathways may lead to DNA-adducts and
subsequently to DNA lesions and mutations. Since the accumulation of non
acetylated adducts has been associated with tumour initiating properties, the
balance between acetylation and deacetylation may greatly influence the
biological effect. Hydrolysable haemoglobin adducts representing the
bioavailability of N-hydroxylamines and the corresponding nitroso-derivatives
were analysed following oral administration to female Wistar rats of two
arylamine-acetamide couples: 4-aminobiphenyl and 2-aminofluorene, and two
arylamine-acetamide-diacetamide triples: benzidine and 3,3'-dichlorobenzidine.
The results show that the monoacetamides are readily deacetylated in vivo whereas
the diacetamides are not. A dynamic equilibrium is indicated to exist between
acetylation and deacetylation, which depends on substrate specificity, and the
role of deacetylation is emphasised. In addition, acetylation polymorphism was
studied with 4-chloroaniline and 3,3'-dichlorobenzidine in slow acetylating A/J
and rapid acetylating C57BL/6J mice. The slow acetylator genotype was associated
with significantly higher haemoglobin-adduct levels for both arylamines. The
results provide additional support for the use of haemoglobin adducts in
biomonitoring as a dosimeter for the biologically active dose of
arylamines/arylacetamides. Moreover, biomonitoring of haemoglobin adducts may
provide information about an individual's susceptibility to the toxic and
carcinogenic effects of these chemicals.
PMID- 9765066
TI - Correlation of 32P-postlabelling-detection of DNA adducts in mouse skin in vivo
with the polycyclic aromatic compound content and mutagenicity in Salmonella
typhimurium of a range of oil products.
AB - The in vivo genotoxic activities in mouse skin of the dimethyl sulphoxide (DMSO)
extracts of a range of oil products [residual aromatic extract; untreated heavy
paraffinic distillate aromatic extract; mildly refined light naphthenic base oil;
bitumen (vacuum residue); high viscosity index base oil obtained by catalytic
hydrogenation] were evaluated by 32P-postlabelling DNA analysis. The results of
quantitative 32P-postlabelling analyses of epidermal DNA from mice treated with
the DMSO extracts showed linear relationships with the total polycyclic aromatic
compound (PAC) contents, determined by the Institute of Petroleum method IP 346
and also the 3-6 ring PAC contents, measured by on-line liquid-liquid extraction
using flow injection analysis. The 32P-postlabelling data also showed a linear
relationship with the mutagenicity indices of these oil products determined in S.
typhimurium TA98 using the modified Ames Salmonella microsome test. The in vivo
genotoxicity of the DMSO extracts from the oil products was low, judged by 32P
postlabelling analysis of DNA adducts measured in epidermal DNA of treated mouse
skin, and ranging from 2 to 723 attomole/microg DNA per mg oil product. The in
vivo 32P-postlabelling data from this study are consistent with these materials
expressing low genotoxicity in mouse skin in vivo. The DMSO extraction procedure
coupled with 32P-postlabelling DNA analysis is useful for ranking the relative
genotoxic potency in vivo of a wide range of oil products. In general the trend
observed is similar to rankings based on physicochemical measurements of total
PAC contents or 3 6 ring PAC contents of the oil products.
PMID- 9765067
TI - Stereospecificity of the sensory irritation receptor for nonreactive chemicals
illustrated by pinene enantiomers.
AB - To clarify the existence of a receptor protein for sensory irritants in
trigeminal nerve endings, D- [i.e. (+)] and L- [i.e. (-)] enantiomers of alpha-
and beta-pinene as models of nonreactive chemicals were evaluated for their
potency in outbred OF1 and NIH/S mice using ASTM E981-84 bioassay. All pinenes
possess sensory irritation properties and also induced sedation and signs of
anaesthesia but had no pulmonary irritation effects. According to the ratio of
RD50 (i.e. concentration which causes a 50% decrease in respiratory rate,f) and
vapour pressure (Po), all pinenes are nonreactive chemicals. For nonreactive
chemicals, Po and olive oil-gas partition (Loil) can be used to estimate their
potency as sensory irritant. Thus, for enantiomers with identical physicochemical
properties, the estimated RD50 values are the same. In addition, although alpha-
and beta-pinene do not have identical Po and Loil values, their estimated
potencies are quite close. However, the experimental results showed that D
enantiomers of pinenes were the most potent as sensory irritants and a difference
in potency also exists between alpha- and beta-pinene. RD50 for D-enantiomers of
alpha- and beta-pinene were almost equal, 1053 ppm and 1279 ppm in OF1 strain and
1107 ppm and 1419 ppm in NIH/S strain, respectively. Values differed by a factor
of approximately 4 to 5 from L-beta-pinene for which the RD50 was 4663 ppm in OF1
and 5811 ppm in NIH/S mice. RD50 could not be determined for L-alpha-pinene; this
pinene was almost inactive. D-alpha-pinene seems to best fit the receptor because
its experimental RD50 was one-half of the estimated value while for D-beta-pinene
those values were equal. On the contrary, L-beta-pinene was about 3 to 4 times
less potent than estimated. L-alpha-pinene was only slightly active although it
was estimated to be as potent as D-alpha-pinene. The remarkable difference in
potency between L-enantiometers is most likely due to a structural difference
between alpha- and beta-pinene: the more flexible beta-pinene can bend to fit
into the receptor better than the rigid alpha-pinene. The results showed that the
commonly used physicochemical descriptors cannot fully explain the potency of
these chemicals; their three-dimensional structure should also be considered.
Because of the stereospecificity of pinenes, a target site for nonreactive
sensory irritants is most likely a receptor protein containing a chiral
lipophilic pocket.
PMID- 9765068
TI - The toxic mechanism and metabolic effects of atractyloside in precision-cut pig
kidney and liver slices.
AB - The toxic and cellular metabolic effects of atractyloside, a diterpenoid
glycoside, which causes fatal renal and hepatic necrosis in vivo in animals and
humans, have been investigated in tissue slices prepared from male domestic pig
kidney and liver. Precision-cut slices (200 microm thick) were incubated with
atractyloside at concentrations of 200 microM, 500 microM, 1.0 mM and 2.0 mM for
3 h at 37 degrees C and changes in lipid profile and pyruvate-stimulated
gluconeogenesis investigated. Lipid peroxidative changes, reduced glutathione
(GSH) and ATP content, the release of lactate dehydrogenase (LDH), alkaline
phosphatase (ALP), alanine and aspartate aminotransferase (ALT/AST) were also
assessed. After 3 h of incubation, atractyloside caused a significant (P < 0.01)
and concentration-dependent leakage of LDH and ALP from kidney slices. Only LDH
leakage was significantly elevated in liver slices while ALT and AST leakage
showed marginal increase. Atractyloside at concentrations of > or =200 microM
caused a significant increase in lipid peroxidation, but only in liver slices.
However, atractyloside at concentrations of > or =200 microM caused a marked
depletion of GSH and ATP content in both kidney and liver slices. There was a
marked decrease in total and individual phospholipid in kidney but not in liver
slices. However, cholesterol and triacylglycerol levels were not affected by
atractyloside in both kidney and liver slices. Renal and hepatic pyruvate
stimulated gluconeogenesis were significantly (P < 0.05) inhibited at
atractyloside concentrations of > or =500 microM. Accumulation of organic anion p
amino-hippuric acid (PAH) was also inhibited in renal cortical slices at
atractyloside concentrations of > or =500 microM. These results suggest that the
observable in vivo effect of atractyloside can be reproduced in slices and that
basic mechanistic differences exist in the mode of toxicity in liver and kidney
tissues. The data also raise the possibility that the mechanistic basis of
metabolic alterations in these tissues following treatment with atractyloside may
be relevant to target selective toxicity.
PMID- 9765069
TI - Glutamine transaminase K intranephron localization in rats determined by urinary
excretion after treatment with segment-specific nephrotoxicants.
AB - Glutamine transaminase K(GTK) excretion assessed in urine and by kidney histology
was evaluated in rats after single treatment with 1.0 mg/kg i.p. of mercuric
chloride, 100 mg/kg i.p. of hexachloro-1:3-butadiene (both S3, pars recta,
segment-specific nephrotoxicants) and 25 mg/kg s.c. of potassium dichromate (S1
S2, pars convoluta, segment-specific nephrotoxicant). The aim was to correlate
segment-specific injury and enzyme excretion in order to assess, using non-vasive
methods, localization of GTK along the proximal tubule. Mercuric chloride and
hexachloro-1:3-butadiene produced early focal damage in the pars recta (focal
necrosis was shown 10 h after treatment, and diffuse necrosis appeared later at
34 and 24 h after treatment). Changes of the pars convoluta were occasional and
delayed (72 h after treatment for both substances). On the contrary, potassium
dichromate induced damage of the pars convoluta (vacuolar degeneration and focal
necrosis were evident 24 h and 48 h after treatment, respectively), whereas the
pars recta was affected later (focal vacuolar degeneration was observed 72 h
after treatment). Increase urinary GTK excretion was early after treatment with
mercuric chloride and hexachloro-1:3-butadiene (significant increase was observed
within 10 h), with a peak for both substances 24 h after treatment, in agreement
with the necrosis of the pars recta. Potassium dichromate induced a significant
increase of enzyme excretion in urine also 24 h after injection, according to
histological features showing vacuolar degeneration of the pars convoluta; the
peak of excretion was reached 48 h after treatment (delay was due, probably, to
s.c. administration). The results show that GTK increased in urine after
treatment with S3 and S1-S2 specific nephrotoxicants; the combination of
histological examination and urinary enzyme supports the evidence that the enzyme
is distributed along the whole of the proximal tubule.
PMID- 9765070
TI - Reduction of cisplatin toxicity in cultured renal tubular cells by the
bioflavonoid quercetin.
AB - Quercetin (QC), a polyphenolic compound widely distributed in fruits and
vegetables has recently gained interest due to its cisplatin (CP) sensitizing
properties in cancer cells. It is currently unknown, whether quercetin also
increases the susceptibility of the kidneys to cisplatin toxicity. We studied the
effects of various bioflavonoids on CP toxicity in an in vitro model of cultured
tubular epithelial cells (LLC-PK1). Viability of LLC-PK1 cells, as assessed by
lactate dehydrogenase (LDH) release and MTT-test, was affected by CP (100-400
microM) in a time and dose dependent fashion. Pretreatment of cells with QC for 3
h significantly reduced the extent of cell damage. The protective activity of QC
was concentration dependent, starting at 10-25 microM and reaching a plateau
between 50 and 100 microM. Other bioflavonoids (catechin, silibinin, rutin) did
not diminish cellular injury, even at higher concentrations (100-500 microM).
Quercetin itself showed some intrinsic cytotoxicity at concentrations exceeding
75 microM. Our data indicate that quercetin reduces cisplatin toxicity in
cultured tubular epithelial cells. The exact mechanism of protection is unclear,
though scavenging of free oxygen radicals may play an important role.
PMID- 9765071
TI - Reduction of thyroid hormone levels by methylsulfonyl metabolites of
polychlorinated biphenyl congeners in rats.
AB - Male Sprague-Dawley rats received four consecutive intraperitoneal doses of four
kinds of methylsulfonyl (MeSO2) metabolites of polychlorinated biphenyl (PCB)
congeners: 3-MeSO2-2,2',3',4',5,6-hexachlorobiphenyl (3-MeSO2-CB132); 3-MeSO2
2,2',3',4', 5,5'-hexachlorobiphenyl (3-MeSO2-CB141); 3-MeSO2-2,2',4',5,5',6
hexachlorobiphenyl (3-MeSO2-CB149) and 4-MeSO2-2,2',4',5,5',6-hexachlorobiphenyl
(4-MeSO2-CB149). The congeners were major MeSO2-PCBs determined in human milk,
liver and adipose tissue, and the aim was to determine their effect on thyroid
hormone levels. All four tested MeSO2 metabolites (20 micromol/kg once daily for
4 days) reduced serum total thyroxine levels by 22-44% at a much lower dose than
phenobarbital (PB; 431 micromol/kg once daily for 4 days) on days 2, 3, 4 and 7
after the final doses. Total triiodothyronine levels were reduced 37% by
treatment with 4-MeSO2-CB149 at day 7. A 30% increase in thyroid weight was
produced by 3-MeSO2-CB141 treatment. Total cytochrome P450 content was increased
by 3-MeSO2-CB132, 3-MeSO2-CB141 and 3-MeSO2-CB149, but not by 4-MeSO2-CB149.
Thus, it is likely that the 3-MeSO2-hexachlorobiphenyls and 4-MeSO2-CB149 could
influence the thyroid hormone metabolism by different mechanism(s). The results
show that tested 3- and 4-MeSO2 metabolites of PCB congeners reduce thyroid
hormone levels much more than PB in rats. Our finding suggests that the
metabolites may act as endocrine-disrupters.
PMID- 9765072
TI - History and future of endoscopic ultrasonography.
PMID- 9765073
TI - Technical advances and future developments in endoscopic ultrasonography.
PMID- 9765074
TI - Clinical applications of endobronchial ultrasonography in lung diseases.
PMID- 9765075
TI - Intraluminal ultrasonography in urology.
PMID- 9765077
TI - EUS training in the USA.
PMID- 9765076
TI - EUS training in Europe.
PMID- 9765078
TI - Education and training in endoscopic ultrasound in Japan.
PMID- 9765079
TI - EUS instruments for esophageal lesions.
PMID- 9765080
TI - The diagnostic value of transendoscopic miniature ultrasonic probe for esophageal
diseases.
AB - BACKGROUND AND STUDY AIMS: To investigate the value of a transendoscopic
miniature ultrasonic probe (USP) in the diagnosis of esophageal diseases.
PATIENTS AND METHODS: Endoscopic ultrasonography was performed by means of USP in
53 patients with esophageal diseases, including 16 with esophageal leiomyoma, 14
with esophageal carcinoma, seven with achalasia, seven with reflux esophagitis,
six with esophageal polyps and three with esophageal varices. RESULTS: USP
clearly showed all 16 esophageal leiomyomas, whereas, conventional EUS could not
show five small leiomyomas less than 1.0 x 1.0 cm in size. The appearance of
esophageal leiomyoma was that of a hypoechoic mass with a homogeneous inner
echogram arising from the fourth hypoechoic layer. All 14 patients with
esophageal carcinoma underwent full endosonographic T and N staging with USP. In
two cases passage of the malignant stenosis proved to be impossible using
conventional EUS. The accuracy of USP on T staging and N staging was 80% and 30%,
respectively. In the seven achalasia patients USP demonstrated a seven-layer
structure of the esophageal wall, with thickening of the third and fifth layers.
In the seven patients with reflux esophagitis no difference was found for the
ultrasonic image between that with and that without Barrett's epithelium. All of
the esophageal polyps were showed by USP as hypoechoic homogeneous lesion with
indistinct margins. After endoscopic sclerotherapy the ultrasonographic feature
of esophageal varices changed from submucosal multiple anechoic areas to high
echoic areas. CONCLUSION: With refinement, the transendoscopic miniature
ultrasonic probe will play an increasing role in the diagnosis of esophageal
disease.
PMID- 9765081
TI - Diagnosis and staging of esophageal carcinoma by endoscopic ultrasonography.
PMID- 9765082
TI - Modified soft-balloon methods during ultrasonic probe examination for superficial
esophageal cancer.
AB - BACKGROUND AND STUDY AIMS: In ultrasonic probe studies for early-stage esophageal
cancer the original soft-balloon method utilizing a condom had succeeded in
obtaining a clear and reproducible picture by keeping deaerated water in a
condom; however, the condom, which covered the endoscope lens, eliminated the
usual endoscopic sight. Therefore, the authors endeavored to develop a modified
method which enables both normal endoscopic observation and ultrasonic probe
study with only a single insertion of the endoscope. PATIENTS AND METHODS: Thirty
one patients with superficial esophageal cancer were included in this pilot
study. As modifications of the soft-balloon technique, two novel methods of
'wrapping' and 'invagination' were developed. RESULTS: These modifications are
considered to have solved the above-mentioned problem and enable one to acquire
both normal endoscopic photos and ultrasonic probe images during the same
insertion of the endoscope. CONCLUSION: In a pilot study novel modifications
improved the method of ultrasonic probe study for superficial esophageal cancer.
PMID- 9765083
TI - Endoscopic ultrasonography in diagnosis and mucosal resection for early
esophageal cancer.
PMID- 9765084
TI - Endosonographic evaluation of the patient with achalasia.
AB - Using endosonography, esophageal wall thickening is commonly observed in patients
with achalasia. Imaging artifacts with the endosonographic appearance of an
esophageal tumor in some patients with achalasia suggest that endosonographic
images must be interpreted with caution. The endosonographer must be aware of
anatomical peculiarities (dilated, tortuous, or "sigmoid" esophagus) and imaging
techniques (tangential imaging) that may lead to artifactual imaging, and thereby
avoid misinterpretation of results. Failure to recognize such imaging artifacts
may lead to an erroneous diagnosis of pseudoachalasia, thereby subjecting
patients to unnecessary surgery. Future applications of endoscopic
ultrasonography for patients with achalasia may include endosonographically
guided therapy. Prospective analyses of EUS-guided therapy are anticipated.
PMID- 9765085
TI - Indications of endoscopic ultrasound in gastric lesions.
PMID- 9765086
TI - Role of endoscopic ultrasonography for gastric lesions.
PMID- 9765087
TI - Miniprobe or ultrasound endoscope for gastric lesions?
PMID- 9765088
TI - Staging of gastric cancer with endoscopic ultrasonography and endoscopic mucosal
resection.
AB - Since it was found that the gastrointestinal wall is visualized as a five-layered
structure corresponding to the histological layers of the wall, endoscopic
ultrasonography (EUS) has become recognized clinically as the most accurate
method for diagnosing and assessing the local staging of gastric cancer. However,
some problems have remained, including how to differentiate between cancer
invasion and ulcer fibrosis, how to detect microinvasion, and how to recognize
malignant lymph nodes. Using the pattern analysis for depressed-type gastric
cancer, it is usually possible to distinguish between cancer invasion and ulcer
fibrosis, except in cases of microinvasion into ulcer fibrosis or inadequate
scanning. However, the sensitivity of EUS for evaluating metastatic lymph nodes
is still problematic. Endoscopic mucosal resection (EMR) for early gastric cancer
has been widely accepted as a standard treatment in Japan due to its minimal
invasiveness. According to our data, the overall rate of radical resection was
68.3% (168 of 246), and 31.7% of the remaining patients additionally received
laser treatment, surgery, or heater-probe treatment. There were no deaths owing
to gastric cancer. Some lesions in which there was microinvasion of the submucosa
were incorrectly diagnosed by EUS. It may be possible to solve this problem using
three-dimensional EUS (3D-EUS) in the near future.
PMID- 9765089
TI - Endoscopic ultrasonography diagnosis in submucosal tumor of stomach.
PMID- 9765091
TI - Endoscopic ultrasonography for the diagnosis of gastric malignant lymphoma.
PMID- 9765090
TI - Endoscopic ultrasonography in large gastric folds.
AB - Large gastric folds are seen in a great number of benign and malignant
conditions. Diagnosis is a clinical challenge because the etiology may be
extremely varied and standard biopsies are often inconclusive. The gastric wall
is considered thickened at endosonography when it is more than 3.6 mm in width.
Different diseases show different levels of infiltration of the gastric wall.
When abnormalities involve the second layer only, benign conditions can be
considered and standard endoscopic biopsies are often diagnostic. When
abnormalities involve layers two and three, different diseases can be suspected,
including Helicobacter pylori infection and lymphoma; in this case large-particle
biopsy should be considered. When abnormalities involve layer four, malignancy
should be strongly suspected even if standard or large-particle biopsies are
negative. Endosonography, always in combination with fine-needle or guillotine
needle biopsy, should be able to rule out malignancies and to select the most
appropriate treatment for each patient.
PMID- 9765092
TI - Indications for endoscopic ultrasonography in colorectal lesions.
PMID- 9765093
TI - Endoscopic ultrasonography versus probe for diagnosis of depth of infiltration of
colorectal cancer.
PMID- 9765094
TI - Endosonographic diagnosis of colorectal cancer.
PMID- 9765095
TI - Endoscopic ultrasonography staging of superficial-type colorectal neoplasms for
mucosectomy.
PMID- 9765096
TI - Endoscopic ultrasonography in the evaluation of inflammatory bowel disease.
PMID- 9765097
TI - Differential diagnosis of mucin-producing tumors of the pancreas by intraductal
ultrasonography and peroral pancreatoscopy.
AB - BACKGROUND AND STUDY AIMS: Although mucin producing tumors of the pancreas have
been recently recognized as premalignant or malignant neoplasms, their diagnosis
and management have been undetermined as yet. The aim of this study was to
evaluate the capability of intraductal ultrasonography (IDUS) and peroral
pancreatoscopy (PPS) in the differential diagnosis of mucin-producing tumors
compared to that of other diagnostic tools. PATIENTS AND METHODS: From 1986 to
1997, 31 patients with mucin-producing tumors of the pancreas underwent surgery.
RESULTS: Histologically, in patients with adenocarcinoma, papillary tumorous
lesions within the pancreatic ducts were 3 mm or more in maximum height. The
detection rates for such lesions were 29% with US, 21% with CT, 86% with EUS,
100% with IDUS and 83% with PPS. In patients with adenocarcinoma, PPS revealed
taller papillary lesions with redness and/or capillary vessels. Biopsy and
cytology during ERCP and under PPS direct vision had a sensitivity of about 60 %
in the differential diagnosis between malignancy and benign diseases.
CONCLUSIONS: Mucin-producing tumors of the pancreas with papillary tumorous
lesions of 3 mm or more in maximum height should be considered as
adenocarcinomas. The combined use of IDUS and PPS with biopsy and cytology is now
considered the best for the differential diagnosis of mucin-producing tumors of
the pancreas.
PMID- 9765098
TI - Staging of pancreatic carcinoma by endoscopic ultrasonography.
PMID- 9765099
TI - Endoscopic ultrasonography diagnosis of pancreatic cystic disease.
PMID- 9765101
TI - Role of endoscopic ultrasound in the diagnosis of cholestasis.
PMID- 9765100
TI - Diagnosis of chronic pancreatitis by endoscopic ultrasonography.
PMID- 9765102
TI - Ultrasound probes for biliary lesions.
PMID- 9765103
TI - Endoscopic ultrasonography diagnosis of gallbladder lesions.
PMID- 9765104
TI - Staging of ampullary carcinoma by endoscopic ultrasonography.
PMID- 9765105
TI - Staging of bile duct carcinoma by EUS and IDUS.
PMID- 9765107
TI - A means of increasing the use of endoscopic ultrasonography: a newly developed
thin video echoendoscope.
PMID- 9765106
TI - Video echoendoscopy in the United States.
PMID- 9765108
TI - A trial of tissue characterization by endoscopic ultrasonography.
PMID- 9765109
TI - Clinical application of ultrasound 3 D imaging system in lesions of the
gastrointestinal tract.
AB - BACKGROUND AND STUDY AIMS: The usefulness of the ultrasound 3 D imaging system (3
D-EUS) is reported. 3 D-EUS using an ultrasonic probe has been introduced as a
result of the developments in 3 D-EUS (EU-IP) by Olympus. The 3 D-EUS image was
reconstructed by composing the radial and linear images produced by 40 slices of
radial image, which were obtained by spiral scanning of the ultrasonic probe in
the sheath. This system also allowed numerous functions, such as multifreeze,
high-resolution images, measurement etc. for a definitive diagnosis. RESULTS: In
the past three years, 190 lesions of the gastrointestinal tract were examined by
3 D-EUS. The rate of correct approach to the lesions was 89% (overall). The most
inappropriate approach was a result of the oblique probe approach, or lesions
sited in difficult positions. The radial, linear and 3 D images were generally
good. Pulsation, deep attenuation and small lesions caused the worst images. Most
small lesions were imaged thoroughly with radial imaging and so no significant
changes can be seen with 3 D images. High-resolution images were more precise and
finer than with plain EUS. CONCLUSIONS: 3 D-EUS contributed more useful and finer
images for the EUS examinations. Gastrointestinal lesions are generally well
displayed and recognizable. There are still a few problems to be solved for
proper imaging, but there should be positive advances in diagnostic ability with
the development of this system.
PMID- 9765110
TI - The use of color Doppler EUS in gastrointestinal diseases.
PMID- 9765111
TI - EUS-guided treatment with microwaves and HIFU.
PMID- 9765112
TI - Indications for EUS-directed FNA.
AB - EUS/FNA is an extremely precise method for sampling lesions surrounding the
gastrointestinal tract. As experience widens, so do the indications for its use.
However, as endoscopists explore ways to use this technique to improve patient
care, a basic premise should be kept in mind: the information obtained should
have the potential to affect patient management. There will undoubtedly be
refinements in the application of EUS/FNA, but the future looks very promising
indeed.
PMID- 9765113
TI - EUS instruments for FNA.
PMID- 9765114
TI - Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) in the USA.
PMID- 9765115
TI - Endoscopic ultrasound-guided fine-needle biopsy in Europe.
PMID- 9765116
TI - EUS-guided fine aspiration biopsy (FNA)--indications and hazards.
AB - Ultrasound endoscopes with mechanical sector forward scan transducers make it
possible to perform FNA under EUS, and drainage by tracing the needle in the
ultrasound pictures by using the same monitor unit as for radial scan ultrasound
endoscopes for EUS diagnosis. It is important to diagnose the lesions from the
histological findings; however, there remain some problems about false negatives,
histological diagnosis from very tiny materials, and the risk of disseminating
the malignant cells by the procedure.
PMID- 9765117
TI - Clinical impact of high-frequency ultrasound probe sonography during diagnostic
endoscopy--a prospective study.
PMID- 9765118
TI - Clinical implications of catheter probe-assisted endoluminal ultrasonography.
PMID- 9765119
TI - Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for the diagnosis
of digestive diseases.
PMID- 9765120
TI - Preoperative endoscopic ultrasonography in decision making and management for
pancreatic endocrine tumors: a 6-year experience.
PMID- 9765121
TI - Optoelectronic monitoring of individual whisker movements in rats.
AB - We describe two systems for the real-time recording and display of individual
vibrissa movements in head-fixed rats. Both systems utilize high-speed, linear
image sensors, each composed of an array of light sensitive elements (CCDs).
Uniform illumination of the array generates a constant baseline voltage in each
element. The shadow produced by the movement of a whisker interposed between the
light source and the sensors produces a voltage shift in a subset of elements.
The successive position of the shift is linearly related to the momentary whisker
position. Associated software/hardware scans the array at regular intervals to
identify the successive positions of voltages above a preset threshold and
outputs the data to a microprocessor for computation of the whisker movement
trajectory. In both systems, movements of a single whisker may be monitored 'on
line' with high spatial and temporal resolution; in one case with, in the other
without the presence of neighboring whiskers. Optoelectronic monitoring
facilitates rapid and efficient (computer-assisted) acquisition and analysis of
data on rodent whisking behavior.
PMID- 9765122
TI - Reduction of background autofluorescence in brain sections following immersion in
sodium borohydride.
AB - Autofluorescence of aldehyde-fixed neural tissue often obscures perikaria and
fine processes labeled with fluorescent anterograde or retrograde tracers. In
particular, this autofluorescence hinders the detectability of fine axonal
projections labeled with the convenient anterograde tracer, tetramethylrhodamine
dextranamine. Background fluorescence was notably reduced by immersion of free
floating brain tissue sections in a solution of sodium borohydride (NaBH4, 0.1%),
a chemical which is known to neutralize Schiffs bases through reduction of amine
aldehyde compounds into non-fluorescent salts. The reversible and renewable
immersion technique was most effective in paraformaldehyde-fixed tissue where the
preservation quality was improved such that labeled axons remained detectable for
more than 1 year after initial preparation.
PMID- 9765123
TI - Characterization of [125I-Tyr0]-corticotropin releasing factor (CRF) binding to
the CRF binding protein using a scintillation proximity assay.
AB - We describe the characterization of high affinity [125I-Tyr0]-human CRF binding
to purified recombinant human CRF-binding protein (CRF-BP) using a scintillation
proximity assay (SPA). For this stable nonseparation technique developed in 96
well microtiter plates, biotinylated CRF-BP is captured by streptavidin-coated
SPA beads for the detection of bound [125I-Tyr0]-CRF. Unbound [125I-Tyr0]-CRF
represented little or no signal in the assay. Total binding observed was greater
than 5000 cpm with a nonspecific signal of < 100 cpm determined in the presence
of excess unlabeled human CRF. A comparison of the SPA method with a charcoal
precipitation method confirmed that the biotinylation procedure did not adversely
affect affinity of the CRF-BP for [125I-Tyr0]-CRF. Saturation binding analysis
yielded an apparent equilibrium dissociation constant (Kd) of 208 +/- 5.0 pM (+/-
S.D., n = 3). An inhibition constant (Ki) for unlabeled CRF was calculated to be
0.22 +/- 0.03 nM (+/- S.D., n = 8) and a pharmacological profile for eight CRF
related neuropeptides gave a rank potency similar to previously reported results.
Finally, the assay variability was assessed with intra- and inter-plate
coefficients of variation which were less than 5% each.
PMID- 9765124
TI - Combined methods of retrograde staining, layer-separation and viscoelastic cell
stabilization to isolate retinal ganglion cells in adult rats.
AB - The adult retinal ganglion cells (RGCs) are widely used as a model to study
mechanisms of de- and regeneration within the central nervous system (CNS). All
regions of the CNS including the retina have the common disadvantage of being
composed of heterogeneous populations of cells, many of them like RGCs making
less than 1% of the total population. This disadvantage can be circumvented by
methodologies aimed at purifying specific cell types. Here we describe a method
that combines retrograde labelling with fluorescent dyes and the pull-off
technique. By using either of four different fluorescent dyes to retrogradely
label RGCs, between 55 and 80% of pre-labelled ganglion cells could be identified
with fluorescence microscopy. The pull-off procedure was supplemented by
enhancing the viscosity of the collecting medium with methylhydroxypropyl
cellulose (MHPC). It appeared that 45% of all RGCs could be collected in the
medium containing MHPC as compared to about 19% of RGCs which could be collected
in medium devoid of cellulose. Despite the fact that morphometric measurements
indicated that 60% of the cells collected fulfilled the criteria of being RGCs,
the population obtained was immensely enriched and sufficed to perform a two
dimensional SDS-gel electrophoresis and to determine their protein composition.
The collected RGCs displayed a similar protein pattern as compared to that of the
total retina, indicating that sublayers of the retina were represented in the
probe. The results suggest that combined approaches of in vivo staining and ex
vivo separation within suitable media enables the collection of an enriched
population of cells which can be processed for biochemical analysis, and perhaps
for molecular biology.
PMID- 9765125
TI - Using miniature sensor coils for simultaneous measurement of orientation and
position of small, fast-moving animals.
AB - A system is described that measures, with a sampling frequency of 1 kHz, the
orientation and position of a blowfly (Calliphora vicina) flying in a volume of
0.4 x 0.4 x 0.4 m3. Orientation is measured with a typical accuracy of 0.5
degrees, and position with a typical accuracy of 1 mm. This is accomplished by
producing a time-varying magnetic field with three orthogonal pairs of field
coils, driven sinusoidally at frequencies of 50, 68, and 86 kHz, respectively.
Each pair induces a voltage at the corresponding frequency in each of three
miniature orthogonal sensor coils mounted on the animal. The sensor coils are
connected via thin (12-microm) wires to a set of nine lock-in amplifiers, each
locking to one of the three field frequencies. Two of the pairs of field coils
produce approximately homogeneous magnetic fields, which are necessary for
reconstructing the orientation of the animal. The third pair produces a gradient
field, which is necessary for reconstructing the position of the animal. Both
sensor coils and leads are light enough (0.8-1.6 mg for three sensor coils of 40
80 windings, and 6.7 mg/m for the leads, causing a maximal load of approximately
5.7 mg) not to hinder normal flight of the animal (typical weight 80 mg). In
general, the system can be used for high-speed recordings of head, eye or limb
movements, where a wire connection is possible, but the mechanical load on the
moving parts needs to be very small.
PMID- 9765126
TI - A dicistronic retroviral vector and culture model for analysis of neuron-Schwann
cell interactions.
AB - A dicistronic retroviral gene delivery system and tissue culture model has been
developed for studies of neuron-Schwann cell interactions at the single cell
level. The dicistronic retroviral vector contains a multiple cloning site
followed by the encephalomyocarditis virus internal ribosomal entry site (EMCV
IRES) and a green fluorescent protein gene. This design allows for 5'-cap
dependent translation of any gene of interest and 5'-cap independent translation
of green fluorescent protein (GFP) from a single dicistronic RNA. The culture
model consists of dorsal root ganglia (DRG) explants grown in defined medium.
Under these conditions the Schwann cell population is selectively expanded and
infected by the retroviral vector, allowing for rapid transfer of genes of
interest selectively to a large percentage of Schwann cells in coculture with
neurons. Infected cells are subsequently identified in living cultures by their
expression of GFP. Infected (GFP expressing) Schwann cells in contact with
neurites continued to exhibit: (1) increased mitotic activity, (2) increased
sensitivity to elevate intracellular calcium in response to extracellular
application of ATP, and (3) myelination. This viral construct has the added
advantage that it allows identification of cells expressing transgenes among a
heterogeneous population by fluorescence microscopy, FACS, or flow cytometry.
PMID- 9765127
TI - Simultaneous determination of acetylcholine, choline and physostigmine in
microdialysis samples from rat hippocampus by microbore liquid
chromatography/electrochemistry on peroxidase redox polymer coated electrodes.
AB - Microbore column liquid chromatography with post-column immobilized enzyme
reactor (IMER) and electrochemical detection on redox polymer coated electrodes
was used for detection of acetylcholine (ACh) and choline (Ch) in microdialysis
samples. The sensitivity of the coated electrodes, decreased gradually by about
10%/day, with highest reduction of 30% within the first 16 h of use. A number of
choline derivatives were tested as possible internal standards, of those
acetylethylhomocholine (AEHCh) and butyrylcholine (BCh) were found the most
suitable candidates since they both provided high enzymatic conversion in the
IMER. Physostigmine produced a negative peak, possibly reflecting oxidation of
eseroline--a decarbamoylated product of reversible reaction of physostigmine with
immobilized acetylcholine esterase. The probes, implanted in the ventral
hippocampi of awake rats were perfused at a flow-rate of 1.25 microl/min with
Ringer solution containing 10 microM physostigmine or with artificial
cerebrospinal fluid only. The concentrations of ACh in 10-microl samples at basal
conditions were between 0.9-2.5 nM, whereas in the presence of physostigmine the
ACh levels raised to 41-48 nM. Physostigmine concentration was reduced to 8.8
microM, indicating its in vivo delivery of about 12%. The coefficients of
variation were reduced from 7.4% for external standard method after every sixth
sample to 5.8% and 5.9% for internal standardization with AEHCh and BCh,
respectively. The latter method shortened the total analysis time by about 15%,
thus being especially suitable for continuous long-lasting off-line or on-line
monitoring. Additionally, other endogenous cholines such as butyrylcholine or
synthetic choline derivatives could be detected by the present method.
PMID- 9765128
TI - Stroke assessment: morphometric infarct size versus neurologic deficit.
AB - We presently examine the relation between histologic infarct size and neurologic
deficit as endpoints and seek to clarify their sensitivity in defining stroke
outcome. Neurologic deficits of 76 cats subjected to middle cerebral artery
occlusion were assessed daily and correlated with the corresponding infarct sizes
determined morphometrically after 2 weeks' survival. A five-item neurologic
deficit score included the time elapsed until hemiparesis, and forced circling
resolved (if ever), presence of impaired placing reactions and time elapsed until
able to stand and being alert. We then evaluated the two endpoints' statistical
powers to detect group differences using two sets of comparison groups. The
neurologic deficit score correlated well with infarct size (r = 0.76, p < 0.001)
and each of the individual deficit score components named above, in turn,
correlated with decreasing power with infarct size. Even so, the number of study
subjects required to achieve the same level of statistical significance in
assessing group differences was two-fold greater when using the neurologic
deficit than the infarct size data: Group sizes of eight and five animals were
sufficient for significant infarct size differences while the groups needed be
expanded to 15 and 10 animals to similarly achieve significant neurologic score
differences. Thus, infarct size emerges as a more sensitive measure of stroke
outcome than does the assessment of neurologic deficits.
PMID- 9765129
TI - Luciferase: a sensitive and quantitative probe for blood-brain barrier
disruption.
AB - A novel method for quantitative analysis of blood-brain barrier (BBB) disruption
is described, using luciferase as a probe in a murine model system. Purified
luciferase was delivered to mouse brain by osmotic BBB disruption with hypertonic
mannitol; control animals received an intracarotid inoculation of saline prior to
infusion of luciferase. Delivery of luciferase to brain tissue was then assessed
by enzyme assay of tissue extracts, and by immunohistochemical staining.
Luciferase activity in the brain of mannitol-treated animals was found to be
significantly elevated (approx. sevenfold), when compared to activity in control
(saline-treated) mice. This finding was confirmed by quantitative
immunohistochemical staining of tissue sections, using a luciferase-specific
antibody. These studies showed that there was an eight-fold elevation in the
level of extravascular luciferase particles within the brain of mannitol-treated
animals, as compared to controls. Taken together these data show that purified
recombinant luciferase can be used as a sensitive probe, with which to study the
integrity of the BBB.
PMID- 9765130
TI - The overall rod performance test in the MPTP-treated-mouse model of Parkinsonism.
AB - We investigated the usefulness of the Overall Rotarod Performance (ORP) test for
evaluating overall locomotory ability in the 1-methyl-4-phenyl-1,2,3,6
tetrahydropyridine (MPTP)-injected-mouse model of Parkinson's disease (PD). For
this procedure, the mice are pretrained on the rotarod and then tested at a
series of increasing speeds, recording the time that the animal remains on the
rod at each speed; the overall rod performance (ORP) of each animal is then
calculated as the area under the curve in a plot of time-on-the-rod against
rotation speed. At 15-day intervals, C57BL/6 mice were injected (or sham
injected) with MPTP, with ORP testing 7-10 days after each injection. After the
fourth injection (day 45), mice in the treated group showed clearly lower ORP
than mice in the control group (70-90% reduction in ORP), and were thus
considered effectively lesioned. Subsequently, we investigated the short-term
effects of apomorphine and L-DOPA on ORP in MPTP-treated mice. Apomorphine (at
0.5 or 2.5 mg/kg) had no significant effect, while L-DOPA (at 80 but not at 40
mg/kg) caused almost complete short-term recovery of pretreatment ORP. By about
100 days after the last MPTP injection, MPTP-treated mice showed partial long
term recovery of ORP; at this stage the mice were killed for tyrosine hydroxylase
(TH) immunohistochemistry studies. TH immunoreactivity in the striatum showed a
strong positive correlation with ORP as tested on day 100. We conclude that the
ORP test is useful for evaluating motor deficit in MPTP-treated mice, and the
effects of subsequent treatments.
PMID- 9765131
TI - A simple, low-cost and fast Peltier thermoregulation set-up for
electrophysiology.
AB - Most of the parameters recorded in electrophysiology are strongly temperature
dependent. In order to control temperature fluctuations we have built a system
that ensures an accurate thermoregulation of the recording chamber. Temperature
of physiological preparations can be changed relatively quickly (about 8 degrees
C/min) and with a good accuracy (+/- 0.5 degrees C) without inducing thermal
oscillations. Contrary to other thermoregulating devices, the temperature
regulation is not carried out through the perfused medium but directly at the
bottom of the chamber where a 3-cm2 Peltier element has been placed. The element
is driven by a dedicated electronic device which controls the amount and the
direction of the current flowing across the Peltier thermocouple. All
construction details and the appropriate electrical circuits are provided. Using
this home-made device, the steady-state chamber temperature could be precisely
monitored with a resolution of +/- 0.1 degrees C in a range of 0-40 degrees C.
This set-up was tested in experiments designed to evaluate the temperature
dependence of synaptic transmission in the Torpedo nerve electroplate synapses
and of calcium currents recorded from isolated nerve cells. This low-cost method
is suitable for a wide range of applications.
PMID- 9765132
TI - Estimating stimulus response latency.
AB - Stimulus response latency is the delay in the onset of stimulus-evoked neuronal
activity. We develop maximum likelihood and least squares estimators of stimulus
response latency and present a comparison of the performance of these methods
with estimators commonly used in the neuroscience literature. The formal
statistical change-point estimation problem is nontrivial due to the inclusion of
a 'nuisance parameter', the end of stationarity in the stimulus-evoked activity.
Our results suggest that the automation of the estimation of stimulus response
latency will benefit from the use of the maximum likelihood estimator.
PMID- 9765133
TI - Disorders of the hallux sesamoid complex: MR features.
AB - Numerous painful conditions can affect the first metatarsophalangeal-sesamoid
joint complex. Symptoms can be of sudden or insidious onset, and be of acute or
chronic duration. Although conventional radiography is recognized as the initial
diagnostic procedure for these symptoms, there is often a need to proceed to MR
imaging. MR imaging is sensitive and can be utilized in the investigation of the
hallux sesamoid complex to differentiate soft tissue from osseous pathology.
Synovitis, tendonitis, and bursitis can be distinguished from bony abnormalities
such as sesamoid fracture, avascular necrosis, and osteomyelitis. An
understanding of MR imaging features and techniques will result in the highest
diagnostic yield. Early and accurate diagnosis of sesamoid complex disorders can
guide the physician to the appropriate clinical management and prevent
potentially harmful longstanding joint dysfunction.
PMID- 9765134
TI - MR imaging of the major nerves about the elbow: cadaveric study examining the
effect of flexion and extension of the elbow and pronation and supination of the
forearm.
AB - Magnetic resonance (MR) imaging provides useful information in the evaluation of
peripheral nerves. Recent advances in MR imaging allow for detailed depiction of
the soft tissue structures of the elbow joint. Three major nerves are present
about the elbow. Six cadaveric elbows were imaged to depict the normal anatomy of
these nerves and to determine the best plane and position of the elbow for
optimal visualization of each nerve. Axial images of the elbow in full extension
with the forearm in supination allow identification of all major nerves. Axial
images with the elbow in full flexion allow accurate assessment of the cubital
tunnel and the ulnar nerve. Axial images of the elbow in full extension with the
forearm in pronation are helpful for assessment of the median and radial nerves
in the forearm.
PMID- 9765135
TI - MR imaging of symptomatic osteochondromas with pathological correlation.
AB - OBJECTIVE: To demonstrate the value of MR imaging in the diagnosis and
differentiation of the various symptomatic complications of osteochondromas,
providing pathological correlation with emphasis on the usefulness of MR imaging
as a single imaging modality in these patients. DESIGN: We retrospectively
reviewed all MR examinations of clinically symptomatic osteochondromas (30
patients) performed at our institution between March 1990 and October 1997.
PATIENTS: Thirty patients had clinically symptomatic osteochondromas during the
study period. Twenty patients were male and 10 were female. There were five cases
of multiple osteochondromatosis. Pathological correlation was available in 24
patients. RESULTS AND CONCLUSION: Symptomatic complications included fracture
(7%), osseous deformity limiting range of motion (23%), vascular injury (7%),
neurological compromise (10%), bursa formation (27%) and malignant transformation
(27%). MR imaging was able to diagnose or suggest the etiology for the clinical
symptomatology in all cases, demonstrating that it is an ideal imaging modality
in the diagnostic evaluation of symptomatic complications of osteochondromas and
often avoids the need for further imaging.
PMID- 9765136
TI - Internal derangement of the knee after ipsilateral femoral shaft fracture: MR
imaging findings.
AB - OBJECTIVE: This study uses magnetic resonance (MR) imaging to delineate the types
and frequencies of injuries seen in the knee after ipsilateral femoral shaft
fracture. We also compare the results of the orthopedic knee examination with the
MR findings. DESIGN AND PATIENTS: MR imaging of the ipsilateral knee was
performed on 34 patients with closed femoral shaft fractures. Indications for
knee MR imaging included knee pain at the time of fracture, soft tissue swelling
or an effusion of the knee, or a positive knee examination under anesthesia. The
patients had a mean age of 27 years and all were stabilized with intramedullary
nails. Imaging was performed a mean time of 2.5 days after surgery. All patients
had knee examinations done under anesthesia, and the MR results were compiled and
compared with the clinical examinations. RESULTS: Ninety-seven percent of
patients demonstrated knee effusions. Twenty-seven percent of patients
demonstrated meniscal tears, with the posterior horn of the medial meniscus most
frequently torn. The medial collateral ligament was the most frequent site of
ligamentous injury (38%) followed by the posterior cruciate ligament (21%). Fifty
percent of patients had injuries of the extensor mechanism. Bone bruises were
noted in 32% of patients. Articular cartilage injuries were confined to the
patella in four cases. One occult tibial plateau fracture and one meniscocapsular
separation were seen. CONCLUSIONS: There is a common incidence of both
ligamentous and meniscal injury to the knee after ipsilateral femoral shaft
fracture. MR imaging can be useful in assessing the extent of injury, and may
reveal findings unsuspected after clinical examination of the knee.
PMID- 9765137
TI - Tarsal navicular relations in club foot: is there a role for magnetic resonance
imaging?
AB - OBJECTIVE: To correlate radiographic and MR appearances with surgical findings to
determine the accuracy of these modalities in demonstrating tarsal navicular (TN)
relations in order to select the appropriate surgical intervention. DESIGN AND
PATIENTS: Fourteen consecutive patients with 19 club feet had anteroposterior and
lateral radiographs and magnetic resonance (MR) imaging performed. Blinded
retrospective interpretation of these studies was correlated with surgical
findings. Movement artifact was responsible for initial non-diagnostic MR scans
in 3 out of 19 feet. RESULTS: Plain radiographs and MR imaging had sensitivities
of 79% and 84% respectively for TN subluxation, while both modalities had 100%
positive predictive value for TN subluxation. Each modality produced
indeterminate results in cases where subluxation was present at surgery, but in
combination there were no false negatives. CONCLUSION: Radiography confidently
predicted the TN alignment in the majority of cases. MR demonstrated TN
relationships in all cases where radiography was indeterminate. It is proposed
that MR has a potential role to demonstrate TN relationships when radiography is
indeterminate or when there is disparity between the clinical and radiographic
assessment.
PMID- 9765138
TI - Sclerotic variant of lymphangiomatosis of bone: imaging findings at diagnosis and
long-term follow-up.
AB - Lymphangiomatosis is an extremely rare congenital disorder affecting visceral
organs and/or the skeletal system. In bone is is usually characterized by
multiple lytic lesions with a lacelike pattern and sclerotic margins of various
thickness. In this case report we demonstrate the rare sclerotic variant of
lymphangiomatosis. We report the development of predominantly sclerotic lesions
at different sites by serial radiographs with a long-term follow-up, and show the
MRI findings of lymphangiomatosis of the spine.
PMID- 9765139
TI - Bifocal sclerosing osteosarcoma: unusual presentation and course.
AB - Multifocal osteosarcoma is uncommon. Long-term survival of an incompletely
treated case is exceptional. We report an unusual case of bifocal sclerosing
osteosarcoma in a 38-year-old women that involved the left ilium and right
proximal femur. The femoral lesion was resected. The tumor in the left ilium was
not treated. She did not receive chemotherapy and has been free of metastases for
7 years. Recently, growth of the pelvic osteosarcoma has resulted in vascular
compression and edema of the lower extremity. The patient's alkaline phosphatase
has been elevated throughout. The tumor was HMB-45 positive, which has not been
previously reported in osteosarcoma. The pathogenesis of multifocal osteosarcoma
is discussed.
PMID- 9765140
TI - Intraarticular epithelioid sarcoma.
AB - A case of an intraarticular epithelioid sarcoma is presented. The patient was a
35 year old man who presented with a 10 months history of a chronic
monoarthritis. The MRI showed a diffuse lesion involving the synovial membrane of
the knee. There was a marked increased signal on T2 weighted images. Most
epithelioid sarcomas involve the subcutaneous tissues of the hands or feet. This
presentation is unusual and this entity should be considered in the differential
diagnosis of an intraarticular proliferative process.
PMID- 9765141
TI - Rheumatoid nodule of the foot: MRI appearances mimicking an indeterminate soft
tissue mass.
AB - Subcutaneous rheumatoid nodules occur commonly in advanced cases of rheumatoid
arthritis, but only rarely appear in the feet. We present a case of a
subcutaneous rheumatoid nodule arising in the heel pad of a 68-year-old man with
a long history of rheumatoid arthritis, along with a review of the literature.
The appearance of the mass on MRI is illustrated and correlated with the
histologic findings. The MRI appearance of a subcutaneous rheumatoid nodule is
that of a nonspecific ill-defined mass with long T1- and long T2-relaxation
times. A differential diagnosis for similar appearing masses is offered.
PMID- 9765142
TI - Epiphyseal separation of the coracoid process without acromioclavicular
dislocation.
AB - A patient with an epiphyseal separation through the base of the coracoid process
of the shoulder associated with a grade I acromioclavicular sprain is reported.
The epiphyseal separation was not visible on conventional roentgenograms. A CT
scan demonstrated the abnormality. In patients with considerable intractable pain
due to contusion of the shoulder, early use of CT should be considered to
determine whether symptoms are caused by epiphyseal separation of the coracoid
process.
PMID- 9765143
TI - Malignant fibrous histiocytoma associated with a bone infarct in a patient with
hereditary bone dysplasia.
AB - Hereditary bone dysplasia (HBD) is an extremely rare clinicopathological entity
manifested by diaphyseal medullary stenosis and cortical bone thickening
associated with a propensity for fractures affecting the long tubular bone.
Malignant transformation has been reported to occur at an alarming frequency. The
hereditary pattern appears to be autosomal dominant. In this paper we present the
case of a 19-year-old man with hereditary bone dysplasia who was unaware of his
underlying condition until he presented with malignant transformation arising in
an area of bone infarct of the left tibia.
PMID- 9765144
TI - Extragnathic fibromyxoma of bone versus inflammatory myofibroblastic tumor.
PMID- 9765145
TI - The chemistry of water on alumina surfaces: reaction dynamics from first
principles
AB - Aluminas and their surface chemistry play a vital role in many areas of modern
technology. The behavior of adsorbed water is particularly important and poorly
understood. Simulations of hydrated alpha-alumina (0001) surfaces with ab initio
molecular dynamics elucidate many aspects of this problem, especially the complex
dynamics of water dissociation and related surface reactions. At low water
coverage, free energy profiles established that molecularly adsorbed water is
metastable and dissociates readily, even in the absence of defects, by a
kinetically preferred pathway. Observations at higher water coverage revealed
rapid dissociation and unanticipated collective effects, including water
catalyzed dissociation and proton transfer reactions between adsorbed water and
hydroxide. The results provide a consistent interpretation of the measured
coverage dependence of water heats of adsorption, hydroxyl vibrational spectra,
and other experiments.
PMID- 9765146
TI - Past temperatures directly from the greenland ice sheet
AB - A Monte Carlo inverse method has been used on the temperature profiles measured
down through the Greenland Ice Core Project (GRIP) borehole, at the summit of the
Greenland Ice Sheet, and the Dye 3 borehole 865 kilometers farther south. The
result is a 50, 000-year-long temperature history at GRIP and a 7000-year history
at Dye 3. The Last Glacial Maximum, the Climatic Optimum, the Medieval Warmth,
the Little Ice Age, and a warm period at 1930 A.D. are resolved from the GRIP
reconstruction with the amplitudes -23 kelvin, +2.5 kelvin, +1 kelvin, -1 kelvin,
and +0.5 kelvin, respectively. The Dye 3 temperature is similar to the GRIP
history but has an amplitude 1.5 times larger, indicating higher climatic
variability there. The calculated terrestrial heat flow density from the GRIP
inversion is 51.3 milliwatts per square meter.
PMID- 9765147
TI - Direct measurement of femtomoles of osmium and the 187Os/186Os ratio in seawater
AB - Two depth profiles of the osmium concentration and the 187Os/186Os isotopic ratio
in the Indian Ocean showed that the osmium concentration seems to be unaltered by
chemical or biological processes occuring in seawater; accordingly, osmium is
conservative. These data were obtained from an experimental method that
eliminated the problems related to osmium preconcentration. This method led to a
new evaluation of the concentration of osmium in seawater; the mean concentration
of osmium and the 187Os/186Os ratio are equal to 10.86 +/- 0.07 picograms per
kilogram and 8.80 +/- 0.07, respectively. The results suggest the existence of an
organocomplex that dominates the speciation of osmium in seawater.
PMID- 9765148
TI - Experimental demonstration of guiding and bending of electromagnetic waves in a
photonic crystal
AB - The routing and interconnection of optical signals through narrow channels and
around sharp corners are important for large-scale all-optical circuit
applications. A recent computational result suggests that photonic crystals may
offer a novel way of achieving this goal by providing a mechanism for guiding
light that is fundamentally different from traditional index guiding. Waveguiding
in a photonic crystal and near 100 percent transmission of electromagnetic waves
around sharp 90 degree corners were observed experimentally. Bending radii were
made smaller than one wavelength.
PMID- 9765149
TI - Organic carbon fluxes and ecological recovery from the cretaceous-tertiary mass
extinction
AB - Differences between the carbon isotopic values of carbonates secreted by planktic
and benthic organisms did not recover to stable preextinction levels for more
than 3 million years after the Cretaceous-Tertiary mass extinction. These
decreased differences may have resulted from a smaller proportion of marine
biological production sinking to deep water in the postextinction ocean. Under
this hypothesis, marine production may have recovered shortly after the mass
extinction, but the structure of the open-ocean ecosystem did not fully recover
for more than 3 million years.
PMID- 9765150
TI - Climate change record in subsurface temperatures: A global perspective
AB - Analyses of underground temperature measurements from 358 boreholes in eastern
North America, central Europe, southern Africa, and Australia indicate that, in
the 20th century, the average surface temperature of Earth has increased by about
0.5 degreesC and that the 20th century has been the warmest of the past five
centuries. The subsurface temperatures also indicate that Earth's mean surface
temperature has increased by about 1.0 degreesC over the past five centuries. The
geothermal data offer an independent confirmation of the unusual character of
20th-century climate that has emerged from recent multiproxy studies.
PMID- 9765151
TI - Isolation of acidophilic methane-oxidizing bacteria from northern peat wetlands.
AB - Acidic northern wetlands are an important source of methane, one of the gases
that contributes to global warming. Methane oxidation in the surface of these
acidic wetlands can reduce the methane flux to the atmosphere up to 90 percent.
Here the isolation of three methanotrophic microorganisms from three boreal
forest sites is reported. They are moderately acidophilic organisms and have a
soluble methane monooxygenase. In contrast to the known groups of methanotrophs,
16S ribosomal DNA sequence analysis shows that they are affiliated with the
acidophilic heterotrophic bacterium Beijerinckia indica subsp. indica.
PMID- 9765152
TI - Alterations of the PPP2R1B gene in human lung and colon cancer.
AB - The PPP2R1B gene, which encodes the beta isoform of the A subunit of the
serine/threonine protein phosphatase 2A (PP2A), was identified as a putative
human tumor suppressor gene. Sequencing of the PPP2R1B gene, located on human
chromosome 11q22-24, revealed somatic alterations in 15% (5 out of 33) of primary
lung tumors, 6% (4 out of 70) of lung tumor-derived cell lines, and 15% (2 out of
13) of primary colon tumors. One deletion mutation generated a truncated PP2A
Abeta protein that was unable to bind to the catalytic subunit of the PP2A
holoenzyme. The PP2R1B gene product may suppress tumor development through its
role in cell cycle regulation and cellular growth control.
PMID- 9765153
TI - Role of farnesyltransferase in ABA regulation of guard cell anion channels and
plant water loss.
AB - Desiccation of plants during drought can be detrimental to agricultural
production. The phytohormone abscisic acid (ABA) reduces water loss by triggering
stomatal pore closure in leaves, a process requiring ion-channel modulation by
cytoplasmic proteins. Deletion of the Arabidopsis farnesyltransferase gene ERA1
or application of farnesyltransferase inhibitors resulted in ABA hypersensitivity
of guard cell anion-channel activation and of stomatal closing. ERA1 was
expressed in guard cells. Double-mutant analyses of era1 with the ABA-insensitive
mutants abi1 and abi2 showed that era1 suppresses the ABA-insensitive phenotypes.
Moreover, era1 plants exhibited a reduction in transpirational water loss during
drought treatment.
PMID- 9765154
TI - Cell surface trafficking of Fas: a rapid mechanism of p53-mediated apoptosis.
AB - p53 acts as a tumor suppressor by inducing both growth arrest and apoptosis. p53
induced apoptosis can occur without new RNA synthesis through an unknown
mechanism. In human vascular smooth muscle cells, p53 activation transiently
increased surface Fas (CD95) expression by transport from the Golgi complex.
Golgi disruption blocked both p53-induced surface Fas expression and apoptosis.
p53 also induced Fas-FADD binding and transiently sensitized cells to Fas-induced
apoptosis. In contrast, lpr and gld fibroblasts were resistant to p53-induced
apoptosis. Thus, p53 can mediate apoptosis through Fas transport from cytoplasmic
stores.
PMID- 9765155
TI - Bifurcation of lipid and protein kinase signals of PI3Kgamma to the protein
kinases PKB and MAPK.
AB - Phosphoinositide 3-kinases (PI3Ks) activate protein kinase PKB (also termed Akt),
and PI3Kgamma activated by heterotrimeric guanosine triphosphate-binding protein
can stimulate mitogen-activated protein kinase (MAPK). Exchange of a putative
lipid substrate-binding site generated PI3Kgamma proteins with altered or aborted
lipid but retained protein kinase activity. Transiently expressed, PI3Kgamma
hybrids exhibited wortmannin-sensitive activation of MAPK, whereas a
catalytically inactive PI3Kgamma did not. Membrane-targeted PI3Kgamma
constitutively produced phosphatidylinositol 3,4, 3,4,5-trisphosphate and
activated PKB but not MAPK. Moreover, stimulation of MAPK in response to
lysophosphatidic acid was blocked by catalytically inactive PI3Kgamma but not by
hybrid PI3Kgammas. Thus, two major signals emerge from PI3Kgamma:
phosphoinositides that target PKB and protein phosphorylation that activates
MAPK.
PMID- 9765156
TI - Controlling gene expression in living cells through small molecule-RNA
interactions.
AB - Short RNA aptamers that specifically bind to a wide variety of ligands in vitro
can be isolated from randomized pools of RNA. Here it is shown that small
molecule aptamers also bound their ligand in vivo, enabling development of a
method for controlling gene expression in living cells. Insertion of a small
molecule aptamer into the 5' untranslated region of a messenger RNA allowed its
translation to be repressible by ligand addition in vitro as well as in mammalian
cells. The ability of small molecules to control expression of specific genes
could facilitate studies in many areas of biology and medicine.
PMID- 9765157
TI - Transition from moderate to excessive drug intake: change in hedonic set point.
AB - Differential access to cocaine self-administration produced two patterns of drug
intake in rats. With 1 hour of access per session, drug intake remained low and
stable. In contrast, with 6 hours of access, drug intake gradually escalated over
days. After escalation, drug consumption was characterized by an increased early
drug loading and an upward shift in the cocaine dose-response function,
suggesting an increase in hedonic set point. After 1 month of abstinence,
escalation of cocaine intake was reinstated to a higher level than before. These
findings may provide an animal model for studying the development of excessive
drug intake and the basis of addiction.
PMID- 9765159
TI - The teenager with epilepsy. Has special needs.
PMID- 9765158
TI - Puzzling out priorities. Why we must acknowledge that rationing is a political
process.
PMID- 9765160
TI - Dying from heart failure: lessons from palliative care. Many patients would
benefit from palliative care at the end of their lives.
PMID- 9765162
TI - Psychiatry, stigma, and resistance. Psychiatrists need to concentrate on
understanding, not simply compliance.
PMID- 9765161
TI - Smoking and stroke: a causative role. Heavy smokers with hypertension benefit
most from stopping.
PMID- 9765163
TI - Repositioning self regulation. The influence of the GMC may be leaking away.
PMID- 9765164
TI - Should inhaled anticholinergics be added to beta2 agonists for treating acute
childhood and adolescent asthma? A systematic review.
AB - OBJECTIVES: To estimate the therapeutic and adverse effects of addition of
inhaled anticholinergics to beta2 agonists in acute asthma in children and
adolescents. DESIGN: Systematic review of randomised controlled trials of
children and adolescents taking beta2 agonists for acute asthma with or without
the addition of inhaled anticholinergics. MAIN OUTCOME MEASURES: Hospital
admission, pulmonary function tests, number of nebulised treatments, relapse, and
adverse effects. RESULTS: Of 37 identified trials, 10 were relevant and six of
these were of high quality. The addition of a single dose of anticholinergic to
beta2 agonist did not reduce hospital admission (relative risk 0.93, 95%
confidence interval 0.65 to 1.32). However, significant group differences in lung
function supporting the combination treatment were observed 60 minutes
(standardised mean difference -0.57, -0.93 to -0.21) and 120 minutes (-0.53,
0.90 to -0.17) after the dose of anticholinergic. In contrast, the addition of
multiple doses of anticholinergics to beta2 agonists, mainly in children and
adolescents with severe exacerbations, reduced the risk of hospital admission by
30% (relative risk 0.72, 0.53 to 0.99). Eleven (95% confidence interval 5 to 250)
children would need to be treated to avoid one admission. A parallel improvement
in lung function (standardised mean difference -0.66, -0.95 to -0.37) was noted
60 minutes after the last combined inhalation. In the single study where
anticholinergics were systematically added to every beta2 agonist inhalation,
irrespective of asthma severity, no group differences were observed for the few
available outcomes. There was no increase in the amount of nausea, vomiting, or
tremor in patients treated with anticholinergics. CONCLUSIONS: Adding multiple
doses of anticholinergics to beta2 agonists seems safe, improves lung function,
and may avoid hospital admission in 1 of 11 such treated patients. Although
multiple doses should be preferred to single doses of anticholinergics, the
available evidence only supports their use in school aged children and
adolescents with severe asthma exacerbation.
PMID- 9765165
TI - Cold related mortalities and protection against cold in Yakutsk, eastern Siberia:
observation and interview study.
AB - OBJECTIVE: To assess how effectively measures adopted in extreme cold in Yakutsk
control winter mortality. DESIGN: Interviews to assess outdoor clothing and
measure indoor temperatures; regressions of these and of delayed cause-specific
mortalities on temperature. Setting Yakutsk, east Siberia, Russia. SUBJECTS: All
people aged 50-59 and 65-74 years living within 400 km of Yakutsk during 1989-95
and sample of 1002 men and women who agreed to be interviewed. MAIN OUTCOME
MEASURES: Daily mortality from all causes and from ischaemic heart,
cerebrovascular, and respiratory disease. RESULTS: Mean temperature for October
March 1989-95 was -26.6 degreesC. At 10.2 degrees C people wore 3.30 (95%
confidence interval 3.08 to 3.53) layers of clothing outdoors, increasing to 4.39
(4.13 to 4.66; P<0. 0001) layers at -20 degrees C. Thick coats, often of fur,
replaced anoraks as temperature fell to -48.2 degrees C. 82% of people went out
each day when temperatures were 10.2 degrees C to -20 degrees C, but below -20
degrees C the proportion fell steadily to 44% (35% to 53%) at -48.2 degrees C
(P<0.001), and overall shivering outdoors did not increase. Living room
temperature was 17.9 (17.2 to 18.5) degrees C at 10.2 degrees C outdoors, 19.6
(18.8 to 20.4) degrees C at -20 degrees C, and 19.1 (18.6 to 19.6) degrees C at
48.2 degrees C. Mortality from all causes and from ischaemic heart and
respiratory disease was unaffected by the fall in temperature. Mortality from
respiratory disease (daily deaths per million) rose from 4.7 (4.3 to 5.1) to 5.1
(4.4 to 5.7) (P=0.03), but this was offset by a fall in deaths from injury.
CONCLUSIONS: People in Yakutsk wore very warm clothing, and in extremely cold
weather stayed indoors in warm housing, preventing the increases in mortality
seen in winter in milder regions of the world. Only respiratory mortality rose,
perhaps because of breathing cold air.
PMID- 9765166
TI - Severe deep white matter lesions and outcome in elderly patients with major
depressive disorder: follow up study.
AB - OBJECTIVE: To determine the difference in outcome among elderly people with major
depression who do and do not have severe white matter lesions on magnetic
resonance imaging. DESIGN: Follow up study. SETTING: Two psychiatric and two
general hospitals in Melbourne, Australia. SUBJECTS: 60 depressed subjects aged
over 55 referred to hospital psychiatric services with major depressive disorder
meeting American Psychiatric Association (DSM-IIIR) criteria. MAIN OUTCOME
MEASURE: Proportion with good outcome as determined by full recovery from initial
illness and no evidence of depressive relapse or cognitive decline during follow
up among those with and without lesions. RESULTS: Mean (SD) follow up was 31.9
(9.9) months. Survival analysis showed a significant effect of severe lesions on
time to poor outcome (P=0.04), with median survival 136 days in those with severe
lesions compared with 315 days in those without. CONCLUSION: Severe white matter
change on magnetic resonance imaging is associated with poor outcome in elderly
depressed subjects.
PMID- 9765167
TI - Does initial management affect the rate of repetition of deliberate self harm?
cohort study.
PMID- 9765168
TI - Clouding of Surgeons' spectacles
PMID- 9765170
TI - The collins case
PMID- 9765169
TI - Comparison of potency of inhaled beclomethasone and budesonide in New Zealand:
retrospective study of computerised general practice records.
AB - OBJECTIVE: To determine whether inhaled budesonide and beclomethasone are
equipotent in the treatment of asthma in primary care. DESIGN: Retrospective
study of computerised clinical records from 28 general practices in New Zealand.
SUBJECTS: 5930 patients who received 16 725 prescriptions for inhaled budesonide
or beclomethasone from 1 July 1994 to 30 June 1995. SETTING: General practices on
the database of the Royal New Zealand College of General Practitioners Research
Unit. Linked information from secondary care was available for a subset of the
practices. MAIN OUTCOME MEASURE: Mean prescribed daily inhaled corticosteroid
dose. RESULTS: The daily prescribed dose was higher for patients receiving
inhaled budesonide (mean 979 microg) than beclomethasone (mean 635 microg), a
difference of 344 microg (95% confidence interval 313 to 376 microg). This
difference was consistent in all age bands and with different types of inhalation
device. Evidence of systematic prescribing of higher doses of budesonide to
patients with more severe asthma was not found. CONCLUSIONS: In primary care in
New Zealand evidence suggests that budesonide is less potent than beclomethasone.
Consideration of validated, established, and other possible markers of asthma
severity did not support confounding by severity as a reason for the higher
prescribed doses of budesonide. Pending further epidemiological evaluation,
international asthma guidelines may need to be modified on the equivalence of
inhaled corticosteroid doses. Furthermore, the comparative potency of newly
developed inhaled steroids in clinical trials will need to be confirmed in
appropriately designed epidemiological studies based in general practice.
PMID- 9765172
TI - The chair sign
PMID- 9765173
TI - Diving and oxygen.
PMID- 9765174
TI - The second phase of priority setting
PMID- 9765171
TI - The muscular dystrophies.
PMID- 9765176
TI - Academic dress
PMID- 9765175
TI - The importance of theories in health care.
PMID- 9765177
TI - The Swiss heroin trials. Trial is needed comparing decriminalisation of heroin
with existing policy of prohibition.
PMID- 9765178
TI - Recovered memories of childhood abuse. We must tell patients that they were not
to blame.
PMID- 9765179
TI - Mouth care and skin care in palliative medicine.
PMID- 9765180
TI - Number needed to harm should be measured for treatments.
PMID- 9765181
TI - Systematic review of trials comparing antibiotic with placebo for acute cough in
adults. Data do not justify study's conclusions.
PMID- 9765182
TI - Celebrity's death from cancer resulted in increased calls to CancerBACUP.
PMID- 9765183
TI - Sumatriptan is not the only analgesic used inappropriately.
PMID- 9765184
TI - Suicide in patients with stroke. Depression may be caused by symptoms affecting
lower urinary tract.
PMID- 9765185
TI - Early diagnosis of cystic fibrosis can improve children's growth.
PMID- 9765186
TI - Smoking and risk of myocardial infarction. Statistical and biological
interactions should not be confused.
PMID- 9765188
TI - Junior doctors advised on self regulation
PMID- 9765187
TI - James alexander ("Hamish") chalmers
PMID- 9765189
TI - Retraction
PMID- 9765190
TI - German medical editors' uphill struggle
PMID- 9765191
TI - Did MONICA really say that?
PMID- 9765192
TI - Healthcare rationing: no desistance, no completion
PMID- 9765193
TI - Multiple doses of anticholinergics are beneficial in severe, acute childhood
asthma
PMID- 9765194
TI - Warm clothing and housing prevent excess winter mortality
PMID- 9765195
TI - White matter lesions predict outcome in late depression
PMID- 9765196
TI - People who decline psychiatric assessment are more likely to repeat self harm
PMID- 9765197
TI - Inhaled budesonide may be less potent than beclomethasone in primary care
PMID- 9765198
TI - Priority setting reaches its second phase
PMID- 9765199
TI - The complexity of p53 modulation: emerging patterns from divergent signals.
PMID- 9765200
TI - Tumor surveillance via the ARF-p53 pathway.
PMID- 9765201
TI - The HIV-1 Tat cellular coactivator Tat-SF1 is a general transcription elongation
factor.
AB - The human immunodeficiency virus type 1 (HIV-1) Tat protein strongly and
specifically stimulates transcription elongation from the HIV-1 LTR and provides
an important in vitro model system to study this process. Here we use protein
affinity chromatography to identify cellular factors involved in transcription
elongation. A Tat-affinity column bound one transcription factor, Tat-SF1,
efficiently and selectively. Tat-SF1 was identified originally as a Tat-specific
coactivator, but we show it is a general transcription elongation factor. Our
results also reveal the existence of an ATP-inactivatable general elongation
factor (AIEF) required for Tat-SF1 activity and for which Tat can substitute
functionally.
PMID- 9765202
TI - Senescence of human fibroblasts induced by oncogenic Raf.
AB - The oncogenes RAS and RAF came to view as agents of neoplastic transformation.
However, in normal cells, these genes can have effects that run counter to
oncogenic transformation, such as arrest of the cell division cycle, induction of
cell differentiation, and apoptosis. Recent work has demonstrated that RAS
elicits proliferative arrest and senescence in normal mouse and human
fibroblasts. Because the Raf/MEK/MAP kinase signaling cascade is a key effector
of signaling from Ras proteins, we examined the ability of conditionally active
forms of Raf-1 to elicit cell cycle arrest and senescence in human cells.
Activation of Raf-1 in nonimmortalized human lung fibroblasts (IMR-90) led to the
prompt and irreversible arrest of cellular proliferation and the premature onset
of senescence. Concomitant with the onset of cell cycle arrest, we observed the
induction of the cyclin-dependent kinase (CDK) inhibitors p21(Cip1) and
p16(Ink4a). Ablation of p53 and p21(Cip1) expression by use of the E6 oncoprotein
of HPV16 demonstrated that expression of these proteins was not required for Raf
induced cell cycle arrest or senescence. Furthermore, cell cycle arrest and
senescence were elicited in IMR-90 cells by the ectopic expression of p16(Ink4a)
alone. Pharmacological inhibition of the Raf/MEK/MAP kinase cascade prevented Raf
from inducing p16(Ink4a) and also prevented Raf-induced senescence. We conclude
that the kinase cascade initiated by Raf can regulate the expression of
p16(Ink4a) and the proliferative arrest and senescence that follows. Induction of
senescence may provide a defense against neoplastic transformation when the MAP
kinase signaling cascade is inappropriately active.
PMID- 9765203
TI - Premature senescence involving p53 and p16 is activated in response to
constitutive MEK/MAPK mitogenic signaling.
AB - Oncogenic Ras transforms immortal rodent cells to a tumorigenic state, in part,
by constitutively transmitting mitogenic signals through the mitogen-activated
protein kinase (MAPK) cascade. In primary cells, Ras is initially mitogenic but
eventually induces premature senescence involving the p53 and p16(INK4a) tumor
suppressors. Constitutive activation of MEK (a component of the MAPK cascade)
induces both p53 and p16, and is required for Ras-induced senescence of normal
human fibroblasts. Furthermore, activated MEK permanently arrests primary murine
fibroblasts but forces uncontrolled mitogenesis and transformation in cells
lacking either p53 or INK4a. The precisely opposite response of normal and
immortalized cells to constitutive activation of the MAPK cascade implies that
premature senescence acts as a fail-safe mechanism to limit the transforming
potential of excessive Ras mitogenic signaling. Consequently, constitutive MAPK
signaling activates p53 and p16 as tumor suppressors.
PMID- 9765204
TI - Chromatin, TAFs, and a novel multiprotein coactivator are required for
synergistic activation by Sp1 and SREBP-1a in vitro.
AB - The promoter selectivity factor Sp1 often cooperates with other enhancer-binding
proteins to activate transcription. To study the molecular underpinnings of these
regulatory events, we have reconstituted in vitro the synergy observed in vivo
between Sp1 and the sterol-regulated factor SREBP-1a at the low density
lipoprotein receptor (LDLR) promoter. Using a highly purified human transcription
system, we found that chromatin, TAFs, and a novel SREBP-binding coactivator
activity, which includes CBP, are all required to mediate full synergistic
activation by Sp1 and SREBP-1a. The SREBP-binding domain of CBP inhibits
activation by SREBP-1a and Sp1 in a dominant-negative fashion that is both
chromatin- and activator-specific. Whereas recombinant CBP alone is not
sufficient to mediate activation, a human cellular fraction containing CBP can
support high levels of chromatin-dependent synergistic activation. Purification
of this activity to near homogeneity resulted in the identification of a
multiprotein coactivator, including CBP, that selectively binds to the SREBP-1a
activation domain and is capable of mediating high levels of synergistic
activation by SREBP/Sp1 on chromatin templates. The development of a
reconstituted chromatin transcription system has allowed us to isolate a novel
coactivator that is recruited by the SREBP-1a activation domain and that
functions in concert with TFIID to coordinate the action of multiple activators
at complex promoters in the context of chromatin.
PMID- 9765205
TI - Negative control of replication initiation by a novel chromosomal locus
exhibiting exceptional affinity for Escherichia coli DnaA protein.
AB - Replication of the Escherichia coli chromosome is initiated at a unique site,
oriC. Concurrent initiation occurs at all oriC sites present in a cell once, and
only once, per cell cycle. A mechanism to ensure cyclic initiation events was
found operating through the chromosomal site, datA, a 1-kb segment located at
94.7 min on the genetic map that titrates exceptionally large amounts of the
bacterial initiator protein, DnaA. A strain lacking datA grew normally but
exhibited an asynchronous initiation phenotype as a result of extra initiation
events. This mutant phenotype was suppressed by DnaA-titrating plasmids.
Furthermore, mutations in a 9-bp DnaA-binding sequence (the DnaA box) in datA
were enough to induce the mutant phenotype. Thus, datA is a novel chromosomal
element that appears to adjust a balance between free and bound DnaA for a single
initiation event at a fixed time in the bacterial cell cycle. Titration of DnaA
to newly duplicated datA during oriC sequestration, which is mediated by
hemimethylated GATC sequences in oriC and the SeqA protein, would contribute to
prevention of reinitiations when oriC is desequestered.
PMID- 9765206
TI - Yeast telomeres exert a position effect on recombination between internal tracts
of yeast telomeric DNA.
AB - In Saccharomyces cerevisiae, proximity to a telomere affects both transcription
and replication of adjacent DNA. In this study, we show that telomeres also
impose a position effect on mitotic recombination. The rate of recombination
between directly repeated tracts of telomeric C1-3A/TG1-3 DNA was reduced
severely by proximity to a telomere. In contrast, recombination of two control
substrates was not affected by telomere proximity. Thus, unlike position effects
on transcription or replication, inhibition of recombination was sequence
specific. Moreover, the repression of recombination was not under the same
control as transcriptional repression (telomere position effect; TPE), as
mutations in genes essential for TPE did not alleviate telomeric repression of
recombination. The reduction in recombination between C1-3A/TG1-3 tracts near the
telomere was caused by an absence of Rad52p-dependent events as well as a
reduction in Rad1p-dependent events. The sequence-specific repression of
recombination near the telomere was eliminated in cells that overexpressed the
telomere-binding protein Rap1p, a condition that also increased recombination
between C1-3A/TG1-3 tracts at internal positions on the chromosome. We propose
that the specific inhibition between C1-3A/TG1-3 tracts near the telomere occurs
through the action of a telomere-specific end-binding protein that binds to the
single-strand TG1-3 tail generated during the processing of recombination
intermediates. The recombination inhibitor protein may also block recombination
between endogenous telomeres.
PMID- 9765207
TI - Pleiotropic control of glucose and hormone responses by PRL1, a nuclear WD
protein, in Arabidopsis.
AB - The prl1 mutation localized by T-DNA tagging on Arabidopsis chromosome 4-44
confers hypersensitivity to glucose and sucrose. The prl1 mutation results in
transcriptional derepression of glucose responsive genes defining a novel
suppressor function in glucose signaling. The prl1 mutation also augments the
sensitivity of plants to growth hormones including cytokinin, ethylene, abscisic
acid, and auxin; stimulates the accumulation of sugars and starch in leaves; and
inhibits root elongation. PRL1 encodes a regulatory WD protein that interacts
with ATHKAP2, an alpha-importin nuclear import receptor, and is imported into the
nucleus in Arabidopsis. Potential functional conservation of PRL1 homologs found
in other eukaryotes is indicated by nuclear localization of PRL1 in monkey COS-1
cells and selective interaction of PRL1 with a nuclear protein kinase C-betaII
isoenzyme involved in human insulin signaling.
PMID- 9765208
TI - Synapse-specific and neuregulin-induced transcription require an ets site that
binds GABPalpha/GABPbeta.
AB - Localization of acetylcholine receptors (AChRs) to neuromuscular synapses is
mediated by multiple pathways. Agrin, which is the signal for one pathway,
stimulates a redistribution of previously unlocalized AChRs to synaptic sites.
The signal for a second pathway is not known, but this signal stimulates
selective transcription of AChR genes in myofiber nuclei located near the
synaptic site. Neuregulin (NRG) is a good candidate for the extracellular signal
that induces synapse-specific gene expression, since NRG is concentrated at
synaptic sites and activates AChR gene expression in cultured muscle cells.
Previous studies have demonstrated that 181 bp of 5' flanking DNA from the AChR
delta-subunit gene are sufficient to confer synapse-specific transcription in
transgenic mice and NRG responsiveness in cultured muscle cells, but the critical
sequences within this cis-acting regulatory region have not been identified. We
transfected AChR delta-subunit-hGH gene fusions into a muscle cell line, and we
show that a potential binding site for Ets proteins is required for NRG-induced
gene expression. Furthermore, we produced transgenic mice carrying AChR delta
subunit-hGH gene fusions with a mutation in this NRG-response element (NRE), and
we show that this NRE is necessary for synapse-specific transcription in mice.
The NRE binds proteins in myotube nuclear extracts, and nucleotides that are
important for NRG responsiveness are likewise critical for formation of the
protein-DNA complex. This complex contains GABPalpha, an Ets protein, and
GABPbeta, a protein that lacks an Ets domain but dimerizes with GABPalpha,
because formation of the protein-DNA complex is inhibited by antibodies to either
GABPalpha or GABPbeta. These results demonstrate that synapse-specific and NRG
induced gene expression require an Ets-binding site and suggest that
GABPalpha/GABPbeta mediates the transcriptional response of the AChR delta
subunit gene to synaptic signals, including NRG.
PMID- 9765209
TI - Synergistic cooperation of TFE3 and smad proteins in TGF-beta-induced
transcription of the plasminogen activator inhibitor-1 gene.
AB - Members of the TGF-beta superfamily influence a broad range of biological
activities including stimulation of wound healing and inhibition of cell growth.
TGF-beta signals through type I and II receptor serine/ threonine kinases and
induces transcription of many genes including plasminogen activator inhibitor-1
(PAI-1). To identify proteins that participate in TGF-beta-induced gene
expression, we developed a novel retrovirus-mediated expression cloning strategy;
and using this approach, we established that transcription factor microE3 (TFE3)
is involved in TGF-beta-induced activation of the PAI-1 promoter. We showed that
TFE3 binds to an E-box sequence in PE2, a 56-bp promoter fragment of the PAI-1
promoter, and that mutation of this sequence abolishes both TFE3 binding as well
as TGF-beta-dependent activation. TFE3 and Smad3 synergistically activate the PE2
promoter and phosphorylated Smad3 and Smad4 bind to a sequence adjacent to the
TFE3-binding site in this promoter. Binding of both TFE3 and the Smad proteins to
their cognate sequences is indispensable for TGF-beta-inducible activation of the
PE2 promoter. Hence, TFE3 is an important transcription factor in at least one
TGF-beta-activated signal transduction pathway.
PMID- 9765210
TI - Eph signaling is required for segmentation and differentiation of the somites.
AB - Somitogenesis involves the segmentation of the paraxial mesoderm into units along
the anteroposterior axis. Here we show a role for Eph and ephrin signaling in the
patterning of presomitic mesoderm and formation of the somites. Ephrin-A-L1 and
ephrin-B2 are expressed in an iterative manner in the developing somites and
presomitic mesoderm, as is the Eph receptor EphA4. We have examined the role of
these proteins by injection of RNA, encoding dominant negative forms of Eph
receptors and ephrins. Interruption of Eph signaling leads to abnormal somite
boundary formation and reduced or disturbed myoD expression in the myotome.
Disruption of Eph family signaling delays the normal down-regulation of her1 and
Delta D expression in the anterior presomitic mesoderm and disrupts myogenic
differentiation. We suggest that Eph signaling has a key role in the translation
of the patterning of presomitic mesoderm into somites.
PMID- 9765211
TI - Interaction of a nascent RNA structure with RNA polymerase is required for
hairpin-dependent transcriptional pausing but not for transcript release.
AB - Nascent RNA structures may regulate RNA chain elongation either directly through
interaction with RNA polymerase or indirectly by disrupting nascent RNA contacts
with polymerase or DNA. To distinguish these mechanisms we tested whether the
effects of the his leader pause RNA hairpin could be mimicked by pairing of
antisense DNA or RNA oligonucleotides to the nascent transcript. The his pause
hairpin inhibits nucleotide addition when it forms 11 nucleotides from the
transcript 3' end. It also can terminate transcription when base changes extend
its stem to =8 nucleotides from the 3' end. All oligonucleotides that disrupted
the pause hairpin reduced the dwell time of RNA polymerase at the pause site
dramatically, even when they mimicked the 11-nucleotide 3'-proximal RNA spacing
or created a suitably positioned RNA loop. Oligonucleotides that paired =8
nucleotides from the pause RNA 3' end could trigger transcript release, but only
when added to an already paused complex. These results argue that direct
interaction of a nascent RNA hairpin with RNA polymerase delays escape from a
pause, but that indirect effects of a hairpin may trigger transcript release from
a paused complex. Resistance of the paused complex to pyrophosphorolysis and its
reversal by antisense oligonucleotides further suggest that interaction of the
pause hairpin with RNA polymerase disengages the RNA 3' end from the active site.
PMID- 9765214
TI - Electrostatic origin of the catalytic power of enzymes and the role of
preorganized active sites.
PMID- 9765212
TI - The flagellar anti-sigma factor FlgM actively dissociates Salmonella typhimurium
sigma28 RNA polymerase holoenzyme.
AB - The anti-sigma factor FlgM of Salmonella typhimurium inhibits transcription of
class 3 flagellar genes through a direct interaction with the flagellar-specific
sigma factor, sigma28. FlgM is believed to prevent RNA polymerase (RNAP)
holoenzyme formation by sequestering free sigma28. We have analyzed FlgM-mediated
inhibition of sigma28 activity in vitro. FlgM is able to inhibit sigma28 activity
even when sigma28 is first allowed to associate with core RNAP. Surface plasmon
resonance (SPR) was used to evaluate the interaction between FlgM and both
sigma28 and sigma28 holoenzyme (Esigma28). The Kd of the sigma28-FlgM complex is
approximately 2 x 10(-10) M; missense mutations in FlgM that cause a defect in
sigma28 inhibition in vivo increase the Kd of this interaction by 4- to 10-fold.
SPR measurements of Esigma28 dissociation in the presence of FlgM indicate that
FlgM destabilizes Esigma28, presumably via an interaction with the sigma subunit.
Our data provide the first direct evidence of an interaction between FlgM and
Esigma28. We propose that this secondary activity of FlgM, which we term
holoenzyme destabilization, enhances the sensitivity of the cell to changes in
FlgM levels during flagellar biogenesis.
PMID- 9765215
TI - Multitissue circadian expression of rat period homolog (rPer2) mRNA is governed
by the mammalian circadian clock, the suprachiasmatic nucleus in the brain.
AB - The period (per) gene, controlling circadian rhythms in Drosophila, is expressed
throughout the body in a circadian manner. A homolog of Drosophila per was
isolated from rat and designated as rPer2. The rPER2 protein showed 39 and 95%
amino acid identity with mPER1 and mPER2 (mouse homologs of per) proteins,
respectively. A robust circadian fluctuation of rPer2 mRNA expression was
discovered not only in the suprachiasmatic nucleus (SCN) of the hypothalamus but
also in other tissues including eye, brain, heart, lung, spleen, liver, and
kidney. Furthermore, the peripheral circadian expression of rPer2 mRNA was
abolished in SCN-lesioned rats that showed behavioral arrhythmicity. These
findings suggest that the multitissue circadian expression of rPer2 mRNA was
governed by the mammalian brain clock SCN and also suggest that the rPer2 gene
was involved in the circadian rhythm of locomotor behavior in mammals.
PMID- 9765213
TI - Identification of APN2, the Saccharomyces cerevisiae homolog of the major human
AP endonuclease HAP1, and its role in the repair of abasic sites.
AB - Abasic (AP) sites arise in DNA through spontaneous base loss and enzymatic
removal of damaged bases. APN1 encodes the major AP-endonuclease of Saccharomyces
cerevisiae. Human HAP1 (REF1) encodes the major AP endonuclease which, in
addition to its role in DNA repair, functions as a redox regulatory protein. We
identify APN2, the yeast homolog of HAP1 and provide evidence that Apn1 and Apn2
represent alternate pathways for repairing AP sites. The apn1Delta apn2Delta
strain displays a highly elevated level of MMS-induced mutagenesis, which is
dependent on the REV3, REV7, and REV1 genes. Our findings indicate that AP sites
are highly cytotoxic and mutagenic in eukaryotes, and that the REV3, REV7-encoded
DNA polymerase zeta mediates the mutagenic bypass of AP sites.
PMID- 9765216
TI - Biochemical and evolutionary significance of phospholipid methylation.
AB - All nucleated mammalian cells synthesize phosphatidylcholine from choline via the
CDP-choline pathway. Hepatocytes have a second pathway for the synthesis of
phosphatidylcholine, a stepwise methylation of phosphatidylethanolamine,
catalyzed by phosphatidylethanolamine N-methyltransferase and encoded by the
Pempt gene. We report that when Pempt-deficient mice were fed a choline-deficient
diet for 3 days, severe liver pathology occurred apparently due to a lack of
phosphatidylcholine biosynthesis. The hepatic concentration of
phosphatidylcholine decreased by 50% compared with wild type mice on the diet.
The levels of plasma triacylglycerols and cholesterol were decreased by greater
than 90% in the Pempt-deficient mice. We suggest that the Pempt gene has been
maintained during evolution to provide phosphatidylcholine when dietary choline
is insufficient, as might occur during starvation or pregnancy.
PMID- 9765217
TI - Induction of Rb-associated protein (RbAp46) by Wilms' tumor suppressor WT1
mediates growth inhibition.
AB - The Wilms' tumor suppressor gene, wt1, encodes a zinc-finger transcription
factor, WT1, that plays an important role in controlling urogenital development.
Previously, WT1 has been shown to inhibit cell growth and to repress
transcription initiated from the promoters of a number of growth-promoting genes.
However, few physiological target genes that are transcriptionally activated by
WT1 have been established. Using suppression subtractive hybridization polymerase
chain reaction, we isolated a WT1 target gene that is up-regulated about 15-fold
in cells expressing WT1. The gene was identified as retinoblastoma suppressor
(Rb)-associated protein 46 (RbAp46), a nuclear protein that interacts physically
with Rb and is a component of the human mSin3 co-repressor complex. Cells
transfected with RbAp46 cDNA formed fewer colonies than the control cells, and
RbAp46 suppressed the growth rate (by about 2-fold) of transfected cells. In the
developing kidney and gonad, RbAp46 exhibits an expression pattern similar to
that of WT1. We conclude that RbAp46 has strong growth inhibition activity and
may function as an important mediator of WT1's function.
PMID- 9765218
TI - A novel protein containing Cdc10/SWI6 motifs regulates expression of mRNA
encoding catecholamine biosynthesizing enzymes.
AB - Catecholaminergic (dopaminergic, noradrenergic, and adrenergic) transmitter
phenotypes require the cooperative actions of four biosynthetic enzymes: tyrosine
hydroxylase, aromatic L-amino acid decarboxylase, dopamine beta-hydroxylase, and
phenylethanolamine N-methyltransferase. Mechanisms that control expression of
these enzymes in a transmitter phenotype-specific manner, however, are poorly
understood. Here, we provide evidence that overexpression of a novel cdc10/SWI6
motif-containing protein, V-1, elicits the coordinate up-regulation of tyrosine
hydroxylase, aromatic L-amino acid decarboxylase, and dopamine beta-hydroxylase
mRNAs in the neuronal cell line PC12D, and as a result, catecholamine levels are
increased. Furthermore, V-1 is strongly expressed in the cytoplasm of rat
chromaffin cells of adrenal medulla. Thus, V-1 may act as a cytoplasmic
protein/protein adapter and be involved in control of the catecholaminergic
phenotype expression via an intracellular pathway signaling to the nucleus.
PMID- 9765219
TI - A 17-amino acid insert changes UDP-N-acetylhexosamine pyrophosphorylase
specificity from UDP-GalNAc to UDP-GlcNAc.
AB - We previously reported the purification of a UDP-N-acetylhexosamine (UDP-HexNAc)
pyrophosphorylase from pig liver that catalyzed the synthesis of both UDP-GlcNAc
and UDP-GalNAc from UTP and the appropriate HexNAc-1-P (Szumilo, T., Zeng, Y.,
Pastuszak, I., Drake, R., Szumilo, H., and Elbein, A. D. (1996) J. Biol. Chem.
271, 13147-13154). Both sugar nucleotides were synthesized at nearly the same
rate, although the Km for GalNAc-1-P was about 3 times higher than for GlcNAc-1
P. Based on native gels and SDS-polyacrylamide gel electrophoresis, the enzyme
appeared to be a dimer of 120 kDa composed of two subunits of about 57 and 64
kDa. Three peptides sequenced from the 64-kDa protein and two from the 57-kDa
protein showed 100% identity to AGX1, a 57-kDa protein of unknown function from
human sperm. An isoform called AGX2 is identical in sequence to AGX1 except that
it has a 17-amino acid insert near the carboxyl terminus. We expressed the AGX1
and AGX2 genes in Escherichia coli. The protein isolated from the AGX1 clone
comigrated on SDS gels with the liver 57-kDa pyrophosphorylase subunit and was 2
3 times more active with GalNAc-1-P than with GlcNAc-1-P. On the other hand, the
protein from the AGX2 clone migrated with the liver 64-kDa pyrophosphorylase
subunit and had 8-fold better activity with GlcNAc-1-P than with GalNAc-1-P.
These results indicate that insertion of the 17-amino acid peptide modifies the
specificity of the pyrophosphorylase from synthesis of UDP-GalNAc to synthesis of
UDP-GlcNAc.
PMID- 9765220
TI - Hormone-induced translocation of thyroid hormone receptors in living cells
visualized using a receptor green fluorescent protein chimera.
AB - Thyroid hormone nuclear receptors (TRs) are ligand-dependent transcription
factors that regulate growth, differentiation, and development. To understand the
role of the hormone, 3,3', 5-triiodo-L-thyronine (T3), in the nuclear
translocation and targeting of TRs to the regulatory sites in chromatin, we
appended green fluorescent protein (GFP) to the human TR subtype beta1 (TRbeta1).
The fusion of GFP to the amino terminus of TRbeta1 protein did not alter T3
binding or transcriptional activities of the receptor. The subcellular
localization of GFP-TRbeta1 in living cells was visualized by laser-scanning
confocal microscopy. In the presence of T3, the expressed GFP-TRbeta1 was
predominately localized in the nucleus, exhibiting a nuclear/cytoplasmic ratio of
approximately 5.5. No GFP-TRbeta1 was detected in the nucleolus. In the absence
of T3, more GFP-TRbeta1 was present in the cytoplasm, exhibiting a
nuclear/cytoplasmic ratio of approximately 1.5. In these cells, cytoplasmic GFP
TRbeta1 could be induced to enter the nucleus by T3. The T3-induced translocation
was blocked when Lys184-Arg185 in domain D of TRbeta1 was mutated to Ala184
Ala185. Furthermore, the inability of the mutant TR to translocate to the nucleus
correlated with the loss of most of its transcriptional activity. These results
suggest that TR functions may, in part, be regulated by T3-induced nuclear entry.
PMID- 9765221
TI - Purification and properties of a novel chloroplast stromal peptidase. Processing
of polyphenol oxidase and other imported precursors.
AB - Polyphenol oxidases (PPOs) are nuclear-encoded chloroplast proteins that are
targeted to the thylakoid lumen by a bipartite presequence. The N-terminal part
of this sequence is removed by a stromal processing peptidase (SPP), and the
resulting intermediate is translocated across the thylakoid and processed to the
mature protein. A 4800-fold-purified SPP processed a PPO precursor (pPPO) at a
site identical to that occurring in organelle. The in vitro product of SPP action
on pPPO was further processed and translocated by thylakoids. This SPP processed
other precursors but was inactive toward those of light-harvesting chlorophyll
binding proteins. The enzyme appeared to be a metalloendopeptidase, like
previously reported SPPs. However, it differed in substrate specificity, apparent
size, and, most significantly, cleavage site of pPPO. Whereas the processing
sites of lumen proteins determined so far were relatively distant from the
hydrophobic core of the thylakoid targeting domain, pPPO was cleaved immediately
before this domain. Cleavage removed the twin arginine motif characteristic of
thylakoid targeting domains of lumen proteins, which are translocated by the
DeltapH-dependent pathway. The possible significance of these observations to PPO
translocation mechanism is discussed. It is suggested that several SPPs may exist
in chloroplasts with preferences for different subsets of precursors.
PMID- 9765222
TI - The phosphorylation of protein S6 modulates the interaction of the 40 S ribosomal
subunit with the 5'-untranslated region of a dictyostelium pre-spore-specific
mRNA and controls its stability.
AB - AC914 mRNA, a pre-spore-specific mRNA that accumulates only in the post
aggregation stage of development, is transcribed constitutively as shown by
nuclear run-off experiments and by fusing its promoter to the luciferase reporter
gene. The same mRNA disappears quickly from disaggregated cells. If the 5'
untranslated region (5'UTR) of the constitutively expressed Actin 15 mRNA is
substituted for the 5'UTR of AC914 mRNA, this can no longer be destabilized and
accumulates both in growing and disaggregated cells. If the 5'UTR of AC914 mRNA
is substituted for the 5'UTR of Actin 15 mRNA, the latter accumulates only in
aggregated cells. Pactamycin, but not other inhibitors of protein synthesis,
prevents AC914 mRNA from being destabilized in disaggregated cells, suggesting a
role of 40 S subunits in the destabilization. This has been confirmed by using an
in vitro system in which the in vivo stability of different mRNAs is reproduced.
A protein kinase A-dependent phosphorylation of ribosomal protein S6 determines
whether 40 S subunits are capable or not of destabilizing AC914 mRNA in the in
vitro system.
PMID- 9765223
TI - delta-Atracotoxins from australian funnel-web spiders compete with scorpion alpha
toxin binding but differentially modulate alkaloid toxin activation of voltage
gated sodium channels.
AB - delta-Atracotoxins from the venom of Australian funnel-web spiders are a unique
group of peptide toxins that slow sodium current inactivation in a manner similar
to scorpion alpha-toxins. To analyze their interaction with known sodium channel
neurotoxin receptor sites, we studied their effect on [3H]batrachotoxin and 125I
Lqh II (where Lqh is alpha-toxin II from the venom of the scorpion Leiurus
quinquestriatus hebraeus) binding and on alkaloid toxin-stimulated 22Na+ uptake
in rat brain synaptosomes. delta-Atracotoxins significantly increased
[3H]batrachotoxin binding yet decreased maximal batrachotoxin-activated 22Na+
uptake by 70-80%, the latter in marked contrast to the effect of scorpion alpha
toxins. Unlike the inhibition of batrachotoxin-activated 22Na+ uptake, delta
atracotoxins increased veratridine-stimulated 22Na+ uptake by converting
veratridine from a partial to a full agonist, analogous to scorpion alpha-toxins.
Hence, delta-atracotoxins are able to differentiate between the open state of the
sodium channel stabilized by batrachotoxin and veratridine and suggest a distinct
sub-conductance state stabilized by delta-atracotoxins. Despite these actions,
low concentrations of delta-atracotoxins completely inhibited the binding of the
scorpion alpha-toxin, 125I-Lqh II, indicating that they bind to similar, or
partially overlapping, receptor sites. The apparent uncoupling between the
increase in binding but inhibition of the effect of batrachotoxin induced by
delta-atracotoxins suggests that the binding and action of certain alkaloid
toxins may represent at least two distinguishable steps. These results further
contribute to the understanding of the complex dynamic interactions between
neurotoxin receptor site areas related to sodium channel gating.
PMID- 9765224
TI - Pro-caspase-3 is a major physiologic target of caspase-8.
AB - The apoptotic signal triggered by ligation of members of the death receptor
family is promoted by sequential activation of caspase zymogens. We show here
that in a purified system, the initiator caspases-8 and -10 directly process the
executioner pro-caspase-3 with activation rates (kcat/Km) of 8.7 x 10(5) and 2.8
x 10(5) M-1 s-1, respectively. These rates are of sufficient magnitude to
indicate direct processing in vivo. Differentially processed forms of caspase-3
that accumulate during its activation have similar rates of activation,
activities, and specificities. The pattern and rate of caspase-8 induced
activation of pro-caspase-3 in cytosolic extracts was the same as in a purified
system. Moreover, immunodepletion of a putative intermediary in the pathway to
activation, pro-caspase-9, was without consequence. Taken together these data
demonstrate that the initiator caspase-8 can directly activate pro-caspase-3
without the requirement for an accelerator. The in vitro data thus help to
deconvolute previous in vivo transfection studies which have debated the role of
a direct versus indirect transmission of the apoptotic signal generated by
ligation of death receptors.
PMID- 9765225
TI - Transforming growth factor-beta stimulates the production of
osteoprotegerin/osteoclastogenesis inhibitory factor by bone marrow stromal
cells.
AB - Osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF) is a recently
identified cytokine that belongs to the tumor necrosis factor receptor
superfamily and regulates bone mass by inhibiting osteoclastic bone resorption.
The present study was undertaken to determine whether OPG/OCIF is produced in
bone microenvironment and how the expression is regulated. A transcript for
OPG/OCIF at 3.1 kilobases was detected in bone marrow stromal cells (ST2 and
MC3T3-G2/PA6) as well as in osteoblastic cells (MC3T3-E1). Transforming growth
factor-beta1 (TGF-beta1) markedly increased the steady-state level of OPG/OCIF
mRNA in a dose-dependent manner, while TGF-beta1 suppressed the mRNA expression
of tumor necrosis factor-related activation-induced cytokine (TRANCE)/receptor
activator of NF-kappaB ligand (RANKL), a positive regulator of osteoclastogenesis
to which OPG/OCIF binds. The effect of TGF-beta1 on the expression of OPG/OCIF
mRNA was transient, with a peak level at 3-6 h. The up-regulation of OPG/OCIF
mRNA by TGF-beta1 in ST2 cells did not require de novo protein synthesis and
involved both a transcriptional and a post-transcriptional mechanism. Western
blot analysis and an enzyme-linked immunosorbent assay revealed that TGF-beta1
significantly increased the secretion of OPG/OCIF protein by ST2 cells at 6-24 h.
In murine bone marrow cultures, TGF-beta1 markedly inhibited the formation of
tartrate-resistant acid phosphatase-positive multinucleated osteoclast-like cells
in the presence of 1,25-dihydroxyvitamin D3, whose effect was significantly
reversed by a neutralizing antibody against OPG/OCIF. These results suggest that
TGF-beta1 negatively regulates osteoclastogenesis, at least in part, through the
induction of OPG/OCIF by bone marrow stromal cells and that the balance between
OPG/OCIF and TRANCE/RANKL in local environment may be an important determinant of
osteoclastic bone resorption.
PMID- 9765226
TI - The hepatitis B virus X protein is a co-activator of activated transcription that
modulates the transcription machinery and distal binding activators.
AB - Hepatitis B virus X protein (HBx) transactivates viral and cellular genes through
a wide variety of cis-elements, but the mechanism has not been well elucidated.
Evidence for nuclear events in HBx transactivation has been reported. Here we
examine the role of HBx in modulation of transcription with a transient
transfection system and an in vitro transcription assay. Reporters bearing Gal4
binding sites were applied to avoid the effects of endogenous transcription
factors with or without signaling processes. The Gal4-DNA binding domain fused
form of HBx exhibited no effect on Gal4-responsive reporters. However, HBx
augmented activated transcription by transcriptional activators, suggesting HBx
retains a co-activator but not a transcriptional activator function. The
functional domain for co-activation was the same as that for HBx transactivation,
and the transcription factor IIB- and RNA polymerase II subunit 5-interacting
sites of HBx, which were critical for HBx transactivation, were shown to be
crucial for the co-activation function. Importantly, HBx stimulated transcription
on templates bearing the X responsive elements in vitro with endogenous
activators. These results imply that HBx acts as a co-activator that modulates
transcriptional machinery and distal-binding activators, which may explain one of
the mechanisms of transactivation by HBx when localized in nuclei.
PMID- 9765227
TI - EDG1 is a functional sphingosine-1-phosphate receptor that is linked via a Gi/o
to multiple signaling pathways, including phospholipase C activation, Ca2+
mobilization, Ras-mitogen-activated protein kinase activation, and adenylate
cyclase inhibition.
AB - In Chinese hamster ovary (CHO) cells transiently transfected with an expression
vector for EDG1, but not an empty vector, sphingosine-1-phosphate (SP) at a
concentration as low as 10(-10) M caused an increase in the intracellular free
Ca2+ concentration ([Ca2+]i) as a result of mobilization of Ca2+ from both
intracellular and extracellular pools. In a CHO clone stably expressing EDG1
receptor (CHO-EDG1 cells), SP induced increases in the production of inositol
phosphates and the [Ca2+]i and inhibited forskolin-induced increase in the
cellular cAMP content, all in a manner sensitive to pertussis toxin. SP also
activated mitogen-activated protein kinase in CHO-EDG1 cells in pertussis toxin
sensitive and Ras-dependent manners. To evaluate the spectrum of agonists for
EDG1, we used human erythroleukemia (HEL) cells, which at naive state do not
respond to SP or structurally related lipids with an increase in the [Ca2+]i. In
HEL cells stably expressing EDG1 receptor (HEL-EDG1 cells), SP dose-dependently
increased the [Ca2+]i with half-maximal and maximal concentration values of 10(
9) and 3 x 10(-7) M, respectively; sphingosylphosphorylcholine at exclusively
high concentrations, but not sphingosine at all, also increased the [Ca2+]i. HEL
EDG1 cells bound 32P-labeled SP, which was displaced dose dependently by
unlabeled SP. These results indicate that EDG1, a member of the EDG family G
protein-coupled receptors, is a specific, high-affinity SP receptor.
PMID- 9765228
TI - Carbachol stimulates transactivation of epidermal growth factor receptor and
mitogen-activated protein kinase in T84 cells. Implications for carbachol
stimulated chloride secretion.
AB - We have examined the role of tyrosine phosphorylation in regulation of calcium
dependent chloride secretion across T84 colonic epithelial cells. The calcium
mediated agonist carbachol (CCh, 100 microM) stimulated a time-dependent increase
in tyrosine phosphorylation of a range of proteins (with molecular masses ranging
up to 180 kDa) in T84 cells. The tyrosine kinase inhibitor, genistein (5 microM),
significantly potentiated chloride secretory responses to CCh, indicating a role
for CCh-stimulated tyrosine phosphorylation in negative regulation of CCh
stimulated secretory responses. Further studies revealed that CCh stimulated an
increase in both phosphorylation and activity of the extracellular signal
regulated kinase (ERK) isoforms of mitogen-activated protein kinase. Chloride
secretory responses to CCh were also potentiated by the mitogen-activated protein
kinase inhibitor, PD98059 (20 microM). Phosphorylation of ERK in response to CCh
was mimicked by the protein kinase C (PKC) activator, phorbol myristate acetate
(100 nM), but was not altered by the PKC inhibitor GF 109203X (1 microM). ERK
phosphorylation was also induced by epidermal growth factor (EGF) (100 ng/ml).
Immunoprecipitation/Western blot studies revealed that CCh stimulated tyrosine
phosphorylation of the EGF receptor (EGFr) and increased co-immunoprecipitation
of the adapter proteins, Shc and Grb2, with the EGFr. An inhibitor of EGFr
phosphorylation, tyrphostin AG1478 (1 microM), reversed CCh-stimulated
phosphorylation of both EGFr and ERK. Tyrphostin AG1478 also potentiated chloride
secretory responses to CCh. We conclude that CCh activates ERK in T84 cells via a
mechanism involving transactivation of the EGFr, and that this pathway
constitutes an inhibitory signaling pathway by which chloride secretory responses
to CCh may be negatively regulated.
PMID- 9765229
TI - Specific involvement of G proteins in regulation of serum response factor
mediated gene transcription by different receptors.
AB - Regulation of serum response factor (SRF)-mediated gene transcription by G
protein subunits and G protein-coupled receptors was investigated in transfected
NIH3T3 cells and in a cell line that was derived from mice lacking Galphaq and
Galpha11. We found that the constitutively active forms of the alpha subunits of
the Gq and G12 class of G proteins, including Galphaq, Galpha11, Galpha14,
Galpha16, Galpha12, and Galpha13, can activate SRF in NIH3T3 cells. We also found
that the type 1 muscarinic receptor (m1R) and alpha1-adrenergic receptor (AR)
mediated SRF activation is exclusively dependent on Galphaq/11, while the
receptors for thrombin, lysophosphatidic acid (LPA), thromboxane A2, and
endothelin can activate SRF in the absence of Galphaq/11. Moreover, RGS12 but not
RGS2, RGS4, or Axin was able to inhibit Galpha12 and Galpha13-mediated SRF
activation. And RGS12, but not other RGS proteins, blocked thrombin- and LPA
mediated SRF activation in the Galphaq/11-deficient cells. Therefore, the
thrombin, LPA, thromboxane A2, and endothelin receptors may be able to couple to
Galpha12/13. On the contrary, receptors including beta2- and alpha2-ARs, m2R, the
dopamine receptors type 1 and 2, angiotensin receptors types 1 and 2, and
interleukin-8 receptor could not activate SRF in the presence or absence of
Galphaq/11, suggesting that these receptors cannot couple to endogenous G
proteins of the G12 or Gq classes.
PMID- 9765230
TI - A role for polysialic acid in neural cell adhesion molecule heterophilic binding
to proteoglycans.
AB - The neural cell adhesion molecule (NCAM) is known to participate in both
homophilic and heterophilic binding, the latter including mechanisms that involve
interaction with proteoglycans. The polysialic acid (PSA) moiety of NCAM can
serve as a negative regulator of homophilic binding, but indirect evidence has
suggested that PSA can also be involved in heterophilic binding. We have examined
this potential positive role for PSA in terms of the adhesion of PSA-expressing
mouse F11 cells and chick embryonic brain cells to substrates composed of the
purified heparan sulfate proteoglycans agrin and 6C4. This adhesion was
specifically inhibited by polyclonal anti-NCAM Fab antibodies, monoclonal anti
PSA antibodies, PSA itself, and enzymatic removal of either PSA or heparan
sulfate side chains. By contrast, the adhesion was not affected by
chondroitinase, and cell binding to laminin was not inhibited by any of these
treatments. A specific NCAM-heparan sulfate interaction in this adhesion was
further indicated by its inhibition with monoclonal anti-NCAM Fab antibodies that
recognize the known heparin-binding domain of NCAM and with the HBD-2 peptide
derived from this region, but not with antibodies directed against other regions
of the protein including the homophilic binding region. Together, the results
suggest that PSA can act in vitro either as a receptor in NCAM heterophilic
adhesion or as a promoter of binding between heparan sulfate proteoglycans and
the NCAM heparin-binding domain.
PMID- 9765231
TI - Hormone-evoked elementary Ca2+ signals are not stereotypic, but reflect
activation of different size channel clusters and variable recruitment of
channels within a cluster.
AB - Previous studies of (InsP3)-evoked elementary Ca2+ events suggested a hierarchy
of signals; fundamental events ("Ca2+ blips") arising from single InsP3 receptors
(InsP3Rs), and intermediate events ("Ca2+ puffs") reflecting the coordinated
opening of a cluster of InsP3Rs. The characteristics of such elementary Ca2+
release signals provide insights into the functional interaction and distribution
of InsP3Rs in living cells. Therefore we investigated whether elementary Ca2+
signaling is truly represented by such stereotypic release events. A histogram of
>900 events revealed a wide spread of signal amplitudes (20-600 nM; mean 216 +/-
4 nM; n = 206 cells), which cannot be explained by stochastic variation of a
stereotypic Ca2+ release site. We identified elementary Ca2+ release sites with
consistent amplitudes (<20% difference) and locations with variable amplitudes
(approximately 500% difference). Importantly, within single cells, distinct sites
displayed events with significantly different mean amplitudes. Additional
determinants affecting the magnitude of elementary Ca2+ release were identified
to be (i) hormone concentration, (ii) day-to-day variability, and (iii) a
progressively decreasing Ca2+ release during prolonged stimulation. We therefore
suggest that elementary Ca2+ events are not stereotypic, instead a continuum of
signals can be achieved by either recruitment of entire clusters with different
numbers of InsP3Rs or by a graded recruitment of InsP3Rs within a cluster.
PMID- 9765233
TI - RNA structure inhibits the TRAP (trp RNA-binding attenuation protein)-RNA
interaction.
AB - TRAP (trp RNA-binding attenuation protein) regulates expression of the tryptophan
biosynthetic genes in response to tryptophan in Bacillus subtilis by binding to
two sites containing a series of 9 or 11 (G/U)AG triplet repeats that are
generally separated by two or three spacer nucleotides. Previous mutagenesis
experiments have identified three TRAP residues, Lys-37, Lys-56, and Arg-58 that
are essential for RNA binding. The location of these residues on the TRAP
oligomer supports the proposal that RNA binds TRAP by encircling the TRAP
oligomer. In this work, we show that RNAs containing 11 GAG or UAG repeats
separated by CC dinucleotide spacers (((G/U)AGCC)11) form stable structures that
inhibit binding to TRAP. This conclusion is based on the effects of temperature
and Mg2+ on the affinity of TRAP for RNAs with CC spacers combined with UV
hyperchromicity and circular dichroism. Furthermore, introducing the base
analogue 7-deazaguanosine in the ((G/U)AGCC)11 RNAs stabilized the TRAP-RNA
interaction. This effect was associated with decreased stability of the RNA
structure as measured by circular dichroism spectroscopy. The precise nature of
the structure of the ((G/U)AGCC)11 RNAs is not known but evidence is presented
that it involves noncanonical interactions. We also observed that substitution of
Arg-58 with Lys further reduced the ability of TRAP to interact with structured
RNAs. Since in vivo function of TRAP may involve binding to structured RNAs, we
suggest a potential function for this residue, which is conserved in TRAP from
three different bacilli.
PMID- 9765232
TI - ORC5L, a new member of the human origin recognition complex, is deleted in
uterine leiomyomas and malignant myeloid diseases.
AB - A new member of the human origin recognition complex (ORC) was cloned and
identified as ORC5L. HsORC5p is a 50-kDa protein whose sequence is 38% identical
and 62% similar to ORC5p from Drosophila melanogaster. Two alleles of ORC5L were
identified, one with and one without an evolutionarily conserved purine
nucleotide binding motif. HsORC5p is precipitated from cell extracts with HsORC2p
and HsORC4p, indicating that it is part of the putative human ORC. The bulk of
HsORC5p is in an insoluble nuclear fraction, whereas the other known human ORC
subunits (HsORC1p, HsORC2p, and HsORC4p) are easily extracted in the nuclear
soluble fractions and in S100 (HsORC1p). In addition, we identified an
alternatively spliced mRNA from the same locus (HsORC5T). HsORC5Tp also formed a
complex with HsORC4p but not with HsORC2p, suggesting it may play a regulatory
role in the assembly of different ORC subcomplexes. HsORC5, HsORC5T, and HsORC4
transcripts are abundant in spleen, ovary, and prostate in addition to tissues
with high levels of DNA replication like testes and colon mucosa, implicating the
human ORC proteins in functions besides DNA replication. Finally, the gene for
ORC5L is located at chromosome 7, band q22, in the minimal region deleted in 10%
of uterine leiomyomas and in 10-20% of acute myeloid leukemias and
myelodysplastic syndromes.
PMID- 9765234
TI - Newly discovered archaebacterial flap endonucleases show a structure-specific
mechanism for DNA substrate binding and catalysis resembling human flap
endonuclease-1.
AB - Mammalian flap endonuclease-1 (FEN-1) is a structure-specific metalloenzyme that
acts in processing of both the Okazaki fragments during lagging strand DNA
synthesis and flap intermediates during DNA damage repair. We identified and
cloned three open reading frames encoding a flap endonuclease from Archaeglobus
fulgidus, Methanococcus jannaschii, and Pyrococcus furiosus, respectively. The
deduced FEN-1 protein sequences share approximately 75% similarity with the human
FEN-1 nuclease in the conserved nuclease domains, and extensive biochemical
experiments indicate that the substrate specificities and catalytic activities of
these enzymes have overall similarities with those of the human enzyme. Thus, FEN
1 enzymes and likely reaction mechanisms are conserved across the eukaryotic and
archaeal kingdoms. Detailed comparative analysis, however, reveals subtle
differences among these four enzymes including distinctive substrate specificity,
tolerance of the archaebacterial enzymes for acidic pHs and elevated
temperatures, and variations in the metal-ion dependence of substrate cleavage.
Although the archaebacterial enzymes were inactive at temperatures below 30
degreesC, DNA binding occurred at temperatures as low as 4 degreesC and with or
without metal ions. Thus, these archaeal enzymes may provide a means to dissect
the specific binding and catalytic mechanisms of the entire FEN-1 family of
structure-specific nucleases.
PMID- 9765235
TI - Compartmentation of lactate and glucose metabolism in C6 glioma cells. A 13c and
1H NMR study.
AB - 13C and 1H NMR spectroscopy was used to investigate the metabolism of L-lactate
and D-glucose in C6 glioma cells. The changing of lactate and glucose
concentration in the extracellular medium of C6 glioma cells incubated with 5.5
mM glucose and 11 mM lactate indicated a net production of lactate as the
consequence of an active aerobic glycolysis. The 13C enrichments of various
metabolites were determined after 4-h cell incubation in media containing both
substrates, each of them being alternatively labeled in the form of either [3
13C]L-lactate or [1-13C]D-glucose. Using 11 mM [3-13C]L-lactate, the enrichment
of glutamate C4, 69%, was found higher than that of alanine C3, 32%, when that of
acetyl-CoA C2 was 78%. These results indicated that exogenous lactate was the
major substrate for the oxidative metabolism of the cells. Nevertheless, an
active glycolysis occurred, leading to a net lactate production. This lactate
was, however, metabolically different from the exogenous lactate as both lactate
species did not mix into a unique compartment. The results were actually
consistent with the concept of the existence of two pools of both lactate and
pyruvate, wherein one pool was closely connected with exogenous lactate and was
the main fuel for the oxidative metabolism, and the other pool was closely
related to aerobic glycolysis.
PMID- 9765236
TI - Purinergic receptor modulation of lipopolysaccharide signaling and inducible
nitric-oxide synthase expression in RAW 264.7 macrophages.
AB - Previous studies have suggested that the P2Z/P2X7 purinergic receptor can
participate in nucleotide-induced modulation of lipopolysaccharide (LPS)
stimulated inflammatory mediator production. To test this hypothesis, we
evaluated whether antagonism of the P2Z/P2X7 receptor can influence LPS signaling
and expression of the inducible form of nitric-oxide synthase (iNOS) in RAW 264.7
macrophages. In the present study, we demonstrate that pretreatment of RAW 264.7
macrophages with a P2Z/P2X7 receptor antagonist, periodate oxidized adenosine 5'
triphosphate (o-ATP), substantially inhibits LPS-stimulated NO production and
iNOS expression without altering cell viability. This effect on LPS-induced iNOS
expression is mimicked by a pyridoxal-phosphate-based antagonist (pyridoxal
phosphate-6-azophenyl-2',4'-disulfonic acid) of the P2Z/P2X7 purinergic receptor,
indicating that these results are not unique to o-ATP. Additionally, o-ATP
prevents cell death induced by P2Z/P2X7 receptor agonists. To ascertain how
P2Z/P2X7 receptor antagonists influence LPS signaling, we evaluated the capacity
of o-ATP to regulate LPS-mediated activation of the transcription factor, nuclear
factor-kappaB, and the mitogen-activated protein kinases, extracellular signal
regulated kinase (ERK) 1 and ERK2. These experiments reveal that pretreatment of
RAW 264.7 cells with o-ATP attenuates the LPS stimulation of a nuclear factor
kappaB-like binding activity. Moreover, the activation of ERK1 and ERK2 by LPS,
but not by the phorbol ester, phorbol 12-myristate 13-acetate, is also blocked in
RAW 264.7 cells by o-ATP pretreatment. In summary, these data suggest that the
P2Z/P2X7 receptor modulates LPS-induced macrophage activation as assessed by iNOS
expression and NO production. This report implicates the P2Z/P2X7 receptor in the
control of protein kinase cascades and transcriptional processes, and these
observations are likely to be important for the development of selective
purinergic receptor antagonists for the treatment of septic shock.
PMID- 9765237
TI - A study of the mechanism of inhibition of fibrinolysis by activated thrombin
activable fibrinolysis inhibitor.
AB - TAFI (thrombin-activable fibrinolysis inhibitor) is a recently described plasma
zymogen that, when exposed to the thrombin-thrombomodulin complex, is converted
by proteolysis at Arg92 to a basic carboxypeptidase that inhibits fibrinolysis
(TAFIa). The studies described here were undertaken to elucidate the molecular
basis for the inhibition of fibrinolysis. When TAFIa is included in a clot
undergoing fibrinolysis induced by tissue plasminogen activator and plasminogen,
the time to achieve lysis is prolonged, and free arginine and lysine are released
over time. In addition, TAFIa prevents a 2.5-fold increase in the rate constant
for plasminogen activation which occurs when fibrin is modified by plasmin in the
early course of fibrin degradation. The effect is specific for the Glu- form of
plasminogen. TAFIa prevents or at least attenuates positive feedback expressed
through Lys-plasminogen formation during the process of fibrinolysis initiated by
tissue plasminogen activator and plasminogen. TAFIa also inhibits plasmin
activity in a clot and prolongs fibrinolysis initiated with plasmin. We conclude
that TAFIa suppresses fibrinolysis by removing COOH-terminal lysine and arginine
residues from fibrin, thereby reducing its cofactor functions in both plasminogen
activation and the positive feedback conversion of Glu-plasminogen to Lys
plasminogen. At relatively elevated concentrations, it also directly inhibits
plasmin.
PMID- 9765238
TI - Structure-function study of a heptad repeat positioned near the transmembrane
domain of Sendai virus fusion protein which blocks virus-cell fusion.
AB - A synthetic heptad repeat, SV-473, derived from Sendai virus fusion protein is a
potent inhibitor of virus-cell fusion. In order to understand the mechanism of
the inhibitory effect, we synthesized and fluorescently labeled SV-465, an
extended version of SV-473 by one more heptad, its mutant peptide A17,24-SV-465,
in which two heptadic leucines were substituted with two alanines, and its
enatiomer D-SV-465, composed entirely of Damino acids. Similar mutations in the
homologous fusion protein of the Newcastle disease virus drastically reduced its
activity. The data revealed that SV-465, but not A17,24-SV-465 or its enantiomer,
is highly active in inhibiting Sendai virus-induced hemolysis of red blood cells.
None of the peptides interfere with the binding of virions to the target red
blood cells as demonstrated by hemagglutinin assay. Fluorescence and circular
dichroism (CD) spectroscopy indicated that: (i) only SV-465 could self-assemble
in aqueous environment; (ii) only SV-465 could co-assemble with two other
biologically active heptad repeats derived from Sendai virus fusion protein;
(iii) SV-465 has a higher helical content than A17,24-SV-465 in solution, and
(iv) all the peptides bind strongly to zwitterionic and negatively charged
phospholipids. Polarized attenuated total reflection infrared spectroscopy
revealed that they bound as monomers onto the surface of zwitterionic membranes
with predominantly alpha-helical structures. The functional role of the amino
acid 465-497 domain in Sendai virus-mediated membrane fusion is discussed in
light of these findings.
PMID- 9765239
TI - The influence of apolipoproteins on the hepatic lipase-mediated hydrolysis of
high density lipoprotein phospholipid and triacylglycerol.
AB - This study describes the influence of apolipoproteins on the hepatic lipase (HL)
mediated hydrolysis of phospholipids and triacylglycerol in high density
lipoproteins (HDL). HL-mediated hydrolysis was assessed in well characterized,
homogeneous preparations of spherical reconstituted high density lipoproteins
(rHDL). The rHDL were comparable in size and lipid composition and contained
either apoA-I ((A-I)rHDL) or apoA-II ((A-II)rHDL) as their sole apolipoprotein
constituent. Preparations of rHDL containing only cholesteryl esters (CE) in
their core, (A-I/CE)rHDL and (A-II/CE)rHDL, were used to assess phospholipid
hydrolysis. Preparations of rHDL that contained triacylglycerol as their
predominant core lipid, (A-I/TG)rHDL and (A-II/TG)rHDL, were used to assess both
triacylglycerol and phospholipid hydrolysis. The rHDL contained trace amounts of
either radiolabeled phospholipid or radiolabeled triacylglycerol. Hydrolysis was
measured as the release of radiolabeled nonesterified fatty acids (NEFA) from the
rHDL. Kinetic analysis showed that HL had a greater affinity for the
phospholipids in (A-II/CE)rHDL (Km(app) = 0.2 mM) than in (A-I/CE)rHDL (Km(app) =
3.1 mM). This was also evident when hydrolysis was measured directly by
quantitating NEFA mass. HL also had a greater affinity for the phospholipids and
triacylglycerol in (A-II/TG)rHDL than in (A-I/TG)rHDL. The Vmax for phospholipid
hydrolysis was, by contrast, greater for (A-I/CE)rHDL than for (A-II/CE)rHDL:
309.3 versus 49.1 nmol of NEFA formed/ml of HL/h. Comparable Vmax values were
obtained for the hydrolysis of the phospholipids in (A-II/TG)rHDL and (A
I/TG)rHDL. In the case of triacylglycerol hydrolysis, the respective Vmax values
for (A-I/TG)rHDL and (A-II/TG)rHDL were 1154.8 and 240.2 nmol of NEFA formed/ml
of HL/h. These results show that apolipoproteins have a major influence on the
kinetics of HL-mediated phospholipid and triacylglycerol hydrolysis in rHDL.
PMID- 9765240
TI - Identification of free deaminated sialic acid (2-keto-3-deoxy-D-glycero-D-galacto
nononic acid) in human red blood cells and its elevated expression in fetal cord
red blood cells and ovarian cancer cells.
AB - Chemical studies have shown the occurrence of the deaminated sialic acid 2-keto-3
deoxy-D-glycero-D-galacto-nononic acid (KDN) in paired samples of blood obtained
from mothers and newborns of healthy human individuals. Most of the KDN was found
in red blood cells, although low levels were detected in mononuclear cells. No N
glycolylneuraminic acid was detected. Unexpectedly, nearly all of the KDN in
fetal cord and matched maternal red blood cells was present as the free sugar and
comparatively little occurred conjugated or as cytidine 5'-KDN phosphate. The
amount of free KDN in fetal newborn red blood cells was 2.4-fold higher than in
red blood cells from the mothers or from healthy nonpregnant women. Free KDN was
also identified in normal human ovaries, in ovarian tumors, and in ascites cells
obtained from ovarian cancer patients. Importantly, as in fetal cord red blood
cells, a distinguishing feature of KDN expression in ovarian tumor cells was an
elevated level of free KDN compared with normal controls. A positive correlation
was found between an increase in the ratio of free KDN/N-acetylneuraminic acid in
ovarian adenocarcinomas and the stage of malignancy. This was particularly
evident in tumor cells isolated from the ascites fluid. The central importance of
these new findings is 2-fold. First, they show that free KDN is a minor but
ubiquitous sialic acid in human red blood cells and that its elevated expression
in red blood cells from fetal cord blood compared with maternal red blood cells
may be developmentally related to blood cell formation during embryogenesis.
Second, the enhanced expression of KDN in ovarian cancer cells suggests that this
sialic acid, like the alpha2,8-linked polysialic acid glycotope, may be an
oncofetal antigen in these tumors and thus could be an "early warning" signal for
onset of disease and/or a marker for detection of recurrence of disease. These
new findings highlight the importance of elucidating the role that KDN and KDN
containing glycoconjugates may play in normal development and malignancy.
PMID- 9765241
TI - Molecular mechanism of diltiazem interaction with L-type Ca2+ channels.
AB - Benzothiazepine Ca2+ antagonists (such as (+)-cis-diltiazem) interact with
transmembrane segments IIIS6 and IVS6 in the alpha1 subunit of L-type Ca2+
channels. We investigated the contribution of individual IIIS6 amino acid
residues for diltiazem sensitivity by employing alanine scanning mutagenesis in a
benzothiazepine-sensitive alpha1 subunit chimera (ALDIL) expressed in Xenopus
laevis oocytes. The most dramatic decrease of block by 100 microM diltiazem
(ALDIL 45 +/- 4.8% inhibition) during trains of 100-ms pulses (0.1 Hz, -80 mV
holding potential) was found after mutation of adjacent IIIS6 residues Phe1164(21
+/- 3%) and Val1165 (8.5 +/- 1.4%). Diltiazem delayed current recovery by
promoting a slowly recovering current component. This effect was similar in ALDIL
and F1164A but largely prevented in V1165A. Both mutations slowed inactivation
kinetics during a pulse. The reduced diltiazem block can therefore be explained
by slowing of inactivation kinetics (F1164A and V1165A) and accelerated recovery
from drug block (V1165A). The bulkier diltiazem derivative benziazem still
efficiently blocked V1165A. From these functional and from additional radioligand
binding studies with the dihydropyridine (+)-[3H]isradipine we propose a model in
which Val1165 controls dissociation of the bound diltiazem molecule, and where
bulky substituents on the basic nitrogen of diltiazem protrude toward the
adjacent dihydropyridine binding domain.
PMID- 9765242
TI - A new type of cytokine receptor antagonist directly targeting gp130.
AB - The interleukin-6-type family of cytokines bind to receptor complexes that share
gp130 as a common signal-transducing subunit. So far, receptor antagonists for
interleukin-6-type cytokines have been constructed that still bind to the
specific ligand binding subunit of the receptor complex, but have lost the
ability to stimulate gp130. Such receptor antagonists compete for a specific
receptor of a member of the cytokine family. Interleukin-6 only binds to gp130
when complexed with the interleukin-6 receptor that exists as a membrane bound
and soluble molecule. Here we have constructed fusion proteins that consist of
the soluble form of the human interleukin-6 receptor covalently linked to
interleukin-6 receptor antagonists. These fusion proteins directly bind to gp130.
Moreover, at concentrations of 10-50 nM they completely neutralize not only the
biological activity of interleukin-6 but also of other cytokines of the
interleukin-6-type family that act via gp130 homodimers or gp130/LIF-R
heterodimers. Therefore, these gp130 targeting cytokine antagonists might be
useful therapeutic tools in disease states that are related to cytokines of the
interleukin-6 family.
PMID- 9765243
TI - Human procarboxypeptidase U, or thrombin-activable fibrinolysis inhibitor, is a
substrate for transglutaminases. Evidence for transglutaminase-catalyzed cross
linking to fibrin.
AB - Procarboxypeptidase U (EC 3.4.17.20) (pro-CpU), also known as plasma
procarboxypeptidase B and thrombin-activable fibrinolysis inhibitor, is a human
plasma protein that has been implicated in the regulation of fibrinolysis. In
this study, we show that pro-CpU serves as a substrate for transglutaminases.
Both factor XIIIa and tissue transglutaminase catalyzed the polymerization of pro
CpU and the cross-linking to fibrin as well as the incorporation of 5
dimethylaminonaphthalene-1-sulfonyl cadaverine (dansylcadaverine),
[14C]putrescine, and dansyl-PGGQQIV. These findings show that pro-CpU contains
both amine acceptor (Gln) and amine donor (Lys) residues. The amine acceptor
residues were identified as Gln2, Gln5, and Gln292, suggesting that both the
activation peptide and the mature enzyme participate in the cross-linking
reaction. These observations imply that transglutaminases may mediate covalent
binding of pro-CpU to other proteins and cell surfaces in vivo. In particular,
factor XIIIa may cross-link pro-CpU to fibrin during the latter part of the
coagulation cascade, thereby helping protect the newly formed fibrin clot from
premature plasmin degradation. Moreover, the cross-linking may facilitate the
activation of pro-CpU, stabilize the enzymatic activity, and protect the active
enzyme from further degradation.
PMID- 9765244
TI - Proteasome-mediated degradation of apolipoprotein B targets both nascent peptides
cotranslationally before translocation and full-length apolipoprotein B after
translocation into the endoplasmic reticulum.
AB - A major portion of newly synthesized apolipoprotein B (apoB) is degraded
intracellularly. This degradation has been demonstrated to be mediated largely by
the ubiquitin-proteasome pathway. We examined whether nascent apoB polypeptides
or full-length apoB is selectively retrotranslocated from the endoplasmic
reticulum into the cytosol for degradation. Herein, we found that full-length
apoB as well as partial-length apoB peptides are ubiquitinated in HepG2 cells,
and ubiquitination is an exclusively cytosolic process. Calnexin, which binds
specifically to glycoproteins, has been postulated to promote apoB folding and
complete translocation; we found that ubiquitinated apoB is bound to calnexin,
suggesting that ubiquitinated apoB is glycosylated. In addition to calnexin
binding, we have other pieces of evidence that the full-length intracellular
ubiquitinated apoB is glycosylated, because (i) it binds to concanavalin A, and
(ii) glycan can be demonstrated in the full-length ubiquitinated apoB by a
chemical detection method involving oxidation of adjacent hydroxyl groups in the
glycan moiety. Because glycosylation occurs inside the endoplasmic reticulum, the
full-length glycosylated apoB must have been retrotranslocated into the cytosol
for ubiquitination and proteasome-mediated degradation. Next we synchronized
translation in HepG2 cells by puromycin treatment. A pulse-chase experiment using
[35S]methionine labeling of intracellular apoB in these synchronized cells
demonstrated that nascent partial-length apoB peptides are also ubiquitinated
cotranslationally. We conclude that the ubiquitin proteasome-mediated degradation
of apoB targets both nascent peptides cotranslationally before translocation as
well as full-length apoB after its translocation into the endoplasmic reticulum.
PMID- 9765246
TI - GroEL and GroES control of substrate flux in the in vivo folding pathway of phage
P22 coat protein.
AB - Our present understanding of the action of the chaperonins GroEL/S on protein
folding is based primarily on in vitro studies, whereas the folding of proteins
in the cellular milieu has not been as thoroughly investigated. We have developed
a means of examining in vivo protein folding and assembly that utilizes the coat
protein of bacteriophage P22, a naturally occurring substrate of GroEL/S. Here we
show that amino acid substitutions in coat protein that cause a temperature
sensitive-folding (tsf) phenotype slowed assembly rates upon increasing the
temperature of cell growth. Raising cellular concentrations of GroEL/S increased
the rate of assembly of the tsf mutant coat proteins to nearly that of wild-type
(WT) coat protein by protecting a thermolabile folding intermediate from
aggregation, thereby increasing the concentration of assembly-competent coat
protein. The rate of release of the tsf coat proteins from the GroEL/S-coat
protein ternary complex was approximately 2-fold slower at non-permissive
temperatures when compared with the release of WT coat protein. However, the rate
of release of WT or tsf coat proteins at each temperature remained constant
regardless of GroEL/S levels. Thus, raising the cellular concentration of GroEL/S
increased the amount of assembly-competent tsf coat proteins not by altering the
rates of folding but by increasing the probability of GroEL/S-coat protein
complex formation.
PMID- 9765245
TI - A K+ channel splice variant common in human heart lacks a C-terminal domain
required for expression of rapidly activating delayed rectifier current.
AB - We have cloned HERG USO, a C-terminal splice variant of the human ether-a-go-go
related gene (HERG), the gene encoding the rapid component of the delayed
rectifier (IKr), from human heart, and we find that its mRNA is approximately 2
fold more abundant than that for HERG1 (the originally described cDNA). After
transfection of HERG USO in Ltk- cells, no current was observed. However,
coexpression of HERG USO with HERG1 modified IKr by decreasing its amplitude,
accelerating its activation, and shifting the voltage dependence of activation
8.8 mV negative. As with HERG USO, HERGDeltaC (a HERG1 construct lacking the C
terminal 462 amino acids) also produced no current in transfected cells. However,
IKr was rescued by ligation of 104 amino acids from the C terminus of HERG1 to
the C terminus of HERGDeltaC, indicating that the C terminus of HERG1 includes a
domain (=104 amino acids) that is critical for faithful recapitulation of IKr.
The lack of this C-terminal domain not only explains the finding that HERG USO
does not generate IKr but also indicates a similar mechanism for hitherto
uncharacterized long QT syndrome HERG mutations that disrupt the splice site or
the C-terminal. We suggest that the amplitude and gating of cardiac IKr depends
on expression of both HERG1 and HERG USO.
PMID- 9765247
TI - Induction of topoisomerase I cleavage complexes by the vinyl chloride adduct 1,N6
ethenoadenine.
AB - We used purified mammalian topoisomerases I (top1) and oligonucleotides to study
top1-mediated cleavage and religation in the presence of a potent carcinogenic
adduct, 1,N6-ethenoadenosine (epsilonA) incorporated immediately downstream of a
unique top1 cleavage site. We found tha epsilonA markedly enhanced top1 cleavage
complexes when it was incorporated at the +1 position of the top1 cleavage. This
enhancement was due to a reduction of the religation step of the top1 reaction.
In addition, epsilonA reduced the top1-mediated cleavage and decreased binding of
the enzyme to DNA. We also studied the effects of the epsilonA adduct on top1
trapping by camptothecin (CPT), a well known top1 inhibitor. CPT was inactive
when epsilonA was present at the +1 position. Alkylation of the top1 cleavage
complex by 7-chloromethyl-10,11-methylenedioxycamptothecin (7-ClMe-MDO-CPT) was
also blocked by the epsilonA adduct. Altogether, these results demonstrate that
the epsilonA carcinogenic adduct can efficiently trap human top1 and mimic CPT
effects. Normal hydrogen bonding of the base pairs immediately downstream from
the top1 cleavage site is probably essential for efficient DNA religation and
binding of camptothecins in the top1 cleavage complex.
PMID- 9765248
TI - Selective inhibition of HIV-1 reverse transcriptase by an antiviral inhibitor,
(R)-9-(2-Phosphonylmethoxypropyl)adenine.
AB - (R)-9-(2-Phosphonylmethoxypropyl)adenine (PMPA) is an acyclic nucleoside
phosphonate that has been shown to be effective in the treatment of AIDS although
it has a shorter separation between the adenine and phosphorus than dideoxy-AMP
and dAMP. By using pre-steady state kinetic methods, we examined the
incorporation of the diphosphate of PMPA, 2',3'-dideoxyadenosine 5'-triphosphate
(ddATP), and dATP catalyzed by wild-type human immunodeficiency virus type 1 (HIV
1) reverse transcriptase, an exonuclease-deficient T7 DNA polymerase (T7 exo-),
and wild-type rat DNA polymerase beta in order to evaluate the selectivity of
PMPA as an antiviral inhibitor. With a DNA/DNA or DNA/RNA 22/43-mer duplex, the
diphosphate of PMPA (PMPApp) is as effective as ddATP in reactions catalyzed by
HIV-1 reverse transcriptase in that both analogs have similar substrate
specificity constants (kp/Kd) which are only 5-fold lower than dATP. In contrast,
PMPApp is a much weaker inhibitor of the reaction catalyzed by T7 exo- (with the
DNA/DNA 22/43-mer duplex) in that PMPApp has a 5 x 10(-4)-fold lower kp/Kd than
ddATP and dATP. The lower kp/Kd of PMPApp is due to a 1000-2000-fold lower
incorporation rate (kp) and a 35-45-fold lower binding constant (Kd). Similarly,
PMPApp is 800-fold less inhibitory toward polymerase beta with the DNA/DNA 22/43
mer duplex, whereas in studies with a single nucleotide gapped DNA (22-20/43-mer)
PMPApp is 13-fold less inhibitory than ddATP. Although parallel studies will need
to be performed using appropriate human polymerases, these results begin to
define the mechanistic basis for the reported lower toxicity of PMPA in the
treatment of AIDS.
PMID- 9765249
TI - DNA secondary structure effects on DNA synthesis catalyzed by HIV-1 reverse
transcriptase.
AB - The effect of DNA secondary structure on polymerization catalyzed by human
immunodeficiency virus (HIV-1) reverse transcriptase (RT) was studied using a
synthetic 66-nucleotide DNA template containing a stable hairpin structure. Four
RT pause sites were identified within the first half of the hairpin stem.
Additionally, five weak pause sites within the second half of the stem and the
loop of the hairpin were identified at low temperatures. These weak pause sites
were relocated to the site of the first few stem base pairs of two new hairpins
formed due to a change in DNA secondary structure. Each pause site was correlated
with a high free energy barrier of melting the stem base pair. Pre-steady state
kinetic analysis of single nucleotide incorporation showed that polymerization at
each pause site occurred by both a fast phase (10-20 s-1) and a slow phase (0. 02
0.07 s-1) during a single binding event. The reaction amplitudes of the fast
phase were small (4-10% of enzyme sites), whereas the amplitudes of the slow
phase were large (14-40%) at the pause sites. In contrast, only a single phase
with a large reaction amplitude (32-50%) and a fast nucleotide incorporation rate
(33-87 s-1) was observed at the non-pause sites. DNA substrates at all sites had
similar dissociation rates (0.14-0.29 s-1) and overall binding affinity (16-86
nM). These results suggest that the DNA substrates at pause sites were bound in
both productive and non-productive states at the polymerase site of RT. The non
productively bound DNA was slowly converted into a productive state upon melting
of the next stem base pair without dissociation of the DNA from RT.
PMID- 9765250
TI - Distinct mechanisms mediate the initial and sustained phases of integrin-mediated
activation of the Raf/MEK/mitogen-activated protein kinase cascade.
AB - Integrin-mediated adhesion to the extracellular matrix activates the canonical
mitogen-activated protein kinase cascade, although the exact mechanism is not
fully resolved. We show that integrin-mediated activation of Raf-1, an upstream
regulator of mitogen-activated protein kinase, occurs in two phases. Efficient
early activation of Raf required Raf-Ras interaction but was not affected by
protein kinase C (PKC) inhibitors, while a lower, sustained level of activity was
independent of Raf-Ras interaction but was reduced by PKC inhibitors. The
combination of PKC inhibition and lack of Ras binding completely blocked integrin
mediated Raf activity. The activity of a membrane-bound Raf mutant that is
deficient in Ras binding (Raf-R89L-CAAX) was also regulated by adhesion. Raf-R89L
CAAX activity was low in nonadherent cells, was rapidly stimulated to wild-type
levels by cell adhesion, and remained at nearly maximal levels longer than wild
type activity. The activation of wild-type and mutant Raf proteins was ablated by
cytochalasin D, demonstrating that cytoskeletal organization is required for
activation of Raf, even when targeted to the membrane. These data suggest
distinct initial and sustained phases of integrin-mediated Raf activation that
require Raf membrane localization and possibly PKC activity, respectively, and
that integrin-mediated adhesion may regulate a cytoskeleton-associated factor(s)
responsible for Raf activation.
PMID- 9765251
TI - Promiscuous coupling of receptors to Gq class alpha subunits and effector
proteins in pancreatic and submandibular gland cells.
AB - Mice with deficiencies in one or more Gq class alpha subunit genes were used to
examine the role of the alpha subunit in regulating Ca2+ signaling in pancreatic
and submandibular gland cells. Western blot analysis showed that these cells
express three of the four Gq class subunits, Galphaq, Galpha11, and Galpha14 but
not Galpha15. Surprisingly, all parameters of Ca2+ signaling were identical in
cells from wild type and four lines of mutant mice: 1) Galpha11-/-, 2) Galpha11-/
/Galpha14-/-, 3) Galpha14-/-/Galpha15-/-, and 4) Galphaq-/-/Galpha15-/-. These
parameters included the Kapp for several Gq class coupled receptors, induction of
[Ca2+]i oscillations by weak stimulation, and a biphasic [Ca2+]i response by
strong stimulation. Furthermore, Ca2+ release from internal stores and Ca2+ entry
were not affected in cells from any of the mutant mice. We conclude that Galphaq,
Galpha11, and Galpha14 promiscuously couple several receptors (m3 muscarinic,
bombesin, cholecystokinin, and alpha1 adrenergic) to effector proteins that
activate both Ca2+ release from internal stores and Ca2+ entry.
PMID- 9765252
TI - Lack of tyrosine nitration by peroxynitrite generated at physiological pH.
AB - Nitration of tyrosine residues of proteins has been suggested as a marker of
peroxynitrite-mediated tissue injury in inflammatory conditions. The nitration
reaction has been extensively studied in vitro by bolus addition of authentic
peroxynitrite, an experimental approach hardly reflecting in vivo situations in
which the occurrence of peroxynitrite is thought to result from continuous
generation of .NO and O-2 at physiological pH. In the present study, we measured
the nitration of free tyrosine by .NO and O-2 generated at well defined rates
from the donor compound (Z)-1-[N-[3-aminopropyl]-N-[4-(3
aminopropylammonio)butyl]-amino]- dia zen-1-ium-1,2-diolate] (spermine NONOate)
and the xanthine oxidase reaction, respectively. The results were compared with
the established nitration reaction triggered by authentic peroxynitrite. Bolus
addition of peroxynitrite (1 mM) to tyrosine (1 mM) at pH 7.4 yielded 36.77 +/-
1.67 microM 3-nitrotyrosine, corresponding to a recovery of about 4%. However,
peroxynitrite formed from .NO and O-2, which were generated at equal rates (
approximately 5 microM x min-1) from 1 mM spermine NONOate, 28 milliunits/ml
xanthine oxidase, and 1 mM hypoxanthine was much less efficient (0.67 +/- 0.01
microM; approximately 0.07% of total product flow). At O-2 fluxes exceeding the
.NO release rates, 3-nitrotyrosine formation was below the detection limit of the
high performance liquid chromatography method (<0.06 microM). Nitration was most
efficient (approximately 0.3%) with the .NO donor alone, i.e. without concomitant
generation of O-2. Nitration by .NO had a pH optimum of 8.2, increased
progressively with increasing tyrosine concentrations (0.1-2 mM), and was not
enhanced by NaHCO3 (up to 20 mM), indicating that it was mediated by .NO2 rather
than peroxynitrite. Our results argue against peroxynitrite produced from .NO and
O-2 as a mediator of tyrosine nitration in vivo.
PMID- 9765253
TI - Hypo-osmotic shock of tobacco cells stimulates Ca2+ fluxes deriving first from
external and then internal Ca2+ stores.
AB - Hypo-osmotic shock of aequorin-transformed tobacco cells induces a biphasic
cytosolic Ca2+ influx. Because both phases of Ca2+ entry are readily blocked by
Ca2+ channel inhibitors, we conclude that the Ca2+ transients are mediated by
Ca2+ channels. Evidence that the first but not second Ca2+ transient derives from
external Ca2+ stores is that the first but not second influx is (i) eliminated by
membrane-impermeable Ca2+ chelators, (ii) enlarged by supplementation of the
medium with excess Ca2+, and (iii) reduced by the addition of competitive cations
such as Mg2+ and Mn2+. Furthermore, entry of 45Ca during osmotic shock is
prevented by inhibitors of the first but not second phase of Ca2+ entry. Evidence
that the second wave of Ca2+ influx stems from release of intracellular Ca2+ is
based on the above data plus observations that probable modulators of
intracellular Ca2+ channels selectively block this phase of Ca2+ influx. Finally,
a mechanism of communication between the two Ca2+ release pathways has become
apparent, since perturbations that elevate or reduce the first Ca2+ transient
lead to a compensating diminution/elevation of the second and vice versa. These
data thus suggest that osmotic shock leads to the sequential opening of
extracellular followed by intracellular Ca2+ stores and that these Ca2+ release
pathways are internally compensated.
PMID- 9765254
TI - Selective role for beta-protein kinase C in signaling for O-2 generation but not
degranulation or adherence in differentiated HL60 cells.
AB - A role for protein kinase C (PKC) isotypes is implicated in the activation of
phagocytic cell functions. An antisense approach was used to selectively deplete
beta-PKC, both betaI- and betaII-PKC, but not alpha-PKC, delta-PKC, or zeta-PKC
in HL60 cells differentiated to a neutrophil-like phenotype (dHL60 cells).
Depletion of beta-PKC in dHL60 cells elicited selective inhibition of O-2
generation triggered by fMet-Leu-Phe, immune complexes, or phorbol myristate
acetate, an activator of PKC. In contrast, neither ligand-elicited beta
glucuronidase (azurophil granule) release nor adherence to fibronectin was
inhibited by beta-PKC depletion. Ligand-induced phosphorylation of a subset of
proteins was reduced in beta-PKC-depleted dHL60 cells. Phosphorylation of
p47(phox) and translocation of p47(phox) to the membrane are essential for
activation of the NADPH oxidase and generation of O-2. beta-PKC depletion had no
effect on the level of p47(phox) in dHL60 cells but did significantly decrease
ligand-induced phosphorylation of this protein. Furthermore, translocation of
p47(phox) to the membrane in response to phorbol myristate acetate or fMet-Leu
Phe was reduced in beta-PKC-depleted cells. These results indicate that beta-PKC
is essential for signaling for O-2 generation but not cell adherence or azurophil
degranulation. Depletion of beta-PKC inhibited ligand-induced phosphorylation of
p47(phox), translocation of p47(phox) to the membrane, and activation of O-2
generation.
PMID- 9765255
TI - Platelet-derived growth factor-BB and thrombin generate positive and negative
signals for human hepatic stellate cell proliferation. Role of a
prostaglandin/cyclic AMP pathway and cross-talk with endothelin receptors.
AB - Proliferation of myofibroblastic hepatic stellate cells (HSC) in response to
growth factors is essential for the development of liver fibrosis. We have
reported that prostaglandins (PG) and cyclic AMP (cAMP) inhibit growth of human
HSC. This PG/cAMP pathway transduces the endothelin (ET) B-mediated
antiproliferative effect of endothelin-1 (ET-1) and up-regulates ETB receptors.
Here, we show that platelet-derived growth factor (PDGF)-BB and thrombin,
although mitogenic, generate growth inhibitory PGE2 in myofibroblastic human HSC.
The two peptides elicit early PGE2 and cAMP synthesis, and also promote delayed
induction of cyclooxygenase (COX)-2. Both early and delayed production of PGE2
counteract the mitogenic effect of PDGF-BB and thrombin because: (i) pretreatment
with the COX inhibitor ibuprofen markedly enhances the mitogenic effect of both
peptides; (ii) blocking early synthesis of PGE2 greatly enhances extracellular
signal-regulated kinase (ERK) activation by both growth factors; (iii)
enhancement of DNA synthesis by ibuprofen is only lost when the inhibitor is
added after COX-2 induction has occurred. Finally, PDGF-BB and thrombin raise ETB
receptors through the PG pathway. Thus, ibuprofen blunts growth factor-induced
increase in ETB receptors. Up-regulation of the growth inhibitory ETB receptors
by both mitogens may enhance the antiproliferative effect of ET-1 and thereby
establish a negative feedback of their mitogenic effect. Our results shed light
on novel growth inhibitory signals evoked by two mitogenic growth factors
expressed during liver injury.
PMID- 9765256
TI - Prostaglandin E2 Up-regulates HIV-1 long terminal repeat-driven gene activity in
T cells via NF-kappaB-dependent and -independent signaling pathways.
AB - Replication of human immunodeficiency virus type-1 (HIV-1) is highly dependent on
the state of activation of the infected cells and is modulated by interactions
between viral and host cellular factors. Prostaglandin E2 (PGE2), a pleiotropic
immunomodulatory molecule, is observed at elevated levels during HIV-1 infection
as well as during the course of other pathogenic infections. In 1G5, a Jurkat
derived T cell line stably transfected with a luciferase gene driven by HIV-1
long terminal repeat (LTR), we found that PGE2 markedly enhanced HIV-1 LTR
mediated reporter gene activity. Experiments have been conducted to identify
second messengers involved in this PGE2-dependent up-regulating effect on the
regulatory element of HIV-1. In this study, we present evidence indicating that
signal transduction pathways induced by PGE2 necessitate the participation of
cyclic AMP, protein kinase A, and Ca2+. Experiments conducted with different HIV
1 LTR-based vectors suggested that PGE2-mediated activation effect on HIV-1
transcription was transduced via both NF-kappaB-dependent and -independent
signaling pathways. The involvement of NF-kappaB in the PGE2-dependent activating
effect on HIV-1 transcription was further confirmed using a kappaB-regulated
luciferase encoding vector and by electrophoretic mobility shift assays. Results
from Northern blot and flow cytometric analyses, as well as the use of a
selective antagonist indicated that PGE2 modulation of HIV-1 LTR-driven reporter
gene activity in studied T lymphoid cells is transduced via the EP4 receptor
subtype. These results suggest that secretion of PGE2 by macrophages in response
to infection or inflammatory activators could induce signaling events resulting
in activation of proviral DNA present into T cells latently infected with HIV-1.
PMID- 9765257
TI - Bacteriophage T7 DNA helicase binds dTTP, forms hexamers, and binds DNA in the
absence of Mg2+. The presence of dTTP is sufficient for hexamer formation and DNA
binding.
AB - The role of Mg2+ in dTTP hydrolysis, dTTP binding, hexamer formation, and DNA
binding was studied in bacteriophage T7 DNA helicase (4A' protein). The steady
state kcat for the dTTPase activity was 200-300-fold lower in the absence of
MgCl2, but the Km was only slightly affected. Direct dTTP binding experiments
showed that the Kd of dTTP was unaffected, but the stoichiometry of dTTP binding
was different in the absence of Mg2+. Two dTTPs were found to bind tightly in the
absence of Mg2+ in contrast to three to four in the presence of Mg2+. In the
presence of DNA there was little difference in the stoichiometry of dTTP binding
to 4A'. These results indicate that Mg2+ is not necessary for dTTP binding, but
Mg2+ is required for optimal hydrolysis of dTTP. Gel filtration of 4A' in the
presence of dTTP without Mg2+ showed that Mg2+ was not necessary, and dTTP was
sufficient for hexamer formation. The hexamers formed in the presence of dTTP
without Mg2+ were capable of binding single-stranded DNA. However, the 4A'
hexamers formed in the presence of dTDP with or without Mg2+ did not bind DNA,
indicating that hexamer formation itself is not sufficient for DNA binding. The
hexamers need to be in the correct conformation, in this case in the dTTP-bound
state, to interact with the DNA. Thus, the gamma-phosphate of dTTP plays an
important role in causing a conformational change in the protein that leads to
stable interactions of 4A' with the DNA.
PMID- 9765258
TI - Activation of protein kinase B/Akt is sufficient to repress the glucocorticoid
and cAMP induction of phosphoenolpyruvate carboxykinase gene.
AB - A rat hepatoma cell line, H4IIE, was stably transfected with a tamoxifen
regulatable Akt-1 construct. Treatment of these cells with tamoxifen caused a
rapid stimulation of Akt enzymatic activity that was comparable with the activity
observed with the endogenous Akt after insulin stimulation. Prior studies have
extensively documented that insulin can repress the glucocorticoid and cAMP
stimulated increase in phosphoenolpyruvate carboxykinase (PEPCK) gene
transcription. Activation of this regulatable Akt with tamoxifen was found to
mimic the dominant inhibitory effect of insulin on PEPCK gene transcription. Dose
response curves to insulin and tamoxifen demonstrated that this response was very
sensitive to Akt activation although the maximal response observed with tamoxifen
activation was slightly less than that observed with insulin, indicating that the
response to insulin may also involve other signaling cascades. The regulation of
PEPCK transcription via Akt was, like that previously described for insulin, not
dependent upon 70 kDa S6 kinase activity in that it was not inhibited by
rapamycin. Finally, the expression of a kinase dead Akt was able to partially
inhibit the ability of insulin to stimulate this response. In summary, the
present results indicate that activation of Akt alone is sufficient to repress
the glucocorticoid and cAMP-stimulated increase in PEPCK gene transcription.
PMID- 9765259
TI - The sulfuryl transfer mechanism. Crystal structure of a vanadate complex of
estrogen sulfotransferase and mutational analysis.
AB - Estrogen sulfotransferase (EST) catalyzes transfer of the 5'-sulfuryl group of
adenosine 3'-phosphate 5'-phosphosulfate (PAPS) to the 3alpha-phenol group of
estrogenic steroids such as estradiol (E2). The recent crystal structure of EST
adenosine 3', 5'-diphosphate (PAP)- E2 complex has revealed that residues Lys48,
Thr45, Thr51, Thr52, Lys106, His108, and Try240 are in position to play a
catalytic role in the sulfuryl transfer reaction of EST (Kakuta Y., Pedersen, L.
G., Carter, C. W., Negishi, M., and Pedersen, L. C. (1997) Nat. Struct. Biol. 4,
904-908). Mutation of Lys48, Lys106, or His108 nearly abolishes EST activity,
indicating that they play a critical role in catalysis. A present 2.2-A
resolution structure of EST-PAP-vanadate complex indicates that the vanadate
molecule adopts a trigonal bipyramidal geometry with its equatorial oxygens
coordinated to these three residues. The apical positions of the vanadate
molecule are occupied by a terminal oxygen of the 5'-phosphate of PAP (2.1 A) and
a possible water molecule (2. 3 A). This water molecule superimposes well to the
3alpha-phenol group of E2 in the crystal structure of the EST.PAP.E2 complex.
These structures are characteristic of the transition state for an in-line
sulfuryl transfer reaction from PAPS to E2. Moreover, residues Lys48, Lys106, and
His108 are found to be coordinated with the vanadate molecule at the transition
state of EST.
PMID- 9765260
TI - Transcription factor AP-2gamma regulates murine adenosine deaminase gene
expression during placental development.
AB - Trophoblast cells are specialized extra-embryonic cells present only in eutherian
mammals. They play a major role in the implantation and placentation processes.
To understand better the molecular mechanisms that control the development and
function of trophoblast cells, we sought to identify the transcription factors
that regulate murine adenosine deaminase (ADA) gene expression in the placenta.
Here we report a detailed characterization of a placenta-specific footprinting
region (FP1) in the Ada placental regulatory element. The sequence of FP1 was
mapped by DNase I footprinting and was found to match a consensus AP-2
transcription factor-binding site. Electrophoretic mobility shift assays
demonstrated that FP1 interacted with AP-2-like proteins. Further analysis using
AP-2 antibody confirmed that AP-2 protein was indeed present in the placenta and
bound to FP1. Mutation at the AP-2 site in FP1 abolished the ability of the Ada
placental regulatory element to bind AP-2 proteins and failed to target
chloramphenicol acetyltransferase reporter gene expression to placentas in
transgenic mice, indicating that AP-2 is required for Ada expression in the
placenta. In addition, RNase protection assays demonstrated that AP-2gamma was
the predominant AP-2 family member expressed in the placenta. In situ
hybridization analysis revealed that AP-2gamma expression was enriched in the
trophoblast lineage throughout development, suggesting that AP-2gamma may be
critical for trophoblast development and differentiation.
PMID- 9765261
TI - An extended alpha-helix and specific amino acid residues opposite the DNA-binding
surface of the cAMP response element binding protein basic domain are important
for human T cell lymphotropic retrovirus type I Tax binding.
AB - The human T cell lymphotropic retrovirus type I (HTLV-I) trans-activator, Tax,
interacts specifically with the basic-domain/leucine-zipper (bZip) protein, cAMP
response element binding protein (CREB), bound to the viral Tax-responsive
element consisting of three imperfect 21-base pair repeats, each with a cAMP
response element core flanked by G/C-rich sequences. Here, the minimal CREB-bZip
necessary for Tax binding is shown to be composed of amino acid residues 280-341.
The Tax-CREB interaction involves an uninterrupted and extended alpha-helix in
CREB that spans most of its basic domain to include amino acid residues localized
to the NH2 terminus of the DNA binding region. Mutational analyses indicate that
three residues, Arg284, Met291, and Glu299 unique to this region of the
CREB/activating transcription factor-1 subfamily of bZip proteins, constitute the
contact surface for Tax. Amino acid substitutions in these positions had little
impact on CREB-bZip binding to DNA but abrogated its binding to Tax. Each of the
contact residues for Tax are spaced approximately two helical turns apart on the
side of the bZip helix directly opposite to that of the invariant DNA-binding
residues. Molecular modeling reveals the Tax-contact residues to be near the
minor groove of the G/C-rich DNA in the 21-base pair repeat. They most likely
position Tax for minor groove contact with the G/C-rich sequences.
PMID- 9765262
TI - The gene glvA of Bacillus subtilis 168 encodes a metal-requiring, NAD(H)
dependent 6-phospho-alpha-glucosidase. Assignment to family 4 of the
glycosylhydrolase superfamily.
AB - The gene glvA (formerly glv-1) from Bacillus subtilis has been cloned and
expressed in Escherichia coli. The purified protein GlvA (449 residues, Mr =
50,513) is a unique 6-phosphoryl-O-alpha-D-glucopyranosyl:phosphoglucohydrolase
(6-phospho-alpha-glucosidase) that requires both NAD(H) and divalent metal (Mn2+,
Fe2+, Co2+, or Ni2+) for activity. 6-Phospho-alpha-glucosidase (EC 3.2.1.122)
from B. subtilis cross-reacts with polyclonal antibody to maltose 6-phosphate
hydrolase from Fusobacterium mortiferum, and the two proteins exhibit amino acid
sequence identity of 73%. Estimates for the Mr of GlvA determined by SDS
polyacrylamide gel electrophoresis (51,000) and electrospray-mass spectroscopy
(50,510) were in excellent agreement with the molecular weight of 50,513 deduced
from the amino acid sequence. The sequence of the first 37 residues from the N
terminus determined by automated analysis agreed precisely with that predicted by
translation of glvA. The chromogenic and fluorogenic substrates, p-nitrophenyl
alpha-D-glucopyranoside 6-phosphate and 4-methylumbelliferyl-alpha-D
glucopyranoside 6-phosphate were used for the discontinuous assay and in situ
detection of enzyme activity, respectively. Site-directed mutagenesis shows that
three acidic residues, Asp41, Glu111, and Glu359, are required for GlvA activity.
Asp41 is located at the C terminus of a betaalphabeta fold that may constitute
the dinucleotide binding domain of the protein. Glu111 and Glu359 may function as
the catalytic acid (proton donor) and nucleophile (base), respectively, during
hydrolysis of 6-phospho-alpha-glucoside substrates including maltose 6-phosphate
and trehalose 6-phosphate. In metal-free buffer, GlvA exists as an inactive
dimer, but in the presence of Mn2+ ion, these species associate to form the
NAD(H)-dependent catalytically active tetramer. By comparative sequence alignment
with its homologs, the novel 6-phospho-alpha-glucosidase from B. subtilis can be
assigned to the nine-member family 4 of the glycosylhydrolase superfamily.
PMID- 9765263
TI - Structure-based minimization of transforming growth factor-alpha (TGF-alpha)
through NMR analysis of the receptor-bound ligand. Design, solution structure,
and activity of TGF-alpha 8-50.
AB - The investigation of a N-terminally truncated human transforming growth factor
alpha (TGF-alpha; residues 8-50) has been completed to determine the contribution
of the N terminus to receptor binding and activation. The deletion protein was
proposed and designed through study of NMR relaxation and nuclear Overhauser
enhancement data obtained from the TGF-alpha-epidermal growth factor (EGF)
receptor complex, which indicated that the residues N-terminal to the A loop
remain flexible in receptor-bound TGF-alpha and thus suggested their lack of
involvement in receptor binding (Hoyt, D. W., Harkins, R. N., Debanne, M. T.,
O'Connor-McCourt, M., and Sykes, B. D. (1994) Biochemistry 33, 15283-15292;
McInnes, C., Hoyt, D. W., Harkins, R. N., Pagila, R. N., Debanne, M. T., O'Connor
McCourt, M., and Sykes, B. D. (1996) J. Biol. Chem. 271, 32204-32211). TGF-alpha
8-50 was shown to have approximately 10-fold lower affinity for the receptor than
the native molecule in an assay quantifying the ability to compete with EGF for
binding and to have a similar reduction in activity as indicated by a cell
proliferation assay. NMR solution structural calculations on this molecule
demonstrate correct formation of the three disulfide bonds of TGF-alpha 8-50 and
have established the presence of native secondary structure in the B and C loops
of the protein. However, some perturbation of the global fold with respect to the
orientation of the subdomains was observed. These results suggest that although
the N-terminal residues do not contribute directly to binding, they make a
significant contribution in defining the conformation of the growth factor, which
is required for complete binding and activity and is therefore significant in
terms of producing native folding of TGF-alpha. They also show that information
obtained from the receptor-bound ligand can be used to guide the design and
minimization of TGF-alpha analogues. The implications of the study of TGF-alpha 8
50 for the design and synthesis of reductants of this growth factor are therefore
discussed.
PMID- 9765264
TI - Definition and redesign of the extended substrate specificity of granzyme B.
AB - Granzyme B is a protease involved in the induction of rapid target cell death by
cytotoxic lymphocytes. Definition of the substrate specificity of granzyme B
allows for the identification of in vivo substrates in this process. By using the
combinatorial methods of synthetic substrate libraries and substrate-phage
display, an optimal substrate for granzyme B that spans over six subsites was
determined to be Ile-Glu-Xaa-(Asp downward arrowXaa)-Gly, with cleavage of the
Asp downward arrowXaa peptide bond. Granzyme B proteolysis was shown to be highly
dependent on the length and sequence of the substrate, supporting the role of
granzyme B as a regulatory protease. Arginine 192 was identified as a determinant
of P3-Glu and P1-Asp substrate specificity. Mutagenesis of arginine 192 to
glutamate reversed the preference for negatively charged amino acids at P3 to
positively charged amino acids. The preferred substrate sequence matches the
activation sites of caspase 3 and caspase 7 and thus is consistent with the role
of granzyme B in activation of these proteases during apoptosis. The caspase
substrate poly(ADP)-ribose polymerase is cleaved by granzyme B in a cell-free
assay at two sites that resemble the granzyme B specificity determined by the
combinatorial methods. Many caspase substrates contain granzyme B cleavage sites
and are proposed as potential granzyme B targets, suggesting a redundant function
with certain caspases.
PMID- 9765265
TI - Identification of protein-arginine N-methyltransferase as 10
formyltetrahydrofolate dehydrogenase.
AB - S-Adenosylmethionine:protein-arginine N-methyltransferase (EC 2.1.1. 23; protein
methylase I) transfers the methyl group of S-adenosyl-L-methionine to an arginine
residue of a protein substrate. The homogeneous liver protein methylase I was
subjected to tryptic digestion followed by reverse phase high performance liquid
chromatography (HPLC) separation and either "on-line" mass spectrometric
fragmentation or "off-line" Edman sequencing of selected fractions. Data base
searching of both the mass spectrometric and Edman sequencing data from several
peptides identified the protein methylase as 10-formyltetrahydrofolate
dehydrogenase (EC 1.5.1.6; Cook, R. J., Lloyd, R. S., and Wagner, C. (1991) J.
Biol. Chem. 266, 4965-4973; Swiss accession number). This identification was
confirmed by comparative HPLC tryptic peptide mapping and affinity chromatography
of the methylase on the 5-formyltetrahydrofolate-Sepharose affinity gel used to
purify the dehydrogenase. The purified rat liver methylase had approximately 33%
of the 10-formyltetrahydrofolate dehydrogenase and 36% of the aldehyde
dehydrogenase activity as compared with the recombinant dehydrogenase, which also
had protein methylase I activity. Polyclonal antibodies against recombinant
dehydrogenase reacted with protein methylase I purified either by polyacrylamide
gel electrophoresis or 5-formyltetrahydrofolate affinity chromatography. In each
instance there was only a single immunoreactive band at a molecular weight of
approximately 106,000. Together, these results confirm the co-identity of protein
arginine methyltransferase and 10-formyltetrahydrofolate dehydrogenase.
PMID- 9765266
TI - Receptor-regulated translocation of endothelial nitric-oxide synthase.
AB - The endothelial nitric-oxide synthase (eNOS) is activated by transient increases
in intracellular Ca2+ elicited by stimulation of diverse receptors, including
bradykinin B2 receptors on endothelial cells. eNOS and B2 receptors are targeted
to specialized signal-transducing domains in the plasma membrane termed
plasmalemmal caveolae. Targeting to caveolae facilitates eNOS activation
following receptor stimulation, but in resting cells, eNOS is tonically inhibited
by its interactions with caveolin, the scaffolding protein in caveolae. We used a
quantitative approach exploiting immunofluorescence microscopy to investigate
regulation of the subcellular distribution of eNOS in endothelial cells by
bradykinin and Ca2+. In resting cells, most of the eNOS is localized at the cell
membrane. However, within 5 min following addition of bradykinin, nearly all the
eNOS translocates to structures in the cell cytosol; following more protracted
incubations with bradykinin, most of the cytosolic enzyme subsequently
translocates back to the cell membrane. The bradykinin-induced internalization of
eNOS is completely abrogated by the intracellular Ca2+ chelator BAPTA;
conversely, Ca2+-mobilizing drugs and agonists promote eNOS translocation. These
results establish that eNOS targeting to the membrane is labile and is subject to
receptor-regulated Ca2+-dependent reversible translocation, providing another
point for regulation of NO-dependent signaling in the vascular endothelium.
PMID- 9765267
TI - Apoptosis and activation of the sphingomyelin-ceramide pathway induced by
oxidized low density lipoproteins are not causally related in ECV-304 endothelial
cells.
AB - Oxidized low density lipoproteins (oxLDL) are thought to play a central role in
the development of atherosclerosis. Toxic concentrations of mildly oxidized LDL
elicit massive apoptosis of endothelial cells (Escargueil-Blanc, I., Meilhac, O.,
Pieraggi, M. T. , Arnal J. F., Salvayre, R., Negre-Salvayre, A. (1997)
Arterioscler. Thromb. Vasc. Biol. 17, 331-339). Since the lipid mediator ceramide
emerged as a potent inducer of apoptosis, we aimed at investigating the
occurrence of ceramide formation and its potential role in oxLDL-induced
apoptosis. In ECV-304 endothelial cells, toxic concentrations of oxLDL triggered
an early activation of the sphingomyelin-ceramide pathway, as shown by both
sphingomyelin hydrolysis and ceramide formation. N-Tosyl-L-phenylalanyl
chloromethyl ketone (TPCK) and dichloroisocoumarin (DCIC), two serine-protease
inhibitors (serpins), blocked the oxLDL-induced ceramide generation but,
unexpectedly, did not inhibit the oxLDL-induced apoptosis. Conversely, treatment
of endothelial cells by bacterial sphingomyelinase, under conditions effectively
generating ceramide, did not induce apoptosis. In contrast, short-chain permeant
C2- and C6-ceramides elicited apoptosis of ECV-304. However, the mechanisms of
apoptosis triggered by C2-ceramide and by oxLDL were (at least in part)
different, because C2-ceramide-induced apoptosis was calcium-independent, whereas
oxLDL-induced apoptosis was calcium-dependent. In conclusion, it is suggested
that oxLDL-induced apoptosis is calcium-dependent but independent of the
activation of the sphingomyelin-ceramide pathway and that the toxic effect of
short chain permeant ceramides is calcium-independent and does not mimic the
effect of natural ceramides induced by oxLDL.
PMID- 9765268
TI - The I domain of integrin leukocyte function-associated antigen-1 is involved in a
conformational change leading to high affinity binding to ligand intercellular
adhesion molecule 1 (ICAM-1).
AB - On T cells the leukocyte integrin leukocyte function-associated antigen-1 (LFA-1)
(CD11a/CD18) can be induced to bind its ligand intercellular adhesion molecule 1
(ICAM-1) (CD54) either by increasing the affinity of the receptor with Mg2+ and
EGTA or by receptor clustering following activation with phorbol ester. The
existence of these two adhesion-inducing pathways implies that alternative
mechanisms might exist by which LFA-1 engages ICAM-1. The LFA-1 alpha subunit I
domain contains a major binding site for ICAM-1. In this study we show that
soluble LFA-1 I domain blocks ICAM-1 binding of the high affinity Mg2+-induced
form of LFA-1 but not the phorbol ester-induced form. Under conditions of Mg2+
activation, the soluble I domain also prevents expression of an activation
dependent epitope on LFA-1, implying that it inhibits a conformational change
necessary for conversion to the high affinity form of this integrin. In addition,
the binding of Mg2+-activated LFA-1 to ICAM-1 is blocked by peptides covering the
alpha4-beta3 loop, the beta3-alpha5 loop, and the alpha5 helix of the I domain,
whereas none of the peptides tested blocks phorbol ester-mediated adhesion. The
blocking peptides localize to the same face of the crystal structure of the LFA-1
I domain and define an area that, during activation, may be involved in
association of the I domain with another region of LFA-1, potentially the beta
propeller domain. This is the first evidence linking a structural domain of an
integrin, in this case the I domain, with a particular activation mechanism.
PMID- 9765269
TI - Effects of mutations in the gamma-phosphate binding site of myosin on its motor
function.
AB - The role of the highly conserved residues in the gamma-phosphate binding site of
myosin upon myosin motor function was studied. Each of five residues (Ser181,
Lys185, Asn235, Ser236, and Arg238) in smooth muscle myosin was mutated. K185Q
has neither a steady state ATPase nor an initial Pi burst. Although ATP and actin
bind to K185Q, it is not dissociated from actin by ATP. These results indicate
that the hydrolysis of bound ATP by K185Q is inhibited. S236T has nearly normal
basal Mg2+-ATPase activity, initial Pi burst, ATP-induced enhancement of
intrinsic tryptophan fluorescence, and ATP-induced dissociation from actin.
However, the actin activation of the Mg2+-ATPase activity and actin translocation
of S236T were blocked. In contrast S236A has nearly normal enzymatic properties
and actin-translocating activity. These results indicate that 1) the hydroxyl
group of Ser236 is not critical as an intermediary of proton transfer during the
ATP hydrolysis step, and 2) the bulk of the extra methyl group of the threonine
residue in S236T blocks the acceleration of product release from the active site
by actin. Arg238, which interacts with Glu459 at the Switch II region, was
mutated to Lys and Ile, respectively. R238K has essentially normal enzymatic
activity and motility. In contrast, R238I does not hydrolyze ATP or support
motility, although it still binds ATP. These results indicate that the charge
interaction between Glu459 and Arg238 is critical for ATP hydrolysis by myosin.
Other mutants, S181A, S181T, and N235I, showed nearly normal enzymatic and motile
activity.
PMID- 9765270
TI - AKAP79 inhibits calcineurin through a site distinct from the immunophilin-binding
region.
AB - Targeting of protein kinases and phosphatases provides additional specificity to
substrate selectivity in cellular signaling. In the case of the Ca2+/calmodulin
dependent protein phosphatase calcineurin, AKAP79 has been shown to bind
calcineurin and inhibit its activity in vitro (Coghlan, V., Perrino, B. A.,
Howard, M., Langeberg, L. K., Hicks, J. B., Gallatin, W. M., and Scott, J. D.
(1995) Science 267, 108-111). In the present study, we characterized the binding
regions on calcineurin A (CnA) and AKAP79 that are important for this
interaction. Residues 30-98 and 311-336 on CnA, and residues 108-280 on AKAP79
were found to be important for binding. The binding of CnA by AKAP79 does not
require the calcineurin B subunit, and occurs in a region distinct from where the
immunosuppressant-immunophilin complex bind. AKAP79 also bound to CnA in cells
transfected with AKAP79 and CnA. To determine the function of AKAP79-calcineurin
interaction in intact cells, we measured the dephosphorylation and subsequent
activation of NFAT, a transcription factor that is a substrate for calcineurin.
Overexpression of AKAP79 inhibited NFAT dephosphorylation, resulting in a
decrease in NFAT activation. These results demonstrated that AKAP79 can bind to
and inhibit calcineurin activity in vivo, suggesting a physiological role for
AKAP79-calcineurin interaction in NFAT-mediated signaling.
PMID- 9765271
TI - Characterization of the murine fatty acid transport protein gene and its insulin
response sequence.
AB - Fatty acid transport protein (FATP) was identified by expression cloning
strategies (Schaffer, J. E., and Lodish, H. F. (1994) Cell 79, 427-436) and shown
by transfection analysis to catalyze the transfer of long-chain fatty acids
across the plasma membrane of cells. It is expressed highly in tissues exhibiting
rapid fatty acid metabolism such as skeletal muscle, heart, and adipose. FATP
mRNA levels are down-regulated by insulin in cultured 3T3-L1 adipocytes and up
regulated by nutrient depletion in murine adipose tissue (Man, M. Z., Hui, T. Y.,
Schaffer, J. E., Lodish, H. F., and Bernlohr, D. A. (1996) Mol. Endocrinol. 10,
1021-1028). To determine the molecular mechanism of insulin regulation of FATP
transcription, we have isolated the murine FATP gene and its 5'-flanking
sequences. The FATP gene spans approximately 16 kilobases and contains 13 exons,
of which exon 2 is alternatively spliced. S1 nuclease and RNase protection assays
revealed the presence of multiple transcription start sites; the DNA sequence
upstream of the predominant transcription start sites lacks a typical TATA box.
By transient transfection assays in 3T3-L1 adipocytes, the inhibitory action of
insulin on FATP transcription was localized to a cis-acting element with the
sequence 5'-TGTTTTC-3' from -1347 to -1353. This sequence is very similar to the
insulin response sequence found in the regulatory region of other genes
negatively regulated by insulin such as those encoding phosphoenolpyruvate
carboxykinase, tyrosine aminotransferase, and insulin-like growth factor-binding
protein 1. Fluorescence in situ hybridization analysis revealed that the murine
FATP gene is localized to chromosome 8, band 8B3.3. Interestingly, this region of
chromosome 8 contains a cluster of three other genes important for fatty acid
homeostasis, lipoprotein lipase, the mitochondrial uncoupling protein 1 (UCP1)
and sterol regulatory element-binding protein 1. These results characterize the
murine FATP gene and its insulin responsiveness as well as present a framework
for future studies of its role in lipid metabolism, obesity, and type II diabetes
mellitus.
PMID- 9765272
TI - Calmodulin-dependent regulation of inducible and neuronal nitric-oxide synthase.
AB - Neuronal and endothelial nitric-oxide synthases depend upon Ca2+/calmodulin for
activation, whereas the activity of the inducible nitric-oxide synthase is Ca2+
independent, presumably due to tightly bound calmodulin. To study these different
mechanisms, a series of chimeras derived from neuronal and inducible nitric-
oxide synthases were analyzed. Chimeras containing only the oxygenase domain,
calmodulin-binding region, or reductase domain of inducible nitric-oxide synthase
did not confer significant Ca2+-independent activity. However, each chimera was
more sensitive to Ca2+ than the neuronal isoform. The calmodulin-binding region
of inducible nitric-oxide synthase with either its oxygenase or reductase domains
resulted in significant, but not total, Ca2+-independent activity. Co
immunoprecipitation experiments showed no calmodulin associated with the former
chimera in the absence of Ca2+. Trifluoperazine also inhibited this chimera in
the absence of Ca2+. The combined interactions of calmodulin bound to inducible
nitric-oxide synthase calmodulin-binding region with the oxygenase domain may be
weaker than with the reductase domain. Thus, Ca2+-independent activity of
inducible nitric-oxide synthase appears to result from the concerted interactions
of calmodulin with both the oxygenase and reductase domains in addition to the
canonical calmodulin-binding region. The neuronal isoform is not regulated by a
unique autoinhibitory element in its reductase domain.
PMID- 9765273
TI - The dependence of membrane permeability by the antibacterial peptide cecropin B
and its analogs, CB-1 and CB-3, on liposomes of different composition.
AB - A natural antibacterial peptide, cecropin B (CB), and designed analogs, CB-1 and
CB-3, were synthesized. The three peptides have different structural
characteristics, with CB having one hydrophobic and one amphipathic alpha-helix,
CB-1 having two amphipathic alpha-helices, and CB-3 having two hydrophobic alpha
helices. These differences were used as the rationale for a study of their
efficacy in breaking liposomes with different combinations of phosphatidic acid
and phosphatidylcholine. Biosensor binding measurements and encapsulating dye
leakage studies showed that the higher binding affinity of CB and CB-1 to the
polar heads of lipids is not necessary for the peptides to be more effective at
lysing lipid bilayers, especially when liposomes have a higher phosphatidic acid
content. Kinetic studies, by intrinsic and extrinsic fluorescence stopped-flow
measurements, revealed two transitional steps in liposome breakage by CB and CB
1, although only one kinetic step was found for CB-3. Circular dichroism stopped
flow measurements, monitoring the formation of secondary structure in the
peptides, found one kinetic step for the interaction of all of the peptides with
the liposomes. Also, the alpha-helical motif of the peptides was maintained after
interacting with the liposomes. Based on these results, the mechanisms of
liposome lysis by CB, CB-1, and CB-3 are discussed.
PMID- 9765274
TI - Amino acid residues in thrombin-sensitive region and first epidermal growth
factor domain of vitamin K-dependent protein S determining specificity of the
activated protein C cofactor function.
AB - Human protein S (PS) potentiates the anticoagulant activity of human but not
bovine activated protein C (APC), whereas bovine PS is a cofactor to APC from
both species. The structural requirements for the specificity of the APC cofactor
function of human PS are located in its thrombin-sensitive region (TSR) and the
first epidermal growth factor (EGF1)-like module. To elucidate which residues in
these two modules determine the specificity of the APC cofactor activity, 41
human PS mutants were expressed. All mutants were cofactors to human APC and some
also to bovine APC. Residues in TSR (positions 49 and 52) and EGF1 (residues 97
and 106) together determined the specificity of the APC cofactor function,
whereas substitution of individual residues did not change specificity. Bovine
PS, and mutants expressing cofactor activity to bovine APC, stimulated
phospholipid binding of bovine APC. In contrast, human PS and mutants lacking
cofactor activity to bovine APC failed to support binding of bovine APC to
phospholipids. These data indicate that residues in TSR and EGF1 cause the
specificity of the APC cofactor activity and support the concept that key
residues in these two modules interact with APC on the phospholipid surface.
PMID- 9765275
TI - The human WD repeat protein WAIT-1 specifically interacts with the cytoplasmic
tails of beta7-integrins.
AB - Integrins of the beta7 subfamily, alpha4 beta7 and alphaE beta7, contribute to
lymphocyte homing and to the development of protective or autoreactive immune
responses at mucosal sites. The beta subunits of integrins are considered
important for regulation of stimulated cell adhesion and adhesion-dependent
signal transduction. Using a yeast interaction trap screen, a human WD repeat
protein, termed WAIT-1, was isolated that interacts with the integrin beta7
cytoplasmic tail and is homologous to mouse EED and Drosophila ESC proteins. WAIT
1 also binds to the cytoplasmic domains of alpha4 and alphaE but not to those of
integrin beta1, beta2, and alphaL subunits. Association of WAIT-1 and beta7
integrin was confirmed by coprecipitation from transiently transfected 293 cells.
The binding site for WAIT-1 was mapped to a short membrane-proximal region of the
beta7 cytoplasmic tail with Tyr-735 being of critical importance. Northern blot
analysis revealed multiple WAIT-1-related transcripts with differential
expression in circulating leukocytes, tissue-resident cells of diverse origin,
and lymphoid malignancies. These results suggest that WAIT-1, together with the
recently identified RACK1, may define a novel subfamily of WD repeat proteins
that interact with distinct subsets of integrin cytoplasmic tails and may act as
specific regulators of integrin function.
PMID- 9765276
TI - Interleukin-17-induced gene expression in articular chondrocytes is associated
with activation of mitogen-activated protein kinases and NF-kappaB.
AB - This study examines intracellular signaling events associated with the activation
of chondrocytes by the cytokine interleukin-17 (IL-17). Stimulation of normal
human articular chondrocytes with IL-17 induced nitric oxide (NO) production,
concomitant with an increase in transcripts and de novo translation products of
the inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) genes.
Several other genes associated with inflammation and cartilage degradation, such
as IL-1beta, IL-6, and stromelysin, were also up-regulated in IL-17-treated
chondrocytes. Among signaling events displaying early response to IL-17 in
chondrocytes were the mitogen-activated protein (MAP) kinases ERK1, ERK2, JNK,
and p38. DNA binding activity of NF-kappaB was also significantly induced. IL-17
effects on NO release, as well as iNOS, COX-2, and IL-6 protein expression, were
inhibited by the anti-inflammatory drug dexamethasone. Importantly, dexamethasone
blunted IL-17-dependent activation of MAP kinases, suggesting a mechanistic
relationship between these activities and the aforementioned gene expression
responses. Similar effects of a lesser extent were observed with the p38-specific
inhibitor SB203580. These results suggest that IL-17 activation of chondrocytes
is associated with and depends at least in part on the activation of MAP kinases
and NF-kappaB.
PMID- 9765277
TI - Sp1 and Sp3 regulate transcriptional activity of the facilitative glucose
transporter isoform-3 gene in mammalian neuroblasts and trophoblasts.
AB - The murine facilitative glucose transporter isoform 3 (Glut 3) is developmentally
regulated and is predominantly expressed in neurons and trophoblasts. Employing
the primer extension and RNase protection assays, the transcription start site
(denoted as +1) of the murine Glut 3 gene was localized to 305 base pairs (bp) 5'
to the ATG translation start codon. Transient transfection assays in N2A, H19-7
neuroblasts, and HRP.1 trophoblasts using sequential 5'-deletions of the murine
Glut 3-luciferase fusion gene indicated that the -203 to +237 bp region with
reference to the transcriptional start site contained promoter activity.
Repressor function was limited to the -137 to -130 bp region within the
transcriptional activation domain. The nuclear factors Sp1 and Sp3 bound this GC
rich region in N2A, H19-7, and HRP.1 cells. Dephosphorylation of Sp1 was
essential for Glut 3 DNA binding. The related Sp3 protein also bound this same
region of mouse Glut 3 in all three cell lines. Mutations of the Sp1-binding site
employed in transient transfection and mobility shift assays confirmed the nature
of the DNA-binding proteins, while supershift assays with anti-Sp1 and anti-Sp3
IgGs characterized the differences in the two DNA-binding proteins. Co
transfection of the Glut 3-luciferase fusion gene with or without mutations of
the Sp1-binding site along with the Sp1 or Sp3 expression vectors in Drosophila
SL2 cells confirmed a reciprocal effect, with Sp1 suppressing and Sp3 activating
Glut 3 gene transcription.
PMID- 9765279
TI - Replication protein A stimulates long patch DNA base excision repair.
AB - Two pathways for completion of DNA base excision repair (BER) have recently
emerged. In one, called short patch BER, only the damaged nucleotide is replaced,
whereas in the second, known as long patch BER, the monobasic lesion is removed
along with additional downstream nucleotides. Flap endonuclease 1, which
preferentially cleaves unannealed 5'-flap structures in DNA, has been shown to
play a crucial role in the long patch mode of repair. This nuclease will
efficiently release 5'-terminal abasic lesions as part of an intact
oligonucleotide when cleavage is combined with strand displacement synthesis.
Further gap filling and ligation complete repair. We reconstituted the final
steps of long patch base excision repair in vitro using calf DNA polymerase
epsilon to provide strand displacement synthesis, human flap endonuclease 1, and
human DNA ligase I. Replication protein A is an important constituent of the DNA
replication machinery. It also has been shown to interact with an early component
of base excision repair: uracil glycosylase. Here we show that human replication
protein A greatly stimulates long patch base excision repair.
PMID- 9765278
TI - Cyclic GMP and cGMP-binding phosphodiesterase are required for interleukin-1
induced nitric oxide synthesis in human articular chondrocytes.
AB - This study addressed the role of guanylyl cyclase (GC) and phosphodiesterase
(PDE) in interleukin (IL)-1 activation of human articular chondrocytes. The GC
inhibitors LY83583 and methylene blue dose-dependently inhibited IL-1-induced
nitric oxide (NO) production, inducible NO synthase (iNOS) protein, and mRNA
expression. These effects of GC inhibition were consistent with the rapid
induction of cGMP by IL-1, which reached maximal levels after 5 min. The effects
of GC inhibitors were selective as they did not reduce IL-1-induced
cyclooxygenase II protein and mRNA. An inhibitor specific for soluble GC did not
affect IL-1-induced NO production, and activators of soluble GC did not induce
NO. However, the expression of iNOS mRNA was induced by atrial natriuretic
peptide (ANP) and C-type natriuretic peptide (CNP), activators of particulate GC,
indicating that particulate rather than soluble guanylyl cyclases were involved
in iNOS induction. The expression of iNOS mRNA and the production of NO were
induced by a slowly hydrolyzable analog of cGMP, 8-bromo-cGMP, but not by
nonhydrolyzable analog, dibutyryl cGMP, suggesting that PDE rather than cGMP
dependent protein kinase mediates the cGMP effects. Chondrocytes contained
extensive cGMP PDE activity. This had PDE5 biochemical features and an inhibitor
profile consistent with PDE5. Furthermore, the nonisoformspecific PDE inhibitor
IBMX and PDE5-specific inhibitors suppressed IL-1-induced NO release and iNOS
mRNA expression. PDE5 mRNA was constitutively expressed in chondrocytes. In
addition to increasing PDE5 activities, IL-1 treatment reduced the sensitivity of
PDE5 to several pharmacological inhibitors by up to 50-fold. In summary,
inhibitors of either GC or PDE5 prevented IL-1 induction of iNOS; IL-1 increased
the rates of both cGMP generation and hydrolysis; and exogenous PDE hydrolyzable
cGMP analog induced iNOS and NO. These results suggest that increased cGMP
metabolic flux is sufficient to induce iNOS, and GC and PDE5 activities are
required for IL-1 induction of iNOS expression via increases in coupled cGMP
synthesis and hydrolysis.
PMID- 9765280
TI - Identification of native atrial G-protein-regulated inwardly rectifying K+
(GIRK4) channel homomultimers.
AB - G-protein-regulated inwardly rectifying K+ (GIRK) channels play critical
inhibitory roles throughout the nervous system, heart, and pancreas. They are
believed to be heterotetramers consisting of GIRK1 (Kir3.1) and either GIRK2
(Kir3.2), GIRK3 (Kir3.3), or GIRK4 (Kir3.4) subunits. The GIRK1 subunit is
hypothesized to be critical to form GIRK channels with normal channel kinetics
based on heterologous expression studies. However, GIRK2 and GIRK3 proteins are
present in areas of the brain where no GIRK1 has been detected. Here we
demonstrate that GIRK tetramers lacking GIRK1 can be purified from bovine heart
atria. We have found that only half of GIRK4 is purified as the GIRK1-GIRK4
heterotetramer, whereas the remaining GIRK4 forms a high molecular weight, SDS
resistant complex that does not contain GIRK1. These GIRK4 complexes, most likely
GIRK4 homotetramers, were previously not seen because of their aberrant migration
on SDS-polyacrylamide gels. We propose that all of GIRK1 and half of GIRK4
proteins in atria combine to form the heterotetramer IKACh, whereas the remaining
GIRK4 forms a novel tetrameric complex. GIRK4 homotetramers form channels with
unusual single channel behavior, and their contribution to native currents
requires further investigation.
PMID- 9765281
TI - Hypoglycemia-associated hyperammonemia caused by impaired expression of ornithine
cycle enzyme genes in C/EBPalpha knockout mice.
AB - Ammonia produced by amino acid metabolism is detoxified through conversion into
urea by the ornithine cycle in the liver, whereas carbon skeletons of amino acids
are converted to glucose by gluconeogenic enzymes. Promoter and enhancer
sequences of several genes for ornithine cycle enzymes interact with members of
the CCAAT/enhancer-binding protein (C/EBP) transcription factor family.
Disruption of the C/EBPalpha gene in mice causes hypoglycemia associated with the
impaired expression of gluconeogenic enzymes. Here we examined the expression of
ornithine cycle enzyme genes in the livers of C/EBPalpha-deficient mice. mRNA
levels for the first, third, fourth, and fifth enzymes of five enzymes in the
cycle were decreased in C/EBPalpha-deficient mice. Protein levels for the first,
second, fourth, and fifth enzymes were also decreased. In situ hybridization
analysis revealed that the enzyme mRNAs were distributed normally in the
periportal region but were disordered in C/EBPalpha-deficient mice with
relatively higher mRNA levels in the midlobular region. Blood ammonia
concentrations in the mutant mice were severalfold higher than in wild-type mice.
Thus, C/EBPalpha is crucial for ammonia detoxification by ornithine cycle enzymes
and for coordination of gluconeogenesis and urea synthesis.
PMID- 9765282
TI - Bone morphogenetic protein-1 processes the NH2-terminal propeptide, and a furin
like proprotein convertase processes the COOH-terminal propeptide of pro
alpha1(V) collagen.
AB - Bone morphogenetic protein-1 (BMP-1) plays key roles in regulating the deposition
of vertebrate extracellular matrix; it is the procollagen C-proteinase that
processes the major fibrillar collagen types I-III, and it may process prolysyl
oxidase to the mature enzyme necessary to the formation of covalent cross-links
in collagen and elastic fibers. Type V collagen is a fibrillar collagen of low
abundance that is incorporated into and helps regulate the shape and diameter of
type I collagen fibrils. Here we show that, in contrast to its action on
procollagens I-III, BMP-1 does not cleave the C-propeptide of pro-alpha1(V)
homotrimers. Instead, the single BMP-1-specific cleavage site within pro
alpha1(V) chains, lies within the large globular N-propeptide. This cleavage site
is immediately upstream of a glutamine, thus redefining the specificity of
cleavage for BMP-1-like enzymes. It also produces an NH2 terminus that
corresponds to an equivalent NH2 terminus on the processed matrix form of the
similar alpha1(XI) chain, thus suggesting physiological significance. Cleavage of
the C-propeptide occurs efficiently in recombinant pro-alpha1(V) homotrimers
produced in 293-EBNA human embryonic kidney cells, and this cleavage is shown to
occur immediately downstream of the sequence RTRR. This is similar to sites
cleaved by subtilisin-like proprotein/prohormone convertases and is shown to be
specifically cleaved by the recombinant subtilisin-like proprotein/prohormone
convertase furin.
PMID- 9765283
TI - SLP-76 is a direct substrate of SHP-1 recruited to killer cell inhibitory
receptors.
AB - Activation of immune system cells via antigen-, Fc-, or natural killer cell
triggering-receptor stimulation is aborted by co-engagement of inhibitory
receptors. Negative signaling by killer cell inhibitory receptors and related
receptors depends on the Src homology 2 (SH2)-containing protein tyrosine
phosphatase SHP-1. Using a combination of direct binding and functional assays,
we demonstrated that the SH2 domain-containing leukocyte protein 76 (SLP-76) is a
specific target for dephosphorylation by SHP-1 in T cells and natural killer
cells. Furthermore, we showed that tyrosine-phosphorylated SLP-76 is required for
optimal activation of cytotoxic lymphocytes, suggesting that the targeted
dephosphorylation of SLP-76 by SHP-1 is an important mechanism for the negative
regulation of immune cell activation by inhibitory receptors.
PMID- 9765284
TI - A vaccinia virus late transcription factor with biochemical and molecular
identity to a human cellular protein.
AB - A factor designated VLTF-X is required to support vaccinia virus late
transcription in vitro. It has been found that a late promoter DNA binding
activity cochromatographs and cosediments with VLTF-X activity. Current
experiments show that VLTF-X activity is present in a variety of uninfected
mammalian cell types and is indistinguishable from that recovered from infected
cells based upon several criteria. VLTF-X activity from both sources displays the
same purification profile over phosphocellulose and DNA affinity resins and has
the same sedimentation coefficient. In addition, the factors purified from both
infected and uninfected cells form protein-DNA complexes of identical
electrophoretic mobility in the presence of vaccinia virus late promoter
containing DNA. The affinity of these factors for the late promoter probes is
identical and late promoter-specific based on competition experiments. Moreover,
VLTF-X purified from both sources bound to late promoter-containing DNA in the
presence or absence of MgCl2 and ATP and formed complexes resistant to heat
inactivation. These experiments offer proof that vaccinia virus factor VLTF-X is
a host cell protein that supports transcription of the viral late genes.
PMID- 9765285
TI - DNA binding and transactivation characteristics of the mosquito ecdysone receptor
Ultraspiracle complex.
AB - The steroid hormone 20-hydroxyecdysone is a key regulatory factor, controlling
blood-meal triggered egg maturation in mosquitoes. To elucidate the ecdysone
hierarchy governing this event, we cloned and characterized the ecdysone receptor
(AaEcR) and the nuclear receptor Ultraspiracle (AaUSP), a retinoid X receptor
homologue, from the mosquito, Aedes aegypti, which form a functional complex
capable of ligand and DNA binding. Here we analyzed the DNA-binding properties of
the AaEcR.AaUSP heterodimer with respect to the effects of nucleotide sequence,
orientation, and spacing between half-sites in natural Drosophila and synthetic
ecdysone response element (EcREs). By using an electrophoretic gel mobility shift
assay, we showed that AaEcR.AaUSP exhibits a broad binding specificity, forming
complexes with inverted (IR) and direct (DR) repeats of the nuclear receptor
response element half-site consensus sequence AGGTCA separated by spacers of
variable length. A single nucleotide spacer was optimal for both imperfect (IRhsp
1) and perfect (IRper-1) inverted repeats; adding or removing 1 base pair in an
IRhsp-1 spacer practically abolished binding. However, changing the half-site to
the consensus sequence AGGTCA (IRper-1) increased binding of AaEcR.AaUSP 10-fold
over IRhsp-1 and, at the same time, reduced the stringency of the spacer length
requirement, with IRper-0 to IRper-5 showing detectable binding. Spacer length
was less important in DRs of AGGTCA (DR-0 to DR-5); although 4 bp was optimal, DR
3 and DR-5 bound AaEcR.AaUSP almost as efficiently as DR-4. Furthermore, AaEcR.
AaUSP also bound DRs separated by 11-13 nucleotide spacers. Competition
experiments and direct estimation of binding affinity (Kd) indicated that, given
identical consensus half-sites and an optimal spacer, the AaEcR.AaUSP heterodimer
bound an IR with higher affinity than a DR. Co-transfection assays utilizing CV-1
cells demonstrated that the mosquito EcR.USP heterodimer is capable of
transactivating reporter constructs containing either IR-1 or DR-4. The levels of
transactivation are correlated with the respective binding affinities of the
response elements (IRper-1 > DR-4 > IRhsp-1). Taken together, these analyses
predict broad variability in the EcREs of mosquito ecdysone-responsive genes.
PMID- 9765286
TI - Role of GHF-1 in the regulation of the rat growth hormone gene promoter by
thyroid hormone and retinoic acid receptors.
AB - In non-pituitary HeLa cells the unliganded thyroid hormone or retinoic acid
receptors cause a strong activation of the rat growth hormone promoter that is
repressed by their ligands. In contrast, after expression of the pituitary
specific transcription factor GHF-1, thyroid hormone and retinoic acid produce a
stimulation similar to that found in pituitary cells. Therefore, GHF-1 changes a
ligand-dependent inhibition into a ligand-dependent activation. The essential
role of GHF-1 on the rat growth hormone promoter was also demonstrated with AF-2
defective T3 receptor mutants that show a normal activation of this promoter in
the presence of GHF-1. Furthermore, a truncated T3 receptor, which lacks the N
terminus and the DNA binding domain, was able to stimulate this promoter in the
presence of GHF-1 and exogenous RXR receptors, suggesting the importance of
protein to protein interactions in this regulation. This study shows that the
final transcriptional effect depends not only on the type of regulatory promoter
response elements but also on the presence of other transcriptional activators,
in the case of the growth hormone promoter, the tissue-specific transcription
factor GHF-1, which plays a coactivator-like role in this promoter.
PMID- 9765288
TI - Secondary structure composition and pH-dependent conformational changes of
soluble recombinant HLA-DM.
AB - HLA-DM catalyzes the release of invariant chain fragments from newly synthesized
major histocompatibility complex (MHC) class II molecules, stabilizes empty class
II molecules, and edits class II-associated peptides by preferentially releasing
those that are loosely bound. The ability of HLA-DM to carry out these functions
in vitro is pH dependent, with an optimum at pH 4.5-5.5 and poor activity at pH
7. The structural basis for these properties of HLA-DM is unknown. Sequence
homology suggests that HLA-DM resembles classical, peptide-binding MHC class II
molecules. In this study, we examined whether HLA-DM has a secondary structure
composition consistent with an MHC fold and whether HLA-DM changes conformation
between pH 5 and pH 7. Far-UV circular dichroism (CD) spectra of recombinant
soluble HLA-DM (sDM) indicate that HLA-DM belongs to the alpha/beta class of
proteins and structurally resembles both MHC class I and class II molecules. The
CD peak around 198 nm increases upon going from neutral to endosomal pH and drops
sharply upon denaturation below pH 3.5, distinguishing at least three states of
sDM: the denatured state and two highly similar folded states. Fluorescence
emission spectra show a slight blue-shift and a approximately 20% drop in
intensity at pH 5 compared with pH 7. Unfolding experiments using guanidinium
chloride show that the stability of sDM is somewhat reduced but not lost at pH 5.
These results indicate that sDM undergoes a pH-dependent conformational change
between neutral and endosomal pH. The change seems to involve both hydrogen
bonding patterns and the hydrophobic core of sDM and may contribute to the pH
dependence of DM activity.
PMID- 9765287
TI - Herpesvirus entry mediator ligand (HVEM-L), a novel ligand for HVEM/TR2,
stimulates proliferation of T cells and inhibits HT29 cell growth.
AB - Herpesvirus entry mediator (HVEM), a member of the tumor necrosis factor (TNF)
receptor family, mediates herpesvirus entry into cells during infection. Upon
overexpression, HVEM activates NF-kappaB and AP-1 through a TNF receptor
associated factor (TRAF)-mediated mechanism. Using an HVEM-Fc fusion protein, we
screened soluble forms of novel TNF-related proteins derived from an expressed
sequence tag data base. One of these, which we designated HVEM-L, specifically
bound to HVEM-Fc with an affinity of 44 nM. This association was confirmed with
soluble and membrane forms of both receptor and ligand. HVEM-L mRNA is expressed
in spleen, lymph nodes, macrophages, and T cells and encodes a 240-amino acid
protein. A soluble, secreted form of the protein stimulates proliferation of T
lymphocytes during allogeneic responses, inhibits HT-29 cell growth, and weakly
stimulates NF-kappaB-dependent transcription.
PMID- 9765289
TI - Aquaporins in Saccharomyces. Genetic and functional distinctions between
laboratory and wild-type strains.
AB - Aquaporin water channel proteins mediate the transport of water across cell
membranes in numerous species. The Saccharomyces genome data base contains an
open reading frame (here designated AQY1) that encodes a protein with strong
homology to aquaporins. AQY1 from laboratory and wild-type strains of
Saccharomyces were expressed in Xenopus oocytes to determine the coefficients of
osmotic water permeability (Pf). Oocytes injected with wild-type AQY1 cRNAs
exhibit high Pf values, whereas oocytes injected with AQY1 cRNAs from laboratory
strains exhibit low Pf values and have reduced levels of Aqy1p due to two amino
acid substitutions. When the AQY1 gene was deleted from a wild-type yeast and
cells were cultured in vitro with cycled hypo-osmolar or hyper-osmolar stresses,
the AQY1 null yeast showed significantly improved viability when compared with
the parental wild-type strain. We conclude that Saccharomyces cerevisiae contains
at least one aquaporin gene, but it is not functional in laboratory strains due
to apparent negative selection pressures resulting from in vitro methods.
PMID- 9765290
TI - Characterization of the ATP- and GTP-specific succinyl-CoA synthetases in pigeon.
The enzymes incorporate the same alpha-subunit.
AB - Two succinyl-CoA synthetases, one highly specific for GTP/GDP and the other for
ATP/ADP, have been purified to homogeneity from pigeon liver and breast muscle.
The two enzymes are differentially distributed in pigeon, with only the GTP
specific enzyme detected in liver and the ATP-specific enzyme in breast muscle.
Based on assays in the direction of CoA formation, the ratios of GTP-specific to
ATP-specific activities in kidney, brain, and heart are approximately 7, 1, and
0.1, respectively. Both enzymes have the characteristic alpha- and beta-subunits
found in other succinyl-CoA synthetases. Studies of the alpha-subunit by
electrophoresis, mass spectrometry, reversed-phase high performance liquid
chromatography, and peptide mapping showed that it was the same in the two
enzymes. Characterization of the beta-subunits by the same methods indicated that
they were different, with the tryptic peptide maps providing evidence that the
beta-subunits likely differ along their entire sequences. Because the two
succinyl-CoA synthetases incorporate the same alpha-subunit, the determinants of
nucleotide specificity must reside within the beta-subunit. Determination of the
apparent Michaelis constants showed that the affinity of the GTP-specific enzyme
for GDP is greater than that of the ATP-specific enzyme for ADP (7 versus 250
microM). Rather large differences in apparent Km values were also observed for
succinate and phosphate.
PMID- 9765291
TI - Genetic evidence for the expression of ATP- and GTP-specific succinyl-CoA
synthetases in multicellular eucaryotes.
AB - Highly ATP- and GTP-specific isoforms of succinyl-CoA synthetase in pigeon
incorporate the same alpha-subunit, but different beta-subunits (Johnson, J. D.,
Muhonen, W. W., and Lambeth, D. O. (1998) J. Biol. Chem. 273, 27573-27579). The
sequences of the mature subunits were determined by methods based on reverse
transcription-polymerase chain reaction. The 306-residue mature alpha-subunit in
pigeon shows >88% identity to its homologues in pig and rat. The sequences of the
mature ATP- and GTP-specific beta-subunits (A-beta and G-beta, respectively) in
pigeon are 54% identical. These sequences were used to identify expressed
sequence tags for human and mouse that were highly homologous to G-beta and A
beta, respectively. The sequences for mature A-beta and G-beta in mouse and human
were completed and verified by polymerase chain reaction. The sequence of A-beta
in pig was also obtained. The mammalian A-beta sequences show >89% identity to
each other; the G-beta sequences are similarly related. However, pairwise
comparisons of the A-beta and G-beta sequences revealed <53% identity. Alignment
with two sequences of the beta-subunit in Caenorhabditis elegans suggests that
the A-beta and G-beta genes arose by duplication early in the evolution of
multicellular eucaryotes. The expression of A-beta is strong in numerous mouse
and human tissues, which suggests that ATP-specific succinyl-CoA synthetase also
plays an important role in species throughout the animal kingdom.
PMID- 9765292
TI - The Bloom's syndrome helicase unwinds G4 DNA.
AB - BLM, the gene that is defective in Bloom's syndrome, encodes a protein homologous
to RecQ subfamily helicases that functions as a 3'-5' DNA helicase in vitro. We
now report that the BLM helicase can unwind G4 DNA. The BLM G4 DNA unwinding
activity is ATP-dependent and requires a short 3' region of single-stranded DNA.
Strikingly, G4 DNA is a preferred substrate of the BLM helicase, as measured both
by efficiency of unwinding and by competition. These results suggest that G4 DNA
may be a natural substrate of BLM in vivo and that the failure to unwind G4 DNA
may cause the genomic instability and increased frequency of sister chromatid
exchange characteristic of Bloom's syndrome.
PMID- 9765293
TI - FCP1, the RAP74-interacting subunit of a human protein phosphatase that
dephosphorylates the carboxyl-terminal domain of RNA polymerase IIO.
AB - TFIIF (RAP30/74) is a general initiation factor that also increases the rate of
elongation by RNA polymerase II. A two-hybrid screen for RAP74-interacting
proteins produced cDNAs encoding FCP1a, a novel, ubiquitously expressed human
protein that interacts with the carboxyl-terminal evolutionarily conserved domain
of RAP74. Related cDNAs encoding FCP1b lack a carboxyl-terminal RAP74-binding
domain of FCP1a. FCP1 is an essential subunit of a RAP74-stimulated phosphatase
that processively dephosphorylates the carboxyl-terminal domain of the largest
RNA polymerase II subunit. FCP1 is also a stoichiometric component of a human RNA
polymerase II holoenzyme complex.
PMID- 9765294
TI - Dynamics of histone acetylation in Chlamydomonas reinhardtii.
AB - The dynamic character of core histone post-translational acetylation in the
unicellular green alga Chlamydomonas reinhardtii was studied by tritiated acetate
incorporation. Histone H3 is the major target of acetylation, steady state, and
in pulse and pulse-chase analyses. Acetylation turnover rates were measured by
tracer labeling under steady-state conditions. Half-lives of 1.5-3 min were found
for penta- to mono-acetylation of H3, dynamically acetylated to the 30% level.
Twenty percent of H3 was multi-acetylated, on average with 3. 2 acetyl-lysines,
all with rapid turnover. Deacetylase inhibitor trichostatin A (TSA) caused
doubling of average acetylation levels, primarily as penta-acetylated H3, but
half of H3 was not acetylated at all. The level of histone H4 acetylation was
only half that of H3 and a major fraction of mono- and di-acetylated forms
appeared static. The dynamic fraction had an average half-life of 3.5 min with
higher turnover rates for more highly acetylated H4 forms. TSA, inhibiting less
effectively deacetylases active on H4, strongly increased multi-acetylated H4
levels and doubled average acetylation. As for H3, half of histone H4 remained
unacetylated. Acetylation of histone H2B was low and of H2A was barely
measurable. Despite turnover with half-lives of approximately 2 min, no increase
beyond di-acetylation was seen upon TSA treatment.
PMID- 9765295
TI - Fcgamma receptor-mediated mitogen-activated protein kinase activation in
monocytes is independent of Ras.
AB - Receptors for the Fc portion of immunoglobulin molecules (FcR) present on
leukocyte cell membranes mediate a large number of cellular responses that are
very important in host defense, including phagocytosis, cell cytotoxicity,
production and secretion of inflammatory mediators, and modulation of the immune
response. Cross-linking of FcR with immune complexes leads, first to activation
of protein-tyrosine kinases. The molecular events that follow and that transduce
signals from these receptors to the nucleus are still poorly defined. We have
investigated the signal transduction pathway from Fc receptors that leads to gene
activation and production of cytokines in monocytes. Cross-linking of FcR, on the
THP-1 monocytic cell line, by immune complexes resulted in both activation of the
transcription factor NF-kappaB and interleukin 1 production. These responses were
completely blocked by tyrosine kinase inhibitors. In contrast, expression of
dominant negative mutants of Ras and Raf-1, in these cells, did not have any
effect on FcR-mediated nuclear factor activation, suggesting that the mitogen
activated protein kinase (MAPK) signaling pathway was not used by these
receptors. However, MAPK activation was easily detected by in vitro kinase
assays, after FcR cross-linking with immune complexes. Using the specific
MAPK/extracellular signal-regulated kinase kinase (MAPK kinase) inhibitor
PD98059, we found that MAPK activation is necessary for FcR-dependent activation
of the nuclear factor NF-kappaB. These results strongly suggest that the
signaling pathway from Fc receptors leading to expression of different genes
important to leukocyte biology, initiates with tyrosine kinases and requires MAPK
activation; but in contrast to other tyrosine kinase receptors, FcR-mediated MAPK
activation does not involve Ras and Raf.
PMID- 9765296
TI - Brain-derived neurotrophic factor induces rapid and transient release of
glutamate through the non-exocytotic pathway from cortical neurons.
AB - There is increasing interest in the involvement of neurotrophins in neural
transmission and plasticity. Thus, we investigated the effects of brain-derived
neurotrophic factor (BDNF) on glutamate release from cortical neurons. Treatment
of cultured cortical neurons with BDNF induced rapid and transient release of
glutamate. This effect was suggested to be mediated by TrkB activation because
K252a inhibited the release of glutamate and BDNF phosphorylated TrkB within 30
s. BDNF-induced glutamate release was observed even when using Ca2+-free assay
buffer but was inhibited by BAPTA-AM, a cell-permeable Ca2+ chelator. Therefore,
BDNF-induced glutamate release was independent of extracelluar Ca2+ but dependent
on intracellular Ca2+. Because normal neurotransmitter release is exocytotic, the
involvement of the exocytotic pathway in BDNF-induced glutamate release was
examined. As botulinum toxin is known to cleave exocytosis-associated proteins,
thereby inhibiting exocytosis, it was applied to neurons prior to the release
assay. Although botulinum toxin B cleaved VAMP2 and inhibited Ca2+-triggered
glutamate release, it did not inhibit the BDNF-induced release of glutamate.
These results strongly suggested that BDNF induces rapid and transient release of
glutamate from cortical neurons through a non-exocytotic pathway.
PMID- 9765297
TI - Purification and characterization of UDP-GlcNAc:Galbeta1-4GlcNAcbeta1-3*Galbeta1
4Glc(NAc)-R(GlcNAc to *Gal) beta1,6N-acetylglucosaminyltransferase from hog small
intestine.
AB - A beta1,6N-acetylglucosaminyltransferase (beta1-6GnT) responsible for the
formation of the beta1,6-branched poly-N-acetyllactosamine structure has been
purified 210,000-fold in 2.4% yield from a homogenate of hog small intestine by
successive column chromatographies involving CM-Sepharose FF, Ni2+-chelating
Sepharose FF, and UDP-hexanolamine-agarose, using an assay wherein
pyridylaminated lacto-N-neotetraose (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc-PA) was
used as an acceptor substrate, and the reaction product was Galbeta1-4GlcNAcbeta1
3(GlcNAcbeta1-6)Galbeta1-4 Glc-PA. The apparent molecular weight of the purified
enzyme was 76,000 under nonreducing conditions. The enzyme has a pH optimum at
7.0 and has no requirement for any divalent metal ions. The Km values for
pyridylaminated lacto-N-neotetraose and UDP-GlcNAc were 0.96 and 2. 59 mM,
respectively. For its activity, this enzyme was shown to have an absolute
requirement of at least a complete LacNAc (LacNAc = Galbeta1-4GlcNAc) residue
bound to position 3 of the acceptor Gal residues, i.e. it is capable of acting
only on the Gal residues of internal LacNAc units. The data strongly suggest that
this enzyme could be involved in generating branches to central positions of
preformed as well as growing polylactosamine chains, but not in synthesizing the
distal branches to growing polylactosamine chains.
PMID- 9765298
TI - The centrally acting beta1,6N-acetylglucosaminyltransferase (GlcNAc to gal).
Functional expression, purification, and acceptor specificity of a human enzyme
involved in midchain branching of linear poly-N-acetyllactosamines.
AB - In the present experiments the cDNA coding for a truncated form of the beta1,6N
acetylglucosaminyltransferase responsible for the conversion of linear to
branched polylactosamines in human PA1 cells was expressed in Sf9 insect cells.
The catalytic ectodomain of the enzyme was fused to glutathione S-transferase,
allowing effective one-step purification of the glycosylated 67-74-kDa fusion
protein. Typically a yield of 750 microg of the purified protein/liter of
suspension culture was obtained. The purified recombinant protein catalyzed the
transfer of GlcNAc from UDP-GlcNAc to the linear tetrasaccharide Galbeta1
4GlcNAcbeta1-3Galbeta1-4GlcNAc, converting the acceptor to the branched
pentasaccharide Galbeta1-4GlcNAcbeta1-3(GlcNAcbeta1-6)Galbeta1-4 GlcNAc as shown
by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,
degradative experiments, and 1H NMR spectroscopy of the product. By contrast, the
recombinant enzyme did not catalyze any reaction when incubated with UDP-GlcNAc
and the trisaccharide GlcNAcbeta1-3Galbeta1-4GlcNAc. Accordingly, we call the
recombinant beta1,6-GlcNAc transferase cIGnT6 to emphasize its action at central
rather than peridistal galactose residues of linear polylactosamines in the
biosynthesis of blood group I antigens. Taken together this in vitro expression
of I-branching enzyme, in combination with the previously cloned enzymes,
beta1,4galactosyltransferase and beta1, 3N-acetylglucosaminyltransferase, should
allow the general synthesis of polylactosamines based totally on the use of
recombinant enzymes.
PMID- 9765299
TI - Amyloid beta-peptide possesses a transforming growth factor-beta activity.
AB - Amyloid beta-peptide (Abeta) of 39-42 amino acid residues is a major constituent
of Alzheimer's disease neurite plaques. Abeta aggregates (fibrils) are believed
to be responsible for neuronal damage and dysfunction, as well as microglia and
astrocyte activation in disease lesions by multiple mechanisms. Since Abeta
aggregates possess the multiple valencies of an FAED motif (20th to 23rd amino
acid residues), which resembles the putative transforming growth factor-beta (TGF
beta) active site motif, we hypothesize that Abeta monomers and Abeta aggregates
may function as TGF-beta antagonists and partial agonists, analogous to
previously described monovalent and multivalent TGF-beta peptide antagonists and
agonists (Huang, S. S., Liu, Q., Johnson, F. E., Konish, Y., and Huang, J. S.
(1997) J. Biol. Chem. 272, 27155-27159). Here, we report that the Abeta monomer,
Abeta-(1-40) and its fragment, containing the motif inhibit radiolabeled TGF-beta
binding to cell-surface TGF-beta receptors in mink lung epithelial cells (Mv1Lu
cells). Abeta-(1-40)-bovine serum albumin conjugate (Abeta-(1-40)-BSA), a
multivalent synthetic analogue of Abeta aggregates, exhibited cytotoxicity toward
bovine cerebral endothelial cells and rat post-mitotic differentiated hippocampal
neuronal cells (H19-7 cells) and inhibitory activities of radiolabeled TGF-beta
binding to TGF-beta receptors and TGF-beta-induced plasminogen activator
inhibitor-1 expression, that were approximately 100-670 times more potent than
those of Abeta-(1-40) monomers. At less than micromolar concentrations, Abeta-(1
40)-BSA but not Abeta-(1-40) monomers inhibited proliferation of Mv1Lu cells.
Since TGF-beta is an organizer of responses to neurodegeneration and is also
found in neurite plaques, the TGF-beta antagonist and partial agonist activities
of Abeta monomers and aggregates may play an important role in the pathogenesis
of the disease.
PMID- 9765300
TI - A transcriptional coactivator, steroid receptor coactivator-3, selectively
augments steroid receptor transcriptional activity.
AB - Estrogen receptors ERalpha and ERbeta are members of the family of nuclear
hormone receptors and act as ligand-inducible transcriptional factors, which
regulate the expression of target genes on binding to cognate response elements.
We report here the characterization of steroid receptor coactivator-3 (SRC-3), a
coactivator of nuclear receptor transcription that is a member of a family of
steroid receptor coactivators that includes SRC-1 and transcription intermediate
factor-2. SRC-3 enhanced ERalpha and progesterone receptor-stimulated gene
transcription in a ligand-dependent manner, but stimulation of ERbeta-mediated
transcription was not observed. Protein-protein interaction assays, including
real-time interaction analyses with BIAcore, demonstrated that the affinity of
the ERalpha interaction with SRC-3 was much higher than that observed for the
ERbeta interaction with SRC-3. Mutational analysis suggests a potential interplay
between the transactivation function-1 and -2 domains of ERalpha and SRC-3.
Furthermore, an intrinsic transactivation function was observed in the C-terminal
half of SRC-3. Finally, SRC-3 was differentially expressed in various tissues
and, among several tumor cells examined, was most abundant in the nuclear
fraction of MCF-7 breast cancer cells. Therefore, SRC-3, a third member of a
family of steroid receptor coactivators, has a distinct tissue distribution and
intriguing selectivity between ERalpha and ERbeta.
PMID- 9765301
TI - Differential downstream functions of protein kinase Ceta and -theta in EL4 mouse
thymoma cells.
AB - Sensitive EL4 mouse thymoma cells (s-EL4) respond to phorbol esters with growth
inhibition, adherence to substrate, and production of cytokines including
interleukin 2. Since these cells express several of the phorbol ester-sensitive
protein kinase C (PKC) isozymes, the function of each isozyme remains unclear.
Previous studies demonstrated that s-EL4 cells expressed substantially more
PKCeta and PKCtheta than did EL4 cells resistant to phorbol esters (r-EL4). To
examine potential roles for PKCeta and PKCtheta in EL4 cells, wild type and
constitutively active versions of the isozymes were transiently expressed using a
Sindbis virus system. Expression of constitutively active PKCeta, but not
PKCtheta, in s- and r-EL4 cells altered cell morphology and cytoskeletal
structure in a manner similar to that of phorbol ester treatment, suggesting a
role for PKCeta in cytoskeletal organization. Prolonged treatment of s-EL4 cells
with phorbol esters results in inhibition of cell cycling along with a decreased
expression of most of the PKC isozymes, including PKCtheta. Introduction of
virally expressed PKCtheta, but not PKCeta, overcame the inhibitory effects of
the prolonged phorbol ester treatment on cell cycle progression, suggesting a
possible involvement of PKCtheta in cell cycle regulation. These results support
differential functions for PKCeta and PKCtheta in T cell activation.
PMID- 9765302
TI - Identification of in vivo phosphorylation sites required for protein kinase D
activation.
AB - Protein kinase D (PKD) is activated by phosphorylation in intact cells stimulated
by phorbol esters, cell permeant diacylglycerols, bryostatin, neuropeptides, and
growth factors, but the critical activating residues in PKD have not been
identified. Here, we show that substitution of Ser744 and Ser748 with alanine
(PKD-S744A/S748A) completely blocked PKD activation induced by phorbol-12,13
dibutyrate (PDB) treatment of intact cells as assessed by autophosphorylation and
exogenous syntide-2 peptide substrate phosphorylation assays. Conversely,
replacement of both serine residues with glutamic acid (PKD-S744E/S748E) markedly
increased basal activity (7.5-fold increase compared with wild type PKD). PKD
S744E/S748E mutant was only slightly further stimulated by PDB treatment in vivo,
suggesting that phosphorylation of these two sites induces maximal PKD
activation. Two-dimensional tryptic phosphopeptide analysis obtained from PKD
mutants immunoprecipitated from 32P-labeled transfected COS-7 cells showed that
two major spots present in the PDB-stimulated wild type PKD or the kinase-dead
PKD-D733A phosphopeptide maps completely disappeared in the kinase-deficient
triple mutant PKD-D733A/S744E/S748E. Our results indicate that PKD is activated
by phosphorylation of residues Ser744 and Ser748 and thus provide the first
example of a non-RD kinase that is up-regulated by phosphorylation of
serine/threonine residues within the activation loop.
PMID- 9765303
TI - The mechanism of inhibition of topoisomerase IV by quinolone antibacterials.
AB - Topoisomerase IV (Topo IV) is a mediator of quinolone toxicity in bacteria. In
this work, we demonstrate that norfloxacin, a model quinolone, converts
Escherichia coli Topo IV into a poisonous adduct on DNA as opposed to inhibiting
topoisomerase activity. Norfloxacin inhibition of Topo IV induces a slow decline
in DNA synthesis that parallels cell death. Treatment of cells with a lethal
concentration of the antibacterial did not block chromosome segregation, the
phenotype of catalytic inhibition of Topo IV. Instead, norfloxacin causes DNA
damage, as evidenced by the induction of the SOS pathway for DNA repair; the
increase in susceptibility to the drug by mutations in genes for DNA repair
pathways including recA, recB, and uvrD; and the efficient detergent-induced
linearization of plasmid DNA in drug-treated cells. Wild-type and drug-resistant
alleles of Topo IV are co-dominant, but we find that mutations in recA, seqA, or
gyrB result in unconditional dominance of the sensitive allele, the
characteristic of a poisoning mode of inhibition. These mutations either
compromise chromosome integrity or force Topo IV to play a more active role in
DNA unlinking in front of the replication fork. We interpret our results in terms
of distinct but complementary roles of Topo IV and gyrase in DNA replication.
PMID- 9765304
TI - Transcriptional regulation of mouse mu-opioid receptor gene.
AB - Previously, the existence of dual promoters was reported in mouse mu-opioid
receptor (mor) gene, with mor transcription in the mouse brain predominantly
initiated by the proximal promoter. In this study, we further analyzed the
proximal promoter region, base pairs -450 to -249, to identify cis-DNA regulatory
elements and trans-acting protein factors that are important for mor promoter
activity. The results revealed that a mor inverted GA (iGA) motif and a canonical
Sp1 binding site are required for the promoter activity. Using electrophoretic
mobility shift analysis, we identified nuclear proteins that specifically bind to
the mor iGA motif and that are immunologically related to Sp1 and Sp3. Mutation
of the mor iGA motif, resulting in a loss of Sp binding, led to a 50% decrease in
activity. Mutation of the canonical Sp1 binding site yielded a lesser
(approximately 25%) loss of activity. Mutation of both motifs together resulted
in an approximately 70% decrease in activity. In cotransfection assays using
Drosophila SL2 cells, Sp1 trans-activated the promoter in a manner dependent on
the presence of mor iGA and canonical Sp1 binding motifs. Sp3 can also trans
activate the promoter, and furthermore, Sp1 and Sp3 can trans-activate the mor
promoter additively. Our results suggest that combined or cooperative interaction
of Sp transcription factors within the proximal promoter is necessary for
activation of mor gene transcription.
PMID- 9765305
TI - Transcriptional regulation of cyclooxygenase-2 in mouse skin carcinoma cells.
Regulatory role of CCAAT/enhancer-binding proteins in the differential expression
of cyclooxygenase-2 in normal and neoplastic tissues.
AB - Many studies have suggested that overexpression of cyclooxygenase-2 (COX-2)
contributes to the development of tumors in several tissues. COX-2 expression
tends to be up-regulated in various types of tumors and transformed cell lines,
and the overexpression of COX-2 is caused by enhanced transcription of the gene.
In an attempt to characterize the signaling pathway leading to the overexpression
of COX-2 in the mouse skin carcinoma cell line JWF2, we investigated cis- and
trans-acting factors required for COX-2 expression and demonstrated a molecular
mechanism by which COX-2 is expressed differentially in normal and neoplastic
tissues. Two regions of the COX-2 promoter containing an E-box and nuclear factor
IL6 site were identified as the positive regulatory elements through transient
transfections with luciferase reporter vectors containing the various 5'-flanking
regions of the promoter. Moreover, electrophoretic mobility shift assays and
cotransfection experiments showed that upstream stimulatory factors and
CCAAT/enhancer-binding proteins (C/EBPs) bind to the E-box and nuclear factor IL6
site, respectively, and functionally transactivate the COX-2 promoter. We also
found that C/EBP isoforms are expressed differentially during mouse skin
carcinogenesis, suggesting that overexpression of COX-2 in tumors may be caused
by a change in C/EBP expression levels.
PMID- 9765307
TI - Regulation of adenylyl cyclase by membrane potential.
AB - Mammalian adenylyl cyclases possess 12 transmembrane-spanning domains and bear a
superficial resemblance to certain classes of ion channels. Some evidence
suggests that bacterial and sea urchin sperm adenylyl cyclases can be regulated
by membrane depolarization. In the present study, we explored the effect of
altering membrane potential on the adenylyl cyclase activity of cerebellar
granule cells with acute potassium depolarization. A biphasic stimulatory and
then inhibitory response is evoked by progressive increases in the extracellular
[K]:[Na] ratio in the absence of extracellular Ca2+. This effect does not mimic
the linear increase in membrane potential elicited under the same conditions.
Instead it appears as though membrane depolarization opens L-type (nimodipine
sensitive) Ca2+ channels, allowing the entry of Na+, which directly stimulates
adenylyl cyclase activity. Gramicidin, which generates pores that are permeable
to monovalent cations, and concurrently eliminates the membrane potential,
permits a similar stimulation by extracellularly applied Na+. Although the
results indicate no direct sensitivity of cerebellar granule cell adenylyl
cyclase to membrane potential, they do demonstrate that, as a result of membrane
depolarization, the influx of Na+, as well as Ca2+, will elevate cAMP levels.
PMID- 9765306
TI - Components of the SMRT corepressor complex exhibit distinctive interactions with
the POZ domain oncoproteins PLZF, PLZF-RARalpha, and BCL-6.
AB - Many transcription factors function by repressing gene transcription. For a
variety of these transcription factors the ability to physically recruit
auxiliary proteins, denoted corepressors, is crucial for the ability to silence
gene expression. We and others have previously implicated the SMRT corepressor in
the actions of the PLZF transcription factor and in the function of its oncogenic
derivative, PLZF-retinoic acid receptor (RARalpha), in promyelocytic leukemia. We
report here that PLZF, and a structurally similar transcriptional repressor, BCL
6, can interact with a variety of corepressor proteins in addition to SMRT,
including the mSin3A protein and (for PLZF) histone deacetylase-1. Unexpectedly,
these additional interactions with corepressor components are nonequivalent for
these otherwise similar oncoproteins, suggesting that transcriptional repression
by BCL-6 and by PLZF may differ in mechanism. Furthermore, we demonstrate that
the oncogenic PLZF-RARalpha chimera lacks several important corepressor
interaction sites that are present in the native PLZF protein. Thus the t(11;17)
translocation that creates the PLZF-RARalpha chimera generates an oncoprotein
with potentially novel regulatory properties distinct from those of either
parental protein. Our results demonstrate that otherwise similar transcription
factors can differ notably in their interactions with the corepressor machinery.
PMID- 9765308
TI - A novel transcription initiation factor (TIF), TIF-IE, is required for
homogeneous Acanthamoeba castellanii TIF-IB (SL1) to form a committed complex.
AB - The fundamental transcription initiation factor (TIF) for ribosomal RNA
expression by eukaryotic RNA polymerase I, TIF-IB, has been purified to near
homogeneity from Acanthamoeba castellanii using standard techniques. The purified
factor consists of the TATA-binding protein and four TATA-binding protein
associated factors with relative molecular weights of 145,000, 99,000, 96,000,
and 91,000. This yields a calculated native molecular weight of 460, 000, which
compares well with its mass determined by scanning transmission electron
microscopy (493,000) and its sedimentation rate, which is close to RNA polymerase
I (515,000). Both impure and nearly homogeneous TIF-IB exhibit an apparent
equilibrium dissociation constant of 56 +/- 3 pM. However, although impure TIF-IB
can form a promoter-DNA complex resistant to challenge by other promoter
containing DNAs, near homogeneous TIF-IB cannot do so. An additional
transcription factor, dubbed TIF-IE, restores the ability of near homogeneous TIF
IB to sequester DNA into a committed complex.
PMID- 9765309
TI - Inhibitor-1 interaction domain that mediates the inhibition of protein
phosphatase-1.
AB - Inhibitor-1 (I-1), a cyclic AMP-regulated phosphoprotein, inhibits protein
phosphatase-1 (PP1) activity in response to hormones. The molecular mechanism for
PP1 inhibition by I-1 remains unknown. Mutation of nine acidic residues lining a
proposed I-1-binding channel in rabbit PP1alpha yielded one mutant (E256A)
slightly impaired in its inhibition by I-1, with the IC50 increased by 3-fold,
and one mutant (E275R) located in the beta12-beta13 loop that showed 4-fold
enhanced inhibition by I-1. Substituting Tyr-272, a proposed binding site for the
toxins okadaic acid and microcystin-LR, in the beta12-beta13 loop with Trp, Phe,
Asp, Arg, or Ala impaired PP1alpha inhibition by I-1 by 8-10-fold. Chemical
mutagenesis of the Saccharomyces cerevisiae PP1 gene (GLC7) yielded 20 point
mutations in the PP1 coding region. Two-hybrid analyses and biochemical assays of
these yeast enzymes identified four additional residues in the beta12-beta13 loop
that were required for PP1 binding and inhibition by I-1. Ten-fold higher
concentrations of I-1 were required to inhibit these mutants. Finally, deletion
of the beta12-beta13 loop from PP1alpha maintained full enzyme activity, but
attenuated inhibition by I-1 by >100-fold. These data identified the beta12
beta13 loop in the PP1 catalytic subunit as a domain that mediates binding and
enzyme inhibition by I-1.
PMID- 9765310
TI - The pleckstrin homology domains of dynamin isoforms require oligomerization for
high affinity phosphoinositide binding.
AB - The dynamins are 100-kDa GTPases involved in the scission event required for
formation of endocytotic vesicles. The two main described mammalian dynamins
(dynamin-1 and dynamin-2) both contain a pleckstrin homology (PH) domain, which
has been implicated in dynamin binding to (and activation by) acidic
phospholipids, most notably phosphoinositides. We demonstrate that the PH domains
of both dynamin isoforms require oligomerization for high affinity
phosphoinositide binding. Strong phosphoinositide binding was detected only when
the PH domains were dimerized by fusion to glutathione S-transferase, or via a
single engineered intermolecular disulfide bond. Phosphoinositide binding
specificities agreed reasonably with reported effects of different phospholipids
on dynamin GTPase activity. Although they differ in their ability to inhibit
rapid endocytosis in adrenal chromaffin cells, the dynamin-1 and dynamin-2 PH
domains showed identical phosphoinositide binding specificities. Since
oligomerization is required for binding of the dynamin PH domain to
phosphoinositides, it follows that PH domain-mediated phosphoinositide binding
will favor oligomerization of intact dynamin (which has an inherent tendency to
self-associate). We propose that the dynamin PH domain thus mediates the observed
cooperative binding of dynamin to membranes containing acidic phospholipids and
promotes the self-assembly that is critical for both stimulation of its GTPase
activity and its ability to achieve membrane scission.
PMID- 9765311
TI - Protein kinase C-dependent in vivo phosphorylation of prourokinase leads to the
formation of a receptor competitive antagonist.
AB - We recently reported that in vivo phosphorylation of urokinase-type plasminogen
activator on Ser138/303 prevents its catalytic-independent ability to promote
myelomonocytic cell adherence and motility. We now show that Ca2+ activated,
phospholipid-dependent protein kinase C from rat brain phosphorylates in vitro a
peptide corresponding to prourokinase residues 133-143 (DGKKPSSPPEE) and the full
length molecule on Ser138/139. The in vivo involvement of the protein kinase C
isoenzyme family is supported by the finding that inhibition of kinase C activity
prevents prourokinase phosphorylation on Ser138/303 in A431 human carcinoma
cells. Conversely, a short treatment of A431 cells with phorbol myristate acetate
increases the extent of phosphorylated prourokinase and, concomitantly, affects
its function; under these conditions, the capability of prourokinase to up
regulate U937 monocyte-like cell adherence is severely impaired, although
receptor binding is unaltered. By the aid of a "phosphorylation-like" variant
(Ser138 to Glu) we show that modification of Ser138 is sufficient to confer to
prourokinase the antagonistic properties observed following in vivo stimulation
of protein kinase C activity. These observations provide the first evidence that
protein kinase C directs the formation of a receptor competitive antagonist by
regulating the in vivo phosphorylation state of prourokinase.
PMID- 9765312
TI - MEBA derepresses the proximal myelin basic protein promoter in oligodendrocytes.
AB - The central nervous system expression of myelin basic protein (MBP) is restricted
to oligodendrocytes and is developmentally regulated; these regulatory features
are transcriptionally mediated. We have previously shown that the proximal 149
nucleotides of the MBP promoter were both necessary and sufficient to activate
the transcription of MBP in cultured oligodendrocytes, but not in other cell
types. Sequences within the distal portion of this promoter, which contains a
nuclear factor 1 (NF1) binding site, repressed activation of the MBP promoter in
Cos-7 cells, but not in oligodendrocytes. We now describe a sequence upstream of
and partially overlapping the NF1 site that activates the MBP promoter in
oligodendrocytes, but not in Cos-7 cells. A protein complex binds to this site,
designated MEBA (myelinating glia-enriched DNA binding activity), and is enriched
in nuclear extracts prepared from the brain, oligodendrocytes, and Schwann cells.
The amount of MEBA parallels MBP expression and myelinogenesis in the developing
brain and parallels new MBP expression as purified oligodendrocytes
differentiate. Mutational analyses of binding and function distinguish MEBA, an
activator, from NF1, a repressor of MBP transcription, and suggest that MEBA
consists of at least two proteins. Because the binding sites of MEBA and NF1
overlap, we suggest that MEBA may either compete with or modify NF1 binding,
thereby activating the MBP promoter in oligodendrocytes.
PMID- 9765313
TI - Cloning and expression of a novel, tissue specifically expressed member of the
UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase family.
AB - We report the cloning and expression of the fifth member of the mammalian UDP
GalNAc:polypeptide N-acetylgalactosaminyltransferase (ppGaNTase) family.
Degenerate polymerase chain reaction amplification and hybridization screening of
a rat sublingual gland (RSLG) cDNA library were used to identify a novel isoform
termed ppGaNTase-T5. Conceptual translation of the cDNA reveals a uniquely long
stem region not observed for other members of this enzyme family. Recombinant
proteins expressed transiently in COS7 cells displayed transferase activity in
vitro. Relative activity and substrate preferences of ppGaNTase-T5 were compared
with previously identified isoforms (ppGaNTase-T1, -T3, and -T4); ppGaNTase-T5
and -T4 glycosylated a restricted subset of peptides whereas ppGaNTase-T1 and -T3
glycosylated a broader range of substrates. Northern blot analysis revealed that
ppGaNTase-T5 is expressed in a highly tissue-specific manner; abundant expression
was seen in the RSLG, with lesser amounts of message in the stomach, small
intestine, and colon. Therefore, the pattern of expression of ppGaNTase-T5 is the
most restricted of all isoforms examined thus far. The identification of this
novel isoform underscores the diversity and complexity of the family of genes
controlling O-linked glycosylation.
PMID- 9765314
TI - LY353381.HCl: a novel raloxifene analog with improved SERM potency and efficacy
in vivo.
AB - Body weight, uteri, serum cholesterol and bones were shown previously in vivo to
be sensitive to circulating levels of estrogen, as well as to synthetic,
nonsteroidal ligands termed selective estrogen receptor modulators (SERM). In
this study, we examined the in vivo effects of a new potent SERM on these tissues
in 6-month-old, ovariectomized rats that were orally dosed with 0.0001-10
mg/kg/day LY353381.HCl for 5 weeks. LY353381.HCl prevented the ovariectomy
induced increase in body weight and serum cholesterol levels of treated rats and
lowered them to below sham levels in a dose dependent manner, with maximum
efficacy similar to estrogen or raloxifene. However, LY353381.HCl was
consistently more potent than raloxifene, with a half maximal efficacious dose of
0.001 mg/kg for the reduction of body weight and cholesterol. In the uterus,
LY353381.HCl had marginal effects on uterine weight compared to ovariectomized
controls (OVX) like raloxifene, but unlike estrogen. Histological examination of
uterine epithelial cell height showed little to no stimulatory effect of
LY353381.HCl on the endometrium. Quantitative computed tomographic analyses
(pQCT) of tibiae showed that LY353381.HCl prevented loss of bone due to
ovariectomy with an ED50 of about 0.01 mg/kg with maximal efficacy observed at
0.1-1 mg/kg/day. Maximally attainable bone mineral density and content with
LY353381.HCl were not significantly different from Sham or ovariectomized rats
treated with estrogen or raloxifene. Interestingly, assessment of bone quality by
biomechanical analyses showed that LY353381.HCl preserved the strength of the
femora neck and midshaft, while improving the Young's modulus of cortical bone to
beyond estrogen, raloxifene or sham levels. In uteri of immature rats treated
with estrogen, LY353381.HCl antagonized the estrogen-induced elevation in uterine
weight down to vehicle-dosed control levels with ED50 of 0.03 mg/kg/day.
Therefore, LY353381.HCl was 30-100 times more potent than raloxifene in
preventing ovariectomy effects on body weight, serum cholesterol and bone, while
maintaining estrogen antagonist effects on the uterus. These animal data suggest
that LY353381.HCl may have advantages over estrogen or raloxifene in the
prevention of bone loss and treatment of other tissues in postmenopausal women.
PMID- 9765315
TI - DMPS (2,3-dimercaptopropane-1-sulfonate, dimaval) decreases the body burden of
mercury in humans exposed to mercurous chloride.
AB - DMPS (2,3-dimercaptopropane-1-sulfonate, Na salt), when used as a challenge test
for mercury in workers involved in the production of a calomel skin-bleaching
lotion and in direct contact with mercurous chloride, elevated urine levels of
mercury. A DMPS treatment regimen was devised and initiated. Three days after the
challenge test, DMPS was administered p.o. (400 mg per day) for 8 days, followed
by a no-treatment period of five days. A new cycle of DMPS treatment for 7 days
was initiated and followed by 5 days without treatment. A third period of
treatment was begun for 6 days, followed by a 5-day no-treatment period. The
urinary mercury greatly increased during those periods when DMPS was administered
(1754, 314, and 173 microgram/24 h for the periods 1, 2 and 3, compared with 106,
48 and 53 microgram/24 h on the corresponding no-treatment periods). One of the
workers presented signs of drug intolerance and was discharged after receiving
the first cycle of treatment. DMPS treatment was effective in lowering the body
burden of mercury and in decreasing the urinary mercury concentration to normal
levels.
PMID- 9765317
TI - Metabolic and cardiovascular effects of the adenosine A1 receptor agonist N6-(p
sulfophenyl)adenosine in diabetic Zucker rats: influence of the disease on the
selectivity of action.
AB - Studies were designed to investigate differences in pharmacokinetics and
pharmacodynamics of the adenosine A1 receptor agonist N6-(p-sulfophenyl)adenosine
(SPA) between lean and obese Zucker rats. In conscious rats, time courses of the
effect on heart rate and parameters of lipid metabolism (fatty acids, glycerol)
were monitored in combination with the decline of drug concentrations after i.v.
administration of 100 microgram SPA in 15 min. Small differences in
pharmacokinetics of SPA were observed between lean and obese rats. Values for
clearance and volume of distribution were 1.2 +/- 0.2 ml/min and 88 +/- 10 ml in
lean, and 1.6 +/- 0.1 ml/min and 110 +/- 7 ml in obese animals, respectively.
Modelling of the concentration-heart rate relationship on the basis of the
sigmoidal Emax model revealed no difference in EC50 (99 +/- 12 and 118 +/- 17
ng/ml) or Emax (-191 +/- 16 and -185 +/- 22 bpm) between the lean and obese rats.
The metabolic effects of SPA were totally different between lean and obese rats.
Potent (EC50 = 18 +/- 3 ng/ml) inhibition of lipolysis was observed in the lean
rats. In obese rats, SPA was less potent (EC50 = 109 +/- 36 ng/ml) resulting in
short lasting antilipolytic effect. Furthermore, administration of SPA resulted
in a significant decrease in insulin concentrations. These findings show that
changes in glucose and lipid metabolism may be associated with an altered
sensitivity to the antilipolytic actions of adenosine A1 receptor agonists.
PMID- 9765316
TI - Exposure to ochratoxin A impairs organic anion transport in proximal-tubule
derived opossum kidney cells.
AB - Ochratoxin A (OTA) is a widespread mycotoxin, which is nephrotoxic and
carcinogenic. Because a decline in net-secretion of para-aminohippuric acid (PAH)
was observed after chronic OTA exposition in vivo, we investigated the effect of
OTA on proximal-tubule-derived opossum kidney (OK) cells. OTA up to 10(-5)
mol/liter had no acute effect on PAH transport when bovine serum albumin (BSA)
was present. By contrast, 72-hr incubation of OK cells led to a decrease of PAH
transport with half-maximal inhibition at 6 . 10(-7) mol/liter for
transepithelial secretion and 6 . 10(-8) mol/liter for basolateral uptake of PAH.
Incubation of OK cells with 10(-6) mol/liter OTA for 72 hr reduced the affinity
of PAH uptake, and decreased the maximum secretion rate to one-fifth of control
values. Apical uptake of amino acids and basolateral uptake of glutarate were not
affected. In addition, no signs of general toxic action could be observed.
Specific basolateral binding affinity of PAH was reduced to 50% of control.
Furthermore, incubation with OTA led to a decrease of PAH efflux across the
apical membrane, although efflux across the basolateral membrane and the amount
remaining in the cells increased as compared to control. By contrast to control
cells, uptake of PAH in OTA-treated cells was not stimulated after preloading
with glutarate. Our data show, that 1) long-term incubation with free OTA in the
nanomolar range reduces the activity of the organic anion transporter, 2) without
influencing general cell function. 3) OTA seems to act preferentially on organic
anion transport, by affecting the exchange of organic anions and dicarboxylates.
4) Thereby, OTA reduces its own secretion. 5) The excretion of other xenobiotics
and drugs may be also impaired, whereby OTA can exert an indirect toxic action.
PMID- 9765318
TI - Excretion of ofloxacin into saliva in rats with renal failure.
AB - To clarify effects of renal failure on salivary distribution of ofloxacin (OFLX),
a quinolone antibiotics, blood, parotid and mandibular saliva were collected from
the single-step 5/6th-nephrectomized and sham-operated (control) rats after bolus
i. v. administration of OFLX (5 mg/kg). The concentrations of OFLX in these
samples were determined by high-performance liquid chromatography. Renal failure
induced by the partial nephrectomy significantly elevated plasma levels and
cumulative salivary excretion of OFLX when compared to control rats. Total body
clearance was significantly decreased by the renal failure, although salivary
clearance of the partially nephrectomized rats was about three times larger than
that of the control. At the terminal phase, the saliva/plasma concentration
ratios of OFLX for parotid and mandibular saliva in control rats was 0.249 +/-
0.180 and 0.136 +/- 0.024, respectively, and there was a significant difference
between both salivary glands. The saliva/plasma concentration ratios in the rats
with renal failure were significantly greater than those in the control group in
both parotid (about 3.2 times) and mandibular (about 2.5 times) saliva. The
results of this study suggest that the salivary excretion of OFLX is
significantly increased by renal failure and a glandular difference in the
salivary excretion of OFLX exists in both rats with normal and impaired renal
function.
PMID- 9765319
TI - Transport of temocaprilat into rat hepatocytes: role of organic anion
transporting polypeptide.
AB - The mechanism for hepatic uptake of temocaprilat, an angiotensin-converting
enzyme inhibitor that is predominantly excreted into bile was studied using
isolated rat hepatocytes and COS-7 cells expressing the organic anion
transporting polypeptide (oatp1). The uptake of temocaprilat into isolated rat
hepatocytes exhibited saturation with a Km of 20.9 microM and a Vmax of 0.21
nmol/min/mg protein. This uptake was temperature sensitive and was significantly
reduced by metabolic inhibitors, a sulfhydryl-modifying reagent and an anion
exchange inhibitor, although the replacement of Na+ with Li+ in the medium did
not affect the uptake. [3H]Temocaprilat uptake was inhibited by estradiol-17beta
D-glucuronide and dibromosulphophthalein, typical substrates for the Na+
independent organic anion transporter, in a concentration-dependent manner,
whereas excess estradiol-17beta-D-glucuronide did not completely inhibit the
uptake. Temocaprilat uptake into COS-7 cells transfected with oatp1 cDNA revealed
a concentration-dependency with a Km of 46.7 microM, a value comparable with that
obtained in isolated hepatocytes. The contribution of oatp1 to carrier-mediated
hepatic uptake of temocaprilat was less than 50% by correcting the uptake
clearance with that of estradiol-17beta-D-glucuronide. A good linear correlation
was observed for the inhibitory effect of angiotensin-converting enzyme
inhibitors (benazeprilat, cilazaprilat, delaprilat and enalaprilat) between
isolated hepatocytes and oatp1-expressing cells. These data suggest that oatp1,
along with another transporter(s), mediates the uptake of angiotensin-converting
enzyme inhibitors into rat hepatocytes.
PMID- 9765320
TI - Sch 50971, an orally active histamine H3 receptor agonist, inhibits central
neurogenic vascular inflammation and produces sedation in the guinea pig.
AB - We studied the actions of Sch 50971, a novel histamine H3 receptor agonist, in an
experimental neurogenic model of migraine and characterized its sedative and
respiratory actions. Sch 50971 (i.v. and p.o) inhibited plasma protein
extravasation in the dura mater of guinea pigs after electrical stimulation of
the trigeminal ganglia. The minimum effective doses of Sch 50971 were 3.0 mg/kg
i.v. and 10 mg/kg p.o., which produced a 40% and 42% decrease in plasma protein
extravasation, respectively. The effects of Sch 50971 (3.0 mg/kg i.v. ) were
blocked by the histamine H3 antagonist thioperamide (3.0 mg/kg i.v.). The 5-HT1D
agonist, sumatriptan (0.3 mg/kg i.v.), and the histamine H3 agonist, (R)-alpha
methylhistamine (0.3 mg/kg), also inhibited plasma extravasation by 40 and 46%.
In sedation studies, Sch 50971 (1-100 mg/kg p.o.) potentiated pentobarbital
induced sleep. The ED40 min for Sch 50971, the benzodiazepines triazolam and
diazepam, the histamine H1 antagonist diphenhydramine and the H3 receptor agonist
(R)-alpha-methylhistamine were 7.0, 0.5, 2.3, 14.1 and 23.4 mg/kg p. o.,
respectively. The sedative effects of oral Sch 50971 was blocked by thioperamide
(10 microgram i.c.v.). The sedative activity of Sch 50971 was also examined using
EEG activity, locomotor activity and sleep. In conscious guinea pigs, Sch 50971
(10 mg/kg p.o.) depressed locomotor activity, increased total sleep time and
produced EEG patterns consistent with physiological sleep. Sch 50971 decreased
beta wave activity but had no effects on delta wave activity, theta activity or
alpha wave activity. In contrast, triazolam (1.0 mg/kg p. o.) depressed delta and
theta wave activity and produced large increases in alpha and beta wave activity.
In conclusion, Sch 50971 is an orally active, potent and selective agonist of
histamine H3 receptors that may act to ameliorate the sequelae of migraine
headaches, where activation of histamine H3 receptors may be beneficial. Sch
50971 also decreases motor activity and promotes EEG activity consistent with
physiological sleep.
PMID- 9765321
TI - Effects of acute and repeated administration of amisulpride, a dopamine D2/D3
receptor antagonist, on the electrical activity of midbrain dopaminergic neurons.
AB - Electrophysiological techniques were used to study the effects of amisulpride, a
D2/D3 dopamine receptor blocker, on the activity of dopaminergic neurons in the
substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA).
Administration of single bolus doses of amisulpride (8-32 mg/kg i.v.) induced a
dose-dependent increase in the basal activity of dopaminergic neurons, in both
the SNc and the VTA. The effect of amisulpride was more evident in the VTA, where
it elicited a maximal excitation of 38.5 +/- 12%, whereas in the SNc it caused a
peak excitation of only 22.1 +/- 9.8%. Amisulpride also increased the bursting
activity of dopaminergic neurons in the VTA but not in the SNc.
Microiontophoretic application of amisulpride (10-40 nA) into the SNc and the VTA
caused an increase in the basal firing rate of the majority of dopaminergic
neurons sampled. The excitation induced by 40 nA amisulpride was more marked in
the VTA (36.1 +/- 21%) than in the SNc (25.0 +/- 18%). Moreover,
microiontophoretic amisulpride (40 nA) increased the bursting activity of
dopaminergic neurons in the VTA only. Repeated administration of amisulpride (20
and 50 mg/kg i.p.) for 21 consecutive days produced a significant decrease in the
number of spontaneously active dopaminergic neurons in the VTA but not in the
SNc. Repeated admistration of haloperidol (0.5 mg/kg i.p. ) decreased the number
of dopaminergic cells both in the SNc and the VTA. The effect of repeated
admistration of amisulpride on the activity of VTA dopaminergic neurons was
reversed by apomorphine, suggesting that these neurons were probably under a
state of depolarization block. Taken together, these data confirm previous
findings indicating that low doses of amisulpride preferentially increase
dopaminergic transmission in the mesolimbic system. Moreover, results obtained
from long-term experiments are consistent with clinical data indicating that
amisulpride given at high doses is an effective antipsychotic agent, associated
with a low incidence of extrapyramidal side effects.
PMID- 9765322
TI - Imidazenil, a positive allosteric GABAA receptor modulator, inhibits the effects
of cocaine on locomotor activity and extracellular dopamine in the nucleus
accumbens shell without tolerance liability.
AB - Imidazenil, a benzodiazepine recognition site ligand that acts as partial
positive allosteric modulator of gamma-aminobutyric acid (GABA) action at GABAA
receptors, inhibits in a dose-dependent manner (0.56-2.5 micromol/kg i.p. to
rats) the cocaine-induced increase in dopamine (DA) content in the dialysates of
the nucleus accumbens shell and striatum and also inhibits cocaine-induced
locomotor activity. Diazepam, a full allosteric modulator of GABA action at GABAA
receptors, in a dose of 4.4 micromol/kg i.p. also attenuates the cocaine-induced
increase in DA content in the dialysates of nucleus accumbens shell, and striatum
and the cocaine-induced locomotor activity. However, imidazenil (2.5 micromol/kg
i.p.) fails to reduce spontaneous locomotor activity, whereas diazepam (4.4
micromol/kg i.p.) elicits sedation and ataxia and clearly impairs spontaneous
locomotor activity. When added in vitro, both imidazenil and diazepam potentiate
the GABA-mediated reduction of the ventral tegmental area DA neuron firing rate.
After protracted treatment (14 days/three times a day with an increasing-dose
schedule), the inhibitory actions of imidazenil fail to develop tolerance,
whereas the actions of diazepam exhibit high tolerance liability. We conclude
that imidazenil is devoid of tolerance liability and that, via a GABAA-mediated
reduction in the extracellular DA in nucleus accumbens shell, it might reduce the
psychomotor activity and reinforcing properties of cocaine.
PMID- 9765323
TI - Pharmacokinetics and biological actions of subcutaneously administered human
brain natriuretic peptide.
AB - Human brain natriuretic peptide (hBNP) has demonstrated favorable hemodynamic
effects in patients with congestive heart failure; however, the peptidic nature
of this compound has focused clinical testing on protocols involving intravenous
delivery. We have studied subcutaneous delivery as an alternative method of
administering hBNP. Administration of 30 microgram/kg hBNP by either subcutaneous
or intravenous delivery protocols resulted in significant hBNP-immunoreactive
material in the plasma with area under the plasma concentration-time curve values
of 310 +/- 20 nmolxmins/liter and 187 +/- 47 nmolxmins/liter, respectively.
Plasma cyclic GMP, a surrogate marker of activation of the biological receptor
for hBNP, was elevated for a longer period of time following subcutaneous
delivery compared with intravenous delivery. Subcutaneous delivery of 30
microg/kg hBNP resulted in natriuresis, diuresis and reduced systolic blood
pressure in anesthetized normotensive rabbits, effects similar in magnitude yet
prolonged in duration compared with those elicited by the same dose of hBNP
delivered intravenously. Systolic blood pressure following hBNP treatment
remained below base-line values for 50 and 150 min following intravenous and
subcutaneous delivery protocols, respectively. These results suggests that
subcutaneous delivery of hBNP may be a viable therapeutic alternative to
intravenous modes of delivery.
PMID- 9765324
TI - Corticosterone facilitates the acquisition of cocaine self-administration in
rats: opposite effects of the type II glucocorticoid receptor agonist
dexamethasone.
AB - The effect of corticosterone on the acquisition of cocaine-seeking behavior was
investigated in rats using ascending dose-response curves for intravenous cocaine
self-administration. Rats pretreated daily with corticosterone (2.0 mg/kg i.p.)
acquired cocaine self-administration at a lower dose compared with vehicle
treated controls. In contrast, daily corticosterone pretreatment did not alter
food-maintained responding. Cocaine self-administration was not affected by the
type I (mineralocorticoid) receptor agonist, aldosterone (100 microgram/kg).
However, rats treated with the type II (glucocorticoid) receptor agonist,
dexamethasone (10 or 100 microgram/kg) did not acquire self-administration at any
dose tested. The 100 microgram/kg dose of dexamethasone attenuated food
reinforced behavior and decreased body weight, but these effects were not
observed with the 10 microgram/kg dose. Dexamethasone dose-dependently attenuated
the plasma corticosterone response to self-administered infusions or
intraperitoneal injections of cocaine, indicating that the ability of
dexamethasone to block cocaine-induced corticosterone secretion may have
contributed to its effects on self-administration. Administration of aldosterone
(100 microgram/kg) together with 10 microgram/kg dexamethasone restored self
administration to the level of vehicle-treated rats, suggesting that type I
receptor occupation by corticosterone may be required for the acquisition of this
behavior. These results indicate that stress-induced corticosterone secretion may
provide a substrate through which stressors interact with cocaine reinforcement.
Additionally, the finding that dexamethasone blocks the acquisition of cocaine
self-administration may be relevant to the development of novel approaches to the
treatment of cocaine addiction.
PMID- 9765325
TI - Antagonism by class I antiarrhythmic drugs of levcromakalim-induced relaxation in
isolated rat aorta.
AB - We have analyzed the effects of several class I antiarrhythmic drugs
(propafenone, quinidine, its enantiomer quinine, disopyramide, flecainide and
mexiletine), tetraethylammonium (TEA) and glibenclamide on the vasodilator
effects of the adenosine 5'-triphosphate-dependent K+ channels channel opener
levcromakalim in isolated rat aorta precontracted by 30 mM KCl. TEA (>1 mM) and
disopyramide (>/=10 microM), induced a sustained contraction in resting aortic
rings. Propafenone (>/=3 microM), quinidine (>/=30 microM), disopyramide (>/=100
microM) and flecainide (>/=100 microM) but not the other drugs decreased the
contraction induced by 30 mM KCl in a concentration-dependent manner. Propafenone
(>/=1 microM), quinidine (>/=10 microM), quinine (>/=1 microM), disopyramide
(>/=3 microM), flecainide (>/=100 microM), mexiletine (>/=3 microM), TEA (>/=0.3
mM) and glibenclamide (>/=0.1 microM) caused a concentration-dependent inhibition
of the vasodilation induced by levcromakalim in rat aortic rings. The order of
potency of the drugs, expressed as pD2 values, to inhibit the vasodilation
induced by 0.3 microM levcromakalim was the following: glibenclamide (6.84) >
quinine (6.14) > propafenone (5.27) > disopyramide (5.03) > quinidine (4.80) >
mexiletine (4.68) > flecainide (3.37) > TEA (3. 20). With the exception of
flecainide and mexiletine, the slopes of the Schild plots were similar to unity.
Based on the mode of antagonism these drugs could be classified in four groups:
1) glibenclamide which only shifted the curves to the right, 2) quinidine and
disopyramide that, at low concentrations, shifted the curve to the right but, at
higher concentrations, it also reduced the maximal relaxant effect, 3)
propafenone, quinine and TEA that shifted the curve rightwards and reduced the
maximal relaxation at all concentrations and 4) flecainide and mexiletine whose
Schild slopes were clearly different from unity. In conclusion, class I
antiarrhythmic drugs inhibited levcromakalim-induced relaxation in isolated rat
aorta. The concentrations at which these effects were observed were within the
therapeutic range (except for flecainide) and similar to those reported to
inhibit adenosine 5'-triphosphate-dependent K+ channel currents. Analysis of the
concentration-response curves revealed that these drugs produced a noncompetitive
antagonism of levcromakalim-induced relaxations.
PMID- 9765326
TI - Evidence for a causative role of N-methyl-D-aspartate receptors in an in vitro
model of alcohol withdrawal hyperexcitability.
AB - Synaptic mechanisms underlying hyperexcitability due to withdrawal from chronic
ethanol exposure were investigated in a hippocampal explant model system using
electrophysiological techniques. Whole-cell voltage clamp recordings from CA1
pyramidal cells demonstrated that acute ethanol exposure inhibited N-methyl-D
aspartate receptor (NMDAR)-mediated excitatory postsynaptic currents by over 40%.
Chronic ethanol exposure for 6 to 11 days at 35 or 75 mM induced no differences
from control explants in the fast component of the population synaptic response
(non-NMDAR-mediated). Prolonged field potential recordings (to 10 hr) were used
to monitor the withdrawal process in vitro. Ethanol-exposed explants from both 35
and 75 mM groups displayed an increase (60% and 89%, respectively) in the NMDAR
mediated component of synaptic transmission on withdrawal from chronic exposure.
Prolonged tonic-clonic electrographic seizure activity was consistently observed
after ethanol withdrawal only after the increase in NMDAR function. This
hyperexcitability was inhibited by the NMDAR antagonist D-2-amino-5
phosphonovaleric acid and returned once the NMDAR component was reestablished
after antagonist washout. In situ hybridization studies suggest that expression
of NR2B subunit mRNA may be enhanced in explants after chronic ethanol exposure.
No lasting differences were observed in the NMDAR component after acute in vitro
ethanol exposure and withdrawal. These data suggest that the occurance of ethanol
withdrawal hyperexcitability in this system may be directly dependent on
alterations in NMDAR function after chronic exposure. Since this region and
others that contain ethanol sensitive NMDARs may serve as epileptic foci, long
term alterations in NMDAR function may be expected to generate paroxysmal
depolarizing shifts underlying ictal events after withdrawal from ethanol
exposure.
PMID- 9765327
TI - Calcium source diversity in canine lower esophageal sphincter muscle.
AB - Tonic contraction of the lower esophageal sphincter (LES) prevents
gastroesophageal reflux. LES tone is produced both by cholinergic nerve and
myogenic activities. The Ca++ sources for LES tone and carbachol-induced
contraction in canine LES strips were determined from the effect on contractile
activity of extracellular Ca++ level modulation, Ca++ entrance blockade or
enhancement with nifedipine or BayK8644 respectively, and/or inhibition of Ca++
store refilling using the sarcoplasmic reticulum Ca++ pump inhibitor,
cyclopiazonic acid. LES tone disappeared when a Ca++-free physiological saline
solution or nifedipine was applied. Sustained Ca++ free contractions to carbachol
were prevented/abolished by nifedipine or increased Ca++ chelation and enhanced
by BayK8644. Inhibition of sarcoplasmic reticulum Ca++ pumps by cyclopiazonic
acid reduced Ca++ free contractions to carbachol; BayK8644 restored cyclopiazonic
acid-reduced Ca++ free contractions to carbachol. Therefore, some Ca++ stores can
be refilled by mechanisms not requiring activity of the sarcoplasmic reticulum
Ca++ pump. A preferred pathway may exist whereby Ca++ enters stores directly
through L-Ca++ channels. The proposed Ca++ store refilling mechanism involves
continuous Ca++ entry through L-Ca++ channels from sites not equilibrated with
external Ca++. Therefore, diverse Ca++ stores exist in canine LES which are
dependent on Ca++ influx through L-Ca++ channels.
PMID- 9765328
TI - The effects of methamphetamine on the production of free radicals and oxidative
stress.
AB - The effects of methamphetamine (METH) on pro-oxidant processes and on the
production of reactive oxygen species were examined in vivo in the rat brain. The
presence of oxidative damage in striatum, as revealed by the oxidation of lipid,
also was assessed via the measurement of the lipid peroxidation product
malonyldialdehyde. To elucidate further the mechanisms mediating METH-induced
oxidative stress, we studied the possible reversal of the long-term METH-induced
decrease in striatal dopamine content by antioxidants through iron chelation and
trapping of free radicals. The uric acid concentration in the striata of rats
killed 1 hr, but not 24 hr, after a four-injection regimen of METH was increased
significantly compared with saline-injected control rats. METH increased the in
vivo formation of the hydroxylated products of salicylate and d-phenylalanine, as
evidenced by the elevated extracellular concentrations of 2,3 dihydroxybenzoic
acid and p-tyrosine, respectively. The local perfusion of the striatum with the
iron chelator deferroxamine attenuated the long-term depletions of striatal
dopamine content produced by METH. In other experiments, malonyldialdehyde
concentrations in incubated striatal homogenates were elevated significantly in
METH-treated rats. Finally, pretreatment with the spin trapping agent
phenylbutylnitrone before the METH injections attenuated the subsequent long-term
depletions in striatal dopamine content. Overall, the results illustrate that
METH increases pro-oxidant processes and offer supportive evidence that METH
produces oxidative damage. These studies also demonstrate that iron may be
involved in mediating the long-term damage to dopamine neurons after repeated
administrations of METH.
PMID- 9765329
TI - Stimulation of cholesterol release from rabbit foam cells by the action of a new
inhibitor for acyl CoA:cholesterol acyltransferase (ACAT), HL-004.
AB - A new inhibitor of acyl CoA:cholesterol acyltransferase (ACAT), HL-004 [N-(2, 6
diisopropylphenyl)tetradecylthioacetamide], suppressed the synthesis of
cholesterol [14C]oleate at 10(-9) approximately 10(-7) M in a concentration
dependent manner in both THP-1 cell-derived macrophages and foam cells prepared
from aortic intima of rabbits fed a high cholesterol diet. Incorporation of
[3H]cholesterol oleate-beta very low density lipoproteins was not inhibited by HL
004 at 10(-9) approximately 10(-7) M. Release of radioactivity from the cells
loaded with [3H]cholesterol oleate-beta very low density lipoproteins was
increased by the inhibition of ACAT activity with HL-004. HL-004 did not affect
on acid and neutral cholesterol esterases. As a result, cholesterol ester content
in foam cells decreased. These data suggested that HL-004 decreases cholesterol
ester in foam cells by increasing the release of cholesterol and therefore might
suppress atherosclerotic lesions.
PMID- 9765330
TI - The selective norepinephrine reuptake inhibitor, LY368975, reduces food
consumption in animal models of feeding.
AB - The compound, LY368975 ((R)-thionisoxetine) is a potent and selective inhibitor
of the norepinephrine (NE) reuptake site. We evaluated the in vivo properties of
LY368975 in various animal models. In mice, LY368975 prevented heart NE depletion
by 6-hydroxydopamine with an ED50 of 1.22 mg/kg. In rats, orally administered
LY368975 inhibited 3H-NE uptake into hypothalamic synaptosomes ex vivo with an
ED50 of 2.5 mg/kg and 3H-tomoxetine binding to the NE transporter with an ED50 of
2.7 mg/kg. When rats were deprived of food for 18 hr, 10 mg/kg LY368975 was able
to suppress food intake 1, 2 and 4 hr after reintroduction of the feed. In
nonfasted rats trained to drink sweetened condensed milk, LY368975 produced a
dose-dependent reduction in consumption with a 44% decrease at 3 mg/kg. At doses
up to 10 mg/kg p.o., LY368975 produced no significant effects on locomotor
activity suggesting the compound does not activate or sedate the animals at
pharmacologically relevant doses. Therefore, LY368975 is an orally available and
centrally active NE reuptake inhibitor that is capable of reducing food
consumption in rodents. Compounds of this class may have use in the treatment of
obesity and eating disorders.
PMID- 9765331
TI - Epithelial ion transport and barrier abnormalities evoked by superantigen
activated immune cells are inhibited by interleukin-10 but not interleukin-4.
AB - Many studies have indicated an association between bacteria and the severity of
enteric secretory or inflammatory disorders. We previously showed that monolayers
of human T84 epithelial cells display altered ion transport and permeability
after coculture with Staphylococcus aureus enterotoxin B (SEB, a model
superantigen)-activated immune cells, where interferon-gamma and tumor necrosis
factor-alpha were key mediators in the pathophysiology. Here we examined whether
the regulatory Th2-type cytokines, interleukin (IL)-10 and IL-4, could prevent
these epithelial irregularities. T84 monolayers were cocultured with human
peripheral blood mononuclear cells (PBMC) or T cell-enriched, monocyte-depleted
PBMC (T + B cells) +/- SEB for 20 hr in the presence or absence of IL-10 or IL-4.
Subsequently, T84 monolayers were mounted in Ussing chambers and ion transport
(short-circuit current (Isc) and DeltaIsc evoked by forskolin) and permeability
(ion resistance and probe fluxes) were assessed. IL-10 dose-dependently inhibited
the increased T84 permeability and the reduced responsiveness to forskolin that
were evoked by coculture with SEB-activated PBMC or T + B cells. Similar changes
in T84 function occurred in response to conditioned medium from SEB-activated
immune cells; however, addition of IL-10 to the conditioned medium did not
prevent the changes in epithelial function. In contrast, when PBMC were
stimulated with SEB in the presence of IL-10, the subsequent conditioned medium
was less effective in evoking altered epithelial function. These data suggest
that the affect of IL-10 was due to effects on the immune cells and not directly
on the epithelium. In contrast to IL-10, IL-4 did not ameliorate any of the
immune-mediated changes in T84 function. We conclude that IL-10 can reduce the
epithelial functional changes caused by SEB-activated immune cells and this data
adds further support for IL-10 immunotherapy in the treatment of intestinal
secretory or inflammatory disorders.
PMID- 9765332
TI - Inflammation modifies the role of cyclooxygenases in the contractile responses of
the rat detrusor smooth muscle to kinin agonists.
AB - The contractile responses elicited by the selective kinin B1 and B2 receptor
agonists [desArg9]-bradykinin ([desArg9]-BK) and [Hyp3, Tyr(Me)8]-bradykinin
([Hyp3, Tyr(Me)8]-BK) (1 nM-10 microM), respectively, were evaluated in control
vs. inflamed (cyclophosphamide 150 mg kg-1 i.p., 48 h before the sacrifice) rat
isolated urinary bladder strips. The contractile responses to the B2 receptor
agonist did not differ in control vs. inflamed bladders, whereas the contractile
responses to [desArg9]-BK were potentiated in inflamed bladders. The selective B1
and B2 receptor antagonists B 9858 (H-Lys-Lys-Arg-Pro-Hyp-Gly-Igl-Ser-DIgl-Oic
OH) and Hoe 140 (H-DArg-Arg-Pro-Hyp-Gly-Thi-Ser-DTic-Oic-Arg-OH), both at 1
microM, inhibited the response to the B1 and B2 receptor agonists, respectively,
in both control and inflamed bladders. In addition, the concentration-response
curve to [Hyp3, Tyr(Me)8]-BK was shifted to the right and depressed by B 9858 in
inflamed bladders. The nonselective cyclooxygenase (COX) inhibitors S-(-)
ketoprofen (10 microM) and piroxicam (30 microM) markedly depressed the
concentration-response curves to [desArg9]-BK and [Hyp3, Tyr(Me)8]-BK in control
bladders, but neither drug affected the B1 or B2 receptor agonist-mediated
responses in inflamed bladders. The selective inhibitor of the inducible COX-2
isoenzyme, NS-398 (1 microM), did not inhibit the contractile responses to
[desArg9]-BK and [Hyp3, Tyr(Me)8]-BK in either control or inflamed bladders,
whereas it significantly potentiated the response to the B1 receptor agonist in
inflamed bladders. The exogenous administration of prostaglandin E2 (PGE2)
induced S-(-)-ketoprofen-resistant contractile responses that were depressed in
inflamed bladders. Pretreatment with S-(-)-ketoprofen restored the PGE2-mediated
contractile responses of inflamed bladders to control values. PGE2 assay revealed
that the basal production of PGE2 is significantly higher after inflammation than
in control conditions. [desArg9]-BK and [Hyp3, Tyr(Me)8]-BK (1 microM each) both
stimulated PGE2 production, and their effect was larger in inflamed than in
control bladders. Piroxicam (30 microM) prevented the PGE2 production evoked by
[desArg9]-BK in both control and inflamed bladders and likewise abolished that
produced by [Hyp3, Tyr(Me)8]-BK. NS-398 (1 microM) reduced the PGE2 production
elicited by [desArg9]-BK in control and inflamed bladders. When NS-398 was tested
on the [Hyp3, Tyr(Me)8]-BK-induced PGE2 production, it inhibited PGE2 production
in the inflamed bladders only, without significantly modifying the response
obtained in controls. These findings demonstrate that 1) in normal bladders, the
activation of B1 and B2 receptors evokes contraction that is largely mediated by
COX-1 metabolites, whereas the COX-2 appears to be involved in PGE2 production
after the activation of B1 receptor only, without interfering with contraction,
and 2) in inflamed bladders, the activation of B1 and B2 receptors still produce
PGE2, but the contractile response is not reduced by COX inhibitors, a result
that indicates that additional mechanisms play a compensatory role.
PMID- 9765333
TI - Central GABAA and GABAB receptor modulation of basal and stress-induced plasma
interleukin-6 levels in mice.
AB - To investigate the modulatory roles of central gamma-aminobutyric acid (GABA)A
and GABAB receptors in the regulation of basal and stress-induced plasma
interleukin-6 (IL-6) levels, we examined the effects of i.c.v. injection of GABA
receptor agonists and antagonists on basal and restraint stress-induced plasma IL
6 levels in mice. Muscimol (20-200 ng), a GABAA receptor agonist, and baclofen (5
20 ng), a GABAB receptor agonist, injected i.c.v. did not affect the basal levels
of plasma IL-6. In the restraint-stressed animals, muscimol and baclofen
inhibited the stress-induced plasma IL-6 levels from the dose of 50 and 15 ng,
respectively. 2-(3-Carboxyl)-3-amino-6-(4-methoxyphenyl)-pyridazinium bromide (SR
95,531; 0.3-10 ng), a GABAA receptor antagonist, and 2-hydroxysaclofen (1-10
microgram), a GABAB receptor antagonist, injected i.c.v. increased both the basal
and the restraint stress-induced plasma IL-6 levels. The i.p. pretreatment of
animals with 6-hydroxydopamine (100 mg/kg) for 3 days significantly inhibited SR
95,531 (3 ng i.c.v.)- but not 2-hydroxysaclofen (10 microg i.c.v.)-induced
increase in the basal plasma IL-6 levels. These data suggest that central GABAA
and GABAB receptors are involved in the suppressive modulation of basal and
restraint stress-induced plasma IL-6 levels in mice.
PMID- 9765334
TI - Exogenous leukotriene B4 (LTB4) inhibits human neutrophil generation of LTB4 from
endogenous arachidonic acid during opsonized zymosan phagocytosis.
AB - The effect of exogenous leukotriene B4 (LTB4) on opsonized zymosan-stimulated
human neutrophil formation of 5-lipoxygenase products and arachidonic acid
release was directly assessed using reverse-phase HPLC/tandem mass spectrometric
methods for quantitation. Stable isotopically labeled LTB4, [1,2-13C2]LTB4,
caused a dose-dependent inhibition of LTB4 production in isolated human
neutrophils with significant inhibition (60 +/- 7% of control levels) when 0.12
nM [13C2]LTB4 was present. Production of 5-hydroxy-6,8,11,14-eicosatetraenoic
acid and release of free arachidonic acid were also dose-dependently inhibited by
exogenous LTB4. Metabolites of LTB4, 20-hydroxy-LTB4 and 3(S)-hydroxy-LTB4, also
significantly reduced LTB4 production to levels as low as 10 +/- 6% and 10 +/- 7%
of control levels, respectively, when present exogenously at 10 nM. Exogenous 5
hydroxy-6,8,11,14-eicosatetraenoic acid at concentrations as high as 10 nM
produced no significant reduction in LTB4 biosynthesis during zymosan-stimulated
human neutrophil production of LTB4. The inhibitory effect of LTB4 could be
partially reversed by the LTB4 receptor antagonist U 75302. Furthermore, an
alternative stimulus, N-formyl-methionyl-leucyl-phenylalanine (100 nM), did not
inhibit the production of LTB4 in opsonized zymosan-stimulated human neutrophils.
These results suggest that activation of the LTB4 receptor on the human
neutrophil during phagocytosis limits the ultimate biosynthesis of LTB4. This
autocrine effect is opposite to that observed when neutrophils have much of the
signal transduction pathways bypassed when stimulated with calcium ionophore
A23187 or treated with exogenous free arachidonic acid.
PMID- 9765335
TI - Novel, selective delta6 or delta5 fatty acid desaturase inhibitors as
antiinflammatory agents in mice.
AB - Decreased synthesis of arachidonic acid by inhibition of the Delta6 or Delta5
desaturase was evaluated as a means to mitigate inflammation. Using quantitative
in vitro and in vivo radioassays, novel compounds representing five classes of
Delta5 desaturase inhibitors and one class of Delta6 desaturase inhibitor were
identified. The Delta6 desaturase inhibitor, SC-26196, had pharmacokinetic and
pharmacodynamic profiles in mice that allowed for the evaluation of the
pharmacological effects of chronic inhibition of desaturase activity. SC-26196
decreased edema to the same extent as indomethacin or essential fatty acid
deficiency in the carrageenan paw edema model in the mouse. The antiinflammatory
properties of SC-26196 were consistent with its mechanism of action as a Delta6
desaturase inhibitor: 1) A correlation existed between inhibition of liver Delta6
desaturase activity and decreases in edema. 2) The onset of the decrease in edema
was time dependent. 3) Selective reduction of arachidonic acid occurred dose
dependently in liver, plasma and peritoneal cells. 4) In the presence of SC
26196, controlled refeeding of arachidonic acid, but not oleic acid, reversed the
changes resulting from desaturase inhibition. The Delta6 desaturase may be a
target for development of antiinflammatory drugs whose mechanism of action is
unique.
PMID- 9765336
TI - S 18126 ([2-[4-(2,3-dihydrobenzo[1,4]dioxin-6-yl)piperazin-1-yl methyl]indan-2
yl]), a potent, selective and competitive antagonist at dopamine D4 receptors: an
in vitro and in vivo comparison with L 745,870 (3-(4-[4-chlorophenyl]piperazin-1
yl)methyl-1H-pyrrolo[2, 3b]pyridine) and raclopride.
AB - The novel benzoindane S 18126 possessed > 100-fold higher affinity at cloned,
human (h) D4 (Ki = 2.4 nM) vs. hD2 (738 nM), hD3 (2840 nM), hD1 (> 3000 nM) and
hD5 (> 3000 nM) receptors and about 50 other sites, except sigma1 receptors (1.6
nM). L 745,870 similarly showed selectivity for hD4 (2.5 nM) vs. hD2 (905 nM) and
hD3 (> 3000 nM) receptors. In contrast, raclopride displayed low affinity at hD4
(> 3000 nM) vs. hD2 (1.1 nM) and hD3 receptors (1.4 nM). Stimulation of [35S]
GTPgammaS binding at hD4 receptors by dopamine (DA) was blocked by S 18126 and L
745,870 with Kb values of 2.2 and 1.0 nM, respectively, whereas raclopride (>
1000 nM) was inactive. In contrast, raclopride inhibited stimulation of [35S]
GTPgammaS binding at hD2 sites by DA with a Kb of 1.4 nM, whereas S 18126 (> 1000
nM) and L 745,870 (> 1000 nM) were inactive. As concerns presynaptic dopaminergic
receptors, raclopride (0.01-0.05 mg/kg s.c. ) markedly enhanced DA synthesis in
mesocortical, mesolimbic and nigrostriatal dopaminergic pathways. In contrast,
even high doses (2. 5-40.0 mg/kg s.c.) of S 18126 and L 745,870 were only weakly
active. Similarly, raclopride (0.016 mg/kg i.v.) abolished inhibition of the
firing rate of ventrotegmental dopaminergic neurons by apomorphine, whereas even
high doses (0.5 mg/kg i.v.) of S 18126 and L 745,870 were only weakly active. As
regards postsynaptic dopaminergic receptors, raclopride potently (0.01-0.3 mg/kg
s.c.) reduced rotation elicited by quinpirole in rats with unilateral lesions of
the substantia nigra, antagonized induction of hypothermia by PD 128, 907,
blocked amphetamine-induced hyperlocomotion and was effective in six further
models of potential antipsychotic activity. In contrast, S 18126 and L 745,870
were only weakly active in these models (5.0-> 40.0 mg/kg s.c.). In six models of
extrapyramidal and motor symptoms, such as induction of catalepsy, raclopride was
likewise potently active (0.01-2.0 mg/kg s.c.) whereas S 18126 and L 745,870 were
only weakly active (10.0-80.0 mg/kg s.c.). In freely moving rats, raclopride
(0.16 mg/kg s.c.) increased levels of DA by + 55% in dialysates of the frontal
cortex. However, it also increased levels of DA in the accumbens and striatum by
70% and 75%, respectively. In contrast to raclopride, at a dose of 0.16 mg/kg
s.c. , neither S 18126 nor L 745,870 modified frontal cortex levels of DA.
However, at a high dose (40.0 mg/kg s.c.), S 18126 increased dialysate levels of
DA (+ 85%) and noradrenaline (+ 100%), but not serotonin (+ 10%), in frontal
cortex without affecting DA levels in accumbens (+ 10%) and striatum (+ 10%). In
conclusion, S 18126 and L 745,870 behave as potent and selective antagonists of
cloned, hD4 vs. other dopaminergic receptor types in vitro. However, their in
vivo effects at high doses probably reflect residual antagonist actions at D2 (or
D3) receptors. Selective blockade of D4 receptors was thus associated neither
with a modification of dopaminergic transmission nor with antipsychotic
(antiproductive) or extrapyramidal properties. The functional effects of
selective D4 receptor blockade remain to be established.
PMID- 9765337
TI - A comparative in vitro and in vivo pharmacological characterization of the novel
dopamine D3 receptor antagonists (+)-S 14297, nafadotride, GR 103,691 and U
99194.
AB - The benzofurane (+)-S 14297, the benzamide nafadotride, the aminoindane U 99194
and the arylpiperazine GR 103,691 have been proposed as "selective" antagonists
at dopamine D3 vs. D2 receptors. Herein, we compared their in vitro affinities
and in vivo actions to those of the aminotetralin D3 antagonists (+)-AJ 76 and
(+)-UH 232. Affinities at recombinant, human (h)D3 and/or hD2 sites were
determined by employing the mixed D2/D3 antagonist [125I]-iodosulpride and the
preferential D3 ligands [3H]-(+)-PD 128, 907 and [3H]-(+)-S 14297. [3H]-(+)-PD
128,907, [3H]-(+)-S 14297 and [125I]-iodosulpride yielded an essentially
identical pattern of displacement at D3 sites, which suggests that they recognize
the same population of receptors. The rank order of potency (Ki values in nM vs.
[3H]-(+)-PD 128,907) was GR 103,691 (0.4) approximately nafadotride (0.5) >
haloperidol (2) approximately (+)-UH 232 (3) approximately (+)-S 14297 (5) > (+)
AJ 76 (26) > U 99194 (160). The rank order of preference (Ki ratio, D2:D3) for D3
receptors (labeled by [3H]-PD 128,907) vs. D2 sites (labeled by [125I]
iodosulpride) was (+)-S 14297 (61) approximately GR 103,691 (60) > U 99194 (14) >
nafadotride (9) approximately (+)-UH 232 (8) approximately (+)-AJ 76 (6) >
haloperidol (0.2). (+)-S 14297 and GR 103,691 also showed greater than 100-fold
selectivity at dopamine hD3 vs. hD4 and hD1 sites. However, GR 103,691 showed
marked affinity for serotonin1A receptors (5.8 nM) and alpha-1 adrenoceptors
(12.6 nM). In vivo, all antagonists except GR 103,691 prevented the induction of
hypothermia by (+)-PD 128,907 (0.63 mg/kg s.c.) and a further preferential D3
agonist, (+)-7-OH-DPAT (0.16 mg/kg s.c.). On the other hand, haloperidol, (+)-AJ
76, (+)-UH 232 and nafadotride all induced catalepsy in rats, whereas (+)-S
14297, U 99194 and GR 103,691 were inactive. Haloperidol, (+)-AJ 76, (+)-UH 232,
nafadotride and (weakly) U 99194 also enhanced prolactin secretion and striatal
dopamine synthesis, whereas (+)-S 14297 and GR 103,691 were inactive. However,
despite its high affinity at 5-HT1A receptors and alpha-1 adrenoceptors, both of
which are present on raphe-localized serotonergic neurons, GR 103,691 (0.5 mg/kg
i.v.) failed to influence their basal firing rate or the inhibition of their
electrical activity by the 5-HT1A agonist (+/-)-8-OH-DPAT (0.005 mg/kg i.v.), a
result that casts doubt on its activity in vivo. In conclusion, both (+)-S 14297
and GR 103,691 are markedly selective ligands that permit the characterization of
actions at hD3 vs. hD2 receptors in vitro, but (+)-S 14297 appears to be of
greater utility for the evaluation of their functional significance in vivo.
Nevertheless, to develop a better understanding of the respective roles of
dopamine D3 and D2 receptors, we need additional, chemically diverse antagonists
of improved potency and selectivity.
PMID- 9765338
TI - Substituted 3beta-phenylethynyl derivatives of 3alpha-hydroxy-5alpha-pregnan-20
one: remarkably potent neuroactive steroid modulators of gamma-aminobutyric acidA
receptors.
AB - Neuroactive steroids are positive allosteric modulators of gamma-aminobutyric
acidA (GABAA) receptor complexes. Synthetic modification generally does not
increase neuroactive steroid potency beyond that of the naturally occurring
progesterone metabolite, 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha,5alpha-P).
Recently, it has been shown that introduction of appropriately para-substituted
phenylethynyl groups at the 3beta-position of 5beta steroids increases receptor
potency. The present report presents the synthesis and pharmacological profile of
an analogous series of 5alpha steroids. The most striking feature of this series
is the further enhancement of in vitro and in vivo potency obtained. In
particular, 3beta-(p-acetylphenylethynyl)-3alpha-hydroxy-5alpha-pr egnan-20-one
(Co 152791) was 11-, 16- and 49-fold more potent than 3alpha, 5alpha-P in
modulating the binding of [35S]TBPS, [3H]flunitrazepam and [3H]muscimol,
respectively, in rat brain membranes (Co 152791 IC50 or EC50 = 2-7.5 nM).
Similarly, Co 152791 was 3- to 20-fold more potent than 3alpha,5alpha-P as an
inhibitor of [35S]TBPS binding in human recombinant receptor combinations
containing alpha1, alpha2, alpha3 or alpha5 and beta2gamma2L subunits (Co 152791
IC50 1.4-5.7 nM). Co 152791 displayed low efficacy and 3alpha,5alpha-P had low
potency at alpha4/6beta3gamma2L GABAA receptor complexes. Interestingly, Co
152791 demonstrated remarkable potency as a potentiator of GABA-evoked currents
in Xenopus oocytes expressing alpha1beta2gamma2L receptors (EC50 0.87 nM), being
184-fold more potent than 3alpha,5alpha-P. High in vitro potency was also
reflected in enhanced in vivo activity in that Co 152791 exhibited exceptional
anticonvulsant potency, protecting mice from pentylenetetrazol-induced seizures
at a approximately 5-fold lower dose than 3alpha,5alpha-P after i.p.
administration (Co 152791 ED50 0.6 mg/kg). Moreover, Co 152791 was orally active
(ED50 1.1 mg/kg) and exhibited a therapeutic index of 7 relative to rotorod
impairment. The remarkable potency of Co 152791 as a positive allosteric
modulator of GABAA receptors may be explained by its interaction with an
auxiliary binding pocket in the neuroactive steroid binding site. In addition,
modification at the 3beta-position probably hinders metabolism of the 3alpha
hydroxy group contributing to the exceptional anticonvulsant potency of this
compound relative to other neuroactive steroids.
PMID- 9765339
TI - Structural requirements for the hepatotoxicity of nonsteroidal anti-inflammatory
drugs in isolated rat hepatocytes.
AB - Hepatotoxicity is one of the common side effects of nonsteroidal anti
inflammatory drugs (NSAIDs). We investigated the cytotoxicity of 18 acidic NSAIDs
(3 salicylic acids, 3 anthranilic acids, 6 arylacetic acids, 6 arylpropionic
acids) to freshly isolated rat hepatocytes as assessed by the NSAID-induced
leakage of lactate dehydrogenase (LDH) in order to determine structural
requirements for the direct hepatotoxicity of the NSAIDs. Diflunisal (salicylic
acids), flufenamic acid, mefenamic acid, tolfenamic acid (anthranilic acids),
diclofenac, indomethacin, acemetacin (arylacetic acids) and flurbiprofen
(arylpropionic acids) caused significant LDH leakage, indicating that substituent
position of a carboxyl group does not relate to the hepatotoxicity of the NSAIDs.
Because the cytotoxic NSAIDs were of two types as classified by their "skeleton,"
diphenyl and diphenylamine, we tested the cytotoxicity of the compounds. Diphenyl
did not cause LDH leakage, but diflunisal, which has the diphenyl structure, was
cytotoxic. On the other hand, diphenylamine induced LDH leakage to the same
degree as diclofenac, which has the diphenylamine structure. Therefore,
diphenylamine itself was suggested to be responsible for the cytotoxicity of
diclofenac and anthranilic acids, whereas a substituted group(s) in addition to
diphenyl structure seems to be important for diflunisal cytotoxicity. All of the
cytotoxic NSAIDs and diphenylamine extensively decreased hepatocellular ATP
content, whereas the noncytotoxic NSAID did not, indicating that the NSAID
induced decrease in ATP, probably by their uncoupling effects on mitochondrial
oxidative phosphorylation, is involved in the hepatotoxicity of the NSAIDs.
PMID- 9765340
TI - A novel cardiotonic agent SCH00013 acts as a Ca++ sensitizer with no chronotropic
activity in mammalian cardiac muscle.
AB - We investigated the inotropic effect of SCH00013 (4, 5-dihydro-6-[1-[2-hydroxy-2
(4-cyanophenyl)ethyl]-1,2,5, 6-tetrahydropyrido-4-yl]pyridazin-3(2H)-one) on
isolated dog and rabbit ventricular muscles and in indo-1 loaded rabbit
ventricular cardiomyocytes. SCH00013 elicited a positive inotropic effect in a
concentration-dependent manner (10(-6) to 10(-4) M) in both species in the
presence of bupranolol. The positive inotropic effects of 10(-4) M SCH00013 on
the dog and rabbit were 38% and 29% of the maximal response to isoproterenol.
SCH00013 did not alter the rate of beating in isolated rabbit right atria. In
indo-1 loaded rabbit ventricular cardiomyocytes, SCH00013 at 10(-4) M increased
the systolic cell shortening by 52% above the base-line value in association with
an insignificant increase in the systolic fluorescence ratio by 15% above the
control. SCH00013 shifted the relationship between the Ca++ transients and cell
shortening to the left as compared with that of elevation of [Ca++]o. In the dog
and rabbit ventricular muscles, carbachol partially inhibited the positive
inotropic effect of SCH00013. SCH00013 did not affect the positive inotropic
effect of isoproterenol at 3 x 10(-6) M, but enhanced it at 3 x 10(-5) M. These
results indicate that SCH00013 is a cardiotonic agent that primarily acts via an
increase in myofibrillar Ca++ sensitivity with a moderate contribution of the
cAMP-dependent mechanism at higher concentrations. SCH00013 has no chronotropic
activity. The pharmacological profile of SCH00013 implies that the compound may
be a promising cardiotonic agent for the treatment of congestive heart failure.
PMID- 9765341
TI - Modulation by angiotensin II of isoproterenol-induced cAMP production in
preglomerular microvascular smooth muscle cells from normotensive and genetically
hypertensive rats.
AB - The objectives of the present study were to determine whether angiotensin II (Ang
II) modifies beta-adrenoceptor-induced cAMP production in preglomerular
microvascular smooth muscle cells (PMVSMCs), to determine whether the Ang II/beta
adrenoceptor interaction on cAMP production differs in PMVSMCs from normotensive
Wistar-Kyoto (WKY) rats vs. PMVSMCs from spontaneously hypertensive rats (SHR),
and to elucidate the mechanism of Ang II/beta-adrenoceptor interactions on cAMP
production in PMVSMCs. In cultured PMVSMCs, isoproterenol increased cAMP levels
and this effect was markedly enhanced by Ang II. The Ang II enhancement of
isoproterenol-induced cAMP was significantly greater in SHR PMVSMCs compared with
WKY PMVSMCs. Neither inhibition of calcineurin with FK506, inhibition of calcium
calmodulin with W-7 and calmidazolium, nor inhibition of Gi proteins with
pertussis toxin attenuated Ang II enhancement of isoproterenol-induced cAMP in
PMVSMCs from either SHR or WKY rats. Moreover, the effect of Ang II on
isoproterenol-induced cAMP was not mimicked by alpha-2 adrenoceptor stimulation.
In contrast, chelation of intracellular calcium with BAPTA-AM attenuated,
increasing intracellular calcium with A23187 augmented, and inhibition of protein
kinase C with either calphostin C or chelerythrine chloride abolished Ang II
enhancement of isoproterenol-induced cAMP. We conclude that in cultured PMVSMCs
Ang II enhances the cAMP response to beta-adrenoceptor agonists via a mechanism
that involves coincident activation of adenylyl cyclase by stimulatory G proteins
and protein kinase C. Thus, protein kinase C-mediated activation of adenylyl
cyclase may attenuate Ang II-induced vasoconstriction in the renal
microcirculation by raising the intracellular levels of cAMP, and this mechanism
may be augmented in genetic hypertension.
PMID- 9765342
TI - Blockade of N- and P/Q-type calcium channels reduces the secondary heat
hyperalgesia induced by acute inflammation.
AB - High voltage calcium channels are implicated in nociceptive transmission after
nerve injury, capsaicin or formalin injection. The purpose of this study was to
investigate the role of calcium channels in secondary heat hyperalgesia
associated with acute joint inflammation. After induction of acute inflammation
(knee joint injection of kaolin and carrageenan), decreased paw withdrawal
latency (PWL) to radiant heat (i.e., secondary heat hyperalgesia), increased
guarding of the limb and increased joint circumference occurs. Spinal
administration (through a microdialysis fiber placed in dorsal horn) of an N-type
calcium channel blocker (MVIIA, SNX 111, ziconotide, 0.001-0.1 mM), before
induction of inflammation, prevents the decrease in PWL. Treatment with SNX 111 4
hr after inflammation reverses heat hyperalgesia. A small reduction in
spontaneous pain-related behaviors (guarding of the limb) occurs after pre- or
post-treatment with SNX 111. Spinal blockade of P/Q-type calcium channels (with
omega-agatoxin IVA) had no effect on the decrease in PWL to radiant heat when
administered after induction of inflammation. However, pre-treatment with omega
agatoxin IVA prevents secondary heat hyperalgesia. omega-Agatoxin IVA has no
effect on spontaneous pain-related behaviors whether administered before or after
induction of inflammation. In contrast, pre or post-treatment with nifedipine (L
type calcium channel blocker, 0.01-1.0 mM), had no effect on heat hyperalgesia or
spontaneous pain-related behaviors induced by acute inflammation. There were no
differences in joint circumference between groups with any treatment. Thus, N
type calcium channels contribute to both the development and maintenance of
secondary heat hyperalgesia while P-type calcium channels are only involved
during development of hyperalgesia.
PMID- 9765343
TI - Renal excretory responses produced by the delta opioid agonist, BW373U86, in
conscious rats.
AB - Studies were performed in conscious Sprague-Dawley rats to characterize the
changes in renal excretory function produced by activation of delta opioid
systems. The intravenous infusion of 50 microgram/kg/min, BW373U86 (BW), a
nonpeptide delta opioid receptor agonist, produced a significant increase in
urine flow rate and urinary sodium excretion. The infusion of BW at a dose of 30
microgram/kg/min produced diuresis without affecting urinary sodium excretion. In
contrast, BW did not alter either renal excretory parameter at a dose of 10
microgram/kg/min. The renal responses produced by BW occurred without changes in
heart rate or mean arterial blood pressure. The diuretic and natriuretic
responses produced by the i.v. infusion of BW (50 microgram/kg/min) were
prevented by pretreatment of animals with the selective delta opioid receptor
antagonist, naltrindole (1 mg/kg, i.v.). When administered alone, naltrindole (1
mg/kg, i.v.) failed to change any systemic cardiovascular or renal excretory
parameter. In other groups of animals, the peripheral administration of the delta
opioid receptor agonist, SNC80, also evoked a profound diuretic and natriuretic
response (naltrindole sensitive) similar to that produced by BW. In contrast to
these findings, the diuretic and natriuretic response produced by BW infusion (30
or 50 microgram/kg/min, i.v.) was abolished in rats having undergone chronic
bilateral renal denervation. Together, these results demonstrate that the
peripheral administration of BW373U86 or SNC80 produce marked diuretic and
natriuretic responses in conscious Sprague-Dawley rats via a delta opioid
receptor pathway and that intact renal nerves are required for mediating these
responses. Although endogenous delta opioid systems do not appear to exert a
tonic influence under basal conditions, these findings suggest that delta opioid
pathways may evoke significant changes in renal excretory function under
conditions in which these systems are activated.
PMID- 9765344
TI - Effects of ketoconazole on the intestinal metabolism, transport and oral
bioavailability of K02, a novel vinylsulfone peptidomimetic cysteine protease
inhibitor and a P450 3A, P-glycoprotein dual substrate, in male Sprague-Dawley
rats.
AB - We investigated the effects of ketoconazole on the oral bioavailability of
morpholine-urea-phenylalanine-homophenylalanine-vinylsulfone-phenyl (K02), a
vinylsulfone peptidomimetic cysteine protease inhibitor, and a P450 3A (CYP3A)
and P-glycoprotein dual substrate, in male Sprague-Dawley rats, so as to evaluate
the roles of CYP3A and P-gp in K02 disposition. Male Sprague-Dawley rats (8-10 wk
old, n = 3-6) were administered a single dose of K02 (10 mg/kg) i.v. or (30
mg/kg) p.o. with or without a concomitant oral dose of ketoconazole (20 mg/kg).
Blood samples were collected from 2 min to 8 h after administration through a
implanted jugular vein cannula. K02 plasma concentrations were determined by
liquid chromatography/mass spectrometer/mass spectrometer analysis. Ketoconazole
markedly raised the area under the curve of orally administered K02 from 9.4 +/-
4.4 to 102 +/- 24 mg . min/liter and decreased K02 oral plasma clearance from
3810 +/- 1620 to 306 +/- 60 ml/min/kg. With concomitant ketoconazole dosing, the
changes of AUC of i.v. administered K02 (from 94 +/- 17 to 107 +/- 14 mg .
min/liter) and clearance (from 110 +/- 22 to 95 +/- 13 ml/min/kg) were not
significant, although K02 oral bioavailability increased from 2.9 +/- 1.4 to 31.0
+/- 7.5% (P < .001). In summary, ketoconazole, a dual inhibitor of CYP3A and P
glycoprotein, can effectively increase K02 oral bioavailability by inhibiting the
CYP3A/P-gp absorption barrier in the small intestine.
PMID- 9765345
TI - Characterization of cembranoid interaction with the nicotinic acetylcholine
receptor.
AB - The class of diterpenoids with a 14-carbon cembrane ring, the cembranoids,
includes both competitive and noncompetitive inhibitors of the nicotinic
acetylcholine receptor (AChR). All 20 coelenterate-derived cembranoids studied in
this report inhibited [piperidyl-3,4-3H]-phencyclidine ([3H]-PCP) binding to its
high-affinity site on the electric organ AChR, with IC50s ranging from 0.9 microM
for methylpseudoplexaurate to 372 microM for lophotoxin. Inhibition was complete
with all cembranoids but lophotoxin and most Hill coefficients were close to 1.
Methylpseudoplexaurate and [3H]-PCP binding was competitive.
Methylpseudoplexaurate and the fourth most potent cembranoid, eunicin, competed
with each other for [3H]-PCP displacement, indicating that there exist one or
more cembranoid sites on the AChR. Cembranoid affinity for the AChR correlated
with hydrophobicity, but was also dependent on other features.
Methylpseudoplexaurate and n-octanol also competed with each other for [3H]-PCP
displacement, indicating that the cembranoid site is linked to the n-octanol site
on the AChR. Unlike lophotoxin, the five cembranoids tested did not inhibit
[125I]Tyr54-alpha-bungarotoxin binding to the AChR agonist sites. All seven
cembranoids tested on oocyte-expressed electric organ AChR reversibly blocked
acetylcholine-induced currents, although the inhibitor concentration curves were
shallow and the inhibition was incomplete.
PMID- 9765346
TI - Gamma-hydroxybutyrate is a GABAB receptor agonist that increases a potassium
conductance in rat ventral tegmental dopamine neurons.
AB - gamma-Hydroxybutyric acid (GHB) is an abused substance that occurs naturally in
the basal ganglia. Electrophysiological recordings of membrane voltage and
current were made to characterize the effects of GHB on dopamine neurons in the
ventral tegmental area of the rat midbrain slice. Perfusate containing GHB caused
a concentration-dependent membrane hyperpolarization (EC50 = 0.88 +/- 0.21 mM)
and a reduction in input resistance (EC50 = 0.74 +/- 0.21 mM). The highest
concentration of GHB studied (10 mM) hyperpolarized neurons by 20 +/- 3 mV and
reduced input resistance by 58% +/- 9%. Changes in membrane potential and input
resistance were blocked by the gamma-aminobutyric acid antagonist CGP-35348 (300
microM), but neither bicuculline (30 microM) nor strychnine (10 microM) was an
effective antagonist. Voltage-clamp recordings demonstrated that GHB (1 mM)
evoked 80 +/- 6 pA of outward current (at -60 mV) that reversed at -110 mV (in
2.5 mM K+). Increasing concentrations of extracellular K+ progressively shifted
the reversal to more depolarized potentials. In tetrodotoxin (0.3 microM) and
tetraethylammonium (10 mM), depolarizing voltage steps (to -30 mV) evoked calcium
dependent current spikes that were completely blocked by GHB (1 mM). These data
suggest that GHB is an agonist at gamma-aminobutyric acid receptors and would be
expected to inhibit DA release by causing K+-dependent membrane
hyperpolarization.
PMID- 9765347
TI - F 11440, a potent, selective, high efficacy 5-HT1A receptor agonist with marked
anxiolytic and antidepressant potential.
AB - F 11440 (4-methyl-2-[4-(4-(pyrimidin-2-yl)-piperazino)-butyl]-2H, 4H-1,2,4
triazin-3,5-dione) was the outcome of a research effort guided by the hypothesis
that the magnitude of the intrinsic activity of agonists at 5-HT1A receptors
determines the magnitude of their antidepressant and anxiolytic-like effects. The
affinity of F 11440 for 5-HT1A binding sites (pKi, 8.33) was higher than that of
buspirone (pKi, 7.50), and somewhat lower than that of flesinoxan (pKi, 8.91). In
vivo, F 11440 was 4- to 20-fold more potent than flesinoxan, and 30- to 60-fold
more potent than buspirone, in exerting 5-HT1A agonist activity at pre- and
postsynaptic receptors in rats (measured by, for example, its ability to decrease
hippocampal extracellular serotonin (5-HT) levels and to increase plasma
corticosterone levels, respectively). F 11440 did not have detectable
antidopaminergic activity (unlike buspirone, which inhibited all of the directly
observable behavioral effects of methylphenidate in rats), showed no evidence of
antihistaminergic activity (unlike flesinoxan, which protected against the
effects of a histamine aerosol in guinea pigs), and had a 70-fold separation
between its 5-HT1A agonist and alpha-1 adrenergic antagonist properties (measured
as the ability to inhibit the methoxamineinduced increase in blood pressure in
rats), unlike flesinoxan, which showed a <3-fold separation. In HeLa cells
expressing human 5-HT1A receptors, F 11440 decreased the forskolin-induced
increase in AMP, and, based on its maximal effect, was found to have an intrinsic
activity of 1.0 relative to that of 5-HT, which was significantly higher than
that of buspirone (0.49), ipsapirone (0.46) and flesinoxan (0.93). Consistent
with the aforementioned hypothesis, F 11440 produced anxiolytic- and
antidepressant-like effects in animal models (i.e., increased punished responding
in a pigeon conflict procedure and decreased immobility in a rat forced swimming
test, respectively) that were more substantial than those of buspirone,
ipsapirone and flesinoxan. Thus, F 11440, shown here to be a potent, selective,
high efficacy 5-HT1A receptor agonist, appears to have the potential to exert
marked anxiolytic and antidepressant activity in humans.
PMID- 9765348
TI - Contribution of the opioid system to alcohol aversion and alcohol drinking
behavior.
AB - The effect of blocking delta opioid receptors on alcohol aversion was examined in
female alcohol-preferring (P) rats using a conditioned taste aversion (CTA)
paradigm. In experiment 1, alcohol naive P rats were given i.p injections of 0.5,
1.0 or 1.5 g alcohol/kg BW or saline, paired with consumption of a banana
flavored solution during 5 conditioning trials. Alcohol in a dose of 0.5 g/kg was
not aversive while the two higher doses (1.0 and 1.5 g/kg) were both aversive in
the CTA paradigm. In experiment 2, the effect of the selective delta opioid
receptor antagonist, naltrindole (NTI), on alcohol aversion was examined. Rats
were pretreated with NTI in doses of 2.5, 5.0, 10.0 or 20.0 mg/kg before
conditioning using the nonaversive dose of alcohol from Experiment 1. As in
experiment 1, the 0.5 g/kg dose of alcohol did not produce a CTA. Administration
of NTI alone in doses of 2.5, 5.0 or 10.0 mg/kg did not produce a CTA. However,
when the nonaversive dose of alcohol (0.5 g/kg) was combined with NTI in a dose
of either 5.0 or 10.0 mg/kg, an aversion to alcohol was seen. The highest dose of
NTI (20 mg/kg) produced a CTA when given either alone and in combination with
alcohol. The results indicate that blocking the action of opioid peptides at the
delta opioid receptor can make a nonaversive dose of alcohol aversive which
suggests that opioid peptides, acting via the delta opioid receptor, play an
important role in regulating alcohol aversion.
PMID- 9765349
TI - Blockage by terfenadine of the adenosine triphosphate (ATP)-sensitive K+ current
in rabbit ventricular myocytes.
AB - We examined the blocking effects of terfenadine, an antihistaminic agent, on the
ATP-sensitive K+ current (IK,ATP) in rabbit ventricular cells. IK,ATP was induced
by cromakalim or NaCN. Terfenadine blocked the IK,ATP with an IC50 of 1.7 microM
at -10 mV. This blockage was voltage dependent; depolarization induced a stronger
blockage. According to the transmembrane electrical field model, terfenadine
interacts with the site located 15 to 18% from the cytoplasmic membrane surface.
In line with the assumption that the binding site is near the cytoplasmic
surface, terfenadine applied to the cytoplasmic solution potently inhibited the
single-channel activity for IK,ATP in the inside-out configuration (IC50 0.19
microM). In contrast, terfenadine applied to the external solution did not affect
the channel activity in the cell-attached configuration, but inhibited it when
applied into the pipette. The inhibition of the single channels by terfenadine
was accompanied by flickering of the channels. These findings suggest that 1)
terfenadine blocks the ATP-sensitive K+ channel in the open state, 2) the binding
site is near the internal membrane surface and 3) terfenadine is poorly
diffusible into the lipid biomembrane and accesses the binding site via the
hydrophilic pathway. Terfenadine also inhibited the transient outward K+ current,
inward rectifier K+ current and E4031-sensitive rectifier K+ current. However,
the inhibition of these repolarization currents by terfenadine at 1 microM was
not sufficient to prolong the action potential duration significantly. Whereas,
terfenadine (1 microM) prolonged the action potential duration which had been
shortened by cromakalim. Terfenadine may modify the ischemia-induced arrhythmias
by blocking IK,ATP.
PMID- 9765350
TI - Effects of novel anti-inflammatory compounds on healing of acetic acid-induced
gastric ulcer in rats.
AB - Nonsteroidal anti-inflammatory drugs often cause development of significant GI
lesions. Selective inhibitors of prostaglandin G/H synthase/cyclooxygenase-2
(PGHS-2) enzyme and some dual inhibitors of PGHS/5-lipoxygenase (5-LO) enzymes
have been reported to be potent anti-inflammatory compounds that carry a much
lower risk of having GI irritating effects. We have evaluated the anti
inflammatory effect and the GI safety profile of three new anti-inflammatory
compounds: the selective PGHS-2 inhibitors NS-398 and PD 138387 and the PGHS/5-LO
dual inhibitor PD 137968. All the compounds tested showed an anti-inflammatory
activity in the carragenan footpad edema test in rats. None of these compounds
caused either gastric damage 4 h after p.o. administration of 100 mg/kg in rats
or inhibition of PGE2 synthesis in the stomach. However, when administered p.o.
at an effective anti-inflammatory dose to rats with pre-existing acetic acid
induced gastric ulcer, NS-398 caused a statistically significant delay of ulcer
healing. No impairment of the ulcer healing was observed with the other compounds
evaluated. Derivatives of 2,6-di-tert-butylphenol, whose members may act as PGHS
1/PGHS-2 inhibitors, selective PGHS-2 inhibitors or PGHS/5-LO dual inhibitors,
are novel anti-inflammatory compounds that are devoid of GI irritating effects
and do not affect the rate of pre-existing gastric ulcer healing.
PMID- 9765351
TI - A neurotensin receptor antagonist inhibits acute immobilization stress-induced
cardiac mast cell degranulation, a corticotropin-releasing hormone-dependent
process.
AB - Stress worsens certain disorders such as migraines or asthma, and has also been
implicated in sudden myocardial arrest. It was previously shown that acute
psychological stress by immobilization results in dura mast cell degranulation,
an effect blocked by pretreatment with antiserum against corticotropin-releasing
hormone (CRH). Moreover, CRH was recently shown to induce skin mast cell
degranulation. The effect of psychological stress was investigated on rat cardiac
mast cells, because their release of coronary constrictive and proinflammatory
molecules contributes to myocardial ischemia and possibly arrhythmias.
Immobilization of rats for 30 min induced maximal cardiac mast cell degranulation
as evidenced by light and electron microscopy. This effect was inhibited by
pretreatment with the "antiallergic" drug sodium cromoglycate (cromolyn), which
is thought to act primarily through mast cell stabilization. Mast cell
degranulation was also blocked by preincubation with antiserum against CRH and
was partially inhibited by a CRH type-1 receptor selective antagonist. Sensory
neuropeptides did not appear to influence this effect, but a nonpeptide
neurotensin receptor antagonist blocked stress-induced cardiac mast cell
degranulation. This finding supports the involvement of neuropeptide neurotensin
which is present in the heart and is known to trigger mast cell degranulation.
These results indicate acute stress could result in local CRH and nonpeptide
neurotensin release which could contribute to myocardial pathophysiology through
direct or indirect release of cardiac mast cell mediators.
PMID- 9765352
TI - The antiproliferative and cell cycle effects of 5,6,7, 8-tetrahydro-N5,N10
carbonylfolic acid, an inhibitor of methylenetetrahydrofolate dehydrogenase, are
potentiated by hypoxanthine.
AB - 5,6,7,8-Tetrahydro-N5,N10-carbonylfolic acid (LY354899) has been demonstrated to
inhibit the dehydrogenase activity of C1-tetrahydrofolate synthase. This compound
was only moderately antiproliferative toward CCRF-CEM lymphocytic leukemia cells
in culture, but induced apoptosis after long incubation times. Slightly greater
potency was observed in CEM cells adapted to grow in low folate media. Cell cycle
alterations induced by LY354899 were unique relative to antifolates that inhibit
either the purine or thymidine de novo biosynthetic pathways. Based on the
observed changes in DNA content, we hypothesized that inhibition of the
dehydrogenase resulted in two temporally distinct events: the first was a
purineless-like effect and the second was a thymineless-like effect that resulted
in apoptosis. To test this hypothesis, we combined LY354899 with the purine
salvage metabolite, hypoxanthine. This combination resulted in an earlier and
more dramatic apoptotic response, indicating that the thymineless effect had been
potentiated. Biochemical analysis of ribo- and deoxyribonucleoside triphosphates
confirmed that inhibition of the dehydrogenase activity initially resulted in
decreased pools of deoxypurines and deoxypyrimidines, followed 16 hr later by an
increase in deoxyadenosine triphosphate (dATP) and a further decrease in
deoxythymidine triphosphate (dTTP). These studies demonstrate that the inhibition
of the dehydrogenase activity of C1-tetrahydrofolate synthase may represent a
viable target for the development of novel antifolates. The results are discussed
in terms of deoxypurine and deoxypyrimidine biosynthesis.
PMID- 9765353
TI - Delta opioid peptide [D-Ala2,D-leu5]enkephalin blocks the long-term loss of
dopamine transporters induced by multiple administrations of methamphetamine:
involvement of opioid receptors and reactive oxygen species.
AB - Delta opioid peptide [D-Ala2,D-leu5]enkephalin (DADLE) can prolong organ
preservation and increases myocardial tolerance to ischemia. Our study examined
the protective property of DADLE against methamphetamine- (METH) induced
dopaminergic terminal damage in the central nervous system. Because the
neurotoxicity of METH involves reactive oxygen species, we also examined if DADLE
might be an antioxidative agent in vitro. DADLE at 2 and 4 mg/kg (i.p.), given 30
min before each METH administration (5 or 10 mg/kg, i.p., four injections in a
day at 2-hr intervals), dose-dependently blocked the METH-induced long-term
dopamine transporter loss. The opioid antagonist naltrexone blocked this action
of DADLE in both aspects of striata but tends not to affect the effects of DADLE
in the nucleus accumbens. DADLE did not alter changes in body temperature induced
by METH. The reduction of striatal dopaminergic content and tyrosine hydroxylase
activity caused by METH, however, were not blocked by DADLE. In vitro, DADLE was
approximately equipotent to glutathione in inhibiting both superoxide anion
formation induced by xanthine oxidase and hydroxyl radical formation evoked by
ferrous/citrate complex. DADLE was only slightly less potent than glutathione in
inhibiting the iron/ascorbate-induced brain lipid peroxidation. These results
suggest that DADLE can protect the terminal membranes of dopaminergic neurons
against METH-induced insult but not the loss of dopaminergic content and tyrosine
hydroxylase activity and that this action of DADLE might involve opioid receptors
as well as the sequestration of free radical.
PMID- 9765354
TI - Differential effects of S6 mutations on binding of quinidine and 4-aminopyridine
to rat isoform of Kv1.4: common site but different factors in determining
blockers' binding affinity.
AB - Quinidine and 4AP are two nonspecific K channel blockers. Both block voltage
gated K channels from the intracellular side of the membrane and, in most cases,
binding is facilitated by channel activation. However, there are distinct
differences between quinidine and 4AP in the time- and voltage-dependencies of
drug-channel interaction. To learn about the molecular basis underlying the
similarities as well as differences in drug actions between quinidine and 4AP, we
used rKv1.4 (rat isoform of Kv1.4) as a model and studied: 1) Is there an overlap
between the binding sites of quinidine and 4AP? and 2) What factors are involved
in determining the binding affinity and kinetics of drug-channel interaction? Our
data show that mutations at a position in the S6 domain of rKv1.4 (position 529)
can cause dramatic and often opposite effects on quinidine and 4AP binding. For
quinidine, the degree of steric hindrance imposed by side chain at position 529
is an important factor in determining binding affinity. For 4AP, 529 mutations
that slow the rate of deactivation reduce binding affinity, probably due to a low
binding affinity in the open state. This, in conjunction with the observations
that 4AP binding is facilitated by channel activation, suggests that optimal 4AP
binding may occur in a transitional state between fully-closed and fully-open
states. In addition, hydrophobic interactions between blocker molecules and
residues at 529 tend to stabilize the binding of both quinidine and 4AP. Because
the S6 amino acid sequences are well conserved among many voltage-gated K
channels, our findings have general implications in understanding the structural
determinants of quinidine and 4AP binding to different K channels.
PMID- 9765355
TI - Protection from cadmium cytotoxicity by N-acetylcysteine in LLC-PK1 cells.
AB - N-acetylcysteine (NAC) has been known not only to stimulate synthesis of
glutathione but also to affect the gene regulation. In our study, effects of NAC
on the cytotoxicity of cadmium (Cd) were examined in LLC-PK1 cells. Preincubation
and subsequent incubation with 1 mM NAC almost completely suppressed Cd-induced
cellular damage evaluated either by trypan blue exclusion or lactate
dehydrogenase leakage. This almost complete protection required the presence of
NAC during Cd exposure. Treatment with 1 mM NAC increased the intracellular
glutathione level approximately 2-fold. Inhibition of this increase by buthionine
sulfoximine did not abolish the protection by NAC. One mM NAC also suppressed Cd
induced increase of c-Fos protein although NAC alone did not change the protein
content. The inhibition of transcriptions by actinomycin D did not affect the
protection by NAC. Thus, NAC-induced protection appeared to be independent of
glutathione level or the transcriptional activation of genes including c-fos.
However, treatment with NAC markedly lowered the uptake of Cd into cells although
it did not affect the efflux clearly. Addition of NAC during the exposure to Cd
suppressed Cd-induced cellular damage but the suppression decreased when the
duration of the exposure without NAC increased. These results suggest that NAC
induced protection against Cd cytotoxicity is mainly due to the lowered uptake of
Cd into the cells.
PMID- 9765356
TI - Down-regulation of the expression of three major rat liver cytochrome P450S by
endotoxin in vivo occurs independently of nitric oxide production.
AB - Endotoxemia results in both the down-regulation of multiple cytochrome P450 genes
and the induction of inducible nitric oxide synthase (NOS2). The nitric oxide
(NO) released during inflammation has been implicated as the mediator of the
decreased catalytic activity and expression of several cytochrome P450 isozymes.
We examined the role of NO in the decreases of both gene expression and activity
of three major P450s in the endotoxemic Fischer 344 rat. Endotoxin (LPS)
treatment suppressed both mRNA and protein expression of P450 2C11, 2E1, and 3A2.
Coadministration of the NOS inhibitor aminoguanidine to LPS-treated rats
completely inhibited the release of NO into the plasma but did not reverse the
down-regulation of expression of any of the P450s examined at three time points.
LPS treatment had a biphasic effect on some P450 catalytic activities. The
hydroxylation of testosterone at the 2alpha-, 16alpha- and to a lesser extent
6beta-positions, was inhibited 6 hr after LPS treatment and returned to normal by
12 hr. The role of NO in the 6 hr effects could not be assessed due to effects of
the aminoguanidine treatment itself. The second phase of decreased P450
activities seen after 24 hr was attributed to the NO-independent decrease in gene
expression. Our results suggest that NO is not required for the LPS-evoked down
regulation of P450 2C11, 2E1 and 3A2 mRNA or protein expression. We cannot rule
out a possible role for NO in the decreases in P450 activities seen early in the
response.
PMID- 9765357
TI - Differential effect of ethanol on PC12 cell death.
AB - Our goal was to examine the effects of ethanol on cell death using rat
pheochromocytoma (PC12) cells as a neuronal model. Withdrawal of serum for 24 hr
increased the number of PC12 cells labeled with ethidium homodimer indicating an
increase in cell death. Inclusion of 50 mM ethanol during the serum deprivation
further increased the amount of ethidium fluorescence by 39%. Although reducing
the serum concentration from the usual 15 to 4% did not alter cellular viability,
a significant increase in the amount of ethidium fluorescence was observed in
PC12 cells incubated for 24 hr in the presence of 4% serum and 150 mM ethanol. No
change in viability was observed in cells exposed to either 150 mM ethanol in the
presence of 15% serum or 50 mM ethanol in the presence of 4% serum. Inclusion of
ethanol during serum deprivation increased the amount of soluble DNA found in the
15,000 x g supernatant. Similarly, using the terminal deoxynucleotidyl
transferase dUTP nick-end labeling method to visualize DNA fragmentation in situ,
ethanol caused a 213% increase in the number of PC12 cells labeled during serum
withdrawal. Agarose gel electrophoresis of the DNA isolated from cells maintained
in the absence of serum yielded the classical DNA laddering pattern of 180 to 200
bp fragments suggestive of apoptosis. Ethanol caused a concentration-dependent
increase in the amount of DNA laddering in cells deprived of serum. Furthermore,
ethanol significantly potentiated the DNA laddering of cells maintained in 4%
serum. In contrast to the ethanol-induced increase in cell death when serum
factors were reduced or withdrawn, 150 mM ethanol lowered by 34% the number of
ethidium-labeled PC12 cells observed after a 30-min exposure to 2 mM H2O2.
Similarly, agarose gel electrophoresis of the DNA from H2O2-treated cells did not
display DNA laddering. This study demonstrates that: 1) ethanol antagonizes the
trophic action of serum factors; 2) pharmacologically relevant ethanol
concentrations significantly potentiate apoptosis after serum withdrawal and 3)
this enhancement appears specific for apoptosis.
PMID- 9765358
TI - Pharmacology and intracellular signaling mechanisms of the native human orphan
receptor BRS-3 in lung cancer cells.
AB - Neither the native ligand nor the cell biology of the bombesin (Bn)-related
orphan receptor subtype 3 (BRS-3) is known. In this study, we used RT-PCR to
identify two human lung cancer lines that contain sufficient numbers of native
hBRS-3 to allow study: NCI-N417 and NCI-H720. In both cell lines,
[DPhe6,betaAla11,Phe13, Nle14]Bn(6-14) stimulates [3H]inositol phosphate. In NCI
N417 cells, binding of 125I-[DTyr6,betaAla11,Phe13,Nle14]Bn(6-14) was saturable
and high-affinity. [DPhe6,betaAla11,Phe13,Nle14]Bn(6-14) stimulated phospholipase
D activity and a concentration-dependent release of [3H]inositol phosphate (EC50
= 25 nM) and intracellular calcium (EC50 = 14 nM); the increases in intracellular
calcium were primarily from intracellular stores. hBRS-3 activation was not
coupled to changes in adenylate cyclase activity, [3H]-thymidine incorporation or
cell proliferation. No naturally occurring Bn-related peptides bound or activated
the hBRS-3 with high affinity. Four different bombesin receptor antagonists
inhibited increases in [3H]inositol phosphate. Using cytosensor microphysiometry,
we found that [DPhe6,betaAla11,Phe13, Nle14]Bn(6-14) caused concentration
dependent acidification. The results show that native hBRS-3 receptors couple to
phospholipases C and D but not to adenylate cyclase and that they stimulate
mobilization of intracellular calcium and increase metabolism but not growth. The
discovery of human cell lines with native, functional BRS-3 receptors, of new
leads for a more hBRS-3-specific antagonist and of the validity of
microphysiometry as an assay has yielded important tools that can be used for the
identification of a native ligand for hBRS-3 and for the characterization of BRS
3-mediated biological responses.
PMID- 9765359
TI - Microsomal metabolism of delavirdine: evidence for mechanism-based inactivation
of human cytochrome P450 3A.
AB - Administration of delavirdine, an HIV-1 reverse transcriptase inhibitor, to rats
or monkeys resulted in apparent loss of hepatic microsomal CYP3A and delavirdine
desalkylation activity. Human CYP3A catalyzes the formation of desalkyl
delavirdine and 6'-hydroxy delavirdine, an unstable metabolite, while CYP2D6
catalyzes only desalkyl delavirdine. CYP2D6 catalyzed desalkyl delavirdine
formation was linear with time (up to 30 min) but when catalyzed by cDNA
expressed CYP3A4 or human liver microsomes the reaction rate declined
progressively with time. Coincubation with triazolam showed that delavirdine
caused a time- and NADPH-dependent loss of CYP3A4 activity in human liver
microsomes as measured by triazolam 1'-hydroxylation. The catalytic activity loss
was saturable and was characterized by a Ki of 21.6 +/- 8.9 microM and a kinact
of 0.59 +/- 0.08 min-1. An apparent partition ratio of 41 was determined with
cDNA expressed CYP3A4, based on the substrate depletion method. Incubation of
[14C]delavirdine with microsomes from several species resulted in irreversible
association with an approximately 50 kDa protein, as demonstrated by SDS
PAGE/autoradiography. Binding to the protein was NADPH dependent, glutathione
insensitive, proportional to the level of CYP3A expression and was inhibited by
ketoconazole, a specific CYP3A inhibitor. NADPH-dependent irreversible binding to
human and rat total microsomal protein was demonstrated following exhaustive
extraction of microsomal protein. Binding was decreased in the presence of
glutathione and appeared to be related to expression level of CYP3A. These
results suggest that delavirdine can inactivate CYP3A and has the potential to
slow the metabolism of coadministered CYP3A substrates.
PMID- 9765360
TI - Oxytocin inhibits the uptake of serotonin into uterine mast cells.
AB - The uptake of serotonin (5HT) into mouse uterine horns, the localization of sites
at which this amine could be stored and the effect of oxytocin on 5HT uptake were
studied. To analyze the characteristics of the 5HT uptake process, the tissue was
incubated with [3H]serotonin. The uptake of [3H]5HT was Na+ dependent and
saturable (Kmapp: 166 +/- 15 nM, Vmax: 404 +/- 25 fmol/mg tissue, 30 min
(diestrous); and Km: 165 +/- 39 nM, Vmax: 276 +/- 43 fmol/mg tissue, 30 min
(estrous), n = 6), and was inhibited by imipramine, fluoxetine and 6
nitroquipazine (IC50: 2; 0.09 and 0.5 nM, respectively). In the myometrium the
main 5HT uptake process was localized in uterine mast cells. This was determined
by treating the uterine horns with 6-hydroxydopamine, by using an
immunocytochemical approach and by studying the outflow of 3H under the action of
stimuli directed to either mast cells (compound 48/80: 10 microgram/ml) or
sympathetic nerves (high K+: 100 mM and veratridine: 20 microM) in uterine
preparations. Oxytocin inhibited [3H]5HT uptake into uterine mast cells during
estrus, but not in ovarectomized mice treated with progesterone. Maximal
inhibition was attained at 0.03 nM, with a significant reduction in both Kmapp
and Vmax (87 +/- 15 nM and 184 +/- 36 fmol/mg tissue/30 min, n = 3,
respectively). This effect was reversed by the addition of OVT16, an oxytocin
antagonist, at a concentration of 4 nM (Kmapp 158 +/- 35 nM, Vmax: 278 +/- 24
fmol/mg tissue, 30 min, n = 3). These findings support a new potential role of
oxytocin and mast cells as a local regulators of serotonin bioavailability in
myometrium. Because serotonin is recognized as an important endogenous uterotonic
compound, this effect could be considered as an indirect action of oxytocin that
may contribute to its potency as a labor inducer after genomic effects of
estrogens are expressed in uterine tissue.
PMID- 9765361
TI - Absorption enhancement, structural changes in tight junctions and cytotoxicity
caused by palmitoyl carnitine in Caco-2 and IEC-18 cells.
AB - Palmitoyl carnitine chloride (PCC) has been shown to be an effective enhancer of
intestinal transport of hydrophilic molecules. The exact mechanism by which the
epithelial barrier function is decreased is not clear. In an attempt to elucidate
the mechanism of action of PCC, we studied the relationship among absorption
enhancement, cell viability and tight junction protein localization in the human
colonic Caco-2 cell line and the rat small intestinal cell line IEC-18. Filter
grown cells were exposed to 0 to 1 mM PCC for 30 min, and the efficacy of PCC
treatment was determined by assessing the transepithelial electrical resistance
and the apparent permeability for mannitol and PEG-4000. Membrane lysis and
cytotoxicity were assessed by measurement of lactate dehydrogenase leakage and
uptake of propidium iodide and neutral red. The immunolocalization of the tight
junctional protein ZO-1 was quantified using CSLM and image-processing software.
In both cell lines, PCC caused a dose-dependent decrease in transepithelial
electrical resistance and a concomitant increase in the permeability for mannitol
and PEG-4000. The transport enhancement was accompanied by an increase in apical
membrane permeability and a reduction in cell viability. At higher PCC
concentrations (>/=0.4 mM), the distribution of the tight junctional protein ZO-1
was changed and cells were unable to recover viability. PCC is effective as an
absorption enhancer for hydrophilic macromolecules. However, lytic effects on the
cell membrane and reduced cell viability were concomitant with transport
enhancement.
PMID- 9765362
TI - Participation of nitric oxide in the mucosal injury of rat intestine induced by
ischemia-reperfusion.
AB - The dual role of nitric oxide as a cytoprotective or a cytotoxic free radical gas
has been noted in various types of pathophysiological conditions, including the
digestive system. The aim of this study was to examine the role of nitric oxide
in the mucosal injury induced by ischemia-reperfusion in the rat small intestine.
A transient intestinal ischemia was produced in the catheterized ileal segments
of rats by occluding the anterior mesenteric artery for 60 min. Nitric oxide
metabolites (NO2- and NO3-) and lactate dehydrogenase activity in perfusates of
the intestinal lumen were measured over 5 hr periods. The time-course of
histological changes in small intestine was also observed. After ischemia
reperfusion, nitric oxide release in the intestinal lumen increased significantly
and the dynamics of nitric oxide release correlated with that of lactate
dehydrogenase leakage. The administration of NG-nitro-L-arginine methyl ester
(1.0-2.5 mg/kg) inhibited this increased nitric oxide release and the lactate
dehydrogenase leakage and afforded protection against the mucosal injury induced
by ischemia-reperfusion. In conclusion, the nitric oxide production that was
accelerated by ischemia-reperfusion of small intestine may possibly participate
in the breakdown of intestinal mucosa after ischemia-reperfusion insult.
PMID- 9765363
TI - Targeted delivery of plasmid DNA to hepatocytes in vivo: optimization of the
pharmacokinetics of plasmid DNA/galactosylated poly(L-lysine) complexes by
controlling their physicochemical properties.
AB - In vivo receptor-mediated targeting of plasmid DNA to hepatocytes was achieved
through optimizing the physicochemical and pharmacokinetic properties of a
plasmid DNA/carrier complex. Galactosylated poly(L-lysine) (Gal-PLL) was
synthesized using PLL with a molecular weight of 1,800, 13,000 or 29,000 without
loss of the cationic charge. Plasmid DNA encoding chloramphenicol
acetyltransferase was complexed with each Gal-PLL. A larger amount of PLL1800 is
required for the complex formation than with PLL13000 and PLL29000, and
increasing the number of galactose units on Gal-PLL resulted in reduced binding
to plasmid DNA. The particle size and zeta-potential of the complexes varied
depending on the mixing ratio and Gal-PLL used. Then, plasmid DNA/Gal-PLL
complexes having diameters of 200 nm or less and a weak negative charge were
prepared. After i.v. injection of [32P]plasmid DNA/Gal13-PLL13000 and
[32P]plasmid DNA/Gal26-PLL29000, almost 80% of the radioactivity rapidly
accumulated in the liver, preferentially in the parenchymal cells. The hepatic
uptake clearances (CLliver) were much greater than any of the other tissue uptake
clearances. Compared with these complexes, [32P]plasmid DNA/Gal5-PLL1800 and
[32P]plasmid DNA/Gal5-PLL13000 had a smaller CLliver, suggesting that both the
molecular weight of PLL and the degree of galactose modification determine the
hepatic targeting of plasmid DNA. In vitro and in vivo gene expression studies
revealed that plasmid DNA/Gal13-PLL13000 and plasmid DNA/Gal26-PLL29000 complexes
are superior to plasmid DNA/Gal5-PLL1800 complex for introducing DNA into cells.
These results demonstrated that an optimal design of a DNA/carrier complex based
on physicochemical properties and a pharmacokinetic analysis of the distribution
properties leads to successful in vivo gene delivery.
PMID- 9765364
TI - Characterization and purification of the bovine adrenal angiotensin IV receptor
(AT4) using [125I]benzoylphenylalanine-angiotensin IV as a specific photolabel.
AB - The Ang IV receptor, AT4, has been shown to play important roles in various
mammalian tissues. In this study, structural properties of the AT4 receptor from
bovine adrenals are described using a novel photoactive analog of Ang IV,
[125I]Benzoylphenylalanine-Ang IV (BP-Ang IV), recently developed in our
laboratory. [125I]BP-Ang IV is identical to Ang IV with regards to binding
specificity and affinity and is easily cross-linked to the AT4 receptor under UV
light, thus greatly facilitating the structural analysis of the AT4 receptor by
SDS-PAGE. Comparisons between the native, reduced and nonreduced forms of the AT4
receptors by SDS-PAGE revealed that this receptor consists of multiple subunits.
The subunit containing the Ang IV binding site (designated as the alpha subunit)
has a molecular weight of approximately 165 kDa and contained approximately 20% N
linked carbohydrates. A subunit similar to the adrenal alpha subunit of the AT4
receptor was identified in all of the bovine tissues examined. Hippocampus and
aorta contained additional [125I]BP-Ang IV bound protein bands with molecular
weights of 150 and 125 kDa, respectively. Further, the alpha subunit was purified
to homogeneity using a method that integrates electrofractionation with
conventional protein purification techniques.
PMID- 9765365
TI - Depletion of protein kinase C-alpha by antisense oligonucleotides alters beta
adrenergic function and reverses the phorbol ester-induced reduction of
isoproterenol-induced adenosine 3'-5'-cyclic monophosphate accumulation in murine
Swiss 3T3 fibroblasts.
AB - Beta-adrenergic agonists are well known to increase the activity of adenylate
cyclase, yielding increases of the intracellular concentration of cAMP. It has
been reported that activation of protein kinase C (PKC) by phorbol esters reduces
the amplitude of isoproterenol-induced cAMP production in a 3T3-L1 cell line. In
this study, we investigated whether PKC-alpha is involved in this process in
murine Swiss 3T3 fibroblasts. A 20-mer phosphorothioate oligonucleotide designed
to hybridize to the AUG initiation codon of the murine PKC-alpha mRNA, which
contains 2'-O-methoxyethyl modifications incorporated into the 5' and 3' segments
of the oligonucleotide, was used to assess the putative role of PKC-alpha in the
beta-adrenergic receptor regulation. ISIS 14012 reduced PKC-alpha mRNA for over
72 hr after the initial treatment and the reduction was concentration dependent,
whereas the mismatch control, ISIS 13818, had no effect. This depletion was found
to be selective; ISIS 14012 had no effect on the mRNA expression of PKC-delta and
PKC-zeta. ISIS 14012 reduced in a time and concentration-dependent fashion the
levels of immunoreactive PKC-alpha protein by over 85% at 72 hr after treatment.
Depletion of PKC-alpha inhibited the effect of isoproterenol-induced cAMP
production by phorbol dibutyrate (PdBu). This finding is corroborated by the use
of a nonspecific inhibitor of PKC, GF-109203x, which also prevented the effect of
PdBu. Depletion of PKC-alpha by ISIS 14012 potentiated isoproterenol-induced cAMP
production in cells untreated with PdBu. However, neither depletion of PKC-alpha
nor PKC activation by a phorbol ester altered beta-adrenergic receptor affinity
and density. PKC activation by PdBu did not alter forskolin-induced cAMP levels,
but enhanced cAMP production by cholera toxin. PKC-alpha inhibition by ISIS 14012
had no effect on either cholera toxin-induced increases in cAMP or the acute
effects of phorbol esters on cholera toxin in induction of cAMP. Thus, PKC-alpha
appears to be involved in the regulation of beta-adrenergic receptor coupling to
adenylate cyclase, possibly by phosphorylating the Gs protein, but other PKC
isotypes must be involved in the effects observed when cells are treated with
cholera toxin.
PMID- 9765367
TI - Obituary
AB - Sheila Willmott, (1921-1998)CAB International and the Editor, Assistant Editor
and Editorial Board of the Journal of Helminthology wish to express their deepest
sympathy to the family and friends of Sheila Willmott who died on 8 May 1998
after a very short illness. Sheila served as Editor of the Journal of
Helminthology from 1980 to 1986.Dr Lotfi Khalil, formerly Deputy Director of the
International Institute of Parasitology at St Albans, worked closely with Sheila
and has written the following tribute.John W. Lewis, EditorSheila Willmott was a
leading contributor to the dissemination of parasitic information before the
development of computerization and information technology. She was born on 8
June, 1921, in London, and was educated at Tollington High School for Girls,
Chelsea Polytechnic and University College, London. She did her PhD at the London
School of Hygiene and Tropical Medicine under the supervision of Professor John
Buckley, the subject of her thesis being the study of amphistome digeneans. Her
studies were interrupted as a result of the Second World War when she was
'drafted' as a Rodent Instructor at the Ministry of Agriculture, Fisheries and
Food. After completing her PhD, she was appointed Assistant Lecturer in Zoology
at the University College of South Wales and Monmouthshire, Cardiff. In 1951,
Professor R.T. Leiper, the Director of the Bureau of Agricultural Parasitology
(Helminthology) recruited her as a Scientific Information Officer. She was
appointed Assistant Director of the Bureau in 1954, and Director in 1961, where
she stayed until her retirement in 1980.During her period as Director of the
Bureau, which was sited in the White House in the centre of St Albans, she
maintained and improved the high quality of Helminthological Abstracts and, in
1976, accepted the extra burden of starting and producing Protozoological
Abstracts. In 1979, she initiated and edited a primary journal, Systematic
Parasitology, devoted to papers on the taxonomy and systematics of parasites,
published by Junk. The activities of the Bureau were greatly expanded and she
initiated the taxonomic laboratories to provide a worldwide service for the
identification of animal helminths and plant-parasitic nematodes and to undertake
taxonomic research. A vast helminth reference collection was started, and the
Bureau became a recognized centre for the deposition of type specimens. The
library of the Bureau accumulated an enormous number of reference books, journals
and reprints, and provided a photocopying service supplying, at short notice,
copies of papers and publications. A number of books and other publications,
including the CIH Keys to the Nematode Parasites of Vertebrates, were produced
and edited by her and others. She also persuaded the Natural Environment Research
Council to finance the Fisheries Helminthology Unit which she established at the
Bureau in 1960, where it remained until it was transferred to Plymouth as part of
the Institute for Marine Environmental Research. The Bureau's name and status
were changed to the Commonwealth Institute of Helminthology, Commonwealth
Institute of Parasitology and, finally, the International Institute of
Parasitology.As Director, she travelled extensively and visited Commonwealth and
other countries, where she gave a number of seminars on information services and
the work of the Institute and the Commonwealth Agricultural Bureaux (CAB) as a
whole. She encouraged contact with Eastern Europe and visited Poland,
Czechoslovakia, Hungary, Bulgaria and the USSR. She initiated the system of
exchange publications with these countries, and this resulted in the exposure of
the literature from these countries to other research workers when abstracts of
these papers appeared in Helminthological Abstracts in English. Her links with
Eastern Europe resulted in her editing three volumes of taxonomic monographs
produced in English by Czech and Russian scientists. (ABSTRACT TRUNCATED)
PMID- 9765366
TI - Human vascular endothelial cells express functional nicotinic acetylcholine
receptors.
AB - ACh receptors sensitive to nicotine (nAChR) are present in human skin
keratinocytes and in bronchial epithelial cells. They are stimulated by ACh
secreted by the same cells that express them, and they modulate cell motility and
shape. A variety of non-neuronal tissues, including endothelial cells, synthesize
ACh, which raises the possibility that they are sensitive to nicotine. We
demonstrate here that endothelial cells that line blood vessels express
functional nAChRs. Their structure and ion-gating properties are similar to those
of the nAChRs expressed by ganglionic neurons and by skin keratinocytes and
bronchial epithelial cells. In situ hybridization experiments using primary
cultures of endothelial cells from human aorta demonstrated the presence in these
cells of the subunits believed to contribute to ganglionic ACh receptors (AChRs)
of the alpha3 subtype: alpha3, alpha5, beta2 and beta4. Binding of radiolabeled
epibatidine-a high-affinity specific ligand of certain neuronal AChRs, including
the alpha3 subtypes-revealed the presence of approximately 900 specific binding
sites per cell. We assessed the presence of functional AChRs by patch-clamp
experiments. Cultured human endothelial cells express ion channels that are
opened by (+)-anatoxin-a and are blocked by dihydro-beta-erythroidine. These are
specific agonist and antagonist, respectively, of neuronal AChRs of the alpha3
subtype. The ion-gating properties of the endothelial AChRs were similar to those
of neuronal ganglionic AChRs. The presence of AChRs sensitive to nicotine in
endothelial cells may be related to the toxic effects of nicotine on the vascular
system.
PMID- 9765368
TI - Antibody responses to fluke cysteine proteinases in Paragonimus- and Fasciola
infected rats.
AB - IgG and IgM antibody responses to fluke cysteine proteinases in Paragonimus
ohirai- and Fasciola sp.-infected rats were followed by means of cystatin capture
ELISA using fluke excretory-secretory products for 10 weeks after infection. The
specific IgG antibodies were detectable at week 2 postinfection in all P. ohirai
infected and some Fasciola-infected rats. Levels of specific IgG antibodies
increased rapidly between week 2 and 6, and slightly thereafter, in both infected
groups. From week 3, specific IgG antibody levels were higher in Fasciola
infected than P. ohirai-infected rats. Sera from infected rats did not react with
heterologous cysteine proteinases throughout the infection periods. In both
infected groups, the kinetic patterns of specific IgM antibody responses were
similar to those of specific IgG antibody responses although the ELISA levels of
the IgM antibody responses were much lower. In abnormal infections with P. ohirai
metacercariae x-irradiated at 2 krad, the specific IgG antibodies were detectable
at week 2 postinfection with similar ELISA values to normal P. ohirai infection,
but thereafter increased little. In infections with P. westermani, for which the
rat is not a suitable host, even stunted worms induced a comparable specific IgG
antibody response, although the response was lower than in normal infections with
P. ohirai. These results indicate that cystatin capture ELISA can distinguish
clearly between Paragonimus and Fasciola infections which show immunodiagnostic
cross-reactivity and is useful even in the early stages of the infection and in
the infection of unsuitable hosts.
PMID- 9765370
TI - The structuring process of the macroparasite community of an experimental
population of cichlasoma urophthalmus through time
AB - The structuring process of the macroparasite community of caged Cichlasoma
urophthalmus was studied over time using sentinel fish. Three thousand uninfected
cichlids were stocked in floating cages introduced into a quarry in which a wild
population of the same species was present. Caged and wild cichlids were sampled
monthly over 6 and 7 months, respectively. Seventeen macroparasite species were
found in the wild C. urophthalmus population, ten of which were detected in the
caged population after 6 months. Early infections were by those species that were
more frequent and abundant in the wild population, while helminths with a low
prevalence and abundance in the wild appeared later in the caged fish population.
The results suggested that the structuring process of the macroparasite community
of caged C. urophthalmus followed a predictable pattern, in which those species
that were most frequent and abundant in the wild were the first to establish in
sentinel fish.
PMID- 9765369
TI - Characterization of Fasciola hepatica redial generations by morphometry and
chaetotaxy under experimental conditions.
AB - Morphometric and chaetotactic studies were carried out on the body and cephalic
regions of the rediae of Fasciola hepatica (Trematoda: Fasciolidae) in order to
precisely identify the different redial generations of this trematode in Lymnaea
truncatula under experimental infection. At day 49 post-exposure at 20 degreesC,
the length of the redia was significantly higher in the first group of the first
generation (R1a) compared with successive generations, R1b, R2a and R2b/R3a. The
width of the body was similar in the R1a, R1b, and R2a rediae, but was
significantly lower in the R2b/R3a groups. The intrapharyngeal cavity of R1a
rediae was significantly wider compared with the R1b, R2a, and R2b/R3a groups,
whereas the pharyngeal wall was significantly thicker in the R2b/R3a rediae
compared with the R1b and R2a groups. Four other measurements, namely the maximum
length and width of the pharynx, diameter of the mouth, and width of intestine,
also showed significant variations in relation to pharyngeal morphology and age
of infection. Discriminant analysis based on these measurements demonstrated that
98% of the rediae were readily categorized into the four groups identified. The
number of perioral sensillae ranged from 126 to 160 but a significant difference
was only noted between the mean values of the first generation and those of the
group R2b/R3a. From these parameters, the maximum width of the pharyngeal lumen
was found to be the best characteristic in the identification of the redial
generations.
PMID- 9765371
TI - Comparison of the trapping ability of Arthrobotrys robusta and Monacrosporium
gephyropagum on infective larvae of Strongyloides papillosus.
AB - In an in vitro trial, the trapping ability of Arthrobotrys robusta and
Monacrosporium gephyropagum against Strongyloides papillosus infective larvae on
corn meal agar plates, was evaluated after seven days of interaction at 25
degrees C. Monacrosporium gephyropagum trapped 93.1% of the larvae whereas A.
robusta trapped only 32.3%. Variability in the capture of S. papillosus infective
larvae by both trapping fungi is discussed.
PMID- 9765372
TI - Surface ultrastructure of juvenile and adult stages of Centrocestus armatus.
AB - Centrocestus armatus (Trematoda: Heterophyidae) develops rapidly and produces
eggs at 3 days postinfection in albino rats. Excysted metacercariae are pear
shaped and concave ventrally, with 42-44 peg-like circumoral spines. The entire
body surface is densely covered with scale-like serrated spines. On juveniles,
serration of the tegumental spines is greatest in the middle of the ventral and
dorsal surfaces, and decreases anteriorly and posteriorly. Ciliated sensory
papillae are concentrated around the oral sucker. Several nonciliated sensory
papillae (type II papillae) occur equidistantly on the acetabulum and are
arranged in a linear symmetry on the dorsal surface. On adults, the serration of
the tegumental spines decreases to 14-17 tips on the ventrolateral surface. The
high density of tegumental spines on posterior half of the body and the
distribution of type II papillae on dorsal surface are considered to be
characteristic of C. armatus.
PMID- 9765373
TI - Helminth fauna of the Iberian lynx, Lynx pardinus.
AB - Specimens of 12 helminth species were collected from carcasses of eight Lynx
pardinus (Temminck, 1827), a carnivore endemic to the Iberian Peninsula. These
species included: Brachylaima sp. (12.5%) (Trematoda); Taenia pisiformis (12.5%),
T. polyacantha (25%), T. taeniaeformis (25%) and Mesocestoides litteratus (37.5%)
(Cestoda); Eucoleus aerophilus (12.5%), Ancylostoma tubaeforme (12.5%), Toxocara
cati (37.5%), Toxascaris leonina (62.5%), Vigisospirura potekhina potekhina
(12.5%), Mastophorus muris (12.5%) and Physaloptera praeputialis (12.5%)
(Nematoda). The helminth fauna in Iberian lynx is compared with that of L.
canadensis and L. rufus in America, and for L. lynx in Eurasia. The potential
relationships between the parasitological data and some geographical, historical
and dietary factors are discussed.
PMID- 9765375
TI - Ecology of proteocephalus torulosus in the blue bream (Abramis ballerus) fromthe
oder river on the borders of germany and poland
AB - During studies on the ecology of fish helminths, the tapeworm Proteocephalus
torulosus (Batsch, 1786) was frequently found in the intestine of the blue bream
(Abramis ballerus) from the Oder River (Germany/Poland). In total, 633 fish,
ranging between two and 16 years old, were sampled at monthly intervals over a
two year period during 1993-1995. Statistically significant differences in the
seasonal occurrence of the parasite in its fish host were observed. In 1993, the
prevalence remained at a high level, ranging between 61. 9 and 100%. During the
summer of 1994, this value decreased to 5.5% and remained low for the rest of the
year. The pattern of mean intensity of infection was similar to that of the
prevalence. In 1993, the mean intensity varied between 8.4 and 31.8 worms per
infected fish, with a continual loss of worms being observed in the summer of
1994. Changes in the amount of suspended particulate matter in water have been
identified as the main cause of these observed differences in the course of
infection of blue bream.
PMID- 9765374
TI - An erratic parasitism found in the lungs of sheep during experimental infection
with Fasciola gigantica (Japanese strain).
AB - An erratic parasitism was observed in the lungs of sheep experimentally infected
with Fasciola gigantica at autopsy 14 weeks after inoculation. Macroscopically,
several hyperaemia of 7.5-12.5 mm in diameter were found on the surface of the
lungs. Juvenile flukes detected in the lungs were much smaller than those in the
liver of the same sheep. A slight inflammatory reaction was observed in the lungs
and it is likely that the flukes had migrated in the pleural cavity for some
time. Occasionally, a mixed thrombus with many eosinophils was found in the blood
vessels adjacent to the bronchia, although no cough was observed clinically. This
suggests that diagnosis of juvenile fluke is difficult not only by
parasitological but also serological methods.
PMID- 9765376
TI - The use of video-imaging to assess the sub-lethal impact of plant secondary
compounds on Schistosoma mansoni miracidia.
AB - The study describes methods developed for using video-imaging technology to
record and measure the velocity of Schistosoma mansoni miracidia. The efficacy of
the classical bioassay procedure (a qualitative behavioural assay) was compared
with that of the new quantitative protocol, for assessing the sub-lethal impact
of a larvicidal dichloromethane extract of the seeds of Millettia thonningii on
miracidia. The new technique confirmed the efficacy of the classical bioassay for
rapid determination of the lethal and sub-lethal impact of larvicides but also
provided quantitative information on sub-lethal impacts on miracidial velocity
and shape.
PMID- 9765377
TI - Ultrastructure of the digestive and protonephridial systems of the metacercaria
of euclinostomum multicaecum
AB - The structure of the digestive tract of Euclinostomum multicaecum (Digenea:
Euclinostomatidae) is unusual, comprising several main lateral caeca which extend
posteriorly and further divide, giving rise to numerous smaller branches which
are widely distributed throughout the fluke. These multicaeca presumably promote
nutrient absorption during rapid and prolonged feeding directly following
excystment. The caecal wall consists of a syncytial gastrodermal epithelium,
bearing loop-like lamellae which extend into the lumen and enclose spherical
inclusion bodies and presumably also, increase the absorptive surface area. There
was no evidence of endo- or exocytosis, nor were lysosomes, phagosomes or
residual bodies observed. The gut caeca are supported by a fibrous basal lamina
and an underlying layer of muscle fibres, while parenchymal cells occupy much of
the extracellular space. The protonephridial system resembles that observed in
other digeneans consisting of flame cells and collecting ducts which join to form
a bladder that opens externally through a single excretory pore. The syncytial
epithelium of the collecting ducts is elevated by numerous lamellae while the
basal lamina is highly infolded. The luminal contents of these ducts comprise bar
shaped crystalline structures, lipid droplets and electron-dense inclusion
bodies. The excretory system is supported by a network of muscle fibres and
parenchymal cells.
PMID- 9765378
TI - Plagiorchis muris: recovery, growth and development in albino rats.
AB - Metacercariae of Plagiorchis muris, obtained from naturally infected dragonflies,
Sympetrum eroticum, successfully established in 4-week-old albino rats up to 14
days post-infection (p.i.) but by day 28 p.i. the recovery rate had significantly
decreased. The genital primordia in excysted metacercariae were differentiated
into those of metraterm, Mehlis' gland, ovary and cirrus pouch, with the
primordial testes appearing on day 1 p.i. The vitellaria and eggs in the uterus
were present in flukes on days 2 and 4 p.i., respectively. Mature flukes were
established in the lower part of the small intestine on day 5 p.i., with the peak
of egg production occurring on day 14 p.i. Growth of the flukes continued up to
day 28 p.i.
PMID- 9765380
TI - Intestinal helminth communities in the green lizard, lacerta viridis, from
bulgaria
AB - A data set comprising individual host/parasite lists from 100 Lacerta viridis
(Reptilia: Lacertidae) belonging to four isolated populations in Bulgaria was
studied. A total of seven helminth species was recovered (Leptophallus
nigrovenosus, Plagiorchis molini, Oswaldocruzia filiformis, Spauligodon
extenuatus, Skrjabinelazia hoffmanni, Physaloptera clausa and Mesocestoides sp.).
Lacerta viridis is a new host record for the first five of these species.
Communities of intestinal helminths of L. viridis consist of a few species which
resulted in a low species richness, abundance and diversity of infracommunities,
which exhibit substantial homogeneity among the four samples. A similar pattern
of dominance of two nematode species leading to a relatively high community
similarity at both infra- and component community levels was observed. While
intestinal helminth communities in lizards from 'marginal' habitats were
dominated by the host generalist, O. filiformis, those in hosts from 'typical'
habitats were dominated by the lizard specialist S. extenuatus. The results
indicate that the characteristics of the host's habitat are important in
determining the composition rather than structure of intestinal helminth
communities in L. viridis.
PMID- 9765379
TI - The ultrastructure of the cuticle and sheath of infective juveniles of
entomopathogenic steinernematid nematodes.
AB - The ultrastructure of the cuticle of infective juveniles (IJs) of Steinernema
carpocapsae (newly emerged and 80-day-old) and newly emerged IJs of S. riobravis,
S. feltiae and S. glaseri was examined using transmission electron microscopy.
The thickness of four distinctive layers of the cuticle was measured: epicuticle,
cortical and median layer, striated layer and fibrous mat. The thickness of the
cuticle was correlated with the size of the IJ. In the case of newly emerged IJs,
the smallest species, S. carpocapsae, had a cuticle thickness of c. 270 nm
compared with c. 460 nm for S. glaseri, the largest of the four species. The
overall thickness of the cuticle or the thickness of the cuticle layers was not
correlated with the ability of the IJs of the four species to survive desiccation
per se. The major difference between newly emerged IJs of the four species was
that S. carpocapsae had a proportionately thicker striated layer compared with
the other three species. The significance of this is not known but it may be an
adaptation involving the nictation behaviour of this species. A substantial
change was observed in the cuticle of aged (80-day-old) IJs of S. carpocapsae,
whereby the thickness of the cortical and median layer increased by more than
100% and the overall thickness of the cuticle increased by about 50%. Two
possible explanations for this increase are: (i) new material was synthesized; or
(ii) the fluid content of this layer increased due to an increase in the
permeability of the outer layers of the cuticle. The ultrastructure of the
sheaths of S. feltiae and S. glaseri was also examined and, apart from S. glaseri
having a thicker sheath, the structure of the sheath in both species was similar,
with the epicuticle and striated layer still visible.
PMID- 9765381
TI - Eosinophil chemotactic factors from cysticercoids of Hymenolepis nana.
AB - A comparative study of eosinophil chemotactic factors was carried out using
cysticercoids and oncospheres of Hymenolepis nana. Cysticercoids showed twice the
chemotactic activity for eosinophils than the oncospheres. Eosinophilia induced
by oncospheres and cysticercoids observed in secondary and primary infections,
respectively, were discussed from the view point of the immunobiology of this
parasite.
PMID- 9765382
TI - A third-generation lentivirus vector with a conditional packaging system.
AB - Vectors derived from human immunodeficiency virus (HIV) are highly efficient
vehicles for in vivo gene delivery. However, their biosafety is of major concern.
Here we exploit the complexity of the HIV genome to provide lentivirus vectors
with novel biosafety features. In addition to the structural genes, HIV contains
two regulatory genes, tat and rev, that are essential for HIV replication, and
four accessory genes that encode critical virulence factors. We previously
reported that the HIV type 1 accessory open reading frames are dispensable for
efficient gene transduction by a lentivirus vector. We now demonstrate that the
requirement for the tat gene can be offset by placing constitutive promoters
upstream of the vector transcript. Vectors generated from constructs containing
such a chimeric long terminal repeat (LTR) transduced neurons in vivo at very
high efficiency, whether or not they were produced in the presence of Tat. When
the rev gene was also deleted from the packaging construct, expression of gag and
pol was strictly dependent on Rev complementation in trans. By the combined use
of a separate nonoverlapping Rev expression plasmid and a 5' LTR chimeric
transfer construct, we achieved optimal yields of vector of high transducing
efficiency (up to 10(7) transducing units [TU]/ml and 10(4) TU/ng of p24). This
third-generation lentivirus vector uses only a fractional set of HIV genes: gag,
pol, and rev. Moreover, the HIV-derived constructs, and any recombinant between
them, are contingent on upstream elements and trans complementation for
expression and thus are nonfunctional outside of the vector producer cells. This
split-genome, conditional packaging system is based on existing viral sequences
and acts as a built-in device against the generation of productive recombinants.
While the actual biosafety of the vector will ultimately be proven in vivo, the
improved design presented here should facilitate testing of lentivirus vectors.
PMID- 9765383
TI - Canine distemper virus DNA vaccination induces humoral and cellular immunity and
protects against a lethal intracerebral challenge.
AB - We have studied the immune responses to the two glycoproteins of the
Morbillivirus canine distemper virus (CDV) after DNA vaccination of BALB/c mice.
The plasmids coding for both CDV hemagglutinin (H) and fusion protein (F) induce
high levels of antibodies which persist for more than 6 months. Intramuscular
inoculation of the CDV DNA induces a predominantly immunoglobulin G2a (IgG2a)
response (Th1 response), whereas gene gun immunization with CDV H evokes
exclusively an IgG1 response (Th2 response). In contrast, the CDV F gene elicited
a mixed, IgG1 and IgG2a response. Mice vaccinated (by gene gun) with either the
CDV H or F DNA showed a class I-restricted cytotoxic lymphocyte response.
Immunized mice challenged intracerebrally with a lethal dose of a neurovirulent
strain of CDV were protected. However, approximately 30% of the mice vaccinated
with the CDV F DNA became obese in the first 2 months following the challenge.
This was not correlated with the serum antibody levels.
PMID- 9765384
TI - High-mobility group 1/2 proteins are essential for initiating rolling-circle-type
DNA replication at a parvovirus hairpin origin.
AB - Rolling-circle replication is initiated by a replicon-encoded endonuclease which
introduces a single-strand nick into specific origin sequences, becoming
covalently attached to the 5' end of the DNA at the nick and providing a 3'
hydroxyl to prime unidirectional, leading-strand synthesis. Parvoviruses, such as
minute virus of mice (MVM), have adapted this mechanism to amplify their linear
single-stranded genomes by using hairpin telomeres which sequentially unfold and
refold to shuttle the replication fork back and forth along the genome, creating
a continuous, multimeric DNA strand. The viral initiator protein, NS1, then
excises individual genomes from this continuum by nicking and reinitiating
synthesis at specific origins present within the hairpin sequences. Using in
vitro assays to study ATP-dependent initiation within the right-hand (5') MVM
hairpin, we have characterized a HeLa cell factor which is absolutely required to
allow NS1 to nick this origin. Unlike parvovirus initiation factor (PIF), the
cellular complex which activates NS1 endonuclease activity at the left-hand (3')
viral origin, the host factor which activates the right-hand hairpin elutes from
phosphocellulose in high salt, has a molecular mass of around 25 kDa, and appears
to bind preferentially to structured DNA, suggesting that it might be a member of
the high-mobility group 1/2 (HMG1/2) protein family. This prediction was
confirmed by showing that purified calf thymus HMG1 and recombinant human HMG1 or
murine HMG2 could each substitute for the HeLa factor, activating the NS1
endonuclease in an origin-specific nicking reaction.
PMID- 9765385
TI - The Epstein-Barr virus (EBV) SM protein enhances pre-mRNA processing of the EBV
DNA polymerase transcript.
AB - The Epstein-Barr virus (EBV) DNA polymerase (pol) mRNA, which contains a
noncanonical polyadenylation signal, UAUAAA, is cleaved and polyadenylated
inefficiently (S. C. S. Key and J. S. Pagano, Virology 234:147-159, 1997). We
postulated that the EBV early proteins SM and M, which appear to act
posttranscriptionally and are homologs of herpes simplex virus (HSV) ICP27, might
compensate for the inefficient processing of pol pre-mRNA. Here we show that the
SM and M proteins interact with each other in vitro. In addition, glutathione S
transferase-SM/M fusion proteins precipitate the heterogeneous ribonucleoprotein
(hnRNP) C1 splicing protein. Further, the SM protein is coimmunoprecipitated from
SM-expressing cell extracts with an antibody to the hnRNP A1/A2 proteins, which
are splicing and nuclear shuttling proteins. Finally, the amount of processed EBV
DNA polymerase mRNA was increased three- to fourfold in a HeLa cell line
expressing SM; this increase was not due to enhanced transcription. Thus,
inefficient processing of EBV pol RNA by cellular cleavage and polyadenylation
factors appears to be compensated for and may be regulated by the early EBV
protein, SM, perhaps via RNA 3'-end formation.
PMID- 9765386
TI - Molecular evidence for mother-to-child transmission of multiple variants by
analysis of RNA and DNA sequences of human immunodeficiency virus type 1.
AB - We have examined the viral selection that may occur during transmission by
studying the env gene sequences from four cases of mother-to-child transmission
of human immunodeficiency virus type 1. The V3 region sequences were directly
amplified from both plasma viral RNA and peripheral blood mononuclear cells
containing proviral DNA from mothers at delivery and at the time of diagnosis for
children. Transmission occurred perinatally in three cases. The similarity of the
viral sequences in each infant sample contrasted with the heterogeneous viral
populations in the mothers. Phylogenetic analysis indicated the transmission of
one or a few closely related maternal minor virus variants. In contrast, the
child virus population in the fourth case was as heterogeneous as that of his
mother, and phylogenetic analysis strongly suggested the transmission of multiple
maternal variants. This case of multiple transmission was confirmed by analyzing
sequences obtained at three times after delivery. Strains with sequences
corresponding to the syncytium-inducing phenotype were also transmitted in this
fourth case, and this was associated with the rapid development of disease in the
child. There was no evidence for transmission of particular viral variants from
mother to infant. We have thus described a particular case of vertical human
immunodeficiency virus type 1 transmission with the transmission of multiple
maternal variants to the infant and a rapid, fatal outcome in the child.
PMID- 9765387
TI - Enhancer requirement for murine cytomegalovirus growth and genetic
complementation by the human cytomegalovirus enhancer.
AB - The cytomegalovirus (CMV) enhancer is a highly complex regulatory region
containing multiple elements that interact with a variety of host-encoded
transcription factors. Many of these sequence elements are conserved among the
different species strains of CMV, although the arrangement of the various
elements and overall sequence composition of the CMV enhancers differ remarkably.
To delineate the importance of this region to a productive infection and to
explore the possibility of generating a murine CMV (MCMV) under the control of
human CMV (HCMV) genetic elements, the MCMV enhancer was resected and replaced
either with nonregulatory sequences or with paralogous sequences from HCMV. The
effects of these various deletions and substitutions on viral growth in
transfected or infected tissue-culture cells were evaluated. We found that
mutations in MCMV that eliminate or substitute for the enhancer with
nonregulatory sequences showed a severe deficiency in virus synthesis. This
growth defect is effectively complemented by the homologous MCMV enhancer as well
as the HCMV enhancer. In the latter case, the chimeric viruses (hybrid MCMV
strains) containing the molecularly shuffled human enhancer exhibit infectious
kinetics similar to that of parental wild-type and wild-type revertant MCMV.
These results also show that open reading frames m124, m124.1, and m125 located
within the enhancer region are nonessential for growth of MCMV in cells. Most
importantly, we conclude that the enhancer of MCMV is required for optimal
infection and that its diverged human counterpart can advantageously replace its
role in promoting viral infectivity.
PMID- 9765389
TI - Coronavirus transcription early in infection.
AB - We studied the accumulation kinetics of murine coronavirus mouse hepatitis virus
(MHV) RNAs early in infection by using cloned MHV defective interfering (DI) RNA
that contained an intergenic sequence from which subgenomic DI RNA is synthesized
in MHV-infected cells. Genomic DI RNA and subgenomic DI RNA accumulated at a
constant ratio from 3 to 11 h postinfection (p.i.) in the cells infected with MHV
containing DI particles. Earlier, at 1 h p.i., this ratio was not constant; only
genomic DI RNA accumulated, indicating that MHV RNA replication, but not MHV RNA
transcription, was active during the first hour of MHV infection. Negative-strand
genomic DI RNA and negative-strand subgenomic DI RNA were first detectable at 1
and 3 h p.i., respectively, and the amounts of both RNAs increased gradually
until 6 h p.i. These data showed that at 2 h p.i., subgenomic DI RNA was
undergoing synthesis in the cells in which negative-strand subgenomic DI RNA was
undetectable. These data, therefore, signify that negative-strand genomic DI RNA,
but not negative-strand subgenomic DI RNA, was an active template for subgenomic
DI RNA synthesis early in infection.
PMID- 9765388
TI - Inactivation of p53 but not p73 by adenovirus type 5 E1B 55-kilodalton and E4 34
kilodalton oncoproteins.
AB - The adenovirus E1B 55-kDa and E4 34-kDa oncoproteins bind and inactivate the p53
tumor suppressor gene product, resulting in cell transformation. A recently
discovered cellular protein, p73, shows extensive similarities to p53 in
structure and function. Here we show that the simultaneous transient expression
of E1B 55-kDa and E4 34-kDa proteins is sufficient to drastically shorten the
intracellular half-life of p53, leading to strongly reduced steady-state p53
levels. Concomitantly, the E1B 55-kDa and E4 34-kDa proteins act synergistically
to inactivate the transcriptional activity of p53. Mutational analysis suggests
that physical interactions between the E1B 55-kDa protein and p53 and between the
E1B 55-kDa and E4 34-kDa proteins are both required for p53 degradation. In
contrast, the ability of p53 to interact with the cellular mdm2 oncoprotein or
with its cognate DNA element appears to be dispensable for its destabilization by
adenovirus gene products. The adenovirus E1B 55-kDa protein did not detectably
interact with p73 and failed to inhibit p73-mediated transcription; also, the E1B
55-kDa and E4 34-kDa proteins did not promote p73 degradation. When five amino
acids near the amino termini were exchanged at corresponding positions between
p53 and p73, this rendered p53 resistant and p73 susceptible to complex formation
and inactivation by the E1B 55-kDa protein. Our results suggest that while p53
inactivation is a central step in virus-induced tumor development, efficient
transformation can occur without targeting p73.
PMID- 9765390
TI - Herpes simplex virus 1 regulatory protein ICP22 interacts with a new cell cycle
regulated factor and accumulates in a cell cycle-dependent fashion in infected
cells.
AB - The herpes simplex virus 1 infected cell protein 22 (ICP22), the product of the
alpha22 gene, is a nucleotidylylated and phosphorylated nuclear protein with
properties of a transcriptional factor required for the expression of a subset of
viral genes. Here, we report the following. (i) ICP22 interacts with a previously
unknown cellular factor designated p78 in the yeast two-hybrid system. The p78
cDNA encodes a polypeptide with a distribution of leucines reminiscent of a
leucine zipper. (ii) In uninfected and infected cells, antibody to p78 reacts
with two major bands with an apparent Mr of 78,000 and two minor bands with
apparent Mrs of 62, 000 and 55,000. (ii) p78 also interacts with ICP22 in vitro.
(iii) In uninfected cells, p78 was dispersed largely in the nucleoplasm in HeLa
cells and in the nucleoplasm and cytoplasm in HEp-2 cells. After infection, p78
formed large dense bodies which did not colocalize with the viral regulatory
protein ICP0. (iv) Accumulation of p78 was cell cycle dependent, being highest
very early in S phase. (v) The accumulation of ICP22 in synchronized cells was
highest in early S phase, in contrast to the accumulation of another protein,
ICP27, which was relatively independent of the cell cycle. (vi) In the course of
the cell cycle, ICP22 was transiently modified in an aberrant fashion, and this
modification coincided with expression of p78. The results suggest that ICP22
interacts with and may be stabilized by cell cycle-dependent proteins.
PMID- 9765391
TI - Specific interaction of heterogeneous nuclear ribonucleoprotein particle U with
the leader RNA sequence of vesicular stomatitis virus.
AB - The 3' ends of the genome and antigenome RNA of vesicular stomatitis virus (VSV)
serve as the promoter sites for the RNA-dependent RNA polymerase in the
initiation of transcription and replication, respectively. The leader RNA, the
first transcript synthesized during the RNA synthetic step, contains sequences to
initiate encapsidation with the nucleocapsid protein, which is a prerequisite for
replication. It also plays a role in the inhibition of cellular RNA synthesis. To
search for a specific cellular factor(s) which may interact with the leader RNA
sequences and regulate these processes, we used a gel mobility shift assay to
identify such a protein(s). By using nuclear extract, it was found that in
addition to the previously reported La protein, a 120-kDa nuclear protein
specifically interacts with the leader RNA. Biochemical and immunological studies
identified the 120-kDa protein as heterogeneous nuclear ribonucleoprotein
particle U (hnRNP U), which is involved in pre-mRNA processing. We also
demonstrate that hnRNP U is associated with the leader RNA in the nuclei of VSV
infected cells and also packaged within the purified virions. By double
immunofluorescence labeling and confocal microscopy, hnRNP U appears to
colocalize with the virus in the cytoplasm of infected cells. These results
strongly suggest that hnRNP U plays an important role in the life cycle of VSV.
PMID- 9765392
TI - Structure of double-shelled rice dwarf virus.
AB - Rice dwarf virus (RDV), a member of the Reoviridae family, is a double-stranded
RNA virus. Infection of rice plants with RDV reduces crop production
significantly and can pose a major economic threat to Southeast Asia. A 25-A
three-dimensional structure of the 700-A-diameter RDV capsid has been determined
by 400-kV electron cryomicroscopy and computer reconstruction. The structure
revealed two distinctive icosahedral shells: a T=13l outer icosahedral shell
composed of 260 trimeric clusters of P8 (46 kDa) and an inner T=1 icosahedral
shell of 60 dimers of P3 (114 kDa). Sequence and structural comparisons were made
between the RDV outer shell trimer and the two crystal conformations (REF and
HEX) of the VP7 trimer of bluetongue virus, an animal analog of RDV. The low
resolution structural match of the RDV outer shell trimer to the HEX conformation
of VP7 trimer has led to the proposal that P8 consists of an upper domain of beta
sandwich motif and a lower domain of alpha helices. The less well fit REF
conformation of VP7 to the RDV trimer may be due to the differences between VP7
and P8 in the sequence of the hinge region that connects the two domains. The
additional mass density and the absence of a known signaling peptide on the
surface of the RDV outer shell trimer may be responsible for the different
interactions between plants and animal reoviruses.
PMID- 9765393
TI - The role of interferon in influenza virus tissue tropism.
AB - We have studied the pathogenesis of influenza virus infection in mice that are
unable to respond to type I or II interferons due to a targeted disruption of the
STAT1 gene. STAT1-/- animals are 100-fold more sensitive to lethal infection with
influenza A/WSN/33 virus than are their wild-type (WT) counterparts. Virus
replicated only in the lungs of WT animals following intranasal (i.n.) virus
inoculation, while STAT1-/- mice developed a fulminant systemic influenza virus
infection following either i.n. or intraperitoneal inoculation. We investigated
the mechanism underlying this altered virus tropism by comparing levels of virus
replication in fibroblast cell lines and murine embryonic fibroblasts derived
from WT mice, STAT-/- mice, and mice lacking gamma interferon (IFNgamma-/- mice)
or the IFN-alpha receptor (IFNalphaR-/- mice). Influenza A/WSN/33 virus
replicates to high titers in STAT1-/- or IFNalphaR-/- fibroblasts, while cells
derived from WT or IFNgamma-/- animals are resistant to influenza virus
infection. Immunofluorescence studies using WT fibroblast cell lines demonstrated
that only a small subpopulation of WT cells can be infected and that in the few
infected WT cells, virus replication is aborted at an early, nuclear phase. In
all organs examined except the lung, influenza A WSN/33 virus infection is
apparently prevented by an intact type I interferon response. Our results
demonstrate that type I interferon plays an important role in determining the
pathogenicity and tissue restriction of influenza A/WSN/33 virus in vivo and in
vitro.
PMID- 9765395
TI - Circular intermediates of recombinant adeno-associated virus have defined
structural characteristics responsible for long-term episomal persistence in
muscle tissue.
AB - Adeno-associated viral (AAV) vectors have demonstrated great utility for long
term gene expression in muscle tissue. However, the mechanisms by which
recombinant AAV (rAAV) genomes persist in muscle tissue remain unclear. Using a
recombinant shuttle vector, we have demonstrated that circularized rAAV
intermediates impart episomal persistence to rAAV genomes in muscle tissue. The
majority of circular intermediates had a consistent head-to-tail configuration
consisting of monomer genomes which slowly converted to large multimers of >12
kbp by 80 days postinfection. Importantly, long-term transgene expression was
associated with prolonged (80-day) episomal persistence of these circular
intermediates. Structural features of these circular intermediates responsible
for increased persistence included a DNA element encompassing two viral inverted
terminal repeats (ITRs) in a head-to-tail orientation, which confers a 10-fold
increase in the stability of DNA following incorporation into plasmid-based
vectors and transfection into HeLa cells. These studies suggest that certain
structural characteristics of AAV circular intermediates may explain long-term
episomal persistence with this vector. Such information may also aid in the
development of nonviral gene delivery systems with increased efficiency.
PMID- 9765394
TI - The Epstein-Barr virus lytic transactivator Zta interacts with the helicase
primase replication proteins.
AB - The Epstein-Barr virus transactivator Zta triggers lytic gene expression and is
essential for replication of the lytic origin, oriLyt. Previous analysis
indicated that the Zta activation domain contributed a replication-specific
function. We now show that the Zta activation domain interacts with components of
the EBV helicase-primase complex. The three helicase-primase proteins BBLF4
(helicase), BSLF1 (primase), and BBLF2/3 (primase-associated factor) were
expressed fused to the Myc epitope. When expression plasmids for BBLF4 or BBLF2/3
plus BSLF1 (primase subcomplex) were separately transfected, the proteins
localized to the cytoplasm. Interaction between Zta and the components of the
helicase-primase complex was tested by examining the ability of Zta to alter the
intracellular localization of these proteins. Cotransfection of Zta with Myc
BBLF4 resulted in nuclear translocation of Myc-BBLF4; similarly, cotransfection
of Zta with the primase subcomplex led to nuclear translocation of the Myc-BSLF1
and Myc-BBLF2/3 proteins. This relocalization provides evidence for an
interaction between Zta and the helicase and Zta and the primase subcomplex. An
affinity assay using glutathione S-transferase-Zta fusion proteins demonstrated
that Myc-BBLF4 and Myc-BBLF2/3 plus BSLF1 bound to the Zta activation domain
(amino acids 1 to 133). In the nuclear relocalization assay, the amino-terminal
25 amino acids of Zta were required for efficient interaction with the primase
subcomplex but not for interaction with BBLF4. Evidence for interaction between
oriLyt bound Zta and the helicase-primase complex was obtained in a
superactivation assay using an oriLyt-chloramphenicol acetyltransferase (CAT)
reporter. Zta activated expression from a CAT reporter containing the complete
oriLyt region and regulated by the oriLyt BHLF1 promoter. Cotransfection of the
helicase-primase proteins, one of which was fused to a heterologous activation
domain, led to Zta-dependent superactivation of CAT expression. This assay also
provided evidence for an interaction between the single-stranded DNA binding
protein, BALF2, and the Zta-tethered helicase-primase complex. The helicase
primase interaction is consistent with a role for Zta in stabilizing the
formation of an origin-bound replication complex.
PMID- 9765396
TI - Intracellular localization of poliovirus plus- and minus-strand RNA visualized by
strand-specific fluorescent In situ hybridization.
AB - The time courses of poliovirus plus- and minus-strand RNA synthesis in infected
HEp-2 cells were monitored separately, using a quantitative RNase assay. In
parallel, viral RNA and proteins were located in situ by confocal microscopy
within cells fixed by a protocol determined to retain their native size and
shape. Plus- and minus-strand RNAs were visualized by fluorescent in situ
hybridization (FISH) with strand-specific riboprobes. The probes were labelled
with different fluorochromes to allow for the simultaneous detection of plus- and
minus-strand RNA. The FISH experiments showed minus-strand RNA to be present in
distinct, regularly sized, round structures throughout the viral replication
cycle. Plus-strand RNA was found in the same structures and also in smaller
clusters of vesicles. Association of viral RNA with membranes was demonstrated by
combining FISH with immunofluorescence (IF) detection of the viral 2B- and 2C
containing P2 proteins, which are known to be markers for virus-induced
membranes. At early times postinfection, the virus-induced membranous structures
were distributed through most of the cytoplasm, whereas around peak RNA
synthesis, both RNA-associated membranous structures migrated to the center of
the cell. During this process, the plus- and minus-strand-containing larger
structures stayed as recognizable entities, whereas the plus-strand-containing
granules coalesced into a juxtanuclear area of membranous vesicles. An
involvement of Golgi-derived membranes in the formation of virus-induced vesicles
and RNA synthesis early in infection was investigated by IF with 2C- and Golgi
specific antibodies.
PMID- 9765398
TI - Reovirus growth in cell culture does not require the full complement of viral
proteins: identification of a sigma1s-null mutant.
AB - The reovirus sigma1s protein is a 14-kDa nonstructural protein encoded by the S1
gene segment. The S1 gene has been linked to many properties of reovirus,
including virulence and induction of apoptosis. Although the function of sigma1s
is not known, the sigma1s open reading frame is conserved in all S1 gene
sequences determined to date. In this study, we identified and characterized a
variant of type 3 reovirus, T3C84-MA, which does not express sigma1s. To
facilitate these experiments, we generated two monoclonal antibodies (MAbs) that
bind different epitopes of the sigma1s protein. Using these MAbs in immunoblot
and immunofluorescence assays, we found that L929 (L) cells infected with T3C84
MA do not contain sigma1s. To determine whether sigma1s is required for reovirus
infection of cultured cells, we compared the growth of T3C84-MA and its parental
strain, T3C84, in L cells and Madin-Darby canine kidney (MDCK) cells. After 48 h
of growth, yields of T3C84-MA were equivalent to yields of T3C84 in L cells and
were fivefold lower than yields of T3C84 in MDCK cells. After 7 days of growth
following adsorption at a low multiplicity of infection, yields of T3C84-MA and
T3C84 did not differ significantly in either L cells or MDCK cells. To determine
whether sigma1s is required for apoptosis induced by reovirus infection, T3C84-MA
and T3C84 were tested for their capacity to induce apoptosis, using an acridine
orange staining assay. In these experiments, the percentages of apoptotic cells
following infection with T3C84-MA and T3C84 were equivalent. These findings
indicate that nonstructural protein sigma1s is not required for reovirus growth
in cell culture and does not influence the capacity of reovirus to induce
apoptosis. Therefore, reovirus replication does not require the full complement
of virally encoded proteins.
PMID- 9765397
TI - Protection against fatal Sindbis virus encephalitis by beclin, a novel Bcl-2
interacting protein.
AB - bcl-2, the prototypic cellular antiapoptotic gene, decreases Sindbis virus
replication and Sindbis virus-induced apoptosis in mouse brains, resulting in
protection against lethal encephalitis. To investigate potential mechanisms by
which Bcl-2 protects against central nervous system Sindbis virus infection, we
performed a yeast two-hybrid screen to identify Bcl-2-interacting gene products
in an adult mouse brain library. We identified a novel 60-kDa coiled-coil
protein, Beclin, which we confirmed interacts with Bcl-2 in mammalian cells,
using fluorescence resonance energy transfer microscopy. To examine the role of
Beclin in Sindbis virus pathogenesis, we constructed recombinant Sindbis virus
chimeras that express full-length human Beclin (SIN/beclin), Beclin lacking the
putative Bcl-2-binding domain (SIN/beclinDeltaBcl-2BD), or Beclin containing a
premature stop codon near the 5' terminus (SIN/beclinstop). The survival of mice
infected with SIN/beclin was significantly higher (71%) than the survival of mice
infected with SIN/beclinDeltaBcl-2BD (9%) or SIN/beclinstop (7%) (P < 0.001). The
brains of mice infected with SIN/beclin had fewer Sindbis virus RNA-positive
cells, fewer apoptotic cells, and lower viral titers than the brains of mice
infected with SIN/beclinDeltaBcl-2BD or SIN/beclinstop. These findings
demonstrate that Beclin is a novel Bcl-2-interacting cellular protein that may
play a role in antiviral host defense.
PMID- 9765399
TI - A protein critical for a Theiler's virus-induced immune system-mediated
demyelinating disease has a cell type-specific antiapoptotic effect and a key
role in virus persistence.
AB - TO subgroup strains of Theiler's murine encephalomyelitis virus (TMEV) induce a
persistent central nervous system infection and demyelinating disease in mice.
This disease serves as an experimental model of multiple sclerosis (MS) because
the two diseases have similar inflammatory white matter pathologies and because
the immune system appears to mediate demyelination in both processes. We
previously reported (H. H. Chen, W. P. Wong, L. Zhang, P. L. Ward, and R. P.
Roos, Nat. Med. 1:927-931, 1995) that TO subgroup strains use an alternative
initiation codon (in addition to the AUG used to synthesize the picornavirus
polyprotein from one long open reading frame) to translate L*, a novel protein
that is out of frame with the polyprotein and which plays a key role in the
demyelinating disease. We now demonstrate that L* has antiapoptotic activity in
macrophage cells and is critical for virus persistence. The antiapoptotic action
of L* as well as the differential translation of L* and virion capsid proteins
may foster virus persistence in macrophages and interfere with virus clearance.
The regulation of apoptotic activity in inflammatory cells may be important in
the pathogenesis of TMEV-induced demyelinating disease as well as MS.
PMID- 9765400
TI - Dissemination of lymphocytic choriomeningitis virus from the gastric mucosa
requires G protein-coupled signaling.
AB - The gastric mucosa is an important portal of entry for lymphocytic
choriomeningitis virus (LCMV) infections. Within hours after intragastric (i.g.)
inoculation, virus appears in the gastric epithelia, then in the mesenteric lymph
nodes and spleen, and then in the liver and brain. By 72 h i.g.-inoculated virus
is widely disseminated and equivalent to intravenous (i.v.) infection (S. K. Rai,
B. K. Micales, M. S. Wu, D. S. Cheung, T. D. Pugh, G. E. Lyons, and M. S.
Salvato. Am. J. Pathol. 151:633-639, 1997). Pretreatment of mice with a G protein
inhibitor, pertussis toxin (PTx), delays LCMV dissemination after i.g., but not
after i.v., inoculation. Delayed infection was confirmed by plaque assays, by
reverse transcription-PCR, and by in situ hybridization. The differential PTx
effect on i.v. and i.g. infections indicates that dissemination from the gastric
mucosa requires signals transduced through heterotrimeric G protein complexes.
PTx has no direct effect on LCMV replication, but it modulates integrin
expression in part by blocking chemokine signals. LCMV infection of macrophages
up-regulates CD11a, and PTx treatment counteracts this. PTx may prevent early
LCMV dissemination by inhibiting the G protein-coupled chemotactic response of
macrophages infected during the initial exposure, thus blocking systemic virus
spread.
PMID- 9765401
TI - The herpes simplex virus US11 protein effectively compensates for the
gamma1(34.5) gene if present before activation of protein kinase R by precluding
its phosphorylation and that of the alpha subunit of eukaryotic translation
initiation factor 2.
AB - In herpes simplex virus-infected cells, viral gamma134.5 protein blocks the
shutoff of protein synthesis by activated protein kinase R (PKR) by directing the
protein phosphatase 1alpha to dephosphorylate the alpha subunit of eukaryotic
translation initiation factor 2 (eIF-2alpha). The amino acid sequence of the
gamma134.5 protein which interacts with the phosphatase has high homology to a
domain of the eukaryotic protein GADD34. A class of compensatory mutants
characterized by a deletion which results in the juxtaposition of the alpha47
promoter next to US11, a gamma2 (late) gene in wild-type virus-infected cells,
has been described. In cells infected with these mutants, protein synthesis
continues even in the absence of the gamma134.5 gene. In these cells, PKR is
activated but eIF-2alpha is not phosphorylated, and the phosphatase is not
redirected to dephosphorylate eIF-2alpha. We report the following: (i) in cells
infected with these mutants, US11 protein was made early in infection; (ii) US11
protein bound PKR and was phosphorylated; (iii) in in vitro assays, US11 blocked
the phosphorylation of eIF-2alpha by PKR activated by poly(I-C); and (iv) US11
was more effective if present in the reaction mixture during the activation of
PKR than if added after PKR had been activated by poly(I-C). We conclude the
following: (i) in cells infected with the compensatory mutants, US11 made early
in infection binds to PKR and precludes the phosphorylation of eIF-2alpha,
whereas US11 driven by its natural promoter and expressed late in infection is
ineffective; and (ii) activation of PKR by double-stranded RNA is a common
impediment countered by most viruses by different mechanisms. The gamma134.5 gene
is not highly conserved among herpesviruses. A likely scenario is that
acquisition by a progenitor of herpes simplex virus of a portion of the cellular
GADD34 gene resulted in a more potent and reliable means of curbing the effects
of activated PKR. US11 was retained as a gamma2 gene because, like many viral
proteins, it has multiple functions.
PMID- 9765404
TI - Immediate-early transactivator Rta of Epstein-Barr virus (EBV) shows multiple
epitopes recognized by EBV-specific cytotoxic T lymphocytes.
AB - We analyzed the immediate-early transactivator Rta of Epstein-Barr virus (EBV)
for its role as a target for specific cytotoxic T lymphocytes (CTL). Panels of
overlapping peptides covering the entire amino acid sequence of Rta were
synthesized and used to induce and analyze specific CTL responses in EBV-positive
donors. Using peptide-pulsed target cells, we found nine different CTL epitopes
that are distributed over the entire protein sequence. One epitope restricted by
HLA-A24 could be mapped to the decameric sequence DYCNVLNKEF between amino acid
positions 28 and 37 of the Rta protein. A second epitope could be assigned to the
same region of Rta (residues 25 to 39) and was shown to be restricted by HLA-B18.
Another, minimal epitope could be mapped to the nonameric sequence ATIGTAMYK
between amino acid positions 134 and 142; this peptide was restricted by HLA-A11.
Another four epitopes were proven to be restricted by HLA-A2, -A3, -B61, and -Cw4
and were located between Rta residues 225 and 239, 145 and 159, 529 and 543, and
393 and 407, respectively. For two other epitopes, only the location within the
Rta protein is known so far (residues 121 to 135 and 441 to 455); their exact HLA
restriction patterns have not yet been identified. Using target cells infected
with recombinant vaccinia virus containing the gene for Rta, we showed that six
of eight Rta-specific CTL lines recognized the corresponding peptides also after
endogenous processing. These data suggest that Rta comprises an important target
for EBV-specific cellular cytotoxicity. Together with recent findings of other
immediate-early and early proteins also acting as CTL targets, they reveal the
role of proteins of the lytic cycle in the immune recognition of EBV-infected
cells.
PMID- 9765403
TI - Coronavirus pseudoparticles formed with recombinant M and E proteins induce alpha
interferon synthesis by leukocytes.
AB - Transmissible gastroenteritis virus (TGEV), an enteric coronavirus of swine, is a
potent inducer of alpha interferon (IFN-alpha) both in vivo and in vitro.
Incubation of peripheral blood mononuclear cells with noninfectious viral
material such as inactivated virions or fixed, infected cells leads to early and
strong IFN-alpha synthesis. Previous studies have shown that antibodies against
the virus membrane glycoprotein M blocked the IFN induction and that two viruses
with a mutated protein exhibited a decreased interferogenic activity, thus
arguing for a direct involvement of M protein in this phenomenon. In this study,
the IFN-alpha-inducing activity of recombinant M protein expressed in the absence
or presence of other TGEV structural proteins was examined. Fixed cells
coexpressing M together with at least the minor structural protein E were found
to induce IFN-alpha almost as efficiently as TGEV-infected cells. Pseudoparticles
resembling authentic virions were released in the culture medium of cells
coexpressing M and E proteins. The interferogenic activity of purified
pseudoparticles was shown to be comparable to that of TGEV virions, thus
establishing that neither ribonucleoprotein nor spikes are required for IFN
induction. The replacement of the externally exposed, N-terminal domain of M with
that of bovine coronavirus (BCV) led to the production of chimeric particles with
no major change in interferogenicity, although the structures of the TGEV and BCV
ectodomains markedly differ. Moreover, BCV pseudoparticles also exhibited
interferogenic activity. Together these observations suggest that the ability of
coronavirus particles to induce IFN-alpha is more likely to involve a specific,
multimeric structure than a definite sequence motif.
PMID- 9765402
TI - Inhibition of human immunodeficiency virus Rev and human T-cell leukemia virus
Rex function, but not Mason-Pfizer monkey virus constitutive transport element
activity, by a mutant human nucleoporin targeted to Crm1.
AB - The hypothesis that the cellular protein Crm1 mediates human immunodeficiency
virus type 1 (HIV-1) Rev-dependent nuclear export posits that Crm1 can directly
interact both with the Rev nuclear export signal (NES) and with cellular
nucleoporins. Here, we demonstrate that Crm1 is indeed able to interact with
active but not defective forms of the HIV-1 Rev NES and of NESs found in other
retroviral nuclear export factors. In addition, we demonstrate that Crm1 can bind
the Rev NES when Rev is assembled onto the Rev response element RNA target and
that Crm1, like Rev, is a nucleocytoplasmic shuttle protein. Crm1 also
specifically binds the Rev NES in vitro, although this latter interaction is
detectable only in the presence of added Ran . GTP. Overexpression of a
truncated, defective form of the nucleoporin Nup214/CAN, termed DeltaCAN, that
retains Crm1 binding ability resulted in the effective inhibition of HIV-1 Rev or
human T-cell leukemia virus Rex-dependent gene expression. In contrast, DeltaCAN
had no significant affect on Mason-Pfizer monkey virus constitutive transport
element (MPMV CTE)-dependent nuclear RNA export or on the expression of RNAs
dependent on the cellular mRNA export pathway. As a result, DeltaCAN specifically
blocked late, but not early, HIV-1 gene expression in HIV-1-infected cells. These
data strongly validate Crm1 as a cellular cofactor for HIV-1 Rev and demonstrate
that the MPMV CTE nuclear RNA export pathway uses a distinct, Crm1-independent
mechanism. In addition, these data identify a novel and highly potent inhibitor
of leucine-rich NES-dependent nuclear export.
PMID- 9765405
TI - Potential contributions of viral envelope and host genetic factors in a human
immunodeficiency virus type 1-infected long-term survivor.
AB - The lack of clinical progression in some individuals despite prolonged human
immunodeficiency virus type 1 (HIV-1) infection may result from infection with
less-pathogenic viral strains. To address this question, we examined the HIV-1
envelope protein from a donor with a low viral burden, stable CD4(+) T-lymphocyte
counts, and little evidence of CD8(+) T-cell expansion, activation, or immune
activity. To avoid potential changes in envelope function resulting from
selection in vitro, envelope clones were constructed by using viral RNA isolated
from uncultured peripheral blood mononuclear cells (PBMC). The data showed that
recombinant viruses containing envelope sequences derived from RNA isolated from
patient PBMC replicated poorly in primary CD4(+) T cells but demonstrated
efficient growth in macrophages. The unusual phenotype of these viruses could not
be explained solely by differential utilization of coreceptors since the chimeric
viruses, as well as an uncloned isolate obtained from the same visit date, can
utilize CCR5. In addition, the donor's own cells appeared resistant to infection
with chimeric viruses containing autologous envelope sequences. Genotype analysis
revealed that the donor was heterozygous for the previously described 32-bp
deletion in CCR5 which may be linked with prolonged survival in HIV-1-infected
individuals. These data suggest that the changes in envelope sequences confer
properties of viral attenuation, which together with the CCR5 +/Delta32 genotype
could account for the long-term survival of this patient.
PMID- 9765407
TI - Interactions of soluble recombinant integrin alphav beta5 with human
adenoviruses.
AB - alphav integrins have been identified as coreceptors for adenovirus (Ad)
internalization; however, direct interactions of these molecules with Ad have not
been demonstrated. We report here the expression of soluble integrin alphav
beta5, which retains the ability to recognize the Ad penton base as well as
vitronectin, an Arg Gly Asp (RGD)-containing extracellular matrix protein.
Soluble integrin alphav beta5 reacted with seven different Ad serotypes
(subgroups A to E) in solid-phase binding assays. The soluble integrin exhibited
different levels of binding to each Ad serotype; however, binding to multiple Ad
types required the presence of divalent metal cations and was inhibited by a
synthetic RGD peptide, indicating that RGD and cation-binding sequences regulate
Ad interactions with alphav beta5. Incubation of Ad particles with soluble alphav
beta5 integrin also inhibited subsequent Ad internalization into epithelial cells
as well as virus attachment to monocytic cells. These findings suggest that
soluble alphav integrins or antagonists of these coreceptors could be used to
limit infection by multiple Ad types. The generation of soluble alphav integrins
should also permit further detailed kinetic and structural analysis of Ad
interactions with its coreceptors.
PMID- 9765406
TI - Multimer formation is not essential for nuclear export of human T-cell leukemia
virus type 1 Rex trans-activator protein.
AB - The Rex trans-regulatory protein of human T-cell leukemia virus type 1 (HTLV-1)
is required for the nuclear export of incompletely spliced and unspliced viral
mRNAs and is therefore essential for virus replication. Rex is a nuclear
phosphoprotein that directly binds to its cis-acting Rex response element RNA
target sequence and constantly shuttles between the nucleus and cytoplasm.
Moreover, Rex induces nuclear accumulation of unspliced viral RNA. Three protein
domains which mediate nuclear import-RNA binding, nuclear export, and Rex
oligomerization have been mapped within the 189-amino-acid Rex polypeptide. Here
we identified a different region in the carboxy-terminal half of Rex which is
also required for biological activity. In inactive mutants with mutations that
map within this region, as well as in mutants that are deficient in Rex-specific
multimerization, Rex trans activation could be reconstituted by fusion to a
heterologous leucine zipper dimerization interface. The intracellular trafficking
capabilities of wild-type and mutant Rex proteins reveal that biologically
inactive and multimerization-deficient Rex mutants are still efficiently
translocated from the nucleus to the cytoplasm. This observation indicates that
multimerization is essential for Rex function but is not required for nuclear
export. Finally, we are able to provide an improved model of the HTLV-1 Rex
domain structure.
PMID- 9765408
TI - Synthetic DNA replication bubbles bound and unwound with twofold symmetry by a
simian virus 40 T-antigen double hexamer.
AB - Dimerization of simian virus 40 T-antigen hexamers (TAgH) into double hexamers
(TAgDH) on model DNA replication forks has been found to greatly stimulate T
antigen DNA helicase activity. To explore the interaction of TAgDH with DNA
during unwinding, we examined the binding of TAgDH to synthetic DNA replication
bubbles. Tests of replication bubble substrates containing different single
stranded DNA (ssDNA) lengths indicated that efficient formation of a TAgDH
requires >/=40 nucleotides (nt) of ssDNA. DNase I probing of a substrate
containing a 60-nt ssDNA bubble complexed with a TAgDH revealed that T antigen
bound the substrate with twofold symmetry. The strongest protection was observed
over the 5' junction on each strand, with 5 bp of duplex DNA and approximately 17
nt of adjacent ssDNA protected from nuclease cleavage. Stimulation of the T
antigen DNA helicase activity by an increase in ATP concentration caused the
protection to extend in the 5' direction into the duplex region, while resulting
in no significant changes to the 3' edge of strongest protection. Our data
indicate that each TAgH encircles one ssDNA strand, with a different strand bound
at each junction. The process of DNA unwinding results in each TAgH interacting
with a greater length of DNA than was initially bound, suggesting the generation
of a more highly processive helicase complex.
PMID- 9765409
TI - Human cytotoxic T-lymphocyte repertoire to influenza A viruses.
AB - The murine CD8(+) cytotoxic-T-lymphocyte (CTL) repertoire appears to be quite
limited in response to influenza A viruses. The CTL responses to influenza A
virus in humans were examined to determine if the CTL repertoire is also very
limited. Bulk cultures revealed that a number of virus proteins were recognized
in CTL assays. CTL lines were isolated from three donors for detailed study and
found to be specific for epitopes on numerous influenza A viral proteins. Eight
distinct CD8(+) CTL lines were isolated from donor 1. The proteins recognized by
these cell lines included the nucleoprotein (NP), matrix protein (M1),
nonstructural protein 1 (NS1), polymerases (PB1 and PB2), and hemagglutinin (HA).
Two CD4(+) cell lines, one specific for neuraminidase (NA) and the other specific
for M1, were also characterized. These CTL results were confirmed by precursor
frequency analysis of peptide-specific gamma interferon-producing cells detected
by ELISPOT. The epitopes recognized by 6 of these 10 cell lines have not been
previously described; 8 of the 10 cell lines were cross-reactive to subtype H1N1,
H2N2, and H3N2 viruses, 1 cell line was cross-reactive to subtypes H1N1 and H2N2,
and 1 cell line was subtype H1N1 specific. A broad CTL repertoire was detected in
the two other donors, and cell lines specific for the NP, NA, HA, M1, NS1, and M2
viral proteins were isolated. These findings indicate that the human memory CTL
response to influenza A virus is broadly directed to epitopes on a wide variety
of proteins, unlike the limited response observed following infection of mice.
PMID- 9765410
TI - Measles virus attenuation associated with transcriptional impediment and a few
amino acid changes in the polymerase and accessory proteins.
AB - Measles virus (MV) isolated in B95a cells, a marmoset B-cell line, retains full
pathogenicity for cynomolgus monkeys, while its derivative obtained by adaptation
to the growth in Vero cells, a monkey kidney cell line, loses the pathogenic
potential (F. Kobune, H. Sakata, and A. Sugiura, J. Virol. 64:700-705, 1990).
Here, we show with a pair of strains, a fresh isolate (9301B) in B95a cells and
its Vero cell-adapted form (9301V), that the in vivo attenuation parallels the
decrease of replication and syncytium-inducing capabilities in the original B95a
cells and that these in vitro phenotypes are attributable to impediment of
transcription, which is already obvious at the level of primary transcription
catalyzed by the virion-associated RNA polymerase. On the other hand, cell fusion
assays detected no functional difference between the glycoproteins of the two
viruses. Essentially the same transcriptional impediment with reduced syncytium
induction following Vero cell adaptation was found with two other pairs of
strains that had been similarly prepared. Nucleotide sequence comparison between
the 9301B and 9301V viruses revealed that a few (at most five) amino acid
changes, which sporadically took place in the polymerase (L and P proteins)
and/or accessory V and C proteins, were responsible for the in vitro and in vivo
attenuation through adaptation to growth in Vero cells.
PMID- 9765411
TI - Ribosomal S27a coding sequences upstream of ubiquitin coding sequences in the
genome of a pestivirus.
AB - Molecular characterization of cytopathogenic (cp) bovine viral diarrhea virus
(BVDV) strain CP Rit, a temperature-sensitive strain widely used for vaccination,
revealed that the viral genomic RNA is about 15.2 kb long, which is about 2.9 kb
longer than the one of noncytopathogenic (noncp) BVDV strains. Molecular cloning
and nucleotide sequencing of parts of the genome resulted in the identification
of a duplication of the genomic region encoding nonstructural proteins NS3, NS4A,
and part of NS4B. In addition, a nonviral sequence was found directly upstream of
the second copy of the NS3 gene. The 3' part of this inserted sequence encodes an
N-terminally truncated ubiquitin monomer. This is remarkable since all described
cp BVDV strains with ubiquitin coding sequences contain at least one complete
ubiquitin monomer. The 5' region of the nonviral sequence did not show any
homology to cellular sequences identified thus far in cp BVDV strains. Databank
searches revealed that this second cellular insertion encodes part of ribosomal
protein S27a. Further analyses included molecular cloning and nucleotide
sequencing of the cellular recombination partner. Sequence comparisons strongly
suggest that the S27a and the ubiquitin coding sequences found in the genome of
CP Rit were both derived from a bovine mRNA encoding a hybrid protein with the
structure NH2-ubiquitin-S27a-COOH. Polyprotein processing in the genomic region
encoding the N-terminal part of NS4B, the two cellular insertions, and NS3 was
studied by a transient-expression assay. The respective analyses showed that the
S27a-derived polypeptide, together with the truncated ubiquitin, served as
processing signal to yield NS3, whereas the truncated ubiquitin alone was not
capable of mediating the cleavage. Since the expression of NS3 is strictly
correlated with the cp phenotype of BVDV, the altered genome organization leading
to expression of NS3 most probably represents the genetic basis of
cytopathogenicity of CP Rit.
PMID- 9765413
TI - Infection of ducklings with virus particles containing linear double-stranded
duck hepatitis B virus DNA: illegitimate replication and reversion.
AB - Double-stranded linear DNA is synthesized as a minor viral DNA species by all
hepadnaviruses. In a previous study (W. Yang and J. Summers, J. Virol. 69:4029
4036, 1995) we showed that virus particles containing linear DNA of the duck
hepatitis B virus (DHBV) could initiate an infection of primary duck hepatocytes.
In cells infected by linear DNA containing viruses the transcriptional template,
covalently closed circular DNA, was formed by circularization of linear DNA by
nonhomologous recombination between the two ends. This process was shown to
result in viral DNA replication through multiple generations of linear DNA
intermediates, a process we called illegitimate replication. In this study we
showed that viruses containing linear DHBV DNA produced by engineered insertions
in the r sequence, which encodes the 5' end of the pregenome, could infect
hepatocytes in vivo, and these hepatocytes proceeded to carry out illegitimate
replication. Nonhomologous recombination quickly produced revertants and partial
revertants in which all or part of the insertion was deleted. One such partial
revertant that replicated primarily through circular DNA intermediates, but which
synthesized elevated levels of linear DNA, could be sustained for several days as
the predominant genotype in vivo, but this mutant was eventually displaced by
variants showing full reversion to legitimate replication and that synthesized
normal low levels of linear DNA. Full revertants did not necessarily contain the
wild-type r sequence. The results suggest that the linear DNA produced during
DHBV infection initiates cycles of illegitimate replication by generating mutants
with altered r sequences. Some r sequence mutants carry out a mixture of
legitimate and illegitimate replication that can contribute to elevated
production of linear DNA in individual cells.
PMID- 9765412
TI - The molecular chaperone calnexin interacts with the NSP4 enterotoxin of rotavirus
in vivo and in vitro.
AB - Calnexin is an endoplasmic reticulum (ER)-associated molecular chaperone proposed
to promote folding and assembly of glycoproteins that traverse the secretory
pathway in eukaryotic cells. In this study we examined if calnexin interacts with
the ER-associated luminal (VP7) and transmembrane (NSP4) proteins of rotavirus.
Only glycosylated NSP4 interacted with calnexin and did so in a time-dependent
manner (half-life, 20 min). In vitro translation experiments programmed with gene
10 of rhesus rotavirus confirmed that calnexin recognizes only glycosylated NSP4.
Castanospermine (a glucosidase I and II inhibitor) experiments established that
calnexin associates only with partly deglucosylated (di- or monoglucosylated)
NSP4. Furthermore, enzymatic removal of the remaining glucose residues on the N
linked glycan units was essential to disengage the NSP4-calnexin complex. Novel
experiments with castanospermine revealed that glucose trimming and the calnexin
NSP4 interaction were not critical for the assembly of infectious virus.
PMID- 9765414
TI - Proteolytic processing and assembly of gag and gag-pol proteins of TED, a
baculovirus-associated retrotransposon of the gypsy family.
AB - TED (transposable element D) is an env-containing member of the gypsy family of
retrotransposons that represents a possible retrovirus of invertebrates. This
lepidopteran (moth) retroelement contains gag and pol genes that encode proteins
capable of forming viruslike particles (VLP) with reverse transcriptase. Since
VLP are likely intermediates in TED transposition, we investigated the roles of
gag and pol in TED capsid assembly and maturation. By using constructed
baculovirus vectors and TED Gag-specific antiserum, we show that the principal
translation product of gag (Pr55(gag)) is cleaved to produce a single VLP
structural protein, p37(gag). Replacement of Asp436 within the retrovirus-like
active site of the pol-encoded protease (PR) abolished Pr55(gag) cleavage and
demonstrated the requirement for PR in capsid processing. As shown by expression
of an in-frame fusion of TED gag and pol, PR is derived from the Gag-Pol
polyprotein Pr195(gag-pol). The PR cleavage site within Pr55(gag) was mapped to a
position near the junction of a basic, nucleocapsid-like domain and a C-terminal
acidic domain. Once released by cleavage, the C-terminal fragment was not
detected. This acidic fragment was dispensable for VLP assembly, as demonstrated
by the formation of VLP by C-terminal Pr55(gag) truncation proteins and
replacement of the acidic domain with a heterologous protein. In contrast, C
terminal deletions that extended into the adjacent nucleocapsid-like domain of
Pr55(gag) abolished VLP recovery and demonstrated that this central region
contributes to VLP assembly or stability, or both. Collectively, these data
suggest that the single TED protein p37(gag) provides both capsid and
nucleocapsid functions. TED may therefore use a simple processing strategy for
VLP assembly and genome packaging.
PMID- 9765415
TI - Definition and distribution analysis of glycoprotein B gene alleles of human
herpesvirus 7.
AB - As for other herpesviruses, glycoprotein B (gB) of human herpesvirus 7 (HHV-7) is
believed to play a major role in virus infection and as a target of the host
immunogenic response. Using nested PCR, we amplified the whole HHV-7 gB gene from
108 human peripheral blood mononuclear cell samples and studied its variability.
By means of restriction fragment length polymorphism (RFLP) analysis, three
distinct patterns, designated I, II, and III, were defined and detected at
frequencies of 93, 5, and 2%, respectively. Determination of the nucleotide
sequence allowed us to recognize five critical positions in the gB gene with six
specific combinations of point changes at these positions. These combinations
were gB alleles A, B, C, D, E, and F. Alleles D and E corresponded to RFLP
patterns II and III, respectively, while the other four alleles corresponded to
RFLP pattern I. Identical gB alleles were detected in serial samples as well as
in paired samples of blood and saliva from the same individuals, except for one
case. In contrast, the distribution of gB alleles differed according to the
geographical origin of the human samples: C was the most frequent allele in both
African and Caribbean samples, whereas F was the most frequent allele in European
ones. Although none of the allele-specific nucleotide changes induced any
modification at the protein level, the definition of gB alleles provided
convenient viral markers for the study of both HHV-7 infections and human
population genetics.
PMID- 9765416
TI - Isolation of an Arabidopsis thaliana mutant in which the multiplication of both
cucumber mosaic virus and turnip crinkle virus is affected.
AB - During the systemic infection of plants by viruses, host factors play an
important role in supporting virus multiplication. To identify and characterize
the host factors involved in this process, we isolated an Arabidopsis thaliana
mutant named RB663, in which accumulation of the coat protein (CP) of cucumber
mosaic virus (CMV) in upper uninoculated leaves was delayed. Genetic analyses
suggested that the phenotype of delayed accumulation of CMV CP in RB663 plants
was controlled by a monogenic, recessive mutation designated cum2-1, which is
located on chromosome III and is distinct from the previously characterized cum1
mutation. Multiplication of CMV was delayed in inoculated leaves of RB663 plants,
whereas the multiplication in RB663 protoplasts was similar to that in wild-type
protoplasts. This suggests that the cum2-1 mutation affects the cell-to-cell
movement of CMV rather than CMV replication within a single cell. In RB663
plants, the multiplication of turnip crinkle virus (TCV) was also delayed but
that of tobacco mosaic virus was not affected. As observed with CMV, the
multiplication of TCV was normal in protoplasts and delayed in inoculated leaves
of RB663 plants compared to that in wild-type plants. Furthermore, the phenotype
of delayed TCV multiplication cosegregated with the cum2-1 mutation as far as we
examined. Therefore, the cum2-1 mutation is likely to affect the cell-to-cell
movement of both CMV and TCV, implying a common aspect to the mechanisms of cell
to-cell movement in these two distinct viruses.
PMID- 9765417
TI - Specific encapsidation of nodavirus RNAs is mediated through the C terminus of
capsid precursor protein alpha.
AB - Flock house virus (FHV) is a small icosahedral insect virus with a bipartite,
messenger-sense RNA genome. Its T=3 icosahedral capsid is initially assembled
from 180 subunits of a single type of coat protein, capsid precursor protein
alpha (407 amino acids). Following assembly, the precursor particles undergo a
maturation step in which the alpha subunits autocatalytically cleave between
Asn363 and Ala364. This cleavage generates mature coat proteins beta (363
residues) and gamma (44 residues) and is required for acquisition of virion
infectivity. The X-ray structure of mature FHV shows that gamma peptides located
at the fivefold axes of the virion form a pentameric helical bundle, and it has
been suggested that this bundle plays a role in release of viral RNA during FHV
uncoating. To provide experimental support for this hypothesis, we generated
mutant coat proteins that carried deletions in the gamma region of precursor
protein alpha. Surprisingly, we found that these mutations interfered with
specific recognition and packaging of viral RNA during assembly. The resulting
particles contained large amounts of cellular RNAs and varying amounts of the
viral RNAs. Single-site amino acid substitution mutants showed that three
phenylalanines located at positions 402, 405, and 407 of coat precursor protein
alpha were critically important for specific recognition of the FHV genome. Thus,
in addition to its hypothesized role in uncoating and RNA delivery, the C
terminal region of coat protein alpha plays a significant role in recognition of
FHV RNA during assembly. A possible link between these two functions is
discussed.
PMID- 9765418
TI - Effects of mutations in the rubella virus E1 glycoprotein on E1-E2 interaction
and membrane fusion activity.
AB - Rubella virus (RV) virions contain two glycosylated membrane proteins, E1 and E2,
that exist as a heterodimer and form the viral spike complexes on the virion
surface. Formation of an E1-E2 heterodimer is required for transport of E1 out of
the endoplasmic reticulum lumen to the Golgi apparatus and plasma membrane. To
investigate the nature of the E1-E2 interaction, we have introduced mutations in
the internal hydrophobic region (residues 81 to 109) of E1. Substitution of
serine at Cys82 (mutant C82S) or deletion of this hydrophobic domain (mutant dt)
of E1 resulted in a disruption of the E1 conformation that ultimately affected E1
E2 heterodimer formation and cell surface expression of both E1 and E2.
Substitution of either aspartic acid at Gly93 (G93D) or glycine at Pro104 (P104G)
was found to impair neither E1-E2 heterodimer formation nor the transport of E1
and E2 to the cell surface. Fusion of RV-infected cells is induced by a brief
treatment at a pH below 6. 0. To test whether this internal hydrophobic domain is
involved in the membrane fusion activity of RV, transformed BHK cell lines
expressing either wild-type or mutant spike proteins were exposed to an acidic pH
and polykaryon formation was measured. No fusion activity was observed in the
C82S, dt, and G93D mutants; however, the wild type and the P104G mutant exhibited
fusogenic activities, with greater than 60% and 20 to 40% of the cells being
fused, respectively, at pH 4.8. These results suggest that it is likely that the
region of E1 between amino acids 81 and 109 is involved in the membrane fusion
activity of RV and that it may be important for the interaction of that protein
with E2 to form the E1-E2 heterodimer.
PMID- 9765419
TI - Three of the four nucleocapsid proteins of Marburg virus, NP, VP35, and L, are
sufficient to mediate replication and transcription of Marburg virus-specific
monocistronic minigenomes.
AB - This paper describes the first reconstituted replication system established for a
member of the Filoviridae, Marburg virus (MBGV). MBGV minigenomes containing the
leader and trailer regions of the MBGV genome and the chloramphenicol
acetyltransferase (CAT) gene were constructed. In MBGV-infected cells, these
minigenomes were replicated and encapsidated and could be passaged. Unlike most
other members of the order Mononegavirales, filoviruses possess four proteins
presumed to be components of the nucleocapsid (NP, VP35, VP30, and L). To
determine the protein requirements for replication and transcription, a reverse
genetic system was established for MBGV based on the vaccinia virus T7 expression
system. Northern blot analysis of viral RNA revealed that three nucleocapsid
proteins (NP, VP35, and L) were essential and sufficient for transcription as
well as replication and encapsidation. These data indicate that VP35, rather than
VP30, is the functional homologue of rhabdo- and paramyxovirus P proteins. The
reconstituted replication system was profoundly affected by the NP-to-VP35
expression ratio. To investigate whether CAT gene expression was achieved
entirely by mRNA or in part by full-length plus-strand minigenomes, a copy-back
minireplicon containing the CAT gene but lacking MBGV-specific transcriptional
start sites was employed in the artificial replication system. This construct was
replicated without accompanying CAT activity. It was concluded that the CAT
activity reflected MBGV-specific transcription and not replication.
PMID- 9765420
TI - Walleye retroviruses associated with skin tumors and hyperplasias encode cyclin D
homologs.
AB - Walleye dermal sarcoma (WDS) and walleye epidermal hyperplasia (WEH) are skin
diseases of walleye fish that appear and regress on a seasonal basis. We report
here that the complex retroviruses etiologically associated with WDS (WDS virus
[WDSV]) and WEH (WEH viruses 1 and 2 [WEHV1 and WEHV2, respectively]) encode D
type cyclin homologs. The retroviral cyclins (rv-cyclins) are distantly related
to one another and to known cyclins and are not closely related to any walleye
cellular gene based on low-stringency Southern blotting. Since aberrant
expression of D-type cyclins occurs in many human tumors, we suggest that
expression of the rv-cyclins may contribute to the development of WDS or WEH. In
support of this hypothesis, we show that rv-cyclin transcripts are made in
developing WDS and WEH and that the rv-cyclin of WDSV induces cell cycle
progression in yeast (Saccharomyces cerevisiae). WEHV1, WEHV2, and WDSV are the
first examples of retroviruses that encode cyclin homologs. WEH and WDS and their
associated retroviruses represent a novel paradigm of retroviral tumor induction
and, importantly, tumor regression.
PMID- 9765422
TI - Heterogeneous nuclear ribonucleoprotein L interacts with the 3' border of the
internal ribosomal entry site of hepatitis C virus.
AB - Translation initiation of hepatitis C virus (HCV) RNA occurs by internal entry of
a ribosome into the 5' nontranslated region in a cap-independent manner. The HCV
RNA sequence from about nucleotide 40 up to the N terminus of the coding sequence
of the core protein is required for efficient internal initiation of translation,
though the precise border of the HCV internal ribosomal entry site (IRES) has yet
to be determined. Several cellular proteins have been proposed to direct HCV IRES
dependent translation by binding to the HCV IRES. Here we report on a novel
cellular protein that specifically interacts with the 3' border of the HCV IRES
in the core-coding sequence. This protein with an apparent molecular mass of 68
kDa turned out to be heterogeneous nuclear ribonucleoprotein L (hnRNP L). The
binding of hnRNP L to the HCV IRES correlates with the translational efficiencies
of corresponding mRNAs. This finding suggests that hnRNP L may play an important
role in the translation of HCV mRNA through the IRES element.
PMID- 9765421
TI - In vitro processing of herpes simplex virus type 1 DNA replication intermediates
by the viral alkaline nuclease, UL12.
AB - Herpes simplex virus type 1 (HSV-1) DNA replication intermediates exist in a
complex nonlinear structure that does not migrate into a pulsed-field gel.
Genetic evidence suggests that the product of the UL12 gene, termed alkaline
nuclease, plays a role in processing replication intermediates (R. Martinez, R.
T. Sarisky, P. C. Weber, and S. K. Weller, J. Virol. 70:2075-2085, 1996). In this
study we have tested the hypothesis that alkaline nuclease acts as a structure
specific resolvase. Cruciform structures generated with oligonucleotides were
treated with purified alkaline nuclease; however, instead of being resolved into
linear duplexes as would be expected of a resolvase activity, the artificial
cruciforms were degraded. DNA replication intermediates were isolated from the
well of a pulsed-field gel ("well DNA") and treated with purified HSV-1 alkaline
nuclease. Although alkaline nuclease can degrade virion DNA to completion,
digestion of well DNA results in a smaller-than-unit-length product that migrates
as a heterogeneous smear; this product is resistant to further digestion by
alkaline nuclease. The smaller-than-unit-length products are representative of
the entire HSV genome, indicating that alkaline nuclease is not inhibited at
specific sequences. To further probe the structure of replicating DNA, well DNA
was treated with various known nucleases; our results indicate that replicating
DNA apparently contains no accessible double-stranded ends but does contain nicks
and gaps. Our data suggest that UL12 functions at nicks and gaps in replicating
DNA to correctly repair or process the replicating genome into a form suitable
for encapsidation.
PMID- 9765423
TI - The 3'-untranslated region of hepatitis C virus RNA enhances translation from an
internal ribosomal entry site.
AB - Translation of most eukaryotic mRNAs and many viral RNAs is enhanced by their
poly(A) tails. Hepatitis C virus (HCV) contains a positive-stranded RNA genome
which does not have a poly(A) tail but has a stretch of 98 nucleotides (X region)
at the 3'-untranslated region (UTR), which assumes a highly conserved stem-loop
structure. This X region binds a polypyrimidine tract-binding protein (PTB),
which also binds to the internal ribosome entry site (IRES) in HCV 5'-UTR. These
RNA-protein interactions may regulate its translation. We generated a set of HCV
RNAs differing only in their 3'-UTRs and compared their translation efficiencies.
HCV RNA containing the X region was translated three- to fivefold more than the
corresponding RNAs without this region. Mutations that abolished PTB binding in
the X region reduced, but did not completely abolish, enhancement in translation.
The X region also enhanced translation from another unrelated IRES (from
encephalomyocarditis virus RNA), but did not affect the 5'-end-dependent
translation of globin mRNA in either monocistronic or bicistronic RNAs. It did
not appear to affect RNA stability. The free X region added in trans, however,
did not enhance translation, indicating that the translational enhancement by the
X region occurs only in cis. These results demonstrate that the highly conserved
3' end of HCV RNA provides a novel mechanism for enhancement of HCV translation
and may offer a target for antiviral agents.
PMID- 9765424
TI - CD4 promoter transactivation by human herpesvirus 6.
AB - The observation that human herpesvirus 6 (HHV-6) can induce CD4 gene
transcription and expression in CD4(-) cells was reported several years ago (P.
Lusso, A. De Maria, M. Malnati, F. Lori, S. E. DeRocco, M. Baseler, and R. C.
Gallo, Nature 349:533-535, 1991) and subsequently confirmed (P. Lusso, M. S.
Malnati, A. Garzino-Demo, R. W. Crowley, E. O. Long, and R. C. Gallo, Nature
362:458-462, 1993; G. Furlini, M. Vignoli, E. Ramazzotti, M. C. Re, G. Visani,
and M. LaPlaca, Blood 87:4737-4745, 1996). Our objective was to identify the
mechanisms underlying such phenomena. Using reporter gene constructs driven by
the CD4 promoter, we report that HHV-6 can efficiently transactivate such genetic
elements. Activation of the CD4 promoter occurs in the presence of the viral DNA
polymerase inhibitor phosphonoformic acid, which limits expression to the
immediate-early and early classes of viral genes. Using deletion mutants and
specific CD4 promoter mutants, we identified an ATF/CRE binding site located at
nucleotides -67 to -60 upstream of the CD4 gene transcription start site that is
important for HHV-6 transactivation. The ATF/CRE site is also essential for CD4
promoter activation by forskolin, an activator of adenylate cyclase. Using
electrophoretic mobility shift assays and specific antibodies, we showed that
CREB-1 binds specifically to the -79 to -52 region of the CD4 promoter. Last, we
have identified two open reading frames (ORFs) of HHV-6, U86 and U89 from the
immediate-early locus A, that can transactivate the CD4 promoter in HeLa cells.
However, transactivation of the CD4 promoter by ORFs U86 and U89 is independent
of the CRE element, suggesting that additional HHV-6 ORFs are likely to
contribute to CD4 gene activation. Taken together, our results will help to
understand the complex interactions occurring between HHV-6 and the CD4 promoter
and provide additional information regarding the class of transcription factors
involved in the control of CD4 gene expression.
PMID- 9765425
TI - Adenovirus endocytosis requires actin cytoskeleton reorganization mediated by Rho
family GTPases.
AB - Adenovirus (Ad) endocytosis via alphav integrins requires activation of the lipid
kinase phosphatidylinositol-3-OH kinase (PI3K). Previous studies have linked PI3K
activity to both the Ras and Rho signaling cascades, each of which has the
capacity to alter the host cell actin cytoskeleton. Ad interaction with cells
also stimulates reorganization of cortical actin filaments and the formation of
membrane ruffles (lamellipodia). We demonstrate here that members of the Rho
family of small GTP binding proteins, Rac and CDC42, act downstream of PI3K to
promote Ad endocytosis. Ad internalization was significantly reduced in cells
treated with Clostridium difficile toxin B and in cells expressing a dominant
negative Rac or CDC42 but not a H-Ras protein. Viral endocytosis was also
inhibited by cytochalasin D as well as by expression of effector domain mutants
of Rac or CDC42 that impair cytoskeletal function but not JNK/MAP kinase pathway
activation. Thus, Ad endocytosis requires assembly of the actin cytoskeleton, an
event initiated by activation of PI3K and, subsequently, Rac and CDC42.
PMID- 9765426
TI - Vaccinia virus protein synthesis has a low requirement for the intact translation
initiation factor eIF4F, the cap-binding complex, within infected cells.
AB - The role of the cap-binding complex, eIF4F, in the translation of vaccinia virus
mRNAs has been analyzed within infected cells. Plasmid DNAs, which express
dicistronic mRNAs containing a picornavirus internal ribosome entry site,
produced within vaccinia virus-infected cells both beta-glucuronidase and a cell
surface-targeted single-chain antibody (sFv). Cells expressing sFv were selected
from nonexpressing cells, enabling analysis of protein synthesis specifically
within the transfected cells. Coexpression of poliovirus 2A or foot-and-mouth
disease virus Lb proteases, which cleaved translation initiation factor eIF4G,
greatly inhibited cap-dependent protein (beta-glucuronidase) synthesis. Under
these conditions, internal ribosome entry site-directed expression of sFv
continued and cell selection was maintained. Furthermore, vaccinia virus protein
synthesis persisted in the selected cells containing cleaved eIF4G. Thus, late
vaccinia virus protein synthesis has a low requirement for the intact cap-binding
complex eIF4F. This may be attributed to the short unstructured 5' noncoding
regions of the vaccinia virus mRNAs, possibly aided by the presence of poly(A) at
both 5' and 3' termini.
PMID- 9765428
TI - Virion incorporation of human immunodeficiency virus type 1 Nef is mediated by a
bipartite membrane-targeting signal: analysis of its role in enhancement of viral
infectivity.
AB - The nef gene of primate immunodeficiency viruses is essential for high-titer
virus replication and AIDS pathogenesis in vivo. In tissue culture, Nef is not
required for human immunodeficiency virus (HIV) infection but enhances viral
infectivity. We and others have shown that Nef is incorporated into HIV-1
particles and cleaved by the viral proteinase. To determine the signal for Nef
incorporation and to analyze whether virion-associated Nef is responsible for
enhancement of infectivity, we generated a panel of nef mutants and analyzed them
for virion incorporation of Nef and for their relative infectivities. We report
that N-terminal truncations of Nef abolished its incorporation into HIV
particles. Incorporation was reconstituted by targeting the respective proteins
to the plasma membrane by using a heterologous signal. Mutational analysis
revealed that both myristoylation and an N-terminal cluster of basic amino acids
were required for virion incorporation and for plasma membrane targeting of Nef.
Grafting the N-terminal anchor domain of Nef onto the green fluorescent protein
led to membrane targeting and virion incorporation of the resulting fusion
protein. These results indicate that Nef incorporation into HIV-1 particles is
mediated by plasma membrane targeting via an N-terminal bipartite signal which is
reminiscent of a Src homology region 4. Virion incorporation of Nef correlated
with enhanced infectivity of the respective viruses in a single-round replication
assay. However, the phenotypes of HIV mutants with reduced Nef incorporation only
partly correlated with their ability to replicate in primary lymphocytes,
indicating that additional or different mechanisms may be involved in this
system.
PMID- 9765427
TI - Rhesus macaques infected with macrophage-tropic simian immunodeficiency virus
(SIVmacR71/17E) exhibit extensive focal segmental and global glomerulosclerosis.
AB - We previously showed that inoculation of rhesus macaques with molecularly cloned
lymphocytetropic simian immunodeficiency virus (SIVmac239) results in SIV
associated nephropathy (SIVAN) and that the glomerulosclerotic lesions were
associated with the selection of macrophagetropic (M-tropic) variants (V. H.
Gattone et al., AIDS Res. Hum. Retroviruses 14:1163-1180, 1998). In the present
study, seven rhesus macaques were inoculated with M-tropic SIVmacR71/17E, and the
renal pathology was examined at necropsy. All SIVmacR71/17E-infected macaques
developed AIDS, and most developed other systemic complications, including SIV
induced encephalitis and lentivirus interstitial pneumonia. There was no
correlation between the length of infection (42 to 97 days), circulating CD4(+) T
cell counts, and renal disease. Of the seven macaques inoculated with
SIVmacR71/17E, five developed significant mesangial hyperplasia and expansion of
matrix and four were clearly azotemic (serum urea nitrogen concentration of 40 to
112 mg/dl). These same five macaques developed focal segmental to global
glomerulosclerotic lesions. Increased numbers of glomerular CD68(+) cells
(monocytes/macrophages) were found in glomeruli but not the tubulointerstitium of
the macaques inoculated with SIVmacR71/17E. All macaques had glomerular deposits
of immunoglobulin G (IgG), IgM, and tubuloreticular inclusions, and six of seven
had IgA deposition. However, there was no correlation between the presence of
circulating anti-SIVmac antibodies, immunoglobulin deposition, and glomerular
disease. Tubulointerstitial infiltrates were mild, with little or no correlation
to azotemia, while microcystic tubules were evident in those with
glomerulosclerosis or azotemia. The four most severely affected macaques were
positive for diffuse glomerular immunostaining for viral core p27 antigen, and
there was intense staining in the glomeruli of the two macaques with the most
severe glomerulosclerosis. Viral sequences were isolated from glomerular and
tubulointerstitial fractions from macaques with severe glomerulosclerosis but
only from the tubulointerstitial compartment of those that did not develop
glomerulosclerosis. Interviral recombinant viruses generated with env sequences
isolated from glomeruli confirmed the M-tropic nature of the virus found in the
glomeruli. The correlation between the increased number of CD68(+) cells
(monocytes/macrophages) in the glomeruli, the localization of p27 antigen in the
glomeruli, and the glomerular pathology confirms and extends our previous
observations of an association between glomerular infection and infiltration by M
tropic virus and SIVAN.
PMID- 9765429
TI - Isolation and characterization of a neuropathogenic simian immunodeficiency virus
derived from a sooty mangabey.
AB - Transfusion of blood from a simian immunodeficiency virus (SIV)- and simian T
cell lymphotropic virus-infected sooty mangabey (designated FGb) to rhesus and
pig-tailed macaques resulted in the development of neurologic disease in addition
to AIDS. To investigate the role of SIV in neurologic disease, virus was isolated
from a lymph node of a pig-tailed macaque (designated PGm) and the cerebrospinal
fluid of a rhesus macaque (designated ROn2) and passaged to additional macaques.
SIV-related neuropathogenic effects were observed in 100% of the pig-tailed
macaques inoculated with either virus. Lesions in these animals included
extensive formation of SIV RNA-positive giant cells in the brain parenchyma and
meninges. Based upon morphology, the majority of infected cells in both lymphoid
and brain tissue appeared to be of macrophage lineage. The virus isolates
replicated very well in pig-tailed and rhesus macaque peripheral blood
mononuclear cells (PBMC) with rapid kinetics. Differential replicative abilities
were observed in both PBMC and macrophage populations, with viruses growing to
higher titers in pig-tailed macaque cells than in rhesus macaque cells. An
infectious molecular clone of virus derived from the isolate from macaque PGm
(PGm5.3) was generated and was shown to have in vitro replication characteristics
similar to those of the uncloned virus stock. While molecular analyses of this
virus revealed its similarity to SIV isolates from sooty mangabeys, significant
amino acid differences in Env and Nef were observed. This virus should provide an
excellent system for investigating the mechanism of lentivirus-induced neurologic
disease.
PMID- 9765430
TI - Human T-cell lymphotropic/leukemia virus type 1 Tax abrogates p53-induced cell
cycle arrest and apoptosis through its CREB/ATF functional domain.
AB - Human T-cell lymphotropic/leukemia virus type 1 (HTLV-1) transforms human T cells
in vitro, and Tax, a potent transactivator of viral and cellular genes, plays a
key role in cell immortalization. Tax activity is mediated by interaction with
cellular transcription factors including members of the CREB/ATF family, the NF
kappaB/c-Rel family, serum response factor, and the coactivators CREB binding
protein-p300. Although p53 is usually not mutated in HTLV-1-infected T cells, its
half-life is increased and its function is impaired. Here we report that
transient coexpression of p53 and Tax results in the suppression of p53
transcriptional activity. Expression of Tax abrogates p53-induced G1 arrest in
the Calu-6 cell line and prevents the apoptosis induced by overexpressing p53 in
the HeLa/Tat cell line. The Tax mutants M22 and G148V, which selectively activate
the CREB/ATF pathway, exert these same biological effects on p53 function. In
contrast, the NF-kappaB-active Tax mutant M47 has no effect on p53 activity in
any of these systems. Consistent with the negative effect of Tax on p53, no
activity on a p53-responsive promoter was observed upon transfection of HTLV-1
infected T-cell lines. The p53 protein is expressed at high levels in the
nucleus, and nuclear extracts of HTLV-1-infected T cells bind constitutively to a
DNA oligonucleotide containing the p53 response element, indicating that Tax does
not interfere with p53 binding to DNA. Tax is able to suppress the
transactivation function of p53 in three different cell lines, and this
suppression required Tax-mediated activation of the CREB/ATF, but not the NF
kappaB/c-Rel, pathway. Tax and the active Tax mutants were able to abrogate the
G1 arrest and apoptosis induced by p53, and this effect does not correlate with
an altered localization of nuclear p53 or with the disruption of p53-DNA
complexes. The suppression of p53 activity by Tax could be important in T-cell
immortalization induced by HTLV-1.
PMID- 9765431
TI - Effect of host modification and age on airway epithelial gene transfer mediated
by a murine leukemia virus-derived vector.
AB - To study retroviral gene transfer to airway epithelia, we used a transient
transfection technique to generate high titers (approximately 10(9) infectious
units/ml after concentration) of murine leukemia virus (MuLV)-derived vectors
pseudotyped with the vesicular stomatitis virus envelope glycoprotein (VSV-G).
Transformed (CFT1) and primary airway epithelial cells were efficiently
transduced by a VSV-G-pseudotyped lacZ vector (HIT-LZ) in vitro. CFT1 cells and
primary cystic fibrosis (CF) airway cell monolayers infected with a vector (HIT
LCFSN) containing human CF transmembrane conductance regulator (CFTR) in the
absence of selection expressed CFTR, as assessed by Western blot analysis, and
exhibited functional correction of CFTR-mediated Cl- secretion. In vitro studies
of persistence suggested that pseudotransduction was not a significant problem
with our vector preparations. In a sulfur dioxide (SO2) inhalational injury
model, bromodeoxyuridine (BrdU) incorporation rates were measured and found to
exceed 50% in SO2-injured murine tracheal epithelium. HIT-LZ vector (multiplicity
of infection of approximately 10) instilled into the SO2-injured tracheas of
anesthetized mice transduced 6.1% +/- 1.3% of superficial airway cells in
tracheas of weanling mice (3 to 4 weeks old; n = 10), compared to 1.4 +/- 0.9% in
mice 5 weeks of age (n = 4) and 0.2% in mice older than 6 weeks (n = 15). No
evidence for gene transfer following delivery of HIT-LZ to tracheas of either
weanling or older mice not injured with SO2 was detected. Because only a small
fraction of BrdU-labeled airway cells were transduced, we examined the stability
of the vector. No significant loss of vector infectivity over intervals (2 h)
paralleling those of in vivo protocols was detected in in vitro assays using CFT1
cells. In summary, high-titer vectors permitted complementation of defective CFTR
mediated Cl- transport in CF airway cells in vitro without selection and
demonstrated that the age of the animal appeared to be a major factor affecting
in vivo retroviral transduction efficiency.
PMID- 9765432
TI - High-titer human immunodeficiency virus type 1-based vector systems for gene
delivery into nondividing cells.
AB - Previously we designed novel pseudotyped high-titer replication defective human
immunodeficiency virus type 1 (HIV-1) vectors to deliver genes into nondividing
cells (J. Reiser, G. Harmison, S. Kluepfel-Stahl, R. O. Brady, S. Karlsson, and
M. Schubert, Proc. Natl. Acad. Sci. USA 93:15266-15271, 1996). Since then we have
made several improvements with respect to the safety, flexibility, and efficiency
of the vector system. A three-plasmid expression system is used to generate
pseudotyped HIV-1 particles by transient transfection of human embryonic kidney
293T cells with a defective packaging construct, a plasmid coding for a
heterologous envelope (Env) protein, and a vector construct harboring a reporter
gene such as neo, ShlacZ (encoding a phleomycin resistance/beta-galactosidase
fusion protein), HSA (encoding mouse heat-stable antigen), or EGFP (encoding
enhanced green fluorescent protein). The packaging constructs lack functional
Vif, Vpr, and Vpu proteins and/or a large portion of the Env coding region as
well as the 5' and 3' long terminal repeats, the Nef function, and the presumed
packaging signal. Using G418 selection, we routinely obtained vector particles
pseudotyped with the vesicular stomatitis virus G glycoprotein (VSV-G) with
titers of up to 8 x 10(7) CFU/microgram of p24, provided that a functional Tat
coding region was present in the vector. Vector constructs lacking a functional
Tat protein yielded titers of around 4 x 10(6) to 8 x 10(6) CFU/microgram of p24.
Packaging constructs with a mutation within the integrase (IN) core domain
profoundly affected colony formation and expression of the reporter genes,
indicating that a functional IN protein is required for efficient transduction.
We explored the abilities of other Env proteins to allow formation of pseudotyped
HIV-1 particles. The rabies virus and Mokola virus G proteins yielded high-titer
infectious pseudotypes, while the human foamy virus Env protein did not. Using
the improved vector system, we successfully transduced contact-inhibited primary
human skin fibroblasts and postmitotic rat cerebellar neurons and cardiac
myocytes, a process not affected by the lack of the accessory proteins.
PMID- 9765433
TI - A functional role for neutralizing antibodies in Borna disease: influence on
virus tropism outside the central nervous system.
AB - Borna disease virus (BDV) is a negative-strand RNA virus that infects the central
nervous systems (CNS) of warm-blooded animals and causes disturbances of movement
and behavior. The basis for neurotropism remains poorly understood; however, the
observation that the distribution of infectious virus in immunocompetent rats is
different from that in immunoincompetent rats indicates a role for the immune
system in BDV tropism: whereas in immunocompetent rats virus is restricted to the
central, peripheral, and autonomic nervous systems, immunoincompetent rats also
have virus in nonneural tissues. In an effort to examine the influence of the
humoral immune response on BDV pathogenesis, we examined the effects of passive
immunization with neutralizing antiserum in immunoincompetent rats. Serum
transfer into immunoincompetent rats did not prevent persistent CNS infection but
did result in restriction of virus to neural tissues. These results indicate that
neutralizing antibodies may play a role in preventing generalized infection with
BDV.
PMID- 9765435
TI - Factors influencing adeno-associated virus-mediated gene transfer to human cystic
fibrosis airway epithelial cells: comparison with adenovirus vectors.
AB - Adeno-associated virus (AAV) vectors appear promising for use in gene therapy in
cystic fibrosis (CF) patients, yet many features of AAV-mediated gene transfer to
airway epithelial cells are not well understood. We compared the transduction
efficiencies of AAV vectors and adenovirus (Ad) vectors in immortalized cell
lines from CF patients and in nasal epithelial primary cultures from normal
humans and CF patients. Similar dose-dependent relationships between the vector
multiplicities of infection and the efficiencies of lacZ gene transfer were
observed. However, levels of transduction for both Ad and recombinant AAV (rAAV)
were significantly lower in the airway epithelial cell than in the control cell
lines HeLa and HEK 293. Transduction efficiencies differed among cultured
epithelial cell types, with poorly differentiated cells transducing more
efficiently than well-differentiated cells. A time-dependent increase in gene
expression was observed after infection for both vectors. For Ad, but not for
AAV, this increase was dependent on prolonged incubation of cells with the
vector. Furthermore, for rAAV (but not for rAd), the delay in maximal
transduction could be abrogated by wild-type Ad helper infection. Thus, although
helper virus is not required for maximal transduction, it increases the kinetics
by which this is achieved. Expression of Ad E4 open reading frame 6 or addition
of either hydroxyurea or camptothecin resulted in increased AAV transduction, as
previously demonstrated for nonairway cells (albeit to lower final levels),
suggesting that second-strand synthesis may not be the sole cause of inefficient
transduction. Finally, the efficiency of AAV-mediated ex vivo gene transfer to
lung cells was similar to that previously described for Ad vectors in that
transduction was limited to regions of epithelial injury and preferentially
targeted basal-like cells. These studies address the primary factors influencing
rAAV infection of human airway cells and should impact successful gene delivery
in CF patients.
PMID- 9765436
TI - Generation of infectious pancreatic necrosis virus from cloned cDNA.
AB - We developed a reverse genetics system for infectious pancreatic necrosis virus
(IPNV), a prototype virus of the Birnaviridae family, with the use of plus
stranded RNA transcripts derived from cloned cDNA. Full-length cDNA clones of the
IPNV genome that contained the entire coding and noncoding regions of RNA
segments A and B were constructed. Segment A encodes a 106-kDa precursor protein
which is cleaved to yield mature VP2, nonstructural protease, and VP3 proteins,
whereas segment B encodes the RNA-dependent RNA polymerase VP1. Plus-sense RNA
transcripts of both segments were prepared by in vitro transcription of
linearized plasmids with T7 RNA polymerase. Transfection of chinook salmon embryo
(CHSE) cells with combined transcripts of segments A and B generated infectious
IPNV particles 10 days posttransfection. Furthermore, a transfectant virus
containing a genetically tagged sequence was generated to confirm the feasibility
of this system. The presence and specificity of the recovered virus were
ascertained by immunofluorescence staining of infected CHSE cells with rabbit
anti-IPNV serum and by nucleotide sequence analysis. In addition, 3'-terminal
sequence analysis of RNA from the recovered virus showed that extraneous
nucleotides synthesized at the 3' end during in vitro transcription were
precisely trimmed or excluded during replication, and hence these were not
incorporated into the genome. An attempt was made to determine if RNA-dependent
RNA polymerase of IPNV and infectious bursal disease virus (IBDV), another
birnavirus, can support virus rescue in heterologous combinations. Thus, CHSE
cells were transfected with transcripts derived from IPNV segment A and IBDV
segment B and Vero cells were transfected with transcripts derived from IBDV
segment A and IPNV segment B. In either case, no infectious IPNV or IBDV
particles were generated even after a third passage in cell culture, suggesting
that viral RNA-dependent RNA polymerase is species specific. However, the reverse
genetics system for IPNV that we developed will greatly facilitate studies of
viral replication and pathogenesis and the design of a new generation of live
attenuated vaccines.
PMID- 9765434
TI - Induction of programmed cell death by parvovirus H-1 in U937 cells: connection
with the tumor necrosis factor alpha signalling pathway.
AB - The human promonocytic cell line U937 undergoes apoptosis upon treatment with
tumor necrosis factor alpha (TNF-alpha). This cell line has previously been shown
to be very sensitive to the lytic effect of the autonomous parvovirus H-1.
Parvovirus infection leads to the activation of the CPP32 ICE-like cysteine
protease which cleaves the enzyme poly(ADP-ribose)polymerase and induces
morphologic changes that are characteristic of apoptosis in a way that is similar
to TNF-alpha treatment. This effect is also observed when the U937 cells are
infected with a recombinant H-1 virus which expresses the nonstructural (NS)
proteins but in which the capsid genes are replaced by a reporter gene,
indicating that the induction of apoptosis can be assigned to the cytotoxic
nonstructural proteins in this cell system. The c-Myc protein, which is
overexpressed in U937 cells, is rapidly downregulated during infection, in
keeping with a possible role of this product in mediating the apoptotic cell
death induced by H-1 virus infection. Interestingly, four clones (designated RU)
derived from the U937 cell line and selected for their resistance to H-1 virus
(J. A. Lopez-Guerrero et al., Blood 89:1642-1653, 1997) failed to decrease c-Myc
expression upon treatment with differentiation agents and also resisted the
induction of cell death after TNF-alpha treatment. Our data suggest that the RU
clones have developed defense strategies against apoptosis, either by their
failure to downregulate c-Myc and/or by activating antiapoptotic factors.
PMID- 9765437
TI - Role of glutamine 17 of the bovine papillomavirus E5 protein in platelet-derived
growth factor beta receptor activation and cell transformation.
AB - The bovine papillomavirus E5 protein is a small, homodimeric transmembrane
protein that forms a stable complex with the cellular platelet-derived growth
factor (PDGF) beta receptor through transmembrane and juxtamembrane interactions,
resulting in receptor activation and cell transformation. Glutamine 17 in the
transmembrane domain of the 44-amino-acid E5 protein is critical for complex
formation and receptor activation, and we previously proposed that glutamine 17
forms a hydrogen bond with threonine 513 of the PDGF beta receptor. We have
constructed and analyzed mutant E5 proteins containing all possible amino acids
at position 17 and examined the ability of these proteins to transform C127
fibroblasts, which express endogenous PDGF beta receptor. Although several
position 17 mutants were able to transform cells, mutants containing amino acids
with side groups that were unable to participate in hydrogen bonding interactions
did not form a stable complex with the PDGF beta receptor or transform cells, in
agreement with the proposed interaction between position 17 of the E5 protein and
threonine 513 of the receptor. The nature of the residue at position 17 also
affected the ability of the E5 proteins to dimerize. Overall, there was an
excellent correlation between the ability of the various E5 mutant proteins to
bind the PDGF beta receptor, lead to receptor tyrosine phosphorylation, and
transform cells. Similar results were obtained in Ba/F3 hematopoietic cells
expressing exogenous PDGF beta receptor. In addition, treatment of E5-transformed
cells with a specific inhibitor of the PDGF receptor tyrosine kinase reversed the
transformed phenotype. These results confirm the central importance of the PDGF
beta receptor in mediating E5 transformation and highlight the critical role of
the residue at position 17 of the E5 protein in the productive interaction with
the PDGF beta receptor. On the basis of molecular modeling analysis and the known
chemical properties of the amino acids, we suggest a structural basis for the
role of the residue at position 17 in E5 dimerization and in complex formation
between the E5 protein and the PDGF beta receptor.
PMID- 9765438
TI - The herpes simplex virus gE-gI complex facilitates cell-to-cell spread and binds
to components of cell junctions.
AB - The herpes simplex virus (HSV) glycoprotein complex gE-gI mediates the spread of
viruses between adjacent cells, and this property is especially evident for cells
that form extensive cell junctions, e.g., epithelial cells, fibroblasts, and
neurons. Mutants lacking gE or gI are not compromised in their ability to enter
cells as extracellular viruses. Therefore, gE-gI functions specifically in the
movement of virus across cell-cell contacts and, as such, provides a molecular
handle on this poorly understood process. We expressed gE-gI in human epithelial
cells by using replication-defective adenovirus (Ad) vectors. gE-gI accumulated
at lateral surfaces of the epithelial cells, colocalizing with the adherens
junction protein beta-catenin but was not found on either the apical or basal
plasma membranes and did not colocalize with ZO-1, a component of tight
junctions. In subconfluent monolayers, gE-gI was found at cell junctions but was
absent from those lateral surfaces not in contact with another cell, as was the
case for beta-catenin. Similar localization of gE-gI to cell junctions was
observed in HSV-infected epithelial cells. By contrast, HSV glycoprotein gD,
expressed using a recombinant Ad vectors, was found primarily along the apical
surfaces of cells, with little or no protein found on the basal or lateral
surfaces. Expression of gE-gI without other HSV polypeptides did not cause
redistribution of either ZO-1 or beta-catenin or alter tight-junction functions.
Together these results support a model in which gE-gI accumulates at sites of
cell-cell contact by interacting with junctional components. We hypothesize that
gE-gI mediates transfer of HSV across cell junctions by virtue of these
interactions with cell junction components.
PMID- 9765439
TI - Development of a neutralizing antibody response during acute primary human
immunodeficiency virus type 1 infection and the emergence of antigenic variants.
AB - We monitored the primary humoral response to human immunodeficiency virus type 1
infection and showed that, in addition to antibodies to p24 and gp41, antigens
which form the basis of most diagnostic assays, the response included a
significant antibody response directed to the gp120 region of the infecting viral
quasispecies. When tested in a recombinant virus neutralization assay, these
antibodies were capable of inhibiting viral growth. We found the primary viral
quasispecies to solely utilize the CCR-5 chemokine receptor; however, recombinant
viruses differed in their cytopathology and in their sensitivity to beta
chemokine inhibition of viral growth. Sequence analysis of the gp120 open reading
frames showed that amino acid changes in the C1 (D-->G at position 62) and C4 (V-
>A at position 430) regions accounted for the phenotypic differences. These data
demonstrate that early in infection, polymorphism exists in envelope glycoprotein
coreceptor interactions and imply that therapeutic strategies targeted at this
step in the viral life cycle may lead to rapid resistance.
PMID- 9765440
TI - Tat protein induces human immunodeficiency virus type 1 (HIV-1) coreceptors and
promotes infection with both macrophage-tropic and T-lymphotropic HIV-1 strains.
AB - Chemokine receptors CCR5 and CXCR4 are the primary fusion coreceptors utilized
for CD4-mediated entry by macrophage (M)- and T-cell line (T)-tropic human
immunodeficiency virus type 1 (HIV-1) strains, respectively. Here we demonstrate
that HIV-1 Tat protein, a potent viral transactivator shown to be released as a
soluble protein by infected cells, differentially induced CXCR4 and CCR5
expression in peripheral blood mononuclear cells. CCR3, a less frequently used
coreceptor for certain M-tropic strains, was also induced. CXCR4 was induced on
both lymphocytes and monocytes/macrophages, whereas CCR5 and CCR3 were induced on
monocytes/macrophages but not on lymphocytes. The pattern of chemokine receptor
induction by Tat was distinct from that by phytohemagglutinin. Moreover, Tat
induced CXCR4 and CCR5 expression was dose dependent. Monocytes/macrophages were
more susceptible to Tat-mediated induction of CXCR4 and CCR5 than lymphocytes,
and CCR5 was more readily induced than CXCR4. The concentrations of Tat effective
in inducing CXCR4 and CCR5 expression were within the picomolar range and close
to the range of extracellular Tat observed in sera from HIV-1-infected
individuals. The induction of CCR5 and CXCR4 expression correlated with Tat
enhanced infectivity of M- and T-tropic viruses, respectively. Taken together,
our results define a novel role for Tat in HIV-1 pathogenesis that promotes the
infectivity of both M- and T-tropic HIV-1 strains in primary human leukocytes,
notably in monocytes/macrophages.
PMID- 9765441
TI - In vivo footprinting of the enhancer sequences in the upstream long terminal
repeat of Moloney murine leukemia virus: differential binding of nuclear factors
in different cell types.
AB - The enhancer sequences in the Moloney murine leukemia virus (M-MuLV) long
terminal repeat (LTR) are of considerable interest since they are crucial for
virus replication and the ability of the virus to induce T lymphomas. While
extensive studies have identified numerous nuclear factors that can potentially
bind to M-MuLV enhancer DNA in vitro, it has not been made clear which of these
factors are bound in vivo. To address this problem, we carried out in vivo
footprinting of the M-MuLV enhancer in infected cells by in vivo treatment with
dimethyl sulfate (DMS) followed by visualization through ligation-mediated PCR
(LMPCR) and gel electrophoresis. In vivo DMS-LMPCR footprinting of the upstream
LTR revealed evidence for factor binding at several previously characterized
motifs. In particular, protection of guanines in the central LVb/Ets and Core
sites within the 75-bp repeats was detected in infected NIH 3T3 fibroblasts, Ti-6
lymphoid cells, and thymic tumor cells. In contrast, factor binding at the NF-1
sites was found in infected fibroblasts but not in T-lymphoid cells. These
results are consistent with the results of previous experiments indicating the
importance of the LVb/Ets and Core sequences for many retroviruses and the
biological importance especially of the NF-1 sites in fibroblasts and T-lymphoid
cells. No evidence for factor binding to the glucocorticoid responsive element
and LVa sites was found. Additional sites of protein binding included a region in
the GC-rich sequences downstream of the 75-bp repeats (only in fibroblasts), a
hypersensitive guanine on the minus strand in the LVc site (only in T-lymphoid
cells), and a region upstream of the 75-bp repeats. These experiments provide
concrete evidence for the differential in vivo binding of nuclear factors to the
M-MuLV enhancers in different cell types.
PMID- 9765442
TI - Cytotoxic T-lymphocyte precursor frequencies in BALB/c mice after acute
respiratory syncytial virus (RSV) infection or immunization with a formalin
inactivated RSV vaccine.
AB - A better understanding of the immune response to live and formalin-inactivated
respiratory syncytial virus (RSV) is important for developing nonlive vaccines.
In this study, major histocompatibility complex (MHC) class I- and II-restricted,
RSV-specific cytotoxic T-lymphocyte precursor (CTLp) frequencies were determined
in bronchoalveolar lavage (BAL) samples and spleen lymphocytes of BALB/c mice
intranasally infected with live RSV or intramuscularly inoculated with formalin
inactivated RSV (FI-RSV). After RSV infection, both class I- and class II
restricted CTLps were detected by day 4 or 5 postinfection (p.i.). Peak CTLp
frequencies were detected by day 7 p.i. The class II-restricted CTLp frequencies
in the BAL following RSV infection were less than class I-restricted CTLp
frequencies through day 14 p.i., during which class I-restricted CTLp frequencies
remained elevated, but then declined by 48 days p.i. The frequencies of class II
restricted CTLps in the BAL were 2- to 10-fold less than those of class I
restricted CTLps. For spleen cells, frequencies of both MHC class I- and II
restricted CTLps to live RSV were similar. In contrast, class II-restricted CTLps
predominated in FI-RSV-vaccinated mice. RSV challenge of vaccinated mice resulted
in an increase in the frequency of class I-restricted CTLps at day 3 p.i. but did
not enhance class II-restricted CTLp frequencies. These studies demonstrate
differences in the CTLp response to live RSV infection compared with FI-RSV
immunization and help define possible mechanisms of enhanced disease after FI-RSV
immunization. In addition, these studies provide a quantitative means to address
potential vaccine candidates by examining both MHC class I- and II-restricted
CTLp frequencies.
PMID- 9765444
TI - African swine fever virus is enveloped by a two-membraned collapsed cisterna
derived from the endoplasmic reticulum.
AB - During the cytoplasmic maturation of African swine fever virus (ASFV) within the
viral factories, the DNA-containing core becomes wrapped by two shells, an inner
lipid envelope and an outer icosahedral capsid. We have previously shown that the
inner envelope is derived from precursor membrane-like structures on which the
capsid layer is progressively assembled. In the present work, we analyzed the
origin of these viral membranes and the mechanism of envelopment of ASFV.
Electron microscopy studies on permeabilized infected cells revealed the presence
of two tightly apposed membranes within the precursor membranous structures as
well as polyhedral assembling particles. Both membranes could be detached after
digestion of intracellular virions with proteinase K. Importantly, membrane loop
structures were observed at the ends of open intermediates, which suggests that
the inner envelope is derived from a membrane cisterna. Ultraestructural and
immunocytochemical analyses showed a close association and even direct
continuities between the endoplasmic reticulum (ER) and assembling virus
particles at the bordering areas of the viral factories. Such interactions become
evident with an ASFV recombinant that inducibly expresses the major capsid
protein p72. In the absence of the inducer, viral morphogenesis was arrested at a
stage at which partially and fully collapsed ER cisternae enwrapped the core
material. Together, these results indicate that ASFV, like the poxviruses,
becomes engulfed by a two-membraned collapsed cisterna derived from the ER.
PMID- 9765443
TI - Molecular cloning and characterization of viruses isolated from chimpanzees with
pathogenic human immunodeficiency virus type 1 infections.
AB - We have previously described the development of AIDS in a chimpanzee (C499)
infected with human immunodeficiency virus type 1 (HIV-1) and the subsequent
pathogenic HIV-1 infection in another chimpanzee (C455) transfused with blood
from C499 (F. J. Novembre et al., J. Virol. 71:4086-4091, 1997). In the present
study, two virus isolates were derived from these animals: HIV-1JC from
peripheral blood mononuclear cells (PBMC) of C499, and HIV-1NC from plasma of
C455. These virus isolates were used to generate two infectious molecular clones,
termed HIV-1JC16 and HIV-1NC7 (JC16 and NC7, respectively). Comparative analyses
of the sequences of the two clones showed that they were highly interrelated but
distinct. Based on heteroduplex mobility assays, JC16 and NC7 appear to represent
dominant viruses in the uncloned stock population. Compared with amino acid
sequences of the parental viruses HIV-1SF2, HIV-1LAV-1b, and HIV-1NDK, JC16 and
NC7 showed a number of differences, including insertions, deletions, and point
mutations spread throughout the genome. However, insertion/deletion footprints in
several genes of both JC16 and NC7 suggested that recombination between SF2 and
LAV-1b could have occurred, possibly contributing to the generation of a
pathogenic virus. Comparative in vitro analyses of the molecular clones and the
uncloned stocks of HIV-1JC and HIV-1NC revealed that these viruses had strikingly
similar replicative abilities in mitogen-stimulated PBMC and in macrophages.
Compared to the SF2 and LAV-1b isolates of HIV-1, HIV-1JC and HIV-1NC isolates
were more similar to LAV-1b with respect to the ability to replicate in mitogen
stimulated PBMC and macrophages. These viruses should prove to be useful in
mapping determinants of pathogenesis.
PMID- 9765446
TI - Functional differences between BHRF1, the Epstein-Barr virus-encoded Bcl-2
homologue, and Bcl-2 in human epithelial cells.
AB - BHRF1, a component of the restricted early antigen complex of the Epstein-Barr
virus lytic cycle, encodes a 17-kDa protein with both sequence and functional
homology to the antiapoptotic Bcl-2 oncogene. Recent work has suggested that
BHRF1 behaves like Bcl-2 in protecting cells from apoptosis induced by a range of
stimuli. In this study, the effect of BHRF1 and Bcl-2 on the growth and
differentiation of the SCC12F human epithelial cell line was examined. The levels
of stable transfected BHRF1 expression achievable in SCC12F cells was
consistently lower than that obtained with Bcl-2. While both BHRF1 and Bcl-2
inhibited epithelial differentiation, the effect of Bcl-2 was more pronounced,
resulting in an almost complete blockade of differentiation in organotypic raft
cultures. However, BHRF1-expressing SCC12F cells proliferated at a much higher
rate than SCC12F cells expressing Bcl-2, and this effect was supported by cell
cycle analysis which demonstrated that BHRF1, but not Bcl-2, promotes rapid
transit through the cell cycle. These data highlight important differences
between BHRF1 and Bcl-2 and suggest that BHRF1 may function to promote the
survival and proliferation of lytically infected cells. The proliferative
properties of BHRF1 described in this study, together with the demonstration that
other oncogenic gamma herpesviruses encode Bcl-2 homologues, suggests that these
proteins may serve to increase the susceptibility of virus-infected cells to
oncogenic transformation, thereby contributing to the development of virus
associated tumors.
PMID- 9765445
TI - Analysis of pol gene heterogeneity, viral quasispecies, and drug resistance in
individuals infected with group O strains of human immunodeficiency virus type 1.
AB - Nucleotide sequences of the reverse transcriptase (RT) coding region have been
compared in four new human immunodeficiency virus type 1 (HIV-1) group O
isolates. Phylogenetic analysis of this pol region highlights a cluster of these
four HIV-1 group O sequences with seven other group O isolates (5% intracluster
nucleotide sequence diversity) similar to clusters classified as subtypes in HIV
1 group M (an average of 4.9% intrasubtype sequence diversity). Based on these
analyses, this group O cluster has been designated subtype A-O. A longitudinal
study of a heterosexual couple infected with group O (ESP1 and ESP2) allowed a
detailed analysis of RT sequences (amino acids 28 to 219). Directed evolution and
a slightly higher mutation frequency was observed in the RT sequences of patient
ESP2, treated with antiretroviral drugs, than that from the untreated patient
ESP1. Antiretroviral treatment also selected for specific substitutions, M184V
and T215Y in the RT coding region, conferring resistance to 3'-dideoxy-3'
thiacytidine and zidovudine, respectively. A Gly98 to Glu RT substitution
identified in the treated patient suggests a possible reversion of a
nonnucleoside RT inhibitor-resistant phenotype. Using RT clones from this
longitudinal study, both heteroduplex tracking assay and cloning-sequencing
techniques were employed for an extensive genetic analysis of pol gene
quasispecies. Amino acid substitutions (i.e., Phe-77 to Leu, Lys-101 to Glu, and
Val-106 to Iso) associated with antiretroviral resistance were identified in RT
clones from HIV-1 group O-infected patients not subjected to drug therapy or
treated with unrelated drugs. Finally, phylogenetic relationships between RT
clones of the treated ESP2 patient and those of the untreated ESP1 patient show
how drug pressure can direct evolution of viral pol gene quasispecies
independently of direct drug-resistant substitutions.
PMID- 9765447
TI - The role of in vitro-induced lymphocyte apoptosis in feline immunodeficiency
virus infection: correlation with different markers of disease progression.
AB - Human immunodeficiency virus infection is characterized by a progressive decline
in the number of peripheral blood CD4(+) T lymphocytes, which finally leads to
AIDS. This T-cell decline correlates with the degree of in vitro-induced
lymphocyte apoptosis. However, such a correlation has not yet been described in
feline AIDS, caused by feline immunodeficiency virus (FIV) infection. We
therefore investigated the intensity of in vitro-induced apoptosis in peripheral
blood lymphocytes from cats experimentally infected with a Swiss isolate of FIV
for 1 year and for 6 years and from a number of long-term FIV-infected cats which
were coinfected with feline leukemia virus. Purified peripheral blood lymphocytes
were either cultured overnight under nonstimulating conditions or stimulated with
phytohemagglutinin and interleukin-2 for 60 h. Under stimulating conditions, the
isolates from the infected cats showed significantly higher relative counts of
apoptotic cells than did those from noninfected controls (1-year-infected cats, P
= 0.01; 6-year-infected cats, P = 0.006). The frequency of in vitro-induced
apoptosis was inversely correlated with the CD4(+) cell count (P = 0. 002),
bright CD8(+) cell count (P = 0.009), and CD4/CD8 ratio (P = 0. 01) and directly
correlated with the percentage of bright major histocompatibility complex class
II-positive peripheral blood lymphocytes (P = 0.004). However, we found no
correlation between in vitro-induced apoptosis and the viral load in serum
samples. Coinfection with feline leukemia virus enhanced the degree of in vitro
induced apoptosis compared with that in FIV monoinfected cats. We concluded that
the degree of in vitro-induced apoptosis was closely related to FIV-mediated T
cell depletion and lymphocyte activation and could be used as an additional
marker for disease progression in FIV infection.
PMID- 9765448
TI - Importance of basic residues in the nucleocapsid sequence for retrovirus Gag
assembly and complementation rescue.
AB - The Gag proteins of Rous sarcoma virus (RSV) and human immunodeficiency virus
(HIV) contain small interaction (I) domains within their nucleocapsid (NC)
sequences. These overlap the zinc finger motifs and function to provide the
proper density to viral particles. There are two zinc fingers and at least two I
domains within these Gag proteins. To more thoroughly characterize the important
sequence features and properties of I domains, we analyzed Gag proteins that
contain one or no zinc finger motifs. Chimeric proteins containing the amino
terminal half of RSV Gag and various portions of the carboxy terminus of murine
leukemia virus (MLV) (containing one zinc finger) Gag had only one I domain,
whereas similar chimeras with human foamy virus (HFV) (containing no zinc
fingers) Gag had at least two. Mutational analysis of the MLV NC sequence and
inspection of I domain sequences within the zinc-fingerless C terminus of HFV Gag
suggested that clusters of basic residues, but not the zinc finger motif residues
themselves, are required for the formation of particles of proper density. In
support of this, a simple string of strongly basic residues was found to be able
to substitute for the RSV I domains. We also explored the possibility that
differences in I domains (e.g., their number) account for differences in the
ability of Gag proteins to be rescued into particles when they are unable to bind
to membranes. Previously published experiments have shown that such membrane
binding mutants of RSV and HIV (two I domains) can be rescued but that those of
MLV (one I domain) cannot. Complementation rescue experiments with RSV-MLV
chimeras now map this difference to the NC sequence of MLV. Importantly, the same
RSV-MLV chimeras could be rescued by complementation when the block to budding
was after, rather than before, transport to the membrane. These results suggest
that MLV Gag molecules begin to interact at a much later time after synthesis
than those of RSV and HIV.
PMID- 9765449
TI - Neuronal death induced by brain-derived human immunodeficiency virus type 1
envelope genes differs between demented and nondemented AIDS patients.
AB - Human immunodeficiency virus type 1 (HIV-1) infection of the brain results in
viral replication primarily in macrophages and microglia. Despite frequent
detection of viral genome and proteins in the brains of AIDS patients with and
without HIV dementia, only 20% of AIDS patients become demented. To investigate
the role of viral envelope gene variation in the occurrence of dementia, we
examined regions of variability in the viral envelope gene isolated from brains
of AIDS patients. Brain-derived HIV-1 V1-V2 envelope sequences from seven
demented and six nondemented AIDS patients displayed significant sequence
differences between clinical groups, and by phylogenetic analysis, sequences from
the demented group showed clustering. Infectious recombinant viruses containing
brain-derived V3 sequences from both clinical groups were macrophagetropic, and
viruses containing brain-derived V1, V2, and V3 sequences from both clinical
groups spread efficiently in macrophages. In an indirect in vitro neurotoxicity
assay using supernatant fluid from HIV-1-infected macrophages, recombinant
viruses from demented patients induced greater neuronal death than viruses from
nondemented patients. Thus, the HIV-1 envelope diversity observed in these
patient groups appeared to influence the release of neurotoxic molecules from
macrophages and might account in part for the variability in occurrence of
dementia in AIDS patients.
PMID- 9765451
TI - A bipartite membrane-binding signal in the human immunodeficiency virus type 1
matrix protein is required for the proteolytic processing of Gag precursors in a
cell type-dependent manner.
AB - It is unclear whether proteolytic processing of the human immunodeficiency virus
type 1 (HIV-1) Gag protein is dependent on virus assembly at the plasma membrane.
Mutations that prevent myristylation of HIV-1 Gag proteins have been shown to
block virus assembly and release from the plasma membrane of COS cells but do not
prevent processing of Gag proteins. In contrast, in HeLa cells similar mutations
abolished processing of Gag proteins as well as virus production. We have now
addressed this issue with CD4(+) T cells, which are natural target cells of HIV
1. In these cells, myristylation of Gag proteins was required for proteolytic
processing of Gag proteins and production of extracellular viral particles. This
result was not due to a lack of expression of the viral protease in the form of a
Gag-Pol precursor or a lack of interaction between unmyristylated Gag and Gag-Pol
precursors. The processing defect of unmyristylated Gag was partially rescued ex
vivo by coexpression with wild-type myristylated Gag proteins in HeLa cells. The
cell type-dependent processing of HIV-1 Gag precursors was also observed when
another part of the plasma membrane binding signal, a polybasic region in the
matrix protein, was mutated. The processing of unmyristylated Gag precursors was
inhibited in COS cells by HIV-1 protease inhibitors. Altogether, our findings
demonstrate that the processing of HIV-1 Gag precursors in CD4(+) T cells occurs
normally at the plasma membrane during viral morphogenesis. The intracellular
environment of COS cells presumably allows activation of the viral protease and
proteolytic processing of HIV-1 Gag proteins in the absence of plasma membrane
binding.
PMID- 9765450
TI - Costimulation of naive CD8(+) lymphocytes induces CD4 expression and allows human
immunodeficiency virus type 1 infection.
AB - Human immunodeficiency virus type 1 (HIV-1) infection requires cell surface
expression of CD4. Costimulation of CD8(+)/CD4(-) T lymphocytes by anti-CD3 and
anti-CD28 antibodies or by allogeneic dendritic cells induced expression of CD4
and rendered these CD8 cells susceptible to HIV-1 infection. Naive CD45RA+ cells
responded with greater expression of CD4 than did CD45RO+ cells. CD8(+)
lymphocytes derived from fetal or newborn sources exhibited a greater tendency to
express CD4, consistent with their naive states. This mechanism of infection
suggests HIV-induced perturbation of the CD8 arm of the immune response and could
explain the generally rapid disease progression seen in HIV-infected children.
PMID- 9765452
TI - Oral immunization of macaques with attenuated vaccine virus induces protection
against vaginally transmitted AIDS.
AB - The chimeric simian-human immunodeficiency virus SHIVKU-1, bearing the envelope
of human immunodeficiency virus type 1 (HIV-1), causes fulminant infection with
subtotal loss of CD4(+) T cells followed by development of AIDS in intravaginally
inoculated macaques and thus provides a highly relevant model of sexually
transmitted disease caused by HIV-1 in human beings. Previous studies using this
SHIV model had shown that the vpu and nef genes were important in pathogenesis of
the infection, and so we deleted portions of these genes to create two vaccines,
DeltavpuDeltanefSHIV-4 (vaccine 1) and DeltavpuSHIVPPc (vaccine 2). Six adult
macaques were immunized subcutaneously with vaccine 1, and six were immunized
orally with vaccine 2. Both viruses caused infection in all inoculated animals,
but whereas vaccine 1 virus caused only a nonproductive type of infection,
vaccine 2 virus replicated productively but transiently for a 6- to 10-week
period. Both groups were challenged 6 to 7 months later with pathogenic SHIVKU-1
by the intravaginal route. All four unvaccinated controls developed low CD4(+) T
cell counts (<200/microliter) and AIDS. The 12 vaccinated animals all became
infected with SHIVKU-1, and two in group 1 developed a persistent productive
infection followed by development of AIDS in one. The other 10 have maintained
almost complete control over virus replication even though spliced viral RNA was
detected in lymph nodes. This suppression of virus replication correlated with
robust antiviral cell-mediated immune responses. This is the first demonstration
of protection against virulent SHIV administered by the intravaginal route. This
study supports the concept that sexually transmitted HIV disease can be prevented
by parenteral or oral immunization.
PMID- 9765453
TI - Structure and function of a ganglioside receptor for porcine rotavirus.
AB - A ganglioside fraction isolated from pooled intestines from newborn to 4-week-old
piglets, which we previously partially characterized and showed to specifically
inhibit the binding of porcine rotavirus (OSU strain) to host cells (M. D.
Rolsma, H. B. Gelberg, and M. S. Kuhlenschmidt, J. Virol. 68:258-268, 1994), was
further purified and found to contain two major monosialogangliosides. Each
ganglioside was purified to apparent homogeneity, and their carbohydrate
structure was examined by high-pH anion-exchange chromatography coupled with
pulsed amperometric detection and fast atom bombardment mass spectroscopy. Both
gangliosides possessed a sialyllactose oligosaccharide moiety characteristic of
GM3 gangliosides. Compositional analyses indicated that each ganglioside was
composed of sialic acid, galactose, glucose, and sphingosine in approximately a
1:1:1:1 molar ratio. Each ganglioside differed, however, in the type of sialic
acid residue it contained. An N-glycolylneuraminic acid (NeuGc) moiety was found
in the more polar porcine GM3, whereas the less polar GM3 species contained N
acetylneuraminic acid (NeuAc). Both NeuGcGM3 and NeuAcGM3 displayed dose
dependent inhibition of virus binding to host cells. NeuGcGM3 was approximately
two to three times more effective than NeuAcGM3 in blocking virus binding.
Inhibition of binding occurred with as little as 400 pmol of NeuGcGM3/50 ng of
virus (approximately 2 x 10(7) virions) and 2 x 10(6) cells/ml. Fifty percent
inhibition of binding was achieved with 0.64 and 1.5 microM NeuGcGM3 and
NeuAcGM3, respectively. The free oligosaccharides 3'- and 6'-sialyllactose
inhibited binding 50% at millimolar concentrations, which were nearly 1,000 times
the concentration of intact gangliosides required for the same degree of
inhibition. Direct binding of infectious, triple-layer rotavirus particles, but
not noninfectious, double-layered rotavirus particles, to NeuGcGM3 and NeuAcGM3
was demonstrated by using a thin-layer chromatographic overlay assay. NeuGcGM3
and NeuAcGM3 inhibited virus infectivity of MA-104 cells by 50% at concentrations
of 3.97 and 9. 84 microM, respectively. NeuGcGM3 (700 nmol/g [dry weight] of
intestine) was found to be the predominant enterocyte ganglioside (comprising 75%
of the total lipid-bound sialic acid) in neonatal piglets, followed by NeuAcGM3
(200 nmol/g [dry weight] of intestine). NeuGcGM3 and NeuAcGM3 together comprised
nearly 100% of the lipid-bound sialic acid in the neonatal intestine, but their
quantities rapidly diminished during the first 5 weeks of life. These data
support the hypothesis that porcine NeuGcGM3 and NeuAcGM3 are physiologically
relevant receptors for porcine rotavirus (OSU strain). Further support for this
hypothesis was obtained from virus binding studies using mutant or neuraminidase
treated cell lines. Lec-2 cells, a mutant clone of CHO cells characterized by a
90% reduction in sialyllation of its glycoconjugates, bound less than 5% of the
virus compared to control cell binding. In contrast, Lec-1 cells, a mutant CHO
clone characterized by a deficiency in glycosylation of N-linked
oligosaccharides, still bound rotavirus. Furthermore, exogenous addition of
NeuGcGM3 to the Lec-2 mutant cells restored their ability to bind rotavirus in
amounts equivalent to that of their parent (CHO) cell line. In the virus
permissive MA-104 cell line, NeuGcGM3 was also able to partially restore
rotavirus infectivity in neuraminidase-treated cells. These data suggest that
gangliosides play a major role in recognition of host cells by porcine rotavirus
(OSU strain).
PMID- 9765454
TI - Studies of the neutralizing activity and avidity of anti-human immunodeficiency
virus type 1 Env antibody elicited by DNA priming and protein boosting.
AB - DNA vaccination is an effective means of eliciting strong antibody responses to a
number of viral antigens. However, DNA immunization alone has not generated
persistent, high-titer antibody and neutralizing antibody responses to human
immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env). We have
previously reported that DNA-primed anti-Env antibody responses can be augmented
by boosting with Env-expressing recombinant vaccinia viruses. We report here that
recombinant Env protein provides a more effective boost of DNA-initiated antibody
responses. In rabbits primed with Env-expressing plasmids, protein boosting
increased titer, persistence, neutralizing activity, and avidity of anti-Env
responses. While titers increased rapidly after boosting, avidity and
neutralizing activity matured more slowly over a 6-month period following protein
boosting. DNA priming and protein immunization with HIV-1 HXB-2 Env elicited
neutralizing antibody for T cell line-adapted, but not primary isolate, viruses.
The most effective neutralizing antibody responses were observed after priming
with plasmids which expressed noninfectious virus-like particles. In contrast to
immunizations with HIV-1 Env, DNA immunizations with the influenza virus
hemagglutinin glycoprotein did not require a protein boost to achieve high-titer
antibody with good avidity and persistence.
PMID- 9765455
TI - Role of variable regions A and B in receptor binding domain of amphotropic murine
leukemia virus envelope protein.
AB - For the amphotropic murine leukemia virus (MuLV), a 208-amino-acid amino-terminal
fragment of the surface unit (SU) of the envelope glycoprotein is sufficient to
bind to its receptor, Pit2. Within this binding domain, two hypervariable
regions, VRA and VRB, have been proposed to be important for receptor
recognition. In order to specifically locate residues that are important for the
interaction with Pit2, we generated a number of site-specific mutations in both
VRA and VRB and analyzed the resulting envelope proteins when expressed on
retroviral vectors. Concurrently, we substituted portions of the amphotropic SU
with homologous regions from the polytropic MuLV envelope protein. The
amphotropic SU was unaffected by most of the point mutations we introduced. In
addition, the deletion of eight residues in a region of VRA that was previously
suggested to be essential for Pit2 utilization only decreased titer on NIH 3T3
cells by 1 order of magnitude. Although the replacement of the amino-terminal two
thirds of VRA with the polytropic sequence abolished receptor binding, smaller
nonoverlapping substitutions did not affect the function of the protein. We were
not able to identify a single critical receptor contact point within VRA, and we
suggest that the amphotropic receptor binding domain probably makes multiple
contacts with the receptor and that the loss of some of these contacts can be
tolerated.
PMID- 9765456
TI - Neurovirulence in feline immunodeficiency virus-infected neonatal cats is viral
strain specific and dependent on systemic immune suppression.
AB - Feline immunodeficiency virus (FIV) is a lentivirus that causes immune
suppression and neurological disease in cats. Among animal viruses, individual
viral strains have been shown to be neurovirulent, but the role of viral strain
specificity among lentiviruses and its relationship to systemic immune
suppression in the development of neurological disease remains uncertain. To
determine the extent to which different FIV strains caused neurological disease,
FIV V1CSF and Petaluma were compared in ex vivo assays and in vivo. Both viruses
infected and replicated in macrophage and mixed glial cell cultures at similar
levels, but V1CSF induced significantly greater neuronal death than Petaluma in a
neurotoxicity assay. V1CSF-infected animals showed significant neurodevelopmental
delay compared to the Petaluma-infected and uninfected animals. Magnetic
resonance spectroscopy studies of frontal cortex revealed significantly reduced N
acetyl aspartate/creatine ratios in the V1CSF group compared to the other groups.
Cyclosporin A treatment of Petaluma-infected animals caused neurodevelopmental
delay and reduced N-acetyl aspartate/creatine ratios in the brain. Reduced CD4(+)
and CD8(+) cell counts were observed in the V1CSF-infected group compared to the
uninfected and Petaluma-infected groups. These findings suggest that
neurodevelopmental delay and neuronal injury is FIV strain specific but that
systemic immune suppression is also an important determinant of FIV-induced
neurovirulence.
PMID- 9765457
TI - Duck hepatitis B virus nucleocapsids formed by N-terminally extended or C
terminally truncated core proteins disintegrate during viral DNA maturation.
AB - Hepadnaviruses are DNA viruses that replicate through reverse transcription of an
RNA pregenome. Viral DNA synthesis takes place inside viral nucleocapsids, formed
by core protein dimers. Previous studies have identified carboxy-terminal
truncations of the core protein that affect viral DNA maturation. Here, we
describe the effect of small amino-terminal insertions into the duck hepatitis B
virus (DHBV) core protein on viral DNA replication. All insertion mutants formed
replication-competent nucleocapsids. Elongation of viral DNA, however, appeared
to be incomplete. Increasing the number of additional amino acids and introducing
negatively charged residues further reduced the observed size of mature viral DNA
species. Mutant core proteins did not inhibit the viral polymerase. Instead,
viral DNA synthesis destabilized mutant nucleocapsids, rendering mature viral DNA
selectively sensitive to nuclease action. Interestingly, the phenotype of two
previously described carboxy-terminal DHBV core protein deletion mutants was
found to be based on the same mechanism. These data suggest that (i) the amino-
as well as the carboxy-terminal portion of the DHBV core protein plays a critical
role in nucleocapsid stabilization, and (ii) the hepadnavirus polymerase can
perform partial second-strand DNA synthesis in the absence of intact viral
nucleocapsids.
PMID- 9765458
TI - Receptor binding sites and antigenic epitopes on the fiber knob of human
adenovirus serotype 3.
AB - The adenovirus fiber knob causes the first step in the interaction of adenovirus
with cell membrane receptors. To obtain information on the receptor binding
site(s), the interaction of labeled cell membrane proteins to synthetic peptides
covering the adenovirus type 3 (Ad3) fiber knob was studied. Peptide P6 (amino
acids [aa] 187 to 200), to a lesser extent P14 (aa 281 to 294), and probably P11
(aa 244 to 256) interacted specifically with cell membrane proteins, indicating
that these peptides present cell receptor binding sites. Peptides P6, P11, and
P14 span the D, G, and I beta-strands of the R-sheet, respectively. The other
reactive peptides, P2 (aa 142 to 156), P3 (aa 153 to 167), and P16 (aa 300 to
319), probably do not present real receptor binding sites. The binding to these
six peptides was inhibited by Ad3 virion and was independent of divalent cations.
We have also screened the antigenic epitopes on the knob with recombinant Ad3
fiber, recombinant Ad3 fiber knob, and Ad3 virion-specific antisera by enzyme
linked immunosorbent assay. The main antigenic epitopes were presented by P3, P6,
P12 (aa 254 to 269), P14, and especially the C-terminal P16. Peptides P14 and P16
of the Ad3 fiber knob were able to inhibit Ad3 infection of cells.
PMID- 9765459
TI - The PK domain of the large subunit of herpes simplex virus type 2 ribonucleotide
reductase (ICP10) is required for immediate-early gene expression and virus
growth.
AB - The large subunit of herpes simplex virus (HSV) ribonucleotide reductase (RR),
RR1, contains a unique amino-terminal domain which has serine/threonine protein
kinase (PK) activity. To examine the role of the PK activity in virus
replication, we studied an HSV type 2 (HSV-2) mutant with a deletion in the RR1
PK domain (ICP10DeltaPK). ICP10DeltaPK expressed a 95-kDa RR1 protein (p95) which
was PK negative but retained the ability to complex with the small RR subunit,
RR2. Its RR activity was similar to that of HSV-2. In dividing cells, onset of
virus growth was delayed, with replication initiating at 10 to 15 h
postinfection, depending on the multiplicity of infection. In addition to the
delayed growth onset, virus replication was significantly impaired (1,000-fold
lower titers) in nondividing cells, and plaque-forming ability was severely
compromised. The RR1 protein expressed by a revertant virus [HSV-2(R)] was
structurally and functionally similar to the wild-type protein, and the virus had
wild-type growth and plaque-forming properties. The growth of the ICP10DeltaPK
virus and its plaque-forming potential were restored to wild-type levels in cells
that constitutively express ICP10. Immediate-early (IE) genes for ICP4, ICP27,
and ICP22 were not expressed in Vero cells infected with ICP10DeltaPK early in
infection or in the presence of cycloheximide, and the levels of ICP0 and p95
were significantly (three- to sevenfold) lower than those in HSV-2- or HSV-2(R)
infected cells. IE gene expression was similar to that of the wild-type virus in
cells that constitutively express ICP10. The data indicate that ICP10 PK is
required for early expression of the viral regulatory IE genes and, consequently,
for timely initiation of the protein cascade and HSV-2 growth in cultured cells.
PMID- 9765461
TI - Epstein-Barr virus contributes to the malignant phenotype and to apoptosis
resistance in Burkitt's lymphoma cell line Akata.
AB - In the present study, we established an in vitro system representing the
Burkitt's lymphoma (BL)-type Epstein-Barr virus (EBV) infection which is
characterized by expression of EBV-determined nuclear antigen 1 (EBNA-1) and
absence of EBNA-2 and latent membrane protein 1 (LMP1) expression. EBV-negative
cell clones isolated from the EBV-positive BL line Akata were infected with an
EBV recombinant carrying a selectable marker, and the following selection culture
easily yielded EBV-infected clones. EBV-reinfected clones showed BL-type EBV
expression and restored the capacity for growth on soft agar and tumorigenicity
in SCID mice that were originally retained in parental EBV-positive Akata cells
and lost in EBV-negative subclones. Moreover, it was found that EBV-positive
cells were more resistant to apoptosis than were EBV-negative cells. EBV-infected
cells expressed the bcl-2 protein, through which cells might become resistant to
apoptosis, at a higher level than did uninfected cells. This is the first report
that BL-type EBV infection confers apoptosis resistance even in the absence of
expression of LMP1 and BHRF1, both of which are known to have an antiapoptotic
function. Surprisingly, transfection of the EBNA-1 gene into EBV-negative Akata
clones could not restore malignant phenotypes and apoptosis resistance, thus
suggesting that EBNA-1 alone was not sufficient for conferring them. Our results
suggest that the persistence of EBV in BL cells is required for the cells to be
more malignant and apoptosis resistant, which underlines the oncogenic role of
EBV in BL genesis.
PMID- 9765460
TI - Characterization of a baculovirus-encoded ATP-dependent DNA ligase.
AB - Sequence analysis of the Lymantria dispar multicapsid nucleopolyhedrovirus
(LdMNPV) genome identified an open reading frame (ORF) encoding a 548-amino-acid
(62-kDa) protein that showed 35% amino acid sequence identity with vaccinia virus
ATP-dependent DNA ligase. Ligase homologs have not been reported from other
baculoviruses. The ligase ORF was cloned and expressed as an N-terminal histidine
tagged fusion protein. Incubation of the purified protein with [alpha-32P]ATP
resulted in formation of a covalent enzyme-adenylate intermediate which ran as a
62-kDa labeled band on a sodium dodecyl sulfate-polyacrylamide gel. Loss of the
radiolabeled band occurred upon incubation of the intermediate with
pyrophosphate, poly(dA) . poly(dT)12-18, or poly(rA) . poly(dT)12-18,
characteristics of a DNA ligase II or III. The protein was able to ligate a
double-stranded synthetic DNA substrate containing a single nick and
inefficiently ligated a 1-nucleotide (nt) gap but did not ligate a 2-nt gap. It
was able to ligate short, complementary overhangs but not blunt-ended double
stranded DNA. In a transient DNA replication assay employing six plasmids
containing the LdMNPV homologs of the essential baculovirus replication genes, a
plasmid containing the DNA ligase gene was neither essential nor stimulatory. All
of these results are consistent with the activity of type III DNA ligases, which
have been implicated in DNA repair and recombination.
PMID- 9765462
TI - Persistent baculovirus infection results from deletion of the apoptotic
suppressor gene p35.
AB - Infection with the wild-type baculovirus Autographa californica multiple nuclear
polyhedrosis virus (AcMNPV) results in complete death of Spodoptera frugiperda
(Sf) cells. However, infection of Sf cells with AcMNPV carrying a mutation or
deletion of the apoptotic suppressor gene p35 allowed the cloning of surviving Sf
cells that harbored persistent viral genomes. Persistent infection established
with the virus with p35 mutated or deleted was blocked by stable transfection of
p35 in the host genome or by insertion of the inhibitor of apoptosis (iap) gene
into the viral genome. These artificially established persistently virus-infected
cells became resistant to subsequent viral challenge, and some of the cell lines
carried large quantities of viral DNA capable of early gene expression.
Continuous release of viral progenies was evident in some of the persistently
virus-infected cells, and transfection of p35 further stimulated viral activation
of the persistent cells, including the reactivation of viruses in those cell
lines without original continuous virus release. These results have demonstrated
the successful establishment of persistent baculovirus infections under
laboratory conditions and that their establishment may provide a novel
continuous, nonlytic baculovirus expression system in the future.
PMID- 9765463
TI - Persistence of herpes simplex virus type 1 DNA in chronic conjunctival and eyelid
lesions of mice.
AB - Herpes simplex virus type 1 (HSV-1) causes chronic blepharitis and conjunctivitis
as well as keratitis in humans. The pathogenesis of these inflammatory ocular and
dermal lesions is not well understood. We have examined the persistence of HSV-1
DNA and its relationship to inflammatory lesions in the conjunctiva and eyelid
skin of mice which were inoculated with HSV-1 by the corneal route. Viral DNA was
detected by in situ PCR in the conjunctiva and eyelid tissue of infected mice at
5, 11, 23, and 37 days postinfection (p.i.). This DNA was localized in the
epithelial cells of the conjunctiva and hair follicles and in the epidermal cells
of the eyelid skin. Viral proteins were not detected in the conjunctiva or the
eyelid skin after 5 days p.i., even though histopathological lesions were found
at 23 and 37 days p.i. in both tissues. The DNA-containing cells were adjacent to
sites of inflammation in the chronic lesions in both the conjunctiva and the
eyelid skin. A similar temporal and spatial relationship between HSV-1 DNA and
inflammatory lesions has been previously reported for the cornea. Our data
suggest that the lesions in the cornea, conjunctiva, and eyelid skin progress
similarly. Further studies are required to determine whether the long-term
presence of HSV-1 is involved in the mechanism by which these chronic
inflammatory lesions develop. The presence of HSV-1 DNA in these extraocular
tissues for extended periods may constitute persistent viral infection of
nonneuronal cells.
PMID- 9765464
TI - Extracellular signal-regulated kinase activity is sustained early during human
cytomegalovirus infection.
AB - Expression of many early viral genes during human cytomegalovirus (HCMV)
infection is dependent on cellular transcription factors. Several immediate-early
and early viral promoters contain DNA binding sites for cellular factors such as
CREB, AP-1, serum response factor, and Elk-1, and these transcription factors can
be activated by phosphorylation via the cellular mitogen-activated protein kinase
(MAPK) signal transduction cascade. To determine if the extracellular signal
regulated MAPKs, ERK1 and ERK2, play a role in transcription factor activation
during infection, we tested for ERK activity during viral infection. We found
that HCMV infection resulted in the maintenance of previously activated ERK1 and
ERK2 by a mechanism which appears to involve the inhibition of a cellular
phosphatase activity. ERK phosphorylation and activity were sustained for at
least 8 h after infection, whereas in mock-infected cells, ERK activity steadily
declined by 1 h postinfection. The activity of at least one cellular substrate of
the ERKs, the protein kinase RSK1, was also maintained during this period. UV
inactivation experiments suggested that viral gene expression was required for
sustained ERK activity. In turn, activation of the ERKs appeared to be important
for viral gene expression, as evidenced by the observed decrease in the
transcriptional activity of the HCMV UL112-113 promoter during infection in the
presence of the MEK inhibitor PD98059. These data suggest that HCMV utilizes
cellular signal transduction pathways to activate viral or cellular transcription
factors involved in the control of early viral gene expression and DNA
replication.
PMID- 9765465
TI - Pseudorabies virus-induced leukocyte trafficking into the rat central nervous
system.
AB - When the swine alphaherpesvirus pseudorabies virus (PRV) infects the rat retina,
it replicates in retinal ganglion cells and invades the central nervous system
(CNS) via anterograde transynaptic spread through axons in the optic nerve. Virus
can also spread to the CNS via retrograde transport through the oculomotor
nucleus that innervates extraocular muscles of the eye. Since retrograde
infection of the CNS precedes anterograde transynaptic infection, the temporal
sequence of infection of the CNS depends on the route of invasion. Thus, motor
neurons are infected first (retrograde infection), followed by CNS neurons
innervated by the optic nerve (anterograde transynaptic infection). This temporal
separation in the appearance of virus in separate groups of neurons enabled us to
compare the immune responses to different stages of CNS infection in the same
animal. The data revealed focal trafficking of peripheral immune cells into areas
of the CNS infected by retrograde or anterograde transport after PRV Becker was
injected into the vitreous body of the eye. Cells expressing the leukocyte common
antigen, CD45(+), entered the area of infection from local capillaries prior to
any overt expression of neuropathology, and quantitative analysis demonstrated
that the number of cells increased in proportion to the number of infected
neurons within a given region. Recruitment of cells of monocyte/macrophage
lineage began prior to the appearance of CD8(+) cytotoxic lymphocytes, which
were, in turn, followed by CD4(+) lymphocytes. These data demonstrate that PRV
replication in CNS neurons stimulates the focal infiltration of specific classes
of CD45(+) cells in a time-dependent, temporally organized fashion that is
correlated directly with the number of infected neurons and the time that a given
region has been infected.
PMID- 9765466
TI - Mutations in the N terminus of the brome mosaic virus polymerase affect genetic
RNA-RNA recombination.
AB - Previously, we have observed that mutations in proteins 1a and 2a, the two
virally encoded components of the brome mosaic virus (BMV) replicase, can affect
the frequency of recombination and the locations of RNA recombination sites (P.
D. Nagy, A. Dzianott, P. Ahlquist, and J. J. Bujarski, J. Virol. 69:2547-2556,
1995; M. Figlerowicz, P. D. Nagy, and J. J. Bujarski, Proc. Natl. Acad. Sci. USA
94:2073-2078, 1997). Also, it was found before that the N-terminal domain of 2a,
the putative RNA polymerase protein, participates in the interactions between 1a
and 2a (C. C. Kao, R. Quadt, R. P. Hershberger, and P. Ahlquist, J. Virol.
66:6322-6329, 1992; E. O'Reilly, J. Paul, and C. C. Kao, J. Virol. 71:7526-7532,
1997). In this work, we examine how mutations within the N terminus of 2a
influence RNA recombination in BMV. Because of the likely electrostatic character
of 1a-2a interactions, five 2a mutants, MF1 to MF5, were generated by replacing
clusters of acidic amino acids with their neutral counterparts. MF2 and MF5
retained nearly wild-type levels of 1a-2a interaction and were infectious in
Chenopodium quinoa. However, compared to that in wild-type virus, the frequency
of nonhomologous recombination in both MF2 and MF5 was markedly decreased. Only
in MF2 was the frequency of homologous recombination reduced and the occurrence
of imprecise homologous recombination increased. In MF5 there was also a 3' shift
in the positions of homologous crossovers. The observed effects of MF2 and MF5
reveal that the 2a N-terminal domain participates in different ways in homologous
and in nonhomologous BMV RNA recombination. This work maps specific locations
within the N terminus involved in 1a-2a interaction and in recombination and
further suggests that the mechanisms of the two types of crossovers in BMV are
different.
PMID- 9765467
TI - Combination gene delivery of the cell cycle inhibitor p27 with thymidine kinase
enhances prodrug cytotoxicity.
AB - Cytoxicity induced by the herpesvirus thymidine kinase (TK) gene in combination
with prodrugs is dependent on cell growth and leads to the elimination of
genetically modified cells, thus limiting the duration of expression and efficacy
of this treatment in vivo. Here, an effort was made to enhance TK/prodrug
efficacy by coexpression of a cyclin-dependent kinase inhibitor (CKI), p27, to
render cells resistant to TK/prodrug by inhibiting DNA synthesis. Expression of
p27 by transfection substantially reduced cell cycle progression, and its
activity was enhanced by mutations designed to stabilize the protein.
Coexpression of p27 and TK or a p27/TK fusion protein led to greater prodrug
cytotoxicity than that produced by TK alone in the Renca cell line, which is
sensitive to bystander killing. Combination gene transfer of this CKI with TK
therefore sustained the synthesis of TK by genetically modified cells to enhance
the susceptibility of bystander cells to prodrug cytotoxicity and increased the
efficacy of this gene transfer approach.
PMID- 9765468
TI - Evidence for an underlying CD4 helper and CD8 T-cell defect in B-cell-deficient
mice: failure to clear persistent virus infection after adoptive immunotherapy
with virus-specific memory cells from muMT/muMT mice.
AB - Adoptive transfer of virus-specific memory lymphocytes can be used to identify
factors and mechanisms involved in the clearance of persistent virus infections.
To analyze the role of B cells in clearing persistent infection with lymphocytic
choriomeningitis virus (LCMV), we used B-cell-deficient muMT/muMT (B-/-) mice. B
/- mice controlled an acute LCMV infection with the same kinetics and efficiency
as B-cell-competent (B+/+) mice via virus-specific, major histocompatibility
complex (MHC) class I-restricted CD8(+) cytotoxic T lymphocytes (CTL). CTL from B
/- and B+/+ mice were equivalent in affinity to known LCMV CTL epitopes and had
similar CTL precursor frequencies (pCTL). Adoptive transfer of memory cells from
B+/+ mice led to virus clearance from persistently infected B+/+ recipients even
after in vitro depletion of B cells, indicating that B cells or immunoglobulins
are not required in the transfer population. In contrast, transfer of memory
splenocytes from B-/- mice failed to clear virus. Control of virus was restored
neither by transferring higher numbers of pCTL nor by supplementing B-/- memory
splenocytes with LCMV-immune B cells or immune sera. Instead, B-/- mice were
found to have a profound CD4 helper defect. Furthermore, compared to cultured
splenocytes from B+/+ mice, those from B-/- mice secreted less gamma interferon
(IFN-gamma) and interleukin 2, with differences most pronounced for CD8 T cells.
While emphasizing the importance of CD4 T-cell help and IFN-gamma in the control
of persistent infections, the CD4 T-helper and CD8 T-cell defects in B-/- mice
suggest that B cells contribute to the induction of competent T effector cells.
PMID- 9765469
TI - The 5' and 3' TAR elements of human immunodeficiency virus exert effects at
several points in the virus life cycle.
AB - The human immunodeficiency virus type 1 RNA genome contains a terminal repeat (R)
sequence that encodes the TAR hairpin motif, which has been implicated in Tat
mediated activation of transcription. More recently, a variety of other functions
have been proposed for this structured RNA element. To determine the replicative
roles of the 5' and 3' TAR hairpins, we analyzed multiple steps in the life cycle
of wild-type and mutant viruses. A structure-destabilizing mutation was
introduced in either the 5', the 3', or both TAR motifs of the proviral genome.
As expected, opening of the 5' TAR hairpin caused a transcription defect. Because
the level of protein expression was not similarly reduced, the translation of
this mRNA was improved. No effect of the 3' hairpin on transcription and
translation was measured. Mutations of the 5' and 3' hairpin structures reduced
the efficiency of RNA packaging to similar extents, and RNA packaging was further
reduced in the 5' and 3' TAR double mutant. Upon infection of cells with these
virions, a reduced amount of reverse transcription products was synthesized by
the TAR mutant. However, no net reverse transcription defect was observed after
correction for the reduced level of virion RNA. This result was confirmed in in
vitro reverse transcription assays. These data indicate that the 5' and 3' TAR
motifs play important roles in several steps of the replication cycle, but these
structures have no significant effect on the mechanism of reverse transcription.
PMID- 9765470
TI - Molecular evidence for distinct genotypes of monkey B virus (herpesvirus simiae)
which are related to the macaque host species.
AB - Although monkey B virus (herpesvirus simiae; BV) is common in all macaque
species, fatal human infections appear to be associated with exposure to rhesus
macaques (Macaca mulatta), suggesting that BV isolates from rhesus monkeys may be
more lethal to nonmacaques than are BV strains indigenous to other macaque
species. To determine if significant differences that would support this
supposition exist among BV isolates, we compared multiple BV strains isolated
from rhesus, cynomolgus, pigtail, and Japanese macaques. Antigenic analyses
indicated that while the isolates were very closely related to one another, there
are some antigenic determinants that are specific to BV isolates from different
macaque species. Restriction enzyme digest patterns of viral DNA revealed marked
similarities between rhesus and Japanese macaque isolates, while pigtail and
cynomolgus macaque isolates had distinctive cleavage patterns. To further compare
genetic diversity among BV isolates, DNA sequences from two regions of the viral
genome containing genes that are conserved (UL27 and US6) and variable (US4 and
US5) among primate alphaherpesviruses, as well as from two noncoding intergenic
regions, were determined. From these sequence data and a phylogenetic analysis of
them it was evident that while all isolates were closely related strains of BV,
there were three distinct genotypes. The three BV genotypes were directly related
to the macaque species of origin and were composed of (i) isolates from rhesus
and Japanese macaques, (ii) cynomolgus monkey isolates, and (iii) isolates from
pigtail macaques. This study demonstrates the existence of different BV genotypes
which are related to the macaque host species and thus provides a molecular basis
for the possible existence of BV isolates which vary in their levels of
pathogenicity for nonmacaque species.
PMID- 9765471
TI - Subunit rotavirus vaccine administered parenterally to rabbits induces active
protective immunity.
AB - Virus-like particles (VLPs) are being evaluated as a candidate rotavirus vaccine.
The immunogenicity and protective efficacy of different formulations of VLPs
administered parenterally to rabbits were tested. Two doses of VLPs (2/6-, G3
2/6/7-, or P[2], G3 2/4/6/7-VLPs) or SA11 simian rotavirus in Freund's adjuvants,
QS-21 (saponin adjuvant), or aluminum phosphate (AlP) were administered.
Serological and mucosal immune responses were evaluated in all vaccinated and
control rabbits before and after oral challenge with 10(3) 50% infective doses of
live P[14], G3 ALA lapine rotavirus. All VLP- and SA11-vaccinated rabbits
developed high levels of rotavirus-specific serum and intestinal immunoglobulin G
(IgG) antibodies but not intestinal IgA antibodies. SA11 and 2/4/6/7-VLPs
afforded similar but much higher mean levels of protection than 2/6/7- or 2/6
VLPs in QS-21. The presence of neutralizing antibodies to VP4 correlated (P <
0.001, r = 0.55; Pearson's correlation coefficient) with enhanced protection
rates, suggesting that these antibodies are important for protection. Although
the inclusion of VP4 resulted in higher mean protection levels, high levels of
protection (87 to 100%) from infection were observed in individual rabbits
immunized with 2/6/7- or 2/6-VLPs in Freund's adjuvants. Therefore, neither VP7
nor VP4 was absolutely required to achieve protection from infection in the
rabbit model when Freund's adjuvant was used. Our results show that VLPs are
immunogenic when administered parenterally to rabbits and that Freund's adjuvant
is a better adjuvant than QS-21. The use of the rabbit model may help further our
understanding of the critical rotavirus proteins needed to induce active
protection. VLPs are a promising candidate for a parenterally administered
subunit rotavirus vaccine.
PMID- 9765472
TI - The bipartite geminivirus coat protein aids BR1 function in viral movement by
affecting the accumulation of viral single-stranded DNA.
AB - The movement of bipartite geminiviruses such as squash leaf curl virus (SqLCV)
requires the cooperative interaction of two essential virus-encoded movement
proteins, BR1 and BL1. While the viral coat protein AR1 is not essential for
systemic infection, genetic studies demonstrate that its presence masks the
defective phenotype of certain BR1 missense mutants, thus suggesting that coat
protein does interact with the viral movement pathway. To further examine the
mechanism of this interaction, we have constructed alanine-scanning mutants of
AR1 and studied them for the ability to mask the infectivity defects of
appropriate BR1 mutants, for the ability to target to the nucleus and to bind
viral single-stranded DNA (ssDNA) and multimerize, and for effects on the
accumulation of replicated viral ssDNA. We identified a specific region of AR1
required for masking of appropriate BR1 mutants and showed that this same region
of AR1 was also important for ssDNA binding and the accumulation of viral
replicated ssDNA. This region of AR1 also overlapped that involved in
multimerization of the coat protein. We also found that the accumulation in
protoplasts of single-stranded forms of a recombinant plasmid that included the
SqLCV replication origin but was too large to be encapsidated was dependent on
the presence of AR1 but did not appear to require encapsidation. These findings
extend our model for SqLCV movement, demonstrating that coat protein affects
viral movement through its ability to induce the accumulation of replicated viral
ssDNA genomes. They further suggested that encapsidation was not required for the
AR1-dependent accumulation of viral ssDNA.
PMID- 9765473
TI - Adenovirus induction of an interferon-regulatory factor during entry into the
late phase of infection.
AB - Virus infection of animal cells can induce intracellular antiviral responses
mediated by the induction of interferon-regulatory transcription factors (IRFs),
which bind to and control genes directed by the interferon-stimulated response
element (ISRE). The purpose of this study was to determine whether adenovirus
(Ad) induces IRFs during infection, because they might play a role in promoting
viral pathogenesis. Here we show that after the late phase of infection, Ad
induces a transcription factor related to the IRF family of factors. The IRF is
induced shortly after Ad entry into late phase and is shown to stimulate ISRE
directed transcription, to require activation by protein tyrosine kinase
signalling, and to be induced several hours prior to the inhibition of cell
protein synthesis. Inhibition of tyrosine kinase activity blocks Ad induction and
activation of the IRF. Attempts to identify the Ad-induced factor immunologically
and by photo-UV cross-linking indicate that it is likely a novel member of the
IRF family. Finally, several independent lines of evidence also suggest that Ad
induction of the IRF might correlate with the ability of the virus to block host
cell protein synthesis later during infection.
PMID- 9765474
TI - Inhibition of NF-kappaB activation in combination with bcl-2 expression allows
for persistence of first-generation adenovirus vectors in the mouse liver.
AB - NF-kappaB is a key regulator of the innate antiviral immune response, due in part
to its transcriptional activation of cytokines and adhesion molecules, which, in
turn, function in chemotaxis and activation of inflammatory cells. We reported
earlier that viral gene expression in hepatocytes transduced with first
generation (E1-deleted) adenoviruses induced NF-kappaB activation, elevation of
serum cytokines, and hepatocellular apoptosis during the first days postinfusion.
These events did not occur in mice infused with an adenovirus vector deleted for
E1, E2, E3, and late gene expression. In the present study, we used an adenovirus
expressing an IkappaBalpha supersuppressor (Ad.IkappaBM) and bcl-2 transgenic
mice to unravel the role of virus-induced NF-kappaB activation and apoptosis in
the clearance of recombinant adenovirus vectors from the liver. The combined
action of IkappaBM and Bcl-2 allowed for vector persistence in livers of C57BL/6
x C3H mice. In the absence of Bcl-2, IkappaBM expression in mouse livers
significantly reduced NF-kappaB activation, cytokine expression, leukocyte
infiltration, and the humoral immune response against the transgene product;
however, this was not sufficient to prevent the decline of vector DNA in
transduced cells. Infusion of Ad.IkappaBM caused extended apoptosis predominantly
in periportal liver regions, indicating that NF-kappaB activation may protect
transduced hepatocytes from apoptosis induced by adenovirus gene products. To
confer vector persistence, bcl-2 transgene expression was required to block virus
induced apoptosis if NF-kappaB protection was inactivated by IkappaBM. Expression
of gene products involved in early stages of apoptotic pathways was up-regulated
in response to virus infusion in bcl-2 transgenic mice, which may represent a
compensatory effect. Our study supports the idea that the suppression of innate
defense mechanisms improves vector persistence.
PMID- 9765475
TI - Transcriptional organization of the avian adenovirus CELO.
AB - A detailed map of the transcriptional organization of the CELO virus genome was
produced. Recent computer analysis of CELO virus has indicated the presence of 38
putative open reading frames (ORFs). This study, based on analysis of the
transcriptional products of CELO in vitro, confirmed the presence of RNAs for 26
of these 38 ORFs. All of the results were obtained by cDNA isolation or specific
reverse transcriptase PCR. Observation of ORF transcription kinetics
postinfection revealed the existence of early and late expression, with the
earliest starting at 2 h postinfection. The 5' untranslated regions of some RNAs
were also studied, and this revealed the existence of a bipartite leader
sequence, comparable in structure to the tripartite leader of mastadenovirus. The
leader most probably involved in transcriptional activity was observed in most of
the structural protein genes of the CELO virus genome. This suggests some
homology in transcriptional organization between the avian adenovirus CELO and
known mastadenoviruses such as human adenovirus.
PMID- 9765476
TI - Murine coronavirus-induced subacute fatal peritonitis in C57BL/6 mice deficient
in gamma interferon.
AB - Gamma interferon-deficient (IFN-gamma-/-) mice with a C57BL/6 background were
infected intraperitoneally with mouse hepatitis virus strain JHM (JHMV). In
contrast to IFN-gamma-+/- and IFN-gamma+/+ mice, JHMV persisted in IFN-gamma-/-
mice and induced death during the subacute phase of the infection. Unexpectedly,
infected IFN-gamma-/- mice showed severe peritonitis accompanying the
accumulation of a viscous fluid in the abdominal and thoracic cavities in the
subacute phase. Destructive changes of hepatocytes were not observed.
Administration of recombinant IFN-gamma protracted the survival time of IFN-gamma
/- mice after JHMV infection. These results demonstrate that IFN-gamma plays a
critical role in viral clearance in JHMV infection. They also show that a
resultant persistent JHMV infection induces another form of disease in IFN-gamma
/- mice, which bears a resemblance to feline infectious peritonitis in cats.
PMID- 9765477
TI - Equine endothelial cells support productive infection of equine infectious anemia
virus.
AB - Previous cell infectivity studies have demonstrated that the lentivirus equine
infectious anemia virus (EIAV) infects tissue macrophages in vivo and in vitro.
In addition, some strains of EIAV replicate to high titer in vitro in equine
fibroblasts and fibroblast cell lines. Here we report a new cell type,
macrovascular endothelial cells, that is infectible with EIAV. We tested the
ability of EIAV to infect purified endothelial cells isolated from equine
umbilical cords and renal arteries. Infectivity was detected by cell supernatant
reverse transcriptase positivity, EIAV antigen positivity within individual
cells, and the detection of viral RNA by in situ hybridization. Virus could
rapidly spread through the endothelial cultures, and the supernatants of infected
cultures contained high titers of infectious virus. There was no demonstrable
cell killing in infected cultures. Three of four strains of EIAV that were tested
replicated in these cultures, including MA-1, a fibroblast-tropic strain, Th.1, a
macrophage-tropic strain, and WSU5, a strain that is fibroblast tropic and can
cause disease. Finally, upon necropsy of a WSU5-infected horse 4 years
postinfection, EIAV-positive endothelial cells were detected in outgrowths of
renal artery cultures. These findings identify a new cell type that is infectible
with EIAV. The role of endothelial cell infection in the course of equine
infectious anemia is currently unknown, but endothelial cell infection may be
involved in the edema that can be associated with infection. Furthermore, the
ability of EIAV to persistently infect endothelial cultures and the presence of
virus in endothelial cells from a long-term carrier suggest that this cell type
can serve as a reservoir for the virus during subclinical phases of infection.
PMID- 9765478
TI - Development of a heterologous model in germfree suckling rats for studies of
rotavirus diarrhea.
AB - Germfree suckling rats were infected with an SA11 rotavirus strain. Infected pups
developed diarrhea associated with histopathological changes. The virus was
detected in feces and in the small intestine. Cellular vacuolation was observed
in the villi of the jejunum. These results provide a new model for further
investigations of group A rotavirus infection.
PMID- 9765479
TI - Use of a prenylation inhibitor as a novel antiviral agent.
AB - No specific therapy exists for hepatitis delta virus (HDV), which can cause
severe liver disease. Molecular genetic studies have implicated the prenylation
site of large delta antigen as a critical determinant of HDV particle assembly.
We have established a cell culture model which produces HDV-like particles, and
we show that delta antigen prenylation can be pharmacologically inhibited by the
prenylation inhibitor BZA-5B. Furthermore, BZA-5B specifically abolishes particle
production in a dose-dependent manner. These results demonstrate that the use of
such a prenylation inhibitor-based antiviral therapy may be feasible and identify
a novel class of potential antiviral agents.
PMID- 9765480
TI - Chemokine coreceptor usage by diverse primary isolates of human immunodeficiency
virus type 1.
AB - We tested chemokine receptor subset usage by diverse, well-characterized primary
viruses isolated from peripheral blood by monitoring viral replication with CCR1,
CCR2b, CCR3, CCR5, and CXCR4 U87MG.CD4 transformed cell lines and
STRL33/BONZO/TYMSTR and GPR15/BOB HOS.CD4 transformed cell lines. Primary viruses
were isolated from 79 men with confirmed human immunodeficiency virus type 1 (HIV
1) infection from the Chicago component of the Multicenter AIDS Cohort Study at
interval time points. Thirty-five additional well-characterized primary viruses
representing HIV-1 group M subtypes A, B, C, D, and E and group O and three
primary simian immunodeficiency virus (SIV) isolates were also used for these
studies. The restricted use of the CCR5 chemokine receptor for viral entry was
associated with infection by a virus having a non-syncytium-inducing phenotype
and correlated with a reduced rate of disease progression and a prolonged disease
free interval. Conversely, broadening chemokine receptor usage from CCR5 to both
CCR5 and CXCR4 was associated with infection by a virus having a syncytium
inducing phenotype and correlated with a faster rate of CD4 T-cell decline and
progression of disease. We also observed a greater tendency for infection with a
virus having a syncytium-inducing phenotype in men heterozygous for the defective
CCR5 Delta32 allele (25%) than in those men homozygous for the wild-type CCR5
allele (6%) (P = 0.03). The propensity for infection with a virus having a
syncytium-inducing phenotype provides a partial explanation for the rapid disease
progression among some men heterozygous for the defective CCR5 Delta32 allele.
Furthermore, we did not identify any primary viruses that used CCR3 as an entry
cofactor, despite this CC chemokine receptor being expressed on the cell surface
at a level commensurate with or higher than that observed for primary peripheral
blood mononuclear cells. Whereas isolates of primary viruses of SIV also used
STRL33/BONZO/TYMSTR and GPR15/BOB, no primary isolates of HIV-1 used these
particular chemokine receptor-like orphan molecules as entry cofactors,
suggesting a limited contribution of these other chemokine receptors to viral
evolution. Thus, despite the number of chemokine receptors implicated in viral
entry, CCR5 and CXCR4 are likely to be the physiologically relevant chemokine
receptors used as entry cofactors in vivo by diverse strains of primary viruses
isolated from blood.
PMID- 9765481
TI - The C-terminal half of the human immunodeficiency virus type 1 Gag precursor is
sufficient for efficient particle assembly.
AB - Human immunodeficiency virus type 1 particle assembly is directed by the Gag
polyprotein Pr55(gag), the precursor for the matrix (MA), capsid (CA), and
nucleocapsid proteins of the mature virion. We now show that CA sequences N
terminal to the major homology region (MHR), which form a distinct domain, are
dispensable for particle formation. However, slightly larger deletions which
extend into the MHR severely impair particle production. Remarkably, a deletion
which removed essentially all MA and CA sequences between the N-terminal myristyl
anchor and the MHR reduced the yield of extracellular particles only moderately.
Particle formation even exceeded wild-type levels when additional MA sequences,
either from the N or the C terminus of the domain, were retained. We conclude
that no distinct region between the myristyl anchor and the MHR is required for
efficient particle assembly or release.
PMID- 9765482
TI - A map of interactions between the proteins of a retrotransposon.
AB - The yeast two-hybrid system and in vitro binding assays were used to characterize
54 potential interactions between the proteins of Tf1, an LTR-retrotransposon
found in Schizosaccharomyces pombe. The Tf1 integrase (IN) protein was found to
interact strongly with itself and not with other control proteins. In addition,
the IN core domain interacted strongly with itself and full-length IN.
Interestingly, the two-hybrid analysis detected an interaction between the RNase
H domain of reverse transcriptase and IN. The biological implications of these
interactions are discussed.
PMID- 9765483
TI - Epstein-Barr virus small RNA (EBER) genes: differential regulation during lytic
viral replication.
AB - In every latently Epstein-Barr virus-infected cell the viral genes EBER-1 and
EBER-2 are transcribed by polymerase III. In lytically infected cells in vivo the
EBER genes could not be detected. However, in cell culture downregulation could
not be confirmed, and hence the relevance of this shutdown to the replication of
the virus was not clear. We assayed the transcriptional activity of the EBER
genes by nuclear run-on assays with enriched lytically infected cells and
demonstrated that EBER-1 and EBER-2 are differentially downregulated on the
transcriptional level during the switch to lytic viral replication. This
downregulation was an early event during the lytic replication of the virus.
PMID- 9765484
TI - Level of ICAM-1 surface expression on virus producer cells influences both the
amount of virion-bound host ICAM-1 and human immunodeficiency virus type 1
infectivity.
AB - Using virions harvested from 293T cells stably expressing either low or high
levels of surface ICAM-1, we determined that the number of virus-embedded host
ICAM-1 proteins is positively influenced by the expression level of ICAM-1 on
virus producer cells. Moreover, the increase in virion-bound host cell membrane
ICAM-1 led to a concomitant enhancement of virus infectivity when a T-cell-tropic
strain of human immunodeficiency virus type 1 (HIV-1) was used. The phenomenon
was also seen when primary human cells were infected with virions pseudotyped
with the envelope protein from a macrophage-tropic HIV-1 isolate, thus ruling out
any envelope-specific effect. We also observed that target cells treated with NKI
L16, an anti-LFA-1 antibody known to increase the affinity of LFA-1 for ICAM-1,
were markedly more susceptible to infection with HIV-1 particles bearing on their
surfaces large numbers of host-derived ICAM-1 proteins. Given that cellular
activation of leukocytes is known to modify the conformational state of LFA-1 and
induce ICAM-1 surface expression, it is tempting to speculate that activation of
virus-infected cells will lead to the production of HIV-1 particles bearing more
host ICAM-1 on their surfaces and that such progeny virions will preferentially
infect and replicate more efficiently in activated cells which are prevalent in
lymphoid organs.
PMID- 9765485
TI - Use of coreceptors other than CCR5 by non-syncytium-inducing adult and pediatric
isolates of human immunodeficiency virus type 1 is rare in vitro.
AB - We have tested a panel of pediatric and adult human immunodeficiency virus type 1
(HIV-1) primary isolates for the ability to employ the following proteins as
coreceptors during viral entry: CCR1, CCR2b, CCR3, CCR4, CCR5, CCR8, CXCR4,
Bonzo, BOB, GPR1, V28, US28, and APJ. Most non-syncytium-inducing isolates could
utilize only CCR5. All syncytium-inducing viruses used CXCR4, some also employed
V28, and one (DH123) used CCR8 and APJ as well. A longitudinal series of HIV-1
subtype B isolates from an infected infant and its mother utilized Bonzo
efficiently, as well as CCR5. The maternal isolates, which were syncytium
inducing, also used CXCR4, CCR8, V28, and APJ.
PMID- 9765486
TI - CD4(+) T-lymphocyte depletion in human lymphoid tissue ex vivo is not induced by
noninfectious human immunodeficiency virus type 1 virions.
AB - We tested infectious human immunodeficiency virus type 1 (HIV-1), noninfectious
but conformationally authentic inactivated whole HIV-1 virions, and purified
gp120 for the ability to induce depletion of CD4(+) T cells in human lymphoid
tissues ex vivo. Infectious CXCR4-tropic HIV-1, but not matched inactivated
virions or gp120, mediated CD4(+) T-cell depletion, consistent with mechanisms
requiring productive infection.
PMID- 9765487
TI - Attachment and growth of human rotaviruses RV-3 and S12/85 in Caco-2 cells depend
on VP4.
AB - Studies with human neonatal rotaviruses RV-3 and S12/85 and their reassortants
showed that VP4 is a determinant of rotavirus attachment to and growth in Caco-2
cells. The binding of these viruses to MA104 and Caco-2 cells correlated with
their growth ability. Virus sensitivity to trypsin and the VP4 fusion region may
be implicated in these processes.
PMID- 9765488
TI - Roles of the human immunodeficiency virus type 1 nucleocapsid protein in
annealing and initiation versus elongation in reverse transcription of viral
negative-strand strong-stop DNA.
AB - To study the initiation of human immunodeficiency virus type 1 reverse
transcription, we have used the viral nucleocapsid protein (NC7) to anneal
tRNA3Lys primer onto viral genomic RNA and have then eliminated NC7 from this
primer-template complex by digestion with proteinase K and phenol-chloroform
extraction of residual protein. Our data show that saturating concentrations of
NC7 resulted in the formation of an active tRNA-template complex that yielded
enhanced production of full-length negative-strand strong-stop DNA [(-)ssDNA] and
that this complex remained active even after the elimination of NC7. While both
of the two Zn finger motifs found within NC7 were essential for efficient
elongation, NC protein that contained a point mutation in the first Zn finger or
that was devoid of both Zn fingers yielded primer-template complexes that could
still be initiated in 1-base-extension assays. In contrast, the use of heat
annealing to produce primer-template complexes resulted in proportions of full
length (-)ssDNA lower than those seen with NC protein, and the addition of NC
protein to such preformed primer-template complexes was able to reverse this
defect only to a marginal extent.
PMID- 9765489
TI - Metabolic labeling of woodchuck hepatitis B virus X protein in naturally infected
hepatocytes reveals a bimodal half-life and association with the nuclear
framework.
AB - In order to identify potential sites of hepadnavirus X protein action, we have
investigated the subcellular distribution and the stability of woodchuck
hepatitis virus (WHV) X protein (WHx) in primary hepatocytes isolated from
woodchucks with persistent WHV infection. In vivo cell labeling and cell
fractionation studies showed that the majority of WHx is a soluble cytoplasmic
protein while a minor part of newly synthesized WHx is associated with a nuclear
framework fraction (20%) and with cytoskeletal components (5 to 10%). Pulse-chase
experiments revealed that cytoplasmic WHx has a short half-life and decays with
bimodal kinetics (approximately 20 min and 3 h). The rates of association and
turnover of nucleus-associated WHx suggest that compartmentalization may be
responsible for the bimodal turnover observed in the cytoplasm.
PMID- 9765491
TI - The P2 protein of rice dwarf phytoreovirus is required for adsorption of the
virus to cells of the insect vector.
AB - Intact particles of rice dwarf phytoreovirus adsorbed to and entered monolayer
cultured cells of the insect vector Nephotettix cincticeps and multiplied within
the cells. Particles that lacked the P2 protein neither attached to nor infected
such cells. Furthermore, P2-free particles obtained from a transmission-competent
isolate of the virus were unable to infect insect vectors that had been allowed
to feed on these virus particles through a membrane. However, when such virus
particles were injected into insects via a glass capillary tube they successfully
infected the insects, which became able to transmit the virus. These results
support the hypothesis that, while P2-free particles can neither interact with
nor infect cells in the intestinal tract of the insect vector, they do retain the
ability to infect such cells when physically introduced into the hemolymph by
injection.
PMID- 9765490
TI - Identification and characterization of an RNA-dependent RNA polymerase activity
within the nonstructural protein 5B region of bovine viral diarrhea virus.
AB - Nonstructural protein 5B (NS5B) of bovine viral diarrhea virus (BVDV) contains
sequence motifs that are predictive of an RNA-dependent RNA polymerase activity.
We describe the expression and purification of the BVDV NS5B protein derived from
an infectious cDNA clone of BVDV (NADL strain). BVDV NS5B protein was active in
an in vitro RNA polymerase assay using homopolymeric RNA or BVDV minigenomic RNA
templates. The major product was a covalently linked double-stranded molecule
generated by a "copy-back" mechanism from the input template RNA. In addition, a
nucleotide-nonspecific and template-independent terminal nucleotidyl transferase
activity was observed with the BVDV NS5B preparation.
PMID- 9765492
TI - RNA-binding activity of the E1B 55-kilodalton protein from human adenovirus type
5.
AB - The human adenovirus 5 E1B 55-kDa protein is required for efficient
nucleocytoplasmic transport of late viral mRNAs. This protein is shown to have
RNA-binding activity which maps to a region of the protein with homology to a
family of RNA-binding proteins and which has been shown previously to be
essential for functionality of the protein in vivo.
PMID- 9765493
TI - Short consensus repeat domain 1 of decay-accelerating factor is required for
enterovirus 70 binding.
AB - Enterovirus 70 (EV70), like several other human enteroviruses, can utilize decay
accelerating factor (DAF [CD55]) as an attachment protein. Using chimeric
molecules composed of different combinations of the short consensus repeat
domains (SCRs) of DAF and membrane cofactor protein (CD46), we show that
sequences in SCR1 of DAF are essential for EV70 binding. Of the human
enteroviruses that can bind to DAF, only EV70 and coxsackievirus A21 require
sequences in SCR1 for this interaction.
PMID- 9765495
TI - His1, an archaeal virus of the Fuselloviridae family that infects Haloarcula
hispanica.
AB - A novel archaeal virus, His1, was isolated from hypersaline waters in
southeastern Australia. It was lytic, grew only on Haloarcula hispanica (titers
of up to 10(11) PFU/ml), and displayed a lemon-shaped morphology (74 by 44 nm)
previously reported only for a virus of the extreme thermophiles (SSV1). The
density of His1 was approximately 1.28 g/ml, similar to that of SSV1 (1.24 g/ml).
Purified particles were resistant to low salt concentrations. The genome was
linear, double-stranded DNA of 14.9 kb, similar to the genome of SSV1 (15.5 kb).
Morphologically, this isolate clearly belongs to the recently proposed
Fuselloviridae family of archaeal viruses. It is the first member of this family
from the extremely halophilic archaea, and its host, H. hispanica, can be readily
manipulated genetically.
PMID- 9765494
TI - Mapping of epitopes exposed on intact human immunodeficiency virus type 1 (HIV-1)
virions: a new strategy for studying the immunologic relatedness of HIV-1.
AB - To study the antigenic conservation of epitopes of human immunodeficiency virus
type 1 (HIV-1) isolates of different clades, the abilities of human anti-HIV-1
gp120 and gp41 monoclonal antibodies (MAbs) to bind to intact HIV-1 virions were
determined by a newly developed virus-binding assay. Eighteen human anti-HIV
MAbs, which were directed at the V2, V3 loop, CD4-binding domain (CD4bd), C5, or
gp41 regions, were used. Nine HIV-1 isolates from clades A, B, D, F, G, and H
were used. Microtiter wells were coated with the MAbs, after which virus was
added. Bound virus was detected after lysis by testing for p24 antigen with a
noncommercial p24 enzyme-linked immunosorbent assay. The anti-V3 MAbs strongly
bound the four clade B viruses and viruses from the non-B clades, although
binding was weaker and more sporadic with the latter. The degrees of binding by
the anti-V3 MAbs to CXCR4- and CCR5-tropic viruses were similar, suggesting that
the V3 loops of these two categories of viruses are similarly exposed. The anti
C5 MAbs bound isolates of clades A, B, and D. Only weak and sporadic binding of
all the viruses tested with anti-CD4bd, anti-V2, and anti-gp41 MAbs was detected.
These results suggest that V3 and C5 structures are shared and well exposed on
intact virions of different clades compared to the CD4bd, V2, and gp41 regions.
PMID- 9765497
TI - Requirement for CD4(+) T cells in the Friend murine retrovirus neutralizing
antibody response: evidence for functional T cells in genetic low-recovery mice.
AB - Recovery from infection with the Friend murine leukemia retrovirus complex (FV)
requires T-helper cells and cytotoxic T cells as well as neutralizing antibodies.
Several host genes, including genes of the major histocompatibility complex (H-2)
and an H-2-unlinked gene, Rfv-3, influence these FV-specific immune responses.
(B10.A x A/Wy)F1 mice, which have the H-2(a/a) Rfv-3(r/s) genotype, fail to mount
a detectable FV-specific T-cell proliferative response but nevertheless produce
FV-specific neutralizing immunoglobulin M (IgM) antibodies and can eliminate FV
viremia. Thus, this IgM response, primarily influenced by the Rfv-3 gene, may be
T-cell independent. To test this idea, mice were depleted of either CD4(+) or
CD8(+) T-cell populations in vivo and were monitored for the effect on the
neutralizing antibody response following FV infection. Surprisingly, mice in
which CD4(+) cells were depleted showed undetectable FV-neutralizing antibody
responses and high viremia levels compared to nondepleted or CD8-depleted
animals. In addition to knocking out the FV antibody response, CD4(+) T-cell
depletion reduced survival time significantly, further indicating the importance
of CD4(+) T cells. These studies revealed the first evidence for a functional T
cell response following FV infection in these low-recovery mice and showed that
CD4(+) T-helper cells are required for the Rfv-3-controlled FV antibody response.
PMID- 9765496
TI - The human T-cell leukemia virus type 1 oncoprotein Tax inhibits the
transcriptional activity of c-Myb through competition for the CREB binding
protein.
AB - Tax, the transforming protein of human T-cell leukemia virus type 1 (HTLV-1), is
required for strong activation of HTLV-1 transcription. This activation is
mediated through interaction with the KIX domain of the cellular coactivator CREB
binding protein (CBP). In this study we examined the possibility that the Tax-KIX
interaction may mediate effects on cellular gene transcription in vivo, as a
growing number of cellular transcription factors have been shown to utilize CBP
as a coactivator. We tested the ability of Tax to deregulate the activity of the
cellular transcription factor, c-Myb, since both Tax and c-Myb interact with the
KIX domain of CBP. Our results show that in vivo, Tax antagonizes the
transcriptional activity of c-Myb and, reciprocally, c-Myb antagonizes the
transcriptional activity of Tax. Furthermore, c-Myb competes for KIX binding to
Tax in vitro, indicating that these two transcription factors bind CBP in a
mutually exclusive manner. This novel mechanism of transcriptional interference
by Tax may promote globally deregulated cellular gene expression in the HTLV-1
infected cell, possibly leading to leukemogenesis.
PMID- 9765498
TI - Definition of amino acid residues on the epitope responsible for recognition by
influenza A virus H1-specific, H2-specific, and H1- and H2-cross-reactive murine
cytotoxic T-lymphocyte clones.
AB - We defined the epitopes recognized by three influenza A virus-specific, H-2Kd
restricted CD8(+) cytotoxic T-lymphocyte (CTL) clones: H1-specific clone A-12, H2
specific clone F-4, and H1- and H2-cross-reactive clone B7-B7. The A-12 and B7-B7
clones recognized the same peptide, which comprises amino acids 533 to 541
(IYSTVASSL) of A/PR/8 hemagglutinin (HA). The F-4 and B7-B7 clones both
recognized the peptide which comprise amino acids 529 to 537 (IYATVAGSL) of A/Jap
HA. Amino acids 533 to 541 of A/PR/8 HA are compatible with amino acids 529 to
537 of A/Jap HA. Amino acid S at positions 3 and 7 was responsible for
recognition by H1-specific clone A-12, while amino acid G at position 7 was
responsible for recognition by H2-specific clone F-4. Two conserved amino acids,
T at position 4 and A at position 6, were responsible for recognition by H1-, and
H2-cross-reactive clone B7-B7. These results indicate that a single nine-amino
acid region is recognized by HA-specific CTL clones of three different subtype
specificities and that the amino acids responsible for the recognition by the CTL
clones are different.
PMID- 9765499
TI - Viral cell entry induced by cross-linked decay-accelerating factor.
AB - Decay-accelerating factor (DAF) mediates cellular attachment for many human
picornaviruses. In most cases, viral binding to DAF is itself insufficient to
permit cell infectivity, with a second, functional internalization receptor being
required to facilitate this process. Previously, we postulated that the role of
DAF in enterovirus cell infection is as a sequestration receptor, maintaining a
reservoir of bound virus in an infectious state, awaiting interaction with
functional internalization receptors. Many of these functional receptors possess
the capacity to induce relatively rapid changes in capsid conformations,
resulting in the formation of altered particles (A-type particles). In this
report, we show that antibody-cross-linked DAF, in contrast to endogenous surface
expressed forms, can act as a functional virus receptor to mediate coxsackie A21
virus (CAV21) lytic cell infection. In contrast to the situation with ICAM-1
mediated CAV21 infection, in which high levels of A-type particles are formed,
cross-linked DAF-induced CAV21 replication occurs in the absence of detectable A
particle formation.
PMID- 9765500
TI - Mapping the prion protein using recombinant antibodies.
AB - The fundamental event in prion disease is thought to be the posttranslational
conversion of the cellular prion protein (PrPC) into a pathogenic isoform
(PrPSc). The occurrence of PrPC on the cell surface and PrPSc in amyloid plaques
in situ or in aggregates following purification complicates the study of the
molecular events that underlie the disease process. Monoclonal antibodies are
highly sensitive probes of protein conformation which can be used under these
conditions. Here, we report the rescue of a diverse panel of 19 PrP-specific
recombinant monoclonal antibodies from phage display libraries prepared from PrP
deficient (Prnp0/0) mice immunized with infectious prions either in the form of
rods or PrP 27-30 dispersed into liposomes. The antibodies recognize a number of
distinct linear and discontinuous epitopes that are presented to a varying degree
on different PrP preparations. The epitope reactivity of the recombinant PrP(90
231) molecule was almost indistinguishable from that of PrPC on the cell surface,
validating the importance of detailed structural studies on the recombinant
molecule. Only one epitope region at the C terminus of PrP was well presented on
both PrPC and PrPSc, while epitopes associated with most of the antibodies in the
panel were present on PrPC but absent from PrPSc.
PMID- 9765501
TI - The Caenorhabditis elegans gene T23G5.5 encodes an antidepressant- and cocaine
sensitive dopamine transporter.
AB - A small subset of neurons in the nematode Caenorhabditis elegans utilizes the
catecholamine dopamine (DA) as a neurotransmitter to control or modulate movement
and egg-laying. Disruption of DA-mediated behaviors represents a potentially
powerful strategy to identify genes that are likely to participate in
dopaminergic systems in man. In vertebrates, extracellular DA is inactivated by
presynaptic DA transport proteins (DATs) that are also major targets of addictive
agents, including amphetamines and cocaine. We used oligonucleotides derived from
the C. elegans genomic locus T23G5.5 to isolate and characterize T23G5.5 cDNAs.
Our studies predict that mRNAs from this locus encode a 615-amino-acid
polypeptide with twelve stretches of hydrophobicity suitable for transmembrane
domains, similar to that found in vertebrate catecholamine transporters. The
inferred translation product bears highest identity (43-47%) to catecholamine
(DA, norepinephrine, epinephrine) transporters within the GAT1/NET gene family
and possesses conserved residues implicated in amine substrate recognition.
Consistent with these findings, HeLa cells transfected with the C. elegans cDNA
exhibit saturable and high affinity DA transport (Km = 1.2 microM) that is
dependent on extracellular Na+ and Cl- and blocked by inhibitors of mammalian
catecholamine transporters, including norepinephrine transporter- and DAT
selective antagonists, tricyclic antidepressants, and the nonselective amine
transporter antagonists cocaine and D-amphetamine. These studies validate the
T23G5.5 locus as encoding a functional catecholamine transporter, providing
important comparative sequence information for catecholamine transporter
structure/function studies and a path to identify regulators of dopaminergic
signaling via genetic or pharmacologic manipulation of C. elegans cDNA in vivo.
PMID- 9765502
TI - Do specific or nonspecific interactions with proteins underlie inhalational
anesthetic action?
AB - To determine whether specific or nonspecific interactions between inhaled
anesthetics and proteins are more likely to underlie anesthetic actions, analysis
of hydrogen/tritium exchange was used to measure effects on the stability of two
model proteins that had been previously shown to bind anesthetics specifically
(bovine serum albumin) or only nonspecifically (myoglobin). The data indicated
that stabilization of albumin correlated with the potencies of a wide range of
anesthetic compounds significantly better than did destabilization of myoglobin.
In addition, sensitivity to nonanesthetics, isoflurane stereoselectivity, and
temperature and pressure effects all influenced the stabilization of bovine serum
albumin, but not the destabilization of myoglobin, in a manner strongly
supporting the premise that specific binding interactions with protein targets
underlie anesthetic action. These observations significantly increase the
likelihood that such interactions can be found and optimized.
PMID- 9765503
TI - Identification of a key amino acid of the beta2-adrenergic receptor for high
affinity binding of salmeterol.
AB - Transmembrane domains (TMDs) I, II, and VII of the beta2-adrenergic receptor
(beta2AR) were replaced, individually or in combination, with the corresponding
regions of the beta1AR, and vice versa. The beta2-selective binding of salmeterol
was not affected by the exchange of TMD I between the beta1- and beta2ARs. The
affinity of salmeterol was slightly decreased (32-fold) by replacement of TMD II
of the beta2AR with the homologous region of the beta1AR; the affinity was
strongly decreased (1870-fold) for the beta2AR with TMD VII of the beta1AR. The
affinity of salmeterol was partially restored by the introduction of TMD VII, but
not TMD II, of the beta2AR into the beta1AR. By analyzing alanine-substituted
mutants, we found that Tyr308 in TMD VII was mainly responsible for the high
affinity binding of salmeterol. Two salmeterol derivatives with the ether oxygen
at different positions in the side chain showed 33- and 64-fold decreased
affinities for the wild-type beta2AR, and a derivative with no ether oxygen
showed 147-fold decreased affinity for the wild-type beta2AR. These results
indicate that Tyr308 in TMD VII is the major amino acid conferring the beta2
selective binding of salmeterol to the beta2AR and that the position of the ether
oxygen in the side chain is also important for beta2-selective binding. A three
dimensional model of the salmeterol-beta2AR complex shows that the phenyl group
of Tyr308 interacts with methylene groups near the protonated amine of salmeterol
and the ether oxygen interacts with Tyr316.
PMID- 9765504
TI - Analysis of random recombination between human MDR1 and mouse mdr1a cDNA in a
pHaMDR-dihydrofolate reductase bicistronic expression system.
AB - Human P-glycoprotein (Pgp) confers multidrug resistance (MDR) to otherwise
sensitive cells. The homologous mouse Pgps, which are encoded by mouse mdr1a
(also known as mdr3) and mdr1b (also known as mdr1), confer different degrees of
resistance to the same MDR drugs and inhibitors. To create recombinants for the
study of sequences responsible for these differences in drug-resistance, chimeric
cDNA libraries can be constructed by homologous recombination of pools of related
sequences. This mutagenesis approach is called DNA shuffling. To select for
chimeric Pgp with an altered resistance profile, DNA shuffling between the
homologous but not identical drug interacting transmembrane domains 5 and 6 of
human MDR1 and mouse mdr1a was used. The chimeric proteins were expressed in
human KB-3-1 cells. One recombinant Pgp (clone 3-4) with a novel phenotype was
analyzed in detail. Inhibitors of Pgp, including verapamil and cyclosporin A,
were less effective in reversing resistance of the chimeric Pgp compared with
wild-type Pgp, for certain drugs. However, [125I]iodoarylazidoprazosin
photoaffinity labeling of the chimeric Pgp and its binding competition with
cyclosporin A, showed that cyclosporin A competed for the photoaffinity labeling.
The chimeric Pgp cells stained less well with human-specific anti-Pgp mAb MRK16
than wild-type Pgp, despite having the described epitopes for MRK16. Staining
with human-specific mAb UIC2 was increased when the chimeric protein was compared
with wild-type Pgp. These results suggest an alteration in exposure of human Pgp
specific epitopes in this chimeric Pgp, as well as a change in the interaction of
reversing agents with the chimeric protein.
PMID- 9765505
TI - Protein synthesis is required for caspase activation and induction of apoptosis
by bisphosphonate drugs.
AB - The exact mechanisms of action of antiresorptive bisphosphonate drugs remain
unclear, although they may inhibit bone resorption by mechanisms that can lead to
osteoclast apoptosis. These drugs also cause apoptosis in J774 macrophages,
probably as a consequence of inhibition of protein prenylation. However, the
molecular pathways that lead to apoptosis are not known. In some cells, apoptosis
induced by statins (other inhibitors of protein prenylation) is dependent on
protein synthesis. The aim of this study was to further characterize the kinetics
and biochemical features of bisphosphonate-induced apoptosis, including the
dependence on protein synthesis. Alendronate-induced apoptosis in J774 cells
occurred after approximately 16 hr of treatment, although shorter exposures to
the drug followed by incubation in bisphosphonate-free medium also committed
cells to apoptosis. The appearance of apoptotic cells was associated with the
appearance of caspase-3-like activity. Apoptosis induced by bisphosphonate or
mevastatin was found to be dependent on protein synthesis because cycloheximide
inhibited chromatin condensation, DNA fragmentation and activation of caspase-3
like protease or proteases. Protein synthesis was required for events that lead
to commitment to apoptosis but not for the execution phase because cycloheximide
did not prevent apoptosis when added >/=15 hr after the start of alendronate
treatment. Furthermore, staurosporine-induced caspase-3-like activity and
apoptosis in J774 cells could not be prevented by cycloheximide. These
observations demonstrate that activation of caspase-3-like proteases and
inhibition of commitment to apoptosis by cycloheximide are common features of
apoptotic cell death induced by inhibitors of protein prenylation such as
bisphosphonates.
PMID- 9765506
TI - Activation of glycine and glutamate receptors increases intracellular calcium in
cells derived from the endocrine pancreas.
AB - We studied calcium signaling in a newly described pancreatic cell line, GK-P3,
that expresses functional amino acid neurotransmitter receptors. GK-P3 cells
express the first strychnine-sensitive glycine receptors reported in a permanent
cell line. In addition, GK-P3 cells express alpha-amino-3-hydroxy-5-methyl-4
isoxazolepropionic acid (AMPA)-type glutamate receptors. Both types of amino acid
receptors showed electrophysiological and pharmacological behavior similar to
their neuronal counterparts. The glycine receptors were permeable to Cl- and
blocked by the selective antagonist strychnine. AMPA receptors showed limited
permeability to Ca2+, were blocked by 6-cyano-2, 3-dihydroxy-7-nitroquinoxaline,
and were potentiated by cyclothiazide. Interestingly, activation of either
receptor type increased intracellular Ca2+ measured by digital imaging of Fura-2
fluorescence. These Ca2+ signals were completely blocked by 30 microM La3+,
suggesting that the Ca2+ entered the cells largely through voltage-dependent Ca2+
channels. Alterations in the extracellular concentrations of Cl- and/or HCO3- had
only marginal effects on glycine-evoked Ca2+ signals. However, increases in
intracellular Ca2+ mediated by AMPA receptors were absent when the extracellular
Na+ was replaced with an impermeant cation, N-methyl-D-glucamine. We conclude
that activation of ligand-gated cation or anion channels depolarize GK-P3 cells
sufficiently to activate their voltage-gated Ca2+ channels leading to increases
in intracellular Ca2+ concentration. Thus, glycine and glutamate receptors may
regulate Ca2+-dependent secretory mechanisms in islet cells by altering the
membrane potential of these cells. Our data in GK-P3 cells support the growing
weight of evidence for a role of amino acid neurotransmitters in pancreatic
islets and introduce strychnine-sensitive glycine receptors as a novel target of
amino acid neurotransmitter regulation in islets.
PMID- 9765508
TI - Chronic morphine augments G(beta)(gamma)/Gs(alpha) stimulation of adenylyl
cyclase: relevance to opioid tolerance.
AB - In the current study, we investigated the neurochemical basis for the previously
reported predominance of stimulatory mu-opioid signaling in guinea pig
longitudinal muscle/myenteric plexus (LMMP) preparations after chronic in vivo
morphine exposure. As expected, recombinant Gsalpha (rGsalpha) dose-dependently
stimulated adenylyl cyclase (AC) activity in LMMP membranes obtained from opioid
naive as well as tolerant LMMP tissue. However, the magnitude of the increase was
significantly greater in the latter than in the former. The Gbetagamma blocking
peptide QEHA (50 microM) essentially abolished stimulation by rGsalpha in LMMP
membranes obtained from both opioid naive and tolerant animals. Interestingly,
after partial blockade by lower QEHA concentrations, the incremental AC
stimulation by rGsalpha in tolerant LMMP membranes was no longer observed,
indicating augmented Gbetagamma stimulatory responsiveness. Concomitant changes
in the content of AC isoform protein are consistent with these biochemical
observations. After chronic systemic morphine, AC protein is augmented
significantly (56%). This increment is most likely to be composed of AC isoforms
that are stimulated by Gbetagamma. This is the first demonstration in a complex
mammalian tissue that persistent activation of opioid receptors results in
augmented Gbetagamma/Gsalpha AC stimulatory interactiveness. The relevance of
such changes to the manifestation of opioid tolerance is discussed.
PMID- 9765507
TI - Polymorphic expression of the UDP-glucuronosyltransferase UGT1A gene locus in
human gastric epithelium.
AB - The human UDP-glucuronosyltransferase (UGT) 1A (UGT1A) locus is regulated in a
tissue specific fashion in liver and extrahepatic tissues. Three extrahepatic
UGT1A proteins, UGT1A7, UGT1A8, and UGT1A10, have been discovered and are
believed to contribute to the diversity of extrahepatic glucuronidation. UGTs
eliminate by glucuronidation a broad variety of endobiotic and xenobiotic
substrates, which include bilirubin, therapeutic drugs, and carcinogens. Human
gastric mucosa represents a primary location of tissue contact with dietary
constituents, pharmaceutical drugs, and environmental carcinogens. To study the
role and regulation of UGT1A gene products in stomach UGT1A mRNA expression and
UGT catalytic activities were investigated in a panel of 14 normal gastric
mucosa/adenocarcinoma sample pairs. UGT1A mRNA levels were differentially
regulated in stomach, a feature not found in hepatic tissue. Normal gastric
epithelium consistently expressed extrahepatic UGT1A7 and UGT1A10. However,
polymorphic expression of UGT1A1 (29%), UGT1A3 (21%), and UGT1A6 (36%) was
detected. Polymorphic UGT1A regulation was confirmed in adenocarcinoma samples
with the additional observation of differential down-regulation of UGT1A1,
UGT1A3, UGT1A6, and UGT1A10 and up-regulation of UGT1A7 mRNA. The polymorphic
UGT1A regulation in stomach contrasts the homogeneous regulation of UGT1A gene
products in human liver. Activity assays demonstrated 2- to 4-fold
interindividual differences in UGT activity and qualitative differences between
individuals. The polymorphic regulation of UGT1A gene products in gastric tissue
may be the biological basis that determines interindividual differences in
extrahepatic microsomal drug metabolism.
PMID- 9765509
TI - Modulation of apoptosis in rat thymocytes by analogs of staurosporine: lack of
direct association with inhibition of protein kinase C.
AB - Protein kinase C (PKC) is an important constituent of the signaling pathways
involved in apoptosis. The PKC inhibitor staurosporine induces apoptosis in many
cell types. We characterized the role of PKC in the induction of apoptosis in
immature rat thymocytes by investigating the effects of staurosporine with those
of five analogs. Four of them, the indolocarbazoles CGP 41251 and UCN-01 and the
bisindolylmaleimides RO 31-8220 and GF 109203X, possess high PKC-inhibitory
specificity and potency, whereas one, the UCN-01 stereoisomer UCN-02, is a weak
PKC inhibitor. Apoptosis was examined by flow cytometry, internucleosomal DNA
cleavage, and formation of large DNA fragments. Staurosporine, UCN-01, and UCN-02
induced a concentration- and time-dependent increase in apoptosis, whereas
neither CGP 41251, RO 31-8220, nor GF 109203X induced apoptosis. The mechanism of
induction of apoptosis by staurosporine, UCN-01, and UCN-02 was clearly different
from the mechanism that mediates induction of apoptosis by etoposide and
dexamethasone, as judged by differential effects of modulators of apoptosis.
Staurosporine, UCN-01, and UCN-02 at concentrations of a hundredth to a
thousandth of those at which they induced apoptosis, and RO 31-8220 inhibited
apoptosis elicited by thapsigargin but not apoptosis caused by dexamethasone or
etoposide. The results suggest that (i) UCN-01 and UCN-02 mimic staurosporine as
inducers of thymocyte apoptosis; (ii) staurosporine, UCN-01 and UCN-02 share a
biphasic effect on apoptosis in rat thymocytes, being inhibitory at low
concentrations and stimulatory at high concentrations; and (iii) inhibition of
PKC alone is insufficient for induction of apoptosis in thymocytes.
PMID- 9765510
TI - The aryl hydrocarbon receptor interacts with transcription factor IIB.
AB - The aryl hydrocarbon receptor (AHR) and its DNA binding partner, the AHR nuclear
translocator (ARNT), are basic helix-loop-helix transcription factors that
mediate many of the toxic and carcinogenic effects of polyhalogenated aromatic
hydrocarbons. The basic regions of the AHR and ARNT contact the GCGTG recognition
site, whereas both their helix-loop-helix domains and periodicity-ARNT-single
minded domains participate in heterodimerization. To delineate the transcription
factors that may facilitate DNA binding and transcriptional activation of the
AHR/ARNT heterodimer, we questioned whether transcription factor IIB (TFIIB) may
interact with either the AHR or ARNT and whether this interaction may affect the
ability of the AHR/ARNT complex to bind DNA. Coaffinity precipitation assays
demonstrated that both the AHR and ARNT were capable of interacting with TFIIB.
Domain mapping experiments revealed that TFIIB interacts with the periodicity
ARNT-single-minded and carboxyl-terminal regions of the AHR. To determine whether
the interaction between TFIIB and the AHR may affect DNA binding of the AHR and
ARNT complex, we performed gel shift experiments in the absence and presence of
TFIIB. The addition of TFIIB significantly increased the formation of the
AHR/ARNT DNA binding complex, but only if TFIIB was first allowed to interact
with the AHR before the addition of ARNT. These results indicate that TFIIB
interacts with the AHR and may stabilize the DNA binding form of the AHR and
thereby augment the ability of the AHR/ARNT complex to interact with its DNA
recognition site.
PMID- 9765511
TI - A synergistic neurotrophic response to l-dihydroxyphenylalanine and nerve growth
factor.
AB - The catecholamine precursor l-dihydroxyphenylalanine (L-DOPA) is the primary
therapeutic intervention for Parkinson's disease. Although short-term exposure
(30 min) potentiates dopamine (DA) release by elevating quantal size, longer term
exposure to L-DOPA (48 hr) promotes neurite outgrowth from midbrain DA neurons in
culture. To characterize long term effects of L-DOPA, we used a pheochromocytoma
(PC12) line that extends neurites on exposure to nerve growth factor (NGF). L
DOPA potentiated the outgrowth of processes elicited by NGF. This response did
not require conversion of L-DOPA to DA, was not caused by agonist effects at DA
receptors, and was not blocked by the tyrosine kinase inhibitor genistein.
However, similar results were found after exposure to l-n-acetylcysteine or
apomorphine, a DA receptor agonist that produces a quinone metabolite, and seemed
to correlate with glutathione synthesis. Long-term process elaboration was
blocked by L-buthionine sulfoximine, consistent with mediation by an antioxidant
mechanism. L-DOPA potentiation of NGF response was important functionally as seen
by increased quantal neurotransmitter release from the L-DOPA/NGF-treated neurite
varicosities, which displayed both 2-fold greater quantal size and frequency of
quantal release. These results demonstrate potentiation by L-DOPA of
morphological and physiological responses to neurotrophic factors as well as
synergistic induction of antioxidant pathways. Together with effects on
transmitter synthesis, these properties seem to provide a basis for the
compound's long term presynaptic potentiation of DA release and therapeutic
actions.
PMID- 9765512
TI - Molecular characterization of human and rat RGS 9L, a novel splice variant
enriched in dopamine target regions, and chromosomal localization of the RGS 9
gene.
AB - A novel splice variant of RGS 9 was isolated from a rat hypothalamus, human
retina, and a human kidney (Wilm's) tumor. This variant, termed RGS 9L, differs
from the retinal form (termed RGS 9S) identified previously in that it contains a
211- (rat) or 205- (human) amino acid proline-rich domain on the carboxyl
terminus. The pattern of RGS 9 mRNA splicing was tissue specific, with striatum,
hypothalamus- and nucleus accumbens expressing RGS 9L, whereas retina and pineal
expressed RGS 9S almost exclusively. This pattern of mRNA splicing seemed to be
highly conserved between human and rodents, suggesting cell-specific differences
in the function of these variants. Transient expression of RGS 9L augmented basal
and beta-adrenergic receptor-stimulated adenylyl cyclase activity while
suppressing dopamine D2 receptor-mediated inhibition. Furthermore, RGS 9L
expression greatly accelerated the decay of dopamine D2 receptor-induced GIRK
current. These results indicate RGS 9L inhibits heterotrimeric Gi function in
vivo, probably by acting as a GTPase-activating protein. The human RGS 9 gene was
localized to chromosome 17 q23-24 by radiation hybrid and fluorescent in situ
hybridization analyses. The RGS 9 gene is within a previously defined locus for
retinitis pigmentosa (RP 17), a disease that has been linked to genes in the
rhodopsin/transducin/cGMP signaling pathway.
PMID- 9765513
TI - HERG and KvLQT1/IsK, the cardiac K+ channels involved in long QT syndromes, are
targets for calcium channel blockers.
AB - We examined the effects of the calcium channel blockers nitrendipine, diltiazem,
verapamil, bepridil, and mibefradil on the cloned HERG and KvLQT1/IsK K+
channels. These channels generate the rapid and slow components of the cardiac
delayed rectifier K+ current, and mutations can affect them, which leads to long
QT syndromes. When expressed in transfected COS cells, HERG is blocked in a
concentration-dependent manner by bepridil (EC50 = 0.55 microM), verapamil (EC50
= 0.83 microM), and mibefradil (EC50 = 1.43 microM), whereas nitrendipine and
diltiazem have negligible effects. Steady state activation and inactivation
parameters are shifted to more negative values in the presence of the blockers.
Similarly, KvLQT1/IsK is inhibited by bepridil (EC50 = 10.0 microM) and
mibefradil (EC50 = 11.8 microM), while being insensitive to nitrendipine,
diltiazem, or verapamil. These results demonstrate that both cloned K+ channels
HERG and KvLQT1/IsK, which represent together the cardiac delayed rectifier K+
current, are sensitive targets to calcium channel blockers. This work may help in
understanding the mechanisms of action of verapamil in certain ventricular
tachycardia, as well as some of the deleterious adverse cardiac events associated
with bepridil.
PMID- 9765514
TI - Agonist induced homologous desensitization of mu-opioid receptors mediated by G
protein-coupled receptor kinases is dependent on agonist efficacy.
AB - Using Xenopus laevis oocytes coexpressing mammalian mu-opioid receptors (MORs),
beta-adrenergic receptor kinase 2 (beta-ARK2) [also called G protein-coupled
receptor kinase (GRK3)], and beta-arrestin 2 (beta-arr 2), we compared the rates
of beta-ARK2 (GRK3)- and beta-arr 2-mediated homologous receptor desensitization
produced by treatment with opioid agonists of different efficacies. The response
to MOR activation was measured using two-electrode voltage clamp as an increase
in the conductance of the coexpressed G protein-coupled inwardly rectifying
potassium (heteromultimer of KIR3.1 and KIR3.4) channels. Treatment with opioids
of high efficacy, either [D-Ala2,N-MePhe4,Gly-ol5]-enkephalin, fentanyl, or
sufentanyl, produced a GRK3- and beta-arr 2-dependent reduction in response in
<20 min, whereas treatment with the partial agonist morphine produced receptor
desensitization at a significantly slower rate. Because GRK3 requires activation
and membrane targeting by free G protein betagamma subunits released after
agonist-mediated activation of G proteins, a low efficacy agonist such as
morphine may produce weak receptor desensitization as a consequence of poor GRK3
activation. To address this hypothesis, we substituted GRK5, a GRK that does not
require activation by G protein betagamma. In oocytes expressing GRK5 instead of
GRK3, both [D-Ala2,N-MePhe4, Gly-ol5]enkephalin and fentanyl, but not morphine,
produced desensitization of MOR-activated potassium conductance. Thus, mu-opioid
agonists produced significant receptor desensitization, mediated by either GRK3
or GRK5, at a rate dependent on agonist efficacy.
PMID- 9765515
TI - A common anticonvulsant binding site for phenytoin, carbamazepine, and
lamotrigine in neuronal Na+ channels.
AB - Phenytoin, carbamazepine, and lamotrigine are anticonvulsants frequently
prescribed in seizure clinics. These drugs all show voltage-dependent inhibition
of Na+ currents, which has been implicated as the major mechanism underlying the
antiepileptic effect. In this study, I examine the inhibition of Na+ currents by
mixtures of different anticonvulsants. Quantitative analysis of the shift of
steady state inactivation curve in the presence of multiple drugs argues that one
channel can be occupied by only one drug molecule. Moreover, the recovery from
inhibition by a mixture of two drugs (a fast-unbinding drug plus a slow-unbinding
drug) is faster, or at least not slower, than the recovery from inhibition by the
slow-unbinding drug alone. Such kinetic characteristics further strengthen the
argument that binding of one anticonvulsant to the Na+ channel precludes binding
of the other. It also is found that these anticonvulsants are effective
inhibitors of Na+ currents only when applied externally, not internally.
Altogether these findings suggest that phenytoin, carbamazepine, and lamotrigine
bind to a common receptor located on the extracellular side of the Na+ channel.
Because these anticonvulsants all have much higher affinity to the inactivated
state than to the resting state of the Na+ channel, the anticonvulsant receptor
probably does not exist in the resting state. Thus, there may be correlative
conformational changes for the making of the receptor on the extracellular side
of the channel during the gating process.
PMID- 9765516
TI - Detachment of cytochrome c by cationic drugs from membranes containing acidic
phospholipids: comparison of lidocaine, propranolol, and gentamycin.
AB - A large number of pharmaceutically active compounds have a high affinity to
acidic phospholipids; good examples are the cationic compounds lidocaine,
propranolol, and gentamycin. These drugs influenced the lipid dynamics of
liposomes composed of phosphatidylcholine and the acidic phosphatidylglycerol, as
judged by the excimer/monomer emission intensity ratio for a pyrene-labeled
phospholipid analog, as well as by polarization of DPH fluorescence. When the
mole fraction X of PG (XPG) was 0.20, lidocaine increased membrane fluidity. The
opposite was true for propranolol, which caused the formation of pyrene lipid
enriched microdomains. Gentamycin had no apparent effect. At XPG = 1.00, all
these drugs rigidified membrane. Subsequently, we investigated the detachment of
a cationic peripheral membrane protein, cytochrome c (cyt c), by these compounds
from liposomes. This was accomplished by monitoring resonance energy transfer
from a pyrene-labeled phospholipid to the heme of cyt c. The efficiency of the
above compounds to dissociate cyt c varied considerably. In brief, significantly
lower concentrations of gentamycin than propranolol or lidocaine were required
for half-maximal dissociation of cyt c from liposomes, although the final extent
of protein detachment by gentamycin was less complete. ATP augmented the
dissociation of cyt c from membranes by lidocaine and propranolol. Stopped-flow
measurements also revealed that the half-times differed for the release of cyt c
from the membranes. Our results are likely to reflect differences in the
contributions of the electrostatic interactions and hydrophobicity to the
drug/lipid interaction and comply with two different acidic phospholipid binding
sites in cyt c.
PMID- 9765517
TI - Lysine point mutations in Na+ channel D4-S6 reduce inactivated channel block by
local anesthetics.
AB - Voltage-gated Na+ channels are a primary target for local anesthetics (LAs). Open
or inactivated Na+ channels usually have a severalfold higher affinity for LAs
than do resting channels. Hille's modulated receptor hypothesis attributed the
changes in LA affinity to state-dependent alterations in the conformation of the
LA receptor. We expressed wild-type and mutant rat skeletal muscle (mu1) Na+
channels in human embryonic kidney cells to investigate the state-dependent
modulation of LA receptor affinity. As an alternative approach to using alanine
for point mutation, we substituted lysine (a hydrophilic residue) for native
residues in the putative LA receptor located in D4-S6 of the mu1 Na+ channel.
Lysine mutation at Y1586 did not alter resting channel affinity for cocaine but
did reduce resting affinity at F1579K and N1584K by 2- and 3-fold, respectively.
Compared with mu1, resting benzocaine block did not change at F1579K, decreased
at N1584K, and increased at Y1586K. These effects on resting block could largely
be accounted for by either steric/charge interference or cation-pi electron
interactions between particular moieties on the LA and lysine. Surprisingly,
lysine substitution at these residues allowed the channels to undergo steady
state fast inactivation yet reduced inactivated channel block by cocaine by up to
27-fold and reduced the benzocaine-induced leftward shift in the h(infinity)
curve by up to 22 mV. Our data suggest that transitions in channel state indeed
invoke conformational changes in the LA receptor and that lysine mutations in the
LA receptor region alter such conformational changes during the transition to the
inactivated state.
PMID- 9765519
TI - Cell wall loosening by expansins.
PMID- 9765518
TI - Regulation of rabbit cytochrome P450 2E1 expression in HepG2 cells by insulin and
thyroid hormone.
AB - The regulation of cytochrome P450 (CYP) 2E1, the ethanol-inducible isoform, is
particularly complex. The level is affected by a variety of other foreign
compounds, by insulin (as studied in several laboratories), and by
triiodothyronine (T3), which has not been previously examined at the molecular
level. In the present investigation, a stably transfected HepG2 cell line
harboring a rabbit CYP2E1 minigene containing the coding sequence together with
1.6 kilobases of the 5' flanking region and the untranslated region (UTR), as
well as 0.5 kilobases of the 3' UTR, was established. Western blot analysis
showed that 1 microM insulin decreased the CYP2E1 protein level in a dose- and
time-dependent manner, whereas 1 microM T3 increased the level 2-fold in 1 day
and 8-fold in 5 days. Similarly, steady state CYP2E1 mRNA levels were decreased
by insulin but were increased by T3. Neither hormone affected the transcription
rate of the CYP2E1 5' flanking region with an UTR/luciferase fusion gene,
indicating that the regulation is post-transcriptional in this system under our
experimental conditions. When the CYP2E1 3' UTR was removed from the minigene,
CYP2E1 mRNA and protein were up-regulated by insulin but were not affected by T3.
These findings, including mRNA half-life determinations, indicate that the
effects of insulin and T3 are a result of altered mRNA stability and that the 3'
UTR of CYP2E1 contains regulatory information for these hormone-mediated effects.
PMID- 9765520
TI - How does auxin turn on genes?
PMID- 9765521
TI - Shifts of intracellular pH distribution as a part of the signal mechanism leading
to the elicitation of benzophenanthridine alkaloids . Phytoalexin biosynthesis in
cultured cells of eschscholtzia californica
AB - Cultured cells of Eschscholtzia californica (Californian poppy) respond to a
yeast elicitor preparation or Penicillium cyclopium spores with the production of
benzophenanthridine alkaloids, which are potent phytoalexins. Confocal pH mapping
with the probe carboxy-seminaphthorhodafluor-1-acetoxymethylester revealed
characteristic shifts of the pH distribution in challenged cells: within a few
minutes after elicitor contact a transient acidification of cytoplasmic and
nuclear areas occurred in parallel with an increase of the vacuolar pH. The
change of proton concentration in the vacuole and in the extravacuolar area
showed a nearly constant relation, indicating an efflux of vacuolar protons into
the cytosol. A 10-min treatment with 2 mM butyric or pivalic acid caused a
transient acidification of the cytoplasm comparable to that observed after
elicitor contact and also induced alkaloid biosynthesis. Experimental depletion
of the vacuolar proton pool reversibly prevented both the elicitor-triggered pH
shifts and the induction of alkaloid biosynthesis. pH shifts and induction of
alkaloid biosynthesis showed a similar dependence on the elicitor concentration.
Net efflux of K+, alkalinization of the outer medium, and browning of the cells
were evoked only at higher elicitor concentrations. We suggest that transient
acidification of the cytoplasm via efflux of vacuolar protons is both a necessary
and sufficient step in the signal path toward biosynthesis of benzophenanthridine
alkaloids in Californian poppy cells.
PMID- 9765522
TI - Eucalypt MADS-box genes expressed in developing flowers.
AB - Three MADS-box genes were identified from a cDNA library derived from young
flowers of Eucalyptus grandis W. Hill ex Maiden. The three egm genes are single
copy genes and are expressed almost exclusively in flowers. The egm1 and egm3
genes shared strongest homology with other plant MADS-box genes, which mediate
between the floral meristem and the organ-identity genes. The egm3 gene was also
expressed strongly in the receptacle or floral tube, which surrounds the carpels
in the eucalypt flower and bears the sepals, petals, and numerous stamens. There
appeared to be a group of genes in eucalypts with strong homology with the 3'
region of the egm1 gene. The egm2 gene was expressed in eucalypt petals and
stamens and was most homologous to MADS-box genes, which belong to the globosa
group of genes, which regulate organogenesis of the second and third floral
whorls. The possible role of these three genes in eucalypt floral development is
discussed.
PMID- 9765523
TI - Developmental regulation of intercellular protein trafficking through
plasmodesmata in tobacco leaf epidermis
AB - Plasmodesmata mediate direct cell-to-cell communication in plants. One of their
significant features is that primary plasmodesmata formed at the time of
cytokinesis often undergo structural modifications, by the de novo addition of
cytoplasmic strands across cell walls, to become complex secondary plasmodesmata
during plant development. Whether such modifications allow plasmodesmata to gain
special transport functions has been an outstanding issue in plant biology. Here
we present data showing that the cucumber mosaic virus 3a movement protein
(MP):green fluorescent protein (GFP) fusion was not targeted to primary
plasmodesmata in the epidermis of young or mature leaves in transgenic tobacco
(Nicotiana tabacum) plants constitutively expressing the 3a:GFP fusion gene.
Furthermore, the cucumber mosaic virus 3a MP:GFP fusion protein produced in
planta by biolistic bombardment of the 3a:GFP fusion gene did not traffic between
cells interconnected by primary plasmodesmata in the epidermis of a young leaf.
In contrast, the 3a MP:GFP was targeted to complex secondary plasmodesmata and
trafficked from cell to cell when a leaf reached a certain developmental stage.
These data provide the first experimental evidence, to our knowledge, that
primary and complex secondary plasmodesmata have different protein-trafficking
functions and suggest that complex secondary plasmodesmata may be formed to
traffic specific macromolecules that are important for certain stages of leaf
development.
PMID- 9765524
TI - Metallothioneins 1 and 2 have distinct but overlapping expression patterns in
Arabidopsis.
AB - The spatial and temporal expression patterns of metallothionein (MT) isoforms
MT1a and MT2a were investigated in vegetative and reproductive tissues of
untreated and copper-treated Arabidopsis by in situ hybridization and by northern
blotting. In control plants, MT1a mRNA was localized in leaf trichomes and in the
vascular tissue in leaves, roots, flowers, and germinating embryos. In copper
treated plants, MT1a expression was also observed in the leaf mesophyll and in
vascular tissue of developing siliques and seeds. In contrast, MT2a was expressed
primarily in the trichomes of both untreated and copper-treated plants. In copper
treated plants, MT2a mRNA was also expressed in siliques. Northern-hybridization
studies performed on developing seedlings and leaves showed temporal variations
of MT1a gene expression but not of MT2a expression. The possible implications of
these findings for the cellular roles of MTs in plants are discussed.
PMID- 9765525
TI - A fiberless seed mutation in cotton is associated with lack of fiber cell
initiation in ovule epidermis and alterations in sucrose synthase expression and
carbon partitioning in developing seeds
AB - Fiber cell initiation in the epidermal cells of cotton (Gossypium hirsutum L.)
ovules represents a unique example of trichome development in higher plants.
Little is known about the molecular and metabolic mechanisms controlling this
process. Here we report a comparative analysis of a fiberless seed (fls) mutant
(lacking fibers) and a normal (FLS) mutant to better understand the initial
cytological events in fiber development and to analyze the metabolic changes that
are associated with the loss of a major sink for sucrose during cellulose
biosynthesis in the mutant seeds. On the day of anthesis (0 DAA), the mutant
ovular epidermal cells lacked the typical bud-like projections that are seen in
FLS ovules and are required for commitment to the fiber development pathway. Cell
specific gene expression analyses at 0 DAA showed that sucrose synthase (SuSy)
RNA and protein were undetectable in fls ovules but were in abundant, steady
state levels in initiating fiber cells of the FLS ovules. Tissue-level analyses
of developing seeds 15 to 35 DAA revealed an altered temporal pattern of SuSy
expression in the mutant relative to the normal genotype. Whether the altered
programming of SuSy expression is the cause or the result of the mutation is
unknown. The developing seeds of the fls mutant have also shown several
correlated changes that represent altered carbon partitioning in seed coats and
cotyledons as compared with the FLS genotype.
PMID- 9765526
TI - Arabidopsis Rho-related GTPases: differential gene expression in pollen and polar
localization in fission yeast.
AB - The Rho small GTP-binding proteins are versatile, conserved molecular switches in
eukaryotic signal transduction. Plants contain a unique subfamily of Rho-GTPases
called Rop (Rho-related GTPases from plants). Our previous studies involving
injection of antibodies indicated that the pea Rop GTPase Rop1Ps is critical for
pollen tube growth. In this study we show that overexpression of an apparent
Arabidopsis ortholog of Rop1Ps, Rop1At, induces isotropic cell growth in fission
yeast (Schizosaccharomyces pombe) and that green fluorescence protein-tagged
Rop1At displays polar localization to the site of growth in yeast. We found that
Rop1At and two other Arabidopsis Rops, Rop3At and Rop5At, are all expressed in
mature pollen. All three pollen Rops fall into the same subgroup as Rop1Ps and
diverge from those Rops that are not expressed in mature pollen, suggesting a
coupling of the structural conservation of Rop GTPases to their gene expression
in pollen. However, pollen-specific transcript accumulation for Rop1At is much
higher than that for Rop3At and Rop5At. Furthermore, Rop1At is specifically
expressed in anthers, whereas Rop3At and Rop5At are also expressed in vegetative
tissues. In transgenic plants containing the Rop1At promoter:GUS fusion gene, GUS
is specifically expressed in mature pollen and pollen tubes. We propose that
Rop1At may play a predominant role in the regulation of polarized cell growth in
pollen, whereas its close relatives Rop3At and Rop5At may be functionally
redundant to Rop1At in pollen.
PMID- 9765527
TI - Proteasome inhibitors prevent tracheary element differentiation in zinnia
mesophyll cell cultures
AB - To determine whether proteasome activity is required for tracheary element (TE)
differentiation, the proteasome inhibitors clasto-lactacystin beta-lactone and
carbobenzoxy-leucinyl-leucinyl-leucinal (LLL) were used in a zinnia (Zinnia
elegans) mesophyll cell culture system. The addition of proteasome inhibitors at
the time of culture initiation prevented differentiation otherwise detectable at
96 h. Inhibition of the proteasome at 48 h, after cellular commitment to
differentiation, did not alter the final percentage of TEs compared with
controls. However, proteasome inhibition at 48 h delayed the differentiation
process by approximately 24 h, as indicated by examination of both morphological
markers and the expression of putative autolytic proteases. These results
indicate that proteasome function is required both for induction of TE
differentiation and for progression of the TE program in committed cells.
Treatment at 48 h with LLL but not clasto-lactacystin beta-lactone resulted in
partial uncoupling of autolysis from differentiation. Results from gel analysis
of protease activity suggested that the observed incomplete autolysis was due to
the ability of LLL to inhibit TE cysteine proteases.
PMID- 9765528
TI - S-adenosyl-L-methionine:L-methionine S-methyltransferase from germinating barley.
Purification and localization.
AB - S-Adenosyl-L-methionine:L-methionine S-methyltransferase (MMT) catalyzes the
synthesis of S-methyl-L-methionine (SMM) from L-methionine and S-adenosyl-L
methionine. SMM content increases during barley (Hordeum vulgare L.) germination.
Elucidating the role of this compound is important from both a fundamental and a
technological standpoint, because SMM is the precursor of dimethylsulfide, a
biogenic source of atmospheric S and an undesired component in beer. We present a
simple purification scheme for the MMT from barley consisting of 10% to 25%
polyethylene glycol fractionation, anion-exchange chromatography on
diethylaminoethyl-Sepharose, and affinity chromatography on adenosine-agarose. A
final activity yield of 23% and a 2765-fold purification factor were obtained.
After digestion of the protein with protease, the amino acid sequence of a major
peptide was determined and used to produce a synthetic peptide. A polyclonal
antibody was raised against this synthetic peptide conjugated to activated
keyhole limpet hemocyanin. The antibody recognized the 115-kD denatured MMT
protein and native MMT. During barley germination, both the specific activity and
the amount of MMT protein increased. MMT-specific activity was found to be higher
in the root and shoot than in the endosperm. MMT could be localized by an
immunohistochemical approach in the shoot, scutellum, and aleurone cells but not
in the root or endosperm (including aleurone).
PMID- 9765529
TI - Photosynthetic and heterotrophic ferredoxin isoproteins are colocalized in fruit
plastids of tomato
AB - Fruit tissues of tomato (Lycopersicon esculentum Mill.) contain both
photosynthetic and heterotrophic ferredoxin (FdA and FdE, respectively)
isoproteins, irrespective of their photosynthetic competence, but we did not
previously determine whether these proteins were colocalized in the same
plastids. In isolated fruit chloroplasts and chromoplasts, both FdA and FdE were
detected by immunoblotting. Colocalization of FdA and FdE in the same plastids
was demonstrated using double-staining immunofluorescence microscopy. We also
found that FdA and FdE were colocalized in fruit chloroplasts and
chloroamyloplasts irrespective of sink status of the plastid. Immunoelectron
microscopy demonstrated that FdA and FdE were randomly distributed within the
plastid stroma. To investigate the significance of the heterotrophic Fd in fruit
plastids, Glucose 6-phosphate dehydrogenase (G6PDH) activity was measured in
isolated fruit and leaf plastids. Fruit chloroplasts and chromoplasts showed much
higher G6PDH activity than did leaf chloroplasts, suggesting that high G6PDH
activity is linked with FdE to maintain nonphotosynthetic production of reducing
power. This result suggested that, despite their morphological resemblance, fruit
chloroplasts are functionally different from their leaf counterparts.
PMID- 9765530
TI - Characterization of a granule-bound starch synthase isoform found in the pericarp
of wheat.
AB - Waxy wheat (Triticum aestivum L.) lacks the waxy protein, which is also known as
granule-bound starch synthase I (GBSSI). The starch granules of waxy wheat
endosperm and pollen do not contain amylose and therefore stain red-brown with
iodine. However, we observed that starch from pericarp tissue of waxy wheat
stained blue-black and contained amylose. Significantly higher starch synthase
activity was detected in pericarp starch granules than in endosperm starch
granules. A granule-bound protein that differed from GBSSI in molecular mass and
isoelectric point was detected in the pericarp starch granules but not in
granules from endosperm. This protein was designated GBSSII. The N-terminal amino
acid sequence of GBSSII, although not identical to wheat GBSSI, showed strong
homology to waxy proteins or GBSSIs of cereals and potato, and contained the
motif KTGGL, which is the putative substrate-binding site of GBSSI of plants and
of glycogen synthase of Escherichia coli. GBSSII cross-reacted specifically with
antisera raised against potato and maize GBSSI. This study indicates that GBSSI
and GBSSII are expressed in a tissue-specific manner in different organs, with
GBSSII having an important function in amylose synthesis in the pericarp.
PMID- 9765531
TI - Overexpression of an Arabidopsis cDNA encoding a sterol-C24(1)-methyltransferase
in tobacco modifies the ratio of 24-methyl cholesterol to sitosterol and is
associated with growth reduction.
AB - Higher plants synthesize 24-methyl sterols and 24-ethyl sterols in defined
proportions. As a first step in investigating the physiological function of this
balance, an Arabidopsis cDNA encoding an S-adenosyl-L-methionine 24-methylene
lophenol-C24(1)-methyltransferase, the typical plant enzyme responsible for the
production of 24-ethyl sterols, was expressed in tobacco (Nicotiana tabacum L.)
under the control of a constitutive promoter. Transgenic plants displayed a novel
24-alkyl-Delta5-sterol profile: the ratio of 24-methyl cholesterol to sitosterol,
which is close to 1 in the wild type, decreased dramatically to values ranging
from 0.01 to 0.31. In succeeding generations of transgenic tobacco, a high S
adenosyl-L-methionine 24-methylene lophenol-C24(1)-methyltransferase enzyme
activity and, consequently, a low ratio of 24-methyl cholesterol to sitosterol,
was associated with reduced growth compared with the wild type. However, this new
morphological phenotype appeared only below the threshold ratio of 24-methyl
cholesterol to sitosterol of approximately 0.1. Because the size of cells was
unchanged in small, transgenic plants, we hypothesize that a radical decrease of
24-methyl cholesterol and/or a concomitant increase of sitosterol would be
responsible for a change in cell division through as-yet unknown mechanisms.
PMID- 9765532
TI - Manipulation of glutathione and amino acid biosynthesis in the chloroplast
AB - Poplars (Populus tremula x Populus alba) were transformed to overexpress
Escherichia coli gamma-glutamylcysteine synthetase (gamma-ECS) or glutathione
synthetase in the chloroplast. Five independent lines of each transformant
strongly expressed the introduced gene and possessed markedly enhanced activity
of the gene product. Glutathione (GSH) contents were unaffected by high
chloroplastic glutathione synthetase activity. Enhanced chloroplastic gamma-ECS
activity markedly increased gamma-glutamylcysteine and GSH levels. These effects
are similar to those previously observed in poplars overexpressing these enzymes
in the cytosol. Similar to cytosolic gamma-ECS overexpression, chloroplastic
overexpression did not deplete foliar cysteine or methionine pools and did not
lead to morphological changes. Light was required for maximal accumulation of GSH
in poplars overexpressing gamma-ECS in the chloroplast. High chloroplastic, but
not cytosolic, gamma-ECS activities were accompanied by increases in amino acids
synthesized in the chloroplast. We conclude that (a) GSH synthesis can occur in
the chloroplast and the cytosol and may be up-regulated in both compartments by
increased gamma-ECS activity, (b) interactions between GSH synthesis and the
pathways supplying the necessary substrates are similar in both compartments, and
(c) chloroplastic up-regulation of GSH synthesis is associated with an activating
effect on the synthesis of specific amino acids formed in the chloroplast.
PMID- 9765534
TI - Light and excess manganese . Implications for oxidative stress in common bean
AB - The effect of light intensity on antioxidants, antioxidant enzymes, and
chlorophyll content was studied in common bean (Phaseolus vulgaris L.) exposed to
excess Mn. Leaves of bean genotypes contrasting in Mn tolerance were exposed to
two different light intensities and to excess Mn; light was controlled by shading
a leaflet with filter paper. After 5 d of Mn treatment ascorbate was depleted by
45% in leaves of the Mn-sensitive genotype ZPV-292 and by 20% in the Mn-tolerant
genotype CALIMA. Nonprotein sulfhydryl groups and glutathione reductase were not
affected by Mn or light treatment. Ten days of Mn-toxicity stress increased leaf
ascorbate peroxidase activity of cv ZPV-292 by 78% in low light and by 235% in
high light, and superoxide dismutase activity followed a similar trend. Increases
of ascorbate peroxidase and superoxide dismutase activity observed in cv CALIMA
were lower than those observed in the susceptible cv ZPV-292. The cv CALIMA had
less ascorbate oxidation under excess Mn-toxicity stress. Depletion of ascorbate
occurred before the onset of chlorosis in Mn-stressed plants, especially in cv
ZPV-292. Lipid peroxidation was not detected in floating leaf discs of mature
leaves exposed to excess Mn. Our results suggest that Mn toxicity may be mediated
by oxidative stress, and that the tolerant genotype may maintain higher ascorbate
levels under stress than the sensitive genotype.
PMID- 9765533
TI - Inhibition of the gravitropic response of snapdragon spikes by the calcium
channel blocker lanthanum chloride.
AB - The putative Ca(2+)-channel blocker LaCl3 prevented the gravitropic bending of
cut snapdragon (Antirrhinum majus L.) spikes (S. Philosoph-Hadas, S. Meir, I.
Rosenberger, A.H. Halevy [1996] Plant Physiol 110: 301-310) and inhibited stem
curvature to a greater extent than vertical and horizontal stem elongation at the
bending zone. This might indicate that LaCl3, which modulates cytosolic Ca2+,
does not influence general stem-growth processes but may specifically affect
other gravity-associated processes occurring at the stem-bending zone. Two such
specific gravity-dependent events were found to occur in the bending zone of
snapdragon spikes: sedimentation of starch-containing chloroplasts at the bottom
of stem cortex cells, as seen in cross-sections, and establishment of an ethylene
gradient across the stem. Our results show that the lateral sedimentation of
chloroplasts associated with gravity sensing was prevented in cross-sections
taken from the bending zone of LaCl3-treated and subsequently gravistimulated
spikes and that LaCl3 completely prevented the gravity-induced, asymmetric
ethylene production established across the stem-bending zone. These data indicate
that LaCl3 inhibits stem curvature of snapdragon spikes by preventing several
gravity-dependent processes. Therefore, we propose that the gravitropic response
of shoots could be mediated through a Ca(2+)-dependent pathway involving
modulation of cytosolic Ca2+ at various stages.
PMID- 9765535
TI - Computation of surface electrical potentials of plant cell membranes .
Correspondence To published zeta potentials from diverse plant sources
AB - A Gouy-Chapman-Stern model has been developed for the computation of surface
electrical potential (psi0) of plant cell membranes in response to ionic solutes.
The present model is a modification of an earlier version developed to compute
the sorption of ions by wheat (Triticum aestivum L. cv Scout 66) root plasma
membranes. A single set of model parameters generates values for psi0 that
correlate highly with published zeta potentials of protoplasts and plasma
membrane vesicles from diverse plant sources. The model assumes ion binding to a
negatively charged site (R- = 0.3074 &mgr;mol m-2) and to a neutral site (P0 =
2.4 &mgr;mol m-2) according to the reactions R- + IZ &rlharr; RIZ-1 and P0 + IZ
&rlharr; PIZ, where IZ represents an ion of charge Z. Binding constants for the
negative site are 21, 500 M-1 for H+, 20,000 M-1 for Al3+, 2,200 M-1 for La3+, 30
M-1 for Ca2+ and Mg2+, and 1 M-1 for Na+ and K+. Binding constants for the
neutral site are 1/180 the value for binding to the negative site. Ion activities
at the membrane surface, computed on the basis of psi0, appear to determine many
aspects of plant-mineral interactions, including mineral nutrition and the
induction and alleviation of mineral toxicities, according to previous and
ongoing studies. A computer program with instructions for the computation of
psi0, ion binding, ion concentrations, and ion activities at membrane surfaces
may be requested from the authors.
PMID- 9765536
TI - Three mechanisms for the calcium alleviation of mineral toxicities
AB - Ca2+ in rooting medium is essential for root elongation, even in the absence of
added toxicants. In the presence of rhizotoxic levels of Al3+, H+, or Na+ (or
other cationic toxicants), supplementation of the medium with higher levels of
Ca2+ alleviates growth inhibition. Experiments to determine the mechanisms of
alleviation entailed measurements of root elongation in wheat (Triticum aestivum
L. cv Scout 66) seedlings in controlled medium. A Gouy-Chapman-Stern model was
used to compute the electrical potentials and the activities of ions at the root
cell plasma membrane surfaces. Analysis of root elongation relative to the
computed surface activities of ions revealed three separate mechanisms of Ca2+
alleviation. Mechanism I is the displacement of cell-surface toxicant by the Ca2+
induced reduction in cell-surface negativity. Mechanism II is the restoration of
Ca2+ at the cell surface if the surface Ca2+ has been reduced by the toxicant to
growth-limiting levels. Mechanism III is the collective ameliorative effect of
Ca2+ beyond mechanisms I and II, and may involve Ca2+-toxicant interactions at
the cell surface other than the displacement interactions of mechanisms I and II.
Mechanism I operated in the alleviation of all of the tested toxicities;
mechanism II was generally a minor component of alleviation; and mechanism III
was toxicant specific and operated strongly in the alleviation of Na+ toxicity,
moderately in the alleviation of H+ toxicity, and not at all in the alleviation
of Al3+ toxicity.
PMID- 9765537
TI - Changes in growth CO2 result in rapid adjustments of ribulose-1, 5-bisphosphate
Carboxylase/Oxygenase small subunit gene expression in expanding and mature
leaves of rice
AB - The accumulation of soluble carbohydrates resulting from growth under elevated
CO2 may potentially signal the repression of gene activity for the small subunit
of ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcS). To test this
hypothesis we grew rice (Oryza sativa L.) under ambient (350 &mgr;L L-1) and high
(700 &mgr;L L-1) CO2 in outdoor, sunlit, environment-controlled chambers and
performed a cross-switching of growth CO2 concentration at the late-vegetative
phase. Within 24 h, plants switched to high CO2 showed a 15% and 23% decrease in
rbcS mRNA, whereas plants switched to ambient CO2 increased 27% and 11% in
expanding and mature leaves, respectively. Ribulose-1,5-bisphosphate
carboxylase/oxygenase total activity and protein content 8 d after the switch
increased up to 27% and 20%, respectively, in plants switched to ambient CO2, but
changed very little in plants switched to high CO2. Plants maintained at high CO2
showed greater carbohydrate pool sizes and lower rbcS transcript levels than
plants kept at ambient CO2. However, after switching growth CO2 concentration,
there was not a simple correlation between carbohydrate and rbcS transcript
levels. We conclude that although carbohydrates may be important in the
regulation of rbcS expression, changes in total pool size alone could not predict
the rapid changes in expression that we observed.
PMID- 9765538
TI - Influence of water content and temperature on molecular mobility and
intracellular glasses in seeds and pollen
AB - Although the occurrence of intracellular glasses in seeds and pollen has been
established, physical properties such as rotational correlation times and
viscosity have not been studied extensively. Using electron paramagnetic
resonance spectroscopy, we examined changes in the molecular mobility of the
hydrophilic nitroxide spin probe 3-carboxy-proxyl during melting of intracellular
glasses in axes of pea (Pisum sativum L.) seeds and cattail (Typha latifolia L. )
pollen. The rotational correlation time of the spin probe in intracellular
glasses of both organisms was approximately 10(-3) s. Using the distance between
the outer extrema of the electron paramagnetic resonance spectrum (2Azz) as a
measure of molecular mobility, we found a sharp increase in mobility at a
definite temperature during heating. This temperature increased with decreasing
water content of the samples. Differential scanning calorimetry data on these
samples indicated that this sharp increase corresponded to melting of the glassy
matrix. Molecular mobility was found to be inversely correlated with storage
stability. With decreasing water content, the molecular mobility reached a
minimum, and increased again at very low water content. Minimum mobility and
maximum storage stability occurred at a similar water content. This correlation
suggests that storage stability might be at least partially controlled by
molecular mobility. At low temperatures, when storage longevity cannot be
determined on a realistic time scale, 2Azz measurements can provide an estimate
of the optimum storage conditions.
PMID- 9765539
TI - Natural genetic transformation by agrobacterium rhizogenes . Annual flowering in
two biennials, belgian endive and carrot
AB - Genetic transformation of Belgian endive (Cichorium intybus) and carrot (Daucus
carota) by Agrobacterium rhizogenes resulted in a transformed phenotype,
including annual flowering. Back-crossing of transformed (R1) endive plants
produced a line that retained annual flowering in the absence of the other traits
associated with A. rhizogenes transformation. Annualism was correlated with the
segregation of a truncated transferred DNA (T-DNA) insertion. During vegetative
growth, carbohydrate reserves accumulated normally in these annuals, and they
were properly mobilized prior to anthesis. The effects of individual root
inducing left-hand T-DNA genes on flowering were tested in carrot, in which rolC
(root locus) was the primary promoter of annualism and rolD caused extreme
dwarfism. We discuss the possible adaptive significance of this attenuation of
the phenotypic effects of root-inducing left-hand T-DNA.
PMID- 9765540
TI - A phosphothreonine residue at the C-terminal end of the plasma membrane H+-ATPase
is protected by fusicoccin-induced 14-3-3 binding.
AB - We have isolated the plasma membrane H+-ATPase in a phosphorylated form from
spinach (Spinacia oleracea L.) leaf tissue incubated with fusicoccin, a fungal
toxin that induces irreversible binding of 14-3-3 protein to the C terminus of
the H+-ATPase, thus activating H+ pumping. We have identified threonine-948, the
second residue from the C-terminal end of the H+-ATPase, as the phosphorylated
amino acid. Turnover of the phosphate group of phosphothreonine-948 was inhibited
by 14-3-3 binding, suggesting that this residue may form part of a binding motif
for 14-3-3. This is the first identification to our knowledge of an in vivo
phosphorylation site in the plant plasma membrane H+-ATPase.
PMID- 9765541
TI - Evidence that auxin-induced growth of tobacco leaf tissues does not involve cell
wall acidification
AB - Interveinal strips (10 x 1.5 mm) excised from growing tobacco (Nicotiana tabacum
L. cv Xanthi) leaves have an auxin-specific, epinastic growth response that is
developmentally regulated and is not the result of ethylene induction (C.P.
Keller, E. Van Volkenburgh [1997] Plant Physiol 113: 603-610). We report here
that auxin (10 &mgr;M naphthalene acetic acid) treatment of strips does not
result in plasma membrane hyperpolarization or detectable proton efflux. This
result is in contrast to the expected responses elicited by 1 &mgr;M fusicoccin
(FC) treatment, which in other systems mimics auxin growth promotion through
stimulation of the plasma membrane H+-ATPase and resultant acid wall loosening;
FC produced both hyperpolarization and proton efflux in leaf strips. FC-induced
growth was much more inhibited by a strong neutral buffer than was auxin-induced
growth. Measurements of the osmotic concentration of strips suggested that
osmotic adjustment plays no role in the auxin-induced growth response. Although
cell wall loosening of some form appears to be involved, taken together, our
results suggest that auxin-induced growth stimulation of tobacco leaf strips
results primarily from a mechanism not involving acid growth.
PMID- 9765542
TI - Intermediates of salicylic acid biosynthesis in tobacco
AB - Salicylic acid (SA) is an important component of systemic-acquired resistance in
plants. It is synthesized from benzoic acid (BA) as part of the phenylpropanoid
pathway. Benzaldehyde (BD), a potential intermediate of this pathway, was found
in healthy and tobacco mosaic virus (TMV)-inoculated tobacco (Nicotiana tabacum
L. cv Xanthi-nc) leaf tissue at 100 ng/g fresh weight concentrations as measured
by gas chromatography-mass spectrometry. BD was also emitted as a volatile
organic compound from tobacco tissues. Application of gaseous BD to plants
enclosed in jars caused a 13-fold increase in SA concentration, induced the
accumulation of the pathogenesis-related transcript PR-1, and increased the
resistance of tobacco to TMV inoculation. [13C6]BD and [2H5]benzyl alcohol were
converted to BA and SA. Labeling experiments using [13C1]Phe in temperature
shifted plants inoculated with the TMV showed high enrichment of cinnamic acids
(72%), BA (34%), and SA (55%). The endogenous BD, however, contained
nondetectable enrichment, suggesting that BD was not the intermediate between
cinnamic acid and BA. These results show that BD and benzyl alcohol promote SA
accumulation and expression of defense responses in tobacco, and provide insight
into the early steps of SA biosynthesis.
PMID- 9765543
TI - Does a low nitrogen supply necessarily lead to acclimation of photosynthesis to
elevated CO2?
AB - Long-term exposure of plants to elevated partial pressures of CO2 (pCO2) often
depresses photosynthetic capacity. The mechanistic basis for this photosynthetic
acclimation may involve accumulation of carbohydrate and may be promoted by
nutrient limitation. However, our current knowledge is inadequate for making
reliable predictions concerning the onset and extent of acclimation. Many studies
have sought to investigate the effects of N supply but the methodologies used
generally do not allow separation of the direct effects of limited N availability
from those caused by a N dilution effect due to accelerated growth at elevated
pCO2. To dissociate these interactions, wheat (Triticum aestivum L.) was grown
hydroponically and N was added in direct proportion to plant growth.
Photosynthesis did not acclimate to elevated pCO2 even when growth was restricted
by a low-N relative addition rate. Ribulose-1, 5-bisphosphate
carboxylase/oxygenase activity and quantity were maintained, there was no
evidence for triose phosphate limitation of photosynthesis, and tissue N content
remained within the range recorded for healthy wheat plants. In contrast, wheat
grown in sand culture with N supplied at a fixed concentration suffered
photosynthetic acclimation at elevated pCO2 in a low-N treatment. This was
accompanied by a significant reduction in the quantity of active ribulose-1, 5
bisphosphate carboxylase/oxygenase and leaf N content.
PMID- 9765544
TI - Characterization of starch-debranching enzymes in pea embryos
AB - Two distinct types of debranching enzymes have been identified in developing pea
(Pisum sativum L.) embryos using native gel analysis and tests of substrate
preference on purified or partially purified activities. An isoamylase-like
activity capable of hydrolyzing amylopectin and glycogen but not pullulan is
present throughout development and is largely or entirely confined to the
plastid. Activities capable of hydrolyzing pullulan are present both inside and
outside of the plastid, and extraplastidial activity increases relative to the
plastidial activity during development. Both types of debranching enzyme are also
present in germinating embryos. We argue that debranching enzymes are likely to
have a role in starch metabolism in the plastid of the developing embryo and in
starch degradation during germination.
PMID- 9765545
TI - Characterization of transgenic tobacco with an increased alpha-linolenic acid
level
AB - Microsomal omega-3 fatty acid desaturase catalyzes the conversion of 18:2
(linoleic acid) to 18:3 (alpha-linolenic acid) in phospholipids, which are the
main constituents of extrachloroplast membranes. Transgenic tobacco (Nicotiana
tabacum) plants with increased 18:3 contents (designated SIIn plants) were
produced through the introduction of a construct with the tobacco microsomal
omega-3 fatty acid desaturase gene under the control of the highly efficient
promoter containing the E12Omega sequence. 18:3 contents in the SIIn plants were
increased by about 40% in roots and by about 10% in leaves compared with the
control plants. With regard to growth at 15 degreesC and 25 degreesC and the
ability to tolerate chilling at 1 degreesC and 5 degreesC, there were no
discernible differences between the SIIn and the control plants. Freezing
tolerance in leaves and roots, which was assessed by electrolyte leakage, was
almost the same between the SIIn and the control plants. The fluidity of plasma
membrane from the SIIn plants was almost the same as that of the control plants.
These results indicate that an increase in the 18:3 level in phospholipids is not
directly involved in compensation for the diminishment in growth or membrane
properties observed under low temperatures.
PMID- 9765546
TI - The role of the alternative oxidase in stabilizing the in vivo reduction state of
the ubiquinone pool and the activation state of the alternative oxidase
AB - A possible function for the alternative (nonphosphorylating) pathway is to
stabilize the reduction state of the ubiquinone pool (Qr/Qt), thereby avoiding an
increase in free radical production. If the Qr/Qt were stabilized by the
alternative pathway, then Qr/Qt should be less stable when the alternative
pathway is blocked. Qr/Qt increased when we exposed roots of Poa annua (L.) to
increasing concentrations of KCN (an inhibitor of the cytochrome pathway).
However, when salicylhydroxamic acid, an inhibitor of the alternative pathway,
was added at the same time, Qr/Qt increased significantly more. Therefore, we
conclude that the alternative pathway stabilizes Qr/Qt. Salicylhydroxamic acid
increasingly inhibited respiration with increasing concentrations of KCN. In the
experiments described here the alternative oxidase protein was invariably in its
reduced (high-activity) state. Therefore, changes in the reduction state of the
alternative oxidase cannot account for an increase in activity of the alternative
pathway upon titration with KCN. The pyruvate concentration in intact roots
increased only after the alternative pathway was blocked or the cytochrome
pathway was severely inhibited. The significance of the pyruvate concentration
and Qr/Qt on the activity of the alternative pathway in intact roots is
discussed.
PMID- 9765547
TI - Two genetically separable phases of growth inhibition induced by blue light in
Arabidopsis seedlings.
AB - High fluence-rate blue light (BL) rapidly inhibits hypocotyl growth in
Arabidopsis, as in other species, after a lag time of 30 s. This growth
inhibition is always preceded by the activation of anion channels. The membrane
depolarization that results from the activation of anion channels by BL was only
30% of the wild-type magnitude in hy4, a mutant lacking the HY4 BL receptor. High
resolution measurements of growth made with a computer-linked displacement
transducer or digitized images revealed that BL caused a rapid inhibition of
growth in wild-type and hy4 seedlings. This inhibition persisted in wild-type
seedlings during more than 40 h of continuous BL. By contrast, hy4 escaped from
the initial inhibition after approximately 1 h of BL and grew faster than wild
type for approximately 30 h. Wild-type seedlings treated with 5-nitro-2-(3
phenylpropylamino)-benzoic acid, a potent blocker of the BL-activated anion
channel, displayed rapid growth inhibition, but, similar to hy4, these seedlings
escaped from inhibition after approximately 1 h of BL and phenocopied the mutant
for at least 2.5 h. The effects of 5-nitro-2-(3-phenylpropylamino)-benzoic acid
and the HY4 mutation were not additive. Taken together, the results indicate that
BL acts through HY4 to activate anion channels at the plasma membrane, causing
growth inhibition that begins after approximately 1 h. Neither HY4 nor anion
channels appear to participate greatly in the initial phase of inhibition.
PMID- 9765548
TI - Purification and characterization of NADP+-linked isocitrate dehydrogenase from
scots pine . Evidence for different physiological roles of the enzyme in primary
development
AB - NADP+-isocitrate dehydrogenase (NADP+-IDH; EC 1.1.1.42) is involved in the supply
of 2-oxoglutarate for ammonia assimilation and glutamate synthesis in higher
plants through the glutamine synthetase/glutamate synthase (GS/GOGAT) cycle. Only
one NADP+-IDH form of cytosolic localization was detected in green cotyledons of
pine (Pinus spp.) seedlings. The pine enzyme was purified and exhibited molecular
and kinetic properties similar to those described for NADP+-IDH from angiosperm,
with a higher catalytic efficiency (10(5) M-1 s-1) than the deduced efficiencies
for GS and GOGAT in higher plants. A polyclonal antiserum was raised against pine
NADP+-IDH and used to assess protein expression in the seedlings. Steady-state
levels of NADP+-IDH were coordinated with GS during seed germination and were
associated with GS/GOGAT enzymes during chloroplast biogenesis, suggesting that
NADP+-IDH is involved in the provision of carbon skeletons for the synthesis of
nitrogen-containing molecules. However, a noncoordinated pattern of NADP+-IDH and
GS/GOGAT was observed in advanced stages of cotyledon development and in the
hypocotyl. A detailed analysis in hypocotyl sections revealed that NADP+-IDH
abundance was inversely correlated with the presence of GS, GOGAT, and ribulose
1,5-bisphosphate carboxylase/oxygenase but was associated with the
differentiation of the organ. These results cannot be explained by the accepted
role of the enzyme in nitrogen assimilation and strongly suggest that NADP+-IDH
may have other, as-yet-unknown, biological functions.
PMID- 9765549
TI - Carbohydrate and amino acid metabolism in the eucalyptus globulus-pisolithus
tinctorius ectomycorrhiza during glucose utilization
AB - The metabolism of [1-13C]glucose in Pisolithus tinctorius cv Coker & Couch, in
uninoculated seedlings of Eucalyptus globulus bicostata ex Maiden cv Kirkp., and
in the E. globulus-P. tinctorius ectomycorrhiza was studied using nuclear
magnetic resonance spectroscopy. In roots of uninoculated seedlings, the 13C
label was mainly incorporated into sucrose and glutamine. The ratio (13C3 +
13C2)/13C4 of glutamine was approximately 1.0 during the time-course experiment,
indicating equivalent contributions of phosphoenolpyruvate carboxylase and
pyruvate dehydrogenase to the production of alpha-ketoglutarate used for
synthesis of this amino acid. In free-living P. tinctorius, most of the 13C label
was incorporated into mannitol, trehalose, glutamine, and alanine, whereas
arabitol, erythritol, and glutamate were weakly labeled. Amino acid biosynthesis
was an important sink of assimilated 13C (43%), and anaplerotic CO2 fixation
contributed 42% of the C flux entering the Krebs cycle. In ectomycorrhizae,
sucrose accumulation was decreased in the colonized roots compared with
uninoculated control plants, whereas 13C incorporation into arabitol and
erythritol was nearly 4-fold higher in the symbiotic mycelium than in the free
living fungus. It appears that fungal utilization of glucose in the symbiotic
state is altered and oriented toward the synthesis of short-chain polyols.
PMID- 9765550
TI - Superoxide dismutase in Arabidopsis: an eclectic enzyme family with disparate
regulation and protein localization.
AB - A number of environmental stresses can lead to enhanced production of superoxide
within plant tissues, and plants are believed to rely on the enzyme superoxide
dismutase (SOD) to detoxify this reactive oxygen species. We have identified
seven cDNAs and genes for SOD in Arabidopsis. These consist of three CuZnSODs
(CSD1, CSD2, and CSD3), three FeSODs (FSD1, FSD2, and FSD3), and one MnSOD
(MSD1). The chromosomal location of these seven SOD genes has been established.
To study this enzyme family, antibodies were generated against five proteins:
CSD1, CSD2, CSD3, FSD1, and MSD1. Using these antisera and nondenaturing
polyacrylamide gel electrophoresis enzyme assays, we identified protein and
activity for two CuZnSODs and for FeSOD and MnSOD in Arabidopsis rosette tissue.
Additionally, subcellular fractionation studies revealed the presence of CSD2 and
FeSOD protein within Arabidopsis chloroplasts. The seven SOD mRNAs and the four
proteins identified were differentially regulated in response to various light
regimes, ozone fumigation, and ultraviolet-B irradiation. To our knowledge, this
is the first report of a large-scale analysis of the regulation of multiple SOD
proteins in a plant species.
PMID- 9765551
TI - Rapid Up-regulation of HKT1, a high-affinity potassium transporter gene, in roots
of barley and wheat following withdrawal of potassium
AB - High-affinity K+ uptake in plant roots is rapidly up-regulated when K+ is
withheld and down-regulated when K+ is resupplied. These processes make important
contributions to plant K+ homeostasis. A cDNA coding for a high-affinity K+
transporter, HKT1, was earlier cloned from wheat (Triticum aestivum L.) roots and
functionally characterized. We demonstrate here that in both barley (Hordeum
vulgare L.) and wheat roots, a rapid and large up-regulation of HKT1 mRNA levels
resulted when K+ was withdrawn from growth media. This effect was specific for
K+; withholding N caused a modest reduction of HKT1 mRNA levels. Up-regulation of
HKT1 transcript levels in barley roots occurred within 4 h of removing K+, which
corresponds to the documented increase of high-affinity K+ uptake in roots
following removal of K+. Increased expression of HKT1 mRNA was evident before a
decline in total root K+ concentration could be detected. Resupply of 1 mM K+ was
sufficient to strongly reduce HKT1 transcript levels. In wheat root cortical
cells, both membrane depolarizations in response to 100 &mgr;M K+, Cs+, and Rb+,
and high-affinity K+ uptake were enhanced by K+ deprivation. Thus, in both plant
systems the observed physiological changes associated with manipulating external
K+ supply were correlated with levels of HKT1 mRNA expression. Implications of
these findings for K+ sensing and regulation of the HKT1 mRNA levels in plant
roots are discussed.
PMID- 9765553
TI - Differential expression of alternative oxidase genes in soybean cotyledons during
postgerminative development
AB - The expression of the alternative oxidase (AOX) was investigated during cotyledon
development in soybean (Glycine max [L.] Merr.) seedlings. The total amount of
AOX protein increased throughout development, not just in earlier stages as
previously thought, and was correlated with the increase in capacity of the
alternative pathway. Each AOX isoform (AOX1, AOX2, and AOX3) showed a different
developmental trend in mRNA abundance, such that the increase in AOX protein and
capacity appears to involve a shift in gene expression from AOX2 to AOX3. As the
cotyledons aged, the size of the mitochondrial ubiquinone pool decreased. We
discuss how this and other factors may affect the alternative pathway activity
that results from the developmental regulation of AOX expression.
PMID- 9765554
TI - Acclimation of photosynthesis to elevated CO2 under low-nitrogen nutrition is
affected by the capacity for assimilate utilization. Perennial ryegrass under
free-Air CO2 enrichment
AB - Acclimation of photosynthesis to elevated CO2 has previously been shown to be
more pronounced when N supply is poor. Is this a direct effect of N or an
indirect effect of N by limiting the development of sinks for photoassimilate?
This question was tested by growing a perennial ryegrass (Lolium perenne) in the
field under elevated (60 Pa) and current (36 Pa) partial pressures of CO2 (pCO2)
at low and high levels of N fertilization. Cutting of this herbage crop at 4- to
8-week intervals removed about 80% of the canopy, therefore decreasing the ratio
of photosynthetic area to sinks for photoassimilate. Leaf photosynthesis, in vivo
carboxylation capacity, carbohydrate, N, ribulose-1,5-bisphosphate
carboxylase/oxygenase, sedoheptulose-1,7-bisphosphatase, and chloroplastic
fructose-1, 6-bisphosphatase levels were determined for mature lamina during two
consecutive summers. Just before the cut, when the canopy was relatively large,
growth at elevated pCO2 and low N resulted in significant decreases in
carboxylation capacity and the amount of ribulose-1,5-bisphosphate
carboxylase/oxygenase protein. In high N there were no significant decreases in
carboxylation capacity or proteins, but chloroplastic fructose-1,6-bisphosphatase
protein levels increased significantly. Elevated pCO2 resulted in a marked and
significant increase in leaf carbohydrate content at low N, but had no effect at
high N. This acclimation at low N was absent after the harvest, when the canopy
size was small. These results suggest that acclimation under low N is caused by
limitation of sink development rather than being a direct effect of N supply on
photosynthesis.
PMID- 9765552
TI - Comparative analysis of the regulation of expression and structures of two
evolutionarily divergent genes for Delta1-pyrroline-5-carboxylate synthetase from
tomato.
AB - We isolated two tomato (Lycopersicon esculentum) cDNA clones, tomPRO1 and
tomPRO2, specifying Delta1-pyrroline-5-carboxylate synthetase (P5CS), the first
enzyme of proline (Pro) biosynthesis. tomPRO1 is unusual because it resembles
prokaryotic polycistronic operons (M.G. Garcia-Rios, T. Fujita, P.C. LaRosa, R.D.
Locy, J.M. Clithero, R.A. Bressan, L.N. Csonka [1997] Proc Natl Acad Sci USA 94:
8249-8254), whereas tomPRO2 encodes a full-length P5CS. We analyzed the
accumulation of Pro and the tomPRO1 and tomPRO2 messages in response to NaCl
stress and developmental signals. Treatment with 200 mM NaCl resulted in a >60
fold increase in Pro levels in roots and leaves. However, there was a <3-fold
increase in the accumulation of the tomPRO2 message and no detectable induction
in the level of the tomPRO1 message in response to NaCl stress. Although pollen
contained approximately 100-fold higher levels of Pro than other plant tissues,
there was no detectable increase in the level of either message in pollen. We
conclude that transcriptional regulation of these genes for P5CS is probably not
important for the osmotic or pollen-specific regulation of Pro synthesis in
tomato. Using restriction fragment-length polymorphism mapping, we determined the
locations of tomPRO1 and tomPRO2 loci in the tomato nuclear genome. Sequence
comparison suggested that tomPRO1 is similar to prokaryotic P5CS loci, whereas
tomPRO2 is closely related to other eukaryotic P5CS genes.
PMID- 9765555
TI - Domains of a transit sequence required for in vivo import in Arabidopsis
chloroplasts.
AB - Nuclear-encoded precursors of chloroplast proteins are synthesized with an amino
terminal cleavable transit sequence, which contains the information for
chloroplastic targeting. To determine which regions of the transit sequence are
most important for its function, the chloroplast uptake and processing of a full
length ferredoxin precursor and four mutants with deletions in adjacent regions
of the transit sequence were analyzed. Arabidopsis was used as an experimental
system for both in vitro and in vivo import. The full-length wild-type precursor
translocated efficiently into isolated Arabidopsis chloroplasts, and upon
expression in transgenic Arabidopsis plants only mature-sized protein was
detected, which was localized inside the chloroplast. None of the deletion
mutants was imported in vitro. By analyzing transgenic plants, more subtle
effects on import were observed. The most N-terminal deletion resulted in a fully
defective transit sequence. Two deletions in the middle region of the transit
sequence allowed translocation into the chloroplast, although with reduced
efficiencies. One deletion in this region strongly reduced mature protein
accumulation in older plants. The most C-terminal deletion was translocated but
resulted in defective processing. These results allow the dissection of the
transit sequence into separate functional regions and give an in vivo basis for a
domain-like structure of the ferredoxin transit sequence.
PMID- 9765556
TI - Rapid regulation by acid pH of cell wall adjustment and leaf growth in maize
plants responding to reversal of water stress
AB - The role of acid secretion in regulating short-term changes in growth rate and
wall extensibility was investigated in emerging first leaves of intact, water
stressed maize (Zea mays L.) seedlings. A novel approach was used to measure leaf
responses to injection of water or solutions containing potential regulators of
growth. Both leaf elongation and wall extensibility, as measured with a whole
plant creep extensiometer, increased dramatically within minutes of injecting
water, 0.5 mM phosphate, or strong (50 mM) buffer solutions with pH = 5.0 into
the cell-elongation zone of water-stressed leaves. In contrast, injecting buffer
solutions at pH >/= 5.5 inhibited these fast responses. Solutions containing 0.5
mM orthovanadate or erythrosin B to inhibit wall acidification by plasma membrane
H+-ATPases were also inhibitory. Thus, cell wall extensibility and leaf growth in
water-stressed plants remained inhibited, despite the increased availability of
(injected) water when accompanying increases in acid-induced wall loosening were
prevented. However, growth was stimulated when pH 4.5 buffers were included with
the vanadate injections. These findings suggest that increasing the availability
of water to expanding cells in water-stressed leaves signals rapid increases in
outward proton pumping by plasma membrane H+-ATPases. Resultant increases in cell
wall extensibility participate in the regulation of water uptake, cell expansion,
and leaf growth.
PMID- 9765557
TI - Characterization of multiple regions involved in replication and mobilization of
plasmid pNZ4000 coding for exopolysaccharide production in Lactococcus lactis.
AB - We characterized the regions involved in replication and mobilization of the 40
kb plasmid pNZ4000, encoding exopolysaccharide (EPS) production in Lactococcus
lactis NIZO B40. The plasmid contains four highly conserved replication regions
with homologous rep genes (repB1, repB2, repB3, and repB4) that belong to the
lactococcal theta replicon family. Subcloning of each replicon individually
showed that all are functional and compatible in L. lactis. Plasmid pNZ4000 and
genetically labeled derivatives could be transferred to different L. lactis
strains by conjugation, and pNZ4000 was shown to be a mobilization plasmid. Two
regions involved in mobilization were identified near two of the replicons; both
included an oriT sequence rich in inverted repeats. Conjugative mobilization of
the nonmobilizable plasmid pNZ124 was promoted by either one of these oriT
sequences, demonstrating their functionality. One oriT sequence was followed by a
mobA gene, coding for a trans-acting protein, which increased the frequency of
conjugative transfer 100-fold. The predicted MobA protein and the oriT sequences
show protein and nucleotide similarity, respectively, with the relaxase and with
the inverted repeat and nic site of the oriT from the Escherichia coli plasmid
R64. The presence on pNZ4000 of four functional replicons, two oriT sequences,
and several insertion sequence-like elements strongly suggests that this EPS
plasmid is a naturally occurring cointegrate.
PMID- 9765558
TI - Iron-responsive gene regulation in a campylobacter jejuni fur mutant.
AB - The expression of iron-regulated systems in gram-negative bacteria is generally
controlled by the Fur protein, which represses the transcription of iron
regulated promoters by using Fe2+ as a cofactor. Mutational analysis of the
Campylobacter jejuni fur gene was carried out by generation of a set of mutant
copies of fur which had a kanamycin or chloramphenicol resistance gene introduced
into the regions encoding the N and C termini of the Fur protein. The mutated
genes were recombined into the C. jejuni NCTC 11168 chromosome, and putative
mutants were confirmed by Southern hybridization. C. jejuni mutants were obtained
only when the resistance genes were transcribed in the same orientation as the
fur gene. The C. jejuni fur mutant grew slower than the parental strain.
Comparison of protein profiles of fractionated C. jejuni cells grown in low- or
high-iron medium indicated derepressed expression of three iron-regulated outer
membrane proteins with molecular masses of 70, 75, and 80 kDa. Characterization
by N-terminal amino acid sequencing showed the 75-kDa protein to be identical to
CfrA, a Campylobacter coli siderophore receptor homologue, whereas the 70-kDa
protein was identified as a new siderophore receptor homologue. Periplasmic
fractions contained four derepressed proteins with molecular masses of 19, 29,
32, and 36 kDa. The 19-kDa protein has been previously identified, but its
function is unknown. The cytoplasmic fraction contained two iron-repressed and
two iron-induced proteins with molecular masses of 26, 55, 31, and 40 kDa,
respectively. The two iron-repressed proteins have been previously identified as
the oxidative stress defense proteins catalase (KatA) and alkyl hydroperoxide
reductase (AhpC). AhpC and KatA were still iron regulated in the fur mutant,
suggesting the presence of Fur-independent iron regulation. Further analysis of
the C. jejuni iron and Fur regulons by using two-dimensional gel electrophoresis
demonstrated the total number of iron- and Fur-regulated proteins to be lower
than for other bacterial pathogens.
PMID- 9765559
TI - Domain structure of the ATP-binding-cassette protein MalK of salmonella
typhimurium as assessed by coexpressed half molecules and LacK'-'MalK chimeras.
AB - ATP-binding-cassette (ABC) subunit MalK of the binding protein-dependent
transport system for maltose of Salmonella typhimurium and Escherichia coli is
crucial to the transport process but also exhibits a repressing activity on other
genes of the maltose regulon. The latter function has been attributed to a
carboxy-terminal extension by which MalK differs in length from a prototype ABC
protein. In order to define the boundaries of putative functional domains of
MalK, we have analyzed pairs of N- and C-terminally truncated MalK proteins of S.
typhimurium. Coexpressed half molecules of about equal lengths (MalKN1: residues
1 to 179; MalKC1: residues 179 to 369) restored the transport activity of a malK
strain and displayed substantial regulatory activity. The same regulatory
activity was obtained when malKC1 was expressed separately. These results
indicate that a covalent linkage is not absolutely essential for function and
that the protein might be composed of two structurally distinct entities. To
elucidate further the minimal structural requirements for the regulatory function
of MalK, we have studied chimeric proteins that have C-terminal portions of MalK
fused to the corresponding amino-terminal fragments of its close homolog LacK.
Functional analyses revealed that a fusion containing only the C-terminal
extension of MalK (Q263 to V369) is sufficient to display half-maximal regulatory
activity. This activity increased with the lengths of the MalK portions present
in the chimeras. Furthermore, the failure of two chimeras to support maltose
transport suggests a structurally critical region between residues 243 and 264.
In the absence of a crystal structure, this work contributes to the understanding
of the multiple functions of MalK.
PMID- 9765560
TI - Identification and characterization of IS1411, a new insertion sequence which
causes transcriptional activation of the phenol degradation genes in Pseudomonas
putida.
AB - A new insertion sequence (IS element), IS1411, was identified downstream of the
phenol degradation genes pheBA that originated from plasmid DNA of Pseudomonas
sp. strain EST1001. According to sequence analysis, IS1411 belongs to a new
family of IS elements that has recently been named the ISL3 family (J. Mahillon
and M. Chandler, Microbiol. Mol. Biol. Rev. 62:725-774, 1998). IS1411 generates 8
bp duplication of the target DNA and carries 24-bp inverted repeats (IRs), highly
homologous to the IRs of other IS elements belonging to this family. IS1411 was
discovered as a result of insertional activation of promoterless pheBA genes in
Pseudomonas putida due to the presence of outward-directed promoters at the left
end of IS1411. Both promoters located on the IS element have sequences that are
similar to the consensus sequence of Escherichia coli sigma70. IS1411 can produce
IS circles, and the circle formation is enhanced when two copies of the element
are present in the same plasmid.
PMID- 9765561
TI - Conserved structural regions involved in the catalytic mechanism of Escherichia
coli K-12 WaaO (RfaI).
AB - Escherichia coli K-12 WaaO (formerly known as RfaI) is a nonprocessive alpha-1,3
glucosyltransferase, involved in the synthesis of the R core of
lipopolysaccharide. By comparing the amino acid sequence of WaaO with those of 11
homologous alpha-glycosyltransferases, four strictly conserved regions, I, II,
III, and IV, were identified. Since functionally related transferases are
predicted to have a similar architecture in the catalytic sites, it is assumed
that these four regions are directly involved in the formation of alpha
glycosidic linkage from alpha-linked nucleotide diphospho-sugar donor.
Hydrophobic cluster analysis revealed a conserved domain at the N termini of
these alpha-glycosyltransferases. This domain was similar to that previously
reported for beta-glycosyltransferases. Thus, this domain is likely to be
involved in the formation of beta-glycosidic linkage between the donor sugar and
the enzyme at the first step of the reaction. Site-directed mutagenesis analysis
of E. coli K-12 WaaO revealed four critical amino acid residues.
PMID- 9765563
TI - MinCD proteins control the septation process during sporulation of Bacillus
subtilis.
AB - Mutation of the divIVB locus in Bacillus subtilis causes misplacement of the
septum during cell division and allows the formation of anucleate minicells. The
divIVB locus contains five open reading frames (ORFs). The last two ORFs (minCD)
are homologous to minC and minD of Escherichia coli but a minE homolog is lacking
in B. subtilis. There is some similarity between minicell formation and the
asymmetric septation that normally occurs during sporulation in terms of polar
septum localization. However, it has been proposed that MinCD has no essential
role in sporulation septum formation. We have used electron microscopic studies
to show septation events during sporulation in some minD strains. We have
observed an unusually thin septum at the midcell position in minD and also in
minD spoIIE71 mutant cells. Fluorescence microscopy also localized a SpoIIE-green
fluorescent protein fusion protein at the midcell site in minD cells. We propose
that the MinCD complex plays an important role in asymmetric septum formation
during sporulation of B. subtilis cells.
PMID- 9765562
TI - Regulation of the Bacillus subtilis GlcT antiterminator protein by components of
the phosphotransferase system.
AB - Bacillus subtilis utilizes glucose as the preferred source of carbon and energy.
The sugar is transported into the cell by a specific permease of the
phosphoenolpyruvate:sugar phosphotransferase system (PTS) encoded by the ptsGHI
operon. Expression of this operon is induced by glucose and requires the action
of a positive transcription factor, the GlcT antiterminator protein. Glucose
availability is sensed by glucose-specific enzyme II (EIIGlc), the product of
ptsG. In the absence of inducer, the glucose permease negatively controls the
activity of the antiterminator. The GlcT antiterminator has a modular structure.
The isolated N-terminal part contains the RNA-binding protein and acts as a
constitutively acting antiterminator. GlcT contains two PTS regulation domains
(PRDs) at the C terminus. One (PRD-I) is the target of negative control exerted
by EIIGlc. A conserved His residue (His-104 in GlcT) is involved in inactivation
of GlcT in the absence of glucose. It was previously proposed that PRD-containing
transcriptional antiterminators are phosphorylated and concomitantly inactivated
in the absence of the substrate by their corresponding PTS permeases. The results
obtained with B. subtilis glucose permease with site-specific mutations suggest,
however, that the permease might modulate the phosphorylation reaction without
being the phosphate donor.
PMID- 9765564
TI - Identification of Candida albicans ALS2 and ALS4 and localization of als proteins
to the fungal cell surface.
AB - Additional genes in the growing ALS family of Candida albicans were isolated by
PCR screening of a genomic fosmid library with primers designed from the
consensus tandem-repeat sequence of ALS1. This procedure yielded fosmids encoding
ALS2 and ALS4. ALS2 and ALS4 conformed to the three-domain structure of ALS
genes, which consists of a central domain of tandemly repeated copies of a 108-bp
motif, an upstream domain of highly conserved sequences, and a domain of
divergent sequences 3' of the tandem repeats. Alignment of five predicted Als
protein sequences indicated conservation of N- and C-terminal hydrophobic regions
which have the hallmarks of secretory signal sequences and
glycosylphosphatidylinositol addition sites, respectively. Heterologous
expression of an N-terminal fragment of Als1p in Saccharomyces cerevisiae
demonstrated function of the putative signal sequence with cleavage following
Ala17. This signal sequence cleavage site was conserved in the four other Als
proteins analyzed, suggesting identical processing of each protein. Primary
structure features of the five Als proteins suggested a cell-surface
localization, which was confirmed by indirect immunofluorescence with an anti-Als
antiserum. Staining was observed on mother yeasts and germ tubes, although the
intensity of staining on the mother yeast decreased with elongation of the germ
tube. Similar to other ALS genes, ALS2 and ALS4 were differentially regulated.
ALS4 expression was correlated with the growth phase of the culture; ALS2
expression was not observed under many different in vitro growth conditions. The
data presented here demonstrate that ALS genes encode cell-surface proteins and
support the conclusion that the size and number of Als proteins on the C.
albicans cell surface vary with strain and growth conditions.
PMID- 9765565
TI - Nitrogen and oxygen regulation of Bacillus subtilis nasDEF encoding NADH
dependent nitrite reductase by TnrA and ResDE.
AB - The nitrate and nitrite reductases of Bacillus subtilis have two different
physiological functions. Under conditions of nitrogen limitation, these enzymes
catalyze the reduction of nitrate via nitrite to ammonia for the anabolic
incorporation of nitrogen into biomolecules. They also function catabolically in
anaerobic respiration, which involves the use of nitrate and nitrite as terminal
electron acceptors. Two distinct nitrate reductases, encoded by narGHI and nasBC,
function in anabolic and catabolic nitrogen metabolism, respectively. However, as
reported herein, a single NADH-dependent, soluble nitrite reductase encoded by
the nasDE genes is required for both catabolic and anabolic processes. The nasDE
genes, together with nasBC (encoding assimilatory nitrate reductase) and nasF
(required for nitrite reductase siroheme cofactor formation), constitute the nas
operon. Data presented show that transcription of nasDEF is driven not only by
the previously characterized nas operon promoter but also from an internal
promoter residing between the nasC and nasD genes. Transcription from both
promoters is activated by nitrogen limitation during aerobic growth by the
nitrogen regulator, TnrA. However, under conditions of oxygen limitation, nasDEF
expression and nitrite reductase activity were significantly induced. Anaerobic
induction of nasDEF required the ResDE two-component regulatory system and the
presence of nitrite, indicating partial coregulation of NasDEF with the
respiratory nitrate reductase NarGHI during nitrate respiration.
PMID- 9765566
TI - The NADP-dependent methylene tetrahydromethanopterin dehydrogenase in
Methylobacterium extorquens AM1.
AB - An NADP-dependent methylene tetrahydromethanopterin (H4MPT) dehydrogenase has
recently been proposed to be involved in formaldehyde oxidation to CO2 in
Methylobacterium extorquens AM1. We report here on the purification of this novel
enzyme to apparent homogeneity. Via the N-terminal amino acid sequence, it was
identified to be the mtdA gene product. The purified enzyme catalyzed the
dehydrogenation of methylene H4MPT with NADP+ rather than with NAD+, with a
specific activity of approximately 400 U/mg of protein. It also catalyzed the
dehydrogenation of methylene tetrahydrofolate (methylene H4F) with NADP+. With
methylene H4F as the substrate, however, the specific activity (26 U/mg) and the
catalytic efficiency (Vmax/Km) were approximately 20-fold lower than with
methylene H4MPT. Whereas the dehydrogenation of methylene H4MPT (E0 = -390 mV)
with NADP+ (E0 = -320 mV) proceeded essentially irreversibly, the dehydrogenation
of methylene H4F (E0 = -300 mV) was fully reversible. Comparison of the primary
structure of the NADP-dependent dehydrogenase from M. extorquens AM1 with those
of methylene H4F dehydrogenases from other bacteria and eucarya and with those of
methylene H4MPT dehydrogenases from methanogenic archaea revealed only marginally
significant similarity (<15%).
PMID- 9765567
TI - A chaperone in the HSP70 family controls production of extracellular fibrils in
Myxococcus xanthus.
AB - Three independent Tn5-lac insertions in the S1 locus of Myxococcus xanthus
inactivate the sglK gene, which is nonessential for growth but required for
social motility and multicellular development. The sequence of sglK reveals that
it encodes a homologue of the chaperone HSP70 (DnaK). The sglK gene is
cotranscribed with the upstream grpS gene, which encodes a GrpE homologue. Unlike
sglK, grpS is not required for social motility or development. Wild-type M.
xanthus is encased in extracellular polysaccharide filaments associated with the
multimeric fibrillin protein. Mutations in sglK inhibit cell cohesion, the
binding of Congo red, and the synthesis or secretion of fibrillin, indicating
that sglK mutants do not make fibrils. The fibR gene, located immediately
upstream of the grpS-sglK operon, encodes a product which is predicted to have a
sequence similar to those of the repressors of alginate biosynthesis in
Pseudomonas aeruginosa and Pseudomonas putida. Inactivation of fibR leads to the
overproduction of fibrillin, suggesting that M. xanthus fibril production and
Pseudomonas alginate production are regulated in analogous ways. M. xanthus and
Pseudomonas exopolysaccharides may play similar roles in a mechanism of social
motility conserved in these gram-negative bacteria.
PMID- 9765568
TI - Legionella pneumophila catalase-peroxidases: cloning of the katB gene and studies
of KatB function.
AB - Legionella pneumophila, the causative organism of Legionnaires' pneumonia, is
spread by aerosolization from man-made reservoirs, e.g. , water cooling towers
and air conditioning ducts, whose nutrient-poor conditions are conducive to
entrance into stationary phase. Exposure to starvation conditions is known to
induce several virulence traits in L. pneumophila. Since catalase-peroxidases
have been extremely useful markers of the stationary-phase response in many
bacterial species and may be an avenue for identifying virulence genes in L.
pneumophila, an investigation of these enzymes was initiated. L. pneumophila was
shown to contain two bifunctional catalase-peroxidases and to lack monofunctional
catalase and peroxidase. The gene encoding the KatB catalase-peroxidase was
cloned and sequenced, and lacZ fusion and null mutant strains were constructed.
Null mutants in katB are delayed in the infection and lysis of cultured
macrophage-like cell lines. KatB is similar to the KatG catalase-peroxidase of
Escherichia coli in its 20-fold induction during exponential growth and in
playing a role in resistance to hydrogen peroxide. Analysis of the changes in
katB expression and in the total catalase and peroxidase activity during growth
indicates that the 8- to 10-fold induction of peroxidase activity that occurs in
stationary phase is attributable to KatA, the second L. pneumophila catalase
peroxidase.
PMID- 9765569
TI - Escherichia coli promoters with UP elements of different strengths: modular
structure of bacterial promoters.
AB - The alpha subunit of Escherichia coli RNA polymerase (RNAP) participates in
promoter recognition through specific interactions with UP element DNA, a region
upstream of the recognition hexamers for the sigma subunit (the -10 and -35
hexamers). UP elements have been described in only a small number of promoters,
including the rRNA promoter rrnB P1, where the sequence has a very large (30- to
70-fold) effect on promoter activity. Here, we analyzed the effects of upstream
sequences from several additional E. coli promoters (rrnD P1, rrnB P2, lambda pR,
lac, merT, and RNA II). The relative effects of different upstream sequences were
compared in the context of their own core promoters or as hybrids to the lac core
promoter. Different upstream sequences had different effects, increasing
transcription from 1.5- to approximately 90-fold, and several had the properties
of UP elements: they increased transcription in vitro in the absence of accessory
protein factors, and transcription stimulation required the C-terminal domain of
the RNAP alpha subunit. The effects of the upstream sequences correlated
generally with their degree of similarity to an UP element consensus sequence
derived previously. Protection of upstream sequences by RNAP in footprinting
experiments occurred in all cases and was thus not a reliable indicator of UP
element strength. These data support a modular view of bacterial promoters in
which activity reflects the composite effects of RNAP interactions with
appropriately spaced recognition elements (-10, -35, and UP elements), each of
which contributes to activity depending on its similarity to the consensus.
PMID- 9765571
TI - Analogs of the autoinducer 3-oxooctanoyl-homoserine lactone strongly inhibit
activity of the TraR protein of Agrobacterium tumefaciens.
AB - The TraR and TraI proteins of Agrobacterium tumefaciens mediate cell-density
dependent expression of the Ti plasmid tra regulon. TraI synthesizes the
autoinducer pheromone N-(3-oxooctanoyl)-L-homoserine lactone (3-oxo-C8-HSL),
while TraR is an 3-oxo-C8-HSL-responsive transcriptional activator. We have
compared the abilities of 3-oxo-C8-HSL and 32 related compounds to activate
expression of a TraR-regulated promoter. In a strain that expresses wild-type
levels of TraR, only 3-oxo-C8-HSL was strongly stimulatory, four compounds were
detectably active only at high concentrations, and the remaining 28 compounds
were inactive. Furthermore, many of these compounds were potent antagonists. In
contrast, almost all of these compounds were stimulatory in a congenic strain
that overexpresses TraR and no compound was a potent antagonist. We propose a
model in which autoinducers enhance the affinity of TraR either for other TraR
monomers or for DNA binding sites and that overexpression of TraR potentiates
this interaction by mass action. Wild-type A. tumefaciens released a rather broad
spectrum of autoinducers, including several that antagonize induction of a wild
type strain. However, under all conditions tested, 3-oxo-C8-HSL was more abundant
than any other analog, indicating that other released autoinducers do not
interfere with tra gene induction. We conclude that (i) in wild-type strains,
only 3-oxo-C8-HSL significantly stimulates tra gene expression, while many
autoinducer analogs are potent antagonists; (ii) TraR overexpression increases
agonistic activity of autoinducer analogs, allowing sensitive biodetection of
many autoinducers; and (iii) autoinducer stimulatory activity is potentiated by
TraR overproduction, suggesting that autoinducers may shift an equilibrium
between TraR monomers and dimers or oligomers. When autoinducer specificities of
other quorum-sensing proteins are tested, care should be taken not to overexpress
those proteins.
PMID- 9765570
TI - Flk couples flgM translation to flagellar ring assembly in Salmonella
typhimurium.
AB - The hook-basal body (HBB) is a key intermediate structure in the flagellar
assembly pathway in Salmonella typhimurium. The FlgM protein inhibits the
flagellum-specific transcription factor sigma28 in the absence of the intact HBB
structure and is secreted out of the cell following HBB completion. The flk gene
encodes a positive regulator of the activity of FlgM at an assembly step just
prior to HBB completion: at the point of assembly of the P- and L-rings. FlgM
inhibition of sigma28-dependent class 3 flagellar gene transcription was relieved
in P- and L-ring assembly mutants (flgA, flgH, and flgI) by introduction of a
null mutation in the flk gene (J. E. Karlinsey et al., J. Bacteriol. 179:2389
2400, 1997). In P- and L-ring mutant strains, recessive mutations in flk resulted
in a reduction in intracellular FlgM levels to those seen in wild-type (Fla+)
strains. The reduction in intracellular FlgM levels by mutations in the flk gene
was concomitant with a 10-fold increase in transcription of the flgMN operon
compared to that of the isogenic flk+ strain, while transcription of the flgAMN
operon was unaffected. This was true for both direct measurement of the flgAMN
and flgMN mRNA transcripts by RNase T2 protection assays and for lac operon
fusions to either the flgAMN or flgMN promoter. Loss of Flk did not allow
secretion of FlgM through basal-body structures lacking the P- and L-rings.
Intracellular FlgM was stable to proteolysis, and turnover occurred primarily
after export out of the cell. Loss of Flk did not result in increased FlgM
turnover in either P- or L-ring mutant strains. With lacZ translational fusions
to flgM, a null mutation in flk resulted in a significant reduction of flgM-lacZ
mRNA translation, expressed from the class 3 flgMN promoter, in P- and L-ring
mutant strains. No reduction in either flgAMN or flgMN mRNA stability was
measured in the absence of Flk in Fla+, ring mutant, or HBB deletion strains. We
conclude that the reduction in the intracellular FlgM levels by mutation in the
flk gene is only at the level of flgM mRNA translation.
PMID- 9765572
TI - Methanococcus jannaschii flap endonuclease: expression, purification, and
substrate requirements.
AB - The flap endonuclease (FEN) of the hyperthermophilic archaeon Methanococcus
jannaschii was expressed in Escherichia coli and purified to homogeneity. FEN
retained activity after preincubation at 95 degrees C+ for 15 min. A pseudo-Y
shaped substrate was formed by hybridization of two partially complementary
oligonucleotides. FEN cleaved the strand with the free 5' end adjacent to the
single-strand-duplex junction. Deletion of the free 3' end prevented cleavage.
Hybridization of a complementary oligonucleotide to the free 3' end moved the
cleavage site by 1 to 2 nucleotides. Hybridization of excess complementary
oligonucleotide to the free 5' end failed to block cleavage, although this
substrate was refractory to cleavage by the 5'-3' exonuclease activity of Taq DNA
polymerase. For verification, the free 5' end was replaced by an internally
labeled hairpin structure. This structure was a substrate for FEN but became a
substrate for Taq DNA polymerase only after exonucleolytic cleavage had
destabilized the hairpin. A circular duplex substrate with a 5' single-stranded
branch was formed by primer extension of a partially complementary
oligonucleotide on virion phiX174. This denaturation-resistant substrate was used
to examine the effects of temperature and solution properties, such as pH, salt,
and divalent ion concentration on the turnover number of the enzyme.
PMID- 9765574
TI - Fumarate regulation of gene expression in Escherichia coli by the DcuSR (dcuSR
genes) two-component regulatory system.
AB - In Escherichia coli the genes encoding the anaerobic fumarate respiratory system
are transcriptionally regulated by C4-dicarboxylates. The regulation is effected
by a two-component regulatory system, DcuSR, consisting of a sensory histidine
kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the
dcuSR genes (previously yjdHG) at 93.7 min on the calculated E. coli map.
Inactivation of the dcuR and dcuS genes caused the loss of C4-dicarboxylate
stimulated synthesis of fumarate reductase (frdABCD genes) and of the anaerobic
fumarate-succinate antiporter DcuB (dcuB gene). DcuS is predicted to contain a
large periplasmic domain as the supposed site for C4-dicarboxylate sensing.
Regulation by DcuR and DcuS responded to the presence of the C4-dicarboxylates
fumarate, succinate, malate, aspartate, tartrate, and maleate. Since maleate is
not taken up by the bacteria under these conditions, the carboxylates presumably
act from without. Genes of the aerobic C4-dicarboxylate pathway encoding
succinate dehydrogenase (sdhCDAB) and the aerobic succinate carrier (dctA) are
only marginally or negatively regulated by the DcuSR system. The CitAB two
component regulatory system, which is highly similar to DcuSR, had no effect on
C4-dicarboxylate regulation of any of the genes.
PMID- 9765573
TI - Molecular cloning and expression analysis of the Rhodobacter capsulatus sodB
gene, encoding an iron superoxide dismutase.
AB - Genetic complementation of a sodA sodB Escherichia coli mutant strain was used to
clone Rhodobacter capsulatus genes involved in detoxification of superoxide
radicals. After sequence analysis, 1 of the 16 identical clones obtained by this
selection procedure was shown to contain an open reading frame with sequence
similarity to that coding for Fe-containing superoxide dismutases (SodB). The R.
capsulatus sodB gene was expressed in E. coli, and the nature of the metal ligand
was confirmed by inhibitor sensitivity assays with lysates from both bacterial
species. Activity staining of cleared Rhodobacter lysates resolved by
polyacrylamide gel electrophoresis indicated that SodB was the only superoxide
dismutase present in this phototrophic organism. The sodB gene was expressed at
low levels in R. capsulatus cells grown under anaerobic or semiaerobic
conditions, but expression was strongly induced upon exposure of the bacteria to
air or to methyl viologen. Attempts to construct a sodB mutant in this organism
by allelic exchange of the chromosomal copy of the gene with a suicide plasmid
containing a mutated sodB gene were unsuccessful, strongly suggesting that the
encoded superoxide dismutase is essential for viability of R. capsulatus in
aerobic cultures.
PMID- 9765575
TI - Novel rkp gene clusters of Sinorhizobium meliloti involved in capsular
polysaccharide production and invasion of the symbiotic nodule: the rkpK gene
encodes a UDP-glucose dehydrogenase.
AB - The production of exopolysaccharide (EPS) was shown to be required for the
infection process by rhizobia that induce the formation of indeterminate nodules
on the roots of leguminous host plants. In Sinorhizobium meliloti (also known as
Rhizobium meliloti) Rm41, a capsular polysaccharide (KPS) analogous to the group
II K antigens of Escherichia coli can replace EPS during symbiotic nodule
development and serve as an attachment site for the strain-specific bacteriophage
phi16-3. The rkpA to -J genes in the chromosomal rkp-1 region code for proteins
that are involved in the synthesis, modification, and transfer of an as-yet
unknown lipophilic molecule which might function as a specific lipid carrier
during KPS biosynthesis. Here we report that with a phage phi16-3-resistant
population obtained after random Tn5 mutagenesis, we have identified novel
mutants impaired in KPS production by genetic complementation and biochemical
studies. The mutations represent two novel loci, designated the rkp-2 and rkp-3
regions, which are required for the synthesis of rhizobial KPS. The rkp-2 region
harbors two open reading frames (ORFs) organized in monocistronic transcription
units. Although both genes are required for normal lipopolysaccharide production,
only the second one, designated rkpK, is involved in the synthesis of KPS. We
have demonstrated that RkpK possesses UDP-glucose dehydrogenase activity, while
the protein product of ORF1 might function as a UDP-glucuronic acid epimerase.
PMID- 9765576
TI - Different phenotypic classes of Sinorhizobium meliloti mutants defective in
synthesis of K antigen.
AB - For Sinorhizobium meliloti (also known as Rhizobium meliloti) AK631 to establish
effective symbiosis with alfalfa, it must be able to synthesize a symbiotically
active form of its K antigen, a capsular polysaccharide containing a Kdo (3-deoxy
D-manno-octulosonic acid) derivative. Previously isolated mutants defective in
the synthesis of K antigen are resistant to bacteriophage phi16-3. By screening
ca. 100,000 Tn5-mutagenized R. meliloti bacteria for resistance to bacteriophage
phi16-3, we isolated 119 mutants, 31 of which could not be complemented by genes
previously identified as being required for K-antigen synthesis. Of these 31 new
mutants, 13 were symbiotically defective and lacked the K antigen. Through
genetic and phenotypic analyses, we have grouped these mutants into four distinct
classes. Although all of these mutants lack the K antigen, many also have altered
lipopolysaccharides (LPS), suggesting that the biochemical pathways for the
synthesis of K antigen and LPS have common enzymatic steps. In addition, we have
found that these and other classes of K-antigen-defective mutants of S. meliloti
AK631 exhibit unique patterns of sensitivities to phage strains to which the
parental strain was resistant. Our studies have identified new classes of genes
required for both the synthesis of K antigen and the symbiotic proficiency of S.
meliloti AK631. Some of these classes of genes also play a role in LPS synthesis.
PMID- 9765577
TI - Point mutations in the integron integrase IntI1 that affect recombination and/or
substrate recognition.
AB - The site-specific recombinase IntI1 found in class 1 integrons catalyzes the
excision and integration of mobile gene cassettes, especially antibiotic
resistance gene cassettes, with a site-specific recombination system. The
integron integrase belongs to the tyrosine recombinase (phage integrase) family.
The members of this family, exemplified by the lambda integrase, do not share
extensive amino acid identities, but three invariant residues are found within
two regions, designated box I and box II. Two conserved residues are arginines,
one located in box I and one in box II, while the other conserved residue is a
tyrosine located at the C terminus of box II. We have analyzed the properties of
IntI1 variants carrying point mutations at the three conserved residues of the
family in in vivo recombination and in vitro substrate binding. We have made four
proteins with mutations of the conserved box I arginine (R146) and three mutants
with changes of the box II arginine (R280); of these, MBP-IntI1(R146K) and MBP
IntI1(R280K) bind to the attI1 site in vitro, but only MBP-IntI1(R280K) is able
to excise cassettes in vivo. However, the efficiency of recombination and DNA
binding for MBP-IntI1(R280K) is lower than that obtained with the wild-type MBP
IntI1. We have also made two proteins with mutations of the tyrosine residue
(Y312), and both mutant proteins are similar to the wild-type fusion protein in
their DNA-binding capacity but are unable to catalyze in vivo recombination.
PMID- 9765578
TI - Influence of the MexAB-OprM multidrug efflux system on quorum sensing in
Pseudomonas aeruginosa.
AB - Pseudomonas aeruginosa nalB mutants which hyperexpress the MexAB-OprM multidrug
efflux system produce reduced levels of several extracellular virulence factors
known to be regulated by quorum sensing. Such mutants also produce less acylated
homoserine lactone autoinducer PAI-1, consistent with an observed reduction in
lasI expression. These data suggest that PAI-1 is a substrate for MexAB-OprM, and
its resulting exclusion from cells hyperexpressing MexAB-OprM limits PAI-1
dependent activation of lasI and the virulence genes.
PMID- 9765580
TI - Analysis of the novel benzylsuccinate synthase reaction for anaerobic toluene
activation based on structural studies of the product.
AB - Recent studies of anaerobic toluene catabolism have demonstrated a novel reaction
for anaerobic hydrocarbon activation: the addition of the methyl carbon of
toluene to fumarate to form benzylsuccinate. In vitro studies of the anaerobic
benzylsuccinate synthase reaction indicate that the H atom abstracted from the
toluene methyl group during addition to fumarate is retained in the succinyl
moiety of benzylsuccinate. Based on structural studies of benzylsuccinate formed
during anaerobic, in vitro assays with denitrifying, toluene-mineralizing strain
T, we now report the following characteristics of the benzylsuccinate synthase
reaction: (i) it is highly stereospecific, resulting in >95% formation of the (+)
benzylsuccinic acid enantiomer [(R)-2-benzyl-3-carboxypropionic acid], and (ii)
active benzylsuccinate synthase does not contain an abstracted methyl H atom from
toluene at the beginning or at the end of a catalytic cycle.
PMID- 9765579
TI - The 20S proteasome of Streptomyces coelicolor.
AB - 20S proteasomes were purified from Streptomyces coelicolor A3(2) and shown to be
built from one alpha-type subunit (PrcA) and one beta-type subunit (PrcB). The
enzyme displayed chymotrypsin-like activity on synthetic substrates and was
sensitive to peptide aldehyde and peptide vinyl sulfone inhibitors and to the
Streptomyces metabolite lactacystin. Characterization of the structural genes
revealed an operon-like gene organization (prcBA) similar to Rhodococcus and
Mycobacterium spp. and showed that the beta subunit is encoded with a 53-amino
acid propeptide which is removed during proteasome assembly. The upstream DNA
region contains the conserved orf7 and an AAA ATPase gene (arc).
PMID- 9765581
TI - Efficiency of the pTF-FC2 pas poison-antidote stability system in Escherichia
coli is affected by the host strain, and antidote degradation requires the lon
protease.
AB - The stabilization of a test plasmid by the proteic, poison-antidote plasmid
addiction system (pas) of plasmid pTF-FC2 was host strain dependent, with a 100
fold increase in stability in Escherichia coli CSH50, a 2.5-fold increase in E.
coli JM105, and no detectable stabilization in E. coli strains JM107 and JM109.
The lethality of the PasB toxin was far higher in the E. coli strains in which
the pas was most effective. Models for the way in which poison-antidote systems
stabilize plasmids require that the antidote have a much higher rate of turnover
than that of the toxin. A decrease in host cell death following plasmid loss from
an E. coli lon mutant and a decrease in plasmid stability suggested that the Lon
protease plays a role in the rate of turnover of PasA antidote.
PMID- 9765582
TI - Autoregulation of the pTF-FC2 proteic poison-antidote plasmid addiction system
(pas) is essential for plasmid stabilization.
AB - The pasABC genes of the proteic plasmid addiction system of broad-host-range
plasmid pTF-FC2 were autoregulated. The PasA antidote was able to repress the
operon 25-fold on its own, and repression was increased to 100-fold when the PasB
toxin was also present. Autoregulation appears to be an essential requirement for
pas-mediated plasmid stabilization because when the pas genes were placed behind
the isopropyl-beta-D-thiogalactopyranoside (IPTG)-regulated tac promoter, they
were unable to stabilize a heterologous test plasmid.
PMID- 9765583
TI - Demonstration that the TyrR protein and RNA polymerase complex formed at the
divergent P3 promoter inhibits binding of RNA polymerase to the major promoter,
P1, of the aroP gene of Escherichia coli.
AB - In previous studies, we have identified three promoters (P1, P2, and P3) in the
regulatory region of the Escherichia coli aroP gene (P. Wang, J. Yang, and A. J.
Pittard, J. Bacteriol. 179:4206-4212, 1997). Both P1 and P2 can direct mRNA
synthesis for aroP expression, whereas P3 is a divergent promoter which overlaps
with P1. The repression of transcription from the major promoter, P1, has been
postulated to involve the activation of the divergent promoter, P3, by the TyrR
protein (P. Wang, J. Yang, B. Lawley, and A. J. Pittard, J. Bacteriol. 179:4213
4218, 1997). In the present study, we confirmed the proposed mechanism of P3
mediated repression of P1 transcription by studying the binding of RNA polymerase
to the promoters P1 and P3 in vitro in the presence and absence of TyrR protein
and its cofactors. Our results show that (i) only one RNA polymerase molecule can
bind to the DNA fragment carrying the aroP regulatory region, (ii) RNA polymerase
has a higher affinity for P1 than for either P2 or P3 and binds to P1 in the
absence of TyrR protein, (iii) in the presence of TyrR protein and its cofactor,
phenylalanine or tyrosine, RNA polymerase preferentially binds to P3, and (iv)
RNA polymerase does not respond to the activation-defective mutant TyrR protein
TyrR-RQ10 and remains bound to P1 in the presence of TyrR-RQ10 and either of the
cofactors.
PMID- 9765584
TI - Characterization of the mIHF gene of Mycobacterium smegmatis.
AB - Integration of mycobacteriophage L5 requires the mycobacterial integration host
factor (mIHF) in vitro. mIHF is a 105-residue heat-stable polypeptide that is not
obviously related to HU or any other small DNA-binding proteins. mIHF is most
abundant just prior to entry into stationary phase and is essential for the
viability of Mycobacterium smegmatis.
PMID- 9765585
TI - Gram-negative bacteria produce membrane vesicles which are capable of killing
other bacteria.
AB - Naturally produced membrane vesicles (MVs), isolated from 15 strains of gram
negative bacteria (Citrobacter, Enterobacter, Escherichia, Klebsiella,
Morganella, Proteus, Salmonella, and Shigella strains), lysed many gram-positive
(including Mycobacterium) and gram-negative cultures. Peptidoglycan zymograms
suggested that MVs contained peptidoglycan hydrolases, and electron microscopy
revealed that the murein sacculi were digested, confirming a previous modus
operandi (J. L. Kadurugamuwa and T. J. Beveridge, J. Bacteriol. 174:2767-2774,
1996). MV-sensitive bacteria possessed A1alpha, A4alpha, A1gamma, A2alpha, and
A4gamma peptidoglycan chemotypes, whereas A3alpha, A3beta, A3gamma, A4beta,
B1alpha, and B1beta chemotypes were not affected. Pseudomonas aeruginosa PAO1
vesicles possessed the most lytic activity.
PMID- 9765586
TI - Relationship between spontaneous aminoglycoside resistance in Escherichia coli
and a decrease in oligopeptide binding protein.
AB - Changes in the amount of oligopeptide binding protein (OppA) in spontaneous
kanamycin-resistant mutants of Escherichia coli were investigated. Among 20
colonies obtained from 10(8) cells cultured in the presence of 20 microgram of
kanamycin/ml, 1 colony had no detectable OppA and 7 colonies were mutants with
reduced amounts of OppA. Sensitivity of wild-type cells to kanamycin increased
slightly by transformation of the oppA gene, but the sensitivity of the mutants
increased greatly by the transformation. A mutant with no OppA was found to be a
nonsense mutant of the oppA gene at amino acid position 166. In a mutant having a
reduced level of OppA, the reduction was due to the decrease in OppA synthesis at
the translational level. These mutants were also resistant to other
aminoglycoside antibiotics, including streptomycin, neomycin, and isepamicin.
Isepamicin uptake activities decreased greatly in these two kinds of mutants. The
results support the proposition that aminoglycoside antibiotics are transported
into cells by the oligopeptide transport system, and that transport is an
important factor for spontaneous resistance to aminoglycoside antibiotics.
PMID- 9765587
TI - The nine genes of the Nocardia lactamdurans cephamycin cluster are transcribed
into large mRNAs from three promoters, two of them located in a bidirectional
promoter region.
AB - The nine biosynthesis genes of the Nocardia lactamdurans cephamycin cluster are
expressed as three different mRNAs initiating at promoters latp, cefDp, and
pcbABp, as shown by low-resolution S1 nuclease protection assays and Northern
blotting analysis. Bidirectional expression occurred from divergent promoters
(latp and cefDp) located in a 629-bp intergenic region that contains three
heptameric direct repeats similar to those recognized by members of the SARP
(Streptomyces antibiotic regulatory proteins) family. The lat gene is transcribed
in a single monocistronic transcript initiating at latp. A second unusually long
polycistronic mRNA (more than 16 kb) corresponding to six biosynthesis genes
(pcbAB, pcbC, cmcI, cmcJ, cefF, and cmcH) started at pcbABp. A third
polycistronic mRNA corresponding to the cefD and cefE genes started at cefDp.
PMID- 9765588
TI - A sequence based computational identification of a Drosophila developmentally
regulated TATA-less RNA polymerase II promoter and its experimental validation.
AB - Many RNA polymerase II promoters lack the characteristic TATA box sequence
located -25/-30 nucleotides upstream from the transcription start. In Drosophila,
half of the promoters identified so far are TATA-deficient. The yemanuclein-alpha
gene whose promoter activity is restricted to oogenesis, falls in this class. A
number of upstream and downstream promoter elements have been identified for some
TATA-less promoters. The yem-alpha promoter contains none of the consensus
elements identified so far. Our work was based on the assumption that the
physical parameters of the DNA could be used to predict the location of the yem
alpha promoter. A sequence based computational analysis allowed us to determine
the characteristic changes of DNA curvature and helix stability in the
presumptive regulatory region. Our experimental data were in good agreement with
the computational analysis. We have started to investigate the general value of
this approach by analyzing other promoters.
PMID- 9765589
TI - The major APN transcript of the alveolar type II epithelial cell originates from
a unique upstream promoter region.
AB - Aminopeptidase N (APN, EC 3.4.11.2) is an ectopeptidase expressed in lung at the
apical surface of alveolar type II epithelial cells. Its expression is
upregulated during fetal lung development. To begin to understand the regulation
of APN expression during lung development, we used the rapid modification of cDNA
ends (RACE) to clone the 5' end of the major APN transcript in rat lung and
alveolar type II cells. The cloned sequence revealed a unique 135 bp untranslated
exon which genomic cloning and restriction mapping indicated was located more
than 14 kb upstream from the coding sequence. A 172 bp genomic fragment flanking
the untranslated exon produced a high level of expression of a reporter gene in
transient transfection assays using a human lung adenocarcinoma cell line. The
DNA fragment includes elements known to be important for expression of lung
specific proteins, including the surfactant-associated proteins A, B, and C and
the Clara cell specific protein. Comparison of the APN genomic sequences and gene
structure from human and rat suggests that the exon present in the rat lung
transcript may result from the use of a previously uncharacterized APN promoter.
PMID- 9765590
TI - A putative lichenysin A synthetase operon in Bacillus licheniformis: initial
characterization.
AB - Certain Bacillus licheniformis strains isolated from oil wells have been shown to
produce a very effective biosurfactant, lichenysin A, which is structurally
similar to another less active lipopeptide, surfactin. Surfactin, like many small
peptides in prokaryotes and lower eukaryotes, is synthesized non-ribosomally by
multi-enzyme peptide synthetase complex. Analysis of several peptide synthetases
of bacterial and fungal origin has revealed a high degree of sequence
conservation. Two 35-mer oligonucleotides derived from highly conserved motifs
('core I' and 'core II') of surfactin synthetase were used to identify the cloned
putative operon of lichenysin A synthetase lchA from B. licheniformis BNP29, a
strain not amenable to genetic manipulation in a BAC system (F-plasmid-based
bacterial artificial chromosome) based on Escherichia coli and its single-copy
plasmid F-factor. A 32.4 kb fragment containing lichenysin A biosynthesis locus
was sequenced and analysed. The structural architecture of putative lichenysin A
synthetase protein containing seven amino acid (aa) activation-thiolation, two
epimerization and one thioesterase domains is discussed in terms of its
similarity to surfactin and other peptide synthetases. The 100 aa peptide chain
situated between the highly conserved signature sequences FDXX and NXYGPTE(IV)X
within amino acid binding domains of peptide synthetases is proposed to be a
minimal block dictating the substrate specificity of the enzymes. A new operon
type structure has been localized directly upstream from the lichenysin A
synthetase genes which, on the basis of sequence determination, potentially
encode a four-member ABC-type transport system involved in product secretion.
PMID- 9765591
TI - Poly(ADP-ribose) binding properties of histone H1 variants.
AB - Using a poly(ADP-ribose) binding assay on protein blots we examined the ability
of rat testis histone H1 variants to establish non-covalent interactions with the
polymer. All the H1 variants bound ADP-ribose polymers; the binding was salt
resistant and highly specific, occurring even in the presence of a large excess
of competitor DNA. A comparison among the H1 variants showed that H1t has the
highest affinity for poly(ADP-ribose). Long and branched poly(ADP-ribose)
molecules were found to be preferentially involved in the interaction with the
histone variants. The results further corroborate the concept that non-covalent
interactions of poly(ADP-ribose) with target proteins may constitute an important
mechanism to modulate chromatin structure.
PMID- 9765592
TI - A mutation in repB, the dictyostelium homolog of the human xeroderma pigmentosum
B gene, has increased sensitivity to UV-light but normal morphogenesis.
AB - Nucleotide excision repair (NER) is an important cellular defense mechanism which
protects the integrity of the genome by removing DNA damage caused by UV-light or
chemical agents. In humans, defects in the NER pathway result in the disease
xeroderma pigmentosum (XP) which is characterized by increased UV-sensitivity,
with increased propensity for skin cancer, and an array of developmental
abnormalities. Some XP patients exhibit, in addition, symptoms of Cockayne's
syndrome (CS) and trichothiodystrophy (TTD), which are characterized by increased
UV-sensitivity, without increased cancer incidence, and an array of developmental
abnormalities. Some NER genes, including the DNA helicases XPB and XPD, have been
shown to function in transcription as well as repair, by virtue of being an
integral part of the transcription initiation factor TFIIH. This dual function
may account for the above-mentioned wide pleiotropy of phenotypes associated with
defects in NER genes, and may explain why some XP patients exhibit developmental
abnormalities in addition to XP symptoms. To date, only five XPB patients with
three different mutations in the XPB gene have been reported. One of these
mutations is a C to A transversion at the splice site at the beginning of the
last exon, which resulted in a frameshift throughout the last exon. This patient
shows combined clinical symptoms of XP and CS. The recent cloning of the repB
gene, the Dictyostelium discoideum homolog of XPB, allowed us to generate a
similar C-terminal mutation in the Dictyostelium, in order to test whether the
defect in this NER gene has an effect on growth or development. To this end, we
have constructed a C-terminal deletion repB mutant in Dictyostelium. To avoid the
possibility that a null mutant would be lethal, we used direct homologous
recombination to create a 46 amino acid C-terminal deletion mutant. Indeed, we
were unable to obtain mutants with a longer 95 amino acid deletion. The repB
delta C46 mutants showed an increased sensitivity to UV-light, but a normal
pattern of UV-induced expression of repair genes, and no immediately obvious
defect in either growth rate or development. The results suggest that the
associated developmental defects in the human XPB patients may be due to
mutations in another gene.
PMID- 9765593
TI - Cloning, expression, characterization and role of the leader sequence of a lipase
from Rhizopus oryzae.
AB - A lipase from Rhizopus oryzae DSM 853 (ROL) was cloned from a chromosomal gene
bank, sequenced and overexpressed in Escherichia coli. ROL and its precursors
ProROL and PreProROL were purified and their pH and temperature profile was
determined. In contrast to ROL, ProROL and PreProROL had considerably higher
thermostability and a slightly higher pH optimum. Moreover, it could be
demonstrated by in vitro experiments that the natural leader sequence of ROL is
able to inhibit the folding supporting properties of the prosequence, resulting
in a retardation of folding. In addition, there is strong evidence that all
different lipase forms derived from Rhizopus sp. described in the literature are
a result of different proteolytic processing and originate from the same gene.
PMID- 9765594
TI - Binding and activation of the human aldehyde dehydrogenase 2 promoter by
hepatocyte nuclear factor 4.
AB - Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is expressed in a tissue-specific
fashion with high levels in liver, heart, kidney, and muscle, and low levels in
most other tissues. The ALDH2 promoter was found to bind nuclear proteins at a
pair of adjacent sites approximately 300 bp upstream from the translation start
site, each of which was contacted at motifs containing the hexamer A/GGGTCA. The
3' site was shown to bind in vitro translated HNF-4. It was also shown by
electrophoretic mobility shift assay utilizing antibodies against nuclear factors
and rat liver nuclear extracts to be bound by hepatocyte nuclear factor 4 (HNF
4), chicken ovalbumin upstream promoter transcription factor I and II, and
retinoid X receptors. A reporter construct containing four copies of this
promoter element was activated by co-transfection of an HNF-4 expression plasmid
in COS-1 and hepatoma cell lines. These results suggest that the tissue
specificity of ALDH2 expression is in part determined by its activation by HNF-4.
PMID- 9765595
TI - Identification and characterization of the human adipocyte apM-1 promoter.
AB - The human adipocyte-specific apM-1 gene encodes a secretory protein of the
adipose tissue and seems to play a role in the pathogenesis of obesity. A 1.3 kb
amount of the proximal promoter region has been cloned and analyzed for the
presence of putative transcription factor binding sites. Several binding sites
known to be involved in adipogenesis and regulation of adipocyte-specific genes
(C/EBP, SREBP) are present. No TATA box, but a classical CCAAT box could be
identified. To confirm functionality and cell specificity of the 1.3 kb promoter,
a series of 5'-deleted fragments were ligated in front of the luciferase gene and
the constructs were transfected into 3T3-L1 adipocytes. The reporter gene was
effectively transcribed, as demonstrated by the expression of enzyme activity.
The 5'-end of the human cDNA was completed by 5'-RACE-PCR. Several alternative
transcription start sites were detected by RNase protection assay and primer
extension analysis. In addition, an exon/intron boundary was mapped at the
extreme 5'-end of the cDNA sequence. Genomic Southern blotting suggests that the
human apM-1 gene is a single copy gene.
PMID- 9765596
TI - Sequence and expression levels in human tissues of a new member of the aldo-keto
reductase family.
AB - We have isolated a human cDNA clone from small intestine that represents a new
member of the aldo-keto reductase family. This new member showed 70% identity at
the protein level to human aldose reductase and around 80% identity to other
Chinese hamster and mouse reductases. The expression pattern shows that this
message is located primarily in the adrenal gland, thus suggesting an involvement
in steroid metabolism. It is also strongly expressed in the intestinal tract and
has been called human small intestine reductase.
PMID- 9765597
TI - The homeobox gene NTH23 of tobacco is expressed in the basal region of leaf
primordia.
AB - We reported isolation and characterization of a homeobox gene from tobacco,
NTH23. The homeodomain structure of NTH23 was highly homologous to the same
regions of class 2 genes of the KN1-type homeobox (sharing more than 85% amino
acid identity), but was less similar to class 1 genes of KN1-type. RNA gel blot
analysis revealed that NTH23 was expressed in all organs we tested although the
gene is primarily expressed in young leaves. To determine more precisely the
spatial expression pattern of NTH23 in tobacco, a chimeric NTH23::GUS fusion gene
was introduced into tobacco. The signal of GUS activity was observed at the basal
part of leaf blade primordia in the NTH23::GUS transgenic tobacco plants. This
observation suggests the possibility that NTH23 may be important for the lateral
growth of leaf blades.
PMID- 9765598
TI - Human MAFA has alternatively spliced variants.
AB - Human mast cell function-associated antigen (MAFA) cDNA has been cloned. This
molecule is similar to the rat form having an intracellular domain containing a
putative immunoreceptor tyrosine inhibition motif and an extracellular C type
lectin-like domain. However, in contrast to rat MAFA, the amino acid sequence
suggests the presence of two additional extracellular N-linked glycosylation
sites. In addition, alternative mRNA transcripts are observed that differ
substantially from those found in the rat.
PMID- 9765599
TI - Molecular cloning and characterization of the Plasmodium falciparum cytidine
triphosphate synthetase gene.
AB - Using degenerate oligonucleotides derived from conserved amino acid regions of
cytidine triphosphate synthetase, a fragment of the gene from the malarial
parasite, Plasmodium falciparum, was isolated by polymerase chain reaction (PCR).
This fragment was used as a probe in the isolation of genomic clones containing
the entire pfCTP synthetase coding region (2580 bp). The gene encodes the largest
CTP synthetase found in any organism to date due to the presence of two
additional sequences which are part of the continuous open reading frame and are
not introns as their presence in the mRNA was confirmed by reverse transcriptase
PCR. These features distinguish the parasite enzyme from that of the host making
it an attractive target for structure based drug design.
PMID- 9765600
TI - Cloning of the cDNA for glutamyl-tRNA synthetase from Arabidopsis thaliana.
AB - We cloned and characterized a full-length cDNA that encodes a glutamyl-tRNA
synthetase (GluRSAt) from Arabidopsis. The GluRSAt is coded by a single gene. A
transcript of about 2.3 kb hybridized with the cDNA. The deduced protein from the
cDNA contained 719 amino acids with an estimated molecular mass of 81 kDa.
Expression of the GluRSAt in E. coli resulted in a protein of the expected size.
Comparison of the amino acid sequence GluRSAt to other glutamyl-tRNA synthetases
showed strong sequence similarity to cytoplasmic GluRS proteins.
PMID- 9765601
TI - cDNA cloning and expression of a novel serine protease, TLSP.
AB - A cDNA for a putative novel serine protease, TLSP, was cloned from human
hippocampus cDNA with polymerase chain reaction based strategies. The putative
amino acid sequence of TLSP is similar to the trypsin-type serine proteases. TLSP
mRNA is expressed in keratinocytes. Overexpressed TLSP protein in neuro2a cells
was detected in culture medium.
PMID- 9765604
TI - [AIDS drug in the correct form].
PMID- 9765603
TI - Cloning of a novel testis specific protein serine/threonine phosphatase, PPN 58A,
from Drosophila melanogaster.
AB - A gene encoding a novel member of the PPP family of protein serine/threonine
phosphatases, termed PPN 58A, was cloned from Drosophila melanogaster. The
deduced amino acid sequence of PPN 58A exhibits 59-62% identity to D.
melanogaster PP1 isoforms, 51% identity to D. melanogaster PPY 55A and < or = 40%
identity to other members of the PPP family. The single copy gene PPN 58A maps to
chromosome 2 locus 58A. Analysis of PPN 58A mRNA reveals that, like PPY 55A, PPN
58A is a testis specific enzyme.
PMID- 9765602
TI - Four distinct regions in the auxiliary domain of heterogeneous nuclear
ribonucleoprotein C-related proteins.
AB - A 306 amino acid sequence deduced from a rabbit bladder cDNA is 98% identical to
the human heterogeneous nuclear ribonucleoprotein (hnRNP) C2. The sequence
comparison of the hnRNP C-related proteins reveals four distinct regions in the C
terminal auxiliary domain. The region next to the N-terminal RNA-binding domain
is variable in length. Following the variable region, a basic region and a
leucine zipper are conserved in all hnRNP C-related proteins including mouse and
human Raly. Several Lys-Ser-Gly repeats are present in the basic region of the
hnRNP C proteins. The C-terminal region is more divergent between hnRNP C and
Raly. Signature sequences and possible functions are proposed for the different
regions of the hnRNP C proteins.
PMID- 9765605
TI - [International interhospital transfer by scheduled airline].
AB - BACKGROUND AND OBJECTIVE: International long-distance travel increasingly takes
elderly and sometimes already ill persons to foreign countries. In case of
illness it is usually best, for both medical and social reasons, that the person
return home. This study was undertaken to assess possibilities and limits of
bringing such patients home by scheduled airline. PATIENT AND METHODS: The
transportation reports and case notes of 95 patients who had been repatriated to
Germany in 1995 and 1996 for medical reasons were analysed retrospectively. The
mean age was 56 (16-94) years. 50% of the patients had medical, 23% surgical, 19%
neurological and 8% psychiatric illnesses. RESULTS: None of the patients died
during transport. The NACA score (National Advisory Committee for Aeronautics,
USA) for determining the degree of severity of an illness (point scale 1-7) in
this group of patients was between 1 and 4, median of 3. Five patients with a
score of 5 or higher were judged not to be fit for transport. Two were
repatriated by ambulance plane, in three transport was postponed by a few days.
No invasive procedures, other than providing intravenous access, were necessary.
CONCLUSIONS: Patients who fall ill abroad can be safely and carefully brought
home by scheduled airliner over great distances without additional risk caused by
the transport. Ambulance planes are needed only in illnesses with an NACA score
of 4 or higher.
PMID- 9765606
TI - [Angina pectoris in "coronary steal syndrome" caused by a coronary fistula in the
left ventricle].
AB - HISTORY AND CLINICAL FINDINGS: A 55-year-old female patient reported left-sided
chest pain at rest as well as during exercise, which recurred during the last
three years before admission. Cardiovascular risk factors included
hypercholesterolemia and smoking. The physical examination of the patient was
unremarkable. INVESTIGATIONS: The ECG at rest showed T-wave inversions in leads
I, aVL, V3-V6 and ergometric exercise testing resulted in angina pectoris and
descending ST-segments in leads V3-V6. Stress thallium 201 scintigraphy
demonstrated a reversible perfusion deficit of the the anterior wall at peak
exercise. The left ventricular angiogram and echocardiogram revealed normal end
diastolic dimensions and regular systolic contractions without signs of left
ventricular hypertrophy. Selective coronary arteriography excluded
hemodynamically relevant stenosis of the coronary arteries. A coronary artery
fistula originating from a large, ectatic first diagonal branch with drainage
into the left ventricle was observed. TREATMENT AND COURSE: Because the patient
rejected interventional therapy she was treated conservatively and follow-up
investigations 3 and 4 years after arteriography revealed unchanged clinical
symptomatology. CONCLUSION: In this case a "coronary steal" phenomenon caused by
the coronary fistula induced myocardial ischemia. Therefore if present congenital
coronary anomalies have to be considered in patients with chest pain and normal
coronary angiogram.
PMID- 9765607
TI - [Meningeal irritation--a complication of herpes zoster].
AB - HISTORY AND CLINICAL FINDINGS: A previously healthy 26-year-old man complained of
gradually increasing headache after an attack of flu. After 4 days an erythema
with papules but no blisters was noted in the area of distribution of the left
10th thoracic nerve. As a child he had varicella (chickenpox) without
complications. INVESTIGATIONS: Lymphocytic pleocytosis and evidence of an
abnormal blood-brain barrier were noted in cerebrospinal fluid (CSF). Serology
for varicella zoster virus revealed an IgG titre of > 7400 IU/l in serum and 21
IU/l in CSF. The corresponding IgM titres were negative. TREATMENT AND COURSE:
The headaches and cutaneous changes regressed under i.v. treatment with
acyclovir, 10 mg/kg body weight, 3 x daily for 10 days. Repeat CSF examination
after 10 days showed merely minimal residual changes of inflammation. CONCLUSION:
This case illustrates the risk of severe neurological complications of herpes
zoster infection. A seemingly minor rash with headache must be correctly
diagnosed and immediate high-dosage acyclovir treatment instituted to prevent
life-threatening and severe complications of herpes zoster meningitis or
encephalitis.
PMID- 9765608
TI - [Therapy of vertigo].
PMID- 9765609
TI - [Ten years of coronary stenting--current status and perspectives].
PMID- 9765610
TI - [Longterm manometry in patients with chest pain of undetermined cause. Which
parameters should be evaluated and why?].
PMID- 9765611
TI - [Diagnosis of chronic hepatitis].
PMID- 9765612
TI - [The path to "Doctor of Medicine"--how do doctoral candidates evaluate their
dissertation?].
PMID- 9765613
TI - Mortality and cancer incidence in Misasa, Japan, a spa area with elevated radon
levels.
AB - A historical cohort study was conducted in Misasa town, Tottori prefecture,
Japan, where radon spas have been operating for a long time. Misasa town was
divided into an elevated radon level area and a control area, with mean indoor
radon levels of about 60 and 20 Bq/m3, respectively. In total, 3,083 subjects in
the elevated radon level area and 1,248 in the control area, all aged 40 or older
on January 1, 1976, were followed up until December 31, 1993, for a mean period
of 14 years. The mortality rates from all causes exhibited no difference between
the elevated radon level area and the control area for both sexes. No difference
was observed in the incidence of all-site cancers (age, period-adjusted rate
ratios by Poisson regression, RR = 1.06, 95% confidence interval (CI) 0.79-1.42
for males, RR = 0.90, 95% CI 0.65-1.24 for females), while stomach cancer
incidence seemed to decrease for both sexes (RR = 0.70, 95% CI 0.44-1.11 for
male, RR = 0.58, 95% CI 0.34-1.00 for female) and lung cancer incidence for males
only seemed to increase (RR = 1.65, 95% CI 0.83-3.30 for male, RR = 1.07, 95% CI
0.28-4.14 for female) in the elevated radon level area. Caution is needed in the
interpretation of these findings, however, since the individual exposure level
was not measured and major confounding factors, such as smoking and diet, could
not be controlled in this study.
PMID- 9765614
TI - Human T-lymphotropic virus type-I infection, antibody titers and cause-specific
mortality among atomic-bomb survivors.
AB - There have been few longitudinal studies on the long-term health effects of human
T-lymphotropic virus type-I (HTLV-I) infection. The authors performed a cohort
study of HTLV-I infection and cause-specific mortality in 3,090 atomic-bomb
survivors in Nagasaki, Japan, who were followed from 1985-1987 to 1995. The
prevalence of HTLV-I seropositivity in men and women was 99/1,196 (8.3%) and
171/1,894 (9.0%), respectively. During a median follow-up of 8.9 years, 448
deaths occurred. There was one nonfatal case of adult T-cell leukemia/lymphoma
(incidence rate = 0.46 cases/1,000 person-years; 95% confidence interval [CI]
0.01-2.6). After adjustment for sex, age and other potential confounders,
significantly increased risk among HTLV-I carriers was observed for deaths from
all causes (rate ratio [RR] = 1.41), all cancers (RR = 1.64), liver cancer (RR =
3.04), and heart diseases (RR = 2.22). The association of anti-HTLV-I
seropositivity with mortality from all non-neoplastic diseases (RR = 1.40) and
chronic liver diseases (RR = 5.03) was of borderline significance. Possible
confounding by blood transfusions and hepatitis C/B (HCV/HBV) viral infections
could not be precluded in this study. However, even after liver cancer and
chronic liver diseases were excluded, mortality rate was still increased among
HTLV-I carriers (RR = 1.32, 95% CI 0.99-1.78), especially among those with high
antibody titers (RR = 1.56, 95% CI 0.99-2.46, P for trend = 0.04). These findings
may support the idea that HTLV-I infection exerts adverse effects on mortality
from causes other than adult T-cell leukemia/lymphoma. Further studies on
confounding by HCV/HBV infections and the interaction between HCV/HBV and HTLV-I
may be required to analyze the increased mortality from liver cancer and chronic
liver diseases.
PMID- 9765615
TI - Different responses other than the formation of DNA-adducts between the livers of
carcinogen-resistant rats (DRH) and carcinogen-sensitive rats (Donryu) to 3'
methyl-4-dimethylaminoazobenzene administration.
AB - Carcinogen-resistant inbred DRH rats developed from the Donryu strain showed a
remarkably low incidence of liver tumors when they were fed diets containing
hepatocarcinogens such as 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). In
this work, we examined various characteristics of male DRH and Donryu rats during
3'-Me-DAB administration for 8 weeks. 32P-Postlabeling analysis showed that
essentially similar levels of DNA-adducts were generated by the metabolites of 3'
Me-DAB in the livers of these two strains of rats at several time points.
However, both GADD45 (growth arrest and DNA damage-inducible) and O6
methylguanine methyltransferase (putatively DNA damage-inducible) mRNA levels
were increased significantly in Donryu rat livers, but were increased to a lesser
extent in DRH rats. [3H]Thymidine incorporation into hepatic DNA began to
increase around 10 to 20 days after the start of 3'-Me-DAB administration in
Donryu rats probably due to DNA repair, while no significant change occurred in
DRH rats under the same conditions. Furthermore, inductions of heme oxygenase
(due to degradation of heme-proteins) and hepatocyte growth factor (HGF; cell
death and regeneration of hepatocytes) mRNAs were greater in Donryu rat livers
than those of DRH, suggesting that the former were more sensitive to cytotoxic
effects of 3'-Me-DAB than the latter. Another remarkable difference observed
between these two strains was the significant induction of cytochrome P-450 2E1
mRNA in Donryu rat livers; this may contribute to the generation of reactive
oxygen intermediates. Finally, increases of glutathione S-transferase (P-form)
and gamma-glutamyltranspeptidase mRNAs as marker enzymes of preneoplastic changes
of hepatocytes were clearly seen only in Donryu rat livers at 6 to 8 weeks after
the start of 3'-Me-DAB administration. These results indicate that the different
susceptibility to hepatocarcinogenesis between these two strains of rats may
arise from events other than the DNA adduct formation.
PMID- 9765617
TI - Mutation analysis of the WT1 gene in myelodysplastic syndromes.
AB - The WT1 tumor suppressor gene was examined for mutations in a panel of 44
patients with myelodysplastic syndromes (MDS) including acute myelogenous
leukemias (AML) secondary to MDS, using polymerase chain reaction single-strand
conformation polymorphism (PCR-SSCP) analysis and sequencing analysis. A WT1
mutation was detected in one out of 17 cases of AML secondary to MDS. This
mutation exists upstream of the zinc finger region and is predicted to produce a
truncated WT1 protein lacking the zinc finger region. No mutations were detected
in 27 MDS patients who had not progressed to AML. This is the first report of
analysis for WT1 mutations in a large number of MDS patients, suggesting that WT1
mutations are uncommon in MDS. Abnormalities in this gene may, however,
contribute to a small proportion of cases showing progression from MDS into AML.
PMID- 9765616
TI - Development of high-grade renal cell carcinomas in rats independently of somatic
mutations in the Tsc2 and VHL tumor suppressor genes.
AB - Ferric nitrilotriacetate (Fe-NTA) induces renal proximal tubular damage that
ultimately leads to a high incidence of renal cell carcinoma (RCC) in rats. The
RCCs are characterized by 1) high incidence of pulmonary metastasis and
peritoneal invasion, 2) high incidence of tumor-associated mortality and 3)
possible involvement of reactive oxygen species in carcinogenesis. The present
study investigated the possible role of Tsc2 and VHL tumor suppressor genes in
this model. Thirty-four Fe-NTA-induced primary RCCs and 20 other primary or
metastatic tumors of rats were searched for genetic alteration in all the coding
exons of both genes by polymerase chain reaction-single-strand-conformation
polymorphism analysis and sequencing in conjunction with morphological
evaluation. In the Fe-NTA-induced RCCs, frequency of metastasis or invasion was
proportionally associated with the nuclear grade of the tumor (grades 1-3). Only
one Fe-NTA-induced RCC of grade 1 revealed missense mutations with loss of
heterozygosity in exon 10 of the Tsc2 gene (codons 334, GTG (Val) to GCG (Ala),
and 336, TAT (Tyr) to CAT (His). No mutation was found in the VHL gene. The
results suggest that 1) high-grade RCCs can develop in the absence of mutations
in the Tsc2 and VHL genes in rats, and that 2) Tsc2 gene somatic mutation can
nonetheless be one of the causes of non-Eker rat RCCs.
PMID- 9765618
TI - Infrequent mutations of the hOGG1 gene, that is involved in the excision of 8
hydroxyguanine in damaged DNA, in human gastric cancer.
AB - DNA glycosylase, encoded by the hOGG1 gene, repairs 8-hydroxyguanine (oh8Gua),
which is an oxidatively damaged mutagenic base. To clarify whether the DNA repair
activity of hOGG1 protein is involved in gastric carcinogenesis, we examined 9
gastric cancer cell lines and 35 primary gastric cancers for mutations and
genetic polymorphisms of the hOGG1 gene by polymerase chain reaction-single
strand conformation polymorphism analysis. A G-to-A transition was detected in a
gastric cancer cell line, MKN1. This nucleotide change caused the conversion of
the amino acid from Arg to His at codon 154, which is located in a domain highly
conserved among human, mouse, and yeast OGG1 proteins. No mutation was detected
in primary gastric cancers. We compared the distribution of the polymorphic
alleles associated with enzymatic activity (hOGG1-Ser326 vs. hOGG1-Cys326)
between 35 gastric cancer patients and 42 healthy individuals. Although the
frequency of the Cys326 allele, associated with low enzymatic activity, in
gastric cancer patients was a little higher than that in healthy individuals, the
difference did not reach statistical significance. These results suggest that low
hOGG1 activity due to mutations and genetic polymorphisms is involved in the
development of only a small subset of gastric cancers.
PMID- 9765619
TI - Expression of cadherin-catenin cell adhesion molecules, phosphorylated tyrosine
residues and growth factor receptor-tyrosine kinases in gastric cancers.
AB - Tyrosine phosphorylation of beta-catenin, an intracytoplasmic E-cadherin-binding
protein, has been shown to disrupt the cadherin-mediated cell adhesion system in
vitro. In order to investigate the relationships of expression and tyrosine
phosphorylation of cadherin-catenin molecules and expression of growth factor
receptor-tyrosine kinase with loose cell-to-cell adhesion, immunohistochemical
staining for E-cadherin, alpha- and beta-catenin, phosphorylated tyrosine
residues and tyrosine kinase receptors, including c-erbB-2, epidermal growth
factor-receptor (EGF-R), c-met and K-sam, in 17 undifferentiated- and 10
differentiated-type human gastric cancers was performed. Loss or reduced
expressions of E-cadherin and alpha- and beta-catenin (11, 11, 10 cancers,
respectively) were observed in the former, but not the latter. Diffuse
cytoplasmic staining of E-cadherin, alpha- and beta-catenin and phosphotyrosine
residues was observed frequently in the undifferentiated-type cancers. The
cytoplasmic localization of phosphotyrosine residues in undifferentiated-type
cancers was correlated significantly with K-sam expression (P < 0.01) and diffuse
cytoplasmic staining of E-cadherin (P < 0.05) and beta-catenin (P < 0.05).
Expression of K-sam protein was detected significantly more frequently in
undifferentiated- (6/17; P < 0.05) than differentiated-type adenocarcinomas
whereas the converse applied to c-erbB-2 expression (8/10 of the latter, P <
0.05). Tyrosine phosphorylation of beta-catenin was directly confirmed in the
protein extracts of one undifferentiated-type gastric cancer. These data indicate
that alteration of tyrosine phosphorylation status associated with K-sam
expression may cause the cytoplasmic distribution of cadherin-catenin molecules
and loose cell-cell adhesion in undifferentiated-type gastric cancers.
PMID- 9765620
TI - Nonsense mutation at codon 63 of the BRCA1 gene in Japanese breast cancer
patients.
AB - The involvement of abnormalities of the BRCA1 gene in breast cancers in Japanese
patients without any family history of this cancer was investigated by polymerase
chain reaction-based single-strand conformation polymorphism analysis of the DNA
sequences corresponding to the zinc finger domain (exons 2, 3 and 5) and the
binding domain with Rad51 (exon 11) of the BRCA1 protein. An identical nonsense
mutation at codon 63 (TTA to TAA) was found in 2 of 56 (3.5%) breast cancers from
independent patients. The nucleotide change was also detected in the DNAs from
non-cancerous tissues of both patients and therefore was a germline mutation. One
of the patients was a member of a pedigree involving 3 ovarian cancer and 1
gastric cancer patients, while the other patient had no family history of
malignancy. The same germline mutation at codon 63 was reported in four other
independent Japanese pedigrees with frequent breast cancer, but not in such
families in other countries. These observations suggest that the mutation
commonly originated from a single Japanese ancestor. No other mutation of the
BRCA1 gene was observed in the samples analyzed in this study. A low incidence of
germline mutation and the absence of somatic mutation suggest that the aberration
of the BRCA1 gene is involved only in a subset of Japanese breast cancers.
PMID- 9765621
TI - Somatic mutations of the PTEN/MMAC1 gene in fifteen Japanese endometrial cancers:
evidence for inactivation of both alleles.
AB - Loss of heterozygosity (LOH) of chromosome 10q is observed in approximately 40%
of endometrial cancers. Mutations in PTEN/MMAC1, a gene recently isolated from
the 10q23 region, are responsible for two dominantly inherited neoplastic
syndromes, Cowden disease and Bannayan-Zonana syndrome. Somatic mutations of this
gene have also been detected in sporadic cancers of the brain, prostate and
breast. To investigate the potential role of this putative tumor suppressor gene
in endometrial carcinogenesis as well, we examined 46 primary endometrial cancers
for LOH at the 10q23 region, and for mutations in the entire coding region and
exon-intron boundaries of the PTEN/MMAC1 gene. LOH was identified in half of the
38 informative cases, and subtle somatic mutations were detected in 15 tumors
(33%). Our results suggest that of the genes studied so far in endometrial
carcinomas, PTEN/MMAC1 is the most commonly mutated one, and that inactivation of
both copies by allelic loss and/or mutation, a pattern that defines genes as
"tumor suppressors," contributes to tumorigenesis in endometrial cancers.
PMID- 9765622
TI - Sequence analysis of genes encoding rodent homologues of the human tumor
rejection antigen SART-1.
AB - Human SART-1 (hSART-1) gene encodes a 125 kD protein with a leucine-zipper motif
expressed in the nucleus of all proliferating cells, and a 43 kD protein
expressed in the cytosol of most epithelial cancers. In this study, two rodent
genes (rSART-1 and mSART-1) homologous to hSART-1 were cloned from cDNA libraries
of murine brain and a rat tumor cell line, respectively. mSART-1 and rSART-1 were
highly homologous to hSART-1 with 86% and 84% identity at the nucleotide level,
and 95% and 91% at the protein level, respectively. The leucine zipper domain and
two basic amino acid portions that bind DNA, as well as peptide sequences
recognized by human cytotoxic T lymphocytes (CTLs), were all conserved in these
rodent genes. Nuclear protein homologous to the 125 kD hSART-1(800) protein, but
not to the 43 kD cytosol SART-1(259) protein, was detectable with specific
antibody in the nuclear fractions of rodent tumor cell lines, and normal rodent
fetal liver and testis. These rodent genes should be a novel tool for studies on
the biological roles of the SART-1 gene, and also in the construction of animal
models of specific immunotherapy using SART-1 gene products.
PMID- 9765623
TI - Differential expression of DNA topoisomerase II alpha and II beta genes between
small cell and non-small cell lung cancer.
AB - DNA topoisomerase II (Topo II) inhibitors are widely used in lung cancer
chemotherapy, but small cell lung cancer (SCLC) and non-small cell lung cancer
(NSCLC) show different sensitivity to them. In this study, we examined the gene
expression levels of both isoforms of Topo II (II alpha and II beta) in lung
cancer specimens to investigate the differential expression between SCLC and
NSCLC. The expression levels of the Topo II alpha and Topo II beta genes were
assessed in 80 autopsy samples (40 primary tumors and 40 corresponding normal
lung tissues) by using the reverse transcription polymerase chain reaction. We
found that the expression levels of the Topo II alpha gene in tumors were
significantly higher than those in normal lung tissues, and that those in SCLC
were significantly higher than those in NSCLC. There were no significant
differences in Topo II beta gene expression between tumors and normal lung
tissues and between SCLC and NSCLC. Further-more, correlation analysis revealed
that Topo II alpha expression was correlated with Topo II beta expression in both
tumor and normal lung tissues. These results indicate that a difference exists in
the regulation of the Topo II gene between lung tumors and normal lung tissues.
Our finding of differential expression of Topo II alpha between SCLC and NSCLC
also suggests that the Topo II alpha expression level is associated with
sensitivity to Topo II inhibitors.
PMID- 9765624
TI - The TdT-mediated dUTP nick end labeling assay precisely assesses the DNA damage
in human tumor xenografts.
AB - Cultured HL-60, HeLa S3 and WiDr cells grown in male BALB/c nu/nu mice were
studied by conventional and field-inversion DNA gel electrophoresis (FIGE), as
well as by means of cytomorphological approaches, including TdT-mediated dUTP
nick end labeling (TUNEL) assay. Chemosensitivity tests revealed HL-60 to be
sensitive to vindesine (VDS), and HeLa S3 and WiDr to mitomycin C (MMC). Although
VDS-treated HL-60 exhibited condensation of chromatin and a DNA ladder, MMC
exposed HL-60 cells showed apoptotic figures without typical DNA ladders. With
MMC-treated WiDr cells, neither DNA ladders nor apoptotic figures were observed.
Cells characterized by chromatin condensation were TUNEL-positive in both treated
and untreated cases with the exception of the MMC-treated WiDr case, in which
many TUNEL-positive cells were observed without cytomorphological changes. On
FIGE, DNA fragments of approximately 50, 300 and 400 kbp were detected in groups
treated with both effective and ineffective drugs, as well as in untreated
controls. Furthermore, change of the time parameters in FIGE resulted in
different sizes (550 and 850 kbp) of DNA fragments. These findings indicate that
i) cell death is not always detectable in terms of apoptotic figures or DNA
oligonucleosomal fragmentation, ii) only the TUNEL assay is a reliable tool to
detect DNA damage and, iii) FIGE does not provide accurate size profiles of
macromolecular DNA fragments.
PMID- 9765626
TI - Renal tumours: the new order.
PMID- 9765625
TI - Rhenium-186-mercaptoacetyltriglycine-labeled monoclonal antibody for
radioimmunotherapy: in vitro assessment, in vivo kinetics and dosimetry in tumor
bearing nude mice.
AB - Stability and immunoreactivity of 186Re-labeled monoclonal antibody were
examined, and its in vivo kinetics was investigated in tumor-bearing Balb/c nu/nu
female mice to assess the feasibility of using it in radioimmunotherapy (RIT). A
murine IgG1, A7, against a 45 kD glycoprotein in human colon cancer was
radiolabeled with 186Re by using a chelating method with a
mercaptoacetyltriglycine (MAG3). 186Re-MAG3 complex was conjugated to A7 after
esterification of 186Re-MAG3 with tetrafluorophenol (TFP). The efficiency of
186Re-MAG3-TFP production and the labeling efficiency of A7 were 51-59% and 57
60%, respectively. Immunoreactivity of purified 186Re-MAG3-A7 was 68.2% at
infinite antigen excess. In 0.9% NaCl at 4 degrees C, the radioactivity (12.7
MBq/mg, 3.55 MBq/ml) dissociated with time from 186Re-MAG3-A7 as a small
molecular weight moiety because of autoradiolysis. The addition of ascorbic acid,
5 mg/ml, as a radioprotectant or storage at -80 degrees C could effectively
prevent the radiolysis of 186Re-MAG3-A7 for 7 days. Immunoreactivity of 186Re
MAG3-A7, 6.70 MBq/mg (6.66 MBq/ml), stored in the presence of ascorbic acid was
well retained up to 8 days after the preparation. In colon cancer xenografted
mice, 31.0% of the injected dose/g of 186Re-MAG3-A7 had accumulated in the tumors
at 24 h postinjection. Estimated radiation dose to tumors was 14.9 cGy/37 kBq up
to 8 days postinjection which was 12-fold greater than the whole-body radiation
dose. These in vivo characteristics were superior to those of A7 labeled with
radioiodine, affording greater therapeutic ratios than 131I-A7. Because of the
better image quality of 186Re-MAG3-A7 as well as more favorable dosimetry, 186Re
MAG3-A7 would be a better choice for RIT of colon cancer than 131I-A7. These
results indicated the feasibility of RIT with 186Re-MAG3-A7, though the
prevention of radiolysis of the labeled antibody should be considered.
PMID- 9765627
TI - Dietary intakes of middle-aged European, Maori and Pacific Islands people living
in New Zealand.
AB - AIM: To compare dietary intakes of Maori, Pacific Islands and European men and
women in New Zealand. METHODS: A food frequency questionnaire was used to
calculate nutrient intakes of 5523 New Zealand workers aged 40 years and over
(3997 men, 1524 women) from a cross-sectional survey carried out between 1988 to
1990. RESULTS: Compared with European men and women, Maori women and Pacific
Islands men and women consumed larger amounts of total energy per day. Age
adjusted nutrients expressed as percentage contribution to total energy intakes
showed that Maori and Pacific Islands men and women consumed less carbohydrate,
fibre and calcium, and more protein, fat, saturated fat and cholesterol than
European men and women, respectively. These results were consistent with fewer
servings of cereal and cheese per month, and more servings of red meats, fish and
eggs in Maori and Pacific Islands participants compared with Europeans, after
adjusting for age and total energy intakes. Pacific Islands men and women also
consumed more servings of chicken, fewer cups of milk and fewer servings of fruit
per month compared to Europeans. Maori men and women consumed more slices of
bread and fewer servings of vegetables per month compared to European men and
women. CONCLUSIONS: There were striking differences in dietary habits, food
selections and cooking practices between European, Maori and Pacific Islands
participants. Dietary intakes of Maori workers were closer to those of Europeans
than those of Pacific Islands participants. Ethnic differences were due to larger
portion sizes and increased frequency of most foods in Maori and Pacific Islands
participants.
PMID- 9765628
TI - Are short-stay admissions to an acute general medical unit appropriate?
Wellington Hospital experience.
AB - AIM: This audit was performed to ascertain whether the admission of patients to
the General Medical Unit (Wellington Hospital) for one day or less was
appropriate. METHODS: Between 1 July 1996 and 30 June 1997, 494 patients were
admitted to General Medicine for one day or less. The medical records for a
random sample of 245 patients were reviewed. A modification of the Oxford Bed
Study Instrument was used to assess the appropriateness of admission. RESULTS:
Twenty admissions (8.2%) were deemed inappropriate, six patients could have been
referred to medical outpatients, four were known epileptics who presented
following a seizure, and none of the others merited admission on severity
criteria. Ten patients were triaged after 10.00 pm, when discharge becomes more
difficult. Forty-two patients required an investigation which delayed discharge.
CONCLUSION: With the present community and investigation facilities available,
there is no evidence that the majority of 24-hour admissions to acute General
Medicine are inappropriate.
PMID- 9765629
TI - The utility of chest radiography in the follow-up of pneumonia.
AB - AIM: We conducted this study to determine whether chest radiography was
clinically useful in the follow-up of uncomplicated pneumonia affecting children
aged between 6 weeks and 15 years. METHOD: We examined the case records of all 78
paediatric admissions for pneumonia to our hospital over one year. Thirteen
children were excluded on account of age or other complicating factors. RESULTS:
Of the 65 study cases, the mean age was 3.5 years (range 0.4-13 years). On
admission 51 (79%) had cough, 53 (82%) fever, 53 (82%) tachypnoea and 50 (77%)
had abnormal chest signs. Elevation of C reactive protein was recorded in 43
(66%) cases and leukocytosis in 42 (65%). All children received initial chest
radiographs which showed unilobular/lobar changes in 34 (53%), bilobar changes in
19 (29%) and diffuse abnormalities in 7 (11%). Forty-one patients were followed
up both clinically and radiologically, usually (31 cases) between four and six
weeks after discharge. Thirty-seven children had no abnormal symptoms or signs
and had normal chest radiographs. The remaining four had symptoms and signs,
their radiographs showed either slight resolution or no change from the admission
films. CONCLUSION: In cases of uncomplicated pneumonia, follow-up chest
radiography should be deferred until at least four weeks after discharge and is
not indicated if symptoms and signs are absent.
PMID- 9765630
TI - Creating a general practice national minimum data set: present possibility or
future plan?
AB - AIM: To assess the feasibility of implementing the recommendations of the New
Zealand National Minimum Data Set working party in computerised general
practices. METHOD: Doctors from 12 computerised general practices belonging to
the Royal New Zealand College of General Practitioners' Dunedin Research Unit
Computer Network participated in the study (five Dunedin practices, four in rural
Otago and Southland, and three in Christchurch). A three-month sample of data was
extracted from practice computers and evaluated for completeness and compliance
to the national minimum data set structure. Rates of recording practice
identifier, provider, patient identifiers, sex, ethnicity, government subsidy
eligibility, consultation identifier and date, prescriptions and Read codes were
calculated for each practice. RESULTS: Apart from data recorded automatically by
computers, there was a wide range in the extent of missing data. Of the data
requiring manual computer entry, patient demography and subsidy eligibility were
most comprehensively recorded (date of birth 99.9%, sex 99.6%, eligibility to
subsidies 98.5%). Data with little immediate clinical or management relevance
were poorly recorded (Read codes 32.4% and ethnicity 5.0%). CONCLUSIONS: It is
possible to derive a common minimum data set from different computerised general
practices. However some data elements will be missing unless suitable education
and support are provided for the doctors and other staff members who record
patient information.
PMID- 9765631
TI - Endoscopic band ligation of gastric angiodysplasia.
PMID- 9765632
TI - How accurate are New Zealand death certificates?
PMID- 9765633
TI - Monitoring clinical trials.
PMID- 9765634
TI - Youth suicide rates.
PMID- 9765635
TI - Dental amalgam.
PMID- 9765636
TI - Meningococcal disease.
PMID- 9765637
TI - Smoking kills 31% of Maori.
PMID- 9765638
TI - Possible idiosyncratic reaction to OC spray.
PMID- 9765639
TI - Sudden infant death syndrome.
PMID- 9765640
TI - Burnout in rural general practitioners.
PMID- 9765641
TI - Licensing of medical practitioners.
PMID- 9765643
TI - HIV infection in women in New Zealand.
PMID- 9765642
TI - Licensing of medical practitioners.
PMID- 9765644
TI - [Contribution of hysteroscopic surgery for the treatment of postmenopausal
metrorrhagia].
AB - OBJECTIVES: Determine the effectiveness of hysteroscopic surgery in persistent
postmenopausal bleeding. PATIENTS AND METHODS: Transcervical resection was
performed in 176 women between the ages of 46-74 years. A benign cause was noted
in 135 cases (polyps in 80 and submucous fibroids in 55); 37 patients had no
significant disease and 4 had endometrial atypical hyperplasia missed in the
preoperative evaluation. Patients underwent resection of polyp, resection of
fibroid or endometrial ablation. Major operative complications were rare and
included 3 perforations and one case of fluid overload. Patients were followed
for 1-10 years after treatment (mean follow-up 52 months). RESULTS: 167 patients
completed the study. Clinical manifestations disappeared in 85.2% of the
patients; 15 patients had hysterectomy after the hysteroscopic procedure and 11
had repeat transcervical resection. CONCLUSION: Hysteroscopic treatment can be
effective in carefully selected patients with postmenopausal bleeding or abnormal
uterine bleeding on hormone replacement therapy. The operative criteria should
take the causes of bleeding and not just the age of patient into account.
PMID- 9765645
TI - [Mixed corticomedullary tumor].
AB - BACKGROUND: Pheochromocytoma and primary hyperaldosteronism rarely occur
simultaneously. Few cases have been reported in the literature. CASE REPORT: A
patient explored for hypertension was found to have hypokalemia related to
primary hyperaldosteronism. Pathology examination of the ablated adrenal showed a
co-existing pheochromocytoma suspected at history taking although urine
catecholamines were normal. DISCUSSION: Different pathogenic hypothesis have been
proposed. Such dual tumors could be a simple coincidence, occur in a particular
genetic setting, be related to direct contact between cortical and medullary
tissue leading to reactional cortical hyperplasia, pheochromocytoma produced
factors stimulating aldosterone synthesis, or factor X, a substance produced by
cortical adenomas and favoring growth of the pheochromocytoma.
PMID- 9765646
TI - [Septic shock with coma revealing typhoid fever].
AB - BACKGROUND: Typhoid fever may be difficult to distinguish from malaria. Septic
shock, encephalopathy and leukopenia are common features of both diseases. CASE
REPORT: A 20-year-old South Korean woman was admitted to the intensive care unit
with coma and shock. Vomiting and abdominal pain were followed by headache,
prostration, fever and diarrhea. Leukocytopenia, lymphocytopenia,
thrombocytopenia, rhabdomyolysis and hepatitis were present. Clotting tests were
normal. The thick peripheral blood film was negative. Salmonella typhi was
isolated from 6 blood cultures. Treatment associated ceftriaxone 4 g per day for
5 days, colloid and crystalloid fluids and dopamine. The patient was discharged 2
weeks later. DISCUSSION: Typhoid fever should be considered as a diagnosis in
patients with sepsis who come from endemic zones. Abdominal symptoms, prolonged
fever, coma and delayed headache are particularly contributive signs. Specific
treatment should be instituted.
PMID- 9765647
TI - [Vipera ursinii poisoning: 8 cases].
PMID- 9765648
TI - [Leriche syndrome in a case of atrophic polychondritis].
PMID- 9765650
TI - [Gossypiboma: an adverse effect or the effect of English language?].
PMID- 9765649
TI - [Late colonic metastasis of renal cell cancer].
PMID- 9765651
TI - [Prevention of avoidable iatrogenic effects: the obligation for vigilance].
AB - PREVALENCE: Latrogenic-related morbidity and mortality rates are difficult to
determine. Certain estimations in France and other countries have suggested that
drug-related accidents alone could account for 5 to 10% of all acute
hospitalizations. This would mean that in France, several thousand deaths are
caused annuallty by drugs. COST CONSIDERATIONS: Independent of the human aspect,
health care expenditures related to iatrogenic accidents are substantial. In
France, the cost would be several ten billion francs. Although the cost/benefit
ratio remains highly positive, statistically speaking one cannot ignore the high
cost of severe accidents. THE NOTION OF RISK: There is an urgent need to persuade
the public opinion that all effective medicines, like all surgical procedures,
carry a risk. Zero risk does not exist. Patients, and the public in general,
should come to realize that the objective is to minimize risk inherent in all
therapies. PREVENTION: It is the duty of the entire health care team to calculate
the level of acceptable risk and take all the necessary preventive measures. One
of the objectives of the French National Educational Association for Training in
Therapeutics (APNET) is to define means of reducing latrogenic effects.
PMID- 9765652
TI - [Non-ulcerating dyspepsia: role of Helicobacter pylori].
PMID- 9765653
TI - [Role of diagnostic hysteroscopy in the exploration of postmenopausal
metrorrhagia].
AB - DIAGNOSIS: Diagnostic hysteroscopy is an effective method for identifying the
causes of postmenopausal bleeding. It evaluates the uterine cavity and visualizes
pathologic conditions such as endometrial polyps, submucous fibroids, and focal
endometrial abnormalities including adenocarcinoma and its precursors. FURTHER
INFORMATION: With directed biopsy, diagnostic hysteroscopy also ensures the
recognition of these lesions.
PMID- 9765654
TI - [Intracranial hypotension].
AB - A CLINICAL DIAGNOSIS: Headache which appears in the upright position and subsides
in the reclining position is suggestive of intracranial hypotension Brain
magnetic resonance imaging can eliminate an intracranial tumoral process. In most
cases, contrast images after gadolinium injection show a diffuse hypersignal of
all the meninges including the falx cerebri and the tentorium cerebelli.
SPONTANEOUS OR SECONDARY: This clinical presentation is sufficient for diagnosis.
Occurring after a recent neurosurgical procedure, the intracranial hypotension is
termed secondary. Inversely, is no known cause can be identified, the condition
is termed spontaneous. CEREBROSPINAL FLUID: If the clinical manifestations are
somewhat doubtful, a spinal tap can reveal the very low pressure of the
cerebrospinal fluid (CSF) although it is advisable to avoid further loss of
fluid. CSF LEAK: It is generally accepted that intracranial hypotension results
from leakages of CSF through a breach in the dura mater caused by untreated
trauma to a particularly fragile area due to a meningocele or an arachnoid cyst
for example. Occasionally, the CSF leak can be evidenced with isotopic labeling
used to visualize the breach and guide therapy. TREATMENT: By analogy with the
spinal tap syndrome, a blood-patch with autologous blood is usually proposed as
first line medical treatment. Prognosis is generally good.
PMID- 9765655
TI - [Functional manifestations of osteoarthritis: key points to the clinical efficacy
of diacerhein].
PMID- 9765656
TI - [Management of febrile episodes in neutropenic patients].
PMID- 9765657
TI - [Hirudin for heparin-induced thrombopenia: a new step forward].
PMID- 9765658
TI - [Once upon a time there was hirudin...].
PMID- 9765659
TI - [Heparin-induced thrombopenia. Clinical manifestations and physiopathology].
AB - CLINICAL SIGNS: Heparin-induced thrombocytopenia is a clinically interesting
model of immunological thrombocytopenia because thrombus formation occurs much
more frequently than hemorrhage, in some patients, major thrombocytopenia is
observed with signs of consumption coagulopathy. HIGH INCIDENCE OF THROMBUS
FORMATION: Venous thrombi predominate with severe consequences such as pulmonary
emboli or more rarely distal gangrene. Artenal thrombi are less frequent but are
highly suggestive and often lead to acute ischemia in the lower limbs.
IMMUNOLOGICAL MECHANISM: Severe forms of heparin-induced thrombocytopenia result
from an immunological mechanism and are associated with IgG antibody production.
The Fc fragment of these antibodies activate platelets. Heparin-dependent
antibodies preferentially recognize antigenic complexes formed by the heparin
platelet facto 4 association although certain other antigens (IL-8 or NAP-2 are
also recognized. Thrombus formation results from platelet activation and enhanced
coagulability which can be favored by antibody binding to endothelial cells and
synthesis of tissue factor. PRACTICAL ASPECTS: Severe heparin-induced
thrombocytopenia is particularly frequent in medical and surgical situations
involving platelet activation and treatments by infractionated heparins. No
particular phenotype of the IgG Fc receptor has been identified. Likewise no
specific risk factors have been found. As effective antithrombin therapy is
required in most cases, Xa inhibitors or thrombin inhibitors are useful.
PMID- 9765660
TI - [Biological diagnosis and surveillance of heparin-induced thrombopenia].
AB - THE CHALLENGE: Heparin-induced thrombocytopenia is a diagnostic challenge for the
clinician. Currently, it is recommended to monitor platelet counts for the first
3 weeks of heparin therapy. Laboratory counts often may drop off before any
evidence of a clinical manifestation. LABORATORY TESTS: Confirming the diagnosis
of heparin-induced thrombocytopenia's often difficult during the acute phase. The
most widely used tests evidence a platelet activator or proaggregate effect when
the patient's plasma or serum is exposed to heparin. In France, the platelet
aggregation test is used almost exclusively although release of labeled serotonin
is considered to be the reference technique. The antigenic target of antibodies
produced in heparin-induced thrombocytopenia are identified by their constituent
platelet factor 4 and heparin sulfate chains. A commercial immunological kit is
based on this principle. SUBSTITUTION TREATMENT: The laboratory's contribution
goes beyond positive diagnosis of heparin-induced thrombocytopenia. Indeed,
disseminated intravascular coagulation must be recognized and a substitution
treatment proposed together with a measuring the activated partial thromboplastia
time.
PMID- 9765661
TI - [Management of a suspicion of heparin-induced thrombopenia].
AB - A COMPLEX SITUATION: During the acute phase of heparin-induced thrombocytopenia,
the question must be raised as to whether an antithrombotic therapy is to be
continued using a compound other than heparin. Later the risk of reintroducing
heparin again can be discussed. THERAPEUTIC PROPOSITIONS: Excepting vena cava
interruption, surgical revascularization and thrombolysis, possible therapeutic
propositions can be divided into two categories; anticoagulants and related
compounds (hirudin); and oral anticoagulants (anti-vitamin K) and antiplatelet
agents (aspirin for example). Low molecular-weight heparin cannot be recommended
in 1998 in patients with heparin-induced thrombocytopenia due to standard
heparin. IN PRACTICE: Unfractionated heparin or low-molecular weight heparin must
be stopped immediately. The hematology laboratory should be consulted. It must be
remembered that prevention, based on a careful assessment of the benefit/risk
ratio when initiating heparin therapy, is essential.
PMID- 9765662
TI - [Thrombin and its pharmacologic regulation].
AB - THROMBUS FORMATION: Thrombin plays a crucial role in thrombus formation. It
transforms fibrinogen into fibrin and activates platelets. Thrombin has both
stimulating and inhibiting effects controlling the feedback regulation of
thrombus formation. Thrombin also stimulates circulating cells other than
platelets and vascular cells and thus participates in inflammation and wound
repair accompanying hemostasis and thrombosis. Thrombin's interaction with cells
is mediated by proteolysis activated receptors (PAR), mainly PAR-1 and probably
by the recently cloned PAR-3. MECHANISM OF ACTION: Thrombin is an ellipsoid
shaped serine protease whose active site is located at the bottom of a deep
groove. One end of the groove bearing the active site carries exosite 1 which
links with the C-terminal end of hirudine, PAR-1 and PAR-3, fibrinogen and
fibrin, thrombomoduline and platelet GPIb. Exosite 2 is carried on the top side
of the molecule opposite the active site. It binds to certain glycoaminoglycanes
such as heparin. Thrombin's high substrate specificity results from multiple
interactions which occur between different functional domains and complementary
domains on the substrate. ACTION OF HEPARIN: The antithrombotic effect of heparin
results from its catalytic effect on antithrombin III (AT) inhibition of
thrombin. This effect is however limited because heparin is dependent on the
concentration of AT and on the of inactivating proteins such as platelet factor
4. In addition, the inhibitory effect of the AT-heparin complex is limited for
thrombin bound to the thrombus. Finally, heparin can produce a rare but severe
complication, heparin-induced thrombocytopenia. Because of these different
drawbacks, research has been focused on other thrombin inhibitors. DIRECT
THROMBIN INHIBITORS: The target of these inhibitors is the active site of
thrombin. Many compounds are under study, including several which can be
administrated orally. The most advanced clinical trials have been conducted with
hirudin. Hirudin binds to thrombin at several sites, blocking all the known
functions of thrombin. The problem of choosing an agent to maintain antithombotic
therapy in patients with heparin-induced thrombocytopenia remains unresolved.
Hirudin would be a likely choice as it has no cross reactivity with heparin or
heparinoids. Promising early results have been reported.
PMID- 9765663
TI - [Refludan. First line of treatment for type II heparin-induced thrombopenia].
AB - OBJECTIVES: To assess morbidity and mortality in patients treated with Refludan
for heparin-induced thrombocytopenia type II in comparison with controls.
PATIENTS AND METHODS: One hundred thirteen patients with heparin-induced
thrombocytopenia were treated with Refludan in two studies, HAT1 and HAT2.
Clinical outcome was assessed in a meta analysis and compared to results in 91
control patients from a former series. Patients with no associated thrombolytic
treatment were given an intravenous bolus injection of Refludan (0.4 mg/kg) then
a continuous infusion of Refuldan (0.15 mg/kg/h). When a thrombolytic treatment
was associated, patient were given a 0.2 mg/kg) bolus followed by a 0.10 mg/kg/h
infusion. RESULTS: The rate of thromboembolism complications, amputations and
death was significantly lower in patients treated with Refludan than in controls.
There was a clinically acceptable increase in episodes of bleeding with Refludan.
The benefit/risk ratio was optimum for APTT between 1.5 and 3.
PMID- 9765664
TI - [Refludan: pharmacologic surveillance study].
PMID- 9765665
TI - [Effect of prenatal irradiation of rats on morphofunctional state of progeny
testis].
AB - It was studied the morphofunctional state of rats testes at the age of 7, 9 and
19 weeks, which has been developed from embryos gamma-irradiated at dose 1,0 Gy
during organogenesis (on the 15th day of pregnancy). The analyse of testes
weight, total content of spermatogenic cells and amount of spermatozoa, RNA and
DNA content in testicular tissue in prepubertal and pubertal rats irradiated in
utero at low dose indicates radiation effects in reproductive system, which are
preserved in postnatal period of animals life for a long time.
PMID- 9765666
TI - [Proteins induction by cysteamine in Escherichia coli cells].
AB - It was shown, what in presence of oxygen in broad interval time of treatment in
E. coli cells was induced line proteins by cysteamine which are proteins SOS-
repair system and heat--shock system. There are quantitative defined induction
level RecA, GroEL and DnaK proteins which are members this systems. It was
allowed to propose what radioprotective action of cysteamine in higher degree is
defined by its characteristics as induction agent for stress systems of cells.
PMID- 9765667
TI - [Quantitative analysis of inducible systems of Escherichia coli and Bacillus
subtilis using radioimmunological methods].
AB - By RIA dot-blot method two main cell system, system SOS-repair and heat shock
system, was showed possibility to receive as well qualitative as quantitative
results influence of different induced agents. Was showed quantitative
differences in initial levels enzymes of RecA and CroEL in different strains of
E. coli, as well of principle possibility to using received antibody, which has
high specific to this enzymes, for investigation reactions this systems in the
other bacterial species, such as Bac. subtilis.
PMID- 9765668
TI - [Aorta dilatation after prolonged gamma-irradiation].
AB - It is shown on isolated aorta preparations that prolonged gamma-irradiation of
rats results in depression of endothelium-dependent and endothelium-independent
vasodilatation responses to beta-adrenoceptors stimulation by isoprenaline and M
cholinoceptors by carbachol.
PMID- 9765669
TI - [Analysis of temperature and radiation-induced effects in model and natural
biomembranes using UV-spectroscopy method].
AB - Effects of low-dose gamma-irradiation (up to 1 R) upon UV absorption spectra of
water dispersions of egg yolk lecithin (1:1) and samples of rat liver homogenate
were studied. Clearly detectable changes could be observed in the 200-220 nm
range already under dose loads of several mGy. Radiation sensitivity was shown to
be essentially temperature dependent, being the highest at physiological
temperatures.
PMID- 9765670
TI - [Quantitative characteristics of radiation sickness clinical manifestations in
large-sized laboratory animals exposed to extra-lethal radiation doses. The
endocrine system reactions in dogs and monkeys].
AB - The dynamics of cortisol, insulin and triiodothyronine content of the blood has
been studied in dogs and two monkey species exposed to electron and gamma-neutron
radiations in a wide supralethal--dose range. A calculated value--index of the
endocrine status--has been used for integral estimation the function of the
endocrine system. A considerable disintegration of the functions of separate
endocrine glands has been observed, which correlates with degree of clinical
manifestations in animals and radiation dose.
PMID- 9765671
TI - [Comparative characteristics of lipids, lipoproteins and free radical processes
in blood of rabbits after ionizing irradiation and dietary cholesterol
administration].
AB - Comparative study of spectrum of lypoids and lipoproteins has been conducted and
also of parameters of free radical processes in blood after exposure of organisms
of experimental animals to ionizing irradiation in dose of 5 Gy and inclusion of
cholesterol into diet. Intake of cholesterol to experimental animals irradiated
caused specific impact on indices studied testifying about deep changes in
metabolism. It is important during analysis of complex set of postradiation
metabolic symptoms observed in clinics.
PMID- 9765672
TI - [Fatty acids metabolism of rat liver after extra-lethal gamma-irradiation].
AB - The effect of acute gamma-irradiation of rats at super lethal doses from 25 to
270 Gy on the synthesis and amount of fatty acids, neutral lipids and
phospholipids of liver was studied 48 h after gamma-irradiation. It was shown,
that the synthesis of fatty acids, cholesterol, cholesterol ethers and
phospholipids was activated 48 h after irradiation at 25-100 Gy, but the
irradiation in the doses above 100 Gy inhibited the activation of lipid
synthesis. The amount of fatty acids and neutral lipids of the rat liver
decreased at 15-100 Gy. After irradiation at 200, 270 Gy the fatty acid content
increased significantly, while the decrease of concentration of cholesterol
ethers remained under the control level. This is assumed to be a result of the
radioresistance to a some degree in the system of fatty acid synthesis of the rat
liver to the gamma-irradiation in the super lethal doses.
PMID- 9765673
TI - [Elevation of serum glucose concentration after administration of 5'-AMP to rats
and modulation of this process dynamics following single gamma-irradiation at 1
Gy dose].
AB - Injection of exogenic 5'-AMP to rats was accompanied by pronounced and transient
adenosinemediated elevation of serum glucose concentration. Both efficiency and
duration of the observed hyperglycemic effect were increased within the first
week after single whole-body gamma-irradiation (137Cs) of the animals at 1 Gy
dose. These data suggest modification of purinergic regulation of some processes
of carbohydrate metabolism and disturbance of the organism tolerance towards the
glucose following 1 Gy gamma-irradiation.
PMID- 9765674
TI - [Fluorescent spectral study of synthetic activity of animal blood lymphocytes
under continuous gamma-irradiation].
AB - The effect of continuous gamma-irradiation with dose rate 14.4 cGy/day on the
synthetic activity of rat and rabbit blood lymphocytes stained with acridine
orange was studied by fluorescent microspectrometry. The changes of the synthetic
activity of blood lymphocytes, described by the parameter alpha, occurred in four
main stages. The essential differences in changes of synthetic activity between
rat and rabbit were observed at the first stage. In the rats, parameter alpha
sharply increased, as a result of the stimulatory effect of low dose irradiation.
In the rabbits, being more radiosensitive, at the first stage, parameter alpha
was about control values, as a result of two opposite directed processes,
stimulatory and damaging. At the fourth stage, decrease of the synthetic activity
was both in the rats and in the rabbits owing to damaging effect of continuous
gamma-irradiation during long time.
PMID- 9765675
TI - [Natural antihistone antibodies: their possible role in genesis of radiation
injuries].
AB - The substantial decrease of free natural antibodies reacting with histones under
effect of 4 Gy total dose radiation in sera of healthy animals was established.
It is supposed that the binding of natural antihistone antibodies with histones
reduces the cytotoxic reactivity of histones released from cells under effect of
ionizing radiation. It was determined that complexes of antihistone antibodies
and histones get the ability to react with DNA. The possible biological role of
these complexes is discussed.
PMID- 9765676
TI - [The study of influence of acoustic oscillations on the immunogenesis].
AB - It was found out, that immunomodulative action of low frequency acoustic
oscillations (LFAO) is mediated in mice by enhancement or decreasing of distinct
stages of immunogenesis. Exposure to this factor at intensity of 80 dB varied
number of cells in lymphoid organs, enhanced cell proliferation, improved
cooperative interaction of thymocytes and bone marrow cells in immune response,
caused increase of allogenic stem cells inactivation. On the contrary, exposure
to LFAO at the acoustic pressure of 130 dB caused alternative effects, as
inhibition of immunocompetent cells in interaction.
PMID- 9765677
TI - [Long-term effects of chronic radiation exposure on the level of somatic
mutations in peripheral blood cells].
AB - The level of comatic mutations was studied at GPA locus and in the TCR system at
late times since the onset of radiation exposure in persons exposed to chronic
radiation accidents at the Mayak Production Association in the period 1949-1952.
Individuals with predominantly external gamma-exposure and those with
predominantly internal (mainly due to 90Sr) exposures have been identified among
the exposed population. The average dose to red bone marrow made up 121.5 cSv
with individual values ranging from 11.0 to 462.7 cSv. An increased frequency of
TCR-mutant lymphocytes was noted for exposed subjects. The level of GPA-variant
erythrocytes of different types in the study group did not differ from the
respective value registered in control. The analysis of TCR status showed no
dependence of mutant cell frequency on exposure dose. The assumption is made that
the rate of exposure dose and the nature of its formation (chronic exposure)
exert a decisive influence on the level of somatic mutations in peripheral blood
cells in humans.
PMID- 9765678
TI - [Delayed cytogenetics effects of chronic irradiation of South Ural population].
AB - The evaluation of remote cytogenetic consequences was studied in population,
irradiated at low level during 40 years and more preferentially internally. Mean
level of exposure was in 1950 year at maximum--0.2 Sv/year. In 1993 year it was
equal 1.95 mSv/year. It was revealed statistically significant increasing of
chromosome type of aberrations in lymphocytes of irradiated people in comparison
with control ones. The incidence of chromosome type exchanges in irradiated
individuals comprised 0.43 per 100 cells, and 0.17 per 100 cells in the control.
PMID- 9765679
TI - [Antitoxic features of magnesium oxide under combined radiation and thermal
injury].
AB - Male Wistar rats were exposed to 7.5 Gy total body gamma radiation followed to
the additional full-thickness thermal bum. It was shown, that single
administration of magnesium oxide in 1 hour after combined injury significantly
corrected the early signs of endogenous intoxication. The level of bacterial
endotoxemia decreased as well as serum concentration of toxic oligopeptides;
general blood serum toxicity has been reduced too. Four-fold magnesium oxide's
using as an enterosorbent in combination with antibiotics (doxycyclini,
gentamicini or ciprofloxacin) has ensured 73-100% rats survival. All untreated
animals dead within 30 days after combined injury.
PMID- 9765680
TI - [Effect of substances, absorbing ultraviolet irradiation on Bacillus subtilis
resistance to inactivation and mutagenic action of natural sunlight].
AB - Substances, absorbing UV-irradiation from sunlight (triptophan, cistein,
catalase) decrease Bacillus subtilis resistance to sunlight-induced lethal and
mutagenic damages. Possible, they act as exogenous photosensitizers. Tryptophan
was found to be the most active photosensitizer. Cistein and catalase are not so
active. Casaminoacids being present in the bacterial suspensions during
illumination protect bacteria from mutagenic action sunlight. In this studies we
can demonstrate, that sunlight damage B. subtilis membranes and allows substances
to penetration into cells. Following, that polishing of the environmental by
chemical agents can strength genetic risk for organisms permanently exposure to
sunlight.
PMID- 9765681
TI - [The effect of ionizing radiation and radiosensitizing agent AK-2123 on luminol
dependent chemiluminescence of human neutrophils].
AB - The method of luminol-dependent chemiluminescence (CL) was used to study the
influence of gamma- and fast electrons-irradiation on secretion of reactive
oxygen species of neutrophils in enrich suspension and in presence of all blood
components. In vitro gamma-irradiation (from 5 to 25 Gy) of the neutrophil
suspension inhibited spontaneous CL and activated stimulated by phorbol-12
myristate-13-acetate (PMA) (100 nM) in the period 30-60 min after radiation. The
time of maximum PMA-stimulated CL amplitude was decreased with the dose range
from 2(5) to 25(30) Gy for gamma- and fast electrons-irradiation. The addition of
radiosensitizer AK-2123 (0.05% or 2.2 mM) depressed the early PMA-stimulated CL
response on gamma- and fast electrons-irradiation. The obtained results suggest
that this effect is connected with influence of AK-2123 on ion canals of
neutrophils.
PMID- 9765682
TI - [The state of one of the erythropoiesis regulatory mechanisms after ionizing
radiation exposure].
AB - New quantitative criteria of erythrocytes functional state, based on automated
registration of acid erythrogramme parameters, have been proposed. Enwidened
analysis of adaptive processes in rats erythropoietic system after ionizing
radiation exposure (gamma-rays, 60Co, in doses 0.5; 1.0 and 6.0 Gy) has shown,
that existing in norm mechanism of stimulating effects of dieresis products on
genesis of young red cell forms has been maintained only at exposure 0.5 Gy and
stops to function at higher gamma-ray irradiation doses.
PMID- 9765683
TI - [Study of 137Cs transfer across the placenta to the rat fetuses and effect of
ferrocin on these processes].
AB - The 137Cs placental transfer to the fetuses was studied using a daily oral 137Cs
administration to pregnant rats. At day 19 of gestation, the fetuses receive 0.8%
of the amount administered to the female. A daily application of ferrocinum
reduces the 137Cs content of the female body by 82-84% and decreases the fetal
accumulation down to 0.14%.
PMID- 9765684
TI - Historical overview of the project "Sunshine" in Belgium.
AB - The project "Sunshine" was originally focused on the study of strontium 90 from
the world-wide radioactive fallout and its effects on man. It was one of the most
important projects the USAEC had ever had. It was being conducted as a scientific
study, the primary purpose of which was to discuss the scientific truth and
present the facts publicly. The implementation of the Project in Belgium started
in 1958 and developed into two main directions: a) Environmental survey and b)
Experimental research in both natural and controlled conditions. The paper
described the characteristics of the seven stations "Sunshine" distributed in the
typical agricultural regions of the country, their sampling, the analytical
procedures used and the results obtained (relationship rain/grass; milk/grass;
the observed ratio etc.). Experimental researches performed in natural conditions
aimed to investigate the influence of the yield of the grass/crops on the direct
retention of the deposited fission products; other experiments watched the
transfer of radiostrontium and radiocesium from soils to plants; several
experiments on artificially contaminated pastures grazed by cows allowed to
clarify the importance of such factors as the methods of feeding and types of
pastures for the transfer of major radionuclides to milk. Experimental researches
conducted in controlled conditions dealt with such topics as study on the
retention of strontium 90 in soil, studies on foliar contamination by
radiostrontium and radiocesium, absorption and distribution in plants of Sr and
Ca, discrimination between Sr and Ca during the transfer from feed to cow milk,
study on the contamination by the major fission products of the milk products.
Finally tentative countermeasures were tested: application of significant amounts
of stable strontium in contaminated soils and influence of alginate on
radiostrontium absorption from contaminated milk to piglets.
PMID- 9765686
TI - Induction chemotherapy followed by simultaneous hyperfractionated
radiochemotherapy in advanced head and neck cancer. A pilot study.
AB - PURPOSE: To evaluate the feasibility of induction chemotherapy followed by
concomitant chemotherapy and hyperfractionated irradiation in locally advanced,
inoperable head and neck cancer. METHODS: A pilot study was undertaken comprising
3 cycles of cisplatinum (100 mg/m2, day 1) and 5-fluorouracil (1000 mg/m2 in
continuous intravenous infusion over the first 120 h) followed by bifractionated
radiotherapy applied to tumor/involved lymph nodes up to the dose of 74.4 Gy
given in 2 fractions of 1.2 Gy daily for 5 days a week combined with concomitant
weekly cisplatinum infusion (50 mg/m2). RESULTS: Six patients were enrolled in
the study. All of them completed the protocol therapy. Severe mucositis and
myelotoxicity were the most common acute side effects observed in all and in 5 of
the patients, respectively. Acute toxicity required interruption of concomitant
chemotherapy in 5 cases and in 2 interruption of radiotherapy was necessary.
Opioid analgesic parenteral therapy was administered in 4 patients. Three of them
had to be hospitalized. One patient experienced cerebral stroke 1 day after the
completion of therapy and died 7 days later. Due to high acute toxicity, patient
accrual was terminated after 6 patients. At the mean follow-up of 17 months, 4
patients are alive, 3 of them are free of disease and in 1 local progression has
been diagnosed. CONCLUSIONS: High acute toxicity of induction cisplatinum and 5
fluorouracil followed by concomitant cisplatinum and hyperfractionated
irradiation calls for less toxic treatment schedules in locally advanced
inoperable head and neck cancer.
PMID- 9765685
TI - [Endocrine orbitopathy: comparison of the long-term result and classification
after radiotherapy].
AB - BACKGROUND: This study compares 4 classifications in patients with progressive
refractory Graves orbitopathy (GO) and examines their prognostic value in long
term follow-up. PATIENTS AND METHODS: From 1984 to 1994, 60 consecutive patients
(49 female, 11 male) received 20 Gy (10 x 2 Gy) radiotherapy with 6 MV Linac
photons. Ocular symptoms and functional impairment was evaluated according to 4
GO-classification systems: Werner-, modified ATA- and Stanford-Score and
Ophthalmopathy-Index (OI) according to Grussendorf. In addition, all patients
noted their subjective response on a linear scale (0 to 100%). RESULTS:
Improvement was achieved within 1 year after radiotherapy according to the Werner
Score in 28 (47%) patients in > or = 1 symptom category, according to the
modified ATA-score in 48 (80%), the Stanford-score in 47 (78%) and the OI-Score
in 55 (92%) patients (reduction of > 2 points). The Werner-Score correlated less
to the other scores (coefficient r < 0.5) than the other scores among themselves
(r approximately 0.9). The ATA-Score improved in the different symptom categories
between 47% (stage VI) and 87% (stage V). The OI-Score was reduced by a mean of 6
points. The patients reached a mean subjective improvement of +70 +/- 25%. Acute
or chronic side effects were not observed. In multivariate analysis the "male
gender" (p = 0.08), a "symptom duration prior to radiotherapy > 1 year" (p =
0.14) and a "high symptom category" (p = 0.11) indicated a negative prognostic
trend. CONCLUSIONS: External radiotherapy is effective for severe, progressive GO
after pretreatment. A minimum follow-up of at least 12 months and standardized
classification and success criteria are required.
PMID- 9765688
TI - [Remarks on the dosage problem in HDR brachytherapy].
AB - BACKGROUND: In HDR brachytherapy activity distributions can be achieved which
were unknown in LDR brachytherapy. For this reason the classical dosage systems
can only be used with caution in HDR brachytherapy. METHODS: Different simple
applications are used to investigate the effect of various activity distributions
on dose and integrated reference air kerma. RESULTS: Within the classical LDR
dosage systems dose and integrated reference air kerma were equivalent. Due to
the possibility to "optimize" the activity distribution in HDR brachytherapy this
is not longer the case. Different optimization algorithms and different
optimization goals may lead to quite different activity distributions and
different integrated reference air kerma values even if the source positions are
the same. For target volume oriented optimization schemes a dosage system is
described which is based on dose-volume-histograms. CONCLUSIONS: A widely
accepted dosage system in HDR brachytherapy is missing. The dosage system
described in this paper may be useful in solving this problem.
PMID- 9765687
TI - [D-xylose test of resorption as a method to determine radiation side effects in
the small intestine].
AB - BACKGROUND: The D-xylose test is the most important method to determine a
disorder of carbohydrates resorption in proximal small intestine. The application
is based on an impaired resorption due to pathological change of small intestine
surface, leading to a decreased blood level or decreased excretion in urine.
PATIENTS AND METHOD: D-xylose test was applied in 91 patients before, shortly
after, 1/2 and 1 year after radiotherapy. All patients received an abdominal
radiotherapy. We determined the blood level of D-xylose by a capillary blood
sample 1 hour after oral D-xylose administration. RESULTS: A significant decrease
of the mean blood level of D-xylose to 1.88 mmol/l was determined after
radiotherapy in comparison with 2.17 mmol/l before radiotherapy. Half a year
after radiotherapy the mean blood level of D-xylose returned to normal. Regarding
a threshold value of D-xylose blood level of 1.70 mmol/l 29 patients (32%) showed
a pathologically decreased D-xylose resorption after radiotherapy. Twenty out of
the 29 patients already showed a normal resorption half a year after the
determination of the resorption disorder, 5 patients after 1 year and 4 patients
after 1 1/2 years. There was no correlation between the detection of a disorder
of D-xylose resorption and of a loss of body weight. The acute clinical side
effects seemed to be more marked in connection with a disorder of D-xylose
resorption, but this correlation is not significant. Eleven or 14 of the 29
patients, respectively, with pathologically decreased D-xylose resorption only
had complaints of lower or upper gastrointestinal tract, respectively, and 10
patients did not have abdominal complaints at all. CONCLUSIONS: The D-xylose test
is an important and simple method for determination of radiogen induced
carbohydrate malabsorption in proximal small intestine. By means of it radiation
side effects on small intestine can also be determined in patients who are
otherwise free of complaints.
PMID- 9765689
TI - [First experiences with computer-assisted frameless stereotactic interstitial
brachytherapy (CASIB)].
AB - PURPOSE: To reach an optimal treatment result and to avoid damage to critical
structures a homogeneous dose distribution in the tumor volume with a rapid
decreasing dose to the surrounding structures is necessary. Fractionated
interstitial brachytherapy of tumors in the ENT region employing needles depends
on exact localization of the target volume during all fractions. Therefore
reproducibility of positioning of the needle(s) plays an important role. MATERIAL
AND METHODS: We used the ISG Viewing Wand system in combination with the Vogele
Bale-Hohner (VBH) head holder and a new targeting device. Point of entrance,
pathway, and target point of the needle were planned and insertion of the needle
simulated in advance. To date we have treated 7 patients with inoperable tumors
in the ENT region. The actual position of the needle in the control CT was
compared to the planned position. RESULTS: The accuracy of positioning of the
needle depended on the location of the tumor. In a patient with a recurrent
retroorbital adenocarcinoma the mean accuracy was 1 mm. Due to soft tissue
displacement in the neck region and the resulting necessity to readjust the
targeting device the needle was placed with a mean deviation of 15 mm between the
planned and the actual position. CONCLUSIONS: Computer-assisted frameless
stereotactic interstitial brachytherapy allows for precise, reproducible and
preplanned insertion of hollow needles into target structures closely adherent to
the surrounding tissue, thus avoiding damage of neighbouring structures. This
technique is of great advantage in treating deeply seated tumors which are fixed
to bony structures, especially at the skull base. Inaccuracy in the neck region
caused by soft tissue shift requires improvement of the immobilization in this
region.
PMID- 9765690
TI - [Spinal metastases of malignant gliomas].
AB - PURPOSE: Extracranial metastases of malignant gliomas are rare. We report 2 cases
with spinal metastases in patients suffering from glioma. PATIENTS AND METHOD:
Two patients (33 and 57 years old) developed spinal canal metastases of a
glioblastoma multiforme and anaplastic astrocytoma Grade III respectively 25 and
9 months after surgical resection and radiotherapy. Both metastases were
confirmed pathohistologically. RESULTS: Intraspinal metastases were irradiated
with a total dose of 12.6 Gy and 50 Gy. Treatment withdrawal was necessary in one
patient due to reduced clinical condition. Regression of neurological symptoms
was observed in the second patient. CONCLUSIONS: Spinal spread of malignant
glioma should be considered during care and follow-up in glioma patients with
spinal symptoms.
PMID- 9765691
TI - Treatment of radiation proctitis with hyperbaric oxygen: what is the optimal
number of HBO treatments?
AB - AIM: Our objective was to investigate the effectiveness of hyperbaric oxygenation
(HBO) in the treatment of radiation proctitis. The current literature was
reviewed with regard to the necessary number of HBO treatments. PATIENTS AND
METHODS: Two patients with proctitis after pelvic irradiation were treated with
40 and 38 HBO treatments, respectively. Hyperbaric oxygenation was delivered at
240 kPa over 90 min. RESULTS: In one patient, proctosigmoidoscopy showed a
significant improvement after 40 HBO sessions. The other patient interrupted
therapy after 38 HBO treatments without subjective change. The reported number of
HBO sessions for a successful treatment of radiation proctitis ranges from 12 to
90. CONCLUSION: HBO should be considered before more invasive treatment
modalities are performed for radiation proctitis.
PMID- 9765692
TI - [Oxygenation status of squamous cell carcinoma of the head and neck: comparison
of primary tumors, their neck node metastases and normal tissue].
AB - AIM: Investigation of the relationship between the pO2-status of primary tumors,
their cervical neck node metastases and normal tissues in squamous cell
carcinomas of the head and neck. PATIENTS AND METHODS: Pretreatment oxygenation
of primary tumors, their neck node metastases and of the contralateral
sternocleidomastoid muscle was assessed in 16 patients with histologically proven
advanced squamous cell carcinomas of head and neck. Oxygenation was measured with
a polarographic microelectrode system (Eppendorf-pO-Histograph). Using CT/MRT
additionally the volume of the tumors was estimated. RESULTS: A highly
significant correlation existed between the median pO2 of primary tumors and
their neck node metastases and between the relative proportion of hypoxic values
(< 5 mm Hg) of both anatomic sites (both p = 0.0001) (Figure 1). Primary tumors
were not different from their neck node metastases, neither regarding the pO2
median values nor in view of the relative frequency of hypoxic values (Table 1).
No correlation was found between the volume of primary tumors and the one of
their neck node metastases. For volume of tumors and the oxygenation status no
relationship was found as well. Significantly different was the median pO2 in the
muscles from the one of the malignant tissues (p = 0.0004). CONCLUSION: The
results suggest that for to estimate the oxygenation status of squanious cell
carcinomas of the head and neck pO2 measurements of primary tumors and neck node
metastases are equally sufficient.
PMID- 9765693
TI - [A randomized trial of concurrent chemoradiotherapy versus radiotherapy in
advanced carcinoma of the uterine cervix].
PMID- 9765694
TI - [Isolated vaginal recurrences in endometrial carcinoma: treatment results using
high-dose-rate intracavitary brachytherapy and external beam radiotherapy].
PMID- 9765695
TI - [Continuous intravenous infusional 5-FU compared with bolus administration in
metastatic colorectal carcinoma].
PMID- 9765696
TI - [Adjuvant radio-chemotherapy is effective in the treatment of Dukes B and C
rectal cancer: results of a randomized controlled Norwegian trial].
PMID- 9765697
TI - [Management of the unscheduled interruption or prolongation of a radical course
of radiotherapy].
PMID- 9765698
TI - [Endonasal sequelae after hypophysectomy].
AB - Each year, 15 transvestibular transseptal transsphenoidal hypophysectomies are
performed in Lausanne. The aim of the study was to determine the complications
rate of our procedure and their influence on the life quality of patients.
Questionnaires were sent to 178 patients, operated between 1984 and 1995. 125
questionnaires were returned. Out of those, 73 patients accepted to undergo a
control rhinoscopy. The most frequent complains were nasal obstruction and
crusting (38% each), whistling while breathing through the nose (12%), and
stuffiness of the upper lip or teeth (7%). Endoscopically, we detected an
anterior septal perforation in 10 cases (13.7%), 8 (80%) of which were
symptomatic and a posterior septal perforation in 6 cases, all of them being
asymptomatic. Finally, 36% of the patients had no complains and 19% of them had
an improvement of respiration after the operation. Of the whole series of 178
patients, only 5% had complications requiring an ENT follow-up for longer than 6
months after having been operated.
PMID- 9765699
TI - [KTP laser in the upper airways in children: preliminary study on 27 lesions].
AB - The KTP Laser was recently introduced in otolaryngology, and is increasingly
used. This report describes treatment of 27 upper airway lesions in 24 children
using KTP Laser over a two year and half period at the Children's Hospital of La
Timone in Marseille. Comparison of results with CO2 Laser were made for the three
most frequent pathologies of the series which were choanal atresia (n = 14),
laryngotracheal stenosis (n = 6) and laryngeal paralysis (n = 3). The convenience
of fiber delivery, concomitant telescopic control and low grade oedematous
reaction are the main advantages over the CO2 Laser. As reported in the
literature, we observed that healing was longer for KTP Laser than for CO2 Laser.
Delay to healing may be an advantage in the management of choanal atresias and
laryngeal stenosis.
PMID- 9765700
TI - [Gadolinium and contrast medium MRI of the acoustic nerve in patients with
meningeal neuritis and acoustico-facial syndrome].
AB - Twelve cases of vestibular neuritis were investigated in gradient echo MRI with
gadolinium. Only 3 severe cases associated with an acoustico facial syndrome (2
cases of herpes zoster oticus and one case after influenzae) demonstrated focal
enhancement within the internal auditory canal on post contrast T1 weighted
images. This enhancement involved at least 2 differents nerves. These 3 severe
cases associating sensory neural hearing loss and facial palsy revealed a
meningeal reaction after cerebrospinal fluid examination. The enhancement lasted
a long time (up to 10 months) in one case of RAMSAY HUNT syndrome associated with
a chronic lymphocytic leukemia. The MRI was able to confirm the anatomical
reality of the vestibular neuritis and more precisely of the meningoneuritis and
gave arguments for the theory of the polyneuropathy of Adour. Enhancement at MRI
seems correlated with the severity of the affection (permanent vestibular
areflexia in 3 cases and permanent hearing loss in 1 case).
PMID- 9765701
TI - [Dilator muscles of the pharynx and their implication in the sleep apnea syndrome
of obstructive type. Review of the literature].
AB - Pathophysiology of the obstructive sleep apnea syndrome shows three components:
intra and peripharyngeal obstacles, excessive pharyngeal wall compliance and
upper airway dilator muscle dysfunction. The intent of this paper is to provide
an overview of the anatomy, histology, physiology and pathophysiology of the
upper airway dilator muscles based on previously published articles. The upper
airway dilator muscles can be separated in three different systems, main and
accessory dilators, local and regional. They act in synergy. Their contraction
occurs at the beginning of inspiration, thus maintaining opened the pharyngeal
lumen through inspiration. Their action is modulated by several chemo or physical
stimuli. In some apneic patients, these muscles demonstrate a dysfunction:
hyperactivity during wakefulness, electromyogram wave amplitude reduced, delayed
contraction during sleep and abnormal response to stimuli. This dysfunction might
be due to neuromuscular histological abnormalities, a "fatigue" phenomenon or a
central nervous command abnormality. Current explorations underlining an upper
airway dilator muscle dysfunction will enable practitioners to decide which
treatment is best and understand therapeutical failures; it will also help
develop new therapeutical techniques such as functional electrical stimulation of
the hypoglossal nerve/upper airway dilator muscles.
PMID- 9765702
TI - [Spheno-ethmoidal rhinoscleroma. Report of a case and review of the literature].
AB - We report an unusual case of spheno-ethmoidal rhinoscleroma. This chronic
granulomatous disease occurs sporadically in Western Europe. Culture is necessary
for diagnosis showing the causative organism of rhinoscleroma, Klebsiella
rhinoscleromatis. Immunocytochemistry is used in any suspicious case with a
negative culture. Antibiotics are the mainstay of therapy for several weeks,
using ciprofloxacine or rifampicin, until the nasal biopsies demonstrated no
Klebsiella organism.
PMID- 9765703
TI - [Etiological diagnosis of sensorineural deafness in children: a year-long review
of genetic counseling for deaf people].
AB - From February 1996 to January 1997, 74 patients from 53 sibships underwent
genetic counselling for sensorineural deafness at the Pasteur Hospital, Paris,
France. Genetic counselling was based on the etiological diagnosis of the hearing
impairment, by an audiological and non-audiological examination program. At the
first examination, 31 families presented with a familial deafness and 22 families
with apparently one affected individual. However, familial audiological
examinations revealed familial deafness in 5 of these 22 families. Consequently,
a total of 36 families had hereditary hearing impairment and the etiological
groups showed the following distribution: non-syndromic deafness (14 families),
syndromic deafness (12 families), probable syndromic deafness (5 families), and
incomplete assessment (5 families). Out of the remaining 17 families in which
affected individuals were sporadic cases, the etiological groups were as follows:
acquired deafness (2 families), probable syndromic deafness (5 families), unknown
cause (5 families), and incomplete assessment (5 families). Etiological
assessment is discussed, with reference to the cost-effectiveness of this
examination program. In light of this preliminary report, we present a model of
assessment for the etiological diagnosis of sensorineural deafness in children
and young adults.
PMID- 9765705
TI - [Microcystic sclerosing adnexal carcinoma: 2 case reports. Diagnostic and
therapeutic difficulties].
AB - Microcystic adnexal carcinoma is a recently described malignant neoplasm of
adnexal structure. It remains frequently misdiagnosed. These tumors are
characterized by their slow progression and by local aggressivity with local
recurrences. The best treatment appears to be surgical excision with
microscopically controlled margin. We report two cases of microcystic adnexal
carcinoma recently observed at Institute Gustave Roussy.
PMID- 9765704
TI - [Cochleovestibular disorders associated with hemifacial spasm: an outcome after
microvascular decompression of the facial nerve].
AB - Twelve patients underwent microvascular decompression by retrosigmoid approach to
relieve severe hemifacial spasm. The surgery was done under intraoperative
monitoring of the auditory function. Assessment at Day 2, Day 10, 2 months and 6
months after the operation found that the surgery had resulted in 9 recoveries, 3
improvements and 1 failure. Brain stem auditory evoked potentials monitoring
showed that the interposition of Teflon between the vascular loop and the facial
nerve is a critical stage for the auditory function. Six of the twelve patients
were also complaining of cochleo-vestibular disorders: vertigo and tinnitus, or
hearing loss and tinnitus, or vertigo alone. The surgery improved at least one of
these cochleo-vestibular symptoms in each one of the patients. There was one
hearing improvement, vertigo disappeared in three cases out of four, and tinnitus
disappeared in four cases out of five. The possibility of a concomitant
compression of cochleo-vestibular and facial nerve was investigated using
cochleovestibular tests, radiological data and intra-operative findings.
PMID- 9765706
TI - [Amelanotic melanoma of the frontal sinus: a case report].
AB - We report a case of frontal sinus amelanotic melanoma in a 76-year-old man. The
diagnosis was based mainly on immunohistochemical studies. Despite an aggressive
therapeutic regimen associating surgery and radiotherapy, outcome was fatal 8
months after onset of symptoms.
PMID- 9765707
TI - [Nasopharyngeal perforation: an exceptional accident during digestive endoscopy].
AB - A case of an endoscopic nasopharynx perforation is reported. As we known, this
accident has never been described. During introduction of a duodenal tube
appeared a subcutaneous neck emphysema. Radios revealed pneumomediastinum,
pneumoperitonitis and retropneumoperitonitis. Nasofibroscopy affirmed the
diagnosis. The too fast death of this 92 years old patient didn't allow an
adapted therapeutic.
PMID- 9765708
TI - [A report of two familial cases of Michel syndrome (bilateral agenesis of the
inner ear)].
AB - In two siblings, wearing conventional hearing aid, presenting profound but not
total congenital deafness, with no particular antecedents, the imaging destined
to confirm the indication of a cochlear implant revealed a total bilateral
agenesis of the inner ear. In one of the children, this imaging was confirmed by
an exploration of the middle ear performed during a tonsillectomy that was
otherwise necessary. We will summarize the literature concerning Michel's
Disease, exceptional in its princeps form, and we will discuss the manner of
action of conventional devices in these cases which are a priori without any
sensorial element.
PMID- 9765709
TI - [Intra-labyrinthine schwannomas: a report of two cases].
AB - Intralabyrinthine schwannomas are rare tumors of vestibule, cochlea, semicircular
canals, or some combination of these three. In the past, they have been found at
autopsy or as incidental finding at surgery. Since the advent of magnetic
resonance imaging (MRI) with intravenous gadolinium contrast, the preoperative
diagnosis is possible. We report two cases of intralabyrinthine schwannoma: one
case of intralabyrinthine schwannoma extended into the internal auditory canal
(IAC), a second case of tumor restricted to the vestibule. No characteristic
clinical presentation of this tumor is reported in the literature. In patients
with vestibular weakness (vertigo and no response of caloric testing), MRI with
gadolinium contrast can make the diagnosis of intravestibular tumor. In patients
with the more common IAC acoustic neuromas, MRI can demonstrate extension of
tumor into the labyrinth; diagnosing this extension preoperatively is important
to plan surgical treatment.
PMID- 9765710
TI - ["Aquatic" dissection of the facial nerve for the surgery of acoustic neurinoma].
AB - We describe a procedure facilitating dissection of the facial nerve from acoustic
neuromas, consisting of a pulsed irrigation of serum. This seems to minimize
nerve manipulation and thus surgical trauma.
PMID- 9765711
TI - [A sinus neglected for so long...].
PMID- 9765712
TI - [Acute and chronic sphenoid sinusitis. Review of the literature].
AB - Isolated involvement of the sphenoid sinus is a relatively uncommon entity. We
present a review of the most important series. Acute and chronic diseases are
separated. Acute sphenoid sinusitis is a potentially catastrophic infectious
disease. It is frequently initially misdiagnosed, and, due to the severe
intracranial complications, a genuine medical and surgical treatment is
recommended. Chronic sphenoid lesions may pose a problem of etiologic diagnosis.
It may be difficult to differentiate between benign and malignant lesions. The
most common presenting symptom is headache, followed by visual symptoms and
cranial nerves palsies. Radiographically, computed tomography is the gold
standard. Treatment includes antibiotic therapy and surgical drainage. This
drainage is now done through an endoscopic approach.
PMID- 9765713
TI - [Digital multi-filter auditory prosthesis: study of its efficiency in function of
number of filters and their programming].
AB - We designed a prototype of a 7-filter digital auditory prosthesis table
prototype. For each of these filters frequency band width, amplification and
compression were programmable in order to adapt these parameters to the deaf
patient's audiometric particularities. We compared the hearing improvement it was
possible to obtain either with the 3-analogue-filter auditory prosthesis Triton
3004 from Siemens, or with our prototype as a function of the number of filters
(3, 4 or 7) and their frequency band width programmability. We tested 21 patients
suffering from middle or severe neurosensory hearing loss. This study allows to
demonstrate that to overpass the present analogue T004 device a 7 programmable
width-filter strategy seems to be the most appropriate. Further studies
benefiting with material improvement of our prototype and finer audiometric
adjustment of filter strategies as well as long term clinical studies have to be
carried out.
PMID- 9765714
TI - [Cochlear implant and cerebral dominance].
AB - On right handed people the right ear is considered to transmit speech
information, and the left ear musical and cognitive information. These dominating
ear properties are not exactly symmetrical in the left handed population, and are
more consistent in females than in males. CI efficacy assessment is strongly
based on speech intelligibility performances, because these criteria allow to
measure the social reinsertion and communication possibilities. Consequently, one
may ask if the relationship of the implanted side and the patient's handness
could not be an important factor of this CI efficacy. We studied this
relationship on 71 post-lingually deaf adult implantees. We measured patients
handness using the Schachter's version of the so called Edimburg questionnaire
described by Geschwind; this measurement has been moderated to take count of
ambidextrous and mixed-handed population. Post operative performances has been
assessed using the Francophone Protocol devoted to adults. We found that there is
no significant correlation between these post-operative performances and the
studied relationship. We estimate: 1) This absence of correlation is probably due
to the high number of data which lead to determine the ear for implanting. 2) As
far as this choice is feasible, dominating ear must nevertheless be elected, not
only for theoretical reasons, but because the dominating hand may be easily
employed for antenna adjustment. 3) As handness is strongly evident only after 4
y.o., and as left-handness seems to be more frequent on a congenitally deaf
population, this choice is more problematic on less than 2 y.o. deaf children.
PMID- 9765715
TI - [Cochlear implant in the aged patient].
AB - Despite the fact that elderly people live frequently alone and frequently have
difficulties of vision, is it reasonable to refuse to supply a patient with a
cochlear implant only because he is too old? We compare the results of 87 post
lingually implantees as a function of age, less than 60 years (young) and 60
years or more (old). We assessed the implant efficacy using the Protocole
Francophone d'Evaluation (PFE), appreciated the speech-therapist's opinion and
the patient's satisfaction, and counted the number of hours per day the implant
was used (H/D). The PFE score was significantly higher in young than old. However
the speech-therapist's opinion and the patient's satisfaction as well as H/D did
not differ significantly in the 2 series. Elderly people are supplied with a
great benefit from cochlear implants. Therefore age is not a contraindication for
implantation.
PMID- 9765716
TI - [Indications for the cochlear implant in partial deafness of the adult].
AB - The last (may 1995) NHI Consensus Development Conference on cochlear implant
recommends to extend the use of cochlear implant for adult patient suffering from
bilateral acquired severe hearing impairment. Its indications are a severe-to
profound sensorineural hearing loss bilaterally presenting an open-set sentence
recognition scores less than or equal to 30 percent under best aided conditions.
We report the results of our 4 first implantees responding to these criteria, and
discuss the mechanisms of the speech intelligibility improvement which has been
obtained.
PMID- 9765717
TI - [Necessity of auditory and academic supervision in patients with unilateral
hearing disorder. Retrospective study of 175 children].
AB - This report reviews a consecutive series of 175 children suffering from
unilateral hearing loss of 20 dB or more evaluated at the Clocheville Hospital
between 1980-1991. We found no numerical preponderance of gender nor of side
impairment. The mean age of diagnosis was 6.9 years. Based on speech frequency
threshold averages, the loss was profound in 49.7%. 32.8% of the children
experienced a deterioration of hearing of 10 dB or more. 40.4% of the children
had repeated a grade during primary school (versus 16.3% in normal hearing
population, p < 0.001). Monaural deafness especially when more than 40 dB, or
delayed identification is significantly associated with a grade failure. A
concerted effort aimed at early identification and management strategies in cases
of unilateral hearing loss in children is warranted.
PMID- 9765718
TI - [Peripheral auditory lateralization].
AB - Neuropsychological studies have demonstrated that language perception is
lateralized at the hemispheric level. There is also much evidence for a
peripheral lateralization of the auditory system in humans. Spontaneous
otoacoustic emissions are more frequent in the right than in the left ear. The
medial olivo-cochlear system is also more functional in the right than in the
left ear in normal subjects. The study of specific samples shows that this
asymmetry is found in professional musicians which have more functional efferent
system in both ears. A link is hypothesized between peripheral and central
laterality because of a dysfunctional peripheral asymmetry in pathological cases
which show hemispheric lateralization disorders. Consequences of those
pathological data will be discussed.
PMID- 9765719
TI - [Static balance is controlled by a non-linear dynamic system].
AB - Different techniques of stabilometric signal analysis have been used in order to
study the adaptation of the fine postural control system to the wearing of
corrective glasses with or without prisms. The comparison between the results
obtained with conventional techniques and those obtained with non-linear dynamic
methods demonstrates the better efficiency of the latter. These results confirm
that the postural system behaves as a non-linear dynamical system and may explain
the outstanding sensitivity of the fine postural system to small perturbations.
PMID- 9765720
TI - [Bilateral closure of the nasal cavity. An original surgical technique of
treatment of severe recurrent epistaxis in Rendu-Osler disease].
AB - In the Rendu Osler disease, epistaxis are seen in 80 to 90% of patients, and the
multiple treatments that have been proposed have each shown their failure to
achieve satisfactory results. We propose, in the case of abundant epistaxis, a
bilateral closure of the nasal cavity. This technique has been initially
described by Young in 1967 in the treatment of chronic atrophic rhinitis. This
operation was carried out in two patients who presented with serious daily
epistaxis, poorly tolerated, and refractory to several treatments. Neither of
these patients has presented a post-operative bleeding episode with a one year
and six months follow-up respectively. Anatomically, the results are satisfactory
in both patients, with total closure of the nasal cavity. Functionally, both
patients are satisfied, with an appreciable improvement in the quality of life
despite total nasal obstruction.
PMID- 9765721
TI - The clinical practice guideline: an evolving health care technology.
PMID- 9765722
TI - Surgical management of early stage invasive breast cancer (stage I and II).
Provincial Breast Disease Site Group.
AB - GUIDELINE QUESTION: What is the optimal surgical management of early stage
invasive breast cancer (stage I and II)? More specifically, what is the relative
efficacy (and safety) of breast conservation therapy (lumpectomy with axillary
dissection) compared with modified radical mastectomy? OBJECTIVE: To make
recommendations about surgical management and techniques in the treatment of
early stage invasive breast disease (stage I and II). OUTCOMES: Survival, local
recurrence (for lumpectomy patients) and quality of life are the primary outcomes
of interest. PERSPECTIVE (VALUES): Evidence was selected and reviewed by 6
members of the Ontario Cancer Treatment Practice Guidelines Initiative, Disease
Site Group for Breast Cancer (Breast DSG). Earlier drafts of this evidence-based
recommendation have been reviewed, discussed and approved by the Breast DSG,
which comprises surgeons, medical oncologists, radiation oncologists,
epidemiologists, a pathologist and a medical sociologist. There was no consumer
participation in the development of this guideline. QUALITY OF EVIDENCE: There
are 7 randomized controlled trials (RCTs) comparing breast conservation therapy
with mastectomy in women with early stage breast cancer. BENEFITS: In 6 RCTs, no
statistically significant differences were detected in survival rate between the
mastectomy and conservative therapy (lumpectomy) groups. In 1 RCT, a
statistically significant differences was detected in favour of the mastectomy
arm; however, this was an early trial with substantial methodologic weaknesses.
HARMS: None. PRACTICE GUIDELINE: Women with early stage invasive breast cancer
(stage I and II) who are candidates for breast conservation therapy (see
discussion of technical factors) should be offered the choice of either breast
conservation therapy (excision of tumour with clear margins and axillary
dissection) or modified radical mastectomy. The choice is an individual one for
the patient, and thus she should be fully informed of the options, including the
risks and benefits of each procedure. She should be informed that breast
irradiation is part of the procedure for breast conservation therapy. In
addition, she should be aware of the potential need for further surgery if the
margins are positive. For further information about the use of radiotherapy in
the management of early stage breast cancer, please refer to the Ontario Cancer
Treatment Practice Guidelines Initiative's practice guideline Breast Irradiation
in Women with Early Stage Invasive Breast Cancer Following Breast Conserving
Surgery.
PMID- 9765723
TI - Chemotherapy in stage IV (metastatic) non-small-cell lung cancer. Provincial Lung
Disease Site Group.
AB - GUIDELINE QUESTION: In patients with metastatic, stage IV non-small-cell lung
cancer (NSCLC) does chemotherapy improve survival and quality of life? OBJECTIVE:
To make recommendations about the role of chemotherapy in the treatment of
metastatic (stage IV) NSCLC. OUTCOMES: Survival and quality of life are the
primary endpoints of interest. Specifically, 1-year survival will be considered.
PERSPECTIVE: Evidence was selected and reviewed by 3 medical oncologists and the
project coordinator of the Ontario Cancer Treatment Practice Guidelines
Initiative. Drafts of this document have been circulated and reviewed by the
Provincial Lung Disease Site Group (Lung DSG). The Lung DSG comprises medical and
radiation oncologists, pathologists, surgeons, epidemiologists, a psychologists
and a medical sociologist. There was no consumer participation in the development
of this guideline. QUALITY OF EVIDENCE: There were 3 meta-analyses available for
review, but only 1 is discussed in detail. The largest and most comprehensive
meta-analysis is based on 11 randomized controlled trials involving 1190
patients. The main comparisons were chemotherapy plus supportive care versus
supportive care alone. The largest trial included in the meta-analysis involved
randomization of 188 patients, and the smallest trial involved randomization of
32 patients. Only trials that had accrued patients between Jan. 1, 1965, and Dec.
31, 1991, were included in the analysis. BENEFITS: A survival benefit at 1 year
was seen for the group of patients treated with chemotherapy (pooled hazard ratio
0.84; 95% confidence interval [CI], 0.74 to 0.95). Subgroup analyses suggested a
benefit for patients receiving chemotherapy regimens containing cisplatin (pooled
hazard ratio, 0.73; 95% CI, 0.63 to 0.85; relative risk reduction for death, 27%;
absolute improvement in 1 year survival, 10%; 95% CI, 5% to 18%; gain in median
survival 1.5 months; 95% CI, 1 to 2.5 months). No benefit for patients treated
with chemotherapy was found beyond 1 year. None of the randomized trials
successfully measured quality of life using QOL assessment instruments. No firm
conclusions can be made about the potential benefits (as measured by quality of
life) that chemotherapy has for patients with metastatic NSCLC, as there are no
available data from randomized controlled trials. However, several trials have
documented relief of cancer-related symptoms, such as pain, cough, hemoptysis or
dyspnea in the majority (approximately 70%) of patients. HARMS: In a subgroup
analysis of trials that used long-term alkylating agents other than cisplatin (an
approach no longer used as therapy in NSCLC) as part of the chemotherapy regimen,
the meta-analysis demonstrated a detrimental effect of chemotherapy on survival
(pooled hazard ratio, 1.26; 95% CI, 0.96 to 1.66, p = 0.09). In general,
myelosuppression, sepsis resulting in hospitalization, drug-specific toxicities
and death are potential complications of chemotherapy.
PMID- 9765724
TI - Use of vinorelbine in non-small-cell lung cancer. Provincial Lung Disease Site
Group.
AB - GUIDELINE QUESTION: Is there a role for the use of vinorelbine in the treatment
of patients with non-small-cell lung cancer (NSCLC)? OBJECTIVE: To make
recommendations about the use of vinorelbine in the management of patients with
NSCLC. OUTCOMES: Survival is the primary endpoint of interest. Response and
toxicity are secondary endpoints. PERSPECTIVES: Evidence was selected and
reviewed by the 4 members of the Lung Disease Site Group (Lung DSG). Early drafts
of this practice guideline were reviewed by the Lung DSG and by the Systemic
Treatment Program Committee (STPC). These committees comprise medical and
radiation oncologists, pathologists, surgeons, epidemiologists, pharmacists,
nurses, a psychologist, a medical sociologist and administrators. No consumers
participated in the development of this guideline. QUALITY OF EVIDENCE: Only
evidence from randomized controlled trials (RCTs) and phase II studies was
evaluated. Six RCTs and 5 phase II studies were reviewed and are discussed in
this report. Of the 6 RCTs, 3 have been fully published. BENEFITS: Vinorelbine,
either as a single agent or in combination with cisplatin, produces higher
response rates (12%-37%) than other single agent vinca alkaloids (10%-20%) in
patients with previously untreated NSCLC. Two of 3 RCTs that reported survival
differences demonstrated a survival benefit for previously untreated patients
with NSCLC when treated with vinorelbine in combination with cisplatin as
compared with patients treated with either vindesine plus cisplatin (p = 0.04) or
leucovorin plus 5-fluorouracil (p = 0.03). The third study reported no
statistically significant difference between patients treated with vinorelbine
alone and those receiving vinorelbine plus cisplatin. HARMS: The major toxic
effects are hematologic. Neutropenia is the dose-limiting toxic effect. However,
there is less neurotoxicity than with other vinca alkaloids (e.g., vindesine) and
less nausea and vomiting than with other active agents used in the treatment of
NSCLC. PRACTICE GUIDELINE: Evidence from randomized controlled trials supports
the use of vinorelbine as an option for the first-line treatment of patients with
locally advanced or metastatic NSCLC. Whether vinorelbine is used as a single
agent or in combination with cisplatin depends on the anticipated trade-offs
between the expected symptomatic benefits of a higher response rate with the
combination (as seen in randomized controlled trials) and the increased toxicity.
Evidence for a possible survival advantage for the combination of vinorelbine and
cisplatin over vinorelbine alone is conflicting. There is insufficient evidence
at the present time to advocate the use of vinorelbine in previously treated
patients who have recurrent or progressive disease. Similarly, there is
insufficient evidence at the present time to advocate the use of vinorelbine as
adjuvant or induction therapy for patients with stage I, II or early stage III
disease. The enrolment of patients with NSCLC in clinical trials is encouraged.
PMID- 9765725
TI - Canadian perspectives on breast cancer: the challenges for the future.
PMID- 9765726
TI - Personal experience. Breast cancer survivor.
PMID- 9765727
TI - The black box: physician response to breast cancer guidelines.
PMID- 9765728
TI - Silicone-gel-filled breast implants: how they interface with breast cancer. The
Working Group on Guidelines for Silicone Gel-Filled Breast Implants.
PMID- 9765729
TI - Tamoxifen and breast cancer prevention: are we aware of the risks?
PMID- 9765730
TI - Controversies in breast cancer screening.
PMID- 9765731
TI - Perspectives on Reach to Recovery and CanSurmount: informing the evaluation
model.
AB - The Canadian Cancer Society requested that the Centre for Behavioural Research
and Program Evaluation of the National Cancer Institute of Canada evaluate Reach
to Recovery and CanSurmount, 1-on-1 peer-support programs that provide
information and support to individuals with cancer and their families. Key
informant interviews (with program participants and volunteer visitors) were
conducted to gather qualitative data and to help us develop a framework and tools
to evaluate these programs. We found that 1) there are program objectives from
the perspective of volunteers and participants in addition to those outlined in
the program materials; 2) there are variations in how the programs are delivered
and how patients or family members are recruited into the program; and 3) there
is evidence that Reach to Recovery and CanSurmount volunteers are in a unique
position to deliver the programs, either because they have personally experienced
cancer or have family members who have had cancer. We describe the key informant
exercise developed for this evaluation project and present the results of
preliminary data-gathering activities.
PMID- 9765732
TI - Using Reiki to manage pain: a preliminary report.
AB - The purpose of this study was to explore the usefulness of Reiki as an adjuvant
to opioid therapy in the management of pain. Since no studies in this area could
be found, a pilot study was carried out involving 20 volunteers experiencing pain
at 55 sites for a variety of reasons, including cancer. All Reiki treatments were
provided by a certified second-degree Reiki therapist. Pain was measured using
both a visual analogue scale (VAS) and a Likert scale immediately before and
after the Reiki treatment. Both instruments showed a highly significant (p <
0.0001) reduction in pain following the Reiki treatment.
PMID- 9765734
TI - Psychosocial issues and life-cycle concerns of women with breast cancer.
PMID- 9765733
TI - Admissions to a radiation oncology inpatient service.
AB - PURPOSE: Although the care of inpatients is an important aspect of radiation
oncology practice in many countries, it has never been studied in detail. The
goal of this study was to describe the admissions to a radiation oncology
inpatient service over a 1-year period with respect to patient characteristics,
primary malignancies, common nonmalignant diagnoses, use of radiotherapy and
outcome of admission. METHOD: Using computerized hospital databases, we analysed
the utilization of 11 radiation oncology beds in a 424-bed teaching hospital from
March 31, 1991, to April 1, 1992. RESULTS: There were 342 admissions of 277
patients. The median age was 66.5 years; the male:female ratio was 1:1. The
commonest primary neoplastic diagnoses were lung (42%), gynecological (15%),
genitourinary (14%) and breast (8%) cancers. Only 17% of the patients had cancer
as the sole diagnosis; most patients had multiple medical diagnoses. Infections
(22%), neurological (20%), cardiovascular (13%) and endocrine (9%) conditions
were the commonest. Mean length of stay was 11.25 days. Most of the admissions
(71%) resulted in discharge to the patient's home; few patients (15%) died. Only
half of admissions involved radiotherapy, indicating that the focus of patient
care was the medical treatment of cancer complications or other active medical
problems. CONCLUSION: These data show that radiation oncology inpatients have
complicated medical problems, and they support the training of radiation
oncologists in the comprehensive medical care of patients.
PMID- 9765735
TI - Opportunities for research on prevention of breast cancer.
PMID- 9765736
TI - Information dissemination, access and informed consent: communications issues
discussed in the panel sessions of the National Forum on Breast Cancer.
PMID- 9765737
TI - Laying the groundwork for broadly based partnerships: the perceived influence of
the National Forum on Breast Cancer.
PMID- 9765738
TI - Factors associated with the use of mammography: the Ontario Health Survey.
PMID- 9765739
TI - Interaction between the breast cancer patient and the health care system:
demands, constraints and options for the future.
PMID- 9765741
TI - [Cancer of the breast, family functioning and adjustment to the disease].
PMID- 9765740
TI - Investigations for staging and follow-up of breast cancer patients.
PMID- 9765742
TI - Methodological problems in the epidemiology of dietary fat and breast cancer.
PMID- 9765743
TI - Spanning a continuum from cancer prevention amongst the entire healthy population
to the unique treatment.
PMID- 9765744
TI - An introduction to the framework project.
AB - The framework project of the Advisory Committee on Cancer Control (ACOCC),
National Cancer Institute of Canada (NCIC), was based on the NCIC/ACOCC
conceptual framework for bridging the gap between research and action. The
project was carried out under the auspices of the Sociobehavioural Cancer
Research Network (SCRN) of the NCIC. It focused on 3 research areas of cancer
control research: smoking control, palliative care and screening for breast
cancer. In this introductory paper, the criteria and methodology used for the
framework project are described, the main features of the framework are outlined
and the definitions of terms used in the framework are summarized. It was
expected that the framework project would lead to a better understanding of the
strengths and weaknesses of the NCIC/ACOCC conceptual framework. The project was
also expected to assist the SCRN in its ongoing efforts to develop and refine an
action-oriented research agenda.
PMID- 9765745
TI - School-based smoking control: a research agenda.
AB - Within the context of a framework for cancer control, this article reviews
evidence and suggests research directions for 3 types of school-based smoking
interventions: elementary school prevention, secondary school interventions and
interventions linking community and school. Directions for smoking research in
elementary schools include improving adoption through the provision of
effectiveness criteria, tailoring interventions to schools and training.
Monitoring at micro and macro levels may help planning and implementation, but
clearer evidence is required of its feasibility. Fundamental research should
explore new options to understand why youth do not start smoking. Smoking
intervention research at the secondary school level is less well established,
with only 1 effectiveness trial reported. We recommend testing models that
involve youth in developing their own solutions and examining the interaction of
various control measures. Sustainability issues have led researchers to embed
school-based smoking interventions in community-wide activities. Intervention
research of this sort still needs to determine how to apply approaches (e.g.,
comprehensive school health) and what the appropriate roles are (such as
technical assistance) for community agencies. All research using these school
community approaches needs to include process measures to explain potential
failures to obtain significant differences between components. In addition, we
call for research on the training of educators and health personnel, to increase
the priority given to smoking prevention and improve the implementation of
existing programs. Research on policy initiatives that lead to effective training
needs to be explored. Finally, we argue that application of the principles
incorporated into the cancer control framework (e.g., through participatory
research methods) strengthens the research process and results.
PMID- 9765746
TI - Promotion of breast cancer screening in communities: a research agenda.
AB - This paper used the National Cancer Institute of Canada (NCIC) cancer control
framework to review research on participation in breast cancer screening programs
and identify areas for further study. Cancer Lit, MEDLINE, CINAHL, Sociofile,
Health and the Public Affairs Information Service databases were searched for
literature published from 1990 to 1995. Information was also obtained from
provincial breast cancer screening programs and Health Canada. Interventions
designed to promote participation in screening programs have not been effective.
Involvement of the target community, however, increased success and
sustainability. Barriers to initial participation within screening programs
include alternative sources of screening and the lack of funds to screen all
eligible women. Studies show that participation decreases with successive
screening rounds. The priorities for study are development of: a theoretical
framework for recruitment strategies, a method to capture all Canadian screening
results including those performed through provincial health insurance plans and a
mechanism to deliver screening to all eligible Canadian women.
PMID- 9765747
TI - Focus groups with cancer patients: toward a more comprehensive understanding of
the cancer experience.
AB - Six focus groups of 58 individuals (30 women and 28 men) were held in 3 Canadian
cities to help develop a survey instrument to be implemented nationally to
identify cancer patients' experiences with cancer: treatment, symptoms and
symptom management. Patient participants had different cancer diagnoses, but
their experience with cancer had been within the year preceding the study. Our
intent was to identify as many themes as possible to allow for comparison of
different experiences in a national survey. This paper reports on what was
learned substantively from these focus groups and discusses the methodological
contribution of focus groups in developing survey tools.
PMID- 9765748
TI - Breast irradiation in women with early stage invasive breast cancer following
breast conservation surgery. Provincial Breast Disease Site Group.
AB - GUIDELINE QUESTIONS: 1) Should breast irradiation be given to women with early
stage invasive breast cancer (stage I and II) following breast conservation
surgery (lumpectomy with clear resection margins and axillary dissection)? 2) Is
there an optimal schedule for breast irradiation? 3) What is a reasonable
interval between definitive surgery and the start of breast irradiation? 4) Are
there patients who can be spared breast irradiation after lumpectomy? OBJECTIVE:
To make recommendations about the use of breast irradiation in women with early
stage invasive breast cancer following breast conservation surgery. OUTCOMES:
Local control is the primary endpoint of interest. Survival, quality of life
(addressed through the adverse effects of radiotherapy) and cosmesis are also
considered. PERSPECTIVE (VALUES): Evidence was selected and reviewed by 6 members
of the Breast Disease Site Group (Breast DSG) of the Ontario Cancer Treatment
Practice Guidelines Initiative. Earlier drafts of the evidence-based
recommendation were reviewed, discussed and approved by the Breast DSG, which
comprises medical oncologists, radiation oncologists, surgeons, epidemiologists,
pathologists and a medical sociologist. There was no participation by a community
representative in the development of this guideline. QUALITY OF EVIDENCE: There
are 5 randomized controlled trials (RCTs) and 1 meta-analysis comparing breast
irradiation with no breast irradiation following breast conservation surgery; 6
randomized trials comparing breast conservation surgery plus breast irradiation
with mastectomy are also included, as well as several retrospective studies.
BENEFITS: All of the 5 RCTs showed a significant decrease in local recurrence
rates among patients receiving radiotherapy. In the 4 trials with a median follow
up of 5 years or longer, the relative risk reduction with breast irradiation
ranged from 69% to 88%. The absolute differences ranged from 16% (p < 0.001) to
25% (p < 0.001). Despite the effect on local recurrence, no difference in
survival was detected in any of the 5 trials. Most of the patients with local
recurrence in these trials underwent mastectomy. HARMS: Major adverse effects of
breast irradiation occur very infrequently. PRACTICE GUIDELINE: Women with early
stage invasive breast cancer (stage I and II) who have undergone breast
conservation surgery should be offered postoperative breast irradiation. The
optimal fractionation schedule for breast irradiation has not been established,
and the role of boost irradiation is unclear. Outside of a clinical trial, 2
commonly used fractionation schedules are suggested: 50 Gy in 25 fractions to the
whole breast, or 40 Gy in 16 fractions to the whole breast with a local boost to
the primary site of 12.5 Gy in 5 fractions. Shorter schedules (e.g., 40 or 44 Gy
in 16 fractions) have also been used routinely in some centres. The enrollment of
patients in ongoing clinical trials is encouraged. Women who have undergone
breast conservation surgery should receive local breast irradiation as soon as
possible after wound healing. A safe interval between surgery and the start of
radiotherapy is unknown, but it is reasonable to start breast irradiation within
12 weeks after definitive surgery. For women who are candidates for chemotherapy,
the optimal sequencing of chemotherapy and breast irradiation is unknown. It is
reasonable to start radiotherapy after the completion of chemotherapy, or
concurrently if anthracycline-containing regimens are not used. For further
information, please refer to Ontario Cancer Treatment Practice Guidelines
Initiative's practice guideline "Surgical Management of Early Stage Invasive
Breast Cancer (stage I and II)."
PMID- 9765749
TI - Erythropoietin in the management of patients with nonhematologic cancer receiving
chemotherapy. Systemic Treatment Program Committee.
AB - GUIDELINE QUESTIONS: 1) Does erythropoietin (EPO) reduce the need for transfusion
of red blood cells in patients receiving chemotherapy for a nonhematologic
cancer? 2) Does the administration of EPO improve the quality of life of these
cancer patients? OBJECTIVE: To make recommendations regarding the use of EPO to
reduce the need for transfusion of red blood cells in patients receiving
chemotherapy for a nonhematologic cancer. OUTCOMES: First transfusion requirement
from the start of chemotherapy is the main outcome of interest. Quality of life
and costs are also considered. PERSPECTIVE (VALUES): Evidence was selected and
reviewed by 5 members of the Ontario Cancer Treatment Practice Guidelines
Initiative (OCTPGI) and the Systemic Treatment Program Committee (STPC). Drafts
of this document have been circulated to and reviewed by members of the STPC. The
STPC comprises medical oncologists, pharmacists, supportive care personnel and
administrators. No community representative participated in the development of
this practice guideline. QUALITY OF EVIDENCE: Eleven randomized controlled trials
(RCTs), most placebo-controlled, were available for review. A meta-analysis was
performed with 8 trials that shared a clinically relevant outcome measure. Only 1
trial assessed quality of life. BENEFITS: The meta-analysis showed a relative
risk for transfusion among EPO patients of 0.64 (95% confidence interval 0.53
0.78), which translates into a 36% relative reduction in the proportion of
patients requiring transfusion (p = 0.00001). Reduction in transfusion
requirements was similar across strata defined by methodological quality, EPO
dose, hematologic status, tumour type at trial entry and chemotherapy regimen. In
the 1 trial that assessed quality of life, EPO was associated with improved
quality of life. HARMS: Hypertension has been noted rarely in EPO-treated cancer
patients. The RCTs did not report adverse effects in EPO-treated patients
compared with control patients during the follow-up period. Long-term adverse
effects are unknown. EPO is more costly than transfusion, but formal cost
effectiveness studies are unavailable. PRACTICE GUIDELINE: For patients receiving
chemotherapy for nonhematologic cancer in whom symptoms of anemia are expected
and in whom transfusion of red blood cells is not considered an acceptable
treatment option, EPO can be recommended as a safe, effective treatment
alternative. The evidence in support of using EPO is stronger for patients
receiving platinum-based chemotherapy regimens that for those receiving non
platinum-based regimens. CLINICAL PRACTICE GUIDELINE DATE: Apr. 4, 1997.
PMID- 9765750
TI - Unresected stage III non-small-cell lung cancer. Provincial Lung Cancer Disease
Site Group.
AB - GUIDELINE QUESTIONS: 1) What is the role of different schedules or doses of
radiotherapy in patients with unresected, clinical or pathological, stage III non
small-cell lung cancer (NSCLC)? 2) Does chemotherapy combined with radiotherapy
provide improved survival compared with radiotherapy alone in patients with
unresected NSCLC? OBJECTIVE: To make recommendations about the role of
chemotherapy and radiotherapy in the treatment of unresected stage III NSCLC.
OUTCOMES: Survival is the primary outcome of interest. Quality of life is a
secondary outcome. PERSPECTIVE (VALUES): Evidence was selected and reviewed by 5
members of the Provincial Lung Cancer Disease Site Group (Lung DSG) of the
Ontario Cancer Treatment Practice Guidelines Initiative. The Lung DSG comprises
medical and radiation oncologists, pathologists, surgeons, epidemiologists, a
psychologist and a medical sociologist. No community representative participated
in the development of this guideline. QUALITY OF EVIDENCE: Two meta-analyses were
available for review. The specific analysis of interest examined the role of
combined chemotherapy plus radiotherapy v. radiotherapy alone in locally advanced
disease. The first meta-analysis included combined data from 22 randomized
controlled (RCTs) involving a total of 3033 patients. The second included
combined data from 14 RCTs involving a total of 2589 patients. Also reviewed were
4 RCTs of radiotherapy alone, 1 trial of combined chemotherapy and radiotherapy
that was not included in the meta-analysis, 4 abstracts of studies of combined
chemotherapy and radiotherapy, and 4 trials examining the role of
hyperfractionated radiotherapy. BENEFITS: In the first meta-analysis, an overall
benefit was detected at 2 years for the use of combined chemotherapy and
radiotherapy. A hazard ratio of 0.90 (p = 0.006), or a 10% reduction in the risk
of death, translated into an absolute benefit of 3% at 2 years and 2% at 5 years.
A subgroup analysis of cisplatin-based chemotherapy plus radiotherapy versus
radiotherapy alone demonstrated a 13% reduction in the risk of death in the
combined treatment arm (pooled hazard ratio 0.87, 95% confidence interval [CI]
0.79-0.96), for an absolute benefit of 4% at 2 years. In the second meta
analysis, there was a 13% reduction in the risk of death in the combined therapy
arm at 2 years (pooled relative risk [RR] 0.87, 95% CI 0.81-0.94) and a 17%
reduction at 3 years (pooled RR 0.83, 95% CI 0.77-0.90). Subgroup analysis of
cisplatin-based chemotherapy plus radiotherapy versus radiotherapy alone showed
similar results: a 15% reduction in the risk of death in the combined therapy arm
at 2 years (pooled RR 0.85, 95% CI 0.79-0.92) and a 19% reduction at 3 years
(pooled RR 0.81, 95% CI 0.74-0.88). PRACTICE GUIDELINE: For patients with
unresected stage III NSCLC, the combination of cisplatin-based chemotherapy and
radical radiotherapy provides a survival benefit compared with radiotherapy
alone. This guideline is based on high-quality evidence from 2 meta-analyses of
RCTs. Patients with good performance status (Eastern Cooperative Oncology Group
[ECOG] 0-1) and minimal weight loss (less than 5% in the preceding 3 months) have
been shown to have a survival benefit from treatment with combined chemotherapy
and radiotherapy and should be considered for this type of treatment approach
(see section V). For these patients, thoracic irradiation of 60 Gy in 30
fractions over 6 weeks, in combination with cisplatin-based chemotherapy, should
be recommended as a treatment option. The patient and physician should discuss
fully the benefits, limitations and toxic effects of therapy. Patients not
meeting these criteria are not candidates for combined therapy; those
experiencing symptoms amenable to treatment should receive palliative thoracic
irradiation. At this time, hyperfractionated radiotherapy is not recommended
outside of the context of a clinical trial. (ABSTRACT TRUNCATED)
PMID- 9765751
TI - Increasing demands to consider both the benefits and costs of cancer treatment in
decision relating to resource allocation.
PMID- 9765752
TI - A comparison of the costs of paclitaxel and best supportive care in stage IV non
small-cell lung cancer.
AB - PURPOSE: To compare the expenditures associated with single-agent paclitaxel
(Taxol) with those of best supportive care as treatment for stage IV non-small
cell lung cancer (NSCLC). METHODS: The primary data sets of 2 phase II trials of
paclitaxel in advanced NSCLC were obtained. Paclitaxel delivery costs were
estimated at the Ottawa Regional Cancer Centre using the mean paclitaxel dose
from the 2 phase II trials, 214 mg/m2, a 3-week schedule and a median of 3
treatment cycles. Data regarding dosage, costs and survival were incorporated
into the Statistics Canada POpulation HEalth Model (POHEM), which generated
hypothetical cohorts of patients treated either with best supportive care or
paclitaxel. The POHEM model assigned diagnostic workup, treatment, disease
progression and survival characteristics to each of these cohorts and tabulated
the costs associated with each. RESULTS: The total cost of administering 3 cycles
of chemotherapy was Can$8143 per patient. The strategy of treating NSCLC patients
with paclitaxel cost $3375 more per patient than best supportive care. On the
basis of the difference in survival duration between stage IV patients treated in
the best supportive care arm of a previous National Cancer Institute of Canada
trial and those represented in the pooled phase II survival results, the cost per
life-year saved was $4778. For sensitivity analyses, the days of hospitalization
for terminal care, number of cycles given and survival benefit produced were
varied. The sensitivity analysis produced a cost per life-year saved of up to
$21,377 under the least favourable assumptions. CONCLUSION: If large phase III
trials confirm the survival benefits observed in the phase II trials, paclitaxel
can be considered to be a cost-effective agent in the management of advanced
NSCLC.
PMID- 9765753
TI - A critical review of research related to family physician-assisted smoking
cessation interventions.
AB - A review of family physician-assisted smoking cessation research indicates that
the family practice setting affords an excellent opportunity to intervene with a
large proportion of smokers, at a time when they are receptive to health
promotion messages. Outcome data at 6- and 12-month follow-up intervals indicate
the value of combining 3 key strategies in achieving optimal results: physician
advice and support, nicotine replacement therapy, and cognitive-behavioural
counselling. The authors' review identifies questions that need to be addressed
in future research: How can barriers to program delivery be overcome in the
family practice setting? What is the best way to ensure optimal integration of
the 3 key strategies? Which follow-up intervals are appropriate (e.g., 6 months,
12 months, 18 months) given the finding that relapse is common and that most
smokers make several quit attempts before stopping for good?
PMID- 9765754
TI - Adjuvant therapy for stage III colon cancer after complete resection. Provincial
Gastrointestinal Disease Site Group.
AB - GUIDELINE QUESTIONS: Should patients with resected stage III colon cancer receive
adjuvant therapy? If so, which therapy should be recommended? OBJECTIVE: To make
recommendations regarding the use of adjuvant therapy in the treatment of
resected stage III colon cancer. OUTCOMES: Overall survival is the primary
outcome of interest. Secondary outcomes are disease-free survival and adverse
effects of the treatment regimens. PERSPECTIVE (VALUES): Evidence was selected
and reviewed by 4 members of the Gastrointestinal Disease Site Group (GI DSG) of
the Ontario Cancer Treatment Practice Guidelines Initiative. Earlier drafts of
the guideline were reviewed, discussed and approved by the GI DSG, which
comprises medical and radiation oncologists, surgeons and epidemiologists.
Community representatives did not participate in the development of this
guideline but will participate in future guidelines development. QUALITY OF
EVIDENCE: There are 3 meta-analyses, 33 published randomized controlled trials
(RCTs) and 1 consensus statement. The GI DSG pooled data from 10 of the 33 RCTs
that allowed for such an analysis. BENEFITS: Two of 3 RCTs reported improved
survival rates with 5-fluorouracil (5-FU) plus semustine or mitomycin C (MMC)
compared with no treatment (observation) after surgical resection. Three trials
reported a benefit in both overall and disease-free survival with 5-FU plus
levamisole compared with observation after surgery. In 2 trials, levamisole alone
did not produce a survival benefit compared with observation. One trial reported
improved disease-free, but not overall, survival rates with oral HCFU (1
hexylcarbamoyl-5-fluorouracil) compared with observation. In 3 trials of 5-FU
plus leucovorin, disease-free and overall survival rates were improved compared
with observation. Nine trials compared portal vein infusion (PVI) of 5-FU with
observation after surgery. In 2 of the trials, for which data were available for
stage III patients only, improved overall survival was reported. There was a
trend in all studies favouring PVI. One trial reported a survival benefit for
stage III and IV patients who received oral HCFU maintenance therapy for 1 year
compared with no maintenance therapy. In a trial comparing MMC plus oral HCFU
with MMC alone, a survival benefit was reported in the combined treatment group;
however, the stages of cancer were unevenly distributed among the treatment
groups. Only 1 study tested monoclonal antibody; a benefit was reported for both
overall and disease-free survival. A meta-analysis of 10 trials comparing
adjuvant therapy with observation in patients with stage III disease detected a
significant reduction in the odds ratio (OR) for death (OR 0.69; 95% confidence
interval [CI] 0.57 to 0.85), with an absolute improvement in survival of 4% to
13%. When trials were separated according to the type of treatment given, the
significant ORs were for 5-FU plus either levamisole (OR 0.61; 95% CI 0.46 to
0.80) or leucovorin (OR 0.51; 95% CI 0.36 to 0.73). Three recently reported
trials comparing various combinations of 5-FU plus leucovorin, with or without
levamisole, showed similar improvements in disease-free and overall survival.
PMID- 9765755
TI - Well-being at the end of life: Part 1. A research agenda for psychosocial and
spiritual aspects of care from the patient's perspective.
AB - This article reviews the scientific literature concerning psychosocial and
spiritual aspects of palliative care for the patient with cancer. It discusses 4
separate areas: the continuum of care, communication, spiritual and psychological
issues, and psychotherapeutic and behavioural management of physical symptoms.
Most of the research could be classified as fundamental according to the Cancer
Control Framework of the National Cancer Institute of Canada. In some areas, even
fundamental research was lacking. There is a need for clearer and more relevant
definitions of the desired outcomes of interventions and also for the development
of appropriate quantitative and qualitative methods. We must determine which
interventions can be initiated earlier in the disease trajectory and can provide
benefit at the palliative phase. Given the burden of suffering that palliative
care aims to address, relatively little research in this area has been conducted.
PMID- 9765756
TI - Well-being at the end of life: Part 2. A research agenda for the delivery of care
from the patient's perspective.
AB - This article reviews the scientific literature in several areas important to the
delivery of palliative care: multicultural issues, education, comprehensive
outcome measures and ethics. Most of the research can be classified as
fundamental rather than intervention research according to the Cancer Control
Framework of the National Cancer Institute of Canada. Desired outcomes of
interventions are most often defined from the health care professional's
perspective but need to be defined from the patient's perspective. In areas such
as multicultural issues and the effect of the volunteer on the patient, there is
almost no research. The complexity of studying the best way to deliver palliative
care would benefit from the input of colleagues who have experience addressing
these issues in other patient populations.
PMID- 9765757
TI - Family health and the palliative care trajectory: a cancer research agenda.
AB - This article reviews the published literature related to families of palliative
care patients with cancer within the context of the Cancer Control Framework of
the National Cancer Institute of Canada. Three themes emerged: 1) the impact of
terminal cancer on the family; 2) family functioning--responses to terminal
cancer; and 3) quality of palliative care from the family perspective. The most
substantial body of research describes family needs, family caregiving burdens,
caregiving costs and the impact of the patient's terminal cancer on the health of
family members. Small samples, high nonresponse rates, selection biases and a
lack of standardized outcome measures have impeded the advancement of knowledge.
Method development studies are warranted, including the development of
instruments to measure family care constructs. Longitudinal studies to examine
the long-term impact of the patient's functional status, mood, symptom distress
and quality of life on family members are needed. Research should also explore
the effects of family composition, socioeconomic factors, culture and
spirituality on families' experiences with terminal illness. Identification of
families at risk as well as development and rigorous testing of appropriate
interventions should become priorities.
PMID- 9765758
TI - Critique of the National Cancer Institute of Canada's framework for cancer
control.
AB - This paper offers a critique of the National Cancer Institute of Canada's (NCIC)
framework for cancer control. The critique has been prepared by researchers who
used the framework to review the literature in 5 substantive areas. These
reviews, published in the current and previous issues of CPC, were designed to
begin to outline a research agenda for the Sociobehavioural Cancer Research
Network. In this paper, the authors reflect on the strengths and limitations of
the framework. Perceived strengths are that the framework (a) facilitates
systematic thinking about research options and priorities, (b) helps foster clear
communication, (c) links science and practice, (d) may assist grant review panels
to place proposed studies in context and (e) emphasizes important values.
Perceived concerns include the following: (a) potential users are not familiar
with the framework, (b) lack of clarity of definitions and classification
criteria, (c) the utility of the framework is not immediately self-evident to
potential users, (d) the framework lacks emphasis on environmental and policy
interventions and (e) it is not clear how the values espoused are to be
integrated with other dimensions of the framework. The concerns were seen as
remediable. In short, the framework was seen to be valuable in its current form;
refinement may enhance its value.
PMID- 9765759
TI - Adjuvant radiotherapy and chemotherapy for stage II or IIIA non-small-cell lung
cancer after complete resection. Provincial Lung Cancer Disease Site Group.
AB - GUIDELINE QUESTIONS: 1) Does the use of postoperative, adjuvant radiotherapy or
chemotherapy, alone or in combination, improve survival rates among patients with
completely resected, pathologically confirmed stage II or IIIA non-small-cell
lung cancer (NSCLC)? 2) Does the use of radiotherapy reduce the risk of local
recurrence among patients with completely resected stage II or IIIA NSCLC?
OBJECTIVE: To make recommendations about the use of postoperative adjuvant
radiotherapy and chemotherapy in the treatment of patients with completely
resected stage II or IIIA NSCLC. OUTCOMES: Overall survival and disease-free
survival are the primary outcomes of interest. A secondary outcome of interest is
local disease control. PERSPECTIVES (VALUES): Evidence was collected and reviewed
by 4 members of the Lung Cancer Disease Site Group (Lung Cancer DSG) of the
Cancer Care Ontario Practice Guidelines Initiative. The evidence-based
recommendation resulting from this review was approved by the Lung Cancer DSG,
which comprises medical oncologists, radiation oncologists, pathologists,
surgeons and a medical sociologist. A community representative was present at 1
meeting during which the recommendation was discussed. QUALITY OF EVIDENCE: One
meta-analysis and 22 randomized controlled trials (RCTs) were published between
1962 and 1996. The RCTs compared surgery plus radiotherapy with surgery alone;
surgery plus adjuvant chemotherapy with surgery alone; surgery plus radiotherapy
with surgery plus both chemotherapy and radiotherapy. Many studies included
patients with stage IIIB NSCLC; some included patients with incompletely resected
stage I NSCLC or with small cell lung cancer (maximum 10%). Older studies used
chemotherapy or radiation that would now be considered inferior according to
current standards of practice. BENEFITS: There was no survival benefit with
adjuvant radiotherapy alone, although 3 RCTs reported a reduction in the rate of
local recurrence among patients treated with adjuvant radiotherapy. The meta
analysis showed that postoperative, cisplatin-based chemotherapy alone reduced
the relative risk of death by 13% (hazard ratio [HR] 0.87, 95% confidence
interval [CI] 0.74 to 1.02); in combination with radiotherapy it resulted in a 6%
reduction in the relative risk of death (HR 0.94, 95% CI 0.79 to 1.11). HARMS:
Postoperative adjuvant chemotherapy with alkylating agents was found in the meta
analysis to increase the relative risk of death by 15%. A study involving
prolonged adjuvant chemotherapy (busulfan or cytoxan daily for 2 years) reported
that 4 of 726 patients had hematologic malignancies. In 1 study, only 53% of
patients received all 4 cycles of chemotherapy with cyclophosphamide-doxorubicin
cisplatin (CAP); in another, 22% of patients refused therapy with CAP because of
nausea and vomiting. PRACTICE GUIDELINE: There is evidence from RCTs that
postoperative radiotherapy reduces rates of local recurrence by 11% to 18% (or
1.6 to 19-fold) among patients with completely resected, pathologically confirmed
stage II or IIIA NSCLC. Therefore, if the outcome of interest is a reduction in
the frequency of local tumour recurrence, radiotherapy is recommended. However,
there is no evidence of a survival benefit from postoperative radiotherapy alone.
In a meta-analysis, postoperative chemotherapy with or without radiotherapy
resulted in a slightly reduced (statistically nonsignificant) risk of death among
patients with surgically resected stage II or IIIA NSCLC. The survival benefit
was small and achieved only with chemotherapy regimens that produced substantial
toxic effects and that are no longer used. Newer chemotherapy regimens are
currently being evaluated as adjuvant therapy, but there is insufficient evidence
of benefit at this time to recommend them. Therefore, if the outcome of interest
is survival, there is insufficient evidence to recommend current chemotherapy
regimens with or without radiotherapy as postoperative, adjuvant the
PMID- 9765760
TI - Adjuvant therapy for stage II colon cancer after complete resection. Provincial
Gastrointestinal Disease Site Group.
AB - GUIDELINE QUESTION: Should patients with resected stage II colon cancer receive
adjuvant therapy? OBJECTIVE: To make recommendations regarding the use of
adjuvant therapy in the treatment of resected stage II colon cancer. OUTCOMES:
Overall survival is the primary outcome of interest. Secondary outcomes are
disease-free survival and adverse effects of the treatment regimens. PERSPECTIVE
(VALUES): Evidence was selected and reviewed by 2 members of the Provincial
Gastrointestinal Disease Site Group (GI DSG) of the Cancer Care Ontario Practice
Guidelines Initiative. The recommendations resulting from this review have been
approved by the GI DSG, which comprise medical and radiation oncologists,
surgeons and epidemiologists. Community representatives did not participate in
the development of this practice guideline but will do so in future guidelines
development. QUALITY OF EVIDENCE: There are 25 published randomized controlled
trials (RCTs) and 1 meta-analysis. The GI DSG pooled data from 11 of the 25 RCTs
that provided adequate data. BENEFITS: The 25 RCTs are grouped according to the
type of therapy and whether the control patients received no treatment
(observation) or other adjuvant therapy after resection. Because the trials
usually included patients with stage II and III cancer, the complete trial
results and those for a subset of patients with stage II disease were analysed.
Although the overall trial results showed a survival benefit for adjuvant
treatments, the benefit was not significant for stage II patients. A meta
analysis of 11 trials comparing adjuvant treatment with observation in patients
with stage II cancer indicated no significant reduction in the odds ratio (OR)
for death (OR 0.83; 95% confidence interval [CI] 0.62 to 1.10). The OR for death
among patients receiving chemotherapy by portal vein infusion (PVI) was 0.62 (95%
CI 0.35 to 1.11). HARMS: The toxic effects of 5-fluorouracil (5-FU) with either
levamisole or leucovorin, or both, were mild to moderate and consisted mostly of
stomatitis, diarrhea and myelosuppression; 5% of patients required hospital
admission. 5-FU plus levamisole was associated with transient neurotoxic effects
in 18% of patients. Toxic effects associated with PVI were mild, rare and mostly
consisted of leukopenia and diarrhea; 1% of patients experienced bowel
perforation. PRACTICE GUIDELINE: Adjuvant therapy is not recommended at this time
for the routine management of patients with resected stage II colon cancer.
Patients with stage II disease and high-risk factors (bowel obstruction, tumour
adhesion, invasion, perforation or aneuploidy) have a poorer prognosis, similar
to that of patients with stage III colon cancer. For individual management, these
patients should be made aware of their prognosis; treatment can be considered
after the uncertainty of the value of adjuvant therapy has been explained to the
patient. The enrolment of patients with high-risk stage II disease in clinical
trials is encouraged. Trials comparing adjuvant therapy with observation are
needed and are ethically acceptable in stage II colon cancer.
PMID- 9765761
TI - Critical review of 5 nonpharmacologic strategies for managing cancer pain.
AB - PURPOSE: Health care professionals at 2 Ontario cancer centres were surveyed to
determine their familiarity with, perceptions of and interest in learning more
about nonpharmacologic strategies for the management of cancer pain. Evidence
based education sessions were subsequently developed for the 5 strategies in
which participants were most interested. This article presents the results of
critical literature reviews concerning the effectiveness of the 5 strategies:
acupuncture, massage therapy, hypnosis, therapeutic touch and biofeedback.
METHODS: The databases MEDLINE (1966 to June 1997), CINAHL (1982 to June 1997)
and PsychoINFO Lit (1980 to June 1997) were searched systematically for
randomized controlled trials (RCTs) of the 5 nonpharmacologic strategies. The
authors' personal files and reference lists of relevant papers and main texts
were also searched. The quality of the trials was reviewed according to
established criteria. RESULTS: The search yielded 1 RCT of acupuncture, 1 of
massage therapy and 6 of hypnosis. The studies of hypnosis suggested that there
is much support for its use in the management of cancer pain. The evidence was
either lacking or less clear for the other therapies examined. CONCLUSION:
Because patients use a wide variety of nonpharmacologic strategies regardless of
their effectiveness, clinicians need to be familiar with available research and
able to discuss those strategies for which the evidence is strong, weak or
nonexistent. More research on the effectiveness of nonpharmacologic strategies
for pain management is needed.
PMID- 9765763
TI - Atlantic Breast Cancer Information Project: formation of a "town-gown"
partnership.
AB - The Atlantic Breast Cancer Information Project (ABCIP) is one of 5 breast cancer
information exchange projects funded by Health Canada. This article describes the
development of ABCIP and thereby contributes to the limited knowledge on
successful partnership formation in the face of restraints but with support from
enabling factors. Partnership formation is presented in the context of alliances
in management, coalitions in health promotion, and social movements. The
restraining factors were the inertia of the status quo, provincial structures and
concerns about empowering others. The enabling factors fell into 3 categories:
timely logistics, roles of individuals who participated at critical points in the
process, and the evolution of a supportive cultural environment. The article
outlines ABCIP's achievements to date.
PMID- 9765762
TI - Survival rates among Canadian children and teenagers with cancer diagnosed
between 1985 and 1988.
AB - PURPOSE: To describe the survival rates among Canadian children and teenagers
with cancer diagnosed between 1985 and 1988 using population-based data,
specifically for the more common forms of childhood cancer, and to assess the
effect of age at diagnosis and sex as prognostic factors for selected childhood
cancers. DESIGN: Retrospective survival study based on incident cases of cancer
identified by the National Cancer Incidence Reporting System and follow-up
ascertained by computer record linkage to the Canadian Mortality Database.
SUBJECTS: A total of 4409 patients with cancer first diagnosed at 19 years of age
or younger between 1985 and 1988, and followed up to Dec. 31, 1991. MAIN OUTCOME
MEASURES: Survival rates calculated at 1, 3 and 5 years according to the
actuarial life table and the proportional hazards models. RESULTS: The 5-year
survival rate for all cancers combined was 71%. Females with acute lymphoblastic
leukemia and astrocytoma had markedly higher survival rates than their male
counterparts (p < 0.05). Age at diagnosis was a significant predictor of survival
among children with acute lymphoblastic leukemia or acute nonlymphoblastic
leukemia (p < 0.01), infants having a substantially poorer prognosis than older
children. Conversely, the survival rate among infants with neuroblastoma was
higher than that among older children, 87% surviving for 5 years after diagnosis.
CONCLUSIONS: The survival rate among Canadian children and teenagers with cancer
is favourable in relation to the rate among adults with cancer. Nonetheless, the
5-year survival rates for several childhood cancers remain poor (i.e., less than
65%). The survival rates among Canadian children with cancer are similar to those
among children with cancer in other developed countries.
PMID- 9765765
TI - Information needs of women with metastatic breast cancer.
AB - Eight focus groups involving women with metastatic breast cancer were held across
Ontario over approximately 6 months in 1996-97. Prevalent themes identified
during the sessions are reported under 2 broad dimensions: the women's expressed
desire for information in specific content areas, and issues related to whether
information can be either beneficial or harmful, depending on how it is provided.
The women reported high needs for information, especially that which would relate
to their situation. Perceived adequacy of information is closely linked to health
professional engagement and care. Although the provision of information is
important, the needs of these women for maintenance of hope and provision of
interpersonal support and comfort are also critical.
PMID- 9765764
TI - Use of preoperative chemotherapy with or without postoperative radiotherapy in
technically resectable stage IIIA non-small-cell lung cancer. Provincial Lung
Cancer Disease Site Group.
AB - GUIDELINE QUESTION: Should preoperative (neoadjuvant) cisplatin-based
chemotherapy with or without postoperative radiotherapy be offered to patients
with technically resectable stage IIIA non-small-cell lung cancer (NSCLC) to
improve survival? (Resectability should be determined preoperatively by a
thoracic surgeon.) OBJECTIVE: To make recommendations about the use of
preoperative cisplatin-based chemotherapy with or without postoperative
radiotherapy in technically resectable stage IIIA NSCLC. OUTCOMES: Survival is
the primary outcome of interest. PERSPECTIVES (VALUES): Evidence was collected
and reviewed by 4 members of the Lung Cancer Disease Site Group (LCDSG) of the
Cancer Care Ontario Practice Guidelines Initiative. The evidence was then
presented to the full LCDSG and discussed extensively at 5 of its meetings. The
LCDSG comprises medical and radiation oncologists, pathologists, surgeons,
epidemiologists, a psychologist and a medical sociologist. A community
representative was present at one meeting during which the recommendation was
discussed. QUALITY OF EVIDENCE: Four small randomized controlled trials (RCTs)
were available for review; 2 were completed and were reported in full in the
literature, 1 was published in abstract form, and 1 was closed and was reported
as an interim analysis. Although the RCTs used appropriate clinical trials
methodology, including planned interim analyses and early stopping rules,
retrospective review revealed inconsistencies between the treatment arms for
subsets of stage IIIA disease and for prognostic factors. These factors and the
small samples in each study limit the interpretation of the results. BENEFITS:
The data from 2 of the 4 trials were not combined because the data were not
mature in one case and not extractable in the other. The 2 fully published,
completed trials reported a survival benefit for patients treated with
preoperative chemotherapy with or without postoperative radiotherapy compared
with those not given preoperative chemotherapy. One trial reported a median
survival of 26 months in the treatment group versus 8 months in the control group
(p < 0.001). A second trial reported an estimated median survival of 64 months
versus 11 months (p < 0.008) and a 3-year survival rate of 56% versus 15%
respectively. A pooled analysis of the 2-year survival data from the 2 completed
RCTs yielded an odds ratio for death of 0.18 (95% confidence interval 0.06 to
0.51) in favour of preoperative chemotherapy. HARMS: There was no difference in
the postoperative mortality between the trials reviewed. Toxic effects associated
with the chemotherapy were limited primarily to neutropenic fever, nausea and
vomiting.
PMID- 9765766
TI - Follow-up practices for patients with early stage breast cancer: a survey of
Canadian oncologists.
AB - The value of routine follow-up programs for patients with early stage breast
cancer remains an area of controversy. In recent years, the cost-effectiveness of
routine investigations has been questioned, and 2 prospective randomized clinical
trials have shown no survival advantage to more intensive diagnostic follow-up
approaches. Under the auspices of the Ottawa Regional Cancer Centre, a national
survey of the practice patterns of Canadian surgical, radiation and medical
oncologists was undertaken to measure current Canadian standards of care and to
determine average costs of 5-year follow-up for patients completing primary
treatment for stage I and II breast cancer. Standardized questionnaires were sent
out to 130 surgeons, 59 radiation oncologists and 89 medical oncologists. The
overall response rate was 44%. Based on the frequency of follow-up visits and
investigations recommended by respondents, an average cost per patient for a 5
year follow-up plan was derived for each subspecialist group: $791, $911 and $904
for surgeons, radiation oncologists and medical oncologists respectively. Use of
a less interventionist follow-up program was estimated to result in a cost saving
of $300 per patient over 5 years. The results indicate that, for the most part,
Canadian oncologists have been influenced by the available literature concerning
follow-up practices and are ordering fewer routine tests. Further cost savings to
the Canadian health care system could be achieved with the adoption of even less
interventionist follow-up programs.
PMID- 9765767
TI - Effectiveness of megestrol acetate in patients with advanced cancer: a
randomized, double-blind, crossover study.
AB - PURPOSE: To evaluate the effect of megestrol acetate at a lower dose than
previously investigated on the symptoms of cachexia in patients with advanced
cancer. METHODS: A total of 84 patients with advanced, solid tumours not
responsive to hormone therapy were enrolled in this double-blind, crossover
study. During phase 1, patients were randomly assigned to receive megestrol
acetate (160 mg 3 times daily) for 10 days or placebo. During phase 2, after a 2
day washout period, patients received the alternate treatment for 10 days.
Patients underwent daily assessments of activity, nausea, appetite and well-being
by means of a visual analogue scale (VAS). In addition, nutritional status
(weight, tricep skinfold measure, arm muscle circumference), energy intake,
fatigue (Piper Fatigue Scale) and quality of life (Functional Living Index-Cancer
[FLIC]) were assessed. RESULTS: Among the 53 evaluable patients megestrol acetate
resulted in a significant improvement in appetite (p = 0.005), activity (p =
0.007) and well-being (p = 0.03). There was no significant change in the
intensity of nausea, nutritional parameters, energy intake or FLIC scores. There
was a significant improvement in 2 of the 3 factors measured by the Piper Fatigue
Scale and in the overall fatigue score. Upon completion of the study, while still
blind to the treatment condition, 30 patients indicated that they felt better
overall after megestrol, 15 said they felt better after placebo, and 10 indicated
no preference (p = 0.001). CONCLUSION: Treatment with megestrol acetate results
in rapid and significant improvement of symptoms in terminally ill patients at
lower doses than previously reported. The effects are not secondary to
nutritional changes. The FLIC quality-of-life questionnaire was unable to detect
these changes.
PMID- 9765768
TI - Use of strontium-89 in endocrine-refractory prostate cancer metastatic to bone.
Provincial Genitourinary Cancer Disease Site Group.
AB - GUIDELINE QUESTION: What is the role of strontium-89 in effective palliative care
of patients with stage D endocrine-refractory prostate cancer and multiple sites
of painful bone metastases? OBJECTIVE: To make recommendations about the routine
use of 89Sr in this clinical setting. OUTCOMES: Effective palliation is the
primary outcome of interest. Patient survival and toxic effects of treatment are
also considered. PERSPECTIVE (VALUES): Evidence was selected and reviewed by 3
members of the Genitourinary Cancer Disease Site Group (Genitourinary Cancer DSG)
of the Cancer Care Ontario Practice Guidelines Initiative. Earlier drafts of the
guideline were circulated and reviewed by members of the DSG. The Genitourinary
Cancer DSG comprises medical oncologists, radiation oncologists, urologists, a
pathologist and a community representative. Guideline approval requires input
from community representatives. QUALITY OF EVIDENCE: Three randomized controlled
trials (RCTs) were available for evaluation. Two compared 89Sr with placebo, and
one RCT compared 89Sr with conventional radiation (either hemibody or involved
field radiotherapy, as determined before randomization). BENEFITS: One of the 2
studies comparing 89Sr with placebo demonstrated the palliative efficacy of the
intervention (p < 0.01); the other showed no benefit. The third study, comparing
89Sr with conventional radiation, concluded that all treatments provided equally
effective pain relief and that improvement was sustained for at least 3 months in
similar proportions of patients. The difference in the median duration of patient
survival between groups in this study was neither clinically nor statistically
significant. HARMS: The use of 89Sr may cause bone marrow suppression, but
clinically significant sequelae are uncommon. The use of 89Sr may preclude
further systemic chemotherapy or eligibility for clinical trials of systemic
therapy. Symptoms other than those due to bone marrow suppression are rare.
PRACTICE GUIDELINE: 89Sr is recommended for use in patients with endocrine
refractory prostate cancer who have multiple uncontrolled painful sites of bone
metastases on both sides of the diaphragm not adequately controlled with
conventional analgesic therapy, and in whom the use of multiple single fields of
external beam radiation is not possible. 89Sr has proven to be efficacious in the
palliation of hormone-refractory painful bone metastases from prostate cancer. It
has not been shown to lengthen the average duration of patient survival. There is
limited evidence on the relative efficacy of 89Sr compared with wide-field
radiotherapy. 89Sr is the treatment of choice given all the following specific
indications: Established diagnosis of prostate cancer metastatic to bone.
Metastatic disease refractory to hormone therapy. Progressive sites of pain
poorly controlled with conventional narcotics. Painful sites of disease on both
sides of the diaphragm (otherwise, hemibody radiotherapy is equally efficacious).
Patient or tumour factors (number of involved sites, location of involved sites
or level of pain control) that are relative contraindications to the use of
multiple single fields of radiation as an alternative. No evidence of impending
spinal cord compression. Adequate bone marrow reserve. Evidence from a diagnostic
bone scan of radionuclide concentration in painful bone lesions. PRACTICE
GUIDELINE DATE: Nov. 23, 1997. Part 2. GUIDELINE QUESTION: What is the role of
89Sr in effective palliative care of patients with stage D hormone-refractory
prostate cancer receiving involved-field radiotherapy for isolated painful bone
metastases? OBJECTIVE: To make recommendations about the routine use of 89Sr in
this clinical setting. OUTCOMES: Effective palliation is the primary outcome of
interest. Patient survival and toxic effects of treatment are also considered.
PERSPECTIVE (VALUES): As described in preceding abstract (Part 1). QUALITY OF
EVIDENCE: One RCT was available for evaluati
PMID- 9765769
TI - [Continent urostomy: sigmoid reservoir and sigmoid hydraulic valve].
AB - We report our experience of continent sigmoidostomy. The technique consisted in
urinary diversion with sigmoid pouch and hydraulic valve. Eleven patients
underwent this procedure (10 men and 1 women, mean age 48 years, range 20 to 77
years). Indications were bladder tumor in 7 cases, bladder exstrophy in 2
patients, neurogenic bladder in 1 case and 1 bladder with a small capacity
secondary to a stricture of traumatic urethra. The pouch was made according to
the detubularized model. The sigmoid was opened on its antimesenteric edge,
leaving the distal portion of the sigmoid intended to do the sigmoid valve. The
posterior edges of the colonic segment opened were alined then secured by a Dexon
3/0 whipping then the anterior adges were secured, as the former after
reimplantation of the ureters according to Camey Leduc or Politano Leadbetter's
procedure. The post operative follow-up was marked by a fistula of the pouch in
one case treated by securing it. All the patients were continent day and night.
The purpose of this study was the description of the technique and the results of
the continent sigmoidostomy.
PMID- 9765770
TI - [Salvage therapy with anti-IL-2 receptor antibodies in high-risk kidney
transplant patients].
PMID- 9765771
TI - [Urethral lengthening (the Kropp technic) in neurologic urinary incontinence in
children and adolescents. Results of a series of 22 cases].
AB - In 1986 Kropp et Angwafo described a technique of urethral lengthening for the
treatment of urinary incontinence in children with neurogenic bladders. We have
used a modified version of this procedure in 22 girls between 1986 and 1990. Here
we report its mid and long term effects on continence. The problems we have
encountered in these patients are discussed.
PMID- 9765772
TI - [Suburethral sling urethropexy: a vaginal approach].
AB - Considering the poor long term results with the bladder neck suspensions, the
poor results with the retropubic approach in obese or intrinsic sphincter
deficiency and the complexity of the classical retropubic sling procedure, a
simple vaginal sling urethropexy approach was developed. The vaginal mucosa is
opened at 12 o'clock under the urethra. Dissection of the endopelvic fascia is
undertaken. Polypropylene sutures are placed at the 4 corners of a free 2 x 4 cm
rectus abdominis muscle flap which is suspended under the bladder neck
transvaginally. Polypropylene sutures are tied at the rectus muscle through a 3
cm suprapubic incision. 25 patients were operated by one single surgeon. 7 had
previous uretropexies. Previous hysterectomies: 8. Average age: 57. Average
weight: 67.6. Severe stress incontinence was demonstrated in 23 patients. 9
patients had mixed incontinence. Average protective pads per day pre-op: 4.1. OR
time: 93.8 min. Blood loss was minimal. 10 patients had transient post op
retention (24 days average). 1 bladder perforation. 2 incisional hernias. 6
suprapubic wound infections. Average hospital stay: 5.95 days. The average follow
up was 22 months. All patients were either cured (76%) or improved. 73% were
satisfied (questionnaire). Despite a longer OR time, and the incidence of
transient post op retention, this vaginal sling urethropexy approach is a simple
and efficient procedure. It can be useful in previously operated or obese
patients. It is easier to perform than the more conventional retropubic or
combined (retropubic and vaginal) sling urethropexy.
PMID- 9765773
TI - [Attempted classification of scrotal contusions].
AB - We present a review of the literature and results of a survey involving 50 closed
scrotal traumas. Based on this analysis, we propose an anatomoclinical
classification of scrotal contusions based on what we consider to be the most
appropriate therapeutic management.
PMID- 9765774
TI - [The renal arterial pedicle in the human fetus].
AB - To analyze the incidence of renal arteries variations during the fetal period and
compare these findings with previous findings in adults, we studied the renal
arterial pedicle in 70 human fetuses ranging in age from 13 to 36 weeks
postconception. The fetuses were injected through the right common carotid artery
with a red polyester resin to fill in the arterial tree enabling the
identification and dissection of the small fetal arteries. The renal arteries
were analyzed considering their number, origin, direction and site of
penetration. Among the 70 fetuses studied, 30 (42.8%) presented at least one
kidney with renal artery variations. In 6 fetuses the variation was bilateral.
Among the total of 140 renal pedicles studied, 36 presented arterial variations
(25.7%). We did not find statistically significant difference between right and
left kidneys and between male and female fetuses. In the present study we did
find kidneys with more than 2 arteries, probably because we did not study kidneys
with any kind of development anomaly. Even kidneys with malrotations of the
vertical axis were removed from the study.
PMID- 9765775
TI - [Diagnosis of bladder neck obstruction in women].
AB - Bladder outlet obstruction in women is a rare entity, and difficult to diagnose.
In our series most of the patients had previous history of gyneco-obstetric or
urological procedures. Cystometry enabled us to diagnose the coexistence of
bladder instability and obstruction in 48% of the patients. We did not find
statistically significant differences between the patients with and without BI in
terms of degree of obstruction measured by uroflowmetry and pressure/flow
studies. Pressure/flow studies and Uroflowmetry had been the essential key in the
diagnosis of obstruction in our series. Cysto-urethrography and urethroscopy were
normal in over 50% of patients. The urethral calibration was abnormal in 16% of
the cases.
PMID- 9765776
TI - [Gangrene of the external genital organs. Apropos of 55 cases].
AB - Gangrene of the male external genitalia (GMEG) is characterized by necrotizing
cell evolving toward necrotizing of the soft tissues of the male genitalia and
possibly death. The cause may be primary infection called Fournier's gangrene
(5%) or secondary infection (95%) due to general or local factors. GMEG is a real
urinary emergency because of its local and general complications which lead to
death in 20% of cases. Precocious and massive antibiotherapy, a surgery to
unbridle and possibly reanimation, oxygenotherapy, urinary diversion or
colostomy, are required. We have treated 55 men with this affection from january
1988 to may 1996. Mean age was 58 years (range 20 to 85). The prodromial period
was about 12 days. Toxi-infectious shock was noted in 8 patients (14%). Six
patients (10%) developed renal acute insufficiency. Lesions were localized to the
male external genitalia in 24 cases and stretched to the inguinalis, to the
abdomen or to the thorax in 34 patients. The cause was a stricture of urethra in
23 cases (41%) diabetes in 18 cases (32%), anal abscess in 7 cases (13%). No
etiology was found in 6 cases (10%). Emergency treatment involved three
antibiotics, surgery to unbridle necrotizing tissue in all patients, reanimation
in 20 patients (35%), oxygenotherapy in 4 patients (7%), colostomy in 2 cases and
urinary drainage in 23 patients (42%). Free skins grafts were necessary in 6
patients (10%), 5 patients (9%) died due to septic shock. On the basis of these
observations and a review of the literature, we analyzed the ethiopathogenic,
bacteriological and therapeutic aspects of this affection marked by high
mortality in spite of therapeutic progress.
PMID- 9765777
TI - [Fournier's gangrene. Analysis of 32 cases].
AB - A series of 32 treated cases of Fournier's gangrene is analysed. All patients
were male, their age ranged from 19 to 89 years. In 16 cases (50%) the aetiology
of gangrene was urethral (37.5%), anorectal (12.5%) and in the 16 remaining cases
(50%) there was no identifiable cause. Mortality was high (28%) despite broad
spectrum antibiotics and aggressive surgical debridement. This mortality was
essentially associated to advanced age, debilitated state, delay in diagnosis and
toxi infectious context. The average hospital stay was 26.5 days.
PMID- 9765778
TI - [Urinary calculi and indinavir sulfate in patients with HIV infection. Apropos of
4 cases].
AB - We report on 4 cases of urinary stone observed in patients treated with the drug
Crixivan (Indinavir Sulfate) and review the literature. Comments include stone
composition, clinical aspects, treatment and prevention.
PMID- 9765779
TI - [Retroperitoneal liposarcoma. Apropos of 2 cases].
AB - We report two cases of retroperitoneal liposarcoma that required multiple
surgical excisions for locoregional relapse diagnosed by surveillance based on CT
scan. One patient has had adjuvant radiotherapy. With the literature review, we
discuss the pathologic and therapeutic aspects of these lesions.
PMID- 9765780
TI - [Cysts of the prostate. Apropos of 2 cases].
AB - Two prostatic cysts have been diagnosed by us since 1993. The first patient
presented with dysurial the second cyst was discovered incidentally. Transrectal
ultrasound examination was useful for diagnosis. Treatment was a puncture-
aspiration of the cyst in the first case, and abstention in the second one. A
review, of the epidemiological, pathological and therapeutic aspects of the
prostatic cysts is presented.
PMID- 9765781
TI - [Acute urine retention. Another presentation of a hydatid cyst of the kidney].
AB - We report on a case of hydatic cyst of the kidney, in a 12 year-old male,
revealed by an acute urinary retention. After a brief report of the common signs
of this parasitic disease, we emphasize the importance of hydaturia and acute
urinary retention as another revealing sign of this disease.
PMID- 9765782
TI - [A case of unrecognized bladder pheochromocytoma].
AB - Pheochromocytoma rarely occurs in the bladder. We report a fortuitously observed
case and review the main clinical, biological and radiological features.
PMID- 9765783
TI - [Urethral polyps in children: an unusual cause of obstruction of the lower
urinary tract].
AB - We report an unusual case of urethra polyp in a young child which caused
obstruction of the lower urinary tract. Endoscopy was successful.
PMID- 9765784
TI - [Bilateral testicular metastasis of cancer of the prostate].
AB - Testicular metastasis of prostate cancer rarely occurs. Bilateral localization is
exceptional. We report a new case of prostate adenocarcinoma with bilateral
testicular metastasis. The diagnosis was made on clinical and ultrasonic
arguments, and confirmed on the pathological specimen. Treatment consisted in a
bilateral orchidectomy, associated with nonsteroid androgens.
PMID- 9765785
TI - [Spermatocytic seminoma. Apropos of a case and review of the literature].
AB - We report a case of sperm cell seminoma caused by trauma. The data in the
literature indicate the frequency is less than 5% of all seminomas. This case was
exclusively located in the gonads and was a pure form. Orchidectomy with high
ligature of the cord and adjuvant radiotherapy at the dose of 25 Gy centered on
the para-aortic and subdiaphragmatic chains is adequate treatment. When
inguinoscrotal surgery is performed, this zone must be irradiated with 25 Gy.
Prognosis is satisfactory: 5-year survival is 100% with this protocol.
PMID- 9765786
TI - [Urachal remnants: excision or surveillance? Apropos of 3 cases and review of the
literature].
AB - Three cases of symptomatic umbilical residues revealed by hematuria and/or
mictional disorders are reported. Ultrasonography, computed tomography and
magnetic resonance imaging visualized an aspecific formation of the bladder dome.
Total exeresis requiring partial cystectomy in all cases was curative (tow years
follow-up). All clinical signs have disappeared.
PMID- 9765787
TI - [Nephrectomy for cancer in pregnant women. Apropos of a case].
AB - We report on the case of a young pregnant woman who had a malignant tumor of the
kidney. The pregnancy did not change the gold standard therapy: radical
nephrectomy. Because of the pregnancy the preoperative staging consisted of an
abdominal ultrasound and a magnetic resonance imaging for the local extension,
and of a chest X-ray looking for pulmonary metastases. According to the
literature pregnancy, a situation of immune depression, does not increase the
prevalence of malignant neoplasms.
PMID- 9765788
TI - [Treatment of hemangioma of the glans penis using Nd:Yag laser. Apropos of a
case].
AB - Hemangioma of urinary tract are unusual, being about 2% of all hemangiomas. We
present a case of a glans penis hemangioma. There is controversy concerning their
treatment and outcome. Our patient was treated with a Neodymium: Yag laser
irradiation, with complete morphological recuperation.
PMID- 9765789
TI - [Drug-resistant genito-urinary rhabdomyosarcoma in children with primary psoas
abscess. Apropos of a case].
AB - We report an unusually uncommon case of genitourinary rhabdomyosarcoma in a child
which was chemoresistant and complicated by a primary psoas abscess which
presented as a pelvic mass associated with an abscess of the right iliac fossa.
Ultrasound and CT investigations suggested the diagnosis of a centropelvic tumor
which was confirmed at puncture-aspiration. MRI was most contributive giving a
precise description of the local extension. Intensive multi-drug chemotherapy
would appear to have improved outcome in patients with poor-prognosis Maurer
group III tumors. In exceptional cases when no tumor response is obtained,
carcinological surgery with large dissection, possibly with adjuvant
radiotherapy, is indicated. Percutaneous drainage of the deep psoas abscess is as
effective as classical surgery and spares the abdominal wall, particularly
important if a second operation should be needed. Multidisciplinary management is
required for the treatment of this highly malignant tumor.
PMID- 9765790
TI - Carnosine: its properties, functions and potential therapeutic applications.
AB - Carnosine and related dipeptides such as anserine are naturally-occurring
histidine-containing compounds. They are found in several tissues most notably in
muscle where they represent an appreciable fraction of the total water-soluble
nitrogen-containing compounds. The biological role of these dipeptides are
conjectural but they are believed to act as cytosolic buffering agents. Numerous
studies have demonstrated, both at the tissue and organelle level, that they
possess strong and specific antioxidant properties. Carnosine and related
dipeptides have been shown to prevent peroxidation of model membrane systems
leading to the suggestion that they represent water-soluble counterparts to lipid
soluble antioxidants such as alpha-tocopherol in protecting cell membranes from
oxidative damage. Other roles ascribed to these dipeptides include actions as
neurotransmitters, modulation of enzymic activities and chelation of heavy
metals. Many claims have been made in respect of therapeutic actions of carnosine
and histidine-containing dipeptides. These include antihypertensive effects,
actions as immunomodulating agents, wound healing and antineoplastic effects.
Many of these claims have not been convincingly documented nor subject to
rigorous clinical evaluation. Nevertheless, there are examples where studies have
shown considerable promise. One is the treatment of senile cataract in dogs and
another is in acceleration of healing of surface wounds and burns to the skin. It
is clear from this review that many of the effects of these histidine-containing
dipeptides, especially in regard to claims for their therapeutic effects, need to
be subjected to critical experimental and clinical examination. Several
applications do, however, show clear evidence of being useful therapeutic agents.
PMID- 9765791
TI - In vivo mutational analysis of bacteriophage Mu operators.
AB - In bacteria lysogenic for bacteriophage Mu, the phage repressor binds to a
tripartite operator region, O1,O2,O3, to repress the lytic promoter pE, located
in O2, and negatively autoregulate its own synthesis at the pCM promoter located
in O3. We isolated and characterized operator mutations which lead to
derepression of pE. Their location in the first and third repressor-consensus
binding sequences in O2 confirms the importance of these sites for
repressor/operator interactions.
PMID- 9765792
TI - Long-term in vitro cultivation of Borrelia burgdorferi sensu lato strains:
influence on plasmid patterns, genome stability and expression of proteins.
AB - Low (7th) and high (298th/304th) in vitro passages (cultivated over a period of 3
years) of two human Borrelia burgdorferi sensu lato strains, PKo (B. afzelii) and
PBi (B. garinii) were compared by pulse-field gel electrophoresis, Southern blot,
sequencing of the ospA gene, SDS-PAGE and Western blot. Digestion of genomic DNA
with ApaI, BssHII, KspI, MluI, SmaI and XhoI did not reveal any differences
between low and high passages. The loss of two linear plasmids with sizes of 6
and 31 kbp was detected in strain PKo between passages 34-50 and 101-304,
respectively, whereas the ospA-carrying plasmid remained unchanged. In contrast,
analysis of linear plasmid profiles obtained from low and high passages of B.
garinii strain PBi showed no differences. Sequence analysis of the ospA gene
demonstrated no difference in the strain PBi and one nucleotide exchange in the
strain PKo when low and high passages were compared. The observed transition (G
A) in the third codon position did not alter the amino acid sequence. However,
the rate of expression of the outer surface proteins OspA, OspB and OspC of
strain PKo during low and high stages of cultivation varied significantly. In
summary, our data suggest that the B. burgdorferi sensu lato genome is stable
during long-term in vitro cultivation.
PMID- 9765793
TI - The adc locus, which affects competence for genetic transformation in
Streptococcus pneumoniae, encodes an ABC transporter with a putative lipoprotein
homologous to a family of streptococcal adhesins.
AB - To identify new components involved in the phenomenon of transformation in
Streptococcus pneumoniae, a library of potential mutants has been generated by
random insertion of an erythromycin resistance gene. Transformation-deficient
mutants were screened using an in situ colony transformation test. The adc locus,
which was identified in this search, was cloned and sequenced. Sequence analysis
revealed a putative operon of three ORFs (adcC, adcB and adcA) with homology to
ATP-binding cassette (ABC) transport operons encoding streptococcal adhesins such
as ScaA of S. gordonii and FimA of S. parasanguis. adcA can encode a lipoprotein
of 313 amino acid residues containing a putative metal-binding site. The
polypeptide shows about 30% sequence identity with ScaA and FimA. We discuss
evidence which leads us to propose that AdcA, together with a set of 14 proteins
including ScaA, FimA and homologous adhesins, defines a new family of external
solute-binding proteins, cluster 9, specific for metals.
PMID- 9765795
TI - Response of Brucella suis 1330 and B. canis RM6/66 to growth at acid pH and
induction of an adaptive acid tolerance response.
AB - Acid pH is an environmental stress often encountered by Brucella during both the
"environmental" and the "pathogenic" stages of its life. We have investigated the
behaviour of B. suis biovar 1 and B. canis in acid conditions. Growth at
suboptimal pH was characterized by a dramatic reduction in growth yield due to an
early onset of stationary phase. B. suis was more resistant to low pH than B.
canis, which lysed at pH 4.6. Viable counts measured after a 4-h acid shock at pH
3.2 showed that the relative survival of B. suis was 1,000-fold greater than that
of B. canis. An adaptive acid tolerance response (ATR) was induced in both
species by culture at pH 5.8; however, while the acid-sensitive B. canis had more
than a 2,000-fold increase in survival following acid shock at pH 3.2, the
increase in survival of B. suis was only around 50-fold. The kinetics of the
induction of ATR were followed: for B. suis, 1-2 h (1 generation) at pH 5.8 were
required to induce acid tolerance (50-fold protection), and these levels remained
constant over 24 h. B. canis became relatively acid-resistant after only 30-min
exposure to pH 5.8. Levels of acid tolerance continued to increase and were
maximal at 24 h. Stationary phase pH 7.2 cultures of either species did not
exhibit acid resistance, suggesting that, like Salmonella, Brucella does not have
an rpoS-controlled stationary phase acid resistance.
PMID- 9765794
TI - Molecular characterization of a 17-kDa outer-membrane protein from Klebsiella
pneumoniae.
AB - A cosmid-based genomic library of Klebsiella pneumoniae 52145 (O1:K2) was
introduced into Escherichia coli, and clones were screened for the bacteriocin
28b resistance phenotype. One clone was found which conferred partial resistance
to bacteriocin 28b. By using Tn5tac1 insertions, it was shown that this phenotype
was due to the expression, in E. coli, of an outer-membrane protein (OMP) with an
apparent molecular mass of 17 kDa (OmpK17). The DNA region defined by insertion
mutagenesis was sequenced and found to contain an ORF of 510 bp. The deduced
amino acid sequence has 170 residues with a theoretical molecular mass of 18.4
kDa. The protein contains an N-terminal signal sequence of 24 amino acid
residues. When compared with other enterobacterial OMPs, OmpK17 most closely
resembles members of a family of small OMPs of Enterobacteriaceae the known
functions of which appear to be related to virulence. Immunoblotting experiments
showed that OmpK17 is also present in various K. pneumoniae strains belonging to
different O and K serotypes.
PMID- 9765796
TI - Isolation of a soil psychrotrophic toluene-degrading Pseudomonas strain:
influence of temperature on the growth characteristics on different substrates.
AB - Two psychrotrophic toluene-degrading Pseudomonas putida strains were isolated at
low temperature from a toluene-polluted soil, thereby demonstrating that toluene
degradation at low temperature occurred in nature, a finding of possible interest
for soil bioremediation procedures. In one of these strains, two aromatic
compounds (toluene and benzoate) were degraded, most likely through different
pathways. To study the effect of the growth temperature on the metabolism of
these substrates, we studied the evolution of the maximal growth rates with
respect to both temperature and substrate. It was shown that not only cardinal
temperatures but also temperature characteristics deduced from the Arrhenius plot
of maximal growth rates differed when the different substrates were used as sole
carbon and energy source.
PMID- 9765797
TI - Effect of natural amphipathic peptides on viability, membrane potential, cell
shape and motility of mollicutes.
AB - The antibiotic activity of ten amphipathic peptides was investigated in six
species of mollicutes belonging to the genera Acholeplasma, Mycoplasma and
Spiroplasma. A. laidlawii was the most sensitive and M. mycoides subsp. mycoides
SC the most resistant. Animal defence peptides (cecropins A and P1, and magainin
2) proved to be less potent than bee-venom mellitin and most of the peptides
produced by bacteria (globomycin, gramicidin S, surfactin and valinomycin) or
fungi (alamethicin). Gramicidin S was by far the most active peptide, with
minimal inhibitory concentrations ranging from 2 to 50 nM. Alamethicin,
gramicidin S, mellitin and surfactin had a cidal effect, whilst cecropins,
globomycin, magainin 2, polymyxin B and valinomycin proved to be static. The
peptides altered the membrane potential of spiroplasma cells with a potency
independent of their linear or cyclic structure. However, globomycin depolarized
the plasma membrane only weakly, whilst polymyxin B, in order to be active,
required prior hyperpolarization of the membrane. The peptides also induced the
loss of cell motility and helicity in spiroplasmas, suggesting that motility and
cell shape in these bacteria are coupled to the transmembrane electrochemical
gradient. Globomycin, an inhibitor of signal-peptidase II, prevented the growth
of spiroplasmas, M. gallisepticum, and M. genitalium, but not that of A.
laidlawii and M. mycoides subsp. mycoides SC, although the latter also
synthesized membrane lipoproteins. Inhibition of spiralin processing by
globomycin was demonstrated in S. citri and S. melliferum, with a more pronounced
effect in the second species.
PMID- 9765798
TI - Detection of the Escherichia coli attaching and effacing gene (eaeA) in
enteropathogenic strains by polymerase chain reaction.
PMID- 9765799
TI - A cheA cheW operon in Borrelia burgdorferi, the agent of Lyme disease.
AB - Borrelia burgdorferi sensu stricto homologues of cheA and cheW were cloned and
characterized. A combination of strategies such as polymerase chain reaction
(PCR) using degenerate primers, random-primed gene walking PCR and construction
of a lamda library were used to identify the putative cheA gene. Sequence
analysis of the DNA fragments obtained from the CT strain identified a 2,592-bp
open reading frame (ORF) encoding an 864-amino-acid protein with significant
similarity (53-64.6% identical residues) to the CheA of several genera of
eubacteria. In particular, hallmarks of a histidine kinase family were found such
as the location of the histidine autophosphorylation domain very close to the NH2
terminus and the nucleotide-binding site. A second ORF located immediately
downstream from the putative borrelial cheA gene encoded a 195-amino-acid protein
which displayed a high level of similarity to bacterial CheW. Using reverse
transcription PCR, we demonstrated that cheA and cheW form an operon with an
upstream, unidentified ORF. The cheA and cheW homologues were located at 722-737
kbp, 738-768 kbp and 743-824 kbp on the linear chromosomes of B. burgdorferi
sensu stricto, B. garinii and B. afzelii, respectively. Identification of cheA
and cheW is the first step toward elucidation of a possible role of chemotaxis in
virulence of the Lyme disease borreliae.
PMID- 9765800
TI - The partial sequence of the Plasmodium falciparum histone H4 gene.
PMID- 9765801
TI - Identification of different daughter and parent subpopulations in an
asynchronously growing Saccharomyces cerevisiae population.
AB - Under all growth conditions, a growing Saccharomyces cerevisiae yeast population
is extremely heterogeneous, since individual cells differ in their cell size;
this is due to their position in the cell division cycle and their genealogical
age. To gain insight into the structure of a growing yeast population, we used a
recently developed flow cytometric approach which enables, in asynchronously
growing S. cerevisiae populations, tagging of both the cell age and the protein
content of individual cells. This approach enabled the identification of daughter
cells belonging to different cell cycle positions (i.e. newborn, G1, S + G2 + M +
G1*, and dividing), thus yielding information about the relative fraction in the
whole population, cell size and variability. More limited information could be
obtained for the parent subpopulation; however, we were able to identify and
characterize the dividing parent cells. The coefficient of variation (CV) of the
protein content distribution for the dividing parents (27) was much higher than
the CV of dividing daughters (18). Further findings obtained indicated a large
overlap between the cell protein content distributions of daughter and parent
cells as well as between the protein content of cells of the same subpopulation
but belonging to different stages of the cell division cycle. The analysis of
these differences enables a better understanding of the complex structure of an
asynchronously growing yeast population.
PMID- 9765802
TI - Cloning and expression of colonization factor antigen I (CFA/I) epitopes of
enterotoxigenic Escherichia coli (ETEC) in Salmonella flagellin.
AB - Oligonucleotides coding for linear epitopes of the fimbrial colonization factor
antigen I (CFA/I) of enterotoxigenic Escherichia coli (ETEC) were cloned and
expressed in a deleted form of the Salmonella muenchen flagellin fliC (H1-d)
gene. Four synthetic oligonucleotide pairs coding for regions corresponding to
amino acids 1 to 15 (region I), amino acids 11 to 25 (region II), amino acids 32
to 45 (region III) and amino acids 88 to 102 (region IV) were synthesized and
cloned in the Salmonella flagellin-coding gene. All four hybrid flagellins were
exported to the bacterial surface where they produced flagella, but only three
constructs were fully motile. Sera recovered from mice immunized with
intraperitoneal injections of purified flagella containing region II (FlaII) or
region IV (FlaIV) showed high titres against dissociated solid-phase-bound CFA/I
subunits. Hybrid flagellins containing region I (FlaI) or region III (FlaIII)
elicited a weak immune response as measured in enzyme-linked immunosorbent assay
(ELISA) with dissociated CFA/I subunits. None of the sera prepared with purified
hybrid flagella were able to agglutinate or inhibit haemagglutination promoted by
CFA/I-positive strains. Moreover, inhibition ELISA tests indicated that antisera
directed against region I, II, III or IV cloned in flagellin were not able to
recognize surface-exposed regions on the intact CFA/I fimbriae.
PMID- 9765803
TI - Genome size variation among recent human isolates of Salmonella typhi.
AB - We performed genome size estimation of 17 recent human isolates of Salmonella
typhi from geographically diverse regions using pulsed-field gel electrophoresis
(PFGE) after digestion of chromosomal DNA with restriction endonucleases XbaI (5'
TCTAGA-3'), AvrII (5'-CCTAGG-3') and SpeI (5'-ACTAGT-3'), and summation of the
sizes of restriction fragments obtained. All 17 isolates had circular
chromosomes, and genome sizes differed by as much as 959 kb, ranging from 3,964
to 4,923 kb (mean genome size = 4,528 kb). The data obtained confirm the
usefulness of PFGE in studies of bacterial genome size and are in agreement with
recent results indicating considerable genetic diversity and genomic plasticity
of S. typhi. The variation in genome sizes noted may be relevant to the observed
biological properties of this important human pathogen, including its virulence.
PMID- 9765804
TI - Molecular characterization of an n-alkane-degrading bacterial community and
identification of a new species, Acinetobacter venetianus.
AB - Twenty-five bacterial strains isolated from the Venice lagoon and implicated in
the degradation of n-alkanes, n-alkanols, n-alkanals and n-alkanoates were
characterized in molecular and physiological terms. The isolates were grouped by
amplified ribosomal DNA restriction analysis (ARDRA) into seven clusters,
corresponding to seven species, six of which were identified on the basis of 16S
rDNA sequencing. Genetic variability among strains was shown by random amplified
polymorphic DNA (RAPD). Only strains of the new species Acinetobacter venetianus
grew with n-alkanes (C10, C14 and C20) and their respective oxidation products as
sole carbon sources. Strains of the other three species identified thrived on n
alkane oxidation products (n-alkanols, n-alkanals, n-alkanoates). The other three
species were not able to grow on any of the substrates tested. Analysis of
plasmid content showed that only A. venetianus strains harboured plasmids. These
plasmids contained sequences homologous to the Pseudomonas oleovorans alkBFGH
genes.
PMID- 9765805
TI - Emergence of Cu(++)-tolerant mutants defective in gellan synthesis in Cu(++)
stressed cultures of Sphingomonas paucimobilis.
AB - Cells defective in gellan synthesis appeared during cultivation of the gellan gum
producing strain Sphingomonas paucimobilis R40 with inhibitory concentrations of
copper, supplied as CuCl2. The percentage of less mucoid colonial variants
dramatically increased with the increase in Cu++ supplementation, reaching 85% of
total viable cells at the maximal concentration for growth. Results reported in
this work indicate that emergence of colonial variants defective in gellan
synthesis results from Cu(++)-induced mutation and the growth advantage of these
mutants in Cu(++)-stressed cultures. In fact, DNA homologous recombination
strongly increased with the increase in copper supplementation as indicated by
the regeneration of kanamycin-resistant cells of R40 harbouring plasmid pBX404-7,
which carries two non-overlapping truncated genes derived from a gene conferring
kanamycin resistance. The four major groups of colonial mutants that emerged from
Cu(++)-stressed cultures of R40 exhibited reduced growth rate and biomass yield
in the absence of Cu++ stress and produced decreased levels of exopolysac-charide
(EPS) which yielded solutions of lower or negligible viscosity. The level of
increased Cu++ tolerance of these mutants, assessed by the inhibitory effect of
Cu++ on growth, correlated with the degree of loss of the ability to secrete high
molecular-mass EPS. Consistent with the growth advantage of gellan-defective
mutants in Cu(++)-stressed cultures, the non-producing strain RP10, spontaneously
obtained during extended cultivation of R40, also exhibited a higher tolerance to
Cu++. In addition, its non-mucoid phenotype was stably maintained during Cu(++)
stressed cultivation despite the stimulation of homologous recombination by Cu++.
PMID- 9765806
TI - Glycoside hydrolase production by an anaerobic rumen fungus Caecomyces communis.
AB - The ruminal fungus Caecomyces communis was grown anaerobically either in a
discontinuous cultivation system or in a fermentor with daily withdrawal and
addition of fresh medium. Lowe and Orpin media were tested. The best culture
conditions for glycoside hydrolase production were obtained in Lowe medium with
daily fresh medium addition, whereas the Orpin medium with ruminal fluid was
favourable to fungal growth and to the enzyme export process. Among glycoside
hydrolases assessed in both culture fluid and cellular homogenate, beta-D
fucosidase activity was preponderant. Most studied enzymes were mainly associated
with cells (from 50% to 99%). Glycoside hydrolase activities were constitutive,
but their level was regulated by a carbon source. beta-D-fucosidase and beta-D
xylosidase activity production was activated by the association of glucose plus
cellobiose, whereas beta-D-glucosidase activity production was stimulated by
cellobiose alone. Enzyme release could be favoured by glucose alone or by Ray
grass hay added to glucose plus cellobiose.
PMID- 9765807
TI - Increase in beta-galactosidase activity in a non-isothermal bioreactor utilizing
immobilized cells of Kluyveromyces fragilis: fundamentals and applications.
AB - The beta-galactosidase activity of Kluyveromyces fragilis cells immobilized in a
kappa carrageenan gel was studied in a bioreactor functioning under isothermal
and non-isothermal conditions. We observed an increase in enzyme activity which
was found to be proportional to the intensity of the temperature gradient applied
across the biocatalytic membrane, as well as to the average temperature of the
bioreactor. The efficiency of such a non-isothermal bioreactor was calculated
with respect to the yield of a bioreactor working under comparable isothermal
conditions and was evaluated in terms of reduction of processing times in
industrial applications. The possibility that enzyme activity in living cells is
affected by non-isothermal conditions naturally existing owing to metabolic heat
production is also discussed.
PMID- 9765808
TI - RegF, an SspA homologue, regulates the expression of the Neisseria gonorrhoeae
pilE gene.
AB - The Neisseria gonorrhoeae pilE gene codes for a type IV pilin, the major subunit
of pili which constitute an essential virulence factor during gonococcal
infection. Expression of pilE seems to be highly regulated, which may allow
piliation to adapt to growth conditions. From an N. gonorrhoeae genomic library,
we selected plasmid pNG200 encoding a protein (RegF) which caused a 5-fold
increase in the expression of pilE::cat fusion in Escherichia coli. This
regulation was mediated via the complex pilE promoter region, comprising
potential sigma 70- and sigma 54-dependent promoters, and could not be observed
in the absence of an active sigma 54 factor. The RegF protein (23,149 Da) showed
42% identity with the E. coli "stringent starvation protein", SspA. This protein
was shown to interact with the RNA polymerase holoenzyme and to play a role in
the expression of at least 11 proteins in E. coli. In an N. gonorrhoeae strain
carrying a regF::mTn3Cm3 mutation constructed by allelic exchange, it was
observed that pilin expression was enhanced. Our results were consistent with a
model in which (i) in N. gonorrhoeae, RegF acts as a negative regulator of pilE
transcription, and (ii) in E. coli, RegF increases pilE transcription by
preventing sigma 54-associated steric hindrance at pilE promoters described
previously.
PMID- 9765809
TI - Effect of saline concentration, pH and growth temperature on the invasive
capacity of Listeria monocytogenes.
AB - The invasive ability of Listeria monocytogenes was monitored after treatment at
different pH, temperature and salt concentrations. We found a complete loss of
invasive ability in bacteria grown at pH < or = 4.5 independently of the
incubation temperature (4, 22 and 30 degrees C). Increasing salt concentrations
at 22 and 30 degrees C had no effect at pH 7, while drastically affecting
invasive ability at pH 5. The expression of two proteins of 30 and 88 kDa,
extracted from the culture supernatant and the cell wall, respectively, was
detected only in cells grown under normal conditions, but not after low pH and
high salt concentration treatment.
PMID- 9765810
TI - Strategy for the detection of Helicobacter species by amplification of 16S rRNA
genes and identification of H. felis in a human gastric biopsy.
AB - The aim of the present work was to develop polymerase chain reactions (PCRs)
based on the conserved nucleotide sequence of the 16S rRNA gene for detection of
bacteria of the Helicobacter genus in human antral biopsy samples. The assay for
Helicobacter spp was developed by amplifying a 399-bp 16S rRNA gene sequence
specific to the genus Helicobacter. The identity of the amplicon was confirmed by
hybridization with an internal probe and by restriction by endonuclease VspI
showing two expected fragments of 295 and 104 base pairs. A total of 65 dyspeptic
patients from France and New Caledonia were screened for Helicobacter spp
infection through the use of the following diagnostic assays on biopsy specimens
collected through endoscopy: direct detection of bacteria in histological
sections by Giemsa and Warthin Starry staining, urease test and bacterial
isolation, PCR for Helicobacter pylori ureC/glmM gene, and PCR targeted to 16S
rRNA genes. The 16S rRNA gene PCR assay was able to detect down to 680 bacterial
cells, as assessed by agarose gel electrophoresis, and down to 4 bacterial cells
by hybridization of amplicon with the internal probe. The 16S rRNA PCR test was
100% specific and sensitive; results obtained with this test were in agreement
with the visualization of bacteria by histology. Urease test and culture were
86.4% and 22.7% sensitive, and 96.5 and 100% specific, respectively. The H.
pylori ureC/glmM gene-based PCR was 100% specific and only 95.4% sensitive, since
one biopsy from a Melanesian patient contained a Helicobacter strain other than
H. pylori. For this Melanesian patient, a branch-specific PCR targeting the
epsilon branch of Proteobacteria was used to amplify a 967-bp amplicon. This
amplicon was sequenced and matched with the H. felis sequence. This was confirmed
using an H. felis-specific urease PCR test.
PMID- 9765811
TI - Characterization of avian Chlamydia psittaci strains using omp1 restriction
mapping and serovar-specific monoclonal antibodies.
AB - In the present study, 60 avian Chlamydia psittaci isolates were characterized
using restriction fragment length polymorphism as well as serovar-specific
monoclonal antibodies, enabling a comparison between the two characterization
methods. Sixty avian C. psittaci isolates were characterized by Alul restriction
mapping of the major outer membrane protein gene omp1 obtained after
amplification by the polymerase chain reaction. The 60 avian C. psittaci strains
were also characterized using serovar-specific monoclonal antibodies in a
microimmunofluorescence test. Digestion of 60 avian C. psittaci omp1 amplicons by
Alul generated 5 of the 6 known distinct restriction patterns (A, B, D, E and F).
Restriction pattern C was not observed. Serotyping revealed 4 avian C. psittaci
serovars (A, B, C and D). None of the 60 isolates was typed as serovar E. AluI
restriction patterns A, B, D and E corresponded in 98% of the cases to serovars
A, B, C and D, respectively. One isolate, classified as serovar A, generated
restriction pattern F instead of A. Genotyping enabled a more precise
differentiation of avian C. psittaci serovar A strains. Serovar A strains were
divided into two groups according to their Alul restriction pattern (A or F). For
epidemiological studies, genotyping can thus be a highly valuable alternative to
serotyping, especially when applied directly to the clinical samples.
PMID- 9765812
TI - Overexpression, purification and characterization of Dictyostelium calcineurin A.
AB - The catalytic subunit of Ca2+/calmodulin-dependent protein phosphatase
(calcineurin A) was overexpressed about 50-fold in Dictyostelium discoideum cells
transformed with a vector containing the cDNA for D. discoideum calcineurin A
under control of the actin-6 promoter. In crude lysates from the overexpressing
cell line, high Ca2+/calmodulin-stimulated phosphatase activity was detected.
Calcineurin A was purified by anion exchange chromatography and calmodulin
Sepharose affinity chromatography, and the enzymatic activity of the isolated
protein was characterized. Its phosphatase activity was strictly dependent on the
addition of divalent metal ions such as Mg2+ or Mn2+. Disulphide-reducing agents
increased the activity more than 10-fold. Ca2+/calmodulin stimulated the activity
by a factor of 2.5-5. Despite the high extra Ca2+/calmodulin-dependent
phosphatase activity, the overexpressing cell line showed no phenotypic
aberrations.
PMID- 9765813
TI - Prochlorothrix hollandica PCC 9006: genomic properties of an axenic
representative of the chlorophyll a/b-containing oxyphotobacteria.
AB - Prochlorothrix hollandica is an oxygenic photosynthetic prokaryote that differs
from the cyanobacteria in having chlorophyll a/b-protein complexes instead of
phycobilisomes as major light-harvesting antennae. We report the isolation and
culturing of an axenic strain of P. hollandica, available from the Pasteur
Culture Collection of Cyanobacteria as strain PCC 9006. The strain has a mean DNA
base composition of 51.6 +/- 0.1 mol% G+C and a genomic complexity of 3.37 +/-
0.17 x 10(9) daltons (5,505 kb). A reiterated DNA sequence represents
approximately 4.4% of the genome. Restriction enzyme isoschizomers with different
sensitivities to base methylation were used to demonstrate that most A residues
in the sequence GATC are methylated in P. hollandica DNA and that this
methylation increases with culture age. Furthermore, some C residues are
methylated, although the specificity of the C methylation system does not match
that of well-characterized C methylases. Nucleotide analysis showed that up to
approximately 3.5% of both dA and dC residues are methylated in P. hollandica
DNA.
PMID- 9765814
TI - Production of substituted naphthalene dihydrodiols by engineered Escherichia coli
containing the cloned naphthalene 1,2-dioxygenase gene from Pseudomonas
fluorescens N3.
AB - Naphthalene dioxygenase, a key enzyme in the dihydroxylation of naphthalene, is
encoded by the plasmid pN3, responsible for naphthalene metabolism in Pseudomonas
fluorescens N3. The naphthalene dioxygenase, including all the sequences for its
expression and the regulatory region, has been localized on the 4.3-kb HindIII
ClaI fragment and on the 3.5-kb HindIII fragment of the plasmid pN3, by Southern
analysis using as probes nahA and nahR genes, the homologous genes of the plasmid
NAH7 from Pseudomonas putida G7. We cloned in Escherichia coli JM109 the
dioxygenase gene and its regulatory region and developed an efficient bacterial
system inducible by salicylic acid, able to produce dihydrodiols. E. coli
containing recombinant plasmids carrying the dioxygenase gene were analysed for
their potential as a biocatalytic tool to produce dihydrodiols from different
naphthalenes with the substituent on the aromatic ring at the alpha or beta
position. The dihydrodiols, identified by HPLC (high-performance liquid
chromatography) and 1H-NMR (nuclear magnetic resonance) were produced with yields
ranging from 50 to 94%. The degree of bioconversion efficiency depends on the
nature and the position of the substituent and indicates the broad substrate
specificity of this dioxygenase and its potential for the production of a wide
variety of fine chemicals.
PMID- 9765815
TI - Biodegradation of phenols by a eukaryotic alga.
PMID- 9765816
TI - Further genetic analysis of the C-terminal external loop region in Escherichia
coli maltoporin.
AB - LamB specifically facilitates the diffusion of maltose and maltodextrins through
the bacterial outer membrane, and acts as a general (i.e. non-specific) porin for
small hydrophilic molecules (< 600 daltons). We reported previously that deletion
of the last predicted external domain near the C-terminus of the Eschirichia coli
LamB protein (residues 376 to 405), affected in vivo the binding and transport of
maltodextrins (specific pore functions), and also increased bacterial sensitivity
to large antibiotics. The residues covered by this deletion correspond almost
exactly to the major cell surface loop of LamB on the structural model based on X
ray crystallography (loop L9, residues 375 to 405). The L9 loop comprises a large
central portion, which varies in size and sequence between the LamB proteins from
different species. This variable region is flanked by two highly charged and
conserved portions, which overlap with the adjacent beta strands. To identify
subregions in L9 that influence the pore properties of LamB, we constructed and
analysed nine mutants in loop L9 and its flanking sequences. Deletion of the 23
amino-acids central variable portion of the loop (residues 379 to 401), and
deletion of the downstream conserved region (residues 402 to 409), only
moderately affected specific maltoporin function. In contrast, deletion of the
conserved region (residues 372 to 378) upstream of the variable portion strongly
decreased specific maltoporin function and also increased sensitivity to large
antibiotics, accounting for most, if not all, of the effects of the complete
deletion of L9.
PMID- 9765817
TI - Activity of protein MalE (maltose-binding protein) fused to cytoplasmic and
periplasmic regions of an Escherichia coli inner membrane protein.
AB - We analysed the properties of mature MBP (maltose-binding protein or MalE
protein) fused to an integral cytoplasmic membrane protein of Escherichia coli.
Fusion of MalE to the first MalG periplasmic loop enabled a strain defective in
the malE gene to utilize maltose. In contrast, fusion of MalE to a cytoplasmic
loop did not complement the malE delta 444 deletion. We obtained results highly
correlated with those obtained by using alkaline phosphatase as a reporter for
the topology of MalG. We discuss the possibility of genetically determining the
topology of cytoplasmic membrane proteins by a method based on engineered fusions
to MBP.
PMID- 9765818
TI - The recA gene from Streptomyces rimosus R6: sequence and expression in
Escherichia coli.
AB - The recA gene from Streptomyces rimusus encodes a 376-amino acids polypeptide
(M(r) 39,702) that is one of the largest bacterial RecA proteins observed.
Detailed analyses of the Streptomyces RecA proteins showed that all possess an
additional and unique C-terminal, rich in lysines and alanines, which can form an
additional terminal alpha helix. Expression of the S. rimosus RecA protein in
Escherichia coli FR333 (delta recA306) was demonstrated using antibodies raised
against E. coli RecA protein; expression was possible only from the S. rimosus
promoter. A Streptomyces-E. coli-like promoter sequence (TTGACA-18bp-TCTTAT) was
found in the A+ T-rich region 135-165 base pairs upstream from the initiation
codon and was related to Bacillus subtilis DNA damage-inducible promoters.
PMID- 9765819
TI - Distribution of surface-exposed antigenic glycolipids in recent clinical isolates
of Mycobacterium tuberculosis.
AB - The distribution of surface-exposed antigenic glycolipids in seven recent
clinical isolates of Mycobacterium tuberculosis was established. Thin-layer and
liquid chromatographies revealed a uniformity in the glycolipid pattern. Chemical
analysis of the individual glycolipids of a selected strain enabled the
identification of glycolipids of serological interest in all the other clinical
isolates. Phenolic glycolipid-Tb1 (PGL-Tb1) was lacking in all strains, but
appreciable amounts of a partially deglycosylated version (PGL-Tb1D) were present
in the seven isolates. Diacyltrehaloses (DATs) were detected in all strains,
showing themselves to be major glycolipids. Lipooligosaccharides (LOS-II) were
present in the seven strains studied though only in trace amounts. These results
shed new light on the open debate on the distribution of these interesting
glycolipids in typical clinical isolates of M. tuberculosis. In the search for a
serological test for tuberculosis, and in accordance with our observations, we
believe that PGL-Tb1 and LOS-II should not be the target molecules for serology
and that it is worthwhile to continue investigating the value of DATs as
antigens. We also believe that it would be of interest to undertake research to
assess the usefulness of PGL-Tb1D as an antigen.
PMID- 9765820
TI - Lipopolysaccharide biosynthesis genes in koala type I Chlamydia: cloning and
characterization.
AB - We showed in 1988 that there are two strains of Chlamydia psittaci which infect
the koala (Phascolarctos cinereus). In order to further investigate the role of
these chlamydial strains in pathogenesis, we have attempted to identify genes of
koala type I strain chlamydia which are involved in the immunogenic response.
Transformation of Escherichia coli with a plasmid containing a 6.3-kb fragment
(pKOC-10) of C. psittaci DNA caused the appearance of a specific chlamydial
lipopolysaccharide (LPS) epitope on the host strain. The smallest DNA fragment
capable of inducing the expression of chlamydial LPS was an XbaI fragment, 2.4 kb
in size (pKOC-5). DNA sequence analysis of the complete fragment revealed regions
of high identity, at the amino acid level, to the gseA genes of C. pneumoniae, C.
psittaci 6BC and C. trachomatis, and the kdtA gene of E. coli which code for
transferases catalysing the addition of 3-deoxy-D-manno-octulosonic acid (Kdo)
residues to lipid A. Two open reading frames (ORFs) of 1,314 and 501 nucleotides
in size, within the 2.4-kb fragment, were evident, and mRNA species corresponding
to these ORFs were detected by Northern analysis. Both ORF1 and ORF2 are required
for the appearance of chlamydia-specific LPS on the surface of recombinant E.
coli.
PMID- 9765822
TI - Heterogeneity of Lyme disease spirochaetes within individual vector ticks.
AB - To determine whether Lyme disease spirochaetes (Borrelia burgdorferi) within
vector ticks (lxodes dammini) sampled from enzootic sites comprise single or
mixed populations, we compared their reactivity to a polyclonal rabbit immune
serum with that to a battery of monoclonal antibodies (mAb) against OspA, OspB
and flagellin. More spirochaetes were recognized by the polyclonal antibody than
with the mAbs. Spirochaetes from field-sampled ticks reacted poorly to mAbs
against OspB. No such differences in reactivity to polyclonal or monoclonal
antibodies were observed for the N40 strain of B. burgdorferi from BSK cultures
and infected laboratory-reared vector ticks. We conclude that in nature each tick
may be infected by an antigenically heterogeneous mixture of spirochaetes.
PMID- 9765821
TI - An mpb-64 flanking sequence specific for Mycobacterium bovis.
AB - A clone carrying a plasmid with the mpb-64 gene and 3' flanking sequences
(plasmid pMBA122) was detected during the screening of a Mycobacterium bovis
genomic library with sera from infected cattle. When the pMBA122 insert was used
as a probe in Southern blots against PvuII-digested mycobacterial DNA, it
distinguished the different M. tuberculosis complex species. This probe
hybridized with a 7-kb band in M. tuberculosis, a 5-kb band in M. bovis and a 3
kb band in M. tuberculosis complex strains from wild seals. Smal genomic
digestions enabled us to locate this polymorphic region downstream of the mpb-64
gene. In order to clone this particular region, we designed a pair of PCR
primers. Unexpectedly, these primers amplified only M. bovis DNA; no
amplification was seen in M. tuberculosis DNA. When the annealing temperature was
lowered from 70 to 55 degrees C, an amplification product of the same size was
obtained with M. tuberculosis. This product was cloned and sequenced, and showed
partial homology to the M. bovis amplified fragment. Therefore, this region
comprises M. bovis sequences with a lower homology with M. tuberculosis than
other compared sequences. This suggests that a more precise differentiation
method at the species level for the M. tuberculosis complex could be achieved
using PCR directed to this region.
PMID- 9765823
TI - Exchange of Pseudomonas aeruginosa strains among cystic fibrosis siblings.
AB - The molecular epidemiology of Pseudomonas aeruginosa infection in cystic fibrosis
(CF) siblings was analysed by DNA fingerprinting using arbitrary primed
polymerase chain reaction. A total of 306 strains collected from six pairs of
siblings over a period of 20-126 months (median 64) was studied. Fifty-four
different P. aeruginosa genotypes were recognized. Two out of six pairs of
siblings were ultimately colonized by identical strains, and it was shown that a
single P. aeruginosa clone can persist in an individual patient for over ten
years. No overlap in P. aeruginosa genotypes was encountered between families,
whereas in all families at least transient cross-colonization with the same
genotype was observed. This finding demonstrates that P. aeruginosa cross
infection or acquisition of the same strain from an identical environmental
source exists within the family situation, but does not always result in a long
term colonization by identical genotypes in all family members suffering from CF.
PMID- 9765824
TI - Electrophoretic pattern of peptidoglycan hydrolases, a new tool for bacterial
species identification: application to 10 Lactobacillus species.
AB - Lactobacilli have been used as industrial starters for a long time, but in many
cases their phenotypic identification is still neither easy nor reliable.
Previously we observed that the cell wall peptidoglycan hydrolases of
Lactobacillus helveticus were highly conserved enzymes; the aim of the present
work was to determine whether peptidoglycan hydrolase patterns obtained by
renaturing SDS-PAGE could be of interest in the identification of lactobacilli
species. For that purpose, the peptidoglycan hydrolase patterns of 94 strains of
lactobacilli belonging to 10 different species were determined; most of the
species studied are used either in dairy, meat, bakery or vegetable
fermentations: L. helveticus, L. acidophilus, L. delbrueckii, L. brevis, L.
fermentum, L. jensenii, L. plantarum, L. sake, L. curvatus and L. reuteri. Within
a species, the strains exhibited highly similar patterns: the apparent molecular
weights of the lytic bands were identical, with only slight variations of
intensity. Moreover, each species, including phylogenetically close species such
as L. sake and L. curvatus, or L. acidophilus and L. helveticus, gave a different
pattern. Interestingly, the closer the species were phylogenetically, the more
related were their patterns. The sensitivity of the method was checked using
various quantities of L. acidophilus cells: a peptidoglycan hydrolase extract of
5 x 10(6) cells was sufficient to obtain an informative pattern, as was a single
colony. Finally, the method was also successfully applied to distinguish two
Carnobacterium species. In conclusion, the electrophoretic pattern of
peptidoglycan hydrolases is proposed as a new tool for lactobacilli
identification: it is rapid, sensitive and effective even for phylogenetically
close species. Furthermore, this work provides the first evidence of the
potential overall taxonomic value of bacterial peptidoglycan hydrolases.
PMID- 9765825
TI - Relationship between the physiology of Enterobacter agglomerans CNCM 1210 grown
anaerobically on glycerol and the culture conditions.
AB - In a preliminary study, levels of activity of enzymes involved in anaerobic
glycerol catabolism by Enterobacter agglomerans grown in batch cultures regulated
in a pH range of 6.5-8.0 were monitored. That study showed that activities of key
enzymes of the downstream metabolism of glycerol--glyceradehyde-3-phosphate
dehydrogenase (GAP-DH), lactate dehydrogenase and pyruvate formate lyase--were
strongly dependent on the culture pH. To investigate the influence of pH on the
physiology of the strain, E. agglomerans was grown anaerobically in a continuous
culture supplied with glycerol as the sole carbon source and regulated at pH 8. A
complete biochemical analysis was performed and was compared with that previously
described for the continuous culture regulated at pH 7. A limitation of the
glycolytic flux at the level of GAP-DH was demonstrated at high dilution rate,
resulting in an overflow metabolism through the 1,3-propanediol formation
pathway. Increasing the specific rate of glycerol consumption also resulted in
enhanced lactate production due to limitation by the pyruvate decarboxylation
step. Finally, changing the culture pH significantly modified the enzymatic
profile of E. agglomerans, and it enabled the stability of the culture to be
increased by preventing the accumulation in the fermentation broth of 3
hydroxypropionaldehyde, an inhibitory metabolite, when the glycerol supply was
suddenly increased.
PMID- 9765826
TI - A nested PCR method to detect Listeria monocytogenes in artificially contaminated
blood specimens.
AB - A nested PCR-based test was developed for the detection of Listeria monocytogenes
in blood specimens from patients with listeriosis. Two pairs of oligonucleotide
primers were designed to amplify a 1395-bp and a 453-bp fragment of the iap gene
of L. monocytogenes. Amplified products were analysed with gel electrophoresis
and stained with ethidium bromide. The PCR method described could be routinely
used to diagnose listeriosis.
PMID- 9765827
TI - Glycolipid antigen for use in diagnostic assays for bovine tuberculosis.
AB - A glycolipid antigen, was isolated, purified and characterized from Mycobacterium
bovis An5. Chemical analysis (thin-layer chromatography, nuclear magnetic
resonance and infrared spectra) showed that this glycolipid was a 2,3-di-O-acyl
trehalose (DAT), similar to the DAT of M. tuberculosis. This antigen was used to
establish ELISA-based serodiagnostic tests for M. bovis-infected cattle. The
sensitivity and specificity of the assay were investigated using sera of cattle
from tuberculosis-free herds and from tuberculosis-infected herds. No correlation
was found between DAT-ELISA and the skin test, nor between DAT-ELISA and
interferon-gamma with bovine purified protein derivative. The antibody titres
were not related to cell-mediated immunity. Although the antigen was highly
specific (95.9%), the sensitivity of DAT-ELISA, as judged from assays in
bacteriologically confirmed tuberculosis, was low (29 to 36.8%). The low
sensitivity of ELISA might also be attributed to a reciprocal relationship
between B-cell proliferation and T-cell protective immunity.
PMID- 9765828
TI - Genotyping of Lactobacillus delbrueckii subsp. bulgaricus and determination of
the number and forms of rrn operons in L. delbrueckii and its subspecies.
AB - Three different approaches (whole-cell protein profiles, DNA fingerprinting
combined with pulsed-field gel electrophoresis and analysis of rDNA genes) were
used to characterize thirty-one strains of Lactobacillus delbrueckii subsp.
bulgaricus from different dairy products, and three type strains belonging to L.
delbrueckii subsp. delbrueckii, L. delbrueckii subsp. lactis and L. delbrueckii
subsp. bulgaricus. Moreover, the number and different forms of rrn operons in L.
delbrueckii and its subspecies were defined. At the strain typing level, Notl
macrorestriction analysis permitted grouping of the 32 strains of L. delbrueckii
subsp. bulgaricus into 23 restriction patterns, providing a high degree of
discriminatory power. Among whole-cell protein profiles, PCR analysis of rDNA
genes and ribotyping, the latter method seemed to be the most reliable approach
to characterizing the subspecies belonging to L. delbrueckii. Ribotyping combined
with enzymes such as HindIII and EcoRI showed that at least six rrn operons were
present in L. delbrueckii and its subspecies; two forms of rrn operons were
present in the subspecies lactis and bulgaricus and four forms were present in
the subspecies delbrueckii.
PMID- 9765829
TI - Metal biosorption: a structured data space?
PMID- 9765830
TI - Recent advances in the mechanistic understanding of metal mobility and
interaction with microbial biomass.
PMID- 9765831
TI - Fundamentals of the application of biosorption to the separation of uranium from
mining drainage waters.
PMID- 9765832
TI - Engineering polysaccharides for biosorption of heavy metals at oil/water
interfaces.
PMID- 9765834
TI - Membrane processes in the resistance of microorganisms to heavy metals.
PMID- 9765833
TI - Flotation process for the recovery of metals and for the biodecontamination of
waters and soils contaminated by the Chernobyl accident.
PMID- 9765835
TI - The use of an Alcaligenes eutrophus biofilm in a membrane bioreactor for heavy
metal recovery.
PMID- 9765836
TI - Bioaccumulation of heavy metals, and application to the remediation of acid mine
drainage water containing uranium.
PMID- 9765837
TI - Microbially-mediated reduction and removal of technetium from solution.
PMID- 9765838
TI - Cell-based biosensors for environmental monitoring with special reference to
heavy metal analysis.
PMID- 9765839
TI - Bacterial metal-lux biosensors for a rapid determination of the heavy metal
bioavailability and toxicity in solid samples.
PMID- 9765840
TI - Alcaligenes eutrophus as a model system for bacterial interactions with heavy
metals in the environment.
PMID- 9765841
TI - Group A streptococcal isolate 64/14 expresses surface plasmin-binding structures
in addition to Plr.
AB - A recombinant plasmin receptor (Plr) gene product originally cloned from group A
streptococcal isolate 64/14 was analysed for its ability to bind plasmin(ogen)
and to account for all the surface plasmin-binding properties of streptococcal
isolate 64/14. Functional analysis of recombinant Plr demonstrated that the
protein exhibited equal reactivity with human Lys-plasmin and Lys-plasminogen,
but significantly lower reactivity with Glu-plasminogen. Plasmin-binding was both
inhibitable and elutable by lysine or lysine analogs, and active plasmin bound to
recombinant Plr was not neutralized by alpha 2-antiplasmin. Thus, the plasmin
binding properties of recombinant Plr correlated with the plasmin-binding
phenotype of the intact streptococcal isolate 64/14. In addition, fluid-phase
recombinant Plr could completely inhibit binding of plasmin to either immobilized
recombinant Plr or group A streptococcal isolate 64/14 with equal efficiency,
indicating that surface-expressed Plr could account for all the plasmin-binding
properties of the intact organism. An IgM monoclonal antibody to recombinant Plr
that specifically recognized a surface structure on streptococcal isolate 64/14
significantly inhibited the binding of plasmin to the recombinant protein;
however, the antibody was not successful at inhibiting plasmin-binding to the
intact bacteria, indicating the presence of other plasmin-binding structures on
the bacterial surface in addition to Plr.
PMID- 9765842
TI - Comparative analysis of the genomic DNA terminal regions of the lactococcal
bacteriophages from species c2.
AB - In an attempt to compare the cos intergenic region and bordering ORFs from
Lactococcus lactis bacteriophages of the species c2, the nucleotide sequence of a
2479-bp fragment containing the cos site of phage P001 DNA was determined and
compared with the corresponding regions of phages c2, bIL67 and P6 (partial
sequence), which belong to species c2. This comparative analysis revealed that
some characteristic features of the cos intergenic region are conserved in all
members of species c2. Some of them are specific to species c2, as is the case
for a GC-rich repeat in phase with the double helix that is located close to cos.
One conserved motif seems to be more general, as it is found in all the cos
regions of L. lactis bacteriophages that have been sequenced. It consists in a 4
nt indirect repeat TCAN/NACT located in a 15-bp fragment containing cos. This
motif may be related to terminase specificity, as most of the cos asymmetric
cleavages identified up to now are located within, or at the border of, these
indirectly repeated sequences. Finally, some of the conserved DNA motifs of the
species c2 cos-intergenic region seem to be even more general, as they are
homologous to the lambda-R sites known to be involved in the maturation and the
encapsidation of phage lambda DNA. Our comparative analysis also showed that
within c2 phage DNAs, large blocks of sequences, i.e. the intergenic cos region
and ORF/17 on the one hand, and ORF/16 on the other hand, evolved as distinct
entities, probably by block recombination between phage DNAs of the same species.
PMID- 9765843
TI - Mu gem2ts DNA integration is not necessary for induction of synchrony of cell
division in Escherichia coli K12.
AB - The gem2ts mutant of bacteriophage Mu induced synchrony of cell division on
bacteria surviving infection. Induction of synchronous growth could also be
observed as a response to the entire infected bacterial population, as in the
case of infection of hic mutants, a peculiar class of gyrB alleles. After Mu wild
type or Mu gem2ts infection of hic mutants, there was a lack of viral DNA
integration and replication, while phage gene expression (including that of A
gene, coding for the transposase) seemed to be quite normal. These data indicate
that the mechanism of bacterial synchronization induced by Mu gem2ts does not
require integration nor replication of the phage DNA.
PMID- 9765844
TI - Initial steps of wall protoplast regeneration in Candida albicans.
AB - Cell wall regeneration of individual Candida albicans yeast and mycelial
protoplasts was studied with confocal and electron microscopy using polyclonal
antibodies and lectins. Quantitative measurements of the fluorescence emitted by
individual protoplasts during the process of regeneration indicate that chitin is
the first polymer to be laid down, whereas beta (1,3)- and beta (1,6)glucan are
incorporated at a later stage. Mannoproteins were found on the surface of fresh
protoplasts and those newly synthesized were then deposited with time. During the
first steps of wall regeneration, the proteins that interacted covalently with
chitin or glucan were different, but the same species were found linked to each
polymer in yeast and mycelial regenerating forms. The aggregates formed by
regenerating protoplasts were shown to be due to the chitin and mannoprotein
network initially laid.
PMID- 9765845
TI - Genotypic diversity and typing of cyanobacterial strains of the genus Arthrospira
by very sensitive total DNA restriction profile analysis.
AB - Arthrospira maxima and A. platensis are two species of cyanobacteria cultivated
and sold as health food, animal feed and source of food additives and fine
chemicals. The genotypic diversity of several strains attributed to these two
species on the basis of morphological criteria was investigated using very
sensitive total DNA restriction profile analysis. The restriction profiles were
obtained after sodium dodecyl sulphate polyacrylamide gel electrophoresis and
silver staining. The unweighted pair-group method using arithmetic averages
applied to the matrix of Dice similarity coefficient values clustered the
electropherograms of the strains in two well-separated genotypic groups. These
clusters corresponded to those obtained with morphological criteria. The
molecular approach used was also able to type the examined strains.
PMID- 9765846
TI - Genetic and biochemical characterization of Saccharomyces cerevisiae mutants
resistant to trifluoroleucine.
AB - Eighteen mutants resistant to 5',5',5'-trifluoroleucine (TFL), a leucine analog,
were isolated in Saccharomyces cerevisiae strains YNN281 and YNN282. The mutants
were characterized genetically and clustered in two groups, one comprising all
the dominant (TFL1) and the other one all the recessive (tfl2) mutations. Genetic
and biochemical data suggested that the dominant mutations are located on the
LEU4 gene, coding for alpha-isopropylmalate synthase I. These mutations resulted
in accumulation of leucine as a consequence of the synthesis of an enzyme
insensitive to the feedback inhibition by leucine. Leucine excretion in the TFL1
mutants appeared to be affected by the genetic background of the strain and was
greatly influenced by lysine metabolism. The measurement of intra- and
extracellular amino acid concentrations in prototrophic strains carrying TFL1 or
tfl2 genes showed that both were leucine overproducers. Some of the TFL-resistant
mutants were tested in alcoholic fermentation of grape must: analysis of the
fermentation secondary metabolites showed that the major effect of the TFL
resistant strains was an increased production of isoamyl alcohol compared to that
of the parental strain.
PMID- 9765847
TI - The role of the capsular polysaccharide of Aeromonas hydrophila serogroup O:34 in
the adherence to and invasion of fish cell lines.
AB - The ability of Aeromonas hydrophila serogroup O:34 strains grown under different
conditions (capsulated and non-capsulated) to adhere to and invade two fish cell
lines was compared. The level of adherence was slightly higher when the strains
were grown under conditions promoting capsule formation than when the same
strains were grown under conditions which did not promote capsule formation.
However, the most significant difference among the wild-type strains grown under
conditions promoting capsule formation was the ability to invade the fish cell
lines, which was significantly higher than when the same strains were grown under
conditions which did not promote capsule formation. Isogenic unencapsulated
mutants grown under conditions promoting capsule formation showed a lower ability
to invade the fish cell lines than the parental capsulated strains. From these
results, we concluded that the capsular polysaccharide is an important factor in
intracellular invasion.
PMID- 9765848
TI - Molecular epidemiological investigation of Salmonella typhimurium strains related
to an egg-borne outbreak.
PMID- 9765849
TI - Participation of host gene functions in plasmid postsegregational killing: how
and why.
PMID- 9765850
TI - Universal ribotyping method using a chemically labelled oligonucleotide probe
mixture.
AB - Some of the present problems in ribotyping are associated with a lack of uniform
reactivity of probes when bacterial DNAs are of phylogenetically diverse origins.
To overcome these problems, a set of five oligonucleotides (referred to as
OligoMix5) was selected to react with conserved sequences located near both
extremities of rrs (16S rRNA gene) and near both extremities and the middle of
rrl (23S rRNA gene). DNA samples from 13 bacterial species selected to represent
various phylogenetic branches within the Eubacteria were cleaved by a restriction
endonuclease and electrophoresed in 0.8% agarose, and the fragments were vacuum
transferred to nylon membranes and hybridized with digoxigenin-labelled
OligoMix5, plasmid DNA from pKK3535 (cloned rrn operon from Escherichia coli) or
pBA2 (cloned rrs from Bacillus subtilis), or acetylamino-fluorene-labelled E.
coli 16 + 23S rRNA. The results showed OligoMix5 to visualize patterns in DNA
from phylogenetically diverse bacteria with comparable intensity. Banding
patterns (not band intensity) obtained with OligoMix5 were identical with those
obtained with 16 + 23S rRNA or plasmid pKK3535 for each strain studied and
represented complete ribotypes. For DNA from Gram-positive bacteria, complete
ribotypes were observed after prolonged enzymatic detection of bands when probes
were either E. coli 16 + 23S rRNA or pKK3535. Patterns given by plasmid pBA2 were
subsets of the complete ribotypes for 9/13 strains. Each oligonucleotide of the
OligoMix5 set was used as a probe to determine its contribution to the complete
ribotype. The five oligonucleotide probes, used individually, visualized one to
four patterns per DNA sample. Use of DNA from Xenorhabdus sp. CIP 105189 cleaved
by EcoRI is suggested to control the quality of the oligonucleotide probes
composing OligoMix5. Probe OligoMix5 was found to be an essential tool for
ribotyping phylogenetically diverse eubacteria.
PMID- 9765851
TI - Endo-N-acetyl-beta-D-glucosaminidases and their potential substrates:
structure/function relationships.
AB - Endo-N-acetyl-beta-D-glucosaminidases (ENGases) have been defined as the enzymes
that hydrolyse the glycosidic bond between an N-acetyl-beta-D-glucosamine residue
and the adjacent (partner) monosaccharide within an oligosaccharide chain. Three
types of enzymes have been distinguished according to this definition: ENGases
acting on murein (type I), those acting on chitin (type II) and, finally, those
acting on N-glycans (type III). Considering that N-acetylmuramic acid is a
derivative of N-acetylglucosamine (3-O-substituted by a lactyl group), only
ENGases acting between two N-acetylglucosamine residues are actually known
despite the fact that other possibilities of partner monosaccharides for N-acetyl
beta-D-glucosamine are reported. Similarities in the amino acid sequences were
found to occur only between chitin-ENGases and N-glycan-ENGases, but the
substrate specificities of these two types of enzymes are different. However, it
is possible that certain enzymes are able to cleave more than one type of
substrate, and this could in particular explain why the N-glycan-ENGases are
largely produced by bacteria in which no potential substrate for this type of
enzymes was identified. Further study in this area is expected.
PMID- 9765852
TI - Postantibiotic effect of amikacin, rifampin, sparfloxacin, clofazimine and
clarithromycin against Mycobacterium avium.
AB - Antimycobacterial drugs acting efficiently against Mycobacterium avium complex
have in common low MICs and MBC/MIC ratios. The recently reported clinical
efficacy of some of the newer drugs is also clearly linked to their
pharmacokinetic properties such as higher serum level and/or intracellular
concentrations and half-life. In the present investigation, comparative
postantibiotic effects (PAEs) of amikacin, rifampin, sparfloxacin, clofazimine
and clarithromycin were investigated. Bacteria were exposed to MIC, MIC x 4 and
MIC x 8 concentrations of each drug for 2 h, the drug was removed by
centrifugation and cells were thoroughly washed and resuspended in drug-free
medium. Growth was compared to control organisms which underwent a similar
treatment (but without drugs) and PAEs were assessed using the equation "T-C",
where T equals the time required for colony counts to increase by 1 log10 in test
samples after antibiotic exposure and C equals the time for 1 log10 growth in
control. Our results underlined two distinct patterns concerning PAE: pattern I
included drugs for which PAE (in hours) was dose-dependent and varied (for MIC,
MIC x 4 and MIC x 8 concentrations) for amikacin (10.3 +/- 1.7, 14.7 +/- 1.9 and
17.7 +/- 4.1), rifampin (28.0 +/- 7.6, 62.0 +/- 18.5 and 71.0 +/- 3.2) and
clarithromycin (2.6 +/- 1.0, 15.0 +/- 4.0 and 22.0 +/- 4.0), whereas pattern II
included drugs with a stable PAE, relatively independent of the drug
concentrations: sparfloxacin (11.0 +/- 2.5, 12.3 +/- 6.4 and 13.0 +/- 2.1) and
clofazimine (26.0 +/- 2.8, 28.8 +/- 2.5 and 27.3 +/- 1.3). These results may be
useful for guidance in scheduling of drug administration in M. avium-infected
AIDS patients overburdened with too many drugs given for various opportunistic
infections.
PMID- 9765853
TI - Mycobacterium avium complex strains from AIDS patients belong to a homogeneous
group ascribed by rRNA typing methods.
AB - 16S rRNA RFLP analysis of Mycobacterium avium complex (MAC) strains isolated from
25 AIDS patients led to identification of seven ribotypes. The same ribotype was
determined for strains from 19 patients with and without disseminated disease.
When isolates representing the seven ribotypes were examined for their internal
transcribed spacer (ITS) between the 16S and 23S rRNA gene nucleotide sequence,
four different sequences, including a new ITS type, were recovered. All isolates
with the most common ribotype belonged to the sequevar Mav-B. When MAC strains
from AIDS patients were compared by ITS sequencing and ribotyping, a significant
degree of homogeneity was observed. The discriminatory level reached with
ribotyping might be useful for grouping isolates from different clinical sources.
PMID- 9765855
TI - Computer-assisted analysis of Mycobacterium avium fingerprints using insertion
elements IS1245 and IS1311 in a Caribbean setting.
AB - A total of 33 clinical isolates of the Mycobacterium avium complex from 25
patients, identified by means of biochemical and cultural characteristics, the
Accuprobe system and DT1/DT6 PCR, were further analysed using novel insertion
elements IS1245 and IS1311 in a French Caribbean setting. PvuII-cleaved DNA and
non-radioactive Southern hybridization and detection systems were used for
fingerprinting with both IS elements. The data confirmed the specificity of the
two probes for M. avium in our setting and highlighted a significant proportion
of M. intracellulare-infected patients in this region. Two distinct groups
composed of 2-3 bands and 6-27 bands were found among M. avium isolates, and were
composed of the same isolates both with IS1245 and IS1311. The computer analysis
of polymorphic banding patterns identified two prevalent genotypes: one contained
4 isolates from 3 patients while a second 2-banded cluster was composed of 6
isolates from 4 patients; all the patients were from the same hospital in
Guadeloupe. A single isolate from Martinique was falsely included in the 2-banded
cluster initially upon IS1245 fingerprinting, but could be discriminated from
other isolates on the basis of IS1311 fingerprinting of PvuII-cleaved DNA. These
results were also confirmed upon IS1245 fingerprinting of PstI-digested DNA, as
well as DT6 fingerprinting. A single case of polyclonal infection was also
discovered in a patient at a 75-day interval. This is the first study comparing
the two IS elements and constitutes a first description of disseminated M. avium
complex disease from the Caribbean. We conclude that both elements possess a
similar discriminatory potential for M. avium isolates. Coupled with computer
analysis, this methodology would appear to be particularly suitable for larger
epidemiological studies.
PMID- 9765854
TI - Borrelia burgdorferi sensu lato in Russia and neighbouring countries: high
incidence of mixed isolates.
AB - A total of 365 isolates of Borrelia burgdorferi sensu lato from 12 major
administrative territories of Russia (from St. Petersburg in the west to South
Sakhalin in the east) and from the Czech Republic, Estonia, Lithuania,
Byelorussia, Moldavia, Ukraine and Kirghizia were identified by analysis of
restriction polymorphism of ribosomal rrf-rrl spacer amplicons. The isolates were
obtained mainly from ixodes persulcatus and I. ricinus ticks. Other sources
included small mammals, human patients and I. trianguliceps ticks. The results
showed that B. garinii (two variants) together with B. afzelii circulated
throughout the territories studied. The distribution of the variant NT29 of the
species B. garinii, the most frequently isolated, was associated with that of I.
persulcatus ticks. B. burgdorferi sensu stricto, and the species B. valaisiana
and B. lusitaniae (formerly the genomospecies VS116 and PotiB2, respectively)
were isolated only from I. ricinus ticks in the western part of the studied
territories. None of these three species were found in 327 isolates from Russia
where I. persulcatus is the most frequently distributed vector. This work also
provides evidence for a high incidence of mixed Borrelia infections within
vectors and hosts (9.3% of isolates were mixtures of Borrelia species). A
detailed analysis of Borrelia species distribution over the territories studied
is presented.
PMID- 9765856
TI - Identification of atypical strains of Staphylococcus epidermidis by use of
molecular tools.
AB - Four atypical coagulase-negative staphylococcal (CNS) isolates from clinical
sources were compared with Staphylococcus epidermidis strains by ribotyping. The
ribotypes of the four strains shared close rDNA restriction profiles with those
of the S. epidermidis strains used. The DNA sequence encoding 16S rRNA
demonstrated 99.9% homology with S. epidermidis. S1 nuclease experiments showed
that these atypical strains formed a homogeneous genomic group. DNA-DNA
homologies between the S. epidermidis type strain CCM 2124 and the four CNS
isolates ranged from 70 to 89%. The guanine-plus-cytosine content of the
deoxyribonucleic acid of the four strains ranged from 31 to 32 mol%.
PMID- 9765857
TI - Trinucleotide repeats in yeast.
AB - The yeast genome exhibits a variety of trinucleotide repeat arrays within protein
coding genes and intergenic regions. In the first situation, repeats are often
not random relative to the translational frame, resulting preferably in long
stretches of the two acidic amino acids or of their corresponding amine forms.
Interestingly, the longest trinucleotide repeats are often found in genes
encoding nuclearly located proteins. Repeats tend to be more frequent in long
genes, but less frequent among members of gene families compared to unique genes.
In the latter case, repeat arrays often differ in length or composition between
the gene homologs, indicating their instability.
PMID- 9765858
TI - Detection of pap, sfa and afa adhesin-encoding operons in uropathogenic
Escherichia coli strains: relationship with expression of adhesins and production
of toxins.
AB - A total of 243 Escherichia coli strains isolated from patients with urinary tract
infections (UTI) were investigated for the presence of pap, sfa and afa adhesin
encoding operons by using the polymerase chain reaction. It was found that 54%,
53% and 2% of the strains exhibited the pap, sfa and afa genotypes, respectively.
Pap+ and/or sfa+ strains were more frequent in cases of acute pyelonephritis
(94%) than in cases of cystitis (67%) (P < 0.001) and asymptomatic bacteriuria
(57%) (P < 0.001). The pap and/or sfa operons were found in 90% of strains
expressing mannose-resistant haemagglutination (MRHA) versus 37% of MRHA-negative
strains (P < 0.001). The presence of pap and sfa operons was especially
significant in strains belonging to MRHA types III (100%) (without P adhesins)
and IVa (97%) (expressing the specific Gal-Gal binding typical of P adhesins).
Both pap and sfa operons were closely associated with toxigenic E. coli producing
alpha-haemolysin (Hly+) and/or the cytotoxic necrotizing factor type 1. There was
an apparent correlation between the pap and sfa operons and the O serogroups of
the strains. Thus, 93% of strains belonging to O1, O2, O4, O6, O7, O14, O15, O18,
O22, O75 and O83 possessed pap and/or sfa operons, versus only 32% of strains
belonging to other serogroups (P < 0.001). The results obtained in this study
confirm the usefulness of our MRHA typing system for presumptive identification
of pathogenic E. coli exhibiting different virulence factors. Thus, 85% of
strains that possessed both pap and sfa adhesin-encoding operons showed MRHA
types III or IVa previously associated with virulence of E. coli strains that
cause UTI and bacteraemia.
PMID- 9765859
TI - Evidence for a bacteriocin-like substance produced by a new strain of
Streptococcus sp., inhibitory to gram-positive food-borne pathogens.
AB - A new strain of Streptococcus sp. (CNCM I-841) isolated from a commercial
probiotic product was shown to be antagonistic towards several food-borne
pathogens including Clostridium sp. and Listeria monocytogenes. This strain
produced and excreted an antibacterial substance in MRS broth. The inhibitory
substance was different from hydrogen peroxide, since it was unaffected by
catalase. It was sensitive to proteolytic enzymes, indicating that the active
moiety of the inhibitor was proteinaceous in nature, and it had no effect on its
producer strain. These properties suggested that the inhibitory substance could
be considered as a bacteriocin-like substance. The antimicrobial substance was
also produced in M17 and tryptose broths if they were supplemented with Tween-80.
Partial purification allowed a 10.5-fold increase in the specific activity. A
preliminary characterization showed that it was active against lactobacilli,
Enterococcus faecalis, Clostridium sp. and Listeria sp. It was not affected by 2
h treatment at 60 degrees C, but was sensitive to treatments at 100 degrees C and
to autoclaving at 121 degrees C. The activity was not affected by treatments at
pH values ranging from 2 to 11.
PMID- 9765860
TI - Isolation of new plasmids from hyperthermophilic Archaea of the order
Thermococcales.
AB - A collection of 57 strains of hyperthermophilic Archaea from the order
Thermococcales was screened for the presence of plasmids; 9 plasmids present in
six of these strains were isolated and characterized in terms of size and cross
hybridization. The Notl macrorestriction patterns of genomic DNA of strains
harbouring these plasmids were obtained. Pyrococcus abyssi strains GE27 and GE23
as well as Thermococcus sp. GE31 contained a single plasmid of 3.5 kb (pGN27),
16.8 kb (pGN23) and 5.3 kb (pGN31), respectively, whilst the three strains I559,
I560 and I690 all contained two plasmids of 3.5 kb (pSN559, pSN560, pSN690) and
24 kb (pLN559, pLN560, pLN690), respectively. Plasmid pGN27 strongly cross
hybridized with the previously described plasmid pGT5 from P. abyssi strain GE5,
whilst plasmids pGN23 and pGN31 did not cross-hybridize with each other, nor with
any other plasmid. The three small plasmids of strains I559, I560 and I690 cross
hybridized, as well as their three large plasmids. Macrorestriction pattern
analysis and the results of plasmid cross-hybridization experiments indicated
that these three strains were different but closely related, and likely belonged
to the genus Thermococcus. This study shows that plasmids are widespread in
hyperthermophilic archaea, and significantly increases the number and diversity
of plasmids available for laboratory work.
PMID- 9765861
TI - PCR-amplified 16S and 23S rDNA restriction analysis for the identification of
Acinetobacter strains at the DNA group level.
AB - The genus Acinetobacter is phenotypically rather homogeneous, but genotypically
heterogeneous. In this study, a simple method based on restriction analysis of a
PCR-amplified large fragment (4.5 kb) of most of the ribosomal operon (16S and
23S ribosomal genes and the spacer in-between) was investigated. Sixty-seven
collection strains belonging to the 20 DNA groups proposed until 1993 were
studied. Using the enzyme Sau3AI, 25 DNA profiles were obtained. Strains
belonging to DNA groups 1, 3, 6, TU13 and TU15 showed two profiles each, and DNA
groups 4, 5 and 7 showed profiles with variants showing less intensive additional
bands. The remaining 12 groups showed 12 different profiles. The profiles
obtained were DNA-group-specific except for one profile which was shared between
the unnamed DNA group 3 and a rarely encountered genotypically related DNA group.
These two DNA groups could be separated by using the enzyme Hinf1. Twenty-five
additional clinical isolates previously characterized by standard DNA-DNA
hybridization were selected in a double-blind fashion for identification at the
DNA group level to check the reliability of the assay. All strains were correctly
identified at the DNA group level. PCR-amplified 16S and 23S rDNA restriction
analysis is both an accurate and rapid method for the identification of
Acinetobacter at the DNA group level.
PMID- 9765862
TI - The relationship between microbial metabolic activity and biocorrosion of carbon
steel.
AB - The effect of metabolic activity (expressed by generation time, rate of H2S
production and the activity of hydrogenase and adenosine phosphosulphate (APS)
reductase enzymes) of the 8 wild strains of Desulfovibrio desulfuricans and of
their resistance to metal ions (Hg2+, Cu2+, Mn2+, Zn2+, Ni2+, Cr3+) on the rate
of corrosion of carbon steel was studied. The medium containing lactate as the
carbon source and sulphate as the electron acceptor was used for bacterial
metabolic activity examination and in corrosive assays. Bacterial growth
inhibition by metal ions was investigated in the sulphate-free medium. The rate
of H2S production was approximately directly proportional to the specific
activities of the investigated enzymes. These activities were inversely
proportional to the generation time. The rate of microbiologically induced
corrosion (MIC) of carbon steel was directly proportional to bacterial resistance
to metal ions (correlation coefficient r = 0.95). The correlation between the MIC
rate and the activity of enzymes tested, although weaker, was also observed (r =
0.41 for APS-reductase; r = 0.69 for hydrogenase; critical value rc = 0.30, p =
0.05, n = 40).
PMID- 9765863
TI - Enhanced mineralization of UL-14C-pentachlorophenol by mushroom composts.
PMID- 9765864
TI - Identification of Rhodococcus, Gordona and Dietzia species using carbon source
utilization tests ("Biotype-100" strips).
AB - The "Biotype-100" identification system (BioMerieux, La Balme-Ies-Grottes,
France) based on carbon source utilization was evaluated for its ability to
discriminate among 10 species of Rhodococcus, 7 species of Gordona and one
species of Dietzia. The type strains of three species of Tsukamurella and 8
species of Nocardia were also included in the study. Results were compared with
chemotaxonomic and conventional data. Carbon source utilization was shown to be
reliable, rapid and easy to use when compared with standard identification
methods. The 29 species tested were unambiguously separated by carbon source
utilization tests. Rhodococcus equi was found to be heterogenous.
PMID- 9765865
TI - Supplement 1996 (no. 40) to the Kauffmann-White scheme.
AB - This supplement reports the characterization of 13 new Salmonella serovars
recognized in 1996 by the WHO Collaborating Centre for Reference and Research on
Salmonella: 8 were assigned to S. enterica subsp. enterica, 3 to subspecies
salamae and 2 to subspecies diarizonae.
PMID- 9765866
TI - Peptide metabolism in cytoplasm of brain cells.
PMID- 9765867
TI - Mechanistic and structural studies on methylmalonyl-CoA mutase.
PMID- 9765868
TI - Swinging arms in multifunctional enzymes and the specificity of post
translational modification.
PMID- 9765869
TI - S-adenosylmethionine: a 'poor man's coenzyme B12' in the reaction of lysine 2,3
aminomutase.
PMID- 9765870
TI - Enzymes that exploit imines--one way or the other.
PMID- 9765871
TI - Preparation and properties of 6-substituted cyclohexane-1,2,4-triol derivatives:
mechanistic probes for the inositol monophosphatase reaction.
PMID- 9765872
TI - A discussion on the activation of oxygen in chemistry and enzymology.
PMID- 9765874
TI - Why has phosphatidylethanolamine N-methyltransferase survived in evolution?
PMID- 9765873
TI - Structure and mechanism of enzymes involved in the assembly of the tetrapyrrole
macrocycle.
PMID- 9765876
TI - Activation of calcium-independent phospholipase A2 by depletion of internal
calcium stores.
PMID- 9765875
TI - Binding of bee venom and human group IIa phospholipases A2 to membranes: a minor
role for electrostatics.
PMID- 9765877
TI - Regulation of cytosolic phospholipase A2 by phosphorylation.
PMID- 9765878
TI - The structure of phospholipase C isoforms and the regulation of phosphoinositide
hydrolysis.
PMID- 9765879
TI - The effects of phospholipid structure on the function of a calcium pump.
PMID- 9765880
TI - Why is docosahexaenoic acid essential for nervous system function?
PMID- 9765881
TI - The role of lysophosphatide acyltransferases and protein kinase C isoforms in the
regulation of lymphocyte responses.
PMID- 9765882
TI - The non-specific lipid transfer protein (sterol carrier protein 2) acts as a
peroxisomal fatty acyl-CoA binding protein.
PMID- 9765883
TI - Anionic phospholipids and the regulation of cell functions.
PMID- 9765884
TI - Consideration of a phlorin structure for haem P-460 of hydroxylamine
oxidoreductase and its implications regarding reaction mechanism.
PMID- 9765885
TI - Dimethylsulphoxide reductase from purple phototrophic bacteria: structures and
mechanism(s).
PMID- 9765886
TI - Structural bases for the catalytic mechanism of [NiFe] hydrogenases.
PMID- 9765887
TI - The diversity of redox proteins involved in bacterial heterotrophic nitrification
and aerobic denitrification.
PMID- 9765888
TI - The membrane-integral domain of succinate:quinone oxidoreductases--a secretive
haem-containing domain.
PMID- 9765889
TI - The pyrroloquinoline quinone (PQQ)-containing quinoprotein dehydrogenases.
PMID- 9765890
TI - Structure and function of flavocytochrome c3, the soluble fumarate reductase from
Shewanella NCIMB400.
PMID- 9765891
TI - Protein engineering of the photoreaction centre from Rhodobacter sphaeroides.
PMID- 9765892
TI - Towards structural genomics for transmembrane proteins.
PMID- 9765893
TI - Molecular dynamics simulations of membranes with embedded proteins and peptides:
porin, alamethicin and influenza virus M2.
PMID- 9765894
TI - Helical structure and dynamics in membrane polypeptides.
PMID- 9765895
TI - Three-dimensional models of glutamate receptors.
PMID- 9765896
TI - Fibrillogenesis of beta-amyloid.
PMID- 9765897
TI - Intraneuronal filamentous tau protein and alpha-synuclein deposits in
neurodegenerative diseases.
PMID- 9765898
TI - Polyglutamine expansion and Huntington's disease.
PMID- 9765899
TI - Copper, zinc superoxide dismutase (SOD1) and its role in neuronal function and
disease with particular relevance to motor neurone disease/amyotrophic lateral
sclerosis.
PMID- 9765900
TI - The three-dimensional structure of prion protein: implications for prion disease.
PMID- 9765901
TI - Amyloid fibres of Sup35 support a prion-like mechanism of inheritance in yeast.
PMID- 9765902
TI - Presenilins--in search of functionality.
AB - The discovery of the PS proteins, the complexities of their biochemistry and
their potential involvement in signalling pathways and in apoptosis have
galvanized research into AD. To date, the aspect of the functionality of the PSs
most relevant to the pathology of AD is the effect of PS FAD mutants to increase
the proportion of A beta 42 produced from cells. This, coupled to the observation
that gamma-secretase cleavage is considerably reduced in neurons derived from PS
1 knockout mice, argues strongly that PS plays a very direct role in the
proteolytic processing of APP.
PMID- 9765903
TI - The Fe65 and X11 families of proteins: proteins that interact with the
Alzheimer's disease amyloid precursor protein.
PMID- 9765904
TI - Characterization of beta-secretase.
PMID- 9765905
TI - Transgenic mouse models of Alzheimer's disease.
PMID- 9765906
TI - Modelling the packing of transmembrane helices: application to aquaporin-1.
PMID- 9765907
TI - Studies on the structure of a transmembrane region and a cytoplasmic loop of the
human red cell anion exchanger (band 3, AE1).
PMID- 9765908
TI - Structure of the G-protein-coupled receptor, rhodopsin: a domain approach.
PMID- 9765909
TI - Mechanistic aspects of energy coupling in the Escherichia coli mannitol
phosphotransferase system: a domain approach.
PMID- 9765910
TI - How cytidylyltransferase uses an amphipathic helix to sense membrane phospholipid
composition.
AB - CT responds to properties of PC-depleted membranes: increased negative charge
density, which concentrates the enzyme at the membrane surface, and lipid packing
perturbations, which create holes in the membrane surface into which the
hydrophobic side chains of the amphipathic helix of domain M can intercalate. The
PC-deficient lipid surface appears capable of catalysing the folding of domain M
into an alpha-helix. The determinants on domain M which create a preference for
anionic lipids are: (i) strips of interfacial lysines; (ii) three serines within
the non-polar face; (iii) three interfacial glutamates whose protonation state
appears to be sensitive to the surface charge. Phosphorylation of the domain
adjacent to domain M decreases the membrane affinity of the amphipathic helix,
perhaps by an ion-pairing competition. The mechanism whereby the stabilization of
an alpha-helical conformation of domain M is transduced into a conformational
change in the catalytic domain is the key question for future exploration.
PMID- 9765911
TI - The role of heparin in the complex formation between fibroblast growth factor 2
and its high affinity receptor: comparative modelling and biochemical studies.
PMID- 9765912
TI - Using HOLE to predict the effects of PEG's on the conductance of alpha-toxin.
PMID- 9765914
TI - Dynamic properties of ions in models of ion channels studied by molecular
dynamics simulation.
PMID- 9765913
TI - Studies on the transmembrane domain of phospholamban using rotational resonance
and magic angle oriented sample spinning (MAOSS) NMR spectroscopy.
PMID- 9765915
TI - Assessment of 'Metabolism' in an integrated medical curriculum.
PMID- 9765916
TI - Conductimetry for enzyme teaching.
PMID- 9765917
TI - Extracellular signal-regulated kinase 1 or 2 activation by Fc gamma RI
aggregation in U937 cells.
PMID- 9765918
TI - Ectopic expression of natural resistance-associated macrophage protein-1 in COS-1
cells modulates iron accumulation.
PMID- 9765919
TI - Fc-dependent immune regulation. Enhancement and/suppression directed by antibody
engaging functional Fc receptors (FcR).
PMID- 9765920
TI - Characterization of the Fc receptors (FcR) functioning as bridge between antibody
and cell-effector function: antibody-FcR-linked activation of immune
responsiveness.
PMID- 9765921
TI - Fc gamma receptors in negative signaling--as potential candidates for the
antibody induced regulation of humoral responses.
PMID- 9765922
TI - Leptin regulation of expression of neuropeptide Y and its receptor.
PMID- 9765923
TI - Effect of endotoxin on very-low-density lipoprotein metabolism in rat heart.
PMID- 9765924
TI - delta-Aminolevulenic acid (ALA) and the control of intestinal iron absorption.
PMID- 9765925
TI - Growth hormone regulation of mammary glucose.
PMID- 9765926
TI - Tissue-specific differences in rat glucocorticoid receptor gene transcriptional
regulation.
PMID- 9765927
TI - Heterotrophic nitrification in Paracoccus denitrificans.
PMID- 9765928
TI - Modification of the binding pocket for the QA ubiquinone in the reaction centre
from Rhodobacter sphaeroides.
PMID- 9765929
TI - Molecular structure of an unusual cytochrome c2 determined at 2.0 A; the
cytochrome cH from Methylobacterium extorquens.
PMID- 9765930
TI - Stopped-flow studies on dimethylsulphoxide reductase from Rhodobacter capsulatus:
kinetic competence of the dimethylsulphide-reduced intermediate.
PMID- 9765931
TI - The interaction of eukaryotic cytochrome b5 with flavocytochrome P-450 BM3 from
Bacillus megaterium.
PMID- 9765932
TI - Mechanistic probes of flavocytochrome P-450 BM3.
PMID- 9765933
TI - Electron-transferring flavoprotein from Megasphaera elsdenii; gene organisation
and structural information.
PMID- 9765934
TI - Characterization of the complex of isoFMN and apoflavodoxin from Desulfovibrio
vulgaris (Hildenborough).
PMID- 9765935
TI - The nrfEFG gene products are required for the activity of the cytochrome c552
nitrite reductase from Escherichia coli.
PMID- 9765936
TI - The periplasmic nitrate reductase of Escherichia coli--a comparison with the Nap
systems of other bacteria.
PMID- 9765938
TI - Cell proliferation and CTP:cholinephosphate cytidylyltransferase activity in
higher plants.
PMID- 9765937
TI - Sexual dimorphism in the fatty acyl composition of rat adrenal lipids.
PMID- 9765939
TI - Role of lipid peroxidation in the testicular damage in experimentally varicocele
induced rats.
PMID- 9765940
TI - Relationship between serum fatty acids and malondialdehyde (MDA) levels in
coronary artery disease diagnosed (CAD) patients.
PMID- 9765941
TI - S phase depletion of nuclear CTP:choline phosphate cytidylyltransferase.
PMID- 9765942
TI - Chromatin-associated phosphatidylcholine synthesis.
PMID- 9765943
TI - Diethylstilbestrol antagonizes the oxidant-induced transformations of membrane
phospholipids.
PMID- 9765944
TI - BipA affects Ca++ fluxes and phosphorylation of the translocated intimin receptor
(Tir/Hp90) in host epithelial cells infected with enteropathogenic E. coli.
PMID- 9765945
TI - Analysis of phosphatidic acid molecular species using mass spectrometry.
PMID- 9765946
TI - Molecular species of acidic phospholipids in human lung surfactant.
PMID- 9765948
TI - Effects of sphingosine 1-phosphate and bradykinin on phospholipid signalling in
human epithelial A549 cells.
PMID- 9765947
TI - Interaction of the SR CaATPase with the cytoplasmic region of phospholamban.
PMID- 9765949
TI - Modulation of CTP:phosphocholine cytidylyltransferase by membrane torque tension.
PMID- 9765950
TI - The okadaic acid induced ACAT activation is prevented by a specific inhibitor of
the Ca2+/calmodulin protein kinase II.
PMID- 9765951
TI - Expression of FAT, the putative fatty acid translocator protein, is
developmentally regulated in rat mammary tissue.
PMID- 9765952
TI - Activation of phospholipase A2 during differentiation of human haemopoietic
progenitor cells.
PMID- 9765953
TI - Anionic lipids and accumulation of Ca2+ by a Ca(2+)-ATPase.
PMID- 9765954
TI - Adrenaline induced inhibition of neutrophil PLA2 activity.
PMID- 9765955
TI - Phospholipase D enhances the hydrolysis of phospholipid vesicles by cytosolic
phospholipase A2.
PMID- 9765956
TI - Lipoprotein lipase hydrolysis of human lipoproteins measured using a fluorescence
displacement assay.
PMID- 9765957
TI - Liver fatty acid binding protein (FABP) binds to anionic phospholipid vesicles
with release of ligand.
PMID- 9765958
TI - Purification and properties of an active site mutant, H48Q, of human non
pancreatic secreted phospholipase A2.
PMID- 9765959
TI - beta-Amyloid toxicity in rat brain reaggregate cultures.
PMID- 9765960
TI - Detergent solubility and processing of the familial Alzheimer's disease-related
presenilin proteins.
PMID- 9765961
TI - The amyloid precursor protein (APP) and the angiotensin converting enzyme (ACE)
secretase are inhibited by hydroxamic acid-based inhibitors.
PMID- 9765962
TI - Full length huntingtin is not detected in intranuclear inclusions in Huntington's
disease brain.
PMID- 9765963
TI - Blood platelets do not contain the low-density receptor-related protein (LRP).
PMID- 9765964
TI - Molecular characterisation of the Alzheimer's amyloid precursor protein
secretases.
PMID- 9765965
TI - Stimulation of glyceraldehyde-3-phosphate dehydrogenase by oxyhemoglobin.
PMID- 9765966
TI - Soybean iron metabolism and nutrition.
PMID- 9765967
TI - The cloning and functional expression of human pancreatic aminopeptidase P.
PMID- 9765968
TI - Affinity purification of human IgG using immobilised, mutated immunoglobulin
binding domains from protein A of Staphylococcus aureus.
PMID- 9765969
TI - A chaperonin apical domain from the thermophilic bacterium Thermus Aquaticus.
PMID- 9765970
TI - Aluminosilicate particulate and beta-amyloid in vitro interactions: a model of
Alzheimer plaque formation.
PMID- 9765971
TI - Transcription factor, BTF3, and the AF-1 function of the estrogen receptor.
PMID- 9765972
TI - Regulation of macrophage lipoprotein lipase by cytokines.
PMID- 9765973
TI - Use of an antisense strategy to dissect the role of MAP kinases in cellular
signalling.
PMID- 9765975
TI - Pax-3: a role in embryonic cell division, cell morphology or neuronal
differentiation?
PMID- 9765974
TI - Role of CBP in glucocorticoid-induced gene repression.
PMID- 9765976
TI - Regulation of the paired box transcription factor Pax-3.
PMID- 9765977
TI - Regulation of herpes simplex virus immediate early gene expression.
PMID- 9765978
TI - Programmed cell death in skeletal muscle.
PMID- 9765979
TI - Glucose-dependent decreased DNA synthesis in bovine retinal endothelial cells is
mediated by protein kinase C iota.
PMID- 9765980
TI - DNA triple helix formation at (AT)n tracts.
PMID- 9765981
TI - Archaeal evidence for the role of 2' aminoacylation of RNA in the origin of amino
acid homochirality.
PMID- 9765982
TI - A proposed mechanism for the induction of activator protein 1 (AP-1) binding by
HIV-1 negative factor(Nef) in the macrophage cell line RAW267.4 cells.
PMID- 9765983
TI - Molecular cloning and characterisation of a novel duodenal-specific gene
implicated in iron absorption.
PMID- 9765984
TI - Identification of a novel PKD1 mutation in an Irish autosomal dominant polycystic
kidney disease kindred.
PMID- 9765985
TI - Studies of gene expression patterns in RER+ and RER- colon cancer cell lines.
PMID- 9765986
TI - Fibre type-specific expression of the calpain proteolytic system in skeletal
muscle.
PMID- 9765987
TI - Characterisation of 8-amino-7-oxononanoate synthase: a bacterial PLP-dependent,
acyl CoA condensing enzyme.
PMID- 9765988
TI - Cysteine conjugate beta-lyase activity of amino acid decarboxylases.
PMID- 9765990
TI - An investigation of flavoprotein redox partners.
PMID- 9765989
TI - Site-directed mutagenesis of the quinoprotein glucose dehydrogenase of
Escherichia coli; the role of His262 in PQQ binding and determination of
substrate specificity.
PMID- 9765991
TI - Chemical modification of histidine residues in human 'electron transferring
flavoprotein' (ETF).
PMID- 9765992
TI - Structure and function studies of oxalate oxidase.
PMID- 9765993
TI - Availability in pooled normal blood plasma of activated Hageman factor and
kallikrein for contact induced coagulation.
PMID- 9765994
TI - Two glycolytic enzymes from Sulfolobus solfataricus.
PMID- 9765995
TI - Degradation rates differ between mutant and wild-type forms of phenylalanine
hydroxylase expressed in vitro.
PMID- 9765996
TI - Identification of subunit interfaces of glycerol dehydrogenase from Bacillus
stearothermophilus.
PMID- 9765997
TI - Studies on the folding and unfolding of glycerol dehydrogenase from Bacillus
stearothermophilus.
PMID- 9765998
TI - Characterisation of domain fragments of recombinant human albumin.
PMID- 9765999
TI - Expression of recombinant aroB-encoded dehydroquinate synthase from pathogenic
microorganisms.
PMID- 9766000
TI - Site-directed mutants of the catalase-peroxidase from Mycobacterium tuberculosis.
PMID- 9766001
TI - Construction of a Pseudomonas aeruginosa cosmid library.
PMID- 9766002
TI - Molecular modelling of batroxobin on kallikreins.
PMID- 9766004
TI - Mechanistic studies on E.coli 5-aminolaevulinic acid dehydratase.
PMID- 9766003
TI - Incubation of 6-methylsalicylic acid synthase with alternative starter units in
the absence of NADPH and the identification of the resulting triaceticacid
lactones.
PMID- 9766005
TI - Dipyrromethane cofactor assembly in porphobilinogen deaminase.
PMID- 9766006
TI - Cloning, isolation, expression and mutagenesis studies on the human immuno
deficiency virus type 1 (HIV-1) protease.
PMID- 9766007
TI - Over-expression of the N-terminal domain of the glucagon-like peptide-1 receptor
in Escherichia coli.
PMID- 9766009
TI - The effects of thimerosal on the purified InsP3 receptor.
PMID- 9766010
TI - Cross-linking analysis of rabbit skeletal muscle dystrophin.
PMID- 9766008
TI - Role of Glut1 glucose transporter activation in stimulation of glucose transport
by A231876 and TPA.
PMID- 9766011
TI - Oligomerisation of calsequestrin from rabbit skeletal muscle.
PMID- 9766013
TI - Localisation and dynamics of receptor-insulin contacts by NMR studies on the
human insulin receptor ectodomain.
PMID- 9766014
TI - Use of cross-linking to investigate protein interactions with E. coli penicillin
binding protein 4.
PMID- 9766012
TI - Cellular localisation of the most common mutant form of the CF gene protein,
delta F508-CFTR.
PMID- 9766016
TI - Solid state NMR studies of ligands bound to the nicotinic acetylcholine receptor.
PMID- 9766015
TI - An investigation into the lipid interactions of peptides corresponding to the C
terminal anchoring domains of Escherichia coli penicillin-binding proteins 4 and
5.
PMID- 9766017
TI - Localization of endoplasmic reticulum in living cells using green fluorescent
protein chimeras.
PMID- 9766018
TI - Identification of endoplasmic reticulum targeting signals using SERCA/PMCA
chimeras.
PMID- 9766019
TI - Electrostatics of ligand-gated ion channels.
PMID- 9766020
TI - Molecular dynamics of ion/channel interactions.
PMID- 9766021
TI - Peptide-bilayer interactions:- simulation studies.
PMID- 9766022
TI - Simulations of the M2 channel for influenza A virus.
PMID- 9766023
TI - Cell-free synthesis and assembly of connexins into functional gap junction
hemichannels.
PMID- 9766024
TI - The effect of mastoparan on the E2-E1 transition of the SR Ca(2+)-ATPase.
PMID- 9766025
TI - Effect of the D32N and N300F mutations on the activity of the bacterial sugar
transport protein, GalP.
PMID- 9766026
TI - Interaction of calpastatin isoforms with L-type Ca2+ channels.
PMID- 9766027
TI - Structure and conformation of the retinal chromophore in bovine rhodopsin.
PMID- 9766028
TI - Transmembrane alpha-helices in phospholipid bilayers.
PMID- 9766029
TI - Flexible hinges in dystrophin.
PMID- 9766030
TI - Why inject contrast for magnetic resonance angiography?
PMID- 9766031
TI - Future directions of magnetic resonance angiography.
PMID- 9766032
TI - Determinants of image appearance in contrast-enhanced magnetic resonance
angiography. A review.
AB - The use of contrast agents in magnetic resonance (MR) studies of vascular
pathology has permitted the exploration of regions that were heretofore poorly
evaluated with conventional magnetic resonance angiography (MRA). An important
feature of contrast-enhanced MRA (CE-MRA) is the very short acquisition times
that are possible. The determination of the parameters to be used in a CE-MRA
study rests on an understanding of the dynamics of the passage of the injected
contrast agent and the response of the magnetization to the parameters of the MR
imaging sequence. An overview of this interaction is presented.
PMID- 9766033
TI - X-ray digital subtraction angiography to magnetic resonance-digital subtraction
angiography using three-dimensional TRICKS. Historical perspective and computer
simulations: a review.
AB - Seventeen years after the introduction of x-ray digital subtraction angiography
(DSA), gadolinium-enhanced magnetic resonance (MR) angiography techniques have
become available for the performance of MR-DSA. For the purposes of this article,
we will consider this to include two-dimensional and three-dimensional approaches
using time-resolved and non-time-resolved applications. Magnetic resonance-DSA is
one in a historical progression of techniques which have aimed to produce less
invasive forms of angiography. After outlining some historical milestones,
several current issues regarding current methods for MR-DSA are discussed.
PMID- 9766034
TI - Arterial-phase three-dimensional gadolinium magnetic resonance angiography of the
renal arteries. Strategies for timing and contrast media injection: original
investigation.
AB - RATIONALE AND OBJECTIVES: The authors review different imaging and contrast-media
infusion strategies for arterial-phase three-dimensional (3D) gadolinium-enhanced
magnetic resonance angiography (Gd-MRA). METHODS: The influence of
physicochemical factors on the infusion of contrast media, including viscosity,
flow rate, inline pressure, and cannula size, is assessed. The combination of
manual or automated contrast-media administration with timing-dependent or
independent 3D Gd-MRA techniques is reviewed regarding the aspects of
effectiveness, robustness, image quality, and costs. RESULTS: For effective bolus
delivery with high flow rates, the type and temperature of the contrast media,
the size of the cannula, and an immediate saline flush must be considered. Timing
dependent techniques based on a test bolus and using automated contrast-media
infusion as well as timing independent techniques such as MR SmartPrep or
multiphase 3D Gd-MRA by using a manual injection with a SmartSet tubing set, are
all effective procedures for arterial phase 3D Gd-MRA. CONCLUSIONS: Manual
contrast-media injection with a tubing set can be used for timing-independent MRA
techniques. The multiphase 3D Gd-MRA approach seems to be favorable for different
MR systems, robustness, and speed.
PMID- 9766035
TI - Optimization of gadolinium-enhanced magnetic resonance angiography using an
automated bolus-detection algorithm (MR SmartPrep). Original investigation.
AB - Gadolinium (Gd)-enhanced three-dimensional (3D) magnetic resonance angiography
(MRA) is a quick method for performing noninvasive diagnostic angiography. A
major technical obstacle to the successful implementation of this technique,
however, is the proper coordination of the data acquisition with the contrast
bolus. In this article, the use of an automated bolus-detection algorithm (MR
SmartPrep), which triggers the initiation of data acquisition for Gd-enhanced 3D
MRA is reviewed. Potential applications of this evolving technique are
illustrated.
PMID- 9766036
TI - Contrast-enhanced magnetic resonance angiography. Potential applications and
pitfalls in magnetic resonance angiography-guided therapy: a review.
PMID- 9766037
TI - Optimizing three-dimensional gadolinium-enhanced magnetic resonance angiography.
Original investigation.
AB - RATIONALE AND OBJECTIVES: This primarily theoretical work examines three
dimensional gadolinium-enhanced magnetic resonance angiography f8p4Gd-MRA) with
the goal of understanding how to achieve the best possible images with respect to
signal to noise ratio (SNR) and k-space induced artifacts. Patient variables,
contrast injection schemes, and pulse sequence parameters are considered for this
purpose. METHODS: A theoretical analysis, including computer simulation,
describes how contrast material injection profiles influence 3D Gd-MRA images,
both in terms of intravascular signal and resultant artifacts. Further
theoretical analysis of the spoiled gradient refocused pulse sequence describes
how to maximize SNR. Clinical imaging complements computer modeling. RESULTS:
Equations were derived relating contrast injection parameters and pulse sequence
variables to SNR and artifacts. For present imaging equipment, administering
contrast material over a duration of 60% to 80% of the total imaging time and
using fractional echo techniques gives the best SNR without significantly
sacrificing image quality. CONCLUSIONS: Three-dimensional Gd-MRA can be tailored
to a specific clinical situation and imaging system through the use of proper
breath-holding, bolus timing, Gd administration, and pulse sequence design.
PMID- 9766038
TI - Contrast-enhanced magnetic resonance angiography of peripheral vessels. Different
contrast agent applications and sequence strategies: a review.
AB - In this article the relation between contrast medium (CM) application and
sequence parameters will be discussed with respect to clinical use of the
contrast-enhanced magnetic resonance angiography (CE-MRA) in the peripheral
vessel region. The adjustment of the sequence parameters, the CM application
timing and the bolus geometry is necessary for an effective use of CE-MRA.
Investigation protocols for several vascular regions differ mainly corresponding
to varying fields of view and slab thickness. Restrictions of increasing the
measurement time are expected in peripherally localized vessels if fast
arteriovenous transit time occurs. The vessel contrast depends from (1) optimal
CM bolus timing and (2) bolus geometry defined by the parameters of the
intravenous bolus injection (flow rate, dose and NaCl flush volume). Our study
results have shown that the bolus remains compact but also shorter if a higher
flow rate is being applied at equal dose. The enlargement of the NaCl flush
volume has evidently caused an increased intraarterial CM concentration and a
slightly bolus lengthening. The exact timing regimen requires an automated
mechanical CM injection pump. In most countries, a total dose of 0.3 mmol/kg Gd
is allowed for application during one investigation. Therefore, obtaining an
angiogram of the entire iliac and leg region this total dose must be separated.
0.1 mmol/kg for each of the three measurements can be recommended. Otherwise,
using this lower CM dose results in less spatial resolution. At least a dosage of
0.2 mmol/kg Gd is necessary to achieve a higher spatial resolution. The
calculation of CM dosage should be also related to the dedicated vessel region of
interest than to the body weight only.
PMID- 9766039
TI - Technology assessment of magnetic resonance angiography. Why pretty pictures are
not enough: an overview.
PMID- 9766040
TI - Patient preference for magnetic resonance versus conventional angiography.
Assessment methods and implications for cost-effectiveness analysis: an overview.
PMID- 9766041
TI - Contrast-enhanced magnetic resonance angiography of cerebral arteries. A review.
AB - The loss of blood vessel visibility due to the signal saturation of slow flow can
be partially overcome by the T1 reduction that occurs with the use of contrast
agents such as Gd-DTPA during magnetic resonance angiography (MRA) studies.
Dynamic-imaging techniques that have been applied successfully in abdominal
imaging may also be useful for intracranial applications. However, the time
between arterial and venous enhancement is very short during intracranial
circulation. This limits the spatial resolution that can be obtained between
arterial and venous enhancement. Fortunately, the blood-brain barrier and the
relatively long duration of significant decrease in blood T1 has led to the
development of very high resolution intracranial MRA techniques. Knowledge of the
contrast-agent dilution factors and the ultimate resulting relaxation rates can
be used to optimize the imaging parameters to maximize vessel signal relative to
the background signal (the signal-difference-to-noise ratio). The additional
venous vascular detail in the contrast-enhanced study can be spatially resolved
in the 3D image data and determined by incorporating information from both high
resolution precontrast and postcontrast studies. In this article, the history,
development and application of contrast agents in MRA are presented.
PMID- 9766042
TI - Contrast-enhanced magnetic resonance angiography of the cervical arteries. A
review.
PMID- 9766043
TI - Contrast-enhanced magnetic resonance imaging of the coronary arteries. A review.
AB - The advent and continued improvement of T1-shortening contrast media have
revolutionized magnetic resonance angiography (MRA) of the entire body in recent
years. The technical basis for contrast-enhanced MRA is fast three-dimensional
(3D) imaging. A brief historic review of the technical advances in MR coronary
artery imaging clearly points to the importance of improved gradient capabilities
that led to the development and wide application of fast 3D imaging. The use of
contrast agents in coronary artery imaging has been expected for many years,
given its success in other parts of the body. Nevertheless, because of the
potential difficulties and unique characteristics of fast 3D imaging in the
heart, the utility of contrast agents in coronary artery imaging has been
systematically investigated only in the last 2 years. Initial experience from our
group and others showed that contrast agents have great potential in pushing MR
coronary artery imaging to a much higher level in terms of speed and signal-to
noise ratio (SNR), and intravascular agents are more desirable than extracellular
agents. Nevertheless, because of the technical challenges and the diversity of
methods used for coronary artery imaging, much more effort is needed to continue
to improve the imaging techniques and further to define the roles of contrast
agents in coronary artery imaging.
PMID- 9766044
TI - Gadolinium-enhanced three-dimensional magnetic resonance angiography of the
thoracic aorta and arch vessels. A review.
PMID- 9766045
TI - Contrast-enhanced magnetic resonance angiography of the pulmonary vasculature. A
review.
AB - Magnetic resonance angiography (MRA) has been established as a powerful
noninvasive imaging modality. Its applications to the study of the pulmonary
vasculature have been hampered by a multitude of factors, such as respiratory and
cardiac motion artifacts, saturation problems, long acquisition times, and
limited spatial resolution. The recent introduction of contrast-enhanced MRA (CE
MRA) has greatly improved the potential for possible investigation of the
pulmonary arteries under clinical conditions. Three-dimensional sequences with
minimum TR and TE, a flip angle between 20 degrees and 60 degrees, and minimum
slice thickness can be considered an optimal approach for breath-hold imaging
combined with the automatic injection of contrast medium. Early studies have
demonstrated the superiority of CE-MRA over nonenhanced techniques. The major
indication for CE-MRA of the pulmonary vasculature is pulmonary embolism. Here a
sensitivity of 85% and specificity of 95% can be obtained. It can be complemented
by perfusion imaging, ventilation imaging, functional measurements of the right
ventricle, and MR venography of the pelvic and femoral veins. Blood pool contrast
agents will open new perspectives in the future. This article reviews the
technical aspects of CE-MRA of the pulmonary vasculature, pathologic findings,
and their interpretation as well as present and future clinical applications.
PMID- 9766046
TI - Gadolinium-enhanced magnetic resonance angiography of the aorta. A review.
PMID- 9766047
TI - Portal venous magnetic resonance angiography. A review.
PMID- 9766048
TI - Differences in predominant enhancement mechanisms of superparamagnetic iron oxide
and ultrasmall superparamagnetic iron oxide for contrast-enhanced portal magnetic
resonance angiography. Preliminary results of an animal study original
investigation.
AB - RATIONALE AND OBJECTIVES: To determine the effect of particle size of
superparamagnetic iron oxide (SPIO) contrast agents on magnetic resonance
angiography of the portal venous system. METHODS: We studied eight beagle dogs by
a T1-weighted 3D turbo-gradient echo magnetic resonance (MR) angiography sequence
(TE 4 milliseconds, TR 11 milliseconds, flip angle 25 degrees, coronal imaging
plane) before and after administration of either Resovist (SHU555A), a
superparamagnetic iron oxide contrast agent with a mean particle size of 60 nm
and a relaxivity ratio R2/R1 of approximately 7, or a new ultrasmall
superparamagnetic iron oxide (USPIO) contrast agent with a mean particle size of
approximately 20 nm and a R2/R1 ratio of approximately 2. Images were acquired on
a 1.5-T MR body scanner. Both agents were injected as a peripheral bolus of 40
mumol Fe/kg body weight. Repeated scans were acquired before, immediately after,
and 10, 20, 30, and 40 minutes after administration of the agent. RESULTS: After
administration of Resovist, portal venous signal increased to 237% of control
immediately after injection, while hepatic parenchymal signal intensity decreased
to 86% of control. The maximal CNR increase to 177% was achieved immediately
after injection of the agent. After USPIO, portal venous signal increased to 401%
of the precontrast value immediately after injection, while hepatic parenchymal
signal intensity also increased to 131% of control at this time. Hepatic signal
then decreased progressively to 49% of control after 40 minutes. The maximal CNR
increase to 326% was achieved 10 minutes after injection of the agent.
CONCLUSIONS: It is concluded that superparamagnetic iron oxide particles of
different sizes have different R2/R1 ratios and, consequently, different
mechanisms of contrast improvement in T1-weighted portal MR angiograms.
PMID- 9766050
TI - Contrast-enhanced magnetic resonance angiography of the renal arteries. Original
investigation.
AB - RATIONALE AND OBJECTIVES: The authors determine the value of contrast-enhanced,
three-dimensional (3D) magnetic resonance angiography (MRA) in the assessment of
the renal arteries in comparison with conventional arteriography (CA). METHODS:
One hundred three patients (71 m, 32 f) were evaluated with both CA and 3D MRA.
The 3D MRA data set consisted of 44 contiguous sections, acquired in apnea (23-28
seconds) using the following parameters: TR/TE 3.9/1.5 milliseconds, flip angle
40 degrees to 50 degrees, 3/4 k-space acquisition. A bolus of 0.3 mmol/kg BW
gadolinium-DTPA was administered intravenously, using an automated injector. A
test bolus method was used for timing of the bolus relative to the beginning of
the data acquisition. Intra-arterial CA was used as the standard of reference in
all patients. Separate interpretations of the CA and MRA results were made by two
different pairs of radiologists, who were each blinded to the results of the
other exam. RESULTS: In all, 31 of 33 accessory renal arteries were correctly
identified. All 205 main renal arteries were seen with MRA. Of 65 significant
stenoses identified on CA, 61 were correctly identified and graded by MRA.
Sensitivity and specificity values for the assessment of significant renal
arterial lesions were 93% and 90%, respectively. CONCLUSIONS: Breath-hold,
contrast-enhanced 3D MRA allows for the reliable assessment of renal arterial
morphology and pathologic states.
PMID- 9766049
TI - Gadolinium-enhanced magnetic resonance venography of the portal venous system
prior to transjugular intrahepatic portosystemic shunts and liver
transplantation. Original investigation.
AB - RATIONALE AND OBJECTIVES: The accuracy of gadolinium-enhanced magnetic resonance
venography (GdMRV) in identifying visceral venous abnormalities was assessed in
patients before they underwent transjugular intrahepatic portosystemic shunt
(TIPS) or orthotopic liver transplantation (OLT). METHODS: Twenty-seven patients
with portal hypertension underwent GdMRV and transcatheter venography prior to
OLT or TIPS. The gadolinium dose was 0.5 mL/kg (0.25 mmol/kg), administered by
rapid hand injection. Coronal 3D spoiled gradient-echo GdMRV was performed in a
single breath-hold. Four blinded reviewers retrospectively evaluated coronal
maximum intensity projection (MIP) images, while two reviewers evaluated the MIPs
and multiplanar reconstructions. Abnormalities that could affect transjugular
intrahepatic portosystemic shunt or transplantation were noted and compared with
the results of corresponding catheter venograms read by a separate blinded
reviewer. RESULTS: Abnormalities were identified by GdMRV with a sensitivity and
specificity of 83% and 97% for the right hepatic vein, 86% and 100% for the main
portal vein (MPV), 42% and 99% for the right portal vein, 54% and 94% for the
left portal vein, 61% and 96% for the superior mesenteric vein, and 74% and 91%
for the splenic vein. Varices and shunts were correctly identified with a
sensitivity of 96%. Multiplanar reconstruction increased MPV sensitivity to 100%.
CONCLUSION: Vascular abnormalities that affect TIPS and OLT can be identified by
GdMRV. Multiplanar reconstruction increased the accuracy to 100% for the MPV.
PMID- 9766051
TI - Renal anatomic changes on magnetic resonance imaging and gadolinium-enhanced
magnetic resonance angiography after renal revascularization. Original
investigation.
AB - RATIONALE AND OBJECTIVES: The anatomic and hemodynamic renal changes after renal
arterial revascularization (RAR) were investigated. METHODS: Thirty-seven kidneys
and 40 renal arteries were evaluated in 20 patients by using magnetic resonance
imaging/magnetic resonance angiography (MRI/MRA) to assess pre- and post-RAR
renal length and mass, parenchymal thickness, renal enhancement, renal artery
caliber, poststenotic dilation, and signal dephasing on 3D phase contrast (PC).
The kidneys and renal arteries were segregated into three groups. Group 1
included 16 patients who benefited from RAR (defined as clinical improvement
based on decreased serum creatinine or fewer number of antihypertensive
medications) in whom 26 renal arteries in 25 kidneys were studied. Intervention
included renal artery endarterectomy (n = 20); aortorenal bypass (n = 3); renal
artery reimplantation (n = 3); and percutaneous transluminal angioplasty (PTA; n
= 1). A total of 27 interventions was performed, as PTA failed for one patient
who subsequently underwent aortorenal bypass before reimaging. Group 2 included
four patients who did not clinically benefit. A total of eight revascularized
arteries were studied in seven kidneys. In group 3, six renal arteries in five
kidneys from groups 1 and 2 without RAS/RAR were analyzed as an internal control.
RESULTS: Technical success (defined as increased vessel caliber after
intervention) was achieved in 33 of the 34 revascularized arteries. A
statistically significant increase in renal length occurred regardless of
clinical outcome (pre-RAR, 9.5 cm; post-RAR, 10.5 cm; P < 0.0001). Parenchymal
thickness and renal mass, however, improved only in patients who benefited
clinically from RAR. Parenchymal enhancement was unchanged in any of the groups
studied. No significant morphologic changes were detected in the control group.
CONCLUSIONS: Magnetic resonance imaging and Gd-MRA detect anatomic and
hemodynamic changes that occur with renal revascularization.
PMID- 9766053
TI - Contrast-enhanced three-dimensional magnetic resonance angiography of the
splanchnic vasculature before and after caloric stimulation. Original
investigation.
AB - RATIONALE AND OBJECTIVES: To develop a comprehensive noninvasive magnetic
resonance angiography (MRA) strategy for the morphologic and functional
assessment of the splanchnic arteries, based on a combination of breath-held
contrast-enhanced 3D MRA and segmented k-space 2D phase-contrast acquisitions
acquired before and after caloric stimulation. METHODS: Ten healthy volunteers
were examined twice: once in the fasting state (6 hours with no food intake) and
a second time following caloric stimulation with a standard 475-kcal meal. Flow
in the superior mesenteric artery (SMA) and vein (SMV) was quantitated using a 2D
breath-held, segmented k-space phase-contrast (PC) acquisition in a plane
perpendicular to the axis of the vessels, while vascular morphology was displayed
with a contrast-enhanced 3D MRA acquisition consisting of 44 contiguous 2-mm
sections, acquired in apnea (28 seconds). For comparative analysis, the
splanchnic vasculature was divided into 11 segments and evaluated on a 2-point
scale (cannot exclude pathology, can exclude pathology). RESULTS: Flow volume in
the SMA increased from 2.3 ml/min/kg (+/- 0.9 ml/min kg) to 7.3 ml/min kg (+/-
4.7 ml/min kg) following caloric stimulation (P < 0.05). Flow in the SMV exceeded
flow in the SMA and increased from 3.4 ml/min/kg (+/- 0.3 ml/min kg) to 9.1
ml/min/kg (+/- 4.8 ml/min/kg) following stimulation. Flow volume of SMV
correlated better with SMA flow after stimulation. Caloric stimulation
significantly improved visualization of the splanchnic arterial vasculature (P <
0.05). Only 5 of 110 evaluated arterial segments (4.5%) remained inadequately
seen to exclude vascular pathology. CONCLUSION: Magnetic resonance imaging offers
a comprehensive assessment of the splanchnic arterial vasculature based on 3D
display of vessel morphology and analysis of flow function. While the most
relevant proximal vessel segments are visible even under fasting conditions,
caloric stimulation enhances visualization of small vessels.
PMID- 9766052
TI - Magnetic resonance angiography of mesenteric arteries. A review.
AB - There has been continued development of MRI techniques for evaluating mesenteric
vascular disease. Contrast-enhanced magnetic resonance angiography (MRA) can
provide reproducible high resolution, high contrast images of the arterial and
venous mesenteric vasculature and may allow detection of segmental ischemia by
detection of segmental delayed mesenteric or bowel wall enhancement. Cine phase
contrast MRA can provide additional information about the rate and volume of flow
within the major mesenteric arteries and veins. Real-time MRI can provide
interactive visualization of the mesenteric vessels in any plane, and with
suitable bowel contrast, it can be used to monitor global and segmental small
bowel motility. With in vivo MR oximetry, flow independent measurements of the T2
relaxation of blood allow the oxygen saturation of the mesenteric circulation to
be determined. These MR techniques can be combined for evaluating both anatomic
and functional aspects of the mesenteric circulation.
PMID- 9766054
TI - Magnetic resonance angiography of the hand. A review.
PMID- 9766055
TI - Magnetic resonance angiography with gadomer-17. An animal study original
investigation.
AB - RATIONALE AND OBJECTIVES: Our purpose was to investigate a "blood pool" contrast
agent for abdominal and thoracic MR angiography by comparison with standard ionic
and nonionic gadolinium-based contrast agents, which redistribute into the
extracellular fluid compartment. METHODS: Abdominal and thoracic MR angiography
was performed in three adult dogs using a three-dimensional spoiled gradient echo
pulse sequence before and after intravenous administration of one of three
gadolinium-based contrast agents (gadopentetate dimeglumine, gadobutrol, and
gadomer-17). Each compound was tested at five different doses in all three dogs.
Quantitative analysis of signal-to-noise ratio (SNR) was performed in the aorta,
inferior vena cava (IVC), liver, spleen, kidney (medulla and cortex), fat, and
muscle. RESULTS: Gadomer-17 improved visualization of vascular anatomy at doses
of 0.025, 0.05, 0.1, and 0.2 mmol/kg with three-fold greater aorta SNR during the
arterial phase and more than four-fold greater aorta and IVC SNR during the
equilibrium phase, in comparison with gadopentetate dimeglumine and gadobutrol at
equal doses. CONCLUSIONS: Gadomer-17 is a promising contrast agent for both
arterial phase and equilibrium phase MR angiography.
PMID- 9766056
TI - The future of contrast-enhanced magnetic resonance angiography. Are blood pool
agents needed?
PMID- 9766057
TI - An improved direct plate method for the enumeration of stressed Escherichia coli
O157:H7 from food.
AB - The use of sorbitol MacConkey agar (SMAC) performed poorly in supporting growth
of stressed Escherichia coli O157:H7 cells. Up to a 3-log difference was observed
between counts on SMAC and tryptone soy agar (TSA). It is critical in the risk
assessment of certain foods to be able to enumerate stressed and healthy E. coli
O157:H7 in a background of potentially healthy competing bacteria. Investigations
carried out to overcome the inhibitory effect of SMAC included the reduction of
the selective agent concentration, inclusion of a recovery stage in broth prior
to plating out, addition of recovery agents, and delayed exposure to the
selective agent. The only successful approach was delayed exposure to the
selective agent. This was achieved by resuscitating the stressed cells on a
membrane placed on the surface of a TSA plate and, after a defined time period
sufficient for full resuscitation, transferring the membrane to the surface of a
SMAC plate. The choice of membrane material was critical for maintaining the
positive sorbitol color change used to identify wild-type E. coli. Track-etched
polycarbonate membranes allowed the typical color reactions to be visualized,
whereas cellulose acetate did not. The method was validated with E. coli O157:H7
cells stressed by low pH and high salt conditions, whereby all cells that would
previously be undetectable on direct inoculation of SMAC were countable.
PMID- 9766058
TI - Effectiveness of salt, pH, and diacetyl as inhibitors for Escherichia coli
O157:H7 in dairy foods stored at refrigeration temperatures.
AB - The behavior of Escherichia coli O157:H7 inoculated in 10% rehydrated nonfat dry
milk adjusted to pH levels between 3.8 and 5.4 with lactic acid, salt levels of 0
to 6%, and diacetyl levels of 0, 5, and 10 micrograms/g was determined at 4 and
12 degrees C. Cell populations were determined by surface plating on tryptic soy
agar after 7 and 35 days of incubation. Survival was also determined using retail
cultured diary products. E. coli O157:H7 did not survive in skim milk at pH 3.8
and was reduced by 3 log cycles at pH 4.1, regardless of salt, diacetyl, and
temperature levels. At pH levels above 4.4, survival was observed at lower salt
concentrations for up to 35 days at both 12 and 4 degrees C. The organism grew
(up to a 2.2-log increase) at pH 5.0 at 2% salt levels after 35 days of storage
at 12 degrees C. Diacetyl at a concentration of 10 ppm had no effect on survival
and growth. In all but one case, E. coli O157:H7 was inactivated in yogurt, sour
cream, and buttermilk at a rate similar to or greater than what was consistent
with the acidified skim milk data. Also consistent with the skim milk data,
growth occurred in two of the three cottage cheese samples at 12 degrees C after
7 days but not after 35 days or at 4 degrees C, when a 1- to 2-log decline was
observed.
PMID- 9766059
TI - Bacterial cross-contamination of meat during liquid nitrogen immersion freezing.
AB - Prerigor beef carcass surface tissue (BCT) was used to simulate lamb carcasses on
a processing line with a 15-min liquid nitrogen (LN) immersion freezing step, and
the potential for the dissemination of bacteria during freezing was examined.
Streptomycin-resistant strains of Listeria innocua and Escherichia coli O157:H7
spiked into a fecal slurry were inoculated onto BCT pieces that were introduced
into the freezing process to represent contaminated carcasses. Following this
introduction, subsequently frozen uninoculated BCT, LN, and LN containers were
examined for the inoculated organisms. In the first study, BCT samples were
inoculated with ca. 7 log CFU/cm2 of both L. innocua and E. coli O157:H7, spray
washed with water and frozen, distributed among uninoculated BCT, in LN for 15
min. In two separate trials, L. innocua was recovered by enrichment from all
uninoculated BCT and LN samples. E. coli O157:H7 was also recovered from
uninoculated BCT and LN, but this cross-contamination was more sporadic. Both
species were recovered from the LN container following freezing. Attempts to
enumerate cross-contaminating bacteria in the second trial indicated that
contaminating levels were low (< 1.0 CFU/cm2 BCT). In a second study, a 2.0%
lactic acid spray wash was used to reduce further the numbers of L. innocua
introduced into the freezing system and resulted in fewer positive samples,
although this organism was still recovered from many uninoculated BCT samples.
When either bacterium was inoculated at lower initial levels (1.35 to 1.77 log
CFU/cm2) and BCT was water or 2.0% lactic acid spray washed prior to freezing,
neither L. innocua nor E. coli O157:H7 was recoverable by enrichment from
uninoculated BCT, LN, or from the freezing container. Results demonstrate that
bacterial cross-contamination of meat during LN immersion freezing can occur but
indicate that the use of good sanitation practices and product with low microbial
numbers can limit this occurrence.
PMID- 9766060
TI - Bacterial profile of ground beef made from carcass tissue experimentally
contaminated with pathogenic and spoilage bacteria before being washed with hot
water, alkaline solution, or organic acid and then stored at 4 or 12 degrees C.
AB - The long-term effectiveness of several beef-carcass surface-tissue (BCT) wash
interventions on the microbiology of ground beef produced from this tissue was
determined. BCT was inoculated with bovine feces containing one of two different
levels (ca. 4 or 6 log CFU/ml) of Escherichia coli O157:H7, Listeria innocua,
Salmonella typhimurium, and Clostridium sporogenes. The BCT was then subjected to
one of several treatment washes: 2% (vol/vol) DL-lactic acid (LA), 2% (vol/vol)
acetic acid (AA), 12% (wt/vol) trisodium phosphate (TSP), hot water (HW; 74 +/- 2
degrees C at the tissue surface), or water (WW; 32 +/- 2 degrees C at the tissue
surface). A control group was left untreated. After treatments, BCT was held at 4
degrees C for 24 h and then ground. The ground beef was packaged and incubated at
4 degrees C for 21 days or 12 degrees C for 3 days. AA-treated samples held at 12
degrees C for 3 days yielded significantly lower aerobic plate counts than the
control and also yielded the lowest levels of pseudomonads when compared to other
sample groups. After being held at 4 degrees C for 21 days or 12 degrees C for 3
days, samples treated with antimicrobial compounds had lower or no detectable (<
1 CFU/g) levels of E. coli O157:H7, L. innocua, S. typhimurium, and C. sporogenes
than beef treated with a WW or the control. Ground beef produced from tissue
treated with HW yielded lower populations of these bacteria when compared to WW
or untreated control beef, but the populations were generally higher than those
observed in any of the antimicrobial chemical-treated samples. These trends
continued throughout all storage conditions over time. Results from this study
indicate that the use of carcass interventions, especially antimicrobial
compounds, presently available to the slaughter industry will lower bacterial
counts in ground beef.
PMID- 9766061
TI - False-positive fluorescence by pink salmon tissue and staphylococci in a rapid
test for Escherichia coli.
AB - Fluorescence from 4-methylumbelliferyl-beta-D-glucuronide (MUG) hydrolysis is a
common, rapid method for determining Escherichia coli in water and food. False
positive fluorescence occurred when either pink salmon fillets were tested or
beta-glucuronidase-positive Staphylococcus species were present in other fish
products. Salmon fillet, E. coli, S. xylosus, and S. warneri produced 2, 17, 39,
and 43 nmol of 4-methylumbelliferone per ml, respectively, in a one-step
detection broth (lauryl salts tryptose broth with MUG) for E. coli after 48 h at
35 degrees C. These false-positive reactions need to be considered when testing
fish products, especially those contaminated through human handling.
PMID- 9766062
TI - Antibacterial effects of N-sulfonated and N-sulfobenzoyl chitosan and application
to oyster preservation.
AB - The antibacterial effects of sulfonated and sulfobenzoyl chitosans were evaluated
and compared with that of 69% deacetylated chitosan (DD69 chitosan). Minimal
inhibitory concentrations of sulfonated chitosan (SC1, 0.63% sulfur content)
against Shigella dysenteriae, Aeromonas hydrophila, Salmonella typhimurium, and
Bacillus cereus were found to be lower than those of DD69 chitosan. A high sulfur
content in sulfonated chitosan adversely influenced its antibacterial effect.
Sulfobenzoyl chitosan (SBC) has excellent water solubility and an antibacterial
effect comparable to that of SC1. SBC at 1,000 and 2,000 ppm extended the shelf
life of oysters at 5 degrees C by 4 days at the former or by 7 days at least at
the latter concentration. The growth of coliforms and Pseudomonas, Aeromonas, and
Vibrio species on oysters was retarded by the addition of DD69 chitosan or SBC.
PMID- 9766063
TI - Thawed cod fillets spoil less rapidly than unfrozen fillets when stored under
modified atmosphere at 2 degrees C.
AB - The effect of two months of frozen storage at -20 degrees C on the spoilage
characteristics and shelf life of thawed and modified atmosphere packed (MAP) cod
fillets stored at 2 degrees C was studied. Thawed MAP cod fillets were compared
with fresh cod fillets stored in CO2-containing modified atmospheres with and
without added oxygen. The shelf life of 11 to 12 days in the fresh MAP cod was
extended to more than 20 days in the thawed MAP cod at 2 degrees C. This shelf
life extension was most likely due to the inactivation of the spoilage bacterium
Photobacterium phosphoreum during frozen storage as reflected both in chemical
analyses and sensory evaluation. In contrast to fresh MAP cod fillets no
significant production of trimethylamine occurred and almost no amine odor and
taste were detected during 20 days of chill storage of thawed MAP cod fillets.
The use of frozen fillets as raw material not only provides a more stable product
in MAP but also allows much greater flexibility for production and distribution.
However, a slightly increased concentration of dimethylamine, a larger drip loss,
and detection of weak frozen storage flavor were observed in the thawed MAP cod
fillets.
PMID- 9766064
TI - Listeria innocua and Salmonella panama in mussels: a comparative study.
AB - Bivalve molluscs are exposed to a wide range of contamination by pathogenic
bacteria and viruses. Therefore, the behavior of bacterial pathogens in bivalves
after harvesting is important in terms of food safety. Mussels were artificially
contaminated with Listeria innocua and Salmonella panama, held under different
conditions, and then examined for Listeria and Salmonella viable counts. In a
simplified depuration system, L. innocua levels were lower than those observed
for S. panama in mussels during the same period and under the same conditions.
This result may be related to the rapid die-off reported for Listeria in
seawater. In mussels stored in air, the two pathogens presented similar
behaviors: levels of both pathogens remained constant in mussels during the
storage period in air. However, in shucked mussels Listeria innocua counts
increased with the duration of storage, whereas Salmonella panama showed a slight
decrease.
PMID- 9766065
TI - Alteration in sporulation, enterotoxin production, and protein synthesis by
Clostridium perfringens type A following heat shock.
AB - Application of a heat shock (43 to 50 degrees C) applied early during the
sporulation process of Clostridium perfringens delayed spore and enterotoxin
production. Final levels of heat-resistant spores were similar to the control,
but enterotoxin levels were reduced when the heat shock was applied at the third
hour of incubation. The response of the microorganism to the heat shock was also
examined by analysis of pulse-labeled proteins. Seven heat shock proteins (HSPs)
associated with vegetative cells were identified by polyacrylamide gel
electrophoresis. Most were localized mainly in the membrane, although one small
protein was mostly present in the cytoplasm. Fewer HSPs were detected during
sporulation. Two HSPs were immunologically related to the GroEL and DnaK HSPs
from Lactobacillus lactis and Escherichia coli, respectively.
PMID- 9766066
TI - Microbiological quality and the inability of proteolytic Clostridium botulinum to
produce toxin in film-packaged fresh-cut cabbage and lettuce.
AB - The production of toxin by a 10-strain mixture of proteolytic Clostridium
botulinum in fresh produce packaged in polyethylene films having high (7,000
cc/m2/24 h; HOTR) and low (3,000 cc/m2/24 h; LOTR) relative oxygen permeability
was determined. Shredded cabbage and lettuce inoculated with approximately 10(2)
spores/g were placed in bags composed of the two films (1.4 kg/bag), and the bags
were then vacuum sealed. Produce was stored at 4, 13, and 21 degrees C for up to
21 (cabbage) or 28 (lettuce) days and analyzed periodically. At each sampling
time, the gas composition within the bags, pH of the produce, and microbial
populations (total aerobic and anaerobic microorganisms, lactic acid bacteria,
psychrotrophic bacteria, and yeasts and molds) were determined. In addition, the
presence of botulinal toxin was determined using the standard U.S. Food and Drug
Administration mouse bioassay protocol. Bags made of HOTR film prolonged sensory
quality of cabbage and lettuce, especially at 13 and 4 degrees C. Packaging
material had an effect on the growth of various groups of microorganisms;
however, there was not a general trend. For example, lettuce packaged in HOTR
bags had higher aerobic microbial populations than that packed in LOTR, but no
significant difference (P < or = 0.05) was observed with cabbage. Growth of
psychrotrophic bacteria was greater in vegetables packaged in HOTR film while
growth of yeasts and molds was not affected by either packaging film. Most
differences in microbial populations in produce packaged in LOTR and HOTR films
were less than 1 log10 CFU/g. Botulinal toxin was not detected in cabbage or
lettuce packaged in either film or stored under any test condition.
PMID- 9766067
TI - Conservative prediction of time to Clostridium botulinum toxin formation for use
with time-temperature indicators to ensure the safety of foods.
AB - Integrating-type time-temperature indicators (TTIs) may be utilized to warn food
processors and consumers about storage conditions that may have rendered a food
potentially hazardous. As an example of how integrated TTIs could be manufactured
to emulate an infinite set of time-temperature situations, a set of conditions
which have supported C. botulinum growth and toxin production was compiled. The
time-temperature curve representing conservative times required for toxin
formation was constructed with data from literature relating to toxin formation
as a function of temperature in any media or food product. This set of critical
time-temperature data is fit by a conservative empirical relationship that can be
used to predict combinations of incubation times and storage temperatures that
represent a potential health risk from C. botulinum in foods. A TTI could be
constructed to indicate deviation from such a given set of conditions to bring
attention to foods that may have been exposed to potentially hazardous
temperatures with respect to C. botulinum toxin formation.
PMID- 9766068
TI - Quality of commercial shelf-stable soymilk products.
AB - Four brands of shelf-stable soymilks (three lots each) were evaluated for their
quality. All samples were tested for trypsin inhibitor activity, microbial load
(coliforms, aerobic mesophiles, and psychrotrophs), solids content, pH, color,
and viscosity. Storage stability at 5 degrees C of the opened original containers
was evaluated by microbiological analyses. Physical properties were consistent
among three lots of the same brand, but varied among brands. Trypsin inhibitor
activity ranged from 3.43 to 10.35 mg/g dried soymilk. The pH values of the
soymilks varied between 6.41 and 7.34. Viscosity was measured between 16.5 and
26.4 mPa. Solids content varied considerably among soymilks, from 6.88 to 12.37%
(wt/vol). Freshly opened commercial soymilk contained fewer than one
microorganism per ml in all microbial counts. During storage at 5 degrees C,
microbial counts increased sharply after 2 to 3 weeks. A single microorganism
predominated in each stored sample. Shelf life (defined as the time during which
aerobic mesophile counts remained below 10(6) CFU/ml) varied from 3 to 4 weeks.
The appearance and pH of soymilks remained unchanged even after 4 weeks of
storage. Five types of microorganisms were found in stored soymilk samples; none
of them produced acid.
PMID- 9766069
TI - A nondestructive leak detection method for flexible food packages using hydrogen
as a tracer gas.
AB - A nondestructive leak detection method developed at Technical Research Centre of
Finland (VTT) was tested for both gas-flushed and vacuum flexible packages. In
the method, a gas package containing 0.5 to 5.0% (vol/vol) hydrogen in nitrogen
was positioned in a test chamber, a controlled vacuum was pulled in the chamber
through a pipe connected to a hydrogen sensor, and leaking packages were detected
by the sensor as increased H2 concentration. The H2 tracer gas (0.5 to 5.0%) was
introduced into leaking finished vacuum packages at 200 kPa pressure. Within 1 to
4 s the developed test method was able to detect leaks down to 10 to 15 microns
and 20 to 30 microns in diameter in commercially manufactured gas-flushed
packages filled with roasted meat balls and vacuum packages filled with ground
coffee, respectively. Before leak testing, the vacuum packages were charged with
H2 for 30 s. The sensitivity and leak detection time of the test method were
improved when the H2 concentration in the package was increased and when the free
space in the test chamber was decreased. The evaluated H2 concentrations did not
affect the sensory or microbiological quality of the roasted meat balls. This
study clearly demonstrated that the hydrogen tracer gas leak detection method has
potential to be further developed as a fast, nondestructive, on-line leak testing
apparatus for flexible packages with or without a headspace.
PMID- 9766070
TI - An evaluation of the collection and analysis of epidemiological data for support
of food safety control systems.
AB - Food-borne disease data collected by three U. K. environmental health departments
were used in this study. The data were analyzed using a database designed to rank
disease agents, food ingredients, and processing factors which contribute to
cases of food-borne disease. The results established changes in patterns of food
borne disease over time, pattern differences between U. K. localities and
differences between areas of the United Kingdom and the United States. This type
of analysis of epidemiological data provides scientific underpinning for hazard
analysis critical control point systems for food safety control. The work
highlights the need for a consistent procedure for collection of food-borne
disease data and for a national database to facilitate analysis.
PMID- 9766071
TI - College students' attitudes, practices, and knowledge of food safety.
AB - A survey instrument was developed to assess attitudes, practices, and knowledge
of food safety of college students in three U.S. geographic locations. Eight
hundred twenty-four students in both food-related (one-third of sample) and
nonfood-related disciplines completed the questionnaire during classroom periods.
Data were analyzed to obtain total attitude, practice, and safety scores, with
emphasis given to analyzing differences among disciplines and demographic
characteristics. Mean scores were given for each of the survey items, and results
from open-ended questions were discussed. Dietetic, food science, nutrition, and
health majors had significantly (< or = 0.05) higher attitude scores than
students majoring in other disciplines. No differences were found among
disciplines for the practice scores, which ranged from 74 to 79% of the total
possible practice score. Students enrolled in dietetics, arts and science
(physical sciences), and veterinary medicine had significantly (< or = 0.05)
higher knowledge scores, although the highest mean score (for dietetics) was only
74% of the total possible score. Women who had enrolled in a college course that
included food safety information had significantly (< or = 0.05) higher attitude
and practice scores. Such course enrollment led to both genders having
significantly (< or = 0.05) higher knowledge scores than those without this
opportunity. Implications were given for using these data to encourage college
professors in food-related disciplines to become involved with the education of
all future consumers, especially as the prevalence of food safety controversies
is likely to increase as the food supply changes and technology becomes more
sophisticated.
PMID- 9766072
TI - Survival of Escherichia coli O157:H7 after freezing and thawing in ground beef
patties.
AB - Survival of Escherichia coli O157:H7 strains QA 326, and ATCC 43889, 43894, and
43895 after freezing (-20 degrees C, 24 h) and thawing (4 degrees C for 12 h, 23
degrees C for 3 h, or microwave heating of 700 W for 120 s) in ground beef
patties was determined by reference most probable number (MPN), hydrophobic grid
membrane filter SD-39 agar, and sorbitol MacConkey agar (SMA) spread-plating
methods. Populations decreased from 0.62 to 2.52 log10 CFU/g, with the extent
varying significantly by strain. Strain QA 326 populations almost always
decreased the most, up to 1.87 log10 CFU/g more than the least sensitive strain.
Microwave heating was the most lethal thawing treatment for strain QA 326, and 4
degrees C thawing was the most lethal treatment for strain ATCC 43894. Thawing
treatments varied in relative lethality for the other two strains. For strain QA
326 (4 degrees C and microwave thaw treatments) and strain ATCC 43889 (4 and 23
degrees C thawing), the enumeration method significantly affected a population
decrease. The SD-39 agar method best recovered strain QA 326 while the SD-39 agar
method and the reference MPN method best recovered strain ATCC 43889 after 4 and
23 degrees C thawing, respectively. The greatest difference in population
decrease measured by any two methods was 0.58 log10 CFU/g. Results showed (i) a
wide range in freeze-thaw sensitivity among E. coli O157:H7 strains, (ii) no
thawing method had consistently and significantly greater lethality, and (iii)
the reference MPN, SD-39 agar, and SMA methods differed little in ability to
enumerate E. coli O157:H7.
PMID- 9766073
TI - Thermotolerance of Escherichia coli O157:H7 ATCC 43,894, Escherichia coli B, and
an rpoS-deficient mutant of Escherichia coli O157:H7 ATCC 43,895 following
exposure to 1.5% acetic acid.
AB - On a beef carcass, Escherichia coli may sequentially encounter acid- and heat
intervention steps. This study tested whether acid stress (1.5% [vol/vol] acetic
acid, pH 4.0, 37 degrees C, 15 min) would enhance subsequent heat resistance of
E. coli. Initially, cells (E. coli O157:H7 ATCC 43894, nonpathogenic E. coli B
[strain FRIK-124], and rpoS-deficient mutant 813-6 [derived from E. coli O157:H7
ATCC 43895]) were acid stressed and transferred to 54 degrees C trypticase soy
broth (TSB), and survivors were immediately enumerated after at least three
intervals of 12, 2, and 6 min, respectively, by plating. The ATCC 43894 and 813-6
strains survived the acid stress but strain FRIK-124 did not. Acid-stressed ATCC
43894 had significantly lower D values than the non-acid-stressed controls.
Strain 813-6 had significantly lower D values than strain ATCC 43894, with no
significant difference between acid-stressed and non-acid-stressed cells. In a
second experiment, cooling of cells prior to plating resulted in an increased D
value for acid-stressed ATCC 43894 cells, such that it was not significantly
different from the D value for non-acid-stressed controls. Using this protocol,
there was no significant difference in D values between acid-stressed and non
acid-stressed ATCC 43894 cells in prewarmed TSB (54, 58, and 62 degrees C), in
prewarmed ground beef slurry (GBS; 58 degrees C), or in TSB and GBS inoculated at
5 degrees C and heated to 58 degrees C. The acid stress tested does not enhance
subsequent heat resistance of E. coli.
PMID- 9766074
TI - Polymacron enzyme immunoassay system for detection of naturally contaminating
Salmonella in foods, feeds, and environmental samples.
AB - A simple dot blot enzyme immunoassay was developed to screen enrichment broth
cultures for the presence of Salmonella. This unique system utilizes macroporous
polyester cloth (Polymacron) with an inexpensive hemoglobin coating to provide a
high-affinity adsorbent for lipopolysaccharide (LPS) antigens in test samples.
Bound LPS antigens are then detected using a monoclonal antibody conjugate
recognizing a core oligosaccharide epitope common to all salmonellae frequently
found in foods and related samples. The entire test (not including enrichment
culture) could be completed in less than 1 h. The performance of this assay was
evaluated in the analysis of enrichment broth cultures from a variety of egg and
dairy products, chicken carcasses, animal feeds, and food-processing plant
environmental samples for the presence of Salmonella.
PMID- 9766075
TI - Specific inhibition of Photobacterium phosphoreum extends the shelf life of
modified-atmosphere-packed cod fillets.
AB - Inhibition of the specific spoilage organism, Photobacterium phosphoreum, was
studied in model substrates and in modified-atmosphere-packed cod fillets. The
objective was to determine how inhibition of this organism influenced spoilage.
The spoilage reactions limiting shelf life were studied rather than the
development of a new product. In naturally contaminated modified-atmosphere
packed cod fillets, 500 ppm Na2CaEDTA reduced the growth rate of P. phosphoreum
by 40% and shelf life was increased proportionally by 40%, from 15 to 17 days to
21 to 23 days at 0 degree C. In aerobically stored cod fillets other
microorganisms were responsible for spoilage and Na2CaEDTA had no effect on shelf
life. The extension of the shelf life of modified-atmosphere-packed cod therefore
was a result of the reduced growth of P. phosphoreum and no other microbial or
nonmicrobial spoilage reactions limited shelf life. These results confirmed P.
phosphoreum as the specific spoilage organism in modified-atmosphere-packed cod
and showed the organism to have an extensive spoilage domain. Consequently, any
preservation procedure able to reduce growth of P. phosphoreum is likely to
extend shelf life of packed cod. However, the effect of different inhibitory
compounds in model systems as well as results from packed cod indicated the need
to include product studies in the screening of antimicrobials and in the
development of preservation procedures.
PMID- 9766076
TI - Reactivities of genus-specific monoclonal antibody EM-6E11 against Listeria
species and serotypes of Listeria monocytogenes grown in nonselective and
selective enrichment broth media.
AB - Depending on the growth medium used for enrichment of bacterial cells prior to
assay, the monoclonal antibody (MAb) EM-6E11 recognizing Listeria genus-specific
epitope on 43 and 94 to 97 kDa cell-surface antigens (A. K. Bhunia and M. G.
Johnson, Appl. Environ. Microbiol. 58:1924-1929, 1992) exhibited extensive
variability in the detection of Listeria species. MAb EM-6E11 strongly detected
live cells of all Listeria species and all serotypes of L. monocytogenes by ELISA
when cells were grown in nonselective brain heart infusion (BHI) broth, in
selective Listeria enrichment broth (LEB), or in Listeria repair broth (LRB). In
contrast, EM-6E11 detected only four of the thirteen serotypes of L.
monocytogenes (serotypes 1/2c, 3b, 4ab, and 7) when cells were grown in the UVM1
formulation of Listeria enrichment broth (UVM1) or Fraser broth (FRB). This MAb
failed to react with live cells of four other Listeria species, including L.
ivanovii, L. welshimeri, L. grayi, and L. murrayi cells grown in UVM1 or FRB.
Heating of Listeria cells at 100 degrees C for 20 min, irrespective of the
enrichment media used, led to large losses of MAb EM-6E11 reactivity in ELISA,
suggesting that the specific cell-surface epitopes involved may not be heat
stable. Our results confirm that MAb EM-6E11 is suitable for detection of live
cells but not heat-killed cells of Listeria spp. and can be used in conjunction
with an enrichment step in BHI, LEB, or LRB but not in UVM1 or FRB.
PMID- 9766077
TI - Identification of Listeria monocytogenes from unpasteurized apple juice using
rapid test kits.
AB - A microbiological survey of 50 retail juices was conducted in the fall of 1996.
These juices were analyzed for Listeria monocytogenes, Escherichia coli O157:H7,
Salmonella, coliforms, fecal coliforms, and pH. Two unpasteurized juices were
positive for L. monocytogenes: an apple juice and an apple raspberry blend with a
pH of 3.78 and 3.75, respectively. Three L. monocytogenes isolates were
characterized. The colonies were typical for Listeria sp. on Oxford and lithium
chloride-phenylethanol-moxalactam agars and were beta-hemolytic on sheep blood
agar. The isolates required 5 days of incubation at 35 degrees C to produce a
positive rhamnose reaction in a phenol red carbohydrate broth. This slow rhamnose
utilization resulted in these isolates not being identified using the Micro-ID
test strip (Organon Technika). However, the isolates were positive for L.
monocytogenes using the API Listeria strip (BioMerieux) and a multiplex
polymerase chain reaction for detection of the hemolysis (hyla) and invasion
associated protein (iap) genes.
PMID- 9766078
TI - Inactivation of Listeria monocytogenes in milk by pulsed electric field.
AB - Pasteurized whole, 2%, and skim milk were inoculated with Listeria monocytogenes
Scott A and treated with high-voltage pulsed electric field (PEF). The effects of
milk composition (fat content) and PEF parameters (electric field strength,
treatment time, and treatment temperature) on the inactivation of the bacterium
were studied. No significant differences were observed in the inactivation of L.
monocytogenes Scott A in three types of milk by PEF treatment. With treatment at
25 degrees C, 1- to 3-log reductions of L. monocytogenes were observed. PEF
lethal effect was a function of field strength and treatment time. Higher field
strength or longer treatment time resulted in a greater reduction of viable
cells. A 4-log reduction of the bacterium was obtained by increasing the
treatment temperature to 50 degrees C. Results indicate that the use of a high
voltage PEF is a promising technology for inactivation of foodborne pathogens.
PMID- 9766079
TI - Occurrence of Erysipelothrix spp. in chicken meat parts from a processing plant.
AB - From March 1996 to March 1997, 153 domestic raw chicken meat samples, including
71 thigh, 50 outer breast muscle, and 32 white meat samples, from a processing
plant located in a chicken abattoir in Nagano Prefecture, Japan, were examined
for the presence of Erysipelothrix spp. Erysipelothrix spp. were isolated from 49
(30.0%) of the 153 chicken meat samples. Of 67 Erysipelothrix isolates, 65 and 2
isolates were identified as E rhusiopathiae and E. tonsillarum. E. rhusiopathiae
and E. tonsillarum isolates were serotyped into 11 and 2 different serovars,
respectively. These findings might indicate that domestic chicken meat is
frequently contaminated with E. rhusiopathiae and seems to be a potential source
of human Erysipelothrix infection.
PMID- 9766081
TI - Oscillatory high hydrostatic pressure inactivation of Zygosaccharomyces bailii.
AB - Zygosaccharomyces bailii inactivation was evaluated in oscillatory high
hydrostatic pressure (HHP) treatments at sublethal pressures (207, 241, or 276
MPa) and compared with continuous HHP treatments in laboratory model systems with
a water activity (aw) of 0.98 and pH 3.5. The yeast was inoculated into
laboratory model systems and subjected to HHP in sterile bags. Two HHP treatments
were conducted: continuous (holding times of 5, 10, 15, 20, 30, 60, or 90 min)
and oscillatory (two, three, or four cycles with holding times of 5 min and two
cycles with holding times of 10 min). Oscillatory pressure treatments increased
the effectiveness of HHP processing. For equal holding times, Z. bailii counts
decreased as the number of cycles increased. Holding times of 20 min in HHP
oscillatory treatments at 276 MPa assured inactivation (< 10 CFU/ml) of Z. bailii
initial inoculum. Oscillatory pressurization could be useful to decrease Z.
bailii inactivation time.
PMID- 9766080
TI - Interactions between pairs of bacteriocins from lactic bacteria.
AB - Activity of pairs of crude extracts of lactic acid bacteria (LAB) containing
different bacteriocins (nisin, pediocin AcH, lacticin 481, lactacin F, and
lactacin B) was measured against 10 different indicator strains. Experiments were
carried out both in liquid and on solid media. Both synergisms and antagonisms
were observed. Lacticin 481 produced mainly antagonistic effects whereas pediocin
AcH produced mainly synergistic effects. The use of more than one LAB bacteriocin
as a combination biopreservative might be envisaged.
PMID- 9766082
TI - A general framework illustrating an approach to quantitative microbial food
safety risk assessment.
AB - Hazard analysis critical control point (HACCP), risk assessment, predictive
microbiology, and dose-response modeling have been recognized as important tools
for the assessment and management of health risks posed by food-borne pathogens.
Unfortunately, the biology of both the food chain and food poisoning is complex
and dynamic. Therefore, mathematical modeling of microbial risk from food
production through to consumption and illness is difficult. Nevertheless,
previous authors have made impressive progress in modeling specific pathogen-food
consumer combinations. In this study a framework for a Monte Carlo model of a
generic food system was developed. It links together food ingredients, batch
processing, cross contamination, microbial growth, cooking, recontamination,
consumption, human exposure to pathogens, the dose-response relationship, and the
biologic and economic impact components of such risks. This framework is
presented to illustrate one potential approach to quantitative risk assessment
for microbial food safety. It requires refinement with appropriate distributions
and mathematical relationships before it can be applied to a specific pathogen
food-consumer situation.
PMID- 9766083
TI - Foodborne illness in the elderly.
AB - The elderly (> or = 65 years of age) are more susceptible to morbidity and
mortality from foodborne-induced gastroenteritis than younger individuals.
Several factors contribute to the increased susceptibility to foodborne
infections as well as other infections in elderly populations. These include an
age-associated decrease in humoral and cellular immunity, age-related changes in
the gastrointestinal tract (decreased production of gastric acid and decreased
intestinal motility), malnutrition, lack of exercise, entry into nursing homes,
and excessive use of antibiotics. Data from foodborne outbreaks associated with
nursing homes indicate that the elderly are more likely to die from foodborne
Campylobacter, Clostridium perfringens, Escherichia coli O157:H7, Salmonella, and
Staphylococcus aureus infections than the general population. Infections by
Salmonella species are the most common cause of illness and death in nursing
homes with Salmonella enteritidis as the major cause of both morbidity and
mortality. While it is impossible to turn back the clock, practicing a healthy
life-style with regular exercise, maintaining a balanced diet, receiving regular
health care, paying attention to personal hygiene, and monitoring food
preparation and handling should lead to a reduced incidence of foodborne and
other infections in the elderly.
PMID- 9766084
TI - Arsenic speciation in manufactured seafood products.
AB - The literature on the speciation of arsenic (As) in seafoods was critically
reviewed. Most research has been directed toward fresh seafood products with few
papers dealing with As speciation in manufactured seafoods. Predictions
concerning As species made on the basis of fresh seafood products cannot be
extrapolated to manufactured seafoods. Therefore, due to the numerous species of
As, the scarcity of data concerning their presence in foods, the transformations
each species may undergo during industrial processing and cooking, and the lack
of legislation on permitted As levels in seafood products, As species in
manufactured seafood products need to be determined and quantified.
PMID- 9766085
TI - Hazard analysis and critical control point principles and application guidelines.
Adopted August 14, 1997. National Advisory Committee on Microbiological Criteria
for Foods.
AB - The HACCP Subcommittee of the National Advisory Committee on Microbiological
Criteria for Foods (NACMCF) has prepared a revision of the document "Hazard
Analysis and Critical Control Point System" that was adopted by the Committee in
1992. The Committee retained the previous seven HACCP principles but made their
wording more concise; revised and added definitions such as those for hazard,
verification, and validation; included new sections on prerequisite programs,
education and training, and implementation and maintenance of the HACCP plan;
revised and provided a more detailed explanation of the application of HACCP
principles, especially hazard analysis and verification; and added or revised
Appendices such as new examples of prerequisite programs and an additional
decision tree for identifying critical control points (CCPs).
PMID- 9766086
TI - [Aortoiliac graft infection as a diagnostic and treatment problem].
AB - Aortoiliac graft infection occurs in 2-6% of patients with such prosthesis. This
condition is seldom properly diagnosed by conventional radiographic methods,
leading to high morbidity and mortality. Clinically, the diagnosis of aortic
graft infection is difficult because patients may have a variety of nondescript
clinical complaints. The diagnosis of graft infection when associated with
minimal or absent clinical signs of low-grade infection is uncertain, but is
critically important to avoid frequently catastrophic complications such as
sepsis, gastrointestinal hemorrhage, and suture line disruption. AIM OF THE
STUDY: identification of bacterial flora present in aortoiliac graft infection;
the presentation of my own experience in the detection of aortoiliac graft
infection with special description of isotopic study with WBC labeled 99mTc HM
PAO and estimation of the usefulness of this test in comparison with computed
tomography, ultrasonography, fistulography and angiography; evaluation of the
usefulness of various treatment methods; establishing principles (algorithm) of
diagnostic and therapeutic procedures in the case of the suspicion of aortoiliac
graft infection. As many as 1190 patients with implanted aortoiliac graft in 1986
1996 at the General and Vascular Surgery Clinic in Szczecin were studied (Tab.
2). Thirty-one patients in the study had deep aortoiliac graft infection (Tab.
3), while 9 patients had, in addition, prosthetic-enteric fistulae and 1 had
arterio-enteric secondary fistulae. The group of 31 patients with deep graft
infection, that is 2.6% of all patients (1190), had aortoiliac graft implanted at
the mentioned time period (Tab. 4, 5). Test results for detection of graft
infection have been analysed (Tab. 17). The results of isotopic investigation
(Tab. 16), computed tomography (Tab. 11), ultrasonography (Tab. 13),
fistulography (Tab. 14) and angiography (Tab. 15) were compared with
intraoperative state or in a case of exclusion of infection, with results of
follow up. Results of various paths of treatment were estimated (Tab. 18). Based
on performed cultures most common bacterial flora from infected grafts, was
identified (Tab. 9, 10). The sensitivity of the isotopic study with labeled white
blood cells in detection of graft infection was 88%, specificity was 97%,
accuracy 93%, positive predictive value 96%. Other useful diagnostic procedures
in detection of aortic graft infection are: computed tomography with an accuracy
of 75%, endoscopic investigation useful in detection of arterio-enteric fistulae
with an accuracy of 50% and ultrasonography with an accuracy of 35.5% (Tab. 17).
The choice of the best treatment is still controversial. In my material total
excision of infected graft and extraanatomic revascularization were burdened with
50% mortality rate. Among patients treated less radically the mortality rate was
considerably lower. In a group of patients with the excision of the infected
graft only, the mortality rate was 9% but the amputation rate was 36.4% and in a
group of patients with excision of infected graft and reconstruction in situ, the
mortality rate was 25% (Tab. 18). Taking into consideration our results, less
aggressive methods of aortic graft infection treatment such as the excision of
the infected part of the prosthesis with or without in situ revascularization if
only possible should be recommended. Most common in bacterial cultures from
infected aortoiliac grafts with prosthetic-enteric fistulae were Escherichia coli
found (Tab. 10). In infections without fistula various types of Staphylococcus
aureus were identified (Tab. 9). CONCLUSIONS: 1. In cases of aortoiliac graft
infection the most common cultured bacteria are found to be Staphylococcus
aureus. If there is additional prosthetic-enteric fistula Escherichia coli is the
most common cultured bacteria. 2. In a case there was suspicion of aortoiliac
graft infection, proper diagnostic procedures are most important for effective ma
PMID- 9766087
TI - An invitation to join in difficulty: realizing the deeper promise of group
psychotherapy.
AB - Group psychotherapy has proven effective in treating an impressive array of
specific problems. Clinical experience has also shown its utility in alleviating
the more general, and very costly, alienation and pain with which the human
condition is often fraught. Recent changes in health care delivery reflect a
marketplace that emphasizes cost containment, brevity and specificity of
treatment, and a narrowed focus of training. Techniques are often valued above
relationships. In this climate, we are in danger of losing sight of group
therapy's deeper promise; the experiential lesson that human beings must move
toward each other with involvement and a commitment to understanding in response
to the inevitable difficulties that arise as we share time, space, and resources.
PMID- 9766088
TI - Course design: an integration of didactic and experiential approaches to graduate
training of group therapy.
AB - Graduate training programs attempt to teach group therapy courses using
experiential learning methods and theoretical concepts. Presently, however, these
courses often maintain a rather unstructured format for fostering an experiential
group process. The literature suggests that without standardized course
objectives, students are vulnerable to harm and inadequately prepared for
professional demands, and faculty are insufficiently prepared with guidelines for
instruction. This article reviews the historical evolution of experiential
courses, raises questions about the ethical integrity of such courses in their
current form, and proposes a new course design that integrates essential
components of learning theory. Standards for integrating a developmental approach
to learning, beginning with didactic tasks and advancing to more experiential
tasks, more effectively uphold ethical principles, provide an outline for
comprehensive instruction, and enhance student learning.
PMID- 9766089
TI - Psychodynamic-supportive group therapy model for elderly Holocaust survivors.
AB - The physical and mental consequences of the Holocaust combined with difficult
present events and the problems of old age can have devastating effects on
survivors. Our clinic has recently introduced a psychodynamic-supportive group
therapy model for elderly Holocaust survivors. The model includes specific
integrative interventions, which are based on Horowitz's model of mourning and
coping with stress and the leaders' clinical experience. The aim of the group is
to improve the patients' homeostasis and enhance their ego functions and
adaptation to inner and outer worlds. The theory and working model are described.
PMID- 9766090
TI - A relational approach to group therapy for women with bulimia nervosa: moving
from understanding to action.
AB - This article explains how the psychology of women can inform group treatment by
translating relational theory (RT) into practice within a short-term outpatient
bulimia group. First, the article provides a brief overview of a relational
understanding of women's psychological development, the etiology and maintenance
of bulimia nervosa, and group psychotherapy. Then, clinical vignettes illustrate
the application of RT in practice through discussion of four main healing factors
at work in the different stages of the group. Through promoting validation, self
empathy, mutuality, and empowerment, the leader helps group members identify and
change relational patterns that have kept them connected with food and
disconnected from themselves and others. The goal of treatment is to help members
move toward mutually empathic and empowering relationships inside and outside the
group.
PMID- 9766091
TI - The advanced-stage therapy group.
AB - Many authors describe a stage of maturity in the development of groups, but each
highlights a different dimension. This article describes the characteristics of
the advanced stage and the main axes along which it develops (internalization and
containment, symbolization, self and self-other development, differentiation and
individuation). It also offers a conceptual explanation for these developments
and attempts to identify the conditions necessary for the emergence of this stage
of maturity. An understanding of this stage and the conditions required for its
development can be used by the group leader as a compass to help him or her
navigate the group toward this objective.
PMID- 9766092
TI - Envy in the group-therapy process.
AB - The origins and vicissitudes of envy are discussed from the viewpoints of Boris
and the Kleinians. Their ideas, coupled with a relational perspective of the
therapeutic process, enrich our understanding and inform our work concerning the
emergence, processing, and working through of envy in the therapy group. A
variable in the negative therapeutic reaction, envy can be destructive to the
therapy process. It is proposed that envy, accompanied by shame and guilt, is
likely to enter the group via enactments. They are fueled by projective
identification, which, if ignored, impede the continuation of the group process.
Four clinical vignettes illustrate how envy enters the group and how the group
functions as a container and transformational object as it processes the
projective identifications and works through the enactments.
PMID- 9766093
TI - Group psychotherapy for women molested in childhood: psychological and somatic
symptoms and medical visits.
AB - Molested women who completed a series of 16 weekly group psychotherapy sessions
conducted by social workers improved substantially regarding various aspects of
psychological functioning, including self-image, coping techniques, relationship
issues, and mothering. In addition, there was significant improvement in all
psychological symptom scales and all global indices of symptomatic distress
measured by the SCL-90-R. Furthermore, the improvement was present immediately
after therapy and, with the exception of the hostility score, persisted 1 year
later. Although the somatization score was reduced, the number of visits for
physical symptoms did not change. The patients studied manifested characteristics
typical of previously surveyed women with a history of childhood abuse, including
a frequent history of major surgery (Drossman et al., 1996; Longstreth & Wolde
Tsadik, 1993; Springs & Friedrich, 1992) and, in some, a previous problem with
alcohol (Springs & Friedrich, 1992; Walker et al., 1995) or drugs (Longstreth &
Wolde-Tsadik, 1993; Miller & McCluskey-Fawcett, 1993; Springs & Friedrich, 1992).
Also, nearly one half of the subjects had irritable bowel syndrome, the
prototypical functional bowel disorder (Drossman et al., 1995; Longstreth & Wolde
Tsadik, 1993; Scarinci et al., 1994; Walker et al., 1995). Most of their baseline
SCL-90-R scores were > 1 SD above the nonpatient norms. A problem inherent in
assessing the long-term benefit of this study and other group psychotherapy
studies is the tendency for some patients to continue similar or different forms
of therapy after completing the group sessions. More than one half of patients
received subsequent therapy that could have influenced their status at 1-year
follow-up. However, most of the symptom dimensions and all global indices were
similar 1 year posttherapy in the women who did not receive more treatment as
compared to results in the women who did. Patients who received additional
therapy had higher somatization scores before, immediately after, and 1 year
posttherapy; scores in the other group increased 1 year posttherapy. Although the
indications for subsequent therapy were not surveyed, there was an association
between additional psychological care seeking and somatization. Furthermore,
improvement in psychological status reflected by the phobic-anxiety score
immediately posttherapy may have contributed to the decision of some patients to
seek subsequent therapy. In the group without additional treatment, the loss of
some of the initial somatization improvement at 1 year may have contributed to
the lack of reduction in medical care visits in the combined groups. We speculate
that provision of additional therapy to more patients might have had a long-term
effect on somatization and reduced medical visits. We obtained complete
psychological data and nearly complete medical-visit data on our patients, and
our survey included 1-year follow-up. Our survey did not meet rigorous
methodological standards for an outcome study, however. We surveyed only a small
number of patients and did not collect similar data on an untreated control
group. It was not possible to distinguish health care visits for organic versus
functional disorders, but such a distinction may be artificial, because
psychological factors may influence health care seeking for "organic" illness.
Because our measurements came from a subset of our patients who were willing to
complete the survey questionnaires, we do not know how generalizable the findings
are. There is increasing awareness among health care professionals that childhood
sexual abuse is common and that it may have serious and long-term psychological
and medical sequelae. Our data suggest that group psychotherapy by social workers
for women victims may have long-lasting psychological and somatic symptom
benefits. Reduction in health care usage was not found, and this outcome may
require the identification and treatment of patients who need additi
PMID- 9766094
TI - [Artemisia annua for the treatment of malaria].
PMID- 9766095
TI - Xenoestrogens, pollution & health: a critical review.
AB - This review article provides basic information concerning the xenoestrogens (i.e.
the sexual hormone mimetic or disruptive compounds) in a perspective willingly
selective of the recent literature. In the second part, a hypothetical link
between xenoestrogens and disturbances of the central nervous system is
considered with respect to steroids more directly involved in the CNS, i.e. the
neurosteroids. The data accumulated so far on xenoestrogens present in the
environment and their possible competition for membrane-bound neurosteroid
receptor sites lend support to the working hypothesis that human behaviour could
be affected in the daily life by exposure to chemical pollutants.
PMID- 9766096
TI - [Reactions and interactions of drugs].
PMID- 9766097
TI - 'Public health malpractice, plain and simple'.
PMID- 9766098
TI - NIDR and other factors.
PMID- 9766099
TI - Invading the oral cavity.
PMID- 9766100
TI - About diamond burs.
PMID- 9766101
TI - Insurance standards.
PMID- 9766102
TI - Stress causes slow healing.
PMID- 9766103
TI - At what age do you hope to be able to hang up your high-speed handpiece and
retire?
PMID- 9766104
TI - Sociodemographic distribution of pediatric dental caries: NHANES III, 1988-1994.
AB - This article examines the extent to which caries prevalence and untreated caries
vary in children by ethnicity and household income level. Data from the Third
National Health and Nutrition Examination Survey, 1988-1994, for 10,332 children
2 to 18 years of age indicate that lower-income children and Mexican-American and
African-American children are more likely to have a higher prevalence of caries
and more unmet treatment needs than their higher-income and non-Hispanic white
counterparts.
PMID- 9766105
TI - Aerosol and splatter contamination from the operative site during ultrasonic
scaling.
AB - As concern about indoor air quality increases, attention is being placed on the
aerosol and splatter produced during dental procedures. This study quantifies the
contamination produced by ultrasonic scalers during in vitro scaling without
coolant water. When compared with the handheld curette used as a control, all
ultrasonic scalers and tips tested produced significant aerosol and splatter
regardless of the type of scaler, the power level or the insert. The ADA
recommended method for controlling contaminated aerosol and splatter is the use
of a large-bore high-volume evacuator. This study supports the ADA recommendation
of use of a high-volume evacuator whenever ultrasonic scaling is performed.
PMID- 9766106
TI - The efficacy of an intraoral fluoride-releasing system in irradiated head and
neck cancer patients: a preliminary study.
AB - This study compared the anticaries effectiveness of an intraoral fluoride
releasing system, or IFRS, with a standard regimen of daily application of a 1.1
percent neutral sodium fluoride gel in custom trays. Caries protection in
subjects in the IFRS group was comparable to that in subjects in the 1.1 percent
neutral sodium fluoride group. The subjects all had head or neck cancer and had
received radiation therapy, but no more recently than three months before taking
part in the study. Overall, IFRS devices were well-tolerated and patient
satisfaction was high. The IFRS appears to offer several advantages over the
daily application of fluoride gels in custom trays.
PMID- 9766107
TI - How dentition status and masticatory function affect nutrient intake.
AB - The authors examined nutrient intake in relation to the number of teeth, denture
type and masticatory function among 638 men in the U.S. Department of Veterans
Affairs Dental Longitudinal Study. They found that calorie-adjusted nutrient
intakes decreased with progressively impaired dentition status, independently of
age, smoking status and alcohol use. Intakes of fiber and most vitamins and
minerals were inversely correlated with masticatory function. The findings
suggest that prevention of tooth loss and prosthodontic replacement of missing
teeth could improve diets of older adults.
PMID- 9766108
TI - Eleven myths of dentoalveolar surgery.
AB - Through the years, dentists who perform dentoalveolar surgery have perpetuated
many myths and other unproven beliefs from one generation to another. Sometimes,
these beliefs originated in older textbooks, while others were given birth by
mentors sharing anecdotal experiences with their students. Even today, many of
these scientifically unsupported statements are perpetuated in surgical textbooks
and in continuing education forums and are passed on to students in dental
schools. In today's evolving environment of evidence-based medicine and
dentistry, these anecdotal observations do not withstand scrutiny. The purpose of
this article is to review the more common surgical myths and to test their
validity against scientific evidence.
PMID- 9766109
TI - Selecting drugs for the pregnant dental patient.
AB - When treating pregnant patients, dental practitioners should avoid prescribing
some drugs routinely used for local anesthesia, sedation, analgesia or infection.
Dental practitioners need to determine that the potential benefits of the drug
required for the mother's dental care outweigh the risks to her fetus. This
article briefly reviews the relative risks of therapeutic agents commonly used in
dental care to help practitioners select the safest drugs for use by pregnant
patients.
PMID- 9766110
TI - A simple technique for adjusting and polishing a soft splint.
PMID- 9766111
TI - Dental procedure fees 1975 through 1995: how much have they changed?
AB - A shift toward diagnostic and preventive dentistry in the last two decades is
evident from the change in the number of dental procedures performed, as well as
the change in the percentage of time spent performing different types of
procedures. During the period 1975 through 1995, the average nominal fees for
selected dental procedures increased. Once inflation was taken into account,
however, the increase in the average real fees charged was more modest.
PMID- 9766112
TI - Pulp capping 1998.
PMID- 9766113
TI - Building a dynamic picture of the dental and craniofacial complex: progress in
imaging.
PMID- 9766114
TI - The inappropriate patient.
PMID- 9766115
TI - Improved clinical decision-making using the evidence-based approach.
AB - This article summarizes the evidence-based approach, a comprehensive and rigorous
method for evaluating information, improving decision-making and implementing
clinical treatment. The participants in The American Academy of Periodontology
World Workshop assessed the evidentiary status of periodontal and implant
treatment using the evidence-based approach. The major goal of the Workshop was
to improve treatment decisions by increasing the strength of the inference that
practitioners can derive from the base of knowledge contained within the
literature.
PMID- 9766116
TI - Periodontal diseases: epidemiology and diagnosis.
PMID- 9766117
TI - Prevention.
PMID- 9766118
TI - Periodontal implications: medically compromised patients, older adults and
anxiety.
PMID- 9766119
TI - Periodontal implications: mucocutaneous disorders.
PMID- 9766120
TI - Non-surgical pocket therapy: mechanical, pharmacotherapeutics, and dental
occlusion.
PMID- 9766121
TI - Non-surgical pocket therapy: mechanical, surgical pocket therapy.
PMID- 9766122
TI - Periodontal regeneration around natural teeth.
PMID- 9766123
TI - Mucogingival therapy.
PMID- 9766124
TI - Implant therapy. I.
PMID- 9766125
TI - Implant therapy. II.
PMID- 9766126
TI - Periodontal diseases: pathogenesis and microbial factors.
PMID- 9766127
TI - [Public health work and its advantages as a dilemma of the assessor. Subjective
common sense is a good help].
PMID- 9766128
TI - [Transplantation of the small intestine gives hope of improved survival].
PMID- 9766129
TI - [The most extensive study of artificial insemination. Abnormalities are mostly
common among children born after IVF].
PMID- 9766130
TI - [Is the patient right? A comment to the report from HSU 2000].
PMID- 9766131
TI - [Over-interpretation of the HOT and CAPP studies].
PMID- 9766133
TI - [Correctly organized drug prescription registry is functioning well].
PMID- 9766132
TI - [Treatment of tularemia in children].
PMID- 9766134
TI - [Medical administrators are to blame for unacceptable work place conditions].
PMID- 9766135
TI - [Avoid the mouse-trap! Musculoskeletal injuries can be reduced by placing the
mouse within shoulder space].
AB - Somewhat more than 50 per cent of computer operators complain of problems in the
neck, shoulders or arms. A possible source of such problems may be manipulation
of the mouse. Women are more susceptible than men, possibly due to their smaller
physical size and muscle power. With the mouse placed to the side of the
keyboard, narrow-shouldered computer operators must lift their arm and turn it
sharply outwards. It is preferable to place the mouse within the span of the
shoulders and rest the entire forearm on the desk. A shorter keyboard might be
the answer for narrow-shouldered people.
PMID- 9766136
TI - [Homozygous protein C deficiency can be detected by prenatal diagnosis].
AB - Homozygous protein C deficiency (HPCD) with purpura fulminans is a rare condition
with an estimated incidence of 1-2 per 400,000 births. About 20 case reports have
appeared since the first one was published in 1983. HPCD provides an excellent
illustration of the fundamental importance of the protein C anticoagulant
pathway. This severe coagulopathy results in serious organ damage, often already
in utero, and without treatment it is incompatible with life. The treatment
options include fresh frozen plasma and protein C concentrate in the acute phase,
followed by oral anticoagulant therapy. Over 160 different point mutations in the
protein C gene have been identified in recent years, offering new possibilities
for prenatal diagnosis. The article describes the case of a family who lost two
children with congenital HPCD. But where the specific point mutation was
identified thus enabling prenatal diagnosis to be performed in a subsequent
pregnancy.
PMID- 9766137
TI - [Rehabilitation after myocardial infarction or coronary surgery: elderly patients
may benefit as much as the younger ones].
AB - At most Swedish hospitals participation in cardiac rehabilitation programmes is
restricted to patients of working age, although coronary patients predominately
belong to the higher age groups. The article consists in a review of the benefits
of cardiac rehabilitation to the elderly, such as enhanced quality of life and
lower readmission rates, improvement in co-ordination, muscular strength and bone
mineral constant, and a cardioprotective effect on risk factors. Cardiac
rehabilitation programmes for the elderly, preferably organised in close so
operation between local hospitals, primary care facilities and patient
organisations, might yield considerable individual and general health economic
benefits.
PMID- 9766138
TI - [Chronic mesenteric ischemia. Endovascular treatment is as effective as open
surgery].
AB - Chronic mesenteric ischaemia is a rare but serious condition, which if untreated
may cause death secondary to starvation or bowel infarction. As the symptoms are
sometimes unspecific, its diagnosis may be delayed or missed. Although open
surgical revascularisation has been the traditional treatment, a review of
published reports suggests it to be associated with operative mortality rates of
6-9 per cent, and major morbidity rates of 22-26 per cent. Reports by others, and
our own experience, suggest that endovascular treatment of mesenteric
atherosclerotic obstructions with PTA (percutaneous transluminal angioplasty) and
stenting may yield patency rates differing little from those associated with
surgery, but significantly lower mortality (1.6%) and morbidity (5.6%).
PMID- 9766139
TI - [A developmental project at the pediatric department in Orebro. Physicians were
asked to assess their own competence].
PMID- 9766140
TI - [Tattooing as an aid within plastic surgery].
PMID- 9766141
TI - [Vitamin B12 deficiency surveyed at two health care centers].
PMID- 9766142
TI - [Public health work is improvement without impairment].
AB - Strategies for community intervention, their evaluation and social patterning are
discussed in the article. Theories and methods are called for to enable better
assessment of social inequalities in health outcome variables and processes in
public health endeavours. With this is a starting point some methodological and
ethical issues relating to preventive programmes and their evaluation are
identified.
PMID- 9766143
TI - [Public health work needs new evaluation models. Primary care projects are more
effective than large scale campaigns].
AB - The need both of critical assessment of community intervention programmes and of
alternatives to randomised controlled studies is discussed in the article.
Examples are drawn from a review recently completed for the Swedish Council on
Technology Assessment in Health Care [Statens Beredning for Utvardering av
medicinsk metodik (SBU)], and from the evaluation of a cardiovascular disease
prevention programme currently in progress in northern Sweden.
PMID- 9766144
TI - [The Swedish scissors for plaster of Paris was a sensational discovery. Now more
than 100 years old].
PMID- 9766145
TI - [Should public health recommendations be given generously? Too high demands on
the scientific basis can inhibit preventive work].
PMID- 9766146
TI - [Cat women, fish boys, frog girls... The theory on "impressions in the womb"
still had believers in the 20th century].
PMID- 9766147
TI - [Culture in medicine: the meeting between expectations and unfamiliar health
care].
PMID- 9766148
TI - [200-year anniversary of an epoch-making dissertation on cow-pox. A unique copy
with a dedication in Gothenburg].
PMID- 9766149
TI - [Internationalization of medical education at the Karolinska Institute: students
compare diagnosis and treatment of angina pectoris].
PMID- 9766150
TI - [A special unit for acute cases resulted in shorter length of stay at the
department of surgery].
PMID- 9766151
TI - [University and health care authorities cooperate: new regional continuing
education gives practical knowledge of research methods].
PMID- 9766152
TI - Active listening to cancer patients' stories.
AB - Approximately two thirds of all Dutch cancer patients have severe emotional
problems; shortly after their change from the treatment regime into the regime of
medical controls. Half of them even need professional support. It is, therefore,
important that a professional listens with empathy to the patient's version of
the illness story. Story telling helps to overcome the existential crisis of
being a cancer patient; it is an essential step in the revalidation process.
Themes and open questions which structure the communication are suggested in this
article.
PMID- 9766153
TI - Clinical presentation of sarcoidosis in The Netherlands an epidemiological study.
AB - BACKGROUND: Patients suffering from sarcoidosis may present with a wide range of
symptoms. The aim of this study was to make an inventory of the clinical
presentation of the sarcoidosis population in the Netherlands. METHODS: Symptom
inventory questionnaires were sent to all members of the Dutch Sarcoidosis
Society. Of these 1755 sarcoidosis patients, 1026 (58%), (age 46.7 +/- 11.6,
female 63%) completed the questionnaire. RESULTS: Familial sarcoidosis was
reported by 170 patients (16.3%). In 57% of the cases the first diagnosis was
sarcoidosis. Other diagnosis included rheumatoid arthritis (5.1%) and
tuberculosis (4.8%). Treatment with systemic corticosteroids was reported by 565
patients (55.1%). The most frequently reported symptom was fatigue (71%),
followed by dyspnea (70%), arthralgia (52%), muscle pain (39), chest pain (27%),
and general weakness (22%). Moreover, 26% of patients suffered from disease
related tension and strain. No relationship was found between the reported
symptoms and treatment with corticosteroids. CONCLUSIONS: Sarcoidosis patients
suffered from a broad range of persistent physical symptoms. In this study
fatigue appeared to be the most commonly reported symptom. Intervention programs
should focus on physical health as well as psychosocial aspects such as teaching
patients how to cope with the disease.
PMID- 9766154
TI - Lipid peroxidation in type 2 diabetes: relationship with macrovascular disease?
AB - BACKGROUND: Macrovascular disease is the leading cause of death in diabetes. The
increased risk of atherosclerosis in diabetes may be partly explained by
increased lipid peroxidation. METHODS: We assessed lipid peroxidation in subjects
with type 2 diabetes with (n = 23) and without (n = 23) macrovascular
complications versus healthy age-matched controls (n = 13). The diabetic groups
were matched for glycemic control (mean HbA1c = 9%), and for age had similar
known duration of diabetes. RESULTS: Plasma TBARS were comparable between
diabetic subjects with and without macrovascular complications (1.89 +/- 0.32 and
1.81 +/- 0.28 mumol/l) and elevated compared to healthy controls (1.64 +/- 0.26
mumol/l, p = 0.025). Ratios of IgG and IgM antibodies to oxidized vs. native LDL
were comparable between diabetic subjects and controls, and also between diabetic
subjects with or without macrovascular complications. The lag phase, an index of
the resistance of LDL to oxidation, was significantly longer in diabetic patients
with macrovascular complications (66 +/- 8 min) vs. those without macrovascular
complications and controls (resp. 59 +/- 7 and 56 +/- 7 min, p < 0.05). An
explanation may be the frequent use of drugs with possible antioxidant potential,
e.g. beta-blocking agents, ACE-inhibitors and calcium entry blockers by these
patients. Surprisingly, plasma vitamin E levels were higher in diabetic subjects.
CONCLUSIONS: We found no evidence of increased lipid peroxidation in diabetic
subjects with macrovascular complications, but an increased resistance to
oxidation in this group, probably due to an altered antioxidant status. The
increased TBARS level in diabetic subjects contrasts with the other indices of
lipid peroxidation and may be related to prevalent hyperglycemia and should
therefore be interpreted cautiously.
PMID- 9766155
TI - Chronic tophaceous gout in the elderly.
AB - Gout in the elderly seems to represent a special subgroup. The presentation is
often atypical and drug treatment poses special difficulties. We present two
elderly patients with large subcutaneous tophi leading to grotesque deformities.
Their clinical features, risk factors, diagnosis and treatment are discussed.
Although the appearance and radiographic changes caused by tophi are
characteristic, the definitive diagnosis of tophaceous gout is made by aspiration
and crystal analysis, as is illustrated by colour photographs.
PMID- 9766156
TI - Lymphocytic hypophysitis in a 43-year-old woman.
AB - A woman with sarcoidosis and primary hypothyroidism presented with partial
hypopituitarism without pituitary gland enlargement. A clinical diagnosis of
lymphocytic hypophysitis was established after exclusion of other possibilities,
since a definitive diagnosis can only be made after histological studies. This
rare form of chronic inflammation and destruction of the anterior pituitary gland
is discussed.
PMID- 9766157
TI - Splenic epithelial cysts and splenomegaly: diagnosis and management.
AB - Splenomegaly is a common problem. In the absence of systemic illness or
malignancy splenic cysts must be considered, especially the epithelial variety.
For large cysts total splenectomy has long been recommended. Recognition of the
risk of an overwhelming postsplenectomy infection (OPSI), especially in children,
has led to spleen conserving surgery. We describe the use of an absorbable Vicryl
net after partial splenectomy with total cystectomy in the management of splenic
epithelial cysts.
PMID- 9766158
TI - An interactive approach to training teams and developing programs.
AB - A combination of educational and organizational strategies help rehabilitation
teams develop programs that effectively address the needs of their consumers.
PMID- 9766159
TI - Training professionals for rehabilitation teams.
AB - Transformed treatment philosophies, egalitarian roles, crossover competencies,
and engagement of consumers and families are essentials in training.
PMID- 9766160
TI - A systems approach to developing staff training.
AB - This chapter shows how concepts from organizational psychology can be used to
design a comprehensive staff training model for a statewide mental health service
system, and emphasizes the importance of competency identification in this model.
PMID- 9766162
TI - Developing effective team leaders.
AB - For most staff, the most challenging leadership role they will play is their
first. This chapter describes a research-based training program being developed
to help these leaders increase their effectiveness in this first role.
PMID- 9766161
TI - Total quality management in behavioral health care.
AB - The literature on total quality management or continuous quality improvement in
the behavioral health care field is just beginning to emerge. Although most of
the evidence on its effectiveness remains anecdotal, it seems clear that it can
work in behavioral health care organizations with strong leadership support and a
long-term commitment.
PMID- 9766163
TI - Training for state-funded providers of assertive community treatment.
AB - This chapter describes a training program for state-funded providers of assertive
community treatment services in Illinois and presents results of the evaluation
of the didactic education component.
PMID- 9766164
TI - Consumers as providers in psychiatric rehabilitation.
AB - Issues that arise in employing consumers as providers in psychiatric
rehabilitation programs include readiness of the sponsoring agency, consumer
disclosure, and adjustments in employment practices. Psychiatric rehabilitation
agencies are obligated to seriously consider employing consumers, since they
frequently ask the same of the other organizations.
PMID- 9766165
TI - Psychiatric rehabilitation technology: operationalizing the "black box" of the
psychiatric rehabilitation process.
AB - Psychiatric rehabilitation technology helps practitioners involve their consumers
more fully in the process, act more forcefully on their behalf, and more
accurately document the process and its outcomes.
PMID- 9766166
TI - Burden on the families of patients with schizophrenia: results of the BIOMED I
study.
AB - The burden, the coping strategies and the social network of a sample of 236
relatives of patients with schizophrenia, living in five European countries, were
explored by well-validated assessment instruments. In all centres, relatives
experienced higher levels of burden when they had poor coping resources and
reduced social support. Relatives in Mediterranean centres, who reported lower
levels of social support, were more resigned, and more often used spiritual help
as a coping strategy. These data indicate that family burden and coping
strategies can be influenced by cultural factors and suggest that family
interventions should have also a social focus, aiming to increase the family
social network and to reduce stigma.
PMID- 9766167
TI - Social and clinical factors influencing the choice of coping strategies in
relatives of patients with schizophrenia: results of the BIOMED I study.
AB - The impact of social and clinical factors on the choice of coping strategies of a
sample of 236 relatives of patients with schizophrenia, living in five European
countries, was explored using well-validated questionnaires. The adoption of
problem-focused coping strategies was more frequent among young relatives and
among relatives of younger patients, and was associated with higher levels of
practical and emotional social support and of professional help. In contrast,
emotion-focused strategies were more frequently adopted by relatives who had been
living longer with the patient and who had poorer social support. It is suggested
that supportive and educational interventions should be provided as early as
possible to relatives of patients with schizophrenia, which, in addition to
having a practical focus, should also have a social focus, aiming at extending
the family's social network.
PMID- 9766168
TI - Sex differences in the course of depression: evidence from a longitudinal study
of a representative sample of the Belgian population.
AB - Outcome studies of major depression indicate high rates of relapse and
chronicity, and social role theories imply that chronicity should be greater for
women, together suggesting that the well-known sex difference in depression is,
at least partially, the result of differences in chronicity. Due to a lack of
prospective longitudinal research answers to this empirical question are missing.
Furthermore, the results of the few available surveys of the general population
are inconsistent, showing either higher chronicity for older women or a lack of
sex differences in the overall course of depression. Using data from three waves
of the Panel Study of Belgian Households (complete data for 3204 women and 2907
men, aged 16 years and older) sex differences in the persistence of depressive
behavior are estimated. Depression is measured using a self-report inventory on
three occasions separated by intervals of 1 year (1992, 1993, 1994). Results show
a significant influence of sex, other sociodemographic characteristics, and
depression severity at baseline on depression persistence. Women experience more
symptoms for a longer period of time, a difference that can be partially ascribed
to sex differences in employment status, education and marital status. The
findings are discussed.
PMID- 9766169
TI - Avoidable mortality among psychiatric patients.
AB - Avoidable mortality is a selection of causes of death considered to be amenable
to health care and thereby used as an indicator of the quality of health care. In
this study avoidable mortality for more than 30,000 psychiatric patients
discharged from any hospital of Stockholm County between 1981 and 1985 has been
followed up in the Cause of Death Register for the period 1986-1990. Standardised
rate ratios were calculated for different groups of psychiatric disorders
compared to the general population of Stockholm County for indicators of
avoidable mortality, suicide, other mortality ("unavoidable") and causes possibly
related to treatment with psychotrophic drugs. As expected, the psychiatric
patients had the most pronounced elevated risk for suicide. i.e. 6- to 24-fold
compared to the general population, and noticeably more elevated for women. It is
also noteworthy that the relative mortality risks for diagnoses amenable to
medical interventions and potential side-effects of psychotrophic drugs are
higher than for other causes of death ("unavoidable"). The relative risks for
avoidable mortality were 4.7 for men and 3.8 for women and for diagnoses possibly
related to side-effects of psychotrophic drugs, 7.2. The relative risks for
"unavoidable" mortality were 3.4 for men and 3.2 for women. The excess avoidable
mortality rates for psychiatric patients and the elevated suicide risk,
especially for female patients, are warning signals of shortcomings in
psychiatric care that warrants further investigation.
PMID- 9766171
TI - Abuse of and dependence on alcohol in Swedish women: role of education,
occupation and family structure.
AB - The present study, which is part of a multipurpose study on alcohol use among
women, focuses on the association between education, occupation, family structure
and development of alcohol dependence or abuse in women. A total of 316 women
were selected by stratified random sampling from all women in a defined part of
Gothenburg, Sweden. In a face to face interview, questions were asked about
occupation, education, family structure and other variables reflecting
socioeconomic conditions and relations within the family. As outcome measures we
used alcohol dependence and abuse (ADA), diagnosed in a clinical interview
according to the Diagnostic and Statistical Manual of Mental Disorders, Third
Edition-Revised (DSM-III-R). We found that never having been married, or having
poor communication with the spouse, as well as having no children at home to take
care of, were strongly associated with ADA in women. The role of social class
depended on whether education or occupation was used as a measure. Our findings
are compatible with the hypothesis that development of alcohol-related problems
among women to a large extent is influenced by matters that relate to home and
private life.
PMID- 9766170
TI - The TAPS project 32: social networks of two group homes ... 5 years on. Team for
the Assessment of Psychiatric Services.
AB - Long-stay psychiatric patients discharged to two group homes from Friern Hospital
were studied 1 year and 5 years after discharge. A much greater cohesiveness of
social relationships was noted in the smaller home at both time points, whereas
in the larger home residents had failed to develop friendships and intimacy
within their social group. A number of hypotheses were explored to explain this
difference. None of the factors investigated provided an explanation, including
the mental state of the patients prior to discharge, their problems of social
behaviour, the size of the group homes, whether they were staffed or unstaffed,
and the patients' age. However, the development of friendships and intimacy over
a 5-year period was strongly determined by the quality of the patients' social
networks while in hospital. Consequently, when selecting groups of patients to
share homes in the community, it is deemed advisable to form groups that fully
reflect the range and diversity of their social networks.
PMID- 9766172
TI - The Italian version of the Family Assessment Device.
AB - The aim of the study was to evaluate in a heterogeneous. Italian sample (n = 340)
the psychometric properties of the Italian version of the Family Assessment
Device (FAD), a 60-item questionnaire assessing family functioning. The
questionnaire was administered to psychiatric (n = 116), medical (n = 114) and
non-clinical samples (n = 110). In a sample of 30 non-clinical subjects the
temporal stability of the FAD was investigated. The results showed a good
temporal stability for Problem Solving, General Functioning. Communication, and
Affective Responsiveness scales, and a good internal reliability of the scale.
Factor analysis of the Italian version provided discrepancies with the
hypothesized structure of the instrument, leading to the identification of seven
slightly different dimensions. The proposed seven-factor model of the instrument
did not provide a good fit to our data. The results of our study suggest the need
for a major improvement in the adaptation of the FAD in the Italian setting.
PMID- 9766173
TI - The nitroxidergic neuron in central and peripheral nervous system and related
paraneural structures.
PMID- 9766175
TI - After your heart attack.
PMID- 9766174
TI - Dental microwear. Morphological, functional and phylogenetic correlations.
AB - Dental wear, at first considered a pathological condition, is now regarded as a
physiological mechanism of teeth adaptation to continuous masticatory stresses.
Excessive wear is limited by characteristic structural adaptations of dental hard
tissues showing a phylogenetic trend and specialisation. Enamel is the main
tissue subjected to wear; however, advanced enamel wear exposes increasingly
large areas of dentine. Enamel hardness and anisotropy are the major factors
contrasting wear and microfractures. Anisotropy is mainly related to the
different orientation of prism bundles (and of hydroxiapatite cristals). Enamel
wear development is also related to differences in microhardness, density,
mineral composition and protein distribution. Masticatory loads distributed along
the enamel-dentine junction uniformly disperse in the underlying dentine. In
spite of its structural characteristics, dentine is relatively isotropic by the
functional point of view. Even if its lower hardness opposes less efficaciously
to wear, its biomechanical characteristics successfully contrast microfractures.
The study of microwear (namely the microscopic analysis of worn dental surfaces)
can be made both on original surfaces and on high definition silicone-resin
replicas. Scanning electron microscope observations allow identification of
surface damage (microtraces) produced by different physical and chemical agents.
Microwear analysis may provide indications about alimentary and non alimentary
habits, masticatory biomechanics and pathological situations (e.g., bruxism).
PMID- 9766176
TI - Herbs for the prostate.
PMID- 9766177
TI - Teaching hospitals score well.
PMID- 9766178
TI - I am 61 years old, and for about six years I've been taking Mevacor for my
cholesterol. My doctor is pleased with my results, but I read a newspaper ad that
said Pravachol was better. Should I ask for a new prescription?
PMID- 9766179
TI - Should you take drugs for cholesterol?
PMID- 9766180
TI - Kicking painful leg cramps.
PMID- 9766181
TI - Dizziness: preserving your sense of balance.
PMID- 9766182
TI - New hope for Parkinson's disease.
PMID- 9766183
TI - Is it a good idea to have a chest x-ray as part of a routine physical?
PMID- 9766184
TI - Does tooth bleaching work and is it safe?
PMID- 9766185
TI - What is a CEA test?
PMID- 9766186
TI - Etienne-Jules Marey, founder of the graphic method.
PMID- 9766187
TI - Localization of Myf-5, MRF4 and alpha cardiac actin mRNAs in regenerating Xenopus
skeletal muscle.
AB - We have analysed the spatial and temporal expression patterns of Myf-5, MRF4 and
alpha cardiac actin mRNAs during muscle regeneration following cardiotoxin injury
in adult Xenopus laevis using in situ hybridization. Myf-5 transcripts began to
be detected in the activated satellite cells as early as the beginning of the
regeneration process, then dramatically decreased in young plurinucleated
myotubes. MRF4 mRNA was detected later, just before the young myotube stage, and
was strongly expressed during the different stages of the maturation of myotubes.
Like Myf-5, alpha cardiac actin mRNA began to accumulate early in activated
satellite cells. These results, which contribute to an overview of the expression
of the genes coding for myogenic bHLH proteins during muscle regeneration, are
discussed in relation to the expression of these factors during development.
PMID- 9766188
TI - Hb Nancy and Hb Osler: two distinct genetic variants with identical clinical and
hemoglobin phenotype.
AB - Three hemoglobin variants (Hb Nancy, Osler and Fort Gordon), carrying the same
Tyr-->Asp substitution at position beta 145 (HC2), have been independently
described in 1975 in patients with marked polycythemia. The first one was found
in a French caucasian family from Lorraine, and the two others in African
Americans. Two unrelated individuals with Hb Osler have been recently
reinvestigated at the DNA level and surprisingly, in their beta gene, codon 145
was found to be AAT which encodes for asparagine and not for aspartic acid, the
aspartate at the protein level resulting, thus, from a very efficient
posttranslational event. We reinvestigated a patient from the family of Hb Nancy
and found that codon 145 was GAT, encoding for aspartate. This demonstrates that
Hb Nancy is genetically distinct from Hb Osler despite an almost identical
phenotype.
PMID- 9766189
TI - Trajectory formation and speed-accuracy trade-off in aiming movements.
AB - The trade-off between speed and accuracy and the patterning of movement
kinematics have been central issues for theories of human movement for almost a
century. In the present contribution experimentally obtained kinematics of
reciprocal aiming movements, performed under different task conditions, are
modelled as resulting from a single non-linear dynamical system whose parameters
vary so as to respond to the task demands. Providing a unified account of speed
accuracy trade-off and trajectory formation phenomena, the model offers a
theoretical framework in which both discrete and continuous movements, performed
along one or more dimensions can be understood.
PMID- 9766190
TI - [Frequency of the coreceptor CCR5 gene delta 32 mutation in different French
regions].
AB - We studied the frequency of the coreceptor CCR5 gene delta 32 mutation on 1,836
DNA samples originating from ten French regions. This mutation confers, in the
homozygous state, resistance to HIV-1 infection. For the whole territory, the
mean percentage presence of the delta 32 mutation is 9.2%. The mutation is
statistically more frequent in the north (11.2%) than in the south (6.3%) of the
country; this differentiation corresponds probably to a gradient of decreasing
frequencies of the delta 32 mutation in Europe.
PMID- 9766191
TI - Diets enriched in (n-3) fatty acids affect rat coagulation factors dependent on
vitamin K.
AB - The effects of dietary lipids on haemostasis were investigated in rats fed high
fat diets enriched in saturated fatty acids (SAT), oleic acid (OLEIC), MaxEPA oil
(MaxEPA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) and results
were compared to those for rats fed standard chow (ST). Coagulant activities of
factor IIc and factor VII-Xc were reduced by about 70% in the MaxEPA group and
50% in the EPA and DHA groups relative to the OLEIC, SAT and ST groups. Liver
vitamin K levels were five times lower in the experimental groups than in the ST
group, which would indicate an effect of high fat diets on vitamin K metabolism.
However, only (n-3) fatty acids prolonged the prothrombin time. These components
could act at the post-translational modification level of vitamin K-dependent
plasma clotting factors. The changes in haemostatic factors found in the MaxEPA
group were counteracted by vitamin K supplementation.
PMID- 9766192
TI - [Computer assisted open heart surgery. First case operated on with success].
AB - The recent development of less invasive intracardiac surgery using small
incisions and videoscopic techniques allowed an evaluation of the advantages and
limitations of this new approach. Among the limitations was the increased
difficulty of the surgical technique when using long instruments through small
incisions and ports. We investigated whether computer assisted surgical
instruments might bring a solution to this problem. Among the existing systems,
we selected the Intuitive System because of two original features. It provides a
stable, magnified, three dimensional view of the operating field at a console
where the surgeon is seated to operate, and it uses computer assisted instruments
having the same dexterity and range of motion as the hand. After 10 months of
active work to adapt this system to intracardiac surgery, the first open heart
operation using computer assisted instruments was carried out on a 52-year-old
woman presenting an aneurysm and a large defect of the atrial septum. The patient
was extubated 8 h after the operation, returned to her room 16 h later and was
discharged from the hospital 8 d post-operatively with normal heart function and
no residual shunt. This preliminary experience showed that computer assisted
cardiac surgery is feasible and may open new and promising directions in open
heart surgery.
PMID- 9766193
TI - [The discovery of anaphylaxis: 19 days after an anodyne account of toxicology, it
is shown that immunity is perhaps pathogenic].
AB - While studying the toxicology of various coelenteres fishing filament poisons,
Charles Richet and Paul Portier observed cases of rapid death which had no
correlation with the injected doses. In dogs, death only occurred in those which,
more than 15 days beforehand, had withstood well an injection more concentrated
or identical to the later fatal one. The authors created the neologism
'anaphylaxis' which signifies 'non-protection'. Thus, it appeared that an immune
response could be pathological. This discovery opened the subject area of
immunopathology at a period of time when, in contrast, vaccination and
serotherapy researches were prominent.
PMID- 9766194
TI - Dihydroorotate (dhout) and orotate (orout) utilizer mutants in yeast:
identification of the dhout mutation and allelism of the DHO and URE2 genes.
AB - We induced by UV mutagenesis a series of yeast mutants that were able to utilize
dihydroorotic (dhout) and orotic acid (orout) as precursors for pyrimidine
biosynthesis. These recessive mutations defined three complementation groups
named dhout, orout1 and orout2. The wild-type allele of the gene responsible for
dihydroorotate utilization was cloned using the sensitivity of the dhout mutant
to 5-fluoroorotate. The DHO gene was sequenced and found to be identical to the
URE2 gene. The dhout mutation resulted from the introduction of a stop codon
instead of a glutamine at position 59, which led to the production of a truncated
Ure2p. Therefore, the URE2 and DHO genes are alleles in yeast.
PMID- 9766195
TI - [Substance P in the primary sensory neurons innervating the dental pulp in the
guinea pig].
AB - Primary sensory trigeminal neurons supplying the dental pulp of incisors in
guinea pigs were labelled by retrograde axonal transport. Using an
autometallographic intensification procedure, 48 h after injection of wheat germ
agglutinin/colloidal gold in the pulp, gold particles were detected in the
cytoplasm of the neurons as black granulations. A morphometric study showed a
bimodal repartition of the labelled neurons of the ganglion. By submitting
ganglion slices to an anti-substance P immunserum revealed by
immunocytochemistry, it could be observed that, among the neurons supplying the
dental pulp of incisors, the majority of the largest were substance P
immunopositive while the smallest were substance P immunonegative. These
observations suggest that there could be at least two different populations of
nerve fibres supplying the guinea pig incisor dental pulp. Substance P negative
neurons could express different neurotransmitters.
PMID- 9766196
TI - Lateral dynamic balance reactions to circular translation of the visual field.
AB - Lateral sway of subjects in spontaneous dynamic balance conditions on a seesaw
platform was measured during a visual stimulation monocularly produced by a
rotating glass covered with a prism membrane. Prism rotation induced the
perception of a circular translation of the whole visual field and an ocular
pursuit movement. Therefore, the retinal slip that occurs in normal pursuit was
cancelled. Strong stereotyped postural reactions were observed in a direction
that depended upon both the vertical visual field deviation and the eye
stimulated: upper position of the right visual field induced a leftward sway
resulting from an extension of the right hemibody; symmetrical reactions occurred
for the left stimulation. The results suggest that the postural reactions
recorded depend on the isolated oculomotor activity and, in addition, on retinal
afferences corresponding to the temporal crescent of the stimulated side, which
orientates the postural reaction on the homolateral lower limb muscles.
PMID- 9766197
TI - [Radiation-induced DNA fragmentation evaluated by anti-poly(ADP
ribose)immunolabeling in CHO cells. Standardization with pulsed-field
electrophoresis].
AB - The poly (ADP-ribose) polymerase is an ubiquitous nuclear protein capable of
binding specifically to DNA strand breaks. It synthesizes ADP-ribose polymers
proportionally to DNA breaks. The actual method of reference to determine DNA
double strand breaks is pulsed-field gel electrophoresis, but this requires many
cells. It thus appeared of interest to use poly (ADP-ribos)ylation to follow and
estimate gamma-ray-induced DNA fragmentation at the level of isolated cells after
gamma-irradiation in chinese hamster ovary cells (CHO-K1). The results obtained
by the immunolabelling technique of ADP-ribose polymers were compared to those
obtained by pulsed-field gel electrophoresis. They show that poly (ADP
ribos)ylation reflects the occurrence of radiation-induced DNA strand breaks. A
clear relationship exists between the amount of ADP-ribose polymers detected and
DNA double strand breaks after gamma-irradiation.
PMID- 9766198
TI - Comparison of 14 PCR systems for the detection and subtyping of stx genes in
Shiga-toxin-producing Escherichia coli.
AB - The specificity of 14 polymerase chain reaction (PCR) systems designed for the
detection and subtyping of stx genes was tested on a set of Escherichia coli
strains with known sequences of stx genes. Systems designed for the detection of
genes of the stx1 type did not detect any variant genes of the stx2 type and
conversely, no stx2 type-specific systems detected stx1 variant genes. Among five
stx2 type-specific systems, none detected the stx2ev gene, and two detected the
stx2e gene. Among systems designed for screening genes of the both stx1 and stx2
types with a single primer pair, only one system (the Lin system) was able to
detect stx genes in all studied strains. Shiga-toxin-producing E. coli frequently
carry more than one stx variant gene. Coamplification of stx genes present in the
same strain was demonstrated by restriction of PCR products with endonucleases
generating fragments of variant-specific size. The amplification product obtained
by the Lin system restricted by Hincll yielded fragments of different size for
stx1, stx2, stx2c, stx2e and stx2ev. Thus it was possible to identify different
genes carried in a single strain with a simple two-step PCR/endonuclease
restriction protocol.
PMID- 9766199
TI - Colonization ability and pathogenic properties of a fim- mutant of an avian
strain of Escherichia coli.
AB - Several studies suggest that the expression of type 1 fimbriae is involved in the
virulence of Escherichia coli in chickens, by promoting adhesion of bacteria to
the respiratory tract, which is most probably the first step to occur in the
infection, and by interacting with the immune response. In order to determine to
what extent type 1 fimbriae were involved in the pathogenic process, the fim
cluster of an avian pathogenic strain of E. coli, MT78 (O2:K1:H+), was modified
in vitro and reintroduced in the parent strain via allele exchange using suicide
vector pCVD442. The mutant strain thus generated (DM34) had its entire fim
cluster removed. Its pathogenic properties were compared to those of the parent
strain in an experimental reproduction of avain colibacillosis in 15-day-old
chickens, after primary infection with infectious bronchitis virus followed by
intratracheal inoculation of the challenge strain. In specific-pathogen-free
(SPF) animals, mutant DM34 was less pathogenic than the parent strain and
colonized the lungs of infected animals to a lower level. In germ-free chickens,
although DM34 was less pathogenic than MT78 according to the differences in
weight gains, it colonized the trachea, lungs and internal organs to the same
extent as MT78. Our results suggest that, whereas type 1 fimbriae are not
strictly required in colonization of the respiratory tract of germ-free chickens,
they might be important in establishing a bacterial population in the lungs of
SPF animals. The difference regularly observed in weight gains between mutant-
and wild-type-inoculated chickens reflects a decreased pathogenicity of the fim-
mutant. However, the isolation of E. coli in target organs and the observation of
colibacillosis symptoms and lesions in mutant-inoculated chickens suggest that
type 1 fimbriae by themselves play a limited role in pathogenicity.
PMID- 9766200
TI - Inactivation of mycobacteriophage D29 using ferrous ammonium sulphate as a tool
for the detection of viable Mycobacterium smegmatis and M. tuberculosis.
AB - There is still an urgent requirement for more sensitive, cost-effective methods
for detection and susceptibility testing of mycobacteria in clinical samples. We
have been investigating a simple bacteriophage-based system which could be used
for both purposes. As this depends upon the detection of phages which have
successfully infected cells, a key step is the efficient removal or inactivation
of phages remaining free in the culture medium. We demonstrate here the use of
ferrous ammonium sulphate as an effective agent for the inactivation of
mycobacteriophage D29 without impairing phage replication in previously infected
host bacteria. Using this property, we report the detection of viable
Mycobacterium smegmatis, M. bovis BCG and M. tuberculosis using simple low-cost
technology. The method is highly sensitive, since it is able to detect 10 colony
forming units of M. smegmatis. It is also rapid, with the detection of M.
tuberculosis in sputum specimens within 48 h.
PMID- 9766201
TI - Genetic diversification of methicillin-resistant Staphylococcus aureus as a
function of prolonged geographic dissemination and as measured by binary typing
and other genotyping methods.
AB - The aim of the present study was to determine the extent of genome evolution
among methicillin-resistant Staghylococcus aureus (MRSA) strains. Three different
collections of strains were analysed, comprising locally, nationally and
internationally disseminated genotypes. Various genotyping assays displaying
different levels of resolution were used. Geographically and temporally diverse
MRSA strains comprised the international group. MRSA strains recovered during an
outbreak in a New York City hospital and Portuguese MRSA isolates, all resembling
the so-called Iberian clone, were included in the local and national collections,
respectively. Genotypes were determined by genome scanning typing techniques and
procedures which analyse specific DNA elements only. The outbreak strains showed
subclonal variation, whereas the Portuguese isolates displayed an increased
number of genotypes. Among the epidemiologically unrelated MRSA strains, the
different genotyping techniques revealed a wide heterogeneity of types. Different
typing techniques appeared to show different levels of resolution, which could be
correlated with the extent of geographic spread; the more pronounced the spread,
the higher the degree of genome evolution. Binary typing and randomly amplified
polymorphic DNA analysis are the typing methods of choice for determining
(non)identity among strains that have a recent common ancestor and have undergone
yet limited dissemination.
PMID- 9766202
TI - Differentiation of Brucella melitensis, B. ovis and B. suis biovar 2 strains by
use of membrane protein- or cytoplasmic protein-specific gene probes.
AB - The possibility of differentiating Brucella species and biovars by Southern blot
hybridization of agarose gel-electrophoresed HindIII-digested genomic DNA with
membrane protein- or cytoplasmic protein-specific gene probes was investigated on
92 reference and field strains representative of all known species and biovars.
Based on the RFLP pattern observed, three gene probes, i.e. br25, 39ugpa and
omp16 coding for membrane or cytoplasmic proteins differentiated B. melitensis,
B. ovis and B. suis biovar 2 strains from each other and from the other Brucella
species and biovars. Thus, the use of these specific gene probes could
contribute, in addition to previously identified species- or biovar-specific
markers, to the molecular identification and typing of Brucella isolates.
PMID- 9766203
TI - Development of a polymerase chain reaction assay for identification and detection
of the fish pathogen Flavobacterium psychrophilum.
AB - A PCR-based method was developed to identify and detect Flavobacterium
psychrophilum, the causative agent of "cold-water disease" and "rainbow trout fry
syndrome" in salmonid fish. Two oligonucleotide primers were designed by
comparing the 16S rRNA sequence of all taxa in the genus Flavobacterium and of
representative species in most related genera within rRNA superfamily V. Purified
chromosomal DNAs from all these bacterial species, from 25 F. psychrophilum
isolates and from several other fish-pathogenic bacteria were used to assess the
specificity of the reaction. Amplification products were generated only with F.
psychrophilum DNA. The detection level, equivalent to approximately 10 to 100
bacterial cells, was increased 10-fold by hybridization with a radioactive probe.
Preliminary experiments demonstrated that this procedure can also be applied to
samples of infected tissue. This PCR assay is therefore a rapid, specific, and
sensitive alternative to conventional plate culture methods for the
identification and detection of F. psychrophilum.
PMID- 9766204
TI - Pleiotropic mutations alter the kinetics of calcium transport, competence
regulation, autolysis and experimental virulence in Streptococcus pneumoniae.
AB - Streptococcus pneumoniae is a pathogen in which the extracellular calcium
concentration plays a major physiological role, in growth as well as in the
induction of competence for genetic transformation and activation of autolysis.
Both responses are under the control of a protein activator exported in the
medium. We have checked the impact of mutations which alter the regulation of
competence and autolysis on experimental virulence. Isogenic encapsulated
derivatives carrying the relevant mutations were serotype 3 smooth clones,
obtained by transformation of the relevant rough strains with DNA from a serotype
3 smooth isolate. Survival kinetics and bacterial clearance from the blood were
followed after intraperitoneal infection of Swiss mice with the different
bacterial cultures. In this model, mutants showing an attenuation of virulence
relative to the wild type fell into two classes. In the first, represented by the
lytA::ery mutant V1095 defective for calcium-induced autolysis, attenuated
virulence could be correlated with rapid bacterial clearance from the blood. In
the second, represented by the dmb mutants V2200 and V3300, attenuation was
associated with delayed bacterial clearance from the blood, and correlated with
altered kinetics of calcium transport and of regulation of competence and
autolysis. It appeared unlikely that attenuation of virulence for strains V2200
and V3300 was a direct consequence of their competence phenotype, since the
com::ery mutants V1008 and V1019, defective for the production of the competence
activator, were as virulent as the wild-type strain. Autolysis involving an N
acetyl-muramyl-alanine amidase encoded by lytA was also regulated by calcium. The
inserted allele lytA0::ery further reduced virulence in the dmb1 background
(V2200). This additive effect of lytA- to dmb1 points to different routes of
virulence regulation by LYT and DMB1 and suggests that the kinetics of calcium
traffic controls several pathways involved in the virulence of pneumococcus.
PMID- 9766205
TI - A role for H-NS in the regulation of the virF gene of Shigella and enteroinvasive
Escherichia coli.
AB - We have investigated the role of H-NS, one of the major components of the
bacterial nucleoid, in the expression of the virF gene present on the large
virulence plasmid of Shigella and enteroinvasive Escherichia coli in response to
different environmental conditions. VirF is an AraC-like protein which activates
at least two promoters, virB and virG, both repressed by H-NS. Band shift
experiments reveal that the affinity of H-NS for the virF and virB promoters is
comparable, while the affinity for the virG promoter is higher. Polyacrylamide
gel electrophoresis of three DNA fragments containing the virF, the virB and the
VirG promoters demonstrates, in agreement with computer predictions, that they
have an intrinsically curved structure, confirming the preference of H-NS for
bent DNA. In vivo transcriptional analysis of virF mRNA shows that H-NS
negatively controls the expression of virF at 30 degrees C. The expression of a
virF-lacZ translational fusion in E.coli wild type and in an hns-defective
derivative grown at 30 degrees or 37 degrees C and at pH 6.0 or 7.0 indicates
that, in the absence of H-NS, virF expression becomes insensitive to temperature
and to limited pH changes. Our results strongly suggest that H-NS controls virF
expression by binding to the virF promoter and by repressing its expression at
low temperature and at low pH.
PMID- 9766206
TI - Superficial hydrophobicity in Serratia marcescens strains of clinical origin.
PMID- 9766207
TI - Arguments against the involvement of Borrelia burgdorferi sensu lato in
Alzheimer's disease.
AB - The involvement of spirochaetes, such as the aetiologic agent of Lyme
borreliosis, Borrelia burgdorferi sensu lato, in Alzheimer's disease (AD), a
common neuropathology, has been proposed by several groups in the past. In our
laboratory, brains from 10 AD patients were analysed for the presence of B.
burgdorferi sensu lato by both standard and nested PCR techniques based on
various target regions, such as the hbb gene (encoding the histone-like protein
HBb), the fla gene (flagellin), the rrl-rrf ribosomal intergenic spacer region
and the rrs gene (encoding 16S rRNA). In addition, ELISA and Western blot tests
for the detection of antibodies against spirochaetal antigens were performed on
27 sera from clinical AD patients. Using these methods, we did not obtain any
evidence of the involvement of B. burgdorferi in Alzheimer's disease.
PMID- 9766208
TI - Use of the C3H/He Lyme disease mouse model for the recovery of a Spanish isolate
of Borrelia garinii from erythema migrans lesions.
AB - A skin biopsy from a patient with erythema migrans was inoculated into C3H/He
mice and into culture medium. A Borrelia garinii strain named Rio1 was isolated
from both a direct BSK medium culture and a mouse ear-punch biopsy culture.
Inoculating human tissue into mice produced a disease resulting in severe
inflammation of the left tibio-tarsal joint, development of perivascular
infiltrates as seen in ear-punch biopsies and the spread of spirochaetes along
the skin, far from the inoculation site. The isolation of this strain confirms
the circulation of this Borrelia species in Spain as a human pathogen, as well as
its arthrogenicity in an animal model. The method used to recover strain Rio1
from human tissue is described as rapid and sensitive compared to direct
inoculation of tissue into BSK medium.
PMID- 9766209
TI - Prevalence and characteristics of necrotoxigenic Escherichia coli CNF1+ and CNF2+
in healthy cattle.
AB - From February to July of 1994, 328 faecal samples from 32 herds were collected
and examined for necrotoxigenic Escherichia coli (NTEC). Strains producing the
cytotoxic necrotizing factors type 1 (CNF1) and type 2 (CNF2) were found on 4 and
63% of the farms, respectively. The proportion of animals infected within each
herd varied from 0 to 38%. NTEC producing CNF2 were significantly more frequently
isolated from calves (24%; 17 of 71) than from cows (4%; 11 of 257) (chi 2corr.
25.088; P < 0.001). Although the bovine CNF2+ strains belonged to 16 different
serogroups, 5 (O15, O77, O88, O142 and O153) accounted for 44% of strains. This
study confirmed that healthy cattle are a reservoir of NTEC producing CNF2, and
revealed that CNF2+ strains are more frequently carried by calves than by adult
cows.
PMID- 9766211
TI - Heterotrophic growth on phenolic mixtures by Ochromonas danica.
AB - Because phenols are one of the most common groups of organic pollutants in the
aquatic environment, heterotrophic growth-linked biodegradation of phenol and its
methylated homologues by the eukaryotic alga Ochromonas danica (CCAP 933/2B) was
investigated. The alga grew heterotrophically on phenol and mixtures of phenol
with o- or p-cresols, or with 2,5-, 2,6-, 3,4- or 3,5-xylenols as the sole
sources of carbon in the dark at 25 degrees C. Commensurate with growth, the alga
removed phenol, both cresol isomers and 2,5- and 3,4-xylenols from the growth
media over the incubation periods. In every case, phenol was removed
preferentially to the methylated cosubstrates, but the rates of removal for
phenol were slower than in incubations where phenol was the sole carbon source.
PMID- 9766210
TI - Genetic and serological analysis of the immunogenic 67-kDa lipoprotein of
Mycoplasma sp. bovine group 7.
AB - The gene encoding a lipoprotein of 67 kDa, named P67, was cloned from Mycoplasma
sp. bovine group 7 strain PG50 and expressed in Escherichia coli K12. Analysis of
the amino acid sequence derived from the DNA sequence of the P67 gene revealed a
typical prokaryotic signal peptidase II membrane lipoprotein lipid attachment
site and a transmembrane structure domain in the leader sequence at the amino
terminal end of the protein. Protein P67 showed 91% identical amino acid residues
to the lipoprotein P72 of Mycoplasma mycoides subsp. mycoides small colony type
(SC) and 53% identical amino acid residues to a peptide of an unassigned gene on
the genome of Mycoplasma capricolum subsp. capricolum. Antibodies made against
recombinant P67 reacted with a 67-kDa protein in all Mycoplasma sp. bovine group
7 strains tested and also, to some extent, with P72 of Mycoplasma mycoides subsp.
mycoides SC. The gene encoding P67 was present in all strains of Mycoplasma sp.
bovine group 7 analysed, but not in other Mycoplasma sp. of the "mycoides
cluster" and not in the phylogenetically related Mycoplasma putrefaciens. PCR and
restriction fragment analysis revealed that the gene of P67 is conserved in all
strains of Mycoplasma sp. bovine group 7. A specific PCR reaction based on the
P67 gene sequence enabled rapid identification of strains belonging to Mycoplasma
sp. bovine group 7.
PMID- 9766212
TI - Transport of glucose by a phosphoenolpyruvate:mannose phosphotransferase system
in Pasteurella multocida.
AB - Pasteurella multocida was examined for glucose and mannose transport. P.
multocida was shown to possess a phosphoenolpyruvate (PEP):mannose
phosphotransferase system (PTS) that transports glucose as well as mannose and
was functionally similar to the Escherichia coli mannose PTS. Phosphorylated
proteins with molecular masses similar to those of E. coli mannose PTS proteins
were visualized when incubated with 32P-PEP. The presence of an enzyme IIAGlc
which could play an important role in regulation, as described in other Gram
negative bacteria, was detected. The enzymes of the pentose-phosphate pathway
were present in P. multocida growth on glucose. The activity of 6
phosphofructokinase (the key enzyme of the Embden-Meyerhof pathway (EMP)), was
very low in cell extracts, suggesting that EMP is not the major pathway for
glucose catabolism.
PMID- 9766213
TI - Characterization and gene sequencing of a 19-kDa periplasmic protein of
Campylobacter jejuni/coli.
AB - In order to study a 19-kDa protein (p19) of Campylobacter jejuni, we purified
this protein to homogeneity from C. jejuni strain 81,176 by anion exchange
chromatography. The molecular weight of the native protein is 19,000 daltons. P19
was found to be acidic with an isoelectric point of 4.8 and was located in the
periplasmic space of the bacteria. The 20 N-terminal amino acids were sequenced
and no significant similarities with known proteins were shown. A monoclonal
antibody showed that p19 is conserved in the 2 species C. jejuni and C. coli.
Analysis of sera from 23 patients with a Campylobacter-related infection
indicated that p19 is not immunogenic during natural infection in man. The gene
encoding p19 was cloned and no strong homologies with known sequences were
identified. The preparation of a knockout mutant in p19 will enable the
investigation of the function of this cell wall component of Campylobacter.
PMID- 9766214
TI - Implication of cell wall constituents in the sensitivity of Kluyveromyces lactis
strains to amphotericin B.
AB - In Kluyveromyces lactis, the cell wall compositions of Kl (ATCC 96897), a wild
sensitive strain, and Klm (ATCC 96896), a strain resistant to amphotericin B
(AmB), were shown to be very different, since the walls in the latter were
significantly enriched in hexosamine, but had a reduced content in phosphate and
amino acid. In both strains, the cell walls limited their sensitivity to this
antifungal agent. The absence of cell wall increased the sensitivity of the cells
to this polyene by 5 to 10-fold. When the cells were treated with enzymes such as
pronase and chitinase in order to change the cell wall structure just before
inoculation, the yeasts appeared more resistant to the antibiotic. However,
treatments with chymopapain and phospholipase C did not significantly change the
sensitivity of the two strains to this agent. Cells treated with acid phosphatase
displayed a longer lag phase than the control cells. In addition, when cultured
in the presence of AmB, the cells were less sensitive to this agent. The present
results reveal that both a change in the ionic charges of the cell wall and an
alteration in the cell wall structure modified the sensitivity of these yeast
strains to AmB.
PMID- 9766215
TI - Computer identification of Escherichia coli rRNA gene restriction patterns.
AB - A total of 191 strains of Escherichia coli comprising 164 serovar reference
strains and 28 clinical strains were characterized by rRNA gene restriction
patterns (ribotypes) generated after cleavage of total DNA with MluI, ClaI or
HindIII restriction endonucleases and hybridization of fragments with
acetylaminofluorene-labelled 16 + 23S rRNA. A wide diversity of ribotypes was
observed with endonucleases MluI (104 patterns), ClaI (90 patterns) and HindIII
(98 patterns). When MluI was used, 85% of patterns (11 to 15 fragments) shared
five fragments 17.09, 3.94, 3.06, 2.23 and 1.76 kb in size. When these fragments
were used as internal standards, the percent errors in fragment length
determination was half of that obtained with an external standard. Two fragment
size databases of MluI and ClaI ribotypes were built. Automatic identification
was obtained after setting the percent fragment size variation tolerance (error)
at 5%. MluI ribotyping is recommended as a primary epidemiological marker.
Strains with similar MluI ribotype should then be submitted to ClaI ribotyping.
Ribotyping with HindIII can only be the third choice, since the patterns were
often uncertain due to the frequent occurrence of faint bands. Most of the
studied serovars gave discrete patterns and these data provide the basis for a
molecular typing system for E. coli which could possibly substitute for
serotyping when the latter is not available.
PMID- 9766216
TI - Typing of nosocomial strains of Serratia marcescens: comparison of pulsed-field
gel electrophoresis of macrorestriction fragments with biotyping, esterase typing
and ribotyping.
AB - Fifty nosocomial isolates of Serratia marcescens, collected in six Belgian
hospitals between 1986 and 1990, were characterized by using pulsed-field gel
electrophoresis (PFGE) with XbaI. The results were compared with those previously
obtained by three other methods: biotyping, esterase electrophoresis typing and
ribotyping with EcoRI and HindIII. Macrorestriction analysis (42 PFGE groups) and
esterase typing (42 zymotypes) proved to be the most discriminating, followed by
ribotyping (28 ribotypes) and biotyping (10 biochemical profiles). Biotyping
would serve as a screen to identify isolates, due to its accessibility. Esterase
typing provided a reliable tool to make subdivisions within biotypes because of
congruence between biochemical groups and esterase patterns. Additional
discrimination was still achieved by ribotyping and PFGE. It is concluded that
the combined results of these four markers were useful for distinguishing all
epidemic and sporadic isolates.
PMID- 9766217
TI - PCR-based detection of verotoxin-producing Escherichia coli (VTEC) in ground
beef.
AB - Pathogenic strains of Escherichia coli producing verotoxins (VTs) have been
recognized as a cause of human disease, and rapid and sensitive detection tests
are urgently needed to ensure the safety of food, especially ground beef. We
applied two nested polymerase chain reaction (PCR) assays to detect the genes
encoding VT1 and VT2 irrespective of the bacterial serotype. In combination with
a direct sample preparation protocol, we were able to uncover the presence of
about 110 CFU of verotoxinogenic E. coli (VTEC) in 10 g of ground beef. When a
six-hour enrichment was included, we found the detection limit to be in the range
of 1 to 10 bacterial cells per 10 g of ground beef. To evaluate our detection
system, we tested 30 ground beef samples originating from butcher shops in Berne,
Switzerland. One sample yielded positive PCR results for both the VT1 and VT2
genes, indicating the presence of verotoxinogenic E. coli. Finally, 20 food
homogenates, shown to contain E. coli strains by standard culture, were analysed
with our method, and the gene encoding VT2 was detected in one cheese sample. The
results suggest that the described PCR method can serve as a valuable tool for
the surveillance of VTEC contamination of foods.
PMID- 9766218
TI - Protein and peptide secretion by ABC exporters.
PMID- 9766219
TI - Growth dependence of alpha-glucan phosphorylase activity in Thermus thermophilus.
AB - Glycogen from the thermophilic eubacterium Thermus thermophilus has been
characterized by enzymatic, chemical and spectroscopic analysis. With an average
chain length of seven glucose units, the glycogen from T. thermophilus is one of
the most highly branched glycogens known. In contrast to other bacterial species,
in T. thermophilus, accumulation of glycogen appears not be affected by low
nitrogen concentration. For the first time, alpha-glucan phosphorylase activity
and glycogen content were measured throughout the growth cycle of T. thermophilus
in order to gain insight into glycogen metabolism. In contrast to the situation
that prevails in Escherichia coli, additional carbon sources had no effect on
alpha-glucan phosphorylase activity in T. thermophilus. Maximal activity of the
thermophilic enzyme was found in the early logarithmic phase of growth,
suggesting a function of the alpha-glucan phosphorylase in T. thermophilus as an
outgrowth-specific enzyme.
PMID- 9766220
TI - Cloning and sequence determination of a phi AAU2 gene whose product aborts the
phage lytic cycle.
AB - This communication describes the cloning of a 1.8-kb fragment from the genome of
the corynephage phi AAU2, which aborts the phage lytic cycle when cloned on a
high-copy shuttle vector. The associated phenotype, called Apld (aborting phage
lytic development), was revealed by noting the reduced plaque size and lower
efficiencies of plaquing of phi AAU2 cp, a virulent derivative of phi AAU2, on
"Arthrobacter aureus"-C70 Apld+ cells. Adsorption and phage DNA transfection
experiments showed evidence that Apld acted once the phage DNA had entered into
the cell; apld was confined to a single open reading frame (ORF), encoding a
putative 63-aa polypeptide which did not show any homology to proteins contained
in the databanks; apld is followed by an ORF the product of which shows homology
with a protein expressed by the early region of the Streptomyces phage phi C31.
PMID- 9766221
TI - Two iron-regulated putative ferric siderophore receptor genes in Bordetella
bronchiseptica and Bordetella pertussis.
AB - Two iron-regulated genes with deduced homology to TonB-dependent ferric
siderophore receptors were cloned from Bordetella bronchiseptica by screening a
library of TnphoA insertion mutants. bfrB and bfrC were iron-repressed in B.
bronchiseptica by a Fur-dependent mechanism, and were expressed from promoters
overlapped by potential Fur-binding sites. Both genes were highly conserved among
Bordetella species and were also iron-regulated in Bordetella pertussis. bfrB and
bfrC mutants of both species and a bfrB-bfrC double mutant of B. bronchiseptica
had no discernible defects in utilization of known iron sources for Bordetella.
PMID- 9766222
TI - Replication of the linear chromosomal DNA from the centrally located oriC of
Streptomyces ambofaciens revealed by PFGE gene dosage analysis.
AB - From a cosmid clone of Streptomyces ambofaciens containing the dnaA and gyrAB
genes, a 2.7-kb self-replicating DNA fragment containing the chromosome
replication origin oriC was isolated. This cosmid was previously maped physically
to a region near the middle of the 8-Mb linear chromosomal DNA. A pulsed-field
gel electrophoresis time-course analysis revealed that sequences flanking oriC
were overrepresented relative to the rest of the chromosomal DNA during rapid
growth, indicating that this origin is active. In addition, the terminal regions
of the chromosomal DNA showed a slight overrepresentation at the onset of
stationary phase.
PMID- 9766223
TI - Carnitine acts as a compatible solute in Brevibacterium linens.
AB - Carnitine is a trimethyl amino acid found at relatively high concentrations in
materials of animal origin. Exogenously provided L-carnitine was found to
stimulate growth of Brevibacterium linens ATCC 19391 in media with inhibitory
osmotic strength. Its osmoprotective ability was as potent as that of glycine
betaine. Electrophoretic and spectroscopic (NMR) analysis showed that this
compound is only transiently accumulated, but in significant amounts, by B.
linens under hyperosmotic stress and is converted into glycine betaine. The L
carnitine/glycine betaine pathway is inducible by L-carnitine in B. linens. The D
enantiomer did not improve growth of B. linens, even though this solute is
accumulated by B. linens at the same level as glycine betaine. The two isomeric
forms of carnitine repress the build-up of ectoine, the main endogenous osmolyte
in B. linens.
PMID- 9766224
TI - AFLP typing of Staphylococcus epidermidis in multiple sequential blood cultures.
AB - AFLP is a novel high-resolution PCR-based DNA fingerprinting method generating
complex banding patterns that can be used for comparative analysis. In the
present study, the applicability of AFLP in fingerprinting Staphylococcus
epidermidis isolates was investigated. The criteria considered were stability of
patterns, reproducibility, discriminatory capacity and consistency with
epidemiological context. Repeated testing of strains and investigation of
subcultures showed that AFLP patterns were reproducible and stable with an
intrastrain similarity of S > or = 94% as determined by analysis of digitized
patterns. Fifteen unrelated strains were heterogeneous, with a level ranging from
78-93%. The applicability of AFLP in epidemiological studies of S. epidermidis
was tested on 11 sets of four blood isolates each, from 11 patients with
suspected septicaemia. Nine sets had indistinguishable or highly similar AFLP
patterns for each isolate per set, while two sets had heterogeneous patterns.
These results show that AFLP has high discriminatory power for strain
identification in S. epidermidis.
PMID- 9766225
TI - Homologues of helicase genes priA and ruvAB of Borrelia burgdorferi, the Lyme
borreliosis agent.
AB - A DNA library of strain HB19 from Borrelia burgdorferi sensu stricto, an agent of
Lyme borreliosis, was constructed in the cosmid pLA2917. Genes involved in
initiation of DNA replication and resolution of recombination intermediates
(Holliday junctions) were found on a 23-kbp region up to 0.7 kbp of the "left"
extremity of the linear chromosome in representative species of B. burgdorferi
sensu lato. The potential ruvB gene, located at 22 kbp from the left telomere,
was identified by the similarity of its deduced amino acid sequence to RuvB
(helicases) of other bacteria. B. burgdorferi ruvB is part of an operon which
comprises the homologues of ruvA, queA and pfbB. Expression of the B. burgdorferi
ruvB and ruvA genes renders a wild-type Escherichia coli sensitive to UV light
and mitomycin, indicative of negative complementation. priA, which encodes the
potential recognition factor for the primosome assembly site, was found at 15 kbp
from the left telomere. RuvB and PriA sequences have motifs characteristic of
helicases: a DExH box and an ATP binding site.
PMID- 9766226
TI - Characterization of the Lactobacillus helveticus groESL operon.
AB - This study utilized inverse polymerase chain reactions to characterize a 2.7-kb
region of the Lactobacillus helveticus LH212 chromosome that included two
complete and one truncated open reading frames (ORFs). Protein homology searches
showed that the first two ORFs encoded homologs to the universally conserved heat
shock proteins GroES and GroEL. Amino acids encoded by the 5' end of the
truncated ORF that was downstream of groEL showed good homology to the amino
terminal end of the Streptococcus pneumoniae DNA mismatch repair enzyme HexA.
Nucleotide sequence analysis identified a putative transcriptional promoter
upstream of groES that was comprised of -35 and -10 hexamers flanked upstream and
downstream by copies of the conserved Gram-positive heat shock gene regulatory
sequence, CIRCE. A large inverted repeat that may function as a rho-independent
transcriptional terminator was located between groEL and the third ORF. Northern
hybridization of an LH212 groEL gene fragment to RNA isolated from cells that had
been heat shocked at 52 degrees C for 0, 5, 10 or 15 min detected a 2.2-kb
transcript in each of the cell preparations. Densitometry showed the
concentration of this mRNA species was approximately 4-fold higher after heat
shock for 5 or 10 min and 3-fold higher after 15 min of heat shock.
PMID- 9766227
TI - The 16-kDa alpha-crystallin-like protein of Mycobacterium bovis BCG is produced
under conditions of oxygen deficiency and is associated with ribosomes.
AB - A 16-kDa protein, identical to the alpha-crystallin-like stress protein, was
induced under O2-deficient culture conditions and bound principally to the 30S
ribosomal subunits of Mycobacterium bovis BCG substrain Tokyo (BCG). The 16-kDa
protein was shown to be tightly associated with the ribosome.
PMID- 9766228
TI - Identification and molecular cloning of a novel secretion antigen from
Mycobacterium tuberculosis and Mycobacterium bovis BCG.
AB - A novel protein called SA-5K was identified in Mycobacterium bovis BCG (BCG)
short-term culture filtrates (CFs) by means of a recently described monoclonal
antibody (mAb), L8D8. This protein had an apparent molecular mass (MM) of 5 kDa,
as judged by Western blotting after sodium dodecyl sulphate-polyacrylamide gel
electrophoresis in reducing conditions, and did not seem to contain any sugar or
lipid substituents. In the present work, SA-5K was purified from BCG CFs by
affinity chromatography. A protein that could be detected in Western blot but not
by standard protein staining techniques was obtained. When SA-5K was subjected to
aminoterminal sequencing, the 10 amino acids (aa) found matched the first 10-aa
sequence deduced from an open reading frame (ORF) of M. tuberculosis. The ORF
encodes a polypeptide, likely to include a signal for secretion, with an
estimated MM of 8.3 kDa after signal peptide cleavage. The secretory nature of SA
5K was confirmed by the fact that it could only be detected in CFs, but not in
other BCG subcellular fractions. After size exclusion chromatography, reactivity
with mAb L8D8 was found to peak in the 45-50- and 14-16-kDa fractions. The latter
MM was close to that estimated from the ORF of M. tuberculosis, implying that the
5-kDa antigen detected initially by Western blot in reducing conditions was a
portion of SA-5K released after reduction of a disulphide bridge. The presence of
the gene for SA-5K in BCG and its identity were confirmed by PCR (polymerase
chain reaction) with specific primers and restriction analysis: the PCR product
was slightly shorter in BCG than in M. tuberculosis. The gene coding for SA-5K
was cloned by PCR from BCG and M. tuberculosis DNA and was expressed in
Escherichia coli.
PMID- 9766230
TI - Chitinolytic activity at low temperature of an Antarctic strain (A3) of
Verticillium lecanii.
AB - The chitinolytic activity of Verticillium cfr. lecanii A3, a strain isolated from
continental Antarctica, was compared to those of two selected strains of
Trichoderma harzianum. After 72 h of incubation at 25 degrees C in media
containing chitin as the sole carbon source, all strains showed the same enzyme
activity (ca. 230 mU/ml); at 15 degrees C, the levels of enzyme activity of the
three strains were similar to those obtained at 25 degrees C. At 5 degrees C, in
contrast, the activity of V. lecanii was ca. 4 times higher than those of both
strains of T. harzianum (203 and 57 mU/ml, respectively; incubation time 144 h).
The chitinase of V. lecanii, purified by preparative isoelectric focusing and ion
exchange chromatography, was shown to be a glycoprotein with apparent molecular
weight of 45 kDa and isoelectric point of 4.9. The enzyme was active over a broad
range of temperatures (5-60 degrees C): at 5 degrees C, its relative activity was
still 50% of that recorded at 40 degrees C (optimal temperature). V. lecanii and
its purified chitinase showed clear inhibitory effects on the growth of some test
moulds such as Mucor plumbeus, Cladosporium cladosporioides, Aspergillus
versicolor and Penicillium verrucosum: observations under the light and scanning
electron microscopes revealed that growth inhibition was accompanied by mycelial
damage and cell lysis.
PMID- 9766229
TI - Biomineralization of carbonates by Halomonas eurihalina in solid and liquid media
with different salinities: crystal formation sequence.
AB - Carbonate precipitation by 20 strains of the moderately halophilic species
Halomonas eurihalina in both solid and liquid media was studied. The influence of
salinity and temperature on the quantity and type of crystals precipitated was
also investigated. Some strains of H. eurihalina formed crystals in all
conditions tested. The mineral phases precipitated were magnesium calcite,
aragonite and monohydrocalcite in variable proportions depending on various
factors such as the type of growth medium employed and its salinity. Scanning
electron microscopy and X-ray dispersive energy microanalysis were used to
investigate the crystal formation sequence. The process of biolith formation was
sequential. It started with chains or filaments of bacteria, giving way to discs
which finally produced spherical forms of approximately 50 microns in diameter.
We suggest a mechanism of carbonate crystal formation by H. eurihalina.
PMID- 9766231
TI - Inhibition of Salmonella intracellular proliferation by non-phagocytic eucaryotic
cells.
AB - Salmonella typhimurium is an intracellular pathogen capable of proliferating
within vacuolar compartments of non-phagocytic eucaryotic cells. This process has
been shown to be essential for virulence in the mouse typhoid model (Leung and
Finlay, Proc. Natl. Acad. Sci. USA, 88, 11470-11474, 1990). Here we present
evidence that certain non-phagocytic eucaryotic cell lines, such as 3T3 (mouse
fibroblasts) and NRK (rat fibroblasts) cells, are not permissive for S.
typhimurium intracellular proliferation. Moreover, viability of intracellular
bacteria residing within both cell types notably decreases at late postinfection
times (72 h). These results clearly demonstrate that non-phagocytic eucaryotic
cells are capable of destroying intracellular S. typhimurium. Experimentation
with 3T3 and NRK cell lines might provide an appropriate in vitro model for
identifying new bacterial and/or eucaryotic factors regulating Salmonella
intracellular proliferation within vacuoles of the host eucaryotic cell.
PMID- 9766232
TI - Regulation of the expression of a gene encoding beta-endoglucanase secreted by
Myxococcus xanthus during growth: role of genes involved in developmental
regulation.
AB - An endoglucanase, CelA, is secreted by Myxococcus xanthus only during exponential
growth. The production of this enzyme is decreased by mutations in 5 different
genes (Exc +/- phenotype), three of which correspond to asg genes which regulate
the production of an early cell-to-cell signal in development. Transcription of
celA is decreased in two of these Exc +/- mutants, whereas a post-transcriptional
step is affected in two other Exc- mutants. Thus, asg genes, in addition to
regulating the onset of development, also regulate a gene (celA) that is
expressed during exponential growth and that is not involved in development.
PMID- 9766234
TI - Characterization of catechol- and chlorocatechol-degrading activity in the ortho
chlorinated benzoic acid-degrading Pseudomonas sp. CPE2 strain.
AB - Pyrocatechase activity was studied in the Pseudomonas sp. CPE2 strain, which is
capable of growing on 2-chlorobenzoic and 2,5-dichlorobenzoic acid, giving rise
to catechol and 4-chlorocatechol, respectively, as intermediate metabolites. The
CPE2 crude extract was found to metabolize both catechol and 4-chlorocatechol.
Enzymatic as well as phenotypic studies performed both on this strain and on a
mutant strain lacking the chlorocatechol-degrading genes were consistent with the
presence of two catechol-cleaving enzymes, one active mainly against catechol
(pyrocatechase I) and the other with broader substrate specificity (pyrocatechase
II). The latter enzyme also appeared to be induced when CPE2 cells were grown on
2-chlorobenzoic acid, thus contributing to catechol metabolism, in addition to
pyrocatechase I. Despite the presence of a large plasmid in CPE2 cells, the
chlorocatechol-degrading genes, highly homologous to the clc operon, were located
on the chromosome. The selection at relatively high frequency of mutant strains
with altered growth capabilities and which lacked the chlorocatechol-degrading
genes suggests a transposon-like character for these catabolic genes in the CPE2
strain.
PMID- 9766233
TI - Reaggregation and binding of cell wall proteins from Candida albicans to
structural polysaccharides.
AB - Urea or hot sodium dodecyl sulphate extracted a significant amount of the same
proteins from the matrix of the cell wall of the yeast form and mycelial cells of
Candida albicans. Gel filtration analysis of the urea-extracted proteins revealed
that they occurred in the form of large complexes which were unaffected by up to
8 M urea. Among them, proteins en route to becoming covalently associated within
the wall scaffold were identified by their reaction with specific antibodies.
When urea was removed by dialysis, some of these proteins specifically
reassociated into large aggregates which bound strongly with ConA, whereas others
remained soluble in smaller associated products. The ability of some of these
proteins to bind to the insoluble wall polysaccharides was also assessed. No self
assembling proteins were able to bind to glucans and/or chitin. Specificity of
the binding to polysaccharides made of beta-bound glucosyl or N
acetylglucosaminyl residues was determined by the competitive effect of several
disaccharides. Whereas laminaribiose and diacetylchitobiose were strong
inhibitors of protein binding to both glucan and chitin, lactose, maltose and
sucrose were ineffective.
PMID- 9766235
TI - Combined numerical analysis based on the molecular description of Mycobacterium
tuberculosis by four repetitive sequence-based DNA typing systems.
AB - Mycobacterium tuberculosis clinical isolates (113 isolates from 78 patients) were
typed using IS6110-RFLP, DR-RFLP, DR-based spoligotyping and direct repetitive
element PCR (DRE-PCR). The similarities among isolates were compared for each
individual method. The individual matrix distance files for each method were
summed and averaged, and the resulting unique distance file was analysed by the
UPGMA (unweighted pair group method with arithmetic averages). Combined numerical
analysis with 3 genetic markers (IS6110-RFLP, DR-RFLP and spoligotyping) was
performed for all 78 clinical isolates, whereas analysis with 4 genetic markers
(with the addition of DRE-PCR) was performed on the 10 main clusters described.
When compared to molecular analysis based on individual markers, the molecular
description based on multiple genetic markers enabled comparison of the results
obtained by individual methods and the obtaining of a more accurate view of
strain identity and clusters comparison. The resulting cumulative dendrogram was
more accurate for studying the population structure of M. tuberculosis and may be
a good tool for elucidating intraspecies genetic microevolution.
PMID- 9766237
TI - Cooperation between the components of the meningococcal transferrin receptor,
TbpA and TbpB, in the uptake of transferrin iron by the 37-kDa ferric-binding
protein (FbpA).
AB - Meningococcal TbpAB complexes TbpA, TbpB and FbpA were purified and used to study
their role in the uptake of iron from transferrin to FbpA. Purification was
achieved by affinity chromatography techniques, yielding homogeneous, non
denatured and functional material. TbpA could not be separated from TbpB and had
to be purified from a TbpB-defective mutant strain. FbpA was able to bind iron
from transferrin only when TbpAB complexes, TbpA and/or TbpB, were also present
during the interaction. The highest uptake efficiences were obtained with TbpAB
complexes or TbpA/TbpB mixtures. We conclude that the TbpA and TbpB molecules
form true functional transferrin receptors, that FbpA is able to take iron
directly from transferrin when in the presence of the components of the receptor,
and that both Tbps are necessary for an optimal operation of the uptake system.
PMID- 9766236
TI - Stable electrotransformation of symbiont candidate diazotrophic bacterium with
plasmids carrying selectable and screenable marker genes.
AB - Nitrogen-fixing symbioses had been established between the originally asymbiotic
soil bacterium Azotobacter vinelandii CCM289 and different lower and higher plant
species. Better characterization and further development of such artificial
systems require a reliable genetic transformation method for the introduction of
marker genes into symbiont candidates. The performance of electroporation was
evaluated using pJB3 (4.8 kb), pBI121 (12.8 kb) and pFAJ31.2 (24 kb) plasmid DNAs
containing selectable (Ap, Km, Tc) and screenable (gusA, lacZ) marker genes. The
adapted methods for the preparation of transformation-competent azotobacters and
their electroporation (18 kV/cm electric field strength, 5 ms time constant, 0
degree C) provided up to 6.8 x 10(5) transformants per microgram plasmid DNA,
which is about 10(3) times the transformation efficiency achieved in control
experiments. No electrotransformants were obtained with the 24-kb pFAJ31.2. The
size of plasmid DNA did not significantly affect the efficiency of
transformation. Transformants were able to grow at antibiotic concentrations that
were 100-200 times greater than the lowest amounts that completely inhibited the
growth of wild-type bacteria. A constitutive expression of gusA gene was observed
in transformants with the CaMV 35S promoter-gusA fusion containing pBI121, while
lacZ expression was not detected under the control of the lac promoter in pJB3
transformants. Electroporated plasmids were reisolated from transformants in
their original form, while non-transformed bacteria did not contain indigenous
plasmids. PCR amplification and Southern DNA blot hybridization showed the
integration of plasmid DNA into the host genome as well. Transformants retained
their nitrogen-fixing ability and had normal morphological and growth
characteristics. Experimental findings proved the stable maintenance of plasmid
DNA in azotobacters, making possible the routine transformation and detection of
these symbiont candidates.
PMID- 9766238
TI - Biochemical characterization of tellurite-reducing activities of Bacillus
stearothermophilus V.
AB - Bacillus stearothermophilus V is a naturally occurring Gram-positive rod which
exhibits resistance to potassium tellurite. Crude extracts of this bacterium
catalyse the NADH-dependent, protease-sensitive reduction of K2TeO3 in vitro. Two
fractions which showed the ability to reduce potassium tellurite (H1 and H2) were
obtained. Fraction H1 behaved as a macroaggregate exhibiting a very high
molecular mass that could not be estimated accurately. Upon electrophoresis in
polyacrylamide gels in the presence of SDS, however, it was resolved into three
distinct bands of 60, 41 and 37.5 kDa. On the other hand, an M(r) of 121 was
determined for fraction H2 by means of gel filtration and high-pressure liquid
chromatography. In SDS-PAGE a unique protein band of 60 kDa was observed,
suggesting that it is actually a dimer. Both fractions showed pH and temperature
optima of 7.5 and 57 degrees C, respectively. Concentrations of 2.5 M NaCl or
0.35 mM SDS inhibited fraction H2 almost completely, while fraction H1 retained
20% of its activity under the same conditions. Concentrations of 5 mM EDTA caused
the activity of both fractions to increase 2-fold. In addition to reducing
tellurite, they were also able to reduce Na2SeO3 and Na2SO3 in vitro.
PMID- 9766239
TI - Biodegradation of phenol and p-cresol by the hyphomycete Scedosporium
apiospermum.
AB - A hyphomycete with the ability to utilize phenol and p-cresol as carbon and
energy source was isolated from soil and subsequently identified as Scedesporium
apiospermum. The identification of degradation metabolites and the detection of
the corresponding catabolic enzymes in crude extracts enabled us to propose
different pathways for the degradation of both phenol and p-cresol in this
organism. Generally, the catabolism proceeded via three different dihydroxylated
intermediates (catechol, hydroxyhydroquinone and protocatechuate) which were
intradiolically cleaved by the corresponding inducible dioxygenases and further
catabolized via the 3-oxoadipate pathway.
PMID- 9766240
TI - Mesophilic Aeromonas strains from different serogroups: the influence of growth
temperature and osmolarity on lipopolysaccharide and virulence.
AB - Growth of mesophilic Aeromonas sp. strains from serogroups O:13, O:33 and O:44 at
different temperatures and osmolarity resulted in changes in the
lipopolysaccharide (LPS) and virulence of the strains tested, as we had
previously reported for strains from serogroup O:34. The effect of osmolarity
could be observed when the cells grew at 37 degrees C but not at 20 degrees C.
Purified LPS from cells cultivated at 20 degrees C (high or low osmolarity) or at
37 degrees C at high osmolarity was smooth, whereas the LPS extracted from the
cells cultivated on low osmolarity was rough. The smooth strains were resistant
to the bactericidal activity of non-immune serum, while the rough strains were
sensitive and showed better adhesion to Hep-2 cells than the rough strains.
Furthermore, the smooth strains were more virulent for fish and mice than the
rough strains. For mesophilic Aeromonas sp. strains from serogroups O:1 to O:44,
these changes were not observed, except for serogroups O:13, O:33, O:34 and O:44.
PMID- 9766241
TI - Cellulolytic enzymes of rumen anaerobic fungi Orpinomyces joyonii and Caecomyces
communis.
AB - The rumen anaerobic fungi Orpinomyces joyonii A4 and Caecomyces communis JB1 were
grown on microcrystalline cellulose (MC) and alfalfa hay. The cellular
distribution of cellulases produced by these organisms was monitored. Fungal
cultures were separated into extracellular, intracellular and cell wall fractions
and assayed for endoglucanase (EG) and beta-glucosidase activity. In both fungal
isolates, EG activity was the highest in the extracellular fraction regardless of
the substrate used. The beta-glucosidase activity produced by O. joyonii was
mainly found in the cell wall fraction. On the contrary, the same enzyme activity
in C. communis predominated in the extracellular fraction. The polycentric
isolate A4 more efficiently utilized both substrates, produced more short chain
fatty acids (up to 31 mmol/l) and showed higher total levels of EG (2744 nmol
glucose/h/ml) than the monocentric strain JB1. On the other hand, beta
glucosidase (9033 nmol glucose/h/ml) activity was the highest in cultures of C.
communis grown on cellulose. In cultures of O. joyonii grown on MC, the
production of yellow affinity substance (YAS) with similar properties compared
with yellow substance from Clostridium thermocellum was observed. This compound
increased the adsorption of fungal cellulases to MC the temperature and pH range
tested.
PMID- 9766242
TI - Endemic presence of Salmonella bongori 48:z35:- causing enteritis in children in
Sicily.
PMID- 9766243
TI - 16S-23S and 23S-5S intergenic spacer regions of lactobacilli: nucleotide
sequence, secondary structure and comparative analysis.
AB - Lactobacilli have been used as industrial starters for a long time, but in
several cases their identification was, and still is, neither easy nor reliable.
The aim of the present work was to examine whether the intergenic spacer regions
could be of value in the identification of Lactobacillus species. For that
purpose, the polymerase chain reaction (PCR) was used to amplify 16S-23S and 23S
5S spacer regions of Lactobacillus (L.) acidophilus, L. delbrueckii subsp.
bulgaricus, L. casei, L. helveticus and L. curvatus. The PCR products were
directly sequenced, and two forms of ribosomal RNA (rrn) operons were identified
in each species studied: one with tandem tRNA(Ile)/tRNA(Ala) genes and the other
one without tRNA genes. Our study revealed that the rrn operons of Lactobacillus
species studied comprise the genes of 16S, 23S and 5S rRNA, in that order. Only
the tRNA genes and the rRNA processing stems are highly conserved in spacer
regions of lactobacilli. The divergence between the lactobacilli spacer region
sequences arises from insertions and deletions of short sequences. These
sequences could be interesting candidates for the development of species-specific
probes. Theoretical RNA/RNA secondary structure models of the interaction between
the two spacer region sequences were constructed. In conclusion, the two spacer
region sequences may prove to be a useful alternative to 16S and 23S rDNA
sequencing for designing species-specific probes and for establishing
phylogenetic relationships between closely related species such as L. curvatus
and L. casei or L. acidophilus and L. helveticus.
PMID- 9766244
TI - Transdermal permeation of neutral molecules by skin electroporation.
AB - Electroporation of skin has recently been shown to enhance transport of charged
molecules across skin by up to four orders of magnitude. This study demonstrates
that high-voltage pulses can also increase transdermal permeation of two neutral
model solutes, i.e. mannitol and water, up to 100-fold. The elevated flux results
from the persistent increase in skin permeability following electroporation,
rather than from electro-osmosis during pulsing. Control on transport was
achieved by controlling the electrical parameters of the pulse, i.e. the pulse
voltage, time constant and number.
PMID- 9766245
TI - Kinetics of release of a model disperse dye from supersaturated cellulose acetate
matrices.
AB - A study has been made of the kinetics of release into water of a model disperse
dye (4-aminoazobenzene) from supersaturated solvent-cast cellulose acetate films
at room temperature. Excess dye was introduced into the polymer matrix by: (i)
sorption from aqueous solution at 100 degrees C; (ii) sorption from the vapour
phase at 110 degrees C; or (iii) prior dissolution in the casting solvent. The
effect of the method of introduction of the dye, the degree of supersaturation
and the rate of agitation of the bath were investigated. Under conditions of
strong agitation, the release kinetics from films dyed by method (i) or (iii)
were in general accord with the theoretical model which assumes solute in the
film in excess of the saturation limit to be in the form of immobile aggregates
at equilibrium with mobile dye; although the value of the diffusion coefficient
of the solute in the film was found to be substantially higher than that in the
unsaturated film. On the other hand, when dyeing had been effected from the
vapour phase, Fickian kinetics was followed and the diffusion coefficient was
found to be equal to that observed in unsaturated film. It was concluded that
under these conditions, the excess dye in the film tends to remain molecularly
dispersed. Under conditions of slow agitation, the square root of t kinetics was
not attained in many instances. General and early-time approximate expressions
based on the Roseman-Higuchi model proved useful for the interpretation of the
results in such cases; while the said model was extended to include the effect of
significant variation of the partition coefficient of the solute with
concentration.
PMID- 9766246
TI - Transdermal alniditan delivery by skin electroporation.
AB - The aim of this study was to evaluate the transdermal permeation of alniditan by
electroporation and to compare with iontophoretic delivery. The influence of the
electrical parameters of electroporation was investigated in vitro using a
factorial design study. The transdermal flux of alniditan was enhanced by two
orders of magnitude by application of high voltage electrical pulses. The
electrical parameters of electroporation-i.e. the voltage, the duration and the
number of pulses-allowed a control of drug permeation. Both transport during and
after pulsing were shown to be important for alniditan transdermal delivery by
electroporation. Electroporation was found more efficient in promoting alniditan
permeation than an iontophoresis transferring the same amount of charges.
PMID- 9766247
TI - Methoxy-polyethoxy side-chain silastomers as materials controlling drug delivery
by diffusion flux.
AB - The density of a diffusion medium and the solubility of the diffusant in this
material are predominant parameters which control the diffusion flux. Side-chain
silastomers can be structurally modified in such a manner that density and
polarity are widely varied and adjustable to distinct conditions. The synthesis
of cross-linked methoxy-polyethoxy side-chain polysiloxanes is performed by
reaction of alpha, omega-bis-(trimethyl-silyloxy)-poly-(methyl-hydrogen
siloxane), alpha, omega-divinyl-poly-(dimethyl-siloxane), and 4-propenyloxy-(4'
methoxy-polyethoxy)-biphenyl. Silastomer foils were obtained with side-chains
having up to 9 ethoxy groups. Various silastomer types were characterized by DSC
measurements, polarization microscopy, uptake of water and salicylic acid (as
model drug), and by permeation measurements. The polarity of the polymers depends
on their contents of ethoxy groups influencing the uptake of polar substances.
Polymers with penta-ethoxy and hepta-ethoxy groups at the side-chains take up
water under swelling. The solubility and the distribution coefficients of
salicylic acid are linearly correlated to the weight fractions of the methoxy
polyethoxy groups in all silastomer types. The temperature dependence of the
distribution coefficients of the penta-ethoxy and hepta-ethoxy polymer types
shows deviations from the Arrhenius equation. As the side-chains occupy
considerable volumes, the density of the molecular packing within the cross
linked polysiloxane matrices is high. The arrangement of the side-chain domains,
therefore, depends on the chain length of the cross-linker; the diffusion
coefficients are influenced by this parameter. Evidence for the existence of a
lyotropic liquid-crystalline phase was observed for one type of these polymers
only. Methoxy-polyethoxy side-chain silastomers as membranes or matrices are
suited for controlled drug delivery. Drug liberation rates and swelling by uptake
of water can be widely altered by variations of the side-chain structures.
PMID- 9766248
TI - Degradation and release profile of microcapsules made of poly[L-lactic acid-co-L
lysine(Z)].
AB - Poly(L-lactic acid-co-L-lysine(Z)) with different Lys(Z) contents was synthesized
by Sn(II) salt-catalyzed ring-opening copolymerization of 3(S)
benzyloxycarbonylaminobutyl-6(S)-methylmorpholine-2,5-dione with lactide.
Microcapsules of the copolymers were prepared by solvent evaporation from w/o/w
emulsion, and FITC-dextran release from the microcapsules was investigated. The
FITC-dextran release was dependent on the composition and molecular weight of the
copolymers. The release from the microcapsules containing Lys(Z) of 6.5 mol% was
slowest among the present microcapsules, which is due to smooth surface and very
small microcapsules included in a large microcapsule. On the other hand, the
release from microcapsules containing Lys(Z) of 31 or 50 mol% became faster after
several days of incubation. GPC measurement of the microcapsules revealed that
the copolymers were degraded during the incubation. Cracks and pores were formed
on the microcapsule wall. PLLA microcapsules having comparable molecular weight
to the copolymers showed neither release acceleration nor degradation in short
time incubation. Therefore, the introduction of Lys(Z) units made PLLA
susceptible to degradation to result in delayed acceleration of release.
PMID- 9766249
TI - Development and evaluation on transdermal delivery of enoxacin via chemical
enhancers and physical iontophoresis.
AB - Iontophoresis and enhancers were performed to enhance percutaneous absorption of
enoxacin so as to compare the enhancement between these two enhancing methods.
The cationic surfactant of benzalkonium chloride showed the highest enhancing
activity for enoxacin for all pH values of buffer vehicles. The enhancement
factor of sodium laurylsulfate showed a dose-dependent property between the range
of 0.1% to 3.0% concentration. Nonionic surfactant of Polysorbate 80 did not
exhibit any enhancing effect on the percutaneous absorption of enoxacin. The
highest enhancement factor of iontophoretic delivery was observed at pH 5.0
solution of anodal iontophoresis for cationic enoxacin. The cathodal
iontophoresis of negative molecules and anodal iontophoresis of neutral molecules
showed lower enhancing effect for enoxacin. The fact that the skin residuals of
enoxacin after iontophoresis showed both tremendous and current density-dependent
amounts for cationic enoxacin suggested local skin and soft tissue infections
might be treated by this physical enhancement method. Combination of benzalkonium
chloride and iontophoresis exerted a synergistic effect for anionic enoxacin in
pH 10.0, which was possibly due to the shielding of negative charge in skin and
the water molecules carried by chloride.
PMID- 9766250
TI - Absorption/release of polyvalent metal ions by a polyelectrolyte gel.
AB - The swelling/contraction dynamics of a strongly charged gel immersed in a copper
sulphate solution were studied. Changes in the size of the gel particle and the
penetration of metal ions inside the network were monitored by optical
microscopy. The equilibrium state was attained in two steps: First, the gel
swells, mainly by absorbing water, and then it collapses, to the almost dry
state. The release of copper ions from the contracted gel when it was placed in
acidic medium was studied as a function of time using optical microscopy. The
influence of the acid concentration on the rate of ion release and on changes in
the particle size of the gel are discussed.
PMID- 9766251
TI - Self-assembled hydrogel nanoparticle of cholesterol-bearing pullulan as a carrier
of protein drugs: complexation and stabilization of insulin.
AB - Insulin (Ins) spontaneously and easily complexed with the hydrogel nanoparticle
of hydrophobized cholesterol-bearing pullulan (CHP) in water. The complexed
nanoparticles (diameter 20-30 nm) thus obtained formed a very stable colloid. The
thermal denaturation and subsequent aggregation of Ins were effectively
suppressed upon complexation. The complexed Ins was significantly protected from
enzymatic degradation. Spontaneous dissociation of Ins from the complex was
barely observed, except in the presence of bovine serum albumin. The original
physiological activity of complexed Ins was preserved in vivo after i.v.
injection.
PMID- 9766252
TI - Coupling of the antiviral agent zidovudine to polyaspartamide and in vitro drug
release studies.
AB - A macromolecular prodrug of the known antiretroviral agent zidovudine and alpha,
beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) was synthesized. A succinic
spacer was present between the polymer and the drug, and 1,1'-carbonyldiimidazole
was used as the coupling agent. In vitro drug release studies at pH 1.1, 5.5 and
7.4 indicated that limited amounts of intact drug were released from the
conjugate. At pH 1.1 and 7.4 succinylzidovudine was released, and this was
hydrolysed to give free zidovudine. In the presence of alpha-chymotrypsin,
zidovudine was released preferentially in comparison with the succinyl
derivative. The amounts of released zidovudine and succinylzidovudine were
greater in plasma than in aqueous buffer solutions. These results show that after
i.v. administration this drug-polymer conjugate can release zidovudine into the
blood circulation for prolonged periods.
PMID- 9766253
TI - Enhanced neuroendocrine response to insulin tolerance test performed under
increased ambient temperature.
AB - The hypothesis that an increase in ambient temperature modulates neuroendocrine
response in clinically used provocative pituitary function tests was verified.
Healthy male volunteers were subjected to insulin tolerance tests in two
randomized trials. In the first trial hypoglycemia was induced by a bolus
injection of insulin (0.1 U per kg of BW, i.v.) at room temperature. In the
second trial, the subjects were exposed to increased ambient temperature for 45
min before insulin injection and for 45 min thereafter. The environmental
temperature was selected to increase body temperature less than 1C. Under
conditions of increased temperature basal hormone levels as measured in
antecubital venous blood samples failed to be modified and the hypoglycemia was
less severe. Nevertheless, the responses of most (beta-endorphin, ACTH,
prolactin, catecholamines), but not all (growth hormone, cortisol), hormones to
hypoglycemia were exaggerated. The remarkable increase in ACTH and beta-endorphin
release was not accompanied by concomitant increase of plasma cortisol response.
The sympathetic-adrenomedullary system was significantly activated, which was
manifested particularly by enhanced norepinephrine release. Growth hormone
response to hypoglycemia was not modified, while that of prolactin was enhanced.
Thus during evaluation of neuroendocrine function under clinical conditions,
changes in ambient and body temperature should not be underestimated.
PMID- 9766254
TI - Growth hormone secretion in Prader-Willi syndrome.
AB - Prader-Willi Syndrome (PWS) is a multisystem defect characterized by obesity,
hypogenitalism and short stature for genetic background. Low GH serum levels have
been found in patients with PWS and were related to a hypothalamic-pituitary
dysfunction. We studied spontaneous nocturnal GH secretion and GH-response to
provocative tests in five patients affected by PWS. We observed in three of them
(Group A) abnormally low GH and IGF-1 serum levels. In the other two patients
(Group B) GH secretion and IGF-1 serum levels were normal. In all patients no
thyroid dysfunction was observed. These data might suggest the presence of two
different subgroups of patients affected by PWS, from an endocrinological point
of view. An abnormally low GH secretion would be evident only in a subgroup of
patients, which appears to be normal in the remaining patients. This casistic is
small in number, but if our data will be confirmed by more extensive studies it
may be possible to identify a specific population of PWS patients who could
benefit from recombinant GH-therapy.
PMID- 9766255
TI - Effect of low-dosage recombinant human growth hormone therapy on pulmonary
function in hypopituitary patients with adult-onset growth hormone deficiency.
AB - An impairment of the pulmonary function has been described in adult patients with
childhood-onset growth hormone deficiency (GHD). We examined forced vital
capacity (FVC), forced expiratory volume (FEV1), total lung capacity (TLC),
functional residual capacity (FRC), residual volume (VR) and the index of
inspiratory strength, middle tidal volume and tidal inspiratory time ratio
(TV/I), in 29 patients with adult-onset GHD. Data were compared with those
obtained in 46 healthy control subjects. Only the FEV1/FVC ratio was
statistically different (p = 0.04) between the two groups of subjects. In a group
of 15 GHD patients low dosages (0.5-1 IU/day s.c., bedtime) of recombinant human
GH (rh-GH; n. = 8 subjects) or placebo (n. = 7) were given at random for a 6
month period. A significant increase in IGF-I levels was noted in the rh-GH
treated group (p = 0.04) but not in the placebo group. After the 6-month period
no statistically significant changes in pulmonary function were found between the
rh-GH-treated and placebo-treated GHD patients. This study shows that adult-onset
GHD patients suffer from minimal impairment of pulmonary function. Low rh-GH
dosages able to induce an increase in IGF-I levels do not improve pulmonary
function. The effect of rh-GH on respiratory muscle strength could be related to
the age at which GHD diagnosis is made, or induced only by high rh-GH dosages
given for a long time.
PMID- 9766256
TI - Endocrinological aspects of Langerhans cell histiocytosis complicated with
diabetes insipidus.
AB - Langerhans cell histiocytosis (LCH) is a rare disorder and may be complicated
with hypopituitarism and diabetes insipidus (DI) due to invasion of the
hypothalamic-pituitary area. In this study, 10 patients with complete (4) and
partial (6) type central DI were found among 125 LCH patients in our hospital
records. The water deprivation test, followed by the pitressin test, was
performed to confirm DI. Hypothalamic-pituitary endocrine function tests were
carried out on these 10 patients at the initial diagnosis and during follow-up.
All patients revealed growth hormone insufficiency in the insulin hypoglycemic
tolerance test. Four patients had impairment of cortisol secretion, demonstrated
by insulin hypoglycemic stimulating test results. Two patients had poor response
in the thyrotropin releasing hormone stimulating test. Two patients had only
partial responses in the luteinizing hormone releasing hormone test. Four
patients had hyperprolactinemia. All patients underwent surgical treatment
followed by chemotherapy and/or radiotherapy. One patient completely recovered
from the endocrine disorder, 3 patients required smaller doses of desmopressin,
and one patient had normal adrenal, thyroid, and gonadal function. Hypothalamic
pituitary disorders in LCH should not be neglected. Treatment of LCH can
partially or completely reverse associated endocrine disorders. Therefore,
endocrine studies and hormone replacement should be mandatory for patients with
LCH.
PMID- 9766258
TI - Growth hormone binding protein activity in obese children.
AB - We evaluated growth hormone binding protein (GHBP) activity in a group of obese
children (12 boys and 12 girls, age 3.1-14.7 years, BMI 21.1-33.3, 11 prepubertal
and 13 early pubertal) and in 26 age-matched normal weight children (14 boys and
12 girls, age 2.1-16.0 years, BMI 14.2-21.4, 18 prepubertal and 8 early
pubertal). All children were of normal stature. GHBP activity was significantly
higher in the obese (39.1 +/- 1.1%) than in the control children (28.3 +/- 1.0%,
p < 0.0001). Mean serum GHBP was not different between boys and girls or between
prepubertal and pubertal subjects. A positive correlation was found between BMI
and GHBP levels only in the normal weight children (r = 0.425, p < 0.05).
Baseline insulin concentrations in the obese children were 97.6 +/- 7.9 pmol/l
(normal values, 45.0 +/- 18.6 pmol/l), and the mean insulin AUC following OGTT in
the obese was 811.3 +/- 160.7 pmol/l (normal values, 373.1 +/- 150.1 pmol/l).
Serum GHBP activity in the obese was not correlated with baseline serum insulin
concentrations or with the insulin AUC following OGTT. In conclusion, we found
that obese children have elevated GHBP activity, and speculate that this
phenomenon may serve to compensate for their reduced GH secretion and accelerated
GH clearance.
PMID- 9766257
TI - Immunohistochemical detection of glycoprotein hormone alpha subunit in
somatoprolactinic and pure somatotroph adenomas.
AB - Glycoprotein hormone alpha subunit (alpha SU) is expressed in nearly all
thyreotroph adenomas and most gonadotrophinomas, but is less well documented in
plurisecreting adenomas. We therefore examined the immunohistochemical (IHC)
expression of alpha SU in a generally accepted model of plurisecreting adenomas
(somatoprolactinic type) by comparison to a series of pure monosecreting
somatotroph tumors. Fifty patients (32 females, 18 males) aged 15 to 68 years
with clinical and/or biological acromegaly requiring adenomectomy were studied.
Forty-five had clinical acromegaly and 5 had isolated amenorrhea and/or
galactorrhea syndromes. Forty-eight of the 49 patients who had baseline
assessments of plasma GH had a mean concentration of 5 ng/ml or more (normal
value < 5). Fifteen of the 46 patients who had baseline measurements of plasma
PRL had a prolactinemia value greater than 20 ng/ml (normal value < 20) but below
100 ng/ml, except for one patient. All the adenomas studied were positive by GH
immunohistochemistry; 21 were immunostained by an antiPRL antibody and formed the
"somatoprolactinic" (GH-PRL) group. Five of these 21 patients were male. The 12
female patients younger than 50 years had amenorrhea or galactorrhea, and one
male patient complained of impotence. Eleven patients (9 females, 2 males) in
this GH-PRL group had hyperprolactinemia. Sixteen of these GH-PRL adenomas were
immunolabeled by alpha SU antiserum. The remaining 29 adenomas, which were
immunonegative with the PRL antibody and formed the "somatotroph adenoma" (GH)
group, were more frequent in male patients (13/29; 45%) compared to GH-PRL group.
Eight amenorrhea or galactorrhea syndromes occurred among the 14 women younger
than 50 years, 3 of whom had hyperprolactinemia. Thirteen of these 29 adenomas
(45%) were immunopositive with alpha SU antibody. Compared to the GH group, the
GH-PRL group had a significant higher frequency of amenorrhea and/or galactorrhea
syndromes among women under 50 years (100% vs 57%; p < 0.01), as well as
hyperprolactinemia (55% vs 15%; p < 0.01) and positive alpha SU immunoreactivity
(76% vs 45%; p < 0.05). The frequency of extrasellar macroadenomas was not
different according to PRL or alpha SU immunoreactivity. Thus, in this series of
somatoprolactinic adenomas, alpha SU immunopositivity was slightly more frequent
than in a control group of pure somatotroph adenomas. Moreover,
hyperprolactinemia was more frequent in patients with GH-PRL adenomas, although
the size of the pure and mixed adenomas was not different. These results suggest
that hyperprolactinemia and/or alpha SU immunopositivity are more often
associated with mixed GH-PRL adenomas.
PMID- 9766259
TI - Papillary microcarcinoma of the thyroid.
AB - Papillary microcarcinoma of the thyroid has been often detected by aspiration
biopsy cytology performed with ultrasonographic guidance. Autopsy studies also
have often revealed small thyroid carcinomas, and it was concluded that most
small thyroid carcinomas should not be regarded as a clinical matter. In this
study, 112 patients with papillary microcarcinoma 10 mm or less in size treated
between 1992 and 1995 were analyzed. There were 104 females and 8 males, with a
mean age of 46.0 years. Diagnosis of papillary carcinoma was made preoperatively
in 100 of these patients (89.3%), and 77 patients underwent aspiration biopsy
cytology under ultrasound guidance. Seventy of these patients underwent modified
neck dissection, and 63.8% of these patients had lymph node metastases. The
number of lymph node metastasis increased as primary tumor size increased. There
was no clear border or clinical differences between primary tumors 10 mm or less
and tumors more than 10 mm. One patient had lymph node recurrence after surgery
and another patient had recurrent nerve palsy at the first visit. Based on these
findings, papillary microcarcinoma should be treated surgically.
PMID- 9766261
TI - Different effects of octreotide by continuous night infusion at increasing rate
or by evening injections at different times on morning hyperglycemia and growth
hormone levels in insulin-dependent diabetic patients.
AB - The effect of octreotide on morning hyperglycemia and GH levels was evaluated in
eight insulin-dependent diabetic patients. Octreotide (50 mcg) was administered
through subcutaneous injections at different hours (20:00, 22:00 and 24:00 h) or
through continuous subcutaneous night infusion from midnight to 08:00 at
increasing rate between 03:00 and 08:00 h. After octreotide injection at midnight
we noticed a sharp decrease of both glycemia (p < 0.005) and GH (p < 0.05) at
04:00 h, but not at 08:00 h. Only the night continuous infusion at increasing
rate was able to reduce glycemia and GH at 04:00 and at 08:00 h (p < 0.001 and p
< 0.01 respectively). The injections of octreotide at 20:00 and 22:00 h lowered
GH values at 24:00 h (p < 0.01 and p < 0.05 vs insulin alone) but did not show
any significant effect on blood glucose levels and GH at 04:00 and 08:00 h. In
conclusion, only the continuous subcutaneous night infusion of octreotide at
increasing rate during the last hours of the night was able to reduce
simultaneously morning hyperglycemia and GH levels in insulin-dependent diabetic
patients, whereas evening subcutaneous injections at different times did not show
any appreciable effect.
PMID- 9766262
TI - The use of colour slides in the assessment of changes in soft-tissue involvement
in Graves' ophthalmopathy.
AB - There is a need for more reliable and validated methods to assess the eye changes
in Graves' disease. Such measurements are now available for the assessment of
proptosis, eye muscle dysfunction, and optic nerve involvement. However, no
validated objective measurement exists for NO SPECS class II signs. The present
study compares the use of colour slides with clinical grading for assessing soft
tissue involvement. Forty-three patients were treated with retrobulbar
irradiation. Pre-treatment, and 6 months post-treatment the severity of class II
signs was graded from 0 to grade c in two ways; 1) Clinically, by two
independent, experienced observers, who recorded their scores on the same day; 2)
From colour slides, taken at the same visits, which were graded afterwards in one
session independently by the same observers. Inter-observer agreement about
clinical grading was low (Kappa 0.32), and was not improved by using the slides
(Kappa 0.35). However, by using the clinical scores, the observers disagreed on
treatment outcome in 21/43 patients (49%), whereas using the slides disagreement
occurred in only 6/43 (14%, p < 0.01). It is concluded that the grading of soft
tissue involvement is highly subjective. However, the use of colour slides does
provide a more reliable way to assess a treatment effect and should be used in
clinical trials.
PMID- 9766260
TI - Effect of acute corticotropin releasing factor on pituitary-adrenocortical
responsiveness in elderly women and men.
AB - Aging is related to critical changes of the hypothalamo-pituitary-adrenal
function. A decline in serum DHEA levels has been demonstrated in healthy elderly
subjects, while ACTH and cortisol concentrations remain at normal values. The
purpose of the present study was to investigate the effect of aging on pituitary
adrenal responsiveness to hCRF in subjects of both sexes. A group of 12
physically and mentally healthy elderly subjects and a group of 12 young controls
of both sexes have been selected. Blood samples were collected before and after
i.v. bolus injection of hCRF; ACTH, cortisol and DHEA levels were then determined
by RIA. Basal ACTH and cortisol levels did not result statistically different
between controls and elderly subjects, while DHEA showed a clear and significant
age-related decrease (p < 0.01). Following the hCRF injection, the responses of
ACTH, cortisol and DHEA in aged subjects were higher than in young controls; ACTH
(p < 0.03) and cortisol (p < 0.01) were higher in aged women than in men. The
present study demonstrated that aging is associated with an increased
responsiveness of ACTH, cortisol and DHEA to exogenous hCRF supply. A
hyperactivation of the pituitary-adrenal secretory activity may explain the age
related of the same axis. Gender probably has a significant influence on basal
and stimulated hormonal secretion. In conclusion, hCRF test may become a useful
clinical tool in establishing a neuroendocrine correlation with central
disturbances associated to aging.
PMID- 9766263
TI - Hypoglycemia unawareness in a patient with dumping syndrome: report of a case.
AB - We report the case of a 49-yr-old man affected by coma and hypoglycemia
unawareness following repetitive hypoglycemic episodes due to dumping syndrome.
The dumping syndrome, which was due to partial gastrectomy and vagotomy performed
for recurrent peptic ulcer, was responsible for reactive hyperinsulinemia as
demonstrated by an oral glucose tolerance test. While the glucose
counterregulatory hormones were all normally sensitive to specific stimulation
tests, insulin-induced hypoglycemia failed to induce an adequate
counterregulatory response, causing no response in plasma norepinephrine, a
slight and short increase in plasma cortisol, ACTH and glucagon and an
insufficient increase in plasma epinephrine and GH. This case demonstrates that
hypoglycemia unawareness has to be taken into account not only in patients
affected by IDDM or insulinoma but also in any case of reactive hypoglycemia.
PMID- 9766264
TI - Ablative or non-ablative therapy for Graves' hyperthyroidism in patients with
ophthalmopathy?
PMID- 9766265
TI - Ablative or non-ablative therapy for Graves' hyperthyroidism in patients with
ophthalmopathy?
AB - In our view there are no properly controlled trials which support a beneficial
effect on ophthalmopathy from surgical or radioiodine-based deliberate ablation
for hyperthyroidism. The theoretical basis for this approach can be questioned
and we still know too little about the pathogenesis of ophthalmopathy to draw any
firm conclusions about the likely effects of ablation. There are established
risks with ablation. Like the majority of European thyroidologists, we prefer
antithyroid drugs for the initial treatment of hyperthyroidism complicated by
Graves' ophthalmopathy and individualise treatment for recurrent hyperthyroidism
based on the patient's preference, but do not recommend ablation routinely in
presence of eye signs.
PMID- 9766267
TI - Neuroendoscopy. Personal experience, indications and limits.
AB - The authors report a series of 40 patients treated by endoscopic neurosurgery. It
includes 31 cases of obstructive hydrocephalus, 4 paraventricular or
intraventricular CSF cysts, 3 cases of multiloculated hydrocephalus, one
suprasellar arachnoid cyst and one cystic astrocytoma with mural tumor nodule.
Third ventriculostomy is the most frequent indication of the endoscopic
neurosurgery, which is very useful also for performing fenestration of CSF cysts
and multiloculated hydrocephalus. The surgical endoscopic techniques in the
different above mentioned pathologies are exposed. The criteria for patient
selection, the clinical results and the postoperative radiological findings, that
confirm the patency of the fenestration, are discussed.
PMID- 9766268
TI - Nerve regeneration over a 20-mm gap through a nerve conduit containing blood
vessels in rats: the influence of interstump distance on nerve regeneration.
AB - BACKGROUND: The present study was conducted in rats to investigate whether a tube
with additional intrachamber vascularization could permit axons to extend over a
distance greater than 10 mm, which appears to be the maximum axon regeneration
distance for rat sciatic nerve axons through a normal empty tube. METHODS: A
sural vessel-containing tube (VCT) was designed and interposed between transected
sciatic nerve stumps in the thigh, leaving a 20-mm interneural gap. RESULTS:
Twelve weeks after tubulation, six out of nine rats showed successful nerve
regeneration and re-innervation of the soleus muscle using the VCT. At 24 weeks,
intrachamber nerve regeneration and re-innervation of the soleus and pedal
adductor muscles were electrophysiologically and histologically confirmed in all
rats. However, no neural tissue was observed within any ligated sural vessel
containing tube (LVCT) or empty unmodified tube (ET) with a 20-mm interneural
gap. When nerves regenerated in the VCT with a 20-mm gap were compared with those
regenerated in a VCT with a 10-mm gap 12 and 24 weeks after surgery, the results
produced by the VCT with a 20-mm gap were inferior to those after use of the VCT
with a 10-mm gap, except for motor nerve conduction velocity at 24 weeks.
CONCLUSIONS: The value recovered to almost identical levels (about 50-60% normal)
in both groups.
PMID- 9766269
TI - High-dose heparin plus warfarin administration in non-traumatic dural sinuses
thrombosis. A clinical and neuroradiological study.
AB - BACKGROUND: The management of intracranial dural sinuses thrombosis is still
controversial and uncertain. The authors report the cases of 7 patients with non
traumatic thrombosis of the dural sinuses and describe the most important
radiographic findings, the indication, effectiveness of antithrombotic therapy,
and outcome. METHODS: A retrospective review was conducted of 7 cases of dural
sinus thrombosis admitted, between 1994 and 1996, to our division. All patients
underwent full anticoagulation therapy. Heparin was administered, using a dose of
25,000 units/day for two weeks; warfarin was given using a dose of 5 mg twice
daily. Treatment course was followed by maintenance treatment with a single
administration of 5 mg/day of warfarin. All patients were submitted to close
titration and coagulation profile monitoring. RESULTS: In 4 cases Magnetic
Resonance Imaging-Angiography (Angio-MRI) was performed for following up the
recanalization of the sinuses, resulting a persistent no patency of the dural
sinuses. Three patients underwent contrast-enhanced CT scan, demonstrated an
"empty delta sign" in the sagittal sinus, confirming no recanalization.
Nevertheless, six patients had have a good quality recovery, and one patient a
moderate disability. DISCUSSION: Cerebral venous sinus thrombosis is an uncommon
cause of cerebral infarction, and may be mistaken, unless specifically sought.
The natural history of the disease is highly variable, with a mortality rates
range from 10% to 20%. At present, in our opinion, the venous phase of Angio-MRI
is the definitive examination, and a gold standard for diagnosis of dural sinus
thrombosis. In our cases, antithrombotic therapy has been found to be a safe and
effective treatment, despite contrast-CT scans and Angio-MRI showed no
recanalization of the sinuses, in all patients.
PMID- 9766266
TI - Role of GnRH drive in the pathophysiology of polycystic ovary syndrome.
AB - Polycystic ovary syndrome may result from multiple mechanisms, but full
expression of the PCO syndrome with hyperandrogenic anovulation depends upon
sustained LH drive and relative FSH deficiency. We have described possible
intrinsic and extrinsic factors capable of modifying the hypothalamic-pituitary
ovarian axis. Available evidence suggests the presence of an intrinsic alteration
in GnRH-LH drive. The long-term natural history of HAA is variable and depends on
several factors including obesity, aberrations in insulin action, intrinsic
ovarian function, and end-organ responsiveness to androgens. Figure 1 presents a
conceptualization of the pathogenesis of PCOS diagramming the multiple modulators
of its expression. Long-term suppression of androgens when fertility is not
desired should modify the full expression of the PCO syndrome. It is important to
appreciate that therapy with oral contraceptive agents has few drawbacks and many
immediate and potential long-term benefits for women with HAA. This therapy may
be of greatest benefit when started in adolescence prior to the progression of
obesity, hirsutism, and thecal-stromal hyperplasia. Women with HAA represent a
large subgroup of patients who require individualization of their health care
with sensitivity to issues surrounding anovulation, obesity, hirsutism, and
infertility.
PMID- 9766270
TI - CBF change with aging in moyamoya disease.
AB - The change of cerebral blood flow (CBF) with aging was analyzed in 9 cases of
moyamoya disease whose age ranged from 16 years old to 58 years old. CBF
decreased more prominently in the various lobes with aging than control subjects
and the decrement was more rapid in the affected side than in the non-affected
side. CBF was thought to decrease with the hemorrhagic attack and the
accompanying neurological deterioration. However the gradually-deteriorating
brain damages caused by the chronic hypoperfusion also might be engaged in this
CBF decrement.
PMID- 9766271
TI - Choroid plexus papillomas of the posterior fossa: extraventricular extension,
intraventricular and primary extraventricular location. Report of four cases.
AB - Four cases of Choroid Plexus Papilloma (CPP) of the posterior fossa are
presented. Two cases had extraventricular extension from the fourth ventricle to
the Cerebellopontine Angle (CPA) through the foramen of Luschka, in one the CPP
was located primarily in the CPA and the fourth case was only in the fourth
ventricle. CPP are rare tumours of the Central Nervous System and primary
extraventricular location is extremely rare. We know that primary location in the
extraventricular and intraventricular regions and extraventricular extension have
different pathological mechanisms. The main purpose of this paper is to discuss
and review some possible explanations for these mechanisms.
PMID- 9766273
TI - Peduncular hallucinosis following a transoral odontoidectomy for cranio-vertebral
junction malformation. A case report.
AB - This is a case report of a sixty-two years old man suffering from a cranio
vertebral malformation whose dens epistrophei was removed through a transoral
approach. During the postoperative course, he experienced a transient peduncular
hallucinosis probably caused by surgical trauma on his brainstem. The possible
physiopathological, etiopathological, clinical, and therapeutic aspects of this
rare phenomenon are discussed.
PMID- 9766272
TI - Association between an aneurysm of the anterior inferior cerebral artery and an
arteriovenous malformation fed by the same artery.
AB - An unusual case of distal aneurysm of the anterior inferior cerebellar artery
(AICA) associated with a cerebellar arteriovenous malformation in a 35 year-old
woman is reported. The clinical presentation was a subarachnoid hemorrhage, that
is the sudden onset of headache while she was driving her car. In the following
days the patient experienced a cerebellopontine angle syndrome: unsteadiness,
tinnitus and hearing loss in her left ear, along with drop episodes. All symptoms
disappeared in about a week. She consulted a neurosurgeon only a month later. On
the day of admission in the Neurosurgical Department of Residence du Parc Clinic
her neurological status was normal. Neuroradiological investigations showed the
association between the two distal AICA malformations. At surgery it was possible
either to clip the aneurysm or to remove the AVM. The origin of the hemorrhage
has not been clearly identified. The patient had an uneventful recovery and
returned to her job three months later. The aneurysm was located on the same
artery that supplied the AVM. This association is rare at the AICA level. The
possible development of the aneurysm induced by increase in flow through the AVM
is discussed in the light of Literature data.
PMID- 9766274
TI - A possible sequela of transoral approach to the upper cervical spine.
Velopharyngeal incompetence.
AB - The authors describe a case of velopharyngeal incompetence (VPI), as a
consequence to the neurosurgical treatment for a complex malformation of the
cranio-spinal junction. A 61-year-old woman underwent a transoral-transvelar
surgical approach for odontoid resection. One month later surgical fixation of
the posterior spine with autologous iliac bone graft was performed. Following
these operations the patient presented a marked alteration of speech
intellegibility due to hypernasal voice resonance and through incapability to
articulate the oral phonemes correctly. She also complained of nasal
regurgitation of fluids and solids while swallowing. She underwent a clinical
phoniatric assessment of voice and speech. Videonasopharyngoscopy allowed us to
inspect the velopharyngeal sphincter and to show clearly the type and morphology
of its closure defect. Correction of VPI was achieved by means of a
velopharyngoplasty (pharyngeal flap), in spite of technical difficulties due to
local scarring and to a problematic exposure of the surgical field.
PMID- 9766275
TI - Intracerebral schwannoma. Case report.
AB - A case of intraparenchymal schwannoma is presented. A 61-year-old woman, with
stigmata of von Recklinghausen's neurofibromatosis (NF-2), presented with a
history of weakness of the right lower limb for 2 months. She was investigated by
MR which showed a circular mass with a maximum diameter of 5 cm in the right
parieto-occipital lobe. The tumor was removed in toto via a left parieto
occipital craniotomy. The patient was discharged two weeks after the operation
and remains well now 2 years later. The clinical and neuroradiological findings
of reported intraparenchymal schwannomas, including the case reported here, are
discussed.
PMID- 9766276
TI - A fatal acute subdural hematoma occurring after evacuation of "contralateral"
chronic subdural hematoma.
AB - Although chronic subdural hematomas (SDHs) are bilateral in about 20% of the
cases, an acute SDH in one side associated with chronic SDH in "contralateral"
side is an extremely rare and devastating condition. In this report, a case of
"contralateral" acute SDH occurring after evacuation of chronic SDH in one side
is presented. The clinical history, complaints, neurological and
neuroradiological findings, and pathophysiological mechanisms of this uncommon
entity are discussed and related literature is reviewed.
PMID- 9766277
TI - Revisiting the high-tech/high-touch dilemma.
PMID- 9766278
TI - The use of haloperidol to treat nausea.
PMID- 9766279
TI - Keeping surgical drains open.
PMID- 9766280
TI - Lymphedema and exercise.
PMID- 9766282
TI - Recognizing and treating dysfunctional grief.
PMID- 9766281
TI - Fentanyl for dyspnea relief.
PMID- 9766283
TI - Care of the patient with perineal skin injury.
PMID- 9766284
TI - Apheresis unit preparation for patients receiving peripheral blood stem cells.
PMID- 9766285
TI - Additional tips from members. Promoting environmentally responsible health care.
PMID- 9766286
TI - DNA testing for cancer predisposition.
AB - PURPOSE/OBJECTIVES: To describe and review scientific and regulatory aspects of
molecular genetic technology in the context of DNA testing for cancer
predisposition. DATA SOURCES: Published professional articles, texts, and
proceedings; commercial testing companies; computerized data bases; and the World
Wide Web. DATA SYNTHESIS: This article reviews the basic molecular biology (e.g.,
DNA, genes, chromosomes, DNA mutations) that is the foundation for indirect and
direct methods of DNA testing for cancer predisposition. Key issues in DNA
testing include who should be tested, provision of testing, and regulatory
concerns. Benefits and problems of testing contribute to its current
controversial status. CONCLUSIONS: Understanding the mechanisms of DNA testing
for cancer requires knowledge of basic molecular biology. Family history of the
cancer in question is a key indicator for predisposition testing. Accessing
information regarding research-based testing is challenging. DNA testing for
cancer predisposition is not a perfect test, as exemplified by issues related to
test regulation and sensitivity. IMPLICATIONS FOR NURSING PRACTICE: Basic
knowledge of DNA testing for cancer predisposition will help nurses to (a) have a
better understanding of the indications for and ramifications of testing, (b)
provide information about testing to patients and the lay public, (c) counsel
patients and families at high risk for inherited cancers more effectively, and
(d) interpret DNA test results.
PMID- 9766287
TI - End-of-life confusion in patients with cancer.
AB - PURPOSE/OBJECTIVES: To review the literature on confusion at the end of life,
provide accurate definitional and defining characteristics of confusion, and
outline nursing strategies for its resolution. DATA SOURCES: Published articles,
computerized databases, book chapters, reference lists from chapters and journal
articles. DATA SYNTHESIS: As a major component of symptom distress in terminal
care, confusion has not been defined clearly and therefore has not benefited from
rigorous assessment and study as have other end-of-life symptoms. CONCLUSIONS:
Increased knowledge about confusion that occurs in patients with widely
metastatic cancer will assist in accurate symptom identification, early
recognition, and timely management to reduce cognitive symptom distress at the
end of life. Improved symptom resolution also can benefit family coping during
terminal care. IMPLICATIONS FOR NURSING PRACTICE: Oncology nurses can devise
management protocols for confused patients that include screening criteria,
pharmacologic interventions, environmental support, and prophylactic safety
measures.
PMID- 9766289
TI - Leptomeningeal metastasis: pathophysiology, treatment, and nursing management.
AB - PURPOSE/OBJECTIVES: To review the pathophysiology, diagnosis, and clinical
treatment of leptomeningeal metastasis. DATA SOURCES: Published articles,
abstracts, and book chapters. DATA SYNTHESIS: Leptomeningeal metastasis is an
increasingly seen complication of cancer. Treatment is intensive and may increase
survival from four to five weeks without treatment to an average of six months.
Clinical management and treatment of these patients is complex and best
accomplished by a multi-disciplinary healthcare team. CONCLUSIONS: Information
regarding the anatomy, pathophysiology, treatment, and treatment complications
can facilitate the care of patients with leptomeningeal metastasis. IMPLICATIONS
FOR NURSING PRACTICE: Nursing interventions should focus on patient and family
education about the disease process, side-effects of treatment, and early
identification of disease progression.
PMID- 9766288
TI - Measuring the information needs of husbands of women with breast cancer: validity
and reliability of the Family Inventory of Needs--husbands.
AB - PURPOSE/OBJECTIVES: A two-phase study was undertaken to test the Family Inventory
of Needs--Husbands (FIN-H), a tool designed to measure the information needs of
husbands of women with breast cancer and the extent to which these needs are met.
DESIGN: Methodologic survey. SAMPLES: Phase I: a panel of 6 husbands; phase II:
84 husbands of women with breast cancer. METHODS: Panel of expert ratings
followed by pilot test of the two-part survey. FINDINGS: In phase I, husbands
assessed the FIN-H for clarity, internal consistency, and content validity. All
preset criteria were met. In phase II, internal consistency, test-retest
reliability, and internal validity were assessed. Internal consistency estimates
as measured by Cronbach's standardized alpha coefficients were 0.91 and 0.93.
Test-retest correlations were 0.82 and 0.76 (p = 0.0001). Exploratory factor
analysis suggested that the FIN-H consists of five factors. CONCLUSIONS: Initial
results suggest that the FIN-H is reliable and valid. Further testing is needed
to confirm these results. IMPLICATIONS FOR NURSING PRACTICE: Before nurses can
address the information needs of husbands of women with breast cancer, use of a
reliable and valid assessment tool is recommended.
PMID- 9766291
TI - Family-level services in oncology nursing: facts, fallacies, and realities
revisited.
PMID- 9766290
TI - Effects of dialogue and therapeutic touch on preoperative and postoperative
experiences of breast cancer surgery: an exploratory study.
AB - PURPOSE/OBJECTIVES: To obtain preliminary data and determine the feasibility of a
large-scale experimental study to test the efficacy of the Rogerian Science of
Unitary Human Beings-based intervention of dialogue and therapeutic touch (TT) on
pre- and postoperative anxiety and mood and postoperative pain from breast cancer
surgery. DESIGN: Experimental. SETTING: Mid-Atlantic region; ambulatory. SAMPLE:
29 Caucasian and 2 African American English-speaking women with positive breast
cancer biopsy (experimental, n = 14; control, n = 17), ranging in age from 31-84
years old (F = 55.6). METHODS: Treatments administered in subjects' homes within
seven days prior to surgery and 24 hours after hospital discharge. Experimental
treatment consisted of 10 minutes of TT and 20 minutes of dialogue. Control
treatment consisted of 10 minutes of quiet time and 20 minutes of dialogue. Data
(Spielberger State-Trait Anxiety Inventory. Affects Balance Scale, and Visual
Analog Scale-Pain) were collected at the conclusion of each home visit. MAIN
RESEARCH VARIABLES: Anxiety, mood, and pain. FINDINGS: The experimental group had
lower preoperative state anxiety than the control groups (p = 0.008). No
difference was found for preoperative mood. No differences were found for any
postoperative measure. CONCLUSIONS: A large-scale study of dialogue and TT would
require changes in design and recruitment strategies. IMPLICATIONS FOR NURSING
PRACTICE: Nurses may provide more comprehensive care by incorporating dialogue
and TT or quiet time into their pre- and postoperative care. Additional research,
however, is recommended to determine the differential effects of dialogue, TT,
and quiet time on women's experiences with breast cancer prior to incorporating
these noninvasive modalities into clinical practice.
PMID- 9766292
TI - Establishing mechanisms to conduct multi-institutional research--fatigue in
patients with cancer: an exercise intervention.
AB - PURPOSES/OBJECTIVES: To describe the process of establishing a multi
institutional interdisciplinary team of oncology researchers and conducting a
pilot study of an exercise intervention for fatigue. DATA SOURCES: Project
meeting minutes and records, research team members' logs, subjects' research
records, the research study proposal, and team members' individual and collective
shared experiences. DATA SYNTHESIS: Site investigators established research teams
at five academic medical centers. Fifty subjects were enrolled in the study and
tested during their cancer treatment. Study methods, including instrumentation,
were evaluated carefully and revised. CONCLUSIONS: The multi-institutional
network of researchers is an effective and efficient model for testing an
intervention to manage fatigue during cancer treatment. IMPLICATIONS FOR NURSING
PRACTICE: Exercise is a feasible and potentially beneficial intervention to
combat distressing cancer treatment-related fatigue. A pilot study is essential
to determine the best methods for conducting a clinical trial and to develop the
teams of researchers necessary for such a project.
PMID- 9766293
TI - Planning and conducting a multi-institutional project on fatigue.
AB - PURPOSE/OBJECTIVES: To describe the process used in proposal development and
study implementation for a complex multisite project on cancer treatment-related
fatigue (CRF), identify strategies used to manage the project, and provide
recommendations for teams planning multisite research. DATA SOURCES: Information
derived from project team meeting records, correspondence, proposals, and
personal recollection. DATA SYNTHESIS: The project was built on preexisting
relationships among the three site investigators who then built a team including
faculty, research coordinators, staff nurses, and students. Study sites had a
range of organizational models, and the proposal was designed to capitalize on
the organizational and resource strengths of each setting. Three team members
drawn from outside oncology nursing provided expertise in measurement and
experience with fatigue in other populations. Planning meetings were critical to
the success of the project. Conference calls, fax technology, and electronic mail
were used for communication. Flexibility was important in managing crises and
shifting responsibility for specific components of the work. The team documented
and evaluated the process used for multisite research, completed a major
instrumentation study, and developed a cognitive-behavioral intervention for CRF.
CONCLUSIONS: Accomplishments during the one-year planning grant exceeded initial
expectations. The process of conducting multisite research is complex, especially
when the starting point is a planning grant with specific research protocols to
be developed and implemented over one year. Explicit planning for decision-making
processes to be used throughout the project, acknowledging the differences among
the study settings and planning the protocols to capitalize upon those
differences, and recruiting a strong research team that included a member with
planning grant and team-building expertise were essential elements for success.
IMPLICATIONS FOR NURSING PRACTICE: Specific recommendations for others planning
multisite research are related to team-building, team membership, communication,
behavioral norms, role flexibility, resources, feedback, problem management, and
shared recognition.
PMID- 9766294
TI - Developing a team for multicultural, multi-institutional research on fatigue and
quality of life.
AB - PURPOSE/OBJECTIVES: To describe the process of establishing a multisite team to
conduct research with a multicultural focus on fatigue. DATA SOURCES: Articles,
book chapters, personal experience. DATA SYNTHESIS: Teamwork facilitated
development of a productive professional working group, sharing of resources, and
data collection culminating in a research proposal for studying cancer-related
fatigue in a multicultural population. CONCLUSIONS: Establishing a common goal by
investing time, committing to the process, and establishing trust was the secret
to effective team functioning. IMPLICATIONS FOR NURSING PRACTICE: The prospect of
multi-institutional collaboration has implications for oncology nurses in the
areas of research and practice. Goals that could not be achieved easily in the
setting of a single institution are reached more easily with multisite
collaboration and teamwork.
PMID- 9766295
TI - Distress, symptom distress, and immune function in women with suspected breast
cancer.
AB - PURPOSE/OBJECTIVES: To investigate distress and its association with immune
function among women with suspected breast cancer. DESIGN: Prospective,
descriptive, correlational study. SETTING: An outpatient breast clinic at a
tertiary urban hospital. SAMPLE: A convenience sample of women who had either a
fine needle aspiration or open breast biopsy for a suspicion of breast cancer.
Thirty-five women comprised the study sample, 6 with malignant and 29 with benign
tumors. METHODS: Data were collected at three points in time. The first time (T1)
was after the physician visit when the need for breast biopsy was ascertained.
The second time (T2) was 7-10 days postbiopsy, and the third time (T3) was 7-10
days after T2. At T1, T2, and T3, participants filled out the Brief Symptom
Inventory (a measure of psychological distress) and the Adapted Symptom Distress
Scale (a measure of symptom distress) and provided a blood sample. Demographic
data also were collected at T1. Immune function was measured by serum cytokine
levels of transforming growth factor beta (TGF beta) and tumor necrosis factor
alpha (TNF alpha). MAIN RESEARCH VARIABLES: Psychological distress, symptom
distress, and immune function. FINDINGS: Psychological distress scores were
moderate to high. Symptom distress was either nonexistent or slight. Significant
correlations between psychological distress and symptom distress were found at T2
and T3. At T2, significant relationships between psychological distress and TNF
alpha and between symptom occurrence and TNF alpha were found. Psychological and
symptom distress scores were significantly different between women with malignant
versus benign tumors at all three times. No differences in cytokine levels were
found between the groups. CONCLUSIONS: These results suggest the strong effect
that the diagnostic process has on psychological distress and its potential
effects on immune functioning. Distress was significantly greater for women with
malignant disease; however, women with benign disease continued to have elevated
levels of distress. IMPLICATIONS FOR NURSING PRACTICE: Nurses should be aware of
the extremely stressful nature of the diagnostic phase and should continue to
provide support, knowing that this distress continues throughout this phase,
particularly for women diagnosed with malignancy.
PMID- 9766296
TI - Clinical care for patients receiving autologous hematopoietic stem cell
transplantation in the home setting.
AB - PURPOSE/OBJECTIVES: To undertake a pilot study of autologous hematopoietic stem
cell transplantation (HSCT) in the patient's home to improve satisfaction of
care, reduce financial costs, and relieve pressure on inpatient accommodation.
DESIGN: Descriptive, cross-sectional, qualitative. SETTING: Patients' homes
within the metropolitan area of Perth, Australia. SAMPLE: 25 Caucasian adults
with recurrent multiple myeloma, non-Hodgkin's lymphoma, or Hodgkin's disease
requiring autologous HSCT. METHODS: A program was developed to use the bone
marrow transplant team from a major tertiary hospital to permit home visiting,
treatment with cytotoxic chemotherapy at home, treatment of complications at
home, and an integrated home/hospital caring facility to expedite hospital
admission if complications developed. FINDINGS: The program was practical to
administer, improved overall patient satisfaction, and was significantly less
costly than inpatient transplantation. Fifteen patients (60%) of the total study
group of 25 required hospital admission for a median of five days (range 1-13
days) for management of complications, predominantly febrile neutropenia.
Nineteen (76%) of the 25 patients received i.v. antibiotic therapy at home during
the period of neutropenia. Two patients died of transplant-related complications-
one from respiratory syncytial virus infection and one from veno-occlusive
disease of the liver. These complications were not attributable to the home
setting. IMPLICATIONS FOR NURSING PRACTICE: This program increased the
responsibility and sense of autonomy of advanced practice nurses and developed
their counseling skills as well as their ability to participate more actively in
the decision-making process of those involved. MAIN RESEARCH VARIABLES:
Participation in the home transplant program, patient satisfaction, nursing
development, and cost-effectiveness of the program.
PMID- 9766297
TI - Assessing master's programs in advanced practice oncology nursing.
PMID- 9766298
TI - Craniocerebral trauma: protection and retrieval of the neuronal population after
injury.
AB - OBJECTIVE: To review the consequences of mechanical injury to the brain with an
emphasis on factors that may explain the variability of outcomes and how this
might be influenced. METHODS: Information regarding the pathophysiology of
traumatic brain damage contained in original scientific reports and in review
articles published in recent years was reviewed from the perspective of a
clinical neurosurgeon and a neuropathologist, each with major research interests
in traumatic brain damage. The information was compiled on the basis of the
knowledge of and personal selection of articles that were identified through
selective literature searches and current awareness profiles. A systematic
literature review was not conducted. RESULTS: Mechanical input affects neuronal
and vascular elements and is translated into biological effects on the brain
through a complex series of interacting cellular and molecular events. Whether
these lead to permanent structural damage or to resolution and recovery is
determined by the balance between processes that, on the one hand, mediate the
effects of initial injury and subsequent secondary insults and, on the other, are
manifestations of the brain's protective, reparative response. Experimental and
clinical research has identified opportunities for altering the balance in a way
that might promote recovery, but data demonstrating that this can lead to
substantial clinical benefit are lacking. Recent evidence of genetically
determined, individual susceptibility to the effects of injury may explain some
of the puzzling variability in outcome after apparently similar insults and may
also provide new opportunities for treatment. CONCLUSION: The understanding of
traumatic brain damage that is being gained from recent research is widening and
broadening perspectives from the traditional focus on mechanical, vascular, and
metabolic effects to encompass wider, neurobiological issues, drawn from the
fields of neurodevelopment, neuroplasticity, neurodegeneration, and
neurogenetics. Neurotrauma is a fascinating area of neuroscience research, with
promise for the translation of knowledge to improved clinical management and
outcome.
PMID- 9766300
TI - Intraoperative brain shift and deformation: a quantitative analysis of cortical
displacement in 28 cases.
AB - OBJECTIVE: A quantitative analysis of intraoperative cortical shift and
deformation was performed to gain a better understanding of the nature and extent
of this problem and the resultant loss of spatial accuracy in surgical procedures
coregistered to preoperative imaging studies. METHODS: Three-dimensional feature
tracking and two-dimensional image analysis of the cortical surface were used to
quantify the observed motion. Data acquisition was facilitated by a ceiling
mounted robotic platform, which provided a number of precision tracking
capabilities. The patient's head position and the size and orientation of the
craniotomy were recorded at the start of surgery. Error analysis demonstrated
that the surface displacement measuring methodology was accurate to 1 to 2 mm.
Statistical tests were performed to examine correlations between the amount of
displacement and the type of surgery, the nature of the cranial opening, the
region of the brain involved, the duration of surgery, and the degree of
invasiveness. RESULTS: The results showed that a displacement of an average of 1
cm occurred, with the dominant directional component being associated with
gravity. The mean displacement was determined to be independent of the size and
orientation of the cranial opening. CONCLUSION: These data suggest that loss of
spatial registration with preoperative images is gravity-dominated and of
sufficient extent that attention to errors resulting from misregistration during
the course of surgery is warranted.
PMID- 9766299
TI - Intraoperative magnetic resonance imaging with the magnetom open scanner:
concepts, neurosurgical indications, and procedures: a preliminary report.
AB - OBJECTIVE: Intraoperative magnetic resonance imaging (MRI) is now available with
the General Electric MRI system for dedicated intraoperative use. Alternatively,
non-dedicated MRI systems require fewer specific adaptations of instrumentation
and surgical techniques. In this report, clinical experiences with such a system
are presented. METHODS: All patients were surgically treated in a "twin operating
theater," consisting of a conventional operating theater with complete
neuronavigation equipment (StealthStation and MKM), which allowed surgery with
magnetically incompatible instruments, conventional instrumentation and operating
microscope, and a radiofrequency-shielded operating room designed for use with an
intraoperative MRI scanner (Magnetom Open; Siemens AG, Erlangen, Germany). The
Magnetom Open is a 0.2-T MRI scanner with a resistive magnet and specific
adaptations that are necessary to integrate the scanner into the surgical
environment. The operating theaters lie close together, and patients can be
intraoperatively transported from one room to the other. This retrospective
analysis includes 55 patients with cerebral lesions, all of whom were surgically
treated between March 1996 and September 1997. RESULTS: Thirty-one patients with
supratentorial tumors were surgically treated (with navigational guidance) in the
conventional operating room, with intraoperative MRI for resection control. For 5
of these 31 patients, intraoperative resection control revealed significant tumor
remnants, which led to further tumor resection guided by the information provided
by intraoperative MRI. Intraoperative MRI resection control was performed in 18
transsphenoidal operations. In cases with suspected tumor remnants, the surgeon
reexplored the sellar region; additional tumor tissue was removed in three of
five cases. Follow-up scans were obtained for all patients 1 week and 2 to 3
months after surgery. For 14 of the 18 patients, the images obtained
intraoperatively were comparable to those obtained after 2 to 3 months.
Intraoperative MRI was also used for six patients undergoing temporal lobe
resections for treatment of pharmacoresistant seizures. For these patients, the
extent of neocortical and mesial resection was tailored to fit the preoperative
findings of morphological and electrophysiological alterations, as well as
intraoperative electrocorticographic findings. CONCLUSION: Intraoperative MRI
with the Magnetom Open provides considerable additional information to optimize
resection during surgical treatment of supratentorial tumors, pituitary adenomas,
and epilepsy. The twin operating theater is a true alternative to a dedicated MRI
system. Additional efforts are necessary to improve patient transportation time
and instrument guidance within the scanner.
PMID- 9766301
TI - Long-term graft patency rates and clinical outcomes after revascularization for
symptomatic traumatic internal carotid artery dissection.
AB - INTRODUCTION: Surgical management of traumatic internal carotid artery (ICA)
dissection remains controversial. Therefore, the delayed outcomes and graft
patency rates of patients who underwent bypass procedures for symptomatic
traumatic ICA dissection were studied. METHODS: Between September 1989 and August
1996, 13 patients (9 male and 4 female patients; mean age, 30.6 yr) underwent 16
revascularization procedures for symptomatic traumatic ICA dissection. The
duration of clinical follow-up averaged 47.3 months (range, 12-94 mo) from the
date of diagnosis. The duration of radiographic follow-up (catheter or magnetic
resonance angiography, duplex Doppler ultrasonography) averaged 24 months (range,
12-60 mo). RESULTS: ICA dissection was caused by blunt (n = 11) or penetrating
trauma (n = 2). Associated angiographic abnormalities included seven ipsilateral
ICA occlusions, six dissecting aneurysms, two carotid-cavernous fistulae, and six
contralateral traumatic ICA dissections. Patients requiring early
revascularization (n = 6) underwent bypass procedures an average of 19.2 days
after their injuries. Medically managed patients who developed ischemia later
were revascularized a mean of 7.8 months after injury. The mean Glasgow Coma
Scale score at the time of presentation was 10 (range, scores of 6-15), and the
mean Glasgow Coma Scale score before revascularization was 14 (range, scores of 9
15). There were 14 saphenous vein ICA bypasses (8 cervical-to-petrous, 3 cervical
to-middle cerebral artery, 3 petrous-to-supraclinoid) and 2 superficial temporal
artery-to-middle cerebral artery bypasses. There was one early postoperative
graft occlusion, which responded to surgical thrombectomy. One patient with
multiple other traumatic injuries died as a result of a pulmonary embolus 12
months after revascularization. All remaining patients had Glasgow Outcome Scale
scores of 5, with patent bypass grafts confirmed during follow-up. CONCLUSION:
Revascularization for persistently symptomatic traumatic ICA dissection
eliminated ischemia and was associated with excellent long-term outcomes and
graft patency rates.
PMID- 9766302
TI - The differences in electroencephalographic changes in patients undergoing carotid
endarterectomies while under local versus general anesthesia.
AB - OBJECTIVE: This study compared the electroencephalographic (EEG) changes
occurring during carotid occlusion in 225 consecutive patients undergoing carotid
endarterectomies performed by two surgeons, one using local and the other using
general anesthesia. METHODS: A retrospective review of patients undergoing
carotid endarterectomies for carotid occlusive disease was conducted. EEG changes
associated with intraoperative ischemia (decreased amplitude, generalized
slowing, and loss of fast activity) resulting in the need for an indwelling
arterial shunt were recorded for the two anesthesia groups. To determine the
similarities or differences between the two groups, the groups were compared
regarding age, risk factors, and indications for surgery. RESULTS: Significant
EEG changes were noted in 6 of 96 patients (6.3%) in the local anesthesia group
versus 19 of 121 patients (15.7%) in the general anesthesia group. EEG changes
consisted solely of generalized slowing in the local anesthesia group, whereas a
more varied spectrum was observed in the general anesthesia group. The two groups
were similar regarding age and risk factors. Although the local anesthesia group
had more asymptomatic patients, symptomatic patients did not have a greater
incidence of EEG changes. CONCLUSION: There is a large difference in EEG changes
potentially requiring shunt placement in patients undergoing surgery while under
local (6.3%) versus general (15.7%) anesthesia. This could not be explained based
on age, risk factors, interpretation of EEG findings, or indications between the
two groups. We conclude that EEG monitoring may be insensitive and may fail to
detect ischemia in patients who are under regional anesthesia. Alternately, the
presence of general anesthetics may alter the character of the EEG findings and
increase the sensitivity of EEG monitoring to ischemic events.
PMID- 9766303
TI - Asymptomatic familial cerebral aneurysms.
AB - PURPOSE: We evaluated the prevalence and features of cerebral aneurysms in the
family members of people with asymptomatic aneurysms among 8680 participants
undergoing magnetic resonance angiography. METHODS: Of the 8680 participants, 380
had family histories of aneurysms and 8300 did not. The prevalence and features
of asymptomatic aneurysms were compared in these two subgroups. In addition, the
prevalence in all living first- or second-degree relatives was evaluated in 20
families. RESULTS: The prevalence of asymptomatic aneurysms was 7.0% (606 of 8680
participants) overall and 10.5% (40 of 380 participants) and 6.8% (566 of 8300
participants) in the subgroups with and without family histories of aneurysms,
respectively. The prevalence in the female participants with family histories of
aneurysms (12.3%, 28 of 228 participants) was higher than that in the male
participants with family histories of aneurysms (7.9%, 12 of 152 participants) (P
< 0.0001). Compared with the entire group, this subgroup more commonly showed
aneurysms situated at the junction of the internal carotid and posterior
communicating arteries (P < 0.0005) and at the middle cerebral artery (P <
0.0001). The prevalence of aneurysms in 115 members of the 20 families was 33.9%.
Although the members of 14 families with aneurysmal subarachnoid hemorrhage
showed higher prevalence of ruptured and asymptomatic aneurysms (42.1%) than did
the members of 6 families with only asymptomatic aneurysms (17.9%), the former
had very low prevalence of asymptomatic aneurysms. CONCLUSION: The prevalence of
aneurysms is significantly elevated in family members of people with asymptomatic
aneurysms. It is suggested that familial asymptomatic aneurysms are more likely
to rupture in families having members with aneurysmal subarachnoid hemorrhage
than in those without.
PMID- 9766304
TI - Too little, too late: does tirilazad mesylate reduce fatigue after subarachnoid
hemorrhage?
AB - OBJECTIVE: Trials assessing drug effectiveness for treatment of subarachnoid
hemorrhage (SAH) often use mortality rates and Glasgow Outcome Scale scores as
outcome measures. Neuropsychological and psychosocial measures might be more
sensitive to outcomes, especially for patients of better-grade status. METHODS:
Eighteen of a total of 31 patients enrolled in the New Zealand arm of the Upjohn
international, double-blind, therapeutic trial of tirilazad mesylate for women
with SAH were assessed neuropsychologically and psychosocially 3 months after
SAH. The 13 not assessed either had died or remained vegetative (9 patients), did
not speak English (1 patient), or did not consent (3 patients). The drug code was
broken after all assessments had been scored. RESULTS: Sixteen of the 31 patients
had received the drug and 15 the vehicle. There were no differences between the
two groups with respect to age, grades assessed at admission and 14 weeks after
SAH, Glasgow Outcome Scale scores assessed at 3 months, or mortality rates. In
the subgroup assessed neuropsychologically, nine patients were in each of the
drug- and vehicle-treated groups. No differences were found with respect to
grades, Glasgow Outcome Scale scores, or values for an index that measured
cognitive impairment in all tests, but vehicle-treated patients were more
impaired with respect to measures of concentration, sustained attention, and
psychomotor speed (P < 0.02), as well as debilitating fatigue (P < 0.01).
CONCLUSION: The finding that the patients in the drug-treated group exhibited
fewer impairments typical of diffuse cortical damage could be viewed as being
consistent with the hypothesis that tirilazad mesylate protects neurons. Given
the small size of this study, these results require confirmation with larger
patient groups. Future drug trials should consider including neuropsychological
tests in assessments of outcomes after SAH. If this is too costly, questions
regarding fatigue levels might prove worthwhile.
PMID- 9766305
TI - Nonneoplastic intramedullary spinal cord lesions mimicking tumors.
AB - OBJECTIVE: We report a group of nine patients with atypical, nonneoplastic
intramedullary spinal cord lesions. By retrospectively reviewing these patients,
we hoped to elucidate characteristics that would identify these patients as
harboring nonneoplastic lesions before surgical intervention. METHODS: We
reviewed the histological findings of 212 patients undergoing surgery for
intramedullary spinal cord tumors between 1989 and 1994. We identified nine
patients with nonneoplastic lesions (4%); case histories and radiographs were
reviewed. RESULTS: All patients were evaluated preoperatively using magnetic
resonance imaging. The extent of enhancement with gadolinium varied from
homogeneous enhancement to no enhancement. All lesions showed marked T2 changes.
There was a lack of significant spinal cord expansion associated with the lesions
in all cases. All patients underwent surgery. The histology of the surgical
specimens showed demyelinating lesions in four patients, sarcoidosis in two
patients, amyloid angiopathy in two patients, and a mass of nonneoplastic
inflammatory cells of unknown origin in one patient. CONCLUSION: Although it was
difficult to antecedently distinguish these lesions from neoplastic spinal cord
tumors by case history and physical examination, the most consistent clue was
absent or minimal spinal cord expansion on the preoperative magnetic resonance
images.
PMID- 9766306
TI - Lateral extracavitary approach for thoracic and thoracolumbar spine trauma:
operative complications.
AB - BACKGROUND: The lateral extracavitary approach (LECA) to the thoracic and
thoracolumbar spine allows ventral decompression and dorsal fixation of the spine
through the same incision during a single procedure. The approach, however, is
technically demanding and time-consuming. We sought to determine the incidence of
complications associated with the LECA in patients with acute thoracolumbar spine
injuries. PATIENTS AND METHODS: A retrospective chart review of all patients with
acute fractures or dislocations of the thoracic or thoracolumbar spine who
underwent surgery via the LECA was conducted to assess the incidence and type of
perioperative complications associated with the LECA. RESULTS: Thirty-three
patients with thoracic or thoracolumbar spine injuries treated using the LECA
between June 1990 and June 1996 were identified and had available medical
records. Complications occurred in 18 of these patients. Pulmonary complications
predominated. Eleven patients required tube thoracostomy for hemothorax or
persistent pleural effusions, and seven patients developed postoperative
pneumonia. There were no cases of neurological worsening. There was no mortality.
CONCLUSION: Decompression and stabilization of acute thoracolumbar fractures with
the LECA in the acute setting is associated with a 55% incidence of morbidity.
Whereas some of this morbidity may be attributed to the effects of the injury,
there is a certain intrinsic morbidity associated with the LECA. Although this
morbidity may compare favorably with that of sequential ventral/dorsal
approaches, the biomechanical advantages obtained with a combined ventral and
dorsal construct must be balanced against the inherent morbidity of such
approaches.
PMID- 9766307
TI - Microvascular decompression for pediatric onset trigeminal neuralgia.
AB - BACKGROUND: Trigeminal neuralgia (TGN) is generally a disease of the elderly.
Vascular compression, the causative agent in the majority of cases, is thought to
result from atherosclerotic changes within the vessels of the posterior fossa.
Rarely, the disease presents during childhood, before the onset of severe
atherosclerotic changes. We therefore sought to explore the role of vascular
compression in pediatric patients with medically refractory TGN. PATIENTS AND
METHODS: Twenty-three patients were identified in whom the onset of typical TGN
had occurred during childhood (age 18 yr or younger) and who underwent
exploration of the cerebellopontine angle. Twenty-two of 23 underwent
microvascular decompression (MVD) of the trigeminal nerve. Twenty-one of these
patients were followed for more than 1 year. A retrospective chart review was
conducted to determine the efficacy of MVD for the treatment of TGN in this
select population. Operative findings were recorded and correlated with patient
outcome. RESULTS: Twenty-two of 23 patients (96%) were found to have vascular
compression of the trigeminal nerve at the time of exploration. One patient was
found to have an epidermoid tumor. MVD resulted in complete pain relief at the
time of discharge in 16 of 22 patients (73%), with an additional 4 patients (18%)
having a greater than 75% diminution of pain. The 21 patients who were followed
for at least 1 year were followed for a mean of 105 months. At the time of their
last follow-up, 9 of these patients (43%) continued to have complete pain relief
and 3 (14%) had a greater than 75% diminution of pain. The most common operative
finding was a vein compressing the nerve, often in combination with a branch of
the superior cerebellar artery. DISCUSSION: MVD has been demonstrated to be a
safe and efficacious treatment for TGN in the adult population. Patients whose
symptoms begin in childhood do not enjoy the same therapeutic response to MVD as
do patients with TGN onset in adulthood. An increased incidence of venous
compression was noted in this population, as was a longer duration of symptoms
before MVD. These factors may be responsible for the decreased efficacy of MVD in
this patient population.
PMID- 9766308
TI - Pediatric low-grade gliomas: prognosis with proton magnetic resonance
spectroscopic imaging.
AB - OBJECTIVE: Our aim was to assess the correlation between the low-grade glioma
(LGG) metabolic profile and tumor progression. Using in vivo proton magnetic
resonance spectroscopic imaging, we specifically asked whether and which
metabolic features are associated with tumor regrowth or recurrence. METHODS:
Eleven pediatric patients with histologically proven partially resected (<20%
resection) midline LGG were treated and followed up for a period of 2 years. All
patients underwent proton magnetic resonance spectroscopic imaging studies before
any management was determined. Tumor progression was defined as radiological
evidence of mass enlargement (>25%) during the follow-up period. Proton magnetic
resonance spectroscopic imaging was performed using a PRESS-CSI sequence on a
General Electric 1.5-tesla scanner (General Electric Medical System, Waukesha,
WI). The signal intensities of N-acetylaspartate, choline (CHO), and creatine
from the tumor and the normal brain were used to calculate normalized metabolite
intensities and metabolite ratios. RESULTS: Tumors that progressed during a 2
year period displayed higher normalized CHO than those that remained stable (Mann
Whitney test, P < 0.03). The majority (five of six) of the rapidly growing LGG
showed values of normalized CHO of at least 1, whereas the nonprogressors had a
normalized CHO value of less than 1. CONCLUSION: In association with pediatric
LGG, high normalized CHO values seem to herald the potential for rapid tumor
growth. These observations may be valuable for defining subsets of patients with
LGG who may benefit from early therapeutic interventions.
PMID- 9766309
TI - Depth electrode implantation in the length axis of the hippocampus for the
presurgical evaluation of medial temporal lobe epilepsy: a computed tomography
based stereotactic insertion technique and its accuracy.
AB - OBJECTIVE: An individualized computed tomography-based stereotactic technique for
the longitudinal insertion of intrahippocampal electrodes is presented and its
accuracy described. METHODS: The technique makes use of one well reproducible
target in the hippocampal head and of the approximate inclination of the
anteroposterior length axis of the hippocampus, for which the orbital floor is
taken as an auxiliary landmark. It was used in 141 patients with medically
intractable complex partial seizures. In 106 patients, magnetic resonance imaging
(MRI) was available for assessment of implantation accuracy. Each of the 212
electrodes was plotted on topographic drawings and its goodness of fit rated.
RESULTS: Whereas hippocampal head and body were hit by 97 and 96% of the
electrodes, respectively, the amygdala was hit by only 75% of the electrodes and
mainly at its basal margin. For 93% of the electrodes, the inclination in a
sagittal plane corresponded exactly to that of the hippocampus. The implantation
morbidity amounted to 5.7%, whereas permanent neurological deficit occurred in
one (0.7%) of the 141 patients. CONCLUSION: This computed tomography-based
protocol proved to be reliable and hence can be considered as an adequate
alternative to MRI-based stereotactic implantation if MRI is not available or if
a single MRI-based stereotactic set-up is unreliable because of intolerable
distortions.
PMID- 9766310
TI - Low-frequency ultrasound penetrates the cranium and enhances thrombolysis in
vitro.
AB - OBJECTIVE: Refinements of treatment methods are sought to rapidly reduce the
volume of intracranial clots and to decrease patient exposure to possible
complications of thrombolytic therapy for intracranial hematomas. We assessed the
possibility of adding ultrasonication using model systems including human blood
clots and temporal bone in vitro. METHODS: The transmittance of ultrasound
through temporal bone obtained at autopsy was compared between the frequencies
211.5 KHz and 1.03 MHz, using a meter to determine the power delivered. The
frequency 211.5 KHz was chosen to assess the ultrasound effect on the weight of
24-hour-old clots prepared from human blood after exposures at 37 degrees C to 2
mg/ml urokinase with no additional treatment, ultrasound, or agitation during an
interval of up to 12 hours. At these times, fibrin degradation products also were
measured. RESULTS: The transmittance of low-frequency ultrasound (211.5 KHz)
through temporal bone was approximately 40%, which is four times higher than that
of high-frequency ultrasound (1.03 MHz). Ultrasound but not agitation
significantly increased clot lysis (140% of lysis with urokinase alone), with
correspondingly increased fibrin degradation products. CONCLUSION: We conclude
that low-frequency ultrasound transmits well through human temporal bone and
enhances thrombolysis in vitro. Clinically, this method may be promising for
reducing dosages of thrombolytic agents and shortening the period of clot
removal.
PMID- 9766312
TI - Surgical anatomy of the infratemporal fossa: the styloid diaphragm revisited.
AB - INTRODUCTION: The infratemporal fossa (ITF) gives passage to most major cerebral
vessels and cranial nerves. Dissection of the ITF is essential in many of the
lateral cranial base approaches and in exposure of the high cervical internal
carotid artery (ICA). We reviewed the surgical anatomy of this region. METHODS:
Direct foraminal measurements were made in seven dry skulls (14 sides), and the
relationship of these foramina to each other and various landmarks were
determined. Ten ITF dissections were performed using a preauricular subtemporal
infratemporal approach. Preliminary dissections of the extracranial great vessels
and structures larger than 1 cm were performed using standard macroscopic
surgical techniques. Dissection of all structures less than 1 cm was conducted
using microsurgical techniques and instruments, including the operating
microscope. The anatomic relationships of the muscles, nerves, arteries, and
veins were carefully recorded, with special emphasis regarding the relationship
of these structures to the styloid diaphragm. The dissection was purely
extradural. RESULTS: The styloid diaphragm was identified in all specimens. It
divides the ITF into the prestyloid region and the retrostyloid region. The
prestyloid region contains the parotid gland and associated structures, including
the facial nerve and external carotid artery. The retrostyloid region contains
major vascular structures (ICA, internal jugular vein) and the initial exocranial
portion of the lower Cranial Nerves IX through XII. Landmarks were identified for
the different cranial nerves. The bifurcation of the main trunk of the facial
nerve was an average of 21 mm medial to the cartilaginous pointer and an average
of 31 mm medial to the tragus of the ear. The glossopharyngeal nerve was found
posterior and lateral to stylopharyngeus muscle in nine cases and medial in only
one. The vagus nerve was consistently found in the angle formed posteriorly by
the ICA and the internal jugular vein. The spinal accessory nerve crossed
anterior to the internal jugular vein in five cases and posterior in another five
cases. It could be located as it entered the medial surface of the
sternocleidomastoid muscle 28 mm (mean) below the mastoid tip. The hypoglossal
nerve was most consistently identified as it crossed under the
sternocleidomastoid branch of the occipital artery 25 mm posterior to the angle
of the mandible and 52 mm anterior and inferior to the mastoid tip. CONCLUSION:
The styloid diaphragm divides the ITF into prestyloid and retrostyloid regions
and covers the high cervical ICA. Using landmarks for the exocranial portion of
the lower cranial nerves is useful it identifying them and avoiding injury during
approaches to the high cervical ICA, the upper cervical spine, and the ITF.
PMID- 9766311
TI - Optical coherence tomography for neurosurgical imaging of human intracortical
melanoma.
AB - OBJECTIVE: Intraoperative identification of brain tumors and tumor margins has
been limited by either the resolution of the in vivo imaging technique or the
time required to obtain histological specimens. Our objective was to evaluate the
feasibility of using optical coherence tomography (OCT) as a high-resolution,
real-time intraoperative imaging technique to identify an intracortical melanoma.
INSTRUMENTATION: OCT is a new, noncontact, high-speed imaging technology capable
of resolutions on the micrometer scale. OCT is analogous to ultrasound B-mode
imaging, except that reflections of infrared light, rather than sound, are
detected. OCT uses inherent tissue contrast, rather than enhancement with dyes,
to differentiate tissue types. The compact, fiberoptic-based design is readily
integrated with surgical instruments. METHODS: A portable handheld OCT surgical
imaging probe has been constructed for imaging within the surgical field.
Cadaveric human cortex with metastatic melanoma was harvested and imaged in two
and three dimensions. Changes in optical backscatter intensity were used to
identify regions of tumor and to locate tumor margins. Structures within the
optical coherence tomographic images were compared with the histological slides.
RESULTS: Two-dimensional images showed increased optical backscatter from regions
of tumor, which was quantitatively used to determine the tumor margin. The images
correlated well with the histological findings. Three-dimensional reconstructions
revealed regions of tumor penetrating normal cortex and could be resectioned at
arbitrary planes. Subsurface cerebral vascular structures could be identified and
were therefore avoided. CONCLUSION: OCT can effectively differentiate normal
cortex from intracortical melanoma based on variations in optical backscatter.
The high-resolution, high-speed imaging capabilities of OCT may permit the
intraoperative identification of tumor and the more precise localization of tumor
margins.
PMID- 9766313
TI - A paramedian tangential approach to lumbosacral extraforaminal disc herniations.
AB - OBJECTIVE: Extraforaminal disc herniations today are operated on via the so
called lateral approach. Clinical experience has shown that in contrast to levels
L2/3-L4/5, this approach may become extremely difficult at the L5-S1 level.
According to new microanatomic studies, the previous lateral approaches at this
level often do not allow access to the neuroforamen without partial or total
destruction of the L5-S1 facet joint. Postoperatively, this may lead to joint
irritation with consecutive low back and pseudoradicular pain. To preserve the
facet joint, a new approach was developed based on an anatomic study. METHODS:
The approach was first considered with the help of bone specimens including
ilium, vertebra 5, and sacrum. Thereafter, lumbar maceration specimens were
prepared leaving ligaments, intervertebral discs, and joints intact. From these
specimens, bony and ligamentous landmarks were deduced. Finally, the approach was
tested on seven cadavers. Subsequently, the approach was performed on 13 patients
and the intraoperative findings, the clinical feasibility, and the postoperative
results were analyzed. APPROACH: After a transverse skin incision above the
dorsal curvature of the ilium, the paravertebral muscles are dissected from the
ilium medially toward the spinous process. Lateral from the apophyseal joint, a
canal is drilled through the spongiosa of the sacrum. Primarily, a thin layer of
inner cortex is spared to protect the content of the neuroforamen. Subsequently,
it can easily be removed with the dissector to enter the extraforaminal space. In
the depth of the drilled canal, the nerve root is found, because it is fixed at
the sacrum near the disc space by the anterior lumbosacral ligaments. Riding on
the nerve root, the intertransverse ligament and muscle can be removed with the
punch. It is then possible to see the neuroforamen and extraforaminal space in
front of the joint. Free fragments and contained discs can then easily be found
and removed. CONCLUSION: Using this new approach, the L5-S1 joint remains intact.
Space for instrumental manipulations is created in areas not essential for joint
function. For this procedure, newly defined anatomic landmarks, such as the
ileolumbar ligament, upper edge of the sacrum, lateral rim of the apophyseal
joint, and para-articular notch, guide the operative route. In accordance with
the preliminary anatomic studies, this approach was successfully used in 13
patients, and we think that it is a promising alternative that helps to preserve
joint function and dorsal root ganglion integrity.
PMID- 9766314
TI - Endothelin and subarachnoid hemorrhage: an overview.
AB - INTRODUCTION: Delayed cerebral vasospasm occurring after subarachnoid hemorrhage
(SAH) is still responsible for a considerable percentage of the morbidity and
mortality in patients with aneurysms. It has been suggested that the pathogenesis
of delayed cerebral vasospasm is related to a number of pathological processes,
including endothelial damage and smooth muscle cell contraction resulting from
spasmogenic substances generated during lysis of subarachnoid blood clots,
changes in vascular responsiveness, and inflammatory or immunological reactions
of the vascular wall. It has been recognized that the endothelium plays an
important role in the regulation of the cerebral vascular tone. In 1988,
endothelin (ET)-1, a potent vasoconstrictor, was isolated from cultured porcine
aortic endothelial cells. RESULTS: ET-1, which is one of three distinct isoforms
of ETs (ET-1, ET-2, and ET-3), has a more marked effect on cerebral arteries than
do the other two isoforms. Elevated levels of ETs have been demonstrated in the
cerebrospinal fluid and plasma of patients after SAH and cerebral infarction. ETs
act by at least three different receptor subtypes, the ET(A) receptor, which is
localized in vascular smooth muscle cells and mediates vasoconstriction, and two
different ET(B) receptor subtypes. The ET(B1) receptor subtype is present in
vascular endothelial cells and mediates the endothelium-dependent vasodilation.
The ET(B2) receptor subtype is present in smooth muscle cells causing
vasoconstriction. ET-1 acts from the adventitial but not from the luminal side of
cerebral arteries. In vivo and in vitro ET-1 causes a dose-dependent and long
lasting vasoconstriction, similar to cerebral vasospasm after SAH. The
vasoconstriction caused by ET-1 can be reversed by selective ET(A) receptor
antagonists or combined ET(A) and ET(B) receptor antagonists. CONCLUSION: The
results of current clinical and experimental investigations support the
hypothesis that ET-1 is a major cause of cerebral vasospasm after SAH. Other
studies indicate that SAH causes complex changes in the ET system and increased
ET-1 levels after SAH, which are not solely responsible for the development of
vasospasm but may occur after cerebral ischemia. Further investigations are
therefore needed to clarify these different hypotheses.
PMID- 9766315
TI - Strategies to circumvent vascular barriers of the central nervous system.
PMID- 9766316
TI - Improving drug delivery to intracerebral tumor and surrounding brain in a rodent
model: a comparison of osmotic versus bradykinin modification of the blood-brain
and/or blood-tumor barriers.
AB - OBJECTIVE: To compare transient blood-brain barrier disruption (BBBD) by
hypertonic mannitol with pharmacological modification of the blood-tumor barrier
by the vasoactive peptide bradykinin for delivery of small and large agents to
nude rat intracerebral xenografts. METHODS: Female nude rats (n = 104) with 6-day
intracerebral human small cell lung carcinoma tumors were treated using BBBD (n =
24), intracarotid bradykinin (n = 38), or saline (controls, n = 32) administered
intra-arterially. During or immediately after infusion, the rats were given
radiolabeled agent (methotrexate or dextran 70; Dupont NEN, Boston, MA). The rats
were killed 10 minutes later, and samples of tumor and brain regions were
obtained for scintillation counting. Twenty-two additional rats were examined
using magnetic resonance imaging after administering one of two contrast agents
(gadoteridol or iron oxide nanoparticles) or saline (controls) in conjunction
with BBBD or bradykinin. RESULTS: After BBBD, the delivery of both small
(methotrexate) and large (dextran 70) radiolabeled tracers was increased 2- to 6
fold in the tumor and 3- to 20-fold in surrounding brain, as compared with saline
controls. After bradykinin treatment, there was minimal change in delivery of
methotrexate or dextran 70 to tumor and brain around tumor, with the greatest
increase less than 60% over controls. Magnetic resonance imaging demonstrated
increased delivery of both small and large contrast agents to the treated
hemisphere after BBBD. In comparison, no increased tumor enhancement could be
detected after bradykinin treatment. CONCLUSION: BBBD resulted in global delivery
of a variety of agents in a wide range of sizes. In this human brain tumor
xenograft model, bradykinin was not effective at increasing delivery to the tumor
of any agent tested.
PMID- 9766317
TI - Expression of endothelin(A) receptors in human gliomas and meningiomas, with high
affinity for the selective antagonist PD156707.
AB - OBJECTIVE: Endothelin (ET) immunoreactivity, ET production, and specific ET
receptors have been identified in the brain. Changes in ET concentration or
receptor expression have been implicated in the pathophysiological changes in
vasospasm after subarachnoid hemorrhage and in cerebral neoplasia. In this study,
we have characterized the ET(A) and ET(B) receptor subtypes present in human
normal cerebral cortex (NCC) and two common central nervous system tumors, i.e.,
meningioma (MNG) and glioblastoma multiforme (GBM). A knowledge of the ET
receptor subtypes present may provide a novel therapeutic target for newly
developed ET antagonists. METHODS: Saturation, competition, and autoradiographic
studies were performed with the subtype-specific radioligands 125I-PD151242 and
125I-BQ3020, to characterize the ET(A) and ET(B) receptors present in NCC, MNG,
and GBM. RESULTS: NCC expresses high-affinity ET(A) receptors on pial and
intraparenchymal vessels and high-affinity ET(B) receptors on glia and neurons.
MNGs express mainly (85%) high-affinity ET(A) receptors in a diffuse pattern,
whereas GBMs express high-affinity ET(A) receptors on the neovasculature and
ET(B) receptors on the nonvascular elements. The ET antagonist PD156707 (Kd =
0.059 nmol/L) showed a higher affinity for the ET(A) receptor subtype than did
bosentan (Kd = 1.1 nmol/L). CONCLUSION: ET(A) receptors are expressed in high
concentrations in MNGs and in the vasculature of NCC and GBMs. The ET(A)
selective antagonist PD156707 may be of potential therapeutic value in vascular
and neoplastic diseases of the central nervous system.
PMID- 9766318
TI - Consistent injury in the striatum of C57BL/6 mice after transient bilateral
common carotid artery occlusion.
AB - OBJECTIVE: The recent availability of transgenic mice enables us to study the
functional role of single gene products in cerebral ischemia. To establish an
experimental murine model of transient forebrain ischemia, this study examined
the temporal profile of ischemic neuronal damage in the striatum after bilateral
common carotid artery occlusion. METHODS: C57BL/6 mice, which are frequently used
for genetic manipulations, were subjected to 15-minute bilateral common carotid
artery occlusion. Ischemic injury was examined (4, 8, 24, 48, and 96 h after
reperfusion) by Nissl staining, terminal deoxynucleotidyl transferase-mediated
deoxyuridine triphosphate-biotin nick-end-labeling, and nuclear staining with
Hoechst 33258 dye. RESULTS: Regional cerebral blood flow was decreased to 11 +/-
6% of control values during the ischemic insult. Striatal injury was observed in
95% of animals examined after 15-minute bilateral common carotid artery
occlusion. The number of small and medium-size neurons in the striatum was
significantly (P < 0.05) decreased 8 hours after reperfusion and continued to
decrease until 96 hours, whereas the number of large neurons remained constant.
Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin
nick-end-labeling-positive cells appeared in the dorsomedial region of the
striatum 48 hours after the ischemic insult and throughout the striatum 96 hours
after the ischemic insult. Brain sections stained with Hoechst 33258 dye also
demonstrated apoptotic nuclei 96 hours after the ischemic insult. CONCLUSION:
Striatal injury after transient forebrain ischemia is reproducible in C57BL/6
mice and is a good model to study the molecular mechanisms of ischemic injury,
including delayed neuronal death, using transgenic mice.
PMID- 9766319
TI - Immunohistochemical localization of tissue plasminogen activator in vascular
endothelium of stroke-prone regions of the rat brain.
AB - OBJECTIVE: Tissue plasminogen activator (tPA), a major regulator of fibrinolysis,
is present in cerebrovascular endothelium. We have suggested that local
regulation of tPA synthesis and release in brain microcirculation could be
important determinants of the degree of damage after cerebral ischemia. In this
study, the normal distribution of tPA antigen was determined in several stroke
prone regions in the rat brain often used to study the pathophysiological
consequences of cerebral ischemia. METHODS: Immunohistochemistry and Western blot
analysis were performed using an antibody that detects free tPA antigen and tPA
complexed to its rapid inhibitor, plasminogen activator inhibitor-1 (PAI-1).
Staining for von Willebrand factor, a brain endothelial cell marker, served as a
positive control. RESULTS: Relative to von Willebrand factor, 8.6, 13, 11.4, and
20.4% of vessels in the parietal cortex, frontal cortex, striatum, and
hippocampus, respectively, were tPA-positive. The majority of tPA-positive
vessels (58-75%) were classified as precapillary arterioles and postcapillary
venules (7-20 microm), whereas capillaries (4-7 microm) and small arterioles and
venules (20-40 microm) accounted for 11 to 22% and 11 to 19%, respectively, of
tPA-positive vessels. Western blot analysis of brain microvascular proteins
confirmed the presence of free tPA (67 kDa) and a stronger band representing tPA
PAI-1 complexes. CONCLUSION: The tPA-containing cerebrovascular endothelium is
distributed mainly in smaller vessels. In addition to the free pool of tPA, a
large portion of tPA is complexed to PAI-1 and is therefore functionally
inactive. The size of the free tPA cerebrovascular pool may be regulated by PAI
1, which in turn could suppress fibrinolysis in the cerebral microcirculation.
PMID- 9766320
TI - The history of neurological surgery at Northwestern University.
AB - The residency program in neurological surgery at Northwestern University was
founded in 1924 by Loyal Davis and was formally accredited by the American Board
of Neurological Surgery in 1946. Allen Kanavel, mentor to Davis, was one of the
original members of the Society of Neurological Surgeons. Five individuals have
served as chief of neurosurgery at Northwestern: Davis, Paul Bucy, Anthony
Raimondi, Albert Butler, and H. Hunt Batjer. Davis was the first surgeon west of
the Appalachians to limit his work to neurosurgery. Between 1954 and 1963, there
were two independent neurosurgery residency programs at Northwestern, one headed
by Davis and the other by Bucy. A master surgeon and superb teacher, Bucy trained
more than 65 residents and became one of the greatest authors and leaders in the
field of neurosurgery. Neurosurgical training at Northwestern has traditionally
emphasized excellence of patient care, strong resident and student teaching, and
basic science research. Through the years, a major strength of the program has
been its clinical volume and diversity. Four hospitals have played major roles in
the program: Northwestern Memorial Hospital (created by the merger of Chicago
Wesley Memorial Hospital and Passavant Memorial Hospital), Children's Memorial
Hospital, Evanston Hospital, and the Veterans Administration Lakeside Hospital.
This article traces the development of neurological surgery at Northwestern, with
an emphasis on its historical background and the contributions of Kanavel, Davis,
and Bucy. The present philosophy and structure of the training program and the
program's future under the direction of Batier are also described.
PMID- 9766321
TI - Carotid-coronary artery bypass graft conundrum.
PMID- 9766322
TI - Extrapontine myelinolysis and behavioral change after transsphenoidal pituitary
surgery: case report.
AB - OBJECTIVE AND IMPORTANCE: Rapid correction of hyponatremia is considered the
usual cause of central pontine myelinolysis and extrapontine myelinolysis. Little
has been reported about mental changes associated with this disorder or its
occurrence after transsphenoidal surgery. CLINICAL PRESENTATION: A 24-year-old
woman suddenly developed markedly abnormal behavior associated with rapid
correction of hyponatremia 11 days after undergoing transsphenoidal surgery for a
prolactin-secreting pituitary adenoma. INTERVENTION: Magnetic resonance imaging
and positron emission tomography with 18F-fluorodeoxyglucose showed bilateral
caudate nuclei and putaminal lesions. Gradual, complete clinical resolution
preceded the resolution that was revealed by magnetic resonance imaging.
CONCLUSION: We emphasize the importance of cautious correction with frequent
electrolyte determinations and attention to behavioral changes in the management
of delayed hyponatremia after pituitary tumor surgery.
PMID- 9766323
TI - Cervical actinomycosis causing spinal cord compression and multisegmental root
failure: case report and review of the literature.
AB - OBJECTIVE AND IMPORTANCE: Epidural invasion and the resulting cord compression
are clinical entities not usually associated with actinomycosis, and we found
only 11 reported cases of cord compression caused by Actinomyces infection in the
literature. Only one reported case was described as actinomycosis with epidural
granuloma (14, 16), whereas in the other cases, epidural macroabscess (phlegm)
formation caused the symptoms. Histopathological demonstration of the
inflammatory granulation tissue and gram-positive sulfur-containing filamentous
bacteria are important for the diagnosis of actinomycosis, because the clinical
and microbiological studies cannot always demonstrate the causative microorganism
and primary infection source. CLINICAL PRESENTATION: In this article, a case of
Actinomyces infection causing cervical cord compression is presented. Precise
diagnosis was accomplished using specific histopathological studies of the
surgical specimens; such a precise diagnosis cannot always be achieved using
preoperative investigations and microbiological studies. The treatment modalities
and the patient's outcome are also discussed. CONCLUSION: As shown by hematoxylin
and eosin stain, in contrast to the Nocardia species, Actinomyces filaments
histopathologically are basophilic in nature and terminate in eosinophilic clubs
as a predictive feature. The clinical and radiological findings closely resemble
metastatic tumors and other infectious processes. A differential diagnosis is
also emphasized in this article, along with a review of the literature.
PMID- 9766324
TI - Cervical arachnoid cysts after craniocervical decompression for Chiari II
malformations: report of three cases.
AB - OBJECTIVE AND IMPORTANCE: We describe three cases in which ventrally situated
cervical arachnoid cysts led to spinal cord or cervicomedullary compression after
repeat craniocervical decompression for Chiari II malformations. CLINICAL
PRESENTATION: All three patients underwent craniocervical decompression when
their Chiari malformations became symptomatic. The first patient developed
chronic vertiginous spells and headache and was treated with repeated
craniocervical decompression procedures during several years. Seven months after
undergoing her third decompression procedure, she developed severe dizzy spells,
which were determined to be of brain stem origin. The second patient had a small,
asymptomatic arachnoid cyst anterior to the brain stem discovered at age 6 years.
After undergoing repeat craniocervical decompression for headaches 8 years after
undergoing his first procedure, the patient developed severe neck pain and acute
quadraparesis. A third patient underwent repeat craniocervical decompression at
age 14 years for cranial nerve dysfunction. Postoperatively, he acutely developed
paresis of extraocular movements and incoordination of the upper extremities. All
three patients were found to have anteriorly situated arachnoid cysts compressing
the brain stem and/or cervical spinal cord. INTERVENTION AND TECHNIQUE:
Fenestration of the arachnoid cyst or drainage with cystoperitoneal shunting
adequately treated acute brain stem or cervical spinal cord compression. All
three patients had achieved satisfactory relief from their acute symptoms of
neural compression at their follow-up examinations. CONCLUSION: An association
between spinal arachnoid cysts and neural tube defects has previously been
reported. However, the development of previously undetected spinal arachnoid
cysts after craniocervical decompression was unexpected. We hypothesize that
extensive craniocervical decompression may alter the cerebrospinal fluid pressure
dynamics in such a way that the anterior subarachnoid space, previously
compressed, may dilate. Occasionally, because of perimedullary arachnoiditis, the
cerebrospinal fluid may become loculated and act as a mass. Direct fenestration
or shunting may successfully treat this problem, and less extensive
craniocervical decompression may avoid it.
PMID- 9766325
TI - Syringomyelia persistence after Chiari decompression as a result of
pseudomeningocele formation: implications for syrinx pathogenesis: report of
three cases.
AB - OBJECTIVE AND IMPORTANCE: We present the cases of three patients in whom
pseudomeningocele (PSM) formations after posterior fossa decompression of
hindbrain herniations (Chiari I malformations) were associated with persistence
of syringomyelia. The physiological importance of correcting this complication
has not been previously described. CLINICAL PRESENTATION: We identified three
patients who developed suboccipital PSMs after undergoing posterior fossa
decompression for hindbrain herniations and syringomyelia. All three patients
experienced persistence of their symptoms and their syringomyelia, despite
adequate posterior fossa decompression. TECHNIQUE: Subsequent exploration
revealed cerebrospinal fluid leaking either from the dural suture line (one
patient) or from perforations found within the bed of a polyglactin mesh dural
graft (two patients). Correction of the PSM resulted in resolution of both the
syringomyelia and the symptoms in all three patients. DISCUSSION: The persistence
of syringomyelia in the presence of a PSM may be the result of dissipation of the
cerebrospinal fluid systolic pressure wave into the distensible PSM cavity. This
phenomenon suggests that the cerebrospinal fluid pressure exerted on the spinal
cord surface favors resolution of the syrinx cavity.
PMID- 9766326
TI - Nocardia abscess of the choroid plexus: clinical and pathological case report.
AB - OBJECTIVE: Cerebral Nocardia abscesses are rare, accounting for approximately 1
to 2% of all cerebral abscesses. Prompt aggressive surgical treatment involving
craniotomy and excision of these lesions has been advocated by many authors,
because these lesions have significantly higher morbidity and mortality rates
than do most other cerebral abscesses. We report an atypical presentation of
cerebral nocardiosis localized to the choroid plexus of the lateral ventricle.
CLINICAL PRESENTATION: A 56-year-old man presented with a 3-week history of
fever, cough, and progressive headache and an ensuing 3-day history of
progressive lethargy, confusion, and gait ataxia. Radiographic studies
demonstrated a loculated contrast-enhancing left lateral ventricular lesion with
significant perilesional parenchymal edema that was thought preoperatively to be
a neoplasm. INTERVENTION: The patient underwent a craniotomy for resection of the
lesion. Intraoperatively, a reddish gray lesion with purulent exudate was
encountered within the left lateral ventricle intimately adherent to the choroid
plexus as well as to the ependyma and subependymal veins. A frozen section
demonstrated an organizing abscess wall. The lesion was resected in its entirety,
and multiple cultures were sent for analysis. CONCLUSION: Microbiology cultures
grew Nocardia asteroides. A course of intravenous antibiotics was started, which
included trimethoprim-sulfamethoxazole, amikacin, and ceftriaxone. Two weeks
after surgery, at the time of discharge, the patient's neurological status had
improved considerably. Although Nocardia abscesses have been documented to occur
throughout the central nervous system, the presentation of a lesion confined to
the choroid plexus of the lateral ventricle with significant parenchymal edema is
unusual and demonstrates that Nocardia abscesses must be considered in the
differential diagnosis of a contrast-enhancing intraventricular mass lesion
involving the choroid plexus.
PMID- 9766327
TI - Failure of hydroxyapatite cement to set in repair of a cranial defect: case
report.
AB - OBJECTIVE AND IMPORTANCE: Hydroxyapatite cement, a new biomaterial that is being
marketed as a method for reconstructing cranial defects, offers many advantages.
We document, herein, the complete dissolution and failure of this material to set
in a surgically dry field, under optimal conditions, an occurrence that has not
been previously reported. CLINICAL PRESENTATION: Hydroxyapatite cement was used
for reconstruction of a frontal bone defect secondary to a traumatic depressed
cranial fracture in a 9-year-old male patient. At the time of suture removal on
postoperative Day 6, we observed serous discharge from the wound, a reappearance
of the cranial defect, and brain pulsations visible subcutaneously. INTERVENTION:
The patient was returned to the operating room, at which time we learned that the
hydroxyapatite cement had migrated out of the defect; small concretions of the
cement were scattered throughout the subgaleal space. The concretions of cement
in the subgaleal space and the small amount of cement remaining in the defect
were removed, and titanium mesh was used. An excellent cosmetic result was
achieved. CONCLUSION: Although offering many advantages, hydroxyapatite cement
does carry a risk of failure to set, despite optimal technique. Causes for
failure to set, as well as possible modifications in the use of material and
technique, are discussed.
PMID- 9766328
TI - Primary stenting of the extracranial internal carotid artery in a patient with
multiple cervical dissections: technical case report.
AB - OBJECTIVE AND IMPORTANCE: Spontaneous dissection of the extracranial internal
carotid artery (ICA) and vertebral artery (VA) is a well-documented cause of
stroke in young, previously healthy patients. The majority of patients with
spontaneous dissection are successfully treated with antiplatelet or
anticoagulation therapy, but a significant proportion of patients progress to
suffer devastating morbidity and mortality. Surgical intervention has primarily
consisted of proximal ligation, extracranial-intracranial bypass, or
endarterectomy. Generally, these procedures are technically demanding and yield
disappointing clinical results. CLINICAL PRESENTATION/INTERVENTION: A 36-year-old
man without a significant medical history initially presented with a several-day
history of episodic right upper extremity weakness and numbness and visual
obscurations. Cerebral angiography revealed bilateral ICA long segment narrowing
(95%), distal left VA high-grade (95%) stenosis compatible with dissections, and
right VA proximal occlusion. While therapeutically anticoagulated on heparin, the
patient continued to experience crescendo episodes of right upper extremity
paresis and paresthesias as well as aphasia. The patient underwent primary
stenting of the left ICA, using a series of six overlapping stents (three
Gianturco-Roubin coronary stents and three Palmaz-Schatz coronary stents). The
patient remained symptom-free without neurological complications, and subsequent
angiography performed at the 9-month follow-up examination confirmed continued
patency of the stented left ICA as well as recanalization of the right ICA and
VA. CONCLUSION: Neurovascular stents offer a minimally invasive and potentially
efficacious treatment for the prevention of cerebral ischemia in patients with
spontaneous extracranial dissection who remain symptomatic despite therapeutic
anticoagulation.
PMID- 9766329
TI - Reversibility of severe sagittal sinus thrombosis with open surgical thrombectomy
combined with local infusion of tissue plasminogen activator: technical case
report.
AB - OBJECTIVE: To explore the controversial issue of anticoagulant therapy and
indications for surgery in association with severe sinus thrombosis. METHODS:
During the last 4 years, we have treated three patients with severe sinus
thrombosis of the dural sinuses. All three patients received systemic
anticoagulant therapy and, after experiencing neurological deterioration,
underwent open thrombectomy and local thrombolysis. After the operation,
aggressive intensive care was given and included cerebral perfusion monitoring,
barbiturate administration, hyperventilation, and osmotherapy. The treatment was
guided by repeated neuroradiological investigations. RESULTS: All three patients
returned to their normal lives. CONCLUSION: Intracranial sinus thrombosis, even
in the worst neurological state, should be treated aggressively. A cornerstone in
treatment is systemic anticoagulant therapy and repeated neuroradiological
studies. When, despite adequate anticoagulant therapy and intensive care,
neurological deterioration occurs, a combination of open thrombectomy and local
thrombolytic therapy should be considered.
PMID- 9766330
TI - Traumatic intraventricular hemorrhage treated with intraventricular recombinant
tissue plasminogen activator: technical case report.
AB - OBJECTIVE AND IMPORTANCE: Traumatic intraventricular hemorrhage (IVH) can result
in association with acute obstructive hydrocephalus, repetitive malfunction of
external ventricular drains (EVDs), and uncontrollable increased intracranial
pressure. We report a case showing the safe and effective use of intraventricular
recombinant-tissue plasminogen activator in a child with severe brain injury and
acute hydrocephalus from IVH. CLINICAL PRESENTATION: A 15-year-old male patient
presented to us after a motor vehicle accident with bilateral extensor posturing,
intracerebral and IVH, and acute obstructive hydrocephalus. INTERVENTION: A right
EVD was placed and functioned only transiently. A left EVD was placed and
functioned only transiently. Because of the inability to maintain ventricular
drainage, rising intracranial pressure, and worsening clinical status, 5 mg of
recombinant-tissue plasminogen activator was injected through each EVD. Excellent
EVD function was obtained quickly, with control of intracranial pressure and
improvement in clinical status and without hemorrhagic complication. CONCLUSION:
With obstructive hydrocephalus secondary to acute traumatic IVH that cannot be
controlled with EVD because of recurrent obstruction from intraventricular blood,
intraventricular recombinant-tissue plasminogen activator can be effective and
safe, despite preexisting multiple hemorrhagic intracranial injuries.
PMID- 9766331
TI - Use of preoperative computed tomography-angiography in cranial remodeling:
technical note.
AB - OBJECTIVE/IMPORTANCE: One of the most severe complications of craniosynostosis
repair is dural sinus laceration. Massive hemorrhage and air embolism are
potentially life-threatening sequelae that can result from such an event. The
aberrant anatomy of patients with craniosynostosis only accentuates this risk,
because separation of the calvaria from the underlying dura is often performed
without direct visualization of the sinuses. METHODS: Three-dimensional computed
tomography was combined with computed tomographic angiography in the preoperative
assessment of patients with craniofacial abnormalities. RESULTS: A clear
understanding of the dural sinus anatomy in relation to the overlying bony
landmarks became available to the operating surgeon. Six patients underwent this
procedure, with excellent visualization of the bony and sinus anatomy achieved in
all cases. CONCLUSION: It is thought, that the benefit of combining these
procedures has been significant by allowing the visualization of the dural sinus
anatomy and overlying bony landmarks. This procedure conveys minimal concomitant
morbidity or expense to the patient, yet offers valuable insight toward operative
planning and complication avoidance.
PMID- 9766332
TI - Library: historical perspective. Herbert Olivecrona (1891-1980)
PMID- 9766335
TI - The twelfth labor of Heracles.
PMID- 9766336
TI - Elastin degradation in the superficial temporal arteries of patients with
intracranial aneurysms reflects changes in plasma elastase.
PMID- 9766337
TI - The Ray Threaded Fusion Cage for posterior lumbar interbody fusion.
PMID- 9766338
TI - Visual impairment associated with mutism after posterior fossa surgery in
children.
PMID- 9766339
TI - Enterogenous cyst of the fourth ventricle: case report.
PMID- 9766340
TI - The Lipoprotein and Coronary Atherosclerosis Study (LCAS) in context: assessing
the benefits of lipid-lowering therapy. Introduction.
PMID- 9766341
TI - Assessing the benefits of lipid-lowering therapy.
AB - In recent years, a substantial body of evidence has emerged to support the use of
lipid-lowering therapy in the prevention of coronary artery disease, and many
physician groups have endorsed the management of dyslipidemia in at-risk
patients. An important consideration in such endorsements has been the issue of
the safety of lipid intervention; many early primary- and secondary-prevention
studies reported either no reduction in all-cause mortality rates or an increase
in non-coronary artery disease mortality rates in treated patients. These
observations raised serious concerns about the safety of such therapy. However, 2
landmark studies, the Scandinavian Simvastatin Survival Study (4S) and the West
of Scotland Coronary Prevention Study (WOSCOPS), have contributed greatly to
alleviating these concerns. In this article, a review of the epidemiologic
evidence supporting the use of lipid modification will be presented, including
important trials and meta-analyses, and the cost-effectiveness of lipid-modifying
treatment will be discussed.
PMID- 9766342
TI - Clinical trial endpoints: angiograms, events, and plaque instability.
AB - Clinical trials provide evidence on methods for risk assessment of coronary
artery disease and on interventions used to decrease risk. Plaque rupture, which
leads to either progression of coronary artery disease or myocardial infarction,
is the critical biologic event in the pathophysiology of atherothrombosis that
leads to morbidity and mortality. Trials with endpoints of myocardial infarction
and death provide direct information on the effect of intervention on morbidity
and mortality, but these trials require extremely large sample sizes and long
duration. To obtain clinical information more quickly and with fewer patients,
investigators have conducted trials using surrogate endpoints that examine the
effect of treatment on the underlying disease process through measures of
atherosclerotic lesion progression and/or regression and new lesion development.
Coronary angiography studies have consistently shown that lipid-modifying therapy
decreases coronary artery disease progression. The correlation between rate of
progression of coronary artery disease and clinical coronary events such as
myocardial infarction and coronary death may be explained by the relation of both
to the biologic process of plaque rupture and thrombosis.
PMID- 9766343
TI - Coronary arteriography and lipid lowering: limitations, new concepts, and new
paradigms in cardiovascular medicine.
AB - Coronary arteriography has played a central role in improving our understanding
of the mechanisms of unstable coronary syndromes and the benefits of cholesterol
lowering. However, coronary arteriography as currently used is outmoded and
inadequate for new clinical algorithms based on vigorous lipid and other risk
factor control as alternatives to invasive procedures for the primary treatment
of coronary artery disease. What is needed is a way of viewing or analyzing
noninvasive myocardial perfusion images and coronary arteriograms so as to
identify and quantify the extent or severity of diffuse coronary atherosclerosis.
Determining the relative contribution of diffuse and segmental narrowing by
definitive myocardial perfusion imaging or coronary arteriography would provide
the optimal basis for determining the need for revascularization procedures. In
the absence of significant segmental stenoses, mild or diffuse disease identified
by coronary arteriography would also provide a definitive diagnosis as the basis
for lifelong cholesterol-lowering drugs and risk factor modification, even for
patients with normal cholesterol levels. Thus, it is important to consider
several new concepts for analyzing coronary arteriograms. More physiologically
accurate invasive and noninvasive technology allows improved diagnosis and
management of coronary atherosclerosis as new paradigms in cardiovascular
medicine.
PMID- 9766344
TI - Relation of clinical benefit to metabolic effects in lipid-lowering therapy.
AB - Studies of lipid-modifying therapy show that inhibition of cholesterol synthesis
is required in at least 2 sites-in hepatic cells and in cells located in the
walls of coronary arteries-if the progression of coronary atherosclerosis is to
be decreased in patients with relatively normal levels of low-density lipoprotein
(LDL) cholesterol. This is clinically important, because the majority of patients
with coronary artery disease do not have severely elevated LDL cholesterol
levels. Of the 2 angiographic trials of 3-hydroxy-3-methylglutaryl coenzyme A
(HMG CoA) reductase inhibitors ("statins") in patients with coronary artery
disease and average cholesterol levels, only the Lipoprotein and Atherosclerosis
Study (LCAS) of fluvastatin reported slowed angiographic progression of coronary
artery disease in these patients. The change in LDL cholesterol levels during
treatment with fluvastatin did not predict the extent of change in coronary
atherosclerosis or incidence of clinical cardiac events. Apparently, the
metabolic effects of treatment with fluvastatin were more important than the
extent to which blood cholesterol levels were lowered. The clinical benefits of
treatment with statins should be directly compared in randomized controlled
clinical trials among patients with average cholesterol levels.
PMID- 9766345
TI - Economic implications of lipid-lowering trials: current considerations in
selecting a statin.
AB - Little doubt remains about the value of lipid-lowering therapy since publication
of the results of large, randomized, controlled trials that show decreased total,
as well as coronary, mortality with the use of statins for primary and secondary
prevention of coronary artery disease. All of the available statins are effective
and safe, but they vary greatly in terms of cost-effectiveness. Fluvastatin has
been determined to be a cost-effective therapeutic agent in the large proportion
of the population with mild-to-moderate dyslipidemia who fit treatment guidelines
of the National Cholesterol Education Program (NCEP). Atorvastatin and
simvastatin are cost-effective for the relatively smaller number of patients who
require greater reductions in cholesterol.
PMID- 9766346
TI - Future of lipid-lowering trials: what else do we need to know?
AB - Convincing clinical trial evidence shows that lipid-lowering therapy can be
effective in primary and secondary prevention of coronary artery disease events.
At least 2 studies indicate that this benefit extends to persons with only mild
or moderate hypercholesterolemia. The benefits of lipid-lowering therapy in
certain subpopulations, however, remains to be elucidated. The effects in women,
African Americans, the elderly, and patients with concomitant coronary artery
disease risk factors such as diabetes and hypertension are only recently being
studied in large, well-designed trials. Other trials, described herein, are
studying the benefits of therapy in persons with coronary artery disease and low
levels of high-density lipoprotein (HDL) cholesterol (but normal or only mildly
elevated total or low-density lipoprotein [LDL] cholesterol). Future trials are
needed to assess prospectively the value of aggressive lipid-lowering therapy on
coronary artery disease events in diabetic patients with and without coronary
artery disease. New drug therapies and innovative uses for existing therapies are
being developed that may have an important impact on the prevention of coronary
artery disease.
PMID- 9766347
TI - Congenital diaphragmatic hernia: developing a protocolized approach.
AB - BACKGROUND/PURPOSE: The purpose of this study was to evaluate the evolving
outcome of newborns who have congenital diaphragmatic hernia (CDH) using a
protocolized approach to management, which includes extracorporeal membrane
oxygenation (ECMO) and to present the details of such a management protocol.
METHODS: A retrospective chart review was conducted of the neonatal outcome of
near-term (>34 weeks' gestation) newborns with CDH all referred to the Royal
Alexandra Hospital either before or after delivery. A protocol was developed that
included antenatal assessment, the use of antenatal steroids, planned delivery,
use of prophylactic surfactant, pressure limited gentle ventilation, permissive
hypercarbia and hypoxia, and venovenous ECMO, if indicated. RESULTS: Sixty-five
infants with CDH were treated from February 1989 through August 1996. Twenty
three infants were inborn, 20 of whom were antenatal referrals. Overall, 51 of
the 65 infants survived (78%). Thirteen of the 23 inborn infants survived with
conservative management, and 10 required ECMO, of whom, eight were long-term
survivors. Thirty-eight infants required ECMO, and 26 survived (68%), whereas
there were only two deaths among the 27 conservatively treated infants. Eighteen
of 20 inborn infants with an antenatal diagnosis survived, compared with 13 of 21
(62%) outborn infants. An antenatal diagnosis before 25 weeks' gestation was
associated with a 60% survival rate. Sixty-three percent of infants whose best
postductal PaO2 value before ECMO was less than 100 torr survived, and 7 of 11
infants with a best postductal PaO2 value of less than 50 torr before ECMO
survived (64%). The average age at surgery progressively increased over time both
for infants who did not require ECMO (1.3 days to 5.8 days; P = .01) and for
infants who received ECMO (1.9 days to 8.2 days; P = .016). CONCLUSIONS: The use
of a protocolized management for infants with CDH has been associated with
improving outcome in a population at high risk. The components (either separately
or combined) of these protocolized approaches need to be tested in prospective
trials to determine their true benefit. In addition, there is a need to evaluate
prospectively the outcomes of infants with CDH born in ECMO centers compared with
those infants born in other tertiary care neonatal units to determine the most
appropriate management of the fetus with CDH.
PMID- 9766348
TI - Elective delayed reduction and no anesthesia: 'minimal intervention management'
for gastrochisis.
AB - PURPOSE: In a pilot study of 14 children, born when the authors were on a 1:5 "on
take" for neonatal referrals, a policy evolved of elective delayed midgut
reduction without anaesthesia or sedation in the incubator on the neonatal
surgical unit. There was no other form of selection, and it was fortunate that
the authors did not encountered any adverse criteria in this small series.
METHODS: Bowel reduction, which was pain free, was undertaken conventionally with
the same attention and with no greater difficulty than under general anesthesia.
Delaying midgut reduction for more than 4 hours led to more stable
cardiovascular, respiratory, and renal parameters. Moderate lower limb congestion
cleared rapidly. RESULTS: At the end of the procedure, all children were
conscious, and 12 were alert and indistinguishable from normal babies. A mild
periumbilical infection developed in two patients. Eleven of the 12 surviving
children established enteral nutrition within 11 to 32 days, eight within 18
days. Another child with ileal atresia and bowel dilatation required bowel
tailoring and lengthening (LILT) to allow enteral nutrition. All are physically
and developmentally normal, and none has required umbilical herniorrhaphy or
umbilicoplasty. All except one have a "scarless" abdomen and an aesthetically
normal umbilicus. In marked comparison, two children immediately and obviously
were unwell with abdominal pain, tachycardia, and metabolic acidosis. Abdominal
wall cellulitis rapidly developed in both. At laparotomy one had a midgut
volvulus and died at 22 months of short bowel syndrome (SBS) and the other with a
perforated segmental ileal atresia died at 7 months of Enterobacter cloacae
septicaemia. CONCLUSIONS: Our small study suggests that delayed midgut reduction
without anaesthesia appears safe, carrying no additional morbidity or mortality.
It helps avoid anaesthesia, muscle relaxants, and ventilation and has obvious
resource benefits. The conscious child is a safety asset, and any postreduction
deviation from a "normal, well-perfused, comfortable, and painfree" child is an
indication for urgent laparotomy. This "minimal intervention management," when
applicable, has become our preferred first option for children with
gastroschisis. Further extension of this study will determine those not eligible
for this technique and establish "exclusion criteria."
PMID- 9766349
TI - Outcome of patients operated on for esophageal atresia: 30 years' experience.
AB - PURPOSE: The aim of this study was to evaluate the outcome and late sequelae of
patients with esophageal atresia or tracheoesophageal fistula. METHODS: Sixty
patients with esophageal atresia or tracheoesophageal fistula (EA-TEF) were
treated in Tampere University Hospital in the years 1963 through 1993. Long-term
outcome was evaluated with a questionnaire, pulmonary and esophageal function
test results, 24-hour pH level monitoring, tracheobronchoscopy findings, and
esophagogastroscopy with biopsy sections and samples for bacterial cultures.
RESULTS: One third of the respondents reported having impaired quality of life
because of respiratory infections, dyspnea, and difficulties in swallowing and
coughing at night. Eighteen percent had gastroesophageal reflux (GER) symptoms.
The rate of symptoms decreased with age. Impaired pulmonary function, GER,
abnormal esophageal peristalsis, and transit time were registered.
Tracheobronchoscopy showed tracheal narrowing and inflammation in one third; in
histopathologic analysis, however, the rate of inflammation was more than
doubled. Histologically, esophageal inflammation was found in 51%, Barrett's
esophagus in 6%, and a Helicobacter pylori infection in 21% of cases. The
severity of GER, esophageal peristaltic abnormality, tracheal inflammation, and
impairment of pulmonary function seems to be alleviated with age. CONCLUSIONS:
Although the long-term outcome of EA-TEF patients seems to be favorable,
respiratory and gastrointestinal symptoms as well as functional abnormalities
remain frequent. Gastric metaplasia in the esophagus and the high rate of
tracheal, esophageal, and gastric inflammation indicate a need for long-term
follow-up.
PMID- 9766350
TI - Laparoscopic appendectomy in children performed using single endoscopic GIA
stapler for both mesoappendix and base of appendix.
AB - BACKGROUND/PURPOSE: Similar to open appendectomy (OA), most of the methods
described for laparoscopic appendectomy (LA) require two steps: (1) dissection
and division of mesoappendix and (2) excision of appendix. Dissection of
mesoappendix requires more skill and experience during LA. In single endoscopic
GIA stapler laparoscopic appendectomy technique (SESLAT), both mesoappendix and
base of appendix may be divided in one step with the application of a single
endoscopic GIA stapler. METHODS: LA was attempted in 18 patients who had acute
appendicitis and was successfully performed in 16 patients. RESULTS: In two
patients, the operation was converted to OA. The authors did not need conversion
to OA because of complication resulting from the use of the stapler. CONCLUSIONS:
SESLAT is a quick, easy, and versatile method for LA in children that obviates
dissection of mesoappendix and related complications. Thus, it enables LA to be
performed by inexperienced beginners.
PMID- 9766351
TI - Hepatocellular carcinoma in children: clinical review and comparison with adult
cases.
AB - BACKGROUND: Hepatocellular carcinoma (HCC) in children was rarely reported and
usually included with hepatoblastoma in most studies of pediatric liver
malignancies despite different clinical behaviors. The authors report their
experience in pediatric HCC and discuss its differences from adult HCC. METHODS:
A retrospective review of radiographic, laboratory, pathological, and therapeutic
data in 55 children with HCC was performed. The liver function was graded by
modified Child's classification. Kaplan-Meier survival curves in various
therapeutic and Child's groups were plotted, and log-rank test was used to detect
differences among survival curves. RESULTS: Although children with HCC mostly
presented with advanced disease at diagnosis, disturbances of liver function were
unremarkable. Sixty-eight percent of cases concurred with liver cirrhosis. The
median survivals for resectable, chemotherapeutic, and untreated HCCs were 23, 3,
and 2 months, respectively. Resectable HCC significantly posed a much better
prognosis. However, the resectability was unsatisfactory (18.2%). Resection was
limited because of anatomic unfeasibility including bilateral involvement
(62.5%), portal vein thrombi (41.7%), distant metastasis (29.1%), para-aortic
lymphadenopathy (18.8%), inferior vena cava thrombi (16.7%), and hilar invasion
(6.3%). Distant metastasis was the most ominous for survival in children with
unresectable HCC. CONCLUSIONS: HCC behaved somewhat differently between children
and adults. Surgical resection represented the best hope of long-term survival.
The outcome in children could not keep up with that in adults because of a
diagnostic delay. Hence, alpha-fetoprotein and sonography screening in carrier
children should be worthwhile.
PMID- 9766352
TI - Pleural effusions in lymphoblastic lymphoma: a diagnostic alternative.
AB - BACKGROUND: Children with large anterior mediastinal masses frequently present
with severe respiratory compromise and often pose a difficult diagnostic dilemma.
A biopsy is preferred for diagnosis before treatment can begin; however, many of
these children are at risk of acute clinical deterioration and cardiovascular
arrest with the induction of anesthesia. The authors noted a correlation between
pleural effusions and lymphoblastic lymphoma and recently diagnosed three cases
of lymphoblastic lymphoma in children with a large anterior mediastinal mass and
pleural effusion through cytological and flow cytometric examination of the
pleural fluid. METHODS: To focus on this problem, 101 pediatric patients
presenting with an anterior mediastinal mass between January 1980 and September
1994 were reviewed to determine if pleural effusions occur more frequently at
initial presentation with lymphoblastic lymphoma than with Hodgkin's disease,
thus offering a means of diagnosis in children with severe respiratory
compromise. The patients' chest radiographs and/or computed tomograms for the 88
cases in which they were available were reviewed retrospectively in a blinded
fashion to identify those children with pleural effusions at the time of
presentation. RESULTS: In this study, 71% of patients with lymphoblastic lymphoma
(10 of 14) had a pleural effusion at presentation, whereas only 11.7% of patients
with Hodgkin's disease (7 of 60) had a pleural effusion on initial presentation.
(P < .002 Fisher's Exact test). CONCLUSION: This retrospective review suggests
that there is a significantly greater association of pleural effusions in
patients with lymphoblastic lymphoma than with Hodgkin's disease. Our experience
supports the conclusion that thoracentesis may provide a means of diagnosis in
children presenting in severe respiratory compromise obviating the need for
anesthesia and open biopsy.
PMID- 9766353
TI - Hypoxic pulmonary vasoconstriction is impaired in rats with nitrofen-induced
congenital diaphragmatic hernia.
AB - BACKGROUND: Pulmonary hypertension and persistent fetal circulation contribute to
the high mortality rate associated with congenital diaphragmatic hernia (CDH).
Morphological alterations of the pulmonary vasculature in infants with CDH are
thought to contribute to exaggerated vasoconstrictor responses to normal
vasoconstrictor stimuli. In the pulmonary circulation, hypoxia is a potent
vasoconstrictor. Under pathological conditions, hypoxia-induced vasoconstriction
may contribute to the development of pulmonary hypertension. METHODS: The authors
have used the nitrofen-induced model of congenital diaphragmatic hernia in rats
to investigate the magnitude of the hypoxic vasoconstrictor response. Congenital
diaphragmatic hernias were induced in fetal rats by feeding nitrofen (2,4
dichlorophenyl-p-nitrophenyl ether) to pregnant Sprague-Dawley rats at
midgestation. Hypoxia-induced vasoconstriction was measured in isolated, perfused
third-generation pulmonary arterioles from normal rats and from rats with
nitrofen-induced CDH. RESULTS: The hypoxic vasoconstrictor response was
significantly blunted in the pulmonary arterioles of fetal rats with nitrofen
induced (2% +/- 1% vasoconstriction), as compared with the responses observed in
normal fetal rats (15% +/- 3% vasoconstriction, P = .004). CONCLUSION: Blunting
of the hypoxic pulmonary vasoconstrictor response may contribute to ventilation
perfusion mismatching in infants with CDH.
PMID- 9766354
TI - Gastric tubes in children with caustic esophageal injury: a 32-year review.
AB - PURPOSE: Caustic injury to the upper aerodigestive system with scarring of the
pharynx, hypopharynx, and esophagus is a challenging reconstructive problem. The
author has used the gastric tube for this purpose for three decades. METHODS:
During the last 32 years (1965 to 1996 inclusive) the author treated 11 patients
who required esophageal replacement with a gastric tube conduit, which was
anastomosed to the cervical esophagus. At the time of injury, ages ranged from 2
months to 13 years (mean, 3 years) in seven boys and four girls. Time from injury
to esophageal replacement was 12 months to 14 years (mean, 5 years). All 11 had
multiple dilations before the replacement. Two had injury and scarring of the
epiglottis and larynx that required pharyngeal reconstruction and tracheostomy
before replacement. Nine patients underwent reconstruction with a gastric tube
anastomosed to the cervical esophagus, and the other two had an interposition
with an intrathoracic anastomosis. Eight tubes were antiperistaltic and three
isoperistaltic. Seven tubes were placed in the retrosternal space, three were
transthoracic, and one was subcutaneous. Six tubes were completed in two stages
and five in a single stage. RESULTS: Nontube complications were wound infection
(n = 2), perforation (n = 2), paralyzed hemidiaphragm (n = 1), and recurrent
laryngeal nerve injury requiring tracheostomy (n = 1). Tube complications were
anastomotic leak (n = 9), stricture (n = 8), anastomotic resection (n = 3), ulcer
(n = 1), and perforation (n = 1). Six required posttube multiple dilations for
several years including self-bouginage (n = 2). All learned to swallow and eat
initially with minimal aspiration; only one remains on tube feed supplements.
Long-term follow-up (3 to 30 years) includes nine eating normally and not
requiring dilations (the tracheostomy boy has chronic lung disease), one lost to
follow-up after 1 year, and one death from tube hemorrhage 2 months after
operation. CONCLUSION: Children with caustic injury to the upper aerodigestive
system can undergo gastric tube replacement with good results. The majority of
the problems relate to the esophagogastric tube anastomosis.
PMID- 9766356
TI - An evidenced-based clinical pathway for acute appendicitis decreases hospital
duration and cost.
AB - BACKGROUND/PURPOSE: In the pediatric population, appendicitis remains the most
common surgical emergency encountered. The purpose of this study was to determine
the impact of an evidence-based clinical pathway for acute appendicitis on
patient care as well as hospital and home care costs at the authors' pediatric
institution. METHODS: A prospective evaluation was conducted of an appendicitis
clinical pathway (June 1996 through November 1996) compared with historical
control patients (June 1994 through November 1994) not cared for by the pathway.
RESULTS: Data (average +/- SD) for 120 pathway (P) patients were compared with
122 control (C) patients. Age (11.5 +/- 3.6 years for C v 11.2 +/- 3.9 years for
P), rates of negative appendectomy (12.3% for C v 9.2% for P) and perforation
(26.2% for C v 18.3% for P) were similar. Pathway patients with nonperforated
appendicitis were more often discharged from the hospital within 24 hours (48%
for C v 67% for P; P = .014) with lower hospital costs ($4,095 +/- $1,280 for C v
$3,638 +/- $1,633 for P; P = .001). Pathway patients with perforated appendicitis
had shorter hospitalization (185.2 +/- 59 hours for C v 113 +/- 44 hours for P; P
= .0001) and lower hospital costs ($11,175 +/- $3,893 for C v $7,823 +/- $2,366
for P; P = .0001). CONCLUSION: An evidence-based appendicitis pathway decreased
duration of hospitalization and cost without adversely affecting diagnosis or
therapy. Clinical pathways for surgical diagnoses may prove useful as a means to
minimize costs without compromising patient care.
PMID- 9766355
TI - Pulmonary arterioles from rats with congenital diaphragmatic hernias are
hypoplastic but not hyperresponsive.
AB - BACKGROUND: Infants born with congenital diaphragmatic hernias (CDH) frequently
die as a result of pulmonary hypertension and persistent fetal circulation. The
pulmonary vessels of infants with CDH have decreased total cross-sectional area,
increased muscle content, and muscularization of intra-acinar arterioles that are
normally not muscularized. These structural alterations are believed to result in
exaggerated responses to normal vasoconstrictor stimuli. METHODS: The authors
used the nitrofen-induced CDH model in rats to determine whether the
vasoconstrictor responses of pulmonary arterioles are exaggerated in this animal
model of CDH. The authors compared the responses of isolated third-generation
pulmonary arterioles from normal rats and from rats with nitrofen-induced CDH to
K+-induced depolarization, phenylephrine, angiotensin II, serotonin, and the
thromboxane A2 agonist, U46619. RESULTS: It was found that the intraluminal
diameter of third-generation pulmonary arterioles from CDH rats was significantly
less than in controls (129 +/- 5 micron v 152 +/- 9 micron, respectively). In
addition, the ratio of wall thickness to vessel internal diameter was increased
in the third-generation pulmonary arterioles of rats with nitrofen-induced CDH
(0.62 +/- 0.4 v 0.50 +/- 0.5 for controls). Responses to K+-induced
depolarization, phenylephrine, angiotensin II, serotonin, and U46619, however,
were not different for pulmonary arterioles from control and CDH rats.
CONCLUSION: These data suggest that the structural alterations of the pulmonary
vasculature observed in infants with CDH may not cause exaggerated
vasoconstrictor responses to normal vasoconstrictor stimuli.
PMID- 9766357
TI - Antenatally diagnosed surgical anomalies: the psychological effect of parental
antenatal counseling.
AB - BACKGROUND: Increasing numbers of infants have the diagnosis of a surgical
malformation made before birth. This allows (1) fetal intervention, (2) in utero
transfer and planned delivery in a surgical center, and (3) antenatal counseling
of likely prognosis and outcome. The aim of this study was to assess the
effectiveness of antenatal counseling in terms of the parental psychological
response. METHODS: Antenatal counseling by a pediatric surgeon and neonatal nurse
was given after ultrasound diagnosis of a fetal surgical malformation (eg,
gastroschisis, diaphragmatic hernia). Anxiety levels were measured using the
Spielberger State-Trait Anxiety Inventory, a tool used by psychologists to assess
the inherent level of anxiety, or Trait anxiety (STAI-T), and the current level
of anxiety, or State anxiety (STAI-S). RESULTS: Fifty six prospective mothers
filled out Spielberger questionnaires (subjects, n = 26; controls, n = 30).
Nineteen subjects' partners also completed questionnaires. There was no
significant difference in Trait anxiety scores between subjects and controls (41
[interquartile range, 30 to 511 v 38.5 [range, 32 to 47]; P = .58). There was no
significant correlation between maternal and paternal Trait anxiety (P = .11).
There was a significant reduction in State anxiety scores in both subject mothers
(49.5 [interquartile range, 27 to 73) v38 [range, 31 to 49]; P = .01) and fathers
(47 [interquartile range, 36 to 55] v 37 [interquartile range, 32 to 49]; P =
.006) after pediatric surgical consultation. CONCLUSION: Counseling by specialist
staff reduced levels of parental anxiety associated with the diagnosis of fetal
surgical malformation.
PMID- 9766358
TI - Correlation between Down's syndrome and malformations of pediatric surgical
interest.
AB - PURPOSE: This is a collaborative study carried out by Pediatric Surgeons of the
"G.D'Annunzio" University and the Regional Association of Down Children of
Abruzzo (Italy). METHODS: Data were collected of malformations combined with Down
Syndrome (DS) during a 10-year period in a population of defined age to look for
a possible improvement of the patients' life conditions. Reportedly, 50% of these
patients may reach an age of about 60 years. RESULTS: One hundred twenty-seven DS
subjects from this region were evaluated, 54% of whom had associated
malformations (13% cardiac, 41% extracardiac, and 13% both). Seventeen patients
of 53 underwent surgery for extracardiac malformations, with gastrointestinal
malformations prevailing. The largest number of DS babies were born from mothers
under 30 years of age; this is attributed to the largest birth rate and the least
prevention at this age. Mothers older than 38 years gave birth to DS babies with
the lowest rate of associated malformations. CONCLUSION: The role of the
pediatric surgeon in multidisciplinary assistance for DS patients is stressed.
PMID- 9766359
TI - Central venous catheter bloodstream infections in the neonatal intensive care
unit.
AB - PURPOSE: The goal of this study was to identify symptoms and signs related to
central venous catheter (CVC) bloodstream infections (BSI) in neonatal intensive
care unit (NICU) patients that would predict infection and to identify factors
that might influence CVC longevity. METHODS: This was a retrospective cohort
study evaluating 268 lines representing a total of 5,212 CVC days placed in 157
NICU patients over 29 months by the pediatric surgery and neonatology services at
one children's hospital. Centers for Disease Control (CDC) criteria were used to
determine laboratory-confirmed BSI. Data were analyzed by univariate methods and
logistic regression and determined significant at the P less than .05 level.
RESULTS: Sixty-five lines (24%) from 54 patients had confirmed CVC BSI. Fever
(49%) and pulmonary dysfunction (30%) were the most common symptoms of CVC BSI.
Erythema or purulent discharge at the insertion site was found in only 20% of
cases. Staphylococcus epidermidis was the most common organism isolated. Factors
that significantly decreased the incidence of CVC BSI were increasing estimated
gestational age (EGA; P < .0013) attime of insertion, associated vancomycin use
at the time of catheter placement (P < .0057), and fewer days of catheter use (P
< .0291). There were no significant differences noted caused by line location or
catheter type. CONCLUSION: Fever and pulmonary dysfunction were the most common
signs of CVC BSI in neonates. Lower EGA and increased catheter duration were
significantly correlated with infection. The use of vancomycin concurrent with
catheter insertion was associated with a decreased incidence of CVC BSI,
howeverconcerns regarding the emergence of vancomycin-resistant organisms
preclude support of its use as a prophylactic agent.
PMID- 9766361
TI - Management of instrumental perforations of the esophagus occurring during
treatment of corrosive strictures.
AB - BACKGROUND: The initial symptoms of esophageal perforations (EP) may be subtle,
but the progression is very rapid, and the outcome may be disastrous unless the
diagnosis is made early and proper treatment is started immediately. METHODS:
Between 1976 and 1996, 1,249 patients with caustic esophageal burns were treated
at Ege University. The study group is composed of 52 patients with instrumental
ER Perforations occured during dilatation attempts of esophageal strictures.
Twelve patients were referred from other institutions after the occurrence of EP.
RESULTS: In two patients, emergency surgical repair of the perforation was
possible. Seventeen patients with unilateral and two patients with bilateral
empyema were treated by pleural drainages. Anterior retrosternal mediastinal
drainage was needed in one patient, and 11 patients required posterior
mediastinal drainages. Three patients were treated by both anterior and posterior
mediastinal drainage. Tracheoesophageal fistulas (TEF) developed in eight
patients immediately after a dilatation attempt. Seven of these patients required
esophageal replacement with colon to bypass the fistulas, and one patient in this
group healed spontaneously. EP healed in 42.5 +/- 49.4 days. Twelve (23%)
patients died of mediastinitis and sepsis. CONCLUSION: When EP is diagnosed and
treated with these methods, the mortality rate should approach zero.
PMID- 9766360
TI - Prehospital care and survival of pediatric patients with blunt trauma.
AB - BACKGROUND: The aim of this study was to compare the outcome of severe blunt
trauma in children receiving prehospital care from either physician-staffed
advanced life support (ALS) units, or from basic life support (BLS) units staffed
by emergency medical technicians. METHODS: The records of 288 children with
severe blunt trauma who required intensive care in the regional level 1 trauma
center or who died from their injuries were analyzed retrospectively. Patients
were excluded if resuscitation at the scene was not attempted, if the level of
prehospital care was unspecified, or if arrival at the level 1 trauma center was
delayed beyond 150 minutes. Seventy-two patients met the inclusion criteria of
BLS-, and 49 the criteria of ALS-prehospital care. RESULTS: A reduced mortality
rate (22.4% v 31.9%) was seen in the ALS group, which was more apparent in a
"salvageable but high-risk" subgroup, characterized by Glasgow Coma of Scale 4
through 8, Pediatric Trauma Score of 0 through 5, and Injury Severity Score (ISS)
of 25 through 49. However, a statistically significant difference was only seen
when trauma severity was evaluated by the ISS. CONCLUSION: An improved outcome in
children with severe blunt trauma has been demonstrated when prehospital care is
provided by physician-staffed ALS units compared with BLS units.
PMID- 9766362
TI - Early risk factors in pediatric renal transplantation at a single center.
AB - BACKGROUND/PURPOSE: Renal transplantation is the preferred treatment for renal
failure in childhood, but the incidence of graft failure is generally higher than
that in adult recipients. A single center was studied to determine if there were
any correctable factors that could contribute to graft failure. METHODS:
Recipient, donor, and perioperative factors were analyzed using standard
statistical tests in 59 pediatric renal transplants performed between 1992 and
1995 using standard cyclosporin-based immunosuppression. RESULTS: Three factors
were found to be significantly different between those recipients with good graft
function and those who either died or were returned to dialysis. Any history of
donor hypotension was a detrimental factor (P < .05, chi(2) test). In addition,
those with failed grafts were more likely to have received their grafts from
younger donors (P = .025, Mann Whitney U test). A third risk factor was a low
postoperative central venous pressure in those whose graft ultimately failed (P =
.0012, Mann Whitney U test). CONCLUSIONS: With a pediatric recipient who is
stable and has a low priority for a renal graft, small donors, particularly those
who have experienced hypotension, should be considered not suitable for
transplantation. The chances of a successful graft can be improved by good
communication between surgeon, pediatrician, and anesthetist. The importance of
maintaining a positive central venous pressure is emphasised.
PMID- 9766363
TI - Volvulus of the transverse colon in children.
AB - Volvulus of the transverse colon is extremely rare in children. A case report of
this unusual condition in a 9-year-old girl is presented together with a review
of the literature. The transverse colon volvulus was managed operatively by
detorsion. Four and half months later, she had a similar attack. Colonoscopic
detorsion was performed with elective resection of the transverse colon and
primary anastomosis. Recovery was uneventful. Possible factors of pathogenesis
are discussed, and an outline of diagnostic and therapeutic measures are
included.
PMID- 9766364
TI - Double-barrelled colovaginoplasty in a patient with cloacal exstrophy variant.
AB - Description of a new technique for combining colovaginoplasty with rectal pull
through.
PMID- 9766365
TI - In vivo karyotypic evolution with altered biological characteristics in a case of
neuroblastoma.
AB - Molecular and biological analyses of a neuroblastoma case in which the original
tumor contained a nodular region are described. No significant difference was
observed between the nodular and the surrounding tumor tissue with respect to
histopathologic examination, N-myc amplification, and trkA expression. However,
flow cytometric analysis demonstrated that the nodular region consisted of a
hypertetraploid clone, whereas the surrounding tissue mostly contained a
hyperdiploid clone. Chromosome analysis showed that each clone had a similar
chromosome acquisition pattern, suggesting that the hypertetraploid cells of the
nodular region arose from the hyperdiploid cells of the surrounding tissue.
Moreover, primary culture findings of the tumor cells showed that the responses
to nerve growth factor or retinoic acid were different between the two.
Collectively, this case suggests the possibility that neuroblastoma acquires
novel biological characteristics through karyotypic evolution in vivo.
PMID- 9766366
TI - Surgery for thoracic empyema concurrent with rupture of lung abscesses in a
child.
AB - The authors report surgical treatment for thoracic empyema concurrent with
rupture of lung abscesses and completely collapsed lung in a child. Right middle
lobectomy for ruptured abscess, debridement and closure with interrupted sutures
for another abscess in the lower lobe, and decortication were performed. Positive
pressure ventilation was needed to prevent reexpansion pulmonary edema because of
long-term collapsed lobes. The patient is doing well with no recurrent empyema or
thoracic deformity at 3 years postoperation.
PMID- 9766367
TI - Adenomyomatosis of the gallbladder in childhood.
AB - Adenomyomatosis of the gallbladder (ADMG) is defined as an acquired disease
characterized by localized or diffuse hyperplastic extensions of the mucosa into,
and often beyond, the thickened gallbladder muscular layer (Rokitansky-Aschoff's
sinuses). In recent years, attention has been drawn to its malignant potential.
The occurrence of ADMG has never been reported in children. The authors report
the case of a 5-year-old boy with symptomatic ADMG, who was successfully treated
by laparoscopic cholecystectomy.
PMID- 9766368
TI - Congenital lateral cervical cysts of infancy.
AB - The etiology of lateral cervical cysts in infancy is complex. The cysts are
congenital in origin and are derived from the third or fourth branchial
apparatus. The authors describe two cases of congenital lateral cervical cysts
with an internal opening in the pyriform sinus and possible origin in the third
branchial arch. The embryology, clinical presentation, and operative management
of this condition is reviewed.
PMID- 9766369
TI - Primary pneumococcal peritonitis complicated by exudative pleural effusion in an
adolescent girl.
AB - A healthy, young adolescent girl developed primary pneumococcal peritonitis, an
infection rarely reported in this age group in North America. Her course was
further complicated by exudative pleural effusion and pneumonia despite receiving
10 days of clindamycin therapy. Laparascopy proved useful in making the initial
diagnosis, but may have contributed to the pathogenesis of the pulmonary process.
Case presentation, management, and etiology are discussed.
PMID- 9766370
TI - Juvenile polyp in esophageal colon interposition.
AB - Esophageal polyps are rare in children, whereas colorectal juvenile polyps are
common. An 11-year-old boy with an esophageal colonic interposition for an
esophageal stricture secondary to caustic injury was found to have a polypoid
mass in the interposed colon. Fiberoptic endoscopic removal with diathermy was
performed. Histological examination confirmed it was a juvenile polyp. The
occurrence of a polyp in a colon removed from its natural location and serving a
different function suggests the possibility that an unknown factor produced by
colonic cells play a pivotal role in its development.
PMID- 9766371
TI - Colon perforation in hyperimmunoglobulin E syndrome.
AB - Colon perforation from hyperimmunoglobulin E syndrome is very rare, and only one
case has been reported in the English-language literature. Herein, the authors
report another case of colon perforation experienced in hyperimmunoglobulin E
syndrome. The patient was an 8-year-old girl with frequent infection, eczematoid
dermatitis, and an increased serum level of immunoglobulin E. During admission,
panperitonitis developed caused by colon perforation. Treatment was resection of
the perforated segment of the colon and a double-barrel colostomy. The patient
has been doing well 18 months after treatment.
PMID- 9766372
TI - Atresia of the appendix.
AB - A 4-day-old black male underwent laparotomy for intestinal obstruction. At
surgery, multiple jejunal atresias (type IV) of the jejunum were detected. As an
incidental finding, atresia of the appendix was also present. The jejunal atresia
was repaired, and resection of the tip of the cecal pole and atretic appendix was
performed. Gross and histological examination confirmed the presence of a type IV
atresia of the jejunum and a cordlike (type II) atresia of the appendix with
inflammatory changes in the tip of the appendix. The boy made an uneventful
recovery. Examination of all organ systems did not show any associated findings,
and the family history was unremarkable. To our best knowledge, this case
represents the first case of atresia of the appendix described in the literature.
PMID- 9766373
TI - Undescended testicle associated with spigelian hernia.
AB - The authors encountered a patient with a spigelian hernia (SH) and undescended
testicle (UDT), making the fourth reported case with this combination. This
patient provides further evidence that congenital SH predisposes neonates to UDT.
PMID- 9766374
TI - Spontaneous regression of tumoral calcinosis in an infant: a case report.
AB - A case of tumoral calcinosis presenting as a supraclavicular mass in an infant is
reported. After confirmation by incisional biopsy, the lesion spontaneously
resolved without further surgical or medical treatment. This phenomenon has not
been described previously in a child with this condition.
PMID- 9766375
TI - Fetus-in-fetu: a case report and review of the literature.
AB - A unique case of intraperitoneal fetus-in-fetu attached to an ovary is presented.
An asymptomatic newborn girl was found to have a mobile cystic mass in right side
of her abdomen. Radiological investigations showed fetus-in-fetu. During
laparotomy, an intraperitoneal fetus-in-fetu was found attached to right ovary
and vascular pedicle to ovarian vessels. Only 79 cases of fetus-in-fetu have been
reported, and this is the first such case attached to an ovary.
PMID- 9766376
TI - Acute scrotum: an exceptional presentation of acute nonperforated appendicitis in
childhood.
AB - Acute scrotum is an exceptional form of presentation of acute appendicitis in the
pediatric age group. Only 14 cases have been described in literature. The authors
report a case of an 8-year-old boy with a 12-hour history of right hemiscrotal
pain secondary to acute retrocecal nonperforated appendicitis. Surgical
exploration showed a patent "processus vaginalis."
PMID- 9766377
TI - Adenocarcinoma of the appendix in a child.
AB - Adenocarcinoma of the appendix is unusual at any age but occurs mostly in an
elderly population. The authors report a unique case presenting in a 10-year-old
child and emphasize the importance of subjecting all resected specimens to
histological examination.
PMID- 9766378
TI - Laparoscopic splenic cystectomy: a case report.
AB - Congenital epidermoid splenic cysts are very rare. They are known to become
symptomatic as a consequence of enlargement, hemorrhage, rupture, or infection.
Recent options in the treatment of splenic cysts have included percutaneous
drainage, partial splenectomy, or open splenic cystectomy. The authors present
the first report of a pediatric patient with a large epidermoid cyst of the
spleen treated by laparoscopic partial cyst excision and omental packing. Follow
up at 1 year confirms no recurrence. Laparoscopy provides a minimal access method
of obtaining pathological confirmation of diagnosis, reduction of cyst
complications, and a short hospital stay, while preserving splenic function.
PMID- 9766379
TI - Allantoic cyst and persistent urachal-allantoic communication: a rare umbilical
anomaly.
AB - True cysts of the umbilical cord are distinctly rare. A cyst lined by
uroepithelium is described in a newborn in whom the cyst communicated freely with
a patent urachal system. It is assumed that this most likely represents a remnant
cyst of the allantois--an anomaly not described previously.
PMID- 9766380
TI - An unusual case of esophageal atresia and double distal tracheoesophageal
fistula.
AB - This report describes a neonate with a very rare and an unusual variety of
esophageal atresia and tracheoesophageal fistula. The anomaly consisted of
esophageal atresia and double distal tracheoesophageal fistula. The two fistulae
as well as part of the distal esophagus were made up of tracheobronchial tissues.
The embryology of the anomaly is also discussed.
PMID- 9766381
TI - Venovenous extracorporeal membrane oxygenation in newborn infants using the
umbilical vein as a reinfusion route.
AB - PURPOSE: The authors report on four neonates treated with venovenous (VV)
extracorporeal membrane oxygenation (ECMO) using the umbilical vein as a
reinfusion route. METHODS: From 1994 to 1997, 26 instances VV-ECMO in neonates
have been carried out at our neonatal center for the treatment of severe
respiratory and cardiac failure. Among them, 22 patients could be treated with VV
ECMO mainly using 15F double-lumen catheter (DLC), adding the cephalic drainage
using another catheter. In the remaining four cases, however, attempts to insert
the DLC into the right internal jugular vein failed because the vein was too
small or technical problems. For such instances, two catheters were cannulated
into the right atrium and the cephalic portion of the right internal jugular
vein, respectively. These two venous catheters were connected to the drainage
route of ECMO circuit with a "Y" connector. Then, the umbilical vein was
cannulated with 10F or 8F catheter, which was connected to the reinfusion route
of ECMO to return the oxygenated blood to the infant. RESULTS: The median age at
which ECMO was initiated was 18 hours, and the median ECMO course was 72 hours.
The liver function tests were slightly and transiently worsened in two patients
during VV perfusion, (in one patient serum glutamic-oxaloacetic transaminase
[SGOT] elevated to 76 IU/L and serum glutamic-pyruvic transaminase [SGPT] to 49
IU/L, and in another patient SGOT elevated to 56 IU/L and SGPT remained in normal
range). Preumbilical cannula pressures were measured in two patients. In a
patient who used 10F umbilical cannula, the preumbilical maximum pressure was 43
mm Hg at 250 mL/min of ECMO flow. In another with an 8F catheter, it was 72 mm Hg
at 180 mL/min of ECMO flow. All of the patients survived without any neurological
complications. CONCLUSIONS: If the right internal jugular vein would not
accommodate the DLC, VV-ECMO using the umbilical vein as a infusion route could
be selected.
PMID- 9766382
TI - Two cases of torsion of the gallbladder diagnosed preoperatively.
PMID- 9766383
TI - Balloon extraction of esophageal foreign bodies in children.
PMID- 9766384
TI - Morphological substrates underlying opioid, epinephrine and gamma-aminobutyric
acid inhibitory actions in the rat locus coeruleus.
AB - The locus coeruleus (LC) has been implicated in attentional processes related to
orienting behaviors, learning and memory, anxiety, stress, the sleep-wake cycle,
and autonomic control, as well as to contributing to the affective state. Direct
activation of LC neurons causes desynchronization of the electroencephalogram,
suggesting that the LC is an important modulator of the behavioral state. The LC
has been an intensely studied neuronal system, as the physiology and pharmacology
of this nucleus is well understood. This is mainly because of the similarity in
neurochemical composition of LC cells which all contain norepinephrine in the
rat. However, the homogeneity in neurotransmitter content in LC neurons is
sharply contrasted by the heterogeneity of neurochemicals found in its afferent
processes. Among these are axon terminals that contain inhibitory and excitatory
amino acids, monoamines, and neuropeptides, many of which have been shown to
exert differential physiological effects on LC discharge activity. Although much
attention has focused on physiological activation of LC neurons, substantial
evidence indicates that diverse afferents prominently inhibit noradrenergic
cellular activity. Such inhibitory neurochemicals, which arise from local and
extrinsic sources, include gamma-aminobutyric acid (GABA) and epinephrine as well
as the neuropeptides methionine5-enkephalin and leucine5-enkephalin. Inhibitory
transmission in the LC has widespread implications for norepinephrine release at
diverse postsynaptic targets, and clinically useful pharmacological agents such
as clonidine, an alpha2 adrenergic receptor agonist that potently inhibits the
firing of LC neurons, alleviate some negative physical symptoms observed
following withdrawal from opiates. In the present review, the synaptic and
functional organization of selected inhibitory-type neurotransmitters in the LC
obtained from immunoelectron microscopic data will be discussed.
PMID- 9766385
TI - Angiotensin receptors in the nervous system.
AB - In addition to its traditional role as a circulating hormone, angiotensin is also
involved in local functions through the activity of tissue renin-angiotensin
systems that occur in many organs, including the brain. In the brain, both
systemic and presumptive neurally derived angiotensin and angiotensin metabolites
act through specific receptors to modulate many functions. This review examines
the distribution of these specific angiotensin receptors and discusses evidence
regarding the function of angiotensin peptides in various brain regions.
Angiotensin AT1 and AT2 receptors occur in characteristic distributions that are
highly correlated with the distribution of angiotensin-like immunoreactivity in
nerve terminals. Acting through the AT1 receptor in the brain, angiotensin has
effects on fluid and electrolyte homeostasis, neuroendocrine systems, autonomic
pathways regulating cardiovascular function and behavior. Angiotensin AT1
receptors are also found in many afferent and efferent components of the
peripheral autonomic nervous system. The role of the AT2 receptor in the brain is
less well understood, although recent knockout studies point to an involvement
with behavioral and cardiovascular functions. In addition to the AT1 and AT2
receptors, receptors for other fragments of angiotensin have been proposed. The
AT4 binding site, which binds angiotensin, has a widespread distribution in the
brain quite distinct from that of the AT1 and AT2 receptors. It is associated
with many cholinergic neuronal groups and also several sensory nuclei, but its
function remains to be determined. Our discovery that another brain-derived
peptide binds to the AT4 binding site in the brain and may represent the native
ligand is discussed. Overall, the distribution of angiotensin receptors in the
brain indicate that they play diverse and important physiological roles in the
nervous system.
PMID- 9766386
TI - Specificity of interleukin-1beta-induced changes in monoamine concentrations in
hypothalamic nuclei: blockade by interleukin-1 receptor antagonist.
AB - The purpose of this study was to examine specificity in the effects of
interleukin-1beta (IL-1beta) on monoamines in various areas of the hypothalamus.
Adult male rats were injected i.p. with saline or 2.5 or 5.0 microg of IL-1beta
or were pretreated with 500 microg of IL-1 receptor antagonist (IL-1ra) followed
5 min later by 5 microg of IL-1beta. The paraventricular nucleus (PVN), arcuate
nucleus (AN), median eminence (ME), and medial preoptic area (MPA) were
microdissected and analyzed for neurotransmitter concentrations by high
performance liquid chromatography with electrochemical detection (HPLC-EC). In
the PVN, IL treatment produced significant increases in the concentrations of
norepinephrine (NE), dopamine (DA), DA metabolite dihydroxyphenylacetic acid
(DOPAC), serotonin (5-HT), and its metabolite 5-hydroxyindoleacetic acid (5
HIAA). IL-1 treatment increased the concentrations of NE and DA in the AN but
only of NE in the ME, and it was without any effect in the MPA. Pretreatment with
IL-1ra completely blocked the IL-1 effects. It is concluded that IL-1 induces
highly specific changes in monoamine metabolism in the hypothalamus, and the
nature of these changes depends on specific hypothalamic nuclei.
PMID- 9766387
TI - Truncated green fluorescent protein mutants and their expression in Aplysia
neurons.
AB - We determined in detail the primary structure requirements for green fluorescence
of the jellyfish green fluorescent protein (GFP) and of its improved mutants
(S65T and 1167T). We performed a deletion mapping in combination with
fluorescence-activated cell sorting (FACS) and spectrofluorometry. This showed
that deletion of up to nine amino acids at the C-terminal end of GFP had no
deleterious effect on the fluorescent activity of GFP; in fact the deletion
increased intensity of fluorescence. Further truncation of up to 11 amino acids
resulted in partial impairment in maximal fluorescence. The GFP fluorescence was
completely disrupted when more than 12 amino acids were deleted out of the C
terminal. Truncated mutants or their fusion genes with lacZ emitted fluorescence
when plasmids encoding them were introduced by microinjection into Aplysia
neurons.
PMID- 9766389
TI - Suppressive effect of vagal afferents on the activity of the trigeminal spinal
neurons related to the jaw-opening reflex in rats: involvement of the endogenous
opioid system.
AB - The purpose of the present study is to test the hypothesis that via the
endogenous pain control system, vagal afferent input modulates the activity of
the trigeminal spinal nucleus oralis (TSNO) related to the tooth pulp (TP)-evoked
jaw-opening reflex (JOR). Extracellular single-unit recordings were made from 36
TSNO units responding to TP electrical stimulation with a constant temporal
relationship to a digastric electromyogram (dEMG) signal in 26 pentobarbital
anesthetized rats. The activity of 36 TSNO neurons and the amplitude of the dEMG
increased proportionally during 1.0-3.5 times the threshold for JOR. Some of
these neurons (4 out of 5) were also excited by chemical stimulation (bradykinin,
1-2 microl, 1 mM) of TP. In 31 out of 36 TSNO neurons (86%), their activities
during tooth pulp stimulation were suppressed by conditioning stimulation of the
right vagus nerve. The suppressive effect of vagal afferent stimulation occurred
at conditioning-test intervals of 20-150 ms after the onset of the stimulation,
and its maximal suppressive effect occurred at approximately 50 ms. The mean time
course of this suppressive effect paralleled that of the dEMG. After
administration of naloxone (0.5 and 1.0 mg/kg, i.v.), an opiate receptor blocker,
the suppressive effect on the activity of TSNO neurons (6 out of 8) was
significantly attenuated at the conditioning-test interval of 50 ms compared to
the control (p < 0.01). These results suggested that vagal afferent input
inhibits nociceptive transmission in the TSNO related to TP-evoked JOR and this
inhibitory effect may occur via the endogenous opioid system in rats.
PMID- 9766388
TI - Propriospinal neurons in the C1-C2 spinal segments project to the L5-S1 segments
of the rat spinal cord.
AB - Physiological studies indicate that neurons in the upper cervical spinal cord
have descending projections to the lumbosacral spinal cord and mediate inhibition
of dorsal horn neurons activated from afferent input. In the present study,
retrograde tracing techniques were used to examine the distribution of
propriospinal neurons in C1-C2 spinal segments that project to lumbosacral spinal
segments. Fluorogold or horseradish peroxidase were injected unilaterally or
bilaterally into the L5-S1 spinal segments. After 2-4 days, rats were perfused
with fixative and C1-C2 spinal segments were processed for retrograde labeling.
Numerous neurons were found in the C1-C2 segments. In unilaterally and
bilaterally injected rats, retrogradely labeled neurons were located on both the
ipsilateral and contralateral sides. Retrogradely labeled neurons were located in
the following locations: lateral cervical and spinal nuclei, nucleus proprius,
ventral horn and the central gray region (area X). These studies demonstrate a
descending projection from C1-C2 segments to the lower lumbar and sacral spinal
cord. We hypothesize that many of these C1-C2 propriospinal neurons are important
in modulating responses of spinal neurons at lower segmental levels to various
peripheral stimuli.
PMID- 9766390
TI - Behavioural and hormonal effects of restraint stress and formalin test in male
and female rats.
AB - The formalin test was used to measure the analgesia induced by restraint in male
and female rats. Animals were restrained for 30 min or left undisturbed in their
cage and then (1) killed immediately to collect blood for hormonal
determinations; or (2) subcutaneously injected with formalin in the hind paw (or
sham-injected), introduced to an open field for recording of behaviour, and
killed at the end of this procedure. In both experiments, corticosterone was
found to be higher in females. In Experiment 1, the ability of restraint to be
stressful was confirmed by the increase in corticosterone in both sexes and by
the decrease of testosterone in males. In Experiment 2, restraint-treatment
induced a reduction in licking and flexing that was limited to the second phase.
The reduction occurred in different periods and to a different degree in the two
sexes; it was greater in females. Spontaneous behaviours showed sex differences
in restraint-treated but not in formalin-treated animals. The results show that
the hormonal effects observed after restraint are not present after the formalin
test and that the marked analgesia observed with phasic painful stimuli does not
occur with a longer-lasting one such as that induced by formalin, after which
only partial and short-lasting effects were observed.
PMID- 9766391
TI - Impaired arterial baroreflex regulation of heart rate after blockade of P2
purinoceptors in the nucleus tractus solitarius.
AB - Activation of P2x-purinoceptors in the nucleus tractus solitarius (NTS) via
microinjection of ATP mimics baroreflex responses (bradycardia, hypotension);
however, the physiological role of these receptors in cardiovascular control
remains unclear. We tested whether blockade of these receptors attenuates
arterial baroreflex control of heart rate (HR). Baroreflex-induced changes in HR
(via graded i.v. infusion of phenylephrine and nitroprusside) were observed in
seven alpha-chloralose/urethane anesthetized male Sprague-Dawley rats before and
after microinjection of the purinergic P2 receptor antagonist suramin (0.5 nmol
in 50 nL) into the subpostremal NTS. Before suramin, typical baroreflex changes
in HR were observed (maximum gain, Gmax = 2.94 +/- 0.54 bpm/mmHg). Suramin
markedly impaired baroreflex-induced changes in HR (gain = 0.02 +/- 0.08 and 0.18
+/- 0.09 bpm/mmHg for increases and decreases in mean arterial blood pressure,
respectively); however, after 90-130 min, HR and baroreflex reactivity returned
to control levels. Microinjections of vehicle into the same area did not alter
baroreflex function. In addition, suramin did not alter the depressor responses
to microinjections of glutamate into the same site of the NTS. We conclude that
normal P2x-purinoceptor function in subpostremal NTS may be necessary for
baroreflex regulation of HR.
PMID- 9766392
TI - Effects of brain testosterone implants on appetitive and consummatory components
of male sexual behavior in Japanese quail.
AB - Aromatization of testosterone (T) into an estrogen is necessary for the
activation of consummatory and appetitive sexual behavior in male Japanese quail.
T action within the medial preoptic nucleus (POM) is necessary and sufficient to
activate consummatory behavior, and some evidence suggests that POM might be
involved in the control of appetitive behavior, but other brain regions, such as
the bed nucleus of the stria terminalis (BST), an area that contains a dense
population of aromatase-immunoreactive neurons, are also likely to be involved.
This study was performed to assess the effects of stereotaxic T implants
targeting either the POM or the BST on the activation of both components of
sexual behavior in castrated male quail. Appetitive sexual behavior was measured
by an acquired social proximity response in which a male will approach a window
providing visual access to a female after the window has been repeatedly paired
with physical access to a female and the possibility to freely interact with her.
Rhythmic cloacal sphincter movements that are produced by the male when given
visual access to a female were used as another measure of appetitive sexual
behavior that does not appear to depend on sexual learning. The experiments
confirmed that copulation is necessary for males to develop the social proximity
response that is used to measure the appetitive sexual behavior. T implants in
the POM activated both components of sexual behavior, suggesting that these
components cannot be completely dissociated. In contrast, T implants located
within the BST did not affect either component, but because implants in the BST
did not activate copulatory behavior, these results do not preclude a role for
BST in the expression of a previously acquired appetitive sexual behavior.
PMID- 9766393
TI - Role of opioidergic and monoaminergic neurotransmission in the GnRH release
mechanism of EBP-primed OVX rats.
AB - We examined the effect of intracerebroventricular (i.c.v.) administration of mu
opioid agonist, morphine, and its antagonist naloxone followed by morphine on the
activities of monoamine-metabolizing enzymes, namely tyrosine hydroxylase (TH)
and monoamine oxidase (MAO) along with adenosinetriphosphatase (Na+, K+ -ATPase),
the enzyme responsible for the maintenance of ionic gradients across the
membrane, in seven discrete regions of brain from estrogen- and progesterone
primed ovariectomized rats. TH activity decreased after morphine treatment in
some areas such as the median eminence-arcuate region (ME-ARC), the amygdala, and
the thalamus, showing statistically significant change. MAO activity increased in
all the areas studied, but more appreciable change was observed in medial
preoptic area (mPOA), the ME-ARC region, and the cortex. Pronounced increase in
Na+, K+ -ATPase enzyme activity was observed after the drug treatment. Naloxone
given prior to morphine injection resulted in recovery of the enzyme activities
in most of the areas studied. Our study may provide insights into the precise
opioidergic modulation of gonadotropin releasing hormone (GnRH) release
mechanisms through the involvement of monoaminergic system, elucidating the basis
of various neuronal dysfunctions and their management in opioid addicts.
PMID- 9766394
TI - Tyrosine phosphorylation is increased in the rat hippocampus during the status
epilepticus induced by pilocarpine.
AB - Phosphorylation of tyrosine residue in proteins is an important modulatory
process for membrane transduction and cell signaling and for several cellular
functions. The concentration and distribution of phosphotyrosine proteins were
analyzed in the hippocampi of rats in the model of epilepsy induced by
pilocarpine using Western blotting and immunohistochemistry. The concentration of
several phosphotyrosine proteins increased during status epilepticus. During the
seizure-free period and the chronic period of this epilepsy model, the hippocampi
of rats did not exhibit changes in the expression of these proteins.
Immunohistochemistry showed an increased immunoreactivity throughout the
hippocampal formation of rats 1 h after status epilepticus that was acutely
induced by pilocarpine. Animals killed after 3 h of status epilepticus showed an
increased expression of phosphotyrosine in the hippocampal hilus and CA3 regions.
After 5 h of status epilepticus, phosphotyrosine immunoreactivity persisted only
in the CA3 region. After 12 h of status epilepticus, the hippocampal formation
exhibited a normal phosphotyrosine immunostaining, showing that the increased
expression of these proteins is related to the acute phase and that several
intracellular events could undergo modifications during the status epilepticus
induced by pilocarpine.
PMID- 9766395
TI - Long-lasting structural changes in CA3 hippocampal and layer V motor cortical
pyramidal neurons associated with self-stimulation rewarding experience: a
quantitative Golgi study.
AB - Self-stimulation (SS) rewarding experience induced structural changes in CA3
hippocampal and layer V motor cortical pyramidal neurons in adult male Wistar
rats has been demonstrated. In the present study, whether these structural
changes are transient or of a permanent nature was evaluated. Self-stimulation
experience was provided for 1 h daily over a period of 10 days through
bilaterally implanted bipolar electrodes in the lateral hypothalamus and the
substantia nigra-ventral tegmental area. Following 10 days of SS experience, the
rats were sacrificed after an interval of 30 and 60 days for the quantitative
analysis of the dendritic morphology in Golgi stained CA3 hippocampal and layer V
motor cortical pyramidal neurons. The results revealed a significant increase in
the dendritic branching points and intersections in apical and basal dendrites in
both types of neurons in 30 days post-SS group compared to sham control. The
total number of apical and basal dendrites were significantly increased in both
30 and 60 days post-SS groups of rats. This study suggests that SS experience
induced structural changes are sustainable, even in the absence of rewarding
experience.
PMID- 9766396
TI - Zinc transport from the striatum and substantia nigra.
AB - 65Zn was unilaterally injected into the striatum or substantia nigra of rats to
see the transport of intracerebral zinc (Zn). In the case of intrastriatal
injection, 65Zn was densely distributed in the ipsilateral medial forebrain
bundle (MFB) and the substantia nigra. On unilateral colchicine injection into
the MFB, 65Zn distribution in the ipsilateral substantia nigra decreased
significantly compared to that of the contralateral one after 65Zn injection into
the bilateral striata. These results suggest the presence of axonal transport of
65Zn taken up by striatonigral gamma-aminobutyric acid (GABA)-ergic and/or
nigrostriatal dopaminergic neurons. On the other hand, in the case of intranigral
injection, 65Zn was distributed in the ipsilateral MFB, striatum, globus
pallidus, pontine reticular nuclei, and pontine nuclei. 65Zn distribution in the
pons 1 day after intranigral injection was very similar to that 6 days after
intrastriatal injection, suggesting that, in the case of intrastriatal injection
of 65Zn, nigral 65Zn, which was transported anterogradely and/or retrogradely
from the striatum, was transported to the postsynaptic neurons through the
synapse and then transported to the pons.
PMID- 9766397
TI - Auditory cortical projections to the cat inferior colliculus.
AB - The projection from 11 auditory cortical areas onto the subdivisions of the
inferior colliculus was studied in adult cats by using two different anterograde
tracers to label cortico-collicular (CC) axon terminals. The main results were
that: 1) a significant CC projection arose from every field; 2) the principal
inferior collicular targets were the dorsal cortex, lateral nucleus, caudal
cortex, and intercollicular tegmentum, with only a sparse projection to the
central nucleus; 3) the input was usually bilateral, with the ipsilateral side by
far the most heavily labeled, and the contralateral projection was a symmetrical
subset of the ipsilateral input; 4) the CC system is both divergent and
convergent, with single cortical areas projecting to six or more collicular
subdivisions, and each auditory midbrain subdivision receiving a convergent
projection from two to ten cortical areas; 5) cortical areas devoid of tonotopic
organization have topographic projections to collicular target nuclei; 6) the
heaviest CC projection terminated in the caudal half of the inferior colliculus;
and finally, 7) the relative strength of the cortico-collicular labeling was far
less than that of the corresponding corticothalamic projection in the same
experiments. The CC system is strategically placed to influence both descending
and ascending pathways arising in the inferior colliculus. Nuclei that
participate in the premotor system, like the inferior collicular subdivisions
that project to the pons, receive substantial corticofugal input. Both the dorsal
(pericentral) and the lateral (external) nuclei of the inferior colliculus
project to parts of the medial geniculate body whose closest auditory
affiliations are with non-tonotopic cortical regions involved in higher order
auditory perception. The cortico-collicular system may link brainstem and
colliculo-thalamic circuits to coordinate premotor and perceptual aspects of
hearing.
PMID- 9766398
TI - Temporal and spatial patterns of c-fos mRNA induced by intravenous interleukin-1:
a cascade of non-neuronal cellular activation at the blood-brain barrier.
AB - Brain cells responsive to a peripheral immune challenge, identified by in situ
hybridization of c-fos mRNA following intravenous administration of the
proinflammatory cytokine interleukin-1beta (IL-1) or sterile saline, were
investigated at 0.5, 1, and 3 hours postinjection in rats. Doses of IL-1 ranged
from 0.05 to 10 microg/kg; induction of c-fos mRNA occurred at > or = 0.5 pg/kg.
The majority of IL-1-induced c-fos mRNA-positive cells were non-neuronal cells
located in barrier regions of the brain. The cells became radiolabeled in two
separate but related spatiotemporal patterns. The first pattern, occurring at 0.5
hour, was characterized by c-fos mRNA labeling of cells of the outer meninges
(mainly arachnoid), blood vessels (arteries, veins, and capillaries), and choroid
plexus. This activation pattern disappeared at 1 hour. At 3 hours, a second
activation pattern appeared in cells located just inside the now quiescent
barrier cells. In addition, the circumventricular organs each showed
characteristic spatiotemporal labeling patterns resulting from successive
activation of specific cell types, with a general spread of activation directed
away from the circumventricular organs over time. At 3 hours post IL-1, c-fos and
glial fibrillary acidic protein (GFAP) mRNAs showed colocalization in the arcuate
nucleus/median eminence/glia limitans region. We propose that the first wave of
activation is elicited by blood-borne immune signals, but the second wave is
caused by molecules generated within the first set of activated cells. The
transduced signal appears to propagate to neighboring receptive cells by
extracellular diffusion. In this manner, blood-brain barrier cells can transduce
peripheral IL-1 signals in widespread areas of the brain, although the
circumventricular organs may be the most effective loci for signal transduction.
PMID- 9766399
TI - Timing and origin of the first cortical axons to project through the corpus
callosum and the subsequent emergence of callosal projection cells in mouse.
AB - A precise knowledge of the timing and origin of the first cortical axons to
project through the corpus callosum (CC) and of the subsequent emergence of
callosal projection cells is essential for understanding the early ontogeny of
this commissure. By using a series of mouse embryos and fetuses of the hybrid
cross B6D2F2/J weighing from 0.36 g to 1.0 g (embryonic day E15.75-E17.25), we
examined the spatial and temporal distribution of callosal projection cells by
inserting crystals of the lipophilic dye (DiI: 1,1'-dioctadecyl-3,3,3',3'
tetramethylindocarbocyanine perchlorate) into the contralateral white matter just
lateral to the midsagittal plane. Around 0.4 g or E15.8, retrogradely labeled
cells were found restricted to a discrete cluster continuously distributed from
the most ventral part of presumptive cingulate cortex to the hippocampus. During
subsequent development, however, the tangential distribution of these labeled
cells in ventromedial cortex did not extend further dorsally, and in fetuses
where the CC became distinct from the hippocampal commissure (HC), labeled axons
of cells in the ventral cingulate cortex were observed to intersect the callosal
pathway and merge with labeled axons of the HC derived from cells in the
hippocampus. The first cortical axons through the CC crossed the midline at about
0.64 g or E16.4, and these axons originated from a scattered neuronal population
in the dorsal to lateral part of the presumptive frontal cortex. The earliest
callosal cells were consistently located in the cortical plate and showed an
immature bipolar appearance, displaying an ovoid- or pearl-shaped perikaryon with
an apical dendrite coursing in a zig-zagging manner toward the pial surface and a
slender axon directed toward the underlying white matter. Callosal projection
cells spread progressively with development across the tangential extent of the
cerebral cortex in both lateral-to-medial and rostral-to-caudal directions. In
any cortical region, the first labeled cells appeared in the cortical plate and
their number in the subplate was insignificant compared to that in the cortical
plate. Thus, these results clarify that the CC is pioneered by frontal cortical
plate cells, and the subsequent ontogeny of callosal projection cells proceeds
according to the gradient of cortical maturation.
PMID- 9766400
TI - Noradrenergic system of the zebra finch brain: immunocytochemical study of
dopamine-beta-hydroxylase.
AB - Oscine birds are among the few animal groups that have vocal learning, and their
brains contain a specialized system for song learning and production. We describe
here the immunocytochemical distribution of dopamine-beta-hydroxylase (DBH), a
noradrenergic marker, in the brain of an oscine, the zebra finch (Taeniopygia
guttata). DBH-positive cells were seen in the locus coeruleus, the nucleus
subcoeruleus ventralis, the nucleus of the solitary tract, and the caudolateral
medulla. Immunoreactive fibers and varicosities had a much wider brain
distribution. They were particularly abundant in the hippocampus, septum,
hypothalamus, area ventralis of Tsai, and substantia nigra, where they formed
dense pericellular arrangements. Significant immunoreactivity was observed in
auditory nuclei, including the nucleus mesencephalicus lateralis pars dorsalis,
the thalamic nucleus ovoidalis, field L, the shelf of the high vocal center
(HVC), and the cup of the nucleus robustus archistriatalis (RA), as well as in
song control nuclei, including the HVC, RA, the lateral magnocellular nucleus of
the anterior neostriatum, and the dorsomedial nucleus (DM) of the intercollicular
complex. Except for the DM, DBH immunoreactivity within song nuclei was
comparable to that of surrounding tissues. Conspicuously negative were the lobus
paraolfactorius, including song nucleus area X, and the paleostriatum. Our
results are in agreement with previous studies of the noradrenergic system
performed in nonoscines. More importantly, they provide direct evidence for a
noradrenergic innervation of auditory and song control nuclei involved in song
perception and production, supporting the notion that noradrenaline is involved
in vocal communication and learning in oscines.
PMID- 9766401
TI - GABA, GABA transporters, GABA(A) receptor subunits, and GAD mRNAs in the rat
parabrachial and Kolliker-Fuse nuclei.
AB - In the present study, we investigated the key molecules that determine gamma
aminobutyric acid (GABA)ergic signal transduction in the parabrachial/Kolliker
Fuse complex (PB/KF) by means of immunocytochemistry and in situ hybridization.
Our data demonstrate a dense plexus of GABA-immunoreactive (-ir) varicosities
throughout the nuclei of the PB and the KF. The number of neurons expressing
GAD65 or GAD67 mRNA was fairly low in the PB, whereas caudally in the KF an
accumulation of GAD-expressing neurons was observed. The GABA transporter-3 (GAT
3) was detected in all parts of the PB/KF, whereas immunolabeling for GAT1 was
not observed. All nuclei of the PB and the KF exhibited immunoreactivity for the
gamma2-, alpha2-, and alpha3-subunits of the GABA(A) receptor. Gamma2-ir was
strong and similar in all PB/KF nuclei. In contrast, alpha2-labeling was
particularly intense in the superior lateral PB, and alpha3-labeling was most
prominent in the external lateral and external medial PB, compared with the
remaining nuclei. With respect to the subcellular localization, we found gamma2
ir in cell bodies and higher order dendrites, whereas alpha2- and alpha3-ir was
predominantly found in cell bodies. Immunolabeling for the beta2/3- and the
alpha1-subunit was seen in cell bodies and presumed dendritic profiles. The
staining intensity was strongest in the dorsal lateral PB. Most importantly, the
external lateral PB and the waist area were totally devoid of beta2/3- and alpha1
ir. Our data suggest that neural processing in the PB/KF is under a strong
GABAergic inhibition that is apparently mediated by different types of GABA(A)
receptors in functionally different pathways through the PB/KF.
PMID- 9766402
TI - Differential regulation of ciliary neurotrophic factor receptor-alpha expression
in all major neuronal cell classes during development of the chick retina.
AB - Ciliary neurotrophic factor (CNTF) exerts a multiplicity of effects on a broad
spectrum of target cells, including retinal neurons. To investigate how this
functional complexity relates to the regulation of CNTF receptor alpha (CNTFR
alpha) expression, we have studied the developmental expression of the receptor
protein in chick retina by using immunocytochemistry. During the course of
development, the receptor is expressed in all retinal layers, but three levels of
specificity can be observed. First, the expression is regulated temporally with
immunoreactivity observed in ganglion cells (embryonic day 8 [E8] to adult),
photoreceptor precursors (E8-E12), amacrine cells (E10 to adult), bipolar cells
(E12-E18), differentiated rods (E18 to adult), and horizontal cells (adult).
Second, expression is restricted to distinct subpopulations of principal retinal
neurons: preferentially, large ganglion cells; subpopulations of amacrine cells,
including a particular type of cholinergic neuron; a distinctly located type of
bipolar cell; and rod photoreceptors. Third, expression exhibits subcellular
restriction: it is confined largely to dendrites in mature amacrine cells and is
restricted entirely to outer segments in mature rods. These data correlate with
CNTF effects on the survival of ganglion cells and mature photoreceptors, the in
vitro differentiation of photoreceptor precursors and cholinergic amacrine cells,
and the number of bipolar cells in culture described here or in previous studies.
Thus, our results demonstrate an exceptional degree of complexity with respect to
the regulation of neuronal CNTFR alpha expression in a defined model system. This
suggests that the same signaling pathway is used to mediate a variety of
regulatory influences, depending on the developmental stage and cell type.
PMID- 9766403
TI - Preprocholecystokinin mRNA-expressing neurons in the rat parabrachial nucleus:
subnuclear localization, efferent projection, and expression of nociceptive
related intracellular signaling substances.
AB - The pontine parabrachial nucleus (PB) is a major target for ascending fibers from
nociresponsive dorsal horn neurons. Several different neuropeptides have been
identified in the PB. By using double-labeling methods that combine in situ
hybridization histochemistry with retrograde tract tracing and
immunohistochemistry, we have examined the subnuclear localization of
preprocholecystokinin mRNA (ppCCK)-containing neurons, investigated their
efferent projection, and analyzed their expression of intracellular signaling
substances that may be of importance for nociceptive processing. The results show
that neurons containing ppCCK are preferentially localized to the superior
lateral subnucleus (PBsl), whereas other subnuclei, such as the dorsal lateral,
external lateral, central lateral, and ventral lateral subnuclei, and the
Kolliker-Fuse nucleus, contain only moderate to small numbers of such neurons.
Injections of the retrograde tracer cholera toxin subunit b into the ventromedial
hypothalamus demonstrated that ppCCK-containing neurons in PBsl were projection
neurons. Following nociceptive stimulation, the ppCCK-containing neurons
expressed FOS protein as well as phosphorylated cyclic AMP-responsive element
binding protein (CREB). In addition, Ca2+/calmodulin-dependent kinase II (CaMKII)
was heavily and rather selectively expressed in PBsl and was co-localized to
ppCCK-containing neurons. These observations show that nociceptive stimuli
activate a cholecystokinin pathway from the parabrachial nucleus to the
ventromedial hypothalamus that may be important for homeostatic responses to
tissue damage, and point to a putative intracellular route for Ca2+-mediated FOS
transcription via CaMKII and CREB for the regulation of ppCCK transcription.
PMID- 9766404
TI - Thalamocortical connections of the parabelt auditory cortex in macaque monkeys.
AB - The auditory cortex of macaque monkeys contains a core of primary-like areas
surrounded by a narrow belt of associated fields that encompass much of the
superior temporal plane in these animals. Adjacent to the lateral belt on the
superior temporal gyrus is a parabelt region that contains at least two
subdivisions (rostral and caudal). In a previous study (Hackett et al. [1998] J.
Comp. Neurol. 394:475-495), we determined that the parabelt has topographic
connections with the belt areas surrounding the core, but minimal connections
with the core itself. In this study, we describe the thalamocortical connections
of the parabelt auditory cortex based on multiple injections of neuronal tracers
into this region in each of five macaque monkeys. Injections confined to the
parabelt labeled large numbers of neurons in the dorsal (MGd) and magnocellular
(MGm) divisions of the medial geniculate complex (MGC), suprageniculate (Sg),
limitans (Lim), and medial pulvinar (PM) nuclei. Only when injections encroached
on the lateral belt cortex were substantial numbers of labeled neurons found in
the ventral (MGv) division of the MGC, consistent with the absence of significant
connections between the parabelt and core fields. The rostrocaudal topography of
the parabelt region was maintained in the thalamocortical connections, supporting
the parcellation of this region of cortex. The results suggest that the parabelt
region represents a third level of auditory cortical processing, which is not
influenced by direct inputs from primary cortical or subcortical auditory
structures.
PMID- 9766405
TI - Neurogenesis and migration of receptor neurons in the vomeronasal sensory
epithelium in the opossum, Monodelphis domestica.
AB - The sensory epithelium of the vomeronasal organ (VNO) contains primary
chemosensory receptor neurons that project to the accessory olfactory bulb (AOB).
In the present study, neurogenesis and cell migration in the sensory epithelium
of the VNO were analyzed in opossums (Monodelphis domestica) by using
bromodeoxyuridine (BrdU) labeling. 1) In the VNO of normal adult opossums, BrdU
labeled a small number of cells localized in the basal region of the sensory
epithelium. After 1 or 2 weeks of survival, the labeled cells appeared in the
receptor cell layers and became receptor neurons, as indicated by coexpression of
the G proteins G(i alpha2) or G(o alpha). 2) In the VNO in which the receptor
neurons had been destroyed by removing the AOB, the number of BrdU-labeled cells
in the reconstituting sensory epithelium was greatly increased compared with that
in the intact VNO. The labeled cells were also located in the basal region of the
sensory epithelium. 3) In the developing VNO (at postnatal day 10), more cells in
the basal region of the sensory epithelium were labeled than in the adult VNO,
indicating rapid cell proliferation; and there appeared to be more labeled cells
in the basal region near the margins of the sensory epithelium where it meets the
nonsensory epithelium. These observations demonstrate that, in the opossum VNO,
there is a population of proliferating cells in the basal region close to the
basal lamina in the sensory epithelium. The newly generated neurons in the basal
region migrate vertically into the receptor cell layer.
PMID- 9766406
TI - Editorial: The jargonic disaster: or whom* wrote that note? 1985.
PMID- 9766407
TI - Mid-trimester emergent cerclage: a ten year single institution review.
AB - OBJECTIVE: To evaluate clinical factors associated with both time gained in utero
and gestational age at delivery in patients undergoing placement of emergent
cerclages. STUDY DESIGN: Retrospective chart review of 75 patients who underwent
nonprophylactic cerclages from 1984 to 1994 at Thomas Jefferson University
Hospital was performed. Clinical variables evaluated included gestational age at
cerclage, gestational age at delivery, cervical dilation at presentation, and
presence or absence of bulging membranes on admission. Presence or absence of
clinical symptoms at presentation or historic risk factors for incompetent cervix
were also noted. Noncontinuous data were analyzed using chi2 or Fisher's exact
test; continuous data were compared with either Student's t or Mann-Whitney U
tests. RESULTS: The mean gestational age at time of cerclage placement was 19.1
+/- 3.8 weeks, with a median of 12 weeks gained in utero. Overall, 65% of
patients delivered at > or =28 weeks, with 49% delivering at > or =34 weeks.
Patients with bulging membranes were more likely to be >2 cm dilated (58% vs. 0%;
p < 0.001) and to present at > or =20 weeks gestational age (69% vs. 28%; p <
0.001). They also gained less time after cerclage placement (median 6.4 vs. 17.0
weeks; p < 0.001) and were less likely to reach either 28 weeks (44% vs. 85%; p <
0.001) or 34 weeks (31% vs. 67%; p = 0.004) at delivery. CONCLUSION: The presence
of bulging membranes or advanced dilation at presentation was associated with
lower cerclage-to-delivery intervals as well as a lower chance of reaching 28
weeks of gestation.
PMID- 9766408
TI - The association of aneuploidy and unexplained elevated maternal serum alpha
fetoprotein.
AB - OBJECTIVE: The purpose of this study was to examine fetal chromosomal
abnormalities in pregnancies complicated by unexplained elevated maternal serum
alpha-fetoprotein (MSAFP). STUDY DESIGN: We reviewed, using a computerized
database, 58,162 obstetrical ultrasounds that were performed for various
indications. Fetuses with MSAFP multiples of the median (MOM) > or = 2.5 and
normal extensive ultrasounds were identified. Maternal demographic data and fetal
karyotype were obtained. RESULTS: Seven hundred eighty-nine patients received
ultrasounds for evaluation of elevated MSAFP. Of the 595 patients with normal
scans, 195 (32.8%) underwent amniocentesis and cytogenetic evaluation. Two
chromosomal abnormalities were detected (1.0%), including an inversion and a
balanced translocation. CONCLUSION: The two karyotypic abnormalities identified
in our study consisted of structural rearrangements. Patients undergoing
karyotype analysis for unexplained elevated MSAFP should be counseled that the
types of aneuploidy detected under this circumstance differ from those associated
with advanced age and specific fetal anomalies (trisomy and triploidy).
PMID- 9766409
TI - Impact of the perception of viability on resource allocation in the neonatal
intensive care unit.
AB - OBJECTIVE: To understand how neonatologists' perceptions of viability impact
their willingness to recommend or provide medical interventions for infants born
at 23 to 24 weeks' gestation. STUDY DESIGN: A 25-question survey mailed to 3056
neonatologists in the United States in 1992 yielded 1131 responses. Seven hundred
seventy-five (775 of 1131, 69%) reported they believed that the lower limit of
viability was 23 to 24 weeks' gestation. These respondents were asked if they
were willing to recommend or provide a series of medical interventions for
infants born at 23 and 24 weeks' gestation. RESULTS: Most respondents would
provide ventilation (82% and 95%) and surfactant (62% and 78%) for infants born
at 23 and 24 weeks' gestation, respectively. The respondent's prediction of <100%
mortality, infant factors, and parental wishes were significant predictors of
willingness to resuscitate infants born at 23 weeks' gestation. CONCLUSION: There
is considerable variation among neonatologists in their willingness to recommend
or provide medical interventions for infants born at 23 to 24 weeks' gestation.
PMID- 9766410
TI - Randomized trial of magnesium administration to prevent hypocalcemia in infants
of diabetic mothers.
AB - OBJECTIVE: Hypocalcemia is common in infants of diabetic mothers (IDMs) and may
be caused by secondary hypoparathyroidism related to hypomagnesemia. This study
was designed to test the hypothesis that prophylactic magnesium sulfate (MgSO4)
administration at birth in IDMs with low cord magnesium concentrations will
prevent neonatal hypocalcemia. STUDY DESIGN: In this randomized trial conducted
in IDMs with a cord magnesium concentration of <0.74 mM (1.8 mg/dl), 26 subjects
received 6 mg/kg elemental magnesium and 23 subjects received no treatment. Serum
concentrations of total and ionized calcium, phosphorus, and magnesium were
recorded at birth, by measuring the concentrations within the umbilical cord, and
at 24 and 72 hours of age. RESULTS: The incidence of hypocalcemia at 72 hours was
0% (0 of 23) in the magnesium-treated group and 12.5% (2 of 16) in the group with
no treatment (p = 0.16). There was no difference in mean serum calcium
concentration at 72 hours between infants in the treated group and the group with
no treatment (2.28 +/- 0.04 vs 2.22 +/- 0.05 mM; p = 0.39). The drop in serum
calcium concentration from birth to 72 hours of age was less for the treated
group (0.30 +/- 0.05 mM [1.23 +/- 0.18 mg/dl]) than the group with no treatment
(0.45 +/- 0.05 mM [1.81 +/- 0.21 mg/dl]; p = 0.04). CONCLUSION: Administration of
intramuscular MgSO4 to IDMs with cord magnesium <0.74 mM (1.8 mg/dl) does not
reduce the incidence of hypocalcemia in infants of well-controlled diabetic
mothers.
PMID- 9766411
TI - Dose-dependent evaluation of the effects of nebulized furosemide on pulmonary
function in ventilated preterm infants.
AB - OBJECTIVE: We have previously shown that a single dose of nebulized furosemide
improves tidal volume and pulmonary compliance for up to a 2-hour study period.
This study is undertaken in order to find out (a) whether increasing the dose of
nebulized furosemide from 1 to 2 mg/kg of body weight will further improve the
pulmonary mechanics in premature infants with evolving chronic lung disease and
(b) whether the effects of a single dose of nebulized furosemide last beyond 2
hours. STUDY DESIGN: The effect of nebulized furosemide on pulmonary mechanics
was studied at a mean postnatal age of 24 days (range 14 to 50 days) in 13
premature infants, 24 to 28 weeks' gestational age, who had been dependent on
mechanical ventilation since birth. Furosemide was administered by nebulization
at doses of 1 and 2 mg/kg of body weight, in random order, on two separate days
24 hours apart. Pulmonary function studies were performed before and 2, 4, and 6
hours after the nebulization. Urine was collected for 6 hours immediately before
and for 6 hours after the nebulization. RESULTS: Furosemide by nebulization at 1
and 2 mg/kg of body weight resulted in significant improvement in tidal volume
and compliance. There was no difference in the magnitude of response between the
two doses. Neither 1 nor 2 mg/kg of body weight of nebulized furosemide had any
effect on airway resistance. The improvement was maximum for up to 4 hours and
lasted for up to 6 hours after the nebulization and was not associated with
diuresis or increased excretion of urinary electrolytes. CONCLUSION: A single
dose of nebulized furosemide improves pulmonary function for up to 6 hours after
its administration. Increasing the dose from 1 to 2 mg/kg of body weight results
in no further improvement in the pulmonary function. The pulmonary effects of
nebulized furosemide are independent of its diuretic action.
PMID- 9766412
TI - Peak noise distribution in the neonatal intensive care nursery.
AB - OBJECTIVE: To measure short duration sounds (L(PEAK)) in the neonatal intensive
care unit and describe their intensity, incidence, and periodicity in
relationship to activities within the unit. STUDY DESIGN: We measured 1-minute
L(PEAK) at four locations within the intensive care unit, accumulating 48 hours
of data for each weekday. RESULTS: Thirty-one percent of the L(PEAK) exceeded 90
dB. For further analysis, the data were transformed to the proportion exceeding
90 dB. These values varied significantly with day, week, location, and time of
day. During physician rounds, there was a 16% relative increase in L(PEAK).
CONCLUSION: These data demonstrate the intensity, incidence, and periodicity of
short duration sounds in the intensive care nursery. Short duration sounds are
known to affect the infant's physiological and behavioral states and should be
addressed in future recommendations for sound control and reduction strategies.
PMID- 9766413
TI - Very low birth weight infants and their families during the first year of life:
comparisons of medical outcomes based on after care services.
AB - OBJECTIVE: To evaluate factors contributing to optimal medical outcomes during
the first year following discharge of very low birth weight infants from tertiary
neonatal intensive care units. STUDY DESIGN: This was a prospective investigation
of the health and development of 81 very low birth weight infants following
discharge from two tertiary neonatal intensive care units in Los Angeles. Infants
were assigned to four groups receiving a variety of after care services in their
homes. Analyses of variance were computed to examine differences between groups
for a variety of outcomes. RESULTS: No statistically significant differences were
seen between after care groups on use of hospital emergency rooms (ER)
rehospitalization rates, or child abuse and neglect. Highest overall rates of
optimal outcomes were seen in the group receiving the highest intensity of after
care services. Those groups receiving long-term home visiting services had
significantly higher rates of up-to-date immunizations. CONCLUSION: There was no
significant impact on infant mortality and morbidity of early discharge,
regardless of the system of after care used. However, those infants who received
the highest level of after care services had the most optimal health outcomes and
were most likely to be receiving well-baby care. It is likely that the
comprehensive, clinic-based system of health care available to all study infants
was a significant factor in low rates of morbidity.
PMID- 9766415
TI - The value of standard electroencephalograms in the evaluation of the newborn with
recurrent apneas.
AB - OBJECTIVE: To determine the usefulness of the standard electroencephalograms in
the evaluation of prematurely born infants admitted to a neonatal intensive care
unit with recurrent apneas and bradycardias. STUDY DESIGN: Retrospective review.
RESULTS: During the study period, 94 infants were evaluated for seizure activity.
Twenty of these were prematurely born infants with recurrent apneas and
bradycardias without clinically recognized seizures. The recordings were entirely
normal in 10 cases, and in 9 showed interictal epileptiform discharges in excess
of or in atypical locations than those expected for the gestational age at the
time of the investigation. One had an abnormal electroencephalogram (EEG) pattern
with episodes of generalized flattening occurring repeatedly throughout the
entire recording. None had electrographic seizures. All infants were free of
sepsis and gastroesophageal reflux and all had normal biochemistry at the time of
the EEG recordings. CONCLUSION: In our study, routine EEG was not found to be
useful in the investigation and management of prematurely born infants with
recurrent apneas not associated with clinically recognized seizure activity.
PMID- 9766416
TI - Use of abnormalities in the Friedman curve as a predictor of operative delivery
in macrosomic babies.
AB - OBJECTIVE: To assess the use of the Friedman labor curve as a predictor of
operative delivery in macrosomic pregnancies. STUDY DESIGN: Medical records of
1141 patients who had delivered babies > or =4000 gm (group 1) were reviewed and
were compared with the results of the next mother who delivered a neonate with
birth weight <4000 gm (group 2). The variables studied were progress of labor as
denoted on the Friedman curve, oxytocin use, and need for operative delivery.
RESULTS: In the 1141 patients with neonatal birth weights > or =4000 gm, there
was a trend toward a longer second stage, arrest disorder, and operative delivery
but this did not reach statistical significance. CONCLUSION: Abnormalities in the
Friedman curve were not useful as a predictor for operative delivery in
pregnancies complicated by fetal macrosomia. There were no statistically
significant differences between the two groups in terms of the variables studied.
PMID- 9766414
TI - Frequency, timing, and diagnoses of antenatal hospitalizations in women with high
risk pregnancies.
AB - OBJECTIVE: To examine the frequency, time of gestation, and reasons for antenatal
hospitalizations in women with medically high-risk pregnancies. STUDY DESIGN:
This secondary analysis reports all antenatal hospitalizations from a clinical
trial testing transitional care to women with high-risk pregnancies. Data were
collected from 1992 to 1996. Pregnant women with pregestational (n = 16) or
gestational diabetes (n = 21), hypertension (n = 29), and diagnosed (n = 47) or
at high risk for preterm labor (n = 37) were included. Diagnoses for each
hospitalization and lengths of stay were collected from chart review and
validated by attending physicians. Gestation was determined via ultrasonography.
The sample (N = 150) consisted of predominantly African-American women, never
married, between the ages of 15 and 40 with Medicaid insurance. RESULTS: Eighty
three percent (n = 125) of the women had one or more antenatal hospitalization
with a mean length of stay of 123 hours. All women with diabetes were
hospitalized at least once. Women with pregestational diabetes had the greatest
number of hospitalizations whereas those with gestational diabetes had the least.
Major reasons for hospitalizations were preterm labor, glucose control, premature
cervical dilation, and preeclampsia. CONCLUSION: Some hospitalizations could
potentially be avoided or reduced through expanded patient education, improved
screening, and more aggressive monitoring for early signs and symptoms of
impending complications.
PMID- 9766417
TI - Examining the "cost" of substance abuse in pregnancy: patient outcomes and
resource utilization.
AB - OBJECTIVE: This study investigated the clinical and financial impact of self
reported maternal drug history and documented intrauterine substance exposure on
maternal-neonatal morbidity and hospital costs. STUDY DESIGN: This two-part, case
controlled, retrospective study used matching control groups. RESULTS: Among
women reporting a history of substance abuse during or prior to the index
pregnancy, (a) maternal hospital costs were significantly higher and more
variable; (b) birth weight, length, and gestational age were lower; (c) no
significant differences were noted in the number of maternal risk factors or
neonatal complications and hospital costs. In comparison of neonates with
positive toxicology screens and a matched control group, there were no
differences in neonatal outcomes or costs, but the number of complicating
maternal risk factors and maternal hospital costs were significantly different.
CONCLUSION: Knowledge of maternal substance abuse history may be useful in
planning for maternal-neonatal care needs and reimbursement for hospital care for
this at-risk patient population.
PMID- 9766419
TI - Prenatal diagnosis and clinical features of an individual with tetrasomy 18p and
trisomy 18q mosaicism.
AB - Prenatal diagnosis and clinical follow up of a patient with mosaicism for
anomalies of chromosome 18 are reported. The fetus appeared on ultrasound to have
multiple anomalies, including clubbed feet, abnormal hand positioning, edema of
the scalp, cleft palate, and polyhydramnios. The karyotype on amniocytes was
47,XY,+i(18p). Postnatally, the peripheral blood karyotype was 46,XY,+i(18q),
whereas the skin fibroblast karyotype was 47,XY,+i(18p). The infant had many
features consistent with those previously described in cases of tetrasomy 18p and
some that were consistent with trisomy 18q.
PMID- 9766418
TI - Congenital and perinatal tuberculosis: discussion of difficult issues in
diagnosis and management.
AB - Tuberculosis (TB) has become more prevalent in women of childbearing age and, as
well, more frequent in their children. This has occurred for a number of reasons,
including: (1) women and children who have immigrated to this country from areas
where TB is endemic, such as Mexico and Southeast Asia; (2) the development of
multidrug-resistant organisms; (3) the increase seen in patients who live in
congregate areas who are at higher risk for acquisition of TB; (4) more difficult
access to adequate medical care; and (5) increases in adults and children who
have become infected with human immunodeficiency virus. The focus of this review
is on congenital and perinatally acquired TB including discussion of
epidemiology, the stages of TB, the effects of TB infection and disease during
pregnancy on the fetus and mother, congenital and perinatal TB, the potential
role of the use of BCG vaccine in infants, and the emergence of multidrug
resistant TB on therapy of the pregnant mother and her fetus and the mother and
her infant after delivery.
PMID- 9766420
TI - "Pseudo" twin-to-twin transfusion syndrome and fetal outcome.
AB - OBJECTIVE: To assess the fetal outcome, in a tertiary center, in pregnancies with
suspected twin-to-twin transfusion syndrome (TTTS) not confirmed using
ultrasonographic examination, diagnosis of pathology, or both. STUDY DESIGN:
Forty-four pregnancies with suspected TTTS were followed longitudinally using
ultrasonographic examination until delivery. The minimal criteria for the
diagnosis of TTTS were: (1) suspicion of monochorionicity gleaned from ultrasound
examination (to be confirmed at birth); (2) presence of polyhydramnios in one
gestational sac (either assessed subjectively--or, finding that the largest
vertical pocket of amniotic fluid was >8 cm in diameter before 20 weeks'
gestation and >10 cm in diameter thereafter); and (3) presence of oligohydramnios
in the other gestational sac (finding either that there was a "stuck" twin
complication or that the largest vertical pocket of amniotic fluid was <1 cm in
diameter). When one of the above criteria was not present, the pregnancy was
defined as "pseudo" TTTS. Fetal outcome in "pseudo" TTTS was analyzed according
to the relative size of the neonate (large or small) and whether the cord
insertion was normal or velamentous. RESULTS: There were 18 cases of "pseudo"
TTTS. No treatment in utero was necessary in any of the 18 pregnancies. The mean
gestational age was 21.9 +/- 3.7 (1 SD) weeks at diagnosis and 33.0 +/- 3.0 weeks
at delivery. The average weight discrepancy between the twins at birth was 34.3
+/- 14.8%. There were three fetal demises of the small twin and one neonatal
demise of the large twin (p > 0.05). Large twins developed respiratory distress
syndrome (RDS) more often than small twins (p < 0.05). Five percent of the large
twins and 50% of the small twins had a velamentous insertion of the cord (p <
0.05). CONCLUSION: In pregnancies complicated by "pseudo" TTTS our data indicate
that: (1) small twins have abnormal cord insertion more frequently than large
twins, (2) large twins develop RDS more frequently than small twins. Our data
suggest that the perinatal mortality in these pregnancies appears to be lower
than that reported for the classical TTTS.
PMID- 9766421
TI - Fetal heart rate monitoring casebook. Benign recurrent late decelerations.
PMID- 9766422
TI - Special imaging casebook. Neonatal malignant rhabdoid tumor of the kidney.
PMID- 9766423
TI - Neonatal transport: a protocol for ambulance transfer to a neonatal intensive
care unit.
PMID- 9766424
TI - Endotracheal tolazoline administration in neonates with persistent pulmonary
hypertension.
PMID- 9766425
TI - Introduction to histological and histochemical aspects of wound healing.
PMID- 9766426
TI - Analysis of extracellular matrix synthesis during wound healing of retinal
pigment epithelial cells.
AB - To investigate changes in retinal pigment epithelial (RPE) cells during wound
healing, we evaluated the deposition of newly synthesized extracellular matrix
(ECM) over time during wound healing in rat RPE cultures. We also estimated the
effect of growth factors on the healing rate and ECM synthesis. After preparing
rat RPE cell sheet cultures, we made round 1-mm defects in the cultures.
Fibronectin, laminin, and collagen IV synthesis were evaluated with
immunocytochemistry every 12 hours after wounding. S-phase cell distribution was
analyzed every 12 hours by 5-bromodeoxyuridine uptake. We added either platelet
derived growth factor (PDGF), epidermal growth factor (EGF), or transforming
growth factor- beta2 (TGF-beta2) to cultures at concentrations of 1, 10, and 100
ng/mL and immunocytochemically analyzed the effects on ECM and estimated the rate
of wound closure. Although approximately 50% closure was achieved 24 hours after
wounding, fibronectin deposits first appeared at that time. Laminin and collagen
IV were first detected at 36 hours and fibronectin staining had extended toward
the wound center. S-phase cells were distributed in concentric rings that moved
centripetally over time and corresponded to the leading edge of the area stained
with anti-ECM antibodies. TGF-beta2 enhanced ECM deposition, but EGF and PDGF did
not. TGF-beta2 decreased the healing rate in a dose-dependent manner, whereas
PDGF promoted wound closure. EGF enhanced closure at the highest concentration
only. In summary, wound healing in RPE may be initiated when cells at the wound
edge slide or migrate toward the wound center, which is followed by cell
proliferation and then ECM synthesis. ECM components may be produced in a
specific sequence during healing. TGF-beta2 may promote RPE cell differentiation,
and PDGF may enhance proliferation during wound healing of the RPE.
PMID- 9766427
TI - Understanding and controlling the scarring response: the contribution of
histology and microscopy.
AB - In response to injury, the body usually initiates a full and swift wound healing
response resulting in reconstructed, repaired tissue. In certain instances, due
to a variety of factors, this may not happen, an example being chronic
granulating venous leg ulcers. At the other extreme, the wound may heal
excessively, producing disabling hypertrophic scarring such as can occur
following large, deep burn injuries. Our group is interested in the surgical
treatment of the eye disease glaucoma. As will be explained, the successful
surgical treatment of this disease depends on a reduced scarring response at the
end of wound healing. The purpose of this article is to give an overview of our
microscopic and histological experimental work which has furthered our
understanding of tissue repair, particularly the scarring response and its
potential modification for successful glaucoma surgery.
PMID- 9766428
TI - Ultrastructural and cytochemical study of neurones in the rat dorsal motor
nucleus of the vagus after axon crush.
AB - The cell populations in the dorsal motor nucleus of the vagus (DMNV) of the rat
were studied by light microscopy and transmission electron microscopy, including
retrograde labeling with horseradish peroxidase and histochemical demonstration
of the distribution of the activity of the enzymes acetylcholinesterase (AcChE)
and butyrylcholinesterase (BuChE). Two types of neurones were observed: 1) Larger
Type A cells, which stain for both AcChE and BuChE and which project into the
vagus nerve trunk, and 2) smaller Type B cells, which stain lightly for AcChE but
not for BuChE and which do not project into the vagus nerve. Standardised vagal
crush at the mid-cervical level causes loss of cholinesterase activity in Type A
neurones within a few days but has no effect on Type B neurones. Changes in
nuclear morphology of Type A neurones are pronounced at 10 weeks postinjury,
indicating that degeneration is irreversible even by this stage. The number of
Type A cells projecting to the vagus nerve reduces as a function of time,
presumably as these cells die. Only a small number of Type A neurones persist at
2 years postinjury.
PMID- 9766429
TI - Modeling of wound healing processes in human skin using tissue culture.
AB - To facilitate the investigation of the complex process that leads to healing of a
human skin wound we developed standardized and repeatable in vitro models for
both incisional and burn wounds. Wounds with a standardized area and depth were
created in normal human skin biopsies which were then incubated in vitro. It was
shown, by cultivation, that both dermal and epidermal cells maintained their
viability during a 14-day in vitro incubation if exposed to at least 2% fetal
calf serum. By incubating in 10% serum, the skin samples were stimulated to
completely re-epithelialize the wounded area. Because a large number of
standardized wounds can be obtained from each donor, the re-epithelialization
process can be studied histologically and immunohistochemically at several
adjacent time points. The ability to keep the cells in the wound area viable
without stimulating healing by incubating the wounds in suboptimal serum
concentrations implies a way of studying the stimulatory effects of different
agents, such as growth factors, on the wound healing process. There were some
marked discrepancies in the healing process between the incisional and burn
wounds which resemble the in vivo situation, indicating that the in vitro models
could be used to more closely study differences between healing in different
types of wounds. Our findings suggest that in vitro tissue culture can be of
great value in attempting to better understand the complex process of wound
healing in human skin.
PMID- 9766430
TI - A microscopical study of wound repair in the human placenta.
AB - In order to fulfill its many functions as the selective interface between
maternal and fetal circulations it is imperative that the human placenta remains
intact and in good operational order. That damage of some sort occurs during its
short but extremely active life seems inevitable given the dynamic environment in
which the placenta exists, and evidence has accumulated that disruption is indeed
a regular event. The implications of such damage, one could speculate, may impact
on functions such as transport and hormone secretion as well as mutual protection
against attack by maternal and fetal immune systems. Consequently, it would seem
a theoretical necessity for discontinuities in the placenta surface to be
repaired as soon as possible. We have used a combination of ex vivo observation,
in vitro modelling, immunohistochemistry and correlative microscopy to provide
evidence for a wound response in the placenta and to begin dissecting the detail
of how this may operate. Evidence for small lesions caused by fusion and
subsequent tearing of the syncytiotrophoblast in vivo, as well as plugging of
such wounds by underlying cells is shown. We also identify a putative role for
migratory cytotrophoblasts in the healing of larger scale injuries and
demonstrate that certain molecules, common to wound repair in other tissues,
appear to be involved in placenta repair also. Taken together these results
clearly show that the human placenta is capable of a degree of self-maintenance
by activating what appears to be an endogenous wound healing mechanism.
PMID- 9766431
TI - Cytochemical demonstration of sites of hydrogen peroxide generation and increased
vascular permeability in isolated pig hearts after ischaemia and reperfusion.
AB - Isolated pig hearts, subsequently perfused with pig or human blood, were prepared
for the cytochemical demonstration of sites of hydrogen peroxide generation and
increased vascular permeability. Oxidant stress was associated with
ultrastructural changes commonly seen following myocardial reperfusion. In
addition, the precipitation of cerium perhydroxide following perfusion with
physiological saline containing cerium chloride suggested the vascular
endothelium and leukocytes as sources of oxidants. This was associated with rapid
penetration of horseradish peroxidase through the intercellular clefts of the
vascular endothelium into the interstitial space, suggesting increased vascular
leakiness at these sites. The rapid penetration of horseradish peroxidase was
observed at all monitored periods of reperfusion with pig or human blood. This
indicates that the increased permeability occurred during the ischaemic period
and continued during reperfusion. Morphological damage was greatest in pig hearts
reperfused with whole human blood and this was attenuated if the blood was
preabsorbed to remove antibodies prior to reperfusion. We conclude that oxidant
stress was initiated during ischaemia and continued during reperfusion in this
model.
PMID- 9766432
TI - Relaxed cell-cycle arrests and propagation of unrepaired chromosomal damage in
cancer cell lines with wild-type p53.
AB - The role of the p53 protein in mediating G1 and G2 cell-cycle arrests after
genotoxic insult has been clearly and reproducibly established in primary diploid
fibroblasts, but data obtained from p53 wild-type (wt) cancer cell lines are
inconsistent. Furthermore, a large proportion of human tumors have p53 wt
genotypes but present genetic aberrations that may result from defective cell
cycle checkpoints. We therefore investigated the integrity of G1/S and G2/M cell
cycle arrests in p53 wt cancer cell lines. In the study presented here, we showed
that in most cancer cells tested, G1 arrest was relaxed or absent in comparison
with arrest in normal diploid fibroblasts, despite seemingly normal p53 and p21
responses. Two cell lines (MCF7 and HCT116) were synchronized in G0/G1 by leucine
starvation and subjected to genotoxic stress to determine more precisely the
relative proportion of cells arresting in G1 and G2. Whereas the MCF7 cells
showed consistent G1 arrest, the HCT116 cells showed none at all. Furthermore,
cell-cycle arrests in G1 and G2 in response to gamma irradiation and bleomycin
treatment were transient, as the cells resumed cycling after 48-72 h. The cells
resuming proliferation suffered massive apoptosis, but a proportion of the cells
were rescued and showed normal doubling times. These cells retained a p53 wt
genotype but presented gross chromosomal aberrations in 15-20% of the analyzed
metaphases. The aberrations were not clonal. These data show that p53 wt cancer
cells have relaxed cell-cycle controls after genotoxic insult and tolerate
unrepaired chromosomal damage, despite normal p53 function.
PMID- 9766433
TI - Androgen regulation of the human pseudoautosomal gene MIC2, a potential marker
for prostate cancer.
AB - Using the differential display-polymerase chain reaction technique to identify
androgen-responsive genes in the human prostatic tumor cell line LNCaP, we cloned
an expression tag homologous to the human pseudoautosomal gene MIC2. The role of
MIC2 in the prostate had not previously been studied. We used a series of cell
lines derived from LNCaP that varied in their degree of differentiation and
metastatic potential to assess the relationship between MIC2 expression and
androgen responsiveness in prostate cancer. The expression of MIC2 mRNA and its
product E2 was upregulated by androgen in a dose- and time-dependent manner in
the parental LNCaP line and correlated with the expression of prostate-specific
antigen. In the LNCaP sublines and an androgen-repressed invasive human prostate
cancer cell line (ARCaP), MIC2 gene expression was not regulated by androgen and
was associated with poorer differentiation, decreased androgen sensitivity, and
higher metastatic potential. Immunohistochemical analyses indicated that E2 was
expressed in tissues from patients with primary prostate cancer (16 of 20), in
fetal prostatic tissues (low levels in all 10 fetal tissues assessed), and
sporadically in benign prostatic hyperplasia tissues (one of four). The normal
prostate tissues did not show positive E2 staining, with the exception of one
central-zone section from one of the eight normal prostate samples assessed.
These findings suggest that deregulation of expression of the human
pseudoautosomal gene MIC2 occurred in the prostate.
PMID- 9766434
TI - Malignant transformation of simian virus 40-immortalized human milk epithelial
cells by chemical carcinogenesis accompanied by loss of heterozygosity on
chromosome 1 but not microsatellite instability.
AB - Simian virus 40-immortalized human milk epithelial cells (HuMI) are anchorage
dependent and non-tumorigenic but can spontaneously progress to anchorage
independent and tumorigenic cells. To see whether HuMI cells can be transformed
into anchorage-independent cells by chemical carcinogens, we treated them with 3
methylcholanthrene (MCA, 10 microg/mL). After 7-8 wk of culture, none of the
treated cells grew in soft agar. However, when HuMI cells treated with MCA were
cultured with 12-O-tetradecanoylphorbol-13-acetate (TPA, 10 ng/mL), they grew in
soft agar; cells treated with TPA alone did not. TPA at this dose was cytotoxic
to HuMI cells but not to their tumorigenic subline HuMI-TTu2. The response of the
anchorage-independent HuMI-T cells was intermediate. These results indicate that
HuMI cells can be transformed by treatment with MCA plus TPA, possibly because
TPA selects those cells that are progressing toward malignancy. All five clones
from MCA plus TPA-induced transformed cells formed malignant carcinomas in nude
mice. When microsatellite changes at 17 loci in HuMI, HuMI-T, HuMI-TTu2, and five
MCA plus TPA-transformed cells were examined, none of these cell lines showed
instability at any locus, and no change in microsatellite length was found.
However, all five MCA plus TPA-transformed cell lines showed loss of
heterozigosity at 1q21-23 and 1q42 loci. This region of chromosome 1 is known to
contain at least one antiproliferative gene, and our results suggest that
inactivation of such a gene may be essential for full transformation of HuMI
cells by chemical carcinogens.
PMID- 9766435
TI - Induction of growth inhibition of 293 cells by downregulation of the cyclin E and
cyclin-dependent kinase 4 proteins due to overexpression of TIS21.
AB - We earlier reported that TIS21 mRNA expression was markedly decreased in A549 and
NCIH69 human lung cancer cells and in thymic carcinoma tissues obtained from
transgenic mice containing simian virus 40 large T antigen (J Cancer Res Clin
Oncol 121:279-284, 1995). To determine how TIS21 inhibits growth, we made 293
cells that constitutively expressed TIS21 protein. The constitutive TIS21
expresser lines C9 and C11 grew to a lower saturation density than did those in
the vector-transfected clones (V7 and V10) and antisense-transfected clones (AS1
and AS4), and the size of the C9 and C11 cells increased significantly after
transfection with TIS21 cDNA. The serum-stimulated cell cycle was analyzed by
fluorescence-activated cell sorting after double thymidine treatment; V10
progressed normally through the cell division cycle, but C9 and C11 cells
accumulated continuously in G1 phase until 36 h after treatment. On the other
hand, the progression of cells that had already entered to S or G2/M phase was
not inhibited. When cell-cycle regulatory proteins were measured, C9 and C11
cells showed significantly reduced synthesis of cyclin E and cyclin-dependent
kinase (cdk) 4 as well as a decrease in cyclin E-associated cdk activity. These
observations led us to conclude that TIS21 overexpression in G1 phase decreased
the amounts of cyclin E and cdk4, thereby decreasing the activity of cdks at the
G1-S transition.
PMID- 9766437
TI - Skin tumorigenesis and Ki-ras and Ha-ras mutations in tumors from adult mice
exposed in utero to 3'-azido-2',3'-dideoxythymidine.
AB - This study was designed to evaluate the potential initiating effects of
transplacental 3'-azido-2',3'-dideoxythymine (AZT) and the role of ras mutational
activation in skin tumors induced in a two-stage mouse skin model. In addition,
mouse liver and lung tumors from a transplacental AZT tumorigenicity study
reported elsewhere (Olivero et al., J Natl Cancer Inst 89:1602-1608, 1997) were
examined for evidence of ras activation. For both tumor studies, pregnant CD-1
mice were given either vehicle or 25 mg of AZT daily on days 12-18 of gestation.
In the 1997 study, the offspring were given no further exposure and were killed
at 1 yr of age. For the skin tumor study, all mice received twice-weekly topical
12-O-tetradecanoyl-phorbol-13-acetate (TPA) treatment from weeks 5-35; half of
the mice had been exposed to AZT in utero. At weeks 16-18, 30, 31, and 34-41, the
skin tumor incidences in mice given AZT and TPA were significantly higher than in
mice given TPA alone (P < or = 0.05). At week 41, the average numbers of tumors
per mouse were 1.44+/-0.36 (mean +/- standard error of the mean) and 0.57+/-0.13
for mice given AZT plus TPA and TPA alone, respectively (P = 0.006). Mutagenesis
in ras exons I and II was determined by polymerase chain reaction (PCR) and dye
terminator cycling sequencing of PCR products. Ha-ras exon I codons 12 and 13
were mutated in 11 of 19 tumors (58%) from mice given AZT and TPA and in one of
15 tumors (7%) from mice given TPA alone (P= 0.004). The only mutation in Ha-ras
codon 12 (four in four tumors examined) was a G-->A transition in the second
base, and the major mutation in codon 13 (six in seven tumors examined) was a G-
>T transversion in the second base. In skin tumors, AZT exposure did not increase
the number of Ha-ras codon 61 mutations, and no Ki-ras mutations were observed.
Analysis of ras mutations in liver and lung tumors from mice exposed to AZT in
utero (Olivero et al., J Natl Cancer Inst 89:16021608, 1997) with no TPA
promotion showed no significant AZT-related increases.
PMID- 9766436
TI - Localization of prostaglandin H synthase isoenzymes in murine epidermal tumors:
suppression of skin tumor promotion by inhibition of prostaglandin H synthase-2.
AB - The growth factor- and phorbol ester-inducible prostaglandin H synthase (PGHS)-2
has been found to be constitutively overexpressed in epidermal tumors generated
by the initiation-promotion protocol in murine skin, whereas the expression of
PGHS-1 does not change under these conditions. In this paper we report the intra
tumor distribution of the aberrantly expressed PGHS-2 and the cancer
chemopreventive activity of a specific PGHS-2 inhibitor. By immunohistochemical
methods using isoenzyme-specific antibodies, we found that the PGHS-1 protein was
expressed in keratinocytes and Langerhans cells dispersed throughout the
epithelial part of papillomas and squamous cell carcinomas and in inflammatory
infiltrates occasionally seen in these tumors. A uniform pattern of PGHS-2
expression was observed in the basal keratinocytes of papillomas and in the
follicular keratinocytes of carcinomas. In addition, Langerhans cells as well as
tumor-associated inflammatory infiltrates exhibited PGHS-2-specific
immunoreactivity. PGHS-2-catalyzed prostaglandin synthesis stimulated by the
phorbol ester 12-O-tetradecanoylphorbol-13 acetate (TPA) in mouse epidermis in
vivo was dose-dependently suppressed by topical administration of SC-58125, a
specific PGHS-2 inhibitor. TPA-induced edema formation, epidermal DNA synthesis,
and mitotic activity were not impaired by SC-58125 applied at a dose that
inhibited TPA-induced prostaglandin E2 synthesis. However, the repetitive
epicutaneous administration of SC-58125 substantially and significantly
suppressed papilloma development. Malignant progression of papillomas was
slightly retarded by the drug. These results indicate that aberrant expression of
PGHS-2 in epidermal tumors may be a relevant target for prevention of epidermal
cancer development in experimental animals and that the PGHS-2-specific inhibitor
SC-58125, which is a potent inhibitor of tumor promotion in mouse skin, may be
important for cancer chemoprevention in humans as well.
PMID- 9766438
TI - Is excessive spontaneous intramedullary apoptosis unique to myelodysplasia?
PMID- 9766439
TI - While waiting for Christopher Columbus to discover alternative route(s) of bone
marrow regulation, keep faith the body is a global system.
PMID- 9766440
TI - Regulation of erythropoiesis by bone marrow reninangiotensin system: facts and
speculations.
PMID- 9766441
TI - CD34- stem cells as the earliest precursors of hematopoietic progeny.
PMID- 9766442
TI - Serum of healthy donors receiving granulocyte colony-stimulating factor induces T
cell unresponsiveness.
AB - The effects of serum from healthy donors receiving recombinant human granulocyte
colony-stimulating factor (rhG-CSF) (G-serum) on blast transformation, expression
of activation-related antigens, secretion of interleukin (IL)-2, and
proliferation were evaluated in allogeneic lymphocytes stimulated with
phytohemagglutinin. Escalating concentrations of G-serum induced 27%, 47%, and
70% suppression of lymphocyte proliferation; interestingly, CD4+ and CD8+ cells
underwent blast transformation and up regulated early (CD69) and late (CD25, HLA
DR, and CD71) activation-related antigens. Negligible fractions of apoptotic
cells were found after mitogenic challenge, suggesting that the strongly
diminished proliferation was not attributable to extensive activation-induced
programmed cell death of responding T cells. The levels of IL-2 in cultures
containing G-serum were comparable to those in cultures performed without G
serum; however, high concentrations of exogenous IL-2 restored lymphocyte
mitogenesis regardless of G-serum concentration. These findings--cell
enlargement, upregulation of activation-related antigens, inability to
proliferate after mitogenic stimulus, and restoration of cell division by
exogenous IL-2--resembled those associated with "partial activation" of
lymphocytes, a fundamental control mechanism of tolerance induction in T cell
clones. Soluble immunoregulatory mediators infused with allogeneic hematopoietic
progenitor products collected after rhG-CSF administration could induce T cell
unresponsiveness in vivo, thus preventing clonal expansion and amplification of
immune responses, and could account for the unexpectedly reduced incidence and
severity of graft vs. host disease compared with allogeneic marrow infusion.
PMID- 9766443
TI - CD34++ CD38- and CD34+ CD38+ human hematopoietic progenitors from fetal liver,
cord blood, and adult bone marrow respond differently to hematopoietic cytokines
depending on the ontogenic source.
AB - CD34++ CD38- and CD34+ CD38+ hematopoietic progenitor cells (HPCs) from human
fetal liver (FL), cord blood (CB), and adult bone marrow (ABM) were isolated and
investigated for their growth characteristics, cytokine requirements and response
to two modulators of early hematopoiesis, interferon (IFN)-gamma and macrophage
inflammatory protein (MIP)-1alpha. We observed first that a significantly lower
percentage of CD34++ cells were CD38- in ABM than in FL and CB. Second, the
functional differences between CD34++ CD38- and CD34+ CD38+ cells were less
pronounced in FL and CB than in their ABM counterparts. Third, an inverse
correlation was found between growth factor response and the ontogenic age of
HPCs, and a direct correlation was noted between cytokine requirements and the
ontogenic age of HPCs. Fourth, spontaneous colony formation in a classic
semisolid culture system was reproducibly obtained only in the ontogenically
earliest cells, that is, in FL but not in CB and ABM, in which no such
spontaneous colony formation was observed. Fifth, the modulatory effects of IFN
gamma and MIP-1alpha were qualitatively different depending on the ontogenic age
of the progenitor source: whereas IFN-gamma was only a selective inhibitor of
primitive CD34++ CD38- ABM progenitor cells, it inhibited both CD34++ CD38- and
CD34+ CD38+ FL and CB cells to the same extent. In contrast to the effects of MIP
1alpha on ABM, we could not find any consistently stimulatory or inhibitory
effects on FL and CB progenitors. In conclusion, important functional and
biologic differences exist between FL, CB, and ABM progenitor cells, and these
differences could have major implications for the use of these cell populations
in preparative protocols of ex vivo expansion, transplantation strategies, or
gene transfer experiments.
PMID- 9766444
TI - p53-dependent and -independent differentiation of leukemic U-937 cells:
relationship to cell cycle control.
AB - Observations based on overexpression of the suppressor gene p53 or interference
with endogenous p53 support a role for p53 in mediating not only growth
inhibition and apoptosis but also differentiation. The aim of this study was to
characterize the mechanisms of p53-dependent differentiation in the monoblastic
leukemia cell line U-937. These cells were transfected with a mutant of the p53
gene expressing wild-type p53 at a permissive temperature. The results showed
that wild-type p53 and interferon (IFN)-gamma were able to work synergistically
to promote differentiation. This cooperative response was not associated with
early G1 arrest of the cell cycle, indicating that p53 can mediate
differentiation by mechanisms other than those used for mediating G1 arrest. The
differentiation response to transfected p53 with or without INF-gamma was
inhibited by cyclic adenosine monophosphate (cAMP)-inducing agents (dibutyryl
cyclic adenosine 3':5'-monophosphate, forskolin, and 3-isobutyl-1-methylxanthine)
in a dose-dependent manner. In contrast, the differentiation response of p53
negative U-937 cells to 1,25-dihydroxychole-calciferol or all-trans retinoic acid
was enhanced by cAMP-inducing agents at optimal concentrations and inhibited at
higher concentrations. In addition, 1,25-dihydroxycholecalciferol-mediated
differentiation could be achieved in cells arrested in G1 by concomitant
incubation with cAMP-inducing agents, indicating that differentiation can occur
in the absence of proliferation. In conclusion, the results of this study
indicate that p53-dependent and -independent differentiation can occur
independently of cell cycle regulation.
PMID- 9766446
TI - Immunophenotypic characterization of stromal cells in aspirated human bone marrow
samples.
AB - The presence of stromal cells was investigated in aspirated bone marrow prepared
by the same method as that used for the initiation of human long-term bone marrow
culture (hLTBMC). In previous studies, we performed immunocytochemical staining
of cytocentrifuge cell preparations using a panel of antibodies with which we
characterized stromal cell populations in hLTBMC. This approach allowed
morphological as well as immunophenotypic assessment of cells of interest.
Morphologically distinctive cell populations expressing vascular cell adhesion
molecule-1 and low-affinity nerve growth factor receptor (NGFR) were observed to
be present, but no cells expressing alpha-smooth muscle actin were found. Few
macrophages were present, consistent with the origin of hLTBMC stroma-adherent
macrophages from monocytes and their precursor cells rather than from mature
macrophages among the culture-initiating cells. In the absence of double
immunostaining, it was not possible to deduce whether CD34+ cells, which were
present in varying numbers in the cytocentrifuge preparations, included stromal
as well as primitive hematopoietic cells. In addition to single cells,
multicellular tissue fragments containing a variety of stromal cell types were
detected in many samples. Their presence raises the possibility that at least
some components of hLTBMC stroma may arise by explant growth from complex tissue
fragments containing vascular and fibroblastic elements. Overall, our results
indicate that demonstration of a variety of stroma-associated antigens, in
particular NGFR, provides a useful new tool for identifying stromal elements in
aspirated bone marrow.
PMID- 9766445
TI - Modulation of iron metabolism in monocytic THP-1 cells and cultured human
monocytes by the acute-phase protein alpha1-antitrypsin.
AB - The reticuloendothelial (RE) system plays an important role in the changes in
iron metabolism associated with the anemia of chronic disease (ACD). We
previously reported that the acute-phase protein alpha1-antitrypsin (alpha1-AT)
reduced growth and proliferation in cells of the erythroid cell system by
interfering with transferrin (Tf)-mediated iron uptake. The regulation of iron
metabolism in cells of the RE system is distinctly different from that in other
cell systems; moreover, monocytes and macrophages play an essential part in the
regulation of the production and clearance of alpha1-AT. In the present study we
examined the effect of alpha1-AT on cells of the monocyte-macrophage lineage.
Alpha1-AT completely inhibited the binding of Tf to its receptor (TfR) on THP-1
human myelomonocytic cells and cultured human monocytes. Results of equilibrium
saturation and kinetic studies indicated that this inhibition was competitive. No
other acute-phase protein demonstrated the same inhibitory potency. Furthermore,
alpha1-AT almost completely prevented internalization of the Tf-TfR complex in a
dose-dependent manner. Interestingly, and in sharp contrast to the results of our
studies with erythroid cells, this inhibition did not reduce the growth and
proliferation of THP-1 cells. Furthermore, alpha1-AT significantly increased the
concentration of intracellular ferritin in THP-1 cells and monocytes, whereas the
number of TfR remained unchanged. Because alpha1-AT showed no enhancing effect on
ferritin transcription and translation, we believe that an as-yet unidentified
posttranslational mechanism may be responsible for this phenomenon. In addition,
our results indicate that the increase in ferritin concentration caused by alpha1
AT is mediated independently of iron supply, as has previously been shown for
several proinflammatory cytokines. These data provide further evidence that
alpha1-AT is a mediator of the alterations in iron metabolism characteristic of
ACD.
PMID- 9766447
TI - Eradication of residual disease by administration of leukemia-specific T cells
after experimental allogeneic bone marrow transplantation.
AB - It is now well established that allogeneic lymphocytes can mediate a potent graft
vs.-leukemia (GVL) reaction when administered to bone marrow transplant (BMT)
recipients. The benefit of allogeneic lymphocyte transfusion is limited because
many patients develop graft-vs.-host disease (GVHD) with prolonged pancytopenia,
which sometimes proves fatal. The object of the present study was to determine
the antileukemic potential and GVHD risk of in vivo-generated tumor-specific
allogeneic T cells given shortly after BMT. BALB/C (H-2d) mice were inoculated
with different cell doses (10(5) and 5 x 10(5)) of the A20 leukemia (BALB/C
origin) 2 days prior to lethal total-body irradiation (TBI) and transplantation
of allogeneic, major histocompatibility complex (MHC)-matched DBA marrow grafts
(H-2d, minor difference to BALB/C). Donors of BM grafts and T cells were
allogeneic, MHC-matched mice (DBA, H-2d, minor difference to BALB/C). Donor-type
T cells were generated from mice immunized with irradiated A20 leukemia cells or
nonmalignant BALB/C splenocytes and restimulated in vitro. Whereas no significant
immunotherapeutic effect was seen in mice with high tumor burden (5 x 10(5)),
allogeneic BMT in mice inoculated with 1 x 10(5) A20 cells resulted in a modest
antileukemic effect. This survival rate remained unchanged when 10(6) T cells
obtained from donors immunized with nonmalignant BALB/C derived cells were given
posttransplantation. In contrast, a single injection of 10(6) T cells from
leukemia-immunized donors led to potent GVL effects without mediating clinically
overt GVHD. Our data provide evidence for the hypothesis that minimal residual
disease can be eradicated without inducing GVHD by administering small amounts of
specific allogeneic cytotoxic T cells after BMT.
PMID- 9766448
TI - Lisinopril, an angiotensin I-converting enzyme inhibitor, prevents entry of
murine hematopoietic stem cells into the cell cycle after irradiation in vivo.
AB - The hemoregulatory peptide N-Acetyl-Ser-Asp-Lys-Pro (AcSDKP) has been shown in
vivo to inhibit the cycling of murine hematopoietic stem cells triggered into S
phase by either cytotoxic drug administration or irradiation. This property,
further confirmed using in vitro models, demonstrates that the peptide has an in
vivo protective effect on the hematopoietic system. AcSDKP has been shown to be a
physiological substrate of angiotensin I-converting enzyme (ACE), which
catabolizes the peptide through a dipeptidasic activity. Thus, oral
administration of ACE inhibitor to humans has led to an increase in the plasma
AcSDKP concentration. In the present paper, we report on the in vivo effect of
lisinopril, an ACE inhibitor, on the proliferative status of murine hematopoietic
stem cells triggered into S-phase by irradiation. Administration of lisinopril
(10 mg/kg) 1 hour after irradiation led to a 90 to 100% inhibition of murine
plasma ACE activity as observed during the first 4 hours postirradiation. This
inhibition was correlated with a 600% increase in the endogenous plasma AcSDKP
level and a total suppression at 24 hours of entry of the hematopoietic stem cell
into the cell cycle. We discuss the possible role of ACE in the regulation of
hematopoietic stem cell proliferation through control of the AcSDKP
concentration.
PMID- 9766449
TI - Macrophage-stimulating protein (MSP) and its receptor, RON, stimulate human
osteoclast activity but not proliferation: effect of MSP distinct from that of
hepatocyte growth factor.
AB - Stem cell-derived tyrosine kinase (STK) is a member of the hepatocyte growth
factor (HGF) receptor family. The ligand for STK, macrophage-stimulating protein
(MSP), is a serum protein activated by members of the coagulation cascade. The
RON gene is a human homolog of the murine STK. In this study we examined the role
of MSP-RON in the signal pathway of human osteoclasts. Using anti-RON antibody,
we detected RON expressed in multinucleated osteoclast-like cells (OCLs) formed
in cultures of human bone marrow cells. To determine bone resorption, we placed
OCLs on thin films of ceramic calcium phosphate formed on quartz plate-coated
slides (Millenium Biologix) and measured pit formation. MSP stimulated pit
formation by OCLs in a dose-dependent manner. MSP (50 ng/mL) caused a fourfold
increase in pit area compared with the control. Furthermore, we examined the
effects of MSP and HGF on OCL formation by purified populations of hematopoietic
progenitors. OCLs were phenotypically identified by their cross-reactivity with
23c6, a monoclonal antibody that preferentially binds to osteoclasts. HGF (50
ng/mL) stimulated the differentiation of progenitors to 23c6-positive OCLs but
did not enhance bone absorption. In contrast, MSP did not affect proliferation of
osteoclast precursors but stimulated bone resorption by OCLs. We conclude that
the MSP signal transduction pathway plays a role in bone resorption that is
distinct from that of HGF.
PMID- 9766450
TI - CD34 expression by embryonic hematopoietic and endothelial cells does not require
c-Myb.
AB - CD34 is a cell-surface glycoprotein expressed in a developmental, stage-specific
manner by bone marrow stem and progenitor cells. In this study we explored a
possible role for c-Myb in CD34 regulation during developmental hematopoiesis.
The results indicate that c-Myb can induce CD34 expression in hematopoietic and
nonhematopoietic cells, and that murine CD34 promoter activity is enhanced in
myeloid cells transgenic for c-Myb. To test whether c-Myb is necessary for CD34
expression during developmental hematopoiesis in vitro, c-Myb-null D3 embryonic
stem (ES) cells were analyzed for their ability to develop CD34+ hematopoietic
cells in vitro. CD34 promoter activity in transient transfections and CD34
upregulation during ES cell differentiation into embryoid bodies was identical in
wild-type and c-Myb-null ES cells, indicating that c-Myb is not required for CD34
expression. CD34 protein is expressed on both hematopoietic and endothelial cells
of the E8.5 blood islands during the development of c-Myb-null embryos, and
expression is nearly identical in wild-type and c-Myb-null embryos. However, in
E12.5 c-Myb-null embryos, the majority of identifiable CD34+ cells in the
developing liver are endothelial rather than hematopoietic, which is consistent
with the absence of colony-forming units in c-Myb-null embryos and developing ES
cells. These data indicate that c-Myb is not required for CD34 expression in
endothelial or primitive hematopoietic cells in the yolk sac, but is necessary
for definitive hematopoiesis.
PMID- 9766451
TI - Inhibition of interleukin-1beta-converting enzyme in human hematopoietic
progenitor cells results in blockade of cytokine-mediated apoptosis and expansion
of their proliferative potential.
AB - Inhibitory and stimulatory cytokines regulate the function and survival of
hematopoietic progenitor cells. Interactions between cytokines and progenitor
cells may result in programmed cell death. Apoptosis of hematopoietic cells
ultimately serves to diminish the size of the stem cell compartment in bone
marrow (BM) failure, and this has frustrated efforts at ex vivo expansion of
hematopoietic stem cells for BM transplantation. We previously demonstrated that
triggering of the Fas-receptor, which is expressed on BM CD34+ cells, mediates
apoptosis of progenitor cells. Although interleukin-1beta-converting enzyme (ICE)
appears to be an important factor in the signaling cascade regulating Fas
mediated apoptosis of lymphoid cells, its role in apoptosis of CD34+ cells has
not been explored. In this study, we determined whether ICE protein was present
in CD34+ cells and assessed its role in limiting expansion of hematopoietic stem
cells by apoptosis. We demonstrated that ICE mRNA was constitutively produced in
CD34+ cells, although the active form of ICE protein was not detected in fresh,
unstimulated CD34+ cells from healthy donors. ICE protein could be induced in
these CD34+ cells when they were cultured for 24 hours in the presence of
hematopoietic growth factors. Interferon (IFN)-gamma and Fas agonist (CH11
monoclonal antibody) enhanced ICE expression and triggered CD34+ cell apoptosis
and cell death. In both short- and long-term BM cultures, hematopoietic colony
forming cell numbers were increased after ICE blockade with a synthetic ICE
inhibitor (Ac-Tyr-Val-Ala-Asp-aldehyde), even in the absence of IFN-gamma,
suggesting that ICE regulates the proliferation and cell death of committed and
primitive progenitor cells. The suppressive effect of IFN-gamma and Fas agonist
on colony formation was also antagonized by ICE inhibitor. The effects of ICE
blockade on proliferation of hematopoietic progenitors cells were related to
inhibition of apoptosis, as demonstrated by annexin staining and in situ terminal
dideoxytransferase apoptosis assays. Our results suggest that ICE protein is
present in CD34+ cells after exposure to cytokines, that regulation of the levels
of ICE protein in CD34+ cells is posttranscriptional, and that ICE plays a role
in the regulation of apoptosis and expansion of primitive hematopoietic cells.
ICE inhibition could potentially be used to reverse intrinsic and cytokine
mediated apoptotic signals for the purpose of stem and progenitor cell expansion.
PMID- 9766452
TI - About reference citations.
PMID- 9766453
TI - Acknowledging sources in scholarly work.
PMID- 9766454
TI - Predicting pressure ulcer risk: a multisite study of the predictive validity of
the Braden Scale.
AB - BACKGROUND: There have been no studies that have tested the Braden Scale for
predictive validity and established cutoff points for assessing risk specific to
different settings. OBJECTIVES: To evaluate the predictive validity of the Braden
Scale in a variety of settings (tertiary care hospitals, Veterans Administration
Medical Centers [VAMCs], and skilled nursing facilities [SNFs]). To determine the
critical cutoff point for classifying risk in these settings and whether this
cutoff point differs between settings. To determine the optimal timing for
assessing risk across settings. METHOD: Randomly selected subjects (N= 843) older
than 19 years of age from a variety of care settings who did not have pressure
ulcers on admission were included. Subjects were 63% men, 79% Caucasian, and had
a mean age of 63 (+/-16) years. Subjects were assessed for pressure ulcers using
the Braden Scale every 48 to 72 hours for 1 to 4 weeks. The Braden Scale score
and skin assessment were independently rated, and the data collectors were blind
to the findings of the other measures. RESULTS: One hundred eight of 843 (12.8%)
subjects developed pressure ulcers. The incidence was 8.5%, 7.4%, and 23.9% in
tertiary care hospitals, VAMCs, and SNFs, respectively. Subjects who developed
pressure ulcers were older and more likely to be female than those who did not
develop ulcers. Braden Scale scores were significantly (p = .0001) lower in those
who developed ulcers than in those who did not develop ulcers. Overall, the
critical cutoff score for predicting risk was 18. Risk assessment on admission is
highly predictive of pressure ulcer development in all settings but not as
predictive as the assessment completed 48 to 72 hours after admission.
CONCLUSIONS: Risk assessment on admission is important for timely planning of
preventive strategies. Ongoing assessment in SNFs and VAMCs improves prediction
and permits fine-tuning of the risk-based prevention protocols. In tertiary care
the most accurate prediction occurs at 48 to 72 hours after admission and at this
time the care plan can be refined.
PMID- 9766455
TI - Self-report and polysomnographic measures of sleep in women with irritable bowel
syndrome.
AB - BACKGROUND: Women who report chronic gastrointestinal symptoms compatible with a
diagnosis of irritable bowel syndrome (IBS) frequently report sleep disturbances.
OBJECTIVES: The purposes of this study were to (a) compare self-reported and
polysomnographic indicators of sleep quality in women with IBS symptoms (IBS-SX,
n= 16) and controls (n= 16); (b) examine the relationship between the indicators
of sleep quality; and (c) determine the relationship between sleep indicators and
psychological distress. METHOD: The women slept in a laboratory for 2 consecutive
nights. Polysomnographic measurements were recorded during sleep, and a sleep
questionnaire was completed upon awakening each morning. Psychological distress
was measured with the Symptom Checklist-90-R during the initial interview.
RESULTS: Women in the IBS-SX group reported significantly greater numbers of
awakenings during sleep (p = .008) and had a longer latency to REM sleep (p =
.04) than did the controls. Self-reported and polysomnographic indicators were
more highly correlated in the control group than in the IBS-SX group. In the IBS
SX group, the greater the psychological distress, the less alert (rs = .419) and
rested (rs = .564) the women felt in the morning and the more time the women
spent in stages 3 and 4 sleep (rs = .479) and less in stage 2 (rs = -.447) and
REM (rs = -.414) sleep. In the control group, psychological distress was not
significantly associated with self-reported measures but was significantly
associated with the number of awakenings (rs = .506) and time in stages 3 and 4
sleep (rs = -.677). CONCLUSIONS: Although the women in the IBS-SX group reported
significantly more awakenings, the weak relationship between self-reported and
polysomnographic indicators suggests that clinicians must keep in mind that
further assessments may be necessary.
PMID- 9766456
TI - Differences in cortisol, a stress hormone, in women with turmoil-type
premenstrual symptoms.
AB - BACKGROUND: A significant number of American women of childbearing age are
troubled by premenstrual symptoms, but the underlying cause is not understood,
resulting in inadequate therapy. OBJECTIVES: To use basal levels of cortisol to
differentiate women with low symptom (LS) patterns of turmoil-type premenstrual
symptoms from women with premenstrual symptom (PMS) patterns and from women with
premenstrual magnification (PMM) patterns of turmoil-type premenstrual symptoms.
METHOD: Symptom and cortisol patterns of women were monitored for three
consecutive menstrual cycles. Three distinct groups of women were identified
based on symptom patterns and types. RESULTS: Significant differences in symptom
severity among groups were observed during the follicular (F = 203; df= 2, 24; p
< .0001) and luteal phases (F= 51.3; df= 2, 24; p< .0001) of the cycle. There
were no statistically significant differences in cortisol among groups for the
follicular phase, but there were during the luteal phase (F= 4.0; df= 2, 24; p=
.03). CONCLUSIONS: Altered regulation of the stress axis may be involved in
mediating turmoil-type PMS.
PMID- 9766457
TI - A longitudinal causal model of cardiac invalidism following myocardial
infarction.
AB - BACKGROUND: Invalidism has been discussed in the cardiovascular literature for
decades. Researchers have studied health perceptions, emotional distress, and
dependency in patients after acute myocardial infarction in an attempt to
understand the phenomenon. However, no theory of the manner in which these
variables interact has been proposed. OBJECTIVES: Using previous research, a
model of invalidism was specified in which individuals' perceptions that their
health is poor lead to emotional distress and increased dependency. As health
perceptions improve over time, emotional distress and dependency decrease.
METHOD: Survey data were collected from 111 men and women 1 and 4 months after a
first myocardial infarction and were tested using structural equation modeling.
RESULTS: The model was rejected using a confirmatory approach (chi2(89) = 141.40;
p= .00034). The fit indices, however, suggested an adequate fit of the model to
the data (CFI = .96; NNFI = .94). CONCLUSION: The conclusion is that the model is
reasonable and serves as a starting point for a theory-based empirical
exploration of the invalidism process.
PMID- 9766459
TI - The practical effects of errors in reference lists in nursing research journals.
AB - BACKGROUND: Previous studies have noted the prevalence of errors in journal
reference lists, including nursing journals, but an in-depth study of nursing
research journals has not been repeated. OBJECTIVES: The purpose of this study
was to determine the number and types of errors in nursing research journal
reference lists. METHOD: A stratified random sample of 262 references from three
nursing research journals was obtained. References were compared with the actual
articles, books, and chapters cited, or with photocopies obtained via
interlibrary loan. Error rates were calculated. RESULTS: The overall error rate
was 45.8%; 38.3% of all references contained at least one major error, and 13.8%
of all references contained at least one minor error. CONCLUSIONS: The overall
rate of reference errors falls within the range exhibited by recent studies of
the medical and dental literature but exceeds the rates found in studies of
nursing journals and veterinary medicine journals. Researchers need to consider
the number and types of errors involved when using reference lists in their
research.
PMID- 9766458
TI - Effect of positioning on SvO2 in the critically ill patient with a low ejection
fraction.
AB - BACKGROUND: Critically ill patients with a low ejection fraction may be
vulnerable to decreased mixed venous oxygen saturation (SvO2) resulting from
position change. OBJECTIVES: The objectives of this study were to describe the
effects of changes in positioning on SvO2 in critically ill patients with a low
ejection fraction (< or = 30%) and to describe the contribution of variables of
oxygen delivery (DO2) and oxygen consumption (VO2) to the variance in SvO2.
METHOD: An experimental two-group repeated-measures design was used to study 42
critically ill patients with an ejection fraction of less than or equal to 30%
(M= 19.5%). Patients were assigned randomly to one of two position sequences:
supine, right lateral, left lateral; or supine, left lateral, right lateral. Data
on SvO2 were collected at baseline, each minute after position change for 5
minutes, and at 15 and 25 minutes. RESULTS: Repeated-measures multivariate
analysis of variance showed a difference in SvO2 among the three positions across
time (p< .0001), with the greatest differences occurring within the first 4
minutes and in the left lateral position. Stepwise multiple regression showed
that VO2 accounted for a greater proportion of the variance in SvO2 with position
change than did DO2 (54% [p = .001] vs. 31% [p= .001]). CONCLUSIONS: Changes in
SVO2 occur with positioning in critically ill patients with a low ejection
fraction. These changes are transient and are the result of changes in VO2 rather
than changes in DO2.
PMID- 9766461
TI - Spirofungin, a new antifungal antibiotic from Streptomyces violaceusniger Tu
4113.
AB - A new secondary metabolite was detected in the culture filtrate and extracts of
Streptomyces violaceusniger Tu 4113 by HPLC-diode-array and HPLC-electrospray
mass-spectrometry screening. The compound named spirofungin has a polyketide
spiroketal structure and shows various antifungal activities, particularly
against yeasts.
PMID- 9766460
TI - Demethyl mutactimycins, new anthracycline antibiotics from Nocardia and
Streptomyces strains.
AB - New anthracycline antibiotics 3'-O-demethyl mutactimycin (3) and 4-O,3'-O
didemethyl mutactimycin (4) were isolated from two actinomycetes strains,
Nocardia transvalensis and Streptomyces sp. GW 60/1571. The chemical structures
were elucidated by mass spectrometry and NMR spectroscopy. Antibiotic 3 displayed
moderate antimicrobial activity against Gram-positive bacteria and cytotoxicity
against P388, L1210 and HeLa tumor cells (IC50; 9.6, >25 and 20 microg/ml,
respectively).
PMID- 9766462
TI - Hongoquercins, new antibacterial agents from the fungus LL-23G227: fermentation
and biological activity.
AB - Two new antibiotics, hongoquercins A and B, were isolated from fermentation
extracts of the unidentified fungus LL-23G227. In the optimum medium, titers of
the A and B components reached approximately 2.1 g/liter and 0.02 g/liter,
respectively. The optimum temperature for antibiotic production was approximately
22 degrees C. Growth was delayed at 15 degrees C but appeared to reach higher
levels than was observed at 22 degrees C. Addition of dextrose to growth media
increased hongoquercin B production. Hongoquercin A exhibited moderate activity
against Gram-positive bacteria. Mechanistic studies conducted in an E. coli imp
strain suggested membrane damage as the primary mode of bactericidal action.
These compounds also lysed human red blood cells, suggesting a similar mode of
action on eukaryotic cells.
PMID- 9766463
TI - MJ347-81F4 A & B, novel antibiotics from Amycolatopsis sp.: taxonomic
characteristics, fermentation, and antimicrobial activity.
AB - Strain MJ347-81F4 has been found to produce two new cyclic thiazolyl peptide
antibiotics, components A and B. Taxonomic studies including morphological and
physiological characteristics and chemical analysis of whole cells of the
producing strain revealed this microorganism to belong to genus Amycolatopsis,
and so we designated the strain Amycolatopsis sp. MJ347-81F4. After 10 to 12 days
of fermentation, most of the antibacterial activity was present mainly in the
mycelial cake and reached its maximum level. In comparison with reference
compounds, A as the major component showed excellent in vitro activity against
gram-positive bacteria including highly methicillin-resistant Staphylococcus
aureus (MRSA) and Enterococcus faecalis with MICs in the range of concentration
of 0.006 to to approximately 0.1 microg/ml. The results on the antimicrobial
activity against thiazolyl peptide-resistant mutants of Bacillus subtilis NRRL B
558 indicated that the possible molecular target of MJ347-81F4 component A might
be the 50S subunits of the ribosome, the inactivation of which would inhibit
protein synthesis.
PMID- 9766465
TI - The novel enzymatic 3''-N-acetylation of arbekacin by an aminoglycoside 3-N
acetyltransferase of Streptomyces origin and the resulting activity.
AB - Kanamycin group antibiotics were subjected to enzymatic acetylation by a cell
free extract containing an aminoglycoside 3-N-acetyltransferase, AAC(3)-X,
derived from Streptomyces griseus SS-1198PR. Characterization of the incubated
reaction mixtures by TLC and antibiotic assay revealed that a product retaining
activity was specifically formed from arbekacin, an anti-MRSA semisynthetic
aminoglycoside. The structural determination demonstrated that acetylation
occurred at the 3"-amino group in arbekacin and amikacin, and at the 3-amino
group in dibekacin as in the case of kanamycin. These results should reflected
the effect of the (S)-4-amino-2-hydroxybutyryl side chain which is present in
arbekacin and amikacin, but absent in dibekacin and kanamycin. The 3"-N
acetylation is the first finding in the enzymatic modifications of aminoglycoside
antibiotics. 3"-N-Acetylarbekacin showed antibiotic activity as high as that of
2'-N-acetylarbekacin reported previously, whereas 3"-N-acetylamikacin showed no
substantial activity. Thus, our results illuminated a novel aspect of arbekacin
distinct from the other aminoglycosides.
PMID- 9766464
TI - Discovery of MC-02,331, a new cephalosporin exhibiting potent activity against
methicillin-resistant Staphylococcus aureus.
AB - A systematic approach toward building activity against methicillin-resistant
staphylococci into the cephalosporin class of beta-lactam antibiotics is
described. Initial work focused on finding the optimal linkage between the cephem
nucleus and a biphenyl pharmacophore, which established that a thio linkage
afforded potent activity in vitro. Efforts to optimize this activity by altering
substitution on the pharmacophore afforded iodophenylthio analog MC-02,002, which
although highly potent against MRSA, was also highly bound to serum proteins.
Further work to decrease serum protein binding showed that replacement of the
iodo substituent by the positively-charged isothiouronium group afforded potent
activity and reduced serum binding, but insufficient aqueous solubility.
Solubility was enhanced by incorporation of a second positively-charged group
into the 7-acyl substituent. Such derivatives (MC-02,171 and MC-02,306) lacked
sufficient stability to staphylococcal beta-lactamase enzymes. The second
positive charge was incorporated into the cephem 3-substituent in order to
utilize the beta-lactamase-stable aminothiazolyl(oximino)acetyl class of 7
substituents. These efforts culminated with the discovery of
bis(isothiouroniummethyl)phenylthio analog MC-02,331, whose profile is acceptable
with respect to potency against MRSA, serum binding, aqueous solubility, and beta
lactamase stability.
PMID- 9766467
TI - Antibiotic activities and affinities for bacterial cell wall analogue of N
demethylvancomycin and its derivatives.
AB - N-Demethylvancomycin, which has been clinically used in China, is one member of
vancomycin group (glycopeptide) antibiotics. It differs from vancomycin only in
that methyl group on the amino group of the N-terminal residue of vancomycin has
been replaced by H. By reductive alkylation of N-demethylvancomycin, we
synthesized N-alkyl and N,N'-dialkyl N-demethylvancomycins, which closely
correlated with vancomycin in structure. The association constants of the
complexes of N-demethylvancomycin and its analogues with di-N-Ac-L-Lys-D-Ala-D
Ala and the antibiotic activity against Staphylococcus aureus of the
glycopeptides were determined. Results showed that N-demethylvancomycin has
higher affinity for bacterial cell wall analogue di-N-Ac-L-Lys-D-Ala-D-Ala and
more potent antibiotic activity against Staphylococcus aureus than vancomycin.
Both N-alkylation and N,N'-dialkylation of N-demethylvancomycin reduced the
affinity and antibiotic activity. The longer the alkyl groups, the less potent
antibiotic activities and lower affinities have the glycopeptides. The antibiotic
activities against Staphylococcus aureus of N-demethylvancomycin and its
analogues roughly parallel their affinities for di-N-Ac-L-Lys-D-Ala-D-Ala.
PMID- 9766466
TI - Efficacy of syringomycin E in a murine model of vaginal candidiasis.
AB - Syringomycin E (SR-E), a new antifungal produced by the bacterium Pseudomonas
syringae pv. syringae, was evaluated in a murine vaginal candidiasis model. In
one study, mice were treated intravaginally b.i.d. for 4 days with drug carrier,
SR-E 2% in either PEG-400 or PEG-ointment, or 1% clotrimazole as a positive
control. Quantitative vaginal cultures were taken prior to treatment on day 1 and
on days 5, 6, and 7. Both formulations showed a reduction of yeast colonization
in the vaginas on day 5 (P< or =0.06 and P< or =0.03 for SR-E/PEG-400 and SR
E/PEG ointment, respectively) and SR-E/PEG ointment reduced the colonization on
day 7 (P< or =0.06) when compared to carrier treated controls. In a second study,
SR-E was formulated in Aquaphor at three higher concentrations of SR-E [3%, 6%,
or 12% (w/v)]. SR-E showed dose-dependent efficacy. The 3% dose showed no effect
while the 6% and 12% doses reduced the number of yeasts. The 12% dose showed a
significant reduction on days 5 (P< or =0.01), 6 (P< or =0.06), and 7 (P< or
=0.03) when compared with the drug carrier controls and on day 5 was more
effective than clotrimazole (P< or =0.03). Clotrimazole did not significantly
reduce the yeasts in the vagina until days 6 (P< or =0.01) and 7 (P< or =0.01)
when compared to the drug carrier controls. No vaginal inflammatory response was
evident by histological examination in uninfected animals treated with SR-E. No
SR-E could be detected in plasma, kidney, or liver. SR-E (12%) was an effective
treatment when compared to 1% clotrimazole.
PMID- 9766468
TI - Synthesis and structure-activity relationships of 1beta-methylcarbapenems with
quaternary ammonium side chains.
AB - The synthesis and antibacterial activity of 1beta-methylcarbapenems with
quaternary ammonium groups at the C-2 position have been studied. Two types of
new carbapenem derivatives have been synthesized. These 1beta-methylcarbapenems,
one type having a (2S,4S)-2-[1,1-dimethyl-2-(1-piperazinyl)carbonyl]pyrrolidinio
4-+ ++ylthio group and the other type having a (2S,4S)-2-(4-carbamoylmethyl-4
methylhomopiperazinio-1-yl carbonyl)pyrrolidin-4-ylthio group, show potent and
well balanced antibacterial activity as well as high stability against
dehydropeptidase-I. The in vivo potency of these two carbapenems was compared
with that of meropenem. The structure-activity relationships leading to these
carbapenems are also described.
PMID- 9766469
TI - Cladinose analogues of sixteen-membered macrolide antibiotics. VI. Synthesis of
metabolically programmed, highly potent analogues of sixteen-membered macrolide
antibiotics.
AB - Five novel 3-hydroxyl derivatives of sixteen-membered macrolide possessing 4-O
acyl-alpha-L-cladinose as a neutral sugar moiety were synthesized by using a
combination of structurally stable silyl acetal protection and selective
hydrogenolysis of a 3"-methylthiomethyl ether to a 3"-OMe group. Several
derivatives having n-butyryl, i-butyryl and n-valeryl substituent at the 4"-OH
group exhibited significant antibacterial activity in vitro. One of them, 4"-O-n
butyryl-3"-O-methylleucomycin V, showed improved therapeutic effect in mice.
PMID- 9766470
TI - Synthesis and in vitro antibacterial activity of catechol-spiramycin conjugates.
AB - The first synthesis of siderophore conjugates of two macrolide antibiotics,
spiramycin 1 and neospiramycin 2, which are unable to penetrate the outer
membrane of gram-negative bacteria are described. These novel conjugates were
prepared by regioselective acylation of a hydroxyl function of 1 and 2 with a
dihydroxybenzoic Fe(III) complexing ligand linked via a carboxyl group containing
spacer to the macrolide antibiotics. The preliminary biological evaluation of
these novel conjugates under standard and iron depleted conditions has shown that
their antibacterial activity was comparable to that of spiramycin 1 and
neospiramycin 2.
PMID- 9766471
TI - Conversion of spinosyn A and spinosyn D to their respective 9- and 17
pseudoaglycones and their aglycones.
AB - Forosamine at the 17-position of spinosyns A and D was hydrolyzed under mild
acidic conditions to give the corresponding 17-pseudoaglycones. The tri-O
methylrhamnose at the 9-position of the 17-pseudoaglycone of spinosyn A was
hydrolyzed under more vigorous acidic conditions to give the aglycone of spinosyn
A. However, these conditions led to decomposition of the 17-pseudoaglycone of
spinosyn D, presumably due to more facile protonation of the 5,6-double bond to
produce a tertiary carbonium ion which undergoes further rearrangements.
Spinosyns J and L (3'-O-demethyl spinosyn A and D, respectively) obtained from
fermentation of biosynthetically-blocked mutant strains of Saccharopolyspora
spinosa, were oxidized to give the corresponding 3'-keto-derivatives and the
resultant keto-sugars were then beta-eliminated under basic conditions to give
the 9-pseudoaglycones of spinosyns A and D respectively. Forosamine at the 17
position of the 9-pseudoaglycone of spinosyn D was then readily hydrolyzed to
yield the aglycone of spinosyn D.
PMID- 9766472
TI - Effects of tryprostatin derivatives on microtubule assembly in vitro and in situ.
PMID- 9766473
TI - The aluminum reclamation industry work environment: are unidentified neurotoxins
present?
PMID- 9766474
TI - Does work in the aluminum reclamation industry cause neurobehavioral
abnormalities?
PMID- 9766475
TI - Relationship between acute ozone responsiveness and chronic loss of lung function
in residents of a high-ozone community.
AB - We hypothesized that acute respiratory responsiveness to ozone predicts chronic
lung injury from repeated exposure to ozone-containing air pollution. We tested
this hypothesis in 164 middle-aged nonsmoking residents of an ozone-polluted
community who underwent lung-function measurements during 1986 and 1987 (i.e.,
time 3). The time-3 study was a follow up of more comprehensive studies conducted
in 1977-1978 (time 1) and in 1982-1983 (time 2). In contrast to the apparent
rapid (i.e., approximately 60 ml/y) decline in lung-function measurements between
times 1 and 2, our subjects showed little change in forced vital capacity (FVC)
or forced expired volume in 1 s (FEV1.0) between times 2 and 3, and they
experienced a normal decline between times 1 and 3. A subgroup (n = 45) underwent
2-h laboratory ozone exposures to 0.4 ppm ozone, accompanied by intermittent
exercise, and they experienced mild acute reductions in FEV1.0 and FVC, but there
was little change in bronchial responsiveness to methacholine. Individual acute
responses to laboratory ozone were not correlated with individual long-term
changes between times 1 and 3. In summary, the results did not support our
initial hypothesis, and they did not confirm rapid function decline in nonsmokers
chronically exposed to ozone-containing air pollution.
PMID- 9766476
TI - Short-term effects of low-level winter pollution on respiratory health of
asthmatic adults.
AB - We studied the short-term effects of Paris winter air pollution (i.e., sulfur
dioxide, Black Smoke, suspended particulates with an aerodynamic diameter close
to 10 microm, and nitrogen dioxide) in 40 nonsmoking mild to moderate asthmatics
(52% male; mean age = 46 y; 90% treated with inhaled steroids). During a 6-mo
period, subjects recorded asthma symptoms and three daily peak expiratory flow
measurements. Statistical analysis (i.e., generalized estimating equation models
that accounted for autocorrelation of responses, weather data, and time trends)
revealed consistent and significant associations between the pollutants and
asthma attacks and symptoms in the entire study group, especially in the subgroup
of individuals who took inhaled beta2 agonists as needed. Pollutants correlated
negatively with morning peak expiratory flow in the subgroup that took inhaled
beta2 agonists as needed, and they correlated positively with daily variability
in asthmatics who received regularly scheduled inhaled beta2 agonists. The
effects lingered several days after exposure occurred. Low-level pollution has
consistent measurable effects on nonsmoking adults who have well-treated mild or
moderate asthma.
PMID- 9766477
TI - Neurobehavioral impairment and symptoms associated with aluminum remelting.
AB - The author's objective was to assess whether aluminum reclamation (recycling)
exposure in a plant in the southeastern United States was associated with
neurobehavioral and pulmonary impairment and symptoms. The author made cross
sectional comparisons of 41 workers to 32 local and 66 regional referents to
assess whether aluminum recycling was associated with neurobehavioral and
pulmonary impairment and symptoms. Methods included neurophysiological,
psychological, and pulmonary-function tests; a Profile of Mood States (POMS); and
questionnaires. The exposed subjects had slower simple and choice reaction times
than referents (i.e., 77 milliseconds [ms] versus 137 ms, respectively [p <
.0001]); balance in the exposed subjects, measured as sway speed (with eyes
closed), was .32 cm/s faster than for referents (p < .005); and color
discrimination was less acute in exposed subjects (p < .0001). In the exposed
versus referent subjects, Culture Fair scores were lower by a factor of 8.3 (p <
.0001), Trail Making A was 10 s longer (p < .001), Trail Making B was 50 s longer
(p < .0001), peg placement required an additional 9 s (p < .008), and POMS scores
were fourfold higher (p < .0001). These described differences were not explained
by age, bias, or confounding factors. Workers had more neurobehavioral,
rheumatic, and respiratory symptoms than did referents. The author attributed the
differences between the two groups to chemical exposures from aluminum remelting,
including aluminum, manganese, vinyl chloride monomer, and other chemicals.
Workplace air could not be sampled, but because a problem was identified, levels
of these, as well as other chemicals, should be measured in future studies.
PMID- 9766478
TI - Cancer incidence and risks in selected agricultural settlements in the Negev of
Israel.
AB - Medical staff of two Negev kibbutzim invited epidemiologists to help them
investigate cancer rates among their members. Our objectives were (a) to
determine whether the cancer rate in the kibbutzim was elevated or abnormal and
(b) to determine the role of agricultural and other relevant exposures if cancer
incidence was elevated. We validated cases of cancer by kibbutz records and by
surveying other information; we computed expected values on the basis of the age
sex-calendar period and site-specific cancer incidence rates reported by the
Israel Cancer Registry for the entire population; and we compared the data for
the 2 kibbutzim with data derived for similar age and sex groups in 2 other
kibbutzim, which were assumed not to have increased cancer rates. In addition, we
planned and conducted a case-referent study, including the design, pretest, and
use of questionnaires, including data about lifetime exposures (i.e., type of
work and its duration, agricultural and industrial chemicals, smoking and alcohol
use, demographic variables, health experiences, and family history). In only one
of the kibbutzim, for which high cancer rates were suspected, was there
significant excess for all sites in persons who were less than 40 y of age. In
one of the "comparison" kibbutzim, we found increased cancer rates overall. Much
of the excess in the high cancer kibbutzim was in hematological cancer (i.e.,
leukemia and lymphoma). Multiple years of work in fields, orchards, and
landscape, as well as orchard work that commenced before 1960, were associated
with increased risk of cancer (p < .08). We also found an association between
cancer rate and numbers of industrial chemicals used (p < .08). Pipe and
cigarette smoking were also associated with increased cancer incidence. In the
multivariate analysis, the association with calendar year in which orchard work
was started and multiple exposures to industrial chemicals was stronger than
associations noted in the univariate analyses. Although duration of agricultural
work or multiple industrial exposures were clearly associated with increase in
cancer risk, we were unable to identify the causal role of specific agent(s).
Nonetheless, educational programs for cancer prevention can be based, in part, on
the results of such a study.
PMID- 9766479
TI - Children exposed to chronic contamination after the Chernobyl accident:
cytogenetic and radiotoxicological analyses.
AB - In this study, we describe cytogenetic studies of lymphocytes obtained from
children who were exposed after the Chernobyl accident to low doses of ionizing
radiation. We sought to determine possible chromosomal damage relative to
internal contamination, as measured by whole-body counter and urine
radiotoxicological analyses. The study was performed during a 1-mo period on the
peripheral blood of children hosted in Italy, but who resided in contaminated
regions of the Russian Federation and Belarus. We used conventional cytogenetics
to detect chromosomal aberrations. In some cases, we also used "chromosome
painting" to look for stable aberrations. There were more acentric fragments in
subjects than in controls; a few chromosome and chromatid breaks werefound in the
subjects, but this finding did not differ significantly between subjects and
controls.
PMID- 9766481
TI - Reactive Intestinal Dysfunction Syndrome (RIDS) caused by chemical exposures.
AB - In this study, the authors describe a new "reactive syndrome," Reactive
Intestinal Dysfunction Syndrome (RIDS), which has similarities to the previously
described clinical syndromes Reactive Airway Dysfunction Syndrome (RADS) and
Reactive Upper Airway Dysfunction Syndrome (RUDS). Given that at least 5
neuropeptides are common to both the respiratory tract and digestive tract, the
authors propose that the abnormal secretion of these neuropeptides or the
abnormal numbers of their receptors play a role in what is perceived clinically
as RADS, RUDS, and RIDS. The relatively large surface areas of both the lungs and
gut render them especially vulnerable to the environment to which they are
exposed constantly.
PMID- 9766480
TI - Increased cardiopulmonary disease risk in a community-based sample with chemical
odor intolerance: implications for women's health and health-care utilization.
AB - Chemical intolerance, or reported illness from odors of common environmental
chemicals (e.g., car exhaust, pesticides), is emerging as an important
environmental and public health-care issue. Epidemiologic methods provide
relevant heuristic devices for studies of complex disorders, such as chemical
intolerance. The authors examined personal and reported parental cardiopulmonary
disease prevalence rates in a community sample of chemically intolerant and
control individuals. A county government (Tucson, Arizona) employee and kin
subset (N = 181; 113 households) completed standard health questionnaires.
Investigators determined chemical intolerance (n = 41/181) from self-reports of
individuals who felt "moderately" to "severely" ill from exposure to at least
three of five chemicals (i.e., car exhaust, pesticides, paint, new carpet, and
perfume) on a Chemical Odor Intolerance Index. The authors chose the control
group (n = 57/181) on the basis of self-reports of "never" feeling ill on the
Chemical Odor Intolerance Index. The chemically intolerant group, which primarily
comprised women (78% versus 51% of controls, p < .05), was significantly more
likely to report-and to have sought--medical attention for heart problems,
bronchitis, asthma, and pneumonia. Reports of heart problems in the chemically
intolerant index cases and the occurrence of heart disease in both of their
parents were significant (Fisher's p < .05). The chemically intolerant
individuals were also significantly more likely to report maternal histories of
chest problems (e.g., inhalant allergens, tuberculosis) than controls. The
findings of the study suggested that the chemically intolerant individuals (a
preponderance of whom were women [sex-related risk]) were more likely to have (a)
reported cardiopulmonary problems (i.e., greater health risk); (b) actively
sought medical care for these problems (i.e., increased medical utilization); and
(c) reported more parental illnesses-particularly heart disease, asthma, and
diabetes (i.e., genetic risk). Additional community-based studies of chemical
intolerance are needed.
PMID- 9766482
TI - Exposure to power frequency magnetic fields and risk of breast cancer in the
Upper Cape Cod Cancer Incidence Study.
AB - Investigators used a population-based case-control study to evaluate the
relationship between breast cancer risk and exposure to 60-Hz magnetic fields
from various sources. There was no increase in breast cancer risk associated with
(a) holding a job with high (odds ratio [OR] = 1.2; 95% confidence interval [CI]
= 0.4, 3.4) or medium (OR = 0.9; 95% CI = 0.5, 1.7) exposure to magnetic fields;
(b) living in a home heated electrically (OR = 1.0; 95% CI = 0.7, 1.4); or (c)
sleeping with an electric blanket (OR = 1.0; 95% CI = 0.7, 1.4). There was a
nonsignificant 50% increase in risk for subjects who lived within 152 m (500 ft)
of an electricity transmission line or substation (OR = 1.5; 95% CI = 0.6, 3.3).
Although limited by small numbers and exposure misclassification, the data in
this study did not support the hypothesis that exposure to 60-Hz magnetic fields
increases the risk of breast cancer in women.
PMID- 9766483
TI - The histopathology of ankylosing spondylitis: are there unifying hypotheses?
AB - This article examines some fundamental features of the histopathology of
ankylosing spondylitis (AS) such as inflammation in the entheses and
syndesmophyte formation. This may be linked to the generation of transforming
growth factor in inflammation, which can stimulate bone formation, and to the
molecular composition of entheses where molecules are present, such as the
proteoglycan aggrecan, that are normally found in cartilage. Immunity to these
molecules is observed in patients with AS and in experimental immunity to
aggrecan, or the G1 domain only, which can cause spondylitis. Involvement of
other tissues (the eye and arterial vessels) may be due to crossreactive
immunity.
PMID- 9766484
TI - Clinical aspects of the spondyloarthropathies.
AB - The spondyloarthropathies are a group of inflammatory arthritic conditions
characterized by the absence of rheumatoid factor, and the presence of
spondylitis, sacroiliitis, and an asymmetric peripheral arthritis. Familial
aggregation and the presence of enthesitis, skin and mucous membrane lesions,
bowel complaints, eye involvement, and aortic root dilatation are also features
of these conditions. An association with HLA-B27 has been documented in the
diseases constituting the spondyloarthropathies, including ankylosing
spondylitis, Reiter's disease/reactive arthritis, psoriatic arthritis, and the
arthritis of inflammatory bowel disease. Although there are similarities among
the entities included in this group, each of these conditions have specific
characteristics that help distinguish them. Differences in response to
medications and in prognosis are such that it is important to make the correct
diagnosis in the individual patient.
PMID- 9766485
TI - HLA-B27 and the seronegative spondyloarthropathies.
AB - In the 25 years since the initial reports of the association of HLA-B27 with
ankylosing spondylitis (AS) and subsequently with Reiter's syndrome, psoriatic
spondylitis, and the spondylitis of inflammatory bowel disease, the association
of HLA-B27 with the seronegative spondyloarthropathies has remained one of the
best examples of a disease association with a hereditary marker. HLA-B27 has been
recognized as representative of a spectrum of diseases, ranging from the majority
of HLA-B27-positive individuals who have no disease at all, through those with
isolated eye or skin involvement, to those with critical eye, heart, and
peripheral joint compromise of full-blown AS. Yet HLA polymorphism has evolved in
response to environmental stresses, and even the presence of HLA-B27 itself
appears to confer advantages in certain infectious diseases, such as acquired
immune deficiency syndrome (AIDS). This article will review what is currently
known about HLA-B27 and disease, especially in the seronegative
spondyloarthropathies. The structure-function relationship of HLA-B27 will be
presented, including differences between the B27 subtypes both in their ethnic
variation and possible disease implications. The disease spectrum conferred by
the presence of HLA-B27 will also be discussed, and the theories of how HLA-B27
contributes to the pathogenesis of the spondyloarthropathies will be considered.
PMID- 9766486
TI - Arthritis in HLA-B27 transgenic animals.
AB - This review focuses on investigations of rats and mice transgenic for HLA-B27;
these animals have been investigated for several years as potential models for
the human spondyloarthropathies. Spontaneous multisystem disease occurs in rats
with high expression of B27 and human beta2-microglobulin (hbeta2m). The disease
is T-cell-dependent and is sensitive to both environmental and genetic
manipulation. A spontaneous arthritis and enthesopathy has been observed by some
investigators in nontransgenic mice which seems to be more prevalent in B27
transgenic mice. Peripheral arthritis has also been reported in B27 transgenic
mice that lack mouse beta2m. Potential insights from these animals into the
pathogenesis of B27-related disease are discussed.
PMID- 9766487
TI - The pathogenesis of HLA-B27 arthritis: role of HLA-B27 in bacterial defense.
AB - The way in which a host accommodates invasive facultative intracellular bacteria
must be the key to the development of reactive arthritis. Investigators have
analyzed the bacterial events at several levels: invasion into host cells,
intracellular survival, translocation from the sites of infection to the joints,
residence in the joints, and evasion of host defense. Because HLA-B27 is present
in higher incidence in patients with reactive arthritis and is an essential gene
in the related ankylosing spondylitis, the role of HLA-B27 in host defense is
also assumed to be important in the development of reactive arthritis. This
review summarizes the various studies in this field.
PMID- 9766488
TI - Infectious agents as triggers of reactive arthritis.
AB - Reactive arthritis was originally defined as a sterile joint inflammation after
infection elsewhere in the body, but this view has been challenged in the past
decade since different antigens and DNA and RNA of various triggering microbes
have been shown to exist at the sites of inflammation in the joints. It has been
suggested that microbial antigens, or intact pathogens, are important for the
pathogenesis of reactive arthritis, at least in the early phase of the disease,
but the exact mechanism of how the pathogens contribute to the development of
this usually self-limiting polyarthritis has not been discovered. This article
reviews the theories on the role of infectious agents as triggers of reactive
arthritis.
PMID- 9766489
TI - Insights into the pathogenesis of psoriasis and psoriatic arthritis.
AB - Psoriasis and its related arthritis are chronic inflammatory disorders affecting
predominantly the skin and synovium. Although their etiology remains to be
established, multiple factors seem to play important roles in their pathogenesis.
These environmental (eg, infectious agents and trauma), genetic, and immunologic
factors are reviewed in this article.
PMID- 9766490
TI - A multicenter study of the prevalence and susceptibility patterns of isolates of
Streptococcus pneumoniae with reduced susceptibility to penicillin G in
Louisiana.
AB - Because of increasing reports of multiple-antibiotic-resistant strains of
Streptococcus pneumoniae and associated clinical failures, this study was
performed to determine the prevalence of multiresistance among strains from nine
Louisiana medical centers. Using a National Committee for Laboratory Standards
broth microdilution method, 481 strains were tested. Of these, 70% were
penicillin-susceptible (PS), 23% had intermediate minimum inhibitory
concentration values to penicillin (I), and 7% were fully resistant to penicillin
(PR). The isolation rates (15% to 40% for I strains and 0% to 33% for PR strains)
at the various medical centers varied appreciably. The prevalence of penicillin
resistance was highest among upper respiratory isolates, while cross-resistance
to other antimicrobials varied. The least cross-resistance was noted among PS
strains. However, strains with reduced penicillin susceptibility had high levels
of cross-resistance. Among I strains, the prevalence of cross-resistance (%) was
noted for amoxicillin/clavulanate (6%), cefuroxime (71%), cefaclor (91%),
ceftriaxone (13%), cefotaxime (34%), erythromycin (67%), azithromycin (32%), and
clarithromycin (32%). For PR strains, the prevalence of cross-resistance was 97%
for amoxicillin/clavulanate, cefuroxime, and cefaclor; 67% for ceftriaxone and
erythromycin; 89% for cefotaxime; and 69% for azithromycin and clarithromycin.
These data emphasize the high prevalence of multiple-antimicrobial-resistance
among strains of S pneumoniae with reduced penicillin susceptibility in this
geographic area.
PMID- 9766491
TI - Esophageal papillomatosis from human papilloma virus proven by polymerase chain
reaction.
AB - Human papilloma viruses (HPVs) are known to infect the genitourinary tract, the
skin, the anal canal, and the upper respiratory tract. Esophageal papillomas and
especially HPV-induced squamous papillomas of the esophagus are rare. The authors
report a case of extensive HPV-induced esophageal polyposis, which was probably
sexually transmitted. The 53-year-old female patient presented with chronic
diarrhea and had occult blood in the stool. She underwent
esophagogastroduodenoscopy, at which time multiple esophageal polyps were
observed and biopsy specimens obtained. Histologic evaluation was consistent with
benign papillomas. Polymerase chain reaction and DNA hybridization of the
biopsied tissue specimens confirmed the diagnosis of HPV infection. Because of
our observation and because of HPV's relationship to cervical and esophageal
cancer, further evaluation of HPV as the cause of esophageal papillomatosis and
as a risk factor for esophageal cancer is warranted.
PMID- 9766492
TI - Lymphoma cell lines: in vitro models for the study of HHV-8+ primary effusion
lymphomas (body cavity-based lymphomas).
AB - Primary effusion lymphoma (PEL; also known as body cavity-based lymphoma) is
recognized as a new and unique lymphoma entity occurring predominantly, but not
exclusively in human immunodeficiency virus (HIV)-seropositive patients with
acquired immunodeficiency syndrome (AIDS). PEL grows exclusively in body cavities
as serous lymphomatous effusion without evidence of mass disease or
dissemination. Their most unique feature is infection with the newly discovered
human herpesvirus-8 (HHV-8; also known as Kaposi's sarcoma-associated
herpesvirus), often accompanied by co-infection with Epstein-Barr virus (EBV). A
number of continuous lymphoma cell lines have been established from the malignant
pleural effusion, ascitic fluid and peripheral blood of patients with AIDS- and
non-AIDS-associated PEL. While all cell lines are HHV-8+, about half of them also
contain EBV sequences. Stimulation of the cell lines causes switch from latent to
lytic HHV-8 infection. The cells are generally negative for T and B cell
immunomarkers (except for CD138 suggesting a pre- or terminal plasma cell stage)
and positive for some activation and adhesion markers; they are genotypically B
cells with their immunoglobulin genes rearranged. Complex, hyperdiploid
karyotypes with multiple structural abnormalities are seen in the cell lines
examined. No alterations of known proto-oncogenes are detected in PEL, with the
exception of BCL-6 mutations occurring in a large percentage of cases.
Heterotransplantation of the cell lines into immunodeficient mice leads to the
development of lymphomatous effusion and marked angiogenesis. As HHV-8 contains
DNA sequences of several protein homologues, the cell lines express various
cytokines, cytokine receptors, chemokines, cell cycle and anti-apoptosis
modulators which are upregulated upon stimulation. Indeed, some cell lines
produce high levels of (human) interleukin-6 and interleukin-10. Taken together,
these cell lines represent very important model systems for the elucidation of
the pathobiology of PEL; furthermore, the cell lines are extremely useful
scientific tools providing a resource to pursue studies of HHV-8-mediated
pathogenic mechanisms.
PMID- 9766493
TI - Clinical study of 9-cis retinoic acid (LGD1057) in acute promyelocytic leukemia.
AB - The use of all-trans retinoic acid (RA) for remission induction markedly
increases survival of patients with acute promyelocytic leukemia (APL) compared
to patients treated solely with cytotoxic chemotherapy. However, clinical
resistance to this agent develops rapidly, which has been associated with a
progressive decline in plasma drug concentrations. Previous studies suggested
that 9-cis RA, a retinoid receptor 'pan agonist' did not induce its own
catabolism to the same extent as all-trans RA. Therefore, we conducted a dose
ranging study of this compound in patients with both relapsed and newly diagnosed
APL. We treated 18 patients with morphologically diagnosed APL (13 relapsed, five
newly diagnosed). The daily dose of 9-cis RA ranged from 30 to 230 mg/m2/day
given as a single oral dose. Four of 12 (33%) relapsed patients (three of whom
were previously treated with all-trans RA) and four of five (80%) newly diagnosed
patients achieved complete remission. The sole failure in the newly diagnosed
group died early from an intracranial hemorrhage. One other patient with t(9;12)
translocation had substantial hematologic improvement. The drug was generally
well tolerated; headache and dry skin were the most common adverse reactions.
Three patients were treated with corticosteroids for signs of incipient 'RA
syndrome.' These preliminary data suggest that 9-cis RA is an effective agent for
remission induction and deserves further investigation in patients with retinoid
sensitive APL.
PMID- 9766494
TI - Combination of aclarubicin and etoposide for the treatment of advanced acute
myeloid leukemia: results of a prospective multicenter phase II trial. German AML
Cooperative Group.
AB - In order to develop new strategies for the treatment of relapsed or refractory
acute myeloid leukemia, the German AML Cooperative Group performed a prospective
multicenter phase II study to evaluate the antileukemic efficacy of aclarubicin
60 mg/m2/day and etoposide 100 mg/m2/day each given for 5 days. Of 37 heavily
pretreated evaluable patients (median age 42 years, range 18-81) 15 (40%)
achieved a remission after one or two courses of treatment consisting of nine
complete (24%) and six partial remissions (16%). Fourteen (38%) cases were non
responders and eight (22%) patients suffered from early deaths. Disease-free
survival for patients in remission and overall survival were 3.2 months each. The
median duration of critical neutropenia <500/microl was 27 days. The most
frequent non-hematologic side-effects were stomatitis (WHO III/IV, 48%),
infections (40%), nausea/vomiting (26%) and diarrhea (24%). Cardiac toxicity was
mild. This study suggests a substantial antileukemic efficacy and an acceptable
toxicity of aclarubicin in combination with etoposide in heavily pretreated
patients with advanced acute myeloid leukemia, and warrants further evaluations
in a more favorable stage of the disease.
PMID- 9766495
TI - Anti-asparaginase antibodies following E. coli asparaginase therapy in pediatric
acute lymphoblastic leukemia.
AB - Asparaginase is an effective antileukemic agent and is included in most front
line protocols for pediatric acute lymphoblastic leukemia (ALL) worldwide;
however, allergic reactions to asparaginase may be dose-limiting. We evaluated
plasma anti-asparaginase antibody concentrations in a cohort of children with
newly diagnosed ALL, who did and who did not exhibit clinical hypersensitivity,
after Escherichia coli (E. coli) asparaginase therapy. Thirty-five children who
received asparaginase 10000 IU/m2 i.m. three times weekly for nine doses as part
of both multiagent induction and reinduction chemotherapy, and seven monthly
doses during the first 7 months of continuation treatment, were studied. Twenty
two patients experienced initial allergic reactions to asparaginase during
continuation (n=20) or reinduction (n=2) phases and 13 children did not exhibit
any reaction. An enzyme-linked immunosorbent assay (ELISA) was used to measure
anti-asparaginase antibodies in plasma samples, diluted 1:3200, using E. coli
asparaginase as the antigen. The median anti-asparaginase antibody concentration
(OD at 1:3200 dilution) increased from 0.039 at induction to 0.506 at reinduction
in patients who exhibited clinical hypersensitivity (P = 0.0002). By comparison,
median antibody level increased from 0.011 to 0.032 OD at identical time points
in patients who did not react to asparaginase (P = 0.02). Both post-induction and
post-reinduction anti-asparaginase antibody levels were higher in reacting than
in nonreacting patients (P = 0.004 and P = 0.01, respectively). Antibody levels
were inversely related to the time elapsed between the reaction and sampling (P =
0.011). Although anti-asparaginase antibody levels increased from the post
induction plasma sample to the post-reinduction sample in 28 of 35 patients
regardless of whether they exhibited clinical hypersensitivity, patients with
hypersensitivity reactions had higher antibody levels than did identically
treated control patients at comparable time points in therapy. Therefore,
antibody analysis may be of clinical value in predicting future hypersensitivity.
PMID- 9766497
TI - Characterization of H+-ATPase-dependent activity of multidrug resistance
associated protein in homoharringtonine-resistant human leukemic K562 cells.
AB - Multidrug resistance (MDR), caused by overexpression of either P-glycoprotein or
the multidrug resistance-associated protein (MRP), is characterized by a
decreased cellular drug accumulation due to an enhanced drug efflux. Many studies
on cells overexpressing MRP and/or Pgp, have shown a concentration of the drug
inside cytoplasmic acidic vesicles followed by an exocytotic process. In this
study, we examined the effects of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole or NBD
(a H+-ATPase pump inhibitor), buthionine sulphoximine or BSO (an inhibitor of
glutathione (GSH) biosynthesis) and verapamil or VPL (a calcium channel blocker)
on the subcellular distribution of daunorubicin or DNR in K562 cells
overexpressing MRP (K-H30) and Pgp (K-H300) and A549 cells overexpressing
spontaneously MRP. Nucleo-cytoplasmic distribution of DNR was carried out using
scanning confocal microspectrofluorometry. This technique allows determination of
nuclear accumulation of anthracyclines. Our results show that nuclear
accumulation of DNR in K-H30 and A549 cells was increased by NBD, BSO and VPL
while in K-H300 cells, only VPL was able to increase nuclear accumulation of DNR.
Similarly, NBD, BSO and VPL could reverse DNR resistance in K-H30 cells whereas,
in K-H300 cells, only VPL increased the sensitivity of these cells. These data
suggest a requirement for GSH in MRP-mediated resistance and suggest that even if
vesicular sequestration can happen in cells overexpressing MRP and Pgp proteins,
probably only the MRP protein is able to extrude the drug through intracellular
vesicles and efflux. Finally, NBD and BSO might be a useful agents in
facilitating discrimination between Pgp and MRP phenotypes and prognosis in
patients.
PMID- 9766496
TI - Duration of first remission predicts remission rates and long-term survival in
children with relapsed acute myelogenous leukemia.
AB - Although treatment of childhood acute myelogenous leukemia (AML) has
substantially improved in the last 15 years, in nearly half of the patients
disease recurs. The aim of this study was to establish the prognosis of relapsed
childhood AML and to identify prognostic factors for achievement of second
remission and survival. From February 1988 to July 1996, 134 children with first
relapse of AML were reported to the study center of the AML-BFM group. 102
patients treated intensively to induce second remission were prospectively
followed. With various regimens, complete remission was achieved in 52 of 102
patients (51%), 27 children were alive in median 2.5 years (range, 0.4-7 years)
after relapse. Disease-free survival was observed in seven of 16 patients
transplanted from a matched sibling donor, one of four after matched unrelated
bone marrow transplantation, 10 of 22 after autologous transplantation and five
of nine patients after chemotherapy alone (two patients were lost to follow-up).
Time until relapse reflecting the duration of first remission is the only
variable correlating CR and survival rates. Defining early relapse as less than
1.5 years from diagnosis to relapse resulted in a 5-year survival of 10%, s.e. 5%
for early relapses and 40%, s.e. 10% for late relapses (P-logrank test, 0.0001).
Duration of first remission is a strong predictor for achievement of second CR
and survival. It should be considered in reporting results of experimental
therapies.
PMID- 9766498
TI - Antileukemic action of buthionine sulfoximine: evidence for an intrinsic death
mechanism based on oxidative stress.
AB - The glutathione-depleting agent buthionine sulfoximine (BSO) was found to be
toxic to some AML blast populations. This toxicity was manifested as the
appearance of high levels of reactive oxygen generation in GSH-depleted cells,
and later by the loss of mitochondrial membrane potential and an increase in
intracellular calcium. Striking heterogeneity in BSO sensitivity was observed in
a series of four human AML cell lines, and in fresh leukemic blasts obtained from
eight AML patients. In some cases, toxicity was seen at BSO concentrations as low
as 1 microM; approximately 100-fold less than the plasma levels achieved in
patients treated with BSO as a drug resistance reversing agent. Based on these
results we propose that some AML blast populations are unusually dependent on GSH
based antioxidant mechanisms, due to high intrinsic rates of reactive oxygen
generation. The mitochondrial respiratory chain is the most likely source of this
reactive oxygen. Because toxicity is seen at clinically achievable concentrations
of BSO, this agent might have antileukemic activity in patients.
PMID- 9766499
TI - Processing/activation of caspases, -3 and -7 and -8 but not caspase-2, in the
induction of apoptosis in B-chronic lymphocytic leukemia cells.
AB - Chlorambucil and prednisolone, two commonly used drugs in the treatment of
chronic lymphocytic leukemia (CLL), induce apoptosis in CLL cells. We have
investigated the involvement in this apoptotic cell death of caspases, which
cleave critical cellular substrates thereby acting as the executioners of the
apoptotic process. Induction of spontaneous or chlorambucil/prednisolone-induced
apoptosis of freshly isolated B-CLL cells in culture resulted in the activation
of the 'effector' caspases, -3 and -7, but generally not of caspase-2. Activation
of caspases-3 and -7 was accompanied by the proteolysis of the DNA repair enzyme,
poly (ADP-ribose) polymerase. Induction of apoptosis was also accompanied by the
processing of caspase-8, the extent of which varied between patients. Induction
of apoptosis and processing of all the caspases was inhibited by the cell
permeable caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethyl
ketone (Z-VAD.fmk). Our results demonstrate a key role for the activation and
processing of caspases in the execution phase of apoptosis in CLL cells.
Apoptosis of CLL cells resulted in the selective activation of some but not all
caspases. Our results suggest that the dysregulation of apoptosis observed in CLL
may be due to the signalling leading to the activation of caspases rather than a
deletion of pro-caspases. High levels of caspase-8 in CLL cells in conjunction
with low levels of CD95 receptor may offer new therapeutic opportunities for the
treatment of CLL.
PMID- 9766500
TI - Resistance of t(4;11) (MLL-AF4 fusion gene) leukemias to stress-induced cell
death: possible mechanism for extensive extramedullary accumulation of cells and
poor prognosis.
AB - Acute leukemias of the t(4;11) (MLL-AF4 fusion gene) type frequently have high
white blood counts and extramedullary disease in multiple organs. In the present
study we evaluated the hypotheses that this extensive disease is the result of
extramedullary survival of leukemia cells due to resistance to stress-induced
cell death. Leukemias with t(4;11)(MLL-AF4) were found to be resistant to the
cell death that results from serum deprivation in vitro when compared with B
lineage acute leukemias without t(4;11)(MLL-AF4). Cells with t(4;11)(MLL-AF4) did
not have increased doubling time or increased numbers of cells in cycle. These
results suggest that the alteration in cellular homeostasis in these leukemias is
due to abnormalities of cellular destruction rather than cellular proliferation
when compared to other leukemias. Our results are consistent with the hypothesis
that death of non-t(4;11) leukemias occurs in the microenvironment outside of the
bone marrow as a result of deficient cellular and humoral growth factors.
Resistance to death signals in t(4;11) leukemias results in extensive
accumulation of leukemia cells in extramedullary sites and likely contributes to
the poor prognosis of these leukemias.
PMID- 9766501
TI - Induction of sensitivity to NK-mediated cytotoxicity by TNF-alpha treatment:
possible role of ICAM-3 and CD44.
AB - SR-91 is a natural killer (NK)-resistant leukemic cell line expressing a low
level of ICAM-1. Pre-treatment of SR-91 cells with TNF-alpha or IFN-gamma,
increased both ICAM-1 (CD54) expression on SR-91 cells and binding to the human
NK cell line NK-92. However, only TNF-alpha-treated SR-91 cells became sensitive
to killing by NK-92 cells. The increased binding induced by both cytokines and
the TNF-alpha-induced sensitivity of SR-91 cells to NK-92 cell killing were
abrogated by anti-LFA-1 mAb as well as by a combination of antibodies against the
three ligands of LFA-1 (CD11a/CD18), ICAM-1 (CD54), ICAM-2 (CD102) and ICAM-3
(CD50). This indicated that LFA-1 interaction with the three ICAMs on SR-91 cells
is essential for effector-target cell binding (which is a prerequisite for
subsequent target cell lysis), but is insufficient to render the SR-91 cells
sensitive to killing by NK-92 cells. TNF-alpha, but not IFN-gamma also induced
the activation of LFA-1, CD44 and beta1 integrins on SR-91 cells. Based on these
observations we propose that the differential effect of TNF-alpha and IFN-gamma
could be related to the activation of certain adhesion molecules on the surface
of SR-91 cells by TNF-alpha that, upon interaction with their counter-receptors
on NK-92 cells, lead to the activation of the NK-92 cells.
PMID- 9766502
TI - CD57+/CD28- T cells in untreated hemato-oncological patients are expanded and
display a Th1-type cytokine secretion profile, ex vivo cytolytic activity and
enhanced tendency to apoptosis.
AB - Three-color flow cytometry immunophenotyping revealed significant increases of
CD57+ and CD28- cells among both circulating CD4+ and CD8+ T lymphocytes of
untreated hemato-oncological patients (n = 54) as compared to healthy donors (n =
55), with CD57 and CD28 expression on the patients' T cells being largely
reciprocal. Marked expansion of CD57+ cells among circulating CD4+ T lymphocytes
was frequently detected in patients with chronic leukemia of B cell origin (B
CLL, hairy cell leukemia) but not in patients with chronic myeloid leukemia,
suggesting a causal relation with the tumor's major histocompatibility complex
class II expression. Using immunomagnetic separation techniques, we further
demonstrate that the patients' CD57+/CD28- T cells display a typical Th1-type
cytokine secretion profile upon anti-CD3 stimulation, with a markedly higher
secretion of the Th1-type cytokines IL-2, IFN-gamma, and TNF-alpha than their
CD57-/CD28+ counterparts. Cytotoxic activity of circulating CD8+ T lymphocytes,
measured ex vivo in an anti-CD3-redirected assay, was almost exclusively exerted
by the CD57+/CD28- subset. Moreover, a marked cytotoxic activity was detected
within CD4+CD57+ T cells from some B-CLL patients. Finally, the patients'
CD57+/CD28- T cells displayed an increased tendency to apoptosis in culture.
Collectively, our results indicate that the expanded CD57+/CD28- T cells in
hemato-oncological patients represent differentiated effector cells, similar to
their (quantitatively minor) counterpart in healthy donors. The reason for their
expansion and their pathophysiologic significance, however, remains unclear.
PMID- 9766503
TI - A cell surface molecule, JL1; a specific target for diagnosis and treatment of
leukemias.
AB - We previously reported a novel differentiation antigen, which is specifically
expressed in stage II double positive (CD4+CD8+) human cortical thymocytes (Park
et al, J Exp Med 1993; 178: 1447-1451). This study was designed to investigate
the expression pattern of JL1 in various types of leukemic cells from patients
and normal hematopoietic cells to evaluate the possibility as a tool for
diagnosis and treatment of leukemia. The expression of JL1 antigen was observed
in 75.6% of leukemic cases (117 out of 154 leukemic patients tested) on flow
cytometric analysis. The percentage of JL1-positive cases of T lineage acute
lymphoblastic leukemia (T-ALL) (92.6%) was higher than that of other types of
leukemias (75%). The presence of JL1 antigen was also confirmed by immunoblotting
and immunoprecipitation. Since the JL1 antigen is selectively expressed on the
surface of human leukemic cells but not on the mature human peripheral blood
cells, normal bone marrow cells and various types of normal tissues, JL1 could be
an excellent candidate for an immunodiagnostic and immunotherapeutic tool for
hematopoietic malignancies such as leukemia.
PMID- 9766504
TI - Malignant myeloid transformation with isochromosome 7q in Shwachman-Diamond
syndrome.
AB - Shwachman-Diamond syndrome is an autosomal recessive disorder characterized by
exocrine pancreatic dysfunction, bony metaphyseal dysostosis, various degrees of
cytopenia, and a striking tendency to develop myelodysplastic syndrome and acute
myeloblastic leukemia. Isochromosome 7 [i(7q)] is a rare non-random cytogenetic
abnormality of myeloid cells in hematological malignancy. We report two cases of
Shwachman-Diamond syndrome in which patients developed myelodysplastic syndrome
and i(7q), detected by G-banding karyotype analysis and fluorescence in situ
hybridization. Three other children have been previously reported to have
myelodysplastic syndrome in association with i(7q); two of them had Shwachman
Diamond syndrome. Isochromosome 7q may be a fairly specific marker of myeloid
malignant transformation in this syndrome and play a role in its pathogenesis.
PMID- 9766505
TI - Amifostine stimulates formation of multipotent and erythroid bone marrow
progenitors.
AB - Amifostine (WR-2721, Ethyol) is a phosphorylated aminothiol that affords broad
cytoprotection from the myelosuppressive effects of antineoplastics. To further
characterize its hematopoietic activities, we investigated the effects of
amifostine and its dephosphorylated metabolite, WR1065, on the in vitro growth of
human bone marrow progenitors. Preincubation exposure to amifostine or WR1065
stimulated the growth of colony-forming units granulocyte, erythroid, macrophage,
megakaryocyte (CFU-GEMM) and erythroid bursts (BFU-E) from bone marrow
mononuclear cells in a dose-dependent fashion. Over the concentration range
tested (0.1-1000 microM), pretreatment with the aminothiols enhanced formation of
CFU-GEMM up to five-fold and BFU-E nine-fold, compared to a three-fold increase
in myeloid colony recovery. In CD34+ selected cells, preincubation with
amifostine increased formation of CFU-GEMM up to 38-fold and produced macroscopic
colonies, exceeding colony number in cultures initiated with optimal
concentrations of interleukin-1 (IL-1), IL-3, or kit ligand (KL). When compared
with recombinant human cytokines, amifostine enhanced IL-1 and IL-3 induced
colony formation, although its stimulatory effect was less than additive. In
contrast, pretreatment with amifostine antagonized the stimulatory effects of KL,
whereas synergy was observed with concurrent exposure. Ex vivo expansion studies
showed that amifostine alone supported and augmented the production of myeloid
progenitors in secondary cultures. Similarly, under cytokine-deficient
conditions, amifostine promoted cell survival and delayed apoptosis as measured
by nucleosome generation. These data indicate that amifostine is a novel
multipotent hematopoietic stimulant that augments the formation and survival of
bone marrow progenitors.
PMID- 9766507
TI - Epidemiology and ethnic aspects of B cell chronic lymphocytic leukemia in Israel.
AB - Chronic lymphocytic leukemia (CLL) represents 30% of all leukemias in Caucasians.
In East Europe and USA the disease incidence is high while in Asia and Africa CLL
is rare. The present study deals with 302 cases of B cell CLL and related
disorders; 207 patients originating from Europe and America (Ashkenazi Jews) and
95 descendants from Asia, The Mediterranean or Africa (Sephardic Jews). The
patients were recruited during 1975-1996 in a single center covering the Hashfela
region -- a Southern area of Israel with a current population of 430000
inhabitants. Incidence of the disease, clinical pattern, biological parameters,
prognosis and outcome were investigated and compared in both ethnic groups. The
results of this study show a high incidence of CLL in Israel. The mean annual age
adjusted incidence 4.3 per 100000 person-year is among the highest reported
values. Our study confirms previous data on the prevalence of CLL in Ashkenazi
compared to Sephardic Jews. The rise in CLL rate in the reviewed period occurred
in both populations, mainly in the Sephardic group. The relative risk for
Ashkenazies compared to Sephardics decreased from 6.0 in the 1975-1979 period to
2.4 in 1990-1996. A high rate of CLL was found in new immigrants from the former
USSR with 26 cases de novo diagnosed and 11 prevalent cases not included in this
series among approximately 60000 new immigrants in the ara over the last 8 years.
No differences were found in clinical, laboratory and immunological parameters at
the time of diagnosis in the two ethnic groups. The follow-up showed a similar
pattern in the disease evolution. A preliminary study of immunoglobulin heavy
chain rearrangement performed in 14 patients showed no significant differences in
JH hybridization in the early stages of the disease, but more aberrations in
advanced CLL in the Ashkenazi group. Our findings suggest that ethnic origin of
the patients itself does not affect the biological and clinical behavior of this
disease.
PMID- 9766506
TI - Effects of thrombopoietin, interleukin-3 and the kinase inhibitor K-252a on
growth and polyploidization of the megakaryocytic cell line M-07e.
AB - Thrombopoietin (TPO) is a recently cloned growth and differentiation factor
implicated in megakaryocytopoiesis. Here, we show that TPO, interleukin-3 (IL-3)
and, at least in short-term assays, also interferon gamma (IFN gamma) induced
proliferation in acute myeloid leukemia (AML-M7)-derived M-07e cells. The Janus
kinase/signal transducer and activator of transcription (JAK/STAT) pathway was
activated after stimulation with any of the three cytokines. Thus, the TPO
receptor (TPO-R) MPL was tyrosine phosphorylated after a short-term stimulation
with TPO, followed by tyrosine phosphorylation of STAT 3 and STAT 5, but not of
STAT 1. IL-3 and IFN gamma induced phosphorylation of STAT 5 or STAT 1,
respectively, without affecting the other STATs. As STATs are thought to regulate
proliferation by modulating expression of inhibitors of cyclin-dependent kinases
(Cdk), we analyzed p21 and p27 expression after stimulation with TPO or IL-3. In
contrast to the constitutively low p21 expression, p27 mRNA levels were high in
synchronized, cytokine-deprived cells in G0/1 phase. Stimulation with TPO or IL-3
induced a rapid decrease of p27 mRNA. The phosphorylation cycle of the
retinoblastoma protein (Rb) was inversely correlated with the level of p27 mRNA.
Hyperphosphorylation of Rb was detectable 9 h after onset of stimulation,
concomitantly with the decrease of p27 mRNA and shortly before transition of the
cells into S phase. As phosphorylation of Rb is a key event for transition of
cells into S phase, our observations support the notion of p27 being an important
regulator during cytokine-induced proliferation. Whether the JAK/STAT pathway is
directly involved in p27 expression or not, remains to be elucidated. The JAK
inhibitor AG-490 blocked cytokine-induced STAT 5 phosphorylation and
proliferation of M-07e cells in a dose-dependent manner. Although these data
indicate a role for the JAK/STAT pathway in cytokine-induced proliferation, a
direct influence on the p27 mRNA downregulation has to be confirmed. The second
major effect of TPO, polypoidization, could not be observed in M-07e cells. Even
long-term culture with TPO did not induce endomitosis in these cells. However,
polyploidization could be brought about by the kinase inhibitor K-252a. After 3
days of exposure to this reagent, 17% of the originally mononucleated cells
contained two to five nuclei. K-252a-induced polykaryon formation was not
preceded by STAT 5 phosphorylation. Thus, K-252a did not mimic TPO stimulation at
the early steps of the signaling chain. Taken together, our experiments confirm a
role for the JAK/STAT pathway in cytokine-induced proliferation; TPO and IL-3
induce downregulation of the Cdk inhibitor p27, hyperphosphorylation of Rb and
subsequently transition of the cells into S phase; the kinase inhibitor K-252a
induces polyploidization of M-07e cells, but this effect is independent of STAT 5
phosphorylation.
PMID- 9766509
TI - Decreasing antibiotic resistance of Enterobacteriaceae by introducing a new
antibiotic combination therapy for neutropenic fever patients.
AB - Prompt empiric antibiotic therapy is of critical importance for patients with
neutropenic fever. However, a major concern with important clinical consequences
is the emergence of bacterial resistance to antibiotics. After using ceftazidime
with a glycopeptide as initial empiric therapy for neutropenic fever, we were
confronted with a 75% reduced susceptibility rate to ceftazidime of inducible
Enterobacteriaceae collected in 1994. The initial empiric therapy was therefore
replaced in May 1995 by a combination of cefepime with amikacin, with addition of
a glycopeptide after 48 h if necessary. After this change, we observed a
significant decrease in reduced susceptibility of inducible Enterobacteriaceae,
not only to ceftazidime, but also to amikacin, cotrimoxazole and ciprofloxacin.
There was also a decrease in reduced susceptibility of non-inducible
Enterobacteriaceae, such as Klebsiella spp, to ceftazidime. The reduction of
resistance may be related at least in part to the combined use of cefepime
together with an aminoglycoside. This study shows that it is possible to reverse
bacterial resistance by modifying the antibiotic regimen used.
PMID- 9766508
TI - Oral cytarabine ocfosfate in acute myeloid leukemia and non-Hodgkin's lymphoma-
phase I/II studies and pharmacokinetics.
AB - Cytosine arabinoside (AraC) is rapidly inactivated via systemic deamination with
half-lives ranging from 1 h (i.v.) to 4 h (s.c.) -- and cannot be applied orally
due to its hydrophilic properties. These limitations might be overcome by YNK01 -
a lipophilic prodrug of AraC -- that is resistant to deoxycytidine deaminase and
can be applied orally. In the present study the therapeutic activity, side
effects and pharmacokinetics of YNK01 were evaluated in a phase I/II study
including patients with relapsed or refractory acute myeloid leukemia (AML)
(n=23) or low-grade non-Hodgkin's lymphoma (NHL) (n=20). YNK01 was given by 14
day cycles with escalating doses starting with a daily dose of 50 mg/m2
(equivalent to 20 mg/m2 AraC on a molar basis). The maximum tolerated dose was
reached at the 600 mg/m2 dose level with WHO grade 3-4 diarrhoea as the main
toxicity. In the 23 patients with AML two complete remissions, four partial
remissions and three patients with stable disease were observed. In the 23
patients with AML two complete remissions, four partial remissions and three
patients with NHL two cases reached partial remission and six other patients
mainained stable disease. Pharmacokinetic evaluations were performed during 34
treatment cycles in 28 patients. The data suggest that YNK01 was absorbed in the
distal part of the small intestine and taken up into hepatocytes. After hepatic
psi and subsequent beta-oxydation of YNK01 the released AraC (and its deamination
product AraU) appeared in the systemic circulation. Time of maximum concentration
(h), half-life (h) and area under the curve (ng x h/ml, at the 1200 mg dose
level) were as follows (VC variation coefficient) YNK01: 1.0 (0.58), 10.1 (0.43),
12622 (0.65); AraC: 23.2 (0.57), 22.6 (0.36), 3496 (0.76); AraU: 19.2 (0.58) 22.3
(0.33) 15441 (0.66). Of the total dose of YNK01 15.8% was absorbed and
metabolized to AraC and AraU, defining the metabolic bioavailability of this
prodrug. A linear relationship was observed between YNK01 dose and YNK01 AUC and
AraC AUC over the whole dose range tested. AraC was released from hepatocytes
over a prolonged period of time resulting in long lasting plasma levels similar
to a continuous i.v. infusion. After administration of YNK01 at a dosage of 100
150 mg/m2 plasma levels of AraC were comparable to those achieved after low-dose
AraC treatment (20 mg/m2) while at doses of YNK01 of 450-600 mg/m2 concentrations
of standard-dose AraC (100 mg/m2) were obtained. We conclude that YNK01 shows
considerable activity against relapsed and refractory AML and NHL and that its
pharmacokinetic properties offers advantages in comparison to (standard) i.v. or
s.c. AraC in clinical practice.
PMID- 9766510
TI - Structure of Bcl-1 and IgH-CDR3 rearrangements as clonal markers in mantle cell
lymphomas.
AB - Mantle cell lymphoma represent a clinicopathologically distinct entity of
malignant non-Hodgkin's lymphoma (NHL) and are characterized by a specific
chromosomal translocation t(11;14)(q13;q32) involving the cyclin D1 gene also
designated as bcl-1/PRAD1 gene on chromosome 11 and the heavy chain
immunoglobulin joining region on chromosome 14. We have established a PCR method
to amplify t(11;14) junctional sequences in DNA from fresh frozen and paraffin
embedded tissue by bcl-1-specific primers in combination with a consensus
immunoglobulin JH primer. A total of 65 cases histologically classified as mantle
cell lymphoma (MCL) were analyzed for the presence of a t(11;14) translocation
and monoclonal IgH-CDR3 rearrangements. From 26 patients with classical MCL and
three cases with the anaplastic variant of MCL fresh frozen biopsy material was
available for DNA extraction. We detected a bcl-1/JH rearrangement in 12 out of
29 samples (41%). In 36 cases paraffin-embedded lymph node tissue was the only
source of DNA. In this material we found a bcl-1/JH rearrangement in six out of
31 samples with intact DNA (20%). To confirm the specificity of the PCR and to
determine the bcl-1/JH junctional region sequences as clone-specific marker in
individual patients we characterized the junctional DNA sequences by direct PCR
sequencing in 16 cases. Interestingly we found that six bcl-1/JH junctions
harbored DH segments in their N regions indicating that bcl-1/JH rearrangements
can occur in a later stage of B cell ontogeny during which the complete VH to DH
JH joining or VH-replacement takes place. To investigate the suitability of IgH
CDR3 as sensitive molecular marker for those MCL patients in which a t(11;14)
translocation can not easily be amplified, we additionally analysed 60 cases for
the presence of monoclonally rearranged IgH genes by IgH-CDR3-PCR. A monoclonal
IgH-CDR3 PCR product could be identified in 24 out of 29 fresh frozen samples
(79%) whereas only 11 out of 31 samples (36%) with paraffin-derived DNA were
positive. We demonstrate that automated fluorescence detection of monoclonal IgH
CDR3 PCR products allows the rapid and sensitive monitoring of minimal residual
disease also in cases that lack a PCR amplifiable t(11;14) translocation. In
combination with allele-specific primers the procedure may improve current
experimental approaches for detection of occult MCL cells at initial staging and
residual disease during and after therapy.
PMID- 9766511
TI - Comparative genomic hybridization in childhood acute lymphoblastic leukemia.
AB - DNA copy number changes were studied by comparative genomic hybridization (CGH)
on bone marrow samples obtained from 72 patients with childhood acute
lymphoblastic leukemia (ALL) at diagnosis. The patients had been admitted to the
Helsinki University Central Hospital (Finland) between 1982 and 1997. CGH showed
DNA copy number changes in 45 patients (62.5%) with a mean of 4.6 aberrations per
patient (range, 1 to 22). The results of CGH and chromosome banding analysis were
generally concordant, but CGH facilitated specific karyotyping in 34 cases. DNA
copy number gains were more frequent than losses (gains:losses, 6:1). Gains of
DNA sequences affected almost exclusively whole chromosomes and were most
commonly observed in chromosomes 21 (25%), 18 (22.2%), X (19.4%), 10 (19.4%) and
17 (19.4%). The most common partial gain was 1q31-q32 (8.3%). The most common
gains of chromosomes 21, 18, X, 10, 17, 14, 4, 6 and 8 appeared concurrently.
High-level amplifications of small chromosome regions were sporadic, detected
only in two patients (2.8%). Chromosome 21 was involved in both cases. The most
common losses were 9p22-pter (12.5%) and 12p13-pter (11.1%). No statistically
significant association between the CGH findings and the diagnostic white blood
cell count was observed.
PMID- 9766512
TI - A novel single cell PCR assay: detection of human T lymphotropic virus type I DNA
in lymphocytes of patients with adult T cell leukemia.
AB - The abnormal lymphocytes in adult T cell leukemia (ATL) reveal a peculiar
morphology that is characterized by indented or lobulated nuclei. While human T
lymphotropic virus type I (HTLV-I) is thought to be integrated in ATL cells, the
correlation between the nuclear irregularities and HTLV-I infection is obscure.
We have devised a novel single cell polymerase chain reaction (PCR) technique to
examine the integration of HTLV-I provirus genome in cells from two patients with
ATL. To isolate single cells, peripheral blood smears were prepared on thin
polyester slides and stained with May-Grunwald-Giemsa. Morphologically defined
single cells were cut out after light microscopy. The HTLV-I DNA sequences were
detected not only in ATL cells but also in normal-looking lymphocytes. This novel
PCR method may provide a valuable tool for understanding the molecular events
associated with HTLV-I infection at the single cell level.
PMID- 9766513
TI - Apoptosis of leukemia cells induced by valine-deficient medium.
PMID- 9766514
TI - Serum thrombopoietin levels in acute leukemia patients with chemotherapy-induced
cytopenia--inverse correlation between serum levels and platelet counts.
PMID- 9766515
TI - Multilineage dysplasia without increased blasts identifies a poor prognosis
subset of myelodysplastic syndromes.
PMID- 9766516
TI - Expression of two inward rectifier potassium channels is essential for
differentiation of primitive human hematopoietic progenitor cells.
AB - A potassium inward rectifier (K(ir)) current was previously shown by us to be
induced in primitive hematopoietic progenitor cells, stimulated with the
combination of interleukin-3 (IL-3) and stem cell factor (SCF). Biophysical
features of whole cell currents implicated the involvement of more than one K(ir)
channel type. Employing IL-3 + SCF stimulated human cord blood CD34+38- cells, we
isolated and characterized different components of this current. Reverse
transcription-polymerase chain reaction (RT-PCR) subcloning identified the
expression of a strongly rectifying K(ir) channel (K(ir) 4.3) as well as a weakly
rectifying K(ir) channel (K(ir) 1.1) in these cells. Inhibition of the expression
of each of the channels suppressed progenitor cell generation by IL-3 and SCF
stimulated CD34+38- cells in 7-day suspension cultures. The variable expression
of two essential inward rectifying potassium channels early in the course of
hematopoietic progenitor cell differentiation may play a potentially important
role in potassium homeostasis in these cells.
PMID- 9766517
TI - Cloning of murine CDK9/PITALRE and its tissue-specific expression in development.
AB - The cdc2-family of serine/threonine kinases and their binding partners recently
were implicated in developmental roles. We previously cloned a cdc2-related
kinase, cdk9/PITALRE, that is able to phosphorylate the retinoblastoma protein in
vitro. We describe here the cloning and the characterization of the mouse homolog
of cdk9/PITALRE. The murine cDNA is 98% identical with humans and is expressed at
high levels in brain and kidney tissues. The kinase activity and protein
expression of cdk9/PITALRE were highest in terminally differentiated tissues such
as the muscle and brain. In situ immunohistology and immunofluorescence detected
cdk9/PITALRE protein not only within terminally differentiated cells such as
muscle and neuronal cells, but also in proliferating cells. C2C12 and P19 cells
induced to differentiate along muscle and neural lineages peaked in cdk9/PITALRE
kinase activity at the end of differentiation. These results suggest that, among
other roles, cdk9/PITALRE plays a role not unlike cdk5 in the differentiation of
certain cell types.
PMID- 9766518
TI - Transforming growth factor beta blocks cystogenesis by MDCK epithelium in vitro
by enhancing the paracellular flux: implication of collagen V.
AB - Transforming growth factor beta (TGFbeta) determines a nearly complete inhibition
of cystogenesis by MDCK cells grown in collagen I-enriched matrices in vitro. In
order to elucidate the mechanism implicated in this phenomenon, we performed a
series of experiments aimed at discovering a relevant role of extracellular
matrix. TGFbeta (2 ng/ml) played a marked stimulatory effect on the expression of
extracellular matrix by MDCK with a selective effect on collagen V (three to
fourfold increase of protein and mRNA) and in parallel inhibited cystogenesis by
95%. Cotreatment with TGFbeta and anti-collagen V antibodies restored a normal
cystogenesis. In analogy, when MDCK cells were grown in three-dimensional
matrices containing collagen I and minor (10%) amounts of collagen V,
cystogenesis was once again inhibited by 95%. To characterize the molecular
mechanism activated by TGFbeta and collagen V, we looked at the
electrophysiological characteristics of MDCK monolayers and found a drastic fall
of transepithelial electrical resistance (TER) in both conditions. In parallel
with the decrease in TER, TGFbeta and collagen V also induced the leakage of two
high molecular weight tracers, i.e., [3H]-inulin and 150 kD FITC-Dextran,
suggesting a perturbation of the paracellular permeability. Finally, TGFbeta at
the relevant concentration did not stimulate apoptosis in our cellular model, as
judged by propidium iodide staining and by in situ end labeling of DNA fragments.
These observations suggest that TGFbeta inhibits cystogenesis by MDCK cells in
vitro by altering the collagenic composition of the three-dimensional milieu
where MDCK cells grow and form cysts. The molecular mechanism responsible for
inhibition of cystogenesis is the increase of paracellular flux which overcomes
the active transport of solutes and water inside cysts.
PMID- 9766519
TI - Angiotensin II-stimulated collagen gel contraction by heart fibroblasts: role of
the AT1 receptor and tyrosine kinase activity.
AB - The accumulation and organization of extracellular matrix (ECM) components play
critical roles in development, maintenance, and pathogenesis of most organ
systems. These processes are regulated by the precisely orchestrated expression
of ECM components, their receptors, and matrix proteases. The collagen gel
culture system has been extensively used as a model to examine ECM remodeling
similar to that which occurs during development and wound healing. Growth
factors, including transforming growth factor-beta, platelet-derived growth
factor, insulin-like growth factor, and angiotensin II, have been shown to
stimulate collagen gel contraction. The present studies were undertaken to begin
to examine the mechanisms through which angiotensin II stimulates collagen
remodeling and gel contraction. These studies indicate that angiotensin II
stimulates collagen gel contraction by isolated heart fibroblasts in a dose
dependent manner and that this response is inhibited by the AT1 receptor
antagonist Losartan. Furthermore, stimulation of collagen gel contraction by
angiotensin II is also blocked by the src-related tyrosine kinase inhibitors
genistein and herbimycin, indicating that activation of tyrosine kinases plays
critical roles in this process. Stimulation of gel contraction by angiotensin II
also involves the activation of JAK2, a member of the JAK/STAT pathways of
transcriptional activation. Immunoprecipitation of surface-labeled fibroblasts
indicate that cell surface levels of collagen-binding integrins also increase in
response to angiotensin II treatment. Determining the underlying mechanisms
regulating ECM remodeling is essential to understanding the role of ECM
organization in development and disease.
PMID- 9766520
TI - Differential kinetics for induction of interleukin-6 mRNA expression in murine
peritoneal macrophages: evidence for calcium-dependent and independent-signalling
pathways.
AB - It is presently unclear what role elevations in intracellular calcium
concentration ([Ca2+]i) play in the control of monokine secretion, or whether
such alterations underlie the ability of physiologic stimuli to induce production
of these important signalling molecules. To address these issues, we have
performed experiments in murine peritoneal macrophages to determine whether
lipopolysaccharide (LPS) or interferon gamma (IFN-gamma) initiate production of
the proinflammatory monokine interleukin 6 (IL-6) concomitant with elevations in
[Ca2+]i and with kinetics similar to that seen with known Ca2+ mobilizing agents.
Alterations in [Ca2+]i after treatment with LPS, IFN-gamma, platelet activating
factor (PAF), or thapsigargin were measured by fluorimetric methods. These
effects were compared with the ability of each to induce IL-6 mRNA expression as
measured by semiquantitative reverse-transcribed polymerase chain reactions. We
report that neither LPS nor IFN-gamma elicited detectable elevations in [Ca2+]i
but that both up-regulated expression of IL-6 mRNA expression within 60 min. In
contrast, experiments using either thapsigargin or PAF showed rapid and dramatic
elevations in [Ca2+]i with marked increases in IL-6 mRNA expression, as quickly
as 15 min after initial exposure. Elevations in mRNA encoding IL-6 by
thapsigargin and PAF were found to occur in a dose-dependent manner, mirroring
their ability to elicit elevations in [Ca2+]i. These data demonstrate that LPS
and IFN-gamma induce IL-6 message expression by means of Ca2+-independent
signalling pathways. Furthermore, Ca2+-mobilizing agents that evoke monokine
message expression do so far more rapidly than do LPS or IFN-gamma. Taken in
concert, these data are consistent with the hypothesis that multiple signalling
pathways exist by which production of proinflammatory monokines are initiated.
PMID- 9766521
TI - Molecular cloning and tissue-specific expression of Mrad9, a murine orthologue of
the Schizosaccharomyces pombe rad9+ checkpoint control gene.
AB - We have isolated a murine cDNA, Mrad9, that is orthologous to the fission yeast
rad9+ and human HRAD9 genes. Mrad9 encodes a 389 amino acid long, 42,032 Dalton
protein that is 27% identical and 56% similar to Rad9p, and 82% identical and 88%
similar to HRAD9, at the amino acid level. Expression of the Mrad9 cDNA in
Schizosaccharomyces pombe rad9::ura4+ cells restores nearly wild-type levels of
hydroxyurea resistance and early S phase checkpoint control to mutant fission
yeast cell populations. However, UV resistance is only minimally restored, and
mutant cells remain sensitive to gamma radiation. Mrad9 genomic DNA was isolated
from a mouse 129/SvEv library. The Mrad9 gene was local ized to a 15-kbp genomic
DNA fragment, and contains 10 exons separated by 9 introns. Northern blot
analysis indicates that the gene is expressed in many different tissues of the
adult mouse, but the mRNA is most abundant in the heart and present at very low
levels in the liver. These studies demonstrate the existence of a murine
orthologue of the fission yeast rad9+ gene and underscore at least the partial
evolutionary conservation of rad9+-dependent checkpoint control mechanisms.
PMID- 9766522
TI - Ammonia inhibits neural cell adhesion molecule polysialylation in Chinese hamster
ovary and small cell lung cancer cells.
AB - Ammonia is a major concern in biotechnology because it often limits recombinant
protein production by animal cells. Conditions, such as ammonia accumulation, in
large-scale production systems can parallel those that develop within fast
growing solid tumors such as small cell lung cancer (SCLC). Ammonia's specific
inhibition of the sialylation of secreted glycoproteins is well documented, but
it is not known how ammonia affects membrane-bound proteins, nor what role it may
have on important glycosylation determinants in cancer. We therefore examined the
effects of NH4Cl on polysialic acid (PolySia) in the neural cell adhesion
molecule (NCAM). By using flow cytometry combined with two NCAM antibodies, one
specific for the peptide backbone and another that recognizes PolySia chains, we
show that ammonia causes rapid, dose-dependent, and reversible inhibition of NCAM
polysialylation in Chinese hamster ovary (CHO) and SCLC NCI-N417 cells. The
decrease in PolySia was accompanied by a small increase in NCAM, suggesting that
the changes were specific to the oligosaccharide. Inhibition by ammonia was
greater for CHO cells, with PolySia cell surface content decreasing to 10% of
control after a 4-day culture with 10 mM NH4Cl, while N417 cell PolySia was
reduced by only 35%. Ammonia caused a 60% decrease in the CHO cell yield from
glucose, while N417 cells were barely affected, suggesting that increased
resistance to ammonia by N41 7 cells is a global rather than glycosylation
specific phenomenon. The data presented show that the tumor microenvironment may
be an important factor in the regulation of PolySia expression.
PMID- 9766523
TI - Gamma-irradiation-induced cell cycle arrest and cell death in a human
submandibular gland cell line: effect of E2F1 expression.
AB - This study examined the effect of gamma-irradiation (5 and 10 Gy) on the human
submandibular cell line (HSG). Radiation treatment (5 Gy and 10 Gy) induced a
dose-dependent decrease in cell proliferation, with a G2/M arrest of the cell
cycle, and an increase in cell death (cells with <2n DNA increased from 7% in
control cells to 34% and 40% in 5 and 10 Gy irradiated cells, respectively).
[Ca2+]i measurements demonstrated that the status of internal Ca2+ stores, and
muscarinic receptor-mediated Ca2+ mobilization, in irradiated cells was
comparable to that in non-irradiated cells. These data suggest that 1) irradiated
HSG cells maintain normal physiology and 2) internal Ca2+ store depletion does
not account for the decreased cell proliferation. To manipulate the radiation
induced cell cycle arrest, we examined the effect of the transcription factor
E2F1, which has been shown to induce cell cycle progression in HSG cells
(Lillibridge and O'Connell, 1997, J. Cell. Physiol., 1 72:343-350). The ability
of irradiated HSG cells to express and appropriately route proteins was
demonstrated by using adenovirus-mediated expression of beta-galactosidase,
alpha1-antitrypsin, and aquaporin-1. Infection of HSG cells with an adenoviral
vector encoding E2F1, either 12 h before or immediately following irradiation,
but not post-irradiation, induced maintenance of cells in the S phase of the cell
cycle, reduced the number of cells arrested at G2/M, and decreased the rate of
appearance of cells with <2n DNA. While the mechanism of irradiation-induced cell
death has not yet been confirmed, these data suggest that expression of the E2F1
gene product in HSG cells can be a useful strategy to manipulate cell cycle
events and reduce the initial loss of cells due to radiation.
PMID- 9766524
TI - Cellular characterization and successful transfection of serially subcultured
normal human esophageal keratinocytes.
AB - BACKGROUND: In vitro cell culture models can provide unique insights into
squamous epithelial proliferation, differentiation, and neoplastic
transformation. Cultures of human esophageal keratinocytes could be advantageous
for the study of these processes. METHODS: Normal human esophageal keratinocytes
were cultivated on 3T3 fibroblast feeder layers in vitro and expanded through
four serial subcultivations. Confluent tertiary cultures were analyzed by
morphological and immunohistochemical techniques to define their basic
properties. The ability to transiently transfect cultured esophageal epithelium
was tested using a Rous sarcoma virus-luciferase reporter gene by the calcium
phosphate and lipofection methods. RESULTS: Postconfluent cultures displayed a
predominantly basal cell phenotype with limited stratification, widespread
expression of keratins 5 and 14, and production of attachment specialization
proteins such as alpha6beta4 integrin and collagen VII. Terminal differentiation
markers (involucrin and transglutaminase) were prematurely expressed. The cells
expressed growth factors important in proliferation and differentiation, such as
transforming growth factor-beta and interleukin-1beta. Tertiary cultures were
successfully transiently transfected with a Rous sarcoma virus-luciferase
reporter gene construct. CONCLUSION: Normal human esophageal cells can be
serially passaged through extended numbers of cell generations and transfected by
standard methods. This in vitro system may be useful in the study of fundamental
cellular processes governing proliferation and differentiation in the esophageal
epithelium.
PMID- 9766525
TI - Down-regulation of epidermal growth factor receptor-signaling pathway by binding
of GRP78/BiP to the receptor under glucose-starved stress conditions.
AB - GRP78/BiP, a molecular chaperone in the endoplasmic reticulum, is induced under
such adverse conditions for cell survival as glucose starvation. Induction of
GRP78 has been shown to coincide with G1 cell cycle arrest, which is an important
cellular defense system. In this study, we investigated involvement of GRP78 in
the mechanism of growth arrest by using human epidermoid carcinoma A431 cells.
Under a chemical stress condition with 2-deoxyglucose, GRP78 was induced 3-4
fold. In the stressed cells, an underglycosylated form of epidermal growth factor
receptor (EGFR) was produced and the mature form was decreased. We found that the
molecular chaperone GRP78 in the endoplasmic reticulum formed a stable complex
with the underglycosylated EGFR but did not with the mature form. This complex
formation occurred specifically under the stress conditions, and the complex was
dissociated upon removal of the stress. Treatment of the GRP78-underglycosylated
EGFR complex with ATP resulted in a release of the underglycosylated EGFR from
GRP78, indicating that the complex could be formed through the chaperone function
of GRP78. In accordance with the complex formation with endoplasmic reticulum
resident GRP78, the underglycosylated EGFR could not be translocated to the cell
surface. As a result, EGF could not induce expression of cyclin D3, a G1 cyclin,
in the stressed cells, whereas it did in non-stressed cells. These results
indicated that, in the stressed cells, GRP78 participated in down-regulation of
EGF-signaling pathway by forming a stable complex with EGFR and inhibiting EGFR
translocation to the cell surface.
PMID- 9766526
TI - Influence of calcium on proliferation and phenotype alteration of cardiomyocyte
in vitro.
AB - An accelerated weight gain is noted in the heart of Ca-deficient, hypertensive
chick embryos maintained in a shell-less culture in vitro. We previously observed
that the Ca handling property of cardiomyocytes isolated from the shell-less
embryo is altered, i.e., faster Ca uptake, suggesting a requirement for adequate
Ca supply and/or proper Ca handling in embryonic cardiac development. In this
study, we have examined the function of Ca on cardiomyocytes by analyzing the
effects of 1) various Ca concentration in the culture medium (NCa, 1.8 mmol/ L;
HCa, 2.8 mmol/L; LCa, 0.9 mmol/L), and 2) various modulators of Ca handling on
cell proliferation and phenotype regulation in chick embryonic cardiomyocytes.
The analytical parameters included cell number, DNA content, expression of cell
cycle-specific and cardiomyocyte-specific proteins, and creatine phosphokinase
(CPK) and lactate dehydrogenase (LDH) enzyme activities. Cell number and total
DNA were significantly larger (P < 0.01) in LCa cultures compared with those in
NCa. The level of LDH was elevated (P < 0.01), but that of CPK was lowered in
LCa. Expression of the G1-S-specific protein PCNA was raised, but that of the
contractile proteins myosin and tropomyosin was substantially suppressed in LCa;
in HCa, the cells did not proliferate as well, whereas the level of contractile
proteins was higher. Thapsigargin, a sarcoplasmic reticulum (SR)-specific, Ca
ATPase inhibitor, simulated the effects of LCa by enhancing cell proliferation
and lowering the expression of tropomyosin. These results suggest that culturing
in low Ca concentration and inhibition of SR Ca pumping enhance myocardial cell
proliferation and suppress sarcomeric protein expression, perhaps by inducing
cellular de-differentiation. The in vitro effects of medium Ca concentration and
Ca handling modulators on cardiomyocytes also suggest that the in vivo
cardiomegaly of the SL embryos is a direct result of Ca-deficiency, and that Ca
is important in the phenotype regulation of cardiomyocytes.
PMID- 9766527
TI - Expression of the NG2 proteoglycan enhances the growth and metastatic properties
of melanoma cells.
AB - The human homologue of NG2, the human melanoma proteoglycan (HMP), is expressed
on most human melanomas. To investigate the role of this proteoglycan in melanoma
progression, we have attempted to identify functionally important molecular
ligands for NG2. Immunohistochemical analysis of cell lines that endogenously
express NG2/HMP suggests that NG2/HMP associates with CD44 and alpha4beta1
integrin, two molecules previously implicated in melanoma progression.
Transfection of rat NG2 into the NG2-negative B16 mouse melanoma cell line also
resulted in a highly colocalized pattern of expression between the transfected
rat NG2 and the endogenously expressed mouse CD44 and alpha4beta1 integrin
molecules. In functional assays, expression of NG2 decreased the adhesion of B16
melanoma cells to CD44 monoclonal antibodies, hyaluronic acid, the C-terminal 40
kDa fibronectin fragment, and the CS1 fibronectin peptide, suggesting that NG2
may negatively modulate CD44- and alpha4beta1-mediated binding events. Expression
of NG2 increased the proliferation of melanoma cells in culture and increased
tumorigenicity in vivo. Moreover, NG2 expression led to increased lung metastasis
of B16F1 and B16F10 melanoma cells in experimental metastasis studies. Together,
these studies demonstrate that NG2 is capable of modulating the adhesion,
proliferation, and metastatic potential of melanoma cells.
PMID- 9766528
TI - Induction of interleukin-8 by ozone is mediated by tyrosine kinase and protein
kinase A, but not by protein kinase C.
AB - Ozone is one of the most common air pollutants humans routinely inhale. We have
previously shown that in vitro ozone exposure induces the DNA-binding activities
of NF-kappaB and NF-IL6 as well as the expression of interleukin 8 in respiratory
epithelial cells. In this study, we investigated intracellular signaling steps
mediating ozone-induced inflammatory mediator release. A549 cells, a type II like
alveolar epithelial cell line, were exposed in vitro to air or 0.1 ppm of ozone
in the presence of several kinase inhibitors. Exposure to ozone increased
interleukin 8 expression and transcription factor activities in a protein
tyrosine kinase (PTK)-dependent and protein kinase A (PKA)-dependent, yet protein
kinase C (PKC)-independent, manner. Furthermore, ozone-induced PTK and PKA
activities but failed to induce PKC activity. In addition, our results suggest
that ozone-induced PTK and PKA activities were reactive oxygen intermediate
dependent and occurred in parallel, because specific inhibitors for PTK and PKA
failed to block the other kinase's activity. These results indicate that PTK and
PKA activities are early events in the signal transduction cascade mediating the
ozone-induced activation of NF-kappaB and NF-IL6 as well as the release of
interleukin 8.
PMID- 9766529
TI - Involvement of reactive oxygen species and caspase 3 activation in arsenite
induced apoptosis.
AB - Recent studies indicate that arsenic may generate reactive oxygen species to
exert its toxicity. However, the mechanism is still unclear. In this study, we
demonstrate that arsenite is able to induce apoptosis in a concentration- and
time-dependent manner; however, arsenate is unable to do so. An increase of
intracellular peroxide levels was accompanied with arsenite-induced apoptosis, as
demonstrated by flow cytometry using DCFH-DA. N-Acetyl-L-cysteine (a thiol
containing antioxidant), diphenylene iodonium (an inhibitor of NADPH oxidase),
4,5-dihydro-1,3-benzene disulfonic acid (a selective scavenger of O2-), and
catalase significantly inhibit arsenite-induced apoptosis and intracellular
fluorescence intensity. In contrast, allopurinol (an inhibitor of xanthine
oxidase), indomethacin (an inhibitor of cyclooxygenase), superoxide dismutase, or
PDTC had no effect on arsenite-induced cell death. Activation of CPP32 activity,
PARP (a DNA repair enzyme) degradation, and release of cytochrome c from
mitochondria to the cytosol are involved in arsenite-induced apoptosis, and Bcl-2
antagonize arsenite-induced apoptosis by a mechanism that interferes in the
activity of CPP32. These results lead to a working hypothesis that arsenite
induced apoptosis is triggered by the generation of hydrogen peroxide through
activation of flavoprotein-dependent superoxide-producing enzymes (such as NADPH
oxidase), and hydrogen peroxide might play a role as a mediator to induce
apoptosis through release of cytochrome c to cytosol, activation of CPP32
protease, and PARP degradation.
PMID- 9766530
TI - Neurofibrosarcoma-derived Schwann cells overexpress platelet-derived growth
factor (PDGF) receptors and are induced to proliferate by PDGF BB.
AB - Neurofibromatosis type 1 (NF1) is characterized by the formation of
neurofibromas, benign tumors of the peripheral nerve consisting essentially of
Schwann cells, which can sometimes turn malignant to form neurofibrosarcomas. The
mechanism of progression toward a malignant phenotype remains largely unknown. In
this report, we show that platelet-derived growth factor (PDGF) BB, and to a
lesser extent fibroblast growth factor 2, are mitogenic for two neurofibrosarcoma
derived Schwann cell lines, but not for a Schwann cell line derived from a
schwannoma (from a non-NF1 patient) or for transformed rat Schwann cells. Levels
of expression of both PDGF receptor alpha and beta are significantly increased in
the two neurofibrosarcoma-derived cell lines compared to the non-NF1 Schwann cell
lines. The level of tyrosyl-phosphorylated PDGF receptor beta is strongly
increased upon stimulation by PDGF BB. In comparison, only modest levels of
tyrosyl-phosphorylated PDGF receptor alpha are observed, upon stimulation by PDGF
AA or PDGF BB. Accordingly, PDGF AA is only a weak mitogen for the
neurofibrosarcoma-derived cells by comparison to PDGF BB. These results indicate
that the mitogenic effect of PDGF BB for the neurofibrosarcoma-derived Schwann
cell lines is primarily transduced by PDGF receptor beta. Neu differentiation
factor beta, a potent mitogen for normal Schwann cells, was unable to stimulate
proliferation of the transformed Schwann cell lines, due to a dramatic down
regulation of the erbB3 receptor. Therefore, aberrant expression of growth factor
receptors by Schwann cells, such as the PDGF receptors, could represent an
important step in the process leading to Schwann cell hyperplasia in NF1.
PMID- 9766531
TI - Growth plate chondrocytes store latent transforming growth factor (TGF)-beta 1 in
their matrix through latent TGF-beta 1 binding protein-1.
AB - Osteoblasts produce a 100 kDa soluble form of latent transforming growth factor
beta (TGF-beta) as well as a 290 kDa form containing latent TGF-beta binding
protein-1 (LTBP1), which targets the latent complex to the matrix for storage.
The nature of the soluble and stored forms of latent TGF-beta in chondrocytes,
however, is not known. In the present study, resting zone and growth zone
chondrocytes from rat costochondral cartilage were cultured to fourth passage and
then examined for the presence of mRNA coding for LTBP1 protein. In addition, the
matrix and media were examined for LTBP1 protein and latent TGF-beta. Northern
blots, RT-PCR, and in situ hybridization showed that growth zone cells expressed
higher levels of LTBP1 mRNA in vitro than resting zone cells. Immunohistochemical
staining for LTBP1 revealed fine fibrillar structures around the cells and in the
cell matrix. When the extracellular matrix of these cultures was digested with
plasmin, LTBP1 was released, as determined by immunoprecipitation. Both active
and latent TGF-beta1 were found in these digests by TGF-beta1 ELISA and Western
blotting. Immunoprecipitation demonstrated that the cells also secrete LTBP1
which is not associated with latent TGF-beta, in addition to LTBP1 that is
associated with the 100 kDa latent TGF-beta complex. These studies show for the
first time that latent TGF-beta is present in the matrix of costochondral
chondrocytes and that LTBP1 is responsible for storage of this complex in the
matrix. The data suggest that chondrocytes are able to regulate both the temporal
and spatial activation of latent TGF-beta, even at sites distant from the cell,
in a relatively avascular environment.
PMID- 9766533
TI - Comparison of bax, waf1, and IMP dehydrogenase regulation in response to wild
type p53 expression under normal growth conditions.
AB - Recently, we demonstrated that downregulation of inosine-5'-monophosphate
dehydrogenase (IMPD; IMP:NAD oxidoreductase, EC 1.2.1.14), the rate-limiting
enzyme for guanine nucleotide biosynthesis, is required for p53-dependent growth
suppression. These studies were performed with cell lines derived from immortal,
nontumorigenic fibroblasts that express wild-type p53 conditionally by virtue of
a metal-responsive promoter. Here, the p53-dependent properties of the original
"p53-inducible" fibroblasts are presented in detail and compared to related
properties of epithelial cells that also express wild-type p53 conditionally, but
by virtue of a temperature-responsive promoter. Both types of p53-inducible cells
were designed to approximate normal physiologic relationships between the host
cell and the regulated p53 protein. Together, they were used to investigate
expression relationships between IMPD and other p53-responsive genes proposed as
mediators of p53-dependent growth suppression. In both types of cells, IMPD
activity, protein, and mRNA were consistently coordinately reduced in response to
p53 expression. In contrast, mRNAs for waf1, bax, and mdm2 showed disparate
patterns of expression, being induced in one conditional cell type, but not the
other. This distinction in regulation pattern suggests that under normal growth
conditions, unlike IMPD downregulation, bax and waf1 induction is not a rate
determining event for p53-dependent growth suppression.
PMID- 9766534
TI - Are there risks in continuing education?
PMID- 9766532
TI - Intracellular signaling of osteogenic protein-1 through Smad5 activation.
AB - Smad proteins play pivotal roles in the intracellular signaling of the
multifunctional transforming growth factor-beta (TGF-beta) family members
downstream of serine/threonine kinase type I and type II receptors. Smad2 and
Smad3 are specific mediators of TGF-beta and activin, while Smadl and Smad5 are
involved in bone morphogenetic protein-2 (BMP-2) and BMP-4 signaling. Here we
report that osteogenic protein-1 (OP-1), also termed BMP-7, binds predominantly
to BMPR-IB in the rat osteoprogenitor-like cell line, ROB-C26. Smad1, Smad5, and
Smad8, but not Smad2 and Smad3, were found to stably interact with the kinase
deficient BMPR-IB after it was phosphorylated by the BMPR-II kinase. In ROB-C26
cells, which express Smad2, Smad3, Smad4, and Smad5, OP-1 was found to stimulate
the phosphorylation of Smad5. Whereas transfection of wild-type Smad5 enhanced
the OP-1-induced response, transfection of wild-type Smad2 had no effect on OP-1
signaling. A Smad5-2SA mutant, in which the two most carboxy-terminal serine
residues were mutated to alanine residues, was found to act as a dominant
negative inhibitor of OP-1-induced responses upon its transfection into various
cell types, including ROB-C26 cells, in contrast to ectopic expression of a Smad2
2SA mutant which was without effect. Smad5, therefore, is a key component in the
intracellular signaling of OP-1.
PMID- 9766535
TI - Comparison of propofol and methohexital continuous infusion techniques for
conscious sedation.
AB - PURPOSE: Methohexital and propofol have been shown to be effective agents for
continuous intravenous infusion to produce conscious sedation during oral
surgical procedures. The current study was conducted to compare these techniques
for intraoperative cardiopulmonary stability, patient cooperation, amnesia,
comfort, recovery time, and postoperative nausea and vomiting. METHODS: Seventy
ASA Class I or Class II patients between the ages of 18 and 40 years, scheduled
for surgical extraction of impacted third molars, were entered into the study.
Thirty-five patients were assigned to group A (methohexital) and 35 were assigned
to group B (propofol). Intravenous sedation was accomplished using premedication
with 1.5 microg/kg of fentanyl and 0.05 mg/kg of midazolam followed by the
continuous infusion of methohexital or propofol at a rate of 50 microg/kg/min.
The infusion was then titrated to 100 microg/kg/min to accomplish a level of
sedation in which the eyes were closed and the patients were responsive to verbal
commands. Subjects were monitored for variability of heart rate, blood pressure,
oxygen saturation, amnesia, comfort, cooperation, nausea and vomiting, and
recovery time based on cognitive, perceptual, and psychomotor tests. RESULTS:
There was no statistical difference between the two medication groups except for
heart rate, which was found to increase by 11 beats/min for group A and only
three beats/min in group B. CONCLUSION: A continuous infusion technique using
either methohexital or propofol (50 to 100 microg/kg/min) was found to be safe
and effective, with no clinically significant differences in cooperation,
cardiopulmonary stability, recovery time, amnesia, comfort, and the incidence of
nausea or vomiting. However, the cost-effectiveness of methohexital is superior
to that of propofol.
PMID- 9766536
TI - The use of ultrasonography as a diagnostic tool for superficial fascial space
infections.
AB - PURPOSE: This study examined the value of ultrasonography as a diagnostic tool in
the treatment of superficial acute odontogenic fascial space infections. PATIENTS
AND METHODS: The study group consisted of 50 patients in whom both radiographic
and sonographic examinations, as well as a needle aspiration, were performed.
RESULTS: Purulent fluid was aspirated in 22 of the 50 patients. Six patients
diagnosed as suffering from cellulitis had a repeated ultrasonography scan. In
four, abscess formation was diagnosed on the third day. CONCLUSIONS:
Ultrasonography is an effective diagnostic tool to confirm abscess formation in
the superficial fascial spaces and is highly predictable in detecting the stage
of infection.
PMID- 9766537
TI - Surgical management of temporomandibular joint ankylosis type III by retaining
the displaced condyle and disc.
AB - PURPOSE: This article proposes a hypothesis regarding the value of saving the
fractured condyle and disc in their displaced position in ankylosis type III for
optimal temporomandibular joint (TMJ) function and growth, and describes four
cases treated in this manner. PATIENTS AND METHODS: Four patients (three females
and one male, 9 to 48 years old) with TMJ ankylosis type III of 3 to 8 years'
duration, a maximal mouth opening of 15 to 19 mm, and severely limited lateral
and protrusive movements were treated. The ankylosed sites were resected, leaving
the displaced condyle and disc in their medial position. RESULTS: Fifteen to 60
months after surgery, the patients had a maximal mouth opening of 44 to 50 mm, as
well as better contralateral and protrusive movements. In addition, two young
patients (9 and 11 years old) showed an improved facial symmetry. CONCLUSIONS:
Treatment of patients with type III TMJ ankylosis should involve retention rather
than removal of the displaced condyle and disc. The condyle and disc are left
untouched in their precarious medial position so as to provide normal function
and growth.
PMID- 9766538
TI - Contralateral coronoid process bone grafts for orbital floor reconstruction: an
anatomic and clinical study.
AB - PURPOSE: This study compares the contour of the coronoid process with the orbital
floor using skulls and shows the use of this bone as a graft for orbital floor
reconstruction. METHODS: Measurements and contour evaluations of the orbital
floor and the contralateral mandibular coronoid process (12 right orbital floors
with the lateral surface of the left coronoid process and 12 left orbital floors
with the lateral surface of the right coronoid processes) were made in 24 dried
adult human skulls (age, race, gender unknown) to assess the feasibility of using
the mandibular coronoid process for orbital floor reconstruction. Applying the
findings of this study, eight patients who had sustained either an isolated
orbital floor blowout fracture (n = 2) or orbital floor compromise with an
associated zygomatic bone fracture (n = 6) were treated by using their
contralateral coronoid process for repair of the orbital floor. RESULTS: Anatomic
Study: Measurements and contour comparisons of the right orbital floor with the
left lateral cortex of the coronoid process in 12 skulls and the left orbital
floor with the right lateral cortex of the coronoid process in the another 12
skulls showed a close match in contour and demension. CLINICAL STUDY: Although
minimal trimming of the peripheral bony margins and medial coronoid cortical
plate was needed, none of the grafts required recontouring of their lateral
cortical surface in the eight patients. Postoperative radiographic studies showed
a correct anatomic contour of the orbital floor. A 1-year follow-up of each
patient showed no occurrence of diplopia, enophthalmia, muscle entrapment, or
infection. All eight patients had transient (1 to 2 weeks) trismus. CONCLUSION:
Based on the anatomic studies and clinical results, the coronoid process makes an
excellent donor graft site for reconstruction of orbital floor deformities.
PMID- 9766539
TI - Blindness associated with midfacial fractures.
AB - PURPOSE: This study assessed the frequency of blindness associated with midfacial
fractures and correlated this with the fracture pattern. PATIENTS AND METHODS: A
retrospective analysis of 49 patients admitted with midfacial fractures from
January 1995 to March 1997 was performed to determine the presence of
posttraumatic blindness. The medical and radiological records of the patients
with blindness were reviewed for age and sex, cause of the injury, type of facial
fracture, type of ocular trauma, and probable cause of the blindness. RESULTS:
Ten of the 49 patients lost vision in one eye (20% of all midfacial fractures and
22% of midface fractures involving the orbit). The possibility of blindness
associated with facial fractures was directly related to the severity of injury.
Road traffic accidents were the most common cause. Blindness was attributable to
traumatic optic nerve injury in seven cases and a ruptured globe in three cases.
CONCLUSIONS: The high frequency of blindness associated with midfacial fractures
in this series was attributable to the predominance of road traffic accidents as
the major cause and absence of an obligatory seat belt law. Early diagnosis of
the exact nature of the ophthalmic injury and treatment are important, and
involvement of the ophthalmologist is mandatory.
PMID- 9766540
TI - Changing trends in the treatment of zygomaticomaxillary complex fractures: a 12
year evaluation of methods used.
AB - PURPOSE: The efficacy of the current methods for the treatment of fractures of
the zygomaticomaxillary complex was evaluated. PATIENTS AND METHODS: One thousand
two hundred seventy-seven patients with fracture of the zygomaticomaxillary
complex and 196 patients with fractures of the zygomatic arch that were admitted
between 1984 and 1995 were evaluated. One thousand one hundred fifty surgical
procedures were performed, and in 401 cases, no operative treatment was
considered necessary. The Gillie's approach was used in 514 cases, intraosseous
wiring in 89 cases, bone plate osteosynthesis in 322 cases, Roger-Anderson pins
in 180 cases, antral packing in 17 cases, and elevation with a hook in 28 cases.
RESULTS: The best results were achieved with the use of semirigid fixation with
miniplates applied at one or more sites of the fractured complex, occasionally
used in combination with other methods such as Roger-Anderson pins. CONCLUSIONS:
Semirigid fixation with miniplates offers the most reliable method available
today for the treatment of zygomatico-orbital complex fractures and has
practically replaced every other method in our institution. The increased cost
and occasionally the necessity to remove the hardware are the main disadvantages
of the method.
PMID- 9766541
TI - A cadaveric study of maxillary sinus size as an aid in bone grafting of the
maxillary sinus floor.
AB - PURPOSE: This study measured maxillary sinus volume as an aid in determining
graft bone volume before grafting of the maxillary sinus floor. MATERIALS AND
METHODS: Maxillary sinus size was measured in 32 cadavers (59 sinuses) using
casts of the maxillary sinus made using dental impression material. RESULTS:
Anteroposterior length, height, width, and volume of the maxillary sinus (mean+/
SD) were 30.1+/-5.65 mm, 34.6+/-7.71 mm, 25.4+/-5.71 mm, and 11.3+/-4.60 cm3,
respectively. When the sinus-lift procedure was simulated, inferior sinus volumes
(mean +/- SD) were 3.51+/-1.23 cm3 for a 15-mm lift and 5.66+/-1.71 cm3 for a 20
mm lift. CONCLUSIONS: In bone grafting of the maxillary sinus floor, taking into
consideration individual differences in maxillary sinus volume and resorption of
the grafted bone, 4.74 cm3 or more of the graft is required for a 15-mm lift, and
7.37 cm3 or more is required for a 20-mm lift.
PMID- 9766542
TI - Anatomic and mechanical properties of the lateral disc attachment of the
temporomandibular joint.
AB - PURPOSE: This study measured the strength to failure of the human
temporomandibular joint (TMJ) lateral disc attachment (LDA) using a tension
compression machine. These data were correlated with the LDA location and its
morphologic aspects, the age and sex of the subjects, and the amount of the
lateral pterygoid muscle (LPM) inserted in the disc. METHODS: Forty-two TMJs
without any obvious internal damage were carefully dissected to preserve the LDA.
The width of insertion of the lateral pterygoid muscle fibers in the anterior
band, as well as the width of the disc, were measured. The tension test was
performed until the complete failure of the sample using a screw machine.
RESULTS: Two types of LDA were recognized. In LDA 1, the anterior and posterior
bands lateral disc junction were directly inserted on the lateral pole, whereas
in LDA 2 this lateral junction was attached behind and below the pole through a
sheet of fibrous tissue. The breaking points for LDA 1 (55.8 N) and LDA 2 (28.8
N) were significantly different (P = .03). No correlation was found between the
amount of LPM discal fibers insertion, sex, age, or the LDA breaking strength
point. CONCLUSION: The LDA 2 insertion strongly suggests that the lateral joint
ligament together with the capsule may act as a substitute for the original disc
attachment to the lateral pole of the condyle.
PMID- 9766543
TI - Histologic changes in the sinus membrane after maxillary sinus augmentation in
goats.
AB - PURPOSE: Previous studies have reported on the morphologic aspects of bone
regeneration after maxillary sinus grafting. However, no previous studies have
examinated the morphology of the maxillary sinus mucosa after grafting. The
purpose of this study was to evaluate the histologic changes in the lining
membrane after sinus augmentation. MATERIALS AND METHODS: A unilateral osteotomy
of the lateral maxillary wall, medial displacement of the bony segments, and
elevation of the sinus mucosa were performed in 12 goats. An autogenous bone
graft combined with coralline particles was placed on the floor of the sinus in
three animals, and coralline particles alone were placed in three other goats.
Six goats were not grafted and were used as controls. Samples were harvested at
2.5, 4.5, and 6.5 months. The maxillary sinus mucosa was examined using light
microscopy and scanning and transmission electronic microscopy. RESULTS: The
coralline particles were surrounded by fibrous connective tissue when used alone.
The addition of iliac crest bone to the coralline particles stimulated bone
formation. After the sinus augmentation, the mucosal lining showed a lack of
glands in the lamina propria, and the epithelium showed an increase in goblet
cells. CONCLUSION: It was concluded that the sinus mucosa undergoes physiologic
adaptations and remains healthy and free of chronic sinusitis after maxillary
sinus grafting.
PMID- 9766544
TI - Chronic, progressive limitation of mouth opening.
PMID- 9766545
TI - Ameloblastoma of the mandible involving an autogenous bone graft.
PMID- 9766546
TI - Mandibular malignant schwannoma with multiple spinal metastases: a case report
and a review of the literature.
PMID- 9766547
TI - An unusual tumor of the mandible with features of unicystic ameloblastoma and
ameloblastic fibroma.
PMID- 9766548
TI - Bilateral oral commissurotomy using buccal mucosa flaps for management of
microstomia: report of a case.
PMID- 9766549
TI - Tongue necrosis in a patient with temporal arteritis.
PMID- 9766550
TI - Intramuscular myxoma of the temporalis muscle.
PMID- 9766551
TI - Osteopetrosis: a review of the literature and report of a case complicated by
osteomyelitis of the mandible.
PMID- 9766552
TI - Preservation of the inferior alveolar nerve in the surgical approach to cancer of
the posterior oral cavity.
PMID- 9766553
TI - A technique for improving the handling of particulate cancellous bone and marrow
grafts using platelet gel.
PMID- 9766554
TI - The use of dogs for experimentation.
PMID- 9766555
TI - The use of dogs for experimentation.
PMID- 9766556
TI - Risks of brain tumour following treatment for cancer in childhood: modification
by genetic factors, radiotherapy and chemotherapy.
AB - A cohort of 4,400 persons treated for various cancers of childhood in France and
the UK was followed up over an extended period to assess risks of subsequent
brain tumour in relation to the radiotherapy and chemotherapy that the children
received for their first cancer. Elevated risks of subsequent brain tumours were
associated with first central nervous system (CNS) tumour (two-sided p = 0.0002)
and neurofibromatosis (two-sided p = 0.001). There was also elevated brain tumour
risk (two-sided p = 0.003) associated with ionising radiation exposure, the risk
being concentrated among benign and unspecified brain tumours. The radiation
related risk of benign and unspecified brain tumours was significantly higher
than that of malignant brain tumours (two-sided p< or =0.05); there was no
significant change of malignant brain tumour risk with ionising radiation dose
(two-sided p > 0.2). In general, there were no strong associations between
alkylating agent dose and brain tumour risk. The only significant association
between brain tumour risk and alkylating agent dose was in relation to compounds
used (bleomycin, chloraminophen) that are thought not to deliver substantial
doses to the brain; the statistical significance of the trend with dose depended
on a single case, and thus must be considered a weak result.
PMID- 9766557
TI - Body site distribution of cutaneous malignant melanoma in relationship to
patterns of sun exposure.
AB - A study of all newly incident melanoma patients in British Columbia in 1991-1992
was undertaken to test the hypothesis raised by an earlier study, which showed
that in younger patients the incidence rate of melanoma per unit area of skin was
higher on intermittently exposed skin areas than on continuously exposed areas.
Using 1,033 patients and a more detailed body site categorisation than was
previously possible, our results confirmed that in both men and women under age
50 the highest melanoma density was on the back. At ages over 50, the greatest
density occurred on fully exposed sites, such as the face, though the dorsum of
the hand and forearm, likely also to have high exposure, show very low melanoma
densities. Differences between males and females correlate well with differences
in likely exposure patterns. These results were seen for all invasive cutaneous
melanomas combined; the patterns were similar for subtypes and for both invasive
and in situ melanoma, with the exception of lentigo maligna melanoma (LMM), which
occurs almost exclusively on the face, even at younger ages. Comparison with the
earlier study (1976-1979) shows that the age-standardised rates for melanoma
excluding LMM have increased by 60%, with the greatest proportional increase
being at younger ages; in the recent data, the age-standardised rate for
intermittently exposed sites exceeds that for usually exposed sites. Our results
confirm that intermittent sun exposure has a greater potential for producing
melanoma than continuous exposure at ages below about 50, though at older ages
melanoma is more common on body sites with continuous sun exposure.
PMID- 9766558
TI - HPV 16 and cigarette smoking as risk factors for high-grade cervical intra
epithelial neoplasia.
AB - Although genital human papillomavirus (HPV) infection is well established as the
etiologic agent for cervical intraepithelial neoplasia (CIN), little is known
about the cofactors involved in the development of high-grade lesions or the
progression of low-grade to high-grade lesions. In our study of HPV-infected
women with CIN (163 CIN I, 51 CIN II and 44 CIN III), women with CIN II or III
were compared with those with CIN I for risk factors associated with high-grade
lesions. After controlling for age, education, ethnicity and frequency of Pap
smear screening, infection with HPV 16, but not high viral load or infection with
multiple types, was associated with high-grade lesions (OR for CIN II = 11.96, OR
for CIN III = 23.74). Risk of CIN III, but not CIN II, increased with number of
cigarettes smoked per day (ORs = 1.49 and 3.35 for < or = 10 and > 10 cigarettes
per day, respectively) and decreased with frequency of condom use during sex (ORs
= 0.60 and 0.32 for women who used condoms occasionally/sometimes and most/all of
the time, respectively). There were no associations between high-grade lesions
and plasma levels of micronutrients (retinol, beta-carotene, alpha-tocopherol and
reduced ascorbic acid). Our results indicate that infection with HPV 16 is
associated with high-grade lesions. Additional cofactors, such as cigarette
smoking, may be required as a carcinogen to advance HPV-infected cells toward
neoplastic progression.
PMID- 9766559
TI - Cancer cells overexpress mRNA of urokinase-type plasminogen activator, its
receptor and inhibitors in human non-small-cell lung cancer tissue: analysis by
Northern blotting and in situ hybridization.
AB - The transcriptional localizations of urokinase-type plasminogen activator (uPA),
its receptor (uPAR) and its inhibitors (PAI-1 and PAI-2), which are possibly
involved in cancer metastasis, have not been determined in human lung cancer. To
identify their regulation in primary non-small-cell lung cancer, we assayed mRNA
levels by Northern blot analysis in 25 cases and determined the localizations of
mRNA by in situ hybridization in 10 cases. The amounts of uPA and PAI-2 mRNA were
significantly higher in cancerous relative to normal lung tissues. However, no
significant difference was observed in uPAR and PAI-1 mRNA levels. All
transcripts were present in cancer cells and were predominantly located in tumor
edges in several cases. In addition, PAI-1 transcripts were more abundant in
poorly and moderately differentiated carcinomas relative to well-differentiated
carcinomas and PAI-2 transcripts were more abundant in squamous cell carcinomas
than in adenocarcinomas. Thus, PAIs may be involved in modulation of malignant
potency. Our results indicate that human non-small-cell lung cancer cells can
autonomously express the mRNAs of uPA, uPAR and PAIs, which are possibly involved
in metastasis.
PMID- 9766561
TI - Infection with CagA+ Helicobacter pylori strains as a possible predictor of risk
in the development of gastric adenocarcinoma in Mexico.
AB - Helicobacter pylori strains possessing the Cag pathogenicity island have been
associated with increased gastric inflammation and with duodenal ulcer. In
contrast, studies on the association of cagA+ H. pylori infections and gastric
cancer have shown conflicting results. The aim of our study was to determine
whether H. pylori and CagA status are associated with gastric cancer in Mexico.
We selected serum samples from 3 geographic areas with gastric cancer mortality
rates per 100,000 inhabitants of 2.5 (low risk), 4.5 (medium risk) and 6.4 (high
risk). H. pylori infection was determined by the detection of antibodies to H.
pylori whole cell antigen by an enzyme-linked immunosorbent assay (ELISA). To
study the prevalence of infection with cagA+ strains, serum IgG antibodies to
CagA were determined by ELISA using a recombinant CagA antigen. Of the 2,775
individuals studied, 1,931 were H. pylori seropositive and 1,710 had antibodies
against CagA. The risk for gastric cancer in the 3 populations studied increased
proportionally as infection with cagA+ strains increased (p < 0.001 for trend).
H. pylori infection also showed association with gastric cancer (p < 0.05).
Individuals seropositive for CagA, but seronegative for H. pylori whole cell
antigen, were more frequent in areas with higher gastric cancer rates (p < 0.01).
These results support the possible role of CagA(+) status as predictor of risk
for gastric adenocarcinoma in Mexico; this is in agreement with results in
European and American populations, but contrary to studies in some Asian
countries.
PMID- 9766560
TI - Familial prostate cancer and possible associated malignancies: nation-wide
register cohort study in Sweden.
AB - There is a familial aggregation of prostate cancer, and 5 to 10% of all prostate
cancers are estimated to be inherited in an autosomal-dominant mode. A population
based cohort study was performed in order to study familial prostate cancer and
associated malignancies. A nation-wide register cohort study was conducted using
an unselected study population. The cohort of 5,595 sons and 5,089 daughters of
Swedish men found to have prostate cancer between 1959 and 1963 was identified.
All types of cancer reported between 1958 and 1992 in this cohort were identified
through linkage to the Swedish Cancer Registry. The expected number of different
cancers was calculated using incidence rates obtained from the Registry. A highly
significant increased overall standardized incidence ratio (SIR) of 1.65 (95% CI,
1.49-1.83) was obtained for prostate cancer, with 370 observed cases compared
with 224 expected prostate cancers. The SIR was 3.18 among cases 45 to 49 years
old at diagnosis, with the risk gradually decreasing to a SIR of 1.45 among cases
over 80 years of age. Among sons and daughters with a father whose prostate
cancer was diagnosed at an early age (<70 years), an increased risk for
colorectal cancer SIR 1.48 (1.10-1.95) was observed. No significant difference in
cancer risk for other sites was observed among the daughters and sons of men with
prostate cancer. This cohort study confirms earlier studies that a positive
family history of prostate cancer is an important risk factor for developing this
disease. Though increased risk was found for all ages, it was more pronounced in
younger men. Since no other malignancy was significantly associated with prostate
cancer, it is most likely that familial prostate cancer is "site-specific".
PMID- 9766562
TI - Expression of signal transducing T-cell receptor zeta molecules after adoptive
immunotherapy in patients with gastric and colon cancer.
AB - We and others have shown decreased expression of T-cell receptor-CD3-associated
signal transducing zeta molecules (TCRzeta) in tumor infiltrating and peripheral
T cells of patients with advanced cancer. In the present study, we performed
adoptive immunotherapy (AIT) with tumor-associated lymphocytes (TAL) in patients
with gastric (n = 11) and colon (n = 3) cancer with stage IV and investigated
whether the alteration of signal transducing molecules was observed with AIT,
compared to an untreated control group (n = 13). Autologous TALs isolated from
malignant ascites or pleural effusion were cultured with stimulation of
autologous tumor in the presence of interleukin-2 (IL-2) and were transferred to
the patients. TCR zeta expression in peripheral T cells was measured by flow
cytometric analysis of permeabilized cells with anti-zeta monoclonal antibody
(MAb) (TIA-2) before and after AIT. We confirmed the down-regulation of TCR zeta
expression in peripheral blood lymphocytes (PBL) of patients with gastric and
colon cancer with stage IV compared to healthy donors (n = 15). AIT induced up
regulation of TCR zeta expression in 2 of 14 treated patients, caused no
significant change of TCR zeta expression in 7 patients and induced further down
regulation in 5 patients. The patients who achieved clinical responses (n = 3)
with AIT showed no significant change of TCR zeta expression. On the other hand,
in the control group without adoptive transfer, further down-regulation of TCR
zeta expression was observed during the corresponding periods, paralleling
disease progression. Taken together, TCR zeta expression in the patients was
further down-regulated, corresponding to disease progression in individual cancer
patients. In some patients, AIT could induce increased or stable TCR zeta
expression. The quantitative analysis of TCR zeta expression might provide vital
information that can be used to optimize therapy by preserving immune functions
within cancer patients.
PMID- 9766563
TI - Expression of the ATM gene is significantly reduced in sporadic breast
carcinomas.
AB - The gene mutated in ataxia telangiectasia (A-T) patients (ATM) is located on
chromosome 11q22-23, a region frequently altered in mammary tumors. Patients
homozygous for ATM mutations are prone to develop a variety of different
neoplasms. Female heterozygotes have been reported to carry a 5- to 8-fold
increased risk of breast cancer. However, germline mutations in the ATM gene are
rare in women with sporadic breast carcinomas. Most of the alterations described
in A-T patients result in a functionally inactive ATM protein. Moreover, it has
been suggested that mutations of the ATM gene in A-T patients influence the
amount of ATM mRNA and that this may affect the severity of the disease. In the
present study, we have analyzed ATM transcripts in a series of 39 breast
carcinomas, 14 benign breast lesions and 12 normal breast tissue samples. ATM
mRNA levels were determined by semiquantitative competitive RT-PCR. Competitor
RNA molecules for the ATM gene and the housekeeping gene beta-2-microglobulin
(B2M) were generated by PCR mutagenesis. Low concentrations of ATM transcripts
were detected in breast carcinomas, intermediate levels in benign lesions and
highest levels in normal breast tissue specimens (F-test, p = 0.0013). Our
results indicate that reduced expression of the ATM gene may contribute to the
development and/or malignant progression of breast carcinomas.
PMID- 9766565
TI - Prognostic factors for cutaneous malignant melanoma in Vaud, Switzerland.
AB - We considered, by means of a multivariate approach, trends in survival from
cutaneous malignant melanoma in relation to patient and tumor characteristics,
using data from the Cancer Registry of the Swiss Canton of Vaud. Between 1980 and
1994, 1,229 cases of incident cutaneous malignant melanoma were registered. There
was a decline in the proportion of neoplasms in the head and neck and lower
limbs, and a rise in those of the trunk and upper limbs, an increase in
superficial spreading melanoma and in tumors of limited thickness, mostly in
females. Five-year crude survival was 0.68 for males and 0.82 for females, and
relative survival of 0.79 for males and 0.89 for females, corresponding to a
multivariate hazard ratio (HR) of 0.63 for females vs. males. Survival was
inversely related to age, with 5-year relative survival of 0.92 at age 15-44
years, 0.85 at age 45-64 years, and 0.79 at age > or = 65 years. With reference
to histological type, no significant difference was observed in males, but in
females nodular melanoma showed reduced survival. Compared with melanoma of the
limbs, the HR was 1.46 for melanoma of the trunk, and 1.23 for those in the head
and neck, and the difference was greater in females. A strong relation, in both
sexes, was observed between survival and tumor thickness, with an HR of 3.96 for
tumors > or = 4 mm vs. those < 1.50 mm. After allowance for all other factors
considered, most recent calendar period of diagnosis was associated with improved
survival in both sexes (HR = 0.72), but mostly in females. Although differences
in survival tended to be larger during the first 2 years after diagnosis, the
pattern was similar for most prognostic factors considered up to 10 years after
diagnosis.
PMID- 9766564
TI - Pharmacokinetics and selectivity of aminolevulinic acid-induced porphyrin
synthesis in patients with cervical intra-epithelial neoplasia.
AB - Photodynamic therapy (PDT), due to its tumor selectivity, represents an
alternative approach to diagnose and treat cervical intra-epithelial neoplasia
(CIN) without altering normal surrounding tissue. Our aim was to investigate the
pharmacokinetics and the selectivity of 5-aminolevulinic acid (5-ALA)-induced
porphyrin fluorescence after topical administration, to obtain basic clinical
data for future diagnostic fluorescence imaging and PDT protocols for CIN. Twenty
eight non-pregnant women with a cytological diagnosis of low-grade or high-grade
squamous intra-epithelial lesions were included. An aqueous solution containing
3% 5-ALA was topically applied 1 to 6 hrs prior to conization using a cervical
cap. After excision, porphyrin-induced fluorescence was quantified in dysplastic
(n = 14) and normal epithelium (n = 28) by means of quantitative fluorescence
microscopy. High values of porphyrin fluorescence were found in squamous
epithelium between 150 and 450 min, with a maximum at 300 min following
administration of 5-ALA. Ratios of porphyrin fluorescence of dysplastic vs.
surrounding normal epithelium were 1.3 and 1.21 for CIN 1 (n = 3) and CIN 2 (n =
3), respectively. In CIN 3 patients (n = 8), this ratio was 2.35; the best
selectivity of 5-ALA-induced porphyrin fluorescence in CIN 3 lesions (ratio 3)
was observed with a topical administration time of between 150 and 250 min. Our
results demonstrate that patients with CIN 3 show higher 5-ALA-induced
fluorescence compared with normal epithelium. The optimal administration time of
topically applied 5-ALA was between 3 and 4 hr. Our data suggest that topical ALA
PDT and photodynamic diagnosis might be suitable for detecting CIN.
PMID- 9766566
TI - Analysis of fibrinolytic proteins in relation to DNA ploidy in prostate cancer.
AB - The tissue concentrations of urokinase-type plasminogen activator (u-PA),
urokinase-type plasminogen activator receptor (u-PAR), plasminogen activator
inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were
investigated by an ELISA technique in normal and malignant samples of the
prostate from 24 patients undergoing radical prostatectomy for organ-confined
prostate cancer. The median concentration of u-PA was significantly higher in
cancerous than in normal prostate tissue (p = 0.006). No significant increase of
u-PAR, PAI-1 and t-PA was found in cancer tissue in comparison with the benign
samples (p > 0.05). Assessment of the relationship between fibrinolytic proteins
and DNA ploidy revealed an increased u-PA, u-PAR and PAI-1 in diploid prostate
cancer as compared with the normal controls. However, in aneuploid cancer u-PA
remained high but u-PAR and PAI-1 were decreased. This led to a higher local
concentration of u-PA in aneuploid samples than in normal prostate and in diploid
prostate cancer. No alteration of median t-PA was found in benign prostate or in
diploid or aneuploid prostate cancer. The altered expression of u-PA, u-PAR and
PAI-1 in diploid and aneuploid prostate cancer suggests a possible role of
fibrinolytic proteins in the different biologic behavior of tumors, and may be
one explanation for the higher metastatic potential of aneuploid tumors.
PMID- 9766567
TI - STAT3 mediates the survival signal in oncogenic ras-transfected intestinal
epithelial cells.
AB - The oncogenic ras mutation is a common and critical step in gastrointestinal
carcinogenesis. In a previous study, we demonstrated that oncogenic ras activated
the EGF-related peptide autocrine loop and that the apoptosis resistance observed
in the oncogenic ras-stimulated cell (IEC-ras cell) was dependent on this
activated EGF-related peptide autocrine loop. STATs (signal transducers and
activators of transcription), first identified as intracellular signal
transducers stimulated by cytokines, are known to also be activated by EGF.
However, the role of STATs in the survival signal of IEC-ras cells is not clear.
In the present study, we demonstrate that STAT3 is constitutively activated in
ras-stimulated cells and that STAT3 activation is considerably suppressed by the
EGF-specific receptor kinase inhibitor AG 1478. We also show that disruption of
the STAT3 pathway by introduction of a dominant-negative STAT3 mutant abolishes
the apoptosis resistance against UVC and MMC treatment observed in IEC-ras cells
without affecting proliferation. Moreover, the expression of Bcl-2 and Bcl-xL,
apoptosis-suppressive proteins, is reduced in dominant-negative STAT3-transfected
cells. Thus, STAT3 appears to be an important mediator of the antiapoptotic
signal in IEC-ras cells.
PMID- 9766568
TI - Proteinase requirements of epidermal growth factor-induced ovarian cancer cell
invasion.
AB - Aberrant expression or activity of the epidermal growth factor (EGF) receptor
family of tyrosine kinases has been associated with tumor progression and an
invasive phenotype. In this study, we utilized 4 ovarian cancer cell lines, OVCA
432, DOV 13, OVEA6 and OVCA 429, to determine the effects of EGF on the
regulation of proteolytic enzymes and their inhibitors, cellular migration and in
vitro invasion. Induction of urinary-type plasminogen activator (u-PA) activity
and tissue inhibitor of matrix metalloproteinase (TIMP)-1 was observed in all 4
cell lines. OVCA 432 cells showed strong PAI-1 induction; however, the other 3
lines displayed substantial baseline PAI-1 expression that was not induced by
EGF. EGF-dependent stimulation of migration and induction of matrix
metalloproteinase (MMP)-9 (gelatinase B) was observed in OVEA6 and OVCA 429 cells
only. Upon EGF receptor activation, DOV 13, OVEA6 and OVCA 429 cells were induced
to invade through an artificial basement membrane (Matrigel); however, no
invasion was detected in OVCA 432 cells. Cell lines displaying induction of
migration and MMP-9 (OVEA6 and OVCA 429) demonstrated robust EGF-induced invasion
(5- to 20-fold), and cell invasion was substantially reduced in the presence of
anti-catalytic MMP-9 antibody. Addition of anti-catalytic u-PA antibody inhibited
the modest (<2-fold) EGF-induced invasion in a cell line that did not express MMP
9 (DOV 13) and in OVEA6 cells that displayed the highest baseline u-PA activity.
Together, our findings indicate that multiple proteinases are important in
ovarian cell invasion and implicate EGF induction of MMP-9 and migration as key
components of more aggressive ligand-induced invasion.
PMID- 9766569
TI - Anti-proliferative effect of retinoids and interferon-alpha-2a on vaginal cell
lines derived from squamous intra-epithelial lesions.
AB - A panel of retinoids (all-trans-, 13-cis-, 19-cis retinoic acid and acitretin),
and interferon-alpha-2a was tested for the capacity to modulate the proliferation
of UT-DEC-1 (HPV-33-positive) and UT-DEC-2 (HPV-16-positive) cell lines derived
from vaginal intra-epithelial neoplasias (VAIN). At concentrations 10(-6) to 10(
8) M, all retinoids inhibited the growth of early-passage UT-DEC cell lines, but
also of normal vaginal keratinocytes and fibroblasts. The inhibition was
significantly reduced in late-passage UT-DEC cells. The effect on proliferation
was essentially equal for all retinoids in high (1.8 mM)-Ca2+ medium, but
decreased markedly in low (0.09 mM)-Ca2+ medium. Interferon-alpha-2a at 1000
IU/ml had an additive growth-inhibitory effect in the low- and in the high-Ca2+
medium. No consistent decrease in HPV E6-E7 mRNA levels could be associated
either with retinoid or with interferon effect in either cell line. The
expression of TGFbeta1 and TGFbeta2 mRNA increased 2- to 3-fold by 10(-6) M 13
cis-RA treatment in early- and in late-passage cells of both cell lines. TGFbeta1
at 0.1 to 1.0 ng/ml also inhibited the proliferation of both cell lines, and was
more effective at early passage, but the inhibition was not dependent on calcium
concentration. Neutralizing anti-TGFbeta antibodies partially relieved the
proliferation inhibition by 13-cis-RA. The results show that the calcium
associated regulation of growth by the tested retinoids was seen in normal
vaginal cells and in early pre-neoplastic cells, but was significantly reduced in
cells with higher-grade phenotype, while also suggesting that the loss of
responsiveness to retinoids and TGFbeta may play a role in the progression of
squamous intra-epithelial neoplasia.
PMID- 9766570
TI - DNA interaction and cytostatic activity of the new liver organotropic complex of
cisplatin with glycocholic acid: Bamet-R2.
AB - The aim of this study was to investigate the ability of the new liver
organotropic complex of cisplatin with glycocholate (GC), Bamet-R2, to interact
with DNA, inhibit its replication and hence reduce tumor-cell proliferation.
Changes in the electrophoretic mobility of the open and covalently closed
circular forms of the pUC18 plasmid DNA from Escherichia coli, a shift in the
denaturation temperature of double-stranded DNA, and ethidium-bromide
displacement from DNA binding, were induced by Bamet-R2 and cisplatin, but not by
GC. Neutral-red retention was used to measure the number of living cells in
culture after long-term (72-hr) exposure to these compounds and to evaluate the
effect on cell viability after short-term (6-hr) exposure. Bamet-R2 and
cisplatin, but not GC, induced significant inhibition of cell growth. This effect
ranged from mild to strong, depending upon the sensitivity of the different cell
types as follows: cisplatin, rat hepatocytes in primary culture < rat hepatoma
McA-RH7777 cells (rH) < human colon carcinoma LS 174T cells (hCC) < mouse
hepatoma Hepa 1-6 cells (mH); Bamet-R2, rat hepatocytes < mH approximately equal
to hCC < rH. DNA synthesis was measured by radiolabeled-thymidine incorporation
into DNA. Bamet-R2 and cisplatin, but not GC, significantly inhibited the rate of
DNA synthesis by these cells. After short-term exposure to Bamet-R2 or GC, no
acute cell toxicity was observed, except on hCC cells. By contrast, acute
toxicity was induced by cisplatin for all cell types studied. The in vivo anti
tumoral effect was investigated in 3 different strains of mice following s.c.
implantation of tumor cells (mouse sarcoma S-18011 cells in Swiss and B6 mice and
hCC cells in nude mice). In all 3 models, tumor growth was inhibited by Bamet-R2
and cisplatin to a similar degree. However, signs of toxicity (increases in blood
urea concentrations and decreases in packed blood cell volume and in liver,
kidney and body weight) and a reduction in survival rate were observed only
during cisplatin administration. In sum, these results indicate that this bile
acid derivative can be considered as a cytostatic drug whose potential usefulness
deserves further investigation.
PMID- 9766571
TI - Hyperglycemia regulates the glucose-transport system of clonal choriocarcinoma
cells in vitro. A potential molecular mechanism contributing to the adjunct
effect of glucose in tumor therapy.
AB - Glucose is taken up by tumor cells via sodium-independent facilitated diffusion
along a concentration gradient. To examine the regulation of this process by
substrate concentration, we investigated the effect of hyperglycemia on the
glucose-transport system of choriocarcinoma-derived JAR and JEG-3 cells by
culturing them for 24, 48 and 96 hr in medium containing either 5.5
(normoglycemia) or 25 (hyperglycemia) mM D-glucose, respectively.
Immunocytochemically, choriocarcinoma cells expressed the high-affinity glucose
transporter isoforms GLUT1 and GLUT3. Based on initial uptake measurements using
3-O-[14C]methyl-D-glucose, kinetic parameters were calculated as Km = 15 mM and
Vmax = 95 fmol/sec per cell for JAR and Km = 9 mM and Vmax = 64 fmol/sec per cell
for JEG-3 cells. In JAR cells cultured under hyperglycemic conditions, uptake
rates were significantly increased at 15, 20 and 25 mM exogenous D-glucose
concentrations as compared with normoglycemic conditions. This effect was due to
an increase in Vmax, whereas Km remained unchanged. Using Northern blotting,
GLUT1 mRNA levels were higher but GLUT3 transcripts were reduced upon
hyperglycemia. Western blotting revealed elevated GLUT1 and GLUT3 expression
under hyperglycemic conditions. Hyperglycemia did not significantly influence the
glucose-transport system of JEG-3 cells. We conclude that sustained hyperglycemia
stimulates the glucose-transport system of JAR, but not of JEG-3, choriocarcinoma
cells in vitro due to changes in GLUT1 and GLUT3 expression levels. We speculate
that this mechanism may contribute to the beneficial effects of induced
hyperglycemia as an adjuvant in tumor therapy.
PMID- 9766572
TI - IL-12 regulates VEGF and MMPs in a murine breast cancer model.
AB - In a murine model of breast cancer, IL-12 therapy exerts potent anti-angiogenic
effects which contribute to tumor regression. After 7 days of treatment, levels
of tumor VEGF protein decline markedly and are undetectable at 14 days. This
decline is accompanied by a fall in MMP-9 and, as the tumors regress, an increase
in its natural inhibitor, TIMP-1. A cell line established from the primary tumor
produced VEGF in vitro. IFN-gamma reduced tumor cell production of VEGF over a 24
hr period in vitro, suggesting that IL-12-induced IFN-gamma may be responsible
for the decline in VEGF levels in vivo. There is also in vitro evidence that IL
12 regulates stromal cell interactions, leading to decreased MMP-9 and increased
TIMP-1 production. Thus, we suggest that at least 2 mechanisms are involved in IL
12 regulation of angiogenesis, removing the pro-angiogenic stimulus and blocking
the release and activity of MMPs.
PMID- 9766573
TI - Suppression of Erk activation and in vivo growth in esophageal cancer cells by
the dominant negative Ras mutant, N116Y.
AB - Our previous studies demonstrated that introduction of a dominant negative H-ras
mutant, N116Y, inhibits the growth of various types of cancer cells in vitro. In
this study, we tested the efficacy of N116Y in blocking the growth of esophageal
cancer cells using an adenoviral vector. Infection with N116Y adenovirus, (AdCMV
N116Y), in which N116Y expression is driven by the cytomegalovirus promoter,
significantly reduced the in vitro growth of all esophageal cancer cell lines
studied. Esophageal cancer cells that contained wild-type K-ras and H-ras (TE8,
SGF3, SGF7) were more sensitive to AdCMV-N116Y than HEC46 cells that expressed
mutant K-ras protein. Most importantly, direct injection of AdCMV-N116Y into TE8-
or SGF3-induced tumors in nude mice suppressed their growth significantly. To
examine the suppressive mechanism of N116Y, cell cycle profile and the activation
of extracellular signal-regulated kinase 2 (Erk2) were examined by flow cytometry
and Western blot analysis, respectively. In TE8 cells, progression into S phase
was clearly blocked after infection with AdCMV-N116Y. Infection with AdCMV-N116Y
did not strongly suppress the activation of Erk2 after EGF stimulation in serum
starved HEC46 cells, whereas it completely suppressed activation in TE8, SGF3 and
SGF7 cells. Our observations suggest that N116Y reduces growth of human
esophageal cancer cells and suppresses the activation of Erk2; they also indicate
that N116Y is a potential candidate gene for human esophageal cancer gene
therapy.
PMID- 9766574
TI - Characterization of p53 mutants identified in human tumors with a missense
mutation in the tetramerization domain.
AB - p53 is very often mutated in human cancers. The majority of alterations are
missense mutations located within the DNA-binding domain of the protein. Many
reports have characterized such mutant proteins. Little is known, however, about
the properties of proteins that have a missense mutation outside this domain. We
investigated here the properties of 8 mutant proteins identified in human tumors
as having a missense mutation in the tetramerization domain. The Arg342Gln,
Glu349Asp and Gln354Arg proteins behaved like wild-type both in vitro and in
cells. Two mutants, Arg342Pro and Leu344Pro, were inactive in all assays.
Finally, the 3 mutant proteins Leu330His, Arg337Cys and Arg337Leu, which are
inactive in vitro, showed no activity at low expression levels in cells but
became active at higher expression levels. Our results reveal new phenotypes for
p53 mutants and suggest that sequencing of the p53 gene from patients with tumors
should be extended to exons 9 and 10 in clinical investigations.
PMID- 9766576
TI - Does wheat bran or does wheat dietary fibre protect against breast cancer?
PMID- 9766575
TI - Lonidamine as a modulator of taxol activity in human ovarian cancer cells:
effects on cell cycle and induction of apoptosis.
AB - The ability of lonidamine (LND), an energolytic derivative of indazole-carboxylic
acid, to modulate the cytotoxicity of Taxol (TX) was investigated in the A2780
human ovarian cancer cell line. Different cytotoxicity results were obtained as a
function of treatment schedule. Specifically, TX followed by LND produced
synergistic effects. Conversely, antagonistic effects were recorded when drugs
were given simultaneously or according to the opposite sequence. TX induced an
oligonucleosomal DNA fragmentation typical of the apoptotic process. The extent
and the kinetics of DNA cleavage in samples treated with the taxane alone were
similar to those of samples treated with the TX-LND sequence. Activation of Yama
protease and degradation of poly (ADP-ribose) polymerase were not observed after
individual or combined treatment. LND did not appreciably modify the effect
exerted by TX on proteins involved in cell cycle progression (i.e., inhibition of
p34cdc2 expression) and apoptosis (i.e., upregulation of wt p53 and
transactivation of p21waf1), and only caused a slight induction of the Bax
protein. LND alone did not affect tubulin polymerization in A2780 cells and, when
administered after a 24 hr TX exposure, did not appreciably alter the extent of
tubulin polymerization induced by the taxane. Although additional studies are
needed to define the molecular basis of the TX-LND interaction, our results
suggest that LND can positively modulate the antitumor activity of TX in ovarian
cancer cells and indicate that the energolytic is potentially useful in
combination therapy including the taxane in ovarian cancer patients.
PMID- 9766577
TI - Expression of multiple cancer/testis (CT) antigens in breast cancer and melanoma:
basis for polyvalent CT vaccine strategies.
PMID- 9766578
TI - p53 antibodies in the saliva of patients with squamous cell carcinoma of the oral
cavity.
PMID- 9766579
TI - Matrix metalloproteinase-2 in blood does not indicate the progression of prostate
cancer.
PMID- 9766580
TI - Long-term survival from uterine cervical cancer in Mumbai (Bombay), India.
PMID- 9766581
TI - Surgery for esophageal cancer in elderly patients: the view from Nottingham.
AB - OBJECTIVE: Our aim was to compare the outcome of esophageal resection for
carcinoma in elderly patients (aged over 70 and over 80 years) with that of
younger patients managed within a single specialist thoracic surgery unit.
PATIENTS AND METHODS: Between January 1987 and November 1997, 523 patients
underwent esophagectomy for carcinoma in the Nottingham City Hospital Thoracic
Surgery Unit. The patients were divided into 3 groups by age: group I, under 70
years (n = 337); group II, 70 to 79 years (n = 150), and group III, 80 to 86
years (n = 36). These groups were compared with regard to preoperative medical
status, operability and resectability, complications, operative mortality, and
longterm survival. RESULTS: Patients in groups II (6.0%) and III (2.8%) had fewer
preexisting respiratory problems than patients in group I (12.5%), and the
patients in group III had fewer preexisting cardiovascular problems (16.7%) than
patients in groups I (25.2%) and II (32.7 %). Although patients in group III were
generally less likely to have operable lesions (64.3%), no significant
differences in resectability rate were detected among the 3 groups (80.8%, 77.7%,
and 80%). Elderly patients (groups II and III) had a higher incidence of overall
(34% and 36.1%), respiratory (24.7% and 19.4%), and cardiovascular (7.3% and
11.1%) complications than those aged under 70 years (24.6%, 16.3%, and 2.1%,
respectively). However, operative mortality (4.7%, 6.7%, and 5.6%) and 5-year
survivals inclusive of operative mortality (25.1%, 21.2%, and 19.8%) were similar
among the 3 groups. CONCLUSIONS: Accumulated experience in all aspects of
perioperative management may account for a low hospital mortality in elderly
patients despite a greater operative risk. The survival benefit is similar to
that in the younger age groups, enforcing the view that esophagectomy within
specialist thoracic units can be safely offered (in appropriately selected
patients) with acceptable long-term survival in all age groups.
PMID- 9766582
TI - Transesophageal biopsy of mediastinal and pulmonary tumors by means of endoscopic
ultrasound guidance.
AB - OBJECTIVE: The aim of this study was to investigate the value of endoscopic
ultrasound-guided biopsy for the diagnosis of thoracic lesions. METHODS:
Transesophageal ultrasound-guided biopsy was performed in 29 patients with
mediastinal (n = 25) or pulmonary tumors (n = 4). A flexible echoendoscope with a
7.5 MHz curved array transducer (Pentax FG 32 UA, Hamburg, Germany) and a biopsy
device with a fine needle (diameter 0.8 mm) were used for all examinations. Three
patients were excluded from the analysis of the data because a definite diagnosis
based on surgery or follow-up was not available. RESULTS: Real-time visualization
of the biopsy procedure with endoscopic ultrasound enabled accurate tissue
sampling even of small mediastinal lesions with a diameter of less than 1 cm.
Diagnostic material was obtained in 23 of the 26 patients (88%). In 3 cases (12%)
non-representative biopsy material was found in the specimen. The sensitivity and
specificity of transesophageal biopsy in the diagnosis of malignancy were 89% and
83%, respectively. Histologic analysis of the biopsy specimens established
malignancy in 17 of 23 patients, whereas benign lesions were diagnosed in 6
patients. Endoscopic ultrasound-guided biopsy confirmed the diagnosis suggested
by conventional diagnostic methods in 15 of 23 patients (65%), whereas an
unsuspected diagnosis was disclosed in 8 patients (35%). The results of the
biopsy had considerable impact on the therapeutic strategy. None of the patients
had complications related to the procedure. CONCLUSIONS: Endoscopic ultrasound
guided biopsy provides a new minimally invasive approach to the biopsy of lesions
in the posterior mediastinum and may complement surgical staging procedures.
PMID- 9766583
TI - Recurrent aortic coarctation: is surgical repair still the gold standard?
AB - OBJECTIVE: We reviewed our experience with surgical repair compared with balloon
aortoplasty of recurrent coarctations of the aorta. METHODS: This is a
retrospective review of 1 institution's 27-year experience with surgical repair
of recurrent aortic coarctation. A thorough chart review was performed of all
pediatric patients undergoing surgical repair for recurrent aortic coarctation (n
= 56) from January 1970 through July 1996. RESULTS: The vast majority of
recoarctations were repaired with a prosthetic patch technique, with a greater
than 96% success rate. No deaths or major complications occurred in the 56
patients. Although a direct comparison with balloon aortoplasty cannot be done,
we have reviewed the data available in the literature and found higher
complication rates and lower success rates than we obtained in our series.
CONCLUSIONS: Although the treatment of aortic coarctation has improved
significantly during the past decades, persistent hypertension after repairs at
an older age and recurrent coarctation after repairs in neonates occur in all
institutions. Surgeons have not agreed on the optimal approach to primary
coarctation repair, and invasive cardiologists have challenged operative
intervention for both recurrent and primary coarctation. This study demonstrates
that surgical repair of recurrent coarctation of the aorta can be performed
safely and with excellent results. We believe it is still the gold standard in
the management of recurrent coarctation of the aorta.
PMID- 9766584
TI - The effect of ventricular volume reduction surgery in the dilated, poorly
contractile left ventricle: a simple finite element analysis.
AB - OBJECTIVES: Ventricular volume reduction surgery has been proposed by Batista to
improve cardiac function in patients with dilated cardiomyopathy. However,
limited clinical data exist to determine the efficacy of this operation. A finite
element simulation is therefore used to determine the effect of volume reduction
surgery on left ventricular end-systolic elastance, diastolic compliance, stroke
work/end-diastolic volume (preload recruitable stroke work), and stroke work/end
diastolic pressure (Starling) relationships. METHODS: End-diastole and end
systole were represented by elastic finite element models with different unloaded
shapes and nonlinear material properties. End-systolic elastance, diastolic
compliance, preload recruitable stroke work, and Starling relationships, as well
as energy expenditure per gram of unresected myocardium, were calculated. Two
different types of volume reduction surgery (apical and lateral) were simulated
at 10% and 20% left ventricular mass reduction. RESULTS: Ventricular volume
reduction surgery causes diastolic compliance to shift further to the left on the
pressure-volume diagram than end-systolic elastance. Volume reduction surgery
increases the slope of the preload recruitable stroke work relationship (dilated
cardiomyopathy 0.006 J/mL; 20% lateral volume reduction surgery 0.009 J/mL) but
decreases the slope of the Starling relationship (dilated cardiomyopathy 0.028
J/mm Hg; 20% lateral volume reduction 0.023 J/mm Hg). For a given amount of
resection, lateral volume reduction has a greater effect than apical volume
reduction. Ten-percent and 20% lateral volume reduction reduces energy
expenditure by 7% and 17%, respectively. CONCLUSION: Ventricular volume reduction
surgery shifts end-systolic elastance and diastolic compliance to the left on the
pressure-volume diagram. The net effect on ventricular function is mixed. Volume
reduction surgery increases the slope of preload recruitable stroke work, but
increased diastolic compliance causes a small decrease in the Starling
relationship (3 mm Hg difference between dilated cardiomyopathy and volume
reduction surgery at stroke work = 0.5 J).
PMID- 9766585
TI - Large encircling cryoablation without mapping for ventricular tachycardia after
anterior myocardial infarction: long-term outcome.
AB - OBJECTIVE: Map-guided procedures have been the accepted standard for ventricular
tachycardia surgery. However, promising results of visually guided resections
without mapping have been reported. The goal of this study was to evaluate the
efficacy of large encircling cryoablation without mapping for ventricular
tachycardia after anterior myocardial infarction. METHODS: Between 1985 and 1996,
this procedure, along with aneurysmectomy, was performed on 38 patients for
malignant ventricular tachycardia. The mean interval between the operation and
myocardial infarction was 59.2 months; 7 patients (18.4%) were operated on within
1 month of myocardial infarction. The mean patient age was 62.1 +/-7.3 years and
the mean left ventricular ejection fraction was 29.0% +/-7.2%. RESULTS: Hospital
mortality was 2.6% (1 patient). The electrical success rate based on
postoperative electrophysiologic studies was 94.5%. Overall electrical success
rate was 89.1%. Freedom from ventricular tachycardia was 77% (95% CI 61%-94%) at
both 5 and 7 years. Freedom from sudden cardiac death was 91% (95% CI 80%-100%)
at both 5 and 7 years, with overall actuarial survivals at 5 and 7 years of 63%
(95% CI 47%-80%) and 42% (95% CI 22%-63%), respectively. The main cause of late
death was congestive heart failure in 62.6% of these patients. CONCLUSIONS: One
can achieve good results without intraoperative mapping in the treatment of
patients with ventricular tachycardia after anterior myocardial infarction by
using large encircling cryoablation.
PMID- 9766586
TI - Preoperative risk models for minimally invasive coronary bypass: a preliminary
study.
AB - OBJECTIVE: Available risk assessment models are designed for standard coronary
artery bypass grafting. We hypothesized that minimally invasive coronary bypass
could improve on predicted outcome in extremely high-risk patients (Parsonnet
score > 20%) by the current risk models. METHODS: From September 1996 to
September 1997, 27 consecutive extremely high-risk patients underwent minimally
invasive coronary bypass. Seventeen patients were male; age was 73 +/- 12 years,
and 63% of patients were older than 75 years. Left ventricular ejection fraction
was 33.7% +/- 15% and 63% had an ejection fraction of less than 35%. The
predicted 30-day mortality according to the System 97 model was 25.6% +/- 11.3%.
The Parsonnet risk score was 36.2% +/- 11%; the predicted length of stay in the
hospital was 15.3 +/- 3 days. The predicted risk of stroke according to the
Multicenter Perioperative Stroke Risk Index was 22.3% +/- 11.7%. RESULTS:
Minimally invasive coronary bypass was isolated in 20 patients and integrated
with angioplasty and stenting in 7 patients. The observed 30-day mortality was 0%
(P < .01 vs predicted): at an average follow-up of 10.8 +/- 4.1 months, 26
patients (96.3%) are alive without angina; one patient with acquired
immunodeficiency syndrome died on postoperative day 40 of acute pancreatitis. No
patient had a stroke or neurologic deficit (P < .01 vs predicted). Patency of
internal thoracic artery anastomosis was confirmed by angiography in all 27
patients. No patient required reoperation. Eighteen patients (67%) were extubated
in the operating room. The observed length of hospital stay after minimally
invasive coronary bypass was 3.8 +/- 2.6 days (P < .01 vs predicted). CONCLUSION:
On the basis of our results on a relatively small series of patients, we suggest
that risk models geared for standard coronary bypass grafting may not be
appropriate for minimally invasive coronary bypass.
PMID- 9766587
TI - Regression of left ventricular hypertrophy after aortic valve replacement for
aortic stenosis with different valve substitutes.
AB - OBJECTIVE: Stentless biologic aortic valves are less obstructive than stented
biologic or mechanical valves. Their superior hemodynamic performances are
expected to reflect in better regression of left ventricular hypertrophy. We
compared the regression of left ventricular hypertrophy in 3 groups of patients
undergoing aortic valve replacement for severe aortic stenosis. Group I (10
patients) received stentless biologic aortic valves, group II (10 patients)
received stented biologic aortic valves, and group III (10 patients) received
bileaflet mechanical aortic valves. METHODS: Echocardiographic evaluations were
performed before the operation and after 1 year, and the results were compared
with those of a control group. Left ventricular diameters and function, left
ventricular wall thickness, and left ventricular mass were assessed by
echocardiography. RESULTS: Group I patients had a significantly lower maximum and
mean transprosthetic gradient than the other valve groups (P = .001). One year
after operation there was a significant reduction in left ventricular mass for
all patient groups (P < .01), but mass did not reach normal values (P = .05).
Although the rate of regression in the interventricular septum and posterior wall
thickness differed slightly among groups, their values at follow-up were
comparable and still higher than control values (P = .002). The ratio between
interventricular septum and posterior wall and the ratio between wall thickness
and chamber radius did not change significantly at follow-up. CONCLUSIONS:
Because the number of patients was relatively small, we could not use left
ventricular mass regression after I year to distinguish among patients undergoing
aortic valve replacement for aortic stenosis by means of valve prostheses with
different hemodynamic performances.
PMID- 9766588
TI - Long-term Doppler echocardiographic results of aortic or mitral valve replacement
with Biocor porcine bioprosthesis.
AB - OBJECTIVES: Our objectives were to evaluate the long-term bioprosthetic and
cardiac functional outcome after insertion (over a 10-year period) of a new
generation porcine zero pressure-fixed Biocor bioprosthesis, as well as to
determine the echocardiographic accuracy for selection of patients requiring
reoperation. The long-term systematic Doppler echocardiographic assessment after
valve replacement with this bioprosthesis is lacking. METHODS: Between January
1983 and January 1993, we inserted 756 Biocor prostheses in the aortic (619) or
mitral (137) positions. All 51 patients who had a reoperation during the follow
up time were evaluated echocardiographically before reoperation. Additionally,
263 of 446 patients (59%) with aortic bioprostheses and 42 of 74 patients (57%)
with mitral bioprostheses who were alive in January 1993 had long-term
echocardiographic follow-up. RESULTS: Group A: Normally functioning bioprostheses
were found in the aortic position in 242 of 263 patients and in the mitral
position in 33 of 42 patients. Group B: Thirty patients had abnormal
bioprosthetic function. Eleven patients had regurgitation, 3 had a combined
lesion, and signs of calcification appeared in 16 patients with aortic valves,
all with a peak gradient of above 60 mm Hg. Group C: Patients who had a
reoperation (41 aortic and 10 mitral) within the follow-up period were followed
up echocardiographically from the detection of a possible valve dysfunction until
reoperation, and the findings accorded well with those at operation in 49 of 51
patients. CONCLUSIONS: These findings suggest that, during a long-term follow-up,
most bioprostheses function normally, facilitating improved heart function.
Abnormalities in a bioprosthesis usually develop gradually, enabling their
detection by Doppler echocardiographic evaluations performed regularly or in case
of any symptomatic deterioration.
PMID- 9766589
TI - Cardiac valve endothelial cells: relevance in the long-term function of biologic
valve prostheses.
AB - OBJECTIVE: For reasons that are still unclear, biologic heart valve prostheses
undergo degeneration after implantation. We studied the possible role of the
immune system in this process. METHODS: We examined the expression of
immunologically relevant molecules by human cardiac valve endothelium in situ and
in vitro and studied re-endothelialization of implanted allogeneic and xenogeneic
valvular surfaces using explanted bioprostheses and valves obtained from donor
hearts at cardiac retransplantation. RESULTS: We demonstrate that human cardiac
valve endothelial cells express molecules capable of initiating immune responses
and might therefore play a role in the degeneration of viable cardiac valve
prostheses. Also, we show evidence of re-endothelialization on the surfaces of
xenografts and allografts but not on valves obtained from previously transplanted
hearts. CONCLUSION: Inasmuch as valves from previously transplanted hearts seem
to be free from degeneration, we conclude that reduction of the immunogenicity of
allograft valve prostheses by HLA matching or immunosuppressive treatment might
further improve long-term results after allograft valve replacement.
PMID- 9766590
TI - Adenovirus infection in the lung results in graft failure after lung
transplantation.
AB - OBJECTIVES: Our goal was to examine the relationship between viral pneumonia and
outcome in pediatric patients undergoing lung or heart-lung transplantation.
METHODS: Prospective surveillance for common respiratory viruses of childhood was
performed in all patients undergoing lung or heart-lung transplantation.
Specimens were examined for the presence of replicating virus (by culture), viral
genome (by polymerase chain reaction), and viral antigen (by immunofluorescence
and immunohistochemical staining). The relationship between viral infection and
outcome was examined. RESULTS: Sixteen patients underwent 19 transplants during
the study period, with follow-up of 1 to 26 months. Virus was identified in the
transplanted lung in 29 instances; adenovirus was identified most commonly (8/16
patients) and had the greatest impact on outcome. In 2 patients with early,
fulminant infection, adenovirus was also identified in the donor. Adenovirus was
significantly associated with respiratory failure leading to death or graft loss
and with the histologic diagnosis of obliterative bronchiolitis (P < or = .002 in
each case). CONCLUSIONS: Adenovirus infection in the transplanted lung is
significantly associated with graft failure, histologic obliterative
bronchiolitis, and death. Health care personnel and families must be vigilant in
preventing exposure of transplant recipients to this virus. Availability of a
rapid and reliable test for adenovirus in donors and recipients would have an
impact on management and could improve outcome for pediatric lung recipients.
PMID- 9766591
TI - Epithelial regeneration and preservation of tracheal cartilage after tracheal
replacement with cryopreserved allograft in the rat.
AB - OBJECTIVE: We investigated the origin of the epithelium in transplanted
cryopreserved tracheal allografts in rats and tried to clarify the mechanism by
which immunogenicity is reduced in this procedure. METHODS: Tracheal
transplantation was performed with PVG rats (allele at the RT1 locus: c) used as
donors and ACI rats (allele at the RT1 locus: a) as recipients. After resection
of a 5-ring segment of the cervical trachea of an ACI rat, the trachea was
reconstructed with the cryopreserved tracheal segment of a PVG rat (n = 6). No
immunosuppressive agents or steroids were given. Histologic changes were
determined and immunohistochemical staining was performed to investigate major
histocompatibility complex class I antigens of the transplanted tracheal segment.
RESULTS: Two months after tracheal transplantation, 6 surviving ACI rats were
killed. Histologically, the epithelium and tracheal cartilage of the transplanted
cryopreserved segment displayed normal structure. Immunohistochemical staining
showed that the major histocompatibility complex class I antigen of the ACI rat
was expressed in the epithelium of the transplanted segment and that the class I
antigen of the PVG rat was expressed in the cartilage of the transplanted
segment. CONCLUSIONS: After transplantation of the cryopreserved trachea, the
epithelium of the transplanted cryopreserved segment originated from the
recipient epithelium whereas the cartilage retained the structure of the donor
trachea. We hypothesize that transplantation of a cryopreserved trachea leads to
the growth of the recipient's epithelium over the donor trachea, thereby reducing
the antigenicity of the transplant.
PMID- 9766592
TI - A prospective comparison of atrio-femoral and femoro-atrial flow in adult
venovenous extracorporeal life support.
AB - INTRODUCTION: In the United States, venovenous extracorporeal life support has
traditionally been performed with atrial drainage and femoral reinfusion (atrio
femoral flow). Although flow reversal (femoro-atrial flow) may alter
recirculation and extracorporeal flow, no direct comparison of these 2 modes has
been undertaken. OBJECTIVE: Our goal was to prospectively compare atrio-femoral
and femoro-atrial flow in adult venovenous extracorporeal life support for
respiratory failure. METHODS: A modified bridge enabling conversion between atrio
femoral and femoro-atrial flow was incorporated in the extracorporeal circuit.
Bypass was initiated in the direction that provided the highest pulmonary
arterial mixed venous oxygen saturation, and the following measurements were
taken: (1) maximum extracorporeal flow, (2) highest achievable pulmonary arterial
mixed venous oxygen saturation, and (3) flow required to maintain the same
pulmonary arterial mixed venous oxygen saturation in both directions. Flow
direction was then reversed, and the measurements were repeated. Data were
compared with paired t tests and are presented as mean +/- standard deviation.
RESULTS: Ten patients were studied, and 9 were included in the data analysis.
Femoro-atrial bypass provided (1) higher maximal extracorporeal flow (femoro
atrial flow = 55.6 +/- 9.8 mL/kg per minute, atrio-femoral flow = 51.1 +/- 11.1
mL/kg per minute; P = .04) and (2) higher pulmonary arterial mixed venous oxygen
saturation (femoroatrial flow = 89.9% +/- 6.6%, atrio-femoral flow = 83.2% +/-
4.2%; P = .006); (3) furthermore, it required less flow to maintain an equivalent
pulmonary arterial mixed venous oxygen saturation (femoro-atrial flow = 37.0 +/-
12.2 mL/kg per minute, atrio-femoral flow = 46.4 +/- 8.8 mL/kg per minute; P =
.04). CONCLUSIONS: During venovenous extracorporeal life support, femoro-atrial
bypass provided higher maximal extracorporeal flow, higher pulmonary arterial
mixed venous oxygen saturation, and required comparatively less flow to maintain
an equivalent mixed venous oxygen saturation than did atrio-femoral bypass.
PMID- 9766593
TI - Importance of preoperative liver function as a predictor of survival in patients
supported with Thoratec ventricular assist devices as a bridge to
transplantation.
AB - Patient selection is crucial for the success of ventricular assist devices as a
bridge to heart transplantation. PURPOSE: The objective of this study was to
identify preoperative markers for survival and end-organ recovery in patients
having a ventricular assist device. METHODS: A retrospective study was performed
on 32 severely ill patients with end-stage cardiac failure being mechanically
bridged to heart transplantation with the Thoratec Ventricular Assist Device
System (Thoratec Laboratories Corporation, Pleasanton, Calif) in a single center
between 1984 and 1995. The preoperative cardiac index averaged 1.6 L/min per
square meter with a pulmonary capillary wedge pressure of 29 mm Hg. Because of a
high incidence of hepatic or renal dysfunction, or both (total bilirubin: 3.5 +/-
6.2 mg/dL; creatinine: 2.0 +/- 1.3 mg/dL), biventricular support was used in most
patients (28/32). A total of 30 preoperative and 4 perioperative variables were
evaluated for their association with survival and liver recovery. RESULTS:
Nineteen patients (59.4%) survived to transplantation and 13 died. All 19
patients undergoing transplantation were discharged alive with a 1-year survival
of 94.4%. All patients without liver recovery died of multiorgan failure. Direct
and indirect bilirubin measurements were the only significant predictors for
survival to discharge (P = .036, .045); all other factors failed to show
significance. As direct bilirubin levels increased (normal range, 3 times normal,
and >3 times normal), patient survival decreased (82 %, 56%, and 33 %,
respectively). In addition, bilirubin and liver enzyme levels before insertion of
the assist device were significantly associated with liver recovery during
support with the device. CONCLUSION: In our patient population with ventricular
assist devices, liver function is the most predictive factor of patient survival
in bridging to transplantation.
PMID- 9766594
TI - Platelet-rich plasmapheresis in cardiac surgery: a meta-analysis of the effect on
transfusion requirements.
AB - OBJECTIVE: Our purpose was to determine whether intraoperative platelet-rich
plasmapheresis in cardiac surgery is effective in reducing the proportion of
patients exposed to allogeneic red cell transfusions. METHODS: A systematic
search for prospective, randomized trials of platelet-rich plasmapheresis in
cardiac surgery, using MEDLINE, HEALTHSTAR, Current Contents, "Biological
Abstracts," and EMBASE/Excerpta Medica up to August 1997, was completed. Trials
were included if they reported either the proportion of patients exposed to
allogeneic red cells or the units of allogeneic red cells transfused. Trials were
abstracted by 2 independent investigators and the quality of trial design was
assessed with the use of a validated scale. RESULTS: Seventeen references met the
inclusion criteria (1369 patients [675 control: 694 platelet-rich
plasmapheresis]). Platelet-rich plasmapheresis reduced the likelihood of exposure
to allogeneic red cells in cardiac surgery (odds ratio 0.44; 95% confidence
interval 0.27, 0.72, P = .001). Platelet-rich plasmapheresis had a small but
statistically significant effect on both the volume of blood lost in the first 24
hours (weighted mean difference -102 mL; 95% confidence interval -148, -55 mL, P
< .0001) and the mean units transfused (weighted mean difference -0.33 units; 95%
confidence interval -0.43, -0.23, P < .0001). However, platelet-rich
plasmapheresis was only marginally effective (odds ratio 0.83, 95% confidence
interval 0.34, 2.01, P = .68) for "good" quality trials, whereas it appeared very
effective in trials with poor methodologic quality (odds ratio 0.33, 95%
confidence interval 0.17, 0.62, P = .0007). CONCLUSIONS: Although platelet-rich
plasmapheresis appeared effective in decreasing the proportion of patients
receiving transfusions after cardiac operations, the quality of most of the
supporting trials was low and the benefit was small in trials of good quality.
Further clinical trials should be completed.
PMID- 9766595
TI - Successful bilobectomy for pulmonary venous obstruction after bilateral lung
transplantation.
PMID- 9766596
TI - Aggressive surgery for treating a pulmonary metastasis of a benign giant cell
tumor of the bone: results in four cases.
PMID- 9766597
TI - Is complete systematic nodal dissection by thoracoscopic surgery possible? A
prospective trial of video-assisted lobectomy for cancer of the right lung.
PMID- 9766598
TI - Paraplegia after surgery of the thoracic esophagus.
PMID- 9766599
TI - Rhadbdomyolysis after coronary artery bypass grafting in a patient receiving
simvastatin.
PMID- 9766600
TI - Myxoma of right femoral vein origin presenting as a right atrial mass with
syncope.
PMID- 9766601
TI - Coarctation of the aorta with right aortic arch and isolation of the left
innominate artery: a surgical challenge in a patient without collateral posterior
brain circulation.
PMID- 9766602
TI - Rupture of the ascending aorta in Ehlers-Danlos syndrome after surgical repair of
multiple arteriovenous malformations with the use of cardiopulmonary bypass.
PMID- 9766603
TI - Cerebral venous thrombosis after the Fontan procedure.
PMID- 9766604
TI - Modification of anterior approach to superior sulcus tumors.
PMID- 9766605
TI - Leiomyosarcoma of the pulmonary veins extending into the left atrium or left
atrial leiomyosarcoma: multimodality therapy.
PMID- 9766606
TI - The addition of saphenous vein graft to the left anterior descending artery in
left internal thoracic artery hypoperfusion syndrome.
PMID- 9766607
TI - Use of ultracision harmonic scalpel for isolation of intramyocardial coronary
vessels during coronary revascularization of the beating heart.
PMID- 9766608
TI - Axillary artery-coronary artery bypass grafting in patients with atherosclerotic
ascending aorta.
PMID- 9766609
TI - Can you top this?
PMID- 9766610
TI - Delayed iatrogenic aortic dissection from coronary bypass.
PMID- 9766611
TI - Fiftieth anniversary of the insertion of an artificial heart valve.
PMID- 9766612
TI - Historical perspectives of the American Association for Thoracic Surgery. Ethan
Flagg Butler (1884-1964).
PMID- 9766613
TI - Measuring outcome in schizophrenia: differences among the atypical
antipsychotics. Collaborative Working Group on Clinical Trial Evaluations.
AB - The advent of the atypical antipsychotics marked a new era in the history of the
treatment of psychotic disorders. To evaluate the published literature about the
available atypical antipsychotics--clozapine, risperidone, olanzapine, and
quetiapine--and select the most appropriate treatment for specific patients,
physicians need to understand the outcome measures used in clinical studies, the
pharmacologic differences that explain varying side effect profiles, and
pharmacoeconomic assessments that are used in the decision-making process. While
the atypical antipsychotics have established efficacy in the overall treatment of
schizophrenia, they may differ in their effects on factors such as cognitive
function, overall quality of life, adverse events, and hospitalization status.
Each of these factors should be considered when weighing treatment options for an
individual patient.
PMID- 9766614
TI - Clinical development of atypical antipsychotics: research design and evaluation.
Collaborative Working Group on Clinical Trial Evaluations.
AB - Clinical trials support the efficacy and safety of new drugs on the market. They
provide the United States Food and Drug Administration with the information
needed to approve an Investigational New Drug application and are the basis for
package inserts provided by the manufacturers that guide clinicians in the use of
a new drug. Because clinical trials are vital to the effective and safe use of
new drugs, it is important to understand who participates in them, what questions
are answered by clinical trials, and what questions are raised. The reader who
asks the proper questions about issues such as methodology, affiliations of the
investigators, statistical analyses performed, location of study centers, and
study populations will derive the most information from the report of a clinical
trial.
PMID- 9766615
TI - Adverse effects of the atypical antipsychotics. Collaborative Working Group on
Clinical Trial Evaluations.
AB - Adverse effects of antipsychotics often lead to noncompliance. Thus, clinicians
should address patients' concerns about adverse effects and attempt to choose
medications that will improve their patients' quality of life as well as overall
health. The side effect profiles of the atypical antipsychotics are more
advantageous than those of the conventional neuroleptics. Conventional agents are
associated with unwanted central nervous system effects, including extrapyramidal
symptoms (EPS), tardive dyskinesia, sedation, and possible impairment of some
cognitive measures, as well as cardiac effects, orthostatic hypotension, hepatic
changes, anticholinergic side effects, sexual dysfunction, and weight gain. The
newer atypical agents have a lower risk of EPS, but are associated in varying
degrees with sedation, cardiovascular effects, anticholinergic effects, weight
gain, sexual dysfunction, hepatic effects, lowered seizure threshold (primarily
clozapine), and agranulocytosis (clozapine only). Since the incidence and
severity of specific adverse effects differ among the various atypicals, the
clinician should carefully consider which side effects are most likely to lead to
the individual's dissatisfaction and noncompliance before choosing an
antipsychotic for a particular patient.
PMID- 9766616
TI - Assessment of EPS and tardive dyskinesia in clinical trials. Collaborative
Working Group on Clinical Trial Evaluations.
AB - The incidence of acute extrapyramidal symptoms (EPS)--akathisia, dystonia, and
parkinsonism--associated with traditional antipsychotics varies, but most
researchers agree that neuroleptic-induced EPS occur in 50% to 75% of patients
who take conventional antipsychotics. Atypical antipsychotics were developed to
widen the therapeutic index and to reduce EPS. Although the mechanisms are
unclear, the risk of EPS is less with the novel antipsychotics than with
conventional drugs, and agents that produce low levels of acute EPS are likely to
produce less tardive dyskinesia. Nevertheless, clinicians should exercise caution
when comparing data from investigations of the novel antipsychotics and, until
long-term data become available, should administer the new drugs at doses below
the EPS-producing level.
PMID- 9766617
TI - Assessing the effects of atypical antipsychotics on negative symptoms.
Collaborative Working Group on Clinical Trial Evaluations.
AB - Attempts to clarify the domains of schizophrenia gained importance when the
atypical antipsychotics joined the armamentarium of schizophrenia treatments
because of evidence that these agents are superior to conventional antipsychotics
for the treatment of negative symptoms. Negative symptoms can be divided into 3
components: (1) deficit or primary enduring negative symptoms that may or may not
respond to treatment, (2) primary nonenduring negative symptoms, and (3)
secondary negative symptoms that are associated with positive symptoms,
extrapyramidal symptoms, depression, and environmental deprivation. The atypical
antipsychotics have generally been found to be more effective than conventional
antipsychotics against the totality of negative symptoms, but their effects on
specific components are still under study. Sophisticated statistical tools such
as path analysis have been used in investigations of the direct and indirect
effects of atypical antipsychotics on negative symptoms, but these tools have
limitations. Future study is needed to identify specific components of negative
symptoms that may respond preferentially to one or another of the atypical
antipsychotics.
PMID- 9766618
TI - Evaluating the effects of antipsychotics on cognition in schizophrenia.
Collaborative Working Group on Clinical Trial Evaluations.
AB - Cognitive deficits are an integral feature of schizophrenia and have a
deleterious effect on the ability of schizophrenic patients to work and function
in a social environment. Drugs that bring about substantial cognitive improvement
represent a major contribution in improving the quality of life in schizophrenia.
Recent studies have suggested that the atypical antipsychotics may be more useful
than conventional agents for improving cognition. There is evidence that scores
on neuropsychological assessments have improved after treatment with clozapine,
risperidone, and quetiapine. Future research is needed to characterize and
quantify the cognitive effects of the atypical antipsychotics.
PMID- 9766619
TI - Atypical antipsychotics for treatment of depression in schizophrenia and
affective disorders. Collaborative Working Group on Clinical Trial Evaluations.
AB - Depression in schizophrenia may be partially responsible for the increased
suicide rate in schizophrenic patients, which is more than 20 times higher than
that found in the general population. Affective disorders in patients with
schizophrenia are associated with a poor outcome, an increased risk of relapse,
and a high rate of suicide. There is evidence that atypical antipsychotics may
contribute to a reduction in suicidality, and although the new drugs are marketed
for the treatment of schizophrenia, their novel psychopharmacologic effects
suggest the possibility of other therapeutic applications. Recent studies of the
efficacy of the novel antipsychotics found that these agents may produce an
antidepressant effect in schizophrenia and may be used as either an adjunctive
medication or an alternative to mood stabilizers in patients with affective
disorders.
PMID- 9766620
TI - Treatment of special populations with the atypical antipsychotics. Collaborative
Working Group on Clinical Trial Evaluations.
AB - Atypical antipsychotics have become the treatment of choice for patients
experiencing a first episode of schizophrenia. In addition, they are often
prescribed for conditions such as bipolar disorder and dementia. While clinical
trials have not yet established the efficacy of the atypical antipsychotics for
these uses, a number of reports offer preliminary evidence that the atypical
antipsychotics may be beneficial for affective disorders, substance abuse
disorder, senile dementia, and pathologic aggression. Atypical agents may be
particularly effective and tolerable in elderly patients who are especially
susceptible to the adverse effects of conventional antipsychotic medication.
Lower dosages are more necessary for the elderly than for younger adults. Current
evidence suggests that clozapine is the most effective atypical antipsychotic for
neuroleptic-resistant patients. Risperidone, olanzapine, and quetiapine may also
be effective in a subset of these patients.
PMID- 9766621
TI - Adoptive immunotherapy of cancer using monocyte-derived macrophages: rationale,
current status, and perspectives.
AB - Adoptive transfer of host defense cells may be able to correct an otherwise
defective generation of competent immune cells in patients with cancer. Ex vivo
grown cytotoxic macrophages (MAC) able to recognize and destroy tumor cells but
not normal cells are effective in murine models of metastasizing tumors. After
the development of large-scale technology to generate MAC in vitro from blood
monocytes (MO), clinical trials in cancer patients have proven the feasibility
and safety of infusing >3 x 10(9) autologous MO-derived MAC activated by
interferon-gamma or lipopolysaccharide. Various modalities of adoptive
immunotherapy with human MAC have been realized: routes of application used were
intravenous, intraperitoneal, intrapleural, and through selective hepatic artery
perfusion. In addition, MAC have been generated from MO collected after granulyte
macrophage colony-stimulating factor treatment in vivo. Biodistribution studies
using 111indium-labeled cells have revealed localization of MAC to sites of bulk
tumor growth on regional infusion as well as to liver metastases on systemic
application. Malignant ascites disappeared in about 50% of patients after
intraperitoneal treatment, yet no other evidence of therapeutic efficacy of MAC
could be demonstrated. Further advances of adoptive transfer of MO-derived cells
are developed with emphasis on the generation of antigen-presenting cells primed
in vitro with tumor cells or specific peptides.
PMID- 9766622
TI - Nitric oxide synthase inhibition reduces muscle inflammation and necrosis in
modified muscle use.
AB - The objective of this study was to determine the role of nitric oxide in muscle
inflammation, fiber necrosis, and apoptosis of inflammatory cells in vivo. The
effects of nitric oxide synthase (NOS) inhibition on the concentrations of
neutrophils, ED1+ and ED2+ macrophages, apoptotic inflammatory cells, and
necrotic muscle fibers in rats subjected to 10 days of hindlimb unloading and 2
days of reloading were determined. Administration of NOS inhibitor N(omega)-nitro
L-arginine methyl ester (L-NAME) significantly reduced the concentrations of
neutrophils, ED1+ and ED2+ macrophages, and necrotic fibers in soleus muscle
relative to water-treated controls. The concentration of apoptotic inflammatory
cells was also significantly lower for L-NAME-treated animals compared with water
treated controls. However, the proportion of the inflammatory cell population
that was apoptotic did not differ between L-NAME-treated and control animals,
suggesting that L-NAME treatment did not decrease inflammatory cell populations
by increasing the frequency of apoptosis. Thus, nitric oxide or one of its
intermediates promotes muscle inflammation and fiber necrosis during modified
muscle use and plays no more than a minor role in the resolution of muscle
inflammation by inducing apoptosis of inflammatory cells.
PMID- 9766623
TI - Leukocyte trafficking in experimental autoimmune uveitis in vivo.
AB - Leukocyte trafficking from blood into tissue is a fundamental process in immune
surveillance and the immune response to stimuli. Experimental autoimmune uveitis
(EAU) is an animal model for posterior uveitis and is mediated by T lymphocytes
and macrophages that infiltrate the posterior segment of the eye. To analyze
leukocyte migration into retinal tissue during the course of EAU, labeled cells
were identified in vivo by scanning laser ophthalmoscopy and in retinal
flatmounts by confocal microscopy. Adhesion of blood leukocytes to retinal
endothelial cells in vivo was significantly raised 48 h before the appearance of
clinical disease, and this correlated with the increased expression of CD54 on
retinal vessels. Mitogen-activated spleen cells and CD4+ T cells only entered
into retinal tissue in animals with clinical disease and not naive recipients.
The disease status of the donor animal had no effect on leukocyte trafficking.
These results, which identify leukocyte-endothelial cell interactions in vivo,
suggest that the activation of the retinal endothelium is a prerequisite to
leukocyte adhesion and extravasation into ocular tissue during EAU.
PMID- 9766625
TI - Nitric oxide enhances the growth of U937 human leukemic cells through a
cyclooxygenase-mediated pathway.
AB - The mechanisms of exogenous nitric oxide (NO)-enhanced growth of the U937 human
myeloid leukemic cells were examined using sodium nitroprusside (SNP) as a NO
donor. Treatment with 0.1 mM SNP for 72 h caused a 45 +/- 2% increase in U937
cell growth with significantly increased S/G2+M-phase and decreased G0/G1-phase
of the cell cycle. The growth-enhancing effect of SNP was blocked by
indomethacin, a cyclooxygenase inhibitor, but not by H7, a broad spectrum kinase
inhibitor, or PD98059, a mitogen-activated protein kinase inhibitor. SNP
treatment resulted in a dose-dependent increase in prostaglandin E2 (PGE2)
production. Furthermore, the addition of exogenous PGE2 not only enhanced U937
cell growth but restored the indomethacin-inhibited mitogenic effect of SNP. We
suggest that NO can enhance cell growth through activating the cyclooxygenase
pathway and that PGE2 may be an effector molecule for NO-regulated cell
proliferation. Our data provide a mechanistic insight into the regulatory role of
NO in myelopoiesis.
PMID- 9766624
TI - Genetic and immunological parameters governing in vivo susceptibility/resistance
to retrovirally induced murine malignant histiocytosis.
AB - Malignant histiocytosis sarcoma virus (MHSV) arose as a recombinant of c-Harvey
ras murine sarcoma virus (Ha-MuSV) and Friend mink cell focus-forming virus (F
MCFV). It is a defective acute transforming retrovirus that, along with Friend
murine leukemia helper virus (F-MuLV), induces malignant histiocytosis (MH) in
susceptible adult mice. We have assessed the in vivo susceptibility to MHSV in
inbred homozygous, F1 hybrid, congenic, and recombinant inbred (RI) mice. We have
shown that: (1) in vivo resistance to MHSV is multigenic, regulated by MHC and
non-MHC genes in a different fashion than with F-MCFV, F-MuLV, or Ha-MuSV; (2)
using BXD RI mice, the resistance phenotype is linked with 95.8% probability to
two linked loci, Pmv-9 and Iapls3-14, on chromosome 13 (homologous to the area of
human chromosome 5 for which a chromosomal break point at position 5q35 is
associated with human MH); and (3) CD4+ T cells are critical for MHSV resistance.
PMID- 9766626
TI - Ionizing radiation potentiates the induction of nitric oxide synthase by IFN
gamma and/or LPS in murine macrophage cell lines: role of TNF-alpha.
AB - Macrophages are activated to become cytotoxic by a highly coordinated set of
cytokine signals. Ionizing radiation can mimic cytokine signals and lead to
enhanced states of activation. We tested the ability of gamma-radiation, alone
and with interferon-gamma (IFN-gamma) and/or lipopolysaccharide (LPS), to induce
nitric oxide (NO) production in J774.1 and RAW264.7 murine macrophages. NO was
induced weakly, moderately, or strongly by IFN-gamma alone, LPS alone, or IFN
gamma + LPS, respectively. Radiation alone (0.5-50 Gy) did not induce NO, but
enhanced NO production in a dose-dependent manner (0.5-5 Gy) when cells were
exposed to IFN-gamma or LPS 24 h post-irradiation. Immunoblots showed parallel
induction of nitric oxide synthase (NOS2). Application of anti-tumor necrosis
factor alpha (TNF-alpha) antibody before irradiation blocked induction of NO by
IFN-gamma. We conclude (1) that irradiated cells produce more NO in response to
either IFN-gamma or LPS and (2) that the increase is mediated by induction of TNF
alpha.
PMID- 9766627
TI - P-selectin and MAC-1 mediate monocyte rolling and adhesion to ECM-bound platelets
under flow conditions.
AB - Accumulation of monocyte-derived foam cells in focal areas of the atherosclerotic
(A.S.-) lesion is one of the key events in early atherogenesis. Using a flow
model for the damaged vessel wall, we examined the ability of ECM-bound platelets
to induce monocyte tethering and adhesion. Whereas ECM-proteins alone induced
monocyte adhesion only at low shear stresses (< 100 mPa), ECM-bound platelets
induced monocyte rolling and adhesion at shear stresses up to 240 mPa. Studies
with specific antibodies showed that monocyte adhesion to platelets was mainly
mediated by P-selectin and monocyte PSGL-1 (maximum inhibition 90%). beta2
Integrin blocking CD18 and CD11b antibodies partly inhibited the arrest of
rolling cells. Antibodies against other adhesion molecules such as LFA-1, PECAM
1, and beta1-integrins had no effect. Even sparsely adhered platelets
(approximately 10% coverage of the surface) already strongly supported monocyte
tethering. In conclusion, activated platelets present on ECM are a powerful
adhesive substrate for monocyte recruitment under flow conditions.
PMID- 9766628
TI - The identification and characterization of umbilical cord blood-derived human
basophils.
AB - Cross-linking allergen-specific immunoglobin E on human peripheral blood
basophils results in the release of histamine and other inflammatory mediators
that initiate allergy and asthma. The signaling pathways leading from IgE binding
to mediator release have not been well established, mainly due to the difficulty
in obtaining adequate numbers of highly purified basophils. It was the goal of
this study to easily obtain Fc epsilonRI-positive human basophils in high yield
and purity for studies of signal transduction pathways. We describe an in vitro
culture system in which pulsing normal human cord blood leukocytes with
interleukin-3 (IL-3) for 3-4 h followed by incubation in medium with fetal bovine
serum generates a cell population that is predominately Fc epsilonRI positive
between 14 and 28 days of culture. These cells resemble peripheral blood
basophils when examined by light and electron microscopy. Like normal blood
basophils, they express the integrins, CD11b, CD18, CD29, and CD49d. A majority
of the IL-3-pulsed cells also express a marker recognized by the basophil
specific antibody, 2D7. Fc epsilonRI cross-linking results in a time and dose
dependent release of histamine. Fc epsilonRI cross-linking also stimulates
protein-tyrosine phosphorylation, thought to be the first event leading to the
IgE-mediated activation of peripheral blood basophils. These studies establish
cord blood as an accessible source from which basophil-like cells can be
developed to examine Fc epsilonRI-mediated signal transduction.
PMID- 9766629
TI - Monocyte-derived dendritic cells have a phenotype comparable to that of dermal
dendritic cells and display ultrastructural granules distinct from Birbeck
granules.
AB - Most monocyte-derived dendritic cells (DC) display CD1a, like Langerhans cells
(LC) and some dermal DC, but their relationship with these skin DC remains
unclear. To address this issue, we studied the expression of different antigens
characteristic of skin DC and of monocyte/macrophages in CD1a+ and CD1a- monocyte
derived DC. Their phenotype indicated that they may be related to dermal DC
rather than to LC, i.e., they were all CD11b-positive, and 72% were Factor XIIIa
positive, but they did not express E-cadherin nor VLA-6. It is interesting that
CD1a+ and CD1a-cells showed intracytoplasmic granules that were different from LC
Birbeck granules. These phenotypical and ultrastructural features are comparable
to those of CD14-derived DC obtained from cord blood precursors [C. Caux et al.
J. Exp. Med. 184, 695-706]. These results show a close relationship between these
two in vitro models, which are both related to dermal DC.
PMID- 9766630
TI - The murine neutrophil-chemoattractant chemokines LIX, KC, and MIP-2 have distinct
induction kinetics, tissue distributions, and tissue-specific sensitivities to
glucocorticoid regulation in endotoxemia.
AB - Lipopolysaccharide-induced CXC chemokine (LIX) is a novel murine neutrophil
chemoattractant CXC chemokine cloned as a glucocorticoid-attenuated response
gene. We investigated LIX message expression in an acute endotoxemia model. LIX
message peaks later than KC or macrophage inflammatory protein-2 (MIP-2) and
remains elevated longer in almost all tissues. Induced LIX message expression in
heart is 5- to 6-fold greater than in lung and spleen, and 20-fold greater than
in liver. In contrast, KC expression is equal in heart, lung, and liver, whereas
MIP-2 expression is strongest in the lung. Glucocorticoid regulation of these
genes also differs. Endotoxemia-induced LIX message expression in the lung is
markedly enhanced in adrenalectomized mice and strongly attenuated by
dexamethasone, whereas lung KC and MIP-2 expression are unaffected by
glucocorticoids. It is surprising to note that endotoxemia-induced brain
expression of LIX (but not KC or MIP-2) is increased by dexamethasone. These
observations suggest that LIX may have biological roles distinct from KC and MIP
2.
PMID- 9766631
TI - Strong expression of CD134 (OX40), a member of the TNF receptor family, in a T
helper 2-type cytokine environment.
AB - CD134 (OX40) is involved in T cell costimulation and T cell-dependent antibody
production. We show strongly increased T cell expression of CD134 in a model of T
helper 2-mediated systemic autoimmunity, induced by HgCl2. Regulation of CD134
expression on CD4+ T cells was further studied in vitro, identifying CD134 as an
early marker of T cell activation. CD134 expression could be induced by
interleukin-4, but not by interferon-gamma or tumor necrosis factor-alpha.
Effects of interleukin-4 and of phorbol 12-myristate 13-acetate on CD134
expression could be blocked by the protein kinase inhibitor staurosporin.
Combination of these stimuli with ionomycin resulted in a strongly synergistic
increase of CD134 expression, which was blocked by the calcineurin-inhibitor
cyclosporin A. The results demonstrate the involvement of two synergistically
acting pathways in induction of CD134 expression. Furthermore, they suggest a
role for interleukin-4 in induction of CD134 expression in vivo.
PMID- 9766632
TI - Interleukin-8 priming of human neutrophils is not associated with persistently
altered calcium fluxes but is additive with lipopolysaccharide.
AB - Interleukin-8 (IL-8) priming was studied in neutrophils to examine its dependency
on altered calcium fluxes and for similarity to lipopolysaccharide (LPS). IL-8
caused a rapid rise in [Ca2+]i that returned to baseline values by 20 min. Peak
[Ca2+]i transients in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP)
were unaltered in IL-8-primed compared with unprimed cells. In comparison to LPS
and tumor necrosis factor (TNF), IL-8 was a much weaker priming agent as measured
by either O2- or H2O2 production. Despite their large disparity in potency, IL-8
and LPS printing were additive using fMLP, a receptor-dependent stimulator, and
synergistic using the post-receptor, protein kinase C activator, phorbol 12
myristate 13-acetate (PMA) to trigger the respiratory burst. In contrast, IL-8
and TNF priming were synergistic for fMLP (P = 0.05), but completely nonadditive
when PMA was used as the neutrophil stimulant (P = 0.05 for subadditivity). Thus,
lasting alterations in [Ca2+]i are not a necessary characteristic of IL-8-primed
cells. IL-8 and LPS appear to prime by non-overlapping pathways, whereas IL-8 and
TNF appear to share mechanisms distal to protein kinase C activation. IL-8 and
LPS may independently contribute to neutrophil-mediated host defense or injury by
priming through distinct pathways.
PMID- 9766633
TI - Interleukin-18/interferon-gamma-inducing factor, a novel cytokine, up-regulates
ICAM-1 (CD54) expression in KG-1 cells.
AB - Intercellular adhesion molecule-1 (ICAM-1, CD54) is a membrane glycoprotein and a
member of the immunoglobulin superfamily. It plays a central role in cell to cell
mediated immune responses and is a ligand for leukocyte function-associated
antigen-1 (LFA-1). We report here that a newly discovered cytokine, interferon
gamma-inducing factor (IGIF) [H. Okamura et al. (1995) Nature 378, 88] recently
proposed to be designated as IL-18, selectively up-regulates ICAM-1 expression in
KG-1 cells, a human myelomonocytic cell line, in which IL-18 also enhances
interferon-gamma production. IL-18 induced heterotypic aggregation between KG-1
and Peer T cells, which was blocked by anti-ICAM-1 and/or LFA-1 antibodies. Anti
interferon-gamma antibody did not block the IL-18-induced up-regulation of ICAM-1
on KG-1 cells. These results thus show that IGIF/IL-18, enhances ICAM-1
expression in KG-1 cells in an interferon-gamma-independent pathway, up-regulates
ICAM-1 functions, and that IL-18 might play a potential role in immunoregulation
by mediating immune cell infiltration into the tissues.
PMID- 9766634
TI - TNF and IL-6 mediate MIP-1alpha expression in bleomycin-induced lung injury.
AB - Previously, macrophage inflammatory protein-1alpha (MIP-1alpha), a member of the
C-C chemokine family, has been implicated in bleomycin-induced pulmonary
fibrosis, a model of the human disease idiopathic pulmonary fibrosis.
Neutralization of MIP-1alpha protein with anti-MIP-1alpha antibodies
significantly attenuated both mononuclear phagocyte recruitment and pulmonary
fibrosis in bleomycin-challenged CBA/J mice. However, the specific stimuli for
MIP-1alpha expression in the bleomycin-induced lesion have not been
characterized. In this report, two mediators of the inflammatory response to
bleomycin, tumor necrosis factor (TNF) and interleukin-6 (IL-6), were evaluated
as putative stimuli for MIP-1alpha expression after bleomycin challenge in CBA/J
mice. Elevated levels of bioactive TNF and IL-6 were detected in bronchoalveolar
lavage (BAL) fluid and lung homogenates from bleomycin-treated CBA/J mice at time
points post-bleomycin challenge, which precede MIP-1alpha protein expression.
Treatment of bleomycin-challenged mice with soluble TNF receptor (sTNFr) or anti
IL-6 antibodies significantly decreased MIP-1alpha protein expression in the
lungs. Furthermore, normal alveolar macrophages secreted elevated levels of MIP
1alpha protein in response to treatment with TNF plus IL-6 or bleomycin plus IL
6, but not TNF, bleomycin, or IL-6 alone. Finally, leukocytes recovered from the
BAL fluid of bleomycin-challenged mice secreted higher levels of MIP-1alpha
protein, compared to controls, when treated with TNF alone. Based on the data
presented here, we propose that TNF and IL-6 are part of a cytokine network that
modulates MIP-1alpha protein expression in the profibrotic inflammatory lesion
during the response to intratracheal bleomycin challenge.
PMID- 9766635
TI - Activation of mitogen-activated protein kinase cascades during priming of human
neutrophils by TNF-alpha and GM-CSF.
AB - The signal transduction pathways activated by tumor necrosis factor alpha (TNF
alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) that lead to
priming of polymorphonuclear leukocytes (PMNs) are unknown. The hypotheses that
these cytokines stimulate multiple mitogen-activated protein kinase (MAPK)
cascades, including extracellular signal-regulated kinases (ERKs), c-Jun amino
terminal kinases (JNKs), and p38 MAPK, and that these MAPKs participate in
priming of human PMNs were examined. TNF-alpha stimulated a dose-dependent
increase in ERK and p38 MAPK activities that was maximal at 10 min. JNKs were not
stimulated by TNF-alpha or GM-CSF. GM-CSF stimulated ERK activity comparable to
that of TNF-alpha, but GM-CSF was a less potent stimulus of p38 MAPK activity.
The tyrosine kinase inhibitor, genistein, inhibited ERK and p38 MAPK stimulation
by both cytokines. The phosphatidylinositol 3-kinase inhibitor, wortmannin,
attenuated stimulation of ERKs and p38 MAPK by GM-CSF, but not TNF-alpha. GM-CSF,
but not TNF-alpha, stimulated wortmannin-sensitive activation of Raf-1. TNF-alpha
and GM-CSF priming of superoxide release stimulated by N-formyl-methionyl-leucyl
phenylalanine was significantly attenuated by the MEK inhibitor, PD098059, and
the p38 MAPK inhibitor, SB203580. Incubation with both MAPK inhibitors produced
an additive effect. Our data suggest that TNF-alpha and GM-CSF activate ERKs and
p38 MAPK by different signal transduction pathways. Both ERK and p38 MAPK
cascades contribute to the ability of TNF-alpha and GM-CSF to prime the
respiratory burst response in human PMNs.
PMID- 9766636
TI - The IFN-inducible nucleoprotein IFI 16 is expressed in cells of the monocyte
lineage, but is rapidly and markedly down-regulated in other myeloid precursor
populations.
AB - IFI 16 is an interferon-inducible nucleoprotein expressed by human monocytes. IFI
16 and a related mouse protein, p202, control cellular proliferation by binding
and modulating the functions of cell cycle regulatory factors including p53 and
the retinoblastoma gene product, pRb. In this study, we examined IFI 16
expression in myeloid precursor cells cultured in vitro in colony-forming assays
using granulocyte (G-) and granulocyte-macrophage (GM-) colony-stimulating factor
(CSF). IFI 16 was expressed in 100% of CD34+ cells isolated from human bone
marrow. When the CD34+ cells were induced to differentiate, two sub-populations
of cells were identified by two-color cytofluorography: the CD14+ (monocytoid)
cells all expressed IFI 16, whereas the CD14- (polymorphonuclear precursor) cells
did not. The strongest expression of IFI 16 was in the cells staining brightest
for CD14, whereas depletion of CD14+ monocytoid cells from mixed
monocytic/granulocytic cultures largely abolished IFI 16-stained cells.
Furthermore, in eight independent colony-forming assays, the number of IFI 16+
cells correlated closely with the numbers of monocyte precursors identified
morphologically (R2 = 0.99), but was unrelated to the numbers of myelocytes,
promyelocytes, and metamyelocytes; nor was IFI 16 expressed by erythroid or
eosinophil precursors. We conclude that IFI 16 is expressed in CD34+ and
monocytoid daughter cells, but is rapidly and markedly down-regulated at the
corresponding stages of polymorphonuclear and erythroid development. This
differential expression of IFI 16 in myeloid precursor subpopulations and its
perceived molecular properties are consistent with a possible role in regulating
myelopoiesis.
PMID- 9766638
TI - Pathways for eosinophil lipid body induction: differing signal transduction in
cells from normal and hypereosinophilic subjects.
AB - Although lipid bodies, inducible cytoplasmic inclusions active in arachidonic
acid metabolism, are abundant in activated leukocytes, including eosinophils,
mechanisms for eosinophil lipid body formation are not certain. Eosinophils from
hypereosinophilic syndrome (HES) donors contained about twice (approximately
18/cell) as many lipid bodies as eosinophils froin normal donors (approximately
10/cell). By immunocytochemistry both 5- and 15-lipoxygenases were localized at
lipid bodies in HES eosinophils. Platelet-activating factor (PAF) induced rapid,
receptor-mediated increases in lipid bodies in normal and HES eosinophils.
Protein kinase C (PKC) inhibitors, chelerythrine and calphostin C, inhibited PAF
induced lipid body formation partially in normal and HES eosinophils. In HES, but
not normal, eosinophils, PAF-induced lipid body formation was completely blocked
by two tyrosine kinase inhibitors, herbimycin A and genistein, which were not
acting on 5-lipoxygenase because they also blocked 5-HETE-induced lipid body
formation in HES, and not normal, eosinophils. After 24 h culture with eosinophil
growth factor cytokines [interleukin (IL)-3, IL-5, and granulocyte-macrophage
colony-stimulating factor (GM-CSF) or GM-CSF alone but not IL-5 or IL-3 alone],
normal eosinophils were induced to exhibit an HES-like phenotype, including
increased lipid body numbers and tyrosine kinase-dependent signaling for PAF
induced lipid body formation. Thus, signal transduction mechanisms involved in
PAF-induced lipid body formation in eosinophils can be differentially recruited.
Tyrosine kinase-dependent signaling is not involved in normal eosinophils, but is
active in HES eosinophils and in normal eosinophils cultured with GM-CSF. PKC-
and tyrosine kinase-dependent pathways are involved in the formation of
eosinophil lipid bodies, which may facilitate enhanced synthesis of lipoxygenase
derived eicosanoids.
PMID- 9766639
TI - Translational research: walking the bridge between idea and cure--seventeenth
Bruce F. Cain Memorial Award lecture.
AB - Advances in the understanding of normal and malignant cell biology are allowing
the development of biologically targeted drugs directed at specific differences
between host and tumor. The array of potential new targets is vast, but drugs
currently in development are targeted at cell-cycle regulators, growth factors
and their receptors, signal transduction intermediates, angiogenesis, and the
mechanisms that mediate apoptosis and DNA repair. Recent results raise the
possibility that novel biologically targeted agents, perhaps in combination with
traditional cytotoxic agents, may finally cure cancer. However, the development
of a biologically targeted drug raises unique challenges in the design of
clinical trials to demonstrate its efficacy, and despite the promising
preclinical data that exist for most of the agents in development, the clinical
trial remains the critical, final step across the bridge from basic research to
clinical application. In this review, we discuss some of the challenges in the
clinical development of biologically targeted agents and the implications for
clinical trial design.
PMID- 9766637
TI - Role of the mitogen-activated protein kinases and tyrosine kinases during
leukotriene B4-induced eosinophil activation.
AB - Exposure of guinea-pig eosinophils to leukotriene B4 (LTB4; 1 microM) resulted in
a rapid generation of H2O2 (index of NADPH oxidase activation), stimulated
[3H]arachidonic acid (AA) release (index of phospholipase A2 activity), and
promoted CD18-dependent homotypic aggregation. Under similar conditions, LTB4 (1
microM) induced a rapid activation of extracellular-regulated kinases-1 and 2
(ERK-1/2) but not c-jun N-terminal kinases 46 and 54 (JNK-46/54) or p38 mitogen
activated protein kinase (p38 MAP kinase). To examine the role of ERK-1/2 in the
mechanism of eosinophil activation, a selective inhibitor of MAP kinase kinase
1/2 (MEK-1/2), PD098059, was employed. However, PD 098059 at concentrations that
attenuated ERK-1/2 activation had no significant affect on eosinophil activation.
In contrast, a role for tyrosine kinases in LTB4-induced eosinophil activation
was suggested by studies with the tyrosine kinase inhibitors, herbimycin A and
lavendustin A. However, the results of those experiments implied divergent
pathways for the control of eosinophil responses because the inhibitors were more
effective at attenuating H2O2 generation than [3H]AA release, and had little
effect on homotypic aggregation.
PMID- 9766640
TI - Widespread skeletal metastatic potential of human lung cancer revealed by green
fluorescent protein expression.
AB - To understand the skeletal metastatic pattern of non-small cell lung cancer, we
developed a stable high-expression green fluorescent protein (GFP) transductant
of human lung cancer cell line H460 (H460-GFP). The GFP-expressing lung cancer
was visualized to metastasize widely throughout the skeleton when implanted
orthotopically in nude mice. H460 was transduced with the pLEIN retroviral
expression vector containing the enhanced GFP and the neomycin (G418) resistance
gene. A stable high GFP-expressing clone was selected in vitro using 800
microg/ml G418. Stable high-level expression of GFP was maintained in s.c.
growing tumors formed after injecting H460-GFP cells in nude mice. To use H460
GFP for visualization of metastasis, fragments of s.c.-growing H460-GFP tumors
were implanted by surgical orthotopic implantation in the left lung of nude mice.
Subsequent micrometastases were visualized by GFP fluorescence in the
contralateral lung, plural membrane, and widely throughout the skeletal system
including the skull, vertebra, femur, tibia, pelvis, and bone marrow of the femur
and tibia. The use of GFP-expressing H460 cells transplanted by surgical
orthotopic implantation revealed the extensive metastatic potential of lung
cancer in particular to widely disseminated sites throughout the skeleton. This
new metastatic model can play a critical role in the study of the mechanism of
skeletal and other metastasis in lung cancer and in screening of therapeutics
that prevent or reverse this process.
PMID- 9766641
TI - Loss of chromosome 18q is an early event in pancreatic ductal tumorigenesis.
AB - Cytogenetic and molecular studies demonstrated that pancreatic cancer frequently
shows specific chromosomal abnormalities, such as losses of 9p, 17p, and 18q, and
gains of 8q and 20q. We have analyzed alterations in the copy number of specific
chromosomal regions in cells from the pancreatic juices of 32 patients with
various pancreatic disorders by fluorescence in situ hybridization (FISH)
technique to pursue the possible clinical use of early diagnosis of pancreatic
cancer. None of the chromosomal abnormalities were found in 13 specimens from
individuals who had no neoplastic lesions. On the other hand, 12 specimens (63%)
derived from the remaining 19 patients who had neoplastic lesions showed at least
one chromosomal abnormality. Ten of these specimens were from pancreatic cancer
patients; 7 cases (70%) showed chromosomal abnormalities. All but one of the 12
tumors with chromosomal abnormalities had loss of 18q. Furthermore, we detected a
tumor in one patient in whom the routine cytological method and endoscopic
retrograde chorangiopancreatography found nothing. Based on the results by FISH,
we performed endoscopic ultrasonography and found a small serous cystadenoma in
this patient. These results indicate that: (a) FISH analysis of cells from
pancreatic juices obtained during endoscopic retrograde chorangiopancreatography
is quite useful for detecting pancreatic ductal tumors; and (b) loss of
chromosome 18q is one of the early genetic changes that provide very useful
information in diagnosing pancreatic neoplasias.
PMID- 9766642
TI - Mutational analysis of the transforming growth factor beta receptor type II gene
in human ovarian carcinoma.
AB - In the present study, we evaluated a series of sporadic ovarian carcinomas for
mutations within the entire coding region of TbetaR-II. Using reverse
transcription-PCR and "Cold" single-strand conformational polymorphism analysis,
6 of 24 samples (25%) were found to contain code-altering mutations in TbetaR-II:
(a) four mutations resulting in amino acid substitutions in the highly conserved
serine/threonine kinase domain; (b) one mutation resulting in a conservative
amino acid change in the transmembrane domain; and (c) a 1-bp insertion in the
polyadenylic acid microsatellite region resulting in a reading frameshift. In
addition, six cases (25%) exhibited a common bp substitution (C-->T at nucleotide
1322) in both tumor and patient-matched normal tissues. This is the first report
of such TbetaR-II mutations in primary human ovarian carcinomas.
Immunohistochemical analysis demonstrated a loss of expression of TbetaR-II in 5
of 22 available tumors (23%; 4 of which also had mutations in the coding region)
and decreased expression of TbetaR-II in 10 of 22 available tumors (44%; 1 of
which had a mutation in the coding region). Thus, the loss or decreased
expression of TbetaR-II seems to be a common event in sporadic ovarian
carcinomas, and mutational inactivation, due to either frameshift mutations in
the polyadenylic acid microsatellite region or point mutations in conserved
functional domains, is one mechanism by which this occurs.
PMID- 9766643
TI - A novel candidate oncogene, MCT-1, is involved in cell cycle progression.
AB - Using the arbitrarily primed-PCR (AP-PCR) assay to detect genetic abnormalities
that occur in a panel of lymphoid cell lines, we identified an amplified stretch
of genomic DNA that contained a putative open reading frame. Northern blot
analysis with this genomic clone revealed widespread low level expression in
normal human tissue. The full cDNA sequence was obtained with no significant
homology to any known genes in the genome database. We termed this novel gene
with multiple copies in a T-cell malignancy as MCT-1. MCT-1 was localized to the
long arm of chromosome Xq22-24 by flourescence in situ hybridization analysis.
Although there was no significant homology at the primary sequence level, there
was a limited degree of amino acid homology with a domain of cyclin H that
appears to specify protein-protein complexes. This relationship between MCT-1 and
cyclin H implied a potential role for MCT-1 in cell cycle regulation.
Overexpression of MCT-1 increased the proliferative rate of cells by decreasing
the length of the G1 phase without a reciprocal increase in the S and G2-M
phases. Recent work has established the role of cell cycle regulatory molecules
in the development of certain human malignancies. Therefore, we investigated the
transforming ability of MCT-1 overexpression using soft agar growth assays and
demonstrated that only MCT-1-overexpressing cells were able to establish
colonies. Taken together, MCT-1 is a novel candidate oncogene with homology to a
protein-protein binding domain of cyclin H.
PMID- 9766645
TI - NS398, a selective cyclooxygenase-2 inhibitor, induces apoptosis and down
regulates bcl-2 expression in LNCaP cells.
AB - Cyclooxygenase (COX)-2, an inducible enzyme that catalyzes the formation of
prostaglandins and other eicosanoids from arachidonic acid, is constitutively
expressed in LNCaP human prostate cancer cell line. To evaluate the potential
role of COX-2 in prostate cancer, LNCaP cells were treated with NS398, a
selective COX-2 inhibitor, and the effects on cell viability and apoptosis were
determined. NS398 treatment induced apoptosis in LNCaP cells in a time- and dose
dependent fashion. Treatment with 100 microM NS398 caused a down-regulation in
bcl-2 protein expression, followed by chromatin condensation, chromosomal DNA
fragmentation, and changes in nuclear morphology detected by 4,6-diamidino-2
phenylindole staining, DNA fragmentation assay, and terminal deoxynucleotidyl
transferase-mediated UTP-biotin nick end-labeling assay. In contrast, NS398
treatment had no effect on either cell viability or nuclear function and
morphology in human fetal prostate fibroblasts. These results demonstrate that
NS398 induces apoptosis in LNCaP cells but not in human fetal prostate
fibroblasts, and that this induction is associated with a decreased level of bcl
2 protein.
PMID- 9766644
TI - RIZ1, but not the alternative RIZ2 product of the same gene, is underexpressed in
breast cancer, and forced RIZ1 expression causes G2-M cell cycle arrest and/or
apoptosis.
AB - The retinoblastoma protein-interacting zinc finger gene RIZ maps to the distal
short arm of human chromosome 1 (1p36), a region thought to harbor tumor
suppressor genes for a variety of human cancers including breast cancer. The RIZ
gene normally produces two protein products of different length, RIZ1 and RIZ2.
RIZ2 is generated by an internal promoter and lacks an NH2-terminal motif of
RIZ1, the PR domain conserved in a subfamily of zinc finger genes that function
as negative regulators of tumorigenesis. We have here studied whether the RIZ
gene may play a role in human neoplasia. We found that expression of RIZ1 is
commonly decreased or at undetectable levels in breast cancer tissues and cell
lines. Decreased RIZ1 expression was also found in other tumor types including
neuroblastoma and lung cancer. Remarkably, RIZ2 is normally expressed in all
cases examined, suggesting that the abnormality observed for RIZ1 is specific.
Forced RIZ1 expression in breast cancer cells caused cell cycle arrest in G2-M
and/or programmed cell death. These observations suggest an exclusive negative
selection for RIZ1 but not RIZ2 in breast cancer and a role for RIZ1 in tumor
suppression.
PMID- 9766647
TI - Development of Helicobacter pylori-induced gastric carcinoma in Mongolian
gerbils.
AB - Helicobacter pylori is classified by IARC/WHO as a definite human gastric
carcinogen, despite "inadequate experimental evidence." To obtain direct evidence
concerning this relationship, we investigated the histopathological findings of
gastric mucosa using a model of H. pylori infection in Mongolian gerbils. The
animals were challenged p.o. with H. pylori ATCC-43504 and sacrificed at 6, 12,
and 18 months after inoculation for histological examination. All inoculated
animals were infected with H. pylori. Severe infiltration of the lamina propria
by polymorphonuclear and mononuclear cells appeared in the lesser curvature of
the antrum, with an increase in epithelial cell proliferation, and the
infiltration extended to the body. Atrophic gastritis and focal intestinal
metaplasia also appeared in the lesser curvature of the antral mucosa at 6 months
after inoculation. Intestinal metaplasia became severe, with dysplasia, after
that. At 18 months after H. pylori inoculation, two of five infected animals
showed three well-differentiated gastric cancers. The uninfected control animals
showed no abnormal findings throughout the entire observation period. Here, it
was confirmed that H. pylori infection alone causes gastric cancer in an animal
model.
PMID- 9766646
TI - Enhanced expression of the insulin receptor substrate-2 docking protein in human
pancreatic cancer.
AB - Insulin receptor substrate-2 (IRS-2) is a multisite docking protein implicated in
mitogenic signaling after activation of the insulin and insulin-like growth
factor (IGF)-I receptors. In the present study, we characterized IRS-2 expression
and function in human pancreatic cancer. IRS-2 mRNA and protein were expressed in
ASPC-1 and COLO-357 human pancreatic cancer cell lines. Insulin, IGF-I, and IGF
II enhanced the growth of both cell lines, stimulated tyrosine phosphorylation of
IRS-2, and increased IRS-2-associated phosphatidylinositol (PI) 3-kinase
activity. The mitogenic effects of insulin, IGF-I, and IGF-II were markedly
attenuated by the PI 3-kinase inhibitor LY 294002. Northern blot analysis of
total RNA extracted from normal and cancerous tissues revealed that IRS-2 mRNA
levels were increased in the cancer tissues (P = 0.032). In the normal pancreas,
IRS-2 immunoreactivity was present at low levels in some ductal and acinar cells
and at moderate levels in a heterogeneous pattern in all of the endocrine islets.
In the pancreatic cancers, IRS-2 was abundant in the ductal-like cancer cells.
These findings indicate that IRS-2 is overexpressed in human pancreatic cancer
and suggest that it may contribute to enhanced mitogenic signaling via the PI 3
kinase pathway, thereby leading to excessive growth stimulation in this
malignancy.
PMID- 9766648
TI - Chromosomal amplification is associated with cisplatin resistance of human male
germ cell tumors.
AB - Chemotherapy resistance of tumors is an important biological and clinical
problem. Studies from many tumor types have indicated that resistance may be
based on multiple genetic pathways. Human male germa cell tumors (GCTs) are an
especially good model system to study the genetic basis of tumor sensitivity and
resistance to chemotherapy. GCTs are exquisitely sensitive to treatment with DNA
damaging drugs such as cisplatin, rarely exhibit TP53 gene mutations, express
normal p53 protein, and undergo p53-mediated apoptosis upon drug treatment. A
small proportion of tumors (20-30% of metastatic lesions) escape the apoptotic
response and result in treatment resistance. We have recently shown (J.
Houldsworth, et al., Oncogene, 16: 2345-2359, 1998) that in a subset of such
tumors, resistance is linked to TP53 gene mutations. In a further search for
genetic mechanisms underlying resistance, we subjected a panel of 17 tumors from
relapse-free patients (sensitive) and 17 chemotherapy-resistant tumors to
comparative genomic hybridization analysis to identify possible amplified regions
(implying amplified/overexpressed genes) associated with resistance. With the
exception of 12p11.2-12, high level amplification was not detected in any of the
sensitive tumors. We have identified eight amplified regions (1q31-32, 2p23-24,
7q21, 7q31, 9q22, 9q32-34, 15q23-24, and 20q11.2-12) in five resistant tumors,
which suggests that chromosomal and, hence, gene amplification may comprise a
pathway to drug resistance. Identification of amplified/overexpressed genes at
these sites may elucidate new genetic pathways of chemotherapy resistance in GCTs
and possibly also in other tumors.
PMID- 9766649
TI - The estrogen receptor variant lacking exon 5 has dominant negative activity in
the human breast epithelial cell line HMT-3522S1.
AB - The estrogen receptor variant lacking exon 5 (ERdeltaE5) encodes a truncated
protein that lacks the hormone-binding domain and has been suggested to be
responsible for the estrogen-independent growth of human breast tumors and
resistance to antiestrogen therapy. The biological function of the ERdeltaE5 in
human breast epithelial cells has been studied by transient transfection of HMT
3522S1 cells with wild-type (wt) estrogen receptor (ER) and ERdeltaE5. A 10-fold
higher expression of ERdeltaE5 mRNA compared to that of wt ER mRNA was found.
However, the expression of ERdeltaE5 protein was significantly lower than the
expression of wt ER protein. The ERdeltaE5 was unable to activate the
transcription of an estrogen-responsive reporter gene in the absence as well as
in the presence of estrogen. The ERdeltaE5 disclosed a dominant negative activity
when expressed together with wt ER. These data indicate that the biological
significance of ERdeltaE5 in human breast cancer is dubious.
PMID- 9766650
TI - NUP98-HOXD13 gene fusion in therapy-related acute myelogenous leukemia.
AB - A novel chromosomal translocation, t(2;11)(q31;p15), was identified in a patient
with therapy-related acute myelogenous leukemia (t-AML). Fluorescence in situ
hybridization experiments mapped the breakpoint near NUP98; Southern blot
analysis demonstrated that the nucleoporin gene NUP98 was disrupted by this
translocation. We used rapid amplification of cDNA ends to identify a chimeric
mRNA. An in-frame, chimeric mRNA that fused NUP98 sequences to the homeobox gene
HOXD13 was cloned; the predicted fusion protein contains both the GLFG repeats
from NUP98 as well as the homeodomain from HOXD13. The NUP98-HOXD13 fusion is
structurally similar to the NUP98-HOXA9 fusion previously identified in patients
with AML, leading to the speculation that NUP98-homeobox gene fusions may be
oncogenic. Moreover, this report, along with a recent study that demonstrated
NUP98-DDX10 fusions in patients with t-AML, raises the possibility that NUP98 may
be a previously unsuspected target for chromosomal translocations in patients
with t-AML.
PMID- 9766651
TI - Genomic alterations in fallopian tube carcinoma: comparison to serous uterine and
ovarian carcinomas reveals similarity suggesting likeness in molecular
pathogenesis.
AB - Serous carcinomas of the fallopian tube, uterus, and ovary resemble each other
both histologically and in clinical behavior. Comparative genomic hybridization
was performed on 20 primary fallopian tube carcinoma specimens to find regions of
the genome involved in tubal carcinogenesis and to compare the genomic
alterations with those previously detected in serous ovarian and uterine
carcinomas. The most frequent changes detected in fallopian tube carcinoma were
gains at 3q (70%) and 8q (75%), with high-level amplifications in several cases.
Other common gains occurred at 1q, 5p, 7q, 12p, and 20q. The most frequent losses
were found at 18q, 8p, 4q, and 5q. The frequency and the pattern of chromosomal
changes detected in tubal carcinoma were strikingly similar to those observed in
serous ovarian and uterine carcinomas, suggesting common molecular pathogenesis.
PMID- 9766652
TI - p53 is involved in but not required for ionizing radiation-induced caspase-3
activation and apoptosis in human lymphoblast cell lines.
AB - The caspase-3 has been shown to be involved in mediating apoptosis induced by
different stimuli. However, it is still unclear whether p53 is required for the
ionizing radiation (IR)-induced caspase-3 activation. In the present study, we
examined IR-induced apoptosis in three closely related human lymphoblast cell
lines that differ in p53 status. Irradiation of TK6 cells (wild-type p53) with 4
Gy gamma-rays resulted in rapid apoptosis, whereas the apoptotic response was
delayed and reduced in WTK1 cells (mutant p53) and the TK6 derivative line
expressing HPV16 E6 (abrogated p53). The differential apoptotic responses in
these cell lines correlated with caspase-3 activation. IR induced an early as
well as a late phase of caspase-3 activation in TK6 but only a delayed onset in
WTK1 and TK6-E6-5E cells. The early phase of caspase-3 activation coincided with
an elevation of p53 and bax protein levels. Pretreatment of all three cell lines
with a caspases inhibitor z-VAD-FMK inhibited apoptosis. These results suggest
that IR-induced apoptosis is mediated by a mechanism involving the caspase-3
cascade, which is shared by both p53-dependent and -independent pathways. The
activation of caspase-3 by IR may thus engage at least two separate mechanisms,
one through the regulation of the bcl-2 family members by p53, whereas the other
yet-to-be-identified one involves neither p53 nor bax.
PMID- 9766653
TI - Tumor suppressor proteins as regulators of cell differentiation.
AB - The products of the tumor suppressor genes are considered to function as specific
inhibitors of tumor cell growth. In this communication, we present evidence to
show that these proteins inhibit tumor cell proliferation by participating in the
activation of tumor cell differentiation. The ML-1 human myeloblastic leukemia
cells used in this study proliferate when treated with insulin-like growth factor
I and transferrin but differentiate to monocytes when exposed to tumor necrosis
factor alpha or transforming growth factor beta1, or to macrophage-like cells
when treated with both these cytokines. Initiation of proliferation but not of
differentiation was followed by a 20- to 25-fold increase in the nuclear level of
the DNA polymerase-associated processivity factor PCNA and of the proliferation
specific transcription factor E2F1. In contrast, induction of differentiation but
not of proliferation was followed by a 25- to 30-fold increase in the nuclear
level of the tumor suppressor proteins p53 (wild type), pRb, and p130/Rb2 and of
the p53-dependent cyclin kinase inhibitor p21/Cip1. p53 and p21/Cip1,
respectively, inhibit the expression and activation of PCNA, whereas p130 and
pRb, respectively, inhibit the expression and activation of E2F1. As a result, G1
S-associated DNA and mRNA synthesis is inhibited, growth uncoupled from
differentiation, and maturation enabled to proceed. Where this function of the
tumor suppressor proteins is impaired, the capacity for differentiation is lost,
which leads to the sustained proliferation that is characteristic of the cancer
cell.
PMID- 9766654
TI - Neuropeptides induce Mr 92,000 type IV collagenase (matrix metalloprotease-9)
activity in human prostate cancer cell lines.
AB - The type IV collagenases matrix metalloprotease (MMP)-2 and MMP-9 are linked with
a wide array of biological activities, including tumor invasion, metastasis, and
angiogenesis. Here, we report that neuropeptide hormones, which are present in
prostatic adenocarcinomas, can stimulate secreted activity of MMP-9 in human
prostate cancer cell lines. Northern blotting analyses demonstrated that
neuropeptide stimulation lead to elevated mRNA levels of MMP-9 but not MMP-2.
Further assays of MMP-9 promoter activation and a nuclear run-off indicated that
neuropeptide induction of MMP-9 expression occurs at the level of transcription.
These data indicate that neuropeptides can regulate MMP activity, which, in turn,
could facilitate prostate cancer progression.
PMID- 9766655
TI - Role of E2F-1 in chemosensitivity.
AB - The E2F family of transcription factors, in partnership with DP proteins, is
thought to regulate transcription of genes that encode protein products that are
required for DNA synthesis, which include important cancer chemotherapeutic
targets such as thymidylate synthase and dihydrofolate reductase. This study was
conducted to investigate the effects of overexpression of human E2F-1 cDNA on
chemosensitivity in a human fibrosarcoma cell line, HT-1080. The E2F-1
overexpressing HT-1080 cells had a shorter doubling time both in vitro and in
vivo. Associated with an up-regulation of TS, E2F-1-transfected cells were more
resistant to 5-fluorouracil than were untransfected cells. These E2F-1
transfectants, although resistant to fluoropyrimidines and serum deprivation,
were more sensitive to etoposide, doxorubicin, and SN38 (the active metabolite of
irinotecan) but not to Taxol.
PMID- 9766656
TI - Activation of JNK and p38 but not ERK MAP kinases in human skin cells by 5
aminolevulinate-photodynamic therapy.
AB - 5-Aminolevulinate (ALA) photodynamic therapy (PDT) is being used clinically for
the treatment of skin cancers. ALA is applied as a precursor of porphyrins
serving as endogenous photosensitizers. Irradiation of HaCaT cells preincubated
with 1 mM ALA for 24 h with red light of 570-750 nm at a dose of 4.5 J/cm2 leads
to a 6-fold elevation of cellular c-Jun N-terminal kinase activity;
phosphorylation of p38 mitogen-activated protein kinase (MAPK) is enhanced to a
similar extent. In contrast, neither activation nor increased phosphorylation of
the extracellular stimulus-regulated kinase MAPKs is detected. p38 is also
phosphorylated by ALA-PDT in the human melanoma cell lines Bro and SkMel-23,
applying doses that lead to 80-95% cell death after 24 h. Hence, the effects of
ALA-PDT on MAPKs are similar to stresses like UV irradiation or exposure to
hydrogen peroxide with respect to activation of JNK and p38 MAPKs. They are
different, however, in that extracellular stimulus-regulated kinase activity is
not raised by ALA-PDT. Of the 830 pmol porphyrins/mg protein that were present at
24 h in HaCaT cells, 99 pmol/mg were intracellular. When extracellular porphyrins
had been removed by washing, p38 responses were retained. Thus, intracellular
porphyrins synthesized from ALA are sufficient to elicit activation of p38 on
photosensitization.
PMID- 9766657
TI - Elevation of alpha2-->6 sialyltransferase and alpha1-->2 fucosyltransferase
activities in human choriocarcinoma.
AB - Structures of N-linked sugar chains are species and tissue specific and change in
the course of tumorigenesis. Sialyl linkages of human placental glycoproteins are
exclusively Neu5Ac alpha2-->3Gal, whereas Fuc alpha1-->2Gal and Neu5Ac alpha2-
>6Gal residues are expressed in human chorionic gonadotropin and alkaline
phosphatase, which are produced in human choriocarcinoma JEG-3 and BeWo cells. In
the present study, to elucidate the enzymological and molecular biological basis
of the structural changes that occur in the course of tumorigenesis, alpha1-->2
fucosyltransferase, alpha2-->3 and alpha2-->6 sialyltransferase activities, and
the expression levels of the corresponding mRNAs were measured. The alpha2-->3
sialyltransferase activity did not change as a result of tumorigenesis; however,
the alpha2-->6 siayltransferase activity and alpha1-->2 fucosyltransferase
activity in JEG-3 and BeWo cells increased to levels several times higher than
those in placenta Competitive PCR analysis showed that the expression levels of
mRNA encoding alpha1-->2 fucosyltransferase and mRNA encoding alpha2-->6
sialyltransferase increased significantly as a result of tumorigenesis,
indicating that such structural changes are regulated at the level of
transcription of these glycosyltransferase genes.
PMID- 9766658
TI - Immunohistochemical demonstration of carcinogen-DNA adducts in tissues of rats
given 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP): detection in
paraffin-embedded sections and tissue distribution.
AB - A polyclonal antibody against 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine
(PhIP)-DNA adducts was raised for their immunohistochemical demonstration in
paraffin-embedded sections. Specificity of this antibody was confirmed by
competitive ELISA. Positive signals were immunohistochemically detected in
acetone-fixed but not in formalin- or ethanol-fixed sections from F344 rats
treated by gavage with a single dose of PhIP at 37.5-300 mg/kg and killed at 1,
2, and 7 days thereafter. Dose-dependent positive staining was observed in almost
all organs of both sexes, including the colon, prostate, and mammary gland but
largely independent of the tumor response. Repair activity, judged by
disappearance of adducts with time, differed according to the organ or cell type.
One exception was hepatocytes, the liver incidentally being a nontarget organ.
The results suggest that the generated antibody is applicable for detection of
cells targeted by PhIP in paraffin-embedded sections and also for the
investigation of the mechanisms of PhIP-carcinogenesis.
PMID- 9766659
TI - Squamous cell hyperplastic foci: precursors of cutaneous papillomas induced in
SENCAR mice by a two-stage carcinogenesis regimen.
AB - We have conducted a series of experiments to characterize the lesions that are
precursors of cutaneous papillomas in SENCAR mice initiated with 7,12
dimethylbenz(a)anthracene (DMBA) and promoted with 12-O-tetradecanoylphorbol-13
acetate (TPA). The first grossly detectable lesions at sites where papillomas
subsequently developed were papules, slightly raised areas of skin ranging in
diameter from 0.25 to approximately 1.5 mm. Papules were first detected in DMBA
initiated mice 21 days after the start of dosing with TPA. Of 78 DMBA/TPA-induced
papules tracked during 15 weeks of TPA treatments, 68% progressed to papillomas,
9% persisted as papules, and 22% completely regressed. Histological evaluation of
serial sections of 69 DMBA/TPA-induced papules revealed that they were focal
hyperplastic lesions that we refer to as squamous cell hyperplastic foci (SCHF).
These hyperproliferative lesions appeared to progress through two distinct
stages. Stage I SCHF were characterized as regular hyperplastic foci involving
the interfollicular epidermis and the outer root sheaths of 1 or more hair
follicles down to the level of the sebaceous glands. Stage II SCHF were foci of
irregular epithelial hyperplasia with increased fibrovascular stroma and involved
from 3 to >10 hair follicles. Prominent dilated capillaries and inflammatory cell
infiltrates were frequently associated with both stage I and II SCHF. Ha-ras gene
codon 61 mutations were detected in 7 of 10 stage I SCHF and 13 of 14 stage II
SCHF microdissected from histological sections and 7 of 7 of whole papules by
mutation-specific PCR analysis. These data provide molecular evidence that SCHF
are foci of initiated cells. Further study of these lesions may contribute to
more fully defining the sequence of molecular and cellular changes necessary for
tumorigenesis in mouse skin. SCHF may also have utility as early indicators of
potential skin tumorigenicity in cancer bioassays.
PMID- 9766660
TI - Human single-chain Fv antibodies to MUC1 core peptide selected from phage display
libraries recognize unique epitopes and predominantly bind adenocarcinoma.
AB - The tumor-associated antigen MUC1 is overexpressed and underglycosylated in human
adenocarcinomas of diverse origins, such as breast, ovary, and colon. We isolated
and describe five human single-chain (sc) Fv antibodies specific for the MUC1
variable number of tandem repeats region isolated by in vitro selection from a
large naive phage antibody library containing over 6 x 10(9) different scFv
antibodies. A synthetic biotinylated 100-mer peptide corresponding to five tandem
repeats of the MUC1 peptide core was used for selection. Two of the antibodies
were highly specific for MUC1 as judged by ELISA and flow cytometry. In
immunohistochemistry, antibody clone 10A stained MUC1 in the cytoplasm and
membrane of adenocarcinoma cells of breast and ovary, whereas in normal
epithelium, only cytoplasmic or no staining was observed. With antibody clone
10B, staining was less pronounced and was not always membrane associated in
adenocarcinoma. Determination of the fine specificity of 10A and 10B using a
novel "indirect epitope fingerprinting" ELISA showed that both antibodies
recognize unique epitopes that have not been described for hybridoma-derived anti
mucin antibodies of mouse origin. The selected human antibodies, like many of the
murine MUC1 antibodies, recognize epitopes on the protein core of MUC1 that are
abundantly present in the underglycosylated form of cell surface mucin on
adenocarcinoma. The best human scFv, clone 10A, appears to distinguish normal
cells from adenocarcinoma cells, which makes it an attractive candidate for use
in antibody-based tumor targeting.
PMID- 9766661
TI - Imaging herpes virus thymidine kinase gene transfer and expression by positron
emission tomography.
AB - We report a series of studies that assess the feasibility and sensitivity of
imaging of herpes virus type one thymidine kinase (HSV1-tk) gene transfer and
expression with [124I]-5-iodo-2'-fluoro-1-beta-D-arabinofuranosyluracil ([124I]
FIAU) and positron emission tomography (PET) and the ability of [124I]-FIAU-PET
imaging to discriminate different levels of HSV1-tk gene expression. Studies were
performed in rats bearing multiple s.c. tumors derived from W256 rat carcinoma
and RG2 rat glioma cells. In the first set, we tested the sensitivity of [124I]
FIAU-PET imaging to detect low levels of HSV1-tk gene expression after retroviral
mediated gene transfer. HSV1-tk gene transduction of one of preestablished wild
type W256 tumor in each animal was accomplished by direct intratumoral injection
of retroviral vector-producer cells (W256-->W256TK* tumors). Tumors produced from
W256 and W256TK+ cells served as the negative and positive control in each
animal. Highly specific images of [124I]-FIAU-derived radioactivity were obtained
in W256TK* tumors (that were transduced in vivo) and in W256TK+ tumors but not in
nontransduced wild-type W256 tumors. The level of "specific" incorporated
radioactivity in transduced portions of both W256TK* and W256TK+ tumors was
relatively constant between 4 and 50 h. In the second set, we tested whether
[124I]-FIAU and PET imaging can measure and discriminate between different levels
of HSV1-tk gene expression. Multiple s.c. tumors were produced from wild-type RG2
cells and stably transduced RG2TK cell lines that express different levels of
HSV1-tk. A highly significant relationship between the level of [124I]-FIAU
accumulation [% injected dose/g and incorporation constant (Ki)] and an
independent measure of HSV1-tk expression (sensitivity of the transduced tumor
cells to ganciclovir, IC50) was demonstrated, and the slope of this relationship
was defined as a sensitivity index. We have demonstrated for the first time that
highly specific noninvasive images of HSV1-tk expression in experimental animal
tumors can be obtained using radiolabeled 2'-fluoro-nucleoside [124I]-FIAU and a
clinical PET system. The ability to image the location (distribution) of gene
expression and the level of expression over time provides new and useful
information for monitoring clinical gene therapy protocols in the future.
PMID- 9766662
TI - Tumor growth inhibition induced in a murine model of human Burkitt's lymphoma by
a proteasome inhibitor.
AB - Cell growth and viability are dependent on the function of the multicatalytic
proteinase complex (proteasome), a multisubunit particle that affects progression
through the mitotic cycle by degradation of cyclins. Exposure of rodent
fibroblasts and human lymphoblasts in culture to benzyloxycarbonyl-leucyl-leucyl
phenylalaninal (Z-LLF-CHO), a cell-permeable peptidyl aldehyde inhibitor of the
chymotrypsin-like activity of the proteasome, resulted in the induction of
apoptosis in a rapid, dose-dependent fashion. Fibroblasts transformed with ras
and myc, lymphoblasts transformed by c-myc alone, and a Burkitt's lymphoma (BL)
cell line that overexpresses c-Myc were up to 40-fold more susceptible to
apoptosis than were either primary rodent fibroblasts or immortalized
nontransformed human lymphoblasts, respectively. To determine whether such
preferential apoptosis could impact upon tumor growth in vivo, toxicological
studies were performed in mice with severe combined immunodeficiency and showed
that mice tolerated single interscapular doses of Z-LLF-CHO without unacceptable
toxicity. Severe combined immunodeficient mice bearing s.c. BL tumors in the
flank were treated interscapularly with Z-LLF-CHO or a comparable dose of the
peptidyl alcohol (Z-LLF-OH), which does not induce proteasome inhibition or
apoptosis. Single doses of Z-LLF-CHO induced statistically significant (P <
0.0001) early tumor regression and a significant (P < 0.0001) delay in tumor
progression. Analysis of tumor specimens revealed increased apoptosis in BL
tumors from mice treated with Z-LLF-CHO. These results, showing a 42% tumor
growth delay, indicate that proteasome inhibitors have the potential of curbing
the growth of a c-myc-related tumor.
PMID- 9766663
TI - Functional nucleoside transporters are required for gemcitabine influx and
manifestation of toxicity in cancer cell lines.
AB - Gemcitabine (2',2'-difluorodeoxycytidine) is a novel pyrimidine nucleoside drug
with clinical efficacy in several common epithelial cancers. We have proposed
that gemcitabine requires nucleoside transporter (NT) proteins to permeate the
plasma membrane and to exhibit pharmacological activity. In humans, there are
seven reported distinct NT activities varying in substrate specificity, sodium
dependence, and sensitivity to inhibition by nitrobenzylthioinosine (NBMPR) and
dipyridamole. To determine which NTs are required for gemcitabine-dependent
growth inhibition, cultures from a panel of 12 cell lines with defined plasma
membrane NT activities were incubated with different concentrations of
gemcitabine. Cell proliferation was assessed by the sulforhodamine B assay and
cell enumeration to identify the concentrations of gemcitabine that inhibited
cell replication by 50% (IC50s). NT activity was a prerequisite for growth
inhibition in vitro because: (a) the nucleoside transport-deficient cells were
highly resistant to gemcitabine; and (b) treatment of cells that exhibited only
equilibrative NT activity with NBMPR or dipyridamole increased resistance to
gemcitabine by 39- to 1800-fold. These data suggested that the type of NT
activities possessed by a cell may be an important determinant of its sensitivity
to gemcitabine and that NT deficiency may confer significant gemcitabine
resistance. We analyzed the uptake kinetics of [3H]gemcitabine by each of five
human NT activities in cell lines that exhibited a single NT activity in
isolation; transient transfection of the cDNAs encoding the human concentrative
NT proteins (hCNT1 and hCNT2) was used to study the cit and cif activities,
respectively. The efficiency of gemcitabine uptake varied markedly among the cell
lines with single NTs: es approximately = cit > ei > cib >>> cif. The
transportability of [3H]gemcitabine was demonstrated by reconstitution of the
human es NT in proteoliposomes, confirming that gemcitabine permeation is a
protein-mediated process.
PMID- 9766664
TI - Reduction of dimesna to mesna by the isolated perfused rat liver.
AB - Mesna is administered with ifosfamide and cyclophosphamide to reduce the
incidence of hemorrhagic cystitis. In the present model of mesna metabolism and
disposition, mesna is rapidly and irreversibly oxidized to dimesna in the plasma,
passes unchanged through the liver, and is then reduced by the kidney and
excreted. Our detection of a high ratio of mesna to dimesna in the plasma of
clinical samples led us to reinvestigate the hepatic metabolism of mesna and
dimesna. We perfused isolated rat livers from female Sprague Dawley rats with
protein-free buffered solution containing dimesna at concentrations observed
during therapy. In single-pass perfusions, each liver was perfused with up to
three dimesna concentrations during consecutive 20-min periods. Recirculating
perfusions were used to study single supratherapeutic concentrations of dimesna
or mesna. Mesna and dimesna concentrations were measured by specific
chromatographic procedures. Dimesna reduction, adjusted by the effluent flow rate
and liver weight (0.4-58.5 nmol/min/g liver), correlated closely by linear
regression (r = 0.98; n = 36) to the perfused dimesna concentration (4.2-249
microM), indicating a clearance of 0.20 ml/min/g liver. The concentration of
dimesna that entered the liver closely matched the summed concentration of mesna
and dimesna emerging in the effluent perfusate (single-pass experiments: slope,
0.98; intercept, -0.30; r = 1.00; n = 31). Only trace amounts of unidentified
thiols were detected in the bile during recirculation of perfusates with 1 mM
mesna or 250 microM dimesna. The effluent mesna concentration correlated
inversely with the flow rate, which was consistent with a low extraction ratio in
the perfusion model. These data suggested that the dimesna reduction rate was
limited by hepatic uptake. Dimesna reduction was decreased by agents that deplete
glutathione. Pretreatment of rats with up to 100 mg/kg ifosfamide did not impair
hepatic dimesna reduction. In control experiments, dimesna was not reduced during
recirculation through the apparatus without a liver. Mesna was oxidized to
dimesna during oxygenation of the perfusate in the reservoir, but mesna injected
directly into the perfusate just before entry into the liver passed unchanged
into the effluent. Extrapolation of the dimesna clearance data from the perfusion
model to humans suggests that hepatic dimesna reduction may counterbalance the
rapid oxidation of mesna in plasma. The proposed equilibrium is consistent with
clinical observations and suggests a new model for mesna metabolism and
disposition.
PMID- 9766665
TI - Phase I trial of temozolomide using an extended continuous oral schedule.
AB - Temozolomide, a methylating imidazotetrazinone, has antitumor activity against
gliomas, malignant melanoma, and mycosis fungoides and is presently administered
as a 5-day oral schedule every 4 weeks. This Phase I study aimed to determine the
maximum tolerated dose of temozolomide administered as a single oral daily dose
for a continuous 6- or 7-week period, evaluate the plasma pharmacokinetics on
this schedule, and compare total plasma exposure over 7 weeks with the
conventional 5-day regimen. Twenty-four patients with varying tumor types (17 of
24 gliomas) received temozolomide. All had clinically evaluable, refractory
disease; normal renal, hepatic, and bone marrow function; and WHO performance
status < or = 2. Temozolomide was administered at 50 mg/m2/day, increasing by 25
mg/m2/day/cohort until at 100 mg/m2/day grade 4 myelotoxicity forced dose
reductions to 85 mg/m2/day, then 75 mg/m2/day. At 75 mg/m2/day the regimen was
extended to 7 weeks, allowing the future potential combination with irradiation
for primary gliomas. Patient responses (standard Union International Contre
Cancer criteria; for gliomas objective response) and toxicity were assessed.
Temozolomide plasma pharmacokinetics were determined on day 1 and at the
beginning of the final week of administration (n = 5). The most frequent
toxicities were myelosuppression and grades 1 and 2 nausea and vomiting. Grade 4
leucopenia and thrombocytopenia occurred in one of four patients receiving 100
mg/m2/day temozolomide and in one of seven patients receiving 85 mg/m2/day. These
hematological toxicities did not exceed grade 2 in 10 patients receiving 75
mg/m2/day temozolomide. One of 4 malignant melanoma patients and 7 of 17 glioma
patients (41%) demonstrated tumor responses. The overall response rate for this
prolonged schedule was 33% (objective response, 7 of 24 patients; partial
response, 1 of 24 patients); also, 6 of 17 glioma patients maintained SD. Peak
plasma temozolomide concentrations were obtained 30-90 min after oral
administration. Elimination in plasma was best described by a monoexponential
equation with an elimination half-life of 96 +/- 16 min. No plasma accumulation
of temozolomide occurred. Toxicity was greatest in higher dose cohorts, with a
resultant maximum tolerated dose of 85 mg/m2/day, whereas lower dose cohorts
tolerated the schedule well. The area under the temozolomide plasma versus time
curve was noncumulative between the first and last week of the schedule.
Temozolomide administration of 75 mg/m2/day over a 7-week period permits a 2.1
fold greater drug exposure/4 weeks in comparison with the 5-day schedule of 200
mg/m2/day repeated every 28 days. The overall response rate was 33% (glioma
patients, 41% and a further 25% SD). Temozolomide (75 mg/m2/day) for 7 weeks is
the recommended starting dose for further assessment of this schedule.
PMID- 9766666
TI - Reversal of CPT-11 resistance of lung cancer cells by adenovirus-mediated gene
transfer of the human carboxylesterase cDNA.
AB - To evaluate the concept that transfer of the human carboxylesterase (CE) gene
will overcome the drug resistance of a solid tumor to CPT-11 (irinotecan), we
used an adenovirus vector (AdCMV.CE) carrying human CE cDNA to infect CPT-11
resistant A549 human adenocarcinoma cells (A549/CPT) in vitro and in vivo and
evaluated cell growth over time. The A549/CPT cells, selected by stepwise and
continuous exposure of parental A549 cells to CPT-11 over 10 months, had a 6-fold
resistance to CPT-11 and 42% CE activity in comparison with parental A549 cells.
AdCMV.CE infection resulted in an increase in functional CE protein in resistant
cells in vitro that was sufficient to convert CPT-11 to its active metabolite, SN
38, and effectively suppressed resistant cell growth in vitro in the presence of
CPT-11. When AdCMV.CE was directly injected into established s.c. resistant A549
based tumors in nude mice receiving CPT-11, there was a 1.8-fold reduction in
tumor size at day 20 compared to that of controls (P < 0.05). These observations
suggest that adenovirus-mediated gene transfer of the human CE gene and
concomitant administration of CPT-11 may have potential as a strategy for local
control of acquired CPT-11 resistance of solid tumors.
PMID- 9766668
TI - Influence of melatonin on invasive and metastatic properties of MCF-7 human
breast cancer cells.
AB - Melatonin, the principal pineal gland hormone, exerts a direct antiproliferative
effect on estrogen-responsive MCF-7 cells in culture. The purpose of the current
study was to investigate the effects of melatonin on the invasion capacity of MCF
7 cells. In vitro, melatonin at physiological doses (1 nM) reduced (P < 0.001)
the invasiveness of tumoral cells measured in Falcon invasion chambers.
Subphysiological (0.1 pM) and pharmacological concentrations (10 microM) of
melatonin failed to inhibit cell invasion. Melatonin was also able to block
17beta-estradiol-induced invasion (P < 0.001). Pretreatment of MCF-7 cells with 1
nM melatonin increased the response of tumoral cells to the anti-invasive effects
of this indolamine. To explore possible mechanisms by which melatonin reduces
invasiveness, we measured the attachment of MCF-7 cells to a basement membrane,
the chemotactic response of the cells, and their type IV collagenolytic activity.
The presence of melatonin (1 nM) in the culture medium significantly reduced the
ability of MCF-7 cells to attach to the basement membrane; this effect was
enhanced by pretreating the cells with the same indolamine (P < 0.001). Melatonin
also counteracts the stimulatory effects of 17beta-estradiol on cell adhesion (P
< 0.001). The chemotactic response of MCF-7 cells also decreased in the presence
of 1 nM melatonin, and this melatonin-induced reduction of cell migration was
more effective on cells that were previously incubated for 5 days with melatonin
than it was on nonpretreated cells (P < 0.001). The simultaneous addition of
17beta-estradiol and melatonin resulted in a significantly lower chemotactic
response than that of 17beta-estradiol-treated cells (P < 0.001). However, type
IV collagenolytic activity was not influenced by melatonin. Our results
demonstrate that melatonin reduces the invasiveness of MCF-7 cells, causing a
decrease in cell attachment and cell motility, probably by interacting with the
estrogen-mediated mechanisms of MCF-7 cell invasiveness. In addition, we also
studied the influence of melatonin on the expression of two cell surface adhesion
molecules (E-cadherin and beta1 integrin) and an intermediate filament protein
(vimentin), the expression of which has been correlated with the relative
invasive capacity of human breast cancer cells. The culture of tumor cells in the
presence of melatonin (1 nM) increased the membrane staining for E-cadherin and
beta1 integrin as well as the number of E-cadherin and beta1 integrin
immunoreactive cells (P < 0.01). Neither control MCF-7 cells nor those treated
with melatonin stained for vimentin. Preliminary in vivo experiments carried out
on ovariectomized athymic nude mice implanted with 17beta-estradiol pellets and
inoculated with 5 x 10(6) MCF-7 cells in the inguinal mammary fat pad suggest
that melatonin could decrease the tumorigenicity of these tumor cells. However,
these results need further confirmation. Taken together, our results suggest that
melatonin shifts MCF-7 human breast cancer cells to a lower invasive status by
increasing the beta1 integrin subunit and E-cadherin expression and promoting the
differentiation of tumor cells. Finally, our study points out the existence of
the anti-invasive actions of melatonin as a part of the oncostatic action of
melatonin.
PMID- 9766667
TI - Inhibition of phosphoinositide 3-kinase related kinases by the radiosensitizing
agent wortmannin.
AB - Members of the phosphatidylinositol-3 kinase related kinase (PIKK) family
function in both cell cycle progression and DNA damage-induced cell cycle
checkpoints. The fungal metabolite, wortmannin, is an effective radiosensitizer
that irreversibly inhibits certain members of the PIKK family. Based on their
roles in DNA damage responses, several PIKKs, DNA-dependent protein kinase (DNA
PK), ataxia telangiectasia mutated (ATM) and the ataxia- and Rad3-related protein
(ATR), are potential targets for the radiosensitizing effect of wortmannin. In
this report, we demonstrate that wortmannin is a relatively potent inhibitor of
DNA-PK (IC50, 16 nM) and ATM (IC50, 150 nM) activities, whereas ATR activity is
significantly less sensitive to this drug (IC50, 1.8 microM). In intact A549 lung
adenocarcinoma cells, wortmannin inhibited both DNA-PK and ATM at concentrations
that correlated closely with those required for radiosensitization. Furthermore,
pretreatment of A549 cells with wortmannin resulted in radioresistant DNA
synthesis, a characteristic abnormality of ATM-deficient cells. These results
identify wortmannin as an inhibitor of ATM activity and suggest that ATM and DNA
PK are relevant targets for the radiosensitizing effect of this drug in cancer
cells.
PMID- 9766669
TI - Retroviral transfer of human cytochrome P450 genes for oxazaphosphorine-based
cancer gene therapy.
AB - Cyclophosphamide (CPA) and ifosfamide (IFA) are widely used anticancer prodrugs
that are bioactivated in the liver by specific cytochrome P450 enzymes (CYPs).
The therapeutic activity of these antitumor agents can be compromised by a low
therapeutic index that is, in part, due to the systemic distribution of activated
drug metabolites. Here, recombinant retroviruses were used to deliver six
different CPA- or IFA-metabolizing human CYP genes to 9L gliosarcoma cells: 2B6,
2C8, 2C9, 2C18 (Met385 and Thr385 alleles), 2C19, and 3A4. Intratumoral
cytochrome P450 expression conferred substantial sensitivity to CPA cytotoxicity,
with the most dramatic effects seen with CYP2B6. Strong CPA chemosensitivity was
also seen following transduction of CYP2C18-Met, despite a very low level of CYP
protein expression (>60-fold lower than that of 2B6). In contrast to CPA, the
cytotoxicity of IFA was greatest toward tumor cells transduced with CYP3A4,
followed by CYPs 2B6 and 2C18-Met. A substantial further increase in
chemosensitivity was achieved upon transduction of 2B6 or 2C18-Met-expressing
tumor cells with P450 reductase, which provided for more efficient intratumoral
prodrug activation and cytotoxicity at lower drug concentrations. With 2B6- plus
P450 reductase-transduced tumor cells, CPA but not IFA conferred a strong cell
contact-independent bystander cytotoxic effect on non-P450-expressing 9L cells.
CPA treatment of tumors that were transduced with 2B6 or 2C18-Met together with
P450 reductase and were grown s.c. in immunodeficient mice resulted in a large
enhancement of the liver P450-dependent antitumor effect seen with control 9L
tumors, with no apparent increase in host toxicity (growth delay of >25-50 days
in P450-expressing tumors versus approximately 5-6 days without P450). CYP2B6
plus P450 reductase and CYP2C18-Met plus P450 reductase thus appear to be
excellent gene combinations for use with CPA in P450/prodrug activation-based
cancer gene therapy.
PMID- 9766670
TI - p53 mutations in skin and internal tumors of xeroderma pigmentosum patients
belonging to the complementation group C.
AB - Fifty-eight skin biopsies and three primary internal tumors from patients
affected by the rare hereditary disease xeroderma pigmentosum (XP) were studied
by an improved PCR-single strand conformation polymorphism analysis to detect the
mutations of the tumor suppressor gene p53. The results from cutaneous XP tumors,
including 27 squamous cell carcinomas and 6 basal cell carcinomas, show a very
high level (86%) of p53 mutations. The analysis of mutations found in XP skin
cancers according to the complementation group of the patients shows that tandem
CC-->TT transitions are a characteristic of XP-C patients with a frequency much
higher in their skin tumors (85%) compared with tumors in XP patients who do not
belong to group C (33%). In all XP-C biopsies, mutations were due to replication
of unrepaired DNA lesions on the nontranscribed strand of the p53 gene,
substantiating the preferential repair in vivo of the transcribed strand of this
gene in human tissues. For the first time, we were able to analyze three primary
internal tumors (a neuroendocrine tumor of the thyroid, a gastric adenocarcinoma,
and a glioma of the brain) of young XP children. All of them contained one
mutation on the p53 gene, which were different from the ones found in the XP skin
tumors and could have resulted from unrepaired lesions caused by oxidative
damage.
PMID- 9766671
TI - Apurinic endonuclease (Ref-1) is induced in mammalian cells by oxidative stress
and involved in clastogenic adaptation.
AB - Apurinic endonuclease (APE; also known as Ref-1 protein) is a key enzyme in base
excision repair, cleaving apurinic sites that arise spontaneously because of the
activity of DNA glycosylases. To address the question of whether APE can be
modulated by genotoxic stress affecting cellular protection, we analyzed the
expression of APE in Chinese hamster ovary (CHO) cells after treatment with
various genotoxic agents. We show that treatment of CHO cells with hydrogen
peroxide (H2O2) or sodium hypochlorite (NaOCl) increases the levels of APE mRNA
and protein. APE induction was observed 3-9 h after treatment and was accompanied
by an increase in APE activity. We also show that the cloned human APE promoter
transfected into CHO cells is stimulated by the oxidants, indicating
transcriptional activation of the APE gene. When cells were pretreated with
NaOCl, inducing APE, and then challenged with H2O2, the clastogenic effect of the
challenge dose was significantly reduced, suggesting clastogenic adaptation due
to APE induction. To further prove the involvement of APE in adaptation against
induced chromosomal breakage, we transfected human APE cDNA driven by an
inducible promoter into CHO cells and observed that transient induction of APE
reduced the clastogenic effect of H2O2. Overall, the data demonstrate that the
APE gene can be activated by oxidative agents, resulting in a transient increase
in APE repair activity, which reduces the clastogenic response of cells to an
oxidative agent. The protection of cells from chromosomal aberrations seen after
prior exposure to oxidants is attributed to an adaptive response to oxidative
stress.
PMID- 9766672
TI - Mutation of the MENIN gene in sporadic pancreatic endocrine tumors.
AB - Pancreatic endocrine tumors occur both sporadically and as part of the multiple
endocrine neoplasia type 1 (MEN1) syndrome. MEN1 is an autosomal dominant disease
characterized by parathyroid hyperplasia, pancreatic endocrine tumors, and
pituitary adenomas. The MEN1 gene called MENIN maps to chromosome 11q13 and is
thought to function as a tumor suppressor gene. We previously demonstrated loss
of heterozygosity (LOH) at 11q13 in approximately 40% of sporadic pancreatic
endocrine tumors and hypothesize that MENIN is involved in the development of
these tumors. Thirty-one sporadic pancreatic endocrine tumors were analyzed for
mutation of MENIN by nonradioactive single-stranded conformation polymorphism.
Twelve mutations were detected in 31 sporadic pancreatic endocrine tumors (34%).
Twelve of these 31 tumors previously demonstrated loss of heterozygosity at
11q13. Of the tumors with LOH, seven contained mutations of the MENIN gene (58%).
The majority of the MENIN mutations occurred within exon 2. Two independent
mutations in MENIN were detected in a gastrinoma that also revealed LOH, leading
to the possibility of another tumor suppressor gene locus at 11q13. Mutations
were present in both benign and malignant pancreatic endocrine tumors, suggesting
that a MENIN gene mutation is a frequent and early event in the tumorigenesis.
The high incidence of truncating mutations in tumors with LOH at 11q13 support
the hypothesis that MENIN is a tumor suppressor gene.
PMID- 9766673
TI - High incidence of loss of heterozygosity in breast tumors from carriers of the
BRCA2 999del5 mutation.
AB - Germ-line mutation in the BRCA2 gene confers an increased risk of breast cancer.
An elevation of additional genetic defects in tumors of patients with germ-line
mutation in the BRCA2 gene compared with sporadic breast tumors has been
reported. To evaluate the nature of the difference, we did detailed mapping of
chromosomes 1p, 3p, 6q, 11, 13q, 16q, 17, and 20q, using microsatellite markers.
We found that the frequency of loss of heterozygosity was similar at some
chromosomal regions in the BRCA2 999del5 and sporadic tumors but significantly
different at others. These others include chromosomal arms 3p, 6q, 11p, 11q, 13q,
and 17p. Loss of heterozygosity mapping suggests that the same chromosome regions
are involved in both tumor groups but at elevated frequencies in BRCA2 999del5
tumors. This higher frequency of genetic aberrations could pinpoint genes that
selectively promote tumor progression in individuals predisposed to breast cancer
due to the BRCA2 999del5 germ-line mutation. Accumulation of somatic genetic
changes during tumor progression may follow a specific and more aggressive
pathway of chromosome damage in these individuals.
PMID- 9766674
TI - Insulin-like growth factor II and PAX3-FKHR cooperate in the oncogenesis of
rhabdomyosarcoma.
AB - The mouse myoblast C2C12 cell line transfected singly with cDNA for Pax-3, PAX3
FKHR, or insulin-like growth factor (IGF) II or cotransfected with IGF-II plus
Pax-3 or with IGF-II plus PAX3-FKHR genes showed an altered morphology, a lack of
differentiation, and higher proliferation rates in vitro. On s.c. injection into
nude mice, tumors grew from transfected cell lines but not from cells transfected
with the empty vector. Tumors derived from IGF-II/PAX3-FKHR- and IGF-II
transfected cells grew most rapidly. Cotransfection of IGF-II plus Pax-3 induced
tumors comprised highly differentiated striated muscle cells; Pax-3, PAX3-FKHR,
or IGF-II transfection produced tumors at varying stages of differentiation.
Tumors derived from IGF-II plus PAX3-FKHR-cotransfected cells were composed of
undifferentiated cells. This was the only tumor type to infiltrate the underlying
muscle. The most angiogenesis and the least apoptosis were observed in the latter
tumors. These results support the hypothesis that PAX3-FKHR interacts with IGF-II
to play a critical role in the oncogenesis of rhabdomyosarcoma.
PMID- 9766675
TI - Aberrant expression of double-stranded RNA-dependent protein kinase in
hepatocytes of chronic hepatitis and differentiated hepatocellular carcinoma.
AB - We immunohistochemically analyzed the expression of double-stranded RNA-dependent
protein kinase (PKR) using a monoclonal antibody, 71/10. Test samples included 64
human liver biopsies and 25 liver sections of rats inoculated with
diethylnitrosamine. The PKR signals in human fatty livers and normal rat livers
were minimum. Scoring signal intensity from 0-4, the average scores of chronic
active (14 cases) and chronic persistent (6 cases) hepatitis associated with
hepatitis virus C (HCV) were 2.8 and 2.0, respectively (P = 0.038). The stained
cells were significantly more abundant in the periportal than centrilobular
regions for both chronic active and persistent hepatitis (P < 0.001 each). The
average score of liver cirrhosis associated with HCV was 1.9. Those scores of
well-, moderately, and poorly differentiated hepatocellular carcinomas associated
with HCV were 3.4, 2.1, and 0.3, respectively (P < 0.001 for each pair). Those
scores of well- and poorly differentiated carcinomas associated with hepatitis
virus B were 2.3 and 0.0, respectively (P < 0.001). The average score of rat
carcinomas induced by diethylnitrosamine was 1.9. Morphologically, nuclei of the
vast majority of PKR-positive cells looked not apoptotic. The ratio of PKR
positive cells to apoptotic cells by terminal transferase-mediated dUTP nick end
labeling method was approximately 20 in hepatitis, and over 100 in well
differentiated carcinoma.
PMID- 9766676
TI - Inhibition of tumor cell growth by RTP/rit42 and its responsiveness to p53 and
DNA damage.
AB - Through a differential screening technique, we have identified a cDNA clone with
differential expression in normal versus tumor cells. This clone, designated
rit42 (reduced in tumor, 42 kDa), was previously isolated as a homocysteine
inducible gene in human endothelial cells (RTP), and the same or a highly related
androgen-responsive gene in mouse has also been identified. Both Northern blot
analysis and in situ hybridization demonstrated a significantly diminished
expression in tumor cells, including those derived from breast and prostate when
compared with normal cells. It was shown that RTP/rit42 mRNA cycles with cell
division, peaking at G1 and G2-M, with lower expression in S phase. The biphasic
expression of RTP/rit42 mRNA was absent in tumor cells. Introduction of rit42
cDNA into human cancer cells reduced cell growth both in vitro and in nude mice.
Moreover, analysis of a tetracycline-regulated p53-inducible system in null-p53
cell lines showed that RTP/rit42 mRNA expression increased concomitantly with p53
expression and followed a similar time course. In addition, DNA-damaging agents
induced RTP/rit42 expression in a p53-dependent manner but independent of a p53
mediated G1 arrest. Immunofluorescence analysis of a FLAG epitope-tagged
RTP/rit42 protein revealed a cytoplasmic localization pattern with redistribution
to the nucleus upon DNA damage. We have localized RTP/rit42 to human chromosome
8q24.3. Taken together, these results are consistent with a growth inhibitory
role for RTP/rit42, and its down-regulation may contribute to the tumor malignant
phenotype.
PMID- 9766677
TI - Multiple changes in gene expression are associated with normal cell-induced
modulation of the neoplastic phenotype.
AB - Specific regulatory pathways in neoplastic cells seem to be responsive to control
signals provided by the normal cell/tissue environment. The present experiments
were designed to define, at the molecular level, the growth-regulatory signals in
neoplastic cells that are associated with the modulation of expression of the
neoplastic phenotype by normal cell populations. When cultured in the presence of
normal cell-conditioned medium, a highly malignant rat tracheal carcinoma-derived
cell population (IC-12) undergoes dramatic changes in morphology, and the
anchorage-independent growth of these cells is inhibited. This phenomenon is
termed normalization. The strategy adopted for elucidating the cellular/molecular
changes associated with the induction of these phenotypic alterations was to
define the differences in mRNA expression patterns between IC-12 populations
exhibiting the neoplastic phenotype (wild-type cells) and those exhibiting the
normalized phenotype. For this purpose, the differential display technique and
subsequent Northern blot analyses were used. Once specific, differentially
expressed genes were identified, the temporal sequence of altered gene expression
was determined by monitoring the levels of mRNA expression after the addition of
normal cell-conditioned medium. Some of the identified known genes are grouped
into three general categories: (a) group I genes are those involved in cellular
adhesion processes; (b) group II genes are those involved in signal transduction
pathways; and (c) group III genes are those involved in transcriptional and
translational processes. Genes that are differentially expressed during the
normalization process seemed to exhibit characteristic temporal expression
patterns after the addition of normal cell-conditioned medium. Identification of
these differentially expressed genes and their associated cellular functions
provide insight into some of those regulatory pathways in neoplastic cells that
are amenable to regulation by normal cells. An analysis of the temporal sequence
of altered gene expression provides further information that allows the
identification of those genes that are likely to be critical upstream effectors
regulating transcriptional regulatory events that result in the moderation of
neoplastic behavior.
PMID- 9766678
TI - Molecular ordering of apoptosis induced by anticancer drugs in neuroblastoma
cells.
AB - Apoptosis mediated by anticancer drugs may involve activation of death-inducing
ligand/receptor systems such as CD95 (APO-1/Fas), cleavage of caspases, and
perturbance of mitochondrial functions. We investigated the sequence of these
events in SHEP neuroblastoma cells transfected with Bcl-2 or Bcl-X(L) using two
different drugs, namely, doxorubicin (Doxo), which activates the CD95/CD95 ligand
(CD95-L) system, and betulinic acid (Bet A), which does not enhance the
expression of CD95 or CD95-L and which, as shown here, directly targets
mitochondria. Apoptosis induced by both drugs was inhibited by Bcl-2 or Bcl-X(L)
overexpression or by bongkrekic acid, an agent that stabilizes mitochondrial
membrane barrier function, suggesting a critical role for mitochondria. After
Doxo treatment, enhanced CD95/CD95-L expression and caspase-8 activation were not
blocked by Bcl-2 or Bcl-X(L) and were found in cells with a mitochondrial
transmembrane potential (delta psi(m)) that was still normal (delta psi(m)high
cells). In marked contrast, after Bet A treatment, caspase-8 activation occurred
in a Bcl-2- or Bcl-X(L)-inhibitable fashion and was confined to cells that had
lost their delta psi(m) (delta psi(m)low cells). Mitochondria from cells treated
with either Doxo or Bet A induced cleavage of both caspase-8 and caspase-3 in
cytosolic extracts. Thus, caspase-8 activation may occur upstream or downstream
of mitochondria, depending on the apoptosis-initiating stimulus. In contrast to
caspase-8, cleavage of caspase-3 or poly(ADP-ribose)polymerase was always
restricted to delta psi(m)low cells, downstream of the Bcl-2- or Bcl-X(L)
controlled checkpoint of apoptosis. Cytochrome c, released from mitochondria
undergoing permeability transition, activated caspase-3 but not caspase-8 in a
cell-free system. However, both caspases were activated by apoptosis-inducing
factor, indicating that the mechanism of caspase-8 activation differed from that
of caspase-3 activation. Taken together, our findings demonstrate that
perturbance of mitochondrial function constitutes a central coordinating event in
drug-induced cell death.
PMID- 9766679
TI - Enhanced expression of urokinase receptor induced through the tissue factor
factor VIIa pathway in human pancreatic cancer.
AB - Overexpression of tissue factor (TF) is characteristically observed in advanced
pancreatic cancer and has been associated with invasion and metastasis.
Functional responses of TF activation are here investigated using as a model
system the human pancreatic cancer cell lines SW979 (which overexpresses TF) and
MIAPaCa2 (which does not express detectable levels). After stimulation of these
cell lines with factor VIIa (FVIIa), the only known TF ligand, expression of
urokinase receptor (uPAR) gene was up-regulated in SW979 cells in a dose
dependent manner but not in MIAPaCa2 cells. Interestingly, urokinase (uPA) and
its specific inhibitor PAI-1 were not up-regulated. Exposure to functionally
inactivated FVIIa did not show any effect on uPAR expression on SW979 cells
despite binding to TF with higher efficiency. The neutralizing anti-TF antibody
5G9 blocked the FVIIa-induced up-regulation of uPAR completely, whereas hirudin
failed to block this up-regulation. Treatment of SW979 cells with Factor Xa did
not up-regulate the expression of uPAR gene, whereas treatment with FVII induced
the same level of enhanced uPAR gene expression as that with FVIIa. In the
matrigel invasion assay, enhanced invasion of SW979 cell line induced by FVIIa
was completely inhibited by anti-TF antibody and alpha2-antiplasmin. Moreover,
the endogenous levels of uPAR gene expression were significantly correlated with
the level of TF gene expression in 19 human cancer cell lines (P < 0.05). These
data suggest that up-regulation of uPAR expression by tumor cells leading to
tumor invasion is induced through the TF-FVIIa pathway rather than TF-initiated
thrombin generation. This is the first report that TF may be one of the key
receptors that can up-regulate expression of the plasminogen activator receptor
in human cancer cells to enhance tumor invasion and metastasis.
PMID- 9766680
TI - Selective localization of matrix metalloproteinase 9, beta1 integrins, and human
lymphocyte antigen class I molecules on membrane vesicles shed by 8701-BC breast
carcinoma cells.
AB - The shedding of membrane vesicles from the cell surface is a vital process
considered to be involved in cell-cell and cell-matrix interactions and in tumor
progression. By immunoelectron microscopic analysis of surface replicas of 8701
BC human breast carcinoma cells, we observed that membrane vesicles shed from
plasma membranes contained densely clustered gelatinase B [matrix
metalloproteinase 9 (MMP-9)], beta1 integrins, and human lymphocyte antigen class
I molecules. By contrast, alpha-folate receptor was uniformly distributed on the
smooth cell membrane and shedding areas. Both cell surface clustering of selected
molecules and membrane vesicle release were evident only when cells were cultured
in the presence of serum. Vesicle shedding occurred preferentially at the edge or
along narrow protrusions of the cell. Specific accumulation of proMMP-9 and
active forms of MMP-9 in shed vesicles was also demonstrated by gelatin
zymography. In addition, Western blotting analysis showed the presence of a large
amount of proMMP-9/tissue inhibitor of metalloproteinase 1 complex. The release
of selected areas of plasma membranes enriched with MMP-9 and beta1 integrins
indicates that membrane vesicle shedding from tumor cells plays an important role
in the directional proteolysis of the extracellular matrix during cellular
migration. The presence of human lymphocyte antigen class I antigens suggests a
mechanism for tumor cells to escape from immune surveillance.
PMID- 9766681
TI - Novel human malignancy-associated gene (MAG) expressed in various tumors and in
some tumor preexisting conditions.
AB - We have identified a novel human malignancy-associated gene (MAG) expressed in
various malignant tumors including glioblastomas and hepatocellular carcinomas
(HCCs) and in tumor preexisting conditions such as hepatitis C virus- and
hepatitis B virus-induced liver cirrhosis. The expression of MAG was
characterized using reverse transcription-PCR (RT-PCR), rapid amplification of
cDNA ends PCR, RNA dot blotting, RNase protection assay, and Northern blot
analysis. Rapid amplification of cDNA ends PCR yielded a 536-bp MAG fragment in
HCC, macroregenerative liver nodules with dysplasia, and liver cirrhosis but not
in normal liver or placenta. By RT-PCR, MAG expression was not found in 12
different normal tissues but found in 46 of 51 (90%) premalignant and malignant
tissues of various sites. Embryonic liver and brain were positive for MAG
expression together with tumors from the same organs, but the corresponding
normal adult tissues were negative. By RNase protection assay, MAG mRNA was
expressed in the HepG2 liver tumor cell line and in an ovarian carcinoma but not
in normal liver. The estimated transcript size from Northern blot analysis was
8.8 kb. This novel gene may play a role in the progression of premalignant
conditions and in the development of HCC and other cancers.
PMID- 9766682
TI - Correspondence re: J. Benitez et al., A region of allelic imbalance in 1q31-32 in
primary breast cancer coincides with a recombination hot spot. Cancer Res., 57:
4217-4220, 1997.
PMID- 9766684
TI - Electroencephalographic findings in functional psychoses: state or trait
indicators?
AB - The clinical significance of electroencephalographic (EEG) changes in patients
with functional psychoses is not yet clearly defined, particularly whether these
changes are state indicators or trait indicators. In the present review, the EEG
abnormalities in schizophrenia are discussed. In early EEG studies of
schizophrenics, the various specific EEG patterns were suggested to be trait
indicators, but those findings were not confirmed. The EEG patterns of some
patients with catatonic schizophrenia, especially periodic catatonia, were
thought to be episode or state indicators, and some of the patients diagnosed as
having atypical psychoses in Japan were suggested to show state indicator EEG
findings. As the computerized and spectral analyses of EEG have advanced, the
contradictory findings of EEG in schizophrenia have been reported, interpreted as
'hyperstable' or 'hypernormal' EEG findings and 'hypofrontal' EEG findings (slow
waves in the frontal region). However, no conclusion can be made as to whether
these EEG findings are state or trait indicators. On the borderland of functional
psychoses, the behavioral changes in temporal lobe epilepsy were described as a
trait indicator, and the psychotic states in non-convulsive generalized status
epilepticus and acute confusional states were suggested to be state indicators.
Further studies of EEG abnormalities in schizophrenia are necessary from multi
dimensional perspectives, including in comparison with the symptomatic psychoses.
PMID- 9766683
TI - Recent advances in dementia research in Japan: non-Alzheimer-type degenerative
dementias.
AB - In this article, we review recent reports by Japanese researchers on non
Alzheimer-type degenerative dementias. These dementias can be classified into the
following subtypes: dementias with Lewy bodies, including diffuse Lewy body
disease, dementias with neurofibrillary tangles, dementias with glial tangles,
including progressive supranuclear palsy and corticobasal degeneration,
argyrophilic grain dementia, frontotemporal dementias including Pick's disease;
dementias with degeneration of subcortical nuclei, including Huntington's disease
and, last, unclassified dementias. Recently, these various forms of dementia have
received much attention in Japan, as elsewhere.
PMID- 9766685
TI - Behavioral characteristics of 187 young adults with autism.
AB - A survey was conducted on the present behavioral characteristics of 187 cases of
adult autism in patients over 18 years of age employing Achenbach's Child
Behavior Checklist (CBCL). When their behavioral characteristics were evaluated
in relation to Present Language Developmental Level (PLDL) and Present Adaptive
Level (PAL), it was seen that greater variation in behavior characteristics was
seen among those exhibiting increasingly lower PLDL and PAL scores. Behavior
characteristics reminiscent of depression were noted even among those exhibiting
high PLDL. Behavior pointing to obsession was found in common among almost all
cases of autism irrespective of PLDL or PAL. Psychotic symptoms such as
hallucinations and delusions were absent in most cases. The results of the
present study were indicative not only of the significance of obsessive behavior
in autism, but also its significance in terms of delving further into the
psychopathology of the disorder.
PMID- 9766687
TI - The prevalence and pattern of insomnia in Japanese industrial workers:
relationship between psychosocial stress and type of insomnia.
AB - We examined the prevalence of insomnia among Japanese male industrial workers and
analyzed the effect of psychosocial stress on the prevalence of three types of
insomnia: 'difficulty in falling asleep', 'frequent sleep interruption' and
'early morning arousal'. The study population consisted of male day workers (n =
319) in a manufacturing heavy industry company located in Nagasaki City, Japan.
The subjects answered a questionnaire consisting of six sleep-related items and
24 questions related to occupational and private life conditions. A total of 271
men (average age 40.9 years) completed the questionnaire; a response rate of 85%.
Insomnia within the month preceding the survey was present in 27.7% of the
workers (75/271). Multiple logistic regression analysis demonstrated that
different psychosocial stressors were associated with different types of
insomnia. Visual display terminal (VDT) work overload was significantly
associated with all types of insomnia, while 'over-involvement in the job' was
associated with difficulty in falling asleep and early morning arousal. Our
results demonstrated that the prevalence of insomnia in Japanese workers is
similar to that reported among European and American general adult population.
Our results also indicate that the use of VDT in the workfield is associated with
insomnia.
PMID- 9766686
TI - One-year prognosis of depressive illness in the elderly population in Japan.
AB - A 1-year prospective study of 43 elderly depressed residents (13 men and 30
women) in Nagai City in Japan is described. An initial survey was carried out in
1993 to find depressed residents. The subjects of the survey were 2056 residents
of 65 years of age and older. The Japanese version of the Geriatric Depression
Scale (GDS) was employed as a screening tool in the first phase of the survey. In
the second phase, screened subjects and control subjects were interviewed by
psychiatrists using the Structured Interview for DSM-III-R (SCID). The diagnosis
of depression was made by the psychiatrists on the basis of the results of the
SCID. Forty-three persons were judged to be depressed. At follow-up, 10 were
still depressed and 15 were well. Four were demented. Fourteen dropped out due to
death, hospitalization, absence from home or refusal. The results showed that
approximately half of the elderly depressed persons seemed to recover by the time
of the 1-year follow-up. One-year prognosis of dysthymia was the worst. Some
types of depression seemed to be a precursor for dementia. The concern is with
how the findings may be used as an aid in understanding and planning community
mental health services strategies. The results indicate that it is very important
to pay close attention to patients with depressive illness who do not meet the
criteria for major depression.
PMID- 9766688
TI - Personality differences in the Munich Personality Test between patients with
major depression and panic disorder.
AB - This study attempted to determine whether patients with major depression and
panic disorder could be differentiated by personality features, measured by the
Munich Personality Test (MPT). One of the six MPT personality dimensions,
'rigidity', was developed in relation to the 'melancholic type of personality',
which may be a specific personality feature of depressive subjects. We therefore
hypothesized that the MPT might be sensitive to possible personality differences
between patients with major depression and panic disorder. Sixty-six patients
with major depression and 27 patients with panic disorder, taken from consecutive
intakes at an outpatient unit, were compared in terms of six personality
dimensions of the MPT. The results demonstrated that rigidity could significantly
differentiate the two patient groups, even after the possible confounding effects
on the personality assessments were statistically partialled out. The MPT was
suggested to be powerful for describing distinctive personality features of
depressive subjects from anxiety subjects.
PMID- 9766689
TI - Tourette syndrome in Japan: a nationwide questionnaire survey of psychiatrists
and pediatricians.
AB - In order to shed light on the clinical picture of patients with Tourette syndrome
(TS) treated at medical institutions in Japan, a nationwide survey covering both
pediatric patients and psychiatric patients was conducted. We mailed 316
questionnaires on experience in treating TS cases and the patients' present
conditions etc. to specialists such as psychiatrists and pediatricians. A total
of 164 responded. The survey found 154 TS patients being treated at the time of
survey, 45 (29.2%) had obsessive-compulsive symptoms (OCS), and 10 (6.5%) had
family histories of TS. It was suggested that TS is often associated with OCS and
that familial cases of TS are slightly less common in Japan than they are in the
USA. Of the 116 respondents who described their experiences, 85 (73.2%) said that
they had treated one or more patients displaying the symptoms of frequent
coprolalia, and 42 (36.2%) said that they had treated one or more patients
suffering from developmental disorders. Based on these findings, we speculated
that the rate of coprolalia in Japan is a little higher than the previously
reported 4% and that TS is often associated with developmental disorders.
PMID- 9766690
TI - Mental health of visually and hearing impaired students from the viewpoint of the
University Personality Inventory.
AB - Tsukuba College of Technology is the first national university established as an
institute of higher education for the visually and hearing impaired. We have been
systematically conducting a University Personality Inventory (UPI) survey on our
students since 1989 to understand their mental health. In this study, we compared
the UPI scores of the new students of Tsukuba College of Technology in 1993 and
1994 with unimpaired students from the University of Tsukuba (control group), but
found no significant difference in the UPI scores of the visually impaired and
the control group. However, we noticed a significant difference in the average
UPI scores between the hearing impaired and the control group. The visually
impaired group were divided into four subgroups, UPI scores descended in order
from degree 1 (total blindness), to degrees 2 and 3 (amblyopia), to degree 4
(visual acuity > or = 0.3). The UPI scores of the degree 4 subgroup were
significantly lower than those of the control group. An investigation of the
items for which the check rate was at least 50% showed that the visually impaired
students had a variety of psychological problems, most of which seemed to concern
depression or anxiety as did the normal control group. The number of affirmative
responses increased with low visual acuity. The only one belonging to the 'lie'
scale item was observed in the group of hearing impaired students. Thus,
comparing these three groups from the viewpoint of mental health, we noticed the
hearing impaired group was slightly different from the other two groups, but the
visually impaired group was similar to the normal control group.
PMID- 9766691
TI - Study of the measurement of defense style using Bond's Defense Style
Questionnaire.
AB - Two hundred and seventy healthy university students were surveyed in December
1995 using Bond's Defense Style Questionnaire (DSQ) to measure the subjects'
defense mechanisms. At the same time, a survey using Byrne's R-S Scale
(Repression-Sensitization Scale) of the MMPI (Minnesota multiphasic personality
inventory) and five psychiatric symptom indexes (anxiety, sense of inadequacy,
sensitivity, depression and impulsive anger) selected from the CMI (Cornell
Medical Index-Health Questionnaire) was conducted. Three factors were extracted
from the DSQ through factor analysis: immature defenses, neurotic defenses, and
mature defenses. The results of analysis of variance revealed the following: (i)
for anxiety and anxiety related symptoms, both immature defenses and neurotic
defenses indicated principal effect; (ii) for impulsive anger and depression,
immature defenses presented principal effect; and (iii) for sensitivity and
impulsive anger, interaction between a mature defense style and neurotic defense
style was noted. The relationship between defense styles and psychiatric symptoms
in healthy people is studied in this paper.
PMID- 9766692
TI - 'Chiyamai', a panic-like disorder in woman divers from Hegura Island.
AB - In Hegura Island, Japan, we have recently found female divers who suffer from a
disorder called 'Chiyamai'. From interviews, questionnaires and temporarily
proposed diagnostic criteria for Chiyamai, nine cases from 44 female divers
interviewed, were diagnosed as having Chiyamai. Clinically, Chiyamai is
characterized by a panic-like attack. Ten symptoms were observed during a panic
like attack, compared with 13 symptoms in a panic attack described in the DSM-IV.
The average age at onset was 30 years and the average duration of illness was
approximately 26 years. Several cases were so severe that the patients were
unable to continue diving. Additionally, we report a typical case of Chiyamai,
and discussed the similarities and differences between Chiyamai and anxiety
disorders in the DSM-IV. We suggest that Chiyamai is a panic-like disorder
specific to female divers from Hegura Island and that it is a result of heavy
diving.
PMID- 9766693
TI - The increasing use of anticonvulsants in prophylactic treatment of bipolar
disorder.
AB - The medical records of patents with bipolar disorders who received prophylactic
drug treatments during three time periods from January 1983 to December 1984,
January 1988 to December 1989, and from January 1993 to December 1994, were
reviewed retrospectively. The percentage of lithium monotherapy sharply decreased
from 96% (51/53) in the first study period to 51.9% (83/160) in the third study
period. Carbamazepine monotherapy and combination of lithium and carbamazepine
increased from 3.8% in the first study period to 45.6% in the third study period.
These results suggest that anticonvulsants may become one of the major drug
treatment strategies for bipolar disorder in the future.
PMID- 9766694
TI - The treatment of neuroleptic malignant syndrome using dantrolene sodium.
AB - The use of dantrolene sodium (DS) in the treatment of neuroleptic malignant
syndrome (NMS) was studied from the data of 21 cases of NMS, which satisfied the
diagnostic criteria of Pope et al. The mean dosage of DS was 0.97+/-0.52 mg/kg
per day and the mean duration of treatment was 8.3+/-5.3 days. It was confirmed
that the mean duration of treatment with DS tended to be longer in the cases
involving disturbance of consciousness. However, there were no significant
differences in the duration of treatment or the mean daily dosage, in the cases
without disturbance of consciousness regardless of any other complications and
symptoms. Also, there were no significant differences in the mean duration of
treatment using DS and the mean dosage of DS between five cases that were
considered to be 'typical' and 16 cases that were considered to be 'incomplete'.
In addition, the prognoses of these cases were good such that not even one death
occurred. In 13 cases, the treatment of psychiatric symptoms with thioridazine
was started without recurrence of NMS.
PMID- 9766695
TI - Effects of trazodone hydrochloride and imipramine on polysomnography in healthy
subjects.
AB - Polysomnography was performed on eight healthy men with trazodone hydrochloride,
imipramine and placebo. Trazodone hydrochloride increased slow wave sleep
significantly. Imipramine prolonged rapid eye movement (REM) latency and
decreased the percentage of REM sleep significantly. Trazodone decreased stages 1
and 2 sleep, while imipramine increased it. These findings suggest that the
antidepressive effect of trazodone might be different from that of imipramine
with the suppression of REM sleep.
PMID- 9766696
TI - Neuroleptic-induced Meige's syndrome following akathisia: pharmacologic
characteristics.
AB - A 52-year-old schizophrenic patient acutely showed blepharospasm and
oromandibular dystonia following neuroleptic-induced akathisia. She had suffered
from schizophrenia and been treated with neuroleptics for 15 years and had
manifested tardive dyskinesia 5 years ago. Following a change in her neuroleptic
medication, severe akathisia developed. Two days after the appearance of
akathisia, blepharospasm and oromandibular dystonia appeared. After the
disappearance of akathisia, the disorder continued. The frequency of
blepharospasm ranged from 30 to 40 (times/min). The oral administration of
trihexyphenidyl (6 mg/day), perphenazine (12 mg/day), and fluphenazine (12
mg/day) significantly decreased the frequency of blepharospasm, whereas
carbamazepine (600 mg/day) and sulpiride (1200 mg/day) did not. These results
suggest that overactivity of both cholinergic and dopaminergic functions in the
striatum may be involved in this patient. Our patient, who showed acute onset of
Meige's syndrome following neuroleptic-induced akathisia, is of interest to those
studying the pathogenesis of Meige's syndrome.
PMID- 9766697
TI - Severe chronic active Epstein-Barr virus infection accompanied by virus
associated hemophagocytic syndrome, cerebellar ataxia and encephalitis.
AB - We present a rare case of chronic active Epstein-Barr virus (EBV) infection
showing various clinical outcomes. A 26-year-old man was admitted to our hospital
due to persistent fever and dyspnea. Serologic response of the patient to EBV
indicated chronic active infection. He showed pleuritis, parotitis, chronic
hepatic dysfunction, disseminated intravascular coagulation, virus associated
hemophaghocytic syndrome, acute rhabdomyolysis, acute renal failure, acute
cerebellar ataxia, encephalitis and multiple brain abscesses. None of acyclovir,
gancyclovir, prednisolone or interleukin-2 was effectual to abolish those
abnormalities. This is the first report of transient cerebellar ataxia which
aggravated to panencephalitis associated with chronic EBV infection.
PMID- 9766698
TI - Further characterization of the 5'-flanking promoter region of the human beta1
adrenergic receptor gene.
AB - Further characterization of the 5'-flanking promoter region of the human beta1
adrenergic receptor (AR) gene was attempted. The transcription initiation sites,
determined by the primer extension and the rapid amplification of the 5'-cDNA
end, are multiple in a spanning about 30 nucleotides (-289 to -261 relative to
the translation start site). There exist inverted CCAAT boxes, multiple binding
sites for transcription factor Sp1 and AP-2 nearby transcription initiation
sites, however, this region lacks a typical TATA box. In order to localize the
regulatory region for the basal transcription of the human beta1-AR gene, a
variety of 5'-flanking sequence/chloramphenicol acetyltransferase reporter gene
fusion constructs was prepared and transiently expressed in HeLa cells.
Functional analyses reveal negatively (-3813 to -2925 and -1772 to -796) as well
as positively (-2925 to -1772) regulatory regions, in addition to the region (
796 to -87) being necessary for the basic expression of the human beta1-AR gene.
PMID- 9766699
TI - Anticonvulsant effects of dipotassium clorazepate on hippocampal kindled seizures
in rats.
AB - We examined the anticonvulsant properties of dipotassium clorazepate (DC) against
hippocampal kindled seizures in rats. Adult male Wistar rats were subjected to
kindling 1 week after the implantation of electrodes. After five stage 5 seizures
were induced, the generalized convulsion triggering threshold (GST) was
determined. Dipotassium clorazepate was administered intraperitoneally in rats
that showed two stable stage 5 seizures induced at the GST current intensity.
Dipotassium clorazepate at doses of 1 mg/kg or more produced an anticonvulsant
effect, but did not readily suppress limbic seizures. Dipotassium clorazepate did
not completely suppress after-discharges (AD) even at the highest dose, which was
5 mg/kg. Moreover, raised stimulus intensity failed to affect its efficacy as an
anticonvulsant. The results of the present study suggest that DC has a modest
anticonvulsant potency. It is reasonable to assume that its anticonvulsant
efficacy is primarily due to attenuation of AD propagation rather than the
raising of the seizure triggering threshold at the kindling focus.
PMID- 9766700
TI - Depression among caregivers of the elderly in need of care and their service
utilization: a pilot study.
AB - Twenty-four community residing elderly people in need of care, who were
registered with the municipal welfare center in Miyagi Prefecture, Japan, and
their principal caregivers participated in the study. The principal caregivers
completed a self-administered questionnaire involving their demographic status,
provided data on their utilization of formal services and completed the Center
for Epidemiologic Studies Depression Scale (CES-D). The health visitors examined
the activities of daily living (ADL) and mental status of these 24 elderly
individuals. More than half the caregivers appeared to be depressed. The non
depressed caregivers used significantly more services than the depressed
caregivers even after the caregivers' age was statistically controlled.
PMID- 9766701
TI - The search for novel antiarrhythmic strategies. Sicilian Gambit.
AB - The past fifty years of antiarrhythmic drug development have seen limited success
in prolonging life and reducing morbidity. It is likely that arrhythmias are in
most instances final common pathways through which changes in the cardiac
substrate and in trigger mechanisms are expressed. We propose that the
development and administration of therapies for the arrhythmias themselves, while
offering a panacea for a disease entity that has evolved and is being overtly
manifested, is also an admission of failure to identify and prevent evolution of
the substrate and triggers such that arrhythmias can occur. We suggest that while
strategies for treatment and prevention of recurrence of arrhythmias still
warrant exploration, greater hope for the future lies in identifying means for
earlier diagnosis of the arrhythmogenic substrate and triggers, and in developing
therapies that are "upstream" to the arrhythmia and prevent their initial
expression. Means to achieve this end are suggested, using specific arrhythmias
as examples. Similarly, to increase the likelihood that clinical studies of new
therapies can be successfully concluded and interpreted, we suggest new
approaches to patient selection, risk stratification, trial endpoints, outcome
events and trial methodologies.
PMID- 9766702
TI - Skeletal muscle deoxygenation during exercise assessed by near-infrared
spectroscopy and its relation to expired gas analysis parameters.
AB - The present study was performed to determine the relation between oxygenated
hemoglobin (oxy-Hb) changes in working muscles and ventilatory parameters. Six
active normal subjects, 21 sedentary normal subjects and 16 patients with heart
failure performed an incremental exercise with expired gas analysis.
Deoxygenation of the vastus lateralis muscle was monitored for oxy-Hb changes
using near-infrared spectroscopy. Near the anaerobic threshold (AT), oxy-Hb
started to decrease, forming the first inflection point (P1). Near the
respiratory compensation point (RCP), the second inflection point (P2) was
observed. Oxygen uptake at the AT, RCP, P1 and P2 decreased in magnitude first in
the active normal subjects, then in sedentary normal subjects and finally in the
heart failure patients. High correlation was demonstrated between AT and P1
(r=0.8, p<0.0005) and between RCP and P2 (r=0.9, p<0.0005). In 12 sedentary
normal subjects who underwent repeat exercise, reproducibility was confirmed for
both P1 and P2. Constant work rate exercises were performed in 5 sedentary normal
subjects, and in all of them the oxy-Hb remained unchanged below the AT work
rate, whereas oxy-Hb decreased above the AT work rate. Exercise capacity, with
respect to both working muscle deoxygenation and ventilation, could be evaluated
in detail by the concomitant use of near-infrared spectroscopy and expired gas
analysis.
PMID- 9766703
TI - Influence of aerobic exercise training on brain natriuretic peptide secretion in
patients in the chronic phase of myocardial infarction.
AB - Brain natriuretic peptide (BNP) secretion increases after myocardial infarction
(MI); its plasma level may reflect the degree of left ventricular dysfunction.
This study examines how aerobic exercise therapy for MI influences BNP secretion.
Subjects included 70 patients (mean age, 62.0+/-11.3 years) who were divided into
four groups: (1) 20 patients with an anterior MI and exercise training; (2) 20
patients with an anterior MI and no exercise training; (3) 15 patients with an
inferior MI and exercise training; and (4) 15 patients with an inferior MI and no
exercise training. The training groups performed aerobic exercise 3 times a week
for 2 months. Exercise intensity was defined as a heart rate of anaerobic
threshold (AT), derived from the treadmill cardiopulmonary exercise testing at 1
month after the onset of MI. The subjects underwent cardiopulmonary exercise
testing again at 3 months after the onset of MI. To measure BNP, blood samples
were obtained in the resting state and immediately after the peak exercise. AT
and peak oxygen uptake increased in the training group with anterior MI and in
both the training and nontraining groups with inferior MI. Significant serial
change in plasma BNP level was not observed in the inferior MI groups. Plasma BNP
level decreased longitudinally only in the nontraining anterior MI group. It was
concluded that exercise training in patients with an anterior MI could delay the
recovery of left ventricular function, but will increase exercise tolerance.
PMID- 9766704
TI - Impact of percutaneous transluminal coronary angioplasty on coronary bypass
surgery--changes in the patient profile during the past decade.
AB - As percutaneous transluminal coronary angioplasty has become an increasingly
common procedure replacing coronary artery bypass grafting (CABG), the clinical
profile of the patients referred for CABG has changed markedly. A retrospective
study of the changes in the clinical profile and surgical outcome of patients who
underwent CABG during the past 10 years was conducted. Between March 1982 and
February 1996, 1010 patients underwent isolated CABG at Nara Medical University.
The first 100 consecutive patients who underwent CABG in 1984-85 (group 1) were
compared with the first 100 consecutive patients who underwent CABG in 1994-95
(group 2). Preoperative risk increased significantly during the decade with
respect to patient age (p<0.001), the presence of diabetes mellitus (p=0.048),
the number of diseased vessels (p<0.001), left main trunk disease (p=0.008), the
presence of aortic or peripheral vascular disease (p=0.032),and the need for
emergency surgery (p=0.013). Operative procedures have become more complicated
with respect to the number of total and arterial grafts, duration of the aortic
cross-clamp and cardiopulmonary bypass. Hospital mortality for elective CABG has
not changed (2%) and the overall mortality has not increased significantly (from
2% to 3%) during the decade. In conclusion, although the preoperative risks have
increased and more complicated procedures are required, CABG continues to be
performed safely with low mortality rates.
PMID- 9766705
TI - Head-up tilt test combined with isoproterenol infusion provokes coronary
vasospastic angina.
AB - The association of the autonomic nervous system with coronary vasospasm has been
controversial. The aim of the present study was to examine the involvement of the
autonomic nervous system in coronary vasospasm by applying the head-up tilt (HUT)
test to patients with coronary vasospastic angina. Fifteen consecutive patients
with coronary vasospastic angina and without significant organic coronary
stenoses underwent the HUT test. Prior to the test, coronary spasm was documented
angiographically by using an intracoronary injection of acetylcholine or
ergonovine. The HUT test was performed in the early morning and repeated in the
afternoon if the test was positive in provoking angina pectoris and syncope or
presyncope. If the test was negative, it was repeated under intravenous infusion
of isoproterenol at a rate of 1-2 microg/min. The HUT test under isoproterenol
infusion in the morning provoked vasospastic angina with syncope or presyncope in
9 of the 15 patients. In the test-positive group, heart rate was significantly
reduced (104+/-17 beats/min to 84+/-25 beats/min, p<0.05), which preceded a
reduction in systolic blood pressure (158+/-25 mmHg to 125+/-17 mmHg, p<0.001),
angina attack and syncope. The HUT test without isoproterenol infusion in the
morning and the HUT test in the afternoon with or without isoproterenol infusion
failed to provoke angina. The heart rate reduction preceding reduced systemic
blood pressure and anginal attack suggested that parasympathetic nerve excitation
plays an important role in coronary vasospasm. The results also implied that the
HUT test combined with isoproterenol infusion is useful for the provocation of
coronary spasm.
PMID- 9766706
TI - Changes of ischemic heart disease in Utsunomiya, Japan, over 10 years: a survey
of primary care physicians.
AB - A total of 502 patients presenting in Utsunomiya city and its suburbs during a 10
year period were studied to determine the clinical features of ischemic heart
disease and to identify coronary risk factors. The male/female ratio was 1.21,
but the ratio decreased with increasing age. The duration of chest pain showed a
continuous spectrum between angina and infarction, with a short duration of chest
pain not being useful for excluding the diagnosis of myocardial infarction.
Hypertension was more common than hypercholesterolemia in this study, although
the prevalence of the latter increased slightly with time, along with the shift
towards a modernized occupational pattern. Smoking was a more important risk
factor for ischemic heart disease in younger individuals than in the elderly, and
diabetes mellitus was highly associated with the development of myocardial
infarction. The incidence of radiologically diagnosed cardiac hypertrophy and
aortic calcification decreased over time. These changes may have resulted in part
from improved blood pressure control and the development of new anti-hypertensive
and cholesterol-lowering agents.
PMID- 9766708
TI - Percutaneous revascularization of lesions with saphenous vein graft failure:
influence of chronic total occlusion on early outcome.
AB - The purpose of this study was to evaluate a therapeutic strategy of percutaneous
transluminal coronary angioplasty (PTCA) in patients with recurrent angina
following coronary artery bypass grafting. The study looked at 112 branches
associated with graft failure, excluding new lesions in the native coronary
artery (NCA). Chronic total occlusion (CTO) was observed in 50% of NCA (56/112)
and in 68% of the grafts (76/112). Thirty-three branches (29%) showed CTO in both
NCA and the graft. The overall success rate was 86% (96/112). The success rate on
NCA was 98% (44/45) in non-CTO, while in CTO it was significantly lower at 62%
(18/29). As to grafts, the success rate was 94% (32/34) in non-CTO, while it was
50% (2/4) in CTO. These characteristics, with respect to lesion morphology and
the prevalence of CTO, exerted an influence on the selection of the access
vessels for revascularization. Early outcome depended on the result of treatment
of CTO.
PMID- 9766707
TI - Effect of chronic neutral endopeptidase inhibition on cardiac hypertrophy after
experimental myocardial infarction.
AB - Candoxatril is an inhibitor of neutral endopeptidase, a membrane-bound enzyme
that degrades atrial natriuretic peptide. The effects of candoxatril on
hemodynamic parameters and cardiovascular hypertrophy were evaluated in the rat
model of myocardial infarction. Myocardial infarction was induced by left
coronary artery ligation in rats and they were treated either with candoxatril
(10mg/kg per day) or a vehicle for up to 4 weeks. Systolic blood pressure and
body weight did not change for up to 4 weeks between the 2 groups. At the end of
treatment, hemodynamic parameters were measured, and then plasma, heart, lungs
and kidneys were collected. Kidney neutral endopeptidase, as measured by the
quantitative autoradiographic method, was significantly inhibited in candoxatril
treated rats compared with that in controls (66.6+/-3.2% of control, p<0.001). On
the contrary, there were no significant differences in right atrial pressure,
left ventricular end-diastolic pressure, systemic pressure, and plasma level of
atrial natriuretic peptide between the 2 groups. There were also no significant
differences in cardiac weight and lung weight. These data indicate that
inhibition of neutral endopeptidase by candoxatril at a dose of 10 mg/kg per day
did not oppose cardiac hypertrophy in the rat model of myocardial infarction in
spite of significant neutral endopeptidase inhibition.
PMID- 9766709
TI - Chronic degenerative changes in the myocardium supplied by bridged coronary
arteries in eight postmortem samples.
AB - In humans, the coronary arteries course not only subepicardially but also
intramyocardially. The intramyocardial course of the coronary artery is reported
to lead to acute ischemic heart disease and, as well, it may be symptomless. The
aim of this study was to investigate the long-term ischemic effects of bridged
arteries on the myocardium, and was carried out on 8 autopsy hearts with
myocardial bridges and 2 hearts without myocardial bridges. The samples from the
myocardium were examined with light microscopy. In the myocardium supplied by the
bridged arteries, it was observed that there was an increase in the intercellular
connective tissue, which was rich in collagen bundles, lymphocytes, fibroblasts
and macrophages. Compression of the coronary artery by myocardial bridges may
cause chronic degenerative changes, which may remain silent for a long time.
PMID- 9766711
TI - Surgical treatment for Scheie's syndrome (mucopolysaccharidosis type I-S): report
of two cases.
AB - Scheie's syndrome (mucopolysaccharidosis type I-S) is a rare genetic lysosomal
storage disease affecting mucopolysaccharide metabolism, and is known to include
cardiovascular disease. Surgical treatment was carried out in 2 patients with
Scheie's syndrome. Patient 1 was a 56-year-old man with triple-vessel coronary
artery disease, who successfully underwent coronary artery bypass grafting.
Patient 2 was a 52-year-old man with aortic and mitral valve stenosis, who
successfully underwent combined aortic and mitral valve replacement. The
literature on Scheie's syndrome associated with valvular and coronary artery
disease is also reviewed.
PMID- 9766710
TI - Cell cycle of myocytes of cardiac and skeletal muscle in mitochondrial myopathy.
AB - Patients who have mitochondrial myopathy can present with specific pathological
conditions (eg, diabetes mellitus and deafness). A 36-year-old woman presented
with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like
episodes (MELAS). An investigation was conducted into whether the abnormalitiy of
mitochondrial DNA (a T to C transition at position 3271 in the mitochondrial tRNA
[Leu(UUR)] gene) influences nuclear DNA synthesis by cells in the heart, skeletal
muscles, and brain. Myocardium, skeletal muscle, and brain tissues were stained
with hematoxylin-eosin, and Masson trichrome for histopathology. Target nuclei
taken from the myocardial and skeletal muscles and brain tissue were purified
after removing debris by the modified Hedley method. These nuclei were stained
with propidium iodide (PI) for analysis by flow cytometry. The number of nuclei
in the G2M phase was bigger in myocytes of MELAS than in normal myocytes
(Control) (MELAS myocyte: Control myocyte=24.9+/-7.3: 6.1+/-1.6%, p<0.005), but
there was no significant increase in the G2M phase in brain tissue. The G1 phase
was far more reduced in MELAS myocytes and skeletal muscle than in Controls
(MELAS myocyte: Control myocyte=65.8+/-9.1: 88.0+/-3.2%, p<0.005; MELAS skeletal
muscle: Control skeletal muscle=85.1+/-2.2: 90.1+/-3.2%, p<0.05), while there was
no significant decrease of nuclei in the G1 phase in brain tissue. Increased
amount of nuclei in the G2M phase in cardiac myocytes and skeletal muscle cells
compared with that in neurons might depend on the capacity for proliferation and
differentiation of these cells as compared with brain tissue. It was concluded
that the mitochondrial DNA mutation (3271T-to-C) of MELAS may influence the
nuclear DNA synthesis of cells in various tissues depending on their level of
mitotic activity.
PMID- 9766712
TI - Left coronary artery-left ventricle fistula with right coronary artery spasm.
AB - A 72-year-old woman was admitted to our hospital for evaluation of chest pain.
Coronary angiography showed a left coronary artery-left ventricle fistula. An
acetylcholine provocation test induced vasoconstriction of the right but not the
left coronary artery. Her chest pain was not relieved by combined therapy with
isosorbide dinitrate, diltiazem and nicorandil. Because of the coronary spasm,
beta-blockers could not be used. However, her chest pain was relieved after the
administration of a minor tranquilizer. Thus, the patient's chest pain was
unlikely to be associated with either the fistula or the coronary spasm.
PMID- 9766713
TI - Effect of relatively low dose amiodarone therapy on left ventricular function in
patients with ventricular tachyarrhythmias.
AB - The effect of oral amiodarone (AMD) therapy on left ventricular (LV) function was
evaluated retrospectively in Japanese patients with ventricular tachyarrhythmias
and congestive heart failure. Seventeen patients were treated with oral AMD
(maintenance dose 191+/-52mg/day) for more than 12 months. Fractional shortening
(FS) on echocardiography revealed a trend towards an increase in the short-term
(3 months) (p=0.06), but was not significant in the long-term follow-up period
(more than 12 months) after AMD therapy. In 8 patients with 1 episode of
myocardial infarction, FS revealed a trend towards an increase (p=0.09). In all
of the 4 patients with dilated cardiomyopathy whose LV end-diastolic diameter was
increased, FS was decreased in the long-term follow-up. Neither hospitalization
frequency nor New York Heart Association classification were reduced by AMD
therapy. In conclusion,oral AMD therapy did not cause LV function to recover
significantly and could not improve the clinical course in patients with
ventricular tachyarrhythmias. However, if the underlying disease is not
progressive, AMD therapy may improve LV function.
PMID- 9766714
TI - Simultaneous elevation of the levels of circulating monocyte chemoattractant
protein-1 and tissue factor in acute coronary syndromes.
AB - The levels of circulating monocyte chemoattractant protein-1 (MCP-1) and tissue
factor (TF) were examined on admission in 46 consecutive patients with acute
coronary syndromes (ACS) and 30 patients with stable exertional angina (SEA). The
plasma levels of both MCP-1 and TF were higher in the ACS patients than in the
SEA patients (MCP-1: p<0.001; TF: p<0.001). Only the circulating TF level related
to the number of diseased vessels. A positive correlation between plasma MCP-1
and TF levels was found (r=0.476, p<0.001). These results suggest that
circulating MCP-1 plays an important role in the pathogenesis and/or development
of ACS.
PMID- 9766715
TI - Fibrinolytic treatment of pleural infection.
PMID- 9766717
TI - Imaging of acute right lower abdominal quadrant pain.
AB - This article reviews the clinical diagnosis of appendicitis, indications and
options for appendiceal imaging, compares appendiceal CT techniques, and
describes the imaging findings with appendicitis and alternative conditions that
can clinically mimic appendicitis.
PMID- 9766716
TI - Imaging the thyroid.
AB - Thyroid imaging has historically relied heavily on scintigraphy, although, not
surprisingly in view of the superficial position of the gland, ultrasound has
assumed an increasingly prominent role in recent years. The other cross-sectional
imaging modalities can also be useful, and the emergence of new
radiopharmaceuticals and the increasingly central role of fine needle aspiration
cytology have further added to the range of diagnostic techniques available. This
review attempts to summarize the current state of knowledge, and makes some
suggestions for the most efficient use of imaging resources in the investigation
of thyroid disease.
PMID- 9766718
TI - Functional endoscopic sinus surgery (FESS): what radiologists need to know.
AB - The place of coronal computed tomography (CT) in the assessment of patients prior
to functional endoscopic sinus surgery (FESS) is well established. The ability to
accurately correlate radiological and surgical anatomy enhances precision and
safety during FESS. This pictorial essay reviews the conceptual anatomical
framework that forms the basis of FESS.
PMID- 9766720
TI - The clinical effectiveness of the Gianturco oesophageal stent in malignant
oesophageal obstruction.
AB - Between January 1994 and December 1996 72 patients were treated with 76 Gianturco
oesophageal stents for oesophageal obstruction or perforation. The patients were
followed prospectively in order to determine the effectiveness in improving
dysphagia, to establish long term patency, survival times and complications. The
mean dysphagia score prior to stenting was 3, improving to a mean score of 1
after stenting. Swallowing failed to improve in three patients. No serious
complications were seen at stent insertion. Patients tolerated the procedure well
with no complications in 63%. The most frequent immediate complication was chest
pain occurring in 15 patients (21%). This settled in all patients with
appropriate analgesia, however, four patients required long-term pain relief. In
no cases was the chest pain due to perforation. Re-intervention was required in
16.7% of patients, the commonest cause being tumour overgrowth, and this was seen
primarily in patients with long survival. The migration rate was low, despite the
fact that 45 of 76 stents had been placed with the distal end in the stomach.
Only four stents (5.6%) migrated completely, all of which had been deployed
across the cardia. In our series the use of the Gianturco oesophageal stents for
provided effective palliation of malignant oesophageal obstruction.
PMID- 9766719
TI - Computed tomography and positron emission tomography in the pre-operative staging
of oesophageal carcinoma.
AB - Because patients with carcinoma of the oesophagus usually present with advanced
disease and surgery has a high mortality with cure in less than 10% of patients,
pre-operative staging to select appropriate patients is necessary. Computed
tomography (CT) plays an important role in staging but has well recognized
limitations. Positron emission tomography (PET) which provides physiological
information may therefore be a better alternative. OBJECTIVE: To compare the
findings of CT and positron emission tomography (PET) with 2-[18fluorine]-fluoro
2-deoxy-D-glucose (FDG) in the pre-operative staging of oesophageal carcinoma.
MATERIALS AND METHODS: Twenty-five patients with biopsy proven oesophageal cancer
had pre-operative staging using CT and FDG-PET. The studies were read
independently and full histological confirmation was obtained in 19 patients.
Four parameters were studied: the primary tumour, peri-oesophageal lymph nodes,
liver metastases and left gastric lymph nodes. RESULTS: PET visualized all
primary tumours; CT missed one. CT identified 4/8 patients with involved peri
oesophageal nodes and PET 3/8. CT identified 5/9 patients with left gastric
adenopathy and PET 1/9. PET visualized a liver metastasis missed on CT and
appeared to be better in assessing residual tumour. PET did identify distant
metastases not seen on CT in seven patients. CONCLUSIONS: The two techniques are
both effective in showing the primary tumour and about equally sensitive in the
demonstration of peri-oesophageal nodes. PET is probably more sensitive than CT
for the detection of distant metastases.
PMID- 9766722
TI - Rotational digital subtraction carotid angiography: technique and comparison with
static digital subtraction angiography.
AB - Recent advances in angiography equipment have allowed the development of
rotational digital subtraction carotid angiography. We give the first description
of this technique applied to the extracranial carotid circulation, using the
Phillips Integris V3000 release 11. Forty-three patients undergoing conventional
digital subtraction angiography were compared with 63 patients who had rotational
digital subtraction angiography for examination of the extracranial carotid
circulation. The parameters compared were: total procedure time, volume of
contrast injection, number of contrast injections, total data acquisition time,
image quality, radiation dose and patient comfort. There was a reduction in the
total procedure time, improvement in patient comfort, data acquisition time and a
reduction in the number of injections. Conventional DSA may underestimate
stenoses in 65% of cases. There is no significant change in the total volume of
contrast injected. There is, however, an increase in the radiation dose during
data acquisition.
PMID- 9766721
TI - Magnetic resonance imaging of prostate cancer: comparison of image quality using
endorectal and pelvic phased array coils.
AB - OBJECTIVE: To compare endorectal coil (ERC) and pelvic phased array (PPA) coil
magnetic resonance imaging for delineation of the prostate gland and seminal
vesicles. To compare ERC images at different inflation volumes of the ERC air
balloon. MATERIALS AND METHODS: Twenty-one patients underwent T2-weighted
examinations using PPA and ERC. The ERC evaluations were performed at three
balloon inflation volumes (60, 100 and 140 ml). All patients had proven prostate
cancer. Images were analysed for visibility of anatomic structures, gland
distortion, tumour visualization, artefacts (coil flare, coil-related artefact
and rectal movement) and overall image quality. A grading system was used for
each parameter. RESULTS: ERC assessments at increasing balloon inflations showed
equivalent anatomical detail and overall image quality. However, increasing gland
distortion and decreasing coil related flare was found with higher air inflations
(P = 0.13 and P = 0.006, respectively). When compared with ERC images, visibility
of the anterior gland and neurovascular bundles was better with the PPA coil (P =
0.0001 and 0.002, respectively). The overall image quality was superior with the
PPA coil (P = 0.0001). However, no significant difference in visualization of
tumour or delineation of tumour extent was observed between the two techniques.
CONCLUSIONS: PPA imaging of the prostate gland provides images of superior
quality compared with the ERC. This is mainly due to fewer artefacts with the PPA
coil and improved anterior gland visibility. When ERC is used, air inflation to
at least 100 ml reduces coil flare artefact.
PMID- 9766723
TI - The therapeutic impact of lumbar spine MRI on patients with low back and leg
pain.
AB - The influence of lumbar spine magnetic resonance imaging (MRI) on the management
of patients with low back and leg pain, with a clinical diagnosis of neural
compression, has been investigated by a controlled prospective observational
study. The clinical features of the patients at the time of request for MRI have
been compared with the subsequent management in order to define the clinical
indications for lumbar spine MRI. METHODS: Clinical history, physical examination
findings and tests of functional and psychological disability were all recorded
at the time of request for MRI. Following MRI, patients were assessed without
knowledge of the MRI findings and a diagnosis and management plan recorded.
Immediate access to the MRI report and hard copy films was then provided and a
revised diagnosis and management plan made. The clinical features and MRI
findings were compared with the subsequent management. RESULTS: Seventy-two
patients were examined, 65 (90.3%) had leg pain as a predominant feature and
abnormalities in neurological examination were found in 31 (43%). Twenty-three of
48 (47.9%) of patients with a pre MRI management plan of surgery were changed to
conservative management following the MRI. The diagnosis altered in 50 % of cases
with the largest change in diagnosis occurring in 13 patients where MRI did not
confirm the clinical impression of nerve root compression. Seventeen patients
with no abnormality of neurological testing were subsequently treated by surgery
which included all 12 patients treated by spinal fusion. CONCLUSIONS: The major
impact of MRI was to move patients towards conservative treatment. A variety of
features in the history and physical examination as well as MRI findings are
predictors for surgical treatment. The variety of diagnoses and surgical options
available make it difficult to define clear clinical guidelines for the use of
MRI.
PMID- 9766724
TI - Acute right ventricular dilatation: a new helical CT sign of massive pulmonary
embolism.
AB - Acute right heart failure is a principal cause of circulatory collapse and death
in patients with massive pulmonary embolism (PE). The purpose of this study was
to investigate if helical computed tomography (CT) could contribute to the
assessment of the right ventricle (RV) in those with massive PE. Over an 8-month
period 79 helical CT pulmonary angiograms were performed to investigate suspected
PE. Emboli were demonstrated in 28 (35%) patients and seven (9%) were considered
to have had a major thromboembolic event. The CT scans of all patients were
evaluated using parameters derived in the axial plane (maximum minor axis RV and
LV dimensions, RV:LV minor axis ratio and RV wall thickness). Acute right
ventricular dilatation with an RV:LV ratio> 1.5:1 (range 1.6:1-2.3:1, mean 2:1)
was found in all seven patients who had sustained major PE. In the remaining
group of 21 with lesser degrees of embolism no patient had an RV:LV ratio > 1.1:1
(range 0.8-1.1, mean 1.0). To our knowledge, this CT sign has not been described
before. CONCLUSION: Helical CT can identify acute RV dilatation in addition to
making the primary diagnosis in patients with massive PE. This observation may
help identify those at greatest risk of a second fatal event and facilitate
therapeutic strategy.
PMID- 9766725
TI - Hepatic malignant fibrous histiocytoma: CT findings.
AB - Although malignant fibrous histiocytoma represents the most common soft tissue
sarcoma in adults, its origination in visceral organs is very unusual and the
liver is an exceptional site of involvement, with only 22 cases reported in the
last 12 years. This controversial tumour, first described in 1964, probably
originates from undifferentiated mesenchymal cells and has five different
histological subtypes: storiform pleomorphic, myxoid, giant cells, inflammatory
and angiomatoid. We describe herein the rather variable CT findings of three
malignant fibrous histiocytomas of the liver and discuss their differential
diagnosis.
PMID- 9766726
TI - Azygos reflux: a CT sign of cardiac tamponade.
AB - Three patients who were investigated with dynamic contrast medium enhanced
computed tomography (CT) of the thorax were noted to have pericardial effusions
with reflux of contrast medium back along the azygos vein. The diagnosis of
cardiac tamponade was not made clinically, but in each case was suggested from
the CT findings. Confirmation of the diagnosis was made in all three cases, two
patients with echocardiography and one at post mortem. One patient made a rapid
recovery following the insertion of a pericardial drain, another made a temporary
recovery after pericardiocentesis but the third died. Thirty CT scans performed
with similar protocol were reviewed and none of these demonstrated reflux along
the azygos vein. The presence of contrast medium refluxing into the azygos vein
implies significant haemodynamic disturbance, and in the presence of a
pericardial effusion suggests the diagnosis of cardiac tamponade.
PMID- 9766727
TI - Case report: Radiolabelled octreotide scanning as a guide to the management of an
occult carcinoid tumour.
PMID- 9766728
TI - Case report: Small intestinal pseudo-obstruction: an unusual manifestation of
polymyositis.
PMID- 9766729
TI - Radiological investigation of suspected lower limb deep vein thrombosis.
PMID- 9766730
TI - Radiological investigation of suspected lower limb deep vein thrombosis.
PMID- 9766731
TI - Malfunctioning central venous catheters.
PMID- 9766732
TI - Transthoracic needle biopsy.
PMID- 9766733
TI - But what can you do for them?
PMID- 9766734
TI - Growth of preterm infants with cystic periventricular leukomalacia.
AB - Etiology of the high rates of growth failure in children with cerebral palsy (CP)
remains unclear. The purpose of this study was to evaluate the relation between
growth failure in preterm infants with cystic periventricular leukomalacia (CPVL)
and neonatal health complications. The population consisted of all preterm
infants (51) with a gestational age of <33 weeks who were admitted to the
Children's Hospital of Buffalo from 1988 to 1993 and who had CPVL. Out of the 41
survivors with CPVL who were followed, 39 developed CP and 18 developed growth
failure during infancy. At the time of greatest growth failure, the majority
(72%) of infants had signs of undernutrition as defined by the Waterlow (1972)
classification. Oral feeding impairment was the sole risk factor for the
occurrence of growth failure. Undernutrition appears to be important in the
occurrence of growth failure in preterm infants with CPVL and CP.
PMID- 9766736
TI - Sleep EEG and developmental dysphasia.
AB - To determine the relation between developmental dysphasia and EEG anomalies
during sleep, we compared 52 subjects with dysphasia with a control group of 20
children by using the ambulatory EEG method. Whereas 50% of the children with
dysphasia experienced paroxysmal activity (PA), only two of the control group
did. It is likely that paroxysmal abnormalities and language impairment are
related to architectural dysplasia and neuron-migration disturbances. PA is
frequent in subjects with receptive developmental dysphasia and may be the cause
of language deterioration. When the occurrence of paroxysmal abnormalities during
sleep is higher than 8% of total sleep time, we suggest the use of antiepileptic
drugs.
PMID- 9766735
TI - Gangliosides in cerebrospinal fluid in children with autism spectrum disorders.
AB - Gangliosides are sialic acid-containing glycolipids found in all cells,
especially abundant in nerve cells and mainly situated on outer-membrane
surfaces. The aim of this study was to provide data on the concentration of
gangliosides in the CSF of children and adolescents with autism spectrum
disorders (ASD) - 66 with autistic disorder, and 19 with other autism spectrum
disorders. The comparison group consisted of 29 children and adolescents, whose
CSF had been sampled to exclude acute infectious CNS disorder. The concentrations
of the gangliosides GM1, GD1a, GD1b, and GT1b were determined using a
microimmunoaffinity technique. The ASD group had a significantly higher
concentration of ganglioside GM1 compared with the comparison group. The GM1
increase could not be explained as secondary to other clinical factors. Mean
ganglioside levels did not differentiate subgroups with autistic disorder and
those with a more atypical clinical picture, nor subgroups with known medical
disorders and those with idiopathic autism. Altered patterns of gangliosides in
the CNS might reflect important correlates of pathogenesis in autism.
PMID- 9766737
TI - Do hyperactive children have motor organization and/or execution deficits?
AB - Hyperactive children have been described as motorically clumsy. To explore the
validity of this assertion, an experiment using the additive factor method was
designed to examine motor organization and execution in hyperactive children.
Four groups of boys aged 7 to 8 years took part in the study: (1) a pure
hyperactive (HA) group, N=20; (2) a pure conduct-disordered (CD) group, N=18; (3)
a mixed hyperactive/conduct-disordered (HA+CD) group, N=12; (4) a normal (N)
control group, N=22. While the small sample size precluded a definitive
conclusion, the results indicated that neither HA nor CD children showed any
motor organization or execution deficit in a simple sequential key-tapping task.
Given previous findings indicating that hyperactive children show deficits in
more complex motor coordination skills, the generalizability of our negative
results needs to be examined on other more complex tasks.
PMID- 9766738
TI - Aetiological factors and prevalence of severe mental retardation in children in a
Swedish municipality: the possible role of consanguinity.
AB - The prevalence of severe mental retardation (SMR) was studied in one of the 24
suburban municipalities in Stockholm. The study area had a high proportion of non
European nationals. The study population comprised 14138 children born between
1979 and 1992 who resided in this municipality on the census day, 31 December
1995. The total prevalence of SMR was 4.5 per 1000, being 3.7 per 1000 and 5.9
per 1000 in the European and in the non-European population, respectively. The
majority of cases (66%) had a definite prenatal origin. Down syndrome was the
cause in 20%. Six families (10%) had at least two children with SMR. It was
concluded that the prevalence was higher than in previous Swedish studies. Many
cases were attributed to genetic factors. Consanguineous marriages were assumed
to be a factor of importance in the distribution of aetiologies. Demographic
differences between areas in Sweden must be considered when planning habilitation
services.
PMID- 9766739
TI - Hand function in children with cerebral palsy after upper-limb tendon transfer
and muscle release.
AB - Thirty-two children with hand dysfunction due to cerebral palsy were examined
before tendon transfer and muscle release, and 9 months postoperatively. All
children improved their performance regardless of the degree of impaired hand
function. The main advantage of surgery was a more functional position of the
hand with increased wrist extension and forearm supination. There were also
increased functionality of handgrips, grip strength, and dexterity. Impaired
sensibility before surgery did not influence the outcome. Individual goals were
set preoperatively. Individual functional goals outlined before surgery were met
by most children. Children identified as having mild impairments gained new
functional skills related to everyday activity (self-care and leisure), while
children with severely impaired hand function demonstrated enhanced grasping
ability, as well as a better cosmetic appearance.
PMID- 9766741
TI - Saccadic strategies in children with hemianopia.
AB - Multiple hypometric (undershooting) saccades are generally reported as a
compensatory strategy in adults with homonymous hemianopia. However, hypermetric
(overshooting) saccades have been reported to develop spontaneously as a
beneficial strategy in response to predictable targets. We examined the saccades
of 10 children (aged 5 to 16 years) with homonymous hemianopia to determine the
type of compensatory eye-movement strategies employed 6 months to 16 years after
hemianopia onset. Homonymous hemianopia was identified using perimetry and/or
pattern visual evoked potentials and supported with results of neuroimaging. Eye
movements were recorded using bitemporal electrooculography. Saccades were
elicited to a red light source in a semipredictable paradigm. We found that
hypermetria was not a consistent compensatory strategy in our patients. In spite
of the predictability of our paradigm and the long follow-up period, multiple
hypometric saccades into the blind field appeared to be the preferred strategy.
PMID- 9766740
TI - Musculoskeletal modelling in determining the effect of botulinum toxin on the
hamstrings of patients with crouch gait.
AB - This study aimed to determine the effect of hamstring botulinum toxin A (Btx-A)
injection in 10 children with crouch gait in terms of changes in muscle length
and lower-limb kinematics. Before Btx-A injection limb kinematics were recorded.
Maximum hamstring lengths and excursions were calculated by computer modelling of
the lower limb. Data were compared with the averaged hamstring lengths of 10
control children. Hamstrings were defined as short if their length was shorter
than the average maximum length minus one standard deviation. Gait analysis was
repeated 2 weeks after isolated hamstring Btx-A injection. Pre- and postinjection
kinematic data and muscle lengths were then compared. Four of 18 injected limbs
in three subjects had short medial hamstring before injection, none of the
subjects had short lateral hamstrings. Muscle excursion was significantly reduced
in the short and adequate maximum muscle length groups. A significant increase in
the semimembranosus and semitendinosus length in all of the injected limbs was
noted. Only in the short muscle group was a significant increase in muscle
excursion observed. Knee extension improved by 13 degrees in the adequate muscle
length group and by 15.6 degrees in the short muscle length group. Pelvic tilt
and hip flexion increased in both groups non-significantly. Average walking speed
postinjection increased from 0.60 ms(-1) to 0.71 ms(-1). Short hamstrings are
over-diagnosed in crouch gait. Hamstring Btx-A injection in patients with crouch
gait produces significant, repeatable muscle lengthening and improved ambulatory
function.
PMID- 9766742
TI - Acute transverse myelitis in childhood: nine cases and review of the literature.
AB - Acute transverse myelitis (ATM) is a rare disease in childhood and adolescence.
It is characterized by paraplegia with or without sensory symptoms and bladder
dysfunction, and typically manifests itself over a period of hours to 1 week.
This is a report of nine patients who were treated between 1993 and 1996. To
exclude treatable conditions, spinal and cranial MRI with and without contrast
medium, electrophysiologic tests, and CSF examinations are performed as soon as
possible after onset. At present post- or parainfectious inflammation is thought
to be the most frequent cause of ATM. Some causes of ATM can be proved only by
follow-up examination. The most important differential diagnoses are multiple
sclerosis and Guillain-Barre syndrome with its variants. After exclusion of
spinal cord compression, and if specific antibiotic treatment is not possible, a
3-day high-dose i.v. steroid pulse therapy is the most promising treatment.
Prognosis is variable and residual symptoms are common. A controlled multicenter
study is suggested to assess epidemiology, etiology, and prognosis of ATM.
PMID- 9766743
TI - Movement disorders in association with herpes simplex virus encephalitis in
children: a review.
PMID- 9766744
TI - Under-reporting of clinical trials is a well known 'occupational hazard'.
PMID- 9766745
TI - Problems in the classification of CMML--dysplastic versus proliferative type.
AB - The FAB group proposed to distinguish two subgroups of chronic myelomonocytic
leukemia (CMML). Depending on the total leukocyte count, a myelodysplastic type
(MDS-CMML) (< or = 13,000 microl(-1)) was separated from a myeloproliferative
type (MPD-CMML) (> 13,000 microl(-1)). Based on retrospective analyses of 158
patients with CMML, we compared the presenting clinical and hematological
features of both disorders and examined whether the refined classification is
important in terms of prognosis. There were 81 patients with MDS-CMML and 77
patients with MPD-CMML. Median age of patients at diagnosis (70 versus 72 years)
was not different. The sex ratio showed a preponderance of males in the MPD group
(m:f; 2.1:1). Splenomegaly was more common in MPD-CMML (54 versus 30%; P =
0.002). With regard to laboratory findings, patients with MPD-CMML presented with
significantly higher LDH values (medians 295 versus 231 U ml(-1); P = 0.008) and
higher serum deoxythymidine kinase levels (medians 150 versus 41 U microl(-1); P
= 0.0025). Except for white blood cell count (WBC), peripheral blood counts were
not different. Median percentage of bone marrow blasts was 9% and cumulative
survival rates were similar in both disorders. Two years after diagnosis,
actuarial survival for patients with MPD-CMML was 33%, as compared to 50% for
patients with MDS-CMML (P = 0.31). The probability of transformation to AML was
higher in MDS-CMML (32 versus 17% after 5 years), but this difference also did
not reach statistical significance. The survival of patients with MDS-CMML was
similar to that of other MDS patients (RAEB) who had corresponding medullary
blast counts. Using the Dusseldorf-score, we could define two risk groups within
MDS-CMML with a median survial of 12 versus 40 months (P = 0.001). None of the
known scoring systems could define risk groups within the MPD-CMML group. In
summary, these data suggest that MDS-CMML and MPD-CMML are clinically
distinguishing conditions, but the separation provides little prognostic
information. Further studies are needed to clarify whether response to therapy is
different in MDS-CMML and MPD-CMML.
PMID- 9766746
TI - The classification of chronic myelomonocytic leukaemia.
PMID- 9766747
TI - Interferon-alpha for the treatment of elderly patients with chronic myeloid
leukaemia.
AB - The present retrospective analysis is based on data of 213 patients with chronic
myeloid leukaemia (CML). They were treated with interferon (IFN)alpha-2C
(Berofor) at daily doses of 3.5 MU subcutaneously (s.c.), alone or in combination
with low-dose ara-C or hydroxyurea, according to four consecutive studies of the
Austrian CML Study Group. Comparisons were made between 41 patients aged > or =
60 years and 172 younger patients. The elderly patients (median: 64 years; range:
60-73) showed similar pretreatment characteristics compared with the younger
group, but included a higher percentage of Sokal Stage three (51 vs 20%). Median
observation periods were similar (38 vs 39 months), whereas the duration of
IFNalpha treatment was shorter in the elderly group (median 57 vs 42 weeks). The
rate of overall haematological responses (73 vs 78%) and complete haematological
response (44 vs 54%), was similar in both cohorts. Differences seen in partial (5
vs 12%) and complete cytogenetic response (10 vs 13%), were not statistically
significant, but a tendency in favour of the younger cohort had to be noted.
Summing up, in elderly patients acceptable rates of haematological and cytogentic
response can be expected after treatment with IFNalpha alone or in combination
with LD ara-C or HU.
PMID- 9766748
TI - Cytogenetic clonality analysis in monosomy 7 associated with juvenile
myelomonocytic leukemia: clonality in B and NK cells, but not in T cells.
AB - It remains unclear which lymphoid lineages are involved in juvenile
myelomonocytic leukemia (JMML). We report a JMML patient who acquired monosomy 7
after intensive chemotherapy. In this case, the expression of monosomy 7 was
analyzed in T, B and natural killer (NK) cells highly purified from peripheral
blood mononuclear cells of the patient. The fluorescence in situ hybridization
method revealed the expression of monosomy 7 in B cells, but not T cells. Half of
the NK cells expressed monosomy 7; when NK cells were divided into CD2- and CD2+
populations, this abnormality was positive in 91.1% of CD2- NK cells but in only
14.7% of CD2+ NK cells. These results suggest that, in this JMML patient who
acquired monosomy 7 after intensive chemotherapy, B cells and half of NK cells,
but not T cells, have monosomy 7.
PMID- 9766749
TI - Hemophagocytic syndrome associated with hematological neoplasias.
AB - Hemophagocytic syndrome (HPS) is a reactive process that complicates several
diseases including hematological neoplasias (HN). It has been suggested that HPS
may be a negative prognosis factor for neoplastic diseases. In this retrospective
analysis, 13 cases with HPS associated to HN were compared with two age, sex,
diagnosis, disease stage and treatment matched controls in order to determine the
impact of this syndrome on the survival. Cases with HPS were adult patients with
a male:female ratio of 1:1 and their clinical picture was characterized by fever,
lymphadenopathy, hepatosplenomegaly, and pancytopenia. Median survival since HN
diagnosis was 7 and 48 months for the HPS and control groups, respectively (P =
0.0001). In ten patients who died, median survival after HPS presentation was 1
month. These results suggest that the presence of HPS is a negative prognosis
factor in patients with HN. Due to its high mortality rate, an individualized,
early, and intensive chemotherapeutic regimen may be required for HN complicated
with this syndrome.
PMID- 9766750
TI - c-myc locus amplification and the acquisition of trisomy 8 in the evolution of
chronic myeloid leukaemia.
AB - The biological progression of chronic myeloid leukaemia is often associated with
secondary cytogenetic abnormalities but the molecular mechanisms underlying this
progression are poorly understood. This study explores the association of c-myc
gene amplification with the progression of chronic myeloid leukaemia in fourteen
individuals. Three of these cases showed amplification of c-myc during the course
of their disease. Cytogenetic and molecular analysis of serial samples from some
patients suggested the successive expansion of distinct clones of malignant
cells. Our findings also suggest that trisomy 8 and locus amplification could
represent alternative mechanisms for increasing c-myc gene dosage.
PMID- 9766751
TI - Introduction of a normal retinoblastoma (Rb) gene into Rb-deficient
lymphoblastoid cells delays tumorigenicity in immunodefective mice.
AB - Inactivation of the Rb susceptibility gene occurs in various human cancers and
has been associated with tumorigenicity. Rb gene is inactivated in 30% of acute
leukaemias. The effect of Rb protein expression was assessed in the
lymphoblastoid cell line IM-9 defective for Rb protein, after stable transfection
with a wild-type Rb gene. The Rb transgene was under the control of the MoMuLv
LTR. Protein expression by the transduced cells was confirmed by Western blot and
flow cytometry analyses. Compared to the parental cell line, growth rate remained
unchanged in the Rb transfected clones. In SCID mice however, tumor formation
originating from these clones was delayed. The current data suggest therefore
that, in this Rb-defective haematopoietic cell line, Rb expression correlates
with reduced tumorigenicity but not with reduced growth rate.
PMID- 9766752
TI - Drug-activated multiple pathways of defensin mRNA regulation in HL-60 cells are
defined by reversed roles of participating protein kinases.
AB - Defensin transcription in HL-60 promyelocytic leukemia cells is greatly enhanced
during retinoic acid (RA)-induced differentiation. We have probed this regulatory
pathway by selective modulation of various kinase activities. Induction was
potentiated by elevated cAMP and attenuated by protein kinase C inhibition,
entirely correlated to enhanced or blocked morphological differentiation,
respectively. Yet, defensin mRNA was also induced in undifferentiated HL-60
cells, but not in others, by cAMP alone. By contrast, modulators that cooperated
with RA had adverse effects on the normal capacity of dimethyl sulfoxide to up
regulate these transcripts as well. Thus, defensin mRNA accumulation can be
selectively uncoupled from maturation stage; and transcript levels may be
regulated by multiple pathways, each independently acted upon by different
chemical inducers.
PMID- 9766753
TI - Growth-inhibitory effects of transforming growth factor-beta 1 on myeloid
leukemia cell lines.
AB - Transforming growth factor-beta1 is a pleiotropic cytokine involved in a variety
of biological processes in both transformed and normal cells, including
regulation of cellular proliferation and differentiation; its predominant action
on hematopoietic cells is to inhibit cell growth. We used growth factor-dependent
cell lines to assess TGF-beta1 effects on human myeloid leukemia cell growth.
While four lines were completely or predominantly resistant, TGF-beta1 inhibited
effectively, albeit to various extents, the growth of 12 other cell lines. This
effect was dose dependent and specific, because a neutralizing anti-TGF-beta1
antibody prevented TGF-beta1-induced growth suppression. In the present system,
basic fibroblast growth factor, known as an antagonist of TGF-beta1 counteracting
its inhibitory effects, did not abrogate the suppressive effects of TGF-beta1.
Other growth-stimulatory cytokines negated the TGF-beta1-induced inhibition in
several cell lines, again to various extents. When proliferation was enhanced by
growth-promoting cytokines (e.g. granulocyte-macrophage colony-stimulating
factor, GM-CSF, stem cell factor, SCF, or PIXY-321), some previously TGF-beta1
sensitive cell lines acquired cellular resistance toward TGF-beta1-mediated
growth suppression, whereas four other cell lines remained susceptible to TGF
beta1 growth inhibition despite possible counteraction by other cytokines. Thus,
three growth response patterns to TGF-beta1 were seen: (1) constitutive
resistance; (2) factor-dependent relative resistance; and (3) sensitivity to
growth inhibition indifferent to counteracting cytokines. In the latter case, TGF
beta1 did not downregulate expression of one specific growth factor receptor.
These studies indicate that human myeloid leukemia cells, represented here by
leukemia cell lines as model systems, exhibit heterogeneous growth responses to
TGF-beta1; its inhibitory effects can be modulated or completely alleviated by
positive antagonistic cytokines. The availability of TGF-beta1-susceptible and
refractory cell lines allows for detailed investigations on the mechanisms of
these regulatory pathways, the nature of TGF-beta1-resistance, and the possible
contribution of acquired TGF-beta1-resistance to disease progression.
PMID- 9766754
TI - Divergent effect of taxol on proliferation, apoptosis and nitric oxide production
in MHH225 CD34 positive and U937 CD34 negative human leukaemia cells.
AB - Paclitaxel (Taxol) has been shown to be clinically effective in treatment of
patients with breast and ovarian cancer. It has also shown promising results in
various other solid tumours. Paclitaxel has induced apoptosis in the G2/M phase
of the cell cycle in both HL-60 and U937 human leukaemia cells. A recent study
has shown a dose-dependent cytotoxicity for both taxanes: paclitaxel (taxol) and
docetaxel (Taxotere) on fresh leukaemia cells in primary culture from 16 ALL and
four AML patients and proposed their use in treatment of acute leukaemia
patients. AML is a heterogeneous disease in which malignant transformation and
disease progression occur at the level of CD34 positive cells. Also, the multi
drug resistance gene product, P-glycoprotein is expressed only in CD34 positive
AML cells. Therefore, an in vitro evaluation of the efficacy of paclitaxel, a P
glycoprotein substrate, in CD34 positive AML cells is warranted before
considering its clinical use in acute leukaemia patients. Since all in vitro
studies of paclitaxel reported so far have involved only CD34 negative (HL-60,
U937, K562) human AML cells, the aim of the present study was to evaluate
paclitaxel efficacy against CD34 positive AML cells. The IC50 of paclitaxel for
apoptosis was significantly higher in MHH225 CD34 positive cells (12 +/- 2
microM) than in U937 CD34 negative cells (1.7 +/- 0.2 microM), P < 0.001.
Paclitaxel has a significantly weaker cytotoxic effect on CD34 positive AML
cells. One log higher concentration of paclitaxel was required in MHH225 CD34
positive AML cells to achieve the same apoptosis level achieved in U937 CD34
negative leukaemia cells. Also, at the high concentration achievable in vivo: 10
microM paclitaxel, only half the MHH225 CD34 positive AML cells were apoptotic
versus 72% of U937 CD34 negative leukaemia cells. Clearly, paclitaxel has only
weak or modest in vitro efficacy compared with several conventional anti
leukaemia drugs used in AML treatment. The present results support the poor level
of in vivo induction of apoptosis achieved during a phase I clinical study with
paclitaxel therapy in 26 leukaemia patients. Also, the present results have shown
a significant increase in nitric oxide production during paclitaxel-induced
apoptosis in U937 monocytic leukaemia cells, confirming the vital role of nitric
oxide in mediating paclitaxel-induced apoptosis by monocytic cells. In
conclusion, the present study has demonstrated a clear difference between the
effect of paclitaxel on CD34 negative and CD34 positive AML cells. Given its poor
performance in the phase I clinical study of 26 acute leukaemia patients and the
present weak in vitro cytotoxic effect, it is unlikely that paclitaxel will have
a role in the treatment of acute leukaemia. Also, the present study emphasises
the need to use CD34 positive AML cells such as MHH225 rather than the unsuitable
lineage-specific CD34 negative cells such as HL-60 or U937 for in vitro pre
clinical screening of potential novel effective anti-leukaemia agents.
PMID- 9766755
TI - T lymphocytes from Sezary syndrome patients express beta1 integrins whose beta(1
6)-branched N-linked oligosaccharides reflect their adhesive capacity.
AB - Sezary syndrome (Sz), characterized by slowly progressing clonal proliferation of
CD4+, CD45 RO+ T cells, has several forms that are distinguished according to the
epidermotropic properties of the pathological cells. In a recent paper (Derappe
C, Haentjens G, Lemaire S, Feugeas JP, Lebbe C, Pasqualetto V, Bussel A, Aubery
M, Neel D. Leukemia 1996;10:138), we observed that T lymphocytes from most of the
Sezary patients [Szbeta(1-6)+] expressed high levels of beta(1-6)-GlcNAc-branched
N-linked oligosaccharides while T lymphocytes from other patients [Szbeta(1-6)-]
did not. Because this observation suggests the possibility of two forms of Sz,
distinguished according to the expression rate of these glycans, we looked for a
possible relationship between this expression rate and T-cell adhesiveness. Using
an original protocol (Braut-Boucher F, Pichon J, Rat P, Adolphe M, Aubery M, Font
J. J Immunol Methods 1995;178:41), we observed that T lymphocytes obtained from
the Szbeta(1-6)+ patients adhered less to normal keratinocyte monolayers than T
lymphocytes from Szbeta(1-6)- patients and normal donors. As assessed by FACS
analysis, all the integrin-subunits studied were more expressed on Szbeta(1-6)-,
especially alpha4, alpha5, beta1 and beta2, than on Szbeta(1-6)+ and normal
lymphocytes. Although these results suggest that beta1- and beta2-integrin
expression is involved in the adhesive properties of these T-cells, other
factors, such as glycosylation, may also contribute. To demonstrate this
possibility, we sought the presence of beta(1-6)-GlcNAc-branched N-linked
oligosaccharides on beta1 integrins expressed by T lymphocytes from Sz patients.
Immunoblot experiments, performed using the specific lectin from Phaseolus
vulgaris (Leukoagglutinin form), showed that only the beta1 integrin subunit
expressed by T lymphocytes from Szbeta(1-6)+ patients carried these glycans,
supporting the concept of the involvement of T-cell glycosylation in the
evolution of Sz.
PMID- 9766756
TI - Differential adhesiveness between blood and marrow leukemic cells having similar
pattern of VLA adhesion molecule expression.
AB - Functional adhesion of blood and marrow leukemic cells from 14 acute myeloid
leukemia patients presenting with hyperleukocytosis was evaluated by performing
cytoadhesion assays on purified (extracellular matrix proteins) and non-purified
supports (MRC5 fibroblastic cell line). Results, in 30-min chromium release
assay, show a mean +/- S.D. adhesion to fibronectin, collagen, and laminin
respectively of 30 +/- 17%, 20 +/- 13%, 25 +/- 17% for blood leukemic cells and
18 +/- 11%, 11 +/- 10%, 11 +/- 8% for marrow leukemic cells. These differences
between blood and marrow cells were statistically significant (respectively P =
0.005, P = 0.01 and P = 0.002), while no difference was noted regarding adhesion
to non-purified supports. The higher adhesion of blood blast cells to purified
supports was observed regardless of CD34 expression. No significant difference
was observed in the expression of cell surface VLA-molecules (CD29, CD49b, CD49d,
CD49e, CD49f) between blood and marrow blast cells. The addition of GM-CSF or G
CSF induced increased adhesion of marrow blasts and decreased adhesion of blood
blasts leading to a loss of the difference between blood and marrow cells. In a
60-min chromium release assay, marrow blasts adhered even more than blood
leukemic cells to fibronectin. In contrast, marrow blasts from 'aleukemic' acute
myeloid leukemia patients did not show any modification regarding their adhesion
to extracellular matrix proteins when co-cultured with growth factors.
PMID- 9766757
TI - Trisomy 5 in two cases of acute monocytic leukemia with hyperdiploid clones.
AB - Although numerical chromosomal aberrations are commonly seen in acute myeloid
leukemia (AML), trisomy 5 (+ 5) is very rarely detected. We report two patients,
both of whom suffered from acute monocytic leukemia, in which + 5 was found in
hyperdiploid clones. A review of the English literature shows 17 additional cases
of AML with + 5 in at least one of the abnormal clones, making a total of 19 such
cases including ours. Trisomy 5 has been reported in all FAB subtypes of AML
except acute promyelocytic leukemia. In the 19 cases identified in this report, +
5 was found in association with other numerical changes (four cases), structural
changes (five cases) or both (eight cases). Trisomy 5 as a sole karyotypic
abnormality was exceedingly rare (two cases). Its biologic and prognostic
significance remains to be determined.
PMID- 9766758
TI - Abnormal expression of the Wilms' tumor gene WT1 in juvenile chronic myeloid
leukemia and infantile monosomy 7 syndrome.
PMID- 9766759
TI - Orphanages: an idea whose time has come again?
PMID- 9766760
TI - Age-associated testosterone decline in men: clinical issues for psychiatry.
AB - OBJECTIVE: The author summarizes current knowledge about the diagnosis and
treatment of testosterone decline in healthy aging men and the associated
clinical issues for psychiatry. METHOD: A MEDLINE search was conducted in which
the search terms "male climacteric," "male menopause," "andropause," "viropause,"
"low-testosterone syndrome," and "testosterone replacement therapy" were used.
Literature published before 1966 was identified by reviewing the reference lists
of later publications. RESULTS: Manifestations of testosterone deficiency have
included depression, anxiety, irritability, insomnia, weakness, diminished
libido, impotence, poor memory, reduced muscle and bone mass, and diminished
sexual body hair. Although testosterone levels decline with age, there is great
interindividual variability, and the connection between serum testosterone levels
and clinical psychiatric signs and symptoms is not clear-cut, since other
hormonal changes are implicated as well. Testosterone replacement therapy may
offer hypogonadal men benefit, but long-term studies on its efficacy and safety
are lacking. Comprehensive biopsychosocial assessment should be a routine part of
the evaluation of complaints of low-testosterone syndrome in men. CONCLUSIONS:
Testosterone decline/deficiency is not a state strictly analogous to female
menopause and may exhibit considerable overlap with primary and other secondary
psychiatric disorders.
PMID- 9766761
TI - The orphans of Eritrea: are orphanages part of the problem or part of the
solution?
AB - OBJECTIVE: This study compared the mental health and cognitive development of 9-
to 12-year-old Eritrean war orphans living in two orphanages that differed
qualitatively in patterns of staff interaction and styles of child care
management. METHOD: The directors and several child care workers at each
institution were asked to complete staff organization and child management
questionnaires. The psychological state of 40 orphans at each institution was
evaluated by comparing their behavioral symptoms and performance on cognitive
measures. RESULTS: Orphans who lived in a setting where the entire staff
participated in decisions affecting the children, and where the children were
encouraged to become self-reliant through personal interactions with staff
members, showed significantly fewer behavioral symptoms of emotional distress
than orphans who lived in a setting where the director made decisions, daily
routines were determined by explicit rules and schedules, and interactions
between staff members and the children were impersonal. CONCLUSIONS: When
orphanages are the only means of survival for war orphans, a group setting where
the staff shares in the responsibilities of child management, is sensitive to the
individuality of the children, and establishes stable personal ties with the
children serves the emotional needs and psychological development of the orphans
more effectively than a group setting that attempts to create a secure
environment through an authoritative style of management with explicit rules and
well-defined schedules.
PMID- 9766762
TI - Dopamine transporter occupancies in the human brain induced by therapeutic doses
of oral methylphenidate.
AB - OBJECTIVE: The therapeutic effects of methylphenidate in the treatment of
attention deficit disorder have been attributed to its ability to increase the
synaptic concentration of dopamine by blocking the dopamine transporters.
However, the levels of dopamine transporter blockade achieved by therapeutic
doses of methylphenidate are not known. This study measured, for the first time,
dopamine transporter occupancy by orally administered methylphenidate in the
human brain and its rate of uptake in the brain. METHOD: Positron emission
tomography (PET) and [11C]cocaine were used to estimate dopamine transporter
occupancies after different doses of oral methylphenidate in seven normal
subjects (mean age=24 years, SD=7). In addition, the pharmacokinetics of oral
methylphenidate were measured in the baboon brain through use of PET and
[11C]methylphenidate administered through an orogastric tube. RESULTS: At 120
minutes after administration, oral methylphenidate produced a dose-dependent
blockade of dopamine transporter; means=12% (SD= 4%) for 5 mg, 40% (SD=12%) for
10 mg, 54% (SD=5%) for 20 mg, 72% (SD=3%) for 40 mg, and 74% (SD=2%) for 60 mg.
The estimated dose of oral methylphenidate required to block 50% of the dopamine
transporter corresponded to 0.25 mg/kg. Oral methylphenidate did not reach peak
concentration in brain until 60 minutes after its administration. CONCLUSIONS:
Oral methylphenidate is very effective in blocking dopamine transporters, and at
the weight-adjusted doses used therapeutically (0.3 to 0.6 mg/kg), it is likely
to occupy more than 50% of the dopamine transporters. The time to reach peak
brain uptake for oral methylphenidate in brain corresponds well with the reported
time course to reach peak behavioral effects.
PMID- 9766763
TI - Serotonin transporter protein gene polymorphism and personality measures in
African American and European American subjects.
AB - OBJECTIVE: The SLC6A4 locus encodes the serotonin transporter, which in turn
mediates the synaptic inactivation of the neurotransmitter serotonin. A
polymorphism located in the 5' promoter region of the gene is associated with
altered transcriptional activity of SLC6A4; an earlier study reported an
association of the polymorphism with anxiety- and depression-related traits,
including harm avoidance and neuroticism. The authors attempted to replicate this
finding. METHOD: They assessed genotype at the SLC6A4 promoter polymorphism, and
an additional polymorphism in intron 2, in 322 American subjects of European and
African ancestry, some with diagnoses of a personality disorder or substance
dependence and some normal comparison subjects. Harm avoidance was measured by
the Tridimensional Personality Questionnaire in all subjects, and neuroticism was
measured by the NEO Five-Factor Inventory in 185 subjects. Allele frequencies in
the groups were compared, and hierarchical multiple regression was used to
examine the correlation of demographic features, psychiatric diagnostic group,
and genotype with harm avoidance and neuroticism scores. RESULTS: Although the
demographic factors and psychiatric diagnoses had effects on harm avoidance and
neuroticism scores, there was no main effect of genotype on these personality
measures. In the context of these overall negative findings, interactions were
observed between sex and promoter system genotype and between race and promoter
system genotype which suggest that the present findings are not wholly
inconsistent with those of the earlier study. CONCLUSIONS: The authors were
unable to replicate the association finding. The specific phenotypic composition
of the groups studied with respect to other behaviors could have influenced
ability to detect association of SLC6A4 polymorphisms with personality measures;
population stratification for this locus is also of potential importance.
PMID- 9766764
TI - Short-term augmentation of fluoxetine with clonazepam in the treatment of
depression: a double-blind study.
AB - OBJECTIVE: Because selective serotonin reuptake inhibitors (SSRIs) require 2-4
weeks to reach efficacy, the authors determined whether clonazepam augmentation
of fluoxetine is superior to fluoxetine alone at the beginning of treatment for
major depression. METHOD: Eighty adult outpatients with major depression who were
rated as "moderately ill" or "markedly ill" on the Clinical Global Impression of
Severity underwent 8 weeks of double-blind, randomized treatment with fluoxetine,
20 mg/day for all patients initially and 40 mg/day if needed after 6 weeks. One
half of these patients received clonazepam, 0.5 mg h.s. adjusted to two tablets
by day 10 if needed, and the remainder received placebo, likewise adjusted.
Clonazepam/placebo was gradually discontinued during days 21-33. Efficacy was
evaluated by means of the Hamilton Depression Rating Scale, the Clinical Global
Impression of Improvement, and a patient rating of global improvement. RESULTS:
The patients taking clonazepam improved significantly more during the first 3
weeks of treatment according to ratings on the Hamilton scale (> or =50%
improvement) and the clinician- and patient-rated global improvement measures
("much" or "very much" improved). Analysis of variance confirmed a significant
effect of clonazepam for average Hamilton depression scores. No serious adverse
events were found in either treatment group. Taper effects appeared modest and
transitory. CONCLUSIONS: Clonazepam augmentation of fluoxetine was superior to
fluoxetine alone in the first 3 weeks of treatment. This strategy may reduce
suffering during early SSRI treatment, may partially suppress SSRI side effects,
may increase compliance, and could possibly reduce the risk of suicide.
PMID- 9766765
TI - Effect of pindolol on onset of action of paroxetine in the treatment of major
depression: intermediate analysis of a double-blind, placebo-controlled trial.
Reseau de Recherche et d'Experimentation Psychopharmacologique.
AB - OBJECTIVE: The purpose of this study was to investigate the effect of pindolol to
accelerate the onset of action of paroxetine in patients suffering from major
depression. METHOD: Patients who met DSM-IV criteria for a nonpsychotic disorder,
who had no previously treated episode of major depression episode, and who had a
score of at least 18 on the 17-item Hamilton Depression Rating Scale were
randomly assigned, for the first 21 days, to treatment with paroxetine (20
mg/day) and either pindolol (5 mg t.i.d.) or placebo. Patients were evaluated
with the Hamilton depression scale, the Montgomery-Asberg Depression Rating
Scale, and Global Clinical Impression (CGI) on days 0 (baseline), 5, 10, 15, 21,
25, 31, 60, 120, and 180. RESULTS: Intermediate analysis of the first month's
results for the first 100 patients (pindolol, N=50; placebo, N=50) was performed.
At day 10 there were more improved patients (defined as patients with a maximum
score of 10 on the Hamilton depression scale) in the pindolol plus paroxetine
group (N=24; 48%) than in the placebo plus paroxetine group (N=13; 26%). At day 5
there was no statistically significant difference, and at day 15 and thereafter,
the differences between the two groups disappeared. Hamilton depression scale
scores were significantly lower on days 5 and 10 for the pindolol plus paroxetine
group (mean=15.7, SD=5.3, and mean=11.7, SD=6.4, respectively) than for the
placebo plus paroxetine group (mean=19, SD=5.9, and mean=14.7, SD=6.8); this was
also true for Montgomery-Asberg depression scale and CGI scores. CONCLUSIONS: The
addition of pindolol to paroxetine treatment significantly accelerates the onset
of therapeutic response in patients suffering from major depression.
Nevertheless, the mechanism (pharmacodynamic or pharmacokinetic) of this
beneficial effect remains unclear.
PMID- 9766766
TI - Association between eye tracking disorder in schizophrenia and poor sensory
integration.
AB - OBJECTIVE: The authors tested the hypothesis that eye tracking disorder in
schizophrenia is associated with neurological signs. METHOD: The subjects were 93
normal comparison subjects and 59 schizophrenic patients. They were evaluated
with the Neurological Evaluation Scale, a standardized rating instrument that
assesses sensory integration, motor coordination, sequencing of complex motor
acts, and other neurological signs. Also, the schizophrenic patients' smooth
pursuit eye movements were tested in response to a 0.3-Hz sinusoidal target by
means of infrared oculography. They were divided into those with (N=18) and
without (N=41) eye tracking disorder by using a previously described method,
which was based on mixture analysis of the distribution of position root mean
square error. RESULTS: The patients with eye tracking disorder had significantly
worse performance than the patients without eye tracking disorder with respect to
sensory integration, and the effect size was moderate to large. In comparison
with the normal subjects, both patient subgroups had significantly worse
performance on all of the Neurological Evaluation Scale subscales. CONCLUSIONS:
Although neurological signs are present generally in schizophrenia, poor sensory
integration is particularly pronounced in patients with eye tracking disorder. A
review of the literature shows that the two abnormalities have strikingly similar
patterns of validators, including 1) familial aggregation, 2) premorbid presence,
3) syndromal specificity, 4) trait status, and 5) association with the deficit
syndrome. Poor sensory integration and eye tracking disorder in schizophrenia may
be various manifestations of a common, underlying pathophysiological process.
PMID- 9766767
TI - Are there sex differences in neuropsychological functions among patients with
schizophrenia?
AB - OBJECTIVE: Studies of sex differences in neuropsychological performance in
schizophrenia report inconsistent results, due in part to methodological
artifacts. The study presented here was specifically designed to examine sex
differences in neuropsychological performance. It was hypothesized that
schizophrenic women would exhibit fewer neuropsychological deficits than
schizophrenic men and that their performance would be more similar to that of
normal women than schizophrenic men's performance would be to that of normal men.
METHOD: Thirty-one outpatients with DSM-III-R-defined schizophrenia were
systematically sampled from an extensive service network serving a large urban
catchment area for seriously mentally ill persons. Twenty-seven normal comparison
subjects were matched within sex on the basis of age, parental socioeconomic
status, ethnicity, and handedness. An extensive neuropsychological test battery
was administered, and multivariate analysis of variance was used to test for the
effects of sex and group and sex-by-group interactions. RESULTS: Male patients
were significantly impaired across all functions in comparison with normal male
subjects and on tests of attention, verbal memory, and executive functions in
comparison with female patients. Female patients performed significantly worse
than female normal comparison subjects only on tests of attention, executive
functions, visual memory, and motor functions. CONCLUSIONS: The findings suggest
that women with schizophrenia may be less vulnerable to particular cognitive
deficits, especially those involving verbal processing, than schizophrenic men.
PMID- 9766768
TI - Concordance for sex and the pseudoautosomal gene hypothesis revisited: no
evidence of increased sex concordance in a nationwide Finnish sample of siblings
with paternally derived schizophrenia.
AB - OBJECTIVE: This study set out to determine, in a homogeneous sample with
nationwide coverage in Finland, whether siblings treated for schizophrenia are
more often of the same sex than expected by chance, and whether this is
especially so when the disorder is transmitted by their fathers. METHOD: Finnish
social and health insurance files as well as hospital discharge registers were
searched for probands with schizophrenia from a birth cohort spanning 30 years.
Nuclear families were identified by cross-linkage with the national birth
register, and the sex distribution observed in multiply affected sibships was
compared with expected distributions by maximum likelihood analysis. RESULTS: In
the subset of multiply affected sibships with one parent who had schizophrenia
(84 fathers and 120 mothers), the observed sex distribution did not deviate from
the expected pattern. However, a small and marginally significant excess of sex
concordance emerged from the total sample of 1,942 sibships in which there were
at least two affected members, irrespective of the parents' affection status.
CONCLUSIONS: The results indicate that no above-chance sex concordance in
sibships multiply affected with paternally transmitted schizophrenia is present
in the genetically homogeneous population of Finland. In view of a virtually
unbiased and complete ascertainment procedure and sample sizes one to two orders
of magnitude larger than those in previous studies, the authors attribute prior
findings of such a concordance to sampling artifacts or chance fluctuations and
finally conclude that except for regional genetic isolates, there is no
epidemiologic evidence that a gene accounting for substantial susceptibility to
schizophrenia in a greater proportion of cases resides in the pseudoautosomal
region of the sex chromosomes.
PMID- 9766769
TI - Common pattern of cortical pathology in childhood-onset and adult-onset
schizophrenia as identified by proton magnetic resonance spectroscopic imaging.
AB - OBJECTIVE: Multislice proton magnetic resonance spectroscopic imaging (1H-MRSI)
permits simultaneous acquisition and mapping of signal intensities of N-acetyl
containing compounds (mainly N-acetylaspartate, NAA), choline-containing
compounds (CHO), and creatine plus phosphocreatine (CRE) from multiple whole
brain slices consisting of small single-volume elements. Previous 1H-MRSI studies
of adult patients with schizophrenia showed small NAA relative signals in the
hippocampal area and in the dorsolateral prefrontal cortex in comparison with
healthy subjects. As part of a program to address the pathophysiological
continuity between childhood-onset and adult-onset schizophrenia, the authors
performed 1H-MRSI of patients with childhood-onset schizophrenia to specifically
test whether the hippocampal area and dorsolateral prefrontal cortex show the
same abnormalities as seen in adult-onset schizophrenia. METHOD: A 1.5-T nuclear
magnetic resonance machine was used to test 14 patients (mean age, 16.4 years)
and 14 comparison subjects. Ratios of areas under the metabolite peaks of the
proton spectra were determined (i.e., NAA/CRE, NAA/CHO, CHO/CRE) for multiple
cortical and subcortical regions. RESULTS: The patients showed significantly
lower NAA/CRE ratios bilaterally in the hippocampal area and the dorsolateral
prefrontal cortex than the comparison subjects. There were no significant
differences in CHO/CRE or in NAA ratios in any other area sampled. CONCLUSIONS:
The present study shows that patients with childhood-onset schizophrenia have
smaller than normal regional NAA relative signals, suggesting neuronal damage or
malfunction in the hippocampal area and dorsolateral prefrontal cortex. These
differences were similar in magnitude to those found in patients with adult-onset
schizophrenia. The present data extend other evidence of a biological continuum
between childhood- and adult-onset schizophrenia.
PMID- 9766770
TI - Lower left temporal lobe MRI volumes in patients with first-episode schizophrenia
compared with psychotic patients with first-episode affective disorder and normal
subjects.
AB - OBJECTIVE: Magnetic resonance imaging (MRI) studies of schizophrenic patients
have revealed structural brain abnormalities, with low volumes of gray matter in
the left posterior superior temporal gyrus and in medial temporal lobe
structures. However, the specificity to schizophrenia and the roles of chronic
morbidity and neuroleptic treatment in these abnormalities remain unclear.
METHOD: Magnetic resonance (1.5-T) scans were obtained from 33 patients with
first-episode psychosis and 18 age-matched normal comparison subjects, all right
handed. Sixteen of the patients were diagnosed with affective disorder and 17
with schizophrenia. RESULTS: Quantitative volumetric analysis showed that the
patients with first-episode schizophrenia had significantly smaller gray matter
volume in the left posterior superior temporal gyrus than did the patients with
first-episode affective psychosis or the comparison subjects, with a significant
left-less-than-right asymmetry. The schizophrenic patients also showed a smaller
gray matter volume of the left posterior amygdala-hippocampal complex than the
comparison subjects. Both the patients with schizophrenia and those with
affective psychosis had significant left-less-than-right asymmetry of the
posterior amygdala-hippocampal complex. CONCLUSIONS: These findings suggest that
temporal lobe abnormalities are present at the first hospitalization for
schizophrenia and that low volume of the left posterior superior temporal gyrus
gray matter is specific to schizophrenia compared with affective disorder.
PMID- 9766772
TI - Latent class analysis of lifetime depressive symptoms in the national comorbidity
survey.
AB - OBJECTIVE: Although clinical trials have documented the importance of identifying
individuals with major depression with atypical features, there are fewer
epidemiological data. In a prior report, the authors used latent class analysis
(LCA) to identify a distinctive atypical depressive subtype; they sought to
replicate that finding in the current study. METHOD: Using the National
Comorbidity Survey data, the authors applied LCA to 14 DSM-III-R major depressive
symptoms in the participants' lifetime worst episodes (N=2,836). Validators of
class membership included depressive disorder characteristics, syndrome
consequences, demography, comorbidity, personality/attitudes, and parental
psychiatric history. RESULTS: The best-fitting LCA solution had six classes. Four
were combinations of atypicality and severity: severe atypical, mild atypical,
severe typical, and mild typical. Syndrome severity (severe atypical and typical
versus mild atypical and typical classes) was associated with a pronounced
pattern of more and longer episodes, worse syndrome consequences, increased
psychiatric comorbidity, more deviant personality and attitudes, and parental
alcohol/drug use disorder. Syndrome atypicality (severe and mild atypical versus
severe and mild typical classes) was associated with decreased syndrome
consequences, comorbid conduct disorder and social phobia, higher interpersonal
dependency and lower self-esteem, and parental alcohol/drug use disorder.
CONCLUSIONS: As in prior reports, the atypical subtype of depression can be
identified in epidemiological samples and, like typical depression, exists in
mild and severe variants. Atypical depressive subtypes were characterized by
several distinctive features. However, the correspondence between
epidemiologically derived typologies of atypical depression and DSM-IV major
depression with atypical features is not yet known.
PMID- 9766771
TI - Relationship between type of insurance and care during the early course of
psychosis.
AB - OBJECTIVE: Little is known about the relationship between insurance and care in
the early course of psychosis. This study explored the insurance status of first
admission psychotic patients and the relationship between type of insurance and
care received up to this admission. METHOD: Data are from the Suffolk County
Mental Health Project, an epidemiologic study of first-admission psychosis. Data
on insurance status (N=525) were pooled from hospital records, respondents, and
significant others. Logistic regression analysis, controlling for key background
variables and diagnosis, was used to study the relationship between insurance and
care. RESULTS: At first admission, 233 (44%) of the patients had no insurance, 78
(15%) had Medicaid or Medicare, 203 (39%) had private insurance, eight (1.5%)
were insured by the Veterans Administration, and the insurance status of three
(1.5%) was unknown. Having private insurance increased the likelihood of having
received previous mental health treatment (psychotherapy specifically), being
admitted voluntarily, being hospitalized in a community hospital rather than a
public hospital, and being hospitalized within 3 months of onset of psychosis.
Having Medicaid/Medicare increased the likelihood of receiving nonantipsychotic
medication before this hospitalization, admission to a community hospital rather
than a public hospital, having received previous mental health treatment in
general, and voluntary admission. CONCLUSIONS: During the early course of
psychotic illness, many people lack any type of health insurance, and this is
associated with a decreased likelihood of obtaining care before their first
hospital admission.
PMID- 9766773
TI - Lifetime and twelve-month prevalence rates of major depressive episodes and
dysthymia among Chinese Americans in Los Angeles.
AB - OBJECTIVE: The authors' goal was to estimate the lifetime and 12-month rates of
major depressive episodes and dysthymia for Chinese Americans who reside in Los
Angeles. This effort, the Chinese American Psychiatric Epidemiological Study, is
the first large-scale community psychiatric epidemiological study on an Asian
American ethnic group that used DSM-III-R criteria for major depressive episodes
and dysthymia. METHOD: A multi-stage sampling design was used to select
respondents for participation in the survey. The sample included 1,747 adults, 18
65 years of age, who resided in Los Angeles County and who spoke English,
Mandarin, or Cantonese. RESULTS: Approximately 6.9% of the respondents had
experienced an episode of major depression and 5.2% had had dysthymia in their
lifetime. The 12-month rates of depressive episode and dysthymia were 3.4% and
0.9%, respectively. The most consistent correlate of lifetime and 12-month
depressive episode and dysthymia was social stress, measured by past traumatic
events and recent negative life events. CONCLUSIONS: The Chinese American
Psychiatric Epidemiological Study provides a rare opportunity to investigate the
heterogeneity within a single Asian American ethnic group, Chinese Americans, and
to identify the subgroups among Chinese Americans who may be most at risk for
mental health problems.
PMID- 9766774
TI - Psychiatric disorder onset and first treatment contact in the United States and
Ontario.
AB - OBJECTIVE: The authors describe the timing of the first treatment contact
following new-onset DSM-III-R mood, anxiety, and addictive disorders in community
samples from the United States and Ontario, Canada, before and after passage of
the Ontario Health Insurance Plan. METHOD: The authors drew data from the
National Comorbidity Survey (NCS) (N=8,098) and the mental health supplement to
the Ontario Health Survey (OHS) (N= 9,953). They assessed psychiatric disorders
with a modified version of the Composite International Diagnostic Interview; they
also assessed retrospectively age at disorder onset and first treatment contact.
They used the Kaplan-Meier method to generate time-to-treatment curves and
survival analysis to compare time-to-treatment intervals across the two surveys.
RESULTS: The overall time-to-treatment curves revealed substantial differences
between disorders that were consistent across the two surveys. In both surveys,
panic disorder had the highest probability of first-year treatment (NCS, 65.6%;
OHS supplement, 52.6%), while phobia (NCS, 12.0%; OHS supplement: 6.5%) and
addictive disorders (NCS, 6.4%; OHS supplement, 4.2%) had the lowest in both
surveys. Retrospective subgroup analysis suggests that before the passage of the
Ontario public insurance plan, the likelihood of receiving treatment in the year
of disorder onset was greater in Ontario than in the United States but that this
relationship reversed following passage of the Ontario plan. During this period,
the authors observed no significant between-country differences in the
probability of prompt treatment of adults with 12 or fewer years of education.
CONCLUSIONS: These results challenge the assumption that the universal health
insurance plan in Ontario promotes greater access to mental health services than
is available in the United States for vulnerable groups. Marked differences
between disorders in the speed to first treatment suggest that in both countries,
clinical factors play an important role in the timing of the initial decision to
seek treatment.
PMID- 9766775
TI - Interrater agreement among psychiatrist in psychiatric emergency assessments.
AB - OBJECTIVE: The authors' purpose in this study was to investigate the interrater
agreement among psychiatrists in psychiatric emergency service settings. The
interrater reliability of many of the key concepts in psychiatric emergency
service settings has not been studied. METHOD: Videotapes of 30 psychiatric
emergency service patient assessment interviews conducted by psychiatrists were
shown to eight experienced psychiatric emergency service psychiatrists. The eight
psychiatrists rated each videotape on dimensions such as severity of depression
and psychosis and recommended a disposition for each patient. Interrater
reliability was then explored. RESULTS: The level of agreement (intraclass
correlation coefficient) among the reviewing psychiatrists was higher for
psychosis and substance abuse but lower for psychopathology, impulse control
problems, danger to self, and disposition. The reviewers' disposition
recommendations did not match well with the assessing psychiatrist's actual
disposition, but comparisons with actual practice should be considered only
suggestive. CONCLUSIONS: Psychiatric emergency service assessments need
improvement. This may be accomplished by exploring the underlying structure of
psychiatric emergency service concepts, the creation and validation of structured
assessment tools, and the creation of practice guidelines.
PMID- 9766776
TI - Intensive community-focused treatment of veterans with dual diagnoses.
PMID- 9766777
TI - Rapid cycling in women and men with bipolar manic-depressive disorders.
AB - OBJECTIVE: This study investigated risks for rapid cycling, as defined by DSM-IV,
in women and men with bipolar disorders. METHOD: The results of 10 studies with a
total of 2,057 bipolar patients were meta-analyzed by pooled contingency methods.
RESULTS: The proportions of women and men among rapid-cycling cases averaged 72%
and 28%, respectively, but the risk of rapid cycling was inconsistently more
frequent among women (29.6%) than among men (16.5%). The mean number of episodes
per year was much higher in rapid-cycling patients before and during lithium
treatment but was similar in rapid-cycling men and women. CONCLUSIONS: Rapid
cycling was only moderately, and inconsistently, more common in bipolar women
than men.
PMID- 9766778
TI - Sex differences in neuropsychological functioning of first-episode and
chronically ill schizophrenic patients.
AB - OBJECTIVE: The purpose of this study was to determine whether men and women with
schizophrenia demonstrate differences in cognitive abilities. METHOD: Two cohorts
of patients with schizophrenia, an acute first-episode and a chronically
hospitalized group, were evaluated with a neuropsychological battery and compared
with a normal group of subjects. RESULTS: After adjustment for age, age at onset,
and premorbid IQ, male chronic patients performed worse than female chronic
patients on measures of visual memory. These differences were eliminated after
control for symptom severity. No other differences were found in cognitive
function between men and women in either cohort. CONCLUSIONS: Sex differences in
cognitive function in schizophrenic patients are not robust findings.
PMID- 9766779
TI - Dopamine D2 receptor density and personal detachment in healthy subjects.
AB - OBJECTIVE: The purpose of this study was to examine the relationship between the
personality trait involving personal detachment and dopamine D2 receptor specific
binding in healthy subjects. METHOD: Eighteen adult subjects completed the
Karolinska Scales of Personality and the Tridimensional Personality Questionnaire
and participated in a study that used [11C]raclopride positron emission
tomography (PET) to quantify striatal D2 receptor binding. RESULTS: A significant
relationship was found between D2 receptor specific binding and detachment scores
on the Karolinska Scales of Personality but not between D2 receptor specific
binding and attachment scores on the Tridimensional Personality Questionnaire. In
an exploratory analysis, the authors found a significant relationship between
binding and the sentimentality cluster on the Tridimensional Personality
Questionnaire but on no other personality clusters scores on the Tridimensional
Personality Questionnaire or Karolinska Scales of Personality. CONCLUSIONS: These
findings replicate those of a recent report that personal detachment scores on
the Karolinska Scales of Personality are related to dopamine D2 receptor density
and extends this finding by suggesting that the relationship is relatively
specific to the trait defined by the Karolinska Scales of Personality and does
not generalize to other forms of detachment.
PMID- 9766780
TI - Six-year outcome for cognitive behavioral treatment of residual symptoms in major
depression.
AB - OBJECTIVE: The authors' goal was to determine whether cognitive behavioral
treatment of residual symptoms of depression might have a significant effect on
relapse rate. METHOD: A 6-year follow-up assessment was conducted of 40 patients
with primary major depressive disorder who had been successfully treated with
antidepressants and were randomly assigned to either cognitive behavioral
treatment of residual symptoms or standard clinical management. RESULTS: Ten of
the patients (50%) in the cognitive behavioral treatment group and 15 (75%) in
the standard clinical management group relapsed. The difference did not attain
statistical significance. When multiple relapses were considered, patients in the
cognitive behavioral treatment group had a significantly lower number of
depressive episodes than those in the standard clinical management group.
Patients responded to the same antidepressant drug used in the index episode; in
two cases (4%), resistance occurred. CONCLUSIONS: The protective effects of
cognitive behavioral treatment that were evident at 4-year follow-up faded
afterward. Cognitive behavioral treatment of residual symptoms, however, improved
the long-term outcome of major depression in terms of total number of episodes
during the follow-up period.
PMID- 9766781
TI - Efficient allocation of patients to treatment cells in clinical trials with more
than two treatment conditions.
AB - OBJECTIVE: Clinical trials generally allocate patients to equal-sized treatment
groups. The authors propose that it may be more efficient to allocate unequal
proportions of the total sample size to treatments when more than two treatments
are being compared. METHOD: This proposal is illustrated with two examples. One
involved a comparison of three treatments and used a dichotomous categorical
outcome. The other involved comparison of three treatments and used a continuous
measure. RESULTS: In both examples, a considerable increase in efficiency was
realized by reducing the number of patients assigned to the placebo cell.
CONCLUSIONS: Unequal allocation of patients to treatments should be considered
when more than two groups are compared.
PMID- 9766782
TI - Olanzapine use in women with antipsychotic-induced hyperprolactinemia.
PMID- 9766783
TI - Extrapyramidal side effects in a patient treated with risperidone plus donepezil.
PMID- 9766784
TI - Symptom exacerbation of vocal tics and other symptoms associated with
streptococcal pharyngitis in a patient with obsessive-compulsive disorder and
tics.
PMID- 9766785
TI - Clonidine treatment for hallucinogen persisting perception disorder.
PMID- 9766786
TI - Treatment of Alzheimer's disease.
PMID- 9766787
TI - Treatment of Alzheimer's disease.
PMID- 9766788
TI - Cognitive behavior therapy for chronic fatigue syndrome.
PMID- 9766789
TI - Treatment of dissociative identity disorder.
PMID- 9766790
TI - Deterioration of olfactory identification abilities in patients with
schizophrenia.
PMID- 9766791
TI - Personality disorder diagnoses.
PMID- 9766792
TI - Sex-related differences in depressed alcoholics.
PMID- 9766793
TI - Effect of recombinant human erythropoietin treatment on circulating reticulated
platelets in uremic patients: association with early improvement in platelet
function.
AB - Recombinant human erythropoietin improves platelet function in uremia through the
correction of anemia, but this effect can be seen also before the hematocrit
rise. We studied 12 hemodialyzed patients (seven men, five women) who received
recombinant human erythropoietin (40 IU kg(-1)i.v., three times weekly) and were
evaluated before treatment and after three doses; 24 control subjects were used.
Platelet aggregation induced by adenosine 5'-diphosphate (ADP), epinephrine,
collagen, arachidonic acid, and ristocetin, and reticulated platelets determined
by flow cytometry after staining with thiazole orange were measured. Platelet
aggregation induced by all the agonists were impaired in uremic patients (P <
0.01), but ADP and ristocetin-induced aggregations improved after treatment (P <
0.01). Hemodialyzed patients had less reticulated platelets than controls (P <
0.01). Reticulated platelets increased after three doses of treatment (P < 0.01).
In conclusion, improvement of platelet function at early stages of recombinant
human erythropoietin treatment may be attributed to the increase in young
platelets detected as reticulated platelets.
PMID- 9766794
TI - Progressive expansion of hypertensive intracerebral hemorrhage by coagulopathy.
AB - To test the hypothesis that an impaired coagulation system facilitates rapid
expansion of hypertensive intracerebral hemorrhage (HICH), coagulation markers
were assayed in plasma and their relations to both the hemorrhage size and its
progressive expansion were analyzed. Ninety patients with HICH were studied. On
admission, plasma samples were taken for the coagulation assay. Hematoma volume
was calculated from a computed tomography (CT) scan and its enlargement was
estimated by comparison to the volume of the hematoma calculated from a second CT
scan taken later within 24 hr. Nine out of 90 patients showed enlargement in
their hematoma size (enlarged hematoma group). Four of the enlarged hematoma
group fell into acute fatal deterioration and died. Plasma levels of both fibrino
peptide A (17.2+/-7.8 vs. 4.0+/-0.6 ng/ml, P < 0.05) and thrombin-antithrombin
complex (21.9+/-3.1 vs. 7.4+/-2.8 ng/ml, not significant) were higher in the
unchanged group than those in the enlarged hematoma group. In the hematoma
enlarged group fibrino-peptide A level did not exceed 10 ng/ml. In the hematoma
unchanged group thrombin-AT-III complex values were positively correlated to
hematoma volume. Thus, the coagulation system seemed to be highly activated
depending on the hemorrhage volume within three hr after ictus in hypertensive
intracerebral hemorrhage patients. When thrombin generation was not sufficient
after bleeding, the hematoma seemed to be progressively enlarged. In conclusion,
plasma levels of the coagulation markers on admission could be useful predictors
of the possible enlargement of hematoma which leads to a poor outcome.
PMID- 9766795
TI - Platelet von Willebrand factor in Hermansky-Pudlak syndrome.
AB - The Hermansky-Pudlak Syndrome (HPS) is an autosomal recessive inherited disorder
characterized by oculocutaneous albinism, tissue accumulation of ceroid pigment,
and a mild to moderate bleeding diathesis attributed to storage-pool deficient
(SPD) platlets. Patients have platelet aggregation and release abnormalities. In
addition, low levels of plasma von Willebrand factor (vWF) antigen in some HPS
patients have been associated with a greater bleeding tendency than would be
predicted from either condition alone. Other HPS patients have severe bleeding
despite normal levels of plasma vWF, suggesting that at least one additional
factor is responsible for their bleeding diathesis. Because platelet vWF levels
have been well correlated with clinical bleeding times in patients with von
Willebrand's disease, we have measured the platelet vWF activity and antigen
levels in 30 HPS patients and have attempted to correlate their clinical bleeding
with these values. The platelet vWF activity levels in patients was significantly
lower than that of normal subjects (P < 0.0001). The patients as a group also had
slightly lower values of plasma vWF activity when compared with normals (P-0.03).
In 11 of the HPS patients, the multimeric structure of plasma vWF showed a
decrease in the high molecular weight multimers and an increase in the low
molecular weight multimers. In correlating the platelet and plasma vWF values
with the bleeding histories, we were not able to show a predictable relationship
in the majority of the patients.
PMID- 9766796
TI - Hematological effects of atypical and Cameroon beta-globin gene haplotypes in
adult sickle cell anemia.
AB - To examine the effects of unusual or atypical beta-globin gene cluster haplotypes
on the hematological features and Hb F levels of sickle cell anemia, we studied
African Americans who had an atypical or Cameroon haplotype chromosome in
association with a typical haplotype. We identified over 20 atypical haplotypes.
The distribution of 5' sub-haplotypes of the atypical chromosomes mirrored the
distribution of common haplotypes in African Americans with sickle cell anemia.
Neither 5' nor 3' subhaplotypes of the atypical chromosomes affected Hb F levels,
packed cell volume, or mean corpuscular volume in individuals with a Benin
chromosome. That the 5' subhaplotype is unaffected might be a consequence of the
small numbers of Senegal 5' subhaplotypes in our sample, the need for linkage of
both 5' and 3' subhaplotypes of any haplotype for an effect on Hb F to be
present, or the likelihood that a normal beta-globin gene contributed the 5'
subhaplotypes of some atypical haplotypes.
PMID- 9766797
TI - Usefulness of a low-dose intravenous immunoglobulin regimen for the treatment of
thrombocytopenia associated with AIDS.
AB - Infection with the human immunodeficiency virus (HIV) frequently is complicated
with thrombocytopenia (HIV-Thr) during all stages of the infection. The
treatments for autoimmune thrombocytopenic purpura (ITP) are used in HIV-Thr;
however, their effects upon the immune status of patients with acquired
immunodeficiency syndrome (AIDS) are unknown. Intravenous immunoglobulin (IVIg)
is used in patients with ITP and HIV-Thr; however, its usefulness in
thrombocytopenic AIDS patients has not been directly addressed. We used a low
dose IVIg regimen (0.04 g/kg per week during five weeks) for the treatment of HIV
Thr complicating AIDS. Thirteen patients received IVIg. We observed a response to
IVIg in 13 patients by the end of week one and in 10 patients by the end of week
five. Long-term response, evaluated three months after stopping IVIg, was present
in four cases. IVIg was well tolerated and no opportunistic infections were
observed during the study period. Compared with previous reports, we used 10% of
the previously proposed dosage with an important decrease in the cost of
treatment. Our results suggest that this low-dose IVIg regimen is a highly
effective, nonexpensive alternative in treating HIV-Thr in AIDS. If sustained
responses can be obtained with a similar low-dose maintenance regimen, IVIg may
be the first choice for the treatment of HIV-Thr in AIDS patients.
PMID- 9766798
TI - Systemic transforming growth factor-beta in patients with bone marrow fibrosis-
pathophysiological implications.
AB - Idiopathic myelofibrosis (IMF) and secondary myelofibrosis (MF) are characterized
by bone marrow (BM) fibrosis, neoangiogenesis, and increased extracellular matrix
(ECM) proteins. These characteristics may be partially attributed to transforming
growth factor beta (TGF-beta), a cytokine produced by monocytes. In
myelofibrosis, monocytes are increased and activated with concomitant up
regulation of intracytoplasmic TGF-beta. We have therefore determined systemic
TGF-beta in patients with either BM fibrosis: IMF, n = 18; MF, n = 16; or without
BM fibrosis: hematologic disorders with normal platelets (n = 31); high platelets
(n = 9); or normal controls (n = 27). Compared with nonfibrosis sera, there was
significant TGF-beta elevation in BM fibrosis sera (P < 0.0001). Most (>80%) of
the TGF-beta is active and belongs to the-beta1 isoform. In situ hybridization
and immunohistochemical analyses in BM biopsy sections showed a marked increase
in TGF-beta1 only in patients with fibrosis. Moreover, TGF-beta protein was
detected mainly in myelomonocytic-like predominant areas. To determine if another
functionally similar cytokine, basic fibroblast growth factor (bFGF), may be
important to BM fibrosis, we quantitated sera levels and found elevation in 57%
compared with 100% elevation for TGF-beta. The data indicate that irrespective of
etiology, systemic TGF-beta is elevated in patients with BM fibrosis. TGF-beta
likely plays an important role in the development of BM fibrosis. The study also
provides a significant parameter for early therapeutic intervention in BM
fibrosis.
PMID- 9766799
TI - Decision-tree approach to the immunophenotype-based prognosis of the B-cell
chronic lymphocytic leukemia.
AB - Use of a nonlinear prediction method, such as machine learning, is a valuable
choice in predicting progression rate of disease when applied to the highly
variable and correlated biological data such as those in patients with chronic
lymphocytic leukemia (CLL). In this work, decision-tree approach to cell
phenotype-based prognosis of CLL was adopted. The panel of 33 (32 different
phenotypic features and serum concentration of sCD23) parameters was
simultaneously presented to the C4.5 decision tree which extracted the most
informative of them and subsequently performed classification of CLL patients
against the modified Rai staging system. It has been shown that substantial
correlation between the percentage of expression of the CD23 molecule on CD19+ B
cells, the level of sCD23, the percentage of CD45RA+, and the absolute number of
CD4CD45RA+RO+ T-cells and the clinical stages, exists. The prediction vector,
composed of their concatenated values, was able to correctly associate 83% of the
cases in the low-risk group (Rai stage 0), 100% of the cases in the intermediate
risk group (Rai stage I and II), and 89% of the cases in the high-risk group (Rai
stage III and IV) of CLL patients. Predictivity of this vector was 100%, 95%, and
89%, respectively. In conclusion, from the described analysis, it may be inferred
that two processes play important roles in the progression rate of CLL:
1.deregulated function of the CD23 gene in B-cells accompanied by the appearance
of its cleaved product sCD23 in the sera; and 2. functionally impaired and
imbalanced CD4 T-cell subpopulations found in the peripheral blood of CLL
patients.
PMID- 9766800
TI - Deficient proliferation of myeloid, erythroid, and multipotent progenitor cells
in long-term marrow cultures from patients with aplastic anemia treated with
immunosuppressive therapy.
AB - By using Dexter-type long-term marrow cultures (D-LTMC), it has been shown
previously that hematopoietic progenitor cells (HPC) from patients with aplastic
anemia (AA) have a deficient proliferation in vitro. The studies reported to
date, however, have focused exclusively on granulomonocytic progenitors and no
information exists on erythroid or multipotent progenitor cells. On the other
hand, in such studies, the input progenitor cell numbers were significantly below
normal levels, thus suggesting that the rapid disappearance of myeloid progenitor
cells from AA D-LTMC could also be due, at least in part, to their reduced number
at culture onset. In the present study, we have followed the kinetics of myeloid,
erythroid, and multipotent progenitors, from 24 AA patients subjected to
immunosuppressive therapy (including patients that achieved complete, partial, or
no remission at all), throughout a seven-week culture period. For analysis, we
grouped all the patients based on their initial content of all three types of
progenitors. Thus, we were able to evaluate separately the kinetics of these
cells in D-LTMC from patients with normal and subnormal levels of progenitor
cells. At the time of marrow sampling, most patients showed decreased levels of
HPC; in fact, only 21%, 8%, and 16% of them showed normal levels of myeloid,
erythroid, and multipotent progenitors, respectively. When cultured in D-LTMC,
HPC from all AA patients analyzed showed a relatively fast disappearance from the
cultures. Indeed, myeloid progenitors could be detected for only six weeks,
whereas erythroid and multipotent progenitors disappeared from the cultures after
two and one weeks of culture, respectively. In contrast, in normal marrow D-LTMC,
myeloid, erythroid, and multipotent progenitors were detected for at least seven,
five, and three weeks, respectively. Such a deficient proliferation was observed
even in cultures of AA patients that contained normal levels of HPC at culture
onset. Interestingly, no correlation was found between HPC proliferation in D
LTMC and response to treatment. Thus, the results of this study indicate the
presence of a functional in vitro deficiency in the hematopoietic system of
patients with AA, including those that achieved partial or complete remission
after immunosuppressive treatment. Furthermore, this work suggests that such a
proliferation deficiency is more pronounced in erythroid and multipotent
progenitors than in their myeloid counterparts.
PMID- 9766801
TI - Mitoxantrone, prednimustine, and vincristine for elderly patients with aggressive
non-Hodgkin's lymphoma.
AB - Elderly patients with intermediate- or high-grade non-Hodgkin's lymphoma have a
worse outcome than those who are younger than 60 years. It has been shown that
aggressive combination chemotherapy is poorly tolerated in older patients
resulting in a subsequent decrease in dose intensity. A phase II trial was
conducted with mitoxantrone, prednimustine, and vincristine (NSO) in this group
of patients. NSO consists of mitoxantrone 12 mg/M2 intravenously on day one,
vincristine 1.4 mg/M2 intravenously on day 1 (maximum dose of two mg), and
prednimustine 100 mg/M2 orally once a day for four days. NSO was repeated every
21 days. Thirty-six patients were able to be evaluated. There were 18 males and
18 females with the median age of 71 (range 60-85). NSO was well tolerated and
nonhematological toxicities were uncommon. More than 80% of the patients received
90% or greater of the intended dose. The complete response rate was 60.6% and
partial response was 21.8%. At 60 months the Kaplan-Meier estimate of progression
free survival was 47.9% (standard error 8.6%) and actual survival was 40.6%
(standard error 8.8%). There were no differences in outcome between those with
performance status (PS) of zero or one and those with PS > 1. NSO is well
tolerated by elderly patients including those with PS > 1. These results compare
favorably with other combinations in elderly patients with aggressive non
Hodgkin's lymphoma.
PMID- 9766802
TI - Follicular dendritic cell sarcoma and interdigitating reticulum cell sarcoma: a
review.
AB - Neoplasms of reticular dendritic origin are extremely rare and include the
follicular dendritic cell sarcoma (FDCS) and the interdigitating reticulum (or
dendritic) cell sarcoma (IDCS). In this article, we review the literature
pertaining to the two diseases and describe clinical observations and salient
pathologic features, including information provided by authors of FDCS and IDDCS
reports. We performed a computerized database search for published articles
regarding FDCS and IDDCS. The articles were evaluated critically by the authors.
Simple descriptive statistics were used to analyze the data. There are 51 cases
of FDCS and 21 cases of IDDCS that are well documented in the literature. The
pathologic diagnosis of FDCS and IDDCS is often challenging and requires
morphologic, immunophenotypic, cytochemical, and electron-microscopic analysis.
Patients with FDCS usually present with cervical or axillary lymphadenopathy, but
extranodal disease has been described. In at least some patients, preexisting
Castleman's disease has been recognized. Resected localized disease may be
prevented from recurrence by consolidative radiotherapy. Chemotherapy regimens
have shown nondurable antitumor activity in FDCS. Patients with IDDCS usually
present with lymphadenopathy. The clinical course of IDDCS has been variable, but
it seems to be more aggressive than that of FDCS. Variable degrees of remission
may be achieved with chemotherapy. FDCS and IDDCS are rare neoplasms that may
pose difficulty in pathologic diagnosis. IDDCS seems to display a more aggressive
behavior than FDCS. Patients with IDDCS and FDCS can eventually die of disease
progression. The role of chemotherapy and radiotherapy is not clearly defined.
PMID- 9766803
TI - Significance of parathyroid hormone-related protein as a factor stimulating bone
resorption and causing hypercalcemia in myeloma.
AB - Elevated levels of parathyroid hormone-related protein (PTHrP) in hypercalcemic
myeloma patients were demonstrated in recent reports, suggesting that PTHrP
behaves as a humoral mediator of hypercalcemia in myeloma. Herein we describe a
hypercalcemic myeloma patient with a high serum PTHrP level. Moreover, the PTHrP
level in the supernatant of bone marrow aspirates was about two-fold of that in
serum. Reverve transcriptase-polymerase chain reaction analysis showed PTHrP m
RNA in bone marrow containing myeloma cells. After chemotherapy, the
concentrations of calcium and PTHrP decreased and PTHrP mRNA in bone marrow
became undetectable. We conclude that PTHrP released by myeloma cells acted as
the main bone resorption stimulating factor in this case.
PMID- 9766804
TI - Successful treatment of a patient with cardiac lymphoma who presented with a
complete atrioventricular block.
AB - A patient with primary cardiac lymphoma, which is very rare, generally is
regarded to have a poor prognosis. We herein report a patient with cardiac
lymphoma who was treated successfully by systemic chemotherapy and radiotherapy
using a pacemaker to control the complete atrioventricular (A-V) block. A 70-year
old man had a syncope caused by a complete A-V block. An echocardiogram, a
computed tomographic scan, and magnetic resonance imaging of his chest showed a
cardiac tumor. At this time, a biopsy of the cardiac tumor disclosed malignant
lymphoma (diffuse large cell type, B cell type). The patient was thus treated
with systemic chemotherapy and radiotherapy and, as a result, achieved a complete
remission with a disappearance of the A-V block. Recently, several successful
outcomes involving primary cardiac lymphoma have been reported because of the
progress in diagnostic techniques including echocardiography, computed
tomographic scanning, and magnetic resonance imaging, as well as improvement in
the therapy of malignant lymphoma. Our clinical experience indicated that an
early and accurate diagnosis combined with the appropriate therapy can thus help
in obtaining a long survival in patients with primary cardiac lymphoma.
PMID- 9766806
TI - Malignant lymphoma in association with multiple paraffin implants.
PMID- 9766805
TI - Familial idiopathic myelofibrosis and multiple hemangiomas.
AB - Idiopathic myelofibrosis (MF) is a rare disease in childhood. The clinical
spectrum is very variable. Familial idiopathic MF has been recorded
exceptionally. In previous reports idiopathic MF in childhood has been described
in association with congenital anomalies and with chromosome abnormalities,
although neither of these features have been reported in a familial context. We
report two sisters with idiopathic MF and multiple eruptive hemangiomas. Details
of their clinical signs, laboratory findings, and histologic features are
described.
PMID- 9766807
TI - Bone marrow mast cell disease associated with Felty's syndrome and liver
cirrhosis.
PMID- 9766808
TI - Prothrombin gene 20210 G-A mutation in Turkish patients with thrombosis.
PMID- 9766809
TI - Mechanism of activation of the GM-CSF, IL-3, and IL-5 family of receptors.
AB - The process of ligand binding leading to receptor activation is an ordered and
sequential one. High-affinity binding of GM-CSF, interleukin 3 (IL-3), and IL-5
to their receptors induces a number of key events at the cell surface and within
the cytoplasm that are necessary for receptor activation. These include receptor
oligomerization, activation of tyrosine kinase activity, phosphorylation of the
receptor, and the recruitment of SH2 (src-homology) and PTB (phosphotyrosine
binding) domain proteins to the receptor. Such a sequence of events represents a
recurrent theme among cytokine, growth factor, and hormone receptors; however, a
number of very recent and interesting findings have identified unique features in
this receptor system in terms of: A) how GM-CSF/IL-3/IL-5 bind, oligomerize, and
activate their cognate receptors; B) how multiple biological responses such as
proliferation, survival, and differentiation can be transduced from activated GM
CSF, IL-3, or IL-5 receptors, and C) how the presence of novel phosphotyrosine
independent signaling motifs within a specific cytoplasmic domain of betaC may be
important for mediating survival and differentiation by these cytokines. This
review does not attempt to be all-encompassing but rather to focus on the most
recent and significant discoveries that distinguish the GM-CSF/IL-3/IL-5 receptor
subfamily from other cytokine receptors.
PMID- 9766810
TI - The molecular control of hematopoiesis: progress and problems with gene
manipulation.
AB - The in vitro-based discovery and characterization of hematopoietic regulators
were of great value in identifying many of the agents active in controlling
hematopoiesis. Subsequent in vivo studies have validated most of the information
obtained from the in vitro studies, although the in vitro studies proved to be
somewhat misleading in predicting which agents would exhibit the greatest
quantitative effects in vivo. Establishing more clearly the actual situation in
vivo has required a return to more complex, and often less satisfactory, studies
on genetically manipulated whole animals. Of the two possible general approaches,
gene inactivation models have proved more informative than transgenic,
overexpression models. Each model has raised multiple questions in need of
further resolution and the deletion studies have also indicated that other
regulators must exist for various lineages, but have yet to be discovered. Of
particular interest is the finding from gene inactivation studies that both G-CSF
and thrombopoietin are necessary for the maintenance of normal numbers of
progenitor cells in multiple lineages, suggesting that each of these lineage
dominant regulators may have broader actions when operating on cells in the stem
cell and progenitor cell compartments.
PMID- 9766811
TI - Native thrombopoietin: structure and function.
AB - Thrombopoietin (TPO), the c-Mpl ligand, is produced constitutively in liver and
other organs, circulates in the bloodstream, and is delivered to bone marrow,
where it stimulates the early development of multiple hematopoietic lineages and
megakaryocytopoiesis. The concentration of TPO in blood is regulated by c-Mpl
mass on platelets and megakaryocytes. In addition to regulation by the number of
TPO molecules, including the possible modulation of TPO mRNA abundance in bone
marrow, megakaryocytopoiesis and platelet production may be regulated as a result
of modulation of TPO activity by proteolytic processing that generates truncated
forms of the molecule. Characterization of TPO partially purified from human
plasma, however, revealed that the full-length molecule was the predominant form
in the blood of both normal individuals and thrombocytopenic patients, although
small amounts of truncated species were detected. Thus, truncation of TPO, at
least that in the circulation examined, does not appear to contribute to the
direct regulation of platelet production in response to increased demand. Given
that native TPO isolated from the plasma of thrombocytopenic animals comprises
truncated forms, the truncation of TPO is likely of physiological importance in
the life history of this molecule.
PMID- 9766812
TI - Thrombopoietin in patients with hepatoblastoma.
AB - Marked thrombocytosis (over 50 x 10(4)/microl) is frequently seen in patients
with hepatoblastoma. Thrombopoietin (TPO), c-mpl ligand, has recently been
purified as the major physiological regulator of the thrombopoiesis and is mainly
produced in the liver. Since it is possible that TPO participates in
thrombocytosis and the tumor growth of this particular hepatic tumor, serum TPO
levels in addition to interleukin 1beta (IL-1beta) and IL-6 levels were assessed
in seven untreated patients by using a sandwich enzyme-linked immunosorbent
assay. High serum TPO levels were observed in all of the examined patients. The
level ranged from 3.15 to 11.02 (mean +/- standard deviation; 6.08+/-1.25)
fmol/ml. IL-6 levels were also somewhat higher than normal. Platelet counts,
however, appeared to correlate more with serum TPO levels (p = 0.1) than with IL
1beta (p = 0.5) and IL-6 (p = 0.2) levels. Furthermore, using the reverse
transcriptase polymerase chain reaction method, the expression of c-mpl mRNA was
found in five of eight hepatoblastoma tissues as well as TPO mRNA in all eight
tissues. These observations suggest that thrombocytosis in hepatoblastoma
patients results from the production of cytokine members, including TPO, within
tumor tissues. Additionally, it is possible that TPO might act as a type of
autocrine and/or paracrine system for cellular growth in this tumor.
PMID- 9766813
TI - Insulin-like growth factor-1 (IGF-1) has a costimulatory effect on proliferation
of committed progenitors derived from human umbilical cord CD34+ cells.
AB - The effects of insulin-like growth factor-1 (IGF-1) on highly enriched human
umbilical cord CD34+ cells were investigated in vitro. CD34+ cells were cultured
in serum-free medium containing stem cell factor (SCF), GM-CSF, and interleukin-3
(IL-3). Culture of CD34+ cells for one week in the presence of these cytokines
resulted in a dose-dependent increase in total cell number. Addition of G-CSF
together with SCF+IL-3+GM-CSF increased the proliferation of myelopoietic cells
as determined by the number of cells expressing the myelomonocytic marker CD64
and the granulocytic marker CD15 without significantly altering the number of
CD34+ cells in the cultures. In the presence of G-CSF, IGF-1 induced a dose
dependent increase in the total cell number and a moderate but significant
increase in the percentages of CD15+, CD64+ cells with sustained CD34+ cell
proliferation. We conclude that IGF-1 can enhance the in vitro proliferation of
committed progenitor cells derived from umbilical cord CD34+ cells.
PMID- 9766814
TI - Cell-surface antigen expression in early and term gestation fetal hematopoietic
progenitor cells.
AB - The objective of this study was to compare the expression of primitive cell
surface antigens on CD34+ cells from early in gestation to those from term
gestations. Fetal blood samples were obtained from 10 early gestation (21.0+/-0.8
[SE] weeks) and 12 term gestation (39.3+/-0.4 weeks) fetuses. The mononuclear
cell population was separated by red cell lysis. Two-color flow cytometry was
used to assess cell surface antigen coexpression of CD34 with CD33, CD38, and HLA
DR as well as staining by a cocktail of monoclonal antibodies for lineage
associated (Lin) antigens (CD2, CD10, CD11b, CD19, CD20, CD33, CD36, 7B9, and
Glycophorin-A). The frequency of CD34+ cells (5.5+/-0.9 versus 1.5+/-0.2, p <
0.001) was significantly higher in the early gestational age group. Within the
CD34+ population, the frequency of CD34+/CD38- cells (81.8+/-9.9 versus 51.3+/
7.7, p = 0.02) and CD34+/DR- cells (15.3+/-7.4 versus 8.2+/-2.7, p = 0.05) was
also higher in the early gestational age group. In contrast, CD34+/CD33- (51.8+/
10.1 versus 83.0+/-6.1, p = 0.02) and CD34+/Lin- cells (15.9+/-7.0 versus 51.8 +/
6.9, p < 0.01) were higher in the term gestation group. The high percentage of
CD34+, CD34+/CD38-, and CD34+/DR- cells supports our hypothesis that early
gestational age fetal blood has a higher frequency of primitive hematopoietic
progenitor/stem cells than does umbilical cord blood at term. This suggests that
hematopoietic progenitor/stem cells in early fetal blood may be a desirable
target for in utero gene therapy. However, further studies to characterize the
functional properties of CD34+ cell subsets at different stages of fetal
development will be necessary to determine the appropriateness of targeting fetal
hematopoietic cells for in utero gene therapy. The higher frequency of CD34+/CD33
and CD34+/Lin- cells from term gestational age fetuses was unexpected, and the
significance of this finding is unclear at this time.
PMID- 9766816
TI - Progenitor cell tumors in human liver.
PMID- 9766815
TI - Differential response of CD34+ cells isolated from cord blood and bone marrow to
MIP-1 alpha and the expression of MIP-1 alpha receptors on these immature cells.
AB - Macrophage inflammatory protein-1 alpha (MIP-1alpha) has been shown to have a
role in the control of myeloid stem and progenitor cell proliferation. Recent
evidence suggests that MIP-1alpha also has a stimulatory effect on proliferation
of mature progenitors as well as an inhibitory effect on immature progenitors in
vitro. We have compared the effect of MIP-1alpha on myeloid and erythroid colony
formation of CD34+ cells isolated from bone marrow and cord blood. In the
presence of MIP-1alpha, bone marrow granulocyte-macrophage-colony forming cells
(GM-CFC) were inhibited over a dose range of 15 ng/ml to 500 ng/ml, and GM-CFC
from cord blood CD34+ cells were stimulated over the same dose range. MIP-1alpha
suppressed BFU-E colonies in both bone marrow and cord blood. Using thymidine
suicide assays, the influence of MIP-1alpha on the cycling status of the cells
was assessed. A good correlation between the effect of MIP-1alpha on colony
formation and cell cycle progression was observed. These results suggest that
there is a differential response to MIP-1alpha when bone marrow and cord blood
CD34+ cells are compared. Using flow cytometry and a biotinylated human MIP
1alpha/avidin fluorescein conjugate, the expression of MIP-1alpha receptors on
CD34+ cells was assessed. The data indicated that there was little quantitative
difference in overall expression of receptors (82.9% versus 93%) from bone marrow
or cord blood, respectively. However, when Northern blot analysis was used, mRNA
for two different MIP-1alpha receptors CCR1 and CCR5 could be detected in bone
marrow, but only CCR1 mRNA was seen in cord blood CD34+ samples. Therefore, the
expression of different receptor subtypes on CD34+ cells may be responsible for
the difference in MIP-1alpha responsiveness observed.
PMID- 9766817
TI - Interaction between isolated and purified liver cells and small unilamellar
liposomes.
AB - AIMS/BACKGROUND: The mechanism of interaction and the role played by the vesicle
lipid composition for the selective association between liposomes and liver cells
were studied, at the ultrastructural level, by investigating both in situ and in
vitro the interaction between hepatocytes, Kupffer and endothelial liver cells
with egg-phosphatidylcholine (eggPC) or eggPC/stearylamine (9:1; mol:mol) reverse
phase evaporation (REV) liposomes. METHODS: Liver cells from rats, isolated by
enzymatic perfusion and purified by differential centrifugation, were incubated,
in a rotating bath at 37 degrees C, with liposomes (2.5 mM final liposomal lipid
concentration). Cell aliquots were withdrawn and processed for electron
microscope observation at fixed time intervals. Parallel experiments were carried
out by in situ liver perfusion with liposome suspensions. RESULTS AND
CONCLUSIONS: Our first conclusions are: 1) lipidic composition affects the rate
of liposomes uptake and internalization by hepatocytes; 2) liposome uptake by
hepatocytes or Kupffer cells is likely an endocytic process; 3) endothelial cells
internalize lipid vesicles as well; 4) liposome uptake was due to a phagocytic
activity for all isolated liver cells, while in the in situ observation
endothelial cells seem to use another mechanism (fusion); and 5) the rate of
internalization is related to the viability of the treated cells. Experimental
data seem to indicate that differential behaviour in the internalization of lipid
vesicles exists among parenchymal, Kupffer and endothelial liver cells. These
differences suggest that clearance of liposomes by these cells involves two
mechanisms (i.e., endocytosis or fusion) with different rates of uptake and
internalization that facilitate the design of carriers that can deliver drugs
preferentially to a specific liver cell type.
PMID- 9766819
TI - Short-term effects of transjugular intrahepatic portosystemic shunt (TIPS) on
functional liver plasma flow in patients with advanced cirrhosis.
AB - AIMS/BACKGROUND: TIPS, an effective procedure applied for the treatment of
complications of portal hypertension, is potentially followed by worsening of the
hyperdynamic circulation of cirrhosis and the impairment of liver function. The
aim of the present study was to evaluate short-term changes of functional liver
plasma flow after application of TIPS, using the hepatic (extrarenal) clearance
of D-sorbitol (S-HCl). METHODS: Twenty-five cirrhotic patients submitted to TIPS
for prevention of variceal rebleeding entered the study. At steady-state, during
constant infusion of a solution of D-sorbitol (25 mg/min), appropriate blood and
urine samples were collected in order to calculate S-HCI before and 120 min after
TIPS opening. In addition, the hepatic extraction ratio of D-sorbitol was
directly measured at the level of the right (Er), where TIPS was applied, and of
the left (El) hepatic veins; meanwhile the portocaval gradient (PCG) was
registered, before and after stent dilation. A comparison of values obtained
before and after TIPS application was performed by Student's t-test for paired
data. RESULTS: After application of TIPS, a substantial reduction was observed in
PCG (12.1+/-4.2 vs 24.8+/-4.3 mmHg; p<0.001) and Er values (20.6+/-14.8 vs 57.5+/
22.3 %; p<0.001) but not El values (47.4+/-22.0 vs 53.4+/-21.4 %; p=0.178). S-HCl
measured 120 min after TIPS opening was not statistically different from pre-TIPS
values (389.2+/-212.1 vs 394.6+/-152.7 ml/min; p=0.892), although S-HCl
variations in Child-Pugh class B patients were positively correlated with portal
pressure variations (r=0.63, p=0.016). CONCLUSION: Our results demonstrate that
in patients with advanced cirrhosis, TIPS procedure, while effective in reducing
portal hypertension, does not lead to alterations in the functional liver plasma
flow within the first 2 h.
PMID- 9766818
TI - Influence of transjugular intrahepatic portosystemic shunts (TIPS) on tissue
oxygenation in patients with cirrhosis.
AB - AIMS/BACKGROUNDS: The aim of this prospective study was to evaluate the influence
of transjugular portosystemic intrahepatic shunts (TIPS) on tissue oxygenation in
patients with cirrhosis and refractory ascites. METHODS: Five shunted patients
were included in the study. The blood and tissue oxygenation values were analyzed
12 days and 4 months after TIPS procedure. The results were compared with those
observed in patients treated by paracentesis. RESULTS: Unlike patients treated by
paracentesis, PaO2 values remained unchanged throughout follow-up in shunted
patients. After the TIPS procedure, there was a transient increase in systemic O2
transport and O2 uptake and a transient decrease in O2 saturation of hepatic
oxyhemoglobin. After 4 months, TIPS resulted in an increase in PCO2 values and
bicarbonate concentrations. CONCLUSIONS: The TIPS procedure seems to prevent the
decrease in PaO2 observed in patients treated by paracentesis and may improve the
respiratory alkalosis of cirrhosis.
PMID- 9766820
TI - Diaphragmatic and subcutaneous seeding of hepatocellular carcinoma following fine
needle aspiration biopsy.
AB - AIMS/BACKGROUND: We report the discovery of associated metastatic subcutaneous
and metastatic diaphragmatic nodules on the needle track after fine-needle biopsy
aspiration under echography, which has not yet been reported in the literature.
METHODS: A 35-year-old man with non-replicating hepatitis B virus presented with
a tumor that suggested hepatocarcinoma with cirrhosis. A diagnostic needle biopsy
was carried out before surgery. Twelve months later, he presented with a series
of four continuous metastatic diaphragmatic nodules on the inner wall lining the
needle track. Surgery was performed, followed by external radiation (40 Gy).
CONCLUSIONS: The risk of seeding following fine-needle biopsy aspiration of
hepatocellular carcinoma can no longer be considered negligable. The real risk is
probably underestimated. Even for biopsy of lesions localized to the inferior
part of the liver, diaphragmatic seeding is possible. This seeding necessitates
surgical resection, increasing the therapeutic morbidity of hepatocellular
carcinomas. We believe that in cases where investigation of a small hepatic tumor
suggests a hepatocellular carcinoma that could be resected, or for candidate
patients for liver transplantation. one should not puncture the tumor. If this
diagnostic biopsy is essential, then the needle track could be resected upon
surgery, after cutaneous external tattooing.
PMID- 9766821
TI - Hepatitis G virus infection in Spanish patients with hepatocellular carcinoma.
AB - AIMS/BACKGROUND: To establish the rate of infection with a newly discovered
Flaviviridae family member hepatitis G virus (HGV) -- in Spanish patients with
hepatocellular carcinoma (HCC), chronic alcoholic liver disease (CALD) with
cirrhosis, or hepatitis C virus (HCV)-induced chronic hepatitis (CH). METHODS:
The presence of HGV-RNA was assessed in sera of 117 patients divided in three
groups: group 1: 40 patients with HCC (35 men, mean age 62.7 years, SD 10.9
years); group 2: 41 patients with chronic alcoholic liver disease (CALD) (36 men,
mean age 52.5 years, SD 9.8 years); group 3: 36 patients with HCV-induced CH (27
men, mean age 35.8 years, SD 8.5 years). Serum samples were tested for HGV-RNA by
specific reverse transcriptase-polymerase chain reaction (RT-PCR). Serological
markers of hepatitis B virus (HBV) and HCV were investigated in all patients and
were negative in CALD patients, as a prerequisite for their inclusion in the
study. All patients in group 1 were also tested for HBV-DNA. RESULTS: Rates of
HGV-RNA positivity were, respectively, 47%, 10% and 28% in groups 1, 2 and 3.
Differences were significant between groups 1 and 2 (p=0.00017) and groups 2 and
3 (p= 0.042), but not between groups 1 and 3 (p=0.079). CONCLUSIONS: HGV
infection is common in HCC patients, but usually in association with HCV,
indicating that both agents share common routes of infection. HGV was the only
hepatitis virus detected in 12% of HCC patients, but its possible role in the
pathogenesis of HCC remains unclear.
PMID- 9766822
TI - Activated sub-populations of lymphocytes and natural killer cells in normal liver
and liver grafts before transplantation.
AB - AIMS/BACKGROUND: The anatomic structure of the liver suggests that it is a place
of intense trafficking between intra-hepatic and peripheral blood compartment
leukocytes. Furthermore, the liver contains a large number of passenger
leukocytes that may play a role in the appearance of donor-type microchimerism
after transplantation. In this study, we aimed to define the principal lymphocyte
sub-populations contained in donor peripheral blood and liver grafts and in
normal liver removed during minimally invasive surgery. METHODS: Liver biopsies
were taken at the time of vascular clampage during liver extraction from donors
in a brain dead state (GI: n=14). Normal liver biopsies were removed during
minimaly invasive surgery (GII: n= 10). RESULTS: We observed evidence of the
presence of lymphocytic activation associated with the two major CD8+ lymphocyte
and natural killer (NK) cell populations in the two groups, with a significant
increase in TCRgammadelta-bearing lymphocyte receptors between normal liver and
the liver graft. CONCLUSIONS: The presence of activated leukocytes in the graft
could have a fundamental role in induction of peripheral tolerance. This
activation could be the result of a basic immunological response linked to the
interaction of T cells and NK cells, and of secondary activation due to stress
and the conditions necessary for organ removal from donors in a brain dead state.
PMID- 9766824
TI - Replication error frequencies in primary hepatocellular carcinoma: a comparison
of solitary primary versus multiple primary cancers.
AB - AIMS/BACKGROUND: Replication errors (RERs) at microsatellite loci are associated
with the development of not only hereditary nonpolyposis colon cancer but also
sporadic cancers. To examine the association between RERs and human
hepatocarcinogenesis, we looked for microsatellite instability in solitary and
multiple primary hepatocellular carcinomas (HCCs). METHODS: DNAs were extracted
from 34 solitary primary HCCs and 14 HCCs with multiple primary cancers. Twelve
microsatellite alleles were amplified by PCR from the DNAs, and RERs were
assessed by their mobility shift. RESULTS: RERs were found in only two cases (6%)
of solitary HCC and four cases (29%) of HCC with multiple primary cancers. Two of
the four HCCs with multiple primary cancers showed RERs at two and three
microsatellite loci, respectively. Of 12 microsatellite loci examined, TP53 and
D16S476 sensitively detected RERs in HCCs with multiple primary cancers, at a
frequency of 23% and 33%, respectively. CONCLUSIONS: RERs are rarely associated
with carcinogenesis in human primary HCC, and RER-related genetic alterations may
be associated with a part of HCC with multiple primary cancers. If future studies
confirm this association, then the two probes TP53 and D16S476 may be useful for
the prediction of development of multiple primary cancers with HCC.
PMID- 9766823
TI - Hepatic metabolism of oxidatively modified apo E-free high-density lipoproteins.
AB - AIMS/BACKGROUND: The metabolism of rat apo E-free high-density lipoproteins (HDL)
was contrasted with oxidatively modified apo E-free high-density lipoproteins (OX
HDL) in the rat hepatoma cell, Fu5AH. RESULTS: When 10-100 microg/ml [125I]-HDL
or [125I]-OX-HDL were incubated with cells for 4 h at 37 degrees C, cellular
uptake of oxidized lipoproteins was twice control. In contrast, protein
degradation was equal. [125I]-HDL or [125I]-OX-HDL were incubated with the cells
for 4 h followed by a 4 h chase with unlabeled HDL and OX-HDL, respectively. In
these experiments, 80% of [125I]-HDL was resecreted from the cell within 30 min
while 50% of [125I]-OX-HDL was retained by the cell after 2 h. Electron
microscopy was used to determine if the OX-HDL was retained in lysosomes. Cells
were incubated with gold-labeled OX-HDL, and lysosomes were stained with acid
phosphatase. Gold-labeled OX-HDL was abundant in intracellular vesicles that were
not reactive to acid phosphatase. However, vesicles with a high content of OX-HDL
frequently stained positively for 3,3'-diaminobenzidine, a stain that reacts with
catalase and is used to detect peroxisomes. CONCLUSIONS: The present evidence
indicates that the cellular metabolism of OX-HDL is different from that of
unmodified HDL.
PMID- 9766825
TI - Cell-kinetic study of proliferating bile ductules in various hepatobiliary
diseases.
AB - AIMS AND METHODS: Proliferat bile ductules are classifiable histologically into
typical and atypical types. To clarify their histogenesis and regulation, we
examined their phenotype, proliferating and degrading characteristics, using
liver sections from 58 patients with various hepatobiliary diseases. RESULTS:
Typical ductules were found in all cases. Atypical ductules were also frequently
found in extrahepatic biliary obstruction (EBO), chronic hepatitis (CH), as well
as in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC).
Typical ductules completely expressed biliary-type cytokeratins, while atypical
ductules lacked complete biliary-type cytokeratins and often connected with
periportal hepatocytes. Proliferative indices of typical ductules in diseased
livers were higher than those in normal livers, while those of atypical ductules
were low in PBC and PSC and high in EBO and CH. Apoptosis was detected in typical
and atypical ductules. Perforin was preferably expressed on typical and atypical
ductules, compared with CD95. CONCLUSIONS: These findings suggest that typical
ductules reflect active proliferation of preexisting ductules. Atypical ductules
might be classifiable into two categories: those in PBC and PSC primarily reflect
ductular transformation (metaplasia) of periportal hepatocytes, while those in
EBO and CH reflect active proliferation and transformation of hepatocytes.
Apoptosis via perforin/granzyme B pathway may be involved in the maintenance of
homeostasis in ductular proliferation as degrading fraction.
PMID- 9766826
TI - Diagnosis of hepatopulmonary syndrome with contrast transthoracic
echocardiography and histological confirmation.
AB - We report a patient with cirrhosis and hepatopulmonary syndrome. This syndrome is
an entity characterized by anomalies in the arterial oxygenation in patients with
chronic hepatic disease and/or portal hypertension and demonstration of pulmonary
vasodilatation (PV) in absence of primary cardiac or pulmonary disease. We show
that the finding of PV with transthoracic contrast enhanced echocardiography
(TCEE) in the diagnosis of PV is real and corresponds to direct measurement of
capillary diameter by morphometry.
PMID- 9766827
TI - Primary liver tumour of intermediate (hepatocyte-bile duct cell) phenotype: a
progenitor cell tumour?
AB - A 57-year-old female patient presented with painless obstructive jaundice and
mild mesogastric pain; she was in good general condition on admission. Abdominal
ultrasonography revealed diffuse tumoral invasion of the liver, suggesting
diffuse metastases. A liver biopsy showed a tumour with a trabecular growth
pattern, composed of uniform relatively small cells, very suggestive of an
endocrine carcinoma. Additional immunohistochemical stains, however, did not show
any endocrine differentiation, but showed positivity for both hepatocyte-type
cytokeratins (cytokeratin 8 and 18) and bile duct-type cytokeratins (cytokeratin
7 and 19). In addition, parathyroid hormone-related peptide, shown to be a good
marker for cholangiocarcinoma, was immunoreactive. Electron microscopy revealed
tumour cells with an intermediate phenotype: the cells clearly showed hepatocyte
features on one hand and bile duct cell features on the other hand. Nine days
after admission, the patient died due to liver failure and hepatic
encephalopathy. Autopsy excluded another primary tumour site. Overall, this
tumour was a primary liver tumour with an intermediate phenotype and with a very
rapid clinical course. The intermediate (between hepatocyte and bile duct cell)
phenotype suggests an immature progenitor cell origin, which is concordant with a
rapid clinical course. This type of tumour has not been described previously and
provides additional evidence for the existence of progenitor cells in human
liver.
PMID- 9766828
TI - Paracetamol-induced liver toxicity after intravenous administration.
PMID- 9766829
TI - Transgenic studies of pain.
AB - A revolution in molecular biological technology has allowed, for the first time,
the study of pain at the level of the gene. The molecular genetic technique
currently garnering the most interest is the use of transgenic mice that either
overexpress, or do not express, presumably pain-related proteins. This paper
reviews the findings of investigations in which a transgenic mouse has been
assessed for nociceptive or analgesic sensitivity. As of this writing, 25
different kinds of mutant mice--lacking neurotrophins and their receptors,
peripheral mediators of nociception and hyperalgesia, opioids and their
receptors, non-opioid transmitter receptors, and intracellular molecules
participating in signal transduction--have been produced and tested on behavioral
assays of nociception. Results of these studies have been variously confirmatory,
contradictory and enlightening compared to conventional investigations. The
advantages and limitations of this approach to pain research are discussed.
PMID- 9766830
TI - Transient inhibition of responses to thermal stimuli of spinal sensory tract
neurons in monkeys during sensitization by intradermal capsaicin.
AB - A secondary zone of cutaneous hyperalgesia in humans is characterized by
increased pain to mechanical stimuli. In contrast, the perception of heat stimuli
delivered to a secondary zone of hyperalgesia in humans often shows a paradoxical
decrease in magnitude. A number of studies have shown that the responses of
spinal cord neurons to cutaneous mechanical stimuli after peripheral injury model
well the mechanical hyperalgesia. However, the responses of dorsal horn neurons
to thermal stimuli after peripheral injury have not been as carefully studied.
The present study examined the effects of intradermal capsaicin on the responses
of spinal sensory projection neurons to cutaneous mechanical and thermal stimuli.
Our observations indicate that the responses of identified sensory projection
neurons to heat are transiently reduced at the same time that responses of these
cells to mechanical stimuli are increased. These results confirm a role for
sensory projection cells in signaling the sensory discriminative aspects of pain
in humans and underscore the emerging complexity of dorsal horn circuitry and
sensory processing.
PMID- 9766831
TI - Memories of chronic pain and perceptions of relief.
AB - Clinicians and researchers often ask patients to remember their past pain. They
also use patient's reports of relief from pain as evidence of treatment efficacy,
assuming that relief represents the difference between pretreatment pain and
present pain. We have estimated the accuracy of remembering pain and described
the relationship between remembered pain, changes in pain levels and reports of
relief during treatment. During a 10-week randomized controlled clinical trial on
the effectiveness of oral appliances for the management of chronic myalgia of the
jaw muscles, subjects recalled their pretreatment pain and rated their present
pain and perceived relief. Multiple regression analysis and repeated measures
analyses of variance (ANOVA) were used for data analysis. Memory of the
pretreatment pain was inaccurate and the errors in recall got significantly worse
with the passage of time (P < 0.001). Accuracy of recall for pretreatment pain
depended on the level of pain before treatment (P < 0.001): subjects with low
pretreatment pain exaggerated its intensity afterwards, while it was
underestimated by those with the highest pretreatment pain. Memory of
pretreatment pain was also dependent on the level of pain at the moment of recall
(P < 0.001). Ratings of relief increased over time (P < 0.001), and were
dependent on both present and remembered pain (Ps < 0.001). However, true changes
in pain were not significantly related to relief scores (P = 0.41). Finally,
almost all patients reported relief, even those whose pain had increased. These
results suggest that reports of perceived relief do not necessarily reflect true
changes in pain.
PMID- 9766833
TI - Menstrual cycle modulation of tender points.
AB - Changes in pain sensitivity throughout the menstrual cycle were assessed in 36
normally menstruating women and 30 users of oral contraceptives. Pain sensitivity
was measured with palpation of rheumatological tender points and with pressure
dolorimetry. The number of tender points identified by palpation was greater in
the follicular (postmenstrual) phase of the cycle as compared to the luteal
(intermenstrual) phase in normally cycling women but not in users of oral
contraceptives. These findings are related to previously described physiological
and psychological features of the menstrual cycle, with particular emphasis on
the role of hormonal events in modulating pain perception, particularly in
musculoskeletal disorders such as fibromyalgia.
PMID- 9766832
TI - Sex differences in response to cutaneous anesthesia: a double blind randomized
study.
AB - The existing literature on experimentally induced pain indicates that there are
sex differences, with females displaying greater sensitivity. In epidemiological
studies, sex differences are also noted in the prevalence of a number of pain
syndromes, with females reporting more severe pain, more frequent pain, and pain
of longer duration. Complicating the interpretation of pain differences between
men and women in clinical samples are reports of sex differences in response to
pain-reducing medications. Studies in human subjects suggest that women respond
better to certain opioid analgesics than men following third molar extraction,
but few studies have assessed sex effects in effectiveness of topical
anesthetics. The purpose of this study was to test for sex differences in
response to a topical anesthetic, Lidocaine, using double blind, placebo
controlled experimental methodology, in combination with a magnitude matching
psychophysical protocol using a pressure algometer. The subjects were 21 female
and 23 male adult volunteers. Twenty-four subjects (12 males and 12 females) were
randomly assigned to the Lidocaine condition and 20 subjects were randomly
assigned to the placebo control condition (9 males and 11 females). The effect
size across sex for subjects in the Lidocaine treatment condition on the response
bias variable was large indicating the males rated the stimuli as less painful
than the females. Sex differences were not observed for discriminability in the
Lidocaine treatment condition. This study did not show sex differences in the
placebo condition. These results are particularly interesting in light of
previous work that has shown similar pain stimuli (pressure pain) to be the
stimulation most sensitive to sex differences. Results of this study suggest that
the protocol employed (pressure pain stimulus with magnitude matching task) is
sensitive to both anesthetic treatment and sex differences and represents an
improvement in pain assessment methodology for use in experimental studies and in
the clinic.
PMID- 9766834
TI - Sex differences in opioid and N-methyl-D-aspartate mediated non-opioid biting fly
exposure induced analgesia in deer mice.
AB - There is evidence for sex differences in responses to noxious stimuli and in the
expression and mediation of analgesia. In particular, results of investigations
with swim stress and the more ethologically appropriate stress of predator odor
exposure have suggested sex differences in N-methyl-D-aspartate (NMDA) receptor
system involvement in the mediation of analgesia. Whether or not this sex
difference generalizes to other environmental stressors is, however, not clear.
Biting flies are a natural aversive stimuli commonly encountered by wild and
domestic animals and humans. The present study examined the opioid and non-opioid
mediated nociceptive (50 degrees C hot plate) responses of reproductive male and
female deer mice, Peromyscus maniculatus, exposed to biting fly attack. A 30 min
exposure to biting flies (stable flies, Stomoxys calcitrans (L.)) elicited a
naloxone sensitive, opioid-mediated analgesia that was of a greater magnitude in
males than in female deer mice. In contrast, a 5 min exposure to biting flies
elicited a 'on-opioid' analgesia that was of similar magnitude in both sexes and
insensitive to both naloxone and the specific kappa opiate antagonist, nor
binaltorphimine. In male mice this non-opioid analgesia was antagonised by the
competitive NMDA antagonist, NPC 1262, while in reproductive females the biting
fly-induced analgesia was insensitive to NPC 12626. These results show that there
are sex differences in NMDA involvement in the mediation of the non-opioid
analgesia arising from brief exposure to the stress of biting fly attack. These
data from a common, natural environmental challenge support the presence of basic
sex difference in NMDA involvement in the mediation of stress-induced analgesia.
PMID- 9766835
TI - Wallerian degeneration and hyperalgesia after peripheral nerve injury are
glutathione-dependent.
AB - Experimental inflammatory compression injury to the sciatic nerve (chronic
constriction injury, CCI) induces Wallerian degeneration of axons and damages non
neuronal cells at the injury site in association with the development of
exaggerated pain-like behavior, or hyperalgesia, to noxious thermal stimuli in
the affected anatomical area. We examined whether glutathione, one of whose many
functions is an important endogenous antioxidant, influenced resulting
neuropathology and hyperalgesia following CCI. Dietary supplementation of the
amino acid N-acetyl-cysteine (NAC), a rate-limiting component of glutathione
production, beginning 1 day prior to CCI significantly diminished both Wallerian
degeneration, measured by quantitative morphometry of myelinated fibers, and
thermal hyperalgesia. NAC treatment raised nerve glutathione levels compared to
untreated nerves, as indicated using hemeoxygenase-1 (hsp32) immunoreactivity as
a marker of glutathione depletion. Because NAC is also known to have antioxidant
abilities, studies simultaneously inhibited glutathione synthesis, and results
demonstrated no significant reduction in resulting neuropathology or
hyperalgesia. Delaying NAC administration to post-injury times consistently
decreased hyperalgesia, although not significantly. This study identifies
glutathione levels, and presumably oxidative stress, as important determinants of
the neuropathological and behavioral consequences of nerve injury, and suggests
that dietary supplementation of NAC constitutes an effective pre-emptive
therapeutic strategy for situations involving painful nerve injury, such as
occurs during surgery.
PMID- 9766836
TI - Spinal bicuculline produces hypersensitivity of dorsal horn neurons: effects of
excitatory amino acid antagonists.
AB - In this study, we sought to characterize the effects of focal GABA(A) receptor
antagonism on spontaneous and evoked activity in dorsal horn neurons of the alpha
chloralose anesthetized cat. Bicuculline (0.5, 1.0 mM) applied near the neurons
through a transparenchymal dialysis fiber resulted in increased evoked activity
in nociceptive dorsal horn neurons. Hair deflection was the stimulus most
affected, followed by both low and high threshold tonic mechanical stimulation of
the receptive field. In addition, neurons displayed increased background
discharge and a subpopulation developed an increased afterdischarge to noxious
mechanical stimulation. This is in contrast to our previous work with glycine
receptor antagonism where only the evoked response to hair follicle activation
was significantly enhanced. Subsequent co-administration of an NMDA receptor
antagonist (AP-7, 2.0 mM) was without any apparent effect on either basal or
bicuculline-enhanced responses. Co-administration of a non-NMDA excitatory amino
acid receptor antagonist (CNQX, 1.0 mM) with the bicuculline non-selectively
blocked both low and high threshold mechanical input. The inability of AP-7 to
reverse the bicuculline-associated hyperreactivity also contrasts with the AP-7
reversal of the strychnine-associated hyperreactivity. These results point out
that, while GABA and glycine are frequently co-localized in cells of the spinal
dorsal horn and both appear to mediate tonic inhibitory control systems, they are
not at all equivalent and are subject to different modulatory pharmacologies.
Removal of each influence may model a different component of neuropathic pain.
PMID- 9766837
TI - Sensory changes in the territory of the lingual and inferior alveolar nerves
following lower third molar extraction.
AB - Post-injury inflammation activates nociceptive systems and recruits normally non
nociceptive afferents into a pain processing role. During inflammation, Abeta low
threshold mechanoreceptor afferents that usually mediate tactile sensation
acquire properties of nociceptors, allowing them to participate in post-injury
spontaneous pain and evoked abnormalities such as tenderness and pain to light
touch. This study assessed the sensory consequences of post-injury inflammation
following extraction of a single, lower third molar tooth. Extensive bilateral
evaluations were performed in the territory of nerves assumed to be exposed to
both inflammation and mechanical trauma, inflammation alone, or only the central
consequences of peripheral inflammation. Testing at the distal termination of
nerves assumed to be exposed to local inflammation (mental and lingual nerve
territory) revealed decreased detection thresholds (P < 0.05) to electrical
stimulation and to mechanical stimulation by sensitive, disposable filaments
developed and validated for this application. Testing at sites of assumed
inflammation and mechanical trauma (mental nerve territory) showed reduced pain
thresholds to electrical stimulation. Thermal detection and pain thresholds were
not altered at any location in patients, and no effects were observed in control
subjects receiving only local anesthetic injections. These results in humans are
consistent with recent experimental evidence that inflammatory processes alter
the central consequence of activity in large-diameter Abeta touch primary
afferents evoked under natural conditions by gentle mechanical stimulation. These
effects result in hyperesthesia, increased sensitivity to light touch, and
mechanical allodynia, pain evoked by normally innocuous stimulation of Abeta
primary afferents.
PMID- 9766838
TI - Predictive factors for 1-year outcome of low-back and neck pain in patients
treated in primary care: comparison between the treatment strategies chiropractic
and physiotherapy.
AB - The inability to predict outcome in patients with low back/neck pain leads to
inappropriate or unnecessary treatment. The aims of the study were to identify
prognostic factors for disability at 1-year follow-up in patients with back pain
visiting primary care, and to compare the effect of these in two treatment
strategies--chiropractic and physiotherapy. Data were taken from a randomised
trial on patients with back/neck pain visiting the general practitioner, in which
patients were allocated to chiropractic and physiotherapy as primary management.
Three hundred and twenty-three patients, aged 18-60 years, who had no
contraindications to manipulation and who had not been treated within the
previous month were included in the study. Multiple regression analysis was used
to identify prognostic factors. Dependent variables were mean Oswestry score and
mean change in Oswestry score at 12-month follow-up. The multiple regression
analysis revealed five significant (P < 0.001-0.01) prognostic factors; duration
of current episode, Oswestry score at entry, expectations of treatment, number of
localisations, and well-being. Besides, the regression coefficients for the
significant factors were compared between the two treatment strategies. No
significant difference in effect or regression coefficients for the prognostic
factors were seen between the two treatment strategies. Twelve per cent of the
patients had poor prognostic factors (duration > or = 1 month, more than one
localisation, low expectations of treatment and low well-being) at entry. These
patients had a mean Oswestry score above 20% at 1-year follow-up. Clinical
decision models for the management of patients with back pain visiting primary
care that consider prognostic factors need to be implemented and prospectively
evaluated.
PMID- 9766839
TI - Phantom sensations following acute pain.
AB - In human amputees with painful phantom sensations, mislocalizations of tactile
stimuli to the phantom increase with the amount of cortical representational
reorganization and the extent of phantom pain. A similar phenomenon was
incidentally encountered in healthy subjects. For reasons unrelated to the
question of mislocalization, we performed a study involving the application of
experimental acute pain to the hand followed by non-noxious tactile stimulation
of the ipsilateral lip. During lip stimulation, two out of six subjects
spontaneously reported perceiving an additional phantom-like sensation in the
hand synchronously to the non-noxious lip stimulation. Similar, although more
diffuse, phantom sensations were observed in two out of seven additional subjects
who were then tested specifically for this effect. The observation is compatible
with a pain-induced hyperresponsiveness of the cortical hand area to
somatotopically adjacent inputs from the lip. This suggests that, even in the
absence of deafferentation, pain can lead to a representational reorganization.
PMID- 9766840
TI - Chronic gynaecological pain: an exploration of medical attitudes.
AB - Women with chronic pelvic pain experience serious distress and lifestyle
disruption. Confronted with a difficult condition to diagnose and treat
effectively, doctors express a negative perception of this group of 'heartsink'
patients. This study aimed to characterise medical attitudes towards the
treatment of women with chronic pelvic pain. Tape recorded focus group
discussions with gynaecologists, general practitioners and patients were
transcribed and analysed using ethnographic software to identify themes. A postal
questionnaire was sent to 300 British gynaecologists of which 145 were returned
(48%). Principal components analysis identified five factors accounting for 32.4%
of the variance, labelled 'efficiency', 'complexity', 'socio-cultural
liberalism', 'pathology' and 'communication'. Scores for 'socio-cultural
liberalism' were higher among gynaecologists in the younger age groups, women,
and those giving their ethnic origin as Caucasian. Scores for 'pathology' were
lower among younger gynaecologists. A sex difference just failed to reach
statistical significance. Multiple linear regression confirmed significant
independent relationships with scores for 'socio-cultural liberalism' and
respondent sex, ethnicity and age group under 38 years.
PMID- 9766841
TI - Estrogens and the myth of male privilege.
PMID- 9766842
TI - Molecular and clinical aspects of neutrophil peroxidase deficiency:
multidisciplinary approaches on an international scale.
PMID- 9766843
TI - Insights into myeloperoxidase biosynthesis from its inherited deficiency.
AB - Myeloperoxidase (MPO) is a heme protein present in the granules of neutrophils
and monocytes. The activated neutrophil releases MPO into the phagolysosome or
into the extracellular space in response to a variety of agonists. During
concomitant activation of the NADPH-dependent oxidase, the stimulated neutrophil
also generates hydrogen peroxide, and in this way the MPO-hydrogen peroxide
halide system exerts its potent microbicidal activity. Recent interest in MPO has
extended well beyond the domain of innate host defense against infection and
includes generalized inflammatory diseases, atherosclerosis, and degenerative
neurologic diseases. Search of the various data banks using the cDNA sequence for
MPO has uncovered previously unsuspected relationships among peroxidatively
active proteins in widely different species. In addition, application of the
analytical tools of cell and molecular biology has allowed definition of specific
genotypes underlying MPO deficiency and the impact of particular mutations on the
fate of MPO precursors along the biosynthetic pathway. In parallel, such studies
have allowed significant advances in understanding of the normal steps in MPO
biosynthesis and intracellular targeting.
PMID- 9766844
TI - Prevalence of myeloperoxidase deficiency: population studies using Bayer
Technicon automated hematology.
AB - The Bayer-Technicon hematological devices differentiate leukocytes by their
peroxidase activity and their volume, displaying them as separate clusters.
Peroxidase deficiencies are manifested by the irregular location of these
clusters. This makes it possible to identify persons totally or partially lacking
myeloperoxidase. The deficiency is quantified by the myeloperoxidase index, which
is expressed for every routine analysis and for which normal values were
determined. Values of the myeloperoxidase index confirm varying degrees of
deficiency and prevalence. Family studies using these degrees show that the
hereditary pattern must be more complicated than the classical autosomal
recessive mode. A bigenic mode is suggested. While about half of the totally
deficient individuals detected were free of typical symptoms, in the other half
we found infectious complications that were sometimes life-threatening. The
hematological devices allow the identification of persons suffering from
eosinoperoxidase deficiency and from MPO deficiency of the monocytes. The latter
symptom seems to indicate immaturity of these cells and may lead to unexpected
diagnosis of malignancy.
PMID- 9766845
TI - Clinical manifestation of myeloperoxidase deficiency.
AB - Myeloperoxidase (MPO), an iron-containing heme protein localized in the
azurophilic granules of neutrophil granulocytes and in the lysosomes of
monocytes, is involved in the killing of several micro-organisms and foreign
cells, including bacteria, fungi, viruses, red cells, and malignant and
nonmalignant nucleated cells. Despite the primary role of the oxygen-dependent
MPO system in the destruction of certain phagocytosed microbes, subjects with
total or partial MPO deficiency generally do not have an increased frequency of
infections, probably because other MPO-independent mechanism(s) for microbicidal
activity compensate for the lack of MPO. Infectious diseases, especially with
species of Candida, have been observed predominantly in MPO-deficient patients
who also have diabetes mellitus, but the frequency of such cases is very low,
less than 5% of reported MPO-deficient subjects. Evidence from a number of
investigators indicates that individuals with total MPO deficiency show a high
incidence of malignant tumors. Since MPO-deficient PMNs exhibit in vitro a
depressed lytic action against malignant human cells, it can be speculated that
the neutrophil MPO system plays a central role in the tumor surveillance of the
host. However, any definitive conclusion on the association between MPO
deficiency and the occurrence of cancers needs to be confirmed in further
clinical studies. Clinical manifestations of this disorder depend on the nature
of the defect; an acquired abnormality associated with other hematological or
nonhematological diseases has been occasionally described, but the primary
deficiency is the form more commonly reported. Another area of interest pertinent
to MPO expression is related to the use of anti-MPO monoclonal antibodies for the
lineage assignment of acute leukemic cells, the definition of FAB MO acute
myeloid leukemia, the identification of biphenotypic acute leukemias, and their
distinction from acute leukemia with minimal phenotypic deviation. The advantage
of MPO monoclonal antibodies over the MPO cytochemical assay relies in the
ability of the former method to recognize the enzymatically inactive precursor
forms of MPO.
PMID- 9766847
TI - Molecular genetics of peroxidase deficiency.
AB - Myeloperoxidase (MPO) belongs to a family of related proteins which also includes
eosinophil, thyroid, and lactoperoxidase. The MPO gene is a 14-kb gene located on
the long arm of chromosome 17. Thus far four mutations (R569W, Y173C, M251T and a
14-base deletion in exon 9) have been identified in patients with MPO deficiency.
As in other genetically determined diseases, many more mutations will eventually
be revealed that cause this disease. Present evidence shows that most patients
are compound heterozygotes, i.e., they have inherited different mutations on
their paternal and maternal MPO alleles. Understanding why some patients with
this genetic deficiency develop clinical symptoms while others do not requires
mutation analyses of a large number of patients. This includes the analysis of
genotype-phenotype relationships. Genotyping has also been started in patients
with EPO-deficiency.
PMID- 9766846
TI - Autoantibodies to myeloperoxidase: clinical and pathophysiological significance.
AB - Autoantibodies to MPO are associated with various forms of systemic vasculitis,
including the renal limited form described as idiopathic crescentic
glomerulonephritis. In vitro the antibodies are able to further activate primed
neutrophils to the production of reactive oxygen species and the release of
lysosomal enzymes. In vivo experimental studies in which an autoimmune response
to MPO was induced in rats have demonstrated the in vivo potential of the
autoantibodies to aggravate subclinical inflammatory lesions. In the right
context, vasculitis and glomerulonephritis can ensue. Further studies are being
directed to the precise characterization of autoimmune responses in order to
obtain clues for the etiopathogenesis of the associated diseases.
PMID- 9766848
TI - The influence of antigenic variation on cytotoxic T lymphocyte responses in HIV-1
infection.
AB - The propensity of HIV-1 for genetic variation, a consequence of error-prone
reverse transcription combined with high rates of replication, is thought to
contribute to the establishment of persistent infection in the host despite the
presence of a vigorous antiviral immune response. Protective immunity to viruses
is mediated primarily by cytotoxic T lymphocytes, which recognize viral peptides
of 8-11 amino acids bound to major histocompatibility complex class I molecules
on the surface of infected cells. In this review we examine the mechanisms by
which mutation within peptide antigen-encoding regions of the viral genome
enables HIV-1 to evade recognition by virus-specific cytotoxic T lymphocytes. The
discussion is relevant to other genetically unstable viruses and more generally
to intracellular pathogens of variable antigenicity.
PMID- 9766849
TI - Estradiol enhances gene delivery to human breast tumor cells.
AB - The influence of estradiol on the delivery of plasmid DNA to estrogen receptor
positive MCF-7 human breast cancer cells was studied by the use of a reporter
assay and by histochemical staining. Continuous exposure to estradiol enhanced
the lipofectamine-mediated delivery of both pSV40-luciferase and pCMV beta
galactosidase in a concentration-dependent manner. Estradiol increased both the
amount of pCMV beta-galactosidase per cell and the total fraction of cells
competent to receive the transgene. The efficiency of transgene delivery to MCF-7
cells was further improved by repeating the transfection procedure in the
presence of estradiol. Although overall gene uptake was reduced in control cells
when studies were performed at room temperature (as opposed to 37 degrees C),
potentiation of gene uptake by estradiol was maintained. At a concentration of
100 microM, estradiol also enhanced delivery of the transgene to estrogen
receptor negative MDA-MB-231 breast tumor cells, indicating that the potentiating
effects of estradiol are not mediated through the estrogen receptor. These
studies are the first to raise the possibility that gene delivery to breast tumor
cells can be improved by estradiol in single- or repeated-treatment regimens.
PMID- 9766850
TI - Simultaneous occurrence of various mutations and polymorphisms in cis and in
trans of the galactose-1-phosphate uridyltransferase gene in a Turkish family
with classical galactosemia.
AB - Classical galactosemia, characterized clinically by acute hepatic dysfunction,
sepsis, cataract, and failure to thrive, is caused by deficiency of galactose-1
phosphate uridyltransferase (GALT). Galactose restriction normalizes these acute
symptoms; however, long-term complications such as intellectual deficits and
ovarian failure are conspicuous in the majority of patients. Here we report two
Turkish siblings with classical galactosemia. The clinical course of the two
children differed markedly: only the older girl suffered from severe acute
symptoms during the neonatal period, and she developed greater mental retardation
than her younger affected brother. The functional activity of GALT was virtually
absent in each affected children. The mother and two healthy siblings exhibited
approximately 50% normal GALT activity and the father approximately 25%.
Molecular analysis revealed that these two galactosemic siblings were homozygous
for a stop codon mutation of E340X in GALT exon 10. Moreover, two additional
mutations, a neutral polymorphism L218L and N314D, which are typical for the
Duarte-I variant, were found in the same GALT allele. The two healthy siblings
and the parents were heterozygous for these combinations of mutations. In
addition, the father's second GALT allele revealed three intron mutations at
nucleotide position 1105 (G-->C), 1323 (G-->A) and 1391 (G-->A) and the N314D
mutation, which correspond to the mutations of Duarte-2 variant. Our findings
indicate that in classical galactosemia several distinct mutations can be present
in one allele (in cis) of the GALT gene. Therefore it seems to be necessary to
examine all introns and exons of the GALT gene in galactosemic patients who do
not carry the Q188R mutation or another frequent mutation in the GALT gene.
PMID- 9766852
TI - Determination of the molecular species composition of diacylglycerols in human
adipose tissue by solid-phase extraction and gas chromatography on a polar phase.
AB - The free diacylglycerols (DAGs) in adipose tissue are involved in the metabolism
of stored lipids and hence are related to the supply of fatty acids for other
tissues. This paper describes a simple, fast, and reproducible method for the
identification and quantification of different molecular species of DAGs in human
adipose tissue. The method comprised solid-phase extraction on a diol-bonded
phase column combined with capillary GC analysis of silylated DAG derivatives on
a polar phase (65% phenylmethylsilicone). Separation of the DAGs was achieved
based on chain length, isomeric structure (1,2- and 1,3-DAGs), and degree of
unsaturation. The main DAGs were 1,2-OO, 1,2-OP, 1,2-LO and 1,2-LP. The
composition was corroborated by analysis of the component fatty acids of the
DAGs, 18:1(n-9), 16:0, and 18:2(n-6) being the three major fatty acids obtained.
PMID- 9766853
TI - Liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry
of omega- and (omega-1)-hydroxylated metabolites of elaidic and oleic acids in
human and rat liver microsomes.
AB - In order to characterize the nature of the active site of cytochrome P450 2E1,
the metabolism of various fatty acids with cis/trans geometric configurations has
been investigated. A system coupling atmospheric pressure chemical ionization
mass spectrometry detection with HPLC separation was developed as an alternative
method for the characterization of hydroxylated metabolites of oleic and elaidic
acids in rat and human liver microsomes. Oxidation of oleic and elaidic acids led
to the formation of two main metabolites which were identified by LC-MS and GC-MS
as omega and (omega-1)-hydroxylated (or 17-OH and 18-OH) fatty acids, on the
basis of their pseudo-molecular mass and their fragmentation. The assay was
accurate and reproducible, with a detection limit of 25 ng per injection, a
linear range from 25 to 1128 ng per injection, no recorded interference, intra
day and inter-day precision with variation coefficients <14%. This LC-MS method
was validated with oleic acid by using both radiometric and mass spectrometric
detections. A significant correlation was found between the two methods in human
(r=0.86 and 0.94 with P<0.05 and 0.01) and rat liver microsomes (r=0.90 and 0.85
with P<0.01 and 0.05) for 17-OH and 18-OH metabolites, respectively. HPLC coupled
to mass spectrometry for the analysis of hydroxylated metabolites of elaidic acid
offers considerable advantages since the method does not require use of a
radioactive molecule, completely separates the two hydroxymetabolites, confirms
the identification of each metabolite, and is as sensitive as the radiometric
analysis method. This method allowed the comparative study of oleic and elaidic
acid hydroxylations by both human and rat liver microsomal preparations.
PMID- 9766854
TI - Quantitation of individual molecular species of phosphatidylcholines by reversed
phase high-performance liquid chromatography with fluorometric detection.
AB - The multiplicity of phosphatidylcholines is caused by the presence of different
pairs of fatty acids in their individual molecular species and at least 27
miscellaneous fatty acids were identified in phosphatidylcholines in the serum of
healthy individuals by combined gas-liquid chromatography and mass spectrometry
in our present experiments. A method is described for the separation and
quantitation of molecular species of phosphatidylcholine in human serum. Total
phosphatidylcholine is isolated from lipids extracted from the serum with
chloroform-methanol (2:1) by reversed-phase liquid-liquid extraction and
subjected to reversed-phase high-performance liquid chromatography with a
discontinuous descending gradient of water. Separation is monitored by
fluorometry (340/460 nm) and absorption at 205 nm, if required. Up to 25
different molecular species of phosphatidylcholine may be quantified with a
satisfactory reproducibility (+/-5-8%). Data on the distribution of individual
molecular species in phosphatidylcholine of 53 normal serums are presented. The
method may be used for quantitation of these phospholipids also in other
biological materials (cell lines, leukemic cells from patients), and on a
micropreparative scale to isolate individual compounds. The speed of separation
as well as a satisfactory reproducibility are its principal advantages.
PMID- 9766851
TI - Enantioselective multidimensional gas chromatography-mass spectrometry in the
analysis of urinary organic acids.
AB - Enantioselective multidimensional gas chromatography-mass spectrometry is a
valuable tool for the enantioselective analysis of compounds from complex
matrices. Samples are separated initially on a precolumn and selected substances
then transferred on-line to a main-column coated with suitable chiral stationary
phase for enantioselective analysis with subsequent mass selective detection. In
this paper the method is used as an adjunct to urinary organic acid analysis to
provide information in patients with suspected inborn errors of metabolism.
Lactic acid, alpha-hydroxyisocaproic acid, 3-phenyllactic acid and 3-(4
hydroxyphenyl)-lactic acid are separated in a single run. In addition, the
enantioselective analysis of pyroglutamic acid is presented. D-Enantiomers of
amino acids and alpha-hydroxycarboxylic acids derived from amino acids, point to
a bacterial origin whereas the L-enantiomer is predominantly of endogenous
origin. Therefore the enantiomeric ratio of chiral metabolites is an important
parameter for the understanding of metabolic processes.
PMID- 9766855
TI - Studies on neurosteroids. VII. Determination of pregnenolone and its 3-stearate
in rat brains using high-performance liquid chromatography-atmospheric pressure
chemical ionization mass spectrometry.
AB - An assay method for pregnenolone and its 3-stearate in rat brains has been
developed using LC-atmospheric pressure chemical ionization (APCI) isotope
dilution MS. The extraction of the rat brain homogenate containing deuterated
internal standards (ISs) with organic solvent followed by silica gel mini-column
chromatography gave two fractions containing pregnenolone and its 3-stearate
together with the respective IS. Each fraction was derivatized into 3-acetate-20
methyloxime and 20-methyloxime, respectively, followed by silica gel mini-column
chromatography to remove the excess reagents, and then each derivatized fraction
was applied onto reversed-phase LC-APCI-MS. The method was applied to the
determination of these steroids in the gray matter and olfactory bulbs of rat
brains, which were divided into control and acute stressed specimens. Although
pregnenolone in both regions of the rat brains increased more than five times
after stress, its 3-stearate decreased after stress.
PMID- 9766856
TI - Efficient bispecific monoclonal antibody purification using gradient thiophilic
affinity chromatography.
AB - Bispecific monoclonal antibodies (bsMAbs), due their unique design, have a wide
range of potential applications in immunodiagnostics and immunotherapy. One of
the major limitations for the use of bsMAbs produced by hybrid-hybridomas is the
concomitant production of parental monospecific antibodies. The relative amount
of bsMAb secreted may vary between different hybrid-hybridomas. Hence, the
purification of the desired bispecific molecule from other forms is crucial.
Current purification methods include anion-exchange, HPLC on different matrices,
and dual affinity methods. Most of those methods include multiple steps and have
limitations on the purity or yield of the desired species. We report here a
simple single-step purification method, using inexpensive thiophilic
chromatography. This new method can potentially be scaled up, for industrial
proposes. Finally, based on the amino acid sequences and assembly of the two
heavy chains we attempt to explain the possible mechanism by which thiophilic
chromatography was able to resolve the bsMAbs from the monospecific species.
PMID- 9766857
TI - Drug accumulation in melanin: an affinity chromatographic study.
AB - The affinity of several drugs to melanin has been indirectly assessed using an
affinity chromatographic approach based on immobilized melanin. Plots of the
retention of the drugs on the affinity column versus the number of molecules
applied were fitted best by nonlinear, exponential curves characteristic for each
drug. These curves reflect the complexity of the binding behaviour, consisting of
a variety of hydrogen bonding, hydrophobic or ionic interactions as well as
cooperative or anti-cooperative interactions between the drug molecules and
melanin. The nonlinear fitting procedure was based on a descriptive function and
allowed to discriminate the binding behaviour according to parameter estimates
which specified the investigated drugs.
PMID- 9766858
TI - Detection of 4-hydroxycoumarin anticoagulants and their metabolites in urine as
part of a systematic toxicological analysis procedure for acidic drugs and
poisons by gas chromatography-mass spectrometry after extractive methylation.
AB - A gas chromatography-mass spectrometry (GC-MS) procedure was developed for the
detection of 4-hydroxycoumarin anticoagulants and their metabolites in urine as
part of a systematic toxicological analysis procedure for acidic drugs and
poisons after extractive methylation. The part of the phase-transfer catalyst
remaining in the organic phase was removed by solid-phase extraction on a diol
phase. The compounds were separated by capillary GC and identified by
computerized MS in the full scan mode. Using mass chromatography with the ions
m/z 291, 294, 295, 309, 313, 322, 324, 336, 343 and 354, the possible presence of
4-hydroxycoumarin anticoagulants and/or their metabolites could be indicated. The
identity of positive signals in such mass chromatograms was confirmed by
comparison of the peaks underlying full mass spectra with the reference spectra
recorded during this study. This method allowed the detection of therapeutic
concentrations of phenprocoumon and warfarin in human urine samples. In absence
of human urine, acenocoumarol, coumachlor, coumatetrayl, pyranocoumarin
(cyclocumarol) could be detected only in rat urine.
PMID- 9766859
TI - Report on the preparation of deuterium-labelled aconitine and mesaconitine and
their application to the analysis of these alkaloids from body fluids as internal
standard.
AB - Improved analysis of aconitine and mesaconitine, highly toxic compounds from
Aconitum species, in body fluids by gas chromatography-selected ion monitoring
with their deuterium-labelled analogues as internal standards (I.S.s) is
described. Deuterium-labelled analogues of aconitine and mesaconitine were
synthesized by the substitution of the N-alkyl group for a deuterium-labelled
one. The mass spectra of the derivatives of the deuterium labels closely
resembled that of the nonlabelled compounds except for an obvious mass shift
produced by substitution of the deuterium atoms at N-alkyl groups. Using these
deuterium-labelled compounds as I.S.s, the standard curves for aconitine and
mesaconitine were linear (r2=0.999 each) in the concentration range of 50 pg to
50 ng, respectively. The detection limit of the alkaloids was 10 pg each per
injection. The recovery, accuracy and precision of the analysis were evaluated
with three different concentration of spiked human blood and urine (n=5 each).
The recovery rates ranged from 97.6% to 101.3% and the standard deviations of the
interseries ranged from 2.1% to 3.9%. These I.S.s give us a more precise analysis
and may be useful in examining the behavior of these alkaloids in the human body.
PMID- 9766860
TI - Headspace solid-phase microextraction and gas chromatographic determination of
dinitroaniline herbicides in human blood, urine and environmental water.
AB - Solid-phase microextraction (SPME) is a unique extraction and sampling technique,
and it has been used for separation of volatile organics from water or other
simple matrices. In this study, we have used SPME to separate dinitroaniline
herbicides from complicated matrices of human urine and blood in order to broaden
its application to biomedical analysis. The SPME conditions were optimized for
water, urine and blood samples, in terms of pH, salt additives, extraction
temperature, and fiber exposure time. Urine or water (1.0 ml) spiked with
herbicides and 0.28 g of anhydrous sodium sulfate was preheated at 70 degrees C
for 10 min, and a polydimethylsiloxane-coated fiber for SPME was exposed to the
headspace at 70 degrees C for another 30 min; while spiked blood (0.5 ml) diluted
with water (0.5 ml) was treated at 90 degrees C in the same way. The herbicides
were extractable under these conditions, and could be determined by gas
chromatography-electron capture detector (GC-ECD). The recoveries of the
herbicides, measured at the concentrations of 0.50 and 1.0 ng/ml urine or water,
or 6.0 and 20 ng/0.5 ml blood, ranged from 35 to 64% for different herbicides
from water or urine, and from 3.2 to 7.2% from blood. The headspace SPME yielded
clean extracts of dinitroaniline herbicides from urine, blood or water, which
could be directly analyzed by GC-ECD without further purification. The peak areas
of the extracted herbicides were proportional to their concentrations in the
range 0.1-10 ng/ml in water or urine, or 1-60 ng/0.5 ml in blood. The lowest
detectable concentration of the herbicides lay in 0.1 ng/ml water or urine, or in
0.5 ng/0.5 ml blood. The intra- and inter-day coefficients of variation were
within 14% for most of the analytes. Although the recoveries of the herbicides
were rather low, the linearity of calibration curve and the precision were good.
The developed method is more sensitive and much simpler in sample preparation
than previously reported ones. With the established SPME method, a dosed
herbicide was successfully separated and determined in rats' blood.
PMID- 9766861
TI - Determination of Aconitum alkaloids in blood and urine samples. II. Capillary
liquid chromatographic-frit fast atom bombardment mass spectrometric analysis.
AB - Determination of fourteen alkaloids, toxic Aconitum alkaloids, aconitine,
mesaconitine, jesaconitine, hypaconitine and deoxyaconitine, and their hydrolysis
products, benzoylaconines and aconines, have been established using capillary
liquid chromatography (LC) fast atom bombardment mass spectrometry (FAB-MS) with
a frit interface. Protonated molecular ions were observed as base peaks in the
FAB-MS for these fourteen alkaloids. All the alkaloids were simultaneously
quantified with linear gradient LC elution by solvent mixture of acetonitrile and
0.3% trifluoroacetic acid using selected ion monitoring of the protonated
molecular ions. The calibration curves of these alkaloids were linear in
injection amounts ranging from 5 to 500 pg, and their detection limits were 1 pg
per injection (S/N=3). Solid-phase extraction using Sep-Pak Plus PS-1 was also
investigated to clean-up and concentrate alkaloids in blood and urine samples,
and showed satisfactory recoveries. This capillary LC-frit-FAB-MS method enables
determination of low levels of Aconitum alkaloids in blood and urine samples,
coupled with solid-phase extraction.
PMID- 9766862
TI - Three-step purification of lipopolysaccharide-free, polyhistidine-tagged
recombinant antigens of Mycobacterium tuberculosis.
AB - Previous work has shown that the study of host immune responses against
Mycobacterium tuberculosis, the causative agent of tuberculosis, requires the
availability of multiple mycobacterial antigens. Since purification of protein
from M. tuberculosis cells is extremely cumbersome, we developed a protocol for
purifying milligram amounts of ten recombinant antigens of M. tuberculosis from
E. coli cells. Purified proteins were immunologically active and free of
contaminants that confound interpretation of cell-based immunological assays. The
method utilizes a three-step purification protocol consisting of immobilized
metal-chelate affinity chromatography, size exclusion chromatography and anion
exchange chromatography. The first two chromatographic steps yielded recombinant
protein free of protein contaminants, while the third step (anion-exchange
chromatography) efficiently removed E. coli lipopolysaccharide, a potent
polyclonal activator of lymphoid cells. The recombinant proteins were
immunologically indistinguishable from their native (i.e., purified from M.
tuberculosis) counterparts. Thus the method provides a way to utilize recombinant
proteins for immunological analyses that require highly purified antigens.
PMID- 9766863
TI - Determination of morphine by high-performance liquid chromatography with
electrochemical detection: application to human and rabbit pharmacokinetic
studies.
AB - A rapid, sensitive, precise and accurate high-performance liquid chromatographic
assay with coulometric electrochemical detection was developed for the
determination of morphine in human, rabbit, pig and dog plasma. It includes a one
step extraction procedure with hexane-isoamyl alcohol (1:1, v/v) at pH 8.9
(adjusted with phosphoric acid) and reversed-phase liquid chromatography on a
microPorasil column. The mobile phase was composed of 5 mM sodium acetate buffer
(pH 3.75)-acetonitrile (25:75, v/v). A flow-rate of 1.2 ml/min at 20 degrees C
was used. The working potentials for the electrochemical detector were +0.20 V
for detector cell 1, +0.55 V for detector cell 2 and +0.75 V for the guard cell.
The limit of detection of morphine was 100 pg/ml of plasma. Repeatability,
precision and accuracy were also determined concomitantly. The calibration graphs
were linear in the concentration range 0.25-250 ng/ml with correlation
coefficients of 0.998+/-0.01 and with a minimum intercept of 0.05+/-0.08. The
precision in plasma was acceptable, with coefficients of variation less than 11%.
The absolute recoveries of morphine and nalbuphine (internal standard) were
between 86 and 89% and independent of morphine concentration. Pharmacokinetics
after oral morphine [MST Continus (morphine sulphate tablets) 30 mg, Bard
Pharmaceutical, Cambridge, UK] in humans revealed a one-compartment first-order
absorption model with one absorption phase and one elimination phase. The
absorption and elimination half-lives were 2.46 and 1.80 h, respectively.
Pharmacokinetics after intravenous morphine (3 mg/kg) in rabbits showed a linear
two-compartment open model with one distribution phase and one elimination phase.
The distribution and elimination half-lives were 0.5 and 33.8 h, respectively.
PMID- 9766864
TI - Role of stationary phase and eluent composition on the determination of log P
values of N-hydroxyethylamide of aryloxyalkylen and pyridine carboxylic acids by
reversed-phase high-performance liquid chromatography.
AB - The partition coefficients, P, between n-octanol and water of a number of growth
stimulating substances, N-hydroxyethylamide of aryloxyalkylen- and pyridine
carboxylic acids were obtained from Pomona College (C log P), and Rekker's (log
P(Rekker)) revised fragmental constant system was used to calculate log P data
sets. Both of these data sets were correlated with two different substance
lipophilicity parameters, log k(w) and phi0. Log k(w) was obtained by
extrapolation of log retention factor (k) to 0% organic modifier measured in
reversed-phase liquid chromatography (RPLC) systems. Phi0 values were obtained
from the slopes and intercepts of these relationships. The RPLC experiments were
performed on four commercially available reversed-phase columns. Binary mixtures
of methanol-water, methanol-phosphate buffer (pH 7.0), methanoltricine buffer (pH
7.0) and acetonitrile-water were used as mobile phases for the determination of
log k(w) values. For the methanolic eluents linear regression provided
satisfactory correlations (r>0.99) for the relationships log k vs. organic
modifier content in the eluent, while for the acetonitrile-containing eluents a
second-degree polynominal regression was necessary. For all four RPLC columns, by
linear regression satisfactory correlations (r>0.99) were obtained between log
k(w) and log P data using methanolic eluents. In such eluents phi0 values were
shown to be the second-best lipophilicity parameters. For acetonitrile-containing
eluents the use of second-degree polynominal regression was necessary and, in
contrast to methanol, significant influence of the applied column on regression
results was observed. For acetonitrile-containing eluents the phi0-index does not
provide satisfactory results for our substances. No difference in regression
results between the use of buffered and non-buffered eluents was observed.
PMID- 9766865
TI - Determination of medrogestone in plasma by high-performance liquid
chromatography.
AB - Interference with the UV absorbance of medrogestone by endogenous steroids in
plasma was prevented by reacting plasma with oxalyl chloride. The reduction of
interference was effective when oxalyl chloride was in the range 10-50 microl/ml
plasma. Reaction of oxalyl chloride with plasma for 10 min could reduce
interference approximately 5.5-fold, and there was no significant reduction after
30 min. The limit of quantitative concentration for medrogestone in HPLC was 1
ng/ml. The standard curves were linear with the correlation coefficient greater
than 0.999 in the range of 1-30 ng/ml. The coefficients of variation of both
intra- and inter-day mean values were <12% and <10% of the actual values,
respectively. The developed method for plasma sample preparation and the
evaluated HPLC condition were further applied to an in vivo pharmacokinetic
study.
PMID- 9766866
TI - Quantification of penicillin-G and procaine in equine urine and plasma using high
performance liquid chromatography.
AB - A rapid and sensitive method for the extraction and quantification of penicillin
G and procaine in horse urine and plasma samples has been successfully developed.
The method involves the use of solid-phase extraction (SPE) for penicillin-G,
liquid-liquid extraction (LLE) for procaine, and high-performance liquid
chromatography (HPLC) for the quantification of penicillin-G and procaine. The
new method described here has been successfully applied in the pharmacokinetic
studies of procaine, penicillin-G and procaine-penicillin-G administrations in
the horse.
PMID- 9766867
TI - Stereoselective binding of ketoprofen enantiomers to human serum albumin studied
by high-performance liquid affinity chromatography.
AB - A chiral stationary phase based on immobilized human serum albumin (HSA) was used
to study the stereoselective binding of ketoprofen enantiomers by means of high
performance liquid affinity chromatography. The technique of zonal elution was
applied together with a novel mathematical approach describing attachment to more
than one type of binding site. Phenylbutazon (PBZ) and diazepam (DAZ) were used
as markers for the major believed binding regions on HSA. Both R- and S
ketoprofen (KTR and KTS) display high affinity to the primary PBZ- and DAZ
binding sites and low-affinity to the secondary DAZ sites. The binding to high
affinity regions is accepted to be a stepwise process initiated by the binding to
the primary DAZ sites and followed by the attachment to the primary PBZ sites.
The chiral recognition is attributed to the high-affinity PBZ-binding sites and
to the low-affinity DAZ-binding sites.
PMID- 9766868
TI - Quantitative determination of the angiotensin-converting enzyme inhibitor
cilazapril and its active metabolite cilazaprilat in pharmaceuticals and urine by
high-performance liquid chromatography with amperometric detection.
AB - A rapid and simple high-performance liquid chromatographic method with
amperometric detection has been developed for the quantitation of cilazapril and
its active metabolite and degradation product cilazaprilat in urine and tablets.
The chromatographic system consisted of a microBondapak C18 column, using a
mixture of methanol-5 mM phosphoric acid (50:50, v/v) as mobile phase, which was
pumped at a flow-rate of 1.0 ml/min. The column was kept at a constant
temperature of (40+/-0.2) degrees C. Detection was performed using a glassy
carbon electrode at a potential of 1350 mV. Sample preparation for urine
consisted of a solid-phase extraction using C8 cartridges. This procedure allowed
recoveries greater than 85% for both compounds. The method proved to be accurate,
precise and sensitive enough to be applied to pharmacokinetic studies and it has
been applied to urine samples obtained from four hypertensive patients (detection
limit of 50 ng/ml for cilazapril and 40 ng/ml for cilazaprilat in urine). Results
were in good agreement with pharmacokinetic data.
PMID- 9766869
TI - High-performance liquid chromatographic determination of nemonapride and
desmethylnemonapride in human plasma using an electrochemical detection.
AB - A high-performance liquid chromatographic method using an electrochemical
detector (HPLC-ED) was developed for the determination of nemonapride and its
active metabolite, desmethylnemonapride in human plasma. Nemonapride,
desmethylnemonapride and moperone chloride, which was used as the internal
standard (I.S.) in plasma, were extracted by a rapid and simple procedure based
on C18 bonded-phase extraction, and were separated by C8 reversed-phase HPLC
column. Nemonapride and desmethylnemonapride were detected by high conversion
efficiency amperometric detection at +0.84 V. Determination of both nemonapride
and desmethylnemonapride were possible in the concentration range at 0.25-5.0
ng/ml, and the limit of detection for each was 0.1 ng/ml. The recoveries of
nemonapride and desmethylnemonapride added to plasma were 97.0-98.2% and 96.7
98.8%, respectively, with coefficients of variation of less than 7.2% and 10.3%,
respectively. This method is applicable to drug level monitoring in the plasma of
schizophrenia patients treated with nemonapride and to the study of
pharmacokinetics.
PMID- 9766871
TI - Determination of olanzapine in serum by high-performance liquid chromatography
using ultraviolet detection considering the easy oxidability of the compound and
the presence of other psychotropic drugs.
AB - A method for determination of the atypical neuroleptic drug olanzapine in serum
was developed. After a single-step liquid-liquid extraction, the compound was
separated from other constituents on a normal-phase silica gel column using a
buffer-methanol mobile phase and measured by UV absorption at 270 nm. Addition of
0.25% ascorbic acid to serum protects olanzapine against oxidation during
extraction and stabilizes the easily oxidised compound during storage. Inter-day
variation was <8% at serum levels found in olanzapine treated patients.
Analytical interference from coadministered psychoactive drugs and their
metabolites were studied. Only risperidone, also a relatively newly developed
antipsychotic drug, interfered, but the most commonly used antidepressants and
traditional antipsychotics and their metabolites did not interfere.
PMID- 9766870
TI - Determination of clozapine, desmethylclozapine and clozapine N-oxide in human
plasma by reversed-phase high-performance liquid chromatography with ultraviolet
detection.
AB - An isocratic high-performance liquid chromatography (HPLC) method with
ultraviolet detection for the simultaneous determination of clozapine and its two
major metabolites in human plasma is described. Analytes are concentrated from
alkaline plasma by liquid-liquid extraction with n-hexane-isoamyl alcohol (75:25,
v/v). The organic phase is back-extracted with 150 microl of 0.1 M dibasic
phosphate (pH 2.2 with 25% H3PO4). Triprolidine is used as internal standard. For
the chromatographic separation the mobile phase consisted of acetonitrile-0.06 M
phosphate buffer, pH 2.7 with 25% phosphoric acid (48:52, v/v). Analytes are
eluted at a flow-rate of 1.0 ml/min, separated on a 250 x 4.60 mm I.D. analytical
column packed with 5 microm C6 silica particles, and measured by UV absorbance
detection at 254 nm. The separation requires 7 min. Calibration curves for the
three analytes are linear within the clinical concentration range. Mean
recoveries were 92.7% for clozapine, 82.0% for desmethylclozapine and 70.4% for
clozapine N-oxide. C.V. values for intra- and inter-day variabilities were < or =
13.8% at concentrations between 50 and 1000 ng/ml. Accuracy, expressed as
percentage error, ranged from -19.8 to 2.8%. The method was specific and
sensitive with quantitation limits of 2 ng/ml for both clozapine and
desmethylclozapine and 5 ng/ml for clozapine N-oxide. Among various psychotropic
drugs and their metabolites, only 2-hydroxydesipramine caused significant
interference. The method is applicable to pharmacokinetic studies and therapeutic
drug monitoring.
PMID- 9766872
TI - Fully automated high-performance liquid chromatography of ciprofloxacin with
direct injection of plasma and Mueller-Hinton broth for
pharmacokinetic/pharmacodynamic studies.
AB - An isocratic high-performance liquid chromatographic method with column switching
and direct injection has been developed to determine ciprofloxacin in plasma and
Mueller-Hinton broth. An on-line dilution of the sample was performed with a
loading mobile phase consisting of 173 mM phosphoric acid. The analyte was
retained on a LiChrocart 4-4 precolumn filled with a LiChrospher 100 RP18, 5
microm. An electric-actuated system with two six-port valves allowed a clean-up
step with a mixture 20 mM phosphate buffer (pH 3.5)-methanol (97:3, v/v) and the
transfer of the analyte by a back-flush mode to a 150 x 4.6 mm I.D. column packed
with a Kromasil C8 5 microm, using a mobile phase of 20 mM phosphate buffer (pH
3.5)-acetonitrile (85:15, v/v). Fluorescence detection allowed a quantification
limit of 0.078 microg/ml with a 40-microl sample size. The method was evaluated
to determine its usefulness in studying the pharmacokinetic/pharmacodynamic
behaviour of ciprofloxacin in an in vitro model.
PMID- 9766873
TI - Characterization of a Helicobacter pylori vaccine candidate by proteome
techniques.
AB - In a previous two-dimensional (2D) gel electrophoretic study of protein antigens
of the gastric pathogen, Helicobacter pylori recognized by human sera, one of the
highly and consistently reactive antigens, a protein with Mr of approximately
30,000 (Spot 15) seemed to be of special interest because of low yields on N
terminal protein sequencing. This suggested possible N-terminal modification, as
the N-terminal sequence analysis of this 30,000 protein (Spot 15) did not provide
a definitive match within the H. pylori genomic database. This protein was
isolated by 2D polyacrylamide gel electrophoresis, evaluated by liquid
chromatography-mass spectrometry, and found to consist of two related species of
approximately 28,100 and 26,500. In parallel, the proteins within this spot were
digested in situ with the endoprotease Lys-C. Analysis of the Lys-C digest by
matrix-assisted laser desorption time-of-flight mass spectrometry, peptide
mapping, and sequence analysis was conducted. Comparison of the mass and sequence
of the Lys-C peptides with those derived from a H. pylori genomic library
identified an open reading frame of approximately 300 base pairs as the source of
the Spot 15 protein. This corresponded to HP0175 in the recently reported H.
pylori genome sequence, an open reading frame with some homology to Campylobacter
jejeuni cell binding protein 2. Mass spectral and sequence analysis indicated
that Spot 15 was a processed product generated by proteolytic cleavage at both
the carboxy and amino termini of the 34 open reading frame precursor.
PMID- 9766874
TI - Determination of 2-n-propylquinoline in mouse plasma and liver by high
performance liquid chromatography.
AB - A high-performance liquid chromatographic method was developed for the specific
determination of 2-n-propylquinoline, a new anti-leishmaniasis drug, in plasma
and liver homogenates of mice. 2-n-Propylquinoline was extracted with methyl
tert.-butyl ether with quinoline as internal standard. Separation was carried out
using a Nucleosil C18 column. The mobile phase consisted of methanol-0.005 M
ammonium acetate buffer (60:40) at pH 5.5 and 8 for plasma and liver homogenates,
respectively. Detection was monitored at 233 nm. The method was validated and
shown to be accurate and precise for plasma and liver homogenates. Extraction
yield was 96% in plasma and 81% in liver homogenates. This method was used to
determine the pharmacokinetic profile of 2-n-propylquinoline following oral
administration to mice.
PMID- 9766875
TI - Assay for the quinocarmycin analog DX-52-1 in human plasma using high-performance
liquid chromatography with automated column switching and low wavelength
ultraviolet detection.
AB - The hydrocyanated derivative of the antitumor antibiotic quinocarmycin, DX-52-1
(I), exhibits impressive activity against human melanoma xenograft models in
vivo. Phase I clinical trials to evaluate this compound as an antineoplastic
agent have been initiated by the US National Cancer Institute. We have developed
an HPLC assay for the determination of I in human plasma involving automated
column switching and UV detection at 210 nm. The preparation of samples for
chromatographic analysis entails the preliminary removal of plasma proteins by
precipitation with acetonitrile, acidifying the clear supernatant to pH 4.5, then
extracting twice with tert.-butyl methyl ether to recover the drug. A heart
cutting procedure employing two HPLC columns with contrasting retention
characteristics under isocratic reversed-phase conditions was used to achieve the
selectivity required for low wavelength UV detection of the analyte. The sample
extract was initially loaded onto a column packed with a cyanopropyl stationary
phase. During the predetermined time interval that I eluted from this column, a
fully automated six-position switching valve was used to direct the effluent onto
an octadecylsilane analytical column. The assay has been thoroughly validated
with regard to linearity, inter- and intra-day accuracy and precision, recovery,
selectivity and specificity. Using a sample volume of 1.0 ml, the lowest
concentration of I quantified with acceptable day-to-day reproducibility was
found to be 2.56 ng/ml (R.S.D. 18.9%, n=21, 4 months). This proved to be
sufficiently sensitive for pharmacokinetic drug level monitoring in cancer
patients treated with a 6-h continuous intravenous infusion of I, even at the
starting dose of 3 mg/m2. The successful performance and reliability of the assay
has been demonstrated through extensive application to the routine analysis of
plasma specimens acquired during a phase I clinical trial of the drug.
PMID- 9766876
TI - Trace analysis of SN-38 in human plasma by high-performance liquid
chromatography.
AB - A reversed-phase high-performance liquid chromatographic method with fluorescence
detection was developed and validated for the quantitation of SN-38, the active
metabolite of irinotecan (CPT-11), a new anticancer drug. This method uses solid
phase extraction with a C18 column for sample clean-up and concentration
following acidification of human plasma with two volumes of 0.1 M HCl. Using
blank plasma spiked with SN-38, we found the assay to be linear over the
concentration range of 10-500 pM (3.9-195 pg/ml) with acceptable total and within
day imprecision. The recovery of SN-38 ranged from 48.3% (10 pM) to 91.5% (500
pM) whereas that of the internal standard, 20-(S)-camptothecin, was 96.9% (500
pM). This method represents a sizeable increase in sensitivity over other
published methods and is shown to be suitable for the measurement of 'trough'
concentrations of SN-38 during the treatment of patients with a weekly regimen of
irinotecan.
PMID- 9766877
TI - High-throughput solid-phase extraction for the determination of cimetidine in
human plasma.
AB - For the implementation and validation of an automated 'high-throughput' solid
phase extraction (SPE) system, using microtiter solid-phase technology and a
pipetting robot, a SPE method previously validated manually for cimetidine in
human plasma was adapted. Sample cleanup was performed by means of SPE using
Microlute extraction plates in the 96-well format, each well filled with 50 mg of
Varian C18 sorbent. Separation was performed by reversed-phase high-performance
liquid chromatography (HPLC) with UV detection at 234 nm. The validated
calibration range was from 0.100 to 5.00 mg/l, with an inaccuracy and imprecision
below 20% at all concentration levels. Validation results on linearity,
specificity, precision, accuracy and stability are shown and are found to be
adequate. Cross-check analysis of samples from a clinical trial showed that there
is a good correlation between results obtained by the automated method and
results obtained by the manual method. The average sample preparation time for a
technician decreased from approximately 4 min per sample to 0.6 min. A sample
throughput of at least 160 samples per day can be achieved, the HPLC analysis
time being the rate-limiting step.
PMID- 9766878
TI - Determination of naringenin and its glucuronide conjugate in rat plasma and brain
tissue by high-performance liquid chromatography.
AB - An isocratic high-performance liquid chromatographic method with ultraviolet
detection was utilized for the investigation of the pharmacokinetics of
naringenin and its glucuronide conjugate in rat plasma and brain tissue. Plasma
and brain tissue were deproteinized by acetonitrile, then centrifuged for sample
clean-up. The drugs were separated by a reversed-phase C18 column with a mobile
phase consisting of acetonitrile-orthophosphoric acid solution (pH 2.5-2.8)
(36:64, v/v). The detection limits of naringenin in rat plasma and brain tissue
were 50 ng/ml and 0.4 microg/g, respectively. The glucuronide conjugate of
naringenin was evaluated by the deconjugated enzyme beta-glucuronidase. The
naringenin conjugation ratios in rat plasma and brain tissue were 0.86 and 0.22,
respectively, 10 min after naringenin (20 mg/kg, i.v.) administration. The mean
naringenin conjugation ratio in plasma was approximately four fold that in brain
tissue.
PMID- 9766879
TI - Liquid chromatographic determination of myocardial interstitial epinephrine.
AB - This study describes a high-performance liquid chromatographic method with
electrochemical detection (HPLC-ED) for monitoring of epinephrine (Epi) in the
myocardial interstitial space. The in vitro detection limit for Epi was 200 fg in
a 50-microl injection. Using a cardiac dialysis technique, 60-microl dialysates
were sampled from the myocardial interstitial space (6-min fractions). After an
alumina procedure, the dialysate Epi concentration was measured using the HPLC-ED
system. Although the basal Epi concentration was undetectable, local
administration of desipramine increased Epi concentration of the dialysate to
38.1+/-18.5 pg/ml. This system affords a new possibility for estimating
myocardial interstitial Epi level.
PMID- 9766880
TI - High-performance liquid chromatographic determination of a new oral thrombin
inhibitor in the blood of rats and dogs.
AB - A reliable reversed-phase high-performance liquid chromatographic method has been
developed for the determination of a new oral thrombin inhibitor (compound I) in
the blood of rats and dogs. The analyte was deproteinized with a 1.5 volume of
methanol and a 0.5 volume of 10% zinc sulfate, and the supernatant was injected
into a 5-microm Capcell Pak C18 column (150 x 4.6 mm I.D.). The mobile phase was
a mixture of acetonitrile and 0.2% triethylamine of pH 2.3 (31:69, v/v) with a
flow-rate of 1.0 ml/min at UV 231 nm. The retention time of compound I was
approximately 9.3 min. The calibration curve was linear over the concentration
range of 0.05-100 mg/l for rat blood (r2>0.9995, n=6) and dog blood (r2>0.9993,
n=6). The limit of quantitation was 0.05 mg/l for both bloods using a 100-microl
sample. For the 5 concentrations (0.05, 0.1, 1, 10, and 100 mg/l), the within-day
recovery (n=4) and precision (n=4) were 98.1-104.1% and 1.5-6.8% for rat blood
and 95.4-105.7% and 1.4-5.3% for dog blood, respectively. The between-day
recovery (n=6) and precision (n=6) were 99.8-105.3% and 3.7-12.6% for rat blood
and 87.5-107.1% and 2.9-15.3% for dog blood, respectively. The absolute
recoveries were 82.4-93.3%. No interferences from endogenous substances were
observed. In conclusion, the presented simple, sensitive, and reproducible HPLC
method proved and was used successfully for the determination of compound I in
the preclinical pharmacokinetics.
PMID- 9766881
TI - Simultaneous determination of ritonavir and saquinavir, two human
immunodeficiency virus protease inhibitors, in human serum by high-performance
liquid chromatography.
AB - The aim of this study was to describe an high-performance liquid chromatographic
assay for the simultaneous determination of two HIV protease inhibitors,
saquinavir and ritonavir, in human serum. The method involved extraction of
ritonavir and saquinavir from serum with the aid of solid-phase extraction C18
cartridges followed by high-performance liquid chromatography with a C8 column
and ultraviolet detection set at a wavelength of 240 nm. The assay was linear and
has been validated over the concentrations range of 0.5-32 microg/ml for
ritonavir and 0.075-4.8 microg/ml for saquinavir, from 600 microl serum
extracted. In future, the assay will be used to support human population
pharmacokinetic studies, and therapeutic drug monitoring for ritonavir and
saquinavir.
PMID- 9766882
TI - Sulfalene concentrations in plasma and blood cells of Plasmodium falciparum
malaria cases after treatment with metakelfin using high-performance liquid
chromatography.
AB - A reversed-phase high-performance liquid chromatographic method using
acetonitrile-methanol-1 M perchloric acid-water (25:9:0.8:95, v/v/v) at a flow
rate of 1.0 ml min(-1) on LiChrospher 100 RP 18 column (250 x 4 mm; 5 microm)
with UV (254 nm) detection has been developed for the determination of sulfalene
in plasma and blood cells after oral administration of the antimalarial drug
metakelfin. Calibration curves were linear in the range 0.5-100 microg ml(-1).
The limit of quantification was 50 ng ml(-1). Within-day and day-to-day
coefficients of variation averaged 3.84 and 5.31%, respectively. Mean extraction
recoveries of sulfalene from plasma and blood cells were 87.21 and 84.65%,
respectively. Mean concentrations of sulfalene in plasma of P. falciparum cases
on days 2, 7 and 15 were 44.58, 14.90 and 1.70 microg ml(-1), respectively; in
blood cells concentrations of sulfalene were 7.77, 3.25 and 0.75 microg ml(-1),
respectively, after oral treatment with two tablets (1000 mg) of metakelfin.
Significant difference was recorded on day 2 for sulfalene concentration in blood
cells of healthy and P. falciparum cases (t=9.49; P<0.001).
PMID- 9766883
TI - Determination of cisapride and norcisapride in human plasma using high
performance liquid chromatography with ultraviolet detection.
AB - A simple, rapid and reproducible high-performance liquid chromatographic assay
for cisapride and norcisapride in human plasma is described. Samples of plasma
(150 microl) were extracted using a C18 solid-phase cartridge. Regenerated tubes
were eluted with 1.0 ml of methanol, dried, redissolved in 150 microl of methanol
and injected. Chromatography was performed at room temperature by pumping
acetonitrile-methanol-0.015 M phosphate buffer pH 2.2-2.3 (680:194:126, v/v/v) at
0.8 ml/min through a C18 reversed-phase column. Cisapride, norcisapride and
internal standard were detected by absorbance at 276 nm and were eluted at 4.3,
5.3 and 8.1 min, respectively. Calibration plots in plasma were linear (r>0.998)
from 10 to 150 ng/ml. Intraday precisions for cisapride and norcisapride were
3.3% and 5.4%, respectively. Interday precisions for cisapride and norcisapride
were 9.6% and 9.0%, respectively. Drugs used which might be coadministered were
tested for interference.
PMID- 9766884
TI - Propagation and characterization of human herpesvirus-7 (HHV-7) isolates in a
continuous T-lymphoblastoid cell line (SupT1).
AB - After initial culture of HHV-7 in PHA-stimulated human cord blood mononuclear
cells (HCBMC), six HHV-7 isolates were propagated successfully in an immature
continuous T-lymphoblastoid cell line SupT1. All six isolates infected
efficiently the SupT1 cells, and the infected cells became grossly enlarged and
multinucleated 7-21 days post-infection. Various stages of HHV-7 morphogenesis
were detected. Cell-free supernatants from HHV-7-infected SupT1 cells were
infectious to HCBMC as well as to SupT1 cells. The HHV-7-infected SupT1 and HCBMC
cell lysates contained more infectious virus than the centrifuged cell culture
fluid supernates from the same culture. The HHV-7 isolates H7-2, H7-3, JHC, and
JB, concentrated 500 times, had average infectivity titers of 10(3.0) TCID50/ml
while strains H7-4 and KHR titered approximately 1-2 logs higher. When all six
HHV-7 isolates were propagated in SupT1 and culture fluid supernatants were
examined 14-21 days post-infection by negative stain electron microscopy they
contained an average of 1.9 x 10(9) virus particles/liter. IFA and ELISA, using
HHV-7/SupT1 cell lysate as an antigen, seem to correlate well in detecting high
and low HHV-7 antibody in sera from chronic fatigue patients and healthy donors
as controls. HHV-7 from SupT1 cell culture was free of HHV-6 and other human
herpesviruses as tested by PCR, and the HHV-7 PCR signal was still strong when
the viral preparation was diluted to 4.82 x 10(2) genome copies. Since HCBMC are
expensive to obtain and available in only small amounts, it is difficult to
obtain large quantities of HHV-7 antigen. On the other hand, the SupT1 cell is an
excellent source to produce consistently sufficient quantities of HHV-7 for
purification studies, development of immunodiagnostics, in vivo infectivity
studies, evaluation of antiviral drugs, and molecular biological studies.
PMID- 9766885
TI - Development of a dot blot neutralizing assay for HHV-6 and HHV-7 using specific
monoclonal antibodies.
AB - To elucidate further immune responses to human herpesviruses 6 and 7 (HHV-6 and
7), a neutralizing antibody assay was established for these viruses using a dot
blot method. Three monoclonal antibodies against HHV-6 and 12 monoclonal
antibodies against HHV-7 were developed and characterized by radio
immunoprecipitation. One monoclonal antibody which recognizes the 135 kDa late
polypeptide of HHV-6 and several which recognize the 125 kDa late polypeptide of
HHV-7 were selected to monitor virus growth by a dot blot antigen-detection
method. The dot blot method was then used for the assay of HHV-6 and -7
neutralizing antibodies in human serum samples. The neutralization endpoints
determined by the dot blot were comparable to those determined by
immunofluorescence (IF). The neutralizing antibody titers appeared to correlate
with the antibody titers determined by the indirect IF antibody test. The dot
blot neutralization assay is easy to perform, is highly reproducible and
objective when compared with the conventional methods based on cytopathology or
IF for determining neutralization endpoints.
PMID- 9766886
TI - Isolation of a retrovirus from multiple sclerosis patients in self-generated
Iodixanol gradients.
AB - The use of Iodixanol, a relatively new iodinated gradient medium, is described
for isolation of a retrovirus, which was harvested from the supernatant of
lymphoid cell lines originating from patients with multiple sclerosis (MS). The
virus is produced in low amounts and has been shown to be fragile, as manifested
in a loss of surface glycoproteins when purified in other gradient media. The
gradient fractions were analysed after centrifugation in Iodixanol by
incorporation of 3H-UTP, reverse transcriptase (RT) assays and electron
microscopy (EM) and it was found that Iodixanol does not cause the degree of
damage to the particles observed previously. These more favourable conditions are
probably due to low viscosity and almost iso-osmotic conditions even in high
concentrations. Furthermore, these advantages go together with higher
reproducibility in self-forming gradients, easier handling and shorter
centrifugation time. Iodixanol can also be used for preparation of HTLV-1.
PMID- 9766887
TI - Flow cytometric detection of EBV (EBER snRNA) using peptide nucleic acid probes.
AB - The application of peptide nucleic acid (PNA) probes for detection of Epstein
Barr Virus (EBV) snRNA in fixed cells is described. Fluorescein labelled PNA
probes were used to detect EBER1 and EBER2 snRNA in Raji, Daudi and HS-Sultan
cells. The fixation and permeabilization of cells were optimized. The optimal
fixation was found to be 5% acetic acid plus 4% paraformaldehyde in PBS and the
optimal permeabilization 0.5% Tween 20 in PBS whereas no proteolytic digestion
was needed. The hybridization time needed with the PNA probes was only 1 h. When
running mixed samples of Ramos (EBV neg.) Raji, Daudi and HS-Sultan (EBV pos.)
cells in flow cytometry a strong fluorescence signal was seen in Raji, Daudi and
HS-Sultan cells whereas no fluorescence signal was seen in the Ramos cells. In
total 0.5% EBER positive Raji cells could easily be identified in a mixture of
Raji and Ramos cells. The results were verified by fluorescence microscopy. It is
concluded that PNA probes can be used for in situ hybridization in solution and
the analysis can be done using flow cytometry or fluorescence microscopy. PNA
probes therefore may facilitate and enhance the potential use of the in situ
hybridization/flow cytometry combination.
PMID- 9766888
TI - Screening of horse polyclonal antibodies with a random peptide library displayed
on phage: identification of ligands used as antigens in an ELISA test to detect
the presence of antibodies to equine arteritis virus.
AB - A random hexapeptide fusion-phage library was screened to isolate phages that
bind to antibodies present in horse sera positive for equine arteritis virus
(EAV). Analysis of the peptide sequences displayed by isolated phages identified
seven groups. 25% of the isolated phages used as antigens in an ELISA test were
specifically recognised by a pool of sera which was positive for EAV in virus
neutralisation test (VN). Five of these, when used as antigen in ELISA, detected
greater than 50% of sera (n = 30) containing antibodies to EAV as detected by VN.
When these five phages were pooled together and used as antigen in ELISA, the
detection was improved. The sensitivity and specificity of the ELISA were 99 and
71%, respectively, compared with the EAV neutralisation test (n = 200). This
study has shown the potential that phage display libraries have for identifying
peptide sequences which could be used as antigen in diagnostic ELISAs.
PMID- 9766889
TI - A sensitive and specific ELISA immunocapture assay for rapid quantitation of
influenza A/H3N2 neuraminidase protein.
AB - Both HA and NA proteins elicit antibodies which have been shown to be capable of
altering the course of infection. Nevertheless, while influenza virus vaccine
standardization involves hemagglutinin (HA) and neuraminidase (NA) in terms of
antigenic characterization, only HA protein quantitation is undertaken. An
immunocapture ELISA (EIA) is described for N2 NA quantitation, based on the use
of a highly specific monoclonal antibody (MAb) for capturing NA and an anti-NA
antiserum for antigen detection. The amounts of NA in samples were deduced from
the standard curve established by using purified NA. The NA-EIA is specific and
detects as a little as 7 ng/ml. The capture and detector antibodies directed
against A/Beijing/32/92 NA were shown to react with H3N2 prototype strains used
in current influenza vaccines, provided that an antigenically matched reference
NA is used as standard.
PMID- 9766890
TI - Antigenic characterization of canine parvovirus strains isolated in Italy.
AB - 28 isolates of canine parvovirus type-2 (CPV-2) were obtained from dogs with
hemorrhagic gastroenteritis in Italy. The antigenic structure of CPV-2 isolates
was characterized, using four discriminating monoclonal antibodies. In addition,
four vaccinal strains were examined. Similar to reports from Australia and the
United Kingdom, a much higher prevalence of CPV-2a (25/28 isolates) was observed
than the other variant type, CPV-2b (3/28 isolates). DNA fragments (2.2 kbp) of
representative strains of CPV-2, CPV-2a and CPV-2b were amplified by the
polymerase chain reaction (PCR) and the products were digested by the restriction
enzymes (RE) RsaI, HpaII, HindIII and PvuII. The RvaI enzyme allows the
differentiation of CPV-2 from CPV-2a and CPV-2b.
PMID- 9766891
TI - A novel and innovative quantitative kinetic software for virological colorimetric
assays.
AB - This study addresses the limited range of quantification with colorimetric assays
(ELISA) starting from the analysis of color production in a reference external
curve. An automatic ELISA management software, designated Quanti-Kin Detection
System (QKDS) is described, which retains the sensitivity of the end-point
reading and extends the dynamic range up to five logarithms with mathematical
interpretation of color production. The QKDS software is a generic system
suitable for different types of ELISA with substrate incubation at room
temperature, does not require dedicated instruments, performs accurate
quantification (including assay quality control) and has a user friendly
interface. Specific applications were developed for three types of analytes:
antibodies, viral antigens and nucleic acids. Data are presented on three
representative QKDS applications to HIV antibodies, p24 antigen and proviral DNA
kits. The precision of quantification is strictly correlated with the precision
of the kit; however, for almost all samples with known analyte amount, the error
percentage was below 10%, only for two cases in quantification of HIV proviral
DNA the error percentage was around 25%. The necessity for a wide quantification
range has been demonstrated by measuring clinical samples, which showed a
distribution in all possible quantification ranges for all kits.
PMID- 9766892
TI - Hexon based PCRs combined with restriction enzyme analysis for rapid detection
and differentiation of fowl adenoviruses and egg drop syndrome virus.
AB - Three different polymerase chain reactions (PCRs), two of them combined with
restriction enzyme analysis (REA), were developed for detection and
differentiation of all 12 fowl adenovirus (FAV) serotypes and the egg drop
syndrome (EDS) virus. For primer construction FAV1, FAV10 and EDS virus hexon
proteins were aligned and conserved and variable regions were determined. Two
primer sets (H1/H2 and H3/H4) for single use were constructed which hybridize in
three conserved regions of hexon genes. Each primer pair amplifies approximately
half of the hexon gene including two loop regions. An amplification product was
detected with both primer sets using purified DNA from all FAV1-12 reference
strains. Viral EDS DNA was negative using the H1/H2 or H3/H4 primer pair. HaeII
digestion of the H1/H2 amplification products differentiates between all viruses
except FAV4 and FAV5. In comparison, much more clustering among genomic closely
related FAV serotypes was seen after HpaII digestion of the H3/H4 PCR products.
Oligonucleotides H5/H6 located in the variable regions of EDS virus hexon gene do
not detect any of the FAV serotypes. The PCRs and REA described are suitable to
detect all avian adenoviruses infecting chickens, to distinguish all 12 FAV
reference strains and to differentiate FAVs from the EDS virus.
PMID- 9766893
TI - Purification of Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) and
analyses of the structural proteins.
AB - The Kaposis's sarcoma-associated herpesvirus (KSHV) infected BCBL-1 cell line,
adapted to and grown in medium containing 10% horse serum, was induced to lytic
replication with 12-O-tetradecanoylphorbol-13-acetate (TPA) for virus production.
Supernatants from induced cells were filtered through a 0.45-microm filter and
virions were concentrated by polyethylene glycol extraction and high speed
centrifugation. The virus was purified by a glycerol gradient zonal
centrifugation step followed by isopycnic separation using positive density
negative viscosity gradients. Two visible bands were detected after the final
centrifugation step: an upper band that contained a homogenous population of
purified virions and a lower band that contained aggregates of purified virus and
other cellular debris. Fractionation of purified virion preparations by SDS-PAGE
revealed 32 bands with estimated molecular weights between 19 and 280 K in silver
stained gels. The glycoprotein bands in purified virus were identified with
biotinylated lectins and horseradish peroxidase-labeled streptavidin. Two lectins
were used to identify the KSHV glycoproteins: concanavalin A and Ricinus communis
agglutinin I. Eight distinct glycoproteins were detected with these lectins. In
addition, antisera from KS patients were used to detect immunoreactive proteins
in purified virions. An apparent immunodominant band of Mr 94,000 (94 K) was
recognized by patients' antisera. Other proteins detected with some of the KS
antisera tested corresponded to molecular weights of 57 K, 70 K, 180 K, 200 K and
240 K. The 94 K band was identified as gp94 by Endo F digestion.
PMID- 9766894
TI - Microplate-reverse hybridization method to determine dengue virus serotype.
AB - A reverse transcriptase-polymerase chain reaction (RT-PCR) and microplate-reverse
hybridization method were developed to detect and type dengue viruses in patients
plasma specimens. A silica method was used to isolate RNA; and 3'-noncoding
region universal primers were used to amplify dengue virus RNA. Using RT-PCR and
ethidium bromide staining we could detect dengue virus in serum spiked with
serially diluted dengue virus with a level of sensitivity similar to that of a
quantitative fluorescent focus assay of dengue viruses in cell culture, i.e. 1.4
fluorescent focus units per reaction. Applying this assay to 14 dengue-positive
plasma samples and 13 dengue-negative samples, dengue viremia was detectable by
RT-PCR with a sensitivity comparable to mosquito inoculation. To determine the
serotypes, digoxigenin-labeled PCR products from plasma samples and six
laboratory adapted dengue viruses were hybridized in stringent conditions to
serotype-specific DNA probes immobilized on microplates, and the hybridized
product was detected with a colorimetric assay. Serotypes of dengue viruses, in
cell culture and in patient plasma specimens, were identified using this method.
PMID- 9766896
TI - Determination of nuclear DNA concentration in cells of Myxobolus cerebralis and
triactinomyxon spores, the causative agent of whirling disease.
AB - Myxobolus cerebralis (Myxozoa: Myxosporea) has a complex two-host life cycle,
which begins when waterborne triactinomyxon spores released from the infected
oligochaete Tubifex tubifex contact a susceptible trout. Upon contact the
triactinomyxon spores attach to the fish and release their sporoplasm cells into
the epidermis. At approximately 50 days postinfection, sporogenesis begins,
resulting in a large number of M. cerebralis spores in the cartilage of infected
fish 6 weeks later. The spores of M. cerebralis can be released from infected
fish only after the fish die or are eaten by predators. In both cases, spores
released into the aquatic environment can be ingested by oligochaete worms of the
species T. tubifex and then develop into the actinosporean triactinomyxon stage
in the intestine within about 3 months. The triactinomyxon is the only stage
infectious for salmonid fish. We determined the DNA concentration in sporoplasm
cells, capsulogenic cells, and valvogenic cells of M. cerebralis spore stages
from the trout and of triactinomyxon spore stages from T. tubifex. DNA was
visualized using the DNA-specific fluorescent stain DAPI. Our results demonstrate
that meiosis occurs only once in the developmental cycle of M. cerebralis in
contrast to the previously published hypothesis. This takes place within the
pansporocyst found in T. tubifex. Thereafter, the sporoplasm cells of the
triactinomyxon spores in T. tubifex and M. cerebralis in trout are diploid.
PMID- 9766895
TI - Possible role of calmodulin in excystation of Giardia lamblia.
AB - The protozoan Giardia lamblia initiates infection when trophozoites emerge from a
cyst in the hosts by the excystation process. Although this process is crucial to
the initiation of infection by G. lamblia, little is known about its regulation.
To study the possible involvement of calmodulin (CaM) in excystation we tested
the effect of several CaM antagonists (TFP, W-7, and W-5) on this cellular
function. Except for W-5 the rest of these compounds inhibited excystation. The
protein kinase C inhibitor H-7 had no effect on excystation, suggesting that CaM
antagonists acted by selectively inhibiting CaM. Furthermore, CaM was
redistributed after the induction of excystation and there was an increase in its
fluorescence and activity. These results suggest that a CaM-dependent process is
involved in G. lamblia excystation.
PMID- 9766897
TI - Serodiagnosis of acute toxoplasmosis using a recombinant form of the dense
granule antigen GRA6 in an enzyme-linked immunosorbent assay.
AB - We developed an indirect enzyme-linked immunosorbent assay (ELISA) for the
serological diagnosis of acute toxoplasmosis that used the recombinant granule
antigen GRA6-GST as diagnostic antigen for the detection of IgG antibodies to
Toxoplasma gondii in human sera. A total of 431 sera obtained from 336 patients
with acute and chronic toxoplasmosis and from patients who were not infected with
T. gondii were tested. Sera from patients with acute T. gondii infection, chronic
infection, and no infection showed different absorbance values. For
discrimination between the presence and the absence of acute toxoplasmosis the
assay reached a specificity of 99.6%. Only one of the sera without significant
anti-T. gondii. IgM antibodies showed a positive reaction to rGRA6-GST. The assay
showed good intra- and interassay reproducibility (CV 6%/14%). We included a
glutathione S-transferase (GST)-IgG enzyme immunoassay as a control assay in this
study. Only 7 (4%) of 159 random sample sera reacted positively with GST.
PMID- 9766898
TI - Characterization of Giardia duodenalis by polymerase-chain-reaction
fingerprinting.
AB - The development of a polymerase chain reaction (PCR) based fingerprinting method
for the characterization of Giardia duodenalis isolates is described. The method
uses three different PCRs; one is specific for the A ("Polish") major group of G.
duodenalis isolates, another is specific for the B ("Belgian") group of isolates;
and one amplifies a fragment of the glutamate dehydrogenase gene present in all
G. duodenalis isolates. The PCRs perform highly sensitively on DNA from cultured
trophozoites. Isolates were further characterized by restriction-fragment-length
polymorphism (RFLP) analysis of the PCR products. In this way, representative
isolates from the A and B groups could be grouped together into a number of
subgroups. The stability of the genotypes with time and the reproducibility of
the two methods were tested on cloned and subcloned lines from a number of
isolates and proved to be highly satisfactory. The PCR/RFLP method was evaluated
on cysts derived from a number of human patients. It is concluded that the PCR
fingerprinting method described in this paper provides a reliable
characterization method for Giardia isolates and has the potential to be used as
a direct method of typing G. duodenalis cysts from feces.
PMID- 9766901
TI - Host choice by larval parasites: a study of Biomphalaria glabrata snails and
Schistosoma mansoni miracidia related to host size.
AB - Within snail/trematode associations the age/size of the host at infection has
consequences with regard to miracidial infection success, further intramolluscan
parasite development and reproduction, and the host response, mainly in terms of
growth and reproductive effort. Taking into account these differences, we were
interested in determining whether miracidia could discriminate and make a choice
between snails of different sizes. Using the Schistosoma mansoni/Biomphalaria
glabrata system, we compared data on the snail infection rate and the mother
sporocyst abundance among three size classes of snails (juvenile, subadult, and
adult) exposed separately or together to the parasite larvae. When exposed
individually, juvenile snails (3-5 mm) had significantly higher prevalence and
abundance values than did subadult snails, followed by adult snails. In contrast,
when snails of the three size classes were exposed together in heterogeneous size
groups the prevalence and abundance values were always significantly higher for
subadult snails of the 7- to 9-mm class than for juvenile and adult snails. A
host choice experiment confirmed that significantly more miracidia were attracted
by subadult snails, suggesting that the parasite has been selected for specific
locating and recognition mechanisms increasing the infection rate of subadult
snails when the latter have been exposed in a heterogeneous size group. Selective
forces that may be responsible for such a preferential infectivity of the
parasite vis-a-vis particular host age/size class are discussed in relation to
host resources and host responses.
PMID- 9766899
TI - The level of the collagen cross-link pyridinoline reflects the improvement of
cutaneous lesions in one case of skin alveolar echinococcosis.
AB - Cutaneous parasitic lesions, associated with a dense fibrous reaction, markedly
improved under albendazole treatment in one case of supraumbilical skin
localization of alveolar echinococcosis. Since collagen cross-linking increases
during fibrogenesis and contributes to the stability of fibrotic lesions, we
monitored the level of the cross-links pyridinoline and pentosidine in skin
lesions from this patient to determine if they would reflect the changes
occurring during treatment. We looked at the deposition of cross-linked type I
collagen by immunohistochemistry and also measured the serum concentrations of
pentosidine and of a fragment of type I collagen (ICTP), which contains a site of
pyridinoline formation. Albendazole treatment did not affect either the collagen
content of skin lesions or the serum concentrations of ICTP and pentosidine, but
it led to a pronounced decrease in pyridinoline level concomitant with the
disappearance, observed by immunohistochemistry, of extensively cross-linked
fibrotic type I collagen. The follow-up of collagen cross-linking by pyridinoline
in skin tissue thus appears to be useful in reflecting the improvement of
fibrotic skin diseases during therapy.
PMID- 9766900
TI - Effect of glucantime on field and patient isolates of New World Leishmania: use
of growth parameters of promastigotes to assess antimony susceptibility.
AB - The effect of pentavalent meglumine antimoniate (glucantime) on the growth
kinetics of promastigotes of 13 South American Leishmania strains isolated from
patients, sylvatic reservoirs, and vectors was studied. Four of five L. (Viannia)
braziliensis human isolates were obtained from drug-responsive patients and one
was isolated from an unresponsive mucocutaneous-type infection. Studies involved
the cell yield at the late log phase, the growth rate, and the growth-curve
patterns of promastigotes in vitro. Restriction-fragment-length polymorphism,
pulsed-field gel electrophoresis, and hybridization with the gene coding for a P
glycoprotein from L. (V.) guyanensis were used in an attempt to correlate the
resistance phenotype with gene amplification. Consistent differences observed in
both cell yield and growth rate among the isolates in the presence of glucantime
indicated these parameters to be good criteria for the estimation of
susceptibility to glucantime. Drug susceptibility varied widely between strains,
indicating a great genetic heterogeneity of the isolates. Five L. (V.)
braziliensis strains and three L. (V.) guyanensis strains were shown to be
susceptible to glucantime. Five isolates were resistant, four of which were
obtained from sylvatic vectors and one, from a patient with an unresponsive
mucocutaneous infection. Molecular analyses of total DNA indicated the presence
of a pgpA-related gene in all strains tested. No amplified sequence could be
detected, suggesting that pgpA amplification is not involved in glucantime
resistance in these wild Leishmania strains.
PMID- 9766902
TI - Immunohistochemical characterization of a polyclonal antibody against
Sphaerospora dicentrarchi (Myxosporea: Bivalvulida), a parasite from sea bass
(Dicentrarchus labrax L.) (Teleostei: Serranidae).
AB - Rabbit antibody was raised against Sphaerospora dicentrarchi, a histozoic
parasite of sea bass (Dicentrarchus labrax L.). Light and electron
immunohistological staining were used to characterize its specificity and
possible reactivity toward other fish parasites. In light immunohistochemistry
the polar capsules and valves of the S. dicentrarchi spores appeared strongly
stained, whereas developmental stages were not. Electron microscopic
histochemistry revealed intense labeling in valves and some developmental stages.
Cross-reaction was observed with all the myxosporean parasites assayed, even with
those belonging to other genera. Polar capsules of all the myxosporean species
except Polysporoplasma sparis were the main structures stained by the polyclonal
antibody. These observations could reveal the existence of conserved antigenic
epitopes in polar capsules of different Myxosporea.
PMID- 9766903
TI - Multiple bacteroids in the bacteriome of the lantern bug Pyrops candelaria Linn.
(Homoptera: Fulgoridae).
AB - Bacteriome in the lantern bug Pyrops candelaria harbored a-, t-, and companion
bacteroids. The a- and t-bacteroids were irregular bodies, whereas the companion
bacteroids were rod-shaped and easily distinguished from the others. The a- and t
bacteroids were enveloped by three membranes and the companion bacteroids, by two
membranes. The cytoplasm of the a-bacteroid contained electron-dense bodies.
PMID- 9766904
TI - Amebicidal activity of plant extracts from Southeast Asia on Acanthamoeba spp.
AB - The effect of 100 polar and 100 nonpolar plant extract materials obtained from
Southeast Asia were evaluated for amebicidal activity in vitro against three
species of Acanthamoeba. A. culbertsoni, A. castellanii, and A. polyphaga, the
causative agents of granulomatous amebic encephalitis and amebic keratitis, were
studied in vitro to determine whether the plant extracts exhibited amebicidal
activity or induced encystment of the amebae. Of the 200 plant extracts tested,
extracts obtained from three plants (Ipomoea sp., Kaempferia galanga, and Cananga
odorata) were amebicidal for all three species of Acanthamoeba and a fourth
extract prepared from Gastrochilus panduratum was lytic for A. polyphaga and
growth-inhibitory for A. castellanii and A. culbertsoni. Three plant extracts
induced encystment of all three species of Acanthamoeba. Select plant extracts
were tested as well for tumoricidal activity against B103 neuroblastoma cells.
Some plant extracts that exhibited tumoricidal activity for B103 cells were not
amebicidal for Acanthamoeba spp. Additionally, the polar and nonpolar extracts
that exhibited amebicidal activity were also tested for activity against primary
murine peritoneal macrophage cultures. Plant extracts that demonstrated
tumoricidal or amebicidal activity were not lytic for normal macrophage cultures.
PMID- 9766905
TI - Longer-term population dynamics of Gyrodactylus bullatarudis and G. turnbulli
(Monogenea) on adult guppies (Poecilia reticulata) in 50-I experimental arenas.
AB - Two suprapopulations of monogeneans, one each of Gyrodactylus bullatarudis and G.
turnbulli, on two groups of ten experimentally infected adult guppies (Poecilia
reticulata) were maintained separately in 50.1 aquaria and monitored over 210
days. The G. bullatarudis population had a pattern of initial growth, then a
subsequent decline to extinction after 40 days. G. turnbulli, after initial
population growth and decline, maintained low-intensity infections (0.33-3.3
parasites/host) on six hosts over 94 days and did not become extinct during the
experiment. There were some differences between the host-site specificity of G.
bullatarudis and G. turnbulli on adult P. reticulata as compared with previously
observed infections on immature fish.
PMID- 9766906
TI - Characterization of levamisole binding sites in Trichinella spiralis.
AB - Characterization of the levamisole receptor was performed with total extracts of
Trichinella spiralis muscle larvae using binding assays with tritiated levamisole
([3H]LEV, 291 GBq/mmol). We detected a specific [3H]LEV binding activity with a
dissociation constant (Kd) of 4.76 microM and a receptor density (Bmax) of 2.14
pmol/mg of protein. In inhibition studies, only dimethylphenylpiperazinium iodide
(DMPP) and hexamethonium were found to be competitive inhibitors of the [3H]LEV
binding with an inhibition constant (Ki) of 31.04 and 4.43 microM, respectively,
whereas d-tubocurarine and alpha-bungarotoxine had no effect on [3H]LEV binding
activity, and procaine and atropine potentiated the [3H]LEV-receptor binding. All
these data support the idea that levamisole acts as a cholinergic agonist in T.
spiralis.
PMID- 9766907
TI - Biochemical characterization of the Golgi-complex proteins of Tritrichomonas
foetus.
AB - Using cell-fractionation techniques (differential and discontinuous gradient
centrifugation), we obtained a highly enriched fraction containing the Golgi
complex of Tritrichomonas foetus. This fraction was further subfractionated by
sodium carbonate (150 mM) treatment at pH 11.5, leading to the isolation of the
Golgi content and membrane subfractions. Both fractions were characterized by
electron microscopy. The protein content of membrane and luminal subfractions was
about 40% and 60% of the total Golgi protein, respectively. Sodium dodecyl
sulfate-polyacrylamide gel electrophoresis analysis showed an enrichment of 15
protein bands in the Golgi fraction, with molecular masses varying between 15 and
116 kDa. Alkaline treatment released some proteins into the medium, but most of
them were associated with the Golgi membrane.
PMID- 9766908
TI - A recombinant protein disulfide isomerase homologue from Ancylostoma caninum.
AB - The objective of this study was to characterize a recombinant antigen of
Ancylostoma caninum that had been identified by immunoscreening with selected
antisera as described elsewhere. In vitro expression of clone Ac38-1 produced a
protein with an apparent molecular mass of approximately 38 kDa, which reacted in
Western blots with the antiserum from rabbits experimentally infected with L3 and
also with affinity-purified antibodies against hydrophilic proteins of the
cephalic glands obtained from the antiserum against the intestine, cephalic
glands, and cervical glands of adult worms. It was recognized not by antisera
from dogs percutaneously infected with 1,000 L3 of A. caninum but by antiserum
from dogs infected with 100,000 L3 of A. caninum. DNA sequencing of clone Ac38-1
showed a cDNA fragment with a coding region of 1,014 bp. Comparison of clone Ac38
1 with the Genbank DNA data base revealed 78% identity with a 244-bp segment of
the cm5b5 clone of the free-living nematode Caenorhabditis elegans coding for a
protein disulfide isomerase gene. The deduced amino acid sequence of clone Ac38-1
showed 82% identity with a 334-amino-acid (aa) segment of the protein disulfide
isomerase of C. elegans and 73% identity with a 334-aa segment of the protein
disulfide isomerase aa sequence of Onchocerca volvulus.
PMID- 9766909
TI - Occupational health in Australia.
AB - Australia is a developed country in the Asia-Pacific Region with a large land
area but a small population. Its main economic activities are mining, agriculture
and manufacturing, with its service and high-technology industries being the
fastest growing sectors in recent years. The regulation and enforcement of
Occupational Health and Safety policies are mainly administered by the Industrial
Relations Departments of eight State and Territory jurisdictions in the country.
A National Occupational Health and Safety Commission coordinates occupational
health and safety at the Commonwealth level. In 1987 the six occupational health
and safety priorities in Australia were listed as occupational back pain,
management of chemicals used at work, occupational noise-induced hearing loss,
occupational skin disorders, occupational cancer and mechanical equipment injury.
Australia has probably the highest incidence of malignant mesothelioma in the
world, although the use of asbestos has been largely phased out. There was an
almost explosive "epidemic" of repetition strain injury in the 1980s.
Approximately 500 work-related fatalities and 10,000 work-related injuries are
notified for workers' compensation every year. In addition, it is estimated that
there are several thousand cases of work-related diseases every year, many of
which go unreported. Occupational physicians undergo 4 years of specialisation
training. Occupational hygienists, nurses and ergonomists receive training
supervised by their respective professional organisations.
PMID- 9766910
TI - Prevalence of irritative symptoms in a nonproblem air-conditioned office
building.
AB - OBJECTIVES: To assess the prevalence of work-related complaints and symptoms in
employees in an air-conditioned office building (Building AC) in a mild climatic
area (Italy). No discomfort had previously been reported. METHODS: A total of 198
employees in Building AC and 281 controls working in three naturally ventilated
buildings (Building NV) answered a questionnaire investigating work-related
complaints and symptoms. RESULTS: A significantly higher percentage of workers in
Building AC reported a lack of comfort in the working environment as compared
with the controls (30.6% versus 18.9%). The most common complaints were strong
lighting, high temperature, and dry, dusty, and/or stuffy air. The prevalence of
ocular, upper airway, and cutaneous symptoms was significantly higher (29.8%
versus 14.9%, 25.3% versus 9.6%, and 14.1% versus 3.6%, respectively). No
significant difference was observed in respiratory or general symptoms. Logistic
regression analysis showed that working with video display units and photocopiers
influenced ocular symptoms; upper airway and cutaneous symptoms were influenced
by female gender and working in the air-conditioned building. CONCLUSIONS: In an
apparently healthy air-conditioned office building, complaints and symptoms are
reported more often than in a naturally ventilated edifice, but the prevalence is
lower than that usually observed in sick buildings. Symptoms are influenced by
individual and work-related characteristics.
PMID- 9766911
TI - Assessment of environmental tobacco smoke and respirable suspended particle
exposures for nonsmokers in Prague using personal monitoring.
AB - OBJECTIVE: Exposures to respirable suspended particles (RSP) and environmental
tobacco smoke (ETS) were assessed in Prague, Czech Republic, to determine the
range and degree of personal exposure by means of personal monitoring over a 24-h
period. DESIGN: Self-reported nonsmokers were randomly selected from a
representative sample of the population of Prague. Housewives were recruited into
one group, primarily for assessment exposures in the home, and office workers
were recruited into a second group for assessment of the contribution from the
workplace. METHODS: A total of 238 randomly selected nonsmoking subjects
collected air samples near their breathing zone by wearing personal monitors for
24 h. Samples collected were analyzed for RSP, nicotine, 3-ethenylpyridine, and
ETS particles (using ultraviolet absorbance, fluorescence, and solanesol
measurements). Saliva cotinine analyses were also undertaken to confirm the
nonsmoking status of the subjects. RESULTS: The most highly exposed subjects in
this study were office workers both living and working with smokers. Median time
weighted average exposure concentrations of 60 microg m(-3)RSP, 16 microg m(
3)ETS particles, and 1.6 microg m(-3) nicotine were determined for these
subjects, who also had the highest median saliva cotinine level of 2.4 ng ml(-1).
Housewives living in nonsmoking households were the least exposed subjects in
this study, showing levels of 32 microg m(-3) RSP, 0.17 microg m(-3) ETS
particles, and 0.15 microg m(-3) nicotine. As based upon median levels of ETS
particles and nicotine, no group would potentially inhale or be exposed to more
than 10 cigarette equivalents per year (CE/y) and the least exposed would inhale
less than 1 CE/y. The most highly exposed (90th percentile levels) nonsmokers in
this study, who both worked and lived with smokers, would potentially inhale up
to 29 CE/y. Overall, the workplace was estimated to contribute between 45% and
49% of the annual exposure to nicotine and ETS particles, respectively. On the
basis of determined saliva cotinine concentrations, a misclassification rate of
between 1.7% and 2.5% was calculated. CONCLUSION: Highest exposures were apparent
for office workers both working and living in smoking environments. and our
findings suggest a significant contribution to overall ETS particle and nicotine
levels from the workplace where smoking takes place. Overall, the rates at which
subjects were determined to have misclassified their smoking status in this study
were the lowest observed in any of the European cities investigated to date.
Clearly, a more sensitive method of analysis for cotinine in body fluids is
needed for more accurate determination of the levels expected for nonsmokers.
PMID- 9766912
TI - Exposure to methyl tert-butyl ether and tert-amyl methyl ether from gasoline
during tank lorry loading and its measurement using biological monitoring.
AB - OBJECTIVE AND METHODS: The exposure of Finnish tank lorry drivers to methyl tert
butyl ether (MTBE) and tert-amyl methyl ether (TAME) during loading of gasoline
was studied using biological and breathing-zone sampling. During the field
measurements in October 1994 and August 1995 the gasolines (95, 98, 99 RON)
contained MTBE to 5.2-11.8% and TAME to 0-6%. RESULTS: The geometric mean (GM)
breathing-zone concentration of MTBE was 4.3 mg/m3 (n = 15) in October and 6.4
mg/m3 (n = 20) in August. The GM concentration of TAME, measured only in August,
was 0.98 mg/m3. The mean loading/sampling times were 37 and 35 min, the mean wind
speeds were 0.8 and 0.6 m/s, and the mean air temperatures were -4.9 degrees and
+ 14.1 degrees C, respectively. Blood samples collected on average at 20 min
after gasoline loading/exposure showed an MTBE concentration of 143 nmol/l (GM, n
= 14) in October and 213 nmol/l (GM, n = 20) in August. Pearson's coefficient of
correlation (r) between the MTBE breathing-zone concentrations and MTBE in blood
was 0.86 (P = 0.0001) in October and 0.81 (P = 0.00001) in August. No correlation
was found between MTBE in air and the metabolite tert-butanol (TBA) in blood.
MTBE, but not TBA, in urine samples collected on average at 2.5 h after exposure
showed a correlation with MTBE in air. The concentrations of TAME and its
metabolite tert-amyl alcohol were below the quantitation limits ( < 7 and < 100
nmol/l, respectively) in most blood and urine samples. CONCLUSIONS: The breathing
zone measurements showed low levels of exposure to the two oxygenates, the
concentrations being well below the current hygienic standards for MTBE (250-360
mg/m3 for 15 min and 90-180 mg/m3 for 8 h). The linear correlations obtained for
MTBE suggest that MTBE in blood or urine can be adopted as a valid biological
exposure index.
PMID- 9766913
TI - Monitoring of occupational exposure to dichloromethane by diffuse vapor sampling
and urinalysis.
AB - OBJECTIVE: The aim of the present study was to develop valid methods for
monitoring of occupational exposure to dichloromethane (DCM). METHODS: Carbon
cloth as an adsorbent in diffusive sampling was tested for its capacity to adsorb
DCM vapor and to retain adsorbed DCM after termination of the exposure. Urine
samples collected from DCM-exposed workers were analyzed for DCM by the head
space technique. After extraction with carbon disulfide, DCM in the cloth was
analyzed on a DB-WAX capillary column by flame-ionization detection gas
chromatography (FID-GC) and DCM in urine was analyzed by electron-capture
detection (ECD)-GC. RESULTS: The diffusive sampling with carbon cloth as an
adsorbent is applicable to 4-h monitoring of exposure to up to 100 ppm DCM vapor.
DCM concentrations detected in end-of-shift urine samples correlated linearly
with time-weighted average DCM concentrations measured in the breathing-zone air
of the exposed workers; essentially the same exposure-excretion relationship was
obtained by vapor monitoring for the afternoon 4-h period as compared with a
whole day (8-h) of vapor monitoring. There was no sex difference in the exposure
excretion relation. CONCLUSIONS: Both personal diffusive sampling (at up to 100
ppm DCM and for up to 4 h) and biological exposure monitoring by urinalysis for
DCM are applicable in occupational health as reliable measures of exposure to
this chlorinated hydrocarbon solvent.
PMID- 9766914
TI - Elevated liver enzyme activity in construction workers: prevalence and impact on
early retirement and all-cause mortality.
AB - BACKGROUND: Gamma-glutamyl transferase (GGT), alanine transaminase (ALT), and
aspartate transaminase (AST) are widely used as markers of hepatobiliary
disorders in occupational health surveillance. Little is known, however, about
the prevalence and occupational and non-occupational determinants of elevated
levels of these enzymes in specific occupational groups or about the prognostic
value of elevated levels with respect to long-term outcomes such as all-cause
mortality and vocational disability. METHODS: A cohort study was conducted among
8,043 male construction workers aged 25-64 years who had undergone occupational
health examinations in 6 centers in southern Germany from 1986 to 1988 and had
been followed until 1994. The prevalence of elevated levels of GGT, ALT, and AST,
depending on the sociodemographic and medical characteristics determined at the
baseline examination and the risk of vocational disability and all-cause
mortality in relation to elevated liver enzyme activity at baseline were
assessed. Covariates considered in multivariate analysis included age,
nationality, occupation, body mass index (BMI), smoking, and alcohol consumption.
RESULTS: The baseline prevalence of elevated activity levels of GGT (>28 U/1 at
25 degrees C), ALT (>22 U/1), and AST (>18 U/1) was 32%, 22%, and 12%,
respectively. Factors most strongly related to elevated serum activity levels for
all three enzymes were self-reported alcohol consumption, diabetes, and
hypertension. BMI was strongly associated with elevations in GGT and ALT but not
in AST. Elevated levels of AST and GGT were strongly related to early retirement
and all-cause mortality. Men with AST levels exceeding 18 U/1 had a 2-fold risk
of early retirement and a 3 times higher risk of all-cause mortality as compared
with men with lower AST levels. No significant association was observed between
ALT and either of the long-term outcomes. CONCLUSIONS: Our findings suggest that
screening for elevated GGT and AST levels, which are a common finding among
construction workers, may be a powerful tool for the identification of
individuals at increased risk of early retirement and preterm mortality and may
be helpful in targeting of prevention efforts.
PMID- 9766915
TI - Effect of environmental temperature on the interactive developmental toxicity of
radiofrequency radiation and 2-methoxyethanol in rats.
AB - OBJECTIVE: This research was conducted to determine if altered environmental
temperatures would affect the interactive developmental toxicity of
radiofrequency (RF) radiation and the industrial solvent, 2-methoxyethanol (2ME).
This is important because RF radiation is used in a variety of workplaces that
have poorly controlled environmental temperatures, and many workers are
concurrently exposed to various chemicals. Furthermore, we have previously
demonstrated that combined exposure to RF radiation (10 MHz) and 2ME produces
enhanced teratogenicity in rats. METHODS: RF radiation sufficient to maintain
colonic temperatures at the control value (38degrees ), 39.0degrees or 40.0
degrees C for 2 or 4 h combined with either 0 or 100 mg/ kg 2ME at environmental
temperatures of 18 degrees , 24 degrees and 30 degrees C (65 degrees , 75 degrees
, and 85 degrees F) were given on gestation day 13 to Sprague-Dawley rats. Dams
were killed on gestation day 20, and the fetuses were examined for external
malformations. RESULTS AND CONCLUSIONS: Environmental temperature does affect the
specific absorption rate (SAR) necessary to maintain a specific colonic
temperature but does not affect the interactive developmental toxicity of RF
radiation and 2ME in rats. These results, consistent with the literature, add to
the evidence that the developmental toxicity of RF radiation (combined or alone)
is associated with colonic temperature, not with SAR.
PMID- 9766916
TI - Distribution of nickel in lungs from former nickel workers.
AB - OBJECTIVE: The purpose of this work was to study the distribution of nickel
within lung tissue obtained from nickel-exposed people and to evaluate the use of
only one single sample for determination of the nickel burden of the lung.
METHODS AND MATERIALS: The material used was lung tissue obtained from 15 former
nickel refinery workers who had been exposed to a variety of nickel compounds
such as Ni3S2, NiO, Ni0, NiSO4, and NiCl2. Ten samples taken from different
locations of the lung as well as from the right and left bronchus and from the
right lower lobe (total 13 samples per individual) were analyzed for nickel by
electrothermal atomic absorption spectrometry. Samples obtained from ten people
not connected to the refinery served as a reference group. RESULTS: The
arithmetic mean value +/-SD for nickel concentration was 50+/-150 microg g(-1)
dry wt. Biopsies collected on the center of the lower right lobe had an average
nickel concentration of 82+/-252 microg g(-1). The average nickel concentration
detected in the right and left bronchus was 5.9+/-11.6 and 3.8+/-6.0 microg g(
l), respectively. Lung tissue obtained from ten people not connected to the
refinery had an average nickel concentration of 0.74+/-0.44 microg g(-1).
CONCLUSIONS: The significant findings based on log-normal distribution of the
nickel concentration were as follows: (1) samples obtained from the right lung
showed no significant difference from samples taken from the left lung-a
comparison of the nickel concentration detected in all the lung lobes showed that
no single lobe differed from another; (2) the concentration of nickel found in
the main bronchus of the refinery workers, although elevated, was significantly
lower than the concentration detected in the remaining tissue; and (3) one single
biopsy did not reflect the nickel burden of the lung.
PMID- 9766917
TI - Job strain and arterial blood pressure, serum cholesterol, and smoking as risk
factors for coronary heart disease in Japan.
AB - OBJECTIVE: To determine the effects of the job demands-control model on arterial
blood pressure, serum total cholesterol, and smoking in male daytime and rotating
shift workers in Japan. METHODS: The survey was conducted for all employees of an
electrical factory in Japan using a mailed questionnaire concerning three job
stressors, i.e., job overload, work-pace control, and work-site social support. A
blood sample was taken at the same time. Data on 1703 male daytime workers and 1
173 male rotating-shift workers were analyzed. Multiple logistic regression or
analysis of covariance (ANCOVA) were employed to determine the effects of the job
stressors on systolic and diastolic blood pressure, serum total cholesterol, and
smoking with control for other covariates. RESULTS: Among daytime workers,
systolic and diastolic blood pressures were highest in the "high-strain" (i.e.,
higher job overload + lower work-pace control) group; ANCOVA indicated that a two
way interaction between job overload and work-pace control was significant (P <
0.01). This tendency was not observed among rotating-shift workers. The number of
cigarettes smoked per day was greater in groups with lower work-pace control and
lower work-site social support among daytime workers (two-way interaction between
these two job stressors, P < 0.05); it was greater in groups with lower work-site
social support among rotating-shift workers (main effect of work-site social
support, P < 0.05). CONCLUSIONS: Our study suggest that job strain as defined in
the job demands-control model is associated with increased systolic and diastolic
blood pressures in male daytime workers in Japan. Smoking might be affected by
lower work-site social support.
PMID- 9766918
TI - Hairy cell leukemia. What is new forty years after the first description?
AB - Hairy cell leukemia represent 2% of all the leukemias. The etiology is unknown.
The diagnosis is based on the peripheral blood examination, showing
characteristic lymphoid B cells, with loose lacy chromatin and unconstant
cytoplasmic projections. The abnormal lymphoid cells express CD19, CD20, CD22,
CD79a, CD25 and CD103. The tumor cells are Sig + with clonal light chain
restriction. The treatment is based on recombinant IFN: we discuss the interest
and the risks of second malignancy related to the prescription of the purine
analogues.
PMID- 9766919
TI - Clinical, morphological, cytogenetic and molecular aspects of a series of Ph
negative chronic myeloid leukemias.
AB - Clinical, morphological, cytogenetic and molecular (fluorescence in situ
hybridization and RT-PCR) data were analyzed in twelve Philadelphia negative
chronic myeloid leukemias (Ph-negative CMLs). Four patients were classified as
BCR-positive. A standard b2a2 or b3a2 transcript was found, and the BCR-ABL
hybrid gene was located on the 22q11 band in three cases and on the 1p35 band in
one case with a t(1;9)(p35;q34). All were classified as typical chronic
granulocytic leukemia (CGL) according to the French-American-British (FAB)
morphological guidelines. Responses to therapy were evaluated by FISH in the four
patients, and proved to be poorer than in Ph-positive CMLs. Eight BCR-negative
patients were identified. They could be characterized by an older age, a less
proliferative form of disease than the BCR-positive patients, and a frequent (six
out of eight) abnormal karyotype. The FAB classification identified four CGLs and
four atypical CMLs (aCML). A normal karyotype was more frequent in the patients
classified as CGL whereas all the aCMLs had a chromosomal abnormality. Three
patients had chromatin clumping and this morphologic feature was associated with
trisomy 8 in two. No correlation between the cytogenetic, morphologic and the
clinical data were found. Five patients had poor tolerance to therapy with a
frequent occurrence of bone marrow failure and hemorragic syndrome, whereas three
patients responded to a standard treatment of CML. Our study reinforces previous
data on Ph-negative BCR-positive CMLs and emphasizes the difficulty in
correlating clinical, morphologic, cytogenetic data in Ph-negative BCR-negative
CMLs. However, our data also argue in favor of the existence of true Ph-negative
BCR-negative CMLs and suggest that some of them can respond to a standard
treatment of CML.
PMID- 9766920
TI - Epidemiological data in polycythaemia vera: a study of 842 cases.
AB - An epidemiological study of 842 polycythaemic patients (entered between 1980 and
1997 in the French investigational prospective protocols) is presented. The
global incidence is approximately 0.8-1.5/100,000/year in the reference area (Ile
de-France and surrounding areas). It increases linearly with age until 80, which
suggests that several mutational somatic events are necessary. There was a slight
male excess (sex-ratio 1.2, after correction for the percentage of male and
female French people still living at risk). We did observe a slight excess of PV
in the population of Jewish ancestry. A surprising excess of former blood donors
(20.7% of the PV cases, compared to 8% estimated in the reference population) was
observed. Only a few cases of familial myeloproliferative diseases and occurence
of leukemia in the family of our patients have been observed; even if slight,
this excess is statistically significant. In contrast, no excess of carcinomas
was observed either in the family or in the patients' antecedents. We did not
find any excess of radiation exposure in our cases. When analysing the previous
occupation of our patients a possible excess of physicians and of patients
previously working in occupations using solvents and glues was found, but this
finding needs confirmation.
PMID- 9766921
TI - Severe infection caused by Stomatococcus mucilaginosus in a neutropenic patient:
case report and review of the literature.
AB - A 24-year-old female, in neutropenic phase after chemotherapy for acute
myelogenous leukemia (on day 15) was admitted in intensive care unit for
infectious pneumonia. Two strains of Stomatococcus mucilaginosus were isolated
from peripheral blood cultures. No microorganisms were yielded from
bronchoalveolar lavage. Patient's condition improved with prompt instigation of
effective antibiotic therapy. This was the first case of septicemia and
pneumonia, due to Stomatococcus mucilaginosus, in our unit. Only 26 cases
occurring in neutropenic patients with underlying hematologic malignancies were
reported in the literature and among these, only five cases with pneumonia were
described. The complications of this normal inhabitant of the human oral cavity
can be serious and fatal: septic shock, meningitis, acute respiratory distress
syndrome. This study illustrate the possible virulence of Stomatococcus
mucilaginosus in neutropenic patients.
PMID- 9766922
TI - Prognostic and diagnostic value of endogenous erythroid colony formation in
essential thrombocythemia.
AB - Endogenous erythroid colonies (EECs), a typical characteristic of polycythemia
vera (PV), could be observed in essential thrombocythemia (ET). Erythroid
progenitors culture carried out in 34 previously untreated patients with
unequivocal ET showed EECs in 35% of the cases. During a mean follow up of 4
years after the culture, the 12 EECs(+) and the 22 EECs(-) patients did not show
any difference for a thrombotic or haemorrhagic complication, and the only one
patient who showed an involvement of erythropoiesis was in the EECs(-) group.
PMID- 9766923
TI - Screening of cobalamin metabolism in methotrexate-treated psoriatics.
PMID- 9766924
TI - SCAR 98. Proceedings of the 15th symposium for computer applications in
radiology: filmless radiology--reengineering the practice of radiology for the
21st century. Baltimore, Maryland, USA. June 4-7, 1998.
PMID- 9766925
TI - Recent Advances in Surfactant Research. Proceedings and abstracts of the 13th
International Workshop on Surfactant Replacement. Belfast, September 12, 1998.
PMID- 9766926
TI - [Prevention, screening, and management of cancer of the colon. Agence Nationale
d'Accreditation et d'Evaluation en Sante].
PMID- 9766927
TI - Society for Research on Nicotine and Tobacco. Third Annual Scientific Conference,
Nashville, Tennessee, USA, 13-14 June 1997.
PMID- 9766928
TI - New drug treatments for alcohol problems. Response to Moncrieff & Drummond.
PMID- 9766929
TI - Plucked hair samples as a source of DNA: reliability of dinucleotide
microsatellite genotyping.
AB - To test whether plucked hairs are a reliable source of DNA for genotyping
microsatellite loci, we carried out experiments using one, three, or 10 hairs per
extract for 50 alpine marmots. For each extract, seven independent genotypings
were performed for the same locus (multiple-tubes approach). Two types of
genotyping errors were recorded: a false homozygote defined as the detection of
only one allele of a true heterozygote, and a false allele defined as a PCR
generated allele that was not one of the alleles of the true genotype. Using DNA
extracted from one, three, or 10 hairs the overall error rate was 14.00%, 4.86%,
and 0.29%, respectively. Based on our results, we conclude that 10 hairs should
be used to obtain consistently reliable genotypings using the single-tube
approach, and that a single plucked hair could represent a reliable source of DNA
if the multiple-tubes approach is used. For future studies of dinucleotide repeat
diversity using DNA extracted from one to three shed or plucked hairs, we
strongly recommend initiating an appropriate pilot study to quantify the error
rate and to determine the reliability of the single-tube approach.
PMID- 9766930
TI - Proceedings of the 1st Annual OR-Acquired Pressure Ulcer Symposium. Atlanta,
Georgia, USA.
PMID- 9766931
TI - Establishing a Medical Research Agenda for Child Sexual Abuse: An Invitational
Conference. Solitude, Utah, USA. May 16-17, 1997. Proceedings.
PMID- 9766932
TI - Taking the p... therapeutic proteins from urine.
PMID- 9766933
TI - [Fifty years after the creation of the chair at the Medical School of Bucharest].
PMID- 9766934
TI - Automated 3-dimensional computed tomographic and fluoroscopic image registration.
AB - The registration of 3-dimensional (3-D) anatomical surfaces to sensor data such
as intraoperative fluoroscopy is one of the basic problems in computer integrated
surgery. The main objective is to find the relationship between 3-D preoperative
computed tomographic images and a pair of intraoperative fluoroscopic images.
Consequently, surgical navigation devices can use this relationship to provide
improved surgical guidance. The proposed registration strategy presents a
noninvasive anatomy-based (frameless) method for registration. In this article,
we propose a cooperative approach between registration and contour segmentation
on fluoroscopy. This approach is based on the duality between registration and
segmentation in a model-based vision system. It associates a likelihood value to
each pixel that corresponds to the probability that the pixel belongs to the
contour of the object of interest. The registration is then achieved between
backprojection lines stemming from likely contour pixels and the 3-D surface
model of the object of interest. Then, in order to take into account the internal
contour points extracted by the cooperative approach, we propose a new line to
surface distance computation algorithm to be used during the data to model
distance minimization step. Finally, we present the obtained results that
demonstrate the validity of the proposed approach in carrying out accurate 3-D
and 2-D registration.
PMID- 9766935
TI - Hepatitis B vaccination of patients with chronic liver disease.
PMID- 9766936
TI - Patient survival after tertiary liver transplantation.
PMID- 9766937
TI - Helmut Heydt--friend and counsellor.
PMID- 9766938
TI - The EDSP: setting the stage!
PMID- 9766940
TI - Taking the ocean's temp.
PMID- 9766939
TI - Plant lectins: specific tools for the identification, isolation, and
characterization of O-linked glycans.
PMID- 9766941
TI - A move for the better.
PMID- 9766942
TI - A gray area of environmental justice.
PMID- 9766943
TI - A nice cup of tea.
PMID- 9766944
TI - A breath of fresh air.
PMID- 9766945
TI - Double-edged sword.
PMID- 9766946
TI - Bug spray worse than the bite?
PMID- 9766947
TI - Ambivalent antihistamines.
PMID- 9766948
TI - Meeting of the cancer minds.
PMID- 9766949
TI - Taking the lead on lead.
PMID- 9766950
TI - To MTBE or not to MTBE.
PMID- 9766951
TI - Decade of the brain: the gray area of research on gray matter.
PMID- 9766952
TI - Environmental impact on hearing: is anyone listening.
PMID- 9766953
TI - Methyl bromide under fire.
PMID- 9766954
TI - Vets may be compensated.
PMID- 9766955
TI - Poland's environmental docs.
PMID- 9766956
TI - Cigarette secrets.
PMID- 9766957
TI - World Wildlife funds for Russia and Asia.
PMID- 9766958
TI - Cystic fibrosis: present and future.
AB - Cystic fibrosis (CF) is an inherited disorder of epithelial chloride transport
affecting primarily pancreas, lungs, gut, liver and exocrine glands. The defect
is caused by defects of the cystic fibrosis transmembrane regulation gene on
chromosome 7. Genotyping has proved useful in identifying gene carriers, a
definitive diagnosis, and in antenetal diagnosis. Genotype/phenotype
relationships have shown that the commonest cause of pancreatic insufficiency is
the D F508 mutation. Clinical trials are exploring the use of somatic gene
therapy but this is not yet a viable treatment option. Liver, lung and intestinal
disease result in malnutrition which causes further dysfunction of these organs.
Aggressive nutritional and pancreatic enzyme therapy results in improved disease,
normal growth and increased survival. However, high-dose enzyme therapy may in
some individuals cause a fibrosing colonopathy. For those with end-stage liver
and lung disease, transplantation holds out some hope.
PMID- 9766959
TI - The amount and pattern of DNA polymorphism under the neutral mutation hypothesis.
AB - The amount and pattern of DNA polymorphism can give useful information on the
maintenance mechanism of genetic variation at the DNA level. In this note we have
shown the amount and pattern of DNA polymorphism expected under the neutral
theory. The amount of DNA polymorphism can be estimated from the average number
of nucleotide differences per site, the proportion of segregating sites, and so
on. We have shown how to estimate theta from these quantities, where theta = 4Nv,
N is the effective population size and v is the mutation rate per site per
generation. We have also shown the expectations of the nucleotide variation
within and between allelic classes.
PMID- 9766960
TI - Risk of population extinction from fixation of deleterious and reverse mutations.
AB - A model is developed for alternate fixations of mildly deleterious and wild-type
alleles arising by forward and reverse mutation in a finite population. For
almost all parameter values, this gives an equilibrium load that agrees closely
with the general expression derived from diffusion theory. Nearly neutral
mutations with selection coefficient a few times larger than 1/(2N(e)) do the
most damage by increasing the equilibrium load. The model of alternate fixations
facilitates dynamical analysis of the expected load and the mean time to
extinction in a population that has been suddenly reduced from a very large size
to a small size. Reverse mutation can substantially improve population viability,
increasing the mean time to extinction by an order of magnitude or more, but
because many mutations are irreversible the effects may not be large. Populations
with initially high mean fitness and small effective size, N(e) below a few
hundred individuals, may be at serious risk of extinction from fixation of
deleterious mutations within 10(3) to 10(4) generations.
PMID- 9766961
TI - Asymmetrical DNA replication promotes evolution: disparity theory of evolution.
AB - Heredity is guaranteed by faithful DNA replication whereas evolution depends upon
errors accompanying DNA replication. This contradiction existing between heredity
and evolution cannot be resolved in an individual organism, but only in terms of
a population, in that a delicate balance exists between wild type and variants in
a population which is necessary for the survival of the species. Namely, there
seems to be a key in the mechanism of DNA replication to solve some problems of
evolution. DNA is replicated semiconservatively using the leading and
discontinuous lagging strands. According to our 'disparity theory of evolution',
the existence of a sufficient fidelity difference between the leading and lagging
strands is advantageous in terms of evolution, because the diversity of genotypes
is enlarged but genotypes that have occurred in the past are guaranteed. In
theory, by artificially increasing the fidelity difference between the leading
and lagging strand ('disparity mutator'), evolution is accelerated while avoiding
the extinction of the population. Using a disparity mutator, we should be able to
improve living things, including multicellular organisms, within constrained
conditions. A double-stranded algorithm, which mimics the structure and
replication manner of DNA, is promising for solving optimization problems.
PMID- 9766962
TI - Clusters of new identical mutants and the fate of underdominant mutations.
AB - Given favorable environmental and demographic conditions, premeiotic clusters of
identical mutations can produce a broad distribution of the initial frequency of
underdominant alleles. Because of these clusters, new underdominant mutations may
not necessarily be as rare in a population as previously assumed. The fixation of
underdominant mutations, especially those with low heterozygous fitness, is
increased when mutations appear in a cluster due to a genetic change that
occurred before germline differentiation. Most restrictions on the fixation of
underdominant mutations in a single population, such as strong genetic drift,
weak selection against mutant heterozygotes, isolated population structure,
inbreeding, meiotic drive, and selection in favor of mutant homozygotes can be
relaxed or even dropped. Instead, the fate of strong underdominant mutations is
determined mainly by ecological and genetic factors that affect the cluster size
distribution of new premeiotic mutations. Accumulation of reproductive isolation
by the fixation of underdominant mutations becomes more feasible with clusters,
and mutation is not always the weakest force during this evolutionary process.
The large mean and variance of reproductive success in many multicellular species
make it possible that even underdominant mutations with very low heterozygous
fitness could contribute substantially to reproductive isolation.
PMID- 9766963
TI - Mutation and selection within the individual.
AB - Selection within the individual may have played a critical and creative role in
evolution, boosting the survival chances of mutations beneficial to the cell and
the individual, hindering the spread of deleterious mutations, and reducing the
genetic load imposed on the population. We review the literature and present new
results to describe the effects of cell-lineage selection on the rate and
fixation probability of new mutations. Cell-lineage selection can alter these
quantities by several orders of magnitude. Cell-lineage selection is especially
important in the case of rare recessive mutations, which are hidden from
selection at the individual level but may be exposed to selection at cellular
level. Because selection within the individual acts as a sieve eliminating
deleterious mutations and increasing the frequency of beneficial ones, mutations
observed among progeny will have been pre-selected and are more likely to
increase cell proliferation than would randomly generated mutations. Although
many authors have focused on the potential conflict between selection at the
cellular and individual levels, it must be much more common that the two levels
act concordantly. When selection at the cell and individual levels act in a
cooperative manner, increased rather than decreased opportunity for germline
selection will be favored by evolution.
PMID- 9766964
TI - A pleiotropic model of phenotypic evolution.
AB - A pleiotropic model is presented for deriving the equilibrium genetic variance by
mutation and stabilizing selection and the long-term genetic responses to
directional selection in the case where mutations have pleiotropic effects on
fitness itself (direct deleterious effect) and on a quantitative trait
(phenotypic effect). The equilibrium genetic variance is derived as a general
form of the rare-alleles models, i.e., [formula: see text], where n is the number
of loci, mu is the per-locus mutation rate, alpha 2 is the variance of new
mutations, V(s) is the measure of stabilizing selection, and s(u) is the
selection coefficient on mutations by direct deleterious effect. The genetic
responses to directional selection is calculated based on the assumption that the
genetic variance is kept at an equilibrium by mutation and stabilizing selection
but without directional selection, and the directional selection starts to
operate on the target trait. The evolutionary rate at the t-th generation after
the introduction of the directional selection is [formula: see text], where i is
the directional selection intensity, and s(T) is the total selection coefficient
on mutations, i.e., [formula: see text]. The selection limit is [formula: see
text], where V(m) is the mutational variance (2n mu alpha 2). The pleiotropic
effects of genes reduce both the evolutionary rate and the selection limit.
PMID- 9766965
TI - Genetic measurement of theory of epistatic effects.
AB - Epistasis is defined as the influence of the genotype at one locus on the effect
of a mutation at another locus. As such it plays a crucial role in a variety of
evolutionary phenomena such as speciation, population bottle necks, and the
evolution of genetic architecture (i.e., the evolution of dominance,
canalization, and genetic correlations). In mathematical population genetics,
however, epistasis is often represented as a mere noise term in an additive model
of gene effects. In this paper it is argued that epistasis needs to be scaled in
a way that is more directly related to the mechanisms of evolutionary change. A
review of general measurement theory shows that the scaling of a quantitative
concept has to reflect the empirical relationships among the objects. To apply
these ideas to epistatic mutation effects, it is proposed to scale A x A
epistatic effects as the change in the magnitude of the additive effect of a
mutation at one locus due to a mutation at a second locus. It is shown that the
absolute change in the additive effect at locus A due to a substitution at locus
B is always identical to the absolute change in B due to the substitution at A.
The absolute A x A epistatic effects of A on B and of B on A are identical, even
if the relative effects can be different. The proposed scaling of A x A epistasis
leads to particularly simple equations for the decomposition of genotypic
variance. The Kacser Burns model of metabolic flux is analyzed for the presence
of epistatic effects on flux. It is shown that the non-linearity of the Kacser
Burns model is not sufficient to cause A x A epistasis among the genes coding for
enzymes. It is concluded that non-linearity of the genotype-phenotype map is not
sufficient to cause epistasis. Finally, it is shown that there exist correlations
among the additive and epistatic effects among pairs of loci, caused by the
inherent symmetries of Mendelian genetic systems. For instance, it is shown that
a mutation that has a larger than average additive effect will tend to decrease
the additive effect of a second mutation, i.e., it will tend to have a negative
(canalizing) interaction with a subsequent gene substitution. This is confirmed
in a preliminary analysis of QTL-data for adult body weight in mice.
PMID- 9766966
TI - Requisite mutational load, pathway epistasis and deterministic mutation
accumulation in sexual versus asexual populations.
AB - A measure of the equilibrium load of deleterious mutations is developed that
explicitly incorporates the level of genome-wide linkage disequilibrium. This
measure, called the requisite mutational load, is based on the minimal net
reproductive rate of the least mutated class necessary to prevent the
deterministic mutation accumulation. If this minimal net reproductive rate is
larger than ecological or physiological constraints allow, then: a) the
population is driven to extinction via deterministic mutation accumulation, or b)
a mutational Red-Queen ensues with adaptation counterbalancing mutation
accumulation. Two population parameters determine the requisite mutational load:
a) the equilibrium strength of selection, measured as a selection gradient, and
b) the equilibrium opportunity for selection, measured as the variance in number
of mutations per genome. The opportunity for selection is decomposed into the
accumulation of mutations (average number per genome) and the level of genome
wide linkage disequilibrium. Recombination can substantially reduce the requisite
mutational load, compared to clonal reproduction, when there is buffering and/or
reinforcing epistasis and also when there is positive assortative mating for
fitness. Recombination is advantageous because it reduces the negative (variance
reducing) linkage disequilibrium induced by beneficial epistasis. The functional
form of the expression for requisite mutational load illustrates why epistasis
within pathways, i.e., among closely interacting genes, is a powerful alternative
to genome-wide truncation selection, as a means of reducing mutational load.
PMID- 9766967
TI - Identification of four alternatively spliced isoforms of chicken casein kinase I
alpha that are all expressed in diverse cell types.
AB - Casein kinase I (CKI) is a family of widely expressed protein kinases. It is
previously shown in mammalian tissues that CKIalpha exists as two or three
alternatively spliced isoforms (Rowles et al.,1991; Zhang et al., 1996; Kuret et
al., 1997). We now report that four alternatively spliced isoforms of CKIalpha
are expressed in many chicken cells and tissues. A partial cDNA clone was
isolated from a chicken brain library, using a probe derived from a bovine
CKIalpha cDNA. The translated sequence of this clone was 100% identical to the
bovine homolog containing the 'L' insert, with the addition of 12 amino acids
just before the C terminus that had previously been reported in human and Xenopus
CKIalpa. After completing the missing portion of the coding sequence by 5' RACE
(rapid amplification of cDNA ends), full-length cDNA was PCR amplified from
chicken brain cDNA, yielding four different products. These were cloned and
sequenced and found to correspond to the four CKIalpha isoforms: CKIalpha,
CKIalphaL, CKIalphaS and CKILalphaLS, where 'S' is the insert consisting of the
12 human/Xenopus C-terminal amino acids. Using reverse transcription and
polymerase chain reaction (Rt-PCR), it was shown that the four isoforms are all
expressed in neurons, fibroblasts and several tissues. This represents the first
demonstration that four splice variants exist and are all expressed in a single
type of cell.
PMID- 9766968
TI - Inducible expression of green fluorescent protein within channel catfish cells by
a cecropin gene promoter.
AB - The activity of an insect promoter of the cecropin B gene (Cec B) was
investigated using green fluorescent protein (gfp) as a reporter in cells of
channel catfish (Ictalurus punctatus). The expression vector pQZ-1 containing the
Cec B promoter and a modified gfp cDNA sequence was delivered by lipofection to
three catfish types: fibroblast and leukocyte cell lines, and primary cultures of
leukocytes. No resistance genes were included in the vector for selection of GFP
expressing cells. The GFP mRNA was detected in all three cell types with 5 to 10
times higher concentrations observed in leukocytes than in fibroblasts.
Expression was enhanced with the addition of irradiated Flavobacterium columnare
(7.0 ?10(6) cells/ml) or Escherichia coli LPS (125microgram/ml). Quantitative RT
PCR showed GFP mRNA reached maximum levels 24h after bacterial challenge in
fibroblast cells, and at 10-12h after LPS challenge in fibroblasts and
leukocytes. The number of fibroblasts expressing GFP increased by 0.8%, and the
average of green fluorescence intensity increased by 52.8%, whereas the increase
in leukocytes was 0.13% in cell number and 3.4% in fluorescence intensity. These
results suggest that the transcription of the Cec B promoter in channel catfish
cells exhibited an inducible pattern and could be placed under the control of the
immune system (in vivo). The mechanisms for endogenous activation of the Cec B
promoter and for production of gfp RNA in unchallenged cells remain to be
studied.
PMID- 9766969
TI - International Society for Pediatric and Adolescent Diabetes 24th annual meeting.
Zurich, Switzerland, September 14-17, 1998. Abstracts.
PMID- 9766971
TI - Proceedings of an International Conference on Dehydration, Rehydration and
Exercise in the Heat. Nottingham, England, November 1-5, 1995.
PMID- 9766970
TI - Very early thrombolysis in acute myocardial infarction and pulmonary embolism
disease. Symposium proceedings. Ravenna, Italy, April 1996.
PMID- 9766972
TI - A retrospective study of promethazine and its failure to produce the expected
incidence of sedation during space flight.
AB - Since March 1989, intramuscular (IM) promethazine has been successfully used to
treat the symptoms of space motion sickness. The incidence of sedation associated
with promethazine administration on the ground is large and may result in
operational impact. The authors undertook a retrospective study to quantify the
incidence of sedation from promethazine use during Space Shuttle flights. Crew
medical debriefings from 14 shuttle missions were reviewed for crew members who
had been treated with IM promethazine and their corresponding symptoms were
identified. Twenty-one crew members received IM promethazine (25-50 mg), and only
one experienced any associated sedation with no operational impact. This sedation
incidence of less that 5% is in stark contrast to the 60 to 73% incidence of
sedation seen in ground-based studies. The incidence of sedation during space
flight from IM promethazine is substantially less than that seen on the ground
and does not present an operational problem during Space Shuttle flights. Future
investigations of environmental stressors and pharmacodynamic changes associated
with space flight may explain the huge disparity between the space-flight and
ground-based data.
PMID- 9766973
TI - Gammaherpesvirus sequence comparisons.
PMID- 9766974
TI - Functional interaction of human immunodeficiency virus type 1 Vpu and Gag with a
novel member of the tetratricopeptide repeat protein family.
PMID- 9766975
TI - Murine leukemia virus envelope protein in transgenic-mouse serum blocks infection
in vitro.
PMID- 9766976
TI - [Oncological lymph node sampling in lung cancer].
PMID- 9766977
TI - The effects of a continuing medical education programme in interpersonal
communication skills on doctor practice and patient satisfaction in Trinidad and
Tobago.
AB - This study investigates the effects of a brief training programme on the
communication skills of doctors in ambulatory care settings in Trinidad and
Tobago. Evaluation of doctor performance is based on analysis of audiotapes of
doctors with their patients during routine clinic visits and on patient
satisfaction ratings. A pre-test/post-test quasi-experimental study design was
used to evaluate the effects of exposure to the training programme. Doctors were
assigned to groups based on voluntary participation in the programme. Audiotapes
of the 15 participating doctors (nine trained and six control) with 75 patients
at baseline and 71 patients at the post-training assessment were used in this
analysis. The audiotapes were content-coded using the Roter Interaction Analysis
System (RIAS). Doctors trained in communication skills used significantly more
target skills post-training than their untrained colleagues. Trained doctors used
more facilitations in their visits and more open-ended questions than other
doctors. There was also a trend towards more emotional talk, and more close-ended
questions. Patients of trained doctors talked more overall, gave more information
to their doctors and tended to use more positive talk compared to other patients.
Trained doctors were judged as sounding more interested and friendly, while
patients of trained doctors were judged as sounding more dominant, responsive and
friendly than patients of untrained doctors. Consistent with these communication
differences, patient satisfaction tended to be higher in visits of trained
doctors.
PMID- 9766978
TI - Effect of diuretics on sodium and chloride permeability in the rat papillary
collecting duct.
AB - While in vivo data suggests that diuretics such as furosemide and
hydrochlorothiazide alter inner medulla collecting duct (IMCD) cell electrolyte
transport, this has not been confirmed by in vivo studies nor have the mechanisms
been evaluated. This study evaluated the direct effect of these diuretics as well
as amiloride on sodium and chloride unidirectional permeability in the isolated
perfused rat IMCD. In the absence of diuretics, the permeability of sodium was
lower than that of chloride (0.63 +/- 0.05 compared with 0.83 +/- 0.08
micrometer/s), although both were relatively impermeable when compared to water.
Furosemide (10(-4)) and hydrochlorothiazide (10(-3)) both increased the
diffusional permeability of chloride by approximately 30% (0.80 +/- 0.06 to 1.04
+/- 0.09 micrometer/s, p < 0.01, and 0.74 +/- 0.09 to 0.98 +/- 0.10 micrometer/s,
p < 0.02, respectively). However, sodium permeability was unaltered. Inhibition
of Na+, K+-ATPase by ouabain or cooling (4 degrees C) inhibited basal sodium but
not chloride permeability while a maximal antidiuretic AVP concentration did not
alter sodium or chloride permeability. However, increasing the lumen and bath
sodium chloride concentration from 150 to 300 and 600 mM significantly increased
both sodium and particularly chloride conductance. In contrast, amiloride (10(
4)) significantly reduced both sodium and chloride permeability. These studies
support a direct effect of furosemide and hydrochlorothiazide on the IMCD and
suggest that their in vivo effect is primarily mediated by facilitating the
passive movement of chloride into the lumen via a favourable electrochemical
gradient. These results also demonstrate that amiloride inhibits both sodium and
chloride unidirectional permeability by mechanisms separate to that of the
sulphonamide-related diuretics.
PMID- 9766979
TI - Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.
PMID- 9766980
TI - Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.
PMID- 9766981
TI - Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.
PMID- 9766982
TI - Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.
PMID- 9766983
TI - Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.
PMID- 9766984
TI - Endometriosis in the thoracic aorta.
PMID- 9766985
TI - Dialysis therapy.
PMID- 9766986
TI - Dialysis therapy.
PMID- 9766987
TI - Dialysis therapy.
PMID- 9766988
TI - Dialysis therapy.
PMID- 9766989
TI - More on acid-base disorders.
PMID- 9766990
TI - The rewards of reading instructions from journal editors.
PMID- 9766991
TI - Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.
PMID- 9766992
TI - Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer.
PMID- 9766993
TI - Antituberculosis-drug resistance.
PMID- 9766994
TI - Antituberculosis-drug resistance.
PMID- 9766995
TI - Antituberculosis-drug resistance.
PMID- 9766996
TI - Augmented post-induction therapy in childhood lymphoblastic leukemia.
PMID- 9766997
TI - Acute diverticulitis.
PMID- 9766998
TI - Acute diverticulitis.
PMID- 9766999
TI - Acute diverticulitis.
PMID- 9767000
TI - Acute diverticulitis.
PMID- 9767001
TI - Cardiovascular risk factors and atherosclerosis in children and young adults.
PMID- 9767002
TI - Diagnosis of pulmonary embolism.
PMID- 9767003
TI - Diagnosis of pulmonary embolism.
PMID- 9767004
TI - Diagnosis of pulmonary embolism.
PMID- 9767005
TI - Diagnosis of pulmonary embolism.
PMID- 9767007
TI - Laboratory Behavioral Studies of Vulnerability to Drug Abuse. Proceedings of a
meeting. August 2-3, 1994.
PMID- 9767006
TI - Inhibition of the adherence of P-fimbriated Escherichia coli to uroepithelial
cell surfaces by proanthocyanidin extracts from cranberries.
PMID- 9767008
TI - Problems of drug dependence 1997: proceedings of the 59th annual scientific
meeting.
PMID- 9767009
TI - Correction. CTL induction by a tumour-associated antigen octapeptide derived from
a murine lung carcinoma.
PMID- 9767010
TI - Retracted correction. CTL induction by a tumour-associated antigen octapeptide
derived from a murine lung carcinoma.
PMID- 9767011
TI - Future perfect.
PMID- 9767012
TI - A multidisciplinary approach to palliative transfusions at home.
PMID- 9767013
TI - Cleaning up our practice.
PMID- 9767014
TI - Electronic publishing can bring your work to life. Augmenting content with
multimedia highlights and links.
PMID- 9767015
TI - Cattle diet linked to bacterial growth.
PMID- 9767016
TI - Senate Committee votes boost for NIH.
PMID- 9767017
TI - RNA-splicing machinery revealed.
PMID- 9767018
TI - Leptin sparks blood vessel growth.
PMID- 9767019
TI - Transfer of Protein Data Bank sparks concern.
PMID- 9767020
TI - Five researchers die in plane crash.
PMID- 9767021
TI - The cerebellum: the brain's engine of agility.
PMID- 9767022
TI - Multiplying knowledge of cell division, plant growth.
PMID- 9767023
TI - Quiescence in nuclear transfer.
PMID- 9767024
TI - The future of long life.
PMID- 9767025
TI - The future of long life.
PMID- 9767026
TI - The future of long life.
PMID- 9767027
TI - The paradox of lead poisoning prevention.
PMID- 9767028
TI - Reward for persistence in substance P research.
PMID- 9767031
TI - Raising the stakes in the race for new malaria drugs.
PMID- 9767029
TI - Routing MAP kinase cascades.
PMID- 9767032
TI - Semiconductor beacons light up cell structures.
PMID- 9767033
TI - Lasker Awards go to cancer researchers.
PMID- 9767034
TI - A biomolecule building block from vents.
PMID- 9767035
TI - Two more scientists died in Swissair crash.
PMID- 9767036
TI - Fly development genes lead to immune find.
PMID- 9767037
TI - Protecting medicine in the 21st century.
PMID- 9767038
TI - A revolution in evolution.
PMID- 9767039
TI - Cleaning CJD-contaminated instruments.
PMID- 9767040
TI - Salt wars.
PMID- 9767041
TI - Salt wars.
PMID- 9767042
TI - Salt wars.
PMID- 9767043
TI - Salt wars.
PMID- 9767044
TI - Salt wars.
PMID- 9767045
TI - Salt wars.
PMID- 9767046
TI - Crystallography of a photocycle intermediate.
PMID- 9767047
TI - The saturation debate.
PMID- 9767048
TI - The evolution of sex.
PMID- 9767049
TI - Why sex? Putting theory to the test.
PMID- 9767050
TI - A new look at monogamy.
PMID- 9767051
TI - A genomic battle of the sexes.
PMID- 9767052
TI - [Resection margins after lumpectomy (tumorectomy) and much more].
PMID- 9767053
TI - Mechanisms of cartilage destruction: onset of osteoarthritis research in Germany.
Kloster Seeon, February 27-28, 1998. Abstracts.
PMID- 9767054
TI - Proceedings of the annual meeting on Anesthesia and the Geriatric Patient. Gent,
November 28-29, 1997.
PMID- 9767055
TI - Photo quiz. Iron deficiency anemia: What's the cause?
PMID- 9767058
TI - Prostatitis.
AB - The laboratory diagnosis of acute bacterial prostatitis is straightforward and
easily accomplished in clinical laboratories. Chronic bacterial prostatitis, and
especially chronic idiopathic prostatitis (most often referred to as abacterial
prostatitis), presents a real challenge to the clinician and clinical
microbiologist. Clinically, the diagnosis of chronic idiopathic prostatitis is
differentiated from that of acute prostatitis by a lack of prostatic inflammation
and no "significant" (controversial) leukocytes or bacteria in the expressed
prostatic secretions. Despite these diagnostic criteria, the etiology of chronic
idiopathic prostatitis is unknown. While this review covers the entire spectrum
of microbially caused acute prostatitis (including common and uncommon bacteria,
viruses, fungi, and parasites) and microbially associated chronic prostatitis, a
special focus has been given to chronic idiopathic prostatitis. The idiopathic
syndrome is commonly diagnosed in men but is poorly treated. Recent data
convincingly suggests a possible bacterial etiology for the condition.
Provocative molecular studies have been published reporting the presence of 16S
rRNA bacterial sequences in prostate biopsy tissue that is negative for ordinary
bacteria by routine culture in men with chronic idiopathic prostatitis.
Additionally, special culture methods have indicated that difficult-to-culture
coryneforms and coagulase-negative staphylococci are present in expressed
prostatic secretions found to be negative by routine culture techniques.
Treatment failures are not uncommon in chronic prostatitis. Literature reports
suggest that antimicrobial treatment failures in chronic idiopathic prostatitis
caused by organisms producing extracellular slime might result from the virulent
properties of coagulase-negative staphylococci or other bacteria. While it is
difficult to definitively extrapolate from animal models, antibiotic
pharmokinetic studies with a murine model have suggested that treatment failures
in chronic prostatitis are probably a result of the local microenvironment
surrounding the persistent focal and well-protected small bacterial biofilms
buried within the prostate gland. These conclusions support the molecular and
culture data implicating bacteria as a cause of chronic idiopathic prostatitis.
PMID- 9767056
TI - Regulation and function of T-cell-mediated immunity during Toxoplasma gondii
infection.
AB - The intracellular protozoan Toxoplasma gondii is a widespread opportunistic
parasite of humans and animals. Normally, T. gondii establishes itself within
brain and skeletal muscle tissues, persisting for the life of the host.
Initiating and sustaining strong T-cell-mediated immunity is crucial in
preventing the emergence of T. gondii as a serious pathogen. The parasite induces
high levels of gamma interferon (IFN-gamma) during initial infection as a result
of early T-cell as well as natural killer (NK) cell activation. Induction of
interleukin-12 by macrophages is a major mechanism driving early IFN-gamma
synthesis. The latter cytokine, in addition to promoting the differentiation of
Th1 effectors, is important in macrophage activation and acquisition of
microbicidal functions, such as nitric oxide release. During chronic infection,
parasite-specific T lymphocytes release high levels of IFN-gamma, which is
required to prevent cyst reactivation. T-cell-mediated cytolytic activity against
infected cells, while easily demonstrable, plays a secondary role to inflammatory
cytokine production. While part of the clinical manifestations of toxoplasmosis
results from direct tissue destruction by the parasite, inflammatory cytokine
mediated immunopathologic changes may also contribute to disease progression.
PMID- 9767059
TI - Protease inhibitors as antiviral agents.
AB - Currently, there are a number of approved antiviral agents for use in the
treatment of viral infections. However, many instances exist in which the use of
a second antiviral agent would be beneficial because it would allow the option of
either an alternative or a combination therapeutic approach. Accordingly, virus
encoded proteases have emerged as new targets for antiviral intervention.
Molecular studies have indicated that viral proteases play a critical role in the
life cycle of many viruses by effecting the cleavage of high-molecular-weight
viral polyprotein precursors to yield functional products or by catalyzing the
processing of the structural proteins necessary for assembly and morphogenesis of
virus particles. This review summarizes some of the important general features of
virus-encoded proteases and highlights new advances and/or specific challenges
that are associated with the research and development of viral protease
inhibitors. Specifically, the viral proteases encoded by the herpesvirus,
retrovirus, hepatitis C virus, and human rhinovirus families are discussed.
PMID- 9767057
TI - Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods,
and pathogenicity factors.
AB - Bacteria belonging to the genus Klebsiella frequently cause human nosocomial
infections. In particular, the medically most important Klebsiella species,
Klebsiella pneumoniae, accounts for a significant proportion of hospital-acquired
urinary tract infections, pneumonia, septicemias, and soft tissue infections. The
principal pathogenic reservoirs for transmission of Klebsiella are the
gastrointestinal tract and the hands of hospital personnel. Because of their
ability to spread rapidly in the hospital environment, these bacteria tend to
cause nosocomial outbreaks. Hospital outbreaks of multidrug-resistant Klebsiella
spp., especially those in neonatal wards, are often caused by new types of
strains, the so-called extended-spectrum-beta-lactamase (ESBL) producers. The
incidence of ESBL-producing strains among clinical Klebsiella isolates has been
steadily increasing over the past years. The resulting limitations on the
therapeutic options demand new measures for the management of Klebsiella hospital
infections. While the different typing methods are useful epidemiological tools
for infection control, recent findings about Klebsiella virulence factors have
provided new insights into the pathogenic strategies of these bacteria.
Klebsiella pathogenicity factors such as capsules or lipopolysaccharides are
presently considered to be promising candidates for vaccination efforts that may
serve as immunological infection control measures.
PMID- 9767062
TI - Pain assessment and evaluation of patients who have neuropathic pain.
AB - Pain assessment and physical examination are the first crucial steps in diagnosis
of neuropathic pain disorders because these are still solely diagnosed on
clinical grounds. The physical examination should be conducted in such a way that
all of the positive sensory phenomena, such as allodynia, hyperalgesia,
hyperpathia, summation, and after-sensation are elicited. Other physical
examination findings should corroborate the diagnostic impression of neuropathic
pain. Specific pain diagnosis should then lead to more specific therapy.
PMID- 9767063
TI - Painful polyneuropathy.
AB - Painful polyneuropathy is one of the most common chronic pain syndromes
neurologists are asked to assess for diagnostic and therapeutic purposes. This
article reviews the most current clinical guidelines, including history, pain
assessment, physical examination findings, treatment recommendations, and
pathophysiologic pain mechanisms underlying this condition. As a result of recent
advances, the understanding and therapy of pain associated with polyneuropathy
has evolved over the past several years and will continue to do so in the years
to come.
PMID- 9767064
TI - Pain caused by herpes zoster infection.
AB - Postherpetic neuralgia (PHN) is a neuropathic pain disorder that occurs most
often in the elderly. This painful condition is uniquely suited for clinical
research, resulting in an emerging understanding of the pathophysiology of the
persistent pain. Until recently, only the tricyclic antidepressants proved
effective for PHN. Controlled trials of a wide variety of therapeutic strategies
are in progress or have been recently completed.
PMID- 9767065
TI - Spinal and radicular pain disorders.
AB - Although most acute conditions of the spine are benign and self-limited, the
economic costs and disability resulting from these disorders have reached
epidemic proportions in industrialized society. Recent scientific research to
determine the causes of common spinal disorders, long attributed to structural
abnormalities, have now implicated complex biochemical and neurophysiologic
processes which may offer insights for future therapy interventions. This article
reviews the functional and pathologic anatomy and correlates with current
diagnostic and nonoperative management strategies for common mechanical spinal
and radicular pain syndromes.
PMID- 9767060
TI - Management of infections due to antibiotic-resistant Streptococcus pneumoniae.
AB - Antibiotic-resistant strains of Streptococcus pneumoniae are becoming more
prevalent throughout the world; this has resulted in modifications of treatment
approaches. Management of bacterial meningitis has the greatest consensus.
Strategies for treating other systemic infections such as pneumonia, bacteremia,
and musculoskeletal infections are evolving, in part related to the availability
of new antibiotics which are active in vitro against isolates resistant to
penicillin and the extended-spectrum cephalosporins. However, there are currently
very limited data related to the clinical efficacy of these new agents. The
studies upon which current recommendations are based are reviewed. Otitis media
represents the single most common infection due to S. pneumoniae. Recommendations
for treatment of acute otitis media due to drug-resistant strains and the
rationale for these recommendations are discussed.
PMID- 9767066
TI - Traumatic neuralgias: complex regional pain syndromes (reflex sympathetic
dystrophy and causalgia): clinical characteristics, pathophysiological mechanisms
and therapy.
AB - Complex regional pain syndromes (CPRS) may develop as a disproportionate
consequence of a trauma affecting the limbs without (CRPS I, reflex sympathetic
dystrophy) or with (CRPS II, causalgia) obvious nerve lesions. The clinical
picture of CRPS consists of asymmetrical distal extremity pain, swelling, and
autonomic (sympathetic) and motor symptoms. Changes in the peripheral and central
somatosensory, autonomic and motor processing, and a pathologic interaction of
sympathetic and afferent systems are discussed as underlying pathophysiologic
mechanisms. Therapeutic strategies include pharmacologic pain relief,
sympatholytic interventions, and rehabilitation.
PMID- 9767067
TI - Neuropathic pain in the cancer patient.
AB - Cancer presents itself in numerous ways, adding to the complexity of any pain
syndrome with which it is associated. Neuropathic pain, unlike many other pain
syndromes, is difficult to treat even in the absence of cancer. The combination
results in a heterogeneous group of patients with a complex set of symptoms. This
makes the assessment of pain, classification of syndromes, and clinical study a
challenge. If the disease is nonprogressive, general principles of care are
essentially the same as in those without cancer. In patients with progressive
disease and more refractory painful conditions, spinal anesthetic and
neurosurgical therapies must often be considered. Under such circumstances,
caregivers are forced to carefully balance uncertain benefits and risks, often
without the luxury of time. More careful observation and controlled trials in
these patients help facilitate this challenging process.
PMID- 9767061
TI - Pneumococcal diversity: considerations for new vaccine strategies with emphasis
on pneumococcal surface protein A (PspA).
AB - Streptococcus pneumoniae is a problematic infectious agent, whose seriousness to
human health has been underscored by the recent rise in the frequency of
isolation of multidrug-resistant strains. Pneumococcal pneumonia in the elderly
is common and often fatal. Young children in the developing world are at
significant risk for fatal pneumococcal respiratory disease, while in the
developed world otitis media in children results in substantial economic costs.
Immunocompromised patients are extremely susceptible to pneumococcal infection.
With 90 different capsular types thus far described, the diversity of pneumococci
contributes to the challenges of preventing and treating S. pneumoniae
infections. The current capsular polysaccharide vaccine is not recommended for
use in children younger than 2 years and is not fully effective in the elderly.
Therefore, innovative vaccine strategies to protect against this agent are
needed. Given the immunogenic nature of S. pneumoniae proteins, these molecules
are being investigated as potential vaccine candidates. Pneumococcal surface
protein A (PspA) has been evaluated for its ability to elicit protection against
S. pneumoniae infection in mouse models of systemic and local disease. This
review focuses on immune system responsiveness to PspA and the ability of PspA to
elicit cross-protection against heterologous strains. These parameters will be
critical to the design of broadly protective pneumococcal vaccines.
PMID- 9767069
TI - Central pain and dysesthesia syndrome.
AB - This article presents recent observations about different recognized central pain
syndromes (CPS) and discusses them in light of contemporary microelectrode and
imaging findings. Different theories regarding the generation of CPS are
reviewed, with an emphasis on difficulties in diagnosis and treatment. The author
discourages destructive procedures for treatment of CPS, favoring, instead,
reversible procedures such as stimulation techniques and drug delivery systems.
PMID- 9767068
TI - Pain in central and peripheral demyelinating disorders.
AB - Moderate to severe pain is a common feature of central and peripheral
demyelinating disorders. Pain in multiple sclerosis tends to occur when the
disease is well-established and usually lingers infinitely. Pain in Guillain
Barre syndrome tends to be particularly severe at the time of initial
presentation and usually resolves over 8 to 12 weeks. Pain in both conditions is
generally caused by either the direct effects of nerve injury or the result of
paralysis and prolonged immobilization. Pain syndromes are well-defined in each
disorder based on the underlying pathophysiology. Treatment involves a variety of
pharmacologic and nonpharmacologic approaches individualized for each specific
pain syndrome.
PMID- 9767071
TI - New developments in rehabilitation of neuropathic pain syndromes.
AB - The common medical treatments of neuropathic pain, medication and nerve blocks,
are often only partially effective in providing significant and long-term pain
relief. Patients suffering chronic pain often fall prey to associated emotional
suffering, functional impairment, and difficulties in multiple areas of their
lives, including family disruption, social withdrawal, and vocational disability.
An interdisciplinary approach to pain management draws on the skills of physical
and occupational therapists, pain psychologists, biofeedback specialists, and
vocational counselors. It focuses on both pain management and functional
restoration, and should be considered standard treatment for chronically painful
conditions. Interdisciplinary pain management views the patient as an active
agent, responsible for learning and applying self-management techniques for
controlling pain, with the staff assuming a teaching and consulting role.
Although much more labor intensive, interdisciplinary pain management is more
effective over time in managing chronic pain, in preventing unnecessary emotional
and physical impairment, and in controlling overall medical costs.
PMID- 9767070
TI - Phantom limb pain and related disorders.
AB - Postamputation phenomena, including painful and nonpainful phantom sensations
occur following loss of limbs and other body parts. Peripheral and central
nervous system mechanisms play a role in persistent phantom pain. Understanding
the pathophysiology of this syndrome has improved in recent years. Comprehensive
evaluation and a multimodality treatment approach comprise the current standard
of care of the patient with phantom pain.
PMID- 9767072
TI - Recent advances in the pharmacology of nerve-injury pain.
AB - Nerve injury pain remains a complex clinical challenge. Although the development
of animal models of nerve injury pain has aided our understanding of potential
pathophysiologic mechanisms for this condition, effective treatment still remains
beyond our reach. Several classes of agents appear to block pain behavior in
these animal models and humans, but they are often limited in their use by low
efficacy, or undesirable side-effects. A prerequisite for the improvement of
nerve injury pain includes the development of clinically-relevant animal models
in which therapeutic targets can be identified.
PMID- 9767074
TI - Simultaneous analysis of multiple gene expression patterns as a function of
development, injury or senescence.
AB - Concurrent changes in expression of eight genes were examined following cryogenic
rat brain injury. Cortical RNA levels were catalogued at time 0, and at 1 h and 1
week following injury. The genes include thymidine kinase (TK), c-fos, renin,
myelin basic protein (MBP), proteolipid protein (PLP), glial fibrillary acidic
protein (GFAP), insulin-like growth factor-1 (IGF-1), and somatostatin. All
demonstrate increased expression following injury. Renin and c-fos exhibit
detectable changes as early as 1 h post-injury.
PMID- 9767073
TI - Oxidation of NADH by intact segments of soybean hypocotyls and stimulation by 2,4
D.
AB - Intact sections of soybean cut from regions of cell elongation of hypocotyls of
etiolated soybean seedlings oxidized externally supplied NADH (NADH is an
impermeant substrate). The oxidation of NADH by 1-cm intact sections was
stimulated by the plant growth factor 2,4-dichlorophenoxyacetic acid (2,4-D). The
optimum concentration of 2,4-D for stimulation was about 1 microM. Stimulations
also were given by the naturally occurring 2,4-D analog, indole-3-acetic acid
(IAA), but not by the growth inactive 2,4-D analog 2,3-dichlorophenoxyacetic acid
(2,3-D). The findings confirm studies comparing inside-out and right side-out
vesicles that show the 2,4-D-stimulated NADH oxidase to be located at the
external cell surface. Since plant cells are unlikely to encounter NADH at their
external cell surface, functions of the oxidase in reactions other than oxidation
of NADH are discussed.
PMID- 9767075
TI - Homeoboxes in plant development.
AB - The homeobox is a 180 bp consensus DNA sequence present in a number of genes
involved in developmental processes. This review focuses on the structure and
function of plant homeobox genes and of the proteins they encode. Plant homeobox
genes have been identified in studies using mutants, degenerate oligonucleotides
deduced from conserved sequences, differential screening or binding to known
promoters. According to sequence conservation, plant homeoboxes can be subdivided
into different families, each comprising several members. Evolutionary studies
indicate that the different families have diverged prior to the separation of the
branches leading to animals, plants and fungi. Accordingly, members of different
families show characteristic structural and functional properties. As an example,
kn1-like genes seem to be involved in different aspects of the control of cell
fate determination in the shoot meristem; HD-Zip genes, which encode proteins
containing a leucine zipper motif adjacent to the homeodomain, are believed to
operate at later stages of development; and gl2-like genes are involved in
epidermal cell differentiation. Future studies should be oriented to discern the
precise function of the many homeobox genes present in plant genomes, and to
evaluate their use as modifiers of plant development.
PMID- 9767076
TI - A new member of YER057c family in Trypanosoma cruzi is adjacent to an ABC
transporter.
AB - Tcp17 is a Trypanosoma cruzi gene located contiguous to the ABC-transporter
tcpgp2. The protein contains 160 amino acid residues with a predicted molecular
mass of 16.5kDa. Western blot analysis using a polyclonal antiserum against
recombinant TCP17 revealed that the protein is only expressed in the epimastigote
form of the parasite; we did not detect the protein either in the amastigote or
trypomastigote forms. A sequence comparison of TCP17 showed a remarkable homology
with a conserved family of prokaryotic and eukaryotic proteins called YER057c
whose function has not yet been characterized. Here, we propose a new signature
of this family considering the N-terminal: [IV]-X(4)-[AV]-[AP]-X-[AP]-X(3)-Y-X(9)
[LIVF]-X(2)-[SA]-G-[QS], and the C-terminal: [AT]-R-X(2)-[IVFY]-X-[VC]-X(2)-L-P
X(4)-[LIVM]-E-[IVM] -[DE] motifs. Immunofluorescence and immunoelectron
microscopy studies suggest that the protein has a wide distribution in the cell,
with a higher concentration in the external side of the plasma membrane, on the
Golgi complex and on cytoplasmic vacuoles. Although the physiological function of
TCP17 is unknown, its conservation in evolution suggests biological relevance in
the parasite.
PMID- 9767077
TI - Structure and expression of fatty acid desaturases.
AB - Fatty acid desaturases are enzymes that introduce double bonds into fatty acyl
chains. They are present in all groups of organisms, i.e., bacteria, fungi,
plants and animals, and play a key role in the maintenance of the proper
structure and functioning of biological membranes. The desaturases are
characterized by the presence of three conserved histidine tracks which are
presumed to compose the Fe-binding active centers of the enzymes. Recent findings
on the structure and expression of different types of fatty acid desaturase in
cyanobacteria, plants and animals are reviewed in this article. Roles of
individual desaturases in temperature acclimation and principles of regulation of
the desaturase genes are discussed.
PMID- 9767078
TI - Molecular regulators involved in vertebrate eye development.
AB - Development of the eye can be subdivided into three phases. The first phase is
the formation of the major structures of the eye by the processes of induction
and regional specification. The second is the maturation of these structures to
form the functional eye, and the third phase is the formation of neuronal
connections between retina and the optic tectum. These processes are tightly
regulated by signalling cascades that direct axonal outgrowth, cellular
proliferation and differentiation. Some members of these signalling cascades have
been identified in recent studies. These include secreted factors which transmit
signals extracellularly, and receptors and transcription factors which are
members of intracellular signalling pathways that respond to extracellular
signals. This review summarizes the recent research that has implicated these
factors in playing a role in eye development on the basis of functional or
expression criteria.
PMID- 9767079
TI - Effects of the loss of capacity for N-glycosylation on the transport activity and
cellular localization of the human reduced folate carrier.
AB - The role of N-glycosylation in reduced folate carrier (RFC) transport and
membrane targeting was examined in transport-deficient K562 (K500E) cells
transfected with human RFC cDNAs. Treatment of cells expressing wild-type RFC
with tunicamycin (0-3 microg) resulted in a progressive shift of the
approximately 85 kDa RFC on western blots to 65 kDa. At 3 microg/ml tunicamycin,
the nearly complete loss of glycosylated RFC was accompanied by a approximately
25% decreased rate of methotrexate uptake. A deglycosylated RFC cDNA construct in
which asparagine-58 was replaced by glutamine (Gln58-RFC) was expressed in K500E
cells as a 65 kDa protein and restored transport capacity for methotrexate and
(6S)5-formyl tetrahydrofolate. With both wild-type and Gln58-RFC constructs,
expression of cDNA-encoded RFC protein far exceeded relative levels of RFC
uptake. Wild-type and Gln58-RFCs containing a hemagglutinin (HA) epitope at the
carboxyl terminus were similarly functional and, by immunofluorescence staining
with rhodamine-conjugated anti-HA antibody, were localized to plasma membranes.
Collectively, our results demonstrate that N-glycosylation of human RFC plays no
significant role in either transport function or membrane targeting. The
discrepancy between the stoichiometries of RFC expression and transport activity
for both wild-type RFC and Gln58-RFC implies that identical regulatory controls
and/or non-RFC transport components are necessary to completely restore transport
function in the transfected cells.
PMID- 9767080
TI - Newborn rat brainstem preparation with the trigeminal nerve attached for pain
study.
AB - Studies using a brainstem-spinal cord preparation isolated from newborn rats have
provided substantial information on neuro-physiology, -pharmacology and -anatomy
of the respiratory center, such as mechanisms of respiratory rhythm generation,
development of a respiratory center or respiratory reflex [T. Murakoshi, T.
Suzue, S. Tamai, A pharmacological study on respiratory rhythm in the isolated
brainstem-spinal cord preparation from newborn rat, Br. J. Pharmac. 86 (1985) 95
104 [5]; H. Onimaru, A. Arata, I. Homma, Primary respiratory rhythm generator in
the medulla of brainstem-spinal cord preparations from newborn rats, Brain Res.
445 (1988) 314-324 [6]; H. Onimaru, I. Homma, Whole cell recordings from
respiratory neurons in the medulla of brainstem-spinal cord preparations isolated
from newborn rats, Pflugers Arch. 420 (1992) 399-406 [7]; J.C. Smith, K.
Ballanyi, D.W. Richter, Whole-cell patch clamp recordings from respiratory
neurons in neonatal rat brainstem in vitro, Neurosci. Lett. 314 (1992) 153-156
[10]; T. Suzue, Respiratory rhythm generation in the in vitro brainstem-spinal
cord preparation of the neonatal rat, J. Physiol. (London) 354 (1984) 173-183
[11], reviewed in H. Onimaru, A. Arata, I. Homma, Neuronal mechanisms of
respiratory rhythm generation: An approach using in vitro preparation, Jpn. J.
Physiol. 47 (1997) 385-403 [8]]. Recently, the dissecting method of the
preparation was modified to introduce a brainstem preparation with the trigeminal
primary afferents attached for pain studies [M. Hamba, Repetitive stimulation
potentiated the stimulus-evoked firing in the trigeminal caudalis-in vitro study.
Neurosci. Res. 20 (1996) s163 [2]; M. Hamba, Stimulation-induced responses of the
trigeminal caudal neurons in the brainstem preparation isolated from newborn
rats, Brain Res. 785 (1998) 66-74 [3]]. As reported previously [3], the activity
dependent change in the excitability of pain-processing neurons, wind-up
phenomenon, was studied in the trigeminal caudalis by stimulating the mandibular
nerve, using a modified brainstem preparation isolated from newborn rats. The
caudalis, the medulla dorsal horn, is known as the center for processing pain and
sensory information from the cranio-facial area. The results indicated that the
brainstem preparation is applicable for studies on the neuroplasticity at the
pain-processing synapses. Here, we describe the method for isolation of a
brainstem preparation with the trigeminal mandibular nerve attached and for
recording the synaptic response evoked in the caudal neurons, using a whole-cell
patch clamp technique. In the present study, we demonstrated repetitive
stimulation-induced responses of caudal neurons at postnatal day 1 as an example
showing the feasibility of the preparation for pain studies.
PMID- 9767081
TI - Determination of the depth of BODIPY probes in model membranes by parallax
analysis of fluorescence quenching.
AB - The location of a series of lipophilic and lipid-attached BODIPY (4, 4-difluoro-4
bora-3a,4a-diaza-s-indacene) membrane probes was analyzed by the quenching of
BODIPY fluorescence by a series of nitroxide-labeled lipids in which the depth of
the nitroxide group is varied. When attached to the polar headgroup of PE the
BODIPY remained near the polar headgroup in depth. However, when attached at the
end of free or phospholipid-attached fatty acyl chains, or when attached to two
hydrocarbon chains, we observed two probe populations. One, usually dominant,
population of BODIPY groups 'looped back' towards the surface, but a second
population remained deeply embedded within the bilayer. When attached to a fatty
acid or fatty acyl chain, the deep population appeared to locate at a depth
related to its point of attachment to the acyl chain. In BODIPY linked to free
fatty acids, the location of the deep population responded to the ionization of
the carboxyl group. Because, unlike NBD (7-nitro-2,1,3-benzoxadiazol-4-yl) and
most dansyl groups, acyl chain linked BODIPY groups can exist in a deeply buried
form we conclude that BODIPY linked acyl chains are superior to NBD or dansyl
linked acyl chains as membrane probes.
PMID- 9767082
TI - Characterization of the pectin methylesterase-like gene AtPME3: a new member of a
gene family comprising at least 12 genes in Arabidopsis thaliana.
AB - Pectin demethylesterification appears to be catalysed by a number of pectin
methylesterase (PME) isoenzymes in higher plant species. In order to better
define the biological role of these isoenzymes in plant cell growth and
differentiation, we undertook molecular studies on the PME-encoding genes in
Arabidopsis thaliana. In this paper, we report the characterization of AtPME3, a
new PME-related gene of 4kb in length that we have mapped on Chromosome III.
AtPME3 encodes a putative mature PME-related isoenzyme of 34kDa with a basic
isoelectric point. Since the extent of the gene family encoding PME in higher
plant species is still unknown, we resorted to the use of degenerate primers
designed from several well-known consensus regions to identify new PME-related
genes in the genome of Arabidopsis. Our results, in combination with several
known expressed sequences tags (ESTs), indicate that the Arabidopsis genome
contains at least 12 PME-related genes. Consequently, a method of systematic gene
expression analysis has been applied in order to discern the expression pattern
of these 12 genes throughout the plant at the floral stage. Whereas most of these
genes appeared to be more or less ubiquitously expressed throughout the plant,
several genes are distinguishable by their strikingly specific expression in
certain organs. The present data bring a new insight into the role of specific
PME-related genes in flower and root development.
PMID- 9767083
TI - Laser-Doppler flowmetry utilizing a thinned skull cranial window preparation and
automated stimulation.
AB - For several decades, cranial windows have been used to investigate questions
relating to cerebral blood flow and its regulation. In general, these techniques
have utilized either 'open' cranial windows for the direct observation of the
intracranial vasculature, or 'closed' cranial windows in which the skull and dura
are removed and replaced with a clear seal, such as a coverslip. Here we describe
a method of studying blood flow responses elicited by the physiological stimulus
of whisker movement while using a 'thinned skull' cranial window created over the
rat whisker-barrel cortex. This method employing an automated whisker stimulator
coupled with laser-Doppler flowmetry focused through the thinned skull cranial
window, is less invasive than other cranial window techniques, and allows for the
study of the effects of stimulation parameters and systemically administered
compounds on whisker movement elicited blood flow responses. Automated whisker
stimulation and data collection also allow for precise temporal averaging of
laser-Doppler measured responses, leading to increased precision in determining
the true shape of the evoked blood flow response pattern.
PMID- 9767084
TI - Distribution of 11-cis LRAT, 11-cis RD and 11-cis REH in bovine retinal pigment
epithelium membranes.
AB - Our recent finding of the co-localization of 11-cis retinyl esters and 11-cis
retinyl ester hydrolase (11-cis REH) activity in bovine retinal pigment
epithelium (RPE) plasma membrane (PM) has led us to explore the possibility that
the PM may provide 11-cis retinal for rhodopsin regeneration. In the RPE, visual
chromophore is synthesized via a membrane associated 11-cis retinol dehydrogenase
(11-cis RD). Accordingly, bovine RPE membranes enriched with either endoplasmic
reticulum (ER) or plasma membrane (PM) enzyme markers were prepared and assayed
for visual cycle enzyme activities. Pronounced 11-cis RD activity was associated
with both ER- and PM-enriched membrane fractions. In contrast, 11-cis REH
activity was mostly recovered in PM-enriched fractions while LRAT activity was
found only in ER-enriched membranes. The finding that both 11-cis retinol and 11
cis retinal can be produced at the PM of the bovine RPE strongly suggests that 11
cis retinyl esters at this subcellular locale serve as a precursor of visual
chromophore for pigment regeneration.
PMID- 9767085
TI - A constitutively activated mutant of galphaq down-regulates EP-cadherin
expression and decreases adhesion between ectodermal cells at gastrulation.
AB - We have examined the expression and function of the heterotrimeric GTP-binding
protein Gq during early Xenopus embryogenesis. Abundant XGalphaq transcripts were
detected in oocytes and early embryos by Northern blot analysis. In situ
hybridization revealed that these transcripts are confined to the animal
hemisphere of the mature oocyte and to the presumptive ectoderm of cleaving
embryos. Microinjection at the two-cell stage of alphaq and Q209Lalphaq, a
constitutively activated mutant, causes a disruption in ectodermal cell adhesion
at late gastrulation. Dissociation/reaggregation experiments performed on animal
cap explants clearly demonstrate that the Q209Lalphaq-induced phenotype occurs
after reaggregation of the explants with a time-course similar to that observed
in whole embryos. RT-PCR experiments performed on the explants from Q209Lalphaq
injected embryos revealed a selective decrease in the amount of EP-cadherin mRNA.
Co-injection of EP-cadherin RNA, but also E-cadherin RNA, rescued the
disaggregated phenotype. These data emphasize the functional link between Gq
protein-coupled signalling pathways and cadherin molecules in the ectodermal
layer during the morphogenetic movements of gastrulation.
PMID- 9767086
TI - Treatment with anti-transforming growth factor beta antibodies influences an
altered pattern of cytokines gene expression in injured rat liver.
AB - The role of transforming growth factor beta1 (TGF-beta1) in mediating hepatic
inflammation and regeneration after acute liver injury is beginning to be
elucidated, yet its in vivo effect on the gene expression of the major pro
inflammatory and anti-inflammatory cytokines produced during that process is
unknown. Our previous experiments demonstrated that anti-TGF-beta-treated animals
presented profound histological changes as compared with control animals.
Therefore, our hypothesis was that by blocking in vivo TGF-beta1 action, with
polyclonal anti-TGF-beta antibodies, we could monitor by RT-PCR significative
alterations on the gene expression of IL-1beta, IL-6, TGF-beta, TNF-alpha, IL-4
and IL-10 in liver-regenerated rats after administration of a single CCl4 dosing.
Accordingly, we here report a completely different pattern of cytokines gene
expression amidst those groups of rats. Pro-inflammatory cytokines gene
expression in control animals showed a clear-cut pattern peaking at 1-2 days
postinjury and declining thereafter. Interestingly, IL-6 was present in the
control animals only between 12 and 24 h after CCl4 dosing. In the experimental
animals, TGF-beta1 was mainly increased at 4 and 6 days, while IL-6 mRNA was
completely absent. IL-1beta mRNA expression was also altered in the experimental
rats, albeit TNF-alpha was nearly unaffected. IL-4 was fully absent in control
rats, but remarkably expressed in experimental animals throughout the study. IL
10 was also more expressed in experimental animals.
PMID- 9767087
TI - Neisseria gonorrhoeae contains multiple copies of a gene that may encode a site
specific recombinase and is associated with DNA rearrangements.
AB - A 960-bp ORF potentially encoding a site-specific recombinase has been cloned
from Neisseria gonorrhoeae MS11-A. This ORF was designated pivNg on the basis of
similarity of the deduced amino acid sequence to the Piv proteins of Moraxella
spp. that are site-specific invertases. Southern hybridization and sequence
analysis revealed that there were multiple copies of pivNg sequence within the
genomes of N. gonorrhoeae strains tested, but not in several other neisserial
species. Southern hybridization and sequence analysis further suggested that
pivNg sequences may be associated with genomic rearrangements.
PMID- 9767088
TI - Simultaneous isotopic and nonisotopic in situ hybridization histochemistry with
cRNA probes.
AB - In situ hybridization histochemistry is widely used to study gene expression at
the mRNA level in tissues and cells. Double label in situ hybridization allows
for coexpression studies. We describe a protocol for the simultaneous
hybridization of two cRNA probes tagged with and digoxigenin-UTP, respectively,
to frozen brain tissue sections. Hybridization signals of digoxigenin-tagged
probes appear as purple cytoplasmic staining following detection of digoxigenin
residues by an alkaline-phosphatase-(AP)-linked antibody. Signals resulting from
hybridization of radiolabeled probes are detected as silver grains overlying
cellular profiles in sections coated with autoradiographic emulsion. Grain
counting allows for semiquantitatively estimates of the cellular expression
levels of transcripts. Suitable cRNA-probes can be derived from linear templates
generated by polymerase chain reaction (PCR) using nested primers which contain
RNA-polymerase promotor sites. The cRNA-probes are sensitive and allow an
application of this protocol to the detection of a wide range of mRNAs of medium
or low abundance.
PMID- 9767089
TI - Incorporation of extracellular phospholipids and their effect on the growth and
lipid metabolism of the Saccharomyces cerevisiae cho1/pss mutant.
AB - The cho1/pss mutant of Saccharomyces cerevisiae, which is auxotrophic for choline
or ethanolamine because of the deficiency in phosphatidylserine synthesis, grew
in the presence of 0.05 mM phosphatidylcholine (PC) with octanoic acids (diC8PC)
or decanoic acids (diC10PC), but not in the presence of PC with longer acyl
residues. It did not grow in the presence of the soluble hydrolytic products of
PC, phosphorylcholine or glycerophosphorylcholine, at comparable concentrations.
Addition of 10 mM hemicholinium-3, a choline transport inhibitor, or disruption
of the CTR gene, which encodes a choline transporter, inhibited the growth of the
cho1/pss mutant in the presence of choline, but not in the presence of 0.1 mM
diC8PC. Under diC8PC-supported growth conditions, octanoic acid was barely
detectable in the cellular phospholipid fraction, but was recovered in the
culture medium as the free acid, and the phosphatidylethanolamine (PE) content
was low in comparison to the choline-supported conditions. These results suggest
that PCs with short acyl residues were taken up by the cho1/pss mutant and
remodeled as they were used, and that PCs with short acyl residues do not inhibit
conversion of PE to PC. The current results provide a new direction in the
analysis of intracellular phospholipid movement and metabolism in yeast.
PMID- 9767090
TI - Ultrastructural characterization of cationic liposome-DNA complexes showing
enhanced stability in serum and high transfection activity in vivo.
AB - We have investigated the morphology and transfection activity of cationic
liposome-DNA complexes (CLDC) under conditions relevant to both in vivo and in
vitro studies. Moreover we have attempted to establish structure-function
relationships relevant for high transfection activities under both conditions.
CLDC were composed of dimethyldioctadecylammonium bromide with either 1, 2
dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) or cholesterol (Chol)
interacting either with pre-condensed DNA or with uncondensed plasmid DNA.
Furthermore for steric stabilization 1% poly(ethylene glycol)-phospholipid
conjugate was added to CLDC containing Chol and plasmid DNA. The in vivo studies
were carried out in mice following i.v. injection, and the in vitro studies were
performed on SK-BR-3 human breast cancer cells in the presence of media with
serum. The morphology of the CLDC, monitored by freeze-fracture electron
microscopy, was investigated after mixing with mouse serum or the medium where
the cells were kept. The substitution of DOPE with Chol, and the addition of N
[omega-methoxypoly(oxyethylene)-alpha-oxycarbonyl-DSPE+ ++ are producing CLDC
which are stabilized with respect to time and serum, and are relatively small
(100-300 nm). These stabilized complexes show high expression of a marker gene in
mouse lungs reaching expression values up to 10 ng luciferase per mg tissue
protein, but relatively low expression in SK-BR-3 cells in vitro. Additionally,
some of the complexes containing pre-condensed DNA look like 'map-pin' structures
showing heads of the size of liposomes and short, stiff and tapering tails. The
in vivo transfection activity of these preparations is highest. Similar complexes
containing DOPE rather than Chol as helper lipid precipitate in the presence of
serum and especially of cell medium and convert into hexagonal lipid (HII) phase.
Such complexes, despite their high transfection activity in vitro, show very
little transfection activity in vivo. These comparisons may help us to understand
the fundamental difference between in vitro and in vivo activity of CLDC: high in
vitro transfection activity seems to be associated with hexagonal lipid
precipitates whereas high in vivo activity seems to be related with small,
stabilized complexes, which in our case also exhibit some protrusions (map-pin
structures).
PMID- 9767091
TI - Herpesvirus thymidine kinase transgenes that do not cause male sterility are
aberrantly transcribed and translated in the testis.
AB - Mice that carry the wild-type herpes simplex virus type 1 (HSV1) thymidine kinase
(tk) gene coupled to the bovine thyroglobulin (bTG) promoter (bTG-tk1 mice)
express viral TK at a high level in the thyroid gland, and at an equally high
level, ectopically, in the testis, which renders the males sterile. When the bTG
promoter was coupled either to a variant of HSV1-tk (differing from the wild type
in 2 nucleotides) (bTG-tk1alpha mice) or to the herpes simplex virus type 2
(HSV2) tk gene (bTG-tk2 mice) viral TK was expressed at high levels in the
thyroid gland, and much lower levels in the testis, which causes a reduction in
male fecundity rather than sterility. Here, we compare the expression of the
three transgenes in the two tissues. Thyroids of all mice exhibited a 1.3 kb RNA
initiated at or near the bTG cap site. Testes of all mice exhibited mainly 5'-end
shortened RNAs (bTG-tk1 and bTG-tk1alpha mice, approx. 1.2 kb and 0.9 kb; bTG-tk2
mice, approx. 1.2 kb) initiated from cryptic initiation sites in the HSV1-tk and
HSV2-tk coding regions. Also, less abundant RNAs initiated near the bTG cap site
were expressed from all three transgenes. Thyroids of bTG-tk1 and bTG-tk1alpha
mice contained the full-length HSV-TK protein and a truncated variant previously
shown to originate at a non-ATG start codon. Testes of these mice exhibited both
proteins but relatively less of the full-length protein. We attribute the high
level of viral TK in the testes of bTG-tk1 mice to the expression of a
predominant protein of Mr 39000 that originates from ATG-2. Thyroid and testis of
bTG-tk2 mice contained only the full-length HSV2-TK protein.
PMID- 9767092
TI - Cloning and expression of the Zymomonas mobilis pyruvate kinase gene in
Escherichia coli.
AB - The homotetrameric pyruvate kinases (PK) constitute a fine example of allosteric
enzymes subjected to sophisticated regulatory mechanisms. We have cloned and
sequenced the Zymomonas mobilis structural gene for the first prokaryotic dimeric
PK, as an initial step toward understanding the peculiar properties of this
enzyme. The deduced amino acid sequence of the pyk gene consists of 475 residues
with a calculated molecular mass of 51.4kDa and exhibits up to 50% sequence
identity with other PKs. Heterologous expression in Escherichia coli was not
obtained from the native promoter, but only when the pyk gene was under the
control of a strong inducible promoter when a ribosome-binding site was present
upstream of the putative TTG start codon of the pyk gene. Kinetic
characterization of PK in concentrated crude cell extracts showed that the enzyme
is not activated by sugar phosphates or AMP but is slightly inhibited by ATP.
Thus, PK of Z. mobilis is unique among the characterized prokaryotic PKs due to
its high activity in the absence of any allosteric activator. Amino acid sequence
alignments revealed that glutamate 381 may play a role in ineffective binding of
the usual PK activator, fructose-1,6-bisphosphate.
PMID- 9767093
TI - Stimulation of monocytes and platelets by short-chain phosphatidylcholines with
and without terminal carboxyl group.
AB - Oxidation of unsaturated phosphatidylcholine (PC) produces fragmented
phospholipids which have similar bioactivities as the platelet-activating factor
(PAF, 1-O-alkyl-2-acetyl-PC). Since a large number of molecular species are
produced upon PC oxidation, the active ingredients have not been identified. We
synthesized several short-chain PCs which are known to be characteristic PC
oxidation products to test their PAF-like activity. The synthetic PCs contained
palmitoyl or hexadecyl residues (both C16) in sn-1 position, and propionyl (C3),
valeroyl (C5), succinyl (C4 with omega-carboxyl), glutaroyl (C5 with omega
carboxyl), or suberoyl (C8 with omega-carboxyl) residues in sn-2 position.
Biological activity was measured by: (1) increase of intracellular calcium in
human monocytes; (2) [3H]serotonin release from rabbit platelets; and (3)
aggregation of human platelets. Specificity of the cellular response was tested
by inhibition with the PAF-receptor antagonists BN 52021 and WEB 2086. Synthetic
PC oxidation products activated both monocytes and platelets in a PAF-specific
manner. The effective concentration varied with respect to assay system and
chemical structure. In general, 1-hexadecyl-PCs were more effective than 1
palmitoyl-PCs, while increasing chain length in sn-2 position lowered biological
activity. However, several 1-palmitoyl-PCs activated monocytes in concentrations
between 10-8 and 10-6 M. In contrast, platelets were less susceptible to 1
palmitoyl-PCs. No significant difference was found between 2-valeroyl-PC (C5 with
omega-methyl) and 2-glutaroyl-PC (C5 with omega-carboxyl). The data suggest that
typical products of PC oxidation, containing propionyl, succinyl, or glutaroyl
residues in sn-2 position, display PAF-like activity at micromolar
concentrations.
PMID- 9767094
TI - Dynamic developmental expression of smallminded, a Drosophila gene required for
cell division.
AB - Here we describe the expression pattern of the smallminded (smid) gene during
Drosophila development and investigate the phenotype of a null mutant. In situ
hybridisation reveals the ubiquitous expression of smid transcript throughout
early embryonic stages until the extended germ band stage, after which expression
becomes localised to the neurogenic ectoderm and gonad. Post-embryonic expression
is restricted to tissues engaged in the developmental programme of the adult fly:
the re-enlarged neuroblasts; imaginal disks; histoblast nests; and precursors of
adult muscles. The correlation of smid expression with mitotic activity suggests
a cell cycle function which is confirmed by the observed phenotype of a smid null
mutant characterised by an abnormally small CNS, due to defective mitosis of post
embryonic neuroblasts and their subsequent death by apoptosis.
PMID- 9767095
TI - Measurement of the extracellular H2O2 in the brain by microdialysis.
AB - This paper reports on the protocol for the determination of H2O2 in the brain
using in vivo microdialysis coupled with fluorometry of dichlorofluorescin
oxidation. We applied this protocol to monitor changes in the concentration of
H2O2 in the brain, in vivo, during ischemia and reperfusion. Using this method,
changes in the level of H2O2 in the brain during ischemia and reperfusion were
effectively determined. The present protocol provides a novel tool to study the
production of reactive oxygen species in the brain.
PMID- 9767096
TI - Fructans interact strongly with model membranes.
AB - Bacterial fructans with a high degree of polymerisation cause a very large
increase in surface pressure of lipid monolayers at the air-water interface with
a broad range of lipids, including phosphatidylethanolamine and several types of
phosphatidylcholines. The surface active effect of fructans contrasts strongly
with the maximal effects observed for trehalose, sucrose and glucose under
comparable conditions (20 and 0.6 mN/m for fructans and the other sugars,
respectively). The results demonstrate a profound and specific membrane
interaction of the fructans which is probably very different from the effect of
the smaller carbohydrates. The fructan concentrations used in this study are
within the physiological range observed in fructan-accumulating plants. The
suggested water-stress protective effect of fructans may be induced by membrane
fructan interaction which prevent lipid condensation and phase transitions to
take place.
PMID- 9767097
TI - An in vitro technique for tracing neuronal connections in the teleost brain.
AB - The availability of neuronal tract-tracing techniques has been fundamental to the
development of the neurosciences. While most of the previously described methods
are performed in vivo, in the present paper, detailed protocols are reported for
tracing neuronal connections in an in vitro preparation. This technique, tested
in various neural systems of the teleost brain, allows precise application of
tracer substance(s) under visual control. After the isolation of the brain, the
tissue is kept alive by superfusion with oxygenated artificial cerebrospinal
fluid in a slice chamber. Neuronal connections are traced by the application of
crystals of biocytin or dextran-tetramethylrhodamine to the region of interest.
Following intracellular transport over 8-18 h, the tissue is fixed and processed
histochemically for visualization of structures filled with the tracer substance.
This method can readily be modified for double labelling. Step-by-step procedures
are outlined for (a) the simultaneous detection of two tracer substances in the
same tissue sample, (b) the combination of tract tracing with the
immunohistochemical identification of various biochemical markers such as
'classical' transmitters and neuropeptides, and (c) the visualization of both
traced structures and mitotically active cells labelled with the thymidine
analogue 5-bromo-2'-deoxyuridine. By exhibiting a high degree of efficiency, the
described in vitro tract-tracing technique represents also a significant
contribution towards a reduction of living animals in neurobiological
experimentation.
PMID- 9767098
TI - Role of adenine nucleotides, molecular chaperones and chaperonins in
stabilization of DnaA initiator protein of Escherichia coli.
AB - DnaA protein of Escherichia coli is a sequence-specific DNA binding protein
required for the initiation of DNA replication from the chromosomal origin, oriC,
and of several E. coli plasmids. At a moderate ionic strength, purified DnaA
protein has a strong tendency to aggregate; the self-aggregate form is inactive
in DNA replication. Binding of ATP or ADP to DnaA protein protected it from
aggregation to maintain its replication activity. AMP or cyclic AMP had no
protective effect. The molecular chaperone DnaK protected DnaA protein from
aggregation with or without ATP. DnaJ and GrpE were not stimulatory. Chaperonins
GroEL and GroES were also able to prevent aggregation but only in the presence of
ATP. The studies presented here show that for DnaA protein to be active in the
initiation of DNA replication, it must be prevented from forming a self-aggregate
by the binding of adenine nucleotides, and/or by the action of molecular
chaperones.
PMID- 9767099
TI - A novel spliced transcript of human CLAPS2 encoding a protein alternative to
clathrin adaptor protein AP17.
AB - Transcripts of genes encoding proteins of clathrin complexes have been reported
to undergo tissue-specific alternative splicing. AP17, encoded by human CLAPS2
cDNA, is the small chain of the major clathrin adaptor complex AP-2 associated
with mammalian plasma membranes. In this study, two cDNAs were isolated from a
cDNA library of human blood cells. Whereas one cDNA encoded AP17, the other cDNA
encoded a putative novel protein variant, termed AP17Delta. Both coding regions
were completely sequenced. Consisting of 142aa residues, the predicted protein
AP17Delta of 12kDa lacks 38aa residues of AP17. Using specific primers for RT
PCR, mRNAs for AP17Delta and AP17 were found in leukocytes and cultured leukemia
cells. The finding of a putative intron in a human EST cDNA clone suggests that
mRNAs for AP17 and AP17Delta are formed by alternative splicing. In addition, the
identity of human and rat AP17 amino acid sequences is demonstrated.
PMID- 9767100
TI - On the role of sterol in the formation of the amphotericin B channel.
AB - Amphotericin B is an antimycotic agent that has been studied for a long time,
both because of its pharmacological action and the interest in understanding how
this ionic channel works. It has been proposed that the channel is formed by a
barrel of monomers, and that the presence of sterol is needed for the formation
of such a barrel. As a matter of fact this need of a sterol has been used as a
guiding idea in attempts to design derivatives more efficient in the
discrimination of the cholesterol containing membranes, as compared to the
ergosterol containing ones, henceforth diminishing the unwanted side effects in
its pharmacological use. In this work we show that unitary channels that appear
in a cholesterol containing membrane also appear when this membrane is free of
cholesterol. We prove this to be the case for two membranes, a biological one,
asolectin, and a synthetic one, DMPC. We then advance the idea that the role of
sterols in the formation of the amphotericin B channel is related to the effects
they have on the structure of the membrane itself, rather than to a direct
involvement in the channel formation. We further look into the effect that
different cholesterol concentrations in the membrane produce on the single
channel properties.
PMID- 9767101
TI - Natural forms of shed tumor gangliosides.
AB - Gangliosides shed by tumor cells are immunosuppressive molecules, but the
mechanisms of shedding are poorly understood. We therefore conducted a
comprehensive study of shedding to identify the natural forms of shed
gangliosides. By chemical detection and mass spectrometric analysis of the
gangliosides of YAC-1 murine lymphoma cells, we first confirmed that all major
ganglioside species are released. Then, by the combination of metabolic and cell
surface radiolabeling, we further demonstrated that gangliosides are released
directly from the cell plasma membrane, i.e. by shedding. Ultracentrifugation
separated the conditioned medium of metabolically radiolabeled cells cultured in
either serum-free or serum-containing medium into: (1) a pellet of 100-200 nm
membrane vesicles (visualized by electron microscopy) containing nearly one-third
of total shed gangliosides; and (2) the supernatant, which contained soluble
gangliosides (two-thirds of the total shed gangliosides). Although the
ganglioside concentration in the conditioned medium (6-14x10-8 M) was above the
critical micelle concentration of purified YAC-1 gangliosides (<1x10-8 M), by gel
filtration >90% of the soluble gangliosides were found in monomeric form (MW <2
kDa) and only <10% in micelles (130 kDa). Ultrafiltration of fresh conditioned
medium likewise showed the existence of monomers, and the findings were confirmed
in human Daoy medulloblastoma and mouse MEB4 melanoma cells. Thus, in their
natural states, shed tumor cell gangliosides exist in three forms: membrane
vesicles, micelles, and monomers.
PMID- 9767102
TI - The Drosophila putative kinase linotte (derailed) prevents central brain axons
from converging on a newly described interhemispheric ring.
AB - The lio gene encodes a putative receptor tyrosine kinase, with unique motifs both
in the extracellular and catalytic domains (Dura, J.-M., Preat, T., Tully, T.,
1993. Identification of linotte, a new gene affecting learning and memory in
Drosophila melanogaster. J. Neurogenet. 9, 1-14). We show here that a complete
deletion of lio activity causes specific structural defects in the adult brain.
Gal4 enhancer-trap lines used as cell markers revealed that in lio mutants
central brain axons behave as if they were abnormally attracted by the midbrain
area. The Lio protein is expressed in third instar larvae in a few cells at the
junction of the cerebral hemispheres. These glial cells form a newly described
ring structure, showing an invariable fibrous organization. In the wild-type this
ring disappears at midpupation. Our results indicate that the Lio putative kinase
plays a major role in the modeling of the adult brain by controlling the fate of
the transient interhemispheric ring.
PMID- 9767103
TI - Molecular analysis of the split cox1 gene from the Basidiomycota Agrocybe
aegerita: relationship of its introns with homologous Ascomycota introns and
divergence levels from common ancestral copies.
AB - The Basidiomycota Agrocybe aegerita (Aa) mitochondrial cox1 gene (6790
nucleotides), encoding a protein of 527aa (58377Da), is split by four large
subgroup IB introns possessing site-specific endonucleases assumed to be involved
in intron mobility. When compared to other fungal COX1 proteins, the Aa protein
is closely related to the COX1 one of the Basidiomycota Schizophyllum commune
(Sc). This clade reveals a relationship with the studied Ascomycota ones, with
the exception of Schizosaccharomyces pombe (Sp) which ranges in an out-group
position compared with both higher fungi divisions. When comparison is extended
to other kingdoms, fungal COX1 sequences are found to be more related to algae
and plant ones (more than 57.5% aa similarity) than to animal sequences (53.6% aa
similarity), contrasting with the previously established close relationship
between fungi and animals, based on comparisons of nuclear genes. The four Aa
cox1 introns are homologous to Ascomycota or algae cox1 introns sharing the same
location within the exonic sequences. The percentages of identity of the intronic
nucleotide sequences suggest a possible acquisition by lateral transfers of
ancestral copies or of their derived sequences. These identities extend over the
whole intronic sequences, arguing in favor of a transfer of the complete intron
rather than a transfer limited to the encoded ORF. The intron i4 shares 74% of
identity, at the nucleotidic level, with the Podospora anserina (Pa) intron i14,
and up to 90.5% of aa similarity between the encoded proteins, i.e. the highest
values reported to date between introns of two phylogenetically distant species.
This low divergence argues for a recent lateral transfer between the two species.
On the contrary, the low sequence identities (below 36%) observed between Aa i1
and the homologous Sp i1 or Prototheca wickeramii (Pw) i1 suggest a long
evolution time after the separation of these sequences. The introns i2 and i3
possessed intermediate percentages of identity with their homologous Ascomycota
introns. This is the first report of the complete nucleotide sequence and
molecular organization of a mitochondrial cox1 gene of any member of the
Basidiomycota division.
PMID- 9767104
TI - cDNA cloning and Escherichia coli expression of UK114 tumor antigen.
AB - Experimental evidence indicates that the antineoplastic effects of UK101, a goat
liver perchloric acid extract, is likely due to one of its constituent proteins:
the 14 kDa protein named UK114. The cDNA encoding UK114, obtained by PCR
methodologies, contains an open reading frame coding for a protein of 137 amino
acids with a theoretical molecular mass of 14298 Da. It shows high sequence
homology with a 14 kDa protein identified in human, rat and Mus musculus tissues
which is likely involved in the inhibition of cell-free protein synthesis.
Northern blot analysis indicated that the transcript is present in variable
amounts in a wide range of human tissues. Genomic Southern blots revealed that
the UK114 mRNA in goat as well as in human is encoded by a single gene, as is the
case in rat. The expression system for UK114 was constructed under the control of
the PL promoter from bacteriophage lambda and the cDNA coding region has been
highly expressed in Escherichia coli as a thioredoxin fusion protein. The
recombinant UK114, purified to homogeneity, is immunoreactive to rabbit antisera
prepared against UK101 or native UK114, as well as to sera of UK101-treated
cancer patients. It inhibits cell-free protein synthesis at 8 microM
concentration.
PMID- 9767105
TI - Ionic channels formed by a primary amphipathic peptide containing a signal
peptide and a nuclear localization sequence.
AB - The peptide SP-NLS (Ac-Met-Gly-Leu-Gly-Leu-His-Leu-Leu-Leu-Ala10-Ala-Ala-Leu-Gln
Gly- Ala -Lys-Lys-Lys-Arg20-Lys-Val-NH-CH2-CH2-SH) is composed of a hydrophobic
signal sequence (SP, Met-1 to Ala-16) followed by a polycationic nuclear
localization sequence (NLS, Lys-17 to Val-22) terminated by a cysteamide group.
Designed to act as drug carrier this primary amphipathic peptide proved cytotoxic
and bactericidal when used at high concentrations, probably by inducing the
formation of ion channels. In this work, we show that indeed SP-NLS exhibits a
pore-forming activity when incorporated into planar lipid bilayers and Xenopus
laevis oocyte plasma membranes, with conductance values of 25 pS in 0.1 M NaCl.
In both membranes, the insertion of the peptide was voltage-triggered whereas the
induced conductances proved almost voltage-independent. Moreover, SP-NLS ion
channels were selective for monovalent cations
(K+>Na+>Li+>tetraethylammonium+>choline+). The ion channel activity of this type
of peptides thus provides some insight on their toxicity but also on the
mechanism involved for their membrane crossing process.
PMID- 9767106
TI - TUNEL, Hoechst and immunohistochemistry triple-labelling: an improved method for
detection of apoptosis in tissue sections--an update.
AB - We describe an updated protocol which allows the combination of the previously
described TUNEL and Hoechst 33342 double-labelling (G. Whiteside, N. Cougnon,
S.P. Hunt, R. Munglani, An improved method for the detection of apoptosis in
tissue sections and cell culture, using the TUNEL technique combined with Hoechst
stain, Brain Res. Protocols, 2, 1998, 160-164 [3]), with immunohistochemistry.
The inclusion of the immunohistochemistry step allows identification of apoptosis
in distinct cell types by using cell specific markers. It also permits
investigation into the proteins expressed in cells undergoing apoptotic cell
death. We have evaluated the triple staining in sections of post-axotomy neonatal
dorsal root ganglia.
PMID- 9767107
TI - lacZ transgenic mice to monitor gene expression in embryo and adult.
AB - In transgenic experiments, lacZ can be used as a reporter gene for activity of a
given promoter. Its main advantage is the ease of visualization in situ, on
sections or in whole mount preparations, and the availability of simple
protocols. In the following, we describe our procedure for detecting promoter
activity in transgenic mice, including choice of lacZ vectors, generation of the
transgenic mice, and analysis of expression. We had recently used this protocol
to detect tyrosinase gene promoter activity in embryonic and adult brain.
PMID- 9767108
TI - Comparison of sequences of a transcriptional coactivator MBF2 from three
Lepidopteran species Bombyx mori, Bombyx mandarina and Samia cynthia.
AB - MBF2 was first isolated from the silkworm Bombyx mori as a positive cofactor that
activates transcription through its interaction with TFIIA. To identify conserved
domain(s) within the MBF2 molecule, we isolated cDNAs encoding MBF2 homologues
from other silkworms Bombyx mandarina and Samia cynthia. Bacterially expressed
and purified MBF2 of B. mandarina and S. cynthia activated transcription in
vitro. The predicted amino acid sequences of MBF2 from two Bombyx species share
97% homology. When we compared between B. mori and S. cynthia factors, the
homology reduced to 50%. Four regions in MBF2 are conserved among these three
species. Two of them are present in the middle region of MBF2 that is essential
for the transcriptional activation.
PMID- 9767110
TI - Expression and characterization of human group V phospholipase A2.
AB - Group V phospholipase A2 (GV-PLA2) has been shown to be involved in signal
transduction and inflammatory processes in cellular studies, but the physical and
biochemical properties of this important enzyme have been unclear. We report the
over-expression and characterization of GV-PLA2. The GV-PLA2 cDNA was synthesized
from human heart polyA+ mRNA by RT-PCR, and an expression construct containing
the GV-PLA2 was established. After expression in Escherichia coli cells, the
protein was solubilized and purified to homogeneity in a single step using nickel
affinity chromatography. The purified GV-PLA2 protein was folded to form active
enzyme. The recombinant GV-PLA2 has an absolute requirement for Ca2+ for
enzymatic activity. The optimum pH for this enzyme is pH 8.5 in Tris-HCl buffer
with sonicated vesicles as substrate. GV-PLA2 preferentially hydrolyzes
phosphatidylethanolamine (PE) vesicles compared to phosphatidylcholine (PC)
vesicles. However, hydrolysis of PC and PE is equivalent in mixed vesicles of the
phospholipids. The fatty acid preference of GV-PLA2 is
linoleoyl>palmitoyl>arachidonyl with a PC head group and sonicated vesicles. 3-(3
Actamide-1-benzyl-2-ethylindolyl-5-oxy)propane phosphonic acid (LY311727), a
potent inhibitor of human group IIA PLA2, strongly inhibits GV-PLA2 with an IC50
value of about 36 nM which is comparable to its inhibition of group IIA PLA2.
PMID- 9767109
TI - High mobility group 1 (HMG1) protein in mouse preimplantation embryos.
AB - High mobility group 1 protein (HMG1) has traditionally been considered a
structural component of chromatin, possibly similar in function to histone H1. In
fact, at the onset of Xenopus and Drosophila development, HMG1 appears to
substitute for histone H1: HMG1 is abundant when histone H1 is absent after the
midblastula transition histone H1 largely replaces HMG1. We show that in early
mouse embryos the expression patterns of HMG1 and histone H1 are not
complementary. Instead, HMG1 content increases after zygotic genome activation at
the same time as histone H1. HMG1 does not remain associated to mitotic
chromosomes either in embryos or somatic cells. These results argue against a
shared structural role for HMG1 and histone H1 in mammalian chromatin.
PMID- 9767111
TI - Insulin inhibits surfactant protein A and B gene expression in the H441 cell
line.
AB - Fetuses of mothers with uncontrolled gestational diabetes have an increased risk
of developing neonatal respiratory distress syndrome and are frequently
hyperinsulinemic, thus it has been proposed that high levels of insulin delay
fetal lung maturation. We have shown previously that insulin inhibits the
accumulation of mRNA for the surfactant-associated proteins A and B (SP-A and SP
B) in human fetal lung explants maintained in vitro. To test the hypothesis that
the inhibitory effects of insulin on the surfactant proteins are the result of a
direct action of insulin on the lung epithelial cell, we evaluated the effects of
insulin in the H441 cell line, a human pulmonary adenocarcinoma cell line that
expresses SP-A and SP-B mRNA. We observed that insulin treatment for 48 h
decreased SP-A mRNA and protein levels in a concentration-dependent manner when
compared to controls. The inhibitory effect of insulin on SP-A mRNA levels was
apparent as early as after 4 h of exposure. SP-B mRNA levels were also
significantly decreased by insulin in a concentration-dependent manner. Insulin,
at 2.5 microg/ml, inhibited SP-A gene transcription by approx. 67%, and inhibited
SP-B gene transcription by about 32%. There was no significant effect of insulin
on SP-A or SP-B mRNA stability. Thus, we have observed a pattern of insulin
inhibition of SP-A and SP-B gene expression in the H441 lung epithelial cell line
similar to that previously observed in human fetal lung explants, which are
comprised of both epithelial and mesenchymal cells. Our findings provide further
evidence that insulin may delay fetal lung maturation by inhibiting SP-A and SP-B
gene expression. Furthermore, our findings suggest that the inhibitory effects of
insulin are, at least partially, the result of a direct action on the lung
epithelial cell.
PMID- 9767112
TI - Characterization of ATP and P2 agonists binding to the cardiac plasma membrane
P1,P4-diadenosine 5'-tetraphosphate receptor.
AB - P1,P4-Diadenosine 5'-tetraphosphate (Ap4A) acts as an extracellular modulator
through its interaction with purinoceptors. Our laboratory has demonstrated the
presence of an Ap4A receptor in cardiac tissue [1,2]. Due to the rapid hydrolysis
of ATP by cardiac membranes the relationship of ATP and Ap4A binding to
purinoceptors on cardiac membranes has not been characterized. In this
communication we used two approaches to determine the relationship of ATP to the
Ap4A receptor. Radioligand binding carried out with [alpha-32P]Ap4A and adenosine
5'-O-?3-thiotriphosphate? ([gamma-35S]ATPgammaS) demonstrates the presence of a
single high affinity binding site for Ap4A and the presence of two binding sites
for ATPgammaS. The second approach utilized immunoaffinity purified Ap4A receptor
that was shown to be free of ATPase and Ap4Aase activities. Non-radiolabeled Ap4A
and ATPgammaS effectively inhibited photocrosslinking of [alpha-32P]8-N3Ap4A to
the receptor polypeptide while ATP was a much less effective inhibitor.
Furthermore, on plasma membranes [alpha-32P]8-N3Ap4A photocrosslinked to only a
50 kDa polypeptide. These data are consistent with Ap4A interacting with a
homogeneous population of receptors on cardiac plasma membranes but with ATP
having a low affinity for the receptor.
PMID- 9767113
TI - Genomic organization of four beta-1,4-endoglucanase genes in plant-parasitic cyst
nematodes and its evolutionary implications.
AB - The genomic organization of genes encoding beta-1,4-endoglucanases (cellulases)
from the plant-parasitic cyst nematodes Heterodera glycines and Globodera
rostochiensis (HG-eng1, Hg-eng2, GR-eng1, and GR-eng2) was investigated. HG-eng1
and GR-eng1 both contained eight introns and structural domains of 2151 and
2492bp, respectively. HG-eng2 and GR-eng2 both contained seven introns and
structural domains of 2324 and 2388bp, respectively. No significant similarity in
intron sequence or size was observed between HG-eng1 and HG-eng2, whereas the
opposite was true between GR-eng1 and GR-eng2. Intron positions among all four
cyst nematode cellulase genes were conserved identically in relation to the
predicted amino acid sequence. HG-eng1, GR-eng1, and GR-eng2 had several introns
demarcated by 5'-GCellipsisAG-3' in the splice sites, and all four nematode
cellulase genes had the polyadenylation and cleavage signal sequence 5'-GAUAAA-3'
both rare occurences in eukaryotic genes. The 5'- flanking regions of each
nematode cellulase gene, however, had signature sequences typical of eukaryotic
promoter regions, including a TATA box, bHLH-type binding sites, and putative
silencer, repressor, and enhancer elements. Database searches and subsequent
phylogenetic comparison of the catalytic domain of the nematode cellulases placed
the nematode genes in one group, with Family 5, subfamily 2, glycosyl hydrolases
from Scotobacteria and Bacilliaceae as the most homologous groups. The overall
amino acid sequence identity among the four nematode cellulases was from 71 to
83%, and the amino acid sequence identity to bacterial Family 5 cellulases ranged
from 33 to 44%. The eukaryotic organization of the four cyst nematode cellulases
suggests that they share a common ancestor, and their strong homology to
prokaryotic glycosyl hydrolases may be indicative of an ancient horizontal gene
transfer.
PMID- 9767114
TI - Experimental protocol for studying delayed effects of in vitro ischemia on
neurotransmitter release from brain slices.
AB - The mechanisms by which ischemic injury leads to delayed neuronal death are not
completely understood. Notably, no data are so far available on the modifications
in neurosecretory responses evoked by a period of ischemia. Superfused brain
slices represent a useful preparation in studying the effects of in vitro
ischemia on neurotransmitter release. Using this experimental model we describe a
protocol which allows to study not only the immediate effects of an ischemic
insult, but also, more interestingly, its delayed (1 h) effects on the release of
different neurotransmitters. A first pulse (S1) of 50 mM KCl was applied at the
60th min of perfusion and a second one was applied at the 210th min (S2). In
vitro ischemia was performed from the 120th to the 150th min, during the
inclusive period between the two depolarizing stimuli. The delayed effects of the
ischemic treatment on slice response to KCl were calculated as S2/S1 ratio. This
protocol allows to study neurotransmitter release mechanisms associated with
postischemic neuronal death. Moreover it will be useful in the evaluation of the
neuroprotective potential of new drugs.
PMID- 9767115
TI - Effect of dietary (n-9), (n-6) and (n-3) fatty acids on membrane lipid
composition and morphology of rat erythrocytes.
AB - Studies focused on the intake of different dietary fats have shown changes in
membrane lipid composition and, as a result, alterations in membrane physical
properties. These changes affect erythrocyte morphology, receptor activity and
oxygen transport, among others. Here, we compare the effects of diets exclusively
differing in the type of fat (olive oil rich in monounsaturates, sunflower oil
rich in n-6 polyunsaturates and fish oil rich in n-3 polyunsaturates) on fatty
acid composition of plasma and erythrocyte membranes and erythrocyte morphology
under scanning electron microscopy in rats. Monounsaturates are highest in
animals fed olive oil diets; as are linoleic and arachidonic acids in sunflower
oil-fed animals and n-3 PUFAs in fish oil-fed animals. The lowest levels of
arachidonic acid are found in fish oil-fed animals and so are n-3 PUFAs in
sunflower oil-fed animals. Our results show that sunflower oil-fed animals
present lower discocyte, the major cell shape related to tissue oxygen supply,
and higher codocyte percentages than olive oil- and fish oil-fed groups.
Echinocyte percentage is higher in fish oil-fed animals with respect to the other
two groups. The collective data indicate that olive oil elevates monounsaturates
and the number of discocytes, pointing out a possible beneficial aspect of this
dietary fat.
PMID- 9767116
TI - Positive and negative control of Serrate expression during early development of
the Drosophila wing.
AB - The product of the Drosophila gene Serrate acts as a short-range signal during
wing development to induce the organising centre at the dorsal/ventral
compartment boundary, from which growth and patterning of the wing is controlled.
Regulatory elements reflecting the early Serrate expression in the dorsal
compartment of the wing disc have recently been confined to a genomic fragment in
the 5'-upstream region of the gene. Here we present data to suggest that this
fragment responds to various positive and negative inputs required for the early
Serrate expression. First, activation and maintenance of expression in the dorsal
compartment of the wing discs of second and early third instar larvae depends on
apterous, as revealed by reporter gene expression in discs either lacking or
ectopically expressing apterous. Second, transcriptional downregulation during
third larval instar is mediated by hiiragi. Finally, this regulatory element
responds to Delta signalling in a nonautonomous way to maintain Serrate
expression along the dorsal margin. The results clearly show that some of the
previously described transactivators of Serrate protein expression, e.g. fringe,
act on elements required for later aspects of Serrate expression.
PMID- 9767117
TI - Parallel regional quantification of choline acetyltransferase and cholinesterase
activity in the central nervous system of an invertebrate (Sepia officinalis).
AB - The present study describes (i) a procedure to dissect the central nervous system
of the cuttlefish (Cephalopod) into ten, functionally distinct, anatomical
regions of interest and (ii) the parallel measurement of acetylcholine synthesis
(choline acetyltransferase) and degradation (cholinesterase) activities. Both
aspects (dissection and parallel quantification of acetylcholine synthesis and
degradation) could be of great importance for quantitative regional studies in
neurochemistry in this animal model, it is interesting to study the cellular and
molecular mechanisms involved in learning and aging processes. The parallel
quantification of acetylcholine synthesis and degradation applicable to any
animal model is pivotal since both enzymes are essential for the cholinergic
neurotransmission and may be differentially modulated by specific functions such
as learning and aging processes. Furthermore, since choline acetyltransferase and
cholinesterase show different localization into the brain, their parallel
quantification may underlie the involvement of cholinesterase in non-cholinergic
functions, which remain unclear throughout the animal kingdom.
PMID- 9767118
TI - cDNA cloning of two splice variants of a human copper-containing monoamine
oxidase pseudogene containing a dimeric Alu repeat sequence.
AB - Two alternatively spliced transcripts, psiHLAO1 and psiHLAO2, of a copper
containing monoamine oxidase pseudogene have been isolated from a human-liver
cDNA library. The larger psiHLAO1 cDNA (2073bp) contains a 5'-flanking segment of
134bp, followed by an apparent open reading frame (ORF) of 1725bp. The deduced
amino acid sequence of this ORF (574 residues) shares 81.0% similarity with the
763-residue monoamine oxidase from human placenta (HPAO) (the N-terminal 533
residues of psiHLAO1 share 86.7% similarity with HPAO). The psiHLAO1 ORF is
interrupted by an in-frame stop codon corresponding to amino acid 225 and
terminates within a type S(a) dimeric Alu repeat sequence. psiHLAO2 appears to be
an alternatively spliced variant of psiHLAO1 that has 413 bases of psiHLAO1
excised according to the 'GT-AG' rule. The slightly longer 3' end of the psiHLAO2
transcript shows that the Alu repeat is followed by an 11-bp poly(A) tract that,
in turn, is followed by an AT-rich (81%) sequence of 105bp. A reverse
transcriptase-polymerase chain reaction (RT-PCR) protocol was used to confirm
that both psiHLAO1 and psiHLAO2 are transcribed in human liver and placenta. A
search of the expressed sequence tag (EST) database indicates that, like HPAO,
psiHLAO derives also from the region 17q21 of the human genome.
PMID- 9767119
TI - Chemical cross-linking of ethidium to DNA by glyoxal.
AB - Ethidium was found to be efficiently cross-linked to DNA by glyoxal. Kinetic
studies showed that the rate of the cross-linking reaction is strongly dependent
on the glyoxal concentration. Comparative studies using a series of
phenanthridines and acridines showed that NH2 groups at both the 2 and 7
positions on the phenanthridine ring are necessary for efficient cross-linking.
Studies using synthetic polydeoxynucleotides showed that the 2-amino group of
guanine is absolutely required for cross-linking. Fluorescence contact energy
transfer and relative viscosity experiments showed that the cross-linked drug
remains intercalated into DNA. DNA gel electrophoresis and melting studies
demonstrated that cross-linked ethidium does not dissociate the DNA double helix
to single strands.
PMID- 9767120
TI - Molecular organisation of amphotericin B at the air-water interface in the
presence of sterols: a monolayer study.
AB - Using the monolayer technique to study the surface behaviour of systems
consisting of amphotericin B (AmB) and various sterols, the components were found
to interact with each other. The interactions observed are accounted for by
postulating that, at low surface pressures, AmB and different sterols form mixed
films where the former lies parallel and the latter normal to the air-water
interface in such a way that the polar groups in both components establish
hydrogen bonds that lead to the formation of an AmB-sterol 'complex' of 2:1
stoichiometry at the interface. At high surface pressures, AmB molecules
rearrange themselves normal to the interface; this gives rise to the Van der
Waals interactions between non-polar chains of both components that vary with the
nature and composition of the system. The occurrence of these hydrophobic
interactions prevents the desorption of AmB into the subphase, which is
consistent with the positive excess areas of mixing obtained under these surface
pressure conditions. Among the four sterols studied, ergosterol exhibits the
strongest interaction with AmB and beta-sitosterol the weakest. Cholesterol and
stigmasterol show intermediate behaviour.
PMID- 9767121
TI - Effect of beta-cyclodextrin dietary supplementation on biliary proteins and their
resulting cholesterol nucleating activity in pigs.
AB - We explored the possibility that the biliary protein fraction may support part of
the variation in the nucleating activity previously measured in gallbladder biles
of pigs. Eighteen gallbladder aspirates freshly obtained from three dietary
groups (0, 5, or 10% beta-cyclodextrin) of six pigs were chromatographed to
purify their total protein fraction. Proteins were quantified, and analysed
through electrophoresis and immunoblotting or enzyme-linked immunosorbent assay
for albumin, and five putative effectors of cholesterol crystallisation, mucins,
immunoglobulin A, 130 kDa, apolipoprotein A-I, and anionic polypeptide fraction.
Each total protein fraction was also assayed for its ability to influence
cholesterol precipitation, when added to supersaturated model bile. The current
data provided evidence that the cholesterol crystallisation-promoting activity of
biliary proteins in model biles increased with the beta-cyclodextrin dietary
content. This occurred without any significant change in the total biliary
protein content, but was associated with a significant decrease in the
concentration of albumin and apolipoprotein A-I, resulting in changes in the
overall balance of proteins in bile. Comparison of these results with the
crystallisation figures previously obtained from the corresponding native biles
led us to conclude that biliary proteins might influence the outcome of the
crystallisation process, namely the final crystal concentration at equilibrium,
but would not systematically represent a major driving force for determining the
velocity of crystal formation in native bile of pigs.
PMID- 9767122
TI - Cryopreservation of rat cortical synaptosomes and analysis of glucose and
glutamate transporter activities, and mitochondrial function.
AB - Direct comparisons of synaptic functional parameters in brain tissues from
different groups of experimental animals and different samples from post mortem
human brain are often hindered by the inability to perform assays at the same
time. To circumvent these difficulties we developed methods for cryopreservation
and long-term storage of neocortical synaptosomes. The synaptosomes are suspended
in a cryopreservation medium containing 10% dimethylsulfoxide and 10% fetal
bovine serum, and are slowly cooled to -80 degreesC and then stored in liquid
nitrogen. The function of plasma membrane glucose and glutamate transporters, and
mitochondrial electron transport activity and membrane potential were measured in
fresh, cryopreserved (CP), and non-cryopreserved freeze-thawed (NC) synaptosomes.
Glucose and glutamate transporter activities, and mitochondrial functional
parameters in CP synaptosomes were essentially identical to those in fresh
unfrozen synaptosomes. Glucose and glutamate transport were severely compromised
in NC synaptosomes, whereas mitochondrial function and cellular esterase activity
were largely maintained. Electron paramagnetic resonance studies in conjunction
with a protein-specific spin label indicated that cryopreservation did not alter
the physical state of synaptosomal membrane proteins. These methods provide the
opportunity to generate stocks of functional synaptosomes from different
experiments or post mortem samples collected over large time intervals.
PMID- 9767123
TI - The mouse Fkh1/Mf1 gene: cDNA sequence, chromosomal localization and expression
in adult tissues.
AB - The 'winged helix' or 'forkhead' transcription factor gene family is defined by a
common 100-amino-acid DNA-binding motif. Here, we describe the chromosomal
position, start site of transcription, sequence and adult expression pattern of
the mouse Fkh1/Mf1 (Forkhead homologue 1/mesoderm/mesenchyme forkhead 1) gene.
This gene contains one exon and encodes a protein of 553 amino acids that is
highly related to the mouse MFH1 protein. The Fkh1/Mf1 mRNA is expressed widely
in adult tissues. Linkage analysis showed that the Fkh1/Mf1 gene is localized to
chromosome 13 at 17.02cM from the centromer, in close proximity to Bmp6 and Hfh1,
another distinct member of the winged helix gene family.
PMID- 9767124
TI - Selective expression of specific histone H4 genes reflects distinctions in
transcription factor interactions with divergent H4 promoter elements.
AB - Expression of many histone H4 genes is stringently controlled during the cell
cycle to maintain a functional coupling of histone biosynthesis with DNA
replication. The histone H4 multigene family provides a paradigm for
understanding cell cycle control of gene transcription. All functional histone H4
gene copies are highly conserved in the mRNA coding region. However, the putative
promoter regions of these H4 genes are divergent. We analyzed three
representative mouse H4 genes to assess whether variation in H4 promoter
sequences has functional consequences for the relative level and temporal control
of expression of distinct H4 genes. Using S1 nuclease protection assays with gene
specific probes and RNA from synchronized cells, we show that the mRNA level of
each H4 gene is temporally coupled to DNA synthesis. However, there are
differences in the relative mRNA levels of these three H4 gene copies in several
cell types. Based on gel shift assays, nucleotide variations in the promoters of
these H4 genes preclude or reduce binding of several histone gene transcription
factors, including IRF2, HiNF-D, SP-1 and/or YY1. Therefore, differential
regulation of H4 genes is directly attributable to evolutionary divergence in H4
promoter organization which dictates the potential for regulatory interactions
with cognate H4 transcription factors. This regulatory flexibility in H4 promoter
organization may maximize options for transcriptional control of histone H4 gene
expression in response to the onset of DNA synthesis and cell cycle progression
in a broad spectrum of cell types and developmental stages.
PMID- 9767125
TI - Water-absorbent polymer as a carrier for a discrete deposit of antisense
oligodeoxynucleotides in the central nervous system.
AB - One of the problems of introducing antisense oligodeoxynucleotides (ODN) into the
central nervous system (CNS) is their rapid disappearance from the target site
due to their dispersion and diffusion, which results in poor uptake and/or
retention in cells (M. Morris, A.B. Lucion, Antisense oligonucleotides in the
study of neuroendocrine systems, J. Neuroendocrinol. 7 (1995) 493-500; S. Ogawa,
H.E. Brown, H.J. Okano, D.W. Pfaff, Cellular uptake of intracerebrally
administrated oligodeoxynucleotides in mouse brain, Regul. Pept. 59 (1995) 143
149) [2,5]. Recently, we adapted a new method using water-absorbent polymer (WAP;
internally cross-linked starch-grafted-polyacrylates) as a carrier for antisense
ODN. The polymer forms a hydro-gel after absorbing water which is chemically and
biologically inert. In these studies, the polymer (powder-form) is fully swollen
by physiological saline containing antisense ODN (0.2 micromol/ml) to make 80
fold volume gel. Hydro-gel (1 microliter) is injected into the target site, and
water solutes are assumed to be diffused stoichiometrically into CNS from the
surface of the gel. Histological studies indicate that 24 h after the injection,
antisense ODN (5'biotinylated-S-oligos of 15 mer) are distributed to within 800
micrometer from the edge of the area where the gel is located and then gradually
disappear from this area within days, but still remain within 300-micrometer
distance 7 days later. Antisense ODN are effectively incorporated by all the cell
types examined, i.e., neurons, astrocytes and microglias, and suppress the
synthesis of the target protein. This method can be adapted to slow delivery of
antisense ODN and other water soluble substances into the CNS.
PMID- 9767126
TI - A chemotaxis cluster from Agrobacterium tumefaciens.
AB - We report the DNA sequence of a 9.6-kb region of the Agrobacterium tumefaciens
chromosome containing a putative 8-kb chemotaxis operon. The putative operon
begins with orf1, whose predicted protein product shows strong sequence identity
to methyl-accepting chemotaxis proteins (MCPs), followed by orf2, cheY1, cheA,
cheR, cheB, cheY2, orf9, orf10. All of the identified homologues show a high
degree of sequence conservation with their counterparts in the che operons from
Sinorhizobium meliloti and Rhodobacter sphaeroides, and are arranged in a similar
order. Mutations in orf1 and cheA result in impaired chemotaxis, whereas deletion
of orf10, appears to have no effect on chemotaxis or motility. Although the
putative operon does not contain a cheW homologue, heterologous probing and PCR
using consensus primers indicates that cheW maps elsewhere in the Agrobacterium
genome.
PMID- 9767127
TI - Evidence of local conformational fluctuations and changes in bacteriorhodopsin,
dependent on lipids, detergents and trimeric structure, as studied by 13C NMR.
AB - We examined how the local conformation and dynamics of [3-13C]Ala-labeled
bacteriorhodopsin (bR) are altered as viewed from 13C NMR spectra when the
natural membrane lipids are partly or completely replaced with detergents. It
turned out that the major conformational features of bR, the alphaII-helices, are
generally unchanged in the delipidated or solubilized preparations. Upon partial
delipidation or detergent solubilization, however, a significant conformational
change occurs, ascribed to local conversion of alphaII-->alphaI-helix (one Ala
residue involved), evident from the upfield displacement of the transmembrane
helical peak from 16.4 ppm to 14.5 ppm, conformational change (one or two Ala
residues) within alphaII-helices from 16.4 to 16.0 ppm, and acquired flexibility
in the loop region (especially at the F-G loop) as manifested from suppressed
peak-intensities in cross-polarization magic angle spinning (CP-MAS) NMR spectra.
On the other hand, formation of monomers as solubilized by Triton X-100, Triton N
101 and n-dodecylmaltoside is characterized by the presence of a peak at 15.5 ppm
and a shifted absorption maximum (550 nm). The size of micelles under the first
two conditions was small enough to yield 13C NMR signals observable by a solution
NMR spectrometer, although 13C CP-MAS NMR signals were also visible from a
fraction of large-sized micelles. We found that the 16.9 ppm peak (three Ala
residues involved), visible by CP-MAS NMR, was displaced upfield when Schiff base
was removed by solubilization with sodium dodecyl sulfate, consistent with our
previous finding of bleaching to yield bacterioopsin.
PMID- 9767128
TI - Cloning and identification of a phospholipase gene from vibrio mimicus.
AB - The phospholipase gene phl was identified from Vibrio mimicus (ATCC33653) and
sequenced. The entire open reading frame (ORF) was composed of 1410 nucleotides
and encoding 470 amino acids. The phl was placed upstream of hemolysin gene
(vmhA) with opposite direction of transcription. From the BLAST search program,
the deduced amino acids sequence showed 74.4% identity with phospholipase gene
(lec) from V. cholerae El Tor. The entire ORF of phospholipase gene was amplified
by PCR and inserted into an Escherichia coli expression vector, pET22b(+) and
introduced E. coli BL21(DE3). SDS-PAGE demonstrated that a protein corresponding
to the phospholipase was overexpressed and migrated at a molecular mass of 53
kDa.
PMID- 9767129
TI - Quantification of a neurotrophin receptor from submilligram quantities of brain
tissue using western blotting.
AB - The immunodensity of the trkB neurotrophin receptor was quantified from
submilligram quantities of brain tissue, using approximately 500 microgram
samples dissected from the cochlear nucleus (CN) of adult guinea pigs. Tissue
samples were hand-homogenized in a lysis buffer. After complete lysis, an aliquot
of the lysate was taken to measure total protein, and the remainder was
denatured. Proteins in the denatured aliquot were separated by sodium dodecyl
sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and electrophoretically
transferred onto an immoblin-P membrane. The membrane was exposed to rabbit anti
trkB and then to anti-rabbit IgG HRP conjugate. The immuno-complex on the
membrane was detected by chemiluminescence, which was recorded on
autoradiographic film. Autoradiographs were scanned into a computer and the trkB
immunobands were quantified by densitometry. This procedure allowed the
quantitative comparison of trkB neurotrophin receptor immunodensities between
tissue samples. The procedure can be applied to the analysis of small samples of
tissue collected from different brain regions or collected from the same region
at different times, such as during development or aging, after administering a
drug, or after placing a lesion.
PMID- 9767130
TI - Palmitoylation of rhodopsin with S-protein acyltransferase: enzyme catalyzed
reaction versus autocatalytic acylation.
AB - Protein palmitoylation in vitro was studied using bovine rhodopsin as the
substrate and a partially purified acylating enzymatic activity (PAT) from
placental membranes. PAT incorporates fatty acid into rhodopsin with higher
efficiency (10 times higher initial rate), as compared to autoacylation. The
activity is sensitive to heat and trypsin, indicating a protein-mediated
enzymatic process and requires the native conformation of rhodopsin. The presence
of deacylated, free cysteine residues in dark-adapted rhodopsin increases
palmitoylation via PAT. The sites for non-enzymatic and enzymatic palmitoylation
could not be distinguished by peptide mapping. The reversible palmitoylation
described here will provide a tool for the study of the role of palmitoylation in
photoreceptor function.
PMID- 9767132
TI - A fourth gene from the Candida albicans CDR family of ABC transporters.
AB - Using primers derived from a region of the Candida albicans CDR1 (Candida drug
resistance) gene that is conserved in other ABC (ATP-binding cassette)
transporters, a DNA fragment from a previously unknown CDR gene was obtained by
polymerase chain reaction (PCR). After screening a C. albicans genomic library
with this fragment as a probe, the complete CDR4 gene was isolated and sequenced.
CDR4 codes for a putative ABC transporter of 1490 amino acids with a high degree
of homology to Cdr1p, Cdr2p and Cdr3p from C. albicans (62, 59 and 57% amino acid
sequence identity, respectively). Cdr4p has a predicted structure typical for
cluster I. 1 of yeast ABC transporters, characterized by two homologous halves,
each comprising an N-terminal hydrophilic domain with consensus sequences for ATP
binding and a C-terminal hydrophobic domain with six transmembrane helices. In
contrast to the CDR1/CDR2 genes, the genetic structure of the CDR4 gene was
conserved in 59 C. albicans isolates from six different patients. Northern
hybridization analysis showed that the CDR4 gene was expressed in most isolates,
but no correlation between CDR4 mRNA levels and the degree of fluconazole
resistance of the isolates was found. In addition, a C. albicans mutant in which
both copies of the CDR4 gene were disrupted by insertional mutagenesis was not
hypersusceptible to fluconazole as compared to the parent strain. Unlike CDR1 and
CDR2, CDR4 does not, therefore, seem to be involved in fluconazole resistance in
C. albicans.
PMID- 9767131
TI - Differential expression patterns of Wnt genes in the murine female reproductive
tract during development and the estrous cycle.
AB - The murine female reproductive tract differentiates during postnatal development.
This process of cytodifferentiation and morphogenesis is dependent upon specific
mesenchymal-epithelial interactions as well as circulating steroid hormones
(Cunha, G.R., 1976. Int. Rev. Cytol. 47, 137-194; Pavlova, A. et al., 1994.
Development 120, 335-346). Members of the Wnt family of signaling molecules have
been recently identified in this system (Pavlova, A. et al., 1994. Development
120, 335-346; Bui, T.D. et al., 1997. Br. J. Cancer 75, 1131-1136; Miller, C.,
Sassoon, D.A., 1998. Development, in press). We describe the expression patterns
of Wnt genes in the developing and adult female reproductive tract. Additionally,
we note that changes in the levels of expression occur during the estrous cycle.
Wnt gene expression patterns are regulated by the presence of epithelium in
tissue graft experiments, suggesting that Wnt genes may indeed play roles in the
mesenchymal-epithelial interactions critical for female reproductive tract
development and function.
PMID- 9767133
TI - Asymmetrical membrane fluidity of bovine adrenal chromaffin cells and granules
and effect of trichosporin-B-VIa.
AB - We examined membrane fluidity of bovine adrenal chromaffin cells and chromaffin
granules using cationic trimethylammonium derivative of diphenylhexatriene (TMA
DPH) as a fluorescence probe. After adding TMA-DPH to the suspension of
chromaffin cells and that of granules, it first bound to the outer layer of the
plasma membrane of the cells and that of the granule membrane, then gradually
penetrated the inner layer of each membrane and distributed to both leaflets of
the respective membranes. Accompanying increases in the ratio of incorporated
probe on the cytoplasmic side of the chromaffin cell membrane, its fluorescence
anisotropy gradually decreased. However, in chromaffin granules, the fluorescence
anisotropy gradually increased with increases in the ratio of incorporated probe.
These findings suggest that the inner layer of the plasma membrane and outer
layer of the granular membrane are more fluid than the corresponding side of each
membrane, which is suitable for the fusion between both membranes. We also
examined the effect of trichosporin-B-VIa, a fungal ion channel forming alpha
aminoisobutyric acid-containing peptide, on the fluidity of chromaffin cells
using TMA-DPH. The peptide decreased the fluorescence anisotropy and increased
the fluorescence intensity in the concentration range that induced Ca2+ dependent
catecholamine secretion, suggesting that a change in lipid dynamics of the lipid
bilayer of the plasma membrane was induced by this peptide.
PMID- 9767134
TI - A mobile intracellular microelectrode designed to record from neurons in
contracting tissue.
AB - Intracellular recording from neurons in moving tissue allows data to be gathered
in circumstances that are physiologically more realistic than those requiring
pharmacological or mechanical suppression of movement. The construction of a
mobile, suspended microelectrode assembly is described. Short glass
microelectrodes were attached to a flexible length of 100 micrometer silver wire.
A finer wire was inserted in the shank of the microelectrode to carry the
electrical signal. Recordings were made from myenteric neurons of the guinea pig
ileum, which was moving during the recording session. Intracellular recordings
were maintained while the electrodes followed movements of 1 mm or more.
PMID- 9767135
TI - Characterization of the gene for human EMMPRIN, a tumor cell surface inducer of
matrix metalloproteinases.
AB - EMMPRIN (extracellular matrix metalloproteinase inducer) also known as CD147 and
basigin, is a member of the immunoglobulin family that is present on the surface
of tumor cells and stimulates nearby fibroblasts to synthesize matrix
metalloproteinases. Using our EMMPRIN cDNA, we have isolated a cosmid clone that
contains the human EMMPRIN gene. S1 analysis with a fragment of the gene clone
and primer extension of the mRNA was performed to determine the transcription
start site. PCR and sequence analysis have defined the exon/intron organization
of the gene and show that it is highly conserved with the mouse EMMPRIN/basigin
gene. About 950 bases of the 5'-flanking region were examined for transcription
factor consensus binding sites, locating three SP1 sites and two AP2 sites. The
transcription start site was found to be located in a CpG island. Elements in the
proximal promoter region were conserved in the human and mouse genes.
PMID- 9767136
TI - Micelle formation of sodium cholate and solubilization into the micelle.
AB - The micellization of sodium cholate (NaC) was studied at 298.2 K by aqueous
solubility at different pH values. Using a stepwise association model of cholate
anions without the sodium counterion, the aggregation number (n) of the cholate
micelle was evaluated and found to increase with the total concentration,
indicating that the mass action model worked quite well. The n value at 60 mM was
found equal to 16. The membrane potential measurement of sodium ion with a cation
exchange membrane was made in order to confirm the low counterion binding to
micelle. The solubilization of alkylbenzenes (benzene, toluene, ethylbenzene, n
propylbenzene, n-butylbenzene, n-pentylbenzene, n-hexylbenzene) and polycyclic
aromatic compounds (naphthalene, anthracene, pyrene) into the aqueous micellar
solution of sodium cholate was carried out. Solubilizate concentrations at
equilibrium were determined spectrophotometrically at 298.2 K. The first stepwise
association constants (K1) between solubilizate monomer and vacant micelle were
evaluated from the equilibrium concentrations and found to increase with
increasing hydrophobicity of the solubilizate molecules. From the Gibbs energy
change for solubilization at the different mean aggregation numbers and from
molecular structure of the solubilizates, the function of sodium cholate micelle
for solubilization was discussed and was compared with data from conventional
aliphatic micelles.
PMID- 9767137
TI - Cognitive dysfunction and histological findings in rats with chronic-stage
contusion and diffuse axonal injury.
AB - The Morris water maze (MWM) technique is well known as a prominent method of
evaluating learning acquisition and memory retention impairments in rats. We
previously reported on a modified fluid percussion device that is able to
consistently produce experimental cortical contusion (CC) and diffuse axonal
injury (DAI) in separate groups of rats. The purpose of the present protocol is
to evaluate the differences in learning acquisition and memory retention
impairments between these two types of injured rats in the chronic stage using
the MWM technique. CC and DAI rats are respectively induced by lateral and
midline fluid percussion. We also compare the histological differences between
these two different types of traumatic brain injury. The results show
statistically significant differences in learning acquisition impairment between
the sham and CC rats and between the sham and DAI rats. However, a difference in
memory retention impairment was expected to be seen only between the sham and DAI
rats. Histologically, the loss of CA3 pyramidal cells in the hippocampus was
observed ipsilaterally in the CC and bilaterally in DAI. Neuronal cell loss was
observed in bilaterally in layer II of the entorhinal cortex in DAI, but not in
CC.
PMID- 9767138
TI - Role of sonic hedgehog in branchiomotor neuron induction in zebrafish.
AB - The role of zebrafish hedgehog genes in branchiomotor neuron development was
analyzed by examining mutations that affect the expression of the hedgehog genes
and by overexpressing these genes in embryos. In cyclops mutants, reduction in
sonic hedgehog (shh) expression, and elimination of tiggy-winkle hedgehog (twhh)
expression, correlated with reductions in branchiomotor neuron populations.
Furthermore, branchiomotor neurons were restored in cyclops mutants when shh or
twhh was overexpressed. These results suggest that Shh and/or Twhh play an
important role in the induction of branchiomotor neurons in vivo. In sonic-you
(syu) mutants, where Shh activity was reduced or eliminated due to mutations in
shh, branchiomotor neurons were reduced in number in a rhombomere-specific
fashion, but never eliminated. Similarly, spinal motor neurons were reduced, but
not eliminated, in syu mutants. These results demonstrate that Shh is not solely
responsible for inducing branchiomotor and spinal motor neurons, and suggest that
Shh and Twhh may function as partially redundant signals for motor neuron
induction in zebrafish.
PMID- 9767139
TI - Characterization of a heat modifiable protein, Escherichia coli outer membrane
protein OmpA in binary surfactant system of sodium dodecyl sulfate and
octylglucoside.
AB - A membrane protein, OmpA of Escherichia coli, in the process of refolding from
its heat-modified form in the presence of sodium dodecyl sulfate (SDS) to its non
heated one by the addition of systematic amounts of octylglucoside (OG) was
characterized by means of dynamic light scattering and the size exclusion
chromatography combined with low angle laser light scattering photometry. Upon
heating in the presence of SDS only, the amount of SDS bound to OmpA was
increased from 1.8 to 2.3 g/g of protein and its hydrodynamic radius increased
from 3.7 to 4.7 nm. On the addition of OG, the once denatured OmpA regained its
original size above the weight fraction of OG in the total amount of surfactants,
0.8. During the process, the hydrodynamic radius was observed to decrease
cooperatively at the weight fraction of 0.6, while no change took place in the
molar mass of the protein. The refractive index increment of OmpA reflecting the
amount of surfactant binding also regained the value before the heating in
parallel with the change of size. Examination of the amount of surfactants bound
to the membrane protein according to known properties of the binary surfactant
micellar system of the surfactants showed that SDS was principally responsible
for the denaturing phenomena of OmpA.
PMID- 9767140
TI - Using GADlacZ transgenic mice as a marker system for homotopic transplantation.
AB - Olfactory bulb (OB) transplantation is a well characterized model that has been
widely used for studying neuronal plasticity and regeneration [G. Sekerkova, Z.
Katarova, E. Mugnaini, F. Joo, J.R. Wolff, S. Prodan, G. Szabo, Intrinsically
labeled relay neurons of homotopic olfactory bulb transplants establish proper
afferent and afferent synaptic connections with host neurons, Neuroscience, 80
(1997) 973-979 [10]; G. Sekerkova, Z. Malatova, J. Orendacova, T. Zigova,
Transplantation of dorsal root ganglion into the olfactory bulb of neonatal rats:
a histochemical study, Restor. Neurol. Neurosci., 6 (1993) 1-8 [11]; E. Racekova,
I. Vanicky, T. Zigova, Correlation of functional alteration with lesion extent
after olfactory bulbectomy in rats, Int. J. Neurosci., 79 (1994) 13-20 [12]; T.
Zigova, P.P.C. Graziadei, A.G. Monti Graziadei, Olfactory bulb transplantation
into the olfactory bulb of neonatal rats: an autoradiographic study, Brain Res.,
539 (1991) 51-58 [13]]. In previous studies, the OB grafts have been routinely
labeled by tritiated thymidine [S.M. Onifer, L.A. White, S.R. Whittemore, V.R.
Holets, In vitro labelling strategies for identifying primary neural tissue and
neuronal cell line after transplantation in the CNS, Cell Transplant., 2 (1993)
131-149 [7]; [13]] allowing distinction of graft from the surrounding tissue by
the presence of silver grains over the cell nuclei of the transplant. However,
this approach has some disadvantages, namely: partial or insufficient labeling of
a defined neuronal subclasses due to the length of the period of their
generation, variation in the number of labeled cells due to differences in the
gestation stage between individual embryos at the time of i.p. injection of
tritiated thymidine, inability to follow the dendritic arborization and axonal
outgrowth of the transplanted neurons or to detect directly their actual synaptic
contacts, and finally, the need to work with radioactive isotopes. In this paper,
we describe an alternative approach, in which the donor OBs in a homotopic OB
transplantation were derived from transgenic mice carrying the bacterial gene
lacZ under control from the regulatory region of GAD67 gene. In these mice, beta
galactosidase (beta-gal), encoded by lacZ is stably, ectopically expressed in the
vast majority of mitral/tufted (M/T) cells of the OB and served as their
intrinsic cellular marker in the OB transplant. By using a simple histochemical
reaction for beta-gal or immunocytochemistry with anti-beta-gal antibody, we
could detect the cell bodies and processes of the donor M/T cells and their
synaptic contacts with host neurons after long-term survival using both light and
electron microscopy. Given the great number of existing transgenic mouse lines
that express in the nervous system, this approach may have an even wider
application in neural transplantation.
PMID- 9767141
TI - NCL1, a novel gene for a non-essential nuclear protein in Saccharomyces
cerevisiae.
AB - The nucleolar protein Nop2p is an essential gene product that is required for pre
rRNA processing and ribosome biogenesis in Saccharomyces cerevisiae (Hong, B. et
al., 1997, Mol. Cell. Biol., 17, 378-388). A search for proteins similar to Nop2p
identified a novel yeast gene product that also shares significant homology with
the human proliferation associated nucleolar protein p120. The gene encoding this
78kDa protein was termed NCL1 (for nuclear protein 1; corresponding to YBL024w).
Ncl1p and Nop2p contain an evolutionarily conserved motif that has been termed
the 'NOL1/NOP2/fmu family signature' (NOL1 encodes p120). Epitope tagged Ncl1p
was found to be localized to the nucleus, including the nucleolus, and was
concentrated at the nuclear periphery. NCL1 is not essential. Strains containing
a disruption of NCL1, or strains overexpressing NCL1, grow essentially
identically to wildtype NCL1 strains on a number of different media and at
different temperatures. Disruption of NCL1 does not affect steady-state levels of
large and small ribosome subunits, monoribosomes, and polyribosomes. However,
disruption of NCL1 leads to increased sensitivity to the antibiotic paromomycin.
PMID- 9767142
TI - Unmyristoylated MARCKS-related protein (MRP) binds to supported planar
phosphatidylcholine membranes.
AB - We have recently shown that unmyristoylated MARCKS-related protein (MRP) does not
bind to neutral phospholipid vesicles, unless negatively charged phospholipids
are present. Similar behaviour has also been reported for MARCKS itself. Here we
have compared the binding of MRP to neutral and negatively charged supported
planar lipid bilayer membranes (SPLM) using two-mode waveguide spectroscopy. We
find appreciable binding of unmyristoylated MRP to neutral SPLM. We propose that
hydrophobic residues in the effector domain constitute an additional factor
capable of mediating MRP-membrane interaction.
PMID- 9767143
TI - Inositol polyphosphates regulate the membrane interactions of the endosomal p100,
G-protein-related protein.
AB - The protein, p100, was previously identified as a G-protein related protein that
cycles on and off the cytoplasmic face of the endosome membrane (Traub et al.,
Biochem. J. 280 (1991) 171-178). Here we present evidence that the inositol
polyphosphates, inositol 1,4, 5-trisphosphate (IP3) and inositol hexakisphosphate
(IP6), release p100 from light-density microsomal membranes and inhibit rebinding
of p100 through receptors, which are specific for IP3 or for IP6. These receptors
can be co-extracted with p100 from the microsomes by 0.5 M Tris-HCl and, in the
soluble state, they exhibit similar binding activity towards the inositol
polyphosphates as do untreated microsomes. Soluble p100 self-aggregates and this
aggregation is blocked by both IP3 and IP6. Stimulation of permeabilized rat
basophilic leukemia (RBL-2H3) cells with carbachol, via transfected muscarinic m1
receptors, results in increased levels of inositol polyphosphates and the
quantitative release of p100 into the cytosol. This effect is reversible and
cytosolic p100 rebinds to the membrane as the levels of inositol polyphosphates
decline. These findings suggest that p100 may belong to a family of IP-binding
proteins whose intracellular localization is determined by extracellular signals.
PMID- 9767144
TI - A Ca2+- and voltage-dependent cation channel in the nuclear envelope of red beet.
AB - The patch-clamp technique was applied to study ion conductances in various
configurations of the nuclear envelope of non-enzyme-treated red beet (Beta
vulgaris L.) nuclei. With excised patches a non-selective cation channel was
observed, that was activated by micromolar concentrations of Ca2+ on the
nucleoplasmic side of the envelope. The channel activity was also voltage
dependent and the voltage threshold of channel activation changed with the
nucleoplasmic Ca2+ concentration. The most prominent conductance level was 110+/
22 pS with 150 mM KCl in the bath and pipette. The channel was permeable to small
cations: permeabilities relative to K+ were PK congruent with PNa=1, PCs=0.3, but
PCl=0.09. Calcium ions also permeated the channel with PCa=0.43, estimated from
reversal potential, or 0.14, estimated from conductance ratio. Zn2+ (1 mM) when
applied to the cytoplasmic side of the envelope blocked the channel activity
completely, while amiloride (2 mM) reduced the channel current by 86% from the
nucleoplasmic side. The properties of the whole-nucleus current (voltage-, time-
and Ca2+-dependence) paralleled those observed with excised patches. The channel
may provide a Ca2+-regulated pathway for passive diffusion of cations across the
nuclear envelope and thus may play an important role in Ca2+-dependent nuclear
processes ranging from gene transcription to apoptosis.
PMID- 9767145
TI - The specificity of proneural genes in determining Drosophila sense organ
identity.
AB - The proneural genes (atonal and the genes of the achaete-scute complex (AS-C))
are required for the selection of sense organ precursors. They also endow these
precursors with sense organ subtype information. In most of the ectoderm, atonal
is required for precursors of chordotonal sense organs, whereas AS-C are required
for those of most external sense organs, such as bristles. To address the
question of how proneural genes influence subtype identity, we have made use of
the Gal4/UAS system of misexpression. Unlike previous misexpression experiments,
we found that under specific conditions of misexpression, atonal shows high
subtype specificity of ectopic sense organ formation. Moreover, atonal can even
transform wild-type external sense organs to chordotonal organs, although scute
cannot perform the reciprocal transformation. Our evidence demonstrates that
atonal's subtype determining role is not to activate directly chordotonal fate,
but to repress the activation of cut, a gene that is necessary for external sense
organ fate, thereby freeing its precursors to follow the alternative chordotonal
organ fate.
PMID- 9767146
TI - A unique amyloidogenic apolipoprotein serum amyloid A (apoSAA) isoform expressed
by the amyloid resistant CE/J mouse strain exhibits higher affinity for
macrophages than apoSAA1 and apoSAA2 expressed by amyloid susceptible CBA/J mice.
AB - CBA/J and other inbred strains of mice that express the amyloidogenic
apolipoprotein serum amyloid A (apoSAA) apoSAA2, together with apoSAA1, are
susceptible to amyloid A (AA) amyloidosis, whereas CE/J mice that express a
single unique isoform, apoSAACEJ, are resistant. Studies indicate that CBA/JxCE/J
hybrid mice that express apoSAA2 in the presence of apoSAACEJ are protected from
amyloidogenesis. To define a mechanism by which expression of apoSAACEJ may
protect from AA formation in the presence of apoSAA2, binding of recombinant
apoSAA (r-apoSAA) isoforms, validated by N-terminal sequencing, to a murine
macrophage cell line was investigated. Maximal specific binding occurred after
incubation of radiolabeled apoSAA with IC-21 macrophages (1x105 cells/ml) for 30
min at 4 degreesC. The binding of 125I-r-apoSAA1, 125I-r-apoSAA2 and 125I-r
apoSAACEJ was specific and saturable, with an affinity (Kd) of about 2.8, 3.2 and
1.3 nM, respectively, and approximately 2-4x106 sites per cell. Competitive
binding experiments indicate apoSAACEJ binds with higher affinity to macrophages
than does either apoSAA1 or apoSAA2. We suggest that greater cellular affinity of
apoSAACEJ compared to apoSAA2 may contribute to protection from AA amyloid in
certain CBA/JxCE/J hybrid mice by interfering with interaction of apoSAA2 by
macrophages and hence either membrane associated or intracellular degradation.
PMID- 9767148
TI - Nitric oxide reduces hypophagia induced by threonine free diet in the rat.
AB - Food intake and concentrations of glutamic (GLU) and aspartic (ASP) acids in the
nucleus accumbens were monitored in male Sprague-Dawley rats fed a threonine free
diet. These variables were measured before and after an intracerebroventricular
injection of 20 nmole nitroprusside (NP), a non-enzymatic nitric oxide donor. The
same variables were also monitored in: (a) rats fed a threonine free diet and
injected with saline; (b) animals fed a standard diet and injected with
nitroprusside; (c) rats fed a standard diet and injected with saline. The results
showed that the threonine-free diet reduced food intake and GLU and ASP
concentrations in the accumbens. NP reduced the hypophagia, but it did not change
GLU and ASP levels in rats fed the threonine-free diet. In animals fed the
standard diet, NP increased GLU and ASP concentration, and food intake. No change
was found in the animals with saline injection. These findings suggest that
nitric oxide reduces the hypophagia in the rats fed a threonine-free diet. The
lack of increase in GLU and ASP concentration in the nucleus accumbens of the
hypophagic rats indicates that NP acts on hypophagia independently by GLU and
ASP.
PMID- 9767147
TI - Characterization of platyhelminth POU domain genes: ubiquitous and specific
anterior nerve cell expression of different epitopes of GtPOU-1.
AB - POU domain proteins are a large family of transcription factors that have been
identified in a variety of metazoans, from freshwater sponges, planarians and
nematodes to arthropods, echinoderms and vertebrates. Many of these proteins are
implicated in the development and establishment of the nervous system. In this
paper we describe the identification of the planarian genes GtPOU-1, GtPOU-3 and
GtPOU-4, which belong to the subclasses III and IV of POU-domain genes. Their
similarity with other members of the POU family is restricted to the POU and
homeo domains, plus some peptide sequences scattered in the linker and flanking
regions. As with other subclass III POU genes, GtPOU-1 is devoid of introns.
Axial transcript distribution by RT-PCR and immunohistochemical assays, performed
with a polyclonal antibody raised against the GtPOU-1 fusion protein, indicate
that both the GtPOU-1 transcript and protein are continuously expressed along the
antero-posterior axis. A monoclonal antibody raised against the same fusion
protein indicates that a GtPOU-1-specific epitope, probably obtained by post
translational modification, is present in neural cells from both the central and
peripheral nerve systems of the adult planarian's anterior third. Moreover, the
GtPOU-1-specific epitope shows a dynamic expression pattern during regeneration,
always marking the most anterior region of the planarian nervous system. Both the
rapid and general GtPOU-1-specific epitope modification, during posterior
regeneration, indicate that regeneration is a global process involving all
planarian regions, including those that are far from the wound, by a combination
of morphallactic and epimorphic mechanisms.
PMID- 9767149
TI - Expression and regulation of the insulin-like growth factor-1 receptor by growing
and quiescent H4IIE hepatoma.
AB - Recent evidence that insulin-like growth factor-1 (IGF-1) influences certain
properties of H4IIE hepatoma cells independent of insulin led us to examine
whether H4IIE cells express IGF-1 receptors. Competitive binding experiments
demonstrated IGF-1, but not insulin or IGF-II, could compete with [125I]IGF-1.
Chemical crosslinking detected a protein with an apparent mass of 175 kDa and its
identity as the IGF-1 receptor alpha-subunit was confirmed by Western blotting.
The apparent molecular mass of this protein decreased to 135 kDa following
deglycosylation. Immunofluorescence microscopy verified that both insulin and IGF
1 receptors were present, although measurement of IGF-1 receptor quantity
revealed they were less abundant than insulin receptors. Binding of IGF-1 was low
in growing cells and higher in a quiescent cell population. Scatchard analysis
confirmed that receptor density was increased in non-growing H4IIE cells while
there was no apparent difference in receptor affinity. Western blot analysis and
RT-PCR revealed that both protein and mRNA levels were elevated as cell growth
ceased. Interestingly, addition of insulin to quiescent H4IIE cells, which
stimulates cell proliferation, further increased IGF-1 receptor protein levels
with a peak at 12-24 h. Distinct modes of regulating IGF-1 receptor expression
are indicated.
PMID- 9767150
TI - Norepinephrine release in the amygdala in response to footshock and opioid
peptidergic drugs.
AB - These experiments used in vivo microdialysis and high-performance liquid
chromatography to examine, in rats, norepinephrine (NE) release in the amygdala
induced by footshock and systemic administration of drugs affecting the opioid
peptidergic system. A microdialysis probe was inserted into a previously
implanted guide cannula aimed at the amygdala and the rat was placed in a box
with a stainless-steel grid floor through which a single footshock was delivered.
Samples were collected and analyzed at 15-min intervals. Footshock stimulation
increased NE levels and the magnitude of the increase varied with footshock
intensity. Relative to baseline levels, intensities of 0.3, 0.7 and 1.2 mA (3 s)
induced increases of 41, 64 and 97%, respectively. NE levels returned to baseline
within 30 min after footshock stimulation. The opioid peptidergic antagonist
naloxone (1 mg/kg, i.p.) administered immediately after footshock (0.55 mA for 1
s) potentiated NE release. In contrast, the opioid peptidergic agonist beta
endorphin (10 microgram/kg, i.p.) administered after the footshock blocked the
footshock-induced increase in NE levels. The magnitude of NE release was less
when the drugs were administered without prior footshock and when the injections
were given 30 min after footshock. The findings are consistent with previous
evidence that acute, mildly stressful stimulation induces the release of NE in
the amygdala as well as with extensive pharmacological evidence indicating that
amygdala NE released by arousing stimulation is involved in regulating memory
storage and that the opioid peptidergic system influences memory storage by
modulating the release of NE in the amygdala.
PMID- 9767151
TI - Sequence and mutational analysis of the devBCA gene cluster encoding a putative
ABC transporter in the cyanobacterium Anabaena variabilis ATCC 29413.
AB - The devBCA gene cluster (dev for development), shown to be essential for envelope
formation in heterocysts of Anabaena sp. strain PCC 7120, was identified in the
gene bank of a second heterocyst-forming strain, Anabaena variabilis ATCC 29413.
Sequence and structural organization of the three genes, encoding subunits of a
presumptive ABC transporter, were nearly identical in both strains. Mutants of A.
variabilis defective in the devA gene were constructed. As devA mutants of
Anabaena 7120, A. variabilis mutants were unable to grow on N2 as sole nitrogen
source due to incomplete differentiation of heterocysts.
PMID- 9767153
TI - Craf-1 protein kinase is essential for mouse development.
AB - The three mammalian Raf serine/threonine protein kinases mediate the transduction
of proliferative and differentiative signals from a variety of cell surface
receptors to the nucleus. We report here that Craf-1 is essential for mouse
development, as its mutation results in embryonic lethality. Developmental
defects are found in mutant placentas as well as in the skin and in the lungs of
mutant embryos. Craf-1 mutants also display a generalized growth retardation
which is consistent with the ubiquitous expression of Craf-1 and which could be
due to the reduced proliferation of mutant cells. Interestingly, the time-point
of embryonal death varies depending on the genetic background. This suggests that
Craf-1-mediated signaling is affected by genetic background-specific alleles of
other genes.
PMID- 9767152
TI - Immunocytochemical localization of the NMDA-R2A receptor subunit in the cat
retina.
AB - Immunocytochemical studies were performed to determine the distribution and
cellular localization of the NMDA-R2A receptor subunit (R2A) in the cat retina.
R2A-immunoreactivity (R2A-IR) was noted in all layers of the retina, with
specific localizations in the outer segments of red/green and blue cone
photoreceptors, B-type horizontal cells, several types of amacrine cells, Muller
cells and the majority of cells in the ganglion cell layer. In the inner nuclear
layer, 48% of all cells residing in the amacrine cell layer were R2A-IR including
a cell resembling the GABAergic A17 amacrine cell. Interestingly, the AII rod
amacrine cell was devoid of R2A-IR. Although the localization of the R2A subunit
was anticipated in ganglion cells, amacrines and Muller cells, the presence of
this receptor subunit to the cells in the outer retina was not expected. Here,
both the R2A and the R2B subunits were found to be present in the outer segments
of cone photoreceptors and to the tips of rod outer segments. Although the
function of these receptor subunits in rod and cone photoreceptors remains to be
determined, the fact that both R2A and R2B receptor subunits are localized to
cone outer segments suggests a possible alternative pathway for calcium entry
into a region where this cation plays such a crucial role in the process of
phototransduction. To further classify the cells that display NR2A-IR, we
performed dual labeling experiments showing the relationship between R2A-labeled
cells with GABA. Results showed that all GABAergic-amacrines and displaced
amacrines express the R2A-subunit protein. In addition, approximately 11% of the
NR2A-labeled amacrines, did not stain for GABA. These findings support
pharmacological data showing that NMDA directly facilitates GABA release in
retina and retinal cultures [I.L. Ferreira, C.B. Duarte, P.F. Santos, C.M.
Carvalho, A.P. Carvalho, Release of [3H]GABA evoked by glutamate receptor agonist
in cultured chick retinal cells: effect of Ca2+, Brain Res. 664 (1994) 252-256;
G.D. Zeevalk, W.J. Nicklas, Action of the anti-ischemic agent ifenprodil on N
methyl-d-aspartate and kainate-mediated excitotoxicity, Brain Res. 522 (1990) 135
139; R. Huba, H.D. Hofmann, Transmitter-gated currents of GABAergic amacrine-like
cells in chick retinal cultures, Vis. Neurosci. 6 (1991) 303-314; M. Yamashita,
R. Huba, H.D. Hofmann, Early in vitro development of voltage- and transmitter
gated currents in GABAergic amacrine cells, Dev. Brain Res. 82 (1994) 95-102; R.
Ientile, S. Pedale, V. Picciurro, V. Macaione, C. Fabiano, S. Macaione, Nitric
oxide mediates NMDA-evoked [3H]GABA release from chick retina cells, FEBS Lett.
417 (1997) 345-348; R.C. Kubrusly, M.C. deMello, F.G. deMello, Aspartate as a
selective NMDA agonist in cultured cells from the avian retina, Neurochem. Intl.
32 (1998) 47-52] or reduction of GABA in vivo [N.N. Osborn, A.J. Herrera, The
effect of experimental ischaemia and excitatory amino acid agonist on the GABA
and serotonin immunoreactivities in the rabbit retina, Neurosci. 59 (1994) 1071
1081]. Since the majority of GABAergic synapses in the inner retina are onto both
rod and cone bipolar axon terminals [R.G. Pourcho, M.T. Owzcarzak, Distribution
of GABA immunoreactivity in the cat retina: A light and electron-microscopic
study, Vis. Neurosci. 2 (1989) 425-435], we hypothesize that the NMDA-receptor
plays a crucial role in providing feedback inhibition onto rod and cone bipolar
cells.
PMID- 9767154
TI - Expression of the homeobox gene GBX2 during chicken development.
AB - We have examined the expression pattern of the GBX2 gene during chicken
embryogenesis. First transcripts are found in the epiblast of a HH st. 3+ embryo.
With the onset of neurogenesis, transcripts mark the posterior neuroectoderm.
Later on, expression is detectable in the isthmic region, the hindbrain and the
neural tube. We show that GBX2 transcripts, as well as the protein, mark the
presumptive hindbrain region. After establishment of the brain vesicles GBX2
transcripts were also detected in distinct domains of the diencephalon. In
addition to neural sites of expression, GBX2 was found in several domains
including the otic vesicle, the somitic mesoderm, the lateral foregut endoderm,
the ventral limb bud ectoderm and in the feather buds.
PMID- 9767155
TI - Selective in vivo fluorescence labelling of cholinergic neurons containing
p75(NTR) in the rat basal forebrain.
AB - The cholinergic system of the rat basal forebrain is used as a model for the
homologous region in humans which is highly susceptible to neuropathological
alterations as in Alzheimer's disease. Cholinergic cells in the basal forebrain
express the low-affinity neurotrophin receptor p75NTR. This has been utilized for
selective immunolesioning of cholinergic neurons after internalization of an
immunotoxin composed of anti-p75NTR and the ribosome-inactivating toxin saporin.
However, the goal of many studies may be not the lesion, but the identification
of cholinergic cells after other experimentally induced alterations in the basal
forebrain. Therefore, a novel cholinergic marker was prepared by conjugating the
monoclonal antibody 192IgG directed against p75NTR with the bright red
fluorochrome carbocyanine 3 (Cy3). Three days after intraventricular injection of
Cy3-192IgG the fluorescence microscopic analysis revealed a pattern of Cy3
labelled cells matching the distribution of cholinergic neurons. Apparently the
marker was internalized within complexes of p75NTR and Cy3-192IgG which were then
retrogradely transported to the cholinergic perikarya of the basal forebrain. In
addition to the even labelling of somata, a strong punctate-like Cy3
immunofluorescence was seen in structures resembling lysosomes. The specificity
of the in vivo staining was proven by subsequent immunolabelling of choline
acetyltransferase (ChAT) with green fluorescent Cy2-tagged secondary antibodies.
In the medial septum, the diagonal band and the nucleus basalis only cholinergic
neurons were marked by Cy3-192IgG. In parallel experiments, digoxigenylated
192IgG was not detectable within cholinergic basal forebrain neurons after
intraventricular injection. Presumably, this modified antibody could not be
internalized. On the other hand, digoxigenylated 192IgG was found to be an
excellent immunocytochemical marker for p75NTR as shown by double labelling
including highly sensitive mouse antibodies directed against ChAT. Based on the
present findings, future applications of the apparently non-toxic Cy3-192IgG and
other antibodies for fluorescent in vivo and in vitro labelling are discussed.
PMID- 9767156
TI - Expression of Gbx-2 during early development of the chick embryo.
AB - Gbx-2 is required for the normal development of the anterior hindbrain. Since
much of our understanding of the normal development of this region derives from
studies of avian embryos, we have determined the expression of Gbx-2 in chick
embryos at stages relevant to the regionalization of the hindbrain. As the neural
plate forms transcripts already have a clear anterior limit of expression and,
subsequently, occupy a domain extending from the extreme posterior midbrain to
the rhombomere 3/4 boundary. Subsequently, expression is restricted to the
isthmus, a dorsal stripe of expression extending throughout the hindbrain in the
ventricular region and the cells adjacent to rhombomere boundaries. Transcripts
were also detected in pharyngeal endoderm, the otic placode and vesicle,
pharyngeal arches and somites.
PMID- 9767157
TI - Maternally localized RNA encoding a serine/threonine protein kinase in the
ascidian, Halocynthia roretzi.
AB - Maternally localized cytoplasmic determinants play important roles in the
embryogenesis of many animals, including ascidians. Cytoplasmic determinants are
particularly important in the determination of cell fates, and in the
establishment of the embryonic axes. Ascidians, which show mosaic development,
are good models for the study of maternal cytoplasmic determinants. Here we
report the isolation and characterization of HrPOPK-1 (Halocynthia roretzi
posterior protein kinase-1), a putative protein serine/threonine kinase. HrPOPK-1
cDNA was obtained from a Halocynthia roretzi fertilized egg cDNA library by
screening for localized RNAs using whole-mount in situ hybridization. HrPOPK-1
mRNA is strongly localized at the posterior pole of embryos. The pattern of
HrPOPK-1 mRNA localization during early embryogenesis is identical to that of
HrWnt-5 in Halocynthia roretzi, and to those of the posterior end mark (pem)
transcripts of Ciona savignyi. In addition, HrPOPK-1 shows zygotic expression in
neural tissues at the tailbud stage. These results show that the temporal
regulation of HrPOPK-1 transcription is complex.
PMID- 9767158
TI - Anti-opioid efficacy of neuropeptide FF in morphine-tolerant mice.
AB - The modulatory effects of 1DMe (d-Tyr-Leu-(NMe)Phe-Gln-Pro-Gln-Arg-Phe-NH2), an
agonist of Neuropeptide FF (NPFF) receptors, on opioid antinociceptive activity
have been compared in naive and tolerant mice in the tail-flick and the hot-plate
tests. In naive mice, 1DMe alone had no effect on pain threshold but decreased
dose-dependently (3-22 nmol) the analgesic activity of morphine in both tests. In
tolerant mice, injections of 60-fold lower doses of 1DMe (0.05-0.5 nmol) reverse
morphine-induced analgesia in the tail-flick test but this anti-opioid effect was
no longer observed with the highest doses of 1DMe tested (3-22 nmol). In the hot
plate test, the anti-opioid action of 1DMe was not detected, whatever doses
tested. Neither the NPFF-like immunoreactivity content of spinal cord and of
olfactory bulbs, nor the density of NPFF receptors in olfactory bulbs, were
altered. These results indicate that a chronic morphine treatment modifies the
pharmacological properties of NPFF but the type of pain test is crucial in
determining NPFF effects.
PMID- 9767159
TI - Expression pattern of the winged helix factor XFD-11 during Xenopus
embryogenesis.
AB - We have identified a cDNA encoding a novel Xenopus winged helix transcription
factor termed as XFD-11 (Xenopus fork head domain). The DNA binding domain is
most closely related to those of human or murine FREAC-3 (FKHL7/MF-1/FKH-1)
proteins. The XFD-11 gene is activated at late blastula/early gastrula and
transcription proceeds throughout embryogenesis. Early expression is found in
ventral and lateral but not in dorsal mesoderm. At neurula stages, transcripts
are found in posterior mesoderm except for the dorsal midline, and the gene is
also transcribed at the lateral border of the neural plate and within anterior
neuroectoderm. At later stages of development, transcripts are detected within
the pronephros, the heart, within neural crest cells surrounding the eye, in the
mandibular, hyoid and branchial arches, and within the tail.
PMID- 9767160
TI - Contribution of dopamine neurons in the medial zona incerta to the innervation of
the central nucleus of the amygdala, horizontal diagonal band of Broca and
hypothalamic paraventricular nucleus.
AB - Results of previous studies suggested that incertohypothalamic dopamine (IHDA)
neurons located in the medial zona incerta (MZI) project to the central nucleus
of the amygdala (cAMY), horizontal diagonal band of Broca (HDB), and
paraventricular nucleus (PVN). The overall goal of the present study was to
determine the relative contribution of IHDA neurons to the DA innervation of
these brain regions. A combined fluorescent and in situ hybridization
histochemical procedure was employed to localize the retrograde tracer fluoro
gold (FG) in cells expressing tyrosine hydroxylase (TH) mRNA in the MZI following
its iontophoretic injection into either the cAMY, HDB or PVN. For comparison, the
numbers of dual labeled FG/TH mRNA neurons in the midbrain were also determined.
One week after unilateral injection of FG into the cAMY, cells containing FG+TH
mRNA were found in the ipsilateral MZI, substantia nigra zona compacta (SNC) and
ventral tegmental area (VTA). The total numbers of cells labeled with FG varied
with the size of the injection site, but the ratio of dual labeling in the MZI to
that of the SNC-VTA remained constant across animals at approximately 1:6. FG
injections into the HDB resulted in a ratio of dual labeled cells in the
ipsilateral MZI and VTA of approximately 1:2, but no dual labeled cells were
found in the SNC. Dual labeled cells were only found in the ipsilateral MZI in
animals receiving FG injections in the PVN. Thus, DA terminals in the PVN
originate exclusively from IHDA neurons in the MZI, whereas these neurons provide
only a portion of the DA innervation of the cAMY and HDB. The similar
distribution of dual labeled cells in the MZI following FG injections into the
cAMY, HDB and PVN suggests that perikarya of IHDA neurons projecting to these
regions are not organized into distinct groups.
PMID- 9767161
TI - Restricted expression of the homeobox gene prox 1 in developing zebrafish.
AB - Prox 1 is a vertebrate homeobox gene which is homologous to the Drosophila
transcription factor, prospero. We have isolated a prox 1 cDNA from zebrafish,
which encodes a protein that has 82%, 84% and 83% amino acid identity with
chicken, mouse and human Prox 1, respectively. Antibodies raised against human
Prox 1 cross-react with zebrafish Prox 1 and are used here to determine the
expression patterns of Prox 1 during zebrafish embryogenesis by whole-mount
immunohistochemistry. In the 10-somite embryo, Prox 1 is expressed over the
prospective lens placode and over a broad region of epithelium extending from the
eye to the otic vesicle. As embryogenesis proceeds, Prox 1 expression in the eye
lens becomes intense, and is detected in maturing muscle pioneer cells and
superficial muscle cells. In the CNS, Prox 1 is expressed in a stripe along the
forebrain-midbrain boundary, in a segmented pattern in the ventral hindbrain, and
in selected cells of the ventral spinal cord. Additional sites of Prox 1
expression include the lateral line primordium, the trigeminal ganglia, the otic
vesicle and occasional endodermal cells.
PMID- 9767162
TI - Declines in stimulated striatal dopamine release over the first 32 h following
microdialysis probe insertion: generalization across releasing mechanisms.
AB - In a recent paper [R.R. Holson, J.F. Bowyer, P. Clausing, B. Gough,
Methamphetamine-stimulated striatal dopamine release declines rapidly over time
following microdialysis probe insertion, Brain Res. 739 (1996) 301-307] we
reported that methamphetamine-stimulated striatal dopamine release declined
rapidly over the first eight hours following microdialysis probe insertion. This
decline was strictly a function of time post-probe implantation, and not due to
tolerance or desensitization. To further examine this phenomenon, we subjected
rats to three brief pulses of several DA-releasing compounds at 2, 4 and 6 h post
probe insertion, and compared these results to those caused by a single pulse 6 h
post-insertion, or in some cases to pulses given more than 24 h post-insertion.
We found that when buproprion, a dopamine reuptake blocker, was infused briefly
into the striatum via the microdialysis probe, there was a pronounced drop in the
amount of dopamine released at 6 h vs. 2 h post-insertion; this drop was not due
to repeated exposure, since dopamine release at 6 h post-insertion was the same
for a single pulse, or when preceded by two earlier pulses. Twenty-four hours
later, buproprion-stimulated dopamine release was still lower, but did not appear
to drop further thereafter. Potassium-stimulated dopamine release, on the other
hand, dropped rapidly over the first 8 h post-insertion, and this decline
continued throughout the 24-32 h interval post-insertion. Similarly, a single
i.p. injection of 0.5 mg/kg haloperidol released three times as much dopamine
when given two compared to six hours post-implantation. Both bupropion- and
potassium-stimulated dopamine release were accompanied by declines in
extracellular DOPAC concentrations, and these declines were the same 2 or 26 h
post-insertion. In contrast, haloperidol exposure increased extracellular DOPAC,
and this haloperidol-stimulated DOPAC increase was also greatly attenuated at 6
compared to 2 h post-insertion. We conclude that there is a general decline over
time post-probe implantation in the ability of the striatal dopamine system to
release dopamine, and perhaps to increase dopamine synthesis, in response to
pharmacological challenges.
PMID- 9767163
TI - The winged helix transcription factor Hfh2 is expressed in neural crest and
spinal cord during mouse development.
AB - The embryonic neural crest is a unique group of cells that gives rise to the
peripheral nervous system as well as many other cell types. Most of the work
describing the behavior and specification of these cells has been done in the
avian system, a system amenable to experimental manipulations such as tissue
grafting, cell transplantation and lineage tracing. This work has been greatly
facilitated by the use of molecular markers of neural crest cells such as HNK-1
and slug, markers that are not yet available for the study of mouse neural crest.
Here we demonstrate that Hfh2 (HNF3 forkhead homologue 2), a member of the
'winged helix' or 'forkhead' transcription factor gene family, is expressed in
premigratory and migrating neural crest cells in the early mouse embryo and in
motorneuron progenitors in the developing spinal cord. Using linkage analysis we
have localized the Hfh2 gene to chromosome 4 at 44.91 cM from the centromere.
PMID- 9767164
TI - Microsphere embolism-induced changes in noradrenaline uptake of the cerebral
cortex in rats.
AB - The present study was undertaken to elucidate pathophysiological changes in
noradrenaline (NA) transporter and Na+/K+-ATPase, key regulators of cation
gradient across the plasma membrane, in nerve terminals of the cerebral cortex
after microsphere-induced cerebral embolism in rats. The Vmax value of NA uptake,
when analyzed by the Eadie-Hofstee plot, tended to decrease on the 1st day and
decreased on the 3rd and 7th days after the embolism without any change in the Km
value. The NA content in cerebrocortical synaptosomes did not alter on the 1st
day, but decreased on the 3rd and 7th days after the embolism. Ouabain (1 mM)
inhibited NA uptake on the 1st day, but did not alter the uptake on the 3rd and
7th days after the embolism. The activity of Na+/K+-ATPase of cerebrocortical
synaptosomes increased on the 1st day and gradually decreased up to the 7th day
after the embolim. These results suggest that NA uptake in nerve terminals of the
cerebral cortex decreased after microsphere embolism, which may be due to a
reduction in function of NA transporters. The changes in Na+/K+-ATPase following
microsphere embolism may represent a compensatory action to maintain ion
homeostasis in nerve terminals at an early stage of ischemic injury.
PMID- 9767165
TI - musculin: a murine basic helix-loop-helix transcription factor gene expressed in
embryonic skeletal muscle.
AB - We describe the embryonic expression of musculin, a new murine member of the bHLH
family of transcription factors. Musculin protein is closely related to human ABF
1, which is expressed in activated B cells, and to epicardin/capsulin/Pod-1,
which is expressed in branchial myoblasts, visceral and urogenital mesoderm and
epicardium. In situ hybridisation revealed musculin expression in embryos was
largely restricted to the embryonic skeletal muscle lineage. While all skeletal
muscles expressed the gene, only a subset of myocytes within each muscle were
positive, indicating molecular heterogeneity within fetal muscle.
PMID- 9767167
TI - Amphioxus AmphiDRAL encoding a LIM-domain protein: expression in the epidermis
but not in the presumptive neuroectoderm
AB - The sequence and developmental expression have been determined for amphioxus
AmphiDRAL, which encodes a homolog of vertebrate DRAL (down-regulated in
rhabdomyosarcoma LIM-protein). This is the first clear example of a DRAL homolog
in an invertebrate. Detectable developmental expression begins at the gastrula
stage in the epidermis, but not in the neuroectoderm; thus the early stages of
AmphiDRAL expression indicate the neural/non-neural boundary. During subsequent
embryonic stages, expression continues in the epidermis (but not in the
developing central nervous system) until it fades during the later larval stages.
Copyright 1998 Elsevier Science Ireland Ltd. All Rights Reserved
PMID- 9767166
TI - Immunohistochemical demonstration of serotonin-containing axons in the
hypothalamus of the white-footed mouse, Peromyscus leucopus.
AB - The wild white-footed mouse, Peromyscus leucopus, is commonly used for
photoperiod studies utilizing physiological, behavioral, and other biological
measures indicative of hypothalamic functions. Indoleamines, like melatonin and
serotonin, are implicated in regulating these hypothalamic functions. Although
neurochemical analyses of hypothalamic serotonin and its receptors have been
reported for this species, the relevant neuroanatomy of the serotonin system
within mouse hypothalamus has not been studied. A sensitive immunohistochemical
method was used to detect serotonin within axons of coronal sections of
formaldehyde fixed forebrain from P. leucopus. Large, medium and small diameter
serotonin axons were evaluated in most regions, or nuclei, of the hypothalamus
rostral to the mammillary region. A fourth type of serotonin axon was observed to
have morphology characteristic of terminal arbors. The density of serotonin axons
ranged from no staining to very high density similar to other species for which
reports exist, i.e., rat, cat, and monkey. The ventromedial hypothalamic nucleus
had distinctively lesser density of serotonin axons in this mouse than other
species. Evidence of terminal arborization in hypothalamic nuclei and regions was
evident. Neuroendocrine, autonomic, and behavioral functions of the hypothalamus
are suggested to be regulated by input from serotonin terminals in this wild
species of mouse, in correlation with receptor localization as reported by
others.
PMID- 9767168
TI - Involvement of the parafascicular nucleus in the facilitative effect of
intracranial self-stimulation on active avoidance in rats.
AB - To evaluate whether parafascicular nucleus (PF) is involved in the facilitative
effect of lateral hypothalamic intracranial self-stimulation (LH-ICSS) on two-way
active avoidance acquisition (5 sessions, 10 trials each, one daily) and long
term retention (10 days), rats were lesioned bilaterally at the PF and implanted
with an electrode aimed at the LH to obtain ICSS behavior. After each acquisition
session rats were allowed to self-administer 2500 trains of LH-ICSS. The main
results were: (1) LH-ICSS facilitated the acquisition and retention of
conditioning; (2) PF lesions impaired both acquisition and retention of two-way
active avoidance; (3) there was a positive relationship between PF lesions size
and learning disruption, and (4) LH-ICSS failed to facilitate learning when PF
was lesioned. We concluded that the lesion size is a critical variable to
evaluate the effects of PF lesions on learning and memory, and that LH-ICSS
treatment may exert their effects through the PF nucleus or, at least, the
integrity of PF is required for LH-ICSS to improve clearly the task.
PMID- 9767169
TI - Role of the cerebellum in exploration behavior.
AB - Compared to +/+ mice, Lurcher (+/Lc) mutant mice whose cerebellar cortex is
lacking almost all Purkinje cells and granule cells, exhibit a low level of
exploration; this deficit is not due to a low level of activity but to both a
decreased motivation to explore a novel environment and to spatial deficits. The
characteristics of exploration in cerebellectomized +/+ and +/Lc mice suggest
that the cerebellum is involved not only in cognitive but also in motivational
processes.
PMID- 9767170
TI - Renal sympathetic nerve activity in mice: comparison between mice and rats and
between normal and endothelin-1 deficient mice.
AB - Recently generated knockout mice with disrupted genes encoding endothelin (ET)-1
showed an elevation of arterial blood pressure (AP) and supplied an evidence for
intrinsic ET-1 as one of the physiological regulators of systemic AP. Little is
yet known, however, why deficiency of ET-1, which was originally found as a
potent vasoconstrictor, led to higher AP in these mice. To address this apparent
paradox, we first developed a method to measure renal sympathetic nerve activity
(RSNA) in mice using rats as reference and successively compared it between
normal and ET-1 deficient mice. RSNA was successfully recorded in urethane
anesthetized and artificially ventilated mice by a slight modification of the
method used for rats. At basal condition, mean AP (MAP) and RSNA in ET-1
deficient mice (105+/-2 mmHg and 9.71+/-1.49 muVs, n=20) were significantly
higher than those in wild-type mice (96+/-2 mmHg and 5. 07+/-0.70 muVs, n=25).
Basal heart rate (HR) and baroreflex-control of HR was not significantly
different between the two. On the other hand, resting RSNA, RSNA range, and
maximum RSNA were significantly greater in ET-1 deficient mice, and thus MAP-RSNA
relationship was upwards reset. Hypoxia-induced increase in RSNA was not
different between ET-1 deficient (73.4+/-9.4%) and wild-type mice (91.2+/-12.0%),
while hypercapnia-induced one was significantly attenuated in ET-1 deficient mice
(18.8+/-3.6 vs. 39.1+/-5.2% at 10% CO2). These results indicate that endogenous
ET-1 participates in the central chemoreception of CO2 and reflex control of the
RSNA. Baroreceptor resetting and normally preserved hypoxia-induced chemoreflex
may explain a part of the elevation of AP in ET-1 deficient mice.
PMID- 9767171
TI - Temporospatial characteristics of light-induced fos immunoreactivity in
suprachiasmatic nuclei are not modified in Syrian hamsters treated neonatally
with monosodium glutamate.
AB - Neonatal treatment of rodents by intraperitoneal injections of monosodium
glutamate (MSG) destroys many retinal ganglion cells whose neurons belong to the
circadian system; howertheless, adults always synchronize their locomotor
activity rhythm (LAR) to the light/dark cycle. Recent studies have shown that
light-induced phase shifts of LAR are associated with the c-fos induction in
suprachiasmatic nuclei (SCN) of nocturnal rodents. In this study, the circadian
system was analyzed in treated and control hamsters maintained in constant
darkness and exposed to light at circadian times (CTs) 13 and 18 during
subjective night, 1 and 6 h after the onset of LAR. The period of the LAR and
delay (CT13) and advance (CT18) phase shifts of LAR were not significantly
different between MSG-treated and control hamsters. Temporospatial variations of
Fos induction after light exposure were similar in both MSG-treated and control
hamsters although the total number of Fos immunoreactive (Fos-ir) nuclei in the
SCN was always lower in treated hamsters. However, the decrease in Fos-ir was
significant only for the caudal third of the SCN of treated hamsters, the part
where retinal afferents are most dense. The effect of light exposure on Fos
expression in SCN of MSG-treated and control hamsters was the same at CT13 and
CT18: (1) Fos-ir nuclei were significantly more numerous at CT18 than at CT13 in
the rostral SCN; (2) dorsal Fos-ir cells were observed in the SCN only at CT18;
(3) a ventral subgroup expressed Fos protein in intermediate SCN only at CT13.
This study demonstrates that MSG-treatment does not significantly modify the
phase-shifting effects of light on either the LAR or the associated cellular
activation.
PMID- 9767172
TI - Localization of glutathione and induction of glutathione synthesis-related
proteins in mouse brain by low doses of gamma-rays.
AB - First, we determined the cerebral localization of reduced glutathione (GSH) in
normal mice by means of autoradiography using 99mTc-meso-hexamethyl propylene
oxime. A highly specific localization of GSH in the cerebellum and hippocampus
was observed. Secondly, we measured the elevation of GSH level in the brain after
low-dose gamma-irradiation. The cerebral GSH levels increased soon after
irradiation with 50 cGy of gamma-rays, reaching a maximum at 3 h post-treatment,
then remaining significantly higher than that of the non-irradiated control until
12 h and returning to the control level by 24 h. Thirdly, we examined the
induction of the activities and the mRNAs of proteins involved in the synthesis
and regeneration of GSH in the brain of mice subjected to low-dose gamma-ray
irradiation. The level of mRNA for gamma-glutamylcysteine synthetase was
significantly increased at 0.5 h, and remained high until 2 h post-irradiation
(50 cGy). The level was transiently lowered to the non-irradiated control level
at 3 h and slightly increased again after 6 h post-irradiation. gamma
Glutamylcysteine synthetase activity was significantly increased 3 h after
irradiation, and remained high up to 24 h post-irradiation. As for glutathione
reductase, the mRNA level was increased at 0.5 h, and peaked strongly at 2 h,
while the enzyme activity was significantly increased at 6 h after irradiation,
and continued to increase up to 24 h. The level of mRNA for thioredoxin, which
contributes to GSH biosynthesis by supplying cysteine to the de novo pathway,
peaked between 0.5 h and 2 h post-irradiation, and rapidly declined thereafter.
The content of thioredoxin showed a transient decrease immediately after
irradiation, but was then remarkably elevated, reaching a maximum at 3 h, and
thereafter declining sharply. These results indicate that the increase in
endogenous GSH in mouse brain soon after low-dose gamma-ray irradiation is a
consequence of the induction of GSH synthesis-related proteins and occurs via
both the de novo synthesis and the regeneration pathways.
PMID- 9767173
TI - Effects of brain endogenous insulin on neurofilament and MAPK in fetal rat neuron
cell cultures.
AB - We demonstrated the 'de novo' synthesis of insulin within the fetal nervous
system in vivo and in vitro. We undertook this study to show a role for brain
endogenous insulin within the fetal brain. We used neuron cell cultures (NCC)
from 19 days gestational age fetal rat brains incubated in an insulin free/serum
free defined medium. The neurons showed the presence of preproinsulin I and II
mRNA using polymerase chain reaction and insulin immunoreaction employing
peroxidase anti-peroxidase and radioimmunoassay techniques. Using an anti-pan
neurofilament antibody (that recognizes non-phosphorylated neurofilaments)
neurofilament immunoreaction (NFI) was observed within the neuron body, dendrites
and axon. Either insulin antibody or isoproterenol treatment induced the neurites
to retract and most of the neurons become round, with NFI confined to the neuron
body. The antibody treatments induced the neurons to become hypertrophic and
vacuolated. With PD98059 treatment NFI was only observed within the neuron body.
The addition of insulin reversed the effects of isoproterenol and PD98059, but
not those of the insulin antibody. Treatment with wortmannin had no effect.
Western blot analysis showed that the basal level of mitogen activated protein
kinase (MAPK) phosphorylation was inhibited by the treatment of the NCC with
isoproterenol or trypsin, but was significantly increased by treatment with
exogenous insulin, demonstrating that brain endogenous insulin phosphorylated
MAPK (p<0.05). Thus, brain endogenous insulin promotes neurite outgrowth,
probably via MAPK and by stimulating neurofilament distribution via this
mechanism participates in neuron differentiation.
PMID- 9767175
TI - Neurocalcin-immunopositive nerve terminals in the muscle spindle, Golgi tendon
organ and motor endplate.
AB - The present study revealed the immunohistochemical distribution of neurocalcin, a
three EF-hand calcium-binding protein, in the rat muscles and tendons. In the
muscle spindles, annulospiral endings, which made spirals around the intrafusal
muscles, showed intense neurocalcin-immunoreactivity. In the Golgi tendon organs,
immunopositive thick nerve fibers entered the collagenous fibers resulting in the
projection of many swelling terminals. In all examined muscles, nerve terminals
in the motor endplates showed neurocalcin-immunoreactivity associated with the
membranes of synaptic vesicles and mitochondria. These findings suggest that
neurocalcin is distributed and regulates calcium signaling in both afferent and
efferent nerve terminals in the muscles and tendons.
PMID- 9767174
TI - Spinal inputs from lateral columns to reticulospinal neurons in lampreys.
AB - This study characterizes the inputs from the lateral columns of the spinal cord
to reticulospinal neurons in the lampreys, using the in vitro isolated brainstem
and spinal cord preparation. Synaptic responses to the electrical stimulation of
the lateral columns were recorded in reticulospinal neurons of the posterior and
middle rhombencephalic reticular nuclei. The responses consisted of a mixture of
excitation and inhibition. They were markedly potentiated when using trains of
two to five pulses, suggesting that the larger part of these synaptic responses
was mediated via an oligosynaptic pathway. An early component, however, persisted
when using twin pulses at 10-20 Hz on the ipsilateral side, suggesting the
presence of an early mono- or disynaptic component. When increasing the
stimulation strength, an early fast rising excitatory component appeared. It most
likely resulted from an antidromic activation of vestibulospinal axons in the
lateral tracts, which make en passant synaptic contacts with reticulospinal
neurons. Responses were practically abolished by adding CNQX and AP5 to the
Ringer's solution. The late component of excitatory responses was decreased by
AP5, suggesting that NMDA receptors were activated. The NMDA receptor-mediated
component was larger when using trains of stimuli or in Mg2+-free Ringer's. The
application of NMDA depolarized reticulospinal neurons. The glycinergic
inhibitory component was markedly increased in Mg2+-free Ringer's. Moreover,
GABAB-receptor activation with (-)-baclofen abolished both excitatory and
inhibitory responses. Taken together, the present results indicate that ascending
lateral column axons generate large excitatory and inhibitory synaptic potentials
in reticulospinal neurons. The possible role of these inputs in modulating the
activity of reticulospinal neurons during locomotion is discussed.
PMID- 9767176
TI - Sigmoidal compression rate-dependence of inert gas narcotic potency in rats:
implication for lipid vs. protein theories of inert gas action in the central
nervous system.
AB - Inert gases at raised pressure exert anaesthetic effects. It is assumed that
anaesthesia by the inert gases is fundamentally similar to anaesthesia produced
by general anaesthetics. However, do general anaesthetics bind directly to
proteins or influence activity by indirectly perturbing membrane lipids still
remains a major question. Although the pressure required to achieve anaesthesia
with inert gases has been suggested to exert potentially some pressure antagonism
per se, this has not been studied yet to our knowledge. We investigated this
possibility using nitrogen, argon, and nitrous oxide. Whatever the narcotic agent
used, our results showed that the pressure of narcotic required to induce
anaesthetic effects increased, as compression rate increased, in a sigmoid
fashion rather than in a linear fashion. Evidence for sigmoidal responses vs.
linear responses depended of the narcotic potency of the anaesthetic agent used
(nitrogen: r2=0.973 vs. r2=0.941; argon: r2=0. 971 vs. r2=0.866; nitrous oxide:
r2=0.995 vs. r2=0.879). Since a linear antagonism is predicted by lipid theories,
we think it likely that these findings indicate that inert gases bind to a
modulatory site of a protein receptor and act as allosteric modulators. Since
other workers provided evidence for binding processes using volatile
anaesthetics, the present findings could indicate that all classes of general
anaesthetics, including inert gases, could act by binding directly to proteins
rather than by dissolving in some lipids of the cellular membrane.
PMID- 9767177
TI - Glucocorticoids interact with gp120 in causing neurotoxicity in striatal
cultures.
AB - A significant subset of HIV-positive patients suffer from AIDS-Related Dementia
Complex (ADC), an array of neurologic and neuropsychologic impairments. The HIV
coat protein gp120 has been implicated in the deleterious neurologic consequences
of HIV infection, damaging neurons through a glutamatergic and calcium-dependent
pathway. We have previously reported that glucocorticoids, the adrenal steroids
secreted during stress, can exacerbate the neurotoxic and calcium-mobilizing
effects of gp120 in hippocampal and cortical cultures. Because both the
symptomatology of ADC, as well as the neuropathologic profile of post-mortem HIV
brains suggests an involvement of the striatum, we examined whether
glucocorticoids could also augment the damaging effects of gp120 in primary
striatal cultures. We observe that neither gp120 nor the glucocorticoid
corticosterone, when administered alone, cause neurotoxicity or mobilization of
free cytosolic calcium; however, a combination of the two caused significant
toxicity and neuron death. This, along with our prior findings of gp120
glucocorticoid interactions, is striking, given the heavy clinical use of
synthetic glucocorticoids for management of pulmonary complications of HIV
infection.
PMID- 9767178
TI - Diurnal rhythm in cyclic GMP/nitric oxide efflux in the medial preoptic area of
male rats.
AB - Since nitric oxide (NO) is implicated in the neuroendocrine control of
luteinizing hormone-releasing hormone (LHRH) secretion and sexual behavior which
show diurnal variations, we monitored cGMP levels (an index of NO activity) in
the extracellular compartment of the medial preoptic area (MPOA) using
microdialysis. It was observed that MPOA cGMP levels rose significantly in the
afternoon in both castrated and intact male rats, thereby suggesting the
existence of a diurnal rhythm in MPOA cGMP/NO efflux which may participate in
eliciting the well-known diurnal variations in LHRH neuronal activity and male
sexual behavior.
PMID- 9767179
TI - Consecutive in vivo measurement of nitric oxide in transient forebrain ischemic
rat under normothermia and hypothermia.
AB - The effects of hypothermia on production of nitric oxide (NO) in ischemic brain
were investigated by using in vivo microdialysis. Male Wistar rats were randomly
divided into three groups; saline-treated normothermic group (37 degreesC, n=6),
30 mg/kg N-nitro-l-arginine methyl ester(l-NAME)-treated normothermic group
(n=6), and saline-treated hypothermic group (30 degreesC, n=6). Transient
forebrain ischemia was produced by bilateral common carotid artery occlusion
combined with hypotension (MABP=50 mmHg). Saline-treated normothermic animals
resulted in a reduction of LCBF to 9% of baseline. Saline-treated hypothermic
rats revealed the similar changes of LCBF. In contrast, l-NAME administration
reduced the basal CBF to 85% of saline-treated group and to 8% after ischemia. NO
products were decreased during ischemia and transiently increased after
reperfusion in saline-treated groups. However, the increase of NO products after
reperfusion was less significant in the hypothermia. l-NAME-treated group showed
a constant reduction of NO production during ischemia and after reperfusion.
PMID- 9767180
TI - Reduced glucose-induced neuronal activation in the hypothalamus of diet-induced
obese rats.
AB - Rats predisposed to develop diet-induced obesity (DIO) preferentially activate
their sympathetic nervous system during intracarotid glucose infusion [B.E.
Levin, Intracarotid glucose-induced norepinephrine response and the development
of diet-induced obesity, Int. J. Obesity 16 (1992) 451-457.] but their brains are
generally less responsive to glucose than diet-resistant rats (DR) [B.E. Levin,
K.L. Brown, A.A. Dunn-Meynell, Differential effects of diet and obesity on high
and low affinity sulfonylurea binding sites in the rat brain, Brain Res. 739
(1996) 293-300.; B.E. Levin, B. Planas, Defective glucoregulation of brain alpha2
adrenoceptors in obesity-prone rats, Am. J. Physiol. 264 (1993) R305-R311.; B.E.
Levin, A.C. Sullivan, Glucose-induced norepinephrine levels and obesity
resistance, Am. J. Physiol. 253 (1987) R475-R481.; B.E. Levin, A.C. Sullivan,
Glucose-induced sympathetic activation in obesity-prone and resistant rats, Int.
J. Obesity 13 (1989) 235-246.]. Here, 1 h intracarotid glucose infusions (4
mg/kg/min) selectively increased Fos-like immunoreactivity (FLIR) in the
hypothalamic paraventricular, ventromedial, dorsomedial and arcuate nuclei of
inbred DR but not DIO rats. This suggests that enhanced glucose-induced
sympathetic activation in DIO rats is related to a failure of glucose to produce
neuronal activation in these areas.
PMID- 9767181
TI - An increase in [3H] CGS21680 binding in the striatum of postmortem brains of
chronic schizophrenics.
AB - We measured adenosine 2a receptors in basal ganglia of 13 schizophrenics and 10
controls, using [3H] CGS21680 as a ligand for the receptor binding assay. There
was a significant increase in the specific [3H] CGS21680 binding in the putamen
and caudate, but not in the globus pallidus of externa, of the schizophrenic
patients, compared to those of controls. These results provide evidence
suggesting that adenosine 2a receptors play a role in the pathophysiology of
schizophrenia.
PMID- 9767182
TI - Inducers of the cytochrome P-450 superfamily as promoters of carcinogenesis.
AB - This review summarizes data on the mechanisms of tumor-promoting activity of non
genotoxic compounds that are inducers of cytochrome P-450 isoforms. Their
promoting activity is analyzed in term of synthesis of new cytochrome P-450
isoforms. Active oxygen species formed by cytochrome P-450 isoforms can
simultaneously act as stimulators of proliferation and inhibitors of
intercellular communications. Promoter effects can be associated with changes in
the ratio of cellular signaling non-protein molecules induced by newly
synthesized cytochrome P-450 isoforms. Data on induction of cytochrome P-450
isoforms of family 1 indicate that inducer interaction with its receptor causes
cellular events resulting in the stimulation of cell proliferation.
PMID- 9767183
TI - Extracellular proteolytic enzymes of filamentous fungi.
AB - This review involves generalized data on extracellular proteases of filamentous
fungi. General characteristics of secreted proteases and their classification are
considered. Analysis of the data available revealed that fungi secrete only
serine, aspartyl, and metalloproteases. Nothing is known about secretion of
cysteine proteases; some available data do not have clear experimental evidence.
Physicochemical and kinetic properties of the most typical extracellular
proteases of different classes and families are discussed in detail. Special
attention is focused in the review on regulation of synthesis of extracellular
proteases and participation of the secreted proteases of pathogenic fungi in the
infection process in animals, insects, or plants.
PMID- 9767184
TI - Photoaffinity labeling of DNA polymerase from Thermus thermophilus and DNA
template by photoreactive analogs of dCTP.
AB - Substrate properties of dCTP analogs N4-[2-(4-azidotetrafluorobenzoylamino)
ethyl]-2;-deoxycytidine-5; -triphosphate (FABdCTP), 5-[N-(4
azidotetrafluorobenzoyl)-3-amino-trans-propen-1-yl] -2;-deoxycytidine-5;
triphosphate (AlFABdCTP), and N4-[2-(2-nitro-5-azidobenzoylamino)-ethyl]-2;
deoxycytidine-5; -triphosphate (NABdCTP) were studied in the reaction of DNA
synthesis catalyzed by DNA polymerase from the extremely thermophilic bacterium
Thermus thermophilus B 35 (Tte DNA polymerase). The enzyme was photoaffinity
labeled with the mentioned derivatives, NABdCTP being used for the first time.
The photoreactive primers containing FABdCTP and AlFABdCTP were synthesized in
situ by Tte DNA polymerase and used in the complementary addressed labeling of
DNA template. The efficiency of DNA template labeling is shown to be a function
of the structure of the photoactive group.
PMID- 9767185
TI - Human breast milk immunoglobulins G hydrolyze nucleotides.
AB - Catalytically active antibodies, abzymes, appear in the blood of mammals
immunized with the analogs of transition state or in the case of autoimmune
diseases. Until recently, it was not shown whether abzymes exist in the blood of
apparently healthy subjects. We have discovered that secretory IgA (sIgA) from
the milk of healthy mothers catalyze phosphorylation of a variety of proteins and
that IgG can hydrolyze DNA and RNA. In this study for the first time it is shown
that IgG from human milk (and their Fab-fragments) also catalyze hydrolysis of
nucleoside mono-, di-, and triphosphates. The data meet certain stringent
criteria, unambiguously indicating that the observed catalytic activity is
associated with IgG rather than contaminating enzymes. Although the nucleotide
binding site of IgG is located in the light antibody chain, L-chains per se
cannot hydrolyze NTP unlike the DNA-hydrolyzing abzymes. Kinetic and
thermodynamic parameters that characterize the interaction of NTP and dNTP with
IgG-abzymes were analyzed. Possible reasons for appearance of polyclonal abzymes
with different catalytic activities in the milk of healthy mothers are
considered.
PMID- 9767186
TI - Interaction of human milk lactoferrin with ATP.
AB - Human lactoferrin exhibits many unique properties. It is known as one of the most
important factors that provide nonspecific defense of cells against bacteria,
viruses, and carcinogenesis, as well as an important component of a specific
system responsible for the passive immunity of newborns. As a compound with
extremely broad spectrum of functions many of which were not elucidated so far,
lactoferrin is intensely studied. In this study we obtained electrophoretically
and immunologically homogenous preparations of lactoferrin from human milk. Using
various methods, we were the first to show that the fraction of lactoferrin,
which displays an increased affinity for Sepharose Blue, forms complexes with ATP
with a stoichiometry of 1 mole ATP per mole protein. It is shown that the ATP
binding site is located in the C-terminal domain of the lactoferrin molecule. The
binding of ATP results in the dissociation of tetrameric forms of the protein and
a change in the mode of interaction of lactoferrin with polysaccharides and other
proteins. The data may be used in analysis of the possible reasons for
multifunctional properties of lactoferrin and possible ways of regulation of its
functions.
PMID- 9767187
TI - Calorimetric studies of the thermal unfolding of smooth muscle myosin fragments
and their complexes with ADP and phosphate analogs.
AB - The thermal unfolding of turkey gizzard smooth muscle myosin subfragment 1 (S1)
and heavy meromyosin (HMM) in the absence of added nucleotides, in the presence
of ADP, and in S1 or HMM ternary complexes with ADP and Pi analogs, orthovanadate
(Vi), beryllium fluoride (BeFx), or aluminum fluoride (AlF4-), have been studied
by differential scanning calorimetry (DSC). It has been shown that the formation
of these ternary complexes causes significant structural changes in S1 or in the
heads of HMM which are reflected in a pronounced increase of the protein thermal
stability. The effect of BeFx was less distinct than that of AlF4- or Vi.
Phosphorylation of regulatory light chains (RLC) in S1 or in HMM had practically
no influence on these effects. In general, the changes caused by various Pi
analogs in smooth muscle S1 or HMM were similar to those observed earlier with
skeletal muscle S1 devoid of RLC. It is concluded that RLC and their
phosphorylation do not significantly affect the character of structural changes
induced in motor domains of the HMM heads by the formation of ternary complexes
HMM--ADP--Vi, HMM--ADP--AlF4-, and HMM--ADP--BeFx--stable analogs of the
intermediate states of the HMM ATPase reaction, HMM.ADP.Pi and HMM. ATP.
PMID- 9767188
TI - Structure of the decoding center of the ribosome.
AB - The decoding center of the ribosome provides mRNA translation and the fidelity of
the codon--anticodon interactions along with mRNA translocation in the course of
protein biosynthesis. The three-dimensional structure of the ribosome decoding
center is still unknown. However, up to now a number of direct and indirect
experimental data on the structural and functional organization of the decoding
center have been obtained. In this paper the main components of the decoding
center are described on the basis of our own experimental results combined with
data from the literature. A model of their spatial arrangement at the small
ribosomal subunit is suggested.
PMID- 9767189
TI - Radiation-induced lipoperoxidative stress in children coupled with deficit of
essential antioxidants.
AB - Catabolic products of the lipoperoxidative cascade (LPC), including diene
conjugates, ketodienes, and carbonyl compounds, as well as essential lipid
bioantioxidants (BAO)--vitamins E and A--were determined in blood plasma of 428
children aged 0-7 years residents of areas contaminated with radionuclides after
the Chernobyl Power Plant accident. Individual external gamma-irradiation doses
(D) were determined. Gamma-irradiation accounted for more than 90% of total
radiation loads and correlated with irradiation from absorbed sources in
residents of the areas examined. Before examination, oral multivitamin therapy
(with preparations containing the BAO determined in this work) was administered
to a group of children (group I, n = 90) comparable to the group receiving no
therapy (group II). Group II had two to six times higher mean levels of all LPC
catabolic products and two to three times lower levels of vitamins E and A in
comparison to age-matched subgroups of group I. In group II, individual shifts in
the levels of all catabolic products achieved pathogenic stressor magnitudes at
maximal regional radiation loads. Antenatal exposure and exposure over the first
year of life caused the strongest pathogenic effects. BAO therapy strongly
normalized the levels of LPC and vitamins (E and A) at all doses (up to 7 cSv)
and increased the radiation resistance of the subjects. A total of 47 linear
correlations were found at a p < 0.05 level (r = 0.4 to 0.7 for 54% and p < 0.02
for 87% of equations) between low radiation doses and the extent of deviation of
all metabolites studied from their normal levels. The multiplicity of radiation
dose--effect correlations found under various conditions suggest that
pathological signs found in the children examined were due to irradiation. LPC
system disorders developed at low doses and displayed no threshold effect. The
data suggest that these disorders resulted from free-radical chain-branched LPC
reactions caused by chronic exposure to low doses of strongly ionizing radiation
under conditions of BAO deficiency.
PMID- 9767190
TI - Kinetic investigation of cooperativity in coenzyme binding by transketolase
active sites.
AB - The two-step mechanism of coenzyme (thiamine diphosphate, ThDP) binding with two
initially identical active sites of apotransketolase has been examined with a
kinetic model. Cooperativity between sites in the primary ThDP binding and in the
following conformational transition has been analyzed. The only reliable
difference between sites is shown to be the tenfold difference in the backward
rate constants of the conformational transition; this means that the cooperative
interaction between sites takes place only after termination of both steps of
ThDP binding in both sites.
PMID- 9767192
TI - Kinetics of all stages of electron transfer in nitrogenase in the presence of a
photodonor.
AB - A photodonor is considered as an alternative electron donor for nitrogenase. The
kinetic mechanism of nitrogenase turnover is discussed. The turnover is initiated
by the transfer of an electron to the enzyme and results in formation of a
substrate molecule. The effective rate constant of concerted transfer of the
first and the second electron from Av2 (Fe-protein) to Av1 (Mo-Fe-protein) and
the rate constant of transfer of the second electron are 70 +/- 7 and 116 +/- 10
sec-1, respectively. The rate constant of the rate-limiting reaction--MgADP
release during formation of the superreduced state of Av1 (*Av12-)--is 12 +/- 2
sec-1. Nitrogenase (E) states in complex E.N2 on binding and reduction of
nitrogen are: E2, E4, E6 (2, 4, and 6 electrons).
PMID- 9767191
TI - Xanthene dyes as photochemical donors for the nitrogenase reaction.
AB - The ability of xanthene dyes to mediate photoinduced reduction of nitrogenase was
tested. In addition to eosin, which was studied in the preceding work
(Biochemistry (Moscow), 1996, 61, 2165-2172), 4', 5'-dibromofluorescein (DBF),
cyanosine, and erythrosin are effective photodonors of an electron in the
presence of NADH. Fluorescein, rhodamine B, rhodamine 6G, and porphyrins are
unable to mediate photoinduced reduction of nitrogenase. The mechanism underlying
different efficiency of xanthene dyes in this reaction was studied. At high
concentrations, all xanthene dyes tested were shown to inhibit the intramolecular
electron transfer in nitrogenase. The inhibiting concentration of DBF is 1.5.10-4
M, whereas for other dyes, the inhibiting concentrations are less than 1.5.10-4
M. Under otherwise identical conditions, the ATPase activity was inhibited by
xanthene dyes to a lesser extent than the nitrogenase activity. DBF, the most
effective photodonor, was also studied by differential kinetic pulse laser
spectroscopy. Photoinduced reduction of nitrogenase, (Fe-proteinox.Mo-Fe
protein).MgATP or (Av2ox.Av1).MgATP, was studied within the time range from 0 to
100 msec. Two initial stages of the nitrogenase turnover were detected:
photoinduced reduction of Av2 and electron transfer from Av2red to Av1. The
kinetics of the photoinduced reduction of Av2.MgADP was studied in the presence
of DBF (up to 1.3.10-4 M) both in solution and the complex with Av1. The apparent
second-order rate constants of the photoinduced reduction of Av2.MgADP in
solution and the complex with Av1 were determined as 9.7.107 +/- 106 and 1.2.108
+/- 1.2.107 M-1. sec-1, respectively. The rate constant of the second reaction in
the presence of another donor (dithionite) is 2500 times less. In complexes with
Av1, the photochemical donor system DBF--NADH reduces Av2 more effectively than
in free state in solution. In the presence of the photochemical donor system,
neither photoreduction of Av2 in complexes with Av1 nor electron transfer from
Av2red to Av1 are the rate-limiting stages of nitrogenase turnover.
PMID- 9767193
TI - One year after CAPRIE, IST and ESPS 2. Any changes in concepts?
AB - The IST, CAPRIE and ESPS-2 have shown that large collaborative randomised trials
can be conducted in stroke medicine and can provide statistically and clinically
significant results. They, and other concurrent studies, have highlighted the
potential hazards of early anticoagulation, and the effectiveness and safety of
early (and continuous) antiplatelet therapy in limiting early stroke recurrence
and its consequences. In addition, they have shown that antiplatelet agents with
differing mechanisms of action can have different effects, and perhaps additive
effects when combined. The ESPRIT trial should delineate the roles of oral
anticoagulant therapy, and the combination of aspirin and dipyridamole, in the
prevention of stroke due to arterial disease. Future trials will hopefully
determine the role in secondary stroke prevention of inhibitors of the platelet
GPIIb/IIIa complex (the final common pathway of platelet aggregation), the
combination of anitplatelet agents with different mechanisms of action (e.g.
aspirin and clopidogrel, aspirin and IIb/IIIa inhibitors), the combination of
antiplatelet agents and oral anticoagulants (which may simultaneously modify
platelet function and fibrin production), and the combination of antithrombotic
and cholesterol-lowering (statin) medications.
PMID- 9767194
TI - Therapeutic inhibition of platelet function in stroke.
AB - Platelet-dependent thrombotic- and thromboembolic-occlusive events are the usual
cause of ischemic strokes. Antiplatelet strategies target one of the three
platelet recruitment pathways (thromboxane A2, adenosine diphosphate, or
thrombin) or the common cohesion pathway involving integrin alphaIIbbeta3
fibrinogen receptors. Aspirin selectively and irreversibly interrupts TxA2 and
decreases events by 20-25%. Clopidogrel selectively and irreversibly inactivates
platelet-ADP receptors and reduces events by 30-35%. Additive effects are
produced by combining aspirin and clopidogrel. Integrin alphaIIbbeta3 fibrinogen
receptor antagonists, such as abciximab, produce dose-dependent inhibition of
platelet recruitment and thrombo-occlusive events, regardless of the agonist(s)
initiating platelet activation, but correspondingly impair platelet hemostatic
function. Because chronic antiplatelet therapy has the potential for producing
abnormal bleeding it is important for current clinical trials to evaluate the
benefit risk relationship.
PMID- 9767195
TI - Antithrombotic drugs: insights from cardiology.
AB - The primary purpose of this overview is to provide an update on the newer
antiplatelet drugs evaluated in clinical trials and introduced in clinical
practice of modern cardiology. Despite the remarkable clinical developments with
the use of new antiplatelet drugs, several fundamental issues remain unresolved.
Some of the observed safety/efficacy problems in major clinical trials can be
directly attributed to the lack of careful phase II studies where issues such as
monitoring, pharmacological profiles, and individual response variations were not
considered sufficiently. Nevertheless, none of the available antiplatelet agents
meet all the criteria of an ideal antiplatelet agent. Aspirin has been the
standard reference agent in cardiovascular disease. However, it is a weak and
nonselective antiplatelet compound and is unable to interfere substantially with
the thrombogenic activity of a fresh mural thrombus of a stenosed vessel. The
newer antiplatelet drug classes such as the ADP receptor blockers (ticlopidine,
clopidogrel) and the platelet glycoprotein IIb/IIIa receptor inhibitors produce
their therapeutic effects by distinct mechanisms which differ from aspirin. Large
clinical trials have documented their efficacy in acute coronary syndromes
associated with intracoronary thrombus formation. The future challenge is to
evaluate long-term treatment strategies which are equally safe but distinctly
more effective than aspirin, e.g. a combination therapy with aspirin and
clopidogrel or oral GP IIb/IIIa receptor antagonists.
PMID- 9767196
TI - New genetic concepts and stroke prevention.
AB - So far, stroke genetics has the reputation of daunting complexity and
heterogeneity. However, progress through efforts at studying the human genome has
provided novel technologies and focus, and 12 stroke genes or loci have already
been identified in the last years, usually through the study of large pedigrees.
However, particularly little is known about the ischemic form of stroke, and only
recently could one chromosomal locus be shown to exert a major effect on stroke
latency and outcome - through QTL studies in mouse strains. Whether the
outstanding role of this one gene locus is also true in humans should be tested
in linkage analyses of large pedigrees. The characterization of such families
will probably be essential for progress in molecular genetics of ischemic stroke
as well as being a challenge for clinical stroke centers.
PMID- 9767198
TI - Introduction
PMID- 9767197
TI - New concepts for drug therapy after stroke. Can we enhance recovery?
AB - Neurologic functions improve in most patients days and weeks after onset of a
stroke. This can not be explained by recovery of the early salvageable ischemia
zone. The most likely mechanism is relearning, a process in which healthy brain
takes over functions lost with the infarct. Experimental studies indicate that
this recovery can be modulated by pharmacological agents. NMDA antagonists and
GABA agonists found to reduce infarct size in stroke models may have a harmful
effect on relearning and neurologic recovery. This should be considered when
clinical trial protocols are designed.
PMID- 9767199
TI - Comparison of buprenorphine and methadone maintenance in opiate addicts.
AB - As a maintenance agent for opioid dependency, buprenorphine offers advantages
such as a lower level of dependence and minimal withdrawal symptoms, due to its
partial agonist properties at the micro-opioid receptor. Previous studies have
shown 8 mg sublingual buprenorphine to be equivalent to 60 mg oral methadone in
terms of retention rate and opioid-negative urine levels. In a 24-week, ongoing
European study, 34 opioid-dependent subjects were assessed; 16 receiving
buprenorphine and 18 methadone. A free dosing schedule was used with no upper
limit for methadone dosing but with a maximum buprenorphine dose of 8 mg.
Screening prior to the study excluded subjects with polysubstance dependence,
somatic disease and/or HIV infection. Primary outcome measures were abstinence
from other drugs, for which subjects provided weekly urine samples for analysis
of opioids, cocaine and benzodiazepines, and retention in treatment. Patients in
the buprenorphine group provided a greater proportion of negative urine samples,
in particular cocaine-negative samples, compared with the methadone group,
although this was not statistically significant. Retention in the buprenorphine
group was significantly lower than in the methadone group, suggesting that the 8
mg buprenorphine limit may have biased the results in favour of methadone, and
that this dose may have been too low for those subjects with high levels of
dependence. However, buprenorphine is clearly effective in the more motivated
subjects and further investigation in this subgroup is recommended.
PMID- 9767200
TI - Substitution with buprenorphine in methadone- and morphine sulfate-dependent
patients. Preliminary results.
AB - In France, during the 1990s, there have been some rapid developments in the
treatment of opioid addiction with the introduction of legal substitution agents.
Originally, some patients were treated with morphine sulfate, but this was
superseded by high dose buprenorphine (Subutex(R)) and methadone. This resulted
in those patients originally treated with morphine being transferred to either of
these two licensed products. A study investigating the effects of the transition
from morphine to either buprenorphine or methadone was undertaken. Supplementary
to this, a trial investigating transition between these new compounds was also
conducted. The primary outcome measures for these trials were retention rate,
which was assessed at 5, 9 and 12 months, and the precipitation of withdrawal
symptoms. The studies showed that transferring patients between substitution
agents can be accomplished without severe withdrawal symptoms, although specific
management may be required for transfer from high doses of methadone to
buprenorphine. High long-term retention rates were observed in the studies, with
most drop-outs occurring directly after transfer. Results suggest that patients
on long-term buprenorphine maintenance therapy may have good compliance in
comparison with other agents.
PMID- 9767201
TI - Comparison of buprenorphine and methadone in the treatment of opioid dependence.
Swiss multicentre study.
AB - A three-centre, randomised, double-blind study was designed to compare the
efficacy and safety of buprenorphine and methadone. This was the first European
study to compare these agents and was based on a previous trial performed in the
US. Opioid-dependent subjects were randomised to receive either sublingual
buprenorphine or oral methadone daily. Both objective and subjective measures of
efficacy were monitored weekly, and safety parameters were regularly monitored
over the entire six-week study. Urinalysis showed that the two treatments were
similar with a slight increase in opioid-negative urines noted in both groups.
The retention rate in the buprenorphine group was lower than in the methadone
group, although it has been suggested that the buprenorphine dose may have been
too low for some patients. None of the side effects noted were considered serious
and all were attributable to chronic opioid dependence. Experience of two years
substitution treatment in Fribourg suggests that initial induction onto
buprenorphine allows for patients to be subgrouped before being given the most
appropriate maintenance agent. Further investigation is required into the
different dose-related effects of buprenorphine seen in particular subsets of
addicts.
PMID- 9767202
TI - The French experience--the pharmacist, general practitioner and patient
perspective.
AB - High-dose buprenorphine (Subutex(R)) has been available in France as a
maintenance treatment since February 1996. Results from a twice yearly survey of
pharmacists, general practitioners (GPs) and patients themselves in the use of
Subutex(R) appeared to be representative of the general substitution therapy
situation in France. Results from May 1997 were encouraging, with improved
relationships between pharmacists and patients, and GPs and patients being
reported in all three surveys. The most commonly prescribed dosage of
buprenorphine (6-8 mg) was within the recommended range, although there was
evidence that this was usually taken as several daily intakes by the majority of
addicts. Although intravenous injection may occur in some cases, illicit resale
was suspected only in a few cases. Treatment efficacy was high and retention at
six months was good since patients had a positive opinion of their treatment and
reported few adverse effects. Further improvement in the relationships between
GPs and pharmacists is desirable to increase the success of the treatment
programme.
PMID- 9767203
TI - Differences between general practitioner- and addiction centre-prescribed
buprenorphine substitution therapy in France. Preliminary results.
AB - The treatment of heroin addiction in France relies on either general
practitioners (GP) or specialist Addiction Centres (ACs). In general, the GPs
offer a more flexible approach regarding frequency of consultations, urine tests
and dosing regimen while the AC approach is more structured. A cohort study was
undertaken to compare the treatment strategies of buprenorphine therapy between
these medical environments. To determine the efficacy of each treatment, a number
of outcomes were measured including the Addiction Severity Index, retention rates
at 90 and 180 days, the average dose prescribed, quality of life assessment, body
weight and two self-reported measures: treatment perception and predictive total
duration. A total of 69 patients were enrolled; 32 treated by GPs and 37 treated
in ACs. Significant differences, including average age, addiction severity and
employment status were apparent between each group. Nevertheless, significant
improvements in the social and medical status were observed in all patients after
3 months, continuing after 6 months in both groups. Treatment retention was good
in both groups with 65% of the total sample remaining after 180 days. The usually
more flexible GP approach was more rigid in this study, resulting in an equally
positive treatment outcome as seen in the ACs. The study highlights the
effectiveness of buprenorphine in addicts with different social and medical
backgrounds, regardless of the therapeutic approach.
PMID- 9767204
TI - Preliminary assessment of a 10-day rapid detoxification programme using high
dosage buprenorphine.
AB - The original French therapeutic strategy for the treatment of opioid addiction
was a rapid detoxification occasionally accompanied by treatment for withdrawal
symptoms. In 1995, substitution therapy using opioids was introduced with the aim
of maintenance, utilising methadone and the partial agonist buprenorphine,
introduced in 1996. As well as being a maintenance agent, buprenorphine has been
prescribed for rapid detoxification due to its reduced tendency to cause any
withdrawal effects and its ability to block the effects of other opioids. This
trial was initiated to measure the efficacy of buprenorphine in rapid
detoxification and to assess whether additional medication would be required.
Participants in this open study had requested rapid detoxification and were
referred to the addiction clinic as inpatients. Patients were assessed by the
clinician and during counselling sessions, and an initial dose was agreed upon.
This dose was then gradually decreased over ten days in a flexible dosing
schedule, with concurrent toxicological urinalysis to ensure no illicit drug use.
During the trial, 25% of patients transferred to a maintenance programme and 58%
remained in the study. The large transfer of patients to maintenance programmes
may indicate that many people requesting rapid detoxification are actually asking
for a more generalised form of assistance. No opioid-positive urines were noted
after the fourth day in any patients, and the study indicates that buprenorphine
should prove to be a useful detoxification agent, particularly in less hardened
addicts. Step-down buprenorphine detoxification minimises withdrawal symptoms
and, therefore, reduces the need for concurrent medication.
PMID- 9767205
TI - Buprenorphine maintenance in pregnant opiate addicts.
AB - Opioid maintenance agents such as methadone and slow-release morphine have
provided beneficial effects in pregnant opioid-dependent women in both themselves
and their child. However, one of the major drawbacks involved with these agents
is that they cause an increase in the severity of neonatal abstinence syndrome
(NAS) when compared to mothers using heroin. Consequently, a trial was performed
to investigate the effects of buprenorphine use during pregnancy. A total of nine
pregnant opioid-dependent women were transferred from either a mean daily dose of
39.7 mg methadone or 400 mg slow-release morphine to a mean daily dose of 8.1 mg
buprenorphine. The buprenorphine-maintained patients were integrated into an
already established outpatient maintenance treatment programme covering all
aspects of prenatal and perinatal care. Results demonstrated that buprenorphine
administration in opioid-dependent pregnant patients is efficacious and well
tolerated. Babies born to buprenorphine-maintained patients had birthweight and
Apgar scores within the normal range (2,500-4,500 g and 9-10, respectively) and
no evidence of opioid-related NAS was observed. The results from this preliminary
study indicate the potential for buprenorphine maintenance therapy in pregnant
addicts, although further research is required to confirm this hypothesis.
PMID- 9767217
TI - Practices that minimize trauma to the genital tract in childbirth: a systematic
review of the literature.
AB - BACKGROUND: Trauma to the genital tract commonly occurs at birth, and can cause
short- and long-term morbidity. Clinical measures to reduce its occurrence have
not been fully identified. METHODS: A systematic review of the English language
literature was conducted to describe the current state of knowledge on reduction
of genital tract trauma before planning a large randomized controlled trial of
ways to prevent such trauma. Randomized trials and other published reports were
identified from relevant databases and hand searches. Studies were reviewed and
assessed using a structured format. RESULTS: A total of 77 papers and chapters
were identified and placed into 5 categories after critical review: 25 randomized
trials, 4 meta-analyses, 4 prospective studies, 36 retrospective studies, and 8
descriptions of practice from textbooks. The available evidence is conclusive in
favor of restricted use of episiotomy. The contribution of maternal
characteristics and attitudes to intact perineum has not been investigated.
Several other topics warrant further study, including maternal position, style of
pushing, and antenatal perineal massage. Strong opinions and sparse data exist
regarding the role of hand maneuvers by the birth attendant for perineal
management and birth of the baby. This became the topic of the planned randomized
controlled trial, which was completed; results will be published soon.
CONCLUSIONS: The case for restricting the use of episiotomy is conclusive.
Several other clinical factors warrant investigation, including the role of hand
maneuvers by the birth attendant in preventing birth trauma. A large randomized
controlled trial will report on this topic.
PMID- 9767218
TI - Postpartum early hospital discharge and follow-up practices in Canada and the
United States.
AB - BACKGROUND: Although official guidelines and recent legislation have addressed
early postpartum hospital discharge and follow-up, little is known about the
practices of obstetricians in Canada and the United States on this issue.
METHODS: Questionnaires were mailed to two separate random samples of 2000
Fellows of the American College of Obstetricians and Gynecologists (ACOG) in the
United States and all Canadian Fellows. Practices and perceptions were compared
with those recommended in the literature, recent legislation, and guidelines of
ACOG and American Academy of Pediatrics (AAP). RESULTS: In contrast to concerns
expressed in the medical literature and official AAP/ACOG guidelines, many
physicians considered potential psychosocial and demographic risk factors
relatively unimportant in making early discharge decisions, preferring to
emphasize aspects of the patient's medical condition, hospital course, and social
support. Although the official guidelines encourage follow-up for all patients
discharged early, additional visits are routinely advised by only 39 percent of
obstetricians after vaginal delivery and by 68 percent after cesarean section.
After vaginal delivery 39 percent of obstetricians used telephone follow-up and
37 percent after cesarean delivery. Moreover, although the official guidelines
recommend follow-up within 48 hours of discharge, only one-half of the
obstetricians surveyed advised follow-up at this time. In contrast to the
guidelines, most obstetricians defined early discharge as that occurring within
24 hours after vaginal delivery and 72 hours after cesarean delivery; most
defined optimal lengths of stay within the 48-hour (after vaginal delivery) and
96-hour (after cesarean delivery) periods considered short by the guidelines.
CONCLUSIONS: Current postpartum early discharge and follow-up practices emphasize
the physical health of the mother and place little emphasis on social risk. They
appear to be influenced by perceptions of the appropriateness of the length of
stay and are not in agreement with professional guidelines.
PMID- 9767219
TI - Intention to breastfeed in low-income pregnant women: the role of social support
and previous experience.
AB - BACKGROUND: The purpose of this study was to describe the relationship between
breastfeeding intention among socioeconomically disadvantaged pregnant women and
maternal demographics, previous breastfeeding experience, and social support.
METHODS: A cross-sectional, convenience sampling strategy was employed for data
collection. Low-income women (n = 1001) in a public hospital completed a six-page
questionnaire about their infant feeding plans, demographics, and social support.
Simple regression analyses were conducted to compare maternal breastfeeding
intention with the hypothesized correlates. RESULTS: Breastfeeding intention was
positively correlated with older maternal age, higher education, more
breastfeeding experience, Hispanic ethnicity, and hearing about breastfeeding
benefits from family members, the baby's father, and lactation consultants, but
not from other health professionals. Health professionals' attitudes were less
influential on women's infant feeding decisions than the attitudes and beliefs of
members of women's social support networks. When controlling for breastfeeding
experience (none vs any), some findings, varied, indicating a need for
breastfeeding interventions tailored to women's level of experience. CONCLUSION:
Use of peer counselors and lactation consultants, inclusion of a woman's family
members in breastfeeding educational contacts, and creation of breastfeeding
classes tailored to influential members of women's social support networks may
improve breastfeeding rates among low-income women, especially those with no
breastfeeding experience, more effectively than breastfeeding education to
pregnant women that is solely conducted by health professionals.
PMID- 9767220
TI - What contributes to breastfeeding success after childbirth in a maternity ward in
Finland?
AB - BACKGROUND: The study objective was to gain information about factors that
contribute to the successful establishment of breastfeeding in first-time mothers
while they are still in the maternity hospital. The study was part of a wider
longitudinal project that examined the development of first-time mothers into
motherhood during eight months after the birth. METHODS: Data were collected by a
questionnaire distributed between January and May 1995. The sample comprised 326
first-time mothers, who completed the questionnaires on about the fifth day after
childbirth. A polychotomic logistic regression analysis was applied. RESULTS:
Mothers who had a positive experience of breastfeeding in the maternity ward and
who began lactating 2 to 3 days postpartum coped better with breastfeeding than
those whose experience was less positive and who lactated later. Moreover, the
greater the emotional (affect) and concrete (aid) support received by the mother
from members of her support network, the better she coped with breastfeeding. By
contrast, those mothers who were upset while in the maternity ward coped less
well with breastfeeding. CONCLUSIONS: Establishing successful breastfeeding in
first-time mothers requires the professional guidance and support of the
maternity staff and paying attention to the person closest to the new mother, who
in this study was the spouse or father of the child.
PMID- 9767221
TI - Maternal perceptions of labor with fetal monitoring by pulse oximetry in a
research setting.
AB - OBJECTIVE: Little research has evaluated maternal experience with fetal pulse
oximetry for fetal surveillance. The purpose of this study was to compare
maternal perceptions of labor with intrapartal cardiotocography with or without
fetal pulse oximetry in a research setting. METHODS: One hundred women with
vaginal, vertex deliveries and uncomplicated fetal outcomes were enrolled. The
study group was a subset of 50 mothers who had participated in a pulse oximetry
trial. The control group of 50 mothers was monitored by cardiotocography only.
Both groups were matched for age, parity, weeks of gestation, epidural anesthesia
use, and duration of labor. A global measure of maternal perception of labor was
established by experience with labor, general attitude toward monitoring devices,
satisfaction with monitoring, nursing and medical care, and anxiety, each of
which was evaluated separately. The mothers in the study group were also
interviewed about aspects related to the fetal pulse oximetry research setting,
such as information, movement restriction, discomfort, care, privacy, and safety.
The questionnaires were based on a standardized rating scale model, and the
interviews were conducted two to four days after delivery. The results were
analyzed by chi-squared, paired t test, and ANOVA. RESULTS: No significant
differences were observed between the study and control participants in any
parameter concerning the maternal perception of labor. Mothers' experiences with
pulse oximetry as assessed by interview was overwhelmingly positive. CONCLUSIONS:
Fetal monitoring by pulse oximetry in a research setting did not affect maternal
perceptions of labor. Mothers' experiences with pulse oximetry were highly
positive, suggesting that research in fetal pulse oximetry need not compromise
maternal perceptions of labor.
PMID- 9767222
TI - Maternity care in The Netherlands: the changing home birth rate.
AB - In 1965 two-thirds of all births in The Netherlands occurred at home. In the next
25 years, that situation became reversed with more than two-thirds of births
occurring in hospital and fewer than one-third at home. Several factors have
influenced that change, including the introduction of short-stay hospital birth,
hospital facilities for independent midwives, increased referral rates from
primary to secondary care, changes in the share of the different professionals
involved in maternity care, medical technology, and demographic changes. After a
decline up to 1978 and a period of relative stability between 1978 and 1988, the
home birth rate started to decline further, to the extent that it might
destabilize the Dutch maternity care system and the role of midwives in it. The
Dutch maternity care system depends heavily on primary caregivers, midwives and
general practitioners who are responsible for the care of women with low-risk
pregnancies, and on obstetricians who provide care for high-risk pregnancies. Its
preservation requires a high level of cooperation among the different caregivers,
and a functional selection system to ensure that all women receive the type of
care that is best suited to their needs. Preserving the home birth option in the
Dutch maternity care system necessitates the maintenance of high training and
postgraduate standards for midwives, the continued provision of maternity home
care assistants, and giving women with uncomplicated pregnancies enough
confidence in themselves and the system to feel safe in choosing a home birth.
PMID- 9767223
TI - Ethnic differences in birth outcomes: the search for answers continues.
PMID- 9767224
TI - Sheila Kitzinger's letter from Europe: court-ordered cesareans in the United
Kingdom.
PMID- 9767227
TI - Editor's choice
PMID- 9767228
TI - Port-wine stains unresponsive to pulsed dye laser: explanations and solutions.
AB - The flashlamp-pumped pulsed tunable dye laser has represented a significant
advance in the treatment of port-wine stains (PWS). However, not all patients
will respond. In this review, the clinical features influencing the response of
PWS to the pulsed dye laser will be discussed. Theoretical and clinical data are
presented to explain why not all PWS will respond to this laser. Methods to
overcome the problems of non-responding PWS are suggested, including new
treatment devices and techniques.
PMID- 9767226
TI - Cesarean delivery rates in Chile.
PMID- 9767229
TI - Immunohistochemical demonstration of carcinoembryonic antigen and related
antigens in various cutaneous keratinous neoplasms and verruca vulgaris.
AB - Carcinoembryonic antigen (CEA), which is a well-known marker for the normal sweat
gland apparatus and its neoplasms in the skin, was recently demonstrated in
sebaceous neoplasms. The aim of this study was to examine the expression of CEA
and related antigens in the other cutaneous keratinous neoplasms and verruca
vulgaris. Normal adult skin, squamous cell carcinoma (SCC), senile keratosis,
Bowen's disease, basal cell carcinoma (BCC), seborrhoeic keratosis and verruca
vulgaris were stained immunohistochemically with a panel of monoclonal and
polyclonal antibodies that recognize different epitopes of CEA and related
molecules. Localization of the antigens was compared with that of involucrin and
proliferating cell nuclear antigen. The strongest expression of CEA-related
antigens, other than non-specific cross-reacting antigen (NCA) -50/90, was seen
in SCC and verruca vulgaris, while no detectable expression was seen in BCC.
Senile keratosis, Bowen's disease and seborrhoeic keratosis showed the
predominance of the CEA-related antigens over CEA weakly expressed. Strong
expression of both CEA and NCA-50/90 was seen only in SCC. All the expressions
were limited to the cells situated in the upper epidermal cell layers of the
tumours, at the centre of tumour islands in SCC and along the pseudohorn cysts in
seborrhoeic keratosis, where involucrin was coexpressed. We suggest that CEA and
related antigens are not only markers for sweat gland differentiation in the
skin, as currently accepted, but are also expressed in various cutaneous
keratinous neoplasms and verruca vulgaris. The expression may correlate with the
terminal differentiation of the tumour cells, the strong coexpression of CEA and
NCA-50/90 may correlate with the malignant potential of the tumour types, and the
mechanisms that control the expression of CEA and related antigens in the
neoplasms may be similar to those operative in verruca vulgaris.
PMID- 9767230
TI - Fas ligand is expressed in normal skin and in some cutaneous malignancies.
AB - Fas, a cell surface receptor and member of the tumour necrosis factor receptor
superfamily, induces apoptosis upon oligomerization by its ligand (Fas ligand:
FasL). Detailed studies have revealed that Fas is broadly expressed in normal
human tissues, but relatively little is known about the range of cell types
capable of expressing FasL. The aim of this study was to determine the in vivo
patterns of expression of Fas and FasL in human skin tissues.
Immunohistochemistry was performed using paraffin-embedded samples of normal and
neoplastic skin tissues. In normal skin, FasL was expressed in the epidermis,
sebaceous glands, sweat glands and outer root sheath of the hair. In squamous
cell carcinomas (SCC), all cases analysed expressed FasL at high levels, whereas
60% of basal cell carcinomas (BCC) were positive for FasL. Expression of Fas in
normal skin was observed in the basal and spinous layers of the epidermis, the
outer root sheath of the hair, and the sebaceous glands. Expression of Fas was
observed in all the SCC tested and none of the BCC tested. Expression of FasL by
normal cells and tumour cells in skin tissue, demonstrated for the first time in
the present study, may provide an important clue to understanding skin
physiology, and immune evasion of skin tumours.
PMID- 9767231
TI - Expression of fibrogenic cytokines in desmoplastic malignant melanoma.
AB - Desmoplastic malignant melanoma (DMM) consists of amelanotic spindle-shaped
melanoma cells and is accompanied by desmoplasia with fibrous stromata. It has a
strong tendency for local infiltrative growth and recurrence and a propensity for
neurotropism. It is not yet known which cytokine is responsible for the
desmoplasia in DMM. In the present study, we investigated the roles of several
fibrogenic cytokines and cytokine receptors in DMM: basic fibroblast growth
factor (bFGF), connective tissue growth factor (CTGF), transforming growth factor
beta, platelet-derived growth factor (PDGF) and PDGF receptors. Immunostaining
and in situ hybridization were conducted in four cases of DMM and four cases of
amelanotic malignant melanoma (AMM) as negative controls for desmoplasia. PDGF
beta receptor, bFGF and CTGF were intensely expressed in the DMM specimens in
comparison with the AMM specimens. The reaction of PDGF-B ligand and CTGF to PDGF
beta receptor, in addition to the expression of bFGF, may contribute to the
desmoplasia in DMM.
PMID- 9767232
TI - Expression of CD95 ligand in melanocytic lesions as a diagnostic marker.
AB - CD95 ligand (CD95L) potently induces apoptosis by activating CD95 on target
cells. It has recently been reported that melanoma cells in vivo express a
significant amount of CD95L, thereby being immediately able to kill CD95-bearing
immunocompetent cells specific for cancer antigens, which infiltrate the lesions.
In this study, we employed immunohistochemistry using an antibody directed
against CD95L to investigate at which stage the melanoma CD95L expression is
turned on. Skin biopsies of 49 lesions from 46 patients were assessed. These
included benign and dysplastic naevi, melanoma in situ, stage I melanomas
(Clark's level 2 or 3), advance-phase melanomas (Clark's level 4 or 5) and lymph
node metastases. CD95L was expressed in all of the advance-phase melanomas as
well as lymph node metastases of cutaneous origin, whereas neither melanoma in
situ, benign naevi nor dysplastic naevi reacted positively with the antibody. To
investigate a link between positivity and tumour size, the data were analysed on
the basis of Breslow thickness, and indicated that expression was observed only
when tumours were thicker than 0.75 mm. We next compared expression of CD95L and
HMB-45. CD95L was positive only in melanomas in a more advanced phase than stage
I, whereas HMB-45 was not only expressed in melanoma cells but also in benign
pigmented naevi. This indicated the advantage of CD95L staining to diagnose
melanoma. The present study indicates the significant correlation between
tumorigenicity and expression of CD95L, and thereby raises the possibility that
CD95L may be a useful diagnostic marker for malignant melanomas.
PMID- 9767233
TI - Functional regulation of tyrosinase and LAMP gene family of melanogenesis and
cell death in immortal murine melanocytes after repeated exposure to ultraviolet
B.
AB - This study characterizes the induction of melanogenesis and the expression of
tyrosinase, tyrosinase-related protein (TRP) and lysosome-associated membrane
protein (LAMP) gene families in the cultured melanocyte lines of non-agouti mice
with four major genetic loci, i.e. melan-a2 (black, wild type), melan-b (brown,
TRP-1 mutation), melan-s (black, piebaldism mutation) and melan-c (white,
tyrosinase mutation) in response to repeated exposure to ultraviolet (UV) B (5
mJ/cm2, 7 consecutive days). Electron microscopy showed that new melanogenesis
was induced in melan-a2, melan-s and melan-b melanocytes. Melan-a2, melan-s and
melan-b showed an almost twofold increase in tyrosinase activity and gene
expression with increased synthesis of melanosomes, although melan-b showed a
minimum increase in tyrosinase activity. There was a twofold upregulation of LAMP
1 mRNA but no alteration in LAMP-2 and LAMP-3 mRNA expression in melan-a2, while
there was no alteration in LAMP-1 mRNA expression but increased expression of
LAMP-2 and LAMP-3 mRNA in melan-s, LAMP-3 showing a higher increase. Melan-b
cells showed the same gene expression of LAMP-1, LAMP-2 and LAMP-3 as that of non
UV exposed cells. All three lines, however, exhibited simultaneously cell death,
melan-b reaching the highest rate of cell death (96.5%). In contrast, melan-c,
which did not have any tyrosinase activity with failure of melanogenesis
induction, expressed all the mRNAs of the tyrosinase and LAMP gene families, but
was not associated with any significant melanocyte death. Our study indicated:
(i) that melanogenesis induction and melanocyte death are two photobiological
processes occurring simultaneously after repeated UVB exposure, (ii) that in
response to an upregulation of tyrosinase mRNA and enzymic activity, there was a
co-ordinated upregulation of the LAMP-1 gene in wild type melan-a2, while no
upregulation was found in melan-s and melan-b mutants, and (iii) that UV-induced
melanocyte death is related to the upregulation of the tyrosinase gene, induction
of new melanogenesis and mutation of the TRP-1 gene in immortal murine
melanocytes.
PMID- 9767234
TI - Modulation of melanocyte-stimulating hormone receptor expression on normal human
melanocytes: evidence for a regulatory role of ultraviolet B, interleukin-1alpha,
interleukin-1beta, endothelin-1 and tumour necrosis factor-alpha.
AB - Melanocyte-stimulating hormone (MSH) receptor binding activity and melanocortin-1
receptor (MC1-R) gene expression on normal human melanocytes have been studied as
responses to the effects of ultraviolet B (UVB), interleukin-1 (IL-1), endothelin
1 (ET-1) and tumour necrosis factor-alpha (TNF-alpha), which are known as UV
sensitive regulators of melanocytic function. MSH receptor (MSH-R) binding
activity was upregulated by UVB, IL-1alpha, -1beta and ET-1, but was
downregulated by TNF-alpha. Northern blot analysis showed that MC1-R mRNA
expression was induced 24 h after UVB irradiation in a dose-dependent manner, and
that 24-h treatment with ET-1 also induced an expression of MC1-R mRNA, whereas
TNF-alpha downregulated the expression. In addition, IL-1alpha and -1beta have a
small but real inductive effect on MC1-R mRNA expression. Taken together, our
results suggest a model in which higher MC1-R mRNA expression is accompanied by
upregulation of MSH-R binding activity, and enhanced by UVB or cytokines
sensitive to UVB. Such a regulatory system would enable normal human melanocytes
to respond to MSH more efficiently and induce an increase of melanization of the
skin through the MSH/MSH-R system after UVB radiation.
PMID- 9767235
TI - Ultraviolet B induced suppression of induction of contact sensitivity in human
skin is not associated with tumour necrosis factor-alpha-308 or interleukin-10
genetic polymorphisms.
AB - Low doses of ultraviolet B (UVB) can induce localized immunosuppression in skin.
This effect may be important in the induction of skin cancers and is thought to
be mediated by tumour necrosis factor (TNF) alpha and interleukin (IL) 10 in
conjunction with other factors. In humans a transition polymorphism in the TNF
alpha gene may affect TNF-alpha secretion and the promoter region of the IL-10
gene contains a CA repeat polymorphism which may affect gene function. We have
therefore investigated the association of these polymorphisms with UVB-induced
immunosuppression in humans. Volunteers (n = 42) were irradiated with UVB then
sensitized on irradiated skin with diphenylcyclopropanone (DPCP) and subsequently
antigen challenged with DPCP. DNA was extracted from blood samples and volunteers
genotyped for the TNF-alpha polymorphism by polymerase chain reaction (PCR) and
restriction digestion. The CA repeat polymorphism was amplified by PCR and sized
by gel electrophoresis. Twenty-four volunteers were susceptible to UVB-induced
immunosuppression and 18 were resistant. The association of allele frequencies
and phenotype was statistically tested using a chi2-test. For both the TNF-alpha
and IL-10 polymorphisms, there was no statistically significant association
between allele types and response to UVB. These results indicate that variation
in the immune response to UVB in humans is not associated with the TNF-alpha-308
transition or IL-10 CA repeat polymorphisms, although other as yet undetected DNA
sequence variants of these genes may be involved.
PMID- 9767237
TI - Effect of granulocyte macrophage-colony stimulating factor on Langerhans cells in
normal and healthy atopic subjects.
AB - Granulocyte macrophage-colony stimulating factor (GM-CSF) is a multipotent
cytokine produced by many cutaneous cell types including keratinocytes.
Langerhans cells (LC) represent the major antigen-presenting cells in skin, and
in vitro studies demonstrate that GM-CSF is of pivotal importance in LC. Healthy
volunteers (n = 3 non-atopic, n = 3 with atopy) received recombinant human GM-CSF
(0. 05 microg/mL) by intradermal injection for 3 days to the same site. Diluent
was injected in a similar manner as control. Biopsies were taken 24 h after the
final injection and examined immunohistochemically for LC and inflammatory cell
markers. Compared with control sites, intradermal GM-CSF resulted in shortening
of dendritic cell processes and redistribution of LC in the epidermis; numbers of
CD1a + cells in the epidermis were significantly decreased (P < 0.005), while
those in the dermis were significantly increased (P < 0.05) following intradermal
GM-CSF when compared with controls. Double labelling studies on epidermal CD1a +
cells indicated de novo expression of intercellular adhesion molecule (ICAM)-1
and increased expression of HLA-DR following GM-CSF (P < 0. 005, P < 0.005,
respectively). Additional findings included a marked mixed inflammatory cell
infiltrate in the dermis and increased expression of the endothelial cell
adhesion molecules E-selectin and ICAM-1. These data indicate that in normal
human skin, GM-CSF induces changes in the phenotype and distribution of CD1a +
cells consistent with LC functional maturation and exit from the epidermis to the
dermis. As these events are central to the initiation of cutaneous inflammation,
GM-CSF may potentially play a critical role in the pathogenesis of inflammatory
dermatoses.
PMID- 9767236
TI - Comparative immunotoxicology of ultraviolet B exposure I. Effects of in vitro and
in situ ultraviolet B exposure on the functional activity and morphology of
Langerhans cells in the skin of different species.
AB - Ultraviolet (UV) B-induced morphological and functional changes in the skin of
mice, rats and humans were investigated. Changes in the morphological structure
of Langerhans cells (LC), the major antigen-presenting cells in the skin, using
confocal laser scanning microscopy, were found in mouse and rat skin after in
situ exposure to high doses of UVB radiation (FS40) (3-9 kJ/m2). Similar UVB
doses failed to induce alterations in the morphological structure of human LC.
Alterations in the function of epidermal cells (especially LC) were studied,
using the mixed skin lymphocyte response (MSLR). In vitro UVB exposure of
epidermal cells (EC), derived from the skin of the different species, revealed
that low doses of UVB radiation impaired the stimulatory capacity of these cells
dose-dependently; mouse epidermal cells were most UVB-susceptible, while human
cells were least UVB susceptible. For suppression of the stimulatory capacity of
EC after in situ UVB exposure of skin tissue, higher doses of UVB radiation than
the in vitro UVB exposure were needed in all species tested. Also in this in situ
set-up mouse epidermal cells were most UVB-susceptible, and human epidermal cells
were least UVB-susceptible. The magnitude of differences in susceptibility for
UVB-induced changes in the stimulatory capacity of EC after in situ and after in
vitro exposure experiments was similar. Firstly, it may be concluded that UVB
impairs the functional activity of LC at a lower dose than that which alters the
morphology of these cells. Secondly, it is clear that epidermal cells, especially
LC, from the skin of rodents are more susceptible to UVB than epidermal cells
derived from human skin. It is important to account for these differences in
susceptibility when data on the effects of UVB radiation on the immune system in
rodents are extrapolated to humans.
PMID- 9767238
TI - Expression of the small heat shock protein HSP 27 in developing human skin.
AB - The 27 kDa heat shock protein (HSP 27) is expressed in keratinocytes of the upper
epidermal layers, and recent evidence suggests that this protein is involved in
the regulation of epidermal differentiation. The expression of HSP 27 was
investigated in developing human skin by immunohistochemistry utilizing a
specific monoclonal antibody. We used formalin-fixed, paraffin-embedded tissue of
abdominal skin obtained from 34 human fetuses ranging between 13 and 30 weeks
estimated gestational age (EGA). We found that HSP 27 is not expressed in
keratinocytes until week 14 EGA. At this stage staining is observed in the
periderm and the upper intermediate cells but not in hair germs. During further
development, HSP 27 expression correlates with increasing epidermal
differentiation, i.e. shedding of the periderm and beginning of keratinization.
HSP 27 expression is confined to the upper cell layers and sparse basal cells. In
hair follicles, HSP 27 can be detected in the innermost cell layer of the outer
root sheath and in keratinocytes of the bulge identical to what is observed in
adult skin. The hair papilla, matrix cells and sebaceous glands are negative for
HSP 27 and remain so during further development. In eccrine sweat glands of the
24th week EGA, HSP 27 is confined to the superficial cell layer of the sweat
ducts. In the present report we demonstrate differentiation-related expression of
HSP 27 in developing human skin. Further in vitro studies will address the
molecular function of HSP 27 in epidermal differentiation and development.
PMID- 9767239
TI - Seborrhoeic dermatitis is not caused by an altered immune response to Malassezia
yeast.
AB - The immune response of patients with seborrhoeic dermatitis and healthy age- and
sex-matched controls was examined to test the hypothesis that an inadequate or
inappropriate immune response to Malassezia yeast leads to seborrhoeic
dermatitis. Antibody responses were examined using enzyme-linked immunosorbent
assays (ELISAs) and Western blots and lymphocyte responses using lymphocyte
proliferation assays. The level of IgG and IgM specific for whole yeast cells or
extracted proteins of two isolates of M. furfur was tested in ELISA. A wide range
of antibody levels was found but the patient and control groups were
indistinguishable (n = 19), and the groups could not be distinguished by the
pattern of Malassezia proteins recognized by their sera in Western blots. The
average affinity of the subjects' antibodies specific for Malassezia cells or
proteins was measured using ammonium thiocyanate dissociation. Most of the sera
had moderate affinities corresponding to 50% dissociation at thiocyanate
concentrations of 0.5-1.0 mol/L. There was no difference between patients and
matched controls. The proliferation of the patients' lymphocytes in response to a
number of M. furfur cell preparations was measured: whole cells, cytoplasmic
proteins, cell walls, soluble molecules extracted from the cell walls using
sonication, and a commercial preparation. There was a wide range of responses
between individuals, but there was no difference between the three groups:
patients with seborrhoeic dermatitis (n = 16), healthy controls (n = 16) and a
group suffering from other inflammatory skin conditions (n = 15). The results do
not support the hypothesis that an inadequate immune response to Malassezia yeast
could lead to seborrhoeic dermatitis. Other possible pathological mechanisms
include toxin production or lipase activity.
PMID- 9767240
TI - Allergens in combination have a synergistic effect on the elicitation response: a
study of fragrance-sensitized individuals.
AB - Perfume ingredients were chosen as model substances to study the effect of
allergens in combination on the elicitation response. Two groups of eczema
patients were studied. One consisted of 18 subjects with a contact allergy to two
fragrance substances and the other was a control group of 15 subjects allergic to
only one of the same two fragrance substances. The test and matched control
subject were patch tested in exactly the same way with two allergens applied in
serial dilution in separate chambers on one side and combined in one chamber on
the other side of the upper back. The assessment of reactions was carried out on
day 3 by clinical grading and laser Doppler flowmetry, and the extent of the
reaction was measured in millimetres. The data were analysed by logistic dose
response models. It was found that the combination of two allergens in
individuals allergic to both substances had a synergistic effect on the
elicitation response evaluated by all three methods. The 1 : 1 mixtures of the
two allergens elicited responses as if the doses were three to four times higher
than those actually used, which is significantly more than expected if an
additive effect had been present. In the control group, no increased response was
seen to the combined allergens compared with the allergens tested separately. The
synergistic effect demonstrated is likely to apply to other contact allergens as
well and should be taken into account in designing diagnostic tests and
performing safety assessments.
PMID- 9767241
TI - Treatment of venous leg ulcers with cryopreserved cultured allogeneic
keratinocytes: a prospective open controlled study.
AB - Twenty-seven patients with chronic venous leg ulcers were assigned to two
treatment groups. Fifteen were treated with cryopreserved cultured allogeneic
keratinocyte sheets and compression bandages and 12 with compression only. The
observation time was 8 weeks and the keratinocyte grafting procedure was
performed once weekly. The mean reduction of the initial wound area was 35% in
the treatment group and 14% in the control group. This difference was not
significant. The poor effect on wound healing given by the cryopreserved
allogeneic keratinocyte sheets contrasts with our earlier experience using fresh
keratinocyte sheets. We believe that this is due to a weakened condition of the
cryostored cells, as we have shown a loss in protein synthesis capacity of at
least 50%.
PMID- 9767242
TI - The incidence and prognosis of nail apparatus melanoma. A retrospective study of
105 patients in four English regions.
AB - Our population-based study establishes epidemiological data on age-specific
incidence rates, clinical presentation, Breslow microstaging, treatment and
survival of nail apparatus melanoma (NAM) patients in England. Four cancer
registries, covering a population of 10.6 million, recorded 105 cases of NAM
during the period 1984-93. During the same decade there was a total of 7585
patients with cutaneous melanoma and NAM represents 1.4% of all cutaneous
melanoma. The incidence rate of NAM in English patients is 0.1 per 100,000 of the
population per annum. Amelanotic melanoma was the clinical presentation in 24 of
our NAM cases. The overall prognosis is poor with an observed 5 year survival of
only 51%. Patients with NAM less than 2.5 mm Breslow depth have a 5 year survival
of 88% and are twice as likely to survive compared with those with tumours
greater or equal to 2.5 mm in thickness (P < 0. 05). NAM patients are best
managed by a multidisciplinary team approach in a few key skin cancer centres.
PMID- 9767243
TI - Sun awareness in school teachers.
AB - School children are important targets for sun awareness education, but the
knowledge, attitudes and behaviour of school teachers with respect to sun
awareness are poorly understood. A questionnaire-based survey of 76 school
teachers was undertaken. Twenty-four per cent of teachers indicated previous
experience in teaching sun awareness, but 93% of teachers had no classroom
resources for teaching sun awareness. Sun awareness was perceived by respondents
as unimportant relative to other health education issues. There was considerable
scope for improvement in attitudes and behaviour of teachers with respect to sun
awareness. Teachers need more information about environmental factors which
affect strength of sunlight, individual risk factors for sunburn and sunscreen
strength. Intervention strategies involving school teachers need simple messages,
emphasizing the importance of shade, clothing and hats in sun avoidance.
PMID- 9767244
TI - Long-term outcome of severe chronic plaque psoriasis following treatment with
high-dose topical calcipotriol.
AB - We have previously reported the effectiveness of high-dose calcipotriol in
extensive psoriasis. We now report the long-term outcome in patients following
this treatment. Twenty-eight patients with severe psoriasis were treated as in
patients with high-dose topical calcipotriol for 2 weeks. There was a mean
reduction in the psoriasis area and severity index of 65%. Sixty-nine per cent
were controlled for 3 months and 42% for 6 months. The relapse rate was
comparable with that following Ingram's regimen, the in-patient stay was shorter
and the treatment more acceptable. Careful monitoring of calcium homeostasis is
mandatory.
PMID- 9767245
TI - Pigmented primary carcinoma of the breast: a clinical mimic of malignant
melanoma.
AB - A 68-year-old man had a pigmented tumour in the breast. Although the clinical
picture suggested a malignant melanoma, histology revealed that the tumour was a
primary ductal carcinoma of the breast. There was no pagetoid cell proliferation
in the epidermis. However, tumour nests contained numerous dendritic melanocytes
that could survive in the tumour nests without the existence of epidermal
keratinocytes. Further immunohistochemical study employing antibodies to
melanocyte growth factors demonstrated that anti-basic fibroblast growth factor
(bFGF) antibody was the only reagent to show a positive staining for tumour
cells. This indicated that the breast cancer cells produced bFGF, which enabled
survival of melanocytes within the tumour mass.
PMID- 9767246
TI - Merkel cell carcinoma, Bowen's disease and chronic occupational arsenic
poisoning.
AB - We diagnosed a unique case of Merkel cell carcinoma (MCC) coexisting with Bowen's
disease on the sole of the foot of a 72-year-old man who had worked for about 4
years in a factory handling inorganic arsenic. He had a past history of arsenical
keratosis and multiple Bowen's disease. The tumour first appeared as a reddish
macule and then showed marked growth over the next month. The tumour was excised
and the specimen was examined histopathologically. The tumour consisted of two
components: a group of atypical cells representing Bowen's disease in the
epidermis and another group of atypical cells with a trabecular pattern
characteristic of MCC in the dermis. Neither group of cells showed transitional
findings, and the tumour elements were divided by a clear basement membrane. The
tumour cells in the dermis were positive for neurone-specific enolase, and on
electron microscopy had dense core granules in the cytoplasm. Inorganic arsenic
can cause various cutaneous neoplasms, but to our knowledge, this is the first
report of a case of MCC associated with Bowen's disease.
PMID- 9767247
TI - Acute infiltration by non-Hodgkin's B-cell lymphoma of lesions of disseminated
herpes zoster.
AB - A man with a 15-year history of non-Hodgkin's lymphoma presented with
disseminated herpes zoster which initially responded to aciclovir. This was
shortly followed by an acute exacerbation in the sites previously affected which
was apparently resistant to antiviral therapy. Biopsy revealed a dense
monomorphic lymphocytic infiltrate below active herpes zoster which had the same
morphology and immunoreactivity as the underlying lymphoma. His clinical
condition resolved with further chemotherapy for his lymphoma and continued
treatment with aciclovir.
PMID- 9767248
TI - Peripheral nervous system involvement in a patient with large T-cell lymphoma
arising from a pre-existing mycosis fungoides.
AB - A 29-year-old man was examined for disseminated erythematous scaling patches and
plaques and reddish, partially ulcerated nodules. Histological examination showed
a dense, diffuse, epidermotropic infiltrate located in the entire dermis to the
subcutaneous tissue, composed mainly of large pleomorphic T lymphocytes.
Immunohistochemistry revealed positivity of neoplastic cells for T-cell
associated markers, negativity for CD30 antigen and for B-cell markers.
Polymerase chain reaction analysis detected a clonal amplification of T-cell
receptor gamma. Based on clinicopathological and molecular findings, the
diagnosis of large T-cell lymphoma (LCL) arising from a pre-existing mycosis
fungoides was made. Seven months after primary diagnosis, meningeal and
peripheral nervous system involvement developed with no other evidence of
systemic disease. Despite chemotherapy and radiation therapy, the patient died 3
months after the diagnosis of nervous system involvement. In patients with
cutaneous LCL, mild neurological symptoms may precede the complete diagnostic
picture by some weeks. A rapid and fatal progression characterizes the clinical
course of the disease.
PMID- 9767249
TI - Detection of anti-type VII collagen antibody in Sjogren's syndrome/lupus
erythematosus overlap syndrome with transient bullous systemic lupus
erythematosus.
AB - Bullous systemic lupus erythematosus (SLE) is a chronic, widespread, non
scarring, subepidermal blistering eruption associated with autoimmunity to type
VII collagen. We describe a patient with Sj ogren's syndrome/lupus erythematosus
overlap syndrome who showed transient blistering eruptions over limited skin
surface and in oral mucosa. At the time of aggravation, the patient's serum
contained IgG autoantibodies that bound to the dermal side of 1 mol/L NaCl-split
normal skin, as determined by an indirect immunofluorescence test, and that
reacted to type VII collagen, as determined by immunoblotting on dermal extract.
Our observations suggest that a chronic, widespread, blistering eruption is not a
prerequisite for the diagnosis of bullous SLE, and a mild, transient, blistering
eruption could be a manifestation of type I bullous SLE.
PMID- 9767250
TI - Linear cutaneous lupus erythematosus following the lines of Blaschko.
AB - We describe two Japanese girls with discoid lupus erythematosus (DLE) in whom the
condition showed a linear configuration following the lines of Blaschko. The
clinical appearance was unusual but histological examination established the
diagnosis. After reviewing the previous reports, we found that in six of eight
patients with linear 'discoid' lesions, the age at onset was under 14 years; no
patient has progressed to systemic lupus erythematosus. Patients with 'linear'
DLE may compose a certain clinical subset. We propose the term 'linear cutaneous
lupus erythematosus' which may be more suitable for the linear lesions of DLE.
PMID- 9767251
TI - Recurrent aciclovir-resistant herpes simplex in a child with Wiskott-Aldrich
syndrome.
AB - A boy with Wiskott-Aldrich syndrome suffered from thymidine kinase (TK)-altered
and aciclovir-resistant herpes simplex virus type 1 (HSV-1) skin infections. He
presented with severe herpes simplex around the left eye in March 1993 at the age
of 8 years. HSV-1 strain TAS was isolated and was shown to be susceptible to
aciclovir (50% inhibitory concentration (IC50) 0.23 microg/mL). He was treated
with intravenous (i.v.) high dose aciclovir, 2 mg/kg per h, which produced an
improvement. About 1 year later (May 1994), a severe herpes simplex infection
appeared on his face, arm, genitalia, back and foot. Treatment with i.v.
aciclovir, 2 mg/kg per h, was initiated, but the skin lesions did not improve.
HSV-1 strain TAR was isolated and was shown to be resistant to aciclovir (IC50 36
microg/mL). HSV-1 TAR and TAS were susceptible to vidarabine (IC50 4. 4 and 2.9
microg/mL, respectively). The skin lesions were treated with i.v. vidarabine, 15
20 mg/kg per day, and healed satisfactorily. However, in March 1995, the patient
again experienced a severe herpes simplex infection around the left eye. HSV-1
strain R95 was isolated and was shown to be resistant to aciclovir (IC50 36
microg/mL). Diminished sensitivity of HSV-1 TAR and R95 to aciclovir was
associated with reduced viral TK activity and loss of aciclovir phosphorylation
activity.
PMID- 9767252
TI - Creeping eruption caused by a larva of the suborder Spirurina type X.
AB - We report a 40-year-old Japanese man with a creeping eruption caused by a larva
of the nematode suborder Spirurina type X. He had eaten raw small squid
(hotaruika) 4 weeks before the serpiginous erythematous eruption appeared on his
abdomen. Routine laboratory tests revealed only slight eosinophilia in his
peripheral blood. Although we could not find the larva in an excised skin
specimen, an indirect immunofluorescence test confirmed the presence of
antibodies against larvae of the suborder Spirurina type X. We review 28 reported
cases in Japan which showed that creeping eruption caused by larvae of the
suborder Spirurina type X has the following clinical characteristics: an
incubation time of 1-4 weeks; a migratory, well-defined, narrow, serpiginous
erythematous eruption; and only slight peripheral blood eosinophilia. Excision of
the advancing end of the track was curative in our patient.
PMID- 9767253
TI - Chronic staphylococcal scalded skin syndrome.
AB - Staphylococcal scalded skin syndrome (SSSS), not previously recorded as a chronic
disease, persisted for 2 years in a 50-year-old woman with epilepsy and
cerebellar ataxia. Lesions initially suggestive of erythema multiforme and toxic
epidermal necrolysis evolved over 2 years into those typical for SSSS, with
extensive erosions and subcorneal blisters, showing an epidermal split at the
granular cell layer. Exfoliatin A-producing phage I-III Staphylococcus aureus,
previously linked only to acute mild adult cases of SSSS, was cultured from
purulent discharge in the patient's eyes, ears and open skin lesions. The roles
of epilepsy and antiepileptic medications are discussed as possible predisposing
factors.
PMID- 9767255
TI - Topical melatonin in combination with vitamins E and C protects skin from
ultraviolet-induced erythema: a human study in vivo.
AB - In this randomized, double-blind human study, the short-term photoprotective
effects of different antioxidants and their combinations were evaluated in vivo.
Vitamin C (ascorbic acid), vitamin E (alpha-tocopherol) and melatonin (N-acetyl-5
methoxytryptamine) were topically applied, alone or in combination, 30 min before
ultraviolet-irradiation of the skin. The erythemal reaction was evaluated
visually and non-invasively using different bioengineering methods (skin colour
and skin blood flow). The results showed a modest protective effect of the
vitamins when applied alone and a dose-dependent photoprotective effect of
melatonin. Topical application of combinations of both vitamins, or of melatonin
with vitamins, enhanced the photoprotective response. Better protection was
obtained by using the combination of melatonin with both vitamins. The role of
reactive oxygen species and oxygen-derived free radicals, as well as potential
sunscreening properties of the employed antioxidants, are discussed in view of
possible mechanisms to explain this elevated photoprotective effect.
PMID- 9767256
TI - Correspondence
PMID- 9767254
TI - E210K mutation in the gene encoding the beta3 chain of laminin-5 (LAMB3) is
predictive of a phenotype of generalized atrophic benign epidermolysis bullosa.
AB - Pathogenetic mutations in the genes encoding the hemidesmosome-anchoring filament
complex proteins, laminin-5 and the 180 kDa bullous pemphigoid antigen, have been
identified in patients with the inherited mechanobullous disease, junctional
epidermolysis bullosa (EB). Furthermore, there is some evidence to suggest that
precise definition of the nature of mutations in these genes may correlate to
specific phenotypes of disease. We report three junctional EB patients who carry
an identical missense mutation, E210K, on one allele of the gene encoding the
beta3 subunit chain of laminin-5 (LAMB3) in addition to different nonsense
mutations on the second allele. Two of the patients are adults and display a
specific phenotype of non-lethal junctional EB known as generalized atrophic
benign EB, which is associated with trauma-induced blisters, nail dystrophy and
alopecia. As the third patient is a young child with fewer features of this
subtype to date, identification of E210K in combination with a nonsense LAMB3
mutation may be predictive of the subsequent development of a generalized
atrophic benign EB phenotype both in this child and in other junctional EB
patients with the E210K mutation. Identification of this particular mutation has
important implications for clinical management and counselling.
PMID- 9767257
TI - Lack of mutation in the INK4a locus in basal cell carcinomas.
PMID- 9767258
TI - Hypopigmented mycosis fungoides in a light-skinned woman.
PMID- 9767259
TI - Disseminated pagetoid reticulosis: response to bath PUVA.
PMID- 9767260
TI - Cutaneous metastases from carcinoma of the nasopharynx.
PMID- 9767261
TI - The treatment of Merkel cell carcinoma and its association with
immunosuppression.
PMID- 9767262
TI - The Koebner phenomenon in Kaposi's sarcoma in a renal transplant recipient.
PMID- 9767263
TI - The management of seborrhoeic keratoses by general practitioners, surgeons and
dermatologists.
PMID- 9767264
TI - Dormant melanocytes in the dermis: do dermal melanocytes of acquired dermal
melanocytosis exist from birth?
PMID- 9767265
TI - Lichen planus following hepatitis B vaccination.
PMID- 9767266
TI - Pyoderma gangrenosum, polyarthritis and lung cysts with novel antineutrophil
cytoplasmic antibodies to azurocidin.
PMID- 9767267
TI - Neutrophilic eccrine hidradenitis induced by granulocyte colony-stimulating
factor.
PMID- 9767268
TI - Leuconychia in reflex sympathetic dystrophy: a chance association?
PMID- 9767269
TI - Mycophenolate mofetil for psoriasis.
PMID- 9767270
TI - Streptococcal cellulitis in reticulate lymphoedema selectively affects the
lymphoedematous herniations.
PMID- 9767271
TI - Pseudomonas aeruginosa folliculitis: a sporadic case from use of a contaminated
sponge.
PMID- 9767273
TI - St John's institute annual consultants and registrars advanced course in
dermatology 12-14 february 1999, london, U.K
PMID- 9767272
TI - Diseases of the hair and scalp
PMID- 9767275
TI - Varma S, lanigan SW. Pseudoporphyria caused by nabumetone. Br J dermatol 1998;
138: 549-50
PMID- 9767274
TI - Study day in occupational dermatoses, 26 november 1998, St John's institute of
dermatology, london, U.K
PMID- 9767276
TI - Skov L et al. Contrasting effects of ultraviolet-A1 and ultraviolet-B exposure on
the induction of TNF-alpha in human skin. Br J dermatol 1998; 138: 216-20
PMID- 9767277
TI - Editor's choice
PMID- 9767278
TI - Immunoreactivity of bullous pemphigoid (BP) autoantibodies against the NC16A and
C-terminal domains of the 180 kDa BP antigen (BP180): immunoblot analysis and
enzyme-linked immunosorbent assay using BP180 recombinant proteins.
AB - The 180 kDa bullous pemphigoid (BP) antigen (BP180) is known to be recognized by
sera from patients with BP, herpes gestationis (HG) and cicatricial pemphigoid
(CP). A series of previous studies using BP180 recombinant proteins has shown
that most sera from patients with BP and HG react with the NC16A domain of BP180,
an extracellular non-collagenous region just adjacent to the plasma membrane. In
contrast, the C-terminal region of BP180 has been reported to be one of the
epitopes of CP. In the present study, we examined the immunoreactivity of 110 BP
sera against the NC16A and C-terminal domains of BP180 using immunoblot analysis
and enzyme-linked immunosorbent assay (ELISA). Immunoblot analysis revealed that
100 (91%) and 26 (23.5%) of the 110 BP sera recognized the NC16A and C-terminal
domains, respectively. The results of the ELISA were correlated with those of
immunoblotting. There were no specific or significant clinical features such as
severe involvement of mucous membranes and scarring in BP patients whose sera
reacted with the C-terminal region. These findings suggest that some BP sera
react with the C-terminal region of BP180 without any association with the
characteristic clinical features of CP.
PMID- 9767279
TI - Expression of the alpha1-alpha6 collagen IV chains in the dermoepidermal junction
during human foetal skin development: temporal and spatial expression of the
alpha4 collagen IV chain in an early stage of development.
AB - To study the expression of the alpha1-alpha6 chains of type IV collagen in the
dermoepidermal junction (DEJ) during human foetal skin development, human foetal
(10 and 20 weeks of gestation) and adult skin was immunostained with specific
monoclonal antibodies to the alpha1-alpha6 chains of type IV collagen. Intense
expression of the alpha4 chain and weak expression of the alpha2 and alpha6
chains were observed in the DEJ of 10 weeks gestational skin. In contrast, the
alpha1, alpha2, alpha5 and alpha6 chains were detected in the DEJ of 20 weeks
gestational and adult skin. Preferential expression of alpha4 during the early
phase of development (10 weeks of gestation) may suggest a chain-specific
regulatory mechanism for type IV collagen expression and its potential role in
DEJ formation during development.
PMID- 9767280
TI - Altered expression of the alpha2 laminin chain in psoriatic skin: the effect of
treatment with cyclosporin.
AB - The histopathological pattern of psoriasis is characterized by dermal
inflammatory reaction and hyperproliferation of the epidermis. The mechanism of
the epidermal hyperproliferation is not completely understood, but it is probably
modulated by the basal lamina (BL), the alterations of which have not been
described. We performed the present study to evaluate the expression of the
alpha1, alpha2, beta1 and gamma1 laminin chains and collagen IV in the BL of
active psoriasis vulgaris before and after cyclosporin treatment administered
until the psoriasis was in remission. The results showed that the alpha2 chain is
weak and irregular in the lesions, while the alpha1, beta1 and gamma1 chains and
collagen IV are normal, with intense and continuous reaction. In the same
subjects, this alteration was absent in skin that was clinically unaffected.
After treatment with cyclosporin, the altered expression of the alpha2 chain
returned to normal in the healing lesions.
PMID- 9767281
TI - The antipsoriatic agent dimethylfumarate immunomodulates T-cell cytokine
secretion and inhibits cytokines of the psoriatic cytokine network.
AB - Interactions between infiltrating T cells and keratinocytes via the secretion of
the TH1 cytokines interleukin (IL) 2 and interferon gamma (INF-gamma), the
keratinocyte growth factor transforming growth factor alpha (TGF-alpha) and the
cytokines IL-6 and IL-8 are thought to be the predominant mechanisms inducing
skin lesions in psoriatic patients. Systemic treatment of psoriasis with fumaric
acid derivatives (FAEs) has been reported to be effective in the treatment of
psoriasis, but the mode of action is still unknown. To clarify this phenomenon,
keratinocytes from psoriatic patients as well as from healthy volunteers were
mono- and cocultured with HUT 78 T cells with/without the addition of FAEs; the
cytokine concentrations were then measured in the culture supernatants.
Furthermore, mRNA expression was determined in epidermal growth factor (EGF)
activated keratinocytes as well as in phytohaemagglutinin (PHA)-activated HUT 78
T cells. Only dimethylfumarate (DMF) diminished IL-6 and TGF-alpha secretion in
the psoriatic cocultures. However, it did not have this effect on cocultures from
control subjects or on monocultures. DMF suppresses EGF-induced TGF-alpha mRNA
induction in psoriatic keratinocytes. DMF inhibited INF-gamma secretion in all
cultures but stimulated the IL-10 secretion. This immunomodulation away from the
TH1 cytokine IFN-gamma to the TH2 cytokine IL-10 was confirmed in HUT 78 T cells
by Northern blot analysis. An increased number of eosinophils is a known side
effect in patients treated with this drug, suggesting a clinical relevance of
this immunomodulation in vivo. This immunomodulation and the suppression of
cytokines from the psoriatic cytokine network could be responsible for the
beneficial effect of DMF in the treatment of a hyperproliferative and TH1
cytokine-mediated skin disease.
PMID- 9767282
TI - Investigation on a novel and specific leukotriene B4 receptor antagonist in the
treatment of stable plaque psoriasis.
AB - The aim of the present study was to investigate the efficacy and clinical
tolerability of the specific leukotriene B4 receptor antagonist VML295 in the
treatment of stable plaque psoriasis. Immunohistochemical and flow cytometrical
methods were used to assess the effects on inflammation and epidermal
proliferation. VML295 in the treatment of chronic plaque psoriasis was shown to
be safe and well tolerated. After treatment, there was a statistically
significant difference between patients treated with VML295 and patients treated
with placebo with respect to the leukotriene B4-induced CD11b up-regulation on
the cell surface of polymorphonuclear leukocytes derived from peripheral blood.
Ex vivo CD11b up-regulation in the VML295-treated group was completely inhibited
after 7 days of treatment (P = 0.001). This effect persisted until the end of the
treatment period (P = 0.004 on day 15 and P < 0.0001 after 4 weeks), whereas
CD11b up-regulation in the placebo group remained unaffected. There was no
statistically significant difference in the median psoriasis area and severity
index between the treatment groups at the end of the treatment period. During
treatment, no significant histological changes were observed in the markers for
cutaneous inflammation and epidermal proliferation. Although not statistically
significant, a tendency for the increased expression of some markers of cutaneous
inflammation and epidermal proliferation was observed after 1 week of treatment
with VML295, and a decreased expression of these markers was seen after 4 weeks
of treatment with VML295. This observation could indicate anti-inflammatory
effects of VML295 appearing between 2 and 4 weeks after the start of treatment.
PMID- 9767283
TI - Nerve-induced histamine release is of little importance in psoriatic skin.
AB - Psoriatic plaques contain an increased number of mast cells. Both the histamine
concentration and release are increased in lesional skin but the underlying
mechanisms are unclear. One hypothesis is that neuropeptides transmitted from
thin sensory cutaneous nerves continuously stimulate mast cell release of
histamine. The aim of this study was to test this hypothesis by examining if
topical anaesthesia of these nerves inhibits histamine release in psoriatic skin.
The concentration of histamine was measured in microdialysates obtained from
lesional and non-lesional skin before and during topical anaesthesia.
Concomitantly skin blood flow was measured with scanning laser Doppler
(perfusion) and/or 133Xe clearance (flow) techniques in the microdialysis area.
The histamine concentrations (mean +/- SEM) were 34 +/- 4 (n = 21), 14 +/- 1.5 (n
= 18) (P < 0. 001) and 2.8 +/- 1 nmol/L (n = 10) in lesional and non-lesional
skin and plasma, respectively. After anaesthesia of the microdialysis areas the
histamine concentration in psoriatic skin increased to 44 +/- 4 nmol/L (n = 19, P
< 0.05), but remained unaltered in uninvolved skin. In anaesthetized lesional
skin the perfusion decreased from 3.7 +/- 0.2 to 2.5 +/- 0.3 V and blood flow
decreased from 14 +/- 5 to 9 +/- 1 mL/min per 100 g (P < 0.001, n = 10). The
calculated release of dermal histamine in involved skin (198 +/- 30 pmol/min per
100 g, n = 10) remained unchanged after local anaesthesia. The results indicate
that neurogenic activation of mast cells is of minor importance for continuous
histamine release in psoriatic skin and that the vasodilatation in the psoriatic
plaque is not mediated by histamine.
PMID- 9767284
TI - Narrowband ultraviolet B (TL-01) phototherapy for psoriasis: which incremental
regimen?
AB - Narrowband (311-313 nm) ultraviolet B phototherapy with the Philips TL-01 lamp is
used increasingly in the treatment of psoriasis with little information available
on the optimum irradiation regimen. We compared a high and a low incremental dose
regimen in 20 patients with symmetrical chronic plaque psoriasis using a
randomized half body study and thrice weekly exposures. Paired trunk, leg and arm
plaques of psoriasis were scored blind prior to and at each treatment for
scaling, erythema and induration. Patients were treated to clearance or minimal
residual activity and followed up until relapse. The low increment regimen
achieved a 10% reduction in the median cumulative dose to clearance (16,401 vs.
18,246 mJ/cm2) with one extra treatment in 50% of the patients. However, the
duration of treatment (median 53.5 days) was identical for both regimens except
for one patient because there were 50% fewer episodes of erythema requiring
postponement of treatment with the low increment regimen. We now favour the low
increment regimen for phototherapy in our psoriasis population.
PMID- 9767285
TI - Ultraviolet B radiation-induced production of interleukin 1alpha and interleukin
6 in a human squamous carcinoma cell line is wavelength-dependent and can be
inhibited by pharmacological agents.
AB - Ultraviolet (UV) B irradiation induces keratinocytes to produce among others the
proinflammatory cytokines interleukin (IL) 1 and IL-6. The wavelength dependence
of this UVB effect has not yet been assessed. We evaluated the potential of
different UVB wavelength regions to release cytokines from the squamous carcinoma
cell line SCL II and also assessed the effect of various putative inhibitors.
Confluent monolayers of the cells were irradiated with 0.5-2.0 mJ/cm2 UVB at 280,
290, 300, 310 or 320 (each +/- 5) nm. In additional experiments dexamethasone (10
9-10-5 mol/L), ascorbic acid, d-alpha-tocopherol or indomethacin (each 10-7-10-4
mol/L) were added to the culture medium 24 h before, immediately after or
combined before and after irradiation with 1 mJ/cm2 UVB at 280 +/- 5 nm.
Supernatants of the cell cultures were recovered at 24 h after irradiation, and
IL-1alpha or IL-6 were determined by an enzyme-linked immunosorbent assay
(ELISA). IL-1alpha and IL-6 production were induced by UVB at 280, 290 and 300
nm, the production depended on the UV dose and decreased with increasing
wavelengths. Irradiation at 310 or 320 nm did not induce cytokine production up
to the maximum dose used. The production of IL-1 alpha/IL-6 was inhibited up to
80/89% (10-7-10-6 mol/L before and after irradiation) by dexamethasone in a
concentration-dependent manner and with all conditions of incubation. Release of
cytokines was also suppressed by indomethacin, d-alpha-tocopherol or ascorbic
acid, but concentration dependence was not always evident. These results show
that particularly shorter UVB radiation, which is expected to increase due to
stratospheric ozone depletion, induces prominent production of proinflammatory
cytokines, indicating major biological effects. Different pharmacological
compounds can interfere with this effect and seem worth further evaluation with
regard to their clinical effects.
PMID- 9767286
TI - Clinically prescribed sunscreen (sun protection factor 15) does not decrease
serum vitamin D concentration sufficiently either to induce changes in
parathyroid function or in metabolic markers.
AB - Some studies have suggested that the use of sunscreens to prevent skin cancer may
put the population at risk of vitamin D deficiency. We followed 24 sunscreen
users and 19 controls over 2 years, including two summers, two winters and a
basal period (winter). Vitamin D, parathormone and bone biological markers were
evaluated each season. Mean levels of 25-hydroxyvitamin D rose in summer, with
the increments being significantly higher for the second year in the control
group. Levels decreased in winter in both groups, and were significantly lower in
sunscreen users. We did not observe any significant change in parathormone,
tartrate resistant phosphatase, total alkaline phosphatase, osteocalcin, urine
hydroxyproline or urine calcium. Clinically prescribed sunscreen creams (sun
protection factor 15) caused a minor decrease in 25-hydroxyvitamin D levels,
which did not induce secondary hyperparathyroidism or an increment in bone
biological markers.
PMID- 9767287
TI - Sunbeds in current use in Scotland: a survey of their output and patterns of use.
AB - Spectral irradiances of 100 commercially available sunbeds in current use have
been measured. Ultraviolet (UV) A and UVB doses from sunbed use have been
calculated and compared with doses likely to be received from solar radiation.
The majority of sunbeds use UVA fluorescent tubes for irradiating the body and
filtered metal halide lamps, which have a higher proportion of UVA1, for the
face. The average minimum erythemal dose per session is 0.80, but irradiances for
particular models varied by a factor of two to three primarily because of decline
in lamp output with age. The UVA dose from a session on a sunbed is similar to
that which might be received from 20 to 30 min sunbathing at a Mediterranean
resort or 1 h on a sunny day in Glasgow, while UVB doses are 20-25% of this
level. Responses from 200 current users of the sunbeds indicate that 38% had skin
types 1 and 2, that 17% had more than 100 annual sunbed sessions and that 35%
rarely or never used the goggles provided.
PMID- 9767288
TI - Extrafacial lentigo maligna melanoma: analysis of 71 cases and comparison with
lentigo maligna melanoma of the head and neck.
AB - We report a retrospective analysis of extrafacial lentigo maligna melanoma (LMM),
and a comparison with patients with LMM of the head and neck. Seventy-one
patients (22 men, 49 women) with extrafacial LMM were identified from the
Scottish Melanoma Group database for January 1979-March 1996. Their mean age (63
years) was significantly less than that of 335 patients with head and neck LMM
(mean 72 years, P < 0.001), with a significantly greater difference among women
than men. Extrafacial sites comprised 17.5% of LMMs. There was a marked body site
distribution difference between the sexes (P = 0. 001): 68% of extrafacial LMMs
in men were on the trunk while 80% in women were on the limbs, particularly the
lower leg. Extrafacial LMMs were thinner at presentation than head and neck LMMs
(P < 0.05) in both sexes, but this was not simply explained by the younger age of
these patients as there was no significant correlation between age and tumour
thickness at either extrafacial or at head and neck sites. Although the female
lower leg is a site of chronic solar exposure in older women, the other
extrafacial sites are habitually covered in the temperate Scottish climate. The
significantly younger age group of patients with LMM at extrafacial compared with
head and neck sites therefore suggests that the relationship between LMM and
sunlight is not simply related to cumulative solar exposure. The demonstration
that head and neck LMMs were thicker at presentation compared with extrafacial
sites, despite being at a more routinely visible part of the body, suggests that
there are still opportunities for targeted pigmented lesion public education.
PMID- 9767289
TI - Morphological alterations of epidermal melanocytes in photoageing: an
ultrastructural and cytomorphometric study.
AB - To examine pathological changes of melanocytes in photodamaged skin, we performed
a comparative cytomorphometric analysis and a qualitative observation of
melanocytes from sun-exposed and sun-protected facial skin at the electron
microscopic level. The characteristic ultrastructural features of melanocytes in
photodamaged skin included a statistically significant increase in their number,
a marked nuclear heterogeneity, signs of cell activation, close apposition to
photodamaged degenerate keratinocytes, degenerative changes represented by large
intracytoplasmic vacuoles, and frequent direct contacts with Langerhans cells.
Cytomorphometric analysis revealed significant decreases in cell and nuclear
sizes, increases in cell and nuclear perimeters accompanied by irregular
contours, and higher degrees of nuclear ellipticity in sun-exposed melanocytes.
This study demonstrates that there are remarkable differences in the morphology
of melanocytes between photoaged and intrinsically aged facial skin, and supports
the concept that photoageing processes contribute to cytological alterations in
melanocytes.
PMID- 9767291
TI - The influence of female sex hormones on skin thickness: evaluation using 20 MHz
sonography.
AB - Changes in skin thickness and echodensity during the spontaneous menstrual cycle,
in women taking hormonal contraceptives and pregnant women were investigated by
high-frequency (20 MHz) ultrasound. Women with a spontaneous ovulatory menstrual
cycle (group I), women taking one-phase contraceptives (group II), women taking
three-phase contraceptives (group III) and pregnant women (group IV) were
measured at the following locations: proximal and distal forearm and lower leg on
both sides. The skin was investigated during three phases of the menstrual cycle:
days 2-4 (phase A), days 12-14 (phase B) and days 20-22 (phase C). Oestradiol and
progesterone levels were determined at each phase. The pregnant women were
investigated 2 weeks prepartal and 6 weeks after delivery. Group I showed a
statistically significant increase in the skin thickness from phase A to phase B,
but not from phase B to phase C. Group II showed no significant changes in skin
thickness, whereas the skin thickness increased from phase A to phase B in group
III. In group IV, the skin was significantly thicker prepartal than after
delivery. The measured echodensity showed a negative correlation with skin
thickness in group III and in pregnant women. We were able to demonstrate that
the status of female sex hormones influences the thickness of the skin. These
results can be explained by hormone-induced water retention in the skin.
Sonography at 20 MHz is able to quantify these effects, which should be
considered when performing ultrasound measurement in women.
PMID- 9767290
TI - Epidermal Langerhans cell apoptosis is induced in vivo by nonanoic acid but not
by sodium lauryl sulphate.
AB - Exposure to irritants may cause chronic irritant contact dermatitis (ICD),
characterized by irregular epidermal thickening and a predominantly dermal
mononuclear cell infiltrate. The mechanisms involved, and why only certain
individuals are affected, are not clearly understood. Different irritants may
trigger different cellular and molecular interactions between resident skin cells
and recruited inflammatory cells. In some individuals these interactions may
become self-perpetuating resulting in persistent inflammation in the absence of
continued exposure. This study examined Langerhans cell (LC) density in
clinically normal skin of 46 patients with chronic ICD and 10 healthy
individuals, and compared the action of the two irritants nonanoic acid (NA) and
sodium lauryl sulphate (SLS) on the LCs and keratinocytes of clinically normal
skin in patients with chronic ICD. There was a higher number of LCs/mm basement
membrane in patients compared with controls, although there was no difference in
the number of dendrites/LC nor in dendrite length. SLS induced keratinocyte
proliferation after 48 h exposure, had no effect on LC number or distribution,
and induced keratinocyte apoptosis after 24 and 48 h exposure. In contrast, NA
decreased keratinocyte proliferation after 24 h exposure but this returned to
basal levels after 48 h, and induced epidermal cell apoptosis after only 6 h
exposure. NA dramatically decreased LC number after 24 and 48 h exposure, which
was accompanied by basal redistribution and decreased dendrite length. Most
significantly, NA induced apoptosis in over half of the LCs present after 24 and
48 h exposure.
PMID- 9767292
TI - The effect of long-term treatment with tacalcitol on the psoriatic epidermis. A
flow cytometric analysis.
AB - During the last decade, novel analogues of 1alpha,25-dihydroxy vitamin D3 have
been developed for the treatment of psoriasis. Recently, the efficacy of short
term treatment with the novel derivative tacalcitol (1alpha,24-dihydroxy vitamin
D3) has been documented. However, data on the long-term effect of tacalcitol on
psoriatic skin are sparse. In this study, we assessed the cell characteristics of
the psoriatic epidermis after treatment with tacalcitol for up to 24 weeks. We
investigated how long-term treatment with tacalcitol modulates the percentages of
differentiated keratinocytes, inflammation cells and basal keratinocytes, and the
percentage of cells in the SG2M phase in the basal cell population. From 11
patients who were treated with tacalcitol for up to 18 months, we obtained single
cell suspensions of a representative psoriatic lesion after 0, 8, 12, 18 and 24
weeks of treatment. A Psoriasis Area and Severity Index was performed at each
visit as well. Cell suspensions were stained with markers for inflammation
(Vim3B4), differentiation (RKSE60) and proliferation (TO-PRO-3 iodide) and
analysed flow cytometrically. Clinically, patients improved significantly after 8
weeks of treatment. This clinical effect was preserved for the rest of the period
of treatment with no further significant improvement. Proliferative activity also
decreased significantly after 8 weeks of treatment. Proliferation did not show
further significant decreases or habituation after 12, 18 and 24 weeks. For
inflammation, no statistically reliable trends could be seen. Differentiation
improved significantly after 8 weeks of treatment, but decreased again
significantly after 12 weeks. In the period from 12 to 24 weeks, no further
significant change was observed. We conclude that tacalcitol is an effective
antipsoriatic drug. Prolonged treatment with tacalcitol will generally maintain
improvement at the level reached after 8 weeks. Owing to the beneficial effect on
both clinical state and proliferation, tacalcitol is likely to be an adequate
maintenance therapy.
PMID- 9767293
TI - BAX protein is not expressed by basal cell carcinomas.
AB - BAX and related proteins encoded by the BCL2 gene family are involved in the
regulation of apoptosis. BAX is an apoptosis-promoting protein. The slow growth
of basal cell carcinoma (BCC) has so far been explained by a high apoptotic
activity. We investigated immunohistochemically 27 BCCs for expression of the
apoptosis-promoting BAX protein. BCC did not express detectable amounts of BAX
immunohistochemically. The results indicate that apoptosis in BCC does not
involve BAX protein. We propose that the apoptotic pathway in BCC is regulated by
either less common members of the BCL2 gene family or bypasses the regulation of
the BCL2 gene family.
PMID- 9767294
TI - Keratin 17 mutations cause either steatocystoma multiplex or pachyonychia
congenita type 2.
AB - Pachyonychia congenita type 2 (PC-2; Jackson-Lawler syndrome) is an autosomal
dominant disorder characterized by hypertrophic nail dystrophy, mild focal
keratoderma, multiple pilosebaceous cysts and other features of ectodermal
dysplasia. Keratin 17 (K17) is a differentiation-specific keratin expressed in
the nail bed, hair follicle, sebaceous gland and other epidermal appendages.
Previously, we have demonstrated that PC-2 is caused by mutations in K17 and that
similar mutations in this gene can present as steatocystoma multiplex with little
or no nail dystrophy. Here, we describe three unrelated kindreds carrying K17
mutations. Two of these families have identical missense mutations (R94C) in the
1A domain of K17. However, while affected members of one kindred have the
classical features of PC-2, affected persons in the other family have the
steatocystoma multiplex phenotype. In a third family with PC-2, mutation N92S was
detected, bringing the total number of distinct mutations reported in K17 thus
far to 11. These results demonstrate that K17 mutations commonly underlie both PC
2 and steatocystoma multiplex and that the alternate phenotypes which arise from
these genetic lesions in K17 are independent of the specific mutation involved.
PMID- 9767295
TI - Cutaneous presentation of nasal/nasal type T/NK cell lymphoma:
clinicopathological findings of four cases.
AB - Epstein-Barr virus (EBV)-associated T/natural killer (NK) cell lymphoma mainly
shows nasal lesions, and has recently been shown to be associated with cutaneous
T-cell lymphoma (CTCL). The detailed features of CTCL nasal metastasis have yet
to be elucidated. We report clinicopathological findings for four cases of
cutaneous T/NK cell lymphoma with metastasis to the nose. The four patients
presented progressive involvement of nasal lesions of CTCL, an aggressive course
and poor outcome. Their pathological and immunohistological findings were
consistent with peripheral T/NK cell neoplasm and, in three of four cases, EBER-1
were apparently detected in lymphoma cells by in situ hybridization, and two of
four cases were also positive for TIA-1. The polymerase chain reaction (PCR)
results showed the identical band from the skin and nasal lesions of the two
patients. We also reviewed the cases of similar clinical course and attempted to
elucidate clinical, pathological, immunological and genotypic features. The 10
reported cutaneous T/NK cell lymphomas with nasal metastasis revealed a poor
prognosis (nine of 10 died at 3-108 months). Six cases of nine showed a positive
reaction to EBV, and six cases revealed T-cell receptor beta or -gamma
rearrangement. These findings suggest that most cutaneous T/NK cell lymphoma with
nasal metastasis are similar to nasal T-cell lymphoma associated with EBV
infection. This type of cutaneous T/NK cell lymphoma likely to involve nasal
lesions and skin cases seemed to have a poor prognosis.
PMID- 9767296
TI - Iatrogenic isolated isoleucine deficiency as the cause of an acrodermatitis
enteropathica-like syndrome.
AB - We present two patients with a suspected inborn error of metabolism. A female
newborn presented with dysmorphic features and convulsions. Metabolic screening
suggested a defect in isoleucine degradation. Within 2 weeks after the
introduction of an isoleucine-restricted diet, she developed a severe
acrodermatitis enteropathica-like syndrome. The plasma level of isoleucine was
low with a normal leucine/isoleucine ratio. The second patient, a female infant
deficient in leucine as a result of a leucine-restricted diet, did not develop a
dermatosis. Isoleucine is essential for normal growth and differentiation of
keratinocytes and enterocytes. Deficiency of isoleucine, and not leucine or an
imbalance in the leucine/isoleucine ratio, may result in an acrodermatitis
enteropathica-like syndrome.
PMID- 9767297
TI - Localized peeling skin syndrome: case report with ultrastructural study.
AB - We report a young woman in whom the history, clinical features, histopathological
and ultrastructural findings led to a diagnosis of peeling skin syndrome (PSS).
PSS is a rare and not well classified genodermatosis, mainly characterized by the
spontaneous separation of the stratum corneum from the stratum granulosum. The
unusual feature in our patient was the strict localization to the palm. PSS has
been described as a more generalized disease frequently sparing palms and soles.
We propose the diagnosis label of 'localized PSS' for this previously undescribed
variant of a rare keratinization defect.
PMID- 9767298
TI - Juvenile pemphigus foliaceus.
AB - A 7-year-old girl with generalized erythematous, scaling plaques and
vesiculobullous lesions on the extremities was diagnosed as having pemphigus
foliaceus. Lesional direct immunofluorescence revealed intercellular IgG, IgA and
C3 deposition. The patient's serum gave positive reactions against one epitope of
desmoglein 3 and the epitope of desmoglein 1 in enzyme-linked immunosorbent
assays, but the blood sample for indirect immunofluorescence did not display any
circulating antibodies. The patient was successfully treated systemically with
prednisolone and dapsone. Currently, she is taking dapsone, 12.5 mg daily. She
has been free of lesions for the last 3 years.
PMID- 9767299
TI - Neonatal pemphigus vulgaris associated with mild oral pemphigus vulgaris in the
mother during pregnancy.
AB - We report a neonate with immunofluorescence-proven pemphigus vulgaris. The
condition presented at birth with widespread skin erosions and ulceration of the
oral mucosa. Histopathological and immunofluorescence studies confirmed pemphigus
vulgaris. The mother had mild oral pemphigus vulgaris treated during pregnancy
with topical corticosteroids. All the neonate's skin erosions had crust formation
at day 2 but healed completely within 2 weeks.
PMID- 9767300
TI - An unusual reaction to cold: a sporadic case of familial polymorphous cold
eruption?
AB - A 14-year-old Japanese girl had a lifelong history of skin lesions developing
after generalized exposure to cold air; the lesions were often accompanied by
systemic symptoms such as fever and chills. The skin lesions were non-pruritic,
maculopapular, erythematous eruptions and were neither urticarial nor
angioedematous. An ice-cube test was negative. Laboratory examinations showed
marked leucocytosis during an acute attack. On the basis of clinical features,
histological findings and laboratory data, although these symptoms were sporadic,
the most likely diagnosis was familial polymorphous cold eruption, which has also
been referred to as familial cold urticaria. Serum levels of granulocyte colony
stimulating factor and interleukin 6 were significantly elevated during an acute
attack after cold exposure, suggesting that both cytokines played important parts
in the development of her condition.
PMID- 9767301
TI - Autoimmune progesterone dermatitis: treatment with oophorectomy.
AB - Autoimmune progesterone dermatitis is a rare manifestation of hypersensitivity to
endogenous hormones with polymorphic clinical manifestations. We report a 28-year
old woman with a 5-year history of mucocutaneous erythema multiforme occurring
cyclically in the premenstrual period. Progesterone sensitivity was demonstrated
by challenge test with medroxyprogesterone acetate. Treatments with oestrogens,
tamoxifen and triptorelin had to be withdrawn because of intolerable adverse
effects. Oophorectomy finally cured the disease.
PMID- 9767302
TI - Distal digital keratoacanthoma: a report of 12 cases and a review of the
literature.
AB - Twelve cases of distal digital keratoacanthoma (DKA) affecting the subungual area
or the proximal nail fold are reported. The distal phalanx of the toe was
affected in three cases. Spontaneous resolution occurred in one; one other
recurred after surgery. We also discuss the link between DKA and incontinentia
pigmenti subungual tumours; these entities are indistinguishable.
PMID- 9767304
TI - Ecthyma gangrenosum-like eruption associated with Morganella morganii infection.
AB - Ecthyma gangrenosum is considered as a pathognomonic sign of Pseudomonas
aeruginosa sepsis. Lesions similar to ecthyma gangrenosum may be caused by other
organisms. We report a case of an ecthyma gangrenosum-like eruption caused by
Morganella morganii, a Gram-negative bacillus.
PMID- 9767303
TI - Progressive HHV-8-positive classic Kaposi's sarcoma: rapid response to interferon
alpha-2a but persistence of HHV-8 DNA sequences in lesional skin.
AB - The pathogenesis of Kaposi's sarcoma (KS) is often attributed to an infectious
agent. In particular, the human herpesvirus 8 (HHV-8) was currently shown to be
closely related to all known KS types, including HIV-associated KS, European
classic KS, African endemic KS and iatrogenic KS. We report here on an HIV
negative, German patient of neither Jewish nor Mediterranean descent with
disseminated classic KS showing unusual rapid progression into the tumour stage.
After systemic administration of interferon alpha-2a over 4 weeks all tumour
lesions cleared completely. Interestingly, HHV-8 DNA sequences detected by nested
polymerase chain reaction in KS lesions before the onset of treatment were still
present in lesional skin after complete remission of the tumour. No recurrence
was seen after a follow-up period of 6 months.
PMID- 9767306
TI - HLA-Cw*0602 and HIV-associated psoriasis.
AB - The aetiopathogenesis of psoriasis is unknown, but genetic and environmental
factors may be involved. Psoriasis may not be one disease but a cutaneous
inflammatory reaction pattern consequent upon several different independent or
related stimuli in susceptible individuals. There are controversial issues
regarding the immunological basis of psoriasis and the role of CD4 vs. CD8 T
lymphocytes. Psoriasis has been associated with HLA-Cw6 and Cw7 by serology and
specifically with HLA-Cw*0602 by polymerase chain reaction (PCR) typing.
Psoriasis is probably no more common in HIV infection than in the general
population; however, it may appear for the first time or pre-existing psoriasis
may worsen and be difficult to treat in HIV disease. We have investigated the
prevalence of HLA-C alleles, in the specific clinical context of HIV infection
complicated by type 1 psoriasis, in a case control study of 14 men with HIV
disease and type 1 psoriasis and 147 HIV-infected patients without psoriasis.
Typing was performed using PCR with sequence-specific amplification primers.
Eleven of 14 patients (79%) with psoriasis carried the HLA-Cw*0602 allele
compared with 24.5% of those without psoriasis (odds ratio = 11.31; 95%
confidence limits 2. 73 to 65.36; P = 0.0001). Two patients without the HLA
Cw*0602 allele carried instead the closely related Cw*0401/3 allele. The results
confirm the previously reported association between the HLA-Cw*0602 allele and
type 1 psoriasis, and suggest that the association with HLA-Cw*0602 is stronger
in HIV-associated psoriasis although this trend needs to be supported by a larger
sample. The immunodysregulation resulting from HIV infection may trigger
psoriasis in those genetically predisposed by the Cw*0602 allele. As CD8 T cells
recognize antigens in the context of class I major histocompatibility complex,
the identification of an HLA class I association in HIV-associated psoriasis
strengthens the argument for an important role for CD8 + T lymphocytes in the
immunopathogenesis of psoriasis. Investigations of the pathogenesis of psoriasis
should take account of clinical and other subtypes already identified.
PMID- 9767305
TI - Cutaneous aspergillosis: a report of six cases.
AB - Skin invasion by Aspergillus is infrequent. We here describe six
immunocompromised patients with skin manifestations caused by Aspergillus. A
heart transplant recipient developed a primary cutaneous aspergillosis; two
patients (one with chronic granulomatous disease and another treated with a high
dose of corticosteroids) presented with nodular lesions secondary to
haematogenous dissemination; and three patients with acute myelogenous leukaemia
had skin dissemination by contiguity from orbit and sinus invasion. A. flavus was
isolated in the three cases of leukaemia; the infection was due to A. fumigatus
in the transplant recipient; A. fumigatus and A. versicolor were isolated in the
patients with the secondary aspergillosis. In most cases, amphotericin B was
useful, with clinical and mycological remission in four patients. A patient with
leukaemia died without undergoing treatment, and a child carrier of chronic
granulomatous disease died after only 12 days of treatment.
PMID- 9767307
TI - Error in the original description of the psoriasis area and severity index.
PMID- 9767308
TI - The downregulation of interleukin 1 and tumour necrosis factor receptors by
topical tacalcitol (1,24(OH)2D3) in psoriasis.
PMID- 9767309
TI - Increased temperature: a potentially important side-effect of ultraviolet
radiation treatment leading to induction of interstitial collagenase/matrix
metalloproteinase-1.
PMID- 9767310
TI - The use of polymerase chain reaction in New World cutaneous leishmaniasis.
PMID- 9767312
TI - Thirty-five cases of Kimura's disease (eosinophilic lymphogranuloma)
PMID- 9767311
TI - Distribution of Merkel cells in adult human nail matrix.
PMID- 9767313
TI - Granulomatous skin lesions in a patient with ataxia telangiectasia.
PMID- 9767314
TI - Multiple cutaneous reticulohistiocytosis.
PMID- 9767316
TI - Reactive perforating collagenosis associated with periampullary carcinoma.
PMID- 9767315
TI - Verruciform xanthoma arising in an arteriovenous haemangioma.
PMID- 9767317
TI - Papulonecrotic tuberculide complicating scrofuloderma in a health-care worker.
PMID- 9767318
TI - Pyodermatitis-pyostomatitis vegetans: evidence for an entirely mucocutaneous
variant.
PMID- 9767319
TI - Acute cutaneous graft-versus-host disease with ichthyosiform features.
PMID- 9767320
TI - Neutrophil-poor Sweet's syndrome with response to potassium iodide.
PMID- 9767321
TI - Pyoderma gangrenosum with rheumatoid arthritis and pulmonary aseptic abscess
responding to treatment with dapsone.
PMID- 9767322
TI - Multiple facial eccrine hidrocystomas: effective topical therapy with atropine.
PMID- 9767323
TI - Extracorporeal photochemotherapy in nodular scleroderma.
PMID- 9767324
TI - Multiple scrotal lymphangiomas (lymphangiectases) treated by carbon dioxide laser
ablation.
PMID- 9767327
TI - Annual meeting of the british society for investigative dermatology, 7-9 april
1999, university of wales, cardiff, UK
PMID- 9767326
TI - Pathology of the skin: atlas of clinical-pathological correlation
PMID- 9767325
TI - Treatment of minocycline-induced pigmentation with the neodymium-Yag laser.
PMID- 9767328
TI - Clinicopathological workshop on skin diseases (Inflammatory dermatoses), 2
october 1998, london, UK
PMID- 9767329
TI - Popescu CM, popescu R, williams H, forsea D. Community validation of the united
kingdom diagnostic criteria for atopic dermatitis in romanian school children. Br
J dermatol 1998; 138: 436-442
PMID- 9767330
TI - A new era in cancer prevention.
PMID- 9767331
TI - Weight loss, skin rash, and cough following bone marrow transplantation for
chronic myelogenous leukemia.
PMID- 9767333
TI - Cancer screening and early detection: managing malpractice risk.
AB - PURPOSE: The purpose of this report is to educate healthcare professionals about
the legal risks of conducting cancer screening examinations and necessary risk
reduction practices. OVERVIEW: The authors describe the elements of a medical
malpractice claim, the healthcare professionals' legal standard of care, theories
of malpractice liability, common factors related to missed or delayed diagnoses,
malpractice defenses, and risk reduction practices. CLINICAL IMPLICATIONS:
Healthcare professionals, including physicians, physician assistants, advanced
practice nurses, and social workers, have been shown to be clinically effective
in cancer screening, and early detection of many cancers leads to improved long
term survival rates. Healthcare professionals who conduct cancer early detection
examinations and counsel patients in cancer screening programs need to be aware
of the common legal theories under which lawsuits are brought related to cancer
detection examinations. Important steps in reducing the risk of malpractice
include developing creative strategies to address the theories of liability in
the area of cancer screening and early detection; keeping abreast of changes in
national and international cancer screening recommendations; monitoring the
literature for approaches to decrease liability; and scrupulously maintaining
documentation of all findings and interactions among providers and between
providers and patients.
PMID- 9767334
TI - Cancer screening of older women : a primary care issue.
AB - PURPOSE: The purpose of this retrospective chart review was to examine whether
family practice physicians and residents were screening older women for breast,
gynecologic, and colorectal cancers as recommended by the American Cancer
Society, the Guide to Clinical Preventive Services, and Healthy People 2000.
METHODS: A retrospective chart review of women 60 years and older who were seen
at least twice between July 1, 1992, and June 30, 1993, in a midwestern family
practice residency program was completed. From the original sample of 660
potential subjects, a systematic random selection of every third chart was
identified for review, resulting in a sample of 201. Analysis of the data was
performed by descriptive statistics and chi-square tests. A series of multiple
regression models using age, number of visits, type and gender of provider, and
personal or family history of cancer as predictor variables was performed.
RESULTS: Breast cancer screening was offered to approximately 70% of the sample,
with only about one third of the older women receiving mammography or clinical
breast examination. Recommendations for gynecologic cancer screening were given
to 63% of the sample, with less than one third receiving Papanicolaou smears.
Recommendations for digital rectal examination, fecal occult blood test, and
flexible sigmoidoscopy were 58%, 59%, and 30%, respectively. The percentages of
patients who actually received these tests were considerably lower. CLINICAL
IMPLICATIONS: Barriers for appropriate cancer screening for older women exist for
both the provider and the patient; however, many of these obstacles can be
overcome. Improving the resident's exposure to the current recommendations,
increasing geriatric content in the training program, and initiating a reminder
system may reduce some of the provider barriers. The use of midlevel providers
may increase the preventive services offered to older women as well as educate
and empower these women to become responsible for their own healthcare. Together,
physicians and midlevel providers can become patient advocates through political
activism, encouraging legislation that guarantees payment for cancer screening
tests. Finally, primary care providers can become actively engaged in research
that explores the healthcare concerns of older women.
PMID- 9767335
TI - Leptomeningeal involvement in chronic lymphocytic leukemia.
AB - PURPOSE: This review and case report address the rare complication of
leptomeningeal involvement in patients with chronic lymphocytic leukemia.
OVERVIEW: Chronic lymphocytic leukemia is the most common form of leukemia, with
more than 200,000 cases reported in the past 20 years. An uncommon complication
of the disorder is central nervous system invasion. To date, only 21 cases have
been reported, and their presenting symptoms have been heterogeneous and often
nonspecific, including headache, cranial nerve abnormalities, confusion, ataxia,
nausea, vomiting, and fever. The diagnosis is confirmed by the presence of a
clonal population of lymphocytes in the cerebrospinal fluid. Treatment is either
intrathecal or intraventricular chemotherapy with adjuvant radiation therapy or
radiation alone. Prognosis is improved by prompt and aggressive therapy. In this
case report, a 61-year-old man developed severe ataxia, vertigo, and occipital
headaches 4 weeks after diagnosis with otherwise asymptomatic chronic lymphocytic
leukemia. After treatment with both radiation to the head and neck and
intrathecal methotrexate the patient achieved complete symptom resolution. Thus
far, no additional systemic cytotoxic chemotherapy has been necessary. CLINICAL
IMPLICATIONS: Because central nervous system invasion is uncommon in chronic
lymphocytic leukemia, it may go undiagnosed and under-reported. Providers of
patients with this disease need to be aware of possible central nervous system
invasion when patients present with cranial nerve signs or symptoms and/or
nonspecific neurologic manifestations. Early identification and prompt central
nervous system-directed chemotherapy can affect morbidity and quality of life
positively.
PMID- 9767336
TI - The role of the physician as an information source on mammography.
AB - PURPOSE: The value of mammography for asymptomatic women younger than 50 years of
age has been under debate, and it had been suggested that each woman should
decide for herself whether to start having mammograms in her 40s. This decision
making process requires women to have knowledge of screening guidelines. This
study reported key determining informational factors that led women age 40 and
older to obtain a mammogram. DESCRIPTION OF STUDY: To examine the relationship
between sources of information and utilization of mammography, the authors
conducted a communitywide telephone survey, in English and Spanish, of a
stratified random sample of 999 white, black, and Hispanic women in Dade County,
Florida. The survey was designed to measure knowledge, attitudes, practices, and
beliefs about breast cancer, its prevention, and its early detection. Data for
784 women 40 years and older are analyzed and reported here. RESULTS: The most
commonly cited source of information was the media (90.2%). In a logistic
regression, having had a checkup in the past year was the strongest predictor of
having had a recent mammogram as opposed to a distant one (OR 4.17; 95% CI 2.92
5.95). Women who named their physician as an important source of information
about health and prevention were also more likely to have had a recent
examination (OR 1.85; 95% CI 1.27-2.69). CLINICAL IMPLICATIONS: This analysis of
the relationship between the source of information and utilization of mammography
suggests that physicians, as sources of information, serve to motivate women to
obtain a mammogram. This is true even after taking into account the patient's age
and utilization of the healthcare system for preventive care in general. For this
reason, it is imperative that clinicians be aware of national guidelines for
breast cancer screening; of the risks and benefits of screening measures; and of
the implications of a positive and negative test result. In addition, clinicians
must realize the importance of follow-up to remind the patient to obtain a
mammogram or other screening test and should develop strategies to provide this
service.
PMID- 9767337
TI - The impact of radiation therapy on quality of life in patients with cancer.
AB - PURPOSE: This study was conducted to evaluate the physical and mental status
change during and after a course of radiation treatment in patients with cancer.
DESCRIPTION OF STUDY: Twenty-four patients with various malignant diseases were
enrolled, including 9 men and 15 women, whose median age was 64.5, to receive
radiation therapy. All patients also received psychosocial support from nurses,
social workers, and/or organized support groups. The Rand 36-item survey 1.0 (SF
36) was completed at the beginning, the second week, the completion of treatment,
and 1 and 3 months after treatment for the evaluation of physical component
scores and mental component scores. Karnofsky performance scale and toxicity
scores were determined by the treating nurses and physicians. RESULTS: The
physical component scores of evaluated patients before treatment were
approximately 20% lower than those of the general U.S. population, whereas mental
component scores were similar to those of the general U.S. population. After
treatment started, Karnofsky performance scale decreased concurrently with an
increased rate of toxicity. Both physical and mental component scores were
relatively stable throughout the course of evaluation. Mental component scores
were the only predictor of toxicity during the treatment. Karnofsky performance
scale dropped to their lowest point at the completion of treatment and then
improved at 1-month follow-up. CLINICAL IMPLICATIONS: The patients who had higher
mental component scores before treatment appeared to have higher, and improving,
physical component scores throughout the course of evaluation. Along with
complementary social support, the implementation of psychosocial support early
and throughout the course of treatment may result in physical benefits and
improving overall quality of life. Care should also be taken to make psychosocial
support available to patients after the completion of treatment.
PMID- 9767338
TI - Overview of alternative/complementary medicine.
PMID- 9767339
TI - Bulletin board
PMID- 9767340
TI - Practice guidelines for patients with rare cancers.
PMID- 9767341
TI - Liposomes as drug delivery systems.
PMID- 9767342
TI - Treating mice, caring for people.
PMID- 9767343
TI - Multidisciplinary rounds: patient-family-staff dynamics: when the patient/family
are colleagues.
PMID- 9767344
TI - Influence of culture on cancer pain management in Hispanic patients.
AB - PURPOSE: The purpose of this pilot study was to describe the influence of culture
on cancer pain management in Hispanic (Mexican and Central American) patients.
DESCRIPTION OF STUDY: This qualitative study is guided by the conceptual
framework of the Pain and Quality of Life model and the Biocultural Model of
Pain. It was developed as a companion study to a National Cancer Institute (NCI)
funded project to disseminate a pain education program for adult patients with
cancer and their family care givers in community home-care agencies. After
completing the NCI study, Hispanic subjects were invited to participate in the
qualitative companion study. A total of 17 subjects, the majority of whom were
women, were interviewed. The Hispanic Pain Experience Questionnaire (HPEQ) was
used to elicit answers to open-ended questions regarding the perception and
management of cancer pain. RESULTS: Themes that emerged from the questionnaire
were Influence of Culture, Expressions of Pain, Managing Pain/Medications, and
Use of Nondrug Interventions. Responses suggest that culture, family beliefs, and
religion contribute significantly to management and expression of pain by the
patient and care giver. In addition, this group showed that pain may be
approached with stoicism; therefore, lack of verbal or behavioral expression of
pain does not indicate a lack of pain itself. These patients also demonstrated a
reliance on folk beliefs and nondrug interventions. The most common reason cited
for noncompliance with pharmacologic treatment was an inability to understand
instructions. CLINICAL IMPLICATIONS: When providing care to Hispanic patients, it
is imperative to be nonjudgmental, sensitive, and respectful. To improve
compliance, the multidisciplinary cancer team should 1) incorporate the patients'
folk healthcare practices and beliefs into the plan of care when possible; 2)
involve family members and friends in the patient's care, identifying one key
family contact; and 3) ensure that instructions for medications are available in
Spanish and understood by the patient and care giver. When patients' overall
beliefs and values are respected, compliance with pharmacological and other
interventions may increase accordingly.
PMID- 9767347
TI - Bulletin board
PMID- 9767345
TI - Telephone prescreening enhancing a model for proactive healthcare practice.
AB - PURPOSE: This article explicates the process of developing and implementing a
contemporary, innovative program using the telephone as a tool for prescreening
newly diagnosed cancer patients before their arrival at the cancer center. As
another element of existing models of psychosocial care, this service lays the
foundation for the efficient delivery of clinical social work services.
DESCRIPTION OF PROGRAM: In the Surgical Oncology Clinic of the M.D. Anderson
Cancer Center in Houston, Tex, 28 patients were contacted as part of a telephone
prescreening model of a practice program from February 1, 1995 through March 31,
1995. Using a structured telephone interview format, two clinic social workers
contacted patients and provided information on social work services. Patients
needing resource assistance were provided with community referrals. Using the
information from the telephone call, a brief outpatient assessment was completed
for each patient before his or her arrival at the clinic. During the initial
clinic visit, each new patient was met by the social worker to conduct a
qualitative interview and address specific treatment-related concerns. OUTCOME OF
PROGRAM: The patients expressed their appreciation of the interest of the social
work staff and their satisfaction with the information provided. In addition,
obtaining patient information and identifying patient needs before the initial
visit allowed social workers to use clinic time more efficiently. Because of
restructuring, the Surgical Oncology Clinic was eliminated and use of the
intervention suspended. Based on the encouraging results of the telephone
prescreening model of care program, reinstating the program in the future would
include expanding its hours of operation to reach individuals who are not at home
during the hours of 8:00 am 25:00 pm and including language assistance to address
the needs of the increasingly multicultural population. CLINICAL IMPLICATIONS:
Telephone prescreening is one strategy for personalizing psychosocial assessment.
In this era of outpatient day surgery and cost-controlled managed healthcare, the
benefits of prescreening are empowerment for both patients and multidisciplinary
team members. The future holds promise for telephone prescreening to become part
of the collaborative clinical pathways model of the disease-site centers concept.
PMID- 9767346
TI - Options in the treatment of chemotherapy-induced emesis.
AB - PURPOSE: The incidence and duration of chemotherapy-induced emesis,
pathophysiology of the emetic response, and antiemetic treatment of options are
reviewed. OVERVIEW: Nausea and vomiting are among the most common and
debilitating side effects of cancer chemotherapy. If not controlled, these side
effects may interfere with the delivery of potentially life-saving treatment.
Acute, delayed, and anticipatory nausea and vomiting may be prevented by
appropriate antiemetic therapy. Drug selection is based on the emetogenicity of
the patient's cancer treatment and potency of the antiemetic agent. Efficacy and
safety of the antiemetic regimen are often improved by combining agents with
different mechanisms of action. CLINICAL IMPLICATIONS: By preventing and
controlling chemotherapy-induced emesis, clinicians may improve cancer patients'
functional status and quality of life significantly. Improved tolerability may
lead to greater patient acceptance of chemotherapy and prevent premature
withdrawal from or cessation of treatment. Controlling chemotherapy-induced
emesis also helps to decrease the direct and indirect costs of managing cancer.
PMID- 9767348
TI - Quality of life in cancer patients: use of a revised Hospice Index.
AB - PURPOSE: Improving or maintaining the quality of life for persons with cancer is
a major goal of end-of-life care; however, to measure quality-of-life outcomes, a
valid and reliable measure is needed. The purpose of this project was to report
the psychometric properties of the revised Hospice Quality of Life Index (HQLI),
including validity and reliability for hospice patients with cancer. DESCRIPTION:
Data were collected from home care hospice patients with cancer (n = 255) and a
group of apparently healthy adults in the community (n = 32). The revised HQLI is
a 28-item self-report instrument that includes three subscales:
Psychophysiological Well-being, Functional Well-being, and Social/Spiritual Well
being. RESULTS: Evidence for validity was provided in three ways. First, factor
analysis confirmed the three subscales (Psychophysiological, Functional, and
Social/Spiritual Well-being). Second, a weak significant correlation was found
between the Easterm Cooperative Oncology Group Performance Status Rating scores
and HQLI scores (r = .26; P = .00). Third, the HQLI was able to discriminate
between hospice patients with cancer and apparently healthy adults (lambda = .34;
P = .00). In addition, the mean scores of these two groups were significantly
different (t = 6.64; P = .00). However, only a minimal difference in scores was
found on the Social/Spiritual Well-being subscale between the cancer and healthy
groups. Reliability for the revised HQLI was high for both the total scale (alpha
= .88) and the subscales (alpha =.82-.85). CLINICAL IMPLICATIONS: Emphasis has
been placed recently on understanding quality of life from the patient's
perspective. The development of a valid and reliable tool can guide care givers
in providing meaningful quality-of-life care. The HQLI provides patients the
opportunity to express beliefs about quality-of-life issues and to maintain
direction over a critical aspect of their care. Of note from this study, the
significant difference between groups in functional well-being and minimal
difference in social/spiritual well-being suggest that patients are able to
appraise their functional abilities realistically and still maintain their social
network and spiritual beliefs. Indeed, it may be that patients give family
relationships and spiritual beliefs greater focus during a terminal illness.
PMID- 9767350
TI - Controversies in cancer care: hormone replacement therapy after breast cancer:
how shall we do no harm?
PMID- 9767349
TI - Missed cancer screening opportunities among older women: a review.
AB - PURPOSE: The authors present an analysis of the literature and findings from a
qualitative research study as a framework for discussion of potential strategies
to increase utilization of breast and cervical cancer screening among older
women. The qualitative findings are one component of a comprehensive two-part
study investigating why providers miss the opportunity to screen older women for
cancer. OVERVIEW: Qualitative analysis of in-depth interviews with experts in
cancer control (academicians, clinicians, and cancer center administrators) and a
survey of primary care providers revealed four emergent themes of patient,
provider, office, and access barriers that contribute to underutilization of
screening. Patient and provider barriers represent human factors or reasons why
both groups may be reluctant to participate in screening. Office and access
barriers exemplify systems factors that impede the screening process for both
groups. Primary care providers may miss the opportunity to perform or recommend
screening for underserved groups of older women because of their perceptions of
these human and systems factors. CLINICAL IMPLICATIONS: In light of the critical
importance of primary care providers' recommendations, health professionals and
community leaders should collaborate in developing multifaceted programs to help
providers feel more comfortable about promoting screening to their patients. Such
comprehensive, coordinated initiatives, which adapt successfully proven
strategies to community needs and resources, may be essential to increase
utilization of screening among underserved groups of older American women.
PMID- 9767351
TI - Resources for alternative and complementary cancer therapies.
PMID- 9767352
TI - Capecitabine: A new oral fluoropyrimidine.
PMID- 9767353
TI - Increasing awareness of the European Society for Clinical Investigation.
PMID- 9767354
TI - Clinical implications of mutations in the hepatitis B virus genome.
PMID- 9767356
TI - Haemodynamic effects of 8-day octreotide and prazosin administration in portal
hypertensive rats.
AB - BACKGROUND: Octreotide and prazosin are both effective portal hypotensive drugs
in the control or prevention of variceal bleeding. The present study was
undertaken to investigate the haemodynamic effects of octreotide and prazosin,
alone or in combination, in portal hypertensive rats. METHODS: Portal
hypertension was induced by partial portal vein ligation. Portal hypertensive
rats were allocated into one of the four groups-vehicle group (saline, 0.5 mL 12
h-1), octreotide group (30 micrograms kg-1 12 h-1), prazosin group (0.4 mg kg-1
12 h-1), and octreotide (30 micrograms kg-1 12 h-1) plus prazosin (0.4 mg kg-1 12
h-1) group-with eight rats in each group. Prazosin or saline was administered by
gavage, whereas octreotide was administered by subcutaneous injection. The drug
was given on the day of ligation and continued for 8 consecutive days. Systemic
as well as splanchnic haemodynamic parameters were measured thereafter. RESULTS:
Portal vein-ligated rats exhibited typical hyperdynamic state compared with sham
operated rats. The portal venous pressure, portal tributary blood flow and
cardiac index were significantly reduced by treatment of octreotide, prazosin or
octreotide plus prazosin in portal hypertensive rats. Hyperdynamic parameters of
systemic, renal and portal territory vascular resistances, and renal as well as
hepatic arterial blood flow were ameliorated by treatment of octreotide or
octreotide plus prazosin in portal hypertensive rats. Overall, octreotide
treatment exerted more beneficial haemodynamic effects than prazosin treatment.
The combination of octreotide and prazosin exerted better haemodynamic effects in
cardiac index but worse effects in systemic as well as portal territory vascular
resistance than octreotide treatment alone.
PMID- 9767355
TI - Carbohydrate-deficient transferrin is not a useful marker for the detection of
chronic alcohol abuse.
AB - BACKGROUND: The role of carbohydrate-deficient transferrin (CDT) as a reliable
marker for the detection of chronic alcohol abuse has been discussed
controversially. METHODS: Therefore, we investigated CDT in the sera from 405
subjects with different alcohol intake. Besides healthy control subjects (n =
42), inpatients and outpatients in a department of gastroenterology (n = 325) and
patients admitted to a department of otorhinolaryngology (n = 38) were studied. A
total of 213 patients suffered from various forms of liver diseases, and 89
patients had liver transplantation. CDT values were determined by a double
antibody radioimmunoassay. RESULTS: In the 241 alcohol-abstinent subjects, CDT
levels ranged from 3 to 90 units L-1 (median = 12); the 92 moderate drinkers (20
60 g of alcohol per day) showed values from 3 to 40 units L-1 (median = 12), and
the 72 subjects with chronic alcohol abuse (> 60 g per day) revealed CDT levels
from 3 to 100 units L-1 (median = 16). The diagnostic specificity for alcohol
abuse was 86.8% for men (sensitivity 36.9%) and 95% for women (sensitivity 0%).
CONCLUSION: Our data indicate that measurement of CDT does not reach clinical use
in the detection of chronic alcohol abuse in an unselected population because of
its insufficient specificity and sensitivity.
PMID- 9767357
TI - Effects of omega-3 fatty acids and/or antioxidants on endothelial cell markers.
AB - BACKGROUND: Increased expression of cell adhesion molecules and increased
procoagulant activity of the vascular endothelium have been postulated to
characterize dysfunctional endothelium. The cellular effects of n-3 fatty acids
(n-3 FAs) and antioxidants are still not clarified. METHODS: In a randomized,
factorial two-by-two design study, we have investigated 41 male smokers with
hyperlipidaemia before and after 6 weeks of supplementation with either n-3 FAs
(4.8 g daily) or placebo with the addition of antioxidants (150 mg of vitamin C,
75 mg of vitamin E and 15 mg of beta-carotene daily) or placebo with regard to
the effects on some endothelial cell markers: thrombomodulin (sTM), von
Willebrand factor (vWF), tissue plasminogen activator antigen (tPAag) and soluble
forms of the cell adhesion molecules E-selectin, P-selectin and vascular cell
adhesion molecule 1 (VCAM-1). RESULTS: In the n-3 FA group, significant
reductions in the plasma levels of vWF (P = 0.034) and sTM (P < 0.001) were
demonstrated compared with placebo, whereas increased levels were found for E
selectin (P = 0.001) and VCAM-1 (P = 0.010). In the antioxidant group, no
differences in changes were noted for any of the variables. CONCLUSION: The
reduction in the levels of sTM and vWF with n-3 FA supplementation could indicate
an improvement with regard to the haemostatic markers of endothelial dysfunction,
whereas the simultaneous increase in the soluble forms of E-selectin and VCAM-1
may suggest an adverse effect on the inflammatory system. The antioxidants seem
to be neutral in their effect on these endothelial cell markers in our study
population of smokers. The interpretation of the soluble forms of these molecules
are, however, still debatable.
PMID- 9767358
TI - Cardiac natriuretic peptides for diagnosis and risk stratification in heart
failure: influences of left ventricular dysfunction and coronary artery disease
on cardiac hormonal activation.
AB - BACKGROUND: Cardiac natriuretic peptides are activated in heart failure. However,
their diagnostic and prognostic values have not been compared under the routine
conditions of an outpatient practice. METHODS: We studied the diagnostic and
prognostic value of plasma N- and C-terminal peptides of the atrial natriuretic
factor prohormone (N-proANF and ANF respectively) and brain natriuretic peptide
(BNP) to evaluate the severity of congestive heart failure (CHF) as reflected by
the New York Heart Association (NYHA) classification and to predict its 2-year
mortality. Peripheral plasma concentrations of the three natriuretic peptides
were measured in 27 normal subjects (CTR), in 32 patients with coronary artery
disease (CAD) and normal left ventricular ejection fraction and in 101 patients
with chronic CHF in functional classes I and II (n = 61) or III and IV (n = 40).
RESULTS: Plasma concentrations of the three peptides increased in the presence of
CHF in relation to its severity (P < 0.01). BNP was unable to distinguish CTR
from CAD, just as ANF could not differentiate CAD from CHF I-II; only N-proANF
displayed a significant and continuous increase from CTR to CAD, CHF I-II and III
IV. Receiver-operating characteristic curves showed better evaluation of the
degree of CHF by BNP than by ANF or ejection fraction (P < 0.05). Assessment of
the 2-year prognosis revealed that N-proANF and BNP were the best independent
predictors of outcome after the NYHA classification. These peptides identify a
very high-mortality group. CONCLUSION: Plasma N-proANF and BNP concentrations are
good indicators of the severity and prognosis of CHF in an outpatient practice.
CAD does not stimulate BNP as long as ventricular dysfunction is not present,
although increased N-proANF levels in this setting suggest an early humoral
activation.
PMID- 9767359
TI - Cardiovascular risk factors associated with clinically isolated and diffuse
atherosclerosis in Spanish patients with coronary artery disease.
AB - BACKGROUND: Patients with coronary artery disease (CAD) associated with
peripheral (PAD) or cerebrovascular disease (CVD), a condition called diffuse
atherosclerosis, have a higher risk of death than patients with isolated CAD. The
prevalence of diffuse atherosclerosis and the atherogenic risk factors associated
with this condition in our geographic area have not been described previously.
METHODS: A cohort of 2597 patients (62 +/- 10.8 years, 665 women) consecutively
admitted at Bellvitge Hospital because of acute coronary syndromes were studied.
CAD patients were divided in two groups with diffuse and located atherosclerosis
according to whether they had or they had not an associated PAD or CVD. Baseline
history, physical data and lipid profile were recorded in each patient according
to a standardized questionnaire. RESULTS: A total of 370 patients (14.2%) had
diffuse atherosclerosis. Among them, there were more men and women older than 55
years than among those with isolated CAD. Patients with diffuse atherosclerosis
were more frequently hypertensive, diabetic and former smokers than those with
isolated CAD (60.5% vs. 49.4%, P < 0.01; 37.4% vs. 24.5%, P < 0.01; and 47% vs.
35.7%, P < 0.01, respectively). There were no significant differences in the mean
values of total cholesterol (TC), low-density cholesterol (LDL-C), high-density
cholesterol (HDL-C) and triglycerides between both groups of patients, but
patients with diffuse atherosclerosis had a lower HDL-C/TC ratio, with borderline
statistical significance (0.18 +/- 0.06 vs. 0.19 +/- 0.06, P = 0.06). Using
multiple logistic regression analysis, the variables associated with diffuse
atherosclerosis in men were age greater than 55 years (OR 1.97, CI 1.33-2.93),
hypertension (OR 1.50, CI 1.14-2.20), diabetes (OR 1.78, CI 1.20-2.70), smoking
(former smokers) (OR 2.09, CI 1.36-3.24) and HDL-C/TC < 0.20 (OR 1.60, CI 1.18
2.17); and in women hypertension (OR 3.43, CI 1.48-7.94) and diabetes (OR 2.58,
CI 1.55-4.80). CONCLUSIONS: Clinically overt diffuse atherosclerosis is a
relatively common disease. Older patients and those with hypertension, diabetes
or low HDL-C/TC ratio are more likely to have diffuse atherosclerosis than those
without these conditions.
PMID- 9767361
TI - Plasma and platelet ascorbate pools and lipid peroxidation in insulin-dependent
diabetes mellitus.
AB - BACKGROUND: As diabetes mellitus represents a situation in which production of
peroxides is increased, the aim of this study was to investigate the relationship
between plasma and platelet levels of ascorbic acid (AA)/dehydroascorbic acid
(DHA) and those of malonyldialdehyde (MDA), an indirect marker of lipoperoxides,
both assayed using high-performance liquid chromatography (HPLC), in 59 patients
with insulin-dependent diabetes mellitus (IDDM) compared with 51 healthy control
subjects matched for sex, age, smoking habits, as well as for dietary intake of
energy, alcohol and vitamin C. RESULTS: Mean plasma and platelet MDA were
significantly higher in the patients affected with IDDM than in control subjects.
Moreover, the diabetic group was characterized by a huge decrease in plasma AA
[8.45 +/- 5.5 mumol L-1 (SD) vs. 33.4 +/- 7.6 mumol L-1, P = 0.0001], mirrored by
a significant increase in plasma DHA (11.9 +/- 3.9 mumol L-1 vs. 3.9 +/- 2.5
mumol L-1, P = 0.0001). No detectable DHA was observed in the platelets from both
diabetic and control subjects, whereas AA was significantly increased in
platelets from diabetic patients compared with control subjects (42.6 +/- 7.4 vs.
34.8 +/- 5.1 nmol 10(-9) platelets, P = 0.0001). Platelet AA in the diabetic
group was significantly inversely correlated with glycated haemoglobin (r =
0.34; P = 0.04) and directly with plasma AA (r = 0.39; P = 0.02), the sum of
plasma AA + DHA (r = 0.44; P = 0.009) and with platelet MDA (r = 0.38; P = 0.02).
CONCLUSION: (a) The ratio plasma AA/DHA is significantly lowered in IDDM in
association with an increase in MDA levels; (b) only AA is detected in platelets,
being augmented in the diabetic group; (c) plasma ascorbate depletion does not
reflect platelet levels of AA; and, finally, (d) metabolic control, as well as
intracellular lipoperoxides, modulates platelet AA in IDDM.
PMID- 9767360
TI - Acute and chronic exposure of rat intestinal mucosa to dextran promotes SGLTI
mediated glucose transport.
AB - BACKGROUND: The intestinal handling of dextran, an alpha-1,6-linked glucose
polymer, is poor compared with starch, and some ingested dextran might therefore
reach the lower small intestine. As luminal sugar up-regulates SGLT1 (sodium
dependent glucose transporter) locally, we report the effects of a dextran
enriched diet on jejunal and ileal brush border membrane (BBM) glucose uptake.
METHODS: Rats were maintained on a diet containing 65% maltodextrin or 32.5%
maltodextrin + 32.5% dextran (10 kD or 40 kD) for 8-10 days, and the kinetics of
phlorizin-sensitive [3H]-glucose uptake by purified BBM vesicles was determined.
RESULTS: Ingestion of 40-kD but not 10-kD dextran increased Vmax for jejunal and
ileal glucose uptake (+64.3% and +61.8% respectively, both P < 0.02). The
transport response to 40-kD dextran was in keeping with lower levels of expired
H2 at the end of the feeding period. High-performance liquid chromatography
(HPLC) analysis of luminal contents indicated extensive hydrolysis of ingested
dextran. Finally, 3-h jejunal exposure to 40-kD dextran in vivo increased the
Vmax for glucose uptake by jejunal BBM. CONCLUSION: It is likely that increased
SGLT1-mediated glucose uptake after short or longer term mucosal exposure to
dextran results from luminal dextran per se or a hydrolysis product. The clinical
implications of this up-regulation are discussed.
PMID- 9767362
TI - Transdermal nicotine inhibits interleukin 2 synthesis by mononuclear cells
derived from healthy volunteers.
AB - BACKGROUND: Smoking has either a beneficial or harmful effect on the course and
recurrence of ulcerative colitis (UC) and Crohn's disease respectively.
Transdermal application of nicotine had similar effects in UC and therefore was
considered to be an effective basic drug that could be further developed in the
search for new compounds in the treatment of acute exacerbations of
corticosteroid-resistant UC. To clarify the hypothesis that nicotine exerts its
anti-inflammatory effect in UC through selective inhibition of T-cell-derived
cytokine synthesis, we studied in vivo effects of nicotine on cytokine production
by human non-adherent mononuclear cells isolated from peripheral blood in a
randomized, double-blind, placebo-controlled trial. METHODS: Healthy non-smoking
volunteers applied for 2 weeks of nicotine patches (n = 12) with incremental
doses of nicotine during the first week to achieve a maintenance dose of 15 mg
per day, or placebo (n = 12). Blood was obtained before treatment and 1, 2, 3 and
6 weeks after the start of treatment. Cells were cultured in the absence or
presence of phytohaemagglutinin for 48 h, and total amounts of interleukin 2 (IL
2), IL-4, IL-10, IL-13, interferon gamma (IFN-gamma) and tumour necrosis factor
alpha (TNF-alpha) were measured. RESULTS: Transdermal nicotine caused a
significant inhibition of IL-2 after 2 weeks' treatment compared with the placebo
group. In addition, a diminished production of IL-10 and TNF-alpha in comparison
with day 0 was observed. CONCLUSION: The beneficial effect of transdermal
nicotine in ulcerative colitis may be mediated by a selective inhibition of the
IL-2 production by mucosal mononuclear cells, which could result in diminished
cell proliferation and consequently a reduction in the inflammatory process.
PMID- 9767363
TI - Time course of immunological markers in patients with the systemic inflammatory
response syndrome: evaluation of sCD14, sVCAM-1, sELAM-1, MIP-1 alpha and TGF
beta 2.
AB - BACKGROUND: The systemic inflammatory response syndrome (SIRS) is viewed as a
system-wide inflammatory response. Up until now, no parameter has been available
for predicting the development of septic shock. In the present study, we
evaluated the usefulness of serum levels of CD14, vascular cells adhesion
molecule-1 (VCAM-1), endothelial leucocyte adhesion molecule-1 (ELAM-1),
macrophage inflammatory protein (MIP) 1 alpha and transforming growth factor beta
2 (TGF-beta 2) as early markers of outcome in patients with SIRS. METHODS: A
group of 28 SIRS patients (13 survivors/15 non-survivors) was compared with a
healthy control group and with patients with local inflammation. Blood samples
were analysed on days 0, 4 and 7. Proinflammatory parameters such as sCD14, sVCAM
1, sELAM-1, MIP-1 alpha and anti-inflammatory parameters such as TGF-beta 2 were
determined using enzyme-linked immunosorbent assay (ELISA). RESULTS: At the
beginning, all evaluated proinflammatory immunological parameters with the
exception of sVCAM-1 were significantly increased in patients with SIRS compared
with the healthy control group. However, no significant difference could be
observed for all immunological parameters comparing survivors and non-survivors,
with the exception of interleukin (IL) 6 at day 7. CONCLUSION: All evaluated
proinflammatory parameters were increased in patients with SIRS during the course
of the disease. However, the parameters have no correlation with outcome and
prognosis of SIRS patients.
PMID- 9767364
TI - Cytokine regulation of the acute-phase protein levels in multiple myeloma.
AB - BACKGROUND: Interleukin (IL) 6 has an important role in the regulation of acute
phase proteins (APPs) during an acute-phase response. We studied IL-6 and other
cytokines to determine if they regulate serum APP levels in the same way under
the condition of the aberrant, long-lasting 'acute-phase response' that occurs in
patients with chronic inflammation and cancer. METHODS: Serum levels of nine
positive APPs [CRP, SAA, C1-INH, Bf, C5, C8, C9, alpha 1-acidic glycoprotein
(AGP) and haptoglobin] and two negative APPs [transferrin and alpha 2-HS
glycoprotein (AHSG)] were measured using immunochemical methods in 59 multiple
myeloma patients and in 72 healthy control subjects. Serum IL-6 and tumour
necrosis factor (TNF) alpha levels were determined by bioassays. RESULTS: IL-6
was negatively correlated with five out of nine (C1-INH, C8, C9, AGP and
haptoglobin) positive APPs but positively correlated with C-reactive protein
(CRP). When patients with high and low IL-6 serum concentration were compared,
CRP levels were higher, AGP and haptoglobin levels were lower in the high- than
in the low-L-6 group, whereas no significant difference between the two groups
was found in levels of the other positive and negative APPs. TNF-alpha levels
were negatively correlated with transferrin and AHSG levels. No difference in the
levels of positive APPs was observed between patients with low and high TNF-alpha
serum concentration. By contrast, levels of both transferrin and AHSG were
significantly lower in the high- than in the low-TNF-alpha group. CONCLUSIONS:
These findings indicate that, except for regulation of the negative APPs by TNF
alpha, the mechanism of APP regulation is different under the conditions of the
short-term and the chronic, long-lasting 'acute-phase reaction'.
PMID- 9767366
TI - Kjeld Winkler, former Editor-in-Chief, EJCI.
PMID- 9767367
TI - Relative hyperoxaluria, crystalluria and haematuria after megadose ingestion of
vitamin C.
AB - BACKGROUND: Long-term or high-dosage consumption of vitamin C may play a role in
calcium oxalate kidney stone formation. The present study was undertaken to
determine the biochemical and physicochemical risk factors in a male subject who
developed haematuria and calcium oxalate crystalluria after ingestion of large
doses of ascorbic acid for 8 consecutive days. METHODS: Twenty-four-hour urine
samples were collected before and during the ascorbic acid ingestion period as
well as after the detection of haematuria. A special procedure was implemented
for urine collections to allow for oxalate, ascorbate and other urinalysis.
Oxalate was determined in the presence of EDTA to prevent in vitro conversion to
ascorbic acid, whereas ascorbate itself was determined by manual titration in a
redox method using the dye dichlorophenolindophenol. Urinalysis data were used to
compute calcium oxalate relative supersaturations and Tiselius risk indices,
whereas scanning electron microscopy was used to examine urinary deposits.
RESULTS: Oxalate excretion increased by about 350% during ascorbate ingestion
before haematuria. Ascorbate concentrations also increased dramatically but
appeared to reach a plateau maximum. Increasing calcium excretion was accompanied
by decreasing potassium and phosphate values. The calcium oxalate relative
supersaturation and Tiselius risk index increased during vitamin C ingestion and
large aggregates of calcium oxalate dihydrate crystals were observed by scanning
electron microscopy immediately after the detection of haematuria. CONCLUSION:
High percentage metabolic conversion of ascorbate to oxalate in this subject
caused relative hyperoxaluria and crystalluria, the latter manifesting itself as
haematuria. Clinicians need to be alerted to the potential dangers of large dose
ingestion of vitamin C in some individuals.
PMID- 9767365
TI - Investigation into thiol conjugation of transthyretin in hereditary transthyretin
amyloidosis.
AB - BACKGROUND: For all forms of amyloidosis, the amyloid-generating mechanism is
unknown. Familial amyloidotic polyneuropathy type I is caused by a variant
transthyretin (TTR Met-30). As electrospray ionization mass spectrometry (ESI-MS)
discloses both thiol-conjugated and -unconjugated forms of wild-type and variant
TTR, we wanted to investigate the relationship between TTR conjugation and
clinically overt amyloid disease. METHODS: Plasma from 35 individuals (12
symptomatic TTR Met-30 carriers, nine asymptomatic and 14 healthy control
subjects) were analysed using ESI-MS. RESULTS: The total TTR concentration was
significantly lower in symptomatic TTR Met-30 carriers than in control subjects.
An increased percentage of conjugated TTR Met-30 was found in symptomatic
carriers compared with asymptomatic, whereas the percentage conjugated wild-type
TTR was similar for control subjects, asymptomatic and symptomatic TTR Met-30
carriers. CONCLUSION: The finding of a decreased ratio of unconjugated to
conjugated TTR Met-30 in plasma samples from symptomatic TTR Met-30 carriers
indicates that thiol conjugation of TTR could be involved in amyloid formation.
PMID- 9767368
TI - Effects of digoxin and digitoxin on circadian blood pressure profile in healthy
volunteers.
AB - BACKGROUND: The aim of the study was to investigate the potential effects of
chronic digoxin or digitoxin treatment or circadian blood pressure profile in
normotensive subjects. METHODS: In two randomized double-blind, placebo
controlled cross-over protocols, 22 healthy normotensive subjects were enrolled,
12 subjects in either study. After adequate loading doses, digoxin 0.25 mg twice
daily or digitoxin 0.1 mg daily was given for a total of 10 days. Automatic 24-h
ambulatory blood pressure measurements were carried out at days 4 and 10 of
either glycoside or placebo. RESULTS: Digoxin treatment significantly decreased
heart rate (HR) and diastolic blood pressure (DBP) during the overnight sleeping
phase of day 10 compared with placebo (HR, 4 beats min-1; DBP, 8 mmHg; P < 0.05).
Digitoxin treatment significantly decreased heart rate and diastolic blood
pressure during the overnight sleeping phase of day 4 (HR, 8 beats min-1; DBP, 7
mmHg) and day 10 (HR, 7 beats min-1; DBP, 5 mmHg) compared with placebo (P <
0.05). Neither digoxin nor digitoxin significantly affected systolic blood
pressure. CONCLUSIONS: Both digoxin and digitoxin, within therapeutic steady
state plasma concentrations, reduced diastolic blood pressure and heart rate
during overnight sleep, presumably because of increased parasympathetic activity
or decreased sympathetic activity.
PMID- 9767369
TI - Mutations in the carboxy terminus of the beta and gamma subunits of the
epithelial sodium channel are not present in patients with hypertensive crisis.
AB - BACKGROUND: The pathophysiology of hypertensive crises is poorly understood. To
date, no information is available about genetic determinants underlying the
individual risk for development of hypertensive urgencies or emergencies.
Recently, mutations in the beta subunit (h beta ENaC) and the gamma subunit (h
gamma ENaC) of the human epithelial sodium channel (hENaC) have been shown to
result in excessive elevation of blood pressure in patients with Liddle's
syndrome. METHODS: Using polymerase chain reaction and direct sequencing of
amplification products we have screened 90 consecutive out-patients with
hypertensive urgency or hypertensive emergency for the presence of mutations in
the carboxy terminus of these genes. Furthermore, serum potassium concentrations
were determined in all 90 patients, and serum aldosterone levels and plasma renin
activity were measured in a subset of 34 patients. RESULTS: Among 71 patients
with hypertensive urgency (78.9%) and 19 patients with hypertensive emergency
(21.1%) not one individual showed a mutation in genomic DNA extending from codon
532 to codon 637 of h beta ENaC and from codon 525 to codon 651 of h gamma ENaC.
Twelve of 90 patients showed mild hypokalaemia (13.3%), 16 of 34 patients had a
plasma renin activity below the lower normal range (47.1%) and one of 34 patients
had a low serum aldosterone concentration (2.9%). CONCLUSIONS: The present study
clearly demonstrates the absence of mutations in the carboxy terminus of the h
beta ENaC and h gamma ENaC gene of hENaC in an Austrian cohort of 90 patients
suffering from hypertensive crisis.
PMID- 9767370
TI - New type of the internalization-defective low-density lipoprotein receptor owing
to two-nucleotide deletion (2199delCA or 2201delCA) in Japanese patients with
familial hypercholesterolaemia.
AB - BACKGROUND: In mutations of the low-density lipoprotein (LDL) receptor gene, the
defect of internalization is caused by a mutation in the cytoplasmic domain of
the receptor linked with exons 17 and 18, and the O-linked sugar domain linked
with exon 15 has been speculated not to affect the function of the receptor.
Here, we describe a novel mutation of the O-linked sugar domain of the LDL
receptor gene, designated familial hypercholesterolaemia (FH)-Mishima with
Japanese pedigree, which resembles but still differs from classical defective
internalization cases. METHODS: LDL metabolism was examined in cultured skin
fibroblasts from patients. Immunoprecipitation and immunohistochemical techniques
were applied for the detection of the receptor protein size and distribution.
Screening of the mutant exon(s) of the LDL receptor gene was performed using the
polymerase chain reaction-single-strand conformation polymorphism technique (PCR
SSCP), and sequencing of the mutated alleles was carried out using the dideoxy
chain termination method. RESULTS: LDL-binding activity at 4 degrees C in skin
fibroblasts from patients was similar to normal, but that at 37 degrees C with
the ligand decreased time dependently and was lost at 6 h, resulting in the
defect of internalization and degradation of LDL. The receptor protein on the
cell surface was detected at 4 degrees C by IgG-C7, an anti-LDL receptor
antibody, but was not detected after incubation with LDL at 37 degrees C. The
size of the receptor was 112 kD as determined by immunoprecipitation analysis. A
deletion of two nucleotides in exon 15 was detected in the DNA sequence of the
LDL receptor gene. The deletion results in a shift of the reading frame after Thr
713 of the mutant and makes a stop codon at amino acid 759. CONCLUSION: Deletion
of the two nucleotides caused novel amino acid sequences after the O-linked sugar
domain, which has the ability of sorting on the cell membrane at 4 degrees C, but
not at 37 degrees C in vivo, resulting in the complete cessation of activity of
the LDL receptor.
PMID- 9767371
TI - Varying very low-density lipoprotein secretion of rat hepatocytes by altering
cellular levels of calcium and the activity of protein kinase C.
AB - BACKGROUND: Calcium antagonists lower plasma levels of lipoproteins and suppress
hepatic very low-density lipoprotein (VLDL) secretion. Similar effects have been
observed with the calcium ionophore A23187. We studied further the effect of
calcium on VLDL metabolism. METHODS: Hepatocytes from male Wistar rats were
isolated and cultured in the presence or absence of calcium-mobilizing hormones,
or compounds that either stimulate or inhibit the activity of protein kinase C.
Secreted VLDL (d < 1.006 g mL-1) was isolated by centrifugation (145,000 x g),
and lipids and apolipoprotein B were analysed. RESULTS: VLDL secretion reached
maximum in hepatocytes cultured in medium containing calcium 0.8-2.4 mmolL-1.
Depleting the cells of calcium by incubating in calcium-free medium or by
treating the cells with the Ca(2+)-ATPase inhibitor thapsigargin (5 x 10-7 molL
1) suppressed lipid secretion to less than 15% of control, and this was
accompanied by an increase in cellular levels of triacylglycerol. Calcium loading
(medium calcium > 2.4 mmolL-1) suppressed both lipoprotein secretion and cellular
levels of lipids, suggesting a reduced overall rate of lipid synthesis. At an
extracellular calcium concentration of 0.8 mmolL-1, angiotensin II, vasopressin,
endothelin-1 (10(-7) molL-1) or phenylephrine (10(-4) molL-1) suppressed VLDL
secretion (maximum to 37% of control), and elevated medium calcium attenuated
this effect. The protein kinase C inhibitor chelerythrine (5 x 10(-5) molL-1) and
the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) (10(-6) molL
1), suppressed VLDL secretion to 18% and 60% of control, respectively, whereas
the protein kinase C-inactive 4 alpha-PMA was without an effect. No effect on
ketogenesis was observed by these compounds, indicating that suppressed lipid
secretion was not due to an enhanced oxidation of lipids. CONCLUSIONS: Hepatic
VLDL secretion can be related to changes in hepatocyte levels of calcium and the
activity of protein kinase C.
PMID- 9767372
TI - Plasma acylation stimulating protein (ASP) as a predictor of impaired cellular
biological response to ASP in patients with hyperapoB.
AB - BACKGROUND: The objective of this study was to examine specific membrane binding
of [125I]-acylation stimulating protein (ASP) in cultured human skin fibroblasts
obtained from normal subjects and patients with hyperapoB. ASP is a small basic
protein isolated from human plasma that stimulates triglyceride synthesis (TGS)
and glucose transport (GT) in human skin fibroblasts and adipocytes. DESIGN: In
the present study, three groups were studied: normal (NASP-NB) subjects,
hyperapoB subjects with normal plasma ASP (NASP-HB) and hyperapoB subjects with
high plasma ASP (HASP-HB). RESULTS: ASP-induced TGS in fibroblasts from HASP-HB
subjects was significantly less than in the two control groups with normal plasma
ASP (NASP-NB and NASP-HB). Similarly, ASP stimulation of GT was less in HASP-HB
fibroblasts than in the NASP-HB fibroblasts or the NASP-NB subjects. Insulin
induced TGS was similar in all three groups as was insulin-stimulated GT. As
well, protein kinase C-mediated stimulation was equivalent among the three groups
both for GT and for TGS. There was no significant difference in the binding
affinity (Kd) of [125I]-ASP to intact cells in any group. By contrast, binding of
[125I]-ASP revealed a significantly lower Bmax of the HASP-HB cell lines than the
NASP-NB cells and the NASP-HB cells. CONCLUSION: A decrease in the ASP cell
surface receptor concentration is responsible for decreased ASP stimulation of
TGS, and GT and may contribute to the inefficient postprandial triglyceride (TG)
clearance in HASP-HB subjects.
PMID- 9767373
TI - Mutations in the low-density lipoprotein receptor gene in Swedish familial
hypercholesterolaemia patients: clinical expression and treatment response.
AB - BACKGROUND: Familial hypercholesterolaemia, an autosomal co-dominant disorder
caused by defects in the low-density lipoprotein receptor gene, is strongly
associated with premature development of cardiovascular disease. METHODS: In this
study, we have applied a gene screening method in a population of familial
hypercholesterolaemia patients in order to describe the genetic background of the
disease in southern Sweden. These patients were studied with the aim of relating
the presence of the different mutations to the clinical expression of the disease
and to the response to pharmacological treatment. RESULTS: In 16 out of 21
patients, potentially disease-causing low-density lipoprotein receptor gene
defects were found, including five not previously described alterations (C240-
>F, C122-->stop, C356-->Y, 785insG, 165delG). No defects in apolipoprotein B were
found. One group of patients (n = 4) carried the mutation C122-->stop and another
group of patients (n = 4) a mutation causing the substitution W66-->G. Patients
in the two genotype subgroups were very similar with respect to lipid levels
before treatment. CONCLUSION: A tendency towards differential susceptibility to
treatment with statins was observed for the patient groups, encouraging further
comparative studies of heterozygous FH patients.
PMID- 9767374
TI - Monitoring of extracellular matrix metabolism and cross-linking in tissue, serum
and urine of patients with chromoblastomycosis, a chronic skin fibrosis.
AB - BACKGROUND: Chromoblastomycosis is a fungal disease leading to a granulomatous
reaction associated with dermal fibrosis. METHODS: In an attempt to elucidate the
mechanisms leading to improvement in the cutaneous lesions after treatment with
terbinafine, a new antifungal drug, we analysed collagen content and cross
linking before and at the end of the treatment. The turnover of extracellular
matrix was monitored for 1 year by following up serum and urinary metabolites.
RESULTS: The serum levels of type III collagen and its N-terminal propeptide were
correlated with the lesion size (P < 0.035) after 4 and 12 months of treatment
respectively. After 4 months of treatment, urinary pyridinoline was higher (P =
0.04) in patients whose lesion size was reduced by more than 50% and serum
hyaluronan was lower in patients who had lesions active for less than 5 years (P
< 0.05). The treatment increased pyridinoline and pentosidine cross-links in the
lesions but significantly reduced the collagen content (P = 0.05). CONCLUSION:
This is the first demonstration that, in addition to its fungicidal activity,
terbinafine acts in vivo as an antifibrotic drug.
PMID- 9767375
TI - Direct evidence for an increase in thrombopoiesis after liver transplantation.
AB - BACKGROUND: In advanced liver cirrhosis, thrombocytopenia results from
'hypersplenism' due to increased platelet sequestration and platelet 'pooling' in
the enlarged spleen and/or from reduced platelet production in the bone marrow.
We sought to differentiate between these two mechanisms by studying
thrombopoiesis before and after orthotopic liver transplantation by the
determination of reticulated platelets, direct indicators for the thrombopoietic
activity in the bone marrow. METHODS: Reticulated platelets, peripheral platelet
counts, mean platelet volumes and platelet-reactive antibodies were determined in
15 patients suffering from advanced liver cirrhosis before and during an
observation period of 14 days after orthotopic liver transplantation (OLT).
Thrombopoietin levels of ten patients were determined before transplantation and
consecutively for 14 days after surgery. RESULTS: All patients except one were
thrombocytopenic before transplantation (median count 94 x 10(9) L-1, range 69
114 x 10(9) L-1). Although levels of reticulated platelets rose 2 days after
surgery from baseline values of 1.0% (range 0.2-1.6%) to peak values of 4.6%
(range 1.7-17.9%, P < 0.05) on day 6, platelet counts declined during the first 5
days after transplantation. When peripheral platelet counts increased to the
normal range (median day 11, range day 8-33), reticulated platelets were again at
pretransplant levels. Thrombopoietin levels before OLT were within the normal
range (< 85 pg mL-1). On day 5 post surgery, a maximum increase of 5.8-fold
(range 2.2- to 28-fold) over baseline values was observed. Mean platelet volume
did not show any significant deviation from the baseline values and platelet
antibodies could not be detected during the observation period. CONCLUSION: Our
findings provide direct evidence for an increase in de novo platelet production
after orthotopic liver transplantation. As the elevation of reticulated platelets
precedes platelet recovery, it could serve as an early indicator to predict
thrombopoiesis as a result of reconstituted liver function.
PMID- 9767376
TI - Peroxynitrite generation might explain elevated glutamate and aspartate levels in
multiple sclerosis cerebrospinal fluid.
PMID- 9767377
TI - Effect of air pollutants on the pulmonary surfactant system.
AB - Air pollutants have been recognized to influence the structure and function of
the surfactant system. Agents that have received the most attention include
ozone, nitrogen dioxide, hyperoxia, diesel exhaust, tobacco smoke, silica and
fibrous materials such as asbestos. The deleterious effects of air pollutants on
the surfactant system depend on the size of the agent, on its solubility in
aqueous solutions and chemical reactivity and on its concentration and the
duration of exposure. Hereby the following general rules apply: the smaller the
agent's size and the less water soluble the pollutant is, the greater the
tendency to reach the alveoli during breathing. In addition, the reactivity also
determines the depth of penetration into alveoli. Compounds with high reactivity
such as O3, which also fulfil the earlier rules, will react with the upper
respiratory tract compared with compounds with slightly reduced reactivity, such
as NO2, which will penetrate the alveoli. The common consequence of exposure to
air pollutants is an accumulation of surfactant phospholipids and surfactant
specific proteins in the bronchoalveolar lavage fluid. These components also are
structurally altered, mainly by oxidant gases, resulting in impairment of their
biological activity. Thus, for surfactant phospholipids, there is impaired
adsorption to the air-liquid interface due to oxidation of their fatty acids.
Also, surfactant protein A, regarded as a modulator of the surfactant system,
shows impaired functions after exposure to oxidants. It is likely that in
addition to the effects described in this review not all effects are known
because the molecular effects of several key components (e.g. SP-B and C) have
not been well studied.
PMID- 9767378
TI - The association of type II pneumocytes and endothelial permeability with the
pulmonary custocyte system in experimental acute pancreatitis.
AB - BACKGROUND: Pancreatitis-associated pulmonary injury is still associated with
substantial mortality, especially when seen as a part of the multiple organ
dysfunction syndrome. METHODS: The present study aimed at evaluating alterations
in type II pneumocytes and the potential relationship with the development of
pulmonary injury after acute haemorrhagic pancreatitis induced by an intraductal
infusion of 5% sodium taurodeoxycholate in the rat. RESULTS: The results
demonstrated that definite alterations in type II pneumocytes were noted 12 and
24 h after induction of pancreatitis, characterized by an increase in the number
of vocalized lamellae, the exposed area of type II pneumocytes to alveolar
airspace, cellular separation and apoptosis without alterations in cellular
membrane integrity. Dysfunction of the pulmonary endothelial barrier was
evidenced by an increase in pulmonary albumin flux and the leakage index as well
as the migration of lanthanum probes from capillaries to interstitial tissues.
The levels of tumour necrosis factor (TNF) in bronchoalveolar lavage fluid
significantly increased during the initial phase (3 and 6 h) after pancreatitis.
The phagocytic activity of the pulmonary custocyte system increased 3 and 12 h
after induction of pancreatitis. CONCLUSION: Thus, pulmonary endothelial barrier
dysfunction, an activated custocyte system, and initial release of TNF seems to
be involved in the pathogenesis of pancreatitis-associated type II pneumocyte
compromise.
PMID- 9767379
TI - The expression of the glial glutamate transporter protein EAAT2 in motor neuron
disease: an immunohistochemical study.
AB - Emerging evidence suggests that a disturbance of the glutamate neurotransmitter
system may be a contributory factor to motor neuron injury in motor neuron
disease. Previous autoradiographic and immunoblotting studies have suggested that
there may be reduced expression of glutamate transporter proteins in
pathologically affected areas of the CNS in motor neuron disease. This study
further explores the possible alteration in expression of the excitatory amino
acid transporter protein EAAT2 in MND, by examining the protein expression in
situ, in frozen sections, using immunohistochemistry. The aim of the study was to
compare the distribution and density of EAAT2 in the motor cortex and spinal cord
of MND cases (n = 16) compared with neurologically normal controls (n = 12),
matched for relevant parameters. A novel, previously characterized, monoclonal
antibody to EAAT2 was employed. EAAT2 immunoreactivity in motor neuron disease
and control cases was compared using relative optical density measurements
generated by computerized image analysis. In the motor cortex, EAAT2
immunoreactivity was laminated comprising a superficial intense band
(corresponding to layers 1 and 2); a paler middle band (layer 3 and part of 5)
and a more intense deep layer (layers 5 and 6). In the spinal cord, the ventral
horn showed strong immunoreactivity with dense perisomatic staining around motor
neuron cell bodies, the substantia gelatinosa showed moderate diffuse staining
and the intermediate spinal laminae showed weak staining. This general pattern of
immunoreactivity was preserved in the motor neuron disease cases. However, in the
motor neuron disease cases compared with controls, the optical density values for
EAAT2 immunoreactivity were significantly reduced in all grey matter regions of
the lumbar spinal cord (P < 0.001) and were increased in the middle laminae of
the motor cortex (P < 0.05). This study indicates that glutamate transporter
pathology in motor neuron disease may be a more complex phenomenon than
previously recognized.
PMID- 9767380
TI - Human FGF-1 gene delivery protects against quinolinate-induced striatal and
hippocampal injury in neonatal rats.
AB - Fibroblast growth factors (FGFs) are cell mitogens and differentiating factors
with neuroprotective properties in the CNS. We have already shown that
endothelial cells genetically engineered to secrete human FGF-1 (RBEZ-FGF)
survive implantation to neonatal rat brain (Johnston et al. (1996) J. Neurochem.
67, 1643-1652]. In this study, the effects of cell-based FGF-1 gene delivery on
quinolinate-induced neurotoxicity in the developing rat brain were examined.
Control endothelial cells (RBE4), and RBEZ-FGF cells were implanted into right
striatum at post-natal day (PND) 7. On PND 10, quinolinate (150 nmol), an
endogenous N-methyl-d-aspartate (NMDA) receptor agonist, or vehicle alone was
injected into striatum ipsilateral to cell implantation. Injury was quantified in
coronal sections obtained from PND 17 animals by comparing striatal and
hippocampal volumes ipsilateral and contralateral to the site of quinolinate
injection. Human FGF-1 specific transgene expression in vivo was shown by
Northern blot and RT-PCR up to 14 days after cell implantation in control
animals, and up to 4 days after quinolinate exposure. Quinolinate reduced the
size of ipsilateral striatum by 37% and hippocampus by 38% in animals
preimplanted with control endothelial cells. In contrast, quinolinate reduced the
size of striatum by only 14% and had no effect on hippocampal size in animals
preimplanted with RBEZ-FGF cells. Thus, FGF-1 gene delivery protected the
developing striatum and hippocampus from quinolinate-induced volume loss by 62%
and 100%, respectively. Intrastriatal quinolinate resulted in a significant
decrease in density of NOS+ CA3 hippocampal neurons (-38%) without affecting the
density of NOS+ neurons in hippocampal regions CA1, dentate gyrus or striatum.
This response of CA3 NOS+ neurons appeared to be only partially reversed by FGF-1
gene delivery. Our results show that intracerebral FGF-1 gene expression within
the developing brain can protect striatum and hippocampus from quinolinate
mediated injury.
PMID- 9767381
TI - Re-establishment of direct synaptic connections between sensory axons and
motoneurons after lesions of neonatal opossum CNS (Monodelphis domestica) in
culture.
AB - For functional recovery after spinal cord injury, regenerating fibres need to
grow and to reform appropriate connections with their targets. The isolated
central nervous system of neonatal opossums aged 1-9 days has been used to
analyse the precision with which neurons become reconnected during regeneration.
In culture these preparations maintain their electrical activity and show rapid
outgrowth through spinal cord crushes or cuts. By recording electrically and by
staining with horseradish peroxidase, we first demonstrated that direct reflex
connections were already present at birth between sensory fibres in one segment
and motoneurons in the same segment and in adjacent segments. As in previous
experiments, 5 days after the spinal cord had been crushed, labelled sensory
fibres grew across the lesion to reach the next segment (Woodward et al. (1993)
J. Exp. Biol., 176, 77-88; Varga et al. (1995a) Eur. J. Neurosci., 7, 2119-2129,
Varga et al. (1995b) Proc. Natl. Acad. Sci. USA, 92, 10959-10963). Beyond the
lesion the labelled axons abruptly changed direction, traversed the spinal cord
and terminated on labelled motoneurons in the ventral horn. In preparations that
had regenerated dorsal root stimulation once again initiated ventral root
reflexes. Electron micrographs revealed synapses made by labelled sensory axons
on motoneurons. Double staining of growing sensory axons and radial glial fibres
showed close association, suggesting guidance. These results indicate that the
original pathway is re-established during repair and that appropriate connections
are reformed after injury.
PMID- 9767382
TI - Changes in morphology and behaviour of retinal growth cones before and after
crossing the midline of the mouse chiasm - a confocal microscopy study.
AB - The growth of retinal axons was investigated in different regions of the optic
chiasm in C57 pigmented mouse embryos aged embryonic day 13 (E13) to E15.
Individual retinal axons and their growth cones were labelled anterogradely by
DiI and imaged using a confocal imaging system. In aldehyde-fixed embryos,
retinal growth cones display a simple form in the optic nerve and become more
complex in morphology in the chiasm. The complex form is particularly prominent
in those axons that turn to the ipsilateral tract in the premidline region of
chiasm. Moreover, complex growth cones are also commonly found in axons in the
postmidline chiasm, which are markedly different in morphology from those axons
in the premidline region, suggesting that the postmidline chiasm contains a novel
environment for the pathfinding of retinal axons. In another experiment, the
dynamic growth of retinal axons is studied in a brain slice preparation of the
living retinofugal pathway. Retinal axons show an intermittent growth across the
premidline and postmidline chiasm. Extensive remodelling of growth cone form
followed by a shift in growth direction is commonly seen during the pause
periods, indicating that signals that guide axon growth across the chiasm are not
restricted to the midline, but are laid down throughout the chiasm. Moreover,
dramatic changes in axon trajectory are noted first at the premidline chiasm
where the uncrossed axons segregate from the crossed axons, and second at the
postmidline chiasm where specific sorting of retinal axons according to their
position in the dorsal ventral retinal axis and their ages are known to take
place. These results show that there are two distinct environments, separated by
the midline in the chiasm, where axons show different responses to local guidance
cues and develop the distinct fibre orders.
PMID- 9767384
TI - Potentiometric study of resting potential, contributing K+ channels and the onset
of Na+ channel excitability in embryonic rat cortical cells.
AB - Resting membrane potential (RMP), K+ channel contribution to RMP and the
development of excitability were investigated in the entire population of acutely
dissociated embryonic (E) rat cortical cells over E11-22 using a voltage
sensitive fluorescent indicator dye and flow cytometry. During the period of
intense proliferation (E11-13), two cell subpopulations with distinct estimated
RMPs were recorded: one polarized at approximately -70 mV and the other
relatively less-polarized at approximately -40 mV. Ca2+o was critical in
sustaining the RMP of the majority of less-polarized cells, while the well
polarized cells were characterized by membrane potentials exhibiting a
approximately Nernstian relationship between RMP and [K+]o. Analysis of these two
subpopulations revealed that > 80% of less-polarized cells were proliferative,
while > 90% of well-polarized cells were postmitotic. Throughout embryonic
development, the disappearance of Ca2+o-sensitive, less-polarized cells
correlated with the disappearance of the proliferating population, while the
appearance of the K+o-sensitive, well-polarized population correlated with the
appearance of terminally postmitotic neurons, immuno-identified as BrdU-, tetanus
toxin+ cells. Differentiating neurons were estimated to contain increased K+i
relative to less-polarized cells, coinciding with the developmental expression of
Cs+/Ba2+-sensitive and Ca2+-dependent K+ channels. Both K+ channels contributed
to the RMP of well-polarized cells, which became more negative toward the end of
neurogenesis. Depolarizing effects of veratridine, first observed at E11,
progressively changed from Ca2+o-dependent and tetrodotoxin-insensitive to Na+o
dependent and tetrodotoxin-sensitive response by E18. The results reveal a
dynamic development of RMP, contributing K+ channels and voltage-dependent Na+
channels in the developing cortex as it transforms from proliferative to
primarily differentiating tissue.
PMID- 9767383
TI - Dihydrokainate-sensitive neuronal glutamate transport is required for protection
of rat cortical neurons in culture against synaptically released glutamate.
AB - Glutamate transport in nearly pure rat cortical neurons in culture (less than
0.2% astrocytes) is potently inhibited by dihydrokainate, l-serine-O-sulphate,
but not by l-alpha-amino-adipate. This system allows for a test of the hypothesis
that glutamate transport is important for protecting neurons against the toxicity
of endogenous synaptically released glutamate. In support of this hypothesis, a
20-24 h exposure to 1 mm dihydrokainate reduced cell survival to only 14.8 +/-
9.8% in neuronal cultures (P < 0.001; n = 3), although it had no effect on
neuronal survival in astrocyte-rich cultures (P > 0.05; n = 3). Dihydrokainate
also significantly caused accumulation of glutamate in the extracellular medium
of cortical neuronal cultures (6.6 +/- 4.9 micrometer, compared to 1.2 +/- 0.3
micrometer in control, n = 14, P < 0.01). The neurotoxicity of dihydrokainate was
blocked by 10 micrometer MK-801, 10 micrometer tetrodotoxin, and an enzyme system
that degrades extracellular glutamate. The latter two also abolished the
accumulation of glutamate in the extracellular medium. Dihydrokainate (1 mm)
inhibited the 45calcium uptake stimulated by 30 micrometer N-methyl-d-aspartate
(NMDA), but not by higher concentrations consistent with a weak antagonist action
of dihydrokainate at the NMDA receptor. Whole cell recordings showed that 1 mm
dihydrokainate produced approximately 25% inhibition of 30 micrometer NMDA
induced current in cortical neurons. Dihydrokainate (1 mm) alone generated a
small current (17% of the current produced by 30 micrometer NMDA) that was
blocked by 30 micrometer 5,7-dichlorokynurenate and only weakly by 10 micrometer
cyano-7-nitroquinoxaline-2,3-dione (CNQX). These results suggest that the
toxicity of dihydrokainate in neuronal cultures is due to its ability to block
glutamate transport in these cultures, and that dihydrokainate-sensitive neuronal
glutamate transport may be important in protecting neurons against the toxicity
of synaptically released glutamate.
PMID- 9767385
TI - Two types of TTX-resistant and one TTX-sensitive Na+ channel in rat dorsal root
ganglion neurons and their blockade by halothane.
AB - The clinically employed general anaesthetic halothane was shown to exert action
on the peripheral nervous system by suppressing spinal reflexes, but it is still
unclear which mechanisms underlie this action. The present study addressed the
question whether blockade of tetrodotoxin-sensitive (TTXs) and -resistant (TTXr)
Na+-channels in rat dorsal root ganglia (DRG) neurons by halothane could explain
its peripheral effects. Two types of TTXr Na+-currents, fast and slow, with
distinct activation and inactivation kinetics were found in small (< 25
micrometer) and medium sized (25-40 micrometer) DRG neurons. These currents were
blocked by halothane with IC50 values of 5.4 and 7.4 mmol/L, respectively.
Additionally, in a concentration-dependent manner halothane accelerated the
inactivation kinetics of both currents and shifted the inactivation curves to
more hyperpolarized potentials. Neither the activation curves of both TTXr Na+
currents were influenced by halothane nor a voltage-dependent block at test
potentials of the currents was seen. In contrast to that of fast current, the
time-to-peak for slow current was changed in the presence of halothane. The TTXs
Na+-current which prevailed in large neurons (> 40 micrometer) was blocked by
halothane with an IC50 of 12.1 mmol/L. Its inactivation curve was also shifted to
more hyperpolarized potentials and the inactivation kinetics accelerated with
increasing halothane concentration. Similarly to TTXr Na+-currents, the
activation curve of TTXs Na+-current and its time-to-peak were not influenced by
halothane. It is suggested that two types of TTXr Na+-currents can explain the
heterogeneity in kinetic data for TTXr Na+-currents. Furthermore, the incomplete
blockade of Na+-currents might underlie the incomplete reduction of spinal
reflexes at clinically used concentrations of halothane.
PMID- 9767386
TI - Influence of Gz and Gi2 transducer proteins in the affinity of opioid agonists to
mu receptors.
AB - The affinity displayed by different opioids to mu receptors (ORs) was determined
in mouse brain membranes incubated with antibodies directed to Galpha subunits of
the guanine nucleotide-binding proteins Gi2 and Gz. Assays were conducted with 10
pm 125I-Tyr27-beta-endorphin in the presence of 300 nm N, N-diallyl-Tyr-(alpha
aminoisobutyric acid)2-Phe-Leu-OH (ICI-174 864), which prevented the binding of
the iodinated neuropeptide to delta-ORs. Gpp(NH)p or the preincubation of mouse
brain membranes with IgGs to Gi2alpha or Gzalpha subunits, promoted reductions in
the affinity exhibited by the labelled probe. The potencies of beta-endorphin, [D
Ala2,N-MePhe4,Gly-ol5]-enkephalin (DAMGO) and [D-Pen2,5]enkephalin (DPDPE) were
reduced after impairing the coupling of mu-ORs to Gi2 or Gz proteins. Morphine
showed a loss of affinity towards the mu-OR after preincubation of membranes with
IgGs to Gzalpha subunits. However, it retained its potency after treatment with
the anti-Gi2alpha IgGs. Conversely, [D-Ala2, D-Leu5]enkephalin (DADLE) and [D
Ser2, Leu5] enkephalin-Thr6 (DSLET) showed decreased affinity to mu-ORs after
treatment with anti-Gi2alpha IgGs, with no noticeable change following the use of
IgGs to Gzalpha subunits. The affinity exhibited by the opioid antagonists
naloxone, naltrexone, naloxonazine and [Cys2,Tyr3,Orn5, Pen7 amide]somatostatin
analogue (CTOP) remained unchanged after either treatment. Therefore, the
affinity exhibited by opioid agonists of mu-ORs, but not antagonists, depends on
the nature of the G-protein coupled to these receptors.
PMID- 9767387
TI - Associative and limbic regions of monkey striatum express high levels of dopamine
D3 receptors: effects of MPTP and dopamine agonist replacement therapies.
AB - The role of the dopamine D3 receptor subtype in the central nervous system is
still not well understood. It has a distinct and restricted distribution, mostly
associated with limbic territories of the striatum (olfactory tubercle and the
shell of nucleus accumbens) in rat brain. Dopaminergic denervation induced by a 6
hydroxydopamine lesion of the nigrostriatal system in rat down-regulates the
expression of the D3 receptor. In the present study, we investigated the
functional neuroanatomy of the dopamine D3 receptor subtype in the monkey (Macaca
fascicularis) basal ganglia. We also studied the effect of administration of the
dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and
chronic D1-like (SKF 82958) or D2-like (cabergoline) agonist treatments on
dopamine D3 receptor levels using receptor autoradiography. Our results clearly
show that the distribution of D3 receptors in the monkey is more closely related
to associative and limbic components of the striatum (caudate-putamen), as
compared with its sensorimotor counterpart. Hence, D3 receptors may be more
specifically involved in cognitive and motivational aspects of striatal
functions, which are elaborated in prefrontal, temporal, parietal, cingulate and
limbic cortices. Moreover, MPTP administration significantly decreased levels of
D3 receptors and this effect was reversed or compensated by a chronic treatment
with a D1-like, but not a D2-like, receptor agonist. The D3 receptor may
represent an important target for adjunct or direct therapy designed to improve
cognitive deficits observed in patients with Parkinson's disease, schizophrenia
and other illnesses with frontal lobe cognitive disturbances.
PMID- 9767388
TI - Intracellular Ca2+ during metabolic activation of KATP channels in spontaneously
active dorsal vagal neurons in medullary slices.
AB - Intracellular Ca2+ ([Ca2+]i) and membrane properties were measured in fura-2
dialysed dorsal vagal neurons (DVN) spontaneously active at a frequency of 0.5-5
Hz. [Ca2+]i increased by about 30 nm upon rising spike frequency by more than
200% due to 20-50 pA current pulses or 10 micrometer serotonin. It fell by 30 nm
upon block of spiking by current-injection, tetrodotoxin or Ni2+ and also during
hyperpolarization due to gamma-aminobutyric acid or opening of adenosine
triphosphate (ATP) -sensitive K+ (KATP) channels with diazoxide. KATP channel
mediated hyperpolarizations during anoxia or cyanide produced an initial [Ca2+]i
decrease which reversed into a secondary Ca2+ rise by less than 100 nm. Similar
moderate rises of [Ca2+]i were observed during block of aerobic metabolism under
voltage-clamp as well as in intact cells, loaded with fura-2 AM. The magnitude of
the metabolism-related [Ca2+]i transients did not correlate with the amplitude of
the KATP channel-mediated outward current. [Ca2+]i did not change during
diazoxide-induced or spontaneous activation of KATP outward current observed in
10% of cells after establishing whole-cell recording. Increasing [Ca2+]i with
cyclopiazonic acid did not activate KATP channels. [Ca2+]i was not affected upon
block of outward current with sulphonylureas, but these KATP channel blockers
were effective to reverse inhibition of spike discharge and, thus, the initial
[Ca2+]i fall upon spontaneous or diazoxide-, anoxia- and cyanide-induced KATP
channel activation. A sulphonylurea-sensitive hyperpolarization and [Ca2+]i fall
was also revealed in the early phase of iodoacetate-induced metabolic arrest,
whereas after about 20 min, occurrence of a progressive depolarization led to an
irreversible rise of [Ca2+]i to more than 1 micrometer. The results indicate that
KATP channel activity in DVN is not affected by physiological changes of
intracellular Ca2+ and the lack of a major perturbance of Ca2+ homeostasis
contributes to their high tolerance to anoxia.
PMID- 9767389
TI - Absence of short-wavelength sensitive cones in the retinae of seals (Carnivora)
and African giant rats (Rodentia).
AB - Most non-primate mammals have two types of cone: short-wavelength sensitive (S)
and middle-to-long-wavelength sensitive (M/L) cones. In two species of African
giant rats, Cricetomys gambianus and C. emini, and in two species of earless
seals, Phoca hispida and P. vitulina, the retinal cone types and cone
distributions were assessed with antibodies specific for the M/L-cone opsin and
the S-cone opsin, respectively. All four species were found to completely lack S
cones, while M/L-cones were present in low densities. M/L-cone densities, rod
densities and cone/rod ratios were determined across the retina. Cone proportions
are about 0.3-0. 5% in C. gambianus, 0.5-0.8% in C. emini, and 1.5-1.8% in P.
hispida. An absence of S-cones has previously been reported in a few nocturnal
mammals. As earless seals are visually active during night and day, we conclude
that an absence of S-cones is not exclusively associated with nocturnality. The
functional and comparative aspects are discussed.
PMID- 9767390
TI - Quinolinic acid-induced inflammation in the striatum does not impair the survival
of neural allografts in the rat.
AB - It has been suggested that inflammation related to intracerebral transplantation
surgery can affect the survival of intrastriatal neural allografts. To test this
hypothesis, we transplanted dissociated embryonic mesencephalic tissue from one
of two rat strains, Lewis (allogeneic grafts) or Sprague-Dawley (syngeneic
grafts), to the striatum of Sprague-Dawley rats. The target striatum was either
intact or had received a local injection of quinolinic acid 9 days earlier, in
order to induce a marked inflammation. At 6 or 12 weeks after transplantation,
there was no significant difference between the different groups regarding the
number of surviving grafted tyrosine hydroxylase immunoreactive neurons. However,
the graft volume of both the syngeneic and allogeneic implants was significantly
larger in the quinolinate-lesioned than in the intact striatum. There were
dramatically increased levels of expression of major histocompatibility complex
class I and II antigens, marked infiltrates of macrophages, activated microglia
and astrocytes, and accumulation of large numbers of CD4 and CD8 positive T
lymphocytes in the quinolinate-lesioned striatum. In contrast, these
immunological markers were much less abundant around both syngeneic and
allogeneic grafts placed in intact striatum. We conclude that severe inflammation
caused by quinolinic acid does not lead to rejection of intrastriatal neural
allografts.
PMID- 9767391
TI - Differential expression of alternative splice variants of beta-arrestin-1 and -2
in rat central nervous system and peripheral tissues.
AB - Members of arrestin/beta-arrestin protein family are thought to participate in
agonist-mediated desensitization of G-protein-coupled receptors, including
rhodopsin and beta2-adrenergic receptor. Unlike in human and cow, splice variants
of this protein family in rat have not been studied extensively, and there has
been no report on their existence at protein level. Hence, a previous report by
others on the localization of both beta-arrestin-1 and -2 in a wide range of
innervated rat tissues could imply their broad receptor specificity. In this
report we show the presence of two alternatively spliced forms of beta-arrestin-1
in several rat tissues using both reverse transcription-polymerase chain reaction
and Western immunoblot. Splicing of beta-arrestin-1 pre-mRNA appears to be
subject to differential regulation between the rat CNS and peripheral tissues. In
contrast, we detected no splice variants of beta-arrestin-2 in rat. A comparison
of the genomic DNA sequences of bovine and rat beta-arrestin-2, where the
splicing of bovine beta-arrestin-2 mRNA has been reported, revealed a high degree
of homology in their organization of exons and introns as well as certain
differences that might be responsible for the different processing of beta
arrestin-2 mRNA in the two species. Our two-dimensional isoelectric focusing gels
using rat spinal cord and heart tissues demonstrate isoelectric heterogeneity of
rat beta-arrestin-1, suggesting that beta-arrestin-1 is subject to post
translational modification unlike beta-arrestin-2.
PMID- 9767392
TI - Presynaptic protein interactions in vivo: evidence from botulinum A, C, D and E
action at frog neuromuscular junction.
AB - The present study examines the paralytic action of botulinum neurotoxins at their
natural target, the neuromuscular junction. We asked whether syntaxin,
synaptosome-associated protein of 25 kDa (SNAP-25) and vesicle-associated
membrane protein (VAMP/synaptobrevin), the proteins proteolysed by botulinum, are
susceptible to cleavage in frog nerve terminals, and whether they form complexes
in vivo. In control terminals, the three SNAREs were distributed in broad bands
at 1 micrometer intervals, at sites consistent with presynaptic Ca2+ channels.
Within 3 h, botulinum A, C, D and E (BoNT/A/C/D/E) blocked nerve-evoked muscle
contractions but their effects on substrate immunoreactivity varied. The effect
of BoNT/A on either C-terminus or N-terminus immunoreactivity of SNAP-25 was
undetectable after 3-h incubation, although C-terminus immunoreactivity was
reduced after 24 h; N-terminus immunoreactivity was not affected even after 36 h.
BoNT/E reduced C-terminus immunoreactivity of SNAP-25 1.5 h after toxin
application when transmitter release was blocked, but required 24 h to reduce N
terminus immunoreactivity. BoNT/C reduced syntaxin immunoreactivity after 24-h
incubation but did not affect SNAP-25. BoNT/D reduced VAMP immunoreactivity at 3
h while it increased SNAP-25 C-terminal staining fourfold. BoNT/A and BoNT/C
applied together for 24 h reduced syntaxin immunoreactivity and that of both C-
and N-terminus of SNAP-25, indicating that retention of SNAP-25 N-terminus after
cleavage by BoNT/A depended on intact syntaxin. Therefore, we infer that SNAP-25
interacts with VAMP and with syntaxin in vivo. Neurotoxin action abolished only
40-60% of SNAP-25, VAMP or syntaxin immunoreactivity suggesting that distinct
pools of these proteins, not immediately involved in triggered exocytosis, are
resistant to proteolysis.
PMID- 9767393
TI - The layout of orientation and ocular dominance domains in area 17 of strabismic
cats.
AB - In the primary visual cortex of strabismic cats, the elimination of correlated
activity between the two eyes enhances the segregation of the geniculocortical
afferents into alternating ocular dominance domains. In addition, both tangential
intracortical fibres and neuronal synchronization are severely reduced between
neurons activated by different eyes. Consequently, ocular dominance columns
belonging to different eyes are functionally rather independent. We wondered
whether this would also affect the organization of orientation preference maps.
To this end, we visualized the functional architecture of area 17 of strabismic
cats with both optical imaging based on intrinsic signals and double labelling of
orientation and ocular dominance columns with [14C]2-deoxyglucose and
[3H]proline. As expected, monocular iso-orientation domains had a patchy
appearance and differed for the two eyes, leading to a clear segregation of the
ocular dominance domains. Comparison of 'angle maps' revealed that orientation
domains exhibit a pinwheel organization as in normally reared cats.
Interestingly, the map of orientation preferences did not show any breaks at the
borders between ocular dominance columns: iso-orientation domains were continuous
across these borders. In addition, iso-orientation contours tended to cross the
borders of adjacent ocular dominance columns at right angles. These data suggest
that the basic relations between the layout of orientation maps and ocular
dominance columns are not disturbed by artificial decorrelation of binocular
input. Therefore in cat area 17, the orientation map does not seem to be modified
by experience-dependent changes of thalamic input connections. This suggests the
possibility that use-dependent rearrangement of geniculocortical afferents into
ocular dominance columns is due to Hebbian modifications whereby postsynaptic
responsivity is constrained by the scaffold of the orientation map.
PMID- 9767394
TI - Axonal injury and peripheral nerve grafting in the thalamus and cerebellum of the
adult rat: upregulation of c-jun and correlation with regenerative potential.
AB - The protooncogene c-jun is highly expressed for long periods in axotomized PNS
neurons. This may be related to their growth and regeneration. In contrast,
axotomized CNS neurons show only a small and transient upregulation of c-jun. It
has been suggested that there may be a correlation between this failure to
maintain high levels of c-jun expression after axotomy and abortive CNS axonal
regeneration. We have studied, by in situ hybridization and immunohistochemistry,
the c-jun response after stab wound lesion, and after peripheral nerve grafting
in the thalamus and cerebellum of the adult rat. A lesion elicits upregulation of
c-jun in thalamic neurons ipsilateral to the lesion. This is most evident and
prolonged in neurons such as those of the thalamic reticular nucleus, which have
an established propensity to regenerate. After peripheral nerve grafting, the c
jun response in thalamic neurons is enhanced, mostly in neurons which have axons
regenerating along the grafts. These neurons also upregulate growth-associated
protein 43 (GAP-43). By comparison, injured Purkinje cells of the cerebellum
which do not regenerate their axons along a graft, do not upregulate either c-jun
or GAP-43, although they increase their expression of p75. Thus CNS neurons able
to regenerate their axons along a peripheral nerve graft are those in which c-jun
is induced after injury, and c-jun may play a critical role in the control of
gene programs for axonal regeneration. Moreover, the observed differences in the
ability of CNS neurons to regenerate their axons may relate to a difference in
their intrinsic molecular response to axotomy.
PMID- 9767395
TI - Spatial-frequency tuning and geniculocortical projections in the visual cortex
(areas 17 and 18) of the pigmented ferret.
AB - We have examined the spatial-frequency selectivity of neurons in areas 17 and 18
of the adult pigmented ferret, by measuring how the amplitude of response depends
on the spatial-frequency of moving sinusoidal gratings of optimal orientation and
fixed contrast. Neurons in area 17 of the ferret respond optimally to low spatial
frequencies [average 0.25 cycles per degree (c/deg)], much lower than the optima
for cat area 17. The tuning curves are of the same form as those found in cat and
monkey: unimodal with bandwidths in the range 0.8-3.5 octaves. Neurons in area 18
of the ferret respond optimally to even lower spatial frequencies (average 0.087
c/deg) than area 17 neurons, and the distributions of optimal spatial frequency
for areas 17 and 18 hardly overlap. In both cortical areas, the bandwidth of the
tuning curves is inversely correlated with optimal spatial frequency. This marked
difference in tuning between the two cortical areas is probably attributable to
differential geniculo-cortical projections. Small injections of fluorescent latex
microspheres or horseradish peroxidase (HRP) were made into area 17 or area 18 in
order to investigate the populations of geniculate neurons projecting to the two
cortical areas. After injections into area 17, labelled neurons are found
predominantly in the geniculate A layers, with a few neurons labelled in the C
layers. Conversely, after an area 18 injection, similar numbers of labelled
neurons are found in the C layers as in the A layers. Soma-size analysis of the
neurons in the A-layers suggests the existence of two populations of relay
neurons, which project differentially to areas 17 and 18. The different
geniculate inputs and the different spatial-frequency tuning in areas 17 and 18
may imply that the two cortical areas process visual information more in parallel
than in series.
PMID- 9767396
TI - Learning-specific, time-dependent increases in hippocampal Ca2+/calmodulin
dependent protein kinase II activity and AMPA GluR1 subunit immunoreactivity.
AB - Ca2+/calmodulin-dependent protein kinase II (CAMK II) and one of its target,
alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), glutamate
receptors have been shown to participate in both long-term potentiation (LTP) in
the hippocampus, and in spatial, as well as in a variety, of learning paradigms.
Recently, we were able to demonstrate that the intrahippocampal infusion of a
specific inhibitor of CAMK II (KN62) provoked full retrograde amnesia of an
inhibitory avoidance learning in rats when given immediately, but not 120 or 240
min, after training. Furthermore, this task is accompanied by a rapid, selective
and reversible increase in hippocampal [3H] AMPA receptor binding. Here we report
the effect of this aversively motivated learning task on CAMK II activity, and
AMPA GluR1 subunit phosphorylation and immunoreactivity in the hippocampus. One
trial inhibitory avoidance training is associated with a learning-specific, time
dependent increase (25-78%) in both total and Ca2+-independent activities of CAMK
II in the hippocampus of rats killed immediately (0 min), but not 120 min, after
training. In addition, immunoblotting experiments showed an increment in the
amount of the alpha-subunit of CAMK II at 0, 30 and 120 min after training. An
increase in the in vitro phosphorylation of alpha- and beta-subunits of CAMK II
was also observed in hippocampal synaptosomal membranes (SPM) of trained rats
killed immediately and 30 min post-training. In addition, inhibitory avoidance is
accompanied by a 20% increase in GluR1 phosphorylation and a 33% increase in
GluR1 immunoreactivity 120 min after training. No significant changes were
observed in shocked animals. Phosphorylation of hippocampal SPM from naive
control animals in conditions suitable for CAMK II activation resulted in a large
increase in the density of [3H] AMPA binding (+ 100%). Taken together, these
findings confirm and extend previous data suggesting that CAMK II and AMPA
glutamate receptors in the hippocampus participate in the early phase of memory
formation of an inhibitory avoidance learning.
PMID- 9767397
TI - An animal model of autism: behavioural studies in the GS guinea-pig.
AB - Autism is a human behavioural pathology marked by major difficulties in abnormal
socialization, language comprehension and stereotypic motor patterns. These
behavioural abnormalities have been associated with corticocerebral and
cerebellar abnormalities in autistic patients, particularly in vermal folia VI
and VII. Progress in understanding this disease has been hindered by the absence
of a non-primate animal model. GS guinea-pigs are a partially inbred, non-ataxic
guinea-pig strain with cerebellar and corticocerebral abnormalities similar to
those reported to exist in human patients with autism. In order to determine if
GS guinea-pigs represent an animal model of autism, their behaviour was compared
with that of Hartley strain guinea-pigs. GS animals learned a motor task
significantly more rapidly than Hartley guinea-pigs, but performed it in a more
stereotypic manner and were less influenced by environmental stimuli than
Hartleys. GS animals exhibited significantly less exploratory behaviour in a
novel environment and were significantly less responsive to 50-95 dBA pure tones
than Hartley guinea-pigs. In a social interaction assay, GS guinea-pigs
interacted significantly less frequently with each other or with Hartley guinea
pigs than Hartleys did under the same conditions. GS behaviour thus exhibits
autistic-like behaviour patterns: motor stereotypy, lack of exploration and
response to environment and poor social interaction. Coupled with the
neuropathological findings, this abnormal behaviour suggests that GS guinea-pigs
could be a useful animal model of autism.
PMID- 9767398
TI - 5HT1A-receptors and behaviour under chronic stress: selective counteraction by
testosterone.
AB - Behaviour of chronically stressed male tree shrews is characterized by a
reduction in scent marking, self-grooming and overall locomotor activity. It has
been proposed that this subordination behaviour is related to the down-regulation
of 5HT1A-receptors occurring in distinct brain regions of the animals. The high
cortisol concentrations which accompany chronic stress are supposed to induce
5HT1A-receptor down-regulation. Because chronic stress in males also decreases
androgen levels we investigated whether behaviour and 5HT1A-receptor expression
could be renormalized by testosterone replacement. Male tree shrews were
submitted to subordination stress for 28 days, while during the last 18 days, one
group was treated with testosterone and one with vehicle. Scent marking, self
grooming, and overall locomotor activity were monitored, and cortisol levels were
measured in morning urine during the whole experiment. Brain 5HT1A-receptors were
quantified by in vitro receptor autoradiography. Although in subordinate animals
cortisol levels remained high during the testosterone treatment, 5HT1A-receptors
in the hippocampal formation and the occipital cortex were renormalized to
control levels by the androgen, but 5HT1A-receptors in the ventromedial thalamic
nucleus did not return to base line levels. Scent marking and self-grooming
behaviour were both renormalized by testosterone, but overall locomotor activity
did not return to base line levels. These data indicate that a balance between
glucocorticoids and androgens is necessary to maintain 'normal' numbers of the
monoamine receptors. The fact that both, 5HT1A-receptors and certain behaviours
can be renormalized by the sex steroid supports the view that 5HT1A-receptor are
involved in the regulation of stress behaviour. However, the fact that overall
locomotor activity was not returned to baseline indicates that different types of
behaviour are distinctly regulated.
PMID- 9767399
TI - L-DOPA-induced dyskinesia in the rat is associated with striatal overexpression
of prodynorphin- and glutamic acid decarboxylase mRNA.
AB - Rats sustaining unilateral near-complete 6-hydroxydopamine lesions of the
mesostriatal dopamine pathway received daily injections of 3, 4 dihydroxyphenyl-l
alanine (L-DOPA, 8 mg/kg plus 15 mg/kg benserazide) for 3 weeks. During this
period, about 50% of the rats gradually developed abnormal involuntary movements,
lasting for 2-3 h following each L-DOPA dose. Rats were killed 3 days after the
last L-DOPA injection, and sections through the striatum were processed for in
situ hybridization histochemistry. Within the L-DOPA-treated group, levels of
preproenkephalin (PPE) mRNA, glutamic acid decarboxylase (GAD67) mRNA, and
prodynorphin (PDyn) mRNA in the dopamine-denervated caudate-putamen, as well as
GAD67 mRNA expression in the globus pallidus ipsilateral to the 6-hydroxydopamine
(6-OHDA) lesion, were higher in dyskinetic than non-dyskinetic animals, and
positively correlated with the rats' dyskinesia scores. By contrast, striatal
preprotachykinin mRNA expression and D2 receptor-radioligand binding were not
significantly associated with dyskinesia. Among all these markers, PDyn mRNA
levels showed the most pronounced treatment-dependence (three times higher in the
L-DOPA-treated group than in saline-injected lesion-only controls), and the
strongest correlation with the rats' dyskinesia scores (r2 = 0.82). However, a
multiple regression equation including the three factors, GAD67 mRNA levels in
the GP, GAD67 mRNA in the lateral CPu, and striatal PDyn mRNA, gave a better fit
for dyskinesia scores than PDyn mRNA alone (r2 = 0.92). The results show that L
DOPA-induced dyskinesia is associated with overexpression of PDyn and GAD67 mRNA
in the striatal projection neurons, and GAD67 mRNA levels in the globus pallidus.
Due to its treatment-dependent expression, and strong correlation with the
associated dyskinetic symptoms, striatal PDyn mRNA, in particular, may play a
role in the mechanisms of behavioural sensitization brought about by the drug.
PMID- 9767400
TI - The cytokine network of wallerian degeneration: IL-10 and GM-CSF.
AB - Wallerian degeneration (WD) is the inflammatory response of peripheral nerves to
injury. Evidence is provided that granulocyte macrophage colony stimulating
factor (GM-CSF) contributes to the initiation and progression of WD by activating
macrophages and Schwann, whereas IL-10 down-regulates WD by inhibiting GM-CSF
production. A significant role of activated macrophages and Schwann for future
regeneration is myelin removal by phagocytosis and degradation. We studied the
timing and magnitude of GM-CSF and IL-10 production, macrophage and Schwann
activation, and myelin degradation in C57BL/6NHSD and C57BL/6-WLD/OLA/NHSD mice
that display normal rapid-WD and abnormal slow-WD, respectively. We observed the
following events in rapid-WD. The onset of GM-CSF production is within 5 h after
injury. Production is steadily augmented during the first 3 days, but is
attenuated thereafter. The onset of production of the macrophage and Schwann
activation marker Galectin-3/MAC-2 succeeds that of GM-CSF. Galectin-3/MAC-2
production is up-regulated during the first 6 days, but is down-regulated
thereafter. The onset of myelin degradation succeeds that of Galectin-3/MAC-2,
and is almost complete within 1 week. IL-10 production displays two phases. An
immediate low followed by a high that begins on the fourth day, reaching highest
levels on the seventh. The timing and magnitude of GM-CSF production thus enable
the rapid activation of macrophages and Schwann that consequently phagocytose and
degrade myelin. The timing and magnitude of IL-10 production suggest a role in
down-regulating WD after myelin is removed. In contrast, slow-WD nerves produce
low inefficient levels of GM-CSF and IL-10 throughout. Therefore, deficient IL-10
levels cannot account for inefficient GM-CSF production, whereas deficient GM-CSF
levels may account, in part, for slow-WD.
PMID- 9767401
TI - GABA-dependent generation of ectopic action potentials in the rat hippocampus.
AB - Intracellular recordings from CA3 pyramidal cells of rat hippocampus in a slice
preparation revealed the occurrence of interictal epileptiform discharges and
synchronous GABA-mediated potentials during application of 4-aminopyridine (4AP,
50 micrometer). The synchronous GABA-mediated potential consisted of a sequence
of early hyperpolarization, long-lasting depolarization (LLD), and late
hyperpolarization. Action potentials of variable amplitude occurred at the peak
of the early hyperpolarization and during the LLD rising phase (48 of 64 cells);
they were not prevented by membrane hyperpolarization and displayed inflections
that were reminiscent of the initial segment-somatodendritic (IS-SD)
fractionation. Interictal discharges were blocked by excitatory amino acid
receptor antagonists, while both GABA-mediated potentials and action potentials
of variable amplitude continued to occur (n = 10). The latter events were still
recorded in the presence of the GABAB receptor antagonist CGP-35348 (0.5-1 mm, n
= 4), but were abolished by the GABAA receptor antagonist bicuculline methiodide
(BMI, 10 micrometer, n = 5). Localized application of BMI (20 micrometer, n = 6)
or tetrodotoxin (TTX, 5 micrometer, n = 3) to the CA1 stratum radiatum blocked
the variable amplitude action potentials; these effects were not seen when BMI (n
= 4) or TTX (n = 4) were applied to the CA3 stratum radiatum, although both
procedures made LLDs disappear. Our findings indicate that action potentials of
variable amplitude recorded from CA3 pyramidal cells in the 4AP model are
generated at or near the terminal region of the Schaffer collaterals and that
they represent TTX-sensitive ectopic events. These action potentials are
generated at this site by a BMI-sensitive (and thus GABAA-mediated) mechanism. We
propose that the ectopic action potentials reflect an increased excitability of
axon terminals that is presumably caused by [K+]o elevations associated with the
4AP-induced synchronous GABA-mediated potential.
PMID- 9767402
TI - Differential acetylcholine and GABA release from cultured chick retina cells.
AB - In the present work we investigated the mechanisms controlling the release of
acetylcholine (ACh) and of gamma-aminobutyric acid (GABA) from cultures of
amacrine-like neurons, containing a subpopulation of cells which are
simultaneously GABAergic and cholinergic. We found that 81.2 +/- 2.8% of the
cells present in the culture were stained immunocytochemically with an antibody
against choline acetyltransferase, and 38.5 +/- 4.8% of the cells were stained
with an antibody against GABA. Most of the cells containing GABA (87.0 +/- 2.9%)
were cholinergic. The release of acetylcholine and GABA was mostly Ca2+
dependent, although a significant release of [3H]GABA occurred by reversal of its
transporter. Potassium evoked the Ca2+-dependent release of [3H]GABA and
[3H]acetylcholine, with EC50 of 31.0 +/- 1.0 mm and 21.6 +/- 1.1 mm,
respectively. The Ca2+-dependent release of [3H]acetylcholine was significantly
inhibited by 1 micrometer tetrodotoxin and by low (30 nm) omega-conotoxin GVIA
(omega-CgTx GVIA) concentrations, or by high (300 nm) nitrendipine (Nit)
concentrations. On the contrary, the release of [14C]GABA was reduced by 30 nm
nitrendipine, or by 500 nm omega-CgTx GVIA, but not by this toxin at 30 nm. The
release of either transmitters was unaffected by 200 nm omega-Agatoxin IVA (omega
Aga IVA), a toxin that blocks P/Q-type voltage-sensitive Ca2+ channels (VSCC).
The results show that Ca2+-influx through omega-CgTx GVIA-sensitive N-type VSCC
and through Nit-sensitive L-type VSCC induce the release of ACh and GABA.
However, the significant differences observed regarding the Ca2+ channels
involved in the release of each neurotransmitter suggest that in amacrine-like
neurons containing simultaneously GABA and acetylcholine the two
neurotransmitters may be released in distinct regions of the cells, endowed with
different populations of VSCC.
PMID- 9767403
TI - Influence of handedness on peripheral auditory asymmetry.
AB - It is well established that in humans many differences between right- and left
handers, anatomical, physiological and functional, exist. Left- and mixed
handedness is associated with greater bihemispheric representation of cognitive
functions than in right-handers. Several studies indicate a left-right asymmetry
in the function of hearing pathways between cochlea and auditory cortex, and
furthermore, that this asymmetry is associated with handedness. Our investigation
focuses on the medial olivo-cochlear system, which has been demonstrated to be
more effective in the right than left ear in right-handers. The aim of the study
was to investigate this auditory efferent system asymmetry according to
handedness, gender, eyedness, footedness and the presence of spontaneous
otoacoustic emissions. The medial efferent system has been found to be more
effective in the right than left ear in right-handers, while functioning
symmetrically in left-handers. Furthermore, the olivo-cochlear system, assumed to
be involved in basic language processing, shows an asymmetrical pattern of
functioning influenced by handedness as well as by hemispheric language
representation. Reverse medial efferent system asymmetry was observed in left
handers compared to that in right-handers, on condition that only left-handed
males were considered, or that the left-handers were also left-eyed, or that
spontaneous otoacoustic emissions were present in the left ear of the left
handers, or when only left-handers without mixed-handers were considered.
PMID- 9767404
TI - Short communication: hippocampal neuronal activity and imprinting in the behaving
domestic chick.
AB - The hippocampus of the chick projects to the intermediate and medial part of the
hyperstriatum ventrale (IMHV) which stores information acquired through the
learning process of imprinting. We have investigated whether the response
properties of hippocampal neurons are similar to those of IMHV neurons. Chicks
were imprinted by exposure, one group (n = 7) to a rotating red box (RB), the
other (n = 5) to a rotating blue cylinder (BC). Four chicks were untrained. The
following day, when the chicks were approximately 48 h old, neuronal activity was
recorded in the left hippocampus. The proportion of neurons responding to the RB
and that to the BC in untrained chicks were compared with the proportions in
trained birds. (i) In RB-trained chicks both the proportion responding to the RB
and that to the BC were significantly increased. (ii) In BC-trained chicks no
significant effect on these proportions was found. Of the responsive neurons some
were colour (red or blue) sensitive and others were shape (box or cylinder)
sensitive; the proportions so responsive were not influenced by training
condition. Certain neurons responded significantly differently when a stimulus
was 0.5 m or 2 m from the chick (35%; d-sensitive); very few neurons were
equivalently responsive to a stimulus at both distances (3%; d-invariant). These
proportions were not significantly affected by training condition. Hippocampal
responses are compared with those in the left IMHV. It is concluded that IMHV
responses do not passively reflect those of hippocampal neurons.
PMID- 9767405
TI - Short communication: long- but not medium-term retention of olfactory memories in
honeybees is impaired by actinomycin D and anisomycin.
AB - Although work in a wide variety of species and paradigms has demonstrated that
long-term memory is sensitive to the blocking of protein synthesis, previous
studies have suggested that the honeybee might represent an exception to this
rule. Retention tested one day after training was not impaired by the inhibition
of translation by cycloheximide. Using blockers of either transcription
(actinomycin D) or translation (anisomycin), we present experiments that
reconcile this unusual finding by testing over longer retention periods.
Honeybees were conditioned to associate an odourant with a sucrose reward.
Typically, this leads to stable retention over days. However, injection of either
drug led to lower retention after 4 days, whereas retention after 2 or sometimes
even 3 days was unaffected. This dissociates two forms of memory: a protein
synthesis-independent, medium-term memory (up to 3 days) and a protein synthesis
dependent, long-term memory lasting for at least 4 days.
PMID- 9767406
TI - Short communication: transforming growth factor-beta mediates the neurotrophic
effect of fibroblast growth factor-2 on midbrain dopaminergic neurons.
AB - Fibroblast growth factor (FGF)-2 is an established neurotrophic factor for
dopaminergic (DAergic) neurons in the ventral midbrain. Its survival and
differentiation-promoting effects on DAergic neurons in vitro and in vivo are
crucially dependent on the presence, numerical expansion and maturation of
astroglial cells. We show now that transforming growth factor (TGF)-beta, an
established trophic factor for DAergic neurons and product of astroglial cells,
mediates the trophic effect of FGF-2 on DAergic neurons cultured from the
embryonic rat midbrain floor. Antibodies to TGF-beta that neutralize the isoforms
-beta1, -beta2 and -beta3 abolish the trophic effect of FGF-2. FGF-2 increases
TGF-beta3 mRNA and amounts of biologically active TGF-beta determined in a mink
lung epithelial cell assay in a time-dependent manner. FGF-2 also induces levels
of active TGF-beta in neonatal rat astrocytes cultured from midbrain, striatum
and cortex. We conclude that TGF-beta is required for mediating the survival
promoting effect of FGF-2 on DAergic and, possibly, cortical and striatal neurons
grown in the presence of glial cells.
PMID- 9767408
TI - Immuno-stimulatory effects of bacterial-derived plasmids depend on the nature of
the antigen in intramuscular DNA inoculations.
AB - The CpG motifs of bacterial-derived plasmids augment antigen-specific immune
responses and steer those responses towards the T helper 1 (Th1) type. In this
study, we have addressed the immuno-stimulatory effect of intramuscular co
administration of CpG motifs containing vector DNA on the modulation of immune
responses to the haemagglutinin (HA) and the nucleoprotein (NP) proteins of
influenza virus. The co-administration of vector DNA with a HA-encoding plasmid
DNA showed a significant enhancement in the total IgG response, the generation of
cytotoxic T lymphocyte (CTL), and the T-cell proliferative response. In the case
of NP-encoding plasmid DNA inoculations, the co-administration of vector DNA
slightly decreased the total IgG response, although the IgG2a/IgG1 ratio and the
CTL responses to NP were significantly increased. These observations suggest that
the immuno-stimulatory effects of bacterial-derived plasmids depend upon the
nature of the co-administered antigen.
PMID- 9767407
TI - Short communication: protection of axotomized retinal ganglion cells by
adenovirally delivered BDNF in vivo.
AB - Following intraorbital transection of the optic nerve (ON) in rats, more than 80%
of the retinal ganglion cell (RGC) population die by apoptosis within 14 days.
Repeated intraocular injection of brain-derived neurotrophic factor (BDNF) has
been efficient in enhancing RGC survival following ON axotomy. The present study
was designed to define a potential survival-promoting effect of adenovirally
administered BDNF on axotomized RGCs. A single injection of an adenoviral vector
expressing the human BDNF gene from a CMV promoter/enhancer (Ad-BDNF) enhanced
RGC survival 14 days after axotomy by 40.3%. Moreover, a combinatory treatment
regimen consisting of intraocular Ad-BDNF administration and systemic application
of the free radical scavenger, N-tert-butyl-(2-sulphophenyl)-nitrone (S-PBN),
enhanced RGC survival by 63.0%. Our data demonstrate that adenoviral delivery of
neurotrophic factors to the vitreous body is a feasible approach for the
prevention of axotomy-induced RGC death. Further, as shown for S-PBN, therapeutic
regimens that combine local virus-mediated gene delivery with systemic
administration of protective compounds, may offer promising strategies for future
treatment also in human neurodegenerative conditions.
PMID- 9767409
TI - Maintenance of granulocyte numbers during acute peritonitis is defective in
galectin-3-null mutant mice.
AB - Galectin-3, also known as the macrophage marker Mac-2, is a member of a family of
structurally related animal lectins that exhibit specificity for beta
galactosides. In order to investigate the role of galectin-3 in acute
inflammation, we have compared the number of leucocytes present in the peritoneal
cavity of wild type and galectin-3 null mutant mice after intraperitoneal (i.p.)
injection of thioglycolate broth. At day 1 after injection, we found no
difference in the recruitment of mononuclear phagocytes and granulocytes to the
peritoneal cavity. However, 4 days after thioglycolate injection, galectin-3
mutant mice exhibited a significantly reduced number of recoverable granulocytes
compared to wild-type animals. As mutant granulocytes did not exhibit an
accelerated rate of apoptosis and their uptake by macrophages appeared to be
unaffected by the mutation, the phenotype described here suggests that galectin-3
participates in an additional level of control during the resolution of acute
inflammation.
PMID- 9767410
TI - Treatment with recombinant granulocyte colony-stimulating factor (Filgrastin)
stimulates neutrophils and tissue macrophages and induces an effective non
specific response against Mycobacterium avium in mice.
AB - A role of neutrophils in the host response against Mycobacterium avium (MAC) has
recently been suggested. To investigate this matter further, we determined the
effect of granulocyte colony-stimulating factor (G-CSF) on the outcome of MAC
infection in mice. C57BL/6bg+/bg- black mice were intravenously infected with 1 x
10(7) MAC and then divided into four experimental groups to receive G-CSF as
follows: (i) 10 micrograms/kg/day; (ii) 50 micrograms/kg/day; (iii) 100
micrograms/kg/day; (iv) placebo control. Mice were killed at 2 and 4 weeks of
treatment to determine the bacterial load of liver and spleen. Treatment with G
CSF at both 10 and 50 micrograms/kg/day doses significantly decreased the number
of viable bacteria in liver and spleen after 2 weeks (approximately 70.5% and
69.0%, respectively), and after 4 weeks (approximately 53% and 52%, respectively,
P < 0.05 compared with placebo control). Treatment with 100 micrograms/kg/day did
not result in decrease of bacterial colony-forming units in the liver and spleen
after 4 weeks. Administration of G-CSF induced interleukin-10 (IL-10) and IL-12
production by splenocytes. To examine if the protective effect of G-CSF was
accompanied by the activation of phagocytic cells, blood neutrophils and splenic
macrophages were purified from mice receiving G-CSF and their ability to kill MAC
was examined ex vivo. Neutrophils and macrophages from G-CSF-treated mice were
able to inhibit the growth of or to kill MAC ex vivo, while phagocytic cells from
untreated control mice had no anti-MAC effect. These results suggest that
activation of neutrophils appears to induce an effective non-specific host
defence against MAC, and further studies should aim for better understanding of
the mechanisms of protection.
PMID- 9767411
TI - Functional immaturity of rat alveolar macrophages during postnatal development.
AB - Alveolar macrophages (AM) are important in the regulation of immune responses in
the lung, through their role as scavenger cells and through the production of
many bioactive factors. Because in early infancy pulmonary infections are a
recurrent problem, we studied the postnatal functional maturation of AM in a rat
model. AM were isolated from rat lungs by bronchoalveolar lavage at several time
intervals after birth and tested for their ability to ingest Escherichia coli in
the presence of surfactant protein A (SP-A). Furthermore, their capacity to
produce nitric oxide (NO) and interleukin-1 beta (IL-1 beta) after in vitro
lipopolysaccharide (LPS) stimulation was analysed, as well as their capacity to
downregulate proliferation of T cells from both mature and neonatal rats. SP-A
mediated phagocytosis of E. coli by AM was reduced in 14-day-old neonatal rats,
as compared with mature rats (P < or = 0.05). Also the IL-1 beta production by
rat AM after LPS stimulation was impaired at 14 days of age, as compared with IL
1 beta production by AM from mature rats (P < or = 0.05). In contrast, the LPS
induced NO production by rat AM as well as the capacity to inhibit T-cell
proliferation were well developed at all ages tested. In conclusion, during
postnatal development the rat AM is functionally immature, with respect to
phagocytosis and secretion of inflammatory mediators. These differences may
underly the enhanced susceptibility to pulmonary infections as found in human
neonates.
PMID- 9767412
TI - Specific antigen targeting to surface IgE and IgG on mouse bone marrow-derived
mast cells enhances efficiency of antigen presentation.
AB - The discovery that bone marrow-derived mast cells can express major
histocompatibility complex class II molecules and act as antigen-presenting cells
prompted us to evaluate this function when antigen is internalized through fluid
phase endocytosis or via specific uptake by using IgG and IgE antibodies. This
study was performed using a specific T-cell hybridoma developed against Lol p 1,
the major allergen of grass pollen Lolium perenne. Expression of Fc gamma R and
Fc epsilon RI by mast cells led us to investigate the influence of IgG- and IgE
targeted antigen on the antigen-presenting function of mast cells.
Internalization of Lol p 1 through different specific IgG monoclonal antibodies
(mAb) resulted in the activation of Lol p 1-specific T-cell hybridoma at
concentrations about 100-fold less than that required for T-cell stimulation by
uncomplexed antigen. IgE-complexed Lol p 1, which facilitates trapping of antigen
by mast cells, induced an accelerated and more efficient antigen-presenting
capacity of mast cells than that obtained with uncomplexed antigen. However,
aggregation of anti-dinitrophenyl (DNP) IgE mAb by the irrelevant antigen DNP
human serum albumin did not substantially increase the capacity of mast cells to
present Lol p 1 to T cells. This suggests that the mere aggregation of Fc epsilon
RI is not sufficient for enhanced antigen presentation mediated by IgE. Tissue
distribution and strategic location of mast cells at the mucosal barriers and
their capacity to process the antigen through efficient fluid-phase pinocytosis
as well as IgG- and IgE-dependent targeting of antigens provide mast cells with a
prominent role in immune surveillance.
PMID- 9767413
TI - Modulation of antigen-specific T-cell activation in vitro by taurine chloramine.
AB - Taurine chloramine (TauCl) is produced during inflammation by reaction of
hypochlorous acid (HOCl) with taurine, the most abundant free amino acid in
neutrophils. We previously reported that TauCl inhibits the generation of
macrophage inflammatory mediators such as nitric oxide, prostaglandin E2 (PGE2),
tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). In this study,
the activity of TauCl in modulating T-cell activation was investigated. Treatment
of T cells with TauCl (0.1-0.3 mM), prior to activation, was found to inhibit
interleukin-2 (IL-2) release in response to both mitogen and antigen stimulation.
Similarly, pretreatment of A-20 antigen presenting cells (APCs), at low cell
numbers, was found to inhibit their ability to process and present ovalbumin
(OVA) to a specific T-cell hybridoma. In contrast, pretreatment of higher numbers
of A-20 cells with TauCl in the presence of OVA enhanced subsequent presentation
of OVA. Finally, OVA modified with TauCl was processed and presented more
efficiently than native OVA. Thus, TauCl is able to modulate induction of a
specific adaptive immune response at several independent points of the overall
antigen-presenting pathway.
PMID- 9767414
TI - Staphylococcal enterotoxin B-induced T-cell anergy is mediated by regulatory T
cells.
AB - Naive T cells mount a vigorous proliferative response to superantigen (SAg)
stimulation in vivo. The proliferative response is followed by a partial deletion
of responder T cells. Part of the deletion process has recently been attributed
to the action of regulatory cytotoxic T cells that recognize major
histocompatibility complex (MHC) class I-associated antigen receptor determinants
on the target cell surface. Responder T cells that survived the SAg response were
found to be incapable of generating a secondary proliferative response to a SAg
challenge. We show here that this 'anergy' is enforced by CD8-positive regulatory
suppressive T cells. These regulatory cells inhibit cell division of preactivated
T cells but not the Sag response of naive T cells. Regulatory T cells are not
generated in the presence of cyclosporin A and, once activated, become
inactivated or deleted when restimulated in the presence of this
immunosuppressive drug.
PMID- 9767415
TI - Lipopolysaccharide-induced production of tumour necrosis factor and interleukin-1
is differentially regulated at the receptor level: the role of CD14-dependent and
CD14-independent pathways.
AB - Cytokine production induced via CD14-dependent and CD14-independent pathways was
investigated in mouse peritoneal macrophages incubated with lipopolysaccharide
(LPS) or lipid A. Different LPS receptors appear to be responsible for production
of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha)
and IL-1 beta. TNF-alpha production is essentially CD14 dependent, both in the
presence or absence of plasma. In the presence of plasma, endotoxin-induced IL-1
production is mediated by CD14-dependent mechanisms, while in its absence both
CD14-dependent and CD14-independent pathways are involved. Lipid A stimulates
cytokine synthesis through both CD14-dependent and CD14-independent mechanisms,
but its action is weaker than that of LPS, indicating that the polysaccharide
moiety may be necessary for proper stimulation of mouse macrophages by endotoxin.
PMID- 9767416
TI - Peroxynitrite-induced thymocyte apoptosis: the role of caspases and poly (ADP
ribose) synthetase (PARS) activation.
AB - The mechanisms by which immature thymocyte apoptosis is induced during negative
selection are poorly defined. Reports demonstrated that cross-linking of T-cell
receptor leads to stromal cell activation, expression of inducible nitric oxide
synthase (iNOS) and, subsequently, to thymocyte apoptosis. Therefore we examined,
whether NO directly or indirectly, through peroxynitrite formation, causes
thymocyte apoptosis. Immuno-histochemical detection of nitrotyrosine revealed in
vivo peroxynitrite formation in the thymi of naive mice. Nitrotyrosine, the
footprint of peroxynitrite, was predominantly found in the corticomedullary
junction and the medulla of naive mice. In the thymi of mice deficient in the
inducible isoform of nitric oxide synthase, considerably less nitrotyrosine was
found. Exposure of thymocytes in vitro to low concentrations (10 microM) of
peroxynitrite led to apoptosis, whereas higher concentrations (50 microM)
resulted in intense cell death with the characteristics of necrosis. We also
investigated the effect of poly (ADP-ribose) synthetase (PARS) inhibition on
thymocyte apoptosis. Using the PARS inhibitor 3-aminobenzamide (3-AB), or
thymocytes from PARS-deficient animals, we established that PARS determines the
fate of thymocyte death. Suppression of cellular ATP levels, and the cellular
necrosis in response to peroxynitrite were prevented by PARS inhibition.
Therefore, in the absence of PARS, cells are diverted towards the pathway of
apoptotic cell death. Similar results were obtained with H2O2 treatment, while
apoptosis induced by non-oxidative stimuli such as dexamethasone or anti-FAS
antibody was unaffected by PARS inhibition. In conclusion, we propose that
peroxynitrite-induced apoptosis may play a role in the process of thymocyte
negative selection. Furthermore, we propose that the physiological role of PARS
cleavage by apopain during apoptosis may serve as an energy-conserving step,
enabling the cell to complete the process of apoptosis.
PMID- 9767417
TI - Immunolocalization of protease-activated receptor-2 in skin: receptor activation
stimulates interleukin-8 secretion by keratinocytes in vitro.
AB - The protease-activated receptor-2 (PAR-2) is a seven transmembrane domain
receptor related to the thrombin receptor, which is activated in vitro by
cleavage by trypsin. Affinity-purified rabbit IgG raised against a peptide
corresponding to the trypsin cleavage site of PAR-2 was used for an
immunohistochemical study of skin. The expression of PAR-2 in epidermis was
striking, with keratinocytes showing abundant intercellular and cytoplasmic
staining. Basal cells showed the strongest staining intensity and the stratum
corneum was negative. Staining with control IgG used at the same concentration
was consistently negative. The functional expression of PAR-2 by the simian virus
transformed human skin keratinocyte cell line SVK14 was demonstrated by Northern
blot analysis, flow cytometric analysis and the measurement of intracellular
calcium. Treatment of SVK14 with trypsin or a receptor agonist peptide (SLIGKV
NH2) caused a dose-dependent increase in the secretion of the chemokine
interleukin-8 (IL-8) in vitro. The effect of the peptide was specific, since
control acetylated peptide was without activity. We conclude that PAR-2 is highly
expressed by epidermal keratinocytes and receptor activation in vitro leads to
increased IL-8 secretion by keratinocytes. These data raise the possibility that
PAR-2 may play a role in epidermal homeostasis and inflammatory conditions.
PMID- 9767418
TI - Lymphocyte surface marker and cytokine expression in peripheral and mucosal lymph
nodes.
AB - Lymphocyte populations, adhesion molecule and cytokine expression were determined
in lymph nodes draining peripheral (popliteal and prescapular) or mucosal
(abomasal and jejunal) tissue sites using flow cytometry analysis, immunostaining
and cytokine-specific reverse-transcription-polymerase chain reaction (RT-PCR).
Similar proportions of lymphocyte subpopulations were present in all lymph nodes
except for immunoglobulin A+ (IgA+) B cells which were only present in
significant numbers in the gastrointestinal lymph nodes. Peripheral lymph nodes
contained a significantly higher number of CD4+ cells expressing L-selectin and
beta 1-integrin than mucosal lymph nodes while the alpha 4-integrin chain was
expressed at similar levels in all lymph nodes. The peripheral node adressin
recognized by the MECA 79 monoclonal antibody (mAb) was mainly expressed on
peripheral lymph node vessels. RT-PCR analysis showed that interleukin (IL)-10
and IL-4 were preferentially induced in the gastrointestinal lymph nodes while IL
2 and interferon-gamma (IFN-gamma) were induced in all lymph nodes after
polyclonal stimulation. These results indicate that there are substantial
differences in the cell populations and microenvironments of lymph nodes draining
mucosal and peripheral tissue sites in adult sheep.
PMID- 9767419
TI - Expression of CD69 activation marker by endometrial granulated lymphocytes
throughout the menstrual cycle and in early pregnancy.
AB - Flow cytometry studies of first-trimester normal human decidua have proposed that
a proportion of endometrial granulated lymphocytes (eGL), the predominant
leucocyte population in early human pregnancy, co-express CD69. The purpose of
this study was to investigate CD69 expression by immunohistochemistry throughout
the menstrual cycle and in first-trimester human decidua and to determine whether
CD69 expression by eGL is an in vivo characteristic or whether the antigen is
acquired in vitro after tissue disaggregation and cell purification. Single
immunoenzymatic and double immunofluorescence labelling of tissue sections,
supplemented with double immunoenzymatic staining of purified eGL and flow
cytometry, indicated that eGL do not co-express CD69 in situ but that they
acquire the molecule in vitro after cell purification and culture.
PMID- 9767420
TI - The effect of renin-angiotensin system inhibitors on pro- and anti-inflammatory
cytokine production.
AB - The balance between pro- and anti-inflammatory cytokines has been implicated in
the pathogenesis of infectious and auto-immune diseases, and its modulation has
been proposed as a potential therapeutic target. The results reported in the
present study show that modulators of the renin-angiotensin system, such as the
angiotensin-converting enzyme (ACE)-inhibitor captopril and the angiotensin II
receptor type I antagonist valsartan, have potent inhibitory effects on the
lipopolysaccharide (LPS)-stimulated production of pro-inflammatory cytokines
tumour necrosis factor (TNF) and interleukin-1 (IL-1) in vitro. The anti
inflammatory cytokine IL-1Ra is increased by captopril, whereas IL-6 production
is decreased by valsartan. These effects are exerted mainly at high
concentrations of the drugs. Administration of one dose of captopril or valsartan
in therapeutic dosages to patients with essential hypertension did not influence
LPS-stimulated production of cytokines by whole blood. In conclusion, despite
inhibitory effects on pro-inflammatory cytokine production in vitro, it is
unlikely that captopril or valsartan could be used in anticytokine therapeutic
strategies in vivo.
PMID- 9767421
TI - Role of mRNA stability in the different patterns of cytokine production by CD4+
cells from young and old mice.
AB - CD4+ cells from young (3 months) and old (19 months) mice were stimulated by
plate-bound anti-CD3 monoclonal antibody (mAb) alone or also by soluble anti-CD28
mAb. Supernatants were analysed by enzyme-linked immunosorbent assay (ELISA) to
determine cytokine concentrations. Total RNA was extracted from cells, reverse
transcribed and the cDNA amplified by polymerase chain reaction (PCR) to evaluate
the amount of specific mRNA. The results indicate that anti-CD3 alone is not
sufficient to induce interleukin-2 (IL-2) production in CD4+ cells from both
young and old mice. However, anti-CD28, together with anti-CD3 mAb, induces a
much higher production of IL-2 in CD4+ cells from young as compared with old
mice. Conversely, interferon-gamma (IFN-gamma) production is also induced by anti
CD3 alone and is higher in CD4+ cells from old as compared with young mice. Upon
addition of anti-CD28 mAb, IFN-gamma production increases in both groups, but it
remains much higher in old than in young mice. Also the production of IL-4 and IL
10 is induced by anti-CD3 mAb but it is increased by the addition of anti-CD28
mAb. CD4+ cells from old mice produce more IL-4 and IL-10 as compared with cells
from young mice. The amounts of cytokine specific mRNA in CD4+ cells from young
and old mice parallel the cytokine levels in culture supernatants. Results on the
mRNA turnover indicate that when CD4+ cells are stimulated by anti-CD3 or
costimulated also by anti-CD28 mAb, the IFN-gamma, IL-4 and IL-10 specific mRNAs
are more stable in old than in young mice, suggesting that mRNA stability has a
relevant role in the different patterns of cytokine production.
PMID- 9767422
TI - Synergistic augmentative effect of interleukin-10 and CD27/CD70 interactions on B
cell immunoglobulin synthesis.
AB - Interleukin-10 (IL-10) is a potent cytokine that regulates immunoglobulin
synthesis by B cells. CD27/CD70 interactions by direct cell-to-cell contact are
also needed to produce substantial amounts of immunoglobulin. We have
investigated the effects of IL-10 and CD27/CD70 interactions on the
immunoglobulin synthesis. In the presence of IL-10 stimulation, the production of
IgG, IgM and IgA was increased synergistically by the addition of CD27 ligand
(CD70)-transfectants in a dose-dependent manner, which was completely blocked by
anti-CD70 monoclonal antibody. In contrast, CD70-transfectants additively
enhanced the immunoglobulin production in the presence of IL-2, IL-4, or IL-6.
The synergistic enhancement of the immunoglobulin production by IL-10 and CD70
transfectants was remarkable in highly purified CD27+ B cells, but there was no
immunoglobulin production in CD27- B cells. Furthermore, by the addition of CD70
transfectants, the synthesis of IgG1, IgG2, IgG3 and IgG4 was also enhanced in
the presence of IL-10. On the other hand, IL-10 diminished CD27 expression in B
cells. B-cell proliferation was augmented by CD70-transfectants with IL-10 or IL
10 plus IL-2. The addition of IL-2 further augmented the immunoglobulin
production which was synergistically enhanced by IL-10 and CD27 triggering. Taken
together, the co-operative response to IL-10 and CD27/CD70 interactions regulates
B-cell immunoglobulin production.
PMID- 9767423
TI - Lymphotoxin-alpha is an important autocrine factor for CD40 + interleukin-4
mediated B-cell activation in normal and atopic donors.
AB - Stimulation of human B cells with anti-CD40 + interleukin-4 (IL-4) results not
only in proliferation and immunoglobulin E (IgE)-production, but also increased
production of the cytokine lymphotoxin-alpha (LT-alpha) (formerly also known as
tumour necrosis factor-beta (TNF-beta)). Here, we studied the role of LT-alpha
(TNF-beta) in B cells following stimulation with anti-CD40 + IL-4 from normal
versus atopic donors. Anti-CD40 + IL-4 stimulation of peripheral blood
mononuclear cells (PBMC) from atopic donors resulted in enhanced production of
soluble LT-alpha (TNF-beta) and increased membrane LT-alpha (TNF-beta) expression
on the B cells compared with normal donors. Functional evaluation of LT-alpha
(TNF-beta) in CD40 + IL-4-stimulated B cells shows that recombinant LT-alpha (TNF
beta) induces proliferation of B cells and enhances CD40 + IL-4-mediated B-cell
proliferation and IgE synthesis in both normal and atopic donors in a dose
dependent manner. These findings were supported by semiquantitative analysis of
epsilon-germline transcripts using reverse transcription-polymerase chain
reaction (RT-PCR) showing increased epsilon-germline transcription in the
presence of LT-alpha. Furthermore, addition of anti-LT-alpha (anti-TNF-beta) to
CD40 + IL-4-stimulated B cells partially inhibited proliferation and IgE
synthesis in a dose-dependent manner indicating a role of endogenous LT-alpha
(TNF-beta) production by B cells during continued CD40 + IL-4 stimulation. These
data suggest that LT-alpha (TNF-beta) plays a potentially significant role during
B-cell proliferation and IgE synthesis. Moreover, LT-alpha (TNF-beta) production
seems to be differentially regulated in B cells from normal and atopic donors.
PMID- 9767424
TI - Increased serum IgG1 levels and reduced numbers of B-1 B cells in DBA/2J mice.
AB - B-cell heterogeneity studies have historically focused upon BALB/c mice and their
derivatives. In contrast, the B cells of DBA/2J mice, a prototype strain for the
study of the endogenous minor lymphocyte stimulatory (Mls) viral superantigen Mls
1a, have not been extensively investigated. DBA/2J B cells, by functioning as Mls
1a antigen-presenting cells, influence their own differentiation and diversity by
inducing the proliferation and differentiation of specific CD4 T-cell subsets. In
this report, the B cells of DBA/2J and BALB/c mice were compared for their
ability to restore B-cell function in severe combined immunodeficient (SCID)
recipients. Although spleen and bone marrow cells from these strains exhibited
similar restoration of serum IgM production, the transfer of DBA/2J B cells into
SCID mice led to greater IgG1 production. The peritoneal cells of DBA/2J mice
consisted of a lower percentage of B-1 B cells and were less capable of restoring
B-cell function after transfer into SCID recipients. These differences are
discussed with respect to the possible role of viral superantigens in influencing
B-lymphocyte diversity.
PMID- 9767425
TI - Human/BALB radiation chimera engrafted with splenocytes from patients with
idiopathic thrombocytopenic purpura produce human platelet antibodies.
AB - We have previously shown that lethally irradiated normal strains of mice,
radioprotected with severe combined immunodeficient (SCID) bone marrow, can be
engrafted with human peripheral blood mononuclear cells (PBMC). The human/mouse
radiation chimera can mount marked humoral and cellular responses to recall
antigens, as well as primary responses. In the present study, we adoptively
transferred splenocytes from patients with chronic immune thrombocytopenic
purpura (ITP) into lethally irradiated BALB/c mice, radioprotected with SCID bone
marrow. High titres of total human immunoglobulin appeared as early as 2 weeks
post-transplant and declined after 6 weeks, while human anti-human platelet
antibodies were detected 2-8 weeks after the transfer of splenocytes. The
immunoglobulin G (IgG) fraction contained antibodies against glycoprotein (GP)
IIb/IIIa (CD41) or GPIb/IX (CD42). The human platelet antibodies showed a low
level of cross-reactivity with mouse platelets, and thrombocytopenia in the
animals was not observed. Splenocytes from individual ITP patients differed in
their capacity to produce either human platelet antibodies or total human
immunoglobulin. Furthermore, antibodies produced in the murine system were not
always identical to the original antibodies present in the serum of the patients.
The study of the serological aspects of autoantibodies against human platelets in
an animal model might be useful for the investigation of potential therapeutics
in ITP.
PMID- 9767426
TI - Antibodies to the costimulatory molecule CD86 interfere with ultraviolet
radiation-induced immune suppression.
AB - Although almost all of the energy contained within the ultraviolet (UV)
wavelengths of solar radiation is absorbed within the epidermis and upper layers
of the dermis, UV irradiation can suppress the immune response to antigens
introduced at distant, non-irradiated body sites. The production of immune
modulatory cytokines, such as interleukin-10 (IL-10), by UV-irradiated
keratinocytes and its effect on T helper type 1 (Th1)/Th2-cell balance are
thought to play a major role in the induction of systemic immune suppression.
Because it is suggested that costimulatory molecules, such as CD80 and CD86,
differentially stimulate Th1 and Th2 cells we wished to investigate the role of
these costimulatory molecules in the activation of immune suppression. We
injected UV-irradiated mice with monoclonal antibodies to CD80 and CD86 and asked
what effect, if any, this would have on UV-induced immune suppression. Anti-CD86,
but not anti-CD80 or control rat IgG, blocked UV-induced immune suppression.
Moreover, monoclonal anti-CD86 blocked the induction of suppressor T cells
normally found in the spleens of the UV-irradiated mice. Monoclonal anti-CD86
also reversed the UV-induced impairment of systemic antigen-presenting cell
function. IL-10 was detectable in the serum of UV-irradiated mice as compared
with normal controls, and injecting UV-irradiated mice with anti-CD86, but not
anti-CD80 or control rat IgG, blocked the secretion of IL-10 into the serum. We
propose that UV exposure favours costimulation by CD86, which enhances the
production of serum IL-10, thus suppressing Th1-cell-mediated immune reactions.
PMID- 9767427
TI - Role of GM1 binding in the mucosal immunogenicity and adjuvant activity of the
Escherichia coli heat-labile enterotoxin and its B subunit.
AB - Escherichia coli (E. coli) heat-labile toxin (LT) is a potent mucosal immunogen
and immunoadjuvant towards co-administered antigens. LT is composed of one copy
of the A subunit, which has ADP-ribosylation activity, and a homopentamer of B
subunits, which has affinity for the toxin receptor, the ganglioside GM1. Both
the ADP-ribosylation activity of LTA and GM1 binding of LTB have been proposed to
be involved in immune stimulation. We investigated the roles of these activities
in the immunogenicity of recombinant LT or LTB upon intranasal immunization of
mice using LT/LTB mutants, lacking either ADP-ribosylation activity, GM1-binding
affinity, or both. Likewise, the adjuvant properties of these LT/LTB variants
towards influenza virus subunit antigen were investigated. With respect to the
immunogenicity of LT and LTB, we found that GM1-binding activity is essential for
effective induction of anti-LTB antibodies. On the other hand, an LT mutant
lacking ADP-ribosylation activity retained the immunogenic properties of the
native toxin, indicating that ADP ribosylation is not critically involved.
Whereas adjuvanticity of LTB was found to be directly related to GM1-binding
activity, adjuvanticity of LT was found to be independent of GM1-binding
affinity. Moreover, a mutant lacking both GM1-binding and ADP-ribosylation
activity, also retained adjuvanticity. These results demonstrate that neither ADP
ribosylation activity nor GM1 binding are essential for adjuvanticity of LT, and
suggest an ADP-ribosylation-independent adjuvant effect of the A subunit.
PMID- 9767429
TI - Intranasal administration of human immunodeficiency virus type-1 (HIV-1) DNA
vaccine with interleukin-2 expression plasmid enhances cell-mediated immunity
against HIV-1.
AB - DNA vaccine against human immunodeficiency virus type-1 (HIV-1) can induce
substantial levels of HIV-1-specific humoral and cell-mediated immunity. To
develop more potent HIV-1 DNA vaccine formulations, we used a murine model to
explore the immunomodulatory effects of an interleukin-2 (IL-2) expression
plasmid on an HIV-1 DNA vaccine following intranasal administration of the
combination. When the vaccine and expression plasmid were incorporated into
cationic liposomes and administered to mice, the HIV-1-specific delayed-type
hypersensitivity response and cytotoxic T lymphocyte activity were significantly
increased. Restimulated immune lymphoid cells showed enhanced production of both
IL-2 and interferon-gamma and reduced secretion of IL-4. The level of total
antibody to HIV-1 antigen was not greatly changed by coadministration of the DNA
vaccine and IL-2 expression plasmid. An analysis of serum HIV-1-specific IgG
subclasses showed a significant drop in the IgG1/IgG2a ratio in the group that
received the plasmid-vaccine combination. These results demonstrate that the IL-2
expression plasmid strongly enhances the HIV-1-specific immune response via
activation of T helper type-1 cells.
PMID- 9767430
TI - Human and murine T-cell responses to allelic forms of a malaria circumsporozoite
protein epitope support a polyvalent vaccine strategy.
AB - Mouse models and a recent vaccine trial have indicated the importance of T-cell
immunity to the circumsporozoite protein (CSP) of malaria sporozoites. One of the
major impediments for the development of a CSP-based vaccine is that human T-cell
epitopes, identified on the CSP, span regions of significant point mutational
polymorphism. Studies with human and mouse T-cell clones have indicated that this
polymorphism affects T-cell cross-reactivity to Th2R and Th3R, the two most
polymorphic and immunodominant epitopes. We extend this observation with
polyclonal human T-cell lines, from 11 donors, raised to known variants of Th2R.
These lines showed limited but variable cross-reactivity with the heterologous
peptides. T cells from B10.A4(R) (I-Ak) mice immunized with each of 18 natural
variants of Th2R indicated a similar, limited, cross-reactivity. I-Ak competition
assays showed that a number of peptides were unable to bind because of a single
polymorphic residue. In both the human and mouse assays, analysis of the
sequences of immunogenic cross-reactive and non-cross-reactive peptides suggested
that the individual polymorphic residues affect the three-dimensional
conformation of the peptide within the major histocompatibility complex (MHC)
groove in an, as yet, unpredictable way. These observations argue that design of
an epitope able to generate broad cross-reactivity is, to date, not possible.
However, despite the limited cross-reactivity of the individual human T-cell
lines, most of the donors had T-cell repertoires capable of recognizing all or
nearly all of the variants tested, which supports a strategy using a multivalent
vaccine.
PMID- 9767428
TI - Dose-dependent mechanisms relate to nasal tolerance induction and protection
against experimental autoimmune encephalomyelitis in Lewis rats.
AB - Nasal administration of soluble antigens is an exciting means of specifically
down-regulating pathogenic T-cell reactivities in autoimmune diseases. The
mechanisms by which nasal administration of soluble antigens suppresses
autoimmunity are poorly understood. To define further the principles of nasal
tolerance induction, we studied the effects of nasal administration of myelin
basic protein (MBP) on experimental autoimmune encephalomyelitis (EAE) in the
Lewis rat. EAE is a CD4+ T-cell-mediated animal model for human multiple
sclerosis. Nasal administration of guinea-pig (gp)-MBP at a dose as low as 30
micrograms/rat can completely prevent gp-MBP-induced EAE, whereas nasal
administration of bovine (b)-MBP is not effective even at a much higher dosage.
Cellular immune responses, as reflected by T-cell proliferation and interferon
gamma (IFN-gamma)-ELISPOT, were suppressed in rats receiving the two different
doses (30 and 600 micrograms/rat) of gp-MBP, but not after administration of b
MBP. Rats tolerized with both doses of gp-MBP had also abrogated MBP-induced IFN
gamma mRNA expression in popliteal and inguinal lymph node mononuclear cells
compared with rats receiving phosphate-buffered saline nasally. However, adoptive
transfer revealed that only spleen mononuclear cells from rats pretreated with a
low dose, but not from those pretreated with a high dose, of gp-MBP transferred
protection to actively induced EAE. Low-dose (30 micrograms/rat) gp-MBP-tolerized
rats also had high numbers of interleukin-4 (IL-4) mRNA-expressing lymph node
cells, while high-dose (600 micrograms/rat) gp-MBP-tolerized rats had low numbers
of IL-4 mRNA-expressing lymph node cells. Our data suggest an exquisite
specificity of nasal tolerance. Dose-dependent mechanisms also relate to nasal
tolerance induction and protection against EAE in the Lewis rat.
PMID- 9767431
TI - Antigen detection in vivo after immunization with different presentation forms of
rabies virus antigen, II. Cellular, but not humoral, systemic immune responses
against rabies virus immune-stimulating complexes are macrophage dependent.
AB - In this paper we describe the effect of depletion of splenic macrophages on the
uptake, and immune response against, different formulations of rabies virus
antigen. Splenic macrophages were removed by intravenous injection with
clodronate liposomes. beta-propiolacton inactivated rabies virus (RV-BPL) and
immune-stimulating complexes (iscom) containing these antigens were given to
macrophage-depleted and control mice. In the absence of phagocytic cells in the
spleen, antigen is still trapped in the red pulp and to a lesser extent in the
peri-arteriolar lymphocyte sheaths (PALS) for both antigen formulations. The
localization pattern in the main area of immune response induction, namely the
follicles, was unaltered after macrophage depletion. Functionally, the depletion
of splenic and liver macrophages had no influence on the induction of specific
antibody responses in both RV-BPL or RV-iscom immunized mice, even though the
latter presentation form was clearly associated with specific localization in the
marginal metallophillic macrophages. In RV-BPL immunized mice, macrophage
depletion had no influence on proliferative T-cell responses. However, macrophage
depleted mice that were immunized with RV-iscom showed a significant decrease in
proliferative T-cell responses. These results confirm existing ideas on the
spleen as a physical filter rather than an induction site for humoral responses
and shed new light on the efficient role of iscoms as antigen-presenting moieties
in relation to their specific in vivo localization patterns and partial
macrophage dependency.
PMID- 9767432
TI - Cross-linking of Fc(gamma)-receptor on monocytes inhibits hepatitis C virus
specific cytotoxic T-lymphocyte induction in vitro.
AB - In hepatitis C virus (HCV) infection, immune complex (IC)-type virus particles
are frequently observed in circulation. The IC leads to cross-linking of Fcgamma
receptors (FcgammaR) on monocytes and exerts immunoinhibitory function. To test
the roles of IC in HCV-specific cytotoxic T lymphocyte (CTL) induction, we
generated HCV CTL from peripheral blood mononuclear cells of chronic hepatitis C
patients with or without HCV-IC- or immunoglobulin G (IgG)-coated culture plates
and compared their lytic activities. HCV-IC or adherent IgG, which induces
FcgammaR cross-linking, significantly reduced CTL activity. Expression of B7-1 on
monocytes decreased on adherent IgG. In addition, tumour necrosis factor-alpha
(TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) production increased
from cells on adherent IgG and their mRNA expression in monocytes was enhanced.
Anti-TNF-alpha antibody during induction on adherent IgG inhibited lysis;
however, anti-TGF-beta completely reversed its inhibitory effect. These results
demonstrated that HCV-IC or adherent IgG impaired HCV-CTL induction in vitro. The
FcgammaR-mediated CTL suppression occurred via decreased expression of monocyte
B7-1 and/or enhanced production of TGF-beta1.
PMID- 9767433
TI - Different roles are played by alpha beta and gamma delta T cells in acquired
immunity to Chlamydia trachomatis pulmonary infection.
AB - Using gene knockout and wild-type C57BL/6 mice, we examined the role of alpha
beta and gamma delta T cells in the resolution of Chlamydia trachomatis mouse
pneumonitis (MoPn) biovar pulmonary infection. The results show that alpha beta T
cell-deficient (alpha-/-) mice, when compared with wild-type control mice, have
dramatically increased mortality rate and greater in vivo growth of MoPn. The
alpha beta T-cell-deficient mice were as susceptible to MoPn infection as T- and
B-lymphocyte-deficient (RAG-1-/-) mice. Moreover, both alpha beta T-cell
deficient and RAG-1 mutant mice failed to mount delayed-type hypersensitivity
(DTH) responses to organism-specific challenge and showed undetectable interferon
gamma (IFN-gamma) production by spleen cells upon in vitro organism-specific
restimulation. In contrast, gamma delta T-cell-deficient mice exhibited intact
DTH responses and their mortality rate and in vivo chlamydial growth were
comparable to those in wild-type controls. More interestingly, gamma delta T-cell
deficient mice showed significantly higher levels of IFN-gamma production than
did wild-type mice. The data indicate that the alpha beta T cell is the major T
cell population for acquired immunity to chlamydial infection and that gamma
delta T cells may play an ancillary role in regulating the magnitude of alpha
beta T-cell responses.
PMID- 9767434
TI - African trypanosome infections in mice that lack the interferon-gamma receptor
gene: nitric oxide-dependent and -independent suppression of T-cell proliferative
responses and the development of anaemia.
AB - Infection of mice with African trypanosomes leads to a severe immunosuppression,
mediated by suppressor macrophages. Using ex vivo macrophage culture and in vivo
cell transfer, it has been shown that nitric oxide (NO) is a potent effector
product of these cells and causes both lymphocyte unresponsiveness and
dyserythropoiesis. We explored the role of NO in vivo during trypanosome
infection using mice with a disrupted interferon-gamma-receptor gene, which were
unable to respond with macrophage activation and NO synthesis. These mice were
less effective at controlling parasitaemia than the wild types, but showed an
improved splenic T-cell responsiveness and reduced anaemia during the early
stages of infection. The data indicate that, in the mouse, NO is a significant
mediator of immunosuppression only in early infection. Beyond day 10 of
infection, NO-independent mechanisms are of primary significance and the control
of parasitaemia and T-cell responsiveness are not directly related.
PMID- 9767435
TI - Endogenous IL-10 regulates IFN-gamma and IL-5 cytokine production and the
granulomatous response in Schistosomiasis mansoni-infected mice.
AB - In murine Schistosomiasis mansoni circumovum, granuloma formation is regulated by
pro- and anti-inflammatory cytokines. Among the latter, interleukin-10 (IL-10)
has been shown to regulate the inflammatory response. In this study we examined
the role of endogenously produced IL-10 in T-helper 1 (Th1)- and Th2-type
cytokine production and granuloma formation. The dynamics of IL-10 production
through the course of the infection were different in granuloma versus splenic
cells. In the former, production peaked during the early developmental stage (6
weeks of infection) of the granuloma and then declined. In splenocytes production
peaked at 12 weeks, before down-modulation of the granuloma response. In the
developing granuloma both macrophages and T cells secreted IL-10. In anti-IL-10
monoclonal antibody (mAb)-supplemented granuloma cell cultures endogenous IL-10
mediated regulation of interferon-gamma (IFN-gamma) was manifest only at 6 weeks;
that of IL-2 continued throughout the infection (6-20 weeks). IL-4 production was
unaffected, but IL-5 production was regulated at the 6 and 8 weeks time point.
Splenocytes showed regulation of IFN-gamma and IL-2 production at the peak of the
granulomatous response (8 weeks). IL-4 production was not regulated, whereas IL-5
production was regulated only at 6 weeks. Repeated injections of anti-IL-10 mAb
given to mice at 6, 12 or 20 weeks of the infection significantly enhanced liver
and lung granuloma growth, tissue eosinophilia, and IFN-gamma, IL-5 production at
the early developmental phase (6 weeks) of the lesions. Thus, in schistosome
infected mice endogenous IL-10 is shown to regulate Th1- and Th2-type cytokine
production and granuloma formation during the early Th0/Th1 phase of the immune
response.
PMID- 9767436
TI - Interferon-gamma-activated primary enterocytes inhibit Toxoplasma gondii
replication: a role for intracellular iron.
AB - Toxoplasma gondii is an obligate intracellular parasite that infects a wide
variety of nucleated cells in its numerous intermediate hosts including man. The
oral route is the natural portal of entry of T. gondii. Ingested organisms are
released from cysts or oocysts within the gastrointestinal tract and initially
invade the intestinal epithelium. We show that T. gondii invades and proliferates
in cultured primary rat enterocytes, obtained with an original procedure.
Activation of the enterocytes with rat recombinant interferon-gamma (IFN-gamma)
inhibits T. gondii replication, the inhibition being dose dependent. Neither
nitrogen and oxygen derivatives nor tryptophan starvation appear to be involved
in the inhibition of parasite replication by IFN-gamma. Experiments using Fe2+
salt, carrier and chelator indicate that intracellular T. gondii replication is
iron dependent, suggesting that IFN-gamma-treated enterocytes inhibit T. gondii
replication by limiting the availability of intracellular iron to the parasite.
Our data show that enterocytes probably play a major role on mucosal surfaces as
a first line of defence against this coccidia, and possibly other pathogens,
through an immune mechanism. The results suggest that limiting the availability
of iron could represent a broad antimicrobial mechanism through which the
activated enterocytes exert control over intracellular pathogens.
PMID- 9767437
TI - ICAM-1 costimulation induces IL-2 but inhibits IL-10 production in superantigen
activated human CD4+ T cells.
AB - We have previously reported that costimulatory pathways including B7-CD28 and
lymphocyte function-associated antigen-3 (LFA-3)-CD2 shape distinct activation
profiles in human CD4+ T cells. We now show that superantigen (SAg), in
combination with intracellular adhesion molecule-1 (ICAM-1) costimulation drives
a proliferative response accompanied by high levels of interleukin-2 (IL-2) and
moderate levels of interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF).
This response profile differs from that observed in B7 or LFA-3 costimulated T
cells because our previous results showed that B7-CD28 costimulation was
accompanied by high levels of IL-2, IFN-gamma and TNF, whereas LFA-3 was a potent
inducer of IFN-gamma and TNF, but had little influence on IL-2 production. The
ICAM-1-induced IL-2 production could efficiently be abrogated with monoclonal
antibody (mAb) against ICAM-1 or LFA-1, showing that the activation is dependent
of a functional ICAM-1-LFA-1 pathway. SAg-induced IL-2, IFN-gamma and TNF were
detected in both CD4+ and CD8+ T cells, whereas production of IL-10 was
restricted to CD4+ T cells. A major finding in the present study was that ICAM-1
costimulation strongly inhibits IL-10 production in CD4+ T cells. Our data
demonstrate that ICAM-1 costimulation is sufficient to induce large amounts of IL
2. The presence of ICAM-1 results in suppression of IL-10 production in T helper
(Th) cells, which may favour the development of Th1 and not Th2 T cells.
PMID- 9767439
TI - Bolus injection of aqueous antigen leads to a high density of T-cell-receptor
ligand in the spleen, transient T-cell activation and anergy induction.
AB - In vivo anergy can be modelled by administration of soluble peptide to T-cell
receptor (TCR) transgenic mice specific for the moth cytochrome c peptide 88-103
(MCCp). Two weeks after initial peptide treatment, T cells were present in normal
numbers but were unresponsive to antigen stimulation in vitro. Only bolus
injections of peptide, either subcutaneous or intravenous, were effective at
inducing tolerance, while slowly released antigen administered via mini-osmotic
pump failed to result in anergy. Examination of T cells soon after bolus peptide
administration revealed that anergy induction was preceded by a transient
hyperactivation of T cells in vivo. Within 2 hr of peptide treatment, interleukin
2 was detectable in the plasma of the transgenic mice. Interestingly, only bolus
injections of peptide led to high levels of T-cell activation, while adjuvant
emulsified and pump-administered peptide resulted in very low stimulation in
vivo. When the dose of bolus-injected peptide used for tolerization was titrated,
the extent of anergy induction directly correlated with the intensity of early T
cell activation. Indirect measurements of TCR-ligand density on the surface of
antigen-presenting cells following peptide administration revealed that aqueous
peptide delivered via bolus injection generated a large number of major
histocompatibility complex-peptide complexes, while pump-delivered and adjuvant
emulsified peptide did not. These data suggest that high levels of TCR ligand are
required for in vivo T-cell hyperactivation and induction of anergy.
PMID- 9767438
TI - A novel immunosuppressant, FTY720, increases the efficiency of a superantigen
induced peripheral T-cell deletion whilst inhibiting negative selection in the
thymus.
AB - A novel immunosuppressant, FTY720, was generated by chemical modification of ISP
I, an immunosuppressive compound purified from culture filtrates of Isaria
sinclairii. FTY720 directly induces apoptotic cell death in lymphocytes, which is
believed to be the mechanism by which this drug exerts its immunosuppressive
effect. We examined the effect of FTY720 treatment on antigen-induced apoptotic
cell death in peripheral T cells and thymocytes. A superantigen, staphylococcus
enterotoxin B (SEB), induces T-cell antigen receptor (TCR) Vbeta-specific
apoptotic cell death in mature T cells in vivo. In this well-documented
experimental system, FTY720 administration significantly enhanced the efficiency
of superantigen-induced T-cell deletion. We also determined that apoptotic cell
death with DNA fragmentation induced in T-hybridoma cells after stimulation in
vitro with anti-TCR antibodies was enhanced in the presence of non-cytolytic
doses of FTY720. In sharp contrast, negative selection of T cells in the thymus,
another example of antigen-induced apoptosis, was found to be inhibited by FTY720
treatment. A rescue effect was observed on clonal deletion in the H-Y-specific
TCRalpha beta transgenic male thymus. In a chicken egg albumin (OVA)-specific
TCRalphabeta transgenic system, OVA-induced apoptotic cell death of CD4+CD8+
thymocytes was also inhibited by FTY720 injection. Thus, FTY720 increased the
susceptibility of mature T cells to TCR-mediated apoptosis but decreased that of
immature thymocytes. The results in this report suggest that the potent
immunosuppressive effect of FTY720 is, in part, a result of the augmentation of
effects on antigen-induced apoptosis in mature T cells, and that two distinct
apoptotic cell death pathways are operating in mature and immature T cells.
PMID- 9767440
TI - Characterization of E-selectin-binding epitopes expressed by skin-homing T cells.
AB - The glycoprotein counter-receptors for E-selectin borne on skin-homing T cells
are poorly defined. In this study we have used flow cytometry to investigate the
surface expression of potential carbohydrate ligands for E-selectin on HUT78, a
skin-homing cutaneous T-cell lymphoma. These cells possessed high surface
expression of the KM-93 epitope but not HECA 452 or CSLEX1 epitopes. The KM-93
antibody also blocked the binding of HUT78 cells to E-selectin. All these
antibodies are reported to recognize sialyl Lewis X (sLex)-like molecules. Using
an E-selectin affinity matrix, the main glycoprotein isolated from HUT78 cells
was a molecular species of 90 000 MW. Other minor species of molecular weights 40
000, 60 000, 100 000, 120 000 and 200 000 were also identified as potential
counter-receptors for E-selectin. Four of the purified counter-receptors (90 000,
100 000, 120 000 and 200 000 MW) stained positive with the KM-93 antibody.
Immunoblot analysis of these purified glycoproteins established the identity of
the 90 000 MW glycoprotein as l-selectin. Furthermore, an anti-l-selectin
antibody inhibited the binding of HUT78 cells to E-selectin, probably by steric
inhibition of the carbohydrate ligand for E-selectin that is borne on the C-type
lectin domain of l-selectin. These results suggest that a carbohydrate epitope on
l-selectin may act as a ligand for E-selectin on skin-homing T cells.
PMID- 9767442
TI - Autoreactive CD4- CD8- alpha beta T cells to vaccinate adjuvant arthritis.
AB - Studies suggested that experimental autoimmune diseases can effectively be
prevented and treated by application of normal autoreactive T cells or
autoreactive T cells in an attenuated form. In this study, several autoreactive
CD4- CD8- T-cell clones (A2, A6, and A13 cells) were isolated for the first time
from the draining lymph nodes of Lewis rats with adjuvant arthritis (AA).
Surprisingly, intraperitoneal inoculation with A13 cells, but not A2 or A6 cells
protected rats from AA both clinically and histologically. It was demonstrated
that A13 cells were CD4- CD8- alpha beta T cells, and showed proliferative
responses to irradiated syngeneic spleen cells (antigen-presenting cells; APC).
Interestingly, A13 cells proliferated against concanavalin A (Con A) and
staphylococcal enterotoxin B (SEB), but did not show any proliferation to
Mycobacterium tuberculosis (Mt), or its 65 000 MW heat-shock protein (HSP). Rats
protected from AA by inoculation with A13 cells showed a specific anti-idiotypic
delayed-type hypersensitivity reaction compared with other autoreactive T cells
(A2 or A6 cells). These findings demonstrate that AA can be suppressed by
autoreactive CD4- CD8- alpha beta T cells, and these cells may be used as
therapeutic agents in experimental autoimmunity.
PMID- 9767441
TI - A comparison of two techniques for the molecular tracking of specific T-cell
responses; CD4+ human T-cell clones persist in a stable hierarchy but at a lower
frequency than clones in the CD8+ population.
AB - Oligoclonal or clonal T-cell expansions, presumed to be antigen driven, are
frequently sought and followed for diagnostic and prognostic purposes, as well as
to understand more about their natural history. Techniques based on conservation
of T-cell receptor CDR3 length are increasingly widely used, often without
assessment of sensitivity or specificity. We present a comparative evaluation of
a novel modified heteroduplex technique and a CDR3-length-based assay. Dilution
of a known clone in a mixed T-cell population shows that in our hands the
heteroduplex technique is at least 10-fold more sensitive than the CDR3-length
based assay. However, even with this level of sensitivity, we do not detect
clonal expansions in unstimulated CD4+ T cells. This contrasts with the frequent
detection of CD8+ clones in fresh samples and suggests different mechanisms of
clonal homeostasis in the two subsets. We show that both techniques detect
functional expansions after in vitro stimulation with a recall antigen. The
distinct molecular footprint seen with the heteroduplex technique allows
reproducible follow up of specific clonal expansions. We have exploited this to
demonstrate that the repertoire of clones expanded by in vitro tetanus toxoid
stimulation shows stability within an individual, implying long-term maintenance
of multiple CD4+ clones.
PMID- 9767443
TI - Immunodeficiency associated with anorexia nervosa is secondary and improves after
refeeding.
AB - Several studies have addressed the question of starvation effects on immune
function by means of changes in lymphocyte subsets, cytokine induction or
lymphocyte activation. Anorexia nervosa (AN) patients are severely malnourished
and contradictory results have been obtained regarding the accompanying
immunodeficiency, including its assignation as a part of the primary nervous
disorder. In the present work, an extensive immunological function examination
was carried out on 40 AN patients who were compared with a control group of 14
healthy girls. The AN patients were also classified according to their
nutritional status (by the Body Mass Index: BMI), this being critical for a
better understanding of these secondary immunodeficiency bases. Moreover, another
immune system study was performed on five patients after refeeding. Lymphocyte
subsets and function, cytokine induction and peripheral blood concentrations, and
innate as well as humoral immunity were evaluated. Deregulation in the cytokine
network, owing to the interaction of the central nervous (CNS) and immune
systems, seems to be the initial immune alteration in AN immunodeficiency but it
has not been disproved that the immunodeficiency is a direct consequence of the
original psychiatric perturbation. Spontaneous high levels of circulating
interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) have
been observed; this is probably one of the causes of the anomalies found in the T
cell subpopulations (mainly the naive CD4+CD45RA+ reduction and the cytotoxic
CD8+ increase) and T-cell activation status (mainly the down-regulation of the
CD2 and CD69 activation pathways). This finally leads to an impairment, not only
in T-cell function but also in T-cell to B-cell co-operation. The AN specificity
of these results is confirmed by the fact that these immune alterations improve
after refeeding and when nutritional status becomes less critical, which also
suggests that AN immunodeficiency is indeed secondary to malnutrition.
PMID- 9767444
TI - From sentinel to messenger: an extended phenotypic analysis of the monocyte to
dendritic cell transition.
AB - The transitional stages in the relationship between sentinel monocytes and
messenger dendritic cells that are active in adaptive immunity, are, as yet,
unclear. To explore these events, 2-hr adherent peripheral blood mononuclear
cells were used either as monocytes, or cultured for 7 days with granulocyte
macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) to
generate dendritic cells, and the phenotypic features and relationship of the two
cell populations was investigated using an extensive panel of monoclonal
antibodies (mAbs). The features of the shift from monocyte to dendritic cell were
also examined by daily phenotyping during the 7-day culture period. Twenty-five
mAbs, most of which recognized known CD molecules, bound both monocytes and
dendritic cells equally, whereas 19 mAbs exhibited differential staining. Four
molecules not previously reported on dendritic cells were documented: CD87, CD98,
CD147 and CD148. Seven cell-surface molecules (HLA-DQ, CD1a, CD13, CD30, CD43,
CD63 and CD86) were expressed either at very low levels or not at all on
monocytes, but had a strikingly increased expression on dendritic cells,
suggesting a role in antigen presentation. The kinetics of monocyte to dendritic
cell transition revealed a rapid activation phase within the first 24 hr, with a
considerable increase in expression of the activation markers HLA-DR, CD13, CD14
and CD98; this was followed by a down-regulation of CD14 and a more gradual
development of the other dendritic cell features over the remaining 6 days, with
steady increases in CD1a, CD18, CD43, CD86, HLA-DR and HLA-DQ. Thus, these
studies have demonstrated four novel components of the dendritic cell, and have
documented the dynamic multistep nature of the process whereby an antigen
presenting dendritic cell phenotype may emerge from a monocyte precursor.
PMID- 9767445
TI - The regulation of superoxide generation and nitric oxide synthesis by C-reactive
protein.
AB - Activated macrophages utilize both reactive oxygen intermediates and reactive
oxynitrogen intermediates for defence against microbes. However, simultaneous
generation of superoxide (O- 2;) and nitric oxide (NO) could be harmful to host
cells due to the production of peroxynitrite, nitrogen dioxide and hydroxyl
radicals. Therefore, the regulation of the production of these molecules is
critical to host survival. During periods of inflammation or infection, the level
of serum C-reactive protein (CRP) increases in many species. Human and rat CRP
have been shown to bind and interact with phagocytic cells. Since many of the
interactions of CRP involve the binding to the phosphocholine ligand, we studied
the role of CRP in O- 2; and NO generation through the modulation of
phosphatidylcholine (PC) metabolism in macrophages. This study has shown that,
while rat CRP inhibited phorbol myristate acetate- (PMA) induced release of O- 2;
by rat macrophages, CRP-treated macrophages released NO in a time- and dose
dependent manner. CRP increased inducible nitric oxide synthase (iNOS) enzyme as
well as iNOS mRNA levels in rat macrophages. Tricyclodecan-9-yl-xanthogenate
(D609), an inhibitor to PC phospholipase C (PC-PLC), suppressed iNOS induction
but enhanced PMA-induced release of O- 2;. These data indicate that an increased
level of CRP during periods of inflammation may result in differential regulation
of macrophage NADPH oxidase and iNOS activity. Increased hepatic synthesis of CRP
may contribute to the mechanism by which phagocytic cells avoid simultaneous O-
2; and NO synthesis, and this could possibly be mediated through the regulation
of PC-PLC.
PMID- 9767446
TI - Fas ligand (FasL, CD95L, APO-1L) expression in murine mast cells.
AB - Fas ligand (FasL, CD95L, Apo-1L), a type II membrane protein belonging to the
tumour necrosis factor family, induces apoptosis in Fas-bearing cells. As murine
mast cells have been shown to express Fas antigen, we hypothesized that mast
cells might also express FasL. To explore this possibility, we first demonstrated
FasL mRNA in mast cells by reverse transcription-polymerase chain reaction and
FasL protein by immunoblot analysis. FasL protein was shown to be exclusively
located within the cell by flow cytometry. In agreement with this observation,
bone marrow cultured mast cells were unable to kill Jurkat T cells. Our results
demonstrate that FasL is expressed in murine mast cells and suggest that this
murine mast cell FasL is not lytic, owing to the intracellular localization.
PMID- 9767447
TI - Involvement of protein kinase C-delta in CD28-triggered cytotoxicity mediated by
a human leukaemic cell line YT.
AB - Ligation of CD28 molecules expressed on the surface of human leukaemic natural
killer-like YT cells triggers intracellular signals leading to cytolysis of
target cells expressing CD80 or CD86 molecules. Known intracellular events
include tyrosine phosphorylation, activation of phosphatidylinositol 3-kinase,
and protein kinase C (PKC). In this study, we report that PKC-delta isoenzyme
activity is required for CD28-triggered cytotoxicity mediated by YT cells and we
also demonstrate that one of the primary targets of bryostatin 1, a modulator of
PKC activity, is PKC-delta. Treatment of YT cells with bryostatin 1 caused
degradation of PKC-delta, but not other PKC isoenzymes, and completely blocked
the cytolytic activity of YT cells. In addition, PKC-delta-specific antibody
introduced into YT cells by electroporation inhibited partially the YT cell
mediated cytotoxicity of B-lymphoblastoid cell line JY. This effect was specific,
since addition of anti-PKC-delta antibody-blocking peptide in combination with
anti-PKC-delta antibody to YT cells for electroporation, neutralized the effect
of this antibody. These results demonstrate that YT cell cytolytic activity is
dependent on PKC-delta, which is selectively down-regulated by bryostatin 1.
PMID- 9767448
TI - Localization in situ of costimulatory molecules and cytokines in B-cell non
Hodgkin's lymphoma.
AB - Costimulatory molecules are essential in cognate interactions between T and B
lymphocytes. To study the prerequisites of functional interactions between
malignant B cells and intermingled T cells in B-cell non-Hodgkin's lymphomas (B
NHL), we examined the expression of CD40, CD80 and CD86 and their ligands CD40
ligand (CD40L, CD154), CD28 and CTLA4 (CD152) using immunohistochemistry and
confocal laser scanning microscopy. Almost all mucosa-associated lymphoid tissue
(MALT) NHL were positive for CD40 and CD80 and in nine out of 14 cases were
positive for CD86. The majority of follicle centre cell lymphomas (FCCL)
expressed CD40, but were heterogeneous in their expression of CD80 and CD86. Most
diffuse large cell lymphomas (DLCL) were CD80+, but lacked expression of CD86.
These patterns reflect the differences in phenotype of normal marginal-zone B
cells (as counterparts of MALT NHL) and germinal centre cells (as counterparts of
FCCL and DLCL). Counter-receptors on T cells were detectable in 13 of 14 MALT
NHL, 12 of 16 FCCL but only occasionally in DLCL (three of 12 cases). A subgroup
of FCCL was identified with T-cell expression of CD40L, CD28 and CTLA4
simultaneously with strong expression of CD40 and CD86 on the tumour B cells.
These results indicate that MALT NHL and a subset of FCCL are most optimally
equipped for functional interactions with T cells. This may be supported by the
demonstration of cytokine production - mainly in T cells - in MALT NHL
[interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-10] and FCCL (IL-2, IFN
gamma) and to a lesser extent in DLCL.
PMID- 9767449
TI - Serum levels, ontogeny and heritability of chicken mannan-binding lectin (MBL).
AB - Mannan-binding lectin (MBL) is a serum lectin found in mammals and recently also
in birds. It is thought to play an important role in the innate immune defence
through binding to surface carbohydrates on micro-organisms followed by
complement activation via the MBL pathway. This results in opsonization or direct
complement-mediated killing. To gain further knowledge about the physiology and
function of the protein, we developed an enzyme-linked immunosorbent assay for
chicken MBL and used this to investigate the level of MBL in different chicken
strains during embryogenesis, early and adult life. The MBL concentrations in 308
chickens, representing 14 different strains, showed a non-Gaussian, unimodal
distribution profile with a mean concentration of 5.8 micrograms/ml (range 0.4
37.8 micrograms/ml). No difference between the strains could be demonstrated and
no chickens were found deficient in MBL. Ontogenetic studies showed that MBL is
already detectable in embryos at a gestational age of 10 days (11 days before
hatching). At hatching, the level is comparable to the level found in adult
chickens. This level is fairly stable during the first weeks of life, but a
deficiency state develops at 4 weeks of age, whereafter the level is normalized
again at 5 weeks of age. Chickens with relatively low or high MBL levels were
bred with cockerels having similar MBL levels and this resulted in F1 generations
with significantly different MBL levels, suggesting that the protein level is
genetically influenced.
PMID- 9767450
TI - Disease-protected major histocompatibility complex Ea-transgenic non-obese
diabetic (NOD) mice show interleukin-4 production not seen in susceptible Ea
transgenic and non-transgenic NOD mice.
AB - The non-obese diabetic (NOD) mouse is an animal model for insulin-dependent
diabetes that has many similarities to the human disease. NOD mice transgenic for
the Ea gene, allowing expression of the E molecule, are protected from diabetes
and rarely develop insulitis. An Ea transgene mutated in the promoter region,
(DeltaY) lacks E expression on most B cells, thymic medullary epithelium and
primary antigen-presenting cells, and confers no protection whatsoever. We have
used these transgenic NOD mice, together with non-transgenic NOD mice, to study
the correlation of E expression and production of interleukin-4 (IL-4) and
interferon-gamma (IFN-gamma). We show that protected E-transgenic NOD mice have
elevated levels of IL-4 compared with non-transgenic mice, both in the thymus and
in the periphery. However, susceptible DeltaY-transgenic mice have elevated
thymic IL-4 levels, but express almost as little IL-4 as non-transgenic NOD mice
in the periphery. This drop in peripheral IL-4 production seen in DeltaY
transgenic mice thus correlates with the decreased E expression in the periphery
of DeltaY-transgenic NOD mice. In contrast, there were no differences in IFN
gamma production between the three NOD lines. We suggest that Ea-transgenic NOD
mice have E-selected regulatory T cells producing IL-4, which are subsequently
activated by E-expressing primary antigen-presenting cells in the periphery. This
activation would then be instrumental for the E-mediated protection from disease
in NOD mice. Such a process would explain the total absence of protection in
DeltaY-transgenic NOD mice, despite their widespread E expression.
PMID- 9767451
TI - Characterization and specificity of B-cell responses in lupus induced by
Mycobacterium bovis in NOD/Lt mice.
AB - A single dose of pasteurized Mycobacterium bovis administered intravenously to
prediabetic non-obese diabetic (NOD) mice prevented the onset of type 1 diabetes
but precipitated a systemic 'autoimmune rheumatic disease' (ARD) similar to
systemic lupus erythematosus. This syndrome was characterized by haemolytic
anaemia, anti-dsDNA and anti-Smith antigen (Sm) antinuclear autoantibodies,
increased severity of sialadenitis and glomerular immune complex deposition.
Here, we examine the specificity of the autoantibody responses in M. bovis
treated NOD mice. Large amounts of antibody were detected to the
Sm/ribonucleoprotein (RNP) complex, of which the 28 000 MW polypeptide appeared
to be immunodominant. The IgG subclass involved in the anti-Sm response was
primarily IgG2a. Antibodies against dsDNA were also detected, but the subclass of
this response was mixed, with IgG2a and IgG2b being present in equal amounts.
Together, these findings argue against a role for immune deviation towards T
helper type 2 (Th2) responses in pathogenesis of the disease. The anti-dsDNA and
anti-Sm reactivities were not mediated by polyreactive antibodies since neither
antigen could cross-compete plasma antibody binding to the other in competitive
enzyme-linked immunosorbent assay. The role of polyclonal B-cell activation was
examined by measuring total gamma-globulin as well as IgG reactive with other
nuclear antigens including Ro60, Ro52 and La, which although not a major
component of the autoantibody responses in these mice, did show small but
significant increases following immunization with M. bovis. Thus polyclonal
stimulation, while likely to be occurring, was not directly responsible for
production of anti-Sm antibodies.
PMID- 9767452
TI - T-cell receptor Vbeta gene expression in experimental lupus nephritis.
AB - A limited T-cell receptor (TCR) Vbeta repertoire employed by autoreactive T cells
may be related to the development and course of autoimmune diseases. Vbeta
repertoire skewing has been observed not only in man, but also in animal models
of several human autoimmune diseases, such as MRL-lpr mice, which spontaneously
develop a systemic lupus erythematosus (SLE)-like disease. Murine chronic graft
versus-host disease (GVHD) is an inducible model for SLE, involving direct
interaction between donor T cells and recipient B cells. It is not known whether
Vbeta-specific T-cell subsets are pathogenically involved in this model.
Retroviral superantigens such as Mls-1 are known to have a profound impact on the
TCR Vbeta repertoire in mice. Restriction of the peripheral TCR repertoire may
result from intrathymic expression of Mls-1, which causes deletion of T cells
expressing Vbeta6, -7, -8.1, or -9. Mls-1 incompatibility between donor and
recipient can be used to determine the involvement of these TCR Vbeta families in
GVHD. In the present study we induced GVHD in several strain combinations to
investigate TCR Vbeta gene expression during GVHD, and the effect of Mls-1
incompatibility on the TCR Vbeta repertoire. TCR Vbeta gene expression was
determined using an RNase protection assay. Our results indicate that T cells
expressing the Vbeta2 or Vbeta16 chain play an important pathogenetic role, while
T cells bearing the Vbeta1 or Vbeta6 chain may be related to self-limitation of
the lupus-like disease in this model.
PMID- 9767453
TI - Amidolytic and peptidolytic activities of immunoglobulin G present in sera from
patients with rheumatoid arthritis, Sjogren's syndrome and systemic lupus
erythematosus.
AB - Polyclonal immunoglobulin G (IgG) from healthy subjects was found to be capable
of hydrolyzing carbobenzoxy-Val-Gly-Arg-p-nitroanilide (a synthetic chromogenic
substrate for trypsin) and D-Pro-Phe-Arg-p-nitroanilide (a substrate for plasma
kallikrein). Statistically significant elevation of activity against the former
substrate was found in patients with rheumatoid arthritis (RA), but not in
patients with Sjogren's syndrome (SjS) or systemic lupus erythematosus (SLE). On
the other hand, IgG samples from the patients with these three autoimmune
diseases showed reduced activity against d-Pro-Phe-Arg methylcoumarinamide,
although the differences were not statistically significant. Preliminary studies
have shown that two out of three IgG samples from RA patients exhibited the
activity of cleaving a pentapeptide, Gln-Arg-Arg-Ala-Ala, whereas virtually no
cleavage of the same peptide was observed with IgG from healthy controls or from
patients with SjS or SLE.
PMID- 9767454
TI - An anti-inflammatory role for interleukin-11 in established murine collagen
induced arthritis.
AB - Interleukin-11 (IL-11) is a cytokine belonging to the IL-6 family which has both
pro- and anti-inflammatory potential. Like IL-6 it can diminish tumour necrosis
factor-alpha and IL-1 production, and augment immunoglobulin synthesis. We have
explored the immunomodulatory effects of IL-11 treatment in mice in a model of
inflammatory autoimmune joint disease, collagen-induced arthritis (CIA).
Recombinant human IL-11 was administered at various doses to DBA/1 mice after the
onset of CIA. IL-11 treatment caused a significant reduction in the clinical
severity of established CIA, which was associated with protection from joint
damage, as assessed by histology. Although there was a suggestion at high doses
of IL-11 that the anticollagen type II (CII) response may have been augmented,
there was no statistically significant effect of IL-11 treatment on anti-CII
antibody levels. Similarly, the acute-phase reactant serum amyloid P was only
elevated in mice receiving very high doses (50-100 microgram/day) of IL-11.
Endogenous IL-11 was abundantly produced in synovial membrane cultures derived
from CII-immunized mice with active disease, suggesting that, as in rheumatoid
arthritis, this cytokine is spontaneously produced in the inflammatory response
in CIA. The results presented here demonstrate an anti-arthritic immunoregulatory
role for IL-11 in murine CIA, and suggest that IL-11 is a candidate therapeutic
molecule for human inflammatory arthritic diseases.
PMID- 9767455
TI - CD4+ T-cell-mediated cytotoxicity against staphylococcal enterotoxin B-pulsed
synovial cells.
AB - Apoptosis of synovial cells in rheumatoid arthritis (RA) synovium determined in
vivo is suggested to counteract the overgrowth of synovium. Immunohistological
examination has revealed the infiltration of activated CD4+ T cells, which
express Fas ligand (FasL), in RA synovium. The presence of a putative antigen
(Ag) of autoimmune disorders in a target organ may induce the activation of
specific T cells in the inflammatory region such as RA synovium. We examined the
possible role of CD4+ T cells activated by synovial cells in a staphylococcal
enterotoxin B (SEB)-dependent manner, inducing synovial cell apoptosis. Synovial
cells were cultured with or without interferon-gamma (IFN-gamma) and further
incubated with CD4+ T cells in the presence of SEB. After the cocultivation, both
the cytotoxicity and FasL expression of CD4+ T cells were investigated.
Constitutive Fas expression was detected on both unstimulated and IFN-gamma
stimulated synovial cells. CD4+ T cells did not kill SEB-pulsed unstimulated
synovial cells efficiently. In contrast, when CD4+ T cells were incubated with
IFN-gamma-stimulated synovial cells with SEB whose human leucocyte antigen (HLA)
DR and -DQ expression was markedly induced, significant cytotoxicity by these
cells against synovial cells was detected. The addition of anti-HLA-DR and -DQ
monoclonal antibodies (mAbs) or human Fas chimeric protein (hFas-Fc) reduced this
cytotoxicity. FasL expression of CD4+ T cells cocultured with IFN-gamma
stimulated synovial cells with SEB was significantly induced. Furthermore, the
addition of mAbs against CD54, CD58 and CD106 inhibited both the cytotoxicity and
FasL expression of CD4+ T cells induced by IFN-gamma-stimulated synovial cells in
the presence of SEB, indicating the importance of costimulatory molecules on
synovial cells in activating CD4+ T cells. Our results suggest that CD4+ T cells
are activated by synovial cells by an SEB-dependent manner and express FasL,
inducing Fas-mediated apoptosis of the latter cells. These phenomena may regulate
the overgrowth of synovial cells in RA synovium.
PMID- 9767456
TI - Splenic B cells are required for tolerogenic antigen presentation in the
induction of anterior chamber-associated immune deviation (ACAID).
AB - Ocular immune privilege is the result of a number of protective mechanisms,
including a specialized immune response to antigen encountered in the anterior
chamber of the eye. Anterior chamber-associated immune deviation, or ACAID, is
characterized by the antigen-specific, selective down-regulation of systemic cell
mediated and humoral immune responses. One current hypothesis of the initiation
of ACAID predicts that ocular APC process antigen and then migrate out of the eye
and to the spleen where various regulatory T-cell populations are generated. A
novel in vitro model of the ACAID spleen was developed to study the cells
involved in the generation of suppressed T-cell immunity. ACAID APC co-cultured
with whole splenocytes or splenic B and T cells induced efferent suppressors of
delayed-type hypersensitivity (DTH). However, ACAID APC co-cultured with splenic
T cells did not generate efferent suppressors of DTH. The requirement for B cells
was confirmed with B-cell knockout mice. ACAID APC co-cultured with splenocytes
from B-cell knockout mice did not induce efferent suppressors of DTH. Moreover,
ACAID could not be induced in B-cell knockout mice in vivo. The reconstitution of
B-cell knockout mice with wild-type B cells restored ACAID. In summary, these
data confirm the role for B cells in the splenic phase of ACAID. A putative
mechanism predicts that ACAID APC release antigenic peptides to B cells in the
spleen. B cells then present antigen in a tolerogenic manner leading to the
generation of regulatory T cells.
PMID- 9767457
TI - Lymphotactin: a key regulator of lymphocyte trafficking during acute graft
rejection.
AB - The attraction of leucocytes to allografts is essential for rejection. The
process is controlled by chemokines. In order to clarify the role of lymphotactin
(a cytokine that represents a novel branch of the chemokine superfamily) in
regulating leucocyte trafficking during graft rejection, we used rat renal
transplantation models to examine its gene expression and the distribution of
lymphotactin-expressing cells in renal grafts. Lymphotactin mRNA was upregulated
strongly in acutely rejecting renal allografts. The mRNA was undetectable in
isografts, chronically rejecting renal allografts or normal kidney. Once
lymphotactin was expressed, large numbers of infiltrating lymphocytes were seen.
Moreover extended studies demonstrated that in cultured rat spleen cells the
expression of lymphotactin mRNA was markedly induced by phytohaemagglutinin (PHA)
or phorbol myristate acetate (PMA), and such induction was inhibited by the
immunosuppressive drugs FK506 and cyclosporin. Collectively, these observations
provide new evidence demonstrating that lymphotactin is a key regulator of
lymphocyte motility and adhesiveness during acute allograft rejection. FK506 and
cyclosporin inhibition of lymphotactin expression is likely to represent an
important molecular mechanism of the action of the drugs.
PMID- 9767459
TI - Analysis of T cells recruited during delayed-type hypersensitivity to purified
protein derivative (PPD) versus challenge with tuberculosis infection.
AB - The delayed-type hypersensitivity (DTH) to purified protein derivative (PPD) test
has been used to infer about protective immunity to Mycobacterium tuberculosis
and to diagnose tuberculosis. We showed that in memory tuberculosis-immune mice
both DTH to PPD and resistance to M. tuberculosis could be effectively elicited
in the footpad and both reactions led to the accumulation of reactive T cells in
the regional lymph nodes with a CD4+ phenotype and characterized by the secretion
of high levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) and no IL
4. By adoptive transfer into nude mice of highly purified CD4+ T cells harvested
during the recall of protective immunity it was confirmed that this population
mediated both manifestations. However, the specificity of the T cells recruited
during these processes were found to differ markedly; T cells involved in
protection to a challenge with live tuberculosis bacilli recognized predominantly
low-mass culture filtrate antigens below 15 000 MW, while cells recruited during
DTH to PPD were directed to molecular mass fractions between 15 000 and 31 000.
Using single purified antigens we showed that the latter cells recognized the
secreted mycobacterial protein Ag85B and the heat-shock proteins, DnaK and GroEL.
Protective T cells, in contrast, were characterized by a very high frequency of T
cells directed to the ESAT-6 peptide 1-20.
PMID- 9767458
TI - Direct and rapid induction of migration in human CD4+ T lymphocytes within three
dimensional collagen matrices mediated by signalling via CD3 and/or CD2.
AB - Specific activation of T cells requires stable cell-cell interaction; however,
little is known how the transition from a previously motile state into a sessile
state following activation is achieved. We investigated the direct effect of T
cell receptor (TCR)/CD3 complex engagement and/or stimulation of the accessory
molecule CD2 on the locomotion of peripheral human T cells within three
dimensional (3-D) collagen lattices. Simultaneous engagement of CD3 and CD2 very
potently stimulated T-cell migration, resulting in the recruitment of previously
sessile cells (about 24% of the total population was additionally recruited) as
well as an increase in the mean duration of active locomotion. This induction of
migration was accompanied by an increased tyrosine phosphorylation of a 125 000
MW substrate corresponding to the focal adhesion kinase. Using confocal laser
scanning microscopy we detected antibody-induced receptor capping into the uropod
of migrating T cells whereas untreated control cells displayed an even
distribution of CD3 and CD2 on the cell surface. Less pronounced induction of
locomotion was achieved following triggering of CD3 or CD2 alone. Thus, in 3-D
collagen lattices specific T-cell activation did not lead to cessation of
cellular migration but rather induced cytoskeletal activity that ultimately
resulted in vigorous locomotory activity.
PMID- 9767460
TI - T cell- and perforin-dependent depletion of B cells in vivo by staphylococcal
enterotoxin A.
AB - Bacterial superantigens bind to major histocompatibility complex (MHC) class II
and subsequently activate both CD4+ and CD8+ T lymphocytes expressing certain T
cell receptor (TCR)-Vbeta chains. In response to superantigen exposure these
subsets proliferate, produce large amounts of proinflammatory cytokines and in
addition CD8+ cytotoxic T lymphocytes (CTL) are induced. Previous studies in
vitro have shown that these CTL effectively lyse MHC class II-expressing cells
presenting the proper superantigen. However, it is unknown whether superantigens
induce a similar response towards MHC class II+ antigen-presenting cells in vivo.
In this study we demonstrate that administration of repeated injections of the
superantigen staphylococcal enterotoxin A (SEA) to TCR-Vbeta3 transgenic mice
results in a loss of MHC class II-expressing cells in the spleen. Analysis of
different MHC class II+ subsets revealed a selective depletion of CD19+ B cells,
while F4/80+ macrophages increased in number. Depletion of T cells with anti-CD4
or anti-CD8 monoclonal antibody indicated that CD8+ T cells were crucial for SEA
induced cytotoxicity in vivo. Repeated injections of SEA to perforin-deficient
mice resulted in significantly less B-cell depletion compared with control mice.
This suggests that superantigen-activated CD8+ T cells lyse MHC class II+ antigen
presenting cells in a perforin-dependent manner in vivo. It is suggested that
this represents a novel bacterial immune escape mechanism, which may particularly
impair local humoral immune responses.
PMID- 9767461
TI - Interleukin-1beta partially alleviates cyclosporin A-induced suppression of IgG1
isotype response to thyroglobulin in BALB/c mice in vivo.
AB - Cyclosporin A (CsA) at 120 mg/kg body weight when injected subcutaneously into
BALB/c mice along with thyroglobulin emulsified in incomplete Freund's adjuvant
(IFA) was found to suppress antigen-specific IgG titre by 86%. Isotyping revealed
that both IgG1 and IgG2a titres were suppressed by 87% and 57%, respectively. But
under identical conditions when complete Freund's adjuvant (CFA) was used, the
suppression of antigen-specific IgG, IgG1 and IgG2a titres was 50%, 51% and 55%,
respectively. Injection of anti-IL-1beta-neutralizing hamster monoclonal
antibodies along with thyroglobulin and CsA emulsified in CFA increased the
suppression of antigen-specific IgG titre. Under such conditions the IgG1 titre
was suppressed more than the IgG2a titre. Recombinant human interleukin-1
receptor antagonist (rhuIL-1ra) also enhanced the suppression caused by CsA in
the presence of CFA but control hamster immunoglobulin had no such effect.
Recombinant human IL-1beta, when administered along with thyroglobulin and CsA
emulsified in IFA, alleviated the suppression of antigen-specific IgG titre and
the IgG1 titre was alleviated more than the IgG2a titre. Under identical
conditions, rhuIL-1ra did not alleviate CsA-induced suppression. Lymphocytes from
the lymph nodes of thyroglobulin-sensitized BALB/c mice when stimulated in vitro
by thyroglobulin in the presence of CsA, secreted very little interferon-gamma
(IFN-gamma) and IL-4, but on addition of an optimal dose of rhuIL-1beta, IFN
gamma and IL-4 secretion was partially restored.
PMID- 9767462
TI - Lack of SC/pIgR-mediated epithelial transport of a human polymeric IgA devoid of
J chain: in vitro and in vivo studies.
AB - Three human polymeric IgA (pIgA) myeloma proteins of tetrameric size were
compared for their J-chain content, their in vitro secretory component (SC)
binding ability, and their capacity to be transcytosed by polymeric
immunoglobulin receptor (pIgR)-expressing epithelial cells in vitro and rat
hepatocytes in vivo. One of the three pIgA preparations, pIgA-L, was shown to
lack J chain and was unable to combine with purified free human and rat SC,
whereas pIgA-G and pIgA-C contained J chain and combined readily with SC.
Furthermore, pIgA-L was not transferred into rat bile after intravenous
injection, and was hardly transported apically by polarized Madin-Darbey canine
kidney cell monolayers expressing the human pIgR, whereas pIgA-G and pIgA-C were
efficiently transported in both test systems. Together with our recent
demonstration that antibodies to human J chain block the SC/pIgR-mediated
epithelial transport of pIgA, these data unanimously confirm the proposed key
role of J chain in the epithelial transport of polymeric immunoglobulins into
exocrine secretions.
PMID- 9767464
TI - Inhibition of sCD23 and immunoglobulin E release from human B cells by a
metalloproteinase inhibitor, GI 129471.
AB - Soluble CD23 (sCD23) has been proposed to play an important role in the up
regulation of immunoglobulin E (IgE) synthesis. Production of sCD23 is dependent
on the proteolytic cleavage of membrane CD23, but the protease(s) involved in
this process remain unknown. Preliminary data, obtained by testing a panel of
protease inhibitors, suggested that this enzyme may be a zinc-dependent
metalloproteinase. Therefore, we investigated the effect of a standard
hydroxamate-type Zn2+ metalloproteinase inhibitor (GI 129471) on both sCD23 and
IgE release from human tonsillar B cells, stimulated with interleukin-4 (IL-4)
and anti-CD40. Incubation of cells for 3 days with GI 129471 inhibited the
production of sCD23 with an IC50 of 602 nm+/-3 nm (n=3), but by 14 days the
activity of the compound against sCD23 had decreased by greater than threefold
(IC50 2+/-0.26 microM; n=3). On the other hand, GI 129471 caused a potent
inhibition of IgE production, with no apparent loss of activity over the culture
period (14 days: IC50 250 nm+/-72 nm; n=3). Time-course studies showed that,
despite loss of activity against sCD23, inhibition of sCD23 production early in
the culture was able to cause a potent and long-lasting inhibitory effect on IgE.
Furthermore, we also showed that the activity of GI 129471 is selective for IgE,
as no effect was seen on immunoglobulin G1 (IgG1) or IgG4 production at test
concentrations as high as 10 microM. These results support the hypothesis that
metalloproteinases may be involved in the proteolytic cleavage of CD23 and
subsequent regulation of IgE synthesis. Inhibition of the protease(s) responsible
for such cleavage may be of value in the treatment of allergic disease.
PMID- 9767463
TI - Eosinophilia, IgE production, and cytokine production by lung T cells in surface
CD4-deficient mutant mice infected with Toxocara canis.
AB - Mutant mice deficient in CD4+ T cells and their normal and heterozygous
littermates were infected with Toxocara canis, and compared for eosinophilia,
total and Toxocara-specific immunoglobulin E (IgE) production, and in vitro
cytokine production by lung cells. The numbers of eosinophils in the peripheral
blood of normal and heterozygous mice peaked on days 10 and 21, although mutant
mice showed eosinophilia with a peak on day 10. This indicates that the first
peak on day 10 is CD4 independent and the second peak is CD4 dependent. Before
infection, the levels of total IgE had no significant difference among the three
groups of mice. Total and Toxocara-specific IgE in all genotypes of mice
increased after infection, and was the highest in normal mice and the lowest in
mutant mice. In vitro production of interleukin (IL)-5 and IL-4 by total lung
cells was the highest in normal mice and the lowest in mutant mice. CD4+ and CD4-
CD8- T lymphocytes, but not CD8+ T lymphocytes produced IL-5 and IL-4 when
incubated with anti-CD3 monoclonal antibody (mAb) and lung-adherent cells. These
results indicated that IL-5 and IL-4 were produced mainly by CD4+ cells and
partly by CD4- CD8- cells, but not by CD8+ cells. In addition, cytokine
production by CD4+ cells was affected by the number of CD4 molecules on their
surface.
PMID- 9767465
TI - Role of mast cells and monoamines in the thrombocytopaenia and mortality elicited
by tumour necrosis factor in mice.
AB - We explored the thrombocytopaenia elicited by the i.v. injection of mouse
recombinant tumour necrosis factor (TNF) in mice. Injection of 10 micrograms of
TNF led to a thrombocytopaenia (evident after 0.5 hr) which was caused by
decreased platelet survival, as seen by the injection of labelled platelets. TNF
induced thrombocytopaenia was not prevented by heparin, nor by depletion of
either fibrinogen or C'. TNF-induced thrombocytopaenia was markedly attenuated in
mice treated with reserpine, an agent that depletes monoamines from mast cells
and other cells, and in the mast-cell-deficient WWv mice. In vitro, TNF elicited
a modest release of monoamine from peritoneal mast cells and from a mast cell
line. When mice are injected with 3H-serotonin (3H-5HT) before TNF, TNF injection
increased the plasma 3H-5HT content 1 hr later, modifications absent in reserpine
pretreated or mast-cell-deficient mice. 3H-5HT content of the small intestine was
markedly depleted in TNF-injected mice, suggesting that this organ is the source
of the plasma 3H-5HT. Drop in body temperature and mortality induced by TNF were
also attenuated in mast-cell-deficient, and in reserpine pretreated mice. These
results indicate that TNF can induce a release of monoamines from mast cells,
mainly from those of the small intestine, a process that contributes to TNF
induced thrombocytopaenia and mortality.
PMID- 9767466
TI - Rat NKR-P1+ CD3+ T cells: selective proliferation in interleukin-2, diverse T
cell-receptor-Vbeta repertoire and polarized interferon-gamma expression.
AB - Cells expressing markers of both natural killer and T lymphocytes (NK T cells) in
humans and mice express a restricted T-cell receptor (TCR) repertoire, are of CD4
CD8- or CD4+ CD8- phenotype, and upon anti-CD3 stimulation secrete large amounts
of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma). NK T cells may be the
primary source of IL-4-promoting T helper type 2 (Th2) responses and/or they
might be involved in regulating the balance between Th1- and Th2-type immune
responses, and may consequently affect susceptibility to autoimmune diseases
associated with a skewed Th phenotype. We show that rat NK T cells selectively
proliferate to IL-2, and use this fact to analyse cytokine production by NK T
cells in two rat strains differentially susceptible to Th1- or Th2-type
autoimmune diseases. Analysis by reverse transcription-polymerase chain reaction
revealed that, in contrast to mouse, rat NK T cells secrete exclusively IFN-gamma
and not IL-4 after anti-CD3 stimulation, and use a wider TCR-Vbeta repertoire,
suggesting that rat NK T cells are not essential for the development of Th2-type
CD4+ T-cell responses.
PMID- 9767467
TI - Modulation of Ly49A receptors on mature cells to changes in major
histocompatibility complex class I molecules.
AB - The expression of murine Ly49 receptors on natural killer (NK) cells and NK1.1+ T
cells is believed to prevent these cells from responding against normal self
tissues. In this report we investigated whether the expression level of Ly49A was
fixed on mature cells or if it could be adapted as the major histocompatibility
complex (MHC) class I environment changed in vivo. By transferring peripheral T
cells from Ly49A transgenic mice into BALB/c nude/nude and B6 nude/nude mice, we
demonstrated that mature cells modulate their Ly49A receptor expression relative
to the in vivo MHC class I environment. These results indicated that the
expression of the inhibitory Ly49A receptor is not permanently fixed during a
maturation and/or education process but rather is adapted to MHC class I changes
on the surrounding cells.
PMID- 9767468
TI - A long-lasting interferon-gamma response is induced to a single inoculation of
antigen-pulsed dendritic cells.
AB - Vaccines against infectious organisms must produce not only long-lasting immunity
but also the appropriate immune response to clear the infection. Obligate
intracellular parasites, such as mycobacteria, require a predominantly cell
mediated immune response rather than antibody. Presentation of antigen by
dendritic cells (DC) has been associated with the development of strong cell
mediated responses generating the production of interferon-gamma (IFN-gamma).
This cytokine has an essential role in the elimination of mycobacteria.
Therefore, we investigated both the duration and the nature of the immune
response after priming with DC pulsed with mycobacterial antigen and compared
this with priming using a conventional adjuvant. We used two strains of mice:
C57BL/6, which inherently produces a T-helper 1 (Th1)-type response to
mycobacterial antigen, and BALB/c, which does not. DC-enriched cell suspensions,
purified DC or cultured bone marrow cells resembling DC (BMAPC) were prepared,
pulsed overnight with PPD and injected intravenously (i.v.) into naive mice. Six
and 12 weeks later, splenic T lymphocytes from these mice were challenged in
vitro with antigen and their proliferative response and cytokine production was
determined. Significant antigen-specific proliferation was observed in all assays
on rechallenge with antigen in vitro 6 and 12 weeks after the initial priming
with DC. IFN-gamma was detected in both strains but was only antigen specific in
the C57BL/6 strain. Purified protein derivative (PPD)-pulsed BMAPC generated
similar responses 6 weeks after priming. Thus, long-term T-lymphocyte responses
and the production of IFN-gamma can be generated using a single inoculation of
PPD-pulsed DC.
PMID- 9767470
TI - NADPH diaphorase-positive dendritic profiles in rat thymus are discrete from
autofluorescent cells, immunoreactive for inducible nitric oxide synthase, and
show strain-specific abundance differences.
AB - Predisposition to autoimmune disorder in Lewis rats has been associated with
abnormal hypothalamic regulation of circulating steroids, leading to inadequate
suppression of T helper 1 (Th1) cell-mediated inflammatory reactions. In
addition, autoimmune syndromes can be triggered within formerly resistant
animals, following damage to the negative selection process of the thymus. A
contribution to the autoimmune-susceptible phenotype may therefore derive from
the status of thymic tolerance. One mechanism of intrathymic negative selection
may involve nitric oxide. Because inducible nitric oxide synthase (iNOS) is known
to be inhibitable by steroids, its expression might be different within strains
having neuroendocrine disturbance. We report on a study to compare intrathymic
iNOS expression in autoimmune-prone Lewis rats with other resistant strains.
Interdigitating cells (IDC), darkly stained for diaphorase, were confirmed as
immunoreactive for iNOS. They were located towards the medullary side of an
accumulation of unstained, but autofluorescent cells (presumed to be macrophages)
that circumscribes the corticomedullary zone. The role of iNOS+ IDC in the
apoptotic deletion of T cells has been suggested by other studies. Despite the
blunted steroidal condition reported for Lewis, nitrergic cell abundance was
shown, by quantitative analysis of histochemical stain, to be on average
approximately twofold lower compared with resistant strains (Fischer and Sprague
Dawley). This trend was evident in males and females, and confirmed by
independent observers. We hypothesize that an intrathymic, iNOS-dependent
mechanism may be important for the suppression of potentially autoreactive T-cell
clones.
PMID- 9767472
TI - Low-cost image-capture system for a scanning electron microscope.
AB - We describe a PC-based active-capture system for recording digital images from a
scanning electron microscope. The system is based on a National Instruments data
acquisition board and a Pentium computer, controlled by software that we have
written in Visual Basic.
PMID- 9767469
TI - Granulocyte-macrophage colony-stimulating factor induces the differentiation of
murine erythroleukaemia cells into dendritic cells.
AB - Dendritic cells (DC) are professional antigen-presenting cells (APC) within the
immune system and antigen-pulsed DC can be used as an effective vaccine for
active immunotherapy of cancer. Granulocyte-macrophage colony-stimulating factor
(GM-CSF) plays an important role in the generation of DC. We previously showed
that GM-CSF can induce murine erythroleukaemia cells (FBL-3) to differentiate
into monocyte-like cells. To develop a new vaccinating method to stimulate the
host immune response to leukaemia, we further investigate whether FBL-3 cells
induced by GM-CSF can differentiate into DC in the present study. After being
treated with GM-CSF, FBL-3 cells expressed high levels of 33D1 and NLDC-145,
which are the specific markers of DC. The expression of MHC-II, B7-1, B7-2 and
vascular cell adhesion molecule-1 (VCAM-1) was up-regulated markedly; the typical
morphology of DC were also observed by electron microscopy. Functionally, the GM
CSF-induced FBL-3 cells could apparently stimulate the proliferation of naive
allogeneic and autologous T lymphocytes and induce the generation of specific CTL
more efficiently than the wild-type FBL-3 cells. Mice immunized with GM-CSF
induced FBL-3 cells could resist the subsequent challenge with the wild-type FBL
3 cells. Collectively, these data indicate that GM-CSF differentiates murine
erythroleukaemia cells into DC phenotypically, morphologically and functionally.
FBL-3-derived DC can be used as a new type of vaccine. Our results may have
important implications for the immunotherapy of leukaemia.
PMID- 9767473
TI - Real-time three-dimensional imaging of macroscopic structures.
AB - We describe an extremely simple method of obtaining optically sectioned images
with conventional low-power imaging systems in real time. A single spatial
frequency grid pattern is projected onto an object. Images taken at three spatial
positions of the grid projection are processed to provide 3D images of
macroscopic structures.
PMID- 9767474
TI - Simultaneous confocal lifetime imaging of multiple fluorophores using the
intensity-modulated multiple-wavelength scanning (IMS) technique.
AB - We demonstrate the simultaneous recording of confocal lifetime images of multiple
fluorophores. The confocal microscope used in the study combines intensity
modulated laser illumination, lock-in detection and spectral separation of the
fluorescent light. A theoretical investigation is presented that describes how
the signal-to-noise ratio (SNR) depends on various factors such as modulation
frequency, degree of modulation and number of detected photons. Theory predicts
that, compared with ordinary intensity images, lifetime images will have a SNR
that is, at best, approximately four times lower. Experimental results are
presented that confirm this prediction.
PMID- 9767471
TI - Rapid recruitment of macrophages in interleukin-12-mediated tumour regression.
AB - In order to study the mechanism of interleukin-12 (IL-12) antitumour activity,
RH7777 rat hepatoma cells were engineered to express mouse IL-12 (mIL-12)
(RH7777/mIL-12) under the tight control of doxycycline (dox). The production of
the mIL-12 protein was regulated by the concentration of dox that was present in
the culture medium. RH7777/mIL-12 cells appeared to have the same tumorigenic
activity as did parental RH7777 cells, when subcutaneously injected into
syngeneic rat (BUF/N) in the absence of dox. However, the tumorigenicity of
RH7777/mIL-12, but not RH7777, cells were significantly decreased when dox was
administrated to the animals. In addition, established tumours of RH7777/mIL-12
cells gradually disappeared upon the induction of mIL-12 by dox. To elucidate the
kinetic profile of immune cells involved in the mIL-12-induced tumour regression,
both histological and immunohistochemical analyses were performed 1, 3 and 14
days after the dox treatment on rats bearing tumours that were approximately 0. 5
cm in diameter. Tumour-infiltrating macrophages began to appear at the tumour
site one day after dox treatment. As time elapsed, the number of tumour
infiltrates including CD4+, CD8+, natural killer (NK) cells and macrophages
gradually increased. In particular, CD8+ and NK cells constituted the major
population of the tumour-infiltrated cells. Furthermore, it was found that
resting peritoneal macrophages (PM) from rats were chemoattracted in response to
mIL-12. The effects of mIL-12 on PM chemotaxis were reproducibly observed in
concentrations as low as 0.1 ng/ml. These findings suggest that IL-12 can
directly recruit macrophages into tumour sites which, in turn, leads to a broad
and intense immunological response against tumour.
PMID- 9767475
TI - Evaluating the performance of fluorescence microscopes.
AB - A simple means of evaluating the performance of fluorescence microscopes is
described. The proposed test gives an overall figure of merit that takes into
account all of the important instrumental parameters that determine image
quality. The essence of the test is to use a specimen whose photobleaching rate
is a measure of the illumination time-intensity integral. When this time
intensity integral is controlled, the signal-to-noise ratio in the image of small
subresolution objects becomes a system-independent measure of light throughput,
resolution and intrinsic noise.
PMID- 9767476
TI - Ultrathin fluorescent layers for monitoring the axial resolution in confocal and
two-photon fluorescence microscopy.
AB - Monomolecular films of polymerized dimethyl-bis[pentacosadiinoic-oxyethyl]
ammonium bromide (EDIPAB) provide one- and two-photon excited fluorescence that
is sufficiently high to quantify the axial resolution of 3-D fluorescence
microscopes. When scanned along the optical axis, the fluorescence of these
layers is bright enough to allow online observation of the axial response of
these microscopes, thus facilitating alignment and fluorescence throughput
control. The layers can be used for directly measuring and monitoring the axial
response of 4Pi-confocal microscopes, as well as for their initial alignment and
phase adjustment. The proposed technique has the potential to supersede the
conventional technique of calculating the derivative of the axial edges of a
thick fluorescent layer. Coverslips with EDIPAB-layers can be used as substrates
for the cultivation of cells.
PMID- 9767477
TI - Dispersion pre-compensation of 15 femtosecond optical pulses for high-numerical
aperture objectives.
AB - The excitation efficiency in two-photon absorption (TPA) microscopy depends
strongly - owing to the square dependence of the TPA fluorescence on the
excitation intensity - on the temporal width of the excitation pulse. Because of
their inherently large frequency bandwidth, ultrashort optical pulses tend to
broaden substantially because of dispersion from propagation through the
dispersive elements in the microscope. In this paper, the dispersion
characteristics of a wide range of microscope objectives are investigated. It is
shown that the induced dispersion can be pre-compensated in all cases for pulses
as short as 15 fs. Because of the excellent agreement between the results from
theoretical modelling and the experimental data, predictions of the possibility
of dispersion control for microscope objectives in general, as well as for even
shorter pulses, can be inferred. Since for TPA imaging the background due to
single photon absorption processes and scattering is independent of the pulse
width, proper dispersion pre-compensation - which minimizes the pulse duration at
the focal point and hence maximizes the excitation efficiency - provides optimal
image contrast in TPA microscopy.
PMID- 9767478
TI - Desktop X-ray microscopy and microtomography.
AB - Recent developments in X-ray microtomography have made it possible to miniaturize
a CT scanner into a versatile and cost-effective desktop system that fits into
any laboratory environment. The possibilities of the technique are demonstrated
for a range of applications. It is also shown how an existing scanning electron
microscope with an X-ray detector can, with a specially developed attachment, be
transformed into an X-ray microscope and microtomograph.
PMID- 9767479
TI - A numerical study of resolution and contrast in soft X-ray contact microscopy.
AB - We consider the case of soft X-ray contact microscopy using a laser-produced
plasma. We model the effects of sample and resist absorption and diffraction as
well as the process of isotropic development of the photoresist. Our results
indicate that the micrograph resolution depends heavily on the exposure and the
sample-to-resist distance. In addition, the contrast of small features depends
crucially on the development procedure to the point where information on such
features may be destroyed by excessive development. These issues must be kept in
mind when interpreting contact microradiographs of high resolution, low contrast
objects such as biological structures.
PMID- 9767480
TI - Measurement-based evaluation of optical pathlength distributions reconstructed
from simulated differential interference contrast images.
AB - Recently a method was presented for reconstructing optical pathlength
distributions (OPDs) from images of weak phase objects obtained by a conventional
differential interference contrast (DIC) microscope. A potential application of
this technique is the determination of the mass of biological objects: by
integrating the optical pathlength over the projected surface of the image of an
object, a measure of the dry mass, i.e. the total mass of all solid constituents
present in the object, is obtained. To assess the possibilities of DIC microscopy
for this application, simulations were performed on computer-generated DIC images
of objects of various sizes, shapes and orientation angles. After reconstructing
the OPDs from these images, the integrated optical pathlength of each of the test
objects was determined, and compared with the expected results. The parameter
settings used in the reconstruction algorithm were found to be very important in
obtaining a reliable measurement. Using optimal parameter settings, errors in the
integrated OPD could be limited to a few per cent for circular objects within the
investigated size range. For non-circular objects, however, the orientation angle
of the object relative to the lateral shift was found to influence the measured
values. Ellipses with their long axes perpendicular to the shift direction had a
significantly higher integrated OPD than ellipses orientated parallel to the
shift. By adjusting the reconstruction parameters the effect could be limited,
but complete elimination of the artefact was not possible within the parameter
range investigated.
PMID- 9767481
TI - Energy-filtered cryotransmission electron microscopy of liposomes prepared from
human stratum corneum lipids.
AB - We used cryo-TEM to examine the morphology of vesicles formed from lipids of the
human stratum corneum (hSC). Human stratum corneum lipid liposomes (hSCLLs) were
prepared in buffer at various pH values, using different preparation methods
(film method, extrusion, ultrasonication, detergent dialysis). The morphology of
hSCLLs at pH 7.4 differed markedly from that of liposomes formed by
phospholipids, showing folds, stacks and membrane thickening. At pH 5.0,
corresponding to natural conditions at the skin surface, membrane structures are
essentially the same as those prepared at pH 7.4. Sharp edges in hSCLLs,
branching membranes and stable membrane stacks were explained by the presence of
ceramides, the major components and structural elements of human stratum corneum
lipids (hSCLs). Thickened areas in the membranes may be caused by the local
accumulation of triacylglycerols and cholesterol esters in the hydrophobic
interior of the bilayer.
PMID- 9767482
TI - Physical and chemical changes in polystyrene during electron irradiation using
EELS in the TEM: contribution of the dielectric function.
AB - We have performed electron energy-loss spectroscopy analysis of polystyrene in
the analytical transmission electron microscope in order to evaluate the
possibility of obtaining both chemical and dielectric information on the polymer
at the submicrometre scale. Irradiation has also been studied, particularly the
influence of the specimen temperature on the kinetics of degradation. The main
results show that polystyrene is resistant to electron beam with a critical dose
of about 104 C m-2 at 127 K. Spectra could be acquired with doses less than this
critical dose. We were thus able to propose an identification of the different
chemical bonds of carbon (including the C-H bond), in agreement with previous X
ray absorption near-edge structure experiments. The chemical changes in
polystyrene due to severe irradiation damage are also visible in the carbon K
edge near-edge structure. At the same time, we calculated the dielectric function
from the low-loss part of the spectra. Interestingly, this part of the spectrum
is the most sensitive to irradiation, since great changes can be seen during
exposure. Lastly, we propose a degradation process, in agreement with all these
results.
PMID- 9767483
TI - Estimation of average particle size from vertical projections.
AB - A new stereological relationship is derived for the estimation of average size
(average width) of a collection of convex particles in a 3D microstructure. The
average size is estimated from measurements performed on projected images of the
microstructure generated by total vertical projections. The stereological
relationship is as follows: D = IC/(2N0beta). D is the average width, ;IC is the
average absolute number of intersections between the specifically oriented and
regularly spaced cycloid shape test lines and particle boundaries observed in the
total vertical projections, N0 is the total number of particles observed in the
total vertical projection and the parameter beta is a characteristic of the
measurement grid; it has units of reciprocal of length. The result is applicable
to any arbitrary collection of convex particles; the particle orientations need
not be isotropic. Only 'intersection counts' are required; it is not necessary to
measure sizes of the particles in the projected images.
PMID- 9767484
TI - Estimating surface area by the isotropic fakir method from thick slices cut in an
arbitrary direction.
AB - The proposed fakir method for estimating surface area is based on counting the
intersections between the surface lying within a thick slice, and an isotropic
spatial grid consisting of a combination of linear probes called fakir probes. An
unbiased procedure using a directly randomized spatial grid rather than sections
with randomized directions is presented. The method is applicable if perfectly
registered serial sections of the surface are available in a thick slice while
the direction of the slice can be arbitrary. The efficiency of the fakir method
using different arrangements of orthogonal triplets of fakir probes is evaluated
and it is shown that mutually shifted probes are superior to non-shifted ones.
The application software for interactive counting of intersections between
computer-generated fakir probes and the surface within the stack of digitized
images is described and demonstrated by two examples: estimation of the surface
area of individual tobacco cell chains using a confocal microscope, and
estimation of the total area of exposed surface of mesophyll cells in a barley
leaf using a wide-field transmission microscope.
PMID- 9767485
TI - Characterization of nanophase Al-oxide/Al powders by electron energy-loss
spectroscopy.
AB - Al nanoparticles were prepared by the inert gas condensation method. After
passivation with oxygen and air exposure we obtained a powdered sample of an Al
oxide/Al nanocomposite material. In the present paper we describe the use of the
electron energy-loss spectroscopy (EELS) technique in a transmission electron
microscope to characterize such nanostructured powders compared with a
microcrystalline commercial aluminium foil. Energy-filtered images showed the
presence of an alumina overlayer of approximately 4 nm covering the aluminium
nanoparticles (23 nm in diameter). EELS analysis enabled us to determine the
total amount of Al2O3 and metallic Al and the structure of the alumina
passivation overlayer in the sample. In particular, the extended energy-loss fine
structure analysis of the data showed a major presence of Al tetrahedrally
coordinated with oxygen in the alumina passivation layer of Al nanoparticles
instead of the octahedral coordination found for a conventional Al foil. This
surprising effect has been attributed to the nanoscopic character of the grains.
The analysis of the electron-loss near-edge structure also determines the
presence of a certain degree of aggregation in this kind of powdered sample as
result of the coalescence of the nanocrystalline grains. The procedure presented
here may have the potential to solve other problems during characterization of
nanostructured materials.
PMID- 9767486
TI - A quantitative method for analysing AFM images of the outer surfaces of human
hair.
AB - Cuticle step height is an important parameter for the quantitative assessment of
human hair. This paper describes a novel, computational method for the rapid
calculation of step heights from atomic force microscope images obtained from
large numbers of specimens. Such an approach is necessary to allow a statistical
analysis of the inherently wide distribution of cuticle step heights
characteristic of a single hair sample. The method described will be of use to
cosmetic formulation chemists and forensic scientists and also to dermatologists
in the field of disease diagnosis.
PMID- 9767487
TI - Neurofilament-L homopolymers are less mechanically stable than native
neurofilaments.
AB - Neurofilaments are cytoskeletal components of neurones that are thought to play
an important structural role in the axon. Specific functions of neurofilaments
are not yet well defined; however, other intermediate filaments are known to have
structural and mechanical functions in different cell types. The atomic force
microscope (AFM) can be used to visualize and manipulate biological structures
through direct physical contact. This allows the AFM to be used to probe the
mechanical properties of these structures. In this paper we present AFM images of
native neurofilaments isolated from bovine spinal cord, composed of NF-L, NF-M
and NF-H, and filaments polymerized in vitro from purified NF-L. Morphologically
these structures, in solution and under ambient conditions, are in agreement with
previous data from electron microscopy. However, repeated scanning of NF-L
homopolymers (in solution) produced significant disruptions of segments of
filaments, both within and at the ends of the filaments. This disruption resulted
in complete loss of portions of the filaments and in breaks in the continuity of
the filaments. Repeated scanning of isolated native neurofilaments under similar
conditions produced no detectable structural changes. Under extremely high
applied forces the native neurofilaments were bent and distorted by the action of
the AFM tip, but were never broken. These data suggest that purified NF-L is not
sufficient to confer complete mechanical stability to neurofilaments.
PMID- 9767488
TI - Global spatial sampling with isotropic virtual planes: estimators of length
density and total length in thick, arbitrarily orientated sections.
AB - Existing design-based direct length estimators require random rotation around at
least one axis of the tissue specimen prior to sectioning to ensure isotropy of
test probes. In some tissue it is, however, difficult or even impossible to
define the region of interest, unless the tissue is sectioned in a specific,
nonrandom orientation. Spatial uniform sampling with isotropic virtual planes
circumvents the use of physically isotropic or vertical sections. The structure
that is contained in a thick physical section is investigated with software
randomized isotropic virtual planes in volume probes in systematically sampled
microscope fields using computer-assisted stereological analysis. A fixed volume
of 3D space in each uniformly sampled field is probed with systematic random,
isotropic virtual planes by a line that moves across the computer screen showing
live video images of the microscope field when the test volume is scanned with a
focal plane. The intersections between the linear structure and the virtual
probes are counted with columns of two dimensional disectors. Global spatial
sampling with sets of isotropic uniform random virtual planes provides a basis
for length density estimates from a set of parallel physical sections of any
orientation preferred by the investigator, i.e. the simplest sampling scheme in
stereology. Additional virtues include optimal conditions for reducing the
estimator variance, the possibility to estimate total length directly using a
fractionator design and the potential to estimate efficiently the distribution of
directions from a set of parallel physical sections with arbitrary orientation.
Other implementations of the basic idea, systematic uniform sampling using probes
that have total 3D x 4pi freedom inside the section, and therefore independent of
the position and the orientation of the physical section, are briefly discussed.
PMID- 9767489
TI - Star length distribution: a volume-based concept for the characterization of
structural anisotropy.
AB - Determination and quantification of anisotropy is of great interest in research
fields dealing with physical structures or surface textures. In this paper, a
volume-based method is presented, which essentially determines the mean object
length in a certain direction for a typical point within a structure or texture.
The mean object lengths for all orientations together form the so-called star
length distribution (SLD). The validity and the accuracy of the SLD method are
investigated, and illustrated by applying it to trabecular bone. By using a line
sampling algorithm, the relation with other anisotropy measures could be studied
analytically. Preliminary tests suggest that with SLD a more exact description of
the mechanical properties of porous structures may be obtained than with other
anisotropy measures. However, due to possible secondary orientations that become
apparent with SLD, a fabric tensor must be of rank higher than two in order to
properly describe an orthogonal structure mathematically.
PMID- 9767490
TI - Assessment of fibre orientation in reinforced concrete using Fourier image
transform.
AB - In this study, ribbon-shaped amorphous cast-iron fibres were used to reinforce a
concrete matrix. X-ray photographs have been taken to detect fibres in situ.
Their orientation has been investigated by automatic image analysis methods.
However, this measurement should not be influenced by the digitization on the
square frame of the analyser. For that purpose, the Fourier transform was used
rather than the rose of direction method. This analysis revealed the transverse
isotropic nature of the spatial arrangement of these fibres, whose axis of
revolution corresponds to the concrete casting axis. Such a morphological
characterization of the fibre-reinforced concrete reveals its mechanical
behaviour.
PMID- 9767491
TI - 3D microscopy of transparent objects using third-harmonic generation.
AB - It is demonstrated that third-harmonic generation (THG) near interfaces in the
refractive index or the third-order nonlinear susceptibility (chi(3)) permits
three-dimensional imaging of transparent objects. The nonlinear dependence of THG
on the excitation power provides inherent optical sectioning. At the same time,
the nonresonant nature of THG, in combination with the near-IR excitation
wavelengths used (1-2 um), render this technique potentially (biologically)
nondamaging and nonbleaching. A specific property of THG imaging is its
sensitivity to - and potential use for imaging of - the relative orientation of
interfaces with respect to the axis of propagation of the excitation radiation.
PMID- 9767492
TI - HREM and STEM of intergranular films at zinc oxide varistor grain boundaries.
AB - Grain boundaries in model ZnO-Bi2O3 and ZnO-Bi2O3-CoO varistors and a commercial
multicomponent varistor have been characterized by high-resolution electron
microscopy (HREM) and scanning transmission electron microscopy (STEM), in order
to determine the relationship between Bi grain boundary segregation and formation
of thin intergranular films. By controlling Bi2O3 content, applied pressure and
temperature, the grain boundary Bi excess has been systematically varied from
nearly zero to GammaBi = 1 x 1015 cm-2 ( approximately 1 monolayer), as measured
by HB 603 STEM using an area-scan method. HREM shows that intergranular amorphous
films are clearly distinguishable in samples with GammaBi > 8 x 1014 cm-2. These
films range in thickness, depending on the Bi excess, from 0.6 to 1.5 nm. Similar
films of approximately 1 nm thickness are widely observed in the commercial
varistor. The composition of the films is a ZnO-Bi2O3 solid solution, which is in
all cases more enriched in ZnO than the bulk eutectic liquid. The Bi-doped grain
boundaries in ZnO varistors therefore contain an intergranular amorphous film
which has not only an equilibrium thickness, but also a distinct equilibrium
composition.
PMID- 9767493
TI - Quantitative analysis of valence electron energy-loss spectra of aluminium
nitride.
AB - The optical properties and electronic structure of aluminium nitride are
determined using valence electron energy-loss spectroscopy in a dedicated
scanning transmission electron microscope. Quantitative analysis of the
experimental valence electron energy-loss spectra to determine the electronic
structure encompasses single scattering deconvolution of the valence electron
energy-loss spectra to calculate the energy-loss function, Kramers-Kronig
analysis of the energy-loss function to reveal the complex dielectric function,
transformation of the dielectric function into the optical interband transition
strength via optical property relations and finally critical-point analysis of
the interband transition strength. The influence of both experimental and
analytical parameters on the final result was studied systematically to define
and improve the understanding of the methods. To check the reliability of this
technique the interband transition strength determined was compared with results
of vacuum ultraviolet spectroscopy. Good agreement was found if sample
preparation was taken into account. The preparation of the specimen for the
transmission electron microscopy has an effect on the electronic structure.
Quantitative analysis of valence electron energy-loss spectroscopy, using the
methods presented, is an important and capable method to determine the electronic
structure of materials and it has the benefit of high spatial resolution.
PMID- 9767494
TI - A simple method for the acquisition of high-quality digital images from analog
scanning electron microscopes.
AB - A method is described for converting video signals of analog scanning electron
microscopes (SEMs) into digital images of high quality. A plug-in card
commercially available for personal computers is used for the on-line
analog/digital conversion. A Windows application program written by the authors,
together with low-level software drivers supplied with the plug-in card, allow
digital images to be recorded, to be displayed simultaneously on the computer
monitor and to be saved as a file in a standardized format. Compared to
conventional photographic images obtained from the SEM camera system, the digital
images possess superior sharpness of outline, excellent image definition,
diminished noise and well-defined grey-scale tones. This method provides SEM
images of high quality for less than $1000 from most older analog SEMs. In
addition, the advantages of digital image processing can be applied to analog
SEMs, including contrast enhancement, digital filtering and multichannel
recording.
PMID- 9767495
TI - Quantitative X-ray microanalysis of solutes in individual plant cells: a
comparison of microdroplet and in situ frozen-hydrated data.
AB - Two different approaches to X-ray microanalysis were tested and compared. These
were the analysis of sap droplets extracted from individual cells (plants grown
and analysed in Bangor, U.K.), and the analysis of cells in situ in frozen tissue
(plants grown and analysed in Hannover, Germany). The data suggest that both
these methods can produce quantitative data accurately reflecting in vivo
concentrations in cereal leaf epidermal cells. The relative merits of the two
procedures are discussed with reference to possible sources of error and their
application to other cell types. Bulk wheat leaf tissue concentrations of K and
Cl did not differ significantly between the two locations, but Ca concentration
was significantly higher in the plants grown in Hannover. Microdroplet analysis
invariably yielded linear responses in the range of concentrations found in plant
tissue (r2 for Ca > 0.97, r2 for K, Cl > 0.99), and interference of other
components of the sap was minimal. The calibration curves for the frozen-hydrated
material were typically linear in the same range of concentrations (r2 for K, Ca,
Cl > 0.95), and the results for K and Cl concentration in these samples were
highly consistent with those measured in the microdroplet experiments. In wheat,
for example, the cellular Cl concentration varied between 12 mM and 119 mM, but
no significant differences were found between the two techniques of measurement.
The results for cellular Ca differed in a manner which might be predicted from
the results of the bulk tissue analyses.
PMID- 9767496
TI - X-ray microanalysis of native airway surface liquid collected by cryotechnique.
AB - The airway surface liquid (ASL) that lines the surface epithelium of the
tracheobronchial tree is of vital importance to the airway defence against
microbial invasion and damage due to environmental factors. Little is known about
the ASL collected in situ in native conditions, owing to difficulties in
collecting ASL without causing damage to the airway mucosa. We have developed a
method to collect and analyse the elemental composition of tracheal ASL in
pathogen-free mice. A specially designed cryoprobe, adapted to the internal
curvature of the mouse trachea, was used to collect the native ASL from the
tracheal surface. The complete ASL elemental composition including [Na] = 5.5 +/-
0.3, [Cl] = 1.3 +/- 0.3, [K] = 1.1 +/- 0.2, [Ca] = 1.2 +/- 0.3, [P] = 1.5 +/-
0.8, [S] = 1.7 +/- 0.4 and [Mg] = 1.3 +/- 0.4 mmol L-1 was determined by X-ray
micro analysis. We demonstrate here that the technique that we used for ASL
collection maintained perfectly the airway epithelial integrity and
functionality.
PMID- 9767497
TI - Cryo-TEM liquid nitrogen splash guard.
AB - A simple aluminium splash guard provides protection for both microscopes and
operators during cryo-transfer procedures.
PMID- 9767498
TI - Intra-abdominal manifestations of Henoch-Schonlein purpura.
AB - Gastrointestinal involvement occurs in approximately two thirds of children with
Henoch-Schonlein Purpura (HSP) and usually is manifested by abdominal pain.
Abdominal symptoms precede the typical purpuric rash of HSP in 14-36%; the
symptoms may mimic an acute surgical abdomen and result in unnecessary
laparotomy. Major complications of abdominal involvement develop in 4.6% (range
1.3-13.6%), of which intussusception is by far the most common. The
intussusceptum is confined to the small bowel in 58%; its frequent
inaccessibility to demonstration by contrast enema means that ultrasonography is
the investigation of choice. Ultrasonography complements serial clinical
assessment, clarifies the nature of the gastrointestinal involvement and reduces
the likelihood of unnecessary surgery. Bowel ischaemia and infarction, intestinal
perforation, fistula formation, late ileal stricture, acute appendicitis, massive
upper gastrointestinal haemorrhage, pancreatitis, hydrops of the gallbladder and
pseudomembranous colitis are seen infrequently. Earlier diagnosis and prompt
treatment of intra-abdominal complications has reduced the mortality from 40% to
almost zero.
PMID- 9767499
TI - The long QT syndrome and seizures in childhood.
AB - Children with the long QT syndrome (LQTS) are prone to life threatening
ventricular arrhythmias. These arrhythmias may result in syncope and seizures
that are often attributed incorrectly to a seizure disorder or to common
fainting. The untreated mortality for symptomatic children with the LQTS is high
but is improved significantly with therapy. Paediatricians should be aware of the
presentations of the syndrome. Recommendations for screening for the syndrome are
given.
PMID- 9767500
TI - Policy statement on breastfeeding. The Australian College of Paediatrics.
PMID- 9767502
TI - Is breast feeding in bed always a safe practice?
AB - OBJECTIVES: To examine whether infants who are being breast fed in their mother's
bed are at increased risk of accidental suffocation. MATERIALS AND METHODS:
Review of all cases of unexpected infant death occurring in South Australia,
Australia during 1996 was undertaken to ascertain whether any cases of sudden
infant death had occurred in association with breast feeding in the parental bed.
All infants had death scene examinations, history reviews and full autopsies
performed. RESULTS: Three of a total of 28 cases of unexpected infant death were
identified where accidental asphyxia associated with breast feeding-related
cosleeping was considered a likely cause of death. Maternal fatigue was a factor
in each of the three cases. There were nine SIDS cases and 16 other cases which
included non-accidental injury, accidental asphyxia, congenital cardiovascular
disease and sepsis. CONCLUSIONS: Accidental asphyxia is a rare but possible
outcome if mothers fall asleep in bed with their infants while breast feeding.
Nursing mothers should be made aware of the potential dangers of fatigue and
sedation in such circumstances. Breast feeding out of bed, or in the company of a
second person who can ensure the safety of the infant if breast feeding is
occurring in bed may prevent these unfortunate fatalities.
PMID- 9767501
TI - Young people with spina bifida: transfer from paediatric to adult health care.
AB - An expectation of health care for young people with disability is that quality
coordinated care continues to be available as they pass from the paediatric to
the adult health care system. While individual clinicians provide this service
well, the widespread absence of coordinated multidisciplinary care for young
people with spina bifida in the adult health care system is a major deficiency.
This paper describes the planning and implementation that underpinned the
transfer of 10 young people with spina bifida from a paediatric to an adult
service. The range of structural, financial and 'cultural' barriers that need to
be overcome before patients can be successfully transferred is highlighted;
lessons learned from this model may serve to facilitate the development of other
transfer services.
PMID- 9767503
TI - Renal tract abnormalities detected in Australian preschool children.
AB - OBJECTIVE: To quantify the incidence of abnormalities in urinalysis and blood
pressure from preschool children and their predictive value in detecting renal
disease within an Australian community. METHODOLOGY: Urine samples, blood
pressure and height measurements and parental reports of significant medical
problems were collected from a total of 9355 South Australian preschool children.
Seven hundred and forty-three children with abnormal results were investigated in
a nephrology outpatient clinic. A control group of 357 children with no
detectable abnormality were also recalled, examined and, where appropriate,
investigated. RESULTS: Nine thousand, three hundred and fifty-five children were
tested. Of these, 0.81% were shown to have a clinically significant renal tract
abnormality. The findings included children with urinary tract infections, vesico
ureteric reflux, glomerular disease, renal calculi, essential hypertension and a
renal neoplasm. While dipstick-based methods were the most specific indicators of
renal tract abnormalities, measurement of blood pressure and urinary beta2
microglobulin were also important in detecting abnormalities. Screening for
glycosuria did not result in the detection of significant undiagnosed
abnormalities. In the control group with no abnormality detected at testing,
there was one case each of aortic coarctation, polycystic kidney disease and
vesico-ureteric reflux diagnosed. CONCLUSION: Undiagnosed renal tract
abnormalities are present in many Australian preschool children. Most are
detectable by a thorough history, examination and urinalysis.
PMID- 9767504
TI - Relative bioavailability and plasma paracetamol profiles of Panadol suppositories
in children.
AB - OBJECTIVE: To determine the relative bioavailability and plasma paracetamol
concentration profiles following administration of a proprietary formulation of
paracetamol suppositories to postoperative children. METHODOLOGY AND RESULTS:
Study A-eight children undergoing minor surgery had blood samples collected
following the rectal administration of either a 250 mg or 500 mg paracetamol
suppository on one day and an equivalent oral dose on the following day. A mean
dose of 13 mg/kg gave a mean Cmax (Tmax) of 7.7 mg/L (1.6 h) and 4.9 mg/L (2.0 h)
following oral and rectal administration, respectively. The mean relative rectal
bioavailability was 78% (95% confidence interval of 55-101%). Study B-20 children
undergoing tonsillectomy and/or adenoidectomy were randomly assigned to receive a
postoperative dose of 500 mg of paracetamol either as 2 x 250 mg liquid filled or
1 x 500 mg hard wax Panadol suppository. A mean dose of 25 mg/kg produced mean
maximum plasma paracetamol concentrations of 13.2 mg/L and 14.5 mg/L at 2.1 and
1.9 h for the hard and liquid filled suppository, respectively. The absorption
rate constants and areas under the curves suggested no difference in the rate or
extent of absorption between the two formulations. CONCLUSION: Absorption of
paracetamol following rectal administration of Panadol suppositories to
postoperative children is slower and reduced as compared to oral therapy. The
hard wax and liquid filled products have similar absorption characteristics. The
usually quoted antipyretic therapeutic range for paracetamol is 10-20 mg/L,
although 5 mg/L may be effective. A single rectal dose of 25 mg/kg will obtain
this lower concentration within 1 h of administration and maintain it for up to 6
h. When given in an appropriate dose for analgesia, maximum plasma paracetamol
concentrations would be available in the immediate postoperative period if the
rectal dose was given 2 h before the planned end of the procedure.
PMID- 9767505
TI - Residential mobility and sudden infant death syndrome.
AB - OBJECTIVE: To examine whether permanent domicile change of the mother, thence the
infant, or temporary relocation of the infant away from his or her usual place of
residence affects the risk of sudden infant death syndrome (SIDS). DESIGN: A case
control nation-wide epidemiological study. SETTING: New Zealand between the years
1987-90. PARTICIPANTS: From the 485 SIDS diagnoses over this time, parents of 393
(81%) SIDS infants consented to participate and these comprise the cases.
Controls were selected by randomly sampling 1800 infants from all babies born
over 78% of the country. Parents of 1592 (88%) control infants participated.
RESULTS: Infants away from their usual address were 1.70 (95% CI: 1.09, 2.66)
times more likely to die from SIDS than infants sleeping at home, after
controlling for likely confounding factors. A partial explanation for this
finding was that SIDS infants were less likely to have been mainly breast fed in
the last two days and were less likely to have shared a room with at least one
adult at the nominated sleep/death. Infants of mothers who shifted house after
their birth, infants having mothers who shifted house within a year prior to the
study interview date, and infants who slept at numerous different houses were
associated with an increased relative risk for SIDS at the univariate level, but
not after adjustment. CONCLUSIONS: Infants are less likely to die in their
accustomed residential environment. This finding needs confirmation by other
studies.
PMID- 9767506
TI - 22q11 deletions in patients with conotruncal heart defects.
AB - OBJECTIVE: To ascertain the frequency of 22q11 deletions in a representative
population of conotruncal heart defects (CTD) and determine which children are at
risk of having a deletion. METHODOLOGY: A clinical and laboratory evaluation of
90 children with CTD, including isolated and syndromic cases. RESULTS: Fifteen
children (17%) were shown to have 22q11 deletions by fluorescence in situ
hybridization (FISH) studies with the Oncor probe N25. Varying degrees of
developmental delay/learning disabilities and facial dysmorphism were common in
these children. None of the isolated cases without dysmorphism had a deletion.
CONCLUSION: 22q11 deletions are a significant cause of a specific form of
congenital heart disease, CTD. It is important to have a high index of suspicion
of the 22q11 deletion disorders in children with CTD and other extracardiac
manifestations so that the diagnosis can be made early and appropriate
interventions implemented.
PMID- 9767507
TI - Effects of blood transfusion on left ventricular output in premature babies.
AB - OBJECTIVE: To investigate the acute effects of red blood cell transfusion on
haemodynamics in preterm babies. SETTING: A neonatal unit in a University
Hospital. PATIENTS: Preterm babies whose postnatal age was less than four weeks
and who required red blood cell transfusion. MEASUREMENT: Cardiac output and left
ventricular systolic function was determined using Doppler echocardiography
before, one hour and 24 h after red blood cell transfusion. Blood pressure and
haematocrit were also recorded at the same time. Mixed-effects regression model
was used to analyse the effect of blood transfusion on left ventricular function
and cardiac output. RESULTS: 57 preterm babies were recruited. Univariate
analysis showed that cardiac index decreased significantly 24 h after transfusion
(P<0.05). Systemic red cell transport increased by an average of 11.1% 24 h after
transfusion (P<0.05). Multivariate analysis showed that the cardiac index was
negatively associated with haematocrit and the index was higher in male babies.
CONCLUSION: There was a significant drop in cardiac index and an increase in
systemic red cell transport 24 h after transfusion in premature babies.
PMID- 9767508
TI - End tidal carbon monoxide concentration in childhood haemolytic disorders.
AB - OBJECTIVES: Endogenous carbon monoxide (CO) is produced mainly by heme
catabolism. As CO is excreted solely by the lung, a simple technique for
measuring the end tidal carbon monoxide (ETCO) level was assessed as a method for
screening for haemolytic disease in children. METHODS: Two end expiratory breath
samples were collected from normal children and from children with haemolytic
disease using a one way valve connector between a mouth piece and an anaesthetic
bag. The samples were analysed by gas chromatography for CO and carbon for
dioxide (CO2). The CO2 value was used to normalise the CO value to an alveolar
concentration. Carboxyhaemoglobin (HbCO) also was measured in the patient group
for correlation analysis with ETCO. RESULTS: A total of 21 children with beta
thalassaemia major, 15 children with other haemolytic diseases (hereditary
spherocytosis n=8, haemoglobin H disease n=3 and thalassaemia intermedia n=4) and
23 normal children were studied. The mean ETCO concentrations in the three groups
were 3.21 p.p.m., 7.41 p.p.m. and 0.69 p.p.m., respectively, which were
significantly different from each other (P<0.0001). There was a significant
correlation between ETCO and HbCO in the patient groups (r=0.85; P<0.0001).
CONCLUSIONS: The end expiratory breath collection device is a simple and feasible
sample collection method. The results confirm that ETCO can be used clinically to
distinguish children with a variety of haemolytic disorders from normal subjects.
PMID- 9767509
TI - Paediatricians: referral rates and speech pathology waiting lists.
AB - OBJECTIVE: This study aimed to examine paediatricians' training in and
understanding of communication development and disabilities and their attitudes
to speech pathology waiting lists and management practices. The relationship
between these factors and referral rates was also investigated. METHODOLOGY: A
total of 229 paediatricians registered with the Australian College of Paediatrics
participated in the study in November 1996. They answered 15 multiple-choice
questions designed to collect demographic information and data pertaining to
their training and understanding of communication development and disabilities.
The survey also obtained data on referral rates to public and private speech
pathology services and on paediatricians' perceptions of speech pathology waiting
lists and possible management strategies. RESULTS: Referral rate to public and
private speech pathology services was found to be associated with the quality of
paediatricians' training in and knowledge of communication development and
disabilities. Paediatricians who had regular contact with speech pathologists
were also more likely to make more referrals. Waiting lists had a negative
influence on referral rate. Treatment rather than assessment waiting lists were
preferred. Paediatricians believed the best solution to speech pathology waiting
lists was an increase in staffing levels particularly in community health
centres. Respondents reported that 1-4 months was an acceptable time to wait for
speech pathology care and indicated the order of importance of factors for
prioritising children. CONCLUSIONS: The results have important implications for
developing best practice models for improving referral processes and access to
speech pathology services for children with communication disabilities.
PMID- 9767510
TI - Predischarge screening of very low birthweight infants by click evoked
otoacoustic emissions.
AB - OBJECTIVE: To evaluate the role of transient evoked otoacoustic emission (TEOAE)
in screening very low birthweight (VLBW) neonatal intensive care unit (NICU)
graduates for hearing loss in comparison with visual reinforcement orientation
audiology (VROA) at 10 months. METHODOLOGY: The study population was all VLBW
neonatal survivors discharged from a single regional NICU at John Hunter
Childrens Hospital (JHCH), Newcastle, New South Wales, Australia, between April
1994 and March 1996. A TEOAE screen was performed prior to discharge and repeated
if necessary until a pass was obtained in at least one ear. Infants were further
screened by VROA at their local Australian Hearing Services (AHS) office at 10
months corrected age. Repeated TEOAE failures were referred directly for an ENT
opinion. RESULTS: A total of 193 infants were eligible for enrolment during the
study period. One hundred and forty-four (75%) received TEOAE testing. The median
age of first screen was 36 weeks gestational age. Ninety-five (66%) of infants
tested passed on a single screen. Of the remaining 49 infants, 26 passed on
retesting (overall pass rate 84%). Twenty-three (16%) were deemed to have failed
the TEOAE screen. Of the 121 infants who passed TEOAE, only 67 (55%) completed
VROA. Two of these infants have a high frequency sensorineural loss and one of
them has been aided. In the 23 who failed TEOAE, nine have subsequently had
normal VROA, another, though not tested is clinically normal. three have hearing
loss with middle ear disease and eight have confirmed sensorineural deafness, all
aided. One infant has died and an infant with Down's syndrome has been adopted
out of the area. It is of interest to note that the eight aided infants are all
of less than 28 weeks gestation. If we restrict analysis to infants with
completed VROA testing, the TEOAE has a 97% negative predictive value for
sensorineural deafness and a 38% positive predictive value. CONCLUSIONS: This
study has highlighted both the prevalence of hearing impairment in the very
premature survivors and difficulties in compliance with a VROA based hearing
screen. We see an advantage in directing resources towards an early screening
test, such as TEOAE, that can be applied while the target population is still
captive.
PMID- 9767511
TI - A randomized controlled trial of two methods for collection of sterile urine in
neonates.
AB - OBJECTIVE: To test whether urethral catheterization (UC) is better than
suprapubic bladder aspiration (SPA) as a method for collection of sterile urine
in neonates. METHODS: Thirty-three babies, requiring sterile collection of urine,
were randomly assigned to either urethral catheterization (n=16), median
gestation 28+/-3.9 weeks, median birth weight 968 g (range 650-4100) or SPA
(n=17), median gestation 26+/-5.6 weeks, median birth weight 926 g (range 771
4070). The primary outcome was success in obtaining urine. Secondary outcomes
were complications and urine culture results. RESULTS: Some urine was obtained in
11 (64.7%) babies in the SPA group and in 13 (81.2%) babies in the catheter
group. Sufficient urine for analysis (>0.5 ml) was obtained in 10 (58.8%) in the
SPA group versus 5 (31.2%) babies in the catheter group. There were more
contaminated specimens in the catheter group but this was not significant in this
small study. CONCLUSIONS: In this small randomized controlled trial urethral
catheterization offered no significant advantage over SPA.
PMID- 9767512
TI - Magnetic resonance imaging evaluation of the pituitary gland and hypothalamus in
thalassaemic children with elevated serum ferritin levels.
AB - OBJECTIVE: Despite modern treatment with hypertransfusion and chelation therapy,
growth retardation continues to be observed in a significant proportion of
thalassaemic children. The underlying reason remains unclear, but hypothalamic
pituitary axis disorder has been implicated. We aimed to assess iron overloading
in the hypothalamus and pituitary gland in thalassaemic children with elevated
serum ferritin, with and without growth retardation. METHODOLOGY: Twelve
thalassaemic children on hypertransfusion and chelation therapy with high serum
ferritin were investigated with magnetic resonance imaging (MRI). Five children,
all over 10 years of age, had growth retardation. Gradient recalled echo sequence
was used to highlight any susceptibility effect that could be due to iron in the
hypothalamus or pituitary gland. RESULT: There was no evidence of abnormal
hypointense signal in the hypothalamus or pituitary gland in the patients
studied, regardless of the presence of growth retardation. CONCLUSION: There was
no apparent characteristic MRI appearances of iron deposition in the hypothalamus
or pituitary gland in thalassaemic children with high serum ferritin.
PMID- 9767513
TI - The musculoskeletal complications of cystic fibrosis.
AB - OBJECTIVE: To determine the spectrum of musculoskeletal complications of cystic
fibrosis (CF) in a paediatric population in Australia. METHOD: Clinical
assessment followed by serology and bone scan on patients attending a specialized
CF clinic. RESULTS: Of 125 patients studied, 21 had musculoskeletal
complications, 17 attributable to CF. Eleven had joint involvement (six
hypertrophic pulmonary osteoarthropathy (HPOA)), one CF arthropathy, two
ciprofloxacin induced arthralgia, one joint contracture following long-line
placement, one chest infection associated arthralgia), four kyphosis (two also
with HPOA) and two thoracic deformity. HPOA was associated with older age, lower
average pulmonary function and lower average Shwachman score. Three patients with
HPOA died within 12 months of reporting symptoms. Kyphosis was also associated
with older age and lower pulmonary function. CONCLUSION: Increasing age with
deteriorating clinical and pulmonary function were associated with a higher
incidence of musculoskeletal involvement. The development of symptomatic HPOA is
a marker of poor prognosis.
PMID- 9767514
TI - Establishment of a normal range of penile length in preterm infants.
AB - RATIONALE: Recognition of micropenis is important because it may be the only
obvious manifestation of pituitary or hypothalamic hormone deficiencies.
Alternatively it may indicate the presence of dysgenetic testicular tissue with
malignant potential. Previously published normal ranges for premature males are
based on small sample sizes, with few infants <30 weeks and none <28 weeks.
SETTING: Intensive and Special Care Nurseries, Royal Women's Hospital, Melbourne,
Victoria. SUBJECTS: 188 consecutive male infants, inborn and outborn, with
gestational age <37 completed weeks were examined in the first week of life. They
included multiple births (n=51) and small for gestational age infants (n=16).
Infants with hypospadias (n=3) or an endocrine disorder (n=1) were excluded from
the study. MANOEUVRE: Stretched penile length was determined by a single examiner
(RT) using a standardized measure. RESULTS: A mean penile length with associated
95% confidence intervals is described for infants between 24 and 36 weeks
inclusive. The relationship between penile length (PL, cm) and gestational age
(GA, weeks) was: PL=2.27+0.16 GA. CONCLUSION: This study confirms the normal
range for penile length of premature male infants 30-36 weeks and defines the
normal range <30 weeks. This should prove useful to paediatricians, paediatric
surgeons and endocrinologists dealing with the increasing number of surviving
male infants <30 weeks in whom penile size is questioned.
PMID- 9767515
TI - Do children need to be monitored after electric shocks?
AB - OBJECTIVE: To determine whether cardiac monitoring is required in children
sustaining electric shock at Australian household voltage. METHODOLOGY: Records
of patients admitted via the Emergency Department of Princess Margaret Hospital
for Children, Perth, Australia, for the period 1968-96 were retrospectively
reviewed. The initial ECG findings of patients with an electric shock were
recorded, and the development of any arrhythmia. RESULTS: Forty-four patients
were identified, 40 of whom had sustained a household electrical injury. One
patient had an abnormal ECG on admission, none developed an arrhythmia and all
survived. CONCLUSIONS: Routine cardiac monitoring is not required after exposure
to Australian household electricity supply if the child is asymptomatic and has a
normal ECG on presentation.
PMID- 9767517
TI - A Chinese girl with Leigh syndrome: effect of botulinum toxin on dystonia.
AB - Leigh syndrome is a form of neurodegenerative disease which is associated with
intracranial infarcts. The diagnosis is made by finding hyperlactacidaemia
together with cerebral infarcts on neuroimaging. We report a 4-year-old Chinese
girl with Leigh syndrome who had several atypical features. She presented with
generalized dystonia and developmental regression. In addition, she suffered from
an unusual feature of bladder dystonia. This patient appeared to be suffering
from respiratory chain complex I deficiency from studies on cultured skin
fibroblasts. Assays for respiratory chain enzymes as well as mitochondrial DNA
point mutations and major deletions in muscle were normal. Dystonia persisted
despite treatments with muscle relaxants and a ketogenic diet. Intramuscular
botulinum toxin resulted in significant relief of dystonia.
PMID- 9767516
TI - Pneumocystis carinii pneumonia: pitfalls of prophylaxis.
AB - Pneumocystis carinii pneumonia (PCP) occurs commonly in immunocompromised
patients. Sulfamethoxazole-trimethoprim (SMX-TMP) is effective prophylaxis,
although PCP may still occur despite apparently adequate use. We report three
cases of PCP which highlight some of the pitfalls of prophylaxis.
PMID- 9767518
TI - History of motion sickness is predictive of childhood migraine.
PMID- 9767519
TI - Hemodialysis access failure: a call to action.
AB - Recent evidence suggests that the cost as well as the morbidity associated with
the maintenance of hemodialysis access is increasing rapidly; currently, the cost
exceeds 1 billion dollars and access related hospitalization accounts for 25% of
all hospital admissions in the U.S.A. This increase in cost and morbidity has
been associated with several epidemiological trends that may contribute to access
failure. These include late patient referral to nephrologists and surgeons, late
planning of vascular access as well as a shift from A-V fistulaes to PTFE grafts
and temporary catheters, which have a higher failure rate. The reasons for this
shift in the types of access is multifactorial and is not explained by changes in
the co-morbidities of patients presenting to dialysis. Surgical preference and
training also appear to play an important role in the large regional variation
and patency rate of these PTFE grafts. We propose a program for early placement
of A-V fistulae, a continuous quality improvement, multidisciplinary program to
monitor access outcome, the development of new biomaterials, and a research plan
to investigate pharmacological intervention to reduce development of stenosis and
clinical interventions to treat those that do develop, prior to thrombosis.
PMID- 9767520
TI - Aquaporins in the kidney: emerging new aspects.
AB - Since 1992 and the discovery of an MIP (major intrinsic protein of lens fiber
cell) homologue protein that selectively permeates water, aquaporin (AQP), there
has been an explosion of research in this field. Early research speculated that
aquaporins played indispensible physiological roles in bacteria and plants, as
well as in mammalian organs such as red blood cells, kidney, eye, brain and lung,
where water transport rapidly takes place. Yet human subjects were identified who
lacked AQP1 and yet had no apparent phenotypical changes clinically. To date 10
aquaporins have been discovered and a plethora of MIP members, and their
prevalance in almost all organisms is a testament to their indispensible roles in
the body, possibly as water and small neutral solute transporting channels. The
recent localization of many different aquaporins in the same organ indicates that
they may work cooperatively, which may partially explain the mystery of their
physiological mechanism. Because the physiological roles of most aquaporins are
currently only speculation, more extensive research is necessary to understand
the exact function of each aquaporin.
PMID- 9767522
TI - Selectivity of endotoxin-induced defect in endothelial calcium mobilization.
AB - BACKGROUND: We hypothesized that endotoxin (LPS) would impair bradykinin (BK)
induced calcium (Ca2+) mobilization in aortic endothelial cells, perhaps due to
cytotoxicity or via stimulation of nitric oxide (NO) synthesis. As well, we
sought to define contributions of LPS-stimulated Ca2+ mobilization to these
effects. METHODS: LPS- or BK-induced increments of intracellular Ca2+ were
assessed by microspectrofluorimetry with fura-2 in passaged bovine aortic
endothelial cells. Time- and dose-dependent effects of LPS exposure (+/-
inhibitors of NO or prostaglandin synthesis) on subsequent BK-induced Ca2+
mobilization and on attached cell counts were determined. RESULTS: LPS (0.1 to
1.0 mg/ml) led to rapid increments of Ca2+, while Ca2+ responses were delayed
following LPS (1 to 10 microg/ml) and lower doses were without effect. By
contrast, LPS more potently (1.0 pg to 1.0 microg/ml) led to dose- and time
dependent impairment of subsequent BK-induced Ca2+ mobilization, with peak effect
at four to six hours, persisting for at least 18 hours. This delayed effect on BK
response was unaltered by inhibition of either NO synthase or cyclooxygenase. The
effect of LPS on BK-responsivity depended importantly on cell confluence, as it
was not observed in subconfluent cells. By contrast, LPS-induced cell detachment,
which was observed only at doses > or = 1.0 microg/ml, did not depend on
confluence. CONCLUSIONS: Different mechanisms lead to endothelial cytotoxicity
and to impaired BK-response following LPS. Only the former effect, occurring at
higher doses, might depend on initial LPS-induced Ca2+ mobilization.
PMID- 9767521
TI - Renal expression of transforming growth factor-beta inducible gene-h3 (beta ig
h3) in normal and diabetic rats.
AB - BACKGROUND: Transforming growth factor-beta (TGF-beta) has been implicated in the
pathogenesis of a number of kidney diseases characterized by glomerulosclerosis
and tubulointerstitial fibrosis. TGF-beta is secreted in a latent form requiring
extracellular modification to become biologically active. TGF-beta inducible gene
h3 (beta ig-h3) is a recently identified TGF-beta-induced gene product. The
present study sought to examine beta ig-h3 expression in normal and diabetic
rats. METHODS: Beta ig-h3, TGF-beta1 and alpha1 (IV) collagen gene expression
were assessed by Northern blot analysis and in situ hybridization in 20 Sprague
Dawley rats, randomly assigned to receive streptozotocin (diabetic, N = 11) or
citrate buffer alone (control, N = 9) and sacrificed eight months later. The
effect of exogenous TGF-beta1 on beta ig-h3 expression was also assessed in
cultured proximal tubular cells. RESULTS: In situ hybridization localized beta ig
h3 gene expression to the juxtaglomerular apparatus and the pars recta (S3
segment) of proximal tubules in both control and diabetic animals. Kidney TGF
beta 1, beta ig-h3 and alpha1 (IV) collagen mRNA from diabetic rats were
increased two- to threefold compared with controls (P < 0.01). There was a
significant correlation between TGF-beta1 and beta ig-h3 gene expression in
kidneys from diabetic rats (r = 0.73, P = 0.01). In addition, beta ig-h3 mRNA
increased in response to exogenous TGF-beta1 in a dose-dependent fashion in
cultured proximal tubular cells. CONCLUSION: These findings support the
hypothesis that biologically active TGF-beta plays a pathogenetic role in
diabetic kidney disease and suggest that beta ig-h3 may be a useful index of TGF
beta1 bioactivity in the kidney.
PMID- 9767524
TI - Serotonin enhances the production of type IV collagen by human mesangial cells.
AB - BACKGROUND: The plasma concentration of 5-hydroxytryptamine (5-HT) in diabetic
patients is higher than that in normal subjects. Since recent reports have
demonstrated the presence of 5-HT2A receptor in glomerular mesangial cells, it is
possible that 5-HT may be involved in the development of diabetic nephropathy
through the 5-HT2A receptor in mesangial cells. Because expansion of the
glomerular mesangial lesion is a characteristic feature of diabetic nephropathy,
we examined the effect of 5-HT on the production of type IV collagen by human
mesangial cells. METHODS: Human mesangial cells were incubated with 5-HT with or
without 5-HT receptor antagonists, protein kinase C (PKC) inhibitor or
transforming growth factor-beta (TGF-beta) antibody. Type IV collagen mRNA and
protein concentration in medium were measured by Northern blot analysis and
enzyme-linked immunosorbent assay (ELISA), respectively. TGF-beta mRNA and
bioactivity in the medium were measured by Northern blot analysis and bioassay
using mink lung epithelial cells, respectively. RESULTS: 5-HT stimulated the
production of type IV collagen by human mesangial cells, which was inhibited by
ketanserin and sarpogrelate hydrochloride, 5-HT2A receptor antagonists, but not
by ondansetron, a 5-HT3 receptor antagonist. 5-HT increased the bioactivities of
both active and total TGF-beta. However, the 5-HT-enhanced production of type IV
collagen was completely inhibited by an anti-TGF-beta antibody. Furthermore, a
PKC inhibitor, calphostin C, inhibited the 5-HT-induced increase in type IV
collagen secretion, and the activity of membrane PKC was increased by 5-HT.
Phorbol ester activated type IV collagen production as well as active and total
TGF-beta. Calphostin C completely inhibited the 5-HT-enhanced activity of active
TGF-beta, but did not inhibit exogenous TGF-beta-induced increase in type IV
collagen secretion. CONCLUSIONS: Our results suggest that 5-HT-enhanced
production of type IV collagen by human mesangial cells is mediated by activation
of PKC and subsequent increase in active TGF-beta activity.
PMID- 9767523
TI - IGF-I binding proteins, IGF-I binding protein mRNA and IGF-I receptor mRNA in
rats with acute renal failure given IGF-I.
AB - BACKGROUND: Recombinant human insulin-like growth factor-I (rhIGF-I) accelerates
recovery from acute renal failure (ARF) in rats. IGF-I acts through the IGF-I
receptor (IGF-IR) and its actions may be modified by IGF-I binding proteins
(IGFBPs). It therefore would be of value to determine the effects of both ARF and
rhIGF-I treatment on serum IGFBPs and mRNA for IGFBPs and IGF-IR. METHODS: Rats
with ARF and sham-operated control rats were randomized to receive rhIGF-I or
vehicle injections thrice daily for 72 to 74 hours starting five hours after
surgery. Serum IGFPBs 1 to 6 were measured serially, and mRNA for IGFBPs 1 to 6
and for IGF-IR were measured in several tissues obtained 72 to 74 hours after
surgery. RESULTS: At 72 to 74 hours, serum IGFBP-1 and IGFBP-2 levels were higher
in rhIGF-I treated rats. Serum IGFBP-3 was affected by both ARF and rhIGF-I.
IGFBP-4 rose transiently only in ARF groups. At 72 to 74 hours, mRNA for several
IGFBPs was reduced in renal cortex of ARF rats. Low mRNA for IGFBP-4 and -6 was
observed in renal medulla of the ARF rats, particularly in comparison to the sham
operated rats receiving vehicle. Renal medullary IGFBP-2 mRNA was decreased in
ARF and sham rats given rhIGF-I as compared to sham animals given vehicle.
Hepatic IGFBP-2 mRNA was higher in both rhIGF-I treated groups versus those given
vehicle. Otherwise, there were no differences in IGFBP mRNAs among the four
groups in lung, heart, and skeletal muscle. IGF-IR mRNA was decreased in renal
cortex and medulla of both ARF groups and was not detected in liver in any group.
CONCLUSIONS: Thus, ARF and rhIGF-I treatment each affected certain serum IGFBPs
and jointly affected some IGFBPs. ARF suppressed gene transcription for renal
cortical and medullary IGF-IR and some IGFBPs. rhIGF-I independently affected
some renal cortical or medullary IGFBP mRNAs. rhIGF-I increased hepatic IGFBP-2
mRNA and serum IGFBP-2. These effects of ARF or rhIGF-I may influence rhIGF-I
actions in rats with ischemic ARF.
PMID- 9767525
TI - Shiga toxin-1 regulation of cytokine production by human proximal tubule cells.
AB - BACKGROUND: Interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor
(TNF) levels are elevated in kidneys of patients with post-diarrheal hemolytic
uremic syndrome (D+HUS) and may contribute to renal dysfunction. The renal
cellular sources of these inflammatory cytokines in D+HUS are largely unknown,
however, the proximal tubule has emerged as a potentially important candidate.
Since Shiga toxin-1 (Stx-1) has been implicated in the genesis of D+HUS, we
examined the effect of Stx-1 on cytokine production by human proximal tubule
cells. METHODS: Stx-1 cytotoxicity, protein synthesis inhibition, and effect on
IL-1, IL-6, and TNF protein release and mRNA levels were determined. The effect
of another protein synthesis inhibitor, cycloheximide (CHX), on these parameters
was also evaluated. RESULTS: Stx-1 greatly increased TNF release and mRNA levels
while CHX, at concentrations that produced similar inhibition of protein
synthesis, had no effect on TNF production. In contrast, Stx-1 and CHX caused
comparable elevations in IL-1 release and mRNA accumulation. Stx-1 and CHX also
stimulated IL-6 mRNA accumulation, but only at concentrations that either were
cytotoxic or substantially blocked protein synthesis. Finally,
lipopolysaccharide, which is likely to be elevated in the circulation of patients
with D+HUS, had no effect alone, but synergized with Stx-1 to increase IL-1
production. CONCLUSIONS: These results indicate that Stx-1 stimulates proximal
tubule inflammatory cytokine production and that this effect is due partially to
nonspecific induction of mRNA levels as well as activation of Stx-1-specific
mechanisms.
PMID- 9767526
TI - Transcriptional activation of transforming growth factor-beta1 in mesangial cell
culture by high glucose concentration.
AB - BACKGROUND: Transforming growth factor-beta (TGF-beta) is an important
hypertrophic and prosclerotic cytokine in the pathogenesis of diabetic
nephropathy. The mechanisms of regulation of the TGF-beta system by high ambient
glucose in kidney cells are incompletely defined. This study examined the
mechanisms of regulation of TGF-beta1 expression by high glucose in murine
mesangial cells (MMCs) in culture. METHODS: MMCs were cultured in either normal
(100 mg/dl) or high (450 mg/dl) D-glucose concentration. Total TGF-beta1 protein
secretion and bioactivity, mRNA expression and stability, and gene transcription
rate were measured; promoter-reporter chloramphenicol acetyltransferase (CAT)
assays and electrophoretic mobility shift assay (EMSA) were performed to
investigate the presence of putative glucose-response elements. RESULTS: Raising
the ambient D-glucose concentration for 72 hours increased TGF-beta1 bioactivity
in cell culture medium by 47% and total TGF-beta1 secretion by approximately 90%.
Northern analysis demonstrated that the steady-state TGF-beta1 mRNA level was
increased nearly twofold after 48 hours of growth in high glucose. This increase
was not due to increased stability, as the half-life of the message was
approximately five hours in both normal and high glucose conditions.
Transcriptional activity of the TGF-beta1 gene (nuclear run-on assay) was
increased by 73% in cells grown in high glucose for 24 hours. Transiently
transfected MMCs with CAT constructs containing varying lengths of the murine TGF
beta1 promoter demonstrated that high glucose selectively increased the
expression of only one of the constructs, pA835. Sequence inspection revealed the
presence of a putative glucose responsive element, CACGTG, within this construct.
High glucose in MMC culture for 24 hours increased nuclear protein binding to a
probe containing this element when analyzed using EMSA. CONCLUSIONS: High glucose
stimulates total TGF-beta1 protein production and bioactivity as well as the
steady-state level of TGF-beta1 mRNA. The latter effect is due primarily to
stimulation of gene transcription rate rather than message stability.
Transcriptional activation by high glucose may involve a region in the TGF-beta1
promoter containing a putative glucose-response element.
PMID- 9767527
TI - Shiga toxin 1 elicits diverse biologic responses in mesangial cells.
AB - BACKGROUND: Shiga toxin 1 (Stx1) is a causative agent in hemolytic uremic
syndrome (HUS). Its receptor, the glycosphingolipid globotriaosylceramide (Gb3),
is expressed on cultured human endothelial and mesangial cells. Mesangial cell
injury in HUS ranges from mild cellular edema to severe mesangiolysis and
eventual glomerulosclerosis. We hypothesized that, in addition to endothelial
cells, mesangial cells are targets of Stx1. METHODS: Human mesangial cells were
exposed to Stx1. Protein synthesis was measured using [35S]-methionine/cysteine.
Cell viability was measured as the lysosomal uptake of Neutral Red. Monocyte
chemotactic peptide (MCP-1) mRNA and protein were analyzed by Northern blotting
and ELISA. RESULTS: Stx1 (0.25 to 2500 ng/ml) resulted in a dose-dependent
inhibition of protein synthesis. This effect of Stx1 was potentiated by
preincubation of the cells with interleukin-1alpha (IL-1alpha; 2 ng/ml) or tumor
necrosis-alpha (TNF-alpha; 500 U/ml). Stx1 had little effect on mesangial cell
viability during the first 24 hours of exposure to Stx1. However, prolonged
incubation with Stx1 for 48 and 72 hours resulted in a 68% and 80% decrease in
cell-viability, respectively. Stx1 elicited a dose and time dependent increase in
the levels of MCP-1 mRNA, an effect that was potentiated by preincubation with IL
1alpha. CONCLUSION: These data indicate that mesangial cells are susceptible to
the effects of Stx1 in vitro. Stx1 exerts a spectrum of biologic effects on
mesangial cells ranging from activation of chemokine genes to a lethal toxic
injury. Immunoinflammatory cytokines potentiate the effects of Stx1. Thus,
glomerular pathology in HUS may also result from a direct effect of Stx1 on
mesangial cells.
PMID- 9767528
TI - Potential role of hepatocyte growth factor in the maintenance of renal structure:
anti-apoptotic action of HGF on epithelial cells.
AB - BACKGROUND: Mesangial cells (MC) are known to secrete various vasoactive
substances that may control endothelial and epithelial cell growth. Therefore,
the cell-cell interactions among these cells may be important in the control of
renal function. However, the exact mechanisms of maintaining the cell-cell
interactions are not yet understood. We have focused on the role of hepatocyte
growth factor (HGF) in the regulation of cell-cell interactions, since HGF has
many protective functions in the kidney. To investigate the role of HGF in renal
injury, we examined (1) the effects of HGF on epithelial injury induced by serum
deprivation, and (2) the role of local HGF production in the maintenance of renal
structure. METHODS: Apoptotic changes in epithelial cells were assessed by
nuclear morphology and DNA fragmentation assay. Transfection of human HGF vector
into epithelial cells was performed by a highly efficient viral-liposome method.
The effects of secreted HGF on the growth of renal cells were examined using a co
culture system. RESULTS: The addition of recombinant HGF (rHGF) stimulated the
growth of rat and porcine epithelial cells. Moreover, the decrease in number of
epithelial cells by serum deprivation was significantly attenuated by rHGF.
Interestingly, apoptotic changes in epithelial cells induced by serum deprivation
were also significantly attenuated by rHGF (P < 0.01). As a model of gene
therapy, the effects of overexpression of human HGF gene in epithelial cells on
apoptosis induced by serum deprivation were examined. Transfection of human HGF
vector into epithelial cells also attenuated epithelial cell death induced by
serum deprivation through the inhibition of apoptosis, accompanied by increased
HGF production (P < 0.01). In addition, HGF also prevented endothelial injury
induced by tumor necrosis factor-alpha and dexamethasone. Given the presence of a
local HGF system, we measured local HGF secreted from renal cells. Immunoreactive
HGF was observed in the conditioned medium of MC, but not epithelial cells, while
the specific receptor of HGF, c-met, was expressed in epithelial cells. Of
importance, co-culture of MC with epithelial cells resulted in a significant
increase in number of epithelial cells, which was significantly abolished by
neutralizing anti-HGF antibody. CONCLUSIONS: Overall, these results demonstrate
that local production of HGF in MC may maintain the growth of epithelial and
endothelial cells through its anti-apoptotic action.
PMID- 9767529
TI - Therapeutic concentrations of cyclosporine A, but not FK506, increase P
glycoprotein expression in endothelial and renal tubule cells.
AB - BACKGROUND: The immunosuppressive drugs cyclosporine A (CsA) and tacrolimus
(FK506) are extruded from cells by the multidrug resistance P-glycoprotein (P
gp), an efflux pump for drugs and xenobiotics, which may limit their therapeutic
effectiveness and/or incidence of toxic side effects. In the present study, we
investigated the effect of therapeutic concentrations of CsA and FK506 on the
expression of P-gp in cultured endothelial and proximal tubule cells. METHODS: P
gp expression in human arterial endothelial (HAEC) and rat proximal tubule cells
(RPTC) was determined by immunoblotting and immunocytochemistry, and correlated
with P-gp-mediated transport by measuring the intracellular accumulation of the
fluorescent probe calcein. RESULTS: Following incubation of HAEC with therapeutic
concentrations of 0.1 to 1.6 microM CsA up to seven days, P-gp expression
increased in a time- and concentration-dependent manner, maximally to 291 +/- 42%
of controls with 0.8 microM CsA for seven days. Similar effects of CsA were
observed in RPTC. In contrast, therapeutic concentrations of FK506 (0.01 to 0.2
microM up to 7 days) did not change P-gp expression in either cell type, though
at higher, supratherapeutic concentrations of FK506 (0.6 to 1.2 microM) P-gp
expression was also increased. Immunocytochemistry revealed increased P-gp
expression in the plasma membrane of HAEC and RPTC treated with 0.8 microM CsA,
which was reflected by a decrease of P-gp-mediated accumulation of calcein in
both cell types. CONCLUSIONS: The data suggest that the induction of P-gp
expression in HAEC and RPTC at concentrations of CsA or FK506 above 0.5 microM is
part of the protective answer of cells to toxic concentrations of the drugs and
could therefore interfere with the therapeutic effectiveness of CsA in vivo.
PMID- 9767530
TI - Dietary salt regulates expression of Tamm-Horsfall glycoprotein in rats.
AB - BACKGROUND: Tamm-Horsfall glycoprotein (THP) is a unique protein that is produced
exclusively by cells of the thick ascending limb of Henle's loop (TALH). This
study examined whether dietary salt altered renal THP production. METHODS: Male
Sprague-Dawley rats were examined on days 1, 4, and 15 following placement in
metabolic cages on diet that contained 0.3%, 1.0% or 8.0% NaCl. THP expression
was quantified using Northern hybridization and Western blotting analysis.
RESULTS: An increase in dietary salt produced sustained increases in relative
steady-state mRNA and protein levels of THP in the kidney. Addition of
furosemide, but not chlorothiazide, to animals on the 8.0% NaCl diet further
augmented steady-state mRNA levels of THP. CONCLUSIONS: An increase in dietary
salt and the loop diuretic, furosemide, increased expression of THP in the rat.
The data support the involvement of this unique protein in the function of the
TALH during changes in dietary salt. These findings also suggest that restriction
of dietary salt may be beneficial in cast nephropathy in multiple myeloma and
recurrent nephrolithiasis, two diseases in which THP can play an important
pathogenetic role.
PMID- 9767531
TI - Contribution of tubular injury to loss of remnant kidney function.
AB - BACKGROUND: The remnant kidney model has been widely used to identify mechanisms
responsible for the progression of renal disease. However, the structural changes
associated with progressive loss of function in this model have not been well
characterized. METHODS: Kidney function and structure were assessed at 10 weeks
(REM 10) and 25 weeks (REM 25) after five-sixths renal ablation and in control
rats (Control). Serial sections were examined to relate glomerular and tubular
structure in individual nephrons. RESULTS: Remnant kidney function declined
between 10 and 25 weeks after ablation (GFR 0.90 +/- 0.34 vs. 0.23 +/- 0.07
ml/min, REM 10 vs. REM 25, P < 0.05). This decline in function was associated
with an increase in the prevalence of globally sclerotic glomeruli (14 +/- 10 vs.
0 +/- 0 vs. 0 +/- 0%, REM 25 vs. REM 10 vs. Control, P < 0.05 REM 25 vs. REM 10
and Control). The decline in remnant kidney function between 10 and 25 weeks was
also associated with the appearance of glomeruli that were atubular (48 +/- 14
vs. 9 +/- 8 vs. 3 +/- 5%, REM 25 vs. REM 10 vs. Control, P < 0.05 REM 25 vs. REM
10 and Control) or connected to atrophic proximal tubule segments (26 +/- 10 vs.
11 +/- 6 vs. 1 +/- 2%, REM 25 vs. REM 10 vs. Control, P < 0.05 all comparisons).
Atubular glomeruli, which usually had open capillary loops available for
filtration, were more numerous than globally sclerotic glomeruli at 25 weeks
after ablation. CONCLUSIONS: These findings indicate that tubular injury
contributes to progressive loss of renal function following reduction in nephron
number.
PMID- 9767532
TI - Distinct contribution of Fc receptors and angiotensin II-dependent pathways in
anti-GBM glomerulonephritis.
AB - BACKGROUND: The contribution of antibody and/or immune-complex to the
pathogenesis of immunologically-mediated glomerulonephritis is not fully
understood, although it has been recently clarified that Fc receptors (FcRs) play
critical roles in the inflammatory cascade. We therefore re-evaluated the
classical model of glomerulonephritis, anti-glomerular basement membrane antibody
induced glomerulonephritis (Anti-GBM GN), from the standpoint of FcRs and also
investigated the residual FcR-independent mechanisms. METHODS: We adopted an Anti
GBM GN mouse model that has two strains deficient in the FcR gamma chain [gamma(
/-)] or Fc gammaRIIB [RII(-/-)], and analyzed functional (urinary protein, serum
creatinine, BUN) and pathological changes of the glomeruli. For the analyses of
FcR-independent mechanisms, several doses of nephrotoxic serum were applied, and
then mice were treated either with cobra venom factor or an angiotensin II type 1
receptor antagonist in gamma(-/-) mice. RESULTS: In gamma(-/-) mice, renal
injuries were dramatically attenuated with an absence of polymorphonuclear cell
(PMN) influx, while RII(-/-) mice suffered accelerated glomerular injuries in
spite of a normal PMN influx. In the absence of FcR-dependent effects in gamma(-/
) mice, the FcR-independent pathway lead to chronic renal damage characterized by
mesangial proliferation and progressive expansion of mesangial area, with
monocyte/macrophage accumulation and with the expression of alpha smooth muscle
actin in the mesangial cells and interstitium. Those injuries in gamma(-/-) mice
were not attenuated by the decomplementation, but completely abolished by using
an angiotensin II type 1 receptor antagonist. CONCLUSIONS: Our results clearly
demonstrate that FcRs play a pivotal role in Anti-GBM GN, especially in its acute
phase. We further clarified the existence of FcR and complement-independent but
antibody-dependent pathway. Furthermore, we found that those pathological changes
were strongly related to the renin-angiotensin system.
PMID- 9767534
TI - Regulation of survival and death of mesangial cells by extracellular matrix.
AB - BACKGROUND: Cell-matrix interactions exert major effects on such phenotypic
features as cell growth and differentiation. Apoptosis is an active form of cell
death that is crucial for maintaining the appropriate number of cells as well as
the organization of tissue. Recently, it has been suggested that apoptosis of the
mesangial cells (MC) is important in glomerular remodeling after injury. The MC
are surrounded by an extracellular matrix (ECM) in vivo. Since in disease
conditions the mesangial matrix is altered quantitatively and qualitatively, it
is of interest to determine whether cell-matrix interactions may influence
apoptosis of the MC. METHODS: We first investigated the differences in the
susceptibility to apoptotic stimuli of the MC cultured on various ECM components
(type I collagen, fibronectin, basement membrane matrix). We then determined
whether the inhibition of MC-matrix interactions would affect apoptosis. Finally,
interactions between MC and matrix were disrupted by the inhibition of beta1
integrin expression with antisense oligonucleotides (ODN). RESULTS: When MC were
cultured on type I collagen or fibronectin and deprived of serum for eight hours,
the extracted DNA from the MC demonstrated an internucleosomal ladder pattern on
gel electrophoresis that constituted the biochemical characteristic of apoptosis.
However, no ladder pattern was apparent when MC were cultured on basement
membrane matrix. The attachment of cells was completely inhibited when the MC
were cultured on agarose-coated dishes for 24 hours. Gel electrophoresis of DNA
extracted from these cells showed a ladder pattern. However, the MC attached to
the substratum did not show any apoptosis. MC showed an increase in apoptotic
cell death after treatment with antisense ODN against beta1-integrin molecule.
CONCLUSIONS: These results indicate that normal ECM may prevent the MC from
undergoing apoptosis and serve as a survival factor for MC. Signals from ECM that
prevent apoptosis may be mediated by beta1-integrin molecules.
PMID- 9767533
TI - Regulation of smooth muscle alpha-actin expression and hypertrophy in cultured
mesangial cells.
AB - BACKGROUND: Mesangial cells during embryonic development and glomerular disease
express smooth muscle alpha-actin (alpha-SMA). We were therefore surprised when
cultured mesangial cells deprived of serum markedly increased expression of alpha
SMA. Serum-deprived mesangial cells appeared larger than serum-fed mesangial
cells. We hypothesized that alpha-SMA expression may be more reflective of
mesangial cell hypertrophy than hyperplasia. METHODS: Human mesangial cells were
cultured in medium alone or with fetal bovine serum, thrombin, platelet-derived
growth factor-BB (PDGF-BB) and/or transforming growth factor-beta1 (TGF-beta1).
Alpha-SMA expression was examined by immunofluorescence, Western blot, and
Northern blot analysis. Cell size was analyzed by forward light scatter flow
cytometry. RESULTS: Alpha-SMA mRNA was at least tenfold more abundant after three
to five days in human mesangial cells plated without serum, but beta-actin mRNA
was unchanged. Serum-deprived cells contained 5.3-fold more alpha-SMA after three
days and 56-fold more after five days by Western blot. Serum deprivation also
increased alpha-SMA in rat and mouse mesangial cells. The effects of serum
deprivation on alpha-SMA expression were reversible. Mesangial cell mitogens,
thrombin or PDGF-BB, decreased alpha-SMA, but TGF-beta1 increased alpha-SMA
expression and slowed mesangial cell proliferation in serum-plus medium. Flow
cytometry showed that serum deprivation or TGF-beta1 treatment caused mesangial
cell hypertrophy. PDGF-BB, thrombin, or thrombin receptor-activating peptide
blocked hypertrophy in response to serum deprivation. CONCLUSIONS: We conclude
that increased alpha-SMA expression in mesangial cells reflects cellular
hypertrophy rather than hyperplasia.
PMID- 9767535
TI - Measurement of the kinetics of protein uptake by proximal tubular cells using an
optical biosensor.
AB - BACKGROUND: The affinity and specificity of protein reabsorption by proximal
tubular cells have been investigated using techniques for monitoring endocytosis,
demonstrating a high capacity but low affinity process. It is not known whether
uptake is through binding to a single binding site/receptor with differing
affinities, or if there are several classes of binding sites receptors, each
specific for differing proteins or groups, such as, high or low molecular weight
proteins. METHODS: We have developed a novel technique for analyzing the kinetics
of protein binding to tubular cells using a optical biosensor system. We have
studied the binding of cultured LLCPK cells to albumin and RBP immobilized onto
the sensor. By adding increasing concentrations of competing proteins [varying in
molecular weight from 66,000 to 11,800 D and pI from 4.6 to 9.2 as represented by
albumin, alpha1-microglobulin (alpha1M), retinol binding protein (RBP), cystatin
C and beta2-microglobulin (beta2m)], specific and inhibitable cell binding was
demonstrated. RESULTS: Equilibrium constants, KA, could be calculated from the
reciprocal of the protein concentration causing 50% inhibition in binding rate.
These were: albumin = 8.0 x 10(4) M(-1), alpha1M = 2.0 x 10(5) M(-1), RBP = 2.7 x
10(4) M(-1), cystatin C = 2.0 x 10(4) M(-1), beta2m = 4.2 x 10(3) M(-1). There
were no significant differences between the measured KA's whether RBP or albumin
were immobilized on the surface. CONCLUSIONS: All the proteins gave similar
shaped inhibition profiles, suggesting that there is one binding site/receptor
for all proteins studied, regardless of molecular weight or charge, but there are
differing affinities for each protein.
PMID- 9767536
TI - Mechanisms through which high glucose concentration raises [Ca2+]i in renal
proximal tubular cells.
AB - BACKGROUND: The basal levels of cytosolic calcium ([Ca2+]i) of renal proximal
tubular cells of rats with streptozotocin-induced diabetes are elevated. It is
possible that this phenomenon is mediated by the hyperglycemia, which may cause
both increased calcium influx into and/or decreased calcium efflux out of these
cells. METHODS: We examined whether high glucose concentration in vitro causes
acute rise in [Ca2+]i of freshly isolated renal proximal tubular cells and
explored the pathways that are involved in such an event. RESULTS: There were
dose and time dependent increments in [Ca2+]i of renal proximal tubular cells
exposed to high concentrations of glucose. A similar effect was observed with
equimolar concentrations of mannitol or choline chloride but not urea. A
substantial part of the rise in [Ca2+]i was inhibited when the media contained
verapamil, nifedipine, amlodipine or ryanodine and when the cells were placed in
a calcium free media. Inhibitors of G protein(s) (GDPbetaS or pertussis toxin),
inhibitors of cAMP-protein kinase A pathway (RpcAMP or H-89), inhibitors of
protein kinase C (staurosporine or calphostin) and inhibitor of Na+-H+ exchanger
(HOE 694) blocked the rise in a dose dependent manner. High glucose concentration
also caused a decrease in ATP content of these cells and a reduction in the Vmax
of their Ca2+ATPase. CONCLUSIONS: The results are consistent with the formulation
that the osmotic activity (cell shrinkage) of the high glucose concentration may
activate a stretch receptor with subsequent stimulation of various cellular
pathways including G protein(s), cAMP-protein kinase A and phospholipase C
systems and calcium channels. Activation of these cellular pathways permits both
calcium influx into renal tubular cells and mobilization of calcium from their
intracellular stores. Further, a decrease in calcium efflux secondary to the
reduction in the Vmax of Ca2+ ATPase may occur. It is possible that the rise in
[Ca2+]i is critical for the stimulation of the events that lead to restoration of
cell volume to normal.
PMID- 9767537
TI - Localization of the ROMK potassium channel to the apical membrane of distal
nephron in rat kidney.
AB - BACKGROUND: The apical potassium (K+) channels mediate K+ recycling in thick
ascending limb (TAL) and K+ secretion in cortical collecting duct (CCD).
Recently, the cDNAs for a family of renal K+ channels, ROMK1, -2 and -3, were
identified. Based on the biophysical properties and mRNA distribution, it is
believed that these ROMK cDNAs encode the apical K+ channels of TAL and CCD.
However, the information for cellular and subcellular localization of the ROMK
proteins in these tubules is still not available. METHODS: Paraffin or frozen
kidney sections from adult Sprague-Dawley rats were stained by polyclonal
antibodies against the N- and C-terminal domain of ROMK. Immunoreactive staining
was visualized by color development from horseradish peroxidase reaction.
Membrane homogenates from kidney were analyzed by Western blot analysis. RESULTS:
The polyclonal antibodies against cytoplasmic epitope of ROMK recognized a
approximately 42 kD protein in the membrane homogenates from kidney, but not from
liver. Staining by immunocytochemistry revealed that ROMK channels were localized
to the apical membranes of the distal nephron in cortex and outer medulla,
including thick ascending limb and collecting tubule. ROMK staining was absent in
glomerulus, proximal tubule and inner medulla. Double staining of the tissue
section with both ROMK-specific and H+-ATPase-specific antibodies revealed
labeling of ROMK in the principal cells of the collecting tubules. CONCLUSIONS:
These results further strengthen the idea that ROMK channels play important roles
in the recycling of K+ in TAL and the secretion of K+ in CCD.
PMID- 9767538
TI - Parathyroid hormone and dietary phosphate provoke a lysosomal routing of the
proximal tubular Na/Pi-cotransporter type II.
AB - BACKGROUND: A decrease of proximal tubular reabsorption of phosphate (Pi), which
can be provoked by parathyroid hormone (PTH) or by a high Pi-diet, has been shown
to correlate with a decrease of the number of type II Na/Pi-cotransporters
residing in the brush border membrane. While both PTH and a high Pi-diet lead to
an internalization of type II cotransporters, the further cellular routing of
internalized cotransporters has not been established unequivocally. METHODS: To
prevent lysosomal degradation, rats were treated with leupeptin prior to the
injection of PTH or feeding acutely with a high Pi-diet. Kidney cortex were
recovered and used for immunohistochemistry. In parallel, brush border membranes
and lysosomes were isolated and analyzed by Western blotting. RESULTS: Under both
conditions (PTH and high Pi-diet), a strong overlap of internalized type II
cotransporters with the late endosomes/lysosomes was observed by
immunohistochemistry. In agreement, the content of type II Na/Pi-cotransporters
was increased in lysosomes isolated from the corresponding tissues. CONCLUSIONS:
These results suggest that in proximal tubular cells type II Na/Pi-cotransporters
internalized due to the action of PTH and acute high Pi-diet are routed to the
lysosomes, and likely do not enter a recycling compartment.
PMID- 9767539
TI - Colonic H+-K+-ATPase is induced and mediates increased HCO3- reabsorption in
inner medullary collecting duct in potassium depletion.
AB - BACKGROUND: Potassium depletion increases HCO3- reabsorption in outer medullary
collecting duct (OMCD) by activation of colonic (c) H-K-ATPase (HKA). The purpose
of the current experiments was to examine the role of the isoforms of HKA in HCO3
reabsorption by terminal inner medullary collecting duct (IMCD) cells in
potassium depletion. METHODS: Sprague-Dawley rats were fed a potassium-free diet
and studied after 8 to 10 days. mRNA expression of HKA isoforms in terminal
portion of inner medulla was examined and correlated with HCO3- reabsorption in
the terminal IMCD. RESULTS: Gastric (g) HKA mRNA decreased whereas colonic (c)
HKA mRNA expression was heavily induced in terminal portion of inner medulla in
potassium depleted rats. Net HCO3- flux (JtCO2) in terminal IMCD increased in
potassium depletion (4.56 to 7.06 pmol/min/mm tubule length, P < 0.001). In
normal rats, 1 mM ouabain in perfusate had no effect on JtCO2, whereas 10 microM
Schering 28080 (SCH) decreased JtCO2 to 2.4 (P < 0.002). In KD rats, 1 mM ouabain
decreased JtCO2 to 4.9 (P < 0.005) and 10 microM SCH decreased JtCO2 to 3.3 (P <
0.001). However, the inhibitory effects of SCH and ouabain on JtCO2 in potassium
depleted animals were not additive. CONCLUSIONS: The data indicate that gHKA is
suppressed whereas cHKA is induced in potassium depletion and mediates increased
HCO3- reabsorption in terminal IMCD. The results further indicate that cHKA in
vivo is sensitive to both SCH and ouabain.
PMID- 9767540
TI - Nature of glomerular dysfunction in pre-eclampsia.
AB - BACKGROUND: Pre-eclampsia is characterized by hypertension, proteinuria and
edema. Simultaneous studies of kidney function and structure have not been
reported. We wished to explore the degree and nature of glomerular dysfunction in
pre-eclampsia. METHODS: Physiologic techniques were used to estimate glomerular
filtration rate (GFR), renal plasma flow and afferent oncotic pressure
immediately after delivery in consecutive patients with pre-eclampsia (PET; N =
13). Healthy mothers completing an uncomplicated pregnancy served as functional
controls (N = 12). A morphometric analysis of glomeruli obtained by biopsy and
mathematical modeling were used to estimate the glomerular ultrafiltration
coefficient (Kf). Glomeruli from healthy female kidney transplant donors served
as structural controls (N = 8). RESULTS: The GFR in PET was depressed below the
control level, 91 +/- 23 versus 149 +/- 34 ml/min/1.73 m2, respectively (P <
0.0001). In contrast, renal plasma flow and oncotic pressure were similar in the
two groups (P = NS). A reduction in the density and size of endothelial fenestrae
and subendothelial accumulation of fibrinoid deposits lowered glomerular
hydraulic permeability in PET compared to controls, 1.81 versus 2.58 x 10(-9)
m/sec/PA. Mesangial cell interposition also curtailed effective filtration
surface area. Together, these changes lowered the computed single nephron Kf in
PET below control, 4.26 versus 6.78 nl/min x mm Hg, respectively. CONCLUSION: The
proportionate (approximately 40%) depression of Kf for single nephrons and GFR
suggests that hypofiltration in PET does not have a hemodynamic basis, but is a
consequence of structural changes that lead to impairment of intrinsic glomerular
ultrafiltration capacity.
PMID- 9767541
TI - Adenovirus-mediated kallikrein gene delivery reverses salt-induced renal injury
in Dahl salt-sensitive rats.
AB - BACKGROUND: The tissue kallikrein-kinin system has been shown to play a role in
cardiac and renal functions. In this study, we investigated the ability of
kallikrein gene delivery to reverse salt-induced cardiac hypertrophy and renal
injury in Dahl salt-sensitive rats. METHODS: Adenovirus harboring the human
tissue kallikrein gene, Ad.CMV-cHK, was delivered intravenously into Dahl salt
sensitive rats suffering from hypertension, cardiac hypertrophy and renal damage
induced by a high salt diet (4% NaCl) for four weeks. RESULTS: Expression of
human kallikrein mRNA was detected in rat kidney, heart, aorta and liver, and
immunoreactive human kallikrein levels were measured in the serum and urine of
rats receiving gene delivery. A single injection of Ad.CMV-cHK caused a
significant reduction of blood pressure for more than two weeks. Kallikrein gene
transfer caused left ventricular mass reduction and elevated glomerular
filtration rate, renal blood flow, urinary excretion, urinary kinin,
nitrite/nitrate content, cGMP and cAMP levels. Morphological investigations
showed that kallikrein gene transfer caused a significant reversal in salt
induced tissue and organ damage. In the heart, cardiac hypertrophy and fibrosis
were reduced, and in the kidney, both glomerular sclerotic lesions and tubular
damage were reversed. CONCLUSIONS: Adenovirus-mediated kallikrein gene delivery
is effective in reversing salt-induced cardiac hypertrophy and renal injury in
Dahl-salt sensitive rats.
PMID- 9767542
TI - Peripheral microvascular parameters in the nephrotic syndrome.
AB - BACKGROUND: Peripheral edema, in combination with severe proteinuria and low
serum albumin levels, is pathognomonic of the nephrotic syndrome, yet the exact
mechanism of its formation is unknown. Two of the most important of the factors
in Starling's forces controlling fluid filtration across the capillary have
hitherto not been studied in nephrotic subjects. METHODS: The hydrostatic
capillary pressure at the finger nail-fold in actively nephrotic subjects and age
and sex matched controls was studied, using direct puncture of the apex of the
capillary under video microscopy, and a servonulling apparatus to give a direct
measurement of capillary pressure. Capillary filtration capacity (CFC) at the
calf was measured noninvasively by a modern derivative of the technique of
mercury strain gauge plethysmography. Fifteen nephrotic subjects with a variety
of underlying pathological lesions, and age matched controls were studied.
RESULTS: Contrary to the assumption of the "overflow" hypothesis of edema
formation, there was no evidence of capillary hypertension. The capillary
pressure showed no difference between nephrotic subjects and controls: median
(range) of 17.6 (12.0 to 24.2) compared with 17.3 (9.0 to 21.6) mm Hg, P = NS.
CFC was significantly higher in nephrotic subjects than controls [5.23 (3.28 to
8.52) x 10(-3) versus 3.55 (2.43 to 5.28) x 10(-3) ml/min/100 g/mm Hg, P < 0.01].
CONCLUSIONS: An increase in CFC provides a potentially novel mechanism
contributing at least in part to the formation of peripheral edema in the
nephrotic syndrome.
PMID- 9767543
TI - Low leptin gene expression and hyperleptinemia in chronic renal failure.
AB - BACKGROUND: The ob gene product leptin is thought to be a key regulator of food
intake and body weight. Patients having advanced chronic renal failure (CRF) have
markedly higher serum leptin levels. It is not known whether the increase in
leptin levels in CRF is caused by a decreased plasma clearance and/or increased
production. METHODS: In the present study serum leptin levels and glomerular
filtration rate (GFR) were measured in 219 patients having various degrees of
renal failure. In addition, serum leptin levels, C-reactive protein (CRP), body
composition (by dual-energy x-ray absorptiometry) and ob gene expression (by in
situ hybridization histochemistry) were determined in 15 patients with advanced
CRF. Seven of the patients were re-evaluated following 12 months of peritoneal
dialysis (PD) treatment. RESULTS: Serum leptin levels correlated negatively to
GFR (r = -0.26; P < 0.0001). The ob gene expression was significantly lower in
patients with CRF than in healthy controls. A negative correlation between serum
leptin levels and ob gene expression (r = -0.66; P < 0.05) was found in patients
with CRP < 25 mg/liter. The ob gene expression (20.0 +/- 1.8 vs. 15.0 +/- 1.0
nCi/g; P < 0.05) was significantly higher in 5 patients with CRP > 25 mg/liter
than in 10 patients with CRP < 25 mg/liter. Following 12 months of PD, the amount
of body fat increased by 30% while the ob gene expression remained unchanged.
CONCLUSION: The present study shows a correlation between serum leptin levels and
GFR, and our results suggest that elevated leptin levels, due to a decreased
plasma clearance, down-regulate the expression of the ob gene. We also found that
an ongoing inflammation stimulates ob gene expression in patients with CRF.
Therefore, it is suggested that the hyperleptinemia induced feedback inhibition
of ob gene expression is overcome by inflammatory cytokines.
PMID- 9767544
TI - Circadian variations of renal sodium handling in patients with orthostatic
hypotension.
AB - BACKGROUND: Sodium wasting during the night has been postulated as a potential
pathophysiological mechanism in patients suffering from orthostatic hypotension
due to severe autonomic deficiency. METHODS: In this study, the diurnal
variations in creatinine clearance, sodium excretion and segmental renal tubular
handling of sodium were evaluated in 18 healthy subjects and 20 young patients
with orthostatic hypotension (OH). In addition, 24-hour ambulatory blood pressure
and the neuro-hormonal response to changes in posture were determined. The
patients and their controls were studied on a free sodium intake. In a second
protocol, 10 controls and 10 patients were similarly investigated after one week
of a high salt diet (regular diet + 6 g NaCl/day). RESULTS: Our results
demonstrate that, in contrast to normal subjects in whom no significant changes
in glomerular filtration, sodium excretion and segmental sodium reabsorption were
observed throughout the day, patients with OH were characterized by a significant
increase in glomerular filtration rate during the nighttime (P = 0.03) and
significant increases in urinary lithium excretion (P < 0.05) and lithium
clearance (P = 0.05) during the night, suggesting a decreased proximal
reabsorption of sodium. On a high sodium diet, the symptoms of orthostatic
hypotension and the circadian variations in sodium reabsorption were
significantly blunted. CONCLUSIONS: These results suggest that, while the patient
is in a supine position the effective blood volume of those with OH becomes
excessive due to the increased venous return. Hence, the kidney responds with an
increase in glomerular filtration and a relative escape of sodium from the
proximal tubular segments. These circadian variations in renal sodium handling
may contribute to the maintenance of the orthostatic syndrome.
PMID- 9767545
TI - Effects of an ACE inhibitor/calcium antagonist combination on proteinuria in
diabetic nephropathy.
AB - BACKGROUND: The degree of proteinuria in patients with diabetes correlates
strongly with both an increase in progression of nephropathy as well as
cardiovascular events. Moreover, post hoc analyses of recent clinical trials
support the concept that reductions of blood pressure and proteinuria correlate
with a slowed progression of nephropathy. Both angiotensin converting enzyme
(ACE) inhibitors and the nondihydropyridine calcium antagonists, (non-DHPCAs)
reduce both arterial pressure and proteinuria in those with diabetic nephropathy.
METHODS: The present randomized, open label, parallel group designed study tests
the hypothesis that, at similar levels of blood pressure, the combination of an
ACE inhibitor, trandolapril (T) with the non-DHPCA, verapamil (V) produces a
greater reduction in proteinuria over either agent alone at one year. Thirty
seven participants, mean age 59.6 +/- 5.8 years, with nephropathy (baseline
creatinine 1.4 +/- 0.3 mg/dl and proteinuria of 1342 +/- 284 mg/dl) secondary to
type 2 diabetes completed the study. Doses of drug were titrated in each group
over eight weeks to achieve a goal blood pressure of < 140/90 mm Hg. All
participants were counseled to ingest a sodium diet of < 120 mEq/day. RESULTS:
Proteinuria reduction from baseline was significantly greater in the T+V group
compared to either T alone (-33 +/- 8%, T vs. -62 +/- 10%, T+V; P < 0.001) or V
alone (-27 +/- 8%, V vs. -62 +/- 10%, T+V; P < 0.001). No significant differences
in either glomerular filtration rate, arterial pressure, fasting blood glucose or
urinary sodium excretion were noted at one year. The mean daily dose of the
individual components of T+V (2.9 +/- 0.8 mg, T/219 +/- 21.1 mg V) was
significantly lower than the dose of either T alone 5.5 +/- 1.1 mg/day (P < 0.01)
or V alone 314.8 +/- 46.3 mg, given in two divided doses (P < 0.01). CONCLUSION:
These data support the concept that the combination of an ACE inhibitor with a
non-DHPCA reduce proteinuria to a greater extent than either agent alone. This
added antiproteinuric effect occurs at lower doses of each drug and is
independent of further reductions in arterial pressure. These findings could have
ramifications for slowing renal disease progression in patients with nephropathy
from type 2 diabetes.
PMID- 9767546
TI - Autoxidation products of both carbohydrates and lipids are increased in uremic
plasma: is there oxidative stress in uremia?
AB - BACKGROUND: Advanced glycation end products (AGEs), formed by non-enzymatic
glycation and oxidation (glycoxidation) reactions, have been implicated in the
pathogenesis of several diseases, including normoglycemic uremia. AGE research in
uremia has focused on the accumulation of carbohydrate-derived adducts generated
by the Maillard reaction. Recent studies, however, have demonstrated that one
AGE, the glycoxidation product carboxymethyllysine (CML), could be derived not
only from carbohydrates but also from oxidation of polyunsaturated fatty acids in
vitro, raising the possibility that both carbohydrate and lipid autoxidation
might be increased in uremia. METHODS: To address this hypothesis, we applied gas
chromatography-mass spectrometry and high performance liquid chromatography to
measure protein adducts formed in uremic plasma by reactions between carbonyl
compounds and protein amino groups: pentosidine derived from carbohydrate-derived
carbonyls, malondialdehyde (MDA)-lysine derived from lipid-derived carbonyls, and
CML originating possibly from both sources. RESULTS: All three adducts were
elevated in uremic plasma. Plasma CML levels were mainly (>95%) albumin bound.
Their levels were not correlated with fructoselysine levels and were similar in
diabetic and non-diabetic patients on hemodialysis, indicating that their
increase was not driven by glucose. Pentosidine and MDA-lysine were also
increased in plasma to the same extent in diabetic and non-diabetic hemodialysis
patients. Statistical analysis indicated that plasma levels of CML correlated
weakly (P < 0.05) with those of pentosidine and MDA-lysine, but that pentosidine
and MDA-lysine varied independently (P > 0.5). CONCLUSIONS: These data suggest
that the increased levels of AGEs in blood, and probably in tissues, reported in
uremia implicate a broad derangement in non-enzymatic biochemistry involving
alterations in autoxidation of both carbohydrates and lipids.
PMID- 9767547
TI - The multidimensional nature of renal disease: rates and associations of
albuminuria in an Australian Aboriginal community.
AB - BACKGROUND: An epidemic of end-stage renal disease (ESRD) is accompanying the
rising rates of hypertension, type 2 diabetes and cardiovascular disease among
Aborigines in the Northern Territory of Australia. Incidence rates are now 21
times those of nonAboriginal Australians and are doubling every four years. We
describe the rates and associations of renal disease in one remote community,
which has a current ESRD incidence of 2700 per million, and cardiovascular
mortality among the highest in Australia. METHODS: Between 1992 and 1995 a
community-wide screening program was conducted, in which the urinary
albumin/creatinine ratio (ACR) was used as the chief renal disease marker. More
than 90% of the population ages five and older participated. RESULTS: Albuminuria
was evident in early childhood and increased dramatically with age; 26% of adults
had microalbuminuria and 24% had overt albuminuria. All renal failure developed
out of a background of overt albuminuria. ACR was significantly correlated with
the presence of scabies at screening, with a history of poststreptococcal
glomerulonephritis, which is epidemic and endemic in the community, with
increasing body wt, blood pressure, glucose, insulin and lipid levels, and with
evidence of heavy drinking. ACR was also significantly and inversely correlated
with birth weight. As a result of its association with deteriorating hemodynamic
and metabolic profiles, increasing ACR was also correlated with increasing
cardiovascular risk score. Direct observations showed, and multivariate models
predicted, progressive amplification of ACR when multiple risk factors were
present simultaneously. Albuminuria also clustered in families. CONCLUSION: Renal
disease in this population is multifactorial, with risk factors related to whole
of-life nutrition, metabolic and hemodynamic profiles, infections, health
behaviors, and possibly a family predisposition. Its relationship to low birth
weight, and its associations with deteriorating metabolic and hemodynamic
profiles, suggest that renal disease is, in part, a component of Syndrome X,
which explains the simultaneous increase in metabolic, cardiovascular and renal
disease in Aboriginal people. The family clustering might have both environmental
and genetic causes, and is under further investigation. Most of the identified
risk factors arise out of poverty, disadvantage and accelerated lifestyle change,
and the current epidemic can be explained by the confluence of many risk factors
in the last few decades. The introduction of effective and sustained programs to
address social, economic and educational inequities in all Aboriginal
communities, and of screening and renal- and cardiovascular-protective treatment
programs for those already afflicted are matters of great urgency.
PMID- 9767548
TI - American Indian heritage and risk factors for renal injury.
AB - BACKGROUND: Little is known about the causes and consequences of renal disease
among American Indians in the Great Lakes region of the United States. METHODS:
We examined clinical correlates of albumin/creatinine ratios among 1368
participants in the three tribal communities of the Inter-Tribal Heart Project
using univariate and multivariate analysis. RESULTS: Compared to 1086
participants without albuminuria, the 240 with microalbuminuria (30 to 299 mg/g)
and the 42 with macroalbuminuria (>300 mg/g) were more likely to report a history
of a myocardial infarction (6.4%, 16.0%, and 23.8%, respectively, P < 0.001).
Similarly, compared to patients without albuminuria, those with microalbuminuria
and macroalbuminuria were more likely to report a history of stroke (2.3%, 8.4%
and 26.2%, respectively, P < 0.001). In a multiple linear regression model,
independent correlates of albumin excretion (P < 0.05) included: fasting blood
sugar, treated diabetes, treated hypertension, higher systolic blood pressure,
lower diastolic blood pressure, abnormal electrocardiogram, a history of stroke,
the degree of American Indian heritage, and lower household income. CONCLUSIONS:
Urinary albumin excretion is associated with cardiovascular disease outcomes and
risk factors among American Indians of the Great Lakes region. Both heredity and
socioeconomic status appear to play a role in the pathogenesis of renal injury in
this population.
PMID- 9767549
TI - Effects of ribavirin on hepatitis C-associated nephrotic syndrome in four liver
transplant recipients.
AB - BACKGROUND: Hepatitis C virus infection (HCV) is associated with a variety of
extrahepatic disorders such as membranoproliferative glomerulonephritis (MPGN),
which is generally due to cryoglobulinemia. After liver transplantation for HCV
cirrhosis, alpha-interferon treatment against the recurrence of HCV in the liver
graft is poorly effective and may induce intractable graft rejection. METHODS: We
describe the cases of four liver transplant recipients treated with ribavirin for
HCV-related glomerulopathy and nephrotic syndrome. RESULTS: The nephrotic
syndrome was attenuated or disappeared during ribavirin therapy, and patients
showed a marked decrease in proteinuria and an increase in albuminemia. The
syndrome relapsed in two patients when ribavirin therapy was stopped, and a
favorable response was again obtained in both cases when the treatment was
resumed. The main adverse effect of ribavirin was anemia in two patients with
renal impairment. No graft rejection occurred. CONCLUSIONS: These findings
suggest that continuous therapy with low doses of oral ribavirin may improve the
proteinuria of hepatitis C-related glomerulonephritis, at least in liver
transplant recipients.
PMID- 9767550
TI - Unfavorable course of minimal change nephrotic syndrome in children with
intrauterine growth retardation.
AB - BACKGROUND: Intrauterine growth retardation (IUGR) is associated with higher
morbidity and mortality not only in perinatal life but also in later life. The
purpose of our study was to determine whether IUGR has any effect on the course
of minimal change nephrotic syndrome (MCNS) in children. METHODS: Forty children
who were between 1 and 16 years old at the onset of MCNS, who have been followed
for at least three years and for whom we were able to obtain birth weights and
gestational ages, were included. The diagnosis of MCNS was predicted on the basis
of clinical and laboratory features, and in 11 children (27.5%) the diagnosis was
confirmed by renal biopsy. IUGR was defined as birth weight below the tenth
percentile for gestational age. RESULTS: Five children (12.5%) had signs of IUGR
at birth. In children with IUGR, we observed a higher mean number of relapses
(10.4 vs. 3.3, P < 0.001) and a higher incidence of steroid dependency (80% vs.
21%, P < 0.02) than in children without IUGR. Other differences between children
with and those without IUGR included more frequent treatment with cytotoxic
agents and cyclosporine, and a higher incidence of renal biopsy in children with
IUGR. CONCLUSION: Our study demonstrated an unfavorable course of MCNS in
children with IUGR. IUGR could therefore enable early identification of those
children who are at risk of becoming frequent relapsers and of developing steroid
dependency. This, however, should be confirmed in a larger number of patients.
PMID- 9767551
TI - Activation of both coagulation and fibrinolysis in childhood hemolytic uremic
syndrome.
AB - BACKGROUND: Thrombotic microangiopathy is the fundamental lesion in diarrhea
associated hemolytic uremic syndrome. The extent of the lesion in the renal
parenchyma determines the severity and outcome of the disorder, bilateral renal
cortical necrosis being the worst end of the spectrum. In the early years,
intravascular coagulation was considered the most important pathogenic mechanism.
Yet, individual coagulation factors were normal in the vast majority of patients
and therapy with anticoagulants did not alter the course. Recent studies indicate
that impaired fibrinolysis might be of importance. METHODS: We studied seven
variables of the coagulation pathway (PT, aPTT, fibrinogen, FVIII:c, von
Willebrand factor, thrombin-antithrombin complexes, prothrombin fragments 1+2)
and seven parameters of the fibrinolytic system (plasminogen, alpha2-antiplasmin,
C1-esterase inhibitor, tissue-type plasminogen activator, urokinase-type
plasminogen activator, plasminogen activator inhibitor type 1, D-dimer) in 24
pediatric patients with diarrhea-associated hemolytic uremic syndrome and in 15
children with acute renal failure not due to hemolytic uremic syndrome. Samples
were collected at diagnosis and every second day thereafter for a period of ten
days. Additional samples were collected from patients who underwent dialysis,
that is, before and after each session from those subjected to hemodialysis and
every day from those subjected to peritoneal dialysis. The obtained data were
compared with data from a control group consisting of healthy children. RESULTS:
Our data show four important features. (1) A significant increase in both
thrombin-antithrombin complexes (P < 0.005) and prothrombin fragments 1 + 2 (P <
0.001) is observed in hemolytic uremic patients as compared to patients with
acute renal failure of other causes. This finding is clearly indicative for an
activation of the coagulation pathway. (2) Patients with the hemolytic uremic
syndrome have significantly higher D-dimer levels, a sensitive marker of fibrin
specific fibrinolysis, as compared to patients with acute renal failure of other
causes (P < 0.005). (3) Levels of plasminogen activator inhibitor-1 (active
antigen as well as plasminogen activator inhibitor-1 activity) are not different
in both patient groups. In contrast, plasma levels of tissue-type plasminogen
activator and urokinase-type plasminogen activator are significantly higher in
the hemolytic uremic patients than in those with acute renal failure of other
causes (P < 0.01 and P < 0.05 respectively). (4) Hemodialysis leads to an
increase in tissue-type plasminogen activator antigen and a decrease of
plasminogen activator inhibitor-1 activity levels. CONCLUSIONS: Our data
demonstrate that in children with diarrhea-associated hemolytic uremic syndrome,
limited intravascular coagulation occurs, without evidence of impaired
fibrinolysis.
PMID- 9767553
TI - Role of cytokines in the response to erythropoietin in hemodialysis patients.
AB - BACKGROUND: Cytokines are regulatory factors of erythropoiesis, especially in
pathologic conditions. Even though a relevant role for a deranged cytokine
production in the pathogenesis of dialysis anemia has been suggested, no data are
available that analyze the role of cytokines in the key therapeutic issue of the
needs of erythropoietin. The aim of the present study in hemodialysis patients
was, therefore, to examine the relationship between the dose of recombinant human
erythropoietin (EPO) and the production of cytokines by peripheral blood
mononuclear cells (PBMC). METHODS: After the exclusion of subjects with major
active causes of EPO resistance, data from 34 hemodialysis patients were
available for analysis. Cytokine levels were measured in the supernatants of
stimulated [with bacterial lipopolysaccharide and interferon gamma (IFN-gamma)]
and unstimulated PBMC. Mean yearly values of hematocrit, hemoglobin, transferrin
saturation, ferritin, parathormone (PTH) and aluminum levels and EPO doses
(U/kg/week) were calculated. For analysis, the 34 patients were divided according
to their cutoff requirements for EPO: patients with requirements of EPO > or = 60
U/kg/week (group A1, 26 subjects) versus EPO < 60 U/kg/week (group B1, 8
subjects) and patients with requirements of EPO > or = 100 U/kg/week (group A2,
18 subjects) versus <100 U/kg/week (group B2, 16 subjects). RESULTS: A
significant direct correlation between interleukin-6 (IL-6) and tumor necrosis
factor alpha (TNF-a) production values and EPO doses was found (P = 0.039 and P =
0.02 respectively). On the other hand, there was a significantly negative
correlation between interleukin-12 (IL-12) production values and EPO doses (P =
0.029). Patients of groups A1 and A2 had spontaneously higher tumor necrosis
factor-alpha (TNF-alpha) and lower IL-12 and IFNgamma production compared to
patients from groups B1 and B2. CONCLUSIONS: Our data disclose a previously
undescribed pattern of cytokine alteration that is relevant to determine
increased needs of EPO in hemodialysis patients. The present results have
potential applicability in designing strategies to improve EPO resistance.
PMID- 9767552
TI - Detection of urinary tract infections by reduction of nitroblue tetrazolium.
AB - BACKGROUND: Nitroblue tetrazolium (NBT) reduction to formazan has been used as a
marker for nitric oxide synthase (NOS). Since inducible NOS activity is elevated
in urine from patients with urinary tract infections (UTIs), we investigated the
accuracy of NBT reduction as an early predictor of UTIs and quantified the
relationship between inducible NOS and NBT. METHODS: Urine samples from 434
patients were screened for the presence of UTIs with leukocyte-esterase and
nitrite dipsticks and with NBT reduction. The rapid screening results from each
test were compared to urine culture results. In addition, NBT reduction
parameters were measured in urine pellet at 595 nm after incubation with one of
four factors: NOS cofactors, NOS inhibitors, NADH, or superoxide
dismutase/catalase. RESULTS: As a urine screening test for UTIs, NBT reduction
was more sensitive with a higher negative predictive accuracy than the nitrite
dipstick. NBT reduction also was more specific with a higher positive predictive
accuracy and negative predictive accuracy than the leukocyte-esterase dipstick.
In infected urine pellet, both NADPH, a NOS cofactor, and NADH increased NBT
reduction. Superoxide dismutase/catalase decreased NBT reduction. CONCLUSIONS:
Although NOS may not be the only NBT reducing enzyme, rapid, visible reduction of
NBT is induced in urine from patients with UTIs.
PMID- 9767554
TI - Effects of estrogen replacement therapy on the lipoprotein profile in
postmenopausal women with ESRD.
AB - BACKGROUND: Patients with ESRD have excessive cardiovascular morbidity and
mortality. In postmenopausal women with normal renal function, estrogen
replacement therapy decreases cardiovascular mortality by 50%, in part because of
their beneficial effects on the lipoprotein profile. Because of similarities in
the lipoprotein profile between healthy, postmenopausal women, and women with
ESRD, we examined the effects of estrogen replacement on lipoproteins in 11
postmenopausal women with ESRD. METHODS: In a randomized, placebo-controlled
crossover study (8 week treatment arms) using 2 mg daily of oral, micronized
estradiol, 11 postmenopausal women with ESRD were treated. Neither baseline lipid
nor lipoprotein abnormalities were used as entry criteria for study
participation. RESULTS: Blood estradiol levels were 19 +/- 4 with placebo and 194
+/- 67 pg/ml (P = 0.024) with estradiol treatment. Total HDL cholesterol
concentrations increased from 52 +/- 19 mg/dl to 61 +/- 20 mg/dl (16%), with
placebo and estradiol treatments, respectively (P = 0.002). Apolipoprotein A1
increased by 24.6% (P = 0.0002) with estradiol intervention. HDL2 concentrations
were 19 +/- 13 with placebo and 24 +/- 16 with estradiol treatment (P = 0.046).
There were no differences in total or LDL cholesterol, other lipoprotein
fractions including Lp(a), and triglycerides with 2 mg daily estradiol treatment.
No significant side effects were observed. CONCLUSIONS: Therefore, using standard
dosage regimens for estrogen replacement therapy in postmenopausal women with
ESRD, HDL cholesterol is increased to an extent that would be expected to improve
their cardiovascular risk profile. Further studies are needed to assess whether
estrogen replacement therapy decreases the incidence or severity of
cardiovascular disease in ESRD patients to a similar degree compared with other
women.
PMID- 9767555
TI - Randomized comparison of triple therapy and antithymocyte globulin induction
treatment after simultaneous pancreas-kidney transplantation.
AB - BACKGROUND: The incidence of acute rejection is considered to be higher after
simultaneous pancreas-kidney (SPK) transplantation as compared to renal
transplant alone. Therefore, the majority of SPK transplant recipients commonly
receive a combination of cyclosporine (CsA) or tracolimus, and azathioprine or
mycophenolic mofetyl, corticosteroids and/or antilymphocyte preparations. This
study was designed to compare two immunosuppressive protocols for the prevention
of acute rejection in patients undergoing SPK transplantation. The primary end
point was the incidence of acute rejection during the first 12 months after
transplantation METHODS: Fifty patients with type-I insulin-dependent diabetes
and chronic renal failure were randomized to receive a triple drug
immunosuppressive regimen including CsA, azathioprine and corticosteroids (N =
25), or the quadruple sequential combination of rabbit antithymocyte globulin
(ATG) given for 10 days, azathioprine, corticosteroids and delayed CsA (N = 25).
Maintenance immunosuppression (CsA and azathioprine, without corticosteroids) was
similar in both arms. RESULTS: The average follow-up was 36 months in both groups
(range 9 to 60 months). No patient was excluded from the study. Although the
percentage of patients with adverse events was higher in the ATG group (80 vs.
40%, P < 0.01), none of them resulted in premature discontinuation of the drug.
Patients receiving ATG experienced a lower incidence (36% vs. 76%, P < 0.01) and
number (13 vs. 29, P < 0.05) of acute renal rejection episodes. However, no
difference was observed in patient, pancreas and kidney survival rates between
groups. No case of isolated pancreas rejection was observed. CONCLUSIONS: The
quadruple sequential combination ATG, azathioprine, corticosteroid and CsA
significantly reduced the one year incidence of acute renal rejection after SPK
transplantation, compared to a triple immunosuppressive regimen.
PMID- 9767556
TI - N epsilon-(carboxymethyl)lysine in blood from maintenance hemodialysis patients
may contribute to dialysis-related amyloidosis.
AB - BACKGROUND: Recent studies demonstrated not only that advanced glycation end
product could be found in amyloid tissue from patient with dialysis related
amyloidosis, but also that amyloid beta2-microglobulin was modified with
N(epsilon)-(carboxymethyl)lysine (CML). We wanted to determine if CML could be a
biomarker in these patients. METHODS: To raise polyclonal anti
carboxymethyllysine antibody, human serum albumin was carboxymethylated by
glyoxylic acid and was immunized to rabbits as antigen. Carboxymethyllysine
hemoglobin (CML-Hb) levels were measured by the dot blotting method using this
antibody. RESULTS: The levels of CML-Hb were 6.68 +/- 3.10 nmol CML/mg Hb in
nondiabetic hemodialysis patients (N = 70), 6.39 +/- 3.43 nmol CML/mg Hb in
diabetic hemodialysis patient (N = 21), and 3.13 +/- 0.88 nmol CML/mg Hb in 47
healthy volunteers. For clinical signs of dialysis-related amyloidosis, 70
nondiabetic hemodialysis patients were scored according Gejyo's criteria. The CML
Hb levels in patients with a high amyloid score as well as a low amyloid score
were significantly higher than in patients with negative amyloid score (8.89 +/-
3.53 nmol CMLmg Hb, 7.28 +/- 2.32 nmol CML/mg Hb vs. 5.11 +/- 2.09 nmol CML/mg
Hb, P < 0.001, P < 0.05). Furthermore, the CML-Hb levels correlated significantly
with serum values of the methylguanidine over creatinine ratio and hyaluronate.
CONCLUSIONS: We suggest that CML-Hb is increased in blood from patients on
maintenance hemodialysis and is thus a potential biomarker of oxidative damage in
these patients. Moreover, CML-modification of protein may play a pathogenic role
in the development of dialysis related amyloidosis.
PMID- 9767557
TI - Outbreak of sterile peritonitis among continuous cycling peritoneal dialysis
patients.
AB - BACKGROUND: Approximately 30,000 patients receive peritoneal dialysis in the
United States. In August 1996, several dialysis centers from different states
reported sterile peritonitis among CCPD patients using sterile peritoneal
dialysis solution (PDS) from a single manufacturer. The manufacturer recalled 53
lots of PDS that had passed established industry guidelines and Food and Drug
Administration (FDA) approved quality control tests [including endotoxin levels
<0.5 endotoxin units (EU)/ml], but had pre-sterilization bacterial colony counts
>1 cfu/ml. METHODS: At one outpatient dialysis center, Hospital of the University
of Pennsylvania (HUP), we conducted a retrospective cohort study of all CCPD
patients treated during July 15 to August 30, 1996. A case-patient was defined as
any HUP patient with culture-negative peritoneal fluid with a white blood cell
count >100/mm3, cloudy peritoneal fluid, and/or abdominal pain. PDS and tubing
were cultured for bacteria and assayed for endotoxin. RESULTS: Overall, 14 of 28
patients had sterile peritonitis. The only risk factor identified was exposure to
> or =1 lot of recalled PDS (14 of 22 vs. 0/6, P = 0.02); the more recalled lots
received, the higher the attack rate (P = 0.0001). Five of 47 PDS bags had
detectable endotoxin; recalled lots were more likely to have measurable endotoxin
than nonrecalled lots (5/19 vs. 0/17, P = 0.05). When case-patients resumed CCPD
using PDS from non-recalled lots, no further cases were reported. CONCLUSIONS:
Our results suggest that this outbreak was caused by intrinsic PDS contamination
with endotoxin. Pre-sterilization colony counts may be an important quality
control indicator for CCPD fluids in conjunction with endotoxin levels.
PMID- 9767558
TI - Estimation of peritoneal mass transport by three-pore model in children.
AB - BACKGROUND: Computerized modeling is increasingly used to optimize the efficacy
of peritoneal dialysis (PD). The Personal Dialysis Capacity (PDC) test is a new
tool to model PD efficacy based on the three-pore model of peritoneal mass
transport. We sought to evaluate (i) whether the PDC test is applicable to
children on chronic PD, and (ii) whether the physiological mass transport
coefficients defined in the three pore model are dependent on age or body size in
childhood. METHODS: A validation study was performed in 32 pediatric chronic PD
patients. Twenty tests were performed using a standard CAPD regimen, and 22 tests
using a simplified automated PD (APD) protocol. Test accuracy and precision were
evaluated by comparison of predicted with measured 24-hour dialysate clearances
of urea, creatinine, beta2-microglobulin and albumin and ultrafiltration rates.
Long-term reproducibility was assessed in 16 patients by repeated clearance
studies after a median time interval of 10 weeks. RESULTS: While daily clearances
of urea and creatinine were predicted with good precision and accuracy with both
test protocols (concordance correlation coefficients 0.90 to 0.98, mean
difference predicted-calculated -0.6 to +0.6 ml/min/1.73 m2), ultrafiltration
rates were predicted more closely by the APD (r = 0.97) than by the CAPD test
(0.80). Middle and large molecule clearances were predicted less precisely in
both test settings (r = 0.48 to 0.83). Re-test reproducibility was slightly lower
than the predictive precision observed in the original test (r = 0.80 to 0.91).
The calculated total peritoneal pore area increased in absolute terms, decreased
with body size when standardized to weight, and was independent of body size when
normalized to body surface area. The body size-normalized fluid reabsorption rate
was slightly increased in young infants compared to older children or adults.
CONCLUSIONS: The PDC test permits to model peritoneal solute and water transport
with remarkable precision in children of all age groups. While the peritoneal
pore area is a linear function of body surface area, fluid reabsorption appears
to be slightly increased in young infants.
PMID- 9767559
TI - Serum total homocysteine concentration before and after renal transplantation.
AB - BACKGROUND: Hyperhomocysteinemia is by now an established risk factor for the
development of atherosclerosis. Total homocysteine concentration (tHcy)
correlates inversely with glomerular filtration rate, and it is roughly three
times as high in hemodialysis patients as in healthy individuals. Therefore, tHcy
would be expected to fall markedly after successful renal transplantation. The
aim of the present study was to assess the changes in tHcy associated with renal
transplantation. METHODS: tHcy was analyzed in samples collected before renal
transplantation and at six months after transplantation in 55 stable patients,
all of whom were treated with cyclosporine (CS). tHcy was also analyzed in
samples from 55 controls characterized by markers of renal function that matched
those of the post-transplant state. RESULTS: At six months after transplantation,
tHcy was significantly decreased as compared with pretransplant tHcy (27.7 +/-
14.8 vs. 36.9 +/- 21.3 micromol/liter, P < 0.001). Post-transplant tHcy was
markedly higher than the tHcy of the control group (27.7 +/- 14.8 vs. 16.0 +/-
5.3 micromol/liter, P < 0.0001). The post-transplant change in tHcy ranged
widely, the average change being a reduction of 14%. Sixteen patients (29%)
actually manifested an increase in post-transplant tHcy. The post-transplant
changes in tHcy correlated inversely with pretransplant tHcy (r = -0.66, P <
0.0001) and directly with the changes in serum albumin concentrations (r = 0.35,
P < 0.05) and CS trough concentrations (r = 0.29, P < 0.05). A multivariate
analysis, including the post-transplant changes in serum concentrations of folate
and albumin as well as creatinine clearances explained 21% of the change in tHcy
(P < 0.05). After inclusion of the CS concentration, an independent predictor,
the model accounted for 28% of the post-transplant change in tHcy (P < 0.01).
CONCLUSION: The post-transplant reduction in tHcy was far smaller than expected
with respect to renal function, and the post-transplant changes in the major
biochemical determinants of tHcy contributed relatively little to explain the
change in tHcy. Thus, the results suggest the post-transplant introduction of one
or more factors that induce an increase in tHcy. Treatment with CS appears to be
such a factor.
PMID- 9767560
TI - Influence of hematocrit on the measurement of lipoproteins demonstrated by the
example of lipoprotein(a).
AB - BACKGROUND: The measurement of many parameters of human blood is usually
performed in plasma or serum. Since lipoproteins or apolipoproteins, for example,
are found almost exclusively in the plasma fraction after low-speed
centrifugation, these parameters can be expected to be distributed in a different
plasma volume depending on the hematocrit value. Therefore, the measured plasma
levels might be relatively too low or too high in comparison to the whole blood
concentrations in the case of abnormal hematocrit levels. The aim of our
experiments was to evaluate the extent of differences between whole blood and
plasma concentrations, taking as an example lipoprotein(a) [Lp(a)] in
hemodialysis patients with documented decreased hematocrit values. METHODS: Lp(a)
was measured in plasma as well as whole blood of 15 hemodialysis patients with
low hematocrit values (0.29 +/- 0.02) in comparison to 11 control subjects (0.45
+/- 0.04). RESULTS: Plasma concentrations were 27% higher in patients than in
controls (19.7 vs. 15.5 mg/dl). The relative difference was twice as high (59%)
when measured in whole blood (13.5 vs. 8.5 mg/dl). Similar relative differences
were observed when whole blood concentrations of 125 hemodialysis patients and
256 controls were calculated with the formula [Lp(a)plasma * (1-hematocrit)].
CONCLUSIONS: Our findings clearly demonstrate that hematocrit is a strong
confounding variable of lipoprotein measurement in epidemiological studies when
concentrations are measured in plasma, especially in cases of abnormal hematocrit
values. Furthermore, studies investigating the longitudinal changes of
lipoproteins should consider potential hematocrit changes.
PMID- 9767561
TI - Molecular pathogenesis of Bartter's and Gitelman's syndromes.
PMID- 9767562
TI - FadR, transcriptional co-ordination of metabolic expediency.
AB - FadR is an Escherichia coli transcriptional regulator that optimizes fatty acid
metabolism in response to exogenously added fatty acids. Many bacteria grow well
on long-chain fatty acids as sole carbon source, but at the expense of consuming
a useful structural material. Exogenous fatty acids are readily incorporated into
membrane phospholipids in place of the acyl chains synthesized by the organism,
and phospholipids composed of any of a large variety of exogenously derived acyl
chains make biologically functional membranes. It would be wasteful for bacteria
to degrade fatty acids to acetyl-CoA and then use this acetyl-CoA to synthesize
the same (or functionally equivalent) fatty acids for phospholipid synthesis.
This line of reasoning suggests that bacteria might shut down endogenous fatty
acid synthesis on the addition of long-chain fatty acids to the growth medium.
Moreover, this shutdown could be closely coupled to fatty acid degradation, such
that a bacterial cell would use a portion of the exogenous fatty acid for
phospholipid synthesis while degrading the remainder to acetyl-CoA. To a degree,
the bacterium could both have its cake (the acyl chains for phospholipid
synthesis) and eat it (to form acetyl-CoA). This scenario turns out to be true in
E. coli. The key player in this regulatory gambit is FadR, a transcription factor
that acts both as a repressor of the fatty acid degradation and as an activator
of fatty acid biosynthesis.
PMID- 9767563
TI - A glycyl radical solution: oxygen-dependent interconversion of pyruvate formate
lyase.
AB - Pyruvate formate-lyase (PFL) catalyses the non-oxidative dissimilation of
pyruvate to formate and acetyl-CoA using a radical-chemical mechanism. The enzyme
is enzymically interconverted between inactive and active forms, the active form
contains an organic free radical located on a glycyl residue in the C-terminal
portion of the polypeptide chain. Introduction of the radical into PFL only
occurs anaerobically, and the activating enzyme responsible is an iron-sulphur
protein that uses S-adenosyl methionine as cofactor and reduced flavodoxin as
reductant. As the radical form of PFL is inactivated by molecular oxygen it is
safeguarded during the transition to aerobiosis by conversion back to the radical
free, oxygen-stable form. This reaction is catalysed by the anaerobically induced
multimeric enzyme alcohol dehydrogenase. The genes encoding PFL and its
activating enzyme are adjacent on the chromosome but form discrete
transcriptional units. This genetic organization is highly conserved in many, but
not all, organisms that have PFL. Recent studies have shown that proteins
exhibiting significant similarity to PFL and its activating enzyme are relatively
widespread in facultative and obligate anaerobic eubacteria, as well as archaea.
The physiological function of many of these PFL-like enzymes remains to be
established. It is becoming increasingly apparent that glycyl radical enzymes are
more prevalent than previously surmised. They represent a class of enzymes with
unusual biochemistry and probably predate the appearance of molecular oxygen.
PMID- 9767564
TI - Archaea and the cell cycle.
AB - Sequence similarity data suggest that archaeal chromosome replication is
eukaryotic in character. Putative nucleoid-processing proteins display
similarities to both eukaryotic and bacterial counterparts, whereas cell division
may occur through a predominantly bacterial mechanism. Insights into the
organization of the archaeal cell cycle are therefore of interest, not only for
understanding archaeal biology, but also for investigating how components from
the other two domains interact and work in concert within the same cell; in
addition, archaea may have the potential to provide insights into eukaryotic
initiation of chromosome replication.
PMID- 9767565
TI - Morphological adaptation and inhibition of cell division during stationary phase
in Caulobacter crescentus.
AB - During exponential growth, each cell cycle of the alpha-purple bacterium
Caulobacter crescentus gives rise to two different cell types: a motile swarmer
cell and a sessile stalked cell. When cultures of C. crescentus are grown for
extended periods in complex (PYE) medium, cells undergo dramatic morphological
changes and display increased resistance to stress. After cultures enter
stationary phase, most cells are arrested at the predivisional stage. For the
first 6-8 days after inoculation, the colony-forming units (cfu) steadily
decrease from 10(9) cfu ml(-1) to a minimum of 3x10(7) cfu ml(-1) after which
cells gradually adopt an elongated helical morphology. For days 9-12, the cfu of
the culture increase and stabilize around 2 x 10(8) cfu ml(-1). The viable cells
have an elongated helical morphology with no constrictions and an average length
of 20 microm, which is 15-20 times longer than exponentially growing cells. The
level of the cell division initiation protein FtsZ decreases during the first
week in stationary phase and remains at a low constant level consistent with the
lack of cell division. When resuspended in fresh medium, the elongated cells
return to normal size and morphology within 12 h. Cells that have returned from
stationary phase proceed through the same developmental changes when they are
again grown for an extended period and have not acquired a heritable growth
advantage in stationary phase (GASP) compared with overnight cultures. We
conclude that the changes observed in prolonged cultures are the result of entry
into a new developmental pathway and are not due to mutation.
PMID- 9767566
TI - Identification of a novel gene involved in pilin glycosylation in Neisseria
meningitidis.
AB - The pili of Neisseria meningitidis are a key virulence factor, being major
adhesins of this capsulate organism that contribute to specificity for the human
host. Recently it has been reported that meningococcal pili are post
translationally modified by the addition of an O-linked trisaccharide, Gal (beta1
4) Gal (alpha1-3) 2,4-diacetimido-2,4,6-trideoxyhexose. Using a set of random
genomic sequences from N. meningitidis strain MC58, we have identified a novel
gene homologous to a family of glycosyltransferases. A plasmid clone containing
the gene was isolated from a genomic library of N. meningitidis strain MC58 and
its nucleotide sequence determined. The clone contained a complete copy of the
gene, here designated pglA (pilin glycosylation). Insertional mutations were
constructed in pglA in a range of meningococcal strains with well-defined
lipopolysaccharide (LPS) or pilin-linked glycan structures to determine whether
pglA had a role in the biosynthesis of these molecules. There was no alteration
in the phenotype of LPS from pglA mutant strains as judged by gel migration and
the binding of monoclonal antibodies. In contrast, decreased gel migration of the
pilin subunit molecules of pglA mutants was observed, which was similar to the
migration of pilins of galE mutants of same strains, supporting the notion that
pglA is a glycosyltransferase involved in the biosynthesis of the pilin-linked
trisaccharide structure. The pglA mutation, like the galE mutation reported
previously, had no effect on pilus-mediated adhesion to human epithelial or
endothelial cells. Pilin from pglA mutants were unable to bind to monospecific
antisera recognizing the Gal (beta1-4) Gal structure, suggesting that PglA is a
glycosyltransferase involved in the addition of galactose of the trisaccharide
substituent of pilin.
PMID- 9767567
TI - Regulation of Pseudomonas aeruginosa hemF and hemN by the dual action of the
redox response regulators Anr and Dnr.
AB - The oxidative decarboxylation of coproporphyrinogen III catalysed by an oxygen
dependent oxidase (HemF) and an oxygen-independent dehydrogenase (HemN) is one of
the key regulatory points of haem biosynthesis in Pseudomonas aeruginosa. To
investigate the oxygen-dependent regulation of hemF and hemN, the corresponding
genes were cloned from the P. aeruginosa chromosome. Recognition sequences for
the Fnr-type transcriptional regulator Anr were detected -44.5 bp from the 5' end
of the hemF mRNA transcript and at an optimal distance of -41.5 bp with respect
to the transcriptional start of hemN. An approximately 10-fold anaerobic
induction of hemN gene expression was mediated by the dual action of Anr and a
second Fnr-type regulator, Dnr. Regulation by both proteins required the Anr
recognition sequence. Surprisingly, aerobic expression of hemN was dependent only
on Anr. An anr mutant did not contain detectable amounts of hemN mRNA and
accumulated coproporphyrin III both aerobically and anaerobically, indicating the
importance of HemN for aerobic and anaerobic haem formation. Mutation of hemN and
hemF did not abolish aerobic or anaerobic growth, indicating the existence of an
additional HemN-type enzyme, which was termed HemZ. Expression of hemF was
induced approximately 20-fold during anaerobic growth and, as was found for hemN,
both Anr and Dnr were required for anaerobic induction. Paradoxically, oxygen is
necessary for HemF catalysis, suggesting the existence of an additional
physiological function for the P. aeruginosa HemF protein.
PMID- 9767568
TI - Site-directed mutagenesis and virulence assessment of the katG gene of
Mycobacterium intracellulare.
AB - Mycobacterial catalases have been suggested as acting as virulence factors by
protecting intracellular mycobacteria from reactive oxidative metabolites
produced by host phagocytes. Mycobacterium intracellulare, like many other
mycobacteria, produces two proteins with catalase activity: a heat-stable
catalase (KatE) and an inducible, heat-labile catalase peroxidase (KatG). The M.
intracellulare katG gene was cloned, and a plasmid derivative with a 4 bp
insertion in the katG coding sequence was constructed and used for site-directed
mutagenesis of M. intracellulare 1403 (ATCC 35761). The resulting katG mutant was
highly resistant to isoniazid (INH), showed an increased sensitivity to H2O2 and
had lost peroxidase and heat-sensitive catalase activity but retained heat-stable
catalase activity. The plasmid carrying the katG frameshift allele was also used
for mutagenesis of the mouse virulent M. intracellulare isolate D673. After
intravenous injection into BALB/c mice, D673 and the isogenic katG mutant showed
the same growth kinetics in the spleen, liver and lungs of the infected mice. Our
results demonstrate that the KatG catalase peroxidase mediates resistance to H2O2
and susceptibility to INH but is not an essential virulence factor for the
survival and growth of M. intracellulare in the mouse.
PMID- 9767569
TI - botR/A is a positive regulator of botulinum neurotoxin and associated non-toxin
protein genes in Clostridium botulinum A.
AB - The genes of the botulinum neurotoxin A (BoNT) complex are clustered in a locus
consisting of two divergent polycistronic operons, one containing the non-toxic,
non-haemagglutinin (NTNH) component and bontA genes, the other containing the
haemagglutinin (HA) component genes. The two operons are separated by a gene
(botR/A, previously called orf21) encoding a 21 kDa protein. A recombinant
Clostridium botulinum A strain that overexpresses botR/A was constructed by
electroporating strain 62 with the vector pAT19 containing botR/A under the
control of its own promoter. The transformed strain produced more BoNT/A and
associated non-toxic proteins (ANTPs) and the corresponding mRNAs than the non
transformed strain. Partial inhibition of botR/A by antisense mRNA resulted in
lower levels of BoNT/A, NTNH and HA70 and the levels of the corresponding mRNAs.
Gel mobility shift assays and immunoprecipitations showed that BotR/A bound to
the DNA promoter region upstream from the two BoNT/A complex operons. These
results show that botR/A activated transcription of the genes encoding BoNT/A and
ANTPs in C. botulinum A by interacting directly with the region promoter, and
that the homologous genes in C. botulinum B, C and D presumably have the same
function.
PMID- 9767570
TI - Probing the active site of mitogillin, a fungal ribotoxin.
AB - Fungal ribotoxins, such as mitogillin and the related Aspergillus toxins
restrictocin and alpha-sarcin, are highly specific ribonucleases, which
inactivate the ribosome enzymatically by cleaving the eukaryotic 28S RNA of the
large ribosomal subunit at a single phosphodiester bond. The site of cleavage
occurs between G4325 and A4326, which are present in a 14-base sequence (the
alpha-sarcin loop) conserved among the large subunit rRNAs of all living species.
The amino acid residues involved in the cytotoxic activities of mitogillin were
investigated by introducing point mutations using hydroxylamine into a
recombinant Met-mature mitogillin (mitogillin with a Met codon at the N-terminus
and no leader sequence) gene constructed from an Aspergillus fumigatus cDNA
clone. These constructs were cloned into a yeast expression vector under the
control of the GAL1 promoter and transformed into Saccharomyces cerevisiae. Upon
induction of mitogillin expression, surviving transformants revealed that
substitutions of certain amino acid residues on mitogillin abolished its
cytotoxicity. Non-toxic mutant genes were cloned into an Escherichia coli
expression vector, the proteins overexpressed and purified to homogeneity and
their activities examined by in vitro ribonucleolytic assays. These studies
identified the His-49Tyr, Glu-95Lys, Arg-120Lys and His-136Tyr mutations to have
a profound impact on the ribonucleolytic activities of mitogillin. We conclude
that these residues are key components of the active site contributing to the
catalytic activities of mitogillin.
PMID- 9767571
TI - Sequence and analysis of the 60 kb conjugative, bacteriocin-producing plasmid
pMRC01 from Lactococcus lactis DPC3147.
AB - The complete sequence of pMRC01, a large conjugative plasmid from Lactococcus
lactis ssp. lactis DPC3147, has been determined. Using a shotgun sequencing
approach, the 60,232 bp plasmid sequence was obtained by the assembly of 1056
underlying sequences (sevenfold average redundancy). Sixty-four open reading
frames (ORFs) were identified. Analysis of the gene organization of pMRC01
suggests that the plasmid can be divided into three functional domains, with each
approximately 20 kb region separated by insertion sequence (IS) elements. The
three regions are (i) the conjugative transfer region, including a 16-gene Tra
(transfer) operon; (ii) the bacteriocin production region, including an operon
responsible for the synthesis of the novel bacteriocin lacticin 3147; and (iii)
the phage resistance and plasmid replication region of the plasmid. The complete
sequence of pMRC01 provides important information about these industrially
relevant phenotypes and gives insight into the structure, function and evolution
of large gram-positive conjugative plasmids in general. The completely sequenced
pMRC01 plasmid should also provide a useful framework for the design of novel
plasmids to be incorporated into starter strain improvement programmes for the
dairy industry.
PMID- 9767572
TI - Negative regulation by RpoS: a case of sigma factor competition.
AB - A mutation in the Escherichia coli gene encoding the stationary phase-inducible
sigma factor (sigmaS, RpoS) not only abolishes transcription of some genes in
stationary phase, but also causes superinduction of other stationary phase
induced genes. We have examined this phenomenon of repression by sigmaS using as
a model system the divergently transcribed stationary phase-inducible genes, uspA
and uspB. uspA is transcribed by sigma70-programmed RNA polymerase and is
superinduced in an rpoS mutant, while uspB induction is sigmaS dependent. The
data suggest that the superinduction of uspA is caused by an increased amount of
sigma70 bound to RNA polymerase in the absence of the competing sigmaS.
Increasing the ability of sigma70 to compete against sigmaS by overproducing
sigma70 mimics the effect of an rpoS mutation by causing superinduction of
sigma70-dependent stationary phase-inducible genes (uspA and fadD), silencing of
sigmaS-dependent genes (uspB, bolAp1 and fadL) and inhibiting the development of
sigmaS-dependent phenotypes, such as hydrogen peroxide resistance in stationary
phase. In addition, overproduction of sigmaS markedly reduced stationary phase
expression of a sigma70-dependent promoter. Thus, we conclude that sigma factors
compete for a limiting amount of RNA polymerase during stationary phase. The
implications of this competition in the passive control of promoter activity is
discussed.
PMID- 9767573
TI - Expression of ptsG, the gene for the major glucose PTS transporter in Escherichia
coli, is repressed by Mlc and induced by growth on glucose.
AB - The gene for the glucose-specific transporter of the phosphotransferase system,
ptsG, is expressed from two promoters separated by 141 bp. The expression of the
major, shorter transcript is very strongly dependent upon cAMP/CAP. However,
unlike other CAP-activated genes, the expression of ptsG is higher in glucose
media than in glycerol, implying that ptsG is controlled by a glucose-inducible
regulator. A mutation in the mlc gene greatly enhances ptsG expression in a
glycerol-grown culture but has no effect on ptsG expression during growth on
glucose. The mlc gene encodes a transcriptional regulator that has been shown to
affect the expression of manXYZ and malT. ptsG mRNA levels are lower in the mlc
strain grown on glucose than in the same strain grown on glycerol. This is
presumably because of the greater catabolite repression in the glucose culture
than in glycerol. The final level of expression of ptsG in a mlc+ strain in
glucose is a compromise between specific induction by glucose and generalized
catabolite repression. The result is that ptsG expression is very similar in
glucose-grown cultures of wild-type and mlc strains. The Mlc protein binds to two
sites centred at -6 and -175 upstream of the major ptsG transcript. CAP binds at
40.5 compared with this site, typical of class II CAP-regulated promoters, and
the binding of CAP and Mlc is co-operative.
PMID- 9767574
TI - The Escherichia coli relBE genes belong to a new toxin-antitoxin gene family.
AB - Toxin-antitoxin systems are defined as a group of plasmid- and chromosome-encoded
loci that specify a cell toxin and a protein antitoxin. Plasmid-encoded toxin
antitoxin systems stabilize their replicons by killing plasmid-free cells. Here,
we show that the relBE genes of Escherichia coli K-12 have all the basic features
previously connected with toxin-antitoxin systems: (i) relE encodes a cytotoxin
lethal or inhibitory to host cells; (ii) relB encodes an antitoxin that prevents
the lethal action of the relE-encoded toxin; (iii) the relBE genes stabilize a
mini-R1 test plasmid; and (iv) the RelB antitoxin autoregulates the relBEF operon
at the level of transcription. Using database searching, we found relBE
homologues on the chromosomes of E. coli K-12, Haemophilus influenzae and Vibrio
cholerae. A fifth relBE homologue was identified on the enterotoxin encoding E.
coli plasmid P307. Indirect evidence suggests that the toxicity of RelE may be
related to the inhibition of protein synthesis. Based on these observations, we
propose a model that explains the delayed relaxed phenotype associated with
mutations in relB.
PMID- 9767575
TI - The Escherichia coli threonyl-tRNA synthetase gene contains a split ribosomal
binding site interrupted by a hairpin structure that is essential for
autoregulation.
AB - The expression of the gene encoding Escherichia coli threonyl-tRNA synthetase
(ThrRS) is negatively autoregulated at the translational level. ThrRS binds to
its own mRNA leader, which consists of four structural and functional domains:
the Shine-Dalgarno (SD) sequence and the initiation codon region (domain 1); two
upstream hairpins (domains 2 and 4) connected by a single-stranded region (domain
3). Using a combination of in vivo and in vitro approaches, we show here that the
ribosome binds to thrS mRNA at two non-contiguous sites: region -12 to +16
comprising the SD sequence and the AUG codon and, unexpectedly, an upstream
single-stranded sequence in domain 3. These two regions are brought into close
proximity by a 38-nucleotide-long hairpin structure (domain 2). This domain,
although adjacent to the 5' edge of the SD sequence, does not inhibit ribosome
binding as long as the single-stranded region of domain 3 is present. A stretch
of unpaired nucleotides in domain 3, but not a specific sequence, is required for
efficient translation. As the repressor and the ribosome bind to interspersed
domains, the competition between ThrRS and ribosome for thrS mRNA binding can be
explained by steric hindrance.
PMID- 9767576
TI - Transcription of rpoH, encoding the Escherichia coli heat-shock regulator
sigma32, is negatively controlled by the cAMP-CRP/CytR nucleoprotein complex.
AB - In Escherichia coli, the rpoH gene encoding the essential heat-shock regulator
sigma32, is expressed in a complex manner. Transcription occurs from four
promoters (P1, P3, P4 and P5) and is modulated by several factors including (i)
two sigma factors (sigma70 and sigmaE); (ii) the global regulator CRP; and (iii)
the DnaA protein. Here, a further dissection of the rpoH regulatory region has
revealed that an additional transcription control exists that appears to link
rpoH expression to nucleoside metabolism. The cAMP-CRP complex and the CytR anti
activator bind co-operatively to the promoter region forming a repression complex
that overlaps the sigmaE-dependent P3 promoter and the sigma70-dependent P4 and
P5 promoters. During steady-state growth conditions with glycerol as the carbon
and energy source, transcription from P3, P4 and P5 is reduced approximately
threefold by CytR, whereas transcription from the upstream promoter, P1, appears
to be unaffected. Furthermore, in strains that slightly overproduce CytR,
transcription from P3, P4 and P5 is reduced even further (approximately 10-fold),
and repression can be fully neutralized by the addition of the inducer cytidine
to the growth medium. In the induced state, P4 is the strongest promoter and,
together with P3 and P5, it is responsible for most rpoH transcription (65-70%).
At present, CytR has been shown to 'fine tune' transcription of two genes (rpoH
and ppiA) that are connected with protein-folding activities. These findings
suggest that additional assistance in protein folding is required under
conditions in which CytR is induced (i.e. in the presence of nucleosides).
PMID- 9767578
TI - Downregulation of Escherichia coli yfiD expression by FNR occupying a site at
93.5 involves the AR1-containing face of FNR.
AB - The promoter of the FNR-activated yfiD gene of Escherichia coli has an unusual
architecture because it contains two FNR sites, an arrangement usually associated
with FNR-mediated repression. Investigation of yfiD promoter derivatives with
altered FNR sites revealed that occupation of the far upstream FNR site (FNR II)
downregulated expression, despite the presence of a FNR dimer activating
expression from the promoter proximal site (FNR I). Transcript mapping by primer
extension, and mutagenesis of potential -10 elements, indicated that yfiD
expression is driven from a single FNR-dependent promoter with FNR sites at -40.5
(FNR I) and -93.5 (FNR II). However, yfiD mRNA is processed in stationary-phase
cultures independently of rne, rpoS, ihfA and fis to yield transcripts lacking 12
and 21 bases from their respective 5' ends. Single amino acid substitutions (G74-
>C, F92-->S, A95-->P, R184-->P, P188-->A or L193-->P) in the surface of FNR that
contains activating region 1 (AR1 contacts the alpha-subunit of RNA polymerase to
promote transcription activation) reduced the inhibitory effect of FNR at FNR II,
indicating that this region of the protein may have a role in repression as well
as activation. The FNR variant F92-->S was notable because, although it activated
transcription of yfiD (two FNR sites), it was unable to activate transcription
from model Class I and II promoters, which contain only a single FNR site.
PMID- 9767577
TI - A novel mechanism for upregulation of the Escherichia coli K-12 hmp
(flavohaemoglobin) gene by the 'NO releaser', S-nitrosoglutathione: nitrosation
of homocysteine and modulation of MetR binding to the glyA-hmp intergenic region.
AB - The flavohaemoglobin gene, hmp, of Escherichia coli is upregulated by nitric
oxide (NO) in a SoxRS-independent manner. We now show that hmp expression is also
upregulated by S-nitrosoglutathione (GSNO, widely used as an NO releaser) and
sodium nitroprusside (SNP, which is a NO+ donor). Elevated homocysteine (Hcy)
levels, achieved either by adding Hcy extracellularly or using metE mutants,
decreased hmp expression. Conversely, metC mutants (defective in Hcy synthesis)
had higher levels of hmp expression. Mutations in metR abolished hmp induction by
GSNO and SNP, and hmp expression became insensitive to Hcy. We propose that the
previously documented modulation by Hcy of MetR binding to the glyA-hmp
intergenic regulatory region regulates hmp transcription. Although two MetR
binding sites are present in this region, only the higher affinity site proximal
to hmp is required for hmp induction by GSNO and SNP. GSNO and SNP react with Hcy
in vitro under physiologically relevant conditions of pH and temperature
generating S-nitrosohomocysteine, although in the latter case this would be co
ordinated to the Fe in SNP as a stable species. The free S-nitrosocysteine
generated in the reaction with GSNO breaks down to release NO more readily than
via homolysis of GSNO. As GSNO and SNP upregulate hmp similarly, the NO released
in the former case on reaction with homocysteine cannot be involved in hmp
regulation.
PMID- 9767579
TI - The positive inside rule is not determined by the polarity of the delta psi
(transmembrane electrical potential)
PMID- 9767580
TI - Competence regulons, genomics and streptococci.
PMID- 9767581
TI - Non-specific, general and multiple stress resistance of growth-restricted
Bacillus subtilis cells by the expression of the sigmaB regulon.
AB - Bacillus subtilis cells respond almost immediately to different stress conditions
by increasing the production of general stress proteins (GSPs). The genes
encoding the majority of the GSPs that are induced by heat, ethanol, salt stress
or by starvation for glucose, oxygen or phosphate belong to the sigmaB-dependent
general stress regulon. Despite a good understanding of the complex regulation of
the activity of sigmaB and knowledge of a very large number of general stress
genes controlled by sigmaB, first insights into the physiological role of this
nonspecific stress response have been obtained only very recently. To explore the
physiological role of this reguIon, we and others identified sigmaB-dependent
general stress genes and compared the stress tolerance of wild-type cells with
mutants lacking sigmaB or general stress proteins. The proteins encoded by sigmaB
dependent general stress genes can be divided into at least five functional
groups that most probably provide growth-restricted B. subtilis cells with a
multiple stress resistance in anticipation of future stress. In particular, sigB
mutants are impaired in non-specific resistance to oxidative stress, which
requires the sigmaB-dependent dps gene encoding a DNA-protecting protein.
Protection against oxidative damage of membranes, proteins or DNA could be the
most essential component of sigmaB mediated general stress resistance in growth
arrested aerobic gram-positive bacteria. Other general stress genes have both a
sigmaB-dependent induction pathway and a second sigmaB-independent mechanism of
stress induction, thereby partially compensating for a sigmaB deficiency in a
sigB mutant. In contrast to sigB mutants, null mutations in genes encoding those
proteins, such as cIpP or cIpC, cause extreme sensitivity to salt or heat.
PMID- 9767582
TI - Timing, self-control and a sense of direction are the secrets of multicopy
plasmid stability.
AB - Multicopy plasmids of Escherichia coli are distributed randomly at cell division
and, as long as copy number remains high, plasmid-free cells arise only rarely.
Copy number variation is minimized by plasmid-encoded control circuits, and the
limited data available suggest that deviations are corrected efficiently under
most circumstances. However, plasmid multimers confuse control circuits, leading
to copy number depression. To make matters worse, multimers out-replicate
monomers and accumulate clonally within the culture, creating a subpopulation of
cells with a significantly increased rate of plasmid loss. Multimers of natural
multicopy plasmids, such as ColE1, are resolved to monomers by a site-specific
recombination system (Xer-cer) whose activity is limited to intramolecular
recombination. Recombination requires the heterodimeric XerCD recombinase plus
two accessory proteins (ArgR and PepA), which activate recombination and prevent
intermolecular events. Evidence is accumulating that Xer-cer recombination is
relatively slow, and there is a risk that cells might divide before multimer
resolution is complete. The Rcd transcript encoded within cer may solve this
problem by preventing the division of multimer-containing cells. Working in
concert, the triumvirate of copy number control, multimer resolution and cell
division control achieve an extremely high fidelity of plasmid maintenance.
PMID- 9767583
TI - A mechanism for simultaneous sensing of aspartate and maltose by the Tar
chemoreceptor of Escherichia coli.
AB - The Tar chemoreceptor of Escherichia coli exhibits partial sensory additivity.
Tar can mediate simultaneous responses to two disparate ligands, aspartate and
substrate-loaded maltose-binding protein (MBP). To investigate how one receptor
generates concurrent signals to two stimuli, ligand-binding asymmetry was imposed
on the rotationally symmetric Tar homodimer. Mutations causing specific defects
in aspartate or maltose chemotaxis were introduced pairwise into plasmid-borne
tar genes. The doubly mutated tar genes did not restore aspartate or maltose
chemotaxis in a strain containing a chromosomal deletion of tar (delta tar).
However, when Tar proteins with complementing sets of mutations were co-expressed
from compatible plasmids, the resulting heterodimeric receptors enabled delta tar
cells to respond to aspartate or maltose. The effect of one attractant on the
response to the other depended on the relative orientations of the functional
binding sites for aspartate and MBP. When the sites were in the 'same'
orientation, saturating levels of one attractant strongly inhibited chemotaxis to
the other. In the 'opposite' orientation, such inhibitory effects were
negligible. These data demonstrate that opposing subunits of Tar can transmit
signals to aspartate and maltose independently if the ligands are restricted to
the 'opposite' binding orientation. When aspartate and MBP bind in the 'same'
orientation, they compete for signalling through one subunit. In the wild-type
Tar dimer, aspartate and MBP can bind in either the 'same' or the 'opposite'
orientation, a freedom that can explain the partial additivity of the aspartate
and maltose responses that is seen with tar+ cells.
PMID- 9767584
TI - Functional conservation of the effector protein translocators PopB/YopB and
PopD/YopD of Pseudomonas aeruginosa and Yersinia pseudotuberculosis.
AB - Virulent Yersinia species cause systemic infections in rodents, and Y. pestis is
highly pathogenic for humans. Pseudomonas aeruginosa, on the other hand, is an
opportunistic pathogen, which normally infects only compromised individuals.
Surprisingly, these pathogens both encode highly related contact-dependent
secretion systems for the targeting of toxins into eukaryotic cells. In Yersinia,
YopB and YopD direct the translocation of the secreted Yop effectors across the
target cell membrane. In this study, we have analysed the function of the YopB
and YopD homologues, PopB and PopD, encoded by P. aeruginosa. Expression of the
pcrGVHpopBD operon in defined translocation-deficient mutants (yopB/yopD) of
Yersinia resulted in complete complementation of the cell contact-dependent, YopE
induced cytotoxicity of Y. pseudotuberculosis on HeLa cells. We demonstrated that
the complementation fully restored the ability of Y. pseudotuberculosis to
translocate the effector molecules YopE and YopH into the HeLa cells. Similar to
YopB, PopB induced a lytic effect on infected erythrocytes. The lytic activity
induced by PopB could be prevented if the erythrocytes were infected in the
presence of sugars larger than 3 nm in diameter, indicating that PopB induced a
pore of similar size compared with that induced by YopB. Our findings show that
the contact-dependent toxin-targeting mechanisms of Y. pseudotuberculosis and P.
aeruginosa are conserved at the molecular level and that the translocator
proteins are functionally interchangeable. Based on these similarities, we
suggest that the translocation of toxins such as ExoS, ExoT and ExoU by P.
aeruginosa across the eukaryotic cell membrane occurs via a pore induced by PopB.
PMID- 9767585
TI - The identification of Mycobacterium marinum genes differentially expressed in
macrophage phagosomes using promoter fusions to green fluorescent protein.
AB - Mycobacterium marinum, like Mycobacterium tuberculosis, is a slow-growing
pathogenic mycobacteria that is able to survive and replicate in macrophages.
Using the promoter-capture vector pFPV27, we have constructed a library of 200
1000 bp fragments of M. marinum genomic DNA inserted upstream of a promoterless
green fluorescent protein (GFP) gene. Only those plasmids that contain an active
promoter will express GFP. Macrophages were infected with this fusion library,
and phagosomes containing fluorescent bacteria were isolated. Promoter constructs
that were more active intracellularly were isolated with a fluorescence-activated
cell sorter, and inserts were partially sequenced. The promoter fusions expressed
intracellularly exhibited homology to mycobacterial genes encoding, among others,
membrane proteins and biosynthetic enzymes. Intracellular expression of GFP was 2
20 times that of the same clones grown in media. Several promoter constructs were
transformed into Mycobacterium smegmatis, Mycobacterium bovis BCG and
Mycobacterium tuberculosis. These constructs were positive for GFP expression in
all mycobacterial strains tested. Sorting fluorescent bacteria in phagosomes
circumvents the problem of isolating a single clone from macrophages, which may
contain a mixed bacterial population. This method has enabled us to isolate 12 M.
marinum clones that contain promoter constructs differentially expressed in the
macrophage.
PMID- 9767586
TI - Preprotein transfer to the Escherichia coli translocase requires the co-operative
binding of SecB and the signal sequence to SecA.
AB - In Escherichia coli, precursor proteins are targeted to the membrane-bound
translocase by the cytosolic chaperone SecB. SecB binds to the extreme carboxy
terminus of the SecA ATPase translocase subunit, and this interaction is promoted
by preproteins. The mutant SecB proteins, L75Q and E77K, which interfere with
preprotein translocation in vivo, are unable to stimulate in vitro translocation.
Both mutants bind proOmpA but fail to support the SecA-dependent membrane binding
of proOmpA because of a marked reduction in their binding affinities for SecA.
The stimulatory effect of preproteins on the interaction between SecB and SecA
exclusively involves the signal sequence domain of the preprotein, as it can be
mimicked by a synthetic signal peptide and is not observed with a mutant
preprotein (delta8proOmpA) bearing a non-functional signal sequence.
Delta8proOmpA is not translocated across wild-type membranes, but the
translocation defect is suppressed in inner membrane vesicles derived from a
prIA4 strain. SecB reduces the translocation of delta8proOmpA into these vesicles
and almost completely prevents translocation when, in addition, the SecB binding
site on SecA is removed. These data demonstrate that efficient targeting of
preproteins by SecB requires both a functional signal sequence and a SecB binding
domain on SecA. It is concluded that the SecB-SecA interaction is needed to
dissociate the mature preprotein domain from SecB and that binding of the signal
sequence domain to SecA is required to ensure efficient transfer of the
preprotein to the translocase.
PMID- 9767587
TI - Deletion analysis of MotA and MotB, components of the force-generating unit in
the flagellar motor of Salmonella.
AB - MotA and MotB are cytoplasmic membrane proteins that form the force-generating
unit of the flagellar motor in Salmonella typhimurium and many other bacteria.
Many missense mutations in both proteins are known to cause slow motor rotation
(slow-motile phenotype) or no rotation at all (non-motile or paralysed
phenotype). However, large stretches of sequence in the cytoplasmic regions of
MotA and in the periplasmic region of MotB have failed to yield these types of
mutations. In this study, we have investigated the effect of a series of 10-amino
acid deletions in these phenotypically silent regions. In the case of MotA, we
found that only the C-terminal 5 amino acids were completely dispensable; an
adjacent 10 amino acids were partially dispensable. In the cytoplasmic loop
region of MotA, deletions made the protein unstable. For MotB, we found that two
large segments of the periplasmic region were dispensable: the results with
individual deletions showed that the first consisted of six deletions between the
sole transmembrane span and the peptidoglycan binding motif, whereas the second
consisted of four deletions at the C-terminus. We also found that deletions in
the MotB cytoplasmic region at the N-terminus impaired motility but did not
abolish it. Further investigations in MotB were carried out by combining
dispensable deletion segments. The most extreme version of MotB that still
retained some degree of function lacked a total of 99 amino acids in the
periplasmic region, beginning immediately after the transmembrane span. These
results indicate that the deleted regions in the MotA cytoplasmic loop region are
essential for stability; they may or may not be directly involved in torque
generation. Part of the MotA C-terminal cytoplasmic region is not essential for
torque generation. MotB can be divided into three regions: an N-terminal region
of about 30 amino acids in the cytoplasm, a transmembrane span and about 260
amino acids in the periplasm, including a peptidoglycan binding motif. In the
periplasmic region, we suggest that the first of the two dispensable stretches in
MotB may comprise part of a linker between the transmembrane span of MotB and its
attachment point to the peptidoglycan layer, and that the length or specific
sequence of much of that linker sequence is not critical. About 40 residues at
the C-terminus are also unimportant.
PMID- 9767588
TI - Investigation of mycobacterial recA function: protein introns in the RecA of
pathogenic mycobacteria do not affect competency for homologous recombination.
AB - The recA locus of pathogenic mycobacteria differs from that of non-pathogenic
species in that it contains large intervening sequences termed protein introns or
inteins that are excised by an unusual protein-splicing reaction. In addition, a
high degree of illegitimate recombination has been observed in the pathogenic
Mycobacterium tuberculosis complex. Homologous recombination is the main
mechanism of integration of exogenous nucleic acids in M. smegmatis, a non
pathogenic mycobacterium species that carries an inteinless RecA and is amenable
to genetic manipulations. To investigate the function of recA in mycobacteria,
recA- strains of M. smegmatis were generated by allelic exchange techniques.
These strains are characterized (i) by increased sensitivity towards DNA-damaging
agents [ethylmethylsulphonate (EMS), mitomycin C, UV irradiation] and (ii) by the
inability to integrate nucleic acids by homologous recombination. Transformation
efficiencies using integrative or replicative vectors were not affected in recA-
mutants, indicating that in mycobacteria RecA does not affect plasmid uptake or
replication. Complementation of the recA- mutants with the recA from M.
tuberculosis restored resistance towards EMS, mitomycin C and UV irradiation.
Transformation of the complemented strains with suicide vectors targeting the
pyrF gene resulted in numerous allelic exchange mutants. From these data, we
conclude that the intein apparently does not interfere with RecA function, i.e.
with respect to competency for homologous recombination, the RecAs from
pathogenic and non-pathogenic mycobacteria are indistinguishable.
PMID- 9767589
TI - De novo fatty acid synthesis is required for establishment of cell type-specific
gene transcription during sporulation in Bacillus subtilis.
AB - A hallmark of sporulation of Bacillus subtilis is the formation of two distinct
cells by an asymmetric septum. The developmental programme of these two cells
involves the compartmentalized activities of sigmaE in the larger mother cell and
of sigmaF in the smaller prespore. A potential role of de novo lipid synthesis on
development was investigated by treating B. subtilis cells with cerulenin, a
specific inhibitor of fatty acid biosynthesis. These experiments demonstrated
that spore formation requires de novo fatty acid synthesis at the onset of
sporulation. The transcription of the sporulation genes that are induced before
the formation of two cell types or that are under the exclusive control of sigmaF
occurred in the absence of fatty acid synthesis, as monitored by spo-lacZ
fusions. However, expression of lacZ fusions to genes that required activation of
sigmaE for transcription was inhibited in the absence of fatty acid synthesis.
The block in sigmaE-directed gene expression in cerulenin-treated cells was
caused by an inability to process pro-sigmaE to its active form. Electron
microscopy revealed that these fatty acid-starved cells initiate abnormal polar
septation, suggesting that de novo fatty acid synthesis may be essential to
couple the activation of the mother cell transcription factors with the formation
of the differentiating cells.
PMID- 9767590
TI - Crl stimulates RpoS activity during stationary phase.
AB - RpoS, an alternative primary sigma factor, has been shown to be regulated at
multiple levels, including transcription, translation and protein stability.
Here, we present evidence that suggests that RpoS is regulated at yet another
level by the product of the crl gene. The crl gene was first thought to encode
the major curlin subunit of curli (curli are surface structures that are induced
by growth into stationary phase under conditions of low osmolarity and low
temperature). Later, it was determined that crl actually contributes in a
positive fashion to stimulate transcription of csgBA, the true locus encoding for
the major subunit of curli. RpoS is also required for normal stationary-phase
induction of csgBA. We found that lesions in crl, like lesions in rpoS, cause
increased transcription of ompF during stationary phase. Taken together, these
observations prompted us to analyse the effects of crl on an additional RpoS
regulated phenomenon. We found that a crl null allele influences expression of
RpoS-regulated genes in a fashion similar to an rpoS null allele. Genetic
evidence suggests that crl and rpoS function in a single pathway and that Crl
functions upstream, or in concert with, RpoS. Although the effects of Crl on RpoS
regulated genes is entirely dependent on the integrity of RpoS, the presence of a
crl null allele does not decrease the level of RpoS protein. Thus, we propose
that Crl stimulates the activity of the RpoS regulon by stimulating RpoS activity
during stationary phase.
PMID- 9767591
TI - An ExeAB complex in the type II secretion pathway of Aeromonas hydrophila: effect
of ATP-binding cassette mutations on complex formation and function.
AB - The energy-dependent secretion of aerolysin by Aeromonas hydrophila requires the
ExeA and ExeB proteins. An 85 kDa complex containing the two proteins was
identified in wild-type cells but not in cells producing either protein alone.
Radiolabelling followed by cross-linking, immunoprecipitation and then reduction
of the cross-links confirmed the presence of the two proteins in the same
complex. The complex could also be extracted intact from cell membranes with non
ionic detergents. A G229D substitution in the kinase-3a motif of ExeA strongly
reduced the level of aerolysin secretion, as did the replacement of the invariant
Lys of the kinase-1a motif (K56) with Arg. The G229D mutant contained very little
of the ExeA-ExeB complex, but overexpression of the mutant complex until wild
type levels were achieved allowed normal secretion. In contrast, the K56R
mutation had no effect on complex formation, but normal secretion levels occurred
only when there was a far greater amount of the complex present. These results
are consistent with a model in which binding of ATP by ExeA is required for ExeA
ExeB complex formation, while hydrolysis is required for its function in
secretion once established.
PMID- 9767592
TI - The pilH gene encodes an ABC transporter homologue required for type IV pilus
biogenesis and social gliding motility in Myxococcus xanthus.
AB - Type IV pilus genes have been shown to be required for social gliding motility in
Myxococcus xanthus. We report the discovery of four additional pil genes: pilD, a
homologue of type IV prepilin leader peptidases; and pilG, pilH and pilI, which
have no known homologues in other type IV pilus systems. pilH encodes an ATP
binding cassette (ABC) transporter homologue, the first such homologue to be
required for the biogenesis of any bacterial pilus type. pilG and pilI are co
transcribed with pilH and appear to be functionally related to pilH. Null mutants
of pilG, pilH and pilI all lack social motility, are deficient in pilus
production, have elevated sporulation efficiencies and display similar
developmental abnormalities. In addition, all three mutations reduced the amount
of PilA found in the supernatant after cells were sedimented from liquid culture.
We suggest that the products of these three genes form a single ABC exporter
complex, in which pilI is an integral membrane protein with membrane-spanning
domains, and pilG is an accessory factor. The complex may participate in pilus
assembly and/or the export of PilA pilin.
PMID- 9767593
TI - Identification of an amino-terminal substrate-binding domain in the Yersinia
tyrosine phosphatase that is required for efficient recognition of focal adhesion
targets.
AB - YopH is a protein tyrosine phosphatase (PTP) that is delivered into host
mammalian cells via a type III secretion pathway in pathogenic Yersinia species.
Although YopH is a highly active PTP, it preferentially targets a subset of
tyrosine-phosphorylated proteins in host cells, including p130Cas. Previous in
vitro studies have indicated that the carboxy-terminal PTP domain contributes
specificity to the interaction of YopH with substrates. However, it is not known
if the PTP domain is sufficient for substrate recognition by YopH. Here, we have
identified paxillin as an additional substrate of YopH in HeLa cells. In
addition, we have identified a domain in the amino-terminal region of YopH that
binds to both p130Cas and paxillin and is required for the efficient recognition
of substrates by the wild-type enzyme. This 'substrate-binding' domain exhibits a
ligand specificity that is similar to that of the Crk Src homology 2 (SH2)
domain, and it binds substrates directly in a phosphotyrosine-dependent manner.
The substrate-binding domain of YopH may represent a novel type of protein
protein interaction module, as it lacks significant sequence similarity with any
known SH2 or phosphotyrosine-binding (PTB) domain.
PMID- 9767594
TI - Toxin binding site of the diphtheria toxin receptor: loss and gain of diphtheria
toxin binding of monkey and mouse heparin-binding, epidermal growth factor-like
growth factor precursors by reciprocal site-directed mutagenesis.
AB - The transmembrane precursor of the monkey (Mk) heparin-binding, epidermal growth
factor-like growth factor (proHB-EGF) functions as a diphtheria toxin (DT)
receptor, whereas the mouse (Ms) precursor does not. Previously, using chimeric
Ms/Mk precursors, we have shown that DT resistance of cells bearing Ms proHB-EGF
may be accounted for by several amino acid substitutions between residues 122 and
148 within the EGF-like domain and that Glu-141 is an important amino acid
residue for DT binding. In this study, reciprocal site-directed mutagenesis was
performed on the major non-conserved residues in the region of 122-148, alone or
in combination, between Mk and Ms precursors to identify more precisely which
amino acid residues are important for DT binding. Two approaches were used. The
first, more traditional approach was to destroy DT sensitivity and binding of Mk
proHB-EGF by substitution(s) with the corresponding Ms residue(s). From the
single mutations, the greatest loss of DT sensitivity was observed with Mk/Glu
141His (approximately 4000-fold) and the next greatest with Mk/Ile-133Lys
(approximately fourfold). The double mutations Mk/Leu-127Phe/Glu-141His, Mk/Ile
133Lys/Glu-141His and Mk/His-135Leu/Glu-141His resulted in complete toxin
resistance (> 100000-fold). The second approach, both novel and complementary,
was to gain DT binding and sensitivity of Ms proHB-EGF by substitution(s) with
the corresponding Mk residue(s). Surprisingly, the single mutation Ms/His-141Glu
resulted in the gain of moderate DT sensitivity (> 260-fold). The double mutation
Ms/Lys-133Ile/His-141Glu and the triple mutation Ms/Lys-133Ile/Leu-135His/His
141Glu resulted in a progressive gain in toxin sensitivity (> 4700-fold and
>16000-fold respectively) and affinity. This triple mutant cell line is
essentially as sensitive (IC50 = 3.1 ng ml(-1)) as the highly toxin-sensitive
monkey Vero cell line (IC50 = 4 ng ml(-1)), indicating that these three Mk
residues enable the Ms proHB-EGF to act as a fully functional DT receptor. Taken
together, these results indicate that Glu-141 plays the most critical role in DT
binding and sensitivity and that two additional amino acid residues, Ile-133 and
His-135, also play significant roles.
PMID- 9767595
TI - Penicillin tolerance genes of Streptococcus pneumoniae: the ABC-type manganese
permease complex Psa.
AB - Downregulation of the major autolysin in Streptococcus pneumoniae leads to
penicillin tolerance, a feature that is characterized by the ability to survive
but not grow in the presence of antibiotic. Screening a library of mutants in
pneumococcal surface proteins for the ability to survive 10x minimum inhibitory
concentration (MIC) of penicillin revealed over 10 candidate tolerance genes. One
such mutant contained an insertion in the known gene psaA, which is part of the
psa locus. This locus encodes an ABC-type Mn permease complex. Sequence analysis
of adjacent DNA extended the known genetic organization of the locus to include
two new open reading frames (ORFs), psaB, which encodes an ATP-binding protein,
and psaC, which encodes a hydrophobic transmembrane protein. Mutagenesis of psaB,
psaC, psaA and downstream psaD resulted in penicillin tolerance. Defective
adhesion and reduced transformation efficiency, as reported previously for a psaA
mutant, were phenotypes shared by psaB-, psaC- and psaD- knockout mutants.
Western blot analysis demonstrated that the set of mutants expressed RecA, but
none of them showed translation of the autolysin gene, which is located
downstream of recA. The addition of manganese (Mn) failed to correct the abnormal
physiology. These results suggest that this ABC-type Mn permease complex has a
pleiotropic effect on pneumococcal physiology including adherence and autolysis.
These are the first genes suggested as being involved in triggering autolysin.
The results raise the possibility that loss of function of PsaA, by vaccine
induced antibody for instance, may promote penicillin tolerance.
PMID- 9767596
TI - Sphingomyelin, glycosphingolipids and ceramide signalling in cells exposed to P
fimbriated Escherichia coli.
AB - Uropathogenic Escherichia coli attach to epithelial cells through P fimbriae that
bind Galalpha1-4Galbeta-oligosaccharide sequences in cell surface
glycosphingolipids. The binding of P-fimbriated E. coli to uroepithelial cells
causes the release of ceramide, activation of the ceramide signalling pathway and
a cytokine response in the epithelial cells. The present study examined the
molecular source of ceramide in human kidney A498 cells exposed to P-fimbriated
E. coli. Agonists such as TNF-alpha and IL-1beta released ceramide from
sphingomyelin by the activation of endogenous sphingomyelinases and hydrolysis of
sphingomyelin, and triggered an IL-6 response. P-fimbriated E. coli caused a
slight increase in endogenous sphingomyelinase activity, but there was no
associated sphingomyelin hydrolysis. Instead, the concentration of galactose
containing glycolipids decreased. We propose that P-fimbriated E. coli differ
from other activators of the ceramide pathway, in that release of ceramide is
from receptor glycolipids and not from sphingomyelin. Receptor breakdown may be
an efficient host defence strategy, as it reduces the concentration of cell
surface receptors, releases soluble receptor analogues and activates an
inflammatory response.
PMID- 9767597
TI - Yeast gene YRR1, which is required for resistance to 4-nitroquinoline N-oxide,
mediates transcriptional activation of the multidrug resistance transporter gene
SNQ2.
AB - We have cloned and characterized a Saccharomyces cerevisiae gene YRR1 that is
important for resistance to the mutagen 4-nitroquinoline N-oxide (4-NQO). The
wild-type YRR1 gene encodes a protein that contains a Zn(II)2Cys6-type zinc
finger motif. Disruption of the YRR1 gene leads to hypersensitivity to 4-NQO. A
dominant mutation (YRR1-1) that confers strong resistance to 4-NQO has been
identified. Epistasis analysis demonstrated that 4-NQO resistances mediated by
the YRR1 and YRR1-1 alleles require the presence of the SNQ2 gene that encodes a
multidrug resistance ATP binding cassette superfamily protein responsible for 4
NQO export. Northern blot analysis of SNQ2 mRNA levels indicated that Yrr1p is
involved in basal and drug-induced transcriptional activation of SNQ2, whereas
Pdr1p/Pdr3p transcription factors are mainly involved in basal SNQ2 expression.
In the YRR1-1 mutant, the level of SNQ2 mRNA is constitutively elevated. These
results establish that Yrr1p is important for 4-NQO resistance by mediating
transcriptional activation of the SNQ2 gene in response to the stress imposed by
4-NQO. The gain-of-function mutation of Yrr1-1p was attributable to the
duplication of a 12-amino-acid sequence generated near the carboxy terminus.
PMID- 9767598
TI - Essential monomer-monomer contacts define the minimal length for the N-terminus
of RecA protein.
PMID- 9767599
TI - Widespread production of AS-48-like bacteriocins in strains of Enterococcus
faecalis?
PMID- 9767600
TI - Identification, characterization and expression of Toxocara canis nematode
polyprotein allergen TBA-1.
AB - We have cloned the cDNA of TBA-1, the Nematode polyprotein allergen (NPA) of
Toxocara canis and found it to be most similar to ABA-1, the Ascaris NPA, on the
basis of amino acid sequence. We could study the antigenic properties of an E
coli synthesized fusion protein prepared with the cloned gene since no
glycosylation site was expected from the deduced amino acid sequence. Although no
IgE responses to TBA-1 were detected, recombinant TBA-1 was differently
recognized by serum IgG antibodies when the recombinant TBA-1 was directly
adsorbed vs when immobilized via a streptavidin linkage on polystyrene microtitre
wells. One group of sera recognized TBA-1 directly immobilized while the second
only recognized TBA-1 immobilized via streptavidin linkage. The former were from
rodents immunized with a Toxocara sp. adult worm extract while the latter were
obtained from rodents infected with T. canis larva or immunized with a Anisakis
simplex L3 larval extract. These observations suggest that the two in vivo forms
of TBA-1 are expressed, but during different stages of the parasite's life cycle.
PMID- 9767601
TI - Murine immune responses to Schistosoma haematobium and the vaccine candidate
rSh28GST.
AB - Longitudinal studies of Schistosoma haematobium infection in CBA mice revealed a
progressive down-regulation of cellular immune responses, as measured by
mitogenic and antigenic stimulation of in vitro lymphocyte cultures. Antigen
stimulated production of the Th1 cytokine IFN-gamma by splenocytes increased
progressively up to 14 weeks post infection, (four weeks after the onset of
parasite egg production), before declining swiftly. Levels of the Th2 cytokine IL
4 in the same cultures remained low until 14 weeks, after which they rose rapidly
as IFN-gamma declined. High levels of IL-10 coincided with the peak in IFN-gamma
production, suggesting a non Th2-restricted role for this cytokine. Both total
and antigen-specific immunoglobulin production confirmed parasite egg deposition
as being a major stimulus for host humoral responses. The S. haematobium
infection failed to elicit detectable T cell responses to the antifecundity
vaccine candidate rSh28GST. However, low levels of antibody were detectable in
infected mouse serum and strong IgG and IgA production was induced by vaccination
with rSh28GST plus adjuvant.
PMID- 9767602
TI - Serum concentrations of sICAM-1, sE-, sP- and sL-selectins in patients with
Schistosoma mansoni infection and association with disease severity.
AB - Increased serum concentrations of soluble intercellular adhesion molecule-1
(sICAM-1, CD54) and of soluble E- (CD62E), but not soluble P- (CD62P) and L-
(CD62 L) selectins, were detected in Malagasy patients living in an hyperendemic
focus of Schistosoma mansoni. Levels of sICAM-1 remained elevated for several
months after treatment with praziquantel. Serum levels of ICAM-1, but not of
other markers, were significantly correlated with the disease severity, as
indicated by ultrasonographical data, and with some circulating fibrosis markers
(at least hyaluronic acid). sICAM-1 level may reflect endothelial inflammatory
reactions, probably harmful, in the liver and may be useful for monitoring
morbidity evolution in schistosomiasis mansoni.
PMID- 9767603
TI - Immunological properties of recombinant proteins of the transmission blocking
vaccine candidate, Pfs48/45, of the human malaria parasite Plasmodium falciparum
produced in Escherichia coli.
AB - A precondition for the development of a transmission blocking vaccine based on
the sexual stage-specific surface antigen Pfs48/45 of Plasmodium falciparum is
its heterologous synthesis in a native state. Here we describe the production of
recombinant Pfs48/45 in Escherichia coli. Two recombinant proteins, of which one
is a glutathione-S-transferase fusion protein, were produced. Enzyme-linked
immunosorbent assays showed that at least a subfraction of the recombinant
proteins had a conformation capable of binding transmission blocking monoclonal
antibodies. However, despite the fact that both proteins were very immunogenic,
they did not induce transmission blocking immunity in mice or rabbits.
Immunological studies with congenic mouse strains demonstrated that immune
responses could be boosted with gametocyte extracts and were not restricted to a
particular class II major histocompatibility complex haplotype.
PMID- 9767604
TI - IgG subclass recognition of Loa loa antigens and their correlation with clinical
status in individuals from Gabon.
AB - In endemic areas for Loa loa, a significant percentage of actively infected
individuals have no circulating microfilariae, an observation which implies the
existence of a stage-specific immune response. In an attempt to define the
immunological basis of the amicrofilaraemic state, the reactivity of antigens
from adult, microfilariae and infective larvae of L. loa was examined by Western
blotting with individual serum samples from four clinically defined groups (high
microfilaraemic, low microfilaraemic, amicrofilaraemic and endemic controls)
using IgG subclass-specific reagents and IgE. In the adult parasite, a complex of
antigens at 28-31 kDa was exclusively recognized by IgG1 from amicrofilaraemic
individuals and, to a lesser extent, by IgG1 from endemic controls. However, this
complex of antigens was recognized by IgG4 antibodies in serum samples from all
individuals, including microfilaraemics. A microfilarial antigen of 21 kDa was
recognized by IgG1 antibodies present in serum from amicrofilaraemic, endemic
control and low microfilaraemic individuals. Persons with high levels of
microfilariae did not recognise this antigen. In both the L3 and the
microfilariae, a ladder antigen with increments of 15 kDa was the main target of
IgG4 antibodies in amicrofilaraemic and microfilaraemic individuals. IgE
antibodies recognized more antigens in the microfilarial stage than in the adult
of L3. These results suggest that immunological differences between clinically
defined groups are associated with the recognition of different antigens or
epitopes.
PMID- 9767605
TI - Nitric oxide production in vervet monkeys (Cercopithecus aethiops) infected with
Trypanosoma brucei.
AB - A retrospective study of nitrate concentration in serum and cerebrospinal fluid
(CSF) from vervet monkeys (Cercopithecus aethiops) infected with Trypanosoma
brucei was undertaken. Serum nitrate was significantly elevated in parasitaemic
animals. CSF nitrate detection correlated with the presence of parasites in the
CNS. The results provide evidence for the production of nitric oxide (NO) in
response to infection in a primate model of human African trypanosomiasis and
provide the basis for the use of such a model in studies of the
immunopathological effects of NO in human trypanosomiasis.
PMID- 9767606
TI - Fc-binding molecules specific for human IgG1 and IgG3 are present in Echinococcus
granulosus protoscoleces.
AB - In this work we describe the presence of Fc-binding activity on the suckers and
tegument of E. granulosus protoscoleces. A fraction (PSA-Fc+) from protoscolex
somatic antigens was isolated by affinity chromatography on human Fc-gamma1
Sepharose. Analysis by SDS-PAGE of PSA-Fc+ showed that it contained two major
components. Using mouse F(ab')2-human Fc chimaeric monoclonal antibodies we
verified that PSA-Fc+ bound mainly to human Fc-gamma1 and Fc-gamma3 isotypes. In
addition, one of the components of PSA-Fc+ showed proteolytic activity. Both, Fc
binding and proteolytic activities localized on the protoscolex surface, may play
a relevant role in the host-parasite interaction.
PMID- 9767607
TI - Microbicidal activity of eosinophils is associated with activation of the
arginine-NO pathway.
AB - In order to investigate the ability of rat peritoneal eosinophils to produce
nitric oxide (NO) induced by cytokines in vitro, these cells were activated with
several cytokines (IL-5, IL-8, Rantes, TNF-alpha, IFN-gamma) in association or
not with LPS. Under these conditions, we were able to detect nitrite in the
incubation medium when the eosinophils were stimulated with IFN-gamma or IL-8 in
the presence of LPS. LPS alone also induced nitrite production. Significant
levels of nitrite in the medium were already present after 12 h of stimulation
and increased steadily within the next 48 h. Regarding NO synthase, its highest
activity was achieved at 12 h after IFN-gamma/LPS stimulation. After this peak,
the enzymatic activity reduced gradually to control levels 48 h after the
stimulation. The simultaneous addition of the NO synthase inhibitor L-NIO (100
microM) to the eosinophil suspension blocked nitrite production and NO synthase
activity. On the other hand, neither IL-5, Rantes nor TNF-alpha were able to
induce the release of nitrite in the presence or absence of LPS. To evaluate the
microbicidal effect of these cells against the Leishmania parasite, eosinophils
were infected with Leishmania major. It was observed that these cells were able
to produce nitrite and to kill the parasite after activation with LPS/IFN-gamma.
Moreover, L-NIO blocked this leishmanicidal activity and the nitrite production.
Our results suggest that activated eosinophils release NO which is involved in
their microbicidal activity against Leishmania major.
PMID- 9767608
TI - Intranasal immunization with yeast-expressed 19 kD carboxyl-terminal fragment of
Plasmodium yoelii merozoite surface protein-1 (yMSP119) induces protective
immunity to blood stage malaria infection in mice.
AB - Variable protection against malaria blood-stage infection has been demonstrated
in mice following parenteral immunization with the highly conserved 19 kD
carboxylterminal fragment of the merozoite surface protein-1 (MSP119) using
CFA/IFA and other adjuvants. Here we show that intranasal immunization of BALB/C
mice with yeast expressed Plasmodium yoelii MSP119 plus a mixture of native and
recombinant cholera toxin B subunit, could induce serum MSP119-specific
antibodies at titres ranging from 20 000 to 2 560 000. The Ig subclass responses
were predominantly G1 and G2b. Intranasal immunization led to protection
following challenge (peak parasitaemia < 1%) in mice with the highest MSP119
specific titre (>/= 640 000). In two of the three protected mice, a peak
parasitaemia of 0.1%-1% was followed by a boost of the antibody response whereas
one of the three protected mice did not boost its antibody response after a peak
parasitaemia of 0.02%. In unprotected mice, antibody levels rose, then fell,
following the detection of parasites in the peripheral blood. CD4+ T cell
depletion abrogated the ability of the mice to boost their antibody response
following challenge. These data demonstrate the potential for intranasal
immunization with MSP119 to protect against malaria.
PMID- 9767609
TI - Trypanosoma congolense infection of trypanotolerant N'Dama (Bos taurus) cattle is
associated with decreased secretion of nitric oxide by interferon-gamma-activated
monocytes and increased transcription of interleukin-10.
AB - The mechanisms whereby trypanotolerant N'Dama cattle control infection with
Trypanosoma congolense are unknown. Previous studies have suggested that the
monocytes of N'Dama cattle are more highly activated during infection than those
of trypanosusceptible Boran cattle. However, we have recently reported that the
monocytes of Boran cattle have a reduced capacity to secrete nitric oxide during
trypanosome infection. We therefore evaluated the production of nitric oxide by
monocytes of trypanotolerant N'Dama cattle infected with T. congolense in
response to interferon-gamma, bacterial lipopolysaccharide or trypanosome
antigens. Interferon-gamma-induced nitric oxide production was decreased between
days 25 and 76 of infection, while lipopolysaccharide-induced secretion of nitric
oxide was increased at days 13 and again at day 76 post-infection. Trypanosome
antigens did not elicit nitric oxide production. Analysis of interleukin-10 mRNA
transcription in peripheral blood leucocytes revealed an increase at time points
that coincided with decreased interferon-gamma-induced nitric oxide synthesis. In
contrast, interferon-gamma mRNA expression was not changed during infection while
tumour necrosis factor-alpha was slightly reduced at day 32 post-infection.
Recombinant interleukin-10 suppressed interferon-gamma-induced nitric oxide and
tumour necrosis factor-alpha secretion, but not lipopolysaccharide-induced nitric
oxide secretion in cultures of peripheral blood mononuclear cells and monocytes
of uninfected cattle. These results suggest that the nitric oxide response of
monocytes to IFN-gamma but not lipopolysaccharide, is suppressed during
infection. The kinetics of the upregulation of interleukin-10 and its biological
activity indicate a possible association with the depression of nitric oxide
production and control of tumour necrosis factor-alpha.
PMID- 9767610
TI - T cell responses in coinfection with Onchocerca volvulus and the human
immunodeficiency virus type 1.
AB - Onchocerca volvulus and the human immunodeficiency virus (HIV) are two
immunocompromising infectious agents of major public health concern in Uganda. To
examine the effect of coinfection with O. volvulus and HIV on cellular immune
responses, lymphocyte proliferative responses and cytokine production of
peripheral blood mononuclear cells (PBMC) from persons infected with O. volvulus
with and without HIV type 1 infection were compared. Proliferation of PBMC to PHA
and tuberculin (PPD) in coinfection was less (P = 0.08, P < 0.01) than in O.
volvulus infection. O. volvulus extract stimulated lymphocyte proliferation in
microfilaria-negative and HIV-negative O. volvulus infection while only an
inconspicuous response was observed in microfilaria-negative coinfection. After
stimulation of PBMC with PPD, the production of interferon-gamma (IFN-gamma),
interleukin (IL)-4 and IL-5-demonstrated in O. volvulus infection-were reduced in
coinfection with HIV (P < 0.01). While both groups failed to produce IFN-gamma in
response to O. volvulus extract, only O. volvulus infected persons generated
pronounced IL-5 and low IL-4 levels (0.01 > P = 0.02). The cellular immune
responses in coinfection suggested an HIV-related lack of specific reactivity to
O. volvulus antigen and impairment of IL-4 and IL-5 production in addition to the
lack of IFN-gamma response on antigenic stimulation.
PMID- 9767611
TI - Amelioration of virulent Babesia bovis infection in calves by administration of
the nitric oxide synthase inhibitor aminoguanidine.
AB - Calves undergoing initial infection with a virulent strain of the haemoprotozoan
parasite Babesia bovis were treated with aminoguanidine (AG), an inhibitor of the
inducible form of nitric oxide synthase (iNOS). The mean maximum parasitaemia of
the AG treated calves was significantly lower than that of the control cattle. In
addition, the febrile response and decrease in packed cell volume (PCV) observed
during acute infection were significantly ameliorated in the AG treated cattle
relative to the controls. However, AG had no effect on the multiplication of B.
bovis in the microaerophilous stationary-phase (MASP) in-vitro culture system.
These results provide evidence of a role for nitric oxide (NO) produced in
response to acute infection in the pathology of bovine babesiosis.
PMID- 9767613
TI - Non-surgical therapy for patients with advanced non-small cell lung cancer.
AB - Advanced non-small cell lung cancer (NSCLC) denotes those of TNM stage III and
IV. NSCLC has its specific characteristics in respect of oncological behaviour,
molecular biology, sensitivity to chemotherapy (CT) and radiotherapy (RT), and
requires different therapeutic strategies in comparison with small cell lung
cancer. The therapies include: (1) surgery in combination with new effective
drugs is resulted in improved RR from 15% a decade ago to 40-60% today. Cisplatin
(C-DDP) is the most attractive drug in the treatment of NSCLC, in lengthening the
life-span of Stage IV NSCLC patients and as an indispensable sensitizer in RT.
Taxinol, Gemcitabine (GEM), Navelbine (NVB), Edatrexate (ETX), CPT-11 and high
dose Epirubicin (EPI HD) are recommended as new effective drugs. Response rates
recently reported for the combination CT with the drugs mentioned above for NSCLC
are from 30-65%, and with 8-42 weeks of MST. Induction or neoadjuvant therapies
for advanced NSCLC, with 40-69% of RR, 25-29% of complete resection rate, 8-34%
of CR and 17-45% of one year SR are reviewed. Eight random studies comparing MST
between CT with C-DDP and best supportive care for NSCLC are statistically
significant. (2) RT for Stage III NSCLC with 2 year and 5 year survivals of 20
and 5% respectively. Although such outcome is hardly acceptable, RT sensitizer,
modified RT techniques and chemoradiotherapy (CRT) are imperative to improve the
effect of RT in advanced NSCLC. Clinical literature suggest that CRT is better
than RT, though without marked difference. Further studies and sufficient follow
up are necessary to judge the efficacy in terms of long-term survival and toxic
reaction. (3) Biological therapy: gene therapy of NSCLC is still in the
experimental and developmental stage. Of biological response modifier (BRM),
alpha IFN in 11 cases of NSCLC with RR of 9% and MST of 14 months, IL-2 and LAK
cell treatment in 11 cases with RR of 9% and MST of 18 months are reported.
Instillation of BRM such as IL-2 or alpha-IFN into the pleura after drainage of
cancerous effusion has been reported as the most effective for those whose RR is
of 80-90% and the clinical response time is fairly long. Hematological cytokine
as a protective adjuvant therapy against CT/RT toxicity makes high dose of CT
possible and raises the response and patient tolerance. In multimodality therapy,
it plays an important role to reduce post CT infection and septicemia.
PMID- 9767612
TI - Chemotherapy for advanced (stage IIIB and stage IV) non-small cell lung cancer:
the Hong Kong perspective.
AB - Non-small cell lung cancer (NSCLC) accounts for about 80% of all primary lung
cancers, and 60% of cases present as advanced stages IIIB and IV disease.
Traditionally, treatment of stages IIIB and IV disease was only symptomatic
(including radiotherapy) and supportive care, and cytotoxic chemotherapy was
relatively ineffective. Our initial clinical trials, using MACC, FuAM, FAM, Hi
FAM and cisplatin-VP16, gave response rates of 5-20% and a stabilization rate of
7-25%, with no impact on median survival. Our most recent chemotherapy regimen
MIP (mitomycin-C, ifosfamide and cisplatin) proved to be more effective with a
44% response rate and a 28% stabilzation rate, and produced a significantly
longer median survival (32 weeks) than best supportive care alone (19.5 weeks, P<
0.05). The response rate further increased to 62.5% with dose intensification and
GM-CSF support. Chemotherapy can now be recommended to motivated, well-informed
patients with good performance status in institutions with experience in cancer
chemotherapy on a protocol basis. The most recent addition of new effective
cytotoxic agents such as paclitaxel, docetaxel, gemitabine and vinorelbine gave
promising results in NSCLC, and optimal combinations and dose schedules are being
defined by multicentred studies.
PMID- 9767614
TI - Non-surgical therapy for the patients with advanced non-small cell lung cancer.
AB - Radiation therapy (RT) and chemotherapy have been the two main treatment
modalities for advanced non-small cell lung cancer (NSCLC). New techniques in RT,
including hyperfractination and 3-dimensional conformal RT (3-DCRT), have changed
conventional RT, which has been regarded as standard modality for locally
advanced NSCLC. Introduction of cisplatin into chemotherapeutic regimens for
NSCLC has changed the status of chemotherapy to standard therapy for patients
with stage IV or stage IIIb with effusion. Radiation therapy or chemotherapy
alone have already showed their limitations, even although they could improve the
survival of NSCLC patients. Combined treatments with these two have become
powerful alternatives for patients with unresectable and locally advanced NSCLC.
Sequential or concurrent chemoradiotherapy could improve the response rate and
survival rate without a remarkable increase in toxicities. Gene therapy is a
novel therapeutic approach based on molecular oncology and tumour immunology. The
practical contribution of gene therapy to clinical oncology is still minimal.
From the research data, gene therapy has shown its potential to become a new
treatment modality or to lead us to as yet undiscovered novel approaches to the
treatment of lung cancer.
PMID- 9767615
TI - Non-surgical treatment of advanced non-small cell lung cancer in Japan.
AB - The cisplatin-based conventional combination chemotherapy has been shown to
prolong survival of patients with advanced non-small cell lung cancer (NSCLC),
but the treatment effect is only modest and of little clinical significance.
Several promising 'new-generation' anti-cancer drugs, such as taxanes,
vinorelbine, gemcitabine and irinotecan, have offered both chance and challenge
to develop effective chemotherapy against NSCLC. In Japan, large-scale phase III
trials of cisplatin-irinotecan combination regimen vs. conventional chemotherapy
have been conducted; patient accrual has been completed and the final results
will be presented in a couple of years. Other new agents will also be available
by the end of 1999, and it will be our important task to evaluate those drugs
efficiently. The current standard treatment strategy against unresectable stage
III NSCLC is chemo- radiotherapy. However, there remain many questions to be
answered through well-designed clinical trials. Those include optimal timing and
schedule of the chemoradiotherapy, dose and fractionation of radiation and best
chemotherapy regimen. An important randomized trial of concurrent vs. sequential
chemoradiotherapy has been conducted in Japan, which has suggested that the
concurrent schedule has survival benefit. Many trials of concurrent
chemoradiotherapy with the new agents are currently performed or planned, but
potential toxicity of the concurrent chemoradiotherapy must be carefully
evaluated.
PMID- 9767616
TI - Non-surgical therapy for patients with advanced non-small cell lung cancer.
AB - Non-small cell lung cancer is the major cancer problem in the Western World.
Treatment and prognosis are highly stage dependent, although overall only 5-10%
of patients will be alive 5 years after diagnosis. Patients with early stage
disease are treated with surgery alone. However, for patients with locally
advanced disease there is increasing evidence that combined modality approaches,
incorporating chemotherapy, radiotherapy and/or surgery result in modest
improvements in survival. For patients with metastatic non-small cell lung cancer
there is evidence from metaanalyses and randomised studies that chemotherapy
results in improvements in both duration and quality of life. Despite these
advances, there is substantial room for further improvement and therefore,
wherever possible, patients should be enrolled in well designed clinical studies.
PMID- 9767617
TI - Clinical efficacy of the FLUTTER device for airway mucus clearance in patients
with diffuse panbronchiolitis.
AB - Expectoration of mucus is important in preventing the development of airway
inflammation in patients with diffuse panbronchiolitis (DPB). To evaluate the
clinical efficacy of the FLUTTER device in clearing mucus from the airways of
patients with DPB who have difficulty expectorating, we assessed pulmonary
function and symptoms in patients treated with FLUTTER. Eight patients in a
stable clinical condition with DPB were included in the study. The study was
divided into two consecutive, 1-week periods. The initial week was an observation
week. During the following week, patients used FLUTTER four times daily.
Expectorated sputum was collected in a container and weighed every day during 2
weeks. Pulmonary function, partial oxygen pressure and partial carbon dioxide
pressure in arterial blood were measured in all patients on the last day of the
observation week and the FLUTTER treatment week. A symptom score for difficulty
of expectoration was determined by questionnaire. A pneumothorax developed in one
patient during using FLUTTER. The mean daily sputum weight and peak expiratory
flow rate increased significantly after treatment with FLUTTER ( P< 0.04 and P<
0.02, respectively). Symptom score improved significantly after using FLUTTER (
P< 0.02). We conclude that the use of FLUTTER is effective in clearing mucus from
the airways. However, the development of a pneumothorax may complicate use of the
procedure in some cases.
PMID- 9767618
TI - Bronchiolitis obliterans organizing pneumonia in Korea.
AB - An analysis of the clinical features in 23 cases of bronchiolitis obliterans
organizing pneumonia (BOOP) in Korea is presented. Six were men and 17 were
female, with a male-to-female ratio of 1:2.4. Idiopathic BOOP was present in 18
of these patients, connective tissue disease-associated BOOP in five and all of
them were females. The most frequent symptoms were dyspnoea and coughing in both
groups; and crackles were the most prominent physical findings. Leukocytosis was
observed in seven of the idiopathic BOOP group and all in the connective tissue
disease-associated BOOP group. In most cases, FVC, FEV 1, diffusing capacity and
arterial O2 pressure were reduced. In roentgenographic study, patchy air space
consolidation was the major finding and subpleural predominance was observed in
the majority of patients in both groups. Migration of lesions were identified in
only two patients with idiopathic BOOP. Steroid treatment was effective in all of
idiopathic BOOP. In contrast to previous reports, an analysis of the 23 Korean
BOOP patients showed several interesting points. First, a female predominance was
observed. Second, migration of lesion was rare. Third, it did not show any
different prognosis in patients with reticular pattern on roentgenogram compared
with patients with patchy air space consolidation on roentgenogram. Whether these
differences were due to ethnic or environmental factors is to be determined.
PMID- 9767619
TI - Increased use of inhaled corticosteroids and reduced hospitalizations in adult
asthmatics: 11 years' experience in a Japanese hospital.
AB - Until recently, inhaled corticosteroids have not been recognized as a first-line
drug mainly because of the traditional polypharmaceutical approach to asthma in
Japan. To examine the trend more precisely following the introduction of inhaled
corticosteroids, we retrospectively analysed the relation between the number of
prescriptions for anti-asthma drugs including inhaled corticosteroids and the
number of hospitalizations due to asthma exacerbation, near fatal episodes and
deaths from asthma for a period of 11 years from 1986 to 1996 at Kobe City
General Hospital (KCGH). A marked decline in these actual indices in patients
attending KCGH, which shows the improvement in asthma control, started
coincidentally with the increased use of inhaled corticosteroid, which was
followed by both a discontinuation of the trend for increased use of inhaled beta
agonists and the decreased use of oral anti-asthma agents. There was no
significant difference in the mean duration of hospital stays between 1988 and
1996. Although the intensification of patient education is likely to play an
important role in enhancing the protective effect of inhaled corticosteroids, we
highly suspect that the major contributory factor in the great decline in
hospitalizations is the increased use of inhaled corticosteroids.
PMID- 9767621
TI - Correlation between clinical and pathological features of pulmonary thromboemboli
and the development of infarcts.
AB - Factors that predispose pulmonary thromboembolism to infarction have not been
completely understood. The present autopsy study was carried out to evaluate
these factors both clinically and pathologically. Between 36 subjects with
pulmonary infarction and 33 individuals who had multiple pulmonary
thromboembolism but no infarction, clinical and pathological features including
congestive heart failure (CHF), shock, sepsis, neoplasm, emphysema, pneumonia,
the amount of pleural effusion, diameter of occluded arteries, and segmental and
dimensional location of thromboemboli were compared. Multiple regression analysis
revealed that clinically CHF was significantly associated with the development of
infarction. In pathological factors, thromboemboli located in the distal artery
and in the lower lobe were significantly associated with infarction. The size of
the infarcts was small and all the complete infarcts were in contact with the
pleura. In addition to CHF, occlusion of small arteries in the lower lobe and
near the pleura seems to be associated with the occurrence of infarction.
PMID- 9767622
TI - CYFRA 21-1 and ProGRP, tumor markers of lung cancer, are elevated in chronic
renal failure patients.
AB - Serum levels of CYFRA 21-1(cytokeratin-19 fragment) and ProGRP (pro-gastrin
releasing peptide), the new prognostic markers of lung cancer, were measured by
ELISA (enzyme-linked immunoadsorbent assay) in 27 (for CYFRA 21-1; male 13,
female 14; age 54+/-17 years) or 22 (for ProGRP; male 9, female 13; age 59+/-18
years) patients with various serum creatinine levels, 42 haemodialysis (HD)
patients (male 24, female 18; age 59+/-14 years) and 30 continuous ambulatory
peritoneal dialysis (CAPD) patients (male 18, female 12; age 48+/-9 years). All
the patients were without clinical and radiological signs of lung cancer.
Positive correlations were found between serum creatinine and serum CYFRA 21-1
and ProGRP levels. Serum levels of CYFRA 21-1 were above the cutoff limit (3.5
ng/mL) in 57% of HD patients (mean 4.07+/-1.56 ng/mL) and in 73% of CAPD patients
(mean 4.87+/-1.56 ng/mL). Serum levels of ProGRP were above the cutoff limit
(46.0 pg/mL) in 90% of HD patients (mean 107.0+/-59.4 pg/mL) and in 93% of CAPD
patients (mean 112.4+/-44.5 pg/mL). Our data indicate that evaluation of renal
function is essential when the measurement of these tumor markers is to be
applied as one of the diagnostic tools of lung cancer.
PMID- 9767624
TI - Sarcoidosis in monozygotic twins.
PMID- 9767623
TI - Marked elevation of CA19-9 in a patient with idiopathic pulmonary fibrosis: CA19
9 as a bad prognostic factor.
AB - A 53-year-old Japanese female, who had been suffering from idiopathic pulmonary
fibrosis (IPF) for 3 years, was admitted with dyspnoea. The important laboratory
finding on admission was a serum CA19-9 level of 649 U/mL. Despite steroid
treatment for IPF, her respiratory condition gradually deteriorated with the
increase of serum CA19-9 level up to 3020 U/mL and she died of respiratory
failure. Immunohistochemistry showed the positive stain of CA19-9 in
bronchoepithelial cells. We also reviewed the Index Medics and picked up the
cases who had elevation of CA19-9 more than 1000 U/mL, and six patients were
listed. Five of these six patients died within 6 months, therefore the marked
elevation of CA19-9 seemed to be a bad prognostic factor in patients with
pulmonary fibrosis.
PMID- 9767620
TI - Comparative evaluation of sialylated carbohydrate antigens, KL-6, CA19-9 and SLX
as serum markers for interstitial pneumonia.
AB - We compared diagnostic values of three serum carbohydrate antigens, KL-6, CA19-9
and SLX to discriminate interstitial pneumonia (IP) from alveolar pneumonia and
healthy volunteers. Subjects consisted of 13 patients with idiopathic pulmonary
fibrosis and 10 associated with collagen vascular diseases, 12 patients with
sarcoidosis and 70 controls (52 healthy volunteers and 18 patients with alveolar
pneumonia). Cut-off values were determined at the level at which the diagnostic
accuracy became the highest for each marker, 449 U/mL for KL-6, 26 U/mL for CA19
9 and 41 U/mL for SLX. The sensitivity, the specificity and the diagnostic
accuracy were 74.3% (26/35), 98.6% (69/70) and 90.5% (95/105) in KL-6, 42.9%
(15/35), 94.3% (66/70) and 77.1% (81/105) in CA19-9, and 20.0% (7/35) and 95.7%
(67/70) and 70.5% (74/105) in SLX, respectively. Receiver operating
characteristic curves revealed that KL-6 was far superior to both CA19-9 and SLX.
These results suggest that KL-6 is the best marker for interstitial pneumonia
among these carbohydrate antigens.
PMID- 9767625
TI - Elevated soluble Fas levels in herpes zoster patients.
PMID- 9767626
TI - Manual of nail disease and surgery
PMID- 9767627
TI - Bullous pemphigoid with circulating autoantibodies against the basal and apical
lateral surfaces of the basal keratinocytes.
PMID- 9767628
TI - Syntheses of trans-5-oxo-hexahydro-pyrrolo[3,2-b]pyrroles and trans-5-oxo
hexahydro-furo[3,2-b]pyrroles (pyrrolidine trans-lactams and trans-lactones): new
pharmacophores for elastase inhibition.
PMID- 9767629
TI - Structure-based design of cathepsin K inhibitors containing a benzyloxy
substituted benzoyl peptidomimetic.
AB - Peptidomimetic cathepsin K inhibitors have been designed using binding models
which were based on the X-ray crystal structure of an amino acid-based, active
site-spanning inhibitor complexed with cathepsin K. These inhibitors, which
contain a benzyloxybenzoyl group in place of a Cbz-leucine moiety, maintained
good inhibitory potency relative to the amino acid-based inhibitor, and the
binding models were found to be very predictive of relative inhibitor potency.
The binding mode of one of the inhibitors was confirmed by X-ray crystallography,
and the crystallographically determined structure is in close qualitative
agreement with the initial binding model. These results strengthen the validity
of a strategy involving iterative cycles of structure-based design, inhibitor
synthesis and evaluation, and crystallographic structure determination for the
discovery of peptidomimetic inhibitors.
PMID- 9767630
TI - Investigations of neurotrophic inhibitors of FK506 binding protein via Monte
Carlo simulations.
AB - The binding and solution-phase properties of six inhibitors of FK506 binding
protein (FKBP12) were investigated using free energy perturbation techniques in
Monte Carlo statistical mechanics simulations. These nonimmunosuppressive
molecules are of current interest for their neurotrophic activity when bound to
FKBP12 as well as for their potential as building blocks for chemical inducers of
protein dimerization. Relative binding affinities were computed and analyzed for
ligands differing by a phenyl ring, an external phenyl or pyridyl substituent,
and a pipecolyl or prolyl ring. Such results are, in general, valuable for
inhibitor optimization and, in the present case, bring into question some of the
previously reported binding data.
PMID- 9767631
TI - N-[omega-(Tetralin-1-yl)alkyl] derivatives of 3,3-dimethylpiperidine are highly
potent and selective sigma1 or sigma2 ligands.
AB - Several 3, 3-dimethyl-N-[omega-(tetrahydronaphthalen-1-yl)alkyl]piperidine
derivatives and some related compounds were prepared. Their affinities and sigma
subtype selectivities were investigated by radioligand binding assays, labeling
sigma1 receptors with [3H]-SKF 10047 and sigma2 receptors with [3H]-DTG. Many
tested compounds bound sigma1 and/or sigma2 receptors with nanomolar or
subnanomolar IC50 values. Compound (+)-22, (+)-3,3-dimethyl-1-[3-(5-methoxy
1,2,3, 4-tetrahydronaphthalen-1-yl)-n-propyl]piperidine, was the most potent
(IC50 = 0.089 nM) and selective sigma1 ligand (1340-fold), showing a 10-fold
enantioselectivity. Compounds 29 (3, 3-dimethyl-1-[4-(6-methoxy-1,2,3, 4
tetrahydronaphthalen-1-yl)-n-butyl]piperidine) and 31 (3, 3-dimethyl-1-[5-(1,2,3,
4-tetrahydronaphthalen-1-yl)-n-pentyl]piperidine) were highly potent (IC50 =
0.016 nM and IC50 = 0.008 nM, respectively) and highly selective sigma2 ligands
(more than 100000-fold).
PMID- 9767632
TI - Geometrically and conformationally restrained cinnamoyl compounds as inhibitors
of HIV-1 integrase: synthesis, biological evaluation, and molecular modeling.
AB - Various cinnammoyl-based structures were synthesized and tested in enzyme assays
as inhibitors of the HIV-1 integrase (IN). The majority of compounds were
designed as geometrically or conformationally constrained analogues of caffeic
acid phenethyl ester (CAPE) and were characterized by a syn disposition of the
carbonyl group with respect to the vinylic double bond. Since the cinnamoyl
moiety present in flavones such as quercetin (inactive on HIV-1-infected cells)
is frozen in an anti arrangement, it was hoped that fixing our compounds in a syn
disposition could favor anti-HIV-1 activity in cell-based assays. Geometrical and
conformational properties of the designed compounds were taken into account
through analysis of X-ray structures available from the Cambridge Structural
Database. The polyhydroxylated analogues were prepared by reacting 3,4
bis(tetrahydropyran-2-yloxy)benzaldehyde with various compounds having active
methylene groups such as 2-propanone, cyclopentanone, cyclohexanone, 1,3
diacetylbenzene, 2, 4-dihydroxyacetophenone, 2,3-dihydro-1-indanone, 2,3-dihydro
1, 3-indandione, and others. While active against both 3'-processing and strand
transfer reactions, the new compounds, curcumin included, failed to inhibit the
HIV-1 multiplication in acutely infected MT-4 cells. Nevertheless, they
specifically inhibited the enzymatic reactions associated with IN, being totally
inactive against other viral (HIV-1 reverse transcriptase) and cellular (RNA
polymerase II) nucleic acid-processing enzymes. On the other hand, title
compounds were endowed with remarkable antiproliferative activity, whose potency
correlated neither with the presence of catechols (possible source of reactive
quinones) nor with inhibition of topoisomerases. The SARs developed for our
compounds led to novel findings concerning the molecular determinants of IN
inhibitory activity within the class of cinnamoyl-based structures. We
hypothesize that these compounds bind to IN featuring the cinnamoyl residue C=C
C=O in a syn disposition, differently from flavone derivatives characterized by
an anti arrangement about the same fragment. Certain inhibitors, lacking one of
the two pharmacophoric catechol hydroxyls, retain moderate potency thanks to
nonpharmacophoric fragments (i.e., a m-methoxy group in curcumin) which favorably
interact with an "accessory" region of IN. This region is supposed to be located
adjacent to the binding site accommodating the pharmacophoric dihydroxycinnamoyl
moiety. Disruption of coplanarity in the inhibitor structure abolishes activity
owing to poor shape complementarity with the target or an exceedingly high strain
energy of the coplanar conformation.
PMID- 9767634
TI - Structure-based design of beta-lactamase inhibitors. 2. Synthesis and evaluation
of bridged sulfactams and oxamazins.
AB - A series of bridged monocyclic beta-lactams activated by various groups on the
beta-lactam nitrogen (X = OCH2CO2H, OSO3H) has been synthesized and evaluated.
Among them, the bridged sulfactams (X = OSO3H) were found to be effective beta
lactamase inhibitors. They inhibit both class A and class C beta-lactamases.
PMID- 9767633
TI - Structure-based design of beta-lactamase inhibitors. 1. Synthesis and evaluation
of bridged monobactams.
AB - Bridged monobactams are novel, potent, mechanism-based inhibitors of class C beta
lactamases, designed using X-ray crystal structures of the enzymes. They
stabilize the acyl-enzyme intermediate by blocking access of water to the enzyme
inhibitor ester bond. Bridged monobactams are selective class C beta-lactamase
inhibitors, with half-inhibition constants as low as 10 nM, and are less
effective against class A and class B enzymes (half-inhibition constants > 100
microM) because of the different hydrolysis mechanisms in these classes of beta
lactamases. The stability of the acyl-enzyme complexes formed with class C beta
lactamases (half-lives up to 2 days were observed) enabled determination of their
crystal structures. The conformation of the inhibitor moiety was close to that
predicted by molecular modeling, confirming a simple reaction mechanism, unlike
those of known beta-lactamase inhibitors such as clavulanic acid and penam
sulfones, which involve secondary rearrangements. Synergy between the bridged
monobactams and beta-lactamase-labile antibiotics could be observed when such
combinations were tested against strains of Enterobacteriaceae that produce large
amounts of class C beta-lactamases. The minimal inhibitory concentration of the
antibiotic of more than 64 mg/L could be decreased to 0.25 mg/L in a 1:4
combination with the inhibitor.
PMID- 9767635
TI - Acetylcholinesterase inhibitors: synthesis and structure-activity relationships
of omega-[N-methyl-N-(3-alkylcarbamoyloxyphenyl)- methyl]aminoalkoxyheteroaryl
derivatives.
AB - Acetylcholinesterase (AChE) inhibitors are one of the most actively investigated
classes of compounds in the search for an effective treatment of Alzheimer's
disease. This work describes the synthesis, AChE inhibitory activity, and
structure-activity relationships of some compounds related to a recently
discovered series of AChE inhibitors: the omega-[N-methyl-N-(3
alkylcarbamoyloxyphenyl)methyl]aminoalkoxy xanthen-9-ones. The influence of
structural variations on the inhibitory potency was carefully investigated by
modifying different parts of the parent molecule, and a theoretical model of the
binding of one representative compound to the enzyme was developed. The
biological properties of the series were investigated in some detail by
considering not only the activity on isolated enzyme but the selectivity with
respect to butyrylcholinesterase (BuChE) and the in vitro inhibitory activity on
rat cerebral cortex as well. Some of the newly synthesized derivatives, when
tested on isolated and/or AChE-enriched rat brain cortex fraction, displayed a
selective inhibitory activity and were more active than physostigmine. In
particular, compound 13, an azaxanthone derivative, displayed the best rat cortex
AChE inhibition (190-fold higher than physostigmine), as well as a high degree of
enzyme selectivity (over 60-fold more selective for AChE than for BuChE). When
tested in the isolated enzyme, compound 13 was less active, suggesting some
differences either in drug availability/biotransformation or in the inhibitor
sensitive residues of the enzyme when biologically positioned in rat brain
membranes.
PMID- 9767636
TI - A novel class of adenosine A3 receptor ligands. 1. 3-(2-Pyridinyl)isoquinoline
derivatives.
AB - A series of 3-(2-pyridinyl)isoquinoline derivatives was synthesized as potential
antagonists for the human adenosine A3 receptor by substitution of the 1
position. The compounds were obtained by various synthetic routes from 1-amino-3
(2-pyridinyl)isoquinoline. The affinity was determined in radioligand binding
assays for rat brain A1 and A2A receptors and for the cloned human A3 receptor. A
structure-activity relationship analysis indicated that a phenyl group when
coupled by a spacer allowing conjugation on position 1 of the isoquinoline ring
increased the adenosine A3 receptor affinity. In contrast, such a phenyl group
directly bound to position 1 of the isoquinoline ring decreased affinity. Since
the combination of a phenyl group together with a spacer raised adenosine A3
receptor affinity, various spacers were investigated. VUF8501 (N-[3-(2
pyridinyl)isoquinolin-1-yl]benzamidine (15) showed an affinity at the human
adenosine A3 receptor of 740 nM. Substituent effects on the phenyl group were
investigated by in vitro evaluation of a series of substituted benzamidines.
Electron-donating groups at the para position of the benzamidine ring increased
adenosine A3 receptor affinity. These investigations led to VUF8505 (4-methoxy-N
[3-(2-pyridinyl)isoquinolin-1-yl]benzamidine(22)), which is a moderately potent
and selective ligand for the human adenosine A3 receptor with an affinity of 310
nM in our test system having negligible affinity for rat A1 and A2A receptors.
PMID- 9767637
TI - A novel class of adenosine A3 receptor ligands. 2. Structure affinity profile of
a series of isoquinoline and quinazoline compounds.
AB - 1-Substituted 3-(2-pyridinyl)isoquinolines have been shown to form a novel class
of adenosine A3 receptor ligands. In the present study further investigations of
this new lead and the structure affinity relationships of this class of compounds
are described. First, the influence of an amide group at position 1 of the
isoquinoline ring on the adenosine A3 receptor affinity was determined. A
carboxamide proved to be a useful spacer between the isoquinoline and a phenyl
ring. N-[2-(2-pyridinyl)isoquinolin-4-yl]benzamide (VUF8507, compound 6) had an
affinity of 200 nM at the adenosine A3 receptor. Second, we investigated the
effects of substitution of the benzamide ring of 6 with a series of mono- and
disubstituted N-[3-(2-pyridinyl)isoquinoline]benzamides. The ratio of the
tautomers of the benzamides was determined in the solid state and in solution by
spectroscopic techniques (IR and NMR). Affinities were determined in radioligand
binding assays at rat brain A1 and A2A receptors and at cloned human A3 receptor.
The benzamides showed higher adenosine A3 receptor affinity than aliphatic
amides. We propose that the adenosine A3 receptor affinity of the different
benzamides is related to their presence in either the iminol or amide form.
Ligands present in the iminol form showed relatively high adenosine A3 receptor
affinity. Finally, we explored the influence of replacement of C4 of the
isoquinoline ring by a nitrogen atom. Comparison of isoquinolines with the
corresponding quinazolines revealed that both compounds showed similar adenosine
A3 receptor affinity. These investigations led to potent and selective human
adenosine A3 receptor ligands with affinities in the nanomolar range. The subtype
selective compound 4-methoxy-N-[2-(2-pyridinyl)quinazolin-4-yl]benzamide
(VUF8504, 13) with an affinity of 17.0 nM at the human adenosine A3 receptor
might become a useful tool in the pharmacological characterization or the
investigation of the physiological function of this receptor.
PMID- 9767638
TI - Substituted 4-acylpyrazoles and 4-acylpyrazolones: synthesis and multidrug
resistance-modulating activity.
AB - A series of 4-acyl-3-pyrazolone derivatives with a 3-substituted 2-hydroxy-3
aminopropyl chain attached to pyrazole N-1 (7-20) as well as isomeric 4-acyl-5-(3
substituted 3-amino-2-hydroxypropoxy)pyrazole derivatives (5, 6) were
synthesized, and their multidrug resistance (MDR)-modulating activity was
measured using the daunomycin efflux assay. Reaction of N1-substituted 4-acyl-3
pyrazolones (tautomer to 4-acyl-5-hydroxypyrazoles) with excessive
epichlorohydrin and successive treatment with an appropriate amine resulted in N
alkylation and thus afforded the target pyrazolone derivatives 7-20. In contrast,
O-alkylation occurred upon reaction with 1 equiv of epichlorohydrin and
subsequent treatment with amine leading to the corresponding 4-acyl-5-pyrazolyl
ethers 5 and 6. QSAR studies showed a good correlation of MDR-modulating activity
with lipophilicity of the compounds. Inclusion of hydrogen bond acceptor strength
and steric parameters as descriptors led to a QSAR equation with remarkably
increased predictive power (r2cv = 0.92). Additionally, ortho substitution of the
propanolamine side chain and the acyl moiety is favorable. Detailed NMR
spectroscopic investigations were carried out with the title compounds.
PMID- 9767639
TI - 4-(beta-Arylvinyl)-3-(beta-arylvinylketo)-1-ethyl-4-piperidinols and related
compounds: a novel class of cytotoxic and anticancer agents.
AB - The syntheses of a series of 1-aryl-5-diethylamino-1-penten-3-one hydrochlorides
1 and 1-aryl-3-diethylamino-1-propanone hydrochlorides 4 were accomplished.
Attempts to prepare the corresponding bis(5-aryl-3-oxo-4-pentenyl)ethylamine
hydrochlorides 2 and bis(3-aryl-3-oxopropyl)ethylamine hydrochlorides 5 led to
the formation of a series of 4-(beta-arylvinyl)-3-(beta-arylvinylketo)-1-ethyl-4
piperidi nol hydrochlorides 9 and 4-aryl-3-arylketo-1-ethyl-4-piperidinol
hydrochlorides 11, most of which were converted subsequently into the
corresponding quaternary ammonium salts 10 and 12, respectively. The structures
of these compounds were determined by 1H NMR spectroscopy and confirmed by X-ray
crystallography of representative molecules. Most compounds displayed significant
cytotoxicity toward murine P388 and L1210 cells as well as human tumors. In
general, Mannich bases containing olefinic bonds were more cytotoxic than the
analogues without this functional group, while the piperidines 9 and 11 were more
potent than the acyclic analogues 1 and 4, respectively. Correlations were noted
between various physicochemical constants in the aryl rings and cytotoxicity.
Compound 9d displayed promising in vivo activity against colon cancers. This
study has revealed that the piperidines 9 and 11 constitute new classses of
cytotoxic agents.
PMID- 9767640
TI - Design, synthesis, and biological activities of new thieno[3,2-d] pyrimidines as
selective type 4 phosphodiesterase inhibitors.
AB - A common pharmacophore for compounds structurally related to nitraquazone has
been derived. Using this pharmacophore, new structures have been designed,
synthesized, and evaluated for their inhibitory potencies against cyclic
adenosine 5'-monophosphate (cAMP) specific phosphodiesterase (PDE 4). From these
compounds, 4-benzylamino-2-butylthieno[3,2-d]pyrimidine (4) was selected for
optimization. The effects of changes to the lipophilic groups and the amino
linkage on the PDE 4 activity have been investigated. As a result, some potent
PDE 4 inhibitors, selective with respect to PDE 3, have been identified. A
selected group of compounds have been further evaluated for their ability to
displace [3H]rolipram from its binding site and also to potentiate isoprenaline
induced cAMP accumulation in isolated guinea pig eosinophils. Of these, 2-butyl-4
cyclohexylaminothieno[3,2-d]pyrimidine (33) has an interesting profile, with an
important improvement in PDE 4/[3H]rolipram ratio with respect to reference
drugs, and good activity in cAMP potentiation, consistent with efficient cell
penetration.
PMID- 9767641
TI - New platelet fibrinogen receptor glycoprotein IIb-IIIa antagonists: orally active
series of N-alkylated amidines with a 6,6-bicyclic template.
AB - The design, synthesis, and pharmacological evaluation of (S)-(-)-ethyl [6-[4
(morpholinoformimidoyl)benzamido]-3, 4-dihydro-2H-1-benzopyran-3-yl]acetate
hydrochloride ((S)-4.HCl, MS-180), an orally active glycoprotein IIb-IIIa (GPIIb
IIIa) antagonist, are reported. Pharmacophore mapping of amidino and carboxyl
groups of already known GPIIb-IIIa antagonists led to the synthesis of nine
amidino acids containing 6,6-bicyclic ring skeletons (10a-i). Among them, the
compounds 10a,c,e having an amide bond and 1,2,3,4-tetrahydronaphthalene or 3, 4
dihydro-2H-1-benzopyran skeleton showed marked inhibitions with IC50 values of 46
57 nM in human platelet aggregation assay in vitro, but low oral activities. N
Alkylation of the amidino group coupled with the ester prodrug approach afforded
MS-180 ((S)-4.HCl), which generates in vivo the corresponding carboxylic acid (S)
3 as an active species. In vitro, (S)-3 inhibited ADP-induced aggregation of
guinea pig, dog, and human platelets (IC50 = 110, 253, and 35 nM, respectively)
and inhibited the binding of fibrinogen to immobilized GPIIb-IIIa of human
platelets (IC50 = 0.12 nM). After oral administration of MS-180 ((S)-4.HCl) to
fasted beagle dog, ex vivo inhibition of platelet aggregation was observed. The
maximal inhibitions were observed 2-4 h after dosing with dose dependency (60%
inhibition at a dose of 1 mg/kg, 85% at 3 mg/kg, and 100% at 10 mg/kg,
respectively) and the extent of the inhibitions paralleled the plasma
concentration of the active species (S)-3. On the basis of these studies, we
selected MS-180 ((S)-4.HCl) as a candidate for clinical evaluation as a drug for
the treatment and prevention of thrombosis in patients.
PMID- 9767642
TI - A novel class of orally active non-peptide bradykinin B2 receptor antagonists. 2.
Overcoming the species difference between guinea pig and man.
AB - Recently we reported the identification of a series of 8-[[3-(N-acylglycyl-N
methylamino)-2, 6-dichlorobenzyl]oxy]-3-halo-2-methylimidazo[1,2-a]pyridines as
the first orally active non-peptide bradykinin (BK) B2 receptor antagonists (1
3). These compounds inhibited the specific binding of [3H]BK to guinea pig ileum
membrane preparations expressing B2 receptors with nanomolar IC50's and also
displayed in vivo functional antagonistic activities against BK-induced
bronchoconstriction in guinea pigs at 1 mg/kg by oral administration. However, it
was found that their affinities for the B2 receptors in human A-431 cells (human
epidermoid carcinoma) were much lower. Intensive modifications of the terminal
substituents at the glycine moiety elucidated the structure-activity
relationships (SAR) for human B2 receptors, leading to an extended basic
framework which incorporated a novel key pharmacophore. Thus, we overcame the
species difference and identified the first clinical candidate 18c (FR167344)
with IC50's of 0.66 and 1.4 nM for guinea pig ileum and human A-431 cells,
respectively. This compound displayed in vivo functional antagonistic activity
against BK-induced bronchoconstriction in guinea pigs with an ED50 value of 0.17
mg/kg by oral administration. This novel non-peptide B2 antagonist is extremely
potent both in vitro and in vivo by oral administration and is expected to be the
first member of a new class of drug for the treatment of various inflammatory
diseases.
PMID- 9767643
TI - A novel class of orally active non-peptide bradykinin B2 receptor antagonists. 3.
Discovering bioisosteres of the imidazo[1,2-a] pyridine moiety.
AB - Recently we reported on overcoming the species difference of our first orally
active non-peptide bradykinin (BK) B2 receptor antagonists, incorporating an 8
[[3-(N-acylglycyl-N-methylamino)-2, 6-dichlorobenzyl]oxy]-3-halo-2
methylimidazo[1,2-a]pyridine skeleton, leading to identification of the first
clinical candidate 4a (FR167344). With this potent new lead compound in hand, we
then investigated further refinement of the basic framework by replacement of the
imidazo[1,2-a]pyridine moiety and discovered several bioisosteric heterocycles.
Extensive optimization of these new heteroaromatic derivatives revealed the
detailed structure-activity relationships (SAR) around the imidazo[1, 2
a]pyridine ring and the 2,6-dichlorobenzyl moiety, leading to the discovery of
our second clinical candidate 87b (FR173657) which inhibited the specific binding
of [3H]BK to recombinant human B2 receptors expressed in Chinese hamster ovary
(CHO) cells and guinea pig ileum membrane preparations expressing B2 receptors
with IC50's of 1.4 and 0.46 nM, respectively. This compound also displayed
excellent in vivo functional antagonistic activity against BK-induced
bronchoconstriction in guinea pigs with an ED50 value of 0.075 mg/kg by oral
administration. Further modifications of the terminal substituents on the
pyridine moiety led to a novel pharmacophore and resulted in the identification
of 99 (FR184280), whose IC50 value for human B2 receptors (0.51 nM) was
comparable to that of the second-generation peptide B2 antagonist Icatibant.
PMID- 9767644
TI - Synthesis and antibacterial activity of ketolides (6-O-methyl-3-oxoerythromycin
derivatives): a new class of antibacterials highly potent against macrolide
resistant and -susceptible respiratory pathogens.
AB - In the search for new antibiotics active against macrolide-resistant pneumococci
and Haemophilus influenzae, we synthesized a new class of 3-oxo-6-O
methylerythromycin derivatives, so-called "ketolides". A keto function was
introduced in position 3 after removal of L-cladinose, a sugar which has long
been thought essential. Further modifications of the macrolactone backbone
allowed us to obtain three different series of 9-oxime, 11,12-carbamate, and 11,
12-hydrazonocarbamate ketolides. These compounds were found to be very active
against penicillin/erythromycin-resistant pneumococci and noninducers of MLSB
resistance. The 11,12-substituted ketolide 61 (HMR 3004) demonstrated a potent
activity against multiresistant pneumococci associated with a well-balanced
activity against all bacteria involved in respiratory infections including H.
influenzae, Mycoplasma catarrhalis, group A streptococci, and atypical bacteria.
In addition HMR 3004 displayed high therapeutic activity in animals infected by
all major strains, irrespective of their resistance phenotype.
PMID- 9767645
TI - Synthesis and antimalarial activities of fluoroalkyl derivatives of
dihydroartemisinin.
AB - Fluoroalkyl ethers (4) of dihydroartemisinin (2) have been prepared by reaction
of fluoroalkyl alcohols with dihydroartemisinin by different methods (BF3,Et2O or
TMSCl catalysis or Mitsunobu reaction). Ethers 4a-d derived from primary
fluoroalkyl alcohols were obtained in moderate to good yields by these methods.
Ethers 4e-j have been prepared from fluoroalkyl secondary and tertiary alcohols
and phenol using the Mitsunobu reaction. Although in vitro antimalarial
activities of ethers toward Plasmodium falciparum W-2 asiatic strain are
moderate, in vivo activities against Plasmodium berghei (NT 173) are excellent.
PMID- 9767646
TI - Novel 1,1,3-trioxo-2H,4H-thieno[3,4-e][1,2,4]thiadiazine derivatives as non
nucleoside reverse transcriptase inhibitors that inhibit human immunodeficiency
virus type 1 replication.
AB - The 1,1,3-trioxo-2H,4H-thieno[3,4-e][1,2,4]thiadiazines (TTDs) represent a
recently discovered chemical class of non-nucleoside reverse transcriptase
inhibitors that selectively block human immunodeficiency virus type 1
replication. In a search for a better understanding of their mode of binding and
with the aim of obtaining novel lead compounds, a second series of TTD
derivatives was synthesized and evaluated for antiviral activity. The design of
the new compounds was based on a variety of chemical modifications which were
carried out in the original prototype 20a (QM 96521). Substitution of a halogen
at the meta position of the N-2 benzyl group resulted in an improvement of the
antiviral activity by 1 order of magnitude. Compounds bearing at the N-4 position
a cyanomethyl, propargyl, or benzyl substituent were found to be the most potent
of the series. Modifying the thieno[3,4-e] ring fused to the 1,2,4-thiadiazine
moiety to other heterocyclic ring systems decreased the potency. The results
obtained in this investigation have provided new indications for the design of
even more effective TTDs.
PMID- 9767647
TI - Novel, highly potent aldose reductase inhibitors: (R)-(-)-2-(4-bromo-2
fluorobenzyl)-1,2,3,4- tetrahydropyrrolo[1,2-a]pyrazine -4-spiro-3'-pyrrolidine
1,2',3,5'-tetrone (AS-3201) and its congeners.
AB - A series of novel tetrahydropyrrolo[1,2-a]pyrazine derivatives were synthesized
and evaluated as aldose reductase inhibitors (ARIs) on the basis of their
abilities to inhibit porcine lens aldose reductase (AR) in vitro and to inhibit
sorbitol accumulation in the sciatic nerve of streptozotocin-induced diabetic
rats in vivo. Of these compounds, spirosuccinimide-fused tetrahydropyrrolo[1, 2
a]pyrazine-1,3-dione derivatives showed significantly potent AR inhibitory
activity. In the in vivo activity of these derivatives, 2-(4-bromo-2
fluorobenzyl)-1,2,3,4-tetrahydropyrrolo[1, 2-a]pyrazine-4-spiro-3'-pyrrolidine
1,2',3,5'-tetrone (23t) (SX-3030) showed the best oral activity. The enantiomers
of 23t were synthesized, and the biological activities were evaluated. It was
found that AR inhibitory activity resides in the (-)-enantiomer 43 (AS-3201),
which was 10 times more potent in inhibition of the AR (IC50 = 1.5 x 10(-8) M)
and 500 times more potent in the in vivo activity (ED50 = 0.18 mg/kg/day for 5
days) than the corresponding (+)-enantiomer 44 (SX-3202). From these results, AS
3201 was selected as the candidate for clinical development. The absolute
configuration of AS-3201 was also established to be (R)-form by single-crystal X
ray analysis. In this article we report the preparation and structure-activity
relationship (SAR) of tetrahydropyrrolopyrazine derivatives including a novel
ARI, AS-3201.
PMID- 9767648
TI - Predictive models for GABAA/benzodiazepine receptor subtypes: studies of
quantitative structure-activity relationships for imidazobenzodiazepines at five
recombinant GABAA/benzodiazepine receptor subtypes [alphaxbeta3gamma2 (x = 1-3,
5, and 6)] via comparative molecular field analysis.
AB - Affinities of a series of substituted imidazobenzodiazepines at recombinant
alpha1beta3gamma2, alpha2beta3gamma2, alpha3beta3gamma2, alpha5beta3gamma2, and
alpha6beta3gamma2 GABAA/benzodiazepine receptor subtypes are reported. Many of
these ligands displayed high affinities (low-nanomolar to subnanomolar scale) at
all five receptor subtypes. Furthermore, a number of imidazobenzodiazepines
exhibited relatively good selectivity at the alpha5-containing receptor isoform.
For example, ligand 27 (RY-023) demonstrated a 55-fold higher selectivity at
alpha5beta3gamma2 isoforms in comparison to other receptor subtypes. The affinity
ratio of alpha1 (the most prevalent subtype in the brain) to alpha5 of this
series of ligands ranged from 60- to 75-fold for the most selective ligands.
Studies of quantitative structure-activity relationships (QSAR) by means of
comparative molecular field analysis (CoMFA) were carried out. As a result,
examination of CoMFA models for all five receptor subtypes demonstrated their
predictability for affinities of imidazobenzodiazepines at the five receptor
subtypes. Regions of molecular fields which would favor or disfavor the binding
affinity of a ligand at a specific receptor subtype were examined via CoMFA for
alpha1, alpha2, alpha3, alpha5, and alpha6 subtypes. A CoMFA regression analysis
was applied to predict the ratio of Ki alpha1/Ki alpha5, an index for the
selectivity of a ligand at the alpha5 subtype. All of the CoMFA models offered
good cross-validated correlations for the ligands in the test set as well as the
ratios of Ki alpha1/Ki alpha5, which demonstrated their potential for prediction.
PMID- 9767649
TI - N-Substituted 9beta-methyl-5-(3-hydroxyphenyl)morphans are opioid receptor pure
antagonists.
AB - The inhibition of radioligand binding and [35S]GTPgammaS functional assay data
for N-methyl- and N-phenethyl-9beta-methyl-5-(3-hydroxyphenyl)morphans (5b and
5c) show that these compounds are pure antagonists at the micro, delta, and kappa
opioid receptors. Since 5b and 5c have the 5-(3-hydroxyphenyl) group locked in a
conformation comparable to an equatorial group of a piperidine chair
conformation, this information provides very strong evidence that opioid
antagonists can interact with opioid receptors in this conformation. In addition,
it suggests that the trans-3, 4-dimethyl-4-(3-hydroxyphenyl)piperidine class of
antagonist operates via a phenyl equatorial piperidine chair conformation.
Importantly, the close relationship between the 4-(3-hydroxyphenyl)piperidines
and 5-(3-hydroxyphenyl)morphan antagonists shows that the latter class of
compound provides a rigid platform on which to build a novel series of opioid
antagonists.
PMID- 9767650
TI - Universal template approach to drug design: polyamines as selective muscarinic
receptor antagonists.
AB - The concept that polyamines may represent a universal template in the receptor
recognition process is embodied in the design of new selective muscarinic
ligands. Tetraamines 4-7 and 16-20 and diamine diamides 8-15 were synthesized,
and their pharmacological profiles at muscarinic receptor subtypes were assessed
by functional experiments in isolated guinea pig left atrium (M2) and ileum (M3)
and by binding assays in rat cortex (M1), heart (M2), submaxillary gland (M3),
and NG 108-15 cells (M4). It has been confirmed that appropriate substituents on
the terminal nitrogens of a tetraamine template can tune both affinity and
selectivity for muscarinic receptors. The novel tetraamine C-tripitramine (17)
was able to discriminate significantly M1 and M2 receptors versus the other
subtypes, and in addition it was 100-fold more lipophilic than the lead compound
tripitramine. Compound 14 (tripinamide), in which the tetraamine backbone was
transformed into a diamine diamide one, retained high affinity for muscarinic
subtypes, displaying a binding affinity profile (M2 > M1 > M4 > M3) qualitatively
similar to that of tripitramine. Both these ligands, owing to their improved
lipophilicity relative to tripitramine and methoctramine, could serve as tools in
investigating cholinergic functions in the central nervous system. Furthermore,
notwithstanding the fact that the highest affinity was always associated with
muscarinic M2 receptors, for the first time polyamines were shown to display high
pA2 values also toward muscarinic M3 receptors.
PMID- 9767651
TI - Halogenated chalcones with high-affinity binding to P-glycoprotein: potential
modulators of multidrug resistance.
AB - Previous studies have shown that flavonoids are modulators of the transmembrane P
glycoprotein (P-gp) which mediates cell multidrug resistance. Some structural
elements have been identified which seem to contribute to these compounds'
activity. In the present study, a series of halogenated chalcones was prepared to
further explore the structural requirements for the P-gp modulation. Four
halogenated chalcones have been synthesized and evaluated as potential modulators
of P-gp-mediated multidrug resistance of cancer cells by in vitro assays using a
purified recombinant domain of the transporter containing the modulator binding
site. Halogenated chalcones exhibited high-affinity binding, the 2',4', 6'
trihydroxy-4-iodochalcone behaving as the most potent compound with a KD value in
the nanomolar range.
PMID- 9767652
TI - N-(Iodopropenyl)-octahydrobenzo[f]- and -[g]quinolines: synthesis and adrenergic
and dopaminergic activity studies.
AB - A series of N-(iodopropenyl)-octahydrobenzo[f]- and -[g]quinolines was
synthesized and assayed in vitro for their dopaminergic and alpha-adrenergic
activity. Structure-activity relationship (SAR) analysis revealed that the tested
benzoquinolines exhibited activity at the D1 rather than the D2 receptor sites in
contrast to the D2 receptor subfamily activity reported for their aminotetralin
congeners. N-Iodopropenyl substitution was apparently a decisive factor for D1
activity independent of ring substitution pattern. Considering the structural
factors influencing alpha-adrenergic activity, in a general trend, N-iodopropenyl
analogues were alpha1-active, with the ring-hydroxylated congeners exhibiting the
highest affinity. Affinity to the alpha2 receptor was even higher with no
detectable trend of SAR. However, a combination of the linear arrangement of the
[g]-ring system, combined with the ring hydroxyl and the N-iodopropenyl
substitution in compound 5c, resulted in a significant enhancement of alpha2
activity in this series as demonstrated by an IC50 value of 0.5 nM. A new
synthetic approach to the [g]benzoquinoline system is also described.
PMID- 9767653
TI - 4-Alkynylphenyl imidazolylpropyl ethers as selective histamine H3-receptor
antagonists with high oral central nervous system activity.
AB - In search for potent and therapeutically useful H3-receptor antagonists, we
prepared novel 4-alkynylphenyl ether derivatives of 3-(1H-imidazol-4-yl)propanol
in a convenient synthetic route. All compounds were tested for in vitro and in
vivo H3-receptor antagonist activity as well as for H3-receptor selectivity
versus H1- and H2-receptors. The presented 4-alkynylphenyl ethers are highly
potent and selective H3 antagonists showing oral activity and improved brain
penetration. Particularly 4-ethynylphenyl 3-(1H-imidazol-4-yl)propyl ether (14a)
displays striking in vitro and in vivo activity with a -log Ki value of 8.6 and
an ED50 value of 0.12 mg/kg. At present 14a is the most potent H3-receptor
antagonist in vivo and may therefore be a potential drug for the therapy of H3
receptor-dependent diseases of the central nervous system (CNS).
PMID- 9767654
TI - 7-Arylidenenaltrexones as selective delta1 opioid receptor antagonists.
AB - A series of 7-arylidinenaltrexones (2a-m) related to the prototypical delta1
selective antagonist, 7-benzylidenenaltrexone 1 (BNTX), have been synthesized in
an effort to develop more selective ligands. Testing in smooth muscle
preparations revealed that members of the series exhibited varying degrees of
selectively for delta receptors, with the o-methoxy (2e) and o-chloro (2j)
congeners being most potent and most selective (Ke approximately 0.8 nm).
Evaluation of 1, 2e, and 2f sc in mice using the tail-flick procedure indicated
that they are selective delta1 opioid receptor antagonists in the lower dose
range. At high doses these ligands, including BNTX, exhibited decreased delta1
selectivity due to increases in the ED50 ratios of [D-Ser2,Leu5]enkephalin-Thr6
and morphine. It is concluded that 2e and 2f possess in vivo selectivity similar
to that of BNTX, but are less potent as delta1 antagonists.
PMID- 9767656
TI - In Situ Electron Microscopy: Introduction.
PMID- 9767655
TI - From the Editor.
PMID- 9767657
TI - Focused Ion Beam Interfaced with a 200 keV Transmission Electron Microscope for
In Situ Micropatterning on Semiconductors.
AB - : A focused ion beam (FIB) interface attached to a column of 200 keV transmission
electron microscope (TEM) was developed for in situ micropatterning to
semiconductors. TEM specimens of Si and GaAs, and those of a thin Ni2Si layer on
a Si substrate were micromilled in the TEM during observation. A set of 6 x 6-um
squares and alphabet letters were patterned with a 25 keV Ga+-FIB of 0.2-um beam
diameter at room temperature. The effect of FIB irradiation on the structural
evolution was observed simultaneously by a TV-rate video camera and sequentially
by regular film. FIB micropatterning to semiconductor specimens caused
amorphization and Ga injection. The excess Ga in the specimens precipitated as
metastable solid gamma-phase for Si and as liquid phase for GaAs. Ni2Si/Si
specimens lost silicide crystallinity after FIB patterning. Annealing of these
bilayer specimens at 673K resulted in the precipitation of Ni-rich silicide.
PMID- 9767658
TI - Time-Resolved High-Resolution Transmission Electron Microscopy Using a Piezo
Driving Specimen Holder for Atomic-Scale Mechanical Interaction.
AB - : Time-resolved high-resolution transmission electron microscopy at a spatial
resolution of 0.2 nm and a time resolution of 1/60 sec using a piezo-driving
specimen holder is reported here. Various types of atomic processes in mechanical
interaction, such as contact, bonding, deformation, and fracture, in nanometer
sized gold crystallites and carbon nanotubes are demonstrated.
PMID- 9767659
TI - High-Temperature In Situ Straining Experiments in the High-Voltage Electron
Microscope.
AB - : Design rules are described here for high-temperature straining stages for
transmission electron microscopy. Temperatures above 1000 degreesC can be
attained by electron bombardment of the specimen grips. Thermal equilibrium can
be reached in a short time by carrying off the heat by water cooling. Some
applications of this stage are described. Ferroelastic deformation was observed
at 1150 degreesC in t' and partially stabilized zirconia, which changes the
microstructure for successive dislocation plasticity. In the oxide-dispersion
strengthened alloy INCOLOY MA 956, dislocations are impeded by oxide particles
and move smoothly between the particles. At high temperatures, both the resting
and traveling times control the average dislocation velocity. In MoSi2 single
crystals of a soft orientation, dislocations with 1/2<111> Burgers vectors are
created in localized sources and move on {110} planes in a viscous manner. The
dislocations in Al-Pd-Mn single quasicrystals are oriented in preferred
crystallographic directions and move in a viscous way as well. On the basis of in
situ observations, conclusions are drawn for interpreting macroscopic deformation
behavior at high temperatures.
PMID- 9767660
TI - Understanding Interphase Boundary Dynamics by In Situ High-Resolution and Energy
Filtering Transmission Electron Microscopy and Real-Time Image Simulation.
AB - : This study discusses the use of in situ high-resolution transmission electron
microscropy (HRTEM) techniques to determine the structure, composition, and
interphase boundary dynamics during phase transformations at the atomic level.
Three main in situ HRTEM techniques are described: (1) in situ HRTEM dynamic
studies that are performed on the same precipitate plates from different viewing
directions to determine the three-dimensional structure of the interfaces; (2) in
situ compositional mapping of precipitate interfaces obtained by energy-filtering
TEM experiments at temperature in a HRTEM, and (3) real-time HRTEM image
simulations that are being created for comparison with and interpretation of
experimental in situ HRTEM dynamic observations. The results from these studies
demonstrate that it is possible to understand the mechanisms and kinetics of
interphase boundary motion at the atomic level.
PMID- 9767661
TI - Techniques for Studying Nanoparticle Sintering by Plan-View In Situ Transmission
Electron Microscopy.
AB - : We discuss various techniques for the characterization of supported
nanoparticles by in situ plan-view transmission electron microscopy. In
particular, we discuss here mechanisms of image contrast formation by particles
undergoing reorientation on the surface of a single crystal substrate. We
consider reorientation by a variety of mechanisms including rotation, sintering
and grain growth, and surface diffusion. Experimental observations are presented
and the data compared with theoretical predictions.
PMID- 9767663
TI - In Situ Transmission Electron Microscope Observation of Melting of Aluminum
Particles.
AB - ; The processes of melting and freezing of aluminum (Al) particles have been
observed directly in a transmission electron microscope. The liquid phase
nucleated preferentially at the surface of an Al particle, surrounding the
crystalline solid at the onset of melting. The liquid phase then propagated
inside the Al particle at the expense of the solid.
PMID- 9767662
TI - Ostwald Ripening of Self-Assembled Germanium Islands on Silicon(100).
AB - : We describe here real-time, in situ observations of the formation of nanosize
germanium (Ge) islands on silicon (Si). The deposition of Ge onto electron
transparent Si(100) takes place in a UHV transmission electron microscope that
has been modified to allow chemical vapor deposition to be carried out in the
polepiece. We recorded the growth process at video rate and were therefore able
to follow the evolution of individual islands. As the islands grew, we observed a
coarsening process similar to classical Ostwald ripening, but which leads at
certain times to a bimodal distribution of island sizes. We show that this
phenomenon can be understood using a model in which a conventional coarsening
process is modified by a transition between two different island shapes.
PMID- 9767664
TI - In Situ High-Temperature Transmission Electron Microscopy Observations of the
Formation of Nanocrystalline TiC from Nanocrystalline Anatase (TiO2).
AB - : In this work, the high-temperature behavior of nanocrystalline TiO2 is studied
using in situ transmission electron microscopy (TEM). These nanoparticles are
made using wet chemical techniques that generate the anatase phase of TiO2 with
average grain sizes of 6 nm. X-ray diffraction studies of nanophase TiO2 indicate
the material undergoes a solid-solid phase transformation to the stable rutile
phase between 600 degrees and 900 degreesC. This phase transition is not observed
in the TEM samples, which remain anatase up to temperatures as high as 1000
degreesC. Above 1000 degreesC, nanoparticles become mobile on the amorphous
carbon grid and by 1300 degreesC, all anatase diffraction is lost and larger (50
nm) single crystals of a new phase are present. This new phase is identified as
TiC both from high-resolution electron microscopy after heat treatment and
electron diffraction collected during in situ heating experiments. Video images
of the particle motion in situ show the nanoparticles diffusing and interacting
with the underlying grid material as the reaction from TiO2 to TiC proceeds.
PMID- 9767665
TI - Oxidation and Reduction of Small Palladium Particles on Silica.
AB - : We have used the technique of in situ electron microscopy to study the
oxidation and reduction of the palladium (Pd) catalysts. In this study, we have
subjected a Pd catalyst to oxidation and reduction cycles and studied the changes
in particle structure and morphology with in situ electron diffraction and
imaging. The PdO particles can be reduced to Pd metal in situ at temperatures as
low as 200 degreesC in an atmosphere of a few Torr of both H2 and O2. We also
found that essentially the same reduction occurred in the vacuums of 10(-6) to
10(-7) Torr in two different electron microscopes. Our in situ reduction studies
show that many of the oxide particles form voids when reduced to Pd metal. The
decrease in volume that occurs during reduction is often accommodated by a
combination of particle shrinkage and void formation. The production of voids
does not seem to depend on either the reducing atmosphere or the rate of
reduction, although the voids appear to be unstable above 500 degreesC.
PMID- 9767666
TI - In Situ Observations of the Interaction of Liquid Lead Inclusions with Grain
Boundaries in Aluminum.
AB - : The evolution of liquid lead (Pb) inclusions at grain boundaries in aluminum
(Al) was investigated by direct in situ TEM observation in the temperature range
from 330 degrees-643 degreesC. In agreement with earlier reports on quenched
alloys, the characteristic contact angle of the lens-shaped grain boundary
inclusions was found to be near 120 degrees. This angle remained approximately
constant over the entire temperature range, ruling out the possibility of a
wetting transition. Coarsening of grain boundary inclusions was observed to
proceed mainly by Ostwald ripening, although coalescence could also be observed.
Inclusions at grain boundaries, at triple junctions, and at the intersection of
grain boundaries with the foil surfaces adopted characteristic shapes that were
shown to be equilibrium forms. At the highest temperatures, the grain boundaries
were observed to detach from the inclusions and the interaction of a migrating
grain boundary with inclusions could be observed.
PMID- 9767667
TI - In Situ Studies of the Interaction of Dislocations with Point Defects during
Annealing of Ion Implanted Si/SiGe/Si (001) Heterostructures.
AB - : Strained layer heterostructures provide ideal systems with which to study the
dynamics of dislocation motion via in situ transmission electron microscopy, as
the geometry, strain state, and kinetics can be characterized and directly
controlled. We discuss how these structures are used to study dislocation-point
defect interactions, emphasizing the experimental requirements necessary for
quantification of dislocation motion. Following ion implantation, different
concentrations and types of point defects are introduced within the SiGe epilayer
depending on the implantation species, energy, and current density. By annealing
samples in situ in the transmission electron microscope (TEM) following
implantation, we can directly observe dislocation motion and quantify the effect
of dislocation-point defect interactions on dislocation velocities. We find that
dislocation motion is impeded if the implantation dose peak lies within the
epilayer, as dislocations pin at point defect atmospheres. Shallow BF2
implantation into the sample capping layer results in more complicated behavior.
For low current density implants, dislocation velocities may be dramatically
increased; at higher current densities the magnitude of this increase is
significantly smaller. Implantation of different ions separately implicates
fluorine as the species responsible for the observed increases in dislocation
velocities, presumably due to an electrical effect on the rate of dislocation
kink nucleation.
PMID- 9767668
TI - Applications of Ion Microscopy and In Situ Electron Microscopy to the Study of
Electronic Materials and Devices.
AB - : We discuss the application of ion microscopy and in situ electron microscopy to
the study of electronic and optical materials and devices. We demonstrate how the
combination of in situ transmission electron microscopy and focused ion beam
microscopy provides new avenues for the study for such structures, enabling
extension of these techniques to the study of dopant distributions, nanoscale
stresses, three-dimensional structural and chemical reconstruction, and real-time
evolution of defect microstructure. We also discuss in situ applications of
thermal, mechanical, electrical, and optical stresses during transmission
electron microscopy imaging.
PMID- 9767669
TI - In Situ Transmission Electron Microscopy Observations of Silicidation Processes
for Cobalt Thin Films Deposited on Silicon.
AB - : Morphological evolution associated with silicidation of Co thin films deposited
on (100) and (111) Si substrates has been followed using transmission electron
microscopy with in situ thermal annealing from ambient temperature up to 850
degreesC. Noticeable structural changes associated with the formation of CoSi2
occur at temperatures as low as 400 degreesC and the reaction is essentially
complete at about 500 degreesC. Prolonged heating above 500 degreesC leads to
CoSi2 grain growth and coalescence and, finally, to pinholes formation.
Silicidation of Co films on (100) and (111) Si substrates follows the same
pattern. The morphology of films annealed in situ is similar to those annealed ex
situ except that the Si/CoSi2 interface appears to be much rougher. This behavior
is associated with the specific geometry of cross-sectional TEM specimens, where
surface diffusion dominates bulk diffusion. Very thin Co films, which have less
contribution from surface diffusion than thicker films, are ideal for studying
dynamic phenomena at Co/Si reactive interfaces.
PMID- 9767670
TI - In Situ Transmission Electron Microscopy Studies of the Magnetization Reversal
Mechanism in Information Storage Materials.
AB - : The Foucault and Fresnel modes of Lorentz microscopy, together with a
quantitative magnetization mapping technique, summed image differential phase
contrast imaging, were used to study the magnetization reversal mechanism of the
sense layer in spin-valve structures exhibiting the giant magnetoresistance
effect. In addition to studies of sheet film, lithographically defined spin-valve
elements were investigated. A current can be passed through the element during
magnetizing so that the effect of the applied current on the giant
magnetoresistance and magnetization reversal mechanism can be studied. Results
are presented for a number of different spin-valve structures.
PMID- 9767672
TI - News and Commentary.
PMID- 9767671
TI - Surface Reconstruction and Oxide Nucleation Due to Oxygen Interaction with
Cu(001) Observed by In Situ Ultra-High Vacuum Transmission Electron Microscopy.
AB - : Reconstruction of the Cu(001) surface due to oxygen gas impingement on a clean
copper surface was directly observed by in situ UHV-TEM. Strain contrast between
differently oriented surface reconstruction domains, assumed to be radical2 x 2
radical2 R45, were clearly visible by this method. The reconstruction precedes
the nucleation of Cu2O islands. When Cu2O islands were partially reduced and then
re-oxidized, a dwell time before formation of Cu2O was noted, demonstrating that
a reconstructed Cu-O surface monolayer is necessary before oxide formation.
PMID- 9767673
TI - Integrin signaling: tyrosine phosphorylation events in focal adhesions.
PMID- 9767675
TI - Charge displacements in interfacial layers containing reaction centers.
AB - Reaction centers from the photosynthetic bacterium Rhodobacter sphaeroides were
oriented in phospholipid interfacial layers adsorbed to a Teflon film separating
two electrolyte-filled compartments of a Teflon cell. Light-induced voltage
changes were measured as a function of time across electrodes immersed in the
cell compartments. The experimental system is characterized both experimentally
and theoretically to relate the measured signals to the light-induced
displacement currents in the reaction centers. Mathematical relations between the
measured signals and the distances and geometries of the charge-transfer
reactions are derived. At pH 8.0 the reaction centers were found to be oriented
with approximately 60% of the population oriented with the donor facing the
aqueous phase. The density of the reaction centers in the layer was approximately
10(11) cm-2, which is close to that found in the native system. Reconstitution of
the secondary quinone, QB, in 90% of the RCs was achieved with an approximately
100-fold excess of ubiquinone in the vesicle preparation.
PMID- 9767674
TI - Blood-brain barrier permeation: molecular parameters governing passive diffusion.
AB - 53 compounds with clinically established ability to cross or not to cross the
blood-brain barrier by passive diffusion were characterized by means of surface
activity measurements in terms of three parameters, i.e., the air-water partition
coefficient, Kaw, the critical micelle concentration, CMCD, and the cross
sectional area, AD. A three-dimensional plot in which the surface area, AD, is
plotted as a function of K-1aw and CMCD shows essentially three groups of
compounds: (i) very hydrophobic compounds with large air-water partition
coefficients and large cross-sectional areas, AD > 80 A2 which do not cross the
blood-brain barrier, (ii) compounds with lower air-water partition coefficients
and an average cross-sectional area, AD congruent with 50 A2 which easily cross
the blood-brain barrier, and (iii) hydrophilic compounds with low air-water
partition coefficients (AD < 50 A2) which cross the blood-brain barrier only if
applied at high concentrations. It was shown that the lipid membrane-water
partition coefficient, Klw, measured previously, can be correlated with the air
water partition coefficient if the additional work against the internal lateral
bilayer pressure, pibi = 34 +/- 4 mN/m is taken into account. The partitioning
into anisotropic lipid membranes decreases exponentially with increasing cross
sectional areas, AD, according to Klw = const. Kaw exp(-ADpibi/kT) where kT is
the thermal energy. The cross-sectional area of the molecule oriented at a
hydrophilic-hydrophobic interface is thus the main determinant for membrane
permeation provided the molecule is surface active and has a pKa > 4 for acids
and a pKa < 10 for bases.
PMID- 9767676
TI - Nitric oxide inhibition of the rat olfactory cyclic nucleotide-gated cation
channel.
AB - The effects of nitric oxide (NO) and other cysteine modifying agents were
examined on cyclic nucleotide-gated (CNG) cation channels from rat olfactory
receptor neurons. The NO compounds, S-nitroso-cysteine (SNC) and 3-morpholino
sydnonomine (SIN-1), did not activate the channels when applied for up to 10 min.
The cysteine alkylating agent, N-ethylmaleimide (NEM), and the oxidising agent,
dithionitrobensoate (DTNB), were also without agonist efficacy. Neither SNC nor
DTNB altered the cAMP sensitivity of the channels. However, 2-min applications of
SIN-1, SNC and DTNB inhibited the cAMP-gated current to approximately 50% of the
control current level. This inhibition showed no spontaneous reversal for 5 min
but was completely reversed by a 2-min exposure to DTT. The presence of cAMP
protected the channels against NO-induced inhibition. These results indicate that
inhibition is caused by S-nitrosylation of neighboring sulfhydryl groups leading
to sulfhydryl bond formation. This reaction is favored in the closed channel
state. Since recombinantly expressed rat olfactory alpha and beta CNG channel
homomers and alpha/beta heteromers are activated and not inhibited by cysteine
modification, the results of this study imply the existence of a novel subunit or
tightly bound factor which dominates the effect of cysteine modification in the
native channels. As CNG channels provide a pathway for calcum influx, the results
may also have important implications for the physiological role of NO in
mammalian olfactory receptor neurons.
PMID- 9767677
TI - Simple carrier kinetics in complex membrane transporters.
AB - The four-state simple carrier model (SCM) has been employed to describe
facilitative transport of ligands across biological membranes. Two basic
mechanisms have been invoked to account for carrier-mediated ligand
translocation: (i) binding to a mobile carrier, and (ii) displacement determined
by conformational changes of an integral protein. While translatory carriers may
be accurately represented by a four-state diagram, it is unlikely that the
transport process mediated by a complex membrane protein can be strictly
described by the elementary SCM. The purpose of this article is to test whether
facilitative transporters with a more complex kinetic design than the SCM can
exhibit macroscopic kinetic properties indistinguishable from it. For this, I
studied a "general carrier model" (GCM), and evaluated whether the relevant
kinetic parameters are subject to the same basic restrictions as in the SCM. The
fundamental finding is that there is a general kinetic design embodied with SCM
like properties, that can be shared by many transporters. In particular, the
classical SCM is shown here to represent a particular case of the GCM. A main
conclusion of this work is therefore that the finding of a macroscopic SCM-like
kinetic behavior for a particular process of facilitative transport does not
represent a sufficient argument in favor of a particular type of mechanism, like
the typical one involving a two-conformational single-site carrier.
PMID- 9767678
TI - Freeze-fracture analysis of plasma membranes of CHO cells stably expressing
aquaporins 1-5.
AB - Several studies suggest that aquaporin water channels can be identified in
membranes by freeze-fracture electron microscopy. For this report, Chinese
Hamster ovary cells were stably transfected with cDNAs encoding aquaporins 1-5.
Measurement of the osmotic water permeability of the cells confirmed that
functional protein was expressed and delivered to the plasma membrane. By freeze
fracture electron microscopy, a 20% increase in intramembrane particle (IMP)
density was found in plasma membranes of cells expressing AQP2, 3 and 5, and a
100% increase was measured in AQP1-expressing cells, when compared to mock
transfected cells. On membranes of cells expressing AQP4, large aggregates of
IMPs were organized into orthogonal arrays, which occupied 10-20% of the membrane
surface. IMP aggregates were never seen in AQP2-transfected cells. Hexagonally
packed IMP clusters were detected in approximately 5% of the membranes from AQP3
expressing cells. Particle size-distribution analysis of rotary shadowed IMPs
showed a significant shift from 13. 5 (control cells) to 8.5 nm or less in AQP
expressing cells; size distribution analysis of unidirectionally shadowed IMPs
also showed a significant change when compared to control. Some IMPs in AQP
expressing cells had features consistent with the idea that aquaporins are
assembled as tetramers. The results demonstrate that in transfected CHO cells,
AQP transfection modifies the general appearance and number of IMPs on the plasma
membrane, and show that only AQP4 assembles into well-defined IMP arrays.
PMID- 9767679
TI - Biophysical characteristics of swelling-activated Cl- channels in human tracheal
9HTEo-cells.
AB - The question of whether a single molecule can account for every observed swelling
activated Cl- current deserves to be addressed and biophysical description seems
to be an adequate criterion to classify these channels. We studied the
biophysical properties of swelling-activated Cl- currents in 9HTEo-cells using
whole-cell and outside-out patch clamp recordings. Hypotonic shock activated
outwardly rectifying currents that inactivated at potentials higher than 20 mV.
The decay phase of the current was well fitted by two exponential functions and
both time constants were voltage-dependent. Two voltage-dependent time constants
were also necessary to describe reactivation. The midpoint of current
inactivation was 54 mV. The voltage dependence of kinetics did not significantly
change by modifying the extracellular NaCl concentration while the inactivation
midpoint slightly shifted. In conclusion, our results indicate that the voltage
dependent properties of the swelling-activated Cl- currents in 9HTEo- cells are
largely independent from the extracellular ionic strength and the extracellular
Cl- concentration. Excised patches from cells exposed to hypotonic shock showed
single channel currents that inactivated at positive membrane potentials and
displayed chord conductance of approximately 60 pS at 100 mV and of approximately
20 pS at -80 mV. The permeability sequence for the single channel was I- > Br- >
Cl- > gluconate and currents were blocked by Reactive blue 2. These properties
indicate that intermediate conductance outwardly rectifying channels are
responsible for the macroscopic swelling-activated current.
PMID- 9767680
TI - Characterization of the Na+/H+ exchanger in the luminal membrane of the distal
nephron.
AB - In the rabbit as well as the rat, a Na+/H+ exchanger is expressed in the apical
membrane of both the proximal and distal tubules of the renal cortex. Whereas the
isoform derived from the proximal tubule has been extensively studied, little
information is available concerning the distal luminal membrane isoform. To
better characterize the latter isoform, we purified rabbit proximal and distal
tubules, and examined the ethylpropylamiloride (EIPA)-sensitive 22Na uptake by
the luminal membrane vesicles from the two segments. The presence of 100 micron
EIPA in the membrane suspension decreased the 15 sec Na+ uptake to 75.70 +/-
4.70% and 50.30 +/- 2.23% of the control values in vesicles from proximal and
distal tubules, respectively. The effect of EIPA on 35 mM Na+ uptake was
concentration dependent, with a IC50 of 700 micron and 75 micron for the proximal
and distal luminal membranes. Whereas the proximal tubule membrane isoform was
insensitive to cimetidine and clonidine up to a concentration of 2 mM, the 35 mM
Na+ uptake by the distal membrane was strongly inhibited by cimetidine (IC50 700
micron) and modestly inhibited by clonidine (IC50 1.6 mM). The incubation of
proximal tubule suspensions with 1 mM (Bu2) cAMP decreased the 15-sec EIPA
sensitive Na+ uptake by the brush border membranes to 24.1 +/- 2.38% of the
control values. Unexpectedly, the same treatment of distal tubules enhanced this
uptake by 46.5 +/- 10.3%. Finally, incubation of tubule suspensions with 100 nm
phorbol 12-myristate 13-acetate (PMA) decreased the exchanger activity to 58.6 +/
3.04% and 79.7 +/- 3.21% of the control values in the proximal and distal
luminal membranes, respectively. In conclusion, the high sensitivity of the
distal luminal membrane exchanger to various inhibitors, and its stimulation by
cAMP-dependent protein kinase A, indicate that this isoform differs from that of
the proximal tubule and probably corresponds to isoform 1.
PMID- 9767681
TI - Na+-coupled alanine transport in LLC-PK1 cells: the relationship between the Km
for Na+ at low [Alanine] and potential dependence for the system.
AB - Analysis of the mechanistic basis by which sodium-coupled transport systems
respond to changes in membrane potential is inherently complex. Algebraic
expressions for the primary kinetic parameters (Km and Vmax) consist of multiple
terms that encompass most rate constants in the transport cycle. Even for a
relatively simple cotransport system such as the Na+/alanine cotransporter in LLC
PK1 cells (1:1 Na+ to substrate coupling, and an ordered binding sequence), the
algebraic expressions for Km for either substrate includes ten of the twelve rate
constants necessary for modeling the full transport cycle. We show here that the
expression of Km of the first-bound substrate (Na+) simplifies markedly if the
second-bound substrate (alanine) is held at a low concentration so that its'
binding becomes the rate limiting step. Under these conditions, the expression
for the KNam includes rate constants for only two steps in the full cycle: (i)
binding/dissociation of Na+, and (ii) conformational 'translocation' of the
substrate-free protein. The influence of imposed changes in membrane potential on
the apparent KNam for the LLC-PK1 alanine cotransporter at low alanine thus
provides insight to potential dependence at these sites. The data show no
potential dependence for KNam at 5 micron alanine, despite marked potential
dependence at 2 mm alanine when the full algebraic expression applies. The
results suggest that neither translocation of the substrate-free form of the
transporter nor binding/dissociation of extracellular sodium are potential
dependent events for this transport system.
PMID- 9767682
TI - Site-specific prebiotic oligomerization reactions of glycine on the surface of
hectorite.
AB - Condensation reactions of the amino acid glycine on the surface of Cu(II)
exchanged hectorite are investigated using the technique of scanning force
microscopy. Prebiotic conditions are simulated using alternate wetting and
heating cycles. Concentration, immobilization, and subsequent polymerization
resulting in glycine oligomers are seen to occur primarily at step edges or
faults in the topmost layer. Condensation reactions also occur within tiny
micropores or defects in the topmost layer. These reactions are facilitated by
the availability of intergallery metal cations at the step edges or pores in the
surface region.
PMID- 9767684
TI - Biased usages of arginines and lysines in proteins are correlated with local
scale fluctuations of the G + C content of DNA sequences.
AB - Amino acid residues arginine (R) and lysine (K) have similar physicochemical
characteristics and are often mutually substituted during evolution without
affecting protein function. Statistical examinations on human proteins show that
more R than K residues are used in the proximity of R residues, whereas more K
than R are used near K residues. This biased use occurs on both a global and a
local scale (shorter than approximately 100 residues). Even within a given exon,
G + C-rich and A + T-rich short DNA segments preferentially encode R and K,
respectively. The biased use of R and K on a local scale is also seen in
Saccharomyces cerevisiae and Caenorhabdidtis elegans, which lack global-scale
mosaic structures with varying GC%, or isochores. Besides R and K, several amino
acids are also used with a positive or negative correlation with the local GC% of
third codon bases. The local-, or "within-gene"-, scale heterogeneity of the DNA
sequence may influence the sequence of the encoded protein segment.
PMID- 9767683
TI - Directionally evolving genetic code: the UGA codon from stop to tryptophan in
mitochondria.
AB - For the comprehensive analyses of deviant codes in protistan mitochondria (mt),
we sequenced about a 1.1-kb region of a mitochondrial (mt) gene, the cytochrome c
oxidase subunit I (coxI) in two chlorarachniophytes, the filose amoeba Euglypha
rotunda, the cryptomonad Cryptomonas ovata, the prymnesiophyte (haptophyte)
Diacronema vlkianum (Pavlovales), and the diatom Melosira ambigua. As a result of
this analysis, we noticed that the UGA codon is assigned to tryptophan (Trp)
instead of being a signal for translational termination in two
chlorarachniophytes and in E. rotunda. The same type of deviant code was reported
previously in animals, fungi, ciliates, kinetoplastids, Chondrus crispus (a red
alga), Acanthamoeba castellanii (an amoeboid protozoon), and three of the four
prymnesiophyte orders with the exception of the Pavlovales. A phylogenetic
analysis based on the COXI sequences of 56 eukaryotes indicated that the
organisms bearing the modified code, UGA for Trp, are not monophyletic. Based on
these studies, we propose that the ancestral mitochondrion was bearing the
universal genetic code and subsequently reassigned the codon to Trp
independently, at least in the lineage of ciliates, kinetoplastids, rhodophytes,
prymnesiophytes, and fungi. We also discuss how this codon was directionally
captured by Trp tRNA.
PMID- 9767685
TI - Limitations of metazoan 18S rRNA sequence data: implications for reconstructing a
phylogeny of the animal kingdom and inferring the reality of the Cambrian
explosion.
AB - We document the phylogenetic behavior of the 18S rRNA molecule in 67 taxa from 28
metazoan phyla and assess the effects of among-site rate variation on
reconstructing phylogenies of the animal kingdom. This empirical assessment was
undertaken to clarify further the limits of resolution of the 18S rRNA gene as a
phylogenetic marker and to address the question of whether 18S rRNA phylogenies
can be used as a source of evidence to infer the reality of a Cambrian explosion.
A notable degree of among-site rate variation exists between different regions of
the 18S rRNA molecule, as well as within all classes of secondary structure.
There is a significant negative correlation between inferred number of nucleotide
substitutions and phylogenetic information, as well as with the degree of
substitutional saturation within the molecule. Base compositional differences
both within and between taxa exist and, in certain lineages, may be associated
with long branches and phylogenetic position. Importantly, excluding sites with
different degrees of nucleotide substitution significantly influences the
topology and degree of resolution of maximum-parsimony phylogenies as well as
neighbor-joining phylogenies (corrected and uncorrected for among-site rate
variation) reconstructed at the metazoan scale. Together, these data indicate
that the 18S rRNA molecule is an unsuitable candidate for reconstructing the
evolutionary history of all metazoan phyla, and that the polytomies, i.e.,
unresolved nodes within 18S rRNA phylogenies, cannot be used as a single or
reliable source of evidence to support the hypothesis of a Cambrian explosion.
PMID- 9767686
TI - Trematode and monogenean rRNA ITS2 secondary structures support a four-domain
model.
AB - The secondary structure of rRNA internal transcribed spacer 2 is important in the
process of ribosomal biogenesis. Trematode ITS sequences are poorly conserved and
difficult to align for phylogenetic comparisons above a family level. If a
conserved secondary structure can be identified, it can be used to guide primary
sequence alignments. ITS2 sequences from 39 species were compared. These species
span four orders of trematodes (Echinostomiformes, Plagiorchiformes,
Strigeiformes, and Paramphistomiformes) and one monogenean (Gyrodactyliformes).
The sequences vary in length from 251 to 431 bases, with an average GC content of
48%. The monogenean sequence could not be aligned with confidence to the
trematodes. Above the family level trematode sequences were alignable from the 5'
end for 139 bases. Secondary structure foldings predicted a four-domain model.
Three folding patterns were required for the apex of domain B. The folding
pattern of domains C and D varies for each family. The structures display a high
GC content within stems. Bases A and U are favored in unpaired regions and
variable sites cluster. This produces a mosaic of conserved and variable regions
with a structural conformation resistant to change. Two conserved strings were
identified, one in domain B and the other in domain C. The first site can be
aligned to a processing site identified in yeast and rat. The second site has
been found in plants, and structural location appears to be important. A
phylogenetic tree of the trematode sequences, aligned with the aid of secondary
structures, distinguishes the four recognized orders.
PMID- 9767687
TI - Phylogenetic position of the Phacotaceae within the Chlamydophyceaeas revealed by
analysis of 18S rDNA and rbcL sequences.
AB - Four genera of the Phacotaceae (Phacotus, Pteromonas, Wislouchiella,
Dysmorphococcus), a family of loricated green algal flagellates within the
Volvocales, were investigated by means of transmission electron microscopy and
analysis of the nuclear encoded small-subunit ribosomal RNA (18S rRNA) genes and
the plastid-encoded rbcL genes. Additionally, the 18S rDNA of Haematococcus
pluvialis and the rbcL sequences of Chlorogonium elongatum, C. euchlorum,
Dunaliella parva, Chloromonas serbinowii, Chlamydomonas radiata, and C. tetragama
were determined. Analysis of ultrastructural data justified the separation of the
Phacotaceae into two groups. Phacotus, Pteromonas, and Wislouchiella generally
shared the following characters: egg-shaped protoplasts, a single pyrenoid with
planar thylakoid double-lamellae, three-layered lorica, flagellar channels as
part of the central lorica layer, mitochondria located in the central cytoplasm,
lorica development that occurs in mucilaginous zoosporangia that are to be lysed,
and no acid-resistant cell walls. Dysmorphococcus was clearly different in each
of the characters mentioned. Direct comparison of sequences of Phacotus
lenticularis, Pteromonas sp., Pteromonas protracta, and Wislouchiella planctonica
revealed DNA sequence homologies of >/=98. 0% within the 18S gene and 93.9%
within the rbcL gene. D. globosus was quite different from these species, with a
maximum of 92.9% homology in the 18S rRNA and =86.6% in the rbcL gene. It
showed major similarities to the 18S rDNA of Dunaliella salina, with 95.3%, and
to the rbcL sequence of Chlamydomonas tetragama, with 90.3% sequence homology.
Additionally, the Phacotaceae sensu stricto exclusively shared 10 (rbcL: 4)
characters which were present neither in other Chlamydomonadales nor in
Dysmorphococcus globosus. Different phylogenetic analysis methods confirmed the
hypothesis that the Phacotaceae are polyphyletic. The Phacotaceae sensu stricto
form a stable cluster with affinities to the Dunaliellaes and possibly
Haematococcus pluvialis. Dysmorphococcus globosus represented an independent
lineage that is possibly related to Chlamydomonas moewusii and C. tetragama.
PMID- 9767688
TI - The mitochondrial genome of Chlorogonium elongatum inferred from the complete
sequence.
AB - The 22,704-bp circular mitochondrial DNA (mtDNA) of the chlamydomonad alga
Chlorogonium elongatum was completely cloned and sequenced. The genome encodes
seven proteins of the respiratory electron transport chain, subunit 1 of the
cytochrome oxidase complex (cox1), apocytochrome b (cob), five subunits of the
NADH dehydrogenase complex (nad1, nad2, nad4, nad5, and nad6), a set of three
tRNAs (Q, W, M), and the large (LSU)- and small (SSU)-subunit ribosomal RNAs. Six
group-I introns were found, two each in the cox1, cob, and nad5 genes. In each
intron an open reading frame (ORF) related to maturases or endonucleases was
identified. Both the LSU and the SSU rRNA genes are split into fragments
intermingled with each other and with other genes. Although the average A + T
content is 62.2%, GC-rich clusters were detected in intergenic regions, in
variable domains of the rRNA genes, and in introns and intron-encoded ORFs. A
comparison of the genome maps reveals that C. elongatum and Chlamydomonas
eugametos mtDNAs are more closely related to one another than either is to
Chlamydomonas reinhardtii mtDNA.
PMID- 9767689
TI - The complete mitochondrial DNA sequence of the domestic sheep (Ovis aries) and
comparison with the other major ovine haplotype.
AB - The complete mitochondrial DNA (mtDNA) molecule of the domestic sheep, Ovis
aries, was sequenced, together with part of the mtDNA of a specimen representing
the other major O. aries haplotype group. The length of the complete ovine mtDNA
presented is 16,616 nucleotides (nt). This length is not absolute, however, due
to heteroplasmy caused by the occurrence of different numbers of a 75-nt-long
tandem repeat in the control region. The sequence data were included in analyses
of intraspecific ovine molecular differences, molecular comparisons with bovine
mtDNAs, and phylogenetic analyses based on complete mtDNAs. The comparisons with
bovine mtDNAs were based on the central domains of the ovine control regions,
representing both major ovine haplotype groups, and the corresponding domains of
Bos taurus and B. indicus. The comparisons showed that the difference between the
bovids was 1.4 times greater than the intraspecific ovine difference. These
findings suggest that the strains of wild sheep from which domestic sheep
originated were more closely related than were the B. primigenius subspecies
which gave rise to B. indicus and B. taurus cattle. Datings based on complete
mtDNAs suggest that the bovine and ovine lineages diverged about 30 million years
before present. This dating is considerably earlier than that proposed
previously.
PMID- 9767690
TI - Organization and evolution of the mitochondrial DNA control region in the avian
genus Alectoris.
AB - The entire mitochondrial DNA control region (mtDNA D-loop) was sequenced in the
seven extant species of Alectoris partridges. The D-loop length is very conserved
(1155 +/- 2 nucleotides), and substitution rates are lower than for the
mitochondrial cytochrome b gene of the same species, on average. Comparative
analyses suggest that these D-loops can be divided into three domains,
corresponding to the highly variable peripheral domains I and III and to the
central conserved domain II of vertebrates (Baker and Marshall 1997).
Nevertheless, the first 161 nucleotides of domain I of the Alectoris, immediately
flanking the tRNAGlu, evolve at an unusually low rate and show motifs similar to
the mammalian extended termination-associated sequences [ETAS1 and ETAS2 (Sbisa
et al. 1997)], which can form stable secondary structures. The second part of
domain I contains a hypervariable region with two divergent copies of a tandemly
repeated sequence described previously in other species of anseriforms and
galliforms (Quinn and Wilson 1993; Fumihito et al. 1995). Some of the conserved
sequence blocks of mammals can be mapped in the central domain of Alectoris.
Domain III is highly variable and has sequences similar to mammalian CSB1. The
bidirectional transcription promoter HSP/LSP box of the chicken is partially
conserved among the Alectoris. This structural organization can be found in the
anseriform and galliform species studied so far, suggesting that strong
functional constraints might have controlled the evolution of the D-loop since
the origin of Galloanserae. Their conserved organization and slow molecular
evolution make D-loops of galliforms appropriate for phylogenetic studies,
although homoplasy can be be generated at a few hypervariable sites and at some
sites which probably have mutated by strand slippage during DNA replication.
Phylogenetic analyses of D-loops of Alectoris are concordant with previously
published cytochrome b and allozyme phylogenies (Randi 1996). Alectoris is
monophyletic and includes three major clades: (1) basal barbara and
melanocephala; (2) intermediate rufa and graeca; and (3) recent philbyi, magna,
and chukar. Comparative description of the organization and substitution patterns
of the mitochondrial control region can aid in mapping hypervariable sites and
avoid some sources of homoplasy in data sets which are to be used in phylogenetic
analyses.
PMID- 9767691
TI - Similar target site selection occurs in integration of plant and mammalian
retroposons.
AB - The reverse transcription of RNA in DNA is responsible for the generation of
large families of repetitive sequences called retroposons or non-LTR
retrotransposons. Recent reports established that the integration of mammalian
SINE and LINE retroposons occurs at nonrandom staggered breaks, probably
resulting from the action of a LINE-encoded endonuclease (Feng et al. 1996; Jurka
1997; Jurka et al. 1998). We report here that plant SINE S1 retroposons also
integrate at nonrandom staggered breaks. One of the two nicks involved in S1
integration is associated mainly with the 5'-Y/AAANNNG-3' motif. The other nick
at opposite DNA strand occurs preferably within 14-16 bp, a situation also
observed for mammalian retroposons, but is not associated with any specific
motif. Further studies on the distribution of dinucleotides surrounding the two
nicking sites showed that, as for mammalian retroposons, S1 retroposons integrate
at sites rich in TA, CA, and TG dinucleotides. These dinucleotides were reported
as specific DNA sites where special DNA structures called "kinks" may occur under
bending constraints. Nicking sites are preceded by peaks in frequency of di
pyrimidine followed by peaks of di-purine. These results suggest that the general
A/T richness of a given DNA region and the presence of short runs of pyrimidines
followed by short runs of purines could represent a favorable context for the
integration of retroposons. In such a context, an endonuclease upon fixation
could be able to generate the kink at the pyrimidine/purine transition and to
nick the DNA. The similarities in target site selection observed for plant and
mammalian retroposons suggest that retroposition is a surprisingly well conserved
process.
PMID- 9767692
TI - Phylogenetic analysis of reptilian hemoglobins: trees, rates, and divergences.
AB - Phylogenetic relationships among reptiles were examined using previously
published and newly determined hemoglobin sequences. Trees reconstructed from
these sequences using maximum-parsimony, neighbor-joining, and maximum-likelihood
algorithms were compared with a phylogenetic tree of Amniota, which was assembled
on the basis of published morphological data. All analyses differentiated alpha
chains into alphaA and alphaD types, which are present in all reptiles except
crocodiles, where only alphaA chains are expressed. The occurrence of the alphaD
chain in squamates (lizards and snakes only in this study) appears to be a
general characteristic of these species. Lizards and snakes also express two
types of beta chains (betaI and betaII), while only one type of beta chain is
present in birds and crocodiles. Reconstructed hemoglobin trees for both alpha
and beta sequences did not yield the monophyletic Archosauria (i.e., crocodilians
+ birds) and Lepidosauria (i.e., Sphenodon + squamates) groups defined by the
morphology tree. This discrepancy, as well as some other poorly resolved nodes,
might be due to substantial heterogeneity in evolutionary rates among single
hemoglobin lineages. Estimation of branch lengths based on uncorrected amino acid
substitutions and on distances corrected for multiple substitutions (PAM
distances) revealed that relative rates for squamate alphaA and alphaD chains and
crocodilian beta chains are at least twice as high as those of the rest of the
chains considered. In contrast to these rate inequalities between reptilian
orders, little variation was found within squamates, which allowed determination
of absolute evolutionary rates for this subset of hemoglobins. Rate estimates for
hemoglobins of lizards and snakes yielded 1.7 (alphaA) and 3.3 (beta) million
years/PAM when calibrated with published divergence time vs. PAM distance
correlates for several speciation events within snakes and for the squamate left
and right arrow sphenodontid split. This suggests that hemoglobin chains of
squamate reptiles evolved approximately 3.5 (alphaA) or approximately 1.7 times
(beta) faster than their mammalian equivalents. These data also were used to
obtain a first estimate of some intrasquamate divergence times.
PMID- 9767693
TI - Sequence peculiarity of gnetalean legumin-like seed storage proteins.
AB - The development of seeds as a specialized organ for the nutrition, protection,
and dispersal of the next generation was an important step in the evolution of
land plants. Seed maturation is accompanied by massive synthesis of storage
compounds such as proteins, starch, and lipids. To study the processes of seed
storage protein evolution we have partially sequenced storage proteins from
maturing seeds of representatives from the gymnosperm genera Gnetum, Ephedra, and
Welwitschia-morphologically diverse and unusual taxa that are grouped in most
formal systems into the common order Gnetales. Based on partial N-terminal amino
acid sequences, oligonucleotide primers were derived and used for PCR
amplification and cloning of the corresponding cDNAs. We also describe the
structure of the nuclear gene for legumin of Welwitschia mirabilis. This first
gnetalean nuclear gene structure contains introns in only two of the four
conserved positions previously characterized in other spermatophyte legumin
genes. The distinct phylogenetic status of the gnetalean taxa is also reflected
in a sequence peculiarity of their legumin genes. A comparative analysis of
exon/intron sequences leads to the hypothesis that legumin genes from Gnetales
belong to a monophyletic evolutionary branch clearly distinct from that of
legumin genes of extant Ginkgoales and Coniferales as well as from all
angiosperms.
PMID- 9767694
TI - Sensitivity of patterns of molecular evolution to alterations in methodology: a
critique of Hughes and Yeager.
AB - Employing a set of 43 othologous mouse and rat genes, Hughes and Yeager (J. Mol.
Evol. 45:125-130, 1997) reported (1) no correlation between synonymous and
nonsynonymous rates of nucleotide substitution, (2) a positive correlation
between intronic GC contents (GCi) and intronic substitution rates (Ki), (3) that
the average Ki value was very similar to the average Ks value, and (4) that the
compositional correlation between the rat and the mouse genes is stronger at the
third codon position (GC3) than at the first and second codon positions (GC12).
We have examined the robustness of these results to alterations in substitution
rate estimation protocol, alignment protocol, and statistical procedure. We find
that a significant correlation between Ka and Ks is observed either if a rank
correlation statistic is used instead of regression analysis, if one outlier is
excluded from the analysis, or if a regression weighted by gene size is employed.
The correlation between Ki and GCi we find to be sensitive to changes in
alignment protocol and disappears on the use of weighted means. The finding that
Ks and Ki are approximately the same is dependent on the method for estimating Ks
values. Finally, the variance around the regression line of rat GC3 versus mouse
GC3 we find to be significantly higher than that in GC12. The source of the
discrepancy between this and Hughes and Yeager's result is unclear. The variance
around the line for GC4 is higher still, as might be expected. Using a
methodology that may be considered preferable to that of Hughes and Yeager, we
find that all four of their results are contradicted. More importantly this
analysis reinforces the need for caution in assembling and analyzing data sets,
as the degree of sensitivity to what many might consider minor methodological
alterations is unexpected.
PMID- 9767695
TI - Midiabdominoplasty: indications and technique.
AB - In the treatment of aesthetic deformities of the abdomen there are three points
we should analyze: the skin, the fat tissue, and the muscles. Based on these
points we can classify it into six groups. Midiabdominoplasty is indicated in the
correction of deformities of groups 2, 3, and 4. A small fusiform resection of
skin is done in the lower abdomen, undermining of the skin up to the umbilicus
(or to the xiphoid appendix if necessary to treat diastasis of the rectus muscles
in the supraumbilical region), and desinsertion of the umbilicus, with no
external scar, are the main points in this technique. The main complication was
the formation of seroma. No necrosis of the flap or unsightly scars were
observed. The results were good, with the patients satisfied with their new
abdomens.
PMID- 9767696
TI - High-tech facelift.
AB - Recent technological advances in our specialty have made us reappraise the way we
approach facial rejuvenation. Some of these technological interfaces have made it
possible, in the author's experience, to improve results and to tackle difficult
aesthetic problems. The purpose of this paper is to report how we combine these
technological advances in an effort to improve the aesthetic outcomes. These
technological advances are: laser skin resurfacing, endoscopy, newer fat grafting
procedures, and new alloplastic materials for bone augmentation. Other
technological advances are consultations via the Internet, computer imaging for
simulation of possible outcomes, etc. Endoscopy is routinely used in our facial
rejuvenative procedures, almost always for the forehead, often for the midface
and less often for the neck. Fat grafting procedures using newly adapted concepts
are used for the brow, glabella, tear trough deformity, cheeks, lips, chin,
nasolabial folds, marionette lines, and other areas of soft tissue depressions
apparent before or after the lifting procedures. This has allowed us to restore
the tridimensional volume and treat the soft tissue atrophy. Patients with
significant skeletal soft tissue disproportion due to aging, loss of dentition,
prior trauma or congenital defects may receive one or more of the following
implants: glabella, cheek, piriformis, angle of the mandible, mandibular body
glove type of implant, prejawl implant, chin overlay or a glove type of implant.
Our preference is for a porous polyethylene material because of its tissue
ingrowth inductiveness. Individuals who have damaged skin due to solar exposure,
aging, smoking, etc., may receive Ultrapulse CO2 laser resurfacing at the same
operative setting (more often) or in a delayed fashion. The Versapulse laser is
also needed for the treatment of some skin changes secondary to aging such as
telangiectasias (Variable Pulse Green) and brown spots (Q-Switch 532). The high
tech facelift has allowed us to treat the severely damaged skin, fat atrophy,
bone atrophy in many patients, at the same time that the lifting procedure is
performed. This provides a more comprehensive approach to facial rejuvenation.
The combination of different techniques and technologies maximizes the
effectiveness and minimizes the potential side effects of each one. Scars in the
forehead and scalp are avoided. Incision and fat removal in the lower eyelid are
often unnecessary. It provides a more precise vertical lifting with correction of
the tear trough deformity and gives a tridimensional restoration of the facial
volume. The facial disharmony is treated at every level starting from the facial
skeletal support to the most external envelope (skin). Over 200 patients have
been treated this way with a minimal rate of complications. The high-tech facial
rejuvenation has allowed us to improve the surgical results of our patients
compared with previous isolated techniques. The combination of each one of the
techniques require a precise understanding of the limits and benefits of each.
Case examples of the different combinations will be shown.
PMID- 9767699
TI - Direct K-wire fixation technique during endoscopic brow lift.
AB - Endoscopic brow lift has now become a well-established procedure for restoring a
youthful brow. Multiple techniques have been described for fixation of the scalp;
however, these methods do not allow for direct positioning of the brow. A simple
method is described that establishes precise and direct brow fixation using K
wires. Twelve female patients underwent direct fixation of the brow with one or
more K-wires to the supraorbital rim. No complications occurred as a result of
this technique. Direct brow fixation with K-wires appears to be a simple
effective technique for precise restoration of brow position.
PMID- 9767697
TI - Body dysmorphic disorder and aesthetic surgery: case report.
AB - The appearance of psychiatric disorders among plastic surgery patients is well
known, and its frequency is higher than in other surgical branches. There is
evidence that these patients may suffer from body dysmorphic disorder (BDD), a
mental disorder characterized by excessive concern about some imaginary or slight
physical defect, causing significant clinical discomfort, social deterioration,
and losses in other important areas of the individuals' activity. We present a
typical case of BDD and discuss diagnostic criteria and the proper attitude the
plastic surgeon should adopt toward this kind of patient.
PMID- 9767698
TI - In favor of the subcutaneous forehead lift using the anterior hairline incision.
AB - We present our experience with 980 women who had subcutaneous forehead lifts
using the anterior hairline incision, during the years 1989-1996. The dissection
is easy and fast; the forehead wrinkles are smoothed by the separation of the
septa between the frontalis and the skin. The access to the corrugator and the
procerus muscles is easy, and the adjustment of the brows to the desired location
can be accurate. We use this approach for 90% of women who are eligible for upper
face rejuvenation. We have obtained a 96% satisfaction rate; only 1.8% of our
patients had minor and reversible complications. The scar, which is supposed to
be the main disadvantage of this procedure, is almost unnoticeable, and none of
our patients has permanently changed her hairstyle due to this operation. Now,
during the peak of interest in forehead lifts with limited scars using the
endoscope, is the time to highlight this time-worn, safe, reproducible, and
effective approach.
PMID- 9767700
TI - Blepharoplasty: A classification of selected techniques in the treatment and
prevention of lower lid margin distortions.
AB - In the past few years the approach to lower blepharoplasty complications has
evolved. New and worthy preventive and curative treatments have been suggested
for both scleral show and ectropion (operations with or without interruption of
the lid margin, mucosal grafts, orbicularis flaps, etc.). Among these, several
techniques have been chosen and analyzed, evaluating the advantages and
disadvantages of each.
PMID- 9767701
TI - Treatment of orbicularis oculi muscle hypertrophy in lower lid blepharoplasty.
AB - Treatment of orbicularis oculi muscle hypertrophy during conventional lower
eyelid blepharoplasty is presented. Horizontal resection of a strip of the
hypertrophic muscle is carried out, which allows flattening of the muscular bulge
in an anteroposterior direction. Since no full-thickness vertical reduction is
performed, this simple procedure is "free" from the risk of "scleral show"
deformity, due to excessive muscle shortening, leaving a pleasant contour in the
lower eyelid. The technique has been successfully employed in 27 cases of
blepharoplasty, with separate skin and muscle flaps.
PMID- 9767702
TI - One-stage reconstruction of an upper part defect of the auricle.
AB - A one-stage procedure for the reconstruction of a defect of the upper auricle is
described. The anterior surface of a carved costal cartilage graft was covered
with an anterosuperiorly based skin flap, and the posterior surface was covered
by the superficial mastoid fascial flap and a skin graft. This method can be
performed easily, without leaving any scar in the hair-bearing area or visible
postauricular region, and can be applied to cases in which the condition of the
margin scar of an auricular defect is poor.
PMID- 9767703
TI - PMMA-Microspheres (Artecoll) for long-lasting correction of wrinkles: refinements
and statistical results.
AB - The corium is diminished to about half of its thickness in skin defects and
wrinkles. All biological materials that increase the thickness of the corium are
resorbed within a certain time. Therefore, a lasting effect can be achieved only
with nonresorbable synthetic substances. Artecoll consists of microspheres of 30
40 microm in diameter, of exceptional surface smoothness, purity, and homogeneity
related to PMMA. These microspheres are suspended in atelocollagen which serves
as a vehicle for subdermal implantation. Due to its smooth surface and
consequential lack of electrical charges, each single microsphere is immediately
encapsulated with the patient's own collagen fibers, thus preventing dislocation.
Within 3 months, collagen (making up 75% of Artecoll) is replaced by the body's
own connective tissue. The microspheres (25% of Artecoll) serve merely as a
stimulus to the fibroblasts. Indications for Artecoll are all facial folds, lip-
and philtrum augmentation, chin- and malar augmentation, dark-shadowed eyelids,
enophthalmos, bony defects in face and hands, nipple reconstruction and
augmentation, and urinary incontinence. Questionnaires were sent to all patients
who had received Artecoll in 1993 and 1994. Of a total of 950 questionnaires
sent, 515 were returned by September 1995. Satisfaction was rated "very good" in
29%, "good" in 38%, "satisfactory" in 23%, and "no difference" in 8% of the
patients. The question, "Would you repeat the treatment again?" was answered by
91% of the patients with "yes." The overall complication rate was 3%. Strictly
subdermal implantation will prevent longer lasting redness or visibility of the
Artecoll.
PMID- 9767705
TI - Innovative new concepts in augmentative breast surgery.
AB - The female breast is seen as a badge of feminine beauty in our society. While it
can vary over time and with fashions, the perfect breast will always be
symmetrically balanced and proportionate to the rest of the body. To create an
aesthetic and symmetrically balanced breast using implants to enhance them is not
an easy task. Surgery must combine the concepts of an ideal breast with the
desires of the patient in terms of size. The satisfactory breast should remain
soft, well positioned, and mobile to respond to gravity and postural changes. In
attempting to construct an "ideal breast," certain basic aesthetic anatomical
proportions should be taken into account: natural positioning of the breast in
the thorax; symmetry; the position of the nipple-areola complex as the focal
point of the breast in the frontal view; a side profile of the breast with a
natural soft fall; and, overall, the position of the new inframammary crease in
the standing position, while lying down, and while moving.
PMID- 9767704
TI - Eyebrow asymmetry: ways of correction.
AB - Ocassionally a patient asks for correction of his asymmetric eyelids. In many
instances, however, a careful analysis reveals that the actual cause is an
asymmetry of the eyebrows. Generally, asymmetric eyebrows are due to excessive
muscle dynamics (i.e., a hyperkinesia of the frontalis or the depressor
supercilii muscles). Therefore, the asymmetry will not be corrected by an
asymmetric blepharoplasty, which will instead disclose the preexisting asymmetry,
much to the concern of the patient. Management of the asymmetric brow is
demanding and requires a preoperative problem-oriented and detailed analysis of
the individual patient to achieve satisfactory results. We present 10-years'
experience using a problem-specific approach. This included intramuscular
botulinum toxin A injection, superselective neurotomy, endoscopic browlift and
traditional procedures such as the coronal and direct browlift. Indication,
patient selection, results, and complications are discussed.
PMID- 9767706
TI - Technical refinements of infracture for the zygomatic body and arch reduction.
AB - Nowadays the infracture technique for the zygomatic body and arch has been
popularized in Oriental countries for the reduction of zygoma. We can obtain
sufficient operative field to handle the zygoma through the intraoral and
temporopreauricular incision and control the amount of shaving and infracturing
zygomatic prominence. We developed three types of infracture technique for the
reduction of the zygomatic body and arch according to the degree of severity of
the zygomatic prominence and the shape of the face: Type A, infracturing with
bone-to-bone contact for mild prominence with/without a long face; Type B,
infracturing beyond bone-to-bone contact for moderate prominence; and Type C,
infracturing far beyond bone-to-bone contact and microplate fixation for severe
prominence with/without a broad and short face. By applying the criteria
described above, we can obtain aesthetically acceptable results in zygoma
reduction.
PMID- 9767707
TI - Xylose transport by the anaerobic thermophile thermoanaerobacter ethanolicus and
the characterization of a D-xylose-binding protein
AB - Thermoanaerobacter ethanolicus is a xylose-utilizing thermophilic anaerobe that
produces considerable amounts of ethanol. A protein in xylose-growing cells was
solubilized from cell membranes by extraction with octyl-beta-glucoside. Internal
peptide sequencing revealed that the protein was the product of a gene, xylF,
encoding a putative D-xylose-binding protein. Metabolic labeling with 14C
palmitic acid suggested that this is a lipoprotein that is anchored to the cell
membrane via a cysteine residue. Binding was highly specific for xylose as
evident by the lack of competition by sugars with structures similar to xylose.
The apparent Kd of the protein for xylose was approximately 1.5 &mgr;M, and this
value was very similar to the affinity constant determined for xylose transport
by whole cells at low substrate concentrations. Uptake experiments with cells
also suggested the presence of a separate low-affinity system. Binding activity
varied less than 20% over a pH range of 4-8, and the level of activity was
virtually unaffected when temperature was varied between 40 degreesC and 80
degreesC. This is the first biochemical characterization of a D-xylose-binding
protein from a thermophilic organism.
PMID- 9767708
TI - Rhizobacterial glutathione levels as affected by starvation and cadmium exposure.
AB - The rhizosphere is a continuously fluctuating environment in which severe
stresses are put on its inhabitants, and glutathione, a reducing tripeptide, and
related compounds probably have important roles in cellular protection. In the
present study the metabolism of glutathione was examined in rhizobacteria
subjected to stress. The plant-growth-promoting rhizobacterium Pseudomonas
fluorescens 5.014 and its mutant 5-2/4 were exposed to starvation, either by
resuspension or exhaustion, and to cadmium. Glutathione levels, cell protein, and
viable count were determined and compared in different conditions. Both
starvation and cadmium exposure decreased the amount of glutathione in the cell.
No changes of the glutathione concentration in the medium were observed with or
without the presence of rhizobacteria, indicating that there was no transport
over the cell membrane. The glutathione levels within the rhizobacteria may give
valuable information on how different stresses affect the bacteria. In this
study, the involvement of glutathione in the increased stress resistance earlier
observed in nutrient-starved P. fluorescens was not supported. The concentration
of bacterial glutathione is suggested as a possible marker for rhizosphere
competence, which, however, needs to be further evaluated with several strains of
rhizobacteria.
PMID- 9767709
TI - Nickel uptake by Pseudomonas aeruginosa: role of modifying factors.
AB - Pseudomonas aeruginosa cells growing in minimal medium were 40-fold more
sensitive to Ni2+ than cells growing in enriched medium, suggesting a possible
protective role of medium ingredients. Likewise, cells pre-grown in enriched
medium showed a high Km (6.15 mM) and increased Ni2+ uptake (950 nmol mg-1
protein, 1h) over cells pre-sown in minimal medium (Km, 0.48 mM; 146 nmol mg-1
protein, 1 h). The overall pattern indicates that cells pre-grown in enriched
medium were characterized by having lowered affinity towards Ni2+ than those with
minimal medium background. The enhanced Ni2+ uptake by enriched medium-grown
cells can be correlated with the improved metabolic state of the cells. Ni2+
uptake was optimum at neutrality (pH 7.0). A major Ni2+ transport system was
competitively inhibited by Mg2+, Zn2+, Cd2+, or Co2+ (400 microM each).
Noticeably, a minor Ni2+ transport pathway was still operative even in the higher
concentration range of Mg2+ (4 mM and 40 mM). The stimulation of Ni2+ uptake
monitored in the presence of different carbon sources (0.5% wt/vol, each) showed
the sequence: glucose (1.6-fold) > phenol = gallic acid (1.5-fold). Succinate, in
comparison, reduced Ni2+ uptake (0.5-fold) possibly because of its acting as a
metal chelator as well. Sensitivity of Ni2+ transport towards methyl viologen,
azide, 2-4 DNP, and DCCD suggested that transport was energy-linked.
PMID- 9767711
TI - Lateral and perpendicular interaction forces involved in mobile and immobile
adhesion of microorganisms on model solid surfaces.
AB - Gliding and near-surface swimming of microorganisms are described as a mobile
form of microbial adhesion that need not necessarily be reversible. It is argued
that the reversibility of microbial adhesion depends on the depth of the
secondary interaction minimum, calculated from the forces between an organism and
a substratum acting in a direction perpendicular to the substratum surface. The
mobility of adhering microorganisms depends on lateral interactions between the
organisms. On ideally homogeneous and smooth model surfaces, only mobile adhesion
occurs because the multibody, lateral interactions are weak compared with the
thermal or Brownian motion energy of the organisms. Minor chemical or structural
heterogeneities, which exist on all real-life surfaces, yield a lateral
interaction on adhering microorganisms. This causes their immobilization, which
helps to explain the physicochemical nature of microbial gliding or near-surface
swimming. Moreover, these lateral interaction energies are one order of magnitude
smaller than the Lifshitz-Van der Waals, electrostatic, and acid-base forces
acting perpendicular to substratum surfaces that are responsible for adhesion.
PMID- 9767710
TI - Characterization of the genes encoding the botulinum neurotoxin complex in a
strain of Clostridium botulinum producing type B and F neurotoxins.
AB - The organization of the clusters of genes encoding proteins of the botulinum
neurotoxin (BoNT) progenitor complex was elucidated in a strain of Clostridium
botulinum producing type B and F neurotoxins. With PCR and sequencing strategies,
the type B BoNT-gene cluster was found to be composed of genes encoding BoNT/B,
nontoxic nonhemagglutinin component (NTNH), P-21, and the hemagglutinins HA-33,
HA-17, and HA-70, whereas the type F BoNT-gene cluster has genes encoding BoNT/F,
NTNH, P-47, and P-21. Comparative sequence analysis showed that BoNT/F in type BF
strain 3281 shares highest homology with BoNT/F of non-proteolytic (group II) C.
botulinum whereas NTNH and P-21 in the type F cluster of strain 3281 are more
similar to the corresponding proteins in proteolytic (group I) type F C.
botulinum. These findings indicate diverse evolutionary origins for genes
encoding BoNT/F and its associated non-toxic proteins, although the genes are
contiguous. By contrast, sequence comparisons indicate that genes encoding BoNT/B
and associated non-toxic proteins in strain 3281 possess a similar evolutionary
origin. It was demonstrated that the genes present in the BoNT/B gene cluster of
this type BF strain show exceptionally high homology with the equivalent genes in
the silent BoNT/B gene cluster of C. botulinum type A(B), possibly indicating
their common ancestry.
PMID- 9767712
TI - Protection of mice against challenge with homologous and heterologous serovars of
Actinobacillus pleuropneumoniae after live vaccination.
AB - Protective immune responses and the virulence of Actinobacillus pleuropneumoniae
(APP) have been attributed, in part, to toxins (Apx) produced by the bacterium. A
mutant of the serovar 7 strain HS93 (HS93Tox-), lacking the genes encoding the
structural toxin ApxA and the post-translational activating protein ApxC, but
retaining the genes required for secretion ApxB and ApxD, was isolated and shown
to be attenuated in a mouse model. A plasmid vector system was developed and used
to express the ApxA gene from within the HS93Tox- strain. The resulting strain,
HS93Tox-/pIG-T1K, expresses the Apx structural protein in a non-activated form.
HS93Tox-/pIG-T1K was shown to be attenuated in a mouse model and to be capable of
inducing Apx-specific antibodies, which were boosted on re-inoculation. Live
vaccination of mice with HS93Tox-/pIG-T1K offered protection against homologous
wild-type serovar 7 challenge, and also heterologous challenge with a serovar 1
strain. This is in contrast to vaccination with the HS93Tox- strain, which failed
to protect mice against a heterologous challenge.
PMID- 9767714
TI - Effect of carbon source on production of alpha-L-arabinofuranosidase by
aureobasidium pullulans
AB - A color-variant strain of Aureobasidium pullulans (NRRL Y-12974) produced alpha-L
arabinofuranosidase (alpha-L-AFase) when grown in liquid culture on sugar beet
arabinan, wheat arabinoxylan, L-arabinose, L-arabitol, xylose, xylitol, oat spelt
xylan, corn fiber, or arabinogalactan. L-Arabinose was most effective for
production of both whole-broth and extracellular alpha-L-AFase activity, followed
by L-arabitol. Oat spelt xylan, sugar beet arabinan, xylose, xylitol, and wheat
arabinoxylan were intermediate in their ability to support alpha-L-AFase
production. Lower amounts of enzyme activity were detected in corn fiber- and
arabinogalactan-grown cultures.
PMID- 9767713
TI - Conservation of the major cold shock protein in lactic acid bacteria.
AB - Primers designed from consensus regions of the major cold shock gene of different
bacterial species were used in PCR amplification of Lactic Acid Bacteria (LAB).
An appropriately-sized PCR product was obtained from Lactococcus lactis subsp.
lactis LL43-1 and MG1363; Lactococcus lactis subsp. cremoris LC10-1, LC11-1, and
LC12-1; Streptococcus thermophilus ST1-1; Enterococcus faecalis EF1-1;
Lactobacillus acidophilus LA1-1; Lactobacillus helveticus LH1-1; Pediococcus
pentosaceus PP1-1; and Bifidobacterium animalis BA1-1. The PCR products were
cloned and sequenced. The deduced amino acid sequences displayed high sequence
similarity with the major cold shock proteins of Escherichia coli and Bacillus
subtilis and the human Y-box factor. The amino acid residues of the cold shock
domain implicated in nucleic acid binding in several unrelated species were also
highly conserved in the LAB strains. It is possible, therefore, that this protein
in LAB may also act as a transcriptional enhancer to other cold shock genes
and/or act as an RNA chaperone unwinding tightly folded RNA molecules.
PMID- 9767715
TI - A genomically modified marker strain of Escherichia coli.
AB - Contamination of the environment with human sewage represents a serious public
health concern in which Escherichia coli plays a central role, either directly as
a human pathogen or indirectly through its use as an indicator organism. There is
thus an ongoing effort to better understand the behavior of E. coli within such
environments. Useful to such studies is the ability to readily detect a specific
E. coli population and distinguish it from similar indigenous bacteria. Herein,
we report the construction of an E. coli strain (PCPHR) that expresses a Stable
Artificial RNA (SAR) from the chromosomal rrnH operon. The SAR product is present
in large numbers of copies/cell and thus provides an enhanced detection signal
without significant effect on the wild-type growth rate. Detection can be
accomplished by any of several routine molecular methods. Preliminary studies
suggest SAR expression levels correlate positively with growth. PCPHR is
immediately available for use as a marker strain for E. coli in application in
the arena of public health or environmental studies.
PMID- 9767717
TI - Plasmid-mediated gene transfer between insect-resident bacteria, Enterobacter
cloacae, and plant-epiphytic bacteria, Erwinia herbicola, in guts of silkworm
larvae.
AB - Five strains of Enterobacter cloacae isolated from several species of plants and
insects were able to grow in the guts of silkworm larvae. A much larger
population of Ent. cloacae strains was detected in the insect guts and feces
collected 3 and 6 days than in samples collected 1 day after feeding artificial
diets contaminating these bacteria. Furthermore, insect-origin strains of Ent.
cloacae were mated with a donor strain, epiphytic Erwinia herbicola, harboring
RSF1010 and pBPW1::Tn7 plasmids in the insect guts by introducing these bacteria
through separate artificial diets administered at different times. A number of
transconjugants, Ent. cloacae strains which had acquired RSF1010 plasmid, were
detected from guts and fecal samples at transfer frequencies of 10(-2) to 10(-3)
per recipient. Thus, gene transfer between epiphytic Er. herbicola and insect
resident Ent. cloacae strains in the insect guts was confirmed. These findings
may provide significant information about the role of "in insecta mating" in the
evolution of these bacteria.
PMID- 9767716
TI - Transfer and expression of a multiple antibiotic resistance plasmid in marine
bacteria.
AB - Conjugal transfer of a multiresistance plasmid from Pseudomonas fluorescens to
halophilic and halotolerant bacteria was studied under in vitro and in situ
conditions. Mating conducted in broth as well as on plates yielded a plasmid
transfer frequency of as high as 10(-3). Among these two, plate mating
facilitated conjugal transfer of plasmid, because the cell-to-cell contact is
more in plate mating. When P. fluorescens was incubated in seawater, the organism
progressively lost its colony forming activity within 15 days. Microscopic
examination revealed the presence of very short rods, indicating that the cells
have become viable but nonculturable (VNC). Mating conducted in natural seawater
without any added nutrients revealed that the conjugal transfer is influenced by
the physical state of the donor and the recipients as well as the availability of
nutrients. But a plasmid transfer frequency of 10(-7) was obtained even after the
donor cells have become VNC suggesting that the nonculturable state and nutrient
deprived condition may not limit plasmid transfer. The results suggest that the
terrestrial bacteria entering into the seawaters with antibiotic resistance
plasmids may be responsible for the prevalence of resistance genes in the marine
environment.
PMID- 9767718
TI - Buchnera aphidicola (Aphid endosymbiont) contains genes encoding enzymes of
histidine biosynthesis.
AB - Buchnera aphidicola is an endosymbiont of aphids. One of its functions appears to
be the synthesis of essential amino acids for the aphid host. A 12.8-kilobase B.
aphidicola DNA fragment has been cloned and sequenced. It contains genes encoding
all of the enzymes required for the biosynthesis of the essential amino acid
histidine. The order of the genes, hisGDCBHAFI, is the same as that found in
Escherichia coli and is consistent with their constituting a single transcription
unit. The DNA fragment also contained genes involved in aromatic amino acid
biosynthesis (aroC), the oxidative pentose pathway (gnd), and 2'
deoxyribonucleotide metabolism (dcd), as well as a tRNA synthase (metG).
PMID- 9767719
TI - Isolation of adenylate cyclase gene-specific sequences from Ophiostoma novo-ulmi,
Candida albicans, and Agaricus bisporus by PCR.
AB - Degenerate primers corresponding to consensus sequences in the catalytic domains
of known fungal adenylate cyclases were used to isolate gene-specific homologs
from the Dutch elm disease pathogen Ophiostoma novo-ulmi, the dimorphic human
pathogen Candida albicans, and the commercial mushroom Agaricus bisporus. All
three fungi gave the expected PCR product of about 390 bp. Computer searches of
the databases revealed that the products generated from O. novo-ulmi and C.
albicans were highly similar to the adenylate cyclase gene of Magnaporthe grisea,
the rice blast fungus (91% and 79%, respectively). The PCR product from the
homobasidiomycete A. bisporus, on the other hand, showed 78% similarity to the
uac1 gene of the heterobasidiomycete smut fungus, Ustilago maydis. Southern
hybridization indicated that all three fungi contain a single adenylate cyclase
gene. Our data suggest that PCR will be highly successful for the isolation of
adenylate cyclase sequences from other fungi.
PMID- 9767721
TI - Impact of family physicians on mammography screening.
PMID- 9767720
TI - Vaccinations in adults: missed opportunities.
PMID- 9767722
TI - Measles, mumps, rubella vaccine and allergy to egg.
PMID- 9767723
TI - Tibiofibular diastasis in the injured ankle.
PMID- 9767724
TI - Recognizing neoplastic skin lesions: a photo guide.
AB - Malignant lesions of the skin are common. Patients who develop squamous cell
carcinoma and malignant melanoma often have recognizable precursor conditions. A
few skin lesions resemble malignancies. Lesions that are growing, spreading or
pigmented, or those that occur on exposed areas of skin are of particular
concern. Knowing the similarities and differences between these lesions allows
the primary physician to make a diagnosis in most cases by simple inspection and
palpation. When in doubt, it is appropriate to perform an excisional biopsy of
small lesions or punch biopsy of larger lesions. Removal of premalignant lesions
will reduce the occurrence of malignant disease. Almost all skin cancers can be
cured by early excision or destruction. For these reasons, physicians should be
aware of the risk factors for skin cancer, educate patients about risk reduction
and include skin inspection for premalignant and malignant lesions as a part of
routine health maintenance examinations.
PMID- 9767725
TI - The Gomco circumcision: common problems and solutions.
AB - Circumcision performed using the Gomco clamp is usually quick and effective, and
results in very little bleeding. However, every clinician performing circumcision
occasionally has concerns or questions regarding the procedure. Some of the more
common concerns regarding the use of the Gomco clamp are technique-related,
including choosing the correct size of the Gomco bell and clamp for the
procedure, choosing the right method of getting the foreskin properly through the
hole of the Gomco base plate, and assessing how much foreskin to remove. Other
concerns include poor cosmetic results, contraindications to routine
circumcision, and circumcision in an infant whose mother has human
immunodeficiency virus. This article reviews the technique of circumcision using
the Gomco clamp and answers some of the more common questions.
PMID- 9767727
TI - Management of female sexual assault.
AB - A sexual assault occurs once every 6.4 minutes in the United States. One in every
six women will be raped during her lifetime. Although a woman is four times more
likely to be assaulted by someone she knows than by someone she does not know,
the majority of these crimes go unreported even though rape is a felony. The
purpose of the medical examination after a sexual assault is to assess the
patient for physical injuries and to collect evidence for forensic evaluation and
possible legal proceedings. Laboratory samples should be obtained at the initial
visit and should include testing for pregnancy, syphilis, hepatitis B and human
immunodeficiency virus infection. Treatment should address physical injuries,
pregnancy prophylaxis, sexually transmitted diseases and psychosocial sequelae.
Appropriate referral services should be initiated during the initial visit.
Victims of sexual assault require appropriate care, follow-up and information
regarding their legal rights. Family physicians should be familiar with the state
laws governing collection of evidence and should be prepared to advise the
patient to report the crime. The history should be confined to medically relevant
facts and should be conducted in a safe and quiet environment.
PMID- 9767726
TI - Constipation in the elderly.
AB - Constipation affects as many as 26 percent of elderly men and 34 percent of
elderly women and is a problem that has been related to diminished perception of
quality of life. Constipation may be the sign of a serious problem such as a mass
lesion, the manifestation of a systemic disorder such as hypothyroidism or a side
effect of medications such as narcotic analgesics. The patient with constipation
should be questioned about fluid and food intake, medications, supplements and
homeopathic remedies. The physical examination may reveal local masses or
thrombosed hemorrhoids, which may be contributing to the constipation. Visual
inspection of the colon is useful when no obvious cause of constipation can be
determined. Treatment should address the underlying abnormality. The chronic use
of certain treatments, such as laxatives, should be avoided. First-line therapy
should include bowel retraining, increased dietary fiber and fluid intake, and
exercise when possible. Laxatives, stool softeners and nonabsorbable solutions
may be needed in some patients with chronic constipation.
PMID- 9767728
TI - Recognizing occupational disease--taking an effective occupational history.
AB - Occupational exposures contribute to the morbidity and mortality of many
diseases. However, occupational diseases continue to be underrecognized even
though they are responsible for an estimated 860,000 illnesses and 60,300 deaths
each year. Family physicians can play an important role in improving the
recognition of occupational disease, preventing progressive illness and
disability in their own patients, and contributing to the protection of other
workers similarly exposed. This role can be maximized if physicians raise their
level of suspicion for workplace disease, develop skills in taking occupational
histories and establish routine access to occupational health resources.
PMID- 9767730
TI - Keeping abreast of new drug approvals and labeling changes.
PMID- 9767729
TI - Short-term tuberculosis prophylaxis is effective in persons with HIV.
PMID- 9767731
TI - AAP issues policy statement on parental discipline of children.
PMID- 9767732
TI - ACOG releases report on risk factors, causes and management of postpartum
hemorrhage.
PMID- 9767733
TI - The value of dose intensification of standard chemotherapy for advanced breast
cancer using colony-stimulating factors alone.
PMID- 9767734
TI - Sentinel node biopsy: a revolution in the surgical management of breast cancer?
PMID- 9767737
TI - The status of transfusion medicine science and the role of the American
Association of Blood Banks: the journey continues.
PMID- 9767735
TI - The development of combination therapy involving camptothecins: a review of
preclinical and early clinical studies.
PMID- 9767736
TI - Hormonal therapy of breast cancer.
PMID- 9767738
TI - Interagency Genome Amplification Testing Task Force: preliminary report.
PMID- 9767739
TI - Mini-pool screening by nucleic acid testing for hepatitis B virus, hepatitis C
virus, and HIV: preliminary results.
AB - BACKGROUND: The purpose of this study was to evaluate the feasibility of nucleic
acid testing (NAT) of mini-pools as a blood donation screening test. STUDY DESIGN
AND METHODS: The stepwise implementation of NAT of mini-pools began in January
1997. Since March 1997, all blood donations collected by the German Red Cross
Blood Transfusion Service of Baden-Wurttemberg were tested for hepatitis B virus
(HBV), hepatitis C virus (HCV), and HIV nucleic acids. An extra barcoded serum
sample is collected from each blood donor for NAT-based screening, which is
performed only on hepatitis B surface antigen-, anti-HCV-, anti-HIV-, and anti
Treponema pallidum-seronegative donations. Samples are pooled to a maximum of 96.
Positive results are resolved through intersecting subpools (a chessboard
design). NAT-based screening does not include a virus concentration step before
nucleic acid extraction. RESULTS: By the end of October 1997, 331, 783 donations
in 3,779 pools had been screened. As yet, no viremic but seronegative blood donor
has been found for the three markers. CONCLUSION: It is feasible to incorporate
NAT-based screening of mini-pools into the routine virus diagnostics of a large
blood transfusion service. It remains to be determined whether screening blood
donations by NAT will indeed increase the safety of blood supply.
PMID- 9767740
TI - The use of polymerase chain reaction in plasma pools for the concomitant
detection of hepatitis C virus and HIV type 1 RNA.
AB - BACKGROUND: Detection of viral nucleic acids might increase blood transfusion
safety through the detection of recently infected blood donors during the
preseroconversion window period. Individual screening is difficult to apply,
because of technical and financial constraints. STUDY DESIGN AND METHODS: A
polymerase chain reaction (PCR)-based assay including a polyethylene glycol
precipitation step was developed for the concomitant detection of hepatitis C
virus (HCV) and HIV type 1 (HIV-1) RNA in plasma pools corresponding to 50 blood
donations by the use of commercial assays. RESULTS: The assay had a sensitivity
of less than 33 copies per mL for HCV RNA and 1000 copies per mL for HIV-1 RNA
for each individual sample included in the pool. The eight preseroconversion
samples with HCV RNA between 1,250 and 762,000 copies per mL were all detected
when 100-microL aliquots from the samples were introduced into 5-mL pools of 50
blood donations. CONCLUSIONS: A PCR-based pooling assay associating a
prepurification step with polyethylene glycol allows for the screening of blood
donations for HCV and HIV-1 RNA without marked loss of sensitivity from that seen
with commercially available assays. This procedure might increase blood safety
through systematic screening of blood donations at relatively low cost.
PMID- 9767741
TI - Screening blood donations for viral genomes: multicenter study of real-time
simulation using pooled samples on the model of hepatitis C virus RNA detection.
AB - BACKGROUND: The systematic screening for several blood-borne viral genomes in
blood donations is a complementary safety measure planned or discussed by the
national authorities of several countries. STUDY DESIGN AND METHODS: To
appreciate the feasibility of such screening using pooled samples, a multicenter
study of real-time simulation has been performed on the model of hepatitis C
virus (HCV) infection. Four blood transfusion center laboratories and two
research and diagnosis laboratories simultaneously screened, by several HCV RNA
polymerase chain reaction assays, a panel of plasma sample pools of different
sizes (500, 100, and 10 samples), collected from HCV-infected or HCV-uninfected
blood donors. One viremic plasma was introduced in each pool. HCV RNA was
detected by in-house polymerase chain reaction procedures or by standardized
manual or semi-automated polymerase chain reaction assays. RESULTS: The results
indicate the feasibility of sample pooling, which renders the screening for viral
genomes by molecular biology techniques applicable in the short term and the
importance of the experience of laboratory personnel in the use of molecular
biology tools. CONCLUSION: The improvement of standardized assays needs to be
continued, and training of laboratory staff members appears to be a crucial step
before systematic screening of blood donations for viral genomes by molecular
biology techniques can occur.
PMID- 9767742
TI - Perioperative myocardial ischemic episodes are related to hematocrit level in
patients undergoing radical prostatectomy.
AB - BACKGROUND: The anemia associated with perioperative blood conservation has
raised concerns regarding the safety of these strategies in patients with
ischemic cardiovascular disease. Therefore the relationship between hematocrit
level and myocardial ischemic episodes in a group of elderly patients undergoing
elective noncardiac surgery was studied. STUDY DESIGN AND METHODS: One hundred
ninety patients undergoing radical prostatectomy were randomly assigned to one of
three blood conservation groups: preoperative autologous blood donation, acute
normovolemic hemodilution, and preoperative erythropoietin therapy with acute
normovolemic hemodilution. Patients underwent ambulatory electrocardiography
monitoring to evaluate for myocardial ischemia at randomization (baseline), 7
days preoperatively, throughout surgery, and for 24 hours after surgery. RESULTS:
Myocardial ischemic episodes occurred in 61 (34%) of 181 evaluable patients.
Patients with hematocrit levels < 28 percent immediately after surgery were
significantly (p = 0.05) more likely to have intraoperative and postoperative ECG
ischemic episodes. Intraoperative ischemia and tachycardia correlated (r = 0.21,
p = 0.008) with hematocrit levels. Hematocrit levels after surgery were
associated with postoperative ischemia (r = 0.14, p = 0.03) and duration of
myocardial ischemic episodes (r = 0.14, p = 0.04). After adjusting for other risk
factors, intraoperative tachycardia episodes, hematocrit level < 28 percent
immediately after surgery, and risk factors for coronary artery disease were
independently associated with the likelihood of intraoperative ischemia (r =
0.36, p = 0.002, area under receiver operating characteristic curve = 0.73).
Similarly, tachycardia episodes and hematocrit levels < 28 percent immediately
after surgery were independently associated with ischemic episodes during the
first postoperative day (r = 0.30, p = 0.004, area under receiver operating
characteristic curve = 0.71). CONCLUSION: A hematocrit level < 28 percent is
independently associated with risk for myocardial ischemia during and after
noncardiac surgery. Avoidance of cardiac complications may require higher
transfusion thresholds, closer attention to tachycardia, or better monitoring for
ischemia.
PMID- 9767743
TI - Prospective validation of a point score system for predicting blood transfusion
following hip or knee replacement.
AB - BACKGROUND: The purpose of this study was to validate a previously published
point score system for predicting the likelihood of a postoperative blood
transfusion following hip or knee replacement. STUDY DESIGN AND METHODS: Data
were collected prospectively on 460 sequential patients undergoing elective hip
and knee replacement at two academic hospitals. Blood transfusion frequency was
determined for patients in each of the four risk strata, as defined by the point
score system. The accuracy of the system was validated by calculating the area
under the receiver operating characteristic (ROC) curve for each site. Data were
then combined and inappropriate blood transfusions were eliminated, by using the
American College of Physicians guidelines. The frequencies of blood transfusion
within each strata were recalculated along with an ROC curve. RESULTS: The point
score system accurately predicted the likelihood of blood transfusion at both
hospitals, despite marked differences in overall transfusion frequencies. The
calculated areas under the ROC curves were 0.78 and 0.79 for the two sites. The
point score system also proved valid when only appropriate blood transfusions
were considered, with a calculated area under the ROC curve of 0.74. CONCLUSION:
The point score system can accurately predict the likelihood of postoperative
blood transfusion following hip or knee replacement. Such a system can be used to
target high-risk patients for preoperative autologous blood donation.
PMID- 9767744
TI - Frequency of immediate adverse effects associated with apheresis donation.
AB - BACKGROUND: Apheresis donation is considered safe, but the incidence of adverse
effects has not been determined in a large multicenter series of donations with
modern instruments. STUDY DESIGN AND METHODS: The Hemapheresis Committee of the
American Association of Blood Banks devised a uniform questionnaire that asked
about 32 specific adverse effects. Transient paresthesia and mild vasovagal
events were excluded. A survey was conducted in 1995; 17 centers returned 19,611
responses concerning 250 to 2,000 consecutive apheresis donations per center.
RESULTS: Six hundred adverse effects were reported in 428 donations (2.18% of
donations). Pain or hematoma at a venipuncture site was the most common response
(1.15% of donations); only 203 donations had other (nonvenipuncture) adverse
effects (1.04%). Total and nonvenipuncture rates were, respectively, 4.84 and
2.92 percent for 2,295 first donations and 1.78 and 0.77 percent for 17,303
repeat donations (p < 0.001). Rates of nonvenipuncture symptoms in first and
repeat donations were, respectively, citrate-induced nausea and/or vomiting, 0.87
and 0.27 percent; tetany, 0.09 and 0.04 percent; pallor and/or diaphoresis, 1.87
and 0.32 percent; vasovagal nausea and/or vomiting, 0.87 and 0.13 percent;
syncope and/or seizure, 0.39 and 0.04 percent; and chills and/or rigors, 0.31 and
0.01 percent. The overall rate of donor unconsciousness was 0.08 percent.
Hemolysis was reported twice. Clotting or leakage occurred in 0.08 percent of
donations, and inability to return blood occurred in 0.16 percent. No life
threatening adverse effects were reported. Procedure-specific nonvenipuncture
rates were 1.05 percent of 17,584 platelet donations, 0.67 percent of 594 white
cell donations, and 0.37 percent of 1,354 plasma donations. Center-specific rates
varied from 0.32 to 6.81 percent of donations for total adverse effects and from
0.11 to 2.92 percent of donations for nonvenipuncture events. CONCLUSION:
Apheresis donation is a safe undertaking, suitable for voluntary blood donors,
with a very low risk of serious adverse effects. The risk of unconsciousness is
lower than that found in many studies of whole-blood donation.
PMID- 9767745
TI - Intra-apheresis recruitment of blood progenitor cells in children.
AB - BACKGROUND: Determination of the optimal duration of apheresis requires a careful
examination of blood progenitor cell (BPC) kinetics during apheresis. Intra
apheresis recruitment of BPCs should be evaluated. STUDY DESIGN AND METHODS:
Twenty-six apheresis procedures were performed in 13 children with various
malignant disorders (ages, 10 months to 17 years; median, 7 years) to collect
BPCs for autologous transplant, using a blood cell separator with 2 to 5.2 blood
volumes processed. The subjects were divided into three groups according to age:
below 1 year (n = 4), 2 to 10 years (n = 5), and 11 to 20 years (n = 4). BPCs
were mobilized by a combination of chemotherapy and granulocyte-colony
stimulating factor (G-CSF; 2-7.5 micrograms/kg/day intravenous drip). The levels
of circulating CD34+ cells and colony-forming units-granulocyte-macrophage (CFU
GM) were monitored to examine intra-apheresis recruitment. For every 50 mL per kg
or 2 L of processed blood, 5-mL blood samples were collected via a central line.
RESULTS: In the first apheresis procedure, more CD34+ cells were mobilized by the
procedure itself in the infant group than in the older groups, and the number of
cells decreased with the subject's age. When the same analysis was made during
the second apheresis procedure, performed 1 day later, the levels of both CD34+
cells and CFU-GM had decreased to below the preapheresis values in all of the
populations. Cell yields in the second apheresis procedure were significantly
lower than those in the first. CONCLUSION: Although several factors prevent a
reliable analysis, the data suggest that the intra-apheresis recruitment of BPCs
may be age-specific; the continuous and prolonged supply of cells from the bone
marrow to peripheral blood that occurs during apheresis is more predominant in
infants, which leads to the collection of proportionately more BPCs in younger
children than in their older counterparts.
PMID- 9767747
TI - Evaluation of a new automated instrument for pretransfusion testing.
AB - BACKGROUND: A number of automated devices for pretransfusion testing have
recently become available. This study evaluated a fully automated device based on
column agglutination technology (AutoVue System, Ortho, Raritan, NJ). STUDY
DESIGN AND METHODS: Some 6747 tests including forward and reverse ABO group, Rh
type and phenotype, antibody screen, autocontrol, and crossmatch were performed
on random samples from 1069 blood donors, 2063 patients, and 98 newborns and cord
blood. Also tested were samples from 168 immunized patients and 53 donors
expressing weak or variant A and D antigens. Test results and technician times
required for their performance were compared with those obtained by standard
methods (manual column agglutination technology, slide, semiautomatic handler).
RESULTS: No erroneous conclusions were found in regard to the 5028 ABO group and
Rh type or phenotype determinations carried out with the device. The device
rejected 1.53 percent of tests for sample inadequacy. Of the remaining 18 tests
with discrepant results found with the device and not confirmed with the standard
methods, 6 gave such results because of mixed-field reactions, 10 gave negative
results with A2 RBCs in reverse ABO grouping, and 2 gave very weak positive
reactions in antibody screening and crossmatching. In the samples from immunized
patients, the device missed one weak anti-K, whereas standard methods missed five
weak antibodies. In addition, 48, 34, and 31 of the 53 weak or variant antigens
were detected by the device, the slide method, and the semiautomated handler,
respectively. Technician time with the standard methods was 1.6 to 7 times higher
than that with the device. CONCLUSION: The technical performance of the device
compared favorably with that of standard methods, with a number of advantages,
including in particular the saving of technician time. Sample inadequacy was the
most common cause of discrepancy, which suggests that standardization of sample
collection can further improve the performance of the device.
PMID- 9767746
TI - The VS and V blood group polymorphisms in Africans: a serologic and molecular
analysis.
AB - BACKGROUND: VS and V are common red cell antigens in persons of African origin.
The molecular background of these Rh system antigens is poorly understood. STUDY
DESIGN AND METHODS: Red cells from 100 black South Africans and 43 black persons
from Amsterdam, the Netherlands, were typed serologically for various Rh system
antigens. Allele-specific polymerase chain reaction and sequencing of polymerase
chain reaction products were used to analyze C733G (Leu245Val) and G1006T
(Gly336Cys) polymorphisms in exons 5 and 7 of RHCE and the presence of a D-CE
hybrid exon 3. RESULTS: The respective frequencies of all VS+ and of VS+ V-(r's)
phenotypes were 43 percent and 9 percent in the South Africans and 49 percent and
12 percent in the Dutch donors. All VS+ donors had G733 (Val245), but six with
G733 were VS- (4 V+w, 2 V-). The four VS- V+w donors with G733 appeared to have a
CE-D hybrid exon 5. T1006 (Cys336) was present in 12 percent and 16 percent of
donors from the two populations. With only a few exceptions, T1006, a D-CE hybrid
exon 3, and a C410T (Ala137Val) substitution were associated with a VS+ V
phenotype ((C)ces or r's haplotype). Two VS+ V-individuals, with the probable
genotype, (C)ces/(C)ces), were homozygous for G733 and for T1006. CONCLUSIONS: It
is likely that anti-VS and anti-V recognize the conformational changes created by
Val245, but that anti-V is sensitive to additional conformational changes created
by Cys336.
PMID- 9767748
TI - Clinical trial and local process evaluation of an apheresis system for
preparation of white cell-reduced platelet components.
AB - BACKGROUND: A new method for the consistent preparation of white cell (WBC)
reduced plateletpheresis components, the Spectra Leukoreduction System (LRS), was
evaluated by clinical trial and local process validation. The centrifuge-based
system was projected to decrease the WBC content of plateletpheresis components
to a level below 1 x 10(6) per unit. Phase I and II clinical trials were
performed. The manufacturer's claims were then tested at the local level with an
ongoing quality assurance program. STUDY DESIGN AND METHODS: In Phase I, a cross
over analysis of five subjects compared LRS to standard plateletpheresis
procedures in collection efficiency and component quality: a panel of in vitro
measures was taken on Day 0 and Day 5. In Phase II, the LRS process was tested on
a larger scale (n = 57; control = 58) with component transfusion. Finally,
validation, determination of degree of conformance with standards, and ongoing
quality control were performed locally on a newly installed instrument. RESULTS:
Phase I and II trials revealed no significant differences between LRS and control
units in donor or recipient safety and comfort, platelet function and yield, or
component volume. WBC per-unit values were significantly different: the LRS
median per unit was 3.2 x 10(4) WBCs, versus 81.4 x 10(4) for control units.
Assessment of process capability gave an estimate of 99-percent confidence that
99.5 percent of LRS units would be WBC reduced to < 1 x 10(6) WBCs. Local process
validation and quality control revealed 90-percent confidence that 99 percent of
the units would be WBC reduced and 99.9-percent confidence that 75 percent would
exceed platelet yield standards; the process was stable over time. CONCLUSIONS:
The LRS is safe for apheresis and the component produced is safe for transfusion
with platelet function and yield equivalent to controls and WBC reduction
superior to controls. Local process evaluation confirmed that component quality
meets the goals of the institution.
PMID- 9767749
TI - The histo-blood group ABO system and tissue transplantation.
AB - In general, one might expect that ABO incompatibility of donor and recipient
would be important to some degree if viability of the transplanted allograft is
important for graft incorporation and function. This is true for some recipients
of organs. However, ABO incompatibility appears to play a minor role, if any, in
the clinical success of viable cornea and viable skin allografts. Even though A
and B antigens may be present on the transplanted tissue, other factors that can
contribute include the strength of the immune response, the avidity of the
antibody, and the dose of the antigen presented, which may vary from donor to
donor. Although A and B antigens are present on endothelium, the use of ABO
incompatible heart valves is successful, as they carry out their mechanical
function by using the strength of the connective tissue rather than the viability
of the donor endothelium. The presence, immunogenicity, and significance of A and
B antigens in human vessel transplants have not been well studied. With the more
commonly transplanted tissue, such as bone and tendon, posttransplant success
does not depend on cellular viability or ABO compatibility.
PMID- 9767750
TI - Contribution of nucleic acid amplification techniques to the safety of blood
components in France.
PMID- 9767751
TI - Lipid priming agents and transfusion-related acute lung injury.
PMID- 9767753
TI - [Quality of life of women with stress urinary incontinence with or without
pollakiuria].
AB - OBJECTIVES: Assess improvement in quality of life using a validated scale in
women with urge incontinence or pollakiuria treated with oxybutynine. PATIENTS
AND METHODS: A prospective open multicentric trial was conducted in 1701 women
aged 20 to 60 years (mean 47.6) with the last 2 months. Quality of life was
assessed on the Ditrovie scale before and after a 3-month treatment with
oxybutynin (7.5 to 15 mg/day). RESULTS: Patient compliance was good (97%) and
side effects rare (8%) (mainly dry mouth). There was a significant symptom
improvement (p < or = 0.0001) between day 0 and day 90 after treatment: 48% of
the women no longer had incontinence with a safety interval of more than 15
minutes compared with 0.2% prior to treatment; urge incontinence disappeared in
75% of the 81% affected women; 82% of the women had an intermictional interval
longer than 2 hours after treatment compared with 33% prior to treatment. There
was a significant improvement in the quality of life scores after treatment (p <
0.0001), as assessed by the overall score and subscores (daily life, emotional
impact, self-image, sleep, well-being). CONCLUSION: These findings demonstrate
the efficacy of oxybutynine in improving urge incontinence and pollakiuria in
women, both in terms of symptom relief and quality of life.
PMID- 9767755
TI - [POEMS syndrome with primary adrenocortical insufficiency].
AB - BACKGROUND: POEMS syndrome is a multisystem disorder. It usually presents as
severe polyneuropathy and monoclonal gammapathy associated with endocrinopathies,
organomegaly, skin hyperpigmentation. CASE REPORT: A patient with POEMS syndrome
developed primary adrenocortical deficiency revelated by asthenia and
hyperpigmentation. Hydrocortisone replacement therapy produced a rapidly
beneficial effect on asthenia and hyperpigmentation. DISCUSSION: Although
asthenia and skin pigmentation are common in POEMS syndrome, adrenocortical
deficiency is seldom reported. This endocrinopathy might be underestimated in
POEMS patients. We suggest systematic screening with a rapid ACTH test in all
POEMS patients in order to detect underlying adrenal deficiency.
PMID- 9767754
TI - [Diagnostic criteria for progressive necrotizing external otitis. Are
scintigraphic findings reliable?].
AB - OBJECTIVES: Determine the role of 99m technetium scintigraphy for diagnosis in
progressive necrotizing external otitis and assess the diagnostic criteria of
this disease. METHOD: A retrospective study was conducted in 16 patients
hospitalized for suspected progressive necrotizing external otitis. Patient
characteristics, clinical features, imaging findings and disease course were
recorded in order to evaluate the classical criteria of diagnosis. RESULTS: The
clinical course and complementary test results showed that 99m technetium
scintigraphy lacked specificity for progressive necrotizing external otitis.
These findings are in disagreement with those reported in the literature.
CONCLUSION: Patient characteristics and clinical course are key elements for
early diagnosis of this disease. Scintigraphy findings are contributive only when
bone lysis (which occurs late) can be evidenced. A prospective study would be
required to confirm the lack of specificity of scintigraphy in progressive
necrotizing external otitis.
PMID- 9767756
TI - [The role of ultrasonography in the detection of neck injuries].
PMID- 9767757
TI - [Cholecystectomy in respiratory insufficiency: role of laparoscopy with abdominal
lift].
PMID- 9767758
TI - [Intestinal lymphangiectasis associated with ileal tuberculosis].
PMID- 9767759
TI - [Thrombosis, low-molecular-weight heparin-induced thrombocytopenia and labor].
PMID- 9767760
TI - [Chronic inflammatory bowel disease: new insight from genetics].
AB - The cause of chronic inflammatory bowel disease remains unknown. A genetic origin
has been suggested by studies in twins. The gene or genes involved in Crohn's
disease is probably situated on chromosome 16 and the genes involved in
ulcerative colitis on chromosomes 2 and 7. It will undoubtedly take some time
before the exact loci are precisely identified, but current research suggests
that clinical applications are not far off.
PMID- 9767761
TI - [Management of sinusitis in adults].
PMID- 9767762
TI - [NSAID in Alzheimer disease].
PMID- 9767763
TI - [Epidemiology and genetics of chronic inflammatory bowel disease].
PMID- 9767764
TI - [Management of multiresistant pulmonary tuberculosis].
PMID- 9767765
TI - [Prevention of resistance to antibiotics. A complex problem].
PMID- 9767767
TI - [Prevention of infection at the extreme ages of life].
PMID- 9767766
TI - [Antibiotic pressure and bacterial resistance in the hospital].
PMID- 9767768
TI - [Emergence of Gram-positive bacteria in nosocomial transmission].
PMID- 9767769
TI - [Perspectives in antibiotic prophylaxis].
PMID- 9767770
TI - [Pneumococcal resistance to beta-lactams: implications for the treatment of acute
otitis media].
PMID- 9767772
TI - [Questions on hematology].
PMID- 9767771
TI - [Prescription of a hematopoietic growth factor, lenograstim, in current practice.
Results and commentaries of a national survey from April 1995 to March 1996].
AB - OBJECTIVES: The French drug authorities audited first-time prescription of
hematopoietic growth factors using a prescription follow-up survey. Data
collected between April 1995 and March 1996 were analyzed then criticized by
three clinical experts working in three different areas where lenograstime is
most widely used. METHODS: First-time prescription data and follow-up information
were recorded on separate inclusion and follow-up diaries by the prescribing
physicians. The delivering pharmacies complete the diaries and addressed them to
the INSERM unit 330 for analysis. RESULTS: There were 7,102 inclusion diaries and
1376 follow-up diaries from 234 different hospital facilities. Lenograstime was
most frequently prescribed in patients with lymphoma (19%), breast cancer
(16.4%), and lung cancer (13.8%). Prescriptions involved 377 different
chemotherapy protocols, including 196 which concerned a single patient. At the
first prescription, lenograstime was given as a preventive measure in 61% of the
cases and for curative therapy in 25.3%. The planned duration of preventive
treatment was longer than the true period of treatment. DISCUSSION: Pr Rossi,
hematologist, Pr Misset, cancerologist and Pr Lebeau, pneumologist criticized the
findings.
PMID- 9767774
TI - [Questions on pneumology].
PMID- 9767773
TI - [Questions on oncology].
PMID- 9767775
TI - [Extensive bone marrow necrosis and thrombotic microangiopathic anemia revealing
disseminated adenocarcinoma].
AB - BACKGROUND: Bone marrow necrosis and thrombotic microangiopathy are uncommonly
associated. We report an observation. CASE REPORT: A 52-year-old man with
extensive bone marrow necrosis, associated with hemolytic microangiopathic
anemia, was treated unsuccessfully with corticosteroids and plasmapheresis.
Outcome was fatal. Autopsy showed disseminated bone marrow necrosis and medullary
invasion by adenocarcinoma cells in this patient operated 13 years earlier for
gastric cancer. DISCUSSION: Extensive bone marrow necrosis or thrombotic
microangiopathy can complicate usually advanced cancer. Prognosis is poor without
response to chemotherapy. Corticosteroids and plasma exchange are sometimes
successful. A relative efficacy of treatment with staphylococcal protein A
immunopheresis is reported by several authors in thrombotic microangiopathy.
PMID- 9767776
TI - [Hepatic amebiasis: an unusual clinical presentation].
AB - BACKGROUND: Painful liver enlargement with fever are common signs of hepatic
ambiasis. Exceptionally, atypical signs may also occur including symptoms
suggesting renal sepsis. CASE REPORT: An 18-year-old woman from the New Caledonia
was hospitalized in metropolitan France for suspected right-sided acute
pyelonephritis. Urinalysis was normal and the kidney ultrasound suggested the
need for an abdominal CT-scan which evidenced a voluminous 10-cm abscess pus.
Serology for amebia was positive, confirming the diagnosis of hepatic amebic
abscess. Outcome was rapidly favorable with intravenous anti-parasite treatment
amebic abscess. Outcome was rapidly favorable with intravenous anti-parasite
treatment and percutaneous drainage. DISCUSSION: Atypical signs of hepatic
ambiasis may mislead diagnosis. The absence of a fetid odor at puncture helps
guide diagnosis, confirmed by serology. Percutaneous drainage can hbe proposed
for voluminous abscesses or if the risk of extrahepatic complications is eminent.
PMID- 9767777
TI - [Major circulatory and medullary eosinophilia revealing renal cell carcinoma].
PMID- 9767778
TI - [Chylothorax as a complication of Kaposi sarcoma].
PMID- 9767779
TI - [Borrelia pneumonia: an unusual form of borreliosis].
PMID- 9767780
TI - [The hematologist, the nutritionist and the plastician: vitamin K deficiency
during a weight reducing diet].
PMID- 9767781
TI - [Local corticosteroid therapy in the treatment of lumbar sciatica].
PMID- 9767782
TI - [Tumor angiogenesis inhibitors: media and scientific aspects].
AB - Work begun more than 30 years ago at Children's Hospital in Boston led to the
publication of an article on the antiangiogenic properties of two compounds,
endostatin and angiostatin (J. Folkman, Nature 1997; 390:404-7). It only took
weeks for the medias in the US and then in France and the rest of Europe to
stimulate the fervor of patients for this new 'cure' for cancer. Insight into the
fundamental role of angiogenesis in locoregional and metastatic development of
cancer has been accumulated over the last decades. Factors stimulating tumoral
angiogenesis include aFGF, bFGF, VEGF, angiogenin, and other more recently
discovered substances. Likewise, factors inhibiting tumoral angiogenesis,
including angiostatin, have been identified. Angiostatin is a specific inhibitor
of endothelial cell growth that migh appear rapidly in the serum of patients with
a primary tumor. Angiostatin could have both local and systemic effects and
possibly protect against metastatic dissemination in vivo. The importance of
angiogenesis inhibitors was emphasized at the recent meeting of the American
Association for Cancer Research (New Orleans March 28-April 1, 1998). To date, at
least eleven compounds are being tested. Currently, most are in phase 1 or 2; for
the few in phase 3, marketing approval will undoubtedly require several years. It
is interesting to note that neither endostatin nor angiostatin are among the list
of drugs under clinical assessment, first because these small human proteins are
not available in sufficient quantity for therapeutic trials and secondly, because
the processes necessary to produce pure and safe compounds remain to be
developed. Even after these steps have been accomplished, preclinical evaluations
will have to be performed before the first clinical trials could be envisaged.
For the time being, antiangiogenesis remains a promising avenue of anti-cancer
research but neither endostatin nor angiostatin will be available for human
research for several months at least.
PMID- 9767783
TI - [Sildenafil: hopeful or unreasonable?].
AB - Due to its specific action on the intracavernous mechanism of erection,
sildenafil is the first oral treatment for erectile dysfunction therefore much
more effective than earlier oral therapies. Patient acceptance is greatly
improved with the simple oral dose one hour before sexual activity, avoiding
commonly observed dissatisfaction with intracavernal injections or vacuum
devices: will its efficiency be the same? Treatment with nitrate derivatives for
angina pectoris is the major contraindication. Global management, for the patient
and his partner, remains essential for optimal efficacy of this new compound.
Considering patient habits and medical prescriptions in France where use of anti
anxiety and anti-insomnia drugs is relatively high but use of vitamins and
regenerating drugs relatively low, only the future will tell whether use of
sildenafil will remain within 'reasonable' limits. No decision concerning
reimbursement by the French Social Security health care scheme has been made to
date.
PMID- 9767785
TI - [Management of VZV infections. Short text of the 11th consensus conference on
anti-infectious therapies].
PMID- 9767784
TI - [Cancerology: search for better therapeutic schemes].
PMID- 9767786
TI - [Management of varicella-zoster virus infections. No systematic vaccination
against varicella in France].
PMID- 9767787
TI - [From insulin secretion to insulin therapy].
PMID- 9767788
TI - [Insulin injections: techniques and plans].
PMID- 9767789
TI - [Monitoring of the insulin treated diabetic].
PMID- 9767790
TI - [Radiation-induced rectitis, easy endoscopic diagnosis, an occasionally difficult
treatment].
PMID- 9767791
TI - ["Delorme" thickening of the rectal wall, a misleading ultrasound image].
PMID- 9767792
TI - [Broad-spectrum cephalosporins].
PMID- 9767793
TI - [Utilization of rapid diagnostic tests for group A streptococcus and and
bacteriologic and clinical correlations with acute angina in general medicine].
AB - OBJECTIVES: A prospective study was conducted between November 1995 and May 1996
by 130 general practitioners in France to assess feasibility of a rapid routine
diagnostic test for group A streptococcus infection in a general medicine setting
and to search for bacteriological and clinical correlations. METHODS: A routine
diagnostic test was performed in all patients presenting acute pharyngitis and
cultures were ordered in case of positive tests. Among the 2,800 patients
included, there were 563 children under 14 years and 2,226 adults. The routine
diagnostic test was positive in 393 cases (14%). A culture was obtained in 375
case and isolated group A streptococcus in 324 (11.5% of the total population).
The positive predictive value of the routine diagnostic test was 86.4% in this
general medicine setting. RESULTS: Comparing clinical signs with the results of
the routine diagnostic test showed that an erythematous pultaceous aspect of the
pharynx, severe dysphagia and the presence of enlarged nodes were more frequent
in patients with streptococcal pharyngitis. The association of these 3 clinical
signs with fever > 38 degrees C was also more frequent in patients with a
positive routine diagnostic test (OR = 3.3; 95% CI = 2.5-4.4). The triad
hoarseness + cough + rhinorrhea was more frequent in subjects with a positive
routine diagnostic test (22.7% versus 9%; OR = 2.6; 95% CI = 2.1-4.3).
CONCLUSION: The general practitioners who participated in this study found the
routine diagnostic test for group A streptococcal pharyngitis was easy to use and
compatible with everyday practice. This diagnostic tool was seen as a progress in
the management of acute pharyngitis, but only 53.7% of the practitioners were
willing to use antibiotics only for cases where a highly specific routine
diagnostic test performed during the consultation identifies group A
streptococcus. Lack of reimbursement by the national health assurance however
makes it impossible to use this test routinely in the general medicine setting.
PMID- 9767794
TI - [Procalcitonin, C-reactive protein and interleukin 6 in bacterial and viral
meningitis in children].
AB - OBJECTIVES: In young children with meningitis, blood or cerebrospinal fluid (CSF)
analysis cannot differentiate all cases of viral meningitis (VM) from bacterial
meningitis (BM). Empirical antibiotic therapy is often given. As new markers are
needed, we compared serum proCalcitonin (PCT) with CSF analysis for C-reactive
protein (CRP) and interleukin-6 (IL6). PATIENTS AND METHODS: PCT was measured
with a chemoluminescent assay in the sera of 23 children (aged 3 months to 14
years) hospitalized for BM and in 51 patients with VM. RESULTS: Initial CRP (mean
143.3 mg/l, range 28-351 and mean 13.9, range 1-48), CSF proteins (mean 2.2,
range 0.4-4.74 and mean 0.57, range 0.12-2.72) and white blood cell count in CSF
(range 240-17500 and 20-3200) in BM and VM respectively, were not sufficiently
discriminative to distinguish between BM and VM. Twenty-four of the 51 patients
with VM were given antibiotics. IL6 values at admission showed an overlap zone (>
100 pg/ml in 7/19 patients with VM and < 100 pg/ml in 1/8 patients with BM. PCT
was discriminative in all cases: mean PCT in BM was 61 micrograms/l (range 4.8
335) and 0.33 in VM (range 0-1.7; p < 0.001). No production of PCT was detected
in CSF. After antibiotic therapy, PCT decreased and reached undetectable levels
after recovery. CONCLUSION: PCT is a sensitive and specific marker for early
diagnosis of viral meningitis versus bacterial meningitis in children.
PMID- 9767796
TI - [Some pediatric associations].
PMID- 9767797
TI - [Community-acquired purulent meningitis in children].
PMID- 9767800
TI - [Childhood bacterial meningitis].
PMID- 9767798
TI - [Treatment with intravenous polyvalent immunoglobulins for autoimmune diseases in
children].
PMID- 9767795
TI - [Intracranial hypertension in a newborn treated with quinolone].
AB - BACKGROUND: Fluoroquinolones have not received administrative authorization for
use in children, but because of multiresistant pathogens in neonatal intensive
care, floroquinolones may be the only alternative. CASE REPORT: A premature
infant exclusively nourished by parenteral nutrition developed enterobacteria
sepsis. Ceftazidine was given initially but resistance led to the prescription of
fluoroquinolone. Signs of intracranial hypertension developed 3 days after onset
of fluoroquinolone treatment and regressed 48 hours after its withdrawal.
DISCUSSION: The main potential adverse effects with fluoroquinone in the newborn
are arthropathy, photosensitivity, discoloration of the teeth and neurological
disorders. Intracranial hypertension is a known complication of nalidixic acid
both in adults and children, but to our knowledge has not been previously with
floroquinolone in the newborn.
PMID- 9767799
TI - [Acute rheumatic fever in today's children].
PMID- 9767801
TI - [Childhood meningitis. Current data on physiopathology].
PMID- 9767802
TI - [Childhood bacterial meningitis. Bacterial epidemiology and antibiotic
resistance].
PMID- 9767803
TI - [Childhood bacterial meningitis. Antibiotic strategies].
PMID- 9767804
TI - [Childhood bacterial meningitis. Role of corticosteroids].
PMID- 9767805
TI - [Lytic epiphyseal-metaphyseal lesion].
PMID- 9767806
TI - [Severe pneumonia with a pneumococcal aspect during an ornithosis outbreak].
AB - OBJECTIVES: To describe the clinical, radiological and biological features of
Chlamydia psittaci pneumonia. METHODS: A pneumonia outbreak occurred in a healthy
middle-aged population working in a poultry slaughterhouse. Systematic serology
(2 samples at 5 weeks intervals) provided the diagnosis of Chlamydia psittaci
pneumonia in 6 patients. Patient files were analyzed retrospectively. RESULTS:
The clinical presentations in this series of pneumonia were particularly
homogeneous with a pneumococcal profile in all 6 cases: sudden onset, temperature
above 39 degrees C, lobar alveolar involvement, hypoxemia, hyperleukocytosis and
liver dysfunction. One case of hallucinatory delirium was observed. The patients
were given spiramycin (9 million units per day for 3 weeks) and all recovered
rapidly with no complications. CONCLUSION: The unusual virulence of the Chlamydia
psittaci and very important inoculum were probably involved in this outbreak
because of the severity of the pulmonary features and the short exposure of some
patients to the bacteria. These cases suggest that the prevention of ornithosis
in poultry slaughterhouses should be reinforced.
PMID- 9767807
TI - [Spontaneous positive end-expiratory pressure ventilation in elderly patients
with cardiogenic pulmonary edema. Assessment in an emergency admissions unit].
AB - OBJECTIVES: Intubation and ventilatory assistance are often required in patients
presenting severe hypoxemic respiratory distress, but may be contraindicated in
elderly subjects due to an underlying condition. The aim of this study was to
assess the feasibility, acceptability and contribution of early assistance with
spontaneous positive end-expiratory pressure ventilation for elderly subjects
admitted to an emergency unit for acute respiratory distress due to cardiogenic
pulmonary edema. PATIENTS AND METHODS: In our emergency admission unit, all
patients with life-threatening hypoxemic respiratory distress are initially
assisted with noninvasive spontaneous positive end-expiratory pressure
ventilation using a standardized commercial device. We retrospectively analyzed
the the files of all patients aged over 70 years who were treated with this
standard protocol for cardiogenic pulmonary edema from April 1996 through
September 1997. RESULTS: During the study period, 36 patients aged over 70 years
required ventilatory assistance according to the standard protocol. Intubation
was not reasonable in most of the patients (n = 30). After 1 hour of ventilation,
none of the patients developed clinical signs of life-threatening distress. Blood
gases demonstrated improved oxygenation (AEPO2 = +184.9 +/- 105.4 mmHg; p <
0.000001). Thirty-two patients were considered to be cured (88.9%) and were
discharged; the cardiovascular condition was fatal in 4 patients (11.1%).
CONCLUSION: The rapid improvement in clinical signs and blood gases as well as
the final outcome suggests that early assistance with spontaneous positive end
expiratory pressure ventilation is warranted at admission for elderly patients
with respiratory distress due to cardiogenic pulmonary edema. Compared with a
control group of hospitalized patients cared for during the preceding year and
who were not treated with the standard protocol, we also demonstrated a clear
improvement in mortality (11% versus 20%).
PMID- 9767808
TI - [Diabetes insipidus with a hypothalamo-hypophyseal morphologic anomaly during a
pregnancy].
AB - BACKGROUND: Diabetes insipidus is uncommon in pregnancy. Despite physiological
modifications in hydroelectrolytic balance during normal pregnancy, the capacity
of the kidney to concentrate urine is preserved, partially due to lower
vasopressin secretion. CASE REPORT: A young woman developed diabetes insipidus
during the third trimester of normal pregnancy. The disease regressed totally
after delivery. However, magnetic resonance imaging revealed a persistent
expansive intrasellar image with a high-intensity signal. DISCUSSION: Onset of
diabetes insipidus is usually rapidly progressive in pregnancy. Occurring
generally during the third trimester in normal pregnancies, diabetes insipidus is
generally well tolerated and responds to dDAVP, usually without pituitary
abnormally, and regresses after delivery. Two types are distinguished: partially
latent diabetes insipidus occurring during pregnancy and due to a central rather
than nephrogenic origin; and excessive vasopressinase activity leading to
diabetes insipidus usually associated with liver anomalies and high frequency of
pre-eclampsia. During normal pregnancy, the size of the anterior pituitary
increases and the normal high-intensity signal in the posterior pituitary seen on
MRI usually regresses or disappears. In diabetes insipidus, the posterior
pituitary hypersignal image generally disappears, reflecting reduced vasopressin
storage. Few observations of diabetes insipidus occurring during pregnancy have
been reported with morphological explorations. Most have described a "normal"
aspect of the pituitary, specifically in the post partum period. In our patient,
the weak vasopressin response to the end of water restriction at post partum when
the diabetes insipidus symptoms had disappeared would suggest partial central
diabetes insipidus revealed by pregnancy. Other pathologies involving this region
could also be involved due to the unusual and persistent sellar image, with an
expansive process showing a high intensity signal on MRI. An asymptomatic
craniopharyngioma cyst was hypothesized and would be more compatible with the
observed symptoms.
PMID- 9767809
TI - [Massive poisoning by African bee stings].
AB - BACKGROUND: Bee stings can cause severe toxic effects when envenomation is
massive. CASE REPORT: While touring in Casamance (Southern Senegal) a white male
was severely stung by a swarm of African bees. The massive envenomation caused
rhabdomyolysis, hemolysis and acute renal failure. Pathology examination of
kidney and bladder specimens showed vasculitis affecting both arteries and veins.
The patient was treated with several hemodialysis sessions and renal function
returned to normal three months after the incident. DISCUSSION: Bees in Africa,
known as "killer bees", are particularly aggressive. They have recently been
imported from tropical zones in America where a large number of deaths have been
reported. Most cases of massive envenomation have shown acute tubular necrosis or
renal involvement with myoglobinuria or hemoglobinuria. The renal pathology
observed in our case is not usually described.
PMID- 9767810
TI - [Sign of Lazarus after brain death].
PMID- 9767811
TI - [Iatrogenic aseptic meningitis].
PMID- 9767812
TI - [Parietal abdominal hematoma after combined acenocoumarol and roxithromycin
treatment].
PMID- 9767813
TI - [Relapsing Campylobacter coli bacteremia in a hypogammaglobulinemic patient].
PMID- 9767817
TI - [Endobronchial photodynamic therapy in France].
PMID- 9767814
TI - [Candida parapsilosis: an increasingly frequent cause of nosocomial fungemia].
PMID- 9767815
TI - [Use of non-invasive positive pressure ventilation for cardiogenic pulmonary
edema in emergency care units].
AB - The work reported by L'Her et al. in this issue of La Presse Medicale
demonstrates the feasibility of applying simple intensive care techniques in
situations frequently encountered in emergency care units. These authors used a
face mask for continuous positive pressure ventilation in patients over 70 years
of age admitted for respiratory distress related to cardiogenic pulmonary edema.
In these elderly patients, the authors noted an improvement in blood gases,
respiratory rate and heart rate and did not observe any secondary effect. Acute
respiratory failure was cured in 90% of the cases without referral to the
intensive care unit. The mechanism of action of continuous positive airway
pressure, or spontaneous ventilation with positive expiratory pressure, is
different from simple oxygen therapy. Two mechanisms are intimately related. The
main effect is ventilatory assistance resulting from a "re-aeration" of the
pulmonary parenchyma which increases compliance and reduces work required to
overcome elastic retraction forces. Likewise the increased pulmonary volume
reduces pulmonary resistance. Positive airway pressure also has an effect on left
ventricular function. Indeed, after-load is reduced by the reduction in the large
negative intrathoracic pressure swing. Lower energy expenditure required for
respiration also greatly reduces total oxygen consumption and improved blood
gases favor oxygen supply to the myocardium. The contraindications of continuous
positive airway pressure are related to abnormal control of the upper airways and
major hemodynamic disorders. Prudence is also required in case of shock due to
the risk of major respiratory muscle fatigue. The question could also be raised
as to the risk in elderly patients where cardiogenic pulmonary edema is often
associated with a certain degree of chronic bronchitis. It is now known that
these patients have an intrinsic positive expiratory pressure which considerably
increases respiratory work. Symptomatic treatment in this type of disorder is
mechanical and continuous positive airway pressure diminishes this work.
Cardiogenic pulmonary edema in the elderly is thus an excellent indication for
spontaneous ventilation with positive expiratory pressure. Improvement in these
simple techniques, their widespread use and a better understanding of their
limitations remain important challenges for the future.
PMID- 9767816
TI - [Von Hippel-Lindau disease: a hereditary disease that impacts multiple tissues].
PMID- 9767818
TI - [Late potentials in chronic alcoholics].
AB - OBJECTIVE: Cardiac arrest is the most frequent cause of death in chronic
alcoholics. Detection of late potentials in this population could be helpful in
screening from early signs of myocardial disorders and identifying patients at
risk of severe ventricular dysrythmia. PATIENTS AND METHODS: A prospective study
of late potentials was conducted in 53 subjects (mean age 49 +/- 10 years) with a
history of long-standing alcohol abuse (mean 13.6 +/- 8.5 years, mean daily
alcohol intake 86 +/- 30 g). After a period of abstinence, the following
explorations were performed: liver tests, liver biopsy, electrocardiogram,
echocardiography, Holter recording. RESULTS: Among the 53 patients, 37% were
positive for 2 of the 3 criteria for late potentials. There was a strong
correlation between the duration of alcohol abuse and presence of late potentials
(p = 0.006, r = 0.37). The percentage of hepatic steatosis was higher in
alcoholic subjects with late potentials (34% versus 23%; p = 0.05) and was
correlated with the number of positive criteria for late potentials (p = 0.05, r
= 0.328). Finally, the presence of late potentials was also correlated with the
following laboratory results: serum gamma glutamyltranspeptidase (p = 0.031),
serum aspartate amino transferase (p = 0.033), serum alkaline phosphatases (p =
0.0025). CONCLUSION: Late potentials can be detected easily although their
prognostic value remains to be determined. They could be an early marker of
infraclinical myocardial lesions.
PMID- 9767819
TI - [Prognosis after myocardial infarct in a diabetic patient: results of coronary
intensive care unit epidemiological study].
AB - OBJECTIVE: Determine early and mid-term mortality in diabetic patients with
myocardial infarction and ascertain whether diabetes is an independent prognosis
factor. PATIENTS AND METHODS: All patients admitted to an intensive care unit
within 48 hours of the first signs of myocardial infarction were included in the
study. Diabetic status was recorded at admission. Early mortality (5 day) and 1
year mortality was compared between diabetic and non-diabetic patients.
Multivariate analysis was used to determine the predictive value of diabetic
status as an independent factor. RESULTS: 2527 patients, including 440 diabetics
(17%) and 2087 non-diabetics (83%) were followed at 5 days; 2125 patients,
including 364 diabetics (17%) and 1761 non-diabetics (83%) were followed to 1
year. Diabetes was more frequent in older patients and in women. Mortality in
diabetic patients was higher than in non-diabetics. At 5 days, mortality was
10.4% versus 17.6% (p < 0.001). Multivariate analysis did not confirm diabetic
status as an independent risk factor for death at 5 days. Inversely, at 1 year,
diabetic status was an independent risk factor (RR = 1.4; 95% CI = 1.1 -1.8; p =
0.004). CONCLUSION: Diabetes is associated with poor prognosis after myocardial
infarction. After correction for other risk factors, diabetes is an independent
risk factor which must be taken into account when managien after myocardial
infarction.
PMID- 9767820
TI - [Lactobacillus acidophilus endocarditis].
AB - BACKGROUND: Lactobacillus is a commensal germ found in the buccal cavity, the
digestive tract and the vagina. Usually non-pathogenic except in case of dental
caries, it can occasionally be the causal agent in severe endocarditis. CASE
REPORT: A 70-year-old woman developed endocarditis on an aortic valve
bioprosthesis. Lactobacillus acidophilus was isolated from blood cultures of the
valve after surgery. COMMENTS: Forty-four cases of Lactobacillus endocarditis
have been reported in the literature to date. Mortality is high (26%). The main
difficulty in treatment is germ tolerance to penicillin and aminosides found in
all cases. Cure requires high dose parenteral antibiotics and surgery in many
cases (26%).
PMID- 9767821
TI - [Migration of a clavicular bone wire acutely perforating the ascending aorta].
PMID- 9767823
TI - [Hemodialysis of the elderly patient: consider the coronary arteries].
PMID- 9767822
TI - [Quality and accreditation in health facilities].
PMID- 9767824
TI - [Specifically adapted management of diabetics after myocardial infarct].
AB - Approximately 20% of all patients hospitalized for myocardial infarction have
diabetes. The percentage has been increasing constantly and mortality is
significantly higher in these patients. The highest rate is observed in women.
Despite continuing progress in patient management there has been no reduction in
the overmortality after myocardial infarction in diabetic patients. The majority
of these deaths are unwarranted and could be avoided if diabetic patients were
given specifically adapted treatment after myocardial infarction. Unfortunately,
as shown by the EURASPIRE study, there is a gap between intensive care unit
discharge prescriptions and follow-up care. With the explosive "epidemic" of
noninsulin-diabetes and population aging the number of patients with coronary
artery disease and diabetes will rise in the future. Wouldn't it be reasonable to
establish special cardiodiabetic units where such patients could benefit from
close, and daily, cooperation between diabetologists and cardiologists? Such
facilities could be expected to significantly reduce the overmortality in
diabetic patients after myocardial infarction.
PMID- 9767825
TI - [Prevention of bacterial endocarditis. New recommendations from the American
Heart Association].
PMID- 9767826
TI - [Congenital long QT syndrome].
AB - SEVERAL FORMS: Congenital long QT syndrome is a clinically (with and without
deafness) and genetically (recessive or dominant autosomal inheritance)
heterogeneous entity characterized by a long QT interval on the ECG associated
with the risk of severe ventricular arrhythmia (torsade de pointes, ventricular
fibrillation) and subsequent syncope or sudden death. GENETIC DATA: This rare
familial syndrome is transmitted by different modes of inheritance and occurs in
subjects with a morphologically normal heart. The severity of the prognosis
justifies screening tests. The genetic origin of the disease has been confirmed
and at least 5 loci and 4 genes have been identified, giving a perfect
illustration of adrenergic ventricular rhythm disorders. Beta-blockers are used
as first line treatment in symptomatic patients. PREVENTION: All drugs favoring
QT interval lengthening are contraindicated in all subjects with a genetic
anomaly. All members of the direct family must have a Holter recording and
genotype in order to identify mutation carriers or asymptomatic patients.
PMID- 9767827
TI - [Myocardial viability. The concept of myocardial viability].
AB - MYOCARDIAL VIABILITY: Certain zones of ischemic, akinetic or severely hypokinetic
myocardium are capable of recovering normal contractile function. This is termed
myocardial viability and occurs in two different situations: myocardial stunning
and myocardial hibernation. MYOCARDIAL STUNNING: This term designates temporary
but prolonged impairment of myocardial function resulting from a brief episode of
ischemia before reperfusion. MYOCARDIAL HIBERNATION: Hibernation designates
prolonged but potentially reversible myocardial contractile dysfunction caused by
chronic myocardial ischemia and persisting at least until blood flow is restored.
CLINICAL CONSEQUENCES: Theoretically reversible, myocardial stunning or
hibernation can have devastating effects if they persist too long.
Revascularization with angioplasty or bypass surgery is indicated. DIAGNOSIS: The
degree of myocardial viability in akinetic zones can be determined by assessing
preserved inotropic capacity with stress echocardiography and/or evidencing
metabolic activity with isotopic techniques (myocardial scintigraphy, positron
emission tomography).
PMID- 9767828
TI - [Myocardial viability. Study of viability by myocardial scintigraphy].
AB - FUNDAMENTAL PRINCIPLES: Myocardial scintigraphy is a metabolic approach to
myocardial viability visualizing the localization, the extent and to some degree
the quantity of non-functional yet viable myocardial tissue. Potential for
functional recovery cannot be ascertained directly from the scintigram but can be
inferred from commonly observed behavior after blood flow has been restored.
Myocardial scintigraphy is thus fundamentally different from other functional
exploration methods such as echocardiography or nuclear magnetic resonance
imaging which can detect residual contractile capacity unmasked by inotropic
stimulation. It must be remembered however that such 'forced' contractility may
not necessarily be expresses spontaneously after revascularization and that,
however detected, truly viable myocardium may not recover normal contractility
after reperfusion when associated with non-transmural infarction or diffuse
fibrosis. PET AND THALLIUM 201 SCANS: Positron emission tomography (PET) is the
gold standard. Accomplished after administration of an isotope labeled substance
(18-fluoro-deoxyglucose, FDG), the PET scan visualizes metabolic activity in
viable myocardium. Special equipment is however required and facilities are
limited, particularly in France. Thallium 201 scans can be acquired with
conventional gamma cameras and protocols have been widely developed with nearly
equivalent performance in certain situations of doubtful residual viability after
post-infarction thrombolysis or angioplasty. It must be noted however that in
such cases, search for homolateral or contralateral ischemia may be the main
objective rather than the detection of residual viability. A 3-step thallium 201
scintigraphy protocol with stress, 4-hr redistribution then imaging after
reinjection is usually sufficient to document ischemia or viability warranting
revascularization. The problem is quite different for patients with major
myocardial dysfunction and histological remodeling due to hypokinetic dilated
cardiomyopathy. In such types of myocardium, chances of recovering inotropic
capacity are quite limited and detecting viable tissue would be technically
difficult; however with a proper protocol (without stress, resting images late
after injection), thallium 201 scintigraphy can be helpful. PERFORMANCE: Data in
the literature shows that isotopic techniques lack specificity by overestimating
the extent of viable tissue capable of recovering contractility. Actually this
could be seen as an advantage since the consequences of missing even a small
chance for revascularization warrant risking an ineffective procedure for a
patient whose only alternative is heart transplantation. This situation explains
why 18-FDG PET exploration should be performed even if the thallium scintigram
leaves very little room for hope of recovering viable myocardium in patients with
terminal disease. PERSPECTIVES: Isotopic exploration of the myocardium is a
moving field and routine practice can expect to benefit from research conducted
in pioneer centers. The future offers two main perspectives: the development of
metabolic tracers giving more precision than thallium 201 (for example isotope
labeled fatty acids); and technical advances in conventional gamma cameras more
adapted to the physical characteristics of 18 FDG used for PET scans.
Scintigraphy is an indispensible tool for metabolic exploration of the
myocardium. Only nuclear magnetic resonance spectroscopy may provide comparable
results.
PMID- 9767830
TI - [Nitric oxide (NO), vascular protection factor. Biology, physiological role and
biochemistry of NO].
AB - VASOMOTRICITY: The vascular endothelium plays a key role in vasomotricity by
producing a number of factors which modulate smooth muscle relaxation and
contraction. Nitric oxide (NO) has been found to be one of the most important
relaxation factors. NO SYNTHESIS: Nitric oxide is synthesized from L-arginine by
NO-synthetase whose activity is regulated by intracellular calcium concentration
and modulated by pharmacological compounds such as acetylcholine, 5
hydroxytryptamine, bradykinin and ADP as well as the sheer forces produced by
blood flow. MODE OF ACTION: NO stimulates soluble guanylate cyclase in smooth
muscles. Its action is mediated by increased intracellular cGMP which provokes
smooth muscle relaxation. ACTIONS OF NO: The physiological role of NO produced by
the vascular endothelium is quite complex and incompletely elucidated. NO helps
maintain adequate blood supply to tissues by reacting rapidly to changes in
pharmacological and mechanical stimuli. It opposes the direct vasoconstrictor
effect of certain factors in the blood stream and its action on platelets and
endogenous fibrinolysis helps prevent thrombus formation.
PMID- 9767829
TI - [Myocardial viability. Myocardial viability post-infarct: contribution of
dobutamine-echography].
AB - ROUTINE EXPLORATION: Echocardiography during dopamine perfusion has been widely
proven as an effective tool for determining myocardial viability. Dobutamine has
marketing authorization in France for stress-echocardiography and is widely used
in clinical practice outside research protocols. The exploration must however be
conducted within an appropriately equipped cardiac intensive care unit. Stress
echocardiography has certain advantages over isotropic techniques, in terms of
equipment costs, examination time and exposure to isotopes. POST-INFARCTION:
Dobutamine-echocardiography enables detection of viable myocardium within the
infarct zone, evaluates the degree of residual ischemia in the infarct zone and
provides information on prognosis. It would not however be reasonable to perform
stress-echocardiography as a first line exploration after infarction.
International guidelines recommend a sub-maximal ECG exercise test prior to
coronarography. The contribution of stress-echocardiography after infarction is
its ability to give precise information on myocardial viability and residual
ischemia in one or more territories to compare with coronary lesions, thus
allowing indication for revascularization. CHRONIC ISCHEMIC CARDIOPATHY:
Dobutamine-echocardiography can be used to detect hibernating myocardium in
patients with chronic ischemic cardiopathy. In this indication, the sensitivity
of stress-echocardiography is slightly lower than thallium scintigraphy, but its
specificity and positive predictive values are higher. The best predictive value
is obtained with bimodal dobutamine-echocardiography: improve-med thickening at
low doses and a degradation at high dose is predictive of functional improvement
after revascularization in 72% of the cases. In more severe cases with ejection
fraction < 35%, improvement in hibernating myocardium after revascularization
leads to a significant improvement in left ventricular ejection fraction.
PMID- 9767831
TI - [Nitric oxide (NO), vascular protection factor. NO related cardiovascular
diseases].
AB - ALTERATIONS OF THE ENDOTHELIUM: Because of its anatomic position between
circulating blood and smooth muscle cells, the vascular endothelium is a prime
target for cardiovascular diseases such as hypertension, hypercholesterolemia,
diabetes or ischemia. The morphological changes occurring in the endothelium have
been known for many years, but it was only recently that the functional
alterations have been described. IMPACT OF NO: Under physiological conditions,
the vascular endothelium plays a protective role by secreting relaxation factors.
In the disease state, the synthesis and release of NO may be reduced or even
abolished. The exact significance of endothelium-dependent vasodilatation
disorders remains a topic of research, but the properties of NO strongly suggest
it is involved in several diseases. For some diseases it is still a question as
to whether the observed anomalies are the cause or the consequence of the
underlying disease. DISEASE-SPECIFIC CHANGES: NO is known to be reduced in
atherosclerosis, either because of less synthesis or accelerated degradation. In
different experimental modules of hypertension, the baseline level of NO release
appears to be decreased. Conversely, NO release can be normal, reduced or
increased in diabetes. In heart failure, there appears to be not only a permanent
alteration in NO secretion, but also an increase in factors stimulating vascular
contraction, contributing to an altered capacity for vascular adaptation in these
patients.
PMID- 9767833
TI - [Ascending aorta dissection. Transesophageal color doppler ultrasonography].
PMID- 9767834
TI - [Prevalence and incidence of cytomegalovirus infection in patients infected with
HIV-1. SEROCO group].
AB - OBJECTIVES: To study prevalence of the cytomegalovirus (CMV) infection as well as
incidence of the CMV seroconversions in HIV-infected subjects enrolled in the
French multicentric cohort SEROCO. METHOD: Prevalence of CMV infection at
inclusion in the cohort was estimated from 1504 HIV-infected subjects. Incidence
of the CMV seroconversion was estimated from 184 subjects CMV seronegative at
inclusion. Cox model was used to identify independent factors related to CMV
seroconversion. RESULTS: CMV prevalence was high (87.2%) mainly in homosexual
men. The incidence of the CMV seroconversions was also high (9, 18/100 person
years), particularly in homosexual men, in subjects declaring sexual intercourse
with occasional partner, and in those declaring a sexually transmitted disease
during the follow-up. CONCLUSION: The risk to develop serious disease related to
CMV in subjects with AIDS being particularly high when the CMV primary infection
occurs during the course of the HIV infection, the prevention of CMV primary
infections is thus a major element in the counselling of HIV-infected subjects.
PMID- 9767835
TI - [Aorto-coronary bypass].
AB - OBJECTIVES: Saphenous grafts used for coronary artery bypass are classically
dissected via a continuous incision of the leg, the thigh or both. Recently, a
new video-surgery technique has been introduced in an attempt to reduce the
trauma of saphenous vein dissection. The aim of this work was to evaluate the
possible benefits of this new technique compared with classical dissection.
PATIENTS AND METHODS: Sixty patients requiring coronary artery bypass grafts were
included in this study and randomly divided into two groups. In group I (30
patients) the saphenous vein was dissected according to the classical technique.
The video-surgery technique was used for the other 30 patients in group II. The
two groups were not significantly different for mean age, sex ratio, or history
of diabetes or lower limb arteriopathy. The same number of bypasses was performed
in both groups (2.6 +/- 0.7). Outcome was compared for: dissection related
complications (hematomas, infections), length of the skin incision over the
length of the dissected vein, duration of the dissection procedure, and post
operative pain. RESULTS: A leg incision was used in 28 cases out of 30 cases in
both groups. The length of the saphenous vein dissected was 27.6 cm in group I
and 21.8 cm in group II. The length of the skin incision was 27 cm in group I and
only 4.7 cm in the video-surgery group II, giving an incision/vein ratio of 97%
and 21% respectively. Operative time was however 37.9 min for group I and 48.5
min for group II. There was no significant difference between the groups for
hematoma formation or infection but the patients in the video-surgery group
experienced less post-operative pain. CONCLUSION: Besides an improvement in the
esthetic result, video-surgery dissection of the saphenous vein reduces post
operative pain at the cost of a slightly longer operative procedure.
PMID- 9767832
TI - [Nitric oxide (NO), vascular protection factor. NO: role in aging].
AB - AGING PROCESS: There is a large body of experimental and clinical data
demonstrating that endothelial dysfunction is encountered not only in disease
states such as atherosclerosis, hypertension, heart failure or diabetes, but also
in the normal physiological process of aging. Currently available data show that
endothelium-dependent function declines with age. The fact that this same decline
is observed in patients with hypertension suggests that age is an independent
factor capable of provoking changes in the vascular endothelium. CAUSAL
MECHANISMS: It is often suggested that altered NO synthesis from L-arginine
and/or increased production of contraction factors play a role in the aggravation
of endothelial and parietal lesions and would thus affect the natural history of
the disease process. HUMAN STUDIES: Ongoing studies in man tend to confirm
experimental data obtained in animal models; treatment protocols could be adapted
using compounds aimed at restoring normal endothelial function.
PMID- 9767836
TI - [Cerebral and pulmonary miliary tuberculosis in an immunocompetent patient:
aggravation in an adequately treated patient].
AB - BACKGROUND: Extrapulmonary localizations are observed in 20% of tuberculosis
cases, mainly in immunosuppressed patients. Prognosis is poor in case of
relatively uncommon cerebral localizations and miliary dissemination, especially
if treatment is initiated in late stages. We report a case of disseminated
tuberculosis associated with cerebral and pulmonary localizations in an
immunocompetent patient. THe disease progressed despite adapted treatment. CASE
REPORT: A young immunocompetent man with an uneventful history developed miliary
tuberculosis with pulmonary localizations visualized on the computed tomography
(CT) of the thorax. Brain CT was normal, but magnetic resonance imaging revealed
several intracranial lesions. The disease course was marked by development of
neurological symptoms and progression of the cerebral lesions after one month of
treatment. No evidence of therapeutic failure (insufficient dosing, non
compliance, primary resistance) could be identified. DISCUSSION: Magnetic
resonance imaging provides a more precise evaluation of tuberculosis lesions in
the brain. Early antituberculosis therapy associated with corticosteroids can
improve prognosis. Clinicians should be aware that cerebral lesions may continue
to progress despite appropriate treatment, a course which is not satisfactorily
explained by any current pathogenic hypothesis.
PMID- 9767839
TI - [Hypersensitivity vasculitis after hepatitis B vaccination].
PMID- 9767838
TI - [Portal thrombosis and anticardiolipin antibodies association in an HIV-2
infected patient].
PMID- 9767837
TI - [Diffuse digestive tract B-cell lymphoma manifesting as exudative enteropathy].
AB - BACKGROUND: Early manifestations of primary lymphomas of the digestive tract
generally include general signs and abdominal pain. Diarrhea is uncommon and may
result from several mechanisms. We report a case of primary lymphoma of the
digestive tract in a patient presenting exsudative enteropathy. CASE REPORT: A 68
year-old woman was hospitalized for profuse diarrhea of 15 days duration.
Laboratory tests showed major hypoalbuminemia. Malabsorption could not be
evidenced and no infectious foyer was found. Biopsies at different levels of the
digestive tract showed mucosal invasion by MALT type B-cell lymphoma. The
clinical course was initially favorable after chemotherapy. DISCUSSION:
Classification of digestive tract lymphomas differentiates MALT type B-cell
lymphoma (the most frequently encountered type in western countries),
Mediterranean lymphomas, and T-cell lymphomas generally complicating coeliac
disease. MALT type lymphomas may occur in association with Helicobacter pylori
infection, usually in a gastric localization. Multiple localizations are uncommon
and diffuse involvement of the digestive tract as in our observation appears
exceptional. This extension would explain the exsudative enteropathy which
regressed with chemotherapy.
PMID- 9767841
TI - [Unique cerebral metastasis of ovarian origin].
PMID- 9767842
TI - [Cystic form of bronchopulmonary cancer associated by a malignant non-Hodgkin
lymphoma].
PMID- 9767840
TI - [Lupus erythematosus probably induced by carbamazepine, associated with
complement fraction deficiency].
PMID- 9767844
TI - [Cervical-vaginal smears: an unpopular test!].
AB - No screening test for cancer in asymptomatic patients can match the performance
level of the Pap smear, yet no other screening test has been so strongly
criticized in the popular press. For a large part, this paradoxical situation,
greatly influenced by public opinion in the United States, has arisen from a
utopic desire for a "perfect" screening system. Actually, though the Pap smear
will never be 100% effective, it has made it possible to greatly reduce the
prevalence of invasive cervical cancer. The fact that total eradication has not
been achieved is not a sign of poor performance, but rather a signal for further
improvement. Public education should be reinforced so the entire population,
especially high risk groups of older women and those living in socially
underprivileged conditions, can benefit from Pap smear screening programs.
Clinicians and cytologists must also continue their efforts to assure quality
smears and cytopathological examinations. In France, the Association for quality
assurance in anatomy and pathological cytology, the Centers for collecting
information on anatomy and pathological cytology, and the High Counsel for Public
Health have taken innovative steps in this direction. The cytology report must
also be written in a clear language, including a statement regarding the adequacy
of the specimen, the description of the cells observed, a diagnosis and the use
of an internationally accepted classification. Finally, patient follow-up is
mandatory since the Pap smear technique is a screening method and cannot provide
a definitive diagnosis. All positive smears must be confirmed by colposcopy and
histologic assessment. Correctly used, the Pap smear remains the method of choice
for the eradication of cervical cancer.
PMID- 9767843
TI - [Teaching ethics in French medical schools: evolution or revolution ?].
AB - Ethics was introduced as subject matter in French medical schools only recently
despite a rich historical context where scientific legitimacy, humanistic
exigencies and anglo-saxon influence have all played a role. Ten years after the
thesis presented by Bastian in 1986, a survey of French medical schools shows
that ethics has become an integral part of the curriculum. Ethics has tended to
become a discipline on its own, separate from law and deontology. However, the
lack of specific courses on concentration in the first years of the curriculum
show that there is much room for growth in the discipline of medical ethics.
PMID- 9767846
TI - [Intensive therapy in non-Hodgkins lymphoma. Indications and modalities].
PMID- 9767845
TI - [Diagnosis of pulmonary embolism: value of imaging].
PMID- 9767847
TI - [Peptic esophagitis and Barrett's esophagus: two often associated complication of
hiatal hernia].
PMID- 9767848
TI - [Nosocomial infections in intensive care].
PMID- 9767851
TI - [Cerebral abscess during a severe form of Salmonella typhimurium bacteremia in an
immunocompetent patient].
AB - BACKGROUND: Bacteremia rarely occurs in non-typhoid salmonella infections and the
development of a brain abscess is exceptional. CASE REPORT: An immunocompetent
patient developed severe Salmonella typhimurium bacteremia leading to septic
shock and acute respiratory distress and acute renal failure. A brain abscess,
which was not present on the initial brain tomodensitometry, developed and
totally regressed after antibiotic therapy. DISCUSSION: We were unable to
identify and factor favoring the development of salmonella bacteremia in this
patient. There were no cerebral lesions on the initial brain tomodensitometry
considered to be normal. To our knowledge, this is the first report of Salmonella
typhimurium brain abscess in an immunocompetent subject.
PMID- 9767849
TI - [Vitamin D status in aged subjects. Study of a Lebanese population].
AB - OBJECTIVES: To evaluate vitamin D status in two subgroups of the Lebanese aged
population. To compare results with reference values observed in healthy young
volunteers. METHODS: Fifty aged institutionalized patients (25 men and 25 women)
and 51 aged ambulatory subjects (25 men and 26 women) underwent the following
explorations during winter: serum 25-OH vitamin D, parathyroid hormone, corrected
serum calcium, phosphorus, creatinine, and alkaline phosphatases and urinary
calcium/creatinine. Serum 25-OH vitamin D and urinary calcium/creatinine were
also measured in 34 healthy young volunteers. RESULTS: Serum 25-OH vitamin D
levels in 25 ambulatory subjects (49%) and 30 institutionalized patients (60%)
were below 10 ng/ml. There was non significant difference in 25-OH vitamin D
levels between the ambulatory and institutionalized aged populations, nor between
aged women and aged men. Parathyroid hormone, alkaline phosphatases and urinary
calcium/creatinine levels were higher in the institutionalized population than in
the ambulatory population (p = 0.07; p = 0.0001; p = 0.0001 respectively). Aged
women had higher parathyroid hormone and calcium/creatine levels than aged men (p
= 0.005; p = 0.005 respectively). Finally, in the young population, 25-OH vitamin
D was higher than in the aged institutionalized and ambulatory populations (p =
0.0001 and p = 0.0009 respectively). An inverse non-significant correlation (r =
0.16) was found between parathyroid hormone and 25-OH vitamin D. CONCLUSION: Our
results show that even in a sunny country like Lebanon, vitamin D deficiency is
often observed. The degree of deficiency probably lies between that observed in
Europe and the United States. It could be related to low vitamin D diet.
PMID- 9767850
TI - [Initial antiretroviral prescriptions in patients with HIV. Second semester 1994
second semester 1996].
AB - OBJECTIVES: The nature of antiretroviral therapy has radically changed these last
years. A study has been conducted on data obtained from the DMI2 information
system to evaluate changes on treatments, immunity and transmission profile of
the patient naive to antiretroviral therapy when initiating a therapy. METHODS:
DMI2 is a national, multicentered database which contains medical,
epidemiological and economic information on hospital care for HIV patients. This
study, on 18,510 patients followed up in one of the fifty hospitals belonging to
the Centers for Information and Care of Human immune Deficiency, was conducted
from the second half of 1994 to the second half of 1996. RESULTS: The therapeutic
changes seen on the whole seropositive population are also observed on these
patients: the proportion of regimen with only one nucleoside analogue have
decreased from 90.2% in 1994 to 7.5% in 1996. The proportion of treatment with
two nucleoside analogues increased from 7.9% to 67.6%. The proportion of two
nucleoside analogues with one protease inhibitor regimen increased from 1.9% in
1994 to 24.6% at the end of 1996. A study focused on the second semester of 1996
shows that the proportion of homo-bisexual patients initiating an antiretroviral
treatment with a three antiretroviral agents combination (29.7%) is greater than
the one in the IVDU group (20.4%) or in the heterosexual group (20.8%).
CONCLUSION: These results show that a higher number of patient naive to the
antiretroviral therapy initiate therapy earlier, with a two or three agents
combination preferentially and at a better stage of immunity.
PMID- 9767853
TI - [Fish egg poisoning (genus Barbus): experience at the Marseille and Paris Poison
Control Centers].
PMID- 9767852
TI - [Breast adenocarcinoma and sarcoidosis: a fortuitous association?].
PMID- 9767854
TI - [Severe hypercorticism due to opiate withdrawal].
PMID- 9767855
TI - [Hemobilia of gallbladder origin manifesting as malignant hypertension].
PMID- 9767856
TI - [Inflammatory breast metastasis from cancer of the ovary].
PMID- 9767859
TI - [Arthritis after intravesicular BCG therapy].
PMID- 9767858
TI - [Treatment of lead poisoning].
PMID- 9767857
TI - [Transcranial Doppler: value in the detection of right-left shunt in scuba
divers].
PMID- 9767860
TI - [Infectious spondylodiscitis after peridural infiltration of prednisolone].
PMID- 9767861
TI - [The concept of therapeutic management: exemplary implementation of
antiretroviral treatments].
AB - Since the discover of AIDS in 1981 and the causal human immunodeficiency virus in
1983, therapeutic strategies have gone through many phases. When the ACTG 175 and
Delta trials demonstrated the clinical improvement offered by regiments combining
2 nucleosides over monotherapy, combination therapy was being prescribed for less
than 20% of all primary infections. Less than one year later, this rate suddenly
rose to 90%. At the same time, the clinical benefit in terms of reduced morbidity
and mortality was demonstrated for triple therapy and by the end of 1997, 65% of
all treated HIV+ patients were taking the triple combination therapy, 34% were on
bitherapy and only 1% on single drug regimens. This fantastically rapid evolution
of management strategies appears even more exceptional when one realizes that
these changes in prescription attitudes took place before expert groups were able
to establish accepted guidelines. The number of patients under treatment also
rose sharply from 57% in early 1994 to 87% in late 1997, while the number of
active hospital files rose by 30%. These rapid changes in patient management
schemes has had a major effect on HIV-related morbidity and mortality. In 1997,
the number of deaths fell by 41% and the number of new AIDS cases by nearly 50%.
The number of hospitalizations has also declined by 50% over the last 2 years.
This is probably the first time in the history in medicine that preliminary
clinical studies have led to direct patient benefit in so short a time. This
achievement has been accomplished by the combined efforts of health care workers,
patient associations, public authorities and the pharmaceutical industry. This
global view must not however hide the fact that most all the prescriptions used
today are based on the results of clinical trials in a small number of patients
over short study periods. Long-term efficacy and tolerance remain unknown. One
must also keep in mind one other figure which has not varied over this period.
The percentage of new AIDS cases in patients no ith no prior treatment because
they are unaware of the infection or because they do not want treatment remains
unchanged at 40%.
PMID- 9767863
TI - [Methods of investigation in pulmonary infections].
PMID- 9767862
TI - [Pulmonary infections in immune deficiency states. Immunosuppression and its
consequences].
PMID- 9767864
TI - [Pulmonary infections during AIDS].
PMID- 9767865
TI - [Pulmonary infections other than AIDS].
PMID- 9767866
TI - [Pseudo-thrombosis of the inferior vena cava].
PMID- 9767867
TI - [Anterior uveitis in HIV-infected patients. 3 cases in patients treated with an
antiprotease].
AB - OBJECTIVES: Uveitis is an ocular manifestation rarely observed in HIV-infected
patients. We observed three cases of anterior uveitis without progressive
retinitis in HIV patients receiving antiprotease treatment. CASE REPORT: The
first patient developed a first episode of uveitis during ritonavir therapy. Two
other episodes occurred with indinavir. The second patient developed uveitis when
treated with indinavir. In the third patient, the first episode developed with
indinavir and a second with a ritonavir-saquinavir combination. Uveitis was
unilateral in 4 episodes. Clinical manifestations were red irritable eyes and, in
2 episodes, reduced visual acuity. The antiprotease was interrupted in 4 of the 6
episodes and clinical course was rapidly favorable. DISCUSSION: Pure anterior
uveitis should suggest drug induction in HIV infected patients; rifabutin is
often the cause. Infectious causes predominate in case of total uveitis
associating choroid and retinal involvement. Cytomegalovirus, herpes zoster,
syphilis, and toxoplasmosis have been incriminated. Antiproteases would appear to
be a new cause of anterior uveitis in HIV-infected patients.
PMID- 9767869
TI - [Leiomyosarcoma of the inferior vena cava].
AB - BACKGROUND: The inferior vena cava is an uncommon location for leiomyosarcoma, a
malignant tumor which develops from the smooth muscle tissue of the media. CASE
REPORT: A 76-year-old woman was hospitalized for swelling of the lower limbs.
Ultrasonography, computed tomography of the abdomen and magnetic resonance
imaging showed tumoral invasion of the inferior vena cava extending to the
atrium. Histology examination of a tumoral fragment obtained by transjugular
catheterism affirmed the diagnosis of leiomyosarcoma. DISCUSSION: Prognosis of
leiomyosarcoma of the inferior vena cava is very poor. No medical or surgical
treatment has given satisfactory results. Two factors would explain the poor
prognosis: the tumoral localization and the low degree of tumoral
differentiation. Clinical presentation and imaging findings suggest the diagnosis
which must be confirmed by pathology examination of a tumoral biopsy specimen.
PMID- 9767868
TI - [The importance of lipoprotein(a) as a predictive factor of coronary
atherosclerosis].
AB - OBJECTIVE: The predictive value of lipoprotein(a), Lp(a), for coronary artery
disease, is strongly suspected, though unproven. The normal serum level is 0.3
g/l. We searched for correlations between serum Lp(a) levels and coronary artery
disease in a population of patients hospitalized in a general cardiology unit.
METHOD: Serum Lp(a) was assayed in all patients consecutively hospitalized during
1994 in the Valence hospital cardiology unit. Two groups were distinguished:
patients with coronary artery disease (n = 444) and those presumed free of
coronary artery disease (n = 555). Coronography were performed when required.
Serum Lp(a) levels were compared for the following variables: age, sex, smoking
habits, blood pressure, total cholesterol, HDL and LDL-cholesterol, triglycerides
and apolipoproteins A1 and A2. Univariate, then multivariate analysis were
performed first patients of all ages, then for those aged more and less than 60
years. RESULTS: Univariate analysis demonstrated that Lp(a) > 0.3 g/l was
associated with coronary heart disease (OR = 1.33; p = 0.03), although this
correlation was no longer significant after adjustment for other known risk
factors (OR = 1.28; p = 0.07), except in the subgroup of patients over 60 years
of age (OR = 1.37; p = 0.04). CONCLUSION: There was a non-significant trend
favoring an association between serum Lp(a) level > 0.3 g/l and the development
of coronary artery disease.
PMID- 9767871
TI - [The major response of metastatic kidney cancer to the combination of
oxaliplatin, 5-fluorouracil and folinic acid (FOX-FOL)].
PMID- 9767870
TI - [Small intestine metastasis of a melanoma].
PMID- 9767872
TI - [Cutaneous leukocytoclastic vasculitis in a patient with pulmonary tuberculosis].
PMID- 9767874
TI - [The prescription of serum tumor markers in a general hospital].
PMID- 9767873
TI - [Severe hypercalcemia in a patient treated with fluconazole and rifampicin].
PMID- 9767877
TI - [Digestive disorders: improving the accuracy and safety of tests].
PMID- 9767875
TI - [On the value of research on retinal cholesterol embolism].
PMID- 9767876
TI - [Xenografts: clinical trials and perspectives].
AB - Despite the reticence of certain prominent scientists, there will be no
moratorium on clinical xenotransplantation in the USA and a limited number of
well-controlled trials will be enabled. There has already been some advances in
cell and tissue xenografts with encapsulated porcine pancreas cells and porcine
foetal neurones in patients with diabetes and Parkinson's disease. However,
because of some porcine viruses are able to develop in human tissues, current and
planned trials have been interrupted until routine viral detection tests are
available. Several attempts have been made in the past, with animal organs
(kidney, heart, liver) from various non-human primate species and conventional
immunotherapy without success. Another major question now, is the choice of the
animal donor species. Phylogenetically dose to man, non-human primates would be a
right and logical choice. But, because of their procurement problems, it is
likely that most future trials will be conducted with porcine organs from more
performant transgenic animals, more powerful immunosuppressors and new
therapeutic strategies based on the natural tolerance mechanisms.
PMID- 9767878
TI - [Transmission modes of hepatitis C virus].
AB - SITUATION IN FRANCE: The prevalence of hepatitis C virus (HCV) infection in the
French population is estimated at 1%, a level similar to that in other western
countries. USUAL CONTAMINATION ROUTES: Epidemiological studies, together with
gene typing, have made it possible to distinguish transmission modes. A history
of intravenous drug abuse or transfusion is found in 60 to 80% of all subjects
infected by the HCV. Other documented modes of contamination include
hemodialysis, organ transplantation, accidental occupational-related puncture and
mother-infant transmission. OTHER ROUTES: Sexual or intra-familial nonsexual
transmission is uncommon and related to the length of exposure and the stage of
HCV infection in the "source" subjects. Cases of HCV transmission have been
reported during medical procedures. Currently the mode of of transmission is
unknown in 20 to 40% of the cases.
PMID- 9767881
TI - [Intrathoracic gossypiboma].
PMID- 9767879
TI - [Reversible bronchial spasm syndrome in the very old].
AB - HIGH PREVALENCE: Several epidemiological studies have shown that the prevalence
of bronchial asthma is high in the elderly. It is often difficult to establish
the diagnosis of asthma in this population because of the scarcity of symptoms.
Pulmonary function tests are widely used to confirm the diagnosis. These tests
are possible in most elderly people excepting cases of severe dementia.
MECHANISMS: Pathophysiology of asthma in the elderly may be characterized by
superimposition of different factors: 1) the effect of age which is associated
with airway adrenoreceptor dysfunction; 2) the impact of chronic pulmonary
diseases which may increase airways inflammation; 3) the role of triggers such as
infections or various medications. MANAGEMENT: Management of asthma consists in a
specific treatment of trigger(s) associated with anti-inflammatory and
bronchodilator medications. Elderly subjects may have difficulty using
offinhalators and spacer devices are widely used.
PMID- 9767880
TI - [Surgical treatment of pulmonary metastasis of colorectal cancer. Prognostic
survival factors].
AB - SURVIVAL RATES: Less than 5% of patients with pulmonary metastasis from
colorectal carcinoma will survive at 5 years, but 30% will survive at 5 years
after surgical treatment. MAIN PROGNOSTIC FACTORS: The number of nodules,
presence of regional lymph node metastases, disease-free interval between
treatment of the primary tumor and development of metastasis as well as serum CEA
level are the main prognostic discriminants. INDICATIONS FOR SURGERY: An
aggressive operative approach is indicated even when there are pulmonary and
extra-pulmonary localizations. Repeat thoracotomy is warranted for recurrent
disease.
PMID- 9767882
TI - [Acute myocardial infarction. Experiences of the referral network of the Beaujon
and Bichat hospitals (with the collaboration of the Emergency Medical and
Resuscitation Service of Beaujon)].
AB - OBJECTIVES: Hospital management of acute myocardial infarction raises many
problems in terms of medical care and organization, especially concerning the use
or not of emergency corongraphy and angiography. We assessed the pertinence and
consequences of a referral network operating between two cardiology units at the
Beaujon and Bichat hospitals in Paris. All interventional procedures were
performed at the Bichat unit. Prehospital emergency care units were integrated
into the exprience and informed of indications for first line coronarography.
METHODS: All cases of myocardial infarction admitted within 6 hours to the two
units between 1993 to 1996 were analyzed and compared. RESULTS: Indications for
referral from Beaujon to Bichat for emergency coronarography and possible
angioplasy declined from 21% in 1993 to 10% in 1996. This decline was
particularly noteworthy for first intention indications suggesting improved
prehospital selection since the number of cases of acute myocardial infarction
admitted to Beaujon remained unchanged. Certain patient characteristics differed
between the two units: age (68.4 +/- 12.9 years at Beaujon versus 60.5 +/- 13.6
years at Bichat in 1996, p < 0.01) and reperfusion attempts (73% versus 90% in
1996 respectively, p < 0.01). The rate of fatal and non-fatal events were not
different: 40 and 40% at Beaujon and 38 and 28% at Bichat in 1993 and 1996
respectively. CONCLUSION: These findings demonstrate that a management network
can operate effectively between two hospital cardiology units and emergency care
structures, allowing better patient selection for emergency coronography and
possible angioplasty.
PMID- 9767883
TI - [Osteoarticular Mycobacterium xenopi infection].
AB - BACKGROUND: Mycobacterium xenopi is a potential pathogen for man and can cause
bone and joint infections, particularly spondylodiscitis. Most cases of infection
occur in fragilized patients and are found more and more often in AIDS patients.
CASE REPORT: A 41-year-old HIV+ woman developed cervical spondylodiscitis due to
Mycobacterium xenopi infection. The strain was isolated from a discovertebral
biopsy and was resistant to several antibiotics. Outcome was unfavorable.
DISCUSSION: Most of the cases reported to date have involved spondylodiscitis of
the thoracic or lumbar spine. To our knowledge, this is the first report of
cervical spondylodiscitis dut to Mycobacterium xenopi in an HIV+ patient.
Antibiotic combinations using fluoroquinolones and new macrolides are usually
prescribed. Such protocols may provide cure of these opportunistic infections in
immunodeficient patients.
PMID- 9767885
TI - [Pregnancy in a patient treated with trientine dihydrochloride for Wilson's
disease].
PMID- 9767884
TI - [Enterobacter aerogenes pneumopathy treated by a cefepime-sulbactam-gentamicin
combination].
AB - BACKGROUND: Enterobacter aerogenes is the fifth most frequent pathogen causing
nosocomial infections. Several strains have developed multiple resistance by over
production of a natural cephalosporinase and by the presence of wide-spectrum
betalactamases. CASE REPORT: A patient with chronic respiratory failure developed
Enterobacter aerogenes pneumonia while under mechanical ventilation. The
infection was successfully treated with a cefepime, sulbactam, gentamycin
combination. DISCUSSION: Choosing the optimum antibiotic therapy is a difficult
task in many nosocomial infections. In certain cases, combining a betalactamase
inhibitor with the appropriate antibiotic can improve bactericidal activity and
provide successful cure.
PMID- 9767886
TI - [HIV arthritis: an entity apart from HIV infection].
PMID- 9767887
TI - [A large testis disclosing a tumor of the colon].
PMID- 9767888
TI - [Computerized prescriptions in the hospital geriatric service. Improvement of the
precision quality of medical computers].
PMID- 9767889
TI - [Parietal suspension during laparoscopic cholecystectomy in patients with
respiratory insufficiency].
PMID- 9767890
TI - [Pulmonary embolism. A development which concerns us all].
PMID- 9767891
TI - [Pulmonary embolism. Risk factors of venous thromboembolic disease].
AB - RISK FACTORS: Management of deep venous thromboembolism both in terms of
diagnosis and therapeutic and prophylactic strategies has been greatly improved
by advances in knowledge of the main acquired and intrinsic risk factors.
RESISTANCE TO ACTIVATED PROTEIN C: This is by far the most frequent coagulation
disorder predisposing to venous thromboembolism. Other intrinsic factors favoring
thrombus formation (anti-thrombin II, protein C or protein S deficiencies) are
much more uncommon. Laboratory tests in search for these anomalies are indicated
essentially for patients who develop repeated episodes of venous thrombus
formation. PROPHYLAXIS: Excepting specific cases, anticoagulant prophylaxis is
not indicated in any of these anomalies beyond the usual treatment of a first
episode. Among the risk factors for acquired deep vein thromboembolism, only
surgery and certain obstetrical indications have been investigated sufficiently
to define validated prophylaxis strategies. For medical risks, the benefit of
anticoagulant prophylaxis has been demonstrated in certain disease states such as
cancer, antiphospholipid syndrome and the acute phase of myocardial infarction
although no widely accepted strategy has yet been established.
PMID- 9767892
TI - [Pulmonary embolism. The role of computed tomography angiography].
AB - NONINVASIVE PROCEDURE: Helical CT angiography is a noninvasive procedure whose
only relative contraindications are renal insufficiency and iodine allergy.
MASSIVE PULMONARY EMBOLISM: If a massive pulmonary embolism is suspected, helical
CT angiography is the examination of choice because of its high accuracy in
detecting proximal thrombi and its safety profile. NON-MASSIVE PULMONARY
EMBOLISM: If a non massive pulmonary embolism is suspected, helical CT
angiography, because of its high specificity, can be the first examination
instead of scintigraphy. If a thrombus is depicted by CT, the diagnosis of
pulmonary embolism is confirmed and treatment is started. If no thrombus is
visualized by CT, pulmonary embolism can be ruled out in most cases. In case of
doubt, another noninvasive procedure should be performed. Angiography should be
the exception and seldom is needed.
PMID- 9767893
TI - [Pulmonary embolism. Current aspects of treatment].
AB - INDICATIONS FOR DRUG THROMBOLYSIS: There has been much debate on the indications
for drug thrombolysis in pulmonary embolism. Thrombolysis would not appear to be
justified excepting in massive pulmonary embolism when clinical signs or
explorations evidence poor hemodynamic tolerance. Current data would confirm its
independent effect on reducing mortality in such cases. MECHANICAL THROMBOLYSIS:
The clinical efficacy of mechanical thrombolysis has not been demonstrated. It
should not be used outside rigorously controlled clinical trials in patients with
severe pulmonary embolism and with a formal contraindication for drug
thrombolysis or in case of failure. THE PREPIC STUDY: The first controlled
prospective trial on caval filters confirmed that indications for caval
interruption in patients with proximal deep vein thrombosis should be limited to
contraindications and failures of anticoagulant therapy. Other indications for
filters, whether temporary or definitive, should be evaluated with specific
controlled prospective trials. LOW-MOLECULAR WEIGHT HEPARINS: If this possibility
is confirmed for the treatment of pulmonary embolism, it will provide a simple
rational treatment for venous thromboembolism. 'SMALL CLOTS': Changing diagnostic
strategies, particularly the use of helical CT angiography, has raised the
question of therapeutic abstention when "small" clots are undetectable by this
exploration.
PMID- 9767894
TI - [An intragastric bridge: endoscopic extraction].
PMID- 9767895
TI - [Ischemic colitis during colonoscopy: progression toward stenosis].
PMID- 9767896
TI - [Dialysis in octagenarians: search for mortality risk factors. Consecutive series
of 30 patients].
AB - OBJECTIVE: To assess renal replacement therapy in elderly subjects aged 80 years
or more in order to depict factors predicting mortality. PATIENTS AND METHODS: We
retrospectively studied 30 consecutive patients at the time of starting dialysis
from January 1995 to August 1995 and followed this population though March 1996.
RESULTS: Only past ischemic heart disease and emergency situations were
emphasized as predictor factors of mortality risk. No difference according to
mortality between hemodialysis and peritoneal dialysis subgroups was found.
CONCLUSION: Excepting usual contraindications for uremic populations, no
objective medical criteria are at present time sufficient for excluding chronic
renal replacement therapy in very old patients. However, its effect on quality of
life must be estimated in order to determine the cost/benefit ratio.
PMID- 9767897
TI - [Papillary fibroelastoma of the heart (giant Lambl excrescence). Clinical
anatomical study on 10 surgically treated patients].
AB - OBJECTIVES: The growing number of reports of surgery for papillary fibroelastomas
of the heart led us to evaluate the diagnostic potential of ultrasonography in
patients with cerebral or coronary signs and to assess the efficacy of
anticoagulant therapy in preventing recurrent cerebral ischemia and disease
progression after resection. PATIENTS AND METHODS: Ten cases of echographically
diagnosed fibroelastoma of the heart treated by surgery were analyzed together
with cases reported in the literature. RESULTS: Transesophageal echography has
been shown to be the superior method. Surgical resection has given good results
and the postoperative course is always excellent. Recurrent embolism occurred in
two of our cases despite well-conducted anticoagulation. DISCUSSION: Surgical
resection should be performed as early as possible because anticoagulation does
not appear to sufficiently protect against embolic events, particularly cerebral
events.
PMID- 9767898
TI - [Peritoneal benign polycystic mesothelioma].
AB - BACKGROUND: Benign multicystic peritoneal mesothelioma (BMPM) is an uncommon
condition. CASE REPORT: We observed a typical case of BMPM occurring in a 57-year
old man who presented with a painful mass of the lower right quadrant. The
pathology using immunostaining gave the diagnosis. DISCUSSION: The diagnosis of
BMPM can be suspected on the basis of imaging findings, but is usually confirmed
by pathology. The only treatment for BMPM is surgical resection. Prognosis is
good despite frequent recurrences. Two main hypotheses based on etiopathology can
be discussed: does BMPM consist of a mesothelioma proliferative and reactional
lesion or is it a real mesothelioma tumor?
PMID- 9767899
TI - [Emphysematous cystitis: report of a case].
PMID- 9767900
TI - [Late-onset pleurisy: a rare complication of thoracic radiotherapy].
PMID- 9767901
TI - [Current problems of lead poisoning].
AB - In collaboration with private associations and public services, we screened a
targeted population for serum lead levels and observed lead poisoning (serum Pb >
100 micrograms/l) in 6 out 44 children living in precarious conditions in
Poitiers, France. This observation underscores some of the major problems
encountered in the battle against lead poisoning in western countries. First, the
social, economical or legal situation of the population at risk often results in
exclusion from the normal health care network. If after a coordinated effort
based on mutual trust, children exposed to lead poisoning can be identified, the
second problem is to identify the source of intoxication. Scaling paint in the
current housing may be incriminated, but how can the true source be identified
when the populations concerned change residence often and may be unwilling to
disclose their previous residence due to fear of reprisals for themselves or the
new occupants? And if the source is identified, the cost of rehabilitation or the
illegal situation of the family may raise further problems requiring adapted
solutions. The prevention of lead poisoning calls for a targeted screening
program, combined efforts of public authorities and health care workers, and
close cooperation with private associations. All intoxicated children should be
removed from the source of exposure and their families protected from the risk of
sanctions. Only an active and practical public health policy can provide the
solution to this continuing public health problem.
PMID- 9767902
TI - [Digitalized conventional radiology and image network].
PMID- 9767903
TI - [What can be expected from gene therapy in respiratory diseases?].
PMID- 9767904
TI - [Urologic surgery and allergy to natural latex].
PMID- 9767905
TI - [Risk factors in venous thromboembolism].
PMID- 9767907
TI - [Evaluation of prescription of antibiotics in an intensive care unit].
AB - OBJECTIVES: In order to optimize prescriptions, we conducted a qualitative
evaluation of antibiotic prescription in an intensive care unit. METHODS: A
prospective observational study was performed on 100 consecutive prescriptions
from 11/95 to 4/96. RESULTS: Among 14 documented cases, initial antibiotic
therapy was in accordance with antimicrobial susceptibility patterns in all but
one case. Among 86 empirical cases, 38 were secondarily documented, yielding 43
microorganisms. Of these 38, 27 were susceptible to 2 or more empirical
antibiotics, 3 to only 1 and 8 to none. Antibiotics were modified in 23/38 (60%)
cases, resulting in drug changes (n = 21) or drug addition (n = 2). In all cases,
the new prescription was consistent with the antibiogram. In the 48 cases where
no microorganism was isolated, antibiotic change was guided by clinical course
and occurred in 6 (12.5%) cases. A switch to older, cheaper or more narrow
spectrum antibiotics was possible in 18 cases, but was actually done in only 4
(22%). Dosage errors were observed in 5 cases of initial therapy. Second line
therapy contained 8(21%) dosage errors. Most frequently, isolated organisms at
admission were: Staphylococcus sp. (n = 15), P. aeruginosa (n = 11) and S.
pneumoniae (n = 10). New pathogens emerged in 16 patients (16%) receiving
antibiotics. The most frequent was P. aeruginosa in 4 patients receiving
ofloxacin + amoxicillin +/- clavulanic acid. CONCLUSION: These results are
encouraging, however, the use of guidelines and periodic evaluation of antibiotic
prescription practices might improve the efficiency of empirical antibiotic
prescriptions and reduce overall antibiotic costs.
PMID- 9767906
TI - [False Osler node].
PMID- 9767909
TI - [Intermediary syndrome in acute malathion poisoning].
AB - BACKGROUND: Acute poisoning by an organophosphorus insecticide is frequently
observed in Morocco. We report a case of malathion poisoning complicated by an
intermediate syndrome. CASE REPORT: A 42-year-old woman was hospitalized 3 hours
after ingestion of 50 g of malathion. Intubation and ventilatory assistance was
required due to failing consciousness and bronchial plugging. On day 4, a
neurological syndrome suggestive of the intermediary syndrome with diaphragmatic
palsy made it necessary to continue ventilatory assistance to day 20. DISCUSSION:
The intermediary syndrome occurs 24 to 96 hours after the acute cholinergic phase
of organophosphorus poisoning. It consists of an exclusive neuromuscular
involvement. The intermediate syndrome is confined to an abnormality of
neuromuscular function in specific muscle groups: proximal limb muscles, neck
flexors, motor cranial nerves and respiratory muscles, with difficult weaning
from respiratory assistance. The intermediary syndrome is quite uncommon. The
risk of respiratory failure emphasizes the need for close monitoring in an
intensive care setting for at least 96 hours, depending on the intensity of the
cholinergic syndrome.
PMID- 9767908
TI - [Long-term stability of bone mineral density in patients with renal transplant
treated with cyclosporine and low doses of corticoids. Protective role of
cyclosporine?].
AB - OBJECTIVES: Cyclosporine has been thought to have a deleterious effect on bone in
transplant recipients because of high turnover osteopenia observed in humans
after transplantation. However, varying confounding factors such as renal and
parathyroid function, cumulative steroid doses and previous exposure to
aluminium, also play a role and hinder interpretation of the cyclosporine effect
on bone mineral density (BMD). PATIENTS AND METHODS: A 2-year prospective study
was conducted to measure BMD starting 3 months after transplantation and bone
remodeling markers from the first post-transplantation day in 52 kidney
recipients with no prior exposure to aluminum. None of the patients experienced
rejection and at 3 months all had good stable renal function (serum creatinine
137 mumol/l) and mildly elevated parathyroid hormone levels (1.5 times the upper
limit of normal). All patients were given the same low dose steroid treatment (10
mg/day) and at 6 months cyclosporine was decreased from 7 to 4.8 mg/kg/day.
RESULTS: BMD measured by double energy X-ray absorptiometry, (DEXA) and expressed
in Z score, was moderately decreased at 3 months for the vertebrae (-1.40), the
femoral neck (-1.34) and the ultradistal radius (-0.95) which have predominantly
cancellous bone and was significantly less decreased (p < 0.05) for the lower
third of the radius (-0.6) which is mainly cortical bone. BMD measurements were
comparable at 6, 12 and 24 months. When measured by axial computerized tomography
(ACT) BMD of the vertebrae showed a non-significant increase of Z score from
1.37 to -1.19 at 2 years. Bone remodeling markers was observed up to month 6
(from month 3 for osteocalcine and from month 1 for total and bone alkaline
phosphatase and urinary pyridinoline), then returned to baseline levels at 2
years in parallel with decreased cyclosporine dosage. The increase of vertebral
BMD measured by ACT at 1 year was correlated both to cyclosporine dose at 1 year
and to bone alkaline phosphatase at 6 months. CONCLUSION: Our data confirm the
presence of moderate osteopenia 3 months after transplantation, predominantly in
trabecular bone, logically linked to the initial high doses of corticosteroids.
The long-term stability of BMD measured by DEXA and the correlation of vertebral
BMD increase measured by ACT with cyclosporine dose and bone alkaline phosphate
suggest that cyclosporine had a beneficial immunosuppressor effect by stimulating
bone remodeling and thus counterbalancing the suppressive effect of
corticosteroids.
PMID- 9767910
TI - [BCG reactivation: a rare but specific sign of Kawasaki disease].
PMID- 9767911
TI - [Cotrimoxazole-induced aseptic meningitis: two cases].
PMID- 9767912
TI - [Acute levamisole poisoning].
PMID- 9767913
TI - [Is combined statin and fibrate therapy indicated in the management of mixed
hyperlipidemia?].
AB - INSUFFICIENT PROGRESS: The treatment of hyperlipidemia leads to a reduced risk of
coronary disease. This has been displayed notably since clinical trials have used
statins. However, despite these treatments, a risk of coronary ischemia remains,
which is not insignificant. There are several causes of this persistent risk
which need to be analyzed. THE QUALITATIVE ASPECT OF LOW DENSITY LIPOPROTEINS:
LDL are heterogeneous. This is displayed by a distribution of sizes varying from
one subject to another. The predominance of small LDL is frequently found in
coronary subjects detected during prospective or retrospective studies. The
atherogenicity of small LDL can be explained by their physico-chemical
characteristics. A remarkable fact is the predominance of small LDL in subjects
with a mixed hyperlipidemia presenting a high risk of atherosclerosis. THE
EFFECTS OF HYPOLIPIDEMIANTS: Statins greatly decrease LDL-cholesterol without
changing LDL distribution according to size. Conversely, fibrates noticeably
modify LDL distribution, reducing the percentage of small LDL. A PROPOSAL FOR THE
TREATMENT OF SUBJECTS SUFFERING FROM MIXED HYPERLIPIDEMIA: If the concentration
of LDL (reflected by LDL-cholesterol) and LDL distribution are two risk factors
of atherosclerosis, hypolipidemic treatment should aim to act upon these two
parameters, but no commercialized hypolipidemiant is effective enough as fas as
they are both concerned. Therefore the combination of two hypolipidemiants, a
statin and a fibrate, each having a predominant effect on one of the two factors,
could be particularly effective in reducing coronary risk. This therapeutic
association is effective on classic lipid parameters, does not entail more side
effects than a monotherapy, and is not precluded by the RMO when there is a high
vascular risk, which is often the case in mixed hyperlipidemia.
PMID- 9767914
TI - [Alzheimer disease. Epidemiology, genetics and physiopathological hypotheses].
AB - RISK FACTORS: Aging is the chief risk factor for Alzheimer's disease (AD). Other
risk factors are aluminum in drinking water, diabetes mellitus, head trauma.
Protective factors are: higher education, cigarette smoking, nonsteroidal anti
inflammatory drugs and estrogen use. GENETIC FACTORS: Mutations of presenilins 1
and 2 and of the APP gene in families with early-onset AD. Apolipoprotein E
polymorphism in late-onset familial and sporadic AD. PATHOGENIC HYPOTHESES:
Amyloid deposits in senile plaques and therefore dementia could be due to an
overproduction of Abeta (Down's syndrome) or due to the primary (APP mutation) or
secondary (role of diabetes, mellitus, apoE polymorphism: protective effect of
estrogen) abnormal neurotoxic feature of Abeta. The hyperphosphorylation of tau
(a protein which plays a pivotal role in the axonal transport), perhaps regulated
by the apoE polymorphism could lead to neurofibrillar degeneration. Neurotoxic
mediators produced by the activated microglia (perhaps activated by neuronal
damage) and oxidative stress could also be involved in the neurodegeneration.
PMID- 9767916
TI - [Images in medicine. Dissecting esophagitis: a rare but typical endoscopic
aspect].
PMID- 9767915
TI - [Alzheimer disease, markers in the cerebrospinal fluid. Support of
physiopathologic hypotheses].
AB - CERTAIN DIAGNOSIS: Because the certainty diagnosis of Alzheimer's disease is
defined after autopsy or brain biopsy by the presence of neurofibrillar
degeneration (NFD), extracellular senile plaques and vascular deposits of amyloid
in the hippocampus amygdalus and the cerebral cortex, some authors have searched
for biological ante-mortem markers of AD, particularly in the cerebrospinal fluid
(CSF) which is essentially derived from brain tissue. SEARCH FOR MARKERS: Studies
have investigated the CSF level of neurotransmitters, neuropeptides, amino acids,
trace elements, constituents of NFD and senile plaques in a diagnostic and
pathogenic perspective. HOPE FOR DIAGNOSIS: Even though ethical, technical and
methodological difficulties met by authors are important and even though many
clinical and biological parameters must be taken into account, these studies
bring important pathogenic evidence and allow hope that markers of AD which are
so necessary for early diagnosis and objective study of therapies will be found.
PMID- 9767917
TI - [Images in medicine. Alveolar microlithiasis].
PMID- 9767918
TI - [Treatment of hemophilia B with 15 nm filtered factor IX-LFB].
PMID- 9767919
TI - [Pneumococcal infections in the adult population observed at the Poitiers
University Hospital. Epidemiologic and clinical study].
AB - OBJECTIVES: The aim of this study was to assess the prevalence of penicillin
nonsusceptible pneumococcus (PNSP) infections and their clinical and
microbiological features among an adult population hospitalized at the Poitiers
University Hospital. PATIENTS AND METHODS: A prospective study was conducted
between November 1994 and October 1995 and included all pneumococcus infections.
RESULTS: Fifty-three adults with one pneumococcal strain were included. The
overall rate of PNSP strains was 28%. Infections with PNSP strains were more
resistant than penicillin-susceptible pneumococcus to other antibiotics. The most
frequent infection was pneumonia (36 infections, 28% PNSP). DISCUSSION: The rate
of PNSP in pneumococcal infections was the same in the Poitiers University
Hospital as in national surveys in France. The high percentage of multiresistant
strains (86.5%) limit the use of antibiotics other than beta-lactams. Surveys of
pneumococcal resistance to antibiotics are needed to adapt antibiotic strategies
to the local epidemiological situation.
PMID- 9767920
TI - [Hypercalcemia associated with hyperleukocytosis, a new paraneoplastic syndrome].
AB - BACKGROUND: The association of hypercalcemia and leukocytosis constitutes a novel
paraneoplastic syndrome rarely reported in the course of head and neck and lung
squamous cell carcinoma. We report 7 new cases. CASE REPORTS: In 5 cases the
diagnosis was well-differentiated squamous cell carcinoma, in 1 differentiated
non-small-cell carcinoma and in 1 adenocarcinoma of unknown origin. There was no
argument favoring hyperparathyroidism in any of the cases. Microbiology tests
were negative and large spectrum antibiotics were unsuccessful, eliminating an
associated infection as cause of the leukocytosis. DISCUSSION: This association
probably involves the secretion of hematopoietic growth factors such as G-CSF or
GM-CSF by the tumor, acting simultaneously on osteoclasts and granulomonocytic
cells which have common precursers.
PMID- 9767921
TI - [Hereditary xanthinuria, rare cause of hypo-uric acidemia. 2 cases].
AB - BACKGROUND: Hypouricemia can be observed in uncommon situations as in our two
patients with hereditary xanthinuria. CASE REPORTS: In the first case, hereditary
xanthinuria was discovered in a 36-year-old man when routine tests revealed
hypouricemia. In the second case, a 76-year-old woman, hypouricemia was also a
fortuitous discovery. She had major xanthinuria and a radiotranslucid lithiasis
in the right kidney. DISCUSSION: Hereditary xanthinuria is characterized by
hypouricemia, low urinary urate excretion and increased concentration of xanthine
and to a lesser extent hypoxanthine. The disease results from a defect in
xanthine oxidase and is considered to be transmitted by autosomal recessive
heredity. This rare metabolic disorder is more often asymptomatic and detected by
routine chemistry. Development of xanthine lithiasis is directly related to the
low solubility of xanthine and is the main complication of the disease, occurring
in 30-40% of patients. There is no effective treatment and the only useful
measure is to prevent xanthine urolithiasis by maintaining urinary output above 2
l/day.
PMID- 9767922
TI - [Extracorporeal circulation for warming in severe accidental hypothermia. 3
cases].
AB - BACKGROUND: Severe accidental hypothermia with central temperature below 28
degrees C can result from prolonged cold exposure and lead to a fatal outcome by
spontaneous or provoked ventricular fibrillation. CASE REPORT: Three patients
were referred for central temperature below 24 degrees C. At admission, the
patients had major ventricular rythm disorders (two were in a state of
circulatory arrest and the third had auricular fibrillation and circulatory
collapse). Emergency care associated internal warning using extracorporeal
circulation via the femoro-femoral route with a centrifuge pump. Outcome was
favorable in 2 cases. DISCUSSION: Prognosis is very poor in patients who
experience severe accidental hypothermia (< 28 degrees C) with circulatory
collapse. Death often results from major rhythm disorders. Optimal emergency
rewarming and oxygenation using extracorporeal circulatory assistance can be
successful.
PMID- 9767924
TI - [Pseudo-sarcoidotic lymphoma and nephrotic syndrome in a hepatitis C-carrying
female patient].
PMID- 9767923
TI - [Lengthened activated thromboplastin time in the course of tinzaparin therapy of
accidental venous thromboembolism. Pilot study].
PMID- 9767925
TI - [Nosocomial infections as indicators of quality of health care in intensive care
units].
PMID- 9767926
TI - [Apropos of the localization of gastric epidermoid carcinoma].
PMID- 9767927
TI - [Drug induced lithiases].
PMID- 9767928
TI - [Hepatitis C following kidney transplantation].
PMID- 9767929
TI - [Medical images. Pseudo-obstruction of the small intestine].
PMID- 9767930
TI - [Medical images. Diverticulum in the mid-third of the esophagus caused by "drug
inclusion"].
PMID- 9767931
TI - [Pharmocokinetics of ciprofloxacine].
PMID- 9767932
TI - [Losing consciousness: role of the venous lactate levels in the diagnosis of
convulsive crises].
AB - OBJECTIVES: This prospective study was conducted to evaluate the usefulness of
venous lactate assay in the diagnosis of generalized seizures. PATIENTS AND
METHODS: Over a three month period, 78 consecutive adults admitted to the
emergency unit for unconsciousness were included in the study. Three study groups
were defined: patients with generalized seizures (n = 22), unconscious patients
without seizure (n = 34) and known epileptic patients with unexplained malaises
(n = 22). Patients with a disease susceptible of increasing lactate levels were
excluded. Peripheral venous blood was drawn to determine lactates, bicarbonates
and pH on a blood gas analyzer. All determinations were performed within 5
minutes of blood withdrawal. CPK level was also determined with an enzymatic
method. RESULTS: In patients who had seizures, venous lactate levels were higher
than those in patients who had no seizures: 4.3 +/- 0.5 mmol/l in generalized
seizure patients versus 1.64 +/- 0.1 and 2.2 +/- 1.39 in unconscious patients
without seizure and known epileptic patients with unexplained malaise
respectively. The threshold lactate level of 2.5 mmol/l given by ROC curves gave
a 0.97 specificity and a 0.73 sensitivity. DISCUSSION: The acidosis observed in
patients with generalized seizures results from the combined effects of
respiratory and metabolic acidosis. High lactate level would be a consequence of
hypoxemia, per seizure rise in catecholamines, and aerobic and anaerobic
metabolism in muscles during the tonic-clonic phase. In patients presenting in an
unconscious state, increased lactate levels, even when determined up to 2 hours
after venous blood withdrawal, could be a useful parameter for the diagnosis of
epileptic seizure.
PMID- 9767933
TI - [Rapid progress of cirrhosis in hepatitis C: the role of age at the time of viral
contamination].
AB - OBJECTIVE: The aim of this study was to assess predictive factors for the
progression to liver cirrhosis in hepatitis C. METHODS: One hundred thirty six
patients (79 men; 57 women; mean age 39 years) with transfusion or intravenous
drug use-associated hepatitis C virus (HCV) infection were studied. Sex, cause of
infection, duration of contamination, and genotype were studied as predictive
factors of progression to liver cirrhosis. RESULTS: One hundred twenty three
patients presented with chronic hepatitis without cirrhosis and 13 had cirrhosis.
At the time of liver biopsy, rates of cirrhosis were: 0% before 40 years, 10%
between 40 and 60 years, and 47% after 60 years. (p < 0.05). Rates of cirrhosis
according to the age at the time of contamination were as follows: 3% before 30
years; 16% between 30 and 50 years; 46% after 50 years even though duration of
the disease was comparable in the three groups. In multivariate analysis, two
independent factors were associated with liver cirrhosis: age at contamination
and duration of infection. CONCLUSION: Duration of infection and especially age
at contamination seem better correlated with the probability of cirrhosis than
the route of transmission or the genotype 1b. The results of this study suggest
that progression to cirrhosis is slower in cases of contamination before 30 years
of age than later on. Age at the time of contamination is an important predictive
factor of progression to cirrhosis.
PMID- 9767934
TI - [Acute arterial hypertension caused by dissecting aneurysm of the renal artery].
AB - BACKGROUND: Aneurysm of the renal artery is an uncommon discovery at
arteriography performed as part of a hypertension work-up. CASE REPORTS: We
observed acute hypertension following dissection of a renal artery aneurysm which
led to circulating channel stenosis. After surgical correction of the lesion,
arterial pressures returned to normal. DISCUSSION: Most cases of renal artery
aneurysm do not cause hypertension. In such cases, the high blood pressure is
idiopathic or related to fibrodysplastic stenosis of the renal artery often
associated with aneurysm formation. In rare cases with obstructive complications
alone an aneurysm may lead to acute hypertension either after dissection as in
our case or after thrombus formation. Surgery is generally required.
PMID- 9767935
TI - [Cogan syndrome in a mature adult].
PMID- 9767936
TI - [Aseptic osteonecrosis of the femur head in the course of rheumatoid purpura].
PMID- 9767937
TI - [Antibodies against cytomegalovirus and risk of hepatitis C].
PMID- 9767938
TI - [Should occupational medicine physicians be linked to future computerized medical
record networks?].
AB - Upcoming reforms of the health care system place high expectations on
computerized medical file networks to control medical expenditures. In France,
information flow from the care delivery sector to the occupational medicine
sector is often slow or incomplete. Company and social security expenditures or
dysfunctions as well as patient incomfort may result. An analysis of occupational
medicine practices and the needs of physicians working in this sector leads to
several perspective proposals for improvement including access to future
computerized medical file networks and the health data card Sesame.
PMID- 9767940
TI - [Prevention of diabetic nephropathies].
PMID- 9767939
TI - [5th Conference on Opportunistic Retrovirus Infections in HIV: contribution of
anti-retroviral combinations].
PMID- 9767941
TI - [Type 2 endocrine neoplasms. Introduction].
PMID- 9767942
TI - [Type 2 endocrine neoplasms. Clinical aspects].
PMID- 9767943
TI - [Type 2 endocrine neoplasms. Genetic aspects and diagnosis].
PMID- 9767944
TI - [Type 2 endocrine neoplasms. Prognosis and therapeutic problems].
PMID- 9767945
TI - [Images in medicine. Rectal cancer: endoscopic-ultrasonic evaluation of the loco
regional extension of the disease].
PMID- 9767946
TI - [The role of ciprofloxacin in the management of chronic sinusitis].
PMID- 9767947
TI - [Acute poisoning during substitution therapy based on high-dosage buprenorphine.
29 clinical cases--20 fatal cases].
AB - OBJECTIVES: Buprenorphine has been an important advance in care for drug abusers,
but the toxic risk may be fatal. We report here two original series of
buprenorphine poisoning in opiate abusers on substitution therapy. PATIENTS: The
first series included 20 males and 9 females, aged 20-35 years (mean = 27.5) with
non-fatal poisoning. The second series included 20 subjects (19 males, 1 female)
aged 14-48 years (mean = 26.6) with a fatal outcome. All subjects were opiate
addicts taking high-dosage sublingual buprenorphine formulation as substitution
therapy. RESULTS: Blood concentrations of buprenorphine were found in all cases
to remain at a low level (1.0-2.3 ng/ml, m = 1.4 ng/ml, and 1.1-29.0 ng/ml, m =
8.4 ng/ml in non-fatal and fatal cases respectively). Almost all cases involved
concomitant intake of psychotropic medications, especially benzodiazepines (18
non-fatal and 17 fatal cases). DISCUSSION: These observations confirm previously
reported data on the danger of buprenorphine-benzodiazepine combinations.
Intravenous injection of crushed tablets also appears to be a risk factor (8
deaths and 10 non-fatal poisonings). This series highlights the need for
improvement in the recently developed French program for substitution therapy
with high-dosage buprenorphine in heroin addicts.
PMID- 9767948
TI - [Agammaglobulinemia with the absence of circulating B-lymphocytes. 9 cases].
AB - OBJECTIVES: Agammaglobulinemia with absence of circulating B lymphocytes is a
rare genetically transmitted immunodeficiency that appears in early childhood and
affect mainly boys. The clinical manifestations of the disease are rather
heterogeneous. PATIENTS AND METHODS: Nine patients (7 boys and 2 girls) were
diagnosed as suffering from agammaglobulinemia with absence of circulating B
lymphocytes, over a period of 6 years. Quantitation of immunoglobulins and search
for circulating B lymphocytes were respectively performed by the Mancini method
and immunofluorescence using T specific (anti-CD3, anti-CD4 and anti-CD8) and B
(anti-CD19) monoclonal antibody. RESULTS: The disease started to manifest
clinically at the mean age of 8.7 months (4-16 months). The mean age at diagnosis
is 4 years (1-11 years). The clinical manifestations were essentially recurrent
infections of the lung and the gastrointestinal tract. However, bacterial
meningitidis was observed in 3 patients. Severe complications such as an
echovirus 27 meningoencephalitis and a chronic active hepatitis (1 patient) and a
pericarditis (1 patient) were observed. All of our patients lacked circulating B
lymphocytes and had low or null immunoglobulin levels. Five patients were treated
by intravenous immunoglobulin (Ig) and 3 were treated by intramuscular
immunoglobulin with a residual IgG level respectively of 5.5 g/l and 3.3 g/l.
CONCLUSION: Recurrent infections are the principal manifestation of the
agammaglobulinemia, early Ig treatment is the only therapy allowing improved.
PMID- 9767949
TI - [Tamponade in patients with systolic left ventricular dysfunction. An atypical
presentation].
AB - BACKGROUND: Left ventricular failure has been described following surgery due to
localized compression of the left ventricle and in case of diastolic left
ventricular dysfunction after pericardiotomy or pericardiocentesis. CASE REPORTS:
Global heart failure was observed in 3 patients with dilated cardiopathy who
developed tamponade. Systolic left ventricular dysfunction was caused by ischemic
heart disease in one patient and secondary to anthracyclin chemotherapy in the
two others. The effusion was successfully removed with pericardiocentesis in all
three cases. No specific complications were observed. DISCUSSION: Although
exceptional, tamponade may occur in patients with signs of left ventricular
failure.
PMID- 9767951
TI - [Acute ulceration of the vulva during a primary Epstein-Barr virus infection].
PMID- 9767950
TI - [Hypovitaminosis K during treatment with doxycycline].
PMID- 9767953
TI - [Prohibition of human cloning. The status 1 year after the Scottish experience].
PMID- 9767952
TI - [Cushing syndrome: a secondary cause of osteoporosis not to be ignored].
PMID- 9767954
TI - [The National Academy of Medicine. Hospital nursing courses during the 1st four
years of medical studies].
PMID- 9767955
TI - [Gene therapy in rheumatoid polyarthritis: perspectives].
AB - THE CONCEPT OF GENE THERAPY: Gene therapy is applicable in diseases involving
several genes such as rheumatoid arthritis. Gene transfer is the insertion in
vivo of genetic material necessary to produce a molecule with therapeutic action.
This strategy is currently in experimental stages; feasibility studies in humans
are in the preliminary stage. SEVERAL TARGETS: In experimental models of
rheumatoid arthritis, the most widely studied target genes are those which code
for inflammation inhibitors such as IL-1 receptor antagonists or anti
inflammatory cytokines (IL-4, IL-10, IL-13). Another interesting target would
concern genes coding for molecules inhibiting joint destruction (for example
metalloprotease inhibitors). VECTORS: The development of high-performance vectors
(both viral and nonviral vectors) will greatly improve the expected benefit/risk
potential of gene therapy in general. IN RHEUMATOID ARTHRITIS: The particular
problem in rheumatoid arthritis is the choice of the transfection site. An
articular site would require multiple injections in the different affected
joints. A systemic approach would take into account the general disseminated
nature of the disease.
PMID- 9767956
TI - [Pneumococci with diminished sensitivity to penicillin in pneumopathies. Clinical
consequences].
AB - INCREASING PREVALENCE: Since 1988, French clinicians have been faced with an
increasing prevalence of penicillin-resistant pneumococcal pneumonia. In 1996,
the percentage of strains with reduced susceptibility to penicillin reached more
than 40% and the number of multiresistant strains has increased steadily.
CLINICAL IMPACT: Despite this apparently alarming situation, the clinical impact
is not obvious. Different clinical studies have demonstrated that mortality due
to pneumococcal pneumonia has not been affected by the development of resistant
strains, eventually because the strains involved belong to less invasive
serotypes than penicillin susceptible pneumococci. HYPOTHESIS: The preferential
distribution of penicillin resistance among less invasive serotypes might explain
the development of resistance in carriage strains more often exposed to
antibiotic selection and the greater risk for immunodepressed subjects to acquire
these strains. PRACTICAL CONSEQUENCES: To date, first-line antibiotic therapy
with amoxicillin at the dose of 3g/24 h remains valid for the great majority of
cases. Use of much higher dosages or other antibiotics for pneumococcal pneumonia
would only be rational when penicillin minimum inhibitory concentrations are
above 2 mg/l.
PMID- 9767957
TI - [Pouchitis after ileo-anal anastomosis with a reservoir in hemorrhagic
rectocolitis].
AB - DEFINITION AND FREQUENCY: An ileoanal anastomosis with creation of an ideal pouch
is proposed as the treatment for familial adenomatous polyposis and ulcerative
hemorrhagic rectocolitis. The ideal pouch may become inflammatory in 10 to 30% of
the cases. The diagnosis of pouchitis is based on a clinical, endoscopid and
histological criteria. PATHOGENIC HYPOTHESES: Pouchitis is a late complication,
mainly after ileoanal anastomosis for ulcerative rectocolitis. The pathogenic
mechanism is a subject of debate. Fecal stasis, bacterial pollution, mucine
secretion and the underlying inflammatory disease could be involved. TREATMENT:
Antibiotics active against anaerobic bacteria, such as metronidazole, are
generally given. In case of failure, common antiinflammatory agents used in
inflammatory bowel disease are indicated.
PMID- 9767958
TI - [Millimetric choledochal calculi, diagnosis using echo-endoscopy].
PMID- 9767959
TI - [The role of ciprofloxacin in the treatment of chronic bronchitis].
PMID- 9767960
TI - [Demonstration of the sentinel lymph node in axillary dissection for breast
cancer].
AB - OBJECTIVES: The sentinel node is defined as the first-line axillary lymphatic
drainage node in breast cancer. If the sentinel node can be identified, during
axillary dissection for breast cancer, resection could be limited reducing
subsequent morbidity. However, before modifying the standard dissection
procedure, it is important to prove that the sentinel node is representative of
the metastatic status of other axillary nodes. PATIENTS AND METHODS: Between
March and December 1996, 86 patients (mean age 58 years, range 32-82) underwent
amputation (n = 20), tumorectomy with dissection (n = 56) or tumorectomy followed
by secondary dissection (n = 10) for breast cancer. Ten ml of diluted patent blue
was injected either into the peripheral portion of the tumor or the tumorectomy
cavity. Node dissection was performed 10 to 20 minutes after injection. The blue
sentinel node was identified prior to standard dissection. RESULTS: A mean 12
nodes were removed (range 4-21). Seventy-nine sentinel nodes were identified
(91%) and in 7 cases (8%) a sentinel node could not be identified. In 7 other
cases the sentinel node was a false negative, i.e. non malignant despite
metastases in other dissected nodes. In all the other cases, the status of the
sentinel node predicted the status of the other nodes, i.e. a non-metastatic
sentinel node associated with other metastatic nodes. Finally, in 7 cases, the
sentinel node was the only invaded node among the nodes dissected. During the
last 3 months of the study, the sentinel node was identified in 100% of the cases
and was representative of the overall dissection. CONCLUSION: Identifying the
sentinel node is an alternative to standard axillary node dissection procedures.
The method requires a training period and identification can be improved with
radioimmunologic guidance. Patient selection within the framework of a rigorous
multidisciplinary protocol is indispensable. A nationwide study is currently
being conducted to validate these preliminary results.
PMID- 9767962
TI - [Undifferentiated embryonal sarcoma in the liver of adults].
AB - BACKGROUND: Embryonic sarcoma of the liver is uncommon in adults. We report an
unusual case presenting as a cyst-like formation of the liver. CASE REPORT: The
pre-operative and also the peroperative histology diagnosis was remodelled
biliary cyst. The patient was treated accordingly. The final diagnosis of
embryonic sarcoma of the liver was made when a local recurrence developed. The
patient underwent hepatic resection followed by a chemotherapy and radiotherapy
protocol. Tumor markers were measured within the tumor and gave a positive result
for CA-125. DISCUSSION: Diagnosis of cystic forms of embryonic sarcoma can be a
quite difficult task. Radiological and histological aspects can be helpful. This
report is the first case in which tumor markers were measured within the tumor.
PMID- 9767961
TI - [Is there a correlation between dietary habits and hemorrhoidal disease?].
AB - OBJECTIVES: It is empirically accepted that certain foods play a role in the
pathogenesis of hemorrhoids or their acute exacerbation. The aim of this work was
to determine whether there is a relationship between hemorrhoids and certain food
related or common toxin-related factors. PATIENTS AND METHODS: Two groups of 50
subjects were compared. Group I was composed of 50 patients with hemorrhoid
symptoms. Fifty volunteers with no proctologic abnormality were included in group
II. We used a diet survey to compare total calorie, protein, carbohydrate, fat,
food fiber, water, alcohol, salt, pepper, pimento, tea, and coffee intake was
well as smoking habits. Episodes of constipation were also noted. RESULTS:
Overall calorie intake, as well as protein, carbohydrate and fiber intake were
similar in the two groups as were use of salt, coffee and tea. Dietary intake in
group I was higher for fat (p = 0.02), alcohol (p = 0.01), pepper (p = 0.04, and
pimento (p = 0.001). Subjects in group I drank less water (p = 0.008), smoked
more (p = 0.01) and were more often constipated (p < 0.001) than those in group
II. CONCLUSION: Our findings provide further arguments suggesting that dietary
imbalance or smoking could be involved in the development of hemorrhoids. These
factors should be evaluated in appropriate dietary inquiries. Epidemiological
surveys would be required to confirm their possible causal effect.
PMID- 9767963
TI - [Septic arthritis in AIDS. 10 cases].
PMID- 9767964
TI - [Appendiceal syndrome disclosing Behcet disease].
PMID- 9767966
TI - [Evaluation criteria of multimedia teaching materials in medicine].
PMID- 9767965
TI - [Plasmodium falciparum malaria: type R1 resistance to quinine in west Africa].
PMID- 9767967
TI - [Adenocarcinoma of the pancreas].
PMID- 9767968
TI - [Adenocarcinoma of the pancreas. General characteristics].
AB - EPIDEMIOLOGY: Pancreatic carcinoma ranks fifth among the leading causes of cancer
death in developed countries. Although the incidence of pancreatic cancer is
about 10 per 100,000 inhabitants, the five-year overall survival is barely one to
4%. Few risk factors have been identified. Smoking increases the relative risk by
1.5, chronic pancreatitis by 26. Hereditary formes are rare. PATHOLOGY AND
MOLECULAR ABNORMALITIES: Adenocarcinomas of the ductal phenotype represents about
90% of the pancreatic tumors. Seventy percent of adenocarcinomas are located in
the head. Mutations of K-ras oncogene and p53 anti-oncogene are noted,
respectively, in 80 to 90% and 70% of the ductal adenocarcinomas. The mutation of
p53 is associated with a poor prognosis. Certain less frequent forms such as
mucinous cystadenocarcinomas, or intraductal papillary-mucinous tumors seem to
have a better prognosis. However, this is not true for acinar cell carcinomas
responsible for various paraneoplastic syndromes. PATTERN OF SPREAD: The disease
arises in the ductal epithelium and rapidly spreads to regional lymph nodes and
the liver. At diagnosis, nodal involvement is found in 80% of cases. Half of the
patients have detectable visceral metastasis with a median survival of three to
six months. Among the remaining non metastatic patients, approximately one in 5
has undetected peritonal carcinomatosis. Only 10 to 20% of the patients undergo
surgical complete resection with a median survival of 15 to 19 months.
PMID- 9767969
TI - [Adenocarcinoma of the pancreas. Diagnosis and evaluation].
AB - SYMPTOMS: Pain, jaundice, or weight loss are the presenting features of 90% of
the cases. Patients with tumors of the body or the tail of the pancreas do not
rapidly develop jaundice. Therefore, their diagnosis is delayed and metastasis
are more frequently detected at diagnosis. RADIOLOGIC DIAGNOSIS: The diagnosis
may be established by ultrasonography, endoscopic ultrasonography and most
importantly by CT scan with helicoidal continuous acquisition and contrast
injection. However, these methods do not efficiently detect tumors smaller than 2
cm or with only superficial peritoneal involvement. Laparoscopy and angiography
are used less and less frequently to evaluate resectability. The diagnostic work
up with CT scanning is able to anticipate resectability in 50 to 90% of the
cases. PATHOLOGY: Histopathology must be obtained since 10% of the pancreatic
carcinoma are not of the ductal type and not all pancreatic tumors are malignant.
When a pathological specimen cannot be obtained during surgery, a cytology
specimen may be obtained with a fine needle guided by CT scan. PROGNOSIS:
Survival depends on the possibility of a complete resection of the tumor. If
complete resection is obtained, the prognostic factors are in decreasing
importance: tumor size, lymphatic and vascular involvement, and invasion of peri
pancreatic tissues.
PMID- 9767970
TI - [Adenocarcinoma of the pancreas. Therapeutic strategies].
AB - SURGERY: Surgery whether curative or palliative, is the major modality of
treatment. A complete resection is possible in about 20% of patients with a
median survival of 12 to 16 months and a 20% five year survival. After complete
resection 70 to 80% of patients develop a local recurrence. Biliary and gastro
intestinal bypasses as well as antalgic techniques are useful palliative
procedures. ADJUVANT AND NEOADJUVANT TREATMENT: Chemoradiotherapy is used either
as adjuvant or neoadjuvant treatment. External beam irradiation techniques are
used to deliver 45 to 50 Gy to the pancreas in five to six weeks. Concomitant
fluorouracil is administered in bolus injections or better in continuous
infusion,, either alone or in association with cisplatinum. Chemoradiotherapy
reduces the local relapse rate and slightly, though significantly, increases the
median survival. Therefore, after chemoradiotherapy, metastatic spread becomes
the major cause of death. PALLIATIVE TREATMENT: For locally advanced diseases,
chemoradiotherapy has a true palliative effect with acceptable toxicity.
Metastatic disease remains a challenge. Fluorouracil based chemotherapy with or
without cisplatinum occasionally obtains effective palliation. Among new agents,
only gemcitabine has proven clinical activity associated with low toxicity and is
practical to use. THERAPEUTIC STRATEGY: Presently, patients with resectable
pancreatic carcinoma should be included in a prospective trial to receive
combined modality treatment with adjuvant or neo-adjuvant chemoradiotherapy. The
choice of treatment for patients with locally advanced or metastatic disease,
should be based on the possibility of assuring a satisfactory quality of life.
Present research should progress through controlled clinical trials to study
original systemic treatment and combined modalities able to produce a lasting
local control.
PMID- 9767971
TI - [Bacteriology in community-acquired respiratory pathology].
PMID- 9767974
TI - [Acute hepatitis due to ecstasy].
AB - BACKGROUND: Ecstasy is a synthetic amphetamine which causes a wide variety of
adverse effects. Hepatic toxicity was only recently demonstrated but can be quite
severe. CASE REPORT: A 27-year-old male with no past medical or surgical history
developed jaundice without fever. He was a regular user of ecstasy and had
recently increased the number of doses consumed. No evidence of a viral,
alcoholic, metabolic or autoimmune mechanism was found which could explain the
hepatitis. Complete cure was obtained by discontinuing ecstasy. DISCUSSION: Few
cases of ecstasy hepatic toxicity have been reported. Ecstasy was undoubtedly the
causal agent in this case since other known causes of acute hepatitis were
excluded, confirming the hepatotoxicity of ecstasy reported in the literature.
The liver disease has been reported to range form acute regressive hepatitis to
fatal liver failure. Iterative exposure can lead to fibrosis. The
pathophysiological mechanism of this toxic effect is not well elucidated.
Ischemia alone cannot explain all the clinical forms described, particularly
cases without hyperpyrexia. Ecstasy must be added to the list of potential causes
of acute hepatitis. Exposure must always be searched for in cases of acute
hepatitis in young subjects.
PMID- 9767972
TI - [Gammopathies of indeterminant significance and osteoporosis: association or
coincidence?].
AB - OBJECTIVES: Osteoporosis is common in subjects over 70 years of age. Likewise,
the incidence of monogammapathies of undetermined signification (MGUS) increases
with age. We conducted this study to determine whether the biological and
histomorphometric characteristics of osteoporosis in patients with MGUS are
different from those in primary osteoporosis and to ascertain whether any cause
and effect relationships could exist between MGUS and osteoporosis, excluding
signs of active myeloma. PATIENTS AND METHODS: Serum and urinary phosphorus and
calcium, histomorphometric measurements, hormone levels and serum cytokines (IL1,
IL6 and TNF alpha) were determined in 7 patients (mean age 71.8 years, 2 men and
5 women) with MGUS associated with osteoporosis with vertebral fractures (OP) and
compared with those in 7 osteoporosis patients without MGUS matched for age, sex,
and osteoporosis severity and 7 other age and sex matched patients with MGUS
without OS. The MGUS + PS patients were followed for 9 years (4.5 to 20) so
slowly progressive myeloma could be excluded. RESULTS: Cytokine levels were the
same in the three groups of patients but MGUS + OP patients had higher urinary
calcium levels (ca/cr = 0.21 +/- 0.08 vs 0.12 +/- 0.1 (OP) and 0.13 (MGUS); p =
0.04), decreased osteocalcin levels (7 +/- 4.6 ng/ml vs. 12 +/- 4 (OP) and 11.5
+/- 5 (MGUS); p = 0.01) and increased surface resorption (8 +/- 1.4 vs. 3.6 +/-
1.2 (OP) and 5.5 +/- 1.7 (MGUS); p = 0.05). DISCUSSION: It has been demonstrated
that MGUS in patients with increased resorption and lower osteocalcin levels
frequently progresses to active myeloma. The question is raised as to whether, in
certain cases of MGUS, in situ stimulation of bone cells by monoclonal plasma
cells could exist without ongoing transformation to active myeloma.
PMID- 9767973
TI - [Nephritic colic due to indinavir].
AB - OBJECTIVE: Evaluate the frequency and assess curative and preventive measures
against urinary lithiasis in patients treated with indinavir. PATIENTS AND
METHODS: Fourteen HIV seropositive patients who developed severe and acute flank
pain were included. Four of the patients receiving 800 mg indinavir t.i.d. had
fever (38.5 degrees C) or delayed secretion (> 2 h). Delay from indinavir
treatment onset was 1 to 321 days. During the same period, 155 patients had been
treated with indinavir. Clinical features, radiology and laboratory results were
recorded in addition to an analysis of the lithiasis if possible. RESULTS:
Transient moderate renal failure occurred in 8 patients. Mean urine pH was 6.
Serum phosphorus, calcium, and uric acid, liver tests and urinalysis were normal.
A JJ ureteral stent was inserted in 4 cases due to complications. In all cases,
fluids, analgesics and antispasmodics provided favorable outcome. Inversely,
nonsteroid antiinflammatory drugs given in 2 patients had a deleterious effect on
renal function. The lithiasis was eliminated in 3 cases and infrared
spectrophotometry demonstrated a structure compatible with indinavir monohydrate.
CONCLUSION: The formation of urinary lithiasis is a frequent complication of
indinavir therapy (9%). Hyperhydration and urine acidification are usually
successful but emergency drainage is required in approximately 3% of cases.
Nonsteroidal antiinflammatory drugs should be avoided due to the risk of renal
toxicity. A precise evaluation of fluid intake and diet, drug associations and
personal history is needed to recognize patients at risk of recurrent lithiasis
formation.
PMID- 9767975
TI - [Descending necrotizing mediastinitis. A diagnosis not to be ignored].
AB - BACKGROUND: Acute descending posterior mediastinitis is a very serious condition
which can develop after common ear-nose-throat infections. Clinical
manifestations are typical and must be recognized rapidly for early diagnosis.
CASE REPORTS: We report two cases. In the first case, a 28-year-old man had a
retropharyngeal abscess which fistulized into the left pleural cavity. Three
operations were necessary to achieve cure and favorable outcome. In the second
case, mediastinitis was diagnosed in a 39-year-old patient following a throat
infection. Despite early surgery, outcome was fatal due to development of
pericarditis and tamponnade. DISCUSSION: These two cases illustrate the variable
course of descending mediastinitis and emphasize the importance of early
medicosurgical cure. Treatment is based on intravenous antibiotics using a
combination of 2 or 3 drugs at high doses in association with emergency surgery
and extensive mediastinal washings. Despite well-conducted treatment, descending
necrotizing mediastinitis may lead to a fatal outcome.
PMID- 9767976
TI - [Reactive lymphadenopathy to wear debris of the hip prosthesis. Differential
diagnosis of pelvic lymphatic metastasis].
PMID- 9767978
TI - [Acute oligo-arthritis in a patient treated with BCG therapy for bladder
carcinoma].
PMID- 9767977
TI - [Subclinical cortisol-secreting adrenal adenoma. Follow-up over 5 years].
PMID- 9767979
TI - [The elderly in need].
PMID- 9767980
TI - [Acceptability and short-term tolerance to an orally administered new formulation
of magnesium (TX 1341) compared to that of a reference magnesium].
PMID- 9767981
TI - [Urinary incontinence in very elderly persons: health education improves access
to health care].
PMID- 9767982
TI - [Ramadan: the problem of tobacco].
PMID- 9767984
TI - [Anti-pneumococcal vaccination in elderly persons].
PMID- 9767983
TI - [Inflammation and joint destruction during rheumatoid polyarthritis: what
relation?].
AB - A QUESTION REVISITED: It is generally accepted that acute then chronic joint
inflammation leads to the development of a synovial pannus and secondarily to
characteristic degenerative joint disease en rheumatoid arthritis. However
accumulating clinical and biological evidence would question the real
relationship between inflammation and joint destruction, and suggest therapeutic
strategies might need to be revisited. THE CAUSAL EVENTS: Synovial proliferation
is the fundamental event in joint lesions. The contact between the synovial
pannus and the cartilage leads to characteristic joint damage mediated by pro
inflammatory cytokines (TNF alpha and IL 1) and enzyme secretion, particularly
metalloproteases. ROLE OF T CELLS: The role of T-lymphocytes is a question of
much debate. Although it is generally accepted that T cells are crucial in the
initial phases of rheumatoid arthritis, several arguments suggest that the
process of synovial proliferation and joint destruction in advanced stage disease
would be independent of T cell activity. Synovial macrophages and fibroblasts,
and perhaps chondrocytes, play a central role at this phase. THERAPEUTIC
IMPLICATIONS: A direct mandatory relationship between inflammation and joint
destruction appears to be excluded, although complex and poorly understood links
exist between these events in rheumatoid arthritis. A better understanding of the
mechanisms involved would be very useful for the development of more adapted
therapeutic strategies in rheumatoid arthritis.
PMID- 9767986
TI - [Cardiorespiratory effects of laparoscopic surgery].
PMID- 9767985
TI - [Primary pulmonary arterial hypertension].
PMID- 9767987
TI - [Severe gastrointestinal hemorrhages].
PMID- 9767988
TI - [Ambulatory surgery in children: practical aspects for the anesthetist].
PMID- 9767989
TI - [Postoperative thromboembolic disease. Prevention, diagnosis, treatment].
PMID- 9767990
TI - [Rules of preoperative antibiotic prophylaxis prescription].
PMID- 9767991
TI - [Malignant anesthesia hyperthermia].
PMID- 9767992
TI - [Preoperative management of subjects at risk].
PMID- 9767993
TI - [Preoperative management of subjects at risk. Asthmatic patients].
PMID- 9767994
TI - [Preoperative management of subjects at risk. Diabetic patients].
PMID- 9767995
TI - [Preoperative management of subjects at risk. Obese patients].
PMID- 9767996
TI - [Extrapulmonary tuberculosis in the central western region. Retrospective study
of 217 cases (Gericco 1991-1993)].
AB - OBJECTIVES: To analyze the epidemiological, clinical and diagnostic
characteristics of extrapulmonary tuberculosis in western France observed from
1991 to 1993 in different patients populations (HIV+ infected patients,
immunosuppressed non-HIV infected patients, non-immunosuppressed patients) and
according to various localizations (lymph nodes, bone and joints, genital organs,
nervous system and meninges, miliary disease). METHODS: This retrospective study
included 217 cases of extrapulmonary tuberculosis diagnosed from 1991 to 1993 in
western France by GERICCO (Groupe d'Epidemiologie et de Recherche en
Infectiologie Clinique du Centre-Ouest). Demographic, clinical, biological,
microbiological and radiographic characteristics as well as clinical course on
specific therapy were assessed. RESULTS: Extrapulmonary tuberculosis generally
occurred most often in immunosuppressed patients but 34% of cases were observed
in people without any underlying disease or risk factors. Delay to diagnosis was
especially long in the non-immunosuppressed patients (mean = 96 days) but shorter
in the HIV-infected patients (mean = 59 days). It was shorter in case of nervous
system involvement (mean = 52 days) or military disease (mean = 80 days) than in
bone and joints (mean = 120 days) and lymph nodes (mean = 102 days).
Microbiologically proven tuberculosis represented only 75% of cases despite
numerous investigations. Overall prognosis was good except in nervous system and
meninges localizations. Failures were mainly due to death in immunosuppressed
patients. CONCLUSION: Extrapulmonary tuberculosis remains frequent even in
patients lacking risk factors. In 50% of cases, confirmation of diagnosis takes
more than one month. In case of doubt, clinicians should not wait for laboratory
results before implementing empirical specific therapy.
PMID- 9767997
TI - [Ambulatory surgery in French public hospitals. Present and future. "Public
hospitals" group of the French Association of Ambulatory Surgery].
AB - OBJECTIVES: To assess ambulatory surgery practices in France, make an inventory
of projects for the creation of ambulatory structures and analyze the perception
of different hospital personnel of ambulatory surgery. METHODS: A questionnaire
was sent to 541 public hospitals with a surgery unit in France. The first part of
the questionnaire was used to record current activity and existing projects for
ambulatory surgery. The questionnaire also collected opinions concerning the
analysis of difficulties encountered and possibilities offered by ambulatory
surgery. RESULTS: Overall participation rate was 59%. Ambulatory surgery was
practised in 81% of the hospitals. Sixty-six percent had a projects under
consideration, including several at the decision making stage (17%). 1550
ambulatory surgery clinics could be created by the year 2000. In 66% of the
cases, the future facility would be integrated into the traditional surgery unit.
There was favorable opinion concerning the development of ambulatory surgery
clinics in public hospitals in 83% of the cases. Inconveniences suggested
generally involved organizational aspects, particularly concerning medical
organization. Foreseen obstacles to the development of ambulatory surgery clinics
were regulatory procedures, unfavorable exchange rate, insufficient investment
funds and the lack of a policy favoring their development. CONCLUSION: The
development of ambulatory surgery clinics in public hospitals in France can be
expected in the near future. Budgeting and regulatory procedures must however be
adapted to promote implementation of the existing projects.
PMID- 9767998
TI - [Late manifestation of common variable immunodeficiency by Biermer's disease].
AB - BACKGROUND: Common variable immunodeficiency (CVI) is a heterogeneous disorder
characterized by decreased production of antibodies. Clinical presentation of CVI
is generally that of recurrent pyogenic infections. Autoimmune diseases can also
occur. The age of onset of symptoms shows two peaks at 1-5 and 16-20 years. CASE
REPORT: A 77-year-old man was admitted in hospital for pernicious anemia. We
discovered hypogammaglobulinemia with low levels of immunoglobulin G, A and M,
but normal T-cell levels. We diagnosed common variable immunodeficiency. This
patient had not had recurrent pyogenic infections. DISCUSSION: This case shows
that common variable immunodeficiency can be revealed late by an autoimmune
disease. The pathogenesis of autoimmune diseases in this immunodeficiency remains
unknown despite several possible explanations.
PMID- 9768000
TI - [Campylobacter fetus endocarditis manifested by a popliteal mycotic aneurysm].
AB - BACKGROUND: Campylobacter fetus endocarditis is uncommon and may be life
threatening. CASE REPORT: A 91-year-old patient with rectal villous
adenocarcinoma was admitted with fever and recent complaints of popliteal pain.
The definite diagnosis of endocarditis and mycotic aneurysm related to C. fetus
infection were accepted on the basis of clinical, radiological and
microbiological data. Cure was achieved with antibiotics and surgery of the
aneurysm without valvular replacement. DISCUSSION: C. fetus endocarditis was
probably secondary to the iterative laser treatment of the rectal tumor that had
been performed during the past weeks without antibiotic prophylaxis.
PMID- 9767999
TI - [Value of magnetic resonance cholangiography in the diagnosis of common bile duct
cystic dilation].
AB - BACKGROUND: Magnetic resonance cholangiography is a noninvasive method for
exploring the biliary and pancreatic ducts. Allergic risk is reduced as no
contrast agent is required and there is no risk of infectious contamination due
to catheterism. Unlike endoscopic retrograde cholangiography which requires
anesthesia, there is no risk of morbidity. We report one observation of Todani
type Ia cystic dilation of the main bile duct explored preoperatively with MR
cholangiography. CASE REPORT: A 39-year-old woman complained of acute abdominal
pain. Physical examination revealed jaundice and fever. MR-cholangiography gave
the diagnosis of angiocholitis with cystic dilatation of the main bile duct (type
Ia). Surgery was indicated. The procedure included a Y-loop hepato-jejunal
anastomosis and cholecystectomy. The postoperative period was uneventful.
Pathology reported a cystic formation with no signs of malignancy. DISCUSSION:
Common manifestations of congenital cystic dilatation of the main bile duct are
biliary pain, fever and jaundice. The MR-cholangiogram provides a map of the bile
duct system directly with a noninvasive procedure. The map may be obtained in
several planes to guide surgery. Indeed, since cholangiocarcinoma is found in
numerous cases, surgery is a formal indication in patients with angiocholitis.
PMID- 9768001
TI - [Palinopsia in Charles Bonnet syndrome].
PMID- 9768002
TI - [Laparoscopic adrenalectomy in pheochromocytomas].
PMID- 9768003
TI - [Weak antiviral effect of changing two nucleoside analogues combined with
antiretroviral agents. 3TC and d4T after ZDU and ddi or ddc].
PMID- 9768004
TI - [Fragility of scientifically acquired data. The example of fluoride salts in
osteoporosis].
AB - Although there is a pathophysiological rationale for the use of sodium fluoride
for the treatment of postmenopausal osteoporosis and a long history of clinical
trials, there is no evidence today of its clinical efficacy. The use of sodium
fluoride was a long-standing practice for many years which became official policy
when strong scientific arguments suggested its efficacy. The lack of
methodologically solid evidence however raised some doubts, echoed by the
regulatory authorities, and led to a re-evaluation. The unacceptable risk/benefit
ratio demonstrated by the new results was a major scientific event giving the
scientific community a concrete example of why evidence provided by clinical
research must be regularly revisited.
PMID- 9768005
TI - [Medicine of care as seen by Cuvier in 1808].
PMID- 9768006
TI - [Genomic imprinting].
AB - AN EXCEPTION TO THE RULE: For certain genes, alleles are expressed differently
depending on whether they originate from the maternal or paternal genome. This is
called the parental imprinting. The parental imprinting plays an important role
in development and a dysregulation can lead to various disease states. Loss of
the parental imprinting or its alteration is implicated in certain genetic
diseases and cancers. When the process is altered, two homologous chromosomes may
come from the same parent, a situation termed uniparental disomy. GENETIC DISEASE
IN MAN: Several genetic diseases in man are known to be related to the parental
imprinting. Willi-Prader disease, Angelman disease and Beckwith-Wiedemann disease
are the most extensively studied. MECHANISMS: Some of the underlying mechanisms
are known, but several points concerning the parental imprinting remain to be
elucidated, particularly the precise nature of the molecular mechanisms and the
identification of the genes controlling this genetic process.
PMID- 9768007
TI - [Diagnosis and management of parasitic hypereosinophilia].
AB - ETIOLOGY: Helminth infestation of the digestive tract or organ tissues is a
common and curable cause of high eosinophil counts. Parasite infestation should
be the number one suspect in patients with hypereosinophilia. DIAGNOSIS: Clinical
signs and epidemiology are suggestive. If the patient has travelled to the
tropics, one should consider both exotic and cosmopolite parasites. LABORATORY
TESTS: The causal agent can sometimes be identified by direct examination of
tissue samples, depending on the localization. In practice however identification
may be a difficult task when the level of infestation is low or the helminth is
in a larval stage. The epidemiological situation, clinical features and results
of serology tests must all be considered for diagnosis. ANTIHELMINTH TREATMENT
(TEST): Clinical improvement after treatment can be a criteria for positive
diagnosis. Normal eosinophil counts followed later by normal serology confirms
the diagnosis.
PMID- 9768008
TI - [Hereditary neurological diseases caused by amplification of triplet
repetitions].
AB - NEW TYPE OF MUTATION: Repeated sequences of nucleotide triplets can cause two
groups of diseases. GROUP I DISEASES: These diseases result from an expansion of
a noncoding portion of a gene which may be repeated more than 1000 times. This
group includes several multisystem diseases such as the fragile X syndrome and
its variants, Steinert's disease and Friedreich's disease in which nervous system
disorders are not always predominant. The molecular mechanism of the cellular
disorder is probably related to a nonfunctional abnormal protein. GROUP II
DISEASES: Huntington's disease, spinobulbar amyotrophy or Kennedy's disease,
dentato-rubo-pallidolusian atrophy and spinocerebellar ataxias 1, 2, 3, 6, and 7
are characterized by local expansion of the coding part of a gene. This low
amplitude expansion always involves the CAG triplet and leads to expression of a
protein with an abnormal number of glutamines, producing typical
neurodegenerative disease almost exclusively limited to the nervous system. The
underlying mechanism of the neuronal suffering is probably the production of an
abnormal but functional protein. The causes of this type of mutation remain
unclear. PERSPECTIVES: Positive diagnosis is now possible with DNA sequencing.
While antenatal diagnosis offers essential information for family genetic
counselling there is no perspective of therapeutic propositions for the near
future. The problems raised by presymptomatic diagnosis must not be
underestimated.
PMID- 9768009
TI - [Lung cancer in patients infected with human immunodeficiency virus. Clinical
course and therapeutic implications].
AB - OBJECTIVES: HIV infection is associated with increased frequency of non-Hodgkin's
lymphoma and Kaposi sarcoma. Like other malignancies, lung cancer has been
described in HIV-infected patients although no evidence of a statistical
correlation has been reported. PATIENTS AND METHODS: We performed a retrospective
analysis of 15 HIV-infected patients with lung cancer. The patients were
relatively younger (mean age 45 years) than is commonly found in lung cancer
cohorts. RESULTS: The 15 patients had mild immunodepression (240 CD4+/mm3) and
were in advanced clinical stage at diagnosis. Mean overall survival was 6 months
and no clinical or biological prognostic factors were found. Death was usually
due to infection, suggesting a synergetic effect between HIV and chemotherapy
induced immunodepression. CONCLUSION: We propose early antiretroviral therapy in
cases of chemotherapy-treated HIV patients, even when commonly accepted
immunological and/or clinical criteria are absent.
PMID- 9768010
TI - [Cholera in a Paris resident with no history of travel. A case report].
AB - BACKGROUND: Cases of imported cholera are frequently observed, but cholera almost
never occurs in subjects who have never travelled to an endemic area. In the last
30 years, 4 cases have been reported. We report an indigenous case diagnosed in
Paris in September 1996. CASE REPORT: The patient was hospitalized for severe
dehydration and acute renal failure. Cultures of a fecal specimen grew Vibrio
cholerae O1 Ogawa serotype. An epidemiological study was conducted to identify
the vehicle and mode of contamination and suggested that this case was associated
with the consumption of fresh sorrel imported from West Africa. No other cases
were identified in contacts of the patient. DISCUSSION: Asymptomatic carriage of
V. cholerae is rare. However, air travel has allowed people to arrive in non
endemic areas during the incubation period. The agent may also be transported in
contaminated foods. Cholera should be suspected in all adults presenting acute
watery diarrhea with severe dehydration. History taking should also look for risk
exposure and these patients should be systematically asked about possible
exposures.
PMID- 9768011
TI - [Pulmonary embolism of hydatic origin].
AB - BACKGROUND: The right ventricle is an exceptional localization for hydatic cysts.
There is a risk of hydatic embolism and chronic or acute cor pulmonale. CASE
REPORT: A 63-year-old-man with an uneventful history was hospitalized for dry
cough, exercise-induced dyspnea and bloody expectorations which had developed
over the previous year. Multiple and bilateral opacities were visualized on the
standard chest x-ray and the right border of the heart showed a bulge in the
middle portion. Signs of right-sided hypertrophy were seen on the ECG. Imaging
findings led to the diagnosis of multiple organ hydatiasis involving the lung,
the liver the mediastinum and a ruptured hydatic cyst in the right ventricle. The
cavogram revealed defect images in the superior vena cave and the pulmonary
angiogram confirmed the diagnosis of hydatic embolism. Medical treatment was
given but the patient died 8 months after diagnosis. DISCUSSION: Hydatic
pulmonary embolism generally occurs after rupture of a hydatic cyst in the right
ventricle or due to venous migration of daughter vesicles to the right heart then
the pulmonary artery. Clinical manifestations are not specific although hemoptisy
is the most frequent sign. Positive diagnosis, guided by echocardiographic
findings, is based on the pulmonary arteriogram. Prognosis is particularly poor
and depends of the patient's general status as well as the number and size of the
embolized vessels. Survival rate is poor. Open heart surgery is indicated in
localized forms.
PMID- 9768012
TI - [Birth defect of the coronary arteries].
PMID- 9768013
TI - [Late manifestation of GM1 gangliosidosis in an adult. An unusual case of
multiple sclerosis].
PMID- 9768014
TI - [Splenic hematoma during infectious mononucleosis: non-operative treatment].
PMID- 9768015
TI - [Assessment of the placebo effect of symptomatic slow-acting anti-arthritics].
AB - OBJECTIVES: Assess the importance of the mid-term placebo effect of symptomatic
slow acting drugs given for osteoarthritis. METHODS: We analyzed six controlled
trials available in the literature. Trial duration ranged from 2 to 6 months. The
trials had been conducted to assess the symptomatic effect of diacerhein,
avocado/soya unsaponifiable chondrontin sulfate and oxaceprolin given for
osteoarthritis of the hip or knee. The main clinical outcomes assessed were
functional impairment using the Lequesnes index and a visual analog scale.
RESULTS: Globally, the trials showed decreased function impairment with a 2 to 3
points decrease in the Lequesnes index (15 to 20%) and a 10 to 16 mm fall in the
visual analog scale (-20 to -30%) in the placebo groups. CONCLUSION: Our findings
confirms the importance of the mid-term placebo effect in the clinical course of
osteoarthritis in patients given slow-acting drugs. This placebo effect, observed
under these circumstances, is an expression of what clinicians will look for in
future drugs and should be helpful for calculating the number of patients
required in future trials.
PMID- 9768016
TI - [Continuous intrathecal baclofen in a case of generalized tetanus].
PMID- 9768017
TI - [Idiopathic calcium lithiasis. Dietary correction of metabolic risk factors.
Physiopathological bases].
PMID- 9768018
TI - [Idiopathic calcium lithiasis. Diuresis treatment].
PMID- 9768019
TI - [Idiopathic calcium lithiasis. Practical guide for dietary measures
prescriptions].
PMID- 9768020
TI - [Echo Doppler classification of postoperative recurrence of varicose veins in the
region of the internal saphenous vein].
AB - OBJECTIVES: Surgical treatment of varicose veins of the lower limbs is frequently
complicated by recurrence. Although recurrence was long thought to result from
technical errors, certain patients have progressive disease. METHODS: We used
duplex-Doppler to assess 102 patients (160 limbs) with recurrence after resection
of the saphene-femoral junction with stripping of the internal saphenous vein and
the varicose network on the medial aspect of the leg. A vein map was established
to classify recurrences. RESULTS: Type I, junctional stump with incontinent
collateral, was observed in 22.5% of the cases. Type II, sapheno-femoral junction
in an anatomic position, was found in 18.1%. Type III, backward flow from a
perforating vein or a collateral of the common femoral was found in 13.1% and
type IV, cavemomous aspect, in 7.5%. In 45% of the cases, the patient had a
progressive condition with backward flow from collateral branches in the perineal
or inguinal area unconnected to the common femoral. DISCUSSION: The cause of
recurrent varicose veins is a question of debate: inadequate or incomplete
treatment versus disease progression. Due to the chronic and evolutive nature of
varicose veins, duplex Doppler exploration is essential for the preoperative work
up. Follow-up examinations should also be performed every year when the clinical
examination suggests recurrence.
PMID- 9768021
TI - [Improvement of prescriptions for serum tumor markers in a general hospital].
AB - OBJECTIVES: Using a standardized prescription sheet we attempted to improve
requests for serum tumor markers in a general hospital. METHODS: Over two 35-day
periods before and one year after defining a local prescription consensus and
introducing a new prescription sheet, we counted the number of orders for five
tumor markers (CEA, CA 19-9, CA 15-3, CA 125, alpha FP) and determined their
compliance to the defined prescription protocol. RESULTS: Between the two study
periods, the number of prescriptions for the designated tumor markers fell by
24%, from 153 requests in 94 patients to 123 requests in 99 patients, despite a
6% increase in the number of admissions. There was a significant reduction in the
number of serum markers orders per prescription (from 1.6 to 1.2) although the
distribution by tumor marker remained unchanged. Compliance to the prescription
protocol improved, rising from 65 to 87% in units where the pre-protocol
compliance rate was below 80%. The rate of compliance was not correlated with
correct completion of the new prescription sheet (91% vs 86% respectively). The 6
month cost-savings was estimated at 31,104 FF using the general French
nomenclature for laboratory tests. Direct cost reduction was estimated at 5,688
FF. CONCLUSION: Long-lasting improvement of serum tumor marker prescriptions can
be achieved in a general hospital. Obtaining a local consensus implicating all
prescribing units seems more important than a change in the presentation of the
prescription sheet.
PMID- 9768022
TI - [Stromal tumors in the digestive tract. A case of duodenal localization].
AB - BACKGROUND: Stromal tumors of the digestive tract are undifferentiated connective
tissue tumors which are difficult to characterize even with immunohistochemistry.
CASE REPORT: A stromal tumor of the duodenum (the most frequently encountered
location) was resected entirely. Histochemistry was unable to provide a precise
identification of the histological nature. The tumor was considered to be low
grade due to the low mitosis index despite its large size and the presence of
necrosis. Careful surveillance was indicated. DISCUSSION: The risk of these
tumors is uncertain and may be assessed on the basis of histological prognosis
factors such as tumor size, mitosis index and ploidy. Echoendoscopy can be
particularly useful for diagnostic purposes providing information on location in
the duodenal musculosa.
PMID- 9768023
TI - [Splenic rupture revealing Waldenstrom disease].
PMID- 9768025
TI - [Transient vascular accident, possibly related to intravenous immunoglobulins].
PMID- 9768024
TI - [Acanthamoeba keratitis].
PMID- 9768026
TI - [HIV seroconversion revealed by agranulocytosis].
PMID- 9768027
TI - [Postpartum venous thrombosis. Differential diagnosis of postpartum anesthetic
complications].
PMID- 9768028
TI - [Trans-cervical collection of embryonic cells].
PMID- 9768029
TI - [Acrosyndromes in AIDS].
PMID- 9768030
TI - [Fracture of the sacrum caused by bone deficiency].
PMID- 9768031
TI - [Compassion for pregnant women].
PMID- 9768032
TI - [Quality and accreditation in health establishments. Application of experience
acquired in the industrial setting].
PMID- 9768033
TI - [Organ donation in France. Current situation and perspectives].
AB - RECENT CRISIS: Strict legal regulations concerning human organ procurement in
France emphasize the positive aspect of donation. While public opinion in France
is generally favorable, organ donation passed through a crisis during the period
between 1990 and 1994. The media played a crucial role. CONFIDENCE AND
COORDINATED EFFORTS: The Etablissement francais des Greffes, in coordination with
health care workers and non-governmental organizations, has developed a wide
health education program aimed at gaining the confidence of the public and
organizing hospital efforts to create an effective and serene procurement
procedure. PERSPECTIVES: Procurement of cadaver organs remains essential despite
the number of living-donors and ongoing development of artificial organs and
xenografts.
PMID- 9768034
TI - [Treatment of refractory spondylarthropathies].
PMID- 9768035
TI - [Therapeutic management of cytomegalovirus infection in HIV-infected patients.
Curative and pre-emptive treatment: results and uncertainties].
PMID- 9768036
TI - [Kaposi disease].
PMID- 9768038
TI - [Transesophageal echocardiography before electric cardioversion for
supraventricular arrhythmia].
AB - OBJECTIVES: The aim of this prospective study was to assess the risks of
electrical shock cardio-version in the treatment of supraventricular rhythm
disorders when administered under effective-dose but short duration
anticoagulation in patients with no intracavitary thrombus detectable by
transesophageal echocardiography. PATIENTS AND METHODS: One hundred nineteen
patients, mean age 66 years, with permanent arrhythmia due to atrial fibrillation
(n = 102), atrial flutter (n = 16) or atrial tachycardia (n = 1) and taking no
long-term anticoagulant therapy were treated by electrical shock cardioversion.
The patients were given heparin at an effective dose 72 hours prior to
cardioversion. A transthoracic and a transesophageal echocardiography were
performed less than 24 hours prior to cardioversion. RESULTS: Twenty-one thrombi
were evidenced in 16 patients (14.6%) including 18 in the left auricle, 1 in the
left atrium and 2 in the right atrium. A spontaneous contrast was visualized in
38 patients (32%). Cardioversion was performed in 103 patients without thrombus
and later in 9 of the 16 patients with thrombus after absorption under
anticoagulant therapy as evidenced on the control transesophageal
echocardiography. A sinus rhythm was obtained in 82% of the cases. All patients
were given anti-vitamin K anticoagulants for one month. There were no clinical
manifestation of ischemic vascular events during cardioversion nor during the one
month follow-up. CONCLUSION: Early use of electrical shock cardioversion in
patients with supraventricular rhythm disorders can be proposed without long-term
anticoagulation therapy if the absence of thrombi is demonstrated by
transesophageal echocardiography and short-term heparin is given followed by oral
anticoagulants for at least 4 weeks. A large-scale randomized prospective study
comparing the conventional strategy with the protocol used in this study would be
required to definitively validate this approach and determine its possible
advantages.
PMID- 9768037
TI - [Prevention of venous thromboembolism. Survey of in-hospital medical practice].
AB - OBJECTIVES: In an effort to improve the prevention of venous thromboembolism, the
Nancy University Hospitals conducted a survey of medical practice concerning
indications for preventive therapy and surveillance of platelet counts and anti
Xa activity. METHODS: The survey involved 163 medical files. Questionnaires were
filled out in 6 units (3 medical wards and 3 intensive care units). RESULTS:
Indications for preventive therapy were found to be quite variable with the
exception of very low risk of thromboembolism where the treat/do not treat ratio
was 0.1/1, indicating a clear tendency for abstention. This ratio was 0.77/1 and
0.38/1 respectively for low and moderate risk and 2/1 for high risk. There was
undoubtedly a ward effect. The attitudes in practice tended toward non-prevention
in patients without limited mobility. For platelet counts, an initial count was
performed in 95% of the cases and during treatment in 38% although the specific
rates were not the same for different types of units. Anti-Xa activity, which
according to prevention recommendations need not to be determined, was not
monitored in 88% of the cases. In accordance with prevention recommendations,
anti-Xa activity was not determined in 88% of the cases. CONCLUSION: Further
progress is needed in the prevention of venous thromboembolism and should be
based on wider use of existing methods.
PMID- 9768039
TI - [Group A Streptococcus pyomyositis].
AB - BACKGROUND: Pyomyositis is a group of infectious diseases involving muscle
tissue. Staphylococcus aureus is usually the causal agent. Group A Streptococcus
infections are uncommonly isolated in pyomyositis. Streptococcal pyomyositis can
be distinguished by its severity. Death rate may be as high as 50%. CASE REPORTS:
Diagnosis of cervical pyomyositis was made in 2 patients on the basis of
ultrasound and computerized tomography findings. Group A Streptococcus was
isolated from local samples. The diagnosis was confirmed at surgery. Host defense
mechanisms were not deficient in either patient. Outcome was favorable in both
patients after antibiotic therapy. DISCUSSION: Because of the seventy of group A
streptococcal pyomyositis, early diagnosis is essential for prognosis. Ultrasound
and computerized tomography are very helpful. Group A streptococcal pyomyositis
should be considered as a life-threatening disease.
PMID- 9768040
TI - [Lung abscess caused by Pasteurella multocida, an unexpected germ...].
PMID- 9768041
TI - [Cyst of the cruciate ligament of the knee. Treatment by simple radio-guided
puncture].
PMID- 9768042
TI - [Effect of corticotherapy on the course of a severe form of Nelson syndrome].
PMID- 9768043
TI - [Treatment of malaria: let us be sensible!].
PMID- 9768044
TI - [To everyone their own phantoms].
PMID- 9768045
TI - [Drugs on the Internet. Hazards of public health].
AB - The development of internet and more generally of telematics has given rise to
many practical consequences in medicine. Whatever the context (communication,
medias, teaching, imaging or data transmissions), Internet appears as a familiar
tool in many medical fields. However some drift with harmful consequences for
public health is emerging. This is particularly true for drugs sales via
Internet. The absence of any control by health authorities over Internet drug
sales raises acute legal problems for jurists, pharmacists, pharmacologists and
public health physicians. A debate on the main difficulties is urgently needed.
PMID- 9768046
TI - [Extracorporeal photochemotherapy: a new approach to immunosuppression in
transplantation].
PMID- 9768047
TI - [Current diagnostic procedure in aortic dissection].
PMID- 9768048
TI - [Resection of hepatic metastases from colorectal cancer].
PMID- 9768049
TI - [Tomodensitometric image of the lumbar spine. Study of 150 patients hospitalized
for discal sciatica].
AB - OBJECTIVES: There would be some discordance between patient expectations and
expert recommendations concerning computed tomography (CT) of the spine for
discal disorders. We analyzed patient opinion. PATIENTS AND METHODS: At
admission, a 25-item questionnaire was given to 150 patients hospitalized in a
rheumatology unit for discal sciatica. Patients were asked to express their
expectations concerning the CT exploration. RESULTS: Seventy percent of the
patients had already undergone CT explorations requested by a general
practitioner (55%) or a specialist (45%), 20% had had two CT explorations and 20%
magnetic resonance imaging. Seventy-five percent felt they should have had a CT
scan earlier, 85% thought a CT should be performed for back pain of less than one
month duration and 96% in case of sciatica for 2 months or more. Patients felt
their exploration came "late" because the physician was under financial pressure
(52%), had incorrectly appreciated the patient's need (28%) or was incompetent in
the matter (22%). Nevertheless, 15% of the patients recognized that the CT scan
could be useless and 89% knew that all cases of hernia are not operable. Thirty
percent recognized that hernias can go undetected on the CT scan and 78% that
they may remain asymptomatic. Finally, 56% of the patients thought that the CT
scan would not change their treatment and only 23% expected to undergo surgery
sooner because of the CT exploration. DISCUSSION: Several factors would explain
what patients expect from CT exploration of the spine: patient understanding that
causes other than discal hernia can cause back pain (98%) or sciatic (77%); their
fear of having another disorder (56% wanted to be reassured, which would explain
in part why 27% hoped the CT would improve pain, 50% wanted to "see" their discal
hernia, and 30 wanted to eliminate another cause of their pain); patient distrust
of clinical diagnosis which they felt was less pertinent than CT (80% of the
patients for generalists and 70% for specialists). Patient expectations did not
appear to be limited by fear of irradiation (unrecognized by 90% of the patients)
nor the cost of the exploration which was overestimated by 70% of them.
PMID- 9768050
TI - [Lead blood levels in children under 6 years of age in the Mans region].
AB - OBJECTIVES: High lead levels in children can have a deleterious effect on
intellectual development. We assessed blood lead levels in children in the Le
Mans region. METHODS: Children aged between 6 months and 6 years were included in
the study. Inclusion criteria were health status requiring a blood sample and
amount of blood available after ordered tests sufficient for lead blood analysis.
The study group included 365 children. RESULTS: Mean blood level in the 365
children was 37.2 +/- 20.6 micrograms/l. Six of the children had blood levels
greater than 100 mu/l. None of the children had a level over 200 micrograms/l.
Location of the home or date of construction of the home were not significantly
correlated to blood lead levels, however blood lead levels were higher in
children with neurological or behavioral disorders. This observation was made in
a limited number of children. CONCLUSION: The risk of excessively high blood lead
levels in children under 6 years of age is low in the Le Mans region. There is
however a risk when old houses are renovated or in children with neurological or
behavior disorders.
PMID- 9768051
TI - [Nephrotic syndrome revealing malignant thymoma].
AB - BACKGROUND: A well-established manifestation of neoplastic disease, nephrotic
syndrome is infrequently associated with thymoma. Only 18 cases have been
reported in the literature. CASE REPORTS: A 65-year-old man and a 60-year-old
woman were seen for nephrotic syndrome. Minimal change renal disease was observed
in the first patient whose nephrotic syndrome was steroid resistant. The second
patient had membranous glomerulopathy and pure red cell aplasia. In both cases,
nephrotic syndrome revealed thymoma. DISCUSSION: The histological lesions in 17
of the 18 biopsied cases reported in the literature were minimal change in 10,
focal segmental glomerulonephritis in 4, proliferative glomerulonephritis in 2,
and membranous glomerulopathy in only one. The outcome of the nephrotic syndrome
was dependent on the success of the thymoma treatment. Some patients responded to
steroid and immunosuppressive agents. Pure red cell aplasia is uncommon and
prognosis is poor. It can be successfully treated with cyclosporin A as in our
second case.
PMID- 9768053
TI - [Thrombosis of the superior vena cava, hemolytic anemia and hyper
homocysteinemia].
PMID- 9768052
TI - [Interferon alpha and pamidronate: a useful combination in the treatment of
osteoporosis and systemic mastocytosis].
PMID- 9768054
TI - [Acute severe colitis induced by cytomegalovirus in an immunocompetent patient
who underwent several blood transfusions].
PMID- 9768055
TI - [Median HIV viral load and incidence of Cytomegalovirus viremia. Improvement in a
cohort of HIV-infected patients followed-up between January 1996 and April 1007].
PMID- 9768056
TI - [At the National Academy of Medicine. Presentation of the noxious effects of
ultraviolet rays].
PMID- 9768057
TI - [Failure of anti-pneumococcal vaccination in a splenectomized patient with HIV
infection].
PMID- 9768059
TI - [Arthrosis: a disease of the future].
PMID- 9768058
TI - [Newly discovered role of glomerulonephritis mediators].
PMID- 9768060
TI - [Physiopathology of arthrosis. The normal cartilage].
PMID- 9768061
TI - [Physiopathogenesis of osteoarthritis. The arthritis cartilage].
PMID- 9768062
TI - [Physiopathogenesis of arthrosis. Therapeutic perspectives].
PMID- 9768063
TI - [Method of esthetic evaluation of the reconstructed breast after cancer. Report
of 76 cases].
AB - The authors propose a simple method of aesthetic evaluation of breast
reconstructions after cancer, based on a 20-point score. In the 76 patients
included in this study and mainly reconstructed by implant, the following seven
criteria were evaluated by a score: the reconstructed breast, the symmetrized
breast, symmetry of the 2 breasts, the areola, the nipple, the areolo-nipple
complex (ANC) and the overall reconstruction. The first score was established
during the visit by the patient and independently by the same plastic surgeon.
The score was then established during two sessions of projection of standardized
photographs, by two groups, A and B, composed of 9 nurses and secretaries and 10
plastic surgeons, respectively. Statistical analysis of the results showed that
the scores for these criteria were all correlated for all examiners. This study
confirms the reliability of aesthetic evaluation of breast reconstruction after
cancer, by a group composed of 2 men and 2 women, surgeons or non-surgeons, on
photographs or on clinical examination, based on a 20-point score.
PMID- 9768064
TI - [Prospective study of 100 cases of breast hypertrophy].
AB - The authors performed a prospective study of 100 consecutive cases of mammary
hypertrophy. Sixty were treated by McKissock's technique and forty by Thorek's
technique. The patients were reviewed at the second and sixth postoperative
months. A general study of the population was performed to specific their demand,
which was functional in 90% of cases, and the various symptoms were quantified.
74% of cases presented with psychological problems and a desire for aesthetic
improvement was expressed by 67% of cases. Postoperatively, a functional
improvement was obtained in 99% of cases, while psychological disorders resolved
in 100% of cases. The satisfaction rate was very high: 79% of patients were very
satisfied and 20% were satisfied. Some defects observed by the patients or
surgical team are analysed. The complications observed, always minor, are
reported. Breast reduction provides an unquestionable benefit for patients with
mammary hypertrophy. Two simple and perfectly defined techniques were used to
treat all these cases with a maximal satisfaction rate and a minimal complication
rate.
PMID- 9768065
TI - [Treatment of fibrous dysplasia of the cranio-facial bones. Report of 25 cases].
AB - Fibrous dysplasia accounts for approximately 2% of bone tumors. The ribs,
proximal femurs and cranio-facial bones represent the majority of bone lesions.
Surgery is the mainstay of treatment but the technique is controversial:
conservative surgery or removal of dysplastic lesions followed by implantation of
autogenous bone graft. The aim of this study was to assess the indications of
each method. The medical records of 25 patients with fibrous dysplasia of the
cranio-facial bones treated between January 1, 1980 and December 31, 1994 at the
Department of Maxillofacial Surgery, Centre Hospitalier Universitaire de
Bordeaux, France, were reviewed. Fourteen (56%) patients were women and 11 (44%)
men. The median age at the time of diagnosis was 23 years (ranging from 8 to 56
years). The mean follow-up was 8 years. Two patients were unavailable for follow
up after treatment. The primary sites of the tumors were the mandible (n = 19
[76%]), maxilla (n = 1 [4%]) and skull (n = 5 [20%]). For mandibular lesions, the
primary treatment always included a correction of deformations and asymmetry,
which was the only treatment in 14 cases. Two patients required subsequent
surgery to reduce further bone enlargement (1 and 2 years later in the first case
and 11 years later in the second) without further problems. In 3 cases a
segmental mandibulectomy followed by implantation of autogenous bone graft was
required, and no further recurrence was observed. Therefore, the success rate of
conservative surgery was 74% initially, and up to 86% after subsequent surgery.
Skull lesions, although often very extensive, were remarkably stable and
asymptomatic. They were successfully treated 4 times by conservative surgery,
mainly for cosmetic reasons. One patient, with an ethmoidal tumor producing a
mass effect along the course of the optic nerve, underwent a combined cranio
facial resection. As for the only maxillary tumor, three curettages were
performed throughout an 11-year period and there was no evidence of further
recurrence 4 years after the last intervention. In all cases, conservative
surgery may be recommended as primary treatment of fibrous of the craniofacial
bones, providing essential structures like the optic nerve are not at risk.
Cosmetic results and local control proved excellent, and a further removal of the
tumor remained feasible in the event of a recurrence. Success or failure did not
correlate with tumor size, which justifies the use of this technique.
PMID- 9768067
TI - [Submental endotracheal intubation in craniomaxillofacial trauma. Technical
note].
AB - Submental intubation is a new technique of oroendotracheal intubation in patients
with facial fracture requiring jaw control, associated with skull base fracture.
First described by Altemir in 1986, the simplicity of this procedure and its
minimal scar traces lead the authors to prefer it to tracheostomy in patients who
do not need endotracheal intubation for more than 48 hours.
PMID- 9768066
TI - [Secondary rhinoplasty for unilateral cleft lip and palate. Review of the
literature and 50 clinical cases].
AB - The nasal sequelae of unilateral cleft lip and palate are almost always present:
more or less severe deformities, essentially consisting of nostril deformity and
deviated septum. After an anatomical study of nasal deformities and the
consequences of the primary procedures of cheiloplasty or cheilorhinoplasty, the
authors review all of the most satisfactory technical aspects of secondary
proposed in the literature. Five clinical cases illustrate the therapeutic
strategy and the results.
PMID- 9768068
TI - [Reconstruction of the mouth floor using a musculo-mucosal buccinator flap
supplied by facial vessels. Report of ten cases].
AB - The buccinator muscle is a wide, flat quadrangular muscle. Its medial surface is
covered by the oral mucosa. It receives its arterial blood supply from two main
arteries: the facial and buccal arteries. A musculo-mucosal flap can be raised on
the facial artery with or without the facial vein. In the case of absence of the
facial vein, venous drainage is possible into the peri-arterial loose areolar
tissue. A nasolabial skin incision facilitates facial artery identification and
simplifies flap dissection in the loose areolar plane, superficial to the facial
artery. The mean dimensions of the flap are 3.5 cm in width and 7 cm in length.
The flap extends from the superior buccal sulcus to the inferior alveolar ridge.
Its rotation enables reconstruction of the anterior and lateral floor of the
mouth. The donor site is closed in two layers. The authors present a series of
ten patients reconstructed with this flap after excision of a squamous cell
carcinoma of the floor of the mouth. The results are excellent with perfect
tongue function and no esthetic sequelae. The facial artery should be preserved
during neck dissection, and the ipsilateral mandibular molar teeth must be
extracted. Its simplicity and reliability makes this flap a useful alternative in
floor of mouth reconstruction.
PMID- 9768069
TI - [Eponychial flap].
AB - The author describes an original and new method to lengthen the fingernail plate
in distal digital amputation. After digital amputation, the loss of substance
concerns the pulp tissue and fingernail apparatus. Generally, most palmar falp
techniques can restore functional and aesthetic pulp. The fingernail defect is
obviously not tolerated by the patient and needs to be corrected. The eponychial
flap is a backward cutaneous translation flap. This flap lengthens the nail plate
and restores normal dimensions of the nail apparatus. Two clinical cases are
reported. This technique should be reserved for reconstruction of stage I and II
distal digital amputations.
PMID- 9768071
TI - [Combined Latissimus dorsi and Serratus anterior reverse flow pedicle flap.
Report of a clinical case].
AB - The authors report a new local combined flap involving the distally based
Latissimus dorsi muscle pedicled on the lumber perforating arteries and prolonged
by the last three digitations of the Serratus anterior muscle supplied by the
thoracic branch of the thoraco-dorsal artery. This artifice, never previously
described, increased the bulk and arc of rotation of the dorsalis flap. It was
thus possible to cover a wide defect on the posterior aspect of the sacro-iliac
region in a patient previously operated for a highly malignant histiocytofibroma.
The anatomic considerations, harvesting technique and advantages and drawbacks of
this flap are discussed.
PMID- 9768070
TI - ["Saphenous vascular loop" technique in the treatment of lower limb defects.
Report of five cases].
AB - Five patients with high energy trauma of the lower limb with tissue defect
located in the knee or the proximal third of the leg underwent reconstruction
with a free latissimus dorsi flap. This flap was connected to a vascular
saphenous loop which initially creates an arterioveous shunt between proximal
femoral vessels. This was performed in a single operation with two teams of
surgeons. This technique was chosen because a healthy recipient pedicle was not
available in the vicinity of the defect. Application of vein grafts is not the
usual procedure but there are situations in which it becomes necessary. Our aim
in this paper is to discuss these situations, to describe the technique used in
our Hospital and to analyze the advantages and disadvantages of a one or two
stage operation.
PMID- 9768072
TI - [Aplasia of the skull without scalp anomalies. A case report].
AB - The authors report an extremely rare case of cranio-facial anomaly, which, to our
knowledge has previously been reported only once (1993, Chakraborty and al.).
This male infant presented with a giant congenital bone defect of the skull in
the vertex region (10 x 20 cm) with no scalp deficiency. Minimal turricephaly and
moderate telorbitism were associated with minor limb anomalies, but psychometric
assessment appeared normal. Non-surgical follow-up was initially decided, but
spontaneous reossification was so moderate that skull reconstruction was decided
at 28 months of age, because of traumatological risks. A full-size resin cephalic
skeletal reconstruction was obtained by 3D computerized tomography utilizing
stereolithography techniques. A titanium plate was customized on the resin model
for ideal adaptation to the convex skull defect (8 x 16 cm). Surgery was simply
performed, consisting of preliminary undermining between the dura mater and
scalp, and screwing of the custom titanium plate. The initial follow-up was
uneventful.
PMID- 9768073
TI - [Rare local complication of breast augmentation].
PMID- 9768074
TI - [L-shaped mammoplasty incision with a predefined plan. 80 cases].
PMID- 9768075
TI - [Gunshot injuries and their reconstruction. What is new in 1998?].
PMID- 9768076
TI - [The dynamics of projectile wounding. Concepts in ballistic injuries].
AB - Analysis of the structure and terminal ballistic behavior of bullets provides a
better understanding of their wounding power. The studies of ballistics
specialists serve as a base. The concept of "scientific shot" remains an
intellectual approach to a random phenomenon. Wound ballistic studies examine the
behavior of projectiles in vivo or in a simulation medium. War events, in which
projectiles do not meet requirements of international conventions, sport or
hunting accidents, urban violence may confront the surgeon with various types of
ballistic pathologies. The appropriate saying of Lindsey that the surgeons has to
treat a wound and not a weapon should not justify etiologic ignorance.
PMID- 9768077
TI - [Ballistic data for plastic surgeons].
AB - After a brief review of portable firearms or small caliber guns, the authors
discuss various concepts concerning wound ballistics. Kinetic energy plays an
important part in the damaging action of bullets, while the concepts of "shock
wave" and "stopping power" have been supereded by the definition of wound
profiles. These profiles are characteristic of each bullet. Clinically, they take
the form of a temporary cavitation zone and a permanent cavity. The reaction of
tissues crossed by the bullet largely depend on the elasticity of these tissues
and the presence of bone. The concept of high velocity bullets should be
abandoned. The phenomenon of cavitation alone and its dramatic clinical
consequences should be taken into account and must guide the therapeutic
approach.
PMID- 9768078
TI - [Gunshot injuries of the face. Clinical observations in 21 cases].
AB - The authors report their experience of facial ballistic trauma based on a series
of twenty one homogeneous cases. After a review of the aetiopathogenesis, the
characteristics of facial shocks by missiles of fire arms are described, with
particular emphasis on specific wounds encountered in the head and neck. Two
classifications are suggested: on based on the main clinical features and the
other based on the various types of bullets organized according to wound profiles
and modern ballistics. This new ballistic classification is related to the
clinical features. Although a better approach to ballistics and wound profiles
helps to guide the clinical assessment, the medical and surgical treatments are
based on same principles and approaches in war surgery and in civilian practice.
PMID- 9768079
TI - [Gunshot injuries of the face. Analysis of 165 cases and reevaluation of the
primary treatment].
AB - Our large experience of shotgun injuries to the face emphasizes the need for a
reappraisal of primary treatment for this poorly documented topic. The medical
records of 165 patients, treated at our institution between january 1st, 1982 and
december, 31st 1996 for such an injury, were reviewed. Almost all cases were
exclusively self-inflicted lesions. The guns were mainly twelve-gauge and
occasionally 16 or 20-gauge. Close range wounds in an heterogeneous area--soft
tissue, mandible, muscles of the tongue and floor of the mouth, oral and nasal
cavities, maxilla and paranasal sinuses--caused massive damage. A topographic
classification based on the soft-tissue and bone loss is reported. After initial
management (including securing the airway and control of bleeding), conservative
debridement of all devitalized tissues and stabilization of the fractures were
performed. As soon as possible, bone and soft tissue reconstruction was
undertaken using local or distant flaps. However, immediate definitive
reconstructive procedures were scarcely [corrected] used and only in particular
cases. We believe that a carefully planned reconstruction schedule is required to
achieve satisfactory appearance and function.
PMID- 9768080
TI - [Mandibular reconstruction of gunshot wounds by progressive bone distraction.
Report of five cases].
AB - Five adult patients with gunshot wound defect underwent bilateral mandibular
lengthening by an extraoral device. All patients presented with interrupting
mandibular defect of 50 to 100 mm. Distraction of bone fragments led to
mandibular reconstruction without bone grafting and simultaneous expansion of
soft tissues, avoiding free or pedicled myocutaneous flaps for soft tissue
reconstruction of the lower third of the face. Mandibular distraction also
recreated the alveolar ridge with its attached mucosa which is equivalent to the
gingiva. It can be used for dental rehabilitation by osseointegrated implants.
Avoiding the morbidity and functional problems of classical flaps, mandibular
distraction accelerates facial reconstruction, and social reinsertion of these
patients.
PMID- 9768081
TI - [Microsurgery and ballistic traumatology of the face].
AB - The use of free flaps to fill and repair facial defects due to suicidal gunshot
wounds has considerably extended and refined the possibilities available to
reconstructive surgeon. The objective is no longer to close the defect at any
cost, or "fill a hole", but to replace missing tissue by an identical tissue,
able to restore an identical cosmetic appearance, support equivalent constraints,
and restore analogous function. Retrospective analysis of 56 cases of large
facial defects due to gunshot wounds revealed a total of 66 free flaps for 32
cases. The vascular quality of the flaps allowed better integration in a
sometimes hostile recipient site and markedly reduced the treatment time.
Although the objective results obtained in the treatment of these severe defects
remain poor, the first-line use of these multiple flaps, exclusively reserved for
deep repair, as the basis for reconstruction, has modified our behaviour. A real
medium-term treatment strategy, based on a decision flow-chart, can be proposed
which, despite several inevitable failures, leaves less room for improvisation
and piecemeal surgery. Free flaps are only the hidden part of the reconstruction,
as surface cover uses local flaps and other conventional reconstructive surgery
techniques. However, this humble, hidden role is nevertheless fundamental, in the
strict sense of the term, and guides the general approach to this surgery.
PMID- 9768082
TI - [Gunshot wounds of the extremities in civilian practice. Therapeutic approach in
five cases with diaphyseal bone involvement].
AB - The authors analyse 5 cases of gunshot wounds involving limbs with a diaphyseal
fracture of the radius and ulna: 3 of the cases concern the radius and ulna and
the remaining 2 involve the tibial bone. These wounds were encountered in
civilian practice (3 rixes, 2 gun-shot injuries). In all of the cases, the
emergency treatment consisted of extensive debridment, bone fixation by
intramedullary nailing in most cases, cancellous iliac bone grafting in 2 cases,
cover with a Latissimus dorsi free flap in 1 case. In all of the cases,
development was free of infections bone union time was 3 to 12 months; last
functional results were satisfactory.
PMID- 9768083
TI - [The life of Maurice Virenque (1888-1946). From "Gueules Cassees" to
cervicofacial facelift].
AB - When going through the biography and bibliography of M. Virenque, one realizes
that he was an outstanding maxillo-facial surgeon, who developed his knowledge
mainly during the two world wars 1914-1918 and 1939-1945 and gave exceptional
care to soldiers with severe face and skull injuries, the so-called "Gueules
Cassees". Nevertheless, he did not disregard the importance of aesthetic surgery
born between the two wars. Due to his large experience in maxillo-facial surgery
and his broad knowledge of the anatomy of the face, he occupies a special place
among the forerunners of facelifts by stressing on the importance of plication of
the deep aponeurotic layers of the face, thus allowing the elaboration of a
modified approach to the problems of the aging face.
PMID- 9768084
TI - [Macroreimplantation of the upper limb. Results in 24 cases].
AB - The authors present a retrospective study of 24 cases of macroreimplantations of
the upper limb operated between 1985 and 1995. The upper limb survival rate was
54%. The prognosis was better for sections distal to the middle third of the
forearm. The cause of early failure was arterial thrombosis and that of later
failures was muscle necrosis, responsible for infections and venous thromboses.
The functional results are analysed as a function of the type of amputation.
Sections outside of muscle zones or with nervous continuity have a more
favourable prognosis. 33% of reimplantations obtained a good or excellent result
according to Chen's criteria. Poor functional results are nevertheless associated
with a number of positive points: protection sensitivity, useful elbow,
psychological satisfaction of limb preservation.
PMID- 9768085
TI - [Role of emergency reconstruction of fingers by the "reposition-flap" technique.
Report of eight cases].
AB - Following replantation failure, fingertip reconstruction was performed as an
emergency "reposition-flap" procedure in seven patients (eight fingers). This
technique was intended for amputations distal to the DIP joint in long fingers,
and IP joint in the thumb. Pulp was excised on the amputated segment, and the
remaining bone and nail bed were reattached to the proximal stump with Kirschner
wires. Pulp was reconstructed with a local advancement and sensitive flap.
Trophicity and nail regrowth as well as mobility and strength were satisfactory
in five cases. MRI examination showed revascularization of the distal bone
fragment in four cases. This procedure is an alternative to amputation after
replantation failure when patients do not accept finger shortening. The more
distal the amputation, the better is the result.
PMID- 9768086
TI - [Posterior thoracic reconstruction with latissimus dorsi flap after partial
amputation of the latissimus dorsi muscle for sarcoma of the back. Report of four
cases].
AB - Malignant fibrous histiocytomas (MFH) arising from the subcutaneous tissues of
the posterior thoracic wall require wide, but usually non-transfixing, resection
to ensure adequate resection margins, the only way to reduce the local recurrent
rate. Due to its size and position, the Latissimus dorsi muscle usually requires
partial amputation. However, its vascular anatomy allows it to be used as a
musculocutaneous flap of the residual muscle to fill the defects created. Four
clinical cases are reported. This technique reduces the complication rate and
simplifies the postoperative course.
PMID- 9768087
TI - [Under the epidermis, the dermis, or how to interpret skin cultures?].
AB - After a brief review of the three basic principles of reconstruction of the skin
(structure, antigenicity and function), the author presents the various skin
culture techniques, tissue by tissue. He explains the main methods of
reconstruction of natural or artificial dermal tissue and epidermal structures,
and finally the in vitro simultaneous reconstruction of both tissues, dermis and
epidermis; only this last technique can really be called "skin culture".
PMID- 9768088
TI - [Intraluminal absorbable device to assist in vascular microanastomosis.
Experimental study on 20 rat aortas].
AB - The subject of this experimental study is a cylindrical device, with a gauge
adjusted to the vessel lumen, which disintegrates in a few minutes. The goal of
this device is to increase the reliability of vascular microanastomosis. This
study was designed to assess the efficacy and drawbacks of the device. The device
is a cylindrical sugar stick, 5 mm long and with a gauge of 1 mm. Ten Wistar rats
underwent a standard end-to-end aortic anastomosis with interrupted sutures and
ten underwent the same anastomosis with the device placed in the lumen of the
proximal and distal vessel. The same surgeon performed all anastomoses. Clamp
application time was recorded and anastomotic patency was tested in each case;
the vessels were also examined histologically. The clamp application time was
significantly lower (p < 0.01), and the patency rate significantly higher (p <
0.01) in the group in which the device was used. There was no histologic sign of
intima injury in either group. This very simple device facilitates
microanastomosis. It reduces the ischemia time and increases the reliability of
the anastomosis, avoiding transfixing sutures. These results suggest that
clinical trials are warranted.
PMID- 9768089
TI - [Vascular microanastomosis by eversion and stapling using VCS forceps.
Presentation of the technique and experimental evaluation of its reliability].
AB - With the objective of further improving the reliability of microvascular
anastomoses, several different procedures are now available to microsurgeons,
including eversion-stapling by VCS forceps. The authors start by presenting the
technique, emphasizing the need for specific instruments and compliance with
certain principles determining the success of these anastomoses. In the context
of an experimental protocol in the pig, on vessels measuring an average of 2.5 mm
in diameter, 80 anastomoses were performed by VCS stapling-eversion and studied
clinically, histologically and ultrastructurally, comparing the results to those
of conventional anastomoses by approximation-suture with needle and suture. In
light of the results, eversion-stapling anastomoses appear to be more reliable
due to the absence of intraluminal foreign body, permanent endothelial continuity
and effective re-endothelialisation before day 7.
PMID- 9768090
TI - [VCS microclip anastomosis on blood vessels of less than 2 millimeters in
diameter. Preliminary experimental study in the rat].
AB - The aim of this work was to study the possibilities and limits of the vascular
microanastomoses with VCS microclips. VCS Microclips are a new mechanical
anastomotic device, allowing a single operator to perform anastomoses without
microsutures. The two arcuate limbs of the titanium microclips do not penetrate
the vascular intima. The microclip anastomosis technique is based on symmetric
eversion of the vessel walls, facilitated by everting forceps. We studied the
medium and small Autosuture VCS microclips on different vessels ranging from 0.3
to 2 millimeters in diameter: aorta, carotid artery, femoral artery and femoral
vein. Thirty nine end-to-end or end-to-side anastomoses were performed on Wistar
rats. These anastomoses were performed by a single operator without the use of
sutures. Patency was studied by the "empty and refill" test immediately and at
two months. Histologic analysis of the anastomosis was performed at two months
(hematein-eosin and orcein stains on longitudinal sections). Four out of thirty
nine anastomoses were occluded during the 15 minutes following clamp release.
Failure was always due to a technical error and occurred during the first trials.
The thirty five other anastomoses were patent immediately and at two months post
operatively, except for the by-pass which was not viable. These anastomoses were
still patent 30 minutes post-operatively. Light microscopy analysis confirmed
that the microclip extremities did not penetrate the lumen, although the internal
media was usually very thin at the level of the microclip jaws, especially for
the smallest vessels. For vessels larger than 1 mm in diameter, the microclip
extremities were usually outside the internal elastic lamina. No anastomotic
aneurysm was found. Vascular healing was comparable with microsutures at 2
months. Microvascular anastomoses performed with microclips have numerous
advantages, compared to usual microsutures: they are two to three times quicker,
they can be performed step by step without turning the clamp and they can be
performed with the right or left hand. There is theoretically no thrombogenic
risk. The drawbacks are the need for complementary training and the cost of
microclips which is five to six times that of sutures. End-to-side anastomoses of
small vessels are more difficult than end-to-end anastomoses. The recipient
vessels must be larger than 1.5 mm in diameter, otherwise the anastomosis may
become stenosed. Microclips are especially useful to save time, i.e. for multiple
anastomoses and for anastomoses of vessels larger than 1 millimeter in diameter.
Some modifications of the material could allow vascular or hollow organ
anastomoses with endoscopic assistance.
PMID- 9768092
TI - [Skin problems in severe retraction stiffness of the hand and fingers. Role of
the so called "castle" flap].
AB - Skin retraction is a commonly observed complication of severe joint stiffness in
the hand. After freeing the joint, this raises the problem of closing the skin
without tension to avoid necrosis, disunion or pain during early rehabilitation
and splinting. We have used a simple rotation flap for PIP extension (and
hyperextension) stiffness and a "castle" flap for PIP flexion retraction and for
both extension and flexion stiffness of the MPJ. It consists in withdrawing the
skin (dorsal or palmar) of the phalanx distal to the freed joint. We have used
this flap in 13 clinical cases of severe stiffness and it allowed wide access to
all structures involved and facilitated early post-operative mobilization.
PMID- 9768091
TI - [Bone substitute with growth factor. Preliminary clinical cases for cranio- and
maxillo-facial indications].
AB - Several biological materials have been analyzed in combination with osteo
inductive growths factors to determine whether such a system can replace bone
grafting in surgical practice. Efforts have been aimed at the discovery of the
best carriers and delivery systems. We present the results of the surgical
treatment of 11 cranio-maxillo-facial defects in 9 patients using a combination
of natural coral skeleton (NCS in blocks or granules), human fibrin glue and
transforming growth factor beta-1 (TGF-beta 1) as a composite bone substitute.
Three patients were initially excluded because of early extrusion of the
materials due to a technical error. Clinical and radiological evaluation was
performed in all cases, with the patient acting as his own control. Clinical
firmness and radiological mineralization occurred in three quarters of cases. New
bone formation was confirmed histologically in two of these patients. Clinically
the initial results remained stable over a three years follow-up with staged
surgical procedures performed on a number of patients. None of the patients
suffered any detrimental effect from implantation of the bone substitute.
Although the numbers in these series are limited, the association of TGF-beta 1,
human fibrin glue and NCS represented an interesting step, although the clinical
results could be improved. Important factors in the success of this technique
appeared to be stabilisation of the biological materials, quality and asepsis of
the surrounding tissue and the dose of growth factor.
PMID- 9768093
TI - [Use of gracilis musculocutaneous flap in tissue loss caused by Fournier's
gangrene. Apropos of 4 cases].
AB - The gracilis myo-cutaneous flap was used in 4 patients to cover soft tissue
defects of the perineal, scrotal, penile and inguinal regions after Fournier's
gangrene. This is a simple technique, which allows a simultaneous reconstruction
of the perineoscrotal region. Very satisfactory esthetic and functional results
were obtained in the recipient and donor sites.
PMID- 9768094
TI - [Abdominoplasty with dissociated intraparietal liposuction. Technical note].
AB - Liposuction has greatly contributed to the improvement of the aesthetic result of
abdominoplasties. However, one should consider the high rate of seroma when
liposuction is performed via an inferior approach during abdominoplasty. The
authors present a new approach to achieve complete liposuction of the abdominal
wall during conventional abdominoplasty. This approach is carried out via
submammary incision after previous undermining of the abdominal wall. A permanent
assessment of the thickness of the wall allows the liposuction to stay strictly
in fat tissue. Finally, there is a total independence between liposuction and the
undermining procedure which allows minimization of the postoperative seroma. This
technic seems particularly useful in a context of extensive abdominal adipose
with flaccidity of the abdominal wall, requiring extensive undermining. Thanks to
this procedure, the authors have performed a one-stage operation in many cases in
which two operations would necessary previously have been.
PMID- 9768095
TI - [Mammaplasty with an L-shaped scar and a pre-established design. Apropos of 80
cases].
AB - Over recent years, surgeons have tried to reduce the reduction mammaplasty scar.
In this context, we use a surgical technique described by J.P. Chavoin,
privileging "the remaining breast". Three advantages of this surgical method are
derived from its technical choices: a superior dermal pedicle for preservation of
the areolar nipple complex, preoperative drawing and finally a short incision
with an inverted L scar. A retrospective study of 80 patients with 27 months of
follow-up defines the advantages and disadvantages of this technique. Discomfort,
indications, quality of results are evaluated with charts. Preoperative drawing
and technique are described. This study shows this to be a reliable technique
with good and constant results. Lastly, its indication is described in comparison
with other techniques designed to achieve. Its preferential indication is
moderately severe hypertrophy (500 g), which represents the majority of patients
consulting us, but it can also be used in severe hypertrophy or even
gigantomastia. Reduction of asymmetry also constitutes a good indication,
facilitated by rigorous skin drawing based on precise anatomical landmarks. In
addition to its broad indications, its advantages are marked vascular safety,
rapid execution, constant results, while preserving the median part of the thorax
from any scars.
PMID- 9768096
TI - [Lipoid proteinosis: importance of dermabrasion. Apropos of a case].
AB - The authors report case of lipoid proteinosis. This is an autosomal recessive
genetic disease involving the skin and mucous membranes. Skin lesions have a
granular appearance, with infiltration and wrinkling of the skin, especially on
the face. The authors show the success of dermabrasion on skin lesions on the
face of a 21-year-old girl displaying typical symptoms of lipoid proteinosis.
PMID- 9768098
TI - [Voyage to Catalonia].
PMID- 9768097
TI - [What is the cost of excision-suture of a skin lesion under local anesthesia? 2
month prospective evaluation in a public sector hospital].
AB - The purpose of this study was to assess the cost of a minimal surgical operation:
skin surgery under local anesthesia in the outpatients department. A two-month
prospective study was carried out on 149 operations, with a mean duration of 33
minutes. The mean cost of the operation was 434 FF. Although this study is very
specific and its results cannot be generalized, it gives a method and an order of
magnitude. It shows that it is difficult to save money without decreasing the
quality of the operation. The price list of the French national health care
system, and the price of the surgeon himself are discussed.
PMID- 9768099
TI - [Update mid-term review of the pedicular extension in reverse YV flow. Review of
a 7-year experience].
AB - Since 1990, the authors use a surgical procedure called reverse flow YV pedicle
extension to transfer a flap distally to its donor site. Their clinical
experience, based on of 8 different applications and more than 80 clinical cases,
demonstrates the reliability of the procedure. Nevertheless, the latissimus dorsi
transfer, based on scapular vessels, must be an exceptional indication due to the
need to achieve a venous microanastomosis. Moreover, the "extreme lateral arm
flap" is considered to require a precise preoperative anatomical assessment
because of the variants of the pedicle bifurcation. The authors are convinced
that further applications will extend their experience of this procedure.
PMID- 9768100
TI - [The use of pedicular flap from the squared pronator muscle in the prevention and
treatment of neuritis. Report of 8 cases].
AB - The distal third of the forearm is a tendinous area, in which nerves could be
irritated by surrounding skin scars or synovitis. In this area, a distally or
proximally based pronator quadratus muscle flap could be used to wrap around the
median or superficial branch of the radial nerve. Such flaps have been used
successfully in eight cases, four cases of chronic neuritis, 2 cases of wrapping
a median nerve graft and 2 cases of nerve coverage following trauma. All patients
obtained pain relief with no alteration of finger movements.
PMID- 9768101
TI - [Treatment of the sequelae of enucleation by septal chondro-mucosal composite
graft. Report of 21 cases].
AB - Enucleation frequently and progressively causes an enophtalmus and atrophia of
the inferior eyelid, thereby leading to a height deficiency. Buccal mucous grafts
give rise to phenomena such as secondary retraction. This may have complex and
painful post-operative outcomes. However, when a septal chondromucous graft is
performed, the height in the inferior palpebral part becomes more aesthetic, more
retentive and quickly allows the wearing of a more voluminous prosthesis. Thus,
the notinable enophtalmus can be corrected and the aesthetic quality of the
looking is substantially restored. The authors report this surgical procedure and
the results obtained with 21 patients which appear to be particularly promising.
PMID- 9768102
TI - [Fasciitis following face lift].
AB - Facial fasciitis or non infectious facial retractions are rare and surprising
events after a facelift performed at any age. The signs are firm retraction
located on one or both sides of the face or neck. They differ from salivary
fistula, localised oedema, and limited hematoma, which may be the initial factor
responsible for this curious outcome. We found a particular psychological status
in these patients, who are often fragile and depressed and who obtain a secondary
gain from this impaired status. The treatment of facial retraction (facial
fasciitis is non surgical: we recommend local massage, patience and psychological
help for quite a long time (6 months-one year). The outcome is spontaneously
favorable, unless the patient automanipulates. A psychosomatic link must be
considered. This transient facial retraction may correspond to some forms of hand
retraction (such as Dupuytren's disease with spontaneous healing) or some
thoracic retractions after insertion of mammary prosthesis. Facial fasciitis is a
rare complication in our practice (1.4% of all patients) but must be recognized.
PMID- 9768103
TI - [Effect of irradiation fields on the results of breast reconstruction with skin
expansion after radiotherapy].
AB - Deferred prosthetic breast reconstruction after skin expansion is considered to
be difficult after radiotherapy. The authors report a series of 14 cases of
reconstruction after radiotherapy, compared with 6 cases of reconstruction
without radiotherapy. They reported a similar quality of results after
radiotherapy not including irradiation of the chest wall and in the absence of
radiotherapy (p = 0.742). On the other hand, a significant deterioration of the
results was observed when radiotherapy included chest wall irradiation (p =
0.0015). Finally, no direct correlation was observed between the macroscopic
appearance of the skin and presence or absence of a history of irradiation of the
chest wall. They conclude that the indications for reconstruction by tissue
expansion after radiotherapy must be based more on the irradiation protocol than
on the macroscopic appearance of the skin.
PMID- 9768104
TI - [Surgical treatment of pterygium colli. A case report and review of the
literature].
AB - The authors describe the characteristics of the pterygium colli, symptom of
several congenital diseases. Based on a review of the literature, they report the
surgical techniques available to correct this deformity. This malformation may be
due to asymmetrical development, inducing a vertical skin defect, which requires
correction. The so-called posterior techniques are recommended; they allow good
morphologic improvement (restoration of neck outline and natural posterior
hairline), with minimal scarring. One case treated by a posterior technique is
reported. Laterocervical skin expansion has been used by some authors, and seems
to allow correction of these cutaneous anomalies, with a better morphologic and
cosmetic result.
PMID- 9768105
TI - [The use of the internal tissue expansion procedure in reconstructive surgery.
Preliminary study and report of 2 cases].
AB - The Frechet extender, initially proposed and successfully used in scalp
reductions, can have many other indications in reconstructive surgery. This paper
describes the preliminary results obtained after using this internal tissue
extender in the treatment of a limb burn scar and a congenital giant naevus of
the back. After a 3 month follow-up, these results are excellent. This procedure
gives good results especially when there is a bony support underneath the skin to
be treated.
PMID- 9768106
TI - [Free fibula transplant and practical approach in the absence of posterior tibial
artery. A report of 2 cases].
AB - The authors report two well documented cases of absent posterior tibial artery in
patients undergoing free fibula transplant. The first patient was a 50-year-old
woman treated by pelvimandibulectomy for squamous cell carcinoma, leaving a
defect of the floor of the mouth. The second case was an 11-year-old child with
Ewing sarcoma of the femoral metaphysis, in whom femoral reconstruction was
performed by vascularized free fibula transplant. Based on these two cases, the
authors describe their diagnostic and therapeutic approach designed to avoid
risks associated with this anatomical variant. Absence of the posterior tibial
artery can be confirmed by arteriography and duplex ultrasound. The authors
propose duplex ultrasound as first-line investigation as this safe, noninvasive
examination provides sufficient information in the majority of cases at a lower
cost. In parallel, the various anatomical variants affecting the origin of leg
arteries from the popliteal artery are classified into seven groups based on a
phylogenetic and embryological study.
PMID- 9768107
TI - [Syringomatous tumor of the nipple. A case report and review of the literature].
AB - The authors report a case of syringomatous tumor of the nipple in a 35-year-old
woman, discovered incidentally during investigation of dysmenorrhea. After
limited resection-biopsy of a cystic nipple tumor, histological results indicated
the need for a partial central mastectomy with areola and nipple amputation.
Although this tumor is classified as an adenoma, considered to be a benign
lesion, syringomatous adenoma of the nipple is a potentially locally aggressive
tumor, at risk of local recurrence and deep invasion of the mammary gland. This
is a rare tumor (only 18 cases have been reported in the literature), and the
histological diagnosis can be difficult, with possible confusion with a nipple
duct adenoma, or tubular carcinoma.
PMID- 9768110
TI - [Photography and plastic surgery. From scientific honesty in general...to
photographic touching up in particular].
PMID- 9768108
TI - [Erosive adenomatosis of the nipple. Report of 2 cases].
AB - Superficial papillary adenomatosis of the nipple is a benign tumor of the ductal
epithelium that clinically resembles Paget's disease. Unilateral serous, bloody,
or serosanguinous discharge with crusting is most commonly present. Symptoms
include tenderness or pruritus. Histologically, the tumor is characterized by
proliferating ductal structures lined by a double layer of columnar epithelium.
The lesions are focally eroded. Keratin cysts and apical intraluminal projections
are commonly found. The original description was reported in 1954 in the english
language literature. Just a few cases have been reported in the french
literature. These cases are reviewed and two classic examples are reported; their
therapeutic options are discussed.
PMID- 9768111
TI - [Genetics of craniofacial malformations].
AB - The most frequent craniofaciosynostoses, Crouzon, Apert and Pfeiffer syndromes,
are due to mutations of genes coding for FGF growth factor receptors (FGFR). The
Twist gene has been recently implicated in Saethre-Chotzen syndrome. The current
confusion concerning phenotypegenotype correlation is starting to be clarified by
the increasing number of cases in which the mutations have been identified and
the clinical classification will need to be revised in the light of the results
of molecular genetics.
PMID- 9768112
TI - [Modern imaging of craniofacial malformations].
AB - Due to progress in the field of medical imaging of craniofacial malformations,
the place of these investigations in the assessment of these abnormalities needs
to be revised. 3D CT scan currently remains the fundamental element of the
assessment by providing a truly anatomical dissection of each bone. In the field
of craniostenoses, the study of the base of the skull has allowed a new
assessment of lesions of skull base and craniofacial sutures and the resulting
skeletal deformities: they provide restrospective justification for an extensive
approach to the surgery of this group of malformations and a basis for reflection
concerning extension to direct skull base surgery. Craniofacial clefts constitute
a heterogeneous groupe of anomalies in which Tessier's concepts have allowed a
methodical approach. 3D CT allows better definition of certain subgroups of
malformations within this group (midfacial clefts) and provides a clearer
understanding of the skeletal defects of maxillary clefts, especially in the
laterofacial region. This imaging is currently undergoing rapid development.
Improvement of 3D CT scanning techniques (direct 3D image acquisition,
improvement of the images obtained), development and combination of 3D MRI, after
being superimposed onto the skeletal image, will allow total dissection of the
malformation. Development of 3D cephalometric analysis techniques and growth
analysis software will allow really predictive "image-assisted surgery". Finally,
antenatal imaging (B-mode and 3D ultrasonography) makes a considerable
contribution to this field of anomalies by allowing the diagnosis of serious or
severely disabling anomalies and by elucidating the antenatal development of
certain anomalies (especially craniostenoses) and their consequences.
PMID- 9768113
TI - [Unusual facial clefts].
AB - After briefly review facial morphogenesis, the authors define facial clefts,
distinguishing primary clefts, secondary clefts, and residual clefts. They
discuss the uncertainties surrounding the embryology and clinical features of
palpebral colobomas. The various pathogenetic concepts are analysed: amniotic
hypothesis, vascular hypothesis, fusion defect. The various classifications of
rare facial clefts are reviewed, with particular emphasis on Tessier's
classification and the so-called Milan classification. The general principles of
surgical treatment are described together with the various skeletal and soft
tissues procedures.
PMID- 9768114
TI - [Craniosynostosis and faciocraniosynostosis].
AB - The authors present a review of the aetiopathogenesis and treatment, based on a
series of 1321 craniostenoses operated by the Enfants Malades team. After briefly
reviewing the embryology of craniofacial growth, the authors describe the
morphological classification of craniostenoses and their morphological and
functional consequences. The main neurosurgical problems related to craniofacial
surgery are described. The surgical techniques currently used by the unit are
described for each type of craniostenosis, according to age: H or flap
transposition craniectomies for scaphocephaly, unilateral advancement of a
bilateral head-band for plagiocephaly, anterior transposition for oxycephaly, and
fronto-orbital adbancement for brachycephaly. The results are presented with a
follow-up of several years. The principles of one-stage or two-stage surgical
treatment for the main types of faciocraniostenosis are recalled: initial fronto
orbital advancement then secondary treatment of maxillary recession. The
prospects of one-stage combined treatment with early maxillary distraction are
proposed. Surgical indications are described. The complications, morbidity and
mortality are indicated for the series. It must be remembered that craniostenosis
surgery is a form of plastic surgery with neurosurgical complications. To obtain
optimal results with the lowest risk, craniofacial must be performed by
multidisciplinary teams in specialized centres.
PMID- 9768115
TI - [Maxillo-mandibular ++disharmonies].
AB - The maxilla and mandible give the face its proportions and equilibrium, while
remaining indissociable from the skull. The harmony of these structures is
established according to two planes of reference: the base of the skull in a
relationship of cranio-facial interdependence, the dental arch making the
occlusal relationship a decisive factor in the concept of facial equilibrium.
This occlusal obligation, criterion of normality and stability, confers all of
the originality of orthognatic surgery, which must also take into account the
periods of cranio-facial growth and oro-facial functions. The authors describe
the modern concept of this surgery, the essential place of orthodontic
preparation, and technical innovations such as computer-assisted simulation.
PMID- 9768116
TI - [The posterior cranium and its dysmorphisms].
AB - The deformation of the posterior part of the skull (occipito-vertebral region)
induced directly, occurs in numerous pathological situations. Its significance is
frequently overlooked. Lesions of the cranial content, alterations of the
lambdoid suture or other premature synostosis, abnormal constraint related to
posture or to muscular activity can modify the posterior curvature of the skull,
generally flattening it. The authors propose a classification based on three
points: intracranial pathology, bone pathology and extrinsic pathology.
Concerning intracranial pathology, alterations of the brain or CSF fluid can
induce either insufficient (microencephaly) or excessive (hydrocephalus, Dandy
Walker or Arnold Chiari malformations) expansion. Concerning bone pathology,
sagittal synostosis (scaphocephaly) induces a bulging and coronal synostosis a
flatness of the posterior skull. Bilateral premature lambdoid synostosis
(pachycephaly) produces total flatness of the back of the skull. Concerning
extrinsic pathology, dysmorphism is often asymmetrical and results from
extracranial mechanical application dysfunction such as inborn torticollis,
cervical spine pathology (Klippel-Feil syndrome), or prolonged decubitus during
the first year of life. The different surgical procedures are described and the
authors describe a personal technique for correcting this dysmorphism: the turned
biparietal flap transposition. The back of the skull is remodelled (either
asymmetrical or bilateral flatness), and patients with no need for a helmet can
lie on their backs immediately after the operation.
PMID- 9768117
TI - [Surgical treatment of micro-ophthalmic syndromes].
AB - The complex embryology of the oculo-orbito-palpebral region is responsible for a
number of heterogeneous clinicopathological situations, associating variable
proportions of the three components of the malformation: micro-anophthalmia,
microblepharism, micro-orbitism. Application of the double principle of skin
expansion for the eyelids and distraction of the callus for the orbit, as early
as possible (first year of life), is possible by means of a device which consists
of a combination of an intraorbital expansion balloon, an antireflux valve to
avoid effective pressure losses in the balloon, and an injection site for
progressive filling of the expansion balloon. The response to these treatments is
excellent for cases of simple microphthalmia and micro-orbitism; in complex
craniofacial malformations, it generally only partially resolves the problem, but
provides a precious complement to the quality of the final repair.
PMID- 9768118
TI - [Mandibular distraction].
AB - The authors review the bone lengthening techniques used in orthopaedics, analyse
the application of osteogenesis by surgical distraction of the mandible and
describe the progress in techniques and equipment. The presentation of clinical
cases of mandibular hypoplasia treated by intraoral distraction emphasizes the
value of this new technique, particularly in terms of the morphological results,
which are superior to those obtained by conventional techniques.
PMID- 9768119
TI - [Distraction of the maxilla].
AB - The distraction of the maxilla provides very useful possibilities in young
children with unstable articulation and in infants in order to avoid excessively
radical operations. The principles of the distraction are reviewed. The authors
report 13 clinical cases and complications. The material needs to be perfected,
as numerous incidents are still observed.
PMID- 9768120
TI - [Contribution of microsurgical transfers in filling cranio-facial substantial
losses].
AB - In the series reported in the literature, microsurgical transfers for
craniofacial reconstruction generally concern the face. The authors present a
series of four complex reconstructions of the cranial vault and orbital floor. In
one case, they used a prefabricated radial pedicle flap and, in the other cases,
they used two-stage cover flaps, with satisfactory results.
PMID- 9768121
TI - [The external carotid vein. Historical review of Paul Launay's work].
AB - The authors, one century later, review the anatomical studies conducted by
Launay, a student of Farabeuf, concerning the venous drainage of the face and
neck. These studies were based on the analogy between the arterial system and the
venous drainage of the external carotid territory. After describing the external
carotid vein, the didactic and practical aspects of this study are emphasized.
PMID- 9768122
TI - [Mental prognosis of trigonocephaly and therapeutic implications].
AB - The authors assessed the long-term mental prognosis of trigonocephaly, in a
series of 76 operated cases. Mental prognosis factors were studied, showing that
early cranial release and reconstruction were effective. Final assessment of
mental development was performed on children of school age, and was based on the
development of behavioral disturbances, learning disability, school difficulties,
and intellectual efficiency. Children were graded into 3 groups: no abnormality,
mild abnormalities with normal socialization, major abnormalities; 31.6%
presented disorders. Preoperative C-T scans assessed the severity of the cranial
deformity and identified associated intracranial abnormalities, such as agenesis
of the corpus callosum, dilatation of the subdural spaces, or hydrocephalus.
Associated extracranial malformations, and associated family cases were also
noted. Finally, the quality of the family context was studied. Several
correlations were identified; mental development was correlated with the severity
of frontal stenosis, the age at surgery and the associated extracranial
malformations. Family environment also had a major influence. Intracranial
abnormalities were not correlated with mental development.
PMID- 9768123
TI - [Iatrogenic extravasations of cytotoxic or hyperosmolar aqueous solutions. Value
of surgical emergency by aspiration and lavage].
AB - Iatrogenic extravasations are characterized by their unpredictable course, the
possible repercussions of functional, cosmetic and psychological sequelae, and
the absence of a therapeutic consensus. The authors present the protocol used in
Hopital Saint-Louis, based on a synthesis of current procedures, consisting of
emergency conservative surgical aspiration and lavage, performed in a context of
close collaboration with oncolosits, intensive care physicians and radiologists.
From 1994 to March 1997, fifteen patients were operated following extravasation
during seven chemotherapeutic protocols, three radiographic examinations with
injection of contrast agents and five resuscitation procedures. This simple
protocol, applied systematically, achieved cure without cutaneous or functional
sequelae in all patients. Aspiration-lavage during the first twelve hours
therefore constitutes the treatment of choice of iatrogenic extravasation with
cytotoxic or hyperosmolar aqueous solutions.
PMID- 9768124
TI - [Skin sensitivity before and after reduction mammaplasty. Report of 44 cases].
AB - The main aim of reductive surgery for breast hypertrophy has often been the
aesthetic result without considering on the cutaneous sensitivity. This
retrospective analysis studied the subjective and objective sensitivity after
mammoplasty reduction 44 patients. The preoperative results showed a reduction of
sensitivity directly proportional to the ptosis. After surgery the patients
described an improvement of the sensibility, especially in the case of moderate
resection. This study shows the good restoration of nerve fibers after chronic
stretching due to hypertrophy. Nerve fibres were restored when areolar graft was
used.
PMID- 9768125
TI - [Complex facial nevus in children treated by combination of prosthetic and
deferred natural expansions].
AB - Congenital pigmented naevi of the face in children represent indications for
early excision and the search for the best aesthetic result has led the authors
to prefer the use of skin expansion techniques. The case presented here
illustrates the combined use of two expansion techniques: prosthetic expansion
and natural differed expansion. This procedure gives good cosmetic results at a
moderate overall cost.
PMID- 9768126
TI - [Desmoplastic malignant melanoma of the ear. A case report].
AB - A case of desmoplastic melanoma in a 72-year-old patient is reported. In the
light of this case, the authors review the literature and analyse the therapeutic
implications.
PMID- 9768127
TI - [Lipoma of the superficial lobe of the parotid gland. A case report].
AB - We report the case of a patient with a lipoma of the superficial lobe of the
right parotid gland. Lipomas of the parotid gland are very rare. They are said to
constitute one to two percent of all parotid tumours. Only six cases were found
in the recent literature. Preoperative diagnosis is difficult when the physical
examination reveals a renitent, well-localized and painless mass. However,
magnetic resonance imaging is now the imaging modality of choice to facilitate
the diagnosis, but the diagnosis can only be confirmed by histological
examination of the tumour. We discuss the value of superficial parotidectomy,
while some authors suggest an enucleation of lipomas of the superficial lobe of
parotid.
PMID- 9768128
TI - [Malignant melanoma in a 7-year-old child. A report of a dramatic case].
AB - Malignant melanoma developed on the scalp at the site of a congenital nevus in a
7-year-old girl. At birth, simple observation was proposed, despite the
recognized desirable but non-urgent indication for excision, in order to avoid
subjecting the infant to general anesthesia. At the first sign of a change in the
macroscopic appearance of the nevus, surgical resection was performed, but the
short-term outcome was fatal.... This case focuses our attention on malignant
progression of even small congenital nevi and emphasizes the need for early
preventive and systematic resection even when the patient's age of the patient
requires general anesthesia.
PMID- 9768129
TI - [Hemifacial atrophy. A case report associated with linear scleroderma].
AB - The authors report a case of facial hemiatrophy, secondary to linear scleroderma,
and review the various possible causes of facial hemiatrophy. The various
treatments proposed to correct facial hemiatrophy are described. The advantages
and disadvantages of each technique together with their indications as a function
of the severity of the lesions are then discussed. Free flap currently appears to
be the treatment of choice in severe forms and the main question concerns the
choice of flap. The authors prefer an inverted dermal fat flap because of its
advantages (absence of long-term ptosis, better facial contours) and the absence
of laparotomy.
PMID- 9768130
TI - [Conservative cervico-facial facelift. Concept and preliminary results].
AB - A new cervico-facial facelift is presented, taking into account the cervico
facial cutaneomusculo-aponeurotic unit (CMAU) comprising skin, subcutaneous
adipose tissue, superficial musculo-aponeurotic system and the particular
mechanism of cervico-facial ageing. The undermining, limited to the parotido
masseretic region, is not subcutaneous, but immediately submusculoaponeurotic.
The advantage of this facelift is to replace all of the CMAU over the underlying
musculo-aponeurotic or osteo-periosteal planes, without modifying superficial
relations. The cutaneous detachment preserves the natural appearance of the face
and avoids the classical complications of facelift.
PMID- 9768131
TI - [Indications and results of breast implant replacement with implants pre-filled
with silicone gel].
AB - Based on a series of 74 patients, the authors report their experience of
reoperation on unsatisfactory breast implants by the implant replacement
technique using silicone prefilled implants. In 92 (57.8%) of the 160 cases, the
implant was modified because of a peri-implant capsule, with a satisfactory
aesthetic result after only a single operation. However, this leaves the problem
of repeated surgical operations, especially in the context of Baker stage IV
capsules, which are only partially improved after two to three surgical
operations. A particular surgical revision technique is required in the cases,
while the role of in situ cortivazol is under investigation. This series
comprises two patients with auto-immune disease and dysimmune profiles, not
exarcerbate by secondary surgery. Analysis of this series clearly argues in
favour of reoperation for unsatisfactory breasts implants. Squeezing manoeuvres
appear to be dangerous and useless. Textured implants filled with very cohesive
silicone gel should be maintened in view of the absence of any reported serious
complications.
PMID- 9768132
TI - [Paraffinomas: history, clinical features and treatment. A case report].
AB - One case of paraffinoma is reported on a 60 years old man following injections of
paraffin fourty years ago. The authors recalled with this observation history of
paraffin, clinical aspect and surgical treatment of the paraffinoma.
PMID- 9768133
TI - [Severe cutaneous necrosis after ultrasound lipolysis. Medicolegal aspects and
review].
AB - The authors report the case of a young patient who developed extensive skin
necrosis after ultrasound liposuction of the medial surface of the thigh. These
lesions required excision, split-skin graft and installation of an expansion
prosthesis. The medicolegal aspects of this case are discussed, in particular the
responsibility of the doctor who performed this damaging procedure, from three
points of view: damage, fault, causality. In this case, the damage corresponded
to necrosis which can be due to a chemical, infectious or thermal mechanism. It
is responsible for serious damages due to the number of operations, the length of
hospital stay, immobilization, rehabilitation and the time off work. The
aesthetic damage, the pretium doloris, and the inconvenience are certainly
considerable, but was there fault in this case? Fault by clumsiness if the
equipment was used abnormally; fault by negligence or imprudence when the
equipment was not approved or when the operator was not a qualified physician,
submitting his patient to undue risks. The causality is envisaged in the case of
chemonecrosis and burns. It would be strongly presumed in a civil procedure in
case of non-approved equipment. The authors are in favour of a hypothesis of a
burn and review the current state of ultrasound liposuction, which was the
subject of an intense media campaign several years ago.
PMID- 9768134
TI - [Hypoglossal-facial anastomosis. A report of 60 cases].
AB - The authors report their experience of 60 cases of hypoglosso-facial anastomosis.
The results of this retrospective series were analysed by the same examiner
according to the House and Brackmann classification. The surgical technique is
rapidly described, with emphasis on the important points. The results are
analysed as a function of the interval between the anastomosis and facial
paralysis: better and more rapid results are obtained when surgery is performed
early (80% of grade 3 with immediate surgery versus 50% in very late surgery
after more than 4 years). However, grade 3 or 4 can be obtained in every case,
even in the case of very late surgery. Other favourable prognostic factors were
revealed by this study: specialized rehabilitation and especially the patient's
psychological must be integrated in this nerve transfer. In view of these good
results and the limited adverse effects (atrophy of the hemi-tongue, eye-mouth
synkinesias), hypoglosso-facial anastomosis must be part of the therapeutic
strategy of total, permanent facial paralysis.
PMID- 9768135
TI - [Lengthening of temporalis myoplasty and reanimation of lips. Technical notes].
AB - The author reports a new myoplasty technique which separates the temporalis
muscle from the temporal fossa and allows lengthening by redistribution of
muscular fibers to the detriment of the posterior third. This allows the transfer
of the coronoid tendinous insertions onto the lips. This technique preserves the
two neurovascular supplies and does not distort the cheek. The indication
purposed is lips reanimation.
PMID- 9768136
TI - [Antley-Bixler syndrome. Description of two new cases and review of the
literature. Prognostic and therapeutic aspects].
AB - Antley-Bixler syndrome was first described in 1975, and to date, 20 cases have
been reported. In addition to brachycephaly, the syndrome is associated with
midface hypoplasia often with choanal stenosis or atresia, bilateral radiohumeral
synostosis, multiple joint contractures, femoral bowing and long bone fractures,
"pear-shaped nose", dysplasic ears, and occasionally urogenital or cardiac
defects. Survival is closely linked to upper airway obstruction, which also
affects (with craniosynostosis) mental prognosis. Association and severity of
malformations are variable, and while numerous children have died early from
respiratory distress, one third of them are alive, and have had quite
satisfactory development. With early and effective prevention of respiratory
complications, and early treatment of craniosynostosis, overall prognosis can be
favorable. The mode of inheritance is probably autosomal recessive and
midtrimester prenatal diagnosis is feasible; genetic counseling depends on
accurate prognostic and therapeutic data. We describe 2 further cases. The first
a 4 years old male, with unilateral coronal synostosis and radiohumeral
synostosis predominating on the same side. The second an 18 months old female,
with brachycephaly and an imperforate anus.
PMID- 9768137
TI - [Plantar verrucous carcinoma. A case report and literature review].
AB - The authors report a case of carcinoma cuniculatum plantar and review the
literature on this rare tumour. The clinical features and course of this tumour.
The clinical features and course of this tumour are successively described.
Although associated with limited malignancy and almost exclusively local
extension, progression of this disease may lead to amputation, which can be
avoided by early diagnosis, especially based on precise histological examination
of all tumours with a benign recurrent appearance after well conducted treatment.
PMID- 9768138
TI - [Anatomo-clinical study of the inverted fascia-subcutaneous leg flap].
AB - The authors report their experience in the use of the reversed fascio
subcutaneous flap of the leg in 11 cases for covering soft tissue defects of the
distal third of the leg, the malloli and the posterior heel. An anatomical study
has been performed on fifteen fresh cadavers (30 legs), in order to precise the
indications and limits in the dissection of the flap pedicle. The authors report
six necrosis (2 superficial, 4 total) of the distal part of the flap. Despite
these complications, they consider that this flap is an interesting procedure due
to its advantages: the respect to anatomical structures, an easy dissection, a
supple pedicle and an aesthetic aspect of the donor area.
PMID- 9768139
TI - [Covering of a thoraco-lumbar defect by omentoplasty].
AB - With a case of thoraco-lumbar defect, the authors discuss about different
procedures to cover it. In this place, the better procedure is certainly the
latissimus dorsi flap, in all combinations. The indication for omentoplasty at
this spinal site should not be performed by first intention but by exclusion of
other procedures, as in the case considered by the authors. It was a 37-year-old
man, paraplegic from the age of 16, with a deep chronic spinal wound, secondary
to sepsis of a posterior segmental fixations. A staphylococcus aureus infection
which developed as a surgical complication was initially treated with antibiotics
and surgical cleaning procedures without removing instrumentation. However, the
infection remained active and the material was finally removed. Spinal
immobilisation was strengthened by external fixation. The area was cleared of all
suspect material, including bone graft, leaving a wide back-wound open to the
spine. Spontaneous healing was first attempted, but the size and the chronicity
of the wound led us to use pedicled greater omentum to close the defect. The
omentum was pedicled on the right gastroepiploic vessels and transferred to the
back wound through the posterior abdominal wall muscles, next to the right
kidney. This procedure allows rapid healing. In association with suitable
antibiotics, it has prevented any recurrent infection after 18 months of follow
up. It was no feasible to cover the wound with a latissimus dorsi flap,
considering the importance of this muscle in the movements of a paraplegic and
considering the initial impossibility of removing the external fixation.
PMID- 9768140
TI - [The history of cranioplasty].
AB - Cranioplasties were first performed at the dawn of the history of medicine, as
they usually constitute the repair phase of trephination. In preColumbian
civilizations, they usually consisted of simple interposition of metal sheets
under the scalp. Hippocrates and especially Galien prohibited this surgery and
their principles were respected until the 18th century, although a remarkable
surgeon, Van Meekeren, succeeded in performing a heterologous cranial bone graft
from dog to man in 1668. The discovery of the osteogenic role of periosteum by
Duhamel in 1742 opened the way to new research. During the 19th century, there
was an extraordinary growth of science, during which all of the bases of the
modern medical approach were established. For example, the studies by Ollier in
1859 allowed the first cranial reconstructions by heterologous, homologous and
autologous bone transfers. The large number of head injuries left by the First
World War promoted the growth of bone cranioplasties, as shown by Delageniere.
The discovery of antibiotics allowed the reintroduction of cranioplasties using
inert materials such as acrylic resins. However, their excessive use was
complicated by numerous cases of infectious rejection. At the end of the 20th
century, microsurgery and molecular biology have provided solutions, but have
still not resolved the dilemma between reconstructions by autologous or foreign
materials.
PMID- 9768142
TI - [On breast implants].
PMID- 9768143
TI - [Breast reconstruction after mastectomy and breast implants. Current status in
the USA].
AB - The author review breast reconstruction after mastectomy for cancer, taking
account the technical progress and problems raised by breast implants over the
last twenty years. Immediate breast reconstruction has become a routine clinical
practice. The principle, indications and complications of reconstruction
techniques are presented: temporary expansion prosthesis, permanent expansion
prosthesis, latissimus dorsi myocutaneous flap associated with an implant, rectus
abdominis myocutaneous pedicle flap, free flaps.
PMID- 9768144
TI - [Silicone breast implants and breast cancer].
AB - The authors discuss the immunological and oncological risk of prefilled silicone
gel breast implants. A comparative study of 146 patients undergoing breast
reconstruction by silicone implant at the Institut Gustave-Roussy and 146 matched
controls demonstrated the absence of any difference between the two groups
concerning survival, local recurrence rate and metastases.
PMID- 9768145
TI - [Breast reconstruction after breast cancer: a review of a 12-year-long
experience].
AB - The experience of 428 mammary reconstructions (MR) performed by the same surgeon,
evaluated more than two years after surgery, enable the authors to try to
determine possible correlations between results of MR and methods employed.
Antibiotic prevention and tissue expansion only appear to have a significant
influence on MR issue, whereas capsular contracture and aesthetic result did not
seem correlated with prior radiotherapy or texture of the wall implant. This
study confirms the low morbidity of MR. As regards quality of life, MR provides a
noticeable benefit to a wide majority of patients. No method has been proved to
be higher, or not advisable, against others. So, indications must be modulated in
every case, patronizing better compromise between safety, quality and stability
of morphologic result, and need expressed by each patient.
PMID- 9768146
TI - [Breast reconstruction with the autologous latissimus dorsi flap. Preliminary
report of 60 consecutive reconstructions].
AB - Many women who have undergone or will undergo mastectomy request breast
reconstruction and feel that it is an important part of their total cancer
treatment. Autogenous tissue methods take a place more and more important in
breast reconstruction. The autologous latissimus dorsi flap, is a recent method
of autologous breast reconstruction. We have done a retrospective study based on
a series of 60 consecutive reconstructions operated between march 1993 and april
1995. The advantages of the autologous latissimus dorsi flap are the same of the
others autologous breast reconstruction methods: the reconstructed breasts are
soft and match an opposite normal breast more successfully than those made with
implants. The disadvantages of this technique is mainly the dorsal seroma that
was observed in 70% of cases but was easily managed by aspirations. The
aesthetics results have been judged by two surgeons as very good in 85% of cases,
good in 11.6% and low in 3.3%. The satisfaction rate of the patients in high:
86.6% are pleased and 13.3% are satisfied. The autologous latissimus dorsi breast
reconstruction is a safe and reliable technique and provides an excellent
alternative to the TRAM flap, when the patient prefer the dorsal donor site or
when there are some risk factors to do a TRAM flap. Finally this technique bring
a major advance in the field of breast reconstruction, immediate or delayed.
PMID- 9768147
TI - [Complications and abdominal wall sequelae in pedicle TRAM breast
reconstruction].
AB - The doubts concerning silicon implants since 1991 have led to the development of
autologous tissue reconstruction and especially pedicle rectus abdominis flap
(TRAM). The good cosmetic results obtained on the reconstructed breast also
promoted the development of this technique. However, the complications and donor
site sequelae must not be underestimated. The abdominal wall is considerably
modified in terms of muscle strength and residual scars. It can be the site of
complications such as herniae and scar necrosis. In order to more accurately
assess these risks, the authors studied a series of 251 TRAM breast
reconstructions performed at the Institut Gustave-Roussy between 1982 and 1992.
The rate of herniae requiring reoperating decreased considerably with improvement
of the technique, falling from 10% to less than 2% in the most recent cases, with
a mean rate of 7% for the overall series. Infraumbilical scar necrosis was not
exceptional, but the incidence appeared to decline with the surgeon's experience
(about 5%). This depended on the patient's clinical context, especially a history
of smoking. The strength of contraction of the upper segment of the muscle was
significantly decreased and the cosmetic results of the abdominal scar were not
always favourable as they were considered to be satisfactory in only 70% of
cases. This study demonstrates the importance of not underestimating the sequelae
of donor site scars, which must be taken into account when evaluating the results
of the technique.
PMID- 9768148
TI - [Functional evaluation of the abdominal wall after raising a rectus abdominis
myocutaneous flap].
AB - Breast reconstruction with transverse rectus abdominis muscle (TRAM) flap raises
two contradictory questions: the vascular safety of the flap and the late
abdominal wall sequellae. In order to analyse these sequellae, 71 patients with
TRAM flap breast reconstruction at the Institut Curie had a late postoperative
evaluation by both a physiotherapist and a surgeon, an average 28 months after
their reconstruction. 12 had had a double pedicled TRAM (DPT) and 59 a single
pedicled TRAM (SPT). Hernias and bulges were systematically recorded, and all
patients had an evaluation of their abdominal wall function by questioning
(subjective evaluation) and muscular testing (objective evaluation). The overall
hernia rate (including bulges) was 5.6%. This rate was 2.5% when mesh was used,
and 9.5% when direct closure was performed. This hernia rate was not influenced
by the type of TRAM (SPT or DPT). 20% of patients complained of residual
abdominal pain, and 36% of a decrease of their abdominal strength after SPT. Both
these figures were 75% after DPT. Testing showed that these sequellae were
related to an impairment of the supraombilical portion of the rectus, this
impairment being much higher after DPT than SPT: none of the 12 patients with DPT
were able, from a lying position, to sit down without using their hands (not
reaching 4 in Lacote's test), whereas 47% of the SPT could do it. The oblique
muscles were also impaired, as less than 20% of patients reached Lacote 4.
However, this impairment was not influenced by the type of flap harvested.
Testing was also equivalent after both techniques of SPT (standart or
"supercharged"). The post-operative hernia rate was not higher for DPT and seemed
related to the technique used for abdominal wall closing (mesh vs direct
closure). However, the functional sequellae (pain, muscle strength decrease) were
much higher after DPT than SPT. It thus confirms us in our attitude to restrict
the indications of DPT, when feasible, to the profit of microsurgical flaps.
PMID- 9768149
TI - [Rectus abdominis free flap breast reconstruction. A series of 23 cases].
AB - Free TRAM flap breast reconstruction was performed in 23 patients from july 1993
through november 1995 at the Saint-Louis Hospital in Paris. The surgical team was
composed of eight different surgeons. In all cases a delayed breast
reconstruction procedure was performed. All patients in this series had
previously received radiation therapy and 82.6% patients presented with excess
body weight. Decision to perform a free flap procedure was confirmed
peroperatively under two conditions. Adequate caliber of the donor and recipient
vessels was required, allowing the anastomoses to be performed without
magnification in most cases. Preservation of the thoraco-dorsal vessels was the
rule so as to allow later use of a latissimus dorsi flap if necessary. Thus in 8
of the 31 cases in which a free flap was initially indicated a pedicled flap was
actually performed so as to satisfy the above conditions. All procedures were
performed by two surgical teams working simultaneously. Flap harvest met local
tissue requirements in all cases. A lateral strip of rectus abdominis muscle and
fascia was preserved when this appeared feasible. The abdominal wall was
reinforced by prosthetic means in 82.6% of cases. The average operative time was
9 hours. Results were considered satisfactory or very satisfactory in most cases.
The complication rate was 39.1%. Among the complications noted were 1 case of
partial flap necrosis, 1 case of fat necrosis, 1 abdominal hernia, 1 abdominal
bulge (both abdominal complications occurred in patients in whom no prosthetic
material was used for abdominal repair). This complication rate also includes
revision of the microsurgical anastomoses in 2 cases; in both cases the flap
survived completely. This study tends to suggest that the free TRAM flap for
breast reconstruction is a reliable technique. It is the authors' belief that it
should replace the bipedicled TRAM flap since it combines ample flap
vascularization with minimal rectus harvest.
PMID- 9768150
TI - [Preservation of the muscle in the use of rectus abdominis free flap in breast
reconstruction: from TRAM to DIEP (Deep inferior epigastric perforator) flap.
Technical notes and results].
AB - The advantages of TRAM (Transverse Rectus Abdominus Muscle) flap for breast
reconstruction is now well recognised. This technique allows a cosmetic
reconstruction with a more natural shape than with conventional reconstruction
with prosthesis. However the disadvantage is the need of removal of part or all
rectus abdominis muscle. If the techniques of free flap are now recognised to be
more reliable than pedicle TRAM they have not demonstrate a superiority in term
of parietal sequellae. To avoid such problem some teams have progressively
developed the DIEP (Deep Inferior Epigastric Peforator Flap). This flap is
harvested only on the transmuscular perforators. We are presenting here our
expertise which progressively has leed us from free partial TRAM to DIEP. From
december 1995 to january 1997 we have practice 18 breast reconstructions with
free flap. On 13 DIEP we had only one parietal complication due to incomplete
closing of the aponeurosis at the lowest part of the surgical approach. This
complication was easily corrected as the muscle was still tonic. On 5 TRAM,
clinical examination finds parietal weakness on 3 cases. We believe that this
technique is full of promises as it brings autologous tissue with no complication
on donor site.
PMID- 9768151
TI - [Mammoplasty for symmetry of the contralateral breast and its oncologic value].
AB - Controlateral occult carcinomas are observed in 3 to 5% of the reduction
mammaplasty of the controlateral breast at the time of the breast reconstruction.
The symmetry procedure allows a good check up of the glandular tissue of the
controlateral breast, especially when there is no evidence of tumor. The
different techniques of breast reduction provide specific possibilities for such
exploration and should be chosen according to the area which should be explored.
The superior pedicle technique gives us the best exposure and an easier
modelling. It gives a good aesthetic results in 80% of cases. The central pedicle
and dermoglandular pedicle technique give a good exposure and permits us to fill
the defect with glandular flap. The drawback of the inferior pedicle technique is
the lack of control of the central and inferior quadrant.
PMID- 9768152
TI - [Role of plastic surgery in the conservative treatment of breast cancer].
AB - Conservative surgery (CS) is widely accepted today as the treatment of choice for
60 to 80% of the primary breast cancer. Esthetic results of CS are not good in
all the cases and improvement can be obtained thanks to the remodelling of the
breast after tumorectomy. The scar should be selected according to the location
of the tumor; the glandular tissue should be reshaped using local glandular flaps
or following the principles of the reduction mammaplasties. Tumorectomy located
in the upper part of the gland can be reshaped with an inferior pedicle type of
mammoplasty. Defect located in the inferior part of the gland can be
reconstructed with a superior pedicle mammoplasty. These sophisticated
tumorectomies are providing good esthetic results on the reconstructed breast but
require commonly a symmetry procedure on the contralateral breast. Such
contralateral reduction allows a better exploration of the opposite breast and
histological examination of the reduction specimen. In a series of 76 CS
performed at the European Institute of Oncology (IEO), which were associated with
some kind of plastic procedure to lower the risk of bad cosmetic results
(representing 25% of the CS associated with plastic surgery), we confirmed the
value of the mixed oncologic and plastic approach. The esthetic results observed
in this series are better than those observed in another series previously
published at the Gustave-Roussy Institute (IGR)--good results: 72% (IEO) vs 50%
(IGR), and bad results: 6% (IEO) vs 20% (IGR). Statistically such comparison can
be criticised, specially because of the short follow-up of the Milan series.
However, the difference is rather important if we consider that the series of
Milan was a selection of cases with poor esthetic expectation (25% of all the CS
performed during the same period), while the series of Paris did not select the
patients in what concerns the risk of poor esthetic result.
PMID- 9768154
TI - [Internal supporting mammary lamina. Results of the detection of breast lesions].
AB - In order to stabilize the curves of a surgically remodelled breast, Bustos
associated to a periareolar mammaplasty a synthetic internal supporting lamina.
At the beginning, in 1985, a smooth perforated silicone sheet was used. Since
then, other materials were proposed (radioopaque ou radiotransparent, resorbable
or not). Because of their superficial situation, in front of the mammary gland,
it was essential to study the consequences of the presence of such a material on
the mammographic follow-up. We radiographied all the different types of sheet in
vitro, and also in vivo, 3 to 19 months after surgery. At the same time we
studied the modifications in the breast tissue, in 117 patients after surgical
treatment for ptosis or mammary hypertrophy, using different kinds of incisions
(periareolar or anchor-shaped, J or L shaped, inferolateral oblique or lower
vertical incisions). We also studied the effects of mammary implants covered with
Dacron, since some internal mammary supporting lamina are made with this
material. The silicone sheet gives some artifacts and may calcify. The resorbable
sheet has no effects on the mammography. The radiotransparent non resorbable ones
causes no problems on short terms, but we are not sure whether some
calcifications appear on long term or not.
PMID- 9768153
TI - [Cutaneous suspension: immediate breast reconstruction with abdominal cutaneous
advancement using a non-resorptive mesh. Preliminary results and report of 28
cases].
AB - The immediate breast reconstruction with a definitive prosthesis (IBRDP) is the
most useful technique in our experience. We proposed a technique to allow the use
of IBRDP also in cases of mastectomy with large skin excision and also to permit
a better definition of the inframammary fold. The prosthesis pocket is prepared
as usually with the pectoralis major and serratus anterior muscles and then, a
skin flap is undermined about 6-8 cm below the inframammary fold to prepare an
upper abdominal skin flap. The innovation point is the use of a triangular non
absorbable mersilene mesh to pull up and maintain the flap. The mesh is initially
sutured at the future inframammary fold projection 4 to 6 cm lower than the
previous inframammary fold and sutured under tension to the third and fourth
costal cartilages. The prosthesis is located in front of the mesh and behind the
muscles. Twenty nine patients had a mastectomy with IBRDP with the "Cskin
suspension" technique at European Institute if Oncology (IEO) from june 1995 to
september 1996. Only one case (3.4%) had a prosthesis loss 3 months after the
surgery, probably by a prosthetic material rejection. This technique permits an
IBRDF for the patients with a good abdominal skin laxity and also avoids the use
of a more complicate or a more expensive technique (myocutaneous flaps or skin
expanders). The small post-operative complications rate must be confirmed by a
larger follow-up to evaluate the capsular contracture rates and the final
cosmetic results.
PMID- 9768155
TI - [A rare breast tumor...].
PMID- 9768156
TI - [Statistics and breast implants].
AB - The author presents his point of view concerning the incidents and complications
of augmentation mammoplasty which he has seen and treated over the 35 years of
his career. He questions the basis of certain generally accepted ideas,
prospective analyses deduces from statistics subject to criticism in terms of
"publicity" or the interests of companies manufacturing breast implants or the
regrettable incompetence of the authorities supposed to verify the quality of
these implants.
PMID- 9768157
TI - [Orbital decompression in exophthalmos due to thyroid disease. Report of 69
cases].
AB - Dysthyroid exophthalmos is due to mismatching of the orbit and its contents,
essentially due to muscle enlargement, and, to a lesser degree, fat volumetric
changes. Surgical treatment is designed to expand the orbital volume by bone
removal or to reduce orbital contents by fat removal, or a combination of the two
techniques. Our series consisted of 69 patients who underwent orbital
decompression for proptosis, with osteotomy (12 cases) or associated with fat
removal (57 cases). We obtained good results for all cases, and did not encounter
any complications. Several factors now appear to play a role in the choice of
surgical technique, particularly the preoperative radiologic (CT) examination
which determines the muscular and fat involvement, wall orbital changes and
appearance of the sinuses. Orbital fat removal seems to be useful in proptosis
reduction in those cases in which fat is more involved and easy to remove.
Anthral ethmoidal decompression is the best technique in the case of dysthyroid
optic neuropathy.
PMID- 9768158
TI - [Role of coral blocks in cheek augmentation surgery. Prospective study of 23
patients].
AB - A two-year multicentre prospective study was performed from 1992 to 1995 in order
to evaluate the real value of various kinds of coral blocks as bone substitute in
maxillofacial surgery. This study was supported by the French National Agency for
Research Valorization (GBM/TEP procedure). Ten Maxillofacial Surgery Units were
included. During this time, 28 coral blocks (23 patients) of two different shapes
were used as malar implants for correction of congenital or acquired zygomatic
hypoplasia. The mean follow-up was 1.8 year (min: 1.5; max: 2). The tolerance was
perfect for 89% of cases. The radiologic opacity never decreased more than 30%
and the volume augmentation was always stable at the end of the follow-up period.
Three implants were removed because of septic complications. Rigid fixation
between the implant and the zygomatic bone appears to be the most important
factor of success. On the other hand, the surgical approach (endo- or exo-buccal)
does not seem to influence the success rate. The aesthetic improvement was always
evaluated as satisfactory and stable by the patients and the surgeons. The
authors discuss the real value of the various kinds of biomaterials and
especially coral, comparing their personal data with those of the literature.
Coral blocks clearly constitute a safe and reliable bone substitute, but further
investigations are required to determine its long-term behavior.
PMID- 9768159
TI - [Posterior marginal mandibulectomy for cancer of the oral cavity and oropharynx.
Experience with 14 clinical cases].
AB - Marginal mandibulectomies are now widely performed in the anterior aspect of the
mandible providing that the preoperative clinical and radiologic evaluation shows
no bone invasion. These marginal resections can be extended to the posterior
area. Molar, retromolar and ascending ramus resections can be performed. This
removes the upper bone segment preserving the dental canal whenever possible.
From 1990, 14 patients were treated with this technique for carcinoma of the
retromolar triangle (9 cases) and oropharynx (5 cases). 11 different flaps were
used to cover the soft tissue defect and 3 direct sutures were performed. Eleven
patients underwent postoperative radiotherapy with a mean dose of 58 Gray. Median
follow-up was 32 months. Functional and cosmetic results were very satisfactory
due to preservation of mandibular continuity. We found no osteomyelitis,
postoperative fracture or radionecrosis. This technique avoids a segmental
resection in some well-defined cases and the disability produced as a result of
this treatment. There is therefore, no need for complex reconstruction and the
operating time is shortened in fragile patients.
PMID- 9768160
TI - [Use of deformities in the treatment of facial skin defects in children:
"deforming resections". Report of 35 cases].
AB - Spontaneous resolution of deformities after excision of facial skin lesions has
been known and used for a long time by plastic surgeons. The resorption mechanism
of deformity is based on natural skin expansion, and seems to be directly related
to the action of the muscles of facial expression and their skin relations.
Natural expansion has been shown to be effective in children. Between 1990 and
1994 excision of skin lesions, including congenital nevi, leading to
postoperative deformity of the cheek, labial commissure, nose, eyelid and
forehead, was performed on 35 patients, aged from 3 month to 12 years. The
average follow-up is 24 months. For 26 patients (74%), natural resorption was
observed 4 or 6 weeks later with good aesthetic results. For 6 patients (17%),
the deformity persisted 3 or 6 months later, but did not require any further
surgery. For 3 patients (9%), a second operation was necessary. Using the skins
natural capacity for expansion in the treatment of facial skin defects in
children is a method of reconstruction which has already been used for excision
in enforced position. The platysma and muscles of facial expression by their
action on skin mobilisation, allow natural expansion. A better knowledge of
cutaneous biomechanical properties enables plastic surgeons to find an
alternative to other classical methods.
PMID- 9768161
TI - [Mammaplasty with triple interposition of glandular flaps. Technical note].
AB - The unfavorable breast contours resulting from a reductive mammaplasty or a
mastopexy influenced the authors into developing a technique that provided
reduction of the breast base and axillary pole, convenient medial position of the
lateral pole and substantial conification of the breast tissue to help project
the areolomamillary complex to the apex of that cone. From March 1987 to May 1996
two hundred and seventeen operations were performed with this technique that
consists of construction of three glandular flaps and maximum preservation of the
skin covering. The results obtained showed to be very satisfactory and more
lasting.
PMID- 9768162
TI - [Decubitus ulcers of the buttocks: our therapeutic approach in the course of the
last ten years. Report of 32 cases].
AB - The authors conducted a retrospective study of 80 cases of pressure sores of the
pelvic girdle. This study was designed to evaluate the therapeutic approach,
surgical reconstruction techniques and their results at 1 year. Only 32 patients
(40%) underwent surgical reconstruction, always using regional pedicled
myocutaneous flaps. 15.6% of these patients developed a local recurrence (5/32).
Analysis of the results of this series shows that failures of reconstruction
cannot be attributed to surgical techniques, but to their indications. The
reduction of recurrences depends on earlier medical and surgical management and
more rigorous patient selection, especially concerning psychological aspects. The
patient's cooperation is an essential condition to the success of treatment.
PMID- 9768163
TI - [Distal extensor digitorum brevis muscle flap. Report of 2 cases].
AB - The authors describe an original technical modification of the extensor digitorum
brevis muscle flap. As described, its use in a classical reverse flow manner
allows the flap to reach only the metatarsophalangeal joints. The presence of the
first dorsal interosseous pedicle offers the possibility to sacrifice the plantar
anastomoses of the pedis pedicle and raise the flap on the vascular network of
the first metatarsal space. The point of rotation is moved distally from the apex
of the first metatarsal space to its base. The length of the vascular pedicle is
substantially enhanced and enables the flap to cover all dorsal and palmar
defects of the toes. Two clinical cases are showed. The advantages of this flap
are discussed, particularly its indication in reconstructive surgery of the foot.
PMID- 9768164
TI - [Anatomical study of interosseous flaps and the concept of postero-anterior
interosseous flap. Preliminary report].
AB - The postero-anterior interosseous flap uses the distal network of the posterior
and anterior interosseous arteries. With this flap the authors would like to
point out all the possibilities of reverse fascio-cutaneous flaps offered by the
interosseus arteries. An anatomic study has been carried out with both a
literature review and a cadaveric study. The authors studied the distal
interosseous anatomy on 40 fresh upper arms after colored latex injection of the
anterior interosseous artery near its origin. A distal anastomosis between
anterior and posterior interosseous arteries was present in 38 cases. This
anastomosis was situated at an average of 25 mm from the radio-carpal joint. The
authors found the fascio-cutaneous artery branch of the anterior interosseous
flap in 40 cases, but its origin is variable. Therefore, the anterior
interosseous flap was possible in every case but the pedicle length was variable.
The surgical technique must begin by a distal exploration of the vascular
network. After this exploration the flap is chosen in function with the anatomic
possibilities and the cutaneous defect. The authors have already used several
kinds of reverse interosseous flap: anterior (6 cases), posterior (11 cases) and
recently, postero-anterior (2 cases). With the postero-anterior flap the authors
will show the large range of flap possibilities offered by the interosseous
arteries for the cutaneous defects of the dorsum of the hand.
PMID- 9768165
TI - [State-of-the art on rhinoplasty, facial rejuvenation and breast augmentation.
Antibes, Juan-les-pins, 24-26].
PMID- 9768166
TI - [Occipital pedicle forehead flap].
PMID- 9768167
TI - [Skin necrosis after ultrasound lipolysis].
PMID- 9768168
TI - [Results of biplane face lifts with maximal skin underlining and vertical SMAS
flap].
AB - It is difficult to evaluate the medium and long-term results of facelift due to
loss to follow-up of a large number of patients. The authors developed a
questionnaire which they sent to their patients. 148 patients (143 women and 5
men) answers this questionnaire and 54 patients returned for review. This
subjective evaluation of the results nevertheless had the advantage of
identifying three target organs specifically treated by the surgical techniques
used: the nasolabial folds, the jowls and the neck. Improvement or deterioration
of the results was therefore evaluated and reported on a series of tables. The
results are analysed in this paper. 70.3% of patients studied reported a
satisfactory objective result with a mean follow-up of 26.8 months. The least
favourable results were observed in the neck, due to the small number of
technical procedures performed on the platysma, which would appear to justify
greater surgical attention. Among the complications reported, 9.2% of cases
indicated inadequate results, especially concerning the "lion's wrinkle", which
emphasizes the value of a complementary endoscopic procedure at this site.
Perioral wrinkles were a source of dissatisfaction in 14.8% of cases, and can be
treated by dermabrasion. Lastly, a number of minor complications such as
malposition of the ear lobe, facial redness or scar abnormalities were also
mentioned and are easily accessible to an ambulatory secondary improvement
procedure. This study therefore validated the operative technique of biplane
facelift with a satisfactory stability of the results over time. Objective review
of dissatisfied patients, who generally returned for review after receiving the
questionnaire, led to a number of reoperations, which appear to be useful in the
case of early deteriorations occurring during the first postoperative year and
which concern about 5% of patients. The ultimate objective of this paper was to
try to establish a methodology for the analysis of the long-term results of
facelift, without directly involving the examiner or operator, who may ignore
what the patient really feels.
PMID- 9768169
TI - [Pathogenesis and treatment of the nasolabial fat pad: nasolabial dermolipopexy].
AB - The author presents an original technique designed to control the nasolabial fat
pad, which often becomes organized in the form of a fatty tube. Following sub
adipose facelift, the principle of this technique consists of opening the fat
pad, then suspending it to the inferior orbital margin by a U-shaped suture
anchored onto a plastic plate placed on the skin.
PMID- 9768170
TI - [Isolated cervico-facial liposuction applied to the treatment of aging].
AB - Almost 20 years after its first application, liposuction is today a procedure
commonly used on the cervicofacial region. This article emphasizes the importance
of the isolated liposuction in the rejuvenating treatment of the face.
Liposuction allows the correction of the fattening of the contours, but also of
the sagging of the teguments thanks to the skin retraction. The reconstruction of
a tridimensional image shows the importance and the constancy of the adipose
tissue in the whole face, even in thin ones. The limits of this method are
related to the existence of a skin with a sufficient elasticity of a not too
important skin excess, and of a sufficient subcutaneous adipose tissue. In
selecting the orientation of the tunnels according to the lines of skin tension,
we are determining the concept of an orientated skin retraction. In the
conclusions, the isolated tunnelization of the face, with or without liposuction
seems to be a solution allowing either to delay for several years the time for
facelift, or to suggest an alternative choice for patients who refuse or fear the
principle of a facelift.
PMID- 9768171
TI - [Silastic implants and reconstruction of the orbital floor: review of twenty
year's experience].
AB - Fractures of the orbital floor still raise unresolved therapeutic problems
concerning the operative indication or the type of material to be used during
repair. For this purpose, surgeons have the choice between heterologous or
autologous grafts, implants and numerous biomaterials. The authors conducted a
retrospective study with a follow-up of 20 years of 137 patients treated in the
department for a fracture of the orbital floor using a Silastic implant. The
reoperation rate to remove the implant was 13.8%. Various complications were
observed: dacryocystitis, migration of the implant to the skin and maxillary
sinus, cutaneous fistula, persistent diplopia, orbito-sinus communication,
periorbital cellulitis. In view of these complications, it appears preferable to
modify the therapeutic approach and propose autotransplantation of the concha for
defects less than 1.5 cm2 and autologous parietal bone graft for larger defects.
PMID- 9768172
TI - [Analysis of reconstruction procedures for defects of the mouth floor. Report of
96 cases].
AB - The aim of this study was to assess the reconstruction of floor of the mouth
defects after cancer surgery. The medical records of 140 patients treated between
January 1st, 1987 and December 31st, 1995 were reviewed. Ninety-six patients had
primary reconstruction: there were 82 cutaneous or osteomyocutaneous flaps and 14
microsurgical transfers. Among these patients 15 had titanium mandibular
reconstruction plates. The reconstruction procedures and postoperative follow-up
were evaluated. Healing by first intention is appropriate for superficial soft
tissue defects. The nasolabial flap is used only for small mucosal defects. A
forearm flap should be the first choice treatment for large soft tissue defects
owing to its plasticity and reliable vessels. Segmental mandibular resections
often imply mandibular reconstruction. Titanium plates may be used alone or with
a cutaneous flap. Tolerance of plates after radiotherapy is very good and they
are an effective method of reconstruction for fragile patients.
PMID- 9768173
TI - [Occipital forehead pedicle for one-stage repair of defects of the upper third of
the face].
AB - The authors describe a reconstruction technique for defects of the superior third
of the face using a fascio-cutaneous flap with a forehead paddle supplied by an
occipital pedicle. This flap has been successfully used in three cases to cover
defects of the temporo-zygomatic area indeed, the superior part of the cheek. Our
three patients presented recurrent cutaneous carcinoma, a local and general poor
condition. This process suits reliability and easiness to a good carcinologic,
functional and aesthetic result.
PMID- 9768174
TI - [Osteogenic capacity of a vascularized periosteal flap tubulized around a coral
implant. Experimental study on sheep].
AB - The objective of this study was to evaluate the osteogenic capacities of a
vascularized periosteal flap reinforced by a bone substitute, coral, to validate
the possibility of creating prefabricated bone flaps with shapes adapted to a
recipient zone, while limiting the donor site sequelae. 24 periosteal flaps, with
preserved vascular pedicles, were raised from the medial femoral epiphyses of 12
ewes. In the same animal, these flaps were reinforced with a cylinder of coral
and a cylinder of autologous graft. After implantation for 2 or 8 weeks depending
on the animal, the flaps were submitted to histopathological and
histomorphometric examination. The results of this examination demonstrated a
similar course of the flaps regardless of the type of reinforcement, both in
terms of implant resorption and the quantity of newly formed bone.
PMID- 9768175
TI - [Large abdominal wall reconstruction by free flap after recurrence of a
dermatofibrosarcoma protuberans].
AB - Based on a case of recurrence of a dermatofibrosarcoma protuberans of the
abdominal wall, the authors discuss the need for initial wide resection of this
type of skin tumour and the possibilities of repair of extensive full thickness
defects of the abdominal wall by means of a latissimus dorsi myocutaneous free
flap.
PMID- 9768176
TI - [Breast implants and their history].
AB - The controversy concerning breast implants has led to a profound change in our
surgical practice. Four years after the moratorium suspending the use of silicone
implants, the situation still remains confused. Polyurethane implants,
incriminated as being dangerous at the start of the anti-implant campaign, were
cleared by the FDA in 1995, but have not been re-released onto the market.
Silicone implants, the subject of a great many international studies on
carcinogenicity and immunological risks which failed to confirm these risks, are
now being used again throughout the world except in the USA, Canada and France.
Hydrogel implants, victims of the bad reputation of the other implants, were
suspended for dubious insurance reasons concerning the French Huriet law,
although they satisfy the clinical and laboratory criteria required for breast
implants. Only normal saline implants are currently used in France, although
their safety is only relative, as the reoperation rate for deflation is not
negligible. In our opinion, the Cronin type of bladder implant is obsolete and
the new available technologies must be used, although they raise an economic
problem following the overpublicized silicone implant catastrophe.
PMID- 9768177
TI - [About prions...].
AB - Iatrogenic Creutzfeldt-Jakob disease (CJD) was first reported in 1974, in a 55
year-old woman whose symptoms started 18 months following corneal implant
surgery. The transplant donor died of CJD. More recently, the epidemy of bovine
spongiform encephalopathy in the U.K., and the reported cases of iatrogenic CJD
due to extractive pituitary hormone injections, emphasized the problems of its
etiology and the way these neurodegenerative diseases get transmitted. A new
infectious pathogen was described as a prion: "small proteinaceous infectious
particle", responsible of transmissible neurodegenerative diseases. The lethal
evolution of these diseases, and the complete absence of preventive procedures
are fearful regarding the extension of the disease, specially during the
procedure of grafting originating from possibly infected people whose screening
is currently impossible. It is mandatory for the surgeon to update its knowledges
including the legal bylaws regarding a good surgical prevention. One must be
certain the implant, wether autologous or heterologous, is completely free of
disease, mainly in aesthetic surgery. This paper attempts to summarise this
topics. One must bear in mind that the current knowledges could soon turn
obsolete with a constant progression of scientific research and of the
epidemiologic data.
PMID- 9768178
TI - [The Ring test: a good tranquilizer, but a poor predictive test].
PMID- 9768179
TI - [Fasciola hepatica antigens. Use in the diagnosis of human fascioliasis].
AB - The ELISA technique was standardized for detecting antibodies against Fasciola in
25 serum samples from patients-infected with Fasciola hepatica using excretion
secretion antigens (ESA), tegument antigen and somatic antigen. A study was made
of serum samples from 46 patients with other parasites such as Ascaris
lumbricoides, Trichuris trichiura, Entamoeba histolytica, Schistosoma mansoni and
Giardia lamblia. The cohort value for each trial was established after studying
100 serum samples from healthy people as negative controls taking as criterion
the mean optical density plus 2 standard deviations from the mean. Regarding this
group and using ESA, we obtained specificity and sensitivity.
PMID- 9768180
TI - [Preliminary study of AP-64 cell line (Aedes pseudoscutellaris) for dengue-1 and
2 virus multiplication].
AB - We study a new arthropod cell line, AP-64, which was obtained from Aedes
pseudoscutellaris larvae. The best growth and maintenance media are defined,
testing the adequacy of dengue 1 and 2 viruses which become manifest by the
appearance of the cytopathogenic effect as syncytiums. The immunofluorescence
technique is applied to detect early multiplication of those viruses.
PMID- 9768181
TI - [Excretion-secretion antigens from adult Dirofilaria immitis in the diagnosis of
human filariasis by solid phase immunoenzyme assay].
AB - The solid phase enzymatic immuno-assay (ELISA) was normalized for detecting
antibodies against. Filaria using excretion-secretion antigens (ESA) from
Dirofilaria immitis adults in a group of asymptomatic and microfilaraemic
patients infected by different species of filariae (loa loa, Wuchereria
bancrofti, Onchocerca volvulus, Mansonella ozzardi and Mansonella perstans), and
in another group of symptomatic and aminorofilaraemic patients, temporary
residents in an area with endemic loiasis. The ESA-ELISA specificity permitted
the distinction between filariasic and non-filariasic patients.
PMID- 9768182
TI - [Some factors that influence acceptance of antimalarial chemoprophylaxis in
groups exposed to infection].
AB - 1,100 internationalist workers were surveyed in order to assess the factors
bearing upon the proper use of antimalarial chemoprophylaxis in endemic areas of
Africa. We detected difficulties concerning advisin and its quality. Most
subjects did not begin chemoprophylaxis before leaving Cuba, according to the
advice. It was proved that one third of them do not observe regularly this
prophylactic measure.
PMID- 9768183
TI - [Variation in organophosphate and carbamate insecticide resistance in relation to
esterase activity in Culex (c.) quinquefasciatus Say, 1823 (Diptera: Culicidae)].
AB - We determined the existence of the resistance mechanism by means of the esterase
enzymes in a Culex (C) quinquefasciatus stock established in the laboratory.
Bioassays were performed with insecticides such as malathion and temephos
(organophosphoric) and propoxur (carbomate); two cycles were completed during one
year. Resistance to malathion was higher. The presence of esterase enzymes in
this stock was determined by using synergits and starch gel and paper filter
electrophoresis techniques.
PMID- 9768184
TI - [Physiological age of 2 populations of Anopheles (N.) albimanus Wied., 1821
(Diptera: Culicidae) and its importance in malaria transmission].
AB - The physiological age of Anopheles albimanus in two villages of Havana Province
was studied. In general, we detected a similar pattern of behavior in the
species, with a higher number of females being born during the dry season, which
represents a higher risk of malaria transmission in this season.
PMID- 9768185
TI - [Use of an indirect immunofluorescence probe for early detection of latent
malaria].
AB - We followed up the values of the titres of malaria antibodies by the indirect
immunofluorescence (IFI) technique in 52 patients: 27 Cubans and 25 foreigners
with malaria. All the subjects had previously been in endemic zones. The
diagnosis of the disease was based upon the thick drop test. The prevailing
species was Plasmodium falciparum. The IFI technique was used at the beginning of
the treatment, weekly and after 3 months. Four patients had recurrences in the 3
first weeks of the follow-up, with increased levels of the antibody titres before
parasitaemia appeared. Those titres decreased with the specific treatment. We
propose that the patients with increasing antibody titres in spite of the
negative results of the thick drop test be considered as having a risk of
developing malaria.
PMID- 9768187
TI - [Isolation and identification of Vibrio genus microorganisms in the Quibu River].
AB - The Quibu River sewages were studied during 9 weeks, in order to isolate and
characterize Vibrio genus microorganisms. Twenty Moore's hyssops were placed 2 or
3 times a week on the banks of the river, where each of them was kept in a
passive capture stay for 24 hours. In all the hyssops placed, Vibrio cholerae non
01 were isolated.
PMID- 9768186
TI - [Esterase patterns in Culex (C.) quinquefasciatus Say, 1823, and its relation to
malathion organophosphate insecticide resistance].
AB - This paper describes the esterase patterns found in a wild strain of Culex
quinquefasciatus which was known to bear resistance genes and the existence of
genetic polymorphism for such esterases is demonstrated. The most frequent
polymorphisms found were Est-1, Est-2, and Est-3; Est-2 was possibly responsible
for Culex quinquefasciatus resistance. The frequency of potentially resistant
females was significantly higher as compared to males: in addition, the
hypothesis was proposed that heterozygotie Est-3 is selected as a genotype which
may contribute to resistance in neotropical areas.
PMID- 9768188
TI - [In vivo resistance to strains of Trypanosoma rhodesiense, Mozambique, 1985].
AB - We report the existence of high resistance to Melarsoprol and low resistance to
Suramin in 11 Trypanosoma rhodesiense species. They were isolated from humans in
the Tete province, Mozambique, and kept in mice at the Maputo National Health
Institute. The preliminary results obtained with Suramin administered
intracranially, are also reported.
PMID- 9768189
TI - [Ecological parameters of arbovirus circulation on the north coast of Havana. I.
Collection of culicids in the Guajaibon region].
AB - We show the culicids collected in the Guajaibon zone, in Havana Province, in
order to characterize the present population according to ecological parameters
and the possible risk for man. We show that Aedes scapularis is numerically and
ecologically dominant over the rest of the species that attack men, as well as
the possible indirect influence of culicid populations in crab caves upon human
beings.
PMID- 9768191
TI - [Shell identification of snail carriers of Fasciola hepatica in Cuba].
AB - We show the main conchiological characteristics of Fossaria cubensis (Pfeiffer)
and Pseudosuccinea columella (Say), intermediate hosts of Fasciola hepatica in
Cuba. Also, their qualification is compared with the species which are confused.
PMID- 9768190
TI - [Automated sentinel system of infectious diseases in Cuba].
AB - We state that the creation of the Automated System of Epidemiological
Surveillance should become an integral part of the Service of Hygiene and
Epidemiology of the Republic of Cuba, which allows for the operative evaluation
of the epidemiological situation in the country in order to take timely anti
epidemiological and prophylactic steps.
PMID- 9768192
TI - [Determination of glucose-6-phosphate dehydrogenase deficiency to prevent
possible drug-induced hemolysis].
PMID- 9768193
TI - [Isolation of hepatitis A virus in tissue culture. Preliminary report].
PMID- 9768194
TI - [Latin American Association of Mycology].
PMID- 9768195
TI - [Methodology for the epidemiologic study on acute respiratory infections].
AB - The foundations and methodology for an epidemiological study on acute respiratory
diseases are described. The study took place in 4 urban health areas in Havana
City and 4 rural doctor's offices in Matanzas. A discussion is carried out
regarding the intervention design for the staff of the health primary assistance
team headed by the family doctor.
PMID- 9768196
TI - [Infective capacity of the parasitic nematoda Romanomermis iyengari (Welch, 1964)
(Nematoda: Mermithidae) in mosquito larvae in natural conditions].
AB - The effectiveness of the parasitic nematoda Romanomermis ivengari (Welch, 1964)
was proved in 3 breeding sites of Anopheles albimanus (Wiedman, 1821) and Culex
Nigripalpus (Theobald, 1901) and 2 spillways for 2 oxidation ponds with Culex
quinquefasciatus (Say, 1823) larvae, in the Isle of Youth. The results of the
experiments showed the infesting capacity of this nematoda species with 80-100%
parasitism in A. albimanus and C. nigripalpus larvae, and 75-80% mortality for C.
quinquefasciatus. Besides, the recycling capacity of R. invengari, after its
introduction, was proved, confirming its possible use in the control of mosquito
larvae of medical-epidemiological importance in the Cuban tropical conditions.
PMID- 9768197
TI - [Use of a personal computer in the epidemiologic intervention on acute
respiratory infections].
AB - A discussion is carried out on the use of a general-purpose personal computer as
an aid for taking prophylactic and control steps in the face of epidemics due to
acute respiratory infections.
PMID- 9768198
TI - [Normalization and application of an ELISA ultramicro for the detection of herpes
simplex virus antibodies].
AB - An ELISA ultramicro was normalized for detecting herpes simplex virus antibodies.
A study was made on 145 samples from the Pedro Kouri Tropical Medicine Institute
and the Blood Bank, both by ELISA ultramicro and immunofluorescence and ELISA,
and 98% and 99% of coincidence was reached, respectively. It indicates good
correspondence between these techniques.
PMID- 9768199
TI - [Sensitivity of Mycobacterium fortuitum by the broth microdilution method
determining the inhibitory minimal concentration].
AB - A study was conducted on 40 Mycobacterium fortuitum strains isolated from
symptomatic patients suffering from respiratory diseases and skin lesions. Their
susceptibility to different antimicrobial agents was determined by the broth
microdilution method, measuring minimal inhibitory concentration. There was
sensitivity of the strains to gentamicin and tetracycline as well as resistance
to the tuberculostatic drugs used (isoniazid and ethambutol) and cefalotin.
PMID- 9768200
TI - [Detection of anti-Histoplasma capsulatum antibodies by the ELISA technique.
Preliminary study].
AB - An indirect micro-ELISA system is presented for diagnosing histoplasmosis. The
diagnostic criteria are defined by using sera from 12 patients who are
histoplasmosis carriers. For this group, the optical density values were superior
to 1,000; use was made of 43 sera from blood bank donors and 9 sera from children
without a history of exposure. The optical density values in these cases were
inferior to 0,200. The significant difference found led to the diagnostic
criterion for confirming 3 histoplasmosis carriers who showed clinical
manifestations but had been negative to double immunodiffusion. Thus, the
usefulness of the proposed micro-ELISA system for early diagnosis was proved.
PMID- 9768201
TI - [Knowledge and prejudice about leprosy in Havana City].
AB - One thousand two hundred sixteen people living in 6 representative municipalities
in Havana City were surveyed in order to know what they knew about leprosy and
how these patients are perceived by them. The purpose was to ascertain if the
community was prepared to help them to their adaptation to a socially useful
life, which is one of the tenets of the Program for the Control of this disease.
It was proved that only 10% had the necessary knowledge about leprosy and the
remaining 90% had wrong notions about it. It is concluded that the community is
not prepared for bringing about a change in the present status of this condition.
PMID- 9768202
TI - [Detection of cytomegalovirus in urine using DNA-DNA hybridization].
AB - A discussion is conducted on the results of the application of the technique for
hybridizing nucleic acids to the detection of cytomegalovirus (CMV) in urine
samples. For this purpose, 2 probes from 2 different regions of the genome of the
AD169 strain of CMV were used. The results were compared with those obtained by
the technique for the detection of early fluorescent antigens (DEFA) in 2 groups
of patients at risk of suffering from CMV infections. After assessing the
usefulness of the two probes in detecting CMV in urine samples, it was shown that
probe B from the region which codes the synthesis of early viral proteins had a
coincidence and specificity levels regarding the reference test (DEFA)
significantly superior to that of probe A. The results of hybridization may be
ready within 48 and 72 hours. The qualification of the technique fo its
application to virological diagnosis is discussed.
PMID- 9768203
TI - [Comparative study of serologic techniques for the diagnosis of human
leptospirosis].
AB - A comparative study was carried out in order to assess 3 serological techniques
employed at the Provincial Centers of Hygiene and Epidemiology for diagnosing
leptospirosis. The study included 49 sera from patients with leptospirosis
confirmed by the techniques of passive hemoagglutination (HA), plate macroscopic
agglutination with thermoresistant antigen (TR) and indirect immunofluorescence
(IIF). Sensitivity was 90% for HA, 96% for TR and 84% for IIF. IIF was performed
with the use of 5 different antigens and the highest serological reactivity was
obtained with the strain belonging to Canicola serogroup.
PMID- 9768204
TI - [CAMP factor for the differentiation among Aeromonas species].
AB - The CAMP factor technique, described by Natale Figura as a presumptive method for
the differentiation of the species hydrophila, sobria and caviae, was applied to
80 Aeromonas strains isolated from children under 5 years with acute diarrheic
disease. The typical phenomenon was seen in aerobiosis and anaerobiosis
conditions in 10 strains, which were classified as Aeromonas hydrophila. In
aerobiosis conditions/alone, it was observed in 20 strains, which were identified
as Aeromonas sobria. It was not observed in either of the incubation conditions
above mentioned in 50 of the remaining strains, which were identified as
Aeromonas caviae. The advantages of applying this new technique is emphasized.
PMID- 9768205
TI - [Identification of strains of beta-hemolytic streptococci of groups A, B, C, and
G by coagglutination].
AB - A study was conducted on the coagglutination (CoA) technique in the serogrouping
of betahemolytic streptococci of the groups A, B, C and G, previously identified
by physiological tests and the agar immunodiffusion technique. This technique was
used as a reference test and, according to its results, it can be stated that the
CoA technique allowed for the serological grouping in 95.7% of the strains. The
CoA technique was assessed by using reactions prepared in our laboratories and
the commercial kit Phadebact.
PMID- 9768206
TI - [Detection of anti-Cryptococcus neoformans antibodies in 3 groups of human sera].
AB - The tube agglutination (TA) technique was normalized in order to determine anti
Cryptococcus neoformans antibodies, according to Palmer et al., by employing
positive and negative control sera and an antigenic suspension prepared from an
autochtonous strain of Cryptococcus neoformans varneofornnans. Three groups of
human sera were studied and the role of TA in detecting antibodies in the group
of sera from patients with active cryptococcosis (100%) was shown. In sera from
banks positiveness was only 6%, while in the group of fowl breeders, considered
to be "exposed", positiveness was found to be 16%, although with low titres. A
discussion is carried out about the value of this technique as a complement in
the diagnosis and prognosis of cryptococcosis.
PMID- 9768207
TI - [Report on the therapeutic use of rimantadine and amantadine].
AB - A discussion is carried out about the experiences with the application of
rimantadine and amantadine to patients with influenza. The basic general results
consisted in the fact that 2 of the 74 patients treated had a high cure percent
(> 68.0%) within the first 72 hours after using the drug. No new diseased were
found among the 40 contacts to whom chemoprophylaxis was applied. There were only
3.9% adverse reactions among the total number of people treated with amantadine.
PMID- 9768208
TI - [Field trial of the Cuban recombinant vaccine against hepatitis B (Heberbiovac
HB). Study in newborn infants born to AgsHB+ mothers].
AB - A study was conducted on 106 newborns, whose AgsHB positive mothers received
active protection against hepatitis B (83 with the Cuban-produced Heberbiovac HB
vaccine and 23 with the Engerix-B vaccine manufactured by S. Kline as control
group, following the scheme 0, 1 and 2 months with the first dose administered in
the first 12 hours after birth. Samples were taken to study virus B markers at
birth (umbilical cord) after 30, 60, 90 and 180 days. Laboratory determinations
were carried out by the ELISA technique with diagnostic kits from the firm
Organon Tecknica. Ten or more IU/L of anti-HBs present in serum was considered as
the lowest protective level. Children were classified according to the AgeHB
present in mothers, AgsHB in the umbilical cord and the concentration of Ags HB
in maternal serum. 100% of the children who received the control vaccine showed
serological evidence of seroconversion to anti HBs with protective titres, and
the values of the geometric mean of the titres of antibodies were statistically
significant (p < 0.01) in all the extractions, favoring the Cuban vaccine. The
efficacy of the two preparations used in this research work was 100%. This study
makes it possible to report on a recombinant vaccine against hepatitis B
(Heberbiovac HB) which represents the first vaccine of this type produced in
Latin America, the efficacy of which was proved in the field trial.
PMID- 9768209
TI - [Stain hybridization method with pRepHind probe for the diagnosis of Plasmodium
falciparum].
AB - A study was conducted on the parasitemia detection level and the specificity of
the pRepHind DNA probe for diagnosing Plasmodium falciparum by the stain
hybridization method. The parasitemia detection level was studied by using
dilutions of a P. falciparum in vitro culture, adjusted by direct microscopic
examination to 1; 0.1; 0.01; 0.001; 0.0001 and 0.00001% of parasited red cells.
Specificity was increased by using DNA extractions from P. Yoelii, P. berghei and
human leucocytes. The results showed that the method was able to detect 0.0001%
of parasitemia starting from DNA extractions of 100 L infected red cells. The
pRepHind probe only detected specifically DNA from P. falciparum. It is concluded
that the method is suitable for being used in the diagnosis of infection due to
P. falciparum.
PMID- 9768210
TI - [Use of a dengue anti-complex monoclonal antibody in viral purification].
AB - The purification of different serotypes of dengue virus from a monoclonal
antibody which recognizes an epitope present in the four serotypes bond to a
Sepharose 4B matrix activated with cyanogen bromide, is reported. Results
evidence that the method employed makes quicker the process of purification with
a high degree of purity.
PMID- 9768211
TI - [Serologic marker as indicator of no circulation of poliovirus in Cuba].
AB - The surveillance of the circulation of the wild poliovirus is an essential
element for the eradication of poliomyelitis. The Pan-American Health
Organization emphasises on the etiological study of acute flaccid paralysis in
order to achieve this aim. The characteristics of our program against this entity
allowed to use the presence of antibodies in a sample obtained in February from
the infant population born on July during the previous year as criteria to know
the circulation of wild poliovirus. In 727 infants studies in the country (5% of
the total number of births during July), 99.1% showed no antibodies with a titre
equal or greater than 1:10. Low titres found in 7 infants were considered as a
remnant from maternal transmission. Results obtained represent a strong evidence
of the fact that there is no environmental circulation of poliovirus during the
period which had the greatest incidence of the disease.
PMID- 9768212
TI - [Obtaining a clone of the AP-61 cell line. Its usefulness in the multiplication
of dengue viruses 1 and 2].
AB - The obtention of a clone of the cell line AP-61 (Aedes pseudoscutellaris) is
reported. Details of the cloning and culture media employed are discussed.
Usefulness of the clone for the multiplication of dengue 1 and 2 viruses is
proved in comparison with the original line using the indirect immunofluorescence
technique.
PMID- 9768213
TI - [Characterization of monoclonal antibodies that recognize the thermolabile toxin
of Vibrio cholerae].
AB - The obtention of two monoclonal antibodies which recognize a single epitope
present in the subunit B of the thermolabile toxin of Vibrio cholerae and another
which shows a cross-reaction with those produced by certain enteropathogenic
toxins, is reported. The standardization of a solid phase indirect
immunoenzymatic assay (ELISA) for the primary screening and selection of hybrids
was performed; in addition, the isotype was determined.
PMID- 9768214
TI - [Phage typing of Mycobacterium tuberculosis using the overlay technique.
Preliminary study].
AB - One hundred and fifty strains of Mycobacterium tuberculosis were classified by
the phagotyping technique, using the double layer method described by Adams and
modified by Jones. The efficacy of this method was studies in comparison with the
method claimed by Redmond and Ward and traditionally employed for Mycobacteria
typing. Preliminary Results obtained have allowed to prove its advantages. A 96%
of coincidence with respect to the traditional method was reported.
PMID- 9768215
TI - [Standardization of an indirect ultramicro ELISA for the determination of total
antibodies against the measles virus].
AB - An indirect ultramicro ELISA system (UME) for the determination of antibodies to
measles virus by the cuban technology of Ultramicro Analytical Systems (SUMA) was
developed. A number of 448 serum samples from the National System of
Seroepidemiological Surveillance of Measles were simultaneously processed by the
Ultramicro ELISA system and by the haemagglutination inhibition technique.
Results were compared in both assays. Afterwards; 120 serum pairs obtained from
the same source were studies and processed in a similar way. Results evidenced
the usefulness of such immunoenzymatic system for the serological diagnosis and
the positive validation of replacing conventional techniques by this novel
technology.
PMID- 9768216
TI - [Serologic study for determining the circulation of respiratory viruses in Havana
City].
AB - During 1991, 2,400 serum samples from subjects under 15 years, and 2,400 serum
samples from subjects with the same age or over 15 years were assessed against
antigens of 7 respiratory viruses by the complement fixation test or by the
haemagglutination inhibition technique. The results from these investigations
allowed to determine the little circulation of the respiratory syncytial virus
which may result in an increase of a susceptible population and the occurrence of
outbreaks. The endemic state of Adenoviruses was determined and the subtype H1N1
of influenza viruses was found to have a little circulation with a raise in the
population under 1 year old age during November. The subtype H3N2 of influenza A
was the most important agent within the population studied, followed by Influenza
B virus during September and November. All viral agents were found to have
circulated in the different age groups of the population assessed.
PMID- 9768217
TI - [Non-tuberculous mycobacteria isolated in Cuba during the 1985-1989 period.
Preliminary report].
AB - A number of 1,061 strains of nontuberculous mycobacteria referred to "Pedro
Kouri" Institute of Tropical Medicine during the period of 1985-1989 were
studied. Strains were from Provincial Centers of Hygiene and Epidemiology of the
country. According to the results obtained, most of the strains classified are
found in groups III and IV according to the criteria of Runyon (54, 76, and 36%,
respectively). Species with a greater frequency belong to the complex MAI and M.
fortuitum.
PMID- 9768218
TI - [Serologic response to some herpesviruses in a group of HIV infected patients].
AB - The titres of antibodies to the herpes simplex virus, cytomegalovirus, and the
antigen of viral envelope of Epstein-Barr virus were determined in serum samples
from patients infected by the human immunodeficiency virus (HIV) who belonged to
groups II (n = 26) and IV (n = 32) according to the present Classification System
of HIV infection, as well as in a group of blood donors (n = 52). The geometrical
average titres obtained in the different agents were very high in patients having
HIV infection with respect to the geometrical average titres observed in blood
donors. Patients from group II had titres to the antigen of viral envelope of the
Epstein-Barr virus significantly higher than blood donors. Levels of antibodies
to these agents in patients from group IV were higher than levels obtained in
blood donors. Differences regarding levels of the antigen of viral envelope of
the Epstein-Barr virus were highly significant. These results suggest the
possible relevance of the Epstein-Barr virus infection in the natural history of
AIDS.
PMID- 9768219
TI - [Diagnosis of cytomegalovirus infections in patients with HIV infection.
Comparison of the indirect immunofluorescence and viral isolation techniques].
AB - The technique for the detection of fluorescent early antigen was compared to the
classical method of viral isolation in cells from the human lung. The study was
performed with the use of 85 urine samples from 64 patients presenting with HIV
infection. The technique for the detection of fluorescent early antigens showed a
sensitivity of 91%, an specificity of 97%, and a coincidence of 94% with respect
to viral isolation. The main advantage of the technique for the detection of
fluorescent early antigens with respect to viral isolation is that the former
provides a quicker diagnosis of cytomegalovirus infection within 48-72 hours,
besides being easy to perform.
PMID- 9768220
TI - [Evaluation of an ELISA for the detection of anti-Aspergillus fumigatus
antibodies].
AB - An indirect MicroELISA system for the detection of anti-Aspergillus fumigatus
antibodies using human anti-IgG conjugated to peroxidase was standardized. Serum
samples of two patients having an aspergilloma diagnosed by clinical,
microbiological, and serological criteria were used as positive controls. In
addition, 119 serum samples of blood donors and 216 serum samples of patients
having chronic pneumopathies were also studied. The standardized system may be
used as a diagnostic complement for it is able to discriminate between antibody
levels (IgG) in different clinical forms of aspergillosis and in those
individuals having respiratory diseases which may favour the colonization by this
pathogen.
PMID- 9768221
TI - [Evaluation of an ultramicroELISA system for the diagnosis of rubella].
AB - An indirect Ultramicro ELISA assay, previously standardized in our laboratory,
for detecting antibodies IgG to the rubella virus was assessed in comparison to
the hemagglutination inhibition technique. This assessment allowed to determine
its efficacy in the National System for Epidemiological Surveillance of this
entity. One hundred and ninety serum pairs of clinically suspected cases of
rubella were studied and a high percent of coincidence (99.4%), specificity
(99.4%), and sensitivity (100%) was found between both techniques. In addition,
73 serum samples of blood donors were processed using an indirect microELISA
system (Berhing) which was compared to the Ultramicro ELISA technique for rubella
and it showed a 100% of sensitivity, specificity, and coincidence.
PMID- 9768222
TI - [Establishment of a diploid cell line of human lung (PHuE-1)].
AB - The obtention of a diploid cell line from human lung of great concern for the
virological diagnosis and research is reported. Certain aspects about its
application and characterization are discussed.
PMID- 9768223
TI - [Applying an ultramicroanalytical system to the diagnosis of infectious
diseases].
AB - The multiple applications and advantages of the ultramicro analytical system in
the serodiagnosis of different diseases produced by viruses, bacteria, and
parasites are briefly reported. Also, perspectives in the use of this technology,
not only for the diagnosis, but for the detection of microbial antigens are
pointed out.
PMID- 9768224
TI - [Virologic diagnosis of an outbreak of epidemic hemorrhagic conjunctivitis by an
indirect immunofluorescence technique. Cuba.1989].
AB - The causative agent of an hemorrhagic conjunctivitis outbreak was assessed
through the study of 18 conjunctival exudates using the indirect
immunofluorescence technique and isolation in cell culture of human embryo
fibroblasts. In addition, 395 paired serum samples were studied and Enterovirus
70 was found to be responsible for the outbreak.
PMID- 9768225
TI - [Serologic diagnosis of HIV (1988-1989)].
AB - Determination of antibodies to HIV virus by the ELISA technique was performed in
27,652 serum samples from January 1988 to November 1989. Samples which were
positive twice underwent the Western Blot technique. A 0.41% of positiveness to
the virus was found in 1988 and a 0.34% in 1989. Confirmation of positive cases
by Western Blot was statistically significant in 1989.
PMID- 9768226
TI - [Inhibition of the multiplication of a Coxsackie A9 strain isolated from a
patient with epidemic neuropathy by the interferons alfa and gamma].
AB - We present the results of the in vitro action of alpha and gamma interferons and
of Intacglobin and Igegam against the 47/93/IPK (Coxsackie A9) strain isolated
from the cerebrospinal fluid of a patient with epidemic neuropathy. The in vitro
studies showed that the two interferons inhibited the replication of this agent;
they also showed the presence of antibodies to it in the Intacglobin and Igegam.
The results attained demonstrated that the use of these compounds could be
effective for the treatment of this entity.
PMID- 9768227
TI - [Detection of immunoglobulin A in serum and saliva of patients with hepatitis A].
AB - Specific secretory serum IgA antibodies to the hepatitis A virus from samples
from patients with clinical symptoms compatible to hepatitis A, their contacts,
and healthy subjects were analyzed using an ELISA technique; results were
compared with those of specific serum IgM antibodies to the hepatitis A virus.
The following results were attained in 175 blood samples: coincidence by 98.8%;
sensitivity by 96.8%; and specificity by 100%. Two cases were negative to IGA and
positive to IGM. On comparing the presence of IGA in saliva with the presence of
IGM in blood, coincidence was of 88.1%; sensitivity, of 40.9% and specificity, of
100%. Of the 22 cases with positive IGM in blood, only 9 showed specific IGA
antibodies in the saliva. The 111 cases who had negative IGM in blood were also
negative to IGA. The obtained data suggest that specific serum IGA antibodies to
the hepatitis A virus are an indicator of a recent or occurrent infection due to
this virus and thus it may be considered and alternative for the diagnosis of
this disease.
PMID- 9768228
TI - [Importance of Tarebia granifera in the control of a population of Biomphalaria
peregrina introduced in Cuba].
AB - It was observed that the Tarebia granifera plays a significant role in the
control of a Biomphalaria peregrina population introduced in a permanent water
body. The densities of this planorbid, which had reached high levels, were
notably reduced by two important events: an increase of the water level due to
heavy rains, and the introduction of the competitor, whose effectiveness had been
tested in a different habitat. Knowledge on the ecology and biology of the
competitor and the host in permanent water bodies helped to elaborate the
measures of control which led to the reduction of the host densities while those
of the competitor increased.
PMID- 9768229
TI - [Capacity of the eggs of the larva-eating Rivulus cylindraceus fish, Poey 1860,
for resisting desiccation. Possible use as a bioregulator of mosquito larvae in
temporary reservoirs].
AB - The capacity of the eggs of the Rivulus cylindraceus larvivorous fish to resist
partial desiccation for a certain period of time is described. It was
demonstrated that while the normal development of the eggs last for approximately
14 days, the maximum time of permanence out of the water was of 70 days. Some
characteristics of the R. cylindraceus, which place it among the annual fishes to
be used as biological control agents, are described. The use of R. cylindraceus
as bioregulator in permanent as well as temporary reservoirs is proposed.
PMID- 9768230
TI - [Effect of cypermethrin on some reproductive factors in Culex (C)
quinquefasciatus Say 1823].
AB - An experiment was carried otu with a Culex quinquefasciatus strain with
resistance genes called "Quibu", and with a susceptible strain provided by the
WHO; they were pressured with different lethal doses of cypermetrine. Time
mortality regression lines of the 2 strains were estimated following WHO
methodology and the "Quibu" strain showed tolerance to the insecticide. TL30 and
TL70 were selected to test their effect on fecundity, fertility, sexual index,
and egg eclosion time. A significant reduction in fecundity and fertility was
observed in the "Quibu" strain after it was pressured, no effect was detected on
the sexual index and egg eclosion time in this strain.
PMID- 9768231
TI - [Design of a curve model for the detection of human immunoglobulin G against
herpes simplex virus in ultramicroELISA from a single serum dilution].
AB - The use of a curve model in the application of a ultramicroELISA technique for
the detection of human immunoglobulin G against herpes simplex virus is reported.
Based on end point titration (linear regression) of 100 initial sera, 51 of
these, with r2 > 0.98, were selected, and 4 curve models were elaborated to
relate the natural fluorescence logarithm for 4 dilutions with the previously
determined natural end point titration logarithm. The curve corresponding to the
1:40 (r2 = 0.9645) was selected to evaluate 39 additional serum samples whose
approximate titration was known through the graphic design of the 4 dilutions. An
89% coincidence was found regarding the latter. Divergence of the other 11% was
due to the lack of accuracy of the graphic method in the points near the cutline.
PMID- 9768232
TI - [Anatomy and morphometry of Physa cubensis Pfeiffer, 1839 (Pulmonata: Physidae)
in Cuba].
AB - The anatomic description of Physa cubensis, based on specimens collected in 5
different sites in Cuba, is presented. The anatomic characteristics of the
reproductive system as well as mantle digitations give ground for affirming that
this is a unique species with external morphological variations and thus it
should be kept under the Physa genre. Besides, dispersion diagrams and regression
lines of the length in the width were analyzed in the five sites; the L/A
(length/width) variation quotient was compared using a variance analysis.
Significant differences were observed in the different sites probably due to the
feeding sources of each biotope.
PMID- 9768233
TI - [Outbreaks of hepatitis A in the City of Havana in the year 1991].
AB - Fifty-six outbreaks of hepatitis A infection were studied in City of Havana
between January and September, 1991. In 34 of these, the presence of the
hepatitis A virus (HAV) was confirmed, either by the detection of specific serum
IGM antibodies to the HAV or by the detection of the antigen in the feces of the
subjects under study. Diagnosis was not made in some of the outbreaks due to the
insufficient number of samples sent to the laboratory. Of the 453 blood serum
samples under study, 126 were positive for IGM antibodies to HAV (27.8%): a there
was a good correlation between the presence of this immunoglobulin and the levels
attained by the alanyl aminotransferase enzyme (ALT). Only in 19 feces samples,
of the 263 under study, was the HAV antigen detected, which accounted to 7.2%; it
was demonstrated that this marker is not useful for the diagnosis of an outbreak
of hepatitis A infection.
PMID- 9768234
TI - [Behavior of abiotic factors and rhythm of emission of cercaria of Fasciola
hepatica in Fossaria cubensis in transmission sites].
AB - Sampling of Fossaria cubensis, main host of Fasciola hepatica in Cuba was carried
out in 3 transmission sites. A higher mollusk density was found in dairies
numbers 6 and 9, coinciding with the higher values of total hardness and
carbonate hardness. Ammonium, nitrite, and nitrite ions showed lower values in
dairy number 6. Temperature and pH did not show significant differences in the 3
biotopes. The mollusks of dairy number 6 began to emit cercarias on the 26th day
after being collected; they showed an emission peak at 9 a.m. and an average of
60 cercarias emitted by each mollusk at that time of the day.
PMID- 9768235
TI - [Mechanisms of resistance to organophosphate insecticides, carbamates, and
pyrethroids in populations of Musca domestica L. (Diptera: Muscidae)].
AB - Resistance to organophosphorus insecticides (malathion, chlorpyriphos, pyrimiphos
methyl); carbamates (propoxur); and pyrethroids (permethrin, deltametrine,
cypermetrine, and lambda cialotrine) was studied in field populations of Musca
domestica; results were compared with a susceptible reference strain. The method
of topic application was employed in the bioassays; the synergist effect of the
s,s,s tributyl phosphorotrioate and of the piperonyl butoxide (PB) was also
tested. Biochemical microplate tests were also carried out to determine the
presence of esterase and acetylcholinesterase enzymes in the three populations.
Generalized resistance to malathion (FR = 264.6; 164.0; 154.7) was observed.
PMID- 9768236
TI - [Use of the herbicide diquat for the control of the aquatic plant Pistia
stratiotes and its importance in the control of mosquitoes (Diptera: Culicidae)].
AB - The feasibility of the use of the Diquat herbicide (reglone) in the control of
the Pistia stratiotes aquatic plant is tested. This facilitates the reduction of
mosquito larva densities by the action of natural enemies present in the
ecosystem. The associated fauna is not affected by the employed concentrations of
the herbicide under these conditions.
PMID- 9768237
TI - [Craniofacial dysmorphism in pediatric AIDS. Presentation of a case].
AB - The case of a five-year-old mulatto girl with craniofacial dysmorphism, infected
with AIDS virus, is presented. The girl had ocular hypertelorism; eyes slanted
upwards; increase of the distance between the internal and external canthi;
prominent triangular philtrum; thick lips; prominent forehead; flat nasal bridge;
large parotid glands, which indicate that the infection must have transmitted
during fetal life. These features were not observed in children infected with
AIDS through other ways such as perinatal transmission, blood transfusions and
breastfeeding.
PMID- 9768238
TI - [Bilateral tubo-ovarian abscess caused by Enterobius vermicularis. Presentation
of a case].
AB - We present the case of a 33-year-old patient who had undergone hysterectomy due
to an in situ carcinoma of the uterine cervix; exploratory laparotomy was carried
out for a suspected abscessed pelvic tumor. It was confirmed that the two
Fallopian tubes and ovaries were abscessed and exeresis was carried out. The
anatomicopathological study of these showed granulomas containing gravid female
specimens of the Enterobius vermicularis species.
PMID- 9768239
TI - [Study of the relationship dengue-pregnancy in a group of cuban-mothers].
AB - The current worldwide situation of dengue infection, and particularly in the
American continent, is analyzed taking into account the increasing risk for
infection during pregnancy which exists in endemic areas; the consequences of an
eventual vertical transmission of the virus are practically unknown yet. We
studied 59 women who gave birth to their children between 5 and 9 months after
the "peak phase" of the type 2 dengue virus epidemic which broke out in Cuba in
1981. Sera of the mothers and newborns were studied through various serologic
techniques in order to detect antibodies; in some cases we tried to isolate the
virus, without success, from serum samples taken from the newborns; among these,
we found 4 cases with positive IgM. These newborns showed neither apparent fetal
damage at birth nor further alterations in a follow-up carried out when they
reached 5 years of age. The need of carrying out further studies contributing to
establish an adequate management of pregnant women infected by dengue virus is
discussed.
PMID- 9768240
TI - [Determination of complement-fixing antibodies to respiratory syncytial virus.
Longitudinal study in a population of less than 1 year of age in the City of
Havana].
AB - Respiratory syncytial viruses (RSV) are considered among the most important
agents causing acute respiratory infections in infants below 1 year of age. A 10
year longitudinal study of monosera from children under 15 years was carried out;
1,069 monosera from children under 1 year were studied using the RSV antigen
complement-fixing technique. It was observed that there were short or longer
periods between the peaks of positive sera and when they were compared with
medical care reports, they showed correspondence with increased numbers of
medical care reports. A typical seasonal pattern in the distribution of
antibodies was determined and this corresponded to the month of February,
suggesting that this is probably due to the circulation of the virus and not to
maternal antibodies. The results attained give grounds for considering the
possible circulation of RSV in our country.
PMID- 9768241
TI - [Development and evaluation of an ELISA for the detection of IgM antibodies
against the hepatitis A virus].
AB - We present the results of the normalization of an IgM capture ELISA method for
the diagnosis of type A viral hepatitis with reagents produced in the laboratory
and its comparison with the "Diag-A-Hep" commercial ELISA. The results attained
were: sensibility by 91%; specificity by 100%; and coincidence of the two systems
by 97%. Results are discussed and their relationship with clinical symptoms and
epidemiological characteristics is established. The results attained in 13 serum
samples taken from patients seen during 2 acute viral hepatitis outbreaks agreed
with clinical findings.
PMID- 9768242
TI - [Evaluation of an ELISA for the serologic diagnosis of tuberculosis].
AB - The use of an ELISA method for the serological diagnosis of tuberculosis was
assessed through the study of the presence of circulating IgG antibodies to PPD
in 220 serum samples. An 82% sensibility was determined in 50 serum samples from
patients with pulmonary tuberculosis, and a specificity of 95.33% in 150 serum
samples from apparently healthy subjects. 20 serum samples from patients with
disorders other than tuberculosis were included in the study to determine
possible cross reactions.
PMID- 9768243
TI - [Effectiveness of VA-MENGOC-BC in children from 0 to 5 years of age in Cuba.
First year of observation].
AB - The effectiveness or post-license efficacy of the BC antimeningococcal vaccine
(VA-MENGOC-BC) was assessed 1 year after the end of the immunization campaign in
children aged 0 to 5 years. Occurrence of the disease before and after
intervention is described and effectiveness is estimated following the
recommendations described by Orenstein et al. We used 2 case definitions to
compare results in groups formed following different criteria, according to the
employed diagnostic tests. Two formulas are used to assess efficacy: one,
estimating the rates among vaccinated and non-vaccinated; and the other one,
estimating the ratio of cases per vaccinated population. The increase of the
relative annual decrease of the incidence occurring since 1985--a decrease of 10%
or less--which in 1990 reached 34.6% should be stressed; the ratio of new cases
prevented by the intervention was higher than 75%. Effectiveness or post-license
efficacy was close to 90%, independently from the case definition variant or
formula employed.
PMID- 9768244
TI - Prevalence of Toxocara canis in dogs in the City of Havana.
AB - A study on the prevalence of Toxocara canis in domestic dogs of City of Havana
was carried out for the first time in Cuba. 22 dogs were selected in each
municipality, totalling 330 as the study universe. Dogs' feces samples were
processed through direct examination using Willis' flotation method (1921). The
results attained showed a 17.9% prevalence of Toxocara canis, a high figure
constituting an important risk factor for transmission to humans. This was
influenced by the age of the animals and the hygienic conditions of the houses,
significant factors from the epidemiological point of view. Sex did not play a
significant role.
PMID- 9768245
TI - [Study of the molluscicide activity of different plants on Biomphalaria
havanensis, potential intermediary host of schistosomiasis in Cuba].
AB - Various experimental studies were carried out with plants of the Compositae,
Verbenaceae, Polygonaceae and Agavaceae families to determine their molluscicidal
capacity. Molluscicidal activity on Biomphalaria havanensis was detected in
plants of the Agavaceae family. The plants employed in the experiment were Agave
fourcroydes and Agave franzosinii. Lethal doses were determined. These were: LD50
= 12.45 and LD90 = 22.88 mL/L, for A. fourcroydes and LD50 = 8.78 and LD90 =
15.91 mL/L, for A. franzosinii. No decrease was observed in the effectiveness of
the aquous extracts with the passing of time. Solar radiation did not seem to
effect the molluscicidal activity of the plant extracts.
PMID- 9768246
TI - [Determination of resistance mechanism in Culex quinquefasciatus Say 1823 and its
operational implication in the correct use of insecticides for its control].
AB - Resistance to organophosphorous insecticides such as malathion, chlorpyrihos, and
pyrimiphos-methyl; pyrethroids such as deltametrine and lambda cialotrine; and
the propoxur carbamate was determined in 4 strain of Culex quinquefasciatus of
the Eastern, Central and Western parts of Cuba. The increase of esterase enzymes
was the main mechanism involved in resistance, followed by altered
acetylcholinesterase (AChe). Gene frequencies were high for esterases (1), and
moderate for acetylcholinesterase (0.52) in the four strains under study, as an
average. Bioassays showed resistance to malathion and propoxur. The use of DEF as
esterase inhibitor showed that pyrimiphos-methyl was not affected by this
mechanism of resistance, and chlorpyriphos was slightly affected. After 5 years
of using pyrethroids such as deltametrine and lambda cialotrine, these are still
useful agents for the control of C. quinquefasciatus; the alternate use of these
and pyrimiphos-methyl or chlorpyriphos could prevent the development of
resistance in a short or medium term.
PMID- 9768247
TI - [Application of a mermithid nematode for the control of mosquito larvae in
natural conditions].
AB - Field tests were carried out with the Romanomermis culicivorax nematode (Ross and
Smith, 1976) for the control of 3 mosquito species--Anopheles albimanus
(Wiedeman, 1821): Culex nigripalpus (Theobald, 1901); and Uranotaenia saphirina
(Oster-Sacken, 1868)--in 10 natural reservoirs. The infective nematodes were
disseminated in doses of 1 x 10(3) preparasites/m2 of surface area. Increased
infestation indices were observed with values ranging from 1.2 to 3.4; mortality
percentages fluctuated between 70 and 97% depending on the mosquito species found
in the reservoirs. In those reservoirs containing specimens of the 3 species,
anophelines showed more susceptibility to parasite infection; culicines showed a
lower susceptibility in general. Mosquito larva populations were significantly
reduced in the treated reservoirs.
PMID- 9768248
TI - [Buruli ulcer in the Amansi West district, Ashanti Region, Ghana. The Cuban
experience. I].
AB - A study was made on 105 patients with Buruli ulcer in the Amansie West district,
Ashanti Region, Ghana, representing 37.6% of the registered patients. The
Tontokrom neighborhood showed the highest prevalence: 84 x 1,000 inhabitants.
Predominance of females (54%) was observed. 74.8% did agricultural work and only
3 reported a previous trauma, predominantly with one lesion. Household contacts
were identified. Coverage with the BCG vaccine was low. It is concluded that
there has been a real increase of the prevalence of Buruli in the region during
the last years, especially among children and women. This has become a serious
problem due to its invalidating and irreversible sequelae. Measures of control
are proposed.
PMID- 9768249
TI - [Report pf the first case of lymphogranuloma venereum (LGV) in an HIV
seropositive patient in Cuba].
AB - The most important clinical and epidemiological aspects of the lymphogranuloma
venereum as a sexually-transmitted disease are described. We present a summary of
the clinical history of an HIV-positive patient who presented with a tumoral
lesion in the inguinal region presumptive of lymphogranuloma venereum. The
diagnostic value of the polymerase chain reaction (PCR) technique for the
establishment of an accurate diagnosis is stressed the epidemiological importance
of the report of this sexually-transmitted disease in an HIV-positive patient for
the first time in Cuba is also pointed out. A good response was attained with
Doxycycline.
PMID- 9768250
TI - [Resistance to organophosphate, carbamate, and pyrethroid insecticides in
Blattella germanica (Dictyoptera: Blattellidae) in 2 municipalities of the City
of Havana].
AB - We determined the resistance of 2 Blattella germanica strains collected in 2
municipalities of City of Havana--Playa (P) and Centro Habana (CH)--to six
insecticides: malathion, pyrimiphos-methyl, propoxur, cipermetrine, deltametrine,
and lambda cialotrine. The P strain showed resistance only to deltametrine (FR =
80); the CH strain was susceptible to propoxur and lambda cialotrine and
resistant to malathion (FR = 12), pyrimiphosmethyl (FR = 13), cipermetrine (FR =
16), and deltametrine (FR = 100). Gene frequency of increased esterases and of
the modified acetylcholinesterase was determined in the 2 strains. The values of
increased esterases in the two collected strains were: P = 0.90; and CH = 0.91.
Values of the modified acetylcholinesterase in the two strains were: P = 0.47;
and CH = 0.12.
PMID- 9768251
TI - [Establishment of a subline of C6/36 adapted to growing in a serum-free medium
and its usefulness for studies on the dengue virus].
AB - Using the C6/36 clone of the Aedes albopictus cell line, a derived cell line was
obtained capable of growing in a commercial serum-free medium facilitating this
line to keep its morphologic characteristics and adhesion capacity. The growth
speed rate reduction of the adapted cell line was compensated by its low
maintenance cost. Its usefulness in the multiplication of dengue viruses 1 and 2
was tested; the reported line showed the same susceptibility for the 2 agents
than the original cell line when the indirect fluorescence technique was applied.
PMID- 9768252
TI - [Indirect ultramicroELISA for the detection of total adenovirus antibodies in
human serum].
AB - An indirect ultramicroELISA method was normalized for the detection of total
antibodies to Adenovirus (AD) (UMELISA AD). The optimum concentration of surface
antigen determined was 30 micrograms/mL; serum dilution was of 1:40; and
conjugate dilution, of 1:1,000. The UMELISA AD was compared with the complement
fixing and indirect immunofluorescence techniques. Results showed accordance by
88% and 96.6%, respectively. The method is valid for the screening of antibodies
in seroepidemiological studies as well as for the diagnosis of the infection by
paired serum samples.
PMID- 9768253
TI - [Ampicillin resistance mediated by the R plasmid in strains of Shigella
flexneri].
AB - Forty Shigella flexneri strains isolated from children attended to at the
Children's Hospital of Camaguey during an outbreak of acute diarrheal disease
were studied; the minimal inhibitory concentration of ampicillin was determined.
33 strains (82.5%) were resistant to higher concentrations: 8 to 16
micrograms/mL, and 7 were susceptible to 4 micrograms/mL concentrations.
Resistance plasmid (R) extraction was carried out in all the isolated strains and
a common plasmid was found this plasmid was purified and transferred to
Escherichia coli HE 101. Resistance transmission was tested.
PMID- 9768254
TI - [Hematologic-nutritional study in children predisposed to infection with high
load of Trichuris trichiura].
AB - A coproparasitological survey is carried out in 3 family doctors' home-offices in
City of Havana Province following the Kato-Katz technique (3 samples from each
person); we found 15 children predisposed to high-load infection by Trichuris
trichiura. This group was compared to a group of 20 children infected with a low
parasite load, and to another group of 20 children with no parasite infection. A
study of nutritional anemia was carried out to all of them including: hemoglobin,
hematocrit, ferritin, serum iron, vitamin B12, and serum and erythrocyte folates.
No significant differences were found in the mean values of the hematologic
parameters under study in the various groups, all values being within normal
limits. All the children under study had normal anthropometric-nutritional index
values. Based on the results attained, we suggest that the reported anemia in
individuals infected with a high load of T. trichiura is not only due to parasite
infection; other factors may influence on it, probably a certain concomitant
protein-energy deficiency.
PMID- 9768255
TI - [Study of the seroprevalence of toxocariasis in an infantile population in the
City of Havana].
AB - A serological study to detect antibodies to Toxocara canis in a group of 156
healthy children from City of Havana is reported for the first time in Cuba. An
ELISA method was employed using excretion/secretion antigens obtained in our
laboratory. Data on epidemiological factors surveyed in this group are presented.
Positivity percentage was of 5.2%. Results are discussed.
PMID- 9768256
TI - [Fecundity and embryonal development of Romanomermis culicivorax].
AB - Romanomermis culicivorax (Ross and Smith, 1976) eggs completed the late
preparasite curling phase of their embryo development in an average time of 11
days and at a temperature of 25 +/- 2 degrees C. It was also observed that female
R culicivorax specimens laid 312 eggs in 13 days, when male and female specimens
were placed in a substrate of distilled water with a pH = 4.5.
PMID- 9768257
TI - [Effect of primaquine on the elimination of sexual forms of Plasmodium falciparum
in vivo].
AB - A study was made on 49 patients, carriers of sexual forms of Plasmodium
falciparum, verified through thick smear tests, who received 45 and 90 mg of
primaquine base in different schedules selected at random. None of the employed
schedules proved better than the traditional one of 45 mg base in a unique dose,
although the schedule of 45 mg on the first and third days showed a slight
reduction of the time of elimination of the parasitemia. Thus, further studies
are recommended. No other factors showed an influence on the time of elimination
of the parasitemia.
PMID- 9768258
TI - [Status of insecticide resistance in 4 strains of Musca domestica collected in
animal farms].
AB - Resistance to insecticides made from different chemical compounds were studied in
4 strains of Musca domestica collected from 2 poultry farms and 2 cow farms
following WHO methodology. A high resistance to malathion was observed
(resistance factor values ranging from 102X to 252X), and moderate, to diazinon,
fenthion, dichlorvos, DDT, and propoxur. Resistance to the deltametrine and
permethrin pyreturins was not observed.
PMID- 9768259
TI - [Effect of 3 organophosphates on the reproduction of Culex quinquefasciatus Say
1823].
AB - An experiment was carried out with a Culex quinquefasciatus strain with
resistance genes called "Quibu", this strain was pressured with 3
organophosphorous insecticides: malathion, chlorpyriphos, and pyrimiphos-methyl.
The most toxic for this species was the chlorphyriphos (LC50 = 0.000009 mg/L),
followed by pyrimiphos-methyl (LC50 = 0.00026 mg/L), and malathion (LC50 = 0.0035
mg/L). Larvae surviving the effects of the LC30 and LC70 of the three
insecticides were selected to test their effect on fecundity, fertility and
sexual index. Fecundity was not affected by the employed doses of chlorpyriphos
and pyrimiphos-methyl, while a significant decrease was observed with the LC30
and LC70 of malathion. The employed doses of malathion did not affect fertility
but there was a slight decrease with the LC70 selections of chlorpyriphos and
pyrimiphos-methyl. The proportion of adult females showed a significant increase
with the doses of chlorpyriphos and pyrimiphos-methyl; sexual index was not
affected by malathion.
PMID- 9768260
TI - [A computer program for the geographic distribution of fluvial mollusks of
medical interest in Cuba].
AB - The need to know the distribution of mollusks considered to play an important
medical role in Cuba through a geographic representation motivated us to develop
a software capable of acting as a system for the retrieval of geographic
information in which the requested data would be presented in maps. The system
has been called DMIM and it is a useful tool for malacological studies, and
assessment and planning of programs for the control of intermediate host
mollusks, as well as for teaching purposes.
PMID- 9768261
TI - [Normalization of an ultramicroELISA for the detection of antibodies against
human Parvovirus B19].
AB - An ultramicroELISA (UME) method was normalized for the detection of antibodies to
serum human parvovirus B19. The optimum antigen concentration determined was 400
ng/ml, serum dilution was of 1:100; and the conjugate work dilution was of
1:2,000. 11 paired serum samples were also evaluated and antibodies were
detected. The usefulness of the analyzed system is discussed.
PMID- 9768263
TI - [Biological aspects of Blatella germanica (Dictyoptera: Blattellidae) in
laboratory conditions].
AB - In a study of Blatella germanica (L) 1767 (Dictyoptera: Blattellidae) carried out
in laboratory conditions, 6 nymphal stages were found in a period of 114.71 days,
at 29 +/- 1 degrees C and 80-90% of relative humidity. Times of appearence and
eclosion of every ovipositted ootheca, as well as the offspring average of each
one, were determined. Females ovipositted up to 5 oothecas during their life. The
maximum average of eggs found per ootheca was 29.22. The average longevity of
males was lower that that of females (77.23 and 98.40 days, respectively) (t =
2.21; p < 0.05).
PMID- 9768262
TI - [3 combinations of esterases and their relation with the resistance to
organophosphate, carbamate, and pyrethroid insecticides in Culex quinquefasciatus
Say, 1823 (Diptera: Culicidae) in Cuba].
AB - The possible relationship between different patterns of esterases and the
resistance to various types of insecticides was analyzed by bioassays,
biochemical tests, and electrophoresis carried out in a population of Culex
quinquefasciatus from Camaguey and in three colonies obtained from it by family
selection. The original population was heterogeneous and presented 8 combinations
of esterases in polyacrylamide gel. A3A6B6, B1B6 and B1A6B6 were the most
frequent of them and characterized each selected colony. Every studied colony,
including the parental one, showed different levels of resistance to diverse
insecticides. Only the resistance to propoxur showed less variation. In every
colony it seems to exist a combination of resistance mechanisms; however, the
differences found in tests with DEF synergized insecticides show that the
different bands of zymograms may represent esterases contributing in a different
way to resistance.
PMID- 9768264
TI - [Effect of lethal doses of plants of the Agavaceae family on the cardiac activity
and oviposition of Biophalaria havanensis (Mollusca: Planobidae)].
AB - Work was carried out with lethal doses of 3 agavaceas, Agave legrelliana, Agave
fourcroydes and Agave franzosinii, and it was determined the influences of LD50
and LD90 of agavaceas on the cardiac activity reduction. As a result, it was
found that A. fourcryodes has the aqueous extract influencing the most on the
reduction of heart rate. LD90 of agavaceas also affects the embrionary
development of eggs having between 1 and 7 days of oviposition. The greatest
affectation was found among the first. A. fourcroydes and A. legrelliana,
respectively, influence the most on the reduction of the amount of eggs. The
number of eggs ovipositted by mollucs surviving the application of LD90 from A.
franzosinii is lower, as well as the number of hatched eggs.
PMID- 9768265
TI - [Influence of growth development inhibitors on the reproduction of Musca
domestica (Diptera: Muscidae)].
AB - An experiment with a strain of Musca domestica susceptible to insecticides and
treated with different doses of 2 insects' development inhibitors: Juvenon and S
31183, was carried out. These compounds were added to food supplied to third
stage larvae. On calculating dosage-mortality lines, it was found a greater
biological activity in S-31183. Those surviving DL90 were selected for fecundity
and fertility studies. The following crossings were carried out: treated females
x treated males, treated females x untreated males, untreated females x treated
males, untreated females x untreated males (control group). In both compounds it
was observed a remarkable reduction in the production and eclosion of eggs, on
comparing the first three crossings with the control group. As regards fecundity,
sex influences were not observed, whereas fertility was more affected by treated
females. No differences were found in connection with the survival of all types
of crossings. Morphological affectations are reported in pupae and adults.
PMID- 9768266
TI - [Mass breeding of Romanomermis culicivorax (Nematoda: Mermithidae) in the
tropical conditions of Cuba].
AB - To develop the process of mass production on a large scale of the parasite
nematode Romanomermis culicivorax Ross and Smith, 1976, under the control
tropical conditions of Cuba, it was taken into consideration the standardization
of a certain number of variables, such as: utilization of eggs in the process of
infectation, dosage, types of water, types of substrate, temperature, culture
methods, and storage methods of culture batches. High performances in nematoda
and approximately the same amount of females and males were obtained when
mosquito larvae of the species Culex quinquefasciatus Say, 1823, were exposed to
parasite's infective larvae.
PMID- 9768267
TI - [Meningococcal disease and VA-MENGOC BC in minors less than 1 year of age. Cuba,
1983 to 1991].
AB - A study of the chronological series of mortality due to meningococcal disease in
children under one year old, the group of highest incidence during the last
epidemy in Cuba, was carried out. Data were collected by doing a survey in an
uniform way since 1983 throughout the country. More than 90% of the population
between 3 months and 5 years old were vaccinated with VAMENGOC BC since the end
of 1988 until April, 1990. The behaviour of this disease was studied in order to
identify the influence of this vaccine. It is stressed that the mortality
incidence reached its epidemic achme in 1986 and begins a slow descence which is
accentuated in 1990 and 1991, with an annual relative decrease of 26.1 and 34.9%,
respectively. The highest mortality rate was found in 1984, with a significant
reduction in 1990 (-23.8%) and 1991 (-41.8%), after the culmination of the
vaccination campaign with VA-MENGOC BC. It was detected that morbimortality,
which is lower in children under one month because of the probable protection
provided by maternal antibodies, started to increase until the fifth month of
life, when it is observed a trend towards the reduction of morbidity and
mortality. According to the present immunization chronogram, overall protection
in only attained after the sixth mont of life.
PMID- 9768268
TI - [New solid culture media for growing Borrelia persica and Borrelia microti].
AB - A new solid means for the fast detection of Borrelia persica and Borrelia microti
is described. Generally, culture and isolation of Borrelia takes about 21 days.
The serological test, which is carried out more often, takes less time but it is
associated with false positive reactions relatively high. However, our new solid
means reduces the culture time to 72 hours, allowing to have a fast diagnosis of
the disease caused by Borrelia persica and Borrelia microti, and to start the
early treatment of these patients.
PMID- 9768269
TI - [Validation of a ultramicroELISA for detecting antibodies against hepatitis B
surface antigen].
AB - The results of a validation study of the ultramicroanalitical assay for the
detection of antibodies against the hepatitis B surface antigen (UMELISA anti
HBsAg), which was carried out by comparing the results obtained with the
Hepanostika anti-HBsAg, commercial diagnosis kit are presented. For this purpose,
sera from the clinical assays of the Cuban recombinant vaccine against hepatitis
B were used. With the first sera group (n = 30) it was obtained, 93.1% of
sensitivity, 98.5% of specificity and a concordance of 94.3%. The correlation
coefficient showed a similar trend of the results (p < 0.01) and no significant
differences were found in the average geometrical titre (TPG) between both assays
(p > 0.05). With the second group (n = 100), whose assays were carried out at the
"Pedro Kouri" Institute of Tropical Medicine (PKI) and at the Immunoassay Center
(IAC) simultaneously, it was observed a sensitivity of 96.25% in both centers, a
specificity of 75% at the PKI and of 90% at the IAC, and a coincidence of 92% and
95%, respectively. The correlation coefficient presented similar values and there
were no significant differences between the TPG obtained by the two methods (p >
0.05). The results attained show in general the validity of the new assay and the
feasibility to put it into practice either for following up the infection, or for
carrying out clinical assays of vaccine evaluations.
PMID- 9768270
TI - [Aeromonas hydrophila pneumonia associated with a traffic accident. Report of a
case].
AB - The case of a patient who was driving a car after getting drunk is presented. His
car turned over and he fell into an irrigation canal, and, as a result, he
suffered from an incomplete drowning syndrome. He was admitted in the Intensive
Care Unit with acute inflammatory pneumonia and a strain of Aeromonas hydrophila
was isolated in blood. The patient's evolution was favorable. It is the first
report on a case like this in our country.
PMID- 9768271
TI - [Direct sequencing of an amplified product from a serum sample].
AB - It is reported the nucleotide and amino acidic sequence of a great variability
region in the dengue 2 virus genome, starting from the RNA of the original virus
with no passage in the isolation systems. It is compared with the first strain of
dengue 2 isolated during the 1981 epidemic with 4 passages in lactating mouse.
Results show that the nucleotide sequence of serum and of strain A15 are the
same.
PMID- 9768272
TI - [Anomalous response of antibodies in rash-causing viral infections].
AB - 20 pairs of sera from the National System of Seroepidemiological Surveillance of
the triple viral vaccine received in the laboratory with febrile rash diagnosis
were studied. By using the hemagglutination inhibition test, it was observed an
abnormal answer of antibodies to both rubella and measles through a falling of
the antibody titre in one or both diseases, or in one of them with seroconversion
to the other one. With the aim of defining the existence of a possible polyclonal
activation already described in literature, it was decided to study the antibody
response to family Herpesviridae (HSV, EBV, CMV, VZV). 80% of answer to these
viruses were found. The results are submitted and discussed.
PMID- 9768273
TI - [Evaluation of a Dot ELISA for the detection of a Rotavirus antigen].
AB - An evaluation of a Dot ELISA made by the Center of Genetic Engineering and
Biotechnology for detecting Rotavirus antigen, was carried out. 100 feces samples
were analyzed by this technique and the results were compared with those obtained
with polyacrylamide gel electrophoresis, technique traditionally used in the
Rotavirus diagnosis. It was obtained a high coincidence, specificity and
sensitivity among them.
PMID- 9768276
TI - [Taxonomic study of species of the Mycobacterium genus isolated in Cuba].
AB - 40 strains of the Mycobacterium genus corresponding to 12 species, which were
subjected to 62 microbiological and biochemical tests, were studied. Each one was
considered as a character. As a result of the similitude coefficient and their
grouping, 9 phenomes represented by: Phenome I (Mycobacterium fortuitum), Phenome
II (MAI Complex), Phenome III (Mycobacterium phlei), Phenome IV (Mycobacterium
triviale), Phenome V (Mycobacterium smegmatis), Phenome VI (Mycobacterium
gordonae), Phenome VII (Mycobacterium szulgai), Phenome VIII (MAI Complex), and
Phenome IX (Mycobacterium scrofulaceum), were obtained. The strain identification
work was consistent with grouping from the phenotypic point of view.
PMID- 9768275
TI - [Effects of 3 insecticide formulations in the removal and hatching of oothecae of
Blatella germanica (Dictyoptera: Blattellidae)].
AB - Different insecticide formulations used for the control of German Cockroach,
Blatella germanica (L.) were studied to know their effects on the gravid females
of this species. The insecticides assayed were baygon 20% EC, diazinon 60 EC, and
licon 2.5% EC. Exposure to each insecticide showed an effect on the oothecal drop
(p < 0.001). Gravid females treated with baygon had the highest percent of
oothecae detached (71%); whereas diazinon caused the lowest percent (33.5%).
Doses of baygon, diazinon, and icon used showed that among the oothecas detached
hatching occurred only in 19.01%; 34.2% and 39.11%, respectively. Of the oothecas
retained by treated females, the lowest hatching percent was produced by baygon
(13.79%) compared with diazinon and icon insecticides, which presented the
highest hatching percentages with 39.84 and 47.82, respectively. Therefore, the
effects of insecticides on females bearing oothecas may be considered at the time
of selecting an insecticide to control the German cockroach.
PMID- 9768277
TI - [Report of drug resistance in strains of Mycobacterium tuberculosis isolated from
patients in Iran].
AB - 6,472 clinical samples of patients with tuberculosis suspicion between March,
1993 and March, 1994, were studied. Positive results were obtained in 443
patients; 238 females (53.7%) and 205 males (46.3%). The predominant age group
was that between 30 and 39 years (31.5%). The cutaneous test of sensitivity to
the purified protein derivate (PPD) was positive in 178 patients with a range of
10-14 mm. Abnormal radiological images were found in 222 patients (50.1%). Higher
resistance frequency was detected in Mycobacterium tuberculosis strains among
cases suffering from pulmonary tuberculosis. 42 (9.5%) strains were resistant to
isoniazid and 31 (7.0%) to streptomycin. Resistance to one drug was observed in
25 isolations (5.4%). A few strains (1.3%) were resistant to 3 drugs, and 1 of
them to 5 drugs. Clinical and epidemiological data suggest that resistance to
drugs in tuberculosis is becoming an important problem in the region. The fast
diagnosis of this infection and the use of antibiotics with a reduced spectrum
may enable the control of this form of tuberculosis.
PMID- 9768278
TI - [Purification of the natural 24kd (P24) of the type-1 human immunodeficiency
virus (HIV-1) using immunoaffinity].
AB - The use of systems to detect the presence of 24kd protein as well as the levels
of antibodies to it, is very useful in the follow-up of HIV-1 infected
individuals. To develop these systems it is necessary to have this protein
purified. The present paper describes the purification of p24 starting from the
semipurified viral flattening on saocaharose gradient, using immunoaffinity
chromatography with monoclonal antibodies coupled to Sepharosa 4B activated with
cyanogen bromide. For the characterization of the purified product it was used
polyacrylamide gel electrophoresis with silver staining and
immunoelectrotransference. As a result, it was obtained p24 which can be used for
the development of diagnostic tools and monoclonal antibodies.
PMID- 9768279
TI - [Estimation of IgG Adenovirus antibody titers using a standard curve and an
indirect ultramicroELISA essay].
AB - It was possible to standardize a procedure which combined an indirect microELISA
assay with a standard curve and that allowed to estimate the titre of IgG
antibodies to Adenovirus in samples of human serum, using only one dilution of
these. Based on the end-point titre previously determined for a panel of 117
serum samples, we selected 90 of these samples (r2 = 0.98) to build 4 standard
curves that related the natural logarithm of the fluorescence responses to the
natural logarithm of the end-point titre for a wide range of serum dilutions
(1:40 = 1:320). It was selected the curve corresponding to serum dilution 1:40
(r2 = 0.81), which made possible an optimum utilization of those accessories
designed to handle the volumes in the ultramicro range and, therefore, the
automation of the whole procedure. The results obtained as regards the complement
fixation test (100% of sensitivity and 97.3% of specificity) support the use of
this method in our laboratory as a complementary tool to carry out
seroepidemiological studies on a large scale and with diagnostic ends.
PMID- 9768280
TI - [Surveillance of St. Louis encephalitis, Eastern equine and Western equine in the
province of Ciego de Avila].
AB - Serological studies were carried out using the haemagglutination inhibition and
neutralization tests so as to know the circulation dynamics of some arboviruses
with the use of Western and Eastern equine encephalitis antigens and St Louis
encephalitis antigens in human serum from sound and symptomatic individuals, as
well as from sentinel birds, between 1987 and 1991, and during 1994. 1.7% of the
asymptomatic subjects tested presented neutralizing antibodies to to Eastern
equine and 4.8% to St Louis encephalitis. 16 patients with seroconversion by
haemagglutination inhibition to St Louis virus were detected. Surveillance of
sentinel birds showed that during 1988, 1989, and 1994. St. Louis circulated in
the municipalities of Moron, Bolivia and Chambas; whereas in the latter the
Eastern equine encephalitis circulated in 1988 and 1989. Antibodies to Western
equine encephalitis were detected in sound individuals by haemagglutination
inhibition due seemingly to heterologous antibodies, since there were no
neutralizing antibodies against this virus.
PMID- 9768281
TI - [Genetic relatedness of the dengue 3 virus isolated in the outbreak of dengue
hemorrhagic fever in Nicaragua, 1994].
AB - It is reported the isolation of 2 dengue strains, 3 in samples from Nicaraguan
patients suffering from dengue with hemorrhagic manifestations, which showed the
reintroduction of this serotype in the region after being 17 years out of
circulation. It is also reported the genetic characterization of the isolated
strain, which, according to its classification, belongs to the group of dengue 2
strains isolated in Southeast Asi and which have been associated to hemorrhagic
dengue. These results suggest the origin of this strain.
PMID- 9768282
TI - [Enterovirus meningoencephalitis in the last 5 years].
AB - The results of the study of Enterovirus as viral meningoencephalitis producing
agents, carried out from 1990 to 1994, are described, 546 feces samples, 95
cerebrospinal fluids and 1,058 matched sera were studied and obtained from 1,388
patients clinically diagnosed with this disease. Samples for viral isolation were
inoculated into two different cellular systems. The highest number of isolation
was found in diploid cells from human fibroblast. Antibody determinations were
carried out by a neutralization test (micromethod) with 11 Enterovirus antigens
(Echo 4, 6, 9, 11 and 30; and Coxsackie B1, 2, 3, 4, 5 and 6) and in epidemic
periods with the isolated virus. During the years under study, 2 epidemic
outbreaks took place: on caused by Coxsackie A9 (1990-1991) and the other one by
Echo 30 (1994). A greater positivity to Echo 6 and 11 was found among the matched
sera.
PMID- 9768283
TI - [Purification and proteic characterization of a Cuban strain of the hepatitis A
virus].
AB - The purification and protein characterization of one of the Cuban isolated
strains of hepatitis A virus was carried out. For this, it was necessary to
separate the virus from the infected cell by extraction steps with detergents,
concentration by ultrafiltration and finally, ultracentrifugation in
saccharosoglycerol discontinuous gradient. Protein concentration, as well as the
antigenic activity in the different fractions of the gradient were determined.
For the protein characterization of the microorganism, those fractions with the
greatest specific activity were analyzed by polyacrylamide gel electrophoresis
and by Western blotting. It was shown that the viral material was purified and
concentrated in the last fractions of the gradient. Bands corresponding to the
structural proteins of hepatitis A were observed through electrophoresis and
Western blotting.
PMID- 9768284
TI - [Urethritis caused by serotype B Haemophilus influenzae. Report of a case].
AB - A case of a patient with schistosomiasis haematobium history, from Mozambique, is
presented. This patient was admitted in the Institute of Tropical Medicine for
having urination troubles and purulent urethral secretion. Serotype B Haemophilus
influenzae, biotype i.v. of the urethra, was isolated. The strain was sensitive
to ampicillin, chloramphenicol, ceftraxione, and norfloxacin, and resistant to
tetracycline and erythromycin. The patient got better after receiving treatment
with norfloxacin. A comment is made on the role of this microorganism as a sexual
transmission pathogen.
PMID- 9768285
TI - [ELISA identification of agents causing light cytopathic effect isolated during
the neuropathy outbreak in Cuba, 1991].
AB - Using as a reference the strain 44/93 isolated during the neuropathy epidemic in
1991 and characterized as a producer of a light cytopathic effect (L-CPE), it was
possible the standardization of an ELISA for the fast identification of other
strains with similar effect. The assay consisted in a sandwich-type ELISA where
the conditions selected for each reactive (10 micrograms/mL for the coating
antibody, 1 mg/mL for the antigen, and dilution 1/2,000 for the conjugate)
allowed to have an adequate discrimination between the antigen and the antigen
control for the reference strain used. The evaluation of a panel of reference
viral strains and of other L-CPE producing strains showed a 100% of coincidence
between this method and the isolation in cellular culture. The results obtained
permit us to recommend the use of this assay as a more precise alternative to
identify these agents.
PMID- 9768286
TI - [Subgroups classification of strains of the respiratory syncytial virus isolated
in an outbreak in Ciudad de La Havana].
AB - A high number of acute respiratory diseases was detected among children under one
year admitted in a hospital of Havana City. 25 respiratory syncytial virus
strains were obtained from 93 patients studied. Viral isolations were multiplied
in HEP-2 cells and after observing a cytopathic effect of 80%, they were
classified into subgroups by the indirect immunofluorescence technique, using
anti-protein G antibodies from the respiratory syncytial virus. All the samples
studied were classified within subgroup A. It is the first time a study like this
is conducted in our country, which allowed us to deepen into the viral cause of
these diseases and to know that the subgroup A of the respiratory syncytial virus
circulated during the outbreak.
PMID- 9768287
TI - Gastroduodenal inflammation associated with Helicobacter pylori infection.
Diagnostic and therapeutic implications (a review).
PMID- 9768288
TI - Saprophytic and cycloheximide resistant fungi isolated from golden hamster.
AB - Healthy hair samples from golden hamsters were examined for the presence of
dermatophytes and non-dermatophytes using baiting technique and direct
inoculation. Thirty-four species and 2 varieties attributed to 17 genera were
recovered. Paecilomyces variotii (isolated from 84.4% of the examined hair) and
Aspergillus niger (81.3%) were the more frequent isolates on Sabouraud's dextrose
agar (SDA) without cycloheximide. Our results have clearly demonstrated that the
hair of hamster was free from true dermatophytes. Using the dilution plate method
many fungal species were isolated from cage material (7 genera and 10 species + 1
variety); from faeces (10 genera and 17 species); from standard chow (3 genera
and 6 species) of hamster. P. variotii which was the most frequent fungus in the
preceding 3 substrates was completely absent in the presence of cycloheximide in
SDA. The present study has demonstrated for the first time the isolation of
Trichophyton rubrum from hamster faeces. Also, several saprophytic and
cycloheximide resistant fungi were isolated. In the air of hamster cage
Cladosporium cladosporioides, Penicillium chrysogenum, Alternaria alternata and
Scopulariopsis brevicaulis were the most dominant species on SDA with or without
cycloheximide. Using the agar diffusion method, Aloe sap, onion oil, garlic bulb
extract and aqueous leaf extracts of Andropogon citratus, Euphorbia sp. and Ruta
graveolens were tested for their antifungal activity on 10 fungal species. It was
observed that onion oil exhibited a high inhibitory effect against most of the
tested fungi.
PMID- 9768289
TI - Follow up of clinical, laboratory, and serological findings of adult Hungarian
hospitalized acute hepatitis patients and characteristics of recovery.
AB - Follow-up features of acute viral hepatitis were evaluated of 210 hospitalized
adult patients. HA, HB, HC, and NON A-C H were diagnosed in 68 patients, 84
patients, 22 patients, and 36 patients, respectively. Post-hepatitis syndrome was
shown in about 20.6%, 19%, 45.5%, and 25% of patients with HA, HB, HC, and NON A
C H, respectively. At three months, the recovery was shown in about 61.7%, 69%,
13.6%, and 63.9% of patients with HA, HB, HC, and NON A-C H, respectively.
Factors of sex, age, and severity of acute phase had no effect on the protracted
rate in all types, except in HB. After six months, the disease remained active in
1.5%, 6%, 69%, 8.3% of patients with HA, HB, HC, NON A-C H, respectively. Factors
of sex, age, severity of acute phase had no effect on the chronicity rate in
different types, except HB. It was more significantly more frequent in males,
elderly persons, and mild acute phase in chronic HB cases. Diabetes mellitus was
also significantly more frequent in chronic HB cases. Flat pattern of ALT
elevation was significantly more frequent in chronic HB and NON A-C H cases.
PMID- 9768290
TI - Effect of trace element combination on the immune response of rats treated with
cytostatic drug.
AB - The effect of trace element combination, Beres Drop Plus (BDP) on the immune
response of rats following single treatment with cytostatic drug (5-fluorouracil,
5-FU) was tested. Animals were treated with 5-FU and SRBC simultaneously, but
separately. Rats were pretreated with BDP for 21 days. The body and spleen
weight, furthermore the number of spleen cells and antibody producing cells were
determined. The antibody titres in blood serum were also measured. The immune
system of rats, 5 days following the 5-FU treatment, showed considerable
regeneration. Pretreatment of rats with BDP had a beneficial effect on all
parameters investigated.
PMID- 9768291
TI - Effect of different carbon sources on the production of amylase by Bacillus sp.
MD 124.
AB - An extracellular, thermostable salt tolerant amylase has been obtained from
Bacillus sp. MD 124 which was previously isolated from municipal garbage. Among
the carbon sources used for amylase production, rhamnose, starch, glucose,
lactose, galactose, maltose and sucrose favoured enzyme production whereas
sorbose suppressed the enzyme production. Maximum amount of enzyme (15 unit/ml
culture broth) was produced after 24 h of incubation at 45 degrees C in the
medium containing 0.5% starch, at pH 6.5. The effect of temperature, pH as well
as effect of metal ions on enzyme activity was also studied.
PMID- 9768292
TI - Partial inhibition of amplifications by primers of EHEC genes.
AB - Diagnostic value of multiplex polymerase chain reaction (PCR) was examined by
using three primer pairs, specific for the common conserved region of stx1 and
stx2, eae and an enterohaemolysin A gene (ehxA). The sensitivity in respect of
each amplicon decreased with three exponents comparing to the individual PCR
reactions. These PCR reactions were partially inhibited by the presence of
certain additional primers. This inhibitory effect was template-concentration
dependent, and was partially balanced by usage of increased amount of dNTP. Taq
DNA polymerase in a range of 0.3-1.25 U/reaction did not influence the
inhibition. The same inhibition was detected if the annealing temperature was
changed from 48 degrees C to 57 degrees C. Pairs of EHEC primers inhibited a
Salmonella enteritidis virulence-plasmid specific gene amplification, as well.
Theoretical inhibiting effects were predicted by Primer Premier software but our
observations can be sufficiently explained neither by the competitions between
the specific and aspecific amplifications nor by the inhibition caused by
dimerization of primers.
PMID- 9768293
TI - Fast method to remove UV absorbing agarose gel contamination from DNA samples.
AB - Agarose gel electrophoresis and subsequent purification of DNA bands from the
agarose gel is a widely used molecular biological method. There are different
methods to achieve this goal, however they have different advantages and
disadvantages. One major problem is the presence of different contaminants in the
final sample. We developed a method which is effective in removal of the agarose
contaminants.
PMID- 9768294
TI - Effect of antilymphocyte serum on bacterial translocation in mice.
AB - Following intraperitoneally applied treatment with antilymphocyte serum (ALS) of
immunosuppressive effect no bacterial translocation (BT) was observed in mice.
The ALS treatment applied in combination with other immunosuppressive agents such
as lymphotropic cytostatics as dianhydrogalactitol or chlorpromazine did not
increase the mice's drug sensitivity to the used agents. According to our
results, ALS can be suitable for combined application with other
immunosuppressive agents as it can increase immunosuppression without side
effects such as those induced by bacterial translocation.
PMID- 9768295
TI - The incidence and characteristics of violent men in substance abuse treatment.
AB - Linkage between marital violence and substance abuse has been noted in men
seeking treatment for substance-use disorders. The present study examined (1) the
incidence of family violence in men admitted into substance abuse treatment; (2)
the psychosocial characteristics associated with marital violence; and (3) the
comparability of violent substance abusers to their treatment cohorts. Fifty-nine
men in substance abuse treatment involved in a significant relationship in the
past year were assessed for substance abuse, family violence, psychosocial
functioning, and personality attributes. Fifty-eight percent of men reported at
least one incident of physical familial violence in the past year, while 100% of
the men reported having engaged in psychological abuse in the past year.
Additionally, greater violence was associated with interpersonal insensitivity,
hostile outbursts, and poorer overall functioning independent of substance abuse.
Finally, violent male substance abusers reported significantly more hostility,
suspiciousness, projection of blame, and interpersonal inadequacy than did the
less violent substance abusers. These findings suggest that, in drug-treatment
settings, systematic objective screening for family violence is routinely called
for.
PMID- 9768296
TI - Social skills, expectancies, and drinking in adolescents.
AB - Research in the field of teenage drinking behavior has shown relationships
between both social skills and drinking and alcohol expectancies and drinking.
The present research investigated the comparative power of both of these sets of
variables in predicting teenage drinking behavior, as well as looking at the
contribution of more global cognitive structures. It was hypothesised that
adolescents with high alcohol involvement would be discriminated from those with
low involvement on the basis of social skills, cognitive structures, and alcohol
expectancies. Seven hundred thirty-two adolescents participated in the study.
Results indicated that adolescent alcohol involvement was associated with social
skills deficits, positive alcohol expectancies, and negative cognitive structures
concerning parents and teachers. The results revealed that, although the bulk of
the variance in drinking behavior was explained by the independent effects of
social skills and expectancies, the interaction of the two constructs explained
an additional and significant proportion of the variance. Implications for
preventive and treatment programs are discussed.
PMID- 9768297
TI - Habit control expectancy for drinking, smoking, and eating.
AB - Habit-specific locus of control measures for drinking, smoking, and eating were
compared to Rotter's general measure to evaluate the relationship between
cognitive expectancy and substance use. For both smoking and eating, individuals
who reported being addicted were significantly more external on the habit
specific expectancy measures. Measures of use, tolerance, and risk covaried more
closely with the habit-specific scales than with the general scale. For eating
behavior, the habit-specific scale and the compulsive eating measure were
different only for individuals with a history of being overweight. The habit
specific expectancy measures were more closely related to indices of use and
addiction than the general locus of control measure and should have greater
utility for research and intervention.
PMID- 9768298
TI - The role of weight concern and self-efficacy in smoking cessation and weight gain
among smokers in a clinic-based cessation program.
AB - Although the majority of smokers are concerned about postcessation weight gain,
few studies have investigated the prospective relationship between weight concern
and smoking and weight outcomes, or a mechanism by which concern is related to
these outcomes. We investigated the prospective role of smoking-specific weight
concern in smoking cessation and weight gain among participants in a smoking
cessation clinic, and we hypothesized that domain-specific self-efficacy would be
a mediator of these relationships. While weight concern did not prospectively
predict smoking status, increased weight concern predicted weight gain at the end
of treatment and at 3-month follow-up. Self-efficacy for preventing postcessation
weight gain mediated this relationship; lower levels were related to a greater
likelihood of weight gain. Weight gain was found to be associated with subsequent
relapse among abstainers. Implications and treatment recommendations are
discussed.
PMID- 9768299
TI - Frequent childhood geographic relocation: its impact on drug use initiation and
the development of alcohol and other drug-related problems among adolescents and
young adults.
AB - Early geographic relocation has been implicated as an important correlate of
psychopathology, learning difficulties, and behavioural problems among child and
adolescent populations, yet systematic studies of the potential influence of
relocation on youthful drug use have not been conducted. This study explored the
relationship between number of geographic moves before the age of 16 and the
timing of onset of drug use and progression to drug-related problems. Data were
obtained from 3,700 young adults aged 18 to 35 years participating in the 1990
1991 Ontario Mental Health Supplement, a large random probability survey of the
residents of the Province of Ontario, Canada. Holding constant potential
confounding factors, results showed highly significant positive relationships
between moving and early initiation of illicit drugs including marijuana,
hallucinogens, crack/cocaine, and illicit use of prescribed drugs. Among
marijuana users, moving was also associated with a hastening of time to marijuana
related problems. Relationships between moving and measures of alcohol
use/problems (onset of first drink, onset of any alcohol-related problem) were
either weak or nonsignificant. Important sex differences were found, with
statistically significant relationships between moving and early drug use
initiation and progression occurring primarily among males. Future research is
required to test for possible mediating mechanisms linking relocation with drug
use as well as moderating influences. Efforts should also focus on finding out
why drug use appears to be a more common response to relocation among boys.
PMID- 9768300
TI - Effects of maternal cigarette smoking during pregnancy on long-term physical and
cognitive parameters of child development.
AB - The negative impact of maternal cigarette smoking during pregnancy on the growth
and development of the foetus has been well documented. However, the long-term
effects of the subsequent cognitive and physical development of the child are
less clearly understood. This article presents a critical review of the
literature on this topic. The review shows that the effects of prenatal exposure
to smoking on children's physical development are mediated by a dose-response
relationship. Although the observed effects are long term, they are small and may
have no major functional importance. The evidence on the long-term consequences
of intellectual function is still unclear. One reason is that very few studies
have looked at the long-term consequences of maternal smoking on both physical
and cognitive development. More effort is needed to investigate this important
issue.
PMID- 9768301
TI - Application of the transtheoretical model of behavior change for obesity in
Mexican American women.
AB - The prevalence, consequences, and resistance to treatment of obesity make it one
of the most difficult psychological and medical problems in society today. The
incidence of obesity is greater in Mexican Americans than in Caucasians. The
purpose of this study was to apply the Transtheoretical Model of Behavior Change
on a sample of Mexican American women in weight-loss study. Questionnaires
assessing the stages and processes of change were shortened, translated, and
administered to subjects. Cluster analyses were conducted to determine the stage
of change profiles, with five distinct profiles emerging. These profiles are
consistent with those reported in previous research on smoking, psychotherapy,
alcoholism, and overeating. Relationships among stages, processes, and profiles
of change were examined and found to be consistent with previous research. This
study supports the use of the Transtheoretical Model with Mexican American women
who were enrolled in a behaviorally oriented weight-loss program. Results of the
study are limited owing to a small sample size; however, it does provide a
foundation to incorporate Hispanic populations in future studies pertaining to
stages and processes of behavior change.
PMID- 9768302
TI - Hazelden's model of treatment and its outcome.
AB - Although the Minnesota Model of treatment for alcohol and drug addiction is a
common treatment approach, there are few published reports of its effectiveness.
This study describes the Minnesota Model treatment approach as practiced at
Hazelden, a private residential alcohol and drug abuse treatment center located
in Center City, Minnesota (a founding program of the Minnesota Model) and
presents recent outcome results from this program. This study includes 1,083 male
and female clients admitted to Hazelden for treatment of a psychoactive substance
use disorder between 1989 and 1991. The outcome study is a one group
pretest/posttest design. Data collection occurred at admission to treatment and
at 1-month, 6-month, and 12-month posttreatment. At 1-year follow-up, 53%
reported that they remained abstinent during the year following treatment and an
additional 35% had reduced their alcohol and drug use. These results are similar
to those reported by other private treatment programs. The Minnesota Model has
consistently yielded satisfactory outcome results, and future research needs to
focus on the therapeutic process of this common treatment approach.
PMID- 9768303
TI - A prototype analysis of psychological situations through the lens of alcohol
expectancies and gender.
AB - The psychological situation, with significant origins in cognitive and
personality psychology, consists of the meaningful environment encountered by an
individual at a given time. In the present study, participants generated the
characteristics (environmental, emotional, social, and cognitive) that they found
as characteristic of "dating," "blind dating," and "drinking with friends"
situations. Participants also completed a brief form of the Alcohol Expectancy
Questionnaire (Brown, Goldman, Inn, & Anderson, 1980). Results indicate that
women were more likely to characterize "drinking with friends" with negative
descriptors; women were also likely to have more overlap than men in their
schemas for "dating" and "drinking with friends." Participants with stronger
alcohol expectancies also displayed more overlap in their schemas for "dating"
and "drinking with friends" than did those with weaker expectancies. Results are
discussed in terms of differing drinking experiences for men and women, and on
the relationship between situational cues and expectancies.
PMID- 9768304
TI - Regret, substance abuse, and readiness to change in a dually diagnosed sample.
AB - The transtheoretical stages of change model posits that increased readiness to
change is associated with greater awareness of the negative consequences of
substance use. Experiencing regrets implies a greater awareness of these
consequences. Eighty dually diagnosed patients completed a 22-item Measure of
Substance-Related Regret (MSR) that assessed the intensity, type, idiographic
importance of, and emotions associated with regrets related to substance use and
the Brief Readiness to Change Questionnaire. The MSR yielded a global measure of
regret that accounted for statistically significant amounts of variance in total
readiness-to-change scores (R2 = .30). Global scores also predicted
precontemplation and contemplation stage scores, whereas total fear scores
associated with regrets predicted action scores. Regret seems to play a complex
yet important role in the decision to change substance abuse.
PMID- 9768305
TI - Predictors of participation in a smoking cessation intervention group among low
income women.
AB - The predictors of participation in a smoking cessation group among low-income
women were examined. Fifty smokers were recruited from a Midwestern community
primary care setting serving an uninsured, underinsured, and Medicaid population.
Participants completed a questionnaire before the intervention, and eleven women
chose to participate in the 6-week sessions. There were few differences between
the control group (nonparticipants) and the intervention group. The intervention
group had significantly higher intention-to-quit scores. Logistic regression
analysis was used to predict group membership with age, self-efficacy, optimism,
social support, nicotine dependence, intention-to-quit, and other smokers in the
home as the predictor variables. The only two significant predictors of
participation in the cessation intervention were self-efficacy and intention-to
quit smoking. The higher the intention-to-quit score and the lower the self
efficacy score (the belief that one can be successful in not smoking); the more
likely these women were to participate in the group intervention. Results are
discussed in terms of their clinical relevance as well as future research in the
area.
PMID- 9768306
TI - Predicting drug use: application of behavioral theories of choice.
AB - The current study sought to test the utility of Herrnstein's (1970) matching law
in predicting drug use occurring in the natural environment. Participants were
206 college students. Behavioral allocation was measured across two concurrently
available sets of activities: those engaged in while using or under the influence
of drugs and/or alcohol (drug related) and those engaged in when drug free.
Results from regression analyses indicate that predictions of drug use are
improved with the addition of reinforcement received from drug-free activities,
which enters the model with a negative coefficient value. The addition of a
reinforcement ratio, based on matching law equations, also accounted for unique
variance. Results demonstrate the utility of applying behavioral theories of
choice to drug use and highlight the importance of viewing behaviors within their
broader environmental context.
PMID- 9768307
TI - Creativity of undergraduates with and without family history of alcohol and other
drug problems.
AB - Noble, Runco, and Ozkaragoz (1993) provided evidence that alcoholics' children
differ negatively from recovering alcoholics' and nonalcoholics' children in
terms of personality characteristics related to creativity. They also found that
divergent thinking test scores among the three groups of children are similar,
yet the possibility exists that offspring compensate for the personality deficits
and maintain productively creative lives in spite of the negative influence of
parental substance use. This study investigated the impact of parental substance
abuse problems on 163 undergraduates' creative achievement. With current alcohol
consumption as a covariate, analysis of covariance results suggest that parental
alcohol and drug problems do not have an appreciable effect on students' creative
achievement, although marginally significant interaction of gender and family
history provides limited evidence that gender may influence the impact of
parental substance abuse on creativity. Because the true effects of parental
substance abuse may not be felt for several years, future research should
investigate these issues with older offspring.
PMID- 9768308
TI - Psychoanalysis and the model of homosexuality as psychopathology: a historical
overview.
PMID- 9768309
TI - Elma Laurvik, Ferenczi's stepdaughter.
PMID- 9768310
TI - Horney, Zen, and the real self.
PMID- 9768311
TI - Self-esteem: the past of an illusion.
PMID- 9768312
TI - Induced recall of film music: an overlooked mirror of transference
countertransference interactions.
PMID- 9768313
TI - Lacan's theory of self and the story of the last cookie.
PMID- 9768314
TI - Effect of sinus surgery on visual disturbance caused by spheno-ethmoid mucoceles.
AB - Fifteen patients suffering from visual disturbance of varying degrees caused by a
mucocele of the posterior ethmoid and/or sphenoid sinuses underwent
marsupialization of a mucocele into the nasal cavity. Five of the eight patients
with severe visual loss worse than 20/200 showed recovery of measurable vision.
Two of these five were operated on within 24 hours after the onset of visual loss
and showed marked recovery to 20/25 and 20/15. The other seven patients who had
relatively mild visual disturbance experienced improvement of visual acuity or
remission of subjective complaints such as blurred vision post-operatively.
During operation partial bony defect was found in the optic canal in 12 patients
and in the skull base in 12 patients. A good understanding of this disease by
ophthalmologists and otolaryngologists is essential for early diagnosis and
prompt surgical treatment to avoid permanent visual dysfunction and operative
sequelae.
PMID- 9768315
TI - Myospherulosis of the upper eyelid as a complication of endoscopic sinus surgery.
AB - Myospherulosis is a chronic inflammatory reaction to the mixture of red blood
cells and petroleum based ointments. A literature review does not reveal any
cases involving ophthalmic manifestations. We present the first reported case of
a patient experiencing recurrent eyelid inflammation from myospherulosis after
endoscopic sinus surgery. The pathophysiology and management of myospherulosis
are discussed.
PMID- 9768316
TI - Combined endoscopic intranasal and external frontal sinusotomy.
AB - We review our experience treating patients with medically refractory frontal
sinusitis that could not be relieved with endoscopic intranasal surgery alone.
Fourteen combined external and intranasal endoscopic frontal sinusotomies were
performed on a consecutive sample of 11 patients presenting over a 38-month
period of study. Postoperative results were classified as cured, improved,
unchanged, or worse, based on patient symptoms and physical findings. At a mean
postoperative follow-up of 19 months (range 4-36), 100% of these patients had
benefited from this technique (7 cured, 4 improved, 0 unchanged, 0 worse). There
were no major complications and natural sinus physiology was preserved. We
conclude that a combined external and endoscopic intranasal frontal sinusotomy is
an effective alternative to frontal sinus obliteration.
PMID- 9768317
TI - Intranasal anatomic variations in pediatric sinusitis.
PMID- 9768318
TI - Recirculation of mucus as a cause of persistent sinusitis.
AB - Recirculation of mucus between adjacent openings into the maxillary antrum is a
relatively common cause of persistent sinusitis in either the pre- or
postsurgical patient. It is particularly common after FESS when the new middle
meatal antrostomy has been sited too far posteriorly behind an existing natural
maxillary ostium. The condition is easily diagnosed with the nasal endoscope and
the surgical remedy of joining the separate openings into one larger antrostomy
is readily carried out under local anesthesia in the rhinologist's office.
PMID- 9768319
TI - A comparison of two methods for determining nasal irritant sensitivity.
AB - Nasal irritation and irritant-induced reflexes (rhinorrhea and congestion) are
prominent symptoms associated with indoor and ambient air pollution, and marked
heterogeneity in individual sensitivity has been suggested. Nevertheless, there
is currently no generally accepted functional index of nasal irritant sensitivity
available for clinical use. To address this issue, we compared two objective
measures of nasal irritant sensitivity: a CO2 detection task, and CO2-induced
transient disruption of respiratory pattern (pulsed CO2 acting as an odorless
irritant). Using a respiratory flow thermocouple to produce a continuous
recording of respiratory pattern, we challenged 20 normal adult volunteers (13
males and 7 females, average age 39.4 years) with brief (approximately 3 second)
pulses of the odorless irritant carbon dioxide. Increasing levels of CO2 (10-70%,
vol/vol), paired with filtered air in random order, were presented unilaterally
by nasal cannula of fixed geometry, synchronized with the inspiratory phase of
the respiratory cycle. All subjects yielded CO2 detection thresholds, whereas
within the constraints of the testing method (subjective irritation rating < or =
"very strong"), only 13 of 20 subjects (65%) exhibited transient disruption of
their breathing pattern. Further, although decreased respiratory volume
(indirectly measured) appeared to be a common feature, several distinct patterns
of respiratory alteration were observed, rendering objective scoring more
difficult. Finally, some subjects showed CO2-induced respiratory disruption
intermittently from trial to trial, implying that rapid adaptation occurs.
Determination of the CO2 detection threshold therefore appears to be the more
objective and consistently applicable endpoint for determining individual nasal
irritant sensitivity.
PMID- 9768320
TI - Acoustic rhinometric assessment of the nasal valve.
AB - The aims of this study are to assess nasal valve cross-sectional areas in healthy
noses and in patients with nasal obstruction after rhinoplasty and to evaluate
the effect of an external nasal dilator on both healthy and obstructive nasal
valves. Subjects consisted of (i) volunteers with no nasal symptoms, nasal
cavities unremarkable to rhinoscopy and normal nasal resistance and (ii) patients
referred to our clinic complaining of postrhinoplasty nasal obstruction. All
subjects were tested before and after topical decongestion of the nasal mucosa
and with an external nasal dilator. In 79 untreated healthy nasal cavities the
nasal valve area showed two constrictions: the proximal constriction averaged
0.78 cm2 cross-section and was situated 1.18 cm from the nostril, the distal
constriction averaged 0.70 cm2 cross-section at 2.86 cm from the nostril. Mucosal
decongestion increased cross-sectional area of the distal constriction
significantly (p < 0.0001) but not the proximal. External dilation increased
cross-sectional area of both constrictions significantly (p < 0.0001). In 26 post
rhinoplasty obstructed nasal cavities, only a single constriction was detected,
averaging 0.34 cm2 cross-section at 2.55 cm from the nostril and 0.4 cm2 at 2.46
cm from the nostril, before and after mucosal decongestion respectively. External
dilation increased the minimum cross-sectional area to 0.64 cm2 in these nasal
cavities (p < 0.0001). We conclude that the nasal valve area in patients with
postrhinoplasty nasal obstruction is significantly smaller than in healthy nasal
cavities as shown by acoustic rhinometry. Acoustic rhinometry objectively
determines the structural and mucovascular components of the nasal valve area and
external dilation is an effective therapeutical approach in the management of
nasal valve obstruction.
PMID- 9768321
TI - Magnetic resonance cisternography and thin coronal computerized tomography in the
evaluation of cerebrospinal fluid rhinorrhea.
AB - In recent years cerebrospinal fluid (CSF) rhinorrhea has been managed
successfully with transnasal endoscopic techniques. The most important and often
most difficult step is the precise localization of the fistula. Computerized
tomographic and radionuclide cisternography are two commonly used techniques for
preoperative identification of the CSF fistula when it cannot be seen clearly
with nasal endoscopy. Each of these requires a lumbar puncture, and the
intrathecal placement of contrast material has been associated with transient
neurotoxicities. Magnetic resonance cisternography (MRC) is a noncontrast study
that does not require a lumbar puncture and has been used recently in the
diagnosis of spontaneous and traumatic CSF leaks. Magnetic resonance
cisternography utilizes a fast spin-echo sequence with fat suppression and video
image reversal that highlights CSF. This allows precise localization of the
fistula in both coronal and sagittal planes. Thin section coronal computed
tomography (TCCT) is another noninvasive technique that can be helpful in
localizing CSF leaks. The technique of MRC and TCCT and the results of 16 CSF
leaks in 15 patients are reported. There was good correlation between MRC, TCCT,
and intraoperative findings. Magnetic resonance cisternography and thin coronal
computerized tomography appear to be accurate and complementary, noninvasive
radiographic studies that should be considered in the evaluation CSF rhinorrhea.
PMID- 9768322
TI - Objective assessment of the breathe-right device during exercise in adult males.
AB - In order to improve nasal breathing during competition, many athletes recently
have been wearing a spring-loaded, external nasal dilator referred to as the
Breathe-Right device (BRD). Although there are many subjective claims that this
device improves breathing during exercise, there are currently no controlled
studies documenting its efficacy. To determine objectively whether the device
improves the nasal airway, 20 subjects (10 Caucasian and 10 African-American)
were studied during rest and after 15 minutes of exercise using anterior
rhinomanometry and acoustic rhinometry to measure changes in airway resistance
and minimal cross-sectional area, respectively. We found that the BRD exerts its
main effect in the region of the nasal valve improving the airway an overall 21%
in our group of subjects. This anatomic improvement in nasal airway resulted in
an overall 27% reduction in nasal resistance in the Caucasian group. However, in
the African-American group, a wider range of resistance changes was observed with
application of the BRD with significant improvement in nasal resistance in some
subjects but paradoxical worsening in others. In the African-American group as a
whole, no significant change in nasal resistance occurred with application of the
BRD. These measured differences are likely due to variations in nasal anatomy
that exist not only between races but also between individuals within a given
race. In addition, this study confirms the well known decongestant effects of
exercise providing anatomic data with acoustic rhinometry not previously
documented in the literature. Overall improvement in nasal airway seen with
application of the BRD occurred independent of these exercise-related
decongestant effects.
PMID- 9768323
TI - Effects of the Breathe Right nasal strips on nasal ventilation.
AB - The Breathe Right nasal strips are more and more commonly used, mainly by
athletes, who hope to enhance their physical performance in competition and
training. The effect of the device in such situations is uncertain and perhaps
somewhat controversial. To investigate the effects of the nasal strips on nasal
ventilation, 20 caucasian individuals were objectively assessed using anterior
rhinomanometry and acoustic rhinometry. The results showed a significant increase
in all subjects of transnasal airflow and in the average cross-sectional area of
the nasal cavity that quantifies objectively the subjective impression of
improved nasal breathing. In such patients where an improvement in nasal
ventilation is desired, the use of the Breathe Right nasal strips seems to offer
a beneficial treatment.
PMID- 9768325
TI - DNA diagnosis of cystic fibrosis.
PMID- 9768324
TI - Insulin resistance.
PMID- 9768326
TI - Multiplex genotyping for cystic fibrosis from filter paper blood spots.
AB - Cystic fibrosis is a common disease of the Caucasian population and is associated
with significant early mortality. We present a simple and rapid method for cystic
fibrosis genotyping from filter paper blood spots, using a currently available
commercial genotyping kit. Using multiplex technology, genotype information on
the four most common UK mutations can easily be obtained within a single working
day. Used in conjunction with current immunoreactive typsinogen screening
protocols, blood spot genotyping offers a method of hastening the diagnosis, and
thus treatment, of cystic fibrosis.
PMID- 9768327
TI - Plasma antioxidants: evidence for a protective role against reactive oxygen
species following cardiac surgery.
AB - Total plasma antioxidant status (TPAS), lipid peroxide concentration (LPX) and
cardiac troponin T (cTnT) were measured in 24 patients undergoing coronary artery
bypass grafting (CABG) with cardiopulmonary bypass (CPB). Samples were obtained
preoperatively and at 1.5 h, 6 h, 24 h and 72 h after CPB. The absolute TPAS
values were significantly lower at 1.5 h, 6 h, 24 h and 72 h after CPB than were
preoperative values (P < 0.05). The LPX concentration was significantly elevated
at 1.5 h after CPB (P < 0.05). Cardiac troponin T concentrations were
significantly elevated at all time points postoperatively (P < 0.05).
Preoperative TPAS values were significantly correlated with the magnitude of fall
in TPAS at 1.5 h (P < 0.05). The greater the fall in TPAS between 0 and 1.5 h,
the less LPX was formed between 0 and 1.5 h. The LPX at 1.5 h displayed a
significant correlation with cTnT release from myocardial myocytes (P < 0.05).
These data provide evidence for the first time that the consumption of
antioxidants during CABG surgery with CPB protects against the production of
reactive oxygen species and subsequent myocyte necrosis. Furthermore, the
availability of protective antioxidants is dependent upon preoperative TPAS.
PMID- 9768328
TI - Multianalyte serum analysis using mid-infrared spectroscopy.
AB - This study assesses the potential for using mid-infrared (mid-IR) spectroscopy of
dried serum films as the basis for the simultaneous quantitation of eight serum
analytes: total protein, albumin, triglycerides, cholesterol, glucose, urea,
creatinine and uric acid. Infrared transmission spectra were acquired for 300
serum samples, each analysed independently using accepted reference clinical
chemical methods. Quantitation methods were based upon the infrared spectra and
reference analyses for 200 specimens, and the models validated using the
remaining 100 samples. Standard errors in the IR-predicted analyte levels (Sy/x)
were 2.8 g/L (total protein), 2.2 g/L (albumin), 0.23 mmol/L (triglycerides),
0.28 mmol/L (cholesterol), 0.41 mmol/L (glucose) and 1.1 mmol/L for urea, with
correlation coefficients (IR vs reference analyses) of 0.95 or better. The IR
method emerged to be less suited for creatinine (Sy/x = mumol/L) and uric acid
(Sy/x = 140 mumol/L) due to the relatively low concentrations typical of these
analytes.
PMID- 9768329
TI - Determination of serum physiological concentration of methylmalonic acid by gas
chromatography-mass spectrometry with selected ion monitoring.
AB - We developed a sensitive assay for the rapid determination of serum methylmalonic
acid concentration using capillary gas chromatography-mass spectrometry (GC/MS)
with selected ion monitoring and a simple solid-phase extraction. The assay was
linear up to 10,000 nmol/L and had a detection limit < 50 nmol/L, average
recovery of 98% and between-day coefficient of variation at concentrations of 570
and 2206 nmol/L of 7.7% and 5.4%, respectively (n = 25). Comparison with another
validated GC/MS method using sera with a wide range of methylmalonic acid
concentrations (94-2020 nmol/L) revealed a slope and intercept of 0.97 and 17
nmol/L, respectively (n = 38). Methylmalonic acid concentrations determined by
this assay in a group of apparently healthy individuals ranged from 64-331 nmol/L
(n = 81). We conclude that the method is ideally suited for the determination of
methylmalonic acid at physiological concentrations in both clinical and research
laboratories.
PMID- 9768331
TI - Distribution and expression of adrenomedullin in human gastrointestinal tissue.
AB - Adrenomedullin (AM) is a biologically active peptide recently isolated from
phaeochromocytoma. We report here the distribution and characterization of
immunoreactive AM and gene expression of AM in human gastrointestinal tissue.
Using a sensitive radioimmunoassay system for the peptide, immunoreactive human
AM was detected in the stomach, duodenum, jejunum, ileum and colon. The AM
concentration of these tissues was about 0.4-0.8 pmol/g wet tissue. Reverse phase
and gel filtration high-performance liquid chromatographies showed that most of
the immunoreactive AM in stomach and jejunum was identical to authentic human AM.
By northern blot analysis, human AM mRNA was found to be expressed ubiquitously
in the human gastrointestinal tissues. Furthermore, an immunohistochemical study
revealed that immunoreactive AM cells were present in the gastrointestinal
glands. These results suggest that AM may play some role as a gastrointestinal
hormone.
PMID- 9768330
TI - Effects of sex steroid hormones on corticosteroid-binding globulin gene
expression in human endometrial cancer cell line Ishikawa.
AB - The effect of progestins on intracellular corticosteroid-binding globulin (CBG)
mRNA expression in an endometrial cancer cell line (Ishikawa) was examined in an
attempt to understand the biological effects of high-dose progestins in the
treatment of well-differentiated uterine endometrial cancers. Oestradiol-17 beta
(E2) significantly increased CBG mRNA expression in a dose-dependent manner,
while a high dose of progesterone with or without E2 suppressed it significantly.
Furthermore, a high dose of progesterone or medroxyprogesterone acetate (MPA)
suppressed CBG mRNA expression to a greater degree than did chlormadinone acetate
or 17 alpha-hydroxyprogesterone caproate with or without E2. These findings
suggest that the effects of high-dose progestins on cancer cells may be mediated
via suppression of intracellular CBG.
PMID- 9768332
TI - Sensitive enzyme immunoassay for anti-beta-lactoglobulin IgG in serum.
AB - A sensitive enzyme immunoassay for anti-beta-lactoglobulin immunoglobulin G (IgG)
in serum is described. Serum containing anti-beta-lactoglobulin IgG was reacted
simultaneously with 2,4-dinitrophenyl-bovine serum albumin-beta-lactoglobulin
conjugate and beta-lactoglobulin-peroxidase conjugate. The complex formed from
the three components was trapped onto polystyrene balls coated with anti-2,4
dinitrophenyl group IgG, eluted with epsilon N-2,4-dinitrophenyl-L-lysine and
transferred to polystyrene balls coated with anti-human IgG.gamma-chain IgG.
Bound peroxidase activity was determined by fluorometry. This enzyme immunoassay
was 100- to 1000-fold more sensitive and more reliable than the enzyme-linked
immunosorbent assay (ELISA). Anti-beta-lactoglobulin IgG was detected in 91% of
healthy subjects using this method.
PMID- 9768333
TI - Evolution of an inhibin A ELISA method: implications for Down's syndrome
screening.
AB - The development of a sensitive and specific enzyme-linked immunoassay (ELISA) for
inhibin A stimulated the observation that inhibin A was a useful prenatal marker
of Down's syndrome. Modifications of that ELISA, in terms of preassay sample
treatment, detection methods and standard preparation, were subsequently
introduced to improve assay performance and reduce costs. These modified formats
have been validated and reported. We describe the modifications in detail,
explaining the rationale for each, and report the results of a study directly
comparing the various ELISA formats in terms of assay performance when applied to
clinical samples and ability to differentiate between normal and Down's syndrome
pregnancies. A format involving sample pretreatment with sodium dodecylsulphate
at 100 degrees C was found to give better assay performance and a modest
improvement in discrimination between Down's syndrome samples and controls, and
we recommend this format for use by other investigators.
PMID- 9768335
TI - Evaluation of a latex-enhanced immunoturbidimetric assay for measuring low
concentrations of C-reactive protein.
PMID- 9768334
TI - Automated fluorimetric determination of cellular cholesterol.
AB - We developed a completely automated fluorimetric method for the determination of
cellular cholesterol, consisting of enzymatic hydrolysis of cholesteryl ester to
free cholesterol and enzymatic oxidation of free cholesterol in the presence of
an indicator substrate to produce a fluorescent product. For control preparations
of monocytes, the mean detection limit was 2.57 mumol/5 x 10(5) cells and the
mean within-batch coefficients of variation were 9.30, 6.00 and 3.73% at mean
cholesterol concentrations of 1.94, 9.05 and 12.49 mumol/5 x 10(5) cells,
respectively. The results correlated well with those obtained by gas-liquid
chromatography.
PMID- 9768336
TI - Haemochromatosis case detection by genetic testing: a new era.
PMID- 9768337
TI - Thrombocytopenia and giant platelets without major haemorrhagic complications in
a pregnant patient.
PMID- 9768338
TI - Wilson's disease: gall stone copper following liver transplantation.
PMID- 9768339
TI - CSF spectrophotometry and subarachnoid haemorrhage.
PMID- 9768340
TI - What is the role of CSF spectrophotometry in the diagnosis of subarachnoid
haemorrhage?
PMID- 9768341
TI - Interference in pancreolauryl test.
PMID- 9768342
TI - Addition of further blood to the Boehringer Advantage blood glucose meter.
PMID- 9768343
TI - The role of cytokines in the normal and neoplastic pituitary.
PMID- 9768344
TI - The surgical treatment of lung metastases: an update.
PMID- 9768345
TI - Use of L-asparaginase in childhood ALL.
AB - Owing to the high efficacy of L-asparaginase in the treatment of acute lymphatic
leukaemia the enzyme was introduced into the chemotherapy schedules for remission
induction of this disease shortly after results of large-scale clinical trials
had become available. Since asparaginase monotherapy was associated with a high
response rate but short remission duration, the enzyme is currently employed
within the framework of combination chemotherapy schedules which achieve
treatment response in about 90% and long-term remissions in the majority of
patients. Recently initiated clinical trials have still confirmed the eminent
value of asparaginase in the combination chemotherapy of acute lymphatic
leukaemia and of some subtypes of non-Hodgkin lymphoma, and its important role as
an essential component of multimodal treatment protocols. Despite the unique
mechanism of action of this cytotoxic substance which shows relative selectivity
with regard to the metabolism of malignant cells, some patients experience toxic
effects during asparaginase therapy. Immunological reactions toward the foreign
protein include enzyme inactivation without any clinical manifestations as well
as anaphylactic shock. Severe functional disorders of organ systems result from
the impaired homeostasis of the amino acids asparagine and glutamine. The changes
affecting the proteins of the coagulation system have considerable clinical
impact as they may induce bleeding as well as thromboembolic events and may be
associated with life-threatening complications when the central nervous system is
involved. Risk factors predisposing to thromboembolic complications are
hereditary resistance against activated protein C and any other hereditary
thrombophilia. Other organ systems potentially affected by relevant functional
disorders are the central nervous system, the liver, and the pancreas, with
patients who have a history of pancreatic disorders carrying an especially high
risk of developing pancreatitis. Studies on the mechanisms of action and the
occurrence of resistance phenomena have shown that a treatment response may only
be expected if the malignant cells are unable to increase their asparagine
synthetase activity to an extent providing enough asparagine to the cell; one may
thus conclude that the enzyme-induced asparagine depletion of the serum
constitutes the decisive cytotoxic mechanism. Independent of the asparagine
depletion related cytotoxicity however, there are other mechanisms of clinical
relevance like induction of apoptosis. Besides this, further influences on signal
transduction cannot be excluded. Only few publications have dealt with the
question of minimum trough activities to be ensured before each subsequent
asparaginase dose in order to maintain uninterrupted asparagine depletion under
treatment, and answers to this problem are not definitive. Clinical studies using
enzymes from E. coli strains indicate that a trough activity of 100 U/l will
suffice for complete asparagine depletion of the fluid body compartments with the
preparations studied. These findings have been transferred to enzymes from other
E. coli strains as well as those isolated from Erwinia chrysanthemi and to the
PEG-conjugated E. coli asparaginases. It might be desirable to countercheck the
results for confirmation or correction. The dosage and administration schedule of
the various enzyme preparations required for complete asparagine depletion over a
period of time have been insufficiently defined. While pharmacokinetic studies
showed clinically relevant differences in biological activity and activity half
lives for enzymes from different biological sources, the findings of recently
published clinical trials indicate that the therapeutic efficacy is affected when
different asparaginase preparations are given by identical therapy schedules.
(ABSTRACT TRUNCATED)
PMID- 9768346
TI - Diet and breast cancer: an epidemiologist's perspective.
PMID- 9768347
TI - Fertility and pregnancy after adjuvant chemotherapy for breast cancer.
PMID- 9768348
TI - EBV genes and B cell proliferation.
PMID- 9768349
TI - Going for the GAP.
PMID- 9768350
TI - Single calponin homology domains are not actin-binding domains.
PMID- 9768351
TI - Hox genes: from master genes to micromanagers.
AB - We still have little idea how the differential expression of one 'master' gene
can control the morphology of complex structures, but recent studies suggest that
the Drosophila Hox gene Ultrabithorax micromanages segment development by
manipulating a large number of different targets at many developmental stages.
PMID- 9768352
TI - Bone remodelling: a signalling system for osteoclast regulation.
AB - Two physiological regulators of osteoclast maturation have recently been
identified: the secreted protein osteoprotegerin and the cell-surface ligand to
which it binds. These proteins are likely to play an important part in the
control of bone resorption, but are also likely to have important roles in other
tissues.
PMID- 9768353
TI - Transcriptional control: repression by local chromatin modification.
AB - It is becoming increasingly clear that chromatin modification plays a fundamental
part in transcriptional control. Recent studies provide new insights into how
transcriptional repressors, in addition to blocking activators, may recruit
repression complexes that include chromatin modification factors.
PMID- 9768354
TI - Size control: cell proliferation does not equal growth.
AB - Division subdivides mass without increasing it. So one should not expect that an
increase in cell division would make an organism bigger. Both classic and recent
experiments confirm this simple rationale: altering proliferation produces
normally sized body structures with either especially small or exceptionally
large cells.
PMID- 9768355
TI - Flowering time: from photoperiodism to florigen.
AB - An Arabidopsis blue-light receptor, Cry2, has been found to play a critical role
in the photoperiodic control of flowering time; and genes have been identified
that may control the production of a transmissible flower-inducing signal, which
may turn out to be the long-elusive putative flowering hormone 'florigen'.
PMID- 9768356
TI - Apoptosis: getting rid of the bodies.
AB - Cells that die by apoptosis need to be removed before lysis to preserve tissue
integrity and function. Recent studies have identified components of the uptake
machinery used by phagocytes, but much remains to be learnt, particularly about
the recognition mechanisms and their coupling to the uptake machinery.
PMID- 9768357
TI - Gene therapy: repairing haemoglobin disorders with ribozymes.
AB - A ribozyme-mediated approach has made it possible to replace the region in beta
globin mRNA containing the sickle-cell-anaemia mutation with a gamma-globin
encoding sequence. This is an interesting new way of correcting monogenic
disease, but there are major problems to overcome before it could be applied in
the clinic.
PMID- 9768358
TI - Multiple functions of the EGF receptor in Drosophila eye development.
AB - BACKGROUND: During animal development, cells need to make spatially and
temporally regulated fate decisions. These decisions are largely controlled by
intercellular signalling, often through receptor tyrosine kinases. One of these,
the epidermal growth factor receptor (EGFR), regulates multiple cell fate
decisions. Its importance in the recruitment of photoreceptors in the developing
fly eye, a useful model for neural development, has already been reported. Other
EGFR functions in the eye have not been characterised. RESULTS: We have examined
the consequences of removing or activating the EGFR at different stages of eye
development. The earliest stages of assembly occurred normally within EGFR-
clones--the morphogenetic furrow was unimpeded and the R8 photoreceptor was
specified. All subsequent photoreceptor recruitment was blocked. EGFR- clones had
a characteristic shape indicating that they had undergone substantial cell death
posterior to the furrow, where the differentiation program is normally activated;
consistent with this, excess apoptosis was detected. We found that the receptor
also regulates cell proliferation in the disc, has an early function at the disc
margin (where the morphogenetic furrow initiates) and contributes to the
regulation of spacing of the R8 precursors. Finally, we found that activation of
the receptor is sufficient to trigger non-R8 photoreceptor development, even in
cells in front of the furrow or in the absence of the proneural gene atonal.
CONCLUSION: At least five distinct functions of EGFR signalling need to be
integrated during fly eye development. These include roles in cell proliferation,
survival and differentiation.
PMID- 9768359
TI - Nuclear export of the stress-activated protein kinase p38 mediated by its
substrate MAPKAP kinase-2.
AB - BACKGROUND: Mitogen-activated protein (MAP) kinases (or extracellular signal
regulated kinases; Erks) and stress-activated protein (SAP) kinases mediate
cellular responses to a wide variety of signals. In the Erk MAP kinase pathway,
activation of MAP kinases takes place in the cytoplasm and the activated enzyme
moves to the nucleus. This translocation to the nucleus is essential to MAP
kinase signalling because it enables the kinase to phosphorylate transcription
factors. Whether components of the pathway mediated by the SAP kinase p38 change
their cellular location on activation is not clear; we have therefore studied the
cellular localisation of components of this pathway before and after stimulation.
RESULTS: The p38 SAP kinase substrate MAP-kinase-activated protein kinase-2
(MAPKAP kinase-2) contains a putative nuclear localisation signal which we show
is functional and required for activation by a variety of stimuli. Following
phosphorylation of MAPKAP kinase-2, nuclear p38 was exported to the cytoplasm in
a complex with MAPKAP kinase-2. Export of MAPKAP kinase-2 required
phosphorylation by p38 but did not appear to require the kinase activity of
MAPKAP kinase-2. The p38 activators MKK3 and MKK6 were present in both the
nucleus and the cytoplasm, consistent with a role in activating p38 in the
nucleus. CONCLUSIONS: In the p38 SAP kinase pathway, MAPKAP kinase-2 serves both
as an effector of p38 by phosphorylating substrates and as a determinant of
cellular localisation of p38. Nuclear export of p38 and MAPKAP kinase-2 may
permit them to phosphorylate substrates in the cytoplasm.
PMID- 9768361
TI - Regulation of protein kinase C zeta by PI 3-kinase and PDK-1.
AB - BACKGROUND: Protein kinase C zeta (PKC zeta) is a member of the PKC family of
enzymes and is involved in a wide range of physiological processes including
mitogenesis, protein synthesis, cell survival and transcriptional regulation. PKC
zeta has received considerable attention recently as a target of phosphoinositide
3-kinase (PI 3-kinase), although the mechanism of PKC zeta activation is, as yet,
unknown. Recent reports have also shown that the phosphoinositide-dependent
protein kinase-1 (PDK-1), which binds with high affinity to the PI 3-kinase lipid
product phosphatidylinositol-3,4,5-trisphosphate (Ptdins-3,4,5-P3),
phosphorylates and potently activates two other PI 3-kinase targets, the protein
kinases Akt/PKB and p70S6K. We therefore investigated whether PDK-1 is the kinase
that activates PKC zeta. RESULTS: In vivo, PI 3-kinase is both necessary and
sufficient to activate PKC zeta. PDK-1 phosphorylates and activates PKC zeta in
vivo, and we have shown that this is due to phosphorylation of threonine 410 in
the PKC zeta activation loop. In vitro, PDK-1 phosphorylates and activates PKC
zeta in a Ptdins-3,4,5-P3-enhanced manner. PKC zeta and PDK-1 are associated in
vivo, and membrane targeting of PKC zeta renders it constitutively active in
cells. CONCLUSIONS: Our results have identified PDK-1 as the kinase that
phosphorylates and activates PKC zeta in the PI 3-kinase signaling pathway. This
phosphorylation and activation of PKC zeta by PDK-1 is enhanced in the presence
of Ptdins-3,4-5-P3. Consistent with the notion that PKCs are enzymes that are
regulated at the plasma membrane, a membrane-targeted PKC zeta is constitutively
active in the absence of agonist stimulation. The association between PKC zeta
and PDK-1 reveals extensive cross-talk between enzymes in the PI 3-kinase
signaling pathway.
PMID- 9768360
TI - Sonic hedgehog signaling is essential for hair development.
AB - BACKGROUND: The skin is responsible for forming a variety of epidermal structures
that differ amongst vertebrates. In each case the specific structure (for example
scale, feather or hair) arises from an epidermal placode as a result of
epithelial-mesenchymal interactions with the underlying dermal mesenchyme.
Expression of members of the Wnt, Hedgehog and bone morphogenetic protein
families (Wnt10b, Sonic hedgehog (Shh) and Bmp2/Bmp4, respectively) in the
epidermis correlates with the initiation of hair follicle formation. Further,
their expression continues into either the epidermally derived hair matrix which
forms the hair itself, or the dermal papilla which is responsible for induction
of the hair matrix. To address the role of Shh in the hair follicle, we have
examined Shh null mutant mice. RESULTS: We found that follicle development in the
Shh mutant embryo arrested after the initial epidermal-dermal interactions that
lead to the formation of a dermal papilla anlage and ingrowth of the epidermis.
Wnt10b, Bmp2 and Bmp4 continued to be expressed at this time, however. When
grafted to nude mice (which lack T cells), Shh mutant skin gave rise to large
abnormal follicles containing a small dermal papilla. Although these follicles
showed high rates of proliferation and some differentiation of hair matrix cells
into hair-shaft-like material, no hair was formed. CONCLUSIONS: Shh signaling is
not required for initiating hair follicle development. Shh signaling is
essential, however, for controlling ingrowth and morphogenesis of the hair
follicle.
PMID- 9768362
TI - The Antirrhinum ERG gene encodes a protein related to bacterial small GTPases and
is required for embryonic viability.
AB - Small GTPases have diverse roles in animals and yeast, including signal
transduction, regulation of secretion, organisation of the cytoskeleton, and
control of cell division. Similar GTPases have also been found in bacteria, such
as the Escherichia coli GTPase ERA, which is involved in regulating metabolism
and cell division [1,2]. Many small GTPases have been cloned from plants but
their functional analysis has largely been limited to complementation of
mutations in corresponding yeast genes, and antisense experiments which have
implicated these proteins in processes such as root nodulation [3,4]. No
mutations in plant GTPases have been reported, and thus their true importance in
plant growth and development is unknown. Here we report the isolation of a gene
from Antirrhinum majus encoding a protein from an entirely novel class of
eukaryotic GTPases showing strongest similarity to the prokaryotic protein ERA.
We have named this gene ERG (for ERA-related GTPase). The ERG gene is expressed
in dividing or metabolically active cells. We generated a deletion allele of ERG
by site-selected transposon mutagenesis and have shown that seeds containing
embryos and endosperm homozygous for this deletion arrest soon after
fertilisation. We conclude that ERG has a crucial role in plant growth and
development, possibly by influencing mitochondrial division.
PMID- 9768363
TI - Sonic hedgehog regulates branching morphogenesis in the mammalian lung.
AB - The mammalian lung, like many other organs, develops by branching morphogenesis
of an epithelium [1]. Development initiates with evagination of two ventral buds
of foregut endoderm into the underlying splanchnic mesoderm. As the buds extend,
they send out lateral branches at precise, invariant positions, establishing the
primary airways and the lobes of each lung. Dichotomous branching leads to
further extension of the airways. Grafting studies have demonstrated the
importance of bronchial mesenchyme in inducing epithelial branching, but the
significance of epithelial signaling has largely been unstudied. The morphogen
Sonic hedgehog (Shh) is widely expressed in the foregut endoderm and is
specifically upregulated in the distal epithelium of the lung where branching is
occurring [2]. Ectopic expression of Shh disrupts branching and increases
proliferation, suggesting that local Shh signaling regulates lung development
[2]. We report here that Shh is essential for development of the respiratory
system. In Shh null mutants, we found that the trachea and esophagus do not
separate properly and the lungs form a rudimentary sac due to failure of
branching and growth after formation of the primary lung buds. Interestingly,
normal proximo-distal differentiation of the airway epithelium occurred,
indicating that Shh is not needed for differentiation events. In addition, the
transcription of several mesenchymally expressed downstream targets of Shh is
abolished. These results highlight the importance of epithelially derived Shh in
regulating branching morphogenesis of the lung.
PMID- 9768364
TI - Dynamics and ultrastructure of developmental cell fusions in the Caenorhabditis
elegans hypodermis.
AB - Cell fusions produce multinucleate syncytia that are crucial to the structure of
essential tissues in many organisms [1-5]. In humans the entire musculature, much
of the placenta, and key cells in bones and blood are derived from cell fusion.
Yet the developmental fusion of cell membranes has never been directly observed
and is poorly understood. Similarity between viral fusion proteins and recently
discovered cellular proteins implies that both cell-cell and virus-cell fusion
may occur by a similar mechanism [6-8]. Paradoxically, however, fusion of
enveloped viruses with cells involves an opening originating as a single pore [9
11], whereas electron microscopy studies of cell-cell fusion describe
simultaneous breakdown of large areas of membrane [12, 13]. Here, we have shown
that developmental cell fusion is indeed consistent with initiation by a virus
like, pore-forming mechanism. We examined live cell fusions in the epithelia of
Caenorhabditis elegans embryos by a new method that integrates multiphoton,
confocal, and electron microscopy. The fusion aperture always originated at a
single point restricted to the apical adherens junction and widened slowly as a
radial wavefront. The fusing membranes dispersed by vesiculation, rather than
simple unfolding of the conjoined double bilayer. Thus, in these cells fusion
appears to require two specialized sequential processes: formation of a unique
primary pore and expansion of the opening by radial internalization of the
interacting cell membranes.
PMID- 9768365
TI - Life extension and stress resistance in Caenorhabditis elegans modulated by the
tkr-1 gene.
AB - The nematode Caenorhabditis elegans is widely used to study aging, development,
behavior and other basic metazoan processes [1-3]. The only mutants directly
identified on the basis of their extended longevity in any metazoan have been
isolated in C. elegans [4,5]. All life-extension mutants (Age mutants) previously
identified in C. elegans result from hypo-morphic or nullo-morphic mutations. We
have identified a new class of gerontogene (a gene whose alteration causes life
extension) that increases life span when overexpressed. The first gene in this
class has been designated tyrosine kinase receptor-1 (tkr-1); it encodes a
putative receptor tyrosine kinase. Overexpression of tkr-1 in transgenics
increases longevity 40-100% (average 65%), confers increased resistance to heat
and ultraviolet (UV) irradiation in transgenic nematodes, and does not alter
development or fertility. Unlike previously identified gerontogenes, tkr-1
positively modulates stress resistance and longevity. These results further
support the positive relationship between increased stress resistance and
increased longevity seen in all previously studied longevity mutants. This
transgenic system is an effective means for identifying overexpression
gerontogenes.
PMID- 9768366
TI - A role of nicotinamide-induced increase in pancreatic beta-cell mass on blood
glucose control after discontinuation of the treatment in partially
pancreatectomized OLETF rats.
AB - Otsuka Long-Evans Tokushima Fatty (OLETF) rat, a model of NIDDM, is normoglycemic
at a young age. However, they become hyperglycemic, even at a young age as a
result of a 70% pancreatectomy, which is associated with insufficient
proliferation of beta-cells. Administration of nicotinamide ameliorates the
sustained hyperglycemia by increasing beta-cell proliferation. In order to
further understand its mode of action, we studied how long nicotinamide is
effective, in terms of ameliorating hyperglycemia, as evidenced by an increase in
beta-cell mass, after its administration, in partially pancreatectomized OLETF
rats. Male rats, 6 weeks of age, were allocated at random to two groups, 70%
pancreatectomy (Px) and sham-pancreatectomy (sham). The Px group was divided into
three subgroups, based on treatment with either nicotinamide (350 mg/kg),
phlorizin (400 mg/kg) or saline, which continued until 4 weeks after surgery, and
were sacrificed at 4, 6, or 8 weeks after surgery. A 70% Px resulted in sustained
hyperglycemia in the saline-treated Px rats, which was ameliorated by
administration of either phlorizin or nicotinamide, showing the non-fasting blood
glucose levels reached to or near the levels found in the sham rats. After
cessation of phlorizin injection, non-fasting blood glucose level increased
rapidly, reaching the level of the saline-treated Px rats at the end of the
experiment, whereas after cessation of nicotinamide injection, non-fasting blood
glucose increased gradually to a level which was significantly lower than that
observed in the saline-treated Px rats. An increased beta-cell mass, 62.7 +/-
7.8% of total beta-cell mass induced by nicotinamide at 4 weeks, decreased
gradually, reaching the level of pretreatment, 30.3 +/- 4.0% 4 weeks after
cessation of the treatment. The findings in this study suggest that ameliorated
hyperglycemia as a result of proliferated beta-cells during the administration of
nicotinamide may results in showing beta-cell exhaustion (a majority of beta-cell
degranulation) once stopping injection, as compared with phlorizin treated group
in this model rat.
PMID- 9768367
TI - Ultrastructural evaluation of B-cell recruitment in virgin and pregnant offspring
of diabetic mothers.
AB - Adult offspring of diabetic rat mothers display a disturbed glucose tolerance and
gestational diabetes. The amount of endocrine pancreas and of B-cells is largely
sufficient in these non-pregnant and pregnant youngsters. The present work aims a
morphometric evaluation of B-cell activity in adult youngsters from control,
mildly and severely diabetic mothers, in basal condition and in their adaptation
to pregnancy. B-cells are divided, on basis of the ultrastructural morphology of
their organelles, in dark non-activated B-cells and pale activated B-cells. These
data are related to the concepts of functional B-cell heterogeneity and dose
dependent recruitment of pancreatic B-cells on stimulation. The recruitment of B
cells in each of the groups is evaluated from the proportion pale/dark B-cells.
In control animals this is about 50/50, in both experimental groups there is a
marked predominance of pale B-cells. During normal pregnancy, a shift occurs
towards a majority of pale B-cells. In the offspring of diabetic mothers, the
ratio does not further change during gestation. It can be concluded that the
disturbance in B-cell stimulation and the development of gestational diabetes in
offspring of diabetic mothers is associated with a maximal recruitment of the B
cells already in basal non-pregnant condition.
PMID- 9768368
TI - Comparison of NovoPen 3 and syringes/vials in the acceptance of insulin therapy
in NIDDM patients with secondary failure to oral hypoglycaemic agents.
AB - This open, randomised, cross-over study compared the acceptance and safety of
NovoPen 3 with that of conventional syringes and vials when initiating insulin
treatment in 96 NIDDM patients with secondary failure to oral hypoglycaemic
agents. These patients had not previously been treated with insulin. All patients
used each insulin administration system for 12 weeks. Group A started therapy
using NovoPen 3 and crossed over to syringe/vial administration; Group B started
with syringe/vial administration followed by NovoPen 3. In total, 78 patients
completed the study. Most patients in Group A initially found the insulin
injections very easy or easy and many of those who found injections easy at first
found them very easy by the end of week 12. During the first period, patients in
Group B found insulin administration more difficult than those in Group A.
Injection pain was significantly lower with NovoPen 3 than with syringes and
vials (P = 0.0018). Patients in Group B reported a significantly lower level of
injection pain after the switch to using NovoPen 3 (P = 0.0003). Acceptance of
insulin injections was significantly higher by patients using NovoPen 3 than by
those using syringes and vials (P = 0.0059). Setting and drawing up the dose of
insulin was also easier for patients using NovoPen 3 (P = 0.0490). At the end of
the study, most patients (89.5% (68/76 replies)) said that they preferred NovoPen
3 to syringes and vials. Glycaemic control improved compared with baseline after
starting insulin therapy, with no differences between Groups A and B, or between
the two injection systems. The number of reported hypoglycaemic episodes was very
low and was not significantly different between Groups A and B, or between the
two administration systems. No treatment-related adverse events were reported. We
conclude that use of NovoPen 3 provides better acceptance of insulin injection
than use of conventional syringes and vials during initiation of insulin therapy
in NIDDM patients with secondary failure to treatment with oral hypoglycaemic
agents.
PMID- 9768369
TI - Antibodies to glutamic acid decarboxylase (GAD) in non-obese Japanese diabetics
without insulin therapy: a comparison of two commercial RIA kits based on
recombinant and pig brain GAD.
AB - To compare the clinical usefulness of commercial radioimmunoassay (RIA) kits
based on recombinant and pig brain GAD, we measured glutamic acid decarboxylase
autoantibody (GADAb) titers in 125 non-obese (body mass index < 24) Japanese
diabetics without insulin therapy using two commercial RIA kits based on
recombinant human (rh) GAD65 (GADAb Cosmic) and purified pig brain native GAD
(RIP Anti-GAD Hoechst). The frequencies of GADAb positivity using these two RIA
kits (normal ranges; < 1.3 and < 4.0 U/ml, respectively) were about 4.8 (6/125)
and 3.2% (4/125), respectively. The six patients found to be positive with RIA
using GADAb Cosmic demonstrated significantly higher prevalence of NIDDM in their
parents (P = 0.04), lower beta-cell function estimated by intravenous glucagon
loading tests (P = 0.03) and higher prevalence of progression to insulin therapy
(P = 0.0001). Five of these six patients slowly progressed to insulin-requiring
status within 34 +/- 11 months of follow-up evaluation, and one of these five
patients progressed to a completely insulin-dependent status within 30 months
from the onset of diabetes. Of these six patients, two demonstrated chronic
pancreatitis, three had chronic thyroiditis, and five showed HLA DR4.
Interestingly, two of the six patients demonstrated very low GADAb titers (2.3
and 2.9 U/ml), while RIP Anti-GAD Hoechst showed no positivity with the same
sera. Based on the binding study after pre-incubation of unlabeled GADs, these
low titrated GADAb were elucidated to be true specific reactions to rh GAD65
alone. Moreover, one of the two patients with chronic thyroiditis and HLA DR4
slowly progressed to insulin-requiring status over a period of 45 months. These
findings suggest that the measurement of GADAb using a commercial assay kit with
rh GAD65 may be more useful to detect non-insulin-dependent type I diabetics
among non-obese patients than using a commercial kit with purified pig brain
native GAD, especially among those with low GADAb titers.
PMID- 9768370
TI - Pioglitazone enhances splanchnic glucose uptake as well as peripheral glucose
uptake in non-insulin-dependent diabetes mellitus. AD-4833 Clamp-OGL Study Group.
AB - To evaluate the effect of pioglitazone on insulin resistance in non-insulin
dependent diabetes mellitus (NIDDM) patients, a double-blind placebo-controlled
trial was carried out with 30 NIDDM patients. Twenty-one subjects, three on diet
alone and 18 on sulfonylurea (SU), orally received 30 mg pioglitazone once daily
for 12 weeks. Nine subjects, one on diet alone and eight on SU, received a
matching placebo once daily for 12 weeks. Euglycemic (5.2 mmol/l)
hyperinsulinemic (1200 pmol/l) clamp combined with an oral glucose load (OGL) was
performed before and after 3-month treatment with pioglitazone or placebo to
determine insulin-stimulated glucose disposal and splanchnic glucose uptake
(SGU). No significant differences existed in the patients' characteristics,
including age and body mass index, between the two study groups. The pioglitazone
treatment increased the mean glucose infusion rate (GIR) prior to OGL from 8.2 +/
2.2 to 9.2 +/- 2.0 mg/kg.min (mean +/- SD, P = 0.003) and increased the SGU rate
from 28.5 +/- 19.4 to 59.4 +/- 27.1% (P = 0.010). The placebo treatment produced
no significant changes in either GIR or SGU after treatment. A significant
difference (P = 0.042) was observed in change of SGU between the pioglitazone and
placebo treatment groups. In conclusion, the results indicate that pioglitazone
is effective for ameliorating insulin resistance in NIDDM by enhancing SGU as
well as peripheral glucose uptake.
PMID- 9768371
TI - An atherogenic midband lipoprotein: a risk factor for coronary artery disease in
diabetes mellitus with hyperlipidemia.
AB - On polyacrylamide gel (PAG) disc electrophoresis of serum lipoproteins, the
band(s) which migrates between pre beta- and beta-lipoproteins was more
frequently observed in hyperlipidemics with diabetes mellitus (73%), than in
those without diabetes mellitus (37%) (P < 0.01). Those bands were seen at three
positions between pre beta- and beta-lipoproteins. A higher incidence of coronary
artery disease (CAD) was observed in patients with midband as a shoulder of beta
lipoproteins (44%), than in those without midband (11%) (P < 0.05) after the
matching of other risk factors. These results suggest that midband as a shoulder
of beta-lipoproteins may be a risk factor for CAD in diabetes mellitus with
hyperlipidemia.
PMID- 9768372
TI - Effect of acarbose on postprandial lipid metabolism in type 2 diabetes mellitus.
AB - The effect of acarbose, an alpha-glucosidase inhibitor, on postprandial glucose
and lipid metabolism was investigated in patients with type 2 diabetes mellitus.
Twenty patients (10 men and 10 women) with type 2 diabetes mellitus were studied.
A test meal was taken with or without 100 mg of acarbose. The levels of plasma
glucose, and serum immunoreactive insulin, lipids, apolipoproteins, and remnant
like particle cholesterol were investigated. Acarbose inhibited the postprandial
increase of both plasma glucose and serum immunoreactive insulin. Acarbose also
significantly suppressed the increase of serum triglycerides at 60, 90, and 120
min (P < 0.05 to P < 0.01), and the increase of serum remnant-like particle
cholesterol at 60 and 120 min (P < 0.05). Acarbose inhibited the postprandial
decline of apolipoprotein C-II, and decreased the postprandial serum
apolipoprotein C-III level. These results suggest that acarbose may improve
postprandial hyperlipidemia as well as postprandial hyperglycemia in patients
with type 2 diabetes mellitus.
PMID- 9768373
TI - The effect of low intensity bicycle exercise on the insulin-induced glucose
uptake in obese patients with type 2 diabetes.
AB - OBJECTIVE: The present study was undertaken to reveal the effect of low intensity
bicycle exercise on the insulin-induced glucose uptake in obese patients.
SUBJECTS AND METHODS: Seven obese men with Type 2 diabetes (OBDM) and seven
healthy young men (HY) participated in this study. The glucose infusion rate
(GIR) was determined by glucose clamp procedure at an insulin infusion rate of 40
mU m-2 min-1 (plasma insulin concentrations: 700-800 pmol l-1). Confirming
stabilized GIR, a 30-min bicycle exercise was performed during the glucose clamp
which was continued for 120 min after exercise. RESULTS: Average GIR in OBDM for
last 30 min prior to exercise were significantly lower than HY (28.3 +/- 1.7,
47.4 +/- 1.8 mumol kg-1 min-1 respectively, P < 0.05). GIR abruptly increased
during exercise and gradually decreased after exercise to the nadir almost at the
time from 30 to 60 min in recovery period in both groups. GIR in OBDM, however,
gradually increased significantly over pre-exercise levels (P < 0.05), following
exercise and reached the same levels compared to HY after 80 min of recovery
period. CONCLUSION: These results indicated that in obese Type 2 diabetes, 30 min
of low intensity bicycle exercise significantly enhances the lower level of
insulin-induced glucose uptake shortly after exercise and might be useful for the
treatment of post-prandial hyperglycemia.
PMID- 9768374
TI - Peripheral neuropathy, hypertension, foot ulcers and amputations among Saudi
Arabian patients with type 2 diabetes.
AB - Three hundred and seventy-five Saudi Arabian patients with type 2 diabetes were
consecutively examined for peripheral neuropathy, foot ulcers, amputations and
hypertension. All the 46-69-year-old patients (n = 212) were compared to a
corresponding Swedish group seen by the same physician using identical approach
and definitions. Vibration sensitivity was examined using a tuning fork. Pin
prick sensitivity using a needle on the plantar and dorsal aspects of the foot.
Distal neuropathy was defined as complete absence of vibration and/or pin prick
sensitivity in an extremity. With a diabetes duration of 10 or more years the
prevalence of neuropathy among the 375 Saudi Arabians was 38% (95% confidence
intervals 30-45); hypertension 19% (13-25) current and past ulcers 4.7% (1.3-8);
amputations below ankle 3.4% (0.5-6). In the selected 46-69-year-old group
prevalence of hypertension (17%), ulcers (2.3%) and amputation (1%) was
significantly lower in the Saudi Arabian than in the Swedish patients. The
frequencies reported here are the first from the Arab Peninsula. The Saudi
Arabian patients with type 2 diabetes have the same prevalence of distal
neuropathy as other ethnic groups. A low prevalence of hypertension is consistent
with findings in expatriate and indigenous Arab groups with type 2 diabetes. The
low occurrence of ulcers and amputations may be explained by different styles of
footwear.
PMID- 9768375
TI - Effects of genetic predisposition on proinsulin responses in Asian Indians.
AB - This study was done in adult offspring of two diabetic (NIDDM) parents (ODP) to
look for changes in specific insulin (insulin) and proinsulin responses due to
strong familial background and also in different states of glucose intolerance.
Equal numbers (20 in each group) of ODP with normal glucose tolerance (NGT),
impaired glucose tolerance (IGT) and diabetes (DM) were chosen. Twenty, age and
BMI matched healthy controls, without family history of diabetes, were also
studied for comparison. Plasma specific insulin and proinsulin were measured by
radioimmunoassays in fasting and 120' plasma samples collected during the GTT.
Proinsulin to insulin ratio were calculated. Insulin resistance (IR-HOMA) was
calculated. In NGT, fasting proinsulin-insulin ratio was significantly higher
than the control value (P = 0.023). Insulin values at 120' was higher than
control values, though it did not reach statistical significance. Proinsulin at
120' was higher than controls (P = 0.016). In IGT, the fasting proinsulin to
insulin ratio, the 120' proinsulin and insulin values were higher than controls
(P = 0.048, 0.0013 and 0.0001, respectively). Fasting proinsulin-insulin ratio in
IGT was similar to the value in NGT. In diabetic subjects proinsulin
concentrations were significantly higher than controls at fasting (P = 0.0004),
and 120' (P = 0.0007). The fasting values were higher compared to NGT also (P =
0.037). Proinsulin-insulin ratios were higher than the values in controls (P =
0.0008), IGT (P = 0.047) and NGT (P = 0.05). Diabetic subjects had higher fasting
insulin values compared to the control values although between the groups no
statistical significance was found (P = 0.22 by Kruscall Wallis test). At 120'
both insulin and proinsulin values increased from NGT to IGT, but with
development of diabetes a reduction was seen in the responses. Insulin resistance
(IR-HOMA) increased steadily from NGT to diabetes. The difference between NGT and
controls in IR was not statistically significant. This study of Asian Indian
offspring of diabetic parents has shown that genetic predisposition to diabetes
resulted in increased proinsulin to insulin ratio at the fasting state. Absolute
hyperproinsulinaemia occurred only with development of diabetes.
PMID- 9768376
TI - Intervention mapping: a process for developing theory- and evidence-based health
education programs.
AB - The practice of health education involves three major program-planning
activities: needs assessment, program development, and evaluation. Over the past
20 years, significant enhancements have been made to the conceptual base and
practice of health education. Models that outline explicit procedures and
detailed conceptualization of community assessment and evaluation have been
developed. Other advancements include the application of theory to health
education and promotion program development and implementation. However, there
remains a need for more explicit specification of the processes by which one uses
theory and empirical findings to develop interventions. This article presents the
origins, purpose, and description of Intervention Mapping, a framework for health
education intervention development. Intervention Mapping is composed of five
steps: (1) creating a matrix of proximal program objectives, (2) selecting theory
based intervention methods and practical strategies, (3) designing and organizing
a program, (4) specifying adoption and implementation plans, and (5) generating
program evaluation plans.
PMID- 9768377
TI - Intervention mapping and the new health promotion.
PMID- 9768378
TI - Preventing the spread of genital warts: using fear appeals to promote self
protective behaviors.
AB - A fear appeal campaign to decrease the spread of genital warts was conducted and
evaluated. Theoretically guided by the Extended Parallel Process Model, this
field study illustrated why fear appeal campaigns often appear to fail in public
health arenas. Five hypotheses, which predicted when and under what conditions
fear appeal campaigns would fail or succeed, were tested and supported. The
results demonstrated that fear appeals can be powerful persuasive devices if they
induce strong perceptions of threat and fear (which motivate action) and if they
induce strong perceptions of efficacy with regard to a recommended response
(which channels the action in a health protective direction). Recommendations to
researchers and public health practitioners are offered.
PMID- 9768379
TI - Social support and readiness to make dietary changes.
AB - This article examines the relationship between reported social support and
readiness to increase fruit and vegetable consumption, based on the
Transtheoretical Stage of Change Model. Data were collected as part of the
baseline assessments for a work site intervention study promoting increased
consumption of fruits and vegetables. Among workers who did not live alone,
household support was significantly higher for those of Hispanic and African
American heritage than other groups, and was also higher among men, nonsmokers,
and those living with adults compared to those living only with children. In
multivariate analyses, coworker support was significantly associated with being
in preparation compared to precontemplation/contemplation. Household support was
not significantly related to readiness to change in multivariate analyses. The
effectiveness of work site nutrition education interventions is likely to be
enhanced by teaching participants to provide social support to coworkers and
family members.
PMID- 9768380
TI - Social support and coping behaviors of low-income families experiencing food
insufficiency in North Carolina.
AB - The Food Research and Action Center estimates that approximately 12% of all
families with children younger than 12 years old experience food insufficiency in
the United States. The authors conducted 16 focus groups with 141 participants,
who were either at risk or experienced food insufficiency, to learn about coping
strategies. Individual and network-level coping mechanisms were used to manage
insufficient food supply. Social networks included family, friends, and
neighbors. The assistance provided included food aid, information, and emotional
support. Not all networks were relied on or accessed by everyone. Most
participants reported that they relied on family members first, followed by
friends, and then neighbors. Parents found reliance on anyone as stressful and
often threatening. In conclusion, as the social welfare system becomes
constrained, more and more households may experience food insufficiency.
Responsive policies are therefore needed to assist low-income families.
PMID- 9768381
TI - Practical assessment of adult literacy in health care.
AB - Low literacy is a pervasive and underrecognized problem in health care
Approximately 21% of American adults are functionally illiterate, and another 27%
have marginal literacy skills. Such patients may have difficulty reading and
understanding discharge instructions, medication labels, patient education
materials, consent forms, or health surveys. Properly assessing the literacy
level of individual patients or groups may avoid problems in clinical care and
research. This article reviews the use of literacy assessments, discusses their
application in a variety of health care settings, and cites issues providers need
to consider before testing. The authors describe informal and formal methods of
screening for reading and comprehension in English and Spanish including the
Rapid Estimate of Adult Literacy in Medicine, the Wide Range Achievement Test-3,
the Cloze procedure, the Test of Functional Health Literacy in Adults, and
others. Practical implications and recommendations for specific use are made.
PMID- 9768382
TI - Longitudinal study of relapse from AIDS-preventive behavior among homosexual men.
AB - There is no viable alternative to the control of AIDS besides prevention; factors
contributing to relapse from behaviors presumed to reduce risk of that disease
were investigated. The authors studied 524 homosexual men who had refrained from
or used condoms during receptive or insertive anal sex (RAS and IAS,
respectively) for at least 12 months, contacting them at 6-month intervals
thereafter to ascertain current practices. They determined, via interviews,
personal traits, appraised stress of maintaining safer sex, mental health, life
events, and efforts to cope with potential infection. Negative life events,
personal control beliefs, problem-solving abilities, and coping via problem
focused (e.g., seeking a monogamous union) rather than emotion-focused (e.g.,
"when I need a cure, they will have one") behaviors were associated with RAS, but
less so with IAS safer sex behaviors. These findings provide a basis for
individual and community-level interventions to change behavior and reduce AIDS
risk.
PMID- 9768383
TI - Physical activity and minority women: a qualitative study.
AB - Few physical activity research studies have been conducted with minority women.
The purpose of this study was to explore patterns of physical activity among
minority women. Focus groups were conducted with volunteers older than age 40.
Each group was led by a trained moderator familiar with the ethnic community
targeted. The sessions were audiotaped and professionally transcribed. Constructs
were researched and codes were developed. Data were analyzed using NUD*IST
qualitative analysis program. While participants did not identify themselves as
"exercisers," they indicated they got enough physical activity from caregiving,
housekeeping, and workday activities. The most common environmental barriers to
becoming more physically active included safety, availability, and cost. Personal
barriers included lack of time, health concerns, and lack of motivation. Results
indicate the importance of terminology and assessment when conducting physical
activity research in these populations. Also, results suggest many barriers are
changeable with policies and interventions.
PMID- 9768384
TI - Improving breast cancer control among Latinas: evaluation of a theory-based
educational program.
AB - The study evaluated a theory-based breast cancer control program specially
developed for less acculturated Latinas. The authors used a quasi-experimental
design with random assignment of Latinas into experimental (n = 51) or control (n
= 37) groups that completed one pretest and two posttest surveys. The
experimental group received the educational program, which was based on Bandura's
self-efficacy theory and Freire's empowerment pedagogy. Outcome measures included
knowledge, perceived self-efficacy, attitudes, breast self-examination (BSE)
skills, and mammogram use. At posttest 1, controlling for pretest scores, the
experimental group was significantly more likely than the control group to have
more medically recognized knowledge (sum of square [SS] = 17.0, F = 6.58, p <
.01), have less medically recognized knowledge (SS = 128.8, F = 39.24, p < .001),
greater sense of perceived self-efficacy (SS = 316.5, F = 9.63, p < .01), and
greater adeptness in the conduct of BSE (SS = 234.8, F = 153.33, p < .001).
Cancer control programs designed for less acculturated women should use informal
and interactive educational methods that incorporate skill-enhancing and
empowering techniques.
PMID- 9768385
TI - Fluorescein-stained capsulorhexis.
PMID- 9768386
TI - About encircling haptics.
PMID- 9768387
TI - Complications with the passport placement system.
PMID- 9768388
TI - Consultation section. Refractive surgical problem.
PMID- 9768389
TI - Blunt, bent needle for continuous curvilinear capsulorhexis.
AB - We describe an anterior continuous curvilinear capsulorhexis (CCC) technique that
uses a dull needle. The needle's blunt tip prevents inadvertent tearing of the
anterior capsule, and its rough surface allows the surgeon to transmit a power
vector of different amplitude and direction to the edge of the capsulorhexis to
continue the tear as desired. For biomechanical reasons, we prefer an arcade
shaped CCC because this configuration provides a greater circumference than a
circular CCC. The blunt needle allows one to perform a single-step capsulorhexis
in a safe and controlled manner and reduces surgical time. Even in cases of white
and liquified cortex, the dull needle has proved a useful, safe tool.
PMID- 9768390
TI - Axial, instantaneous, and refractive formulas in computerized videokeratography
of normal corneas.
AB - PURPOSE: To compare the values for corneal power determined by the axial,
instantaneous and refractive formulas when imaging normal human corneas using
computerized videokeratography. SETTING: Cullen Eye Institute, Baylor College of
Medicine, Houston, Texas, USA. METHODS: This prospective clinical trial involved
60 corneas of 30 normal volunteers. Computerized videokeratography was performed
to determine corneal power at the center and the 1, 3, 5, and 7 mm zones using
the 3 formulas. RESULTS: Mean central corneal power was 42.86 diopters (D) with
each of the formulas. The mean corneal powers for the axial, instantaneous, and
refractive formulas were 43.09, 43.21, and 42.98 D at the 1 mm zone; 43.10,
42.92, and 43.46 D at the 3 mm zone; 42.75, 41.63, and 44.02 at the 5 mm zone;
42.21, 40.30, and 44.79 D at the 7 mm zone, respectively. The differences among
powers for the 3 formulas at the 3, 5, and 7 mm zones were statistically
significant (P < .01). CONCLUSION: In normal corneas, clinically significant
differences exist in the corneal power values calculated by the axial,
instantaneous, and refractive formulas.
PMID- 9768391
TI - Noncontact thermokeratoplasty to correct hyperopia induced by laser in situ
keratomileusis.
AB - PURPOSE: To evaluate the efficacy and safety of noncontact holmium:YAG (Ho:YAG)
laser thermokeratoplasty (LTK) for treating hyperopia induced by laser in situ
keratomileusis (LASIK). SETTING: Department of Ophthalmology, University of
Alicante, Instituto Oftalmologico de Alicante, Alicante, Spain, and the
University of Al-Azhar, Cairo, Egypt. METHODS: Noncontact LTK was applied to 13
eyes (11 patients) with significant hyperopia after LASIK using a Ho:YAG laser
(model gLase 210, Sunrise Technologies). Mean spherical equivalent before LTK was
+4.60 diopters (D) +/- 1.40 (SD) (range +2.50 to +7.25 D). The results were
evaluated 18 months after the LTK surgery. RESULTS: A significant myopic shift
developed in all eyes that gradually receded to emmetropia 6 to 8 weeks after
LTK. After 12 months, refraction was relatively stable. At 18 months, there was a
statistically significant difference between the mean uncorrected visual acuity
(UCVA) before LTK (0.19 +/- 0.09) and mean postoperative UCVA (0.61 +/- 0.22) (P
< .005). At the end of the study, there was a mean increase of 4.10 +/- 1.12 D in
central keratometric power. Total regression did not occur in any eye.
CONCLUSION: Noncontact Ho:YAG LTK was safe and effective in correcting LASIK
induced hyperopia. The cutting of Bowman's layer and a thinner corneal center may
contribute to the stability of LTK in such cases.
PMID- 9768392
TI - Diode laser thermokeratoplasty: application strategy and dosimetry.
AB - PURPOSE: To investigate suitable application parameters for efficient hyperopic
correction by laser thermokeratoplasty (LTK) using mid-infrared laser diodes.
SETTING: Medical Laser Center Lubeck, Lubeck, Germany. METHOD: A tunable
continuous-wave laser diode in the spectral range between 1.845 and 1.871 microns
was used. Transmitted by waveguides, the laser energy was used to induce
coagulations on freshly enucleated porcine eyes to increase corneal curvature.
The coagulations were equidistantly applied by a fiber-cornea contact and a
noncontact focusing device that were adjusted on a ring concentric to the corneal
apex. Different laser parameters and application geometries were evaluated.
Refractive changes were measured by computer-assisted corneal topography before
and after treatment. Polarization light microscopy and temperature calculations
were used to analyze the coagulations. RESULTS: Because of the tunability of the
laser diode, the influence of the corneal absorption coefficient (between 0.9 and
1.6 mm-1) on the refractive change could be measured. A laser power between 125
and 200 mW was adequate to achieve refractive changes up to 10.0 diopters. In the
preferable focusing device, the refractive change increased almost
logarithmically with the irradiation time up to 15 seconds. The number of
coagulations on a fixed application ring showed no significant influence on
refractive change; however, it showed an almost linear decrease with increasing
ring diameter from 5.0 to 10.0 mm. Histological analysis revealed 3 stages of
thermal damage. CONCLUSION: Diode LTK provided defined and uniform coagulations
when using a well-adapted focusing device, resulting in sufficient refractive
change. The results indicate that diode LTK is superior to pulsed holmium LTK.
PMID- 9768393
TI - Laser in situ keratomileusis after photorefractive keratectomy for myopic
regression.
AB - PURPOSE: To assess the efficacy and safety of laser in situ keratomileusis
(LASIK) for regression after excimer laser photorefractive keratectomy (PRK).
SETTING: Eye Research Center, Istanbul University, Istanbul, Turkey. METHODS:
Laser in situ keratomileusis to treat residual myopia ranging from 1.50 to 12.50
diopters (D) (mean 5.96 D +/- 3.06 [SD]) was performed in 45 eyes of 25 patients.
Cylindrical corrections were done in 7 eyes (15.6%) and spherical ablations, in
38 (84.4%). The mean interval between primary PRK and LASIK retreatment was 18.50
+/- 8.12 months. The procedure was performed under a hinged corneal flap using
the Chiron Automated Corneal Shaper and Chiron Keracor 116 excimer laser.
RESULTS: Six months after LASIK retreatment, mean spherical equivalent refraction
was -0.67 +/- 0.77 D. Thirty-six eyes (80%) were within +/- 1.00 D of emmetropia.
Uncorrected visual acuity was 20/40 or more in 31 eyes (68.9%); 2 eyes (4%) lost
2 lines of best spectacle-corrected visual acuity. There was no statistically
significant difference in corneal haze before and after LASIK. CONCLUSION: Laser
in situ keratomileusis was safe and effective for treating residual myopia after
excimer laser PRK.
PMID- 9768394
TI - Corneal topography in Ehlers-Danlos syndrome.
AB - PURPOSE: To assess the use of corneal topography in conjunction with slitlamp
biomicroscopy and retinoscopy to diagnose keratoconus in a large group of
patients with Ehlers-Danlos syndrome (EDS). SETTING: Kresge Eye Institute, Wayne
State University, Detroit, Michigan, USA. METHODS: Thirty-six patients (72 eyes)
with genetically typed EDS had slitlamp biomicroscopy, retinoscopy, and
videokeratography with the EyeSys instrument. The presence or absence of slitlamp
keratoconus findings was correlated to a presumptive diagnosis based on corneal
topography using derived topographic indexes associated with keratoconus. These
topographic indexes included central corneal power, (CCP), difference in CCP,
inferosuperior asymmetry (I-S) value, and asphericity (Q). Axial and profile
difference maps were generated and analyzed for findings suggestive of
keratoconus. RESULTS: In 72 eyes, no keratoconus was found using slitlamp
biomicroscopy. No eye had an I-S value greater than 1.60 diopters (D), 2 eyes had
a CCP greater than 46.50 D, and 2 eyes had a Q value less than -1.00. Eight of 36
pairs of eyes had an intereye CCP greater than 0.92 D. In both eyes of the
patient with Q values less than -1.00 the profile difference maps were mildly
abnormal. CONCLUSIONS: Slitlamp biomicroscopy of the cornea was unremarkable in
all patients. Only 1 patient had Q values and profile difference maps that were
mildly suggestive of keratoconus. Even after adding topography to the
examination, it appears that keratoconus in a known population of patients with
EDS remains rare.
PMID- 9768395
TI - Anterior capsule contraction with foldable silicone intraocular lenses.
AB - PURPOSE: To examine the causes signs, and symptoms of anterior capsule
contraction syndrome and the response to neodymium YAG (Nd:YAG) anterior
capsulotomy. SETTING: Madigan Army Medical Center, Tacoma, Washington, USA.
METHODS: This retrospective review comprised 70 cases of phacoemulsification with
foldable plate-haptic silicone intraocular lens (IOL) implantation. Patients who
developed anterior capsule contraction postoperatively, defined as the anterior
capsule being visible through an undilated pupil, had a radial anterior
capsulotomy with an Nd:YAG laser. Variables analyzed were visual acuity,
subjective complaints, associated inflammation, and IOL decentration. RESULTS:
Ten eyes of 9 patients (14%) developed anterior capsule contraction and had
Nd:YAG laser radial anterior capsulotomy. Three of 9 patients reported decreased
visual acuity and glare. Two other patients had chronic anterior chamber
inflammation unresponsive to steroids after surgery that resolved after Nd:YAG
anterior capsulotomy. Intraocular lens decentration was observed in 3 patients
before the Nd:YAG capsulotomy. Posterior lens dislocation occurred in 1 patient
after capsulotomy and required surgical lens exchange. CONCLUSION: One-piece
foldable silicone IOLs may not provide enough peripheral capsule expansion.
PMID- 9768396
TI - Cartridge cracks during foldable intraocular lens insertion.
AB - PURPOSE: To assess the incidence of cartridge cracks during foldable intraocular
lens (IOL) insertion and to determine factors that play a role in the development
of these cracks. SETTING: Leesburg Regional Ambulatory Surgical Care Center,
Leesburg, Florida, USA. METHODS: Small incision cataract surgery was performed in
350 consecutive cases. A foldable silicone IOL (Allergan Medical Optics SI-40)
was inserted in all cases using the Unfolder cartridge and 3 viscoelastic agents:
sodium hyaluronate (Healon, Vitrax) and sodium chondroitin sulfate-sodium
hyaluronate (Viscoat). RESULTS: Cartridge cracks occurred in 52 eyes (14.86%).
Almost all cracks (98.1%) occurred in cases in which Healon was used to load the
IOL. In each case of a cracked cartridge, there was evidence of the plunger
overriding the optic edge. CONCLUSIONS: We recommend the use of chondroitin-based
viscoelastic agents to load the SI-40 foldable IOL to minimize the risk of
cartridge cracks. Modifications in the design of the IOL inserter may eliminate
the problem of cartridge cracks.
PMID- 9768397
TI - Transscleral fixation of acrylic intraocular lenses in the absence of capsular
support through 3.5 mm self-sealing incisions.
AB - PURPOSE: To evaluate the safety and efficacy of transscleral ciliary sulcus
fixation of acrylic intraocular lenses (IOLs) through small incisions in the
management of secondary IOL implantation. SETTING: Department of Ophthalmology,
Osaka Rosai Hospital, Osaka, Japan. METHODS: This retrospective study consisted
of 28 patients (30 eyes) who had transscleral fixation of acrylic IOLs through
3.5 mm incisions. All patients were followed for a minimum of 6 months in several
different clinical settings. Data on visual acuity, keratometry, and central
corneal endothelial cell count were evaluated preoperatively and postoperatively.
The refractive error achieved and incidence of postoperative complications were
determined. RESULTS: Uncorrected visual acuity (UCVA) improved in all eyes. Of
the 18 eyes without pre-existing pathology, 11 (61.1%) had a UCVA of 20/40 or
better from 1 week postoperatively. Best corrected visual acuity was unchanged in
24 eyes (80.0%) and improved by 2 Snellen lines or more in 5 eyes (16.7%) at the
final examination. Self-sealing wound adaptation was achieved in 25 eyes (83.3%).
The mean scalar shift in keratometric cylinder was 1.25 diopters (D) at 1 day
postoperatively, 1.17 D at 1 week, and 1.06 D at 3 months. The rate of central
corneal endothelial loss 6 months postoperatively averaged 7.84%. No
intraoperative complications that were directly associated with acrylic IOL
implantation occurred. Postoperative complications that included transient ocular
hypertension, slight vitreous hemorrhage, and IOL malposition were found in a
small population but resolved spontaneously without further surgical
intervention. CONCLUSIONS: The good visual outcomes and low incidence of
complications achieved in the present study indicate that acrylic IOLs positioned
through small incisions might be considered for ciliary sulcus fixation. However,
evaluation of this technique in a large population over the long term is
required.
PMID- 9768398
TI - New classification of capsular block syndrome.
AB - PURPOSE: To propose a new classification of capsular block syndrome (CBS) to
improve understanding of the etiology and provide effective treatment. SETTING:
Shohzankai Medical Foundation, Miyake Eye Hospital, Nagoya, and Japanese Red
Cross Society, Wakayama Medical Center, Wakayama, Japan. METHODS: Three groups of
eyes with CBS were reviewed: eyes originally reported and diagnosed as having
CBS; eyes experiencing CBS after hydrodissection and luxation of the lens
nucleus; and eyes with CBS accompanying liquefied aftercataract or capsulorhexis
related lacteocrumenasia. RESULTS: In all 3 groups, the CBS occurred in eyes with
a continuous curvilinear capsulorhexis (CCC). It was characterized by
accumulation of a liquefied substance within a closed chamber inside the capsular
bag, formed because the lens nucleus or the posterior chamber intraocular lens
(IOL) optic occluded the anterior capsular opening created by the CCC. Depending
on the time of onset, CBS can be classified as intraoperative (CBS seen at the
time of lens luxation following hydrodissection), early postoperative (original
CBS), and late postoperative (CBS with liquefied aftercataract or
lacteocrumenasia). The etiology of the accumulated substance and the method of
treatment are different in each type. CONCLUSION: Capsular block syndrome is a
complication of cataract/IOL surgery that can occur during and after surgery.
Correctly identifying the type of CBS is crucial to understanding the nature and
effective treatment of this disorder.
PMID- 9768399
TI - Measuring the anterior capsule opening after cataract surgery to assess capsule
shrinkage.
AB - PURPOSE: To measure anterior capsule opening (ACO) size after acrylic intraocular
lens (IOL) implantation and study the natural course of ACO reduction. SETTING:
Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan. METHODS: This study
comprised 32 patients (38 eyes) having continuous curvilinear capsulorhexis,
phacoemulsification, acrylic IOL implantation, and a self-sealing incision
performed by 1 surgeon. A retroillumination photograph of the ACO was obtained
with the Anterior Eye Segment Analysis System and converted to a computer image.
The images were used to measure ACO size postoperatively and calculate the
reduction ratio. Follow-up was 6 months. RESULTS: The postoperative reduction
ratio in ACO size was 2.14% at 1 week, 3.83% at 1 month, 4.29% at 3 months, and
5.03% at 6 months. In a few cases, the reduction was progressively severe
throughout the follow-up. CONCLUSIONS: The anterior capsule opening shrank
rapidly during the first month after acrylic IOL implantation, followed by a
slower progressive reduction in the subsequent 6 months. When severe, progressive
shrinkage occurs, an anterior neodymium:YAG laser capsulotomy should be performed
within 2 months postoperatively.
PMID- 9768400
TI - Effect of intraocular lens design on neodymium:YAG laser capsulotomy rates.
AB - PURPOSE: To compare the effect of 2 poly(methyl methacrylate) (PMMA), 1-piece
biconvex intraocular lens (IOL) designs on the cumulative frequency of
neodymium:YAG (Nd:YAG) laser posterior capsulotomy. SETTING: Department of
Ophthamology, Mayo Clinic, Rochester, Minnesota, USA. METHODS: This retrospective
study evaluated 369 eyes that had phacoemulsification with continuous curvilinear
capsulorhexis (CCC) and IOL implantation in the capsular bag. Patients were
placed in 1 of 2 groups based on the 1-piece, biconvex PMMA IOL design: large
IOL, with a lens diameter of 13.50 to 13.75 mm, optic size of 6.5 mm, and 10
degree haptic angulation; small capsular IOL, with a lens diameter of 12.0 to
12.5 mm, optic size of 5.5 mm, and 2 degree haptic angulation. RESULTS: Using
Kaplan-Meier analysis, the frequency of Nd:YAG laser posterior capsulotomy 1, 2,
and 3 years after cataract surgery was 1.6, 12.3, and 26.5%, respectively, in the
large IOL group and 3.4, 9.5, and 23.5%, respectively, in the small capsular IOL
group. The cumulative frequency of Nd:YAG laser capsulotomy was not statistically
different between the 2 groups. CONCLUSION: After phacoemulsification and CCC,
there was no significant difference in the Nd:YAG laser capsulotomy rate in eyes
with a small, capsular design, 1-piece, biconvex PMMA IOL and those with a
larger, angulated, 1-piece, biconvex PMMA IOL.
PMID- 9768401
TI - Effect of aspirin intake on bleeding during cataract surgery.
AB - PURPOSE: To study the association between chronic intake of aspirin and
intraoperative bleeding during cataract surgery and the effect of discontinuing
the medication before surgery. SETTING: Department of Ophthalmology, Meir
Hospital, Sapir Medical Center, Kfar-Saba, Israel. METHODS: Sixty-one patients
having cataract surgery and receiving aspirin to prevent thromboembolic events
were divided into 3 groups: Group A, continuation of the medication; Group B,
cessation of aspirin intake for 2 to 5 days before surgery; Group C, cessation of
medication for 7 to 10 days before surgery. Blood tests of coagulation
parameters, a detailed questionnaire, and 1 day and 1 week follow-up were
evaluated. RESULTS: There were no significant differences in blood tests and the
amount and incidence of intraoperative bleeding among the 3 groups. Diathermy was
used somewhat more in Group A; however, there was no difficulty stopping the
bleeding in any case and discontinuation of the medication had no effect on the
intraoperative course or postoperative outcome. CONCLUSIONS: Aspirin intake was
not associated with significant intraoperative bleeding; thus, discontinuation of
aspirin is usually not indicated. Clear corneal phacoemulsification is
advantageous in patients receiving antiplatelet therapy.
PMID- 9768402
TI - Topical plus subconjunctival anesthesia for phacotrabeculectomy: one year follow
up.
AB - PURPOSE: To evaluate the results of topical plus subconjunctival anesthesia for
phacotrabeculectomy surgery and postoperative glaucoma control over 1 year.
SETTING: Pacific Eye Center, Brisbane, Australia. METHODS: In this retrospective
study of consecutive patients with glaucoma and cataract, topical plus
subconjunctival anesthesia was used for combined phacoemulsification, posterior
chamber intraocular lens implantation, and trabeculectomy (phacotrabeculectomy).
Patients with proliferative diabetic retinopathy or neovascular glaucoma were
excluded. RESULTS: Thirty-eight eyes had phacotrabeculectomy using topical plus
subconjunctival anesthesia over 2 years. Patients reported no discomfort
intraoperatively or postoperatively, and none required intravenous sedation.
Eighty-one percent of patients achieved a best corrected visual acuity of 20/40
or better 6 months after surgery. Mean drop in intraocular pressure (IOP) was
5.91 mm Hg at 3 months and 5.86 mm Hg at 12 months, at which time IOP was
controlled without additional medication in 72% of patients. There were no
serious complications postoperatively. CONCLUSION: In this series, no patient
reported intraoperative or postoperative discomfort and surgical results were
excellent in terms of visual outcome and IOP control.
PMID- 9768403
TI - Phacofracture versus phacoemulsification in eyes with age-related cataract.
AB - PURPOSE: To compare manual phacofracture and phacoemulsification techniques.
SETTING: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi, India.
METHODS: This prospective, randomized study comprised 60 cases of age-related
cataract randomly divided into 2 groups: 30 eyes had phacoemulsification and 30,
manual phacofracture using a trisection technique. Postoperative evaluation was
at 1 day, 1 and 6 weeks, and 3 months. The parameters evaluated were amounts of
viscoelastic material and irrigating fluid used, the time required to manage the
nucleus, postoperative best corrected visual acuity, endothelial cell loss, and
complications. RESULTS: Mean viscoelastic material used intraoperatively (3.69 mL
+/- 0.81 [SD] versus 1.76 +/- 0.54 mL) and the time required to manage the
nucleus (7.78 +/- 2.07 minutes versus 2.53 +/- 1.18 minutes) were significantly
greater in the phacofracture than in the phacoemulsification group, respectively.
Best corrected visual acuity was significantly better in the phacoemulsification
group on the first postoperative day; 64% had a visual acuity of 6/9 or better
versus 37% in the phacofracture group. Endothelial cell loss at 3 months was
17.66 +/- 3.65% in the phacofracture group and 12.03 +/- 3.06% in the
phacoemulsification group and central corneal edema persisting for more than 1
week, 7 and 0 cases, respectively. The differences between groups were
statistically significant. CONCLUSION: More experience in and further
modification of the manual phacofracture technique are required before it can be
recommended as a safe alternative to phacoemulsification.
PMID- 9768404
TI - Metallic fragment deposits during phacoemulsification.
AB - PURPOSE: To describe the nature and origin of foreign metallic intraocular bodies
appearing after phacoemulsification. SETTING: Department of Ophthalmology,
University Hospital of San Juan, Alicante, Spain. METHODS: Two metallic
particles, 1 extracted during surgery and the other from a patient in whom
surgery had been performed, were studied by scanning electronic microscopy and X
ray dispersive energy spectroscopy. Also evaluated were all metallic elements
used in phacoemulsification including phaco tips, Sinskey hooks, and handpieces.
A morphologic analysis at various magnifications was performed and the
composition of the elements studied. RESULTS: Scanning electronic microscopy
showed irregularities of the phaco tip and Sinskey hook after their use.
Spectrographic analysis found that the phaco tip was mainly aluminum and
titanium; the Sinskey hook, iron, chromium, cobalt, and nickel; the handpiece,
iron, chromium, and nickel; and the 2 metallic particles, iron, chromium, and
nickel, the same as the handpiece. CONCLUSION: The metallic particles extracted
corresponded to those of the phaco handpiece. Vibration during prolonged use of
the phacoemulsifier probably caused these particles to chip off the handpiece.
PMID- 9768405
TI - Immunolocalization of prolyl 4-hydroxylase in rabbit lens epithelial cells.
AB - PURPOSE: To localize the enzyme prolyl 4-hydroxylase in the crystalline lens and
determine the ability of lens epithelial cells (LECs) to synthesize procollagen.
SETTING: Research laboratory, Department of Ophthalmology, Wakayama Medical
College, Wakayama, Japan. METHODS: Phacoemulsification and aspiration of the
crystalline lens followed by implantation of a poly(methyl methacrylate)
intraocular lens (IOL) were performed in 1 eye each of 6 albino rabbits; the eye
was enucleated 1 or 2 months later. Crystalline lenses were also extracted from
the eyes of 2 rabbits. These samples were processed for immunohistochemical
detection of the alpha- and beta-subunits of prolyl 4-hydroxylase. RESULTS: A
monolayer of LECs was detected on the inner surface of the intact anterior
capsule. Antibodies directed against both subunits of prolyl 4-hydroxylase
reacted strongly to LECs proliferating on capsules with IOLs, whereas little or
no reaction was observed in quiescent LECs or in the regenerated lenticular
structure. CONCLUSION: The presence of prolyl 4-hydroxylase in LECs proliferating
on the inner surface of the lens capsule suggests that these cells are involved
in the production of procollagen and fibrosis during capsular injury and repair.
Suppression of prolyl 4-hydroxylase activity may prevent the capsule
opacification that results from cataract removal and IOL implantation.
PMID- 9768406
TI - Immunolocalization of hyaluronan and CD44 in quiescent and proliferating human
lens epithelial cells.
AB - PURPOSE: To investigate the role of hyaluronan and its receptor CD44 in capsular
repair, their localization in opacified human posterior capsules and in lens
epithelial cells (LECs) was assayed. SETTING: Research laboratory, Department of
Ophthalmology, Wakayama Medical College, Japan. METHODS: In 8 patients, circular
sections of the anterior capsules obtained during cataract surgery, the extracted
crystalline lens, and the opacified lens capsules resulting from intraocular lens
implantation were examined immunohistochemically to detect hyaluronan or CD44.
RESULTS: Both hyaluronan and CD44 were found in the extracellular matrix that
accumulated on the inner surface of the capsular bags. In contrast, LECs
exhibited immunoreactivity to CD44 but not to hyaluronan. CONCLUSIONS: The cell
surface antigen CD44 was expressed ubiquitously by LECs. Expression of its ligand
hyaluronan by proliferating LECs suggests that this glycosaminoglycan may be
important in the development of posterior capsule opacification.
PMID- 9768407
TI - Pupillary block after pupillary capture of an AcrySof intraocular lens.
AB - A 54-year-old man developed pupillary block resulting from pupillary capture 2
months after uneventful phacomulsification and AcrySof intraocular lens (IOL)
implantation. The IOL was placed in the bag through a 6.0 mm continuous
curvilinear capsulorhexis. The glaucoma was treated with intravenous drip
infusion of a hyperosmotic diuretic, followed by peripheral iridectomy,
iridocapsular synechiolysis, and IOL repositioning. The IOL loops were located
completely in the bag. However, pupillary capture recurred 3 weeks after the
surgery, at which time intraocular pressure was normal. The flexibility of the
IOL optic and its large overall length and rigid, low-angulated loops were the
probable causes for the recurrence of the pupillary capture. The IOL was
exchanged for a sulcus-fixated, single-piece poly(methylmethacrylate) lens with
10 degree angulated loops. Pupillary capture did not recur during the follow-up.
PMID- 9768408
TI - Silicone intraocular lens encapsulation by shrinkage of the capsulorhexis
opening.
AB - We report a case of an 80-year-old woman who developed complete opacification and
contraction of the continuous curvilinear capsulorhexis opening 4 months after
having phacoemulsification and implantation of a silicone plate-haptic
intraocular lens. We performed a neodymium:YAG laser capsulotomy without
complication.
PMID- 9768409
TI - Interface keratitis-induced stromal thinning: an early postoperative complication
of laser in situ keratomileusis.
AB - Two patients had bilateral laser in situ keratomileusis on the same day at the
same center. Both developed severe interface inflammation in the second of the 2
eyes treated, which led to stromal thinning corneal haze, and resultant
hyperopia. These symptoms partially resolved over 7 weeks of follow-up.
PMID- 9768410
TI - Keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy.
AB - Endophthalmitis after keratotomy is rare and usually occurs soon after surgery. A
56-year-old woman with mild dry-eye symptoms developed keratitis complicated by
endophthalmitis 3 years after astigmatic keratotomy (AK). The keratitis lasted
for less than 1 day in the upper keratotomy incision. Corneal cultures yielded.
Pseudomonas aeruginosa. Keratitis progressed to endophthalmitis 1 day after the
detection of keratitis. The inflammation was controlled with intravitreal,
subconjunctival, topical, and systemic antibiotics. This case demonstrates the
potential risk of endophthalmitis developing very shortly after late keratitis of
AK incisions. Vigorous early treatment and close follow-up seem justifiable in
any keratitis associated with a keratotomy incision.
PMID- 9768411
TI - Toluidine blue: proceed with caution?
PMID- 9768412
TI - Pretherapy dental decisions in patients with head and neck cancer. A proposed
model for dental decision support.
AB - OBJECTIVE: The proposed model was designed to function as a tool for the
development and testing of evidence-based clinical guidelines for the pretherapy
oral screening and dental management of patients with head and neck cancer. STUDY
DESIGN: Methods of clinical decision analysis were used to analyze the decision
dilemma and construct a decision algorithm and decision tree. The robustness of
the model was tested by means of a probabilistic sensitivity analysis with second
order Monte Carlo simulations (n = 10.000). RESULTS: Clinical criteria for
evaluating dental pathologic conditions and malignancy- and patient-related
conditions were transformed in probability estimates. The tradeoffs between the
benefits and drawbacks of the dental intervention were integrated into the model
to identify the optimal option for dental intervention. The calculation process
of "folding back and averaging out" the decision tree enabled the identification
of the optimal options for dental intervention in four different pretherapy risk
conditions. CONCLUSIONS: A priori testing of the proposed model with 95%
confidence intervals suggests that it has a great potential for solving clinical
dilemmas associated with pretherapy dental decision-making. In addition, it seems
a useful tool for the development of evidence-based clinical guidelines. A
posteriori clinical testing should further validate the model before its
assimilation into clinical practice takes place.
PMID- 9768413
TI - Importance of bone graft quality for implant integration after maxillary sinus
reconstruction.
AB - OBJECTIVE: The aim of this study was to determine whether bone quality, as
assessed by osteometry and histologic parameters, can be used to predict implant
integration in conjunction with maxillary sinus reconstruction. STUDY DESIGN:
Twelve patients with severely atrophied maxillary alveolar processes were treated
through use of a two-stage surgical reconstructive strategy with implant
placement 4 months after bone grafting. Bone biopsy specimens taken from the
iliac crest peroperatively and from the sinus inlay sites 1, 2, 4, 6, or 12
months postoperatively were analyzed by light microscopy and osteomorphometry.
Bone mineral content was measured by osteometry. RESULTS: Osteometric and
osteomorphometric data (trabecular bone volume [%], assessment of chromatin
staining, and an osteocyte index) registered for the biopsy specimens were not
statistically correlated with implant failure. CONCLUSIONS: Prognostic evaluation
of implant survival is difficult. The tested methods did not contribute to the
improvement of guidelines for the clinical handling of these patients.
PMID- 9768414
TI - Comparison of magnetic resonance imaging and gross findings regarding masseter
muscle aponeuroses in cadavers.
AB - OBJECTIVES: The main objective of this study was to compare the actual
distribution and thickness of aponeuroses in cadavers with the distribution and
thickness as determined by means of magnetic resonance imaging for the sake of
evaluating magnetic resonance imaging as a diagnostic modality for assessing
masseter muscle aponeuroses. STUDY DESIGN: The aponeuroses of 26 masseter muscles
from 13 intact cadavers were examined by magnetic resonance imaging. RESULTS: The
ratio of concordance between gross findings and magnetic resonance imaging
findings was 99.0%, although depiction of thin parts of the aponeuroses on
magnetic resonance imaging was poor. CONCLUSIONS: Magnetic resonance imaging was
useful as a diagnostic modality in the assessment of masseter muscle aponeuroses.
Aponeuroses were distributed throughout almost the entire masseter muscle,
although almost no aponeuroses were seen below the lower half of the anterior
margin. This was thought to be a characteristic finding of masseter aponeuroses.
PMID- 9768415
TI - Mandibular height asymmetry following experimentally induced temporomandibular
joint disk displacement in rabbits.
AB - OBJECTIVE: The purpose of this study was to test the hypothesis that nonreducing
disk displacement of the temporomandibular joint causes mandibular asymmetry.
STUDY DESIGN: Unilateral anterior temporomandibular joint disk displacement with
intact posterior disk attachment was surgically created in the right joints of
seven growing rabbits. In each of seven sham animals, the right temporomandibular
joint was surgically opened without any disk manipulation. Seven animals served
as references. For identification of ramal growth and inferior growth at the
mandibular base, tantalum implants were inserted into the mandibular body.
Lateral cephalograms were exposed repeatedly throughout the 3-month investigation
period. Kruskal-Wallis one-way analysis of variance was used to compare the
groups. RESULTS: Compared with the sham and reference groups, the experimental
group exhibited a deviant growth pattern, with inferiorly directed growth along
the mandibular base and in the gonial area. The ramal height was significantly
shorter on the side with disk displacement. No significant side difference was
present in the sham and reference groups. CONCLUSIONS: Disk displacement can
cause mandibular asymmetry in growing rabbits, including shortening of the
mandibular ramus and excessive inferiorly directed bone growth along the lower
border of the mandible.
PMID- 9768416
TI - The relationships among fluoride, cariogenic oral flora, and salivary flow rate
during radiation therapy.
AB - Changes in the quantity of Streptococcus mutans, Lactobacillus species, and yeast
Candida species were assessed in a cancer population undergoing head and neck
radiation. The purpose of this study was to evaluate the effectiveness of a
custom vinyl tray-applied fluoride gel to control cariogenic bacteria in a group
experiencing hyposalivation because of radiation treatment. Twenty-two subjects
participated in the study and served as their own controls. Whole resting and
whole stimulated saliva were collected at weekly appointments beginning 1 week
before and concluding 4 weeks after radiation therapy. Colony-forming units per
mL of Streptococcus mutans and Lactobacillus species and semiquantitative counts
of Candida species (0 = none; 1 = light; 2 = moderate; 3 = heavy) were determined
from collected saliva. All patients were provided with custom vinyl vacuform
mouthguards to be used daily with neutral fluoride gel (1.1% sodium fluoride).
Whole stimulated and resting saliva productions decreased by 36.67% and 47.9%,
respectively, by the end of 1 week of radiation therapy, and they remained low.
No significant changes in cariogenic oral flora were seen during and early after
radiation therapy, despite xerostomia. However, colonization by Candida albicans
increased during radiation therapy for oropharyngeal cancers. Findings from this
study suggest that changes in cariogenic flora may be suppressed through the use
of daily topical neutral sodium fluoride gels and that colonization by Candida
albicans increase during radiation therapy.
PMID- 9768417
TI - Bell's palsy associated with herpes simplex gingivostomatitis. A case report.
AB - Bell's palsy is a sudden, isolated, peripheral facial paralysis caused by various
known and sometimes unknown factors. The case of an 18-year-old man who developed
Bell's palsy after onset of primary herpetic gingivostomatitis is presented.
Although Bell's palsy has already been associated with herpes simplex virus type
1, the described case is the first in the literature in which enzyme-linked
immunosorbent assays for immunoglobulin G to herpes simplex virus type 1 and
herpes simplex virus type 1 culture were both positive. The recent literature
regarding the possible relationship between herpes simplex virus type 1 and
Bell's palsy is reviewed and discussed.
PMID- 9768418
TI - Dento-maxillofacial sequelae in a child treated for a rhabdomyosarcoma in the
head and neck. A case report.
AB - This case report describes severe dento-maxillofacial defects after
chemoradiation therapy in a child aged 9 years 6 months with a parameningeal
rhabdomyosarcoma. A clinical and radiologic (apical dental radiographs,
orthopantograph, lateral skull roentgenogram) dental follow-up over 4 years
showed such dental abnormalities as root blunting, mild to severe root
shortening, premature closure of the root apices, and severe radiation caries.
Craniofacial morphology evaluated by cephalometric analysis and dental models
showed deficiency with mandibular and maxillary hypoplasia.
PMID- 9768419
TI - Gingival fibromatosis with prune-belly syndrome.
AB - A case is described in which a child appeared for evaluation with marked gingival
overgrowth, facial dysmorphism, and abdominal defects consistent with prune-belly
syndrome. The relationship between this case and other reports of gingival
enlargement are discussed. Coincidence of the oral, facial, and abdominal
abnormalities has not been previously reported.
PMID- 9768420
TI - Caliber-persistent labial artery. A common vascular anomaly.
AB - Sixteen cases of caliber-persistent labial artery of the lips have been reported
to date in the English literature. Six of these were clinically misdiagnosed as
squamous cell carcinoma and treated with wedge resection. To date, we have seen
187 cases clinically and an additional 23 cases through our surgical oral
pathology services. Careful clinical observation usually reveals a soft linear or
papular bluish elevation above the labial mucosal surface. The unique feature is
pulsation--not simply pulsation toward and away from the observer, which can be
caused by an underlying artery, but lateral pulsation, which only an artery can
exhibit. All but 2 of our 187 clinical cases were asymptomatic. To the best of
our knowledge, this is the first report of caliber-persistent labial artery of
the upper lip. The upper:lower lip ratio for the clinical cases was almost 2:1.
Three times as many lower lip as upper lip lesions were biopsied. Males and
females were almost equally affected (clinical cases, 76:86; histopathologic
cases, 9:13). Although a vascular term (artery, hemangioma, phlebolith, varix,
vascular malformation) was used on the biopsy form in one half of the clinical
differential diagnoses, none of the clinical histories mentioned pulsation. In
contrast to the cases of Miko et al. in 1980 and 1983, none of our cases
manifested itself as an ulcer, nor was carcinoma ever mentioned in the clinical
differential diagnosis. The purpose of this article is to familiarize clinicians
and pathologists with the clinical and histopathologic features of this seldom
reported but common vascular anomaly. Clinicians should carefully look for
lateral pulsation in lip mucosal papules so as to avoid unnecessary surgery and
intraoperative arterial bleeding. Pathologists should recognize that a relatively
large-caliber superficial artery in a lip biopsy may not be an incidental finding
but rather the clinical lesion that was biopsied.
PMID- 9768421
TI - Adenomatoid dentinoma. Report of four cases of an unusual odontogenic lesion.
AB - Four cases of a rare odontogenic lesion are reported. In each of the 4 examples,
the lesion manifested itself as a well-circumscribed unilocular radiolucency in
the mandibular third molar region in an adult. The histopathologic features
consisted of an encapsulated proliferation of odontogenic hard and soft tissues.
The hard tissue component consisted of dentin deposited in a peripheral ringlike
configuration that enclosed odontogenic epithelium resembling adenomatoid
odontogenic tumor. Whether this process represents a neoplasm or an odontogenic
hamartoma is an unresolved question. Treatment in each case consisted of
curettage, and no recurrences were observed.
PMID- 9768422
TI - Oral verrucous carcinoma. Incidence in two US populations.
AB - Much is known about the clinical appearance, biological behavior, and treatment
of verrucous carcinoma of the oral cavity. However, the epidemiologic
characteristics are completely unknown. This cancer is considered to be rare in
Western cultures because it is not common in oral pathology biopsy services, but
there is no epidemiologic evidence for this belief. To provide this evidence, 2
population-based incidence investigations were carried out, one in Rochester,
Minn., and the other in the state of West Virginia. The results were as follows:
the age-adjusted average annual incidence rate for oral verrucous carcinoma among
Rochester residents was 0.1/100,000 person-years (0.2 for males, 0.0 for
females), whereas the incidence rate for all intraoral carcinomas was 3.6/100,000
person-years (5.4 for males, 2.1 for females). Among men over 64 years of age,
the incidence rate for verrucous carcinoma was increased to 3.2/100,000 person
years. Verrucous carcinoma was among the least common of the oral carcinomas in
this population, representing only 3% of the total. The age-adjusted incidence
rate for oral and pharyngeal verrucous carcinoma among West Virginia residents
was somewhat greater, 0.3/100,000 person-years, and showed an even gender
predilection (0.28 for males, 0.29 for females). The incidence rate for all
oral/pharyngeal cancers in West Virginia was 8.8/100,000 person-years (13.4 for
males, 5.7 for females), which was below the US average. The conclusion is that
oral verrucous carcinoma is a rare tumor of older people, diagnosed in only 1 to
3 of every 1,000,000 persons each year.
PMID- 9768423
TI - Radiotherapy for cancer of the lip. A long-term evaluation of 85 treated cases.
AB - The results of radiation therapy, both as a single treatment modality and after
radical surgery for squamous cell carcinoma of the vermilion surface/border of
the lip, are retrospectively analyzed in 85 patients. All recurrences (7%)
occurred in T2 and T3 tumors treated with external beam radiotherapy only. The
long-term esthetic result and functional morbidity are evaluated. Referral
patterns are discussed, and the need for a multidisciplinary treatment protocol
is emphasized.
PMID- 9768424
TI - Status of the specialty of oral and maxillofacial pathology, 1997.
PMID- 9768425
TI - Nonsurgical root canal therapy treatment with apparent indications for root-end
surgery.
AB - The recent introduction of the surgical microscope to the practice of
endodontics, especially for surgery, has allowed clearer visualization of the
periapex during root-end resection and filling. However, despite this and other
technologic advances, it has not been demonstrated that in the absence of
thorough canal debridement the success rate of periapical surgery has improved
over the 50% to 60% demonstrated in most long-term prognosis studies. Therefore
it remains important to fully instrument and obturate the root canal system with
conventional therapy before surgery is considered; this considerably improves the
long-term prognosis. Each of the case reports in this article involves a
situation in which conventional treatment was performed when a surgical approach
might have been considered as the treatment of choice. Surgery should not be
considered to be the primary treatment when root canal treatment or retreatment
may be readily achieved. Indeed, the operating microscope and other technical
aids will probably allow more cases to be treated and retreated conventionally
that might otherwise have required surgical intervention.
PMID- 9768426
TI - Morphologic effects on L929 fibroblasts of titanium tetrafluoride application.
AB - OBJECTIVE: The aim of this study was to investigate the effect of titanium
tetrafluoride solution on L929 fibroblasts by scanning electron microscopy.
Titanium tetrafluoride was then compared with sodium fluoride and acidulated
phosphate fluoride. STUDY DESIGN: Cells were treated with fluoride solutions for
1 minute either directly, through a filter membrane with a pore size of 0.4
micron, or indirectly, through dentin disks; they were then investigated at an
electron microscopic level. RESULTS: Fluoride application on smeared dentin disks
showed fewer cytotoxic effects on fibroblasts than application on nonsmeared
dentin disks. Acidulated phosphate fluoride and titanium tetrafluoride appeared
to be more cytotoxic than sodium fluoride. Because all fluoride solutions used in
this study contained the same fluoride concentration, pH was considered to be the
main factor causing the higher toxicity. CONCLUSION: Because these solutions
demonstrated toxicity in vitro, they must be further evaluated under in vivo
conditions to ascertain their clinical safety.
PMID- 9768427
TI - Dens invaginatus. Review of formation and morphology with 2 case reports.
AB - Dens invaginatus manifests itself with an aberrant morphologic character because
of altered patterns of tooth formation. Presented in this article are 2 cases of
dens invaginatus in maxillary lateral incisors that were successfully treated
nonsurgically. In the first case, a circular main canal was clearly observed
surrounding the invaginated canal. The involved tooth in the second case
responded to electric pulp testing, though a periapical radiolucency was evident;
root canal treatment of the invaginated canal failed to resolve the pathosis.
Debridement of both the main canal and the invaginated canal produced resolution.
The complex morphologic nature of these root canal systems and the close
relationship between the invaginated and main canals is demonstrated and
discussed.
PMID- 9768428
TI - A study of the impact of screening or selective radiography on the treatment and
postdelivery outcome for edentulous patients.
AB - OBJECTIVE: The purpose of this study was to assess the impact of radiographic
findings on complete denture treatment and on the postdelivery course of those
patients who had pretreatment radiographs (the screening group) and those who did
not (the selection group). METHOD: In total, 375 cases were randomly selected by
systematic sampling. Data collected included patient demographic information and
denture history, predenture fabrication radiographic findings, and postdenture
delivery complaints. RESULTS: Of the screening patients, 100% had pretreatment
radiographs made; this compared with 13.5% of the selection patients. In the
screening group, 68.3% of patients had one or more positive radiographic findings
recorded. Of the screening patients, 8.3% received treatment before denture
fabrication; this compared with 1.2% of the selection patients. Of the 375 cases,
2 screening patients had postdelivery complaints that required management other
than denture adjustment. CONCLUSION: The results indicate that there is weak
scientific support for the guideline recommending routine pretreatment
radiography for new denture patients.
PMID- 9768429
TI - Landmark identification error in submentovertex cephalometrics. A computerized
method for determining the condylar long axis.
AB - The purpose of this study was to examine the identification error of certain
submentovertex landmarks and to compare three different methods of determining
horizontal condylar angulation in submentovertex radiographs. To determine
landmark identification error, a random sampling of 12 submentovertex radiographs
from preorthodontic patients between the ages of 10 and 17 years was used to
determine both intraexaminer and interexaminer reliability. The error associated
with the identification of each of 11 landmarks varied between specific
landmarks, between the same landmarks bilaterally, and between the vertical and
horizontal components of the same landmark. In general, intraexaminer data showed
less landmark identification error in both vertical and horizontal directions
than did interexaminer data. The foramen spinosum landmarks demonstrated the
lowest identification error in both horizontal and vertical direction
(intraexaminer), whereas greater identification error was associated with the
condylar lateral poles and posterior condylar points (both intraexaminer and
interexaminer). A comparison of three different methods of condylar angulation
determination was undertaken through the use of two tracings of each of 101
submentovertex radiographs. A computer-derived method representing the principal
axis of minimum moment of inertia of the condyle was shown to be more reliable (p
< 0.05) with respect to describing condylar angulation than both a method that
used a best-fit line through the anterior condylar border and an interpolar axis
method.
PMID- 9768430
TI - A reliability comparison of submentovertex and zonographic methods of horizontal
condylar angle estimation.
AB - OBJECTIVE: The objectives of this retrospective clinical study were, first, to
compare submentovertex radiography and zonographic temporomandibular joint
orientation programs that use the Scanora imaging system with respect to the
reproducibility with which the angulation of the horizontal condylar axis may be
determined and, second, to assess the level of agreement between the 2 methods.
STUDY DESIGN: Submentovertex radiographs and zonographic projections of 16 joints
(8 patients) were evaluated. Two raters independently determined the horizontal
angulation of each condyle 3 times using each method. Horizontal condylar angle
measurements differing by no more than 5 degrees were considered to be in
agreement. Statistical analyses were performed with a repeated-measures analysis
of variance, sign tests, and Wilcoxon signed rank test. RESULTS: No significant
difference was found in the 3 measurements between the 2 raters (P = .9122) or
between the raters adjusted for method (P = .5093). A significant difference was
found between methods (P = .0001). Intrarater agreement values were 81% and 88%
for the submentovertex method and 75% for each rater for the zonographic method.
Interrater agreement was 94% for each method. Intermethod agreement was 50% for
one rater and 81% for the other. CONCLUSIONS: The submentovertex and zonographic
methods of determining the horizontal condylar angulation demonstrated
consistency and reliability both within and between the raters. However, the
zonographic method did not agree with the submentovertex method. This findings
does not imply that the zonographic is not a clinically acceptable technique for
the determination of the horizontal condylar angulation when subsequent
tomographic projections are made on the same unit with the same head-positioning
device.
PMID- 9768431
TI - Gross periostitis ossificans in mandibular osteomyelitis. Review of the English
literature and radiographic variation.
AB - OBJECTIVE: The purpose of this study was to describe a radiographic variety of
gross periostitis ossificans in mandibular osteomyelitis and to determine what
types of gross periostitis ossificans are related to a specific form of
mandibular osteomyelitis without demonstrable causes. STUDY DESIGN: We reviewed
20 cases of gross periostitis ossificans in patients with mandibular
osteomyelitis that had been reported with illustrations in the English
literature, and we reviewed our own 14 cases of gross periostitis ossificans,
previously reported. The radiographic features of the 34 cases of gross
periostitis ossificans were classified according to the status of original
contour and the appearance of gross periostitis ossificans. Histopathologic
features were studied in 12 cases. RESULTS: The 34 cases of gross periostitis
ossificans could be classified radiographically into 4 types. Type A, showing an
"onion-skin" appearance, was caused by a carious tooth or followed extraction of
a tooth. Type B and type C showed a consolidation form; in the 36.8% (7/19) of
these cases in which no infectious source could be identified, it was suspected
that the condition was caused by a developing unerupted tooth or a dental
follicle. Type D was seen in the most chronic stage. Biopsy specimens of 12 cases
commonly showed proliferation of newly formed bone, loose interstitial fibrous
tissue, and a low-grade inflammatory cell infiltration. CONCLUSION: Gross
periostitis ossificans of type B or type C may be a specific form of mandibular
osteomyelitis without demonstrable cause.
PMID- 9768432
TI - Acute renal failure--which treatment modality is the best?
AB - Despite the progress in animal research concerning the pathophysiology and the
progress in clinical practice regarding the methods of therapy, the incidence and
mortality of acute renal failure remain high, especially when other organs are
involved. New pharmacological interventions have led to the perspective that in
the near future it may be possible to prevent and/or ameliorate this devastating
syndrome. Continuous dialysis therapy and the selection of a biocompatible
membrane may possibly help the critically ill patient especially when parenteral
nutrition and correction of electrolyte and acid-base disturbances are important.
Nevertheless, more solid data are needed and one should take into consideration
that acute renal failure is a multifactorial syndrome. The type of dialysis
itself is not the only matter which has to be evaluated since the mortality rate
can be correlated with the number of involved organs before or after the
initiation of acute renal failure and with the severity of the original disease.
In clinical practice, a large number of prospective studies and more
sophisticated statistical methodology are needed in order to evaluate the proper
treatment modality.
PMID- 9768433
TI - Vascular contributions to pathogenesis of acute renal failure.
PMID- 9768434
TI - Proteases in renal cell death: calpains mediate cell death produced by diverse
toxicants.
AB - The role of proteases in renal cell death has received limited investigation.
Calpains are non-lysosomal cysteine proteases that are Ca+2 activated. Calpain
inhibitors that block the active site of calpains (calpain inhibitor 1 and 2) or
the Ca+2 binding domain of calpains (PD150606) decreased calpain activity in
rabbit renal proximal tubule (RPT) suspensions. The inhibition of calpain
activity decreased cell death produced by the diverse toxicants antimycin A
(mitochondrial inhibitor), tetrafluroethyl-L-cysteine (nephrotoxic halocarbon),
bromohydroquinone (nephro-toxic quinone), t-butylhydroperoxide (model oxidant)
and ionomycin (Ca+2 ionophore). In summary, calpains appear to play a common and
critical role in cell injury produced by diverse toxicants with different
mechanisms of action. The general cysteine protease inhibitor trans-epoxysuccinyl
L-leucylamido (4-guanidino)-butane (E-64) decreased antimycin A- and
tetrafluoroethyl-L-cysteine-induced cell death but had no effect on
bromohydroquinone- or t-butylhydroperoxide-induced cell death. Serine/cysteine
protease inhibitors (antipain, leupeptin) were not cytoprotective to RPT exposed
to any of the toxicants. The cytoprotection associated with E-64 correlated with
inhibition of lysosomal cathepsins and E-64 was only cytoprotective after some
cell death had occurred. Since some cell death occurred prior to the E-64
cytoprotective effect, lysosomal cathepsins may be released from dying cells and
subsequently target the remaining viable cells.
PMID- 9768435
TI - The nephrotoxicity of new and old immunosuppressive drugs.
AB - The above snapshot of the relevant literature on chronic Cyclosporine and
Tacrolimus nephropathy indicate fertile areas for further study. The reader is
referred to recent reviews for a more in-depth analysis of this problem (2).
PMID- 9768436
TI - Update on clinical trials with atrial natriuretic peptide in acute tubular
necrosis.
PMID- 9768437
TI - The roles of apoptosis in uranyl acetate-induced acute renal failure.
PMID- 9768438
TI - Early glomerular effects of contrast media in rats: evaluation with a simple
method.
AB - The aim of this study was to evaluate the early effects of high and low-osmolar
contrast media on glomerular function in rats by using a new method based on the
measurement of the urinary excretion of 99mTc-DTPA. Thirty-six Sprague-Dawley
male rats were examined: nine rats were injected with diatrizoate (ionic high
osmolar contrast medium), nine rats with iohexol (nonionic low-osmolar contrast
medium), and nine rats with saline as controls. The urinary excretion of 99mTc
DTPA in the first minutes after i.v. injection was assumed as an index of
glomerular filtration rate. A lower urinary excretion of 99mTc-DTPA was found in
rats treated with contrast media in comparison with control rats. This effect was
more evident after diatrizoate but was statistically significant also after
iohexol. In conclusion, a reduction in the glomerular filtration rate probably
occurs in the first few minutes after contrast media administration. The
measurement of urinary excretion of 99mTc-DTPA could be a simple method to detect
acute glomerular effects due to contrast media or to other drugs.
PMID- 9768439
TI - Urinary excretion of proteins and tubular enzymes in renal transplant patients.
AB - The aim of this study was to evaluate, in renal transplant recipients with
different function of the graft, the urinary excretion of some low molecular
weight proteins and tubular enzymes frequently employed as indicators of tubular
dysfunction. Urinary excretion of proteins and enzymes was measured in 51 renal
transplant patients and, for comparison, in 73 patients affected by different
kidney diseases with various degrees of renal function. Values of urinary beta 2
microglobulin and retinol-binding protein higher than normal were found in most
transplanted patients, even in those with good renal function. On the other hand,
in renal patients the urinary excretion of low molecular weight proteins was high
only when creatinine clearance was lower than 30 mL/min/1.73 m2. Furthermore, an
increased urinary excretion of tubular enzymes was found in a higher number of
transplanted patients than of renal patients. This behavior was particularly
evident for lysosomal enzyme N-acetyl-beta-D-glucosaminidase. In conclusion, a
tubular dysfunction occurs in the transplanted kidneys, even in those with well
preserved glomerular function.
PMID- 9768440
TI - Atrial natriuretic peptide as a preload depressor in acute renal failure
secondary to congestive heart failure.
AB - The present study was undertaken to verify the hypothesis that infusion of atrial
natriuretic peptide (ANP) might lower preload and be beneficial in the treatment
of pulmonary congestion even without a diuresis in patients with acute renal
failure (ARF) secondary to severe congestive heart failure (CHF). We studied 22
patients with ARF secondary to CHF. The mean age of the patients (14 men and 8
women) was 72 years (range 36 to 85 years). Seven of the patients had dilated
cardiomyopathy, ten had ischemic heart disease, and five had valvular heart
disease. ANP was infused intravenously and the following data before and 1 hour
after the start of ANP infusion were recorded; urinary output, systemic blood
pressure (SBP), pulmonary blood pressure (PBP), right atrial pressure (RAP),
cardiac index (CI), heart rate (HR), and arterial blood oxygen partial pressure.
Diastolic PBP were employed as pulmonary capillary wedge pressure. Urinary output
did not change. Mean SBP decreased from 92 to 85 mmHg (p < 0.05), and mean PBP
decreased from 34 to 28 mmHg (p < 0.01). Mean RAP decreased from 11 to 9 mmHg (p
< 0.01) and diastolic PBP decreased from 25 to 19 mmHg (p < 0.01). HR did not
change significantly and CI increased 2.4 to 2.5 mi/min/m2 (p < 0.05). Arterial
blood oxygen partial pressure increased significantly from 71 to 82 mmHg (p <
0.05). In conclusion, ANP decreased preload and improved arterial blood oxygen
partial pressure, though diuretic response to ANP is attenuated in ARF secondary
to CHE. Infusion of ANP will be very beneficial in cases in which dyspnea and
pulmonary edema due to elevation of preload are the principal clinical problems.
PMID- 9768441
TI - Prognosis in acute renal failure of septic origin: a multivariate analysis.
AB - The goal of the present study was to identify variables associated with the
outcome of patients with acute renal failure (ARF) of septic origin, using
multivariate analysis. The records of 168 patients were reviewed retrospectively
and a crude mortality of 74% was found. Both univariate as well as multivariate
analysis demonstrated an association between mortality and variables which
depended on patient related factors. These included age over 60 years and several
underlying diseases such as pneumonia, peritonitis, and organ dysfunction. Only
one variable (late oliguria) related to the ARF itself. Thus, outcome seems
related to underlying disease more than to severity of ARF.
PMID- 9768442
TI - Normotensive scleroderma renal crisis: case report and review of the literature.
AB - A 58 year old man presented with skin manifestations of scleroderma without
systemic involvement. Within few weeks of oral corticosteroids and penicillamine
therapy, rapidly progressive systemic sclerosis developed. The deterioration
manifested by skin lesions, diffuse interstitial restrictive lung disease, acute
renal failure with normal blood pressure values, and microangiopathic hemolytic
anemia compatible with hemolytic uremic syndrome. Chronic renal failure developed
and was treated by dialysis, but the patient died due to sepsis. The course of
renal involvement was normotensive; antihypertensive therapy was not prescribed
even once. The association of scleroderma renal crisis with normal blood pressure
is probably a rare and ominous combination.
PMID- 9768443
TI - A case of microscopic polyarteritis nodosa with interstitial pneumonia
successfully treated with steroid pulse therapy and immunosuppressive agents.
AB - We report a patient with microscopic polyarteritis nodosa (mPN) and interstitial
pneumonia, who was subjected to investigation by bronchoalveolar lavage (BAL),
thoracic computerized tomography (CT) and gallium-67 citrate (67Ga) scintigraphy
before and after administration of glucocorticoid and immunosuppressive agents.
Renal function, renal histology, interstitial inflammation of the lung, and
pulmonary function and histology improved cytoplasmic autoantibody (MPO-ANCA),
which decreased with decreasing disease activity after starting treatment.
Interstitial pneumonia may be associated with pulmonary capillaritis due to mPN.
Methylprednisolone pulse therapy followed by oral prednisolone and
immunosuppressive agents is considered to be an effective therapeutic strategy
for combined mPN and interstitial pneumonia.
PMID- 9768444
TI - Perinatal determinants of adult cardiovascular disease and cancer.
AB - Interest in perinatal factors, especially birthweight, as determinants of adult
onset diseases has been steadily growing. Low birthweight has been associated
with increased risk of cardiovascular disease, and high birthweight has been
linked to higher risk of breast and possibly other cancers. Most mechanistic
hypotheses that have been advanced to explain the empirical evidence linking
perinatal conditions to adult-life disease in humans have invoked modulation of
physiological processes by exogenous factors or poorly specified "programming"
during fetal life. A form of programming that has a strong biological foundation
and has recently been suggested for further study is genomic imprinting, which
involves non-permanent DNA modifications and allows for influences that span
three generations. The subject of the perinatal origin of adult-onset disease has
profound implications and a large and reliable body of evidence needs to be
assembled for biological theories to be validly evaluated against.
PMID- 9768445
TI - Use of a historical register in social epidemiology: child mortality in Stockholm
at the turn of the 19th century.
AB - This study describes the age- and cause-specific levels and social determinants
of high child mortality in Stockholm around the turn of the century. The study is
based on computerized individual level sociodemographic information and the death
certificates of children aged 0-15 years residing in Maria parish in Stockholm
during the years 1885, 1891 and 1910 (n = 36,718) from a historical register (the
Roteman archives). The usefulness of such data for further studies in social
epidemiology is discussed. Age-specific rates and major causes of death compared
well with other studies. Low social class and being born out of wedlock increased
the overall risk of death in early childhood. Data appear valid and may be useful
in social epidemiology. Further analyses of data from the Roteman archives may
contribute to the understanding of causes behind high levels of cause- specific
child mortality and trends in mortality in relation to societal change.
PMID- 9768446
TI - Review of social epidemiologic research on migrants' health: findings,
methodological cautions, and theoretical perspectives.
AB - The phenomenon of world-wide immigration and migration has major implications for
the health of the migrants in addition to its impact upon social and other
service providers. Studies of migrants that utilize social epidemiologic methods
fall within the traditional boundaries of descriptive and analytic approaches;
this article reviews some of the studies that exemplify these approaches. It then
suggests specific methodological issues and cautions pertaining to research on
migrants and provides a theoretical model for organizing the diverse research
studies that have been conducted. By stimulating discussion regarding social
epidemiologic research on migrants' health, this model is intended to serve as a
compass point for future research and needed interventions.
PMID- 9768447
TI - Planning a worksite health promotion program: health profile of a population of
Greek sailors.
PMID- 9768448
TI - Tobacco use and exposure to environmental tobacco smoke in relation to certain
work characteristics.
AB - This study aims to describe the prevalence of smoking, snuff use, and exposure to
environmental tobacco smoke (ETS) in relation to occupation among common female
and male workers in Sweden. The associations between shift work, job strain, and
tobacco use and exposure to ETS are assessed. The results are based on
questionnaire data of 2,584 men and 2,836 women randomly selected from 63
occupations in two counties in Sweden. The prevalence of smoking ranges from 10%
(95% CI 4.5-16%, police officers) to 42% (95% CI 29-55%, packing workers) in men,
and between 8% (95% CI 2-14%, dentists) and 51% (95% CI 37-65%, packing workers)
in women. Snuff use is more common among men (range 11-44% in different
occupations) than among women (range 0-7%). The prevalence of exposure to passive
smoking in this study ranges from 0.9% to 26% in men and from 0% to 30% in women.
Shiftwork is significantly associated with current smoking, and job strain is
significantly related to exposure to ETS. Ages between 18 and 29 years
experienced an increased risk of exposure to ETS compared to older age groups. In
conclusion, this study shows that tobacco use and exposure to ETS is still a
major problem in the Swedish workplace.
PMID- 9768449
TI - Differences in injury mortality between the Nordic countries--with special
reference to differences in coding practices.
AB - The aims of the study are to analyse the incidence and patterns in injury
mortality in the Nordic countries, and to assess the extent to which any
differences found can be explained in terms of either variation in statistical
validity or the existence of genuine differences. The study considers the entire
injury panorama, and is performed between certain categories of injuries.
Analysis is applied to all ages, and also to certain specific age categories.
Finland appears as the Nordic country with the highest injury mortality. While
examining potential source of errors, nothing was found to merit an adjustment of
Finland's rate. All potential correction would bring the rates of the other
Nordic countries closer to that of Finland. Poisoning was found to be a diagnosis
that varies in application between the Nordic countries. Falling is the diagnosis
with the greatest problems of sensitivity, and cannot be recommended for
comparative purposes.
PMID- 9768450
TI - Prevalence of intellectual dysfunctioning and its correlates in a community
residing elderly population.
AB - To examine the prevalence of intellectual dysfunctioning and its correlates in
community-residing elderly people, a randomly selected sample of 1,405 people
aged 65 and over living in Settsu, Osaka, were investigated in October 1992. Data
for assessing intellectual dysfunctioning were obtained from 1,364 people
(97.1%), excluding 21 clinically demented people (1.5%); 17.6/100, 5.6/100, and
3.3/100 of the population showed minor, moderate, and appreciable intellectual
dysfunctioning, respectively, and the prevalence of intellectual dysfunctioning
increased with age. By multivariate analyses using logistic regression, age over
75, poor general health, including current medical treatment, and psychosocial
conditions such as no participation in social activities, no life worth living
(no Ikigai), and anxiety about the future were independent risk factors for
intellectual dysfunctioning. We conclude that intellectual dysfunctioning is
closely associated with health and psychosocial conditions.
PMID- 9768451
TI - Gender trends in sick-listing with musculoskeletal symptoms in a Swedish county
during a period of rapid increase in sickness absence.
AB - Sickness absence and disability pension due to musculoskeletal diagnoses has
increased in Sweden. STUDY OBJECTIVE: To study gender trends in sickness absence
with musculoskeletal diagnoses and its changes in 1985-87. DESIGN: A prospective
population-based study of all new sick-leave spells exceeding seven days in 1985
87. Sickness absence with "all diagnoses" was compared to "all musculoskeletal
diagnoses", the latter group was also divided into three sub-groups. SETTING: The
county of Ostergotland, Sweden. PARTICIPANTS: All sick-leave insured aged 16-65;
107,000 women and 100,000 men. RESULTS: More women than men were sick-listed in
"all diagnoses" in 1985. There were corresponding gender differences in sickness
absence with musculoskeletal diagnoses except with the diagnosis "low back pain".
Sick-listing with musculoskeletal diagnoses increased for both women and men from
1985 to 1987, but the increase was consistently much higher for women, especially
for younger women.
PMID- 9768452
TI - Trend of psychological distress in a Swedish population from 1989 to 1995.
AB - The economic recession which began in Sweden in 1991 was followed by a large
increase in the unemployment rate, especially in the younger labour force. The
main purpose of the present study was to examine whether this recession has
resulted in an increase in psychological distress in the population. Self
reported symptoms of anxiety, anguish, depression and sleeplessness have been
analysed in repeated cross-sectional surveys conducted every other year from 1989
to 1995 in the County of Ostergotland. The study was confined to the 20-39 years
age group and includes 3122 male and 3440 female respondents. The analysis was
restricted to symptoms reported as occurring often or constantly. There was a
significant increase in the 12-month prevalence of psychological distress among
both men and women. At the beginning of the period 5% of the men in the 20-29
years age group reported frequent symptoms of psychological distress. By 1995
this had increased to 10%. The largest increase in prevalence, however, was found
in men in the 30-39 years age group and women in the 20-29 years group
Interestingly, when the non-employed groups were excluded from the analysis, the
increasing trends of reported distress remained statistically significant with
the exception of women aged 30-39 years.
PMID- 9768453
TI - Self-rated health among cardiovascular drug users in a study of Swedish twins.
AB - The aim of this study was to analyse the relationship between self-perceived
health and cardiovascular disease with and without drug treatment. Mental health
and genetic effects were controlled for in the analyses. The data for these
analyses were collected in 1984 as part of the Swedish Adoption/Twin Study of
Aging (SATSA). In the first set of analyses, 1147 persons (mean age 60 years, 72%
older than 50 years) were included. In the second part of the study, twin pairs
discordant with respect to having a cardiovascular disease and/or drug use were
included in the analyses. Cardiovascular disease was related to poor, self-rated
health among both men and women. The proportion with bad health was largest among
those with a drug-treated disease. In multivariate analyses, a strong
relationship between cardiovascular disease, drug therapy and low self-rated
health remained after controlling for mental health. The co-twin control analyses
indicate that cardiovascular drugs have at most a marginal negative effect on
health beyond the effects of the disease and genetic liability to self-perceived
poor health.
PMID- 9768454
TI - Doctors' attitudes to fibromyalgia: a phenomenological study.
AB - Besides specific technical skills, successful encounters with patients require an
understanding of the many ways in which patients may express themselves. This
qualitative study reports on the clinical experiences of doctors when meeting
patients with fibromyalgia (FM). Ten strategically chosen rheumatologists and 10
GPs in central Sweden were interviewed. The interviews were taped, transcribed
and analysed in accordance with the empirical, phenomenological, psychological
method. The analyses indicate that doctors try to comply with the wishes and
demands of patients, and at the same time avoid perceptions of personal
frustration. They are inclined to be objective and to act instrumentally,
apparently in order to keep in touch with what gave biomedical meaning to an
otherwise incomprehensible phenomenon. The meaning structures revealed by
doctors' descriptions of FM and of relating to FM patients were characterized
mainly by the way in which the doctors were (i) managing their clinical
uncertainty, (ii) adhering to the biomedical paradigm, (iii) prioritizing
diagnostics, (iv) establishing an instrumental relationship, and (v) avoiding
recognizing FM as a possible biomedical anomaly.
PMID- 9768455
TI - To sing in a choir and be healthy--which are the mediating mechanisms?
PMID- 9768456
TI - Tooth wear and temporomandibular joint morphology in a skull material from the
17th century.
AB - Skeletal remnants from the skulls of 69 subjects from the 17th century have been
studied focusing on TMJ morphology and tooth wear. Several of the skulls were
damaged and altogether 68 condyles and 28 temporal components of the TMJ, and 97
dentate jaws could be examined. Tooth wear was extensive and most of the first
molars in both jaws had lost most of their occlusal morphology. This is
remarkable with respect to the fact that the great majority of the subjects had
died before the age of 35 years, according to the age determination performed.
The TMJs showed frequent remodelling but only rarely deformative changes. The
frequent observation of a broken up compact bone layer on the condyle was
interpreted as a post-mortem artefact. The results indicate adaptive response of
the TMJs to the probably heavy masticatory function but do not support the
suggested relationship between tooth wear and TMJ osteoarthrosis.
PMID- 9768457
TI - Caries and periodontal conditions in patients with primary Sjogren's syndrome.
AB - The present investigation was designed to study caries and periodontal conditions
in a selected group of patients with primary Sjogren's syndrome (1oSS). Twenty
one patients, 20 females and 1 male aged 44-75 years (mean 64 years), with
recently diagnosed 1oSS constituted the study population. As a control group, 21
patients matched according to sex and age were randomly selected from patients at
one clinic in the Public Dental Service. Clinical examinations including
registrations of dental caries, restorations, and periodontal conditions were
performed. Unstimulated and stimulated salivary secretion rates were recorded.
The 1oSS group had a mean number of 16.4 +/- 8.9 and the control group 17.1 +/-
8.4 natural teeth. The 1oSS patients had significantly more DF crown surfaces (63
+/- 25.8 vs 43 +/- 21.3) and more inactive root caries (4.4 +/- 5.4 vs 0.5 +/-
0.9) than did the control patients. No significant differences were found between
the groups in the periodontal conditions. The mean value of the unstimulated
salivary secretion rate was 0.09 +/- 0.16 ml/15 min in the 1oSS group and 3.33 +/
2.81 ml/15 min in the control group. The stimulated secretion rate was 0.16 +/-
0.15 ml/min and 1.47 +/- 0.64 ml/min respectively. This study confirms results
from other studies that patients with 1oSS face a high risk of developing both
coronal and root caries due to xerostomia. The periodontal conditions are similar
to those found in patient groups in general dentistry.
PMID- 9768458
TI - Atopic dermatitis, conjunctivitis, and hand dermatitis among Swedish dental
personnel, including use of personal protective devices.
AB - A previous study on dental personnel in northern Sweden show that dentists had a
significantly higher prevalence of self-reported and physician-diagnosed atopic
dermatitis and conjunctivitis, compared to chair assistants and referents
(Lonnroth & Shahnavaz 1998). Further, significantly more male dentists reported
experience of hand dermatitis compared to male referents. To compare the
prevalence among dental personnel working in other geographical areas of Sweden,
and survey the use of personal protective equipment, a questionnaire study was
conducted during 1997, which included all dentists and his/her chair assistants,
working in general private and public dental care in Sweden. A total of 7384
dental personnel were included in the study, 4293 dentists (54.7% male and 45.3%
female), and 3090 chair assistants. Logistic regression was used for analysing
data. Results show that significantly more dentists reported symptoms of atopic
dermatitis, conjunctivitis, and hand dermatitis, and had been diagnosed by a
physician, compared to chair assistants. However, they did not report more sick
leave due to symptoms, compared to chair assistants. More female used protective
devices, than male, and more chair assistants than dentists. Significantly more
dental personnel in public dental care used protective devices, than in private
dental care. Use of gloves, and face mask, decreased with increasing age but, use
of eye protection, mainly in form of prescription spectacles, increased. The
prevalence of hand dermatitis decreased significantly with increasing age but,
more for female (p < 0.0001), than for male (p = 0.01).
PMID- 9768459
TI - Orthodontic aspects on feeding of young children. 1. A comparison between Swedish
and Norwegian-Sami children.
AB - 1-18 months old Norwegian-Sami girls from Karasjok/Katokeino were compared with
girls from Falkoping in Sweden. All Karasjok/Kautokeino children were breastfed,
usually until 1 year of age. Only a few developed a dummy- or fingersucking
habit. They started eating porridge at 4-5 months of age. At about half a year of
age they were fed dark, hard chewing bread to gnaw at. Cut and pulped adult food
was introduced during the end of the first year of life. In almost all cases the
children had dried reindeer meat to gnaw at. They were mostly fed by spoon and
drank from a cup. The Falkoping girls, on the other hand, were not so often
breastfed and for a shorter time. They usually became dummysuckers. The Falkoping
girls got almost all their nutrition during the first one or two years by sucking
or eating food with little chewing resistance. The differences in sucking and
chewing behavior could influence on the transversal development of the jaws.
PMID- 9768460
TI - A clinical evaluation of long term retention with bonded retainers made from
multi-strand wires.
AB - The majority of patients from 4 orthodontic clinics in the south west of Sweden
who have had bonded retainers on upper or lower anterior teeth for a period of at
least 5 years were examined. The total failure rate during 5 years of observation
was 36 per cent, slightly higher in the maxilla than in the mandible. The
retainer had become detached in 15 per cent of the teeth bonded. The failure rate
decreased during the 5 year period of observation. Seven fractures were reported,
all in the upper front teeth. The failure rate was reduced when the retainers
were positioned incisally, when larger diameter wires were used and in the 12
cases where a groove had been cut into the enamel to accept the retainer. The
findings suggest that a limited flexibility of the retainer may be an advantage.
In about 20 per cent of the retained segments minor rotations and small areas of
space opened between some of the teeth attached to the retainer. No new caries
lesions were found on any of the teeth associated with the bonded retainers
during the period of observation.
PMID- 9768461
TI - Introduction to impulsive aggression.
PMID- 9768462
TI - Defining, measuring, and predicting impulsive aggression: a heuristic model.
AB - Aggression research does not lack data--it lacks a model for integrating data.
One of the problems confronting aggression researchers is the extensive body of
multidisciplinary data that is difficult to synthesize to generate new directions
in research. This paper proposes one solution that starts by asking "what is the
minimal number of categories of concepts and measurements which are necessary to
describe a person?". The answer is four categories of concepts: biological;
cognitive; behavioral; environmental (physical and social). One way of many for
integrating these four categories of concepts is a proposed discipline neutral
heuristic model that is used herein to compare two different research approaches
to the study of impulsive aggression. This comparison identifies clearly the
differences in the two approaches with regard to different emphases among the
four categories of constructs for each program. Using the model an example of
common ground between the two approaches is sought as a basis for extending
aggression research. The main conclusion of one of the research programs was that
central nervous arousal is related to impulsive aggression. This program
demonstrated that phenytoin will reduce impulsive aggressive acts and has an
effect on CNS arousal. The other research program on impulsive aggression has
been at the forefront in demonstrating the well established inverse relationship
between serotonin levels and aggression. The comparison resulted in the
suggestion that both serotonin and phenytoin may relate to a common neurochemical
substrate which interacts in part to control CNS arousal, especially at the
cortical level. The proposed heuristic model made obvious the need to use
synthesizing concepts (e.g. information processing or language) which can
interrelate multidisciplinary concepts and data from different research programs
within the four categories of constructs when comparing interdisciplinary
research.
PMID- 9768463
TI - Neurobiologic correlates of violence: relevance to criminal responsibility.
AB - Studies addressing the relationship between neurotransmitter functioning and
violent crime are reviewed. A rich literature exists to support the notion that
monoamine (i.e., serotonin, dopamine, and norepinephrine) neurotransmitter
functioning is related to human aggressive behaviour. Results from these studies
provide, at best, indirect evidence that neurotransmitter abnormalities are
involved in violent criminal behavior. Few studies have specifically addressed
the role of neurotransmitter functioning in violent crime. To illustrate how
current knowledge in this area has been applied in forensic settings, a case
study in which neurotransmitter functioning was introduced as evidence to support
an insanity defense is presented. Potential problems associated with such
defenses are discussed.
PMID- 9768464
TI - Reduced prefrontal and increased subcortical brain functioning assessed using
positron emission tomography in predatory and affective murderers.
AB - There appear to be no brain imaging studies investigating which brain mechanisms
subserve affective, impulsive violence versus planned, predatory violence. It was
hypothesized that affectively violent offenders would have lower prefrontal
activity, higher subcortical activity, and reduced prefrontal/subcortical ratios
relative to controls, while predatory violent offenders would show relatively
normal brain functioning. Glucose metabolism was assessed using positron emission
tomography in 41 comparisons, 15 predatory murderers, and nine affective
murderers in left and right hemisphere prefrontal (medial and lateral) and
subcortical (amygdala, midbrain, hippocampus, and thalamus) regions. Affective
murderers relative to comparisons had lower left and right prefrontal
functioning, higher right hemisphere subcortical functioning, and lower right
hemisphere prefrontal/subcortical ratios. In contrast, predatory murderers had
prefrontal functioning that was more equivalent to comparisons, while also having
excessively high right subcortical activity. Results support the hypothesis that
emotional, unplanned impulsive murderers are less able to regulate and control
aggressive impulses generated from subcortical structures due to deficient
prefrontal regulation. It is hypothesized that excessive subcortical activity
predisposes to aggressive behaviour, but that while predatory murderers have
sufficiently good prefrontal functioning to regulate these aggressive impulses,
the affective murderers lack such prefrontal control over emotion regulation.
PMID- 9768465
TI - Antisocial personality disorder and psychopathy: diagnostic dilemmas in
classifying patterns of antisocial behavior in sentencing evaluations.
AB - Antisocial Personality Disorder (APD) and PCL-R psychopathy are critically
examined regarding their application to sentencing determinations. PCL-R
psychopathy is emerging in the literature as a more useful forensic diagnostic
construct than APD, which appears flawed by multiple weaknesses. These include
shifting diagnostic criteria, innumeracy problems, absence of symptom weighting,
temporal instability, and the equivalence of some symptoms with substance abuse
disorders. Additionally, APD overdiagnosis may result from inattention to issues
of social context, trauma history, and symptom pervasiveness. Neither objective
nor projective personality testing reliably differentiates APD. Finally, an APD
diagnosis does not always indicate criminal, much less incorrigible criminal
behavior. By contrast, PCL-R psychopathy results are strongly predictive of
criminal behavior and violent recidivism for Caucasian males through mid-life
residing in the community. Emerging research with the PCL-R regarding other
important populations and contexts is promising but generalization is currently
limited.
PMID- 9768466
TI - Impulsive corporal punishment by mothers and antisocial behavior and
impulsiveness of children.
AB - This study tested the hypothesis that corporal punishment (CP), such as spanking
or slapping a child for purposes of correcting misbehavior, is associated with
antisocial behavior (ASB) and impulsiveness by the child. The data were obtained
through interviews with a probability sample of 933 mothers of children age 2-14
in two small American cities. Analyses of variance found that the more CP
experienced by the child, the greater the tendency for the child to engage in ASB
and to act impulsively. These relationships hold even after controlling for
family socioeconomic status, the age and sex of the child, nurturance by the
mother, and the level of noncorporal interventions by the mother. There were also
significant interaction effects of CP with impulsiveness by the mother. When CP
was carried out impulsively, it was most strongly related to child impulsiveness
and ASB; when CP was done when the mother was under control, the relationship to
child behavior problems was reduced but still present. In view of the fact that
there is a high risk of losing control when engaged in CP, even by parents who
are not usually impulsive, and the fact that impulsive CP is so strongly
associated with child behavior problems, the results of this study suggest that
CP is an important risk factor for children developing a pattern of impulsive and
antisocial behavior which, in turn, may contribute to the level of violence and
other crime in society.
PMID- 9768467
TI - Legal and ethical duties of the clinician treating a patient who is liable to be
impulsively violent.
AB - This paper reviews published tort cases that arose after a patient impulsively
hurt or killed someone. Plaintiffs alleged breach of the duty to protect
(Tarasoff) or negligent release from hospital. There are sixteen cases involving
a variety of facts and diagnoses. As a matter of law courts typically hold that
impulsive violence is not foreseeable. One jury found a defendant negligent but
that verdict was ultimately overturned. Statutes on duty to protect do not imply
a duty to act on the fact patterns of impulsive violence in this sample. The
author concludes that the ethical duty to do careful clinical work is essentially
identical to the legal duty to use due care in these cases. The law imposes no
additional burden on the clinician in these cases.
PMID- 9768468
TI - Mapping cell wall polysaccharides of living microbial cells using atomic force
microscopy.
AB - Functionalized atomic force microscope tips were used to sense specific forces of
interaction between ligand-receptor pairs and to map the positions of
polysaccharides on a living microbial cell surface. Gold-coated tips were
functionalized with concanavalin A using a cross-linker with a spacer arm of 15.6
A. It was possible to measure the binding force between concanavalin A and mannan
polymers on the yeast (Saccharomyces cerevisiae) cell surface. This force ranged
from 75 to 200 pN. The shape of the force curve indicated that the polymers were
pulled away from the cell surface for a fairly long distance that sometimes
reached several hundred nanometres. The distribution of mannan on the cell
surface was mapped by carrying out the force measurement in the force volume mode
of atomic force microscopy (AFM). During the measurement, the maximum cantilever
deflection after contact between the tip and the sample was kept constant at 10
nm using trigger mode to keep the pressing force on the sample surface as gently
as possible at a force of 180 pN. This regime was used to minimize the non
specific adhesion between the tip and the cell surface. Specific molecular
recognition events took place on specific areas of the cell surface that could be
interpreted as reflecting a non-uniform distribution of mannan on the cell
surface.
PMID- 9768469
TI - Understanding intercellular interactions and cell adhesion: lessons from studies
on protein-metal interactions.
AB - To understand cell-cell interactions and the interactions of cells to non
biological materials, studies on binding forces between cellular proteins and
between proteins and non-biological material such as metal surfaces are
essential. The adsorption of proteins to solid-water interfaces is a
multifactorial and a multistep process. First steps are determined by long-range
interactions where surface properties such as hydrophobicity, distribution of
charged groups, ion concentrations and pH play important roles. In later steps
structural rearrangements in the protein molecule and dehydration effects become
more important making the adsorption process often irreversible. In the following
we demonstrate that protein A and tubulin have a specific type of interaction to
metal surfaces probably as an intermediate step in the adsorption process. The
proteins were attached to the tip of a microfabricated cantilever in such a way
that only one molecule interacts with the surface. By recording force-distance
curves with an atomic force microscope the adhesion forces of single molecules
binding to gold, titanium and indium-tinoxid surfaces were measured.
PMID- 9768470
TI - Tertiary structure of the hepatic cell protein fibrinogen in fluid revealed by
atomic force microscopy.
AB - Fibrinogen participates in important cellular physiological processes, such as
cell adhesion and blood clotting. Although the primary and secondary structures
of fibrinogen are known, its tertiary structure is yet to be determined. In
attempts to understand the tertiary structure of this important hydrated cellular
and plasma membrane protein, the present study using atomic force microscopy was
carried out. The techniques presented in this manuscript may also be applicable
to enhance the imaging of live cells as well as their subcellular components. The
authors have imaged fibrinogen by Tapping Mode atomic force microscopy in fluid.
Purified human fibrinogen, together with 15-nm colloidal gold particles serving
as an internal calibration standard, were adhered to a poly-L-lysine substrate on
freshly cleaved mica. Atomic force microscopy images were obtained using oxide
sharpened silicon nitride probes, either unaltered or with an electron beam
deposited extended tip. Although various structures were observed, the
predominant forms consisted of a bi- or trinodular slightly curved linear shape.
Approximately 300 of these structures were observed with six different tips (1
unaltered and 5 electron beam deposited) and their lengths and heights were
analyzed. The mean length of the fibrinogen molecules was 65.8 nm and the mean
height was 3.4 nm. The quantitative measurements were little influenced by the
shape of the tip, whereas the sharper electron beam deposited tips seemed to
produce qualitatively superior images.
PMID- 9768471
TI - An atomic force microscopic examination of the apical membrane of the mammalian
gastric gland.
AB - The authors have examined the morphology of the apical membrane of living gastric
glands from both the rat and rabbit with an atomic force microscope using both a
conventional upright configuration and in the new inverted bioscope mode.
Individual gastric glands were hand dissected and the apical membrane was exposed
using a microsurgical approach. The split open glands allowed to access and
directly image 4-6 cells with their apical axis available to the scanning tip of
the atomic force microscope. All cells were scanned in a physiological Ringer
solution at 37 degrees C. The scans revealed that we could visualize both
parietal and chief cells and to distinguish them via their unique apical
topography. The parietal cells showed a variety of small canaliculi that were
dispersed along the apical axis of the cell. Scans of chief cells revealed an
apical surface that was covered with microvilli along the entire apical margin.
The results of these studies show that it is indeed feasible to image living
gastric glands at 37 degrees C and to observe the surface topology of both the
parietal and chief cell.
PMID- 9768472
TI - The atomic force microscope detects ATP-sensitive protein clusters in the plasma
membrane of transformed MDCK cells.
AB - Plasma membrane proteins are supposed to form clusters that allow 'functional
cross-talk' between individual molecules within nanometre distance. However, such
hypothetical protein clusters have not yet been shown directly in native plasma
membranes. Therefore, we developed a technique to get access to the inner face of
the plasma membrane of cultured transformed kidney (MDCK) cells. The authors
applied atomic force microscopy (AFM) to visualize clusters of native proteins
protruding from the cytoplasmic membrane surface. We used the K+ channel blocker
iberiotoxin (IBTX), a positively charged toxin molecule, that binds with high
affinity to plasma membrane potassium channels and to atomically flat mica. Thus,
apical plasma membranes could be 'glued' with IBTX to the mica surface with the
cytosolic side of the membrane accessible to the scanning AFM tip. The topography
of these native inside-out membrane patches was imaged with AFM in electrolyte
solution mimicking the cytosol. The plasma membrane could be clearly identified
as a lipid bilayer with the characteristic height of 4.9 +/- 0.02 nm. Multiple
proteins protruded from the lipid bilayer into the cytosolic space with molecule
heights between 1 and 20 nm. Large protrusions were most likely protein clusters.
Addition of the proteolytic enzyme pronase to the bath solution led to the
disappearance of the proteins within minutes. The metabolic substrate ATP induced
a shape-change of the protein clusters and smaller subunits became visible. ADP
or the non-hydrolysable ATP analogue, ATP-gamma-S, could not exert similar
effects. It is concluded that plasma membrane proteins (and/or membrane
associated proteins) form 'functional clusters' in their native environment. The
'physiological' arrangement of the protein molecules within a cluster requires
ATP.
PMID- 9768473
TI - Using atomic force microscopy to investigate patch-clamped nuclear membrane.
AB - Nuclear patch clamp is an emerging research field that aims to disclose the
electrical phenomena underlying macromolecular transport across the nuclear
envelope (NE), its properties as an ion barrier and its function as an
intracellular calcium store. The authors combined the patch clamp technique with
atomic force microscopy (AFM) to investigate the structure-function relationship
of NE. In principle, patch clamp currents, recorded from the NE can indicate the
activity of the nuclear pore complexes (NPCs) and/or of ion channels in the two
biomembranes that compose the NE. However, the role of the NPCs is still nuclear
because the observed NE current in patch clamp experiments is lower than expected
from the known density of the NPCs. Therefore, AFM was applied to link patch
clamp currents to structure. The membrane patch was excised from the nuclear
envelope and, after electrical evaluation, transferred from the patch pipette to
a substrate. We could identify the native nuclear membrane patches with AFM at a
lateral and a vertical resolution of 3 nm and 0.1 nm, respectively. It was shown
that complete NE together with NPCs can be excised from the nucleus after their
functional identification in patch clamp experiments. However, we also show that
membranes of the endoplasmic reticulum can contaminate the tip of the patch
pipette during nuclear patch clamp experiments. This possibility must be
considered carefully in nuclear patch clamp experiments.
PMID- 9768474
TI - Rapid aldosterone-induced cell volume increase of endothelial cells measured by
the atomic force microscope.
AB - Atomic force microscopy (AFM) is a useful technique for imaging the surface of
living cells in three dimensions. The authors applied AFM to obtain morphological
information of individual cultured endothelial cells of bovine aorta under
stationary and strain conditions and to simultaneously measure changes in cell
volume in response to aldosterone. This mineralocorticoid hormone is known to
have acute, non-genomic effects on intracellular pH, intracellular electrolytes
and inositol-1,4,5-triphosphate production. In this study whether endothelial
cells under tension change their volume in response to aldosterone was tested.
Such changes were already shown in human leukocytes measured by Coulter counter.
In contrast to leukocytes that are more or less spherical and live in suspension,
endothelial cells exhibit a complex morphology and adhere to a substrate. Thus,
measurements of discrete cell volume changes in endothelial cells under
physiological condition is only feasible with more sophisticated techniques. By
using AFM we could precisely measure the absolute cell volume of individual
living endothelial cells. Before the addition of aldosterone the cell volume of
mechanically stressed endothelial cells mimicking arterial blood pressure was
1827 +/- 172 fl. Cell volume was found to increase by 28% 5 min after hormone
exposure. Twenty-five minutes later cell volume was back to normal despite the
continuous presence of aldosterone in the medium. Amiloride, a blocker of the
plasma membrane Na+/H+ exchanger prevented the initial aldosterone-induced volume
increase. Taken together, AFM disclosed a transient swelling of endothelial cells
induced by the activation of an aldosterone sensitive plasma membrane Na+/H+
exchanger.
PMID- 9768475
TI - A non-invasive method for the tight anchoring of cells for scanning force
microscopy.
AB - Use of scanning force microscopy (SFM) for high resolution imaging of cell
surfaces requires the cells to be tightly attached to substrates. Imaging of
loosely adhered RBL-2H3 cells enabled determination of the cell size and
investigation of larger structures and pseudopodia but failed in resolving more
detail. Immobilization under non-invasive conditions via flexible crosslinkers
containing a hydrophobic anchoring group enhanced resolution enormously. The
cells were tightly attached to the substrates and were not removed by shear
forces up to 80 nN as determined in a flow through apparatus. Morphological
structures and dynamic processes on cell surfaces were observed as well as
structural changes after cell stimulation upon ionomycin treatment. Molecular or
atomic resolution, however, was not attainable which is attributed to the
displacement of the flexible cell surface due to shear forces arising from the
scanning tip during contact mode.
PMID- 9768476
TI - Sleep schedules and daytime functioning in adolescents.
AB - Sleep and waking behaviors change significantly during the adolescent years. The
objective of this study was to describe the relation between adolescents'
sleep/wake habits, characteristics of students (age, sex, school), and daytime
functioning (mood, school performance, and behavior). A Sleep Habits Survey was
administered in homeroom classes to 3,120 high school students at 4 public high
schools from 3 Rhode Island school districts. Self-reported total sleep times
(school and weekend nights) decreased by 40-50 min across ages 13-19, ps < .001.
The sleep loss was due to increasingly later bedtimes, whereas rise times were
more consistent across ages. Students who described themselves as struggling or
failing school (C's, D's/F's) reported that on school nights they obtain about 25
min less sleep and go to bed an average of 40 min later than A and B students, ps
< .001. In addition, students with worse grades reported greater weekend delays
of sleep schedule than did those with better grades. Furthermore, this study
examined a priori defined adequate sleep habit groups versus less than adequate
sleep habit groups on their daytime functioning. Students in the short school
night total sleep group (< 6 hr 45 min) and/or large weekend bedtime delay group
(> 120 min) reported increased daytime sleepiness, depressive mood, and
sleep/wake behavior problems, ps < .05, versus those sleeping longer than 8 hr 15
min with less than 60 min weekend delay. Altogether, most of the adolescents
surveyed do not get enough sleep, and their sleep loss interferes with daytime
functioning.
PMID- 9768477
TI - Using writing instruments: invariances in young children and adults.
AB - In 2 studies, developmental changes in variability associated with handwriting
were investigated. In Study 1, variability in grip patterns and pen positioning
relative to a flat surface were examined in 3- and 5-year-olds and adults. The
results indicated that between 3 and 5 years of age there is a reduction in the
number of grips that individual children routinely use and a reduction in
variability associated with pen-surface positioning. In Study 2, the 3-year-old
children who participated in Study 1 were tested 6 months later. In comparison to
young 3-year-old children, older 3-year-olds use an adult grip pattern more often
and are less variable in pen-surface positioning, although the use of multiple
grip patterns is still common. The findings from both studies are considered in
relation to prior research that emphasized modal patterns of motor development
and newer work that uses developmental changes in variability to understand the
acquisition of motor skill.
PMID- 9768478
TI - Preliminary models of risk and protective factors for childhood homesickness:
review and empirical synthesis.
AB - Empirical research and conventional wisdom have suggested numerous risk and
protective factors for the development of homesickness. Yet no study has
integrated predictors and sequelae of homesickness into a testable statistical
model. As a first step in developing a pathogenic model of homesickness in
children, this study measured, factor analyzed, and modeled 14 predictors and 8
sequelae of homesickness. Using a sample of 293 boys, ages 8-16, spending 2 weeks
at an overnight summer camp, this study tested 2 alternate models, focusing on
the roles of boys' interpersonal attitudes, perceived control, and separation
expectations in the subsequent development of homesickness. Results indicated
that interpersonal attitudes and perceived control may predict boys'
preseparation beliefs about whether they will become homesick. This "homesick
disposition" combines with little prior separation experience to account for 69%
of the variance in self-reported homesickness. Homesickness was not a powerful
predictor of negative emotion, whereas interpersonal attitudes and perceived
control predicted 70% of the variance in negative emotion. Results are discussed
in the context of contemporary theories of homesickness.
PMID- 9768479
TI - Is there a "trochaic bias" in early word learning? Evidence from infant
production in English and French.
AB - Studies of speech perception and segmentation in the prelinguistic period, early
word production, and patterns of function word omission in early syntax have all
recently emphasized the role of the trochaic accentual pattern in English,
sometimes positing a universal trochaic bias. We make use of perceptual and
acoustic analyses of words and babble from 9 children acquiring English and 5
acquiring French in the late single-word period (13-20 months) to provide a
direct test for the existence of such a bias. Neither English nor French infant
vocalizations were exclusively trochaic. The iambic productions of American
infants were traced to the presence of iambic phrases in the input. Differences
between English and French in the acoustic realization of accent in infant
vocalizations were also traceable to adult patterns. However, the almost bipolar
distribution of trochaic and iambic patterns in the data from English-learning
infants was ultimately traceable to the integration of prosodic and segmental
patterning in individual child word production templates, themselves arguably the
product of an earlier acting articulatory filter.
PMID- 9768480
TI - The medium can obscure the message: young children's understanding of video.
AB - In the first few years of life, children acquire a great deal of general
information through symbolic media, including television. Here we explored
whether very young children would use information presented via video to solve a
retrieval problem. The children watched on a monitor as a toy was hidden in the
room next door. A group of 2 1/2-year-olds was very successful at finding the
hidden toy based on the televised hiding event, but a group of 2-year-olds was
not. Substantially better performance was achieved by other 2-year-olds who
either watched the hiding event directly through a window or who believed they
were watching directly (but were in fact looking at the monitor through the
window). These results (like those from other symbolic media such as models and
pictures) indicate that very young children have difficulty using a symbolic
representation as a source of information about an existing situation.
PMID- 9768481
TI - Intention and knowledge in preschoolers' conception of pretend.
AB - Experiments 1 and 2 investigated 3- and 4-year-olds' understanding of the
intended nature of pretend behaviors by testing their ability to distinguish
between involuntary behaviors and the same behaviors emitted intentionally
through acts of pretend. Four-year-olds' high rate of passing showed that (1)
they understood intention as a mental cause of action and (2) they construed
pretend behaviors mentalistically. Experiment 3 used the same contrastive
procedure to examine Lillard's contention that 4-year-olds do not understand the
knowledge conditions and hence the mental representational component of pretend
actions. Whereas nearly all of the 5-year-olds understood that an agent who did
not know of a specific animal could not be pretending to be that animal, 4-year
olds systematically associated ignorance with pretend. On the basis of the
combined findings of the present experiments, and other research showing a
mentalistic understanding of pretense by the age of 3 or 4, it was concluded that
the specific reasoning requirements of Lillard's tasks resulted in an
underestimation of children's appreciation of the mental features of pretend.
PMID- 9768482
TI - Wanting to be it: children's understanding of intentions underlying pretense.
AB - How children understand the mental state of pretense has recently become an
active area of inquiry, with some research suggesting that young children do not
understand that pretending is based on mentally representing some alternate state
of affairs. Because intention is thought to be understood earlier than mental
representation generally, these experiments tested whether children understand
pretense intentions at an earlier age than they understand pretense mental
representations. Children were told about a character's intentions and
conflicting actions, and were asked about the character's pretense. Across 5
experiments, children did not demonstrate appreciation that intention is crucial
to pretense. Various methodological factors that might have compromised the
results were examined, but to no effect.
PMID- 9768483
TI - Individual differences in contextual facilitation: evidence from dyslexia and
poor reading comprehension.
AB - Ninety-two 7- to 10-year-old children read words presented in isolation or
following a spoken sentence context. In absolute terms, poor readers showed more
contextual facilitation than good readers. However, when the relative benefit of
context was assessed, this was greater for children with better reading skills,
and comprehension was a better predictor of contextual facilitation than
decoding. Study 2 compared the performance of dyslexics with that of reading-age
matched poor comprehenders and normal readers. The dyslexics showed greater
contextual facilitation than the normal readers who, in turn, showed more priming
than poor comprehenders. The results show that dyslexic children use context to
compensate for poor decoding skills, whereas children with poor reading
comprehension skills fail to benefit from context as much as normal readers.
PMID- 9768484
TI - Environmental input and cognitive growth: a study using time-period comparisons.
AB - In this study, we examined the relation of input to cognitive growth in a single
population of children. We studied 4 domains: Language, Spatial Operations,
Concepts, and Associative Memory. Four groups of children drawn from the same
population were tested in October of kindergarten, April of kindergarten, October
of first grade, and April of first grade. These time points are 6 months apart,
but they span periods that differ in amount of school input children receive.
Much greater growth was found over time periods with greater amounts of school
input (October to April) than over time periods with less school input (April to
October) for Language, Spatial Operations, and Concepts, but not for Associative
Memory. These findings suggest that amount of input is causally related to
cognitive growth in particular domains.
PMID- 9768485
TI - Structure, stability, and development of young children's self-concepts: a
multicohort-multioccasion study.
AB - A new, individual administration procedure for assessing multiple dimensions of
self-concept for young children 5-8 years of age (Marsh, Craven, & Debus) was the
basis of this study. We expanded this application in a multicohort-multioccasion
(MCMO) study that provides simultaneous multicohort comparisons (cross-sectional
comparisons of different age cohorts) and longitudinal comparisons of the same
children on multiple occasions. There was reasonable support for predictions that
reliability, stability, factor structure, and the distinctiveness of the SDQ
factors would improve with age (a between-group age cohort comparison) and from 1
year to the next (a longitudinal comparison), and that small gender differences
were reasonably stable over age. Consistent with the proposal that children's
self-perceptions become more realistic with age, Time 1 (T1) teacher ratings were
more highly correlated with student self-ratings at T2 than T1 and contributed to
the prediction of T2 self-concept beyond effects mediated by T1 self-concepts.
The results support and expand the surprisingly good support for the
multidimensionality of self-concept responses for very young children using this
procedure.
PMID- 9768486
TI - Age trends in the use of social and temporal comparison for self-evaluation:
examination of a novel developmental hypothesis.
AB - Two studies tested the novel hypothesis that children use social comparison (SC)
for self-appraisal at an earlier age than they do temporal comparison (TC). The
effect of other's and of own prior outcome on performance and ability appraisal
and on self-evaluative strategies was examined using simple tasks and outcome
information. Results from 840 children at ages 4-8 confirmed that self-evaluative
SC was similar over age. Even 4- to 5-year-olds rated themselves higher after
doing better versus worse than another and explained their ratings in terms of
explicit SC. Social failure undermined continuing motivation at all ages. In
contrast, young children in TC conditions attended only to their last outcome,
and comparisons between current and prior outcomes increased with age. Self
evaluative biases were marked at age 5-6 and for boys in SC conditions. Results
clarify the role of cognitive and motivational factors in the development of SC
and TC.
PMID- 9768487
TI - Rejection sensitivity and children's interpersonal difficulties.
AB - Some children respond to social rejection in ways that undermine their
relationships, whereas others respond with more equanimity. This article reports
3 studies that test the proposition that rejection sensitivity--the disposition
to defensively (i.e., anxiously or angrily) expect, readily perceive, and
overreact to social rejection--helps explain individual differences in response
to social rejection. Data were from urban, minority (primarily Hispanic and
African American) fifth to seventh graders. Study 1 describes the development of
a measure of rejection sensitivity for children. Study 2 provides experimental
evidence that children who angrily expected rejection showed heightened distress
following an ambiguously intentioned rejection by a peer. Study 3 shows that
rejection sensitive children behaved more aggressively and experienced increased
interpersonal difficulties and declines in academic functioning over time.
PMID- 9768488
TI - A three year follow-up of attachment and indiscriminate friendliness in children
adopted from Romanian orphanages.
AB - Attachment and indiscriminately friendly behavior were assessed in children who
had spent at least 8 months in a Romanian orphanage (RO) and two comparison
groups of children: a Canadian-born, nonadopted, never institutionalized
comparison group (CB) and an early adopted comparison group adopted from Romania
before the age of 4 months (EA). Attachment was assessed using 2 measures: an
attachment security questionnaire based on parent report, and a Separation
Reunion procedure that was coded using the Preschool Assessment of Attachment.
Indiscriminately friendly behavior was examined using parents' responses to 5
questions about their children's behavior with new adults. Although RO children
did not score differently from either CB or EA children on the attachment
security measure based on parent report, they did display significantly more
insecure attachment patterns than did children in the other 2 groups. In
addition, RO children displayed significantly more indiscriminately friendly
behavior than both CB and EA children, who did not differ in terms of
indiscriminate friendliness. RO children's insecure attachment patterns were not
associated with any aspect of their institutional environment, but were related
to particular child and family characteristics. Specifically, insecure RO
children had more behavior problems, scored lower on the Stanford-Binet
Intelligence Scale, and had parents who reported significantly more parenting
stress than RO children classified as secure.
PMID- 9768489
TI - A prospective longitudinal study of attachment disorganization/disorientation.
AB - The research explores the antecedents and consequences of attachment
disorganization from a prospective longitudinal perspective. The relations of
attachment disorganization/disorientation to endogenous (e.g., maternal medical
history, infant temperament) and environmental (e.g., maternal caregiving
quality, infant history of abuse) antecedents and to behavioral consequences from
24 months to 19 years are examined. For the 157 participants in the longitudinal
study, attachment disorganization was correlated significantly with environmental
antecedents (e.g., maternal relationship and risk status, caregiving quality, and
infant history of maltreatment), but not with available endogenous antecedents.
Infant history of attachment disorganization was correlated with consequent
variables related to mother-child relationship quality at 24 and 42 months, child
behavior problems in preschool, elementary school and high school, and
psychopathology and dissociation in adolescence. Structural models suggest that
disorganization may mediate the relations between early experience and later
psychopathology and dissociation. The findings are considered within a
developmental view of psychopathology, that is, pathology defined in terms of
process, as a pattern of adaptation constructed by individuals in their
environments.
PMID- 9768490
TI - Growing or just getting along? Technical and adaptive competence in coping among
adolescents.
AB - This study examined coping among African American adolescents with learning
disabilities. Ninety-seven African American adolescents and their mother or
primary caregiver participated in the study. The study centered on a new
conceptual distinction between technical competence in coping and adaptive
competence in coping. Technical competence referred to short-term, reactive
attempts at coping based on individuals' abilities to find techniques for
reducing their feelings of distress. Adaptive competence referred to longer-term,
developmental processes of adaptive change that resulted in more global benefits
for the individual. Past literature was reassessed on the basis of this
conceptual distinction, and a new model of technical and adaptive competence in
coping was proposed based on developmental theory. Perceptions of coping efficacy
and the incidence of behavioral problems were regressed on measures of technical
and adaptive competence in coping. Results were explored first as a general test
of the model on the total sample, and second as a comparative analysis between
gender subsamples. Total sample findings were consistent with hypothesized
results. Technical competence was a better predictor of feelings of efficacy and
adaptive competence was a better predictor of behavioral problems. Gender
subsample differences were significant and supported a picture of gender-typed
approaches to coping.
PMID- 9768491
TI - Early child care and self-control, compliance, and problem behavior at twenty
four and thirty-six months. The NICHD Early Child Care Research Network.
AB - To evaluate child-care effects on young children's self-control, compliance, and
problem behavior, children enrolled in the NICHD Study of Early Child Care were
tested and observed in the laboratory and in child care at 24 and 36 months, and
mothers and caregivers completed questionnaires. Indicators of child-care
quantity, quality, stability, type, and age of entry, along with measures of
family background, mothering, and child characteristics obtained through the
first 3 years of life were used to predict 2 and 3 year child functioning.
Results revealed (1) mothering to be a stronger and more consistent predictor of
child outcomes than child care; (2) little evidence that early, extensive, and
continuous care was related to problematic child behavior, in contrast to results
from earlier work; (3) that among the child-care predictors, child-care quality
was the most consistent predictor of child functioning, although limited variance
could be explained by any (or all) child-care variables; and (4) that virtually
none of the anticipated interactions among child-care factors or between them and
family or child measures proved significant.
PMID- 9768492
TI - Peer relationships and self-esteem among children who have been maltreated.
AB - A prospective longitudinal design was employed to assess risks associated with
maltreatment in a representative community sample of 107 maltreated children and
an equal number of nonmaltreated comparison children. Heightened difficulties in
peer relationships and self-esteem were associated with greater severity and
chronicity of maltreatment. For example, children who experienced chronic
maltreatment were less well-liked by peers. Type of maltreatment was also related
to specific aspects of children's adjustment. For instance, sexual abuse
predicted low self-esteem, but not problems in peer relationships. Emotional
maltreatment, on the other hand, was related to difficulties in peer
relationships, but not to low self-esteem. Thus, the best predictions of specific
aspects of children's adjustment were provided by considering timing, type, and
severity of maltreatment. For some groups of maltreated children, having a good
friend was associated with improvement over time in self-esteem.
PMID- 9768494
TI - The development of display rule knowledge: linkages with family expressiveness
and social competence.
AB - The development of display rule knowledge and its associations with family
expressiveness (Study 1) and peer competence (Study 2) were investigated among
elementary school children. In Study 1, the display rule knowledge of 121
kindergartners and third graders was assessed using validated hypothetical
scenarios. There were significant grade differences in display rule knowledge
such that third graders compared to kindergartners more frequently combined
expression regulation with prosocial reasoning, norm-maintenance, and self
protective motives. Maternal reports of family emotional climates indicated that
aspects of negative expressiveness were related positively to self-protective
display rules and negatively to prosocial display rules. Study 2 included 93
third and fifth graders who reported on their display rule knowledge and on their
emotional reactions and strategies to resolve peer conflict. Classmates and
teachers provided ratings on social competence. Age differences for display rule
knowledge were not documented, but prosocial display rules were most consistently
related to hypothetical peer conflict responses and social competence. The
findings confirm that display rule knowledge is related in consistent and
systematic ways to what children learn within the family emotional context, how
they propose to resolve peer conflict, and how they are perceived by peers and
teachers.
PMID- 9768495
TI - Child development, molecular genetics, and what to do with genes once they are
found.
AB - Genes associated with behavioral dimensions and disorders are beginning to be
identified. Although it is difficult and expensive to find genes associated with
behavior, it is relatively easy and inexpensive to use genes that have already
been identified. We describe how genes are found, but the main goal of this
article is to outline what developmentalists can do with genes once they are
found and, hence, to encourage the use of DNA markers in developmental research.
We suggest that genes can be used to answer questions about developmental
continuities, about psychopathological patterns, and about environmental risk
mechanisms. Developmental questions include the causal mechanisms involved in
heterotypic continuity. Questions on psychopathological patterns address
heterogeneity (Do gene-behavior associations apply to disorders or to separate
components representing risk or protective factors?), comorbidity (Are gene
behavior associations diagnosis-specific?), and the links between normality and
disorder (Does a gene-behavior association for a disorder extend to related
dimensions of normal variation and vice versa?). Questions about environmental
risk mechanisms are informed by study of gene-environment interaction (Are
individuals who are at genetic risk more sensitive to specific psychosocial
risks?) and gene-environment correlation (Are individuals who are at genetic risk
more likely to be exposed to psychosocial risk?).
PMID- 9768496
TI - Low mitochondrial diversity and small effective population sizes of the copepods
Calanus finmarchicus and Nannocalanus minor: possible impact of climatic
variation during recent glaciation.
AB - Molecular population genetic diversity of two planktonic copepods of the North
Atlantic, Calanus finmarchicus and Nannocalanus minor (Crustacea, Copepoda,
Calanoida), was characterized using the sequence variation in a 350 bp region of
the mitochondrial 16S rRNA gene. The subarctic species, C. finmarchicus, shows
lower population genetic diversity (haplotype diversity, h = 0.368, SD = 0.043;
nucleotide diversity, pi = 0.00370, SD = 0.0026) than the temperate/subtropical
species, N. minor (h = 0.824, SD = 0.024; pi = 0.00502, SD = 0.0032). Effective
population sizes (N(e), estimated from numbers of haplotypes) and effective
female population sizes (Nf(e), estimated from nucleotide diversities) for the
two species are 10(7) to 10(10) smaller than census female population sizes (Nf)
estimated from observed densities and areal distributions. For both C.
finmarchicus and N. minor, Nf approximately 10(15), N(e) approximately 10(8), and
Nf(e) approximately 10(5). We hypothesize that the cause of both low levels of
molecular diversity and small effective population sizes of the two species is
the impact of glaciation during the past 20,000 years. C. finmarchicus may have
experienced 75% range reduction and latitudinal displacement during the last
glacial maximum at 18,000 years BP, giving rise to a genetic bottleneck; this may
explain low diversity and an L-shaped distribution of pairwise haplotype
differences. In contrast, N. minor may have experienced range reduction of only
30% and less change in latitudinal extent, with less impact of levels of
molecular diversity and the shape of the pairwise difference distribution.
Although marine zooplankton species are highly abundant, conservation biologists
should note that their numbers may vary significantly on climatic to evolutionary
time scales, generating low levels of molecular genetic diversity.
PMID- 9768497
TI - Species identification using genetic tools: the value of nuclear and
mitochondrial gene sequences in whale conservation.
AB - DNA sequence analysis is a powerful tool for identifying the source of samples
thought to be derived from threatened or endangered species. Analysis of
mitochondrial DNA (mtDNA) from retail whale meat markets has shown consistently
that the expected baleen whale in these markets, the minke whale, makes up only
about half the products analyzed. The other products are either unregulated small
toothed whales like dolphins or are protected baleen whales such as humpback,
Bryde's, fin, or blue whales. Independent verification of such mtDNA
identifications requires analysis of nuclear genetic loci, but this is
technically more difficult than standard mtDNA sequencing. In addition, evolution
of species-specific sequences (i.e., fixation of sequence differences to produce
reciprocally monophyletic gene trees) is slower in nuclear than in mitochondrial
genes primarily because genetic drift is slower at nuclear loci. When will use of
nuclear sequences allow forensic DNA identification? Comparison of neutral
theories of coalescence of mitochondrial and nuclear loci suggests a simple rule
of thumb. The "three-times rule" suggests that phylogenetic sorting at nuclear
loci is likely to produce species-specific sequences when mitochondrial alleles
are reciprocally monophyletic and the branches leading to the mtDNA sequences of
a species are three times longer than the average difference observed within
species. A preliminary test of the three-times rule, which depends on many
assumptions about the species and genes involved, suggests that blue and fin
whales should have species-specific sequences at most neutral nuclear loci,
whereas humpback and fin whales should show species-specific sequences at fewer
nuclear loci. Partial sequences of actin introns from these species confirm the
predictions of the three-times rule and show that blue and fin whales are
reciprocally monophyletic at this locus. These intron sequences are thus good
tools for the identification of these species and will afford a chance to
identify putative hybrid blue/fin whales thought to have entered the retail
market after 1989.
PMID- 9768498
TI - Analysis of di-n-butylphthalate biotransformation in cattle by liquid
chromatography/ion trap mass spectrometry/mass spectrometry.
AB - The nature of products of contamination intake were investigated in cattle dosed
with [14C]di-n-butylphthalate (DBP). Radio-labelled metabolites were extracted
from bile, faeces, plasma and urine onto solid-phase media, fractionated by ion
exchange chromatography, separated by reverse phase HPLC and analysed by negative
ion atmospheric pressure chemical ionization mass spectrometry(n) (LCQ,
Finnigan). All matrices contained a common major metabolite [deprotonated
molecular ion (M-H)- m/z 221] which coeluted with and had an identical daughter
ion spectrum to reference monobutylphthalate (MBP). MBP was metabolised to a beta
glucuronidase sensitive compound (M-H)- m/z 397 whose spectrum contained daughter
ions (m/z 175 and 221) consistent with the parent glucuronide. A further three
beta-glucuronidase resistant radio-labelled metabolites were also produced (M-H-
m/z 165, 193 and 237); comparison of daughter ion spectra with those of reference
MBP and phthalic acid indicated identity with phthalic acid, monoethylphthalate
(MEP) and monohydroxybutylphthalate (MHBP) respectively. The presence of a
benzoate daughter ion (m/z 121) in all spectra was indicative of side chain
biotransformation. Both MBP and MEP contained a phthalate daughter ion (m/z 165)
indicating loss of a butyl and ethyl side chain respectively. A daughter ion of
m/z 89 derived from the side chain provided evidence that the third metabolite
was MHBP. Incubation of DBP with isolated bovine hepatocytes produced the same
metabolites and provided relatively clean samples for LC/MSn analysis. Detection
of these DBP metabolites in meat or dairy food products will provide evidence for
environmental exposure and biotransformation in vivo, whereas the presence of the
parent compound would suggest contamination during food processing and packaging.
PMID- 9768499
TI - Characterization of enzymatic pectin digests by matrix-assisted laser
desorption/ionization mass spectrometry.
AB - The use of matrix-assisted laser desorption/ionization time-of-flight mass
spectrometry for the characterization of partially methyl-esterified enzymatic
pectin digests is described. The sensitivities of several matrices, positive and
negative ion modes and desalting techniques for these acidic oligosaccharides
were compared. The most favorable results were obtained with a thin-layer
preparation of a mixture of 2,4,6-trihydroxyacetophenone and nitrocellulose in
the negative ion mode. Results are presented demonstrating the sensitive
characterization of separated and unseparated high-ester pectin digests obtained
after complete digestion using Aspergillus niger pectin lyase and the analysis of
digests after chemical modification. In the case of unseparated digests, the
analysis of methylation patterns is demonstrated. Oligomers with a degree of
polymerization up to 40 were detected after enrichment of large oligomers by
propan-2-ol precipitation.
PMID- 9768500
TI - Precolumn derivatization and capillary liquid chromatographic/frit-fast atom
bombardment mass spectrometric analysis of cytokinins in Arabidopsis thaliana.
AB - New cytokinin derivatives with high surface activity were developed for capillary
liquid chromatography/frit-fast atom bombardment (FAB) mass spectrometry.
Propionyl ester derivatives of cytokinin nucleosides and glucosides and
benzylamine derivatives of cytokinin bases gave stronger [M + H]+ ion currents
than the underivatized compounds. In trace analysis by selective reaction
monitoring, low (fmole) detection limits were found. In qualitative analysis by
B/E-linked scanning, the derivatives also gave more spectral information, owing
to the presence of fragment ions, diagnostic for the sugar moieties of
nucleosides and glucosides, not present in the spectra of underivatized
compounds. THe proposed FAB method was used to identify and quantify 10
isoprenoid cytokinins in Arabidopsis thaliana, including free bases, nucleosides,
nucleotides and glucosides.
PMID- 9768501
TI - Pelvic limb musculature in the emu Dromaius novaehollandiae (Aves:
Struthioniformes: Dromaiidae): adaptations to high-speed running.
AB - Emus provide an excellent opportunity for studying sustained high-speed running
by a bird. Their pelvic limb musculature is described in detail and morphological
features characteristic of a cursorial lifestyle are identified. Several
anatomical features of the pelvic limb reflect the emus' ability for sustained
running at high speeds: (1) emus have a reduced number of toes and associated
muscles, (2) emus are unique among birds in having a M. gastrocnemius, the most
powerful muscle in the shank, that has four muscle bellies, not the usual three,
and (3) contribution to total body mass of the pelvic limb muscles of emus is
similar to that of the flight muscles of flying birds, whereas the pelvic limb
muscles of flying birds constitute a much smaller proportion of total body mass.
Generally, the pelvic limb musculature of emus resembles that of other ratites
with the notable exception of M. gastrocnemius. The presence and arrangement of
four muscle bellies may increase the effectiveness of M. gastrocnemius and other
muscles during cursorial locomotion by moving the limb in a cranio-caudal rather
than a latero-medial plane.
PMID- 9768502
TI - Contribution of the vertebral artery to cerebral circulation in the rat snake
Elaphe obsoleta.
AB - Blood supplying the brain in vertebrates is carried primarily by the carotid
vasculature. In most mammals, cerebral blood flow is supplemented by the
vertebral arteries, which anastomose with the carotids at the base of the brain.
In other tetrapods, cerebral blood is generally believed to be supplied
exclusively by the carotid vasculature, and the vertebral arteries are usually
described as disappearing into the dorsal musculature between the heart and head.
There have been several reports of a vertebral artery connection with the
cephalic vasculature in snakes. We measured regional blood flows using
fluorescently labeled microspheres and demonstrated that the vertebral artery
contributes a small but significant fraction of cerebral blood flow
(approximately 13% of total) in the rat snake Elaphe obsoleta. Vascular casts of
the anterior vessels revealed that the vertebral artery connection is indirect,
through multiple anastomoses with the inferior spinal artery, which connects with
the carotid vasculature near the base of the skull. Using digital subtraction
angiography, fluoroscopy, and direct observations of flow in isolated vessels, we
confirmed that blood in the inferior spinal artery flows craniad from a point
anterior to the vertebral artery connections. Such collateral blood supply could
potentially contribute to the maintenance of cerebral circulation during
circumstances when craniad blood flow is compromised, e.g., during the
gravitational stress of climbing.
PMID- 9768503
TI - Compressive loading on bone surfaces from muscular contraction: an in vivo study
in the miniature pig, Sus scrofa.
AB - Several authors have speculated that muscles contracting adjacent to bony
surfaces may cause compressive loads against the bone and thus influence skull
development. This study was undertaken to evaluate the premise of this argument.
A flat, semiconductor pressure transducer was surgically placed on bony surfaces
beneath muscle attachments. Pressures were recorded during normal mastication (n
= 7) and while overlying muscles were stimulated in anesthetized pigs (n = 15).
The transducer was highly specific; no pressure was recorded in quiescent or
passively stretched muscles or when other muscles were stimulated. Contraction of
the overlying muscles exerted high normal loads on the bone, always exceeding
systolic blood pressure (16 kPa). Temporal fossa pressure during mastication
followed temporalis electromyographic (EMG) signals with a lag period
approximating the twitch contraction time. When three different sites were
compared in anesthetized animals, compressive load was highest on the temporal
fossa (111.4 +/- 56.5 kPa, n = 15), intermediate on the mandibular angle (58.4 +/
28.3 kPa, n = 4), and lowest on the medial side of the zygomatic arch (37.2 +/-
19.7 kPa, n = 15). Pressure amplitudes were not related to body size or relative
muscle size. Muscle complexity and compartmental constraints did appear to
influence pressure. Disruption of the external aponeurosis of the masseter
decreased pressure on the mandibular angle by 45%, confirming the importance of
tendinous constraint in determining pressure production. Thus, contracting
muscles exert substantial but site-specific compressive loads on adjacent bone
surfaces.
PMID- 9768504
TI - Effects of step size and break-point criterion on progressive-ratio performance.
AB - Key pecking by pigeons was maintained by arithmetic progressive-ratio schedules
of food delivery. Successive conditions arranged different step sizes, and each
condition remained in effect until behavior appeared stable. Each session
continued until a period of time passed in which no key pecks were recorded (the
break-point criterion); both a 5-min and a 15-min criterion were tested across a
range of step sizes. Average breaking points (i.e, the largest ratio completed)
were relatively unaffected by step-size magnitude, whereas the average number of
ratios completed and average response rates generally declined across increasing
step sizes. Within sessions, preratio pauses were relatively short and fairly
constant in duration as the ratio increased; pause durations increased rapidly
near the end of a session. The relation between the average number of completed
ratios and step size was described well by a power function [y = b(xa), in which
y represents the average number of completed ratios, x represents the step size,
and a and b are fitted parameters]. Increasing the break-point criterion from 5
to 15 min resulted in increased values of b, whereas parameter a was relatively
unaffected and was close to -1 (consistent with the lack of effect of step size
on breaking point). This function also provided an excellent description of data
drawn from previous reports.
PMID- 9768505
TI - Effects of variable-interval value and amount of training on stimulus
generalization.
AB - In Experiment 1 pigeons pecked a key that was illuminated with a 501-nm light and
obtained food by doing so according to a variable-interval (VI) schedule of
reinforcement, the mean value of which differed across groups: either 30 s, 120
s, or 240 s. The pigeons in all three groups were trained for 10 50-min sessions.
Generalization testing was conducted in extinction with different wavelengths of
light. Absolute and relative generalization gradients were similar in shape for
the three groups. Experiment 2 was a systematic replication of Experiment 1 using
line orientation as the stimulus dimension and a mean VI value of either 30 s or
240 s. Again, gradients of generalization were similar for the two groups. In
Experiment 3 pigeons pecked a key that was illuminated with a 501-nm light and
obtained food reinforcers according to either a VI 30-s or a 240-s schedule.
Training continued until response rates stabilized (> 30 sessions). For subjects
trained with the 30-s schedule, generalization gradients were virtually identical
regardless of whether training was for 10 sessions (Experiment 1) or until
response rates stabilized. For subjects trained with the VI 240-s schedule,
absolute generalization gradients for subjects trained to stability were
displaced upward relative to gradients for subjects trained for only 10 sessions
(Experiment 1), and relative generalization gradients were slightly flatter.
These results indicate that the shape of a generalization gradient does not
necessarily depend on the rate of reinforcement during 10-session single-stimulus
training but that the effects of prolonged training on stimulus generalization
may be schedule dependent.
PMID- 9768506
TI - Ratio size and cocaine concentration effects on oral cocaine-reinforced behavior.
AB - Monkeys were given a choice between cocaine solutions and water under concurrent
fixed-ratio reinforcement schedules. The operant response was spout contact. Six
rhesus monkeys served as subjects. The cocaine concentration was varied from
0.0125 to 0.8 mg/ml, and the fixed-ratio value was varied from 8 to 128. Cocaine
maintained higher response rates than did water over a wide range of conditions.
Response rate and number of cocaine deliveries per session were inverted U-shaped
functions of concentration. These functions were shifted to the right as the
fixed ratio was increased. The number of cocaine deliveries was more persistent
as fixed-ratio value was increased when the unit dose was larger rather than
smaller. Cocaine consumption was analyzed as a function of unit price (fixed
ratio value divided by cocaine concentration), and unit price accounted for
between 77% and 92% of the variance in cocaine consumption for individual
monkeys. The current data support the claim that a drug's reinforcing effects
increase directly with dose and underscore the need to gather parametric data
when examining the effects of experimental manipulations on a drug-reinforced
baseline.
PMID- 9768507
TI - Mental rotation and temporal contingencies.
AB - A task that requires subjects to determine whether two forms of the same shape,
but in different orientations, are mirror images or identical except for
orientation is called a handedness recognition task. Subjects' reaction times
(RT) on this task are consistently related to the angular disparity (termed
alpha) between the two presented forms. This pattern of data has been interpreted
to indicate that subjects solve the task by imagining that one of the forms
rotates into the orientation of the other (termed mental rotation). The speed
with which one imagines one of the forms rotating has been widely considered a
fixed capability of the individual, and thus immune to the effect of
contingencies. We present an experiment that assesses the effects of temporal
contingencies in a handedness recognition task on the slope of the function RT =
f(alpha). The data indicate that the slope of this function can come under the
control of temporal contingencies.
PMID- 9768508
TI - Superresolution and convergence properties of the expectation-maximization
algorithm for maximum-likelihood deconvolution of incoherent images.
AB - Computational optical-sectioning microscopy with a nonconfocal microscope is
fundamentally limited because the optical transfer function, the Fourier
transform of the point-spread function, is exactly zero over a conic region of
the spatial-frequency domain. Because of this missing cone of optical
information, images are potentially artifactual. To overcome this limitation,
superresolution, in the sense of band extrapolation, is necessary. I present a
frequency-domain analysis of the expectation-maximization algorithm for maximum
likelihood image estimation that shows how the algorithm achieves this band
extrapolation. This analysis gives the theoretical absolute bandwidth of the
restored image; however, this absolute value may not be realistic in many cases.
Then a second analysis is presented that assumes a Gaussian point-spread function
and a specimen function and shows more realistic behavior of the algorithm and
demonstrates some of its properties. Experimental results on the superresolving
capability of the algorithm are also presented.
PMID- 9768509
TI - Total least-squares reconstruction with wavelets for optical tomography.
AB - In a previous paper [Zhu et al., J. Opt. Soc. Am. A 14, 799 (1997)] an iterative
algorithm for obtaining the total least-squares (TLS) solution of a linear system
based on the Rayleigh quotient formulation was presented. Here we derive what to
our knowledge are the first statistical properties of this solution. It is shown
that the Rayleigh-quotient-form TLS (RQF-TLS) estimator is equivalent to the
maximum-likelihood estimator when noise terms in both data and operator elements
are independent and identically distributed Gaussian. A perturbation analysis of
the RQF-TLS solution is derived, and from it the mean square error of the RQF-TLS
solution is obtained in closed form, which is valid at small noise levels. We
then present a wavelet-based multiresolution scheme for obtaining the TLS
solution. This method was employed with a multigrid algorithm to solve the linear
perturbation equation encountered in optical tomography. Results from numerical
simulations show that this method requires substantially less computation than
the previously reported one-grid TLS algorithm. The method also allows one to
identify regions of interest quickly from a coarse-level reconstruction and
restrict the reconstruction in the following fine resolutions to those regions.
Finally, the method is less sensitive to noise than the one-grid TLS and
multigrid least-squares algorithms.
PMID- 9768510
TI - Scattering of electromagnetic waves from dense distributions of spheroidal
particles based on Monte Carlo simulations.
AB - In a dense discrete random medium, the propagation and scattering of waves are
affected not only by the individual properties of the particles such as size,
shape, and permittivity, but also by group properties such as the statistics of
relative particle positions and relative orientations. We use Monte Carlo
simulations to investigate the interactions of electromagnetic waves with a dense
medium consisting of spheroidal particles for cases of random orientation and for
cases of aligned orientation. A shuffling process is used to generate the
positions of densely packed spheroids. Multiple-scattering equations are
formulated by means of the volume integral equation and are solved numerically.
The scattering results are averaged over realizations. Numerical results are
presented for the extinction rates and the phase matrices. Salient features of
the numerical results indicate that (1) the extinction rates of densely packed
small spheroids are smaller than those of independent scattering; (2) for aligned
spheroids, the extinction rates are polarization dependent; and (3) the co
polarized part of the phase matrix for densely packed spheroids is smaller than
that of independent scatering, while the cross-polarized part is larger than that
for independent scattering. This means that the ratio of cross-polarization to co
polarization is significantly higher than that of independent scattering.
PMID- 9768511
TI - Fourier transform ion cyclotron resonance mass spectrometry: a primer.
AB - This review offers an introduction to the principles and generic applications of
FT-ICR mass spectrometry, directed to readers with no prior experience with the
technique. We are able to explain the fundamental FT-ICR phenomena from a
simplified theoretical treatment of ion behavior in idealized magnetic and
electric fields. The effects of trapping voltage, trap size and shape, and other
nonidealities are manifested mainly as perturbations that preserve the idealized
ion behavior modified by appropriate numerical correction factors. Topics
include: effect of ion mass, charge, magnetic field, and trapping voltage on ion
cyclotron frequency; excitation and detection of ICR signals; mass calibration;
mass resolving power and mass accuracy; upper mass limit(s); dynamic range;
detection limit, strategies for mass and energy selection for MSn; ion
axialization, cooling, and remeasurement; and means for guiding externally formed
ions into the ion trap. The relation of FT-ICR MS to other types of Fourier
transform spectroscopy and to the Paul (quadrupole) ion trap is described. The
article concludes with selected applications, an appendix listing accurate
fundamental constants needed for ultrahigh-precision analysis, and an annotated
list of selected reviews and primary source publications that describe in further
detail various FT-ICR MS techniques and applications.
PMID- 9768512
TI - A secretory cellulose-binding protein cDNA cloned from the root-knot nematode
(Meloidogyne incognita).
AB - A cDNA encoding a secretory cellulose-binding protein was cloned from the root
knot nematode (Meloidogyne incognita) with RNA fingerprinting. The putative full
length cDNA, named Mi-cpb-1, encoded a 203 amino acid protein containing an N
terminal secretion signal peptide. The C-terminal sequence of the putative MI-CBP
1 was similar to a bacterial-type cellulose-binding domain, whereas the N
terminal sequence did not show significant similarity to any proteins in data
bases. Recombinant MI-CBP-1 lacked cellulase activity, but bound to cellulose and
plant cell walls. In Southern blot hybridization, Mi-cbp-1 hybridized with
genomic DNA from M. incognita, M. arenaria, and M. javanica, but not M. hapla,
Heterodera glycines, or Caenorhabditis elegans. Polyclonal antibodies raised
against recombinant MI-CBP-1 strongly labeled secretory granules in subventral
gland cells of second-stage juveniles in indirect immunofluorescence microscopy.
Enzyme-linked immunosorbent assay detection of MI-CBP-1 in stylet secretions of
second-stage juveniles with the polyclonal antibodies indicated MI-CBP-1 could be
secreted through the nematodes' stylet, suggesting that the cellulose-binding
protein may have a role in pathogenesis.
PMID- 9768513
TI - nec1, a gene conferring a necrogenic phenotype, is conserved in plant-pathogenic
Streptomyces spp. and linked to a transposase pseudogene.
AB - We are investigating the genetic basis for, and evolution of, plant pathogenicity
in Streptomyces spp. The plant-pathogenic species S. scabies, S. acidiscabies,
and S. turgidiscabies cause the scab disease of potato and produce the
phytotoxins, thaxtomins. Forty-three Streptomyces strains representing the three
species were evaluated; all thaxtomin A-producing Streptomyces strains were
pathogenic on potato tubers and all but one hybridized to nec1 and ORFtnp, two
genes previously cloned from S. scabies ATCC 41973. nec1 confers a pathogenic
phenotype on S. lividans TK24, a nonpathogen, and ORFtnp is a transposase
pseudogene located 5' to nec1. The eight nonpathogenic strains tested neither
produced thaxtomin A nor hybridized to nec1. ORFtnp and nec1 occurred on a single
PvuII restriction fragment in all thaxtomin A-producing Streptomyces strains. The
nucleotide sequences of the homologs of nec1 and ORFtnp from two pathogenic
strains each of S. scabies, S. acidiscabies, and S. turgidiscabies were
identical; oligonucleotide primers specific to this gene amplified homologs from
all strains that hybridized to nec1. We propose that nec1 and ORFtnp have been
horizontally mobilized from S. scabies to S. acidiscabies and S. turgidiscabies,
and that nec1 is involved in pathogenicity and physically linked to the thaxtomin
A biosynthetic genes.
PMID- 9768514
TI - The isolation and mapping of disease resistance gene analogs in maize.
AB - Many of the plant disease resistance genes that have been isolated encode
proteins with a putative nucleotide binding site and leucine-rich repeats (NBS
LRR resistance genes). Oligonucleotide primers based on conserved motifs in and
around the NBS of known NBS-LRR resistance proteins were used to amplify
sequences from maize genomic DNA by polymerase chain reaction (PCR). Eleven
classes of non-cross-hybridizing sequences were obtained that had predicted
products with high levels of amino acid identity to NBS-LRR resistance proteins.
These maize resistance gene analogs (RGAs) and one RGA clone obtained previously
from wheat were used as probes to map 20 restriction fragment length polymorphism
(RFLP) loci in maize. Some RFLPs were shown to map to genomic regions containing
virus and fungus resistance genes. Perfect cosegregation was observed between RGA
loci and the rust resistance loci rp1 and rp3. The RGA probe associated with rp1
also detected deletion events in several rp1 mutants. These data strongly suggest
that some of the RGA clones may hybridize to resistance genes.
PMID- 9768515
TI - Sulfation of nod factors via nodHPQ is nodD independent in Rhizobium tropici
CIAT899.
AB - A cosmid from the Rhizobium tropici CIAT899 symbiotic plasmid, containing most of
the nodulation genes described in this strain, has been isolated. Although this
cosmid does not carry a nodD gene, it confers ability to heterologous Rhizobium
spp. to nodulate R. tropici hosts (Phaseolus vulgaris, Macroptilium
atropurpureum, and Leucaena leucocephala). The observed phenotype is due to
constitutive expression of the nodABCSUIJ operon, which has lost its regulatory
region and is expressed from a promoter present in the cloning vector. Thin-layer
chromatography (TLC) analysis of the Nod factors produced by this construction
shows that it is still capable of synthesizing sulfated compounds, suggesting
that the nodHPQ genes are organized as an operon that is transcribed in a nodD
independent manner and is not regulated by flavonoids.
PMID- 9768518
TI - The endopolygalacturonase gene Bcpg1 is required for full virulence of Botrytis
cinerea.
AB - Botrytis cinerea, a fungus that causes diseases in over 200 plant species,
secretes a number of endopolygalacturonases that have been suggested to be
involved in pathogenesis. However, so far the corresponding genes have not been
isolated from this fungus. We cloned Bcpg1, encoding endopolygalacturonase, with
the pgaII gene from Aspergillus niger as a heterologous probe. The Bcpg1 gene is
expressed to similar levels in liquid cultures of B. cinerea containing either 1%
polygalacturonic acid or 1% sucrose, and is expressed during infection of tomato
leaves. The Bcpg1 gene was eliminated by partial gene replacement, and the
resulting mutants were tested for virulence on tomato leaves and fruits, as well
as on apple fruits. Although the mutants were still pathogenic and displayed
similar primary infections when compared with control strains, a significant
decrease in secondary infection, i.e., growth of the lesion beyond the
inoculation spot, was observed on all three host tissues. These results indicate
that the Bcpg1 gene is required for full virulence.
PMID- 9768520
TI - Starving tumors of their lifeblood.
PMID- 9768521
TI - Bloodless testing.
PMID- 9768522
TI - Designer estrogens.
PMID- 9768523
TI - Review article: the use of biotherapeutic agents in the prevention and treatment
of gastrointestinal disease.
AB - There is presently a lack of well conducted clinical trials demonstrating any
significant benefits of probiotics in humans. With the exception of diarrhoea due
to rotavirus infection in children there is little evidence from randomized,
double-blind, placebo-controlled studies that bacterial probiotics have a
significant beneficial action in preventing diarrhoea of any cause. The yeast
Saccharomyces boulardii has been shown to be of benefit in the prevention of
antibiotic-associated diarrhoea but not in preventing infection with Clostridium
difficile. S. boulardii may also be of benefit in preventing relapse of C.
difficile infection. Because of the simplicity of in vitro systems and some
animal models, beneficial characteristics of probiotics such as the ability of
bacteria to bind to epithelial surfaces are not always transferable to humans.
Thus any postulated benefit from consumption of probiotic bacteria should only be
accepted as fact after testing in clinical studies. This review outlines our
present knowledge of the mode of action of probiotics and presents the data from
clinical trials on their use.
PMID- 9768524
TI - Review article: one-week clarithromycin triple therapy regimens for eradication
of Helicobacter pylori.
AB - BACKGROUND: One-week triple therapies have been endorsed as the treatment
regimens of choice for eradication of Helicobacter pylori infection. Those that
include clarithromycin appear to be the most effective. AIM: To review reports of
triple therapies that include clarithromycin. METHODS: Reports were identified
from the literature to May 1998. The variation between study designs prevents a
formal meta-analysis. A measure of the relative efficacies of regimens has,
however, been gained by comparison and by pooling of intention-to-treat
eradication rates. RESULTS: One hundred and ninety-two studies were identified
which included 264 treatment arms of a 1-week triple therapy composed of
clarithromycin with amoxycillin or a nitroimidazole (metronidazole or
tinidazole), and either ranitidine bismuth citrate or a proton pump inhibitor
(omeprazole, lansoprazole or pantoprazole). From reports of these studies, an
intention-to-treat H. pylori eradication rate could be determined from 210
treatment arms of 151 studies. CONCLUSIONS: There is little to choose between the
efficacies of 1-week clarithromycin-based triple therapy eradication regimens.
However, those comprising clarithromycin, a nitroimidazole and either ranitidine
bismuth citrate or a high dose of omeprazole are, in general, the most effective.
Against antibiotic-resistant strains of H. pylori, regimens including ranitidine
bismuth citrate may be more effective than those including a proton pump
inhibitor.
PMID- 9768525
TI - Idiopathic bile acid malabsorption: qualitative and quantitative clinical
features and response to cholestyramine.
AB - BACKGROUND: Idiopathic bile acid malabsorption is a poorly recognized cause of
chronic diarrhoea. The SeHCAT (75Selenium HomotauroCholic Acid Test) can
accurately diagnose this condition. AIM: To identify patients with idiopathic
bile acid malabsorption, to describe their clinical features, both qualitatively
and quantitatively, and to assess the response to cholestyramine. METHOD:
Idiopathic bile acid malabsorption was considered in all patients complaining of
chronic diarrhoea. They were included in the study if their SeHCATs were positive
(< 15% retention) and secondary causes of bile acid malabsorption were excluded.
The response to therapy with cholestyramine was assessed. RESULTS: Nine patients
were diagnosed with idiopathic bile acid malabsorption (median SeHCAT retention
8%, range 3-12.6). Their median daily faecal weight was 285 g (range 85-676) and
median faecal fat output was 17 mmol/24 h (range 8.3-38.8). Six patients had an
immediate response to cholestyramine. There was a marked reduction in stool
frequency (median stool frequency pre-treatment 5/day vs. 2/day post-treatment, P
= 0.03). Five patients had large volume diarrhoea (faecal weight > 200 g/day) and
three had steatorrhoea. CONCLUSIONS: Idiopathic bile acid malabsorption, once
suspected, especially by documenting true 'large volume' watery diarrhoea or
steatorrhoea, is easily diagnosed and response to therapy is often very good.
There is often a previous history of gastrointestinal infection and this
condition should be considered in patients with chronic diarrhoea of undetermined
origin, especially before they are labelled as having irritable bowel syndrome.
PMID- 9768526
TI - Ferric trimaltol corrects iron deficiency anaemia in patients intolerant of iron.
AB - BACKGROUND: Oral iron supplements, which are usually in the form of ferrous
(Fe2+) salts, are toxic to the gastrointestinal mucosa, and so intolerance is
common, resulting in poor compliance and failure of treatment. The sugar
derivative maltol strongly chelates iron, rendering it available for absorption
and stabilized in the less toxic ferric (Fe3+) form. AIM: To test whether ferric
trimaltol could correct iron deficiency anaemia in patients intolerant of ferrous
sulphate. METHODS: Twenty-three patients were recruited from gastroenterology
clinics, of whom 1 5 had inflammatory bowel disease, a group often difficult to
treat with oral iron. Patients with iron deficiency anaemia and documented
intolerance to ferrous sulphate were given 3 months of treatment with ferric
trimaltol. RESULTS: Nineteen of 23 patients completed the treatment and anaemia
was fully corrected in 14 of these, mean haemoglobin increased from 106 +/- 15 to
126 +/- 16 g/L, and there was a particularly low incidence of side-effects. Of 11
patients with inflammatory bowel disease who completed the study, nine fully
corrected their anaemia. CONCLUSION: The results demonstrate that in patients
intolerant of ferrous compounds, ferric trimaltol corrects iron deficiency and
has a low incidence of side-effects.
PMID- 9768527
TI - Effect of alosetron on responses to colonic distension in patients with irritable
bowel syndrome.
AB - BACKGROUND: Visceral hypersensitivity plays a major role in the pathophysiology
of irritable bowel syndrome, as shown by balloon distension studies. 5-HT3
receptors on afferent nerves may modulate visceral sensitivity and be the target
of new treatments for irritable bowel syndrome. AIM: To evaluate the effects of
alosetron, a potent and selective 5-HT3 antagonist, on the perception of colonic
distension by patients with irritable bowel syndrome, and on the colonic
compliance to distension with a barostat. METHODS: Twenty-five irritable bowel
syndrome patients were included in a randomized double-blind parallel group
trial; data were available for 22 (Rome criteria; 48 +/- 11 years: 13 men and
nine women). Patients were treated for 7 days with placebo (n = 6), alosetron
0.25 mg b.d. (n = 8) or alosetron 4 mg b.d. (n = 8). On day 6, a barostat bag was
placed in the left colon. On day 7, after an overnight fast, isobaric phasic
distensions were performed (4 mmHg steps, 5 min) up to the step triggering a
sensation of abdominal pain. RESULTS: Groups were comparable at inclusion (age,
sex, symptoms, bowel habits). There were no differences between treatment groups
in pressure recorded within the bag at the time of first sensation of abdominal
pain. However, bag volumes were significantly increased. At the first sensation
threshold, median volume differences of 61 mL and 90 mL (P = 0.028) were recorded
with alosetron 0.25 mg b.d. and 4 mg b.d., respectively. At the threshold of
abdominal pain, these differences were 71 mL (P = 0.039) and 84 mL (P = 0.017).
Colonic compliance increased from 5.9 mL/mmHg on placebo to 7.6 mL/mmHg on
alosetron 0.25 mg b.d. and to 9.8 mL/mmHg (P = 0.034) on alosetron 4 mg b.d.
CONCLUSION: Alosetron increases the compliance of the colon to distension, and
could thereby contribute to changes in perception of colonic distension and
improvement in the symptoms of irritable bowel syndrome.
PMID- 9768528
TI - Helicobacter pylori-positive peptic ulcer patients do not adapt to aspirin.
AB - BACKGROUND: Recent studies indicate that eradication of Helicobacter pylori might
prevent peptic ulcer formation in patients treated with non-steroidal anti
inflammatory drugs (NSAIDs). On the other hand, gastric adaptation after repeated
exposures to aspirin (ASA) is well documented but the influence of H. pylori on
this process remains to be elucidated. AIM: To compare gastric damage and
adaptation following repeated exposures to ASA in a group of patients with H.
pylori infection, before and after eradication of the bacterium, and in H. pylori
negative controls. METHODS: Eight healthy volunteers without H. pylori infection
and eight patients with duodenal ulcer (DU) history and H. pylori infection
before and after H. pylori eradication were given ASA 2 g/day for a period of 14
days. Mucosal damage was evaluated by endoscopy and histology of biopsy samples.
Gastric microbleeding, DNA synthesis in the gastric mucosa and mucosal
expression, as well as luminal content of transforming growth factor-alpha
(TGFalpha) were determined on days 0, 3, 7 and 14 of the ASA course. RESULTS: In
all patients aspirin-induced gastric damage reached a maximum on day 3. In H.
pylori-positive patients, this damage was maintained at a similar level up to day
14, whereas in H. pylori-negative controls and H. pylori-eradicated patients this
damage significantly lessened on day 14 and was accompanied by elevated DNA
synthesis as well as increased mucosal expression and luminal release of
TGFalpha.
PMID- 9768529
TI - Pantoprazole 20 mg is effective for relief of symptoms and healing of lesions in
mild reflux oesophagitis.
AB - AIM: To investigate the efficacy of a low dose of pantoprazole, a gastric proton
pump inhibitor, for the relief of symptoms and healing of lesions in mild gastro
oesophageal reflux disease (GERD), and to compare it with the efficacy of
ranitidine. METHODS: Patients with endoscopically established GERD (Stage I,
Savary-Miller classification) were enrolled into a randomized, double-blind,
parallel-group and multicentre study (intention-to-treat n = 209, age range 19-82
years). They were treated once daily with oral pantoprazole 20 mg or ranitidine
300 mg, for up to 8 weeks. End-point parameters included relief of symptoms
(heartburn, acid regurgitation, pain on swallowing) and the healing of GERD
lesions. Relief from symptoms was assessed after 2 and 4 weeks, and
endoscopically confirmed healing of lesions after 4 and 8 weeks. RESULTS: The
proportion of patients reporting complete relief from symptoms after 2 weeks was
greater in the pantoprazole than in the ranitidine group (69 vs. 48%, P < 0.01),
with further improvements seen in the pantoprazole group after 4 weeks (80 vs.
65%, P < 0.05, Cochran-Mantel/Haenszel test). Healing of lesions was confirmed in
70/87 (80%) patients after 4 weeks (pantoprazole group), as compared with 55/86
(64%) patients (ranitidine group) (P < 0.05, per protocol population); after 8
weeks the respective results were 78/87 (90%) and 63/86 (73%) patients (P <
0.01). Both study medications were well tolerated. CONCLUSION: Low-dose
pantoprazole (20 mg) is clinically superior to ranitidine (300 mg) in providing
fast relief from symptoms and healing of lesions in patients with mild GERD.
PMID- 9768530
TI - H2-antagonist maintenance therapy versus Helicobacter pylori eradication in
patients with chronic duodenal ulcer disease: a prospective study.
AB - BACKGROUND: Few outcome studies directly compare Helicobacter pylori eradication
therapy with maintenance H2-antagonist therapy in duodenal ulcer disease. AIM: To
examine prospectively the efficacy of H. pylori eradication therapy with
ranitidine maintenance therapy over 1 year in patients with confirmed chronic
duodenal ulcer. METHODS: One hundred and nineteen patients with active H. pylori
infection were randomized to receive ranitidine, 150 mg/day initially (58
patients), or omeprazole, 40 mg/day, amoxycillin 2 g/day and metronidazole 1.2
g/day for 14 days, or omeprazole 40 mg/day and clarithromycin 1.5 g/day, for 14
days (if penicillin-allergic). Symptoms were assessed using the Gastrointestinal
System Rating Scale (GSRS) and SF36 quality of life index. RESULTS: 13C urea
breath testing confirmed overall treatment success in 100% of patients (58/58)
per protocol and 95.1% (58/61) on an intention-to-treat basis. At 4 and 12 months
there were no differences in any GSRS symptoms between treatment groups. SF36
analysis showed a perceived health improvement at 4 and 12 months in patients who
received H. pylori eradication. However, despite successful H. pylori
eradication, one-fifth of patients still required antisecretory therapy.
CONCLUSION: Following successful H. pylori eradication, chronic duodenal ulcer
patients were at least as well symptomatically as when taking maintenance
ranitidine. They perceived that their health had improved, but a subgroup was
still acid-suppression dependent.
PMID- 9768531
TI - Helicobacter pylori eradication and ulcer healing with daily lansoprazole, plus 1
or 2 weeks co-therapy with amoxycillin and clarithromycin.
AB - BACKGROUND: Proton pump inhibitor based combination therapy is one standard
strategy for Helicobacter pylori eradication. AIM: To compare the eradication and
duodenal ulcer healing efficacy of two 2-week, single dose, lansoprazole based
combination therapies. METHODS: Healthy adult patients with endoscopically
confirmed, H. pylori associated duodenal ulcer disease (3 mm > ulcer < 20 mm)
were eligible for the study. All patients received a 14 day course of
lansoprazole 30 mg o.m., and were randomized to receive either 7 or 14 days of
amoxycillin 1 g b.d. and clarithromycin 500 mg b.d. Patients were endoscoped at
entry and 14-17 days later. Symptomatic, unhealed patients received a further 14
days of therapy with lansoprazole 30 mg o.m. Eradication was confirmed a minimum
of 28 days after cessation of all therapy by urease reaction and histological
assessment of gastric body and antral biopsies (three biopsies each site).
RESULTS: Sixty-two patients were randomized to a treatment arm, of which 58 could
be included in an intention-to-treat and key-point-available analysis. H. pylori
eradication rates were identical, at 93% (95% CI: 73-98% (1 week), 78-99% (2
week)). In the combined group, all but 13 ulcers were healed at 2 weeks; six
required further therapy because of symptoms, while six of the seven asymptomatic
patients went on to heal. CONCLUSION: An eradication regimen, based on a 2-week
course of single dose lansoprazole with 1 week of antibiotic co-therapy, is
effective in eradicating H. pylori, while the 2 weeks of acid suppression is
usually effective in duodenal ulcer healing.
PMID- 9768532
TI - Low rate of emergence of clarithromycin-resistant Helicobacter pylori with
amoxycillin co-therapy.
AB - BACKGROUND: Patients with persistent Helicobacter pylori infection following
treatment with clarithromycin or omeprazole plus clarithromycin often develop
clarithromycin resistance. AIM: To assess pre- and post-treatment antibiotic
resistance in three double-blind trials of triple therapy with omeprazole,
amoxycillin and clarithromycin. METHODS: Patients with H. pylori and duodenal
ulcer (studies 1 and 2) or history of duodenal ulcer (study 3) were randomly
assigned to 10 day courses of omeprazole 20 mg b.d., amoxycillin 1 g b.d. and
clarithromycin 500 mg b.d. (OAC) or placebo, amoxycillin 1 g b.d. and
clarithromycin 500 mg b.d. (AC). Endoscopy was performed at baseline and 4 weeks
after completion of therapy in studies 1 and 2, and at 4-6 weeks after therapy in
study 3. At baseline, H. pylori was diagnosed by CLO test with confirmation by
histology, or by culture. Eradication was defined as no positive biopsy test and
> or = 2 negative tests. Susceptibility testing was performed using the Etest.
RESULTS: In the 91 patients with pre-treatment susceptible isolates who had
persistent infection after AC, 10 developed resistance, eight had intermediate
susceptibility and 73 continued to have clarithromycin-susceptible H. pylori
isolates. In the 10 patients with pre-treatment susceptible isolates who had
persistent infection after OAC, three developed clarithromycin resistance and
seven still had susceptible isolates. CONCLUSIONS: Use of amoxycillin co-therapy
results in a low rate of clarithromycin resistance developing in patients with
persistent H. pylori infection following therapy with a clarithromycin-containing
regimen.
PMID- 9768533
TI - Continuous treatment with omeprazole 20 mg daily for up to 6 years in Barrett's
oesophagus.
AB - BACKGROUND: Because of the malignant potential of Barrett's oesophagus, an aim of
treatment is to cause the columnar epithelium to regress. A logical approach is
to decrease acid reflux which is an important aetiological factor in Barrett's
oesophagus. Treatment with omeprazole 20-80 mg over 1-3 years has yielded
conflicting but largely disappointing results. AIM: To determine if treatment of
Barrett's oesophagus with omeprazole 20 mg daily for up to 6 years can cause
regression of the Barrett's epithelium. PATIENTS AND METHODS: Forty-seven
patients with Barrett's oesophagus were treated in an open prospective study.
Nine patients were treated for 2 years, 12 for 3 years, 10 for 4 years, eight for
5 years and eight for 6 years. Patients were endoscoped at 1-2-year intervals and
endoscoped at the end of the treatment period. RESULTS: No significant shortening
of the length of the Barrett's segment was seen during any treatment period,
although omeprazole controlled reflux symptoms and was well tolerated.
Macroscopic squamous islands appeared in 55% of patients, mostly in the first 2-3
years although in five patients they appeared later in treatment. CONCLUSION:
Treatment of Barrett's oesophagus with omeprazole 20 mg daily for periods of up
to 6 years did not cause regression in the length of the Barrett's segment, but
it did lead in over half of the patients to partial re-epithelialization in the
form of squamous islands.
PMID- 9768534
TI - The effect of healing oesophagitis on oesophageal motor function as determined by
oesophageal scintigraphy and ambulatory oesophageal motility/pH monitoring.
AB - BACKGROUND: Oesophagitis has been shown by standard manometry to be associated
with impaired oesophageal motility, but it remains unclear if this abnormality
improves with healing of oesophagitis. AIM: To determine if healing of
oesophagitis improves oesophageal motility using solid bolus oesophageal transit
scintigraphy and combined ambulatory oesophageal motility/pH monitoring. METHODS:
Patients with grade II-III oesophagitis underwent ambulatory motility/pH
monitoring (using a Konigsberg catheter with four pressure transducers at 5 cm
intervals) and solid bolus scintigraphy before and after treatment with
omeprazole 20 mg b.d. for 8-14 weeks. RESULTS: Three (11%) of the 28 patients
failed to heal. Initial scintigraphy was abnormal in 18 (67%) of 27 patients (one
refused scintigraphy). Twenty-three of the 25 healed patients had repeat studies
showing no significant change in the number which were abnormal (16 (64%), P =
1.0) or the overall oesophageal transit time (P = 0.65). Due to intolerance of
the technique, only 11 patients had ambulatory motility/pH performed both before
and after healing, giving the study 90% power to detect a 5 mmHg increase in
peristaltic amplitude. No significant improvement was seen in any motility or pH
parameter after healing of oesophagitis. CONCLUSION: Analysis of oesophageal
motility showed no improvement in peristaltic activity after healing of
oesophagitis, suggesting that the abnormal motility is either a primary disorder
or an irreversible consequence of mucosal damage.
PMID- 9768535
TI - On-demand treatment of gastro-oesophageal reflux symptoms: a comparison of
ranitidine 75 mg with cimetidine 200 mg or placebo.
AB - AIM: To compare the effects of ranitidine 75 mg with those of either cimetidine
200 mg or placebo given on demand for relief of typical symptoms of gastro
oesophageal reflux disease during a 15-day period. METHODS: A total of 1336
patients (aged > or = 18 years) with heartburn episodes were recruited and
randomly assigned to a ranitidine 75 mg, cimetidine 200 mg or placebo group.
Depending on the occurrence or persistence of heartburn, treatment was
administered as required up to three times daily, with at least 2 h between drug
doses. Antacids were allowed as rescue medication if symptoms persisted for at
least 2 h after the third medication on any given day. The primary end-point was
defined as the proportion of patients with relief of at least 75% of heartburn
episodes during the study period (i.e. relief occurring within 2 h after drug
ingestion and lasting for at least 5 h). RESULTS: Analysis was performed in an
intention-to-treat population comprising 504 subjects in the ranitidine group,
515 in the cimetidine group and 270 in the placebo group. Primary end-point
success rates were 41, 38 and 28%, respectively, for the three groups (P < 0.001
for ranitidine vs. placebo, P = 0.274 for ranitidine vs. cimetidine). Ranitidine
75 mg was significantly more effective than placebo in providing overall
heartburn relief (P < 0.001). The differences between the ranitidine and
cimetidine groups were not significant, except for a greater reduction in
heartburn frequency in the ranitidine group at the end of the study period (P <
0.05). Drug dose was lower and less rescue medication was used in the ranitidine
group than the placebo group. The three treatment groups did not differ in terms
of tolerability. CONCLUSION: On-demand ranitidine 75 mg or cimetidine 200 mg are
safe and effective treatment for reflux-related symptoms.
PMID- 9768536
TI - Estimating the cost of lost productivity in dyspepsia.
AB - BACKGROUND: In the field of gastrointestinal disease, productivity costs are
highly relevant because work loss is substantial in dyspeptic patients.
Productivity costs are normally calculated by multiplying days absent valued by
gross earnings. This, however, might lead to an overestimation. AIM: To use a
conservative approach to calculating productivity costs, taking absence
compensating mechanisms into account. METHODS: Patients who visited their general
practitioner for the first time with dyspeptic complaints and patients who were
known to have persistent dyspeptic complaints were enrolled in two studies. In
total, 136 patients completed a questionnaire about their employment situation,
absence from work and absence compensating mechanisms. RESULTS: Sixty-six of the
respondents had a paid job, of which 25 (38%) reported absence from work during
the previous 4 weeks (average 3.0 days, 1.9 days related to dyspeptic
complaints). More than 50% of the employed respondents answered that absence
could be compensated for by colleagues, and only in 8% of the cases was absence
compensated for by overtime. Using our conservative approach, only one-quarter of
the productivity costs remained, compared to the current approach of valuing each
day absent as a loss of productivity. CONCLUSIONS: We suggest using both the
current and the conservative approaches, analogous to the principles of
sensitivity analysis, to avoid overestimation of productivity costs.
PMID- 9768537
TI - Experimental colitis induced by dextran sulphate sodium in mice: beneficial
effects of sulphasalazine and olsalazine.
AB - BACKGROUND: Animal models of inflammatory bowel disease are artificial and more
or less representative of human disease. However, the dextran sulphate sodium
(DSS) induced intestinal inflammation model has recently been shown to fulfil
some pathological criteria for an adequate experimental model. AIM: To determine
whether this form of experimental intestinal inflammation responds to established
therapy used for human inflammatory bowel disease. METHODS: DSS was used to
induce intestinal inflammation in conventional Balb/c mice and athymic nu/nu CD
1(BR) mice, and the well-documented 5-aminosalicylic acid (5-ASA) based
anticolitis drugs sulphasalazine (SASP) and olsalazine (OLZ) were used to study
therapeutic effects. Parameters which have been shown to reflect DSS-induced
intestinal inflammation (body weight, colon length, spleen weight, diarrhoea, and
rectal bleeding) were measured in the Balb/c mice. RESULTS: Significant
amelioration was seen on these parameters after different treatment protocols.
Survival in nu/nu CD-1 mice was studied, and after 16 days a death rate of 50%
was noted in the DSS group. SASP (100 mg/kg/day) and OLZ (50 mg/kg/day)
significantly prolonged the survival to 29 and 38 days, respectively. SASP and
OLZ showed a dose-dependent effect in the range between 10 and 100 mg/kg/day,
doses closely corresponding to those used in humans. CONCLUSIONS: SASP and OLZ
are able to ameliorate the DSS-induced intestinal inflammation. The dose-response
patterns suggested that the active therapeutic moiety for the two drugs appears
to be mainly the liberated 5-ASA molecule.
PMID- 9768538
TI - The role of GABA(A) receptors in the acute and chronic effects of ethanol.
AB - GABA(A) receptors are sensitive to ethanol in distinct brain regions and are
clearly involved in the acute actions of ethanol, ethanol tolerance, ethanol
dependence and ethanol self-administration. Data from a variety of perspectives
such as molecular, cellular and behavioral analysis have elucidated the role of
GABA(A) receptors in these processes. GABA(A) receptor activation mediates many
of the behavioral effects of ethanol including motor incoordination, anxiolysis
and sedation. The actions of ethanol at GABA(A) receptors are influenced by
endogenous modulators such as the neuroactive steroids. Sensitization to these
compounds influences ethanol dependence and withdrawal and may explain gender
differences in the molecular effects of ethanol. Furthermore, GABA(A) receptors
may also play a role in ethanol self-administration via the mesolimbic reward
system. Ethanol tolerance and dependence may be explained, in part, by changes in
the function of GABA(A) receptors. We have proposed that alterations in native
GABA(A) receptor subunit assembly could alter the functional properties of these
receptors. However, post-translational modifications or other post-synaptic
mechanisms may also explain changes in GABA(A) receptor function. Genetic animal
models of ethanol dependence have also identified GABA(A) receptor genes as
likely mediators of the behavioral adaptations associated with ethanol dependence
and withdrawal. A better understanding of the effects of ethanol at GABA(A)
receptors has highlighted important potential mechanisms involved in the
development of alcoholism.
PMID- 9768539
TI - Advances in development of medications for alcoholism treatment.
AB - Over the past decade, research on medications to treat alcohol problem has
flourished. Naltrexone and acamprosate are tangible fruits of such endeavors and
each has now earned approval in a large number of countries. Recent studies on
naltrexone indicate that patient compliance is important if full benefits are to
be achieved. Several laboratory studies with human subjects are beginning to
elucidate the mechanisms underlying efficacy of naltrexone, as well as explaining
variability of response among subpopulations of drinkers. In addition to these
two agents, recent investigations have also demonstrated that the antidepressants
desipramine, imipramine, and fluoxetine reduce mood-related symptoms and, to some
extent, drinking itself in alcoholics who are depressed. Research to date
suggests that opioid antagonists and selective serotonin reuptake inhibitors are
more effective in reducing alcohol intake when used in combination. Clinical
issues, methodology, and directions for future research are also reviewed in this
article. In particular, issues addressed include alternative dosage regimens,
necessary duration of treatment, employment of medications in combination,
integration of pharmacologic agents with behavioral interventions, enhancement of
patient compliance, and concurrent treatment of psychiatric comorbidity.
PMID- 9768540
TI - Role of hippocampus in alcohol-induced memory impairment: implications from
behavioral and immediate early gene studies.
AB - Acute alcohol intoxication disrupts memory acquisition in humans and laboratory
animals. This review summarizes recent behavioral and immediate early gene
expression studies addressing the mechanisms of this phenomenon. Most behavioral
investigations agree that the amnestic effect of alcohol is due to its
preferential detrimental effect on hippocampus-dependent than on hippocampus
independent forms of learning. However, some hippocampal lesion studies
contradict these results. Learning in behavioral paradigms is accompanied by
induction of c-fos and other immediate early genes in many brain regions of the
animal. In contrast, studies on alcohol-mediated changes in expression of this
gene confirm selective hippocampal suppression of basal and experience-induced
expression of c-fos after acute and repeated administration of alcohol. This
hippocampal suppression is in marked contrast with alcohol-mediated induction of
c-fos expression in other brain areas. However, the selective suppression of
hippocampal gene expression and memory by alcohol is most likely mediated by a
number of interacting neurotransmitter systems. Thus, effects of lower doses of
alcohol (0.5 g/kg or lower in rats) seem to be preferentially mediated through
GABAergic systems. At intermediate doses (0.75-2 g/kg), several other
neurotransmitter systems are affected besides GABA. Higher doses lead to none
specific effects, probably involving even more neurotransmitter systems.
Elucidation of these neurotransmitter systems will be highly important for
developing rational approaches for correction of alcohol-related cognitive
disorders.
PMID- 9768541
TI - Naltrexone treatment of comorbid alcohol and cocaine use disorders.
AB - Naltrexone (NTX) has been shown to be efficacious for the treatment of alcohol
dependence. Since alcohol and cocaine use disorders commonly co-occur, we
conducted a randomized, double-blind, placebo-controlled trial of NTX 50 mg/day
in 64 subjects with comorbid alcohol and cocaine use disorders. Although subjects
in both groups reduced their consumption of both alcohol and cocaine during the 8
week trial, there was no consistent advantage to NTX over placebo treatment. We
conclude that, due to behavioral, neurochemical, or other factors, individuals
with both alcohol and cocaine use disorders are distinct from those dependent on
alcohol alone, and that NTX at a dosage of 50 mg/day is not efficacious in this
patient population. Several factors, including medication dosage, length of
treatment, sample size and attrition rate, limit the interpretation of these
findings. Consequently, we recommend that subsequent trials of NTX to reduce the
risk of relapse in patients with comorbid alcohol and cocaine use disorders take
these issues into account.
PMID- 9768542
TI - Naltrexone reduces ethanol- and sucrose-reinforced responding in rhesus monkeys.
AB - These experiments evaluated the ability of naltrexone (NTX) to reduce selectively
oral and i.v. ethanol-reinforced responding, and examined the ethanol-NTX
interaction in terms of the competitive opioid antagonist property of NTX. Five
rhesus monkeys self-administered ethanol or sucrose and concurrently available
water. Ethanol concentration was varied from 0.25% to 8% (w/v). Naltrexone (0.032
0.32 mg/kg) or saline was given i.m. 30 min prior to some drinking sessions. NTX
(0.32 mg/kg) reduced ethanol-reinforced responding at the concentration that
maintained the most responding (1% or 2%). NTX (0.1 mg/kg) reduced ethanol
reinforced responding, both at a low ethanol concentration (0.25%) that produced
little ethanol intake (g/kg), and at a higher concentration (4%) with an
appreciable intake. Thus, NTX (0.1 mg/kg) shifted the ethanol concentration
consumption curve down, in an insurmountable manner. NTX (0.1 and 0.32 mg/kg)
also reduced reinforced responding for sucrose 100 g/l. In another experiment,
three rhesus monkeys were given opportunities to self-administer ethanol i.v. NTX
(0.1 mg/kg) reduced the number of ethanol injections obtained by the monkeys at
all ethanol doses tested (0.01, 0.032, and 0.1 g/kg per injection). The dose
effect curve was also shifted down. These results showed that NTX reduced
behavior maintained by either ethanol or sucrose non-selectively. Furthermore,
the ability of NTX to suppress ethanol-reinforced responding did not depend on
the route of ethanol administration and was not overcome by increasing the
concentration or dose per injection of ethanol.
PMID- 9768543
TI - Extinction of ethanol-induced conditioned place preference and conditioned place
aversion: effects of naloxone.
AB - Four experiments examined the effect of naloxone pretreatment on the expression
and extinction of ethanol-induced conditioned place preference (experiments 1, 2,
4) or conditioned place aversion (experiments 1, 3). DBA/2 J mice received four
pairings of a distinctive tactile (floor) stimulus (CS) with injection of ethanol
(2 g/kg) given either immediately before or after 5-min exposure to the CS. A
different stimulus was paired with injection of saline. Pre-CS injection of
ethanol produced conditioned place preference, whereas post-CS injection of
ethanol produced conditioned place aversion. Both behaviors extinguished
partially during repeated choice testing after vehicle injection. Naloxone (10
mg/kg) had little effect on the initial expression of conditioned place
preference, but facilitated its extinction. Moreover, repeated naloxone testing
resulted in the expression of a weak conditioned place aversion to the CS that
initially elicited a place preference. In contrast, naloxone (1.5 or 10 mg/kg)
enhanced expression of conditioned place aversion, thereby increasing its
resistance to extinction. A control experiment (experiment 4) indicated that
repeated testing with a different aversive drug, lithium chloride, did not affect
rate of extinction or produce an aversion to the CS previously paired with
ethanol. These findings do not support the suggestion that naloxone facilitates
the general processes that underlie extinction of associative learning. Also,
these data are not readily explained by the conditioning of place aversion at the
time of testing. Rather, naloxone's effects appear to reflect a selective
influence on maintenance of ethanol's conditioned rewarding effect, an effect
that may be mediated by release of endogenous opioids. Overall, these findings
encourage further consideration of the use of opiate antagonists in the treatment
of alcoholism.
PMID- 9768544
TI - Changes in the amygdala amino acid microdialysate after conditioning with a cue
associated with ethanol.
AB - Excitatory amino acid neurotransmission within the amygdala has been implicated
in learning associations between external stimuli and intrinsic reward values,
such that it may play a key role in conditioned drug effects. In the present
studies, the responses of the excitatory amino acids, aspartate and glutamate,
together with the neuromodulatory sulphonated amino acid, taurine, within the
basolateral amygdala, to an odor cue repeatedly associated with acute ethanol
injections (2 g/kg, i.p.) have been investigated by a microdialysis technique
combined with HPLC-EC analysis. After presentation of the ethanol-conditioned
stimulus, a single i.p. saline injection induced an immediate and significant
increase in the taurine microdialysate content which could be related to the
neuromodulatory action of taurine. Furthermore, when the conditioned stimulus was
combined with the ethanol injection (2 g/kg, i.p.), significant increases in both
taurine and glutamate microdialysate content were observed and indicated a
learned compensatory response to counteract the acute effects of ethanol. These
results demonstrate that changes in amygdala extracellular glutamate and taurine
concentrations can be conditioned to ethanol-associated stimuli and are therefore
probably implicated in the phenomenon of environmental-dependent tolerance to
ethanol.
PMID- 9768545
TI - Ethanol and negative feedback regulation of mesolimbic dopamine release in rats.
AB - The objectives of this study were to examine the relationship between
somatodendritic and terminal field dopamine (DA) release following manipulation
of DA D2 receptors in the ventral tegmental area (VTA), systemic administration
of ethanol, and inhibition of DA uptake in the nucleus accumbens (ACB). Perfusion
of 5, 25 and 100 microM quinpirole (a D2 agonist), or sulpiride (a D2 antagonist)
through the microdialysis probe in the VTA produced dose-related decreases or
increases, respectively, in the extracellular levels of DA in both the VTA and
ACB of adult Wistar rats. The IP administration of 2-3 g/kg ethanol produced a
sustained increase in the extracellular levels of DA (150-200% of baseline) in
the ACB for at least 2 h after injection, whereas only a transient increase was
observed in the VTA. Local perfusion of the ACB with 100 microM GBR12909, a DA
uptake inhibitor, elevated the extracellular levels of DA in the ACB to
approximately 400% of baseline, but decreased the extracellular levels of DA in
the VTA to approximately 50% of baseline. Overall, the results suggest that (a)
there is an association between somatodendritic and terminal field DA release
when D2 cell body autoreceptors in the VTA are manipulated, (b) elevating
synaptic levels of DA in the terminal field activates a long-loop negative
feedback system to the VTA, and (c) different mechanisms may be mediating the
actions of ethanol on DA neuronal activity and terminal DA release.
PMID- 9768546
TI - Pharmacological analysis of the heterogeneous discriminative stimulus effects of
ethanol in rats using a three-choice ethanol-dizocilpine-water discrimination.
AB - The present study used a three-choice operant drug discrimination procedure to
determine if NMDA-mediated discriminative stimulus effects could be separated
from other stimulus effects of 2.0 g/kg ethanol. Adult male Long-Evans rats (n =
7) were trained to discriminate dizocilpine (0.17 mg/kg; i.g.) from ethanol (2.0
g/kg; i.g.) from water (4.7 ml; i.g.) using food reinforcement. Substitution
tests were conducted following administration of the GABA(A) positive modulators
allopregnanolone (5.6-30.0 mg/kg; i.p.), diazepam (0.3-10.0 mg/kg; i.p.) and
pentobarbital (1.0-21.0 mg/kg; i.p.), the non-competitive NMDA antagonist
phencyclidine (0.3-10.0 mg/kg; i.p.), the 5-HT1 agonists TFMPP (0.3-5.6 mg/kg;
i.p.) and RU 24969 (0.3-3.0 mg/kg; i.p.), and isopropanol (0.10-1.25 g/kg; i.p.).
Allopregnanolone, diazepam and pentobarbital substituted completely (>80%) for
ethanol. Isopropanol partially (77%) substituted for ethanol. Phencyclidine
substituted completely for dizocilpine. RU 24969 and TFMPP did not completely
substitute for either training drug, although RU 24969 partially (62%)
substituted for ethanol. Successful training of this three-choice discrimination
indicates that the discriminative stimulus effects of 0.17 mg/kg dizocilpine were
separable from those of 2.0 g/kg ethanol. The finding that attenuation of NMDA
mediated effects of ethanol occurred without altering significantly GABA(A)- and
5-HT1-mediated effects suggests that the NMDA component may be independent of
other discriminative stimulus effects of 2.0 g/kg ethanol.
PMID- 9768547
TI - The discriminative stimulus effects of ethanol are mediated by NMDA and GABA(A)
receptors in specific limbic brain regions.
AB - This study was conducted to assess the involvement of N-methyl-D-aspartate (NMDA)
and gamma-aminobutyric acid (GABA) receptor systems, located in specific limbic
brain regions. in the discriminative stimulus effects of ethanol. Male Long-Evans
rats were trained to discriminate between intraperitoneal (i.p.) injections of
ethanol (1 g/kg) and saline on a two-lever drug discrimination task. The rats
were then implanted with bilateral injector guides aimed at the nucleus accumbens
core (AcbC), prelimbic cortex (PrLC), hippocampus area CA1 (CA1), or extended
amygdala (i.e., at the border of the central and basolateral nuclei). Infusions
of the non-competitive NMDA antagonist MK 801 in the AcbC or CA1 resulted in dose
dependent full substitution for i.p. ethanol. MK 801 infusion in the PrLC or
amygdala failed to substitute for ethanol. Injection of the competitive NMDA
antagonist CPP in the AcbC also failed to substitute for ethanol. Co-infusion of
MK 801 in the hippocampus potentiated the effects of MK 801 in the AcbC, whereas
NMDA infusion in the hippocampus attenuated the ability of MK 801 in the AcbC to
substitute for ethanol. The direct GABA(A) agonist muscimol resulted in dose
dependent full substitution for i.p. ethanol when it was injected into the AcbC
or amygdala, but failed to substitute when administered in the PrLC. Co-infusion
of MK 801, but not CPP, potentiated the effects of muscimol in the AcbC. These
results demonstrate that ethanol's discriminative stimulus function is mediated
centrally by NMDA and GABA(A) receptors located in specific limbic brain regions.
The data also suggest that the discriminative stimulus effects of ethanol are
mediated by interactions between ionotropic GABA(A) and NMDA receptors in the
nucleus accumbens, and by interactions among brain regions.
PMID- 9768548
TI - Blocking GABA(A) receptors in the anterior ventral tegmental area attenuates
ethanol intake of the alcohol-preferring P rat.
AB - The effect of blocking the A subtype of gamma-aminobutyric acid (GABA(A))
receptors in the anterior ventral tegmental area (VTA) on ethanol (EtOH; 10% v/v)
and saccharin (SACC; 0.0125%) consumption was investigated in alcohol-preferring
P rats. Picrotoxin (0.005, 0.01, 0.05 and 0.10 microg/0.5 microl) was injected
into the VTA, and consumption of EtOH and SACC was assessed in two 2-h limited
access drinking paradigms (concurrent EtOH/SACC access, and alternate-day-access
to EtOH and SACC). Under concurrent-access conditions, the picrotoxin
microinjections resulted in a 55 and 84% decrease in EtOH consumption at the 0.05
and 0.10 microg doses, respectively, compared with consumption following
microinjections of vehicle solution (P<0.05). Saccharin intake was not
significantly altered by picrotoxin. Under alternate-day-access drinking
conditions, the picrotoxin microinjections resulted in dose-dependent decreases
in EtOH consumption of 37-68%, with significant decreases following the 0.005,
0.05 and 0.10 microg doses (P<0.04). Saccharin intake was significantly reduced
only at the 0.05 microg dose. The decrease in EtOH consumption after 0.10 microg
picrotoxin was attenuated by co-administration of 0.01 microg muscimol. This dose
of muscimol had no effect on EtOH consumption when injected alone. Intra-VTA
injections of bicuculline (0.04 microg), another GABA(A) antagonist, reduced EtOH
intake, comparable to the reduction following 0.10 microg picrotoxin.
Microinjections of 0.10 microg picrotoxin in regions outside the VTA failed to
decrease EtOH intake. These results suggest that anterior VTA mechanisms
regulating alcohol drinking behavior are under tonic GABA inhibition, mediated by
GABA(A) receptors. The results also suggest that different neural mechanisms are
regulating voluntary EtOH and SACC drinking behaviors.
PMID- 9768549
TI - Dissociation of consummatory and vocal components of feeding in squirrel monkeys
treated with benzodiazepines and alcohol.
AB - The primary aim of the current experiments was to develop methods that engender
vocalizations associated with positive social situations comprising affiliative
behavior and feeding that could be quantified under controlled laboratory
conditions and were sensitive to anxiolytic drugs. Classical conditioning
procedures were used to elicit vocalizations during presentation of stimulus
lights (i.e., CS condition) previously paired with either preferred foods (e.g.,
grapes, peanuts, bananas) or standard foods (e.g., monkey chow) as well as during
presentation of both food types (i.e., UCS condition). When compared to the
period before stimulus light presentation (i.e., Pre-CS condition), the rate,
duration and number of elemental units of food-related "twitter" vocalizations
were increased during the CS conditions regardless of food type. Monkeys spent
significantly more time oriented toward the food box during the light stimulus
that preceded preferred food than for the light stimulus that preceded standard
food. However, twitter vocalizations were higher for standard food regardless of
the stimulus conditions (i.e., Pre-CS, CS and UCS). Administration of the
benzodiazepine full agonist chlordiazepoxide (CDP, 1-10 mg/kg), the partial
agonist bretazenil (BRZ, 1-10 mg/kg), the antagonist flumazenil (FLZ, 1-10 mg/kg)
and ethyl alcohol (EtOH, 0.1-1.0 g/kg) differentially altered vocalizations.
Although CDP and BRZ increased feeding of standard food, twitters were reduced
across stimulus conditions. CDP and BRZ did not alter other social contact calls
(i.e., "peeps"). FLZ also reduced twitters without altering peeps, but did not
increase feeding. In contrast, EtOH did not increase feeding or peeps, but did
increase food-related twitters. These results indicate that there is a
dissociation between food-related behaviors, such as food consumption and
orientation towards the food source, and vocal behaviors associated with group
communication during feeding.
PMID- 9768550
TI - Effects of third intracerebroventricular injections of corticotropin-releasing
factor (CRF) on ethanol drinking and food intake.
AB - Corticotropin releasing factor (CRF), a neuropeptide secreted by hypothalamic and
extrahypothalamic neurons, is thought to mediate stress-related behaviors. The
tension reduction hypothesis suggests that ethanol drinking reduces stress; that
drinking is reinforced by this reduced stress; and that the probability of
drinking therefore subsequently increases. CRF also decrease food intake, and
might decrease ethanol drinking similarly. We addressed these hypotheses directly
by assessing the effects of intracerebroventricular (i.c.v.) CRF upon ethanol
drinking (1 h/day). Rats were provided drinking tubes containing ethanol
solutions that were gradually incremented in concentration (from 2% to 8% w/v,
over 38 days). Ethanol intakes remained stable, ranging from 0.4 to 0.5 g/kg per
hour on average, and a two-bottle choice test revealed that ethanol was preferred
reliably to water. Third-i.c.v. cannulae were surgically implanted and CRF or
vehicle was acutely injected immediately prior to the sessions. CRF dose
dependently reduced ethanol intake by 31% (0.5 microg) and 64% (5.0 microg), and
reduced 24-h food by 9% and 21%, respectively, but did not alter body weights.
I.c.v. CRF reduced ethanol drinking despite any acute stress-like effects that
may have been present. Hence, these data are inconsistent with the tension
reduction hypothesis. On the other hand, our results support the concept that
food intake and ethanol drinking may be mediated by similar mechanisms.
PMID- 9768551
TI - Are some of the effects of ethanol mediated through NPY?
AB - Central administration of neuropeptide Y (NPY) in low concentrations has been
shown to produce anxiolysis and suppression of locomotor activity, a behavioral
profile not dissimilar to that of ethanol. The present study was conducted to
ascertain whether NPY and ethanol have similar electrophysiological profiles and
to evaluate the combined actions of NPY and ethanol. Eighty-five Wistar rats were
stereotaxically implanted with electrodes aimed at dorsal hippocampus, amygdala,
and frontal cortex. Rats were administered NPY [or saline (SAL)]
intracerebroventricularly (i.c.v.) whereas the doses of alcohol (or SAL) were
given intraperitoneally (i.p.). Two doses of alcohol (0.75, 1.5 g/kg) and two
doses of NPY (1, 3 nmol) were given alone and in combination. Drug effects were
assessed using event related potentials (ERP) recorded in response to an auditory
"oddball" plus noise paradigm between 30 and 40 min post-drug. Multivariate
analyses of variance (MANOVA) revealed that NPY produced a significant decrease
in the amplitude and increase in the latency of the N1 component in cortex and a
decrease in the amplitude of the P3 component in amygdala, but no overall effects
in hippocampus. Ethanol produced identical effects to NPY on the N1 and P3
components of the ERP in cortex and amygdala. Combined administration of EtOH and
NPY (1 nmol) produced effects equivalent to those seen following the higher doses
of NPY (3 nmol) or EtOH (1.5 g/kg). These studies demonstrate that NPY and
ethanol have a similar electrophysiological profile. In addition, the combined
administration of NPY and ethanol produced additive effects.
PMID- 9768552
TI - Repeated ethanol withdrawal experience selectively alters sensitivity to
different chemoconvulsant drugs in mice.
AB - Repeated ethanol withdrawal experience has been shown to result in exacerbated
seizures associated with future withdrawal episodes. This sensitization of the
withdrawal response has been postulated to represent a "kindling" phenomenon. The
present study employed an established model of repeated ethanol withdrawals to
examine the potential role of GABA(A), and NMDA and non-NMDA glutamate receptor
systems in mediating enhanced seizure activity, as assessed by sensitivity to
seizures induced by pentylenetetrazol (PTZ), NMDA, and kainic acid (KA) i.v.
infusions, respectively. Adult C3H mice were chronically exposed to ethanol vapor
in inhalation chambers. A multiple withdrawal (MW) group received four cycles of
16-h ethanol vapor exposure interrupted by 8-h periods of abstinence; a single
withdrawal (SW) group was tested after a single 16-h bout of ethanol
intoxication; and the third group was ethanol-naive, serving as controls (C).
Results indicated that the MW group evidenced significantly lower PTZ and NMDA
seizure thresholds compared to SW and C groups at 8 and 24 h post-withdrawal. In
contrast, MW and SW groups exhibited reduced sensitivity (higher seizure
threshold) to KA in comparison to controls, and this effect only emerged at 24 h
post-withdrawal. Further, MW mice required significantly less additional PTZ or
NMDA to induce more severe convulsions once initial signs of seizures were
elicited. Conversely, latency and amount of KA required to transition from
initial seizure signs to more severe end-stage convulsions was significantly
greater for MW and SW groups compared to controls. Taken together, these results
suggest that repeated ethanol withdrawal experience does not result in a global
non-specific lowering of threshold to convulsive stimuli, but rather, selective
changes in CNS mechanisms associated with neural excitability may underlie
potentiated withdrawal responses. Thus, reduced GABA(A) receptor function and
increased NMDA receptor activity may become exaggerated as a consequence of
repeated withdrawal experience, while reduced sensitivity to KA induced seizures
may represent a compensatory response to withdrawal-related CNS
hyperexcitability.
PMID- 9768553
TI - Effects of ethanol on Pavlovian autoshaping in rats.
AB - Approach responses, consummatory behaviors, and directed motor responses
maintained by food reward resemble autoshaping CRs and are increased by lower
doses of ethanol. This study evaluated the effects of presession i.p. injections
of ethanol doses (0.00, 0.25, 0.50, 0.70. or 1.00 g/kg) on the acquisition of
lever-press autoshaping CR performance in groups of male Long-Evans hooded rats.
Paired groups received 15 daily sessions of Pavlovian autoshaping procedures,
wherein the insertion of a retractable lever for 5 s (CS) was followed by the
response-independent presentation of food (US). Ethanol facilitated lever-press
autoshaping CR acquisition, as revealed by dose-related increases in the number
of trials on which CRs were performed. The form of the dose-effect curve was
inverted U-shaped with maximal responding induced during sessions 1-5 by the 0.70
g/kg ethanol dose. A similar dose-effect curve was observed during sessions 11
15, revealing that the effects of ethanol on autoshaping CR performance were
relatively stable. A pseudoconditioning control group injected presession with
0.50 g/kg ethanol received training wherein the food US was presented randomly
with respect to the lever CS. Few lever-presses were performed by the Random 0.50
group, indicating that ethanol's effects on autoshaping CR acquisition and
maintenance observed in the Paired 0.50 group were not due to its psychomotor
activating effects. A non-injection control group performed more autoshaping CRs
than did the control group injected presession with saline, indicating that daily
presession i.p. injections per se suppress autoshaping CR performance. Results
reveal that low doses of ethanol enhance Pavlovian conditioning of directed motor
and consummatory-like responding maintained by food reward. Implications for
autoshaping accounts of impulsivity and drug abuse are considered.
PMID- 9768554
TI - Alcohol-heightened aggression in mice: attenuation by 5-HT1A receptor agonists.
AB - One of the critical mechanisms by which alcohol heightens aggression involves
forebrain serotonin (5-HT) systems, possibly via actions on 5-HT1A receptors. The
present experiments tested the hypothesis that activating 5-HT1A receptors by
selective agonists will block the aggression-heightening effects of ethanol.
Initially, the selective antagonist WAY 100635 was used to assess whether or not
the changes in aggressive behavior after treatment with 8-OH-DPAT and flesinoxan
result from action at the 5-HT1A receptors. Resident male CFW mice engaged in
aggressive behavior (i.e. attack bites, sideways threats, tail rattle) during 5
min confrontations with a group-housed intruder male. Quantitative analysis of
the behavioral repertoire revealed systematic reductions in all salient elements
of aggressive behavior after treatment with 8-OH-DPAT (0.1-0.3 mg/kg, i.p.) or
flesinoxan (0.1-1.0 mg/kg, i.p.). The 5-HT1A agonists also reduced motor
activities such as walking, rearing and grooming, although to a lesser degree.
Pretreatment with the antagonist WAY 100635 (0.1 mg/kg, i.p.) shifted the agonist
dose-effect curves for behavioral effects to the right. In a further experiment,
oral ethanol (1.0 g/kg, p.o.) increased the frequency of attacks in excess of 2
SD from their mean vehicle level of attacks in 19 out of 76 resident mice. Low
doses of 8-OH-DPAT (0.03-0.3 mg/kg) and flesinoxan (0.1, 0.3, 0.6 mg/kg), given
before the ethanol treatment, attenuated the alcohol-heightened aggression in a
dose-dependent fashion. By contrast, these low 5-HT1A agonist doses affected
motor activity in ethanol-treated resident mice to a lesser degree, suggesting
behavioral specificity of these anti-aggressive effects. The current results
support the hypothesized significant role of 5-HT1A receptors in the aggression
heightening effects of alcohol. If these effects are in fact due to action at
somatodendritic 5-HT1A autoreceptors, then the anti-aggressive effects would be
associated with decreased 5-HT neurotransmission.
PMID- 9768555
TI - Relationship between anticonvulsant activity and plasma level of some 2,3
benzodiazepines in genetically epilepsy-prone rats.
AB - The anticonvulsant effects of some novel 2,3-benzodiazepines acting as alpha
amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid/kainate (AMPA/KA) antagonists
were evaluated in genetically epilepsy prone rats. The ED50 values against clonic
and tonic seizures (in micromol/kg) revealed that the rank order of
anticonvulsant activity was: GYKI 52466 > 2,3BZ-2 > 2,3 MBZ-2 > NBQX. Maximal
anticonvulsant protection was observed 15-45 min after the i.p. administration of
NBQX and GYKI 52466, 30-90 min after the i.p. administration of 2,3BZ-2, and 45
120 min after the i.p. administration of 2,3MBZ-2. The time course of plasma
levels of rats treated with GYKI 52466 showed that peak plasma concentration was
observed 15 min after i.p. administration, 2,3BZ-2 revealed that peak plasma
concentration was achieved 45 min after i.p. administration, whereas following
2,3MBZ-2 administered i.p., two curves were detected; one is referred to the
parent compound and the other to its demethylate metabolite that corresponds to
2,3BZ-2. The therapeutic index (ratio of TD50 values for impaired rotarod
performance and ED50 values for anticonvulsant activity) revealed that NBQX and
GYKI 52466 were slighly more toxic than 2,3BZ-2 and 2,3MBZ-2. The present data
suggest that 2,3-benzodiazepines acting at AMPA/kainate receptors play an
important role in the generation and/or propagation of the audiogenic seizures in
genetically epilepsy-prone rats.
PMID- 9768556
TI - Effects of LHRH on avoidance conditioning in normally cycling and ovariectomized
female rats.
AB - Several studies have demonstrated that the peptide LHRH can modify behavior in
the male rat. Peripheral and intracerebral infusions of LHRH impair the
acquisition of conditioned avoidance responses (CARs) and increase some
spontaneous motor behaviors, such as head shaking and grooming. The present study
was undertaken to detect the effects of LHRH on the acquisition of CARs and
spontaneous motility in normally cycling and ovariectomized (OVX) Sprague-Dawley
female rats. Normally cycling females were separated in four groups, according to
the stage of the estrous cycle. Ovariectomized female rats were pretreated, 48 h
before the experiment, with estradiol benzoate (10 microg/kg) or corn oil. LHRH
(6.25, 25, or 50 microg/kg) was subcutaneously injected and the behavioral tests
began 1 h after. Low doses of LHRH stimulated the acquisition of CARs during
proestrus, estrus, and metestrus, whereas higher doses impaired conditioning in
all the four stages of the cycle. High doses of LHRH impaired acquisition in OVX
rats treated with oil and potentiated the depressant effects of EB on this
behavior. The effects of LHRH on spontaneous motor activity were either
stimulatory or inhibitory, according to the hormonal status and the dose
administered. High doses of LHRH decreased motor responses in the diestrous rat.
All the doses of LHRH increased the number of headshakes during proestrus,
estrus, and metestrus, while the other motor responses were scarcely or not
affected by LHRH in these stages. In OVX rats LHRH increased rearing, head
shaking, and grooming behavior. These results support a role of LHRH in the
modulation of conditioned and spontaneous behavior. They could provide an
explanation to the behavioral changes observed across the estrous cycle and those
observed after EB priming in OVX rats.
PMID- 9768557
TI - Maternal exposure to low doses of delta9-tetrahydrocannabinol facilitates
morphine-induced place conditioning in adult male offspring.
AB - The possible existence of an increased susceptibility to the reinforcing
properties of morphine was analyzed in male and female rats born from mothers
exposed to delta9-tetrahydrocannabinol (THC, 1, 5, or 20 mg/kg) during gestation
and lactation. Maternal exposure to low doses of THC (1 and 5 mg/kg), relevant
for human consumption, resulted in an increased response to the reinforcing
effects of a moderate dose of morphine (350 microg/kg), as measured in the place
preference conditioning paradigm (CPP) in the adult male offspring. These animals
also displayed an enhanced exploratory behavior in the defensive withdrawal test.
However, only females born from mothers exposed to THC 1 mg/kg exhibited a small
increment in the place conditioning induced by morphine. The possible implication
of the hypothalamo-pituitary-adrenal axis (HPA) was analyzed by monitoring plasma
levels of adrenocorticotropic hormone (ACTH) and corticosterone in basal and
moderate-stress conditions (after the end of the CPP test). Female offspring
perinatally exposed to THC (1 or 5 mg/kg) displayed high basal levels of
corticosterone and a blunted adrenal response to the HPA-activating effects of
the CPP test. However, male offspring born from mothers exposed to THC (1 or 5
mg/kg) displayed the opposite pattern: normal to low basal levels of
corticosterone, and a sharp adrenal response to the CPP challenge. The present
study reveals that maternal exposure to low doses of THC results in an increased
sensitivity to the reinforcing effects of morphine in the adult male offspring,
and in sexually dimorphic behavioral and endocrine alterations in the adaptative
responses to stressors such as novelty or place-preference testing. These results
support the growing evidence of the importance of monitoring the long-term
consequences of maternal consumption of cannabis derivatives.
PMID- 9768558
TI - Pharmacological characterization of 6-bromo-3'-nitroflavone, a synthetic
flavonoid with high affinity for the benzodiazepine receptors.
AB - 6-Bromo-3'-nitroflavone is a synthetic flavone derivative that selectively
recognizes benzodiazepine receptors and has potent anxiolytic-like effects. Here,
we describe in detail its pharmacological characterization. When i.p. injected in
mice, 6-bromo-3'-nitroflavone (0.01-0.3 mg/kg) had an anxiolytic-like effect in
the elevated plus-maze test. This effect was blocked by the specific
benzodiazepine receptor antagonist, flumazenil. In addition, it exhibited
anxiolytic-like actions when given orally (1 mg/kg). 6-Bromo-3'-nitroflavone did
not exhibit myorelaxant effects (up to 30 mg/kg, i.p.). Unlike diazepam, this
flavonoid produced no anterograde amnesia in a one-trial inhibitory avoidance
learning. On the other hand, 6-bromo-3'-nitroflavone possessed mild
anticonvulsant activity (0.1 mg/kg, i.p.) and provoked sedative-depressant
actions only at doses 100-1000 times higher than those producing anxiolytic-like
effects. 6-Bromo-3'-nitroflavone (0.1-1 mM) produced a lower potentiation of
gamma-amino-butyric acid (GABA)-stimulated 36Cl- influx (126-138%) in comparison
to diazepam (0.1 mM: 166%) in cerebral cortical membrane vesicles. Taken
together, these findings suggest that 6-bromo-3'-nitroflavone has anxiolytic-like
action possibly behaving as a partial agonist of the benzodiazepine receptors.
PMID- 9768559
TI - Beneficial effects of acute and repeated administrations of sigma receptor
agonists on behavioral despair in mice exposed to tail suspension.
AB - In an attempt to examine whether sigma receptor agonists alleviate behavioral
despair, we investigated the effects of sigma receptor agonists on the tail
suspension-induced immobility in mice. The acute and repeated (14 days)
administrations of sigma1 receptor agonists, such as 1-(3,4-dimethoxyphenethyl)-4
(3-phenylpropyl)piperazine dihydrochloride (SA4503) (1 and/or 3 mg/kg) and (+)
pentazocine (5.6 mg/kg), sigma1/2 receptor agonists, such as 1,3-di(2
tolyl)guanidine (DTG) (3 and/or 5.6 mg/kg), desipramine (7.5 and/or 15 mg/kg),
and fluoxetine (10 and/or 20 mg/kg), reduced immobility in mice exposed to tail
suspension. N,N-Dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl] ethylamine
monohydrochloride (NE-100), a sigma1 receptor antagonist, significantly
antagonized the decrease in immobility induced by acute administrations of SA4503
(1 mg/kg) and (+)-pentazocine (5.6 mg/kg). Although not significant, NE-100
showed a tendency to inhibit the DTG (5.6 mg/kg)-induced decrease in immobility.
In contrast, repeated administrations of SA4503 (1 and 3 mg/kg), (+)-pentazocine
(5.6 mg/kg) or DTG (5.6 mg/kg) failed to affect the increase in body weight.
These results suggest that acute and repeated stimulations of sigma, possibly a
sigma1 receptor subtype, alleviate behavioral despair, unaccompanied with changes
in body weight.
PMID- 9768560
TI - Behavioral pharmacology of zolpidem relative to benzodiazepines: a review.
AB - Zolpidem, an imidazopyridine that purportedly binds selectively to certain
GABA(A) receptor subtypes, is the most commonly prescribed hypnotic. The present
article critically reviewed the extant experimental literature to determine
whether the behavioral pharmacologic profile of zolpidem also differs from that
of benzodiazepines. Specific topics that are reviewed include: 1) reinforcing
effects and abuse potential, 2) discriminative-stimulus effects, 3) subject-rated
drug effects, 4) performance-impairing effects, 5) tolerance-producing effects,
and 6) physiological dependence-producing effects. Studies that employed both
nonhumans and humans are reviewed. Based on the available literature, the most
parsimonious conclusion is that despite its unique neuropharmacological profile,
the behavioral effects of zolpidem are generally similar to those of
benzodiazepines. However, it is important to note the dearth of perspective,
experimental studies that directly compared zolpidem and a benzodiazepine.
Because of the clinical relevance and paucity of published studies, future
research should focus explicitly on assessing the reinforcing effects, abuse
potential, performance-impairing effects, tolerance-producing effects, and
dependence-producing effects of zolpidem relative to a benzodiazepine. Important
issues such as the selection of an appropriate comparison drug and subject
population, and the doses tested needed to be considered in these future studies.
PMID- 9768561
TI - The effects of inhaled isoparaffins on locomotor activity and operant performance
in mice.
AB - Very little is known qualitatively or quantitatively about the acute central
nervous system effects of isoparaffin solvents that are widely used in household
and commercial applications. Four isoparaffinic hydrocarbon solvent products
differing in predominant carbon number and volatility (ISOPAR-C, -E -G, -H) were
tested for their acute effects on locomotor activity and operant performance
after inhalation exposure in mice. For both measures, concentration-effect curves
were obtained for 30-min exposures using a within-subject design. The more
volatile products, ISOPAR-C and -E, were as easily vaporized under our conditions
as vapors such as toluene and TCE, which have acute effects on human behavior and
are abused. ISOPAR-G was slowly volatilized and ISOPAR-H could not be completely
volatilized within our 30-min exposures, suggesting that acute human exposures
may be less likely and that it may be more difficult to abuse them. ISOPAR-C, -E,
and -G produced reversible increases in locomotor activity of mice at 4000 and
6000 ppm while ISOPAR-C and -E produced reversible concentration-dependent
decreases in rates of schedule-controlled operant behavior in approximately the
same concentration range as they affected locomotor activity. The fact that only
locomotor activity increases were observed with these isoparaffins provides
evidence that they produce a different pattern of effects than those reported for
abused solvents such as toluene and TCE. Further research will be needed to
determine if this different pattern of effects on animal behavior between
isoparaffins and abused solvents is correlated with a different pattern of acute
intoxication and abuse potential in humans.
PMID- 9768562
TI - Nicotine administration impairs sensory gating in Long-Evans rats.
AB - In rats, effects of nicotine administration on sensory gating as indexed by
prepulse inhibition (PPI) of the acoustic startle reflex (ASR) are unclear. We
have found that nicotine administration enhances ASR and PPI in Sprague-Dawley
rats, but other investigators, using Long-Evans rats, have reported no effects or
enhancement of PPI only. Numerous methodological differences exist among studies
in addition to subject strain, however, making it unclear whether inconsistent
behavioral responses are the result of different experimental procedures or
indicate a true strain difference. To investigate the role of strain in
nicotine's effects on ASR and PPI, 192 male and female Long-Evans rats were
administered 12 mg/kg/day nicotine via osmotic minipump for 14 days using
identical methodologies employed in studies with Sprague-Dawley subjects. Effects
of grouped vs. individual housing on these responses also were examined. Nicotine
administration impaired ASR and PPI in Long-Evans subjects. These effects
occurred in female rats regardless of housing condition, and interacted with
housing in male rats. Results indicate that sex and housing are important
variables in nicotine's effects. Results suggest that subject strain may be an
important variable in nicotine's effects on sensory gating, and that responses of
Sprague-Dawley vs. Long-Evans rats may represent a true strain difference.
PMID- 9768563
TI - Cocaine and caffeine: conditioned place preference, locomotor activity, and
additivity.
AB - Conditioned place preference (CPP) was employed to clarify the reinforcing and
locomotor stimulating effects of several doses of cocaine and caffeine (0.32,
1.0, 3.2, 5.6, and 10.0 mg/kg) and to explore the possibility of additive effects
between the two drugs. Additionally, the hypothesis that the reinforcing effects
of psychostimulants are mediated by the same systems that control psychostimulant
induced locomotor activity was examined by conducting correlational studies
between drug-induced locomotor activity and time spent in the drug-conditioned
compartments. Several doses of cocaine (1.0, 3.0, 5.6, 10.0 mg/kg), and caffeine
(0.32, 1.0, 3.2, 5.6, 10.0) were found to condition place preference and
stimulate locomotor activity. A combination of low doses (0.32 mg/kg) of each
drug appeared to be additive. A positive relationship between locomotor activity
observed during conditioning and time spent in the conditioned compartment during
testing was found for cocaine but not caffeine or the low-dose combination of
cocaine and caffeine.
PMID- 9768564
TI - The synergistic effects of combining cocaine and heroin ("speedball") using a
progressive-ratio schedule of drug reinforcement.
AB - The relative reinforcing value of cocaine/heroin combination ("speedball") was
compared in the rat using a progressive-ratio (PR) reinforcement schedule. The
initial training for all rats was a combined dose of 18 microg/kg/inj of heroin
(H) plus 300 microg/kg/inj of cocaine (C). Break points for the training dose and
individual component doses were determined for half and double the training dose.
Of the three doses of each treatment, only C yielded the expected monotonic
increase in break point as a function of dose. Also, break points for C (300 and
600 microg/kg/inj) was greater than for the combination of C and H (18 H/300 C
and 36 H/600 C microg/kg/inj), suggesting a greater reward value for C alone. The
doses for these three drug treatments that produced saline level break points
were then determined. At these lower doses, significant break points were
obtained with the H/C combination at which the respective doses of H or C had
break points identical to those of saline. These lower dose results indicate that
the combination is clearly synergistic and that the discrepancy with doses at the
opposite end of the dose response curve suggest that the PR schedule is
vulnerable to drug-induced motor effects.
PMID- 9768565
TI - Phase-response curve for ethanol: alterations in circadian rhythms of temperature
and activity in rats.
AB - Circadian rhythms of core body temperature and general activity in Sprague-Dawley
rats were monitored for 21 days using remote radiotelemetry to examine acute and
sustained effects of 0 (saline) 1.0, and 2.0 g/kg ethanol injections administered
at four different times of day. Ethanol produced dose-dependent and statistically
significant hypothermia and hypoactivity when injected at 0100, 0700, 1300, and
1900 h; however, the magnitude of the hypothermic effect was greatest at the 1900
h injection time. Cosinor analyses revealed persistent alterations in both
activity and temperature rhythms, which lasted for at least 48 h postinjection.
Ethanol significantly shortened the period of activity rhythms when injected in
either 1.0 or 2.0 g/kg doses at 0700 and 1300 h, and produced similar period
shortening effects on temperature rhythms at 1300 and 1900 h. The acrophase of
the activity rhythm was significantly phase delayed by 1.0 g/kg ethanol at 0700
h, while the acrophase of temperature was significantly phase advanced by 2.0
g/kg ethanol at 0100 h, but significantly phase delayed by the same dose
administered at 1300 h. A statistically significant and dose-dependent reduction
in the amplitude of the body temperature rhythm was observed at the 1900-h
administration time. There were no differences in the MESOR (Midline Estimating
Statistic of Rhythm; i.e., rhythm-adjusted mean value) of either temperature or
activity circadian rhythms as a function of ethanol treatment at any dose.
PMID- 9768566
TI - Failure of clonidine to stimulate feeding in healthy humans.
AB - The alpha2-adrenergic system is involved in the regulation of food intake in
animals but its effects on feeding in humans are unknown. We hypothesized that
clonidine administration would stimulate food intake in healthy human subjects.
Ten men and 4 women, all physically and psychiatrically healthy, received
clonidine 3 microg/kg or placebo, orally, in blinded, balanced, randomized order.
Consumption of a liquid test meal was measured; also, serum growth hormone levels
were used as a secondary measure of clonidine effects. Visual analog scale
ratings of hunger, satiety, and sedation were obtained before, during, and after
the test meal. A subset of five subjects also received 1.5 microg/kg clonidine,
in addition to the two trials described above. Test meal consumption was greater
following placebo than following clonidine. Sedation ratings were substantially
higher at all time points after clonidine and correlated with meal consumption
(correlation coefficient r = -0.584; p = 0.028). Hunger and satiety ratings did
not differ. The 1.5 microg/kg dose did not provide different effects on feeding
from that seen with placebo. Contrary to our hypothesis, clonidine did not
stimulate food intake in humans. Sedation associated with clonidine
administration may have suppressed any effects on feeding.
PMID- 9768567
TI - Agonist properties of N,N-dimethyltryptamine at serotonin 5-HT2A and 5-HT2C
receptors.
AB - Extensive behavioral and biochemical evidence suggests an agonist role at the 5
HT2A receptor, and perhaps the 5-HT2C receptor, in the mechanism of action of
hallucinogenic drugs. However the published in vitro pharmacological properties
of N,N-dimethyltryptamine (DMT), an hallucinogenic tryptamine analog, are not
consistent with this hypothesis. We, therefore, undertook an extensive
investigation into the properties of DMT at 5-HT2A and 5-HT2C receptors. In
fibroblasts transfected with the 5-HT2A receptor or the 5-HT2C receptor, DMT
activated the major intracellular signaling pathway (phosphoinositide hydrolysis)
to an extent comparable to that produced by serotonin. Because drug efficacy
changes with receptor density and cellular microenvironment, we also examined the
properties of DMT in native preparations using a behavioral and biochemical
approach. Rats were trained to discriminate an antagonist ketanserin from an
agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) in a two-lever choice
paradigm. Pharmacological studies showed that responding on the DOI and
ketanserin lever reflected agonist and antagonist activity at 5-HT2A receptors,
and hence, was a suitable model for evaluating the in vivo functional properties
of DMT. Like other 5-HT2A receptor agonists, DMT substituted fully for DOI.
Intact choroid plexus was used to evaluate the agonist properties at endogenous 5
HT2C receptors; DMT was a partial agonist at 5-HT2C receptors in this native
preparation. Thus, we conclude that DMT behaves as an agonist at both 5-HT2A and
5-HT2A receptors. One difference was evident in that the 5-HT2C, but not the 5
HT2A, receptor showed a profound desensitization to DMT over time. This
difference is interesting in light of the recent report that the hallucinogenic
activity of DMT does not tolerate in humans and suggests the 5-HT2C receptor
plays a less prominent role in the action of DMT.
PMID- 9768568
TI - Naloxone-precipitated morphine withdrawal induced place aversions: effect of
naloxone at 24 hours postmorphine.
AB - The aversive properties of naloxone-precipitated withdrawal from acutely
administered morphine were assessed using the place-conditioning paradigm. The
conditioned place aversion produced by naloxone (0.5-1.0 mg/kg, s.c.) after two
conditioning trials was enhanced by pretreatment with morphine (20 mg/kg, s.c.)
24 h prior to the conditioning trial. Naloxone precipitated withdrawal from
acutely administered morphine produces an aversive motivational state that
becomes associated with place cues.
PMID- 9768569
TI - Nicotine-dizocilpine interactions and working and reference memory performance of
rats in the radial-arm maze.
AB - Both nicotinic cholinergic and NMDA glutaminergic systems are important for
memory function. Nicotine has been found repeatedly to significantly improve
working memory performance in the radial-arm maze. The NMDA antagonist
dizocilpine has been found to impair working memory performance. There is
neuropharmacological evidence that these two systems are functionally related.
Nicotine is potent at releasing many transmitters including glutamate. The
current study was conducted to examine the interaction of nicotinic and NMDA
systems with regard to working and reference memory. Rats were trained on a
working/reference procedure on a 16-arm radial maze. After acquisition, they were
administered nicotine (0, 0.2, and 0.4 mg/kg) and dizocilpine (0, 100, and 200
microg/kg) alone or in combination in a repeated measures, counterbalanced
design. As seen previously, nicotine at a dose of 0.2 mg/kg caused a significant
improvement in working but not reference memory performance in the radial-arm
maze. The 200 microg/kg dose of dizocilpine made the rats nonresponsive on the
maze so that choice accuracy could not be assessed. The 100 microg/kg dose of
dizocilpine caused significant impairments in both working and reference memory.
The 0.4 mg/kg dose of nicotine significantly attenuated the dizocilpine-induced
deficit in both working and reference memory. NMDA blockade impairs working and
reference memory and blocks the expression of the working memory improvement
caused by 0.2 mg/kg of nicotine. However, a higher dose of 0.4 mg/kg of nicotine
is effective at attenuating the dizocilpine-induced deficit, even though this
dose alone is not effective in improving performance. A second study examined the
effects of a lower dose range of dizocilpine. Comensurately smaller memory
impairments were seen with lower doses of dizocilpine down to 12.5 microg/kg,
which did not produce any significant effects on memory performance or response
latency. Nicotine had a more modest effect in attenuating the smaller deficits
caused by these lower doses of dizocilpine. These studies provide evidence for
important interactions between nicotinic and NMDA systems with regard to memory
function.
PMID- 9768570
TI - Future directions for allergen immunotherapy.
AB - Over the last 30 years several approaches to modify immunotherapy have been
tested, including allergoids, alum precipitation, and most recently peptides.
However, none of these have replaced the traditional regimens. Over the same
period our scientific understanding of allergic disease has been transformed.
Today it is possible to identify and monitor changes occurring during treatment
and to target many different aspects of the immune system. Recombinant technology
provides a powerful technique both for sequencing proteins and producing
allergens in commercial quantities. The recombinant proteins can be modified by
site-directed mutagenesis so as to decrease their reactivity with IgE antibodies
while maintaining reactivity with T cells. Knowledge of the tertiary structure of
allergens will make it simpler to identify and change surface epitopes. A
completely different approach is to use plasmids to introduce the genes for an
allergen. The strength of this technique is that the plasmid can be designed to
control expression and also to influence the cytokine profile of the response or
the isotype of antibodies produced. Finally, different adjuvants can be used with
proteins to alter the response. These include IL-12, immunostimulatory sequences
of DNA, and bacterial proteins such as those used in HibVax. It is now possible
to identify the cells that control the immune response to allergens and to design
treatments that will either downregulate or change the response of T cells. The
challenge is to transform this information into an effective treatment for
allergic disease.
PMID- 9768571
TI - Biologic activities of IL-1 and its role in human disease.
AB - The role of the polypeptide proinflammatory cytokine IL-1 family represents a
group of proteins that have contrasting and synergistic biologic responses. IL
1alpha and beta and their precursor forms are heavily involved in the enhancement
of inflammation and host defense. Within this family of gene products, there is
also a naturally occurring receptor antagonist, IL-1ra, as well as a family of
receptor proteins that have differential signaling functions and activities. The
study of these proteins in human disease, including allergic disease and type 1
hypersensitivity responses, has led to a better understanding of the underlying
general inflammation associated with these syndromes and has provided
opportunities to look at new forms of intervention in allergic disease and
asthma.
PMID- 9768572
TI - Diagnostic skin testing for natural rubber latex allergy.
PMID- 9768573
TI - Osteoporosis in the corticosteroid-treated patient with asthma.
AB - Osteoporosis affects 40% of white women older than 45 years of age and 15% of
white men older than 50 years of age, resulting in approximately 1.5 million
annual fractures in the United States. Systemic corticosteroid therapy increases
the probability of osteoporosis, even with alternate-day dosing and with dosages
sufficiently low so as not to affect the hypothalamic-pituitary-adrenal axis.
Inhaled corticosteroid therapy may affect bone density if high-dose therapy is
given to select individuals. The potential of increasing osteoporosis with
inhaled corticosteroid asthma therapy is a concern because of the availability of
more potent inhaled corticosteroid agents and recommendations that inhaled
corticosteroid therapy be initiated earlier in the course of asthma. This article
provides suggestions, on the basis of the medical literature and consensus of the
authors when specific information was not available, for assessing and treating
osteoporosis in subjects with asthma. Suggested risk categories are "low risk"
(inhaled corticosteroid dosage of < or =800 microg of heclomethasone dipropionate
[BDP]/day in adults or < or =400 microg BDP or equivalent in children), "moderate
risk" (inhaled BDP >800 microg/day in adults or >400 microg/day in children), and
"high risk" (systemic corticosteroid therapy 4 times a year or daily or alternate
day systemic corticosteroid therapy). Dosage of nasal corticosteroid probably
should be added to the orally inhaled corticosteroid for total burden of inhaled
corticosteroid. Potential treatment strategies based on risk factors and bone
density if indicated are offered to assist physicians treating patients with
asthma.
PMID- 9768574
TI - Comparison of 3 different doses of budesonide and placebo on the early asthmatic
response to inhaled allergen.
AB - BACKGROUND: A simple laboratory method to evaluate relative potency of inhaled
corticosteroids in asthma would be valuable. Single-dose studies with the
allergen-induced late asthmatic response have failed to show a useful dose
response relationship. Treatment for several days with inhaled corticosteroids
will also inhibit the allergen-induced early asthmatic response. METHODS: Twelve
atopic asthmatic subjects were studied during a season when no medications were
required except ipratropium bromide as needed. These subjects had positive
allergen and methacholine inhalation tests and FEV1 greater than 70% of predicted
value. A double-blind, randomized, cross-over study compared placebo and
budesonide 100, 200, and 400 microg administered by means of Turbuhaler twice
daily for 7 days with 6-day washout periods. Methacholine PC20 was measured
before and after 6 days of treatment, and allergen PC15 was measured after 7 days
of treatment. RESULTS: The allergen PC15 (n = 11) was significantly larger (P =
.0001) for all doses of budesonide compared with placebo, but there was no
significant difference between the 3 doses of budesonide, and no dose response
was demonstrated. The methacholine PC20 was significantly larger after all
budesonide treatments compared with placebo (P = .024), but there was no
difference between the 3 doses. There was a progressive increase in the allergen
PC15 chronologically (sequence effect) that was not explained by improvement in
FEV1 or airway responsiveness; sequence effects were not seen for FEV1 or for
pretreatment or posttreatment methacholine PC20. Statistical adjustment for
sequence effect did not alter allergen PC15 statistics. CONCLUSION: A 7-day
course of budesonide administered by means of Turbuhaler at 200, 400, or 800
microg per day provided marked and significant inhibition of the allergen-induced
early asthmatic response compared with placebo. There was, however, no difference
between the 3 doses. Therefore this method with these doses is not useful for
providing assessment of relative potency.
PMID- 9768575
TI - Differential regulation of allergen-specific T(H2)- but not T(H1)-type responses
by alveolar macrophages in atopic asthma.
AB - BACKGROUND AND OBJECTIVE: Previous studies have suggested that quantitative
differences in TH2-type cytokine responses in the airways are of particular
importance in the pathogenesis of asthma. In this study we investigated whether
alveolar macrophages (AMs) and peripheral blood monocytes (PMNs) are able to
significantly influence the profiles of allergen-induced TH1 (IFN-gamma) and TH2
(IL-4 and IL-5) cytokine production by CD4+ T cells in atopic asthmatic subjects
versus atopic nonasthmatic subjects and nonatopic normal subjects. METHODS:
Peripheral blood CD4+ T cells were cultured alone or cocultured with either PMNs
or AMs with allergen stimulation in the 3 groups. RESULTS: Although allergen
stimulation did not change TH1 or TH2 cytokine responses in cultures of CD4+ T
cells alone, the addition of PMNs to the cultures induced a significant increase
in production of IL-4, IL-5, and IFN-gamma (P < .01 or P < .001) in atopic
asthmatic subjects and atopic nonasthmatic subjects. However, PMNs induced a
significant increase for IFN-gamma (P < .05) only in normal subjects. AMs from
atopic asthmatic subjects significantly enhanced production of all 3 cytokines (P
< .01 or P < .001), whereas the AMs from atopic nonasthmatic subjects
significantly increased only production of IL-4 (P < .01) and IFN-gamma (P < .05)
but not IL-5. Furthermore, IL-4 (P = .066) and IL-5 (P < .01) production in
allergen-stimulated AM-CD4+ cell cocultures was higher in atopic asthmatic
subjects but significantly lower in atopic nonasthmatic subjects (P < .05) as
compared with the PMN-cocultures. For IFN-gamma, no difference was found between
the AM and PMN cocultures in either atopic group. Allergen-stimulated IL-5
production in coculture with both AMs and PMNs inversely correlated with both
baseline FEV1 percent predicted and PD20 methacholine in atopic asthmatic
subjects (P < .05, P < .01, or P < .001). CONCLUSION: These data suggest that AMs
from atopic asthmatic subjects but not atopic nonasthmatic subjects, play a
significant role in airway pathogenic immunity through enhancing TH2-type
cytokine production.
PMID- 9768576
TI - Expression of epithelial markers in nocturnal asthma.
AB - BACKGROUND: Although the airway epithelium participates in inflammation and
repair, the circadian expression of epithelial cell markers involved in these
processes has not been investigated. OBJECTIVE: We sought to determine whether
expression of CD51 (vitronectin and fibronectin receptor), CD54 (intercellular
adhesion molecule-1), HLA-DR (activation marker), CD29 (beta1 integrin), CD49b
(collagen receptor), and CD11b (complement receptor) exhibit a circadian rhythm
in asthma. METHODS: Eleven patients with nocturnal asthma (NA), 9 subjects with
nonnocturnal asthma (NNA), and 10 control subjects underwent bronchoscopy at 4 PM
and 4 AM in a random order 1 week apart, with brushing of the proximal and distal
airways. The percentage of cells staining for a particular marker was determined.
RESULTS: At 4 PM, HLA-DR in the proximal airways and CD54 in the distal airways
was significantly greater in control subjects as compared with asthmatic subjects
(HLA-DR, control subjects: 10.0% [range, 5.0% to 21.0%]; NNA: 8.0% [range, 4.0%
to 14.5%] NA: 3.5% [range, 2.0% to 6.0%], P = .01; CD54, control subjects: 17.0%
[range, 8.0% to 25.0%], NNA: 8.0% [range, 5.3% to 11.5%], NA: 7.0% [range, 4.0%
to 15.0%], P = .O;). At 4 AM, CD51 in the distal airways was significantly
greater in patients with NA as compared with patients with NNA and control
subjects (control subjects, 23.0% [range, 13.8% to 30.5%]; NNA, 32.0% [range,
13.0% to 35.0%]; NA, 40.0% [range, 23.0% to 50.0%], P = .05). Expression of CD51
in the distal airways correlated with the degree of airway obstruction (r =
0.57, P = .001). Control subjects exhibited significant circadian variation in
the expression of HLA-DR in the proximal airways and CD54 in the distal airways.
CONCLUSION: The increased CD51 at night in patients with NA may be related to
increased airway inflammation and repair processes in response to injury. The
circadian changes in CD54 and HLA-DR in control subjects require further study to
determine their significance. (J Allergy Clin
PMID- 9768577
TI - Association between Der p 1 concentration and peak expiratory flow rate in
children with wheeze: a longitudinal analysis.
AB - BACKGROUND: House dust mite (HDM) allergen exposure has been well documented as
an environmental cause of airway hyperresponsiveness (AHR) and asthma symptoms.
The relationship between asthma morbidity and exposure to low concentrations of
HDM allergen suggests that there may be no safe exposure threshold to HDM
allergen. OBJECTIVE: We aimed to investigate the associations between Der p 1 in
bedding and lung function in 30 children with a history of wheezing in a
longitudinal study. METHODS: After a cross-sectional study of school children,
which included histamine challenge for AHR and skin testing for dust mite atopy,
we made repeated measurements of HDM allergens in children with a history of
wheeze over a 12-month period. These children also kept a daily asthma diary in
which they recorded their peak expiratory flow rates (PEFRs). We used a repeated
measures model to determine the association between PEFR and HDM allergen
concentration. RESULTS: There was a significant association between PEFRs and HDM
allergen concentration (beta-coefficient = -14.17, P = .0024) in children with
HDM atopy. An association was not found in children without HDM atopy.
CONCLUSIONS: These findings support the hypothesis that HDM allergens have an
adverse effect on the lung function of children with wheeze and highlight the
importance of maintaining low dust mite allergen levels throughout the year in
the home environment of children sensitized to HDMs.
PMID- 9768578
TI - Evaluation and treatment of allergic fungal sinusitis. I. Demographics and
diagnosis.
AB - BACKGROUND: Few cases of allergic fungal sinusitis have been systematically
evaluated to conclusively confirm working clinical, histopathologic, and
serologic diagnostic criteria. OBJECTIVES: The objective of this study was to
describe 67 consecutive cases of allergic fungal sinusitis, the largest number of
cases yet published. METHODS: Cases from 1 practice over 8 years were evaluated
with a consistent protocol, including skin testing, serum chemistries and
serologies, and surgical specimen analysis. RESULTS: All patients were atopic
(100 %) and had nasal polyposis (100%). They tended to be young (33.3+/-13.1
years, mean +/-SEM), immunocompetent (92 %; remaining 8 % with low quantitative
immunoglobulin but normal function), have slight female preponderance (58%), have
a history of hypertrophic rhinosinusitis (100%), report nasal cast production
(75%), and have developed their disease in the southwestern United States.
Bipolaris spicifera was the most prevalent fungus involved (67%). Total serum IgE
(mean 668 IU/mL) and fungal-specific IgG were generally elevated, whereas fungal
specific precipitins and specific IgE were generally negative despite positive
fungal-specific immediate hypersensitivity skin tests. CONCLUSIONS: Patients with
allergic fungal sinusitis tend to have elevated total serum IgE and fungal
specific IgG at diagnosis but not fungal-specific IgE or precipitins.
Histopathologic criteria for allergic fungal sinusitis diagnosis are discussed.
The southwestern United States appears to be a "hot spot" for the disease,
particularly caused by B spicifera.
PMID- 9768579
TI - Evaluation and treatment of allergic fungal sinusitis. II. Treatment and follow
up.
AB - BACKGROUND: Previous allergic fungal sinusitis case reports have speculated that
oral corticosteroids might reduce the severity of disease and possibly forestall
the high rate of recurrent sinus surgery. OBJECTIVES: Our objective was to
comprehensively review 67 consecutive cases of allergic fungal sinusitis for
their response to treatment and the utility of monitoring patient serologies
during clinical follow-up. METHODS: Allergic fungal sinusitis cases from a
private practice were evaluated and treated with consistent diagnostic criteria
and treatment paradigms. An 8-year retrospective review of serologic parameters
and clinical response to treatment with or without oral corticosteroids is
described. RESULTS: The total serum IgE was found to correlate with the clinical
rhinosinusitis severity (P = .0002). The fungal-specific IgG also correlated with
clinical rhinosinusitis severity but less rigorously (P = .004). An increase of
10% or more in total serum IgE during follow-up was found to have significant
predictive value for recurrent surgical intervention, with a sensitivity of 79%,
specificity of 77%, positive predictive value of 48%, and negative predictive
value of 93% (P < .0001). With the use of a modified corticosteroid treatment
regimen adapted from allergic bronchopulmonary aspergillosis, as little as 2
months of oral corticosteroids after surgery provided significant clinical
improvement for up to 12 months (P < .0001), although patients taking 12 months
of treatment fared the best clinically (P = .03). By survival analysis, oral
corticosteroids prolonged the time between subsequent sinus surgeries (P = .01)
in this highly recurrent disease. No significant side effects of oral
corticosteroids were observed during treatment with this dosing regimen.
CONCLUSIONS: Postoperative oral corticosteroids appear to be an effective
treatment option for allergic fungal sinusitis, and monitoring of total serum IgE
can be helpful in the clinical follow-up of these patients.
PMID- 9768580
TI - Sinusitis in the common cold.
AB - BACKGROUND: Acute community-acquired sinusitis is considered a bacterial
complication of the common cold. Radiologic abnormalities in sinuses occur,
however, in most patients with upper respiratory virus infections. OBJECTIVE:
Assessment of the occurrence, clinical profile, laboratory findings, and outcome
of radiologically confirmed sinusitis was carried out as part of a common cold
study in young adults. METHODS: Clinical examinations and radiography of the
paranasal sinuses were carried out on days 1, 7, and 21 in 197 patients with the
common cold. The symptoms were recorded on diary cards on days 1 to 20. Ten
viruses and 5 bacteria were studied as etiologic agents of common cold as
reported earlier. Serum C reactive protein concentrations, erythrocyte
sedimentation rates, and total white blood cell counts with differentials were
determined in 40 randomized subjects on day 7. The effect of 6 days of intranasal
fluticasone propionate treatment of the common cold in the prevention of
sinusitis was analyzed. RESULTS: On day 7, 39% of patients with the common cold
in the placebo group (n = 98) had sinusitis, which we would prefer to call viral
sinusitis. The symptoms of patients with sinusitis and those without it were not
clinically distinguishable. Viral infection was detected in 81.6% of patients
with sinusitis. No significantly increased levels of antibodies to bacteria were
detected. Serum C reactive protein concentrations, erythrocyte sedimentation
rates, and white blood cell counts were low in patients with sinusitis. All
patients made a clinical recovery within 21 days without antibiotic treatment.
Fluticasone propionate treatment tended to prevent paranasal sinusitis,
especially in rhinovirus-positive subjects. CONCLUSION: Viral sinusitis
frequently occurs in the early days of the common cold, but it is a self-limited
illness. The sinuses should not be imaged in patients with the common cold if the
signs and symptoms of illness gradually become less severe and no specific signs
suggestive of bacterial sinusitis occur.
PMID- 9768581
TI - Validation of the Doser, a new device for monitoring metered-dose inhaler use.
AB - BACKGROUND: Electronic monitoring of medication use has proved valuable in both
clinical and research settings. The Doser, a new and inexpensive commercially
available device for monitoring metered-dose inhaler (MDI) use, displays 3
measures of daily use of an attached MDI: (1) the daily total of actuations, (2)
the number of doses remaining in the MDI, and (3) the number of actuations on
each of the preceding 30 days for later recall. OBJECTIVE: We sought to validate
the accuracy of the Doser with several commonly prescribed MDIs. METHODS: In the
laboratory, clinic personnel actuated an MDI with an attached Doser several times
in succession on 3 consecutive days and recorded each of the 3 measures of MDI
use (study 1). In study 2 clinic personnel carried an MDI and attached Doser with
them for 4 weeks, actuating the MDI according to a prescribed protocol each
morning and evening and again recording each of the 3 measures of daily use. In
addition, during 2 weeks of study 2, a thermistor-based Nebulizer Chronolog was
attached to the MDI to electronically record the date and time of each actuation.
In study 3 clinic patients had both a Doser and Nebulizer Chronolog attached to
their routinely used inhalers for 2 weeks and a Doser alone during a separate 2
week period. RESULTS: In study 1 agreement was 99% to 100% among the 3 Doser
measures, and each measure agreed with actual use by self-report 97% of the time.
In study 2 agreement among the 3 Doser measures of use ranged from 98% to 99%.
Agreement between each of the 3 Doser measures and the Nebulizer Chronolog ranged
from 90% to 93%. Agreement between each of the 3 Doser measures and actual use
ranged from 96% to 97%, and the Nebulizer Chronolog agreed with actual use 93% of
the time. In study 3 Doser and Nebulizer Chronolog agreement with patient self
report were 85% and 80%, respectively. Agreement between the Doser and Nebulizer
Chronolog was 76%. Several failures of the thermistor-based Nebulizer Chronolog
occurred, and occasional mechanical problems occurred with the Doser, primarily
on particular types of MDI canisters. CONCLUSION: The Doser provides an accurate
measure of MDI use with most commonly prescribed medications and may be useful
for monitoring MDI use by investigators, clinicians, and patients.
PMID- 9768582
TI - Ascaris-specific IgE and allergic sensitization in a cohort of school children in
the former East Germany.
AB - BACKGROUND: Helminthic infections induce an IL-4-dependent polyclonal stimulation
of IgE synthetization. It is still unclear, however, what role helminths play in
allergic sensitization. OBJECTIVE: We sought to determine the relationship
between Ascaris-specific IgE and allergic sensitization in a nontropical country.
METHODS: In 2 consecutive cross-sectional surveys in 1992-1993 and 1995-1996,
data from school entrants (age range, 5 to 7 years), third graders (age range, 8
to 10 years), and sixth graders (age range, 11 to 14 years) were collected. The 2
younger groups were reexamined in the second survey. Data for about 2300
children, including a cohort of 700 subjects, were analyzed. Ascaris IgE and
total and specific IgE to inhalant allergens were measured, and skin prick tests
were performed. Information about asthma and allergic rhinitis was collected by a
questionnaire. RESULTS: Children who were Ascaris-IgE seropositive (>0.35 IU/mL)
in both surveys had 10-fold higher levels of total IgE (451 IU/mL vs 45 IU/mL, P
< .001) and higher prevalence rates of allergen-specific IgE seropositivity
(56.3% vs 26.6%, P < .001). They also had a higher prevalence of allergic
rhinitis (12.6% vs 3.7%, P < .001) and asthma (5.7% vs 1.6%, P < .05). In
subjects who were Ascaris-seronegative in the first survey but seropositive in
the second survey, total and specific IgE increased markedly. Sensitization to
Dermatophagoides pteronyssinus increased nearly 3-fold in this group. In
contrast, in children who became Ascaris-seronegative, total and specific IgE
decreased. CONCLUSIONS: Contact with low doses of helminthic antigen is
associated with an increase of total and specific IgE production. Helminthic
infections in East German children are not the cause for a low prevalence of
allergies in the former East Germany.
PMID- 9768583
TI - Intravenous immunoglobulin inhibits IgE production in human B lymphocytes.
AB - BACKGROUND: Intravenous immunoglobulin (IVIG) is commonly used as both an immune
enhancing and immune-modulating agent. Treatment with high doses of IVIG
diminishes IgE secretion in patients with severe steroid-dependent asthma.
OBJECTIVE: We studied the action of IVIG on IgE production in highly purified B
lymphocytes stimulated without additional T cells to determine the action of IVIG
on B lymphocytes. METHODS: Human B cells were purified from tonsils, and T
lymphocytes were removed by E-rosetting. B cells were cultured with IL-4 (400
U/mL) and anti-CD40 antibodies (1 microg/mL?, with or without additional IVIG.
Cell proliferation was determined by 3[H]-thymidine uptake, and supernatant IgE
was determined by ELISA. Cell cycle analysis was performed by flow cytometry, and
IgE transcripts were measured by in situ hybridization. RESULTS: IVIG (5 mg/mL)
decreased B-cell proliferation in IL4/anti-CD40-stimulated B cells by an average
of 74% (+/-6%). Addition of IVIG up to 48 hours after initiation of cell culture
led to significant diminution of cell proliferation at 96 to 120 hours. This
effect was dose dependent, with 10 mg/mL being the most effective and doses under
0.1 mg/mL having minimal effect. IVIG diminished the number of stimulated cells
progressing in the cell cycle by 30%, and there was no difference in cell
viability between IVIG-treated and IVIG-untreated cells. The production of IgE in
culture by anti-CD40/IL4-stimulated B lymphocytes was curtailed by greater than
80% after addition of 5 mg/mL IVIG. This was associated with a decrease in IgE
(epsilon) transcripts in IVIG-treated cultures. CONCLUSION: These data indicate
that diminution of IgE production in anti-CD40/IL-4-stimulated B cells by IVIG is
due to inhibition of early events related to proliferation and progression in the
cell cycle.
PMID- 9768584
TI - Reduced prevalence of allergic disease in patients with multiple sclerosis is
associated with enhanced IL-12 production.
AB - BACKGROUND: We previously showed that the prevalence of allergic disease is
decreased in patients with multiple sclerosis (MS); however, the mechanisms that
explain this finding have not previously been defined. OBJECTIVES: We have
demonstrated that protection of patients with MS from allergic disease may be
caused by the production in monocytes from these patients of elevated quantities
of IL-12 compared with that observed in monocytes from individuals with
allergies. METHODS: Purified monocytes from peripheral blood of subjects with or
without allergies and from individuals with MS were directly stimulated with
Staphylococcus aureus Cowan strain I in the absence of T cells. IL-12 was
quantitated by a sensitive reverse transcription, competitive PCR. RESULTS: IL-12
production was 5-fold greater in monocytes from patients with MS (n = 11) than
that from individuals with allergies (n = 10) (for subjects with MS, 1.90+/-0.18
vs 1.24+/-0.19 log10 fmol/microL for individuals with allergies) (P = .02).
Although the production of IL-12 in monocytes from patients with MS was slightly
higher than that from subjects without allergies, this difference was not
statistically significant. CONCLUSIONS: IL-12 production in individuals with MS
is much greater than in individuals with allergies. Because IL-12 induces TH1
cytokine synthesis and reduces the production of TH2 cytokines, which amplify and
prolong allergic inflammation, these studies suggest that enhanced IL-12
production may protect individuals with MS from the development of allergy but
may predispose such individuals toward autoimmune inflammation in the central
nervous system.
PMID- 9768585
TI - Genetic regulation of Dermatophagoides pteronyssinus-specific IgE responsiveness:
a genome-wide multipoint linkage analysis in families recruited through 2
asthmatic sibs. Collaborative Study on the Genetics of Asthma (CSGA).
AB - BACKGROUND: Dermatophagoides pteronyssinus (Der p) is one of the most frequently
implicated allergens in atopic diseases. Although HLA could play an important
role in the development of the IgE response to the Der p allergens, genetic
regulation by non-HLA genes influences certain HLA-associated IgE responses to
complex allergens. OBJECTIVE: To clarify genetic control for the expression of
Der p-specific IgE responsiveness, we conducted a genome-wide search for genes
influencing Der p-specific IgE antibody levels by using 45 Caucasian and 53
African American families ascertained as part of the Collaborative Study on the
Genetics of Asthma (CSGA). METHODS: Specific IgE antibody levels to the Der p
crude allergen and to the purified allergens Der p 1 and Der p 2 were measured.
Multipoint, nonparametric linkage analysis of 370 polymorphic markers was
performed with the GENEHUNTER program. RESULTS: The best evidence of genes
controlling specific IgE response to Der p was obtained in 2 novel regions:
chromosomes 2q21-q23 (P = .0033 for Caucasian subjects) and 8p23-p21 (P = .0011
for African American subjects). Three regions previously proposed as candidate
regions for atopy, total IgE, or asthma also showed evidence for linkage to Der p
specific IgE responsiveness: 6p21 (P = .0064) and 13q32-q34 (P = 0.0064) in
Caucasian subjects and 5q23-q33 (P = 0.0071) in African American subjects.
CONCLUSIONS: No single locus generated overwhelming evidence for linkage in terms
of established criteria and guidelines for a genome-wide screening, which
supports previous assertions of a heterogeneous etiology for Der p-specific IgE
responsiveness. Two novel regions, 2q21-q23 and 8p23-p21, that were identified in
this study merit additional study.
PMID- 9768586
TI - Linkage analysis of Dermatophagoides pteronyssinus-specific IgE responsiveness
with polymorphic markers on chromosome 6p21 (HLA-D region) in Caucasian families
by the transmission/disequilibrium test. Collaborative Study on the Genetics of
Asthma (CSGA).
AB - BACKGROUND: Recently, we have obtained evidence for linkage between Der p 1
specific IgE antibodies and markers on chromosome 6p21 (HLA-D region) in a genome
wide screening in Caucasian families recruited as a part of the Collaborative
Study on the Genetics of Asthma (CSGA). OBJECTIVE: Specific IgE antibodies toward
different Dermatophagoides pteronyssinus (Der p) polypeptides were detected by
immunoblotting analysis, and the transmission/disequilibrium test (TDT) was
performed between specific IgE responsiveness toward each different Der p
polypeptide and markers on chromosome 6p21 to better clarify the genetic
contribution of HLA-D genes. METHODS: We studied 299 individuals in 45 Caucasian
families participating in the CSGA. Serum samples from 137 individuals that
showed elevated specific IgE antibodies toward the Der p crude allergen (> -0.5
log IU/mL) by ACCESS immunoassay were subjected to immunoblotting analysis. TDT
was conducted between the presence of specific IgE antibodies toward each of 12
different Der p polypeptides and 4 polymorphic markers on chromosome 6p21.
RESULTS: The 196-bp allele of D6S1281 and the 104-bp allele of DQCAR showed
significant excess transmission to specific IgE responders toward a particular
Der p polypeptide (120 kd, 55 kd, 45 kd, or 37 kd). In contrast, the 200-bp
allele of D6S1281 and the 204-bp allele of D6S291 showed significantly decreased
transmission to specific IgE responders toward a particular Der p polypeptide
(120 kd, 90 kd, 52 kd, or 45 kd). Deviation from the expected 50% transmission in
heterozygous parents was statistically significant after correcting for multiple
comparisons. CONCLUSION: This study supported our previous findings that genes on
chromosome 6p21 (HLA-D region) may influence the expression of Der p-specific IgE
responsiveness in this Caucasian population. Our results, however, reveal the
complexity of genetic regulations of Der p-specific IgE responsiveness by HLA-D
genes, suggesting the strong influence of non-HLA loci and perhaps environmental
factors for the development of Der p-specific IgE responsiveness.
PMID- 9768587
TI - Genetic influences of chromosomes 5q31-q33 and 11q13 on specific IgE
responsiveness to common inhaled allergens among African American families.
Collaborative Study on the Genetics of Asthma (CSGA).
AB - BACKGROUND: We have recently conducted a genome-wide screening for genes
influencing Dermatophagoides pteronyssinus-specific IgE responsiveness as a part
of the Collaborative Study on the Genetics of Asthma (CSGA), which showed
evidence for linkage in some regions, including chromosomes 5131-q33 and 11q13 in
African American families. OBJECTIVES: To clarify relative contributions of these
regions to atopy in the same African American population, we have conducted
further genetic linkage studies of specific IgE responses toward common inhaled
allergens. METHODS: We studied 328 individuals in 58 African American families
participating in the CSGA. Specific IgE responses toward Dermatophagoides
farinae, cat, dog, American cockroach, rye grass, and Bermuda grass, as measured
by skin tests, were used for multipoint linkage analysis with polymorphic markers
on chromosomes 5q31-q33 and 11q13. RESULTS: Specific IgE response toward American
cockroach showed evidence for linkage to chromosomes 5q31-q33 (P = .0050) and
11q13 (P = .017). Specific IgE response toward dog showed evidence for linkage
with chromosome 5q31-q33 (P = .0043). Evidence for linkage with chromosome 11q13
was obtained for specific IgE responses toward Dermatophagoides farinae (P =
.012), cat (P = .035), and Bermuda grass (P = .017). The presence of a positive
ST response for at least 1 of 30 common allergens showed evidence for linkage to
chromosomes 5q31-q33 (P = .017) and 11q13 (P = .00058). CONCLUSIONS: These data
support that genes on both chromosomes 5q31-q33 and 11q13 confer susceptibility
to upregulated IgE-mediated immune responses in this African American population.
The putative genes on chromosomes 5q31-q33 and 11q13, however, showed contrasting
effects on atopy, which may result from strong gene-environmental interactions.
PMID- 9768588
TI - Nerve growth factor is preformed in and activates human peripheral blood
eosinophils.
AB - BACKGROUND: Recent studies have shown that nerve growth factor (NGF) is produced
by and can act on several immune-inflammatory cells. OBJECTIVES: The objective of
this study was to study the effects of NGF on human peripheral blood eosinophils
and assess whether these cells produce and store NGF. METHODS: Eosinophils were
purified by negative immunoselection (magnetic cell sorting systems, purity 98%
to 100%) from 13 subjects (9 to 26 years old) with mild blood eosinophilia,
mainly of allergic origin. Eosinophils were incubated with NGF (50 to 1000
ng/mL), and supernatants were collected for measurement of eosinophil peroxidase
(EPO, 20 minutes, colorimetric enzymatic assay) and IL-6 (12 hours, ELISA).
Eosinophil viability was evaluated by Trypan blue test (days 2, 3, and 4). NGF
content in freshly isolated eosinophils, after ultrasound disruption, was
determined with a 2-site immunoenzymatic assay. The presence of mRNA for NGF was
evaluated by reverse transcription PCR. RESULTS: NGF caused EPO release (highly
significant at 1000 ng/mL NGF). IL-6 release from eosinophils was not higher than
IL-6 spontaneously released into culture medium alone. NGF did not significantly
affect the number of viable eosinophils. NGF was found in the eosinophil
sonicates (1.5 to 17.8 pg/mL per 106 cells). Similarly, mRNA for NGF was detected
by reverse transcription PCR in the freshly isolated eosinophils. CONCLUSIONS:
NGF activates human peripheral blood eosinophils from subjects with mild
eosinophilia to selectively release inflammatory mediators. Eosinophils store and
produce NGF. Therefore the capability of NGF to induce a secretory response and
its production and storage by circulating human eosinophils suggest a possible
role for NGF in conditions associated with eosinophilia, including allergic
disease.
PMID- 9768589
TI - Adhesion molecule expression on skin endothelia in atopic dermatitis: effects of
TNF-alpha and IL-4.
AB - BACKGROUND: Atopic dermatitis (AD) is characterized by skin infiltrates of
leukocytes, such as lymphocytes and eosinophils. OBJECTIVE: To describe the
mechanisms determining this inflammatory process, we have analyzed expression of
adhesion molecules and their regulation on skin endothelial cells (ECs). METHODS:
Expression of adhesion molecules on ECs was analyzed by immunohistochemistry by
using Ulex europaeus agglutin 1 as a pan-endothelial marker. RESULTS: Vascular
cell adhesion molecule-1 (VCAM-1), E-selectin, and P-selectin were not found in
skin of nonatopic individuals, whereas expression of these surface molecules was
observed in nonlesional skin of patients with AD and was even more pronounced in
lesional skin or after epicutaneous application of aeroallergen. Induction of
adhesion molecule expression was examined on both macrovascular ECs from human
umbilical cord vein (HUVECs) and human microvascular ECs (HMEC-1) from skin. TNF
alpha very potently upregulated adhesion molecule expression in vitro on both EC
cell types. To verify the in vivo relevance of TNF-alpha, we performed TNF-alpha
staining in the skin. TNF-alpha was observed in the dermis of nonatopic skin,
both in chymase-containing mast cells and CD68+ macrophages. The increase in the
number of TNF-alpha-containing cells was concomitant with the increase in
adhesion molecule expression in the skin of patients with AD. IL-4 is supposed to
be important in atopic diseases because of its IgE- and VCAM-1-inducing
properties. However, IL-4 addition failed to induce VCAM-1 expression on HMEC-1,
although in the same set of experiments, a clear induction of VCAM-1 expression
by IL-4 on HUVECs was demonstrated. Flow cytometry revealed the absence of 11-4
receptor alpha-chains on HMEC-1 and their presence on HUVECs.
Immunohistochemistry examination on skin sections showed no binding of the IL-4R
alpha-chain antibodies to ECs. CONCLUSION: We conclude that adhesion molecule
expression is increased in the skin of patients with AD. Most probably, this
increased expression is not a (direct) effect of IL-4 on skin endothelium, but
other cytokines, such as TNF-alpha, might be responsible for this increased
adhesion molecule expression. Continuous adhesion molecule expression may
facilitate T-cell extravasation in a nonantigen-specific manner, thus explaining
the presence of increased T-cell numbers in nonlesional skin of patients with AD.
PMID- 9768590
TI - The latex allergen Hev b 5 transcript is widely distributed after subcutaneous
injection in BALB/c mice of its DNA vaccine.
AB - BACKGROUND: DNA vaccines reduce IgE responses to selected allergens, but severe
reactions to the expressed antigen may limit the usefulness of the technique in
allergen immunotherapy. OBJECTIVE: We sought to determine the extent of spread of
an injected DNA vaccine in mice. METHODS: We placed the gene encoding the potent
Hevea latex allergen Hev b 5 in a mammalian expression vector and injected this
DNA vaccine subcutaneously into BALB/c mice. At several times after injection,
the presence of Hev b 5 transcript was determined in multiple tissues by RT-PCR.
The identity of the amplification product was confirmed by Southern hybridization
and restriction analyses. RESULTS: Hev b 5 RNA appeared at the injection site and
in the lymph nodes, spleen, and lungs within 1 day after injection and persisted
for at least 14 days. Hev b 5 RNA was also identified in the blood and tongue 14
days after injection. Antibody and cell-mediated responses to Hev b 5 were also
noted in the immunized animals at later time points. As expected, animals
injected with the identical plasmid containing the Hev b 5 DNA in the antisense
orientation mounted no immune response to Hev b 5. CONCLUSIONS: The rapid and
widespread appearance of the Hev b 5 transcript in the injected mice confirms
that DNA is translocated from the injection site, transcribed, and expressed in
immune and nonimmune tissues after injection. Controlling the extent and degree
of expression in specific target tissues may allow therapeutic DNA vaccination
with plasmids that encode potentially toxic allergens.
PMID- 9768591
TI - Identification of hevein (Hev b 6.02) in Hevea latex as a major cross-reacting
allergen with avocado fruit in patients with latex allergy.
AB - BACKGROUND: Recent studies demonstrated that allergy to natural rubber latex is
frequently associated with hypersensitivity to avocado fruit. The responsible
cross-sensitizing allergen has not been identified. OBJECTIVE: The purpose of
this study was to investigate the cross-reactivity of a latex major allergen,
hevein, with avocado proteins. METHODS: Serum samples from 118 health care
workers (HCWs) allergic to latex (HCW group) and 78 patients with spina bifida
(SB) allergic to latex (SB group) were included in this study. Anti-hevein and
anti-avocado IgE antibodies were measured by enzyme-linked allergosorbent assay.
Cross-reactivity of hevein to avocado proteins was assessed by inhibition of the
IgE binding in individual patients' sera containing IgE antibodies to both hevein
and avocado. RESULTS: The prevalence of seropositive IgE antibodies to avocado
was found to be strongly associated with the presence of hevein-specific IgE
antibodies in subjects of both groups (P < .001). Sixty-seven of 91 (73%)
subjects from the HCW group and all 19 subjects in the SB group with positive IgE
antibodies to hevein also had elevated IgE values to avocado. Competitive RAST
inhibition with 42 sera showed that IgE binding to avocado could be completely
inhibited in 27 (64%) sera by preincubation with hevein. By contrast, the degrees
of inhibition of IgE to hevein by avocado extract ranged from 0% to 36% (n = 16).
These results indicate that sensitization to avocado in most patients allergic to
latex is caused exclusively by IgE-binding epitopes present in hevein. Results of
immunoblots and immunoblot inhibition with 11 serum samples confirmed that a 30
kd protein in avocado was the major IgE-binding component; the IgE-binding
reactivity to this protein could be inhibited by hevein in all sera tested.
CONCLUSION: Hevein is the major cross-reacting allergen with avocado in subjects
with latex allergy.
PMID- 9768592
TI - Diagnosis of natural rubber latex allergy: multicenter latex skin testing
efficacy study. Multicenter Latex Skin Testing Study Task Force.
AB - BACKGROUND: No characterized diagnostic natural rubber latex skin testing
material is licensed for use in the United States. OBJECTIVE: We have conducted a
multicenter clinical skin testing study to document the safety and diagnostic
sensitivity and specificity of a candidate Hevea brasiliensis nonammoniated latex
(NAL) extract. These data are intended to support the licensing of this reagent
for the diagnosis of latex allergy in high-risk populations. METHODS: Three
hundred twenty-four subjects (304 adults and 20 children) were classified by
their clinical history as having latex allergy (LA group, 124 adults and 10
children) or having no latex allergy (NLA group, 180 adults and 10 children). All
subjects provided blood samples and then received sequential puncture skin tests
(PSTs) at 1, 100, or 1000 microg/mL protein with a bifurcated needle and NAL
(Greer Laboratories) from Malaysian Hevea brasiliensis (clone 600) sap. A 2-stage
glove provocation test was used to clarify latex allergy status of individuals
with positive history/negative PST result and negative history/positive PST
result mismatches. RESULTS: Twenty-four subjects (15%) originally designated as
having LA on the basis of their initial clinical history were reclassified to the
NLA group on the basis of a negative glove provocation test result. Of the 134
subjects with LA, 54 (40%) were highly sensitive to latex, with a positive PST
result at 1 microg/mL NAL. The Greer NAL reagent produced a positive PST rate
(sensitivity) of 95% and 99% in subjects with LA at 100 microg/mL and 1 mg/mL,
respectively. The negative PST rate (specificity) in 190 subjects with a negative
history with the NAL extract at 100 microg/mL and 1 mg/mL, was 100% and 96%,
respectively. Immediately after the PST, mild systemic reactions (mainly
pruritus) were recorded in 16.1 % of the adults in the LA group and 4.4% of the
adults in the NLA group. No reactions required treatment with epinephrine. Only
mild delayed reactions were observed in 9.6% (LA group) and 2.8% (NLA group) of
subjects 24 to 48 hours after PST. Mean wheal and erythema diameters measured in
the 10 children in the LA group with spina bifida at 100 microg/mL and 1 mg/mL
were similar to those observed in the adults in the LA group, suggesting that
children are not at increased risk for systemic reactions compared with adults.
CONCLUSIONS: A suggestive clinical history is necessary but not sufficient for a
definitive diagnosis of IgE-dependent latex allergy. These data support the
safety and diagnostic efficacy of the Greer NAL, skin test reagent at 100
micro/mL and 1 mg/mL for confirmatory PSTs.
PMID- 9768593
TI - Human mast cells produce IL-13 by high-affinity IgE receptor cross-linking:
enhanced IL-13 production by IL-4-primed human mast cells.
AB - BACKGROUND: Mast cells play a central role not only in the early phase of the
allergic reaction, but also participate in the late phase of the allergic
reaction through the allergen and IgE-dependent release of multifunctional
cytokines. OBJECTIVE: Using the recently established culture system for human
mast cells, we examined the expression of a variety of cytokines in cord blood
derived human cultured mast cells (HCMCs) in response to different stimuli.
METHODS: HCMCs were grown from cord blood mononuclear cells in the presence of
stem cell factor and IL-6 for 10 weeks. Cytokine mRNA expression in HCMCs by the
different stimuli was examined by RT-PCR. Then taking 2 important cytokines, IL
13 and IL4, that share several functional properties and play important roles in
allergic diseases, we examined protein as well as mRNA expression of both
cytokines in HCMCs. RESULTS: HCMCs did not express either IL-13 or IL-4
spontaneously. Stimulation with PMA + A23187 induced the expression of IL4
protein, as well as IL-13 protein, in their cytoplasm, although IL-4 secreted in
the supernatant was below detectable levels in contrast to a significant amount
of IL-13. Stimulation of HCMCs by cross-linking of the high-affinity IgE receptor
(Fc(epsilon)RI) induced the expression of IL-13 mRNA and protein, but not IL4.
Although we previously found that IL-4 upregulates Fc(epsilon)RI expression on
HCMCs, when HCMCs were first cultured in the presence of IL4 and then activated
through FC(epsilon)RI cross-linking, remarkable increase was found in IL-13
production. Furthermore, although IL-4 was still undetectable at protein level,
IL-4 mRNA expression was induced in the IL-4-primed HCMCs stimulating
Fc(epsilon)RI cross-linking. In addition, we examined the effects of these
cytokines on the surface molecule expression in HCMCs. Although IL4 remarkably
upregulated lymphocyte function-associated antigen-1, intercellular adhesion
molecule-1, and Fc(epsilon)RI expression and downregulated c-kit expression in
HCMCs, IL-13 did not. CONCLUSIONS: Our observation that HCMCs produce IL-13 on
cross-linking of Fc(epsilon)RI, which was enhanced by IL-4 priming, supports an
important role of mast cells in amplification of allergic reaction and further
suggests one of the mechanisms enhancing mast cell function in the
microenvironment.
PMID- 9768594
TI - Analysis of cytokine signaling in patients with extrinsic asthma and
hyperimmunoglobulin E.
AB - BACKGROUND: Recent data suggest that the regulation of class switching to IgE by
cytokines is mediated by STAT transcription factors. The induction of IgE by IL-4
and IL-13 occurs through the activation of the intracellular signal-transducing
protein Stat6, whereas the inhibition of IgE class switching by interferon-y (IFN
gamma) occurs through the activation of Statl. OBJECTIVE: We hypothesized that in
extrinsic asthma or in cases of markedly elevated IgE (ie, hyperimmunoglobulin E
[HIE]) increased levels of IgE may be associated with alterations in the cytokine
levels or the activation of Stat6. METHODS: PBMCs and sera from 8 patients with
extrinsic asthma (mean IgE, 285+/-100 IU/mL), 3 patients with HIE (mean IgE,
7050+/-1122 IU/mL), and 14 nonatopic control subjects (mean IgE, 112+/-28 IU/mL)
were analyzed. RESULTS: The mean IL-4 level detected by ELISA was much greater in
patients with HIE than control subjects (88.6+/-11.5 pg/mL vs 11.5+/-7.1 pg/mL, P
= .005), and increased IL-4 levels among patients with both asthma and HIE
correlated with the increased IgE levels. In contrast, IL-13 levels were not
elevated. Levels of Stat6 protein present in PBMCs did not differ in the patients
and control subjects. Examination of Stat6 DNA-binding activity demonstrated no
activation of IL-4 signaling in patients with either HIE or acute asthma.
Interestingly, evidence for the presence of B cells that have already switched to
IgE was seen in PBMCs of several patients with asthma or HIE. CONCLUSION: These
results indicate that (1) IgE production in asthma and HIE usually is associated
with elevated levels of IL-4, but not IL-13, in the peripheral blood; (2) the
increased sera IL-4 levels in asthma and HIE are not sufficient to induce Stat6
activation in PBMCs; and (3) evidence of switch recombination to epsilon may be
detected in isolated cases of elevated IgE. This implies that high levels of IgE
in these patients either results from B cells that have already undergone class
switching, from Ig class switching that is localized to target tissues, or both.
PMID- 9768595
TI - Phosphorylation of cytosolic phospholipase A2 by IL-3 is associated with
increased free arachidonic acid generation and leukotriene C4 release in human
basophils.
AB - BACKGROUND: Human basophils secrete leukotriene C4 (LTC4) in response to various
stimuli, and a short treatment with IL-3 enhances LTC4 release, although IL-3
alone does not induce LTC4 release. However, the mechanism of this priming effect
of IL-3 for LTC4 generation remains unknown in human basophils. OBJECTIVE: This
study was designed to explore the mechanisms by which short treatments with IL-3
enhance stimulated secretion of LTC4, with a focus on the activation of cytosolic
phospholipase A2 (cPLA2). METHODS: The phosphorylation state of cPLA2 in human
basophils was examined by its shift in electrophoretic mobility as detected by
Western blotting. Free arachidonic acid (AA) and LTC4 were measured by gas
chromatography-negative ion chemical ionization mass spectrometry and LTC4
specific RIA, respectively. RESULT: Human basophils expressed cPLA2. IL-3, as
well as the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate,
caused a shift in the electrophoretic mobility of cPLA2, which indicated
phosphorylation of cPLA2 and therefore its activation. Ionomycin at a
concentration of 0.1 microg/mL was used to induce a modest elevation of cytosolic
calcium response ([Ca2+]I), no apparent cPLA2 phosphorylation, and little free AA
and LTC4 generation. Pretreatment with IL-3 (1 to 10 ng/mL) markedly enhanced
ionomycin (0.1 microg/mL)-mediated AA and LTC4 generation. The concentration
dependence of cPLA2 phosphorylation by IL-3 and its effects on free AA and LTC4
generation were similar. The selective PKC inhibitors, bis-indolylmaleimide II
and Ro-31-8220 inhibited the phorbol 12-myristate 13-acetate-mediated cPLA2
electrophoretic mobility shift, but not the IL-3-mediated shift, suggesting that
the IL-3 effect is PKC independent. Both the anaphylatoxin split product of the C
component C5 (C5a) and f-Met-Leu-Phe induced PKC-independent cPLA2
phosphorylation with a similar time course most notable for the absence of
observable changes in cPLA2 phosphorylation before 30 seconds. These results
suggested an explanation for the absence of free AA generation by C5a. When
[Ca2+]I was elevated in response to C5a, there was no phosphorylation of cPLA2,
and by the time cPLA2 became phosphorylated, [Ca2+]I had returned to resting
levels. Treatment with IL-3 preconditioned the cPLA2 by causing its
phosphorylation so that the transient [Ca2+]I response, which followed
stimulation by C5a, could induce the generation of free AA and LTC4. CONCLUSION:
Taken together, these results suggest that the effect of IL-3 for free AA
generation and LTC4 release might be due to induction of cPLA2 phosphorylation.
The studies demonstrated a need for synchronous cPLA2 phosphorylation and
elevations in [Ca2+]I.
PMID- 9768596
TI - Effect of angiotensin II receptor blockade on bronchial responsiveness in
asthmatic subjects.
PMID- 9768597
TI - Cytogenetic abnormalities and their lack of relationship to the Asp816Val c-kit
mutation in the pathogenesis of mastocytosis.
PMID- 9768598
TI - A survey of Epi-PEN use in patients with a history of anaphylaxis.
PMID- 9768599
TI - Near-fatal anaphylaxis after Hymenoptera venom immunotherapy.
PMID- 9768600
TI - Chloroflourocarbon- and hydrofluoroalkalane-cromolyn sodium for asthma: the issue
of equivalence trials.
PMID- 9768601
TI - Burn treatment.
PMID- 9768602
TI - Use of sponges during laparoscopic surgery.
PMID- 9768603
TI - George Adlington Syme Oration. The surgeon as a leader in cancer care.
PMID- 9768604
TI - Evaluation of 250 free-flap reconstructions after resection of tumours of the
head and neck.
AB - BACKGROUND: Microvascular free-tissue transfer is now the primary method of
reconstruction in many centres. The aim of this study was to evaluate the
applications, complications and limitations of free-flap reconstruction in a
series of patients with tumours of the head and neck. METHODS: This study
reviewed prospectively accessioned computerized records in a dedicated head and
neck database. Patients treated between 1987 and 1995 with a minimum of a 1-year
follow-up were reviewed. There were 242 patients with a mean age of 58 years (172
men and 70 women). The most common tumour sites were oral cavity (42%),
oropharynx (32%) and hypopharynx (11%). Mucosal squamous carcinoma accounted for
87% of primary cancers. RESULTS: Among the 250 free flaps, the radial forearm
flap (205) and free jejunum (25) predominated. There were 21 episodes of vascular
occlusion (8%), failure of 10 flaps (4%) and two patients died peri-operatively
(0.8%). A second free flap was used in five of 10 cases of flap failure. The
fistula rate was 4.4% among 203 patients at risk for this complication, which
comprised four of 178 forearm flaps and five of 25 free jejunal grafts. Four of
16 jaw reconstructions failed. CONCLUSIONS: A 96% success rate was achieved using
free-tissue transfer for head and neck reconstruction. The overall complication
rate was low but jaw reconstruction and free jejunal grafts posed the greatest
problems because of failure of radial bone and fistulas, respectively. The radial
forearm septocutaneous flap was very reliable and remains our mainstay for oral
reconstruction.
PMID- 9768605
TI - Clinical and radiological predictors of complete excision in breast-conserving
surgery for primary breast cancer.
AB - BACKGROUND: Local recurrence after conservative surgery for breast cancer usually
results from growth of residual cancer adjacent to the excised primary tumour or
from multicentric disease. Complete local excision (CLE) confirmed histologically
is essential to ensure that the risk of local recurrence is minimal. This study
was undertaken to determine that clinical or radiological factors may assist the
surgeon at the time of surgery to achieve this aim. METHODS: A retrospective
review of 101 cases treated by conservative surgery identified 70 cases of CLE
and 31 of incomplete local excision (ILE). Clinical, surgical and
histopathological data were taken from hospital records. Mammographic features
and those of specimen X-rays were evaluated without knowledge of the
histopathological outcome of surgery. RESULTS: Complete excision was
significantly associated with type of operation (lumpectomy vs wide local
excision/quadrantectomy, P < 0.003), absence of calcification (P < 0.03) and the
presence of a mass on mammography (P = 0.05). Tumour size (> 2.5 cm) and the
presence of extensive ductal carcinoma in situ (DCIS) were associated with
incomplete excision (P = 0.0005). No relationship was demonstrated with patient
age, breast size, breast density, tumour grade, receptor status, axillary nodal
status or spicules on X-ray and completeness of excision. Specimen X-ray had a
positive predictive value of 94% with CLE. CONCLUSIONS: Clinical and pre
operative mammographic parameters are important for predicting CLE for breast
cancers treated by breast-conserving surgery. Specimen radiology for palpable
lesions can confirm excision of the cancer and permit re-excision of breast
tissue at the time of initial surgery. Its role in determining CLE should be
further evaluated.
PMID- 9768606
TI - The potential impact of breast cancer screening in Hong Kong.
AB - BACKGROUND: Breast cancer is the second most common cancer and cause of death in
women from Hong Kong. The Well Women Clinic at Kwong Wah Hospital offers breast
cancer screening (physical examination and mammography) for women over 40 years
of age. METHODS: Results of screening over a 2-year period revealed an overall
malignancy detection rate of 2.6 per 1000 screens with a strong selection bias
for symptomatic women. RESULTS: Screening only slightly increased the proportion
of stage I cancers detected; of the malignancies detected, a significant
percentage were in situ cancers with doubtful effects on breast cancer mortality.
Teamwork and communication were useful in keeping a low referral rate to the
surgical clinic of 6.1%, as well as a low biopsy rate for mammographic
abnormalities. CONCLUSIONS: A re-evaluation of the real risk of breast cancer in
young women together with the lack of proven value from screening has suggested a
need for reconsideration of offering screening to women 40 years and over in Hong
Kong.
PMID- 9768607
TI - Carcinoma of the male breast: a review and recommendations for management.
AB - BACKGROUND: Male breast cancer is rare and experience of it in any single
institution is limited. The aim of this study was to evaluate the presentation,
management and outcome of male patients with breast cancer treated at Concord
Repatriation General Hospital hospital over a 38-year period and to determine a
best-practice protocol based on the results and a review of the literature.
METHODS: A total of 42 patients were retrospectively reviewed, pathology slides
were re-examined and reclassified where necessary. Outcome was assessed and
compared with results obtained from a literature review. RESULTS: A trend towards
less radical surgery has emerged. Overall 5-year survival was 50%, but, due to
the late age at presentation, more than half the deaths were non-breast cancer
related. One quarter of the patients presented with locally advanced or
metastatic disease. CONCLUSIONS: The presentation, diagnosis pathology and
outcome of breast cancer are similar in men and women, although the disease
occurs at a later age in men. Radical surgery is not required in order to gain
local control, but knowledge of axillary node status is important in determining
prognosis and the need for adjuvant therapy.
PMID- 9768608
TI - One hundred liver resections including comparison to non-resected liver-mobilized
patients.
AB - BACKGROUND: Factors of liver resection associated with postoperative recovery and
survival, the modalities that affect survival with resected colorectal carcinoma
liver metastases, the comparison of liver function of liver-resected to liver
mobilized but not resected patients, and observation of early liver regeneration
volume over time have not been studied prospectively. This study aimed to
prospectively analyse these factors. METHODS: Data were collected prospectively
on 100 consecutive liver resections, and 10 liver-mobilized but not resected
patients by the Hepatobiliary Unit, University of Melbourne, Austin Campus.
Follow-up of patients was 100%. RESULTS: The factors associated with blood loss
were the type of liver resection (P = 0.0001), the length of the operation (P =
0.0001) and a central venous pressure greater than 5 cm of water (P = 0.0008). An
inverse correlation existed between blood loss and long-term survival (P =
0.003). The only predictor for a postoperative complication was the length of the
operation (P = 0.03): a correlation of moderate significance existed between
blood loss and a complication (P = 0.052; confidence interval 0.19-1.17). The 5
year cumulative survival for hepatic resection for colorectal carcinoma Dukes A +
B was 55%; there was a significantly better survival of Dukes A + B compared to
Dukes C (P = 0.03) and also for those 50 years or older, but this did not depend
on whether there were one or more lesions present. Resected patients had a
significantly higher alanine transaminase (ALT), total bilirubin and
international normalized ratio than non-resected patients, but not albumin, total
protein, alkaline phosphatase or aspartate aminotransferase. The serum albumin
fall was similar in both groups, which indicated that loss of liver tissue was
not the cause. The re-resection rate was 8% without mortality and with low
morbidity. Liver volume was restored by 64% (510 +/- 170 cc) by 7 days
postoperatively. CONCLUSIONS: Major hepatic resection can be performed with low
mortality, morbidity and short hospital stay, with a 5-year survival for
colorectal carcinoma better than 50%. Resection needs to be considered more
frequently for curative management. Serum albumin fall is not caused by loss of
liver tissue and blood loss can be controlled by central venous pressure
manipulation and vascular isolation. Re-resection is a safe and rewarding
treatment and needs to be planned at the first resection.
PMID- 9768609
TI - Patterns of serum CEA fall after hepatic arterial chemotherapy as sole therapy
and combined with cryotherapy for colorectal metastases.
AB - BACKGROUND: Hepatic artery chemotherapy (HAC) and cryoablation are treatments for
unresectable liver metastases from colorectal carcinomas. Our centre has
previously published data that describe survival statistics of patients after
each of these treatments. It has also been established that serial serum
carcinoembryonic antigen (CEA) concentrations may be used to monitor disease
progress, and that the magnitude of fall is prognostic for both treatments. The
pattern of fall of CEA following cryotherapy and regional chemotherapy has not
previously been compared. METHODS: In this study, we examined 26 HAC patients and
24 cryotherapy patients. RESULTS: The mean percentage of the pre-treatment CEA
concentration for the HAC group was 60.5% at 50 days and 29.4% at 150 days, and
for the cryotherapy group 24.9% at 50 days and 24.3% at 150 days. Calculating the
difference between means revealed a significantly different mean fall in the
cryotherapy group at 50 days (P < 0.001) and a difference in mean fall at 150
days (P > 0.1) which was not significant. In patients who responded to hepatic
artery chemotherapy, the eventual CEA fall was very similar in magnitude.
CONCLUSIONS: The pattern of fall of CEA differs in these two treatments.
PMID- 9768610
TI - Cryotherapy of the resection edge after liver resection for colorectal cancer
metastases.
AB - BACKGROUND: An involved or inadequate (< 1 cm) resection margin is associated
with a high rate of local tumour recurrence and reduced survival rates after
liver resection for colorectal metastases. This paper assesses whether or not
hepatic cryotherapy of the resection edge is suitable to improve local disease
control. METHODS: From April 1990 to May 1997, we performed cryotherapy of the
resection edge in 44 patients after liver resection for colo rectal liver
metastases with an involved or inadequate resection margin. The reasons for
performing edge cryotherapy instead of extension of resection were: proximity of
hepatic veins or portal sheath (n = 12); avoidance of extended left or right
hemihepatectomy (n = 15); inadequate liver tissue reserve after resection (n =
16); and patient unfit to undergo further major resection (n = 1). Histological
examination showed the resection margin to be involved in 24 patients and close
(< 1 cm) in 20 patients. RESULTS: Two patients died after surgery. Morbidity
consisted of intra-abdominal collections (n = 6), postoperative bleeding (n = 1),
wound infection (n = 1) and transient liver failure (n = 1). At a median follow
up of 19 months, 16 patients are alive and disease-free, 26 patients developed
recurrence and 15 of them died. Nineteen patients developed recurrence which
involved the liver but only five of these were at the resection edge. Median
overall and liver disease-free survival was 33 and 23 months, respectively.
CONCLUSIONS: Cryotherapy of the resection edge after resection of colorectal
liver metastases with involved or inadequate resection margins considerably
improves local disease control and may allow a greater proportion of patients
with liver metastases to undergo potentially curative treatment.
PMID- 9768611
TI - Reoperation for recurrent coronary artery disease: results of 200 consecutive
cases.
AB - BACKGROUND: It is well known that reoperation for recurrent coronary artery
disease is more difficult than primary coronary artery bypass grafting. However,
it is possible to reduce the morbidity and mortality of reoperation to the same
level as the initial procedure with careful surgical technique. METHODS: A
retrospective study of the first 200 patients who underwent redo coronary bypass
grafting was undertaken. RESULTS: In the first 200 cases of redo coronary bypass
grafting at St George Hospital, Sydney (August 1986-January 1995), there were
five in-hospital deaths (2.5%). There was one case of sternal infection (0.5%),
which required surgical debridement, three cases of stroke (1.5%), one case of
postoperative bleeding (0.5%), which required a return to theatre and six cases
(3%) required mechanical ventilation for more than 24 h. The need for major
postoperative support (such as intra-aortic balloon pumping/adrenaline infusion)
was significantly affected by the degree of urgency and the degree of pre
operative ventricular impairment. CONCLUSIONS: The mortality rate of redo
coronary artery bypass grafting in this series is similar to that of primary
surgery described in other reports.
PMID- 9768612
TI - Comparative experience of a simple technique for laparoscopic chronic ambulatory
peritoneal dialysis catheter placement.
AB - BACKGROUND: Chronic ambulatory peritoneal dialysis (CAPD) is now an established
technique for renal dialysis. Patients with renal failure cope poorly with major
surgery and it is vital that the dialysis catheter tip is sited accurately in the
pelvis if long-term catheter function is to be achieved. Laparoscopic placement
of CAPD catheters may have potential advantages for renal patients by avoiding
the morbidity of a laparotomy. METHODS: A retrospective audit was performed of
all CAPD catheters inserted at the John Hunter Hospital over a 2-year period.
Results of laparoscopically inserted catheters and those placed at laparotomy
were compared. RESULTS: Sixty catheters were inserted, 30 laparoscopically and 30
at laparotomy. The mean operative time was 41 min in the laparoscopic patients
and 57 min in the laparotomy patients (P = 0.0001). The mean total dose of
narcotic administered postoperatively was significantly less in the laparoscopic
group (5 mg vs 65 mg, P = 0.00002). There were three minor peri-operative
complications in the laparoscopic group and seven peri-operative complications in
the laparotomy group, three required reoperation and one resulted in the
patient's death. There were no significant differences in the incidence of exit
site infection, catheter blockage, peritonitis, and overall catheter survival,
although the laparoscopically placed catheters had been followed up for a shorter
period (10 vs 16 months). CONCLUSIONS: This laparoscopic technique is safe and
effective. Postoperative pain was less than for open placement. Laparoscopically
placed catheters had a low incidence of peri-operative complications. Medium-term
patency is similar to conventionally placed catheters. This procedure requires no
additional equipment to that available for laparoscopic cholecystectomy and takes
less time than the open operation.
PMID- 9768613
TI - Tumour cell movement during heating and humidification of insufflating CO2: an in
vitro model.
AB - BACKGROUND: Intra-operative hypothermia and port-site recurrence have been
associated with laparoscopic surgery. Heating and humidification of insufflating
CO2 may protect against laparoscopy-associated hypothermia. However, the effect
of heated, humidified CO2 upon tumour cell movement is unknown. METHODS: Twenty
four in vitro studies that used 4-L plastic bottles were performed. Thirteen
million human colorectal cancer cells were placed in each bottle. Twelve studies
used dry room temperature CO2 for insufflation: the remaining 12 used heated,
humidified CO2 as the insufflating gas. Both groups were subdivided into bottles
with leaks around the trocars and with airtight sealing around the trocars. Two
trocars and a laparoscopic grasper were used. The exiting insufflating gas was
filtered and examined for the presence of cells. Laparoscopic instruments
agitated the contents of the bottles. The instruments and trocars were washed.
These washings were examined for the presence of cells. RESULTS: Heated,
humidified CO2 insufflation was able to maintain a warmer and more humid
environment within the bottles when compared with dry room-temperature CO2. No
cells were detected on the gas filters. Tumour cells were found on 12 out of 12
instruments and 11 out of 12 trocars with dry CO2 insufflation. Tumour cells were
found on 8 out of 12 instruments and 7 out of 12 trocars with heated humidified
CO2 insufflation. The only statistically significant difference in tumour cell
spread to trocars was found between heating and humidification when no leak was
present, and heating and humidification with leak present, and dry insufflation
with no leak present (P = 0.015, Fisher's two-tailed exact test). CONCLUSIONS:
Heating and humidifying CO2 during in vitro laparoscopy does not increase the
aerosolization of tumour cells when compared with dry CO2. However, the use of
heated and humidified gas with airtight seals around the trocars in vitro may
lessen cell deposition on trocars.
PMID- 9768614
TI - Treatment of large, persistent lymphocoeles using an argon beam coagulator and
talc.
AB - BACKGROUND: Lymphocoele formation can be a troublesome surgical complication
after lymph node dissection and mobilization of large skin flaps. Occasionally,
lymphocoeles persist for prolonged periods despite repeated aspiration. Treatment
by sclerotherapy has been recommended, but this requires a prolonged treatment
time and often causes intense pain. METHODS: The technique used to treat large,
persistent lymphocoeles involved 'painting' the lymphocoele wall with an argon
beam coagulator after evacuating its contents. Sterile talc was then distributed
liberally through the cavity, a closed suction drain placed and the wound closed.
RESULTS: The procedure was completely successful in each of the four patients
treated. After a mean follow-up period of 11 months (range 6-15 months) no
lymphocoele recurrence has occurred. CONCLUSIONS: Use of an argon beam coagulator
and talc reliably achieves rapid, definitive obliteration of large, persistent
lymphocoeles.
PMID- 9768615
TI - A simple method of wound protection for specimen removal in laparoscopic
colectomy.
PMID- 9768616
TI - The Murray Clarke Oration: a brief history of burn treatment and the contribution
of four New Zealand pioneers of plastic surgery.
PMID- 9768617
TI - Analysis of a large collection of natural HIV-1 integrase sequences, including
those from long-term nonprogressors.
AB - A large collection of natural HIV-1 integrase (IN) sequences has not previously
been described. We reasoned that analysis of such sequences would address whether
natural variation of HIV-1 IN contributes to the pathogenesis of AIDS and might
also identify amino acid residues important for IN function. Sequences encoding
HIV-1 IN were amplified from cryopreserved lymphocytes or plasma obtained at
different times from 10 hemophilia patients who had been observed for up to 17
years. The region of the HIV-1 genome that encodes the 288-amino acid IN protein
was sequenced from a total of 102 clones; information was obtained for 99.97% of
29,478 amino acid positions. Phylogenetic analysis indicated that patient samples
were unique. Interpatient nucleic acid distances ranged from 0.8% to 4.9%,
highlighting the tight conservation of this genomic region. No major differences
were found between DNA and RNA or between early and late time points from the
same patient. Significantly, no amino acid changes that might account for the
variable rate of disease progression between patients were evident. Only one
amino acid substitution involved a highly conserved residue known to be important
for enzymatic activity. However, several interesting amino acid substitutions
were noted, including residues within the C-terminal region of the protein for
which sequence comparisons between animal retroviruses have not been very
informative. These results should encourage the pursuit of anti-integrase
therapies, especially inasmuch as the apparent biologic constraints on the IN
sequence may deter the development of drug resistance.
PMID- 9768618
TI - Effective lysis of HIV-1-infected primary CD4+ T cells by a cytotoxic T
lymphocyte clone directed against a novel A2-restricted reverse-transcriptase
epitope.
AB - Most HIV-specific cytotoxic T-lymphocyte (CTL) epitopes have been identified
using peptide-pulsed and recombinant vaccinia virus-infected targets. These
systems may not accurately reflect the ability of epitopes to be presented by HIV
infected T cells. Recent studies suggest, in fact, that some CTL epitopes are
poorly presented on HIV-infected cells. In this study, we have identified a novel
A2.1-restricted HIV reverse-transcriptase (RT) epitope and investigated the
presentation of this epitope by HIV-infected primary CD4+ T cells and T-cell
lines. A CD8+ CTL clone, isolated from a seropositive subject that recognized a
novel A2-restricted epitope KYTAFTIPSI (aa 293-302) in RT, was used for these
studies. Primary CD4+ T cells and the CD4+ T-cell line T1 were infected with
virus from T1-nPLAP, a cell line stably transfected with HXB-nPLAP, a molecular
construct of HIV linked to a placental alkaline phosphatase (PLAP) marker gene. A
uniformly infected cell population, obtained by immunomagnetic selection for PLAP
expression, was used as targets in CTL assays. HIV-infected T cells were lysed by
CTL recognizing this RT epitope as effectively as peptide-pulsed targets. This
suggests that some RT epitopes are good targets for CTL recognition.
PMID- 9768619
TI - Altered cell-mediated immunity in asymptomatic Colombian natives with positive or
indeterminate serology for HTLV-I.
AB - Although HTLV-I infection has been associated with immunosuppression in
symptomatic patients, no controlled study has been done in asymptomatic carriers.
We evaluated delayed-type hypersensitivity (DTH) to seven antigens by multitest
cell-mediated immunity (CMI) in 40 Colombian Indians, 10 HTLV-I-seropositive
asymptomatic patients, and 30 matched controls. Multitest CMI was placed in the
forearm and was read 48 hours later by the same physician. A positive reaction
was defined as > or =2 mm. Hypoergic response was defined as <2 of 7 positive
reactions per case or control. We found that HTLV-I-seropositive people had fewer
positive reactions than matched controls (50% versus 64%, respectively; p < .04)
but no significant difference was found in these populations in the evaluation of
hypoergic responses. This study suggests the presence in asymptomatic HTLV-I
positive Colombian Indians of a marginal alteration of cell-mediated immunity
that cannot be classified as hypoergic.
PMID- 9768620
TI - Effect of antiretroviral therapy and viral load on the perceived risk of HIV
transmission and the need for safer sexual practices.
AB - BACKGROUND: Dramatic reductions in plasma HIV RNA levels are possible with
current antiretroviral regimens; the effect of potent therapies and
"undetectable" viral load on the perceived risk of HIV transmission and need for
safer practices remains unknown. METHODS: A questionnaire was developed to
examine perceptions of HIV transmission risk and need for safer practices with
unprotected anal, vaginal, and oral sex and intravenous drug use with needle
sharing for HIV-discordant couples in which the HIV-infected partner was
receiving no therapy, was receiving reverse transcriptase inhibitor therapy, and
protease inhibitor (PI)-based therapy with viral load "undetectable". This was
applied anonymously to 147 unselected HIV-infected individuals attending a
university-based HIV clinic. RESULTS: Almost all respondents believed that all
sexual activities except oral sex were "very risky" and that safer practices were
"extremely important" for those not receiving antiretroviral agents.
Significantly fewer considered that anal or vaginal sex was "very risky" for
those receiving PI therapy (90.9% and 86.0%, respectively), and fewer thought
that safer practices for anal or vaginal sex were "very important" for those
receiving PI therapy (93.0% and 91.6%, respectively). In total, 20.4% thought the
risk of HIV transmission for at least one activity was reduced for those
receiving PI therapy, and 19.0% believed that the need for safer practices was
reduced by PI therapy. CONCLUSION: A small but significant proportion of HIV
infected people perceive the need for safer practices to be reduced during
antiretroviral therapy, particularly those containing PIs. Even if the risk is
truly reduced, the importance of safer practices should be conveyed consistently
and terms such as "undetectable" to describe HIV RNA responses should be avoided.
PMID- 9768621
TI - Improved outcome of cytomegalovirus retinitis in AIDS patients after introduction
of protease inhibitors.
AB - The objective of this study was to evaluate the influence of protease inhibitor
therapy on the rate of progression and survival of 17 AIDS patients with stable
Cytomegalovirus retinitis, who were receiving anti-CMV therapy. CD4+ count, HIV
load, and CMV antigenemia assay were determined at baseline, at the first month,
and every 3 months thereafter. Median CD4+ count increased from 11 to 87
cells/mm3, and median HIV RNA level decreased from 4.96 to 3.28 log10 copies/ml,
after 6 months on therapy. Although 9 patients (53%) relapsed in a median time of
97 days (range, 15-152 days), no further episodes were observed during a median
follow-up of 17 months (range, 5-18 months). Thus, the probability of remaining
free of relapse was twofold higher than that observed in matched patients who did
not receive protease inhibitors. Median CD4+ count at the 3rd month was higher in
those individuals who went on to progress (p = .03), and a positive result to a
CMV antigenemia test was associated with progression of retinitis (relative
hazard, 4.45; p = .04). Survival rate was 94% at 17 months (89% increase).
Therefore, protease inhibitor therapy reduces retinitis progression and improves
survival. However, the immunologic response may not provide initial sufficient
protection to avoid, or even may play a role on, early CMV progression.
PMID- 9768622
TI - Phase I study of atevirdine mesylate (U-87201E) monotherapy in HIV-1-infected
patients.
AB - The safety, tolerability, and antiviral activity of atevirdine (ATV), a
nonnucleoside reverse transcriptase inhibitor, were studied in a phase I/II
clinical trial (ACTG 187) of patients with CD4 counts < or =500/mm3. In all, 34
HIV-1-infected patients were randomized to receive ATV for 12 weeks in doses
chosen to achieve one of three serum trough levels: 5 to 13 microM, 14 to 22
microM, or 23 to 31 microM. Rash was the most common adverse event, with a grade
3 or 4 rash occurring in 4 patients. No significant change from baseline in HIV-1
plasma RNA mean copy number was detected at week 4 (+0.09 log10 copies/ml; p =
.30). However, some evidence indicated moderate antiviral activity at week 4,
based on median changes in CD4 count (+23/mm3; p = .05), and viral peripheral
blood mononuclear cell (PBMC) titer (-0.68 log10) copies/ml; p = .03). In
addition, 2 of 4 patients with detectable baseline serum p24 antigen showed
declines of >50%. HIV-1 resistance to ATV was detected in 41% of patients and was
most commonly associated with RT mutations K103N and Y181C. In contrast, the
Y181C mutation was not detected in ATV-resistant isolates obtained from patients
enrolled in ACTG 199, a study of ATV given in combination with zidovudine. Under
the conditions of this study, ATV failed to demonstrate significant
antiretroviral activity. However, transient in vivo activity might have been
obscured by rapid development of resistance coupled with inadequate sampling at
early time points following initiation of ATV therapy.
PMID- 9768623
TI - Decreased susceptibility of peripheral blood mononuclear cells from individuals
heterozygous for a mutant CCR5 allele to HIV infection.
AB - OBJECTIVE: Individuals homozygous for a deletion in the CCR5 gene
(CCR5delta32/CCR5delta32) are resistant to HIV infection, indicating that this
particular chemokine receptor plays a crucial role in the initiation of in vivo
HIV infection. We investigated the effect of the heterozygote genotype
(CCR5/CCR5delta32) on susceptibility of peripheral blood mononuclear cells (PBMC)
to HIV infection. DESIGN: Sensitivity to HIV infection of PBMC from volunteers
with either the CCR5/CCR5, CCR5/CCR5delta32, or CCR5delta32/CCR5delta32 genotypes
was examined by challenging their PBMCs with serial titers of HIV isolates with
different cellular tropisms. The genotype of the PBMCs was correlated with the
lowest viral inoculum required to initiate productive infection with either three
M-tropic HIV-1 isolates, (92RW009A, HIV-1ada, and HIV-1(59)), one dual-tropic HIV
1 isolate (92BR021), or two T-tropic HIV-1 isolates (92UG021 and 92UG029).
RESULTS: PBMCs from the CCR5/CCR5delta32 group required a significantly higher
inoculum (p value from .036 to .003) to become infected with these three M-tropic
HIV-1 isolates than did PBMC from the CCR5/CCR5 group, but became infected after
exposure to an inoculum of T-tropic HIV-1 isolates that was comparable to that
which infected PBMCs from the CCR5/CCR5 individuals. CONCLUSIONS: The decreased
susceptibility of PBMCs from individuals heterozygous for the CCR5 deletion to
HIV infection by M-tropic HIV-1 isolates may provide a mechanistic explanation
for the delayed progression of disease in some CCR5/CCR5delta32 individuals.
PMID- 9768624
TI - Resting energy expenditure and body composition in children with HIV infection.
AB - The purpose of this study was to determine whether alterations in body
composition, resting energy expenditure (REE), and dietary energy intake are
associated with growth retardation in HIV-positive children. Body composition
(deuterium oxide dilution, skinfold measurements), REE (indirect calorimetry),
and energy intake (24-hour weighed food intake) were evaluated in three groups:
HIV-positive with growth retardation (HIV+Gr), HIV-positive with normal growth
(HIV+); and HIV-uninfected with normal growth (HIV-). Children were between 2 and
11 years of age, afebrile, and free from acute infection. Forty-two children (13
HIV+Gr, 19 HIV+, 10 HIV-) were studied. Lean body mass was significantly reduced
in HIV+Gr compared with HIV- (p < .05), and fat mass was significantly reduced in
HIV+Gr and HIV+ compared with HIV- (p < .05). The percentages of lean and fat
mass were not significantly different between groups, suggesting that differences
in lean and fat mass were proportional to differences in body size. Consistent
with reduced lean body mass, mean REE was significantly lower in HIV+Gr compared
with HIV- (p < .05). Differences in mean REE/kg of body weight or lean body mass
between groups were not statistically significant. A significant negative
correlation was found between REE (kcal/kg/day) and weight-for-age (p = .04), and
a trend with height-for-age Z-score (p = .07). Mean energy intake was not
significantly different between groups. This study suggests that lean and fat
mass are proportionately reduced in HIV-positive children with growth
retardation. Further studies are necessary to delineate the relationship between
energy balance and growth in children with HIV infection.
PMID- 9768625
TI - Trends in HIV prevalence among childbearing women in the United States, 1989
1994.
AB - We used data from a national serosurvey to describe national and regional trends
in the prevalence of HIV among women giving birth in the United States from 1989
through 1994, and to estimate the number of women between 15 and 44 years old
with HIV infection who had not yet developed opportunistic infections defining
AIDS. We compared these estimates with AIDS prevalence and mortality estimates
from the national AIDS case surveillance system. HIV seroprevalence among
childbearing women remained stable nationwide from 1989 through 1994, ranging
from 1.5 to 1.7/1000 women. In the Northeast, seroprevalence declined
significantly after 1989. Seroprevalence increased significantly in the South
through 1991 and then stabilized, although seroprevalence among black women
continued to increase through 1994 in some southern states. Although AIDS
prevalence and mortality increased nationwide each year from 1989 through 1994,
the number of women infected with HIV who had not yet developed AIDS changed
little and was approximately 86,000 in 1994. Our data suggest that new HIV
infections among women of reproductive age are occurring at a rate that offsets
losses from this population due to aging, disease progression, and death.
PMID- 9768626
TI - Nationwide surveillance of HIV-1 prevalence and subtype in young Thai men.
AB - As part of routine surveillance, an HIV-1 serosurvey of 366,074 members of
successive cohorts of young Thai men entering service with the Royal Thai Army
(RTA) was conducted between November 1989 and November 1995. We analyzed regional
and temporal trends in HIV-1 seroprevalence in young men in Thailand and
determined the proportion of infections resulting from subtypes E and B in this
population in 1992 and 1995. The prevalence in 1992 was compared with that in
1995 by region and demographic group. The HIV-1 subtype was determined in a
random sample of HIV-1-positive specimens in 1992 and 1995 using a V3 peptide
enzyme immunoassay. From a peak of 3.7% in 1993, overall seroprevalence declined
to 3.0% in 1994 and further in 1995 to 2.5%. Between 1992 and 1995, the absolute
decrease in seroprevalence was greatest in the upper North (from 12.5% to 5.3%),
where the prevalence has been the highest. Overall, 96.9% and 95.9% of typable
specimens were determined to be subtype E in 1992 and 1995, respectively. Decline
in HIV-1 seroprevalence among young men in Thailand has continued, which suggests
that HIV control programs in Thailand may have been successful in decreasing
spread of HIV-1. Almost all HIV-1 infections resulted from subtype E.
PMID- 9768627
TI - Distribution of the CCR5 gene 32-bp deletion in Europe.
AB - The chemokine receptor CCR5 constitutes the major coreceptor for the macrophage
tropic strains of HIV-1. A mutant allele of the CCR5 gene called delta32 was
shown to provide strong resistance to homozygotes against infection by HIV. The
frequency of the delta32 allele was investigated in 2522 noninfected unrelated
individuals from 16 different European populations. The delta32 allele was found
in all populations studied, with a mean frequency of about 9.1%. A north-to-south
gradient correlating latitude with delta32 allelic frequencies was found (r =
0.726), with highest allele frequencies in Denmark and Northern France, and the
lowest allele frequencies in Corsica.
PMID- 9768628
TI - Continuing high prevalence of HIV and risk behaviors among young men who have sex
with men: the young men's survey in the San Francisco Bay Area in 1992 to 1993
and in 1994 to 1995.
AB - Several recent studies have shown high rates of HIV infection and risk behavior
among young men who have sex with men (MSM). To assess the direction of the
epidemic in this population, we replicated a venue-based study performed in the
San Francisco Bay Area during 1992 and 1993. From May 1994 to September 1995, we
surveyed 675 MSM aged between 17 and 22. After statistical adjustment for age,
ethnicity, residence, and site of recruitment, seroprevalence did not change
significantly between the 1992 to 1993 (8.4%) and the 1994 to 1995 (6.7%)
surveys. Similarly, no significant changes were found in the rates during the
previous 6 months of unprotected receptive anal intercourse (23.4% versus 24.9%),
injection drug use (8.0% versus 7.8%), or needle sharing among injection drug
users (56.3% versus 64.5%) between the two surveys. Despite the increased
attention that the problem of high risk behavior among young MSM has received,
effective prevention interventions for MSM are needed as profoundly now as they
had been several years ago.
PMID- 9768629
TI - Pneumocystis carinii pneumonia incidence and chemoprophylaxis failure in
ambulatory HIV-infected patients. HIV Outpatient Study (HOPS) Investigators.
AB - BACKGROUND: Pneumocystis carinii pneumonia (PCP) remains the most frequently
reported serious opportunistic infection in AIDS patients and the second highest
cause of mortality among persons with AIDS in the United States, despite the
availability of effective chemoprophylaxis. METHODS: To evaluate incidence of PCP
and determinants of PCP chemoprophylaxis failure, we analyzed data from 2842
patients visits to infectious diseases physicians at 10 HIV clinics (eight
private and two public) in eight U.S. cities from January 1992 through June 1996
as part of the HIV Outpatient Study (HOPS). We performed a time-dependent
regression analysis to examine potential determinants of PCP chemoprophylaxis
failure. RESULTS: The incidence of chemoprophylaxis failure was 4.6 PCP cases/100
person-years on chemoprophylaxis; these cases represent 67% of all incident
episodes of PCP. In a multivariate analysis, the only significant predictors of
chemoprophylaxis failure were the use of agents other than trimethoprim
sulfamethoxazole (TMP-SMX), history of prior PCP, and a CD4+ T-lymphocyte cell
count of <50 cells/microl. Dosing or frequency of TMP-SMX did not seem to
influence risk of chemoprophylaxis failure. DISCUSSION: Chemoprophylaxis failure,
especially among those with the most advanced immunosuppression or history of
prior PCP, was the most significant source of new PCP cases in the HOPS cohort
and thus represents one of the largest contributors to morbidity and mortality in
this cohort.
PMID- 9768630
TI - Infant feeding and risk of mother-to-child transmission of HIV-1 in Sao Paulo
State, Brazil. Sao Paulo Collaborative Study for Vertical Transmission of HIV-1.
AB - Although vertical transmission of HIV-1 can occur through breast-feeding, little
is known about the effect of colostrum, duration of breast-feeding, mixing
feeding, and nipple pathology. We used retrospective cohort data to examine the
association between breast-feeding-related factors and transmission of HIV-1 from
mother to child in Sao Paulo State, Brazil. Information on maternal and postnatal
factors was collected by medical record review and interview. Infection status
was determined for 434 children by anti-HIV-1 tests performed beyond 18 months of
age or diagnosis of AIDS at any age. Among 168 breast-fed children, the risk of
transmission of HIV-1 was 21%, compared with 13% (p = .01) among 264 children
artificially fed. Breast-feeding was independently and significantly associated
with mother-to-child transmission of HIV-1 after controlling for stage of
maternal HIV-1 disease (odds ratio [OR] = 2.2; 95% confidence interval [CI], 1.3
3.8). A trend was shown toward an increased risk of transmission with longer
duration of breast-feeding, a history of bleeding nipples, and introduction of
other liquid food before weaning, but these associations were not statistically
significant. History of colostrum intake or cracked nipples without bleeding were
not associated with transmission. Most of the women who breast-fed were unaware
of their HIV-1 infection status at the time of delivery. Avoidance of mixed
feeding and withholding of breast-feeding in the presence of bleeding nipples
should be considered in further research as strategies to reduce postnatal
transmission of HIV-1 in settings in which safe and sustainable alternatives for
breast-feeding are not yet available.
PMID- 9768631
TI - Selecting the optimum dose for a new soft gelatin capsule formulation of
saquinavir. NV15107 Study Group.
PMID- 9768632
TI - Cotton-wool spots in primary HIV infection.
PMID- 9768633
TI - Rapid progression of HIV infection in HBeAg-positive patients.
PMID- 9768634
TI - HIV prevalence among injection drug users in three Northern California
communities.
PMID- 9768635
TI - Autoimmune thyroid disease genes come in many styles and colors.
PMID- 9768636
TI - Linkage disequilibrium between the human leukocyte antigen class II region of the
major histocompatibility complex and Graves' disease: replication using a
population case control and family-based study.
AB - Early case control studies found association of the DRB1 allele, DR3, with
Graves' disease (GD). Recent reports, claim the DQA1 allele, DQA1*0501, to be the
primary susceptibility determinant within the human leukocyte antigen (HLA) class
II region. We typed 228 GD patients, 364 controls, and 98 families (parents, GD,
and unaffected sibling) at the DRB1, DQB1, and DQA1 loci. The case control study
showed an increased frequency in GD, compared to controls, of DRB1*0304 (47% vs.
24%; pc < 1.4 x 10(-5)), DQB1*02 (58% vs. 46%; pc < 0.035), DQB1*0301/4 (42% vs.
28%; pc < 3.5 x 10(-3)) and DQA1*0501 (67%, vs. 39%; pc < 7 x 10(-6)). The
DRB1*0304-DQB1*02-DQA1*0501 haplotype was increased in GD (47%) vs. controls
(24%; pc < 1.8 x 10(-5); odds ratio = 2.72). No independent association of these
alleles was observed. Preferential transmission of DRB1*0304-DQB1*02-DQA1*0501
from parents heterozygous for the haplotype to GD siblings (72%) was seen in the
families (chi2 = 11.95; 1 d.f.; P = 0.0005). Lack of preferential transmission to
unaffected siblings (53%; chi2 = 0.19; 1 d.f.; P = NS) excluded segregation
distortion. These results show that linkage disequilibrium between GD and the HLA
class II region is due to the extended haplotype DRB1*0304-DQB1*02-DQA1*0501.
PMID- 9768637
TI - What's happening to our iodine?
PMID- 9768638
TI - Iodine nutrition in the United States. Trends and public health implications:
iodine excretion data from National Health and Nutrition Examination Surveys I
and III (1971-1974 and 1988-1994)
AB - Iodine deficiency in a population causes increased prevalence of goiter and, more
importantly, may increase the risk for intellectual deficiency in that
population. The National Health and Nutrition Examination Surveys [NHANES I (1971
1974) and (NHANES III (1988-1994)] measured urinary iodine (UI) concentrations.
UI concentrations are an indicator of the adequacy of iodine intake for a
population. The median UI concentrations in iodine-sufficient populations should
be greater than 10 microg/dL, and no more than 20% of the population should have
UI concentrations less than 5 microg/dL. Median UI concentrations from both
NHANES I and NHANES III indicate adequate iodine intake for the overall U.S.
population, but the median concentration decreased more than 50% between 1971
1974 (32.0+/-0.6 microg/dL) and 1988-1994 (14.5+/-0.3 microg/dL). Low UI
concentrations (<5 microg/dL) were found in 11.7% of the 1988-1994 population, a
4.5-fold increase over the proportion in the 1971-1974 population. The percentage
of people excreting low concentrations of iodine (UI, <5 microg/dL) increased in
all age groups. In pregnant women, 6.7%, and in women of child-bearing age, 14.9%
had UI concentrations below 5 microg/dL. The findings in 1988-1994, although not
indicative of iodine deficiency in the overall U.S. population, define a trend
that must be monitored.
PMID- 9768639
TI - Tight control of growth hormone: an attainable outcome for acromegaly treatment.
PMID- 9768640
TI - Transsphenoidal microsurgery for growth hormone-secreting pituitary adenomas:
initial outcome and long-term results.
AB - Treatment of acromegaly has long been recognized as necessary to relieve
symptoms, halt progression of deformities, and decompress the sella turcica. More
recently, treatment strategies have focused on decreasing GH levels to a point at
which mortality rates normalize, thereby redefining previous concepts of a cure.
No surgical series to date has investigated the long-term effect of treatment on
mortality rates. We retrospectively reviewed 254 consecutive patients with
acromegaly who underwent transsphenoidal microsurgery of GH-secreting adenomas
between 1974-1992. Seventy-six percent of these patients had basal GH levels <5
ng/mL within 30 days of surgery, and 24% had persistent disease. Multivariate
analysis revealed that higher stage, grade, and preoperative GH levels were all
predictive of persistence (P < 0.01). Long-term follow-up was obtained on 129 of
the patients in initial remission. Of these, 9 (7%) had disease recurrence and
120 remained in remission. The incidence of major postoperative complications was
8% (2% permanent diabetes insipidus, 2% cerebrospinal fluid leaks requiring
surgery, 2% meningitis, and 2% hypopituitarism), with no mortality. In contrast
to the 2.4- to 4.8-fold increased mortality among untreated acromegalics, the
mortality rate among patients with posttherapy GH levels <5 ng/mL was equivalent
to that of age- and sex-matched controls. Aggressive therapy to normalize GH
levels should therefore be instituted at diagnosis.
PMID- 9768641
TI - Long-term mortality after transsphenoidal surgery and adjunctive therapy for
acromegaly.
AB - To analyze the long term outcome after multimodality therapy for acromegaly, a
retrospective review was performed on 162 patients who underwent transsphenoidal
surgery at Massachusetts General Hospital between 1978 and 1996. The surgical
cure rate for microadenomas was 91%, that for macroadenomas was 48%, and it was
57% overall. The surgical cure rate was significantly dependent on tumor size,
but was not dependent on age or sex. An improvement in the surgical cure rate was
noted over the course of the review, from 45% before 1987 to 73% since 1991. Long
term follow-up was obtained in 99% of U.S. residents (149 of 151), with a mean
follow-up period of 7.8 yr. Adjuvant radiation and/or pharmacological therapy was
given to 61 patients. Of the entire group, 83% (124 of 149) were in biochemical
remission as determined by normalization of serum insulin-like growth factor I
levels or by GH suppression after oral glucose tolerance testing at last contact
or at death. The recurrence rate was 6% at 10 yr and 10% at 15 yr after surgery
in those patients who initially met the criteria for surgical cure. The 10-yr
survival rate was 88%, and there were 12 deaths at postoperative intervals of 2
12 yr, with the most common cause of death being cardiovascular disease. A Cox
proportional hazards model showed that patient-years with persistent disease
carried a 3.5-fold [95% confidence interval (CI), 1.0-12; P = 0.02] relative
mortality risk compared to those patient-years in remission. A Poisson person
years regression analysis showed no significant difference in survival between
those 86 patients cured at operation and an age- and sex-matched sample from the
U.S. population [standardized mortality ratio (SMR), 0.84; 95% CI, 0.3-2.2; P =
0.35]. A similar analysis on the entire group of 149 patients showed no
significant difference in survival from that in a control sample (SMR, 1.16; 95%
CI, 0.66-2.0; P = 0.3). Mortality risk for patient-years with persistent active
disease after unsuccessful treatment vs. that in the U.S. population sample
remained increased (SMR, 1.8; 95% CI, 0.9-3.6; P = .05). This analysis suggests
that the decreased survival previously reported to be associated with acromegaly
can be normalized by successful surgical and adjunctive therapy.
PMID- 9768642
TI - Profiles of the Endocrine Clinic: the Mayo Clinic.
AB - It is evident that clinical endocrinology, as a discipline, is entering a
particularly exciting period in its evolution. Knowledge gained from basic and
clinical research is being translated at the bedside for the benefit of our
patients. The emergence of new drugs and novel treatment strategies has equipped
clinical endocrinologists with the tools to more successfully combat many old
enemies, such as diabetes and osteoporosis. Realization of full benefit from
these exciting new tools requires a practice model in which the clinical
endocrinologist's role is preeminent and is coordinated and integrated with those
of practitioners drawn from other disciplines. The Mayo Division of
Endocrinology, Metabolism, and Nutrition provides one such model of highly
integrated care. We believe that as the pace of knowledge regarding basic
mechanisms of disease and their treatment quickens, such integrated divisions
will prove well suited to deliver the highest quality care to people with
endocrine disorders.
PMID- 9768643
TI - Issues in testosterone replacement in older men.
PMID- 9768644
TI - A spontaneous and severe hyperstimulation of the ovaries revealing a gonadotroph
adenoma.
AB - We report an unusual case of a gonadotroph adenoma in a 34-yr-old woman, revealed
by a dramatic rise in the plasma estradiol (E2) concentration (26,800 pmol/L;
normal, <370), with nonsuppressed FSH and LH levels (4.9 and 2.4 mIU/mL,
respectively). The PRL level was 503 ng/mL. The testosterone and progesterone
levels were 7 and 17 nmol/L, respectively. The levels of inhibin alpha, inhibin
A, and inhibin B were increased compared to normal values in both the follicular
(fp) and luteal (lp) phases of the menstrual cycle [inhibin alpha, 1986 IU/L (fp
normal, <700; lp normal, <1650); inhibin A, 254 pg/mL (fp normal, <20; lp normal,
<120); inhibin B, 246 pg/mL (fp normal, <150; lp normal, <30 lp)]. Pituitary
magnetic resonance imaging revealed a huge pituitary adenoma. After
transphenoidal surgery, the patient presented with pituitary insufficiency and
diabetes insipidus. RT-PCR of the tumor tissue was positive for LHbeta, FSHbeta,
alpha-subunit, and PRL. This case is of particular interest because 1) although
the E2 level was extremely high, the patient did not present with ascitis,
suggesting that chronic elevated E2 does not play a crucial role in the
hyperstimulation symptoms; 2) the extreme rise in E2 was related to the
cosecretion of FSH and LH, confirming the two-cell two-gonadotropin theory; and
3) the rise in inhibin B is associated with FSH secretion, whereas the rise in
inhibin A is probably due to luteinization.
PMID- 9768645
TI - An unusual pituitary pathology.
PMID- 9768646
TI - A PHEX gene mutation is responsible for adult-onset vitamin D-resistant
hypophosphatemic osteomalacia: evidence that the disorder is not a distinct
entity from X-linked hypophosphatemic rickets.
AB - Previous investigators described a kindred with an X-linked dominant form of
phosphate wasting in which affected children did not have radiographic evidence
of rickets, whereas older individuals were progressively disabled by severe
bowing. They proposed that this kindred suffered from a distinct disorder that
they referred to as adult-onset vitamin D-resistant hypophosphatemic osteomalacia
(AVDRR). We recently identified a gene, PHEX, that is responsible for the
disorder X-linked hypophosphatemic rickets. To determine whether AVDRR is a
distinct form of phosphate wasting, we searched for PHEX mutations in affected
members of the original AVDRR kindred. We found that affected individuals have a
missense mutation in PHEX exon 16 that results in an amino acid change from
leucine to proline in residue 555. Clinical evaluation of individuals from this
family indicates that some of these individuals display classic features of X
linked hypophosphatemic rickets, and we were unable to verify progressive bowing
in adults. In light of the variability in the clinical spectrum of X-linked
hypophosphatemic rickets and the presence of a PHEX mutation in affected members
of this kindred, we conclude that there is only one form of X-linked dominant
phosphate wasting.
PMID- 9768647
TI - Peak bone mass in young healthy men is correlated with the magnitude of
endogenous growth hormone secretion.
AB - GH plays a key role during adolescence in longitudinal bone growth and the
attainment of peak bone mass. We explored the hypothesis that in early adulthood,
bone mineral accretion and/or maintenance in men with normal GH and bone mineral
status are related to the magnitude of endogenous GH secretion. Overnight plasma
GH concentrations (sampled every 10 min from 2100-0500 h) were measured in 15
healthy, lean, Caucasian men (age, 24+/-1 yr; body mass index, 22.6+/-0.6 kg/m2;
mean +/- SE). Total body, femur, and lumbar spine bone mineral mass/density were
measured by dual energy x-ray absorptiometry. Total body and femoral bone mineral
mass correlated with both total nocturnal GH and maximal GH concentrations even
when bone mineral mass was adjusted by height (P = 0.005-0.02; r = 0.58-0.74).
Neither spinal nor total body bone mineral density (BMD) correlated with GH.
Maximum GH correlated with the BMD of all four femoral sites (P = 0.01-0.04; r =
0.55-0.66), whereas total nocturnal GH correlated with only one (trochanter; P =
0.01; r = 0.64) femoral site. Our data support the hypothesis that GH continues
to play a role in the accretion and/or maintenance of bone mass in young men.
This relationship is more evident in the bone mineral mass achieved than in the
BMD.
PMID- 9768648
TI - Effect of obesity on estradiol level, and its relationship to leptin, bone
maturation, and bone mineral density in children.
AB - The purpose of this study was to investigate 24-h estradiol and leptin levels in
obese and nonobese children to further understand the roles of estradiol and
leptin in obesity and puberty. We measured serum estradiol, leptin, insulin,
glucose, and GH levels every hour for 24 h in 18 obese (12 females and 6 males)
and 30 nonobese (11 females and 19 males) prepubertal and early pubertal (stages
1-2) children. Bone age and dual energy x-ray absortiometry (DEXA) were obtained
upon completion of the 24-h study. Obese children were significantly younger than
nonobese children, with no difference in pubertal stage, height, or bone age
between the 2 groups. Obese children had greater bone age to chronological age
ratios than nonobese children, indicating a more advanced rate of bone
maturation. Mean 24-h estradiol levels correlated significantly with
chronological age and bone age as well as with insulin-like growth factor I,
insulin-like growth factor-binding protein-3, dehydroepiandrosterone sulfate,
mean 24-h GH, and lean body mass. Mean 24-h estradiol levels did not differ
between obese and nonobese children [1.65+/-1.47 us. 2.75+/-3.30 pmol/L (0.45+/
0.40 vs. 0.75+/-0.90 pg/mL), respectively]. Similar mean 24-h estradiol levels in
obese and nonobese children are consistent with the increased bone maturation of
the obese children. Estradiol did not correlate significantly with DEXA fat mass,
body mass index, or arm fat measures of adiposity. Obese children had higher 24-h
mean leptin concentrations than nonobese children (28.6+/-17.4 vs. 6.8+/-7.1
ng/mL; P < 0.001). Leptin concentrations positively correlated with DEXA fat
mass, body mass index, and arm fat measurement of adiposity. Girls had higher 24
h mean leptin levels than boys when controlling for adiposity. Estradiol and
leptin concentrations fluctuated over a 24-h period in both groups, with all
children having higher leptin concentrations at night and higher estradiol
concentrations in the morning. This diurnal rhythm was of a similar pattern, but
at higher levels for leptin and lower levels for estradiol in the obese children
compared to nonobese children. There was no significant correlation between
estradiol and leptin levels. Bone mineral density, as measured by DEXA, did not
differ between obese and nonobese children. Similar bone mineral density values
in obese and nonobese children are consistent with the increased bone maturation
of the obese children. Bone mineral density was not correlated with estradiol or
leptin level in these children. In conclusion, obese children had similar
estradiol levels and equivalent bone ages at a younger chronological age than
nonobese children. Leptin was higher in these obese children, but did not
correlate with estradiol level or bone age. These findings suggest that the role
of leptin in both obesity and pubertal development is not directly correlated
with the estradiol level.
PMID- 9768649
TI - Effect of growth hormone (GH) on serum concentrations of leptin: study in
patients with acromegaly and GH deficiency.
AB - As leptin, an ob gene product, plays a pivotal role in the regulation of
adiposity and energy homeostasis, the level of its expression is likely to
fluctuate under various physiological, nutritional, and disease conditions.
Reports regarding the effect of GH on serum leptin levels are inconsistent. We
have measured serum leptin levels and correlated them with several variables in
patients with acromegaly, patients with adult GH deficiency (GHD), and normal
controls. In 116 normal subjects, the mean serum concentration of leptin was
5.0+/-2.8 (mean +/- SD) ng/mL in men (n = 42) and 10.7+/-7.3 ng/mL in women (n =
73), respectively. As reported previously, the leptin levels in women were
significantly (P < 0.001) higher than in men, and there was a strong positive
correlation between log-transformed serum leptin levels and percent body fat in
simple regression analysis (in men: r = 0.606; P < 0.0001; in women: r = 0.707; P
< 0.0001). In 36 acromegalic patients, the percent body fat mass was
significantly lower than that in normal subjects, and the mean serum leptin level
was 2.2+/-1.8 ng/mL in men (n = 18) and 3.6+/-2.5 ng/mL in women (n = 18).
Analysis of covariance revealed that serum leptin levels in acromegalics were
significantly lower than those in normal subjects after correcting percent body
fat (P = 0.016 for men and P < 0001 for women). In male patients with GHD (n =
20), the mean percent body fat was significantly (P < 0.05) higher than that in
age-matched controls, whereas the value in female GHD patients (n = 15) did not
differ from that in age-matched controls. Serum leptin levels in GHD patients
were 5.1+/-2.5 ng/mL in men and 11.5+/-8.1 ng/mL in women, which were not
different from those in normal subjects adjusted for percent body fat mass. In
multiple regression analysis models with log-transformed leptin as the dependent
variable, gender, percent body fat (or body fat mass), and serum insulin-like
growth factor I levels entered the equations at a statistically significant
level. These data suggest that excess GH/insulin-like growth factor I reduces
serum leptin levels by reducing body fat mass and/or by unknown mechanisms.
PMID- 9768650
TI - A randomized, cross-over trial of once-daily versus twice-daily parathyroid
hormone 1-34 in treatment of hypoparathyroidism.
AB - Once-daily sc injection of PTH 1-34 can normalize mean serum and urine calcium
levels in patients with hypoparathyroidism; however, once-daily PTH has
diminishing effects on serum calcium after 12 h, such that serum calcium levels
fall below the normal range in some patients. Once-daily PTH also causes a marked
increase in bone turnover, with persistent increases in markers of bone formation
and resorption. To test the hypothesis that a twice-daily PTH regimen can produce
more physiological control than a once-daily regimen, we performed a randomized
cross-over trial, lasting 28 weeks, in 17 adult subjects with hypoparathyroidism.
Each 14-week study arm was divided into a 2-week inpatient dose-adjustment phase
and a 12-week outpatient phase. The PTH dose (given sc once daily at 0900 h or
twice daily with one dose at 0900 h and the other at 2100 h) was adjusted to
maintain both serum and urine calcium within, or close to, the normal range.
During the second half of the day (12-24 h), twice-daily PTH increased serum
calcium and magnesium levels more effectively than once-daily PTH. In patients
with calcium receptor mutations (CaR), once-daily PTH normalized urine calcium,
provided that serum calcium was maintained at levels below normal range. However,
twice-daily PTH treatment produced higher mean serum calcium in patients with CaR
with no significant rise in urine calcium excretion, and with no significant
differences in either serum or urine calcium levels between CaR and patients with
acquired or idiopathic hypoparathyroidism. Thus, treatment with twice-daily PTH
is the better regimen for patients with CaR to overcome their tendency to
hypercalciuria while producing near-normal levels of serum calcium. The total
daily PTH dose was markedly reduced with the twice-daily regimen (twice daily
46+/-52 vs. once daily 97+/-60 microg/day, P < 0.001). We conclude that a twice
daily PTH regimen provides effective treatment of hypoparathyroidism and reduces
the variation in serum calcium levels at a lower total daily PTH dose.
PMID- 9768651
TI - A prospective study on cortisol, dehydroepiandrosterone sulfate, and cognitive
function in the elderly.
AB - The objective of this study was to investigate the relation between the
peripheral concentrations of the adrenal steroid hormones cortisol and
dehydroepiandrosterone sulfate (DHEAS) and cognitive impairment and decline. A
prospective study design was used. The setting was a suburb of Rotterdam, The
Netherlands. The study population consisted of a sample of 189 healthy
participants from the population-based Rotterdam Study, aged 55-80 yr, who were
invited for an additional examination. Follow-up examinations took place 1.9 yr
after baseline, on the average. We determined fasting blood levels of DHEAS
before dexamethasone administration and of cortisol and corticosteroid-binding
globulin before and after the administration of 1 mg dexamethasone overnight. The
30-point Mini-Mental State Examination (MMSE) was used to assess cognition. The
associations with cognitive impairment (MMSE score of <26; 6% of the sample) and
cognitive decline (drop in MMSE score of >1 point/yr; 24%) were estimated using
logistic regression, with adjustment for age, sex, education, and depressive
symptoms. An increase of 1 SD in the estimate of free cortisol (SD = 30.3) was
associated with cognitive impairment, although not significantly [odds ratio (OR)
= 1.5; 95% confidence interval (CI), 0.9-2.4]. A 1 SD increase in the natural
logarithm of cortisol after the administration of 1 mg dexamethasone (SD = 0.68)
was associated with an OR for cognitive decline of 1.5 (95% CI, 1.0-2.3). A 1 SD
increase in DHEAS (SD = 2.10 micromol/L) was inversely, but nonsignificantly,
related to cognitive impairment (OR = 0.5; 95% CI, 0.2-1.1) and cognitive decline
(OR = 0.6; 95% CI, 0.4-1.1). The ratio of free cortisol over DHEAS was
significantly related to cognitive impairment (OR = 1.8; 95% CI, 1.0-3.2). This
prospective study among healthy elderly subjects suggested that basal free
cortisol levels were positively related to cognitive impairment, and cortisol
levels after dexamethasone treatment were related to cognitive decline. There was
an inverse, but nonsignificant, association between DHEAS and cognitive
impairment and decline.
PMID- 9768652
TI - Changes in thyroid hormone levels during growth hormone therapy in initially
euthyroid patients: lack of need for thyroxine supplementation.
AB - The occurrence of central hypothyroidism in previously euthyroid children during
GH therapy has been reported with widely varying incidence. We monitored the
acute effects on the hypothalamic-pituitary-thyroid axis in 15 euthyroid children
with classic GH deficiency during the first year of GH therapy. All were
initially euthyroid, as assessed by normal baseline TSH, T4, free T4, and T3
levels and negative antithyroid antibodies. A thyroid profile (T4, free T4 index,
T3, rT3, and TSH) was performed at baseline and 1, 3, 6, 9, and 12-15 months
after GH therapy began; a TRH stimulation test was performed at baseline and
after 1, 3, and 9 months of therapy. By 1 month, there were significant decreases
in T4, free T4 index, and rT3, and significant increases in T3 and the T3/T4
ratio. The changes from baseline values were greatest at 1 month, were almost
universal for all thyroid values, and showed a gradual return to baseline from 3
12 months. There were no clinical signs of hypothyroidism and no change in
baseline or TRH-stimulated TSH levels or in cholesterol levels, and all patients
grew at velocities expected for the treatment schedule. There is little evidence
for the development of clinically significant hypothyroidism in the great
majority of initially euthyroid patients after GH therapy is begun. T4
supplementation is seldom needed in such patients.
PMID- 9768653
TI - Can weight gain in healthy, nonobese volunteers be predicted by differences in
baseline plasma insulin concentration?
AB - In this study, we have evaluated the effect, over approximately 14 yr, of
differences in baseline degree of hyperinsulinemia on weight gain in 647 healthy,
nonobese factory workers. The subjects were divided into 4 quartiles, on the
basis of their plasma insulin response to an oral glucose challenge, in 1981. At
that time, the mean (+/-SD) plasma insulin concentration, 2 h after the glucose
challenge, varied from 18+/-5 to 106+/-42 microU/mL. Despite this approximate 6
fold difference in plasma insulin response at baseline, the weight gain over the
period of observation was similar in all quartiles, with mean (+/-SD) increments
(kg) of 1.8+/-5.1, 1.6+/-5.3, 2.3+/-5.2, and 2.3+/-5.7, going from the lowest
quartile to the highest quartile, in terms of insulin concentration. Furthermore,
when the population was considered as a whole, there was no correlation between
baseline degree of hyperinsulinemia and change in either absolute (r = 0.004) or
percent (r = 0.003) weight gain. Finally, there was no difference in the number
of individuals who gained more than 4.5 kg, as a function of their baseline
insulin response. Consequently, we conclude that 6-fold differences in plasma
insulin responses to glucose do not predict weight gain in a healthy, nonobese
population.
PMID- 9768654
TI - In pubertal girls, naloxone fails to reverse the suppression of luteinizing
hormone secretion by estradiol.
AB - Estradiol (E2) negative feedback on LH secretion was examined in 10 pubertal
girls, testing the hypothesis that E2 suppresses LH pulse frequency and amplitude
through opioid pathways. At 1000 h, a 32-h saline infusion was given, followed 1
week later by an E2 infusion at 13.8 nmol/m2 x h. During both infusions, four iv
boluses of saline were given hourly beginning at 1200 h, and four naloxone iv
boluses (0.1 mg/kg each) were given hourly beginning at 1200 h on the following
day. Blood was obtained every 15 min for LH determination and every 60 min for E2
determination from 1200 h to the end of the infusion. E2 infusion increased the
mean serum E2 concentration from 44+/-17 to 112+/-26 pmol/L (P < 0.01). The mean
LH concentration between 2200-1200 h decreased from 3.19+/-0.89 to 1.99+/-0.65
IU/L (P = 0.014), and LH pulse amplitude decreased from 3.4+/-0.6 to 2.6+/-0.5
IU/L (P = 0.0076). Although there were 1.2 fewer pulses during E2 infusion
compared to saline infusion, differences did not reach significance (P = 0.1; 95%
confidence interval for the difference, -3.5, 1.1). Pituitary responsiveness to
GnRH, assessed at the end of the infusion by administering 250 ng/kg GnRH iv, did
not change during E2 infusion. The effect of naloxone blockade of opioid activity
on LH secretion was determined by assessing the area under the curve (AUC) from
1200-1600 h. During saline infusion, the LH AUC was 1122+/-375 IU/L during saline
boluses and 1575+/-403 IU/L during naloxone boluses (P = 0.39). When E2 was
infused, the LH AUCs during saline and naloxone boluses were 865+/-249 and 866+/
250 IU/L, respectively. Thus, in pubertal girls: 1) E2 decreases the LH
concentration and LH pulse amplitude; 2) the main site of negative feedback
effect of E2 appears to be at the level of the hypothalamus; 3) an increase in LH
secretion after naloxone administration could not be demonstrated in these girls
and may depend on the maturity of the hypothalamic-pituitary-gonadal axis; and 4)
opioid receptor blockade does not reverse the E2 inhibition of LH secretion even
in the most mature girls. Thus, E2 suppression of LH secretion in pubertal girls
appears to be mediated by a decrease in hypothalamic GnRH secretion that is
independent of opioid pathways.
PMID- 9768655
TI - Levels of adrenocortical autoantibodies correlate with the degree of adrenal
dysfunction in subjects with preclinical Addison's disease.
AB - To test the hypothesis that levels of adrenal autoantibodies correlate with the
degree of adrenal dysfunction, we followed up adrenal cortex autoantibody (ACA)
titers and 21-hydroxylase (21OH) autoantibody (21OHAb) levels in 19 ACA-positive
subjects with preclinical Addison's disease. On enrollment, all the 19 ACA
positive subjects were positive for 21OHAb. At follow-up, the concordance rate
for simultaneous presence/absence of both ACA and 21OHAb was as high as 91% and a
strong, positive correlation between 21OHAb levels and ACA titers was observed (P
< 0.0001). The levels of adrenal autoantibodies were positively associated with
the severity of adrenal dysfunction (ANOVA, P < 0.0001 for both 21OHAb and ACA):
the 21OH index was significantly lower at stage 0 or 1 than at stage 2+3
(corrected P < 0.001 andP < 0.05) or stage 4 (corrected P < 0.001 and <0.01).
Similarly, ACA titer at stage 4 was significantly higher than stage 0 (P <
0.001), stage 1 (P < 0.001), and stage 2+3 (P < 0.05); and ACA titer at stage 2+3
was higher than stage 0 (P < 0.001) and stage 1 (P < 0.05). In subjects with
progression of adrenal dysfunction (n = 14), levels of 21OHAb and ACA increased
significantly (P = 0.041 and P = 0.002) during the follow-up period. In 5
subjects, the remission of biochemical signs of adrenal dysfunction was
associated with the disappearance of both ACA and 21OHAb. Our study shows that
the levels of adrenal autoantibodies correlate with the degree of adrenal
dysfunction, and this suggests that production of high-level 21OHAb strongly
signals the destructive phase of the autoimmune disease process.
PMID- 9768656
TI - Human growth hormone treatment of short-stature children born small for
gestational age: effect on muscle and adipose tissue mass during a 3-year
treatment period and after 1 year's withdrawal.
AB - In addition to its growth promoting effect, GH has profound metabolic effects
that have not always been evaluated in longitudinal studies. We have recently
shown that the effect of GH on body composition can be evaluated by magnetic
resonance imaging measurement of adipose and muscle tissue cross-sectional (cs)
areas in the thigh. The aim of this study was to evaluate the long-term effects
of human GH (hGH) (0.2 IU/kg day) on muscle and adipose tissue mass during a 3-yr
treatment period and after 1 year's withdrawal in short SGA (small for
gestational age) children. Measurement of muscle and fat tissue mass by magnetic
resonance imaging of the thighs was used to study the metabolic effect of hGH in
14 prepubertal short children born SGA. Results were compared with those of a
control group of 7 normal children followed longitudinally. An increase of muscle
tissue cs area was observed during the 3 yr of hGH treatment, an increase which
was significantly different during the first 2 yr of treatment from that seen in
controls (+31.2+/-2.6% and +18.1+/-1.8% during the 1st and 2nd year,
respectively, vs. +9.1+/-2.6% change during 1 yr in controls). After a
significant decrease in adipose tissue cs area during the first year of therapy (
16.4+/-3.4% vs. baseline values), an increase in adipose tissue cs area occurred
during the second and third years. At the end of the third year, the muscle
tissue cs area change was significantly greater in SGA-treated children, as
compared with controls (+71.6+/-4.6% vs. 22.1+/-4.6%; P < 0.001), whereas the
adipose tissue cs area change was similar in the two groups (+12.6+/-9.5% vs.
+19.9+/-4.2%). After hGH withdrawal, the effects were opposite after 3 months, as
compared with those observed after the first 3 months of hGH administration,
whereas no additional significant change was seen after 1 yr off treatment,
indicating the maintenance of muscle and adipose tissue mass. In conclusion, hGH
administered to SGA children is effective in improving growth velocity and has
long-term effects on muscle and adipose tissue mass. These effects may lead to
speculation about the sensitivity of these tissues to GH. The physiological
consequences of such effects must be evaluated.
PMID- 9768657
TI - Rapid cardiovascular action of aldosterone in man.
AB - Rapid nongenomic in vitro effects of aldosterone have been demonstrated recently
in cultured vascular smooth muscle and endothelial cells. But there is, as yet,
little evidence for corresponding in vivo effects. The present study thus
investigates the rapid nongenomic effects of aldosterone on human cardiovascular
function. In a double-blind placebo-controlled randomized parallel trial on 17
patients with suspected coronary heart disease, the effect of 1 mg aldosterone iv
on cardiovascular function was assessed during cardiac catheterization.
Hemodynamic parameters (such as heart rate, left ventricular and atrial
pressures, arterial pressures, vascular resistances, and cardiac output) were
measured before and 3 and 10 min after administration of aldosterone or placebo.
Significant changes were found for systemic vascular resistance, cardiac output,
and cardiac index, compared with the placebo group (Wilcoxon test, P < 0.02
0.05). The effect of aldosterone dissipated within 10 min. The results are in
line with the in vitro data cited above and consistent with earlier findings on
acute cardiovascular effects of aldosterone, which have now been confirmed and
extended by contemporary techniques. The hypotheses of rapid nongenomic in vivo
effects of aldosterone are further substantiated by this study.
PMID- 9768658
TI - A reliable endocrine test with human menopausal gonadotropins for diagnosis of
true hermaphroditism in early infancy.
AB - In true hermaphroditism diverse phenotypes and karyotypes are found; there are no
distinctive laboratory features that can distinguish it from other intersex
disorders, thus the diagnosis is made by the histological findings. Existence of
Leydig cells is demonstrated by testosterone levels above the female range;
however, presence of ovarian tissue cannot be ascertained because of the absence
of a reliable functional test. Unless appropriate biopsies are performed or the
whole gonad is removed, there is a risk of not diagnosing true hermaphroditism.
To find a reliable test that can differentiate patients with true hermaphroditism
from those with other intersex disorders, we investigated the estradiol (E2)
response to human menopausal gonadotropins (hMG) in infants with genital
ambiguity. These results were correlated with the histological findings. Eleven
infants with genital ambiguity and four with a high scrotal testis were
stimulated every 12 h with 2 IU/kg hMG. If E2 rose above 80 pg/mL (cut-off
point), the test was discontinued; if after 7 days E2 remained below 80 pg/mL,
the hMG dose was doubled and stimulation extended for 7 additional days. In five
patients in whom true hermaphroditism was later histologically demonstrated, E2
rose above 80 pg/mL. In two of them, ovarian tissue was removed and hMG
stimulation repeated; no response above our cut-off point was observed during the
second test. The maximal E2 response to hMG in the remaining 10 individuals was
43 pg/mL; after laparotomy or gonadal biopsies no ovarian tissue was found. The
hMG stimulation test can be considered a reliable and safe dynamic procedure for
demonstrating the presence or absence of ovarian tissue in infants with genital
ambiguity.
PMID- 9768659
TI - Suppression of spermatogenesis in man induced by Nal-Glu gonadotropin releasing
hormone antagonist and testosterone enanthate (TE) is maintained by TE alone.
AB - GnRH antagonists plus testosterone (T) suppress LH and FSH levels and inhibit
spermatogenesis to azoospermia or severe oligozoospermia. High-dose T treatment
alone has been shown to be an effective male contraceptive (contraceptive
efficacy rate of 1.4 per 100 person yr). Combined GnRH antagonist and T induces
azoospermia more rapidly and at a higher incidence than T alone; this combination
has therefore been proposed as a prototype male contraceptive. However, because
GnRH antagonists are expensive to synthesize and difficult to deliver, it would
be desirable to rapidly suppress sperm counts to low levels with GnRH antagonist
plus T and maintain azoospermia or severe oligozoospermia with T alone. In this
study, 15 healthy men (age 21-41 yr) with normal semen analyses were treated with
T enanthate (TE) 100 mg im/week plus 10 mg Nal-Glu GnRH antagonist sc daily for
12 weeks to induce azoospermia or severe oligozoospermia. At 12-16 weeks, 10 of
15 subjects had zero sperm counts, and 14 of 15 had sperm counts less than 3 x
10(6)/mL. The 14 who were suppressed on combined treatment were maintained on TE
alone (100 mg/week im) for an additional 20 weeks. Thirteen of 14 subjects in the
TE alone phase had sperm counts maintained at less than 3 x 10(6)/mL for 20
weeks. Ten remained persistently azoospermic or had sperm concentration of 0.1 x
10(6)/mL once during maintenance. Mean LH and FSH levels in the subjects were
suppressed to 0.4+/-0.2 IU/L and 0.5+/-0.2 IU/L in the induction phase, which was
maintained in the maintenance phase. The 1 subject who failed to suppress sperm
counts during induction had serum LH and FSH reduced to 0.3 and 0.5 IU/L,
respectively. The subject who failed to maintenance had LH and FSH suppressed to
1.0 and 0.2 IU/L, respectively, during the induction phase but these rose to 1.6
and 2.1 IU/L, respectively, during maintenance. Failure to suppress or maintain
low sperm counts may be related to incomplete suppression of serum LH and FSH
levels. We conclude that sperm counts suppressed with GnRH antagonist plus T can
be maintained with relatively low dose TE treatment alone. This concept should be
explored further in the development of effective, safe, and affordable hormonal
male contraceptives.
PMID- 9768660
TI - Short stature associated with high circulating insulin-like growth factor (IGF)
binding protein-1 and low circulating IGF-II: effect of growth hormone therapy.
AB - We report a case of short stature associated with high circulating levels of
insulin-like growth factor (IGF)-binding protein-1 (IGFBP-10 and low levels of
IGF-II responsive to pharmacological treatment with GH. Our patient suffered
severe growth failure from birth (2.06 SD below the mean for normal full-term
boys, and 5.2 and 7.3 SD below the mean at 5 and 10 months). Studies carried out
before referral to our pediatric unit included normal 46,XY karyotype and normal
encephalic imaging. Other endocrine and metabolic alterations and other systemic
diseases were excluded. At 1.7 yr of age (length, 6.1 SD; weight, 4.6 SD; head
circumference, 1.4 SD below the mean, respectively) the patient was referred to
our pediatric unit. The baseline GH concentration was 31 microg/L, and the peak
after an arginine load was 59.6 microg/L. In the same samples GH bioactivity was
nearly superimposable (RIA/Nb2 bioactivity ratio = 0.9). Fasting insulin and
glucose concentrations were 7.4 microU/mL and 65 mg/dL, respectively, both
normally responsive to an oral glucose load. GH insensitivity was excluded by a
basal IGF-I concentration (64 ng/mL) in the normal range for 0- to 5-yr-old boys
and its increase after 2 IU/day hGH administration for 4 days. IGFBP-3 (0.5
microg/mL) was slightly reduced, whereas IGFBP-1 (2218 and 1515 ng/mL in two
different basal samples) was well above the normal values for age and was
suppressible by GH (maximum suppression, -77% at 84 h) and glucose load (maximum
suppression, -46% at 150 min). The basal IGF-II concentration was below the
normal range (86 ng/mL), whereas IGFBP-2 was normal (258 ng/mL). Analysis of the
promoter region of IGFBP-1 and IGF-II failed to find major alterations. Neutral
gel filtration of serum showed that almost all IGF-I activity was in the 35- to
45-kDa complex, coincident with IGFBP-1 peak, while the 150-kDa complex was
absent, although the acid-labile subunit was normally represented. At 2.86 yr
(height, 65.8 cm; height SD score, -7.3; height velocity SD score, -5) the
patient underwent treatment with 7 IU/week human GH; after 4 months, the
patient's height was 68.5 cm (height SD score, -6.9) corresponding to a growth
velocity of 8.3 cm/yr (0.3 height velocity SD score). IGFBP-1 was reduced (216
ng/mL), although still in the high range, whereas IGF-I (71 ng/mL), IGFBP-3 (0.62
microg/mL), and IGF-II (111 ng/mL) were only slightly increased. The IGF-I
profile showed activity in the 150-kDa region. In conclusion, we speculate that
the increased IGFBP-1 values found in this patient produce 1) inhibition of IGF-I
biological activity and, therefore, a resistance to IGF-I not due to a receptor
defect for this hormone; 2) inhibition of formation of the circulating 150-kDa
ternary complex and, therefore, an accelerated clearance rate of IGF peptides; 3)
inhibition of the feedback action on GH, leading to increased GH levels, which
could suggest the diagnosis of GH insensitivity syndrome; and 4) inhibition of
body growth.
PMID- 9768661
TI - Emergency and prolonged use of intravenous etomidate to control hypercortisolemia
in a patient with Cushing's syndrome and peritonitis.
AB - We report the emergency and prolonged use of etomidate to control circulating
cortisol levels in a patient with Cushing's syndrome secondary to ectopic ACTH
production from a pancreatic islet cell tumor. Duodenal perforation and
peritonitis complicated an episode of salmonella septicemia, precluding the use
of conventional oral medical adrenolytic therapy. Endogenous cortisol secretion
was abolished by parenteral etomidate, allowing serum cortisol levels to be
controlled with an iv infusion of hydrocortisone over an 8-week period in
intensive care before definitive pancreatic surgery.
PMID- 9768662
TI - Circulating iodide concentrations during and after pregnancy.
AB - Early, indirect studies suggested that an important aspect of thyroid economy
during pregnancy was a decline in plasma or serum inorganic iodide (PII)
concentrations, but there is little information concerning circulating iodide
concentrations as assessed by direct measurement. The present study was
undertaken to determine the relationship between gestation and serum iodide
concentrations as assessed by direct measurement of PII. PII concentrations,
urinary iodide levels, and other parameters of thyroid economy were measured
during the first, second, and third trimesters and after delivery in 16 women.
Mean serum T4 concentrations were significantly higher in all 3 trimesters than
those after delivery. Serum free T4 index concentrations were significantly
higher in the first trimester than during later periods of gestation or after
delivery, but serum TSH concentrations were not depressed in the first trimester.
Serum thyroglobulin concentrations were similar during pregnancy and after
delivery. There was wide variability in PII and urinary iodide concentrations
during and after pregnancy, but there was no trend for PII concentrations to be
depressed during pregnancy. Pregnancy, at least in iodine-sufficient regions,
does not have an important influence on circulating concentrations of iodide.
PMID- 9768663
TI - Insulin, insulin-like growth factor I (IGF-I), IGF-binding protein-1, growth
hormone, and feeding in the newborn.
AB - The relationship between GH, insulin-like growth factor I (IGF-I), IGF-binding
protein-1 (IGFBP-1), and insulin may be critical to the understanding of
variation in early growth, especially in the small for gestational age (SGA)
baby. To investigate these relationships, we have undertaken 12-h hormone
profiles in 26 babies (13 SGA) at a median of 4.5 days of age. GH levels were
measured every 10 min; insulin and IGFBP-1 were measured every 20 min. Mean
levels of these hormones and IGF-I levels (from a single sample) were related to
size at birth. The GH data were analyzed by Pulsar and time series analysis to
characterize hormone pulsatility and relationship with feeds. IGF-I levels
correlated with birth weight and length (r2 = 0.47; P = 0.004, and r2 = 0.5; P =
0.0005, respectively, after allowing for gestation), whereas mean GH levels were
negatively related to birth size (r2 = -0.18; P = 0.04 and r2 = -0.2; P = 0.03
for weight and length, respectively). No direct relationship between mean GH
levels and IGF-I was identified. IGF-I levels were higher in appropriate for
gestational age (AGA; mean +/- SD, 82+/-61 ng/mL) than in SGA (34+/-22 ng/mL; P =
0.03) babies. Baseline (mean +/- SD, 25.9+/-11.9), mean (33.9+/-14.0), and peak
(45.0+/-18.1 microg/L) GH levels were higher in SGA than in AGA babies [17.1+/
8.2 (P = 0.04), 22.5+/-10.4 (P = 0.03), and 30.7+/-15.4 microg/L (P = 0.04),
respectively]. Mean IGFBP-1 levels were also higher in SGA than AGA babies
(157.4+/-90.7 vs. 62.7+/-43.8 ng/mL; P = 0.01). A positive correlation was
identified between changes in insulin and coincident pulses of GH (r = 0.147; P <
0.01), whereas there was an inverse relationship between insulin and IGFBP-1,
with a lag time 120 min (r = -0.33; P < 0.0001). In conclusion, these studies
indicate that the GH-IGF-I axis is closely related to feeding in the newborn. In
SGA babies, low IGF-I and elevated IGFBP-1 reflect the slow growth, but elevated
GH and rapid GH pulsatility may be a signal for lipolysis.
PMID- 9768664
TI - Precocious pubarche, hyperinsulinism, and ovarian hyperandrogenism in girls:
relation to reduced fetal growth.
AB - Pronounced adrenarche with precocious pubarche (PP) in girls has been associated
with hyperinsulinism and subsequent functional ovarian hyperandrogenism (FOH).
Recently, pronounced adrenarche and insulin resistance have each been related to
low birth weight. We have now tested the hypothesis that the frequent concurrence
of PP with pronounced adrenarche, FOH, and hyperinsulinemia in girls may be
secondary to separate relationships between these conditions and low birth
weight. A total of 185 girls (aged 5-18 yr) without endocrinopathy or with PP and
pronounced adrenarche with or without FOH were studied; mean serum insulin (MSI)
concentrations were determined after a standardized oral glucose tolerance test.
Birth weight SD scores [mean (SEM)] of control girls (0.38+/-0.08; n = 83) were
higher (P < 0.0001) than those of PP girls (-0.81+/-0.13; n = 102). Among
postmenarcheal PP girls, birth weight SD scores of girls without FOH (-0.25+/
0.19; n = 25) were higher (P < 0.0001) than those in girls with FOH (-1.51+/
0.28; n = 23). In pubertal girls (n = 145), MSI levels correlated negatively with
birth weight SD scores (r = -0.48; P < 0.05), independently of PP. MSI levels in
girls with birth weight below 1 SD (93+/-9 mU/L; n = 33) were higher (P < 0.0001)
than those in girls with birth weight between -1 and +1 SD (52+/-2 mU/L; n = 94),
whereas glycemia profiles were comparable. Integration of the aforementioned data
suggests that there may be a sequence in the associations between reduced fetal
growth and components of the postnatal endocrine system; minor fetal growth
reduction appears to be associated with amplified adrenarche, whereas more
pronounced prenatal growth restriction seem to precede FOH and hyperinsulinemia
during adolescence. In conclusion, these findings corroborate the hypothesis that
the frequent concurrence of PP (with pronounced adrenarche), FOH, and
hyperinsulinemia in girls may result from a common early origin (low birth weight
serving as a marker), rather than from a direct interrelationship later in life.
PMID- 9768665
TI - Interactive effect of estradiol and vitamin D receptor gene polymorphisms as a
possible determinant of growth in male and female infants.
AB - An association between vitamin D receptor (VDR) gene polymorphism and body size
has been observed in infants. We hypothesized that the estradiol receptor (ER)
gene is another determinant of infant growth and that the effects of the VDR and
ER genotypes may interact with each other. The ER genotype (PvuII and XbaI
sites), VDR genotype (BsmI site), and body size during the first 2 yr of life
were analyzed in 161 healthy Caucasian full-term babies homozygous for the BsmI
polymorphism of the VDR gene (BB or bb). There was no significant association
between ER polymorphism and 1) body weight in boys and girls, 2) body length in
girls, or 3) body length in boys with a bb genotype. In contrast, ER polymorphism
and body length were significantly associated in BB boys. Boys with the BBpp
genotype were shorter at birth (P < 0.005) and at 10 months of age (P < 0.001)
than boys with other genotypes. They were even shorter than girls with the same
genotype. These results indicate some degree of interaction between the effects
of the VDR and ER genes, leading to significant variations in body growth during
infancy, especially in boys.
PMID- 9768666
TI - A progesterone-induced endometrial homolog of a new candidate tumor suppressor,
DMBT1.
AB - We have previously prepared and characterized a subtracted library enriched for
endometrial progesterone (P)-dependent genes in the rhesus monkey. One of the
fragment clones (H3) that we selected for sequencing from this library was found
to be homologous to human DMBT1, a recently isolated member of the scavenger
receptor cysteine-rich superfamily and a new putative tumor suppressor. In this
report, we provide evidence that H3 is the rhesus monkey homolog of DMBT1.
Additional sequence data of H3 (1071 bp) showed a striking homology with DMBT1
(92% identical). Semiquantitative kinetic PCR of estrogen-dominant vs. P-dominant
endometrial complementary DNA populations showed that the H3 gene was up
regulated 5-fold by normal secretory P levels. In situ hybridization with unique
probes to H3 confirmed the up-regulation by P in the endometrium and a restricted
expression in the stromal compartment. Another recent report suggested the
presence of an endometrial tumor suppressor in the same chromosomal region as
DMBT1 (10q23-26); deletions in this region were associated with endometrial
cancers. Together, these studies potentially provide a molecular link to the
protective effect of the action of P on unopposed estrogen exposure in
reproductive tract cancers in women.
PMID- 9768667
TI - Serum leptin concentrations in Caucasian and African-American girls.
AB - Because African-American girls are heavier, taller, and mature earlier than
Caucasian girls, we hypothesized that the serum leptin concentration differs
between the two groups. Serum leptin concentrations were measured by immunoassay
in 12-h fasted blood samples collected from 79 Caucasian and 57 African-American
girls between 8 and 17 yr of age. Body composition was measured by dual-energy x
ray absorptiometry, sexual maturity by physical examination, and physical fitness
by treadmill testing. Serum leptin concentrations were positively correlated (P <
0.01) with maturation, body fatness, and insulin and were higher (6.6 ng/mL, P <
0.01) in the African-American girls after adjusting for age. The difference
remained significant (P < 0.01) but was reduced to 3.2 ng/mL after controlling
for differences in maturation, fat mass, and physical fitness. The higher serum
leptin levels might play an important role in the accelerated growth and sexual
maturation of African-American girls.
PMID- 9768668
TI - Secretory mechanisms of growth hormone (GH)-releasing peptide-, GH-releasing
hormone-, and thyrotropin-releasing hormone-induced GH release in patients with
acromegaly.
AB - The GH secretory mechanism of GH-releasing hexapeptide (GHRP-6), GHRH, and TRH
were studied in vivo and in vitro in seven patients with acromegaly. In an in
vivo study, these patients showed clear GH responses to single administration of
GHRP (four of four patients), GHRH (seven of seven patients), and TRH (seven of
seven patients) and enhanced responses to GHRP plus GHRH (two of four patients)
or TRH plus GHRH (six of six patients). In an in vitro dispersed cell study, the
majority of patients examined also showed clear GH responses to GHRP (four of
four patients), GHRH (six of six patients), and TRH (four of four patients) and
an enhanced response to GHRP plus GHRH (three of three patients) or TRH plus GHRH
(three of four patients). In one patient (no. 3), GHRP plus forskolin (adenylate
cyclase activator), but not GHRP plus phorbol 12-myristate 13-acetate (protein
kinase C activator), additively enhanced the GH response. Nordihydroguaiaretic
acid (NDGA; inhibitor of arachidonic cascade) inhibited GH release induced by
GHRP, TRH, GHRH, TRH plus GHRH, or GHRP plus GHRH, but did not inhibit basal GH
secretion. In contrast, NDGA distinctly elevated intracellular cAMP levels in
another patient (no. 7) when coadministered with GHRP, GHRH, or GHRP plus GHRH,
whereas cAMP levels were not modified by single administration of GHRP and NDGA.
The GH response to the combined administration of GHRP and GHRH was synergistic
in this patient, but was additive in the other two patients. It is concluded that
GHRP, TRH, and GHRH directly stimulate in vivo and in vitro GH release from human
somatotropinomas, and GHRP and TRH mainly exert their action through activation
of the phosphatidylinositol-protein kinase C pathway, whereas GHRH exerts its
action through the adenylate cyclase-protein kinase A pathway. These three agents
seem to release GH via the arachidonic cascade.
PMID- 9768669
TI - Collagen cross-link excretion during space flight and bed rest.
AB - Extended exposure to weightlessness results in bone loss. However, little
information exists as to the precise nature or time course of this bone loss.
Bone resorption results in the release of collagen breakdown products, including
N-telopeptide and the pyridinium (PYD) cross-links, pyridinoline and
deoxypyridinoline. Urinary pyridinoline and deoxypyridinoline are known to
increase during bed rest. We assessed excretion of PYD cross-links and N
telopeptide before, during, and after long (28-day, 59-day, and 84-day) Skylab
missions, as well as during short (14-day) and long (119-day) bed-rest studies.
During space flight, the urinary cross-link excretion level was twice those
observed before flight. Urinary excretion levels of the collagen breakdown
products were also 40-50% higher, during short and long bed rest, than before.
These results clearly show that the changes in bone metabolism associated with
space flight involve increased resorption. The rate of response (i.e. within days
to weeks) suggests that alterations in bone metabolism are an early effect of
weightlessness. These studies are important for a better understanding of bone
metabolism in space crews and in those who are bedridden.
PMID- 9768670
TI - Exclusion of the adrenocorticotropin (ACTH) receptor (MC2R) locus in some
families with ACTH resistance but no mutations of the MC2R coding sequence
(familial glucocorticoid deficiency type 2).
AB - Several mutations in the coding exon of the ACTH receptor (MC2R) gene have been
reported in cases of familial glucocorticoid deficiency or FGD. However, many
patients with a similar syndrome do not present any mutation in the coding region
of this gene. This is the case in 11 families we have investigated. Patients in
these families present the typical clinical features of FGD, but no mutation was
found in the coding exon of the ACTH receptor. To determine whether mutations on
MC2R gene, but outside the coding region, may be involved in FGD in these
families, we have performed a linkage analysis. Using three markers flanking MC2R
gene on chromosome 18, we were able to exclude linkage in a region of 12
centimorgans around the gene. This result clearly indicates that FGD is
genetically heterogeneous. Defects in gene(s) different from MC2R gene are
implicated in this syndrome.
PMID- 9768671
TI - Trafficking of androgen receptor mutants fused to green fluorescent protein: a
new investigation of partial androgen insensitivity syndrome.
AB - The naturally occurring mutations of the androgen receptor (AR), detected in
patients with androgen insensitivity syndrome (AIS), are currently analyzed by in
vitro assays. Unfortunately, these assays do not always permit the demonstration
of a direct relationship between the in vitro activity of the receptor and the
severity of the phenotype (in particular, for mutations detected in patients with
partial AIS). We recently studied the trafficking of wild-type AR, fused to the
green fluorescent protein (GFP) in living cells. In the present study, we applied
this method for the analysis of AR mutants to find out whether it could be a
complementary method of investigation of AIS. After construction of the GFP-AR
mutant fusion proteins, the androgen-binding characteristics, nuclear transfer
capacities, and transcriptional activities were evaluated. The nuclear transfer
was quantified in the presence of various concentrations of dihydrotestosterone
(DHT). We studied two mutants associated with partial AIS: G743V and R840C. The
androgen-binding characteristics of both mutants were affected, in comparison
with normal AR. Although the affinities were similar, the dissociation rate of
GFP-AR-G743V was twice that of GFP-AR-R840C. In transcriptional assay, both
mutants were active only at high concentrations of androgen. The nuclear
trafficking of the mutants was evaluated by two parameters: 1) the rate of
nuclear transfer; and 2) the maximal amount of receptors imported into the
nucleus. At 10(-6) mol/L DHT, the GFP-AR mutants entered into the nucleus in a
fashion similar to that of GFP-AR-wt. At 10(-7) mol/L DHT, the rate and maximal
degree of nuclear import were both reduced, even more, for GFP-AR-G743V. The
difference between mutants was more pronounced at 10(-9) mol/L DHT, because GFP
AR-G743V entered into the nucleus with even slower kinetics. Though the androgen
binding affinity and transcriptional activity assays did not reveal major
differences between mutants, the dissociation rate and the trafficking capacity
measurements permitted the activity of the mutants to be differentiated. We
observed that the nuclear transfer capacities of these mutants are in correlation
with the severity of the phenotype. The GFP-AR model provides an opportunity both
to observe the dynamics of the hormone/receptor complex in living cells and to
study the impact of the ligand-binding domain mutation, as opposed to certain in
vitro techniques. Because the nuclear import capacity correlates well with the
degree of androgen insensitivity, the GFP-AR is a useful complementary tool to
understanding the phenotype/genotype relationship of AR function in patients with
AIS.
PMID- 9768672
TI - Complete thyroxine-binding globulin (TBG) deficiency produced by a mutation in
acceptor splice site causing frameshift and early termination of translation (TBG
Kankakee).
AB - Fourteen T4-binding globulin (TBG) variants have been identified at the gene
level. They are all located in the coding region of the gene and 6 produce
complete deficiency of TBG (TBG-CD). We now describe the first mutation in a
noncoding region producing TBG-CD. The proband was treated for over 20 yr with L
T4 because of fatigue associated with a low concentration of serum total T4.
Fifteen family members were studied showing low total T4 inherited as an X
chromosome-linked trait, and affected males had undetectable TBG in serum.
Sequencing of the entire coding region and promoter of the TBG gene revealed no
abnormality. However, an A to G transition was found in the acceptor splice
junction of intron II that produced a new HaeIII restriction site cosegregating
with the TBG-CD phenotype. Sequencing exon 1 to exon 3 of TBG complementary DNA
reverse transcribed from messenger RNA of skin fibroblasts from an affected male,
confirmed a shift in the ag acceptor splice site. This results in the insertion
of a G in exon 2 and causes a frameshift and a premature stop at codon 195. This
early termination of translation predicts a truncated TBG lacking 201 amino
acids.
PMID- 9768673
TI - Augmentation of leptin synthesis and secretion through activation of protein
kinases A and C in cultured human trophoblastic cells.
AB - Leptin is a fat cell-derived hormone that regulates food intake and energy
expenditure. We previously demonstrated that leptin is produced by nonadipose
cells, i.e. by placental trophoblasts. We also reported that a human
trophoblastic cell line, BeWo cells, expresses leptin gene and secretes leptin
into culture media. To elucidate the regulatory mechanisms of leptin production
by human trophoblasts, we investigated synthesis and secretion of leptin in BeWo
cells and in explant cultures of human placental tissue. Leptin production and
gene expression in BeWo cells were increased by treatment with forskolin. The
forskolin-induced increase in leptin production was completely suppressed by H89,
an inhibitor of protein kinase A. Leptin production and gene expression in BeWo
cells were increased by treatment with phorbol myristate acetate (PMA). The PMA
induced increase in leptin production was completely suppressed by H7 and
staurosporine, both of which are inhibitors of protein kinase C. Leptin secretion
from first trimester chorionic tissue was approximately 50-fold greater than that
from term placental tissue. Leptin production and gene expression in explant
cultures of placental tissue at both stages of pregnancy were augmented markedly
by treatment with forskolin or PMA. The present study demonstrated augmentation
of leptin production by protein kinase A and protein kinase C in cultured human
trophoblasts, thereby leading to a better understanding of the regulatory
mechanisms of leptin production in human trophoblasts in vivo.
PMID- 9768674
TI - Mutational analysis of PHEX gene in X-linked hypophosphatemia.
AB - Hypophosphatemic rickets is commonly an X-linked dominant disorder (XLH or HYP)
associated with a renal tubular defect in phosphate transport and bone
deformities. The XLH gene, referred to as PHEX, or formerly as PEX (phosphate
regulating gene with homologies to endopeptidases on the X-chromosome), encodes a
749-amino acid protein that putatively consists of an intracellular,
transmembrane, and extracellular domain. PHEX mutations have been observed in XLH
patients, and we have undertaken studies to characterize such mutations in 46
unrelated XLH kindreds and 22 unrelated patients with nonfamilial XLH by single
stranded conformational polymorphism and DNA sequence analysis. We identified 31
mutations (7 nonsense, 6 deletions, 2 deletional insertions, 1 duplication, 2
insertions, 4 splice site, 8 missense, and 1 within the 5' untranslated region),
of which 30 were scattered throughout the putative extracellular domain, together
with 6 polymorphisms that had heterozygosity frequencies ranging from less than
1% to 43%. Single stranded conformational polymorphism was found to detect more
than 60% of these mutations. Over 20% of the mutations were observed in
nonfamilial XLH patients, who represented de novo occurrences of PHEX mutations.
The unique point mutation (a-->g) of the 5'untranslated region together with the
other mutations indicates that the dominant XLH phenotype is unlikely to be
explained by haplo-insufficiency or a dominant negative effect.
PMID- 9768675
TI - Expression of the growth hormone secretagogue receptor in pituitary adenomas and
other neuroendocrine tumors.
AB - Synthetic GH secretagogues (GHSs; GH-releasing peptides and their nonpeptide
mimetics) stimulate GH release, activate the hypothalamo-pituitary-adrenal axis,
and release PRL in vivo. Patients with acromegaly show an exuberant GH response
to GHSs, whereas patients with pituitary-dependent ACTH-secreting tumors show an
exaggerated rise in ACTH and cortisol. We, therefore, studied the presence of GHS
receptor (GHS-R) messenger ribonucleic acid (RNA) in 38 human pituitary tumors of
different cell types, 3 ectopic ACTH-secreting tumors, a pancreatic gastrinoma, 3
insulinomas, and a non-secreting thymic carcinoid as well as in 7 normal
pituitary glands. Certain pituitary tumors were also studied by in vitro cell
culture with measurement of secreted GH, ACTH, PRL, FSH, LH, alpha-subunit, and
TSH. RNA was extracted from tissue samples and, after RT, a duplex PCR reaction
with primers for the GHS-R gene and for the housekeeping gene glyceraldehyde-3
phosphate dehydrogenase was performed, allowing semiquantitation of GHS-R
expression. All the somatotroph adenomas (n = 8) showed a 2-10 times higher
expression of the GHS-R gene compared to normal pituitaries. Higher than normal
expression was shown in 5 of 18 tumors from patients with ACTH-secreting
pituitary adenomas and in 1 of 3 ectopic ACTH-secreting carcinoid tumors. Two of
the pituitary ACTH-secreting adenoma samples showed completely absent expression
of the GHS-R, 8 showed expression similar to that of normal pituitary tissue, and
3 of the corticotroph adenoma tissue samples and 2 ectopic ACTH-secreting tumors
showed a very low level of expression. One of 4 prolactinoma samples showed a
high level of expression, 1 showed expression similar to that of normal
pituitary, and 2 samples showed a very low level of expression. Nonfunctioning
pituitary adenoma samples showed either absent or very low level expression of
the GHS-R. The pancreatic gastrinoma sample showed expression similar to that of
normal pituitary tissue, whereas 3 insulinomas showed low level expression of the
GHS-R gene; a nonsecreting thymic carcinoid tumor showed no detectable
expression. In summary, although GHS-R messenger RNA is abundant in human
somatotroph adenomas, it is also present in other pituitary adenomas,
particularly ACTH-secreting tumors. These findings may explain the in vivo
responses to GHSs in patients harboring such tumors. It also appears from our
study that GHS-R may be expressed in other neuroendocrine tumors.
PMID- 9768676
TI - RET/PTC and RET tyrosine kinase expression in adult papillary thyroid carcinomas.
AB - The prevalence of RET/PTC rearrangements in papillary thyroid carcinomas (PTCs)
varies widely in different studies, and an association of RET/PTC presence with
tumor behavior remains to be clarified. A prospective study of 50 adult PTCs
examined, using RT-PCR, the prevalence of the 3 main RET rearrangements and also
of RET tyrosine kinase (TK) domain sequence expression. The genetic findings were
correlated with the MACIS clinical prognostic score and with individual clinical
parameters. Three of the patients had been exposed to radiation in childhood or
adolescence. Four of the PTCs contained RET/PTC1, confirmed by sequencing, and
none contained RET/PTC2 or RET/PTC3. The prevalence of RET rearrangements overall
was 8%, but in the subgroup of 3 radiation-exposed patients it was 66.6%.
Interestingly, RET tyrosine kinase domain messenger ribonucleic acid was
detectable in 70% of PTCs using RET exon 12/13 primers and was detectable in 24%
of PTCs using RET exon 15/17 primers. RT-PCR for calcitonin and RET extracellular
domain, however, was negative. There was no association between the presence or
absence of RET/PTC in the patient's tumor and clinical parameters. We conclude
that RET/PTC1 is the predominant rearrangement in PTCs from adults with a history
of external irradiation in childhood. RET TK messenger ribonucleic acid
expression is common in PTCs, using RT-PCR, and cannot be used to infer the
presence of specific RET rearrangements or of RET activation.
PMID- 9768677
TI - Expression of 5alpha-reductase in the human temporal lobe of children and adults.
AB - Androgens exert important biological effects on the brain, and 5alpha-reductase
plays a crucial role in androgen metabolism. Therefore, we investigated the
expression of the two isozymes of 5alpha-reductase in the human temporal lobe to
determine the predominant isoform and to elucidate the existence of possible sex
differences and differences between children and adults. We studied biopsy
materials from the temporal lobe of 34 women, 32 men, and 12 children.
Quantification of 5alpha-reductase 1 and 2 messenger ribonucleic acid (mRNA) was
achieved by competitive RT-PCR. 5Alpha-reductase activity was determined in
tissue homogenates using [1,2-3H]androstenedione as the substrate. Only 5alpha
reductase 1 mRNA was expressed in human temporal lobe tissue; 5alpha-reductase 2
mRNA was not expressed. 5Alpha-reductase 1 mRNA concentrations did not differ
significantly in the cerebral cortex of women [25.9+/-7.9 arbitrary units (aU);
mean +/-SEM] and men (20.4+/-2.8 aU) or in the cerebral cortex (23.3+/-4.4 aU)
and the subcortical white matter of adults (32.6+/-5.6 aU), but they were
significantly higher in the cerebral cortex of adults than in that of children
(6.4+/-2.3 aU; P < 0.005). The apparent Km of 5alpha-reduction did not show
significant differences between the two sexes. In conclusion, 5alpha-reductase 1
mRNA is expressed in the temporal lobe of children and adults, but 5alpha
reductase 2 mRNA is not. 5Alpha-reductase 1 mRNA concentrations did not differ
significantly in the sexes, but they were significantly higher in specimens of
adults than in those of children.
PMID- 9768678
TI - Low growth hormone-binding protein in infants with congenital hypothyroidism.
AB - We evaluated the circulating levels of GH, insulin-like growth factor I (IGF-I),
GH-binding protein (GHBP), and IGF-binding protein-3 (IGFBP-3) before L-T4
therapy in 19 infants with congenital hypothyroidism (CH), aged 12-29 days,
diagnosed by neonatal screening and in a group of age- and sex-matched control
infants. The same parameters were reevaluated after several months of treatment.
Serum GHBP was measured by the high performance liquid chromatography-gel
filtration method; serum GH, IGF-I, and IGFBP-3 levels were determined by
commercial kits. The hypothyroid patients, before beginning therapy, presented
significantly lower GHBP values than controls (P < 0.0001); during treatment,
these values increased significantly; however, after 6 months they were still
significantly lower than control values (P < 0.01). The pretreatment levels of GH
were not significantly different from control values; after 1 month of treatment,
GH did not show the decrease observed in controls and, therefore, was
significantly higher (P < 0.01). The pretreatment levels of IGF-I were not
significantly different from control values, but were lower in patients with
severe than in those with mild hypothyroidism. They decreased at about 4 months
of life and became significantly lower than control values at about 7 months of
age (P < 0.05). In conclusion, it may be hypothesized that the condition of CH
induces a change in GHBP expression, perhaps beginning in fetal life. The
intrauterine production of IGF-I seems to be independent of the levels of GHBP
and partially affected by fetal thyroid function.
PMID- 9768679
TI - Chronic antagonism of nuclear factor-kappaB activity in cytotrophoblasts by
dexamethasone: a potential mechanism for antiinflammatory action of
glucocorticoids in human placenta.
AB - Circulating glucocorticoids are present in increasing quantities as human
gestation progresses, peaking during labor whether it occurs before or at term.
Although the precise role of glucocorticoids in pregnancy is not well defined, it
is clear that glucocorticoids suppress inflammation in many cell types by
antagonizing the acute stimulatory actions of members of the Rel/nuclear factor
kappaB (NF-kappaB) family on cytokine gene expression. In the present study we
tested the hypothesis that during pregnancy, glucocorticoids chronically suppress
inflammation in the human placenta. Cytotrophoblasts obtained from human term
placentas were maintained for 48 h in culture medium supplemented with 10%
charcoal-stripped calf serum with and without 100 nmol/L dexamethasone (DEX).
Enzyme-linked immunosorbent assay studies revealed that cytotrophoblasts
constitutively express interleukin-8 (IL-8), a known mediator of placental
inflammation, between 24-96 h of culture. A 48-h treatment of cytotrophoblasts
with 100 nmol/L DEX significantly reduced the production of IL-8 to 24+/-1% of
control levels (P < 0.01). DEX and cortisol mediated a dose-dependent inhibition
of IL-8 expression, with ED50 values of 5 and 50 nmol/L, respectively. DEX
treatment also significantly reduced levels of IL-6 and tumor necrosis factor
alpha in culture medium, suggesting that glucocorticoids coordinately reduce
cytokine levels in cytotrophoblasts. As cytokine expression is regulated by NF
kappaB and activator protein-1 (AP-1) transcription factors, electrophoretic
mobility shift assays (n = 4) were used to determine whether DEX treatment
altered the binding of nuclear proteins from cytotrophoblasts to labeled
oligonucleotides corresponding to the kappaB and AP-1 response elements. We
observed that a 48-h treatment of cytotrophoblasts with 100 nmol/L DEX markedly
reduced binding of nuclear extracts from cytotrophoblasts to the kappaB response
element. DEX treatment promoted a relatively smaller reduction of binding to the
AP-1 response element. Northern blotting experiments revealed that DEX treatment
did not alter the level of IkappaB, p50, or p65 messenger ribonucleic acid,
suggesting that the antiinflammatory action of glucocorticoid in cytotrophoblasts
did not directly involve alterations in the level of NF-kappaB proteins. Our
results demonstrate a novel chronic suppressive action of glucocorticoid on
cytokine production and nuclear binding of NF-kappaB and AP-1 proteins in
cytotrophoblasts, providing a potential mechanism through which glucocorticoids
may suppress inflammation at maternal-fetal interfaces across gestation.
PMID- 9768680
TI - Elevated nocturnal melatonin is a consequence of gonadotropin-releasing hormone
deficiency in women with hypothalamic amenorrhea.
AB - Elevated nocturnal melatonin is found in women with idiopathic hypogonadotropic
hypogonadism (IHH), but it is not known whether this is implicated in the
etiology of their GnRH deficiency. It is unlikely that nocturnal melatonin can be
implicated in the etiology of the GnRH deficiency of Kallmann's syndrome (KS),
because this condition is caused by defective neuronal migration in embryonic
life. We therefore measured nocturnal melatonin in women with IHH and KS to
determine whether it was elevated in one or both conditions and thereby to
determine whether it was implicated as cause or consequence of GnRH deficiency.
Four women with IHH, 3 women with KS, and 7 individually matched (age and body
size) controls were recruited. Frequent day- and nighttime samples were taken for
LH pulsatility studies. All patients showed absent or diminished LH pulsatility,
compared with their respective controls. Samples were also taken over 24 h for
melatonin and 6-sulphatoxymelatonin (the principle metabolite of melatonin and an
independent marker of its secretion). Melatonin and 6-sulphatoxymelatonin levels
were elevated in 6 of 7 patients (compared with their matched controls) and were
significantly elevated in the KS group (compared with their controls). The
finding of elevated nocturnal melatonin (and its metabolite) in GnRH-deficient
women with KS (as well as IHH) suggests that nocturnal melatonin is elevated as a
consequence of GnRH deficiency, irrespective of its etiology.
PMID- 9768681
TI - Growth hormone (GH) response to GH-releasing peptide-6 in type 1 diabetic
patients with exaggerated GH-releasing hormone-stimulated GH secretion.
AB - In type 1 diabetes mellitus (DM 1), high GH basal levels and exaggerated GH
responses to several stimuli, including GHRH, have been described. GH-releasing
peptide-6 (GHRP-6) is a synthetic hexapeptide that specifically stimulates GH
release, both in vitro and in vivo. The aim of this study was to evaluate the
effects of GHRP-6 alone or in combination with GHRH on GH secretion in DM 1. Six
type 1 diabetic males and six age-, sex-, and body mass index-matched control
volunteers were studied. Each subject received GHRH (100 microg iv), GHRP-6 (90
microg iv), and GHRH plus GHRP-6 on three separate days. GH peak values were
higher in DM 1 patients than in control volunteers, after GHRH (52.2+/-9.8 vs.
19.3+/-6.0 microg/L; P = 0.016), GHRP-6 (66.2+/-9.6 vs. 39.9+/-6.3 microg/L; P =
0.05), and GHRH plus GHRP-6 (81.8+/-4.4 vs. 53.7+/-8.2 microg/L; P = 0.01). An
additive GH response to combined administration of these two peptides was
observed in diabetic patients. Serum insulin-like growth factor (IGF)-1 levels
were diminished in DM 1, with respect to normal subjects (145.2+/-21.5 vs.
269.7+/-42.0 microg/L; P = 0.01), whereas IGF-binding protein-3 levels were not
significantly different between DM-1 and controls. In summary, GHRP-6 is a potent
stimulus for GH secretion in DM 1. The combined administration of GHRP-6 plus
GHRH constitutes the most powerful stimulus for GH secretion in DM 1. These
patients exhibit a greater GH secretory capacity than normal subjects, probably
caused by a diminished tone in the IGF-1 sustained negative feedback control
exerted upon somatotroph responsiveness.
PMID- 9768682
TI - Therapeutic usefulness of wild-type p53 gene introduction in a p53-null
anaplastic thyroid carcinoma cell line.
AB - Anaplastic thyroid carcinomas very often harbor the mutations in the tumor
suppressor gene p53. We have previously shown that wild-type (wt) p53 gene
introduction led to cell growth arrest, but not apoptosis, in p53-null anaplastic
thyroid carcinoma cells. The present studies were designed to evaluate other
therapeutic effects of wt-p53 gene introduction on p53-null thyroid carcinoma
cells, as chemo- and radiosensitization and inhibition of angiogenesis have also
been described recently as additional therapeutic advantages of wt-p53 gene
introduction in tumor cells with p53 mutations. A p53-null anaplastic thyroid
carcinoma cell line, FRO, and a FRO subline stably expressing a temperature
sensitive (ts) mutant of p53 (p53Val138), tsFRO, were used. ts-p53 functions as
mutant and wt at nonpermissive (37 C) and permissive (32 C) temperatures,
respectively. tsFRO showed a prolonged cell doubling time compared to parental
FRO when cultured at 32 C, but the cell growth rate was similar between FRO and
tsFRO at 37 C. The cytotoxic and clonogenic assays demonstrated that although the
sensitivity to three different anticancer agents (cisplatin, 5-fluorocytosine,
and doxorubicin) was unaltered, radiosensitivity was enhanced in tsFRO compared
to FRO at 32 C. Unexpectedly, in studies on angiogenesis, expression levels of
vascular endothelial growth factor (an angiogenic factor) messenger ribonucleic
acid were similar between FRO and tsFRO, and thrombospondin-1 (an antiangiogenic
factor) messenger ribonucleic acid and protein levels were about 2.5-fold lower
in tsFRO than FRO at 32 C, although any difference could not be detected in their
ability to inhibit in vitro angiogenesis with the culture medium conditioned by
tsFRO and FRO at 32 C. These results suggest that p53-defective thyroid
carcinomas may benefit from the combination of p53 gene therapy and radiotherapy.
However, further study will be necessary to clarify the pathological significance
of thrombospondin-1 in angiogenesis and thyroid tumor growth.
PMID- 9768683
TI - Fibronectin is required to prevent thyroid cell apoptosis through an integrin
mediated adhesion mechanism.
AB - Apoptosis or programmed cell death occurs in a wide variety of cell types when
adhesion to extracellular matrix (ECM) is denied. Invasion and metastasis by
tumor cells involve the loss of normal cell-ECM contacts and require independence
from such control mechanisms. We studied whether the immortalized thyroid cell
line TAD-2 is a model suitable to investigate thyroid cell-ECM interaction, and
we analyzed the role of integrin-fibronectin (FN) interaction in apoptosis.
Adhesion, spreading, and cytoskeleton organization in TAD-2 cultured cells were
dependent upon integrin-FN interaction. Cell spreading and cytoskeletal
organization were coupled to deposition of insoluble FN induced by serum.
Expression of integrin-FN receptors was demonstrated by flow cytofluorometry with
specific antibodies, and strong integrin-dependent adhesion was demonstrated by
attachment assays to immobilized FN. Apoptosis, occurring in different culture
conditions, was determined by cell morphology and DNA electrophoretic analysis
and quantitated by flow cytometry in propidium iodide-stained cells. Thyroid
cells underwent apoptosis in the presence of serum when adhesion was prevented by
specific peptides that inhibit integrin binding to FN (RGD-containing peptides)
or by coating the culture plates with agar. In serum-free cultures, apoptosis was
prevented by insoluble FN immobilized on the plates, but not by soluble FN. These
results suggest that the TAD-2 cell line is a good model to study thyroid cell
ECM interaction, that FN, assembled into insoluble matrix, is required for
cytoskeletal organization and to prevent thyroid cell apoptosis, and that
integrin-mediated adhesion is involved in this process.
PMID- 9768684
TI - Change of peripheral levels of pituitary hormones and cytokines after injection
of interferon (IFN)-beta in patients with chronic hepatitis C.
AB - Interferons (IFNs) are now in use worldwide for the treatment of chronic viral
hepatitis. Unfortunately, various side effects of IFNs have been reported.
Because cytokines, which include IFNs, can affect endocrine function,
endocrinological abnormalities are sometimes observed in patients treated with
IFNs. We examined the effects of IFN-beta on peripheral levels of pituitary and
adrenal hormones and cytokines. Six million international units of IFN-beta
dissolved in glucose solution was injected for 30 min. As a control study,
glucose solution without IFN-beta was injected. Pituitary hormones (ACTH, GH,
TSH, prolactin (PRL), LH, FSH, and arginine-vasopressin (AVP)), cortisol, and
cytokines such as interleukin (IL)-1, IL-6, tumor necrosis factor-alpha (TNF),
and interleukin-1 receptor antagonist (IL-1ra) were measured before and after IFN
beta injection. The study was carried out on 14 patients with chronic hepatitis
type C who were under treatment with IFN-beta. All studies were performed when
the patients were afebrile. None of the patients had any endocrine or autoimmune
diseases. Plasma ACTH levels increased significantly at 60-120 min after IFN-beta
injection compared with the levels before IFN-beta injection and in the control
study using glucose injection. Plasma cortisol levels increased after IFN-beta
injection, in parallel with plasma ACTH elevation. Serum GH levels increased
significantly at 120 min after IFN-beta injection. All the increased hormones
including ACTH, cortisol, and GH, were decreased at the end of the study-180 min
after IFN-beta injection. Serum levels of TSH, PRL, LH, FSH, and AVP were not
changed significantly by IFN-beta injection. Plasma IL-1 and TNF levels did not
change after IFN-beta injection, while IL-6 and IL-1ra were elevated
significantly. The increases in IL-6 and IL-1ra were gradual, reaching their peak
levels at 180 min after IFN-beta injection. However there were no correlations
between the hormones measured in this study and the levels of IL-6 or IL-1ra. It
would seem that IFN-beta has direct or indirect stimulatory effects for ACTH and
GH without mediation of the cytokines. These in vivo results are important for
investigating the relationship between endocrine and cytokine systems in humans.
PMID- 9768685
TI - Mutations in the genomic deoxyribonucleic acid for SLC3A1 in patients with
cystinuria.
AB - Cystinuria is an inherited transport disorder characterized by defective renal
resorption of cystine and other dibasic amino acids. We have studied the
occurrence of mutations in the SLC3A1 gene, which codes for a dibasic amino acid
transporter-like protein, in 33 unrelated cystinurics. We found mutations in 34
of the 66 chromosomes studied. There were 14 different mutations in our study
population, 8 of which had not been previously described. Of these new mutations,
4 were missense mutations: G1934C, C1259G, T1607G, and G1373A. The other 4
mutations consisted of a single base insertion mutation (2022 ins T), a single
base deletion mutation (163 del C), a 23-base deletion mutation (del 782A-804A),
and a complex mutation that consisted of a 36-base deletion (del C431-3 to T463)
and a duplication insertion of 468 T to 474 A after nucleotide 474.
PMID- 9768686
TI - Adrenarche results from development of a 3beta-hydroxysteroid dehydrogenase
deficient adrenal reticularis.
AB - Adrenarche is the increased adrenal production of dehydroepiandrosterone (DHEA)
and dehydroepiandrosterone sulfate (DHEAS) that occurs during the prepubertal
period. To date, the exact mechanism initiating adrenarche is unknown, although
many factors have been postulated. In the present study, we examined the
hypothesis that alterations in intra-adrenal expression of 3beta-hydroxysteroid
dehydrogenase (3betaHSD) or 21-hydroxylase (CYP21) within the inner reticularis
zone leads to the increased production of 19-carbon (C19) steroids. After
conversion of cholesterol to pregnenolone, 17alpha-hydroxylase/17,20-lyase
(CYP17) can metabolize pregnenolone through to DHEA. The enzyme 3betaHSD competes
for substrate with CYP17 and effectively removes steroid precursor from the
pathway leading to DHEA. On the other hand, deficiency in CYP21 expression is
known to cause excessive production of adrenal C19 steroids, suggesting that
CYP21 could play a role in adrenarche. Thus, a decrease in 3betaHSD or CYP21
expression would allow substrate to flow toward the synthesis of DHEA. To
determine whether adrenarche results from a decreased expression of 3betaHSD or
CYP21 in the reticularis, immunohistochemical localization of 3betaHSD and CYP21
was performed, and staining intensities compared using adrenal glands from
children ages 4 months to 4 yr (n = 12), ages 5-7 yr (n = 9), ages 8-13 yr (n =
9), and adults ages 25-56 yr (n = 8). There were no differences in the zonal
expression of CYP21. No difference in 3betaHSD staining was observed between the
glomerulosa and fasciculata from any age group. However, children age 8 yr and
older show a significant decrease in 3betaHSD expression in reticularis as
compared with the fasciculata. No significant difference was noted for 3betaHSD
levels between the fasciculata and reticularis for children age 7 yr or younger.
The level of 3betaHSD expression in the reticularis continued to decrease in the
adult adrenals examined. These findings suggest that as children mature there is
a decreased level of 3betaHSD in the adrenal reticularis that may contribute to
the increased production of DHEA and DHEAS seen during adrenarche.
PMID- 9768687
TI - Potential for estrogen synthesis and action in human normal and neoplastic
thyroid tissues.
AB - To investigate the potential of intracrine or paracrine estrogen synthesis and
action in the human thyroid gland and thyroid tumors, the presence of the
messenger ribonucleic acids (mRNAs) of both cytochrome P450 aromatase (P450arom)
and estrogen receptor (ER) was investigated by RT-PCR with primers designed on
the respective coding regions and Southern hybridization analysis with specific
probes in neoplastic (n = 42), hyperplastic (n = 7), and adjacent histologically
normal thyroid tissues (n = 33) obtained from 43 female and 7 male patients. Most
thyroid tissues were positive for both mRNAs, but 2 normal and 3 neoplastic
tissues were negative for P450arom mRNA only, 3 normal and 1 hyperplastic tissues
were negative for ER mRNA only, and 2 normal tissues were double negative. In
some patients, P450arom mRNA was absent in either the neoplastic tissue or the
normal one. Single and double negative samples were relatively more frequent in
men (n = 4) than in women (n = 7). All negative samples were positive for beta
actin mRNA. RT-PCR amplification and Southern blotting of promoter-specific
untranslated 5'-termini revealed that the human thyroid gland and tumors mainly
use the ovarian-type promoter, promoter II, for CYP19 expression. Transcripts
with either exon I.4 or I.1 were present only in some samples and in very low
copy number. When 18 neoplastic samples with their surrounding normal tissues
were analyzed immunohistochemically, 57% of those that were positive for P450arom
mRNA also had a positive immunoresponse for the corresponding protein. In the
case of ER, the percentage was 58%. Immunostaining for P450arom was often
particularly intense in neoplastic samples. When 3 adenomata and 1 papillary
cancer were incubated with [1,2,6,7-3H]testosterone, 17beta-estradiol could be
radiochemically identified with a maximal yield of 10.5 fmol/mg x h. In
conclusion, the human thyroid gland appears to have the potential for both
estrogen synthesis and intracrine or paracrine estrogen responsiveness, which
seem to be greater in women than men and may become enhanced with the process of
tumorigenesis.
PMID- 9768688
TI - 17Beta-hydroxysteroid dehydrogenase types 1 and 2 in human placenta: an
immunohistochemical study with correlation to placental development.
AB - In estrogen metabolism, the enzymatic properties of the 17beta-hydroxysteroid
dehydrogenase (17betaHSD) isozymes play very important roles in steroid hormone
metabolism in various tissues, including the placenta. 17betaHSD type 1 catalyzes
primarily the reduction of estrone (E1) to estradiol (E2), whereas 17betaHSD type
2 catalyzes primarily the oxidation of E2 to E1. In this study, we examined
immunohistochemical localization of 17betaHSD types 1 and 2 in human placenta (31
cases) ranging from 4-40 weeks gestation. The immunoreactivity of 17betaHSD type
1 was exclusively detected in syncytiotrophoblast from 4 weeks gestation to term
placenta. Immunoreactivity of 17betaHSD type 2 first appeared in endothelial
cells of intravillous vessels at 12 weeks gestation, and the number of 17betaHSD
type 2-positive endothelial cells markedly increased up to 19 weeks, then reached
a plateau. We quantitatively evaluated the 17betaHSD type 2-positive endothelial
cells in chorionic villi and determined the ratio of 17betaHSD type 2-positive
endothelial cells using immunohistochemistry of CD34, an endothelial antigen, in
serial mirror tissue sections and subsequent image analysis using CAS 200. CD34
was detected from 4 weeks gestation, and its positive areas continued to increase
toward term. The 17betaHSD type 2-positive area per CD34-positive area markedly
increased from 13 weeks gestation and reached a plateau at 19 weeks gestation, in
which almost all endothelial cells were positive for 17betaHSD type 2. 17BetaHSD
type 2, therefore, is considered to prevent the passage of excessive estrogens
into the fetal circulation at endothelial cells of the intravillous fetal
capillaries by catalyzing the inactivation ofE2 to E1.
PMID- 9768689
TI - Corticotropin-releasing hormone and proopiomelanocortin-derived peptides are
present in human myometrium.
AB - CRH and POMC-derived peptides are produced at a number of intrauterine sites in
both the nonpregnant and pregnant states. It is hypothesized that CRH and POMC
derived peptides may be produced locally by the uterus to modulate myometrial
contractility. This study has examined the distribution of these peptides in
human uterine tissue during the ovulatory cycle and pregnancy. The
immunoperoxidase staining method was used to localize CRH and POMC-derived
peptides: ACTH, beta-endorphin, and alphaMSH. Immunoreactive (IR-) CRH and IR
POMC-derived peptides, beta-endorphin and alphaMSH, were observed in the
myometrial smooth muscle, vascular smooth muscle, endometrial glandular
epithelium, and luminal epithelium of the nonpregnant uterus (n = 17). Staining
for IR-CRH did not change during the cycle from the proliferative (n = 8) to the
secretory phases (n = 9). Conversely, staining for IR-beta-endorphin and IR
alphaMSH was only observed during the secretory phase of the cycle (n = 9). In
uterine tissue obtained from pregnant women (n = 20) IR-CRH was present in the
myometrial smooth muscle, vascular smooth muscle, decidua, and glandular
epithelium. IR-POMC-derived peptides were not detectable at any uterine site
during pregnancy (n = 20). IR-CRH was measurable in myometrial extracts collected
from pregnant women undergoing cesarean section (20.9+/-3.8 ng/g wet wt; n = 7)
and from nonpregnant premenopausal women undergoing hysterectomy (7.7+/-2.1 ng/g
wet wt; n = 6). IR-CRH concentrations significantly increased with pregnancy.
Levels of messenger ribonucleic acid encoding for CRH were examined in
nonpregnant (n = 4) and pregnant (n = 10) myometrial smooth muscle and were also
significantly increased with pregnancy. This study has demonstrated that levels
of CRH and POMC peptide in human uterine tissue change with pregnancy and that
CRH is produced locally by myometrial smooth muscle cells. These studies are
consistent with the possibility that the CRH peptide has an autocrine/paracrine
activity during pregnancy and labor that may be related to the modulation of
myometrial contractility.
PMID- 9768690
TI - Cyclic adenosine 3',5'-monophosphate-responsive element modulator gene expression
in germ cells of normo- and oligoazoospermic men.
AB - In about one third of infertile men the cause of impaired spermatogenesis is not
known. Spermatogenesis appears to be mediated at least in part by the pituitary
gonadotropins, which activate the cAMP-dependent signaling pathway. The end point
of this pathway is the activation of nuclear transcription factors, such as cAMP
responsive element-binding protein and cAMP-responsive element modulator (CREM).
These factors, upon binding to gene sequences identified as cAMP response
elements, modulate the expression of germ cell-specific genes that, in turn,
promote the completion of spermatogenesis. The expressions of the cAMP-responsive
element-binding protein and CREM genes create different isoforms, which can be
divided into two groups: activators or repressors of gene regulation. Only CREM
repressors are expressed in premeiotic germ cells in mice, whereas a switch to
the expression of the CREM activator tau is observed from postmeiotic germ cells
onward. Completion of germ cell maturation appears to be dependent on this
phenomenon. Recently, mice lacking CREM gene expression have been generated.
These animals were infertile and presented a developmental arrest of germ cell
maturation at the stage of early spermatid. In this report we demonstrate that
CREM gene expression also occurs in human germ cells. In particular, we
determined by RT-PCR that a switch from the expression of CREM repressors to CREM
activators is present in postmeiotic germ cells in normospermic men. Conversely,
in oligoazoospermic patients only the expression of CREM repressors was detected.
These data were confirmed by in situ hybridization studies in which transcripts
for CREM activators were detected in postmeiotic germ cells in testis specimens
showing conserved spermatogenesis, but not in specimens showing maturation arrest
at the spermatid stage. Thus, our results indicate that the lack of a switch in
the expression of CREM gene isoforms may be related to impaired spermatogenesis
in humans.
PMID- 9768691
TI - Phenotypic variability in familial combined pituitary hormone deficiency caused
by a PROP1 gene mutation resulting in the substitution of Arg-->Cys at codon 120
(R120C).
AB - As pituitary function depends on the integrity of the hypothalamic-pituitary
axis, any defect in the development and organogenesis of this gland may account
for a form of combined pituitary hormone deficiency (CPHD). A mutation in a
novel, tissue-specific, paired-like homeodomain transcription factor, termed
Prophet of Pit-1 (PROP1), has been identified as causing the Ames dwarf (df)
mouse phenotype, and thereafter, different PROP1 gene alterations have been found
in humans with CPHD. We report on the follow-up of two consanguineous families (n
= 12), with five subjects affected with CPHD (three males and two females) caused
by the same nucleotide C to T transition, resulting in the substitution of Arg-
>Cys in PROP1 at codon 120. Importantly, there is a variability of phenotype,
even among patients with the same mutation. The age at diagnosis was dependent on
the severity of symptoms, ranging from 9 months to 8 yr. Although in one patient
TSH deficiency was the first symptom of the disorder, all patients became
symptomatic by exhibiting severe growth retardation and failure to thrive, which
was mainly caused by GH deficiency (n = 4). The secretion of the pituitary
derived hormones (GH, PRL, TSH, LH, and FSH) declined gradually with age,
following a different pattern in each individual; therefore, the deficiencies
developed over a variable period of time. All of the subjects entered puberty
spontaneously, and the two females also experienced menarche and periods before a
replacement therapy was necessary.
PMID- 9768692
TI - Unchanged testosterone production rates in growth hormone-treated healthy men.
AB - The effect of biosynthetic human GH on the production rates of testosterone was
determined in healthy men (n = 7) using the stable isotope dilution technique and
mass spectrometry. 1Alpha,2alpha-d-testosterone (20 microg/h) was infused for 10
h (0800-1800 h). Blood samples obtained at 20-min intervals from 1400-1800 h were
pooled during two 2-h periods. Subsequently, each volunteer received a daily dose
of biosynthetic human GH (4 IU/day sc) for 7 days. This resulted in a rise in
plasma concentrations of somatomedin-C from, basal, 0.67+/-0.13 U/mL to 1.20+/
0.2 U/mL on day 7 (P < 0.0001). Testosterone production rates (basal: 209.9+/
31.0 microg/h) were unchanged by treatment with GH (day 7: 192.2+/-30.1
microg/h). In healthy men, short-term treatment with sc GH does not influence
endogenous testosterone production rates.
PMID- 9768693
TI - Systematic mutation screening of the pro-opiomelanocortin gene: identification of
several genetic variants including three different insertions, one nonsense and
two missense point mutations in probands of different weight extremes.
AB - Pro-opiomelanocortin (POMC) is the precursor of melanocortins
(adrenocorticotropin: ACTH, beta-endorphin, beta-lipotropin: beta-LPH,
corticotropin like intermediate peptide, alpha-, beta- and gamma-melanocyte
stimulating hormone: alpha-, beta- and gamma-MSH) some of which act in the brain
to reduce food intake and are potential mediators of leptin action. Recently,
three different mutations in the POMC gene (POMC) were identified in two
unrelated children that lead to early-onset extreme obesity, adrenal
insufficiency, and red hair pigmentation. In the present study we systematically
screened the coding region of POMC in 96 extremely obese children and
adolescents, 60 healthy underweight individuals and 46 patients with anorexia
nervosa (AN) and identified several variants. a) A 9 and an 18 base pair
insertion (9bp and 18bp: AGC AGC GGC and AGC AGC GGC AGC AGC GGC, respectively,
between codon 73 and 74; 1,2). These in-frame variants lead to the insertion of
three or six amino acids (Ser-Ser-Gly; Ser-Ser-Gly-Ser-Ser-Gly) carboxy-terminal
to gamma-MSH. Frequencies of the 9bp insertion allele varied between 3 and 5%
among the different study groups (Pearson's chi2 P>0.5). b) Both an out-of-frame
6 bp insertion (within codon 176: GGG CCC) leading to the insertion of two amino
acids (Arg-Ala) and a premature stop-codon (G-7316-T: Glu-180-Stop) within the
gamma-LPH sequence were maternally inherited in an obese female proband. This
proband inherited another missense mutation from her father (Glu-188-Gly). c) A
missense mutation (G-7016-A; Asp-80-Asn) was observed in a single patient with AN
who also harboured the 9bp insertion on a paternally derived haplotype. d) The
allelic co-occurence of two silent mutations (C-6982-T and C-7285-T) was detected
in two obese subjects. e) Two further silent mutations (C-3832-T; C-7111-G) were
detected in an underweight and an obese subject, respectively. We conclude that
the POMC gene harbors several different polymorphisms and mutations, none of
which can readily be associated with the phenotypes under study.
PMID- 9768694
TI - Synergistic effects of feeding and dexamethasone on serum leptin levels.
AB - The objectives of this study were to determine the time course of the stimulatory
effect of dexamethasone on serum leptin and whether it depends on food intake.
Dexamethasone (4mg) was administered I.V. over 1 minute to healthy human
volunteers (n=8) under fasting and feeding conditions (2000 kcal given at three
meals over 7 hours). At 10 hours, serum leptin levels were increased only in the
fed subjects (delta leptin 10.6+/-1.6 vs -2.4+/-1.9 ng/ml, p=0.01, n=8). To
assess the interactive effect of food and dexamethasone on serum leptin, a
subgroup (n=4) was studied under 4 conditions: 1) dexamethasone/fast; 2)
dexamethasone/food; 3) saline/fast; 4) saline/food. Serum leptin declined from
baseline under the fasting conditions, with or without dexamethasone. Feeding
prevented the drop in serum leptin. In the dexamethasone/food condition, leptin
levels rose from baseline after 7 hours and doubled after 10 hours (p<0.05). The
rise in serum leptin was significantly greater in the food/dexamethasone
condition compared to all other conditions (p<0.05). In summary, dexamethasone
has no independent effect on serum leptin in the absence of food intake. Rather,
dexamethasone appears to potentiate the food-induced increase in serum leptin.
This synergism may be mediated by insulin and/or other factors associated with
food ingestion.
PMID- 9768695
TI - Immunohistochemical localization of somatostatin receptor sst2A in human
pancreatic islets.
AB - Somatostatin and octreotide inhibit endocrine pancreatic functions in man, via
specific somatostatin receptors. However, the cellular distribution of the
different somatostatin receptor subtype proteins has not been determined in the
human pancreas. Here, the immunohistochemical distribution of the sst2A receptor
was investigated using the sst2A receptor specific anti-peptide antibody R2-88 in
cryostat as well as in formalin-fixed paraffin-embedded sections of human
pancreatic tissue, and compared with insulin, glucagon and somatostatin
immunostaining of adjacent sections. All pancreatic islets were immunostained
with R2-88. Most islet cells were labeled: the sst2A receptors were present in
insulin as well as glucagon producing cells, but were not detected in intra-islet
vessels nor in adjacent acinar tissue. Absorption of the sst2A antibody with 100
nM of the antigen peptide abolished specific staining in tissue sections.
Immunohistochemical staining with R2-88 correlated with the labeling observed
after receptor autoradiography using the sst2-preferring radioligand, 125I-Tyr3
octreotide. Therefore, the clinical efficacy of octreotide on glucagon and
insulin release can be explained by the presence of sst2A receptors in human A
and B pancreatic islet cells. Moreover, absence of sst2A receptors in human
acinar tissue suggests that the action of somatostatin on pancreatic exocrine
secretion is mediated either indirectly or through a different somatostatin
receptor subtype on acinar cells.
PMID- 9768696
TI - Cortisol, androstenedione (A4), dehydroepiandrosterone sulphate (DHEAS) and 17
hydroxyprogesterone (17OHP) responses to low doses of (1-24)ACTH.
AB - The dose of 250 microg used in the standard short synacthen test is
supraphysiological and lower doses may provide a more sensitive test. We examined
steroid responses to 125ng/m2, 250ng/m2 and 500 ng/m2 (1-24)ACTH in 6 normal
males, looking at effects of dose and the within- and between-subject
coefficients of variation (CV). Subjects were given each dose 3 times, blood
samples were taken at 10 minute intervals. There was a dose response relationship
between dose of (1-24)ACTH and peak values for cortisol and 17OHP (p<0.05). There
was no difference between peaks of A4 at different doses and no clear peaks were
reached for DHEAS. 86% of the peaks for 17OHP, 63% for A4 and 25% for cortisol
were at 10 minutes and 14%, 29% and 65% respectively at 20 mins (p=0.001). Within
subject CV for cortisol was 12.6% and between subject 10.1%. Tests of adrenal
function using low doses of (1-24)ACTH have acceptable between- and within
subject CV for peak values with a dose as low as 125 ng/m2 (1-24)ACTH. Protocols
for low dose synacthen tests, with traditional sampling at zero, 30 and 60
minutes or even as shown here at 10 minute intervals, fail to fully define the
changes in steroid levels following adrenal stimulation. More frequent blood
sampling will be needed to accurately detect peak levels in particular of 17OHP
and A4.
PMID- 9768697
TI - Estrogen receptor beta: mine is longer than yours?
PMID- 9768698
TI - Coming of age in endocrinology.
PMID- 9768699
TI - A never-ending story of an insufficient iodine status without mandatory
iodization of foods?--A German experience.
PMID- 9768700
TI - Increased plasma 17-hydroxyprogesterone response to ACTH in patients with
nonhyperfunctioning adrenal adenomas is not due to a deficiency in 21-hydroxylase
activity.
PMID- 9768701
TI - Ovulation and spinal bone mineral density.
PMID- 9768702
TI - Comment on marked improvement in bone mass after parathyroidectomy in osteitis
fibrosa cystica.
PMID- 9768703
TI - Comment on apoptosis and Fas expression in human fetal membranes.
PMID- 9768704
TI - New Doppler echocardiographic applications for the study of diastolic function.
AB - Doppler echocardiography is one of the most useful clinical tools for the
assessment of left ventricular (LV) diastolic function. Doppler indices of LV
filling and pulmonary venous (PV) flow are used not only for diagnostic purposes
but also for establishing prognosis and evaluating the effect of therapeutic
interventions. The utility of these indices is limited, however, by the
confounding effects of different physiologic variables such as LV relaxation,
compliance and filling pressure. Since alterations in these variables result in
changes in Doppler indices of opposite direction, it is often difficult to
determine the status of a given variable when a specific Doppler filling pattern
is observed. Recently, color M-mode and tissue Doppler have provided useful
insights in the study of diastolic function. These new Doppler applications have
been shown to provide an accurate estimate of LV relaxation and appear to be
relatively insensitive to the effects of preload compensation. This review will
focus on the complementary role of color M-mode and tissue Doppler
echocardiography and traditional Doppler indices of LV filling and PV flow in the
assessment of diastolic function.
PMID- 9768705
TI - Effects of thrombolytic therapy in acute inferior myocardial infarction with or
without right ventricular involvement. HIT-4 Trial Group. Hirudin for Improvement
of Thrombolysis.
AB - OBJECTIVES: This study assessed the prognostic impact of right ventricular
involvement (RVI) in streptokinase-treated patients with inferior acute
myocardial infarction (AMI) stratified for small or large AMI. BACKGROUND: Only
scant data exist from small studies about the impact of reperfusion therapy on
survival in patients with RVI during inferior AMI. METHODS: Right ventricular
involvement was assessed by ST-segment elevation > or =0.1 mV in lead V4R and
infarct size by the extent of ST-segment deviation on the baseline
electrocardiogram: small AMI=sum ST-segment elevation < or =0.8 mV and no
precordial ST-segment depression (small ST); large AMI=presence of precordial ST
segment depression or sum ST-segment elevation >0.8 mV (large ST) in 522 inferior
AMI patients of the Hirudin for Improvement of Thrombolysis (HIT-4) Trial. In 187
patients, 90-min coronary angiography was performed. RESULTS: Right ventricular
involvement was present in 169 patients (32%). Higher 30-day cardiac mortality
rates with RVI (5.9% vs. 2.5%) were related to larger infarct size rather than to
RVI. For large ST, a proximal right coronary artery lesion was observed in 52%
with and in 23% without RVI. Patency rates at 90 min were similar (54% vs. 52%).
In the 28% of patients who had small ST, cardiac mortality was less than 1%
irrespective of the presence of RVI. Coronary artery lesions were mostly located
distally. Patency rates were 27% with and 80% without RVI. CONCLUSIONS: ST
segment elevation of > or =0.1 mV in V4R in inferior AMI patients is associated
with larger infarct size and higher 30-day mortality rates. Right ventricular
involvement is not an independent predictor of survival. In patients with small
ST, cardiac mortality is low, even if ST V4R is > or =0.1 mV.
PMID- 9768706
TI - Treatment of right ventricular infarction: thrombolytic therapy, coronary
angioplasty or neither?
PMID- 9768707
TI - Patients treated by cardiologists have a lower in-hospital mortality for acute
myocardial infarction.
AB - OBJECTIVES: We sought to determine the effect of specialty care on in-hospital
mortality in patients with acute myocardial infarction. BACKGROUND: There has
been increasing pressure to limit access to specialists as a method to reduce the
cost of health care. There is little known about the effect on outcome of this
shift in the care of acutely ill patients. METHODS: We analyzed the data from
30,715 direct hospital admissions for the treatment of acute myocardial
infarction in Pennsylvania in 1993. A risk-adjusted in-hospital mortality model
was developed in which 12 of 20 clinical variables were significant independent
predictors of in-hospital mortality. To determine whether there were factors
other than patient risk that significantly influenced in-hospital mortality,
multiple logistic regression analysis was performed on physician, hospital and
payer variables. RESULTS: After adjustment for patient characteristics, a
multiple logistic regression analysis identified treatment by a cardiologist
(odds ratio=0.83 [confidence interval ?CI?=0.74 to 0.94] p < 0.003) and
physicians treating a high volume of acute myocardial infarction patients (odds
ratio=0.89 [CI=0.80 to 0.99] p < 0.03) as independent predictors of lower in
hospital mortality. Treatment by a cardiologist as compared to primary care
physicians was also associated with a significantly lower length of stay for both
medically treated patients (p < 0.01) and those undergoing revascularization (p <
0.01). CONCLUSIONS: Treatment by a cardiologist is associated with approximately
a 17% reduction in hospital mortality in acute myocardial infarction patients. In
addition, patients of physicians treating a high volume of patients have
approximately an 11% reduction in mortality. This has important implications for
the optimal treatment of acute myocardial infarction in the current
transformation of the health care delivery system.
PMID- 9768708
TI - Prediction of short- and intermediate-term prognoses of patients with acute
myocardial infarction using myocardial contrast echocardiography one day after
recanalization.
AB - OBJECTIVES: This study sought to determine whether microvascular integrity in the
risk area (RA) for myocardial infarction (MI) one day after recanalization
predicts the outcome in patients with first acute MI. BACKGROUND: Immediately
after recanalization, microcirculation in the RA is modified by both hyperemic
response and microvascular impairment. METHODS: Fifty consecutive patients who
underwent serial myocardial contrast echocardiography before and one day after
recanalization (day 2) were studied. All patients had a completely occluded
lesion in the left anterior descending coronary artery alone, and underwent
successful reperfusion therapy. The relative size of the initial RA (RA ratio)
and peak gray scale ratio (PGSR) within the RA on day 2 were determined. Patients
were followed for a median of 22 months to evaluate clinical outcome. RESULTS: On
day 2, PGSR was a median of 0.46. Study patients were subdivided into two groups,
group A of 24 patients with acceptable opacification (PGSR > 0.46 on day 2) and
group B of 26 patients without it. Major cardiac events (cardiac death, nonfatal
MI and repeat admission for congestive heart failure) were more frequently
observed in group B (28% vs. 4%, Cox hazard ratio=8.5, p=0.05, 95% confidence
interval [CI] 1.03 to 69.9). The median value of the RA ratio was 0.45. Patients
(n=15) with RA ratio > 0.45 on day 1 and PGSR on day 2 < or = 0.46 exhibited a
10.7-fold relative risk for major cardiac events (p=0.005, 95% CI 2.06 to 55.8)
and a 3.69-fold relative risk for composite cardiac events (major cardiac events
and target lesion revascularizations) after the initial intervention (p=0.004,
95% CI 1.51 to 9.04). CONCLUSIONS: The assessment of both the size of the initial
RA and microvascular integrity on day 2 enables precise determination of the
efficacy of reperfusion therapy and prediction of the short- and intermediate
term prognoses of patients with recanalized MI.
PMID- 9768709
TI - Assessment of "microvascular no-reflow phenomenon" using technetium-99m
macroaggregated albumin scintigraphy in patients with acute myocardial
infarction.
AB - OBJECTIVES: The aim of this study was the scintigraphic evaluation of clinical no
reflow phenomenon. BACKGROUND: In patients with acute myocardial infarction, the
relationship of the severity of reduction of microvascular reflow to the ischemia
time or to the secondary extension of myocardial necrosis is poorly understood,
and we accordingly conducted a scintigraphic evaluation of clinical no-reflow
phenomenon. METHODS: The group studied consisted of 25 consecutive patients with
their first acute myocardial infarction. After recanalization, each patient
received intracoronary injections of technetium-99m macroaggregated albumin
(MAA). RESULTS: Eight patients (32%) had absent tracer uptake (scintigraphic no
reflow phenomenon). Fourteen patients showed absent or moderately reduced MAA
uptake (group 1) and 11 showed slightly reduced or normal uptake (group 2). The
time to recanalization was significantly longer in group 1 than in group 2
(290.4+/-130.6 min vs. 1773+/-93.5 min; p=0.0238). In chronic phase, the thallium
201 (TI-201) defect score index was significantly larger (p < 0.01) and regional
ejection fraction was significantly lower (p < 0.01) in group 1 compared with
corresponding values in group 2. No significant deterioration from acute phase to
chronic phase in either TI-201 defect score index or regional ejection fraction
was found in either group (two-way repeated measures analysis of variance).
CONCLUSIONS: These findings suggest that scintigraphic noreflow phenomenon occurs
in a subgroup of patients without angiographic no-reflow phenomenon, that the
myocardial damage depends on the severity of microvascular damage and that
prolonged ischemia time may increase the likelihood of "microvascular no-reflow
phenomenon."
PMID- 9768710
TI - Does acute improvement of endothelial dysfunction in coronary artery disease
improve myocardial ischemia? A double-blind comparison of parenteral D- and L
arginine.
AB - OBJECTIVES: Parenteral L-arginine will improve myocardial ischemia in patients
with obstructive coronary artery disease. BACKGROUND: Endothelial dysfunction
causes coronary arterial constriction during stress, and L-arginine improves
endothelial dysfunction. METHODS: Twenty-two patients with stable coronary artery
disease and exercise-induced ST-segment depression underwent assessment of
forearm endothelial function with acetylcholine and symptom-limited treadmill
exercise testing during dextrose 5% infusion and after double-blind intravenous
administration of L- and D-arginine (5 mg/kg/min) for 20 min. RESULTS: Forearm
blood flow increased with both L- and D-arginine (33%+/-6% and 38%+/-7%,
respectively, p < 0.001). Acetylcholine-mediated forearm vasodilation also
improved with both L- and D-arginine (p < 0.0001). The magnitude of improvement
was similar with both enantiomers and was observed in patients throughout the
range of acetylcholine responses and cholesterol levels. Heart rate and blood
pressure at rest and during each stage of exercise and exercise duration remained
unchanged with L- and D-arginine compared to control. Ischemic threshold,
measured either as the rate-pressure product or the duration of exercise at the
onset of 1-mm ST-segment depression during exercise, also remained unchanged.
Serum arginine, insulin and prolactin levels (p < 0.01) increased with both
enantiomers. CONCLUSIONS: Parenteral arginine produces non-stereo-specific
peripheral vasodilation and improves endothelium-dependent vasodilation in
patients with stable coronary artery disease by stimulation of insulin-dependent
nitric oxide release or by nonenzymatic nitric oxide generation. Despite enhanced
endothelial function, there was no improvement in myocardial ischemia during
stress with either enantiomer. Whether parenteral arginine will be of therapeutic
benefit in acute coronary syndromes and oral arginine in myocardial ischemia
needs to be studied further.
PMID- 9768711
TI - Prognostic value of the amount of dysfunctional but viable myocardium in
revascularized patients with coronary artery disease and left ventricular
dysfunction. Investigators of this Multicenter Study.
AB - OBJECTIVES: The purpose of our study was to assess the prognostic importance of
the amount of dysfunctional but viable myocardium in revascularized patients with
coronary artery disease (CAD) and left ventricular (LV) dysfunction. BACKGROUND:
The amount of dysfunctional but viable myocardium predicts the functional
improvement after revascularization and may offer more precise risk
stratification of patients referred for bypass surgery or coronary angioplasty.
METHODS: Two hundred and seventy-four consecutive patients with CAD and LV
ejection fraction < or =40% underwent low-dose dobutamine echocardiography for
viability assessment. One hundred and thirty-three of them were revascularized
using either coronary artery bypass surgery (118 patients) or coronary
angioplasty (15 patients) and entered this study. To quantify the amount of
dysfunctional but viable myocardium, wall motion was scored using 16-segment
model. The dysfunctional segments were defined as viable if they exhibited
improvement in their thickening by at least 1 grade with dobutamine infusion. The
patients were followed up for a mean period of 20+/-12 months (range, 2 to 48)
for cardiac mortality and nonfatal cardiac events including myocardial
infarction, unstable angina pectoris requiring hospitalization and
hospitalization for heart failure. Standard follow-up echocardiography was
performed 3 to 6 months after revascularization. RESULTS: Twenty-nine patients
exhibited a large amount of dysfunctional but viable myocardium (> or =6
segments, group A), 60 patients had a small amount of dysfunctional but viable
myocardium (2 to 5 segments, group B) and 44 patients were found to have
dysfunctional myocardium irreversibly damaged (group C). Similar
prerevascularization LV ejection fractions of 35%+/-5%, 34%+/-4%, 36%+/-4% in
groups A, B and C increased to 47%+/-6% (p < 0.01 vs. baseline, p < 0.01 vs.
groups B and C), to 40%+/-5% (p < 0.01 vs. baseline) and to 37%+/-6% (p = NS vs
baseline), respectively, after revascularization. The greatest functional
improvement after revascularization in group A patients was accompanied by a
lower rate of cardiac events during follow-up (2 vs. 18 in group B, p < 0.05, and
vs. 17 in group C, p < 0.01) and better cardiac event-free survival according to
Kaplan-Meier survival analysis (p < 0.05 vs. groups B and C, respectively).
CONCLUSION: In revascularized patients with CAD and moderate or severe LV
dysfunction, the presence of a large amount of dysfunctional but viable
myocardium identifies patients with the best prognosis.
PMID- 9768712
TI - Myocardial viability during dobutamine echocardiography predicts survival in
patients with coronary artery disease and severe left ventricular systolic
dysfunction.
AB - OBJECTIVES: The purpose of this study was to assess whether the presence or
absence of myocardial viability during dobutamine echocardiography (DE) predicts
survival in patients with coronary artery disease (CAD) and severe left
ventricular (LV) dysfunction. BACKGROUND: In patients with CAD, the presence of
myocardial viability during DE identifies viable myocardium and predicts recovery
of LV systolic function after revascularization. However, there is little data on
the relation between myocardial viability and clinical outcome in patients with
CAD and severe LV dysfunction. METHODS: We studied 318 patients with CAD and a LV
ejection fraction (EF) < or =35% who underwent DE and were followed for 18+/-10
months. Patients were classified into four groups. Group I (n=85) consisted of
patients who had evidence of myocardial viability and subsequently underwent
revascularization. Group II (n=119) consisted of patients with myocardial
viability who did not undergo revascularization. Group III (n=30) consisted of
patients who did not have myocardial viability and underwent revascularization.
Finally, group IV (n=84) patients lacked myocardial viability and did not undergo
revascularization. RESULTS: The four groups had similar baseline characteristics
and rest LVEF. During follow-up there were 51 deaths (16%). The mortality rate
was 6% in group I, 20% in group II, 17% in group III and 20% in group TV (p=0.01,
group I vs. other groups). CONCLUSIONS: In patients with CAD and severe LV
dysfunction who demonstrated myocardial viability during DE, revascularization
improved survival compared with medical therapy.
PMID- 9768713
TI - Attenuation-corrected 99mTc-tetrofosmin single-photon emission computed
tomography in the detection of viable myocardium: comparison with positron
emission tomography using 18F-fluorodeoxyglucose.
AB - OBJECTIVES: The purpose of this study was to assess the efficacy of attenuation
corrected (AC) technetium-99m (99mTc)-tetrofosmin single-photon emission computed
tomography (SPECT) in detecting viable myocardium compared to 18F
fluorodeoxyglucose (FDG) positron emission tomography (PET). BACKGROUND: The role
of 99mTc-labeled perfusion tracers in the assessment of myocardial viability
remains controversial. Attenuation artifacts affect the diagnostic accuracy of
SPECT images. METHODS: Twenty-four patients with coronary artery disease (mean
left ventricular ejection fraction 30%) underwent resting 99mTc-tetrofosmin SPECT
and FDG PET imaging. Both AC and non-attenuation-corrected (NC) SPECT images were
generated. RESULTS: Using a 50% threshold for viability by FDG PET, the
percentage of concordant segments of viability between 99mTc-tetrofosmin and FDG
on the patient basis increased from 79.8%+/-14.0% (mean+/-SD) on the NC images to
90.8%+/-10.6% on the AC images (p=0.002). The percentage of 99mTc-tetrofosmin
defect segments within PET-viable segments, an estimate for the degree of
underestimation of viability, decreased from 19.8%+/-15.2% on the NC images to
9.7%+/-12.6% on the AC images (p=0.01). Similar results were obtained when a 60%
threshold was used to define viability by FDG PET. When the anterior-lateral and
inferior-septal regions were separately analyzed, the effect of attenuation
correction was significant only in the inferior-septal region. CONCLUSIONS: The
results indicate that AC 99mTc-tetrofosmin SPECT improves the detection of viable
myocardium mainly by decreasing the underestimation of viability particularly in
the inferior-septal region, although some underestimation/overestimation of
viability may still occur even with attenuation correction.
PMID- 9768714
TI - Prognostic value of congestive heart failure history in patients undergoing
percutaneous coronary interventions.
AB - OBJECTIVES: We sought to determine the prognostic significance of a history of
congestive heart failure above that provided by baseline ejection fraction in
patients undergoing percutaneous coronary interventions. BACKGROUND: Left
ventricular function is a known predictor of survival in patients with coronary
artery disease, as is a history of congestive heart failure. The contribution of
heart failure history independent of left ventricular function is unknown.
METHODS: Data were pooled from four interventional trials and the Duke University
database. The combined dataset included 5,260 patients undergoing percutaneous
interventions, 334 with and 4,926 without a history of heart failure. Patients
were defined by the treating physician as having a clinical history of heart
failure at the time of enrollment. RESULTS: The 30-day and 6-month mortality were
higher in patients with a clinical history of congestive heart failure than in
those without such a history (2% vs. <1%, p=0.002 at 30 days, 5% vs. 1%, p=0.001
at 6 months). Heart failure history did not influence the incidence of myocardial
infarction, use of angioplasty or the use of bypass surgery during follow-up.
Multivariable analysis revealed that heart failure history added significantly to
ejection fraction in predicting intermediate-term (6-month) mortality (p=0.01).
Stepwise logistic regression also revealed heart failure history to be an
independent predictor of 6-month mortality (odds risk 1.9, 95% confidence
interval 1.1 to 3.5). CONCLUSIONS: A clinical history of congestive heart failure
is associated with increased early and intermediate-term mortality in patients
undergoing percutaneous revascularization. Congestive heart failure history
appears to provide prognostic information independent of that available from a
patient's left ventricular function. These findings suggest that patients with a
clinical history of congestive heart failure who undergo a percutaneous
intervention should be closely monitored, especially those with the lowest
ejection fractions.
PMID- 9768715
TI - Prevalence and significance of nonsustained ventricular tachycardia in patients
with premature ventricular contractions and heart failure treated with
vasodilator therapy. Department of Veterans Affairs CHF STAT Investigators.
AB - OBJECTIVES: This study sought to determine the prevalence and significance of
nonsustained ventricular tachycardia (NSVT) in patients with premature
ventricular contractions (PVCs) and heart failure treated with vasodilator
therapy. BACKGROUND: Heart failure patients with ventricular arrhythmia and NSVT
have a significantly increased risk of premature cardiac death. Recently there
has been the question of whether these arrhythmias are expressions of a severely
compromised ventricle or are they independent risk factors. We, therefore,
determined the prevalence and significance of NSVT in patients with PVCs and
heart failure and on vasodilator therapy. METHODS: Twenty-four hour ambulatory
recordings were done at randomization, at 2 weeks, at months 1, 3, 6, 9 and 12
and then every 6 months in 674 patients with heart failure and on vasodilator
therapy. The median period of follow-up was 45 months (range 0 to 54). RESULTS:
Nonsustained ventricular tachycardia was present in 80% of all patients. Patients
without (group 1) and with (group 2) NSVT were balanced for variables: age,
etiology of heart disease, New York Heart Association (NYHA) functional class,
use of amiodarone and diuretics and left ventricular diameter by echocardiogram.
However, group 1 patients had significantly less beta-adrenergic blocking agent
use and higher ejection fraction (EF) (p < 0.002 and p < 0.001, respectively).
Survival analysis for all deaths showed a greater risk of death among group 2
patients (p=0.01). Similarly, sudden death was increased in group 2 patients
(p=0.02, risk ratio 1.8). After adjusting for the above variables, only EF
(p=0.001) and NYHA class (p=0.01) were shown to be independent predictors of
survival. Nonsustained ventricular tachycardia showed a trend (p=0.07) as an
independent predictor for all-cause mortality but not for sudden death. Only EF
was an independent predictor for sudden death. CONCLUSIONS: Nonsustained
ventricular tachycardia is frequently seen in patients with heart failure and may
be associated with worsened survival by univariate analysis. However, after
adjusting other variables, especially for EF, NSVT was not an independent
predictor of all-cause mortality or sudden death. These results have serious
implications in that suppression of these arrhythmias may not improve survival.
PMID- 9768716
TI - Right ventricular ejection fraction is an independent predictor of survival in
patients with moderate heart failure.
AB - OBJECTIVES: We sought to study the relationship between survival and right
ventricular ejection fraction (RVEF) in a subgroup of patients with moderate
congestive heart failure (CHF). BACKGROUND: It has been demonstrated that RVEF is
an independent predictor of survival in patients with advanced CHF. METHODS:
Cardiopulmonary exercise testing and radionuclide angiography (to determine right
and left ventricular ejection fraction) were prospectively performed in 205
consecutive patients with moderate CHF (140 patients in New York Heart
Association [NYHA] class II, 65 in class III). RESULTS: Left ventricular ejection
fraction was 29.3%+/-10.1%, RVEF was 37.5%+/-14.6% and peak oxygen consumption
(VO2) was 16.2+/-5.4 ml/min/kg (60.2%+/-19% of maximal predicted VO2). After a
median follow-up period of 755 days, there were 44 cardiac-related deaths, 3
deaths from noncardiac causes and 15 transplantations of whom 2 were urgent; 1
patient was lost to follow-up. Multivariate analysis showed that three variables
NYHA classification, percent of maximal predicted VO2 and RVEF-were independent
predictors of both survival and event-free cardiac survival. Left ventricular
ejection fraction and peak VO2 normalized to body weight had no predictive value.
The event-free survival rates from cardiovascular mortality and urgent
transplantation at 1 year were 80%, 90% and 95% in patients with an RVEF <25%,
with a RVEF > or =25% and <35% and with a RVEF > or =35%, respectively. At 2
years, survival rates were 59%, 77% and 93% in the same subgroups, respectively.
CONCLUSIONS: In addition to the NYHA classification and to the percent of maximal
predicted VO2, RVEF is an independent predictor of survival in patients with
moderate CHF.
PMID- 9768717
TI - Expression, activity and functional significance of inducible nitric oxide
synthase in the failing human heart.
AB - OBJECTIVES: The study was designed to evaluate the functional impact of nitric
oxide (NO) generation within the myocardium on cardiac contraction in the failing
human heart. BACKGROUND: Heart failure is associated with activation of cytokines
and expression of inducible nitric oxide synthase (NOS II), which generates NO
from L-arginine. Nitric oxide has been shown to modulate myocardial performance,
raising the possibility that cardiac generation of NO by NOS II modulates cardiac
contraction in the failing human heart. METHODS: Left ventricular (LV) tissue of
24 patients with end-stage heart failure was obtained during cardiac
transplantation. Gene expression of NOS II and endothelial NO-synthase (NOS III)
was quantified by competitive reverse transcription-polymerase chain reaction and
compared to tissues of five nonfailing donor hearts. Nitric oxide synthase II
activity was determined by citrulline assay and related to changes in force of
contraction induced by the beta-adrenergic agonist isoproterenol, NO-donors
and/or N-mono-methyl-L-arginine (L-NMMA), an inhibitor of NOS. RESULTS: While NOS
III mRNA was reduced in failing hearts, NOS II mRNA was increased in failing LV
tissue and correlated with NOS II activity. High NOS II activity was associated
with early relaxation and impaired responsiveness to beta-adrenergic stimulation,
that is, the inotropic response to isoproterenol in failing hearts was inversely
related to NOS II activity (r=0.61, p < 0.005). Nitric oxide donors or L-NMMA did
not affect myocardial performance in failing hearts at baseline. However, L-NMMA
enhanced the positive inotropic response to beta-adrenergic stimulation in
failing hearts with high NOS II activity. Nitric oxide donors attenuated the
isoproterenol-induced increase in force of contraction of failing hearts.
CONCLUSIONS: Cardiac production of NO by NOS II attenuates the positive inotropic
effects of beta-adrenergic stimulation and hastens relaxation in failing human
hearts.
PMID- 9768718
TI - Inducible nitric oxide synthase in skeletal muscle of patients with chronic heart
failure.
AB - OBJECTIVES: The expression and localization of inducible nitric oxide (NO)
synthase (NOS II) was evaluated as a source of NO which has been shown to affect
muscle contraction. BACKGROUND: Advanced stages of chronic heart failure are
associated with systemic activation of cytokines which have been shown to
stimulate the expression of NOS II in various cell types, including myocytes. We
hypothesized that systemic cytokine activation could lead to expression of NOS II
in skeletal muscle of patients with chronic heart failure. METHODS: Skeletal
muscle specimens were obtained by percutaneous needle biopsy in six normal
volunteers and eight patients with heart failure (New York Heart Association
class III). Electron microscopy immunocytochemistry (immunogold labeling) with
specific anti-NOS antibodies was utilized to elucidate the intracellular
localization of NOS II and neuronal NO synthase (NOS I) in myocytes of skeletal
muscle. Reverse transcriptase, competitive polymerase chain reaction (PCR) was
applied to quantify NOS II mRNA in skeletal muscle. RESULTS: Inducible nitric
oxide synthase was readily expressed in the cytosol of skeletal muscle myocytes;
NOS I expression was sparse. Polymerase chain reaction results indicated that NOS
II gene expression is increased in patients with chronic heart failure.
CONCLUSIONS: Inducible NO synthase is expressed in human skeletal muscle and its
gene expression is increased in patients with severe heart failure. Given the
experimental evidence that NO can attenuate contractile performance of skeletal
muscle and can mediate muscle wasting, an increased local production of NO in
skeletal muscle by NOS II may have important implications for patients with
severe heart failure.
PMID- 9768719
TI - Operator volume and outcome of patients undergoing coronary stent placement.
AB - OBJECTIVES: The aim of this study was to assess the relation between operator
experience in coronary stent placement procedures and the clinical outcome of
patients. BACKGROUND: The results of coronary balloon angioplasty are closely
related to the experience of the operator performing the procedure. Data on the
effect of operator experience on the results after coronary stent placement are
missing. METHODS: The study included 3,409 consecutive patients undergoing
coronary stent placement for the management of coronary artery disease. A
composite end point of cardiac death, myocardial infarction and aortocoronary
bypass surgery during the first 30 days after the intervention, was the primary
end point and the procedural failure was the secondary end point of the study.
RESULTS: Adverse clinical outcome occurred in 2.99% of the 3,409 patients
undergoing coronary stent placement. Procedural failure was recorded in 2.08% of
the patients. Operator volumes above 483 procedures were associated with a risk
adjusted adverse outcome rate of 1.70%+/-1.28%, which is significantly lower than
the overall rate of 2.99%. Operator yearly volumes of under 90 procedures were
associated with a risk-adjusted adverse outcome rate of 4.59%+/-1.17%, which is
significantly higher than the overall rate of 2.99%. The operator experience was
an independent predictor even after adjusting for the effect of other risk
factors. The analysis demonstrated that an experience of at least 100 procedures
is required to obtain better outcome even in patients with simple coronary
lesions and that operators should perform at least 70 procedures annually to
expect a better outcome in patients with both simple and complex coronary
lesions. CONCLUSIONS: Operator experience is a significant and independent
predictor of the outcome of patients undergoing coronary stent placement. An
experience of at least 100 procedures and an annual volume of at least 70
procedures are required to ensure a significantly better outcome after coronary
stent implantation.
PMID- 9768720
TI - Stents: expanding the case for volume minimums in interventional cardiology.
PMID- 9768721
TI - Balloon angioplasty for the treatment of coronary in-stent restenosis: immediate
results and 6-month angiographic recurrent restenosis rate.
AB - OBJECTIVES: The purpose of this prospective study was to evaluate the immediate
results and the 6-month angiographic recurrent restenosis rate after balloon
angioplasty for in-stent restenosis. BACKGROUND: Despite excellent immediate and
mid-term results, 20% to 30% of patients with coronary stent implantation will
present an angiographic restenosis and may require additional treatment. The
optimal treatment for in-stent restenosis is still unclear. METHODS: Quantitative
coronary angiography (QCA) analyses were performed before and after stent
implantation, before and after balloon angioplasty for in-stent restenosis and on
a 6-month systematic coronary angiogram to assess the recurrent angiographic
restenosis rate. RESULTS: Balloon angioplasty was performed in 52 patients
presenting in-stent restenosis. In-stent restenosis was either diffuse (> or =10
mm) inside the stent (71%) or focal (29%). Mean stent length was 16+/-7 mm.
Balloon diameter of 2.98+/-0.37 mm and maximal inflation pressure of 10+/-3 atm
were used for balloon angioplasty. Angiographic success rate was 100% without any
complication. Acute gain was lower after balloon angioplasty for in-stent
restenosis than after stent implantation: 1.19+/-0.60 mm vs. 1.75+/-0.68 mm
(p=0.0002). At 6-month follow-up, 60% of patients were asymptomatic and no
patient died. Eighteen patients (35%) had repeat target vessel revascularization.
Angiographic restenosis rate was 54%. Recurrent restenosis rate was higher when
in-stent restenosis was diffuse: 63% vs. 31% when focal, p=0.046. CONCLUSIONS:
Although balloon angioplasty for in-stent restenosis can be safely and
successfully performed, it leads to less immediate stenosis improvement than at
time of stent implantation and carries a high recurrent angiographic restenosis
rate at 6 months, in particular in diffuse in-stent restenosis lesions.
PMID- 9768722
TI - Relations between cardiac and vascular structure in patients with primary and
secondary hypertension.
AB - BACKGROUND: Data on cardiac and vascular structure in secondary hypertension are
generally scarce, and no data on the interrelations between cardiac mass and
structural characteristics of the vessel wall, both in large and in small
resistance arteries, are presently available. OBJECTIVES: The aim of this study
was to investigate the relation between structural changes in subcutaneous small
arteries, left ventricular mass and wall thickness of the common carotid artery
in patients with primary and secondary hypertension. METHODS: Seventy-four
subjects were included in the study: 11 patients with pheochromocytoma, 14 with
primary aldosteronism (PA), 19 with renovascular hypertension (RVH), 18 with
essential hypertension (EH) and 12 normotensive (NT) control subjects. All
subjects were submitted to a biopsy of subcutaneous fat. Morphologic
characteristics of subcutaneous small resistance arteries (relaxed diameter <300
microm) were directly evaluated using a micromyographic technique. All subjects
were submitted to calculation of left ventricular mass index (LVMI) and common
carotid artery intima-media thickness (CCIMT), using ultrasound technique.
RESULTS: The correlation coefficients between the media to lumen ratio in
subcutaneous small arteries (M/L) and LVMI or between M/L and CCIMT were closer
in RVH than in pheochromocytoma, EH or NT; in PA the correlation coefficients
were slightly less close than those in RVH. An excess prevalence of carotid
plaques in RVH was observed. CONCLUSIONS: A close relation between small
resistance artery morphology and cardiac or carotid artery structure may be
observed in those hypertensive patients in whom the renin-angiotensin-aldosterone
system is activated. In constrast, in NT, EH and pheochromocytoma no significant
correlation between M/L and LVMI or CCIMT was observed.
PMID- 9768723
TI - The effects of New York's bypass surgery provider profiling on access to care and
patient outcomes in the elderly.
AB - OBJECTIVE: The aim of this study was to examine the effects of provider profiling
on bypass surgery access and outcomes in elderly patients in New York.
BACKGROUND: Since 1989, New York (NY) has compiled provider-specific bypass
surgery mortality reports. While some have proposed that "provider profiling" has
led to lower surgical mortality rates, critics have suggested that such programs
lower in-state procedural access (increasing out-of-state transfers) without
improving patient outcomes. METHODS: Using national Medicare data, we examined
trends in the percentages of NY residents aged 65 years or older receiving out-of
state bypass surgery between 1987 and 1992 (before and after program initiation).
We also examined in-state procedure use among elderly myocardial infarction
patients during this period. Finally, we compared trends in surgical outcomes in
NY Medicare patients with those for the rest of the nation. RESULTS: Between 1987
and 1992, the percentage of NY residents receiving bypass out-of-state actually
declined (from 12.5% to 11.3%, p < 0.01 for trend). An elderly patient's
likelihood for bypass following myocardial infarction in NY increased
significantly since the program's initiation. Between 1987 and 1992, unadjusted
30-day mortality rates following bypass declined by 33% in NY Medicare patients
compared with a 19% decline nationwide (p < 0.001). As a result of this
improvement, NY had the lowest risk-adjusted bypass mortality rate of any state
in 1992. CONCLUSIONS: We found no evidence that NY's provider profiling limited
procedure access in NY's elderly or increased out-of-state transfers. Despite an
increasing preoperative risk profile, procedural outcomes in NY improved
significantly faster than the national average.
PMID- 9768724
TI - How do we know how well we are doing?
PMID- 9768725
TI - Hemodynamic performance of cryopreserved aortic homograft valves during midterm
follow-up.
AB - OBJECTIVES: The aim of this prospective study of adult patients operated with a
cryopreserved aortic homograft was to use serial echocardiographic data to
evaluate the postoperative hemodynamic performance of these valves. BACKGROUND:
Only limited data on hemodynamic performance of aortic homografts at rest and
during exercise are available. Controversy also exists regarding incidence and
progression of aortic regurgitation (AR). METHODS: Fifty-nine patients aged 39-86
years who received an aortic homograft (median size 21 mm) implanted with
subcoronary technique were studied with serial Doppler-echocardiography (D-E). In
31 of these patients, D-E also was performed during supine exercise. RESULTS:
Overall survival was 100% during a median follow-up of 28 months (range 4-54).
During follow-up AR grade II or more was detected in 25% of the patients with an
increasing time-related risk of developing AR. Maximum and mean pressure
differences at 7 months follow-up calculated with the short form of the Bernoulli
equation were 11.4 (4.6) and 5.5 (2.1) mm Hg, respectively. During supine
exercise that increased cardiac output 72%, maximum pressure difference increased
from 11.9 (5.2) to 18.5 (9.5) mm Hg. CONCLUSIONS: The aortic homograft valve
shows low pressure differences at rest and during exercise, but AR grade I or II
is often seen during follow-up. As AR progresses with time we stress the
importance of echocardiographic follow-up of patients with aortic homografts.
PMID- 9768726
TI - Retrograde nontransseptal balloon mitral valvuloplasty: immediate results and
intermediate long-term outcome in 441 cases--a multicenter experience.
AB - OBJECTIVES: Our aim was to present the immediate and intermediate long-term
results of the application of retrograde nontransseptal balloon mitral
valvuloplasty (RNBMV) in four cooperating centers from Greece and India.
BACKGROUND: RNBMV is a purely transarterial method of balloon valvuloplasty,
developed with the aim to avoid complications associated with transseptal
catheterization. Only single-center experience with RNBMV has been previously
reported. METHODS: The procedure was attempted in 441 patients with symptomatic
mitral stenosis (320 women, 121 men, mean age [+/-SD] 44+/-11 years, mean
echocardiographic score [+/-SD] 7.7+/-2.0) from 1988 to 1996. Three hundred
eighty-five patients with successful immediate outcome were followed clinically
for a mean [+/-SD] of 3.5+/-1.9 (range, 0.5-9.1) years. RESULTS: A technically
successful procedure was achieved in 388 (88%) cases. The echocardiographic score
(p < 0.001), male gender (p=0.005), preprocedural mitral regurgitation (p=0.007)
and previous surgical commissurotomy (p=0.029) were unfavorable predictors of
immediate outcome. Complications included death (0.2%), severe mitral
regurgitation (3.4%) and injury of the femoral artery (1.1%). Event-free (freedom
from cardiac death, mitral valve surgery, repeat valvuloplasty and NYHA class >
II symptoms) survival rates (+/-SEM) were 100%, 96.9+/-0.9%, 89.8+/-1.9% and
75.5+/-5.5% at 1, 2, 4 and 9 years, respectively. The echocardiographic score (p
< 0.001), NYHA class (p=0.008) and postprocedural mitral valve area (p=0.009)
were significant independent predictors of intermediate long-term outcome.
CONCLUSIONS: Multicenter experience indicates that RNBMV is a safe and effective
technique for the treatment of symptomatic mitral stenosis. As with the
transseptal approach, patients with favorable mitral valve anatomy derive the
greatest immediate and intermediate long-term benefit from this procedure.
PMID- 9768727
TI - Echocardiographic and biochemical evaluation of the development and progression
of carcinoid heart disease.
AB - OBJECTIVES: To study the applicability of a newly developed echocardiographic
scoring system in the assessment of carcinoid valvular heart disease. BACKGROUND:
We investigated prospectively the development, progression and regression of
carcinoid valvular heart disease in patients with carcinoid syndrome by serial
echocardiography, correlating these features with urinary 5-HIAA levels and
clinical data collected during therapy with somatostatin analog. METHODS: Twenty
three patients with carcinoid syndrome underwent serial echocardiographic
examinations. An echocardiographic carcinoid valvular heart disease (CVHD) %
score was determined from points assigned for tricuspid and pulmonary valve
structure and function. RESULTS: Fifteen patients had no CVHD at study entry
(group 1), while 8 patients had findings of CVHD (group 2). Five patients in
group q developed new CVHD (1B), while one demonstrated progression of CVHD (2B).
The remaining patients did not develop (1A) or had no progression of CVHD (2B).
Despite major declines in 5-HIAA levels during therapy in most patients, CVHD did
not regress. There were significantly lower levels of median baseline 5-HIAA
(98.8 vs. 256 mg/24 h), posttreatment 5-HIAA (50.3 vs. 324 mg/24 h) and
posttreatment 5-HIAA time integral (37.3 vs. 192 g/24 h* days) in group A vs. B
(p < 0.05). However, only posttreatment 5-HIAA levels independently predicted the
development or progression of CVHD by multiple step-wise regression analysis (p <
0.005), with a threshold observed in the 100 mg/24 h range. CONCLUSIONS: We
designed a new echocardiographic scoring system to evaluate CVHD. Correlating
echocardiographic scores with biochemical and clinical markers showed that only
posttreatment 5-HIAA levels independently predicted the development or
progression of CVHD. This study strengthens the association between serotonin
secretion and CVHD, as well as introducing a new technique for serial follow-up
of these patients.
PMID- 9768728
TI - Tricuspid valve surgery and intraoperative echocardiography: factors affecting
survival, clinical outcome, and echocardiographic success.
AB - BACKGROUND: The impact of echocardiographic-guided treatment on outcome after
tricuspid valve (TV) surgery is not well defined. OBJECTIVES: The purpose of this
study was to determine clinical and echocardiographic factors associated with
adverse outcomes after TV surgery and determine the role of intraoperative echo
(IOE) in facilitating successful outcomes after TV surgery. METHODS: Four hundred
and one patients (279 females, mean age 60 years) underwent TV surgery and other
concomitant cardiac surgery at a single institution and were followed clinically
and by echocardiography during a 10-year period. RESULTS: Decreased survival
after TV surgery was associated with: preoperative increased New York Heart
Association (NYHA) functional classification (relative risk [RR]=2.02), increased
left ventricular dysfunction by echocardiography (RR=1.28), and use of a TV
replacement strategy (RR=2.92). Decreased event-free survival after TV surgery
was associated with concomitant coronary artery bypass grafting (RR=2.97). Late
echocardiographic failure (3 to 4+ tricuspid valve regurgitation [TR]) after TV
surgery was associated with increased severity of TR on preoperative
echocardiogram (odds ratio [OR]=1.91). Decreased late echocardiographic failure
after TV surgery was associated with the use of a TV annuloplasty ring with a
repair strategy (OR=0.40). The surgical plan was altered at the time of surgery
to insure a successful outcome in 32 (10%) of 335 patients based on IOE findings.
CONCLUSIONS: Adverse outcomes after TV surgery can be predicted by several
preoperative clinical and echocardiographic variables. IOE is useful in improving
immediate, but not late, outcomes after TV surgery.
PMID- 9768729
TI - Application of the proximal flow convergence method to calculate the effective
regurgitant orifice area in aortic regurgitation.
AB - OBJECTIVES: We sought to determine the reliability of the proximal isovelocity
surface area (PISA) method for calculation of effective regurgitant orifice (ERO)
of aortic regurgitation (AR). BACKGROUND: The ERO area can be calculated by the
PISA method, but this method has not been validated in AR. METHODS: ERO
calculation by the PISA method was undertaken prospectively in 71 consecutive
patients with isolated AR and achieved in 64 and compared with two simultaneous
reference methods (quantitative Doppler and quantitative two-dimensional
echocardiography). In addition, this method was compared with angiography in 12
patients, with surgical assessment in 18 patients and with ventricular volumes in
all patients. RESULTS: Good correlations between PISA and reference methods were
obtained (both r=0.90, both p < 0.0001), but a trend toward underestimation of
the ERO by the PISA method was noted (24+/-19 vs. 26+/-22 mm2 and 27+/-23 mm2,
respectively, both p=0.04). However, this trend was confined to five patients
with an obtuse flow convergence angle (>220 degrees), and on multivariate
analysis this variable was the only independent determinant of underestimation of
the ERO. In contrast, in 59 patients with a flat flow convergence (< or =220
degrees ), the PISA method, in comparison with reference methods, showed
excellent correlations, with a narrow standard error of the estimate (r=0.95, SEE
5.4 mm2, and r=0.95, SEE 5.8 mm2; all p < 0.0001) and no trend toward
underestimation (22+/-18 vs. 23+/-16 mm2, p=0.44, and vs. 23+/-18 mm2, p=0.34).
CONCLUSIONS: In patients with AR, the PISA method can be used to measure the ERO
with reasonable feasibility. Underestimation of the ERO by PISA may occur in
patients with an obtuse flow convergence angle. However, in most patients with
appropriate flow convergence, PISA provides reliable measurement of the ERO of
AR.
PMID- 9768730
TI - Transient sinus node dysfunction after the Cox-maze III procedure in patients
with organic heart disease and chronic fixed atrial fibrillation.
AB - OBJECTIVES: This prospective study examined types, frequency and time dependency
of the electrophysiologic manifestation of the sinus node dysfunction after the
Cox-maze III procedure--the technique of choice for the management of medically
refractory atrial fibrillation-in patients with organic heart disease, chronic
fixed atrial fibrillation and no preoperatively overt dysfunction of the sinus
node. BACKGROUND: The original maze procedure was modified twice in order to
reduce the high incidence of the sinus node inability to generate an appropriate
sinus tachycardia in response to maximal exercise, and occasional left atrial
dysfunction. Despite these modifications, postoperative disturbance of sinus node
function can be frequently observed. METHODS: In 15 adult patients, standard
electrocardiogram, 24-h Holter monitoring, power spectral analysis of heart
variability, exercise testing, Valsalva maneuver and rapid positional changes
were performed 3, 6 and 12 months after the Cox-maze III procedure and mitral
valve surgery or closure of atrial septal defect. RESULTS: Electrocardiographic
manifestations of sinus node dysfunction were identified in 12 patients at 3
months, in 6 patients at 6 months, and in 0 patients at 12 months after surgery.
The heart rate response to exercise during the first 6 months was reduced in the
maze group and became fully normal at 12 months. Power spectral analysis of heart
rate variability showed very low power values at 1 month with inhibited cardiac
autonomic activity and no response on sympathetic stress. A potential of recovery
of cardiac autonomic activity was documented 12 months after surgery.
CONCLUSIONS: The manifestations of sinus node dysfunction following the Cox-maze
III procedure were time dependent and their frequency and intensity progressively
decreased and disappeared within 12 months after surgery.
PMID- 9768731
TI - Catheter ablation of atrioatrial conduction as a cure for atrial arrhythmia after
orthotopic heart transplantation.
AB - OBJECTIVES: We present three patients in whom atrial arrhythmia was treated by
ablation of electrical conduction across a surgical suture line. BACKGROUND:
Conduction across the suture line separating the donor and native right atria has
recently been described after orthotopic heart transplantation. METHODS: Mapping
and pacing of both grafted and recipient right atrium was performed to assess the
relation between both atria and its relevance to clinical arrhythmia, prior to
successful radiofrequency at the site of electrical communication. RESULTS: In
cases 1 and 3, atrioatrial conduction was bidirectional. In both, two types of P
waves were observed during sinus rhythm. In case 2, conduction from the recipient
to the grafted atrium yielded a very particular surface ECG pattern of atrial
extrasystole. The block being unidirectional, the recipient atrial sinus rhythm
was not perturbed and behaved like an atrial parasystole. Ablation was performed
during sinus rhythm in case 1, recipient right atrial pacing in case 2 and
grafted right atrial pacing in case 3 at the site with the shortest conduction
time to the other tissue. At the successful ablation site multiple component
potentials were recorded. Respectively, 1, 4 and 2 radiofrequency pulses were
followed by total atrioatrial conduction interruption. No tachycardia could be
induced at the end of the procedure and late follow-up was event free.
CONCLUSIONS: The existence of arrhythmogenic atrioatrial conduction should be
taken into account when evaluating atrial arrhythmias in the transplanted heart
because it is potentially curable by radiofrequency catheter ablation.
PMID- 9768732
TI - Cardiac death and stored electrograms in patients with third-generation
implantable cardioverter-defibrillators.
AB - OBJECTIVES: We sought to utilize terminal stored intracardiac electrograms (EGMs)
to study the electrophysiologic events that accompany mortality in patients with
third-generation implantable cardioverter-defibrillators (ICDs). BACKGROUND:
Despite their ability to effectively terminate ventricular tachyarrhythmias,
cardiac mortality in patients with ICDs remains high. The mechanisms and modes of
death in these patients are not well understood. METHODS: We retrospectively
analyzed clinical data and stored EGMs from patients enrolled in the clinical
trial of the Ventritex Cadence ICD. Of the 1,729 patients 119 died during 6 years
of follow-up. The final recorded EGM was reviewed. Postimplant EGMs as well as 50
control EGMs were used to define normal EGM characteristics. RESULTS: There were
36 noncardiac deaths (30%) and 83 cardiac deaths (70%). Of the cardiac deaths, 55
(66%) were nonsudden and 28 (34%) were sudden. When cardiac deaths were analyzed,
46 (55%) had no stored EGMs within 1 h of death, implying that the deaths were
not directly related to tachyarrhythmias. In 37 cardiac deaths (18 nonsudden, 19
sudden), stored EGMs were present within 1 h of death. In these 37 deaths, the
final EGM recorded was wide (>158 ms) in 33 (89%). Wide EGMs were interpreted as
ventricular tachycardia in 27 and ventricular fibrillation in 6. In 13 of the 33
patients (39%) with wide EGMs, therapy was not delivered by the ICD, as it
incorrectly detected a spontaneous termination of the arrhythmia. EGMs were
significantly wider if recorded within 1 h, as compared with those recorded from
1 to 48 h before death (261+/-124 vs. 181+/-93 ms, p=0.04). CONCLUSIONS: Only 37
patients (31%) who died after placement of an ICD had a stored EGM within 1 h of
the time of death, suggesting that the majority of deaths (69%) were not the
immediate result of a tachyarrhythmia. When EGMs were recorded, they were wide in
89% of patients. These wide EGMs most likely represent intracardiac recordings of
electromechanical dissociation. Thus, of the 119 deaths, 112 (94%) were not the
immediate result of a tachyarrhythmia.
PMID- 9768733
TI - Amiodarone reduces transmural heterogeneity of repolarization in the human heart.
AB - OBJECTIVES: The present work was designed to test the effects of amiodarone
therapy on action potential characteristics of the three cell types observed in
human left ventricular preparations. BACKGROUND: The electrophysiologic basis for
amiodarone's exceptional antiarrhythmic efficacy and low proarrhythmic profile
remains unclear. METHODS: We used standard microelectrode techniques to
investigate the effects of chronic amiodarone therapy on transmembrane activity
of the three predominant cellular subtypes (epicardial, midmyocardial [M] and
endocardial cells) spanning the human left ventricle in hearts explanted from
normal, heart failure and amiodarone-treated heart failure patients. RESULTS:
Tissues isolated from the ventricles of heart failure patients receiving chronic
amiodarone therapy displayed M cell action potential duration (404+/-12 ms)
significantly briefer (p < 0.05) than that recorded in tissues isolated from
normal hearts (439+/-22 ms) or from heart failure patients not treated with
amiodarone (449+/-18 ms). Endocardial cells from amiodarone-treated heart failure
patients displayed longer (p < 0.05) action potential duration (363+/-10 ms) than
endocardial cells isolated from normal hearts (330+/-6 ms). As a consequence, the
heterogeneity of ventricular repolarization in tissues from patients treated with
amiodarone was considerably smaller than in the two other groups, especially at
long pacing cycle lengths. CONCLUSIONS: These findings may explain, at least in
part, the reduction of ventricular repolarization dispersion and the lower
incidence of torsade de pointes observed with chronic amiodarone therapy as
compared with other class III agents.
PMID- 9768734
TI - Inhaled nitric oxide in primary pulmonary hypertension: a safe and effective
agent for predicting response to nifedipine.
AB - OBJECTIVES: The purpose of this study was to assess the utility of inhaled nitric
oxide (NO), a selective pulmonary vasodilator, for predicting the safety and
acute hemodynamic response to high-dose oral nifedipine in primary pulmonary
hypertension (PPH). BACKGROUND: A significant decrease in pulmonary vascular
resistance with an oral nifedipine challenge is predictive of an improved
prognosis, and potential clinical efficacy in PPH. However, the required
nifedipine trial carries significant first-dose risk of hypotension. While
inhaled NO has been recommended for assessing pulmonary vasodilator reserve in
PPH, it is not known whether it predicts the response to nifedipine. METHODS:
Seventeen patients with PPH undergoing a nifedipine trial were assessed for
hemodynamic response to inhaled NO at 80 parts per million for 5 minutes. The
nifedipine trial consisted of 20 mg of nifedipine hourly for 8 hours unless
limited by hypotension or intolerable side effects. Patients were classified as
responders and nonresponders with positive response defined as > or =20%
reduction in mean pulmonary artery pressure (mPA) or pulmonary vascular
resistance (PVR) with the vasodilator administration. RESULTS: NO was safely
administered to all participants. Seven of 17 (41.2%) responded to NO, and 8 of
the 17 to nifedipine (47.1%). Nifedipine was safely administered in 14 of the 17.
Three suffered either mild or severe hypotension, including one death. All NO
responders also responded to nifedipine, and 9 of the 10 NO nonresponders were
nifedipine nonresponders, representing a sensitivity of 87.5%, specificity of
100%, and overall predictive accuracy of 94%. All NO responders tolerated a full
nifedipine trial without hypotension. There was a highly significant correlation
between the effects of NO and nifedipine on PVR (r=0.67, p=0.003). CONCLUSIONS:
The pulmonary vascular response to inhaled NO accurately predicts the acute
hemodynamic response to nifedipine in PPH, and a positive response to NO is
associated with a safe nifedipine trial. In patients comparable with those
evaluated, a trial of nifedipine in NO nonresponders appears unwarranted and
potentially dangerous.
PMID- 9768735
TI - Quantification of mitral regurgitation by automated cardiac output measurement:
experimental and clinical validation.
AB - OBJECTIVES: To develop and validate an automated noninvasive method to quantify
mitral regurgitation. BACKGROUND: Automated cardiac output measurement (ACM),
which integrates digital color Doppler velocities in space and in time, has been
validated for the left ventricular (LV) outflow tract but has not been tested for
the LV inflow tract or to assess mitral regurgitation (MR). METHODS: First, to
validate ACM against a gold standard (ultrasonic flow meter), 8 dogs were studied
at 40 different stages of cardiac output (CO). Second, to compare ACM to the LV
outflow (ACMa) and inflow (ACMm) tracts, 50 normal volunteers without MR or
aortic regurgitation (44+/-5 years, 31 male) were studied. Third, to compare ACM
with the standard pulsed Doppler-two-dimensional echocardiographic (PD-2D) method
for quantification of MR, 51 patients (61+/-14 years, 30 male) with MR were
studied. RESULTS: In the canine studies, CO by ACM (1.32+/-0.3 liter/min, y) and
flow meter (1.35+/-0.3 liter/min, x) showed good correlation (r=0.95,
y=0.89x+0.11) and agreement (deltaCO(y-x)=0.03+/-0.08 [mean+/-SD] liter/min). In
the normal subjects, CO measured by ACMm agreed with CO by ACMa (r=0.90, p <
0.0001, deltaCO=-0.09+/-0.42 liter/min), PD (r=0.87, p < 0.0001, deltaCO=0.12+/
0.49 liter/min) and 2D (r=0.84, p < 0.0001, deltaCO=-0.16+/-0.48 liter/min). In
the patients, mitral regurgitant volume (MRV) by ACMm-ACMa agreed with PD-2D (r=
0.88, y=0.88x+6.6, p < 0.0001, deltaMRV=2.68+/-9.7 ml). CONCLUSIONS: We
determined that ACM is a feasible new method for quantifying LV outflow and
inflow volume to measure MRV and that ACM automatically performs calculations
that are equivalent to more time-consuming Doppler and 2D measurements.
Additionally, ACM should improve MR quantification in routine clinical practice.
PMID- 9768736
TI - Early age at repair prevents restrictive right ventricular (RV) physiology after
surgery for tetralogy of Fallot (TOF): diastolic RV function after TOF repair in
infancy.
AB - OBJECTIVES: To assess diastolic right ventricular (RV) physiology after tetralogy
of Fallot repair in infancy. BACKGROUND: Restrictive RV physiology after
tetralogy of Fallot repair is related to type of repair, pulmonary regurgitation,
and late arrhythmias. METHODS: Forty-seven patients were investigated, 27 and 20
patients in Lund and London, respectively. Median age at repair was 0.78 years
(0.08-0.99) and median follow-up was 3.0 years (0.08-10.4). Restrictive RV
physiology was assessed by Doppler echocardiography. RESULTS: Thirteen patients
(28%) had restrictive RV physiology at follow-up, three of 19 patients (16%) with
transatrial repair and 10 of 28 patients (32%) with transventricular repair,
respectively (p=0.1). Ten percent of the patients repaired before 6 months of age
were restrictive at follow-up, increasing to 38% with repair after 9 months.
Transannular patch (TAP) repair was performed in 55% of the patients, including
eight of 10 patients (80%) with repair before 6 months of age. Thirty-one percent
of the patients with TAP repair were restrictive. These restrictive patients had
more severe preoperative pulmonary stenosis (p < 0.05), were older at repair (p <
0.05), and had shorter duration of pulmonary regurgitation (p < 0.001) at follow
up. CONCLUSIONS: Restrictive RV physiology is inversely related to age at repair
and independent of type of outflow tract repair. Since TAP repair is more common
in early repair, and restriction seems to be less frequent, long-term follow-up
to assess adverse effects of pulmonary regurgitation is mandatory.
PMID- 9768737
TI - Effect of myocardial hypertrophy on systolic and diastolic function in children:
insights from the force-frequency and relaxation-frequency relationships.
AB - OBJECTIVE: The objective of this study was to evaluate the effect of myocardial
hypertrophy on systolic and diastolic properties of the left ventricle in
children. BACKGROUND: In children with myocardial hypertrophy, ejection phase
indices are invariably increased. However, indices of force-generation, e.g., end
systolic elastance and invasive indices of diastolic properties, have been
studied infrequently in children with myocardial hypertrophy. METHODS: We studied
10 children with congenital aortic stenosis or coarctation of aorta and nine
control patients. Systolic properties were assessed from shortening fraction, end
systolic fiber elastance (Ef(es)) measured at resting heart rates, and force
frequency relationship measured at heart rates increasing from 110 to 160 beats
per minute. Diastolic properties were assessed from time constant of relaxation
(tau) at matched heart rates, chamber stiffness constant, myocardial stiffness
constant, and relaxation-frequency relationship measured at gradually increasing
heart rates. RESULTS: Ef(es) remained unchanged by myocardial hypertrophy,
however, tau was prolonged (tauL: 27.3+/-2.3 vs. 21.8+/-2.2 ms, p < 0.001; and
tauD: 43.2+/-3.1 vs. 34.3+/-3.3 ms, p < 0.001). Both chamber and myocardial
stiffness constants remained unchanged. Incremental increases in heart rate
produced incremental improvement in both contraction and relaxation. Slopes of
force-frequency and relaxation-frequency relationships remained unchanged in the
experimental group. However, the relaxation-frequency relationship manifested a
parallel shift upward. CONCLUSIONS: In conscious, sedated children with
myocardial hypertrophy, systolic function assessed by an index of force
generation remains unchanged. However, relaxation is prolonged but passive
diastolic properties remain unaffected. The combined effect of hypertrophy and
heart rate does not alter the force-frequency and relaxation-frequency
relationships.
PMID- 9768738
TI - Evaluation of dynamic changes in microvascular flow during ischemia-reperfusion
by myocardial contrast echocardiography.
AB - BACKGROUND: Dynamic changes of myocardial blood flow have been observed after
reperfusion of an occluded coronary artery. MCE performed by intracoronary
contrast injection can provide an estimate of microvascular flow. We hypothesized
that MCE performed using intravenous infusion of a new generation contrast agent
and electrocardiogram-gated harmonic imaging would be able to assess serial
changes of microvascular perfusion. OBJECTIVE: To study the potential of
myocardial contrast echocardiography (MCE) to assess serial changes of
microvascular flow during ischemia-reperfusion. METHODS: Sixteen dogs underwent
90 or 180 min of left anterior descending coronary occlusion, followed by 180 min
of reperfusion. Regional blood flow (RBF) was measured with fluorescent
microspheres at baseline, during coronary occlusion, and at 5, 30, 90, and 180
min during reperfusion. At the same time points, MCE was performed with
intravenous infusion of AF0150 (4 mg/min). Gated end-systolic images in short
axis were acquired in harmonic mode and digitized on-line. Background-subtracted
videointensity measured from MCE and RBF obtained from fluorescent microspheres
were calculated for the risk area and for a control area, and were expressed as
the ratio of the two areas. RESULTS: After initial hyperemia, a progressive
reduction in flow was observed during reperfusion. MCE correctly detected the
time course of changes in flow during occlusion-reperfusion. Videointensity ratio
significantly correlated with RBF data (r=0.79; p < 0.0001). CONCLUSIONS: The
progressive reduction in blood flow occurring within the postischemic
microcirculation was accurately detected by MCE. This approach has potential
application in the evaluation and management of postischemic reperfusion in
humans.
PMID- 9768739
TI - In vivo effects of contrast media on coronary thrombolysis.
AB - OBJECTIVES: The aim of the present study was to evaluate the influence of
radiographic contrast media (CM) on alteplase-induced coronary thrombolysis.
BACKGROUND: Contrast media inhibit fibrinolysis in vitro and interact with
endothelial cells, platelets and the coagulation system. The in vivo effects of
CM on thrombolysis are not known. METHODS: Occlusive coronary artery thrombosis
was induced in 4 groups of 10 dogs by the copper coil technique. After 70 min of
occlusion the dogs were randomized to intracoronary injection of 2 ml kg(-1) of
either saline, a low-osmolar ionic CM (ioxaglate), a low-osmolar nonionic CM
(iohexol) or a high-osmolar ionic CM (amidotrizoate). Thrombolysis with alteplase
and co-therapy with aspirin and heparin was initiated after 90 min of occlusion.
The coronary artery flow was monitored with an electromagnetic flowmeter
throughout the experiment. RESULTS: Iohexol and amidotrizoate, but not ioxaglate,
were associated with longer reperfusion delays (time to optimal reperfusion: 67+/
48 min and 65+/-49 min, respectively, vs. 21+/-11 min after placebo; p < 0.05)
and shorter periods of coronary perfusion (optimal perfusion time: 21+/-26 min
and 21+/-28 min, respectively, vs. 58+/-40 min after placebo; p < 0.05). No
significant differences were observed between groups with regard to activated
partial thromboplastin times, circulating thrombin-antithrombin III complex
concentrations and fibrinogen. CONCLUSIONS: In this animal model administration
of iohexol and amidotrizoate before thrombolysis significantly delayed
reperfusion. This interaction should be considered in the design of clinical
trials of thrombolytic therapy that evaluate coronary artery patency and in
patients receiving local infusions of fibrinolytic agents.
PMID- 9768740
TI - Long-term endothelial dysfunction is more pronounced after stenting than after
balloon angioplasty in porcine coronary arteries.
AB - OBJECTIVE: To compare percutaneous transluminal coronary angioplasty (PTCA) and
stent implantation with respect to the long-term changes they induce in the newly
formed endothelium in porcine coronary arteries by studying both morphological
and functional parameters of the endothelium at 2 weeks and 3 months after
intervention. BACKGROUND: Problems affecting PTCA or stent implantation have been
overcome to a large extent by means of better techniques and the availability of
new drugs. Late problems, however, still exist in that restenosis affects a large
number of patients. With an increasing number of patients being treated with
stents, the problem of in-stent restenosis is of even greater concern, as this
seems difficult to treat. A functional endothelial lining is thought to be
important in controlling the growth of the underlying vascular tissue. We
hypothesized that the enhanced neointimal hyperplasia observed after stenting is
associated with a more pronounced and prolonged endothelial dysfunction. METHODS:
Arteries were analyzed using a dye-exclusion test and planimetry of permeable
areas. Thereafter, the arteries were processed for light and scanning electron
microscopy for assessment of morphology and proliferative response. RESULTS:
Leakage of the endothelium for molecules such as Evans blue-albumin as well as
prolonged endothelial proliferation is observed as late as 3 months after the
intervention, and is more pronounced after stenting. Permeability is associated
with distinct morphologic characteristics: endothelial retraction, the expression
of surface folds, and the adhesion of leukocytes. CONCLUSIONS: Stenting
especially decreases long-term vascular integrity with respect to permeability
and endothelial proliferation, and is associated with distinct morphologic
characteristics.
PMID- 9768742
TI - Aspirin and newer orally active antiplatelet agents in the treatment of the post
myocardial infarction patient.
AB - The thienopyridine derivatives, ticlopidine and clopidogrel, provide alternatives
to aspirin for use in the prevention of recurrent ischemic events in the post
myocardial infarction patient. These drugs act through a different mechanism than
aspirin and, as a result, have potentially different profiles of safety and
efficacy. The following discusses the clinical data collected supporting the use
of these drugs for secondary prevention and the unanswered questions that remain
regarding their use in subpopulations of individuals at risk. Based on the
available data, it may be concluded that aspirin should remain the drug of choice
for the prevention of recurrent ischemic events in the majority of patients who
have suffered a recent myocardial infarction.
PMID- 9768741
TI - Hypertrophic remodeling: gender differences in the early response to left
ventricular pressure overload.
AB - OBJECTIVES: To identify gender differences in left ventricular remodeling,
hypertrophy, and function in response to pressure overload due to ascending
aortic banding in rats. BACKGROUND: Gender may influence the adaptation to
pressure overload, as women with aortic stenosis have greater degrees of left
ventricular hypertrophy and better left ventricular function than men. METHODS:
Fifty-two weanling rats underwent ascending aortic banding (16 males, 18
females), or sham surgery (9 males, 9 females). At 6 and 20 weeks, rats underwent
transthoracic echo Doppler studies, and closed-chest left ventricular pressures
with direct left ventricular puncture. Perfusion-fixed tissues from eight rats
were examined morphometrically for myocyte cross-sectional area and percent
collagen volume. RESULTS: At 6 weeks after aortic banding, left ventricular
remodeling, extent of hypertrophy, and function appeared similar in male and
female rats. At 20 weeks, male but not female rats showed an early transition to
heart failure, with onset of cavity dilatation (left ventricular diameter=155%
vs. 121% of same-sex sham), loss of concentric remodeling (relative wall
thickness=102% vs. 139% of sham), elevated wall stress (systolic stress=266% vs.
154% of sham), and diastolic dysfunction (deceleration of rapid filling=251% vs.
190% of sham). Left ventricular systolic pressures were higher in female compared
with male rats (186+/-20 vs. 139+/-13 mm Hg), while diastolic pressures tended to
be lower (14+/-4 vs. 17+/-4 mm Hg). CONCLUSIONS: Gender significantly influences
the evolution of the early response to pressure overload, including the
transition to heart failure in rats with aortic stenosis.
PMID- 9768743
TI - President's Page: Practice expense: the struggle continues.
PMID- 9768744
TI - Concerning the Fontan patient's excessive minute ventilation during exercise.
PMID- 9768745
TI - Lipoprotein (a): an important risk factor in coronary artery disease.
PMID- 9768746
TI - Functional assessment of coronary stenoses.
PMID- 9768747
TI - Familial dilated cardiomyopathy.
PMID- 9768748
TI - Cytotoxic lymphocyte recognition of HLA-E: utilizing a nonclassical window to
peer into classical MHC.
PMID- 9768749
TI - The transcription factor NFAT4 is involved in the generation and survival of T
cells.
AB - Nuclear factor of activated T cells (NFAT) is a family of four related
transcription factors implicated in cytokine and early response gene expression
in activated lymphocytes. Here we report that NFAT4, in contrast to NFATp and
NFATc, is preferentially expressed in DP thymocytes. Mice lacking NFAT4 have
impaired development of CD4 and CD8 SP thymocytes and peripheral T cells as well
as hyperactivation of peripheral T cells. The thymic defect is characterized by
increased apoptosis of DP thymocytes. The increased apoptosis and hyperactivation
may reflect heightened sensitivity to TcR-mediated signaling. Further, mice
lacking NFAT4 have impaired production of Bcl-2 mRNA and protein. NFAT4 thus
plays an important role in the successful generation and survival of T cells.
PMID- 9768750
TI - Differential TCR signaling regulates apoptosis and immunopathology during antigen
responses in vivo.
AB - Clonal selection theories postulate that lymphocyte fate is regulated by antigen
receptor specificity. However, lymphocyte apoptosis is induced through nonantigen
specific receptors such as Fas (CD95/APO-1) or TNFR. We define a selective TCR
that controls apoptosis by Fas or TNFR stimulation. Variant ligands can deliver
this "competence to die" signal without the full TCR signals necessary for
cytokine synthesis. These partial agonists regulate T cell deletion in vivo even
when Fas or TNF is provided by T cells of unrelated specificity, but they do not
cause the liver necrosis that is associated with T cell elimination by the full
agonist. Thus, selective signaling ligands regulate T cell deletion and immune
damage in vivo and may be important for peripheral T cell tolerance.
PMID- 9768751
TI - IL-12 acts directly on DC to promote nuclear localization of NF-kappaB and primes
DC for IL-12 production.
AB - We analyzed the expression of an IL-12 receptor by fresh dendritic cells (DC) and
a DC line. Using RT-PCR, RNAse protection, and electrophoretic mobility shift
assay analysis, we found that DC possess an IL-12 receptor with beta1 subunit
(downstream box 1)-related differences from that on T cells. IL-12 signaling
through this receptor involved members of the NF-KB but not STAT family. The
unique properties of the IL-12 receptor on DC, characterized by a single class of
binding sites with a Kd of about 325 pM, may underlie rather unique effects, such
as IFNgamma-independent augmentation of class II antigen expression and priming
for LPS-induced production of IL-12.
PMID- 9768752
TI - A novel lysosome-associated membrane glycoprotein, DC-LAMP, induced upon DC
maturation, is transiently expressed in MHC class II compartment.
AB - We have identified a novel lysosome-associated membrane glycoprotein localized on
chromosome 3q26.3-q27, DC-LAMP, which is homologous to CD68. DC-LAMP mRNA is
present only in lymphoid organs and DC. A specific MAb detects the protein
exclusively in interdigitating dendritic cells. Expression of DC-LAMP increases
progressively during in vitro DC differentiation, but sharply upon activation
with LPS, TNFalpha, or CD40L. Confocal microscopy confirmed the lysosomal
distribution of the protein. Furthermore, DC-LAMP was found in the MHC class II
compartment immediately before the translocation of MHC class II molecules to the
cell surface, after which it concentrates into perinuclear lysosomes. This
suggests that DC-LAMP might change the lysosome function after the transfer of
peptide-MHC class II molecules to the surface of DC.
PMID- 9768753
TI - Kinetics of interaction of HLA-C ligands with natural killer cell inhibitory
receptors.
AB - The recognition of HLA-C molecules by specific inhibitory receptors is a crucial
step in the regulation of natural killer (NK) cell function. Using soluble,
recombinant HLA-C molecules and NK inhibitory receptors (NKIR, members of the
immunoglobulin superfamily), we show that HLA-C binds to NKIR molecules with
extremely fast association and dissociation rates, among the fastest of the
immune system interactions so far studied. These kinetics may be essential for
the biological function of NK cells, i.e., to facilitate the rapid
immunosurveillance of cells for absent or diminished expression of class I MHC
proteins.
PMID- 9768754
TI - Rapid death and regeneration of NKT cells in anti-CD3epsilon- or IL-12-treated
mice: a major role for bone marrow in NKT cell homeostasis.
AB - Natural killer T (NKT) cells express a T cell receptor (TCR) and markers common
to NK cells, including NK1.1. In vivo, NKT cells are triggered by anti-CD3epsilon
MAb to rapidly produce large amounts of IL-4 and by IL-12 to reject tumors. We
show here that anti-CD3epsilon MAb treatment rapidly depletes the liver (and
partially the spleen) of NKT cells and that homeostasis is achieved 1 to 2 days
later via NKT cell proliferation that occurs mainly in bone marrow. Similar
results were obtained in mice treated with IL-12. Collectively, our data
demonstrate that peripheral NKT cells are highly sensitive to activation-induced
cell death and that bone marrow plays a major role in restoring NKT cell
homeostasis.
PMID- 9768755
TI - Targeted disruption of the catalytic subunit of the DNA-PK gene in mice confers
severe combined immunodeficiency and radiosensitivity.
AB - The DNA-dependent protein kinase is a mammalian protein complex composed of Ku70,
Ku80, and DNA-PKcs subunits that has been implicated in DNA double-strand break
repair and V(D)J recombination. Here, by gene targeting, we have constructed a
mouse with a disruption in the kinase domain of DNA-PKcs, generating an animal
model completely devoid of DNA-PK activity. Our results demonstrate that DNA-PK
activity is required for coding but not for signal join formation in mice.
Although our DNA-PKcs defective mice closely resemble Scid mice, they differ by
having elevated numbers of CD4+CD8+ thymocytes. This suggests that the Scid mice
may not represent a null phenotype and may retain some residual DNA-PKcs
function.
PMID- 9768756
TI - A targeted DNA-PKcs-null mutation reveals DNA-PK-independent functions for KU in
V(D)J recombination.
AB - The DNA-dependent protein kinase (DNA-PK) consists of Ku70, Ku80, and a large
catalytic subunit, DNA-PKcs. Targeted inactivation of the Ku70 or Ku80 genes
results in elevated ionizing radiation (IR) sensitivity and inability to perform
both V(D)J coding-end and signal (RS)-end joining in cells, with severe growth
retardation plus immunodeficiency in mice. In contrast, we now demonstrate that
DNA-PKcs-null mice generated by gene-targeted mutation, while also severely
immunodeficient, exhibit no growth retardation. Furthermore, DNA-PKcs-null cells
are blocked for V(D)J coding-end joining, but retain normal RS-end joining.
Finally, while DNA-PK-null fibroblasts exhibited increased IR sensitivity, DNA
PKcs-deficient ES cells did not. We conclude that Ku70 and Ku80 may have
functions in V(D)J recombination and DNA repair that are independent of DNA-PKcs.
PMID- 9768757
TI - The structure of HLA-DM, the peptide exchange catalyst that loads antigen onto
class II MHC molecules during antigen presentation.
AB - The three-dimensional structure of the soluble ecto-domain of HLA-DM has been
determined to 2.5 A resolution by X-ray crystallography. HLA-DM has both peptide
exchange activity and acts as a chaperone to peptide-free class II MHC molecules.
As predicted, the structure is similar to that of classical class II MHC
molecules except that the peptide-binding site is altered to an almost fully
closed groove. An unusual cavity is found at the center of the region that binds
peptides in class II MHC molecules, and a tryptophanrich lateral surface is
identified that is a candidate both for binding to HLA-DR, to effect catalysis,
and to HLA-DO, an inhibitor.
PMID- 9768758
TI - Crystal structure of mouse H2-M.
AB - H2-M (HLA-DM in humans) resides in an acidic endosomal compartment, where it
facilitates the loading of antigenic peptides into the peptide-binding groove of
class II MHC. The crystal structure of a soluble form of H2-M has been solved to
3.1 A resolution, revealing a heterodimer with structural similarities to the MHC
family of proteins. In contrast to its antigen-presenting cousins, the membrane
distal alpha helices of H2-M pack closely together, occluding most of the binding
groove except for a single large pocket near the center. The structure of H2-M
has several unique features that may play a role in its function as a molecular
chaperone and peptide exchange factor.
PMID- 9768759
TI - EBV persistence in memory B cells in vivo.
AB - Epstein-Barr virus establishes latency in vitro by activating human B cells to
become proliferating blasts, but in vivo it is benign. In the peripheral blood,
the virus resides latently in resting B cells that we now show are restricted to
the sIgD memory subset. However, in tonsils the virus shows no such restriction.
We propose that EBV indiscriminately infects B cells in mucosal lymphoid tissue
and that these cells differentiate to become resting memory B cells that then
enter the circulation. Activation to the blastoid stage of latency is an
essential intermediate step in this process. Thus, EBV may persist by exploiting
the mechanisms that produce and maintain long-term B cell memory.
PMID- 9768760
TI - Epstein-Barr virus LMP2A drives B cell development and survival in the absence of
normal B cell receptor signals.
AB - Epstein-Barr virus (EBV) establishes a persistent latent infection in peripheral
B lymphocytes in humans and is associated with a variety of malignancies and
proliferative disorders. Latent membrane protein 2A (LMP2A) is one of only two
viral proteins expressed in latently infected B lymphocytes in vivo. LMP2A blocks
B cell receptor (BCR) signal transduction in vitro by binding the Syk and Lyn
protein tyrosine kinases. To analyze the significance of LMP2A expression in
vivo, transgenic mice with B cell lineage expression of LMP2A were generated.
LMP2A expression results in the bypass of normal B lymphocyte developmental
checkpoints allowing immunoglobulin-negative cells to colonize peripheral
lymphoid organs, indicating that LMP2A possesses a constitutive signaling
activity in nontransformed cells.
PMID- 9768761
TI - The pathway for processing leader-derived peptides that regulate the maturation
and expression of Qa-1b.
AB - Qa-1b and its human homolog, HLA-E, predominantly bind leader peptides derived
from other class I molecules. Their presentation is TAP-dependent and proteasome
independent. We demonstrate that Dd targeted to the cytosol does not generate the
Qa-1b peptide epitope even in the presence of lactacystin. Cells expressing
herpes virus ICP-47 block the generation of this epitope, demonstrating that TAP
functions in the transport of the peptide from cytosol to ER. This reveals a
pathway for antigen presentation of leader peptides that involves translocation
of a protein to the ER where its leader is cleaved followed by its release into
the cytosol and transport back into the ER. Further, it ensures that Qa-1b
expression mirrors the normal expression of class Ia molecules.
PMID- 9768762
TI - Impaired development of Th2 cells in IL-13-deficient mice.
AB - We report that Th2 cell cultures generated using T cells or splenocytes from IL
13-deficient mice produce significantly reduced levels of IL-4, IL-5, and IL-10
compared with wild-type. In contrast, IL-4 and IL-5 production by mast cells
stimulated in vitro with PMA, ionomycin, or IgE cross-linking are unaffected. In
vitro Th2 cell differentiation cannot be rescued by the addition of exogenous
factors, but in vivo antigen challenge and administration of IL-13 can increase
Th2-like cytokine responses as can infection with the parasitic nematode
Nippostrongylus brasiliensis. IL-13-deficient mice also have lower basal levels
of serum IgE and biased antigen-specific immunoglobulin responses. Thus, IL-13 is
an important regulator of Th2 commitment and may therefore play a central role in
atopy and infectious diseases.
PMID- 9768763
TI - Should induced hypertension be beneficial after traumatic brain injury?
PMID- 9768764
TI - Gastric fluid volume: is it really a risk factor for pulmonary aspiration?
PMID- 9768765
TI - Gastric contents in children presenting for upper endoscopy.
AB - Previous studies of gastric contents in children presenting for surgery
specifically excluded those with gastrointestinal disorders. Because these
children often need sedation or anesthesia for procedures such as upper
endoscopy, it is important to determine the gastric fluid volume and pH in this
group to better characterize their risk of aspiration. We therefore analyzed the
gastric fluid volume and pH of children with a variety of gastrointestinal
symptoms presenting for upper endoscopy. After obtaining institutional review
board approval, the stomach contents of 248 children (aged 2 mo to 18 yr)
presenting for upper endoscopy were prospectively measured under direct
endoscopic vision. Children were fasted for both solids and liquids for at least
6 h (<6 mo) or 8 h (>6 mo). Gastric fluid pH was measured using pH paper.
Children received either deep sedation or general anesthesia and were grouped
according to their presenting diagnosis. Results were analyzed by using analysis
of variance, Kruskal-Wallis, and correlation (P value < 0.05). The mean gastric
fluid volume was 0.35 +/- 0.45 mL/kg (range 0-3.14 mL/kg), and the mean gastric
fluid pH was 1.37 +/- 1.6 (range 1-7). Of the children, 33% had gastric fluid
volumes >0.4 mL/kg, 87% had gastric fluid pH <2.5, and 30% had gastric fluid
volume >0.4 mL/kg and pH <2.5. Children with the presenting complaint of
abdominal pain had the largest gastric fluid volumes. These data are not
appreciably different from historical controls (healthy children fasted for an
equivalent period of time who did not have gastrointestinal symptoms).
IMPLICATIONS: When fasted for at least 6-8 h, children with a history of
gastrointestinal symptoms presenting for upper endoscopy did not have gastric
contents with increased volume and acidity compared with previously published
groups of children without gastric symptoms who were fasted the same length of
time. These results do not support the argument that children with
gastrointestinal symptoms pose an increased anesthetic risk for aspiration.
PMID- 9768766
TI - A granisetron-droperidol combination prevents postoperative vomiting in children.
AB - This study was performed to compare the efficacy of a granisetron-droperidol
combination with each antiemetic alone to prevent postoperative vomiting after
tonsillectomy with or without adenoidectomy in children. One hundred eighty
pediatric patients, ASA physical status I, aged 4-10 yr, were enrolled in a
prospective, randomized, double-blind investigation and assigned to one of three
treatment regimens: granisetron 40 microg/kg (Group G), droperidol 50 microg/kg
(Group D), or granisetron 40 microg/kg plus droperidol 50 microg/kg (Group GD) (n
= 60 in each group). These drugs were administered i.v. after an inhaled
induction. The same standard general anesthetic technique and postoperative
analgesia were used throughout. The rate of complete response, defined as no
emesis and no need for rescue antiemetic, 0-3 h after anesthesia was 83% in Group
G, 60% in Group D, and 97% in Group GD (P = 0.029 versus Group G, P = 0.001
versus Group D). The corresponding rates 3-24 h after anesthesia were 83%, 55%,
and 97% (P = 0.029 versus Group G, P = 0.001 versus Group D). No clinically
important adverse events were observed in any of the groups. In conclusion, a
granisetron-droperidol combination is superior to each antiemetic alone in
complete response in children undergoing general anesthesia for tonsillectomy.
IMPLICATIONS: We compared the efficacy of granisetron plus droperidol with each
antiemetic alone for the prevention of postoperative vomiting in children. The
granisetron-droperidol combination was highly effective against postoperative
emesis.
PMID- 9768767
TI - A comparison of three modes of ventilation with the use of an adult circle system
in an infant lung model.
AB - We examined the efficiency of an adult circle system with adult bellows to
deliver minute ventilation (VE) to an infant test lung model. A Narkomed 2B
system (North American Drager, Telford, PA) using three modes of ventilator setup
were used: A = time-cycled, volume-controlled using bellows excursion to control
delivered volume; B = time-cycled, pressure-controlled using inspiratory pressure
limit adjustment to control delivered volume; C = time-cycled, pressure
controlled using the inspiratory flow adjustment to control delivered volume. VE
was measured with two compliances (normal and low) and four endotracheal tube
(ETT) sizes (2.5-, 3.0-, 3.5-, and 4.0-mm inner diameter). VE was measured at
peak inspiratory pressures (PIP) of 20, 30, 40 or 50 cm H2O while respiratory
rate (RR) was held constant at 20 breaths/min. VE was measured as RR was set at
20, 30, 40, or 50 breaths/min while target PIP was held constant at 20 cm H2O.
Data were analyzed using the multiple regression technique. With the low
compliance model, VE was nearly identical regardless of the ventilator setup.
With the normal compliance model, minor differences in VE were observed,
especially at the highest RR and PIP. VE was dependent on RR, PIP, and lung
compliance. Overall, the ventilator setup resulted in minor changes in VE. Very
high PIPs were required to deliver VE to the low compliance model. ETT size did
not affect VE when lung compliance was low; however, smaller ETT size was a
factor when test lung compliance was normal, decreasing delivered VE at higher
PIP and RR. We conclude that with a Narkomed 2B adult circle system VE is
dependent on PIP, RR, and lung compliance, but not on mode of ventilator setup.
IMPLICATIONS: The results of this laboratory investigation indicate that when an
adult circle system is used during infant anesthesia, the ventilation delivered
depends primarily on the respiratory rate, peak inspiratory pressure, and the
compliance of the lung being ventilated, rather than on the specific mode of
ventilator setup.
PMID- 9768768
TI - Decreased mivacurium requirements and delayed neuromuscular recovery during
sevoflurane anesthesia in children and adults.
AB - The purpose of this study was to compare the mivacurium infusion requirements and
neuromuscular recovery in adults and children during propofol/opioid and
sevoflurane anesthesia. Seventy-five adult and 75 pediatric patients were
randomized to receive propofol/opioid 0.5 or 1.0 minimum alveolar anesthetic
concentration (MAC) (age-related) sevoflurane anesthesia. Plasma cholinesterase
(PChE) activity was measured. Neuromuscular blockade was monitored by train-of
four (TOF) stimulation every 10 s and adductor pollicis electromyography. A bolus
of 2 x the 95% effective dose of mivacurium (0.25 mg/kg) was followed by an
infusion titrated to maintain 90%-95% blockade. Mivacurium doses were recorded
every 5 min. At the end of surgery, the infusion was stopped, and recovery from
mivacurium was monitored until TOF > or =0.7. PChE concentrations were within the
normal range (adults 4-12 KU/L, children 6-16 KU/L) and correlated with
mivacurium dose. Mivacurium infusion rates were higher in children than in
adults: at 30 min, the rates in children were 13.1 +/- 6.4, 8.1 +/- 4.7, and 5.2
+/- 2.9 microg x kg(-1) x min(-1) at 0, 0.5, and 1.0 MAC sevoflurane,
respectively; the corresponding rates in adults were 5.9 +/- 3.1, 4.3 +/- 1.7,
and 2.9 +/- 0.7 microg x kg(-1) x min(-1) (P < 0.01). Sevoflurane decreased
mivacurium requirements, maximal decreases at 45 min in children and 10 min in
adults, and delayed neuromuscular function recovery. Children recovered twice as
quickly as adults, achieving TOF > or =0.7 at 9.8 +/- 2.5, 11.4 +/- 2.8, and 19.6
+/- 6.3 min compared with 19.9 +/- 5.4, 26.4 +/- 8.3, and 32.9 +/- 9.8 min in
adults (P < 0.0001). In conclusion, mivacurium requirements were correlated with
PChE, were greater in children than in adults, and were reduced by sevoflurane.
Neuromuscular recovery occurred more rapidly in children and was delayed by
sevoflurane. IMPLICATIONS: The mivacurium infusion requirement to maintain
constant 90%-95% neuromuscular block during anesthesia is correlated with plasma
cholinesterase activity. It is increased in children and reduced by the inhaled
anesthetic sevoflurane. Despite the larger dose administered to children,
recovery from block occurred more rapidly in children than in adults and was
delayed by sevoflurane.
PMID- 9768769
TI - Anaphylactoid reaction due to the administration of ondansetron in a pediatric
neurosurgical patient.
PMID- 9768770
TI - Protamine reversal of heparin affects platelet aggregation and activated clotting
time after cardiopulmonary bypass.
AB - Bleeding after cardiopulmonary bypass (CPB) is related to multiple factors.
Excess protamine weakens clot structure and decreases platelet function;
therefore, an increased activated clotting time (ACT) after protamine reversal of
heparin may be misinterpreted as residual heparin anticoagulation. We evaluated
the effects of protamine, recombinant platelet factor 4 (rPF4), and
hexadimethrine on ACT in blood obtained after CPB. In addition, we examined the
effect of protamine on in vitro platelet aggregation. Incremental doses of
protamine, rPF4, and hexadimethrine were added to heparinized blood from CPB, and
ACTs were performed. Incremental concentrations of protamine were added to
heparinized platelet-rich plasma, and aggregometry was induced by adenosine
diphosphate (ADP) and collagen. The mean heparin concentration at the end of CPB
was 3.3 U/mL. Protamine to heparin ratios >1.3:1 produced a significant
prolongation of the ACT that was not seen with rPF4 and was observed only with
5:1 hexadimethrine to heparin ratios. ADP-induced platelet aggregation was
reduced with protamine administration > or =1.3:1. Excessive protamine reversal
of heparin prolongs ACT and alters ADP-induced platelet aggregation in a dose
dependent manner in vitro. Additional protamine administered to treat a prolonged
ACT may further increase clotting time, reduce platelet aggregation, and
potentially contribute to excess bleeding after CPB. IMPLICATIONS: We found that
excess protamine prolonged the activated clotting time and altered platelet
function after cardiopulmonary bypass, whereas heparin antagonists, such as
recombinant platelet factor 4 and hexadimethrine, exhibited a wider therapeutic
range without adversely affecting the activated clotting time. Approaches to
avoid excess protamine or use of alternative heparin antagonists after
cardiopulmonary bypass may be beneficial.
PMID- 9768771
TI - Uncompensated blood loss is not tolerated during acute normovolemic hemodilution
in anesthetized pigs.
AB - Clinically, hemodilution to a hematocrit of 9% has been studied, but the effects
of hypovolemia during this degree of hemodilution have not been elucidated. We
studied the response to blood loss during extreme hemodilution and evaluated
indicators of hypovolemia. Systemic and myocardial hemodynamics, oxygen
transport, and blood lactate concentrations were measured in 12 anesthetized pigs
exposed to a graded blood loss of 10, 20, 30, and 40 mL/kg. Six animals were
hemodiluted (hematocrit 10.8% +/- 1.4%, mean +/- SD), and six animals served as
controls (hematocrit 34.6% +/- 1.5%). Hemodilution decreased systemic oxygen
delivery to 9.5 +/- 0.6 mL x kg(-1) x min(-1) (controls 21.7 +/- 3.9 mL x kg(-1)
x min(-1)) (P < 0.01) despite a 31% increase in cardiac output. Systemic oxygen
uptake was unchanged. Arterial lactate increased to 3.3 +/- 1.1 mM/L (controls
1.6 +/- 0.6 mM/L) (P < 0.05), and mixed venous oxygen saturation (SvO2) decreased
to 38.2% + 4.8% (controls 68.6% +/- 2.9%) (P < 0.01). At a blood loss of 10
mL/kg, cardiac output continued to be greater in the hemodiluted animals (P <
0.01). Arterial blood pressure decreased to 61 +/- 8 mmHg (controls 84 +/- 18 mm
Hg) (P < 0.05), whereas heart rate was unchanged. Systemic oxygen delivery
decreased to 8.8 +/- 1.2 mL x kg(-1) x min(-1) (controls 14.1 +/- 2.5 mL x kg(-1)
x min(-1)) (P < 0.01). Systemic oxygen uptake was maintained by a further
increase in oxygen extraction, and SvO2 decreased to 29.7% +/- 7.3%, compared
with 55.3% +/- 9.0% in controls (P < 0.01). Arterial lactate increased to 4.9 +/-
1.4 mM/L (controls 1.8 +/- 0.8 mM/L) (P < 0.01). Myocardial oxygen delivery and
lactate uptake were unchanged. When the blood loss equaled 30 mL/kg, myocardial
lactate production occurred, and two hemodiluted animals died of circulatory
failure. Central venous and capillary wedge pressures changed minimally during
the blood loss and did not differ between groups. We conclude that a decrease in
arterial blood pressure and SvO2 were early signs of hypovolemia during
hemodilution, whereas central venous pressure and pulmonary capillary wedge
pressure were insensitive indicators. IMPLICATIONS: Anesthetized pigs with
extremely low hemoglobin levels (one third of normal) showed poor tolerance to
blood loss >10 mL/kg. A decreasing arterial blood pressure, a decreasing oxygen
saturation in the venous blood, and an increase in arterial blood lactate
concentration were useful indicators of blood loss.
PMID- 9768772
TI - Dexamethasone decreases the incidence of shivering after cardiac surgery: a
randomized, double-blind, placebo-controlled study.
AB - Shivering after cardiac surgery is common, and may be a result of intraoperative
hypothermia. Another possible etiology is fever and chills secondary to
activation of the inflammatory response and release of cytokines by
cardiopulmonary bypass. Dexamethasone decreases the gradient between core and
skin temperature and modifies the inflammatory response. The goal of this study
was to determine whether dexamethasone can reduce the incidence of shivering. Two
hundred thirty-six patients scheduled for elective coronary and/or valvular
surgery were randomly assigned to receive either dexamethasone 0.6 mg/kg or
placebo after the induction of anesthesia. All patients received standard
monitoring and anesthetic management. After arrival in the intensive care unit
(ICU), nurses unaware of the treatment groups recorded visible shivering, as well
as skin and pulmonary artery temperatures. Analysis of shivering rates was
performed by using chi2 tests and logistic regression analysis. Compared with
placebo, dexamethasone decreased the incidence of shivering (33.0% vs 13.1%; P =
0.001). It was an independent predictor of reduced incidence of shivering and was
also associated with a higher skin temperature on ICU admission and a lower
central temperature in the early postoperative period. IMPLICATIONS:
Dexamethasone is effective in decreasing the incidence of shivering. The
effectiveness of dexamethasone is independent of temperature and duration of
cardiopulmonary bypass. Shivering after cardiac surgery may be part of the
febrile response that occurs after release of cytokines during cardiopulmonary
bypass.
PMID- 9768773
TI - Desflurane and isoflurane produce similar alterations in systemic and pulmonary
hemodynamics and arterial oxygenation in patients undergoing one-lung ventilation
during thoracotomy.
AB - We tested the hypothesis that desflurane (DES) and isoflurane (ISO) produce
similar effects on systemic and pulmonary hemodynamics and arterial oxygenation
before, during, and after one-lung ventilation (OLV) in patients undergoing
thoracotomy. After obtaining informed consent, anesthesia was induced with sodium
thiopental or thiamylal, fentanyl, and vecuronium in 61 ASA physical status II-IV
patients. Patients were randomly assigned to receive either DES (n = 30) or ISO
(n = 31) in 100% O2 in separate groups. Hemodynamic data (radial and pulmonary
artery [PA] catheters) were recorded, and blood gas values were obtained before
and after induction; at selected intervals before, during, and after OLV; and
before emergence. DES significantly (P < 0.05) increased heart rate (HR) and
decreased mean arterial pressure (MAP) and cardiac output (CO). PA pressures and
pulmonary vascular resistance (PVR) increased; systemic vascular resistance (SVR)
was unchanged. Increases in HR and CO and decreases in MAP and SVR occurred
during OLV and DES. Reductions in PaO2 (411 +/- 88 to 271 +/- 131 mm Hg 5 min
after beginning OLV; mean +/- SD) and content (CaO2) and increases in shunt
fraction (Qs/Qt; 0.25 +/- 0.12 to 0.40 +/- 0.19 at 5 min after beginning OLV)
were also observed. ISO increased HR and PA pressures but did not alter MAP, CO,
and PVR, in contrast to the findings with DES. Reductions in MAP and SVR and
increases in CO and PA pressures were observed during OLV in the presence of ISO.
Similar to the findings during DES, decreases in PaO2 and CaO2 and increases in
Qs/Qt occurred during OLV and ISO. We conclude that DES and ISO produce very
similar alterations in systemic and pulmonary hemodynamics and arterial
oxygenation in patients undergoing OLV during thoracotomy. IMPLICATIONS:
Desflurane and isoflurane produce similar cardiovascular and pulmonary effects
before, during, and after one-lung ventilation in patients undergoing lung
surgery.
PMID- 9768774
TI - The effect of magnesium sulphate on hemodynamics and its efficacy in attenuating
the response to endotracheal intubation in patients with coronary artery disease.
AB - Laryngoscopy and endotracheal intubation may produce adverse hemodynamic effects.
Magnesium has direct vasodilating properties on coronary arteries and inhibits
catecholamine release, thus attenuating the hemodynamic effects during
endotracheal intubation. We studied 36 patients with coronary artery disease
(CAD) scheduled for elective coronary artery bypass grafting to evaluate the
hemodynamic effects of magnesium and its efficacy in attenuating the response to
endotracheal intubation. Patients received either 0.1 mL/kg (50%) magnesium
sulfate (50 mg/kg) (Group A, n = 19) or isotonic sodium chloride solution (Group
B, n = 17) before the induction of anesthesia and 0.05 mL/kg of isotonic sodium
chloride solution (Group A) or lidocaine 2% (1 mg/kg) (Group B) before
intubation. The hemodynamic variables were recorded before induction, after the
trial drug, after induction, and after endotracheal intubation. Automatic ST
segment analysis was performed throughout the study period. Magnesium sulfate
administration was associated with increased cardiac index (P < 0.01), a minimal
increase in heart rate, and a significant decrease in mean arterial pressure
(MAP) and systemic vascular resistance (SVR) (P < 0.001). None of the patients in
the magnesium group had significant ST depression compared with three patients in
the control group. The magnesium group patients had a significantly lesser
increase in MAP (P < 0.05) and SVR (P < 0.01) compared with the control group
patients who received lidocaine before endotracheal intubation. Thus, magnesium
is an useful adjuvant to attenuate endotracheal intubation response in patients
with CAD. IMPLICATIONS: Endotracheal intubation produces adverse hemodynamic
effects, which may be more detrimental in patients with coronary artery disease
than in healthy patients. The present study shows that magnesium administered
before endotracheal intubation can attenuate this response better than lidocaine.
PMID- 9768775
TI - Pulmonary hypertension and major surgery.
PMID- 9768776
TI - Factors affecting discharge time in adult outpatients.
AB - Discharge time (total recovery time) is one determinant of the overall cost of
outpatient surgery. We performed this study to determine what factors affect
discharge time. Details regarding patients, anesthesia, surgery, and recovery
were recorded prospectively for 1088 adult patients undergoing ambulatory surgery
over an 8-mo period. The contribution of factors to variability in the discharge
time was assessed by using multivariate linear regression analysis. In the last 4
mo of the study, nurses indicated the causes of discharge delays > or =50 min in
Phase 1 or > or =70 min in Phase 2 recovery. When all anesthetic techniques were
included, anesthetic technique was the most important determinant of discharge
time (R2 = 0.10-0.15; P = 0.001), followed by the Phase 2 nurse. After general
anesthesia, the Phase 2 nurse was the most important factor (R2 = 0.13; P = 0.01
0.001). In women, the choice of general anesthetic drugs was significant (R2 =
0.04; P = 0.002). The three most common medical causes of delay were pain,
drowsiness, and nausea/vomiting. System factors were the foremost cause of Phase
2 delays (41%), with lack of immediate availability of an escort accounting for
53% of system-related delays. We conclude that efforts to shorten discharge time
would best be directed at improving nursing efficiency; ensuring availability of
an escort for the patient; and preventing postoperative pain, drowsiness, and
emetic symptoms. The selection of anesthetic technique and anesthetic drug seems
to be of selective importance in determining discharge time depending on patient
gender and type of surgery. IMPLICATIONS: The relative importance of anesthetic
and nonanesthetic factors were evaluated as determinants of discharge time after
ambulatory surgery. Postoperative nursing care was the single most important
factor after general anesthesia; anesthetic drugs, anesthetic technique, and
prevention of pain and emetic symptoms were of selective importance depending on
patient gender and type of surgery.
PMID- 9768777
TI - A total intravenous anesthetic technique for outpatient facial laser resurfacing.
PMID- 9768778
TI - A survey on the intended purposes and perceived utility of preoperative
cardiology consultations.
AB - Cardiology consultations are often requested by surgeons and anesthesiologists
for patients with cardiovascular disease. There can be confusion, however,
regarding both the reasons for a consultation and their effect on patient
management. This study was designed to determine the attitudes of physicians
toward preoperative cardiology consultations and to assess the effect of such
consultations on perioperative management. A multiple-choice survey regarding the
purposes and utility of cardiology consultations was sent to randomly selected
New York metropolitan area anesthesiologists, surgeons, and cardiologists. In
addition, the charts of 55 consecutive patients aged >50 yr who received
preoperative cardiology consultations were examined to determine the stated
purpose of the consult, recommendations made, and concordance by surgeons and
anesthesiologists with cardiologists' recommendations. Of the 400 surveys sent to
each specialty, 192 were returned from anesthesiologists, 113 were returned from
surgeons, and 129 were returned from cardiologists. There was substantial
disagreement on the importance and purposes of a cardiology consult:
intraoperative monitoring, "clearing the patient for surgery," and advising as to
the safest type of anesthesia were regarded as important by most cardiologists
and surgeons but as unimportant by anesthesiologists (all P < 0.05). Most
surgeons (80.2%) felt obligated to follow a cardiologist's recommendations,
whereas few anesthesiologists (16.6%) felt so obligated (P < 0.05). The most
commonly stated purpose of the 55 cardiology consultations examined was
"preoperative evaluation." Only 5 of these (9%) were obtained for patients in
whom there was a new finding. Of the cardiology consultations, 40% contained no
recommendations other than "proceed with case," "cleared for surgery," or
"continue current medications." Recommendations regarding intraoperative
monitoring or cardiac medications were largely ignored. IMPLICATIONS: We conclude
that there seems to be considerable disagreement among anesthesiologists,
cardiologists, and surgeons as to the purposes and utility of cardiology
consultations. A review of 55 consecutive cardiology consultations suggests that
most of them give little advice that truly affects management.
PMID- 9768779
TI - Long-term pharmaceutical cost reduction using a data management system.
AB - Cost containment is an important issue in medicine today, and the ability to
control costs and maintain quality patient care presents a challenge to
practitioners. Educating practitioners about drug costs has been identified as an
effective method, but the benefits of education are usually short-lived. To
evaluate the role of education in cost control, pharmaceutical use and
performance improvement data were analyzed at a tertiary care institution during
two time periods. A total of 4,530 anesthesia records and associated performance
improvement data from March to June 1993 were analyzed as a baseline. These data
were shared with the clinicians of an anesthesia department and used to educate
practitioners regarding the costs and use of injectable pharmaceuticals and to
identify areas in which cost savings could be achieved. The same information from
10,600 cases during January to October 1996 were compared with the early group.
The expenditures for injectable pharmaceuticals to provide anesthesia were
decreased by more than $30,000 per month, or $32 per case, without changing the
performance indicators that were monitored, and has been maintained for >3 yr.
IMPLICATIONS: By using a data management system, the cost for medications to
provide anesthesia has been reduced without changing the quality of patient care.
PMID- 9768780
TI - Reliability of the transient hyperemic response test in detecting changes in
cerebral autoregulation induced by the graded variations in end-tidal carbon
dioxide.
AB - The transient hyperemic response (THR) in the middle cerebral artery (MCA) after
the release of brief compression of the ipsilateral common carotid artery has
been used to study cerebral autoregulation. We conducted the present study to
evaluate the reliability of THR to detect changes in cerebral autoregulation
induced by graded variations in PETCO2. Seven healthy adult volunteers were
recruited. Fifteen THR tests were performed on every volunteer: three at baseline
PETCO2, three each at PETCO2 of 7.5 mm Hg and 15 mm Hg above the baseline, and
then three each at PETCO2 of 7.5 mm Hg and 15 mm Hg below the baseline. Transient
hyperemic response ratio (THRR) and strength of autoregulation (SA) were
calculated using established formulae. Both THRR and SA were highly sensitive
(96%) in detecting the changes in cerebral autoregulation induced by graded
changes in PETCO2. The within-individual variability of SA was significantly
smaller than that of THRR at all levels of PETCO2. IMPLICATIONS: This study
demonstrates the reliability of the THR test, when used for repetitive
measurements, in detecting changes in cerebral autoregulation induced by graded
changes in PETCO2. This test may provide a simple and noninvasive method of
evaluating changes in cerebral autoregulation within an individual.
PMID- 9768781
TI - The effect of hyperventilation and hyperoxia on cerebral venous oxygen saturation
in patients with traumatic brain injury.
AB - Eighteen head-injured patients undergoing hyperventilation were studied for
changes in jugular venous oxygen saturation (SjvO2) and arteriovenous oxygen
content difference (AVDO2) in response to changes in PaO2 and PaCO2. SjvO2
decreased significantly from 66% +/- 3% to 56% +/- 3% (mean +/- SD) when PaCO2
decreased from 30 to 25 mm Hg at a PaO2 of 100-150 mm Hg. SjvO2 values returned
to baseline (66% +/- 2%) when PaCO2 was restored to 30 mm Hg. Repetition of the
study at a PaO2 of 200-250 mm Hg produced a similar pattern. However, SjvO2
values were significantly greater with PaO2 within the range of 200-250 mm Hg
(77% +/- 4% and 64% +/- 3%) than SjvO2 measured at a PaO2 of 100-150 mm Hg at
PaCO2 values of both 30 and 25 mm Hg. AVDO2 also improved with a PaO2 of 200-250
mm Hg at each PaCO2 (P < 0.001). In conclusion, decreases in SjvO2 associated
with decreases in PaCO2 may be offset by increasing PaO2. IMPLICATIONS: The
adequacy of cerebral oxygenation can be estimated in head-injured patients by
monitoring jugular bulb oxygen saturation and the arteriovenous oxygenation
content difference. Increasing the partial pressure of arterial oxygen above
normal offset deleterious effects of hyperventilation on jugular bulb oxygen
saturation and arteriovenous oxygenation content difference in head-injured
patients.
PMID- 9768782
TI - The effects of sevoflurane on cerebral blood flow autoregulation in rats.
AB - In this study, we investigated the effect of sevoflurane on cerebral blood flow
(CBF) autoregulation in rats. Twenty-four male Sprague-Dawley rats were randomly
assigned to receive one of the following anesthetic treatments. In Group 1 (n =
8, control) anesthesia was maintained using fentanyl (25 microg x kg(-1) x h(-1))
and N2O/O2 (fraction of inspired oxygen 0.33). In Group 2 (n = 8) and Group 3 (n
= 8), anesthesia was maintained using 2% sevoflurane (1 minimum alveolar
anesthetic concentration [MAC]) and 2 MAC sevoflurane (4 vol%) in O2/air
(fraction of inspired oxygen 0.33), respectively. Cortical CBF autoregulation was
measured during graded hemorrhage within the mean arterial pressure (MAP) range
of 100-30 mm Hg using laser Doppler flowmetry. CBF was constant with fentanyl/
N2O (Group 1) and 1 MAC sevoflurane (Group 2) within the MAP range of 100-40 mm
Hg. In Group 3 (2 MAC sevoflurane), CBF decreased as a linear function of
hemorrhagic hypotension. These results indicate that CBF autoregulation was
intact during 1 MAC sevoflurane. In contrast, CBF autoregulation was impaired
with 2 MAC sevoflurane. This is probably related to a reduction of baseline
cerebrovascular tone with higher concentrations of sevoflurane, which results in
a decreased capacity of autoregulatory cerebrovascular dilation during
hemorrhage. IMPLICATIONS: The purpose of the present study was to investigate the
effect of sevoflurane on cerebral blood flow autoregulation in rats. Cerebral
blood flow autoregulation was intact with 1 minimum alveolar anesthetic
concentration sevoflurane but was impaired with 2 minimum alveolar anesthetic
concentration sevoflurane.
PMID- 9768783
TI - Increased plasma concentration of adrenomedullin in patients with subarachnoid
hemorrhage.
AB - Adrenomedullin (AM) is a potent hypotensive peptide originally identified in
pheochromocytoma tissues. Impaired cardiovascular conditions, such as
hypertension, myocardial infarction, and septic shock, stimulate production of
AM. This study was performed to determine whether subarachnoid hemorrhage (SAH)
altered plasma AM concentration. Plasma concentrations of AM in 17 patients with
SAH were measured for 2 wk after the onset of SAH by AM-specific
radioimmunoassay. Plasma concentrations of AM were increased in patients with SAH
throughout the study period, compared with those in control subjects. Plasma
concentrations of AM in patients classified as Hunt and Kosnik grade III or IV
were significantly higher than those classified as Hunt and Kosnik grade I or II
on the day of and the day after the onset of SAH. However, plasma concentrations
of AM were unaffected by angiographic vasospasm. These findings suggest that
plasma concentrations of AM are increased in patients with SAH and may reflect
the severity of SAH. IMPLICATIONS: Adrenomedullin has been reported to affect the
cerebral circulation. This study was performed to determine whether subarachnoid
hemorrhage, a typical cerebrovascular disorder, altered plasma adrenomedullin
concentrations. We found that plasma adrenomedullin concentrations increased in
patients with subarachnoid hemorrhage, although no relationship was found between
plasma adrenomedullin concentration and angiographic vasospasm. Plasma
adrenomedullin concentration may reflect the severity of hemorrhage.
PMID- 9768785
TI - Infraclavicular brachial plexus block: parasagittal anatomy important to the
coracoid technique.
AB - Infraclavicular brachial plexus block is a technique well suited to prolonged
continuous catheter use. We used a coracoid approach to this block to create an
easily understood technique. We reviewed the magnetic resonance images of the
brachial plexus from 20 male and 20 female patients. Using scout films, the
parasagittal section 2 cm medial to the coracoid process was identified. Along
this oblique section, we located a point approximately 2 cm caudad to the
coracoid process on the skin of the anterior chest wall. From this point, we
determined simulated needle direction to contact the neurovascular bundle and
measured depth. At the skin entry site, the direct posterior insertion of a
needle will make contact with the cords of the brachial plexus where they
surround the second part of the axillary artery in all images. The mean (range)
distance (depth along the needle shaft) from the skin to the anterior wall of the
axillary artery was 4.24 +/- 1.49 cm (2.25-7.75 cm) in men and 4.01 +/- 1.29 cm
(2.25-6.5 cm) in women. Hopefully, this study will facilitate the use of this
block. IMPLICATIONS: We sought a consistent, palpable landmark for facilitation
of the infraclavicular brachial plexus block. We used magnetic resonance images
of the brachial plexus to determine the depth and needle orientation needed to
contact the brachial plexus. Hopefully, this study will facilitate the use of
this block.
PMID- 9768784
TI - The tocolytic effect of catecholamines in the gravid rat uterus.
AB - Maternal catecholamines increase dramatically in labor because of pain and
emotional stress. Because the uterus is richly endowed with both alpha- and beta
adrenergic receptors, catecholamines could alter uterine activity. We assessed
the effect of clinically encountered concentrations of these catecholamines on
uterine activity and modeled the effect of the abrupt reduction in circulating
epinephrine that occurs during effective labor analgesia. Term pregnant rat uteri
were excised, and cross-sectional rings were mounted for isometric force
recording. Log concentration-response curves for epinephrine, norepinephrine, and
their combination on uterine activity were constructed from 10(-12) to 10(-6) M.
Catecholamine responses were repeated in the presence of phentolamine, an alpha
adrenergic blocker or propranolol, a beta-adrenergic blocker. The abilities of
oxytocin and of washout of catecholamines to reverse catecholamine-induced
changes in uterine activity were also assessed. Epinephrine caused dose-dependent
reductions in uterine activity, blocked by propranolol. Epinephrine
concentrations in the clinical range(10(-9) to 10(-8) M; 100-1000 pg/mL)
decreased uterine activity to 49.6% +/- 6.6% (mean +/- SE) of control.
Norepinephrine caused a dose-dependent increase in uterine activity, which was
blocked by phentolamine. In the clinical range (10(-8) M), uterine activity was
139.2% +/- 13.40% of control. The combination of both catecholamines, however,
was nearly as tocolytic as epinephrine alone. Oxytocin antagonized catecholamine
induced tocolysis, and washout of epinephrine or both catecholamines increased
uterine activity. We conclude that mixed catecholamines are significantly
tocolytic at concentrations encountered in laboring women. In this in vitro
model, reduction in epinephrine concentration, comparable to that which occurs
during effective analgesia, significantly increases uterine activity.
IMPLICATIONS: Maternal catecholamines increase in labor, but epinephrine
decreases dramatically after regional analgesia. In this study, we found that
norepinephrine and epinephrine together decrease uterine contractile activity and
that decreased epinephrine causes significantly increased uterine activity.
PMID- 9768786
TI - Spinal anesthesia increases pulmonary responsiveness to methacholine in guinea
pigs.
AB - It has been postulated that regional anesthesia, when feasible, is the best
anesthetic approach in asthmatic patients. However, there are reports of severe
bronchospasm during regional anesthesia. In the present study, we developed an
experimental model of spinal (subarachnoid) anesthesia in guinea pigs and studied
respiratory system responsiveness to aerosolized methacholine. The animals
received sodium pentobarbital (50 mg/kg intraperitoneally), a tracheotomy, and
mechanical ventilation. Four groups of animals were studied: guinea pigs that
received spinal anesthesia with lidocaine (500 microL of 2% solution) (n = 7);
guinea pigs that received spinal administration of isotonic sodium chloride
solution (500 microL) (n = 7); guinea pigs that received an intraperitoneal
injection of lidocaine (500 microL of 2% solution) (n = 6); and control guinea
pigs (n = 7). The concentration of methacholine chloride that resulted in 50% of
the maximal value of respiratory system elastance was lower in guinea pigs that
received spinal anesthesia compared with the other three groups (P < 0.005 for
control group, P < 0.01 for spinal saline group, and P < 0.05 for intraperitoneal
lidocaine group). Our results suggest that spinal anesthesia results in an
increase in pulmonary responsiveness to bronchoconstrictive stimuli.
IMPLICATIONS: Regional anesthesia has been considered the best anesthetic
approach in asthmatic patients, although there are reports of severe
bronchospasm. We developed an experimental model of spinal anesthesia with
lidocaine in guinea pigs and studied respiratory responsiveness to methacholine,
a bronchoactive agonist. Spinal anesthesia resulted in an increase in respiratory
responsiveness.
PMID- 9768788
TI - Fundamental properties of local anesthetics: half-maximal blocking concentrations
for tonic block of Na+ and K+ channels in peripheral nerve.
AB - Local anesthetics suppress excitability by interfering with ion channel function.
Ensheathment of peripheral nerve fibers, however, impedes diffusion of drugs to
the ion channels and may influence the evaluation of local anesthetic potencies.
Investigating ion channels in excised membrane patches avoids these diffusion
barriers. We investigated the effect of local anesthetics with voltage-dependent
Na+ and K+ channels in enzymatically dissociated sciatic nerve fibers of Xenopus
laevis using the patch clamp method. The outside-out configuration was chosen to
apply drugs to the external face of the membrane. Local anesthetics reversibly
blocked the transient Na+ inward current, as well as the steady-state K+ outward
current. Half-maximal tonic inhibiting concentrations (IC50), as obtained from
concentration-effect curves for Na+ current block were: tetracaine 0.7 microM,
etidocaine 18 microM, bupivacaine 27 microM, procaine 60 microM, mepivacaine 149
microM, and lidocaine 204 microM. The values for voltage-dependent K+ current
block were: bupivacaine 92 microM, etidocaine 176 microM, tetracaine 946 microM,
lidocaine 1118 microM, mepivacaine 2305 microM, and procaine 6302 microM.
Correlation of potencies with octanol:buffer partition coefficients (logP0)
revealed that ester-bound local anesthetics were more potent in blocking Na+
channels than amide drugs. Within these groups, lipophilicity governed local
anesthetic potency. We conclude that local anesthetic action on peripheral nerve
ion channels is mediated via lipophilic drug-channel interactions. IMPLICATIONS:
Half-maximal blocking concentrations of commonly used local anesthetics for Na+
and K+ channel block were determined on small membrane patches of peripheral
nerve fibers. Because drugs can directly diffuse to the ion channel in this
model, these data result from direct interactions of the drugs with ion channels.
PMID- 9768787
TI - The advantages of the lateral decubitus position after spinal anesthesia with
hyperbaric tetracaine.
AB - We investigated the effects of lateral decubitus positioning after spinal
anesthesia with hyperbaric tetracaine on the spread of sensory blockade and
hemodynamic variables. One hundred ASA physical status I or II patients scheduled
for elective surgery to the lower limb received spinal anesthesia at a rate of
approximately 0.1 mL/s using 0.5% tetracaine in 7.5% glucose with 0.125%
phenylephrine in the lateral decubitus position with the operated side dependent.
They were randomly divided into three groups: patients in Group I were placed
supine immediately after spinal injection; those in Group II remained in the
lateral position for 10 min before being turned supine; those in Group III were
kept in the lateral position for 20 min then turned supine. Neural block was
assessed by cold, pinprick, and touch sensation, and a modified Bromage scale.
Hemodynamic variables included blood pressure, heart rate, and the use of
ephedrine for the treatment of hypotension. The median (10th, 90th percentiles)
peak dermatomal level to pinprick on the dependent side in Group III was T8 (T11,
T5), which was significantly lower than that in Groups I and II, which extended
to T4 (T9, T3) and T5 (T10, T2), respectively (P < 0.05). The difference in the
maximal cephalad spread of sensory blockade between both sides in Group III was
only one dermatome but was statistically significant (P < 0.05); in contrast,
there was no significant difference in the maximal sensory level between both
sides in Groups I and II. The use of ephedrine for the treatment of hypotension
was significantly less frequent in Group III than the other groups. We conclude
that keeping a patient in the lateral decubitus position for 20 min after
hyperbaric tetracaine spinal anesthesia maintains preferential anesthetic
distribution to the dependent side. Despite small differences between the two
sides, the restricted spread of blockade and less hemodynamic variability may be
clinically advantageous. IMPLICATIONS: The effects of posture on the spread of
hyperbaric spinal anesthesia have not been adequately investigated. The results
of the present study suggest an advantage of prolonged lateral decubitus
positioning after intrathecal hyperbaric tetracaine.
PMID- 9768789
TI - Postoperative analgesic effects of three demand-dose sizes of fentanyl
administered by patient-controlled analgesia.
AB - Many studies have demonstrated the postoperative analgesic efficacy of fentanyl
delivered i.v. by patient-controlled analgesia (PCA) devices at demand doses
ranging from 10 to 50 microg, but none has sought to define the optimal fentanyl
PCA dose. In this randomized, double-blind, multicenter study, we compared the
safety and efficacy of three administered demand-dose sizes of fentanyl (20, 40,
and 60 microg) in 150 patients after major surgery. Efficacy was dose-dependent;
positive response rates (i.e., a global assessment score of "very good" or
"excellent" and the absence of severe opioid adverse effects) were 42%, 52%, and
68% for the 20, 40, and 60 microg demand-dose groups, respectively, and were
significantly higher in the 60 microg demand-dose group. The number of doses
administered and missed attempts were significantly smaller in the 40 and 60
microg demand-dose groups compared with the 20 microg demand-dose group. This
suggests that the 20 microg demand dose provided inadequate pain relief. Adverse
respiratory events were more frequent and mean respiratory rates were
significantly slower with the 60 microg demand dose, compared with the 20 or 40
microg demand doses. These results indicate that, of these three doses, the 40
microg demand dose was optimal for fentanyl PCA management of moderate to severe
pain after major surgery. IMPLICATIONS: The postoperative analgesic efficacy of
fentanyl delivered i.v. by patient-controlled analgesia devices has been
demonstrated for demand doses ranging from 10 to 50 microg, but the optimal
fentanyl dose remains unknown. In this randomized, double-blind study, we
compared three demand dose sizes of fentanyl (20, 40, and 60 microg) and found
that the 40 microg demand dose was the most appropriate for fentanyl patient
controlled analgesia management of postoperative pain.
PMID- 9768790
TI - Cryoanalgesia: effect on postherniorrhaphy pain.
AB - Cryoanalgesia versus sham treatment was applied to the ilioinguinal and
iliohypogastric nerves after mesh repair of an inguinal hernia under local
anesthesia in 48 male patients in a prospective, randomized, and observer- and
patient-blinded trial. Pain was scored daily during rest, while coughing, and
during mobilization to the sitting position for 1 wk and weekly for 8 wk on a
four-point verbal rank scale. Use of supplementary analgesics and sensory
disturbances were recorded. Assessments were made for allodynia, hyperalgesia,
and mechanical pain detection thresholds 8 wk postoperatively. Cumulative pain
scores for the first postoperative week were equal in the two groups, as was the
use of analgesics. Eight weeks postoperatively, three cases of hyperalgesia to
pinprick were detected in the cryoanalgesia group, and 10 patients in the
cryoanalgesia group versus 5 in the sham-treatment group reported disturbed
sensibility. We conclude that cryoanalgesia of the iliohypogastrical and
ilioinguinal nerve does not decrease postherniorrhaphy pain. IMPLICATIONS: Does
freezing of sensory nerves in the groin reduce pain after hernia repair? Extreme
cold (-60 degrees C) was applied in a double-blind, randomized study. No
difference in pain scores was found. Sensory disturbances were seen in treatment
and control patients. Freezing cannot be recommended for pain relief after hernia
repair.
PMID- 9768791
TI - Posttreatment with propofol terminates lidocaine-induced epileptiform
electroencephalogram activity in rabbits: effects on cerebrospinal fluid
dynamics.
AB - There are no controlled studies to determine whether propofol given after the
onset of lidocaine-induced seizures (posttreatment) stops lidocaine-induced
seizures. In this study, we determined whether posttreatment with propofol
abolishes lidocaine-induced epileptiform electroencephalogram (EEG) activity as
effectively as does midazolam, and cerebrospinal fluid (CSF) dynamics during
lidocaine-induced epileptiform EEG activity and its treatment. EEG activity and
CSF dynamics were determined in two groups of anesthetized rabbits at each of
four experimental conditions: baseline, lidocaine-induced epileptiform activity,
treatment with midazolam (n = 6) or propofol (n = 6), and return to baseline. The
analog EEG signal was converted into a set of digital parameters using aperiodic
analysis, and CSF dynamics were determined using ventriculocistemal perfusion.
Propofol (3.8 +/- 1.3 mg/kg) stopped epileptiform activity, as did midazolam (2.0
+/- 1.7 mg/kg). The rates of CSF formation or reabsorption and resistances to CSF
reabsorption or flow at the arachnoid villi did not differ among conditions or
between groups. Our results indicate that propofol and midazolam both terminate
epileptiform activity without changing CSF dynamics. IMPLICATIONS: Propofol may
be an alternative to benzodiazepines for treating lidocaine-induced epileptiform
electroencephalogram activity in patients.
PMID- 9768792
TI - Comparison of patient-controlled epidural analgesia with and without background
infusion after gastrectomy.
AB - To assess the analgesic efficacy and side effects of concurrent infusion in
patient-controlled epidural analgesia (PCEA) after upper abdominal surgery, 40
patients undergoing elective gastrectomy under general anesthesia were allocated
to two groups in this randomized, double-blind study: one received a 2.5-mL
incremental bolus in a solution of 0.2% bupivacaine and 10 microg/mL fentanyl,
and the other received the same bolus dose plus a 2.5-mL/h infusion of the same
solution. The number of demands was smaller (P < 0.001) in the PCEA plus infusion
group than in the PCEA alone group during the 48-h postoperative period. The
average hourly fentanyl and bupivacaine doses were larger (P < 0.0001) in the
PCEA plus infusion group than in the PCEA alone group. Visual analog scale pain
scores on coughing in the PCEA plus infusion group were lower than in the PCEA
alone group (P < 0.05). There was a greater incidence of pruritus in the PCEA
plus infusion group (P < 0.05), but no serious side effects were observed in
either group. In conclusion, a background infusion in PCEA with a mixture of
fentanyl and bupivacaine decreases the incidence of postoperative pain and
reduces the degree of pain associated with coughing without serious side effects
after gastrectomy. IMPLICATIONS: A background infusion in patient-controlled
epidural analgesia with a mixture of fentanyl and bupivacaine decreased the
incidence of postoperative pain and reduced the degree of the pain associated
with coughing without serious side effects in this randomized, double-blind study
after gastrectomy.
PMID- 9768793
TI - Percutaneous electrical nerve stimulation: an alternative to antiviral drugs for
acute herpes zoster.
PMID- 9768794
TI - Jet ventilation in upper airway obstruction: description and model lung testing
of a new jetting device.
AB - Patients with critical upper airway stenosis require a tracheotomy for corrective
surgery. We describe a new transtracheal device that permits safe ventilation of
these patients without tracheotomy. It is based on a coaxial bicannular design
that allows "push-pull" ventilation by jetting gas through the inner cannula and
applying suction through the outer cannula. It further allows monitoring of
airway pressure, tidal volume, and end-tidal CO2. The device was placed in the
"trachea" of an artificial lung, and the preparation was made airtight by sealing
the proximal end of the trachea. Tidal volumes and their associated pressures
were measured simultaneously at different parts of the airway at several lung
compliances and airway resistance settings while varying the jet and suction
pressures. A large range of tidal volumes was achieved at safe airway pressures
using clinically relevant airway resistance and lung compliance settings. Airway
pressures measured through the device correlated well with pressures measured
directly in the airways at the same time. Tidal volumes, measured through a
Wright respirometer in the suction line, exceeded actual values at high suction
settings and decreased below actual values at low suction settings. This new form
of jet ventilation allowed efficient ventilation of the artificial lung with a
totally occluded upper airway. IMPLICATIONS: Tracheotomy is required for surgery
to relieve stridor because gas forced into the trachea at high pressures through
a percutaneously placed needle (jetting) cannot be exhaled quickly enough for
respiration. We describe a device that allows jetting in the stridorous patient
by actively assisting expiration, thereby eliminating the tracheotomy
requirement.
PMID- 9768795
TI - A comparison of the disposable versus the reusable laryngeal mask airway in
paralyzed adult patients.
AB - A disposable (polyvinyl chloride) laryngeal mask airway (LMA) with dimensions
identical to, but physical properties different from (stiffer tube/thicker cuff),
the reusable (silicone) LMA has recently become available. We performed a
randomized, cross-over study of 60 paralyzed, anesthetized patients to test the
hypothesis that the use of these devices was different in terms of ease of
insertion, airway sealing pressure, fiberoptic position, and changes in intracuff
pressure during N2O anesthesia. We also tested the hypothesis that the airway
sealing pressure of the LMA is suboptimal if the cuff is inflated to a high
intracuff pressure. Both the devices were inserted into each patient in random
order, and their performance was assessed at two intracuff pressures (60 and 180
cm H2O) by a blind observer. Subsequently, intracuff pressures were measured
during N2O anesthesia for the second device. Ease of insertion was similar: there
was no difference in first attempt success rates (97% vs 98%) and insertion times
(15 vs 13 s) for the disposable and reusable LMA, respectively. There were no
differences in airway sealing pressure or fiberoptic position. Airway sealing
pressure was significantly higher at 60 cm H2O intracuff pressure compared with
the airway sealing pressure at 180 cm H2O for both devices (P < 0.02). During N2O
anesthesia, the intracuff pressure remained stable for the disposable LMA but
increased significantly for the reusable LMA. We conclude that the disposable and
reusable LMAs perform similarly in paralyzed adult patients, but that the
disposable LMA has more stable intracuff pressures during N2O anesthesia.
Inflation of the LMA to high intracuff pressures produces a suboptimal seal.
IMPLICATIONS: This randomized, single-blind, within-patient study of 60 adult
patients shows that the disposable (polyvinyl chloride) and reusable (silicone)
laryngeal mask airways perform similarly, but that the disposable laryngeal mask
airway has more stable intracuff pressures during N2O anesthesia. Inflation of
either device to high intracuff pressures produces a suboptimal seal.
PMID- 9768796
TI - The effects of the lateral position on cardiopulmonary function during
laparoscopic urological surgery.
AB - Laparoscopic urological surgery is usually performed transperitoneally with
retroperitoneal insufflation of carbon dioxide (CO2) in the lateral position. We
studied whether a difference in the side of lateral position affected hemodynamic
and pulmonary functions during pneumoperitoneum. Fifteen patients (eight in the
right and seven in the left lateral position) undergoing elective laparoscopic
urological surgery were studied under general anesthesia. Hemodynamic variables
and blood gas data were recorded. Before insufflation, mean arterial pressure
(MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP),
and pulmonary capillary wedge pressure (PCWP) in the right lateral position were
higher than those in the left lateral position. Pneumoperitoneum increased MAP,
MPAP, CVP, PCWP, and cardiac index but decreased systemic vascular resistance in
the right lateral position. Similar changes occurred during pneumoperitoneum in
the left lateral position, but the changes were less than those in the right
lateral position. The respiratory index (PaO2/PAO2), intrapulmonary shunt, and
SpO2 did not change during pneumoperitoneum in either lateral position. Changing
the side of the lateral position affected hemodynamic function but did not affect
pulmonary oxygenation during pneumoperitoneum. IMPLICATIONS: The right and left
lateral positions produced different hemodynamic changes during laparoscopic
urological surgery. The increases in preload and cardiac index and the decrease
in systemic vascular resistance were greater in the right than in the left
lateral position. Respiratory changes were not affected differently between the
right and left lateral positions.
PMID- 9768797
TI - Single-dose tropisetron for preventing postoperative nausea and vomiting after
breast surgery.
AB - In this randomized, double-blind, placebo-controlled study, we compared the
efficacy of tropisetron 5 mg with tropisetron 2 mg for the prevention of
postoperative nausea and vomiting (PONV) after breast surgery. One hundred forty
eight female patients were randomized to receive either tropisetron 5 mg (n =
49), tropisetron 2 mg (n = 49), or saline (n = 50) before the induction of
anesthesia with thiopental and morphine. Anesthesia was maintained with nitrous
oxide and isoflurane. Postoperative analgesia was provided by patient-controlled
analgesia with i.v. morphine. The incidence of PONV, the pain score, and the
analgesic requirement were recorded for 48 h. There was no difference among
groups in patient characteristics, risk factors for PONV, morphine consumption,
or side effects. During the first 6 h postoperatively, the incidence of PONV
after tropisetron 2 mg and 5 mg were similar and were superior to placebo (P <
0.001). After 6 h, the incidence of PONV increased significantly in patients who
had received tropisetron 2 mg (P = 0.01) and was greater than that in patients
who had received tropisetron 5 mg (P = 0.001). We conclude that single-dose
tropisetron 5 mg is more effective than tropisetron 2 mg in the prevention of
PONV after breast surgery. IMPLICATIONS: Breast surgery is associated with a high
incidence of postoperative nausea and vomiting. A single dose of i.v. tropisetron
5 mg is well tolerated and decreases the number of vomiting and nausea episodes
after surgery.
PMID- 9768798
TI - Neuromuscular effects of rocuronium during sevoflurane, isoflurane, and
intravenous anesthesia.
AB - The potency and time course of action of rocuronium were studied in patients
anesthetized with 66% nitrous oxide in oxygen and 1.5 minimum alveolar anesthetic
concentration of sevoflurane or isoflurane, or a propofol infusion. Potency was
estimated by using the single-bolus technique. Neuromuscular block was measured
by stimulation of the ulnar nerve and by recording the force of contraction of
the adductor pollicis muscle. The mean (95% confidence limits) of the 50% and 95%
effective doses were estimated tobe 142 (129-157) and 265 (233-301) microg/ kg,
165 (146-187) and 324 (265-396) microg/kg, and 183 (163-207) and 398 (316-502)
microg/kg during sevoflurane, isoflurane, and propofol anesthesia, respectively
(P < 0.05 for sevoflurane versus propofol). The mean +/- SD times to onset of
maximal block after rocuronium 0.6 mg/kg were 0.96 +/- 0.16, 0.90 +/- 0.16, and
1.02 +/- 0.15 min during sevoflurane, isoflurane, and propofol anesthesia,
respectively. The respective times to recovery of the first response in the train
of-four (TOF) stimulation (T1) to 25% and 90% were 45 +/- 13.1 and 83 +/- 29.3
min, 35 +/- 6.1 and 56 +/- 15.9 min, and 35 +/- 9.2 and 55 +/- 19.4 min. The
times to recovery of the TOF ratio to 0.8 were 103 +/- 30.7, 69 +/- 20.4, and 62
+/- 21.1 min, and the 25%-75% recovery indices were 26 +/- 11.7, 12 +/- 5.0, and
14 +/- 6.9 min, respectively. There were no differences among groups in the times
for onset of action or to recovery of T1 to 25%. However, the times for recovery
of T1 to 90%, TOF ratio to 0.8, and recovery index in the sevoflurane group were
all significantly longer compared with the other two groups (P < 0.05, < 0.01,
and < 0.01, respectively). We conclude that the effects of rocuronium, especially
duration of action, are significantly enhanced during sevoflurane compared with
isoflurane and propofol anesthesia. IMPLICATIONS: In routine clinical use, the
effects of rocuronium are enhanced by sevoflurane, in comparison with isoflurane
and propofol anesthesia, and the recovery is slower. Particular attention should
be paid to monitoring of neuromuscular block during sevoflurane anesthesia.
PMID- 9768799
TI - The analgesic potency of dexmedetomidine is enhanced after nerve injury: a
possible role for peripheral alpha2-adrenoceptors.
AB - This study investigated the analgesic potency and site of action of systemic
dexmedetomidine, a selective alpha2-adrenoceptor (alpha2AR) agonist, in normal
and neuropathic rats. Ligation of the L5-6 spinal nerves produced a chronic
mechanical and thermal neuropathic hyperalgesia in rats. von Frey fibers and a
thermoelectric Peltier device were used to measure mechanical and heat withdrawal
thresholds over the hindpaw. Systemic dexmedetomidine dose-dependently increased
the mechanical and thermal thresholds in the control animals (50% effective dose
[ED50] 144 and 180 microg/kg intraperitoneally [i.p.], respectively). Neuropathic
animals responded to much smaller doses of dexmedetomidine with mechanical and
thermal ED50 values of 52 and 29 microg/kg i.p., respectively. There was no
difference between the control and neuropathic animals with respect to
dexmedetomidine-evoked sedation, as determined by decreased grid crossings in an
open-field activity chamber (ED50 12 and 9 microg/kg i.p., respectively).
Atipamezole, a selective alpha2AR antagonist, blocked the analgesic and sedative
actions of dexmedetomidine inboth the neuropathic and control animals. However, L
659,066, a peripherally restricted alpha2AR antagonist, could only block the
analgesic actions of dexmedetomidine in the neuropathic rats, with no effect in
control animals. In conclusion, nerve injury enhanced the analgesic but not the
sedative potency of systemic dexmedetomidine and may have shifted the site of
alpha2 analgesic action to outside the blood-brain barrier. IMPLICATIONS: We
tested the analgesic efficacy of the alpha2 agonist dexmedetomidine in normal and
nerve-injured rats. The analgesic potency of dexmedetomidine was enhanced after
nerve injury with a site of action outside the central nervous system.
Peripherally restricted alpha2 agonists may be useful in the management of
neuropathic pain.
PMID- 9768800
TI - The effect of the interaction of propofol and alfentanil on recall, loss of
consciousness, and the Bispectral Index.
AB - The Bispectral Index (BIS) correlates well with the level of consciousness with
single anesthetic drugs. We studied the effect of the interaction of propofol
with alfentanil on propofol concentration and BIS associated with 50% probability
of loss of consciousness and lack of recall (Cp50 and BIS50, respectively). We
studied 40 consenting volunteers at two institutions who were randomly assigned
to receive stepped increases of propofol (10 subjects at each site), propofol
plus alfentanil 50 ng/mL (10 subjects at Emory site), or propofol plus alfentanil
100 ng/mL (10 subjects at Duke site) by using a target-controlled infusion
device. Measures of sedation, BIS, deltaBIS (absolute change of BIS after a
painful stimulus), memory, and drug concentration were obtained at each target
drug concentration. The relation among BIS, measured drug concentration, sedation
score, and presence or absence of recall was determined by linear and logistic
regression for different drug regimens, and the prediction probability (Pk) was
calculated. The addition of alfentanil in increasing doses did not significantly
affect the BIS50 and propofol Cp50 values for loss of consciousness and lack of
recall. DeltaBIS was significantly decreased by both an increase in the
concentration of propofol and the presence of alfentanil. The Pk for BIS was
>0.93 with all drug regimens, better than those of the target and measured
propofol concentrations. We conclude that BIS correlated well with the hypnotic
component of anesthesia independent of the presence of an opioid. Moreover, the
level of consciousness, and, therefore, the BIS index, is affected by a painful
stimulus, and this response is ablated either by opioids or increasing propofol
concentration. IMPLICATIONS: In volunteers, the sedation and changes in memory
function produced by propofol correlated well with changes in the Bispectral
Index. This relationship was not altered by the addition of an analgesic
(alfentanil). However, in moderately sedated patients who received a painful
stimulus, the Bispectral Index increased, but this response was blocked by the
analgesic or increasing propofol concentrations.
PMID- 9768801
TI - Pulmonary vasodilation by ketamine is mediated in part by L-type calcium
channels.
AB - We studied the effects of ketamine in the isolated rat lung under conditions of
increased pulmonary arterial pressure using the thromboxane A2 mimic, U46619, and
in response to ventilatory hypoxia. Ketamine caused dose-dependent vasodilation,
and possible mechanisms were evaluated using verapamil, meclofenamate, N(omega)-L
nitro-L-arginine benzyl ester (an inhibitor of nitric oxide synthase), and U
38883A (an ATP-sensitive potassium channel antagonist) in the isolated blood
perfused rat lung. Under increased tone conditions, N(omega)-L-nitro-L-arginine
benzyl ester, meclofenamate, and U-38883A had no significant effect in
attenuating ketamine-induced vasodilator responses. In a final series of
experiments, verapamil significantly attenuated ketamine-induced vasodilator
responses. These data suggest that ketamine has significant vasodilator activity
in the pulmonary vascular bed of the rat, which seems to be mediated by an L-type
calcium channel-sensitive pathway. These responses are not mediated or modulated
by the release of nitric oxide, the activation of K+ ATP channels, or the release
of vasodilator cyclooxygenase products. IMPLICATIONS: In this study, we examined
the mechanism of the vasodilator effects of ketamine in the blood-perfused rat
lung. The results of the present study suggest that ketamine-induced vasodilator
responses are mediated by an L-type calcium channel-sensitive pathway.
PMID- 9768802
TI - Rat strain minimally influences anesthetic and convulsant requirements of inhaled
compounds in rats.
AB - We assessed the effect of rat strain on susceptibility to anesthesia and
convulsions produced by inhaled compounds. We determined the minimum alveolar
anesthetic concentration (MAC) of desflurane and nitrous oxide, and the
convulsive 50% effective dose (ED50) of 1,2-dichlorohexafluorocyclobutane,
flurothyl, and difluoromethyl-1-chlorotetrafluoroethyl ether in five strains
(three inbred [Long Evans, Sprague-Dawley, and Wistar] and two outbred [Fischer
and Brown Norway]). Strain had slight effects on anesthetic potency, the strains
with the highest MAC values (Long Evans and Brown Norway) having values < or =28%
greater than the strains with the lowest values (Sprague Dawley and Wistar). MAC
for nitrous oxide correlated directly with MAC for desflurane as a function of
strain. MAC for either desflurane or nitrous oxide correlated inversely with the
convulsive ED50 of 1,2-dichlorohexafluorocyclobutane, but correlated poorly (and
directly) with the convulsive ED50 of the remaining compounds. Convulsivity
varied little as a function of strain (greatest difference 21%) and did not vary
consistently as a function of strain. No consistent difference was seen between
inbred versus outbred strains. IMPLICATIONS: Rat strain has a minimal effect on
the potency of inhaled anesthetics or the convulsant activity of inhaled
compounds. It seems that the sites acted on by inhaled compounds to produce
anesthesia and convulsions are conserved across common rat strains.
PMID- 9768803
TI - The interaction of eltanolone and fentanyl with special reference to logistic
regression analysis.
AB - We investigated whether fentanyl decreases the serum concentrations of the
steroid anesthetic eltanolone effective in producing loss of consciousness in 50%
of patients (EC50induction) and in preventing movement at skin incision in 50% of
patients (EC50incision). For anesthetic induction, patients received effect-site
target concentrations of fentanyl 0.0, 1.5, 3.0, or 4.5 ng/mL and eltanolone 500,
750, 1000, or 1200 ng/mL. Loss of response to verbal command was assessed after
10 min. For incision, patients received effect-site target concentrations of
fentanyl 0.5,1.5, 3.0, or 4.5 ng/mL and eltanolone 547-2926 ng/mL. Movement at
incision was assessed at least 10 min after new targets were entered. Probability
of loss of consciousness and of movement versus arterial serum concentration
combinations were analyzed by logistic regression. Dixon up-down analysis was
used to estimate ET50incision effective target concentration combinations. In the
absence of fentanyl, anesthesia was induced in only 1 of 12 patients, which
suggests that the EC50induction is >1500 ng/mL at fentanyl 0.0 ng/mL. With
fentanyl (38 patients), eltanolone EC50induction was independent of fentanyl
concentration, calculated as 628 ng/mL. For the incision phase (52 patients),
logistic regression failed to generate a valid model. Dixon analysis (43
patients) produced an eltanolone ET50incision of 2288 ng/mL at fentanyl targets
of 0.5 ng/mL, 754 ng/mL at 1.5 ng/mL, 735 ng/mL at 3.0 ng/mL, and 645 ng/mL at
4.5 ng/mL. Fentanyl reduced the serum concentration of eltanolone required to
produce loss of consciousness and the target concentration of eltanolone required
to prevent movement to skin incision. IMPLICATIONS: Fentanyl reduced the serum
concentration of eltanolone required to produce loss of consciousness and the
target concentration of eltanolone required to prevent movement to skin incision.
Future interaction studies of this nature using logistic regression should model
responses to hypnotic alone separately from responses to hypnotic-analgesic
combinations.
PMID- 9768804
TI - Is Helicobacter pylori infection an occupational hazard for anesthesiologists?
PMID- 9768805
TI - Reversibility of parkinsonism-induced acute upper airway obstruction by
benztropine therapy.
PMID- 9768806
TI - Nonsteroidal antiinflammatory drugs during lactation.
PMID- 9768807
TI - Use of the laryngeal mask airway as an alternative to the tracheal tube during
ambulatory anesthesia.
PMID- 9768808
TI - Complications of CO2 flooding the surgical field in open heart surgery: an old
technique revisited.
PMID- 9768809
TI - Use of a lighted stylet for tracheal intubation through the intubating laryngeal
mask.
PMID- 9768810
TI - "Damping" of an arterial line: an unlikely cause.
PMID- 9768811
TI - Relief of chronic refractory hiccups with glossopharyngeal nerve block.
PMID- 9768812
TI - Transient global amnesia: a cause for postanesthetic memory disorder.
PMID- 9768813
TI - Torsade de pointes ventricular tachycardia during, but not necessarily caused by,
sevoflurane anesthesia.
PMID- 9768814
TI - Sevoflurane and torsade de pointes.
PMID- 9768815
TI - A simple oxygen delivery system for the transportation of intubated patients.
PMID- 9768816
TI - Asystole under hypotensive epidural anesthesia.
PMID- 9768817
TI - Chemistry of dexrazoxane and analogues.
AB - The bisdioxopiperazine dexrazoxane (DEX; ICRF-187) has proven to be clinically
effective in reducing the cardiotoxicity of doxorubicin and the toxicity of other
anthracyclines. Doxorubicin and the other anthracyclines are thought to exert
their toxicity through iron-based oxygen free radical-induced oxidative stress on
the relatively unprotected cardiac muscle. On hydrolysis, DEX forms a compound
(ADR-925) similar in structure to EDTA, which, like EDTA, is a strong chelator of
iron and other metal ions. Dexrazoxane presumably exerts its cardioprotective
effects by either binding free or loosely bound iron, or iron complexed to
doxorubicin, thus preventing or reducing site-specific oxygen radical production
that damages cellular components. The hydrolysis-activation of DEX to ADR-925 can
occur through either enzymatic or nonenzymatic routes. Iron(III)-anthracycline
complexes are directly able to promote ring-opening hydrolysis of DEX. Both
ferrous and ferric ions (as well as several other divalent metal ions) can
promote the hydrolysis of the one-ring open intermediates of DEX to ADR-925,
which suggests that these intermediates may be pharmacologically active.
Paradoxically, the ferric complex of ADR-925 has been shown to be capable of
being reductively activated to mediate hydroxyl radical formation. This
observation suggests that DEX may be acting through its ability to prevent site
specific oxygen radical damage by iron-anthracycline complexes.
PMID- 9768818
TI - The role of iron in doxorubicin-induced cardiomyopathy.
AB - Doxorubicin participates in a wide range of free radical reactions. The drug can
undergo one electron reduction to the corresponding semiquinone, leading the
generation of superoxide and hydrogen peroxide. Additionally, the drug causes the
disappearance of cardiac glutathione peroxidase, leaving the heart with no means
of disposing of the hydrogen peroxide thus generated. Doxorubicin also is a
powerful iron chelator and the resultant iron-drug complex is an efficient
catalyst of the conversion of hydrogen peroxide to the highly reactive hydroxyl
radical. Without the drug-iron complex, little or no cardiac production of
hydroxyl radical occurs and heart damage does not occur.
PMID- 9768819
TI - Preclinical animal models of cardiac protection from anthracycline-induced
cardiotoxicity.
AB - The chronic cardiotoxic effects of anthracyclines were initially detected in
clinical trials with daunorubicin and doxorubicin. The clinical importance of
anthracycline-induced chronic cardiotoxicity has led to the development of
several animal models of this syndrome. Animal species examined in detail as
models of this cardiac toxicity include the rabbit, the normotensive and
spontaneously hypertensive rat, the mouse, the pig, and the dog. The advantages
and disadvantages of these animal models differ according to species: small
animals can be used for comparative investigations of anthracycline analogues
and/or protectors, which may be available only in limited amounts, while large
animals can be used for studies in which evaluation of cardiac function are to be
made. Among the various animals examined, the spontaneously hypertensive rat and
the beagle dog are considered the most suitable small and large animal models,
respectively, because of the reproducibility of the lesions induced by
anthracyclines in the two species. A variety of pharmacologic agents has been
tested for cardioprotective activity. The most successful of these agents are
those that function as antioxidants, because they either scavenge reactive oxygen
species or prevent their formation. The most clinically useful of these agents is
ICRF-187 (dexrazoxane), which has been found to be cardioprotective in all animal
models.
PMID- 9768820
TI - Preclinical models of cardiac protection and testing for effects of dexrazoxane
on doxorubicin antitumor effects.
AB - The ability of dexrazoxane (DEX) to protect against doxorubicin (DOX)-induced
cardiomyopathy has been demonstrated in mice, normotensive and hypertensive rats,
rabbits, dogs, swine, and humans. These animal models of DOX-induced
cardiomyopathy were found to be highly predictive of DEX activity clinically. In
mice administered maximally tolerated doses of DOX over a period of 7 weeks, the
optimum dose of DEX was from 10:1 to 20:1 (DEX:DOX) given from 30 minutes before
to 15 minutes after DOX. The dose ratio required to reduce the incidence of
moderate to severe cardiomyopathy by 90% in the mouse was more than 20:1 for DOX
and 10:1, 5:1, and 5:1 for epirubicin, daunorubicin, and idarubicin,
respectively. Dexrazoxane was most effective in rats when treatment commenced
with the first and third doses of DOX, but also provided cardioprotection when
started with the sixth of 10 doses of DOX. The cardioprotective activity of DEX
in rats was evident for more than 6 months after completion of DOX dosing.
Results of antitumor studies in several experimental tumor models indicate that
DEX does not interfere with the antineoplastic activity of DOX or other antitumor
drugs. In some case, especially cyclophosphamide, there was a markedly
synergistic antitumor effect when combined with DEX.
PMID- 9768821
TI - Phase I trials of dexrazoxane and other potential applications for the agent.
AB - The clinical development of dexrazoxane (DEX; ICRF-187; Zinecard, Pharmacia and
Upjohn, Kalamazoo, MI) was originally begun using it as an antineoplastic agent.
It had a unique mechanism of action and activity in a variety of in vitro and in
vivo models. Phase I trials with the agent began in January 1979. The phase I
trials indicated that DEX could be safely administered, with leukopenia and
thrombocytopenia being the dose-limiting toxicities, on a number of different
schedules of administration. Some hints of antitumor activity were also noted. In
the phase I studies it was also noted, based on the chelating abilities of DEX,
that the compound caused marked increases in urine clearance of iron and zinc in
patients receiving the agent. That information, plus the information being
generated in preclinical studies that DEX could protect against the
cardiotoxicity induced by anthracyclines (through a decrease in free radical
formation), led to the use of DEX as a cardioprotective agent (as thoroughly
discussed in this supplement). However, in addition to working as a
cardioprotective agent, DEX has other potential applications that are outlined
below and include (1) treatment of patients with acquired immunodeficiency
syndrome-related Kaposi's sarcoma, based on its activity as an angiogenesis
inhibitor; (2) enhancement of the effects of cisplatin, based on its ability to
increase the antiproliferative effects of cisplatin on human ovarian cancer
cells; (3) use for treatment of iron overload states in patients who are allergic
to deferoxamine; (4) treatment of patients with psoriasis; (5) protection from
hyperoxic effects on the lungs; (6) protection from bleomycin-induced pulmonary
fibrosis; (7) attenuation of acetaminophen-induced hepatotoxicity; (8) prevention
of mucositis; and (9) other applications. Clearly, there should be additional
investigations to maximize the usefulness of the very interesting DEX molecule.
PMID- 9768822
TI - Clinical pharmacology of dexrazoxane.
AB - Dexrazoxane is a synthetic bisdiketopiperazine two-ringed compound which
hydrolyzes to an EDTA analog. These rings undergo intracellular hydrolysis to
form the single and double (ICRF-198) chelating forms of the compound by both
enzymatic and non-enzymatic catalysis. These dexrazoxane metabolites are
efficient at stripping the cations from the iron:anthracycline complex. The
disruption of the complex prevents the oxidative damage from free radicals
promoted by this anthracycline complex. Pharmacologic studies of single agent
dexrazoxane (originally studied as an antineoplastic agent) demonstrates an alpha
half-life of approximately 30 minutes and a beta half-life of 2 to 4 hours. When
given in combination with anthracyclines (e.g. doxorubicin or epirubicin) the
pharmacokinetics of dexrazoxane are unchanged. Additional studies of
anthracycline metabolism when given in combination with dexrazoxane, both in
single arm and randomized cross-over studies, have generally shown no change in
anthracycline metabolism, including pharmacokinetic parameters of alpha, beta,
and gamma half-lives, area-under-the-curve, or clearance. There is no
pharmacokinetic interaction of dexrazoxane on anthracycline metabolism and,
therefore, pharmacokinetics cannot account for the cardioprotective effects
described for dexrazoxane.
PMID- 9768823
TI - Adult multicenter trials using dexrazoxane to protect against cardiac toxicity.
AB - Two large multicenter placebo controlled trials (088001 and 088006) in metastatic
breast cancer found a significant cardioprotective effect of dexrazoxane when
administered with doxorubicin. A delayed dose analysis found a protective effect
even after a cumulative dose of doxorubicin of 300 mg/m2. Exploratory analysis
combing the arms on the two studies found a cardioprotective effect of
dexrazoxane either initially or after 300 mg/m2 when administered in patients
older than 65 years, compared to patients receiving only placebo. Also, patients
with an ejection fraction within 10% above the lower limit of normal were
protected with dexrazoxane. Objective response rates were borderline
significantly lower for patients receiving dexrazoxane. Recommendations are to
administer dexrazoxane after 300 mg/m2.
PMID- 9768824
TI - Overview and historical development of dexrazoxane.
AB - Dexrazoxane prevents the dose-limiting cardiotoxicity of the anthracyclines
without reducing their antitumor efficacy and without new adverse side effects.
Dexrazoxane reduces the severity of gastrointestinal symptoms of the
anthracycline containing combination doxorubicin, 5-fluorouracil,
cyclophosphamide and most surprisingly and importantly, dexrazoxane increases the
median survival time of advanced breast cancer responders to the doxorubicin, 5
fluorouracil, cyclophosphamide regimen. The median survival time is doubled as
compared to controls to nearly 3 years.
PMID- 9768825
TI - European trials with dexrazoxane in amelioration of doxorubicin and epirubicin
induced cardiotoxicity.
AB - The ability of dexrazoxane (DEX) to protect against anthracycline-induced
cardiotoxicity has been evaluated in several European studies using either
standard or high-dose regimens. In addition, one randomized trial investigated
the value of cardiac radioimmunoscintigraphy with indium-111 antimyosin
monoclonal antibodies in the early detection of cardiac damage. The results of
these trials demonstrate that DEX is able to ameliorate doxorubicin- and
epirubicin-induced cardiotoxicity, even when high single drug doses are used. The
cardioprotective effect of DEX has been clearly documented by both clinical and
laboratory cardiac evaluation. The use of DEX did not add to the toxicity of the
anthracyclines, nor was there clear evidence of an adverse impact of the agent on
antitumor activity of the chemotherapeutic regimen. Radioimmunoscintigraphy was
very sensitive in detecting anthracycline cardiac damage, but its specificity is
low and it cannot be considered a primary test for guiding anthracycline
treatment.
PMID- 9768826
TI - Efficacy of dexrazoxane as a cardioprotective agent in patients receiving
mitoxantrone- and daunorubicin-based chemotherapy.
AB - Dexrazoxane (DEX) selectively blocks the development of irreversible diffuse
myocardial toxicity induced by anthracyclines and related antitumor agents, such
as mitoxantrone (MTX). Therefore, daunorubicin (DNR) should not be administered
to patients with cumulative DNR doses higher than 550 to 700 mg/m2, which we used
for remission induction and consolidation therapy in patients with acute myeloid
leukemia (AML). To administer further doses of anthracyclines without risks in
seven relapsed AML patients and in one patient with impaired heart functions
receiving consolidation therapy, we used DEX as a cardioprotective agent.
Patients received DEX 30 minutes before DNR 45 mg/m2 or MTX 10 mg/m2 in doses
eight to 13 times higher (DNR) or 30 to 60 times higher (MTX) in the treatment
cycle with 10 high doses (2,000 mg/m2/12 hr) of cytosine arabinoside plus two
doses of DNR or MTX on the fourth and fifth day. When this cycle was used as
reinduction therapy, complete remission was achieved in all five cases. A cycle
of MTX and etoposide was given three times with DEX as consolidation.
Myelotoxicity of the treatment cycles with DEX was similar to the cycles without
it. Two patients received cumulative anthracyclines doses corresponding to more
than 1,300 and 1,000 mg/m2 of DNR, respectively; the remaining five relapsed
patients received 550 to 850 mg/m2 of DNR, all without signs of cardiac toxicity.
Delayed administration of DEX after cumulative doses of DNR 500 mg/m2 in AML
patients at relapse provides cardioprotection against DNR or MTX in combination
with high doses of cytosine arabinoside. This type of chemotherapy seems to be
effective for remission induction in relapsed, heavily pretreated AML patients or
in patients with impaired heart functions.
PMID- 9768827
TI - Use of dexrazoxane and other strategies to prevent cardiomyopathy associated with
doxorubicin-taxane combinations.
AB - Doxorubicin (DOX) plus paclitaxel is an active combination for patients with
metastatic breast cancer, producing objective response in approximately 50% to
90% of patients. The drugs may be combined using different doses and schedules.
When 60 mg/m2 of DOX is given by intravenous bolus followed 15 to 30 minutes
later by 200 mg/m2 of paclitaxel (given as a 3-hour infusion), approximately 20%
of patients will have a substantial decrease in their left ventricular ejection
fraction below normal after four cycles of therapy (or a cumulative DOX dose of
240 mg/m2). Approximately 4% will have symptoms of congestive heart failure.
After eight cycles of therapy, or a cumulative DOX dose of 480 mg/m2,
approximately 50% of patients will have a decrease in left ventricular ejection
fraction below normal and 20% of patients will develop clinical evidence of
congestive heart failure. This is a higher than expected incidence of congestive
heart failure when compared with retrospectively derived historical data.
Paclitaxel increases the area under the curve of DOX by approximately 30% when
given before or after DOX, providing an explanation for this phenomenon. Several
strategies seem to be associated with a reduced incidence of cardiac toxicity,
including the use of dexrazoxane with the combination, restricting the cumulative
DOX dose to < or = 360 mg/m2, increasing the interval between administration of
the drugs, and use of other taxanes (eg, docetaxel) or other less cardiotoxic
anthracyclines (eg, epirubicin or liposomal DOX). Most of these strategies were
evaluated in noncomparative phase I/II trials, and further study will be required
to determine the role of anthracycline-taxane combinations in the management of
patients with operable and advanced breast cancer, and to determine a combination
that has the most favorable therapeutic index.
PMID- 9768828
TI - Epidemiology of anthracycline cardiotoxicity in children and adults.
AB - Anthracyclines, potent cytotoxic agents used to treat a broad spectrum of
malignancies, are limited in their use by an attendant risk of cardiotoxicity.
Malignancies affect all age ranges, and anthracyclines are used in all age
ranges, thereby exposing a broad population of patients to the development of
heart disease. For some treated patients, anthracyclines affect cardiac muscle,
resulting in cardiomyopathy. The type and degree of cardiomyopathy, as well as
when during or after treatment the condition occurs, are dependent on what risk
factors are present. Age is a major risk factor. Children and adults may develop
restrictive and dilated cardiomyopathy. The length of subsequent survival and
amount of subsequent somatic growth may influence late anthracycline-associated
cardiac outcome. Early cardiotoxicity, occurring during or within 1 year of
completion of treatment, is the largest risk factor for the development of late
cardiotoxicity, which occurs beyond a year of completion of treatment. Risk
factors, which appear to be specific for early cardiotoxicity in children,
include black race, trisomy 21, and the use of amsacrine therapy after
anthracycline therapy. More cardiotoxic effects are seen in survivors of
childhood cancer, the longer from completion of treatment a patient is followed.
Cumulative as well as peak anthracycline doses affect adults and children alike,
and cardiotoxicity occurs early and late. In adults, left ventricular
contractility is affected by anthracyclines. Children may manifest impairment of
left ventricular contractility and increased afterload due to thinning of left
ventricular walls. Patients with an early presentation of depressed left
ventricular contractility are likely to show progression of cardiac disease with
time. In addition, female gender appears to affect early and late cardiotoxicity
in both adults and children, although this risk factor has been described
predominantly in the survivors of childhood cancer. Thus, although anthracycline
chemotherapy has improved overall survivorship of patients with cancer, there is
a significant risk of cardiotoxicity associated with this class of drugs.
PMID- 9768829
TI - Ameliorating anthracycline cardiotoxicity in children with cancer: clinical
trials with dexrazoxane.
AB - Anthracyclines have major activity against a broad range of childhood cancers.
Concern over the risk of long-term cardiotoxicity associated with their use has
called into question the role of these agents in the frontline treatment of many
patients. Dexrazoxane was developed as a specific cardioprotectant "antidote"
which can prevent anthracycline cardiotoxicity without inhibiting its antitumor
effect. To date, four clinical trials of dexrazoxane have been conducted in
pediatric cancer patients (primarily with sarcomas). The two largest series,
conducted at the National Cancer Institute Pediatric Branch, demonstrated
significant short-term cardioprotection with no evidence of interference with
antitumor activity. Additional clinical trials are ongoing, or planned to open
shortly, to better evaluate the role of dexrazoxane in the treatment of childhood
cancer. These studies, being conducted on larger numbers of patients with better
prospects for cure, are expected to definitviely answer the outstanding questions
of whether preventing short-term, subclinical cardiotoxicity will translate into
long-term cardioprotection, and whether the use of dexrazoxane interferes with
the anti-tumor efficacy of doxorubicin-containing regimens.
PMID- 9768830
TI - Antineoplastic activity of continuous exposure to dexrazoxane: potential new role
as a novel topoisomerase II inhibitor.
AB - Although originally developed as an antitumor agent in the 1970s, dexrazoxane
(DEX) is currently used as a cardioprotective agent in combination with
doxorubicin (DOX). Due to concerns about anthracycline-induced cardiotoxicity at
higher cumulative doses, many investigators have chosen to administer DOX by
prolonged infusion. Therefore, with the ultimate goal of combining infusional DEX
and DOX, we performed a phase I study of intravenous DEX alone as a 96-hour
infusion. Surprisingly, the maximum tolerated dose of DEX identified in this
study was 10- to 15-fold lower than previously determined using different
schedules of administration. Results of pharmacokinetic studies in support of the
trial have found that steady-state DEX plasma concentrations in the range of 4 to
5 micromol/L can be achieved safely. Because previous experiments have explored
the ability of DEX to inhibit the catalytic activity topoisomerase II at low
micromolar concentrations and due to a lack of in vitro cytotoxicity data for
long-term exposures, we performed further laboratory studies to provide a context
for our pharmacokinetic findings. As a result of these correlative studies, we
have found that prolonged exposures to DEX are cytotoxic to human leukemic cells
at concentrations that are clinically achievable.
PMID- 9768831
TI - Identifying the missing links: genes that connect neural induction and primary
neurogenesis in vertebrate embryos.
PMID- 9768832
TI - Activity and synaptic receptor targeting: the long view.
PMID- 9768833
TI - Genes for normal behavioral variation: recent clues from flies and worms.
PMID- 9768834
TI - Neuroscience of addiction.
PMID- 9768835
TI - Tomosyn binds t-SNARE proteins via a VAMP-like coiled coil.
PMID- 9768836
TI - A novel signaling pathway from rod photoreceptors to ganglion cells in mammalian
retina.
AB - Current understanding suggests that mammalian rod photoreceptors connect only to
an ON-type bipolar cell. This rod-specific bipolar cell excites the All amacrine
cell, which makes connections to cone-specific bipolar cells of both ON and OFF
type; these, in turn, synapse with ganglion cells. Recent work on rabbit retina
has shown that rod signals can also reach ganglion cells without passing through
the rod bipolar cell. This route was thought to be provided by electrical gap
junctions, through which rods signal directly to cones and thence to cone bipolar
cells. Here, we show that the mouse retina also provides a rod pathway bypassing
the rod bipolar cell, suggesting that this is a common feature in mammals.
However, this alternative pathway does not require cone photoreceptors; it is
perfectly intact in a transgenic mouse whose retina lacks cones. Instead, the
results can be explained if rods connect directly to OFF bipolar cells.
PMID- 9768837
TI - Phosphorylation and inhibition of olfactory adenylyl cyclase by CaM kinase II in
Neurons: a mechanism for attenuation of olfactory signals.
AB - Acute desensitization of olfactory signaling is a critical property of the
olfactory system that allows animals to detect and respond to odorants.
Correspondingly, an important feature of odorant-stimulated cAMP increases is
their transient nature, a phenomenon that may be attributable to the unique
regulatory properties of the olfactory adenylyl cyclase (AC3). AC3 is stimulated
by receptor activation and inhibited by Ca2+ through Ca2+/calmodulin kinase II
(CaMKII) phosphorylation at Ser-1076. Since odorant-stimulated cAMP increases are
accompanied by elevated intracellular Ca2+, CaMKII inhibition of AC3 may
contribute to termination of olfactory signaling. To test this hypothesis, we
generated a polyclonal antibody specific for AC3 phosphorylated at Ser-1076. A
brief exposure of mouse olfactory cilia or primary olfactory neurons to odorants
stimulated phosphorylation of AC3 at Ser-1076. This phosphorylation was blocked
by inhibitors of CaMKII, which also ablated cAMP decreases associated with
odorant-stimulated cAMP transients. These data define a novel mechanism for
termination of olfactory signaling that may be important in olfactory responses.
PMID- 9768838
TI - Regulation of class I MHC gene expression in the developing and mature CNS by
neural activity.
AB - To elucidate molecular mechanisms underlying activity-dependent synaptic
remodeling in the developing mammalian visual system, we screened for genes whose
expression in the lateral geniculate nucleus (LGN) is regulated by spontaneously
generated action potentials present prior to vision. Activity blockade did not
alter expression in the LGN of 32 known genes. Differential mRNA display,
however, revealed a decrease in mRNAs encoding class I major histocompatibility
complex antigens (class I MHC). Postnatally, visually driven activity can
regulate class I MHC in the LGN during the final remodeling of retinal ganglion
cell axon terminals. Moreover, in the mature hippocampus, class I MHC mRNA levels
are increased by kainic acid-induced seizures. Normal expression of class I MHC
mRNA is correlated with times and regions of synaptic plasticity, and
immunohistochemistry confirms that class I MHC is present in specific subsets of
CNS neurons. Finally, beta2-microglobulin, a cosubunit of class I MHC, and
CD3zeta, a component of a receptor complex for class I MHC, are also expressed by
CNS neurons. These observations indicate that class I MHC molecules, classically
thought to mediate cell-cell interactions exclusively in immune function, may
play a novel role in neuronal signaling and activity-dependent changes in
synaptic connectivity.
PMID- 9768839
TI - BDNF has opposite effects on the quantal amplitude of pyramidal neuron and
interneuron excitatory synapses.
AB - Recently, we have identified a novel form of synaptic plasticity that acts to
stabilize neocortical firing rates by scaling the quantal amplitude of AMPA
mediated synaptic inputs up or down as a function of neuronal activity. Here, we
show that the effects of activity blockade on quantal amplitude are mediated
through the neurotrophin brain-derived neurotrophic factor (BDNF). Exogenous BDNF
prevented, and a TrkB-IgG fusion protein reproduced, the effects of activity
blockade on pyramidal quantal amplitude. BDNF had opposite effects on pyramidal
neuron and interneuron quantal amplitudes and modified the ratio of pyramidal
neuron to interneuron firing rates. These data demonstrate a novel role for BDNF
in the homeostatic regulation of excitatory synaptic strengths and in the
maintenance of the balance of cortical excitation and inhibition.
PMID- 9768840
TI - The cloned capsaicin receptor integrates multiple pain-producing stimuli.
AB - Capsaicin, the main pungent ingredient in "hot" chili peppers, elicits buming
pain by activating specific (vanilloid) receptors on sensory nerve endings. The
cloned vanilloid receptor (VR1) is a cation channel that is also activated by
noxious heat. Here, analysis of heat-evoked single channel currents in excised
membrane patches suggests that heat gates VR1 directly. We also show that protons
decrease the temperature threshold for VR1 activation such that even moderately
acidic conditions (pH < or = 5.9) activate VR1 at room temperature. VR1 can
therefore be viewed as a molecular integrator of chemical and physical stimuli
that elicit pain. Immunocytochemical analysis indicates that the receptor is
located in a neurochemically heterogeneous population of small diameter primary
afferent fibers. A role for VR1 in injury-induced hypersensitivity at the level
of the sensory neuron is presented.
PMID- 9768841
TI - Cell type and pathway dependence of synaptic AMPA receptor number and variability
in the hippocampus.
AB - It has been suggested that some glutamatergic synapses lack functional AMPA
receptors. We used quantitative immunogold localization to determine the number
and variability of synaptic AMPA receptors in the rat hippocampus. Three classes
of synapses show distinct patterns of AMPA receptor content. Mossy fiber synapses
on CA3 pyramidal spines and synapses on GABAergic interneurons are all
immunopositive, have less variability, and contain 4 times as many AMPA receptors
as synapses made by Schaffer collaterals on CA1 pyramidal spines and by
commissural/ associational (C/A) terminals on CA3 pyramidal spines. Up to 17% of
synapses in the latter two connections are immunonegative. After calibrating the
immunosignal (1 gold = 2.3 functional receptors) at mossy synapses of a 17-day
old rat, we estimate that the AMPA receptor content of C/A synapses on CA3
pyramidal spines ranges from <3 to 140. A similar range is found in adult
Schaffer collateral and C/A synapses.
PMID- 9768842
TI - Activation of AMPA, kainate, and metabotropic receptors at hippocampal mossy
fiber synapses: role of glutamate diffusion.
AB - Glutamatergic transmission at mossy fiber (MF) synapses on CA3 pyramidal neurons
in the hippocampus is mediated by AMPA, kainate, and NMDA receptors and undergoes
presynaptic modulation by metabotropic glutamate receptors. The recruitment of
different receptors has thus far been studied by altering presynaptic stimulation
to modulate glutamate release and interfering pharmacologically with receptors
and transporters. Here, we introduce two novel experimental manipulations that
alter the fate of glutamate molecules following release. First, an enzymatic
glutamate scavenger reduces the postsynaptic response as well as presynaptic
modulation by metabotropic receptors. At physiological temperature, however, the
scavenger is effective only when glutamate uptake is blocked, revealing a role of
active transport in both synaptic and extrasynaptic communication. Second, AMPA
and kainate receptor-mediated postsynaptic signals are enhanced when
extracellular diffusion is retarded by adding dextran to the perfusion solution,
as is feedback modulation by metabotropic receptors, suggesting that the
receptors are not saturated under baseline conditions. These results show that
manipulating the spatiotemporal profile of glutamate following exocytosis can
alter the involvement of different receptors in synaptic transmission.
PMID- 9768843
TI - Role of the carboxy-terminal region of the GluR epsilon2 subunit in synaptic
localization of the NMDA receptor channel.
AB - The synaptic localization of the N-methyl-D-aspartate (NMDA) type glutamate
receptor (GluR) channel is a prerequisite for synaptic plasticity in the brain.
We generated mutant mice carrying the carboxy-terminal truncated GluR epsilon2
subunit of the NMDA receptor channel. The mutant mice died neonatally and failed
to form barrelette structures in the brainstem. The mutation greatly decreased
the NMDA receptor-mediated component of hippocampal excitatory postsynaptic
potentials and punctate immunofluorescent labelings of GluR epsilon2 protein in
the neuropil regions, while GluR epsilon2 protein expression was comparable.
Immunostaining of cultured cerebral neurons showed the reduced punctate staining
of the truncated GluR epsilon2 protein at synapses. These results suggest that
the carboxy-terminal region of the GluRepsilon2 subunit is important for
efficient clustering and synaptic localization of the NMDA receptor channel.
PMID- 9768845
TI - CaMKIIbeta functions as an F-actin targeting module that localizes
CaMKIIalpha/beta heterooligomers to dendritic spines.
AB - Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a serine/threonine
protein kinase that regulates long-term potentiation and other forms of neuronal
plasticity. Functional differences between the neuronal CaMKIIalpha and
CaMKIIbeta isoforms are not yet known. Here, we use green fluorescent protein
tagged (GFP-tagged) CaMKII isoforms and show that CaMKIIbeta is bound to F-actin
in dendritic spines and cell cortex while CaMKIIalpha is largely a cytosolic
enzyme. When expressed together, the two isoforms form large heterooligomers, and
a small fraction of CaMKIIbeta is sufficient to dock the predominant CaMKIIalpha
to the actin cytoskeleton. Thus, CaMKIIbeta functions as a targeting module that
localizes a much larger number of CaMKIIalpha isozymes to synaptic and
cytoskeletal sites of action.
PMID- 9768844
TI - Novel anchorage of GluR2/3 to the postsynaptic density by the AMPA receptor
binding protein ABP.
AB - We report the cloning of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic
acid (AMPA) receptor-binding protein (ABP), a postsynaptic density (PSD) protein
related to glutamate receptor-interacting protein (GRIP) with two sets of three
PDZ domains, which binds the GluR2/3 AMPA receptor subunits. ABP exhibits
widespread CNS expression and is found at the postsynaptic membrane. We show that
the protein interactions of the ABP/GRIP family differ from the PSD-95 family,
which binds N-methyl-D-aspartate (NMDA) receptors. ABP binds to the GluR2/3 C
terminal VKI-COOH motif via class II hydrophobic PDZ interactions, distinct from
the class I PSD-95-NMDA receptor interaction. ABP and GRIP also form homo- and
heteromultimers through PDZ-PDZ interactions but do not bind PSD-95. We suggest
that the ABP/GRIP and PSD-95 families form distinct scaffolds that anchor,
respectively, AMPA and NMDA receptors.
PMID- 9768846
TI - Dissociation between Ca2+-triggered synaptic vesicle exocytosis and clathrin
mediated endocytosis at a central synapse.
AB - We have tested whether action potential-evoked Ca2+ influx is required to
initiate clathrin-mediated synaptic vesicle endocytosis in the lamprey
reticulospinal synapse. Exo- and endocytosis were temporally separated by a
procedure involving tonic action potential stimulation and subsequent removal of
extracellular Ca2+ (Ca2+e). A low concentration of Ca2+ ([Ca2+]e of 11 microM)
was found to be required for the induction of early stages of endocytosis.
However, the entire endocytic process, from the formation of clathrin-coated
membrane invaginations to the generation of synaptic vesicles, proceeded in the
absence of action potential-mediated Ca2+ entry. Our results indicate that the
membrane of synaptic vesicles newly incorporated in the plasma membrane is a
sufficient trigger of clathrin-mediated synaptic vesicle endocytosis.
PMID- 9768847
TI - The activation gate of a voltage-gated K+ channel can be trapped in the open
state by an intersubunit metal bridge.
AB - Voltage-activated K+ channels are integral membrane proteins containing a
potassium-selective transmembrane pore gated by changes in the membrane
potential. This activation gating (opening) occurs in milliseconds and involves a
gate at the cytoplasmic side of the pore. We found that substituting cysteine at
a particular position in the last transmembrane region (S6) of the homotetrameric
Shaker K+ channel creates metal binding sites at which Cd2+ ions can bind with
high affinity. The bound Cd2+ ions form a bridge between the introduced cysteine
in one channel subunit and a native histidine in another subunit, and the bridge
traps the gate in the open state. These results suggest that gating involves a
rearrangement of the intersubunit contacts at the intracellular end of S6. The
recently solved structure of a bacterial K+ channel shows that the S6 homologs
cross in a bundle, leaving an aperture at the bundle crossing. In the context of
this structure, the metal ions form a bridge between a cysteine above the bundle
crossing and a histidine below the bundle crossing in a neighboring subunit. Our
results suggest that gating occurs at the bundle crossing, possibly through a
change in the conformation of the bundle itself.
PMID- 9768848
TI - Biotinylation of single cysteine mutants of the glutamate transporter GLT-1 from
rat brain reveals its unusual topology.
AB - In the central nervous system, (Na+ + K+)-coupled glutamate transporters restrict
the neurotoxicity of this transmitter and limit the duration of synaptic
excitation at some synapses. The various isotransporters exhibit a particularly
high homology in an extended hydrophobic domain of ill-defined topology that
contains several determinants involved in ion and transmitter binding. Here, we
describe the determination of the membrane topology of the cloned astroglial
glutamate transporter GLT-1. A series of functional transporters containing
single cysteines was engineered. Their topological disposition was determined by
using a biotinylated sulfhydryl reagent. The glutamate transporter has eight
transmembrane domains long enough to span the membrane as et heiices. Strikingly,
between the seventh and eighth domains, a structure reminiscent of a pore loop
and an outward-facing hydrophobic linker are positioned.
PMID- 9768849
TI - Polyglutamine-expanded human huntingtin transgenes induce degeneration of
Drosophila photoreceptor neurons.
AB - Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder.
Disease alleles contain a trinucleotide repeat expansion of variable length,
which encodes polyglutamine tracts near the amino terminus of the HD protein,
huntingtin. Polyglutamine-expanded huntingtin, but not normal huntingtin, forms
nuclear inclusions. We describe a Drosophila model for HD. Amino-terminal
fragments of human huntingtin containing tracts of 2, 75, and 120 glutamine
residues were expressed in photoreceptor neurons in the compound eye. As in human
neurons, polyglutamine-expanded huntingtin induced neuronal degeneration. The age
of onset and severity of neuronal degeneration correlated with repeat length, and
nuclear localization of huntingtin presaged neuronal degeneration. In contrast to
other cell death paradigms in Drosophila, coexpression of the viral antiapoptotic
protein, P35, did not rescue the cell death phenotype induced by polyglutamine
expanded huntingtin.
PMID- 9768850
TI - In situ detection of chromosome bridge formation and delayed reproductive death
in normal human embryonic cells surviving X irradiation.
AB - We investigated delayed reproductive death and chromosome bridge formation in
mitotic cells in colonies of normal human embryonic cells which survived exposure
to 6 Gy of X rays. Eighteen primary clones each derived from control and
irradiated cultures were isolated and secondary colonies were grown up. Six of
the primary clones surviving the irradiation showed significantly lower cloning
efficiencies than the control clones (P < 0.001), while the rest of the surviving
clones showed a cloning efficiency similar to those of the control clones. The
average cloning efficiency of control and surviving clones was 16.4 and 7.2%,
respectively. Reduced cloning efficiencies were also observed in the tertiary
colony formation, indicating that the persistent decrease in cloning efficiency
was inherited over 40 generations after X irradiation in normal human cells. Five
of nine primary clones surviving the irradiation also frequently contained
multiple giant cells in the colonies, while this was a rare event in the progeny
of control clones. Furthermore, we analyzed in situ chromosome segregation in
anaphase cells appearing during the formation of the secondary colonies. A
significantly higher frequency of chromosome bridge formation was found in four
of the surviving clones which received 6 Gy (P < 0.001), and the frequency of
micronuclei was also increased in the surviving clones. These results provide
evidence that genetic instability is induced in normal human embryonic cells by
low-LET radiation, and that misrejoining of the broken chromosome ends is
increased in the progeny of cells surviving X irradiation.
PMID- 9768851
TI - The nucleus is the target for radiation-induced chromosomal instability.
AB - We have previously described chromosomal instability in cells of a human-hamster
hybrid cell line after exposure to X rays. Chromosomal instability in these cells
is characterized by the appearance of novel chromosomal rearrangements multiple
generations after exposure to ionizing radiation. To identify the cellular
target(s) for radiation-induced chromosomal instability, cells were treated with
125I-labeled compounds and frozen. Radioactive decays from 125I cause damage to
the cell primarily at the site of their decay, and freezing the cells allows
damage to accumulate in the absence of other cellular processes. We found that
the decay of 125I-iododeoxyuridine, which is incorporated into the DNA, caused
chromosomal instability. While cell killing and first-division chromosomal
rearrangements increased with increasing numbers of 125I decays, the frequency of
chromosomal instability was independent of dose. Chromosomal instability could
also be induced from incorporation of 125I-iododeoxyuridine without freezing the
cells for accumulation of decays. This indicates that DNA double-strand breaks in
frozen cells resulting from 125I decays failed to lead to instability.
Incorporation of an 125I-labeled protein (125I-succinyl-concanavalin A), which
was internalized into the cell and/or bound to the plasma membrane, neither
caused chromosomal instability nor potentiated chromosomal instability induced by
125I-iododeoxyuridine. These results show that the target for radiation-induced
chromosomal instability in these cells is the nucleus.
PMID- 9768852
TI - Radioprotection against lethal damage caused by chronic irradiation with
radionuclides in vitro.
AB - To examine the capacity of chemical protectors to mitigate damage caused by
chronic irradiation by incorporated radionuclides in vitro, cells must be
maintained in the presence of the protector during the course of the irradiation.
Such long exposures to chemical protectors at concentrations high enough to
afford protection usually results in extreme chemotoxicity. To overcome this
problem, experimental conditions were developed to allow Chinese hamster V79
cells to be maintained in 5% DMSO for prolonged periods (up to 72 h) with no
observable chemotoxicity. Under these conditions, the capacity of DMSO to protect
against damage to V79 cells caused by unbound 32P and 3H2O and DNA-incorporated
(131)IdU, [3H]dThd and 125IdU was examined. The dose modification factors for
32P, 3H2O, (131)IdU, [3H]dThd and 125IdU were 2.6+/-0.5, 2.3+/-0.3, 1.0+/-0.1,
1.16+/-0.07 and 1.07+/-0.02, respectively. These results show that 5% DMSO is
capable of protecting cultured V79 cells against lethal damage caused by beta
particles emitted by unbound 32P and 3H2O, whereas little or no protection is
afforded against damage caused by beta particles emitted by DNA-incorporated
(131)I and 3H or low-energy Auger electrons emitted by DNA-incorporated 125I.
PMID- 9768853
TI - Biological dosimetry of beta-ray exposure from tritium using chromosome
translocations in human lymphocytes analyzed by fluorescence in situ
hybridization.
AB - Radiation exposures from tritium make up a substantial fraction of the
occupational and accidental radiation exposures associated with the nuclear power
industry. Tritiated water, the most abundant form of tritium, is of particular
interest because it is readily taken up by human cells and its irradiation of the
cells is spread over a period of days. To approximate the prolonged exposure and
the conditions that the cells of an individual would experience in vivo, we
irradiated human lymphocytes with tritiated water for 48 h in a 1:1 blood:medium
mix. For estimation of the tritium beta-ray dose, a cellular water content of
0.78, based on measurements of human lymphoblastoid cells in culture medium, was
used. A modified dose calculation formula was developed for the radiation
exposure conditions. A total of 48,014 metaphases (14,482 in irradiated samples
and 33,532 in control, unirradiated samples) in human lymphocytes cultured for 72
h after exposure were analyzed for chromosome translocations using fluorescence
in situ hybridization. The linear slope (alpha coefficient) of the dose-response
curve was measured to be (3.93+/-0.42) x 10(-2) and (5.26+/-0.48) x 10(-2)
translocations per cell per gray for complete translocations (tc) and complete
translocations plus incomplete translocations [ti(Ab)], respectively, when the
data were fitted to a linear model using a weighted least-squares method. The
alpha coefficient for tc is significantly lower than that for conventionally
measured dicentrics after tritium beta irradiation, but the alpha coefficient for
tc + ti(Ab) does not differ significantly from that for dicentrics. This is in
agreement with theoretical considerations. The importance of scoring criteria is
stressed. The frequency of tc + ti(Ab) is proposed to be a reliable biodosimeter
for tritium exposures, and its practical use in a dose reconstruction is
presented.
PMID- 9768854
TI - Radiation fields backscattered from material interfaces: I. Biological
effectiveness.
AB - Confluent cultures of CHO-K1 and CHO-xrs5 cells were irradiated attached to 6
microm Mylar with 137Cs gamma rays and 200 kVp X rays adjacent to scattering
materials consisting of polystyrene, glass, aluminum, copper, tin and lead. The
absorbed dose in cell nuclei was estimated from measurements of backscattered
dose made with a parallel-plate ion chamber with a 5-microm Mylar window and a
gas volume whose thickness was equivalent to approximately 2.6 microm of cells or
tissue. Cell inactivation after various doses was measured by clonogenic assays
after trypsinization and enumeration. Survival curves constructed from data
pooled from at least two independent experiments were best fitted to a linear
quadratic (LQ) or a linear equation for CHO-K1 and CHO-xrs5 cells, respectively.
An average distance of 9.3+/-1.9 microm from the scattering surfaces to the
midline of nuclei for both the cell lines was estimated from electron micrographs
of fixed cell sections. The major differences in biological effect observed when
the cells were irradiated adjacent to these materials could be largely explained
by the differences in the physical dose. Further analyses using the LQ equation
suggested additional biological effects with implications for the mechanisms
involved. CHO-K1 cells showed a small but consistent increase in the low-dose
(alpha-inactivation coefficient) mechanism for both radiations scattered from
high-Z material. An increased value of the alpha coefficient suggests an increase
in RBE which could be associated with a higher proportion of low-energy and track
end electrons in these fields. The radiation fields which produced maximum single
hit killing in CHO-K1 cells also produced less killing by the quadratic (beta
inactivation coefficient) mechanism. In contrast, when similarly irradiated, CHO
xrs5 cells exhibited significantly lower alpha coefficients of inactivation. The
mechanistic basis for this opposite effect of backscattered radiations in these
cell lines is as yet unknown.
PMID- 9768855
TI - Recovery from sublethal damage is reversibly inhibited by hypertonic saline: the
effects of 0.23 M sodium chloride.
AB - We previously showed that 0.23 M NaCl was able to fix slowly repairing
potentially lethal damage (PLD), and that this slowly repairing PLD is distinct
from rapidly repairing PLD that is sensitive to 0.5 M NaCl (Ikebuchi et al.,
Radiat. Res. 141, 19-27, 1995). In the present study, the effect of 0.23 M NaCl
on repair of sublethal damage (SLD) was examined in cells of three rodent cell
lines with normal radiosensitivity (Chinese hamster V79, BALB/c 3T3, RD13B2) and
two radiosensitive lines derived from severe combined immunodeficient (scid)
mice. Repair of SLD was detected as an increase in survival when the radiation
dose was fractionated with an interval of incubation between the two doses.
Repair of SLD occurred in V79 and BALB/c 3T3 cells but did not occur in the two
scid cell lines which were defective in repair of double-strand breaks (DSBs),
demonstrating that repair of DSBs is involved in repair of SLD. This was
confirmed by the observation that repair of SLD occurred in RD13B2 cells, the
scid line which had regained the ability to repair DSBs. When the V79 and BALB/c
3T3 cells were treated with 0.23 M NaCl during the interval between the split
doses, repair of SLD was completely inhibited. On the other hand, repair of SLD
occurred when the cells were incubated in culture medium between the treatment
with 0.23 M NaCl and the second dose. From these observations, it is concluded
that the inhibition of repair of SLD by 0.23 M NaCl is reversible, which is in
contrast to the irreversible inhibition of repair of PLD by 0.23 M NaCl found
previously. In addition, the fact that scid cells that were shown to have the
ability to repair PLD that is sensitive to 0.23 M NaCl had little capacity to
repair SLD suggests that there may be different processes involved in the two
types of cellular repair.
PMID- 9768856
TI - Differential sensitivity of three sublines of the rat Dunning prostate tumor
system R3327 to radiation and/or local tumor hyperthermia.
AB - To better understand the relationship of the growth characteristics of tumor
tissues and their response to ionizing radiation alone and in combination with
local tumor hyperthermia, we compared three different tumor sublines of the
Dunning rat prostate carcinoma R3327. This report includes results obtained with
the anaplastic AT1 subline (volume doubling time 5.2 days), the moderately
differentiated mucin-secreting HI subline (volume doubling time about 9 days) and
the well-differentiated, hormone-dependent H subline (volume doubling time about
17 days). The effects of single doses of photons (10 to 40 Gy) with and without
local tumor hyperthermia (35 min immersion at 43.5 degrees C) were quantified by
growth delay. The time to reach five times the volume at the time of treatment
after 30 Gy alone was found to be 56.0, 134.9 and 184.0 days for the R3327-AT1,
HI and H tumors, respectively. The R3327-H tumor was more radiosensitive than the
AT1 or HI subline. Five of nine R3327-H tumors were controlled locally with a
single dose of photons (40 Gy). Local tumor hyperthermia alone induced growth
delay in both differentiated tumors, while the anaplastic tumor subline did not
respond. Combined treatment modalities with heat applied directly after
irradiation revealed isoeffective thermal enhancement ratios for 30 Gy which
decreased from 1.59 for the AT1 tumor and 1.42 for the HI tumor to 1.23 in the
well-differentiated subline R3327-H.
PMID- 9768857
TI - Moderate doses of intraoperative radiation severely suppress early strength of
anastomoses in the rat colon.
AB - Intraoperative irradiation appears to be a valuable addition to the modalities
available to treat patients with large bowel cancer. However, its potential
effect on healing of anastomoses has not been investigated extensively. For this
purpose, male Wistar rats underwent colonic resection. Subsequently, 1 cm of each
bowel end was irradiated with doses of 10, 15, 20 or 25 Gy and intestinal
continuity was restored. After 3 or 7 days, animals were killed and the
anastomoses were analyzed for bursting pressure (intraluminal force), breaking
strength (longitudinal force) and hydroxyproline content. Intraoperative
irradiation led to a massive (40-70%) and significant (P < 0.025) reduction in
bursting pressure 3 days after operation compared to the control group for every
dose used. After 7 days, the bursting site was outside the area of the
anastomosis in all groups. The breaking strength at day 3 was also reduced, even
after 10 Gy. At day 7, when tearing still occurred in the wound area, the
breaking strength was still significantly lower in the 15- and 25-Gy groups than
in the control group. The hydroxyproline content of the anastomoses was
significantly reduced only after irradiation with the higher doses. Thus
intraoperative irradiation constitutes a threat to early strength of anastomoses
in the rat colon, and even at moderate doses it may threaten the integrity of the
anastomosis.
PMID- 9768858
TI - Effects of volume irradiated on the function of the canine ureter.
AB - This study was designed to investigate the influence of the volume irradiated on
the probability of ureteral complications and to provide data for volume
modeling. One hundred thirty-four purpose-bred beagle dogs received single
intraoperative doses of 6 MeV electrons ranging from 12 to 54 Gy to three lengths
of ureter: 2, 4 or 8 cm. The response was evaluated by excretory urography. The
ED50 was 21.9 Gy (95% CI 13.3-30 Gy) for 8 cm 3 years after treatment. The
estimated ED50's were greater than 43 Gy for 4 cm and 85 Gy for 2 cm. Reducing
the length of ureter irradiated from 8 cm to 4 cm increased the ED50 for ureteral
dilation by at least a factor of 2, while reduction from 8 cm to 2 cm increased
the ED50 by at least a factor of 4. The ED50 for renal injury secondary to
stenosis was 30.5 Gy (95% CI 17.2-232 Gy) when an 8-cm field was irradiated.
There was a significant effect of volume irradiated on the frequency of ureteral
stenosis. Reducing the length of ureter included in the treatment field should
allow delivery of higher doses to tumors without increased complications.
PMID- 9768859
TI - Induction of mammary tumors in rats by single-dose gamma irradiation at different
ages.
AB - The effect of age at exposure on induction of mammary tumors was studied in
female rats of the inbred WAG/Rij strain. Groups of 40 animals were exposed to a
single total-body dose of 1 or 2 Gy of 137Cs gamma radiation at ages of 8, 12,
16, 22, 36 or 64 weeks and were observed for life. Mammary tumors, identified as
nodules persisting and growing for 6 weeks, were resected and classified
histologically as carcinoma or fibroadenoma. The age-specific incidence of
mammary carcinoma was compared with that in a group of 120 unirradiated control
rats, using lifetime statistical analysis with both parametric and nonparametric
methods. The excess normalized risk of carcinoma was 0.9 for 1 Gy and 2.2 for 2
Gy in age groups 8-36 weeks, with no significant differences between the age
groups. However, irradiation at 64 weeks yielded fewer carcinomas than in the
controls, the excess normalized risk being -0.7 and -0.3 for 1 and 2 Gy,
respectively. The occurrence of one or more fibroadenomas did not influence the
incidence of carcinoma. The present data agree closely with the results reported
previously for rats irradiated at age 8 or 17 weeks with a dose of 1.2 Gy. The
reduced risk of radiation exposure at midlife is consistent with the available
epidemiological data for exposed women. Although our findings have been obtained
with a single total-body dose that is several orders of magnitude higher than the
multiple doses delivered to the mammary gland during mammography, it is suggested
that radiological screening for mammary cancer after the age of menopause will
not increase the normal incidence of breast cancer.
PMID- 9768860
TI - The influence of estrogen treatment on induction of mammary carcinoma in rats by
single-dose gamma irradiation at different ages.
AB - The effect of age at exposure on induction of mammary carcinoma was studied in
female rats of the inbred WAG/Rij strain that were treated with estrogen. Groups
of 40 animals were exposed to a single total-body dose of 1 or 2 Gy of 137Cs
gamma radiation at age 8, 10, 12, 15, 22, 36 or 64 weeks. Hormone levels in the
animals were increased by implantation of a pellet containing Estradiol-17beta 2
weeks prior to irradiation. Animals were killed when moribund. All mammary tumors
were resected and classified histologically as carcinoma or fibroadenoma. The age
specific incidence of mammary carcinoma was compared with that in control groups
of unirradiated estrogen-treated rats using lifetime statistical analysis with
both parametric and nonparametric methods. The excess normalized risk of
carcinoma was 7.7 for both 1 and 2 Gy in the age groups 8-15 weeks, with no
significant differences between the age groups. However, in the age groups 22-64
weeks, the excess normalized risk decreased with increasing age at exposure.
Irradiation at 64 weeks yielded fewer carcinomas than in the controls, with an
excess normalized risk of -0.6 for both 1 and 2 Gy. The excess normalized risk
was 10-80 in estrogen-treated controls compared to untreated rats. The present
data agree with the results reported previously for estrogen-treated rats
irradiated at ages 8 or 17 weeks with doses of 0.3 or 1.2 Gy. The reduced risk of
radiation exposure at midlife observed in this study in hormone-treated rats has
also been reported for animals not treated with estrogens. The present findings
support the earlier conclusion that radiological screening for mammary cancer
after the age of menopause will not increase the normal incidence of breast
cancer. Estrogen treatment at midlife may increase the risk of breast cancer in
women using replacement estrogens during and after menopause.
PMID- 9768861
TI - Chromosome aberrations in radiation workers with internal deposits of plutonium.
AB - Chromosome analysis of G-banded peripheral blood lymphocytes was performed on two
groups of plutonium workers with 20-50% and >50% maximum permissible body burdens
(MPBB) of plutonium from the British Nuclear Fuels plc (BNFL) facility at
Sellafield, UK, 10 years after an earlier study had reported increases in both
symmetrical and asymmetrical aberrations. For each plutonium exposure group there
was a significant difference in frequencies of symmetrical aberrations between
plutonium workers, workers with similar histories of exposure to mainly external
gamma radiation but with little or no intakes of plutonium, and controls with
negligible exposure (<50 mSv). In contrast, no significant differences for
asymmetrical aberrations were found, and since these are short-lived, this
suggests that recent exposure of mature lymphocytes was minimal. Frequencies of
symmetrical aberrations had increased significantly since the earlier sampling
time. Additional external radiation exposure was negligible in the plutonium
worker groups over this period. These results are consistent with the hypothesis
that hemopoietic precursor cells are being irradiated by internally deposited
plutonium with subsequent selection resulting in only cells with symmetrical
aberrations reaching the peripheral lymphocyte pool. After removal of aberrations
involving only chromosomes 7 and/or 14, which are thought to arise in vivo during
immunological development, the breakpoints involved in the aberrations were
distributed randomly among the chromosomes according to length in all three
groups of workers. Within the chromosomes the distribution between terminal,
interstitial and centromeric regions for the plutonium workers did not conform to
that expected, there being an excess in the terminal regions and a deficit in the
interstitial regions.
PMID- 9768862
TI - The effect of high-linear energy transfer ions on the electron paramagnetic
resonance signal induced in alanine.
AB - Microcrystalline samples of L-alanine irradiated with energetic high-LET cobalt
and iron ions had different EPR spectra compared to alanine samples irradiated
with low-LET photons. The differences in the shapes of the EPR spectra and their
dependence on the microwave power are related to the differences in the microwave
power saturation of the radicals induced by the various types of ionizing
radiation. The changes in the shape of the EPR spectra, which were caused by
increasing microwave power, were more pronounced in samples irradiated with low
LET radiation than with high-LET particles. This effect showed a long-term
stability and can be used to monitor radiation quality.
PMID- 9768863
TI - Autoxidation of ferrous ion complexes: a method for the generation of hydroxyl
radicals.
AB - The kinetics of the production of hydroxyl radicals during the autoxidation of
ferrous ion complexes at pH 7.4 was investigated using the fluorescent probe
coumarin-3-carboxylic acid. Polyphosphates (tri- and tetrapolyphosphate and their
adenosine derivatives), citrate, and acetic derivatives of ethyleneamine
ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid
(DTPA), triethylenetetraminehexaacetic acid (TTHA), ethylenediamine-(N,N')
diacetic acid (EDDA) and nitrilotriacetic acid (NTA) were used as iron chelators.
Production of hydroxyl radical in these chemical systems was compared with that
by radiation to determine the equivalent doses of radiation that produced equal
amounts of .OH. The amount of .OH formed during ferrous ion autoxidation is
determined by the concentration of the complex, its structure and the radical
scavenging by the chelator molecule. Production of .OH for homologous
ethylenamine acetates increases with increased complex stability: NTA < EDDA <
TTHA < EDTA < DTPA. The radiation dose equivalence for 0.1 mM complexes increased
from 5 Gy for NTA to 25 Gy for DTPA. The radiation dose equivalence for
polyphosphates was 15 Gy for tripolyphosphate and 32 Gy for tetrapolyphosphate.
The dose equivalences for adenosine phosphates are lower, 5 Gy for ATP and 10 Gy
for adenosine tetraphosphate, due to intramolecular .OH scavenging. The rate of
generation of .OH shows an inverse correlation with the charge of the ferrous ion
complex, varying from 2 cGy/s for DTPA to 1.2 Gy/s for EDTA. The data presented
indicate the usefulness of autoxidation of ferrous ion complexes for generation
of .OH in chemical systems. The ability to control the amount and the rate of
production of .OH may prove useful for examining the cytotoxic effects of .OH
generated in biological systems.
PMID- 9768864
TI - Effectiveness of protons and argon ions in initiating lipid peroxidation in low
density lipoproteins.
AB - In this study, human low-density lipoprotein (LDL) vesicles were irradiated with
73 MeV protons (LET of 1 keV/microm) and 11.4 MeV/nucleon argon ions (LET of 1.52
MeV/pm) and the effectiveness of charged particles in initiating peroxidation of
LDLs was investigated. The LDL suspension (6 g/l) was exposed to protons and to
argon ions in a dose range of 24 Gy to 2.4 kGy. Irradiations were carried out at
the synchrocyclotron at the CPO and at the UNILAC of the GSI. After irradiation
three chemical assays were used to study the progression of peroxidation of LDLs:
the formation of conjugated dienes, the formation of thiobarbituric acid-reactive
substances (TBARS) and the increase in the relative electrophoretic mobility of
the LDLs. The results were compared with those obtained after gamma irradiation.
For protons the yields of the peroxidation products were 10 times lower than
after gamma irradiation. However, for doses below 200 Gy, protons appeared to be
more effective than gamma rays in damaging the protein moiety, as deduced from
the observed increase in the relative electrophoretic mobility of the LDLs. The
irradiation with argon ions led to a negligible formation of peroxidation
products, but an increase in the relative electrophoretic mobility of the LDLs
was observed. The results are indicative of a lower yield of lipid peroxidation
after irradiation with high-LET particles. In contrast, protons and argon ions
appear to be more effective in inducing bulk protein and phospholipid damage than
gamma rays.
PMID- 9768865
TI - Effects of gamma rays on the stability and size of DNA.
AB - The effects of gamma radiation on the stability and size of mammalian DNA were
studied by using thermal transition spectrophotometry and pulsed-field and
standard agarose gel electrophoresis. The experiments were performed using
deproteinized calf thymus DNA in buffered deaerated aqueous solutions. A dual
dose response was observed: a tendency for increased helix stability at "low"
doses (0-4 Gy) accompanied by a high tendency of the DNA molecules to interact,
forming larger molecules, followed by a gradual increase of degradation and helix
instability at higher doses. The results reported here for the low-dose region
are consistent with the hypothesis of inter- and intramolecular interactions of
covalent character (crosslinking) in irradiated DNA molecules.
PMID- 9768866
TI - F values as cytogenetic fingerprints of prior exposure to different radiation
qualities: prediction, reality and future.
PMID- 9768867
TI - GABA function in mood disorders: an update and critical review.
AB - Over the past twenty years, several lines of evidence from preclinical and
clinical studies has accumulated suggesting that a GABA deficit may be involved
in mood disorders, particularly in depression, and that increasing GABAergic
neurotransmission may exert an antidepressant effect and perhaps a mood
stabilizing effect. Given that GABA has an inhibitory effect on biogenic amine
neurotransmitters such as norepinephrine and serotonin and this inhibition may be
involved in local circuits and interneurons, it has been suggested that the
hypothesis of a GABA deficit in mood disorders does not compete with but
complements the well-established hypotheses of alterations in noradrenergic and
serotonergic function in mood disorders. In this paper, we systematically
reviewed the results from preclinical and clinical studies of GABA function in
the pathophysiology of mood disorders and in the mechanism of action of mood
stabilizers, antidepressants and electroconvulsive therapy. We also discussed the
unifying theory of the neurochemistry of mood disorders, which integrates the
GABA hypothesis into the biogenic amine hypotheses, and indicated future
directions for research.
PMID- 9768868
TI - Variations and interrelation between vasopressin and plasma osmolality in
diabetic rats with insulin treatment.
AB - Although it is well known that plasma osmolality and plasma vasopressin (VP)
levels in diabetes mellitus are higher than in non-diabetic conditions (and that
these levels return to normality with insulin therapy), there are no existing
studies which examine for insulin-dependent diabetes, either the persistence of
daily rhythmic variations of VP or the relationship between this variation and
daily osmotic oscillations. We have therefore examined nycthaemeral variations in
both plasma osmolality and plasma VP in normal (C), uncontrolled (D) and
controlled insulin-dependent streptozotocin diabetic rats (DI). The uncontrolled
streptozotocin treated rats presented, a loss of VP rhythmicity, together with
higher values of VP than in both normal and controlled diabetic rats. The VP
rhythm, however, could be restored with insulin treatment. Furthermore, the
temporal VP/osmolality ratio in uncontrolled diabetic rats is higher than in
normal rats, although this ratio does not show the daily rhythmic pattern that is
present in both normal and diabetic rats treated with insulin. This may indicate
that the lack of rhythmicity in osmotic regulation is responsible for the absence
of a circadian rhythm in VP. As a result, we conclude that in uncontrolled
diabetic rats, the higher VP levels and the loss of VP circadian rhythmicity
could be due to a higher sensitivity in the osmoregulatory system, together with
an absence of circadian variation of this system. This circadian variation could
be responsible for the plasma VP rhythmicity in both normal and controlled
diabetic rats.
PMID- 9768869
TI - Mechanisms of action of endothelin-1 in rat adrenal.
AB - Displacement curves of 125I-Endothelim-1 (ET-1) binding to rat adrenal cells with
unlabeled ET-1, and the ET-1 receptor-related peptides sarafotoxin and BQ-123,
show that rat adrenal cortex possess, as its bovine counterpart, two different
receptors to ET-1 named ET-A and ET-B. Binding of ET-1 to its rat adrenal
receptors stimulates i) aldosterone production, in vivo and in vitro ii) calcium
influx, which is mediated through voltage dependent- and receptor operated-
calcium channels, iii) cholesterol uptake, iv) stimulation of Na+/K+-ATPase and
iv) diacylglycerol production. While the last effect is mediated through ET-A
receptors the others involve binding of ET-1 to ET-B receptors. Finally, ouabain
potentiates the ET-1-mediated stimulation of aldosterone production, suggesting
that the effect of the peptidic hormone on Na+/K+-ATPase could act as a negative
feedback mechanism.
PMID- 9768870
TI - Isotonic ethanol inhibits the generation of superoxide anion in neutrophils by
inducing cell expansion.
AB - The effects of ethanol on the production of oxygen-derived free radicals by
neutrophils are controversial. Osmolarity-mediated alteration of cell volume
appears to be an important mechanism for regulating neutrophil activity. We
investigated in neutrophils from healthy volunteers the effect of
isotonic/hypertonic ethanol on both chemiluminescence amplified by a Cypridina
luciferin analog in response to N-formyl-Met-Lue-Phe and cell volume measured
with a Coulter counter. Both isotonic and hypertonic ethanol significantly
decreased chemiluminescence in a dose-dependent manner. Isotonic ethanol produced
a greater magnitude of inhibition than hypertonic ethanol (P<0.01). Another
permeable molecule, urea, and hypotonic solution had the same effects on
chemiluminescence. Isotonic and hypertonic ethanol caused a prompt cell expansion
and shrinking, respectively. On the other hand, isotonic sucrose, an impermeable
molecule, was ineffective in both chemiluminescence and cell volume changes.
These data suggest that isotonic ethanol inhibits the superoxide anion production
by inducing cell expansion probably due to increased intracellular osmotic
pressure caused by rapid ethanol permeation through the plasmalemma. This
impaired neutrophil function may, in some part, contribute to the susceptibility
to infection in alcoholics.
PMID- 9768871
TI - Characterization of nuclear protein binding (AP-1, GR, and STAT) in the
genetically obese (fa/fa) Zucker rat.
AB - There is evidence to suggest that obese populations have an increased
susceptibility to various pathologic disorders. Both AP-1 and STAT nuclear
binding proteins have been suggested to play a role in certain obesity-related
diseases. The objective of our studies reported herein was to compare
constitutive binding activity of nuclear proteins (AP-1, GR, and STAT), that may
be relevant to obesity-related diseases in the obese (fa/fa) Zucker rat to lean
(Fa/?) littermates. AP-1, GR, and STAT liver nuclear protein binding activity was
analyzed using the electrophoretic mobility shift assay (EMSA). EMSA analysis of
liver nuclear protein from obese and lean Zucker rats revealed high constitutive
AP-1 binding activity in the obese animals. AP-1 binding activity in the obese
rats was not further elevated by treatment with phenobarbital, a known inducer of
AP-1 binding activity. No differences were observed in GR binding to a consensus
GRE between obese and lean animals; however, STAT binding activity to a consensus
GAS element was lower in liver tissue from obese Zucker rats. Our findings
presented herein suggest that the fa/fa Zucker rat may be a suitable obese rodent
model for studying the roles AP-1 and STAT may play in the pathologies of these
diseases.
PMID- 9768872
TI - Acute leptin action on insulin blood level and liver insulin receptor in the rat.
AB - Aim of the study was to investigate acute leptin effect on insulin blood level
and liver insulin binding in the rat. The administration of leptin induced time
and dose dependent decrease in the insulin level, which was statistically
significant in comparison to the control animals 120 min after administration of
higher dose of peptide (0.30 +/- 0.05 vs 0.14 +/- 0.01 nmol/l, respectively).
Simultaneously, we have shown the attenuation of liver sensitivity to insulin 2
hours after higher leptin dose injection. This phenomenon was caused by the
decrease of binding capacity of high affinity insulin receptor sites (HAIR),
which was statistically significant after higher leptin dose administration at
both time points (0.54 +/- 0.13 vs 0.26 +/- 0.03 and 0.71 +/- 0.12 vs 0.40 +/-
0.05 pmol/mg protein for 1 and 2 h, respectively). The present study provides
evidence that leptin, in addition to its inhibitory effect on insulin secretion,
acts as a modulator of insulin receptor, through the decrease of binding
capacity. It seems legitimate to suggest that leptin-induced decrease of insulin
receptor binding capacity may be one of several causes of insulin resistance.
PMID- 9768873
TI - HLA DR and AB surface antigens correlate with cell shape (surface area).
AB - In order to help explain some of the various phenomena associated with both
benign and malignant cells, this study was undertaken to determine if changes in
the shape of the cell could alter the recognition of the cell. Non-transformed
Human cells, HEL 299, were evaluated for their shape and surface antigens. A
direct statistical correlation was found between the two surface antigens HLA AB
and DR and the cell shape (surface area). The possible significance of this
phenomena in non transformed human cells to neoplastic proliferation is
suggested.
PMID- 9768874
TI - Depression of the hepatic cytochrome P450 by an acute inflammatory reaction:
characterization of the nature of mediators in human and rabbit serum, and in the
liver.
AB - There is increasing evidence suggesting that several mediators are involved in
the cascade of events leading to the depression of the cytochrome P450 (P450) by
an inflammatory reaction. The present study aimed to confirm the presence of
mediators in the serum (RS(INFLA)) and hepatocytes (H(INFLA)) of rabbits with an
acute inflammatory reaction, and in the serum of humans with an acute upper
respiratory tract viral infection (HS(URTVI)). The inflammatory reaction was
induced by the s.c. injection of 5 ml of turpentine. Incubation of RS(INFLA) or
HS(URTVI) with H(INFLA) depressed the P450, diminished the formation of
theophylline metabolites (3-methylxanthine, 1-methyluric acid, and 1,3
dimethyluric acid), and increased lipid peroxidation. The addition of preheated
RS(INFLA) or HS(URTVI) to H(INFLA) did not diminish the amount of P450 or
theophylline metabolites, and prevented the increase in lipid peroxidation.
Incubating the filtrate of RS(INFLA) or HS(URTVI) dialyzed through membranes with
cut-off of 10, 30, 50 and 100 kd, with H(INFLA) showed that rabbit and human
mediators have molecular weights ranging from 10 to 30 kd. Incubation of H(INFLA)
with hepatocytes from control rabbits (H(CONT)) did not decrease further the
P450. However, when RS(INFLA) was added to co-cultured H(CONT) + H(INFLA), the
depression of P450 was 37% greater (p<0.05), and the amount of theophylline
metabolites generated was around 30% (p<0.05) smaller than that observed when
H(CONT) or H(INFLA) were incubated with RS(INFLA). Based on the present results
we may speculate that human and rabbit serum mediators are proteins of molecular
weights ranging from 10 to 30 kd, and in addition, primed hepatocytes once
exposed to the serum mediators release mediators able to depress the P450 in
H(CONT).
PMID- 9768875
TI - Evidence of H3 receptor inhibition by iodoaminopotentidine in the guinea pig
ileum.
AB - Activation of histamine H3 receptors by histamine (0.1 to 10 microM), (R)alpha
methylhistamine and N(alpha)-methylhistamine (0.01 to 0.3 microM) was shown to
inhibit cholinergic nerve transmission in the guinea-pig ileum.
Iodoaminopotentidine (IAP 300 nM), a potent H2 receptor antagonist, was found to
decrease this effect but had no significant effect (P>0.05) on contractile
responses produced by exogenous acetylcholine (0.2 microM). Dimaprit (0.1 to 10
microM) an H2 receptor agonist/H3 receptor antagonist, produced no significant
effect (P>0.05) on the response to cholinergic nerve stimulation but reduced the
effect of N(alpha)-methylhistamine. Furthermore, ranitidine (10 microM) an H2
receptor antagonist did not modify the inhibitory effect of histamine. These
results suggest that IAP may inhibit H3 receptors in the ileum at similar
concentrations reported to inhibit H2 receptors in functional studies.
PMID- 9768876
TI - Slide-binding characterization and autoradiographic localization of delta opioid
receptors in rat and mouse brains with the tetrapeptide antagonist [3H]TIPP.
AB - Slide-binding and autoradiographic studies were performed on cryostat sections
from brains of adult Sprague-Dawley rats and BALB C mice to describe the binding
characteristics of the tetrapeptide [3H]TIPP, an antagonist with high specificity
and affinity for the delta opioid receptors. Steady-state binding of [3H]TIPP to
cryostat sections of brain paste was reached in 120-180 min of incubation.
Specific [3H]TIPP binding resulted in maximal numbers of binding sites (Bmax) of
15.59 and 23.91 fmol/mg protein, and dissociation constants (Kd) of 0.46 and 0.85
nM for rat and mouse brain paste sections, respectively. TIPP displayed the
highest affinity for delta opioid receptors in inhibiting specific [3H]TIPP
binding, with IC50 values of 0.82 nM and 0.14 nM in rat and mouse brain sections,
respectively. While DPDPE was also effective in displacing the specific binding
of [3H]TIPP (IC50 = 3.18 +/- 0.53 nM and 0.63 +/- 0.42 nM in rat and mouse brain
paste sections, respectively), other subclass-selective or nonopioid ligands were
much less effective, or ineffective. Autoradiographic localization of [3H]TIPP
binding revealed the characteristic distribution of delta opioid receptors in
both species. In consequence of its antagonistic nature, and of its unnatural
amino acid residue, which makes this ligand more resistant to biodegradation,
[3H]TIPP is a superior ligand for evaluation of the binding characteristics and
autoradiogaphic distribution of the delta opioid receptors.
PMID- 9768877
TI - An ex vivo evaluation of regulatory role of biogenic amines in rat seminal
vesicle after pharmacological manipulation.
AB - We studied the neural regulation of seminal vesicles (SV) by determining the
changes of intraluminal pressure of rat SV in response to an electric stimulation
of the lesser splanchnic nerve (LSN). After pharmacological manipulation with
neurotoxin, the contents of monoamines and their metabolites in SV were
estimated. In rats receiving electric stimulation of the LSN, an increase of
intraluminal pressure was obtained with a reduction of the serotonergic turnover
rate in SV. An intraperitoneal injection of DSP-4 (100 mg/kg), the noradrenergic
neurotoxin, into rats decreased the level of norepinephrine (NE) in SV
significantly but did not influence this functional response. Also, the
intraluminal pressure was lowered by an intrathecal injection of 6-OHDA (20
microg/rat) to denervate spinal monoaminergic nerves in rats although the
contents of monoamines in SV were not changed. This indicates that noradrenergic
neurotransmission appears unimportant in this regulation. The lowering of
intraluminal pressure in rats by 6-OHDA is mainly related to an attenuation of
dopaminergic neuroregulation from the decrease of turnover rate of DA. Otherwise,
an intrathecal injection of 5,7-DHT (60 microg/rat) to abolish spinal
serotonergic nerves did not influence the level of monoamines in SV but increased
the intraluminal pressure indicating an involvement of inhibitory regulation from
spinal serotonergic pathway. These results suggest that contraction by electric
stimulation of the LSN in Wistar rat SV is mainly regulated by the dopaminergic
nervous pathway and an inhibitory regulation of the serotonergic nervous pathway
from spinal cord while the noradrenergic nervous system seems unimportant for
this regulation.
PMID- 9768878
TI - Antagonism of kynurenic acid to anxiogens in mice.
AB - In a dark-light chamber in mice, kynurenic acid (KYNA, 200 mg/kg, i.p.), an
endogenous neuroactive metabolite of tryptophan, attenuated the most stable
effect of anxiogens in this model of anxiety--a decrease in the rate of leanings
out of the dark compartment --induced by caffeine, pentylenetetrazole and
yohimbine, but not by beta-phenylethylamine (PEA). KYNA by itself did not alter
behavior of mice in the chamber, in contrast to what has been observed in an
elevated plus-maze, another model of anxiety, where KYNA had an anxiolytic
pharmacological profile.
PMID- 9768879
TI - Femoral stem fixation. An engineering interpretation of the long-term outcome of
Charnley and Exeter stems.
AB - The excellent long-term results for the first-generation Charnley stem may not
apply to later versions with flanges. It seems possible that the early design
functioned as a taper-slip system, as accepted in the Exeter prosthesis.
Comparison with the requirements for the alternative composite-beam system for
the femoral component shows considerable differences that have important
implications. These include design, surface finish, cementing technique and the
interpretation of radiological signs of loosening. A distinction should be made
between the requirements for the successful use of the two different engineering
systems.
PMID- 9768880
TI - The treatment of subluxation of the hip in children over the age of four years.
AB - Subluxation of the hip presenting for the first time in a child over the age of
four years is rare. We report ten cases treated over nearly 11 years by the
senior author (JAF). We describe the surgical procedures and the results, at
maturity, of nine of the ten patients. At a mean follow-up of nearly nine years,
the clinical outcome was good in all ten children by the criteria of Ponseti.
Radiological assessment showed that three hips remained subluxed, and that four
had avascular necrosis of the physis. We advise a one-stage procedure, correcting
both the femur and acetabulum.
PMID- 9768881
TI - Residual deformity in congenital radial club hands after previous centralisation
of the wrist. Ulnar lengthening and correction by the Ilizarov method.
AB - We used the Ilizarov method in seven patients with severe congenital radial club
hands who had had previous wrist surgery, to correct residual shortening and
bowing of the ulna together with recurrent wrist deformity. The mean age at
operation was 6.5 years. The mean ulnar shortening was 5.3 cm and the mean
angular deformity 42 degrees. The mean length gained was 51% of the original
ulna. The mean healing index was 46.9 days (29.8 to 64.0). The ratio of the
length of the lengthened ulna to the normal side improved on average from 64% to
95%. The angular deformity was initially completely corrected in six out of seven
patients. The length ratio, however, decreased to 83% at the final follow-up. In
four patients, the angular deformity partially recurred. We recommend correction
of congenital radial club hand by staged procedures. The first is centralisation
and stabilisation of the wrist and the second lengthening of the ulna and
correction of the angular deformity using the Ilizarov method.
PMID- 9768882
TI - Cat-scratch disease osteomyelitis from a dog scratch.
AB - Osteomyelitis is a rare manifestation of cat-scratch disease in patients who do
not have AIDS. The clinical presentation and non-specific subacute course of the
disease make diagnosis difficult. We present a child with osteomyelitis of a
metacarpal following a dog scratch. Bartonella henselae was found to be the
aetiological agent. The bone healed after treatment with antibiotics. Increased
awareness and a comprehensive medical history are needed to identify patients
with suspected Bartonella henselae osteomyelitis.
PMID- 9768883
TI - Progressive osseous heteroplasia. Report of a family.
AB - We report a case of progressive osseous heteroplasia in a female infant who had
progressive ossification of the skin and deep connective tissues. Isolated dermal
ossification is present in her father and younger sister suggesting an autosomal
dominant mode of inheritance with variable expressivity or possible somatic
mosaicism. This report of a family with progressive osseous heteroplasia
contributes to the understanding of this uncommon genetic disorder, which must be
distinguished from fibrodysplasia ossificans progressiva and Albright's
hereditary osteodystrophy. The paucity of familial cases of progressive osseous
heteroplasia currently limits the use of a genome-wide linkage analysis, but
linkage exclusion analysis with promising candidate genes is a possibility.
PMID- 9768884
TI - Severe progressive deformities after limb lengthening in type-II fibular
hemimelia.
AB - Until recently the accepted treatment of choice for severe type-II fibular
hemimelia has been Syme's or Boyd's amputation. The alternative of distraction
lengthening using the Ilizarov technique is now available. We report three
patients (four limbs) with type-II fibular hemimelia who were treated by the
Ilizarov technique and followed up for two to six years. Severe progressive
procurvatum and valgus deformity of the tibia and valgus deformity and lateral
subluxation of the ankle were found in all four limbs. Multiple additional soft
tissue and bony surgery was necessary. In view of these problems we feel that
reappraisal of the indications for lengthening in type-II fibular hemimelia is
necessary.
PMID- 9768885
TI - Coregistration imaging of the foot. A new localisation technique.
AB - We describe a new technique, known as coregistration imaging, which superimposes
99mTc isotope bone scans on to plain radiographs. We used the technique
selectively in cases in which the nuclear medicine physician, who reported the
isotope scan, had difficulty in localising the anatomical site of the
abnormality. In the forefoot, coregistration of isotope scans did not help to
localise pathology; the scan alone gave sufficient detail. In 17 patients with
pain in the hind- and midfoot, isotope scanning identified eight sites of
abnormality in those with normal radiographs. In those with more than one
abnormality on plain radiographs the isotope scan eliminated 12 sites of
suspicion. Coregistration of the images significantly increased the certainty of
localisation of disease (p < 0.001). We recommend the selective use of
coregistration scanning as a useful technique for investigating patients with
pain in the foot and ankle.
PMID- 9768886
TI - Operative reconstruction after transverse rupture of the tendons of both peroneus
longus and brevis. Surgical reconstruction by transfer of the flexor digitorum
longus tendon.
AB - Rupture of the tendons of both peroneus longus and peroneus brevis results in
considerable disability. We have performed transfer of flexor digitorum longus
(FDL) to peroneus brevis in two patients with lateral instability of the hindfoot
due to chronic transverse tears of both tendons for which end-to-end repair was
not possible. Both patients had excellent function when reviewed after eight and
six years, respectively, with no symptoms. CT showed a normal appearance of the
FDL in both patients, but the peroneal muscles looked abnormal. Transfer of the
FDL provides a reliable solution to lateral instability of the hindfoot resulting
from loss of function of both peronei.
PMID- 9768887
TI - Subtalar arthrography in acute injuries of the calcaneofibular ligament.
AB - We treated 43 acute tears of the calcaneofibular ligament by operation in 43
patients after subtalar arthrography. There were 22 men and 21 women with a mean
age of 22.3 years (14 to 61). Anteroposterior (AP), lateral and oblique views
were obtained with the foot in 45 degrees of internal rotation and the ankle in
the neutral position. Any communication or leakage to the ankle, tendon sheaths,
subcutaneous tissue and sinus tarsi was recorded. We examined an oblique view of
the microrecess along the interosseous ligament and an AP view of the lateral
recess just under the distal end of the fibula. We also studied a control group
of 27 patients with isolated injuries of the anterior talofibular ligament
without rupture of the calcaneofibular ligament. The findings in the two groups
were significantly different when examined for leakage to the ankle (p=0.0002),
to the peroneal tendon sheaths (p=0.0347) and to the subcutaneous tissue
(p=0.0222), absence of the microrecess (p=0.0055) and presence of the lateral
recess (p=0.0012). Many ankle sprains which involve tearing of the
calcaneofibular ligament are accompanied by injuries of the subtalar joint.
Combined injuries of the anterior talofibular ligament and calcaneofibular
ligament, and isolated injury of the anterior talofibular ligament should be
differentiated.
PMID- 9768888
TI - Second fracture of the distal humerus after varus malunion of a supracondylar
fracture in children.
AB - Nine children sustained a second fracture of the distal humerus after union of an
ipsilateral supracondylar fracture which had healed with cubitus varus. There
were eight boys and one girl with a mean age of five years (1 to 8) at the time
of the second fracture which occurred at a mean of 1.5 years after the first. In
all patients, the second fracture was an epiphyseal injury of the distal humerus,
either associated with a fracture of the lateral metaphysis below the site of the
previous supracondylar fracture, or a fracture-separation of the entire distal
humeral epiphysis. This suggests that the physis and epiphysis tend to be more
subject to injury than the metaphysis of the distal humerus in children who have
had a previous supracondylar fracture with varus malunion.
PMID- 9768889
TI - Open reduction, internal fixation and fibular autografting for neglected fracture
of the femoral neck.
AB - Neglected fractures of the femoral neck, common in young adults in underdeveloped
countries, may be complicated by nonunion or avascular necrosis (AVN). We treated
52 cases by open reduction, fixation by compression screw and a free fibular
graft. The mean delay between injury and operation was 5.1 months. Of 40
fractures assessed at a mean of 58.8 months (24 to 153), 38 were found to be
united and two, owing to surgical errors, were not. Seven of eight heads which
were avascular before operation revascularised without collapse, while seven
others developed AVN after the procedure. At the last follow-up considerable
collapse was apparent in five femoral heads, and 11 hips had developed coxa vara.
The fibular graft had fractured in four cases. The hip had been penetrated by the
screw in six cases and by the graft in three. Hip function was excellent in seven
patients, good in 21 and fair in seven. Five patients had poor results.
Incorporation of the fibular graft was seen after four years: in many cases the
graft had been almost completely resorbed. We recommend this procedure for the
treatment of neglected fractures of the neck of the femur in young adults to
reduce resorption of the neck, AVN and nonunion.
PMID- 9768890
TI - Post-traumatic contracture of the elbow. Operative release using a lateral
collateral ligament sparing approach.
AB - We performed a lateral approach for the release of post-traumatic stiffness of
the elbow in 22 patients using a modified technique designed to spare the lateral
ligaments. They were reviewed after a mean interval of 26 months. The total
humeroulnar joint movement had increased from a mean of 74 degrees to 129 degrees
and forearm rotation from a mean of 135 degrees to 159 degrees. Both pain and
function in the elbow had improved significantly. This modified lateral approach
allows release of post-traumatic contracture without disruption of the lateral
collateral ligament or the origins of the extensor tendon at the lateral
epicondyle of the humerus. The advantages include a simplified surgical
procedure, less operative morbidity, and unrestricted rehabilitation.
PMID- 9768891
TI - Open acromioplasty does not prevent the progression of an impingement syndrome to
a tear. Nine-year follow-up of 96 cases.
AB - We performed open acromioplasty for intractable impingement syndrome on 96
shoulders (93 patients) with an intact rotator cuff. All the shoulders were
examined by ultrasound after a mean interval of nine years. Those showing
pathological findings, a poor or fair subjective result, or deterioration of the
primary excellent outcome had MRI and/or arthrography. The mean Constant score
for the affected shoulders was 70 points and that for 48 non-involved, symptom
free shoulders, 84 points. The subjective outcome was excellent in 45, good in
24, fair in 18 and poor in 9 shoulders. Complete tears were found in 12 shoulders
and partial tears in seven. A total of 14 shoulders was symptom-free after
acromioplasty, but after an average of five years became painful again and showed
deterioration. Of these, six had complete tears and four partial tears of the
cuff. The tear rate was 4% in shoulders initially judged to be excellent, 25% in
good, 33% in fair and 55% in poor shoulders. The tear rate was 71% in shoulders
which subsequently deteriorated. The incidence was higher in men (25%) than in
women (11%). We conclude that a tear of the rotator cuff may appear after
acromioplasty, although there was no evidence of a tear at the time of operation.
This is usually the reason for deterioration in a shoulder with an initially good
operative outcome.
PMID- 9768892
TI - Osteotomy of the radius and ulna for the Madelung deformity.
AB - The Madelung deformity can result in pain and decreased function of the wrist and
hand. None of the surgical techniques available has been shown consistently to
improve grip strength, range of movement or relieve pain. In this prospective
study we have treated 18 patients with the Madelung deformity (25 wrists) by
wedge subtraction osteotomy of the radius and shortening of the ulna. Our results
show statistically significant improvement in grip strength and range of movement
of the wrist and forearm. Pain improved in 80% of the patients and 88% were
satisfied with the appearance. One patient had a wound infection and another
developed reflex sympathetic dystrophy. Two had some recurrence due to continued
growth of the ulna and it is recommended that the procedure be delayed until
skeletal maturity, or else combined with epiphysiodesis of the ulna.
PMID- 9768893
TI - Ipsilateral recurrent lumbar disc herniation. A prospective, controlled study.
AB - We analysed prospectively 26 patients who had revision operations for ipsilateral
recurrent radicular pain after a period of pain relief of more than six months
following primary discectomy. They were assessed before the initial operation,
between the two procedures and at a minimum of two years after reoperation. MRI
was performed before primary discectomy and reoperation. Fifty consecutive
patients who had a disc excision during the study period but did not have
recurrent radicular pain, were analysed as a control group. Of the study group
42% related the onset of recurrent radicular pain to an isolated injury or a
precipitating event, but none of the control group did so (p < 0.001). T2
weighted MRI performed before primary discectomy showed that patients in the
study group had significantly more severe disc degeneration compared with the
control group (p=0.02). Intraoperative findings revealed recurrent disc
herniation in 24 patients and bulging of the disc in two, one of whom also had
lateral stenosis. Epidural scarring was found to be abundant, intraoperatively
and on MRI, in eight and in nine patients, respectively. At the last follow-up,
the clinical outcome was satisfactory in 85% of patients in the study group and
in 88% of the control group (p > 0.05). Work or daily activities had been resumed
at the same level as before the onset of symptoms by 81% of the patients in the
study group and 84% of the control group. No correlation was found between the
amount of epidural fibrosis, as seen intraoperatively and on MRI, and the result
of surgery. The recurrence of radicular pain caused no significant changes in the
psychological profile compared with the assessment before the primary discectomy.
PMID- 9768894
TI - Changes in the disc space after fractures of the thoracolumbar spine.
AB - We have studied the intervertebral discs adjacent to fractured vertebral bodies
using MRI in 63 patients at a minimum of 18 months after injury. There were 75
thoracolumbar fractures of which 26 were treated conservatively and 37 by
posterior reduction and fusion with an AO internal fixator. We identified six
different types of disc using criteria based on the morphology and the intensity
of the MRI signal. The inter- and intraobserver variability of this system was
good. Most of the discs showed predominantly morphological changes with no
variation in signal intensity. Some disc types were associated with progressive
kyphosis in patients treated conservatively. In those managed by operation,
recurrent kyphosis appeared to result from creeping of the disc in the central
depression of the bony endplate rather than from disc degeneration. Changes in
the disc space after posterior fixation should not be seen as a form of chronic
instability but as a redistribution of the disc tissue in the changed morphology
of the space after fractures of the endplate.
PMID- 9768895
TI - Fracture-dislocation of the fifth lumbar vertebra. A new classification.
AB - We have studied fracture-dislocation of the fifth lumbar vertebra in seven
patients and reviewed 50 previously reported cases. Based on this information, we
have classified the injury into five types: type 1, unilateral lumbosacral facet
dislocation with or without facet fracture; type 2, bilateral lumbosacral facet
dislocation with or without facet fracture; type 3, unilateral lumbosacral facet
dislocation and contralateral lumbosacral facet fracture; type 4, dislocation of
the body of L5 with bilateral fracture of the pars interarticularis; and type 5,
dislocation of the body of L5 with fracture of the body and/or pedicle, with or
without injury of the lamina and/or facet. Conservative treatment of fracture
dislocation of L5 is generally not effective because the lesion is fundamentally
unstable. Planning of the operation should be made on the basis of the various
types of injury.
PMID- 9768896
TI - Radiculopathy after laminectomy for cervical compression myelopathy.
AB - Postoperative radiculopathy is a complication of posterior cervical decompression
associated with tethering of the nerve root. We reviewed retrospectively 287
consecutive patients with cervical compression myelopathy who had been treated by
multilevel cervical laminectomy and identified 37 (12.9%) with postoperative
radiculopathy. There were 27 men and ten women with a mean age of 56 years at the
time of operation. The diagnosis was either cervical spondylosis (25 patients) or
ossification of the posterior longitudinal ligament (12 patients). Radiculopathy
was observed from four hours to six days after surgery. The most frequent pattern
of paralysis was involvement of the C5 and C6 roots of the motor-dominant type.
The mean time for recovery was 5.4 months (two weeks to three years). The results
at follow-up showed that the rate of motor recovery was negatively related to the
duration of complete recovery of postoperative radiculopathy (gamma=-0.832, p <
0.01) and that patients with spondylotic myelopathy had a significantly better
rate of clinical recovery than those with ossification of the posterior
longitudinal ligament (t=2.960, p < 0.01). Postoperative radiculopathy may be
prevented by carrying out an anterior decompression in conjunction with spinal
fusion, which will achieve stabilisation and directly remove compression of the
cord at multiple levels.
PMID- 9768897
TI - Total knee arthroplasty with the PFC system. Results at a minimum of ten years
and survivorship analysis.
AB - A consecutive series of 235 total knee arthroplasties using the PFC system was
followed prospectively for at least ten years in 186 patients. The operation was
for osteoarthritis in 150 knees, for rheumatoid arthritis in 83, and for Paget's
disease and femoral osteonecrosis in one knee each. At the latest review 56
patients had died, five were too ill to assess and three could not be traced. The
PFC knee replacement utilised was a non-conforming posterior-cruciate-retaining
prosthesis with a polyethylene insert which is flat in the sagittal plane. The
patella was resurfaced using a metal-backed component in 170 cases, but later in
the series we used an all-polyethylene component in 22 knees; 43 patellae were
not resurfaced. The survival without need for reoperation for any reason was 90%
at ten years. Nineteen revisions were component-related due to failure of nine
metal-backed patellae, nine polyethylene inserts, and one unresurfaced patella;
two reoperations were for synovectomy (one for recurrent haemarthrosis and one
for recurrent rheumatoid synovitis) and three were for metastatic joint
infection. There were no revisions for aseptic loosening of femoral or tibial
components, or the all-polyethylene patellar replacement. The PFC system provides
good and predictable results in tricompartmental arthritis of the knee. Loosening
appeared to be negligible, but there were wear-related problems in 8%. The change
from a metal-backed patella and an increase in the contact area of the tibial
insert should provide further improvement by minimising wear.
PMID- 9768898
TI - Replacement arthroplasty of the valgus knee. A modified lateral capsular approach
with repositioning of vastus lateralis.
AB - Total knee arthroplasty (TKR) using a medial capsular approach gives worse
results in arthritic knees with valgus deformity than in those in varus, usually
because of swelling, poor wound healing and stiffness, instability, recurrent
valgus deformity and poor patellar tracking. A technique for replacement TKR of
valgus knees using a lateral capsular approach was described several years ago,
but was not routinely adopted because of the difficulties with and complexity of
the procedure which included deliberate elevation of the tibial tubercle. In
order to avoid this we have modified and simplified the procedure. Our
preliminary results suggest that this lateral approach is safe and may give a
better outcome than that through the medial capsule for the replacement of valgus
knees.
PMID- 9768899
TI - Unicompartmental or total knee replacement? Five-year results of a prospective,
randomised trial of 102 osteoarthritic knees with unicompartmental arthritis.
AB - We randomised 102 knees suitable for a unicompartmental replacement to receive
either a unicompartmental (UKR) or total knee replacement (TKR) after arthrotomy.
Both groups were well matched with a predominance of females and a mean age of 69
years. Patients in the UKR group showed less perioperative morbidity, but
regained knee movement more rapidly and were discharged from hospital sooner. At
five years, two UKRs and one TKR had been revised; another TKR was radiologically
loose. All other knees appeared to be clinically and radiologically sound. Pain
relief was good in both groups but the number of knees able to flex > or =120
degrees was significantly higher in the UKR group (p < 0.001) and there were more
excellent results in this group. Our findings have shown that UKR gives better
results than TKR and that this superiority is maintained for at least five years.
PMID- 9768900
TI - Acute compartment syndrome of the thigh after joint replacement with
anticoagulation.
AB - We describe three patients with a compartment syndrome of the thigh, two after
total hip replacement and one after total knee replacement. Two of the patients
were fully anticoagulated. A compartment syndrome of the thigh is a rare, but
important complication of joint replacement surgery if patients are receiving
anticoagulants. Close observation is needed and when indicated monitoring of the
intracompartmental pressure should be done. Early recognition of the signs and
symptoms of an acute compartment syndrome and knowledge of the anatomy of the
compartments of the thigh will help in the diagnosis and treatment of this
potentially devastating complication.
PMID- 9768901
TI - A ported, proximally-cemented femoral stem for total hip arthroplasty.
Development and clinical application.
AB - We describe the development and early clinical application of a ported,
proximally-cemented titanium stem for cemented total hip arthroplasty. PMMA bone
cement is delivered to the proximal femur under pressure after the stem has been
positioned within the femoral canal. A mid-stem cement occluder contains the
cement to the proximal stem only. A tapered body is incorporated in the design of
the stem to reduce the structural stiffness and hence the degree of stress
shielding within the reconstructed joint. We performed preclinical studies to
measure the reduction in porosity and the pressurisation achieved. The porosity,
as measured by the void percentage within the cured cement mantle, was reduced by
more than 50% and there was an almost threefold increase in the mean pressure.
Mechanical testing of the stem, using a three-point bend test, showed that the
addition of cement injection ports on the anterior and posterior sides of the
body of the proximal stem did not reduce its strength. Finite-element analysis
indicated that, compared with a fully-cemented conventional stem, there was no
change in the stresses within the cement mantle. In a series of 40 proximally
cemented stems followed for up to six years (mean 51 months) the mean Harris hip
score was 91, and 85% of patients had good or excellent results. There was
excellent pain relief, an increased level of activity and good patient
satisfaction. One mechanical failure of the stem required revision at three years
after implantation. The early results indicate that the clinical performance was
equal to that achieved with other modern cemented stems. Radiological evaluation
showed excellent results with no evidence of stress shielding. Further follow-up
will determine if long-term stress shielding is reduced and if revision is made
easier by the absence of a distal cement mantle.
PMID- 9768902
TI - Incisional cellulitis after total hip replacement.
AB - We report 16 cases of erythematous eruption on the skin within the flaps of the
surgical incision after primary total hip replacement over an eight-year period.
The symptoms began within nine months of operation in 13 hips, and two to three
years after in three. Four patients had recurrent episodes. All were treated with
antibiotics (15 intravenous, one oral) with complete resolution of the eruption
within one to six days. The mean follow-up after the last episode of cellulitis
was 27 months (14 to 76). There were no cases of periprosthetic sepsis or other
sequelae.
PMID- 9768903
TI - Changes in the expression of Fas, osteonectin and osteocalcin with age in the
rabbit growth plate.
AB - Chondrocytes of the growth plate are generally assumed to undergo apoptosis, but
the mechanisms which induce this cell death are not known. The Fas receptor is a
mediator of the apoptotic signal in some systems. We studied its expression in
situ in growth plates of rabbits aged from five to 20 weeks. In addition, we
investigated the immunolocalisation in the growth plates of the bone proteins,
osteonectin and osteocalcin, and the changes in their expression with age. The
Fas-positive chondrocytes were found mostly in the hypertrophic zone, as were the
osteonectin-positive and osteocalcin-positive cells. The percentage of Fas
positive cells increased with age whereas little change was found in the number
of osteonectin-positive and osteocalcin-positive chondrocytes. Many of the Fas
positive chondrocytes were also TUNEL-positive. This strongly suggests that
apoptosis in the growth plate is mediated through the Fas system. Double
immunostaining for osteocalcin and Fas showed that not all hypertrophic
chondrocytes were of the same cell type. Some chondrocytes stained for
osteocalcin only, others for Fas only, while some were positive for both.
PMID- 9768904
TI - Anti-inflammatory properties of titanium in the joint environment. An
experimental study in rats.
AB - Little is known about the tissue reactions to various implant materials which
coincide with an inflammatory reaction. We used the avridine arthritis rat model
to evaluate the tissue response in the synovial, interstitial and subcutaneous
tissues after implant insertion. Quantitative immunohistochemistry showed that
normal joint synovial tissue is dominated by ED2-positive resident macrophages.
Polyethylene implants induced a much stronger foreign-body reaction than titanium
implants, as measured by the number of interfacial ED1-positive macrophages. The
tissue response to titanium and polyethylene was also vastly different in
arthritic synovial tissue compared with control tissue. It is likely that these
biomaterials interact differently with inflammatory cells or intermediary
compounds. It may be that arthritic synovial tissue produces reactive oxygen
intermediates (free radicals) with which titanium has a unique anti-inflammatory
interaction in vitro.
PMID- 9768905
TI - Quantification of third-body damage and its effect on UHMWPE wear with different
types of femoral head.
AB - We examined stainless-steel, cobalt-chrome, titanium and alumina and zirconia
ceramic femoral heads retrieved at revision surgery. All the heads had
articulated against ultra-high-molecular-weight-polyethylene (UHMWPE) acetabular
cups. We studied the simulation of third-body damage and the wear of UHMWPE
against the various materials used for the heads. The surfaces of the retrieved
heads were analysed using a two-dimensional contacting profilometer. Third-body
damage was characterised by the mean height of the scratches above the mean line
(Rpm). The alumina ceramic and zirconia ceramic retrieved heads were found to
have significantly less damage. In laboratory studies the ceramics were also more
resistant to simulated third-body damage than the metal alloys. We studied the
wear of UHMWPE against the damaged counterfaces in simple configuration tests.
The damaged ceramics produced less polyethylene wear than the damaged metal
counterfaces. The wear factor of UHMWPE against the damaged materials was
dependent on the amount of damage to the counterface (Rp). Our study has shown
the benefit of using the harder and more damage-resistant ceramic materials for
femoral heads.
PMID- 9768906
TI - In vitro measurement of patellofemoral force after three types of knee
replacement.
AB - Using a new, non-invasive method, we measured the patellofemoral force (PFF) in
cadaver knees mounted in a rig to simulate weight-bearing. The PFF was measured
from 20 degrees to 120 degrees of flexion before and after implanting three
designs of knee prosthesis. Medial unicompartmental arthroplasty with a meniscal
bearing prosthesis and with retention of both cruciate ligaments caused no
significant change in the PFF. After arthroplasty with a posterior-cruciate
retaining prosthesis and division of the anterior cruciate ligament, the PFF
decreased in extension and increased by 20% in flexion. Implantation of a
posterior stabilised prosthesis and division of both cruciate ligaments produced
a decrease in the PFF in extension but maintained normal load in flexion. There
was a direct relationship between the PFF and the angle made with the patellar
tendon and the long axis of the tibia. The abnormalities of the patellar tendon
angle which resulted from implantation of the two total prostheses explain the
observed changes in the PFF and show how the mechanics of the patellofemoral
joint depend upon the kinematics of the tibiofemoral articulation.
PMID- 9768907
TI - Dupuytren's disease and frozen shoulder induced by treatment with a matrix
metalloproteinase inhibitor.
AB - In a series of 12 patients with inoperable gastric carcinoma who had treatment
with a synthetic matrix metalloproteinase inhibitor (Marimastat) for more than
one month, six developed a frozen shoulder or a condition resembling Dupuytren's
disease. This suggests that the matrix metalloproteinases, a family of naturally
occurring proteinases, may be involved in the pathogenesis of these two
conditions. Our observation opens avenues for further research which could lead
to local or systemic therapeutic interventions for frozen shoulder and
Dupuytren's disease.
PMID- 9768908
TI - C-reactive protein level after total hip and total knee replacement.
AB - Our study has determined the response of C-reactive protein (CRP) after total
knee replacement (TKR). The peak level occurs on the second postoperative day and
is significantly greater than that after total hip replacement (THR). The level
returns to normal at similar times after both procedures. The physiological
response to TKR as measured by the area under the CRP/time curve is significantly
greater than that after THR. Rising CRP levels after the third postoperative day
may indicate a complication of surgery such as infection.
PMID- 9768909
TI - Bone-resorbing cytokines in serum of patients with aseptic loosening of hip
prostheses.
AB - Our aim was to determine if the serum levels of bone-resorbing cytokines (IL
1beta, TNF-alpha, IL-6, GM-CSF) are altered in patients with aseptic loosening of
a total hip prosthesis, and if such levels are influenced by the type of implant.
We determined cytokine levels in sera from 35 patients before revision for failed
total hip arthroplasty and compared them with those in 25 healthy donors. We also
assessed the soluble receptor of interleukin-2 (sIL-2r) in serum as an indication
of a specific immune reaction against the implant. Our findings showed that the
sIL-2r and TNF-alpha serum level did not change. The IL-6 level was not
significantly altered, but was higher in patients with TiAIV prostheses than in
those with a CrCoMo implant and in patients with cemented prostheses. The IL
1beta level was found to be higher in those with a TiAIV cemented prosthesis than
in the control group (p=0.0001) and other groups of patients (p=0.003 v
uncemented TiAIV, p=0.01 v cemented CrCoMo, p=0.001 v uncemented CrCoMo). The GM
CSF level significantly increased in patients compared with healthy subjects
(p=0.008), and it was higher in those with cemented than with uncemented implants
(p=0.01). Only patients with cementless CrCoMo prostheses had levels of GM-CSF
similar to those of the control group. The highest GM-CSF concentrations were
observed in patients treated with non-steroidal anti-inflammatory drugs (NSAIDs)
in the last months before revision (p=0.04). In addition, when massive osteolysis
was observed, the level of GM-CSF tended to decrease to that of the control
group.
PMID- 9768910
TI - Autologous perichondral tissue for meniscal replacement.
AB - Our aim was to examine the potential of autologous perichondral tissue to form a
meniscal replacement. In 18 mature sheep we performed a complete medial
meniscectomy. The animals were then divided into two groups: 12 had a meniscal
replacement using strips of autologous perichondral tissue explanted from the
lower rib (group G) and six (group C) served as a control group without a
meniscal replacement. In all animals restriction from weight-bearing was achieved
by means of transection and partial resection of tendo Achillis. Six animals
(four from group G and two from group C) were each killed at 3, 6 and 12 months.
The grafts and the underlying articular cartilage were removed and studied by
gross macroscopic examination, light microscopy, SEM, polarised light
examination, and by biomechanical tests. In all the transplanted animals a new
perichondral meniscus developed. After three months the transplants resembled
normal menisci in size and thickness, while in the control animals only small
rims of spontaneously grown tissue were seen. Microscopically, the perichondral
menisci showed a normal orientation of collagen fibres and normal cellular
characteristics, but in the central region, areas of calcification disturbed the
regular tissue differentiation. Healing tissue in control animals lacked the
normal fibre orientation and cellularity. SEM of perichondral menisci showed
surface characteristics similar to those of normal sheep menisci without fissures
and lacerations; the control specimens had these defects. The femoral and tibial
cartilage in contact with the new menisci had normal surface characteristics
apart from one animal with slight surface irregularities. Control animals showed
superficial lesions after three months which increased at six to 12 months
postoperatively. Microangiography of the newly grown tissue demonstrated a less
intense vascularisation after three months when compared with normal menisci. The
failure stress and tensile modulus of perichondral menisci were significantly
lower than those of normal contralateral menisci, and spontaneously regenerated
tissue in meniscectomised animals had even lower values. There were no
significant differences in values between newly grown perichondral menisci and
spontaneously grown tissue.
PMID- 9768911
TI - Effects of particulate debris on macrophage-dependent fibroblast stimulation in
coculture.
AB - The interactions between the different cell types in periprosthetic tissue are
still unclear. We used a non-contact coculture model to investigate the effects
of polymethylmethacrylate (PMMA) particles and human macrophage-derived soluble
mediators on fibroblast activation. Macrophages were either exposed or not
exposed to phagocytosable PMMA particles, but fibroblasts were not. Increasing
numbers of macrophages were tested in cocultures in which the fibroblast cell
number was held constant and cultures of macrophages alone were used for
comparison of cytokine release. We used the release of interleukin-1 beta (IL
1beta), interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-alpha), lysosomal
enzyme and metalloproteinase activity to assess the cultivation of macrophages
and fibroblasts. In cocultures, IL-6 release was increased 100-fold for both
unchallenged and particle-challenged cultures when compared with macrophage
cultures alone. Furthermore, particle-challenged cocultures had threefold higher
IL-6 levels than unchallenged cocultures. Release of TNF-alpha was similar in
cocultures and in macrophage cultures. IL-1beta release in cocultures was
independent of the macrophage-fibroblast ratio. Lysosomal enzyme activity and
metalloproteinase activity were increased in cocultures. Our data show that
macrophages and fibroblasts in coculture significantly increase the release of IL
6 and to a less degree other inflammatory mediators; particle exposure
accentuates this effect. This suggests that macrophage accumulation in fibrous
tissue may lead to elevated IL-6 levels that are much higher than those caused by
particle activation of macrophages alone. This macrophage-fibroblast interaction
represents a novel concept for the initiation and maintenance of the inflammatory
process in periprosthetic membranes.
PMID- 9768912
TI - Superolateral wear of the acetabulum.
PMID- 9768913
TI - The anatomy of acute scaphoid fractures.
PMID- 9768914
TI - Effect of particulate cobalt, chromium and cobalt-chromium alloy on human
osteoblast-like cells in vitro.
PMID- 9768915
TI - Diagnostic value of intra-articular anaesthetic in primary osteoarthritis of the
hip.
PMID- 9768916
TI - Thoracic surgeons and tobacco: past failures and present opportunity.
AB - Thoracic surgeons play a major role in the treatment of tobacco-caused disease.
Historically, thoracic surgeons have been committed investigators of tobacco
caused disease and activists for tobacco control reform. This editorial reviews
and comments on the current activity of American thoracic surgeons, thoracic
surgical societies, and journals in these areas. Thoracic surgeons have been
remiss in their individual and collective public health responsibility to inform
the public and advocate tobacco control reforms. We must commit to a more
energetic effort.
PMID- 9768917
TI - Complementary use of antegrade and retrograde cardioplegia.
PMID- 9768918
TI - Aortic valve replacement for octogenarians: are small valves bad?
AB - BACKGROUND: As the population ages, more octogenarians become candidates for
aortic valve replacement. Many octogenarians, particularly women, have a small
aortic annulus and there is uncertainty as to the optimal management of this
situation in that age group. METHOD: To examine this issue, we reviewed 248
octogenarians (mean age, 82.6 +/- 2.3 years; 58% men) who underwent primary
isolated aortic valve replacement (n = 99), or aortic valve replacement and
coronary revascularization (n = 149), between 1980 and 1995. Nineteen-millimeter
valves were used in 26% of the patients. RESULTS: In-hospital mortality was 8.9%,
5% for aortic valve replacement alone and 11.4% for aortic valve replacement and
coronary revascularization. It was 12.5% for the 19-mm size valves compared with
7.7% for the bigger size valves (p = 0.24). Follow-up (mean interval, 4.4 years)
demonstrated survival for all patients of 85%, 60%, and 30% and survival free
from cardiovascular events of 80%, 45%, and 21% at 1, 5, and 10 postoperative
years, respectively. Multivariate analysis identified triple-vessel disease and
preoperative congestive heart failure as associated with increased risk for both
in-hospital and late mortality (p < 0.05). Valve size did not influence late
survival or event-free survival regardless of body surface area. CONCLUSIONS: The
use of small aortic valve prostheses in octogenarians does not adversely affect
the incidence of early or late mortality or cardiac events.
PMID- 9768919
TI - Mitral valve replacement: randomized trial of St. Jude and Medtronic Hall
prostheses.
AB - BACKGROUND: This study was designed to better define the merits of the bileaflet
and tilting-disc valves. METHODS: We prospectively randomized 156 patients (mean
age, 59 years) to receive either the St. Jude (n = 80) or the Medtronic Hall (n =
76) mitral valve prosthesis between September 1986 and December 1997. The two
groups were not significantly different with respect to preoperative New York
Heart Association class, left ventricular ejection fraction, incidence of mitral
stenosis or insufficiency, extent of coronary artery disease, completeness of
revascularization, or cross-clamp or bypass time. RESULTS: The operative
mortality (11.2% versus 13.1%, St. Jude versus Medtronic Hall, respectively) and
late mortality (27% versus 22%, St. Jude versus Medtronic Hall, respectively)
were not significantly different. Follow-up was complete in all hospital
survivors with a mean of 60.7 months (range, 1 to 133 months). The analysis of 10
year actuarial survival and freedom from valve-related events demonstrated no
significant differences between the cohorts. Freedom from reoperation was higher
in the St. Jude group (p < 0.01). Comparisons of patient functional status and
echocardiographic hemodynamic parameters obtained at the time of follow-up
demonstrated no significant differences between the two prostheses. CONCLUSIONS:
This study suggests that there is no difference between the St. Jude and
Medtronic Hall prostheses with respect to late clinical performance or
hemodynamic results and therefore does not support the preferential selection of
either prosthesis.
PMID- 9768920
TI - Bilateral radial artery grafts in coronary reconstruction: technique and early
results in 261 patients.
AB - BACKGROUND: To achieve arterial myocardial revascularization we have
progressively used more single and bilateral internal thoracic artery and radial
artery (RA) grafts. We evaluated our early experience with bilateral radial
artery to coronary grafts. METHODS: As part of their coronary reconstruction, 261
patients had 522 bilateral RA grafts from March 1995 to June 1997. Mean age was
61.1 years. There were 70 (27%) patients with non-insulin-dependent diabetes and
13 (5%) with insulin-dependent diabetes. Unstable angina was seen in 54 (21%)
patients. Left ventricular ejection fraction less than 50% was noted in 74
(28.4%) patients. Coronary revascularization was completed with additional single
internal thoracic artery in 229 patients (88%), bilateral internal thoracic
artery in 25 patients (9.6%), and vein grafts in 13 patients (5%). Intraluminal
1% papaverine in blood was used. There were 3.6 +/- 0.7 distal anastomoses per
patient, with a total of 939, 921 (98%) with arterial conduits and 18 with vein
grafts. Five hundred ninety-four (63%) of the anastomoses were with RAs. Of the
522 RA grafts 72 (13.8%) were used sequentially. The RA was most frequently
placed to the circumflex marginals (261 patients, 100%) and posterior descending
(169 patients, 65%). Proximal RA anastomosis was directly to the aorta in 472
patients, the internal thoracic artery in 42, or another RA in 8. All anastomoses
were constructed during a single cross-clamp period (mean, 74.2 +/- 26.6
minutes). RESULTS: Operative mortality was 2 patients (0.8%). Complications
included stroke in 2 patients (0.8%), deep internal infection in 2 (0.8%),
reoperation for hemorrhage in 1 (0.4%), and myocardial infarction in 2 (0.8%).
Mean peak creatine kinase-MB was 13.2 +/- 11.6 IU/L. There were no forearm
infections or hand ischemia, but there were 4 (1.6%) hematomas, 1 requiring
drainage. Angiography was done on 16 patients with RA grafts, a mean of 4.2
months postoperatively. Twenty of 22 distal anastomoses were patent (91%), and
there was 1 occlusion and 1 string sign. CONCLUSIONS: Bilateral RA to coronary
grafting extends the scope of arterial myocardial revascularization, and is safe.
Late angiographic results are required.
PMID- 9768921
TI - Left ventricular functional improvement after transmyocardial laser
revascularization.
AB - BACKGROUND: Transmyocardial laser revascularization has been used to treat
patients with end-stage coronary artery disease that is not amenable to standard
revascularization. Although there is evidence of angina relief and quality of
life enhancement, there is little information concerning improvement in
myocardial contractility. The purpose of this study was to determine whether
transmyocardial laser revascularization improves myocardial function in
chronically ischemic myocardium. METHODS: In a model of chronic ischemia by
Ameroid occlusion of the circumflex artery, domestic pigs (n = 8) were treated
with transmyocardial laser revascularization. Before laser treatment, segmental
contraction was assessed at rest and with dobutamine stress echocardiography.
Myocardium subtended by the occlusion was compared with that remote from the
occlusion. Six weeks after transmyocardial laser revascularization, the animals
were restudied at rest and with stress, and then sacrificed. Sham-treated control
animals (n = 4) underwent the same procedures but were not treated with
transmyocardial laser revascularization. Control animals did not demonstrate
significant recovery of function. RESULTS: Transmyocardial laser
revascularization improved resting function in chronically ischemic myocardium by
100%. CONCLUSIONS: Transmyocardial laser revascularization significantly improves
the function of chronically ischemic myocardium. These data may help explain the
mechanisms by which transmyocardial laser revascularization is clinically
effective.
PMID- 9768922
TI - Preconditioning during simulated MIDCABG attenuates blood flow defects and
neutrophil accumulation.
AB - BACKGROUND: Ischemic preconditioning (IP) may be cardioprotective in minimally
invasive direct coronary artery bypass where cardioplegia is not used. This study
tested the hypothesis that IP of the area at risk (AAR) would attenuate
postischemic injury from transient coronary artery occlusion. METHODS: In 19
anesthetized dogs, the left anterior descending coronary artery was occluded for
30 minutes (simulating coronary occlusion during anastomosis) followed by 3 hours
of reperfusion. In 10 dogs, occlusion was preceded by 5 minutes of occlusion and
5 minutes of reperfusion (IP), whereas 9 other dogs had no IP (control, C).
RESULTS: Thirty minutes of left anterior descending occlusion caused comparable
dyskinesis (systolic shortening, sonomicrometry) in the AAR in C (baseline, 29%
+/- 3% to 3% +/- 2%) and in IP (baseline, 29% +/- 2% to -0.3% +/- 2%). After 3
hours of reperfusion, systolic shortening was significantly depressed in C (20%
+/- 4%), and was not significantly improved by IP (24% +/- 3%, p = 0.8 versus C).
Postischemic diastolic stiffness in the AAR was not altered by IP versus C (0.60
+/- 0.12 versus 0.41 +/- 0.13). Plasma creatine kinase activity was similar
between C and IP at the end of reperfusion (20 +/- 11 versus 16 +/- 5 U/g).
Postischemic AAR blood flow (in milliliters per minute per gram of tissue) at 180
minutes of reperfusion decreased by 56% versus baseline in C (from 1.04 +/- 0.4
to 0.46 +/- 0.12; p < 0.05) compared with no change in IP (from 0.74 +/- 0.23 to
0.60 +/- 0.10), but there was no significant group difference at this time.
Myeloperoxidase activity as an index of neutrophil accumulation in AAR was
decreased in IP versus C (0.4 +/- 0.09 versus 0.7 +/- 0.04 U/microg tissue).
CONCLUSIONS: Ischemic preconditioning does not decrease postischemic wall motion
and only modestly increases postischemic blood flow abnormalities in the AAR, but
does significantly inhibit neutrophil accumulation.
PMID- 9768923
TI - Inhibition of inducible nitric oxide synthase after myocardial ischemia increases
coronary flow.
AB - BACKGROUND: The role of nitric oxide synthase in myocardial ischemia-reperfusion
injury is complex. Our hypothesis was that inducible nitric oxide synthase has a
role in the regulation of coronary flow after ischemia. METHODS: Four groups of
isolated blood-perfused rabbit hearts underwent sequential periods of perfusion,
ischemia, and reperfusion (20, 30, and 20 minutes). Two groups underwent 40
minutes of perfusion. Ischemic groups received saline vehicle, N omega-nitro-L
arginine methyl ester (L-NAME) or the highly specific inducible nitric oxide
synthase inhibitor 1400W in low or high doses during reperfusion. Two nonischemic
groups were treated with saline vehicle or 1400W during the last 20 minutes of
perfusion. Left ventricular developed pressure and coronary flow were measured
after each perfusion period. Ventricular levels of myeloperoxidase and cyclic
guanosine monophosphate were measured at the end of the second perfusion period.
RESULTS: Coronary flow was significantly increased in both 1400W groups versus L
NAME (p < 0.001) and in high-dose 1400W versus control (p < 0.001). Coronary flow
was not significantly different between the nonischemic groups. Left ventricular
developed pressure was not significantly different among the ischemic groups or
between the two nonischemic groups. There were no differences in cyclic guanosine
monophosphate levels in any of the ischemic hearts. Myeloperoxidase levels were
significantly elevated in L-NAME versus high-dose 1400W, nonischemic 1400W, and
nonischemic saline groups (p < 0.02). CONCLUSIONS: Highly selective inhibition of
inducible nitric oxide synthase results in increased coronary flow after ischemia
but not after continuous perfusion. This occurs with decreased neutrophil
accumulation and a trend toward increased contractility without elevation of
cyclic guanosine monophosphate levels.
PMID- 9768924
TI - Preoperative predictors of cost in Medicare-age patients undergoing coronary
artery bypass grafting.
AB - BACKGROUND: Identification of preoperative factors that contribute to the cost of
coronary artery bypass grafting could aid in predicting the procedure's expense.
In this study, 30 sociodemographic and clinical preoperative factors were
examined with "survival analysis" techniques to determine characteristics related
to total hospital cost. METHODS: Characteristics of all patients age 65 or older
undergoing isolated coronary artery bypass grafting from July 1993 to April 1995
(n = 757) were recorded. Software was developed within the hospital's Transitions
Systems, Inc, database to calculate the outcome variable of total cost.
Nonparametric methods were used for the univariate analysis of the data, and the
Cox proportional hazards model was used for the multivariable analysis, censoring
25 patients who died in the hospital. RESULTS: Median hospital cost from the day
of the operation until discharge was $15,198. Median length of stay after the
operation was 6 days. Multivariable analysis revealed that age, preoperative
renal failure, history of cerebrovascular accident, low ejection fraction, and
surgical urgency were independent predictors of total cost. CONCLUSIONS: This
study, using an accurate representation of true hospital cost and a modeling
technique that accounts for the confounding effect of in-hospital death on cost,
provides a template for analysis of cost in other patient groups.
PMID- 9768925
TI - Modifying risk for extracorporeal circulation: trial of four antiinflammatory
strategies.
AB - BACKGROUND: Despite recent rediscovery of beating heart cardiac surgical
techniques, extracorporeal circulation remains appropriate for most heart
operations. To minimize deleterious effects of cardiopulmonary bypass,
antiinflammatory strategies have evolved. METHODS: Four state-of-the-art
strategies were studied in a prospective, randomized, preoperatively risk
stratified, 400-patient study comprising primary (n = 358), reoperative (n = 42),
coronary (n = 307), valve (n = 27), ascending aortic (n = 9), and combined
operations (n = 23). Groups were as follows: standard, roller pump, membrane
oxygenator, methylprednisolone (n = 112); aprotinin, standard plus aprotinin (n =
109); leukocyte depletion, standard plus a leukocyte filtration strategy (n =
112); and heparin-bonded circuitry, centrifugal pumping with surface modification
(n = 67). RESULTS: Analysis of variance, linear and logistic regression, and
Pearson correlation were applied. Actual mortality (2.3%) was less than half the
risk stratification predicted mortality (5.7%). The treatment strategies
effectively attenuated markers of the inflammatory response to extracorporeal
circulation. Compared with the other groups the heparin-bonded circuit had highly
significantly decreased complement activation (p = 0.00001), leukocyte filtration
blunted postpump leukocytosis (p = 0.043), and the aprotinin group had less
fibrinolysis (p = 0.011). Primary end points, length of stay, and hospital
charges, were positively correlated with operation type, age, pump time, body
surface area, stroke, pulmonary sequelae, predicted risk for stroke, predicted
risk for mortality, and risk strata/treatment group interaction (p = 0.0001). In
low-risk patients, leukocyte filtration reduced length of stay by 1 day (p =
0.02) and mean charges by $2,000 to $6,000 (p = 0.05). For high-risk patients,
aprotinin reduced mean length of stay up to 10 fewer days (p = 0.02) and mean
charges by $6,000 to $48,000 (p = 0.0007). CONCLUSIONS: These pharmacologic and
mechanical strategies significantly attenuated the inflammatory response to
extracorporeal circulation. This translated variably into improved patient
outcomes. The increased cost of treatment was offset for selected strategies
through the added value of significantly reduced risk.
PMID- 9768926
TI - Myocardial protection during antegrade versus retrograde cardioplegia.
AB - BACKGROUND: It has been suggested that the right ventricular myocardium is
suboptimally protected during retrograde blood cardioplegia. METHODS: Twenty
patients undergoing an elective coronary bypass procedure were randomized to
receive antegrade or retrograde mild hypothermic blood cardioplegia.
Transventricular differences in oxygen extraction, lactate production, and pH
were monitored during aortic cross-clamping, and myocardial biopsy specimens were
taken from both ventricles before cannulation and 15 minutes after aortic
declamping for analysis of adenine nucleotides and their breakdown products. The
extent of myocardial injury was estimated by monitoring postoperative leakage of
troponin T and the MB isoenzyme of creatine kinase. Hemodynamic recovery and
postoperative complications were noted. RESULTS: The preoperative characteristics
of the two groups were similar. Oxygen extraction and lactate production in the
right ventricular myocardium were higher in the retrograde group. In this group,
the right ventricle also extracted more oxygen and produced more lactate and acid
than did the left ventricle. Tissue levels of adenine nucleotides tended to
decrease in both ventricles during operation, with no differences between them.
The level of adenosine catabolites did increase somewhat in the right ventricular
myocardium of the retrograde cardioplegia group after aortic declamping. There
was a tendency for more prominent efflux of troponin T and the MB isoenzyme of
creatine kinase in the retrograde group. Nevertheless, the postoperative course
was uneventful in both groups. CONCLUSIONS: Retrograde mild hypothermic blood
cardioplegia leads to metabolic changes compatible with right ventricular
ischemia. Nevertheless, tissue levels of high-energy phosphates are well
preserved, and the postoperative course seems to be unproblematic. Care should be
taken when retrograde normothermic blood cardioplegia is provided for patients
with right ventricular hypertrophy, poor right ventricular function, or severe
preoperative myocardial ischemia.
PMID- 9768927
TI - Mitral valve replacement with the St. Jude Medical prosthesis: a 15-year follow
up.
AB - BACKGROUND: A retrospective study was conducted to analyze the results of St.
Jude Medical mitral valve replacement. METHODS: From January 1979 to December
1989, 870 patients (54% women, 46% men; mean age, 55.8 +/- 6.2 years) underwent
mitral valve replacement with the St. Jude Medical prosthesis. Of these
operations 616 were isolated mitral valve replacements and 254 were double valve
replacements. Coronary artery bypass grafting was performed concomitantly in 55
patients (6.3%). RESULTS: Overall, early mortality was 5.05%, with 4.2% for the
isolated mitral valve procedure and 7.08% for the double valve replacement.
Follow-up at 15 years was complete in 859 patients (98.74%). Mean follow-up time
was 93.5 months, for a total of 6,436 years. Actuarial survival at 15 years was
59.5% +/- 5%, 60.5% +/- 6%, and 56.9% +/- 9%, for the entire group, the isolated
mitral valve and double valve procedures, respectively. Multivariate analysis
identified age, sex, hospital stay, and preoperative mitral regurgitation as
independent prognosis factors for overall mortality. Of 606 patients alive at the
latest follow-up, the New York Heart Association class improved significantly
(from 67% class III/IV before the operation to 88% class I/II after the
operation). All patients received warfarin to maintain an international
normalized ratio between 3.5 and 4. The linearized rates (% per patient-year) of
thrombosis, thromboembolism, and major hemorrhage were, respectively, 0.21, 0.75,
and 0.94 for the entire group; 0.18, 0.67, and 0.88 for the isolated mitral valve
operation; and 0.15, 0.92, and 1.08 for the double valve replacement. For the
entire group the freedom from thrombosis and thromboembolism at 15 years was
98.1% +/- 1% and 88% +/- 4%, respectively. No case of structural dysfunction
occurred. The freedom from paravalvular leak and endocarditis at 15 years was
95.3% +/- 2% and 97.3% +/- 2.4%, respectively. The probability of remaining free
from reoperation at 15 years was therefore 95.6% +/- 2.5%. CONCLUSIONS: These
results confirm that the St. Jude Medical valve is a reliable prosthesis with
very low thrombosis and thromboembolism rates, allowing the use of a low dose of
anticoagulation with an international normalized ratio of about 3.
PMID- 9768928
TI - The adenosine-triphosphate-sensitive potassium-channel opener pinacidil is
effective in blood cardioplegia.
AB - BACKGROUND: This study was designed to evaluate the adenosine-triphosphate
sensitive potassium channel opener pinacidil as a blood cardioplegic agent.
METHODS: Using a blood-perfused, parabiotic, Langendorff rabbit model, hearts
underwent 30 minutes of normothermic ischemia protected with blood cardioplegia
(St. Thomas' solution [n = 8] or Krebs-Henseleit solution with pinacidil [50
micromol/L, n = 81) and 30 minutes of reperfusion. Percent recovery of developed
pressure, mechanical arrest, electrical arrest, reperfusion ventricular
fibrillation, percent tissue water, and myocardial oxygen consumption were
compared. RESULTS: The percent recovery of developed pressure was not different
between the groups (52.3 +/- 5.9 and 52.8 +/- 6.9 for hyperkalemic and pinacidil
cardioplegia, respectively). Pinacidil cardioplegia was associated with prolonged
electrical and mechanical activity (14.4 +/- 8.7 and 6.1 +/- 3.9 minutes),
compared with hyperkalemic cardioplegia (1.1 +/- 0.6 and 1.1 +/- 0.6 minutes,
respectively; p < 0.05). Pinacidil cardioplegia was associated with a higher
reperfusion myocardial oxygen consumption (0.6 +/- 0.1 versus 0.2 +/- 0.0 mL/100
g myocardium/beat; p < 0.05) and a higher percent of tissue water (79.6% +/- 0.7%
versus 78.6% +/- 1.2%; p < 0.05). CONCLUSIONS: Systolic recovery was not
different between groups, demonstrating comparable effectiveness of pinacidil and
hyperkalemic warm blood cardioplegia.
PMID- 9768929
TI - Operation for chronic traumatic aortic aneurysm: when and how?
AB - BACKGROUND: There are few guidelines for surgical intervention late after
unoperated traumatic aortic rupture. We reviewed our experience and the
literature to determine when and how to operate. METHODS: Between 1987 and 1997,
we treated 9 patients aged 22 to 82 years with chronic traumatic aneurysm. Seven
patients underwent aneurysm resection. Two patients have not been operated on.
The injury-to-operation interval ranged from 8 weeks to 18 years (mean, 4.1
years). One patient underwent median sternotomy and patch repair during
hypothermic circulatory arrest. Six patients underwent left thoracotomy: 2 were
operated on with left atrio-femoral bypass, and 4 with hypothermic circulatory
arrest and ascending aortic cannulation. RESULTS: There was no surgical mortality
or morbidity. The 2 patients who were not operated on remained asymptomatic
without radiologic change in the aneurysm after follow-up of 2 and 9 years.
CONCLUSIONS: From this limited experience and literature review, we make the
following subjective observations: (1) all patients with new symptoms should be
operated on promptly, and (2) asymptomatic densely calcified aneurysms detected
more than 2 years after the accident can be observed by repeated tomography
unless new symptoms arise.
PMID- 9768930
TI - Early and late risk factors in surgical treatment of acute type A aortic
dissection.
AB - BACKGROUND: Morbidity and mortality of emergency repair of type A dissecting
aneurysms of the aorta are high. This is an attempt to investigate the risk
determinants of early and late results. METHODS: A series of preoperative and
operative variables were retrospectively collected from the clinical records of
291 patients operated on between January 1, 1979, and December 31, 1995. Risk
factors for surgical death were investigated with univariate analysis and
stepwise logistic regression. Follow-up was conducted between December 1995 and
February 1996. Analysis of late results was conducted by means of actuarial
survival curves (life method). After removing the surgical deaths, risk factors
for late deaths were analyzed by a Cox model. RESULTS: The in-hospital mortality
rate was 36.1%. Significant independent determinants of operative or early death
were preoperative shock, preoperative neurologic impairment, operation before
1986, perioperative bleeding, and prolonged clamping time. The 10-year survival
rate was 36.9% +/- 4.4%. Twenty-six patients required repeat operation. The long
term prognosis was significantly worse in patients who needed reoperation.
CONCLUSIONS: Growing awareness of this disease and quicker diagnosis have
increased the number of patients with acute dissection of the ascending aorta who
are taken early to operation. This new challenge must be met by better
preoperative support and intraoperative monitoring, and by surgical techniques
that focus on lowering the rate of late complications, for which lifelong follow
up must be provided.
PMID- 9768931
TI - A dual-vent left heart deairing technique markedly reduces carotid artery
microemboli.
AB - BACKGROUND: Cerebral embolization, mainly bubbles, follows aortic declamping in
left heart valve operations. Embolization is not prevented by conventional left
heart deairing methods. We have validated a "dual-vent" deairing technique, which
uses high-flow left ventricular and aortic venting from the working heart into
the cardiopulmonary bypass venous line before aortic declamping. METHODS: After
left heart valve replacement, intraoperative color-flow Doppler echocardiography
was used to monitor the right common carotid embolic activity in 58 consecutive
patients who underwent conventional deairing (group 1), 14 consecutive patients
who underwent deairing by the dual-vent technique (group 2), and 4 patients who
received nonvented coronary artery bypass grafting who did not require deairing
(group 3). RESULTS: The median emboli count recorded after aortic declamping was
1,647 (range, 342 to 6,852) and 101 (range, 0 to 865) in the group 1 and 2
patients, respectively (p < 0.0001). The efficacy of the dual-vent technique
improved throughout the series: in the last 7 patients, the emboli counts often
approached the very low levels seen in group 3 patients (median, 8; range, 1 to
16). CONCLUSIONS: Cerebral embolization after aortic declamping in left heart
valve operations was significantly reduced by this dual-vent deairing technique.
PMID- 9768932
TI - Fibrinolysis-adjusted perioperative low-dose aprotinin reduces blood loss in
bypass operations.
AB - BACKGROUND: Postoperative bleeding still remains a serious problem in bypass
surgery. This study evaluated fibrinolysis and perioperative low-dose
antifibrinolytic regimens adjusted to the time course of fibrinolysis. METHODS:
In a prospective, randomized study of 42 patients undergoing bypass grafting,
patients received low-dose aprotinin (group A; n = 14) or low-dose tranexamic
acid (group TA; n = 14) intraoperatively and postoperatively, respectively, with
no antifibrinolytics for comparison (group C; n = 14). Parameters of
procoagulation, fibrinolysis, and activated factor VII were measured
preoperatively, intraoperatively, and postoperatively. Blood loss was determined
up to 24 hours. RESULTS: The level of thrombin-antithrombin III complex was
significantly decreased postoperatively in the treatment groups (group A and TA
versus C: 25 +/- 14 and 19 +/- 10 microg/L, respectively, versus 40 +/- 21
microg/L; p < 0.05). Levels of plasmin-antiplasmin complexes were significantly
decreased postoperatively in group A (607 +/- 231 microg/L) versus group C (825
+/- 225 microg/L) (p < 0.05) but were increased in group TA (1,145 +/- 394
microg/L) versus group C (p < 0.05). At all times intraoperatively and
postoperatively, levels of D-dimers were significantly decreased in group A and
group TA versus control (p < 0.001), indicating that fibrinolysis persists after
the operation. Intraoperatively, the factor VIIa level decreased significantly in
group A (20 +/- 8 mU/mL) versus group C (31 +/- 15 mU/mL) (p < 0.05), but not in
group TA (32 +/- 15 mU/mL). Blood loss was significantly lower in group A (135 +/
37 mL) and group TA (155 +/- 71 mL) versus group C (354 +/- 170 mL) (p < 0.001).
CONCLUSIONS: This low-dose aprotinin regimen adjusted to perioperative
fibrinolysis reduces blood loss significantly in coronary bypass grafting. For
further progress in this subject, clinical investigations of individual
fibrinolysis-adjusted antifibrinolytic treatment seems warranted.
PMID- 9768933
TI - Operative results after the Cox/maze procedure combined with a mitral valve
operation.
AB - BACKGROUND: There have been few reports on postoperative morbidity and mortality
analyses after concomitant mitral valve operation and the Cox/maze procedure.
METHODS: Between April 1993 and August 1995, 87 consecutive patients with chronic
atrial fibrillation underwent a mitral valve operation and concomitant Cox/maze
procedure at Iwate Medical University. The patients were divided into the
replacement group (n = 31) and repair group (n = 56) according to the method of
mitral valve replacement. Our initial experience with the combined operative
procedures is presented along with the operative mortality and morbidity rates.
Univariate analysis on preoperative and intraoperative variables affecting early
mortality and morbidity is carried out retrospectively. RESULTS: Total
cardiopulmonary bypass time in all patients was 177.2 +/- 70.1 minutes. Total
aortic cross-clamp time was 121.7 +/- 30.8 minutes. Total intensive care unit
stay was 5.3 +/- 7.9 days. The average intubation period was 55.5 +/- 187.6
hours. The intensive care unit stay and the intubation period of the replacement
group were longer than those of the repair group. There were four operative
deaths among the 87 patients (4.6%). All repair group patients survived
operation, whereas 4 replacement group patients died after operation. In all
patients, the New York Heart Association functional class was higher (p = 0.028)
in those who died than in those who survived. The overall restoration rate from
atrial fibrillation was 79.5% (66 of 83 survivors). Seventeen patients (20.5%)
had persistent atrial fibrillation postoperatively. Sick sinus syndrome occurred
in 7 patients (8.4%). In the repair group, the restoration rate was 76.8%,
whereas in the replacement group it was 85.2% for the survivors. CONCLUSIONS: The
Cox/maze procedure can be combined with a mitral valve operation with acceptably
low operative risk. Analysis of risk factors of early mortality revealed that the
type of mitral valve operation (replacement versus repair) and higher
preoperative New York Heart Association functional class were associated with
mortality. Long-term results from this combined procedure should be clearly
demonstrated before its universal acceptance.
PMID- 9768934
TI - Fifth-year hemodynamic performance of the prima stentless aortic valve.
AB - BACKGROUND: The medium-term hemodynamic performance of stentless valves has not
been widely reported, particularly in comparison with in vitro studies.
Therefore, we have assessed prospectively the hemodynamics of the Edwards Prima
valve in its fifth year after implantation in the aortic position, and compared
the results with those at 1 month after implantation and also with in vitro data.
METHODS: Thirty-five patients (age, 77 +/- 6 years; 19 men) were prospectively
studied by Doppler echocardiography at 1 month and 52 +/- 8 months after
implantation of a Prima stentless valve. Valve hemodynamics were assessed by
measuring the mean pressure gradient, mean valve resistance, and effective
orifice area. Left ventricular systolic function was quantified by ejection
fraction, the degree of hypertrophy by ventricular mass index, and the ratio of
ventricular wall thickness to cavity radius as a measure of ventricular geometry.
RESULTS: With a mean valve size of 24.6 +/- 2.2 mm in the fifth year after
implantation, the mean pressure gradient was 6.2 +/- 3.5 mm Hg, the mean valve
resistance, 29 +/- 16 dyne x s(-1) x cm(-5)), and the effective orifice area was
2.05 +/- 0.50 cm2. Compared with 1 month after operation, there was a 47%
decrease in mean valve resistance (p = 0.002) and a 39% increase in effective
orifice area (p = 0.001). Furthermore, both effective orifice area and mean valve
resistance in the fifth year did not differ from their in vitro counterparts,
whereas the left ventricular ejection fraction (0.64 +/- 0.14), the left
ventricular mass index (119 +/- 49 g/m2), and the ratio of ventricular wall
thickness to cavity radius (0.44 +/- 0.13) were within the normal range.
CONCLUSIONS: This study suggests that the Prima valve is a reliable stentless
aortic bioprosthesis. This is supported by a favorable medium-term clinical
outcome, durable hemodynamic performance, and normal mean values of left
ventricular ejection fraction and mass index in the fifth year after
implantation.
PMID- 9768935
TI - Surgical experience with intracardiac myxomas: long-term follow-up.
AB - BACKGROUND: Myxomas are the most common benign intracardiac tumors. This report
summarizes our 20-year experience with these tumors. METHODS: Sixty-six patients
(25 male) with a median age of 39 years (range, 6 to 70 years) underwent surgical
excision of primary or recurrent intracardiac myxomas during the years 1976 to
1996. Symptom duration ranged from 2 to 8 months. There were 55 left atrial
myxomas, 10 right atrial myxomas, and 1 biatrial myxoma. Three of the patients
were in one family. The surgical approach comprised complete wide excision.
RESULTS: There were two early deaths. Late follow-up is 89% (57/64) complete.
There was one late death, which was not due to a cardiac cause. Echocardiography
at a mean follow-up of 66.9 months (range, 7 to 241 months) showed no recurrence
of sporadic myxomas. However, 2 of the 3 patients with familial myxomas had
recurrence. CONCLUSIONS: Surgical excision of atrial myxoma gives excellent short
term and long-term results leading to eventual cure of nonfamilial myxomas.
However, familial myxomas retain a strong tendency to recur even 20 years after
excision.
PMID- 9768936
TI - Gene transfer to vein graft wall by HVJ-liposome method: time course and
localization of gene expression.
AB - BACKGROUND: A novel gene transfer method using liposomes with a viral envelope of
hemagglutinating virus of Japan (HVJ) has been reported to be very effective for
gene transfection into somatic cells and might be applicable to improve the
patency of vein grafts. The present study examined the time course and
localization of gene expression to assess the feasibility of ex vivo gene
transfer into the vein graft by the HVJ-liposome method. METHODS: The HVJ
liposome complex containing either beta-galactosidase plasmid DNA
(deoxyribonucleic acid) or no genes (controls) (experiment 1) or fluorescein
isothiocyanate-labeled oligonucleotides either with or without HVJ-liposomes
(experiment 2) was infused into rabbit vein grafts and allowed to incubate before
autologous transplantation to carotid arteries. RESULTS: In experiment 1, all
grafts incubated with beta-galactosidase plasmid with HVJ-liposomes showed the
blue staining of X-gal 7 days after operation, whereas the controls did not. The
blue granules were present in the medial and adventitial tissue and were still
present after 14 days. In experiment 2, many fluorescein isothiocyanate-labeled
nuclei were observed in the graft wall 2 and 4 days after operation and remained
present mainly in the media of HVJ-liposome-treated grafts after 7 and 14 days,
when no fluorescein isothiocyanate activity was observed without HVJ-liposome
treatment. CONCLUSIONS: These results demonstrated the feasibility of ex vivo
transfection to the medial and adventitial tissue of the vein graft by the HVJ
liposome method and suggest the possibility of its clinical application to
prevent vein graft failure.
PMID- 9768937
TI - Effect of modified ultrafiltration in high-risk patients undergoing operations
for congenital heart disease.
AB - BACKGROUND: Modified ultrafiltration (MUF) after cardiopulmonary bypass (CPB) in
children decreases body water, removes inflammatory mediators, improves
hemodynamics, and decreases transfusion requirements. The optimal target
population for MUF needs to be defined. This prospective, randomized study
attempted to identify the best candidates for MUF during operations for
congenital heart disease. METHODS: Informed consent was obtained from 100
consecutive patients with complex congenital heart disease undergoing operations
with CPB. They were randomized into a control group (n = 50) of conventional
ultrafiltration during bypass and an experimental group using dilutional
ultrafiltration during bypass and venovenous modified ultrafiltration after
bypass (MUF group, n = 50). Postoperative arterial oxygenation, duration of
ventilatory support, transfusion requirements, hematocrit, chest tube output, and
time to chest tube removal were compared between the groups stratified by age and
weight, CPB technique, existence of preoperative pulmonary hypertension, and
diagnosis. RESULTS: There were no MUF-related complications. In patients with
preoperative pulmonary hypertension, MUF significantly improved postoperative
oxygenation (445 +/- 129 mm Hg versus control: 307 +/- 113 mm Hg, p = 0.002),
shortened ventilatory support (42.9 +/- 29.5 hours versus control: 162.4 +/-
131.2 hours, p = 0.0005), decreased blood transfusion (red blood cells: 16.2 +/-
18.2 mL/kg versus control: 41.4 +/- 27.8 mL/kg, p = 0.01; coagulation factors:
5.3. +/- 6.9 mL/kg versus control: 32.3 +/- 15.5 mL/kg, p = 0.01), and led to
earlier chest tube removal. In neonates (< or =30 days), MUF significantly
reduced transfusion of coagulation factors (5.4 +/- 5.0 mL/kg versus control:
39.9 +/- 25.8 mL/kg, p = 0.007), and duration of ventilatory support (59.3 +/-
36.2 hours versus 242.1 +/- 143.1 hours, p = 0.0009). In patients with prolonged
CPB (>120 minutes), MUF significantly reduced the duration of ventilatory support
(44.7 +/- 37.0 hours versus 128.7 +/- 133.4 hours, p = 0.002). No significant
differences were observed between MUF and control patients for any parameter in
the presence of ventricular septal defect without pulmonary hypertension,
tetralogy of Fallot, or aortic stenosis. CONCLUSIONS: Modified ultrafiltration
after CPB is safe and decreases the need for homologous blood transfusion, the
duration of ventilatory support, and chest tube placement in selected patients
with complex congenital heart disease. The optimal use of MUF includes patients
with preoperative pulmonary hypertension, neonates, and patients who require
prolonged CPB.
PMID- 9768939
TI - Does banding the pulmonary artery affect pulmonary valve function after the Damus
Kaye-Stansel operation?
AB - BACKGROUND: The Damus-Kaye-Stansel (DKS) operation can be an effective palliation
in patients who have single-ventricle physiology and systemic outflow
obstruction. Pulmonary artery banding (PAB) may be used as a preliminary
procedure in these patients to limit overperfusion of the pulmonary circulation.
In some series, the DKS operation has been associated with pulmonary
insufficiency (PI). We retrospectively analyzed medical records of our patients
who had PAB and later DKS to determine the incidence of PI in these patients.
METHODS: Between 1982 and 1996, 15 patients underwent PAB before DKS. Median age
at PAB placement was 7 days and median duration of PAB was 7 months.
Echocardiograms obtained before PAB, before DKS, and at the most recent post-DKS
follow-up were reviewed. RESULTS: Follow-up ranged from 1 to 15 years (mean
follow-up, 7.5 years). One patient had trivial PI before PAB, which progressed to
moderate PI at the last follow-up. Only 1 other patient had mild PI, but only at
the last follow-up after DKS. CONCLUSIONS: These findings suggest that prior PAB
does not appear to cause significant PI in patients slated for DKS, and the
incidence of significant PI after the DKS operation is relatively low.
PMID- 9768938
TI - Primum atrial septal defect in children: early results, risk factors, and freedom
from reoperation.
AB - BACKGROUND: Repair of primum atrial septal defect in children usually is
associated with a low operative mortality, except for a subgroup of children with
congestive heart failure. To determine the early mortality and incidence of
reoperation in children with primum atrial septal defect, we analyzed
retrospectively the results of patients who underwent repair of this defect.
METHODS: Between July 1982 and December 1996, 180 children underwent repair of
primum atrial septal defect. The mean age at repair was 4.6 years (median, 3.6
years; range, 1 month to 16.4 years); of the 180 children, 23 were infants less
than 1 year of age. Absent or mild symptoms were present in 145 (80%), whereas 34
(20%) of children presented with severe symptoms or congestive heart failure.
RESULTS: Early mortality occurred in 3 (1.6%); 2 were less than 1 year of age.
Follow-up ranged from 2 months to 14.5 years (mean, 6 +/- 4.2 years). Actuarial
survival is 98% at 10 years with no late deaths. Age less than 1 year is a
predictor of death. During follow-up, 17 (9%) of the 180 patients underwent
reoperation, 5 of whom were in the infant group. Five underwent reoperation for
subaortic obstruction, and 12 for left atrioventricular valve regurgitation of
whom 11 were repaired; and 1 required valve replacement. Age and preoperative
moderate-to-severe left atrioventricular valve regurgitation were predictors of
reoperation. CONCLUSIONS: Results of the repair of primum atrial septal defect
during childhood are favorable. Infants have a higher risk for death and
reoperation. Left atrioventricular valve insufficiency and subaortic stenosis are
important late complications and can be repaired safely at reoperation.
PMID- 9768940
TI - Arterial switch in hearts with left ventricular outflow and pulmonary valve
abnormalities.
AB - BACKGROUND: Pulmonary valve and left ventricular outflow tract abnormalities
(LVOT) may not be absolute contraindications to arterial switch operation (ASO).
METHODS: In this study we analyze long-term outcome for 26 such transposition
patients (6.3% of our ASO cohort). Median age and weight were 69 days (7 to 3,631
days) and 4.5 kg (2.6 to 34 kg). Pulmonary valve abnormalities included bicuspid
valve (n = 4) and dysplastic valve (n = 5). The LVOT abnormalities (n = 17)
included accessory atrioventricular valve/endocardial cushion tissue,
fibromuscular ring, anomalous muscle bands, and septal malalignment. Patients
with dynamic LVOT obstruction were excluded. The median preoperative left
ventricular to pulmonary artery peak systolic pressure gradient was 30 mm (0 to
93 mm), or 50 mm (16 to 93 mm) if patients with isolated valve abnormalities are
excluded. The ASO was performed according to our standard technique with or
without LVOT resection or pulmonary valvotomy as required. RESULTS: There were
two perioperative deaths (7.7%; 95% confidence interval, 0.9% to 25%), and no
late deaths during 1,934 patient-months of follow-up time. Actuarial freedom from
reoperation for neoaortic valve or LVOT problems is 87% (+/- 7) at 130 months,
representing two reoperations. One was performed for neoaortic insufficiency plus
LVOT obstruction, and the other for isolated LVOT obstruction. One patient
currently has significant neoaortic insufficiency, and median gradient at last
follow-up is 0 mm Hg (range, 0 to 35 mm Hg). CONCLUSIONS: The ASO can be
performed in selected patients with transposition of the great arteries and with
LVOT abnormalities with early and late survival and functional status similar to
that of matched patients with normal pulmonary valves and LVOT (p > 0.05), but
with a greater hazard for reoperation (p < 0.05). Selection for ASO should be
based on anatomic criteria rather than left ventricular to pulmonary artery
gradient alone, to avoid assigning these patients with transposition of the great
arteries to treatment strategies less satisfactory than ASO.
PMID- 9768941
TI - Homograft replacement of mitral valve in children.
AB - BACKGROUND: Recent reports have demonstrated successful early outcomes using
mitral valve homografts in adults. We report our early results after homograft
mitral valve replacement in 4 children with previous atrioventricular septal
defects, previous placement of a prosthetic valve, and rheumatic valvular
disease. METHODS: Between May 1996 and June 1997, 4 children (ages 5, 11, 13, and
15 years) underwent mitral valve replacement with cryopreserved mitral valve
homografts at our institution. Preoperative echocardiography confirmed moderately
severe to severe mitral regurgitation, stenosis, or both in all 4 patients.
RESULTS: Successful homograft valve replacement was achieved in all 4 patients.
Based on symptoms, physical examinations, and echocardiographic follow-up, all
four homograft mitral valves are functioning well with normal hemodynamics. None
of these patients are receiving warfarin. Follow-up has been limited to 10
months. CONCLUSIONS: In children requiring mitral valve replacement, the use of
mitral valve homografts offers advantages over prosthetic valves, such as the
avoidance of complications associated with thrombosis and anticoagulation.
Homograft mitral valve replacement is technically feasible in children with
congenital and rheumatic heart disease and previous prosthetic valves.
PMID- 9768942
TI - Video-assisted thoracoscopic ligation of patent ductus arteriosus: safe and
outpatient.
AB - BACKGROUND: Minimally invasive techniques for interruption of patent ductus
arteriosus have been reported, but are in use at only a few centers. We examined
our series of patients who underwent thoracoscopic patent ductus arteriosus
ligation. METHODS: We reviewed 59 consecutive patients, age 6 days to 50 years,
weighing 640 g to 62 kg, who underwent video-assisted placement of a stainless
steel clip across the patent ductus arteriosus. RESULTS: Thirty-eight nonneonates
and 21 neonates (18 were < or =1,500 g) underwent video-assisted thoracic surgery
for patent ductus arteriosus closure with intraoperative echocardiographic
confirmation in nonneonates. There were no residual shunts, transfusions,
chylothoraces, or significant pneumothoraces. Four were converted to thoracotomy,
3 for anatomic variances, and 1 for coagulopathy. Thirty-six of 38 nonneonate
patients stayed less than 24 hours; 18 were discharged the evening of the
operation. Two were admitted, one after thoracotomy, and one for a small mucosal
intubation injury. No others required a chest tube. There were two recurrent
nerve injuries. All neonates survived, and were extubated. CONCLUSIONS: Video
assisted thoracoscopic ductus closure is a safe, reliable technique and can be
performed as an outpatient procedure in nonneonate patients.
PMID- 9768943
TI - Validation of relative value scale for congenital heart operations.
AB - BACKGROUND: To determine the validity of the newly assigned work relative value
unit (RVU) scale for surgical procedures for congenital heart disease, we
measured its relationship to length of hospital stay, total hospital charges, and
mortality. METHODS: We identified cases by the presence of ICD-9-CM codes in nine
statewide, administrative hospital discharge abstract databases for 1992.
Computer algorithms were generated to assign RVUs to individual cases. Spearman
correlation coefficients between work and practice expense RVUs and median length
of hospital stay, total hospital charges, and in-hospital mortality were
determined, as well as parameter estimates from linear and logistic regression.
RESULTS: Using data from 5,192 cases involving 34 surgical procedures for
congenital heart disease, higher work RVUs were associated with longer lengths of
hospital stay (rs = 0.72, p < 0.0001), higher total hospital charges (rs = 0.81,
p < 0.0001), and higher in-hospital mortality (rs = 0.45, p = 0.01). A 5-point
increase in the relative value scale was associated with an increase in the
length of stay by a multiplicative factor of 1.3 (p < 0.0001); total hospital
charges by 1.5 (p < 0.0001); and the odds of in-hospital death by 1.9 (p <
0.0001). Findings were similar for practice expense RVUs, as work and practice
expense RVUs were highly correlated (rs = 0.93, p < 0.0001). CONCLUSIONS: The
group of work RVUs for surgical procedures for congenital heart defects are
reasonable relative measures, on average, of physician work for these procedures,
thus supporting the use of this scale to determine physician reimbursement.
Practice expense RVUs may not be an independent measure for these procedures.
PMID- 9768944
TI - Association between age and blood loss in children undergoing open heart
operations.
AB - BACKGROUND: Although recent studies indicated young children are at risk for
increased perioperative hemorrhage after open heart operations, the associations
between patient age, blood loss and blood product transfusions have not been
fully defined in children. METHODS: Perioperative blood loss and blood product
transfusion data were recorded for 414 consecutive children undergoing open heart
procedures. The children were in the following age groups: 1 month or younger,
group 1; older than 1 month to 12 months, group 2; older than 1 year to 5 years,
group 3; and older than 5 years, group 4. RESULTS: Postoperative blood loss and
blood product transfusions were inversely related to age and differed
significantly between the four age groups. Multiple preoperative and
intraoperative factors that possibly influence hemostasis also differed
significantly between age groups. Median units transfused within 72 hours
differed significantly with age (p < 0.0001): group 1, 8 units (range, 1 to 19
units); group 2, 6 units (range, 0 to 21 units); group 3, 2 units (range, 0 to 23
units); and group 4, 0 units (range, 0 to 38 units). CONCLUSIONS: Blood loss and
transfusions vary inversely with age. Per kilogram of body weight, neonates bled
more and received more donor products than any other age group.
PMID- 9768945
TI - Controlled reperfusion prevents pulmonary injury after 24 hours of lung
preservation.
AB - BACKGROUND: Posttransplantation lung reperfusion injury continues to be a major
problem. We have shown that controlling the initial period of reperfusion limits
this injury after 2 hours of warm lung ischemia. The effectiveness of this
modality, however, is unknown after longer periods of cold ischemia, which more
closely mimics the clinical situation. METHODS: After baseline measurements, 10
pigs had the left lung flushed with a modified Euro-Collins solution, explanted,
stored at 4 degrees C for 24 hours, and transplanted into 10 other pigs. Five
(group 1) underwent uncontrolled reperfusion created by removal of the vascular
clamps after implantation of the new left lung, mimicking the clinical situation.
The other five (group 2) underwent controlled reperfusion, which we performed by
taking blood from the femoral artery, mixing it with a crystalloid solution
(using a mixer heater) to make the blood hyperosmolar, alkalotic, and substrate
enriched, and pumping it through a leukocyte-depleting filter into the
transplanted lung for 10 minutes at a pressure of 20 to 30 mm Hg before removing
the pulmonary artery clamp. The right pulmonary artery and bronchus were then
ligated, and left lung function was assessed each hour for 4 hours and compared
with baseline. RESULTS: Controlled reperfusion (group 2) minimized the
reperfusion injury, preserving posttransplant pulmonary compliance (92% +/- 1%
versus 68% +/- 1%; p < 0.001), reducing the rise in pulmonary vascular resistance
(27% +/- 2% versus 166% +/- 3%; p < 0.001), improving oxygenation (PO2, 425 +/-
14 versus 82 +/- 11 mm Hg; p < 0.001), and lowering myeloperoxidase activity
(0.22 +/- 0.02 versus 0.45 +/- 0.02 deltaOD/mg protein per minute; p < 0.001) and
tissue edema (83.0% +/- 0.3% versus 84.9% +/- 0.3%; p < 0.001) compared with
uncontrolled reperfusion, which resulted in an injury so severe that 3 of 5 pigs
died before the 4-hour measurements. CONCLUSIONS: After 24 hours of cold ischemia
uncontrolled reperfusion results in a severe pulmonary reperfusion injury. This
injury is almost completely avoided by controlling the composition (modified
solution and white blood cell filter) and conditions (pressure) of the
reperfusion. Because this experiment mimics the clinical situation, it suggests
surgeons should begin to use this modality to limit reperfusion injury after lung
transplantation.
PMID- 9768946
TI - Detection of extrathoracic metastases by positron emission tomography in lung
cancer.
AB - BACKGROUND: Accurate staging of non-small cell lung cancer is essential for
treatment planning. We evaluated in a prospective study the role of whole-body 2
[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in
mediastinal nodal staging with a positive predictive value of 96%. The study was
continued to further evaluate the value of whole-body FDG PET in detecting
unexpected extrathoracic metastases (ETMs) in patients qualifying for surgical
treatment by conventional staging. METHODS: One hundred patients underwent
clinical evaluation, chest and upper abdominal computed tomography scan,
mediastinoscopy (lymph nodes greater than 1 cm on computed tomography), and
routine laboratory tests. In 94 patients with stage IIIa or less and 6 with
suspected N3 a whole-body FDG PET was performed. If clinical signs of ETMs were
present additional diagnostic methods were applied. All findings in the FDG PET
were confirmed histologically or radiologically. RESULTS: Unexpected ETMs were
detected in 13 (14%) of 94 patients (stage IIIa or less) at 14 sites. In addition
6 of 94 patients were restaged up to N3 after PET. The suspected N3 disease
(stage IIIb) on computed tomography was confirmed by PET in all 6 patients. There
was no false positive finding of ETM. Weight loss was correlated with the
occurrence of ETM: more than 5 kg, 5 of 13 patients (38%); more than 10 kg, 4 of
6 patients (67%). Pathologic laboratory findings were not predictive for ETM.
CONCLUSIONS: Whole-body FDG PET improves detection of ETMs in patients with non
small cell lung cancer otherwise elegible for operation. In 14% of patients
(stage IIIa or less), ETMs were detected, and in total, 20% of the patients were
understaged.
PMID- 9768947
TI - Leiomyosarcoma of the esophagus: results of surgical treatment.
AB - BACKGROUND: This study examined the results of surgical treatment of
leiomyosarcoma of the esophagus. METHODS: Between January 1920 and December 1996,
17 patients (9 men and 8 women) with leiomyosarcoma of the esophagus were treated
surgically at the Mayo Clinic. Median age was 58 years and ranged from 26 to 76
years. Symptoms included dysphagia in 11 patients (64.7%) and odynophagia in 6
(35.3%). The tumor was located in the middle third of the esophagus in 10
patients (58.8%) and in the cervical esophagus in 7 (41.2%). Procedures performed
included esophagogastrectomy in 9 patients (Ivor Lewis in 5, left
thoracoabdominal in 3, and transhiatal in 1), enucleation in 3, transgastric
excision in 1, and exploration without resection in 4. RESULTS: The procedure was
considered curative in 11 patients (64.7%). There was one operative death
(mortality, 5.9%). Complications occurred in 3 patients (17.6%) and included
anastomotic leak in 2 and bleeding requiring reoperation in 1. Growth pattern was
infiltrating in 7, polypoid in 5, and intramural in 5. Histologically, the tumor
was grade 1 in 6 patients, grade 2 in 2, grade 3 in 7, and grade 4 in 2. The
tumor was postsurgically classified as stage I in 2 patients, stage IIA in 7,
stage IIB in 1, stage IIIA in 5, stage IV in 1, and unknown in 1. Six patients
(35.3%) received adjuvant treatment. Follow-up was complete in 16 patients
(94.1%) and ranged from 1 to 182 months (median, 48 months). Five- and 10-year
actuarial survivals were 47.0% and 31.0%, respectively. Seven patients (41.2%)
are currently alive (median survival, 72 months); all underwent curative
resection. Factors affecting survival included completeness of resection, growth
pattern, postsurgical stage, tumor grade, and tumor location (p < 0.05).
CONCLUSIONS: We conclude that leiomyosarcoma of the esophagus is rare. Complete
resection provides long-term survival.
PMID- 9768948
TI - Lobectomy improves ventilatory function in selected patients with severe COPD.
AB - BACKGROUND: Patients often undergo limited resection instead of lobectomy for non
small cell lung cancer because of a low preoperative forced expiratory volume in
1 second (FEV1). Our goal is to define criteria that will preoperatively identify
a group of patients who will not lose further function after lobectomy. METHODS:
Patients who underwent lobectomy with a preoperative FEV1 of less than 80% of
predicted were retrospectively identified. Data collected included preoperative
and postoperative pulmonary function tests, age, sex, the lobe resected, and
preoperative ventilation-perfusion scan result. RESULTS: Thirty-two patients were
included in this study. The median preoperative FEV1 was 60% of predicted (1.65
L) and the mean change in FEV1 was a loss of 7.8% after lobectomy. The patients
were divided into two groups. Group 1 (n = 13) had a preoperative FEV1 of less
than or equal to 60% of predicted (median, 49%; 1.35 L) combined with an FEV1 to
forced vital capacity ratio of less than or equal to 0.6. Group 2 (n = 19)
includes all other patients (median preoperative FEV1, 69% of predicted; 1.87 L).
The mean changes in FEV1 after lobectomy were +3.7% and -15.7% for groups 1 and
2, respectively (p < 0.005). A chronic obstructive pulmonary disease index was
defined and then calculated for each patient. The relationship between this index
and the change in FEV1 after lobectomy for all 32 patients appears linear (r =
0.43; p = 0.015). CONCLUSIONS: Patients with a very low preoperative FEV1 and
FEV1 to forced vital capacity ratio are less likely to lose ventilatory function
after lobectomy and may actually improve it.
PMID- 9768949
TI - Isolated lung liposome-mediated gene transfer produces organ-specific transgenic
expression.
AB - BACKGROUND: Gene therapy is a promising strategy for the treatment of inoperable
pulmonary tumors and rejection after lung transplantation. However, unlike ex
vivo administration, intravenous in vivo transfection lacks organ specificity and
has a limited duration of expression. The objectives of this study were to limit
transfection to a single lung and to increase the duration of gene expression in
vivo. METHODS: Sixteen male Fisher rats were anesthetized and divided into two
groups. Animals in group I (n = 7) received an intrajugular administration of
1,320 microg of chloramphenicol acetyl transferase (CAT) complementary DNA
complexed with cationic liposomes. Animals in group II (n = 9) received 660
microg of CAT complementary DNA complexed with cationic liposomes into the
pulmonary artery of an isolated left lung over 10 minutes. After 40 minutes of
incubation, the lung was flushed with 10 mL of normal saline solution, and the
perfusate was suctioned through a left pulmonary venotomy. The circulation to the
left lung was then restored. After 48 hours, the animals were divided into
subgroups (a and b) and CAT activity was assessed in the lungs, hearts, livers,
and kidneys of groups Ia (n = 3) and IIa (n = 5). After 21 days, CAT activity was
assessed in the left lungs of groups Ib (n = 4) and IIb (n = 4). RESULTS: After
48 hours, animals that had received intravenous administration of CAT cDNA showed
strong expression in the lungs and hearts and negligible expression in the livers
and kidneys. In contrast, animals in group IIa, which had received isolated left
lung perfusion of CAT cDNA showed expression only in the left lung. After 21
days, the left lungs of animals in group Ib, which had received intravenous
administration of CAT complementary DNA, showed no CAT expression, but the left
lungs of animals in group IIb, which had received isolated left lung perfusion of
CAT complementary DNA, exhibited strong CAT expression. CONCLUSIONS: Compared
with intravenous administration, isolated lung liposome-mediated gene transfer
provides prolonged organ-specific gene expression. This provides a useful model
to study the effects of gene therapy on pulmonary tumors, which may have further
application when gene therapy is used in clinical practice.
PMID- 9768950
TI - Reoperative pulmonary metastasectomy for sarcomatous pediatric histologies.
AB - BACKGROUND: The role for reoperative pulmonary metastasectomy in patients with
"pediatric sarcomas" (osteosarcoma, nonrhabdomyosarcoma-soft tissue sarcoma, and
Ewing's sarcoma) is undefined. METHODS: We reviewed our results for patients with
these histologic presentations (median age, 17.5 years; range, 6 to 32 years)
having two (70), three (27), or four (10) metastasectomies between January 1965
and March 1995 to define postresection survival and potential prognostic factors.
Simple wedges (88 thoracotomies, 84%) were performed more frequently than
anatomic (17 thoracotomies, 16%) resections. RESULTS: With a median potential
follow-up of 12.7 years, median survival was 2.25, 3.60, and 0.96 years from the
second, third, and fourth explorations, respectively. Primary tumor site, sex,
histology, age, maximal metastasis size, and systemic chemotherapy did not
influence survival. Resectability was the most important prognostic factor (5.6
versus 0.7 years, 5.2 versus 2.5 years, 2.2 versus 0.2 years, resectable versus
unresectable, median survival from second, third, and fourth thoracotomy,
respectively). Unresectability, disease-free interval less than 6 months between
initial (ie, first) pulmonary resection and the second thoracotomy, and two or
more preoperative nodules noted on the right were simultaneously negatively
associated with survival from the second thoracotomy. Unresectability or finding
two or more metastases negatively affected survival from the third thoracotomy.
CONCLUSIONS: These data imply that repeat metastasectomy can salvage a subset of
patients with sarcomatous pediatric histologic presentations who retain favorable
prognostic determinants.
PMID- 9768951
TI - Standardized clinical care pathways for major thoracic cases reduce hospital
costs.
AB - BACKGROUND: Standardized clinical care pathways have been developed for
postoperative management in an attempt to contain costs in an era of rising
health care costs and limited resources. The purpose of this study was to assess
the effect of these pathways on length of stay, hospital charges, and outcome for
major thoracic surgical procedures. METHODS: All anatomic lung (segmentectomy,
lobectomy, and pneumonectomy) and partial and complete esophageal resections
performed from July 1991 to July 1997 were retrospectively analyzed for length of
stay, hospital charges, and outcome. A prospectively developed database was used.
Clinical care pathways were introduced in March 1994. Comparisons were made
between the procedures performed before (group I) and after (group II) pathway
implementation. Common to both pathways are early mobilization and prudent x-ray
and laboratory analysis. In addition, the pathway for esophagectomies emphasizes
overnight intubation with 24-hour intensive care unit care, and staged diet
advancement. The discharge goal was postoperative day 10. For lung resection the
emphasis is early postoperative extubation with overnight intensive care unit
management. The discharge goal was postoperative day 7. RESULTS: Group I
esophagectomies (n = 56) had significantly greater hospital charges compared with
group II (n = 96) ($21,977 +/- $13,555 versus $17,919 +/- $5,321; p < 0.04, in
actual dollars) and ($29,097 +/- $18,586 versus $19,260 +/- $6,000; p < 0.001, in
dollars adjusted for inflation) and greater length of stay (13.6 +/- 6.9 versus
9.5 +/- 2.8 days; p < 0.001). Group I lung resections (n = 185) had a
significantly greater length of stay compared with group II (n = 241) (8.0 +/-
6.2 versus 6.4 +/- 3.8 days; p < 0.002); although charges trended downward
($13,113 +/- $10,711 versus $12,404 +/- $7,189; not significant) in actual
dollars, charges were significantly less in dollars adjusted for inflation
($17,103 +/- $13,211 versus $13,432 +/- $8,056; p < 0.01). The most significant
decreases in charges for esophagectomies were in miscellaneous charges (61% in
dollars adjusted for inflation), pharmaceuticals (60%), laboratory (42%) and
radiologic (39%) tests, physical therapy charges (35%), and routine charges
(34%). For lung resections the greatest savings occurred for pharmaceuticals
(38%), supplies (34%), miscellaneous charges (25%), and routine charges (22%).
Mortality was similar (esophagectomies: I, 3.6%; II, 0%; lung resections: I,
0.5%; II, 0.8%; not significant). CONCLUSIONS: Introduction of standardized
clinical pathways has resulted in a marked reduction of length of stay for all
major thoracic surgical procedures. Total charges were reduced for both
esophagectomies (34%) and lung resections (21%) with continued quality of
outcome.
PMID- 9768952
TI - Axillary lymph node metastases from bronchogenic carcinoma.
AB - BACKGROUND: Axillary lymph node metastases (ALNMs) from bronchogenic carcinoma
are rare and their significance may be questioned. A surgical approach may allow
a better understanding of the mechanism of their occurrence. METHODS: A
retrospective study of 1,486 cases of surgically removed non-small cell lung
carcinoma was performed. Twenty-two patients (1.5%) had extrathoracic nodal
metastases. Nine of them were ALNMs (<1%). These cases form the basis of this
study. RESULTS: In 1 patient ipsilateral ALNM was removed during a lung
operation. It was a left non-small cell lung carcinoma invading the chest wall
(T3 N2). In the other patients (n = 8) ALNMs were observed during postoperative
follow-up; 4 underwent ALNM resection, 2 had radiotherapy, and 2 had symptomatic
treatment only. For these 8 patients, in the TNM classification performed after
an initial bronchogenic carcinoma operation, the lymph node status was,
respectively, N0 in four cases, N1 in three cases, and N2 in one case. Survival
ranged from 1 to 10 months, except for one patient who is still alive after more
than 5 years. In this case, the ALNM was discovered 4 months after a right lower
lobectomy for a T2 N0 adenocarcinoma. CONCLUSIONS: Axillary lymph node metastases
may be involved through direct chest wall invasion of bronchogenic carcinoma or
retrograde spread from supraclavicular lymphnode block. However, another
mechanism seems to be the systemic vascular route.
PMID- 9768953
TI - Endoscopic treatment of postoperative bronchopleural fistula: experience with 45
cases.
AB - BACKGROUND: The value of bronchoscopic sealing of bronchopleural fistulas was
studied retrospectively. METHODS: The cases of 45 patients seen between 1983 and
1996 with bronchopleural fistula after pneumonectomy (40 patients) or lobectomy
(5 patients) were reviewed. Age, underlying disease, side, fistula size
(millimeters) at initial bronchoscopy, survival (days) after endoscopic
treatment, mode and number of endoscopic interventions, interval (days) between
operation and fistula occurrence, and pathologic TNM stage in the case of
malignancy were recorded. On the basis of the therapeutic outcome (cure, death,
chronic empyema with closed fistula, or chronic empyema with open fistula) and
the modality (successful sealing or bronchoscopic failure with subsequent
surgical intervention), various groups were assessed and compared. RESULTS: Of 29
patients (64%) treated only endoscopically, 9 were cured. Seven patients had
fistula closure, but persistent chronic empyema necessitated permanent drainage.
In another 7 patients, the fistula remained open and also was controlled by
permanent drainage. Six patients in this group died. The overall rate of fistula
closure was 35.6% (16 patients), and recurrence occurred in 2 patients. Sixteen
patients (35.6%) required surgical intervention because of increasing fistula
size (8 patients), sepsis with refractory empyema (7), and fecal empyema (1
patient). Two patients in the surgical group died. Small fistulas (<3 mm)
responded particularly well to primary endoscopic treatment. CONCLUSIONS:
Bronchoscopic treatment of bronchopleural fistula appears an efficient
alternative, especially when surgical intervention cannot be done because of the
physical condition of the patient.
PMID- 9768954
TI - Tracheal mucoepidermoid carcinoma in a 7-year-old child.
AB - Mucoepidermoid cancers are rare tumors that arise from the serous and mucous
glands of the upper airway and salivary glands. Patients, especially children,
with tumors that arise in the trachea and upper airways are often misdiagnosed as
asthmatic and are treated with bronchodilators without resolution. A 7-year-old
girl who had been diagnosed as asthmatic was subsequently found to have a
mucoepidermoid tumor of the trachea. She underwent a successful tracheal
resection and remains tumor free on follow-up bronchoscopy at 16 months.
PMID- 9768955
TI - An unexpected complication after harvesting of the radial artery for coronary
artery bypass grafting.
AB - Acute ischemia of the hand developed after coronary artery bypass grafting with a
radial artery conduit. Perioperative tests established that there was good
perfusion to the hand via the collateral vessels. Angiographic examination showed
an absence of the ulnar artery. Circulation was restored with a vein graft. I
briefly review noninvasive investigations available and suggest that color
Doppler scanning should be routinely performed before the use of the radial
artery as a conduit.
PMID- 9768956
TI - Interleukin-6 and "complex" cardiac myxoma.
AB - A rare case of "complex" cardiac myxoma is reported. Complex cardiac myxoma
manifests with more constitutional signs than the sporadic type. These
constitutional signs are known to be associated with the overproduction of
interleukin-6 by cardiac myxomas. In our study, immunohistochemical staining of
the myxoma for interleukin-6 was strongly positive. The serum interleukin-6 level
decreased after surgical removal of the tumor and has remained undetectable for
the past 2 years.
PMID- 9768957
TI - Extracardiac Fontan operation with tube fenestration allowing transcatheter coil
occlusion.
AB - A fenestration may improve the immediate postoperative course after a Fontan
procedure by preserving the cardiac output. We describe a simple and safe
technique of fenestration amenable to coil occlusion, which can be carried out in
most cardiac catheterization laboratories.
PMID- 9768958
TI - Absent aortic valve: successful palliation in the neonate.
AB - A successful palliation of a neonate with absent aortic valve in hypoplastic left
heart syndrome is reported.
PMID- 9768959
TI - Successful repair of aortoesophageal fistula secondary to traumatic
pseudoaneurysm.
AB - There have previously been only rare reported survivors of an aortoesophageal
fistula resulting from a traumatic pseudoaneurysm. We report a case of a young
man with a dramatic presentation who was successfully managed by immediate
operative repair. A prosthetic graft was sewn within the sac of the aneurysm,
with the aneurysm wall being used to protect the graft, and the esophagus was
resected. Staged reconstruction of the esophagus was subsequently performed
successfully. The patient is now alive and well 2 1/2 years later.
PMID- 9768960
TI - Surgical retrieval of an embolized central venous catheter in a premature baby.
AB - Embolization of central venous catheter fragments is usually treated with
percutaneous interventional techniques, which are difficult to apply in infants
with very low birth weight. We surgically removed a catheter fragment in a
preterm neonate, to avoid the impending thrombosis of the right pulmonary artery.
The operation was performed with a nerve hook introduced through a tiny incision
in the vessel's wall. The procedure was well tolerated, and no stricture remains
at the site of incision.
PMID- 9768961
TI - Tracheal obstruction in achalasia: a role for airway stenting?
AB - We describe an 82-year-old woman who presented with acute tracheal obstruction
secondary to advanced, asymptomatic achalasia. Conventional treatment of her
achalasia failed to relieve recurrent episodes of airway obstruction requiring
endotracheal intubation. Because she was not fit for an operation, a Gianturco
endotracheal stent was placed bronchoscopically. She remains without respiratory
or upper gastrointestinal symptoms 2 years later. Recent information regarding
the pathophysiology and surgical treatment of this complication is reviewed.
PMID- 9768962
TI - A taste of Chinese medicine!
AB - We report a case of profound anticoagulation caused by interaction between
warfarin and danshen, a widely used Chinese herbal medicine, in a patient who had
undergone mitral valve replacement. Patients taking warfarin should be warned not
to take this herb. In addition, physicians should be alert to the possibility of
an interaction with herbal medicine when anticoagulation control becomes
difficult and no other causes are apparent.
PMID- 9768963
TI - Double-outlet right ventricle with complete atrioventricular canal.
AB - A case of double-outlet right ventricle, unbalanced complete atrioventricular
canal, hypoplastic aortic arch, coarctation of the aorta, and atrioventricular
valve regurgitation was treated with a staged approach. At 4 days of life the
patient underwent aortic arch repair, atrial septectomy, common atrioventricular
valve regurgitation repair, and pulmonary artery banding. When she was 14 months
of age a biventricular repair was accomplished by two-patch complete
atrioventricular canal repair and arterial switch procedure.
PMID- 9768964
TI - Surgical resection of lung cancer originating in a tracheal bronchus.
AB - We experienced a case of lung cancer that developed from a tracheal bronchus in
an 80-year-old man. The tumor was completely resected by right upper lobectomy
and resection of the tracheal bronchus as well as dissection of the mediastinal
lymph nodes. Postsurgical pathologic staging was stage IB (T2 N0 M0)
adenocarcinoma.
PMID- 9768965
TI - Surgical management of superior vena caval syndrome in sarcoidosis.
AB - Sarcoidosis causing the superior vena caval syndrome has been only rarely
documented in the literature. We report surgical management of this problem with
a spiral vein graft.
PMID- 9768966
TI - Inflammatory pseudotumors of the lung.
AB - Two unusual cases of inflammatory pseudotumors in young female patients are
described. One presented with massive hemoptysis and a solitary circumscribed
mass treated with urgent lobectomy. The second presented initially with cough and
a small right lower lobe mass. She presented again, 8 years later, with a lung
mass so expanded as to necessitate a pneumonectomy with partial resection of
surrounding structures. Both cases indicate the need for early and complete
removal of the inflammatory pseudotumors.
PMID- 9768967
TI - Purposeful delay in the repair of a traumatic rupture of the aorta with
coexistent liver injury.
AB - Purposeful delay in the repair of traumatic aortic injury by appropriate medical
management is indicated when the risk of immediate thoracotomy is high. A grade V
liver injury implies parenchymal disruption of greater than 75% of a hepatic
lobe. We report the successful management of a patient with a class IB proximal
descending aortic transection and concomitant grade V liver injury that precluded
aortic repair until its resolution.
PMID- 9768968
TI - Tophaceous pseudogout of the mitral valve.
AB - This report describes a 61-year-old patient on chronic hemodialysis with
multiple, left-sided, intracardiac masses causing intermittent coronary
obstruction. Mitral valve replacement was performed. Massive deposition of
calcium pyrophosphate crystals in and around the valve cusps led to the diagnosis
of tophaceous pseudogout (tumoral calcinosis) of the mitral valve.
PMID- 9768969
TI - Cardiomyoplasty after implantation of a pacemaker and cardioverter/defibrillator.
AB - Presently, a combination of two surgical methods improves the survival of
patients with advanced ventricular dysfunction: implantable
cardioverter/defibrillator implantation (which prevents sudden cardiac death) and
cardiomyoplasty (which prevents further dilatation of the heart and provides
additional cardiac assistance). We report the clinical course of a patient who
had cardiomyoplasty after cardioverter/defibrillator implantation and pacemaker
insertion. It is a rare case in which three different devices
cardioverter/defibrillator, pacemaker, and cardiomyostimulator) are functioning
together without crosstalk.
PMID- 9768970
TI - Reversible snaring for proper prosthetic seating during valve replacement.
AB - A method of reversible suture snaring is described for evaluating the final valve
seating and positioning before knot tying of valve sutures. This allows for
alteration of the operative plan before investing substantial ischemic time in a
nonfunctional result. The procedure has been used in 577 consecutive prosthetic
valve replacements in the past 5 years. The technique maintains proper seating
while the valve is permanently anchored in place.
PMID- 9768971
TI - Advancement flaps to treat superficial wound infections after cardiac operations.
AB - The management of superficial sternal wound infections is not well-codified. In
case of large necrosis or tissue defect we use a two-stage approach, consisting
of a first surgical debridement, followed a few days later by wound closure by
means of two lateral advancement flaps. We have used this technique with good
cosmetic results and shorter hospital stays.
PMID- 9768972
TI - Hybrid-type stabilizer for off-pump direct coronary artery bypass grafting.
AB - We have developed a mechanical stabilizer for use in off-pump direct coronary
artery bypass grafting. We consider it an improvement on the sucker-type
stabilizer, although it uses the mechanisms of the compressor-type. Our hybrid
stabilizer effectively immobilizes the local heart surface with light compression
and low evacuation. We believe that its use will eliminate the need for further
immobilization and thus reduce cardiac invasiveness.
PMID- 9768973
TI - Improved visualization in minimally invasive coronary bypass grafting.
AB - A special surgical technique is required for minimally invasive coronary artery
bypass grafting, particularly under beating-heart conditions. We describe a very
simple system that provides improved visualization of the surgical site.
PMID- 9768974
TI - Counteracting paradoxical motion in videoendoscopic operations.
AB - Paradoxical motion during videoendoscopic operations is generated when the camera
and instruments are on opposite sides of the targeted pathology. This is
occasionally difficult to avoid when operating on a wide field. We have found
that turning the camera 180 degrees restores the normal spatial relationship.
This simple maneuver allows the operator to use the existing camera and
instrument ports to his or her best ergonomic advantage.
PMID- 9768975
TI - Accurate length adjustment of aortocoronary saphenous vein bypass grafts.
AB - We describe a simple method for tailoring the length of aortocoronary saphenous
vein grafts. The objective is to prevent any kinking of the these grafts, which
may compromise blood flow in them and lead to their early occlusion.
PMID- 9768976
TI - Coronary artery bypass grafting in patients with cerebrovascular disease.
AB - The incidence of carotid artery disease in patients undergoing coronary artery
bypass grafting appears to be increasing as our population ages. The optimal
treatment for these high-risk patients with concomitant carotid and coronary
artery disease remains controversial. This review focuses on the management of
patients with coexistent carotid and coronary arteriosclerosis. The significance
and management of the patient with an asymptomatic carotid stenosis in patients
undergoing coronary artery bypass grafting and the role of combined coronary
artery bypass grafting and carotid endarterectomy in these patients will be
discussed.
PMID- 9768977
TI - Circulatory support devices for bridge to recovery.
PMID- 9768978
TI - As originally published in 1992: Skeletal muscle ventricles in the pulmonary
circulation: up to 16 weeks' experience. Updated in 1998.
PMID- 9768979
TI - Severe truncal valve dysplasia: association with DiGeorge syndrome?
PMID- 9768980
TI - What is "minimally invasive"?
PMID- 9768981
TI - Severe postoperative hemorrhage after neoadjuvant chemotherapy for invasive
thymoma.
PMID- 9768982
TI - Angioscopic pulmonary embolectomy and ECMO.
PMID- 9768983
TI - Omental transplantation for vascular myelopathy caused by an aortic operation.
PMID- 9768984
TI - Why aren't valve sizers and prostheses labeled accurately?
PMID- 9768985
TI - How high should mammary artery be harvested for the minimally invasive approach?
PMID- 9768986
TI - Retrograde autologous priming reduces blood use.
PMID- 9768987
TI - Surgical procedure for bilateral lung and liver hydatid cysts.
PMID- 9768988
TI - Repeated pulmonary metastasectomy.
PMID- 9768989
TI - The LAST operation: techniques and results before and after the stabilization
era.
AB - BACKGROUND: Left anterior descending artery stabilization allows performance of
left internal mammary artery grafting via a left anterior small thoracotomy on a
beating heart. Our surgical experience was reviewed to assess if surgical results
have improved as result of specialized instrumentation. METHODS: Of 545 patients
who had the left anterior small thoracotomy operation, 261 underwent this
procedure for single left anterior descending artery disease. Two groups were
considered, before and after the use of specialized instrumentation: group A (n =
93), operated on from November 21, 1994, to April 20, 1996; and group B (n =
168), operated on from April 21, 1996, to December 1997. RESULTS: Early mortality
was similar in the two groups. The further revascularization (operation or
percutaneous transluminal coronary angioplasty) and the rate of occlusion of the
conduit were higher in group A, whereas anastomotic or conduit malfunction was
not. Cumulating angiography and Doppler flow evaluation, 92.5% of the anastomoses
in group A and 98.8% in group B (p = 0.026) were patent, and 90.3% in group A and
97.6% in group B (p = 0.031) were patent and not restrictive. At 19 months,
survival was similar, but the event-free survival was higher in group B.
CONCLUSIONS: Both left anterior descending artery stabilization and safer left
internal mammary artery harvesting contributed to improve angiographic and
clinical results after the left anterior small thoracotomy operation.
PMID- 9768990
TI - Safety and cost-effectiveness of MIDCABG in high-risk CABG patients.
AB - BACKGROUND: Myocardial revascularization without cardiopulmonary bypass has been
proposed as a potential therapeutic alternative in high-risk patients undergoing
coronary artery bypass grafting. To evaluate this possibility we compared 15 high
risk (HR) patients in whom minimally invasive direct coronary artery bypass
grafting was used as the method of revascularization with 41 consecutive patients
who underwent conventional coronary artery bypass grafting during 1 month.
METHODS: Patients undergoing myocardial revascularization without cardiopulmonary
bypass were significantly older than their low-risk (LR) counterparts (72.2 +/-
11.6 versus 63.3 +/- 9.7 years, p = 0.006). The demographic profile for HR versus
LR patients was as follows: female patients, 60.0% versus 26.8%, p = 0.02;
diabetes, 20.0% versus 24.4%, p = 0.7; prior stroke, 33.3% versus 7.4%, p = 0.03;
chronic obstructive pulmonary disease, 60.0% versus 9.8%, p < 0.0001; peripheral
vascular disease, 33.3% versus 12.2%, p = 0.03, congestive heart failure, 26.6%
versus 9.8%, p = 0.09; impaired left ventricular (ejection fraction < 0.40),
40.0% versus 17.0%, p = 0.07; urgent operation, 86.6% versus 46.3%, p < 0.0001;
and redo operation, 20.0% versus 0%, p = 0.003. RESULTS: There were no deaths in
the HR group and one death in the LR group. The average intensive care unit stay
was 1.1 +/- 0.5 days in HR patients versus 1.6 +/- 1.6 days in LR individuals (p
= 0.2), and the average hospital stay was 6.1 +/- 1.8 versus 7.3 +/- 4.4 days,
respectively (p = 0.3). We used an acuity risk score index developed by the Adult
Cardiac Care Network of Ontario to predict outcome in the HR group. The expected
intensive care unit stay in HR patients was 4.1 +/- 1.2 days (versus the observed
stay of 1.1 +/- 0.5 days, p < 0.0001), and the expected hospital stay was 12.5 +/
1.5 days (versus the observed stay of 6.1 +/- 1.8 days, p < 0.0001). The
expected mortality in the HR group was 6.1% versus 0%, p = 0.3. A cost regression
model was used to examine predicted versus actual cost (in Canadian dollars) for
the HR patient cohort (based on Ontario Ministry of Health funding). The expected
cost for the HR cohort would have been $11,997 per patient. In contrast, the
average cost for these 15 patients was $5,997 per patient, an estimated cost
saving of 50%. CONCLUSIONS: Myocardial revascularization without cardiopulmonary
bypass appears to be a safe and cost-effective therapeutic modality for HR
patients requiring myocardial revascularization.
PMID- 9768991
TI - Left anterior descending coronary artery bypass grafting through minimal
thoracotomy.
AB - BACKGROUND: In recent years, minimally invasive direct coronary artery bypass
grafting has emerged as a valid tool for revascularization in a select group of
patients with severe lesions of the left anterior descending coronary artery.
Here we report the clinical results using two devices designed by us to
facilitate the harvesting of the left internal mammary artery up to its origin
and to occlude and stabilize the left anterior descending coronary artery while
placing the anastomosis. METHODS: From January 1996 to January 1998, 122 patients
underwent minimally invasive direct coronary artery bypass grafting in the
Department of Cardiac Surgery, Favaloro Foundation. One hundred twelve patients
received a single left internal mammary artery-left anterior descending coronary
artery bypass graft, and in 10 patients, an additional bypass graft was
performed. RESULTS: Most patients were discharged on day 2 or 3 after the
procedure. Three patients (2.5%) had a perioperative myocardial infarction. The
overall hospital mortality rate was 3.3% (4 patients). CONCLUSIONS: The
combination of team experience, more careful dissection of the left internal
mammary artery up to its origin, and use of the stabilizer-occluder and
interrupted suture technique for the anastomosis has markedly improved our
results.
PMID- 9768992
TI - Thoracoscopic harvest of the internal thoracic artery: a multicenter experience
in 218 cases.
AB - BACKGROUND: Off-pump bypass grafting most commonly involves harvest of the left
internal thoracic artery (ITA) through a minithoracotomy under direct vision.
Disadvantages to this approach, however, include poor exposure, incomplete
dissection resulting in inadequate ITA length, and significant postoperative pain
because of rigorous chest retraction. This study determined the safety and
efficacy of an alternative to direct ITA harvest using a thoracoscopic approach.
METHODS: Two hundred eighteen patients at three institutions underwent
thoracoscopic ITA harvest; 118 (54%) for off-pump coronary bypass grafting.
RESULTS: The left ITA was harvested in 211 patients (96%); the mean harvest time
ranged from 42 to 55 minutes. The ITA was injured in 4 patients (1.8%), and
conversion to open ITA harvest occurred in 18 (8%). Complications included
intercostal neuropathy (4), reoperation for ITA bleeding (2), phrenic nerve
injury (1), and wound infection (1). CONCLUSIONS: This large, multicenter
experience demonstrates that thoracoscopic harvest of the ITA can be accomplished
safely and within a reasonable time frame in most patients undergoing coronary
bypass grafting.
PMID- 9768993
TI - Minimally invasive surgical treatment of coronary artery multivessel disease.
AB - BACKGROUND: If coronary artery multivessel disease is the target of a minimally
invasive procedure, either median sternotomy or cardiopulmonary bypass can be
avoided. METHODS: We used an alternate technique instead of minithoracotomy and
cardiopulmonary bypass to treat 102 patients (82 men, 20 women; age range, 39 to
82 years; median, 61.0 +/- 8.9 years) for coronary artery single-vessel, double
vessel, or multivessel disease between November 1996 and January 1998. Twenty
nine patients (22 men, 7 women; age range, 46 to 78 years; median, 69.0 +/- 8.4
years), who were in a high-risk group for the development of perioperative
complications because of the use of cardiopulmonary bypass, received median
sternotomy and a beating heart procedure using the Octopus stabilizing technique.
The left anterior descending coronary artery was the target vessel in all
patients except for 1, in whom the left internal mammary artery was used.
RESULTS: There was no intraoperative death in either series. In the beating heart
group (Octopus) 2 patients died on postoperative day 31 and 35, respectively, of
postoperative pneumonia. CONCLUSIONS: Both techniques present safe alternative
procedures to conventional coronary artery bypass grafting in patients with
coronary artery multivessel disease.
PMID- 9768994
TI - Minimally invasive coronary artery bypass grafting without cardiopulmonary
bypass: early experience and follow-up.
AB - BACKGROUND: There is renewed interest in coronary artery bypass grafting without
cardiopulmonary bypass using the anterolateral minithoracotomy approach. We
evaluated 209 patients who underwent minimally invasive direct coronary artery
bypass grafting using an anterolateral minithoracotomy. The anastomosis was
performed under direct vision on the beating heart without using cardiopulmonary
bypass. METHODS: The procedure was performed using a 6- to 9-cm left (or right)
anterolateral thoracotomy for internal thoracic artery graft harvesting and
anastomosis. Different devices were used for local immobilization. In 195
patients a single internal thoracic artery to left anterior descending coronary
artery bypass was performed, in 3 patients a single right internal thoracic
artery to right coronary artery bypass, and in 11 patients the radial artery was
used together with the internal thoracic artery as a T-graft. RESULTS: Conversion
to sternotomy or cardiopulmonary bypass was necessary in 10 (4.7%) patients.
Intraoperative myocardial infarction was observed in 4 patients (1.9%). Early
postoperative redo operation was necessary in 5 patients (2.4%). Mortality was
0.47%. Postoperatively, 191 patients (91.3%) underwent angiography for graft
patency control. The overall patency rate was 97.3%. Minor stenosis of the
internal thoracic artery graft was observed in 18 patients (9.4%); moderate
stenosis was observed in 5 patients (2.6%). Midterm angiographic follow-up after
6 months was performed in 58 patients. The patency rate was 98.2%. One patient
with severe symptomatic stenosis (1.7%) underwent reoperation. CONCLUSIONS: With
the help of the local immobilization systems off-pump coronary artery bypass
grafting was safely performed through a minithoracotomy. The incidence of
intraoperative and postoperative complications was low and follow-up showed good
results. Thus, minimally invasive direct coronary artery bypass grafting is an
excellent technique for arterial revascularization in patients having symptomatic
left anterior descending coronary artery disease.
PMID- 9768995
TI - Minimally invasive saphenous vein harvesting.
AB - BACKGROUND: Minimally invasive techniques to harvest the saphenous vein for
coronary artery bypass grafting continue to improve and evolve. Smaller cutaneous
incisions have been shown to decrease postoperative discomfort and improve
healing. We describe a technique involving carbon dioxide insufflation and
endoscopic dissection to allow easier and atraumatic dissection. METHODS: The
VasoView endoscope system (Origin Medsystems, Inc) was used to harvest the
saphenous vein for coronary artery bypass grafting in 27 patients. This group was
compared with 24 patients having traditional saphenous vein harvesting. Wounds
were examined for complications daily. Pain and postoperative mobility were
quantified independently by physical therapists. RESULTS: Comparison of patients
in the two groups revealed greater edema in the legs with traditional harvesting.
Patients with endoscopic removal also had less pain and increased mobility
postoperatively. On average, minimally invasive harvesting allowed patients to
ambulate to a predischarge goal of 300 ft 2 days earlier. CONCLUSIONS: Minimally
invasive harvesting of the saphenous vein by insufflation techniques is safe,
effective, and atraumatic to the conduit. Discomfort is minimized, promoting
earlier and improved ambulation.
PMID- 9768996
TI - Feasibility study of a mechanical suturing device for less invasive mitral
operations.
AB - BACKGROUND: Because of smaller incisions and limited exposure, less invasive
operations on the mitral valve can be arduous and time-consuming. This study
examined the feasibility of a mechanical suturing device to facilitate less
invasive mitral replacement. METHODS: Five mongrel dogs underwent limited left
thoracotomy. After conventional cardiopulmonary bypass and cardioplegia, the
mitral valve was exposed through a left atriotomy. After excision of the anterior
leaflet, subannular sutures were placed using a mechanical suturing device. This
device simultaneously passes two ends of a pledgeted 2-0 braided suture through
the valvular annulus, then mechanically grasps both needles on the atrial aspect.
Hence, a mattress suture is accomplished one-handed in a single continuous
motion. This procedure was repeated around the entire annulus. A mechanical valve
was seated and the sutures were tied and cut. RESULTS: All mechanical valves were
implanted successfully. In the 4 animals in which it was attempted,
cardiopulmonary bypass was successfully weaned. No evidence of perivalvular leak
was observed by echocardiography. CONCLUSIONS: These data establish the
feasibility of a mechanical suturing device for operations on the mitral valve.
The device is easily mastered, maintains precise spacing between sutures, and
permits rapid placement of mattress sutures. We predict widespread application
for both less invasive and conventional valve operations.
PMID- 9768997
TI - Coronary artery bypass on the beating heart with the Octopus: a North American
experience.
AB - BACKGROUND: The practice of minimally invasive coronary artery bypass grafting
remains controversial. This study outlines the results of single and multiple
vessel bypass performed using the Medtronic Octopus Tissue Stabilization System
and beating heart techniques. Results are compared with those of a standard
cardiopulmonary bypass group. METHODS: The group included 89 patients having
operations performed during a 10-month period with average follow-up of 162.3
days. Complications, length of stay, and functional status were recorded.
Postoperative stress testing and angiograms were performed selectively. RESULTS:
The average age was 62.3 years and the average ejection fraction was 0.65. Twenty
five percent of the patients underwent operations urgently or emergently,
averaging 1.8 grafts/patient. In 83 of 89 patients operations were completed
without cardiopulmonary bypass using the Octopus without mortality. Morbidities
were statistically similar to a group of 369 cardiopulmonary bypass patients.
Postoperative length of stay was shorter in the Octopus group (p = 0.005).
CONCLUSIONS: The Octopus provided predictable, reproducible immobilization with
short-term results comparable with those obtained with standard cardiopulmonary
bypass.
PMID- 9768999
TI - Facilitated vascular anastomoses: the one-shot device.
AB - BACKGROUND: A mechanical system for facilitating vascular anastomosis (end-to
side, end-to-end) is described that enables the rapid construction of
nonpenetrated, compliant junctions. The instrument (United States Surgical One
Shot system) simultaneously applies either 10 or 12 nonpenetrating, arcuate
legged titanium clips to everted vessel or prosthetic conduit edges. METHODS AND
RESULTS: The instrument has been tested in animals (jugular and femoral vein jump
grafts in carotid and femoral arteries, interpositional grafts, 20 pigs) and
human cadaveric constructs (saphenous veins to left anterior descending coronary
arteries, 20 cases, 5 brachiocephalic access fistulas) as end-to-side constructs.
Clipped constructs have equivalent or superior physical properties to control
sutured constructs (6-0 polypropylene) as gauged by burst and tensile strength.
All studies were performed under Food and Drug Administration Good Laboratory
Practice standards, and the device has been approved for marketing by the Food
and Drug Administration. CONCLUSIONS: The device enables rapid and reproducible
vascular anastomotic constructs with vessels as small as 1.8 mm outer diameter.
The constructs are flanged, interrupted, and nonpenetrated.
PMID- 9768998
TI - Minimally invasive coronary artery bypass grafting: port-access approach versus
off-pump techniques.
AB - BACKGROUND: Within the past 5 years several surgical techniques have been
developed for less invasive surgical treatment of coronary artery disease. The
aim of this study was to define specific indications for the various minimally
invasive coronary artery surgical procedures. METHODS: Minimally invasive direct
coronary artery bypass grafting through a minithoracotomy was performed in 67
patients. The left internal mammary artery was anastomosed on the beating heart
with the use of a pressure or suction stabilizer without the use of
extracorporeal circulation. In 58 other patients with multivessel disease, the
off-pump coronary artery bypass grafting technique through a sternotomy was
applied with a left internal mammary artery to left anterior descending artery
and additional vein grafts without extracorporeal circulation. In a third group,
Port-Access (Heartport Inc, Redwood City, CA) coronary artery bypass grafting was
performed through a left minithoracotomy with the use of an endovascular
extracorporeal circulation system and cardioplegic arrest. Angiographic follow-up
was complete in 64% of the patients. RESULTS: There was minimal perioperative or
postoperative mortality (0.5%). The medium surgical procedure time for all
minimally invasive and off-pump procedures was 2.5 hours; it was 4.5 hours for
Port-Access procedures. The median postoperative intensive care unit stay was 1.0
days, and the median hospitalization was 5.0 days. Overall graft patency was
97.3%; in 8 patients (4.1%) a stenosis either at or distal to the graft
anastomosis was dilated with coronary angioplasty. CONCLUSIONS: For single-vessel
disease of the left anterior descending artery, the minimally invasive coronary
artery bypass grafting procedure can be performed safely without the use of
extracorporeal circulation. In case of hemodynamic instability or anatomic
variation, the Port-Access procedure can be applied without additional necessity
for sternotomy. For multivessel disease, the off-pump bypass grafting procedure
with sternotomy can be recommended depending on the coronary arteries involved.
In case of necessary grafts to the lateral marginal or circumflex branches, Port
Access grafting can be recommended and may play an important role in the future
for the development of fully endoscopic robot-assisted coronary artery bypass
grafting.
PMID- 9769000
TI - Beyond stents: third-generation coronary devices.
AB - Despite extraordinary growth in percutaneous transluminal coronary angioplasty
(>400,000 cases in United States in 1997) patients are still routinely referred
for bypass grafting in large numbers. Why? Second-generation devices (directional
coronary atherectomy, high-speed rotational atherectomy [Rotablator], and stents)
have expanded the application of percutaneous catheter treatment of coronary
disease. Specifically, highly eccentric lesions in large vessels, heavily
calcified lesions, and coronary dissections can be effectively treated with these
devices. Stents have substantially reduced the incidence of restenosis, but this
benefit is largely confined to vessels more than 3 mm in diameter and stenoses
less than 20 mm in length. A third generation of coronary devices has evolved in
the late 1990s in response to continuing failures of conventional balloon
angioplasty, atherectomy, and stenting. The failures of the 1990s were (1)
restenosis, including in-stent restenosis, (2) chronic total occlusions, (3)
diffuse small-vessel disease, and (4) aged vein graft disease. In response to
these challenges novel devices are being developed: (1) for restenosis,
intracoronary radiation therapy (brachytherapy); (2) for chronic total
occlusions, Prima Laser wire; (3) for diffuse small-vessel disease, percutaneous
myocardial laser revascularization; and (4) for aged vein grafts,
antiembolization devices. Each of these new catheter technologies will need to be
economically and clinically reconciled with the multitude of minimally invasive
surgical revascularization techniques that are rapidly evolving.
PMID- 9769001
TI - Less invasive cardiac operations through a median sternotomy: 100 consecutive
cases.
AB - BACKGROUND: In the beginning of 1997, we developed a routine approach to
intracardiac operations through a less invasive median sternotomy. A limited (6
to 9 cm) median skin incision followed by a subcomplete (manubrium and body)
median sternotomy makes opening and closing of the chest easier; conventional
central cardiopulmonary bypass is instituted, and no modifications to the
surgical techniques are necessary. METHODS: In 100 consecutive patients (mean
age, 62.04 years; range, 9 to 92 years), 70 aortic, 13 mitral, and 17 other
cardiac procedures were performed. Surgical technique required many self-made
instruments; anesthetic "fast-tracking" management was performed. RESULTS: Four
patients died. One conversion to a standard sternotomy and five reoperations for
bleeding were necessary. Cross-clamp time ranged from 33 to 140 minutes (mean +/-
standard deviation, 69.23 +/- 20.99 minutes) and total drainage loss ranged from
120 to 1,800 mL x m(-2) x 24 h(-1) (mean, 288 mL x m(-2) x 24 h(-1)). The
postoperative course was shorter than usual, and one complication in the healing
wound was observed. The scar was shorter than 9 cm in all patients. CONCLUSIONS:
Our work shows that a less invasive approach to many cardiac operations is
possible through a modified median sternotomy. This technique provides many
potential and practical advantages: there is less trauma and pain reported by
patients, and the small wound reduces the risk of infection and blood loss.
Patients are extubated and discharged from the hospital earlier.
PMID- 9769002
TI - Arterial graft patency in coronary artery bypass grafting: what do we really
know?
AB - BACKGROUND: With increasing use of beating heart techniques for bypass of the
left anterior descending coronary artery with the left internal mammary artery
(LIMA), appropriate concerns have been raised of whether graft patency by these
techniques compares favorably with conventional, arrested heart techniques.
METHODS: All published articles that examine outcome efficacy of the LIMA graft
to the left anterior descending coronary artery were reviewed. Because
angiography has been considered the "gold standard," only those studies that
included angiographic follow-up were analyzed. RESULTS: From 1972 through 1998,
there have been 37 peer-reviewed publications that examined outcomes of LIMA
grafting in conventional coronary bypass grafting, of which 27 contained
angiographic follow-up data. The completeness of angiographic follow-up was
variable, but early graft patency (< or =1 month) in studied patients ranged
between 94% and 99%. Late graft patency (up to 15 years) ranged from 51% to 98%.
Five recent series of minimally invasive direct coronary artery bypass grafting
that contained LIMA graft patency data show early graft patency rates between 91%
and 99%. CONCLUSIONS: Meaningful comparison of LIMA graft patency between
arrested heart, conventional coronary artery bypass grafting, and minimally
invasive direct coronary artery bypass grafting is difficult; however, early
graft patency by both techniques can confidently be stated as being 90% or
greater.
PMID- 9769003
TI - Computer-assisted telemanipulation: an enabling technology for endoscopic
coronary artery bypass.
AB - BACKGROUND: The ultimate objective of minimally invasive coronary artery bypass
grafting is to perform the anastomosis totally endoscopically. In this
feasibility study, we examined the potential of performing coronary artery bypass
grafting with the use of computer-assisted telemanipulation technology. METHODS:
Intuitive Telemanipulation Technology (Intuitive Surgical, Mountain View, CA) was
used to perform an arterial graft to left anterior descending coronary artery
anastomosis in an ex vivo on-bench swine heart model. The degree of difficulty in
performing the anastomosis, intraoperative events, duration of the anastomosis,
and its quality were determined. RESULTS: Anastomosis was performed with relative
facility, in a range of 10.7 to 17.4 minutes (mean +/- standard deviation, 14.6
+/- 2.6 minutes). All anastomoses were patent and of good quality except one,
which had 30% narrowing of its heel. CONCLUSIONS: We conclude that Intuitive
Telemanipulation Technology may in the future permit the performance of quality
totally endoscopic coronary artery anastomosis with facility and acceptable time.
PMID- 9769004
TI - Robotically assisted microsurgery for endoscopic coronary artery bypass grafting.
AB - BACKGROUND: As minimally invasive approaches to cardiac surgery have expanded, a
significant number of limitations have become apparent, particularly the lack of
adequate precision with standard endoscopic instruments. We hypothesized that the
use of robotics would eliminate some of these limitations. METHODS: Twenty-five
coronary anastomoses on an isolated porcine heart, using an arterial conduit to
the left anterior descending artery, were performed endoscopically with a
microsurgical robotic system. Sophisticated robotic engineering was used to
control modified endoscopic instruments under direct surgeon control. Computer
tremor elimination and motion scaling allowed for precise maneuvering. An
arteriotomy was placed in the left anterior descending artery, and an arterial
conduit was positioned for anastomosis. The camera and port sites were placed 90
degrees from the long axis of the arteriotomy. A 7-0 Prolene (Ethicon,
Somerville, NJ) suture was used to perform the anastomosis in a continuous
fashion, begun at the 12 o'clock position and continued counterclockwise. After
completion of half of the anastomosis, the conduits were pulled down and the
final sutures were placed. The sutures were tied intracorporeally and the
procedure was completed. RESULTS: The 25 conduits were successfully completed and
showed good probe patency. Average time for completion of the anastomosis was
31.7 +/- 2.0 minutes. Appropriate port placement and orientation, and
stabilization of the conduits were critical. The lack of tremor and motion
scaling allowed for the precise movements needed to complete an endoscopic
microvascular anastomosis. CONCLUSIONS: Coronary artery anastomoses are
technically feasible with use of robotic instrumentation. This technology may
enable the development of a truly endoscopic approach to bypass surgery.
PMID- 9769006
TI - Minimally invasive coronary revascularization in elderly patients.
AB - BACKGROUND: Internal mammary artery to left anterior descending coronary artery
anastomosis can be done without extracorporeal circulation on the beating heart.
This method seems to have particular advantages for elderly patients, those 70
years old or older. METHODS: From January 1, 1997, to October 31, 1997, 27
patients have been operated on with a minimally invasive approach through a left
sided minithoracotomy. Twelve patients had up to four previous percutaneous
interventions with percutaneous transluminal coronary angioplasty (3) or
percutaneous transluminal coronary angioplasty and stent implantation (9). The
remainder showed stenosis not suitable for percutaneous transluminal coronary
angioplasty or an occluded vessel. In all patients the internal mammary artery
was anastomosed with the left anterior descending coronary artery, and in 2
patients additionally with the first diagonal. In 1 patient the operation had to
be converted to a sternotomy because it was impossible to identify the left
anterior descending coronary artery. RESULTS: All patients survived the
operation. There was no perioperative infarction. All patients were extubated
within 4 hours. Mean stay in the intensive care unit was 20.3 hours;
postoperative stay was 7.4 days. Nine patients had elective repeat angiography
within 10 days postoperatively and all showed a patent graft. CONCLUSIONS: We
believe that minimally invasive coronary revascularization of the anterior wall
can be done in elderly patients with low risk and good results.
PMID- 9769005
TI - Off-pump multivessel coronary bypass via sternotomy is safe and effective.
AB - BACKGROUND: In an attempt to avoid the deleterious effects of cardiopulmonary
bypass, off-pump coronary artery bypass grafting has been rediscovered and
refined. The purpose of this study was to compare clinical outcomes, length of
stay, and hospital costs with coronary artery bypass grafting on cardiopulmonary
bypass. METHODS: Coronary artery bypass was performed on 51 patients without
cardiopulmonary bypass. Patients were selected on the basis of coronary anatomy,
with significant stenoses in the left anterior descending, ramus intermedius,
diagonal, right coronary, acute marginal, or posterior descending territories.
Outcomes were compared with those of a computer-generated matched control group
having coronary artery bypass grafting on cardiopulmonary bypass (n = 248) during
the same time period. RESULTS: No preoperative differences were noted between
groups. There were no deaths in the off-pump group and a mortality rate of 1.6%
(4/248) in the control group. There was no incidence of stroke, myocardial
infarction, or reentry for bleeding among patients in the off-pump group. There
was a reduction in length of stay by 3 days (p = 0.01), blood transfusions by 50%
(p = 0.0001), and hospital charges by one third (p = 0.05) in the off-pump group.
Twenty-six patients had repeat coronary angiography before discharge; 41/43
grafts were widely patent, 1/43 was totally occluded, and 1/43 was narrowed by
more than 50%. All internal mammary artery grafts were widely patent.
CONCLUSIONS: Off-pump multivessel cardiopulmonary bypass grafting is a safe and
effective means of revascularization for patients with coronary stenoses in the
anterior or inferior regions, with excellent short-term patency rates and minimal
morbidity.
PMID- 9769007
TI - Beating heart operations including hybrid revascularization: initial experiences.
AB - BACKGROUND: The outcome of patients (n = 45) with coronary one- to three-vessel
disease undergoing beating heart operations using a recently developed
stabilizing device was investigated. METHODS: Left internal mammary artery-to
left anterior descending coronary artery (LIMA-to-LAD) revascularization was
carried out alone (n = 31) or as hybrid procedure in combination with a balloon
angioplasty (n = 14). RESULTS: All 45 patients underwent a successful LIMA-to-LAD
procedure without intraoperative complication during a 21 +/- 8-minute (range, 10
to 53 minutes) LAD occlusion time. In 14 hybrid procedures a total of 19 stenoses
including 3 left main stenoses were treated successfully by percutaneous
transluminal coronary angioplasty and stenting. The postoperative courses were
uneventful with the exception of two surgical reexplorations necessitated by
bleeding. No worsening of renal, neurologic, or respiratory functions occurred in
any patient. In the group having a single LIMA-to-LAD procedure, early
postoperative coronary angiograms (22 of 31) showed a patent LIMA graft and
excellent anastomosis; this was also true in 4 patients 12 months after operation
as shown in angiograms. All patients undergoing hybrid revascularization
demonstrated a patent LIMA-to-LAD anastomosis; in 1 patient there was a
dissection in the midlevel of the LIMA, which was stented successfully. The 6
month follow-up angiograms in 7 of 14 patients revealed open LIMA bypass grafts
in all patients except 1, who was stented because of dissection. CONCLUSIONS:
These data indicate that a beating heart operation including hybrid
revascularization is safe and effective in selected patients with coronary one-
to three-vessel disease including left main stenosis. This approach may be
especially advantageous in comparison with conventional coronary artery bypass
grafting in patients with severe concomitant disease.
PMID- 9769008
TI - Left ventricular geometry and cardiac function during minimally invasive coronary
artery bypass grafting.
AB - BACKGROUND: This investigation was designed to study the changes in function and
geometry of the left ventricle during two critical steps of minimally invasive
direct coronary artery bypass procedures: placement of an epicardial stabilizer
and occlusion of the left anterior descending coronary artery. METHODS: Between
February 1997 and January 1998, 28 patients underwent bypass grafting with the
left internal thoracic artery to the left anterior descending coronary artery
(minimally invasive direct coronary artery bypass technique). Transesophageal
echocardiography was used for determination of fractional area change and to
assess left ventricular (LV) diameters in two dimensions and at the apex.
RESULTS: Placement of the epicardial stabilizer resulted in a small decrease in
LV end-systolic and end-diastolic dimensions; cardiac function remained
unchanged. Subsequent occlusion of the left anterior descending coronary artery
caused a moderate decline in cardiac index and fractional area change, an
increase in LV diameters, and the development of hypokinetic segments within the
LV myocardium. CONCLUSIONS: The use of an epicardial stabilizer provides a safe
and effective means to stabilize the operative field during minimally invasive
direct coronary artery bypass procedures. Monitoring of LV function by
transesophageal echocardiography enhances the safety of such procedures and is
highly recommended.
PMID- 9769009
TI - Role of graft flow measurement technique in anastomotic quality assessment in
minimally invasive CABG.
AB - BACKGROUND: Anastomotic quality is currently the critical issue in minimally
invasive coronary surgery. Although little is known about its effectiveness,
surgeons routinely assess grafts intraoperatively using flow probes. This study
was designed to determine whether mean flow and the pattern of flow tracing in
internal mammary artery grafts obtained with a transit-time flow probe are
reliable indicators of anastomotic quality. METHODS: Mongrel dogs (n = 14, 30 to
35 kg) underwent off-pump left, right, or left and right internal mammary artery
to left anterior descending artery anastomosis (23 grafts). Moderate to severe
degrees of stenosis were created at the anastomosis by an additional suture.
Internal mammary artery graft flow was measured before and after the stenosis was
created with the left anterior descending artery occluded. Angiography was
performed at random postoperatively to validate the degree of stenosis. Mean flow
and flow tracing morphology were compared under various degrees of stenosis.
RESULTS: There were no significant differences in mean graft flow or the
morphology of the flow tracing between patent (<15%), mild (<25%), moderate
(<50%), and moderately severe (<75%) stenosis. However, mean graft flow decreased
(p < 0.05) with severe stenosis (>75%). CONCLUSIONS: Although differences in mean
graft flow and graft flow morphology were detectable in anastomoses with severe
stenosis (>75%), they were indistinguishable in anastomoses with mild (<25%) to
moderately severe (<75%) stenosis. Flow measurement techniques are valuable tools
intraoperatively, but surgeons should exercise caution in their interpretation.
PMID- 9769010
TI - Myocardial damage after minimally invasive coronary artery bypass grafting on the
beating heart.
AB - BACKGROUND: In conventional coronary artery bypass grafting, the rate of
perioperative myocardial infarction is reported in the 2% to 6% range; however,
significantly higher rates are observed if sensitive myocardial marker proteins
are used to detect perioperative myocardial damage. For minimally invasive direct
coronary artery bypass grafting, few data are available concerning myocardial
marker protein release. METHODS: Fifteen consecutive patients (11 male, 4 female;
mean age, 59.6 +/- 8.5 years) received minimally invasive direct coronary artery
bypass grafting procedures via minithoracotomy on the beating heart.
Electrocardiography and transesophageal and transthoracic echocardiography as
well as determination of creatine kinase-MB mass concentration and cardiac
troponin I level were used for ischemic monitoring. RESULTS: One patient had a
perioperative myocardial infarction according to standard criteria and died
despite mechanical circulatory support. Determination of cardiac troponin I level
showed small but definitive ischemic damage in 4 of 9 patients (44%) who
presented transient ischemic signs intraoperatively or postoperatively. In 2 of
these 4 patients pathologic findings could be detected on angiographic restudies.
CONCLUSIONS: Subclinical myocardial injury is a common event in minimally
invasive coronary artery bypass grafting on the beating heart. Cardiac troponin I
could serve as an adequate diagnostic tool for diagnosis of perioperative
myocardial infarction in minimally invasive direct coronary artery bypass
grafting.
PMID- 9769012
TI - Minimally invasive valve surgery versus the conventional approach.
AB - As a result of reports touting the effectiveness of minimally invasive valve
operations, many cardiovascular surgeons and their patients are beginning to
believe that smaller incisions are always better. According to its proponents,
the minimally invasive approach results in less pain, a faster recovery, and a
more satisfactory cosmetic result. Proponents also believe that the operation can
be done safely and effectively at a lower cost than traditional surgical
approaches. This may not be the case, however, and additional prospective studies
must be done before firm conclusions can be drawn. For example, cardiopulmonary
bypass, myocardial ischemia, and overall operative times are significantly longer
(40% or more) for minimally invasive surgical procedures. Morbidity and mortality
rates do not appear to be decreased, the length of hospital stay varies by only 1
or 2 days, and patients do not necessarily report less postoperative pain. When
the conventional technique is used, the operation can be performed precisely and
expeditiously. Should complications occur, the surgeon will have direct access to
the heart. The cost of a conventional procedure should not be much more than that
of a minimally invasive procedure, and in some instances it may even be less
particularly when the less invasive procedure significantly extends the operating
room time or requires additional monitors or costly disposables.
PMID- 9769011
TI - Transit-time flow measurement for detection of early graft failure during
myocardial revascularization.
AB - BACKGROUND: A low-flow situation in arterial and venous grafts has been
associated with high rates of perioperative infarction and mortality. This study
was designed to look at intraoperative graft flow and resistance in patients with
coronary artery disease. METHODS: Coronary artery bypass graft flow was measured
in 46 patients. Transit-time flow was used for coronary flow measurements at rest
as well as after maximal vasodilation with adenosine infusion. RESULTS: Forty
three of the 46 patients showed normal internal mammary artery graft flow (>20
mL/min); 3 patients had no or minimal graft flow. Redoing the graft anastomosis
in these 3 patients resulted in normalization of graft flow. The mean flow
increased significantly after correction from 0.5 +/- 0.7 mL/min to 15.7 +/- 9.6
mL/min (p < 0.02). Conversely, vascular resistance decreased significantly from
138 +/- 10 to 4.8 +/- 1.8 Ohmv (p < 0.0001), as did the pulsatility index (from
146.9 +/- 95.7 to 3.4 +/- 1.8; p < 0.001). After correction, coronary flow
reserve was 2.5 +/- 1.1. CONCLUSIONS: Measurements of intraoperative flow and
resistance as well as derived variables allow assessment of early graft function
and thus help prevent graft failure and reduce perioperative infarction. Transit
time volume flow might be a simple tool for quality control in coronary bypass
procedures.
PMID- 9769013
TI - Valve operations through a minimally invasive approach.
AB - BACKGROUND: We analyzed in-hospital results of 87 patients undergoing minimally
invasive valvular operations (right parasternal incision through third and fourth
cartilages). METHODS: Age was 21 to 84 years (mean, 56.2 +/- 16); 45 patients
(51.7%) were female. Five (5.7%) had a previous valvular operation and 8 (9.2%)
had severe left ventricular dysfunction. Valve diseases were as follows: aortic
in 35 patients (40.2%), mitral in 44 (50.5%), double in 5 (5.7%), tricuspid
regurgitation in 2 (2.2%), and mitral periprosthetic leak in 1 (1.1%). RESULTS:
Nineteen mitral repairs (21.9%), 22 replacements (25.3%), 1 leak closure (1.1%),
1 tricuspid repair (1.1%), and 1 replacement (1.1%) were performed. Thirty-one
patients (35.7%) underwent aortic replacement, 2 (2.3%) aortic decalcification, 1
(1.1%) subaortic membrane resection, 4 (4.6%) a double-valve procedure, and 5
(5.7%) a single-valve operation combined with myocardial revascularization. In
hospital mortality was 5.7% (5 patients). Univariate analysis was significant for
previous operation, New York Heart Association class IV and severe ventricular
dysfunction. Multivariate analysis was significant for previous operation and
severe ventricular dysfunction. Atrial fibrillation (12.6%) was the most frequent
complication. Postoperative stay was 6.5 +/- 6 days. CONCLUSIONS: The minimally
invasive approach is a useful technique in valvular surgery. Patients with a
previous valvular operation, severe ventricular dysfunction, and New York Heart
Association class IV dyspnea have higher in-hospital mortality.
PMID- 9769014
TI - "J" incision minimal-access valve operations.
AB - BACKGROUND: Having used various minimal access incisions in 45 patients and our
approach of "J" incisions, we wished to evaluate results with the latter
incision. METHODS: Between January 1997 and September 1997, 33 consecutive
unselected patients underwent minimal access aortic valve operations (n = 25,
including 4 composite grafts [1 hemiarch, 1 transaortic MVR], 2 root and valve
repairs, and 1 double valve replacement), mitral valve operations (n = 6, 4
repairs, 2 replacements, including 1 maze procedure), or atrial septal defect
repairs through "J" incisions (n = 2). RESULTS: One patient with preoperative
severe pulmonary disease died of adult respiratory distress syndrome (3%, 1/33).
The mean cross-clamp and bypass times were 85.9 minutes and 113.5 minutes,
although for recent isolated aortic valve replacement operations the mean was 44
minutes (range, 39 to 51 minutes). Mean operative blood use was 0.33 units, and
no patient required reoperation for bleeding. The mean time before extubation,
intensive care unit stay, and postoperative stay were 0.44 days, 0.58 days, and
4.8 days. No strokes occurred. Mean postoperative pain medication requirements
were 22.9 mg of morphine and 7.1 oral narcotic doses. CONCLUSIONS: "J" incisions
are safe alternatives to other incisions, result in good exposure, do not require
division of the mammary arteries, minimize postoperative pain medication
requirements, and, with experience, can be performed with acceptable aortic cross
clamp times.
PMID- 9769015
TI - Transmyocardial laser as an adjunct to minimally invasive CABG for complete
myocardial revascularization.
AB - BACKGROUND: To achieve complete myocardial revascularization in patients with
diffuse coronary artery disease and patients at high risk if they undergo
cardiopulmonary bypass such as severe systemic disease or diffuse
arteriosclerosis of the aorta, we have adopted the technique of combining direct
coronary artery bypass grafting without cardiopulmonary bypass with
transmyocardial laser revascularization. METHODS: From April 1995 to September
1997 this technique was used in 77 patients. Ages ranged from 37 to 85 years with
a mean of 56 +/- 17 years. Diffuse coronary artery lesions were present in 46
patients, 10 had severely deranged renal function, 7 had diffuse carotid artery
lesions, and 7 had aortic arch atheromas. Liver dysfunction was present in 4
patients and severe obstructive airway disease in 3. The mean left ventricular
ejection fraction was 0.45 +/- 0.05. Midsternotomy approach was used in 65
patients and anterior minithoracotomy in 12. Direct coronary artery bypass
grafting without cardiopulmonary bypass was done to the left anterior descending
coronary artery or right coronary artery or both. Transmyocardial laser
revascularization using a 1,000-W CO2 laser machine was performed on the areas
supplied by ungraftable coronary arteries or even in graftable distal targets in
the posterolateral or inferior wall in patients who were at high risk if they
underwent cardiopulmonary bypass. RESULTS: The mean number of vessels bypassed
was 1.12. One patient died of intractable ventricular arrhythmia in the early
postoperative phase. Mean follow-up was 16.6 months. At 12 months 89% of the
patients were angina free. Metabolic stress test demonstrated an average increase
in exercise tolerance from 5.2 at baseline to 9.7 minutes at 12 months.
Myocardial thallium scanning done at 3-, 6-, and 12-month intervals
postoperatively revealed that myocardial perfusion in grafted segments had an
exponential trend of improvement, and perfusion in transmyocardial laser
revascularization segments showed a linear trend in the same period with a total
gain of 28.4%. CONCLUSIONS: Transmyocardial laser revascularization is an
excellent adjunct to minimally invasive coronary artery bypass grafting to
achieve complete myocardial revascularization in patients with graftable vessels
in the anterior wall and ungraftable vessels in the posterior and inferior wall.
This achieves complete myocardial revascularization without compromising safety
in patients who are at high risk if they undergo cardiopulmonary bypass. Minimal
morbidity and mortality in the present series revealed that this procedure is
safe, and postoperative follow-up of these patients showed significant functional
improvement as well as an improvement in myocardial perfusion scan.
PMID- 9769016
TI - Should smart operators mix business and surgery?
PMID- 9769017
TI - Liposomes as drug delivery system: a strategic approach for the treatment of HIV
infection.
AB - As the number of individuals infected with human immunodeficiency virus (HIV) is
growing dramatically throughout the world, it is important to develop strategies
to improve the treatment of this deadly disease. It is now well established that
macrophages play a central role in HIV pathogenesis, acting as reservoirs for
dissemination of virus throughout the immune system. As liposomes are naturally
taken up by cells of the mononuclear phagocytic system, liposome-based therapy
represents a convenient approach to improve the delivery of anti-HIV agents into
infected cells improving thereby the efficacy of drugs and reducing their adverse
side-effects. A more specific targeting of HIV-infected cells could also be
obtained by using liposomes bearing surface attached-antibodies. This review
details the applications of liposomes as drug carriers for the treatment of AIDS.
It also gives an overlook of the different strategies that could be explored to
control the progression of the disease in infected individuals.
PMID- 9769018
TI - Efficacy, safety and mechanism of cyclodextrins as absorption enhancers in nasal
delivery of peptide and protein drugs.
AB - Cyclodextrins are used in nasal drug delivery as absorption enhancing compounds
to increase the intranasal bioavailability of peptide and protein drugs. The most
effective cyclodextrins in animal experiments are the methylated derivatives,
dimethyl-beta-cyclodextrin and randomly methylated beta-cyclodextrin, which are
active at low concentrations ranging between 2% and 5%. However, large species
differences between rats, rabbits and humans exist for the nasal absorption
enhancement by cyclodextrins. Based on toxicological studies of the local effects
of cyclodextrins on the nasal mucosa dimethyl-beta-cyclodextrin and randomly
methylated beta-cyclodextrin are considered safe nasal absorption enhancers.
Their effects were quite similar to controls (physiological saline), but smaller
than those of the preservative benzalkonium chloride in histological and ciliary
beat frequency studies. In these studies, and in a study of the release of marker
compounds after nasal administration, methylated beta-cyclodextrins were less
toxic than sodium glycocholate, sodium taurodihydrofusidate, laureth-9 and L
alpha-phosphatidylcholine. Systemic toxicity after nasal cyclodextrin
administration is not expected, because very low doses of cyclodextrins are
administered and only very small amounts are absorbed. The mechanism of action of
cyclodextrins may be explained by their interaction with the nasal epithelial
membranes and their ability to transiently open tight junctions.
PMID- 9769019
TI - Molecular weight-dependent paracellular transport of fluorescent model compounds
induced by palmitoylcarnitine chloride across the human intestinal epithelial
cell line Caco-2.
AB - Long-chain acylcarnitines, such as palmitoylcarnitine chloride (PCC), are
endogenous compounds which have been shown to increase intestinal transport of
small hydrophilic compounds (including some pharmaceutical agents) through the
paracellular pathway. However, the size range of the compounds whose absorption
can be improved by PCC has not been fully investigated. In the present study, we
systematically examined the effect of PCC on the transport rate of a series of
hydrophilic fluorescent model compounds of varying molecular weights (0.3-71.2
kD) across cultured monolayers of the human intestinal epithelial cells Caco-2.
Mucosal addition of 100 or 200 microM PCC resulted in comparable time-dependent
decreases in the transepithelial electric resistance (T1/2, approximately 15
min). PCC addition induced a striking increase in the transport of sodium
fluorescein (Flu-Na; 0.3 kD) and a slight or moderate increase in transports of
fluorescent compounds of 0.6-11 kD. The effect of PCC on transport of compounds
with molecular weights of > or = 17 kD appeared to be negligible. Examination by
confocal laser scanning microscopy clearly revealed dilated paracellular spaces
in Caco-2 monolayers which had been mucosally pretreated with PCC, confirming
that PCC increases intestinal permeability by opening a paracellular transport
pathway. Our results suggest that PCC is particularly effective in enhancing
intestinal absorption of small hydrophilic compound like Flu-Na and may also have
limited use in promoting the transport of compounds of < or = 10 kD.
PMID- 9769020
TI - Disulfide cross-linked Fab-aggregates: preparation and biodistribution.
AB - The high-molecular-weight soluble aggregates of Fab fragments of murine
antibodies against cardiac myosin were prepared as a potential long-circulating
and low immunogenic pharmaceutical carriers by conjugation of thiolated Fab and
Fab modified with succinimidyl 3-(2-pyridyldithio)propionate. The clearance time
and biodistribution of 111In-radiolabeled aggregates were studied in normal and
nude-mice bearing human breast tumor implant and in rabbits with experimental
myocardial infarction. The aggregates had a prolonged circulation time (half
clearance time ca. 3-5 h) and ability to concentrate in the tumor and in the
necrotic area of infarcted myocardium. Similar tumor-to-normal and infarct-to
normal accumulation ratios (ca. 3 h in both cases) suggest that combination of
long circulation with impaired filtration in necrotic tissues is responsible for
this accumulation rather than a specific interaction. The aggregates prepared may
serve as long-circulating drug carriers able to deliver pharmaceuticals into
areas with affected and leaky vasculature.
PMID- 9769021
TI - Production and characterization of fusion proteins containing transferrin and
nerve growth factor.
AB - To explore the ability to use genetic fusions of transferrin as a carrier for
brain targeting and delivery, a series of fusion proteins containing both human
nerve growth factor (NGF) and human transferrin was produced in mammalian cells.
A protein in which the hinge region from human IgG3 joined the carboxyl terminus
of NGF and the amino terminus of transferrin formed a covalent homodimer, bound
human transferrin receptor, and retained full NGF in PC12 cells. In contrast,
proteins in which polypeptide dimerization was not induced or in which NGF was
fused through its amino terminus had greatly reduced NGF activity. The ability to
maintain both biologically active NGF and transferrin as part of a fusion protein
may offer a novel way to deliver NGF and other neurotrophic factors to the
central nervous system.
PMID- 9769022
TI - QSAR analysis of polyamine transport inhibitors in L1210 cells.
AB - PURPOSE: In this paper, the authors attempt to construct a mathematical model to
correlate the biological activities of 63 polyamine transport inhibitors in L1210
cells with their physicochemical parameters. METHOD: The inhibitory constants
(Ki) were obtained from the published work of Bergeron et al. Non-weighted least
square method was used in deriving the regression equations with a BMDP program.
An AM1 subroutine of the HyperChem program was used to optimize the geometry and
calculate the molecular dipole moments and the distance between two terminal
amino groups. A CQSAR program was used to calculate Clog P (oct./w.). RESULTS: A
good correlation (r2 = 0.81) was obtained by using a five-parameter equation
including the distance between two terminal amino groups (d), the number of
cationic charge (Charge), molecular weight (MW), dipole moment (mu), and hydrogen
bond forming ability (Hb). CONCLUSION: This model accounts for 81% of the
variance in the data and can be used to estimate transport-inhibitory activity of
many other polyamine analogues. It gives some quantitative information about the
relationship between the polyamine analogues' function as transport inhibitors
and their molecular structures.
PMID- 9769023
TI - Glial cell reactions in neurodegenerative diseases: pathophysiology and
therapeutic interventions.
AB - A variety of proteins known to be involved in inflammatory processes are
associated with lesions in chronic neurodegenerative disorders such as Alzheimer
disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS).
This is particularly true of AD, in which inflammatory reactions are believed to
be important contributors to the neuronal loss. Inflammatory proteins associated
with AD include complement proteins, complement inhibitors, acute-phase
reactants, inflammatory cytokines, proteases, and protease inhibitors. Studies of
cultured human astrocytes and microglia obtained from postmortem brain have
established that almost all of these proteins are produced by one or the other of
these two cell types. Human neurons also produce many inflammatory proteins and
their inhibitors, creating complex interactions. Accumulations of amyloid,
extracellular tangles, or Lewy bodies apparently act as irritants, causing the
activation of complement, the initiation of reactive changes in microglia, and
the release of potentially neurotoxic products such as the membrane attack
complex, oxygen free radicals, and excess glutamate. A number of epidemiologic
studies indicate that populations taking anti-inflammatory drugs have a sharply
reduced prevalence of AD. One small clinical trial with indomethacin showed
arrest of the disease over a 6-month period. Therapeutic intervention in key
inflammatory processes holds great promise for the amelioration of AD and
possibly other neurodegenerative disorders.
PMID- 9769024
TI - A strategy for identifying immunosuppressive therapies for Alzheimer disease.
AB - There is increasing evidence that the immune system plays an important role in
the pathology of Alzheimer disease (AD). The fundamental steps in this process
involve induction of neurotoxic microglia by senile plaques. Recent studies have
shown that microglia in contact with isolated plaque fragments secrete
neurotoxins that can cause neuronal injury and brain damage typical of AD. In
vitro models help to delineate individual steps of this activation cascade by
which quiescent microglia become neuron-killing cells. Moreover, such model
systems provide rapid screening assays to identify immunosuppressive drugs that
might slow brain damage brought on by neurotoxic microglia.
PMID- 9769025
TI - Properties of activated microglia and pharmacologic interference by
propentofylline.
AB - Ameboid microglia are activated macrophages in the developing brain. With age,
these cells undergo gradual transformation into the adult form, known as ramified
or resting microglia. In response to neuronal insults, microglia change their
morphology and immunophenotype and proliferate to become full-blown brain
macrophages. Microglia release a battery of neurotoxic substances. Responses to
neuronal damage occur at various intervals after the insult, suggesting that
microglia may be an attractive target for pharmacologic intervention. The
cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients contains antibodies
that recognize activated microglia in the developing rat and in the ischemic
gerbil brain. These results suggest that AD shares common mechanisms related to
the activation of microglia with both these experimental models. In vitro, the
xanthine derivative propentofylline (PPF) depresses the production of reactive
oxygen intermediates produced by macrophages. To appreciate in vivo interactions
of PPF, two models were employed: developing rats and adult gerbils exposed to
ischemia. Newborn rats were administered PPF (10 mg/kg) for 7 days. Gerbils were
exposed to 5 min of transient forebrain ischemia and received PPF (10 mg/kg) 24 h
later until the day before sacrifice. Animals were sacrificed at 7 or 14 days
after reperfusion. Brains were processed for immunocytochemistry. Reactive
microglia were visualized with monoclonal antibodies OX18 and OX42 or AD-CSF
microglia antibodies. In the case of ischemia, an antibody against the amyloid
precursor protein (APP) (residues 676-695) was included. Newborn rats receiving
PPF for 7 days displayed a dramatic reduction in the number of activated
microglia compared with untreated littermates. Ischemic control in gerbils showed
complete nerve death, accumulations of APP, and enhanced microglial reactivity.
In gerbils receiving PPF, APP accumulation was absent or very slight, and
activated microglia were downregulated. The ability of PPF to interfere with
activated microglia suggests that this agent may be useful for slowing
progressive nerve cell death associated with AD, which is considered to be
largely influenced by pathologic glial reactions.
PMID- 9769026
TI - Interfering with the pathologic activation of microglial cells and astrocytes in
dementia.
AB - Cascading glial cell activation is believed to play an essential pathogenic role
in the development of dementia. Reactive microglia may contribute to neuronal
damage by the generation of free oxygen radicals and nitric oxide (NO), which
forms the particularly aggressive peroxynitrites, and by the release of
potentially neurotoxic cytokines such as tumor necrosis factor-alpha (TNF-alpha).
The pathologically stimulated release of interleukin-1beta (IL-1beta) from
microglial cells triggers secondary activation of astrocytes, which are forced to
proliferate and to give up their differentiated state. As a consequence,
physiologically required astrocyte functions may be impaired, such as uptake of
glutamate and K+ from the extracellular space and release of neurotrophic
factors. At the same time, production of inflammatory proteins which, for
example, promote the formation of toxic beta-amyloids, is reported to be
stimulated in reactive astrocytes. Because the complex molecular signaling that
controls glial cell activation is only beginning to be elaborated, we attempted
to elucidate the role that has been adopted during evolution by the endogenous
cell modulator adenosine. This nucleoside exerts a homeostatic effect on reactive
glial cell functions by a sophisticated control of the second messenger
interplay, counteracting a pathologically induced dysbalance of the Ca2+- and
cAMP-dependent signaling. A strengthening of the cAMP-dependent signaling chains
was found to counteract the proliferation rate, the formation of free oxygen
radicals, and the stimulated release of TNF-alpha and IL-1beta in cultivated
microglia. It also helped proliferative astrocytes to regain their differentiated
state and a mature ion channel pattern. The cAMP-linked homeostatic adenosine
effects could be reinforced or mimicked by propentofylline, a pharmacon that
raises the effective extracellular concentration of adenosine by inhibiting its
cellular reuptake and increases the cellular cyclic nucleotide content by
selective phosphodiesterase inhibition. We conclude that a pharmacologically
reinforced homeostatic control of the pathologically altered Ca2+/cAMP crosstalk
may prevent glia-related neuronal damage, providing a potential option for the
treatment of dementia.
PMID- 9769027
TI - Propentofylline in the treatment of vascular dementia and Alzheimer-type
dementia: overview of phase I and phase II clinical trials.
AB - Pathophysiologic processes common to both vascular (multi-infarct) dementia and
dementia of the Alzheimer type may include microglial activation with resultant
generation of inflammatory cytokines and neurotoxic free radicals, decreased
secretion of nerve growth factor by astrocytes, excess release of glutamate with
associated neurotoxicity, and loss of cholinergic neurons. The functional
benefits and neuroprotective effects of propentofylline (PPF) stem from its
interference with these overlapping pathways of neurodegeneration. The clinical
pharmacology and safety of PPF were studied in a number of phase I studies in
healthy young and elderly adults and in patients with renal or hepatic
impairment. These studies have shown that PPF 300 mg t.i.d. is safe and well
tolerated when taken on an empty stomach 1 h before meals. In a randomized,
double-blind phase II study involving 190 elderly subjects with clinically and
psychometrically documented mild to moderate dementia, 12 weeks of PPF therapy
produced significantly greater improvements than placebo in Gottfries-Brane-Steen
(GBS) scores, Mini-Mental State Examination (MMSE) scores, and Clinical Global
Impression (CGI) ratings. A subsequent phase II study using positron emission
tomography (PET) revealed that cortical glucose metabolism improved significantly
in patients with vascular dementia after 12 weeks of PPF treatment but
deteriorated significantly with placebo. A third phase II study, which enrolled
patients with Alzheimer-type dementia, demonstrated that PPF significantly
enhanced functional reserve, as reflected by increases in regional cerebral
glucose metabolism after stimulation with a verbal memory task. In contrast,
patients randomized to placebo exhibited a significant decline in functional
activation and significant worsening in their MMSE scores over the course of this
12-week study. Propentofylline proved to be safe, well tolerated, and free of
severe side effects in all three of these phase II trials. Phase I trial results
suggest that significant food interactions occur with PPF, indicating that the
drug should be taken on an empty stomach 1 h before meals. Phase II trial results
indicate that PPF yields clinically measurable improvements in the symptoms of
dementia and prevents loss of stimulation-related increases in glucose metabolism
over a treatment period of 3 months. Whether these results indicate that PPF can
slow the progression of dementia can be determined only by long-term trials
specifically designed to determine the drug's effect on disease progression.
PMID- 9769028
TI - The trophic effects of purines and purinergic signaling in pathologic reactions
of astrocytes.
AB - This article reviews the effects of extracellular purine bases, nucleosides, and
nucleotides as intracellular signaling molecules with trophic effects on cells
after insults to the brain and spinal cord. Astrocytes are the principal source
of extracellular purines in brain after injury, ischemia, or trauma. In vitro and
in vivo extracellular purines have both immediate and long-term trophic effects,
including stimulation of astrocyte and neuronal differentiation, mitosis,
morphogenesis, apoptosis, and stimulation of growth and trophic factor synthesis.
The effects of the nucleoside adenosine and the nucleotide adenosine triphosphate
(ATP) are mediated principally via specific receptors on the cell surface coupled
to a series of signaling cascades. Unlike adenosine and ATP, guanosine and
guanosine triphosphate (GTP) do not act at classical purine receptors. However,
they exert similar effects on astrocytes, apparently by causing the astrocytes to
release large amounts of adenosine and ATP over prolonged periods. The release of
adenosine and ATP may be related to the effects of guanosine on the purine
nucleoside transporters in the cell membrane, whereas the release of ATP may be
due to the effects of GTP on the ATP-binding cassette (ABC) proteins.
Physiologically, the effects of guanosine are important because this nucleoside,
unlike adenosine, remains elevated for prolonged periods after brain injury.
PMID- 9769029
TI - Current concepts in joint replacement.
PMID- 9769030
TI - Millennium arthroplasty: materials, methods, & mechanisms.
PMID- 9769031
TI - Factors influencing polyethylene wear in total joint arthroplasty.
PMID- 9769032
TI - The clinical picture of debris generation: map reading.
PMID- 9769033
TI - Osteolysis: dealing with the consequences.
PMID- 9769034
TI - Porous-coated total hip arthroplasty in the young.
PMID- 9769035
TI - Hydroxyapatite: catalyst or conjurer?
PMID- 9769036
TI - Femoral fixation algorithm for what works.
PMID- 9769037
TI - The cemented all-polyethylene acetabular total hip arthroplasty.
PMID- 9769038
TI - The acetabular component: an elliptical monoblock alternative.
PMID- 9769039
TI - Hip arthroscopy for acetabular dysplasia: a pipe dream?
PMID- 9769040
TI - Nerve injury in the prosthetic management of the dysplastic hip.
PMID- 9769041
TI - Periprosthetic fractures associated with total hip arthroplasty.
PMID- 9769042
TI - Blood conservation in total joint arthroplasty.
PMID- 9769043
TI - Reconstruction at a high hip center in acetabular revision surgery using a
cementless acetabular component.
PMID- 9769044
TI - Distal fixation with fully coated stems in femoral revision: a 16-year follow-up.
PMID- 9769045
TI - Proximal femoral allografts for reconstruction of bone stock in revision hip
arthroplasty.
PMID- 9769046
TI - Acetabular revision options.
PMID- 9769047
TI - Back to the future: evolution in hip design.
PMID- 9769048
TI - A femoral component for hip replacement.
PMID- 9769049
TI - Calcium sulfate bone-void filler.
PMID- 9769050
TI - Adventures in mobile-bearing knee design: a mid-life crisis.
PMID- 9769051
TI - DVT prophylaxis options: facts & fictions.
PMID- 9769052
TI - Mobile-bearing joint replacement options in post-traumatic arthritis of the knee.
PMID- 9769053
TI - Putting it all together: the importance of the trial reduction in total knee
replacements.
PMID- 9769054
TI - Alternative surveillance after total knee arthroplasty: a viable option?
PMID- 9769055
TI - Repairing minor bone defects: augmentation & autograft.
AB - Numerous options exist for management of minor bone defects associated with TKA.
Biomechanical data demonstrate that filling defects with methylmethacrylate, with
or without screw augmentation, results in inferior load transfer. Rectangular
augmentations may be superior to angular wedges due to reduction in shear
stresses. Controversy persists regarding superiority of use of bone graft versus
augmentation. The author favors bone graft for cavitary defects, massive bone
loss, and in younger patients in whom additional revision surgery is likely.
Prosthetic augmentation is favored in peripheral defects of moderate size in more
elderly patients.
PMID- 9769056
TI - Morselized allografting in revision total knee arthroplasty.
PMID- 9769057
TI - Structural bone grafting about the knee.
PMID- 9769058
TI - Management of extensor mechanism complications.
PMID- 9769059
TI - Periprosthetic fractures following total knee arthroplasty: the good, bad, &
ugly.
PMID- 9769060
TI - Common litigation problems: dueling with the devil.
PMID- 9769061
TI - Cost reduction in total joint arthroplasty.
PMID- 9769062
TI - Hip challenges: what would you do?
PMID- 9769063
TI - Knee challenges: what would you do?
PMID- 9769064
TI - Normal plasma lactose concentrations and kinetics of intravenously infused
lactose in cattle.
AB - Plasma lactose concentration and its kinetics were determined in apparently
normal cattle, as a prelude to investigating its chemotherapeutic significance in
bovine trypanosomiasis. It is hoped that intravenously administered lactose may
be able to reduce the rate of sequestration of desialylated erythrocytes during
Trypanosoma vivax infection of cattle; thus decreasing the rate of development of
trypanosomal anaemia in infected animals. A range of 0.061 to 0.55 mM with a mean
of 0.208 +/- 0.128 mM standard deviation (SD), observed in adult cattle was
significantly lower (P<0.001) than corresponding values in recently weaned
calves; 0.429 to 1.496 mM (0.972 +/- 0.318 mM). Semi-logarithmic plots from
calves given a single dose (0.5 g lactose per kg bodyweight as a solution in
normal saline, infused at the rate of 18 ml min(-1)) showed a biexponential
pattern of regression lines. Decrease in plasma concentrations was biphasic and
lactose was rapidly distributed into the extravascular space after
administration. The biological half-life (t1/2) of the infused lactose ranged
from 4.10 to 6.00 hours (5.01 +/- 0.81 hours); its mean elimination rate constant
was 0.14 +/- 0.02 hour(-1), mean apparent volume of distribution was 168.09 +/-
56.65 ml kg(-1) while its mean total clearance was 23.54 +/- 8.31 ml kg(-1) hour(
1). A single dose rapidly reached a peak and gradually fell below the pre
infusion level while repeated doses did not cause accumulation of the lactose in
the plasma as each infusion fell back to normal relatively rapidly.
PMID- 9769065
TI - Ricobendazole kinetics and availability following subcutaneous administration of
a novel injectable formulation to calves.
AB - The plasma and abomasal fluid disposition kinetics of ricobendazole (RBZ) after
subcutaneous (s.c.) administration of a novel injectable formulation to calves,
and the comparative plasma availability after s.c. injection of RBZ and that
obtained after oral treatment with albendazole (ABZ), were characterised. Six
parasite-free Holstein calves received RBZ (solution 150 mg ml(-1)) by s.c.
injection at 3.75 mg kg(-1) (Experiment 1). Experiment 2 was conducted in two
experimental phases; in phase I, five calves (Group A) received RBZ by s.c.
injection and five animals (Group B) were orally treated with ABZ (suspension 100
mg ml(-1)), at 5 mg kg(-1). Drug treatments were reversed for each group in phase
II and given at 7.5 mg kg(-1). Samples of abomasal fluid (via cannula) and
jugular blood were collected over 72 hours post-treatment and analysed by HPLC.
RBZ and its sulphone metabolite were detected in plasma following its s.c.
administration. RBZ was rapidly absorbed, reaching the plasma Cmax at 4.5 hours
post-dosing. The sulphone metabolite followed a similar kinetic pattern. Both
molecules were rapidly and extensively distributed into the abomasum, being
detected in abomasal fluid between 30 minutes and 36 hours post-administration.
An extensive plasma/abomasum exchange process, with ionic-trapping in the
abomasum, accounted for the higher AUC value (>200 per cent) obtained for RBZ in
abomasum compared with plasma. The s.c. treatment with RBZ formulated as a
solution resulted in a significantly greater plasma availability (measured as ABZ
sulphoxide) than the oral treatment with ABZ (suspension) given at the same dose
rates.
PMID- 9769066
TI - Detection of avian reovirus RNA and comparison of a portion of genome segment S3
by polymerase chain reaction and restriction enzyme fragment length polymorphism.
AB - A reverse transcription-polymerase chain reaction (RT-PCR) was established to
amplify a 672-base pairs fragment on the segment S3 of avian reovirus (ARV). The
amplified fragments were detected in nine strains of ARV as well as three tendon
tissue specimens, indicating that the primer regions were well conserved. The RT
PCR was able to detect as low as 0.2 pg using an ethidium bromide stained gel.
The detection limit could be enhanced further to 0.04 pg by hybridisation after
southern transfer. The amplified DNA fragments from nine ARV strains and two
tissue specimens showed different restriction enzyme cleavage patterns. Analysis
of the data revealed that these 11 strains were classified into four groups. The
results suggest that PCR followed by restriction enzyme analysis may provide a
simple and rapid method for the characterisation of ARV isolates.
PMID- 9769067
TI - CT-assisted versus silicone rubber cast morphometry of the lower respiratory
tract in healthy amazons (genus Amazona) and grey parrots (genus Psittacus).
AB - The objective of this study was to examine the normal respiratory tract of grey
parrots and amazons by using two different methods. The lower respiratory tract
of five amazons and four grey parrots, all healthy, were investigated applying
computerised tomography (CT). Volumes and densities of the body, the body
cavities, the normal lungs, and the airsacs in the living animals were defined as
reference values of healthy birds to give a basis for future CT-diagnosis of
respiratory diseases and their precise locations in parrots. In a parallel study,
the lung and air sac volumes of six amazons and two grey parrots were measured
using silicone rubber casts produced after the method described by H.-R. Duncker.
Values for identical respiratory structures gained by these different methods
were compared.
PMID- 9769069
TI - Comparative development of antitrochanteric disease in male and female turkeys of
a traditional line and a contemporary sire-line fed ad libitum or with restricted
quantities of food.
AB - The prevalence of musculoskeletal disease at eight, 16, 24, 34, 44 and 54 weeks
of age in male and female turkeys was determined by dissecting 688 limbs from
traditional lines and sire-line turkeys fed to achieve different bodyweights.
Traditional turkeys were fed ad libitum and sire-line turkeys were fed ad libitum
or restricted to 0.5 during rearing and subsequently to 0.8 of ad libitum-fed
bodyweight of birds of the same strain and sex. A group of male sire-line turkeys
was also fed ad libitum to 18 weeks and 0.8 of ad libitum thereafter. Lameness
during the rearing period was usually associated with joint infection. Ruptured
ligaments were an occasional finding in sire-line turkeys before sexual maturity.
The major finding at 34, 44 and 54 weeks of age was degeneration of the
antitrochanter in both sexes of the sire-line. The prevalence and severity of
disease increased with age but was not generally associated with lameness.
Antitrochanteric degeneration in the sire-line was diminished by decreasing
bodyweight through food restriction. Antitrochanteric degeneration did not occur
in traditional turkeys.
PMID- 9769068
TI - Intestinal permeability of Irish setter puppies challenged with a controlled oral
dose of gluten.
AB - A combined test of intestinal permeability using lactulose (L) and rhamnose (R),
and absorptive function using xylose (X) and 3-O-methylglucose (G), was carried
out at four, six, eight and 16 weeks of age in 22 healthy control and six gluten
sensitive Irish setter (IS) dogs fed a diet containing a controlled dose of
gluten from weaning. Comparisons were made with two groups of 12 healthy control
dogs of breeds other than IS, one fed the same diet as the setters and the other
fed a gluten-free diet. Gluten-sensitive IS showed a rise in permeability (mean
[SEM] urinary L/R) from 0.23 (0.07) at four weeks to 0.39 (0.05) at eight weeks,
remaining at 0.36 (0.04) at 16 weeks. These results were significantly higher in
gluten-sensitive than control IS at six, eight and 16 weeks, compatible with
jejunal biopsy lesions characteristic of gluten-sensitive enteropathy
demonstrated in affected dogs at 16 weeks. Urinary L/R ratios of control dogs of
breeds other than IS peaked at six weeks 0.27 (0.02), and were significantly
higher than those of control IS at six and eight weeks, demonstrating differences
in permeability between Irish setter dogs and other breeds at this age. There
were no significant differences in urinary X/G ratios at six, eight and 16 weeks
of age between any of the groups of dogs challenged with gluten. Urinary L/R and
X/G ratios were similar in the control dogs of breeds other than IS fed gluten
containing and gluten-free diets. These findings indicate that intestinal
permeability testing of puppies during controlled oral gluten challenge provides
a practical screening test for gluten sensitivity in Irish setter dogs at an
early age.
PMID- 9769070
TI - Investigation of the cellular tropism of bovine immunodeficiency-like virus.
AB - Bovine immunodeficiency-like virus (BIV) was first isolated from an animal
showing transient leucocytosis, lymphadenopathy, lesions in the central nervous
system and progressive weakness and emaciation. Similar signs are observed in
other immunosuppressive lentiviral infections. BIV, like other lentiviruses, has
been isolated from peripheral blood mononuclear cells and lymphoid tissue of
infected animals. However, the in vivo cellular tropism of BIV remains unclear
although initial studies indicate that BIV may be pantropic, infecting T cells, B
cells and monocytes similar to some of the immunodeficiency-causing lentiviruses.
PCR, Southern blot hybridisation, cell culture and reverse transcriptase assays
were used to demonstrate the presence of BIV proviral DNA and the production of
infectious virus in CD2+, WC1+, B cells and monocytes during the acute stages of
infection. Western immunoblot assays were used to assess the development of
antibody responses towards the virus.
PMID- 9769071
TI - Effects of hypercapnia on endocrine and metabolic responses to anaesthesia in
ponies.
AB - Some metabolic and endocrine effects of hypercapnia were studied in six ponies
during halothane anaesthesia with neuromuscular blockade and controlled
ventilation. Each was anaesthetised twice, once with a 40-minute-period of
hypercapnia (10 kPa) and once when normocapnia (5.3 kPa) was maintained
throughout two hour's anaesthesia. Routine cardiovascular monitoring was
performed and blood samples were taken for assay of cortisol, insulin, glucose,
lactate, muscle and liver enzymes and total protein. Anaesthesia induced
hypotension and lacticacidaemia which were slightly ameliorated during
hypercapnia. Hyperglycaemia was more marked during hypercapnia. Plasma cortisol
increased in a similar manner in both groups and insulin tended to decrease.
There were no major changes in the other variables measured. It was concluded
that 40 minutes of hypercapnia during halothane anaesthesia in ponies may have
improved perfusion and did not markedly alter the stress response.
PMID- 9769072
TI - Breath hydrogen measurement in ponies: a preliminary study.
AB - The aim of this study was to establish the normal patterns of breath hydrogen
excretion in adult ponies following either voluntary consumption or
administration per stomach tube of a test meal/carbohydrate substrate. After an
overnight fast, the ponies (n = 7) received either no test meal (ie fasted),
glucose, xylose, lactose, lactulose, wheat flour or oats. Exhaled breath samples
were collected in duplicate at 0 minutes and at 30-minute intervals thereafter
for eight hours. Analysis of duplicate breath hydrogen measurements (n = 714)
indicated that the breath hydrogen collection/storage method was reliable.
Fasting resulted in negligible levels of breath hydrogen excretion. Increases in
breath hydrogen concentration greater than 10 ppm, sustained for at least 30
minutes, were regarded as being biologically significantly different than fasting
data and were observed for all ponies following the ingestion of oats or the
administration of wheat flour, for three ponies following the administration of
glucose and xylose and for two ponies following the administration of lactulose
and lactose. The pattern of breath hydrogen excretion was subject to variation
between animals following the ingestion of identical test meals. This study
provides evidence of incomplete glucose absorption in healthy ponies and
indicates that ingestion of non-absorbable carbohydrates do not always result in
hydrogen excretion.
PMID- 9769073
TI - The accuracy and reliability of linear measurements of the ulna for
anthropometrical studies in dogs.
AB - This study investigated the accuracy and reliability of measuring the distance
between two surface landmarks (the point of the tuber olecrani and the proximal
aspect of the stopper pad) as an indication of ulna length in the live dog. It
was found that the chosen skin landmarks did correlate well with the length of
the ulna bone. The reliability of such measurements was high when performed by a
single person, however this fell to unacceptable levels when multiple people were
used to make the measurements. It was concluded that if this technique was to be
used in studies to serially record the bone length in live growing dogs, then the
measurements should be taken by a single person.
PMID- 9769074
TI - Evaluation of B and T lymphocytes and plasma cells in colonic mucosa from healthy
dogs and from dogs with inflammatory bowel disease.
AB - The aim of this study was to investigate the subpopulations of lymphocytes in the
colonic mucosa of healthy dogs and dogs with inflammatory bowel disease (IBD).
Fourteen normal dogs and 13 dogs with IBD were examined. Endoscopic biopsy
specimens of colonic mucosa from each dog were stained specifically for pan T
lymphocytes (CD3) and pan B lymphocytes (CD79a), and for plasma cells with methyl
green pyronin (MGP) stain. Cells were counted by means of a grid and statistical
analysis was performed on the data collected. B and T lymphocytes were also
counted in the glandular epithelium of normal dogs and dogs with IBD and the
normal and abnormal groups compared statistically. Healthy dogs had significantly
lower numbers of T cells in the lamina propria and glandular epithelium and
significantly lower numbers of B cells in the lamina propria. Significant group
differences for plasma cells were not evident. Our results indicate that in IBD a
chronic cellular immune reaction is present in the diseased gut involving
increased numbers of B and T lymphocytes.
PMID- 9769075
TI - Effects of Trypanosoma congolense and nutritional supplements in Djallonke ewes
on live weight during pregnancy, post partum weight, haematology parameters and
lamb performance.
AB - The effects of Trypanosoma congolense infection and nutritional supplements on
live weight changes during pregnancy, haematology traits and offspring
performance were studied in 42 Djallonke ewes. A randomised block design was used
to allocate ewes to four treatment combinations, of which two were on a
restricted diet (L) and the remainder on an unrestricted diet (H). Half of each
nutritional group were infected with T congolense (LI, HI), the remainder serving
as controls (LC, HC). The degree of anaemia following infection was similar in
both infection groups (P<0.0001), but the erythropoietic activity, as judged by
the increase in mean corpuscular volume, was significantly greater in the HI
group (P<0.01). Live weight gains during pregnancy attributable to higher
supplements were significantly depressed by infection (P<0.01). Post partum
weight was lower in the LI group as compared with the LC control. Diet interacted
significantly (P<0.01) with infection and resulted in the lowest lamb growth
rates in the LI group. It was concluded that dietary supplementation of
trypanosome-infected Djallonke ewes during pregnancy and lactation improves
productivity in terms of ewe live weight and improved lamb growth rates to
weaning.
PMID- 9769076
TI - Impairment of gas exchange due to alveolar oedema during xylazine sedation in
sheep; absence of a free radical mediated inflammatory mechanism.
AB - We studied the mechanism of impairment of gas exchange following sedation with
the alpha2 adrenoreceptor agonist, xylazine, in Suffolk cross-bred sheep
spontaneously breathing room air. Xylazine caused a significant fall in PaO2 from
a mean (pre-xylazine) of 97.9 mm Hg (6.7 mm Hg SEM) to a mean of 38.1 mm Hg (3.2
mm Hg SEM) one minute after injection with a transient increase in PaCO2 from a
mean (pre-xylazine) of 32.6 mm Hg (1.9 mm Hg SEM) to a mean of 40.2 mm Hg (3.0 mm
Hg SEM). There was no significant fall in mean arterial pressure or in white cell
count. There was no significant change in a number of indices of free radical
release which included ascorbyl radical, plasma antioxidant potential and alpha
tert-butyl phenyl nitrone (PBN) spin adduct measured simultaneously in both
arterial and venous blood. In all sheep given xylazine there was no histological
evidence of platelet emboli but lung histopathology showed evidence of pulmonary
oedema and intense microvascular congestion with red cells extravasated into
alveoli. No such histological changes were seen in the lungs of normal sheep. The
impaired gas exchange during sedation with xylazine in sheep is caused, not by an
oxidant mediated inflammatory mechanism or by platelet emboli, but by intense
alveolar oedema which is probably due to pulmonary venospasm.
PMID- 9769077
TI - Pharmacokinetics of amoxicillin/clavulanic acid combination after intravenous and
intramuscular administration to pigeons.
AB - The pharmacokinetics of amoxicillin/clavulanic acid (4:1) combination were
studied after intravenous and intramuscular administration of single doses (25 mg
kg(-1) bodyweight) to 50 pigeons. The plasma concentrations-time data were
analysed by compartmental pharmacokinetics and non-compartmental methods. The
disposition curves for both drugs after intravenous administration were best
described by a two-compartment open model. The apparent volumes of distribution
of amoxicillin and clavulanic acid were 1.77 litres kg(-1) and 1.30 litres kg(-1)
respectively. The body clearances of amoxicillin and clavulanic acid were not
significantly different. The elimination half-lives of amoxicillin after
intravenous and intramuscular administration were 1.22 (0.09) hour and 1.52
(0.09) hour respectively, and those of clavulanic acid were 1.15 (0.08) hour and
1.49 (0.08) hour. After intramuscular administration both drugs had a
significantly longer half-life (P<0.05) than that after the intravenous
treatment. The bioavailability after the intramuscular injection was high and
similar for both drugs (75.98 per cent for amoxicillin and 74.61 per cent for
clavulanic acid). The mean peak plasma concentration of clavulanic acid (0.29
hour) was reached earlier than amoxicillin (0.38 hour) and peak concentrations
were proportional to the dose of both products administered (5.81 mg litre(-1) of
amoxicillin and 1.89 mg litre(-1) of clavulanic acid). From a single
administration it is proposed that an intramuscular dosage regimen of 105 mg kg(
1) of the combination (84 mg kg(-1) of amoxicillin and 21 mg kg(-1) of clavulanic
acid) every 12 hours will achieve minimum concentrations > or =0.5 mg litre(-1)
(minimum inhibitory concentration of most susceptible pathogens).
PMID- 9769078
TI - Biochemical analysis of serum and cerebrospinal fluid in clinically normal adult
camels (Camelus dromedarius).
AB - The concentrations of total protein, glucose, cholesterol, triglyceride, urea
nitrogen, creatinine, sodium, potassium, chloride, calcium, inorganic phosphorus,
copper, magnesium, and iron and the activities of aspartate aminotransferase
(AST), alanine aminotransferase, (ALT), alkaline phosphatase (ALP), lactate
dehydrogenase (LD), creatine kinase (CK) and amylase were determined in
cerebrospinal fluid (CSF) and serum from 21 clinically healthy adult camels. The
concentrations of sodium, potassium and chloride in CSF were similar to those of
serum; whereas the values for all other constituents were significantly higher
(P<0.05) in serum than in CSF.
PMID- 9769079
TI - Species identification of Streptococcus porcinus by restriction fragment length
polymorphism analysis of 16S ribosomal DNA.
AB - Streptococcus porcinus reference strains and routine isolates belonging to
Lancefield's serogroup E, P, U and V and to various serotypes of serogroup E were
examined for their 16S ribosomal DNA fingerprint pattern. Oligonucleotide primers
complementary to 16S rRNA genes were used to amplify gene fragments by polymerase
chain reaction from genomic DNA. The amplified 1450 bp fragment was subsequently
digested with the restriction enzyme BpiI resulting in two fragments with a size
of approximately 1250 bp and 200 bp. All 45 S porcinus investigated in the
present study could be identified on the basis of this characteristic 16S rDNA
fingerprint pattern and clearly differentiated from 16 control strains of various
species and serogroups of genus Streptococcus. The present results demonstrate
the potential application of 16S rDNA analysis for identification of S porcinus,
a species which might express various group- and type-specific antigens.
PMID- 9769080
TI - Neopterin values in selected groups of normal animals.
AB - To establish baseline information on neopterin concentrations in livestock,
companion and laboratory animals and identify the factors that may influence
these concentrations, blood samples were taken from normal dairy cattle, horses,
llamas, dogs, cats and rats of varying ages and sexes. In addition, neopterin
concentrations in normal, adult equines were compared with those found in racing
Thoroughbreds. There were no differences due to sex, sexual maturity, pregnancy,
castration, or age. For all ages and sexes combined, mean neopterin
concentrations were significantly lower in llamas (2.27+/-0.33 nmol litre(-1))
and rats (2.13+/-0.21 nmol litre(-1)) when compared with the other species
tested. Racing Thoroughbreds demonstrated higher neopterin values than adult
equines not in training (3.54+/-0.64 vs 3.13+/-1.02 nmol litre(-1)).
PMID- 9769081
TI - Application of genetic methods to study the relationship between classical swine
fever outbreaks.
AB - Eleven viruses isolated between 1993 and 1997 from outbreaks of classical swine
fever in the neighbouring countries of Slovakia, The Czech Republic and Austria
were compared after partial sequencing of the NS5B and E2 genes. Viruses
collected from South-Central and West Slovakia were indistinguishable during a
period of four years, even when associated with outbreaks of variable severity.
Outbreaks that occurred in the Czech Republic in 1996 involved two types of
virus, one of which was related to the Slovakian outbreaks, and the other to
Austrian outbreaks. The results show that the molecular-genetic approach can
reveal epizootiological relationships between outbreaks that would not otherwise
be apparent. Furthermore, the relative genetic stability of the classical swine
fever virus in the field, means that quite small sequence differences can have
epizootiological significance.
PMID- 9769083
TI - Designing for consumers.
PMID- 9769082
TI - Equine peripheral blood mononuclear cells proliferate in response to tetanus
toxoid antigen.
AB - It has been reported that equine peripheral blood mononuclear cells (PBMNs) do
not proliferate in response to tetanus toxoid (TT) (Frayne and Stokes 1995,
Research in Veterinary Science 59, 79-81). Here we demonstrate that lymphocyte
proliferation responses to TT, which are characteristic of a recall antigen, may
be achieved under certain culture conditions. Given that TT vaccination is
routinely applied to many horses, TT is a suitable antigen for the investigation
of cellular immune responses by peripheral blood mononuclear cells in the horse.
PMID- 9769084
TI - Applying the BeSafe method to product safety evaluation.
AB - The BeSafe (Behavioural Safety) Method, has been developed by International
Mining Consultants Ltd for assessing and reducing risk in industrial contexts.
BeSafe is an ergonomic method of risk analysis and reduction, targeted at
prevention of accidents due to human errors and violations, and emphasising
management strategies for action. In a consumer product environment, accidents
are often due to similar human errors and violations. However, the product usage
environment tends to be diffuse and variable, and its management difficult. Many
controlling measures used to prevent accidents in industry do not apply in this
environment. Using the BeSafe Method, it may be possible to structure safety
assessments of the use of products and target improvement measures. The authors
tested the relevant parts of the method on children's play equipment in
playgrounds, and useful results were obtained. BeSafe could be adapted for other
consumer products in a similar way.
PMID- 9769085
TI - Safety pictograms: are they getting the message across?
AB - This study set out to investigate the role of pictograms in conveying consumer
safety information. The experimental work was carried out in two parts. The first
part investigated UK comprehension levels of 13 product related pictograms. A new
method of judging levels of comprehension of the pictograms was developed. In
general the pictograms surveyed were found to be poorly understood, particularly
those which were abstract in nature. The second part of the research investigated
the effect of different warning styles on noticeability and intended compliance.
This was tested using the new European Standard pictogram developed to convey the
small parts warning on toys. The effect on parents' intended purchase decisions
of different pictograms and or text messages was investigated. Results indicated
that parents' decisions on toy suitability were influenced by the perceived
hazardousness of the product rather than warnings, regardless of their design.
The paper discusses the advantages and limitations of pictograms as a method for
conveying consumer information and makes recommendations for their effective use.
PMID- 9769086
TI - Human factors for pleasure in product use.
AB - Traditionally, human factors have tended to concentrate on making products
'usable'--focusing on utilitarian, functional product benefits. This paper
reports an interview-based study looking at the issue of 'pleasure' in product
use. The study was a 'first pass' at addressing the hedonic and experiential
benefits and penalties associated with product use, and at identifying the
properties of a product that influence how pleasurable or displeasurable it is to
use. Feelings associated with using pleasurable products included security,
confidence, pride, excitement and satisfaction. Displeasurable products,
meanwhile, were associated with feelings that included annoyance, anxiety,
contempt and frustration. The properties of products that were salient in terms
of influencing the level of pleasure/displeasure with a product included
features, usability, aesthetics, performance and reliability. Responses to
questions investigating behavioural correlates to pleasure in product use
suggested that pleasurable products were used more regularly and that future
purchase choices would be affected by the level of pleasure in product use. It is
concluded that the issue of pleasure in product use involves more than usability
alone. As the user's representative in the product creation process, the human
factors specialist should consider many other factors in order to ensure that the
user's experience of product use is maximised.
PMID- 9769087
TI - Mattress evaluation--assessment of contact pressure, comfort and discomfort.
AB - The ergonomic evaluation of mattresses is largely ignored in the current
literature. This is somewhat surprising given their importance and the length of
time spent using them. This study considers some ergonomic aspects of their
design, including body contact pressure and subjective ratings of comfort.
Subjects (12 females) found all of the mattresses tested to be significantly more
comfortable than an incompressible wooden reference surface. However, no
significant differences were found between mattress types, which included
orthopaedic and normal designs. Analysis of body contact pressures (measured at
the shoulder, elbow, hip, knee and ankle) found few significant differences
between experimental conditions. It is argued that limitations in the methodology
may not take account of the change in surface area and anatomical sites of
contact under different conditions of mattress compressibility. No significant
associations were found between comfort ratings and peak body contact pressures.
It seems likely that subjective ratings of mattress comfort are dependent on a
wider set of factors than contact pressure alone, a finding reported elsewhere in
studies of seating.
PMID- 9769088
TI - Is utility in the mind of the beholder? A study of ergonomics methods.
AB - This paper reviews the use of ergonomics methods in the context of usability of
consumer products. A review of the literature indicated that there is upward of
60 methods available to the ergonomist. The results of the survey indicated that
questionnaires, interviews and observation are the most frequently reported
methods used. Ease of use of the methods was dependent upon type of method used,
presence of software support and type of training received. Strong links were
found between questionnaires and interviews as a combined approach, as well as
with HTA and observation. However, a questionnaire survey of professional
ergonomists found that none of the respondents had any documented evidence of the
reliability and validity of the methods they were using. A study of training
people to use ergonomics' methods indicated the different requirements of the
approaches, in terms of training time, application time and subjective
preferences. An important goal for future research is to establish the
reliability and validity of ergonomics methods.
PMID- 9769089
TI - Ergonomics in consumer product evaluation: an evolving process.
AB - As part of its commitment to empowering people to make informed consumer
decisions, the Consumers' Association investigates the convenience aspects of a
vast range of products, from cars to garden spades. Evaluation approaches include
user trials, convenience checklists and expert appraisals. Our methodology is
subject to constant review and refinement to ensure the highest levels of
reliability, validity and auditability. We have a distinctive approach: our tests
are designed to reflect consumer usage and to provide comparative data which is
absolutely fair to all products. This paper discusses the evolving nature of that
methodology within the "lifetime" of a product. Reasons for choosing each method
are given as practical guidance for those involved in comparative testing.
PMID- 9769090
TI - Legibility of video-blended TV menus.
AB - This article describes three experiments relating to the legibility of TV menus.
Special emphasis is placed on the influence of a relatively new feature in TVs:
the possibility to blend graphics and video. Three experiments are presented: one
concentrating on the influences of blending level and video content; one
concentrating on the influences of content and of colour combinations; and one
concentrating on the influences of various font characteristics. The results are
interpreted in terms of guidelines for blended TV menus.
PMID- 9769091
TI - Testing usability with 3D paper prototypes--Case Halton system.
AB - In our study, we set out to see how low-fidelity three-dimensional paper
prototypes could be used to test the usability of two alternative concepts for a
drink can refund machine. The tests were carried out in the real environment with
the actual users of the product. The tests took place before any software or
hardware had been implemented. Using paper prototypes is a quantitative
evaluation method which is easy to apply and suitable for product development
processes with a tight schedule. We found the 3DPP modeling and testing method
turned out to be useful and the results obtained had an influence on the product.
PMID- 9769092
TI - Usage centred research for everyday product design.
AB - Prospective users of a new design in the area of everyday products offer
innumerable opportunities for measurement and observation, in view of both the
diversity in user populations and the freedom of where and how to use a product.
In this paper, the relevance of human data is assessed for their impact in
meeting functional imperatives in a design. On the basis of empirical studies,
the significance of the observation/registration of user activities, including
perceptual and cognitive activities, and the use of actions actually carried out
is demonstrated. For everyday products, these activities are found to be only
loosely related to human characteristics such as sensory capacities, body
dimensions and exertable forces. Such characteristics seem to combine a limited
relevance for usage centred design with relatively easy measurability. In
contrast, observation of user activities may be evasive and is often laborious.
User trialling is seen as an obvious way to enable designers to accommodate
prospective user activities in everyday product design.
PMID- 9769093
TI - A quantitative study of the flexibility contributed to RNA structures by nicks
and single-stranded gaps.
AB - Disulfide crosslinking via thiol-disulfide interchange was applied to quantitate
the relative flexibility contributed by nicks and single-stranded gaps in an RNA
structure. An RNA duplex comprised of three strands was constructed containing
the disulfide crosslink precursors 1 and 2 at opposite ends of the duplex on
opposite strands. The third strand was of varying length to yield a nick or
single-stranded gaps of 1, 2, or 3 nt. Crosslinking rates Indicated relative
flexibilities of the resulting two-helix junctions. Crosslinking in the nicked
duplex occurred two orders of magnitude slower than in a duplex containing a 3-nt
gap. Rates of crosslinking in duplexes with 3-and 2-nt gaps showed only modest
dependence on the gap sequence. Many natural RNAs, including ribozymes, contain
two-helix junctions related to the model system described here. The data suggest
that two-helix junctions containing a nick in one strand will retain substantial
rigidity, whereas one or more single-stranded nucleotides at a two-helix junction
allow significant flexibility.
PMID- 9769094
TI - More than one way to splice an RNA: branching without a bulge and splicing
without branching in group II introns.
AB - Domain 6 (D6) of group II introns contains a bulged adenosine that serves as the
branch-site during self-splicing. In addition to this adenosine, other structural
features in D6 are likely to contribute to the efficiency of branching. To
understand their role in promoting self-splicing, the branch-site and surrounding
nucleotides were mutagenized. Detailed kinetic analysis on the self-splicing
efficiency of the mutants revealed several interesting features. First,
elimination of the branch-site does not preclude efficient splicing, which takes
place instead through a hydrolytic first step. Second, pairing of the branch-site
does not eliminate branching, particularly if the adenosine is involved in a
mispair. Third, the G-U pairs that often surround group II intron branch-points
contribute to the efficiency of branching. These results suggest that there is a
strong driving force for promoting self-splicing by group II introns, which
employ a versatile set of different mechanisms for ensuring that splicing is
successful. In addition, the behavior of these mutants indicates that a bulged
adenosine per se is not the important determinant for branch-site recognition in
group II introns. Rather, the data suggest that the branch-site adenosine is
recognized as a flipped base, a conformation that can be promoted by a variety of
different substructures in RNA and DNA.
PMID- 9769095
TI - Structure and stability of variants of the sarcin-ricin loop of 28S rRNA: NMR
studies of the prokaryotic SRL and a functional mutant.
AB - NMR has been used to examine the conformational properties of two variants of the
sarcin-ricin loop (SRL) from eukaryotic 28S rRNA, which is essential for
elongation factor interactions with the ribosome: (1) its bacterial homologue,
which lacks two of the bases that flank the conserved 12-nt sequence in the
middle of the SRL, but which is functionally equivalent, and (2) a functionally
active variant of the eukaryotic SRL in which the bulged G within the conserved
sequence is replaced by an A. The data indicate that, although the bacterial SRL
is less stable than the eukaryotic SRL, its conformation is closely similar.
Furthermore, even though replacement of the bulged G in the SRL with an A
seriously destabilizes the center of the loop, its effect on the overall
conformation of the SRL appears to be modest. In the course of this work, it was
serendipitously discovered that at neutral pH, the C8 proton of the bulged G, in
both PRO-SRL and E73, exchanges about 10 times faster than it does in GMP.
PMID- 9769096
TI - PRP16, a DEAH-box RNA helicase, is recruited to the spliceosome primarily via its
nonconserved N-terminal domain.
AB - Dynamic rearrangement of RNA structure is crucial for intron recognition and
formation of the catalytic core during pre-mRNA splicing. Three of the splicing
factors that contain sequence motifs characteristic of the DExD/DExH-box family
of RNA-dependent ATPases (Prp16, Prp22, and the human homologue of Brr2) recently
have been shown to unwind RNA duplexes in vitro, providing biochemical evidence
that they may direct structural rearrangements on the spliceosome. Notably,
however, the unwinding activity of these proteins is sequence nonspecific,
raising the question of how their functional specificity is determined. Because
the highly conserved DExD/DExH-box domain in these proteins is typically flanked
by one or more nonconserved domains, we have tested the hypothesis that the
nonconserved regions of Prp16 determine the functional specificity of the
protein. We found that the nonconserved N-terminal domain of Prp16 is (1)
essential for viability, (2) required for the nuclear localization of Prp16, and
(3) capable of binding to the spliceosome specifically at the step of Prp16
function. Moreover, this domain can interact with the rest of the protein to
allow trans-complementation. Based on these results, we propose that the
spliceosomal target of the unwinding activity of Prp16, and possibly other
DExD/DExH-box splicing factors as well, is defined by factors that specifically
interact with the nonconserved domains of the protein.
PMID- 9769097
TI - Programmed frameshifting in the synthesis of mammalian antizyme is +1 in mammals,
predominantly +1 in fission yeast, but -2 in budding yeast.
AB - The coding sequence for mammalian ornithine decarboxylase antizyme is in two
different partially overlapping reading frames with no independent ribosome entry
to the second ORF. Immediately before the stop codon of the first ORF, a
proportion of ribosomes undergo a quadruplet translocation event to shift to the
+1 reading frame of the second and main ORF. The proportion that frameshifts is
dependent on the polyamine level and, because the product antizyme is a negative
regulator of intracellular polyamine levels, the frameshifting acts to complete
an autoregulatory circuit by sensing polyamine levels. An mRNA element just 5' of
the shift site and a 3' pseudoknot are important for efficient frameshifting.
Previous work has shown that a cassette with the mammalian shift site and
associated signals directs efficient shifting in the budding yeast Saccharomyces
cerevisiae at the same codon to the correct frame, but that the shift is -2
instead of +1. The product contains an extra amino acid corresponding to the
shift site. The present work shows efficient frameshifting also occurs in the
fission yeast, Schizosaccharomyces pombe. This frameshifting is 80% +1 and 20%
2. The response of S. pombe translation apparatus to the mammalian antizyme
recoding signals is more similar to that of the mammalian system than to that of
S. cerevisiae. S. pombe provides a good model system for genetic studies on the
mechanism of at least this type of programmed mammalian frameshifting.
PMID- 9769098
TI - Protein-RNA interactions in the U5 snRNP of Saccharomyces cerevisiae.
AB - We present here the first insights into the organization of proteins on the RNA
in the U5 snRNP of Saccharomyces cerevisiae. Photo-crosslinking with uniformly
labeled U5 RNA in snRNPs reconstituted in vitro revealed five contacting
proteins, Prp8p, Snu114p, p30, p16, and p10, contact by the three smaller
proteins requiring an intact Sm site. Site-specific crosslinking showed that
Snu114p contacts the 5' side of internal loop 1, whereas Prp8p interacts with
five different regions of the 5' stem-loop, but not with the Sm site or 3' stem
loop. Both internal loops in the 5' domain are essential for Prp8p to associate
with the snRNP, but the conserved loop 1 is not, although this is the region to
which Prp8p crosslinks most strongly. The extensive contacts between Prp8p and
the 5' stem-loop of U5 RNA support the hypothesis that, in spliceosomes, Prp8p
stabilizes loop 1-exon interactions. Moreover, data showing that Prp8p contacts
the exons even in the absence of loop 1 indicate that Prp8p may be the principal
anchoring factor for exons in the spliceosome. This and the close proximity of
the spliceosomal translocase, Snu114p, to U5 loop 1 and Prp8p support and extend
the proposal that Snu114p mimics U5 loop 1 during a translocation event in the
spliceosome.
PMID- 9769099
TI - Cryoenzymology of the hammerhead ribozyme.
AB - The technique of cryoenzymology has been applied to the hammerhead ribozyme in an
attempt to uncover a structural rearrangement step prior to cleavage. Several
cryosolvents were tested and 40% (v/v) methanol in water was found to perturb the
system only minimally. This solvent allowed the measurement of ribozyme activity
between 30 and -33 degrees C. Eyring plots are linear down to -27 degrees C, but
a drastic reduction in activity occurs below this temperature. However, even at
extremely low temperatures, the rate is still quite pH dependent, suggesting that
the chemical step rather than a structural rearrangement is still rate-limiting.
The nonlinearity of the Eyring plot may be the result of a transition to a cold
denatured state or a glassed state.
PMID- 9769100
TI - The RNA recognition motif of yeast translation initiation factor Tif3/eIF4B is
required but not sufficient for RNA strand-exchange and translational activity.
AB - The Saccharomyces cerevisiae TIF3 gene encodes a 436-amino acid (aa) protein that
is the yeast homologue of mammalian translation Initiation factor eIF4B. Tif3p
can be divided into three parts, the N-terminal region with an RNA recognition
motif (RRM) (aa 1-182), followed in the middle part by a sevenfold repeat of 26
amino acids rich in basic and acidic residues (as 183-350), and a C-terminal
region without homology to any known sequence (aa 351-436). We have analyzed
several Tif3 proteins with deletions at their N and C termini for their ability
(1) to complement a tif3delta strain in vivo, (2) to stimulate Tif3-dependent
translation extracts, (3) to bind to single-stranded RNA, and (4) to catalyze RNA
strand-exchange in vitro. Here we report that yeast Tif3/eIF4B contains at least
two RNA binding domains able to bind to single-stranded RNA. One is located in
the N-terminal region of the protein carrying the RRM, the other in the C
terminal two-thirds region of Tif3p. The RRM-containing domain and three of the
seven repeat motifs are essential for RNA strand-exchange activity of Tif3p and
translation in vitro and for complementation of a tif3delta strain, suggesting an
important role for RNA strand-exchange activity in translation.
PMID- 9769101
TI - Spb4p, an essential putative RNA helicase, is required for a late step in the
assembly of 60S ribosomal subunits in Saccharomyces cerevisiae.
AB - Spb4p is a putative ATP-dependent RNA helicase that is required for synthesis of
60S ribosomal subunits. Polysome analyses of strains genetically depleted of
Spb4p or carrying the cold-sensitive spb4-1 mutation revealed an
underaccumulation of 60S ribosomal subunits. Analysis of pre-rRNA processing by
pulse-chase labeling, northern hybridization, and primer extension indicated that
these strains exhibited a reduced synthesis of the 25S/5.8S rRNAs, due to
inhibition of processing of the 27SB pre-rRNAs. At later times of depletion of
Spb4p or following transfer of the spb4-1 strain to more restrictive
temperatures, the early pre-rRNA processing steps at sites A0, Al, and A2 were
also inhibited. Sucrose gradient fractionation showed that the accumulated 27SB
pre-rRNAs are associated with a high-molecular-weight complex, most likely the
66S pre-ribosomal particle. An HA epitope-tagged Spb4p is localized to the
nucleolus and the adjacent nucleoplasmic area. On sucrose gradients, HA-Spb4p was
found almost exclusively in rapidly sedimenting complexes and showed a peak in
the fractions containing the 66S pre-ribosomes. We propose that Spb4p is involved
directly in a late and essential step during assembly of 60S ribosomal subunits,
presumably by acting as an rRNA helicase.
PMID- 9769102
TI - Metal ion probing of rRNAs: evidence for evolutionarily conserved divalent cation
binding pockets.
AB - Ribosomes are multifunctional RNP complexes whose catalytic activities absolutely
depend on divalent metal ions. It is assumed that structurally and functionally
important metal ions are coordinated to highly ordered RNA structures that form
metal ion binding pockets. One potent tool to identify the structural
surroundings of high-affinity metal ion binding pockets is metal ion-induced
cleavage of RNA. Exposure of ribosomes to divalent metal ions, such as Pb2+,
Mg2+, Mn2+, and Ca2+, resulted in site-specific cleavage of rRNAs. Sites of
strand scission catalyzed by different cations accumulate at distinct positions,
indicating the existence of general metal ion binding centers in the highly
folded rRNAs in close proximity to the cleavage sites. Two of the most efficient
cleavage sites are located in the 5' domain of both 23S and 16S rRNA, regions
that are known to self-fold even in the absence of ribosomal proteins. Some of
the efficient cleavage sites were mapped to the peptidyl transferase center
located in the large ribosomal subunit. Furthermore, one of these cleavages was
clearly diminished upon AcPhe-tRNA binding to the P site, but was not affected by
uncharged tRNA. This provides evidence for a close physical proximity of a metal
ion to the amino acid moiety of charged tRNAs. Interestingly, comparison of the
metal ion cleavage pattern of eubacterial 70S with that of human 80S ribosomes
showed that certain cleavage sites are evolutionarily highly conserved, thus
demonstrating an identical location of a nearby metal ion. This suggests that
cations, bound to evolutionarily constrained binding sites, are reasonable
candidates for being of structural or functional importance.
PMID- 9769103
TI - Correlation between bending of the VM region and pathogenicity of different
Potato Spindle Tuber Viroid strains.
AB - Only 40 of the 359 nucleotides of Potato Spindle Tuber Viroid (PSTVd) represent
the virulence-modulating (VM) region. Minor sequence variations in this domain
distinguish mild from severe and even necrotic strains. Our recent hypothesis
(Owens RA et al., 1996, Virology 222:144-158) that these differences result in
varying degrees of bending of this part of the molecule could be tested
experimentally. By in vitro transcription and partial double-strand formation,
three types of model RNAs were prepared and subjected to electrophoresis in
polyacrylamide gels: (1) Fragments representing the VM regions of six different
PSTVd strains; (2) control fragments containing a bulge-loop as a rigid bend or
an internal loop as a point of increased flexibility; and (3) dsRNAs of 36, 39,
and 43 bp as length standards. Migration anomalies in gels of increasing
percentage were evaluated and resulted in the following conclusions. In the
absence of Mg2+, the VM regions differ only in terms of flexibility. Addition of
Mg2+ induces conformational changes in these RNAs. All strains but Mild exhibit a
rigid bend, and the angle of bending increases monotonically with the
pathogenicity of the strain. The data are discussed in terms of a mechanism of
pathogenicity, that protein-binding to the VM region is the primary pathogenic
event.
PMID- 9769104
TI - Identification and functional analysis of hPRP17, the human homologue of the
PRP17/CDC40 yeast gene involved in splicing and cell cycle control.
AB - The PRP17 gene of the yeast Saccharomyces cerevisiae encodes a protein that
participates in the second step of the splicing reaction. It was found recently
that the yeast PRP17 gene is identical to the cell division cycle CDC40 gene. The
PRP17/CDC40 gene codes for a protein with several copies of the WD repeat, a
motif found in a large family of proteins that play important roles in signal
transduction, cell cycle progression, splicing, transcription, and development.
In this report, we describe the identification of human, nematode, and fission
yeast homologues of the PRP17/CDC40 gene of S. cerevisiae. The newly identified
proteins share homology with the budding yeast protein throughout their entire
sequence, with the similarity being greatest in the C-terminal two thirds that
includes the conserved WD repeats. We show that a yeast-human chimera, carrying
the C-terminal two thirds of the hPRP17 protein, is able to complement the cell
cycle and splicing defects of a yeast prp17 mutant. Moreover, the yeast and yeast
human chimeric proteins co-precipitate the intron-exon 2 lariat intermediate and
the intron lariat product, providing evidence that these proteins are spliceosome
associated. These results show the functional conservation of the Prp17 proteins
in evolution and suggest that the second step of splicing takes place by a
similar mechanism throughout eukaryotes.
PMID- 9769105
TI - T7 RNA polymerase produces 5' end heterogeneity during in vitro transcription
from certain templates.
AB - The use of T7 RNA polymerase to prepare large quantities of RNA of a particular
sequence has greatly facilitated the study of both the structure and function of
RNA. Generally, it has been believed that the products of this technique are
highly homogeneous in sequence, with only a few noted exceptions. We have
carefully examined the transcriptional products of several tRNAs that vary in
their 5' end sequence and found that, for those molecules that begin with
multiple, consecutive guanosines, the transcriptional products are far from
homogenous. Although a template beginning with GCG showed no detectable 5' end
heterogeneity, two tRNA templates designed to have either four or five
consecutive guanosines at their 5' ends had more than 30% of their total
transcriptional products extended by at least one untemplated nucleotide at their
5' end. By simply reducing the number of consecutive guanosines, the
heterogeneity was reduced significantly. The presence of this 5' end
heterogeneity in combination with the 3' end heterogeneity common to T7
transcriptions results in a mixture of RNA molecules even after rigorous size
purification.
PMID- 9769106
TI - Biomarkers in toxicology.
AB - The use of biomarkers in toxicology is becoming increasingly important. This
article briefly reviews some of the aspects in an attempt to give an overall view
of the field. Some of the new developments, particularly in relation to
biomarkers of exposure and response, are mentioned. Specific DNA and protein
adducts can now be used as biomarkers of the effective exposure so incorporating
variations in environmental levels and individual disposition. Analysis of
urinary metabolite profiles by NMR can highlight novel markers and allow
recognition of patterns of metabolite changes as biomarkers of a toxic response.
Novel urinary markers for liver and testicular dysfunction are discussed.
Finally, the acetylator phenotype as a biomarker of susceptibility is described.
PMID- 9769107
TI - Experimental studies on immunosuppression: how do they predict for man?
AB - The ultimate goal of any animal model in immunotoxicity testing is that it be a
sensitive predictor of xenobiotic-induced immune dysfunction in humans. Such
models should be capable of identifying the target(s) within the immune system
affected by the xenobiotic. In particular the tier testing models have been
successfully used to identify and characterize a variety of different
immunotoxicants in animals as it pertains to immunosuppression and reduced
resistance to infectious diseases. These tier models in mice and rats have been
validated in interlaboratory studies. Although these protocols were designed for
studies of rats and mice, some have been applied successfully for studying
immunotoxicity in other animal species, including non-human primates. A great
amount of data has been generated by the application of these models, which
demonstrate that xenobiotics alter the immune system of animals. In man, the
database on chemical-induced immunosuppression is limited, as the use of markers
of immunotoxicity has received little attention in clinical and epidemiological
studies. Such studies have not been performed frequently, and their
interpretation often does not permit unequivocal conclusions to be drawn, due for
instance to the presence of confounding factors and the uncontrolled nature of
exposure. Also, testing possibilities in humans are limited and immune function
changes by chemical exposure are often subtle. In humans, a number of agents have
been shown to have immunosuppressive properties (including PCBs, PCDDs, PCDFs,
oxidant gases, and ultraviolet radiation), but the strongest evidence stems from
the clinical use of immunosuppressant drugs in transplant patients. These human
data do in general terms confirm the data gained with experimental animals.
Immunotoxicity assessment in rodents therefore adequately forms the basis for
human risk assessment. Knowledge on the predictability of these animal models and
immune assays can be further improved by comparison of the human and animal data
obtained in the development of drugs.
PMID- 9769108
TI - Value of animal models for predicting hypersensitivity reactions to medicinal
products.
AB - Although hypersensitivity reactions induced by medicinal products and chemicals
are relatively common, few predictive models are available. A major difficulty is
our currently limited understanding of the mechanisms involved, and efforts
should be paid to better defining drug immunogenicity, hapten formation and
immune effector mechanisms. A second difficulty is the multiplicity of clinical
manifestations presumably due to varying mechanisms. Available models can only
predict a few of these reactions. Anaphylaxis models in guinea-pigs can be only
used for the safety assessment of macromolecules which are neither humanized or
of human origin, whereas guinea-pig or mouse models can detect the majority of
human contact sensitizers. In addition to the extensive validation of existing
models, promising avenues of research are expected to be found in the use of
novel animal models, particularly those using genetically modified animals, such
as transgenic and knock-out mice.
PMID- 9769109
TI - Epidemiology studies in immunotoxicity evaluations.
AB - Studies in humans designed to detect immunomodulation from exposure to
xenobiotics present challenging problems to epidemiologists and
immunotoxicologists. Exposed and control groups must be carefully selected,
exposure to the xenobiotic must be sufficiently high and well-documented, and the
referent group should be as similar as possible to the exposed. Immune
markers/functional tests in an individual may be influenced by sunlight exposure,
medication, illness and use of recreational drugs; all of these potential
confounding factors must be addressed. Sample acquisition is usually performed at
sites geographically distant from the controlled environment of an investigator's
laboratory, yielding an assortment of new problems that would not occur in
clinical or hospital situations. Regulations and guidelines concerning the
transport of biological samples and potential hazards of HIV and HBV exposures to
personnel must be adapted to field conditions. Since the application of
immunotoxicological techniques to populations exposed to xenobiotics is
relatively new, and the ability to measure an increasing number of immune
biomarkers of activation, suppression, autoimmunity or hypersensitivity is
rapidly expanding, there are difficulties in the interpretation of statistically
positive results (sometimes within the normal range) and their potential health
significance. Finally, both biological and methodological factors complicate the
assessment of dose-response/concentration effect relationships in human
immunotoxicity studies, and traditional dose-response relationships may not
always be present.
PMID- 9769110
TI - Cytokine assays in human sera and tissues.
AB - The use of accurate and sensitive methods for the measurement of cytokines in
body fluids is an absolute prerequisite for the proper use of these mediators in
clinical practice. Many factors contribute to the complexity of cytokines
quantitation: these molecules circulate at very low levels (e.g. pg/ml) under
various molecular forms, the existence of circadian rhythms has been described,
and the presence of inhibitors (binding proteins, soluble receptors,
autoantibodies) can potentially interfere in the assays. Blood collection for
cytokines needs particular attention to prevent possible contamination by
endotoxins, which can trigger cytokines cellular production after sampling.
Bioassays historically preceded immunoassays; the latter techniques are now very
popular, but there is an urgent need for standardisation between the different
kits commercially available. Nevertheless, due to the essentially local effects
of cytokines, the study of their circulating levels only represents the 'tip of
the iceberg' and is of limited value for a global understanding of the
pathophysiology of these mediators. This explains the development of other
approaches to assess the ability of cells to produce cytokines. These include the
ELISPOT assay, the measurement of cell-associated cytokines by flow cytometry,
and the study of cytokine secretion by isolated peripheral blood mononuclear
cells or by whole blood test. All these techniques, associated with a local
detection of cytokines by immunohistochemistry or in situ hybridization and
reverse transcriptase polymerase chain reaction (RT-PCR), appear to be
complementary tools for a better understanding of the multiple aspects of the
biology of cytokines.
PMID- 9769111
TI - Biomarkers of immunotoxicity in fish and other non-mammalian sentinel species:
predictive value for mammals?
AB - Through the efforts of different laboratories, a battery of immunological assays
is available to predict the immunotoxicity of xenobiotics. These assays,
originally developed in rodents, have been adapted for use in a variety of animal
species and are now used routinely in these models to assess the immunotoxicity
of different chemical classes. For example, our laboratory has employed assays
that measure antibody-forming cell response to T-dependent antigens, T- and B
cell lymphoproliferation, macrophage function, and host resistance against
infectious bacteria to assess metal-induced immunotoxicity in laboratory-reared
Japanese medaka (Oryzias latipes); immunologically-related assays measuring
antioxidant activity have also been used in this capacity. Results of the
aforementioned investigations have shown the usefulness of these endpoints to
reliably demonstrate chemical-mediated immunotoxicity in teleost systems. Many of
these same endpoints have also proved successful for predicting the immunotoxic
effects of contaminated aquatic environments in feral fish populations. For
example, smallmouth bass collected from a chlorinated hydrocarbon-contaminated
site demonstrated significant changes in blood cell profiles and kidney phagocyte
function compared to fish collected from a 'clean water' reference site. Some of
these same immune parameters have also been used successfully to predict the
immunotoxicity of polluted aquatic environments in feral populations of fish
eating birds and harbor seals. While interspecies extrapolation is difficult and
should be approached with caution due to variables such as metabolism and
pharmacokinetics, results from these studies demonstrate the usefulness of these
immune assays to predict the immunomodulating effects of xenobiotics in fish and
other wildlife species, as well as the applicability of fish to serve as
additional/alternate animal models for mammalian species in immunotoxicological
studies.
PMID- 9769112
TI - Application of immunologic methods in clinical trials.
AB - Immunologic effects of a new pharmaceutical molecule are often studied by in
vitro immune assays and in laboratory animal models. However, immunologic
activity can also be evaluated in man during the early clinical stage of drug
development. Measures of immunologic response have recently served as surrogate
clinical endpoints for drug approval. A variety of non-invasive measures can
determine if a test molecule enhances or suppresses immunity. Both antibody and
cellular immune responses to a new molecule itself can be detected and quantified
in man. Assuring the successful outcome of a clinical trial incorporating
immunologic parameters however, requires a realistic approach to protocol
development, care in site selection, and a critical evaluation of participating
laboratories.
PMID- 9769113
TI - Results of a cyclosporin A ringstudy.
AB - The aim of the study was to find out whether an extended subacute toxicity study
(additional organ weights, histopathology and immune functional tests), routinely
employed in testing of chemicals, would shown indications of (adverse) effects on
the immune system below general toxicity. Therefore, a five laboratory ring study
on the basis of an oral 28-day repeated dose study in rats (OECD guideline 407)
was carried out with 1, 5 and 25 mg/kg of cyclosporin A (CsA) per day by gavage.
Besides some toxic effects such as reduced body weight gain and increased kidney
calcification in the high-dose group, the results of the additional pathologic
examinations revealed that CsA caused a pattern of specific morphological
alterations of the lymphoid tissues in mid- and high-dose groups. Selected immune
parameters such as immunoglobulin determination, plaque-forming assay, flow
cytometry, activation status of macrophages and natural killer cells (NK), and
proliferative response of spleenocytes and cells from mesenteric lymph nodes
(concanvalin A (ConA) and pokeweed mitogen (PWM) stimulation) were also
investigated. Some results compared to the controls revealed alterations down to
the low-dose group. The extended methodology consistently indicated the potential
detection of effects on the immune system below general systemic toxicity. The
study will be continued by investigating a second compound with primarily
immunostimulating effects. Results from those studies should further contribute
to the current discussion of up-dating of repeated dose toxicity guidelines with
respect to immunotoxicity.
PMID- 9769114
TI - T cell-tumor cell: a fatal interaction?
AB - Fas (Apo-1/CD95) is a cell-surface protein that is responsible for initiating a
cascade of proteases (caspases) culminating in apoptotic cell death in a variety
of cell types. The function of the Fas/FasL system in the dampening of immune
responses to infectious agents through the autocrine deletion of activated T
cells has been well documented. More recently, it has been proposed that tumor
cells express FasL, presumably to avoid immune detection. In this review, we
focus on the role of the interaction of Fas and FasL in the modulation of
antitumor responses. We critically examine the evidence that FasL is expressed by
tumor cells and explore alternative explanations for the observed phenomena in
vitro and in vivo. By reviewing data that we have generated in our laboratory as
well as reports from the literature, we will argue that the Fas/FasL system is a
generalized mechanism used in an autocrine fashion to regulate cell survival and
expansion in response to environmental and cellular cues. We propose that FasL
expression by tumor cells, when present, is indicative of a perturbed balance in
the control of proliferation while "immune privilege" is established by "suicide"
of activated antitumor T cells, a form of activation-induced cell death.
PMID- 9769115
TI - Irradiated tumor cells adenovirally engineered to secrete granulocyte/macrophage
colony-stimulating factor establish antitumor immunity and eliminate pre-existing
tumors in syngeneic mice.
AB - The specific aim of this study was to examine the prophylactic as well as the
therapeutic efficacies of irradiated mouse CT26 colon cancer cells, infected with
recombinant adenoviruses harboring cDNAs specific for granulocyte macrophage
colony-stimulating factor (GM-CSF), interferon (IFN-gamma) and monocyte
chemotactic protein1 (MCP-1). Results showed that tumor cells secrete the
respective cytokines for several days after infection and subsequent irradiation.
Vaccination with irradiated GM-CSF-secreting CT26 cells protected 90% of
syngeneic mice challenged with live parental cells. On the other hand,
vaccination with irradiated IFNgamma or MCP-1-secreting CT26 cells totally failed
to protect mice from tumor development after challenge with parental cells. None
of the tumor-free mice initially vaccinated with irradiated GM-CSF-producing CT26
cells developed tumor upon repeated challenge with parental cells during the
entire observation period. The establishment of specific and long-lasting
antitumor immunity following vaccination with GM-CSF-producing tumor cells
requires the simultaneous presence of GM-CSF and tumor antigen at the vaccine
site. Depletion of CD8+ cells, but not CD4+ cells, blocked the vaccine efficacy
of GM-CSF-producing tumor cells. Subcutaneous injection of irradiated GM-CSF
producing CT26 cells also effectively prevented the growth of a small load of
parental tumor that was implanted 3 days earlier or the development of metastatic
foci in the lung from intravenously injected parental cells either 7 days before
or 3 days after vaccination. Our data thus show that, in these experimental tumor
models, subcutaneous injection of irradiated tumor cells adenovirally, transduced
with the GM-CSF gene leads not only to prevention of growth of subsequently
implanted tumor but also to elimination of pre-existing and metastatic tumors.
PMID- 9769116
TI - In vitro propagated dendritic cells from patients with human-papilloma virus
associated preneoplastic lesions of the uterine cervix: use of Flt3 ligand.
AB - Dendritic cells (DC) are the most efficient antigen presenting cells. The
clinical use of DC as vectors for antitumor and anti-infectious disease
immunotherapy has been limited by their low level and accessibility in normal
tissue. Substantial numbers of DC can be generated from peripheral blood cultured
in the presence of interleukin-4 (IL-4) and granulocyte/macrophage-colony
stimulating factor (GM-CSF). We showed in this study that substantial numbers of
DC can be obtained from the peripheral blood of patients with (pre)neoplastic
lesions of the uterine cervix. The procedure required relatively small blood
samples (10 ml) and the presence of 100 U/ml IL-4 and 800 U/ml GM-CSF in the
culture medium. There was no significant difference in the morphology, yield,
phenotype and function of generated DC between patients with cervical
(pre)neoplastic lesions and healthy individuals. When the hematopoietic factor
Flt3 ligand (Flt3L, 40 ng;ml) was added, there was an average increase in the DC
population of 26% compared to cultures with GM-CSF and IL-4 alone. Approximately
1.2 x 10(6) cells with the characteristics of dendritic cells could be obtained
when Flt3L was included in the medium. The addition of Flt3L did not modify the
phenotypic profile of DC (HLA-DR+, CD1a+, CD4+, CD54+, CD80+, CD86+. CD40+, CD3-
and CD14-). In addition, Flt3L generated functional DC capable of stimulating the
proliferation of alloreactive T cells. These results suggest that Flt3L, in
association with GM-CSF and IL-4, provides an advantageous tool for the large
scale generation of DC and that an immunotherapy based on the use of DC generated
in vitro is possible in patients with (pre)neoplastic lesions of the uterine
cervix.
PMID- 9769117
TI - In vitro induction of HLA-A2402-restricted and carcinoembryonic-antigen-specific
cytotoxic T lymphocytes on fixed autologous peripheral blood cells.
AB - HLA-A2402-restricted and carcinoembryonic-antigen(CEA)-specific cytotoxic T
lymphocytes (CTL) were induced by culturing human peripheral blood mononuclear
cells (PBMC) on formalin-fixed autologous adhesive PBMC that had been loaded with
CEA-bound latex beads. The CTL killed the CEA-producing HLA-type matched cancer
cells, but not the non-producers of CEA, at an effector/target ratio of 10 within
24 h. On the basis of available HLA-A24-binding peptides, we have also attempted
to identify the epitope peptide recognized by the CTL. The peptide CEA652(9),
TYACFVSNL, stimulated the CTL most strongly when pulsed on HLA-A2402-expressing
target cells. The other nine peptides so far tested were also active, but less
efficient in their effect on CTL. The CTL failed to kill target cells pulsed with
the HLA-A2-binding CEA peptide, CAP-1. The CTL were also generated on the fixed
adherent cells previously pulsed with the peptide CEA652(9). Cytotoxic activity
of the CTL was inhibited by monoclonal antibodies against CD3, CD8, and MHC class
I molecules. These results suggest that human autologous CTL will be inducible on
the autologous fixed PBMC without use of the cultured target cancer cells if
tumor antigenic protein is available.
PMID- 9769118
TI - Interleukin-15 effectively potentiates the in vitro tumor-specific activity and
proliferation of peripheral blood gammadeltaT cells isolated from glioblastoma
patients.
AB - GammadeltaT cells play a regulatory role in both primary and metastatic tumor
growth in humans. The mechanisms responsible for the activation and proliferation
of circulating gammadeltaT cells should be fully understood prior to their
adoptive transfer to cancer patients. We have examined in vitro functional
effects of interleukin-15 (IL-15) on highly purified gammadeltaT cells isolated
from glioblastoma patients. GammadeltaT cells constitutively express the
heterotrimeric IL-2 receptor (IL-2R) alpha betagamma, but the levels of IL-2Rbeta
or gamma expression were not increased by incubation with saturating amounts of
IL-15. IL-15 was shown to induce a maximal gammadeltaT cell proliferation,
although at much higher concentrations (at least 2000 U/ml) than IL-2 (100 U/ml).
Submaximal concentrations of IL-15 plus low concentrations of IL-2 produced an
additive proliferative response. In contrast to the IL-2-induced response, this
activity was completely or partially abrogated by anti-IL-2Rbeta, or anti-IL
2Rgamma antibodies, but not by anti-IL-2R alpha antibodies. Incubation of
gammadeltaT cells in the presence of IL-15 resulted not only in the appearance of
NK and LAK activity, but also in specific autologous tumor cell killing activity,
an additive effect being seen with IL-15 and IL-2. This IL-15-induced tumor
specific activity could be significantly blocked by anti-IL-2Rgamma and anti-IL
2R-beta mAb, but not by anti-IL-2R alpha mAb. Thus, in contrast to IL-2, IL-15
activates tumor-specific gammadeltaT cells through the components of IL-2Rbeta
and IL-2Rgamma, but not IL-2R alpha. These enhanced in vitro tumor-specific and
proliferative responses of gammadeltaT cells seen with IL-15 suggest a rational
adjuvant imunotherapeutic use of gammadeltaT cells in cancer patients.
PMID- 9769119
TI - CD40-ligation-mediated protection from apoptosis of a Fas-sensitive Hodgkin's
disease-derived cell line.
AB - Modulation of Fas expression and function by CD40 ligation was investigated in
the Fas-sensitive human Hodgkin's disease cell line HDLM2. The recombinant human
trimeric soluble CD40L (sCD40L) protected this cell line from apoptosis induced
by an agonistic Fas antibody at all concentrations tested. sCD40L also protected
HDLM2 when added up to 2 h after Fas ligation. Apoptosis induced by a cell
permeable synthetic ceramide could not be prevented by sCD40L. Thus, CD40
ligation is likely to intervene in the early phases of the Fas signal
transduction pathway. When CD40 ligation preceded Fas ligation, it rendered the
cells refractory to Fas-induced apoptosis. sCD40L-mediated protection could not
be attributed to reduction in surface Fas expression, increase in Bcl-2 levels or
to increase in the levels of soluble Fas isoforms.
PMID- 9769120
TI - Unresponsiveness to interferon associated with STAT1 protein deficiency in a
gastric adenocarcinoma cell line.
AB - HC class I expression can be up-regulated by interferons (IFN) and other
cytokines. Both IFNalpha and IFNgamma have been shown to exert their effects via
a recently discovered signalling pathway by inducing tyrosine phosphorylation of
their receptors. Receptors for interferons and other cytokines signal through the
action of associated protein tyrosine kinases of the JAK family (Janus kinase)
and latent cytoplasmic transcriptional activators from the STAT family (signal
transducers and activators of transcription). Here we report a gastric
adenocarcinoma cell line, AGS, that is defective in its response to either
IFNalpha or IFNgamma. AGS cells display selective alterations only in MHC class I
inducibility and not in constitutive MHC class I expression. In nuclear extracts
of AGS cells, no binding activity to interferon-responsive elements (GAS/ISRE)
was observed. We found that AGS cells showed an extremely low level of STAT1
expression, which may be responsible for the absence of biological response to
IFN. Because STAT1-deficient cells are highly sensitive to infection by virus,
the absence of these proteins may also contribute to the tumor phenotype, giving
the tumor a selective advantage, by inhibiting cell growth suppression mediated
by IFN and abetting escape from the T cell antitumor response.
PMID- 9769121
TI - Morphogenetic concepts of normal and abnormal growth in the human prostate.
AB - Benign prostatic hyperplasia (BPH) and prostate cancer are multifactorial disease
processes, involving a growing number of biochemical, genetic and epigenetic
factors. Their pathogenesis, however, remains poorly understood. The present
review examines current morphogenetic concepts of normal and abnormal growth in
the human prostate. This includes the role of basal cells in organogenesis and
cancerogenesis, the impact of cell-matrix interactions, and the importance of
cellular heterogeneity in tumour progression and hormone-insensitive growth.
Knowledge of morphogenesis and morphology is required in any scientific approach
to BPH and prostate cancer.
PMID- 9769122
TI - Primary hereditary medullary thyroid carcinoma--C-cell morphology and correlation
with preoperative calcitonin levels.
AB - Early thyroidectomy offers an opportunity of preventing the development of
medullary thyroid carcinoma (MTC) in patients at risk for hereditary MTC. We
investigated the thyroid glands of 32 patients with hereditary MTC to identify
the changes in C-cell morphology and to correlate these with plasma calcitonin
(CT) levels and with clinical data. The entire thyroid gland was processed for
histological examination including immunostaining for CT. All glands revealed C
cell hyperplasia (CCH), and MTC was found in 21 patients (66% of 32, youngest
patient 6 years, youngest with lymph node metastases [LNM] 17 years). The
transition from CCH to MTC was characterized by destruction of the follicular
basement membrane and by diminished intensity of CT immunostaining. Normal plasma
CT levels after provocation with pentagastrin were found only in patients with
CCH. Basally elevated plasma CT levels were restricted to MTC. LNM were only
found in multifocal tumours at least 4 mm in diameter. It is not yet clear
whether or not CCH in patients at risk for hereditary MTC is a neoplastic change,
but in these patients the term 'C-cell hyperplasia' is of doubtful value. All MEN
gene carriers reveal CCH, and almost all of them will develop multifocal MTC, so
that CCH is probably a precursor lesion of an indubitably malignant tumour.
Prophylactic thyroidectomy is justified at the age of 6 to anticipate development
of a MTC. Lymphadenectomy is necessary in children if they are older than 10
years or have elevated plasma CT levels.
PMID- 9769123
TI - "Atypical" medullary thyroid carcinoma with little or no calcitonin expression.
AB - In a retrospective analysis of 142 medullary thyroid carcinomas, four sporadic
cases with an unusual histological and immunohistochemical appearance were found.
Three cases (two males, one female) had very few calcitonin-positive tumour
cells, while the fourth case (male) completely lacked calcitonin immunoreactivity
at both mRNA and protein levels, whereas a variety of neuroendocrine markers were
positive in at least 50% of tumour cells. The four tumours were completely devoid
of carcinoembryonic antigen expression and of amyloid. Differential diagnosis and
histogenetic considerations are discussed.
PMID- 9769124
TI - Diagnostic cytological features of neuroendocrine differentiated carcinoma of the
breast.
AB - Neuroendocrine (NE) features characterize a minority of carcinomas of the breast
corresponding to definite subtypes, which cover a wide spectrum of
differentiation. Breast metastases from NE tumours of gastrointestinal origin are
not rare, and to determine whether NE carcinomas in the breast could be
differentiated from other tumours on fine needle aspiration (FNA) we analysed the
cytological features of 13 primary NE breast carcinomas of different types (7
carcinoid-like, 5 mucinous and 1 solid spindle cell). Smears of carcinoid-like
carcinomas showed specific features that made it possible to differentiate them
from other primary tumours, but not from breast metastases of NE carcinomas.
These features were: cell clusters with rigid borders, single cells with a
plasmacytoid appearance and peripheral cytoplasmic granules evident on Giemsa
staining and immunoreactive for chromogranin A. In mucinous NE carcinomas such
granules were less apparent, and the cytological features could have been
mistaken for those of fibroadenomas, as in the case of non-NE mucinous
carcinomas. The solid spindle cell type showed noncohesive fusiform cells and
moderate nuclear pleomorphism, a pattern similar to that of atypical carcinoids
of the lung.
PMID- 9769125
TI - Expression of cyclin Ds in relation to p53 status in human breast carcinomas.
AB - Cyclin D1 has been reported to be overexpressed in many tumours, including breast
carcinomas. Cyclin D1 was first identified as a protooncogene (BCL1/PRAD1), and
its overexpression was related to tumour proliferation. The product has also
recently been identified as important in mediating cell cycle growth arrest via
the p53 pathway in murin fibroblast cell lines. Ninety breast carcinomas
previously analysed for p53 status were analysed for amplification of cyclin D1,
D2 and D3 genes by Southern blot analysis and for protein expression by
immunhistochemistry. In 10 samples gene amplification was detected at the cyclin
D1 locus. No gene amplification was detected at the cyclin D2 and D3 loci.
Immunoreactivity for cyclin D1 was detected in 38 (42.2%) tumour tissue samples.
Fifty samples were immunostained for cyclin D2 and D3. Only 2 samples (4%) showed
immunoreactivty for cyclin D2, and 9 samples (18%) for cyclin D3. Cyclin D1
protein overexpression was significantly more often found in tumours with wild
type p53 and in tumours with higher grades of differentiation expressing ER. No
association was seen between gene amplification of the cyclin D1 gene and p53
status. We conclude there is a relationship between wild type p53 and cyclin D1
protein overexpression in clinical material, indicating that cyclin D1 may be
another downstream effector of p53.
PMID- 9769126
TI - Bcl-2 expression in male breast carcinoma.
AB - We have analysed the expression of bcl-2 protein retrospectively in 34 primary
male breast carcinomas (MBC), using the monoclonal antibody bcl-2 in formalin
fixed, paraffin-embedded tissues. Bcl-2 expression was compared with tumour
clinicopathological features, sex steroid hormone receptors, DNA content, p53
immunoreactivity and cell proliferative activity assessed by counts of the
argyrophilic nucleolar organizer regions (AgNORs), the monoclonal antibody PC10
against proliferating cell nuclear antigen and the monoclonal antibody MIB-1.
Most (28, or 82.3%) of the 34 cases of MBC were bcl-2 positive. No association
was found with clinicopathological features of the tumours, although bcl-2 tended
to be more frequently expressed in small tumours (P=0.09) and in cases without
necrotic areas (P=0.1). Nor was any association found with hormone receptor
status, p53 immunoreactivity, DNA content, cell proliferative activity or patient
survival. In multivariate analysis, only proliferative activity (expressed by
AgNOR counts) and p53 immunoreactivity had independent prognostic significance.
Our results indicate that MBC differs from FBC in that in MBC bcl-2 protein is
not related to an oestrogen-dependent transcription pathway and bcl-2 alone is
not sufficient to induce increased proliferation. These characteristics, together
with the high prognostic value of cell proliferation and the lack of prognostic
significance for hormone receptor status, support the hypothesis that MBC is
biologically different from FBC.
PMID- 9769127
TI - The retroperitoneal resection margin and vessel involvement are important factors
determining survival after pancreaticoduodenectomy for ductal adenocarcinoma of
the head of the pancreas.
AB - The prognosis of ductal adenocarcinoma of the pancreas is still poor. We analysed
the factors that have a major influence on the survival of patients. Surgical
specimens from 51 patients with ductal adenocarcinoma of the head of the pancreas
were examined for tumour size, histological type, grade and local extension. In 7
patients the retroperitoneal resection margin was involved either macroscopically
or histologically. Their mean survival was 10.6 months (1-17 months), compared
with 22.7 months for the 44 patients with curative R0 resection. In 10 patients
large vessels (portal and/or mesenteric vein) had to be resected; they survived
for only 2-11 months, with a mean of 5 months (P<0.05). Non-R0-resected patients
and patients in whom tumour-invaded vessels had to be resected constitute a high
risk group with a significantly shorter mean survival of 8.8 months, compared
with 24.3 months for R0 resected patients without vessel invasion (P<0.05). Lymph
node metastases were seen in 35 of 51 patients. Survival analysis based on nodal
status revealed a mean survival of 33 months for patients staged as N0, 21.4 for
N1a patients and 14 month for N1b patients. The differences were not
statistically significant, however. Our data suggest that tumour invasion of the
retroperitoneal resection margin and large vessel involvement are the major
factors determining survival in patients with pancreatic cancer.
PMID- 9769128
TI - TPA-induced cohort migration of well-differentiated human rectal adenocarcinoma
cells: cells move in a RGD-dependent manner on fibronectin produced by cells, and
phosphorylation of E-cadherin/catenin complex is induced independently of cell
extracellular matrix interactions.
AB - We have already presented a two-dimensional cell motility assay using a highly
metastatic variant (L-10) of human rectal adenocarcinoma cell line RCM-1 as a
motility model of tumour cells of epithelial origin. In this model, L-10 cells
showed locomotion as a coherent sheet when stimulated with 12-O
tetradecanoylphorbol-13-acetate (TPA), and we called this type of movement
"cohort migration". Electron and immunoelectron microscopic study of the
migrating cell sheets demonstrated localized release from cell-cell adhesion only
at the lower portion of the cells with loss of E-cadherin immunoreactivity, and
this change was associated with increased tyrosine phosphorylation of the E
cadherin-catenin complex, including beta-catenin. Cell-extracellular matrix (ECM)
interactions involved in this TPA-induced cohort migration and their effect on
tyrosine phosphorylation of the E-cadherin-catenin complex have now been
investigated. L-10 cell cohort migration was almost completely inhibited by
addition of Arg-Gly-Asp (RGD) peptide into the medium, and thus RGD dependent.
Cohort migration was stimulated on type I and IV collagens, fibronectin (FN)- and
laminin-coated substratum, but was inhibited by RGD only on FN-coated surface. By
using immunofluorescent techniques, FN was demonstrated preferentially around
migrating cells, and a protein synthesis inhibitor, cycloheximide, inhibited the
migration by about 75%. FN produced by L-10 cells were found to be mostly EDA+ FN
when analysed by RT-PCR. Moreover, anti-FN antibody, but not anti-vitronectin
antibody, inhibited the TPA-induced cohort migration almost completely. Thus, it
was likely that L-10 cells produced FN themselves and moved on the FN substrate
in an RGD-dependent manner. However, stimulation of migration by type I collagen
coating and inhibition by RGD treatment did not affect the tyrosine
phosphorylation of the E-cadherin-catenin complex induced by TPA, indicating that
cell-cell interactions were adjusted to suit cell migration, irrespective of the
condition of cell-ECM adhesion, during TPA-induced cohort migration.
PMID- 9769129
TI - Cell-type- and tumour-type-related patterns of bcl-2 reactivity in mesenchymal
cells and soft tissue tumours.
AB - Bcl-2 is one of the many proteins that regulate programmed cell death and is
overexpressed in B-cell lymphomas. The expression of bcl-2 in mesenchymal cells
and soft tissue tumours was the subject of this study. Normal mesenchymal tissue
and representative cases of soft tissue tumours of different types (n>200) were
investigated immunohistochemically for bcl-2 expression. Although bcl-2
expression was normally relatively restricted to some smooth muscle cells and
neural cells, bcl-2 immunoreactivity was widespread in different types of soft
tissue neoplasms, both benign and malignant. Consistently positive tumours
included solitary fibrous tumour, haemangiopericytoma, schwannoma and synovial
sarcoma. The few soft tissue tumours that were consistently negative for bcl-2
included nodular fasciitis and desmoid tumour. Leiomyomas and leiomyosarcomas
were heterogeneous; all uterine leiomyomas were bcl-2 positive, but all
oesophageal leiomyomas were negative, paralleling the reactivity observed in the
smooth muscle at those sites. Gastrointestinal stromal tumours showed bcl-2
reactivity; this was less consistent in malignant tumours. Along the malignancy
gradient, there was no consistent trend in the bcl-2 reactivity.
Dermatofibrosarcomas showed increase of bcl-2 expression with fibrosarcomatous
transformation, whereas smooth muscle sarcomas and malignant peripheral nerve
sheath sarcomas were less consistently positive than the corresponding benign
neoplasms. We conclude that bcl-2 expression is widespread in soft tissue
tumours, but shows constitutional expression patterns that are often parallel to
the normal tissue counterparts. Compared with benign soft tissue tumours, bcl-2
expression is often reduced in sarcomas, but it cannot be used as a prognostic
marker without correlation of the data to its phenotypic expression patterns.
PMID- 9769130
TI - Prognostic significance of standardized AgNOR analysis in early and advanced
gastric carcinomas.
AB - To assess the prognostic significance of silver-stained nucleolar organizer
region (AgNOR) proteins, a standardized AgNOR analysis was performed on 78
patients affected by early (EGC, n=24) or advanced (AGC, n=54) gastric
carcinomas. The histopathological diagnosis, grading and staging were done
according to WHO and UICC recommendations; the mean follow-up time was 56.9
months. Visualization and quantification of AgNORs were made in formalin-fixed,
paraffin-embedded sections as specified in the guidelines of the Committee on
AgNOR Quantification (1995). Statistical analysis was performed on the mean AgNOR
area values (NORA). Highly significant differences (P<0.001) were found in NORA
values between EGC and AGC, between low- and high-grade gastric carcinomas and
between patients dead from gastric cancer and living patients. In addition,
significant P values were found on comparison of NORA values relating to pT
status, pN status and stage. Comparison of Kaplan-Meier survival curves revealed
that patients affected by gastric carcinomas with higher NORA values (>5.213
microm2) had a worse prognosis. Finally, using Cox multiple regression analysis,
the AgNOR quantity emerged as a useful independent prognostic variable to predict
the final outcome of patients affected by EGC or AGC.
PMID- 9769131
TI - Identification of mitochondria in liver biopsies. A study by
immunohistochemistry, immunogold and Western blot analysis.
AB - Hepatocytes are rich in mitochondria, which play an important role in hepatic
metabolism. In certain pathologic conditions (most often alcoholic liver disease)
mitochondria became enlarged; nevertheless, even in these conditions they are
hardly detectable on light microscopy. Recently an antimitochondrial antibody
(mAM), which recognizes a 60-kDa protein, has been characterized. The purpose of
the present study was to study immunoreactivity of this antibody in a series of
liver biopsies. We studied 146 liver biopsies using an mAM. In 8 cases an
ultrastructural study was also done, and in 2 cases Western blot analysis was
performed. Cases were divided as follows: alcoholic liver disease (ALD, 31);
steatosis (8); nonalcoholic steatohepatitis (NASH, 1); hepatitis C virus (HCV)
related hepatitis (83); hepatitis B virus (HBV)-related hepatitis (6); primary
biliary cirrhosis (1); sclerosing cholangitis (1); haemosiderosis (1);
sarcoidosis (1); alpha-1-antitrypsin deficiency (1); nonspecific findings (12).
All the patients were investigated for alcohol or drug abuse, pharmacological
treatment, hyperlipidaemia, hypercholesterolaemia and diabetes. Immunoreactivity
was diffuse in cases of ALD, NASH and steatosis, and in patients with drug abuse.
Electron microscopic immunogold and Western blot analysis confirmed that in the
conditions examined the protein recognized by the mAM showed greater expression.
Immunohistochemical staining was helpful in demonstrating a toxic or a metabolic
insult even in cases in which the histological picture was blurred by viral
infection.
PMID- 9769132
TI - Regulation of apoptotic cell death in the pyloric glands of the canine stomach.
AB - In gastrointestinal epithelia, apoptosis has been thought to play a part in the
shedding of postmitotic cells into the lumen. However, we have found that
apoptosis more frequently in the generative cell (G) zone (the lower one third of
the pit) than in the luminal zone (the upper one third of the pit) and the gland
zone in the canine pyloric gland. To analyse the regulation of apoptotic cell
death in each zone, we labelled S-phase cells by single and repeated injections
of bromodeoxyuridine (BrdU) i.v. at intervals of 8 h. We found that 30% of
apoptoses in the G zone were flash-labelled by BrdU and might derive from cells
in or just after the S phase. The incidence of apoptosis and mitotic index did
not change significantly after repeated injections of BrdU until the 49-h point,
when the incidence of apoptosis increased and the mitotic index decreased
significantly in the G zone, while the incidence of apoptosis decreased in the
luminal zone. The BrdU-induced increase of apoptosis and cell-cycle arrest at the
49-h point may be caused by enhanced DNA mispairs that are elicited by
incorporation of BrdU, in particular using the template of BrdU incorporated DNA.
Apoptosis in the luminal zone may be down-regulated by reduced cell production in
the G-zone.
PMID- 9769133
TI - Adenocarcinoma in an ileal pouch after prior proctocolectomy for carcinoma in a
patient with ulcerative pancolitis.
AB - We report the first known case of pouch carcinoma in a 35-year-old female patient
following proctocolectomy for adenocarcinoma in ulcerative pancolitis with
backwash ileitis. Pouch cancer was diagnosed 2 years after the pelvic pouch
procedure, illustrating that there might be a risk of pouch cancer in such
patients. Adenocarcinoma arising in an ileoanal reservoir is rare. Two other
cases have been reported: both patients concerned were believed to have developed
cancer in small areas of residual remaining rectal mucosa.
PMID- 9769134
TI - Are adenomyoepithelioma of the breast and epithelial-myoepithelial carcinoma of
the salivary glands identical tumours?
PMID- 9769135
TI - Trends in infant mortality attributable to birth defects--United States, 1980
1995.
AB - Infant mortality has declined in the United States because of advances in public
health and clinical medicine. Birth defects are the leading cause of infant
mortality, but infant mortality attributable to birth defects (IMBD) has not
declined as rapidly as overall infant mortality. From 1968 to 1995, the
proportion of IMBD increased from 14.5% to 22.2%. To help focus efforts to reduce
IMBD, CDC examined trends in IMBD, highlighting demographic, geographic, and
defect-specific mortality rates. This report summarizes the results of this
analysis, which indicate variation in rates for IMBD by sex, race/ethnicity, and
state of residence.
PMID- 9769136
TI - Progress toward poliomyelitis eradication--India, 1998.
AB - In 1988, the World Health Assembly resolved to eradicate poliomyelitis globally
by 2000. In 1995, India began to accelerate implementation of polio eradication
strategies by conducting annual National Immunization Days (NIDs). In 1997, an
active surveillance system for polio using acute flaccid paralysis (AFP) as a
screening case definition was established. This report summarizes progress toward
polio eradication, focusing on the implementation of supplemental vaccination
activities and the establishment of sensitive surveillance. The findings suggest
that NIDs in India have decreased previously widespread poliovirus circulation.
PMID- 9769137
TI - Incidence of foodborne illnesses--FoodNet, 1997.
AB - Each year, millions of persons become ill from foodborne diseases, though many
cases are not reported. The Foodborne Diseases Active Surveillance Network (Food
Net), the primary foodborne diseases component of CDC's Emerging Infections
Program, was developed to better characterize, understand, and respond to
foodborne illnesses in the United States. This report describes FoodNet
surveillance data from 1997, the second year of surveillance, and compares
findings with data from 1996. The findings demonstrate regional and seasonal
differences in the reported incidence of certain bacterial and parasitic diseases
and that substantial changes occurred in the incidence of illnesses caused by
some pathogens (e.g., Vibrio and Escherichia coli O157:H7) but the overall
incidence of illness caused by the seven diseases under surveillance in both
years changed little.
PMID- 9769138
TI - Lymphoid cell-growth hormone interactions: a serum-free model.
PMID- 9769139
TI - Crystallization of neutral red vital stain from minimum essential medium due to
pH instability.
PMID- 9769140
TI - Strain-induced dual alignment of L6 rat skeletal muscle cells.
PMID- 9769141
TI - Characterization of NR10(2) macrophages.
PMID- 9769142
TI - Matrix mRNA levels in ligament tissue versus cells.
PMID- 9769143
TI - Polyamine as a growth promoter for cultured insect cells.
PMID- 9769144
TI - Primary culture of colonocytes in rotating bioreactor.
PMID- 9769145
TI - The motile behavior of human breast cancer cells characterized by time-lapse
videomicroscopy.
PMID- 9769146
TI - Culture of mosquito cells in Eagle's medium.
PMID- 9769147
TI - Acute cytotoxicity testing with cultured human lung and dermal cells.
AB - An extensive in vitro study with cultured cells was conducted to test the basal
cytotoxicity theory. This theory suggests that most chemical injury, at least in
vitro, is a manifestation of one or more insults to the basic cellular structures
and functions common to mammalian cells. This accounts for the similarity of
results in multilaboratory studies. Human fetal lung fibroblasts (HFL1), and
human skin fibroblasts (WS1, Detroit551) were studied in culture to evaluate
their potential to screen for cytotoxicity. Confluent monolayers were incubated
in the absence or presence of increasing concentrations of test chemicals for 24
h, and the MTT assay was used to assess toxicity. Inhibitory concentrations were
extrapolated from concentration-effect curves after linear regression analysis.
Twenty-nine chemicals were tested with each cell line and the cytotoxicity data
compared to rodent and human lethal concentrations. The data suggest that the
experimental IC50 values are as accurate predictors of human toxicity as
equivalent toxic blood concentrations derived from rodent LD50s. In addition,
lung and skin fibroblasts revealed no significant differences among the three
cell lines. The results support the conclusion that finite cell lines of human
origin have the potential for screening chemicals for human toxicity. In
combination with previously published reports, the data suggest that a basal
cytotoxic phenomenon may explain the similarity of results among different human
cell lines.
PMID- 9769148
TI - Organotypic culture of human ovarian surface epithelial cells: a potential model
for ovarian carcinogenesis.
AB - The objective of this work was to establish an in vitro multidimensional culture
system for human ovarian surface epithelial (HOSE) cells as a model for ovarian
carcinogenesis. The epithelial origin of cell outgrowth from cells obtained from
the ovarian surface was confirmed by keratin staining. Two cultures from two
different patients were established, HOSE-A and HOSE-B. Cultures were infected
with a retrovirus expressing human papillomavirus genes E6 and E7 to extend their
life span. HOSE cells were seeded onto collagen gels containing NIH3T3-J2
fibroblasts as feeder cells and grown to confluence submerged in growth medium.
The collagen bed was then raised to the air-medium interface for 7 d (organotypic
culture). Microscopically, fixed cultures revealed a single layer of flat cells
growing on the collagen surface, reminiscent of HOSE cells in vivo. Infected HOSE
A and HOSE-B cells exhibited aberrant growth because they stratified. In
addition, established ovarian cancer lines grown in this fashion stratified and
showed malignant phenotypes. Thus, cells grown in organotypic culture resemble
their in vivo counterparts, providing a basis for establishing a system to study
growth, proliferation, differential gene expression, and perhaps malignant
transformation of HOSE cells.
PMID- 9769149
TI - Fibroblast movements during contraction of collagen lattices--a quantitative
study using a new three-dimensional time-lapse technique with phase-contrast
laser scanning microscopy.
AB - In this study we assessed the behavior of fibroblasts during contraction of
collagen lattices. We applied a new technique for three-dimensional time-lapse
studies of movements of living cells using phase-contrast laser scanning
microscopy. Five anchored and five floating collagen lattices were studied
regarding the activity of cells during a 7-h period of active contraction. Three
dimensional reconstructions of the fibroblasts and their extensions were made
from datasets of 16-26 "optical sections" 5 microm apart recorded hourly during
the period of measurements. The distance between fibroblast nuclei in the
floating lattices decreased by a mean of 6.8 microm, but remained constant in the
anchored group. Only minor variations were found in the angle between a line
connecting any two nuclei and the tangent of the lattice margin. The lengths of
the cellular extensions continuously changed by shortening and extending, and an
increasing number of intercellular contacts were established with time. The angle
between the extensions and the periphery of the lattice varied continually, and
no distinct pattern of arrangement of the extensions was seen. In conclusion, we
have shown in living cells in vitro that fibroblasts do not appear to move around
within lattices during contraction but rather send out and withdraw cellular
extensions continuously. This speaks against cellular locomotion or movement as a
main feature of contraction. Time-lapse scanning laser microscopy has also been
shown to be a suitable method to study cellular behavior quantitatively in three
dimensions during lattice contraction.
PMID- 9769150
TI - In vitro biosynthesis of juvenile hormone in larval honey bees: comparison of six
media.
AB - We have formulated a tissue culture medium based on the components of larval
honey bee hemolymph. Using an in vitro radiochemical assay to measure juvenile
hormone biosynthesis, we compared our larval-based medium to four commercially
available media (Grace's, Medium-199; Shields and Sang M3, and Minimum Essential
Medium), and a medium based on adult honey bee hemolymph. All media were
formulated without methionine. There was no significant difference in the amounts
of juvenile hormone produced by the larval medium and Grace's; both of these
media, however, were more suitable than the remaining four. Our larval-based
tissue culture medium should prove useful in studies aimed at elucidating the
underlying hormonal mechanism(s) of caste development in honey bees.
PMID- 9769151
TI - BG-1 ovarian cell line: an alternative model for examining estrogen-dependent
growth in vitro.
AB - Examination of estrogen-responsive processes in cell culture is used to
investigate hormonal influence on cancer cell growth and gene expression. Most
experimental studies have used breast cancer cell lines, in particular MCF7
cells, to investigate estrogen responsiveness. In this study we examined an
ovarian cancer cell line, BG-1, which is highly estrogen-responsive in vitro.
This observation, plus the fact that the cells are of ovarian rather than mammary
gland origin, makes it an attractive alternative model. 17Beta-estradiol,
epidermal growth factor, and insulin-like growth factorinduced proliferation of
BG-1 and MCF7 cells. Viability was dependent on these growth factors in BG-1
cells, but not in MCF7 cells. Therefore, we examined the differences between
these two cell lines with respect to estrogen and growth factor receptors. BG-1
cells have twice as many estrogen receptors as MCF7 cells, and BG-1 cells have
higher insulin-like growth factor-1 and epidermal growth factor receptor levels
than MCF7 cells. This may also explain why BG-1 cells proliferate 56% more
robustly in serum and show more serum dependence in culture. In both BG-1 and
MCF7 cells, epidermal growth factor receptor number is low (<20000/cell), while
insulin-like growth factor-1 receptor level was highest in estrogen receptor
positive cell lines. For example, insulin-like growth factor-1 receptor was
higher in BG-1 and MCF7 cells than in estrogen receptor negative cells (HeLa >
MDA-MB-435 > HBL100). In conclusion, BG-1 cells are an excellent model for
understanding hormone responsiveness in ovarian tissue and an alternative for
examining estrogen receptor-mediated and insulin-like growth factor-1/epidermal
growth factor/estrogen cross-talk processes because of their sensitivity to these
factors.
PMID- 9769152
TI - Response of preimplantation murine embryos to heat shock as modified by
developmental stage and glutathione status.
AB - Objectives were to characterize developmental changes in response to heat shock
in the preimplantation mouse embryo and to evaluate whether ability to synthesize
glutathione is important for thermal resistance in mouse embryos. Heat shock (41
degrees C for 1 or 2 h) was most effective at disrupting development to the
blastocyst stage when applied to embryos at the 2-cell stage that were delayed in
development. Effects of heat shock on ability of embryos to undergo hatching were
similar for 2-cell, 4-cell, and morula stage embryos. The phenomenon of induced
thermotolerance, for which exposure to a mild heat shock increases resistance to
a more severe heat shock, depended upon stage of development and whether embryos
developed in vitro or in vivo. In particular, induced thermotolerance was
observed for morulae derived from development in vivo but not for 2-cell embryos
or morulae that developed in culture. Administration of buthionine sulfoximine to
inhibit glutathione synthesis did not increase thermal sensitivity of 2-cell
embryos or morulae but did reduce subsequent development of 2-cell embryos at
both 37 degrees and 41 degrees C. In summary, changes in the ability of 2-cell
through morula stages to continue to develop following a single heat shock were
generally minimal. However, 2-cell embryos delayed in development had reduced
thermal resistance, and therefore, maternal heat stress may be more likely to
cause mortality of embryos that are already compromised in development. There
were also developmental changes in the capacity of embryos to undergo induced
thermotolerance. Glutathione synthesis was important for development of embryos
but inhibition of glutathione synthesis did not make embryos more susceptible to
heat shock.
PMID- 9769153
TI - Factors affecting Caco-2 intestinal epithelial cell interleukin-6 secretion.
AB - Intestinal epithelial cells (IEC) have previously been shown to produce several
cytokines including interleukin-6 (IL-6). However, many factors which may
regulate IL-6 secretion by human IEC still remain a mystery due in part to the
lack of appropriate model cell lines and the difficulty of culturing human IEC
over long periods of time. We have determined that the human colonic carcinoma
cell line Caco-2 is capable of secreting IL-6 when stimulated by the inflammatory
cytokines IL-1beta or tumor necrosis factor-alpha (TNF-alpha), and stimulation of
these cells with IL-1beta plus TNF-alpha induced a synergistic enhancement of IL
6 secretion. The inflammatory cytokine-induced enhancement in IL-6 secretion was
greatest when the cells were cultured in a 10% CO2 atmosphere as compared to
cells grown in 5% CO2, suggesting that environmental CO2 levels may affect IEC
cytokine secretion. Finally, long-term culture of the Caco-2 cells to induce
cellular differentiation had no effect on the capacity of these cells to produce
IL-6, indicating that the regulation of IL-6 secretion was not affected by
differentiation. Taken together, these studies provide important information on
the factors which regulate IL-6 secretion by human IEC as they may contribute to
the cytokine network during a mucosal inflammation. The results also suggest that
the Caco-2 cell line is an appropriate model for further studies on the
regulation of cytokine secretion by human IEC.
PMID- 9769154
TI - Immunoreactivity of neural crest-derived cells in thymic tissue developing under
the rat kidney capsule.
AB - In order to study the functional development of a thymus in an experimental
model, small pieces of adult rat thymic tissue were cultured for 9 days and
implanted under the kidney capsule of littermates. The tissues were examined with
a panel of antibodies raised against thymic and neural factors and neural crest
cells at intervals from 5 to 13 days. At 5 days post-implantation, there were
groups of L1+ cells within the implants that reacted with antibodies raised
against neural and neural crest cell markers. L1+ cells were highly mitotic,
rounded cells measuring 8.7 +/- 0.6 micrometer in diameter. Double immunostaining
with different combinations of antibodies showed that 94% of the L1+ cells were
also TH+, and many were HNK-1/NCAM+, PGP 9.5+, NGF+, chromogranin A+, VIP+,
S100+, CGRP+, GAD+, and A2B5+. A few were also pan-cytokeratin+. These results
indicate that these cells are derived from neural crest derived cells and belong
to the neuroepithelial line of development. The L1+ cells were most numerous
before nerves appeared (about Day 9) and reduced in number and extent as the
thymus differentiated. The neural crest cells occasionally had long cytoplasmic
extensions, but it was not possible to decide if they formed the nerves that
appeared in the implants. Adult thymuses also contained a population of L1+ and
HNK-1/NCAM+ cells, mainly in the subcapsular cortex, the septa, and the medulla.
These cells could be a source of neural crest cells able to repopulate the
implant. The adult thymus may always contain a reservoir of cells potentially
capable of producing neuropeptides and transmitter factors required for thymic
growth and regeneration.
PMID- 9769155
TI - Sympathectomy-induced immune changes are not abrogated by the glucocorticoid
receptor blocker RU-486.
AB - Removal of sympathetic noradrenergic input to the immune system by injection of 6
hydroxydopamine (6-OHDA) triggers increases in antigen-specific in vitro
splenocyte proliferation and cytokine production in BALB/cJ and C57B1/6J mice.
This examines the possible role of glucocorticoids in these previously reported
changes. In both strains, chemical sympathectomy triggers an elevation of
glucocorticoid levels immediately following injection of 6-OHDA, returning to
normal within one to two days. In the BALB/cJ strain, glucocorticoid elevation is
seen only after the initial 6-OHDA injection; levels in chronically denervated
animals are not different from controls. In the C57B1/6J strain, the increase is
seen even with chronically denervated animals. Prior implantation of mice with
pellets containing the glucocorticoid receptor antagonist RU-486 does not
abrogate denervation-induced increases in cytokine production or proliferation in
either strain. In addition to the previously reported increased interleukin (IL)
2 and IL-4 production, there is an increase in IFN-gamma production in the
C57B1/6J strain following either acute or chronic denervation. The persistence of
denervation-induced changes even when the effect of corticosterone is blocked
with RU-486 or diminished with chronic denervation indicates that the changes are
driven mainly by a glucocorticoid-independent mechanism.
PMID- 9769156
TI - IL-6 knock-out mice show modified basal immune functions, but normal immune
responses to stress.
AB - To better determine the role of interleukin-6 in the mechanisms that regulate
stress-induced immunosuppression, we used in this study an interleukin-6
deficient mice model recently generated by gene targeting. We report here that,
in basal conditions, mutant mice are characterized by altered immune functions.
Natural killer activity and interleukin-2 production are lower in splenocytes of
interleukin-6 deficient mice compared to those of controls, whereas Concanavalin
A-induced splenocyte proliferation is comparable with that observed in wild-type
mice. Moreover, splenocyte concentrations of the immunosuppressive opioid peptide
beta-endorphin are higher in interleukin-6 deficient mice while serum
corticosterone concentrations are unchanged. After exposure to 16 h of restraint
stress, a significant suppression of the immune parameters is exhibited and a
significant increase of splenocyte beta-endorphin concentrations are present in
knock-out and normal animals. Finally, corticosterone is normally induced in
stressed interleukin-6-deficient mice, thus demonstrating that interleukin-6 is
not crucial for the activation of the hypothalamic-pituitary-adrenal axis. In
conclusion, our results indicate that interleukin-6 is not a key factor in the
immunosuppression observed after restraint stress.
PMID- 9769157
TI - Selective effects of peripheral lipopolysaccharide administration on contextual
and auditory-cue fear conditioning.
AB - The reported experiments explore the effects of peripheral LPS administration on
learning and memory processes. As measured by the conditioned freezing response,
intraperitoneal LPS administration given after conditioning impaired contextual
but not auditory-cue fear conditioning in both juvenile (hooded Long Evans) and
adult rats (albino Sprague Dawley) of two different strains. This impairment in
contextual fear conditioning was not dependent on the presence of the tone.
Preexposure to the context eliminated the effect of LPS on contextual fear
conditioning, and in addition, LPS given after context preexposure negated the
beneficial effects of preexposure on contextual fear. These results suggest that
LPS disrupts posttrial memory consolidation processes. In support of the
hypothesis that LPS-induced proinflammatory cytokine release is involved in
producing the impairment in contextual fear caused by LPS, peripheral interleukin
1 receptor antagonist (IL-1ra) administered subcutaneously at a dose of 100 mg/kg
prevented the impairment in contextual fear caused by LPS. These experiments
provide evidence for a role of immune activation and cytokine activity in
learning and memory processes.
PMID- 9769158
TI - Central nervous system activation following peripheral chemical sympathectomy:
implications for neural-immune interactions.
AB - Many studies have demonstrated that ablation of the sympathetic nervous system
(SNS) alters subsequent immune responses. Researchers have presumed that the
altered immune responses are predominantly the result of the peripheral
phenomenon of denervation. We, however, hypothesized that chemical sympathectomy
will signal and activate the central nervous system (CNS). Activation of the CNS
was determined by immunocytochemical visualization of Fos protein in brains from
male C57BL/6 mice at 8, 24, and 48 h following denervation. A dramatic induction
of Fos protein was found in the paraventricular nucleus (PVN) of the hypothalamus
and other specific brain regions at 8 and 24 h compared to vehicle control mice.
Dual-antigen labeling demonstrates that corticotrophin releasing factor (CRF)
containing neurons in the PVN are activated by chemical sympathectomy; however,
neurons containing neurotransmitters which may modulate CRF neurons, such as
vasopressin, tyrosine hydroxylase, and adrenocorticotropin, do not coexpress Fos.
Our findings suggest an involvement of the CNS in sympathectomy-induced
alterations of immunity.
PMID- 9769159
TI - Human brain-immune relationships: a PET study.
AB - To study brain-immune relations, we correlated positron emission tomographic
(PET) measures of regional cerebral blood flow (rCBF) with immune measures in 10
female volunteers. The natural killer (NK) activity correlated negatively with
activity bilaterally in the secondary sensory cortex, whereas the Concanavalin A
(Con A) response correlated positively with rCBF bilaterally in secondary visual,
motor, and sensory cortices, the thalamus, the putamen, and the left hippocampus.
Although representing preliminary data from a small number of subjects, these
observations provide further support for the presence of interactions between the
brain and the immune system.
PMID- 9769160
TI - Effects of cell concentration on viability and metabolic activity during
cryopreservation.
AB - Increasing the cell concentration during the cryopreservation of red blood cells
(RBC) increased hemolysis. Similarly, increasing the cell concentration during
the cryopreservation of hepatocytes reduced both the viability of the cells as
assessed by trypan blue exclusion and the metabolic activity of the trypan blue
excluding cells. In both cell types, significant damage appeared at cell
concentration levels exceeding 60%. With tightly packed RBC, hemolysis reached
63%, while for hepatocytes after thawing and dilution, trypan blue viability was
reduced to 41% of that of the cells initially isolated. The viability of
cryopreserved hepatocytes, estimated by trypan blue exclusion, was considerably
reduced following incubation for 1 h at 37 degrees C and the extent of this
reduction was also a function of cell concentration during freezing and thawing.
The trypan blue viability of hepatocytes that were tightly packed during
cryopreservation and then incubated at a concentration of 5 x 10(6) viable
cells/ml fell dramatically to only 12.5%. The protein-synthesizing activity and
the membrane transport activity of these cells, expressed in terms of cells that
excluded trypan blue immediately following thawing and removal of the
cryoprotectant, were reduced to 38.7 and 33.5%, respectively, of the activity in
cells that were packed at 10% cell concentration. The fall in metabolic activity
may have been due to complete loss of activity in some of the cells or reduced
activity in most or all of the cells or any combination of these factors. It is
concluded that there may be many mechanisms involved, but the most important
factor is probably stresses produced by unphysiological cell-cell contacts
occurring during the freeze-thaw cycle.
PMID- 9769161
TI - Cryopreservation of pancreatic islets prior to transplantation: a comparison
between UW solution and RPMI culture medium.
AB - Effective cryopreservation of pancreatic islets would be valuable in several
contexts: for the assessment of islet cell viability, the measurement of beta
cell function, and the maintenance of viability and sterility prior to islet
transplantation. In this study, isolated rat islets were cryopreserved or not
following overnight culture and the most suitable preservation solution for
transportation between centers was sought. Unfrozen and frozen-and-thawed islets
were allocated to each of four different groups: untreated controls; cultured
overnight in RPMI at 37 degrees C; cold stored at 4 degrees C in RPMI for 18-24
h; and stored at 4 degrees C in University of Wisconsin (UW) solution for 18-24
h. The greatest cell viability, as assessed by ethidium bromide/acridine orange
staining and image analysis, was observed when postthawed islets were cultured in
RPMI, whereas the least viable samples were those that were stored in UW
solution. Measurement of insulin content and secretion in static incubation
assays using 2.8 and 16.7 mM glucose showed that all treated groups exhibited a
significant insulin secretory response to glucose stimulation whereas the
untreated frozen-thawed islets failed to show any response. The cryopreserved
islets in each group were equally successful in reversing hyperglycemia in
streptozotocin-treated allogeneic rats when grafted intraportally in sufficient
numbers (2000-2500). The groups also showed a similar mean graft survival time of
6-7 days before rejection. However, the best experimental group (the postthaw
cultured islets) failed to cure diabetic rats when grafted in a smaller numbers
(<2000). These data demonstrate prompt and sustained function in cryopreserved
islets when they were maintained by any of the methods studied if they were
grafted in sufficient numbers. We conclude that cold storage of thawed
cryopreserved islets using either RPMI or UW solution is an effective method for
their transportation and/or storage, but does not reduce their immunogenicity
before transplantation.
PMID- 9769162
TI - Crystallization of ice in aqueous solutions of glycerol and dimethyl sulfoxide 2:
ice crystal growth kinetics.
AB - The crystallization of ice in aqueous solutions of glycerol and dimethyl
sulfoxide (Me2SO) has been studied using a combined DSC-video microscope
technique. The solutions investigated were 50w/w% glycerol and 45w/w% Me2SO; both
of these solutions have a solute concentration of approximately 16 mol%. The
rates of growth of the external surfaces of ice crystals from both of these
solutions were determined over broad temperature ranges. The growth rates were
found to be generally independent of time, particularly at lower temperatures.
The ice crystal growth rate in the glycerol solution became negligible at a
significantly higher temperature than in the Me2SO solution. Addition of anti
freeze protein from the winter flounder at concentrations of 1.7 and 9.9 mg g-1
was found to have no significant effect on the ice crystal growth rates in 50w/w%
glycerol solutions.
PMID- 9769163
TI - Trehalose-mediated protection of the plasma membrane H+-ATPase from Kluyveromyces
lactis during freeze-drying and rehydration.
AB - During freeze-drying and rehydration, the activity of the H+-ATPase from the
plasma membrane of Kluyveromyces lactis was preserved by increasing
concentrations of carbohydrates. When the H+-ATPase was freeze-dried in the
absence of carbohydrates the activity was lost. The protective efficiency of
carbohydrates was as follows: trehalose > maltose > sucrose > glucose >
galactose. Each carbohydrate exhibited the maximal protection at a concentration
of 20 mg carbohydrate per milligram of protein or above. No structural changes of
the rehydrated H+-ATPase were detected by intrinsic fluorescence measurements.
Trehalose, at 20 mg/mg protein, protected the enzyme activity completely during
freeze-drying and rehydration. Rehydration temperature was critical; at 20
degrees C or below, activity was fully retained, while at 30, 40, or 50 degrees C
activity decreased in proportion with temperature. The trehalose-protected freeze
dried H+-ATPase was stored at different temperatures for up to 60 days. Storage
at 4 degrees C resulted in retention of most of the enzymatic activity, while
storage at 20 or 30 degrees C resulted in loss of activity. The protection of the
H+-ATPase by trehalose suggests that this carbohydrate might protect other
membrane enzymes from inactivation during handling.
PMID- 9769164
TI - Production of monozygotic twins after freezing and thawing of bisected mouse
embryos.
AB - We examined the viability of mouse bisected embryos after freezing and thawing
and produced monozygotic twin mice from these embryos. Two-cell embryos were
collected from superovulated mature agouti, F1 hybrid (C57BL/6 x CBA) female
mice. For bisection, one blastomere of the embryo was aspirated with a
micropipette and injected into an empty zona pellucida. After culture for 24 to
28 h to the compacted 4- to 8-cell stage or 48 to 52 h to the late morula to
blastocyst stage, the embryos were slowly frozen (-0.5 to -1.0 degrees C/min),
thawed (30 degrees C/min), cultured for 24 h, and then transferred to recipient
females. The bisected embryos without zonae pellucidae had developmental ability
in vitro similar to those with zonae pellucidae (88% vs 89%). However, after
freezing and thawing at the compacted 4- to 8-cell stage, bisected embryos with
zonae pellucidae had higher viability than those without (60% vs 15%). Zona
enclosed, bisected embryos frozen at the compacted 4- to 8-cell stage were more
resistnat to freezing and thawing than those at the late morula to blastocyte
stage (60% vs 23%). After transfer to recipients 26% of the zona enclosed
bisected embryos frozen-thawed at the 4- to 8-cell stage developed to living
fetuses a day 17.5 to 18.0 of pregnancy, which was slightly but not significantly
lower than that of fresh bisected embryos (48%). On the other hand, only 5% of
bisected embryos frozen-thawed at the late morula to blastocyst stage developed
to young. The transfer of 15 sets of twin blastocysts as pairs that had been
frozen and thawed at the compacted 4- to 8-cell stage yielded 2 (13%) sets of
monozygotic twins.
PMID- 9769165
TI - Hibernation induces expression of moesin in intestinal epithelial cells.
AB - Identification of proteins that are differentially expressed in mammals that
hibernate can provide insight into mechanisms that preserve cellular function at
low temperatures. A candidate protein was identified in intestinal brush border
membranes of 13-lined ground squirrels. Intestinal brush border membrane proteins
were separated using SDS-PAGE and gels were stained with Coomassie blue. We
observed a approximately 75-kDa band that was specifically increased in brush
border membranes isolated from torpid squirrels compared with summer active
squirrels. The 75-kDa band was cut from one-dimensional gels and sequenced. A 17
amino acid sequence was identified of which amino acids 2-17 matched exactly a
portion of moesin, a membrane-cytoskeletal linking protein and member of the ERM
(ezrin/radixin/moesin) family. The sequence results were confirmed using anti
moesin antibodies that detected strong bands at approximately 75 kDa on Western
blots of brush border membranes in torpid squirrels (Tb approximately 7 degreesC)
and only faint signals in summer squirrels (Tb approximately 37 degrees C) or
aroused hibernators (Tb approximately 37 degrees C). In contrast, signals
obtained using anti-ezrin antibodies were uniformly strong in all squirrels,
regardless of activity state. Intestinal brush borders of mice and rats expressed
ezrin but not moesin. These results provide evidence for the physiological
induction of an ERM protein in intestinal epithelial cells of torpid hibernators
and support the idea that hibernation involves differential expression of gene
products that may facilitate viability of cells at low temperatures.
PMID- 9769166
TI - Cryopreservation of spermatozoa from freeze-tolerant and -intolerant anurans.
AB - Spermatozoa of the freeze-tolerant wood frog (Rana sylvatica) were used to
develop a general protocol for the frozen storage of amphibian spermatozoa.
Tolerance of spermatozoa to cryoprotective agents and freezing in suspension (-80
degrees C) was determined from rates of sperm lysis and dual-fluorochrome vital
dye assays. We tested the efficacy of four cryoprotectants (Me2SO, methanol,
glycerol, and ethylene glycol), two supplements (fetal bovine serum or
glutathione), and combinations of these cryoprotectants and supplements. Me2SO
and fetal bovine serum were the most effective cryoprotectant and supplement,
respectively, in reducing sperm lysis. Vital dye assays showed that viability was
greatest for spermatozoa treated with both Me2SO and fetal bovine serum. Thus,
this combination was used to cryopreserve spermatozoa from the freeze-intolerant
anurans, Rana pipiens and Bufo americanus. Recovery of viable spermatozoa was
significantly greater for R. sylvatica (mean +/- SE = 81.2 +/- 9.6%) than for R.
pipiens (59.0 +/- 2.8%) and B. americanus (47.8 +/- 4.1%), perhaps owing to
inherent factors promoting its freeze tolerance. Nonetheless, our results support
the feasibility of using gamete cryopreservation techniques in programs aimed at
the captive propagation of amphibians.
PMID- 9769167
TI - Respiratory responses to chilling and freezing in two sub-antarctic insects.
AB - The effects of chilling (to temperatures above the supercooling point, SCP) and
freezing on respiration of adults and larvae of two coleopterans living on sub
Antarctic South Georgia (54 degrees S, 37 degrees W), Hydromedion sparsutum and
Perimylops antarcticus (Coleoptera, Perimylopidae), were quantified. Respiration
rates of individual insects (live weights, 11-21 mg) were measured at 10 degrees
C prior to chilling (-4 degrees C) or freezing (SCP range -3.8 to -5.3 degrees C)
and posttreatment. The species possess a small amount of freeze tolerance in both
adults and larvae. Chilling had no significant effects on respiration rates of P.
antarcticus and H. sparsutum, although mean levels were depressed by 6-15%.
Freezing produced considerable enhancement of respiratory activity. Mean values
increased postfreezing in larvae (+34%) of H. sparsutum and in both larvae (+44%)
(P < 0.01) and adults (77%) (P < 0.05) of P. antarcticus. Chilling and freezing
had different effects on respiration rates and P. antarcticus showed the greatest
metabolic response to freezing.
PMID- 9769168
TI - Muscle minus myoD.
PMID- 9769169
TI - A role for nautilus in the differentiation of muscle precursors.
AB - In the Drosophila embryo, nautilus is expressed in a subset of muscle precursors
and differentiated fibers and is capable of inducing muscle-specific
transcription, as well as myogenic transformation. In this study, we examine the
consequences of nautilus loss-of-function on the development of the somatic
musculature. Genetic and molecular characterization of two overlapping
deficiencies, Df(3R)nau-9 and Df(3R)nau-11a4, revealed that both of these
deficiencies remove the nautilus gene without affecting a common lethal
complementation group. Individuals transheterozygous for these deficiencies
survive to adulthood, indicating that nautilus is not an essential gene. These
embryos are, however, missing a subset of muscle fibers, providing evidence that
(1) some muscle loss can be tolerated throughout larval development and (2)
nautilus does play a role in muscle development. Examination of muscle precursors
in these embryos revealed that nautilus is not required for the formation of
muscle precursors, but rather plays a role in their differentiation into mature
muscle fibers. Thus, we suggest that nautilus functions in a subset of muscle
precursors to implement their specific differentiation programs.
PMID- 9769170
TI - Somitogenesis controlled by Noggin.
AB - In vertebrates, the segmented somites, which are the medial-most component in the
paraxial mesoderm, are the entity giving rise to the axial bones and skeletal
muscles. We previously demonstrated that the mechanism that distinguishes the
somite from the more lateral mesoderm (lateral plate) involves different levels
of BMP-4 activity which is highest in the lateral plate. We report that Noggin,
an antagonist of BMP-4, is expressed in the presumptive somite and appears to
control effective levels of BMP-4 to differentiate somitic mesoderm from the
lateral plate. When Noggin-producing cells were implanted into the presumptive
lateral plate, they produced ectopic somites that were respecified from the
lateral plate precursors. These somites exhibited no mediolateral (M-L) polarity,
but acquired it when implanted Noggin was eliminated. Thus, in normal
embryogenesis no or low BMP-4 activity realized by Noggin specifies the somites
in the medial-most portion of the paraxial mesoderm, and then BMP-4 emanating
from the lateral plate subsequently establishes the M-L polarity in the somites.
PMID- 9769171
TI - FREAC-1 contains a cell-type-specific transcriptional activation domain and is
expressed in epithelial-mesenchymal interfaces.
AB - The forkhead transcription factor FREAC-1 is a potent transcriptional activator.
We have localized a transcriptional activation domain in the C-terminus of FREAC
1 and another one to a stretch of approximately 60 amino acids in the central
part of the protein. While the C-terminal activation domain activates in all cell
lines tested, the activation domain in the central part of the protein is
functional only in cell lines derived from lung. This cell-type-specific activity
is retained when the activation domain is fused to the heterologous DNA binding
domain of Gal4. The human FREAC-1 gene was found to consist of two exons
separated by an intron of 1.2 kb. Exon 1 encodes the forkhead DNA binding domain
and the cell-type-specific activation domain. Exon 2 encodes the general
activation domain. The distribution of FREAC-1 expression during embryogenesis
was investigated by in situ hybridization. FREAC-1 mRNA was found in mesenchyme
in immediate proximity to endodermal epithelia throughout the digestive, urinary,
and respiratory tracts. Mesenchyme surrounding the notochord and adjacent to the
ectodermal epithelia of the oral cavity and developing teeth also expresses FREAC
1. The pattern of FREAC-1 expression, with highest levels in the mesenchyme next
to the epithelium and gradually diminishing as the distance from the epithelium
increases, suggests that FREAC-1 expression is a response to epithelial paracrine
signaling and that FREAC-1 may play a role in epitheliomesenchymal interactions.
PMID- 9769172
TI - Normal reproductive and macrophage function in Pem homeobox gene-deficient mice.
AB - Interaction between germ cells and the supporting somatic cells guides many of
the differentiative processes of gametogenesis. The expression pattern of the Pem
homeobox gene suggests that it may mediate specific inductive events in murine
reproductive tissues. During gestation, Pem is expressed in migrating and early
postmigratory primordial germ cells, as well as in all embryo-derived
extraembryonic membranes. Pem expression ceases in the germline after Embryonic
Day 14 in both sexes and then reappears postnatally in the supporting cells of
the gonad. In mature mice, Pem is produced by testicular Sertoli cells during
stages VI-VIII of spermatogenesis and transiently by ovarian granulosa cells
lining periovulatory follicles. Despite this tightly regulated reproductive
expression pattern, mice with a targeted mutation in Pem have normal fecundity,
with no detectable alteration in extraembryonic testicular or ovarian development
or function. We also show that Pem is expressed throughout embryonic and adult
development in a subset of a tissue-specific class of macrophages, Kupffer cells,
as well as in a localized fraction of cells in macrophage cell lines. Although
the number of Pem-positive Kupffer cells increases in mice treated with
lipopolysaccharide, loss of Pem does not detectably interfere with the cells'
ability to induce iNOS expression, demonstrating this Kupffer cell function does
not require Pem. No differences were observed between Pem-knockout mice in 129,
C57BL6/J, or mixed genetic backgrounds. Together, these data show that Pem is
dispensable for embryonic and postnatal development, gonadal function, and
Kupffer cell activation, perhaps due to compensatory expression of a similar
homeobox gene.
PMID- 9769173
TI - Analysis of epithelial-mesenchymal interactions in the initial morphogenesis of
the mammalian tooth.
AB - Epithelial-mesenchymal interactions govern the development of epidermal organs
such as teeth. During the early stages of tooth development, a local ectodermal
thickening which expresses several signaling molecules appears. It is believed
that these in turn signal to the underlying mesenchyme triggering mesenchymal
condensation and tooth development. For example, epithelially expressed Bmp4
induces Msx1 and Lef1 as well as itself in the underlying mesenchyme. In this
paper we have investigated the role of four epithelial signaling molecules, Bmp2,
Shh, Wnt10a, and Wnt10b, in the early inductive cascades that govern tooth
development. We show that all four genes are specifically expressed in the
epithelium between E11.0 and E12.0 when tooth morphogenesis is first apparent.
Although Shh, Bmp2, and Wnt10b have similar, if not identical, expression
patterns, each signal has a distinct molecular action on the jaw mesenchyme.
Whereas Shh and Wnt10b can induce general Hedgehog and Wnt targets, Ptc and Gli
for Shh and Lef1 for Wnt10b, only Bmp2 is able to induce tooth-specific
expression of Msx1. Thus, there are distinct targets for all three pathways.
Interestingly, both Bmp and Wnt signaling activate Lef1, making it a candidate
for integrating the two distinct signaling pathways.
PMID- 9769174
TI - The classical mouse mutant postaxial hemimelia results from a mutation in the Wnt
7a gene.
AB - The study of spontaneous mutations has aided the understanding of developmental
processes. A large collection of spontaneous or "classical" mouse mutations has
been accumulated over many decades. One of the mutations causes the postaxial
hemimelia (px) phenotype, which consists of limb patterning defects accompanied
by Mullerian duct-associated sterility in both sexes. We were intrigued that both
the limb and the Mullerian duct px phenotypes are similar to those caused by
mutations in the gene encoding the Wnt 7a signaling molecule. In this paper, we
investigate the nature of the px mutation. Morphological analysis and breeding
experiments demonstrate that the px phenotype indeed results from a mutation in
the Wnt 7a gene. Molecular analysis demonstrates that px results from a 515-bp
deletion in the Wnt 7a gene. This generates an abnormal splicing event, which
ultimately produces a truncated Wnt 7a protein of half the normal size. Thus, the
px mutation is predicted to be a likely null allele of the Wnt 7a gene. Our
results provide another interesting example of a classical mutation that disrupts
an important patterning gene in development.
PMID- 9769175
TI - Chondroitin sulfates modulate axon guidance in embryonic Xenopus brain.
AB - Chondroitin sulfate proteoglycans display both inhibitory and stimulatory effects
on cell adhesion and neurite outgrowth in vitro. The functional activity of these
proteoglycans appears to be context specific and dependent on the presence of
different chondroitin sulfate-binding molecules. Little is known about the role
of chondroitin sulfate proteoglycans in the growth and guidance of axons in vivo.
To address this question, we examined the effects of exogenous soluble
chondroitin sulfates on the growth and guidance of axons arising from a
subpopulation of neurons in the vertebrate brain which express NOC-2, a novel
glycoform of the neural cell adhesion molecule N-CAM. Intact brains of stage 28
Xenopus embryos were unilaterally exposed to medium containing soluble exogenous
chondroitin sulfates. When exposed to chondroitin sulfate, NOC-2(+) axons within
the tract of the postoptic commissure failed to follow their normal trajectory
across the ventral midline via the ventral commissure in the midbrain. Instead,
these axons either stalled or grew into the dorsal midbrain or continued growing
longitudinally within the ventral longitudinal tract. These findings suggest that
chondroitin sulfate proteoglycans indirectly modulate the growth and guidance of
a subpopulation of forebrain axons by regulating either matrix-bound or cell
surface cues at specific choice points within the developing vertebrate brain.
PMID- 9769176
TI - Glycosylphosphatidylinositol-anchored cell surface proteins regulate position
specific cell affinity in the limb bud.
AB - Although regional differences in mesenchymal cell affinity in the limb bud
represent positional identity, the molecular basis for cell affinity is poorly
understood. We found that treatment of the cell surface with bacterial
phosphatidylinositol-specific phospholipase C (PI-PLC) could change cell affinity
in culture. When PI-PLC was added to the culture medium, segregation of the
progress zone (PZ) cells from different stage limb buds was inhibited. Similarly,
sorting out of the cells from different positions along the proximodistal (PD)
axis of the same stage limb buds was disturbed. Since PI-PLC can remove
glycosylphosphatidylinositol (GPI)-anchored membrane bound proteins from the cell
surface, the GPI-anchored cell surface proteins may be involved in sorting out.
To define the GPI-anchored molecules that determine the segregation of limb
mesenchymal cells, we examined the effect of neutralizing antibody on the EphA4
receptor that binds to GPI-anchored cell surface ligands, called ephrin-A.
Sorting out of the PZ cells at different stages could be inhibited by the
neutralizing antibody to EphA4. These results suggest that EphA4 and its GPI
anchored ligands are, at least in part, involved in sorting out of limb
mesenchymal cells with different proximal-distal positional values, and that GPI
anchored cell surface proteins play important roles in determining cell affinity
in the limb bud.
PMID- 9769177
TI - Experimental induction of BMP-4 expression leads to apoptosis in the paraxial and
lateral plate mesoderm.
AB - In the avian embryo, epithelialization of the segmental plate and formation of an
epithelial dermomyotome depend on signals from the neural tube and the ectoderm
overlying the paraxial mesoderm. In this study, we report that ectoderm removal
in combination with barrier insertion between the axial organs and the segmental
plate leads to an induction of BMP-4 expression in the paraxial mesoderm. In the
lateral plate, ectoderm removal alone leads to an increase of BMP-4 expression.
Application of BMP-4 protein results in a lack of epithelialization of the
paraxial mesoderm. In order to investigate whether the loss of epithelial
structures after these manipulations can be attributed to a change in cell fate,
a change in cell proliferation, or the induction of apoptosis, the paraxial
mesoderm was tested for expression of Msx-2, BMP-2, BMP-4, and BMP-7. Moreover,
BrdU and TUNEL staining were carried out. The inhibition of epithelialization
after ectoderm removal alone and after segregation of the axial organs is
accompanied neither by an increase in apoptosis nor by a reduction of the
proliferation rate in the paraxial mesoderm. On the other hand, an ectopic BMP-4
expression in the paraxial mesoderm after ectoderm removal in combination with
barrier insertion coincides with the occurrence of apoptotic cells and reduction
of proliferation rate in this tissue. Increase of apoptosis and decrease in cell
proliferation are observed in the paraxial and lateral plate mesoderm also after
application of BMP-4 protein.
PMID- 9769178
TI - Regulation of the trunk-tail patterning in the ascidian embryo: a possible
interaction of cascades between lithium/beta-catenin and localized maternal
factor pem.
AB - Embryonic cell specification and pattern formation in the ascidian embryo are
controlled by prelocalized egg cytoplasmic determinants. In previous studies, we
showed that overexpression of a maternal gene